Pain
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Animal models suggest that chemokines are important mediators in the pathophysiology of neuropathic pain. Indeed, these substances have been called "gliotransmitters," a term that illustrates the close interplay between glial cells and neurons in the context of neuroinflammation and pain. However, evidence in humans is scarce. ⋯ These 6 proteins were also major results in a recent similar study in patients with fibromyalgia. The findings need to be confirmed in larger cohorts, and the question of causality remains to be settled. Because it has been suggested that prevalent comorbidities to chronic pain (eg, depression, anxiety, poor sleep, and tiredness) also are associated with neuroinflammation, it will be important to determine whether neuroinflammation is a common mediator.
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Randomized Controlled Trial
Emotional awareness and expression therapy, cognitive-behavioral therapy, and education for fibromyalgia: a cluster-randomized controlled trial.
Patients with fibromyalgia (FM) experience increased lifetime levels of psychosocial adversity, trauma, and emotional conflict. To address these risk factors, we developed emotion awareness and expression therapy (EAET) and tested its benefits against an active control condition, FM education, and the field's gold standard intervention for FM, cognitive behavioral therapy (CBT) for symptom management. Adults with FM (N = 230) formed 40 treatment groups, which were randomized to EAET, CBT, or education and given 8, 90-minute sessions. ⋯ Emotional awareness and expression therapy did not differ from CBT on the primary or most secondary outcomes, but compared to CBT, EAET led to significantly lower FM symptoms (d = 0.35) and widespread pain (d = 0.37) and a higher percentage of patients achieving 50% pain reduction (22.5% vs 8.3%). In summary, an intervention targeting emotional awareness and expression related to psychosocial adversity and conflict was well received, more effective than a basic educational intervention, and had some advantages over CBT on pain. We conclude that EAET should be considered as an additional treatment option for FM.
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Primary C-fiber nociceptors are broadly divided into peptidergic and nonpeptidergic afferents. TRPV1 is a thermosensitive cation channel mainly localized in peptidergic nociceptors, whereas MrgD is a sensory G protein-coupled receptor expressed in most nonpeptidergic nociceptive afferents. TRPV1 and MrgD fibers have been reported to be primarily involved in thermal and mechanical nociception, respectively. ⋯ Of interest, in a conditioned place avoidance assay, blue light induced aversion in TRPV1-ChR2 mice, but not in MrgD-ChR2 mice. In short, we present novel somatosensory transgenic models in which control of specific subsets of peripheral unmyelinated nociceptors with distinct functions can be achieved with high spatiotemporal precision. These new tools will be instrumental in further clarifying the contribution of genetically identified C-fiber subtypes to chronic pain.