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Opioid analgesic misuse by patients with chronic non-cancer pain is increasing in Western countries. To determine the extent of opioid misuse by patients with chronic non-cancer pain followed at a French pain management clinic. A questionnaire on pain (severity, causes and management) and opioid misuse (based on the 11 DSM-V criteria for substance abuse disorders) was administered by a health professional to patients during a short hospitalization. During the study period (September 1, 2015 to March 31, 2016), 52 patients (73.1% women; median age = 50 years [IQR: 43-57]) responded to the questionnaire. Chronic pain was caused by fibromyalgia in 55.6% of patients, and was mainly classified as neurogenic (32.6%), nociceptive (30.4%), and psychosomatic (15.2%). At hospitalization, the median pain visual analog scale score was 7/10 [IQR: 6-8], despite the ongoing treatment. The opioid misuse evaluation suggested the presence of misuse in 76.9% of patients (≥2 DSM-V criteria) that was severe in 52% of patients (≥6 DSM-V criteria). Our data highlight the high prevalence of misuse of prescribed opioids by adults with chronic non-cancer pain. A consultation with an addiction specialist should be included in the management of such patients.
Learn More >Neck pain is common in migraine and tension type headache (TTH). This review aimed to examine the evidence for cervical musculoskeletal impairments in these headaches.
Learn More >Neuropathic pain is a type of chronic pain induced by either central or peripheral nerve injury. MicroRNAs (miRs) have been recently linked to many diseases, including neuropathic pain. However, the role of miR-7a in neuropathic pain still remains elusive. Thus, we aim to investigate the effects of miR-7a on neuropathic pain based on the spinal nerve ligation (SNL) rat model. After establishment of SNL rat models, rats were infected with adeno associated virus (AAV)-neurofilament light polypeptide (NEFL), AAV-miR-7a or treated with metformin. The paw withdrawal threshold (PWT) and paw withdrawal latency (PWL) were assessed afterward, and the expression of miR-7a and NEFL as well as their interaction was determined. Subsequently, miR-7a was overexpressed or silenced in dorsal root ganglion (DRG) cells to investigate the role of miR-7a in neuropathic pain. Furthermore, the regulatory effect of NEFL on neuropathic pain was detected using plasmid overexpressing NEFL. SNL rat model exhibited upregulation of NEFL but downregulation of miR-7a. Additionally, NEFL accumulation or miR-7a inhibition decreased PWT and PWL. Then, NEFL accumulation or miR-7a inhibition was observed to increase the phosphorylation level of STAT3. miR-7a was found to directly target NEFL and downregulate NEFL. In addition, inhibiting the STAT3 signaling pathway was also revealed to increase PWT and PWL. Collectively, our study demonstrated that miR-7a ameliorated neuropathic pain via blocking the STAT3 signaling pathway by repressing NEFL. These findings, if taken further, can be of important clinical significance in treating patients with neuropathic pain.
Learn More >Occupational exposure to mechanical vibration can produce the Hand-Arm Vibration Syndrome (HAVS), whose most disabling symptom is persistent muscle pain. Unfortunately, the pathophysiology of HAVS pain is still poorly understood, precluding the development of mechanism-based therapies. Since interleukin 33 (IL-33) is essential for inflammation and recovery that follows skeletal muscle injury, we explored its role in muscle pain in a model of HAVS, in adult male rats. Concomitant to mechanical hyperalgesia, an increase in IL-33 in the ipsilateral gastrocnemius muscle was observed 24 h after vibration. A similar hyperalgesia was produced by intramuscular injection of recombinant rat IL-33 (rrIL-33, 10-300 ng). Intrathecal administration of an oligodeoxynucleotide antisense to IL-33R/ST2 mRNA decreased the expression of ST2 in DRG and attenuated both rrIL-33 and vibration-induced mechanical hyperalgesia. Together these data support the suggestion that IL-33 plays a central role in vibration-induced muscle pain by action, at least in part, on skeletal muscle nociceptors. PERSPECTIVE: Our findings provide evidence of the contribution of IL-33, acting on its canonical receptor, in nociceptors, to muscle pain induced by ergonomic vibration. This suggests that targeting IL-33/ST2 signaling may be a useful strategy for the treatment of muscle pain in hand-arm vibration syndrome.
Learn More >Targeting individually based psychosocial profiles when treating children with chronic pain and their families is key to effective behavioral health intervention and in line with tenants of precision medicine. Extant research is primarily driven by variable-centered models that focus on broad, group-level differences. The current study adopts a person-centered approach, latent profile analysis (LPA), to identify patient subgroups. Cross-sectional data are presented from 366 children (8-17 years; M=14.48; SD=2.36) with chronic pain and a primary caregiver (94% mothers). LPA indicator variables were, self-reported: fatigue, internalizing symptoms, pain catastrophizing, and pain acceptance; parent-reported: pain catastrophizing and responses to child pain. One-way ANOVAs examined the effect of profiles on child age, pain, and function. LPA identified a four-profile solution. Class 1 (12%) demonstrated the lowest scores (conveying least risk) across 5 of 6 factors. Class 4 (37%) had the highest scores (conveying greatest risk) across all factors. Classes 2 (12%) and 3 (39%) demonstrated more variability across domains. Results revealed significant effects of profile based on child age, pain, and function. This study highlights differential presentation of treatment-modifiable domains within a large sample. LPA methodology is showcased to potentially facilitate clinical conceptualizations and tailored approaches to intervention in pediatric chronic pain. Perspective: This article presents a methodological and statistical approach that may be beneficial to better assess individual profiles of pediatric pain functioning. Tools that allow providers to better match patient presentation and intervention are in line with the tenants of precision medicine and may ultimately serve to improve child outcomes.
Learn More >Management of bone cancer pain (BCP) is difficult because of its complex mechanisms, which has a major impact on the quality of patients' daily life. Recent studies have indicated that endoplasmic reticulum (ER) stress is involved in many neurological and inflammatory pathways associated with pain. However, the factors that contribute to ER stress and its causes in bone cancer pain are still unknown. In this study, we examined whether the ER stress response is involved in caspase signaling pathway-dependent apoptosis in neurons in the spinal dorsal horn of tumor-38 bearing rats and whether it thereby induces bone cancer pain.
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