Dynamic changes in dna methylation status in peripheral blood Mononuclear cells following an acute bout of exercise: Potential impact of exercise-induced elevations in interleukin-6 concentration.

The aim of the present study was to examine the relationship between interleukin (IL)-6 concentrations and DNA methylation in the peripheral blood mononuclear cells (PBMCs) of trained runners after a bout of prolonged, strenuous exercise. Eight healthy trained males completed a treadmill run at 60% vVO(2max) for 120 min followed by a 5-km time trial in a fasted condition. Whole blood samples were taken prior to, immediately before and 24 h following exercise. From these samples, PBMCs were isolated for analysis and plasma IL-6 concentrations were measured. The methylation status of DNA extracted from PBMCs was analysed using the Illumina 27k methylation beadchip platform. Global DNA methylation status was unaltered immediately and up to 24 hours following a bout of prolonged exercise in comparison to pre-exercise. Despite no change in global DNA methylation, plasma IL-6 concentrations were significantly related to the DNA methylation status of 11 genes. Our study demonstrates that the methylome is stable, while discovering a novel link between exercise-induced increases in circulating IL-6 and the DNA methylation status of 11 individual genes. Based on our preliminary findings, the mechanisms by which changes in plasma IL-6 concentrations and DNA methylation in response to exercise interact require further study.

The reliability of the IL-6, sIL-6R and sgp130 response to a preloaded time trial.

Interleukin-6 (IL-6) is a cytokine that can mediate numerous biological actions including fatigue. Circulating IL-6 increases during prolonged exercise, and furthermore, the signalling receptors sIL-6R and sgp130 are also increased. The variability of the response of these markers to exercise is unknown; therefore, we examined the changes in these markers to a preloaded time trial bout of running. Nine males performed three identical trials where participants ran at 60% vVO2max for 2 h interspersed with 30 s at 90% vVO2max every 10 min, followed by a 5-km time trial. Blood samples were drawn at baseline, following the 2-h bout, post time trial, 1 h post time trial and the following morning. Results showed that between-subject variability (CVg) was greater than within-subject variation (CVi) for the three markers. IL-6, sIL-6R and sgp130 demonstrated a CVi of 15.3-25.5%, 15.0-17.6% and 6.2-9.4% variation, respectively, across the time points. When the data from the second and third trials were analysed independently, CVi was reduced which is supported by the time trial results for which CVi improve (4.7-2.4%). In conclusion, the results indicate that a large variation in response to exercise can be reduced following a habituation trial.