The MULTISITE Study

The worldwide prevalence of obesity and obesity-associated complications is increasing. A common feature associated with obesity is an increased ectopic and visceral fat inside and around the liver, kidney and pancreas. Ectopic and visceral fat is associated with systemic and local pathologies, including liver disease, pancreas disease, and kidney disease. Current tools for diagnosis of obesity-related morbidities are insufficient, where methods either have low diagnostic accuracy, are too expensive, or invasive. This limits their use for patient care. Thus, there is a need for suitable non-invasive biomarkers for obesity-related complications that allow for screening, risk-stratification, and treatment evaluation of the growing obese population. In this context, extracellular vesicles (EVs) are of particular interest. EVs are small membrane-encapsulated particles released from cells into the blood circulation, and each EV can be considered a micro-biopsy of one single cell. It is proposed that differences in EV number and phenotype can function as potential biomarkers for obesity-related complications. Early intervention against obesity and related complications minimizes future diseases. As obesity and its complications are associated with a positive energy balance, the best intervention is increased energy expenditure and/or decreased energy intake , leading to weight loss. Intervention against obesity requires permanent lifestyle changes, which can be helped by e.g., individualised diet and exercise plans, surgery, and counselling. The aims of this project are thus, 1) to investigate visceral and ectopic fat and its associated complications with focus on NAFLD, NAFPD and fatty kidney. 2) investigate whether EVs can function as potential non-invasive biomarkers for any of these conditions, and 3) investigate if a lifestyle intervention decreases liver visceral and ectopic fat, and whether this improvement is reflected by an improvement of NAFLD and changes in EV phenotypes. The specific aims are as follows: 1. Investigate potential correlations and relationships between obesity and organ-specific complications, including NAFLD, NAFPD and fatty kidney; 2. Compare obese participants with lean control subjects, and investigate whether organ-specific EVs can be used as a biomarker for early detection of any of the above-mentioned conditions/states; 3. Investigate how and if a lifestyle-induced weight-loss intervention decreases liver fat and improve NAFLD. Furthermore, investigate if weight changes and the resulting improvement of NAFLD are accompanied by changes in liver-specific EV phenotypes.