Abstract 15584: Exercise Training Improves Left Ventricular Remodeling via Increase of the CD4+CD25+Foxp3+ Regulatory T Cells in Murine Heart Failure After Myocardial Infarction
Background: Myocardial remodeling after myocardial infarction (MI) causes heart failure. CD4+CD25+Foxp3+ regulatory T cells (Treg cells) have protective effects in wound healing and adverse ventricular remodeling after MI. Repeated aerobic exercises enhance Treg cell responses in animal studies. Repeated aerobic exercises also reduce myocardial remodeling after MI. Therefore, we hypothesized that repeated aerobic exercise training enhances Treg cell responses and reduces myocardial remodeling after MI.
Methods: Fourteen days after ligating the left anterior descending coronary artery, mice were randomly assigned two groups, exercise training group (ETG) and non-exercise training group (NTG). In ETG, mice performed swimming exercise training for ninety minutes twice a day for four weeks. After four weeks of training, mice were sacrificed, and cardiac histology and cardiac mRNA expression were examined. The number of Tregs (CD4+CD25+Foxp3+) was determined by flow cytometry in peripheral blood.
Results: Four weeks after exercise training, heart weight (HW)/tibia length (TL) and lung W (LW)/TL were significantly lower in ETG than those in NTG (HW/TL; 9.7 ± 0.4 vs. 12.1 ± 0.3 p <0.05, LW/TL 9.1 ± 0.5 vs. 11.3 ± 0.3 p <0.05). ETG significantly suppressed myocardial fibrosis in remote myocardium compared with NTG. Furthermore, mRNA levels of BNP and collagen I in the remote myocardium in ETG were lower compared with NTG (BNP; 0.7± 0.08 vs. 1.2 ± 0.09 p < 0.05, Collagen I; 0.8 ± 0.09 vs. 1.3 ± 0.1 p < 0.05). Interestingly, inflammatory cytokines, tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6), decreased in the remote myocardium of ETG compared with in that of NTG (TNF-α; 3.6 ± 0.5 vs. 5.9 ± 0.8, p < 0.05, IL-6; 0.6 ± 0.1 vs. 1.4 ± 0.4, p < 0.05). Moreover, the number of Treg cells increased in ETG blood compared with NTG blood (1.2 ± 0.1% vs. 0.2 ± 0.08%, p < 0.05).
Conclusion: Exercise training decreased lung congestion and reduced fibrosis and myocardial remodeling after MI. Furthermore, exercise training increased the number of Treg cells in blood and decreased serum TNF-α and IL-6. Exercise training reduced myocardial remodeling, maybe thorough upregulation of Treg.
Author Disclosures: A. Eguchi: None. T. Iwasaku: None. Y. Okuhara: None. M. Oboshi: None. Y. Naito: None. T. Mano: None. T. Masuyama: None. S. Hirotani: None.
- © 2016 by American Heart Association, Inc.