Browse by Audience
In recent years, studying the central mechanism of itch has gained momentum. However, a proper meta-analysis has not been conducted in this domain. In this study, we tried to respond to this need. A systematic search and a meta-analysis were carried out to estimate the central mechanism of itch. The itch matrix comprises the thalamus and the parietal, secondary somatosensory, insular and cingulate cortices. We have shown that the basal ganglia (BG) play an important role in itch reduction. Finally, we explored itch processing in AD patients and observed that the itch matrix in these patients was different. In conclusion, this is the first meta-analysis on the central mechanisms of itch perception and processing. Our study demonstrated that different modalities of itch induction can produce a common pattern of activity in the brain and provided further insights into understanding the underlying nature of itch central perception.
Learn More >The sodium channel Nav1.7 is a master regulator of nociceptive input into the central nervous system. Mutations in this channel can result in painful conditions and produce insensitivity to pain. Despite being recognized as a "poster child" for nociceptive signaling and human pain, targeting Nav1.7 has not yet produced a clinical drug. Recent work has illuminated the Nav1.7 interactome, offering insights into the regulation of these channels and identifying potentially new druggable targets. Among the regulators of Nav1.7 is the cytosolic collapsin response mediator protein 2 (CRMP2). CRMP2, modified at lysine 374 (K374) by addition of a small ubiquitin-like modifier (SUMO), bound Nav1.7 to regulate its membrane localization and function. Corollary to this, preventing CRMP2 SUMOylation was sufficient to reverse mechanical allodynia in rats with neuropathic pain. Notably, loss of CRMP2 SUMOylation did not compromise other innate functions of CRMP2. To further elucidate the in vivo role of CRMP2 SUMOylation in pain, we generated CRMP2 K374A knock-in (CRMP2) mice in which Lys374 was replaced with Ala. CRMP2 mice had reduced Nav1.7 membrane localization and function in female, but not male, sensory neurons. Behavioral appraisal of CRMP2 mice demonstrated no changes in depressive or repetitive, compulsive-like behaviors and a decrease in noxious thermal sensitivity. No changes were observed in CRMP2 mice to inflammatory, acute, or visceral pain. By contrast, in a neuropathic model, CRMP2 mice failed to develop persistent mechanical allodynia. Our study suggests that CRMP2 SUMOylation-dependent control of peripheral Nav1.7 is a hallmark of chronic, but not physiological, neuropathic pain.
Learn More >To clarify whether photoreception of intrinsically photosensitive retinal ganglion cells (ipRGCs) is related to migraine, we investigated the relationship between hemodynamic responses related to neural activity and visual stimulation of ipRGCs. It has been established that photoreception in ipRGCs is associated with photophobia in migraine. However, the relationship between visual stimulation of ipRGCs and hemodynamic responses in the visual cortex has not been clarified. Hemodynamic responses in the visual cortex were measured using functional near-infrared spectroscopy (fNIRS) as signals reflecting changes in oxygenated and deoxygenated hemoglobin concentrations. Different types of visual stimulation generated by a metamerism method were applied to the peripheral field of the eye of patients with migraine (N = 20) and healthy participants (N = 21). The stimulation intensity on the retina was controlled using an artificial pupil. In the primary visual cortex of patients with migraine, statistically significant changes in fNIRS signals dependent on visual stimulation intensity applied to ipRGCs were observed (p < 0.01), while no such changes were observed in healthy participants. These results reveal that visual stimulation of ipRGCs projecting to the primary visual cortex is involved in hemodynamic responses in patients with migraine, suggesting that ipRGCs, in addition to photometric values related to cones, are associated with migraine.
Learn More >Chronic pain (1) and chronic pain that frequently limits life or work activities, referred to in this report as high-impact chronic pain (2), are among the most common reasons adults seek medical care (3) and are associated with decreased quality of life, opioid dependence, and poor mental health (1,4,5). This report examines chronic pain and high-impact chronic pain in the past 3 months among U.S. adults aged 18 and over by selected demographic characteristics and urbanization level.
Learn More >Low back pain is one of the leading causes of disability worldwide. Exercise therapy is widely recommended to treat persistent non-specific low back pain. While evidence suggests exercise is, on average, moderately effective, there remains uncertainty about which individuals might benefit the most from exercise.
Learn More >Approximately 40% of childhood cancer survivors experience chronic pain, with many also reporting pain-related disability. Given associations established in the general population among respiration, anxiety, and pain, continuous tracking and feedback of respiration may help survivors manage pain.
Learn More >Examine the effectiveness of specific modes of exercise training in non-specific chronic low back pain (NSCLBP).
Learn More >Self-compassion is associated with disability, pain-related anxiety as well as depression and anger in patients with chronic pain. However, the unique value of self-compassion versus other concepts such as psychological flexibility and self-esteem is unknown. The present study therefore aimed to clarify these relationships. Individuals with chronic pain (N = 872) and without chronic pain (N = 356) took part in a longitudinal study. Participants completed self-report instruments: Pain Disability Index (PDI), Pain Catastrophizing Scale (PCS), Pain Anxiety Symptom Scale (PASS-20), Patient Health Questionnaire (PHQ-9), State Trait Anger Expression Inventory (STAXI), Self-Compassion Scale (SCS), Psychological Inflexibility in Pain Scale (PIPS) and Rosenberg Self-Esteem Scale (RSES). Assessments were repeated after 8 weeks. We found differences in baseline levels of all relevant variables except for anger-out and anger-control between people with and without chronic pain. Subsequently, we computed a path model analysis regarding individuals suffering from chronic pain (N), addressing the predictive value of reduced uncompassionate self-responding (RUS), compassionate self-responding (CS), avoidance (PIPS), cognitive fusion (PIPS) and self-esteem (RSES) regarding pain-related (PDI, PCS, PASS) and emotional variables (PHQ-9, STAXI). Avoidance predicted disability, catastrophizing, anxiety and depression. RUS predicted catastrophizing and pain-related anxiety. Self-esteem predicted depression. CS and cognitive fusion had no unique predictive value. The model explained 65.4%-72.1% of the variance in pain-related variables, 68.7% of the variance in depression and 38.7%-60.7% in the variance of anger-related variables. In conclusion, psychological flexibility, in terms of avoidance, seems to be more relevant for chronic pain than self-compassion. Future research should focus on subgroups and tailored-treatment approaches. SIGNIFICANCE: Applying a longitudinal design, this study examined the predictive value of self-compassion regarding pain, depression and anger. The relevance of self-compassion was compared to psychological flexibility and self-esteem. We can conclude that psychological flexibility, in terms of avoidance behaviour, is the most relevant predictor concerning pain.
Learn More >Headache is a frequent complaint in COVID-19 patients. However, no detailed information on headache characteristics is provided in these reports. Our objective is to describe the characteristics of headache and the cerebrospinal fluid (CSF) profile in COVID-19 patients, highlighting the cases of isolated intracranial hypertension.
Learn More >