Hemodynamic effects of a combination of vasopressin and ketanserin in patients with hepatitis b-related cirrhosis

Effects of vasopressin on portal-systemic collaterals of cirrhotic rats

OBJECTIVE

Arginine vasopressin (AVP) exerts a constrictive effect on the portal-systemic collaterals of non-cirrhotic portal hypertensive rats, but its effect on cirrhotic rats is unknown. The aim of this study was to investigate the response of AVP and the modulatory roles of nitric oxide and prostaglandin on collaterals of common bile duct-ligated (BDL) cirrhotic rats.

MATERIAL AND METHODS

The collateral vascular responsiveness to graded concentrations of AVP (10(-10) - 3 x 10(-7) M) was tested by an in situ collateral perfusion system pretreated with Nomega-nitro-L-arginine (L-NNA, 100 microM), indomethacin (INDO, 10 microM), or both. The collateral responses to AVP with the pretreatment of a vasopressin V1 receptor antagonist d(CH2)5Tyr(Me) arginine vasopressin or a V2 receptor agonist 1-desamino-8-D-arginine vasopressin (DDAVP, 10(-10) - 3 x 10(-7) M) were also evaluated.

RESULTS

The perfusion pressure of collaterals was significantly increased by AVP, and this effect was inhibited by the addition of the V1 receptor antagonist. DDAVP had no effect on the collaterals. Incubation with L-NNA or L-NNA plus INDO, but not INDO alone, significantly potentiated the constrictive effects of AVP. The constrictive effect of AVP in the combination group was similar to that in the L-NNA alone group.

CONCLUSIONS

The results show that AVP produces a direct vasoconstrictive effect on the portal-systemic collaterals of BDL cirrhotic rats. The constrictive effect of AVP is mediated by the vasopressin V1, instead of V2, receptors. Nitric oxide may play a more important role than prostaglandin in modulating the collateral vascular response to AVP in BDL cirrhotic rats.

Hemodynamic effects of a combination of prazosin and terlipressin in patients with viral cirrhosis

OBJECTIVES

Terlipressin reduces portal pressure in cirrhotic patients mainly through intense splanchnic vasoconstriction that decrease portal venous inflow. Hepatic blood flow may also be reduced by terlipressin. Prazosin (an alpha1-adrenoceptor antagonist) has also been proposed to decrease portal pressure in cirrhotic patients possibly through a decrease in the intrahepatic vascular resistance. The current study was aimed to evaluate whether a combination of prazosin and terlipressin exerts more beneficial effects than terlipressin alone.

METHODS

Patients were randomly assigned to receive either a placebo (n = 12) or an oral administration of prazosin 2 mg (n = 12). Thereafter, each patient received an intravenous injection of terlipressin 2 mg. Hemodynamic values were measured basally, 30 min after prazosin or placebo, and 30 min after terlipressin.

RESULTS

Placebo administration did not affect any hemodynamic values. Terlipressin administration, on the other hand, resulted in expected changes on the hepatic venous pressure gradient, hepatic blood flow, and systemic hemodynamics. In contrast, prazosin significantly decreased hepatic venous pressure gradient with an increased hepatic blood flow and intrinsic hepatic clearance. After terlipressin administration, a further decrease in hepatic venous pressure gradient was observed with preservation of hepatic blood flow and intrinsic hepatic clearance. The magnitude of decrease in hepatic venous pressure gradient was more profound in patients receiving prazosin plus terlipressin than in those receiving terlipressin alone. However, the magnitude of changes in systemic hemodynamics was no different between the two groups of patients.

CONCLUSIONS

The current study showed that a combination of prazosin and terlipressin resulted in a more profound reduction of hepatic venous pressure gradient with a preservation of hepatic blood flow and intrinsic hepatic clearance than did terlipressin alone. However, the combined therapy did not modify the systemic hemodynamic effects exerted by terlipressin.

Beneficial effects of combined terlipressin and tetramethylpyrazine administration on portal hypertensive rats

The purpose of this study was to investigate the therapeutic effects of terlipressin (TP) alone or in combination with tetramethylpyrazine (TMP) on anesthetized portal hypertensive rats. Portal hypertension was induced by either partial portal vein ligation (PVL, without cirrhosis) or bile duct ligation (BDL, with cirrhosis) in Sprague-Dawley rats. Each PVL or BDL rat received only one of the two regimens: vehicle for 3 min followed by TP (0.017 mg·kg-1·min-1 for 3 min) or TMP (10 mg·kg-1·min-1 for 3 min) followed by TP. In PVL rats, infusion of vehicle followed by TP induced significant reduction of portal venous pressure (PVP, -15.0 ± 1.0%) and prominent elevation of mean arterial pressure (MAP, 57.3 ± 8.1%) as well as total peripheral resistance (TPR, 113 ± 11%) from baseline, and there was a cardiodepressant response (cardiac index, CI, -26.3 ± 1.1%). Infusion of TMP followed by TP induced significant reduction of PVP (-20.3 ± 0.4%) and CI (-9.9 ± 1.2%) and significant elevation of MAP (31.3 ± 2.5%) and TPR (46.0 ± 4.1%) from baseline. In BDL rats, infusion of vehicle followed by TP also induced significant reduction of PVP (-13.8 ± 1.7%) but an increase in MAP (57.1 ± 2.2%) and TPR (101 ± 6%) from baseline, and there also was a cardiodepressant response (CI, -21.4 ± 2.3%). Infusion of TMP followed by TP induced significant reduction of PVP (-18.9 ± 1.4%) and CI (-11.9 ± 2.1%), but an increase in MAP (36.2 ± 2.5%) and TPR (55.0 ± 5.2%). Compared with vehicle followed by TP, TMP not only significantly enhanced portal hypotensive (PVP reduction) effects of TP but also attenuated the systemic pressor (MAP and TPR elevation) and cardiodepressant (CI reduction) effects of TP in both PVL and BDL rats. Our results suggest that TP, alone or in combination with TMP, induced portal hypotensive effects in two models of portal hypertensive rats. Combination of TP and TMP was beneficial in enhancing portal hypotensive effects of TP and ameliorating the systemic pressor and cardiodepressant effects of TP.Key words: terlipressin, tetramethylpyrazine, cirrhosis, portal hypertension, hemodynamics.

Portal hypotensive effects of combined terlipressin and DL-028, a synthetic alpha 1 adrenoceptor antagonist administration on anesthetized portal hypertensive rats

AIMS/BACKGROUND

The purpose of this study was to investigate the therapeutic effects of terlipressin, alone or in combination with DL-028, a synthetic alpha 1-adrenoceptor antagonist on anesthetized portal hypertensive rats.

METHODS

Portal hypertension was induced by either partial portal vein ligation (PVL) or bile duct ligation (BDL) in Sprague-Dawley rats. Each portal hypertensive rat received only one of the two regimens: vehicle plus terlipressin or DL-028 plus terlipressin. Terlipressin dosage was 0.017 mg/kg/min infused for 3 min, while vehicle or DL-028 (0.50 microgram/kg/min) was continuously infused for 40 min, starting 10 min before terlipressin infusion.

RESULTS

In PVL rats, infusions of vehicle plus terlipressin induced significant, maximum reduction of portal venous pressure (PVP, -11.0 +/- 1.8%) and prominent elevation of mean arterial pressure (MAP, 50.3 +/- 9.0%) from baseline. Infusions of DL-028 plus terlipressin induced maximum PVP reduction (-17.5 +/- 2.8%) and MAP elevation (39.8 +/- 7.4%). In BDL rats, infusion of vehicle plus terlipressin also induced significant, maximum reduction of PVP (-6.8 +/- 2.1%) and prominent elevation of MAP (61.4 +/- 7.8%) from baseline. Infusions of DL-028 plus terlipressin induced maximum PVP reduction (-17.9 +/- 2.2%) and MAP elevation (47.9 +/- 7.4%). Compared to vehicle plus terlipressin, DL-028 significantly enhanced portal hypotensive effects of and attenuated systemic pressor effects of terlipressin in both PVL and BDL rats.

CONCLUSIONS

Our results suggest that terlipressin, alone or in combination with DL-028, induced portal hypotensive effects in portal hypertensive rats. The combination of terlipressin with DL-028 was beneficial in enhancing the portal hypotensive effects and ameliorating the systemic pressor effects of terlipressin.

Haemodynamic effects of 8-day octreotide and prazosin administration in portal hypertensive rats

BACKGROUND

Octreotide and prazosin are both effective portal hypotensive drugs in the control or prevention of variceal bleeding. The present study was undertaken to investigate the haemodynamic effects of octreotide and prazosin, alone or in combination, in portal hypertensive rats.

METHODS

Portal hypertension was induced by partial portal vein ligation. Portal hypertensive rats were allocated into one of the four groups-vehicle group (saline, 0.5 mL 12 h-1), octreotide group (30 micrograms kg-1 12 h-1), prazosin group (0.4 mg kg-1 12 h-1), and octreotide (30 micrograms kg-1 12 h-1) plus prazosin (0.4 mg kg-1 12 h-1) group-with eight rats in each group. Prazosin or saline was administered by gavage, whereas octreotide was administered by subcutaneous injection. The drug was given on the day of ligation and continued for 8 consecutive days. Systemic as well as splanchnic haemodynamic parameters were measured thereafter.

RESULTS

Portal vein-ligated rats exhibited typical hyperdynamic state compared with sham-operated rats. The portal venous pressure, portal tributary blood flow and cardiac index were significantly reduced by treatment of octreotide, prazosin or octreotide plus prazosin in portal hypertensive rats. Hyperdynamic parameters of systemic, renal and portal territory vascular resistances, and renal as well as hepatic arterial blood flow were ameliorated by treatment of octreotide or octreotide plus prazosin in portal hypertensive rats. Overall, octreotide treatment exerted more beneficial haemodynamic effects than prazosin treatment. The combination of octreotide and prazosin exerted better haemodynamic effects in cardiac index but worse effects in systemic as well as portal territory vascular resistance than octreotide treatment alone.

Hemodynamic effects of combined treatment with somatostatin analogue (SMS 201-995) and low-dose isosorbide dinitrate on portal hypertension in conscious cirrhotic rats

The authors investigated whether combined treatment with the somatostatin analogue, SMS 201-995, and low-dose isosorbide dinitrate enhanced the hemodynamic effects of the individual agents on rats with thioacetamide-induced cirrhosis. Four groups of cirrhotic rats received SMS 201-995 (0.1 microgram.min-1.kg-1), isosorbide dinitrate (10 micrograms.min-1.kg-1), both agents, or placebo, respectively. Hemodynamics were measured serially in conscious rats, using a radioactive microsphere method. SMS 201-995 reduced portal venous inflow 21 +/- 4% and portal pressure 17 +/- 3%. Isosorbide dinitrate decreased portal venous inflow 20 +/- 4%, by inducing splanchnic vasoconstriction mediated by low pressure baroreflexes, and this agent also decreased portal pressure, by 14 +/- 2%. Portal venous resistance rose 7.6 +/- 3% with isosorbide dinitrate alone, but decreased 18 +/- 4% with combination therapy. This effect may have been induced by the pronounced vasodilatory effect of isosorbide dinitrate on the venous vasculature, since the reflex splanchnic vasoconstriction that occurs with low-dose isosorbide dinitrate disappears when this agent is combined with SMS 201-995. The decrease in portal pressure was more marked (22 +/- 4%) and changes in systemic hemodynamics were milder with the combined treatment. It was concluded that combination therapy with SMS 201-995 and low-dose isosorbide dinitrate may be beneficial for portal hypertension in liver cirrhosis.

Pharmacological treatment of portal hypertension: hemodynamic effects and prevention of bleeding

In the past 10 years, it has been clearly shown that vasoactive substances reduce portal pressure in patients or animals with portal hypertension. Some of these substances act by inducing splanchnic vasoconstriction, while others reduce hepatic and porto-systemic collateral vascular resistance and, thus, induce a portal hypotensive effect. Still others induce arterial hypotension, which causes a vasoconstrictive effect in the splanchnic territory. Since these drugs act on different vascular receptors, their combination should have a more marked effect on portal hypertension. Up to now, only nonselective beta-blockers have been used in the prevention of first gastrointestinal bleeding in patients with portal hypertension and esophageal varices and in the prevention of recurrent gastrointestinal bleeding. These trials have shown that propranolol or nadolol significantly reduce either a first episode of bleeding or recurrent bleeding. This pharmacological treatment also improves the survival rate in these patients. All of these studies have helped us to understand, in part, why gastrointestinal hemorrhage occurs in certain patients. Additional studies of beta-blockers or other substances are, nevertheless, necessary to select patients who will respond to this type of treatment. Finally, it is possible that the pharmacological treatment of portal hypertension may also be used before esophageal varices occur.