Pain
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Randomized Controlled Trial Multicenter Study
Efficacy and safety of tanezumab versus naproxen in the treatment of chronic low back pain.
Tanezumab is a humanized monoclonal antibody that specifically inhibits nerve growth factor as a treatment for chronic pain. This phase IIB study investigated the efficacy and safety of tanezumab for chronic low back pain vs placebo and naproxen. Patients (N=1347) received intravenous tanezumab (5, 10, or 20mg every 8weeks), naproxen (500mg twice daily), or placebo. ⋯ The most frequently reported adverse events resulting in discontinuation of tanezumab treatment were arthralgia and paresthesia; the highest frequency was observed with tanezumab 20mg (both 1.4%). Serious adverse event incidence was similar across treatments. In conclusion, tanezumab provided significantly greater improvement in pain, function, and global scores vs placebo and naproxen in patients with chronic low back pain.
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Comparative Study Controlled Clinical Trial
Diminished neurokinin-1 receptor availability in patients with two forms of chronic visceral pain.
Central sensitization and dysregulation of peripheral substance P and neurokinin-1 receptor (NK-1R) signaling are associated with chronic abdominal pain in inflammatory bowel disease (IBD) and irritable bowel syndrome (IBS). Although positron emission tomography (PET) has demonstrated that patients with injury-related chronic pain have diminished NK-1R availability in the brain, it is unknown whether these deficits are present in IBD and IBS patients, who have etiologically distinct forms of non-injury-related chronic pain. This study's aim was to determine if patients with IBD or IBS exhibit deficits in brain expression of NK-1Rs relative to healthy controls (HCs), the extent to which expression patterns differ across patient populations, and if these patterns differentially relate to clinical parameters. ⋯ BP in a subset of these regions was robustly related to discrete clinical parameters in each patient population. Widespread deficits in NK-1R BP occur in IBD and, to a lesser extent, IBS; however, discrete clinical parameters relate to NK-1R BP in each patient population. This suggests that potential pharmacological interventions that target NK-1R signaling may be most effective for treating distinct symptoms in IBD and IBS.
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To characterize the contribution of interleukin-6 (IL-6) to spinal cord injury pain (SCIP), we employed a clinically relevant rat contusion model of SCIP. Using Western blots, we measured IL-6 levels in lumbar segments (L1-L5), at the lesion site (T10), and in the corresponding lumbar and thoracic dorsal root ganglia (DRG) in 2 groups of similarly injured rats: (a) SCI rats that developed hind-limb mechanical allodynia (SCIP), and (b) SCI rats that did not develop SCIP. Only in SCIP rats did we find significantly increased IL-6 levels. ⋯ We also showed that IL-6-R Ab partially reversed SCI-induced decreases in the protein levels of the glutamate transporter GLT-1 12hours and 8days after Ab injection, which may explain the lasting analgesic effect of the Ab in SCIP rats. A link between reactive astrocytes IL-6-GLT-1 has not been previously shown. Given that the humanized IL-6-R Ab tocilizumab is Food and Drug Administration-approved for rheumatoid arthritis, we are proposing tocilizumab as a novel and potentially effective treatment for SCIP.