부산대학교 도서관

Introduction Aerobic capacity is a strong predictor of cardiovascular mortality. Whether aerobic capacity influences myocardial ischemia and reperfusion (IR) injury is unknown. Purpose To investigate the impact of intrinsic differences in aerobic capacity and the cardioprotective potential on IR injury. Methods We studied hearts from rats developed by selective breeding for high (HCR) or low (LCR) capacity for treadmill running. The rats were randomized to: (1) control, (2) local ischemic preconditioning (IPC) or (3) remote ischemic preconditioning (RIC) followed by 30 minutes of ischemia and 120 minutes of reperfusion in an isolated perfused heart model. The primary endpoint was infarct size. Secondary endpoints included uptake of labelled glucose, content of selected mitochondrial proteins in skeletal and cardiac muscle, and activation of AMP-activated kinase (AMPK). Results At baseline, running distance was 203±7 m in LCR vs 1905±51 m in HCR rats (p0.99, respectively). Phosphorylaion of AMPK did not differ between LCR and HCR controls. IPC did not modulate cardiac phosphorylation of AMPK. Glucose uptake during reperfusion was similar in LCR and HCR rats. IPC increased glucose uptake during reperfusion in LCR animals (p = 0.02). Mitochondrial protein content in skeletal muscle was lower in LCR than in HCR (0.77±0.10 arbitrary units (AU) vs 1.09±0.07 AU, p = 0.02), but not in cardiac muscle. Conclusion Aerobic capacity is associated with altered myocardial sensitivity to IR injury, but the cardioprotective effect of IPC is not. Glucose uptake, AMPK activation immediately prior to ischemia and basal mitochondrial protein content in the heart seem to be of minor importance as underlying mechanisms for the cardioprotective effects.
Author(s): Marie Vognstoft Hjortbak 1,2,*, Thomas Skjærlund Grønnebæk 3, Nichlas Riise Jespersen 1,2, Thomas Ravn Lassen 1,2, Jacob Marthinsen Seefeldt 1,2, Pernille Tilma Tonnesen 1,2, Rebekka Vibjerg Jensen 1,2, Lauren [...]