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Although analyses of pooled clinical trial data have reported how international populations respond to pregabalin by baseline neuropathic pain (NeP) severity, no studies have evaluated this specifically in patients from Japan. Thus, this post hoc pooled analysis evaluated the efficacy of pregabalin in Japanese subjects for treating moderate or severe baseline NeP.
Learn More >Chronic pain is increasingly recognized as a common and disabling problem for people living with HIV (PLWH). In a recent systematic review of psychosocial factors associated with chronic pain in PLWH, it was reported that very few studies to date have examined protective psychological factors that might help mitigate chronic pain for PLWH. The current study examined pain-specific resilience in relation to clinical and experimental pain, as well as pain coping in PLWH and chronic pain. Pain-specific resilience specifically refers to the ability to maintain relatively stable, healthy levels of psychological and physical functioning in the face of ongoing and persistent pain.
Learn More >Reduction in pain following multidisciplinary treatment is most often associated with a reduction in disability. To further elaborate the relationship between pain intensity and disability, the present study investigated three main questions: first, whether multidisciplinary treatment leads to a significant improvement in pain, disability and psychological variables (depression, pain acceptance and catastrophizing). Second, it was examined whether pain reduction may account for significant changes in the psychological variables (pre- to follow-up change scores). Finally, it was analyzed whether the psychological changes mediate the association between reduction in pain and in disability after controlling for age, sex and pain history.
Learn More >A decrease in glutamate in the medial prefrontal cortex (mPFC) has been extensively found in animal models of chronic pain. Given that the mPFC is implicated in emotional appraisal, cognition and extinction of fear, could a potential decrease in glutamate be associated with increased pessimistic thinking, fear and worry symptoms commonly found in people with chronic pain? To clarify this question, 19 chronic pain subjects and 19 age- and gender-matched control subjects without pain underwent magnetic resonance spectroscopy. Both groups also completed the Temperament and Character, the Beck Depression and the State Anxiety Inventories to measure levels of harm avoidance, depression, and anxiety, respectively. People with chronic pain had significantly higher scores in harm avoidance, depression and anxiety compared to control subjects without pain. High levels of harm avoidance are characterized by excessive worry, pessimism, fear, doubt and fatigue. Individuals with chronic pain showed a significant decrease in mPFC glutamate levels compared to control subjects without pain. In people with chronic pain mPFC glutamate levels were significantly negatively correlated with harm avoidance scores. This means that the lower the concentration of glutamate in the mPFC, the greater the total scores of harm avoidance. High scores are associated with fearfulness, pessimism, and fatigue-proneness. We suggest that chronic pain, particularly the stress-induced release of glucocorticoids, induces changes in glutamate transmission in the mPFC, thereby influencing cognitive, and emotional processing. Thus, in people with chronic pain, regulation of fear, worry, negative thinking and fatigue is impaired.
Learn More >Sex differences in gene expression are important contributors to normal physiology and mechanisms of disease. This is increasingly apparent in understanding and potentially treating chronic pain where molecular mechanisms driving sex differences in neuronal plasticity are giving new insight into why certain chronic pain disorders preferentially affect women vs. men. Large transcriptomic resources are now available and can be used to mine for sex differences to gather insight from molecular profiles using donor cohorts. We performed in-depth analysis of 248 human tibial nerve (hTN) transcriptomes from the GTEx Consortium project to gain insight into sex-dependent gene expression in the peripheral nervous system (PNS). We discover 149 genes with sex differential gene expression. Many of the more abundant genes in men are associated with inflammation and appear to be primarily expressed by glia or immune cells, with some genes downstream of Notch signaling. In women, we find the differentially expressed transcription factor SP4 that is known to drive a regulatory program, and may impact sex differences in PNS physiology. Many of these 149 differentially expressed (DE) genes have some previous association with chronic pain but few of them have been explored thoroughly. Additionally, using clinical data in the GTEx database, we identify a subset of DE, sexually dimorphic genes in diseases associated with chronic pain: arthritis and Type II diabetes. Our work creates a unique resource that identifies sexually dimorphic gene expression in the human PNS with implications for discovery of sex-specific pain mechanisms.
Learn More >Pain is highly prevalent in patients with Parkinson's disease (PD), but underlying pathophysiological mechanisms are largely unclear. Alterations in somatosensory processing might contribute to sensory abnormalities in PD.
Learn More >Previous studies have shown the efficacy of tapentadol (TP) for chronic cancer pain. We evaluated multiple effectiveness aspects of TP prolonged release on moderate-severe cancer-related pain, neuropathic pain (NeP), patient satisfaction, and quality of life.
Learn More >It has been generally thought that activation and sensitization of the trigeminovascular system may contribute to the pathogenesis of migraine. Nevertheless, there is little evidence on abnormalities in peripheral trigeminal afferent nerves from humans in vivo. Alterations of corneal nerves from the ophthalmic branch of the trigeminal nerve may support the notion that trigeminal afferent nerves are involved in migraine pathophysiology. The aim of the present study was to investigate the structural changes in corneal subbasal nerve plexus in patients with episodic migraine (EM) with in vivo confocal microscope (IVCM). In this cross-sectional observational study, 10 EM patients and 10 age- and sex-matched healthy controls were included. Analysis of IVCM images with Image J software was performed to quantify the changes in the corneal subbasal nerve plexus. EM patients showed an increase in nerve fiber length (25.0±2.65 vs 22.3±2.41 mm/mm, =0.047) and nerve fiber density (36.3±7.29 vs 30.5±6.19 fibers/mm, =0.104) as compared with normal controls, but this difference was not statistically significant. Nerve branching and tortuosity were significantly increased in the EM subjects compared to the normal subjects (91.3±13.8 vs 75.0±14.2 branches/mm, =0.030 and 2.30±0.46 versus 1.63±0.52, =0.011, respectively). In addition, nerve sprouts and increased number of Langerhans cells were observed in the EM patients. The morphologic changes of corneal subbasal nerve plexus and Langerhans cell aggregation suggest the presence of nerve regeneration and inflammation in EM. Furthermore, the alterations of corneal nerves from the ophthalmic branch of the trigeminal nerve offer support for the hypothesis that the peripheral trigeminal system may be involved in the pathogenesis of migraine.
Learn More >To investigate the prevalence of anxiety, depression and mixed anxiety and depressive disorder (MADD) and factors associated with these conditions in women with chronic pelvic pain (CPP) compared to a pain-free control group. A cross-sectional study was conducted with 100 women with CPP and 100 without CPP. The Hospital Anxiety and Depression Scale (HADS) was used to evaluate the presence of anxiety and depression. Sociodemographic, behavioral and clinical characteristics were investigated. Fisher's exact test was used to compare characteristics between groups. A log-binomial regression model was used, with adjustment for age, skin color, schooling, body mass index and pain. Prevalence ratios (PR), together with their 95% confidence intervals (CI), were calculated to investigate factors associated with anxiety, depression and MADD. The prevalence of anxiety was 66% in the CPP group and 49% in the controls (=0.02). Depression was identified in 63% of the women with CPP and in 38% of the controls (<0.01). MADD was present in 54% of the CPP group and in 28% of the controls (<0.01). In the adjusted analysis, CPP (PR=1.3; 95%CI: 1.1-1.6), physical abuse (PR=1.5; 95%CI: 1.2-1.8) and sexual abuse (PR=1.5; 95%CI: 1.1-1.8) were independently associated with anxiety. Women of 25 to 34 years of age were less likely to have anxiety (PR=0.6; 95%CI: 0.4-0.8). CPP (PR=1.6; 95%CI: 1.2-2.2), physical abuse (PR=1.3; 95%CI: 1.1-1.7) and sexual abuse (PR=1.7; 95%CI: 1.3-2.2) were independently associated with depression. CPP (PR=1.9; 95%CI: 1.3-2.7), smoking (PR=1.5; 95%CI: 1.1-2.1), physical abuse (PR=1.4; 95%CI: 1.1-1.9) and sexual abuse (PR=1.4; 95%CI: 1.1-1.8) were independently associated with MADD. The prevalence of anxiety, depression and MADD was higher in women with CPP compared to the pain-free controls. Factors associated with mental disorders were identified. The independent association between CPP and anxiety, depression and MADD was noteworthy. These findings suggest that systematic management of psychological factors could contribute towards improving the mental health of these women.
Learn More >This study reports on physicians' experiences with chronic pain management. For over a decade prescription opioids have been a primary treatment for chronic pain in North America. However, the current opioid epidemic has complicated long-standing practices for chronic pain management which historically involved prescribing pain medication. Caring for patients with chronic pain occurs within a context in which a growing proportion of patients suffer from chronic rather than acute conditions alongside rising social inequities.
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