👤 Deepak K Rajpal

Sleep and physical activity are modifiable behaviours linked to pain. Sleep disturbance often co-occurs with persistent pain and may contribute to its development. Exercise is a first-line treatment for chronic pain. Previous work showed that sleep disturbance worsens and prolongs postinjury pain behaviours, exercise mitigates these effects, and brain-derived neurotrophic factor may play a mechanistic role. Deeper insight requires a broader assessment of pain behaviours and systemic biomarkers related to inflammation, tissue repair, and neuromodulation. This study addresses these gaps. Twenty-nine adult female Sprague-Dawley rats performed an intensive lever-pulling task for 4 weeks to induce overuse injury and then underwent one of three 4-week interventions: intermittent sleep disturbance, voluntary exercise (via access to a running wheel), or both. Pain-related behaviours and 71 blood analytes were measured immediately preinjury, postinjury, and postintervention. Overuse injury decreased grip strength and increased mechanical sensitivity in the injured forepaws. After cessation of the injury inducing task, these changes persisted with sleep disturbance but recovered to, or exceeded, preinjury levels with exercise, even with concurrent sleep disturbance. Biomarker analyses revealed distinct neuroimmune responses to injury and sleep disturbance, particularly mediators of inflammation and neuroplasticity, that were offset by exercise. Correlations between biomarkers and behavioural outcomes support mechanistic links between injury, sleep, exercise, and recovery. Findings demonstrate that postinjury sleep disturbance induces neuroimmune changes that increase persistent pain vulnerability, whereas aerobic exercise counters these effects. This highlights the interaction between sleep and exercise in recovery and their potential as strategies to prevent and manage chronic pain. Show less

Rosacea is a common, chronic skin disease of variable severity with limited treatment options. The cause of rosacea is unknown, but it is believed to be due to a combination of hereditary and environmental factors. Little is known about the genetics of the disease. We performed a genome-wide association study (GWAS) of rosacea symptom severity with data from 73 265 research participants of European ancestry from the 23andMe customer base. Seven loci had variants associated with rosacea at the genome-wide significance level (P < 5 × 10-8). Further analyses highlighted likely gene regions or effector genes including IRF4 (P = 1.5 × 10-17), a human leukocyte antigen (HLA) region flanked by PSMB9 and HLA-DMB (P = 2.2 × 10-15), HERC2-OCA2 (P = 4.2 × 10-12), SLC45A2 (P = 1.7 × 10-10), IL13 (P = 2.8 × 10-9), a region flanked by NRXN3 and DIO2 (P = 4.1 × 10-9), and a region flanked by OVOL1and SNX32 (P = 1.2 × 10-8). All associations with rosacea were novel except for the HLA locus. Two of these loci (HERC-OCA2 and SLC45A2) and another precedented variant (rs1805007 in melanocortin 1 receptor) with an association P value just below the significance threshold (P = 1.3 × 10-7) have been previously associated with skin phenotypes and pigmentation, two of these loci are linked to immuno-inflammation phenotypes (IL13 and PSMB9-HLA-DMA) and one has been associated with both categories (IRF4). Genes within three loci (PSMB9-HLA-DMA, HERC-OCA2 and NRX3-DIO2) were differentially expressed in a previously published clinical rosacea transcriptomics study that compared lesional to non-lesional samples. The identified loci provide specificity of inflammatory mechanisms in rosacea, and identify potential pathways for therapeutic intervention. Show less

Hand grip strength is a widely used proxy of muscular fitness, a marker of frailty, and predictor of a range of morbidities and all-cause mortality. To investigate the genetic determinants of variation in grip strength, we perform a large-scale genetic discovery analysis in a combined sample of 195,180 individuals and identify 16 loci associated with grip strength (P<5 × 10 Show less