Antioxidant intervention prevents renal neovascularization in hypercholesterolemic pigs.
Experimental hypercholesterolemia (HC) may lead to microvascular neovascularization, but the underlying pathogenic mechanism remains unclear. We tested the hypothesis that HC-induced intra-renal neovascularization is associated with inflammation and increased oxidative stress, and would be prevented by chronic antioxidant intervention. Kidneys were excised from pigs after a 12-wk normal (n = 10) or HC diet (n = 8), or HC diet supplemented daily with antioxidant vitamins C (1 g) and E (100 IU/kg) (HC + vitamins, n = 7). Renal cortical samples were then scanned three dimensionally with micro-computed tomography, and microvessels were counted in situ. Blood and tissue samples were removed for measurements of superoxide dismutase (SOD) activity, protein expression of the NADP(H)-oxidase subunits gp91phox, p47phox, and p67phox, vascular endothelial growth factor (VEGF) levels and mRNA, VEGF receptors (Flt-1 and Flk-1), the proinflammatory transcription factor NFkappaB, and the oxidized LDL receptor LOX-1. Microvascular spatial density was significantly elevated in HC compared with normal kidneys but preserved in HC + vitamins. Expression of gp91phox and p67phox was decreased in HC pigs after antioxidant intervention, and SOD improved. The increased renal expression of VEGF and Flk-1 in HC was blunted in HC + vitamins, as were the significant increases in LOX-1, NFkappaB, and interstitial fibrosis. This study shows that renal cortical neovascularization elicited by diet-induced HC is associated with renal inflammation, fibrosis, and upregulation of VEGF and its receptor Flk-1, likely mediated by increased endogenous oxidative stress. Chronic antioxidant supplementation may preserve the kidney in HC.
Chade
Alejandro R
AR
Department of Internal Medicine (Division of Nephrology and Hypertension), Mayo Clinic, Rochester, Minnesota 55905, USA.
Bentley
Michael D
MD
Zhu
Xiangyang
X
Rodriguez-Porcel
Martin
M
Niemeyer
Sara
S
Amores-Arriaga
Beatriz
B
Napoli
Claudio
C
Ritman
Erik L
EL
Lerman
Amir
A
Lerman
Lilach O
LO
D000818:Animals; D000975:Antioxidants / Q000378:metabolism / Q000494:pharmacology; D001205:Ascorbic Acid / Q000378:metabolism; D015153:Blotting, Western; D001835:Body Weight; D018076:DNA, Complementary / Q000378:metabolism; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D005355:Fibrosis; D006937:Hypercholesterolemia / Q000378:metabolism*; D007091:Image Processing, Computer-Assisted; D007249:Inflammation; D007668:Kidney / Q000098:blood supply* / Q000201:enzymology / Q000473:pathology*; D008562:Membrane Glycoproteins / Q000378:metabolism; D008833:Microcirculation; D000074662:NADPH Oxidase 2; D019255:NADPH Oxidases / Q000378:metabolism; D016328:NF-kappa B / Q000378:metabolism; D009389:Neovascularization, Pathologic; D010084:Oxidation-Reduction; D010750:Phosphoproteins / Q000378:metabolism; D012313:RNA / Q000378:metabolism; D012333:RNA, Messenger / Q000378:metabolism; D040262:Receptors, Vascular Endothelial Growth Factor / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013482:Superoxide Dismutase / Q000378:metabolism; D013552:Swine; D014057:Tomography, X-Ray Computed; D042461:Vascular Endothelial Growth Factor A / Q000378:metabolism
D000975:Antioxidants; D018076:DNA, Complementary; D008562:Membrane Glycoproteins; D016328:NF-kappa B; D010750:Phosphoproteins; D012333:RNA, Messenger; D042461:Vascular Endothelial Growth Factor A; C079789:neutrophil cytosol factor 67K; D012313:RNA; D013482:Superoxide Dismutase; C056558:CYBB protein, human; D000074662:NADPH Oxidase 2; D019255:NADPH Oxidases; C060505:neutrophil cytosolic factor 1; D040262:Receptors, Vascular Endothelial Growth Factor; D001205:Ascorbic Acid