Articles: neuralgia.
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We have previously shown that intradermal injection of high-molecular-weight hyaluronan (500-1200 kDa) produces localized antihyperalgesia in preclinical models of inflammatory and neuropathic pain. In the present experiments, we studied the therapeutic effect of topical hyaluronan, when combined with each of 3 transdermal drug delivery enhancers (dimethyl sulfoxide [DMSO], protamine or terpene), in preclinical models of inflammatory and neuropathic pain. Topical application of 500 to 1200 kDa hyaluronan (the molecular weight range used in our previous studies employing intradermal administration), dissolved in 75% DMSO in saline, markedly reduced prostaglandin E 2 (PGE 2 ) hyperalgesia, in male and female rats. ⋯ The topical administration of a combination of hyaluronan with 2 other transdermal drug delivery enhancers, protamine and terpene, also attenuated CIPN hyperalgesia, an effect that was more prolonged than with DMSO vehicle. Repeated administration of topical hyaluronan prolonged the duration of antihyperalgesia. Our results support the use of topical hyaluronan, combined with chemically diverse nontoxic skin penetration enhancers, to induce marked antihyperalgesia in preclinical models of inflammatory and neuropathic pain.
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Neuropathic pain (NP) is defined as constant disabling pain secondary to a lesion or disease of the somatosensory nervous system. This condition is particularly difficult to treat because it often remains resistant to most treatment strategies. Despite the recent diversification of neurostimulation methods, some patients still suffer from refractory pain syndromes. The central role of the posterior insular cortex (PI) in the modulation of pain signaling and perception has been repeatedly suggested. The objective of this study is to assess whether epidural insular stimulation (IS) could reverse NP behavior. ⋯ These results suggest a significant reversal of NP symptoms after LF-IS and offer additional evidence that IS might be beneficial in the treatment of resistant NP syndromes through endogenous opioid secretion. Relying on our novel epidural IS model, further fine tuning of stimulation parameters might be necessary to achieve optimal therapeutic effects.
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Patients who suffer from long-term, neuropathic pain that proves refractory to conventional medical management are high consumers of health care resources and experience poorer physical and mental health than people with other forms of pain. Pharmacologic treatments have adverse effects; nonpharmacologic interventions have limitations. Spinal cord stimulation (SCS) is an effective treatment for neuropathic pain, although 30% to 40% of patients fail to achieve acceptable levels of pain relief. There are currently no objective methods to predict the success of SCS to treat neuropathic pain, and therefore, it is important to understand which patient factors may be predictive of a lack of response to SCS, to inform future patient treatment options. This study proposes a protocol for a systematic review and meta-analysis of published studies to examine these predictive factors. ⋯ This study seeks to provide a contemporary review of patient predictors of success of neuromodulation for neuropathic pain. We anticipate that findings may guide the use of neuromodulation in patient subgroups and the design and reporting of future clinical studies in this field.
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Using a model of combat and operational stress reaction (COSR), our lab recently showed that exposure to an unpredictable combat stress (UPCS) procedure prior to a thermal injury increases pain sensitivity in male rats. Additionally, our lab has recently shown that circulating extracellular vesicle-microRNAs (EV-miRNAs), which normally function to suppress inflammation, were downregulated in a male rat model of neuropathic pain. In this current study, male and female rats exposed to UPCS, followed by thermal injury, were evaluated for changes in circulating EV-miRNAs. ⋯ Consistent differences in EV-miRNAs are detectable in both COSR as well as during the development of mechanical sensitivity and potentially serve as key regulators, biomarkers, and targets in the treatment of COSR and thermal-injury induced mechanical sensitivity. PERSPECTIVE: This article presents the effects of unpredictable combat stress and thermal injury on EV-contained microRNAs in an animal model. These same mechanisms may exist in clinical patients and could be future prognostic and diagnostic biomarkers.
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Review
Research trends and hotspots of neuromodulation in neuropathic pain: A bibliometric analysis.
Neuropathic pain (NeuP), the result of a lesion or disease of the somatosensory nervous system, is tricky to cure clinically. Mounting researches reveal that neuromodulation can safely and effectively ameliorate NeuP. The number of publications associated with neuromodulation and NeuP increases with time. However, bibliometric analysis on the field is rare. The present study aims to analyze trends and topics in neuromodulation and NeuP research by using a bibliometric method. ⋯ The bibliometric analysis showed that the number of publications on neuromodulation and NeuP are increasing rapidly, especially in the past 5 years. "Motor cortex stimulation," "electrical stimulation," "spinal cord stimulation," "transcranial magnetic stimulation" and "mechanism" catch the most attention among researchers in this field.