Adipose Tissue Dysfunction in Type 2 Diabetes and Its Reversibility by Bariatric Surgery

Overview

ABSTRACT Background: Insulin resistance (IR) plays a major role in the pathogenesis of type 2 diabetes (T2D). Adipose tissue (AT) dysfunction leading to systemic low-grade inflammation and ectopic lipid deposition plays an important role in obesity-induced IR, but its role in T2D pathogenesis and to what extent insulin-sensitizing interventions can reverse AT dysfunction remain to be clarified. Hypothesis/aims: To test the hypotheses 1) that T2D is associated with exaggerated AT dysfunction compared with obesity alone, 2) that increased insulin sensitivity and remission of T2D after bariatric surgery is in part explained by improved AT function Research plan: Novel markers of exaggerated AT dysfunction will be identified and studied together with known markers of AT dysfunction in patients with T2D compared with non-diabetic obese and lean individuals. Then the effects of bariatric surgery on all these markers of AT dysfunction in obesity and T2D will be studied. Adipose tissue and skeletal muscle biopsies and blood samples will be used for 1) next generation RNA sequencing, 2) targeted analysis of mRNA and protein content/activities, 3) metabolomics, 4) morphological analysis and 5) analysis of adipokines/myokines. Abnormalities in T2D and changes in response to bariatric surgery will be related to substrate metabolism, insulin sensitivity and secretion and insulin signalling in muscle. Perspectives: This project provides novel insight into the role of AT dysfunction in T2D pathogenesis in humans and the potential of bariatric surgery to reverse AT dysfunction and improve insulin sensitivity. We ultimately expect that this will help us to identify novel pharmaceutical targets for the treatment of IR.