Senescence of human skeletal muscle impairs the local inflammatory cytokine response to acute eccentric exercise

The impact of aging on the cytokine response of human skeletal muscle to exercise‐induced injury remains poorly understood. We enrolled physically active, young (23–35 years old, n =15) and old (66–78 years old, n =15) men to perform 45 min of downhill running (16% descent) at 75% VO 2max . Biopsies of vastus lateralis were obtained 24 h before and 72 h after acute eccentric exercise. Transcripts for inflammatory (TNF‐α, IL‐1β) and anti‐inflammatory cytokines (IL‐6, TGF‐β 1 ) were quantified by real‐time PCR. Before exercise, cytokine transcripts did not differ with age. At old age, exercise induced a blunted accumulation of transcripts encoding the pan‐leukocyte surface marker CD18 (young: 10.1‐fold increase, P <0.005; old: 4.7‐fold increase, P =0.02; young vs. old: P <0.05). In both age groups, CD18 transcript accumulation strongly correlated with TNF‐α (young, r =0.87, P <0.001; old, r =0.72, P =0.002) and TGF‐β 1 transcript accumulation (young, r =0.80, P <0.001; old, r =0.64, P =0.008). At old age, there was no correlation between IL‐1 β and CD18 transcript accumulation. Furthermore, exercise induced IL‐6 transcript accumulation in young (3.6‐fold, P =0.057) but not in old men. Our results suggest that aging impairs the adaptive response of human skeletal muscle to eccentric exercise by differential modulation of a discrete set of inflammatory and anti‐inflammatory cytokine genes.