Pain
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Alterations in the composition and function of the gut microbiome in women with fibromyalgia have recently been demonstrated, including changes in the relative abundance of certain bile acid-metabolizing bacteria. Bile acids can affect multiple physiological processes, including visceral pain, but have yet to be explored for association to the fibromyalgia gut microbiome. In this study, 16S rRNA sequencing and targeted metabolomic approaches were used to characterize the gut microbiome and circulating bile acids in a cohort of 42 women with fibromyalgia and 42 healthy controls. ⋯ The changes observed in the composition of the gut microbiota and the concentration of circulating secondary bile acids seem congruent with the phenotype of increased nociception and are quantitatively correlated with symptom severity. This is a first demonstration of circulating bile acid alteration in individuals with fibromyalgia, potentially secondary to upstream gut microbiome alterations. If corroborated in independent studies, these observations may allow for the development of molecular diagnostic aids for fibromyalgia as well as mechanistic insights into the syndrome.
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Multicenter Study
Exploring the trajectory curve of long-term musculoskeletal post-COVID pain symptoms in hospitalized COVID-19 survivors: a multicenter study.
This multicenter cohort study investigated the prevalence of musculoskeletal post-COVID pain during the first year after the infection with mosaic plots and an exponential bar plot model and its associated risk factors. Patients hospitalized because of COVID-19 in 5 hospitals of Madrid (Spain) were scheduled for a telephone interview at 2 follow-up periods after hospitalization for collecting data about musculoskeletal post-COVID pain. Hospitalization and clinical data were collected from hospital medical records. ⋯ Female sex (odds ratio [OR] 1.593, 95% confidence interval [CI] 1.148-2.211), history of musculoskeletal pain (OR 1.591, 95% CI 1.211-2.07), the presence of myalgia (OR 1.371, 95% CI 1.032-1.821) or headache (OR 2.278, 95% CI 1.622-3.199) at hospitalization, the days of hospitalization (OR 1.013, 95% CI 1.000-1.025), and the presence of post-COVID pain at T1 (OR 11.02, 95% CI 8.493-14.305) were factors associated with musculoskeletal post-COVID pain 1 year after hospitalization. In conclusion, musculoskeletal post-COVID pain remains highly prevalent 1 year after hospitalization. Female sex, previous history of pain symptoms, pain symptoms at onset, and days at hospital were factors associated with musculoskeletal post-COVID pain 1 year after hospitalization.
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Randomized Controlled Trial
Disentangling self from pain: mindfulness meditation-induced pain relief is driven by thalamic-default mode network decoupling.
For millenniums, mindfulness was believed to diminish pain by reducing the influence of self-appraisals of noxious sensations. Today, mindfulness meditation is a highly popular and effective pain therapy that is believed to engage multiple, nonplacebo-related mechanisms to attenuate pain. Recent evidence suggests that mindfulness meditation-induced pain relief is associated with the engagement of unique cortico-thalamo-cortical nociceptive filtering mechanisms. ⋯ Preregistered (NCT03414138) whole-brain analyses revealed that mindfulness meditation-induced analgesia was moderated by greater thalamus-precuneus decoupling and ventromedial prefrontal deactivation, respectively, signifying a pain modulatory role across functionally distinct neural mechanisms supporting self-referential processing. Two separate preregistered seed-to-seed analyses found that mindfulness meditation-based pain relief was also associated with weaker contralateral thalamic connectivity with the prefrontal and primary somatosensory cortex, respectively. Thus, we propose that mindfulness meditation is associated with a novel self-referential nociceptive gating mechanism to reduce pain.
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Pain is common in chronic pancreatitis (CP) and profoundly reduces quality of life (QoL). Multiple underlying mechanisms contribute to a heterogenous pain experience and reduce efficacy of pain management. This study was designed to characterize the distribution of mechanism-based pain phenotypes in painful CP. ⋯ Other factors, including pain medication use and healthcare utilization, did not differ between groups based on pain type. Subjects in the Both group had significantly worse health and QoL scores relative to those with nociceptive-only pain, suggesting that using psychosocial pain surveys may be useful for understanding pain subtypes in patients with CP. Additional research is needed to identify biochemical and biophysical signatures that may associate with and predict responses to mechanism-specific interventions.
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Targeted muscle reinnervation (TMR) is a clinical intervention that is rapidly becoming common in major limb amputation to prevent or reduce amputation-related pain. However, TMR is much less effective when applied long after injury compared with acute TMR. Since the mechanisms governing pain relief in TMR of amputated nerves are unknown, we developed a preclinical model as a platform for mechanistic examination. ⋯ In this model, the pain phenotype induced by nerve transection is reduced by TMR when performed within 3 weeks after injury. However, TMR delayed 12 weeks after injury fails to reduce pain behaviors. This replicates clinical experience with limb amputation, supporting validity of this model for examining the mechanisms of TMR analgesia.