A history of obesity leaves an inflammatory fingerprint in liver and adipose tissue [Liver]

Dieting is a popular yet often ineffective way to lower body weight, as the majority of people regain most of their pre-dieting weights in a relatively short time. The underlying molecular mechanisms driving weight regain and the increased risk for metabolic disease are still incompletely understood. Here we investigate the molecular alterations inherited from a history of obesity. In our model, male HFD fed obese C57BL/6J mice, were switched to a low caloric chow diet, resulting in a decline of body weight to that of lean mice. Within seven weeks after diet switch, most obesity associated phenotypes, such as body mass, glucose intolerance and blood metabolite levels were reversed. However, hepatic inflammation, hepatic steatosis as well as hypertrophy and inflammation of perigonadal, but not subcutaneous, adipocytes persisted in formerly obese mice. Transcriptional profiling of liver and perigonadal fat revealed an upregulation of pathways associated with immune function and cellularity. Thus, we show that weight reduction leaves signs of inflammation in liver and perigonadal fat, indicating that persisting proinflammatory signals in liver and adipose tissue could contribute to an increased risk of formerly obese subjects to develop the metabolic syndrome upon recurring weight gain.

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Fischer IP, Irmler M, Meyer CW, Sachs SJ, Neff F, Hrabě de Angelis M, Beckers J, Tschöp MH, Hofmann SM, Ussar S