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Papers: 6 Aug 2022 - 12 Aug 2022

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Distinct neural networks derived from galanin-containing nociceptors and neurotensin-expressing pruriceptors.

Pain and itch are distinct sensations arousing evasion and compulsive desire for scratching, respectively. It's unclear whether they could invoke different neural networks in the brain. Here, we use the type 1 herpes simplex virus H129 strain to trace the neural networks derived from two types of dorsal root ganglia (DRG) neurons: one kind of polymodal nociceptors containing galanin () and one type of pruriceptors expressing neurotensin (). The DRG microinjection and immunosuppression were performed in transgenic mice to achieve a successful tracing from specific types of DRG neurons to the primary sensory cortex. About one-third of nuclei in the brain were labeled. More than half of them were differentially labeled in two networks. For the ascending pathways, the spinothalamic tract was absent in the network derived from -expressing pruriceptors, and the two networks shared the spinobulbar projections but occupied different subnuclei. As to the motor systems, more neurons in the primary motor cortex and red nucleus of the somatic motor system participated in the -containing nociceptor-derived network, while more neurons in the nucleus of the solitary tract (NST) and the dorsal motor nucleus of vagus nerve (DMX) of the emotional motor system was found in the -expressing pruriceptor-derived network. Functional validation of differentially labeled nuclei by c-Fos test and chemogenetic inhibition suggested the red nucleus in facilitating the response to noxious heat and the NST/DMX in regulating the histamine-induced scratching. Thus, we reveal the organization of neural networks in a DRG neuron type-dependent manner for processing pain and itch.

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Gut Microbiota Alter Visceral Pain Sensation and Inflammation via Modulation of Synthesis of Resolvin D1 in Colonic Tuft Cells.

Visceral hypersensitivity and low grade mucosal inflammation are frequently observed in a subpopulation of irritable bowel syndrome (IBS) patients. The responsible mechanism is unclear. Resolvins are a novel class of anti-inflammatory lipid mediators that regulate resolution of inflammation and pain. We hypothesize that resolvin D1 (RvD1) synthesis is reduced in IBS-D colonic mucosa and contribute to the development of visceral hypersensitivity.

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Effect of Adjunctive Acupuncture on Pain Relief Among Emergency Department Patients With Acute Renal Colic Due to Urolithiasis: A Randomized Clinical Trial.

Renal colic is described as one of the worst types of pain, and effective analgesia in the shortest possible time is of paramount importance.

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Epigenetic Aging Mediates the Association between Pain Impact and Brain Aging in Middle to Older Age Individuals with Knee Pain.

Chronic musculoskeletal pain is a health burden that may accelerate the aging process. Accelerated brain aging and epigenetic aging have separately been observed in those with chronic pain. However, it is unknown whether these biological markers of aging are associated with each other in those with chronic pain. We aimed to explore the association of epigenetic aging and brain aging in middle-to-older age individuals with varying degrees of knee pain. Participants (57.91 ± 8.04 years) with low impact knee pain (n=95), high impact knee pain (n=53) and pain-free controls (n=26) completed self-reported pain, a blood draw and an MRI scan. We used an epigenetic clock previously associated with knee pain (DNAmGrimAge), the subsequent difference of predicted epigenetic and brain age from chronological age (DNAmGrimAge-Difference and Brain-PAD, respectively). There was a significant main effect for pain impact group ( (2,167) = 3.847, p = 0.023, = 0.038, ANCOVA) on Brain-PAD and DNAmGrimAge-difference ( (2,167) = 6.800, p = 0.001, = 0.075, ANCOVA) after controlling for covariates. DNAmGrimAge-Difference and Brain-PAD were modestly correlated (r=0.198; p=0.010). Exploratory analysis revealed that DNAmGrimAge-difference mediated GCPS pain impact, GCPS pain severity and pain related disability scores on Brain-PAD. Based upon the current study findings, we suggest that pain could be a driver for accelerated brain aging via epigenome interactions.

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No long-term effects after a three-week open-label placebo treatment for chronic low back pain: a three-year follow-up of a randomized controlled trial.

Chronic low back pain is prevalent, highly disabling and a relevant socioeconomic health concern. Although allocated to placebo groups, patients in randomized controlled trials show significant pain relief, pointing to the relevance of placebo effects. Overcoming ethical and legal concerns related to deceptive placebos, recent studies have demonstrated the efficacy of short-term treatments for chronic low back pain with open-label (i.e., non-deceptive) placebos. However, data on long-term efficacy of open-label placebos are sparse. Here, we report a three-year follow-up of our previously published randomized controlled trial demonstrating pain reduction, improvement in disability and depressive symptoms after a three-week treatment with open-label placebos. Including records from N=89 previously enrolled patients, we investigated changes between the groups with and without previous open-label placebo treatment in pain intensity (primary outcome), disability and mood (secondary outcomes), biopsychosocial factors and lifestyle (exploratory outcomes) from parent baseline to follow-up. Over the three-year period, there were no differences in any outcome between groups with and without open-label placebo treatment. Therefore, our follow-up data do not support the previously suggested assumption that a three-week open-label placebo treatment has long-term effects. This study was pre-registered on April 14, 2020, in the German Clinical Trials Register (registration number DRKS00021405).

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Sex effects in the interaction of acute stress and pain perception.

A reciprocity between the stress and the pain system is recognized; however, the manner by which sex affects this reciprocity is unclear. Understanding the interactions of stress, pain, and sex may shed light on the apparent women's vulnerability to chronic pain, which often co-exists with increased distress, and to affective disorders, which often co-exist with chronic pain. The study's aim was to examine the effect of acute, validated, psychosocial stress on pain perception and modulation of women and men in a controlled manner. Participants were 82 women and 66 men. Heat-pain threshold, heat-pain tolerance and pain modulation by temporal summation of pain (TSP), and pain adaptation, were measured before and after exposure to the Montreal Imaging Stress Task (MIST) or to a sham task. The stress response was verified by perceived ratings of stress and anxiety, autonomic variables, and salivary cortisol. A significant stress response was obtained by the MIST among both sexes; however, women displayed a greater increase in perceived distress, and men displayed a greater increase in cortisol. Among women, TSP decreased and pain adaptation increased following the MIST, responses that were predicted by perceived distress levels. Among men, TSP increased following the MIST but was not predicted by the stress variables. In conclusion, acute stress manipulation seems to differentially affect both stress and pain responses of women and men: Women exhibited stress-induced antinociception, and men exhibited stress-induced pronociception. Higher perceived stress levels among women may trigger a temporary increase in pain inhibition mechanisms to serve evolutionary purposes.

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Attentional bias malleability as a predictor of daily pain interference.

Despite a preponderance of pain-related attentional bias research, little is known about how these biases arise and change over time. We tested whether the degree of attentional bias malleability, that is, ability to acquire and relinquish patterns of selective attention towards pain information, predicts daily pain interference. Individuals with chronic pain (N = 66) completed a novel attentional bias malleability procedure based on a modified dot-probe paradigm. Participants received a contingency that encouraged an attentional preference toward and away from pain words across two counterbalanced blocks, and attentional bias was assessed before and after each contingency block. Participants then completed a daily diary for 7 days, including PROMIS-29 pain severity and interference. Multilevel modelling was conducted to predict daily pain interference from attentional bias malleability constructs, controlling for pain severity and demographic factors. Greater attentional bias (F1,391 = 3.97, p = .047), greater readiness to acquire an attentional bias (F1,389) = 4.92, p = .027), and less readiness to lose an acquired attentional bias toward pain (F1,354 = 5.18, p = .024) all predicted less pain interference. There was also an interaction between pain severity and overall attentional bias malleability (F1,62 = 5.48, p = .023), such that as pain severity increased, those who showed greater attentional bias malleability showed less corresponding increase in their pain interference, than those who showed less attentional bias malleability. This study adds new thinking to the dynamic nature of attentional bias, and how such biases might arise and influence pain outcomes.

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Trends in pelvic pain symptoms over two years of follow-up among adolescents and young adults with and without endometriosis.

We described trends in pelvic pain characteristics over two years of follow-up among adolescents and adults with and without endometriosis participating in the longitudinal observational cohort of the Women's Health Study: From Adolescence to Adulthood (A2A), utilizing data reported at baseline and at years one and two of follow-up. Participants completed a questionnaire at baseline (between November 2012-May 2019) and annually thereafter that included validated measures of severity, frequency, and life interference of dysmenorrhea, acyclic pelvic pain, and dyspareunia. Our study population included 620 participants with surgically-confirmed endometriosis (rASRM stage I/II=95%) and 671 community and hospital-based controls; median age=19 and 24 years, respectively. The proportion reporting hormone use varied across the three years ranging from 88%-92% for cases and 56%-58% for controls. At baseline, endometriosis cases were more likely to report severe, frequent, and life interfering dysmenorrhea, acyclic pelvic pain, and dyspareunia compared to controls. Among cases, frequency and severity of dysmenorrhea and dyspareunia were relatively static across two years. However, acyclic pelvic pain improved. Severe acyclic pain decreased from 69% at baseline to 46% at Year 2. Daily pain decreased from 28% to 14%, and life interference from 68% to 38%. Trends among controls remained fairly stable across 2 years. Among endometriosis cases who completed the questionnaire at all three time points, 18% reported persistent, severe acyclic pelvic pain at all three time-points. Over time, different trends were observed by pelvic pain type among endometriosis cases and controls, supporting the importance of assessing multi-dimensional features of pelvic pain.

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Variations in comorbidity burden in people with type 2 diabetes over disease duration: A population-based analysis of real world evidence.

The prevalence of type 2 diabetes (T2DM) is increasing, but increasing longevity among persons with diagnosed diabetes may be is associated with more extensive and diverse types of morbidity. The extent and breadth of morbidity and how this varies across sub-groups is unclear and could have important clinical and public health implications. We aimed to estimate comorbidity profiles in people with T2DM and variations across sub-groups and over time.

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Is mindfulness associated with lower pain reactivity and connectivity of the default mode network? A replication and extension study in healthy and episodic migraine participants.

Formal training in mindfulness-based practices promotes reduced experimental and clinical pain, which may be driven by reduced emotional pain reactivity and undergirded by alterations in the default mode network, implicated in mind-wandering and self-referential processing. Recent results published in this journal suggest that mindfulness, defined here as the day-to-day tendency to maintain a non-reactive mental state in the absence of training, associates with lower pain reactivity, greater heat-pain thresholds, and resting-state default mode network functional connectivity in healthy adults in a similar manner to trained mindfulness. The extent to which these findings extend to chronic pain samples and replicate in healthy samples is unknown. Using data from healthy adults (n = 36) and episodic migraine patients (n = 98) and replicating previously published methods, we observed no significant association between mindfulness and heat-pain threshold, pain intensity or unpleasantness, or pain catastrophizing in healthy controls, or between mindfulness and headache frequency, severity, impactor pain catastrophizing in patients. There was no association between default mode network connectivity and mindfulness in either sample when probed via seed-based functional connectivity analyses. In post-hoc whole brain exploratory analyses, a meta-analytically derived default mode network node (i.e., posterior cingulate cortex) showed connectivity with regions unassociated with pain processing as a function of mindfulness, such that healthy adults higher in mindfulness showed greater functional connectivity between the posterior cingulate cortex-and cerebellum. Collectively, these findings suggest that the relationship between mindfulness and default mode network functional connectivity may be nuanced or non-robust, and encourage further investigation of how mindfulness relates to pain. Perspective: This study found few significant associations between dispositional mindfulness and pain, pain reactivity and default mode connectivity in healthy adults and migraine patients. The relationship between mindfulness and default mode network connectivity may be nuanced or non-robust.

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Key Learning Statements for persistent pain education: an iterative analysis of consumer, clinician and researcher perspectives and development of public messaging.

Over the last decade, the content, delivery and media of pain education have been adjusted in line with scientific discovery in pain and educational sciences, and in line with consumer perspectives. This paper describes a decade-long process of exploring consumer perspectives on pain science education concepts to inform clinician-derived educational updates (undertaken by the authors). Data were collected as part of a quality audit via a series of online surveys in which consent (non-specific) was obtained from consumers for their data to be used in published research. Consumers who presented for care for a persistent pain condition and were treated with a pain science education informed approach were invited to provide anonymous feedback about their current health status and pain journey experience 6, 12 or 18 months after initial assessment. Two-hundred eighteen consumers reported improvement in health status at follow-up. Results of the surveys from three cohorts of consumers that reported improvement were used to generate iterative versions of 'Key Learning Statements'. Early iteration of these Key Learning Statements was used to inform the development of Target Concepts and associated community-targeted pain education resources for use in public health and health professional workforce capacity building initiatives. Perspective This paper reflects an explicit interest in the insights of people who have been challenged by persistent pain and then recovered, to improve pain care. Identifying pain science concepts that consumers valued learning provided valuable information to inform resources for clinical interactions and community-targeted pain education campaigns.

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Persistence of somatic symptoms after COVID-19 in the Netherlands: an observational cohort study.

Patients often report various symptoms after recovery from acute COVID-19. Previous studies on post-COVID-19 condition have not corrected for the prevalence and severity of these common symptoms before COVID-19 and in populations without SARS-CoV-2 infection. We aimed to analyse the nature, prevalence, and severity of long-term symptoms related to COVID-19, while correcting for symptoms present before SARS-CoV-2 infection and controlling for the symptom dynamics in the population without infection.

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MAO-B inhibitor, KDS2010, alleviates spinal nerve ligation-induced neuropathic pain in rats through competitively blocking the BDNF/TrkB/NR2B signaling.

MAO-B inhibitors have been implicated to reverse neuropathic pain behaviors. Our previous study has demonstrated that KDS2010 (KDS), a newly developed reversible MAO-B inhibitor, could attenuate Paclitaxel (PTX)-induced tactile hypersensitivity in mice through suppressing reactive oxidant species (ROS)-decreased inhibitory GABA synaptic transmission in the spinal cord. In this study, we evaluated the analgesic effect of KDS under a new approach, in which KDS acts on dorsal horn sensory neurons to reduce excitatory transmission. Oral administration of KDS effectively enhanced mechanical thresholds in the spinal nerve ligation (SNL) induced neuropathic pain in rats. Moreover, we discovered that although treatment with KDS increased brain-derived neurotrophic factor (BDNF) levels, KDS inhibited Tropomyosin receptor kinase B (TrkB) receptor activation, suppressing increased p-NR2B-induced hyperexcitability in spinal dorsal horn sensory neurons after nerve injury. In addition, KDS showed its anti-inflammatory effects by reducing microgliosis and astrogliosis and the activation of MAPK and NF-ᴋB inflammatory pathways in these glial cells. The levels of ROS production in the spinal cords after the SNL procedure were also decreased with KDS treatment. Taken together, our results suggest that KDS may represent a promising therapeutic option for treating neuropathic pain. Perspective: Our study provides evidence suggesting the mechanisms by which KDS, a novel MAO-B inhibitor, can be effective in pain relief. KDS, by targeting multiple mechanisms involved in BDNF/TrkB/NR2B-related excitatory transmission and neuroinflammation, may represent the next future of pain medicine.

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Patient-Centered Pain Care Using Artificial Intelligence and Mobile Health Tools: A Randomized Comparative Effectiveness Trial.

Cognitive behavioral therapy for chronic pain (CBT-CP) is a safe and effective alternative to opioid analgesics. Because CBT-CP requires multiple sessions and therapists are scarce, many patients have limited access or fail to complete treatment.

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Exploring the trajectory curve of long-term musculoskeletal post-COVID pain symptoms in hospitalized COVID-19 survivors: a multicenter study.

This multicenter cohort study investigated the prevalence of musculoskeletal post-COVID pain during the first year after the infection with mosaic plots and an exponential bar plot model and its associated risk factors. Patients hospitalized because of COVID-19 in 5 hospitals of Madrid (Spain) were scheduled for a telephone interview at 2 follow-up periods after hospitalization for collecting data about musculoskeletal post-COVID pain. Hospitalization and clinical data were collected from hospital medical records. From 2000 patients initially recruited, 1593 (44.6% women, age: 61 +/- 15 years) were assessed at T0 (hospital admission), T1 (mean: 8.0 +/- 1.5 months after discharge), and T2 (mean: 13.2 +/- 1.5 months after discharge). The prevalence of musculoskeletal pain (myalgia) was 30.3% (n = 483) at T0, increased to 43.4% (n = 692) at T1, and decreased to 37.8% (n = 603) at T2. The trajectory curve revealed a decreasing prevalence trend of musculoskeletal post-COVID pain the following years after hospitalization. According to the presence of pre-existing pain symptoms, the prevalence of new-onset post-COVID pain was 75.9%. Female sex (odds ratio [OR] 1.593, 95% confidence interval [CI] 1.148-2.211), history of musculoskeletal pain (OR 1.591, 95% CI 1.211-2.07), the presence of myalgia (OR 1.371, 95% CI 1.032-1.821) or headache (OR 2.278, 95% CI 1.622-3.199) at hospitalization, the days of hospitalization (OR 1.013, 95% CI 1.000-1.025), and the presence of post-COVID pain at T1 (OR 11.02, 95% CI 8.493-14.305) were factors associated with musculoskeletal post-COVID pain 1 year after hospitalization. In conclusion, musculoskeletal post-COVID pain remains highly prevalent 1 year after hospitalization. Female sex, previous history of pain symptoms, pain symptoms at onset, and days at hospital were factors associated with musculoskeletal post-COVID pain 1 year after hospitalization.

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N-Ethylnorketamine has anesthetic and analgesic effects with abuse liability.

Arylcyclohexylamines is an ever-growing class of new psychoactive substances, including an increasing number of ketamine analogues. N-Ethylnorketamine (NENK) is a new synthetic ketamine analogue that has emerged as an abused drug, but little is known about the pharmacological profile of NENK. In this study, we investigated the anesthetic and analgesic activity, abuse liability of NENK compared with ketamine. The ED values of anesthetic activity for NENK and ketamine were 96.9, 69.4mg/kg, respectively. The ED values of analgesic activity for NENK and ketamine were 45.9 and 23.6mg/kg, respectively. NENK induced significant conditioned place preference at a minimum dose of 10.0mg/kg in mice, an effect comparable to that of ketamine (3.0mg/kg). Acute injections of NENK or ketamine at 30.0mg/kg enhanced locomotor activity, and repeated treatments with this dose induced locomotor sensitization after withdrawal. Taken together, these results clearly demonstrated that NENK has lower anesthetic and analgesic activity compared to ketamine, but has significant abuse liability.

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Psychological therapies for temporomandibular disorders (TMDs).

Temporomandibular disorders (TMDs) are a group of musculoskeletal disorders affecting the jaw. They are frequently associated with pain that can be difficult to manage and may become persistent (chronic). Psychological therapies aim to support people with TMDs to manage their pain, leading to reduced pain, disability and distress.

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Myofascial Pelvic Pain: Best Orientation and Clinical Practice. Position of the European Association of Urology Guidelines Panel on Chronic Pelvic Pain.

Despite the high prevalence of a myofascial pain component in chronic pelvic pain (CPP) syndromes, awareness and management of this component are lacking among health care providers.

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Chronic pain as a blind spot in the diagnosis of a depressed society. On the implications of the connection between depression and chronic pain for interpretations of contemporary society.

One popular description of current society is that it is a depressed society and medical evidence about depression's prevalence may well make such an estimation plausible. However, such normative-critical assessments surrounding depression have to date usually operated with a one-sided understanding of depression. This understanding widely neglects the various ways depression manifests as well as its comorbidities. This becomes evident at the latest when considering one of depression's most prominent and well-known comorbidities: chronic pain. Against this background, we aim in this article to substantiate our leading claim that the phenomenal interconnection between depression and chronic pain must be acknowledged in the global diagnosis of a depressive society. Thus, we argue here for a complementation of the dominant interpretation of a depressed society. This would support the overcoming of oversimplified images and estimations about depression in current society and further, help to recognize chronic pain properly on the larger scale of assessments that address society as a whole.

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Pain and Reorganization after Amputation: Is Interoceptive Prediction a Key?

There is an ongoing discussion on the relevance of brain reorganization following amputation for phantom limb pain. Recent attempts to provide explanations for seemingly controversial findings-specifically, maladaptive plasticity versus persistent functional representation as a complementary process-acknowledged that reorganization in the primary somatosensory cortex is not sufficient to explain phantom limb pain satisfactorily. Here we provide theoretical considerations that might help integrate the data reviewed and suppose a possible additional driver of the development of phantom limb pain-namely, an error in interoceptive predictions to somatosensory sensations and movements of the missing limb. Finally, we derive empirically testable consequences based on our considerations to guide future research.

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Comparative transcriptional analysis of satellite glial cell injury response.

Satellite glial cells (SGCs) tightly surround and support primary sensory neurons in the peripheral nervous system and are increasingly recognized for their involvement in the development of neuropathic pain following nerve injury. SGCs are difficult to investigate due to their flattened shape and tight physical connection to neurons and their rapid changes in phenotype and protein expression when cultured . Consequently, several aspects of SGC function under normal conditions as well as after a nerve injury remain to be explored. The recent advance in single cell RNA sequencing (scRNAseq) technologies has enabled a new approach to investigate SGCs. In this study we used scRNAseq to investigate SGCs from mice subjected to sciatic nerve injury. We used a meta-analysis approach to compare the injury response with that found in other published datasets.  Furthermore, we also used scRNAseq to investigate how cells from the dorsal root ganglion (DRG) change after 3 days in culture. From our meta-analysis of the injured conditions, we find that SGCs share a common signature of 18 regulated genes following sciatic nerve crush or sciatic nerve ligation, involving transcriptional regulation of cholesterol biosynthesis. We also observed a considerable transcriptional change when culturing SGCs, suggesting that some differentiate into a specialised state while others start resembling Schwann cell-like precursors. By using integrated analyses of new and previously published scRNAseq datasets, this study provides a consensus view of which genes are most robustly changed in SGCs after injury. Our results are available via the Broad Institute Single Cell Portal, so that readers can explore and search for genes of interest.

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Experiences of medical traumatic stress in parents of children with medical complexity.

Parents of children with medical complexity (CMC) experience high levels of stress and adverse mental health outcomes. Pediatric medical traumatic stress (PMTS) could be an important contributor that has not yet been explored. PMTS describes parents' reactions to their child's illness and medical treatment and can lead to post-traumatic stress symptoms. This is the first study to describe the experiences and impact of PMTS among parents of CMC.

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Roxadustat alleviates nitroglycerin-induced migraine in mice by regulating HIF-1α/NF-κB/inflammation pathway.

Sensitization of central pain and inflammatory pathways play essential roles in migraine, a primary neurobiological headache disorder. Since hypoxia-inducible factor-1α (HIF-1α) is implicated in neuroprotection and inflammation inhibition, herein we investigated the role of HIF-1α in migraine. A chronic migraine model was established in mice by repeated injection of nitroglycerin (10 mg/kg, i.p.) every other day for 5 total injections. In the prevention and acute experiments, roxadustat, a HIF-1α stabilizer, was orally administered starting before or after nitroglycerin injection, respectively. Pressure application measurement, and tail flick and light-aversive behaviour tests were performed to determine the pressure pain threshold, thermal nociceptive sensitivity and migraine-related light sensitivity. At the end of experiments, mouse serum samples and brain tissues were collected for analyses. We showed that roxadustat administration significantly attenuated nitroglycerin-induced basal hypersensitivity and acute hyperalgesia by improving central sensitization. Roxadustat administration also decreased inflammatory cytokine levels in serum and trigeminal nucleus caudalis (TNC) through NF-κB pathway. Consistent with the in vivo results showing that roxadustat inhibited microglia activation, roxadustat (2, 10, and 20 μM) dose-dependently reduced ROS generation and inflammation in LPS-stimulated BV-2 cells, a mouse microglia cell line, by inhibiting HIF-1α/NF-κB pathway. Taken together, this study demonstrates that roxadustat administration ameliorates migraine-like behaviours and inhibits central pain sensitization in nitroglycerin-injected mice, which is mainly mediated by HIF-1α/NF-κB/inflammation pathway, suggesting the potential of HIF-1α activators as therapeutics for migraine.

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Lessons from implementing the Australian National Action Plan for Endometriosis.

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Trends in opioid and non-opioid treatment for chronic non-cancer pain and cancer pain among privately insured adults in the United States, 2012-2019.

Recent clinical guidelines have emphasized non-opioid treatments in lieu of prescription opioids for chronic non-cancer pain, exempting cancer patients from these recommendations. In this study, we determine trends in opioid and non-opioid treatment among privately insured adults with chronic non-cancer pain (CNCP) or cancer. Using administrative claims data from IBM MarketScan Research Databases, we identified privately-insured adults who were continuously enrolled in insurance for at least one calendar year from 2012 to 2019. We identified individuals with CNCP diagnosis, defined as a diagnosis of arthritis, headache, low back pain, and/or neuropathic pain, and a individuals with cancer diagnosis in a calendar year. Outcomes included receipt of any opioid, non-opioid medication, or non-pharmacologic CNCP therapy and opioid prescribing volume, MME-per-day, and days' supply. Estimates were regression-adjusted for age, sex, and region. Between 2012 and 2019, the proportion of patients who received any opioid decreased across both groups (CNCP: 49.7 to 30.5%, p<0.01; cancer: 86.0 to 78.7%, p<0.01). Non-opioid pain medication receipt remained steady for individuals with CNCP (66.7 to 66.4%, p<0.01) and increased for individuals with cancer (74.4 to 78.8%, p<0.01), while non-pharmacologic therapy use rose among individuals with CNCP (62.4 to 66.1%, p<0.01). Among those prescribed opioids, there was a decrease in the receipt of at least one prescription with >90 MME/day (CNCP: 13.9% in 2012 to 4.9% in 2019, p<0.01; Cancer: 26.2% to 7.6%, p<0.01); >7 days of supply (CNCP: 56.3% to 30.7%, p <0.01; Cancer: 47.5% to 22.7%, p<0.01), the mean number of opioid prescriptions (CNCP: 5.2 to 3.9, p<0.01; Cancer: 4.0 to 2.7, p<0.01) and mean MME/day (CNCP: 49.9 to 38.0, p<0.01; Cancer: 62.4 to 44.7, p<0.01). Overall, from 2012-2019, opioid prescribing declined for CNCP and cancer, with larger reductions for patients with CNCP. For both groups, reductions in prescribed opioids outpaced increases in non-opioid alternatives.

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Rapid titration with oral sustained-release morphine plus subcutaneous morphine in a multi-center, randomized control study of cancer patients with moderate to severe cancer pain.

Pain is one of the most common concomitant symptoms among cancer patients. Pharmacologic agents are regarded as a cornerstone of cancer pain management. 'Dose titration' with short-acting morphine is widely accepted. Such a titration method is very complicated. The analgesic background establishment is often delayed. Titration based on sustained-release opioids is also recommended, but the onset of analgesic effect requires hours, whereas the rescue analgesia is always needed. This study evaluated the optimized morphine titration scheme with a simultaneous combination of sustained-release morphine and subcutaneous morphine.

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Extended Release of Bupivacaine from Temperature-Responsive Hydrogels Provides Multi-Day Analgesia for Postoperative Pain.

A local anesthetic that provides analgesia lasting at least three days could significantly improve postoperative pain management. This study evaluated the analgesic efficacy and safety of an extended-release formulation of bupivacaine based on the injectable hydrogel carrier poly(N-isopropylacrylamide-co-dimethylbutyrolactone acrylamide-co-Jeffamine M-1000 acrylamide) (PNDJ).

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Chronic Pain in Young People With Cerebral Palsy: Activity Limitations and Coping Strategies.

To describe the effect of chronic pain on the activities of children and adolescents with cerebral palsy, to describe coping strategies, and to examine associations between effect of pain on activities, coping strategies, and level of pain.

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Animal welfare assessment after severe traumatic brain injury in rats.

Severe traumatic brain injury (TBI) is a multifactorial injury process involving respiratory, cardiovascular and immune functions in addition to the brain. Thus, live animal models are needed to study the molecular, cellular and systemic mechanisms of TBI. The ethical use of laboratory animals requires that the benefits of approaches be carefully weighed against potential harm to animals. Welfare assessments adapted to severe TBI research are lacking. Here, we introduce a scoresheet to describe and monitor potential distress in animals, which includes general welfare (body weight, general appearance and spontaneous behaviour) and TBI-specific indices (respiratory function, pain, locomotor impairment, wound healing). Implementation of this scoresheet in Sprague-Dawley rats subjected to severe lateral fluid percussion TBI revealed a period of suffering limited to four days, followed by a recovery to normal welfare scores within 10-15 days, with females showing a worse impact than males. The scores indicate that animal suffering in this model is transitory compared with TBI consequences in humans. The scoresheet allows for the implementation of refinement measures including (1) analgesia during the initial period following TBI and (2) humane endpoints set (30% weight loss, score ≥90 and/or respiratory problems). This animal scoresheet tailored to TBI research provides a basis for further refinement of animal research paradigms aimed at understanding or treating the sequelae of severe TBI.

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A Delphi Study on the Management of Neuropathic Cancer Pain in Spain: The DOLNEO Study.

The objectives of this project were to assess the current situation and management of cancer-related neuropathic pain (CRNP) in Spain and to provide specific recommendations for the assessment, diagnosis and treatment of CRNP using a Delphi methodology.

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Supporting people with pain-related distress in primary care consultations: a qualitative study.

Low mood and distress are commonly reported by people who have persistent musculoskeletal (MSK) pain, which may be labelled as 'depression'. It is important to understand how pain-related distress is conceptualised and managed in primary care consultations.

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Automated scratching detection system for black mouse using deep learning.

The evaluation of scratching behavior is important in experimental animals because there is significant interest in elucidating mechanisms and developing medications for itching. The scratching behavior is classically quantified by human observation, but it is labor-intensive and has low throughput. We previously established an automated scratching detection method using a convolutional recurrent neural network (CRNN). The established CRNN model was trained by white mice (BALB/c), and it could predict their scratching bouts and duration. However, its performance in black mice (C57BL/6) is insufficient. Here, we established a model for black mice to increase prediction accuracy. Scratching behavior in black mice was elicited by serotonin administration, and their behavior was recorded using a video camera. The videos were carefully observed, and each frame was manually labeled as scratching or other behavior. The CRNN model was trained using the labels and predicted the first-look videos. In addition, posterior filters were set to remove unlikely short predictions. The newly trained CRNN could sufficiently detect scratching behavior in black mice (sensitivity, 98.1%; positive predictive rate, 94.0%). Thus, our established CRNN and posterior filter successfully predicted the scratching behavior in black mice, highlighting that our workflow can be useful, regardless of the mouse strain.

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Machine learning-based improvement of an online rheumatology referral and triage system.

Rheport is an online rheumatology referral system allowing automatic appointment triaging of new rheumatology patient referrals according to the respective probability of an inflammatory rheumatic disease (IRD). Previous research reported that Rheport was well accepted among IRD patients. Its accuracy was, however, limited, currently being based on an expert-based weighted sum score. This study aimed to evaluate whether machine learning (ML) models could improve this limited accuracy.

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Effective therapies for sickle cell disease: are we there yet?

Sickle cell disease (SCD) is a common genetic blood disorder associated with acute and chronic pain, progressive multiorgan damage, and early mortality. Recent advances in technologies to manipulate the human genome, a century of research and the development of techniques enabling the isolation, efficient genetic modification, and reimplantation of autologous patient hematopoietic stem cells (HSCs), mean that curing most patients with SCD could soon be a reality in wealthy countries. In parallel, ongoing research is pursuing more facile treatments, such as in-vivo-delivered genetic therapies and new drugs that can eventually be administered in low- and middle-income countries where most SCD patients reside.

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Skin Treatment with Detergent Induces Dermatitis with H1-Antihistamine-Refractory Itch and Upregulates IL-4 and Th17/Th22 Cytokine Gene Expression in C57BL/6 Mice.

Repeated skin contact to detergents causes chronic irritant contact dermatitis (ICD) associated with itch sensation and eczema. However, the mechanisms of detergent-induced ICD are poorly understood. Here, we established a new murine model of detergent-induced ICD with H1-antihistamine-refractory itch.

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Disparities in Prehospital Non-Traumatic Pain Management.

While prior research has identified racial disparities in prehospital analgesia for traumatic pain, little is known about non-traumatic pain. Using a national prehospital dataset, we sought to evaluate for racial and ethnic disparities in analgesia given by EMS for non-traumatic pain.

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Muscle degeneration in chronic massive rotator cuff tears of the shoulder: Addressing the real problem using a graphene matrix.

Massive rotator cuff tears (MRCTs) of the shoulder cause disability and pain among the adult population. In chronic injuries, the tendon retraction and subsequently the loss of mechanical load lead to muscle atrophy, fat accumulation, and fibrosis formation over time. The intrinsic repair mechanism of muscle and the successful repair of the torn tendon cannot reverse the muscle degeneration following MRCTs. To address these limitations, we developed an electroconductive matrix by incorporating graphene nanoplatelets (GnPs) into aligned poly(l-lactic acid) (PLLA) nanofibers. This study aimed to understand 1) the effects of GnP matrices on muscle regeneration and inhibition of fat formation in vitro and 2) the ability of GnP matrices to reverse muscle degenerative changes in vivo following an MRCT. The GnP matrix significantly increased myotube formation, which can be attributed to enhanced intracellular calcium ions in myoblasts. Moreover, the GnP matrix suppressed adipogenesis in adipose-derived stem cells. These results supported the clinical effects of the GnP matrix on reducing fat accumulation and muscle atrophy. The histological evaluation showed the potential of the GnP matrix to reverse muscle atrophy, fat accumulation, and fibrosis in both supraspinatus and infraspinatus muscles at 24 and 32 wk after the chronic MRCTs of the rat shoulder. The pathological evaluation of internal organs confirmed the long-term biocompatibility of the GnP matrix. We found that reversing muscle degenerative changes improved the morphology and tensile properties of the tendon compared with current surgical techniques. The long-term biocompatibility and the ability of the GnP matrix to treat muscle degeneration are promising for the realization of MRCT healing and regeneration.

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An experimental study to inform adoption of mindfulness-based stress reduction in chronic low back pain.

Chronic low back pain is a common and sometimes disabling condition, and mindfulness-based stress reduction is recommended as a first line of therapy. This study tested whether different descriptions of mindfulness training altered based on influential intervention characteristics increased adoption intentions.

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Preoperative Ultrasound-Guided Percutaneous Cryoneurolysis for the Treatment of Pain following Mastectomy: A Randomized, Participant- and Observer-Masked, Sham-Controlled Study.

Ultrasound-guided percutaneous cryoneurolysis is an analgesic technique in which a percutaneous probe is used to reversibly ablate a peripheral nerve(s) using exceptionally low temperature, and has yet to be evaluated with randomized, controlled trials. Pain following mastectomy can be difficult to treat, and we hypothesized that the severity of surgically-related pain would be lower on postoperative day 2 with the addition of cryoanalgesia as compared with patients receiving solely standard-of-care treatment.

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Stigma and Chronic Pain.

Stigma is defined by the World Health Organization (WHO) as "a mark of shame, disgrace or disapproval that results in an individual being rejected, discriminated against and excluded from participating in a number of different areas of society". Extensive literature searches have documented stigma in the context of health. Among the physical health conditions that are associated with stigma, chronic pain deserves particular attention. Stigma experienced by individuals with chronic pain affects their entire life. Literature identifies multiple dimensions or types of stigma, including public stigma, structural stigma and internalized stigma. Recent literature supports the biopsychosocial model of pain, according to which biological, psychological and sociocultural variables interact in a dynamic manner to shape an individual's response to chronic pain. Chronic pain affects a higher proportion of women than men around the world. There is an inadequate education of health care professionals regarding pain assessment and their insecurity to manage patients with chronic pain. A first-line intervention strategy could be to promote pain education and to expand knowledge and assessment of chronic pain, as recently highlighted for headache disorders, paradigmatically for resistant or refractory migraine, whose diagnosis, without an adequate education to understand the possible fluctuations of the disease, may have profound psychological implications with the idea of insolvability and contribute to stigmatizing the patient.

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Effects of treatment with a carbon monoxide donor and an activator of heme oxygenase 1 on the nociceptive, apoptotic and/or oxidative alterations induced by persistent inflammatory pain in the central nervous system of mice.

The activation of heme oxygenase 1 (HO-1)/carbon monoxide (CO) inhibits chronic inflammatory pain, but its role in the central nervous system (CNS) is not entirely known. We evaluated whether the treatment with an HO-1 inducer, cobalt protoporphyrin IX (CoPP), or a CO-releasing molecule, tricarbonyldichlororuthenium(II)dimer (CORM-2), modulates the nociceptive, apoptotic and/or oxidative responses provoked by persistent inflammatory pain in the CNS. In C57BL/6 male mice with peripheral inflammation caused by complete Freund's adjuvant (CFA), we assessed the effects of CORM-2 and CoPP on the expression of protein kinase B (Akt), the apoptotic protein BAX, and the antioxidant enzymes HO-1 and NADPH quinone oxidoreductase 1 (NQO1) in the periaqueductal gray matter (PAG), amygdala (AMG), ventral hippocampus (VHPC) and medial septal area (MSA). Our results showed that the increased expression of p-Akt caused by peripheral inflammation in the four analyzed brain areas was reversed by CORM-2 and CoPP therapies. Both treatments also normalized the upregulation of BAX induced by CFA on the VHPC and MSA. Oxidative stress, demonstrated with the decreased expression of HO-1 on the PAG and AMG, was normalized in CORM-2 and CoPP treated animals. CoPP also increased the expression of HO-1 on VHPC, and both treatments up-regulated the NQO1 levels on the PAG of CFA-injected animals. In conclusion, both CORM-2 and CoPP treatments inhibited the nociceptive and apoptotic responses generated by peripheral inflammation and/or potentiated the antioxidant responses in several brain areas revealing the new modulatory effects of these treatments in the CNS of animals with chronic inflammatory pain.

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Virtual reality and motor control exercises to treat chronic neck pain: A randomized controlled trial.

To compare the effects of virtual reality (VR) and motor control (MC) exercises.

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Ketogenic diet in refractory migraine: possible efficacy and role of ketone bodies-a pilot experience.

Refractory migraine is a particularly disabling form of chronic migraine, unresponsive to multiple prophylactic strategies. Ketogenic diet (KD) is useful to treat migraine but poorly tested for refractory migraine.

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Serum biomarkers in prednisolone treated hand osteoarthritis patients.

To investigate whether biomarkers are modulated by prednisolone treatment in patients with hand osteoarthritis (OA) and whether they can predict response to prednisolone.

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Small fiber neuropathies: expanding their etiologies.

Several conditions have been associated with the development of small fiber neuropathy (SFN). The list of metabolic, immune-mediated, infectious, toxic, drugs-related, and hereditary conditions is still growing and various hypotheses are made about the underlying pathophysiological mechanisms. Understanding these processes is important to provide new targets for treatment. In addition, the specific SFN phenotype can provide direction for the underlying etiology. This review discusses the latest developments concerning the expanding etiologies in SFN.

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Mindfulness-Based Interdisciplinary Pain Management Program for Complex Polymorbid Pain in Veterans: A Randomized Clinical Trial.

To evaluate the effects of interdisciplinary pain management on pain-related disability and opioid reduction in polymorbid pain patients with two or more comorbid psychiatric conditions.

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Pain Allaying Epalrestat-Loaded Lipid Nanoformulation for the Diabetic Neuropathic Pain Interventions: Design, Development and Animal Study.

Diabetic peripheral neuropathy (DPN) is the most common complication of diabetes mellitus. Epalrestat, an aldose reductase inhibitor, has been approved for clinical therapy for diabetic peripheral neuropathic pain. In the present study, solid lipid-based nanoparticles are used for oral administration of epalrestat (E-SLN) and evaluated against diabetic neuropathic pain in a rat model.

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Medicinal Cannabis for the Treatment of Chronic Refractory Pain: An Investigation of the Adverse Event Profile and Health-Related Quality of Life Impact of an Oral Formulation.

Medicinal cannabis is prescribed in Australia for patients with chronic refractory pain conditions. However, measures of safety and effectiveness of different cannabinoids are lacking. We designed an observational study to capture effectiveness, adverse events (AEs), and health-related quality of life (HRQoL) measures in patients prescribed an oral medicinal cannabis formulation at Cannabis Access Clinics through the Cannabis Access Clinics Observational study (CACOS).

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Psychologic Impact of Chronic Orofacial Pain: A Critical Review.

To explore the prevalence of clinically significant anxiety and depression in adult patients with chronic orofacial pain (COFP) conditions.

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Epigenetic modulation of visceral nociception.

Epigenetics is a process that alters gene activity or phenotype without any changes in the underlying DNA sequence or genotype. These biological changes may have deleterious effects and can lead to various human diseases. Ongoing research is continuing to illuminate the role of epigenetics in a variety of pathophysiologic processes. Several categories of epigenetic mechanisms have been studied including chromatin remodeling, DNA methylation, histone modification, and non-coding RNA mechanisms. These epigenetic changes can have a long-term effect on gene expression without any underlying changes in the DNA sequences. The underlying pathophysiology of disorders of brain-gut interaction and stress-induced visceral pain are not fully understood and the role of epigenetic mechanisms in these disorders are starting to be better understood. Current work is underway to determine how epigenetics plays a role in the neurobiology of patients with chronic visceral pain and heightened visceral nociception. More recently, both animal models and human studies have shown how epigenetic regulation modulates stress-induced visceral pain. While much more work is needed to fully delineate the mechanistic role of epigenetics in the neurobiology of chronic visceral nociception, the current study by Louwies et al., in Neurogastroenterology and Motility provides additional evidence supporting the involvement of epigenetic alterations in the central nucleus of the amygdala in stress-induced visceral hypersensitivity in rodents.

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Dopamine receptor D2 regulates GLUA1-containing AMPA receptor trafficking and central sensitization through the PI3K signaling pathway in a male rat model of chronic migraine.

The pathogenesis of chronic migraine remains unresolved. Recent studies have affirmed the contribution of GLUA1-containing AMPA receptors to chronic migraine. The dopamine D2 receptor, a member of G protein-coupled receptor superfamily, has been proven to have an analgesic effect on pathological headaches. The present work investigated the exact role of the dopamine D2 receptor in chronic migraine and its effect on GLUA1-containing AMPA receptor trafficking.

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Quality assessment and relevant clinical impact of randomized controlled trials on chronic prostatitis/chronic pelvic pain syndrome.

This study evaluated the quality of randomized controlled trials (RCTs) on chronic prostatitis/chronic pelvic pain syndrome (CP/CPPS).

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Challenges and complexities in designing cluster headache prevention clinical trials: A narrative review.

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Assessing pain after cancer treatment.

Chronic pain is common following cancer treatment. This is a brief discussion of pain assessment after cancer treatment.

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Differences in opioid prescription rates between patients with musculoskeletal disorders enrolled in coordinated ambulatory healthcare and patients receiving usual care: a retrospective observational cohort study.

To compare opioid prescription rates between patients enrolled in coordinated ambulatory care and patients receiving usual care.

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What is the purpose of the diagnostic criterion for fibromyalgia?

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Editorial: Calcitonin Gene-Related Peptide: Novel Biology and Treatments.

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Resilience as a protective factor in face of pain symptomatology, disability and psychological outcomes in adult chronic pain populations: a scoping review.

Patients suffering from chronic pain experience significant disability and disease burden. Resilience has been understood to be a protective factor in face of adversity, eventually contributing to positive outcomes. As such, the current review sought to summarize the existing literature focusing on the roles of resilience in relation to pain phenomenology, pain outcomes (including function and mental health), amongst relevant clinical correlates in a bid to promote holistic management of debilitating chronic pain conditions from a resilience-oriented psychotherapeutic approach as an adjunct to pharmacological treatment.

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Application of the novel Nalu™ Neurostimulation System for peripheral nerve stimulation.

Peripheral nerve stimulation is an established treatment modality for chronic neuropathic pain. Over the last decade, with the advent of innovative devices and delivery platforms, peripheral nerve stimulation has evolved from invasive open surgeries to image-guided, minimally invasive percutaneous procedures. The authors hereby present a novel device, the Nalu™ Neurostimulation System (Nalu Medical, CA, USA), which has established its advantages in providing predictable and reliable peripheral nerve stimulation therapy for chronic neuropathic pain management. This novel device is effective in treating chronic pain conditions such as post-herniorrhaphy pain syndrome, intercostal neuralgia, post-laminectomy syndrome, and complex regional pain syndrome and holds great promise for the treatment of peripheral neuropathic pain.

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OREX-1038: a potential new treatment for pain with low abuse liability and limited adverse effects.

Drugs targeting mu opioid receptors are the mainstay of clinical practice for treating moderate-to-severe pain. While they can offer excellent analgesia, their use can be limited by adverse effects, including constipation, respiratory depression, tolerance, and abuse liability. Multifunctional ligands acting at mu opioid and nociceptin/orphanin FQ peptide receptors might provide antinociception with substantially improved adverse-effect profiles. This study explored one of these ligands, OREX-1038 (BU10038), in several assays in rodents and nonhuman primates. Binding and functional studies confirmed OREX-1038 to be a low-efficacy agonist at mu opioid and nociceptin/orphanin FQ peptide receptors and an antagonist at delta and kappa opioid receptors with selectivity for opioid receptors over other proteins. OREX-1038 had long-acting antinociceptive effects in postsurgical and complete Freund's adjuvant (CFA)-induced thermal hyperalgesia assays in rats and a warm water tail-withdrawal assay in monkeys. OREX-1038 was active for at least 24 h in each antinociception assay, and its effects in monkeys did not diminish over 22 days of daily administration. This activity was coupled with limited effects on physiological signs (arterial pressure, heart rate, and body temperature) and no evidence of withdrawal after administration of naltrexone or discontinuation of treatment in monkeys receiving OREX-1038 daily. Over a range of doses, OREX-1038 was only transiently self-administered, which diminished rapidly to nonsignificant levels; overall, both OREX-1038 and buprenorphine maintained less responding than remifentanil. These results support the concept of dual mu and nociceptin/orphanin FQ peptide receptor partial agonists having improved pharmacological profiles compared with opioids currently used to treat pain.

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Effects on pain and cognition of transcranial direct current stimulation over the dorsolateral prefrontal cortex in women with chronic migraine.

We compared the effects of one versus two daily sessions of anodal transcranial direct current stimulation (a-tDCS) delivered to the left dorsolateral prefrontal cortex (DLPFC) for 10 days in a cohort of 30 women (mean age 28.0±6.92) with chronic migraine (CM, disease duration: 37.8±48.41 month). Participants were randomly allocated to three groups: a-tDCS 1-s Group received one daily a-tDCS session; a-tDCS 2-s Group received two daily a-tDCS sessions; Group SHAM received one daily session with a simulated (placebo) current. All participants were assessed before, after and one month after treatment, using the Migraine Disability Assessment, Montreal Cognitive Assessment, d2 Test of Attention, Trail Making Test (part B), Sequence of Letters and Numbers of the Wechsler Adult Intelligence Scale – III, and Nine Hole Peg Test. We found no difference between groups in the cognitive measures and motor dexterity. However, after treatment, a significant decrease in migraine-related disability was found for the a-tDCS 1-s Group. For all variables, no cumulative effects were observed in a-tDCS 2-s compared to the a-tDCS 1-s Group. The study findings provide preliminary results for future clinical trials designed to compare different intervals between tDCS sessions in CM.

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Effects of selective inhibition of prostaglandin E2 receptors EP2 and EP4 on the miRNA profile in endometriosis.

Endometriosis is an estrogen-dependent, progesterone-resistant, chronic inflammatory gynecological disease of reproductive-age women. Two major clinical symptoms of endometriosis are chronic pelvic pain and infertility, which profoundly affect the quality of life in women. Current hormonal therapies to induce a hypoestrogenic state are unsuccessful because of undesirable side effects, reproductive health concerns, and failure to prevent disease recurrence. Prostaglandin E (PGE) plays an important role in the survival and growth of endometriotic lesions. MicroRNAs (miRNAs) are small, noncoding RNAs that control gene expressions through multiple mechanisms and have important roles in the pathogenesis of endometriosis. The objective of the present study is to determine the effects of pharmacological inhibition of PGE receptors, EP2 and EP4, on miRNA profile in endometriosis. The novel results collectively indicate that inhibition of PGE-EP2/EP4 signaling regulated several miRNA clusters associated with cell adhesion, migration, invasion, survival and growth in cell-specific and the chromosome-specific manner and reverses the epigenetic silencing of proapoptotic miRNAs 15a and 34c in the human endometriotic epithelial and stromal cells and experimental endometriotic lesions. Thus, selective inhibition of EP2/EP4 receptors could emerge as a potential nonsteroidal therapy for endometriosis.

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Uncovering a new route to pain therapy.

High-voltage-activated calcium channels (HVACCs) are promising targets for developing analgesics given their roles in controlling synaptic transmission, neuronal excitability and neuropeptide release in primary nociceptive neurons. Despite previous efforts in developing HVACCs inhibitors of various drug modalities, it remains undetermined whether targeting HVACCs directly by a gene therapy approach could lead to pain alleviation in vivo. To test this, Sun and colleagues adopted a post-translational ubiquitination-based knockdown method targeting HVACCs in primary sensory neurons. They showed ablation of HVACC currents in a subset of primary sensory neurons, dampened hyperexcitability of sensory neurons after nerve injury and reduced pain behavior with no apparent adverse effects [1]. The results open the possibility of targeting ion channels with ubiquitination-based knockdown as a promising gene therapy candidate for pain treatment in future clinical studies.

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GPR171 activation regulates morphine tolerance but not withdrawal in a test-dependent manner in mice.

A newly deorphanized G protein-coupled receptor, GPR171, is found to be highly expressed within the periaqueductal gray, a pain-modulating region in the brain. Our recent research has shown that a GPR171 agonist increases morphine antinociception in male mice and opioid signaling in vitro. The objective of this study was to evaluate the effects of combination treatment in females as well as whether chronic treatment can be used without exacerbating morphine-induced tolerance and withdrawal in female and male mice. Our results demonstrate that activation of GPR171 with an agonist attenuates morphine tolerance in both female and male mice on the tail-flick test, but not the hotplate test. Importantly, the GPR171 agonist in combination with morphine does not exacerbate morphine-induced tolerance and withdrawal during long-term morphine treatment. Taken together, these data suggest that the GPR171 agonist may be combined with morphine to maintain antinociception while reducing the dose of morphine and therefore reducing side effects and abuse liability. The outcome of this study is clearly an important step toward understanding the functional interactions between opioid receptors and GPR171 and developing safer therapeutics for long-term pain management.

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Patient-controlled intravenous analgesia with opioids after thoracoscopic lung surgery: a randomized clinical trial.

Opioids remain the mainstream therapy for post-surgical pain. The choice of opioids administered by patient-controlled intravenous analgesia (PCIA) for thoracoscopic lung surgery is unclear. This study compared 3 opioid analgesics for achieving satisfactory analgesia with minimal emesis (SAME).

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Interaction Between Ropivacaine and a Self-Assembling Peptide: A Nanoformulation for Long-Acting Analgesia.

Ropivacaine as a conventional local anesthetic has been used more and more frequently in the treatment of postoperative pain, but its analgesic effect can only last for several hours. In order to fulfill the clinic requirement for long-term analgesia, a long-acting ropivacaine nanocrystal formulation was fabricated through the interaction between ropivacaine and a self-assembling peptide.

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Dimethyl Itaconate Attenuates CFA-Induced Inflammatory Pain the NLRP3/ IL-1β Signaling Pathway.

Itaconate plays a prominent role in anti-inflammatory effects and has gradually been ushered as a promising drug candidate for treating inflammatory diseases. However, its significance and underlying mechanism for inflammatory pain remain unexplored. In the current study, we investigated the effects and mechanisms of Dimethyl Itaconate (DI, a derivative of itaconate) on Complete Freund's adjuvant (CFA)-induced inflammatory pain in a rodent model. Here, we demonstrated that DI significantly reduced mechanical allodynia and thermal hyperalgesia. The DI-attenuated neuroinflammation was evident with the amelioration of infiltrative macrophages in peripheral sites of the hind paw and the dorsal root ganglion. Concurrently, DI hindered the central microglia activation in the spinal cord. Mechanistically, DI inhibited the expression of pro-inflammatory factors interleukin (IL)-1β and tumor necrosis factor alpha (TNF-α) and upregulated anti-inflammatory factor IL-10. The analgesic mechanism of DI was related to the downregulation of the nod-like receptor protein 3 (NLRP3) inflammasome complex and IL-1β secretion. This study suggested possible novel evidence for prospective itaconate utilization in the management of inflammatory pain.

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Epigenetic regulation and T-cell responses in endometriosis – something other than autoimmunity.

Endometriosis is defined as the presence of endometrial-like glands and stroma located outside the uterine cavity. This common, estrogen dependent, inflammatory condition affects up to 15% of reproductive-aged women and is a well-recognized cause of chronic pelvic pain and infertility. Despite the still unknown etiology of endometriosis, much evidence suggests the participation of epigenetic mechanisms in the disease etiopathogenesis. The main rationale is based on the fact that heritable phenotype changes that do not involve alterations in the DNA sequence are common triggers for hormonal, immunological, and inflammatory disorders, which play a key role in the formation of endometriotic foci. Epigenetic mechanisms regulating T-cell responses, including DNA methylation and posttranslational histone modifications, deserve attention because tissue-resident T lymphocytes work in concert with organ structural cells to generate appropriate immune responses and are functionally shaped by organ-specific environmental conditions. Thus, a failure to precisely regulate immune cell transcription may result in compromised immunological integrity of the organ with an increased risk of inflammatory disorders. The coexistence of endometriosis and autoimmunity is a well-known occurrence. Recent research results indicate regulatory T-cell (Treg) alterations in endometriosis, and an increased number of highly active Tregs and macrophages have been found in peritoneal fluid from women with endometriosis. Elimination of the regulatory function of T cells and an imbalance between T helper cells of the Th1 and Th2 types have been reported in the endometria of women with endometriosis-associated infertility. This review aims to present the state of the art in recognition epigenetic reprogramming of T cells as the key factor in the pathophysiology of endometriosis in the context of T-cell-related autoimmunity. The new potential therapeutic approaches based on epigenetic modulation and/or adoptive transfer of T cells will also be outlined.

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Efficacy and safety of intravenous acetaminophen (2 g/day) for reducing opioid consumption in Chinese adults after elective orthopedic surgery: A multicenter randomized controlled trial.

Acetaminophen is an important component of a multimodal analgesia strategy to reduce opioid consumption and pain intensity after an orthopedic surgery. The opioid-sparing efficacy of intravenous acetaminophen has been established at a daily dose of 4 g. However, it is still unclear for the daily dose of 2 g of acetaminophen, which is recommended by the China Food and Drug Administration Center for Drug Evaluation, in terms of its efficacy and safety. This study aimed to evaluate the efficacy and safety of intravenous acetaminophen at a daily dose of 2 g for reducing opioid consumption and pain intensity after orthopedic surgery. In this multicenter, randomized, double-blind, placebo-controlled phase III trial, 235 patients who underwent orthopedic surgery were randomly assigned to receive intravenous acetaminophen 500 mg every 6 h or placebo. Postoperative morphine consumption, pain intensity at rest and during movement, and adverse events were analysed. For the mean (standard deviation) morphine consumption within 24 h after surgery, intravenous acetaminophen was superior to placebo both in the modified intention-to-treat analysis [8.7 (7.7) mg vs. 11.2 (9.2) mg] in the acetaminophen group and the placebo group, respectively. Difference in means: 2.5 mg; 95% confidence interval, 0.25 to 4.61; = 0.030), and in the per-protocol analysis (8.3 (7.0) mg and 11.7 (9.9) mg in the acetaminophen group and the placebo group, respectively. Difference in means: 3.4 mg; 95% confidence interval: 1.05 to 5.77; = 0.005). The two groups did not differ significantly in terms of pain intensity and adverse events. Our results suggest that intravenous acetaminophen at a daily dose of 2 g can reduce morphine consumption by Chinese adults within the first 24 h after orthopedic surgery, but the extent of reduction is not clinically relevant. : [ClinicalTrials.gov], identifier [NCT02811991].

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Serine racemase interaction with N-methyl-D-aspartate receptors antagonist reveals potential alternative target of chronic pain treatment: Molecular docking study.

Serine racemase (SR) catalyzes L-serine racemization to activate the N-methyl-D-aspartate receptor (NMDAR). NMDAR activation is associated with the progression of acute-to-chronic neuropathic pain. This study aimed to investigate NMDAR antagonist interactions with SR to obtain potential chronic pain target therapy. Several NMDAR antagonist drugs were obtained from the drug bank, and malonate was used as a control inhibitor. Ligands were prepared using the open babel feature on PyRx. The SR structure was obtained from Protein data bank (PDB) (3l6B) and then docked with ligands using the AutoDock Vina. Haloperidol had a lower binding affinity than malonate and other ligands. Ethanol had the highest binding affinity than other drugs but could bind to the Adenosine triphosphate (ATP)-binding domain. Haloperidol is bound to reface that function for reprotonation in racemization reaction to produce D-serine. Halothane bond with Arg135 residues aligned negatively charged substrates to be reprotonated properly by reface. Tramadol is bound to amino acid residues in the triple serine loop, which determines the direction of the SR reaction. Several NMDAR antagonists such as haloperidol, halothane, ethanol, and tramadol bind to SR in the specific binding site. It reveals that SR potentially becomes an alternative target for chronic pain treatment.

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Nitidine Chloride Alleviates Inflammation and Cellular Senescence in Murine Osteoarthritis Through Scavenging ROS.

Osteoarthritis (OA) is one of the most common chronic musculoskeletal disorder worldwide, representing a major source of disability, pain and socioeconomic burden. Yet the effective pharmaceutical treatments applied in the clinical works are merely symptomatic management with uncertainty around their long-term safety and efficacy, namely no drugs currently are capable of modulating the biological progression of OA. Here, we identified the potent anti-inflammatory as well as anti-oxidative properties of Nitidine Chloride (NitC), a bioactive phytochemical alkaloid extracted from natural herbs, in IL-1β-treated rat articular chondrocytes (RACs), LPS-stimulated RAW 264.7 and rat osteoarthritic models . We demonstrated NitC remarkably inhibited the production of inflammatory mediators including COX2 and iNOS, suppressed the activation of MAPK and NF-κB cell signaling pathway and reduced the expression of extracellular matrix (ECM) degrading enzymes including MMP3, MMP9 and MMP13 in IL-1β-treated RACs. Several emerging bioinformatics tools were performed to predict the underlying mechanism, the result of which indicated the potential reactive oxygen species (ROS) clearance potential of NitC. Further, NitC exhibited its anti-oxidative potential through ameliorating cellular senescence in IL-1β-treated RACs and decreasing NLRP3 inflammasomes activation in LPS-stimulated RAW 264.7 scavenging ROS. Additionally, X-ray, micro-CT and other experiments demonstrated that intra-articular injection of NitC significantly alleviated the cartilage erosion, ECM degradation and subchondral alterations in OA progression. In conclusion, the present study reported the potent anti-inflammatory and anti-oxidative potential of NitC in OA biological process, providing a promising therapeutic agent for OA management.

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At Least 5-Year Outcomes of Whiplash-Induced Chronic Neck Pain Following Response to Intra-Articular Facet Joint Corticosteroid Injection.

To investigate whether the response to intra-articular facet joint corticosteroid injection can determine the long-term prognosis (at least 5 years after injury) of whiplash injury-related neck pain sustained 3-12 months after injury.

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Long Non-Coding RNA and mRNA Profiles in the Spinal Cord of Rats with Resiniferatoxin-Induced Neuropathic Pain.

The ultrapotent transient receptor potential vanilloid 1 (TRPV1) agonist resiniferatoxin (RTX) induces small-fiber sensory neuropathy, which has been widely used model of postherpetic neuralgia to study mechanisms of neuropathic pain and new analgesics. The long non-coding RNA (lncRNA) and mRNA expression profiles in spinal dorsal horn tissues of rats six weeks after RTX injection to identify new RNAs related to neuropathic pain.

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“I Still Suffer Every Second of Every Day”: A Qualitative Analysis of the Challenges of Living with Chronic Orofacial Pain.

Chronic orofacial pain is prevalent and debilitating. Psychological and social factors place a heavy burden on this population but are often overlooked. Here, we offer the first comprehensive qualitative conceptualization of the challenges of living with chronic orofacial pain through a biopsychosocial perspective to inform multifaceted care for this population.

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The Current View on the Paradox of Pain in Autism Spectrum Disorders.

Autism spectrum disorder (ASD) is a neurodevelopmental disorder, which affects 1 in 44 children and may cause severe disabilities. Besides socio-communicational difficulties and repetitive behaviors, ASD also presents as atypical sensorimotor function and pain reactivity. While chronic pain is a frequent co-morbidity in autism, pain management in this population is often insufficient because of difficulties in pain evaluation, worsening their prognosis and perhaps driving higher mortality rates. Previous observations have tended to oversimplify the experience of pain in autism as being insensitive to painful stimuli. Various findings in the past 15 years have challenged and complicated this dogma. However, a relatively small number of studies investigates the physiological correlates of pain reactivity in ASD. We explore the possibility that atypical pain perception in people with ASD is mediated by alterations in pain perception, transmission, expression and modulation, and through interactions between these processes. These complex interactions may account for the great variability and sometimes contradictory findings from the studies. A growing body of evidence is challenging the idea of alterations in pain processing in ASD due to a single factor, and calls for an integrative view. We propose a model of the pain cycle that includes the interplay between the molecular and neurophysiological pathways of pain processing and it conscious appraisal that may interfere with pain reactivity and coping in autism. The role of social factors in pain-induced response is also discussed. Pain assessment in clinical care is mostly based on subjective rather than objective measures. This review clarifies the strong need for a consistent methodology, and describes innovative tools to cope with the heterogeneity of pain expression in ASD, enabling individualized assessment. Multiple measures, including self-reporting, informant reporting, clinician-assessed, and purely physiological metrics may provide more consistent results. An integrative view on the regulation of the pain cycle offers a more robust framework to characterize the experience of pain in autism.

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First-in-human study to evaluate the safety, tolerability and pharmacokinetics of a novel analgesic and antipyretic drug with structural similarity to acetaminophen.

JNJ-10450232 (NTM-006) is a new molecular entity that comprises structural similarities to acetaminophen and provides comparable analgesia in animals and humans without causing the hepatotoxicity associated with acetaminophen overdose in preclinical models. This double-blind, placebo-controlled, first-in-human study evaluated the safety, tolerability, and pharmacokinetics of JNJ-10450232 (NTM-006) following single (50-6000 mg) and multiple (250-2500 mg twice daily for 8 days) doses in healthy male volunteers. JNJ-10450232 (NTM-006) was absorbed within 1-3 h, except at high doses at which C was delayed and bimodal, while increases in AUC were more than dose proportional. CL/F and Vd/F decreased approximately 3-fold with increasing single doses up to 6000 mg and multiple doses up to 1000 mg, resulting in similar t values that ranged from 8-10 h across doses. JNJ-10450232 (NTM-006) was generally safe and well tolerated, and no dose-limiting toxicities were observed. Transient increases in indirect bilirubin were noted at post-baseline timepoints due to UGT1A1 inhibition, without any evidence of adverse hepatic effects. Macular rash and generalized erythema were the most common drug-related adverse events after multiple doses.

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FGF 10 Inhibited Spinal Microglial Activation in Neuropathic Pain via PPAR-γ/NF-κB Signaling.

Overactivated microglia in the spinal cord leads to neuropathic pain sensitivity. The FGF 10, a Fibroblast Growth Factor (FGFs) that is prevalent in neurons, has been demonstrated to suppress microglial polarization. The objective of this study was to investigate the role of FGF 10 in neuropathic pain and the underlying regulatory mechanisms. Immunofluorescence staining and western blot detection revealed that FGF 10 expression was upregulated in the ipsilateral spinal dorsal horn of Spared Nerve Injury (SNI) rat models and was mainly detected in neurons and microglia. To test the anti-microgliosis actions of FGF 10, SNI rats were intrathecally administered with different concentrations of recombinant FGF 10. Behavioral tests and immunostaining results showed that FGF 10 relieved hyperalgesia in SNI rats and inhibited microglial activity in the ipsilateral spinal dorsal horn in a dose-dependent manner. Besides, BV2 cells were cultured and treated with LPS to activate microglia to explore the underlying mechanisms of FGF 10-induced analgesic effects in vitro. As a result, FGF 10 administration suppressed the LPS-induced microglial augmentation in a dose-dependent manner, followed by increased PPAR-γ and decreased NFκB phosphorylation (p-NFκB) levels. Moreover, PPAR-γ agonist (pioglitazone) and antagonist (GW9662) were administrated into spinal cords of SNI rats, revealing that pioglitazone had similar anti-nociceptive and anti-microglial effects to FGF 10. Conversely, GW9662 reversed all beneficial effects of FGF 10 on SNI rats. In addition, phosphorylated levels of NFκB were reduced by pioglitazone or FGF 10 treatment but raised by GW9662 administration in FGF 10-treated SNI rats. Our findings show that FGF 10 has analgesic effects in rats after peripheral nerve injury and justify the role of PPAR-γ/NFκB signaling in FGF 10-regulated anti-microgliosis.

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The practical limits of high-quality magnetic resonance imaging for the diagnosis and classification of trigeminal neuralgia.

Neurovascular compression (NVC) has been the primary hypothesis for the underlying mechanism of classical trigeminal neuralgia (TN). However, a substantial body of literature has emerged highlighting notable exceptions to this hypothesis. The purpose of this study is to assess the reliability and diagnostic accuracy of high resolution, high contrast MRI-determined neurovascular contact for TN.

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Psychological management of patients with chronic prostatitis/chronic pelvic pain syndrome (CP/CPPS): a systematic review.

Chronic prostatitis/chronic pelvic pain syndrome (CP/CPPS) is a complex condition. Despite recommendations for the inclusion of non-pharmacological treatment in the management of CP/CPPS, the focus has predominantly been on the inclusion of physical therapies with minimal discussion of psychological interventions. Therefore, this systematic review aimed to evaluate peer-reviewed studies of psychological interventions for men with CP/CPPS to determine their therapeutic efficacy and quality of intervention.

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Effects of psychosocial stress and performance feedback on pain processing and its correlation with subjective and neuroendocrine parameters.

Previous research on stress-induced pain modulation suggests that moderate psychological stress usually leads to hyperalgesia while more severe threat results in hypoalgesia. However, existing studies often lack suitable control conditions imperative to identify mere stress effects. Similarly, research mainly focused on pure of a social threat, not taking into consideration experiences of social evaluation. Therefore, we set out to investigate actual social up- and downgrading combined with a standardized stress paradigm to evaluate short-term and prolonged changes in pain perception and their potential association with neuroendocrine and subjective stress parameters.

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Two types of peptides derived from the neurotoxin GsMTx4 inhibit a mechanosensitive potassium channel by modifying the mechano-gate.

Atrial fibrillation (AF) is the most common sustained cardiac arrhythmia in humans. Current AF antiarrhythmic drugs have limited efficacy and carry the risk of ventricular pro-arrhythmia. GsMTx4, a mechanosensitive channel (MSC)-selective inhibitor, has been shown to suppress arrhythmias through the inhibition of stretch-activated channels (SACs) in the heart. The cost of synthesizing this peptide is a major obstacle to clinical use. Here, we studied two types of short peptides derived from GsMTx4 for their effects on a stretch-activated big potassium (BK) channel (SAKcaC) from the heart. Type I, a 17-residue peptide (referred to as Pept 01), showed comparable efficacy, whereas type II (i.e. Pept 02), a 10-residue peptide, exerted even more potent inhibitory efficacy on SAKcaC compared to GsMTx4. We identified through mutagenesis important sequences required for peptide functions. Additionally, molecular dynamics (MD) simulations revealed common structural features with a hydrophobic head followed by a positively charged protrusion that may be involved in peptide-channel/lipid interactions. Furthermore, we suggest that these short peptides may inhibit SAKcaC through a specific modification to the mechano-gate, as the inhibitory effects for both types of peptides were mostly abolished when tested with a mechano-insensitive channel variant (STREX-del) and a non-mechanosensitive BK (mSlo1) channel. These findings may offer an opportunity for the development of a new class of drugs in the treatment of cardiac arrhythmia generated by excitatory SACs in the heart..

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Synergistic antinociceptive effects of concomitant NAAA and peripheral FAAH inhibition.

The intracellular lipid amidases, fatty acid amide hydrolase (FAAH) and N-acylethanolamine acid amidase (NAAA), terminate the actions of anandamide and palmitoylethanolamide (PEA), two antinociceptive and anti-inflammatory lipid-derived mediators. Here we show, confirming prior research, that small-molecule inhibitors of peripheral FAAH (compound URB937) and systemic NAAA (compound ARN19702) individually attenuate, in male CD-1 mice, pain-related behaviors and paw inflammation in the formalin and carrageenan tests. More importantly, isobolographic analyses revealed that the combination of URB937 and ARN19702 produced substantial synergistic (greater than additive) antinociceptive effects in both models as well as additive anti-inflammatory effects in the carrageenan test. Together, the findings uncover a functional interplay between FAAH and NAAA substrates in the control of nociception, which might be exploited clinically to develop safe and effective pain management strategies.

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An International Multidisciplinary Delphi-Based Consensus on Heat Therapy in Musculoskeletal Pain.

Musculoskeletal pain (MP) is prevalent in our society, having a strong negative impact on physical and psychosocial quality of life. Heat therapy (HT) has been frequently described as a treatment strategy for musculoskeletal pain, but scientific evidence is still poor. The aim of the present Delphi method study is to gather a consensus among European experts on the role of HT in MP.

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Evaluation of the Anti-Inflammatory and Chondroprotective Effect of Celecoxib on Cartilage and in a Rat Osteoarthritis Model.

The potential chondroprotective effect of celecoxib, a nonsteroidal anti-inflammatory drug and selective cyclooxygenase-2 inhibitor used to reduce pain and inflammation in knee osteoarthritis patients, is disputed. This study aimed at investigating the chondroprotective effects of celecoxib on (1) human articular cartilage explants and (2) in an osteoarthritis rat model.

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Spinal Cord Stimulation Paradigms and Pain Relief: A Preclinical Systematic Review on Modulation of the Central Inflammatory Response in Neuropathic Pain.

Spinal cord stimulation (SCS) is a last-resort treatment for patients with chronic neuropathic pain. The mechanism underlying SCS and pain relief is not yet fully understood. Because the inflammatory balance between pro- and anti-inflammatory molecules in the spinal nociceptive network is pivotal in the development and maintenance of neuropathic pain, the working mechanism of SCS is suggested to be related to the modulation of this balance. The aim of this systematic review is to summarize and understand the effects of different SCS paradigms on the central inflammatory balance in the spinal cord.

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Evaluation of analgesic and anti-inflammatory activity of purine-2,6-dione-based TRPA1 antagonists with PDE4/7 inhibitory activity.

To verify the validity of the proposed pain treatment approach, which is based on concomitant blocking of the Transient Receptor Potential Ankyrin 1 (TRPA1) channel and phosphodiesterases (PDEs) 4B/7A activity, we continued our pharmacological studies on 8-alkoxypurine-2,6-diones selected based on previous in vitro screening.

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Effect of Galcanezumab on Total Pain Burden in Patients Who Had Previously Not Benefited from Migraine Preventive Medication (CONQUER Trial): A Post Hoc Analysis.

In evaluating therapies for migraine prevention, emphasis is placed on frequency and less attention is paid to duration or severity. Total pain burden (TPB) combines frequency, duration, and severity of migraine headache, and has the potential to further characterize the benefit of preventive treatment using a single composite measure. TPB was previously used to characterize response to galcanezumab (GMB) in patients with migraine. In this post hoc analysis we assessed the impact of GMB in lowering TPB in patients who had previously not benefited from two to four categories of migraine preventive medication.

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Identification and validation of MicroRNA-mRNA Networks in Dorsal Root Ganglia after Peripheral Nerve Injury.

Changes in DRG after nerve injury involve neuronal damage, apoptosis, pain transmission, and activation of regenerative programs. It is unclear which genes and microRNAs may play a major role in this process. Therefore, this study performed a meta-analysis of previously published gene expression data to reveal the potential microRNA-mRNA network in dorsal root ganglia (DRG) after peripheral nerve injury. We searched 5 mRNA and 3 microRNA expression data sets, obtained 447 differentially expressed genes (DEGs) and 5 differentially expressed miRNAs, determined the biological pathways enriched by these DEGs, and further predicted new microRNA-mRNA interactions, such as miR-21/Hmg20a, miR-221/Ube2ql1, miR-30c-1/Rhoq, miR-500/Sema3c, and miR-551b/Cdc42se2. We verified these hub mRNA and miRNA in rats by qRT-PCR and found the results were consistent with the bioinformatics analysis. And we predicted transcription factors associated with these genes (gTFs) and TFs associated with these microRNAs (mTFs) and constructed the mTF-miRNA-gene-gTF regulatory network to further explore the molecular mechanism in DRG. Finally, we compared the DRG transcriptome after PNI to that of chronic constriction injury (CCI), and found that PNI caused greater damage to DRG compared to CCI. At the same time, the related mechanisms of pain caused by the two pathophysiological process may be different.

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Investigation of Cav3.3 Dysfunction in Hemiplegic Migraine.

Familial hemiplegic migraine (FHM) is a severe neurogenetic disorder for which three causal genes, , , and , have been implicated. However, more than 80% of referred diagnostic cases of hemiplegic migraine (HM) are negative for exonic mutations in these known FHM genes, suggesting the involvement of other genes. Using whole-exome sequencing data from 187 mutation-negative HM cases, we identified rare variants in the gene encoding the T-type calcium channel Cav3.3. Burden testing of variants showed a statistically significant increase in allelic burden in the HM case group compared to gnomAD (OR = 2.30, = 0.00005) and the UK Biobank (OR = 2.32, = 0.0004) databases. Dysfunction in T-type calcium channels, including Cav3.3, has been implicated in a range of neurological conditions, suggesting a potential role in HM. Using patch-clamp electrophysiology, we compared the biophysical properties of five Cav3.3 variants (p.R111G, p.M128L, p.D302G, p.R307H, and p.Q1158H) to wild-type (WT) channels expressed in HEK293T cells. We observed numerous functional alterations across the channels with Cav3.3-Q1158H showing the greatest differences compared to WT channels, including reduced current density, right-shifted voltage dependence of activation and inactivation, and slower current kinetics. Interestingly, we also found significant differences in the conductance properties exhibited by the Cav3.3-R307H and -Q1158H variants compared to WT channels under conditions of acidosis and alkalosis. In light of these data, we suggest that rare variants in may contribute to HM etiology.

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A neuropathic component of tumor-related pain as a predictor of good response to palliative radiotherapy.

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Responding flexibly to the complex problem of chronic pelvic pain: Incorporating patient needs into program development.

Chronic pelvic pain (CPP) in women is both common and disabling, and access to interdisciplinary care is limited. Patient education programs may represent a pragmatic approach to delivering interdisciplinary care, but to date the specific educational needs of patients with CPP are unknown.

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Senolytic drugs relieve pain by reducing peripheral nociceptive signaling without modifying joint tissue damage in spontaneous osteoarthritis.

Aging is a risk factor for the development of osteoarthritis (OA), a progressive joint disease leading to cartilage damage, pain, and loss of function. In a mouse model of OA, senolytic drugs to selectively clear senescent cells (SnCs) that accumulate with injury or aging yielded a chondroprotective effect; however, this therapeutic benefit was limited in aged mice. Due to inconsistency between cartilage destruction and pain-associated symptoms, we studied the therapeutic effect of senolytics on joint pain in spontaneous OA. We orally treated 21- and 22-month old mice with an ABT263 and Dasatinib and Quercetin (D+Q) drug combination. Selective elimination of the SnCs that accumulated in the articular cartilage and synovium by these two drugs did not alter cartilage degeneration and abnormal bone changes during spontaneous OA progression. Treatment reduced thermal and mechanical hyperalgesia associated with OA and peripheral sensitization through decreased expression of axon guidance proteins (nerve growth factor NGF/TrkA) and nociceptive neuron (calcitonin gene-related peptide, CGRP) projection to the synovium, subchondral bone marrow, and dorsal root ganglion, and knee joint angiogenesis. Selective removal of the SnCs from cultures of synovial cells from human OA patients also decreased expression of senescent markers, axonal growth-promoting factors, such as NGF, and angiogenesis markers. We suggest that systemic administration of ABT263 and D+Q is an exciting therapeutic approach to age-related OA pain.

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Nerve Entrapment Syndrome: Chronic Lower Leg Pain in Athletes.

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Response to “Choroidal thickness in eyes of migraine patients measured using spectral domain-optical coherence tomography: A meta-analysis”.

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Sensory Changes Related to Dental Implant Placement: A Scoping Review.

To perform a scoping review of the literature to elucidate the occurrence of nerve damage related to dental implant placement and the factors causing the sensory changes.

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Difelikefalin: A New κ-Opioid Receptor Agonist for the Treatment of Hemodialysis-Dependent Chronic Kidney Disease-Associated Pruritus.

To review data for difelikefalin (Korsuva) intravenous solution for management of moderate-to-severe pruritus in hemodialysis (HD) patients.

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Avoid or seek light – a randomized crossover fMRI study investigating opposing treatment strategies for photophobia in migraine.

Photophobia, the aberrantly increased sensitivity to light, is a common symptom in migraine patients and light discomfort is frequently found as a trigger for migraine attacks. In behavioral studies, planned exposure to light was found to reduce headache in migraine patients with photophobia, potentially by increasing habituation to this migraine trigger. Here, we aimed to elucidate neurophysiological mechanisms of light exposure versus light deprivation in migraine patients using functional magnetic resonance imaging (fMRI).

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Prediction model for juvenile idiopathic arthritis: challenges and opportunities.

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Treating peripheral neuropathy in individuals with type 2 diabetes mellitus with intraneural facilitation: a single blind randomized control trial.

To evaluate the effectiveness of intraneural facilitation (INF) for the treatment of diabetic peripheral neuropathy (DPN).

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International Dermatology Outcome Measures (IDEOM): Report from the 2021 Annual Meeting.

International Dermatology Outcome Measures (IDEOM) is a non-profit organization founded in 2013. It is composed of researchers and stakeholders who work to develop evidenced-based outcome measures to enhance research and treatment recommendations of dermatologic diseases.

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Onset of Plaque Psoriasis Treatment Responses With Anti-IL-17/IL-23 Biologic Therapies.

The impact of psoriasis on quality of life arises from both physical symptoms, such as pain and pruritus, and the psychosocial effects of the often highly visible lesions. For patients with moderate-to-severe psoriasis seeking amelioration of these symptoms, time to onset of treatment response is an important consideration when determining an appropriate therapeutic approach with their healthcare provider.

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Specialized Microglia Resolve Neuropathic Pain in the Spinal Cord.

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Complementary/integrative healthcare utilization in US Gulf-War era veterans: Descriptive analyses based on deployment history, combat exposure, and Gulf War Illness.

Complementary and integrative health (CIH) approaches have gained empirical support and are increasingly being utilized among veterans to treat a myriad of conditions. A cluster of medically unexplained chronic symptoms including fatigue, headaches, joint pain, indigestion, insomnia, dizziness, respiratory disorders, and memory problems, often referred to as Gulf War Illness (GWI) prominently affect US Gulf War era (GWE) veterans, yet little is known about CIH use within this population. Using data collected as part of a larger study (n = 1153), we examined the influence of demographic characteristics, military experiences, and symptom severity on CIH utilization, and utilization differences between GWE veterans with and without GWI. Over half of the sample (58.5%) used at least one CIH modality in the past six months. Women veterans, white veterans, and veterans with higher levels of education were more likely to use CIH. GWE veterans with a GWI diagnosis and higher GWI symptom severity were more likely to use at least one CIH treatment in the past six months. Over three quarters (82.7%) of veterans who endorsed using CIH to treat GWI symptoms reported that it was helpful for their symptoms. Almost three quarters (71.5%) of veterans indicated that they would use at least one CIH approach if it was available at VA. Results provide a deeper understanding of the likelihood and characteristics of veterans utilizing CIH to treat health and GWI symptoms and may inform expansion of CIH modalities for GWE veterans, particularly those with GWI.

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The Role of Exercise in Treating Low Back Pain.

The purpose of this review is to highlight the role of exercise in preventing and managing acute and chronic axial low back pain (LBP). LBP is one of the leading contributors to years lived with disability as well as health care expenditures in the United States. With an expected increase in prevalence due to an aging population, sports medicine providers have a unique opportunity to provide effective treatment strategies incorporating exercise advice and prescription. Although the majority of individuals with acute LBP will have their symptoms resolve spontaneously, almost 40% will have recurrence or develop chronic LBP within 1 year. No single exercise method has been shown to be more effective than another. The evidence for walking programs, aerobic exercise, yoga, Pilates, and tai chi for LBP is discussed. Our review summarizes the beneficial role of a personalized exercise program and related counseling strategies in the prevention and management of LBP.

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In Schizophrenia, Chronic Fatigue Syndrome- and Fibromyalgia-Like Symptoms are Driven by Breakdown of the Paracellular Pathway with Increased Zonulin and Immune Activation-Associated Neurotoxicity.

A meaningful part of schizophrenia patients suffer from physiosomatic symptoms (formerly named psychosomatic) which are reminiscent of chronic fatigue syndrome and fibromyalgia (FF) and are associated with signs of immune activation and increased levels of tryptophan catabolites (TRYCATs).

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Feasibility of quantitative sensory testing in juvenile idiopathic arthritis.

Juvenile Idiopathic Arthritis (JIA) is a childhood-rheumatic disease with pain as a major early complaint, and in 10-17% pain remains a major symptom. Very few data exist on sensory threshold changes at the knee in JIA, a location in which inflammation often manifests. We determined whether JIA is associated with sensory threshold changes at the knee by using Quantitative Sensory Testing (QST) and established reference values at the knee of children.

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Opioid Initiation and the Hazard of Falls or Fractures Among Older Adults with Varying Levels of Central Nervous System Depressant Burden.

Co-prescription of opioids with other central nervous system (CNS) depressants is common but the combination may increase the risk for adverse events such as falls and fractures, particularly among older adults. We explored the risk of fall- or fracture-related hospital visits after opioid initiation among older adults with varying degrees of concomitant CNS depressant burden.

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Psychological Therapies and Mind-Body Techniques in the Management of Dermatologic Diseases: A Systematic Review.

There is a clear link between skin disease and psychological factors and this relationship works both ways: skin diseases can cause psychological distress and psychological issues can worsen skin disease. There are a number of therapies that approach this problem from the psychological side and may be useful, especially as adjunctive therapies in select patients.

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Foramen magnum decompression for Chiari malformation type I – UK surgical practice.

Symptomatic Chiari 1 malformation (CM1) is a common condition in Neurosurgery. Surgery involves hindbrain decompression and restoration of CSF flow through different surgical approaches. No Class 1 evidence exists to suggest the superiority of any of the surgical techniques. To investigate current surgical practice for symptomatic CM1 patients in the United Kingdom (UK) and determine the willingness to participate in a randomised controlled trial (RCT) comparing different surgical techniques. An electronic survey was sent to consultant members of the Society of British Neurological Surgeons and the British Chiari-Syringomyelia Group. The questions covered pre-operative and intra-operative management, presence of equipoise/uncertainty in optimal technique and willingness to participate in an RCT. 98 responses were received. 67% operate on adults. 30% on adult and paediatric patients. There is variation in routine pre-operative use of: ICP monitoring (18%), flexion/extension x-rays (16%), venography (20%) and ophthalmology assessment (26%). 18% of neurosurgeons would not offer foramen magnum decompression when the presenting symptom is only refractory cough/sneeze headache. 15% routinely perform bony decompression alone in adults vs 8% in children. In 68% of adult cases, durotomy is performed routinely (46% of them leave the dura open, 54% perform a type of duroplasty) and 16% routinely resect the cerebellar tonsils. Only 17% leave the dura open in children. The most common indicators for durotomy are syringomyelia and intra-operative ultrasound findings. 61% believe there is equipoise/uncertainty in the optimal strategy for decompression and would be willing to participate in an RCT. Comments also mention the heterogeneity of CM1 and that treatment should be tailored to each patient. There is wide variation in pre- and intra-operative management of CM1 patients in the UK and the majority of neurosurgeons would be willing to participate in an RCT comparing bony decompression alone vs dural opening with/without duroplasty.

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Orofacial Pain and Snoring/Obstructive Sleep Apnea in Individuals with Head and Neck Cancer: A Critical Review.

(1) To summarize current knowledge on the prevalence, intensity, and descriptors of orofacial pain and snoring/obstructive sleep apnea (OSA) before and after head and neck cancer (HNC) treatment; and (2) to propose future directions for research.

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Use of regional analgesia to prevent the conversion from acute to chronic pain.

Chronic post-surgical pain (CPSP) prevalence has not changed over the past decades what questions the efficacy of preventive strategies. Regional analgesia is used to control acute pain, but preventive effect on CPSP remains debated. Failures and future application of regional analgesia to prevent transition from acute to chronic pain will be discussed.

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Foot pain and inflammatory markers: a cross sectional study in older adults.

Foot disorders may limit independence and reduce quality of life for older adults. Obesity is a risk factor for foot conditions; both mechanical load and metabolic effects may contribute to these conditions. This study determined cross-sectional associations between inflammatory markers and foot disorders.

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Measuring interictal burden among people affected by migraine: a descriptive survey study.

Previous research has extensively documented the impact of migraine episodes ('ictal') on patients' health-related quality of life. Few studies have looked at the impact of migraine on migraine-free days ('interictal'). This study was designed to describe interictal burden of migraine in a mixed group of people affected by migraine and to explore patient characteristics associated with interictal burden.

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Atypical Migraine in Clinical Practice: Are We Missing It?

In countries like India, many migraine patients presenting to primary care clinics fail to fulfill standard (ICHD 3) migraine diagnostic criteria. Since they do not present with typical ICHD 3 migraine diagnostic symptoms, it is necessary to define the criteria for atypical migraine. This would ensure that the patients receive the right treatment approach, both non-pharmacological and pharmacological. Looking for triggers, family history, activity affected and absolute normality in between attacks, past episodes of episodic syndromes, prodromal and oculonasal autonomic symptoms will help in identifying the migraine origin of these headaches.

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Usability Study of the iACTwithPain Platform: An Online Acceptance and Commitment Therapy and Compassion-Based Intervention for Chronic Pain.

This pilot study aims to test the usability of the iACTwithPain platform, an online ACT-based intervention for people with chronic pain, to obtain information on which intervention and usability aspects need improvement and on expected retention rates.

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Neural changes after Emotional Freedom Techniques treatment for chronic pain sufferers.

This clinical trial investigated the effect of an Emotional Freedom Techniques (EFT) intervention on brain activation in chronic pain sufferers using functional magnetic resonance imaging (fMRI). EFT is a brief stress reduction technique which combines stating a cognitive statement with somatic tapping on acupressure points. Twenty-four adults were allocated to a six-week online group EFT treatment and underwent resting-state fMRI pre and post the intervention. A repeated measures MANOVA indicated significant differences in the levels of pain severity (-21%), pain interference (-26%), quality of life (+7%), somatic symptoms (-28%), depression (-13.5%), anxiety (-37.1%), happiness (+17%), and satisfaction with life (+8.8%) from pre-to post-test. Cohen's effect sizes ranged from small (0.2) to large (0.75) values suggesting significance for the intervention. fMRI analysis showed post-EFT treatment significantly decreased connectivity between the medial prefrontal cortex (a pain modulating area) and bilateral grey matter areas in the posterior cingulate cortex and thalamus, both areas being related to modulating and catastrophizing of pain. There were no brain areas that showed significantly increased connectivity post-EFT treatment. Coupled with the psychological measures the findings support the effects of the EFT intervention in reducing chronic pain and its impacts. Recommendations for future research are discussed.

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Sleep quality in individuals with chronic low back pain and central sensitization.

Sleep problems are common in individuals with chronic low back pain (CLBP). Central sensitization (CS) is present in a subgroup of individuals with CLBP. However, our knowledge about whether sleep quality varies between the subgroups of CLBP is limited. Therefore, we sought to examine whether the subgroup of CLBP with CS has poorer sleep quality than the subgroup without CS.

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Wnt3a/YTHDF1 Regulated Oxaliplatin-Induced Neuropathic Pain Via TNF-α/IL-18 Expression in the Spinal Cord.

Oxaliplatin is widely used in cancer treatment, however, many patients will suffer from neuropathic pain (NP) induced by it at the same time. Therefore exploring the mechanism and founding novel target for this problem are needed. In this study, YTHDF1 showed upregulation in oxaliplatin treated mice. As m6A is known as conserved and it widely functions in numerous physiological and pathological processes. Therefore, we focused on exploring the molecular mechanism of whether and how YTHDF1 functions in NP induced by oxaliplatin. IHC and western blotting were conducted to measure proteins. Intrathecal injection for corresponding siRNAs in C57/BL6 mice or spinal microinjection for virus in YTHDF1 mice were applied to specially knockdown the expression of molecular. Von Frey, acetone test and ethyl chloride (EC) test were applied to evaluate NP behavior. YTHDF1, Wnt3a, TNF-α and IL-18 were increased in oxaliplatin treated mice, restricted the molecular mentioned above respectively can significantly attenuate oxaliplatin-induced NP, including the mechanical allodynia and cold allodynia. Silencing YTHDF1 and inhibiting Wnt3a and Wnt signaling pathways can reduce the enhancement of TNF-α and IL-18, and the decreasing of the upregulation of YTHDF1 can be found when inhibiting Wnt3a and Wnts signaling pathways in oxaliplatin treated mice. Our study indicated a novel pathway that can contribute to oxaliplatin-induced NP, the Wnt3a/YTHDF1 to cytokine pathway, which upregulating YTHDF1 functioned as the downstream of Wnt3a signal and promoted the translation of TNF-α and IL-18 in oxaliplatin treated mice.

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Headache-related circuits and high frequencies evaluated by EEG, MRI, PET as potential biomarkers to differentiate chronic and episodic migraine: Evidence from a systematic review.

The diagnosis of migraine is mainly clinical and self-reported, which makes additional examinations unnecessary in most cases. Migraine can be subtyped into chronic (CM) and episodic (EM). Despite the very high prevalence of migraine, there are no evidence-based guidelines for differentiating between these subtypes other than the number of days of migraine headache per month. Thus, we consider it timely to perform a systematic review to search for physiological evidence from functional activity (as opposed to anatomical structure) for the differentiation between CM and EM, as well as potential functional biomarkers. For this purpose, Web of Science (WoS), Scopus, and PubMed databases were screened.

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The interplay between endometriosis and fertility in rats: a systematic review.

For the last decades, endometriosis has been a major gynecological problem and a significant cause of infertility for women worldwide. It is estimated that the disease affects about 10-15% of all women of reproductive age and 70% of women suffering from chronic pelvic pain. At the same time, the incidence is about 40-60% in women with dysmenorrhea and 20-30% in women with subfertility. Despite the high percentage of affected women, endometriosis is still characterized by insufficient knowledge of the pathogenic processes, leading to the development and continuity of the disease. For this reason, there is a significant need for insight and understanding of the pathogenesis of endometriosis. This systematic review aims to present the latest data on the use of rats in endometriosis research and to explore how fertility is affected in rats with endometriosis. The methodology included a review of the available publications retrieved by a search in various scientific databases, such as PubMed, Scopus, Medline, and Google Scholar. The initial search generated 30 titles, with 10 articles fulfilling the inclusion criteria. In conclusion, several surgical techniques have been proposed to induce endometriosis, mainly using rats as the appropriate animal model. Studies in rats showed that endometriosis causes infertility and that pregnancy rates are lower for rats with endometriosis than those without endometriosis. In addition, rats with endometriosis have significant abnormalities in the structure of their oocytes as well as in the development of their embryos (genetic abnormalities).

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Cancer Survivors’ Perspectives of Virtual Yoga for Chronic Chemotherapy-Induced Peripheral Neuropathy Pain During the COVID-19 Pandemic.

With the rise in telehealth due to the COVID-19 pandemic, further research is needed to determine how to optimize virtual delivery of existing integrative oncology interventions for cancer treatment-related symptoms. The purpose of this qualitative analysis was to explore cancer survivors' perspectives of the acceptability and satisfaction of an 8-week, virtual yoga intervention for cancer survivors with chronic chemotherapy-induced peripheral neuropathy pain. Fourteen participants with chronic chemotherapy-induced peripheral neuropathy pain who completed the virtual yoga intervention were interviewed using a semistructured interview guide. Themes were derived from the data using inductive content analysis methods. Main findings from the interviews included the following: (1) participants were willing to try new nonpharmacological treatments for chemotherapy-induced peripheral neuropathy due to the high symptom burden and prior lack of success with medications; (2) participants highly rated the flexibility offered by the virtual format, but desired the social support potentially offered by practicing in-person yoga; and (3) the impact of virtual yoga on chemotherapy-induced peripheral neuropathy severity was unclear. There were several barriers to participants' use of virtual yoga for chronic chemotherapy-induced peripheral neuropathy pain (eg, technology, lack of space/equipment). The results may be used to improve the design and delivery of future trials testing virtual yoga for chronic chemotherapy-induced peripheral neuropathy pain.

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Sexual functioning among adults with chronic pain: Prevalence and association with pain-related outcomes.

Prior research indicates that sexual functioning and chronic pain commonly co-exist and impact each other; however, there are limitations in current research as to the prevalence and severity of sexual dysfunction in patients with chronic pain.

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