Project 452259

With obesity, expansion of fat tissue in different depots results in fat that does not work properly. When fat does not work properly, the fat contributes to the development of metabolic diseases such as diabetes and heart disease. Though the fat around the stomach receives a lot of bad press, research shows that the fat in the legs might be just as important when it comes to disease risk. Weight loss by bariatric surgery helps improve or cure metabolic disease. Since the majority of weight loss after bariatric surgery is from the fat located underneath our skin, it follows that the health of this fat depot may be important in disease. Losses of fat around the legs may be an especially key factor because when bariatric surgery patients do not lose much fat around their legs, the metabolic diseases they have does not improve. This study aims to determine how the fat tissue under the skin of the legs compares to that of the stomach in people who are healthy, those with obesity, and those with obesity and diabetes. We also want to know if unhealthy aspects of this fat can become healthy after weight loss. We will compare the fat in the tummy and thighs for: 1) how fat cell behave and interact with muscle cells, 2) what is happening inside the fat cells, 3) the signals that they release. In this study, we specifically want to compare fat under the skin around the belly and in the legs because: 1) we know very little about this fat, 2) most (80%) of the fat in the body is stored under the skin so fat under the skin that does not work properly could have a large impact on disease development, 3) fat is more likely to collect in and around the organs when the fat under the skin does not 'work' right. Understanding how fat under the skin differs in healthy and unhealthy individuals is of great interest as it is the first step to improving health in those with obesity.