Abstract 15480: Liraglutide Inhibits Atherosclerotic Plaque Progression in Rabbits Through the Downregulation of Multiple Inflammatory and Metabolic Pathways

Background: Liraglutide, a GLP-1- receptor agonists approved for the treatment of type 2 diabetes and obesity confers a lower CVD mortality. However, mechanisms underlying this finding remain unknown, particularly in normoglycemic subjects. We investigated the effects of liraglutide on the progression and pathobiology of atherosclerosis using multimodal intravascular imaging in rabbits. Methods: Rabbits atherosclerosis (N=16) were induced by balloon injury of the abdominal aorta and cholesterol feeding for 6 weeks. Then, rabbits were imaged with intravascular ultrasound (IVUS) and near-infrared fluorescence optical coherence tomography (NIRF-OCT) for the analysis of plaque burden and plaque inflammation (ProSense VM110 NIRF agent, 4 mg/kg/iv) respectively. Next, rabbits were randomized into: Control (n=8) or liraglutide (n=8, 0.1 mg/kg/day) groups. Imaging was repeated after 4 weeks, followed by histopathology and RNA analysis. On per-slice basis (every 0.4 mm) of IVUS imaging, the percent atheroma volume (PAV) was measured across the 40 mm balloon injured area. Atheroma progression was quantified as the ΔPAV between 6 and 10 weeks. Results: IVUS analyses (3200 slices/16 rabbits) revealed that liraglutide significantly reduced plaque progression (ΔPAV, 1.5% [0.2-2.8] vs. 9.3% [6.7-13.0] control, p=0.05). In vivo distance-corrected VM110 cathepsin inflammatory plaque activity was similar (ΔNIRF average plaque 25.2 [-9.8- 62] vs. 22.6 [3.9- 52.5] nM control, p=0.72). Plaques from liraglutide-treated animals however exhibited fewer RAM11+ macrophages (21.3±11.4 vs. control 30.9±16.7 macrophages/section, p=0.01) stry. Both plaques showed similar αSMA (45.2±6.7% vs 52.4±1.2% αSMA+ area/section, p=0.327). Liraglutide decreased inflammatory RNA transcripts (IL-6 and TNF-α), and RNA-seq transcriptomic analysis revealed that liraglutide altered inflammatory and metabolic pathways (as CRP, CYP3A6, Apo-A4 and FMO3). Blood glucose was normal and similar between groups (p>0.05). Conclusion: Liraglutide suppresses in vivo atherosclerotic plaque progression and plaque macrophage expression in normoglycemic rabbits. Further investigation of its plaque stabilizing effects in subjects with and without diabetes is warranted.