Intrarenal Delivery of Mesenchymal Stem Cells and Endothelial Progenitor Cells Attenuates Hypertensive Cardiomyopathy in Experimental Renovascular Hypertension

Abstract

Renovascular hypertension (RVH) leads to left ventricular (LV) hypertrophy and diastolic dysfunction, associated with increased cardiovascular mortality. Intrarenal delivery of endothelial progenitor cells (EPCs) and mesenchymal stem cells (MSCs) improves kidney function in porcine RVH, and the potent anti-inflammatory properties of MSCs may serve to blunt inflammatory mediators in the cardiorenal axis. However, their relative efficacy in attenuating cardiac injury and dysfunction remains unknown. This study tested the hypothesis that the cardioprotective effect of EPCs and MSCs delivered into the stenotic kidney in experimental RVH are comparable. Pigs (n = 7 per group) were studied after 10 weeks of RVH or control untreated or treated with a single intrarenal infusion of autologous EPCs or MSCs 4 weeks earlier. Cardiac and renal function (fast CT) and stenotic kidney release of inflammatory mediators (ELISA) were assessed in vivo, and myocardial inflammation, remodeling, and fibrosis ex vivo. After 10 weeks of RVH, blood pressure was not altered in cell-treated groups, yet stenotic kidney glomerular filtration rate (GFR), blunted in RVH, improved in RVH + EPC, and normalized in RVH + MSCs. Stenotic kidney release of monocyte chemoattractant protein (MCP)-1 and its myocardial expression were elevated in RVH + EPC, but normalized only in RVH + MSC pigs. RVH-induced LV hypertrophy was normalized in both EPC- and MSC-treated pigs, while diastolic function (E/A ratio) was restored to normal levels exclusively in RVH + MSCs. RVH-induced myocardial fibrosis and collagen deposition decreased in RVH + EPCs but further decreased in RVH + MSC-treated pigs. Intrarenal delivery of EPCs or MSCs attenuates RVH-induced myocardial injury, yet MSCs restore diastolic function more effectively than EPCs, possibly by greater improvement in renal function or reduction of MCP-1 release from the stenotic kidney. These observations suggest a therapeutic potential for EPCs and MSCs in preserving the myocardium in chronic experimental RVH.

Figures

Figure 1

Schematic of the experimental protocol. RVH: renovascular hypertension, MSCs: mesenchymal stem cells, EPCs: endothelial progenitor cells.

Figure 2

A: Fluorescence-activated cell sorting analysis performed on in-vitro-cultured endothelial progenitor cells (EPCs) and mesenchymal stem cells (MSCs) to determine cell surface expression of CD133, kinase-insert domain receptor (KDR), CD44, and CD90. B: Representative immunofluorescence staining (40×) of CM-Dil (red) EPCs and MSCs in the stenotic-kidney, contralateral kidney (CLK), and left-ventricle sections. Cytokeratin, phaseolus vulgaris erythroagglutinin (PHA-E), peanut agglutinin (PA), CD31, and proliferating cell nuclear antigen (PCNA): Green, DAPI: Blue.

Figure 3

Stenotic-kidney net release of interferon (IF)-γ (A), tumor necrosis-factor (TNF)-α (B), interleukin (IL)-10 (C), and monocyte-chemoattractant-protein (MCP)-1 (D) in normal, normal+EPC, normal+MSC, RVH, RVH+EPC, and RVH+MSC. *p

Figure 4

Myocardium double immunofluorescence staining of connexin-43 (green) and the inflammatory mediators (red): interferon (IF)-γ (A), tumor necrosis-factor (TNF)-α (B), interleukin (IL)-10 (C), and monocyte-chemoattractant-protein (MCP)-1 (D) and their quantification. Blue: DAPI. *p≤0.05 vs. Normal; #p

Figure 5

A: Myocyte cross-sectional area (H&E, 40×) and its quantification. B: Representative immunostaining and quantification of Sirius red and trichrome (40×). *p

Figure 6

A: Renal blood flow (RBF), and glomerular filtration rate (GFR) in the contralateral kidney (CLK) of NORMAL, NORMAL+EPC, NORMAL+MSC, RVH, RVH+EPC, and RVH+MSC pigs. B: Representative images of CLK tubulo-interstitial trichrome staining (left) and quantification of tubulo-interstitial fibrosis (right). *p