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Papers: 10 Dec 2022 - 16 Dec 2022

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A nociceptive neuronal ensemble in the dorsomedial prefrontal cortex underlies pain chronicity.

Pain chronicity involves unpleasant experience in both somatosensory and affective aspects, accompanied with the prefrontal cortex (PFC) neuroplastic alterations. However, whether specific PFC neuronal ensembles underlie pain chronicity remains elusive. Here we identify a nociceptive neuronal ensemble in the dorsomedial prefrontal cortex (dmPFC), which shows prominent reactivity to nociceptive stimuli. We observed that this ensemble shows distinct molecular characteristics and is densely connected to pain-related regions including basolateral amygdala (BLA) and lateral parabrachial nuclei (LPB). Prolonged chemogenetic activation of this nociceptive neuronal ensemble, but not a randomly transfected subset of dmPFC neurons, induces chronic pain-like behaviors in normal mice. By contrast, silencing the nociceptive dmPFC neurons relieves both pain hypersensitivity and anxiety in mice with chronic inflammatory pain. These results suggest the presence of specific dmPFC neuronal ensembles in processing nociceptive information and regulating pain chronicity.

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A nigro-subthalamo-parabrachial pathway modulates pain-like behaviors.

The basal ganglia including the subthalamic nucleus (STN) and substantia nigra pars reticulata (SNr) are involved in pain-related responses, but how they regulate pain processing remains unknown. Here, we identify a pathway, consisting of GABAergic neurons in the SNr (SNr) and glutamatergic neurons in the STN (STN) and the lateral parabrachial nucleus (LPB), that modulates acute and persistent pain states in both male and female mice. The activity of STN neurons was enhanced in acute and persistent pain states. This enhancement was accompanied by hypoactivity in SNr neurons and strengthening of the STN-LPB glutamatergic projection. Reversing the dysfunction in the SNr-STN-LPB pathway attenuated activity of LPB neurons and mitigated pain-like behaviors. Therefore, the SNr-STN-LPB pathway regulates pathological pain and is a potential target for pain management.

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An anti-OX40 antibody to treat moderate-to-severe atopic dermatitis: a multicentre, double-blind, placebo-controlled phase 2b study.

OX40 is crucial for T-cell differentiation and memory induction. The anti-OX40 antibody, rocatinlimab inhibits the OX40 pathway. We evaluated the efficacy and safety of rocatinlimab in adults with moderate-to-severe atopic dermatitis.

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Mechanisms and treatments of neuropathic itch in a mouse model of lymphoma.

Our understanding of neuropathic itch is limited, due to the lack of relevant animal models. Patients with cutaneous T-cell lymphoma (CTCL) suffer from severe itching. Here we characterize a mouse model of chronic itch with remarkable lymphoma growth, immune cell accumulation, and persistent pruritus. Intradermal CTCL inoculation produces time-dependent changes in nerve innervations in lymphoma-bearing skin. In the early-phase (20 days), CTCL causes hyper-innervations in the epidermis. However, chronic itch is associated with loss of epidermal nerve fibers in the late-phases (40 and 60 days). CTCL is also characterized by marked nerve innervations in mouse lymphoma. Blockade of C-fibers reduced pruritus at early- and late-phases, whereas blockade of A-fibers only suppressed late-phase itch. Intrathecal gabapentin injection reduced late-phase but not early-phase pruritus. IL-31 is upregulated in mouse lymphoma, while its receptor Il31ra was persistently upregulated in Trpv1-expressing sensory neurons in CTCL mice. Intratumoral anti-IL-31 treatment effectively suppressed CTCL-induced scratching and alloknesis (mechanical itch). Finally, intrathecal administration of TLR4 antagonist attenuated pruritus in early and late phases and in both sexes. Collectively, we have established a mouse model of neuropathic and cancer itch with relevance to human disease. Our findings also suggest distinct mechanisms underlying acute, chronic, and neuropathic itch.

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Pain research in 2022: nociceptors and central sensitisation.

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Thalamocortical circuits drive remifentanil-induced postoperative hyperalgesia.

Remifentanil-induced hyperalgesia (RIH) is a severe but common postoperative clinical problem with elusive underlying neural mechanisms. Here, we discovered that glutamatergic neurons in the thalamic ventral posterolateral nucleus (VPLGlu) exhibited significantly elevated burst firing accompanied by upregulation of Cav3.1 T-type calcium channel expression and function in RIH model mice. In addition, we identified a glutamatergic neuronal thalamocortical circuit in the VPL projecting to hindlimb primary somatosensory cortex glutamatergic neurons (S1HLGlu) that mediated RIH. In vivo calcium imaging and multi-tetrode recordings revealed heightened S1HLGlu neuronal activity during RIH. Moreover, preoperative suppression of Cav3.1-dependent burst firing in VPLGlu neurons or chemogenetic inhibition of VPLGlu neuronal terminals in the S1HL abolished the increased S1HLGlu neuronal excitability while alleviating RIH. Our findings suggest that remifentanil induces postoperative hyperalgesia by upregulating T-type calcium channel-dependent burst firing in VPLGlu neurons to activate S1HLGlu neurons, thus revealing an ion channel-mediated neural circuit basis for RIH that can guide analgesic development.

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TIAM1-mediated synaptic plasticity underlies comorbid depression-like and ketamine antidepressant-like actions in chronic pain.

Chronic pain often leads to depression, increasing patient suffering and worsening prognosis. While hyperactivity of the anterior cingulate cortex (ACC) appears to be critically involved, the molecular mechanisms underlying comorbid depressive symptoms in chronic pain remain elusive. T cell lymphoma invasion and metastasis 1 (Tiam1) is a Rac1 guanine nucleotide exchange factor (GEF) that promotes dendrite, spine, and synapse development during brain development. Here, we show that Tiam1 orchestrates synaptic structural and functional plasticity in ACC neurons via actin cytoskeleton reorganization and synaptic N-methyl-d-aspartate receptor (NMDAR) stabilization. This Tiam1-coordinated synaptic plasticity underpins ACC hyperactivity and drives chronic pain-induced depressive-like behaviors. Notably, administration of low-dose ketamine, an NMDAR antagonist emerging as a promising treatment for chronic pain and depression, induces sustained antidepressant-like effects in mouse models of chronic pain by blocking Tiam1-mediated maladaptive synaptic plasticity in ACC neurons. Our results reveal Tiam1 as a critical factor in the pathophysiology of chronic pain-induced depressive-like behaviors and the sustained antidepressant-like effects of ketamine.

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HAP1 inhibition contributes to neuropathic pain by suppressing Cav1.2 activity and attenuating inflammation.

Although pain dysfunction is increasingly observed in Huntington disease (HD), the underlying mechanisms still unknown. As a crucial huntington-associated protein, HAP1 is enriched in normal spinal dorsal horn and dorsal root ganglia (DRG) where are regarded as "primary sensory center", indicating its potential functions in pain process. Here, we discovered that HAP1 level was greatly increased in the dorsal horn and DRG under acute and chronic pain conditions. Lack of HAP1 obviously suppressed mechanical allodynia and hyperalgesia in spared nerve injury (SNI)- and chronic constriction injury (CCI)-induced pain. Its deficiency also greatly inhibited the excitability of nociceptive neurons. Interestingly, we found that suppressing HAP1 level diminished the membrane expression of the L-type calcium channel (Cav1.2), which can regulate Ca2+ influx and then influence BDNF synthesis and release. Furthermore, SNI-induced activation of astrocytes and microglia notably decreased in HAP1 deficient mice. These results indicate that HAP1 deficiency might attenuate pain responses. Collectively, our results suggest that HAP1 in dorsal horn and DRG neurons regulates Cav1.2 surface expression, which in turn reduces neuronal excitability, BDNF secretion and inflammatory responses and ultimately influences neuropathic pain progression.

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Selective androgen receptor modulator microparticle formulation reverses muscle hyperalgesia in a mouse model of widespread muscle pain.

Chronic pain is a significant health problem associated with disability and reduced quality of life. Current management of chronic pain is inadequate with only modest effects of pharmacological interventions. Thus, there is a need for the generation of analgesics for treating chronic pain. While preclinical and clinical studies demonstrate the analgesic effects of testosterone, clinical use of testosterone is limited by adverse androgenic effects. Selective androgen receptor modulators (SARMs) activate androgen receptors and overcome treatment limitations by minimizing androgenic side effects. Thus, we tested if daily soluble SARMs or a SARM-loaded microparticle formulation alleviated muscle hyperalgesia in a mouse-model of widespread pain (male and female C57BL/6J mice). We tested if the analgesic effects of the SARM-loaded microparticle formulation was mediated through androgen receptors by blocking androgen receptors with flutamide pellets. In vitro and in vivo release kinetics were determined for SARM-loaded microparticles. Safety and toxicity of SARM treatment was determined using serum cardiac and liver toxicity panels, heart histology, and conditioned place preference testing. Subcutaneous daily SARM administration, and 2 injections, I week apart, of SARM-loaded microparticles alleviated muscle hyperalgesia in both sexes and was prevented with flutamide treatment. Sustained release of SARM, from the microparticle formulation, was observed both in vitro and in vivo for 4 weeks. SARM treatment produced no cardiac or liver toxicity and did not produce rewarding behaviors. These studies demonstrate SARM-loaded microparticles alleviate muscle pain, release drug for a sustained period, are safe, and may serve as a potential therapeutic for chronic muscle pain.

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Headache research in 2022: advances and remaining challenges.

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DECREASED DEFAULT MODE NETWORK CONNECTIVITY FOLLOWING 24 HOURS OF CAPSAICIN-INDUCED PAIN PERSISTS DURING IMMEDIATE PAIN RELIEF AND FACILITATION.

Prolonged experimental pain can help assess cortical mechanisms underlying the transition from acute to chronic pain such as resting-state functional connectivity (rsFC), especially in early stages. This crossover study determined the effects of 24-hour-capsaicin-induced pain on the default mode network rsFC, a major network in the dynamic pain connectome. Electroencephalographic rsFC measured by Granger causality was acquired from 24 healthy volunteers (12 women) at baseline, 1hour, and 24hours following a control or capsaicin patch on the right forearm. The control patch was received maximum one week before the capsaicin patch. Following 24hours, the patch was cooled and later heated to assess rsFC changes in response to pain relief and facilitation, respectively. Compared to baseline, decreased rsFC at alpha oscillations (8-10Hz) was found following 1hour and 24hours of capsaicin application for connections projecting from medial prefrontal cortex (mPFC) and right angular gyrus (rAG) but not left angular gyrus (lAG) or posterior cingulate cortex (PCC): mPFC-PCC (1hour:P<0.001, 24hours_P=0.002), mPFC-rAG (1hour:P<0.001, 24hours_P=0.001), rAG-mPFC (1hour:P<0.001, 24hours_P=0.001), rAG-PCC (1hour:P<0.001, 24hours_P=0.004). Comparable decreased rsFC following 1hour and 24hours (P≤0.008) was found at beta oscillations, however, decreased projections from PCC were also found: PCC-rAG (P≤0.005) and PCC-lAG (P≤0.006). Pain NRS scores following 24hours (3.7±0.4) was reduced by cooling (0.3±0.1, P=0.004) and increased by heating (4.8±0.6, P=0.016). However, neither cooling nor heating altered rsFC. This study shows that 24hours of experimental pain induces a robust decrease in DMN connectivity that persists during pain relief or facilitation suggesting a possible shift to attentional and emotional processing in persistent pain. Perspective: This article shows decreased DMN connectivity that might reflect possible attentional and emotional changes during acute and prolonged pain. Understanding these changes could potentially help clinicians in developing therapeutic methods that can better target these attentional and emotional processes before developing into more persistent states.

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Cells that drive chronic pain are found in mouse brains.

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Bestrophin-1 participates in neuropathic pain induced by spinal nerve transection but not spinal nerve ligation.

Previous studies have reported that L5/L6 spinal nerve ligation (SNL), but not L5 spinal nerve transection (SNT), enhances anoctamin-1 in injured and uninjured dorsal root ganglia (DRG) of rats suggesting some differences in function of the type of nerve injury. The role of bestrophin-1 in these conditions is unknown. The aim of this study was to investigate the role of bestrophin-1 in rats subjected to L5 spinal nerve transection (SNT) and L5/L6 spinal nerve ligation (SNL). SNT up-regulated bestrophin-1 protein expression in injured L5 and uninjured L4 DRG at day 7, whereas it enhanced GAP43 mainly in injured, but also in uninjured DRG. In contrast, SNL enhanced GAP43 at day 1 and 7, while bestrophin-1 expression increased only at day 1 after nerve injury. Accordingly, intrathecal injection of the bestrophin-1 blocker CaCC (1-10 µg) reverted SNT- or SNL-induced tactile allodynia in a concentration-dependent manner. Intrathecal injection of CaCC (10 µg) prevented SNT-induced upregulation of bestrophin-1 and GAP43 at day 7. In contrast, CaCC did not affect SNL-induced up-regulation of GAP43 nor bestrophin-1. Bestrophin-1 was mainly expressed in small- and medium-size neurons in naïve rats, while SNT increased bestrophin-1 immunoreactivity in CGRP+, but not in IB4+ neuronal cells in DRG. Intrathecal injection of bestrophin-1 plasmid (pCMVBest) induced tactile allodynia and increased bestrophin-1 expression in DRG and spinal cord in naïve rats. CaCC reversed bestrophin-1 overexpression-induced tactile allodynia and restored bestrophin-1 expression. Our data suggest that bestrophin-1 plays a relevant role in neuropathic pain induced by SNT, but not by SNL. Perspective: SNT, but not SNL, up-regulates bestrophin-1 and GAP43 protein expression in injured L5 and uninjured L4 DRG. Moreover, SNT increases bestrophin-1 immunoreactivity in CGRP+ neurons in DRG, while bestrophin-1 overexpression induces allodynia. CaCC reduces allodynia and restores bestrophin-1 expression induced by bestrophin-1 transfection. Our data suggest that spinal bestrophin-1 in DRG is differentially regulated depending on the neuropathic pain model.

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Opioid-induced hyperalgesia: Are thalamic T-type calcium channels treatment targets?

Opioid-induced hyperalgesia (OIH) is a state of paradoxically enhanced pain transmission, termed nociceptive sensitization, described to occur in both humans and animals after repeated administration of opioid drugs, including rapidly acting remifentanil. However, molecular mechanisms of OIH remain understudied. In this issue of the JCI, Yan Jin and colleagues provided strong evidence that hyperexcitable thalamocortical networks drive remifentanil-induced hyperalgesia in a rodent model of postsurgical pain. Furthermore, the authors specifically identified an important role of the CaV3.1 isoform of low-voltage-activated or T-type calcium channels (T-channels) in this process. Further experiments are needed to determine whether thalamic T channels could serve as targets for the treatment of OIH.

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Genetic risk factors for ME/CFS identified using combinatorial analysis.

Myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) is a debilitating chronic disease that lacks known pathogenesis, distinctive diagnostic criteria, and effective treatment options. Understanding the genetic (and other) risk factors associated with the disease would begin to help to alleviate some of these issues for patients.

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Multimorbidity and Sickness Absence/Disability Pension in Cluster Headache Patients and Matched References: A Swedish Register-Based Study.

Multimorbidity among cluster headache (CH) patients is considered to be high, but large studies are lacking. The aims were to explore the occurrence of diagnosis-specific multimorbidity among CH patients and matched references and possible associations of this with their sickness absence and disability pension.

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Mirogabalin for Central Neuropathic Pain After Spinal Cord Injury: A Randomized, Double-Blind, Placebo-Controlled, Phase 3 Study in Asia.

Patients with spinal cord injury (SCI) commonly experience central neuropathic pain (CNeP), which is challenging to treat. Mirogabalin is effective for peripheral neuropathic pain, but evidence for CNeP is lacking.

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Trial of Beremagene Geperpavec (B-VEC) for Dystrophic Epidermolysis Bullosa.

Dystrophic epidermolysis bullosa is a rare genetic blistering skin disease caused by mutations in , which encodes type VII collagen (C7). Beremagene geperpavec (B-VEC) is a topical investigational herpes simplex virus type 1 (HSV-1)-based gene therapy designed to restore C7 protein by delivering .

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Microembolism and Other Links Between Migraine and Stroke: Clinical and Pathophysiologic Update.

Migraine and stroke are highly prevalent diseases with a high impact on quality of life, with multiple epidemiological, pathophysiological, clinical, and prognostic areas of overlap. Migraine is a risk factor for stroke. This risk is explained by common risk factors, migraine-specific mechanisms, and non-migraine-specific mechanisms that have a relevant role in patients with migraine with aura (e.g., atrial fibrillation, paradoxical embolism through a patent foramen ovale). Another important link between migraine aura and ischemic stroke is cardiac embolism. Cardioembolism is the most frequent cause of ischemic stroke and increasing evidence suggests that microembolism, predominantly but not exclusively originating in the heart, is a contributing mechanism to the development of migraine aura. In this review, we discuss epidemiological aspects of the association between migraine and ischemic stroke, the clinical presentation of ischemic strokes in patients with migraine, and the differentiation between migrainous and non-migrainous infarctions. After that, we review migraine-specific and non-migraine-specific stroke mechanisms. We then review updated preclinical and clinical data on microembolism as a cause of migraine aura. In the last section, we summarize knowledge gaps and important areas to explore in future research. The review includes a clinical vignette with a discussion of the most relevant topics addressed.

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Disruption of C/EBPβ-Clec7a axis exacerbates neuroinflammatory injury via NLRP3 inflammasome-mediated pyroptosis in experimental neuropathic pain.

Growing evidence shows that C-Type Lectin Domain Containing 7A (Clec7a) may be involved into neuroinflammatory injury of various neurological diseases. However, its roles in neuropathic pain remain unclear.

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Determining profiles of pain-specific and general emotion regulation skills and their relation to 12-month outcomes among people with chronic pain.

Difficulties with pain-specific emotion regulation (ER; e.g., pain catastrophizing, pain acceptance) are associated with poor pain outcomes. Less is known about how general ER relates to pain outcomes, or the extent to which pain-specific and general ER interact. In a sample (N = 1453) of adults with chronic pain, the current study used latent profile analysis to identify subgroups of people with distinct pain-specific and general ER profiles, and determined how subgroup membership at baseline related to pain severity, pain interference, depression and anxiety symptoms at 12-month follow-up. Four groups were identified: (1) general ER difficulties only (29.6%); (2) pain-specific and general ER difficulties (26.3%); (3) skillful pain-specific and general ER (24.6%); (4) pain-specific ER difficulties only (19.4%). Controlling for auto-correlation and demographic covariates, those with pain-specific and general ER difficulties had the worst outcomes in all domains. Membership to other groups did not differentiate between pain severity or interference outcomes; those skillful in pain-specific and general ER had the lowest depression and anxiety symptoms at 12-months. General ER difficulties are common among adults with chronic pain and raise relative risk when paired with pain-specific ER difficulties. Findings offer potential directions for individualizing pain psychology treatment. Perspective This article shows that people with chronic pain have different sets of strengths and difficulties when it comes to regulating emotions related and/or unrelated to the experience of pain itself. Understanding an individual's unique constellation of emotion regulation skills and difficulties might help personalize the psychological treatment of pain.

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Extracellular vesicles from IFN-γ-primed mesenchymal stem cells repress atopic dermatitis in mice.

Atopic dermatitis (AD) is a chronic inflammatory skin disorder characterized by immune dysregulation, pruritus, and abnormal epidermal barrier function. Compared with conventional mesenchymal stem cell (MSC), induced pluripotent stem cell (iPSC)-derived mesenchymal stem cell (iMSC) is recognized as a unique source for producing extracellular vesicles (EVs) because it can be obtained in a scalable manner with an enhanced homogeneity. Stimulation of iMSCs with inflammatory cytokines can improve the immune-regulatory, anti-inflammatory, and tissue-repairing potential of iMSC-derived EVs.

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Schwann cell stimulation induces functional and structural changes in peripheral nerves.

Signal propagation is the essential function of nerves. Lysophosphatidic acid 18:1 (LPA) allows the selective stimulation of calcium signaling in Schwann cells but not neurons. Here, the time course of slowing and amplitude reduction on compound action potentials due to LPA exposure was observed in myelinated and unmyelinated fibers of the mouse, indicating a clear change of axonal function. Teased nerve fiber imaging showed that Schwann cell activation is also present in axon-attached Schwann cells in freshly isolated peripheral rat nerves. The LPA receptor 1 was primarily localized at the cell extensions in isolated rat Schwann cells, suggesting a role in cell migration. Structural investigation of rat C-fibers demonstrated that LPA leads to an evagination of the axons from their Schwann cells. In A-fibers, the nodes of Ranvier appeared unchanged, but the Schmidt-Lanterman incisures were shortened and myelination reduced. The latter might increase leak current, reducing the potential spread to the next node of Ranvier and explain the changes in conduction velocity. The observed structural changes provide a plausible explanation for the functional changes in myelinated and unmyelinated axons of peripheral nerves and the reported sensory sensations such as itch and pain.

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Lidocaine alleviates inflammation and pruritus in atopic dermatitis by blocking different population of sensory neurons.

Atopic dermatitis (AD) is a common chronic pruritic inflammatory skin disease that relies on neuro-immune communication while neuronal mechanism-based therapeutic attempts remain lacking. We sought to investigate the efficacy of intravenous lidocaine therapy on AD and underlying neuro-immune mechanism.

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Spinal pain processing in arthritis: neuron and glia (inter)actions.

Diseases of joints are among the most frequent causes of chronic pain. In the course of joint diseases the peripheral and the central nociceptive system develop persistent hyperexcitability (peripheral and central sensitization). This review addresses the mechanisms of spinal sensitization evoked by arthritis. Electrophysiological recordings in anaesthetized rats from spinal cord neurons with knee input in a model of acute arthritis showed that acute spinal sensitization is dependent on spinal glutamate receptors (AMPA, NMDA and metabotropic glutamate receptors) and supported by spinal actions of neuropeptides such as neurokinins and CGRP, by prostaglandins, and by proinflammatory cytokines. In several chronic arthritis models (including immune-mediated arthritis and osteoarthritis) spinal glia activation was observed to be coincident with behavioral mechanical hyperalgesia which was attenuated or prevented by intrathecal application of minocycline, fluorocitrate and pentoxyfylline. Some studies identified specific pathways of micro- and astroglia activation such as the purinoceptor- (P X -) cathepsin S/CX CR1 pathway, the mobility group box-1 protein (HMGB1) and toll-like receptor 4 (TLR4) activation, spinal NFκB/p65 activation and others. The spinal cytokines TNF, interleukin-6, interleukin-1β and others form a functional spinal network characterized by an interaction between neurons and glia cells which is required for spinal sensitization. Neutralization of spinal cytokines by intrathecal interventions attenuates mechanical hyperalgesia. This effect may in part result from local suppression of spinal sensitization and in part from efferent effects which attenuate the inflammatory process in the joint. In summary, arthritis evokes significant spinal hyperexcitability which is likely to contribute to the phenotype of arthritis pain in patients.

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Issues in design, conduct, and conclusions of JAMA’s Hara et al.’s randomized clinical trial of spinal cord burst stimulation versus placebo stimulation on disability in patients with chronic radicular pain after lumbar spine surgery.

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‘Relieving’ the year of 2022 in .

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CGRP-dependent sensitization of PKC-δ positive neurons in central amygdala mediates chronic migraine.

To investigate specific brain regions and neural circuits that are responsible for migraine chronification.

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Increased overall morbidity in women with endometriosis: a population-based follow-up study until age 50.

To investigate whether there is an association between endometriosis and nongynecological diseases in the general female population by age 50?

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Chronic pain inhibits autophagy in hippocampus while the analgetic drug, Gabapentin reverts this SNI-driven action.

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The contribution of psychological flexibility to functioning in people living with cancer-related pain.

Studies of individuals with non-cancer-related chronic pain, find that higher levels of psychological flexibility (PF) are associated with less distress, better functioning, and a better response to treatment. People diagnosed with cancer are at significantly increased risk of developing chronic cancer-related pain, the presence of which is associated with poorer health outcomes. Little is known about whether PF is applicable to cancer pain. The current study investigates the relationship between chronic cancer-related pain, distress and functioning, and three theoretical processes proposed by the PF model: pain acceptance, present-moment focus, and committed action.

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Associations among acute and chronic musculoskeletal pain, sleep duration, and C-reactive protein (CRP): A cross-sectional study of the UK biobank dataset.

Both musculoskeletal pain and sleep disturbances are major health problems worldwide. Literature suggests that the two are reciprocally related and both may be associated with changes in C-reactive protein (CRP) levels. However, the relationships among musculoskeletal pain, sleep duration, and CRP remain unclear. In this cross-sectional study, we investigated the relationship between acute and chronic musculoskeletal pain, sleep, and inflammation using the data from the initial visit of the UK Biobank. 17,642 individuals with chronic musculoskeletal pain, 11,962 individuals with acute musculoskeletal pain, and 29,604 pain-free controls were included in the analysis. In addition, we validated the findings using data from the second visit assessment of the UK Biobank. We found that 1) chronic pain was associated with higher CRP levels compared to both acute pain and the pain-free controls; 2) chronic pain was associated with a lower sleep score (a measurement of sleep patterns), compared to acute pain and the pain-free controls; and acute pain was associated with lower sleep scores compared to the controls; 3) there was a significant negative association between the sleep score and CRP; 4) CRP may partially mediate the association between chronic pain and decreased sleep score. However, the effect size of the mediation was rather small, and the pathophysiological significance remains uncertain. Further validation is needed. These findings were partly replicated in the UK Biobank second visit assessment cohort with a smaller sample size. Our findings, which are based on the large UK Biobank dataset, support the interplay between musculoskeletal pain, sleep patterns, and the potential mediating role of CRP on this reciprocal relationship.

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An investigation of metabolome in blood in patients with chronic peripheral, posttraumatic/postsurgical neuropathic pain.

Neuropathic pain (NP) is a chronic pain condition resulting from a lesion or disease in the somatosensory nervous system. The aim of this study was to investigate the metabolome in plasma from patients with chronic peripheral, posttraumatic/postsurgical NP compared to healthy controls. Further, we aimed to investigate the correlation between pain intensity and the metabolome in plasma. The metabolic profile in plasma samples from 16 patients with chronic NP and 12 healthy controls was analyzed using a nuclear magnetic resonance spectroscopy method. Information about pain intensity, pain duration, body mass index (BMI), age, sex, and blood pressure were obtained through a questionnaire and clinical examination. Multivariate data analysis was used to identify metabolites significant for group separation and their correlation with pain intensity and duration, BMI, and age. We found 50 out of 326 features in plasma significantly contributing to group discrimination between NP and controls. Several of the metabolites that significantly differed were involved in inflammatory processes, while others were important for central nervous system functioning and neural signaling. There was no correlation between pain intensity and levels of metabolite in NP. These findings indicate that there seems to be peripheral/systemic differences in the metabolic profile between patients with chronic NP and healthy individuals.

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Predicting Disease Activity in Rheumatoid Arthritis with the Fibromyalgia Survey Questionnaire: Does the Severity of Fibromyalgia Symptoms Matter?

To determine if the degree of baseline fibromyalgia symptoms in patients with rheumatoid arthritis (RA), as indicated by the Fibromyalgia Survey Questionnaire (FSQ) score, predicts RA disease activity after initiation or change of a disease-modifying antirheumatic drug (DMARD).

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The anterior cingulate cortex contributes to the analgesic rather than the anxiolytic effects of duloxetine in chronic pain-induced anxiety.

Mood disorders, such as anxiety and depression, are commonly found in people suffering from chronic pain. Serotonin-norepinephrine reuptake inhibitors (SNRIs) are potential in alleviating chronic pain and are the first-line option for anxiety disorder. The anterior cingulate cortex (ACC) plays a vital role in chronic pain-induced anxiety, but its role in the therapeutic effects of SNRIs remains largely unclear. We used complete Freund's adjuvant (CFA) in this current study to induce chronic inflammatory pain. Von Frey test was used to measure the mechanical withdrawal threshold. The elevated plus maze test (EPM) and the novelty-suppressed feeding test (NSF) were used to measure anxiety-like behaviors. Twenty-one days after the modeling, anxiety-like behaviors were successfully induced in CFA mice, and a 3-day intraperitoneal injection of duloxetine attenuated such behaviors. While, mechanical hyperalgesia was also improved. Then, we locally infused duloxetine in ACC for 3 days only to find out its analgesic effect in CFA mice. Furthermore, we used fiber photometry to discover decreased glutamatergic excitability and enhanced serotonin concentration in ACC after intraperitoneal injection of duloxetine. Overall, this study proposed a potential mechanism for the analgesic effect of duloxetine and shed light on further studies on the mechanism of its anxiolytic effect in chronic pain-induced anxiety.

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Association of cannabis and/or opioid with quality of life and healthcare utilization in patients with chronic pain.

Opioids have been commonly used to treat chronic pain, but they are associated with significant morbidity and mortality. Cannabis has been advocated as an alternative; however, a growing number of patients are now using a combination of opioid and cannabis and the impact of this combination is not well-studied.

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Changed cerebral function and morphology serve as neuroimaging evidence for subclinical type 2 diabetic polyneuropathy.

Central and peripheral nervous systems are all involved in type 2 diabetic polyneuropathy mechanisms, but such subclinical changes and associations remain unknown. This study aims to explore subclinical changes of the central and peripheral and unveil their association.

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The Helplessness Dimension of Pain Catastrophizing Mediates the Relation between PTSD Symptoms and Pain Rehabilitation Measures.

Comorbid chronic pain and post-traumatic stress disorder (PTSD) complicate the treatment of both conditions. Previous research has identified pain catastrophizing as a potentially important variable contributing to the relationship between chronic pain and PTSD. However, little is known regarding how the different dimensions of pain catastrophizing-rumination, magnification, and helplessness-uniquely contribute to the relationship between PTSD symptomatology and measures of pain outcome.

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Spinal cord dorsal horn sensory gate in preclinical models of chemotherapy-induced painful neuropathy and contact dermatitis chronic itch becomes less leaky with gene expression-enhancing treatments.

Low intraneuronal chloride in spinal cord dorsal horn (SCDH) pain relay neurons is of critical relevance for physiological transmission of primary sensory afferents because low intraneuronal chloride dictates GABA-ergic and glycin-ergic neurotransmission to be inhibitory. If neuronal chloride rises to unphysiological levels, the primary sensory gate in the spinal cord dorsal horn becomes corrupted, with resulting behavioral hallmarks of hypersensitivity and allodynia, for example in pathological pain. Low chloride in spinal cord dorsal horn neurons relies on the robust gene expression of and sustained transporter function of the KCC2 chloride-extruding electroneutral transporter. Based on a recent report where we characterized the GSK3-inhibitory small molecule, kenpaullone, as a gene expression-enhancer that potently repaired diminished expression and KCC2 transporter function in SCDH pain relay neurons, we extend our recent findings by reporting (i) effective pain control in a preclinical model of taxol-induced painful peripheral neuropathy that was accomplished by topical application of a TRPV4/TRPA1 dual-inhibitory compound (compound 16-8), and was associated with the repair of diminished gene expression in the SCDH; and (ii) potent functioning of kenpaullone as an antipruritic in a DNFB contact dermatitis preclinical model. These observations suggest that effective peripheral treatment of chemotherapy-induced painful peripheral neuropathy impacts the pain-transmitting neural circuit in the SCDH in a beneficial manner by enhancing gene expression, and that chronic pruritus might be relayed in the primary sensory gate of the spinal cord, following similar principles as pathological pain, specifically relating to the critical functioning of gene expression and the KCC2 transporter function.

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Quantitative proteomic analysis of cerebrospinal fluid from patients with idiopathic facial nerve palsy.

Idiopathic facial palsy (IFP) accounts for over 60% of peripheral facial palsy (FP) cases. The cause of IFP remains to be determined. Possible etiologies are nerve swelling due to inflammation and/or viral infection. Here, we applied an integrative mass spectrometry approach to identify possibly altered protein patterns in the CSF of IFP patients.

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A Novel Pulsed Stimulation Pattern in Spinal Cord Stimulation: Clinical Results and Postulated Mechanisms of Action in the Treatment of Chronic Low Back and Leg Pain.

The aim of this article is to discuss the possible mechanisms of action (MOAs) and results of a pilot study of a novel, anatomically placed, and paresthesia-independent, neurostimulation waveform for the management of chronic intractable pain.

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Nerve injury-induced upregulation of apolipoprotein E in dorsal root ganglion participates in neuropathic pain in male mice.

Apolipoprotein E (ApoE) is an apolipoprotein involved in lipid metabolism and is primarily responsible for lipid transport and cholesterol homeostasis in the central nervous system (CNS). The aim of this study is to explore the role of ApoE in the pathological development of neuropathic pain. First, we examined the location of ApoE in the dorsal root ganglion (DRG) and spinal cord in male mice using immunohistochemistry, and found that ApoE was predominantly expressed in DRG satellite glial cells (SGCs) and macrophages and spinal cord astrocytes. Using a spinal nerve ligation (SNL)-induced neuropathic pain mouse model, we found that nerve injury caused an increase in ApoE expression in the injured DRGs, but not in the spinal cord after SNL surgery. Furthermore, we observed reduced SNL-induced pain hypersensitivity in ApoE knockout mice compared to wild-type mice. Moreover, an antisense oligonucleotide (ASO) targeting the Apoe gene sequence, which was microinjected into the DRG or administered intrathecally, not only reduced ApoE expression in DRG but also attenuated SNL-induced pain hypersensitivity. Finally, we found that a tyrosine kinase receptor AXL, which was previously demonstrated to contribute to neuropathic pain, may mediate ApoE function under neuropathic pain condition. In conclusion, our data suggest that ApoE in DRG promote pain hypersensitivity via the DRG membrane receptor AXL in neurons under neuropathic pain conditions. This study revealed a novel mechanism between lipid homeostasis and neuropathic pain.

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Electroacupuncture ameliorates knee osteoarthritis in rats via inhibiting NLRP3 inflammasome and reducing pyroptosis.

Knee Osteoarthritis (KOA), is the most common joint disease worldwide. The pathogenesis of KOA is complex and electroacupuncture (EA) is an effective therapy for KOA, but the mechanism remains unclear. In this study, we aim to investigate the potential therapeutic effect of EA on the rat model of KOA induced by monosodium iodoacetate (MIA) and its relationship with NLRP3 inflammasome by immunohistochemistry and western blot.

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The effect of topical ketamine administration on the corneal epithelium repair.

The cornea is regarded as a sensitive organ to pain. Ketamine can effectively reduce postoperative neuropathic pain. We hypothesized that topical ketamine could mitigate postoperative corneal neuropathic pain. The aim of this study was to determine whether topical ketamine is safe for cornea and evaluate its effect on the repair procedure the damaged corneal tissue. Our study was performed on only the right eyes of 15 male rats. All animals underwent general anesthesia and the whole corneal epithelium was removed. All subjects were divided into two groups: group 1 (n = 8), one drop of ketamine, and group 2 (n = 7), one drop of 0.9% sodium chloride administered topically on the scraped cornea every 6 h for 7 days. The rats' s cornea was carefully monitored daily for the size of epithelial defects under a microscope and was photographed. On the eighth day, the eyes were sent for pathological examination. The eyes were examined for the amount of inflammation, neovascularization, keratinization, epithelial thickness and Descemet's membrane pathologies. The epithelial defect has healed completely on the sixth day in all rats in both groups. There was no significant difference in the speed of complete recovery between the two groups. No significant difference was observed between the two groups in terms of inflammation grade, neovascularization grade, and epithelial thickness. Our study showed that topical ketamine had no significant effect on corneal wound healing in a rat animal model and could be used safely for the management of postoperative chronic ocular pain.

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Soluble epoxide hydrolase inhibition enhances Specialized Pro-resolving Lipid Mediator production and promotes macrophage plasticity.

Epoxyeicosatrienoic acids (EETs) and other epoxy fatty acids (EpFA) are lipid mediators that are rapidly inactivated by soluble epoxide hydrolase. Uncontrolled and chronic inflammatory disorders fail to sufficiently activate endogenous regulatory pathways, including the production of specialized pro-resolving mediators (SPMs). Here, we addressed the relationship between SPMs and the EET/sEH axis and explored the impact of sEH inhibition on resolving macrophage phenotype.

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Memristors with Nociceptor Characteristics Using Threshold Switching of Pt/HfO/TaOx/TaN Devices.

As artificial intelligence technology advances, it is necessary to imitate various biological functions to complete more complex tasks. Among them, studies have been reported on the nociceptor, a critical receptor of sensory neurons that can detect harmful stimuli. Although a complex CMOS circuit is required to electrically realize a nociceptor, a memristor with threshold switching characteristics can implement the nociceptor as a single device. Here, we suggest a memristor with a Pt/HfO/TaO/TaN bilayer structure. This device can mimic the characteristics of a nociceptor including the threshold, relaxation, allodynia, and hyperalgesia. Additionally, we contrast different electrical properties according to the thickness of the HfO layer. Moreover, Pt/HfO/TaO/TaN with a 3 nm thick HfO layer has a stable endurance of 1000 cycles and controllable threshold switching characteristics. Finally, this study emphasizes the importance of the material selection and fabrication method in the memristor by comparing Pt/HfO/TaO/TaN with Pt/TaO/TaN, which has insufficient performance to be used as a nociceptor.

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Impaired Pain Processing at a Brainstem Level Is Involved in Maladaptive Neuroplasticity in Patients with Chronic Complex Regional Pain Syndrome.

Neuroinflammatory mechanisms and maladaptive neuroplasticity underlie the progression of complex regional pain syndrome (CRPS), which is prototypical of central neuropathic pain conditions. While cortical maladaptive alterations are well described, little is known about the contribution of the brainstem to the pathophysiology. This study investigates the role of pain-modulatory brainstem pathways in CRPS using the nociceptive blink reflex (nBR), which not only provides a direct read-out of brainstem excitability and habituation to painful stimuli but may also be suitable for use as a diagnostic biomarker for CRPS. Thirteen patients with CRPS and thirteen healthy controls (HCs) participated in this prospective case-control study investigating the polysynaptic trigemino-cervical (R2) nBR response. The R2 area and its habituation were assessed following repeated supraorbital electrical stimulation. Between-group comparisons included evaluations of diagnostic characteristics as a potential biomarker for the disease. Patients with CRPS showed a substantial decrease in habituation on the stimulated (Cohen's d: 1.3; = 0.012) and the non-stimulated side (Cohen's d: 1.1; = 0.04). This is the first study to reveal altered nBR habituation as a pathophysiological mechanism and potential diagnostic biomarker in CRPS. We confirmed previous findings of altered nBR excitability, but the diagnostic accuracy was inferior. Future studies should investigate the nBR as a marker of progression to central mechanisms in CRPS and as a biomarker to predict treatment response or prognosis.

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An Altered Skin and Gut Microbiota Are Involved in the Modulation of Itch in Atopic Dermatitis.

Skin and gut microbiota play an important role in the pathogenesis of atopic dermatitis (AD). An alteration of the microbiota diversity modulates the development and course of AD, e.g., decreased microbiome diversity correlates with disease severity, particularly in lesional skin of AD. Itch is a hallmark of AD with unsatisfying treatment until now. Recent evidence suggests a possible role of microbiota in altering itch in AD through gut-skin-brain interactions. The microbial metabolites, proinflammatory cytokines, and impaired immune response lead to a modulation of histamine-independent itch, disruption of epidermal barrier, and central sensitization of itch mechanisms. The positive impact of probiotics in alleviating itch in AD supports this hypothesis, which may lead to novel strategies for managing itchy skin in AD patients. This review summarizes the emerging findings on the correlation between an altered microbiota and gut-skin-brain axis in AD, especially in modulating itchy skin.

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The reliability of two prospective cortical biomarkers for pain: EEG peak alpha frequency and TMS corticomotor excitability.

Many pain biomarkers fail to move from discovery to clinical application, attributed to poor reliability and an inability to accurately classify at-risk individuals. Preliminary evidence has shown that high pain sensitivity is associated with slow peak alpha frequency (PAF), and depression of corticomotor excitability (CME), potentially due to impairments in ascending sensory signalling and descending motor pathway signalling respectively NEW METHOD: The present study evaluated the reliability of PAF and CME responses during sustained pain. Specifically, we determined whether, over several days of pain, a) PAF remains stable and b) individuals show two stable and distinct CME responses: facilitation and depression. Participants were given an injection of nerve growth factor (NGF) into the right masseter muscle on Day 0 and Day 2, inducing sustained pain. Electroencephalography (EEG) to assess PAF and transcranial magnetic stimulation (TMS) to assess CME were recorded on Day 0, Day 2 and Day 5.

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Brodalumab: Efficacy, safety, and survival in mid-term (52 weeks) on real clinical practice in Andalucia, Spain.

Brodalumab is a recombinant monoclonal antibody (IgG2) that binds with high affinity to the human interleukin-17 (IL-17) receptor A and blocks the biological activity of the proinflammatory cytokines IL-17A, IL-17F, IL-17A/F heterodimer, and IL- 25, resulting in inhibition of inflammation and clinical symptoms associated with psoriasis. Its introduction has managed to increase the levels of efficacy, safety (improving that previously presented by the anti-IL-17 class), and survival.

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Non-neuronal TRPA1 encodes mechanical allodynia associated with neurogenic inflammation and partial nerve injury in rats.

The proalgesic transient receptor potential ankyrin 1 (TRPA1) channel, expressed by a subpopulation of primary sensory neurons, has been implicated in various pain models in mice. However, evidence in rats indicates that TRPA1 conveys nociceptive signals elicited by channel activators, but not those associated with tissue inflammation or nerve injury. Here, in rats, we explored the TRPA1 role in mechanical allodynia associated with stimulation of peptidergic primary sensory neurons (neurogenic inflammation) and moderate (partial sciatic nerve ligation, pSNL) or severe (chronic constriction injury, CCI) sciatic nerve injury.

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A comparison of health-related factors between patients diagnosed with ME/CFS and patients with a related symptom picture but no ME/CFS diagnosis: a cross-sectional exploratory study.

In chronic fatigue syndrome/myalgic encephalomyelitis (ME/CFS), the capacity for activity and participation is strongly limited. The disease definition is very broad, and considering the lack of evidence for best treatment, it is important to understand what is ME/CFS-specific in the biopsychosocial perspective in comparison with similar syndromes. The objective was to study the difference between those diagnosed with ME/CFS and those with similar symptoms but no ME/CFS diagnosis for self-perceived level of physical activity, work ability, anxiety/depression, and health-related quality of life.

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Muscle sodium content in patients with Myalgic Encephalomyelitis/Chronic Fatigue Syndrome.

Muscle fatigue and pain are key symptoms of Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS). Although the pathophysiology is not yet fully understood, there is ample evidence for hypoperfusion which may result in electrolyte imbalance and sodium overload in muscles. Therefore, the aim of this study was to assess levels of sodium content in muscles of patients with ME/CFS and to compare these to healthy controls.

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Parameters of anger as related to sensory-affective components of pain.

Comorbid with chronic pain are negative emotions, anger being particularly salient. To evaluate specific relationships between pain and anger, the present study deconstructed anger into five parameters and dichotomized pain into sensory vs. affective components. Hypotheses were (i) anger parameters would be significantly and positively correlated with affective pain more so than with sensory pain, and (ii) individual parameters would be differentially related to pain components.

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Meningeal mast cell-mediated mechanisms of cholinergic system modulation in neurogenic inflammation underlying the pathophysiology of migraine.

Growing evidence indicates that the parasympathetic system is implicated in migraine headache. However, the cholinergic mechanisms in the pathophysiology of migraine remain unclear. We investigated the effects and mechanisms of cholinergic modulation and a mast cell stabilizer cromolyn in the nitroglycerin-induced in-vivo migraine model and in-vitro hemiskull preparations in rats. Effects of cholinergic agents (acetylcholinesterase inhibitor neostigmine, or acetylcholine, and muscarinic antagonist atropine) and mast cell stabilizer cromolyn or their combinations were tested in the in-vivo and in-vitro experiments. The mechanical hyperalgesia was assessed by von-Frey hairs. Calcitonin gene-related peptide (CGRP) and C-fos levels were measured by enzyme-linked immunosorbent assay. Degranulation and count of meningeal mast cells were determined by toluidine-blue staining. Neostigmine augmented the nitroglycerin-induced mechanical hyperalgesia, trigeminal ganglion CGRP levels, brainstem CGRP and C-fos levels, as well as degranulation of mast cells in-vivo. Atropine inhibited neostigmine-induced additional increases in CGRP levels in trigeminal ganglion and brainstem while it failed to do this in the mechanical hyperalgesia, C-fos levels, and the mast cell degranulation. However, all systemic effects of neostigmine were abolished by cromolyn. The cholinergic agents or cromolyn did not alter basal release of CGRP, in-vitro, but cromolyn alleviated the CGRP-inducing effect of capsaicin while atropine failed to do it. These results ensure for a first time direct evidence that endogenous acetylcholine contributes to migraine pathology mainly by activating meningeal mast cells while muscarinic receptors are involved in CGRP release from trigeminal ganglion and brainstem, without excluding the possible role of nicotinic cholinergic receptors.

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Prevention and Management of Chronic Postsurgical Pain and Persistent Opioid Use Following Solid Organ Transplantation: Experiences From the Toronto General Hospital Transitional Pain Service.

With >700 transplant surgeries performed each year, Toronto General Hospital (TGH) is currently one of the largest adult transplant centers in North America. There is a lack of literature regarding both the identification and management of chronic postsurgical pain (CPSP) after organ transplantation. Since 2014, the TGH Transitional Pain Service (TPS) has helped manage patients who developed CPSP after solid organ transplantation (SOT), including heart, lung, liver, and renal transplants.

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Effects of Transcranial Direct Current Stimulation (t-DCS) of the Cerebellum on Pain Perception and Endogenous Pain Modulation: a Randomized, Monocentric, Double-Blind, Sham-Controlled Crossover Study.

Accumulating evidence demonstrates a role of the cerebellum in nociception. Some studies suggest that this is mediated via endogenous pain modulation. Here, we used t-DCS to test the effects of modulation of cerebellar function on nociception and endogenous pain modulation. Anodal, cathodal, and sham cerebellar t-DCS were investigated in a cross-over design in 21 healthy subjects. The nociceptive flexor (RIII) reflex, conditioning pain modulation (CPM), and offset analgesia (OA) paradigms were used to assess endogenous pain modulation. Somatosensory evoked potentials (SEPs) and pain ratings were used to assess supraspinal nociception and pain perception, respectively. No significant t-DCS effects were detected when including all t-DCS types and time points (baseline, 0, 30, 60 min post t-DCS) in the analysis. Exploratory analysis revealed an increased RIII reflex size immediately after cathodal t-DCS (compared to sham, P = 0.046, η = 0.184), in parallel with a trend for a decrease in electrical pain thresholds (P = 0.094, η = 0.134), and increased N120 SEP amplitudes 30 min after cathodal compared to anodal t-DCS (P = 0.007, η = 0.374). OA was increased after anodal compared to sham stimulation (P = 0.023, η = 0.232). Exploratory results suggested that cathodal (inhibitory) cerebellar t-DCS increased pain perception and reduced endogenous pain inhibition while anodal (excitatory) t-DCS increased endogenous pain inhibition. Results are principally compatible with activation of endogenous pain inhibition by cerebellar excitation. However, maybe due to limited t-DCS skull penetration, effects were small and unlikely to be clinically significant.

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The natural history of end-stage knee osteoarthritis: Data from the osteoarthritis initiative.

We aimed to describe the natural history leading to end-stage knee osteoarthritis (esKOA), focusing on knee symptoms, radiographic severity, and the presence of limited mobility or instability.

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Altered functional connectivity within and between resting-state networks in patients with vestibular migraine.

Previous functional magnetic resonance imaging studies have substantiated changes in multiple brain regions of functional activity in patients with vestibular migraine. However, few studies have assessed functional connectivity within and between specific brain networks in vestibular migraine.

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Trends in pharmaceutical opioid consumption in the WHO Eastern Mediterranean Region, 2010-2019.

Pharmaceutical opioid consumption has been increasing worldwide, but disparities in access to these medications exist. Few countries of the WHO Eastern Mediterranean Region have well defined pain management policies.

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Chronic pain and continuity of analgesic treatment during the COVID-19 pandemic.

Chronic pain can trigger both physical and mental health complications. During the COVID-19 pandemic, patients with chronic diseases have had reduced access to some medications.

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Dual therapy with Erenumab and onabotulinumtoxinA: no synergistic effect in chronic migraine -A retrospective cohort study.

To assess whether dual therapy with erenumab and onabotulinumtoxinA (BoNTA) was more effective than erenumab alone in chronic migraine.

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Molecular Mechanics Simulations and Experimental Investigation of the Effect of Tadalafil on Various Inflammatory Pain Mediators.

Tadalafil's exact analgesic mechanism is still unclear. The current study aimed to elucidate this mechanism in an inflammatory pain model.

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Interventions for zoster-associated pain: A retrospective study based on the clinical database.

Herpes zoster (HZ)-associated pain can lead to severe pain and reduced quality of life. Exploring effective treatment and the risk factors of zoster-associated pain has become important.

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Effluvium and alopecia associated with monoclonal calcitonin gene-related peptide antibody use.

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Chronic craniomandibular pain after craniotomy: A long-term clinical study.

Chronic craniomandibular/cervical pain and temporomandibular disorders have not been studied in patients who had a craniotomy several years previously. The aim of the current clinical work was to address these issues.

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Genome-wide DNA methylation study identifies significant epigenomic changes associated with internalized stigma in adults with non-specific chronic low back pain.

Non-specific chronic low back pain (cLBP) represents a common musculoskeletal condition with no identifiable cause. It cannot be diagnosed with conventional neuroimaging techniques such as computerized tomography (CT). The diagnostic uncertainty that characterizes non-specific cLBP can lead to stigmatizing responses from others that can become internalized Among individuals with non-specific cLBP, internalized stigma is associated with greater pain intensity and disability. Yet, no study has examined the biological mechanism linking high internalized stigma to worse outcomes in individuals with non-specific cLBP. We aimed to identify differentially methylated loci (DML), enrichment pathways, and associated network interactions among individuals with non-specific cLBP experiencing low vs. high internalized stigma. We examined DNA methylation in whole blood samples from 48 adults, ages 19-85, using reduced representation bisulfite sequencing (RRBS). After controlling for age, sex, race, and multiple testing, differentially methylated loci (DML) differed in adults with low vs. high internalized stigma by at least 10% and  < 0.01 in 3,665 CpG sites: 2,280 hypomethylated and 1,385 hypermethylated. Gene ontology (GO) analyses of the annotated genes from these sites revealed significant enrichment of 274 biological processes, 29 cellular components, and 24 molecular functions (adjusted  < 0.05). The top enriched molecular functions regulate protein binding and DNA binding of transcription factor activity. Pathway analyses indicated that many functional genomic pathways, including Hippo Signaling, Melanogenesis, and Pathways in Cancer, were enriched with differentially methylated genes. Also, there was a significant interaction between relevance pathways such as , , , and pathways. These pathways have previously been associated with neuroinflammation, neurodegeneration, and stress-related conditions. Thus, findings point to possible stress-induced DNAm changes as the link between high levels of internalized stigma and worse outcomes in adults with non-specific cLBP.

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Conservative Therapies for TMJ Closed Lock: A Randomized Controlled Trial.

Acute anterior disc displacement without reduction (ADDWoR) is characterized by permanent TMJ disc displacement, pain and functional limitations. Occlusal appliances (OA) are among the therapies of choice.

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Longitudinal changes in functional connectivity and pain-induced brain activations in patients with migraine: a functional MRI study pre- and post- treatment with Erenumab.

Migraine involves central and peripheral nervous system mechanisms. Erenumab, an anti-calcitonin gene-related peptide (CGRP) receptor monoclonal antibody with little central nervous system penetrance, is effective for migraine prevention. The objective of this study was to determine if response to erenumab is associated with alterations in brain functional connectivity and pain-induced brain activations.

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The temperature-sensitive receptors TRPV4 and TRPM8 have important roles in the pruritus of rosacea.

Certain sensations are the secondary phenotypes of rosacea and affect patients' quality of life. Transient receptor potential (TRP) channels may be involved in its occurrence. However, there is a lack of research independently discussing itch in rosacea.

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Naldemedine versus placebo in opioid-induced constipation: a meta-analysis.

Opioid-induced constipation (OIC) is a frequent adverse event among patients receiving chronic pain therapy that is requiring opioids. Naldemedine was approved by the Food and Drug Administration to treat OIC and appears to be more efficient than any other peripherally acting µ-opioid receptor antagonist. This meta-analysis aimed at assessing the available data on naldemedine in terms of efficacy.

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The pathogenesis of rheumatoid arthritis.

Significant recent progress in understanding rheumatoid arthritis (RA) pathogenesis has led to improved treatment and quality of life. The introduction of targeted-biologic and -synthetic disease modifying anti-rheumatic drugs (DMARDs) has also transformed clinical outcomes. Despite this, RA remains a life-long disease without a cure. Unmet needs include partial response and non-response to treatment in many patients, failure to achieve immune homeostasis or drug free remission, and inability to repair damaged tissues. RA is now recognized as the end of a multi-year prodromal phase in which systemic immune dysregulation, likely beginning in mucosal surfaces, is followed by a symptomatic clinical phase. Inflammation and immune reactivity are primarily localized to the synovium leading to pain and articular damage, but is also associated with a broader series of comorbidities. Here, we review recently described immunologic mechanisms that drive breach of tolerance, chronic synovitis, and remission.

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Huc-MSCs-derived exosomes attenuate neuropathic pain by inhibiting activation of the TLR2/MyD88/NF-κB signaling pathway in the spinal microglia by targeting Rsad2.

Mesenchymal stem cells (MSCs)-derived exosomes have shown promise as a cell-free therapeutic strategy for neuropathic pain. This study was conducted to explore the potential mechanisms underlying the analgesic effects of MSC-derived exosomes in treating neuropathic pain.

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CBD Retailers in NC Promote CBD Online to Treat Pain Violating FDA Rules About Medical Claims and Offer Low-CBD/High-Price Products.

Cannabidiol (CBD) products are available nearly nationwide in the US and can coexist with medical or recreational programs. North Carolina (NC) is an example of a state with a program dedicated to integrating hemp cultivation and medicinal CBD exclusively, containing a multitude of retailers selling it as a primary product. The Food and Drug Administration (FDA) mandates that non-FDA approved CBD products cannot be marketed using medical or health-related claims and has sent warning letters to retailers violating these terms. We aim to characterize the online content of the NC CBD market by analyzing retailers' websites to determine whether hemp/CBD shops comply with FDA regulations in terms of medical claims and analyze the claimed CBD content and price of products offered online.

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Racial Differences in 25-Hydroxy Vitamin D and Self-Reported Pain Severity in a Sample of Individuals Living with Non-Specific Chronic Low Back Pain.

Considerable evidence suggests that there are significant ethnic/racial differences in the experience of pain among individuals suffering from chronic musculoskeletal conditions. Additionally, low levels of vitamin D have been associated with pain severity. Further, vitamin D deficiency is more prevalent in Non-Hispanic Black (NHB) individuals compared to Non-Hispanic Whites (NHW).

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Clinical Practice Guidelines on Interventional Management of Low Back Pain: A Synthesis of Recommendations.

To summarize the recommendations on the interventional management of subacute and chronic non-radicular low back pain (LBP) from the 21 quality-appraised CPGs identified in the previously published paper: "Quality of Clinical Practice Guidelines on Interventional Management of Low Back Pain: A Systematic Review". By disseminating this information, we aim to facilitate the implementation of these recommendations into clinical practice.

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Modulation of colonic function in irritable bowel syndrome rats by electroacupuncture at ST25 and the neurobiological links between ST25 and the colon.

Irritable bowel syndrome (IBS) is a chronic functional gastrointestinal disease characterized by abdominal pain and defecation disorders. Acupuncture therapy positively affects IBS, with ST25 being the main point. However, ST25 has mostly been used in conjunction with other acupoints. This study aimed to observe the therapeutic effect of electroacupuncture at ST25 alone in IBS and the neurobiological mechanism of ST25 associated with the colon. First, we observed the effect of electroacupuncture at ST25 on the visceral pain threshold and slow-wave discharge of the colon in IBS model rats. Second, we explored the neurobiological mechanism of ST25 associated with the colon using a neural tracer technique. The results showed that (1) electroacupuncture at ST25 alone can alleviate visceral hypersensitivity and restore normal slow-wave frequency and rhythm of the colon in IBS rats; (2) there is a close neuroanatomical connection between ST25 and the colon, i.e., in the dorsal root ganglion (DRG), ST25 is similar in innervation to the colon, mainly in the T8-L1 segment, while the presence of double-labeled positive neurons is present in a part of the DRG; retrogradely labeled motor neurons associated with ST25 were observed in the anterior horn of the spinal cord, and retrogradely labeled sympathetic postganglionic neurons associated with ST25 were observed in the sympathetic nerve chain. These findings suggested that the DRGs and the dorsal horn of the spinal cord are important targets for electroacupuncture at ST25 to reduce visceral hypersensitivity in IBS rats. The sympathetic ganglia may be an important site for ST25 to regulate intestinal motility. The neurobiological mechanism of ST25 action in IBS rats should be further investigated in the future by combining related techniques, such as pseudorabies virus, optogenetics, calcium imaging, and electrophysiology.

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Physical therapist-delivered acceptance and commitment therapy and exercise for older outpatients with knee osteoarthritis: a pilot randomized controlled trial.

[Purpose] In this pilot study, we investigated the effectiveness of physical therapist-delivered acceptance and commitment therapy in older outpatients with knee osteoarthritis and chronic pain. [Participants and Methods] This single-center, open-label, parallel-group pilot randomized controlled trial included 30 patients assigned to the physical therapist-delivered acceptance and commitment therapy group (n=15) and the usual care physical therapy-only group (n=15). Both treatments were administered once a week for 8 weeks. Evaluation was performed 4 weeks before intervention, pre-intervention, post-intervention, and 4 weeks after intervention. The primary outcome was diagnosis of a physical disability, and secondary outcomes included psychological inflexibility, pain intensity, anxiety, depression, physical function, and objectively measured physical activity. [Results] Physical therapist-delivered acceptance and commitment therapy had a limited effect on physical disability, although we observed a favorable tendency. With regard to secondary outcomes, physical therapist-delivered acceptance and commitment therapy did not show significant effects. Notably, 15 patients withdrew from this study and 6 were diagnosed with coronavirus disease. [Conclusion] Physical therapist-delivered acceptance and commitment therapy did not appear to show significant effects in the present study. It is necessary to correct these issues in this study, and future studies are warranted to investigate the effects of this therapy.

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The differential contribution of spinal α- and α-adrenoceptors in tonic and acute evoked nociception in the rat.

Spinal α-adrenoceptor induces analgesia by neuronal inhibition of primary afferent fibers. This family receptor coupled to G proteins can be subdivided into three functional subtypes: α, α and α-adrenoceptors, and current evidence on spinal analgesia supports the relevance of α and seems to exclude the role of α, but the functional contribution of α-adrenoceptors remains elusive. The present study was designed to pharmacologically dissect the contribution of spinal α-adrenoceptor subtypes modulating tonic or acute peripheral nociception. Using male Wistar rats, we analyzed the effect of spinal clonidine (a non-selective ααα-adrenoceptor agonist) and/or selective subtype α-adrenoceptor antagonists on: 1) tonic nociception induced by subcutaneous formalin (flinching behavior) or 2) acute nociception induced by peripheral electrical stimulus in extracellular recordings of spinal dorsal horn second-order wide dynamic range (WDR) neurons. Clonidine inhibited the nocifensive behavior induced by formalin, an effect blocked by BRL 44408 (α-adrenoceptor antagonist) but not by imiloxan (α-adrenoceptor antagonist) or JP 1302 (α-adrenoceptor antagonist). Similarly, spinal BRL 44408 reversed the clonidine-induced inhibition of nociceptive WDR activity. Interestingly, spinal JP 1302 produced behavioral antinociception (an effect blocked by bicuculline, a preferent GABA channel blocker), but no correlation was found with the electrophysiological experiments. These data imply that, at the spinal level, 1) presynaptic α-adrenoceptor activation produces antinociception during acute or tonic nociceptive stimuli; and 2) under tonic nociceptive (inflammatory) input, spinal α-adrenoceptors are pronociceptive, probably by the inactivation of GABAergic transmission. This result supports a differential role of α and α-adrenoceptors modulating nociception.

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Low-dose naloxone for prophylaxis of sufentanil-induced choking and postoperative nausea and vomiting.

Sufentanil, a potent opioid, serves as the first option for perioperative analgesia owing to its analgesic effect, long duration and stable hemodynamics, whereas its side effects frequently blunt its application. The intravenous (IV) injection of sufentanil during anesthesia induction has high incidence of choking or bucking reaction, which is defined as sufentanil-induced cough (SIC). Moreover, postoperative nausea and vomiting (PONV) is a common and stressful complication, which is also related to the usage of opioid. High incidence of PONV is reported in the patients with SIC. Hence, we sought to determine whether naloxone, an opioid antagonist, at low dose would decrease the incidences of SIC and PONV. 216 female patients undergoing gynecological laparoscopic operation (<2 h) under general anesthesia were recruited in this study, and randomly assigned into two groups: Group N (patients receiving naloxone and Group C (patients receiving vehicle). Sufentanil (0.5 μg/kg within 5 s) was given in anesthesia induction, and low-dose naloxone (1.25 μg/kg) or identical vehicle was initially injected 5 min prior to induction, with the incidence and severity of SIC estimated. Subsequently, naloxone or vehicle was continuously infused at the rate of 0.5 μg/kg/h in the initiation of operation until the end of the operation, and the transverse abdominal fascia block (TAP) was performed for postoperative analgesia. The PONV profiles such as incidence and the severity, grading, and the frequencies of antiemetic usage within 24 h were evaluated, with VAS scores and remedial measures for analgesia during the first 24 h postoperatively were recorded. Our results revealed that one bolus of low-dose naloxone prior to the induction significantly mitigated the incidence of SIC, and intraoperative continuous infusion of low-dose naloxone reduced the incidence and the severity of PONV, so that the postoperative VAS scores and further remedial analgesia were not altered. These results not only provide clinical solutions for prophylaxis of SIC and PONV, but also suggests that opioids may act as a key role in both SIC and PONV, whereas opioid antagonist may hit two tasks with one stone. Moreover, further investigations are required to address the underlying mechanism of SIC and PONV. : [www.chictr.org.cn], identifier [ChiCTR2200064865].

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Task-dependent plasticity in distributed neural circuits after transcranial direct current stimulation of the human motor cortex: A proof-of-concept study.

The ability of non-invasive brain stimulation to induce neuroplasticity and cause long-lasting functional changes is of considerable interest for the reversal of chronic pain and disability. Stimulation of the primary motor cortex (M1) has provided some of the most encouraging after-effects for therapeutic purposes, but little is known about its underlying mechanisms. In this study we combined transcranial Direct Current Stimulation (tDCS) and fMRI to measure changes in task-specific activity and interregional functional connectivity between M1 and the whole brain. Using a randomized counterbalanced sham-controlled design, we applied anodal and cathodal tDCS stimulation over the left M1. In agreement with previous studies, we demonstrate that tDCS applied to the target region induces task-specific facilitation of local brain activity after anodal tDCS, with the stimulation effects having a negative relationship to the resting motor threshold. Beyond the local effects, tDCS also induced changes in multiple downstream regions distinct from the motor system that may be important for therapeutic efficacy, including the operculo-insular and cingulate cortex. These results offer opportunities to improve outcomes of tDCS for the individual patient based on the degree of presumed neuroplasticity. Further research is still warranted to address the optimal stimulation targets and parameters for those with disease-specific symptoms of chronic pain.

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The gut microbiota and endometriosis: From pathogenesis to diagnosis and treatment.

Endometriosis is a common gynecological disease, that often leads to pain and infertility. At present, the specific pathogenesis of endometriosis has not been clarified, but it may be closely related to an imbalance of sex hormones in the body, ectopic hyperplasia stimulated by immune inflammation, and invasion and escape based on tumor characteristics. Gut microbiota is associated with many inflammatory diseases. With the further study of the gut microbiota, people are paying increasing attention to its relationship with endometriosis. Studies have shown that there is an association between the gut microbiota and endometriosis. The specific ways and mechanisms by which the gut microbiota participates in endometriosis may involve estrogen, immune inflammation, and tumor characteristics, among others. Therefore, in the future, regulating gut microbiota disorders in various ways can help in the treatment of endometriosis patients. This study reviewed the research on the gut microbiota and endometriosis in order to provide ideas for clinical diagnosis and treatment.

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Wnt signaling pathway inhibitors, sclerostin and DKK-1, correlate with pain and bone pathology in patients with Gaucher disease.

Patients with Gaucher disease (GD) have progressive bone involvement that clinically presents with debilitating bone pain, structural bone changes, bone marrow infiltration (BMI), Erlenmeyer (EM) flask deformity, and osteoporosis. Pain is referred by the majority of GD patients and continues to persist despite the type of therapy. The pain in GD is described as chronic deep penetrating pain; however, sometimes, patients experience severe acute pain. The source of bone pain is mainly debated as nociceptive pain secondary to bone pathology or neuropathic or inflammatory origins. Osteocytes constitute a significant source of secreted molecules that coordinate bone remodeling. Osteocyte markers, sclerostin (SOST) and Dickkopf-1 (DKK-1), inactivate the canonical Wnt signaling pathway and lead to the inhibition of bone formation. Thus, circulated sclerostin and DKK-1 are potential biomarkers of skeletal abnormalities. This study aimed to assess the circulating levels of sclerostin and DKK-1 in patients with GD and their correlation with clinical bone pathology parameters: pain, bone mineral density (BMD), and EM deformity. Thirty-nine patients with GD were classified into cohorts based on the presence and severity of bone manifestations. The serum levels of sclerostin and DKK-1 were quantified by enzyme-linked immunosorbent assays. The highest level of sclerostin was measured in GD patients with pain, BMI, and EM deformity. The multiparameter analysis demonstrated that 95% of GD patients with pain, BMI, and EM deformity had increased levels of sclerostin. The majority of patients with elevated sclerostin also have osteopenia or osteoporosis. Moreover, circulating sclerostin level increase with age, and GD patients have elevated sclerostin levels when compared with healthy control from the same age group. Pearson's linear correlation analysis showed a positive correlation between serum DKK-1 and sclerostin in healthy controls and GD patients with normal bone mineral density. However, the balance between sclerostin and DKK-1 waned in GD patients with osteopenia or osteoporosis. In conclusion, the osteocyte marker, sclerostin, when elevated, is associated with bone pain, BMI, and EM flask deformity in GD patients. The altered sclerostin/DKK-1 ratio correlates with the reduction of bone mineral density. These data confirm that the Wnt signaling pathway plays a role in GD-associated bone disease. Sclerostin and bone pain could be used as biomarkers to assess patients with a high risk of BMI and EM flask deformities.

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Persistent expression of NLRP3 in spinal microglia promotes development of lumbar disc degeneration.

Activated microglia play a critical role in the development of lumbar disc degeneration (LDD), which is a severe disease that causes neuropathic pain in affected people. Interleukin 1β (IL-1β) is a proinflammatory cytokine produced and secreted by activated microglia to induce the inflammation and the subsequent degradation of the disease discs. Recent findings suggest that activation of IL-1β in cells usually requires the involvement of NACHT, LRR and PYD domains-containing protein 3 (NLRP3)-induced formation of inflammasome. However, the importance of NLRP3 in spinal microglia in LDD is not known and thus addressed in the current study.

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Novel therapeutic approach to slow down the inflammatory cascade in acute/subacute spinal cord injury: Early immune therapy with lipopolysaccharide enhanced neuroprotective effect of combinational therapy of granulocyte colony-stimulating factor and bone-

Bone-marrow mesenchymal stem cells (BM-MSCs) have not yet proven any significant therapeutic efficacy in spinal cord injury (SCI) clinical trials, due to the hostile microenvironment of the injured spinal cord at the acute phase. This study aims to modulate the inflammatory milieu by lipopolysaccharide (LPS) and granulocyte colony-stimulating factor (G-CSF) to improve the BM-MSCs therapy. For this purpose, we determined the optimum injection time and sub-toxic dosage of LPS following a T10 contusion injury. Medium-dose LPS administration may result in a local anti-inflammatory beneficial role. This regulatory role is associated with an increase in NF-200-positive cells, significant tissue sparing, and improvement in functional recovery compared to the SCI control group. The second aim was to examine the potential ability of LPS and LPS + G-CSF combination therapy to modulate the lesion site before BM-MSC (1 × 105 cells) intra-spinal injection. Our results demonstrated combination therapy increased potency to enhance the anti-inflammatory response (IL-10 and Arg-1) and decrease inflammatory markers (TNF-α and CD86) and caspase-3 compared to BM-MSC monotherapy. Histological analysis revealed that combination groups displayed better structural remodeling than BM-MSC monotherapy. In addition, Basso-Beattie-Bresnahan (BBB) scores show an increase in motor recovery in all treatment groups. Moreover, drug therapy shows faster recovery than BM-MSC monotherapy. Our results suggest that a sub-toxic dose of LPS provides neuroprotection to SCI and can promote the beneficial effect of BM-MSC in SCI. These findings suggest that a combination of LPS or LPS + G-CSF prior BM-MSC transplantation is a promising approach for optimizing BM-MSC-based strategies to treat SCI. However, because of the lack of some methodological limitations to examine the survival rate and ultimate fate of transplanted BM-MSCs followed by LPS administration in this study, further research needs to be done in this area. The presence of only one-time point for evaluating the inflammatory response (1 week) after SCI can be considered as one of the limitations of this study. We believed that the inclusion of additional time points would provide more information about the effect of our combination therapy on the microglia/macrophage polarization dynamic at the injured spinal cord.

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Association between migraine and cardiovascular disease: A cross-sectional study.

Cardiovascular disease (CVD) poses a tremendous threat to global health, giving rise to exceedingly high morbidity and mortality among patients. A migraine is a common neurological disorder characterized by recurrent attacks of severe headache, while its cardiovascular burden remains unclear. Therefore, this study aims to investigate whether migraine is associated with CVD.

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Efficacy of repetitive transcranial magnetic stimulation on chronic migraine: A meta-analysis.

Migraine is a neurovascular disorder that affects the quality of life of more than 1 billion people worldwide. Repetitive transcranial magnetic stimulation (rTMS) is a neuromodulation tool that uses pulsed magnetic fields to modulate the cerebral cortex. This meta-analysis ascertained the therapeutic or preventive effect of rTMS on chronic migraine.

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Altered Structural and Functional Abnormalities of Hippocampus in Classical Trigeminal Neuralgia: A Combination of DTI and fMRI Study.

Diffusion tensor imaging (DTI) and resting-state functional magnetic resonance imaging (rs-fMRI) were applied to speculate the altered structural and functional abnormalities within the hippocampus in classical trigeminal neuralgia (CTN) patients by detecting the alteration of apparent diffusion coefficient (ADC), fractional anisotropy (FA), and regional homogeneity (ReHo). . Multimodal MRI dataset (DTI and fMRI) and clinical indices (pain and neuropsychological scores) were collected in 27 CTN patients and 27 age- and gender-matched healthy controls (HC). Two independent-sample -tests were performed to compare the ADC, FA, and ReHo values in hippocampus areas between CTN patients and HC. Correlation analyses were applied between all the DTI and fMRI parameters within the hippocampus and the VAS (visual analog scale), MoCA (Montreal cognitive assessment), and CDR (clinical dementia rating) scores.

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Systematic review and meta-analysis on the association between chronic low back pain and cognitive function.

This study aimed to identify and assess the evidence on the association between idiopathic chronic low back pain (LBP) and cognitive function in individuals with LBP. A secondary aim was to explore whether changes in cognitive function are associated with pain characteristics and psychological factors (e.g., catastrophizing and fear of movement). Eleven studies were included in this systematic review and four meta-analyses were conducted. Low to very low quality evidence suggests impaired cognitive function in individuals with LBP compared to asymptomatic controls for problem solving ((k=5; d= 0.33; CI=0.16-0.50; z=3.85 p=0.0001), speed of information processing (k=5; d= 0.44; CI=0.22-0.65; z=4.02 p<0.0001), working memory (k=6; d= 0.50; CI=0.34-0.66; z=6.09 p<0.0001) and delayed memory (k=3; d= 0.34; CI=0.07-0.6, z=2.49 p=0.02). The association between LBP intensity and psychological factors and cognitive function was inconclusive. More studies are needed to explore these associations and improve evidence in this field. The results of this study suggest that cognitive aspects should be considered during the rehabilitation process of patients with LBP, and raise further questions, including whether individuals with LBP are at a greater risk of developing dementia or whether targeting cognitive function will increase the probability of success of LBP treatment. These questions should, also, be considered in future studies.

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Relationship between the dose titration and adherence of mirogabalin in patients with peripheral neuropathic pain depending on renal function: a nationwide electronic medical record database study.

Mirogabalin has been attracting attention for treating peripheral neuropathic pain. The package insert recommends that mirogabalin should be titrated depending on renal function. Here, we investigated the relationship between dose titration patterns and adherence, and persistence of mirogabalin treatment.

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Analgesic effects of main indole alkaloid of kratom, mitragynine in acute pain animal model.

Mitragynine exerts its analgesic effect mainly via opioid receptors activation. Additionally, the effect may be mediated via mitragynine's anti-inflammatory property and non-opioid receptor pain pathways, namely through the TRPV1 receptor. No studies identify hitherto, hence, the current study aimed to investigate the mitragynine's analgesic effect via the anti-inflammatory property, non-opioid receptor (TRPV1) and the effective dose (ED) to alleviate pain. Male and female Sprague Dawley rats were pre-treated intraperitoneally with either mitragynine (1, 5, 10, 13, 15 or 30 mg/kg), vehicle, or indomethacin (1 mg/kg) 30 min before inducing inflammatory pain using acetic acid. The writhes and pain-related withdrawal behaviour occurrence were counted within a 1-h duration. Percentage of writhes inhibition, pain-related withdrawal behaviour aggregate, ED50 and ED95 were determined. The body temperature was recorded and TRPV1 expression in the rats' brains was measured. Mitragynine (except 1 mg/kg) significantly reduced the number of writhes compared with the vehicle administered group. Mitragynine (30 mg/kg) demonstrated 99.5% inhibition of writhing behaviour and low withdrawal behaviour score compared with vehicle and indomethacin and successfully blocked the hypothermia induced by acetic acid. The overall ED50 and ED95 values of mitragynine were 3.62 and 20.84 mg/kg, respectively. The percentage of writhing inhibition and withdrawal behaviour were similar in both genders. Mitragynine (15 and 30 mg/kg) significantly reduced the TRPV1 expression in the brain of the rats. Mitragynine alleviated pain-like behaviour and showed analgesic effects via anti-inflammatory and non-opioid receptor pathways. The findings also suggest that mitragynine might regulate some physiological functions of the rat.

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TRPV4 activation increases the expression of CD207 (Langerin) of monocyte-derived Langerhans cells, without affecting their maturation.

Langerhans cells (LCs) are the sole professional antigen-presenting cell normally found in the human epidermal compartment. Research into their physiological role is hindered by the fact that they are invariably activated during isolation from the skin. To overcome this challenge, we turned to a monocyte-derived LC model (moLC), which we characterized with RNASeq, and compared the transcriptome of moLCs to donor-matched immature dendritic cells. We found that moLCs express markers characteristic of LC2 cells, as well as transient receptor potential vanilloid 4 (TRPV4). TRPV4 is especially important in skin, as it has been linked to conservation of the skin barrier, immunological responses as well as acute and chronic itch, but we know little about its function on LCs. Our results show that TRPV4 activation increased the expression of Langerin and led to increased intracellular calcium concentration in moLCs. Regarding the functionality of moLCs, we found that TRPV4 agonism had a mitigating effect on their inflammatory responses, since it decreased their cytokine production, and T cell activating capability. As TRPV4 has emerged as a potential therapeutic target in dermatological conditions, it is important to highlight LCs as a novel target of these therapies.

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How Does Changing the Time to Surgery Affect the Recurrence of Post-Traumatic Trigeminal Neuropathic Pain.

The recurrence of post-traumatic trigeminal neuropathic pain (PTTNp) following peripheral microneurosurgery continues to be poorly understood. The objective of this study was to determine if the time from injury to surgery of the trigeminal nerve in patients with PTTNp affected the recurrence of PTTNp following surgery.

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Possible synergic action of non-steroidal anti-inflammatory drugs and glucosamine sulfate for the treatment of knee osteoarthritis: a scoping review.

Several studies have reported that glucosamine sulfate (GS) can improve knee osteoarthritis (OA) symptomatology. In parallel, the disease-modifying effects of non-steroidal anti-inflammatory drugs (NSAIDs) in knee OA have also been investigated. However, limited literature has reported the combined effect of GS and NSAIDs. The aim of this scoping review is to describe the scope and volume of the literature investigating the potential benefits and synergistic effect of a combination of GS and NSAIDs in patients with knee OA.

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Transglutaminase 2 inhibitors attenuate osteoarthritic degeneration of TMJ-osteoarthritis by suppressing NF-κB activation.

The temporomandibular joint osteoarthritis (TMJ-OA) is characterized by progressive cartilage degradation, subchondral bone erosion, and chronic pain, leading to articular damage and chewing dysfunction. Studies have shown that interleukin-1β (IL-1β) plays a critical role in the development of TMJ-OA. Transglutaminase 2 (TG2) has been identified as a marker of chondrocyte hypertrophy and IL-1β was able to increase TG2 expression in chondrocytes. Therefore, the aim of this study was to explore the ability of TG2 inhibitors to suppress TMJ-OA progression.

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[Support of opioid rotation using online apps : Evaluation of applicability and comparison to the LONTS guidelines].

Opioid rotation can be indicated due to drug side effects, drug interactions or inadequate effect of treatment with opioids. For the determination of the oral morphine equivalence, a practice tool has been published with the long-term use of opioids in chronic nontumor-related pain (LONTS) guidelines. In contrast, several apps are available that have not yet been evaluated.

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[Transcranial alternating current stimulation to modulate oscillations in pain disorders].

Chronic pain is a common health problem, for which the treatment is complex and challenging. Non-invasive brain stimulation techniques, specifically transcranial alternating current stimulation (tACS), show promise as a well-tolerated new therapeutic modality with few side effects. This is supported by growing evidence of an association between altered neuronal oscillations and chronic pain. However, to date, only a handful of studies with variable methodology have evaluated tACS for potential applicability to patients with chronic pain.

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TRPV3 and Itch: The Role of TRPV3 in Chronic Pruritus according to Clinical and Experimental Evidence.

Itching is a sensory phenomenon characterized by an unpleasant sensation that makes you want to scratch the skin, and chronic itching diminishes the quality of life. In recent studies, multiple transient receptor potential (TRP) channels present in keratinocytes or nerve endings have been shown to engage in the propagation of itch signals in chronic dermatological or pruritic conditions, such as atopic dermatitis (AD) and psoriasis (PS). TRPV3, a member of the TRP family, is highly expressed in the epidermal keratinocytes. Normal TRPV3 signaling is essential for maintaining epidermal barrier homeostasis. In recent decades, many studies have suggested that TRPV3 contributes to detecting pruritus signals. Gain-of-function mutations in TRPV3 in mice and humans are characterized by severe itching, hyperkeratosis, and elevated total IgE levels. These studies suggest that TRPV3 is an important channel for skin itching. Preclinical studies have provided evidence to support the development of TRPV3 antagonists for treating inflammatory skin conditions, itchiness, and pain. This review explores the role of TRPV3 in chronic pruritus, collating clinical and experimental evidence. We also discuss underlying cellular and molecular mechanisms and explore the potential of TRPV3 antagonists as therapeutic agents.

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Effects of Different Opioid Drugs on Oxidative Status and Proteasome Activity in SH-SY5Y Cells.

Opioids are the most effective drugs used for the management of moderate to severe pain; however, their chronic use is often associated with numerous adverse effects. Some results indicate the involvement of oxidative stress as well as of proteasome function in the development of some opioid-related side effects including analgesic tolerance, opioid-induced hyperalgesia (OIH) and dependence. Based on the evidence, this study investigated the impact of morphine, buprenorphine or tapentadol on intracellular reactive oxygen species levels (ROS), superoxide dismutase activity/gene expression, as well as β2 and β5 subunit proteasome activity/biosynthesis in SH-SY5Y cells. Results showed that tested opioids differently altered ROS production and SOD activity/biosynthesis. Indeed, the increase in ROS production and the reduction in SOD function elicited by morphine were not shared by the other opioids. Moreover, tested drugs produced distinct changes in β2(trypsin-like) and β5(chymotrypsin-like) proteasome activity and biosynthesis. In fact, while prolonged morphine exposure significantly increased the proteolytic activity of both subunits and β5 mRNA levels, buprenorphine and tapentadol either reduced or did not alter these parameters. These results, showing different actions of the selected opioid drugs on the investigated parameters, suggest that a low µ receptor intrinsic efficacy could be related to a smaller oxidative stress and proteasome activation and could be useful to shed more light on the role of the investigated cellular processes in the occurrence of these opioid drug side effects.

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Roles of Resolvins in Chronic Inflammatory Response.

An inflammatory response is beneficial to the organism, while an excessive uncontrolled inflammatory response can lead to the nonspecific killing of tissue cells. Therefore, promoting the resolution of inflammation is an important mechanism for protecting an organism suffering from chronic inflammatory diseases. Resolvins are a series of endogenous lipid mediums and have the functions of inhibiting a leukocyte infiltration, increasing macrophagocyte phagocytosis, regulating cytokines, and alleviating inflammatory pain. By promoting the inflammation resolution, resolvins play an irreplaceable role throughout the pathological process of some joint inflammation, neuroinflammation, vascular inflammation, and tissue inflammation. Although a large number of experiments have been conducted to study different subtypes of resolvins in different directions, the differences in the action targets between the different subtypes are rarely compared. Hence, this paper reviews the generation of resolvins, the characteristics of resolvins, and the actions of resolvins under a chronic inflammatory response and clinical translation of resolvins for the treatment of chronic inflammatory diseases.

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Reversal of Peripheral Neuropathic Pain by the Small-Molecule Natural Product Narirutin via Block of Na1.7 Voltage-Gated Sodium Channel.

Neuropathic pain is a refractory chronic disease affecting millions of people worldwide. Given that present painkillers have poor efficacy or severe side effects, developing novel analgesics is badly needed. The multiplex structure of active ingredients isolated from natural products provides a new source for phytochemical compound synthesis. Here, we identified a natural product, Narirutin, a flavonoid compound isolated from the , showing antinociceptive effects in rodent models of neuropathic pain. Using calcium imaging, whole-cell electrophysiology, western blotting, and immunofluorescence, we uncovered a molecular target for Narirutin's antinociceptive actions. We found that Narirutin (i) inhibits Veratridine-triggered nociceptor activities in L4-L6 rat dorsal root ganglion (DRG) neurons, (ii) blocks voltage-gated sodium (Na) channels subtype 1.7 in both small-diameter DRG nociceptive neurons and human embryonic kidney (HEK) 293 cell line, (iii) does not affect tetrodotoxin-resistant (TTX-R) Na channels, and (iv) blunts the upregulation of Na1.7 in calcitonin gene-related peptide (CGRP)-labeled DRG sensory neurons after spared nerve injury (SNI) surgery. Identifying Na1.7 as a molecular target of Narirutin may further clarify the analgesic mechanism of natural flavonoid compounds and provide an optimal idea to produce novel selective and efficient analgesic drugs.

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Intraarticular Injections of Mesenchymal Stem Cells in Knee Osteoarthritis: A Review of Their Current Molecular Mechanisms of Action and Their Efficacy.

More than 10% of the world's population suffers from osteoarthritis (OA) of the knee, with a lifetime risk of 45%. Current treatments for knee OA pain are as follows: weight control; oral pharmacological treatment (non-steroidal anti-inflammatory drugs, paracetamol, opioids); mechanical aids (crutches, walkers, braces, orthotics); therapeutic physical exercise; and intraarticular injections of corticosteroids, hyaluronic acid, and platelet-rich plasma (PRP). The problem is that such treatments usually relieve joint pain for only a short period of time. With respect to intraarticular injections, corticosteroids relieve pain for several weeks, while hyaluronic acid and PRP relieve pain for several months. When the above treatments fail to control knee pain, total knee arthroplasty (TKA) is usually indicated; however, although a very effective surgical technique, it can be associated with medical and postoperative (surgery-related) complications. Therefore, it seems essential to look for safe and effective alternative treatments to TKA. Recently, there has been much research on intraarticular injections of mesenchymal stem cells (MSCs) for the management of OA of the knee joint. This article reviews the latest information on the molecular mechanisms of action of MSCs and their potential therapeutic benefit in clinical practice in patients with painful knee OA. Although most recent publications claim that intraarticular injections of MSCs relieve joint pain in the short term, their efficacy remains controversial given that the existing scientific information on MSCs is indecisive. Before recommending intraarticular MSCs injections routinely in patients with painful knee OA, more studies comparing MSCs with placebo are needed. Furthermore, a standard protocol for intraarticular injections of MSCs in knee OA is needed.

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Sex Differences in Neuropathy: The Paradigmatic Case of MetFormin.

As a widely prescribed anti-diabetic drug, metformin has been receiving novel attention for its analgesic potential. In the study of the complex etiology of neuropathic pain (NeP), male and female individuals exhibit quite different responses characterized by higher pain sensitivity and greater NeP incidence in women. This "gender gap" in our knowledge of sex differences in pain processing strongly limits the sex-oriented treatment of patients suffering from NeP. Besides, the current investigation of the analgesic potential of metformin has not addressed the "gender gap" problem. Hence, this study focuses on metformin and sex-dependent analgesia in a murine model of NeP induced by chronic constriction injury of the sciatic nerve. We investigated sexual dimorphism in signaling pathways involved by 7 days of metformin administration, such as changes in AMP-activated protein kinase and the positive regulation of autophagy machinery, discovering that metformin affected in a sexually dimorphic manner the immunological and inflammatory response to nerve lesion. These effects were complemented by morphological and adaptive changes occurring after peripheral nerve injury. Altogether these data can contribute to explaining a number of potential mechanisms responsible for the complete recovery from NeP found in male mice, as opposed to the failure of long-lasting recovery in female animals.

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Associations between Fatty Acid Intake and Tension-Type Headache: A Cross-Sectional Study.

Patients with tension-type headache (TTH) are characterized by recurrent pain that can become disabling. Identifying the dietary triggers of headaches has led to defining dietary strategies to prevent this disease. In fact, excessive dietary intake of Omega-6 (ω-6) fatty acids, or an ω-6: ω3 ≥ 5 ratio, typical of Western diets, has been associated with a higher prevalence of headaches. The objectives of the present study were to compare dietary fatty acid intake between participants with and without chronic TTH and to investigate the association between dietary fatty acid intake, pain characteristics, and quality of life in patients with chronic TTH.

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Pharmacological Interventions for Opioid-Induced Hyperalgesia: A Scoping Review of Preclinical Trials.

Opioid analgesics are the most effective pharmacological agents for moderate and severe pain. However, opioid use has several limitations such as opioid-induced hyperalgesia (OIH), which refers to the increased pain sensitivity that occurs once analgesia wears off after opioid administration. Several pharmacological interventions have been suggested for OIH, but the current literature does not provide guidelines on which interventions are the most effective and whether they differ depending on the opioid that induces hyperalgesia. This scoping review aimed to identify and describe all the preclinical trials investigating pharmacological interventions for OIH caused by remifentanil, fentanyl, or morphine as the first step towards evaluating whether the most effective OIH interventions are different for different opioids.

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Randomized Feasibility Pilot Trial of Adding a New Three-Dimensional Adjustable Posture-Corrective Orthotic to a Multi-Modal Program for the Treatment of Nonspecific Neck Pain.

The aim of this study was to investigate the feasibility and effect of a multimodal program for the management of chronic nonspecific neck pain CNSNP with the addition of a 3D adjustable posture corrective orthotic (PCO), with a focus on patient recruitment and retention. This report describes a prospective, randomized controlled pilot study with twenty-four participants with CNSNP and definite 3D postural deviations who were randomly assigned to control and study groups. Both groups received the same multimodal program; additionally, the study group received a 3D PCO to perform mirror image therapy for 20-30 min while the patient was walking on a treadmill 2-3 times per week for 10 weeks. Primary outcomes included feasibility, recruitment, adherence, safety, and sample size calculation. Secondary outcomes included neck pain intensity by numeric pain rating scale (NPRS), neck disability index (NDI), active cervical ROM, and 3D posture parameters of the head in relation to the thoracic region. Measures were assessed at baseline and after 10 weeks of intervention. Overall, 54 participants were screened for eligibility, and 24 (100%) were enrolled for study participation. Three participants (12.5%) were lost to reassessment before finishing 10 weeks of treatment. The between-group mean differences in change scores indicated greater improvements in the study group receiving the new PCO intervention. Using an effect size of 0.797, α &gt; 0.05, β = 80% between-group improvements for NDI identified that 42 participants were required for a full-scale RCT. This pilot study demonstrated the feasibility of recruitment, compliance, and safety for the treatment of CNSNP using a 3D PCO to a multimodal program to positively affect CNSNP management.

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Opioid Free Anesthesia in Thoracic Surgery: A Systematic Review and Meta Analysis.

Recent studies showed that balanced opioid-free anesthesia is feasible and desirable in several surgical settings. However, in thoracic surgery, scientific evidence is still lacking. Thus, we conducted the first systematic review and meta-analysis of opioid-free anesthesia in this field.

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Time Trends and Sex Differences in the Association between Diabetes and Chronic Neck Pain, Chronic Low Back Pain, and Migraine. Analysis of Population-Based National Surveys in Spain (2014-2020).

(1) Background: To assess the time trend in the prevalence of chronic neck pain (CNP), chronic low back pain (CLBP), and migraine or frequent headache (MFH) among people with diabetes in Spain from 2014 to 2020, this study identified sex differences and compared the prevalence of these pain sites between people with diabetes and age-sex-matched non-diabetic subjects. (2) Methods: The study design included a cross-sectional and a case-control study. The data were obtained from the European Health Interview Surveys for Spain conducted in 2014 and 2020. The presence of diabetes, CNP, CLBP, and MFH was self-reported. Study covariates included sociodemographic characteristics, comorbidities, lifestyles, and pain-related variables. (3) Results: Among people with diabetes, the prevalence of CNP, CLBP, and MFH did not improve from 2014 to 2020. Women with diabetes had a significantly higher prevalence of all the pain sites analyzed than men with diabetes. After matching by sex and age, the prevalence of CNP (26.0% vs. 21.1%; &lt; 0.001), CLBP (31.2% vs. 25.0%; &lt; 0.001), and MFH (7.7% vs. 6.5%; = 0.028) was higher for people with diabetes than for those without diabetes. Self-reported mental disease was independently associated with reporting the three pain sites analyzed in people with diabetes. (4) Conclusions: The prevalence of CNP, CLBP, and MFH has remained stable over time. Remarkable sex differences were found, with a higher prevalence among women than men with diabetes. Diabetes was associated with reporting in all the pain sites analyzed. Self-reported mental disease was associated with reporting CNP, CLBP, and MFH.

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Gradual Strength Training Improves Sleep Quality, Physical Function and Pain in Women with Fibromyalgia.

Fibromyalgia (FM) is characterized by chronic and generalized musculoskeletal pain. There is currently no cure for FM, but alternative treatments are available. Among them, gradual strength training programs (ST) which on daily activities are a valid option to improve some of the pronounced symptoms of FM that affect quality of life, such as fatigue, pain, sleep quality, and physical function. However, there is a need for more information on optimal training programs to improve anxiety and fatigue symptoms.

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A Review on Autophagy in Orofacial Neuropathic Pain.

Orofacial neuropathic pain indicates pain caused by a lesion or diseases of the somatosensory nervous system. It is challenging for the clinician to diagnose and manage orofacial neuropathic pain conditions due to the considerable variability between individual clinical presentations and a lack of understanding of the mechanisms underlying the etiology and pathogenesis. In the last few decades, researchers have developed diagnostic criteria, questionnaires, and clinical assessment methods for the diagnosis of orofacial neuropathic pain. Recently, researchers have observed the role of autophagy in neuronal dysfunction as well as in the modulation of neuropathic pain. On this basis, in the present review, we highlight the characteristics, classification, and clinical assessment of orofacial neuropathic pain. Additionally, we introduce autophagy and its potential role in the modulation of orofacial neuropathic pain, along with a brief overview of the pathogenesis, which in future may reveal new possible targets for treating this condition.

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Exploring the Tryptophan Metabolic Pathways in Migraine-Related Mechanisms.

Migraine is a complex neurovascular disorder, which causes intense socioeconomic problems worldwide. The pathophysiology of disease is enigmatic; accordingly, therapy is not sufficient. In recent years, migraine research focused on tryptophan, which is metabolized via two main pathways, the serotonin and kynurenine pathways, both of which produce neuroactive molecules that influence pain processing and stress response by disturbing neural and brain hypersensitivity and by interacting with molecules that control vascular and inflammatory actions. Serotonin has a role in trigeminal pain processing, and melatonin, which is another product of this pathway, also has a role in these processes. One of the end products of the kynurenine pathway is kynurenic acid (KYNA), which can decrease the overexpression of migraine-related neuropeptides in experimental conditions. However, the ability of KYNA to cross the blood-brain barrier is minimal, necessitating the development of synthetic analogs with potentially better pharmacokinetic properties to exploit its therapeutic potential. This review summarizes the main translational and clinical findings on tryptophan metabolism and certain neuropeptides, as well as therapeutic options that may be useful in the prevention and treatment of migraine.

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Opioid modulation of T-type Ca channel-dependent neuritogenesis/neurite outgrowth through the prostaglandin E/EP receptor/protein kinase A pathway in mouse dorsal root ganglion neurons.

Irregular regeneration or inappropriate remodeling of the axons of the primary afferent neurons after peripheral nerve trauma could be associated with the development of neuropathic pain. We analyzed the molecular mechanisms for the neuritogenesis and neurite outgrowth caused by prostaglandin E (PGE) in mouse dorsal root ganglion (DRG) neurons, and evaluated their opioid modulation. PGE in combination with IBMX, a phosphodiesterase inhibitor, caused neuritogenesis/neurite outgrowth in DRG cells, an effect abolished by a prostanoid EP, but not EP, receptor antagonist, and inhibitors of adenylyl cyclase or protein kinase A (PKA). Blockers of T-type Ca channels (T-channels), that are responsible for window currents involving the sustained low-level Ca entry at voltages near the resting membrane potentials and can be functionally upregulated by PKA, inhibited the neuritogenesis/neurite outgrowth caused by PGE/IBMX or dibutylyl cyclic AMP, a PKA activator, in DRG neurons, an inhibitory effect mimicked by ZnCl and ascorbic acid that block Ca3.2, but not Ca3.1 or Ca3.3, T-channels. Morphine and DAMGO, μ-opioid receptor (MOR) agonists, suppressed the neuritogenesis and/or neurite outgrowth induced by PGE/IBMX in DRG neurons and also DRG neuron-like ND7/23 cells, an effect reversed by naloxone or β-funaltrexamine, a selective MOR antagonist. Our data suggest that the EP receptor/PKA/Ca3.2 pathway is involved in the PGE-induced neuritogenesis/neurite outgrowth in DRG neurons, which can be suppressed by MOR stimulation. We propose that MOR agonists including morphine in the early phase after peripheral nerve trauma might delay the axonal regeneration of the primary afferent neurons but prevent the development of neuropathic pain.

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Using daily ratings to examine treatment dose and response in CBT for chronic pain: A secondary analysis of the Co-Operative Pain Education and Self-Management clinical trial.

Cognitive behavioral therapy for chronic pain (CBT-CP) has a strong evidence base, but little is known about when treatment benefits are achieved. The current study is a secondary analysis of individuals with chronic back pain recruited for a non-inferiority trial comparing interactive voice response (IVR) CBT-CP versus in-person CBT-CP. Using data from daily IVR surveys, a clinically meaningful change was defined as a 30% reduction in pain intensity (n = 108) or 45% increase in daily steps (n = 104) compared to baseline week. We identified individuals who achieved a meaningful change at any point during treatment, then we compared those who maintained a meaningful change in their final treatment week (i.e., responders) to those who did not or achieved a meaningful change but lapsed (i.e., non-responders). During treatment, 46% of participants achieved a clinically meaningful decrease in pain intensity, and 66% achieved a clinically significant increase in number of steps per day. A total of 54% of patients were classified as responders in terms of decreases in pain intensity, and 70% were responders in terms of increases in step count. Survival analyses found that 50% of responders first achieved a clinically meaningful change by week 4 for pain intensity and week 2 for daily steps. Dropout and demographic variables were unrelated to responder status and there was low agreement between the two measures of treatment response. Collectively, results suggest that most responders improve within 4 weeks. Evaluating treatment response is highly specific to the outcome measure with little correlation across outcomes.

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Preliminary evidence of safety and effectiveness of Loxoprofen Sodium Cataplasm combined with physiotherapy for myofascial pain syndrome treatment: A randomized controlled pilot clinical trial.

Myofascial pain syndrome (MPS) is one of the most common causes of chronic skeletal muscle pain, which is closely related to skeletal muscle myofascial trigger point (MTRP). Since there is no first-line treatment for MPS, we investigated Loxoprofen Sodium Cataplasm combined with physiotherapy as a non-invasive therapy in patients at different levels to a protocol with superior efficacy that is safe and easy to promote. Moreover, this treatment could represent an alternative therapeutic strategy for low-income patients to a safer, more convenient, and more economical treatment scheme.

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Effects of active musical engagement during physical exercise on anxiety, pain and motivation in patients with chronic pain.

The experience of anxiety is central to the development of chronic pain. Music listening has been previously shown to exert analgesic effects. Here we tested if an active engagement in music making is more beneficial than music listening in terms of anxiety and pain levels during physical activity that is often avoided in patients with chronic pain. We applied a music feedback paradigm that combines music making and sports exercise, and which has been previously shown to enhance mood. We explored this method as an intervention to potentially reduce anxiety in a group of patients with chronic pain (= 24, 20 female and 4 men; age range 34-64, 51.67,  = 6.84) and with various anxiety levels. All participants performed two conditions: one condition, , where exercise equipment was modified with music feedback so that it could be played like musical instruments by groups of three. Second, a where groups of three performed exercise on the same devices but where they listened to the same type of music passively. Participants' levels of anxiety, mood, pain and self-efficacy were assessed with standardized psychological questionnaires before the experiment and after each condition. Results demonstrate that exercise with musical feedback reduced anxiety values in patients with chronic pain significantly as compared to conventional workout with passive music listening. There were no significant overall changes in pain, but patients with greater anxiety levels compared to those with moderate anxiety levels were observed to potentially benefit more from the music feedback intervention in terms of alleviation of pain. Furthermore, it was observed that patients during more strongly perceived motivation through others. The observed diminishing effects of on anxiety have a high clinical relevance, and in a longer term the therapeutic application could help to break the Anxiety Loop of Pain, reducing chronic pain. The intervention method, however, also has immediate benefits to chronic pain rehabilitation, increasing the motivation to work out, and facilitating social bonding.

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Gut microbiota alterations may increase the risk of prescription opioid use, but not vice versa: A two-sample bi-directional Mendelian randomization study.

Gut microbiota alterations are strongly associated with prescription opioid use (POU) and multisite chronic pain (MCP). However, whether or not these associations are causal remains unknown. Therefore, we aim to explore the causal relationships between them comprehensively.

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Cerebral perfusion variance in new daily persistent headache and chronic migraine: an arterial spin-labeled MR imaging study.

New daily persistent headache (NDPH) and chronic migraine (CM) are two different types of headaches that might involve vascular dysregulation. There is still a lack of clarity about altered brain perfusion in NDPH and CM. This study aimed to investigate the cerebral perfusion variances of NDPH and CM using multi-delay pseudo-continuous arterial spin-labeled magnetic resonance imaging (pCASL-MRI).

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Long-Term Safety and Effectiveness of Erenumab in Patients with Migraine: A Systematic Review and Single-Arm Meta-analysis.

Several studies on use of erenumab for migraine treatment have been published over recent years. However, its long-term safety and effectiveness have not been consistently established in the literature yet. We aimed to perform a qualitative and quantitative analysis of the long-term safety and effectiveness of erenumab for the treatment of migraine headaches.

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Efficacy and Safety of Twice-Daily Tramadol Hydrochloride Bilayer Sustained-Release Tablets with an Immediate Release Component for Postherpetic Neuralgia: Results of a Phase III, Randomized, Double-Blind, Placebo-Controlled, Treatment-Withdrawal Study.

We investigated the efficacy and safety of twice-daily bilayer sustained-release tramadol hydrochloride tablets (35% immediate-release; 65% sustained-release) in patients with postherpetic neuralgia.

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Effects of ethanol on mechanical allodynia and dynamic weight bearing in male and female mice with spared nerve injury.

Men and women with chronic pain report increased alcohol use and are more likely to be diagnosed with alcohol use disorder. The relationship between alcohol use and pain is bidirectional with alcohol used as an analgesic, but chronic intake increasing pain. Sex differences in the relationship between chronic pain and alcohol are reported in the clinical and preclinical literature, but due to this bidirectional relationship, it is challenging to investigate the mechanisms that contribute to these differences. Thus, animal models of chronic pain are needed to characterize the efficacy of ethanol as an analgesic in males and females. The current experiments tested the hypothesis that ethanol would differentially reduce pain behaviors in male and female mice in chronic neuropathic pain.

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Anti-inflammatory biomolecular activity of chlorinated-phenyldiazenyl-naphthalene-2-sulfonic acid derivatives: perception from DFT, molecular docking, and molecular dynamic simulation.

In this study, two novel derivatives of naphthalene-2-sulfonic acid: 6-(((1S,5R)-3,5-dichloro-2,4,6-triazabicyclo [z3.1.0]hex-3-en-1-yl)amino)-5-((E)-phenyldiazenyl)naphthalene-2-sulfonic acid (DTPS1) and (E)-6-((4,6-dichloro-1,3,5-triazine2-yl)amino)-4-hydroxy-3-(phenyldiazenyl)naphthalene-2-sulfonic acid (DTPS2) have been synthesized and characterized using FT-IR, UV-vis, and NMR spectroscopic techniques. Applying density functional theory (DFT) at the B3LYP, APFD, PBEPBE, HCTH, TPSSTPSS, and ωB97XD/aug-cc-pVDZ level of theories for the electronic structural properties. In-vitro analysis, molecular docking, molecular dynamic (MD) simulation of the compounds was conducted to investigate the anti-inflammatory potential using COXs enzymes. Docking indicates binding affinity of -9.57, -9.60, -6.77 and -7.37 kcal/mol for DTPS1, DTPS2, Ibuprofen and Diclofenac which agrees with assay. Results of MD simulation, indicates sulphonic group in DTPS1 has > 30% interaction with the hydroxyl and oxygen atoms in amino acid residues, but > 35% interaction with the DTPS2. It can be said that the DTPS1 and DTPS2 can induce inhibitory effect on COXs to halt biosynthesis of prostaglandins (PGs), a chief mediator of inflammation and pain in mammals.Communicated by Ramaswamy H. Sarma.

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Project EPIC (Early Palliative Care In COPD): A Multiphase Evaluation of the EPIC Telehealth Intervention.

Early, concurrent palliative care interventions in chronic obstructive pulmonary disease (COPD) are limited. Project EPIC (Early Palliative Care In COPD) is a multiphase mixed methods study working to fill this gap.

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Editorial: Pain in multiple sclerosis and experimental autoimmune encephalomyelitis.

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Preferences of patients with chronic low back pain about nonsurgical treatments: Results of a discrete choice experiment.

This study aimed to assess patients' preferences of nonsurgical treatments for chronic low back pain (CLBP).

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Effectiveness of losartan on infrapatellar fat pad/synovial fibrosis and pain behavior in the monoiodoacetate-induced rat model of osteoarthritis pain.

Infrapatellar fat pad (IFP)/ synovial fibrosis is closely associated with the clinical symptoms of joint pain and stiffness, which contribute to locomotor restriction in osteoarthritis (OA) patients. Hence, this study was designed to gain insight on whether losartan, a selective angiotensin II type 1 receptor (AT1R) antagonist, has therapeutic benefit to reverse IFP/synovial fibrosis and secondarily to attenuate pain behavior. In male Wistar rats with monoiodoacetic acid (MIA)-induced IFP/synovial fibrosis, a possible role for increased AT1R expression in the pathogenesis of IFP/synovial fibrosis was assessed over an 8-week period. Pain behavior comprised static weight bearing and von Frey paw withdrawal thresholds (PWTs), which were assessed once or twice weekly, respectively. Groups of MIA-rats received oral losartan (30-mg/kg; n = 8 or 100-mg/kg; n = 9) or vehicle (n = 9) for 28-days according to a prevention protocol. Animals were euthanized on day 28 and various tissues (IFP/synovium, cartilage and lumbar dorsal root ganglia (DRGs)) were collected for histological, immunohistochemical and western blot analyses. Administration of once-daily losartan for 28-days dose-dependently attenuated the development of static weight bearing. This was accompanied by reduced IFP/synovial fibrosis and suppression of TGF-β1 expression. Chronic treatment of MIA-rats with losartan had an anti-fibrotic effect and it attenuated pain behavior in this animal model.

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Critical care nurses’ perceived barriers and enablers of pain assessment and management.

To examine critical care nurses' perceived barriers and enablers of pain assessment and management. This descriptive correlational study recruited a convenience sample of 200 Jordanian nurses. Pain Assessment and Management for the Critically Ill questionnaire was used to measure the study variables. The most common barriers to pain assessment and management were patient inability to communicate (57.5%), patient instability (56.5%), and the lack of protocols/guidelines for pain assessment (55.0%). Whereas the most common enablers for effective pain management practices were the ongoing education on pain for nurses (60.5%) and physicians who prescribe adequate doses of analgesia (60.0%). Addressing nurses' perceived barriers and the enablers of pain assessment and management is crucial for optimal pain practice.

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The potential roles of JAK/STAT signaling in the progression of osteoarthritis.

Osteoarthritis (OA) is an age-related chronic progressive degenerative disease that induces persistent pain and disabilities. The development of OA is a complex process, and the risk factors are various, including aging, genetics, trauma and altered biomechanics. Inflammation and immunity play an important role in the pathogenesis of OA. JAK/STAT pathway is one of the most prominent intracellular signaling pathways, regulating cell proliferation, differentiation, and apoptosis. Inflammatory factors can act as the initiators of JAK/STAT pathway, which is implicated in the pathophysiological activity of chondrocyte. In this article, we provide a review on the importance of JAK/STAT pathway in the pathological development of OA. Potentially, JAK/STAT pathway becomes a therapeutic target for managing OA.

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Identifying and Managing Suicidality in Children and Adolescents with Chronic Pain: Evidence-Based Treatment Strategies.

Children and adolescents with chronic pain are at an increased risk of suicidality. This narrative review article aims to inform clinical practice in the assessment and management of suicidality in youth with chronic pain. The article begins with a survey of the background and prevalence of youth with chronic pain. A review of the current evidence behind the increased risk of suicidality in youth with chronic pain follows. Contextualization of this data with general tenets of child and adolescent suicide risk and risk assessment is provided. Suicidology theory including the interpersonal theory of suicide is overviewed to help clinicians to conceptualize the reviewed data. Guiding parameters for the suicide risk assessment and management planning is presented. Concluding recommendations are made to guide clinical practice in the assessment and management of suicidality in youth with chronic pain.

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Development of a personalized shared decision-making tool for knee osteoarthritis and user-testing with African American and Latina women.

Patients with chronic knee pain are often unaware of treatment options and likely outcomes-information that is critical to decision-making. A consistent framework for communicating patient-personalized information enables clinicians to provide consistent, targeted, and relevant information. Our objective was to user-test a shared decision-making (SDM) tool for chronic knee pain.

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“My Fibro Family!” A qualitative analysis of facebook fibromyalgia support groups’ discussion content.

Fibromyalgia (FM) is a diagnostically controversial syndrome characterized by chronic widespread pain, fatigue, sleep difficulties, cognitive dysfunction, and mental health symptoms. Though online peer support groups (OPSGs) may help persons with FM access support and information, there are concerns that such groups can be harmful.

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Management of Opioid-induced Constipation in Older Adults.

Opioid-induced constipation (OIC) is a common condition in older adults who may not be responsive to traditional laxative therapy. OIC is defined as new or worsening constipation symptoms that occur with initiation of or altering the dose of opioid analgesia. For adult patients with OIC and noncancer pain, we recommend considering nonpharmacologic interventions (eg, dietary measures, increased physical activity, and biofeedback training) and over-the-counter laxatives, followed by prescription opioid receptor antagonists (methylnaltrexone, naloxegol, and naldemedine) if traditional over-the-counter laxatives fail. Other options may include lubiprostone, linaclotide, plecanatide, and prucalopride; however, these are not indicated for OIC specifically or studied in older adults. Because of the complex nature of absorption, distribution, metabolism, and excretion in the aging population, all agents used to treat OIC must be evaluated individually and reevaluated as patients continue to age. This review will serve as a guide to managing OIC in older adults.

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Pain trajectories of nursing home residents.

Understanding changes in nursing home (NH) resident pain over time would provide a more informed perspective, allowing opportunities to alter the course of illness, plan care, and set priorities. Therefore, the purpose of this analysis was to identify and characterize clinically meaningful, dynamic pain trajectories in NH residents.

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Psoriatic arthritis: review of potential biomarkers predicting response to TNF inhibitors.

Psoriatic arthritis (PsA) is a chronic and painful inflammatory immune-mediated disease. It affects up to 40% of people with psoriasis and it is associated with several comorbidities such as obesity, diabetes, metabolic syndrome, and hypertension. PsA is difficult to diagnose because of its diverse symptoms, namely axial and peripheral arthritis, enthesitis, dactylitis, skin changes, and nail dystrophy. Different drugs exist to treat the inflammation and pain. When patients do not respond to conventional drugs, they are treated with biologic drugs. Tumour necrosis factor inhibitors (TNFi's) are commonly given as the first biologic drug; beside being expensive, they also lack efficacy in 50% of patients. A biomarker predicting individual patient's response to TNFi would help treating them earlier with an appropriate biologic drug. This study aimed to review the literature to identify potential biomarkers that should be investigated for their predictive ability. Several such biomarkers were identified, namely transmembrane TNFα (tmTNF), human serum albumin (HSA) and its half-life receptor, the neonatal Fc receptor (FcRn) which is also involved in IgG lifespan; calprotectin, high mobility group protein B1 (HMGB1) and advanced glycation end products (AGEs) whose overexpression lead to excessive production of pro-inflammatory cytokines; lymphotoxin α (LTα) which induces inflammation by binding to TNF receptor (TNFR); and T helper 17 (Th17) cells which induce inflammation by IL-17A secretion.

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Endometriosis: A multimodal imaging review.

Endometriosis is a chronic inflammatory disorder characterized endometrial-like tissue present outside of the uterus, affecting approximately 10% of reproductive age women. It is associated with abdomino-pelvic pain, infertility and other non – gynecologic symptoms, making it a challenging diagnosis. Several guidelines have been developed by different international societies to diagnose and classify endometriosis, yet areas of controversy and uncertainty remains. Transvaginal ultrasound (TV-US) is the first-line imaging modality used to identify endometriosis due to its accessibility and cost-efficacy. Enhanced sonographic techniques are emerging as a dedicated technique to evaluate deep infiltrating endometriosis (DIE), depending on the expertise of the sonographer as well as the location of the lesions. MRI is an ideal complementary modality to ultrasonography for pre-operative planning as it allows for a larger field-of-view when required and it has high levels of reproducibility and tolerability. Typically, endometriotic lesions appear hypoechoic on ultrasonography. On MRI, classical features include DIE T2 hypointensity, endometrioma T2 hypointensity and T1 hyperintensity, while superficial peritoneal endometriosis (SPE) is described as a small focus of T1 hyperintensity. Imaging has become a critical tool in the diagnosis, surveillance and surgical planning of endometriosis. This literature review is based mostly on studies from the last two decades and aims to provide a detailed overview of the imaging features of endometriosis as well as the advances and usefulness of different imaging modalities for this condition.

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Broaden Horizons: The Advancement of Interstitial Cystitis/Bladder Pain Syndrome.

Interstitial cystitis/bladder pain syndrome (IC/BPS) is a debilitating disease that induces mental stress, lower urinary symptoms, and pelvic pain, therefore resulting in a decline in quality of life. The present diagnoses and treatments still lead to unsatisfactory outcomes, and novel diagnostic and therapeutic modalities are needed. Although our understanding of the etiology and pathophysiology of IC/BPS is growing, the altered permeability of the impaired urothelium, the sensitized nerves on the bladder wall, and the chronic or intermittent sensory pain with inaccurate location, as well as pathologic angiogenesis, fibrosis, and Hunner lesions, all act as barriers to better diagnoses and treatments. This study aimed to summarize the comprehensive information on IC/BPS research, thereby promoting the progress of IC/BPS in the aspects of diagnosis, treatment, and prognosis. According to diverse international guidelines, the etiology of IC/BPS is associated with multiple factors, while the presence of Hunner lesions could largely distinguish the pathology, diagnosis, and treatment of non-Hunner lesions in IC/BPS patients. On the basis of the diagnosis of exclusion, the diverse present diagnostic and therapeutic procedures are undergoing a transition from a single approach to multimodal strategies targeting different potential phenotypes recommended by different guidelines. Investigations into the mechanisms involved in urinary symptoms, pain sensation, and bladder fibrosis indicate the pathophysiology of IC/BPS for further potential strategies, both in diagnosis and treatment. An overview of IC/BPS in terms of epidemiology, etiology, pathology, diagnosis, treatment, and fundamental research is provided with the latest evidence. On the basis of shared decision-making, a multimodal strategy of diagnosis and treatment targeting potential phenotypes for individual patients with IC/BPS would be of great benefit for the entire process of management. The complexity and emerging evidence on IC/BPS elicit more relevant studies and research and could optimize the management of IC/BPS patients.

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Health-Related Quality of Life in Migraine: EQ-5D-5L-Based Study in Routine Clinical Practice.

Migraine leads to moderate to severe disabilities and disrupts family life, interpersonal relationships, and professional life, and is the second leading cause of disability worldwide. Many people with migraine suffer prolonged headaches and frequent migraine attacks, transition to having chronic migraine, and have the highest number of disability-adjusted life-years. The aim of this study is to measure the quality of life in migraineurs based on the EQ-5D-5L questionnaire.

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The Therapeutic Effect of Phosphopeptide P140 Attenuates Inflammation Induced by Uric Acid Crystals in Gout Arthritis Mouse Model.

Gout is a painful form of inflammatory arthritis characterized by the deposition of monosodium urate (MSU) crystals in the joints. The aim of this study was to investigate the effect of peptide P140 on the inflammatory responses in crystal-induced mouse models of gout and cell models including MSU-treated human cells. Injection of MSU crystals into the knee joint of mice induced neutrophil influx and inflammatory hypernociception. Injection of MSU crystals subcutaneously into the hind paw induced edema and increased pro-inflammatory cytokines levels. Treatment with P140 effectively reduced hypernociception, the neutrophil influx, and pro-inflammatory cytokine levels in these experimental models. Furthermore, P140 modulated neutrophils chemotaxis in vitro and increased apoptosis pathways through augmented caspase 3 activity and reduced NFκB phosphorylation. Moreover, P140 increased the production of the pro-resolving mediator annexin A1 and decreased the expression of the autophagy-related ATG5-ATG12 complex and HSPA8 chaperone protein. Overall, these findings suggest that P140 exerts a significant beneficial effect in a neutrophilic inflammation observed in the model of gout that can be of special interest in the design of new therapeutic strategies.

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Patient-centered consultations for persons with musculoskeletal conditions.

Consultations between practitioners and patients are more than a hypothesis-chasing exploration, especially when uncertainty about etiology and prognosis are high. In this article we describe a single individual's account of their lived experience of pain and long journey of consultations. This personal account includes challenges as well as opportunities, and ultimately led to self-awareness, clarity, and living well with pain. We follow each section of this narrative with a short description of the emerging scientific evidence informing on specific aspects of the consultation. Using this novel structure, we portray a framework for understanding consultations for persistent musculoskeletal pain from a position of patient-centered research to inform practice.

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Quantifying implementation strategy and dissemination channel preferences and experiences for pain management in primary care: a novel implementer-reported outcome.

Precision implementation science requires methods to evaluate and select implementation strategies. This study developed and evaluated a novel measure of concordance between current and preferred dissemination channels (DC) and implementation strategies (IS) to guide efforts to improve the adoption of evidence-based management strategies for chronic pain.

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Keloid disease: Review with clinical atlas. Part I: Definitions, history, epidemiology, clinics and diagnosis.

Keloids are chronic progressive dermal pseudo-tumors that can grow considerably in volume and surface area but do not invade other tissues. They are usually triggered by dermal injury or inflammation, but they are not scars in the normal sense of the word, since they enlarge and progress over decades. The phenomenon usually referred to as "hypertrophic scars" represents a kind of keloidal process that does not extend beyond the initial site of injury and spontaneously regresses in 12-24 months. The multiplication of keloids and hypertrophic scars in a single patient is known as keloid disease. Keloid disease is due to a familial predisposition (autosomal dominant) that preferentially affects people of non-European ancestry, especially those of sub-Saharan African descent. Keloid disease has a deep impact on quality of life, not only because of disfiguring lesions, but also because of the frequency of associated intense neurogenic pruritus and pain, as well as recurrent bouts of suppuration. Diagnosis relies primarily on a good knowledge of the clinical characteristics of keloids, thus warranting the inclusion of a clinical atlas in the first part of the review. The second part will deal with the pathology, pathophysiology and treatment of keloid disease.

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Knowledge Mapping of International Research on Acupuncture for Chronic Pain: A Bibliometric Analysis.

With the wide acceptance of acupuncture, many papers and guidelines recommend that acupuncture is effective for chronic pain (CP). In this study, we applied bibliometric methods to analyze the current research situation of acupuncture intervention in CP, to gain insight into the current situation and future development trend of this field.

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A Comparative Review of the Outcome following MVD and PBC in Patients with Trigeminal Neuralgia.

Objective This study is aimed to systematically review the treatment outcomes between percutaneous balloon compression (PBC) and microvascular decompression (MVD) in patients with trigeminal neuralgia. Methods A systematic review in accordance with the PRISMA guideline was performed using PubMed, Embase and Cochrane CENTRAL databases. Only those articles with more than 5 years' follow-up length were included in this investigation. In order to uniformly assess the postoperative outcome, we defined pain relief for those totally pain free, while the postoperative hospitalization and last follow-up period as early and long-term, respectively. The facial numbness was quantified with BNI score. Results After database searching and screening, 7797 cases were enrolled finally according the criteria. The early pain relief rates were 94.1% (1551/1649) and 89.9% (4962/5482) following PBC and MVD (OR=0.603, p<0.05), while the long-term 58.1% (921/1566) and 74.9% (4549/6074) (OR=2.089, p<0.05), respectively. Although a significant higher facial numbness occurred in PBC group in the early stage, it was mostly diminished 5 years later compared with MVD group. At long-term follow-up, hypoacousia and facial palsy occurred more often in MVD group (p<0.05). Conclusions Both MVD and PBC provide a satisfactory outcome for the patients in long-term. As a simple, safe and reliable technique, PBC should not be shrugged off by neurosurgeons.

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What Are Orthopaedic Patients’ and Clinical Team Members’ Perspectives Regarding Whether and How to Address Mental Health in the Orthopaedic Care Setting? A Qualitative Investigation of Patients With Neck or Back Pain.

Across virtually all orthopaedic subspecialties, symptoms of depression, anxiety, and unhelpful thinking are associated with worse patient-reported satisfaction with orthopaedic treatment and increased postoperative complications. In the orthopaedic community, there is growing interest in patients' mental health in the orthopaedic care setting, but addressing mental health is still not a focus of orthopaedic clinical training. There is a persistent awareness gap about how to address mental health in orthopaedic care in a manner that is simultaneously feasible in a busy orthopaedic practice and acceptable to patients who are presenting for treatment of a musculoskeletal condition.

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Changes and associations between gait biomechanics and knee inflammation after aspiration and corticosteroid injection for knee osteoarthritis.

Although knee inflammation is thought to adversely affect joint function in patients with knee osteoarthritis (OA), the effects of reducing knee inflammation on gait biomechanics and strength are unknown. Our objectives were to compare ultrasound (US) measures of knee inflammation, gait biomechanics, knee extension and flexion strength, and pain before and after knee aspiration and corticosteroid injection; and explore associations among changes.

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