Effects of Liraglutide on Epicardial Fat Pro-Inflammatory Genes in Type 2 Diabetes and Coronary Artery Disease

Epicardial adipose tissue (EAT) is the visceral fat of the heart. EAT could locally affect the coronary arteries through local secretion of pro-inflammatory cytokines. EAT plays a role in the development of the coronary artery disease (CAD). EAT is a highly enriched with genes involved in inflammation. Given its rapid metabolism and simple measurability, as first developed by Iacobellis, EAT serves as target for medications targeting the fat. Glucagon-like peptide-1 agonists (GLP-1A) are anti-diabetic medications with recently suggested cardio-protective properties. Liraglutide, a GLP-1A, has recently shown to reduce the cardiovascular risk. Iacobellis'group found that EAT thickness decreased by an unprecedented 36% after 12 weeks of treatment with liraglutide. Remarkably, Iacobellis'group found for the first time that human EAT express GLP-1 Receptor (GLP-1R). GLP-1A effects may be therefore visceral fat specific and target EAT. Based on these preliminary data, we hypothesize that treatment with liraglutide will significantly and rapidly reduce EAT inflammation. Decreased EAT inflammation can reduce the burden of the coronary plaques. We will test our hypothesis in a 12-week randomized, double-blind, placebo-controlled, interventional study in 40 patients with type 2 diabetes mellitus (T2DM), and CAD, with an acceptable glycemic control on their current diabetes regimen who require elective coronary artery bypass graft (CABG) regardless of their participation in the study. A minimum time frame of 3-week treatment will be considered to detect significant changes in the study endpoints. Inclusion criteria for body fat markers will rule out the confounding effect of different body fast distribution at baseline. Study subjects will be randomized in two groups of 20 patients to receive additional liraglutide or to remain on current treatment/ placebo prior to cardiac surgery. CAD subjects not allocated to liraglutide will be started on a supervised low-calorie diet (LCD) to achieve approximately 5% of weight loss after from a minimum of 3 weeks up to 12 weeks to avoid the confounding effect of weight loss on the study outcomes. Fat samples will be collected during cardiac surgery after up to 12 weeks of treatment either with liraglutide or placebo and processed for analysis of mRNA and protein expression of EAT and SAT inflammatory genes such as Tumor Necrosis Factor-alpha (TNF-α) and Interleukin 6 (IL-6), and GLP-1R.

This will be a double-blind, parallel group, placebo controlled study. The method of allocation generation will be a computerized random-number generator. The sequence will be generated by the process of restricted randomization. Computer-based randomization process will be managed by the UM Research pharmacy.