MO050MESENCHYMAL STEM CELL-DERIVED EXTRACELLULAR VESICLES ATTENUATE RENAL INJURY IN SWINE METABOLIC SYNDROME AND RENOVASCULAR DISEASE

Abstract

Introduction and Aims: Coexisting metabolic syndrome (MetS) and renal artery stenosis (RAS) intensify tissue injury and interfere with its recovery, underscoring the need for effective interventions to preserve the post-stenotic kidney in subjects with MetS. Mesenchymal stem/stromal cells (MSCs) have distinct capability to restore renal structure, but may raise safety concerns. MSC-derived membrane extracellular vesicles (EVs) emerged as a novel non-cellular alternative, yet their mechanisms of action remain unknown. Using a swine model of MetS and RAS we tested the hypothesis that EVs attenuate renal injury, and that this capacity is mediated by their cargo of pro-angiogenic and anti-inflammatory genes. Methods: MetS pigs were studied after 16 weeks of RAS untreated or treated 4 weeks earlier with a single intra-renal delivery of labeled EVs harvested from adipose tissue-derived autologous MSCs (2.5x10-5/Kg). Lean and MetS Sham served as controls (n=7 each). Single-kidney renal blood flow (RBF) and glomerular filtration rate (GFR) were studied in-vivo by multidetector CT, and renal angiogenesis, inflammation, and fibrosis ex-vivo. EVs were collected by ultracentrifugation and characterized based on the expression of EV and MSC markers using flow cytometry. Next-generation mRNA sequencing was performed to identify genes selectively enriched in EVs compared to their parents MCSs (fold change>1.4, p<0.05). Functional annotation clustering analysis was performed to identify cellular pathways regulated by genes enriched in EVs. Results: EVs were enriched with pro-angiogenic (e.g. vascular endothelial growth factor-A and C) and anti-inflammatory (e.g. interleukin-13 receptor, alpha-1) genes. EVs were detected in the stenotic-kidney 4 weeks after injection (Figure). RBF and GFR fell in MetS+RAS compared to MetS, but were restored in EV-treated pigs (Table). Immunoreactivity of the pro-angiogenic factor Notch-1 was downregulated in MetS +RAS, but restored by EVs. The number of infiltrating inflammatory (M1) macrophages, which was higher in MetS compared to Lean kidneys, further increased in MetS+RAS, but decreased in MetS+RAS+EVs pigs. EVs also attenuated tubulointerstitial fibrosis (trichrome staining). Conclusions: Intra-renal delivery of MSC-derived EVs improves renal structure and function in chronic experimental MetS+RAS, partly mediated by their pro-angiogenic and anti-inflammatory cargo, suggesting that EV-based regenerative strategies might be useful for individuals with MetS+RAS. (Figure Presented).