Antioxidant intervention prevents renal neovascularization in hypercholesterolemic pigs

J Am Soc Nephrol. 2004 Jul;15(7):1816-25. doi: 10.1097/01.asn.0000130428.85603.6b.

Abstract

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.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Animals
  • Antioxidants / metabolism
  • Antioxidants / pharmacology
  • Ascorbic Acid / metabolism
  • Blotting, Western
  • Body Weight
  • DNA, Complementary / metabolism
  • Enzyme-Linked Immunosorbent Assay
  • Female
  • Fibrosis
  • Hypercholesterolemia / metabolism*
  • Image Processing, Computer-Assisted
  • Inflammation
  • Kidney / blood supply*
  • Kidney / enzymology
  • Kidney / pathology*
  • Membrane Glycoproteins / metabolism
  • Microcirculation
  • NADPH Oxidase 2
  • NADPH Oxidases / metabolism
  • NF-kappa B / metabolism
  • Neovascularization, Pathologic*
  • Oxidation-Reduction
  • Phosphoproteins / metabolism
  • RNA / metabolism
  • RNA, Messenger / metabolism
  • Receptors, Vascular Endothelial Growth Factor / metabolism
  • Reverse Transcriptase Polymerase Chain Reaction
  • Superoxide Dismutase / metabolism
  • Swine
  • Tomography, X-Ray Computed
  • Vascular Endothelial Growth Factor A / metabolism

Substances

  • Antioxidants
  • DNA, Complementary
  • Membrane Glycoproteins
  • NF-kappa B
  • Phosphoproteins
  • RNA, Messenger
  • Vascular Endothelial Growth Factor A
  • neutrophil cytosol factor 67K
  • RNA
  • Superoxide Dismutase
  • CYBB protein, human
  • NADPH Oxidase 2
  • NADPH Oxidases
  • neutrophil cytosolic factor 1
  • Receptors, Vascular Endothelial Growth Factor
  • Ascorbic Acid