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Gut. 2007 Apr;56(4):560-4. Epub 2006 Jul 19.

NAD(P)H oxidase modulates angiogenesis and the development of portosystemic collaterals and splanchnic hyperaemia in portal hypertensive rats.

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  • 1Hepatic Hemodynamic Laboratory, Liver Unit, Hospital Clinic, Institut d'Investigacions, Biomediques August Pi i Sunyer, University of Barcelona, Barcelona, Spain.

Abstract

BACKGROUND:

Recent studies have shown the presence of vascular endothelial growth factor (VEGF)-dependent splanchnic angiogenesis in experimental models of portal hypertension, and the role of such neovascularisation on the development of both portosystemic collaterals and hyperdynamic splanchnic circulation. However, the mechanisms modulating angiogenesis in portal hypertension are unknown. Experimental evidence indicates that NAD(P)H oxidase is required for VEGF-induced angiogenesis. Interestingly, we have recently shown that splanchnic NAD(P)H oxidase activity is significantly increased in portal hypertensive rats. Therefore, it could be possible that activated NAD(P)H oxidases modulate angiogenesis in portal hypertension.

AIM:

To determine the effects of chronic NAD(P)H oxidase inhibition on angiogenesis and splanchnic haemodynamics in portal hypertensive rats.

METHODS:

Partial portal vein-ligated and sham-operated rats were treated with the NAD(P)H oxidase inhibitor apocynin, or with vehicle for 5 days. Then, the expression of angiogenesis markers (western blotting), the formation of portosystemic collaterals (radioactive microspheres) and the production of superoxide anion (lucigenin-enhanced chemiluminescence) were determined. Mean arterial pressure, portal pressure, and superior mesenteric arterial blood flow and resistance were also measured.

RESULTS:

In portal hypertensive rats, NAD(P)H oxidase blockade significantly decreased portosystemic collateral formation, and superior mesenteric arterial flow. It also reduced the splanchnic expression of VEGF, VEGF receptor-2 and CD31, and attenuated the increased production of superoxide, compared with vehicle.

CONCLUSIONS:

NAD(P)H oxidase plays an important role in experimental portal hypertension, modulating splanchnic angiogenesis, the formation of portosystemic collaterals and the development of splanchnic hyperdynamic circulation. These results suggest that NAD(P)H oxidase may represent a new target in the treatment of portal hypertension.

PMID:
16854998
PMCID:
PMC1856851
DOI:
10.1136/gut.2005.088013
[PubMed - indexed for MEDLINE]
Free PMC Article
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