Portal pressure response to losartan compared with propranolol in patients with cirrhosis

From Pathophysiology to Practice: Evolving Pharmacological Therapies, Clinical Complications, and Pharmacogenetic Considerations in Portal Hypertension

Background: Portal hypertension is a major complication of chronic liver diseases, leading to serious issues such as esophageal variceal bleeding. The increase in portal vein pressure is driven by both an organic component and a functional component, including tonic contraction of hepatic stellate cells. These processes result in a pathological rise in intrahepatic vascular resistance, stemming from partial impairment of hepatic microcirculation, which is further exacerbated by abnormalities in extrahepatic vessels, including increased portal blood flow. Objectives: This review aims to provide a comprehensive overview of the evolving pharmacological therapies for portal hypertension, with consideration and discussion of pathophysiological mechanisms, clinical complications, and pharmacogenetic considerations, highlighting potential directions for future research. Methods: A review of recent literature was performed to evaluate current knowledge and potential therapeutic strategies in portal hypertension. Results: For over 35 years, non-selective beta-blockers have been the cornerstone therapy for portal hypertension by reducing portal vein inflow as an extrahepatic target, effectively preventing decompensation and variceal hemorrhages. However, since not all patients exhibit an adequate response to non-selective beta-blockers (NSBBs), and some may not tolerate NSBBs, alternative or adjunctive therapies that enhance the effects of NSBBs on portal pressure are being investigated in preclinical and early clinical studies. Conclusions: A better understanding of pharmacogenetic factors and pathophysiological mechanisms could lead to more individualized and effective treatments for portal hypertension. These insights highlight potential directions for future research.

The Renin-Angiotensin System in Liver Disease

The renin-angiotensin system (RAS) is a complex homeostatic entity with multiorgan systemic and local effects. Traditionally, RAS works in conjunction with the kidney to control effective arterial circulation, systemic vascular resistance, and electrolyte balance. However, chronic hepatic injury and resulting splanchnic dilation may disrupt this delicate balance. The role of RAS in liver disease, however, is even more extensive, modulating hepatic fibrosis and portal hypertension. Recognition of an alternative RAS pathway in the past few decades has changed our understanding of RAS in liver disease, and the concept of opposing vs. "rebalanced" forces is an ongoing focus of research. Whether RAS inhibition is beneficial in patients with chronic liver disease appears to be context-dependent, but further study is needed to optimize clinical management and reduce organ-specific morbidity and mortality. This review presents the current understanding of RAS in liver disease, acknowledges areas of uncertainty, and describes potential areas of future investigation.

Evolution of care in cirrhosis: Preventing hepatic decompensation through pharmacotherapy

Cirrhosis is a leading cause of morbidity and mortality, impacting more than 120 million people worldwide. Although geographic differences exist, etiologic factors such as alcohol use disorder, chronic viral hepatitis infections, and non-alcoholic fatty liver disease are prevalent in nearly every region. Historically, significant effort has been devoted to modifying these risks to prevent disease progression. Nevertheless, more than 11% of patients with compensated cirrhosis experience hepatic decompensation each year. This transition signifies the most important prognostic factor in the natural history of the disease, corresponding to a decline in median survival to below 2 years. Over the past decade, the need for pharmacotherapies aimed at reducing the risk for hepatic decompensation has been emphasized, and non-selective beta-blockers have emerged as the most effective option to date. However, a critical therapeutic gap still exists, and additional therapies have been proposed, including statins, rifaximin, and sodium-glucose cotransporter-2 inhibitors. Based on the results of innovative retrospective analyses and small-scale prospective trials, these pharmacotherapies represent promising options, but further studies, including randomized controlled trials, are necessary before they can be incorporated into clinical use. This report highlights the potential impact of these agents and others in preventing hepatic decompensation and discusses how this paradigm shift may pave the way for guideline-directed medical therapy in cirrhosis.

Current and investigational drugs in early clinical development for portal hypertension

Introduction

The development of portal hypertension leads to a majority of complications associated with chronic liver disease. Therefore, adequate treatment of portal hypertension is crucial in the management of such patients. Current treatment options are limited and consist mainly of medications that decrease the hyperdynamic circulation, such as non-selective beta blockers, and treatment of hypervolemia with diuretics. Despite these options, mortality rates have not improved over the last two decades. Newer, more effective treatment options are necessary to help improve survival and quality of life in these patients.

Areas covered

Multiple preclinical models and clinical studies have demonstrated potential efficacy of a variety of new treatment modalities. We introduce treatment options including the use of vasodilation promotors, vasoconstriction inhibitors, anticoagulants, antiangiogenics, and anti-inflammatory drugs. We examine the most recent studies for treatment options within these drug classes and offer insights as to which show the most promise in this field.

Methodology

Published studies that identified novel medical treatment options of portal hypertension were searched using PubMed (https://pubmed.ncbi.nlm.nih.gov/). Clinical trials listed in Clinicaltrials.gov were also searched with a focus on more recent and ongoing studies, including those with completed recruitment. Searching with key terms including "portal hypertension" as well as individually searching specific treatment medications that were listed in other publications was carried out. Finally, current societal guidelines and recent review articles relevant to the management of portal hypertension were evaluated, and listed references of interest were included.

Conclusion

Many ongoing early phase studies demonstrate promising results and may shape the field of portal hypertension management in future. As concrete results become available, larger RCTs will be required before making definitive conclusions regarding safety and efficacy and whether or not they can be incorporated into routine clinical practice. Statins, anticoagulants, and PDE inhibitors have been among the most studied and appear to be most promising.

Current Topics of the Mechanism of Intestinal Fibrosis in Crohn’s Disease

Intestinal fibrosis is one of the most common intestinal complications observed in inflammatory bowel disease, especially Crohn’s disease (CD). Intestinal fibrosis in CD is associated with chronic inflammation resulting from immunologic abnormalities and occurs as a form of tissue repair during the anti-inflammatory process. Various types of immune cells and mesenchymal cells, including myofibroblasts, are intricately involved in causing intestinal fibrosis. It is often difficult to treat intestinal fibrosis as intestinal stricture may develop despite treatment aimed at controlling inflammation. Detailed analysis of the pathogenesis of intestinal fibrosis is critical towards advancing the development of future therapeutic applications.

The differential activation of cardiovascular hormones across distinct stages of portal hypertension predicts clinical outcomes

Background and aims

The cardiovascular hormones renin/angiotensin/aldosterone (RAA), brain-type natriuretic peptide (BNP)and arginine-vasopressin (AVP) are key regulators of systemic circulatory homeostasis in portal hypertension (PH). We assessed (i) the activation of renin, BNP and AVP across distinct stages of PH and (ii) whether activation of these hormones correlates with clinical outcomes.

Methods

Plasma levels of renin, proBNP and copeptin (AVP biomarker) were determined in 663 patients with advanced chronic liver disease (ACLD) undergoing hepatic venous pressure gradient (HVPG) measurement at the Vienna General Hospital between 11/2011 and 02/2019. We stratified for Child stage (A–C), HVPG (6–9 mmHg, 10–15 mmHg, ≥ 16 mmHg) and compensated vs. decompensated ACLD.

Results

With increasing PH, hyperdynamic state was indicated by higher heart rates (6–9 mmHg: median 71.0 [IQR 18.0] bpm, 10–15 mmHg: 76.0 [19.0] bpm, ≥ 16 mmHg: 80.0 [22.0] bpm; p < 0.001), lower mean arterial pressure (6–9 mmHg: 103.0 [13.5] mmHg, 10–15 mmHg: 101.0 [19.5] mmHg, ≥ 16 mmHg: 99.0 [21.0] mmHg; p = 0.032) and lower serum sodium (6–9 mmHg: 139.0 [3.0] mmol/L, 10–15 mmHg: 138.0 [4.0] mmol/L, ≥ 16 mmHg: 138.0 [5.0] mmol/L; p < 0.001). Across HVPG strata (6–9 mmHg vs. 10–15 mmHg vs ≥ 16 mmHg), median plasma levels of renin (21.0 [50.5] vs. 25.1 [70.9] vs. 65.4 [219.6] µIU/mL; p < 0.001), proBNP (86.1 [134.0] vs. 63.6 [118.0], vs. 132.2 [208.9] pg/mL; p = 0.002) and copeptin (7.8 [7.7] vs. 5.6 [8.0] vs. 10.7 [18.6] pmol/L; p = 0.024) increased with severity of PH. Elevated renin levels independently predicted first hepatic decompensation (adjusted hazard ratio [aHR]: 1.69; 95% confidence interval [95% CI] 1.07–2.68; p = 0.025) and mortality in compensated patients (aHR: 3.15; 95% CI 1.70–5.84; p < 0.001) and the overall cohort aHR: 1.42; 95% CI 1.01–2.01; p = 0.046). Elevated copeptin levels predicted mortality in decompensated patients (aHR: 5.77; 95% CI 1.27–26.33; p = 0.024) and in the overall cohort (aHR: 3.29; 95% CI 1.36–7.95; p = 0.008). ProBNP levels did not predict clinical outcomes.

Conclusions

The cardiovascular hormones renin, proBNP and AVP are activated with progression of ACLD and PH. Renin activation is a risk factor for hepatic decompensation and mortality, especially in compensated patients. Increased plasma copeptin is a risk factor for mortality, in particular in decompensated patients.

Supplementary Information

The online version contains supplementary material available at 10.1007/s12072-021-10203-9.

Primary prevention of variceal bleeding in people with oesophageal varices due to liver cirrhosis: a network meta-analysis

BACKGROUND

Approximately 40% to 95% of people with cirrhosis have oesophageal varices. About 15% to 20% of oesophageal varices bleed in about one to three years. There are several different treatments to prevent bleeding, including: beta-blockers, endoscopic sclerotherapy, and variceal band ligation. However, there is uncertainty surrounding their individual and relative benefits and harms.

OBJECTIVES

To compare the benefits and harms of different treatments for prevention of first variceal bleeding from oesophageal varices in adults with liver cirrhosis through a network meta-analysis and to generate rankings of the different treatments for prevention of first variceal bleeding from oesophageal varices according to their safety and efficacy.

SEARCH METHODS

We searched CENTRAL, MEDLINE, Embase, Science Citation Index Expanded, World Health Organization International Clinical Trials Registry Platform, and trials registers to December 2019 to identify randomised clinical trials in people with cirrhosis and oesophageal varices with no history of bleeding.

SELECTION CRITERIA

We included only randomised clinical trials (irrespective of language, blinding, or status) in adults with cirrhosis and oesophageal varices with no history of bleeding. We excluded randomised clinical trials in which participants had previous bleeding from oesophageal varices and those who had previously undergone liver transplantation or previously received prophylactic treatment for oesophageal varices.

DATA COLLECTION AND ANALYSIS

We performed a network meta-analysis with OpenBUGS using Bayesian methods and calculated the differences in treatments using hazard ratios (HR), odds ratios (OR), and rate ratios with 95% credible intervals (CrI) based on an available-case analysis, according to National Institute for Health and Care Excellence Decision Support Unit guidance. We performed the direct comparisons from randomised clinical trials using the same codes and the same technical details.

MAIN RESULTS

We included 66 randomised clinical trials (6653 participants) in the review. Sixty trials (6212 participants) provided data for one or more comparisons in the review. The trials that provided the information included people with cirrhosis due to varied aetiologies and those at high risk of bleeding from oesophageal varices. The follow-up in the trials that reported outcomes ranged from 6 months to 60 months. All but one of the trials were at high risk of bias. The interventions compared included beta-blockers, no active intervention, variceal band ligation, sclerotherapy, beta-blockers plus variceal band ligation, beta-blockers plus nitrates, nitrates, beta-blockers plus sclerotherapy, and portocaval shunt. Overall, 21.2% of participants who received non-selective beta-blockers ('beta-blockers') - the reference treatment (chosen because this was the most common treatment compared in the trials) - died during 8-month to 60-month follow-up. Based on low-certainty evidence, beta-blockers, variceal band ligation, sclerotherapy, and beta-blockers plus nitrates all had lower mortality versus no active intervention (beta-blockers: HR 0.49, 95% CrI 0.36 to 0.67; direct comparison HR: 0.59, 95% CrI 0.42 to 0.83; 10 trials, 1200 participants; variceal band ligation: HR 0.51, 95% CrI 0.35 to 0.74; direct comparison HR 0.49, 95% CrI 0.12 to 2.14; 3 trials, 355 participants; sclerotherapy: HR 0.66, 95% CrI 0.51 to 0.85; direct comparison HR 0.61, 95% CrI 0.41 to 0.90; 18 trials, 1666 participants; beta-blockers plus nitrates: HR 0.41, 95% CrI 0.20 to 0.85; no direct comparison). No trials reported health-related quality of life. Based on low-certainty evidence, variceal band ligation had a higher number of serious adverse events (number of events) than beta-blockers (rate ratio 10.49, 95% CrI 2.83 to 60.64; 1 trial, 168 participants). Based on low-certainty evidence, beta-blockers plus nitrates had a higher number of 'any adverse events (number of participants)' than beta-blockers alone (OR 3.41, 95% CrI 1.11 to 11.28; 1 trial, 57 participants). Based on low-certainty evidence, adverse events (number of events) were higher in sclerotherapy than in beta-blockers (rate ratio 2.49, 95% CrI 1.53 to 4.22; direct comparison rate ratio 2.47, 95% CrI 1.27 to 5.06; 2 trials, 90 participants), and in beta-blockers plus variceal band ligation than in beta-blockers (direct comparison rate ratio 1.72, 95% CrI 1.08 to 2.76; 1 trial, 140 participants). Based on low-certainty evidence, any variceal bleed was lower in beta-blockers plus variceal band ligation than in beta-blockers (direct comparison HR 0.21, 95% CrI 0.04 to 0.71; 1 trial, 173 participants). Based on low-certainty evidence, any variceal bleed was higher in nitrates than beta-blockers (direct comparison HR 6.40, 95% CrI 1.58 to 47.42; 1 trial, 52 participants). The evidence indicates considerable uncertainty about the effect of the interventions in the remaining comparisons.

AUTHORS' CONCLUSIONS

Based on low-certainty evidence, beta-blockers, variceal band ligation, sclerotherapy, and beta-blockers plus nitrates may decrease mortality compared to no intervention in people with high-risk oesophageal varices in people with cirrhosis and no previous history of bleeding. Based on low-certainty evidence, variceal band ligation may result in a higher number of serious adverse events than beta-blockers. The evidence indicates considerable uncertainty about the effect of beta-blockers versus variceal band ligation on variceal bleeding. The evidence also indicates considerable uncertainty about the effect of the interventions in most of the remaining comparisons.

Secondary prevention of variceal bleeding in adults with previous oesophageal variceal bleeding due to decompensated liver cirrhosis: a network meta-analysis

BACKGROUND

Approximately 40% to 95% of people with cirrhosis have oesophageal varices. About 15% to 20% of oesophageal varices bleed in about one to three years of diagnosis. Several different treatments are available, which include endoscopic sclerotherapy, variceal band ligation, beta-blockers, transjugular intrahepatic portosystemic shunt (TIPS), and surgical portocaval shunts, among others. However, there is uncertainty surrounding their individual and relative benefits and harms.

OBJECTIVES

To compare the benefits and harms of different initial treatments for secondary prevention of variceal bleeding in adults with previous oesophageal variceal bleeding due to decompensated liver cirrhosis through a network meta-analysis and to generate rankings of the different treatments for secondary prevention according to their safety and efficacy.

SEARCH METHODS

We searched CENTRAL, MEDLINE, Embase, Science Citation Index Expanded, World Health Organization International Clinical Trials Registry Platform, and trials registers until December 2019 to identify randomised clinical trials in people with cirrhosis and a previous history of bleeding from oesophageal varices.

SELECTION CRITERIA

We included only randomised clinical trials (irrespective of language, blinding, or status) in adults with cirrhosis and previous history of bleeding from oesophageal varices. We excluded randomised clinical trials in which participants had no previous history of bleeding from oesophageal varices, previous history of bleeding only from gastric varices, those who failed previous treatment (refractory bleeding), those who had acute bleeding at the time of treatment, and those who had previously undergone liver transplantation.

DATA COLLECTION AND ANALYSIS

We performed a network meta-analysis with OpenBUGS using Bayesian methods and calculated the differences in treatments using hazard ratios (HR), odds ratios (OR) and rate ratios with 95% credible intervals (CrI) based on an available-case analysis, according to National Institute of Health and Care Excellence Decision Support Unit guidance.

MAIN RESULTS

We included a total of 48 randomised clinical trials (3526 participants) in the review. Forty-six trials (3442 participants) were included in one or more comparisons. The trials that provided the information included people with cirrhosis due to varied aetiologies. The follow-up ranged from two months to 61 months. All the trials were at high risk of bias. A total of 12 interventions were compared in these trials (sclerotherapy, beta-blockers, variceal band ligation, beta-blockers plus sclerotherapy, no active intervention, TIPS (transjugular intrahepatic portosystemic shunt), beta-blockers plus nitrates, portocaval shunt, sclerotherapy plus variceal band ligation, beta-blockers plus nitrates plus variceal band ligation, beta-blockers plus variceal band ligation, sclerotherapy plus nitrates). Overall, 22.5% of the trial participants who received the reference treatment (chosen because this was the commonest treatment compared in the trials) of sclerotherapy died during the follow-up period ranging from two months to 61 months. There was considerable uncertainty in the effects of interventions on mortality. Accordingly, none of the interventions showed superiority over another. None of the trials reported health-related quality of life. Based on low-certainty evidence, variceal band ligation may result in fewer serious adverse events (number of people) than sclerotherapy (OR 0.19; 95% CrI 0.06 to 0.54; 1 trial; 100 participants). Based on low or very low-certainty evidence, the adverse events (number of participants) and adverse events (number of events) may be different across many comparisons; however, these differences are due to very small trials at high risk of bias showing large differences in some comparisons leading to many differences despite absence of direct evidence. Based on low-certainty evidence, TIPS may result in large decrease in symptomatic rebleed than variceal band ligation (HR 0.12; 95% CrI 0.03 to 0.41; 1 trial; 58 participants). Based on moderate-certainty evidence, any variceal rebleed was probably lower in sclerotherapy than in no active intervention (HR 0.62; 95% CrI 0.35 to 0.99, direct comparison HR 0.66; 95% CrI 0.11 to 3.13; 3 trials; 296 participants), beta-blockers plus sclerotherapy than sclerotherapy alone (HR 0.60; 95% CrI 0.37 to 0.95; direct comparison HR 0.50; 95% CrI 0.07 to 2.96; 4 trials; 231 participants); TIPS than sclerotherapy (HR 0.18; 95% CrI 0.08 to 0.38; direct comparison HR 0.22; 95% CrI 0.01 to 7.51; 2 trials; 109 participants), and in portocaval shunt than sclerotherapy (HR 0.21; 95% CrI 0.05 to 0.77; no direct comparison) groups. Based on low-certainty evidence, beta-blockers alone and TIPS might result in more, other compensation, events than sclerotherapy (rate ratio 2.37; 95% CrI 1.35 to 4.67; 1 trial; 65 participants and rate ratio 2.30; 95% CrI 1.20 to 4.65; 2 trials; 109 participants; low-certainty evidence). The evidence indicates considerable uncertainty about the effect of the interventions including those related to beta-blockers plus variceal band ligation in the remaining comparisons.

AUTHORS' CONCLUSIONS

The evidence indicates considerable uncertainty about the effect of the interventions on mortality. Variceal band ligation might result in fewer serious adverse events than sclerotherapy. TIPS might result in a large decrease in symptomatic rebleed than variceal band ligation. Sclerotherapy probably results in fewer 'any' variceal rebleeding than no active intervention. Beta-blockers plus sclerotherapy and TIPS probably result in fewer 'any' variceal rebleeding than sclerotherapy. Beta-blockers alone and TIPS might result in more other compensation events than sclerotherapy. The evidence indicates considerable uncertainty about the effect of the interventions in the remaining comparisons. Accordingly, high-quality randomised comparative clinical trials are needed.

Pathways of hepatic and renal damage through non-classical activation of the renin-angiotensin system in chronic liver disease

In liver cirrhosis, renin-angiotensin system (RAS) activation sustains renal sodium retention and hepatic fibrogenesis. New information has recently enlivened the traditional concept of RAS. For instance, renin and prorenin bind their ubiquitous receptors, resulting in the local production of angiotensin (Ang) II; increased serum calcium and calcimimetic agents, through stimulation of extracellular calcium-sensing receptors (CaSR), blunt renin production and lead to natriuretic effects in human and experimental cirrhosis. Alongside systemic production, there is Ang II tissue production within various organs through RAS enzymes different from angiotensin-converting enzyme (ACE), that is chymase, tissue plasminogen activator and several cathepsins. In experimental cirrhosis, inhibition of chymase leads to natriuretic and hepatic antifibrotic effects, without changes in systemic haemodynamics. In the kidney, local RAS coordinates proximal and distal tubular sodium reabsorption. However, renalase, whose plasma and tissue levels are severely altered in experimental cirrhosis, degrades systemic and renal tubule catecholamines, antagonizing the effects of renal RAS. Angiotensinogen-derived natriuretic and vasodilating peptides (Ang1-9, Ang1-7, Ang3-8) and their receptors have been described. Receptor agonists or antagonists are available to affect portal hypertension and sodium retention in cirrhosis. ACE2-dependent generation of Ang1-7 may inhibit experimental liver fibrosis. inhibition of Ang1-7 clearance by means of neprilysin blockade has portal hypotensive and natriuretic effects. Ang1-12, whose production renin does not regulate, is converted to several different angiotensin peptides via chymase. Finally, Ang II behaves as either an antinatriuretic or a natriuretic agent, based on the tissue content of AT₁ R and AT₂ R receptors, their ratio being prone to pharmacological modulation.

Future Pharmacological Therapies of Portal Hypertension

PURPOSE OF REVIEW

To provide an overview of recent pharmacological treatments for portal hypertension evaluated in early clinical trials, with particular emphasis on the pathophysiological basis of their use.

RECENT FINDINGS

In patients with compensated cirrhosis, even small decreases in portal pressure (as small as 1 mmHg) are associated with a lower probability of decompensation. In patients with decompensated cirrhosis, portal pressure "response" to non-selective beta-blocker (NSBB) therapy is associated with a lower mortality. When present, significant portal hypertension persists even after elimination of the etiology of cirrhosis and this justifies the continued development of new drugs that target portal hypertension.

SUMMARY

Over several decades we have gained great depth in the understanding of portal hypertension, its mechanisms and complications. NSBBs, which act by reducing portal venous inflow (an extrahepatic target), are effective in reducing portal pressure and have been the mainstay of therapy for portal hypertension in the last 35 years -being effective in preventing decompensation and variceal hemorrhage. However, because not all patients will have a sufficient response to NSBB and some may be intolerant to NSBB, alternative drugs or drugs that will augment the effect of NSBB on portal pressure are being tested in pre-clinical and early-clinical trials. Many of these drugs target more than one of the intrahepatic or extrahepatic mechanisms implicated in the pathogenesis of portal hypertension in cirrhosis. Out of these proposed therapies, statins have emerged as the most promising new pharmacological therapy for the treatment of portal hypertension.

Angiotensin II receptor blockers for the treatment of portal hypertension in patients with liver cirrhosis: a systematic review and meta-analysis of randomized controlled trials

BACKGROUND

Randomized controlled trials (RCTs) showed inconsistent results regarding the efficacy of angiotensin II receptor blockers (ARBs) on portal pressure as indicated by hepatic venous pressure gradient (HVPG).

METHODS

A meta-analysis of RCTs was performed to evaluate the influence of ARBs treatment on HVPG. PubMed, Embase, and Cochrane's Library were searched for relevant RCTs. A fixed or a randomized effect model was used to pool the results according the heterogeneity. Subgroup analyses were performed to explore the source of heterogeneity.

RESULTS

Eleven RCTs with 394 patients were included. ARBs treatment did not significantly change HVPG as compared with controls (weighted mean difference [WMD] = -0.63, 95% confidence interval [CI] -1.73 to 0.47 mmHg, p = 0.26; I2 = 60%). These results were consistent in studies comparing ARBs with propranolol (WMD = -0.40, 95% CI -2.22 to 1.41 mmHg, p = 0.67; I2 = 68%), and those comparing ARBs with non-active controls including placebo or no treatment (WMD = -1.05, 95% CI -2.33 to 0.24 mmHg, p = 0.13; I2 = 44%). These results were also not affected by the individual ARBs used. Moreover, treatment of ARBs significantly reduced mean arterial blood pressure (WMD = -6.12, 95% CI -9.69 to -2.55 mmHg, p = 0.008; I2 = 53%), and the risk of symptomatic hypotension was increased (RR = 4.13, 95% CI 0.94 to 18.18, p = 0.06; I2 = 0%).

CONCLUSIONS

ARBs did not reduce portal pressure in patients with cirrhosis; moreover, the risk of symptomatic hypotension may increase.

Role of the renin-angiotensin system in hepatic fibrosis and portal hypertension

The renin-angiotensin system (RAS) is an important regulator of cirrhosis and portal hypertension. As hepatic fibrosis progresses, levels of the RAS components angiotensin (Ang) II, Ang-(1-7), angiotensin-converting enzyme (ACE), and Ang II type 1 receptor (AT1R) are increased. The primary effector Ang II regulates vasoconstriction, sodium homoeostasis, fibrosis, cell proliferation, and inflammation in various diseases, including liver cirrhosis, through the ACE/Ang II/AT1R axis in the classical RAS. The ACE2/Ang-(1-7)/Mas receptor and ACE2/Ang-(1-9)/AT2R axes make up the alternative RAS and promote vasodilation, antigrowth, proapoptotic, and anti-inflammatory effects; thus, countering the effects of the classical RAS axis to reduce hepatic fibrogenesis and portal hypertension. Patients with portal hypertension have been treated with RAS antagonists such as ACE inhibitors, Ang receptor blockers, and aldosterone antagonists, with very promising hemodynamic results. In this review, we examine the RAS, its roles in hepatic fibrosis and portal hypertension, and current therapeutic approaches based on the use of RAS antagonists in patients with portal hypertension.

Use of inhibitors of the renin-angiotensin system is associated with longer survival in patients with hepatocellular carcinoma

BACKGROUND

Inhibition of the renin-angiotensin system (RAS) was associated with longer survival in patients with different solid malignancies.

OBJECTIVE

The objective of this study was to investigate the effect of RAS inhibitor (RASi) treatment (angiotensin-converting enzyme inhibitors or angiotensin-II-receptor blockers) on survival of patients with hepatocellular carcinoma (HCC).

METHODS

Patients diagnosed with HCC and Child-Pugh A between 1992 and 2013 who received sorafenib, experimental therapy, or best supportive care were eligible for the Vienna cohort. The Mainz cohort included patients with HCC and Child-Pugh A who received sorafenib treatment between 2007 and 2016. The association between RASi and overall survival (OS) was evaluated in univariate and multivariate analyses.

RESULTS

In the Vienna cohort, 43 of 156 patients received RASi for hypertension. RASi treatment was associated with longer OS (11.9 vs. 6.8 months (mo); p = 0.014) and remained a significant prognostic factor upon multivariate analysis (HR = 0.6; 95% CI 0.4-0.9; p = 0.011). In subgroup analysis, patients treated with sorafenib plus RASi had better median OS (19.5 mo) compared to those treated with either sorafenib (10.9 mo) or RASi (9.7 mo) alone (p = 0.043). The beneficial effect of RASi on survival was confirmed in the Mainz cohort (n = 76).

CONCLUSION

RAS inhibition is associated with longer survival in HCC patients with Child-Pugh class A.

Hemodynamic effects of renin-angiotensin-aldosterone inhibitor and β-blocker combination therapy vs. β-blocker monotherapy for portal hypertension in cirrhosis: A meta-analysis

β-blockers are commonly used for the treatment of acute variceal bleeding in cirrhosis. Renin-angiotensin-aldosterone antagonists (angiotensin I-converting enzyme inhibitors, angiotensin receptor blockers and aldosterone antagonists) are potential therapies for portal hypertension. Several studies have compared the renin-angiotensin-aldosterone system (RAAS) inhibitor and β-blocker combination therapy vs. β-blocker monotherapy, with inconsistent results. The aim of the present study was to assess the efficacy of the RAAS inhibitor and β-blocker combination therapy vs. β-blocker monotherapy for hepatic vein pressure gradient (HVPG) reduction in cirrhosis. Studies were obtained using PubMed, Embase, Medline and Cochrane library databases up to July 2015, and the weighted mean difference (WMD) in HVPG reduction was used as a measure of treatment efficacy. In total, three studies (91 patients) were included. When compared to the β-blocker monotherapy, the RAAS inhibitor and β-blocker combination therapy resulted in a significant HVPG reduction [WMD 1.70; 95% confidence interval (CI): 0.52-2.88]. However, there was no significant difference in the heart rate reduction between the monotherapy and combination therapy groups (WMD -0.11; 95% CI: -3.51-3.29). In addition, no significant difference in the hemodynamic response was observed between the two groups (WMD 1.46; 95% CI: 0.93-2.30). In conclusion, the RAAS inhibitor and β-blocker combination therapy reduces portal hypertension significantly and to a greater extent than β-blocker monotherapy. Both therapies reduced the heart rate to similar levels; however, the RAAS inhibitor and β-blocker combination therapy reduced the mean arterial pressure to a greater extent. Due to the limited number of studies included, the data available do not allow a satisfactory comparison of adverse events. Moreover, further larger-scale trials are required in order to strengthen the results of the present study.

Mechanisms, Management, and Treatment of Fibrosis in Patients With Inflammatory Bowel Diseases

In the last 10 years, we have learned much about the pathogenesis, diagnosis, and management of intestinal fibrosis in patients with inflammatory bowel diseases. Just a decade ago, intestinal strictures were considered to be an inevitable consequence of long-term inflammation in patients who did not respond to anti-inflammatory therapies. Inflammatory bowel diseases-associated fibrosis was seen as an irreversible process that frequently led to intestinal obstructions requiring surgical intervention. This paradigm has changed rapidly, due to the antifibrotic approaches that may become available. We review the mechanisms and diagnosis of this serious complication of inflammatory bowel diseases, as well as factors that predict its progression and management strategies.

β-2 Adrenergic receptor gene polymorphism and response to propranolol in cirrhosis

AIM: To evaluate the association of β-2 adrenergic receptor (β₂-AR) gene polymorphism with response of variceal pressure to propranolol in cirrhosis.

METHODS: Sixty-four non-related cirrhotic patients participated in this study and accepted variceal pressure measurement before and after propranolol administration. Polymorphism of the β₂-AR gene was determined by directly sequencing of the polymerase chain reaction products from the DNA samples that were prepared from the patients.

RESULTS: The prevalence of Gly16-Glu/Gln27 and Arg16-Gln27 homozygotes, and compound heterozygotes was 29.7%, 10.9%, and 59.4%, respectively. Patients with cirrhosis with Gly16-Glu/Gln27 homozygotes had a greater decrease of variceal pressure after propranolol administration than those with Arg16-Gln27 homozygotes or with compound heterozygotes (22.4% ± 2.1%, 13.1% ± 2.7% and 12.5% ± 3.1%, respectively, P < 0.01).

CONCLUSION: The variceal pressure response to propranolol was associated with polymorphism of β₂-AR gene. Patients with the Gly¹⁶-Glu/Gln²⁷ homozygotes probably benefit from propranolol therapy.

Effects of candesartan and propranolol combination therapy versus propranolol monotherapy in reducing portal hypertension

BACKGROUND/AIMS

Angiotensin receptor blockers (ARBs) inhibit activated hepatic stellate cell contraction and are thought to reduce the dynamic portion of intrahepatic resistance. This study compared the effects of combined treatment using the ARB candesartan and propranolol versus propranolol monotherapy on portal pressure in patients with cirrhosis in a prospective, randomized controlled trial.

METHODS

Between January 2008 and July 2009, 53 cirrhotic patients with clinically significant portal hypertension were randomized to receive either candesartan and propranolol combination therapy (26 patients) or propranolol monotherapy (27 patients). Before and 3 months after the administration of the planned medication, the hepatic venous pressure gradient (HVPG) was assessed in both groups. The dose of propranolol was subsequently increased from 20 mg bid until the target heart rate was reached, and the candesartan dose was fixed at 8 mg qd. The primary endpoint was the HVPG response rate; patients with an HVPG reduction of >20% of the baseline value or to <12 mmHg were defined as responders.

RESULTS

The mean portal pressure declined significantly in both groups, from 16 mmHg (range, 12-28 mmHg) to 13.5 mmHg (range, 6-20 mmHg) in the combination group (P<0.05), and from 17 mmHg (range, 12-27 mmHg) to 14 mmHg (range, 7-25 mmHg) in the propranolol monotherapy group (P<0.05). However, the medication-induced pressure reduction did not differ significantly between the two groups [3.5 mmHg (range, -3-11 mmHg) vs. 3 mmHg (range, -8-10 mmHg), P = 0.674]. The response rate (55.6% vs. 61.5%, P = 0.435) and the reductions in mean blood pressure or heart rate also did not differ significantly between the combination and monotherapy groups.

CONCLUSIONS

The addition of candesartan (an ARB) to propranolol confers no benefit relative to classical propranolol monotherapy for the treatment of portal hypertension, and is thus not recommended.

Medical therapy of stricturing Crohn's disease: what the gut can learn from other organs - a systematic review

Crohn’s disease (CD) is a chronic remitting and relapsing disease. Fibrostenosing complications such as intestinal strictures, stenosis and ultimately obstruction are some of its most common long-term complications. Despite recent advances in the pathophysiological understanding of CD and a significant improvement of anti-inflammatory therapeutics, medical therapy for stricturing CD is still inadequate. No specific anti-fibrotic therapy exists and the incidence rate of strictures has essentially remained unchanged. Therefore, the current therapy of established fibrotic strictures comprises mainly endoscopic dilation as well as surgical approaches. However, these treatment options are associated with major complications as well as high recurrence rates. Thus, a specific anti-fibrotic therapy for CD is urgently needed. Importantly, there is now a growing body of evidence for prevention as well as effective medical treatment of fibrotic diseases of other organs such as the skin, lung, kidney and liver. In face of the similarity of molecular mechanisms of fibrogenesis across these organs, translation of therapeutic approaches from other fibrotic diseases to the intestine appears to be a promising treatment strategy. In particular transforming growth factor beta (TGF-β) neutralization, selective tyrosine kinase inhibitors, blockade of components of the renin-angiotensin system, IL-13 inhibitors and mammalian target of rapamycin (mTOR) inhibitors have emerged as potential drug candidates for anti-fibrotic therapy and may retard progression or even reverse established intestinal fibrosis. However, major challenges have to be overcome in the translation of novel anti-fibrotics into intestinal fibrosis therapy, such as the development of appropriate biomarkers that predict the development and accurately monitor therapeutic responses. Future clinical studies are a prerequisite to evaluate the optimal timing for anti-fibrotic treatment approaches, to elucidate the best routes of application, and to evaluate the potential of drug candidates to reach the ultimate goal: the prevention or reversal of established fibrosis and strictures in CD patients.

Involvement of the HIF-1α and Wnt/β-catenin pathways in the protective effects of losartan on fatty liver graft with ischaemia/reperfusion injury

Besides cardioprotective effects, the AT1R (angiotensin-II type 1 receptor) antagonist losartan protects the liver from IRI [IR (ischaemia/reperfusion) injury], but the mechanism has not been fully determined. The HIF (hypoxia inducible factor)-1α and Wnt/β-catenin signalling pathways have been reported to be involved in the mechanism of liver IRI. Therefore the aim of the present study was to determine whether the Wnt/HIF axis is part of the mechanism of the positive effect of AngII inhibition by losartan in liver IRI in rats. Various measurements were made in MCD/HF-NASH (methionine- and choline-deficient-diet/high-fat-diet-induced non-alcoholic steatohepatitis) rats with liver IRI. Acute losartan pre-administration markedly reversed the IR-suppressed levels of the hepatic-protective factors IL (interleukin)-6, IFN (interferon)-γ, Wnt3a, β-catenin and HIF-1α, and decreased hepatic blood flow and IR-elevated serum ALT (alanine aminotransferase), hepatic TNF (tumour necrosis factor)-α, IL-1α, hepatic congestion, vacuolization and necrosis, hepatic Suzuki IRI scores, necrotic index and levels of TBARS (thiobarbituric acid-reacting substances) in MCD/HF-NASH rats. Furthermore, acute Wnt3a pre-treatment significantly inhibited IR-elevated serum ALT, hepatic Suzuki IRI scores and TBARS, and restored the IR-depleted β-catenin/HIF-1α activity in MCD/HF-NASH rats. Simultaneous acute sFRP2 (secreted frizzled-related protein 2; a Wnt3a inhibitor) pre-treatment eliminated the losartan-related beneficial effects in MCD/HF-NASH rats with liver IRI, which was accompanied by a decrease in hepatic HIF-1α/β-catenin activity. Losartan-induced up-regulation of HIF-1α and Wnt/β-catenin signalling was associated with the recovery of IR-inhibited hepatic Bcl-2, Mn-SOD (manganese superoxide), Cu/Zn-SOD (copper/zinc superoxide) and GSH levels, and the suppression of IR-increased hepatic catalase and caspase 3/caspase 8 levels in MCD/HF-NASH rats. In conclusion, up-regulation of the HIF-1α and Wnt/β-catenin signalling pathways are part of the mechanism of the positive effects of losartan-related AngII inhibition in MCD/HF-NASH rats with liver IRI. Our study highlights the potential of the dual-organ protective agent losartan in NASH patients with steatotic livers and cardiovascular risk.

Comparative randomized study on efficacy of losartan versus propranolol in lowering portal pressure in decompensated chronic liver disease

OBJECTIVE

This study aimed to compare the efficacy of losartan, an angiotensin II receptor antagonist, with propranolol on portal hypertension in patients with decompensated chronic liver disease.

METHODS

In all, 30 patients with Child-Pugh B cirrhosis and large varices without any prior therapy for portal hypertension were randomized to either losartan (n = 15) or propranolol (n = 15). Clinical, biochemical and hemodynamic parameters including hepatic venous pressure gradient (HVPG), wedged hepatic venous pressure (WHVP), mean arterial blood pressure (MABP) and free hepatic venous pressure (FHVP) were measured at baseline and after 4-week therapy. Patients with HVPG < 12 mmHg were regarded as responders.

RESULTS

An equal number of responders were seen in both groups (6/15, 40.0%). The reduction of WHVP and HVPG was greater in the losartan group than in the propranolol group, although no significant differences between them were found. Heart rate decreased more in the propranolol arm than in the losartan arm (P < 0.01); however, no correlation between the decrease of heart rate and the reduction of HVPG was observed. One patient in the losartan group, although a responder, had gastrointestinal bleeding 2 months after the drug administration, but the varices were small under endoscopy and did not require definitive therapy. The fall of MABP was greater with losartan, with no statistical difference between the two groups.

CONCLUSION

The effect of losartan was comparable to propranolol in reducing portal pressure in decompensated Child-Pugh B chronic liver disease.

Comparison of hepatic venous pressure gradient and two models of end-stage liver disease for predicting the survival in patients with decompensated liver cirrhosis

GOALS

We evaluated the efficacy of initial and follow-up hepatic venous pressure gradient (HVPG), models of end-stage liver disease (MELD), and MELD-Na for predicting the survival of patients with decompensated liver cirrhosis (LC).

BACKGROUND

MELD with/without Na score and HVPG have been important predictors of mortality in patients with LC.

STUDY

Between January 2006 and 2011, a total of 57 patients with decompensated LC, all of whom underwent >2 HVPG measurements for the confirmation of propranolol dosing, were enrolled. MELD and MELD-Na scores were calculated on the day of HVPG measurement. The prognostic accuracy of the initial and follow-up HVPG, MELD, and MELD-Na were analyzed, and independent factors for mortality were evaluated.

RESULTS

Ten patients (17.5%) died from LC. Initial HVPG (0.883), initial MELD-Na (0.877), follow-up HVPG (0.829), and follow-up MELD-Na (0.802) showed good area under the receiver operating characteristic curve scores in predicting 1-year mortality. In predicting 2-year mortality, only follow-up HVPG (0.821, cut-off value 18 mm Hg) showed good score. Overall area under the receiver operating characteristic curves (initial and follow-up) were 0.843 and 0.864 in HVPG, 0.721 and 0.674 in MELD, and 0.762 and 0.715 in MELD-Na, respectively. In the Cox regression analysis, only follow-up HVPG (P=0.02; odds ratio, 1.11) was associated with mortality.

CONCLUSIONS

The efficacy of HVPG for predicting mortality is excellent compared with that of MELD or MELD-Na. Therefore, aside from the confirmation of adequate propranolol dosing, HVPG may be needed for predicting the survival of patients with decompensated LC.

Quantitative modeling of the physiology of ascites in portal hypertension

Although the factors involved in cirrhotic ascites have been studied for a century, a number of observations are not understood, including the action of diuretics in the treatment of ascites and the ability of the plasma-ascitic albumin gradient to diagnose portal hypertension. This communication presents an explanation of ascites based solely on pathophysiological alterations within the peritoneal cavity. A quantitative model is described based on experimental vascular and intraperitoneal pressures, lymph flow, and peritoneal space compliance. The model's predictions accurately mimic clinical observations in ascites, including the magnitude and time course of changes observed following paracentesis or diuretic therapy.

Effects of 1-year administration of olmesartan on portal pressure and TGF-beta1 in selected patients with cirrhosis: a randomized controlled trial

BACKGROUND

The renin-angiotensin system plays an important role in hepatic fibrosis and portal hypertension. We evaluated the long-term effects of olmesartan, an angiotensin type 1 (AT1) receptor blocker, on hemodynamics and liver fibrosis.

METHODS

Forty-eight selected patients with cirrhosis were randomly divided into two groups of 24 patients each, those who received and those who did not receive olmesartan treatment for 1 year. Hepatic hemodynamic studies, and measurements of transforming growth factor-beta1 (TGF-beta1) and blood markers of hepatic fibrosis, including serum hyaluronic acid (HA), type IV collagen, and procollagen III N-terminal propeptide levels, were also performed at the beginning and end of the study.

RESULTS

The median dose of the final drug administration was 20 mg (range 10-40 mg). Olmesartan reduced the hepatic venous pressure gradient (HVPG) by -12.9 ± 9.1% (p = 0.035) after 1 year. No significant changes were seen in controls. Six of the 24 patients (25%) in the olmesartan group showed a >20% reduction of HVPG from baseline values. TGF-beta1 was significantly decreased in patients who received olmesartan (7.0 ± 8.2 vs. 3.1 ± 1.6 ng/mL, p = 0.046) but there was no decrease in the controls. A significant trend was shown by correlating HA and TGF-beta1 variations in cirrhosis patients (p = 0.018, r = 0.377). Fibrosis markers were unchanged at the end of the study in both groups.

CONCLUSIONS

Olmesartan induced a mild reduction of portal pressure and TGF-beta1 for 1 year, but did not suppress hepatic fibrosis markers.

[Treatment update on portal hypertension and complications]

Current understanding of the pathophysiology of portal hypertension has resulted in therapeutic approaches aimed at correcting the increased splanchnic blood flow and some of which have been already used in clinical practice. Recently new perspectives opened and erstwhile paradigm has been changed to focus on increased resistance to portal blood flow and the formation of portosystemic collateralization. Several studies revealed the clear-cut mechanisms of hepatic endothelial dysfunction and abnormal angiogenesis contributing to the development of portal hypertension. Thus the modulations of hyperdynamic circulation or angiogenesis seem to be valuable therapeutic targets. In the current review update, we discuss the multidisciplinary management of modulating hepatic vascular resistance and abnormal angiogenesis associated with portal hypertension. However, these new pharmacological approaches are still under investigation and widescale clinical application are needed to develop effective strategies.

Renin-angiotensin-aldosterone inhibitors in the reduction of portal pressure: a systematic review and meta-analysis

BACKGROUND & AIMS

Renin-angiotensin-aldosterone antagonists [ACE inhibitors (ACEi), angiotensin receptor blockers (ARB), aldosterone antagonists (AA)] are potential therapies for portal hypertension. We evaluated the efficacy and safety of RAAS inhibitors in hepatic venous pressure gradient (HVPG) reduction.

METHODS

We included full-text controlled trials in patients with cirrhosis and portal hypertension. The primary outcome was mean change in HVPG between treatment and control. Two independent reviewers performed trial selection and quality assessment. An individual patient meta-analysis based on the data of three studies was performed.

RESULTS

From 193 citations, 19 controlled trials (n=678) were included. When compared to placebo, ARB/ACEi resulted in significant HVPG reduction. The best quality trials compared ARB/ACEi to beta-blockers (BB). Pooled individual patient data for three of four of these trials showed that BB decreased the HVPG more than ARB/ACEi. In patients with Child Pugh A cirrhosis, the HVPG reduction with ARB/ACEi (-17%; 95% CI: -28 to -6), was similar to that of BB (-21%; 95% CI: -32 to -9). Significant variation in the comparison groups of AA trials precluded pooling. There was no difference in adverse events in any group but selected studies noted adverse hemodynamic effects in decompensated patients on ARB/ACEi.

CONCLUSIONS

ARB/ACEi reduce portal pressure in patients with Child Pugh A cirrhosis without adverse events. The efficacy and safety in this group may be secondary to a targeted effect on the local hepatic RAAS system, as compared to decompensated patients who risk hypotension and renal insufficiency due to activation of the systemic RAAS. Further studies should determine the potential of these drugs as an alternative or adjunct to BB.

Losartan prevents portal hypertension-induced, redox-mediated endothelial dysfunction in the mesenteric artery in rats

BACKGROUND & AIMS

Advanced stages of portal hypertension are characterized by generalized vasodilatation and a hyperdynamic syndrome that leads to complications such as hepatopulmonary syndrome. We assessed the endothelial function--particularly the formation of nitric oxide (NO) and endothelium-derived hyperpolarizing factor (EDHF)--in rats following common bile duct ligation (CBDL) to determine the underlying mechanisms of these processes.

METHODS

Reactivity of mesenteric artery rings from male Wistar rats was determined in organ chambers. The expression levels of connexins (Cx) (Cx37, Cx40, Cx43), intermediate and small conductance Ca(2+)-activated K(+) channels (IK(Ca), SK(Ca)), endothelial NO synthase (eNOS), NADPH oxidase subunits, and nitrotyrosines were assessed by immunohistochemistry in mesenteric and pulmonary arteries. The vascular formation of reactive oxygen species (ROS) was evaluated using dihydroethidine. Control rats or those that had undergone CBDL were given either the NADPH oxidase inhibitor apocynin or the angiotensin II receptor type 1 antagonist losartan.

RESULTS

Decreased EDHF-mediated relaxations to acetylcholine and red wine polyphenols were observed in CBDL rats, compared with controls, whereas the level of NO-mediated relaxation was similar. Impaired EDHF-mediated relaxations were associated with reduced vascular expression of Cx37, Cx40, Cx43, IK(Ca) and SK(Ca); increased expression of eNOS and NADPH oxidase subunits; and increased vascular formation of ROS and peroxynitrites. These effects were prevented by exposure to apocynin or losartan.

CONCLUSIONS

CBDL is associated with reduced EDHF-mediated relaxations in the mesenteric artery, whereas NO-mediated relaxations persisted. These findings indicate that impaired EDHF-mediated relaxation involves an excessive vascular oxidative stress, most likely following activation of angiotensin II type 1 receptors.

Current and future anti-fibrotic therapies for chronic liver disease

Chronic injury results in a wound healing response that eventually leads to fibrosis. The response is generalized, with features common among multiple organ systems. In the liver, various different types of injury lead to fibrogenesis, implying a common pathogenesis. Although several specific therapies for patients who have different liver diseases have been successfully developed, including antiviral therapies for those who have hepatitis B and hepatitis C virus infection, specific and effective antifibrotic therapy remains elusive. Over the past 2 decades, great advances in the understanding of fibrosis have been made and multiple mechanisms underlying hepatic fibrogenesis uncovered. Elucidation of these mechanisms has been of fundamental importance in highlighting novel potential therapies. Preclinical studies have indicated several putative therapies that might abrogate fibrogenesis. This article emphasizes mechanisms underlying fibrogenesis and reviews available and future therapeutics.

Irbesartan plus low-dose propranolol versus low-dose propranolol alone in cirrhosis: a placebo-controlled, double-blind study

OBJECTIVES

Angiotensin II receptor antagonists have been shown to moderately lower portal pressure in some patients with cirrhosis but may have adverse effects on kidney function. This study aimed at comparing the effects of a combined treatment using irbesartan plus propranolol with propranolol monotherapy on portal pressure and kidney function in patients with cirrhosis.

METHODS

Thirty-two patients were included (Child A/B/C: 13/18/1, etiology: 16 alcohol, 13 viral, 3 other; bilirubin 1.4 +/- 1.1 mg/dL, creatinine 0.86 +/- 0.20 mg/dL, baseline hepatic venous pressure gradient 18.7 +/- 5.3 mmHg). All patients received 20 mg propranolol b.i.d. Additionally, they randomly received either placebo (N = 15) or irbesartan (step-up dosage titration up to 300 mg/d, N = 17). Patients were followed at weekly intervals, re-evaluation of hepatic venous pressure gradient (HVPG) was performed after 8 wk.

RESULTS

One patient in the propranolol/irbesartan group was excluded due to variceal bleeding. No other adverse events occurred. Portal pressure declined in both groups (propranolol/irbesartan group 19.6 +/- 1.5 mmHg to 16.6 +/- 1.2 mmHg, P= 0.037, propranolol/placebo group 17.8 +/- 1.1 mmHg to 15.1 +/- 1.2 mmHg, P= 0.019). Sodium excretion significantly increased in the propranolol/irbesartan group (from 122 +/- 20 mmol/d to 230 +/- 23 mmol/d, P= 0.045), but not in the propranolol/placebo group.

CONCLUSIONS

Combination treatment of propranolol plus irbesartan is well tolerated in cirrhotic patients when titrating the angiotensin II antagonist in a step-up manner, and it increases sodium excretion in patients with compensated or moderately decompensated cirrhosis. Addition of irbesartan has no effect on portal pressure.

Acute variceal bleeding: pharmacological treatment and primary/secondary prophylaxis

Variceal bleeding is one of the most severe complications of portal hypertension related to liver cirrhosis. Primary prophylaxis is considered mandatory in patients with cirrhosis and high-risk oesophageal varices, and once varices have bled, every effort should be made to arrest the haemorrhage and prevent further bleeding episodes. In acute variceal bleeding, vasoactive drugs that lower portal pressure should be started even before endoscopy, and should be maintained for up to 5 days. The choice of vasoactive drug should be made according to local resources. Terlipressin, somatostatin and octreotide can be used; vasopressin plus transdermal nitroglycerin may be used if no other drug is available. In variceal bleeding, antibiotic therapy is also mandatory. In primary and secondary prophylaxis, beta-blockers are the mainstay of therapy. In secondary prophylaxis (but not in primary prophylaxis) these drugs can be combined with organic nitrates.

Addressing liver fibrosis with liposomes targeted to hepatic stellate cells

Liver fibrosis is a chronic disease that results from hepatitis B and C infections, alcohol abuse or metabolic and genetic disorders. Ultimately, progression of fibrosis leads to cirrhosis, a stage of the disease characterized by failure of the normal liver functions. Currently, the treatment of liver fibrosis is mainly based on the removal of the underlying cause of the disease and liver transplantation, which is the only treatment for patients with advanced fibrosis. Hepatic stellate cells (HSC) are considered to be key players in the development of liver fibrosis. Chronically activated HSC produces large amounts of extracellular matrix and enhance fibrosis by secreting a broad spectrum of cytokines that exert pro-fibrotic actions in other cells, and in an autocrine manner perpetuate their own activation. Therefore, therapeutic interventions that inhibit activation of HSC and its pro-fibrotic activities are currently under investigation worldwide. In the present study we applied targeted liposomes as drug carriers to HSC in the fibrotic liver and explored the potential of these liposomes in antifibrotic therapies. Moreover, we investigated effects of bioactive compounds delivered by these liposomes on the progression of liver fibrosis. To our knowledge, this is the first study demonstrating that lipid-based drug carriers can be selectively delivered to HSC in the fibrotic liver. By incorporating the bioactive lipid DLPC, these liposomes can modulate different processes such as inflammation and fibrogenesis in the fibrotic liver. This dual functionality of liposomes as a drug carrier system with intrinsic biological effects may be exploited in new approaches to treat liver fibrosis.

Effect of propranolol on portal pressure and systemic hemodynamics in patients with liver cirrhosis and portal hypertension: a prospective study

BACKGROUND/AIMS

Propranolol can prevent variceal bleeding by ameliorating portal hypertension. We conducted this study to determine the effect of propranolol on portal hypertension and the optimal required dose in Korean cirrhotic patients.

METHODS

This study prospectively evaluated 50 patients with cirrhosis who exhibited variceal bleeding. The hepatic venous pressure gradient (HVPG), portal venous flow, heart rate (HR), and blood pressure were assessed both at baseline and at 3 months after the treatment. The initial dose of propranolol (20 mg) was subsequently adjusted until the target HR was reached. Patients in whom HVPG reduced by >20% or to less than 12 mmHg were defined as responders.

RESULTS

Propranolol significantly (p<0.01) reduced the HVPG (-21+/-26%, mean+/-standard deviation), portal venous flow (-25+/-21%), HR (-20+/-13%), and blood pressure (-3+/-13%). Twenty-nine patients were responders, and the optimal required dose was 154.4 mg. The main complication was dizziness (24%), but this was not serious enough to require medication withdrawal.

CONCLUSIONS

Propranolol is safe and effective at reducing portal pressure in Korean cirrhotic patients. An effective improvement in portal hypertension requires the dose to be increased until the target HR is reached.

New angiotensin II type 1 receptor blocker olmesartan improves portal hypertension in patients with cirrhosis

AIM

To evaluate the effect of the new oral angiotensin II type 1 receptor blocker olmesartan on portal hemodynamics in patients with cirrhosis.

METHODS

From January 2005 to March 2006, 18 cirrhosis patients treated with endoscopic band ligation for primary esophageal variceal bleeding were included in the present study. Hepatic venous pressure gradient (HVPG) of the patients was >/=12 mmHg at baseline measurement. The patients were given 10 mg olmesartan orally once daily for 2 weeks. Eighteen cirrhosis patients with esophageal variceal bleeding who did not receive any antihypertensive agents were included in the study as control. On day 14, HVPG, blood pressure, heart rate, and parameters of hepatic and renal function were examined after the treatment. Responders were defined as those with HVPG reduction of >20% versus baseline.

RESULTS

Olmesartan significantly reduced HVPG by -16.8 +/- 22.0% (P = 0.031) and mean arterial pressure by -13.1 +/- 10.8% (P = 0.0041). Six of 18 (33.3%) patients in the olmesartan group showed >20% reduction of HVPG from baseline values. None of the patients treated with olmesartan had any complications.

CONCLUSION

Olmesartan reduces portal pressure and may be safe and highly effective in the treatment of portal hypertension.

AT1 receptor antagonist Candesartan in selected cirrhotic patients: effect on portal pressure and liver fibrosis markers

BACKGROUND/AIMS

The renin-angiotensin system plays an important role in hepatic fibrogenesis and in portal hypertension. To examine the long-term effects of Candesartan cilexetil, an angiotensin type 1 (AT1) receptor blocker, on portal-systemic haemodynamics and on liver fibrosis.

METHODS

Forty-seven compensated Child A and Child B (8) cirrhotic patients were randomly assigned to receive Candesartan cilexetil, 8 mg/d (N.24) and no treatment (N.23) for 1 year. Portal-systemic haemodynamic parameters, serological levels of procollagen (PIIINP), hyaluronic acid (HA) and transforming growth factor beta 1 (TGFbeta1) were assessed at baseline and after 12 months.

RESULTS

No patients discontinued or decreased the drug. The hepatic venous pressure gradient (HVPG) decreased significantly in treated patients (-8.4%+/-2.4) with a reduction >20% in 25% of cases vs+5.6%+/-2.9 in the untreated group. HA plasma levels decreased significantly in Candesartan treated patients in whom HVPG diminished and rose in untreated patients in whom HVPG increased.

CONCLUSIONS

In selected cirrhotic patients, pharmacological inhibition of the AT1 receptor is well tolerated and induced a mild reduction of portal pressure. This haemodynamic effect might be related to liver fibrogenesis activity.

Effects of six months losartan administration on liver fibrosis in chronic hepatitis C patients: a pilot study

AIM

To evaluate the safety and efficacy of chronic administration of losartan on hepatic fibrosis in chronic hepatitis C patients.

METHODS

Fourteen patients with chronic hepatitis C non-responders (n = 10), with contraindications (n = 2) or lack of compliance (n = 2) to interferon plus ribavirin therapy and liver fibrosis were enrolled. Liver and renal function test, clinical evaluation, and liver biopsies were performed at baseline and after losartan administration at a dose of 50 mg/d during the 6 mo. The control group composed of nine patients with the same inclusion criteria and paired liver biopsies (interval 6-14 mo). Histological activity index (HAI) with fibrosis stage was assessed under blind conditions by means of Ishak's score. Subendothelial fibrosis was evaluated by digital image analyses.

RESULTS

The changes in the fibrosis stage were significantly different between losartan group (decrease of 0.5+/-1.3) and controls (increase of 0.89+/-1.27; P<0.03). In the treated patients, a decrease in fibrosis stage was observed in 7/14 patients vs 1/9 control patients (P<0.04). A decrease in sub-endothelial fibrosis was observed in the losartan group. No differences were found in HAI after losartan administration. Acute and chronic decreases in systolic arterial pressures (P<0.05) were observed after the losartan administration, without changes in mean arterial pressure or renal function.

CONCLUSION

Chronic AT-II type 1 receptor (AT1R) blockade may reduce liver fibrosis in patients with chronic hepatitis C.

Determinants of the renin-angiotensin-aldosterone system in cirrhosis with special emphasis on the central blood volume

OBJECTIVE

Several studies have shown activation of the renin-angiotensin-aldosterone system (RAAS) in cirrhosis. Although the activated RAAS may have several determinants, the system is often considered a surrogate marker of effective hypovolaemia. In this study we investigated the activity of the RAAS and its potential determinants with special focus on the central and arterial blood volume (CBV).

MATERIAL AND METHODS

Eighty-nine patients (Child class A/B/C: 19/41/29) and 32 controls were included in the study. All were given a haemodynamic examination with measurement of determinants of the RAAS, including the CBV. Circulating plasma renin concentrations were measured using an immunoradiometric assay.

RESULTS

Arterial renin concentrations were significantly higher in the patients than in the controls (p < 0.003). Plasma renin correlated significantly with several indicators of liver dysfunction and splanchnic and systemic haemodynamics (r = - 0.56-0.55), but only weakly with CBV (r = - 0.25, p < 0.02). In a multivariate regression analysis, plasma renin was determined by serum sodium, alkaline phosphatases and systolic blood pressure (p < 0.04 to p < 0.001).

CONCLUSIONS

CBV correlates weakly with circulating renin, and activation of the RAAS can therefore only partly be considered as an indicator of central hypovolaemia. Mechanisms other than central hypovolaemia relating to the liver disease and portal hypertension contribute significantly to the RAAS activation.

Increased hepatic resistance: a new target in the pharmacologic therapy of portal hypertension

Increased resistance to portal blood flow is the primary factor in the pathophysiology of portal hypertension, and is mainly determined by the morphologic changes occurring in chronic liver diseases. This is aggravated by an increased hepatic vascular tone, which results from an insufficient hepatic bioavailability of nitric oxide (NO) and an increased production of circulating and local vasoconstrictors (angiotensin, endothelin, cysteinyl-leukotrienes, and thromboxane, among others). This dynamic and reversible component provides the rationale for the use of therapies aimed at decreasing portal pressure by reducing the vascular tone. Among them, systemic and liver-selective NO donors, statins, and gene therapy with adenovirus encoding NO synthases have been used to increase NO availability with promising results. Other attempts have been the blockade of the effect of vasoconstrictors, using anti alpha-adrenergic agents and renin-angiotensin system blockers. Some of these pharmacologic approaches have already been incorporated into clinical practice while others are still under investigation.

Management of portal hypertension

Treatment of portal hypertension is evolving based on randomised controlled trials. In acute variceal bleeding, prophylactic antibiotics are mandatory, reducing mortality as well as preventing infections. Terlipressin or somatostatin combined with endoscopic ligation or sclerotherapy is the best strategy for control of bleeding but there is no added effect of vasoactive drugs on mortality. Non-selective beta-blockers are the first choice therapy for both secondary and primary prevention; if contraindications or intolerance to beta-blockers are present then band ligation should be used. Novel therapies target the increased intrahepatic resistance caused by microcirculatory intrahepatic deficiency of nitric oxide and contraction of activated intrahepatic stellate cells.

A1166C angiotensin II type 1 receptor gene polymorphism may predict hemodynamic response to losartan in patients with cirrhosis and portal hypertension

OBJECTIVE

Losartan, a dose of 25 mg/day, has been found to be effective in 50% of patients with portal hypertension without adverse effects. We evaluated the relationship between genetic polymorphisms of the renin-angiotensin system (A1166C angiotensin II type 1 receptor (AT1R), angiotensinogen T174M and M235T, and angiotensin-converting enzyme I/D) and the effects of losartan on portal and systemic hemodynamic in patients with cirrhosis and portal hypertension.

METHODS

We performed a longitudinal study that included 23 consecutive patients with cirrhosis and esophageal varices who received 25 mg/day of losartan during 12 wk. Hepatic venous pressure gradient (HVPG) and systemic hemodynamic were measured at baseline and after treatment. Genomic DNA was extracted from peripheral blood leukocytes; genetic polymorphisms of the renin-angiotensin system were investigated by polymerase chain reaction and restriction fragment length polymorphisms.

RESULTS

The homozygous patients for AT1R A allele showed higher pulmonary-wedged and free hepatic venous pressure on baseline. After treatment, they showed a higher decrease of HVPG (32.5%+/- 19.2) in comparison with patients with AC/CC genotype (2.4%+/-18.9), p < 0.01. Ten of 15 patients with AA genotype were responders, while only one of eight with AC/CC genotype (p < 0.002); genotype AA showed a positive predictive value of 66.6% and negative predictive value of 87.5%.

CONCLUSIONS

These results suggest that there is a relationship between the AT1R A1166C polymorphisms and the therapeutic response to losartan. The genetic testing may be used as a predictive factor of this response.

Role of the renin-angiotensin system in hepatic ischemia reperfusion injury in rats

It has been shown that the renin-angiotensin system (RAS) plays key roles in the development of fibrosis in numerous organs, including the liver. Other studies have suggested that the RAS also may play roles in diseases of chronic inflammation. However, whether the RAS also can mediate acute inflammation in liver is unclear. The purpose of this study therefore was to determine the effect of the RAS inhibitors captopril and losartan on acute liver damage and inflammation caused by hepatic ischemia and subsequent reperfusion. Accordingly, male rats were subjected to 1 hour of hepatic ischemia (70%) followed by reperfusion; animals were killed 3, 8, or 24 hours after reperfusion. The effect of captopril or losartan (100 or 5 mg/kg intragastrically, respectively) was compared with that of vehicle (saline). The expression of angiotensinogen in liver increased fivefold 3 hours after reperfusion. Indices of liver damage and inflammation (e.g., alanine aminotransferase levels, pathological features, tumor necrosis factor-alpha levels, and intercellular adhesion molecule-1 expression) all were significantly elevated in vehicle-treated animals after hepatic ischemia and subsequent reperfusion. Ischemia and reperfusion also caused an increase in the accumulation of protein adducts of 4-hydroxynonenal, an index of oxidative stress. Captopril or losartan treatment showed profound protective effects under these conditions, significantly blunting the increase in all these parameters caused by ischemia and reperfusion. In conclusion, RAS inhibitors prevent acute liver injury in a model of inflammation caused by ischemia and reperfusion. These data further suggest that the RAS may play a key role in mediating such responses in the liver and suggest a novel role for this system.

Nitric oxide and renal function in cirrhotic patients with ascites: from physiopathology to practice

Patients with cirrhosis and ascites show systemic and splanchnic arterial vasodilation, which causes a reduction in effective arterial blood volume and the activation of hormonal anti-natriuretic systems. Renal impairment is the most important predictor of hospital mortality in cirrhotic patients with SBP. In patients with SBP, the inflammatory response to the infection (TNF-alpha, IL-6) may be an important mechanism of renal dysfunction. Ascitic-fluid NO metabolites are related independently to the development of renal impairment. Treatment of SBP with intravenous albumin in addition to cefotaxime prevents renal impairment and reduces mortality in comparison with treatment with cefotaxime alone. As soon as ascites develops, liver transplantation should be considered in eligible patients, especially when local mean waiting times exceed life expectancy. Nitric oxide (NO), tumour necrosis factor alpha (TNF-alpha) and interleukin-6 (IL-6) have been implicated in the pathogenesis of circulatory alterations observed in cirrhotic patients with ascites. Kidney failure is one of the main factors associated with mortality in patients with end-stage liver disease developing complications, particularly severe infections and variceal haemorrhage. Renal impairment occurs in patients with the highest concentration of cytokines in plasma and ascitic fluid and is associated with marked activation of the renin-angiotensin system. In patients with spontaneous bacterial peritonitis (SBP), serum and ascitic fluid levels of NO metabolites (nitrites and nitrates) were higher than those of patients with sterile ascites, and renal impairment is considered to be caused by a decrease in effective arterial blood volume as a result of the infection. The administration of albumin prevents deterioration of renal function and reduces mortality in these patients. However, SBP and renal dysfunction are late complications in the course of liver cirrhosis. As soon as ascites develops, liver transplantation should be considered in eligible patients, especially when local mean waiting times exceed life expectancy. A better knowledge of metabolic disorders associated with the early stage of cirrhosis is essential for the development of optimal therapeutic strategies for the prophylaxis and treatment of portal hypertension and its complications.