418 Activation of the Glucagon-Like Peptide-1 Pathway in Obese Pre-Diabetic Individuals Improves Endothelial Function Independently of Weight Loss

Abstract

OBJECTIVES/GOALS: We aimed to determine if GLP-1 receptor agonists exert beneficial effects on surrogate measures of cardiovascular function independently of weight loss. Our objective was to compare the outcomes between GLP-1 receptor agonist treatment versus a similar drug without cardiovascular benefit versus weight loss through diet alone. METHODS/STUDY POPULATION: We enrolled 88 individuals with obesity (BMI ≥ 30kg/m2) and pre-diabetes and randomized them in a 2:1:1 ratio to 14 weeks of the GLP-1 receptor agonist liraglutide, the dipeptidyl peptidase-4 inhibitor sitagliptin, or hypocaloric diet. Sitagliptin blocks degradation of endogenous GLP-1 but does not cause weight loss or lower adverse cardiovascular outcomes. Treatment was double-blinded and placebo-controlled for drug, and unblinded for diet. Primary endpoints were flow-mediated dilation (FMD) to assess endothelial vasodilatory function, and plasminogen activator inhibitor-1 (PAI-1) to assess endothelial fibrinolytic function. We used a general linear model for each outcome and included gender as a covariate for FMD. Baseline characteristics were similar. Mean age was 50, with 32% men and 13% black. RESULTS/ANTICIPATED RESULTS: At 14 weeks, diet and liraglutide caused weight loss (diet -4.3 ± 3.2 kg, P<0.01; liraglutide -2.7 ± 3.2, P<0.01), while sitagliptin did not (-0.7 ± 2.0, P=0.17). Diet did not improve FMD at 14 weeks compared to baseline (+0.9%, 95% CI [-1.5, 3.3], P=0.46). FMD tended to increase after liraglutide and sitagliptin but was not significant (liraglutide +1.2 [-0.3, 2.8], P=0.12; sitagliptin +1.6 [-0.6, 3.8], P=0.15). Given that liraglutide and sitagliptin work through the same GLP-1 pathway, we combined the liraglutide and sitagliptin groups for overall effect on FMD, which was significantly improved from baseline (+1.4 [0.1, 2.8], P=0.04). Diet and liraglutide improved PAI-1 at 14 weeks (diet -4.4U/mL, [-8.5, -0.2], P=0.04; liraglutide -3.4 [-6.0, -0.7], P=0.01), while sitagliptin did not (-1.4 [-5.1, 2.3], P=0.46). DISCUSSION/SIGNIFICANCE: Activation of the GLP-1 pathway by liraglutide or sitagliptin improves FMD independent of weight loss, while PAI-1 improvement is weight-loss dependent and is only seen after liraglutide or diet. Our study suggests the cardiovascular benefit of liraglutide may be due to combined improvements in endothelial vasodilatory and fibrinolytic function.