Pain
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With less than 50% of patients responding to the current standard of care and poor efficacy and selectivity of current treatments, neuropathic pain continues to be an area of considerable unmet medical need. Biological therapeutics such as monoclonal antibodies (mAbs) provide better intrinsic selectivity; however, delivery to the central nervous system (CNS) remains a challenge. Granulocyte-macrophage colony-stimulating factor (GM-CSF) is well described in inflammation-induced pain, and early-phase clinical trials evaluating its antagonism have exemplified its importance as a peripheral pain target. ⋯ Functional analysis of glial cells revealed that pretreatment with GM-CSF potentiated lipopolysaccharide-induced release of proinflammatory cytokines. In summary, our data indicate that GM-CSF is a proinflammatory cytokine that contributes to nociceptive signalling through driving spinal glial cell secretion of proinflammatory mediators. In addition, we report a successful approach to accessing CNS pain targets, providing promise for central compartment delivery of analgesics.
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Randomized Controlled Trial
Can early oral prolonged-release oxycodone with or without naloxone reduce the duration of epidural analgesia after cystectomy? A 3-arm, randomized, double-blind, placebo-controlled trial.
Thoracic epidural analgesia (TEA) enhances recovery after bowel surgery. Early postoperative prolonged-release oral formulation of oxycodone or oxycodone/naloxone is potentially useful as a second analgesic step to reduce the duration of TEA. We hypothesized that oxycodone would decrease the duration of TEA and combined with naloxone preserve gastrointestinal function. ⋯ In the oxycodone group, we found 8/30 patients with ileus (27%) compared to 2/28 (7%) in the oxycodone/naloxone group and to 2/30 (7%) in the placebo group; (P = 0.031). Oxycodone, with or without naloxone, did not reduce the duration of TEA. Oxycodone alone led to a delayed return of bowel function, whereas the combination was not different from placebo.
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To standardize outcome reporting in clinical trials of patients with nonspecific low back pain, an international multidisciplinary panel recommended physical functioning, pain intensity, and health-related quality of life (HRQoL) as core outcome domains. Given the lack of a consensus on measurement instruments for these 3 domains in patients with low back pain, this study aimed to generate such consensus. The measurement properties of 17 patient-reported outcome measures for physical functioning, 3 for pain intensity, and 5 for HRQoL were appraised in 3 systematic reviews following the COSMIN methodology. ⋯ Various participants requested 1 free-to-use instrument per domain. Considering all issues together, recommendations on core instruments were formulated: Oswestry Disability Index version 2.1a or 24-item Roland-Morris Disability Questionnaire for physical functioning, NRS for pain intensity, and SF12 or 10-item PROMIS Global Health form for HRQoL. Further studies need to fill the evidence gaps on the measurement properties of these and other instruments.
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Numerous studies have shown associations between genetic variants and neuropathic pain disorders. Rare monogenic disorders are caused by mutations of substantial effect size in a single gene, whereas common disorders are likely to have a contribution from multiple genetic variants of mild effect size, representing different biological pathways. ⋯ Biobank cohort. Successfully replicated association with a neuropathic pain construct for 2 variants in IL10 underscores the importance of neuroimmune interactions, whereas genome-wide significant association with low back pain (P = 1.3e-8) and false discovery rate 5% significant associations with hip, knee, and neck pain for variant rs7734804 upstream of the MAT2B gene provide evidence of shared contributing mechanisms to overlapping pain conditions at the molecular genetic level.
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Patients with the same neuropathic pain disorder may have completely different sensory signs and symptoms yet receive the same medicinal treatment. New concepts suggest that patient stratification according to their pain mechanisms, reflected in their sensory phenotype, could be promising to implement an individualized therapy in neuropathic pain. ⋯ Recent prospective studies using stratification based on sensory phenotypes confirm this concept. In this article, we review the recent accomplishments towards an individualized pharmacological treatment of neuropathic pain.