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

The renal effects of droxidopa are maintained in propranolol treated cirrhotic rats

BACKGROUND & AIMS

Droxidopa improves hemodynamic and renal alterations of cirrhotic rats without changing portal pressure. We aimed to evaluate the effects of a combined treatment with droxidopa and non-selective beta-blockers or statins in order to decrease portal pressure, while maintaining droxidopa beneficial effects.

METHODS

Acute studies combining droxidopa with carvedilol, propranolol or atorvastatin in four-week bile-duct ligated (BDL) rats and a chronic study combining propranolol and droxidopa for 5 days in CCl4 -cirrhotic rats were performed. Hemodynamic values were registered and biochemical parameters from blood and urine samples analyzed.

RESULTS

Bile-duct ligated rats treated with carvedilol + droxidopa showed no changes in mean arterial pressure (MAP) and portal pressure (PP) compared to vehicles. Atorvastatin + droxidopa combination also failed to reduce PP, but maintained the beneficial increase in MAP and superior mesenteric artery resistance (SMAR) and decrease in blood flow (SMABF) caused by droxidopa. In contrast, the acute administration of propranolol + droxidopa significantly reduced PP maintaining a mild increase in MAP and improving, in an additive way, the decrease in SMABF and increase in SMAR caused by droxidopa. This combination also preserved droxidopa diuretic effect. When chronically administered to CCl4 -cirrhotic rats, propranolol + droxidopa caused a decrease in PP, a significant reduction in SMABF and an increase in SMAR. The combination did not alter liver function and droxidopa diuretic and natriuretic effect, and even improved free water clearance.

CONCLUSION

Droxidopa could be effective for the renal alterations of cirrhotic patients on propranolol therapy and the combination of both drugs may balance the adverse effects of each treatment.

Medical management of esophageal varices and portal hypertension in children

Portal hypertension (PH) is a common complication of chronic liver disease in children and represents a cause of morbidity and, rarely, mortality in this group of patients. Although often self-limiting, gastrointestinal bleeding in this setting is regarded as a frightening event by patients and carers, giving the impression of impending death. Therefore, it is important to raise the awareness on the natural history of PH in children, the utility of tools that help preventing and managing acute bleeding, and the signs predicting a poor outcome, thus indicating surgery. There is lack of data on the ability of endoscopy screening, endoscopic treatment of varices, and use of nonselective β-blockers to alter the outcome of PH in children; major efforts should be made to avoid such treatments empirically and promote multicenter trials instead. Nevertheless, such approach should be balanced against the need of offering the best care to children with PH. In this review, we discuss the advances made in the management of PH in children and compare it with the larger adult experience. A rational approach to acute gastrointestinal bleeding is proposed along with an algorithm suggesting a stepwise protocol to manage children with esophageal varices in the long-term, with some hints on possible future studies.

Primary prophylaxis of gastric variceal bleeding comparing cyanoacrylate injection and beta-blockers: a randomized controlled trial

BACKGROUND & AIMS

Gastric variceal bleeding is severe and is associated with high mortality. We compared the efficacy of cyanoacrylate injection and beta-blockers in primary prophylaxis of gastric variceal bleeding.

METHODS

Cirrhotics with large gastroesophageal varices type 2 with eradicated esophageal varices or large isolated gastric varix type 1, who had never bled from gastric varix, were randomised to cyanoacrylate injection (Group I, n=30), beta-blockers (Group II, n=29) or no treatment (Group III, n=30). Primary end-points were bleeding from gastric varix or death.

RESULTS

The actuarial probability of bleeding from gastric varices over a median follow-up of 26 months was 13% in Group I, 28% in Group II (p=0.039), and 45% in Group III (p=0.003). The actuarial probability of survival was higher in the cyanoacrylate compared to the no-treatment group (90% vs. 72%, p=0.048). The median hepatic venous pressure gradient (HVPG) was increased in Group I (14-15 mm Hg, p=0.001) and III (14-16 mm Hg, p=0.001) but decreased in Group II (14 to 12 mm Hg, p=0.001) during follow-up. Size of gastric varix >20 mm, a MELD score ≥17, and presence of portal hypertensive gastropathy predicted 'high risk' of first bleeding from gastric varices.

CONCLUSIONS

Primary prophylaxis is recommended in patients with large and high risk gastric varices to reduce the risk of first bleeding and mortality. Cyanoacrylate injection is more effective than beta-blocker therapy in preventing first gastric variceal bleeding.

Primary prophylaxis of variceal hemorrhage in children with portal hypertension: a framework for future research

Nonselective β-blocker therapy and endoscopic variceal ligation reduce the incidence of variceal hemorrhage in cirrhotic adults, but their use in children is controversial. There are no evidence-based recommendations for the prophylactic management of children at risk of variceal hemorrhage due to the lack of appropriate randomized controlled trials. In a recent gathering of experts at the American Association for the Study of Liver Diseases annual meeting, significant challenges were identified in attempting to design and implement a clinical trial of primary prophylaxis in children using either of these therapies. These challenges render such a trial unfeasible, primarily due to the large sample size required, inadequate knowledge of appropriate dosing of β-blockers, and difficulty in recruiting to a trial of endoscopic variceal ligation. Pediatric research should focus on addressing questions of natural history and diagnosis of varices, prediction of variceal bleeding, optimal approaches to β-blocker and ligation therapy, and alternative study designs to explore therapeutic efficacy in children.

A 3-month course of long-acting repeatable octreotide (sandostatin LAR) improves portal hypertension in patients with cirrhosis: a randomized controlled study

OBJECTIVE

In patients with cirrhosis, acute octreotide administration may transiently decrease the hepatic venous pressure gradient (HVPG). Information on long-term effects of octreotide is limited and controversial. We evaluated portal and systemic hemodynamics following a prolonged administration of long-acting octreotide in patients with cirrhosis.

METHODS

Eighteen cirrhotic patients (alcoholic 12; age 55 yr [44-69]; Pugh's score 7.8; HVPG 17.3 mmHg [12-22]), no steatohepatitis on histology, were randomized to intramuscular octreotide 20 mg (group A) q 4 wk for 3 months or placebo (group B) in a double-blind fashion. At baseline and 3 months, we measured the HVPG, systemic hemodynamics, endothelin-1 (ET-1), and vascular endothelial growth factor (VEGF) in hepatic venous blood.

RESULTS

Patients remained compensated except for one episode of infection in each group. At 3 months, the HVPG decreased in group A but not in group B (16.5 +/- 1.3 to 11.8 +/- 1.5 mmHg, P < 0.01; 18.2 +/- 1 to 17 +/- 1.1 mmHg, P= 0.4). Systemic hemodynamics and liver function remained unchanged. In group A, but not in group B, VEGF decreased (21.2 +/- 4.7 to 13.7 +/- 3.5 pg/mL, P < 0.01; 22.5 +/- 7.8 to 19.2 +/- 5.4 pg/mL, P= 0.4). ET-1 remained stable. Changes in HVPG and VEGF were correlated (r = 0.49, P < 0.05).

CONCLUSIONS

Three months of long-acting octreotide in selected cirrhotic patients with portal hypertension decreases the HVPG independent of systemic hemodynamics and liver function. The decrease in VEGF blood levels suggests an improvement in splanchnic hyperemia.

N/A

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Hemodynamic effects of one week of carvedilol administration on cirrhotic rats

BACKGROUND

Carvedilol is a nonselective beta-blocker with alpha(1)-adrenergic blocking activity. It has been shown to decrease portal pressure in cirrhotic patients. The current study was undertaken to evaluate the possible mechanism of carvedilol on hemodynamics in cirrhotic rats with portal hypertension produced by common bile duct ligation.

METHODS

Male Sprague-Dawley rats received either a sham operation or common bile duct ligation. Three weeks after surgery, both sham-operated and cirrhotic rats were randomly assigned to receive vehicle or carvedilol 5 mg.kg(-1).12 h(-1) by gastric gavage for 1 week. Hemodynamic measurements, serum biochemistry, serum nitrate/nitrite and 6-keto-PGF(1alpha) levels, and aortic mRNA expression of eNOS and COX-1 were performed on the eighth day after drug administration.

RESULTS

Carvedilol treatment did not affect serum biochemistry in either sham-operated or cirrhotic rats. In sham-operated rats, administration of carvedilol significantly decreased the heart rate without affecting other hemodynamic values. In contrast, in cirrhotic rats, administration of carvedilol significantly decreased the cardiac index, portal pressure, heart rate, and portal territory blood flow, and it significantly increased systemic and portal territory vascular resistances. The hepatocollateral resistance was significantly decreased, but the hepatic arterial blood showed no significant changes. In sham-operated rats treated with carvedilol, serum nitrate/nitrite and 6-keto-PGF(1alpha) levels were not affected. In contrast, cirrhotic rats receiving carvedilol showed a significant decrease in serum nitrate/nitrite and 6-keto-PGF(1alpha) levels, associated with a decrease in aortic mRNA expression of eNOS and COX-1 compared with those receiving vehicle.

CONCLUSIONS

Carvedilol decreased portal pressure through a reduction of splanchnic blood flow associated with a decrease in hepatocollateral resistance. Additionally, administration of carvedilol decreased endothelial-related vasodilatory activities.

Research progress of vasculopathy in portal hypertension

Portal hypertension, one of the vascular diseases, not only has lesions in liver, but also changes in vascular structures and functions of extrahepatic portal system, systemic system and pulmonary circulation. The pathological changes of vasculopathy in portal hypertension include remodeling of arterialized visceral veins, intimal injury of visceral veins and destruction of contractile structure in visceral arterial wall. The mechanisms of vasculopathy in portal hypertension may be attributed to the changes of hemodynamics in portal system, immune response, gene modulation, vasoactive substances, and intrahepatic blood flow resistance. Portal hypertension can cause visceral hyperdynamic circulation, and the development and progression of visceral vasculopathy, while visceral vasculopathy can promote the development and progression of portal hypertension and visceral hyperdynamic circulation in turn. The aforementioned three factors interact in the pathogenesis of hepatic cirrhosis-induced portal hypertension and are involved in hemorrhage due to varicose vein rupture.

Pharmacologic efficacy in gastric variceal rebleeding and survival: including multivariate analysis

BACKGROUND

Therapy with beta-blocker and nitrate has been reported to improve survival of patients with bleeding esophageal varices and to decrease esophageal rebleeding. However, there is little information available concerning the efficacy of these medications on rebleeding risk and survival in gastric variceal bleeding after initial hemostasis.

METHODS

We conducted an open trial to observe the roles of beta-blocker and nitrate in the long-term outcome of bleeding gastric varices. Eighty-three patients were included and evaluated on the basis of age, gender, gastric variceal size, associated esophageal variceal size, Child-Pugh classification, existence of hepatoma and portal vein thrombosis, beta-blocker or nitrate therapy, and follow-up histoacryl injection. Survival analysis and multivariate analysis with the Cox proportional hazards model were performed to evaluate independent risk factors.

RESULTS

Larger gastric varices have been shown to be the only risk factor for rebleeding (adjusted odds ratio, 4.50; 95% CI, 1.30-15.59). beta-Blocker and nitrate did not significantly reduce the incidence of rebleeding (adjusted odds ratio, 0.37; 95% CI, 0.08-1.66). Although medical treatment was shown to improve the overall survival by Kaplan-Meier method (p < 0.01), multivariate analysis showed Child-Pugh class B or C and advanced hepatoma with portal vein thrombosis to be the real independent risk factors that influence survival (Child-Pugh class B or C odds ratio, 2.72; 95% CI, 1.53-4.84; portal vein thrombosis odds ratio, 6.99; 95% CI, 2.42-20.16). beta-Blocker and nitrate did not significantly prolong survival independently.

CONCLUSIONS

beta-Blocker and nitrate did not decrease the risk of rebleeding and did not improve the overall survival independently. The poor prognosis was correlated with Child-Pugh class B or C, and the advance hepatoma, with portal vein thrombosis.

Variation at the Angiotensin-converting enzyme and endothelial nitric oxide synthase genes is associated with the risk of esophageal varices among patients with alcoholic cirrhosis

Esophageal varices are a frequent complication among patients with liver cirrhosis. Nitric oxide and other vasoactive molecules regulate the vascular tone in both the liver microcirculation and the systemic and splanchnic circulation. Several genes that encode proteins involved in the maintenance of vascular tone, such as the endothelial-constitutive nitric oxide synthase (ecNOS), the angiotensinogen (AGT), the angiotensin-converting enzyme (ACE), and the angiotensin II receptor type 1 (AT1R) are polymorphic, and these polymorphisms have been associated with several cardiovascular diseases. Our aim was to define a possible role for DNA polymorphisms at these genes in the risk of developing esophageal varices among patients with alcoholic cirrhosis. We analyzed 145 male patients with liver cirrhosis. Patients and 200 healthy controls were genotyped by polymerase chain reaction for the ACE-I/D, the AGT-M235T, the AT1R-A1166C, and the ecNOS-4/5 (intron 4) polymorphisms. Ninety-five patients had varices and 50 did not show this complication. Carriers of the ACE-I allele (ID + II genotypes) were at a significantly higher frequency among patients with varices (p = 0.013). Patients without varices had a higher frequency of the ecNOS-4 allele compared with patients with varices (p = 0.026). ACE-I carriers + ecNOS-55 were at a significantly higher frequency (p = 0.0012; odds ratio = 3.19; 95% CI = 1.55-6.55) among patients with varices (51 of 95, 54%) compared with patients without (18 of 50, 36%). Allele and genotype frequencies for the AGT and AT1R polymorphisms did not differ between the two groups. The genotypes associated with an increased risk for varices have been linked to higher plasma levels of nitric oxide and reduced levels of ACE. These genotypes could have a vasodilatory effect in the systemic and splanchnic circulation, thus favoring the development of portocollaterals.

Management of portal hypertension after variceal hemorrhage

Each variceal bleed is associated with 20% to 30% risk of dying. Management of portal hypertension after a bleed consists of (1) control of bleeding and (2) prevention of rebleeding. Effective control of bleeding can be achieved either pharmacologically by administering somatostatin or octreotide or endoscopically via sclerotherapy or variceal band ligation. In practice, both pharmacologic and endoscopic therapy are used concomitantly. Rebleeding can be prevented by endoscopic obliteration of varices. In this setting, variceal ligation is the preferred endoscopic modality. B-blockade is as effective as endoscopic therapy and, in combination, the two modalities may be additive.

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.

Esophageal varices. I. Clinical presentation, medical therapy, and endoscopic therapy

The last half century has witnessed great advances in the understanding of the pathogenesis and natural history of portal hypertension in cirrhotics. Several pharmacologic and endoscopic techniques have been developed for the treatment of portal hypertension. The use of these agents in a given patient must be based on an understanding of the stage in the natural history of the disease and the relative efficacy and safety of the available treatment options.

Recurrence of esophageal varices following endoscopic treatment and its impact on rebleeding: comparison of sclerotherapy and ligation

BACKGROUND/AIMS

Endoscopic variceal ligation is superior to sclerotherapy because of its lower rebleeding and complication rates. However, ligation is not without drawbacks due to a higher tendency to variceal recurrence. We conducted a randomized cohort study to delineate the long-term history of variceal recurrence following ligation and sclerotherapy, and to clarify the impact of recurrence on rebleeding and on the consumption of endoscopic treatment resources.

METHODS

Two hundred cirrhotic patients with esophageal variceal bleeding were randomized to undergo maintenance endoscopic variceal sclerotherapy or ligation.

RESULTS

One hundred and forty-one patients achieved variceal eradication and were regularly followed up for 2.2 to 6.7 (mean: 5.1 +/- 1.2) years. The demographic data, hepatic reserve, bleeding severity, and endoscopic features of both sclerotherapy (n=70) and ligation (n=71) showed no difference. Forty (57.1%) patients who underwent sclerotherapy experienced 58 recurrences of esophageal varices, in contrast to the 46 (64.8%) patients who underwent ligation and experienced 81 episodes of recurrence. Kaplan-Meier analysis showed that within 2 years variceal recurrence was more frequent for ligation than sclerotherapy, and the difference decreased thereafter. Multiple recurrence appeared more common with ligation (1/2/3/4/5 episodes of recurrence: 46/23/8/3/1 vs. 40/14/3/1/0, p=0.08). On multifactorial analysis, the endoscopic treatment method and red wale markings were the two factors determining variceal recurrence. Rebleeding from recurrent esophageal varices was unusual and showed no difference between the two groups (7/58 vs. 6/81, p>0.05). Rebleeding from gastric varices was more common after eradication by sclerotherapy (7/19 vs. 1/16, p=0.085) than by ligation. The number of sessions required for eradication of recurrent varices was no different between the two groups.

CONCLUSIONS

Early recurrence and multiple recurrence of esophageal varices are more likely in patients undergoing endoscopic ligation, compared to sclerotherapy; however, the recurrence did not lead to a higher risk of rebleeding or require more endoscopic treatment.

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.

Effects of sustained-release lanreotide on hemodynamics in rats with portal vein stenosis

BACKGROUND/AIMS

Somatostatin and its analogue have been shown to provide beneficial effects in the management of portal hypertension and hyperdynamic circulation. The current study was undertaken to evaluate the effects of lanreotide, a sustained-release somatostatin analogue, on hemodynamics in rats with portal hypertension.

METHODS

Immediately after portal vein stenosis, rats were randomly assigned to receive vehicle or a single intramuscular injection of lanreotide 10 mg/kg. Hemodynamic measurements (radioactive microsphere technique) with portal systemic shunts determinations were performed on the 4th and 8th day after surgery, respectively.

RESULTS

On the 4th day after surgery, rats treated with lanreotide had significantly lower cardiac index and higher systemic vascular resistance than rats treated with vehicle, while these values were no different on the 8th day after portal vein stenosis. In contrast, the elevation of portal pressure, portal tributary blood flow, and splanchnic fraction of cardiac output had ameliorated following lanreotide administration associated with an increase in splanchnic arterial resistance. Portal systemic shunts were lower in rats receiving lanreotide than in rats receiving vehicle.

CONCLUSION

The current study showed that a single injection of sustained-release lanreotide in rats with portal vein stenosis delayed the development of peripheral arterial vasodilatation and hyperdynamic circulation, while it modified the evolution of portal hypertension and splanchnic hyperemia. This treatment also prevents, in part, the development of portal systemic shunts in rats with portal vein stenosis.

Effects of octreotide on central hemodynamics and systemic oxygen use in patients with viral cirrhosis

OBJECTIVE

Octreotide has potentially beneficial effects in patients with cirrhosis. However, the effects of octreotide on central hemodynamics and oxygen use have not been established. The present study was undertaken to evaluate the effect of octreotide on central hemodynamics and oxygen use in patients with viral cirrhosis.

METHODS

Twenty-five patients with cirrhosis were enrolled in the study. They were randomly assigned to receive either placebo (n = 10) or a continuous infusion of 100 microg/h of octreotide after an initial 100-microg bolus (n = 15). Hemodynamic measurements and oxygenation values were obtained before and 60 min after octreotide or placebo administration.

RESULTS

Placebo administration did not have any effect on hemodynamic and oxygenation values. In patients who received octreotide, systemic hemodynamic values including cardiac index, mean arterial pressure, and systemic vascular resistance were not affected. The mean pulmonary arterial pressure tended to increase after octreotide administration but was statistically insignificant. There was a significant increase in pulmonary arterial vascular resistance, whereas the pulmonary capillary wedge pressure and right atrial pressure were significantly decreased. Arterial oxygen tension, systemic oxygen uptake, and oxygen extraction ratio were significantly decreased after octreotide administration, whereas oxygen transport as well as arterial and mixed venous oxygen contents remained unchanged.

CONCLUSIONS

In patients with viral cirrhosis, octreotide administration exerted a significant effect on pulmonary circulation. It also resulted in a decrease in systemic oxygen uptake and oxygen extraction ratio. These results suggested that octreotide may impair tissue oxygenation in patients with viral cirrhosis.

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.

Hemodynamic effects of 8-day DL-028 and octreotide administration in rats with portal hypertension

BACKGROUND

DL-028 (chemical name: 3-[[4-(2-methoxyphenyl)piperazin-1-yl]methyl]-2,3-dihydroimidaz o[1,2-c]quinazolin-5(6H)-one (27b)) is a synthetic alpha1-adrenoceptor antagonist. The present study was undertaken to investigate the hemodynamic effects of chronic DL-028 administration, alone or in combination with octreotide, in rats with portal hypertension.

METHODS

Portal hypertension was induced by partial portal-vein ligation. Portal-hypertensive rats were allocated to one of the four groups: vehicle group (saline, 0.5 ml/12 h), octreotide group (30 microg/kg/12 h), DL-028 group (0.4 mg/kg/12 h), and octreotide (30 mg/kg/l2 h) plus DL-028 (0.4 mg/kg/12 h) group, with eight rats in each group. DL-028 or saline was administered by gavage and octreotide by subcutaneous injection. Drugs were given immediately after ligation and for 8 consecutive days thereafter. Systemic and splanchnic hemodynamic variables were measured thereafter.

RESULTS

Portal-vein-ligated rats showed a typical hyperdynamic state as compared with sham-operated rats. The portal venous pressure, portal tributary blood flow, and cardiac index were significantly reduced by treatment with octreotide, DL-028, or octreotide plus DL-028 in portal-hypertensive rats. Hyperdynamic variables of systemic, renal, hepatocollateral, and portal territory vascular resistances and renal and hepatic arterial blood flow were ameliorated by treatment with octreotide or octreotide plus DL-028 in portal-hypertensive rats. Octreotide plus DL-028 treatment exerted better hemodynamic effects on the cardiac index but worse effects on systemic and hepatocollateral vascular resistance than octreotide treatment alone.

CONCLUSION

Although either DL-028 or octreotide ameliorated portal hypertension and splanchnic hyperemia in portal-hypertensive rats, octreotide treatment exerted more beneficial hemodynamic effects than DL-028 treatment. The combination of octreotide and DL-028 conferred no better hemodynamic benefits than octreotide alone, except on the cardiac index.

Portal hypotensive effects of DL-028 and prazosin on portal hypertensive rats

The portal hypotensive effects of prazosin and DL-028 (chem- ical name: 3-[[4-(2-methoxyphenyl)piperazin-1-yl]methyl]- 2, 3-dihydroimidazo[1,2-c]quinazolin-5(6H)-one(27b)), a synthetic alpha1-adrenoceptor antagonist, were assessed in portal hypertensive rats. Portal hypertension was induced by partial portal vein ligation in Sprague-Dawley rats. Two weeks after ligation, when the hyperdynamic state was stabilized the rats were anesthetized after an overnight fast and cannulated for measuring mean arterial pressure (MAP), portal venous pressure (PVP), cardiac index (CI) and heart rate (HR). Both DL-028 and prazosin (1, 3.3 and 10 microgram/kg) induced dose-dependent decreases of PVP and MAP after intravenous infusion, with effects lasting for longer than 30 min. The maximum percentage reduction of PVP after DL-028 was 10, 10 and 15%, respectively, for the dosages given (1, 3.3 and 10 microgram/kg), and 5, 12 and 25%, respectively, after prazosin. CI was not changed by either drug. HR was not changed by either drug except DL-028 at 10.0 microgram/kg with a bradycardiac effect. Our results showed that both DL-028 and prazosin reduced PVP in portal hypertensive rats.

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.

Effects of tetramethylpyrazine on portal hypertensive rats

The effects of tetramethylpyrazine, an alkaloid isolated from a Chinese herb Ligusticum wallichii Franch have been assessed in portal hypertensive rats. Portal hypertension was induced by partial portal vein ligation in Sprague-Dawley rats. Two weeks after ligation, when the hyperdynamic state had stabilized, rats were anaesthetized after an overnight fast and cannulated for measurement of mean arterial pressure, portal venous pressure, cardiac index and heart rate. Tetramethylpyrazine (3.0, 9.9 and 30mgkg(-1)) induced dose-dependent reductions of portal venous pressure and mean arterial pressure after intravenous infusion. The maximum percentage reduction of portal venous pressure after tetramethylpyrazine was 6.0+/-0.8, 9.3+/-1.6 and 20+/-2% of baseline for doses of 3.0, 9.9 and 30.0mgkg(-1), respectively. Also, total peripheral resistance was significantly reduced by tetramethylpyrazine and cardiac index was slightly increased. Our results showed that tetramethylpyrazine induced portal pressure reduction in portal hypertensive rats.

Medical decompressive therapy for prophylaxis of rebleeding

Among diVerent substances which decrease the degree of portal hypertension, only β-adrenoceptor antagonists are used to prevent recurrent hemorrhage in patients with cirrhosis [1]. Controlled trials comparing endoscopic sclerotherapy with or without β-adrenoceptor antagonists have also been performed.

Vascular hyporeactivity persists despite increased contractility after long-term administration of isosorbide dinitrate in portal hypertensive rats

BACKGROUND/AIMS

Portal hypertension is associated with decreased vascular responsiveness to vasoconstrictors, which may contribute to the hyperdynamics. Isosorbide dinitrate is an effective portal hypotensive drug. The present study aimed to investigate whether chronic administration of isosorbide dinitrate could affect vascular responsiveness in portal hypertensive rats.

METHODS

Portal hypertension was induced by partial portal vein ligation. Sham-operated (Sham) rats served as controls. There were four animal groups for this study: portal vein ligation-isosorbide dinitrate group, portal vein ligation-vehicle (Veh) group, Sham-isosorbide dinitrate group and Sham-Veh group. Isosorbide dinitrate (5 mg x kg(-1) x 12 h(-1) was given by gavage for 8 days starting 1 day before ligation and continuing thereafter. Mesenteric arteries were removed for contractile study after hemodynamic measurement.

RESULTS

Contractile responses to KCI (15-90 mM) and phenylephrine (10(-9)-10(-4) M) were recorded. Both vascular reactivity and sensitivity were significantly reduced in portal vein ligation rats as compared to Sham rats. Chronic isosorbide dinitrate treatment reduced portal venous pressure in portal vein ligation rats. Moreover, the maximal contractile responses to KCl and phenylephrine were significantly enhanced in both portal vein ligation and Sham rats after isosorbide dinitrate treatment, but relative hyporeactivity persisted in portal vein ligation rats. In contrast, a single dose of isosorbide dinitrate did not alter the contractile sensitivity or reactivity to KCl or phenylephrine in either portal vein ligation or Sham rats.

CONCLUSION

Our results show that long-term administration of isosorbide dinitrate enhanced vascular contractility in both portal vein ligation and Sham rats, but relative hyporeactivity persisted in portal vein ligation rats.

Haemodynamic effects of chronic octreotide and tetrandrine administration in portal hypertensive rats

Octreotide is an effective portal hypotensive drug in the control of variceal bleeding. Tetrandrine is a type of calcium channel blocker recently reported to reduce portal hypertension. The present study was undertaken to investigate the haemodynamic effects of octreotide and tetrandrine, alone and in combination, in portal hypertensive rats. 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/day), octreotide group (100 microg/kg per 12 h), tetrandrine group (20 mg/kg per 12 h), and octreotide (100 microg/kg per 12 h) plus tetrandrine (20mg/kg per 12 h) group. Tetrandrine or saline was administered by gavage, and octreotide by subcutaneous injection. The drug was given for 8 consecutive days, starting 1 day before ligation and continuing onwards. Haemodynamic parameters were measured thereafter, using the radioactive microsphere method. The portal venous pressure and portal tributary blood flow were significantly reduced, while portal territory and renal vascular resistances were significantly enhanced, by octreotide, tetrandrine, or octreotide plus tetrandrine in portal hypertensive rats, compared with the vehicle group. Our results showed that long-term administration of octreotide, tetrandrine, or octreotide plus tetrandrine led to portal hypotensive effects in portal hypertensive rats, but octreotide alone exerted better anti-hyperdynamic effects compared with tetrandrine alone. A combination of octreotide and tetrandrine offered no major beneficial anti-hyperdynamic effects compared with octreotide alone.

Acute and chronic haemodynamic effects of naftazone in portal hypertensive rats

It has been demonstrated that hyperproduction of nitric oxide (NO) plays a major role in the vasodilatation of cirrhosis; thus, the vasodilatation might be reversed by an inhibition of NO production. Experimental studies in isolated aortic rings showed that naftazone inhibits the effects of NO production. The aim of this study was to evaluate the haemodynamic effects of acute and chronic administration of naftazone in rats with portal hypertension. Haemodynamic values were measured either before and 10 min after intravenous administration of 432 microg/kg of naftazone or after 4 days of oral administration of 10 mg/kg per day. Acute administration of naftazone significantly reduced portal pressure in portal vein-stenosed and cirrhotic rats. This reduction was related to a decrease in the resistance of the liver and collateral circulation and it was associated with an increased cardiac output. Oral administration of naftazone significantly decreased portal pressure in rats with portal vein stenosis; this decrease depended on a significant reduction of portal blood flow. In both groups, arterial pressure did not change significantly. These haemodynamic effects differed from those observed following prazosin or propranolol administration. However, these effects were similar but less marked than those observed following N-nitro-L-arginine administration in systemic and splanchnic arterial territories. In conclusion, acute and oral administration of naftazone significantly reduces portal pressure by two different mechanisms in portal hypertensive rats. The exact mechanism has, however, to be elucidated.

Haemodynamic effects of chronic tetrandrine treatment in portal hypertensive rats

Tetrandrine is a calcium channel antagonist with reported antihypertensive effect. However, the potential role of tetrandrine as a therapeutic agent in portal hypertension has yet to be explored. The present study aimed to investigate the haemodynamic effects of chronic tetrandrine treatment on portal hypertensive rats. Portal hypertension was induced by partial portal vein ligation in Sprague-Dawley rats. Animals were allocated into one of two groups: a tetrandrine group and a vehicle group. Tetrandrine (20 mg/kg) or vehicle was administered by gavage every 12 h for 8 consecutive days, starting 1 day before ligation and continuing thereafter. After 8 days of tetrandrine treatment, systemic haemodynamics, organ blood flow and the degree of portal-systemic shunting were measured after an overnight fast. The portal venous pressure and protal tributary blood flow were significantly decreased, while portal territory as well as hepto-collateral vascular resistance significantly increased in the tetrandrine group compared with the vehicle group. The cardiac index was increased, while systemic vascular resistance was decreased, the the tetrandrine group. Mean arterial pressure, heart rate, portal-systemic shunting and bodyweight were similar between the two groups. Renal blood flow was decreased in the tetrandrine group. In conclusion, long-term treatment of tetrandrine reduced portal venous pressure and alleviated splanchnic hyperaemina in portal hypertensive rats without affecting the portal-systemic shunting.

Review: pharmacotherapeutic agents in the treatment of portal hypertension

Certain vasoactive substances reduce portal pressure in patients or animals with portal hypertension by either inducing splanchnic vasoconstriction or reducing hepatic vascular resistance. Studies have shown that propranolol or nadolol significantly reduce the risk of a first episode of gastrointestinal (GI) bleeding and increase the survival rate in patients with cirrhosis and oesophageal varices. Isosorbide-5-mononitrate is also effective in the prevention of bleeding. The combination of beta-blockers and nitrates may be more effective than one drug alone. These results show that beta-adrenoceptor antagonists must be used to prevent the first episode of GI bleeding. Beta-blocker administration also significantly reduces the risk of recurrent GI bleeding and increases the survival rate in patients with cirrhosis. Studies have shown that propranolol is as effective as endoscopic sclerotherapy. The combination of a beta-blocker with endoscopic sclerotherapy may be more effective than pharmacological or endoscopic treatment alone for the prevention of rebleeding. Finally, new experimental and clinical studies are needed to improve the pharmacological treatment of portal hypertension.

Portal hypotensive effects of tetrandrine and verapamil in portal hypertensive rats

The portal hypotensive effects of tetrandrine and verapamil (both calcium-channel blockers) were assessed in portal hypertensive rats. Portal hypertension was induced by partial portal vein ligation in Sprague-Dawley rats. Both tetrandrine (4, 8, 16 and 24 mg kg-1) and verapamil (0.5, 1.0, 1.5 and 2.0 mg kg-1) induced dose-dependent decreases of portal venous pressure and mean arterial pressure after intravenous infusion. for example, infusion of tetrandrine (16 mg kg-1) induced a maximum reduction of portal venous pressure and mean arterial pressure approximately 1 min after the start of infusion. Portal venous pressure decreased from baseline (12.5 mmHg) to 10.0 mmHg, and mean arterial pressure from baseline (90 mmHg) to 80 mmHg. Heart rate decreased from 250 to 240 beats min-1. At 24 mg kg-1, tetrandrine reduced portal venous pressure and mean arterial pressure to 20.3 +/- 2.4% and 28.4 +/- 1.4% of baseline, respectively. Our results show that both tetrandrine and verapamil induce portal pressure reduction in portal hypertensive animals.

Effects of superior mesenteric artery stenosis on splanchnic and systemic hemodynamics in conscious rats with biliary cirrhosis

BACKGROUND/AIMS

Since portal tributary blood flow is increased in portal hypertension due to cirrhosis, a reduction in mesenteric arterial blood flow should decrease portal pressure.

METHODS

Calibrated stenosis of the superior mesenteric artery was performed in bile duct ligated rats, using a 22-gauge needle. Arterial stenosis was performed 4 weeks after bile duct ligation. Hemodynamic studies were performed in the 5th week following bile duct ligation in conscious rats.

RESULTS

At that time, no digestive tract alterations were observed. In rats with mesenteric arterial stenosis, portal pressure was 12.2 +/- 2.0 mmHg; this value was lower than in rats with cirrhosis without arterial stenosis (14.5 +/- 1.1 mmHg) but higher than normal rats (5.8 +/- 0.7 mmHg). In rats with cirrhosis with mesenteric arterial stenosis, portal tributary and mesenteric blood flows were lower than in rats with cirrhosis without arterial stenosis and not significantly different from normal rats. In rats with mesenteric stenosis, cardiac index was significantly lower than in rats with cirrhosis and not significantly different from normal rats.

CONCLUSION

This study shows that calibrated superior mesenteric arterial stenosis normalized portal tributary blood flow and reduced but did not normalize the degree of portal hypertension.