Increased expression of telomere-regulating genes in endurance athletes with long leukocyte telomeres

Abstract

Leukocyte telomeres shorten with age, and excessive shortening is associated with age-related cardiometabolic diseases. Exercise training may prevent disease through telomere length maintenance although the optimal amount of exercise that attenuates telomere attrition is unknown. Furthermore, the underlying molecular mechanisms responsible for the enhanced telomere maintenance observed in endurance athletes is poorly understood. We quantified the leukocyte telomere length and analyzed the expression of telomere-regulating genes in endurance athletes and healthy controls (both n = 61), using quantitative PCR. We found endurance athletes have significantly longer (7.1%, 208-416 nt) leukocyte telomeres and upregulated TERT (2.0-fold) and TPP1 (1.3-fold) mRNA expression compared with controls in age-adjusted analysis. The telomere length and telomere-regulating gene expression differences were no longer statistically significant after adjustment for resting heart rate and relative V̇O(2 max) (all P > 0.05). Resting heart rate emerged as an independent predictor of leukocyte telomere length and TERT and TPP1 mRNA expression in stepwise regression models. To gauge whether volume of exercise was associated with leukocyte telomere length, we divided subjects into running and cycling tertiles (distance covered per week) and found individuals in the middle and highest tertiles had longer telomeres than individuals in the lowest tertile. These data emphasize the importance of cardiorespiratory fitness and exercise training in the prevention of biological aging. They also support the concept that moderate amounts of exercise training protects against biological aging, while higher amounts may not elicit additional benefits.

Muscle-Enriched MicroRNAs Isolated from Whole Blood Are Regulated by Exercise and Are Potential Biomarkers of Cardiorespiratory Fitness

“…The subject characteristics are described elsewhere (Denham et al, 2016). Briefly, all subjects were apparently healthy, non-smokers, free from cardio-metabolic disease and were not taking any medication ( Table 1 ).…”

“…The study procedures have been outlined previously (Denham et al, 2015, 2016). Briefly, subjects were recruited by word of mouth and flyers posted around the University campus.…”

“…Subjects’ height, weight, and body mass index (BMI) were recorded, and a resting blood sample was collected. All subjects then completed a O 2 max test as previously described (Denham et al, 2016). The 19 young men involved in the acute exercise trial gave a second blood sample immediately after their O 2 max test.…”

The Effect of Resistance Training on Telomere Length in Women Recovering from Breast Cancer

“…Venous blood was donated in an overnight fasted state, collected into heparin tubes and frozen at −20 • C prior to DNA extraction. DNA extraction, yield, and purity as well as telomere length were assessed as previously described [19,20]. Briefly, frozen blood samples were thawed on ice and DNA was extracted from buffer coat leukocytes using the Purelink Genomic DNA Mini Kit following the manufacturer's guidelines (Thermo Fisher Scientific, Waltham, MA, USA).…”

“…Experiments comprised of DNA template or water (for no-template controls), and either 300 nM of forward and reverse primer for the telomere sequence or 300 nM of the forward and 500 nM of the reverse primer for the 36B4 sequence, were run on a Bio-Rad Thermocycler (CFX96 Touch Real-Time PCR Detection System, Bio-Rad, Hercules, CA, USA). Primer sets and thermocycling conditions were identical to those previously described [19]. Telomere length was expressed in arbitrary units as a T/S ratio, relative to a healthy 30-year-old woman using the 2 −(∆−∆Ct) method.…”