Pain
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The dysfunctional chronic pain (Dysfunctional CP) phenotype is an empirically identifiable CP subtype with unclear pathophysiological mechanisms that cuts across specific medical CP diagnoses. This study tested whether the multidimensional pain and psychosocial features that characterize the dysfunctional CP phenotype are associated broadly with elevated oxidative stress (OS). Measures of pain intensity, bodily extent of pain, catastrophizing cognitions, depression, anxiety, sleep disturbance, pain interference, and function were completed by 84 patients with chronic osteoarthritis before undergoing total knee arthroplasty. ⋯ OS measures were not significantly associated with sleep disturbance or anxiety levels (P >0.10). The results build on prior case-control findings suggesting that presence of a CP diagnosis is associated with elevated OS, highlighting that it may specifically be individuals displaying characteristics of the dysfunctional CP phenotype who are characterized by elevated OS. Clinical implications of these findings remain to be determined.
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Group I metabotropic glutamate receptors (group I mGluRs) have been implicated in several central nervous system diseases including chronic pain. It is known that activation of group I mGluRs results in the production of inositol triphosphate (IP3) and diacylglycerol that leads to activation of extracellular signal-regulated kinases (ERKs) and an increase in neuronal excitability, but how group I mGluRs mediate this process remains unclear. We previously reported that Orai1 is responsible for store-operated calcium entry and plays a key role in central sensitization. ⋯ Dihydroxyphenylglycine-induced activation of ERKs and modulation of neuronal excitability are abolished in cultured Orai1-deficient neurons. Moreover, DHPG-induced nociceptive behavior is markedly reduced in Orai1-deficient mice. Our findings reveal previously unknown functional coupling between Orai1 and group I mGluRs and shed light on the mechanism underlying group I mGluRs-mediated neuronal plasticity.
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Yoga is frequently used for back pain relief. However, the evidence was judged to be of only low to moderate certainty. To assess the efficacy and safety of yoga in patients with low back pain, a meta-analysis was performed. ⋯ Compared with passive control, yoga was associated with short-term improvements in pain intensity (15 RCTs; mean difference [MD] = -0.74 points on a numeric rating scale; 95% confidence interval [CI] = -1.04 to -0.44; standardized mean difference [SMD] = -0.37 95% CI = -0.52 to -0.22), pain-related disability (15 RCTs; MD = -2.28; 95% CI = -3.30 to -1.26; SMD = -0.38 95% CI = -0.55 to -0.21), mental health (7 RCTs; MD = 1.70; 95% CI = 0.20-3.20; SMD = 0.17 95% CI = 0.02-0.32), and physical functioning (9 RCTs; MD = 2.80; 95% CI = 1.00-4.70; SMD = 0.28 95% CI = 0.10-0.47). Except for mental health, all effects were sustained long-term. Compared with an active comparator, yoga was not associated with any significant differences in short-term or long-term outcomes.