Exercise does not attenuate early CAD progression in a pig model.

PURPOSE: This study was designed to examine the effects of high-fat (HF) diet and subsequent exercise training (Ex) on coronary arteries of an animal model of early stage CAD. We hypothesized that HF diet would induce early stage disease and promote a proatherogenic coronary phenotype, whereas Ex would blunt disease progression and induce a healthier anti-inflammatory environment reflected by the increased expression of antioxidant capacity and the decreased expression of inflammatory markers in both the macrovasculature and the microvasculature of the coronary circulation. METHODS: Immunohistochemistry in left anterior descending and right coronary arteries and immunoblots in left anterior descending and left ventricular arterioles were used to characterize the effects of HF diet and Ex on the progression of coronary atherosclerosis. RESULTS: Our results revealed that HF diet promoted a proatherogenic coronary endothelial cell phenotype as evidenced by the endothelial expression of inflammatory and oxidative stress markers. Ex did not significantly alter any of these immunohistochemical markers in conduit arteries; however, Ex did increase antioxidant protein content in left ventricular arterioles. CONCLUSIONS: We conclude that, at this early stage of CAD, Ex did not seem to modify vascular cell phenotypes of conduit coronary arteries from proatherogenic to a more favorable antiatherogenic status; however, Ex increased antioxidant protein content in coronary arterioles. These findings also support the idea that endothelial phenotype expression follows different patterns in the macrovasculature and microvasculature of the coronary circulation.

Long-term exercise training does not alter brachial and femoral artery vasomotor function and endothelial phenotype in healthy pigs.

Although the beneficial effects of exercise training on conduit artery endothelial function are well-established in animals and humans with compromised basal function, whether exercise exerts favorable effects on a healthy endothelium is inconclusive. We sought to determine whether long-term exercise training enhances endothelial function in peripheral conduit arteries of healthy pigs. Using a retrospective analysis of data collected in our laboratory (n = 127), we compared in vitro brachial and femoral artery endothelium-dependent and -independent relaxation between a group of pigs that exercise-trained for 16-20 wk and a group that remained sedentary. No differences in vasomotor function were found between the 2 groups (P > 0.05). Additionally, in a subset of pigs (n = 16), expression levels of 18 proteins that are typically associated with the atherosclerotic process were measured by immunoblot analysis of endothelial cell scrapes obtained from the brachial and femoral arteries. We found no differences (P > 0.05) in endothelial gene expression between these exercise-trained and sedentary healthy pigs. These results indicate that pigs exhibiting the classic training-induced adaptations do not demonstrate enhanced endothelium-dependent dilation nor reveal a more atheroprotected endothelial cell phenotype in their brachial and femoral arteries than their sedentary but otherwise healthy counterparts.