Location-specific responses to nociceptive input support the purposeful nature of motor adaptation to pain
This study addressed this question using high-density electromyography (EMG) to study regional redistribution of muscle activation within the vasti muscles and changes in knee extension force direction in response to noxious stimulation applied to muscular and nonmuscular tissues around the knee. Fourteen participants performed a low-force knee extension contraction at baseline, during, and after pain induced in 4 locations (infrapatellar fat pad, vastus lateralis, distal vastus medialis, or proximal vastus medialis). The knee extension force direction was estimated from a 3-dimensional load cell positioned just above the ...
Source: Pain - October 25, 2018 Category: Anesthesiology Tags: Research Paper Source Type: research

Influence of neuropathic pain on nicotinic acetylcholine receptor plasticity and behavioral responses to nicotine in rats
Tobacco smoking is particularly evident in individuals experiencing chronic pain. This complex relationship is poorly understood at both molecular and behavioral levels. Here, we describe experiments aimed at understanding whether a chronic pain state induces neuroadaptations into the brain or peripheral nerves that involve nicotinic acetylcholine receptors (nAChRs) and whether these neuroadaptations directly lead to increased vulnerability to nicotine addiction or to the development of coping strategies to relieve pain symptoms. We found that ligation of the rat L5 spinal nerve led to a dramatic downregulation in the mRNA...
Source: Pain - October 25, 2018 Category: Anesthesiology Tags: Research Paper Source Type: research

Involvement of lysophosphatidic acid–induced astrocyte activation underlying the maintenance of partial sciatic nerve injury–induced neuropathic pain
We have previously demonstrated that lysophosphatidic acid (LPA) plays key roles in the initial mechanisms for neuropathic pain (NeuP) development. Here, we examined whether LPA receptor mechanisms and LPA production are related to the glial activation at a late stage after partial sciatic nerve ligation (pSNL) by use of microglial inhibitor, Mac1-saporin or astrocyte inhibitor, and L-α-aminoadipate (L-AA). Although single intrathecal injection of LPA1/3 antagonist, Ki-16425 did not affect the pain threshold at day 7 after the spinal cord injury, repeated treatments of each compound gradually reversed the basal pain ...
Source: Pain - October 25, 2018 Category: Anesthesiology Tags: Research Paper Source Type: research

Do post-traumatic pain and post-traumatic stress symptomatology mutually maintain each other? A systematic review of cross-lagged studies
In conclusion, the findings suggest an entangled, but not necessarily mutually maintaining relationship between pain and PTSD symptomatology. However, major variations in findings and methodologies complicated synthesis, prompting careful interpretation and heightening the likelihood that future high-quality studies will change these conclusions. (Source: Pain)
Source: Pain - October 25, 2018 Category: Anesthesiology Tags: Systematic Review and Meta-Analysis Source Type: research

Twenty-five years of pain education research—what have we learned? Findings from a comprehensive scoping review of research into pre-registration pain education for health professionals
This article reports on a synthesis of pain education research that has been conducted in this period of health professionals' training. A scoping review framework by Arksey and O'Malley was used to guide a search of medical and education databases for records that have examined or evaluated pain education. Fifty-six reports were identified representing 16 professions across 29 countries, published between 1992 and 2017. A descriptive account of the reports is provided, which includes a timeline, geography, methods of evaluating, and main purpose of the research. A narrative synthesis was undertaken to summarise and explai...
Source: Pain - October 25, 2018 Category: Anesthesiology Tags: Narrative Review Source Type: research

Depression in chronic pain: might opioids be responsible?
No abstract available (Source: Pain)
Source: Pain - October 25, 2018 Category: Anesthesiology Tags: Topical Review Source Type: research

Conceptual complexity of gender and its relevance to pain
No abstract available (Source: Pain)
Source: Pain - October 25, 2018 Category: Anesthesiology Tags: Topical Review Source Type: research

What do clinicians consider when assessing chronic low back pain? A content analysis of multidisciplinary pain centre team assessments of functioning, disability, and health
This study sought to map the content of MPC clinical assessments to the ICF to: (1) identify and compare the content of clinical MDT assessments using a cross-disciplinary framework and (2) examine the content validity of the LBP-CS. A qualitative examination of MPC team clinical assessments of chronic low back pain was undertaken. Multidisciplinary team (pain medicine, psychiatry, nursing, physiotherapy, occupational therapy, and psychology) assessments were audio-recorded and transcribed. Concepts were extracted from transcripts using a meaning condensation procedure and then linked to the ICF. Across 7 MDT assessments, ...
Source: Pain - October 1, 2018 Category: Anesthesiology Tags: Clinical Note Source Type: research

Inhibition of the Ubc9 E2 SUMO-conjugating enzyme–CRMP2 interaction decreases NaV1.7 currents and reverses experimental neuropathic pain
We previously reported that destruction of the small ubiquitin-like modifier (SUMO) modification site in the axonal collapsin response mediator protein 2 (CRMP2) was sufficient to selectively decrease trafficking of the voltage-gated sodium channel NaV1.7 and reverse neuropathic pain. Here, we further interrogate the biophysical nature of the interaction between CRMP2 and the SUMOylation machinery, and test the hypothesis that a rationally designed CRMP2 SUMOylation motif (CSM) peptide can interrupt E2 SUMO-conjugating enzyme Ubc9-dependent modification of CRMP2 leading to a similar suppression of NaV1.7 currents. Microsca...
Source: Pain - October 1, 2018 Category: Anesthesiology Tags: Research Paper Source Type: research

Long-term pain relief in canine osteoarthritis by a single intra-articular injection of resiniferatoxin, a potent TRPV1 agonist
We report on a peripheral interventional approach that uses intra-articular injection of the ultrapotent TRPV1 agonist resiniferatoxin (RTX) to produce a selective long-term chemoinactivation of nociceptive primary afferent nerve endings for pain control in naturally occurring canine osteoarthritis. A single injection of 10 µg of RTX, produced suppression of pain, improvement in gait, weight bearing, and improvement in the dog's activities of daily living lasting 4 months or longer. Two to 3 years after the injection, there are no alterations to suggest that removal of inflammatory pain caused accelerated joint degen...
Source: Pain - October 1, 2018 Category: Anesthesiology Tags: Research Paper Source Type: research

Changes in pain intensity after discontinuation of long-term opioid therapy for chronic noncancer pain
The objective of this study was to characterize pain intensity after opioid discontinuation over 12 months. This retrospective U.S. Department of Veterans Affairs (VA) administrative data study identified N = 551 patients nationally who discontinued LTOT. Data over 24 months (12 months before and after discontinuation) were abstracted from VA administrative records. Random-effects regression analyses examined changes in 0 to 10 pain numeric rating scale scores over time, whereas growth mixture models delineated pain trajectory subgroups. Mean estimated pain at the time of opioid discontinuation was 4.9. Changes in pain aft...
Source: Pain - October 1, 2018 Category: Anesthesiology Tags: Research Paper Source Type: research

Patterns of recovery from pain after cesarean delivery
We know very little about the change in pain in the first 2 months after surgery. To address this gap, we studied 530 women scheduled for elective cesarean delivery who completed daily pain diaries for 2 months after surgery through text messaging. Over 82% of subjects missed fewer than 10 diary entries and were included in the analysis. Completers were more likely to be Caucasian, nonsmokers, and with fewer previous pregnancies than noncompleters. Daily worst pain intensity ratings for the previous 24 hours were fit to a log(time) function and allowed to change to a different function up to 3 times according to a Bayesian...
Source: Pain - October 1, 2018 Category: Anesthesiology Tags: Research Paper Source Type: research

Multivariate pattern classification of brain white matter connectivity predicts classic trigeminal neuralgia
This study demonstrates that machine-learning algorithms can detect characteristic patterns of structural alterations in TN and highlights the role of structural brain imaging for identification of neuroanatomical features associated with neuropathic pain disorders. (Source: Pain)
Source: Pain - October 1, 2018 Category: Anesthesiology Tags: Research Paper Source Type: research

Mixed-methods development of a new patient-reported outcome instrument for chronic low back pain: part 2—The Patient Assessment for Low Back Pain–Impacts (PAL-I)
We describe qualitative and quantitative development and preliminary validation of the Patient Assessment for Low Back Pain–Impacts (PAL-I), a patient-reported outcome measure for use in chronic low back pain (cLBP) clinical trials. Concept elicitation and cognitive interviews (qualitative methods) were used to identify and refine symptom concepts. Classical test theory and Rasch measurement theory (quantitative methods) were used to evaluate item-level and scale-level performance of the PAL-I using an iterative approach between qualitative and quantitative methods. Patients with cLBP participated in concept elicitat...
Source: Pain - October 1, 2018 Category: Anesthesiology Tags: Research Paper Source Type: research

Dynamic sodium imaging at ultra-high field reveals progression in a preclinical migraine model
Under the hypothesis that increased extracellular sodium induces sustained neuronal excitability with the onset and progression of migraine, this study evaluates dynamic in vivo 23Na fluxes in the brain of a preclinical rodent analogue of migraine. Ultra-high field 23Na magnetic resonance imaging (MRI) at 21.1 T has demonstrated potential to quantify sodium concentrations with good spatial and temporal resolution after the onset of central sensitization. Sprague-Dawley male rats with implanted intraperitoneal lines were studied by MRI before and after an in situ injection of 10 mg/kg of nitroglycerin (NTG) vs vehicle and s...
Source: Pain - October 1, 2018 Category: Anesthesiology Tags: Research Paper Source Type: research

Racial differences in opioid prescribing for children in the United States
We examined racial and ethnic differences in outpatient analgesic prescribing using nationally representative data from 113,929 children from the Medical Expenditure Panel Survey. We also examined whether patient–provider race and ethnic concordance was associated with opioid prescription. White children were more commonly prescribed opioids as compared to minorities (3.0% vs 0.9%-1.7%), except for Native American children who had similar rates of opioid prescription (2.6%) as white children. Minorities were more likely to receive nonopioid analgesics than white children (2.0%-5.7% vs 1.3%). Although most white child...
Source: Pain - October 1, 2018 Category: Anesthesiology Tags: Research Paper Source Type: research

Cultural influences on parental responses to children's pain
There is a scarcity of work examining the relationship between culture and pain-related caregiver behaviors. Moreover, no pediatric pain studies have examined the relationship between caregiver cultural values and pain-related caregiver behaviors nor discern if this process is mediated by caregiver parenting styles and moderated by ecosocial context. Based on cross-cultural developmental theories, this study hypothesized that ecosocial context would moderate the relationship between cultural values, parenting styles, and pain-related caregiver behaviors; and that parenting styles mediate the effect of cultural values on pa...
Source: Pain - October 1, 2018 Category: Anesthesiology Tags: Research Paper Source Type: research

Color-selective photophobia in ictal vs interictal migraineurs and in healthy controls
This study aimed at determining whether these findings are phase-dependent–namely, manifested exclusively during migraine (ictally) but not in its absence (interictally), or condition-dependent—ie, expressed uniquely in migraineurs but not in healthy controls. To determine whether the color preference of migraine-type photophobia is phase- or condition-dependent, we compared the effects of each color of light in each intensity between migraineurs during and in-between attacks and healthy controls. During the ictal and interictal phases, the proportion of migraineurs reporting changes in headache severity when e...
Source: Pain - October 1, 2018 Category: Anesthesiology Tags: Research Paper Source Type: research

Dermal nerve fibre and mast cell density, and proximity of mast cells to nerve fibres in the skin of patients with complex regional pain syndrome
An interaction between cutaneous nerves and mast cells may contribute to pain in complex regional pain syndrome (CRPS). To explore this, we investigated the density of dermal nerve fibres, and the density and proximity of mast cells to nerve fibres, in skin biopsies obtained from the affected and unaffected limbs of 57 patients with CRPS and 28 site-matched healthy controls. The percentage of the dermis stained by the pan-neuronal marker protein gene-product 9.5 was lower in the affected limb of patients than in controls (0.12 ± 0.01% vs 0.22 ± 0.04%, P (Source: Pain)
Source: Pain - October 1, 2018 Category: Anesthesiology Tags: Research Paper Source Type: research

Pain processing in the human brainstem and spinal cord before, during, and after the application of noxious heat stimuli
Descending regulation of spinal cord responses to nociceptive signaling has a strong influence on pain perception. Previous studies using functional magnetic resonance imaging (fMRI) have indicated that in addition to reactive responses to nociceptive signals, there is a continuous component to regulation, and that it may vary with differences in pain sensitivity. We hypothesize that this continuous regulation component occurs routinely in fMRI studies before noxious stimulation, as well as during, and after stimulation. This hypothesis was tested by analyzing data from 59 healthy participants in 4 previous fMRI studies in...
Source: Pain - October 1, 2018 Category: Anesthesiology Tags: Research Paper Source Type: research

Sensory sensitivity and symptom severity represent unique dimensions of chronic pain: a MAPP Research Network study
Chronic overlapping pain conditions (COPCs) are characterized by aberrant central nervous system processing of pain. This “centralized pain” phenotype has been described using a large and diverse set of symptom domains, including the spatial distribution of pain, pain intensity, fatigue, mood imbalances, cognitive dysfunction, altered somatic sensations, and hypersensitivity to external stimuli. Here, we used 3 cohorts, including patients with urologic chronic pelvic pain syndrome, a mixed pain cohort with other COPCs, and healthy individuals (total n = 1039) from the Multidisciplinary Approach to the Study of ...
Source: Pain - October 1, 2018 Category: Anesthesiology Tags: Research Paper Source Type: research

Psychophysical and vasomotor evidence for interdependency of TRPA1 and TRPV1-evoked nociceptive responses in human skin: an experimental study
The TRPA1 and TRPV1 receptors are important pharmaceutical targets for antipruritic and analgesic therapy. Obtaining further knowledge on their roles and interrelationship in humans is therefore crucial. Preclinical results are contradictory concerning coexpression and functional interdependency of TRPV1 and TRPA1, but no human evidence exists. This human experimental study investigated whether functional responses from the subpopulation of TRPA1+ nociceptors could be evoked after defunctionalization of TRPV1+ nociceptors by cutaneous application of high-concentration capsaicin. Two quadratic areas on each forearm were ran...
Source: Pain - October 1, 2018 Category: Anesthesiology Tags: Research Paper Source Type: research

Trigeminal ganglion transcriptome analysis in 2 rat models of medication-overuse headache reveals coherent and widespread induction of pronociceptive gene expression patterns
We report that both drug treatments change trigeminal ganglion gene expression to a similar extend. Of note, qualitative transcriptomic analysis shows that eletriptan and indomethacin prompt nearly identical, increased expression of genes coding for proteins involved in migraine pathogenesis and central pain sensitization such as neuropeptides, their cognate receptors, prostanoid, and nitric oxide–synthesizing enzymes, as well as TRP channels. These genes, however, were not affected in thoracic dorsal root ganglia. Of note, lowering of orofacial nociceptive thresholds, as well as forepaw hyperalgesia occurred in both...
Source: Pain - October 1, 2018 Category: Anesthesiology Tags: Research Paper Source Type: research

Pressure-induced referred pain areas are more expansive in individuals with a recovered fracture
This study compared the extent of pain referral in individuals recovered from a musculoskeletal trauma and healthy controls. Twenty pain-free participants recovered from a shoulder fracture and 20 age-/sex-matched controls participated in 2 experimental sessions (day-0 and day-1) separated by 24 hours. On both days, pressure pain thresholds were measured bilaterally at infraspinatus, supraspinatus, trapezius, and gastrocnemius muscles. Referred pain towards the shoulder region was induced by a 60-second pressure stimulation (pressure pain threshold + 20%) at the infraspinatus muscle and recorded on an electronic body chart...
Source: Pain - October 1, 2018 Category: Anesthesiology Tags: Research Paper Source Type: research

Should thoracic paravertebral blocks be used to prevent chronic postsurgical pain after breast cancer surgery? A systematic analysis of evidence in light of IMMPACT recommendations
The role of thoracic paravertebral block (PVB) in preventing chronic postsurgical pain (CPSP) after breast cancer surgery (BCS) has gained interest, but existing evidence is conflicting, and its methodological quality is unclear. This meta-analysis evaluates efficacy of PVB, compared with Control group, in preventing CPSP after BCS, in light of the Initiative on Methods, Measurement, and Pain Assessment in Clinical Trials (IMMPACT) recommendations. Electronic databases were searched for randomized trials comparing PVB with Control group for CPSP prevention after BCS. Eligible trials were assessed for adherence to IMMPACT r...
Source: Pain - October 1, 2018 Category: Anesthesiology Tags: Systematic Reviews and Meta-Analyses Source Type: research

Cannabis and cannabinoids for the treatment of people with chronic noncancer pain conditions: a systematic review and meta-analysis of controlled and observational studies
This review examines evidence for the effectiveness of cannabinoids in chronic noncancer pain (CNCP) and addresses gaps in the literature by: considering differences in outcomes based on cannabinoid type and specific CNCP condition; including all study designs; and following IMMPACT guidelines. MEDLINE, Embase, PsycINFO, CENTRAL, and clinicaltrials.gov were searched in July 2017. Analyses were conducted using Revman 5.3 and Stata 15.0. A total of 91 publications containing 104 studies were eligible (n = 9958 participants), including 47 randomised controlled trials (RCTs) and 57 observational studies. Forty-eight studies ex...
Source: Pain - October 1, 2018 Category: Anesthesiology Tags: Systematic Reviews and Meta-Analyses Source Type: research

Does the word “placebo” evoke a placebo response?
No abstract available (Source: Pain)
Source: Pain - October 1, 2018 Category: Anesthesiology Tags: Topical Review Source Type: research

Chronic pain in survivors of childhood cancer: a developmental model of pain across the cancer trajectory
No abstract available (Source: Pain)
Source: Pain - October 1, 2018 Category: Anesthesiology Tags: Topical Review Source Type: research

Targeting toll-like receptor-4 (TLR4)—an emerging therapeutic target for persistent pain states
Toll-like receptors (TLRs) are a family of pattern recognition receptors that initiate signaling in innate and adaptive immune pathways. The highly conserved family of transmembrane proteins comprises an extracellular domain that recognizes exogenous and endogenous danger molecules and an ectodomain that activates downstream pathways in response. Recent studies suggest that continuous activation or dysregulation of TLR signaling may contribute to chronic disease states. The receptor is located not only on inflammatory cells (meningeal and peripheral macrophages) but on neuraxial glia (microglia and astrocytes), Schwann cel...
Source: Pain - October 1, 2018 Category: Anesthesiology Tags: Comprehensive Review Source Type: research

Systematic reviews with meta-analysis on cannabis-based medicines for chronic pain: a methodological and political minefield
No abstract available (Source: Pain)
Source: Pain - October 1, 2018 Category: Anesthesiology Tags: Commentary Source Type: research

Responses to the sham treatment vs expectancy effects
No abstract available (Source: Pain)
Source: Pain - October 1, 2018 Category: Anesthesiology Tags: Commentary Source Type: research

Hyperpolarization-activated cyclic nucleotide–gated channels contribute to spontaneous activity in L4 C-fiber nociceptors, but not Aβ-non-nociceptors, after axotomy of L5-spinal nerve in the rat in vivo: Erratum.
No abstract available (Source: Pain)
Source: Pain - August 23, 2018 Category: Anesthesiology Tags: Erratum Source Type: research

Sensory phenotype and risk factors for painful diabetic neuropathy: a cross-sectional observational study Erratum.
No abstract available (Source: Pain)
Source: Pain - August 23, 2018 Category: Anesthesiology Tags: Erratum Source Type: research

“From ear to trunk”—magnetic resonance imaging reveals referral of pain
We present the case of a 69-year-old female patient with postherpetic neuralgia in dermatome Th2/3 who reported that touching the ipsilateral earlap (dermatome C2) would enhance pain and dynamic mechanical allodynia in the affected Th2/3-dermatome. The aim was to investigate possible underlying mechanisms of this phenomenon using the capsaicin experimental pain sensitization model, quantitative sensory testing, and functional spinal and supraspinal magnetic resonance imaging. The presented study provides evidence that a referral of pain from the ear to the trunk is possible. We discuss whether the observed phenomenon in co...
Source: Pain - August 23, 2018 Category: Anesthesiology Tags: Clinical Note Source Type: research

Selective deficiencies in descending inhibitory modulation in neuropathic rats: implications for enhancing noradrenergic tone
We examined the extent to which the descending noradrenergic system is tonically active, how control of spinal neuronal excitability is integrated into thalamic relays within sensory-discriminative projection pathways, and how this inhibitory control is altered after nerve injury. In vivo electrophysiology was performed in anaesthetised spinal nerve–ligated (SNL) and sham-operated rats to record from wide dynamic range neurones in the ventral posterolateral thalamus (VPL). In sham rats, spinal block of α2-adrenoceptors with atipamezole resulted in enhanced stimulus-evoked and spontaneous firing in the VPL, and ...
Source: Pain - August 23, 2018 Category: Anesthesiology Tags: Research Paper Source Type: research

Pain sensitization associated with nonresponse after physiotherapy in people with knee osteoarthritis
This study aimed to prospectively investigate the association between features of pain sensitization and clinical outcome (nonresponse) after guideline-based physiotherapy in people with knee OA. Participants (n = 156) with moderate/severe knee OA were recruited from secondary care. All participants completed self-administered questionnaires and underwent quantitative sensory testing at baseline, thereby establishing subjective and objective measures of pain sensitization. Participants (n = 134) were later classified after a physiotherapy intervention, using treatment responder criteria (responder/nonresponder). Quantitati...
Source: Pain - August 23, 2018 Category: Anesthesiology Tags: Research Paper Source Type: research

Sensory profiles and skin innervation of patients with painful and painless neuropathies
We assessed pain characteristics and sensory profiles of a large and extensively phenotyped cohort of patients with polyneuropathies (PNPs) and small fiber neuropathy (SFN) using quantitative sensory testing (QST). Our aim was to detect potentially discriminative QST profiles of patient subgroups determined by pain, etiology, or skin innervation. We prospectively recruited 350 patients with painful and painless PNPs and with SFN at 1 neuromuscular center. After neurological work-up, patients underwent QST at the dorsal foot and 5-mm skin punch biopsy at the lower leg and upper thigh for intraepidermal nerve fiber counts. A...
Source: Pain - August 23, 2018 Category: Anesthesiology Tags: Research Paper Source Type: research

Chronic neuropathic pain reduces opioid receptor availability with associated anhedonia in rat
The opioid system plays a critical role in both the experience and management of pain. Although acute activation of the opioid system can lead to pain relief, the effects of chronic pain on the opioid system remain opaque. Cross-sectional positron emission tomography (PET) studies show reduced availability of brain opioid receptors in patients with chronic pain but are unable to (1) determine whether these changes are due to the chronic pain itself or due to preexisting or medication-induced differences in the endogenous opioid system, and (2) identify the neurobiological substrate of reduced opioid receptor availability. ...
Source: Pain - August 23, 2018 Category: Anesthesiology Tags: Research Paper Source Type: research

Delayed onset of persistent discogenic axial and radiating pain after a single-level lumbar intervertebral disc injury in mice
Low back pain (LBP) is associated with both axial discomfort and radiating leg pain. Although intervertebral discs are suspected as the source of pain in some individuals, the relationship between disc degeneration and back pain remains controversial. The goals of this study were to investigate the long-term impact of L4/L5 disc puncture on disc degeneration and the subsequent emergence, persistence, and underlying mechanisms of axial and radiating LBP in mice. L4 to L5 discs were punctured on the ventral aspect with a 30 gauge needle in 3-month old female CD1 mice, and the development of behavioral signs of axial discomfo...
Source: Pain - August 23, 2018 Category: Anesthesiology Tags: Research Paper Source Type: research

Effects of internet-based pain coping skills training before home exercise for individuals with hip osteoarthritis (HOPE trial): a randomised controlled trial
This assessor-, therapist-, and participant-blinded randomised controlled trial evaluated the effects of an automated internet-based pain coping skills training (PCST) program before home exercise for people with clinically diagnosed hip osteoarthritis. One hundred forty-four people were randomised to either the PCST group or the comparator group. In the first 8 weeks, the PCST group received online education and PCST, whereas the comparison group received online education only. From weeks 8 to 24, both groups visited a physiotherapist 5 times for home exercise prescription. Assessments were performed at baseline, 8, 24, a...
Source: Pain - August 23, 2018 Category: Anesthesiology Tags: Research Paper Source Type: research

Hemisensory disturbances in patients with complex regional pain syndrome
Sensory disturbances often spread beyond the site of injury in complex regional pain syndrome (CRPS) but whether this applies equally to CRPS I and II, or changes across the course of the disease, is unknown. Establishing this is important, because different symptom profiles in CRPS I and II, or in acute vs chronic CRPS, might infer different pathophysiology and treatment approaches. To explore these questions, sensory disturbances were assessed in the limbs and forehead of 71 patients with CRPS I and 33 patients with CRPS II. Pain had persisted up to 12 months in 32 patients, for 13 to 36 months in 29 patients, and for lo...
Source: Pain - August 23, 2018 Category: Anesthesiology Tags: Research Paper Source Type: research

Peripherally restricted cannabinoid 1 receptor agonist as a novel analgesic in cancer-induced bone pain
Many malignant cancers, including breast cancer, have a propensity to invade bones, leading to excruciating bone pain. Opioids are the primary analgesics used to alleviate this cancer-induced bone pain (CIBP) but are associated with numerous severe side effects, including enhanced bone degradation, which significantly impairs patients' quality of life. By contrast, agonists activating only peripheral CB1 receptors (CB1Rs) have been shown to effectively alleviate multiple chronic pain conditions with limited side effects, yet no studies have evaluated their role(s) in CIBP. Here, we demonstrate for the first time that a per...
Source: Pain - August 23, 2018 Category: Anesthesiology Tags: Research Paper Source Type: research

Involvement of the VGF-derived peptide TLQP-62 in nerve injury–induced hypersensitivity and spinal neuroplasticity
Neuroplasticity in the dorsal horn after peripheral nerve damage contributes critically to the establishment of chronic pain. The neurosecretory protein VGF (nonacronymic) is rapidly and robustly upregulated after nerve injury, and therefore, peptides generated from it are positioned to serve as signals for peripheral damage. The goal of this project was to understand the spinal modulatory effects of the C-terminal VGF-derived peptide TLQP-62 at the cellular level and gain insight into the function of the peptide in the development of neuropathic pain. In a rodent model of neuropathic pain, we demonstrate that endogenous l...
Source: Pain - August 23, 2018 Category: Anesthesiology Tags: Research Paper Source Type: research

Efficacy of hypnosis on pain, wound-healing, anxiety, and stress in children with acute burn injuries: a randomized controlled trial
No randomized controlled trial has investigated the efficacy of hypnosis for reducing pain and improving wound-healing in children with burns. This randomized controlled trial aimed to investigate whether hypnosis decreases pain, anxiety, and stress and accelerates wound-healing in children undergoing burn wound procedures. Children (4-16 years) with acute burns presenting for their first dressing change were randomly assigned to a Hypnosis Group who received hypnosis plus standard care or a Standard Care Group who received standard pharmacological and nonpharmacological intervention. Repeated measures of pain intensity, a...
Source: Pain - August 23, 2018 Category: Anesthesiology Tags: Research Paper Source Type: research

Chronic stress-associated visceral hyperalgesia correlates with severity of intestinal barrier dysfunction
In humans, chronic psychological stress is associated with increased intestinal paracellular permeability and visceral hyperalgesia, which is recapitulated in the chronic intermittent water avoidance stress (WAS) rat model. However, it is unknown whether enhanced visceral pain and permeability are intrinsically linked and correlate. Treatment of rats with lubiprostone during WAS significantly reduced WAS-induced changes in intestinal epithelial paracellular permeability and visceral hyperalgesia in a subpopulation of rats. Lubiprostone also prevented WAS-induced decreases in the epithelial tight junction protein, occludin ...
Source: Pain - August 23, 2018 Category: Anesthesiology Tags: Research Paper Source Type: research

Multivariate machine learning distinguishes cross-network dynamic functional connectivity patterns in state and trait neuropathic pain
Communication within the brain is dynamic. Chronic pain can also be dynamic, with varying intensities experienced over time. Little is known of how brain dynamics are disrupted in chronic pain, or relates to patients' pain assessed at various timescales (eg, short-term state vs long-term trait). Patients experience pain “traits” indicative of their general condition, but also pain “states” that vary day to day. Here, we used network-based multivariate machine learning to determine how patterns in dynamic and static brain communication are related to different characteristics and timescales of chroni...
Source: Pain - August 23, 2018 Category: Anesthesiology Tags: Research Paper Source Type: research

Microglial P2X4R-evoked pain hypersensitivity is sexually dimorphic in rats
Microglia–neuron signalling in the spinal cord is a key mediator of mechanical allodynia caused by peripheral nerve injury. We recently reported sex differences in microglia in pain signalling in mice: spinal mechanisms underlying nerve injury–induced allodynia are microglial dependent in male but not female mice. Whether this sex difference in pain hypersensitivity mechanisms is conserved in other species is unknown. Here, we show that in rats, the spinal mechanisms of nerve injury–induced hypersensitivity in males differ from those in females, with microglial P2X4 receptors (P2X4Rs) being a key point of...
Source: Pain - August 23, 2018 Category: Anesthesiology Tags: Research Paper Source Type: research

A randomised, placebo-controlled clinical trial with the α2/3/5 subunit selective GABAA positive allosteric modulator PF-06372865 in patients with chronic low back pain
The effect of PF-06372865, a subtype-selective positive allosteric modulator of the γ-aminobutyric acid type A (GABAA) receptor, on chronic low back pain was investigated in a randomised, placebo- and active-controlled phase 2 clinical trial. The parallel treatment group trial consisted of a 1-week single-blind placebo run in the phase, followed by 4-week double-blind treatment. Patients were randomised to receive either PF-06372865, naproxen, or placebo twice a day for 4 weeks. The primary end point was the numerical rating score of low back pain intensity after 4 weeks of active treatment. Secondary end points incl...
Source: Pain - August 23, 2018 Category: Anesthesiology Tags: Research Paper Source Type: research

High-fat diet exacerbates postoperative pain and inflammation in a sex-dependent manner
In this study, effects of diet and obesity were examined in the paw incision model, a preclinical model of postoperative pain. Long–Evans rats were fed high-fat diet (40% calories from butter fat) or low-fat normal chow. Male rats fed high-fat diet starting 6 weeks before incision (a diet previously shown to induce markers of obesity) had prolonged mechanical hypersensitivity and an overall increase in spontaneous pain in response to paw incision, compared with normal chow controls. Diet effects in females were minor. Removing high-fat diet for 2 weeks before incision reversed the diet effects on pain behaviors, alth...
Source: Pain - August 23, 2018 Category: Anesthesiology Tags: Research Paper Source Type: research

NALCN channels enhance the intrinsic excitability of spinal projection neurons
Spinal projection neurons convey nociceptive signals to multiple brain regions including the parabrachial (PB) nucleus, which contributes to the emotional valence of pain perception. Despite the clear importance of projection neurons to pain processing, our understanding of the factors that shape their intrinsic membrane excitability remains limited. Here, we investigate a potential role for the Na+ leak channel NALCN in regulating the activity of spino-PB neurons in the developing rodent. Pharmacological reduction of NALCN current (INALCN), or the genetic deletion of NALCN channels, significantly reduced the intrinsic exc...
Source: Pain - August 23, 2018 Category: Anesthesiology Tags: Research Paper Source Type: research