Abstract 262: Circulating Exosomes from PAD Patients Modulate Vascular Repair and Inflammation

Abstract

Objectives: Peripheral arterial disease (PAD) is a chronic disease characterized by inflammation. Recent work suggests that circulating exosomes may contribute to vascular injury and remodeling. We hypothesize that exosomes from PAD subjects negatively modulate vascular repair via miRNA and bioactive lipid mediators (LM). Methods: Exosomes (particle size 30-100nm) were isolated from plasma of healthy (n=6) and PAD (n=6) subjects. Exosome miRNA was isolated and assessed by qPCR. Targeted metabolo-lipidomics was performed by liquid-chromatography-tandem mass spectrometry. VSMC and EC migration were assessed via scratch assay. Monocyte-derived macrophage gene expression after exposure to exosomes was assessed via RT-qPCR. Results: Compared to healthy subjects, exosomes from PAD subjects contained lower levels of pro-angiogenic miR-126 and miR-210 (25.2±6.4 vs 8.3±1.7, p<0.05 and 0.29±0.07 vs 0.08±0.02, p<0.05, respectively). Exosomes contained arachidonic acid, eicosapentaenoic acid and docosapentanoic acid, as well as both pro-inflammatory and pro-resolving bioactive LMs and their pathway markers, including prostaglandins, leukotrienes, lipoxins, resolvins (D- and E-series) and maresins. By principle component analysis, exosome LM profiles differed significantly between healthy and PAD subjects. Exosomes from PAD subjects increased VSMC migration (1.5±.09-fold vs 1.0±.09-fold wound closure, p<0.005) and decreased EC migration (1.5±.04-fold vs. 1.8±.06-fold wound closure, p<0.005) compared to healthy controls. Both PAD and healthy exosomes increased MDM expression of pro-inflammatory genes TNF-α and MCP-1. Conclusion: Plasma-derived exosomes from PAD patients contain an altered profile of vascular-active miRNA and LMs and confer effects on VSMCs and ECs that may impair vessel remodeling. We describe the first known evidence that plasma exosomes contain pro-resolving LMs. Collectively these data suggest that circulating exosome-based signaling may modulate vascular inflammation and repair in PAD patients.