In vivo gene transfer of endothelial nitric oxide synthase decreases portal pressure in anaesthetised carbon tetrachloride cirrhotic rats.
BACKGROUND
Portal hypertension in cirrhosis results from enhanced intrahepatic resistance to an augmented inflow. The former is partly due to an imbalance between intrahepatic vasoconstriction and vasodilatation. Enhanced endothelin-1 and decreased activity of hepatic constitutive endothelial nitric oxide synthase (NOS 3) was reported in carbon tetrachloride (CCl(4)) cirrhotic rat liver.


OBJECTIVE
To study whether an increase in hepatic NOS 3 could be obtained in the CCl(4) cirrhotic rat liver by in vivo cDNA transfer and to investigate a possible effect on portal pressure.


METHODS
Hepatic NOS 3 immunohistochemistry and western blotting were used to measure the amount of NOS 3 protein. Recombinant adenovirus, carrying cDNA encoding human NOS 3, was injected into the portal vein of CCl(4) cirrhotic rats. Cirrhotic controls received carrier buffer, naked adenovirus, or adenovirus carrying the lac Z gene.


RESULTS
NOS 3 immunoreactivity and amount of protein (western blotting) were significantly decreased in CCl(4) cirrhotic livers. Following cDNA transfer, NOS 3 expression and the amount of protein were partially restored. Portal pressure was 11.4 (1.6) mm Hg in untreated cirrhotic (n=9) and 11.8 (0.6) in lac Z transfected (n=4) cirrhotic rats but was reduced to 7.8 (1.0) mm Hg (n=9) five days after NOS 3 cDNA transfer. No changes were observed in systemic haemodynamics, in liver tests or urinary nitrates, or in NOS 3 expression in lung or kidney, indicating a highly selective transfer.


CONCLUSIONS
NOS 3 cDNA transfer to cirrhotic rat liver is feasible and the increase in hepatic NOS 3 leads to a marked decrease in portal hypertension without systemic effects. These data indicate a major haemodynamic role of intrahepatic NOS 3 in the pathogenesis of portal hypertension in CCl(4) cirrhosis.
Van de Casteele
M
M
Laboratory of Hepatology, University Hospital Gasthuisberg, Leuven, B-3000 Leuven, Belgium.
Omasta
A
A
Janssens
S
S
Roskams
T
T
Desmet
V
V
Nevens
F
F
Fevery
J
J
D000818:Animals; D026481:Blotting, Far-Western; D002251:Carbon Tetrachloride; D004730:Endothelium, Vascular / Q000201:enzymology* / Q000503:physiopathology; D018014:Gene Transfer Techniques; D008099:Liver / Q000201:enzymology / Q000503:physiopathology; D008106:Liver Cirrhosis, Experimental / Q000201:enzymology / Q000235:genetics / Q000503:physiopathology*; D008297:Male; D019001:Nitric Oxide Synthase / Q000235:genetics*; D017082:Portal Pressure / Q000235:genetics / Q000502:physiology*; D051381:Rats; D017208:Rats, Wistar
D002251:Carbon Tetrachloride; D019001:Nitric Oxide Synthase