Brain-derived neurotrophic factor (BDNF) participates in orchestrating the adaptive response to exercise. However, the importance of transient changes in circulating BDNF for eliciting whole-body and skeletal muscle exercise benefits in humans remains relatively unexplored. Here, we investigated effects of acute aerobic exercise and 3-month aerobic-strength training on serum, plasma and skeletal muscle BDNF in twenty-two sedentary older individuals (69.0 ± 8.0 yrs., 9 M/13F). BDNF response to acute exercise was additionally evaluated in young trained individuals (25.1 ± 2.1 yrs., 3 M/5F). Acute aerobic exercise transiently increased serum BDNF in sedentary (16%, p = .007) but not in trained elderly or young individuals. Resting serum or plasma BDNF was not regulated by exercise training in the elderly. However, subtle training-related changes of serum BDNF positively correlated with improvements in walking speed (R = 0.59, p = .005), muscle mass (R = 0.43, p = .04) and cognitive performance (R = 0.41, p = .05) and negatively with changes in body fat (R = -0.43, p = .04) and triglyceridemia (R = -0.53, p = .01). Individuals who increased muscle BDNF protein in response to 3-month training (responders) displayed stronger acute exercise-induced increase in serum BDNF than non-responders (p = .006). In addition, muscle BDNF protein content positively correlated with type II-to-type I muscle fiber ratio (R = 0.587, p = .008) and with the rate of post-exercise muscle ATP re-synthesis (R = 0.703, p = .005). Contrary to serum, acute aerobic exercise resulted in a decline of plasma BDNF 1 h post-exercise in both elderly-trained (-34%, p = .002) and young-trained individuals (-48%, p = .034). Acute circulating BDNF regulation by exercise was dependent on the level of physical fitness and correlated with training-induced improvements in metabolic and cognitive functions. Our observations provide an indirect evidence that distinct exercise-induced changes in serum and plasma BDNF as well as training-related increase in muscle BDNF protein, paralleled by improvements in muscle and whole-body clinical phenotypes, are involved in the coordinated adaptive response to exercise in humans.

中文翻译：

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急性和规律运动明显调节老年人血清、血浆和骨骼肌 BDNF

脑源性神经营养因子 (BDNF) 参与协调对运动的适应性反应。然而，循环 BDNF 的瞬时变化对于引发人体全身和骨骼肌运动益处的重要性仍然相对未探索。在这里，我们研究了急性有氧运动和 3 个月有氧力量训练对 22 名久坐不动的老年人（69.0 ± 8.0 岁，9 M/13F）的血清、血浆和骨骼肌 BDNF 的影响。在受过训练的年轻个体（25.1 ± 2.1 岁，3 M/5F）中还评估了对急性运动的 BDNF 反应。急性有氧运动会暂时增加久坐不动的血清 BDNF (16%, p = .007)，但不会在训练有素的老年人或年轻人中增加。静息血清或血浆 BDNF 不受老年人运动训练的调节。然而，血清 BDNF 的细微训练相关变化与步行速度 (R = 0.59, p = .005)、肌肉质量 (R = 0.43, p = .04) 和认知能力 (R = 0.41, p = .05) 的改善呈正相关) 和身体脂肪的变化 (R = -0.43, p = .04) 和甘油三酯血症 (R = -0.53, p = .01)。响应 3 个月训练而增加肌肉 BDNF 蛋白的个体（响应者）表现出比无响应者更强的急性运动诱导的血清 BDNF 增加（p = .006）。此外，肌肉 BDNF 蛋白含量与 II 型与 I 型肌纤维比率（R = 0.587，p = .008）和运动后肌肉 ATP 再合成率（R = 0.703，p = .005）。与血清相反，急性有氧运动导致训练后 1 小时血浆 BDNF 下降（-34%，p = . 002) 和受过年轻训练的人 (-48%, p = .034)。运动对急性循环 BDNF 的调节取决于身体健康水平，并与训练引起的代谢和认知功能改善相关。我们的观察提供了一个间接证据，表明运动引起的血清和血浆 BDNF 的明显变化以及肌肉 BDNF 蛋白的训练相关增加，同时伴随着肌肉和全身临床表型的改善，参与了对运动的协调适应性反应在人类。