Pain
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Nonpharmacological interventions are recommended for the treatment of fibromyalgia, but there is a lack of knowledge about the cost-effectiveness of these interventions. The aim of this study was to systematically review economic evaluations of educational, physical, and psychological interventions for the treatment of fibromyalgia. The search was performed in PUBMED, EMBASE, CINAHL, Cochrane Library, Physiotherapy Evidence Database, PsycINFO, EconLit, National Health Service Economic Evaluation Database, and Health Technology Assessment. ⋯ Over a 12-month time horizon, healthcare costs for the psychological intervention were significantly lower than for usual care (mean difference: $-538, 95% CI: -917 to -158). Incremental cost-effectiveness ratios for quality-adjusted life-years and impact of fibromyalgia showed that the psychological intervention was cost-effective compared with other interventions and control conditions. There is a need of more economic evaluations conducted alongside randomized controlled trials with interventions recommended for the treatment of fibromyalgia, such as physical exercise.
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Endometriosis (ENDO) and interstitial cystitis/bladder pain syndrome (IC/BPS) are chronic pain conditions for which better treatments are urgently needed. Development of new therapies with proven clinical benefit has been slow. We have conducted a review of existing preclinical in vivo models for ENDO and IC/BPS in rodents, discussed to what extent they replicate the phenotype and pain experience of patients, as well as their relevance for translational research. ⋯ This analysis highlights the wide variety of models used, limiting reproducibility and translation of results. We recommend refining models so that they better reflect clinical reality, sharing protocols, and using standardized endpoints to improve reproducibility. We are addressing this in our project Innovative Medicines Initiative-PainCare/Translational Research in Pelvic Pain.
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Pain is a subjective experience with significant individual differences. Laboratory studies investigating pain thresholds and experimental acute pain have identified structural and functional neural correlates. However, these types of pain stimuli have limited ecological validity to real-life pain experiences. ⋯ Peak pain did, however, positively correlate with baseline resting-state functional connectivity between the thalamus contralateral to the separator and bilateral insula, and negatively correlated with connectivity between the periaqueductal gray (PAG) and core nodes of the default mode network (medial prefrontal and posterior cingulate cortices). The ascending (thalamic) nociceptive and the descending (PAG) pain modulatory pathways at baseline each explained unique variation in peak pain intensity ratings. In sum, preinterventional functional neural architecture of both systems determined the individual pain experience to a subsequent ecologically valid pain stimulus.
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Migraine pathophysiology has been suggested to include dysregulation of the endocannabinoid system (ES). We simultaneously evaluated plasma anandamide (AEA) and palmitoylethanolamide (PEA) levels and spinal sensitization in a validated human model of migraine based on systemic nitroglycerin (NTG) administration. Twenty-four subjects with episodic migraine (MIG) and 19 healthy controls (HC) underwent blood sampling and investigation of nociceptive withdrawal reflex thresholds (RTh: single-stimulus threshold; TST: temporal summation threshold) before and 30 (T30), 60 (T60), and 120 (T120) minutes after sublingual NTG administration (0.9 mg). ⋯ We found no significant correlations between the ES and neurophysiological parameters. Our findings suggest a role for PEA in the ictal phase of episodic migraine. The ES does not seem to be directly involved in the modulation of NTG-induced central sensitization, which suggests that the observed PEA increase and spinal sensitization are parallel, probably unrelated, phenomena.
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Glycinergic neurons and glycine receptors (GlyRs) exert a critical control over spinal nociception. Prostaglandin E2 (PGE2), a key inflammatory mediator produced in the spinal cord in response to peripheral inflammation, inhibits a certain subtype of GlyRs (α3GlyR) that is defined by the inclusion of α3 subunits and distinctly expressed in the lamina II of the spinal dorsal horn, ie, at the site where most nociceptive nerve fibers terminate. Previous work has shown that the hyperalgesic effect of spinal PGE2 is lost in mice lacking α3GlyRs and suggested that this phenotype results from the prevention of PGE2-evoked protein kinase A (PKA)-dependent phosphorylation and inhibition of α3GlyRs. ⋯ In behavioral experiments, they showed no alterations in baseline nociception, but were protected from the hyperalgesic effects of intrathecally injected PGE2 and exhibited markedly reduced inflammatory hyperalgesia. These behavioral phenotypes closely recapitulate those found previously in GlyR α3-deficient mice. Our results thus firmly establish the crucial role of PKA-dependent phosphorylation of α3GlyRs in inflammatory hyperalgesia.