Abstract:
Obesity has become a major epidemic, not just in the US, but in many other industrialized nations around the world. Obesity has risen due to the natural conflict between availability of calorie-rich foods and energy efficient metabolisms naturally selected for tens of thousands of years in the past. Unfortunately, obesity is detrimental to health as it is associated with a number of chronic conditions including type II diabetes and liver disease. This study explores the effects of the accumulation of visceral adipose on systemic inflammation as measured within adipose itself, in circulation, and in the liver parenchyma as determined by histopathology. The cross-talk between omental deposits of adipose and liver was analyzed by profiling serum cytokine levels, adipose gene expression, and liver biopsy histopathology for 241 morbidly obese patients undergoing bariatric surgery. We showed that the levels of pro-inflammatory cytokines increase in parallel with an increase in the severity of liver disease, while the levels of anti-inflammatory factors decrease. Additionally, we studied expression levels of genes that define the differentiation and activity of brown adipose cells within visceral adipose collected from the same cohort of morbidly obese subjects. We showed that expression levels for genes specific for brown adipose tissue decrease proportionally to the increase in both serum and histological indicators of systemic inflammation. Importantly, our study is the first to provide evidence that scattered brown adipocytes may be present in visceral adipose of morbidly obese subjects and that their numbers or activity levels may diminish with an increase in systemic inflammation associated with obesity and metabolic syndrome.
