Age-related loss of associations between acute exercise-induced IL-6 and oxidative stress

Abstract

mediates many aspects of the exercise-induced acute-phase response, including upregulation of antioxidant defenses. Moreover, IL-6 synthesis is regulated in part by oxidative stress. This investigation tested the hypothesis that an IL-6-mediated acute-phase response after exercise provides negative-feedback protection against exerciseinduced oxidative stress. Healthy young (n ϭ 16, 26.4 Ϯ 1.8 yr) and older men (n ϭ 16, 71.1 Ϯ 2.0 yr) ran downhill for 45 min at 75% maximal oxygen consumption before and after a 12-wk period of supplementation with vitamin E (1,000 IU/day) or placebo. Circulating IL-6 and soluble IL-6 receptors, peripheral mononuclear cell production of IL-6, and IL-6 transcripts in muscle were measured before and within a 72-h time window after each acute exercise bout. At all time points plasma IL-6, IL-6 bioavailability, and C-reactive protein were higher in the older men; yet in response to exercise, young and older subjects experienced similar increases in these factors. Although the magnitude of postexercise changes in acutephase variables was independent of age, correlations among plasma, mononuclear cell, and muscle IL-6 and oxidative stress were evident only in young men (R 2 ϭ 0.64, 0.35, and 0.33, respectively). These changes in circulating IL-6 were closely associated with a prooxidant state (R 2 ϭ 0.47), whereas muscle IL-6 mRNA correlated with an antioxidant state (R 2 ϭ 0.65). Supplementation with vitamin E did not affect exercise-induced responses or differences between the young and old men in a consistent manner. Therefore, oxidative stress is linked to the acute-phase response after exercise in young men, but not in older men who had elevated acute-phase reactants, suggesting that further research is warranted to determine the basis for these differences.

Aging and its effects on inflammation in skeletal muscle at rest and following exercise-induced muscle injury

“…In contrast with the findings of the studies described above (26, 27, 153), another exercise study reported no differences in neutrophil counts or plasma IL-6 concentration between young (18 -35 yr) and elderly men (65-80 yr) after 45 min downhill running (130). The reasons for this disparity are unclear but may include differences between these exercise studies (26, 27, 130, 153) regarding the intensity and mode of exercise, the age, and habitual physical activity of the study participants.…”

“…The reasons for this disparity are unclear but may include differences between these exercise studies (26, 27, 130, 153) regarding the intensity and mode of exercise, the age, and habitual physical activity of the study participants. The plasma concentrations of IL-1ra, sTNF-␣R1, TGF-␤, and Creactive protein increased similarly after exercise in both young and elderly men (130,153). These findings suggest that not all systemic inflammatory reactions to exercise-induced muscle injury change with age.…”

Efeitos de diferentes intensidades de exercício sobre a concentração sérica de interleucinas

“…Estudos examinando o efeito de breves sessões de exercícios máximos (< 10 min) não encontraram alterações agudas nas concentrações séricas de IL-6 26 , entretanto, aumentos nos níveis circulantes desta citocina foram identi cados após 15 minutos 27 , 60 minutos 28 , e seis horas 29 de recuperação.…”

Interleukin-6 response to isokinetic exercise in elite athletes: relationships to adrenocortical function and to mechanical and myoelectric fatigue

“…In fact, it was demonstrated that the circulating cytokine levels increase with age and there is some evidence that ageing is associated with a remarkable cytokine response following stimulation, although these eVects are presently well-known only for elderly populations (Krabbe et al 2004). However, no studies have shown until now a positive relationship between contraction-related IL-6 production and age: Sacheck et al (2006) have recently found that the magnitude of post-exercise changes in acute phase variables is independent of age.…”