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Neuralgic amyotrophy is a common peripheral nerve disorder caused by autoimmune inflammation of the brachial plexus, clinically characterized by acute pain and weakness of the shoulder muscles, followed by motor impairment. Despite recovery of the peripheral nerves, patients often have residual motor dysfunction of the upper extremity, leading to persistent pain related to altered biomechanics of the shoulder region. Building on clinical signs that suggest a role for cerebral mechanisms in these residual complaints, here we show and characterize cerebral alterations following neuralgic amyotrophy. Neuralgic amyotrophy patients often develop alternative motor strategies, which suggests that (mal)adaptations may occur in somatomotor and/or visuomotor brain areas. Here, we tested where changes in cerebral sensorimotor representations occur in neuralgic amyotrophy, while controlling for altered motor execution due to peripheral neuropathy. We additionally explore the relation between potential cerebral alterations in neuralgic amyotrophy and clinical symptoms. During functional MRI scanning, 39 neuralgic amyotrophy patients with persistent, lateralized symptoms in the right upper extremity and 23 matched healthy participants solved a hand laterality judgement task that can activate sensorimotor representations of the upper extremity, across somatomotor and visuomotor brain areas. Behavioural and cerebral responses confirmed the involvement of embodied, sensorimotor processes across groups. Compared with healthy participants, neuralgic amyotrophy patients were slower in hand laterality judgement and had decreased cerebral activity specific to their affected limb in two higher-order visual brain regions: the right extrastriate cortex and the parieto-occipital sulcus. Exploratory analyses revealed that across patients, extrastriate activity specific to the affected limb decreased as persistent pain increased, and affected limb-related parieto-occipital activity decreased as imagery performance of the affected limb became slower. These findings suggest that maladaptive cerebral plasticity in visuomotor areas involved in sensorimotor integration plays a role in residual motor dysfunction and subsequent persistent pain in neuralgic amyotrophy. Rehabilitation interventions that apply visuomotor strategies to improve sensorimotor integration may help to treat neuralgic amyotrophy patients.
Learn More >Pain-related sensory input is processed in the spinal dorsal horn (SDH) before being relayed to the brain. That processing profoundly influences whether stimuli are correctly or incorrectly perceived as painful. Significant advances have been made in identifying the types of excitatory and inhibitory neurons that comprise the SDH, and there is some information about how neuron types are connected, but it remains unclear how the overall circuit processes sensory input or how that processing is disrupted under chronic pain conditions. To explore SDH function, we developed a computational model of the circuit that is tightly constrained by experimental data. Our model comprises conductance-based neuron models that reproduce the characteristic firing patterns of spinal neurons. Excitatory and inhibitory neuron populations, defined by their expression of genetic markers, spiking pattern, or morphology, were synaptically connected according to available qualitative data. Using a genetic algorithm, synaptic weights were tuned to reproduce projection neuron firing rates (model output) based on primary afferent firing rates (model input) across a range of mechanical stimulus intensities. Disparate synaptic weight combinations could produce equivalent circuit function, revealing degeneracy that may underlie heterogeneous responses of different circuits to perturbations or pathological insults. To validate our model, we verified that it responded to reduction of inhibition (i.e. disinhibition) and ablation of specific neuron types in a manner consistent with experiments. Thus validated, our model offers a valuable resource for interpreting experimental results and testing hypotheses to plan experiments for examining normal and pathological SDH circuit function.We developed a multiscale computer model of the posterior part of spinal cord gray matter (spinal dorsal horn), involved in perception of touch and pain. The model reproduces several experimental observations and makes predictions about how specific types of spinal neurons and synapses influence projection neurons that send information to the brain. Misfiring of these projection neurons can produce anomalous sensations associated with chronic pain. Our computer model will not only assist in planning future experiments, but will also be useful for developing new pharmacotherapy for chronic pain disorders, connecting the effect of drugs acting at the molecular scale with emergent properties of neurons and circuits that shape the pain experience.
Learn More >The current paradigm is that inflammatory pain passively resolves following the cessation of inflammation. Yet, in a substantial proportion of patients with inflammatory diseases, resolution of inflammation is not sufficient to resolve pain, resulting in chronic pain. Mechanistic insight into how inflammatory pain is resolved is lacking. Here, we show that macrophages actively control resolution of inflammatory pain remotely from the site of inflammation by transferring mitochondria to sensory neurons. During resolution of inflammatory pain in mice, M2-like macrophages infiltrate the dorsal root ganglia that contain the somata of sensory neurons, concurrent with the recovery of oxidative phosphorylation in sensory neurons. The resolution of pain and the transfer of mitochondria requires expression of CD200 receptor (CD200R) on macrophages and the non-canonical CD200R-ligand iSec1 on sensory neurons. Our data reveal a novel mechanism for active resolution of inflammatory pain.
Learn More >A pharmacological approach to pain control after cesarean delivery is often insufficient on its own. Acupuncture is a promising method for mitigating postoperative pain and reducing postoperative opioid requirements.
Learn More >The sensations of touch and pain are fundamental components of our daily life, which can transport vital information about the surroundings and provide protection to our bodies. In this study, the transmission process of sensing pressure stimuli to dorsal root neurons (nociceptors) was simulated using electronic devices. In this regard, we proposed and experimentally demonstrated a biomimetic nociceptor system with tactile perception. In this system, the sensing paper as E-skin simulates the biological skin to sense external pressure stimulation and generate electrical signals, while the threshold switching memristor simulates the biological nociceptor to receive and process the receptor signals. The W/VO/Pt memristor exhibits all key features of nociceptors including threshold, relaxation, "no adaptation" and sensitization phenomena of allodynia and hyperalgesia. The E-skin shows high sensitivity and a broad sensing range and is capable of monitoring different human movements and physiological signals. With the bio-inspired artificial tactile nociceptive system, the threshold and sensitization properties under pressure stimuli are obtained successfully. Notably, this system could be used as an artificial tactile alarm system to demonstrate the potential applicability of humanoid robots. Thus, the present work is of great significance to the development of hardware architecture in artificial intelligence systems and replacement neuroprosthetics.
Learn More >As a predominately positive emotion, nostalgia serves various adaptive functions, including a recently revealed analgesic effect. The current fMRI study aimed to explore the neural mechanisms underlying the nostalgia-induced analgesic effect on noxious thermal stimuli of different intensities. Human participants' (males and females) behavior results showed that the nostalgia paradigm significantly reduced participants' perception of pain, particularly at low pain intensities. fMRI analysis revealed that analgesia was related to decreased brain activity in pain-related brain regions, including the lingual and parahippocampal gyrus. Notably, anterior thalamic activation during the nostalgia stage predicted posterior parietal thalamus activation during the pain stage, suggesting that the thalamus might play a key role as a central functional linkage in the analgesic effect. Moreover, while thalamus-PAG functional connectivity was found to be related to nostalgic strength, PAG-dlPFC functional connectivity was found to be associated with pain perception, suggesting possible analgesic modulatory pathways. These findings demonstrate the analgesic effect of nostalgia and, more importantly, shed light on its neural mechanism.Nostalgia is known to reduce individuals' perception of physical pain. The underlying brain mechanisms, however, are unclear. Our study found that the thalamus plays a key role as a functional linkage between nostalgia and pain, suggesting a possible analgesic modulatory mechanism of nostalgia. These findings have implications for the underlying brain mechanisms of psychological analgesia.
Learn More >The common technique using a basal infusion for an ambulatory continuous peripheral nerve blocks frequently results in exhaustion of the local anesthetic reservoir prior to resolution of surgical pain. We sought to improve and prolong analgesia by delaying initiation using an integrated timer and delivering a lower hourly volume of local anesthetic as automated boluses. We hypothesized that, compared with a traditional continuous infusion, ropivacaine administered with automated boluses at a lower dose and 5-hour delay would (1) provide at least noninferior analgesia [difference in average pain no greater than 1.7 points] while both techniques were functioning [average pain score day after surgery]; and, (2) result in a longer duration [dual primary outcomes].
Learn More >Excessive intravascular release of lysed cellular contents from damaged red blood cells (RBCs) in patients with sickle cell anemia (SCA) can activate the inflammasome, a multiprotein oligomer promoting maturation and secretion of pro-inflammatory cytokines, including interleukin 1-beta (IL-1b). We hypothesized that IL-1b blockade by canakinumab in patients with SCA would reduce markers of inflammation and clinical disease activity. In this randomized, double-blind, multi-center phase 2a study, patients aged 8-20 years old with SCA (HbSS or HbSb0thalassemia), history of acute pain episodes and elevated hsCRP >1.0 mg/L at screening were randomized 1:1 to received 6 monthly treatments with 300 mg s.c. canakinumab or placebo. Measured outcomes at baseline and weeks 4, 8, 12, 16, 20 and 24 included electronic patient-reported outcomes, hospitalization rate and adverse events (AEs) and serious AEs (SAEs). All but one of the 49 enrolled patients were receiving stable background hydroxyurea therapy. Although the primary objective (pre-specified reduction of pain) was not met, compared to placebo-arm patients, canakinumab-treated patients had reductions in markers of inflammation, occurrence of SCA-related AE and SAE, and number and duration of hospitalizations, as well as trends for improvement in pain intensity, fatigue and absences from school or work. Post-hoc analysis revealed treatment effects on weight, restricted to pediatric patients. Canakinumab was well tolerated with no treatment-related SAEs and no new safety signal. These findings demonstrate that the inflammation associated with SCA can be reduced by selective IL-1b blockade by canakinumab with potential for therapeutic benefits. This trial was registered at www.clinicaltrials.gov as NCT02961218.
Learn More >The switching variability caused by intrinsic stochasticity of the ionic/atomic motions during the conductive filaments (CFs) formation process largely limits the applications of diffusive memristors (DMs), including artificial neurons, neuromorphic computing and artificial sensory systems. In this study, a DM device with improved device uniformity based on well-crystallized two-dimensional (2D) h-BN, which can restrict the CFs formation from three to two dimensions due to the high migration barrier of Ag between h-BN interlayer, is developed. The BN-DM has potential arrayable feature with high device yield of 88%, which can be applied for building a reservoir computing system for digital pattern recognition with high accuracy rate of 96%, and used as an artificial nociceptor to sense the external noxious stimuli and mimic the important biological nociceptor properties. By connecting the BN-DM to a self-made triboelectric nanogenerator (TENG), a self-power mechano-nociceptor system, which can successfully mimic the important nociceptor features of "threshold", "relaxation" and "allodynia" is designed.
Learn More >Methyltransferase-like 3 (METTL3)-modulated N6-methyladenosine (m6A) was recently identified as an important epigenetic regulation type during RNA processing and contributes to multiple pathological processes. Neuropathic pain (NP) is induced by a lesion of the somatosensory nervous system, and the detailed pathways by which METTL3/m6A regulated to modulate gene dysregulation and enable NP have remained unclear. Therefore, this study investigated the function of METTL3-mediated m6A methylation on miRNA maturation, and investigated how this regulation contributes to NP progression. A rat model characterized with typical NP was established by a spared nerve-injury (SNI) method. By analyzing the expression levels of METTL3 and m6A methylation, we found that METTL3, along with m6A methylation, was dramatically downregulated in NP rats in contrast to the sham ones. Functionally, enhanced METTL3 promoted the m6A methylation in total RNAs and inhibited NP progression, whereas silencing METTL3 suppressed m6A methylation and increased NP severity. Mechanistically, METTL3 accelerated miR-150 maturation via mediating m6A methylation of primiR-150 at locus 498, cooperating with the "m6A reader" YTHDF2. Meanwhile, miR-150 could directly target brain-derived neurotrophic factor (BDNF) mRNA, and the METTL3/miR-150/BDNF regulatory pathway was finally established. Clinically, we proved that serum METTL3 mRNA was also downregulated in Shingles patients with NP, suggesting its diagnostic potential. In conclusion, we demonstrated an essential function of METTL3-regulated N6-methyladenosine during NP progression via modulating primiR-150 maturation. Serum METTL3 could effectively differentiate NP patients from healthy people, and is useful for dynamic monitoring of diseases after treatment. Therefore, the METTL3/miR-150/BDNF pathway may be a promising therapeutic target for NP patients.
Learn More >Suicidality is a common public health concern in young people. Previous research has highlighted pain as a key correlate of suicidality in young people. However, the long-term experience of pain may vary between individuals, and the relationship between distinct pain trajectories and suicidality is poorly understood. This study aims to describe the number and nature of distinct pain trajectories, their demographic and clinical correlates, including baseline suicidality, and whether identified pain trajectories may predict future suicidality. Secondary data analyses were performed, using longitudinal data from the British Child and Adolescent Mental Health Survey (N = 7977), collected at five timepoints between 2004 and 2007 on a population-based sample of UK youth (5-16 years). Data were collected from up to three respondents (parents, teachers, and 11 + year-olds). Latent Class Growth Analysis was used to identify distinct pain trajectories, explore predictors of these trajectories, and establish whether trajectories predicted future suicidality. We identified the following four pain trajectories: increasing (33.6%), decreasing (4.5%), persistent/recurrent probability of pain (15.7%), and no pain (46.2%). Pain trajectories were associated with unique demographic and clinical correlates. Only the persistent/recurrent (vs. no-pain) trajectory was predicted by baseline suicidality (aOR = 2.24; 95% bootstrap-CI = 1.59-3.26). Furthermore, the persistent/recurrent trajectory predicted future suicidality (aOR = 1.03, 95% bootstrap-CI = 1.01-1.06), after controlling for baseline suicidality, psychiatric disorder, age, and gender. Findings provide a better understanding of correlates associated with distinct pain trajectories and long-term risk of suicidality in young people, suggesting a bidirectional pain-suicidality association and emphasising the need of targeted support for young people with persistent/recurrent pain.
Learn More >The experience of chronic pain is influenced by gender, race, and age but is understudied in older Black women. Society and family alike expect Black older women to display superhuman strength and unwavering resilience. This qualitative study examined the narratives of 9 rural- and urban-dwelling Black older women to identify the ways in which they displayed strength while living with chronic osteoarthritis pain. Their "herstories" parallel the 5 characteristics of the Superwoman Schema/Strong Black Woman. Two additional characterizations emerged: spiritual submission for strength and code switching to suffering Black woman; these may be unique to Black Americans with pain.
Learn More >Patients undergoing elective orthopaedic surgery may experience pain that is acute, chronic or a combination of the two, with less than half of all surgical patients reporting adequate pain relief. The National Association of Orthopaedic Nurses (NAON) and the American Society for Pain Management Nursing (ASPMN) have partnered to provide evidence-informed guidance to empower nurses to employ effective pain management. Understanding and applying ethical, evidence-informed, patient-focused, interprofessional interventions will improve outcomes for patients, clinicians, and healthcare organizations. Together, we encourage nurses to embrace the guiding principles presented in this Position Statement to provide optimal pain management for the orthopaedic patient.
Learn More >Neuropathic pain produced by symptomatic neuromas is an important problem after peripheral nerve injury (PNI). End-to-end anastomosis of the nerve stump for PNI is well established but cannot efficiently prevent neuroma-in-continuity formation.
Learn More >Gabapentinoids are increasingly prescribed to manage chronic noncancer pain (CNCP) in older adults. When used concurrently with opioids, gabapentinoids may potentiate central nervous system (CNS) depression and increase the risks for fall. We aimed to investigate whether concurrent use of gabapentinoids with opioids compared with use of opioids alone is associated with an increased risk of fall-related injury among older adults with CNCP.
Learn More >The Neck Disability Index (NDI) is a self-rated disability tool originally developed for whiplash associated disorders and validated in cervical musculoskeletal conditions. It is now commonly used to assess neck disability in migraine but it is unknown whether NDI scores relate to migraine and hypersensitivity, cervical musculoskeletal dysfunction or both. This single-blinded observational study aimed to determine whether the presence of cervical musculoskeletal dysfunction, migraine features and hypersensitivity predict NDI scores and whether alternate versions of the NDI (NDI-physical, NDI-8, NDI-5) relate more to cervical musculoskeletal dysfunction.
Learn More >Evidence supports that tension-type headache (TTH) involves complex underlying mechanisms. The current study aimed to quantify potential multivariate relationships between headache-related, psychophysical, psychological and health-related variables in patients with TTH using network analysis.
Learn More >Chronic pain conditions are common and have a considerable impact on health and wellbeing. This impact can be reduced by cognitive behavioral therapy (CBT), the most commonly applied psychological approach to chronic pain. At the same time, CBT continues to develop, and now includes what is sometimes called "third wave" CBT. In this review, we examine the evidence for application of acceptance and commitment therapy (ACT), a principal example of this new wave or latest generation of treatment approaches, in people with chronic pain. We identified 25 randomized controlled trials of ACT for adults with chronic pain. Across the included trials, small to large effect sizes favoring ACT were reported for key outcomes including pain interference, disability, depression, and quality of life. Evidence from three studies provided some support for the cost effectiveness of ACT for chronic pain. Evidence also supported the mediating role of theoretically consistent processes of change (psychological flexibility) in relation to treatment outcomes. Investigation of moderators and predictors of outcomes was limited and inconsistent. In future, a greater focus on process based treatments is recommended. This should include continued identification of evidence based processes of change, and research methods more suited to understanding the experience and needs of individual people.
Learn More >The purpose of this study was to investigate the mechanism of antiallodynic effect of tizanidine in neuropathic rats. Spinal nerve ligation reduced withdrawal threshold which was interpreted as tactile allodynia. Increasing doses of tizanidine induced a dose-dependent antiallodynic effect in nerve injured rats. Tizanidine was more effective in female than male neuropathic rats. This drug induced a lower antiallodynic effect in ovariectomized, compared with non-ovariectomized, neuropathic rats, while systemic reconstitution of estradiol (E2) levels in ovariectomized neuropathic females fully restored the antiallodynic effect of tizanidine. Naloxone reduced the antiallodynic effect of tizanidine in male but not in female neuropathic rats. Ovariectomy restored the antagonizing effect of naloxone in the antiallodynic effect of tizanidine, whereas treatment with E2 abolished the effect of naloxone on tizanidine activity. Rauwolscine (α antagonist) and imiloxan (α antagonist) completely abated tizanidine-induced antiallodynic effect in female neuropathic rats. In contrast, BRL-44408 (α antagonist) partially decreased the effect of tizanidine while JP-1302 (α antagonist) was ineffective. Rauwolscine, imiloxan and BRL-44408 decreased withdrawal threshold in naïve female rats. Rauwolscine did not modify withdrawal threshold in naïve male rats. AGN192403 (I antagonist), BU224 (I antagonist), prazosin (α antagonist) and methiothepin (5-HT antagonist) did not modify tizanidine-induced antiallodynia in neuropathic females and males. These data indicate that tizanidine exhibits a sex-dependent antiallodynic effect in neuropathy. Data also suggest that activation of adrenergic α and α and opioid receptors participate in the antiallodynic effect of tizanidine in female and male, respectively, neuropathic rats.
Learn More >Fibromyalgia is a chronic painful condition without real, effective treatment. The administration of repetitive transcranial magnetic stimulation (rTMS) has been shown to have a therapeutic effect on pain, but there are still questions about the maintenance of its effect over time. Continuation of the treatment upon clinical response through maintenance sessions is promising and merits further exploration.
Learn More >Spontaneous intracranial hypotension is caused by loss of CSF at the level of the spine. The most frequent symptom of this disorder is orthostatic headache, with the headache worsening in the upright position and subsiding after lying down. Neuroimaging has a crucial role in diagnosing and monitoring spontaneous intracranial hypotension, because it provides objective (albeit often subtle) data despite the variable clinical syndromes and often normal lumbar puncture opening pressure associated with this disorder. Spine imaging aims to classify and localise the site of CSF leakage as either (1) a ventral dural leak, (2) a leaking spinal nerve root diverticulum, or (3) a direct CSF-venous fistula. Searching for a CSF leak can be very difficult; the entire spine must be scrutinised for a dural breach often the size of a pin. Precisely locating the site of CSF leakage is fundamental to successful treatment, which includes a targeted epidural patch and surgical closure when conservative measures do not provide long-term relief. Increased awareness of spontaneous intracranial hypotension among clinicians highlights the need for dedicated diagnostic and therapeutic guidelines.
Learn More >Inhibiting receptor tyrosine kinases is commonly achieved by two main strategies targeting either the intracellular kinase domain by low molecular weight compounds or the extracellular ligand-binding domain by monoclonal antibodies. Identifying small molecules able to inhibit RTKs at the extracellular level would be highly desirable to gain exquisite selectivity but is believed to be challenging owing to the size of RTK endogenous ligands (cytokines, growth factors) and the topology of RTK extracellular domains. We here report the high-throughput screening of the French Chemical Library (48K compounds) for extracellular inhibitors of the Fms-like tyrosine kinase 3 (FLT3) receptor tyrosine kinase, by a homogeneous time-resolved fluorescence competition assay. A total of 679 small molecular weight ligands (1.4%) were confirmed to strongly inhibit (>75%) the binding of the fluorescent labeled FLT3 ligand (FL cytokine) to FLT3 overexpressed in HEK-293 cells, at two different concentrations (5 and 20 μM). Concentration-response curves, obtained for 111 lead-like molecules, confirmed the unexpected tolerance of the FLT3 extracellular domain for low molecular weight druggable inhibitors exhibiting submicromolar potencies, chemical diversity, and promising pharmacokinetic properties. Further investigation of one hit confirmed inhibitory properties in dorsal root ganglia neurons and in a mouse model of neuropathic pain.
Learn More >Successful treatment of opioid misuse among people with chronic pain has proven elusive. Guidelines recommend nonopioid therapies, but the efficacy of mindfulness-based interventions for opioid misuse is uncertain.
Learn More >The roles and connectivity of specific types of neurons within the spinal cord dorsal horn (DH) are being delineated at a rapid rate to provide an increasingly detailed view of the circuits underpinning spinal pain processing. However, the effects of these connections for broader network activity in the DH remain less well understood because most studies focus on the activity of single neurons and small microcircuits. Alternatively, the use of microelectrode arrays (MEAs), which can monitor electrical activity across many cells, provides high spatial and temporal resolution of neural activity. Here, the use of MEAs with mouse spinal cord slices to study DH activity induced by chemically stimulating DH circuits with 4-aminopyridine (4-AP) is described. The resulting rhythmic activity is restricted to the superficial DH, stable over time, blocked by tetrodotoxin, and can be investigated in different slice orientations. Together, this preparation provides a platform to investigate DH circuit activity in tissue from naïve animals, animal models of chronic pain, and mice with genetically altered nociceptive function. Furthermore, MEA recordings in 4-AP-stimulated spinal cord slices can be used as a rapid screening tool to assess the capacity of novel antinociceptive compounds to disrupt activity in the spinal cord DH.
Learn More >Peripheral neuropathy is a common and progressive disorder in the elderly that interferes with daily activities. It is of importance to find efficient treatments to treat or delay this age-related neurodegeneration. Silencing macrophages by reducing foamy macrophages showed significant improvement of age-related degenerative changes in peripheral nerves of aged mice. We previously demonstrated that activation of the cholesterol sensor Liver X receptor (LXR) with the potent agonist, GW3965, alleviates pain in a diet-induced obesity model. We sought to test whether LXR activation may improve neuropathy in aged mice.
Learn More >Chronic pain is frequently reported after total hip and knee arthroplasties (THA/TKA) in osteoarthritis (OA) patients. We investigated if severity of acute postoperative pain following THA/TKA in OA patients was associated with pain during the first postoperative year. From an observational study, OA patients scheduled for primary THA/TKA (June 2012-December 2017) were included from two hospitals in the Netherlands. Acute postoperative pain scores were collected within 72 h postoperatively and categorized as no/mild (NRS ≤ 4) or moderate/severe (NRS > 4). Pain was assessed preoperatively, 3, 6 and 12 months postoperatively using the HOOS/KOOS subscale pain. With Multilevel Mixed-effects-analyses, we estimated associations between acute and chronic pain until one year postoperative, adjusted for confounders and including an interaction term (Time*Acute pain). 193 THA and 196 TKA patients were included, 29% of THA and 51% of TKA patients reported moderate/severe pain acutely after surgery. In the THA group, the difference in pain at 3 months between the no/mild and moderate/severe groups, was approximately six points, in favor of the no/mild group (95% CI [-12.4 to 0.9]) this difference became smaller over time. In the TKA group we found similar differences, with approximately four points (95% CI [-9.6 to 1.3]) difference between the no/mild and moderate/severe group at 6 months, this difference attenuated at 12 months. No association between severity of acute postoperative pain and pain during the first postoperative year was found. These findings suggest that measures to limit acute postoperative pain will likely not impact development of chronic pain.
Learn More >Endometriosis is a chronic gynecological disorder involved in the pathogenesis of chronic pelvic pain, based on a probable up regulation of the inflammatory system. The objective of the study is to investigate the peritoneal and serum levels of ENA-78 with the severity of endometriosis symptoms (dysmenorrhea, chronic pelvic pain and dyspareunia) using the visual analogue scale (VAS). This is a prospective case-control study that included 53 symptomatic women with evidence of endometriosis and 53 age-matched controls who underwent elective laparoscopic surgery for benign diseases. The concentration of ENA-78 was assessed in blood and peritoneal fluid samples in the follicular phase. In peritoneal fluid and plasma, the concentration of ENA-78 was significantly higher in cases than in controls (p < 0.001). A significant correlation was observed between peritoneal fluid ENA-78 levels and the severity of dysmenorrhea (Spearman Rho = 0.237; p = 0.014), and chronic pelvic pain (Spearman Rho = 0.220; p = 0.022) in endometriosis patients. Plasma levels ENA-78 showed a significant correlation with the severity (VAS score) of chronic pelvic pain (Spearman Rho = 0.270, p = 0.005 for cases), though a weak correlation was evident between plasma levels of ENA-78 and severity of dysmenorrhea (Spearman Rho = 0.083, p = 0.399 for cases). In conclusion, chronic pelvic pain in endometriosis is caused by changes of local and systemic activated chemokine patterns. These modifications involve the relationship between pro-inflammatory, angiogenic and angiostatic chemokines that modulate the severity of endometriosis associated symptoms.
Learn More >Several factors such as neck pain intensity, disability, anxiety, depression, female sex or a previous history of headache, are associated with post-whiplash headache. However, the possible role of psychosocial factors contributing to the presence of headache or worsening of headache after a whiplash trauma remains unclear. To address this gap in knowledge, there is the need to assess psychosocial factors concerning headache shortly after a whiplash injury.
Learn More >Both chronic pain and sleep disorders are associated with a reduction in the quality of life. They can be both a cause and a consequence of each other, and should therefore be simultaneously treated. However, optimal treatments for chronic pain-related sleep disorders are not well established. Here, we aimed to investigate the effects of suvorexant, a novel sleep drug, and mirtazapine, a noradrenergic and specific serotonergic antidepressant, on pain-related changes in sleep parameters in a preclinical chronic pain mice model, by partial sciatic nerve ligation. We evaluated the quantity, duration, and depth of sleep by analyzing the electroencephalogram and voluntary activity by counting the number of wheel rotations to determine various symptoms of sleep disorders, including reduced total sleep time, fragmentation, low quality, and impaired activity in the daytime. Suvorexant and mirtazapine normalized the reduction in sleep time and fragmented sleep, further regaining the sleep depth at sleep onset in the chronic pain state in nerve-ligated mice. Mirtazapine also increased the percentage of rapid eye movement sleep in mice. Suvorexant decreased voluntary activity, which was prolonged after administration; however, mirtazapine did not decrease it. Although the effects of suvorexant and mirtazapine on sleep and activity are different, both suvorexant and mirtazapine could be potential therapeutic agents for chronic pain-related sleep disorders.
Learn More >The purpose was to determine the efficacy of deep dry needling (DDN) applied on an active myofascial trigger point (MTrP) versus a latent-MTrP versus a non-MTrP location, on pain reduction and cervical disability, in patients with chronic neck pain. A randomized, double-blind clinical trial design was used. A sample of 65 patients was divided into non-MTrP-DDN, active-MTrP-DDN and latent-MTrP-DDN groups. The visual analog scale (VAS), reproduction of the patient's pain, number of local twitch responses, pressure pain threshold (PPT) and Neck Disability Index (NDI) were assessed before, during and after the intervention and up to 1 month post-intervention. The active-MTrP-DDN-group reduced pain intensity more than non-MTrP-DDN-group after a week and a month (P < 0.01), as well as showing the greatest improvement in tibialis muscle PPT. The treatment of both Active and Latent MTrPs was associated with the reproduction of the patient's pain. The application of DDN on an active-MTrP in the upper trapezius muscle shows greater improvements in pain intensity after 1 week and 1 month post-intervention, compared to DDN applied in latent-MTrPs or outside of MTrPs in patients with neck pain.
Learn More >Prokineticin 2 (PROK2) is a secreted bioactive peptide that regulates a variety of biological responses via two GPCRs, the prokineticin receptors (PROKRs). The aim of this study was to characterize a new alternatively spliced product of the gene consisting of four exons. The 40-amino acid peptide, designated PROK2C, is encoded by exon 1 and exon 4, and its expression was detected in the hippocampus and spinal cord of mice. PROK2C was expressed in a heterologous system, , and its binding specificity to the amino-terminal regions of PROKR1 and PROKR2 was investigated by GST pull-down experiments. In addition, the introduction of the unnatural amino acid p-benzoyl-L-phenylalanine using amber codon suppression technology demonstrated the role of tryptophan at position 212 of PROKR2 for PROK2C binding by photoactivatable cross-linking. The functional significance of this new isoform was determined in vivo by nociceptive experiments, which showed that PROK2C elicits strong sensitization of peripheral nociceptors to painful stimuli. In order to analyze the induction of PROK2C signal transduction, STAT3 and ERK phosphorylation levels were determined in mammalian CHO cells expressing PROKR1 and PROKR2. Our data show by in vivo and in vitro experiments that PROK2C can bind and activate both prokineticin receptors.
Learn More >Neuropathic pain (NP) is an abnormality resulting from lesion or damage to parts of the somatosensory nervous system. It is linked to defective quality of life and often poorly managed. Due to the limited number of approved drugs, limited efficacy and side effects associated with the approved drugs, drugs or drug combinations with great efficacy and very minimal or no side effects will be of great advantage in managing NP. This study aimed at investigating the synergistic antinociceptive effects of the combination of glucosamine sulphate (GS) (240 mg/kg) and chondroitin sulphate (CS) (900 mg/kg) in chronic constriction injury (CCI)-induced neuropathy in rats. Forty-two Wistar rats were randomly distributed into seven groups (n = 6). Sciatic nerve was ligated with four loose ligatures to induce NP. Effects of drugs were examined on stimulus and non-stimulus evoked potentials, expression of dorsal root ganglia (DRG) pain modulators and structural architecture of DRG. Oral administration of GS and CS for 21 days reduced hyperalgesia, allodynia, sciatic nerve functional aberration and DRG pain modulators. Histopathology and immunohistochemistry revealed restoration of structural integrity of DRG. Our result showed that the combination of GS and CS produced antinociceptive effects by attenuating hyperalgesia, allodynia and downregulation of NP mediators. GS and CS additionally produced synergistic analgesic effect over its individual components.
Learn More >Endometriosis is a common chronic gynaecological disease causing various symptoms, such as infertility and chronic pain. The gold standard for its diagnosis is still laparoscopy and the biopsy of endometriotic lesions. Here, we aimed to compare the eutopic endometrium from women with or without endometriosis to identify proteins that may be considered as potential biomarker candidates. Eutopic endometrium was collected from patients with endometriosis (n = 4) and women without endometriosis (n = 5) during a laparoscopy surgery during the mid-secretory phase of their menstrual cycle. Total proteins from tissues were extracted and digested before LC-MS-MS analysis. Among the 5301 proteins identified, 543 were differentially expressed and enriched in two specific KEGG pathways: focal adhesion and PI3K/AKT signaling. Integration of our data with a large-scale proteomics dataset allowed us to highlight 11 proteins that share the same trend of dysregulation in eutopic endometrium, regardless of the phase of the menstrual cycle. Our results constitute the first step towards the identification of potential promising endometrial diagnostic biomarkers. They provide new insights into the mechanisms underlying endometriosis and its etiology. Our results await further confirmation on a larger sample cohort.
Learn More >The goal of our study was to evaluate the burden of endometriosis in the community by comparing healthcare resource utilization, total direct medical costs, infertility, and comorbidity rates of women with and without a diagnosis of endometriosis. A retrospective case-control study was performed using the databases of a 2.1 million-member nationwide healthcare plan. The study population included women aged 15-55 years enrolled in the healthcare plan. Women with a diagnosis (ICD-9) of endometriosis were compared to controls without diagnosed endometriosis. Women were individually matched (1:4) on age and residence area. Patient characteristics were described, including infertility, comorbidities, and annual healthcare resource utilization. Total direct medical costs were analyzed in a generalized linear model adjusting for age. Women with endometriosis ( = 6146, mean age ± SD: 40.4 ± 8.0 y) were significantly more likely than controls ( = 24,572) to have a lower BMI and a higher socioeconomic status. After adjusting for BMI and socioeconomic status, endometriosis was significantly associated with infertility (OR = 3.3; 95% CI 3.1-3.5), chronic comorbidities, higher utilization of healthcare services (hospitalization: OR = 2.3; 95% CI 2.1-2.5), pain medications, and antidepressants. Women aged 15-19 y with endometriosis had substantially higher utilization of primary care visits (57.7% vs. 14.4%) and oral contraceptive use (76.9% vs. 9.6%). Direct medical costs associated with endometriosis were higher than those for controls (OR = 1.75; 95% CI 1.69-1.85). Endometriosis is associated with a high burden of comorbidities, increased healthcare resource utilization, and excess costs, particularly for younger patients whose healthcare needs may differ widely from the older population.
Learn More >There is growing appreciation for astrocyte heterogeneity both across and within central nervous system (CNS) regions, as well as between intact and diseased states. Recent work identified multiple astrocyte subpopulations in mature brain. Interestingly, one subpopulation (Population C) was shown to possess significantly enhanced synaptogenic properties in vitro, as compared with other astrocyte subpopulations of adult cortex and spinal cord. Following spinal cord injury (SCI), damaged neurons lose synaptic connections with neuronal partners, resulting in persistent functional loss. We determined whether SCI induces an enhanced synaptomodulatory astrocyte phenotype by shifting toward a greater proportion of Population C cells and/or increasing expression of relevant synapse formation-associated genes within one or more astrocyte subpopulations. Using flow cytometry and RNAscope in situ hybridization, we found that astrocyte subpopulation distribution in the spinal cord did not change to a selectively synaptogenic phenotype following mouse cervical hemisection-type SCI. We also found that spinal cord astrocytes expressed synapse formation-associated genes to a similar degree across subpopulations, as well as in an unchanged manner between uninjured and SCI conditions. Finally, we confirmed these astrocyte subpopulations are also present in the human spinal cord in a similar distribution as mouse, suggesting possible conservation of spinal cord astrocyte heterogeneity across species.
Learn More >Electric shocks may have neurological consequences for the victims. Although the literature on the neurological consequences of electric shocks is limited by retrospective designs, case studies and studies of selected patient groups, previous research provides some evidence of a link between electric shocks, and diseases and symptoms of the central nervous system (CNS)(e.g. epilepsy, migraine and vertigo) and the peripheral nervous system (PNS)(e.g. loss of sensation, neuropathy and muscle weakness). This study aims to employ a register-based, matched cohort study, to investigate whether individuals demonstrate a greater risk of neurological diseases and symptoms of the CNS or PNS in the years following an electrical injury.
Learn More >Although complex pain conditions require an interdisciplinary approach, employment services are rarely provided in pain centers. Individual Placement and Support (IPS) is an effective approach to increase work participation among patients with severe mental illness, and recent evidence suggests that this method may be successfully repurposed to new target groups.We aimed to investigate the effectiveness of IPS integrated with interdisciplinary treatment as usual (TAU) for patients with chronic pain in a tertiary pain center.
Learn More >Non-steroidal anti-inflammatory drugs (NSAIDs) are among the most frequently used drugs both prescribed and over the counter. The long-term cardiovascular safety of NSAIDs in patients with arthritis has engendered controversy. Concerns remain regarding the relative incidence and severity of adverse cardiorenal effects, particularly in arthritis patients with established CV disease, or risk factors for disease as illustrated by the PRECISION trial participants (NCT00346216).
Learn More >The primary objective of this study was to determine the current rate of lead fracture during temporary percutaneous peripheral nerve stimulator (PNS) lead removal at the Mayo Clinic Rochester Division of Pain Medicine.
Learn More >Modern-Type Depression (MTD) is a category of depression that has been studied mainly in Japan; however, no study has attempted to determine its relation to chronic pain.
Learn More >Chronic pain affects approximately 30% of the general population, severely degrades quality of life (especially in older adults) and professional life (inability or reduction in the ability to work and loss of employment), and leads to billions in additional health care costs. Moreover, available painkillers are old, with limited efficacy and can cause significant adverse effects. Thus, there is a need for innovation in the management of chronic pain. Better characterization of patients could help to identify the predictors of successful treatments, and thus, guide physicians in the initial choice of treatment and in the follow-up of their patients. Nevertheless, current assessments of patients with chronic pain provide only fragmentary data on painful daily experiences. Real-life monitoring of subjective and objective markers of chronic pain using mobile health (mHealth) programs can address this issue.
Learn More >Previous studies have demonstrated that weight loss has been shown to improve pain in weight-bearing joints, and more recent studies suggest that weight loss may be accompanied by improvements in pain in non-weight-bearing regions. In previous work, we demonstrated that these symptoms improve substantially in patients with obesity undergoing 12 weeks of a very low-energy diet (VLED) restricted to 800 kcal as part of a weight-loss program. Preclinical models also have shown analgesic effects of calorie restriction. The purpose of the current observational study was to determine the time course and trajectory of improvement in pain and other symptoms, especially during the early phase of a VLED intervention, prior to major weight loss.
Learn More >The purpose of this meta-analysis is to assess whether there is an association between headache disorders and all-cause dementia, Alzheimer's disease (AD), and vascular dementia (VaD).
Learn More >This study aims to systematically evaluate the effect of non-invasive brain stimulation (NIBS) on neuropathic pain (NP) after spinal cord injury and compare the effects of two different NIBS.
Learn More >To assess the prophylactic effect of anodal tDCS of the left motor cortex in patients with resistant chronic migraine (CM) and its long-term maintenance.
Learn More >This review provides an update on sex differences in chronic migraine (CM), with a focus on clinical characteristics, pathophysiology, and treatments.
Learn More >Myofascial pain is a common, but poorly understood multifactorial condition.
Learn More >To describe the most recent findings related to lifestyle behaviors and migraine.
Learn More >Elimination or blocking of astrocytes could ameliorate neuropathic pain in animal models. MiR-125a-5p, expressed in astrocyte derived extracellular vesicles, could mediate astrocyte function to regulate neuron communication. However, the role of miR-125a-5p in DPN (diabetic peripheral neuropathy) remains elusive.
Learn More >Peripheral nerve injuries affect millions of people per year and cause loss of sensation and muscle control alongside chronic pain. The most severe injuries are treated through a nerve autograft; however, donor site morbidity and poor outcomes mean alternatives are required. One option is to engineer nerve replacement tissues to provide a supportive microenvironment to encourage nerve regeneration as an alternative to nerve grafts. Currently, progress is hampered due to a lack of consensus on how to arrange materials and cells in space to maximize rate of regeneration. This is compounded by a reliance on experimental testing, which precludes extensive investigations of multiple parameters due to time and cost limitations. Here, a computational framework is proposed to simulate the growth of repairing neurites, captured using a random walk approach and parameterized against literature data. The framework is applied to a specific scenario where the engineered tissue comprises a collagen hydrogel with embedded biomaterial fibres. The size and number of fibres are optimized to maximize neurite regrowth, and the robustness of model predictions is tested through sensitivity analyses. The approach provides an tool to inform the design of engineered replacement tissues, with the opportunity for further development to multi-cue environments.
Learn More >Chronic noncancer pain (CNCP) affects millions of individuals in the United States but evidence of its prevalence among caregivers of children with special health care needs is sparse. We sought to estimate the prevalence of CNCP and its association with caregiver burden, in a nationally representative sample.
Learn More >Preclinical and clinical research has suggested the existence of pregnancy-associated analgesia, wherein responses to painful stimulation or pain from disease decrease during pregnancy. We combined data from multiple years (2012-2015) of the National Health Interview Survey to examine high-impact pain by Hispanic ethnicity and race in women with no prior pregnancy, during pregnancy, and previously pregnant. High-impact pain was less common for women during pregnancy (10.3%; 95% confidence interval [CI]: 7.0%-13.7%) than it was for women who had never been pregnant (13.7%; 95% CI: 12.8%-14.5%) and for women who had previously been pregnant (19.8%; 95% CI: 16.0%-23.7%). However, when we examined the data by Hispanic ethnicity and race, we found that non-Hispanic White (NHW) women were less likely to report high-impact pain during pregnancy, but non-Hispanic Black (NHB) women and Hispanic White women were not. In women who reported no prior pregnancy, NHW women were most likely to report high-impact pain, followed by NHB women and Hispanic women. In analyses, we found that while menstrual problems were associated with increased odds of having high-impact pain, an interaction was not observed between menstrual problems and race/ethnicity ( = 0.48). This cross-sectional study presents a nationally representative examination of the prevalence of high-impact pain across pregnancy status. Using a nationally representative sample of women, we have demonstrated that the prevalence of high-impact pain varies across pregnancy status and that race/ethnicity and the presence of menstrual problems independently affect this prevalence.
Learn More >Understanding how pharmaceutical opioids and antipyretic analgesics interact with the immune system potentially has major clinical implications for management of patients with infectious diseases and surgical and critical care patients. An electronic search was carried out on MEDLINE, EMBASE, PsycINFO, CENTRAL and the Cochrane library to identify reports describing the immunomodulatory effects of opioid analgesics and antipyretic analgesics, and their effects in infectious diseases. In adaptive immunity, nonsteroidal anti-inflammatory drugs have divergent effects: augmenting cell-mediated immunity but inhibiting humoral immunity. Nonsteroidal anti-inflammatory drugs have demonstrated a beneficial role in Mycobacterium tuberculosis infection and histoplasmosis in animals, and may be plausible adjuvants to antimicrobial agents in these diseases. There is a need to evaluate these findings rigorously in human clinical trials. There is preliminary evidence demonstrating antiviral effects of indomethacin in SARS CoV-2 in vitro; however, uncertainty regarding its clinical benefit in humans needs to be resolved in large clinical trials. Certain opioid analgesics are associated with immunosuppressive effects, with a developing understanding that fentanyl, morphine, methadone and buprenorphine suppress innate immunity, whilst having diverse effects on adaptive immunity. Morphine suppresses key cells of the innate immunity and is associated with greater risk of infection in the postsurgical setting. Efforts are needed to achieve adequate analgesia whilst avoiding suppression of the innate immunity in the immediate postoperative period caused by certain opioids, particularly in cancer surgery.
Learn More >Chronic low back pain (CLBP) is among the most common types of pain in adults. Currently, injections and analgesic and nonsteroidal anti-inflammatory drugs are often provided for patients with CLBP. However, their effectiveness remains questionable, and the safest approach to CLBP remains debated. Meditation-based therapies constitute an alternative treatment with high potential for widespread availability. We evaluated the applicability of meditation-based therapies for CLBP management.
Learn More >Chronic pain is a prevalent and burdensome problem within the Canadian health care system, where the gold standard treatment occurs at multidisciplinary pain facilities. Patient intake questionnaires (PIQs) are standard practice for obtaining health information, with many patients including free-text (e.g., writing in margins of questionnaires) on their PIQs.
Learn More >Alpha-calcitonin gene-related peptide (α-CGRP) is a vasodilator neuropeptide of the calcitonin gene family. Pharmacological and gene knock-out studies have established a significant role of α-CGRP in normal and pathophysiological states, particularly in cardiovascular disease and migraines. α-CGRP knock-out mice with transverse aortic constriction (TAC)-induced pressure-overload heart failure have higher mortality rates and exhibit higher levels of cardiac fibrosis, inflammation, oxidative stress, and cell death compared to the wild-type TAC-mice. However, administration of α-CGRP, either in its native- or modified-form, improves cardiac function at the pathophysiological level, and significantly protects the heart from the adverse effects of heart failure and hypertension. Similar cardioprotective effects of the peptide were demonstrated in pressure-overload heart failure mice when α-CGRP was delivered using an alginate microcapsules-based drug delivery system. In contrast to cardiovascular disease, an elevated level of α-CGRP causes migraine-related headaches, thus the use of α-CGRP antagonists that block the interaction of the peptide to its receptor are beneficial in reducing chronic and episodic migraine headaches. Currently, several α-CGRP antagonists are being used as migraine treatments or in clinical trials for migraine pain management. Overall, agonists and antagonists of α-CGRP are clinically relevant to treat and prevent cardiovascular disease and migraine pain, respectively. This review focuses on the pharmacological and therapeutic significance of α-CGRP-agonists and -antagonists in various diseases, particularly in cardiac diseases and migraine pain.
Learn More >All critically ill adult patients in intensive care units (ICU) typically experience pain. Critically ill adults suffer pain of different intensities. It depends on individual characteristics, specific procedural interventions, and underlying diseases. Inadequate management of acute pain is a risk factor for the emergence of chronic pain, where the incidence is up to 33% into the ICU survivor population. For the management of pain, agitation, and delirium, several coexisting clinical practice guidelines have been published. The first problem is that the patient recovered in intensive care unit should not be able to communicate its pain state. Opioids are the analgesic drugs of choice in critically ill patients with non-neuropathic pain. All intravenous opioids have the same effects, respecting the equianalgesic table. Observational research has shown that opioids are the main analgesic treatment in over 80% of mechanically ventilated patients. It is interesting that opioid consumption in an ICU and the memory of painful experience are linked to the development of post-traumatic stress disorder after ICU discharge. In order to reduce the side effects and maintain analgesia, it is useful to associate adjuvant medications with opioids. An opportunity to improve patients' experience in an ICU is to manage pain through multimodal approaches.
Learn More >Voltage-gated sodium channels (Na) are responsible for the initiation and propagation of action potentials in excitable cells. From pain to heartbeat, these integral membrane proteins are the ignition stations for every sensation and action in human bodies. They are large (>200 kDa, 24 transmembrane helices) multi-domain proteins that couple changes in membrane voltage to the gating cycle of the sodium-selective pore. Na mutations lead to a multitude of diseases – including chronic pain, cardiac arrhythmia, muscle illnesses, and seizure disorders – and a wide variety of currently used therapeutics block Na Despite this, the mechanisms of action of Na blocking drugs are only modestly understood at this time and many questions remain to be answered regarding their state- and voltage-dependence, as well as the role of the hydrophobic membrane access pathways, or fenestrations, in drug ingress or egress. Na fenestrations, which are pathways that connect the plasma membrane to the central cavity in the pore domain, were discovered through functional studies more than 40 years ago and once thought to be simple pathways. A variety of recent genetic, structural, and pharmacological data, however, shows that these fenestrations are actually key functional regions of Na that modulate drug binding, lipid binding, and influence gating behaviors. We discovered that some of the disease mutations that cause arrhythmias alter amino acid residues that line the fenestrations of Nav1.5. This indicates that fenestrations may play a critical role in channel's gating, and that individual genetic variation may also influence drug access through the fenestrations for resting/inactivated state block. In this review, we will discuss the channelopathies associated with these fenestrations, which we collectively name "Fenestropathy," and how changes in the fenestrations associated with the opening of the intracellular gate could modulate the state-dependent ingress and egress of drugs binding in the central cavity of voltage gated sodium channels.
Learn More >Pain is an unpleasant sensory and emotional experience that exists all over the world and has a negative effect on people's ability to engage in valuable life activities. The present study was conducted aiming to investigate the mediating role of coping strategies and emotion regulation in the relationship between pain acceptance and pain anxiety. The research design was descriptive, and the sample consisted of 428 students selected via purposive sampling. Pain Anxiety Symptoms Scale (PASS-20), Chronic Pain Acceptance Questionnaire-8 (CPAQ-8), Ways of Coping Questionnaire (WCQ), The Multidimensional Pain Inventory (MPI), and Emotion Regulation Questionnaire (ERQ) were used as research tools. The results obtained from the correlation revealed that there is a significant relationship between pain acceptance and pain anxiety, coping strategies, and emotion regulation. Structural Equation Modeling (SEM) showed that coping strategies and emotion regulation are able to mediate the relationship between pain acceptance and pain anxiety. In general, results revealed that adaptive coping strategies can be effective in coping with pain; emotional components play an important role in this regard. These results demonstrate the importance of attitude and self-regulation in coping with pain, and suggest that people can expand their adaptation to pain by assessing the situation and adopting an effective coping style.
Learn More >This study investigated whether a new sustained-release (SR) pregabalin formulation is non-inferior to immediate-release (IR) pregabalin in alleviating peripheral neuropathic pain in Korean patients.
Learn More >Neuropathic pain is a type of chronic pain with complex mechanisms, and current treatments have shown limited success in treating patients suffering from chronic pain. Accumulating evidence has shown that the pathogenesis of neuropathic pain is mediated by the plasticity of excitatory neurons in the dorsal horn of the spinal cord, which provides insights into the treatment of hyperalgesia. In this study, we found that Schnurri-2 (Shn2) was significantly upregulated in the L4-L6 segments of the spinal cord of C57 mice with spared nerve injury, which was accompanied by an increase in GluN2D subunit and glutamate receptor subunit 1 (GluR1) levels. Knocking down the expression of Shn2 using a lentivirus in the spinal cord decreased the GluN2D subunit and GluR1 levels in spared nerve injury mice and eventually alleviated mechanical allodynia. In summary, Shn2 regulates neuropathic pain, promotes the upregulation of GluN2D in glutamatergic neurons and increases the accumulation of GluR1 in excitatory neurons. Taken together, our study provides a new underlying mechanism for the development of neuropathic pain.
Learn More >Diabetic neuropathic pain (DNP) is highly common in diabetes patients. P2X receptors play critical roles in pain sensitization. We previously showed that elevated P2X3 expression in dorsal root ganglion (DRG) contributes to DNP. However, the role of other P2X receptors in DNP is unclear. Here, we established the DNP model using a single high-dose streptozotocin (STZ) injection and investigated the expression of P2X genes in the DRG. Our data revealed elevated P2X2, P2X4, and P2X7 mRNA levels in DRG of DNP rats. The protein levels of P2X4 and P2X7 in DNP rats increased, but the P2X2 did not change significantly. To study the role of P2X4 and P2X7 in diabetes-induced hyperalgesia, we treated the DNP rats with TNP-ATP (2',3'-O-(2,4,6-trinitrophenyl)-adenosine 5'-triphosphate), a nonspecific P2X1-7 antagonist, and found that TNP-ATP alleviated thermal hyperalgesia in DNP rats. 2 Hz electroacupuncture is analgesic against DNP and could downregulate P2X4 and P2X7 expression in DRG. Our findings indicate that P2X4 and P2X7 in L4-L6 DRGs contribute to diabetes-induced hyperalgesia, and that EA reduces thermal hyperalgesia and the expression of P2X4 and P2X7.
Learn More >The influence of the stimulation frequency on the outcomes of dorsal root ganglion stimulation (DRG-S) to treat pain is not well understood. It is assumed that specific neural components dedicated to different tasks in the DRG can be preferably influenced at specific frequencies. The identification of frequencies designed for the type of pain and the ratio of neuropathic versus nociceptive pain might improve overall pain control and open new indications in DRG-S.
Learn More >Cannabis, as a natural medicinal remedy, has long been used for palliative treatment to alleviate the side effects caused by diseases. Cannabis-based products isolated from plant extracts exhibit potent immunoregulatory properties, reducing chronic inflammatory processes and providing much needed pain relief. They are a proven effective solution for treatment-based side effects, easing the resulting symptoms of the disease. However, we discuss the fact that cannabis use may promote the progression of a range of malignancies, interfere with anti-cancer immunotherapy, or increase susceptibility to viral infections and transmission. Most cannabis preparations or isolated active components cause an overall potent immunosuppressive impact among users, posing a considerable hazard to patients with suppressed or compromised immune systems. In this review, current knowledge and perceptions of cannabis or cannabinoids and their impact on various immune-system components will be discussed as the "two sides of the same coin" or "double-edged sword", referring to something that can have both favorable and unfavorable consequences. We propose that much is still unknown about adverse reactions to its use, and its integration with medical treatment should be conducted cautiously with consideration of the individual patient, effector cells, microenvironment, and the immune system.
Learn More >The aim of this analysis is to determine whether regular physical activity is associated with less analgesic use in men and women suffering from headache disorders based on population-based cross-sectional data.
Learn More >Neuropathic pain is a form of chronic pain arising from damage of the neural cells that sense, transmit or process sensory information. Given its growing prevalence and common refractoriness to conventional analgesics, the development of new drugs with pain relief effects constitutes a prominent clinical need. In this respect, drugs that reduce activity of sensory neurons by modulating ion channels hold the promise to become effective analgesics. Here, we evaluated the mechanical antinociceptive effect of IQM-PC332, a novel ligand of the multifunctional protein downstream regulatory element antagonist modulator (DREAM) in rats subjected to chronic constriction injury of the sciatic nerve as a model of neuropathic pain. IQM-PC332 administered by intraplantar (0.01-10 µg) or intraperitoneal (0.02-1 µg/kg) injection reduced mechanical sensitivity by ≈100% of the maximum possible effect, with ED of 0.27 ± 0.05 µg and 0.09 ± 0.01 µg/kg, respectively. Perforated-patch whole-cell recordings in isolated dorsal root ganglion (DRG) neurons showed that IQM-PC332 (1 and 10 µM) reduced ionic currents through voltage-gated K channels responsible for A-type potassium currents, low, T-type, and high voltage-activated Ca channels, and transient receptor potential vanilloid-1 (TRPV1) channels. Furthermore, IQM-PC332 (1 µM) reduced electrically evoked action potentials in DRG neurons from neuropathic animals. It is suggested that by modulating multiple DREAM-ion channel signaling complexes, IQM-PC332 may serve a lead compound of novel multimodal analgesics.
Learn More >Supraspinal mechanisms of pain are increasingly understood to underlie neuropathic ocular conditions previously thought to be exclusively peripheral in nature. Isolating individual causes of centralized chronic conditions and differentiating them is critical to understanding the mechanisms underlying neuropathic eye pain and ultimately its treatment. Though few functional imaging studies have focused on the eye as an end-organ for the transduction of noxious stimuli, the brain networks related to pain processing have been extensively studied with functional neuroimaging over the past 20 years. This article will review the supraspinal mechanisms that underlie pain as they relate to the eye.
Learn More >Transient receptor potential melastatin type 8 (TRPM8) is a target for the treatment of different physio-pathological processes. While TRPM8 antagonists are reported as potential drugs for pain, cancer, and inflammation, to date only a limited number of chemotypes have been investigated and thus a limited number of compounds have reached clinical trials. Hence there is high value in searching for new TRPM8 antagonistic to broaden clues to structure-activity relationships, improve pharmacological properties and explore underlying molecular mechanisms. To address this, the EDASA Scientific in-house molecular library has been screened in silico, leading to identifying twenty-one potentially antagonist compounds of TRPM8. Calcium fluorometric assays were used to validate the in-silico hypothesis and assess compound selectivity. Four compounds were identified as selective TRPM8 antagonists, of which two were dual-acting TRPM8/TRPV1 modulators. The most potent TRPM8 antagonists ( and ) underwent molecular modelling studies to highlight key structural features responsible for drug-protein interaction. The two compounds were also investigated by patch-clamp assays, confirming low micromolar potencies. The most potent compound (, IC 1.25 ± 0.26 μM) was then profiled in vivo in a cold allodinya model, showing pharmacological efficacy at 30 μM dose. The new chemotypes identified showed remarkable pharmacological properties paving the way to further investigations for drug discovery and pharmacological purposes.
Learn More >Neck pain is a prevalent and costly problem, but its underlying mechanisms are poorly understood. Neuroimaging studies show alterations in brain morphometry in chronic musculoskeletal pain, but reports on neck pain are scarce.
Learn More >Pain is undesirable, whether it is a symptom of mild or severe illness or instead indicates disorder in the nervous system's ability to perceive and process sensory information. Nonetheless, pain is part of the body's ability to defend itself and promote its own survival-this is its fundamental evolutionary function. This normal expression of pain is not limited to what is considered useful because it alerts us to the initiation of illness. It also applies to pain that continues when illness or noxious stimuli persist. However, the parameters of what is here termed functional pain are not fully understood and are seldom explicitly the focus of research. This paper posits that failure to appreciate the functional role of pain in research has had significant unintended consequences and may be contributing to inconsistent research findings. To that end, the paper describes the misclassification issue at the core of chronic pain research-whether a given pain reflects functional or pathological processes-and discusses research areas where reconsidering the functional role of pain may lead to advancements.
Learn More >Pharmacokinetic-pharmacodynamic modelling and simulation can facilitate understanding and prediction of exposure-response relationships in children with acute or chronic pain. The pharmacokinetics of diamorphine (diacetylmorphine, heroin), a strong opioid, remain poorly quantified in children and dose is often guided by clinical acumen. This tutorial demonstrates how a model to describe intranasal and intravenous diamorphine pharmacokinetics can be fashioned from a model for diamorphine disposition in adults and a model describing morphine disposition in children. Allometric scaling and maturation models were applied to clearances and volumes to account for differences in size and age between children and adults. The utility of modelling and simulation to gain insight into the analgesic exposure-response relationship is demonstrated. The model explains reported observations, can be used for interrogation, interpolated to determine equianalgesia and inform future clinical studies. Simulation was used to illustrate how diamorphine is rapidly metabolized to morphine via its active metabolite 6-monoacetylmorphine, which mediates an early dopaminergic response accountable for early euphoria. Morphine formation is then responsible for the slower, prolonged analgesic response. Time-concentration profiles of diamorphine and its metabolites reflected disposition changes with age and were used to describe intravenous and intranasal dosing regimens. These indicated that morphine exposure in children after intranasal diamorphine 0.1 mg.kg was similar to that after intranasal diamorphine 5 mg in adults. A target concentration of morphine 30 μg.L can be achieved by a diamorphine intravenous infusion in neonates 14 μg.kg .h , in a 5-year-old child 42 μg.kg .h and in an 15 year-old-adolescent 33 μg.kg .h .
Learn More >Diabetic neuropathy is the most entrenched complication of diabetes. Usually, it affects the distal foot and toes, which then gradually approaches the lower part of the legs. Diabetic foot ulcer (DFU) could be one of the worst complications of diabetes mellitus. Long-term diabetes leads to hyperglycemia, which is the utmost contributor to neuropathic pain. Hyperglycemia causing an upregulation of voltage-gated sodium channels in the dorsal root ganglion (DRG) was often observed in models of neuropathic pain. DRG opening frequency increases intracellular sodium ion levels, which further causes increased calcium channel opening and stimulates other pathways leading to diabetic peripheral neuropathy (DPN). Currently, pain due to diabetic neuropathy is managed antidepressants, opioids, gamma-aminobutyric acid (GABA) analogs, and topical agents such as capsaicin. Despite the availability of various treatment strategies, the percentage of patients achieving adequate pain relief remains low. Many factors contribute to this condition, such as lack of specificity and adverse effects such as light-headedness, languidness, and multiple daily doses. Therefore, nanotechnology outperforms in every aspect, providing several benefits compared to traditional therapy such as site-specific and targeted drug delivery. Nanotechnology is the branch of science that deals with the development of nanoscale materials and products, even smaller than 100 nm. Carriers can improve their efficacy with reduced side effects by incorporating drugs into the novel delivery systems. Thus, the utilization of nanotechnological approaches such as nanoparticles, polymeric nanoparticles, inorganic nanoparticles, lipid nanoparticles, gene therapy (siRNA and miRNA), and extracellular vesicles can extensively contribute to relieving neuropathic pain.
Learn More >Chronic pain affects 1 in 5 youth, many of whom manage their pain using a biopsychosocial approach. The COVID-19 pandemic has impacted the way that healthcare is delivered. As part of a larger program of research, this study aimed to understand the impact of the pandemic on pediatric chronic pain care delivery including impact on patients' outcomes, from the perspective of pediatric healthcare providers. A qualitative descriptive study design was used and 21 healthcare providers from various professional roles, clinical settings, and geographic locations across Canada were interviewed. Using a reflexive thematic analysis approach 3 themes were developed: (1) duality of pandemic impact on youth with chronic pain (i.e., how the pandemic influenced self-management while also exacerbating existing socioeconomic inequalities); (2) changes to the healthcare system and clinical practices (i.e., triaging and access to care); (3) shift to virtual care (i.e., role of institutions and hybrid models of care). These findings outline provider perspectives on the positive and negative impacts of the pandemic on youth with chronic pain and highlight the role of socioeconomic status and access to care in relation to chronic pain management during the pandemic in a high-income country with a publicly funded healthcare system.
Learn More >In the rapidly evolving field of spinal cord stimulation (SCS), measures of treatment effects are needed to help understand the benefits of new therapies. The present article elaborates the number needed to treat (NNT) concept and applies it to the SCS field. We reviewed the basic theory of the NNT, its calculation method, and its application to historical controlled trials of SCS. We searched the literature for controlled studies with ≥20 implanted SCS patients with chronic axial back and/or leg pain followed for ≥3 months and a reported responder rate defined as ≥50% pain relief. Relevant data necessary to estimate the NNT were extracted from the included articles. In total, 12 of 1616 records were eligible for inclusion. The records reported 10 clinical studies, including 7 randomized controlled trials, 2 randomized crossover trials, and 1 controlled cohort study. The studies investigated traditional SCS and more recently developed SCS modalities, including 10 kHz SCS. In conclusion, the NNT estimate may help SCS stakeholders better understand the effect size difference between compared treatments; however, interpretation of any NNT should take into account its full context. In addition, comparisons across trials of different therapies should be avoided since they are prone to interpretation biases.
Learn More >There is a lack of good quality evidence regarding the effectiveness of transcutaneous electrical nerve stimulation (TENS) for chronic musculoskeletal pain, including chronic low back pain. High quality randomised controlled trials (RCTs) have been called for to establish effectiveness over and above placebo and some guidance has already been offered regarding the design of such trials. This article expands the discussion regarding the design of future TENS trials. There is qualitative evidence of the complexity of TENS as an intervention which should be considered in future TENS evaluations. This complexity includes multiple benefits reported by patients, depending on their chosen contexts of TENS use. The ideal content and delivery of support for patients to optimise TENS use also lacks consensus. There is no evidence that a TENS education package has been designed to support the complex set of behaviours and choices which experienced users suggest are required to optimise TENS benefits. Finally, clinical and research outcomes have not been contextualised and related to the specific strategies of use. We suggest that research is required to develop consensus about the content and delivery of training in TENS use for patients who live with pain, informed by the experience of patients, clinicians, and researchers. Once a consensus about the content of TENS training has been reached, there is then a need to develop a TENS training course (TTC) based on this content. An effective and acceptable TTC is needed to develop the knowledge and skills required to optimise TENS use, supporting patients to build confidence in using TENS in everyday life situations with the aim of reducing the impact of chronic pain on function and quality of life. Further research is required to extend the evidence base regarding appropriate, contextualised TENS patient-reported outcomes.
Learn More >Conservative treatments for early osteoarthritis (OA) of the knee included the use of non-steroid anti-inflammatory drugs (NSAIDs) and intra-articular hyaluronic acid (HA) injection. Recently, several animal studies reported that extracorporeal shockwave therapy (ESWT) demonstrated chondroprotective effects on knee OA. The present study compared the efficacy of oral NSAIDs, HA injection, and noninvasive ESWT for early OA of the knee. Forty-five patients with early knee OA were randomized into three groups. NSAIDs group received celecoxib 200 mg daily for 3 weeks. HA group received intra-articular injection of HA once a week for 3 weeks. ESWT group received ESWT for 3 sessions at bi-weekly interval. All patients were followed up for one year. Evaluations included the visual analogue scale (VAS) score, serum enzyme-linked immunosorbent assay (ELISA), plain radiography, dual-energy X-ray absorptiometry (DEXA), and magnetic resonance imaging (MRI). In addition, the functional scores were performed including, WOMAC (Western Ontario and McMaster Universities Arthritis Index) score, KOOS (knee injury and osteoarthritis outcome) score, and IKDC (International Knee Documentation Committee) score. All three groups showed significant improvement in VAS and functional scores as well as in the collected one-year follow-up data after treatments. ESWT group had better pain relief than NSAIDs and HA groups. ESWT group had better therapeutic effects in the functional scores than NSAIDs and HA groups. The bone mineral density (BMD) of proximal tibia is significantly increased after ESWT than others. In the serum ELISA, ESWT inhibited the expression of COMP in knee OA patients as compared with NSAIDs and HA groups. The parameters of MRI showed no significant differences between three groups after treatments. ESWT and intra-articular HA injection showed comparable results than NSAIDs. ESWT was superior in pain relief than HA and NSAIDs. The results demonstrated that ESWT was an effective and alternative therapy than HA and NSAIDs for early osteoarthritis of the knees.
Learn More >Headache is the first cause of consultation in neurology, and one of the most frequent reasons for consultation in general medicine. Migraine is one of the most common, prevalent, and socioeconomically impactful disabling primary headache disorders. Neuroticism can be conceptualized as a disposition to suffer anxiety and emotional disorders in general. Neuroticism has been associated with various mental and physical disorders (e.g., chronic pain, depression), including migraine. With the aim to explore in depth the relationship between migraine and neuroticism, and contribute to the understanding of this relation in order to provide a better treatment for migraine patients based on a personalized and more comprehensive approach, a scoping review was performed using PubMed, Scopus, and Web of Science. Databases were searched independently by the two researchers, reaching a final set of 18 articles to be included. The search terms were: migraine and neuroticism. Neuroticism seems to be highly prevalent in migraine patients. Findings reveal that migraine patients with comorbid depression and anxiety showed higher levels of neuroticism. Depression has been associated with an increased risk of transformation from episodic to chronic migraine whereas neuroticism might be a mediator factor. Neuroticism also might be a mediator factor between childhood maltreatment and migraine. The revision conducted confirms that: (1) Migraine patients usually have a higher level of neuroticism and vulnerability to negative affect, compared to non-migraineurs and tension-type headache patients. (2) Neuroticism is associated with migraine. Nonetheless, more research is needed to clarify potential moderators of this relationship and the role of neuroticism itself in this disease. This knowledge might be useful in order to promote a better management of negative emotions as part of intervention programs in migraine.
Learn More >Postcraniotomy headache (PCH) is a highly underappreciated and very common adverse event following craniotomy.
Learn More >To systematically review the effects of physical therapy given by telerehabilitation on pain and disability in individuals with shoulder pain.
Learn More >Neuropathic pain is one of the primary forms of chronic pain and is the consequence of the somatosensory system's direct injury or disease. It is a relevant public health problem that affects about 10% of the world's general population. In neuropathic pain, alteration in neurotransmission occurs at various levels, including the dorsal root ganglia, the spinal cord, and the brain, resulting from the malfunction of diverse molecules such as receptors, ion channels, and elements of specific intracellular signaling pathways. In this context, there have been exciting advances in elucidating neuropathic pain's cellular and molecular mechanisms in the last decade, including the possible role that long non-coding RNAs (lncRNAs) may play, which open up new alternatives for the development of diagnostic and therapeutic strategies for this condition. This review focuses on recent studies associated with the possible relevance of lncRNAs in the development and maintenance of neuropathic pain through their actions on the functional expression of ion channels. Recognizing the changes in the function and spatio-temporal patterns of expression of these membrane proteins is crucial to understanding the control of neuronal excitability in chronic pain syndromes.
Learn More >The first human applications of ultrasound in medicine date back to 1939, when Reimar Pohlmann (Berlin, Germany) published data on therapy of neuralgia with ultrasound […].
Learn More >Prehospital Pain Management: Overview and Potential Improvements Pain is a frequent issue in the prehospital setting. Rapid and adequate analgesia has a positive effect on the physiological and psychological condition of patients. However, up to 43 % of patients still suffer insufficient analgesia. Several studies have identified some factors that contribute to this problem; these factors can be patient- and intervention-specific or dependent on the staff on duty. In order to improve prehospital analgesia in the future, structural and organizational changes as well as the implementation of new methods and therapies are essential.
Learn More >To summarize the characteristics of home practice adherence in patients with chronic pain randomized to a 10-week group mind-body activity program with () and without () a digital monitoring device, and test the association between home practice adherence and improvement in physical and emotional treatment outcomes. Data were collected in a pilot randomized controlled trial (RCT) of the ( = 41) and ( = 41) programs. Participants submitted weekly home practice logs depicting their daily physical activity and practice of relaxation and gratitude skills. Participants completed assessments of physical (patient-reported, performance-based, and accelerometer-measured) and emotional function outcomes both before and after the programs. Participants in both programs were combined due to the identical session and home practice content. Participants reported engaging in physical activity on average 30.62 days (SD = 20.28, 48.6% of intervention days), relaxation skill practice on average 29.87 days (SD = 21.16, 47.4% of intervention days), and gratitude practice on average 32.10 days (SD = 22.12, 51.0% of intervention days). The average duration of physical activity and relaxation skill practice were 44.40 min a day (SD = 59.44) and 11.15 min a day (SD = 12.00), respectively. The duration of physical activity was significantly associated with decrease depression symptoms ( = 0.049, η = 0.056). No other association was found between home practice and change in outcomes. Patients with chronic pain are generally able and willing to engage in home practice during a mind-body activity intervention. Emphasizing longer duration of physical activity practice may contribute to an improvement in depression. Future fully powered RCTs with rigorous assessment of home practice adherence and dose-response designs may further elucidate the role of home practice in improvements in treatment outcomes. NCT03412916.
Learn More >Research regarding daily acute pain and its correlates has primarily been conducted with adolescents who have had major surgery or musculoskeletal pain, restraining efforts towards adapting interventions for adolescents with other sources of acute pain. We explored the trajectories and correlates of pain intensity. Adolescents with an opioid prescription to treat acute pain (N = 157) completed demographic questions, and the PROMIS pediatric depression and anxiety subscales. A 10-day daily diary assessed pain intensity, pain interference, sleep quality, and opioid use. Three trajectories of pain intensity emerged: (1) slow decreases in pain, (2) rapid decreases in pain, and (3) stable or slight increases in pain. Teens with stable pain demonstrated the greatest anxiety levels. Higher sleep quality predicted lower next day pain intensity and pain interference, when controlling for opioid use. Future research should employ intensive longitudinal methodology to further guide intervention development and prevent the transition to chronic pain.
Learn More >To examine predictors and consequences of prescription opioid use among a cohort of women living with HIV (WLWH) and women without HIV from 2000 to 2019. The Women's Interagency HIV Study is a multisite, prospective cohort study. Cumulative proportion of visits with prescription opioid use was categorized as follows: minimal (0%-9%), intermediate (10%-39%), and chronic (>40%). Logistic regression examined independent predictors, and proportional hazards regression estimated unadjusted and adjusted hazards of all-cause mortality, comparing intermediate and chronic prescription opioid use with minimal use. Annual prevalence of prescription opioid use significantly increased from 12.6% to 19.3% from 2000 to 2019 ( < 0.0001). Prescription opioid use was minimal in 75%, intermediate in 16%, and chronic in 9% of women. WLWH had 56% higher odds of chronic prescription opioid use compared with women without HIV. Even after adjusting for quality-of-life scores including ratings of pain, women with intermediate and chronic prescription opioid use had greater odds of being sexual minorities (lesbian or bisexual), unemployed, and were more likely to report benzodiazepine and nonprescription substance use compared with those with minimal use. Intermediate and chronic prescription opioid use were each associated with an almost 1.5-fold increased risk of all-cause mortality. Despite federally mandated opioid prescribing guidelines, prescription opioid use and related mortality significantly increased in women experiencing physical and psychosocial vulnerabilities. The higher mortality rate found among prescription opioid users may reflect the many underlying chronic medical and psychosocial conditions for which these opioids were prescribed, as well as complications of opioids themselves. Findings underscore the need for non-opioid and nonpharmacological interventions for chronic pain, particularly in sexual minorities and WLWH. Avoiding concurrent use of opioids with benzodiazepines and nonprescription drugs might reduce mortality. Clinical Trial Registration Number: NCT00000797.
Learn More >Socioeconomic deprivation is shown to be linked to chronic lower back pain. However, a comprehensive approach to identify key components contributing to pain outcomes using a biopsychosocial model incorporating social determinants of health is needed to develop and tailor successful strategies for mitigating chronic pain development and persistence. We aimed to develop and validate an instrument (the HELP survey) to assess themes characterized by a combination of social determinants of health and the biopsychosocial model in an underserved population. The HELP survey was developed as part of an observational study determining the influence of health disparities on chronic pain interference, The Neighborhood of Pain: Health Disparity Influence on Level of Chronic Pain Interference study (HELP).
Learn More >Microvascular decompression (MVD) has been increasingly performed in elderly patients with trigeminal neuralgia (TN). We conducted a meta-analysis to compare the effectiveness and safety of MVD in elderly and young patients with TN.
Learn More >Painful diabetic neuropathy (PDN) is a prevalent and debilitating condition, characterized by severe burning, tingling, and lancinating pain usually located in the distal lower extremities. In addition to manifesting with severe pain, PDN may also be associated with poor quality of life and sleep, mood disorders, burns, falls, and social withdrawal. The authors appraised the current body of literature for evidence on neuromodulation interventions for PDN.
Learn More >Molecular mechanisms underlying trigeminal neuralgia (TN) have been poorly understood. Recently, different biomarkers have been studied in several chronic neuropathic diseases or in neuronal damage, but their role in TN has not yet been investigated. Here, we firstly analyzed the serum levels of the neuron-specific enolase (NSE) (as an index of neuronal tissue damage) in TN patients submitted to surgical treatment. Different cytokines and interleukins related to inflammation were also studied.
Learn More >The advancement of digital health provides strategic and cost-effective opportunities for the progression of health care in children and adolescents. It is important for clinicians to be aware of the potential of emerging pain outcome measures and employ evidence-based tools capable of reliably tracking acute and chronic pain over time. The main emerging pain outcome measures for children and adolescents were examined. Overall, seven main texts and their corresponding digital health technologies were included in this study. The main findings indicated that the use of emerging digital health is able to reduce recall bias and can improve the real time paediatric data capture of acute and chronic symptoms. This literature review highlights new developments in pain management in children and adolescents and emphasizes the need for further research to be conducted on the use of emerging technologies in pain management. This may include larger scale, multicentre studies to further assess validity and reliability of these tools across various demographics. The privacy and security of mHealth data must also be carefully evaluated when choosing health applications that can be introduced into daily clinical settings.
Learn More >Biallelic mutations in sorbitol dehydrogenase (SORD) have been recently identified as a common cause of recessive axonal Charcot-Marie-Tooth neuropathy (CMT2). We aimed to assess a novel long-read sequencing approach to overcome current limitations in SORD neuropathy diagnostics due to the SORD2P pseudogene and the phasing of biallelic mutations in recessive disease.
Learn More >Current evidence suggests that cannabinoids are safe with minimal side effects and are effective in managing chronic pain. Data also show that medical marijuana (MM) may improve quality of life (QoL) among patients. However, there are little data showing the health-related QoL (HRQoL) benefit in MM patients using it for pain. The purpose of this study was to determine if there is a relationship between HRQol and MM use in patients using it to relieve pain.
Learn More >More patients are turning to medical marijuana as an alternative treatment, yet there are apparent knowledge gaps on the risk benefit of medical marijuana for a variety of indications. This study aimed to determine the priorities for medical marijuana research from the perspective of multiple stakeholders including patients, clinicians, and industry representatives.
Learn More >For centuries, cannabis and its components have been used to manage a wide variety of symptoms associated with many illnesses. Gastrointestinal (GI) diseases are no exception in this regard. Individuals suffering from inflammatory bowel disease (IBD) are among those who have sought out the ameliorating properties of this plant. As legal limitations of its use have eased, interest has grown from both patients and their providers regarding the potential of cannabis to be used in the clinical setting. Similarly, a growing number of animal and human studies have been undertaken to evaluate the impact of cannabis and cannabinoid signaling elements on the natural history of IBD and its associated complications. There is little clinical evidence supporting the ability of cannabis or related products to treat the GI inflammation underlying these disorders. However, 1 recurring theme from both animal and human studies is that these agents have a significant impact on several IBD-related symptoms, including abdominal pain. In this review, we discuss the role of cannabis and cannabinoid signaling in visceral pain perception, what is currently known regarding the efficacy of cannabis and its derivatives for managing pain, related symptoms and inflammation in IBD, and what work remains to effectively utilize cannabis and its derivatives in the clinical setting.
Learn More >Intervertebral disc degeneration is a progressive and chronic disease, usually manifesting as low back pain. This study aimed to screen effective biomarkers for medical practice as well as figuring out immune infiltration situations between circulation and intervertebral discs. Gene expression profiles of GSE124272 was included for differentially analysis, WGCNA and immune infiltration analysis from GEO database, and other GSE series were used as validation datasets. A series of validation methods were conducted to verify the robustness of hub genes, such as principal component analysis, machine learning models, and expression verification. Lastly, nomogram was established for medical practice. 10 genes were commonly screened combination of DEGs, WGCNA analysis and lipid metabolism related genes. Furthermore, 3 hub gens CYP27A1, FAR2, CYP1B1 were chosen for subsequent analysis based on validation of different methods. GSEA analysis discovered that neutrophil extracellular traps formation and NOD-like receptor signaling pathway was activated during IDD. Immune infiltration analysis demonstrated that the imbalance of neutrophils and γδT cells were significantly correlated with IDD progression. Nomogram was established based on CYP27A1, FAR2, CYP1B1 and age, the calibration plot confirmed the stability of our model. CYP27A1, FAR2, CYP1B1 were considered as hub lipid metabolism related genes (LMRGs) in the development of IDD, which were regarded as candidate diagnostic biomarkers especially in circulation. The effects are worth expected in the early diagnosis of IDD through detecting these genes in blood.
Learn More >Translational research has changed the understanding of atopic dermatitis (AD) pathogenesis beyond the basic mechanisms of immunology. The study in patients of rational therapies based on targeted therapies (biologicals) provides valuable information from the patient and provides lessons of clinical immunology on clinically relevant mechanism of AD pathogenesis. AD features such as skin barrier defect, skin dysbiosis, and pruritus share a common abnormal adaptive immune response process. Skin-homing CLA+CD4+ memory T-cells produce IL-4, IL-13, and IL-31 which are key mediators in AD pathogenesis. Lessons learned from AD show that translational immunology allows generating rational therapies for AD and learning its immunopathogenesis in the patient.
Learn More >Cluster headache (CH) is a rare, primary headache disorder, characterized of excruciating, strictly one-sided pain attacks and ipsilateral cranial autonomic symptoms. Given the debilitating nature of CH, delayed diagnosis can increase the disease burden. Thus, we aimed to investigate the diagnostic delay, its predictors, and clinical influence among patients with CH.
Learn More >Migraine is a common headache disorder. Many studies have used magnetic resonance imaging (MRI) to explore the possible pathogenesis of migraine, but they have not reached consistent conclusions and lack rigorous multiple comparison correction. Thus, this study investigates the mechanisms of migraine development from the perspective of altered functional connectivity (FC) in brain regions by using data-driven and regions of interest (ROI)-based approaches.
Learn More >Neuropathic pain (NP) is defined as constant disabling pain secondary to a lesion or disease of the somatosensory nervous system. This condition is particularly difficult to treat because it often remains resistant to most treatment strategies. Despite the recent diversification of neurostimulation methods, some patients still suffer from refractory pain syndromes. The central role of the posterior insular cortex (PI) in the modulation of pain signaling and perception has been repeatedly suggested. The objective of this study is to assess whether epidural insular stimulation (IS) could reverse NP behavior.
Learn More >Pain after resolution of peripheral nerve block, known as 'rebound pain' (RP), is a major problem in outpatient surgery. The primary objective was to evaluate the benefit of intraoperative ketamine at an anti-hyperalgesic dose on the incidence of rebound pain after upper limb surgery under axillary plexus block in ambulatory patients. The secondary objective was to better understand the rebound pain phenomenon (individual risk factors).
Learn More >Headache, both before and after injury, has been associated with worse outcome following mild traumatic brain injury (MTBI). This study examined whether three MTBI patient groups – no headache (reported no pre-/post-injury headache), pre-injury headache (reported pre-injury headache, nearly all of whom also reported post-injury headache), and post-traumatic headache only (denied pre-injury headache and reported post-injury headache) – differed in acute-to-subacute outcomes.
Learn More >Lysophosphatidic acid (LPA) exerts various biological activities through six characterized G protein-coupled receptors (LPA ). While LPA-LPA signaling contributes toward the demyelination and retraction of C-fiber and induces neuropathic pain, the effects of LPA-LPA signaling on acute nociceptive pain is uncertain. This study investigated the role of LPA-LPA signaling in acute nociceptive pain using the formalin test. The pharmacological inhibition of the LPA-LPA axis significantly attenuated formalin-induced nociceptive behavior. The LPA mRNA was expressed in satellite glial cells (SGCs) in dorsal root ganglion (DRG) and was particularly abundant in SGCs surrounding large DRG neurons, which express neurofilament 200. Treatment with LPA receptor (LPA ) antagonist inhibited the upregulation of glial markers and inflammatory cytokines in DRG following formalin injection. The LPA antagonist also attenuated phosphorylation of extracellular signal-regulated kinase, especially in SGCs and cyclic AMP response element-binding protein in the dorsal horn following formalin injection. LPA amounts after formalin injection to the footpad were quantified by liquid chromatography/tandem mass spectrometry, and LPA levels were found to be increased in the innervated DRGs. Our results indicate that LPA produced in the innervated DRGs promotes the activation of SGCs through LPA , increases the sensitivity of primary neurons, and modulates pain behavior. These results facilitate our understanding of the pathology of acute nociceptive pain and demonstrate the possibility of the LPA on SGCs as a novel target for acute pain control.
Learn More >Pain-acute, chronic and debilitating-is the most feared neurotoxicity resulting from a survivable venomous snake bite. The purpose of this review is to present in a novel paradigm what we know about the molecular mechanisms responsible for pain after envenomation. Progressing from known pain modulating peptides and enzymes, to tissue level interactions with venom resulting in pain, to organ system level pain syndromes, to geographical level distribution of pain syndromes, the present work demonstrates that understanding the mechanisms responsible for pain is dependent on "location, location, location". It is our hope that this work can serve to inspire the molecular and epidemiologic investigations needed to better understand the neurotoxic mechanisms responsible for these snake venom mediated diverse pain syndromes and ultimately lead to agent specific treatments beyond anti-venom alone.
Learn More >Chronic diseases, as stated by the WHO, are a threat to human health which kill 3 out of every 5 people worldwide. Therapeutics for such illnesses can be developed using traditional medicine. However, it is not an easy path from natural products to Western pharmacological and pharmaceutical methods. For several decades, chronic inflammatory disorders, especially in Westernized countries, have increased incidence and prevalence. Several NSAIDs are used to decrease inflammation and pain; however, there are numerous negative consequences of these anti-inflammatory medications, whereas plant-based natural products have anti-inflammatory therapeutic benefits that have little or no adverse effects. Nanoparticles are a new type of drug delivery device that may be designed to provide excellent target selectivity for certain cells and tissues while also having a high drug loading capacity, resulting in better pharmacokinetics, pharmacodynamics (PKPD), and therapeutic bioavailability. The size and polarity of phytochemical compounds make it hard to pass the blood-brain barrier (BBB), blood-vessel endothelial lining, gastrointestinal tract and mucosa. In addition, the gastrointestinal system is enzymatically destroyed. Therefore, nanoparticles or nanocrystals might also be used for encapsulation or conjugation of these chemicals as a method to improve their organic effectiveness through their gastrointestinal stability, absorption rate and dispersion. The therapy of numerous inflammatory illnesses, including arthritis, gastritis, Nephritis, Hepatitis (Type A, B &C), ulcerative colitis, Alzheimer's disease, atherosclerosis, allergic responses (asthma, eczema) or autoimmune disorders, is characterised by nanoparticles. This review paper provides information on the numerous nanosystem described with their probable mechanism to treat chronic inflammatory diseases.
Learn More >Chronic pelvic pain (CPP) affects a significant proportion of women worldwide And has a negative impact on several aspects of these women's lives including mental health, work, relationships and sexual function, among others. This set of factors ultimately reflects negatively on quality Of life. The physiopathology of CPP is complex and remains to be fully clarified; however, recent advances have increased understanding of the mechanisms involved in chronic pain in general, and more specifically, CPP. Nonetheless, even when a detailed clinical history is obtained, meticulous physical examination is performed and imaging resources are appropriately used, the organic cause of the pain may still fail to be identified in a substantial number of women with CPP. Management of CPP may therefore be challenging. This narrative review was aimed at adding to the available literature on the subject, presenting and discussing the principal characteristics of CPP in women. The paper highlights gaps in the literature while providing the most up-to-date evidence associated with the physiopathology and classification of pain, its diagnosis and treatment. In addition, current challenges in the management of women with CPP are discussed.
Learn More >Peripheral nerve injury involves divergent alterations within dorsal root ganglia (DRG) neurons sensitized by persistent inflammation. Thymic stromal lymphopoietin (TSLP) production is crucial in the development of chronic inflammatory responses. Herein, we investigate the changes of TSLP expression in rats' DRG neurons between injured and uninjured sides in the same rat. Linalyl acetate (LA) was served as a TSLP inhibitor and given intraperitoneally. Rats were assigned to be group of chronic constriction injury (CCI) of the sciatic nerve and the group of CCI of the sciatic nerve administrated with LA. Over 14 days, the rats were measured for paw withdrawal thresholds. DRGs were collected to assess morphological changes via immunofluorescence study. After receiving CCI, the rats rapidly developed mechanical hyperalgesia. TSLP expression at DRG, on the ipsilateral injured side, was consistent with changes in pain behaviors. TSLP appeared in nerve fibers with both small diameters and large diameters. Additionally, TSLP was expressed mostly in transient receptor potential vanilloid-1 (TRPV1)-positive nociceptive neurons. Administration with LA can attenuate the pain behaviors and expression of TSLP in DRG neurons, and in apoptotic neurons at the injured side, but not in the contra-lateral uninjured side. Overall, these results imply that altered expressions of TSLP in nociceptive DRG neurons contributed to mechanical hyperalgesia in a CCI rat model.
Learn More >Irritable bowel syndrome (IBS) is a common gastrointestinal tract disorder, affecting 10-20% of adults worldwide. Mebeverine is an antispasmodic agent indicated for the symptomatic treatment of abdominal pain caused by intestinal smooth muscle spasms and intestinal functional disorders in the course of IBS. The aim of this article was to perform a systematic literature review and update previous overviews of the efficacy and safety of mebeverine treatment in IBS.
Learn More >Juvenile fibromyalgia (JFM) is a condition that presents as chronic widespread musculoskeletal pain and affects children and adolescents. JFM remains a challenging diagnosis, as it is both based on subjective criteria and the pathogenesis is poorly understood. Small fiber neuropathy (SFN) is a distinct condition, which is characterized by pathology of small A-delta and C fibers, and can present similarly to JFM. Small fiber pathology is characterized by reduced intraepidermal nerve fiber density (IENFD) on skin biopsy. Recent studies have found that as many as half of patients with JFM can demonstrate decreased IENFD, in pattern similar to SFN. This phenomenon has been referred to as small fiber pathology. The meaning of these findings was disputed; however, the current consensus remains that fibromyalgia and SFN are distinct conditions. Additionally, among patients with fibromyalgia, there are two phenotypes: those with small fiber pathology and those without. The purpose of this review was to characterize the role assessment of IENFD plays in the clinical context. We conducted a narrative review of pertinent articles pertaining to JFM, SFN and small fiber pathology in fibromyalgia. We concluded that assessment of IENFD should be completed if SFN is suspected either when a patient first presents or in patients who were previously diagnosed with fibromyalgia and SFN is later suspected. Distinguishing between JFM and SFN is important because recommended therapies differ between the two conditions. However, there is no evidence to support the use of skin biopsy to distinguish between the two discussed fibromyalgia phenotypes. More studies are needed to elucidate whether IENFD varies with morbidity and if both fibromyalgia phenotypes vary in their response to different therapeutic regimens.
Learn More >Music intervention (MI) has been applied as an effective adjunctive treatment for pain control in various clinical settings. However, no meta-analysis has yet been published on the analgesic effects of MI in infants and children. We performed a systematic review of PubMed, EMBASE, Web of Science, and Cochrane Library databases to identify randomized controlled trials (RCTs) with the keywords "pain" AND "music therapy" from inception to January 2022. Primary outcomes were pain intensity and vital signs. Standardized mean difference (SMD) values and the corresponding 95% confidence intervals (CIs) were computed using a random effect model. Subgroup analyses with age groups, types of pain, and music styles were conducted. A total of 38 RCTs involving 5601 participants met the selection criteria. MI significantly decreased the pain levels (SMD = -0.57, < 0.001), both in the newborn group ( = 0.007) and in the infant/children group ( < 0.001). MI significantly reduced heart rate (SMD = -0.50, < 0.001) and respiratory rate (SMD = -0.60, = 0.002) and increased peripheral capillary oxygen saturation (SMD = 0.44, < 0.001). In subgroup analyses of types of pain, MI had significant effects on prick pain ( = 0.003), chronic and procedural pain ( < 0.001), and postoperative pain ( = 0.018). As for music styles, significant analgesic effects were observed for classical music ( < 0.001), kids' music ( < 0.001), and pop music ( = 0.001), but not for world music ( = 0.196), special composition ( = 0.092), and multiple music combinations ( = 0.420). In conclusion, our analysis provides supportive evidence about the efficacy of MI, especially classical, kids', and pop music, in controlling prick, procedural, and postoperative pain in the pediatric population.
Learn More >Humans have used opioids to suppress moderate to severe pain for thousands of years. However, the long-term use of opioids has several adverse effects, such as opioid tolerance, opioid-induced hyperalgesia, and addiction. In addition, the low efficiency of opioids in controlling neuropathic pain limits their clinical applications. Combining nonopioid analgesics with opioids to target multiple sites along the nociceptive pathway may alleviate the side effects of opioids. This study reviews the feasibility of reducing opioid side effects by regulating the transient receptor potential vanilloid 1 (TRPV1) receptors and summarizes the possible underlying mechanisms. Blocking and activating TRPV1 receptors can improve the therapeutic profile of opioids in different manners. TRPV1 and μ-opioid receptors are bidirectionally regulated by β-arrestin2. Thus, drug combinations or developing dual-acting drugs simultaneously targeting μ-opioid and TRPV1 receptors may mitigate opioid tolerance and opioid-induced hyperalgesia. In addition, TRPV1 receptors, especially expressed in the dorsal striatum and nucleus accumbens, participate in mediating opioid reward, and its regulation can reduce the risk of opioid-induced addiction. Finally, co-administration of TRPV1 antagonists and opioids in the primary action sites of the periphery can significantly relieve neuropathic pain. In general, the regulation of TRPV1 may potentially ameliorate the side effects of opioids and enhance their analgesic efficacy in neuropathic pain.
Learn More >As the nervous system develops, nerve fibers from the brain form descending tracts that regulate the execution of motor behavior within the spinal cord, incoming sensory signals, and capacity to change (plasticity). How these fibers affect function depends upon the transmitter released, the receptor system engaged, and the pattern of neural innervation. The current review focuses upon the neurotransmitter serotonin (5-HT) and its capacity to dampen (inhibit) neural excitation. A brief review of key anatomical details, receptor types, and pharmacology is provided. The paper then considers how damage to descending serotonergic fibers contributes to pathophysiology after spinal cord injury (SCI). The loss of serotonergic fibers removes an inhibitory brake that enables plasticity and neural excitation. In this state, noxious stimulation can induce a form of over-excitation that sensitizes pain (nociceptive) circuits, a modification that can contribute to the development of chronic pain. Over time, the loss of serotonergic fibers allows prolonged motor drive (spasticity) to develop and removes a regulatory brake on autonomic function, which enables bouts of unregulated sympathetic activity (autonomic dysreflexia). Recent research has shown that the loss of descending serotonergic activity is accompanied by a shift in how the neurotransmitter GABA affects neural activity, reducing its inhibitory effect. Treatments that target the loss of inhibition could have therapeutic benefit.
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