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

• Published in: International Journal of Obesity Vol. 42; no. 3; pp. 507 - 517
• Main Authors: Fischer, I P, Irmler, M, Meyer, C W, Sachs, S J, Neff, F, Hrabě de Angelis, M, Beckers, J, Tschöp, M H, Hofmann, S M, Ussar, S
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 01.03.2018; Nature Publishing Group
• Subjects: 38/61; 38/77; 631/443/319/1642/2037; 631/443/319/1642/393; 64/60; 692/420/256; Adipocytes; Adipose tissue; Adipose Tissue - chemistry; Adipose Tissue - metabolism; Analysis; Animals; Biomarkers - analysis; Body composition; Body mass; Body weight; Body weight gain; Caloric Restriction; Diet; Epidemiology; Fatty liver; Fatty Liver - metabolism; Gene expression; Glucose; Glucose tolerance; Health Promotion and Disease Prevention; High fat diet; Homeostasis; Hypertrophy; Hypocaloric diet; Hypothalamus; Immune response; Inflammation; Inflammation - metabolism; Insulin; Internal Medicine; Intolerance; Leaves; Liver; Liver - chemistry; Liver - metabolism; Male; Medicine; Medicine & Public Health; Metabolic Diseases; Metabolic disorders; Metabolic syndrome; Metabolism; Metabolites; Mice; Mice, Inbred C57BL; Molecular modelling; Nutrient deficiency; Obesity; Obesity - diet therapy; Obesity - metabolism; Original; original-article; Public Health; Risk factors; Transcription; Weight Loss - physiology; Weight reduction
• ISSN: 0307-0565; 1476-5497; 1476-5497
• DOI: 10.1038/ijo.2017.224

Background/Objectives: 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. Methods: In our model, male high-fat diet (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. We measured body composition, as well as metrics of glucose, insulin and lipid homeostasis. This was accompanied by histological and gene expression analysis of adipose tissue and liver to assess adipose tissue inflammation and hepatosteatosis. Moreover, acute hypothalamic response to (re-) exposure to HFD was assessed by qPCR. Results & Conclusions: Within 7 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.