Hemodynamic and antifibrotic effects of a selective liver nitric oxide donor V-PYRRO/NO in bile duct ligated rats.

AIM: To assess whether a liver specific nitric oxide (NO) donor (V-PYRRO/NO) would prevent the development of portal hypertension and liver fibrosis in rats with bile duct ligation (BDL). METHODS: Treatment (placebo or V-PYRRO/NO 0.53 micromol/kg per hour) was administered i.v. to rats 2 d before BDL (D-2) and maintained until the day of hemodynamic measurement (D26). Intra-hepatic NO level was estimated by measuring liver cGMP level. Effects of V-PYRRO/NO on liver fibrosis and lipid peroxidation were also assessed. RESULTS: Compared to placebo treatment, V-PYRRO/NO improved splanchnic hemodynamics in BDL rats: portal pressure was significantly reduced by 27% (P<0.0001) and collateral circulation development was almost completely blocked (splenorenal shunt blood flow by 74%, P=0.007). Moreover, V-PYRRO/NO significantly prevented liver fibrosis development in BDL rats (by 30% in hepatic hydroxyproline content and 31% in the area of fibrosis, P<0.0001 respectively), this effect being probably due to a decrease in lipid peroxidation by 44% in the hepatic malondialdehyde level (P=0.007). Interestingly, we observed a significant and expected increase in liver cGMP, without any systemic hemodynamic effects (mean arterial pressure, vascular systemic resistance and cardiac output) in both sham-operated and BDL rats treated with V-PYRRO/NO. This result is in accordance with studies on V-PYRRO/NO metabolism showing a specific release of NO in the liver. CONCLUSION: Continuous administrations of V-PYRRO/NO in BDL rats improved liver fibrosis and splanchnic hemodynamics without any noxious systemic hemo-dynamic effects.

Terlipressin inhibits in vivo aortic iNOS expression induced by lipopolysaccharide in rats with biliary cirrhosis.

In cirrhosis, lipopolysaccharide (LPS, a product of Gram-negative bacteria) in the blood may cause septic shock. LPS-elicited induction of arterial inducible nitric oxide synthase (iNOS) results in nitric oxide (NO)-induced vasodilation, which causes arterial hypotension and hyporeactivity to alpha(1)-adrenergic constrictors. In vitro studies have suggested that vasopressin inhibits iNOS expression in cultured vascular smooth muscle cells exposed to LPS. Thus, the aim of this study was to investigate the effects of terlipressin administration (a vasopressin analog) on in vivo LPS-induced aortic iNOS in rats with cirrhosis. LPS (1 mg/kg, intravenously) was administered followed by the intravenous administration of terlipressin (0.05 mg/kg, intravenously) or placebo 1 hour later. Arterial pressure was measured, and contractions to phenylephrine (an alpha(1)-adrenoceptor agonist), iNOS activity, and iNOS expressions (mRNA and protein) were investigated in isolated aortas. LPS-induced arterial hypotension and aortic hyporeactivity to phenylephrine were abolished in rats that received terlipressin. LPS-induced aortic iNOS activity and expression were suppressed in terlipressin-treated rats. In conclusion, in LPS-challenged rats with cirrhosis, terlipressin administration inhibits in vivo LPS-induced aortic iNOS expression. Terlipressin administration may be a novel approach for the treatment of arterial hypotension and hyporeactivity to alpha(1)-adrenergic constrictors in patients with cirrhosis and septic shock.

Evolution of hypoxemia in patients with severe cirrhosis.

BACKGROUND AND AIM: Hypoxemia is common in patients with cirrhosis but the natural history of this syndrome is unknown. The aim of this study was to follow a series of patients with cirrhosis and to compare patients with and without hypoxemia to determine their risk of complications and survival rate. METHODS: Fifty-eight consecutive Child-Pugh C patients with cirrhosis were included and followed up for 1-18 months. Blood gas measurements and plasma endothelin levels were measured in all patients. Blood gas measurements were repeated in 34 patients. RESULTS: Hypoxemia was present in 35 patients (60%) (alveolar-arterial oxygen (AaO2) gradient > 20 mmHg) but none had pulmonary symptoms. There was no significant difference in liver tests and plasma endothelin levels between hypoxemic and non-hypoxemic patients. The occurrence of variceal bleeding and survival rate was not significantly different between the two groups. The AaO2 gradient worsened in nine patients and normalized in six of the hypoxemic patients. The AaO2 gradient increased to more than 20 mmHg in seven non-hypoxemic patients. There was no relationship between AaO2 gradient changes and Child-Pugh score grade changes. CONCLUSION: Asymptomatic hypoxemia is common in patients with severe cirrhosis but it is not a predictive factor of short-term complications or mortality. These results should be considered when deciding on liver transplantation.

Clinical course, predictive factors and prognosis in patients with cirrhosis and type 1 hepatorenal syndrome treated with Terlipressin: a retrospective analysis.

BACKGROUND AND AIM: Terlipressin has been proposed to treat renal failure in patients with type 1 hepatorenal syndrome (HRS). However, the predictive factors for improved renal function and survival are unknown in patients with type 1 HRS treated with terlipressin. The aim of the present retrospective study was to investigate the predictive factors and prognosis of patients with type 1 HRS treated with terlipressin. METHODS: The clinical charts of 18 consecutive patients with cirrhosis and type 1 HRS treated with terlipressin were studied. The predictive factors for improved renal function and survival were identified using univariate analyses. RESULTS: Improved renal function, indicated by a significant decrease in serum creatinine (61 +/- 4%), occurred in 11 (60%) patients. The only predictive factor for improved renal function was a Child-Pugh's score < or =13 at the time of diagnosis of HRS (P = 0.02). Fifteen patients (83%) died at 45 days and the median survival was 24 days. Of the three patients who survived, two underwent successful orthotopic liver transplantation. Three predictive factors for survival were identified: absence of a precipitating factor for HRS (P = 0.012); improved renal function during terlipressin therapy (P = 0.05); and a dose of terlipressin > or =3 mg/day (P = 0.04). CONCLUSIONS: In patients with type 1 HRS treated with terlipressin, patients with improved renal function had less severe cirrhosis (Child-Pugh >10 but < or =13) than patients without. The predictive factors for survival were the absence of a precipitating factor for HRS, the terlipressin-induced improvement in renal function and a dose of terlipressin of at least 3 mg/day. These findings suggest that a randomized controlled trial investigating the effect of terlipressin on survival in patients with type 1 HRS should be performed.

Role of shear stress in aortic eNOS up-regulation in rats with biliary cirrhosis.

BACKGROUND & AIMS: In rats with portal vein stenosis, the initial cause of aortic nitric oxide (NO) overproduction might be overactivation of endothelial NO synthase (eNOS) related to increased shear stress. Cardiac output is higher in cirrhosis than in extrahepatic portal hypertension. The aims of this study were to evaluate the role of shear stress, vascular endothelial growth factor (VEGF), and cytokines in aortic eNOS up-regulation in rats with biliary cirrhosis and to compare these results with those in rats with portal vein stenosis. METHODS: NOS activities, NOS protein, heat shock protein (Hsp) 90, and VEGF expressions were studied in rat aortas. Propranolol was administered to rats with cirrhosis to reduce cardiac output and thus shear stress. RESULTS: In cirrhotic rats, the aortic eNOS protein was 3.0 and 1.7 times higher than in control and portal vein-stenosed rats, respectively. In cirrhotic rats, the Hsp90 content was 3.2 and 2.2 times higher than in control and portal vein-stenosed rats, respectively. Propranolol decreased NOS activity by 47% and eNOS and Hsp90 expression by 75% and 72%, respectively. Aortic VEGF expression was decreased in cirrhotic rats. VEGF-induced stimulation of NOS activity was greater in aortas from control rats than in aortas from portal vein-stenosed or cirrhotic rat aortas. eNOS expression was up-regulated after VEGF incubation. After lipopolysaccharide administration, eNOS expression did not change in portal vein-stenosed or cirrhotic rats. CONCLUSIONS: This study shows that in aortas from rats with biliary cirrhosis, systemic vasodilation depends mainly on eNOS up-regulation related to shear stress.

Pulmonary hemodynamics and gas exchange after liver transplantation in patients with cirrhosis.

In patients with cirrhosis, discrepant findings have been reported on the evolution of pulmonary hemodynamics and gas exchange after liver transplantation. The aim of this study was to evaluate the effects of liver transplantation on pulmonary and systemic hemodynamics and gas exchange in patients transplanted for cirrhosis. Forty-three patients with cirrhosis underwent hemodynamic investigations before and one year after liver transplantation. Mean pulmonary arterial pressures did not significantly change after transplantation (from 17 +/- 4 to 17 +/- 3 mm Hg) whereas pulmonary vascular resistance significantly increased by 62%. Cardiac index significantly decreased by 20%. PaO2 did not change significantly after transplantation (from 88.8 +/- 13.9 to 88.5 +/- 12.1 mm Hg) and PaCO2 significantly increased by 16%. In conclusion, liver transplantation has no effect on pulmonary pressures but normalizes pulmonary vascular resistance in patients with cirrhosis without pulmonary hypertension. Moreover, it has no major effect on gas exchange in patients with cirrhosis without hypoxemia.

Relationship between protein kinase C alterations and nitric oxide overproduction in cirrhotic rat aortas.

BACKGROUND: Although nitric oxide (NO) overproduction and protein kinase C (PKC) alterations may play a role in systemic haemodynamic changes in cirrhotic rat aortas, the relationship between NO synthase (NOS) hyperactivation and PKC hypoactivation is unknown. Therefore, the relationships between NOS and PKC activities were studied in cirrhotic rat aortas. METHODS: The effects of NOS inhibition by Nw-nitro-L-arginine (LNNA) on the contractile response to phorbol myristate acetate (PMA), a PKC activator, were studied. The effects of NOS inhibition and those of S-nitroso-N acetyl-DL-penicillamine (SNAP), an NO donor, on PKC activity were also evaluated. The effects of PKC activation and inhibition on total NOS and inducible NOS (iNOS) activities were measured. Nitric oxide synthase inhibition caused an increase in PMA-induced contraction and an increase in PKC activity in cirrhotic rat aortas. S-nitroso-N acetyl-DL-penicillamine induced downregulation of PKC activity. Total basal aortic NOS activity was significantly higher in cirrhotic rats than in control rats and activation of PKC by PMA induced a decrease in total aortic NOS activity. Protein kinase C downregulation caused an increase in both total aortic NOS and iNOS activities only in control rats, whereas only iNOS activity increased in cirrhotic rats. CONCLUSION: In cirrhotic rat aortas, NO overproduction plays a role in the decreased PKC activation that leads to reduced aortic contraction. Overactivation of aortic NOS in cirrhotic rats may be because of, in part, the reduced PKC activity.