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Multidisciplinary pain management (MPM) is a generally-accepted method for treating chronic pain, but heterogeneous outcome measures provide only limited conclusions concerning its effectiveness. Therefore, further studies on the effectiveness of MPM are needed to identify subgroups of patients who benefit, or do not benefit, from these interventions. Our aim was to analyze health-related quality of life (HRQoL) changes after MPM and to identify factors associated with treatment outcomes.
Learn More >Both in vivo neuropharmacology and optogenetic stimulation can be used to decode neural circuitry, and can provide therapeutic strategies for brain disorders. However, current neuronal interfaces hinder long-term studies in awake and freely behaving animals, as they are limited in their ability to provide simultaneous and prolonged delivery of multiple drugs, are often bulky and lack multifunctionality, and employ custom control systems with insufficiently versatile selectivity for output mode, animal selection and target brain circuits. Here, we describe smartphone-controlled, minimally invasive, soft optofluidic probes with replaceable plug-like drug cartridges for chronic in vivo pharmacology and optogenetics with selective manipulation of brain circuits. We demonstrate the use of the probes for the control of the locomotor activity of mice for over four weeks via programmable wireless drug delivery and photostimulation. Owing to their ability to deliver both drugs and photopharmacology into the brain repeatedly over long time periods, the probes may contribute to uncovering the basis of neuropsychiatric diseases.
Learn More >This study was performed to test whether the risk of developing chronic widespread pain (CWP) in those with regional pain was augmented in those with symptoms of neuropathic pain (NP). Persons free of CWP completed the Douleur Neuropathique 4 (scores ≥3 indicating NP); demographics; Hospital Anxiety and Depression scale; Pittsburgh Sleep Quality Index; and pain medications. Participants were classified as having no pain, regional pain with no symptoms of NP ((Equation is included in full-text article.)), or regional pain with symptoms of NP (NP). At the 12-month follow-up, participants with CWP were identified. Logistic regression estimated the odds ratio, with 95% confidence intervals, of CWP in the (Equation is included in full-text article.)and NP groups compared with no pain, and NP compared with (Equation is included in full-text article.). Partial population attributable risks estimated the proportion of CWP attributable to baseline (Equation is included in full-text article.)or NP exposure. One thousand one hundred sixty-two participants completed the baseline DN4 and provided pain data at follow-up: 523 (45.0%) had no baseline pain, 562 (48.4%) (Equation is included in full-text article.), and 77 (6.6%) NP. One hundred fifty-three (13.2%) had CWP at 12 months: 19 (3.6%) no pain, 108 (19.2%) (Equation is included in full-text article.), and 26 (33.8%) NP. (Equation is included in full-text article.)(2.9 [1.9-4.3]) and NP (2.1 [1.1-4.0]) predicted CWP after adjusting for demographics, Hospital Anxiety and Depression scale, Pittsburgh Sleep Quality Index, and medications. The partial population attributable risk was 41.3% (25.2-54.0) for (Equation is included in full-text article.)and 6.0% (0.1-11.6) for NP. The NP group were not more likely to develop CWP when compared directly with (Equation is included in full-text article.)(1.5 [0.8-2.8]). Neuropathic pain was relatively rare and predicted a small number of new-onset CWP cases. Using these estimates, treatments targeting NP would at best prevent 6% of CWP cases.
Learn More >This study investigated the analgesic effects of two doses (15 and 65 mg) of PF-06372865, a novel α2/α3/α5 gamma-aminobutyric acid A (GABA) subunit selective partial positive allosteric modulator (PAM), compared with placebo and pregabalin (300 mg) as a positive control.
Learn More >Persistent post-surgical pain is defined as pain localized to the area of surgery of at least 2-month duration and is unfortunately a common complication after breast cancer surgery. While there is insufficient evidence to support any preventative strategy, prior literature suggests possible efficacy of intravenous lidocaine and perioperative pregabalin in preventing persistent pain after surgery. To determine feasibility of conducting a larger definitive trial, we conducted a multicenter 2-by-2 factorial randomized placebo-controlled pilot trial of 100 female patients undergoing breast cancer surgery. Patients were randomized to receive an intraoperative lidocaine infusion (1.5 mg/kg bolus followed by 2 mg/kg/hr) or placebo and perioperative pregabalin (300 mg preoperatively, 75 mg twice daily for nine days) or placebo. All feasibility criteria were surpassed; recruitment of 100 patients within 42-weeks, follow-up rate of 100%, and study-drug compliance of ≥80%. At 3-months, 53% of patients reported persistent neuropathic pain. While there was no interaction between lidocaine and pregabalin, lidocaine reduced the development of persistent neuropathic pain (43.1% vs 63.3%; RR 0.68, 95% CI 0.47-1.0). Pregabalin did not reduce persistent pain (60% vs 46%; RR 1.3, 95% CI 0.90 to 1.90) and neither pregabalin nor lidocaine impacted acute postoperative pain, opioid consumption, pain interference, or quality of life. Our pilot trial successfully demonstrated feasibility and provided promising data for conducting further trials of intraoperative lidocaine infusions in breast cancer surgeries. Clinical trial number: NCT02240199 Perspectives: This article reports the findings of a pilot randomized controlled trial evaluating the effects of perioperative pregabalin and intraoperative lidocaine infusions in patients undergoing breast cancer surgery. This trial demonstrated feasibility of conducting a larger trial and provided promising data that these interventions may reduce the development of persistent pain.
Learn More >There is substantial evidence supporting the notion that the primary somatosensory (S1) cortex is an important structure involved in the perceptional component of pain. However, investigations have mainly focused on other pain-related formations, and few reports have been provided to investigate the synaptic plasticity in the S1 cortex in response to persistent pain. In the present study, we report that bee venom (BV) injection triggered an imbalance between excitatory and inhibitory synaptic transmission in the S1 cortex in rats. Using multi-electrode array (MED-64) recording, we found that BV-induced persistent inflammatory pain led to temporal and spatial enhancement of synaptic plasticity. Moreover, slice patch clamp recordings on identified pyramidal neurons demonstrated that BV injection increased presynaptic and postsynaptic transmission in excitatory synapses and reduced postsynaptic transmission in inhibitory synapses in the layer II/III neurons within the S1 cortex. In immunohistochemistry and western blot sections, the distribution and expression of total AMPA receptor subunits and GABA were unaffected, while the membrane fractions of GluR2 and GABA were decreased, and their cytosolic fractions were increased on the contrary. The change of GluR1 was opposite to that of GluR2, and GluR3 did not change significantly. Our studies therefore provide direct evidence for both presynaptic and postsynaptic changes in synapses within the S1 cortex in persistent nociception, which are probably related to the membrane trafficking of GluR1, GluR2 and GABA. PERSPECTIVE: Increased synaptic plasticity was detected in S1 following peripheral nociception, with enhanced excitatory and decreased inhibitory synaptic transmissions. Increased GluR1, while reduced GABAα1 and GluR2 membrane trafficking were detected. Therefore, the disrupted excitatory/inhibitory balance in transmissions is involved in nociception processing; and S1 can be a potential antinociceptive site.
Learn More >Chemotherapy-induced peripheral neuropathy (CIPN) is a devastating pain condition of cancer therapy that may force chemotherapy dose reduction or discontinuation. Since treatment options for CIPN are quite limited, we investigated the effect of 10% amitriptyline cream on neuropathic pain.
Learn More >Measuring brain activity in infants provides an objective surrogate approach with which to infer pain perception following noxious events. Here we discuss different approaches which can be used to measure noxious-evoked brain activity, and discuss how these measures can be used to assess the analgesic efficacy of pharmacological and non-pharmacological interventions. We review factors that can modulate noxious-evoked brain activity, which may impact infant pain experience, including gestational age, sex, prior pain, stress, and illness.
Learn More >The progressive increase in the prevalence of obesity in the population has resulted in increased healthcare costs and demands. Recent studies have revealed a positive correlation between pain and obesity, although the underlying mechanisms still remain unknown. Here, we aimed to clarify the role of microglia in altered pain behaviors induced by a high-fat diet (HFD) in male mice. We found that C57BL/6CR mice on a HFD exhibited spinal microglial reaction (increased cell number and up-regulated expression of p-p38 and CD16/32), increased tumor necrosis factor-α (TNF-α) mRNA and brain-derived neurotrophic factor (BDNF) protein as well as a polarization of spinal microglial toward a pro-inflammatory phenotype. Moreover, we found that when applied PLX3397 (a selective colony-stimulating factor-1 receptor (CSF1R) kinase inhibitor) to eliminate microglia of HFD-induced obesity mice, inflammation in the spinal cord was rescued, as were abnormal pain hypersensitivity. Intrathecal injection of Mac-1-saporin (a saporin-conjugated anti-mac1 antibody) resulted in decreased microglia and attenuated both mechanical allodynia and thermal hyperalgesia in HFD-fed mice. These results indicate that the pro-inflammatory functions of spinal microglia have a special relevance to abnormal pain hypersensitivity in HFD-induced obesity mice. In conclusion, our data suggest that HFD induces a classical reaction of microglia, characterized by an enhanced phosphorylation of p-38 and increased CD16/32 expression, which may in part contribute to increased nociceptive responses in HFD-induced obesity mice.
Learn More >The importance of calcitonin gene-related peptide (CGRP) in migraine pathogenesis is well established. Fremanezumab is a humanized IgG2a monoclonal antibody that binds to CGRP. Areas covered: In this paper we review the development of fremanezumab, from early development into approval. The authors focus on the efficacy and safety of fremanezumab in both migraine stages. The authors highlight studies conducted in special populations and focus on unique aspects of its development, as well as on clinical pearls supported by the data. Expert opinion: Fremanezumab was shown to be effective in episodic and chronic migraine, with a monthly and quarterly dose of administration, as monotherapy and add-on therapy. As with other monoclonal antibodies, anti-CGRP onset of action was remarkably quick, and the effect seems to be maintained over time. No overt safety concerns emerged from the clinical studies, although long term surveillance is necessary.
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