PhD conferral Ioannis G. Lempesis

Keywords: Obesity, body fat distribution, metabolism, inflammation

"Body fat distribution and obesity: a comparison of upper and lower body adipose tissue biology in humans"

Obesity increases the risk of developing cardiometabolic diseases due to adipose tissue (AT) dysfunction and body fat distribution, with abdominal fat accumulation increasing the risk of complications. This thesis investigated the differences between upper and lower body AT biology, focusing on AT blood flow (ATBF), inflammatory signatures, and the oxidative machinery of abdominal (upper body) and femoral (lower body) subcutaneous AT in humans with normal weight or obesity. It also investigated the influence of prolonged exposure to various oxygen levels on the inflammatory phenotype of abdominal and femoral adipocytes. From this research, it was found that it is technically feasible to measure abdominal and femoral intravascular ATBF using percutaneous Doppler ultrasound. Furthermore, we demonstrated distinct inflammatory signatures between abdominal and femoral AT and adipocytes. Moreover, AT oxygen extraction and adipocyte oxygen consumption were lower in abdominal than femoral AT in women with normal weight or obesity. Finally, low physiological oxygen levels decreased gene expression and secretion of pro-inflammatory factors in both abdominal and femoral adipocytes derived from individuals with obesity but not normal weight.

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