Pericardial Fluid Extracellular Vesicles Enhance Angiogenesis and Blunt Cardiac Fibrosis in Coronary Disease.

BACKGROUND:To date, we have lacked an understanding of how coronary artery disease (CAD) affects the extracellular vesicle (EV) profile of human pericardial fluid (PF) and there is a paucity of data querying whether PF-derived EVs have functional benefits. This study characterizes PF-derived EVs and assesses their impact on angiogenesis in vitro and in vivo. METHODS:PF was collected from patients with and without CAD. PF-derived EVs of different sizes were isolated and characterized using microfluidic resistive pulse sensing. Human coronary artery endothelial cells (HCAECs) were exposed to EVs. Uptake of EVs by HCAECs and their impact on cell proliferation was evaluated. HCAECs were analyzed for their migratory and angiogenic properties. The in vivo effects of PF-derived EVs were assessed using murine ischemia models. To elucidate putative mechanisms, proteomic analysis was performed followed by in silico pathway analysis and functional validation. RESULTS:Small and medium-sized EVs (sEV and mEV, respectively) were isolated from PF. HCAECs exposed to sEVs isolated from CAD patients exhibited a significant increase in proliferations, wound closure, and tube formation. Injection of sEVs isolated from the PF of patients with CAD into pericardial cavity of MI mice reduced cardiac fibrosis and improved cardiac function. Differential protein expression implicated key pathways in angiogenesis, apoptosis mitigation, and fibrosis as protective effects of PF-sEVs. CONCLUSION:We identify that PF-derived EVs exert cardioprotective effects by promoting angiogenesis and reducing fibrosis. Future studies should evaluate whether our findings can be recapitulated in a large animal model and a pilot clinical trial.