DNA Methylation and Vascular Function in Obesity: Role of Exercise and Weight Loss

The long-term goal of this study is to identify valid targets and strategies for the prevention and treatment of obesity-related cardiovascular disease. Obesity is characterized by a large accumulation of fat tissues that secrete numerous inflammatory mediators (called adipocytokines), generating a systemic inflammatory state. These adipocytokines induce vascular dysfunction which is the initial step towards developing cardiovascular disease. Obesity is affected by environmental factors such as diet and physical activity. These factors induce epigenetic changes, which are changes that affect gene expression without altering the DNA sequence. One of these epigenetic modifications is the reduction in DNA methylation (referred to as hypomethylation) resulting in subsequent increases in gene expression. Preliminary data of the current study showed that the extracted DNA from fat tissues of obese subjects is hypomethylated compared to non-obese controls. DNA hypomethylation correlated significantly with higher expression of adipocytokines and impaired vasodilation in obese subjects. Therefore, the main hypothesis in this study is that the increase in adipocytokine expression in obese adults is mediated by DNA hypomethylation and that DNA hypomethylation is a promising target to prevent obesity-associated inflammation and vascular dysfunction. The flexible modifiable nature of DNA methylation makes it a perfect target for lifestyle interventions such as physical activity and weight loss. Thus, the investigators propose that aerobic exercise training and weight loss following Bariatric surgery will reverse DNA hypomethylation and improve vascular function in obese subjects. This hypothesis will be tested by (1) Investigating abnormal DNA methylation patterns of adipocytokines in fat tissues from obese adults between the age of 18 and 50 compared to non-obese subjects; (2) Test the effectiveness of 12-week aerobic exercise training on reversing DNA hypomethylation and improving vascular function in obese adults; and (3) Examine the effectiveness of weight loss surgery on DNA methylation and vascular function. The proposed studies will improve the understanding of the epigenetic underpinning of obesity-related vascular dysfunction, identify novel therapeutic targets for improving vascular function in obese adults, and provide an evidence for the positive effects of aerobic exercise training and weight loss on the prevention and treatment of obesity-associated cardiovascular disease. These studies will have a positive impact on improving the prevention and therapeutic management of obesity-related cardiovascular morbidities that affect millions of people worldwide.