Endurance Exercise Elevates Plasma Mature Brain-Derived Neurotrophic Factor through Child- and Adulthood, with Amplified Effects in Adults

BackgroundBrain-derived neurotrophic factor (BDNF) is a neurotrophin that plays a central role in neuronal health. BDNF exists in two primary isoforms, the mature form (mBDNF) and its precursor (proBDNF), with opposing downstream effects on neuronal function. The positive effect of exercise on plasma levels of the BDNF-isoforms has been extensively studied in adults. However, equivalent investigations are lacking in children and youth. MethodsTwenty healthy children (9-12 years old), 19 adolescents (13-17 years old), and 39 adults (23-49 years old) donated venous blood before and after a 45-minute run. Platelet-poor plasma was analyzed for pro- and mBDNF using enzyme-linked immunosorbent assay. Maximal oxygen uptake and anthropometric data were assessed in all participants, while Tanner stage, circulating sex hormones, and accelerometry-based activity level were assessed in children and adolescents. ResultsWe found that children, adolescents, and adults have similar basal levels of pro-(337-543 pg x ml-1) and mBDNF (650-1111 pg x ml-1). For children and adolescents, basal levels of mBDNF correlated with average time spent in vigorous activity (r=0.5794, p=0.0015). In response to acute endurance exercise, mBDNF increased by 701 {+/-} 946, 1232 {+/-} 1105, and 1557 {+/-} 1168 pg x ml-1 in children, adolescents, and adults, respectively. The acute endurance exercise did not affect proBDNF levels (p>0.05). ConclusionOur results demonstrate that basal plasma pro- and mBDNF levels do not depend on age and maturity. Plasma mBDNF levels increase following endurance exercise in all age groups, but to a greater extent in adults. Highlights/ImpactO_LIWe show that in children and adolescents, regular vigorous physical activity is key to increased basal levels of plasma mBDNF, a factor linked to neuroplasticity and brain health. C_LIO_LIThe ability to elevate mBDNF through exercise is present across all age groups, with the greatest increase in adults. C_LIO_LIThe mBDNF response to physical exercise seems to be independent of underlying physical fitness. C_LIO_LIOur findings suggest that basal plasma mBDNF levels may reflect the cumulative effects of repeated exercise rather than an individuals overall physical fitness. C_LI