Abdominal Obesity, Cardiovascular Inflammation, and Effects of a Growth Hormone Releasing Hormone Analogue to Reduce Inflammation

Obesity is strongly associated with risk of cardiovascular disease (CVD). Data increasingly suggest that visceral adipose tissue (VAT) accumulation -- or increased abdominal fat -- is particularly deleterious to cardiovascular health, but further study is needed to test this idea. Increased abdominal fat may also be associated with lower secretion of a hormone called growth hormone (GH), which helps the body burn fat. The current study aims to carefully characterize relationships between abdominal fat and CVD. In addition, by using a medication called growth hormone releasing hormone, which is a strategy to reduce abdominal fat, the investigators will test the hypothesis that abdominal fat contributes uniquely to increased arterial inflammation.

In the first part of this study, the investigators will investigate both lean (healthy weight) individuals and individuals with increased abdominal fat. The investigators will study their body composition, cardiovascular risk measures, insulin sensitivity, and growth hormone dynamics, with the hypothesis that abdominal fat, independent of general obesity, will be strongly associated with arterial wall thickening and atherosclerotic inflammation. The investigators will assess arterial wall thickness, plaque morphology, and atherosclerotic inflammation, and the investigators will determine associations between these variables and regional fat accumulation, with particular attention to abdominal fat.

The second, treatment part of the study will be only for individuals with increased abdominal fat who are found to have low growth hormone secretion. In that part of the study, the investigators will test the effects of a growth hormone releasing hormone (GHRH) analogue to reduce abdominal fat and, consequently, reduce arterial inflammation. The investigators hypothesize that abdominal fat reduction, independent of changes in growth hormone, will reduce arterial inflammation and arterial wall thickness.