Pain
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Case Reports
Heme and sensory neuropathy: insights from novel mutations in the heme exporter FLVCR1.
Hereditary sensory and autonomic neuropathies (HSANs) are a group of clinically and genetically heterogeneous disorders of the peripheral nervous system mainly characterized by impaired nociception and autonomic dysfunction. We previously identified heme metabolism as a novel pathway contributing to sensory neurons maintenance and nociception. Indeed, we reported mutations in the feline leukemia virus subgroup C receptor 1 (FLVCR1) gene in individuals affected by HSAN. ⋯ The impact of different kinds of mutations on FLVCR1a localization and structure was also described. The identification of novel FLVCR1 mutations in HSAN reinforces the crucial role of heme in sensory neuron maintenance and pain perception. Moreover, our in vitro findings demonstrate that heme export is not completely lost in HSAN patients, thus suggesting the possibility to improve FLVCR1 expression/activity for therapeutic purposes.
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Pain catastrophizing has been shown to predict greater pain and less physical function in daily life for chronic pain sufferers, but its effects on close social partners have received much less attention. The overall purpose of this study was to examine the extent to which pain catastrophizing is an interpersonal coping strategy that is maladaptive for patients and their spouses. A total of 144 older knee osteoarthritis patients and their spouses completed baseline interviews and a 22-day diary assessment. ⋯ Multilevel mediation models showed that patients' morning pain catastrophizing indirectly impacted spouses' negative affect and punishing responses through patients' own greater negative affect throughout the day. There was no evidence that spouses' empathic or solicitous responses either followed or preceded patients' catastrophizing. These findings suggest that cognitive-behavioral interventions that reduce pain catastrophizing should be modified for partnered patients to address dyadic interactions and the spouse's role in pain catastrophizing.
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While the contribution of social processes to pain perception is well documented, surprisingly little is known about the influence of pain on social perception. In particular, an important question is how pain modulates the processing of other people's actions. To address this question, the current study tests, using automatic imitation, the hypothesis that pain interferes with motor simulation-that is, the processing of observed actions in the motor system. ⋯ Automatic imitation was measured in a pain-free context, a context where pain was coupled to the execution of a movement (experiment 1), and a context where pain occurred randomly (experiment 2). The results revealed that automatic imitation, indexed by slower responses on incongruent compared with congruent trials, was reduced when experiencing pain, both when pain was linked to movement execution and when it was not. Thus, the current study shows that pain leads to reduced motor processing of others' behavior and, as such, has important implications for understanding the social difficulties associated with pain.
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About half of patients with spinal cord injury (SCI) develop debilitating central neuropathic pain (CNP), with no effective treatments. Thus, effective, safe, and novel therapies are needed urgently. Previously, docosahexaenoic acid (DHA) was reported to confer neuroprotection in preclinical SCI models. ⋯ Spinal microgliosis, a known hallmark associated with neuropathic pain behaviours, was reduced by DHA treatments. Finally, we revealed novel potential roles of peroxisome proliferator-activated and retinoid X receptors and docosahexaenoyl ethanolamide (DHA's metabolite) in mediating DHA's effects on microglial activation. Our findings, coupled with the excellent long-term clinical safety of DHA even in surgical and critically ill patients, suggest that systemic DHA treatment is a translatable, effective, safe, and novel approach for preventing and managing SCI-CNP.