Abstract
The peripheral T-cell pool undergoes a striking age associated remodeling which is accelerated by progressive insulin resistance. Exercise training is known to delay several aspects of T-cell senescence. The purpose of the current study was to investigate the effect of 3 weeks regular concentric or eccentric endurance exercise training on the composition of the T-cell compartment in pre-diabetic subjects. Sixteen male older adults with impaired glucose tolerance were recruited and performed either concentric exercise (CE) or eccentric exercise (EE) walking 3 times a week for 3 weeks. Fasting venous blood sampling was performed before training and after the training intervention. Various T-cell subpopulations were analyzed by flow cytometry. We did not find significant time × group effects (interaction) but found several significant time effects for cell type ratios and cell subsets proportions. There was an increase of the CD4+/CD8+ (0.55 ± 0.85%; p = 0.033) and CD4+/CD3+ ratio (5.63 ± 8.44%; p = 0.018) and a decrease of the CD8+/CD3+ ratio (-0.95 ± 1.64%; p = 0.049) after training. We found proportional increases of CD4+/CCR7+/CD45RO+ central memory cells (5.02 ± 7.68%; p = 0.030), naïve CD8+/CCR7+/CD45RO- (3.00 ± 6.68%; p = 0.047) and CD8+/CCR7+/CD45RO+ central memory cells (3.01 ± 3.70%; p = 0.009), while proportions of CD4+/CCR7-/CD45RO- TEMRA cells (-2.17 ± 4.66%; p = 0.012), CD8+/CCR7-/CD45RO- TEMRA cells (-5.11 ± 7.02%; p = 0.018) and CD16+ cells (-4.67 ± 6.45%; p = 0.016) decreased after training. 3 weeks of either CE or EE were effective in reversing hallmarks of T-cell senescence in pre-diabetic subjects. It is suggested that exercise stimulates production and mobilization of naïve T-cells, while differentiated TEMRA cells might disappear by apoptosis.
Highlights
Due to increases in human life expectancy, aging is regarded as one of the biggest health issues worldwide
A major component of this change is represented by an inverted CD4+/CD8+ T-cell ratio which appears in parallel to a decline in naïve T-cell numbers and the accumulation of highly differentiated memory cells (Pawelec et al, 2010)
We found a significant increase of the relative proportion of CD4+/CCR7+/CD45RO+ central memory cells (F(1,13) = 5.912; p = 0.030) and a significant decrease of CD4+/CCR7−/CD45RO− terminally differentiated effector memory (TEMRA) cells (p = 0.012) and the relative proportion of CD16+ cells (F(1,13) = 7.617; p = 0.016) after training (Table 1)
Summary
Due to increases in human life expectancy, aging is regarded as one of the biggest health issues worldwide. Several functions of the immune system experience dramatic changes, which fundamentally affect health and survival This process termed “immunosenescence” is complex and affects almost most cellular and humoral components of immunity. These changes have noticeable consequences for the effectiveness of immune responses, the vulnerability to infection, the efficacy of vaccination, and reactivation of latent viruses in aging individuals. Together, these progressive deficits result in increased morbidity and mortality (Castle, 2000; Pawelec et al, 2010). The IRP represents a cluster of immunological parameters, which was shown to be associated with a poor immune function in elderly and predictive of earlier mortality (Wikby et al, 1998)
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