Adipose tissue-derived mesenchymal stem cells improve revascularization outcomes to restore renal function in swine atherosclerotic renal artery stenosis

Abstract

Reno-protective strategies are needed to improve renal outcomes in patients with atherosclerotic renal artery stenosis (ARAS). Adipose tissue-derived mesenchymal stem cells (MSCs) can promote renal regeneration, but their potential for attenuating cellular injury and restoring kidney repair in ARAS has not been explored. We hypothesized that replenishment of MSC as an adjunct to percutaneous transluminal renal angioplasty (PTRA) would restore renal cellular integrity and improve renal function in ARAS pigs. Four groups of pigs (n = 7 each) were studied after 16 weeks of ARAS, ARAS 4 weeks after PTRA and stenting with or without adjunct intrarenal delivery of MSC (10 × 10(6) cells), and controls. Stenotic kidney blood flow (renal blood flow [RBF]) and glomerular filtration rate (GFR) were measured using multidetector computer tomography (CT). Renal microvascular architecture (micro-CT), fibrosis, inflammation, and oxidative stress were evaluated ex vivo. Four weeks after successful PTRA, mean arterial pressure fell to a similar level in all revascularized groups. Stenotic kidney GFR and RBF remained decreased in ARAS (p = .01 and p = .02) and ARAS + PTRA (p = .02 and p = .03) compared with normal but rose to normal levels in ARAS + PTRA + MSC (p = .34 and p = .46 vs. normal). Interstitial fibrosis, inflammation, microvascular rarefaction, and oxidative stress were attenuated only in PTRA + MSC-treated pigs. A single intrarenal delivery of MSC in conjunction with renal revascularization restored renal hemodynamics and function and decreased inflammation, apoptosis, oxidative stress, microvascular loss, and fibrosis. This study suggests a unique and novel therapeutic potential for MSC in restoring renal function when combined with PTRA in chronic experimental renovascular disease.

Copyright © 2012 AlphaMed Press.

Figures

Figure 1

A: Renal angiography in a pig with atherosclerotic renal artery stenosis (ARAS) before (left) and 4 weeks after (right) revascularization with percutaneous transluminal renal angioplasty (PTRA). B: Mean arterial pressure measured using telemetry decreased after PTRA. C: Single-kidney RBF and GFR were restored in MSC-treated pigs, although RBF response to Ach remained blunted. *p

Figure 2

A: Micro-CT 3D images of the kidney showing improved microvascular architecture in ARAS+PTRA+MSC. Transmural spatial density (B) and its classification by vessel size (C), average vessel diameter (D), and tortuosity (E) of renal cortical microvessels. F: Renal protein expression of vascular endothelial growth factor (VEGF) was downregulated in ARAS and ARAS+PTRA, but improved in ARAS+PTRA+MSC. *p

Figure 3

Oxidative stress declined after PTRA+MSC. A: Renal production of superoxide anion (top), detected by dihydroethidium (40×), and its quantification (bottom). B: Representative immunoblots and renal protein expression of nitrotyrosine (NT) and p47 in Normal, ARAS, ARAS+PTRA, and ARAS+PTRA+MSC. *p

Figure 4

PTRA+MSC decreased renal inflammation. Representative immunostaining (40×) of B-T lymphocytes (CD45+), T-lymphocytes (CD3+), and macrophages (CD163+) (A) and their quantification (B, C, and D). Renal protein expression of TNF-α increased in ARAS and ARAS+PTRA, and tended to decline in ARAS+PTRA+MSC, although it remained higher than normal (E). *p

Figure 5

A: Representative renal trichrome staining (40×) in normal, ARAS, ARAS+PTRA and ARAS+PTRA+MSC pigs. Glomerular and tubulointerstitial fibrosis (B) and glomerular score (C, % of sclerotic glomeruli) decreased after PTRA+MSC. *p

Figure 6

A: Representative Sirius red staining, under polarized light (top) and its quantification (bottom). B: Representative immunoblots and densitometric quantification of TGF-β1. *p