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

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.

Statins, metformin, and RAS inhibitors did not reduce variceal bleeding risk and mortality in a large, real-life cohort of patients with cirrhosis

BACKGROUND

Previous experimental and clinical studies suggested a beneficial effect of statins, metformin, angiotensin-converting-enzyme inhibitors and angiotensin II receptor blockers (RASi) on portal hypertension. Still, their effects on hard cirrhosis-related clinical endpoints, such as variceal bleeding and bleeding-related mortality, remain to be investigated.

METHODS

Thus, we recorded the use of statins, metformin and RASi in a large cohort of cirrhotic patients undergoing endoscopic band ligation (EBL) for primary (PP, n = 440) and secondary bleeding prophylaxis (SP, n = 480) between 01/2000 and 05/2020. Variceal (re-) bleeding and survival rates were compared between patients with vs. without these co-medications.

RESULTS

A total of 920 cirrhotic patients with varices were included. At first EBL, median MELD was 13 and 515 (56%) patients showed ascites. Statins, metformin and RASi were used by 49 (5.3%), 74 (8%), and 91 (9.9%) patients, respectively. MELD and platelet counts were similar in patients with and without the co-medications of interest. Rates of first variceal bleeding and variceal rebleeding at 2 years were 5.2% and 11.7%, respectively. Neither of the co-medications were associated with decreased first bleeding rates (log-rank tests in PP: statins p = 0.813, metformin p = 0.862, RASi p = 0.919) nor rebleeding rates (log-rank tests in SP: statin p = 0.113, metformin p = 0.348, RASi p = 0.273). Similar mortality rates were documented in patients with and without co-medications for PP (log-rank tests: statins p = 0.630, metformin p = 0.591, RASi p = 0.064) and for SP (statins p = 0.720, metformin p = 0.584, RASi p = 0.118).

CONCLUSION

In clinical practice, variceal bleeding and mortality rates of cirrhotic patients were not reduced by co-medication with statins, metformin or RASi. Nevertheless, we recommend the use of these co-medications by indication, as they may still exert beneficial effects on non-bleeding complications in patients with liver cirrhosis.

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.

Candesartan cilexetil ameliorates NOSTRIN-NO dependent portal hypertension in cirrhosis and ACLF

In decompensated cirrhosis, the severity of portal hypertension (PHT) is associated with increased hepatic endothelial nitric oxide synthase (eNOS) trafficking inducer (Nostrin), but the mechanism remains unclear. AIM: To investigate: (1) Whether in cirrhosis-PHT models, ± superimposed inflammation to mimic acute-on-chronic liver failure (ACLF) modulates hepatic nitric oxide synthase trafficking inducer (NOSTRIN) expression, nitric oxide (NO) synthesis, and/or endothelial dysfunction (ED); and (2) Whether the "angiotensin II type 1 receptor blocker" candesartan cilexetil (CC) affects this pathway. CD-1 mice received intraperitoneal carbon tetrachloride injections (CCl4 15% v/v in corn oil, 0.5 mL/kg) twice weekly for 12 wk to induce cirrhosis. After 12 wk, mice were randomized to receive 2-wk oral administration of CC (8 mg/kg) ± LPS. At sacrifice, plasma (biochemical indicators, cytokines, and angiotensin II) and liver tissues (histopathology, Sirius-red stains, and molecular studies) were analysed. Moreover, Nostrin gene knockdown was tested in human umbilical vein endothelial cells (HUVECs). When compared to naïve animals, CCl4-treated animals showed markedly elevated hepatic Nostrin expression (P < 0.0001), while hepatic peNOS expression (measure of eNOS activity) was significantly reduced (P < 0.05). LPS challenge further increased Nostrin and reduced peNOS expression (P < 0.05 for both) in cirrhotic animals. Portal pressure and subsequent hepatic vascular resistance were also increased in all cirrhotic animals following LPS challenge. In CCl4 ± LPS-treated animals, CC treatment significantly reduced Nostrin (P < 0.05) and increased hepatic cGMP (P < 0.01). NOSIP, caveolin-1, NFκB, and iNOS protein expression were significantly increased in CCl4-treated animals (P < 0.05 for all). CC treatment non-significantly lowered NOSIP and caveolin-1 expression while iNOS and NFκB expression was significantly reduced in CCl4 + LPS-treated animals (P < 0.05 for both). Furthermore, Nostrin knockdown significantly improved peNOS expression and associated NO synthesis and reduced inflammation in HUVECs. This study is the first to indicate a potential mechanistic role for the Nostrin-eNOS-NO pathway in cirrhosis and ACLF development. Moreover, this pathway provides a potential therapeutic target given the ameliorative response to Candesartan treatment.

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.

Hepatocellular carcinoma chemoprevention by targeting the angiotensin-converting enzyme and EGFR transactivation

Hepatocellular carcinoma (HCC) is a leading cause of death among cirrhotic patients, for which chemopreventive strategies are lacking. Recently, we developed a simple human cell-based system modeling a clinical prognostic liver signature (PLS) predicting liver disease progression and HCC risk. In a previous study, we applied our cell-based system for drug discovery and identified captopril, an approved angiotensin converting enzyme (ACE) inhibitor, as a candidate compound for HCC chemoprevention. Here, we explored ACE as a therapeutic target for HCC chemoprevention. Captopril reduced liver fibrosis and effectively prevented liver disease progression toward HCC development in a diethylnitrosamine (DEN) rat cirrhosis model and a diet-based rat model for nonalcoholic steatohepatitis–induced (NASH-induced) hepatocarcinogenesis. RNA-Seq analysis of cirrhotic rat liver tissues uncovered that captopril suppressed the expression of pathways mediating fibrogenesis, inflammation, and carcinogenesis, including epidermal growth factor receptor (EGFR) signaling. Mechanistic data in liver disease models uncovered a cross-activation of the EGFR pathway by angiotensin. Corroborating the clinical translatability of the approach, captopril significantly reversed the HCC high-risk status of the PLS in liver tissues of patients with advanced fibrosis. Captopril effectively prevents fibrotic liver disease progression toward HCC development in preclinical models and is a generic and safe candidate drug for HCC chemoprevention.

Impact of Maternal Obesity on Liver Disease in the Offspring: A Comprehensive Transcriptomic Analysis and Confirmation of Results in a Murine Model

The global obesity epidemic particularly affects women of reproductive age. Offspring of obese mothers suffer from an increased risk of liver disease but the molecular mechanisms involved remain unknown. We performed an integrative genomic analysis of datasets that investigated the impact of maternal obesity on the hepatic gene expression profile of the offspring in mice. Furthermore, we developed a murine model of maternal obesity and studied the development of liver disease and the gene expression profile of the top dysregulated genes by quantitative real-time polymerase chain reaction (qPCR). Our data are available for interactive exploration on our companion webpage. We identified five publicly available datasets relevant to our research question. Pathways involved in metabolism, the innate immune system, the clotting cascade, and the cell cycle were consistently dysregulated in the offspring of obese mothers. Concerning genes involved in the development of liver disease, Egfr, Vegfb, Wnt2,Pparg and six other genes were dysregulated in multiple independent datasets. In our own model, we observed a higher tendency towards the development of non-alcoholic liver disease (60 vs. 20%) and higher levels of alanine aminotransferase (41.0 vs. 12.5 IU/l, p = 0.008) in female offspring of obese mothers. Male offspring presented higher levels of liver fibrosis (2.4 vs. 0.6% relative surface area, p = 0.045). In a qPCR gene expression analysis of our own samples, we found Fgf21, Pparg, Ppard, and Casp6 to be dysregulated by maternal obesity. Maternal obesity represents a looming threat to the liver health of future generations. Our comprehensive transcriptomic analysis will help to better understand the mechanisms of the development of liver disease in the offspring of obese mothers and can give rise to further explorations.

Test-Retest Reliability and Consistency of HVPG and Impact on Trial Design: A Study in 289 Patients from 20 Randomized Controlled Trials

BACKGROUND AND AIMS

Portal hypertension (PH) is a major driver for cirrhosis complications. Portal pressure is estimated in practice by the HVPG. The assessment of HVPG changes has been used for drug development in PH. This study aimed at quantifying the test-retest reliability and consistency of HVPG in the specific context of randomized controlled trials (RCTs) for the treatment of PH in cirrhosis and its impact on power calculations for trial design.

APPROACH AND RESULTS

We conducted a search of published RCTs in patients with cirrhosis reporting individual patient-level data of HVPG at baseline and after an intervention, which included a placebo or an untreated control arm. Baseline and follow-up HVPGs in the control groups were extracted after digitizing the plots. We assessed reliability and consistency and the potential impact of study characteristics. We retrieved a total of 289 before and after HVPG measurements in the placebo/untreated groups from 20 RCTs. The time span between the two HVPG measurements ranged between 20 minutes and 730 days. Pre-/post-HVPG variability was lower in studies including only compensated patients; therefore, modeled sample size calculations for trials in compensated cirrhosis were lower than for decompensated cirrhosis. A higher proportion of alcohol-associated cirrhosis and unicentric trials was associated with lower differences between baseline and follow-up measurements. The smallest detectable difference in an individual was 26% and 30% in compensated and decompensated patients, respectively.

CONCLUSIONS

The test-retest reliability of HVPG is overall excellent. Within-individual variance was higher in studies including higher proportions of decompensated patients. These findings should be taken into account when performing power analysis for trials based on the effects on HVPG or when considering HVPG as a tool to guide therapy of PH.

Congenital hepatic fibrosis: case report and review of literature

Congenital hepatic fibrosis (CHF) is a rare autosomal recessive disease derived from biliary dysgenesis secondary to ductal plate malformation; it often coexists with Caroli's disease, von Meyenburg complexes, autosomal dominant polycystic kidney disease (ADPKD), and autosomal recessive polycystic kidney disease (ARPKD). Although CHF was first named and described in detail by Kerr et al. in 1961. Its pathogenesis still remains unclear. The exact incidence and prevalence are not known, and only a few hundred patients with CHF have been reported in the literature to date. However, with the development of noninvasive diagnostic techniques such as ultrasound, computed tomography (CT), and magnetic resonance imaging (MRI), CHF may now be more frequently detected. Anatomopathological examination of liver biopsy is the gold standard in diagnosis of CHF. Patients with CHF exhibit variable clinical presentations, ranging from no symptoms to severe symptoms such as acute hepatic decompensation and even cirrhosis. The most common presentations in these patients are splenomegaly, esophageal varices, and gastrointestinal bleeding due to portal hypertension. In addition, in younger children, CHF often is accompanied by renal cysts or increased renal echogenicity. Great variability exists among the signs and symptoms of the disease from early childhood to the 5th or 6th decade of life, and in most patients the disorder is diagnosed during adolescence or young adulthood. Here, we present two cases of congenital hepatic fibrosis in 2-years-old girl and 12-year-old male who had been referred for evaluation of an abdominal distension with persistent hyper-transaminasemia and cholestasis, the diagnostic was made according to the results of medical imaging (CT or MRI), a liver biopsy, and genetic testing.

Update on New Aspects of the Renin-Angiotensin System in Hepatic Fibrosis and Portal Hypertension: Implications for Novel Therapeutic Options

There is considerable experimental evidence that the renin angiotensin system (RAS) plays a central role in both hepatic fibrogenesis and portal hypertension. Angiotensin converting enzyme (ACE), a key enzyme of the classical RAS, converts angiotensin I (Ang I) to angiotensin II (Ang II), which acts via the Ang II type 1 receptor (AT1R) to stimulate hepatic fibrosis and increase intrahepatic vascular tone and portal pressure. Inhibitors of the classical RAS, drugs which are widely used in clinical practice in patients with hypertension, have been shown to inhibit liver fibrosis in animal models but their efficacy in human liver disease is yet to be tested in adequately powered clinical trials. Small trials in cirrhotic patients have demonstrated that these drugs may lower portal pressure but produce off-target complications such as systemic hypotension and renal failure. More recently, the alternate RAS, comprising its key enzyme, ACE2, the effector peptide angiotensin-(1–7) (Ang-(1–7)) which mediates its effects via the putative receptor Mas (MasR), has also been implicated in the pathogenesis of liver fibrosis and portal hypertension. This system is activated in both preclinical animal models and human chronic liver disease and it is now well established that the alternate RAS counter-regulates many of the deleterious effects of the ACE-dependent classical RAS. Work from our laboratory has demonstrated that liver-specific ACE2 overexpression reduces hepatic fibrosis and liver perfusion pressure without producing off-target effects. In addition, recent studies suggest that the blockers of the receptors of alternate RAS, such as the MasR and Mas related G protein-coupled receptor type-D (MrgD), increase splanchnic vascular resistance in cirrhotic animals, and thus drugs targeting the alternate RAS may be useful in the treatment of portal hypertension. This review outlines the role of the RAS in liver fibrosis and portal hypertension with a special emphasis on the possible new therapeutic approaches targeting the ACE2-driven alternate RAS.

ACE2: from protection of liver disease to propagation of COVID-19

Twenty years ago, the discovery of angiotensin-converting enzyme 2 (ACE2) was an important breakthrough dramatically enhancing our understanding of the renin-angiotensin system (RAS). The classical RAS is driven by its key enzyme ACE and is pivotal in the regulation of blood pressure and fluid homeostasis. More recently, it has been recognised that the protective RAS regulated by ACE2 counterbalances many of the deleterious effects of the classical RAS. Studies in murine models demonstrated that manipulating the protective RAS can dramatically alter many diseases including liver disease. Liver-specific overexpression of ACE2 in mice with liver fibrosis has proved to be highly effective in antagonising liver injury and fibrosis progression. Importantly, despite its highly protective role in disease pathogenesis, ACE2 is hijacked by SARS-CoV-2 as a cellular receptor to gain entry to alveolar epithelial cells, causing COVID-19, a severe respiratory disease in humans. COVID-19 is frequently life-threatening especially in elderly or people with other medical conditions. As an unprecedented number of COVID-19 patients have been affected globally, there is an urgent need to discover novel therapeutics targeting the interaction between the SARS-CoV-2 spike protein and ACE2. Understanding the role of ACE2 in physiology, pathobiology and as a cellular receptor for SARS-CoV-2 infection provides insight into potential new therapeutic strategies aiming to prevent SARS-CoV-2 infection related tissue injury. This review outlines the role of the RAS with a strong focus on ACE2-driven protective RAS in liver disease and provides therapeutic approaches to develop strategies to prevent SARS-CoV-2 infection in humans.

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.

The skeletal renin-angiotensin system: A potential therapeutic target for the treatment of osteoarticular diseases

The classical renin-angiotensin system (RAS) is known to be a key regulator of blood pressure as well as fluid and electrolyte homeostasis. Additionally, it is now evident that components of the RAS are produced and act locally in many tissues, including liver, kidney, heart, lung, eye, bone, reproductive organ, adipose, and adrenal tissue, and these components are collectively known as tissue RAS. Recently, several studies have shown that local bone RAS is directly involved in bone metabolism, and activation of skeletal RAS plays an important role in bone diseases, such as osteoporosis, arthritis, and deterioration as well as in fracture healing. Based on the identification of RAS components in bone, we examined a new therapeutic approach to attenuate bone diseases through RAS inhibitors: renin inhibitor, angiotensin-converting enzyme inhibitors, and angiotensin II receptor blockers. In this paper, we provide a systematic review of the skeletal RAS in the pathophysiology of bone diseases and the beneficial effect of RAS inhibitors on bone tissue.

Portal Hypertension and Related Complications: Diagnosis and Management

Portal hypertension is a major complication of cirrhosis, and its consequences, including ascites, esophageal varices, hepatic encephalopathy, and hepatorenal syndrome, lead to substantial morbidity and mortality. The past several decades have seen major improvements in the clinical management of complications of portal hypertension, resulting in substantial gains in patient outcomes. However, important challenges remain. This review focuses on the pathophysiology and diagnosis of portal hypertension and discusses general approaches in the management of patients with ascites as a result of portal hypertension.

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.

CONGENITAL HEPATIC FIBROSIS AND OBLITERATIVE PORTAL VENOPATHY WITHOUT PORTAL HYPERTENSION - A REVIEW OF LITERATURE BASED ON AN ASYMPTOMATIC CASE

The disease and the case reported here are relevant especially because of their varied clinical presentation, possibility of being associated with other disorders affecting several organs and possible differential diagnoses. Congenital Hepatic Fibrosis is an autosomal recessive disease due to mutation in the PKHD1 gene, which encodes the fibrocystin/polyductine protein. It is a cholangiopathy, characterized by varying degrees of periportal fibrosis and irregular proliferation of bile ducts. Affected patients are typically diagnosed in childhood, but in some cases the disease may remain asymptomatic for many years. The exact prevalence and incidence of the disease are not known, but it is consider a rare disease, with a few hundred cases described worldwide. It can affect all ethnic groups and occur associated with various hereditary and non-hereditary disorders. The clinical presentation is quite variable, with melena and hematemesis being initial symptoms in 30%-70% of the cases. More rarely, they may present episodes of cholangitis. The disease has been classified into four types: portal hypertension, cholestasis / cholangitis, mixed and latent. Diagnosis begins with imaging tests, but the definition is made by the histopathological sample. So far, there is no specific therapy that can stop or reverse the pathological process. Currently, the therapeutic strategy is to treat the complications of the disease.

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.

Periostin cross‑reacts with the renin‑angiotensin system during liver fibrosis development

Periostin is a 90‑kDa extracellular matrix protein, which is secreted primarily from fibroblasts and is expressed in the lungs, kidneys and heart valves. Angiotensin II (AT‑II) serves pivotal roles in the pathogenesis of several diseases with accompanying fibrosis, including chronic liver diseases. AT‑II induces periostin expression by regulating transforming growth factor‑β1 (TGF‑β1)/Smad signaling during cardiac fibrosis. The aim of the present study was to investigate the interaction between AT‑II and periostin during liver fibrosis development. Fischer 344 rats were fed a choline‑deficient L‑amino‑acid (CDAA)‑defined diet for 12 weeks to simulate the development of steatohepatitis with liver fibrosis. Losartan, an AT‑II type I receptor blocker, was administered to inhibit the effect of AT‑II. The therapeutic effect of losartan on hepatic fibrosis development and on periostin expression was then evaluated. Several in vitro experiments were performed to examine the mechanisms underlying the interaction between AT‑II and periostin in activated hepatic stellate cells (Ac‑HSCs). Treatment with losartan suppressed the development of liver fibrosis induced by the CDAA diet, and reduced hepatic periostin expression. In addition, losartan treatment suppressed hepatic Ac‑HSC expansion and hepatic TGF‑β1 expression. In vitro analysis using LX2 HSC cells indicated that AT‑II can augment TGF‑β1 and collagen type I α1 mRNA expression via periostin expression, suggesting that the interaction between AT‑II and periostin may serve a role in liver fibrosis development. In conclusion, blockade of AT‑II‑induced periostin may suppress the progression of liver fibrosis development.

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.

RASAL1 is a potent regulator of hepatic stellate cell activity and liver fibrosis

Liver fibrosis, leading to cirrhosis and liver failure, can occur after chronic liver injury. The transition of hepatic stellate cells (HSCs) from quiescent cells into proliferative and fibrogenic cells is a central event in liver fibrosis. Here, we show that RAS protein activator like-1 (RASAL1), a RAS-GTPase-activating protein, which switches off RAS activity, is significantly decreased during HSC activation, and that HSC activation can be antagonized by forced expression of the RASAL1 protein. We demonstrate that RASAL1 suppresses HSC proliferation by regulating the Ras-MAPK pathway, and that RASAL1 suppresses HSC fibrogenic activity by regulating the PKA-LKB1-AMPK-SRF pathway by interacting with angiotensin II receptor, type 1. We also show that RASAL1-deficient mice are more susceptible to liver fibrosis. These data demonstrate that deregulated RASAL1 expression levels and the affected downstream intracellular signaling are central mediators of perpetuated HSC activation and fibrogenesis in the liver.

Molecular interplays in hepatic stellate cells: apoptosis, senescence, and phenotype reversion as cellular connections that modulate liver fibrosis

Liver fibrosis is a pathophysiological process correlated with intense repair and cicatrization mechanisms in injured liver, and over the past few years, the characterization of the fine-tuning of molecular interconnections that support the development of liver fibrosis has been investigated. In this cellular process, the hepatic stellate cells (HSCs) support the organ fibrogenesis. The HSCs are found in two distinct morpho-physiological states: quiescent and activated. In normal liver, most HSCs are found in quiescent state, presenting a considerable amount of lipid droplets in the cytoplasm, while in injured liver, the activated phenotype of HSCs is a myofibroblast, that secrete extracellular matrix elements and contribute to the establishment of the fibrotic process. Studies on the molecular mechanisms by which HSCs try to restore their quiescent state have been performed; however, no effective treatment to reverse fibrosis has been so far prescribed. Therefore, the elucidation of the cellular and molecular mechanisms of apoptosis, senescence, and the cell reversion phenotype process from activate to quiescent state will certainly contribute to the development of effective therapies to treat hepatic fibrosis. In this context, this review aimed to address central elements of apoptosis, senescence, and reversal of HSC phenotype in the control of hepatic fibrogenesis, as a guide to future development of therapeutic strategies.

MicroRNA-21 Mediates Angiotensin II-Induced Liver Fibrosis by Activating NLRP3 Inflammasome/IL-1β Axis via Targeting Smad7 and Spry1

AIMS

Angiotensin II (AngII), a vasoconstrictive peptide of the renin-angiotensin system (RAS), promotes hepatic fibrogenesis and induces microRNA-21(mir-21) expression. Angiotensin-(1-7) [Ang-(1-7)] is a peptide of the RAS, which attenuates liver fibrosis. Recently, it was reported that the NOD-like receptor family, pyrin domain containing 3 (NLRP3) inflammasome participated in liver fibrosis. However, it remains unclear how mir-21 mediates AngII-induced NLRP3 inflammasome activation. We investigate the role of AngII-induced mir-21 in the regulation of NLRP3 inflammasome/IL-1β axis in liver fibrosis.

RESULTS

In vivo, circulating mir-21 was upregulated in patients with liver fibrosis and was positively correlated with liver fibrosis and oxidation. Treatment with Ang-(1-7) inhibited mir-21, NLRP3 inflammasome, and liver fibrosis after bile duct ligation (BDL) or AngII infusion. Inhibition of mir-21 suppressed the Smad7/Smad2/3/NOX4, Spry1/ERK/NF-κB pathway, NLRP3 inflammasome, and liver fibrosis induced by AngII infusion. In vitro, AngII upregulated mir-21 expression via targeting Smad7 and Spry1 in primary hepatic stellate cells (HSCs). In contrast, Ang-(1-7) suppressed mir-21 expression and oxidation induced by AngII. Overexpression of mir-21 promoted oxidation, and collagen production enhanced the effect of AngII on NLRP3 inflammasome activation via the Spry1/ERK/NF-κB, Smad7/Smad2/3/NOX4 pathways. However, downregulation of mir-21 exerted the opposite effects. Innovation and Conclusions: Mir-21 mediates AngII-activated NLRP3 inflammasome and resultant HSC activation via targeting Spry1 and Smad7. Ang-(1-7) protected against BDL or AngII infusion-induced hepatic fibrosis and inhibited mir-21 expression. Antioxid. Redox Signal. 27, 1-20.

Novel treatment options for portal hypertension

Portal hypertension is most frequently associated with cirrhosis and is a major driver for associated complications, such as variceal bleeding, ascites or hepatic encephalopathy. As such, clinically significant portal hypertension forms the prelude to decompensation and impacts significantly on the prognosis of patients with liver cirrhosis. At present, non-selective β-blockers, vasopressin analogues and somatostatin analogues are the mainstay of treatment but these strategies are far from satisfactory and only target splanchnic hyperemia. In contrast, safe and reliable strategies to reduce the increased intrahepatic resistance in cirrhotic patients still represent a pending issue. In recent years, several preclinical and clinical trials have focused on this latter component and other therapeutic avenues. In this review, we highlight novel data in this context and address potentially interesting therapeutic options for the future.

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.

Role of renin-angiotensin system in liver diseases: an outline on the potential therapeutic points of intervention

The current review aimed to outline the functions of the renin angiotensin system (RAS) in the context of the oxidative stress-associated liver disease. Areas covered: Angiotensin II (Ang II) as the major effector peptide of the RAS is a pro-oxidant and fibrogenic cytokine. Mechanistically, NADPH oxidase (NOX) is a multicomponent enzyme complex that is able to generate reactive oxygen species (ROS) as a downstream signaling pathway of Ang II which is expressed in liver. Ang II has a detrimental role in the pathogenesis of chronic liver disease through possessing pro-oxidant, fibrogenic, and pro-inflammatory impact in the liver. The alternative axis (ACE2/Ang(1-7)/mas) of the RAS serves as an anti-inflammatory, antioxidant and anti-fibrotic component of the RAS. Expert commentary: In summary, the use of alternative axis inhibitors accompanying with ACE2/ Ang(1-7)/mas axis activation is a promising new strategy serving as a novel therapeutic option to prevent and treat chronic liver diseases.

Therapeutic effect of renin angiotensin system inhibitors on liver fibrosis

BACKGROUND AND OBJECTIVE

Currently, there is no effective therapy available for liver fibrosis. This study aims to evaluate the efficacy of renin angiotensin system inhibitors on liver fibrosis.

METHOD

Full-text randomized controlled trials in patients with liver fibrosis were identified and included in the meta-analysis. The primary outcome measure was the histological fibrosis score of the liver. Secondary outcome measures included fibrosis area of the liver, serological levels of fibrosis markers, adverse events, and withdrawals.

RESULTS

From 6973 non-duplicated entries by systematic search, four randomized controlled trials with 210 patients were identified. The renin angiotensin system inhibitors therapy resulted in a marginally significant reduction in liver fibrosis score (MD = -0.30; 95% CI: -0.62-0.02, p = 0.05) and a significant reduction in liver fibrosis area (MD = -2.36%; 95% CI: -4.22%--0.50%, p = 0.01) as compared with control. The therapy was well tolerated and there was no significant difference in withdrawals between treatment and control groups (RD = 0.00; 95% CI: -0.06-0.06, p = 0.97).

CONCLUSIONS

Renin angiotensin system inhibitor therapy results in a reduction in liver fibrosis score and liver fibrosis area in patients with hepatic fibrosis with good safety profile. However, randomized controlled trials of high-quality will clarify the effectiveness of renin angiotensin system inhibitors on liver fibrosis.

Endothelial dysfunction in cirrhosis: Role of inflammation and oxidative stress

This review describes the recent developments in the pathobiology of endothelial dysfunction (ED) in the context of cirrhosis with portal hypertension and defines novel strategies and potential targets for therapy. ED has prognostic implications by predicting unfavourable early hepatic events and mortality in patients with portal hypertension and advanced liver diseases. ED characterised by an impaired bioactivity of nitric oxide (NO) within the hepatic circulation and is mainly due to decreased bioavailability of NO and accelerated degradation of NO with reactive oxygen species. Furthermore, elevated inflammatory markers also inhibit NO synthesis and causes ED in cirrhotic liver. Therefore, improvement of NO availability in the hepatic circulation can be beneficial for the improvement of endothelial dysfunction and associated portal hypertension in patients with cirrhosis. Furthermore, therapeutic agents that are identified in increasing NO bioavailability through improvement of hepatic endothelial nitric oxide synthase (eNOS) activity and reduction in hepatic asymmetric dimethylarginine, an endogenous modulator of eNOS and a key mediator of elevated intrahepatic vascular tone in cirrhosis would be interesting therapeutic approaches in patients with endothelial dysfunction and portal hypertension in advanced liver diseases.

Dipeptidyl peptidase-4 inhibitor attenuates hepatic fibrosis via suppression of activated hepatic stellate cell in rats

BACKGROUND

Dipeptidyl peptidase-4 inhibitor (DPP4-I) is clinically used as a new oral antidiabetic agent. Although DPP4 is reportedly associated with the progression of chronic liver diseases, the effect of DPP4-I on liver fibrosis development is still obscure. This study was designed to elucidate the effect of DPP4-I on liver fibrosis development in conjunction with the activated hepatic stellate cells (Ac-HSCs).

METHODS

The antifibrotic effect of DPP4-I was assessed in vivo and in vitro using porcine serum-induced experimental liver fibrosis model. DPP4-I, sitagliptin, at a clinically comparable low dose was administered by gavage daily.

RESULTS

DPP4-I significantly attenuated liver fibrosis development along with the suppression of hepatic transforming growth factor (TGF)-β1, total collagen, and tissue inhibitor of metalloproteinases-1 in a dose-dependent manner. These suppressive effects occurred almost concurrently with the attenuation of HSCs activation. Our in vitro studies showed that DPP4-I inhibited platelet-derived growth factor-BB-mediated proliferation of the Ac-HSCs as well as upregulation of TGF-β1 and α1(I)-procollagen at magnitudes similar to those of the in vivo studies. The inhibitory effects of DPP4-I against HSCs proliferation and fibrogenic gene expression are mediated through the inhibition of the phosphorylation of ERK1/2, p38 and Smad2/3, respectively.

CONCLUSIONS

DPP4-I markedly inhibits liver fibrosis development in rats via suppression of HSCs proliferation and collagen synthesis. These suppressive effects are associated with dephosphorylation of ERK1/2, p38 and Smad2/3 in the HSCs. Since DPP4-I is widely used in clinical practice, this drug may represent a potential new therapeutic strategy against liver fibrosis in the near future.

Pre-primary and Primary Prophylaxis of Variceal Hemorrhage

Variceal hemorrhage is a life-threatening complication of portal hypertension. Thus, prevention of variceal formation (pre-primary prophylaxis) or at least prevention of variceal bleeding are important goals to improve life quality and—if possible—survival of patients with liver cirrhosis. Interruption of the underlying cause of liver disease is the most successful approach, which, however, often fails. For this situation interruption or modulation of different pathophysiological mechanisms leading to fibrosis, hyperdynamic circulation and portal hypertension have been shown effective in animal models. But few could be translated to humans. By contrast, different steps to prevent first bleeding from varices have proven successful in many clinical trials. These applied mainly drugs to lower portal pressure, such as nonselective β-blockers, or endoscopic obliteration of varices, while prophylactic shunt procedures are not advised.

Alteration of the ERK5 pathway by hydroxysafflor yellow A blocks expression of MEF2C in activated hepatic stellate cells in vitro: Potential treatment for hepatic fibrogenesis

Abstract Context: Hepatic fibrosis ultimately leads to cirrhosis if not treated effectively. Hepatic stellate cells (HSC) are a main mediator of hepatic fibrosis through the accumulation of extracellular matrix proteins. Suppression activation of passaged HSC has been proposed as therapeutic strategies for the treatment and prevention of hepatic fibrosis. Objective: To evaluate the effect of hydroxysafflor yellow A (HSYA), an active chemical compound derived from the flowers of Carthamus tinctorius L. (Compositae), on HSC inhibition, and to begin elucidating underlying mechanisms. Materials and methods: Primary HSCs were isolated from rats by in situ pronase/collagenase perfusion. Culture-activated HSCs were treated with or without HSYA at 30 μM in the presence or absence of PD98059 for 48 h, and then cell proliferation was measured by MTS assays. Messenger RNA (mRNA) expression was quantified by polymerase chain reaction, and protein was quantified by Western blots or enzyme-linked immunosorbent assays. Results: HSYA significantly inhibits culture-activated HSC proliferation in a dose-dependent and time-dependent manner with an IC50 value of 112.79 μM. HSYA (30 μM) induce the suppression of HSC activation, as indicated by decreases in contents of type I alpha collagen in HSC-cultured media and expression of α-smooth muscle actin protein in culture-activated HSC by 55 and 71%, respectively. HSYA (30 μM) also caused significant decreases in mRNA expression of type III alpha collagen in HSC by 28%. HSYA (30 μM) suppresses myocyte enhancer factor 2 C (MEF2C) expression both at its mRNA and protein levels by 60 and 61%, respectively. Further study demonstrated that HSYA (30 μM) caused significant decreases in p-ERK5 by 49%. Blocking extracellular signal-regulated protein kinase 5 (ERK5) activity by XMD 8--92, an ERK5 inhibitor, markedly abrogated the inhibitive effects of HSYA on HSC activation, and blocked the HSYA-mediated MEF2C down-regulation. Conclusions: HSYA suppress HSC activation by ERK5-mediated MEF2C down-regulation and makes it a potential candidate for prevention and treatment of hepatic fibrogenesis.

VSL#3 ® probiotic therapy does not reduce portal pressures in patients with decompensated cirrhosis

BACKGROUND & AIMS

In patients with decompensated cirrhosis, bacterial translocation can contribute to splanchnic vasodilatation, decreased effective circulating volume, and portal hypertension. The primary objective of this randomized, double blind placebo controlled trial was to evaluate the effect of the probiotic VSL#3(®) on the hepatic venous pressure gradient (HVPG).

METHODS

Seventeen patients with decompensated cirrhosis and an HVPG of ≥ 10 mmHg were randomized to receive 2 months of VSL#3(®) or an identical placebo. HVPG, endotoxin, interleukin (IL)-6, IL-8, IL-10, renin, aldosterone, nitric oxide and stool microbiota were measured at baseline and study end.

RESULTS

Two of the 17 patients were taken off the trial before completion (one for alcohol abuse and the second for SBP - both in placebo arm). Data were analysed on the remaining 15 patients. The median model for end-stage liver disease score was 12, and 80% of patients had Child Pugh B disease. The treatment arm had a greater decrease in HVPG from baseline to study end than the placebo arm (median change from baseline -11.6% vs +2.8%), although this reduction was not statistically significant in either group. There was a significant reduction in the plasma aldosterone level in the VSL#3(®) group, but no significant changes in the other measured parameters, including the stool microflora analysis.

CONCLUSIONS

Within the limitations of our sample size, VSL#3(®) therapy does not appear to have a significant impact on portal pressure reduction in patients with decompensated cirrhosis.

Hepatic fibrosis and the renin-angiotensin system

The renin-angiotensin system (RAS) is involved in hepatic fibrosis. To date there is no known effective treatment for hepatic fibrosis. Modulation of the RAS with angiotensin converting enzyme inhibitors and angiotensin receptor blockers may be a promising therapeutic option for the treatment of hepatic fibrosis. This review provides an update about the role of RAS in hepatic fibrosis, and treatment of hepatic fibrosis in the light of different studies in animals and humans is also updated. RAS induces key steps involved in hepatic fibrosis, such as activation of hepatic stellate cells and expression of transforming growth factor β1. Treatment with angiotensin-converting enzyme inhibitors, and angiotensin receptor blockers attenuate fibrosis progression in both animal and human studies. Further, controlled studies are required to evaluate the role of RAS inhibitors and angiotensin-converting enzyme 2 in patients with chronic liver diseases in whom the causative agent cannot be removed.

Beneficial effects of candesartan, an angiotensin-blocking agent, on compensated alcoholic liver fibrosis - a randomized open-label controlled study

BACKGROUND

Recent studies have shown that the renin-angiotensin system is implicated in hepatic fibrogenesis in vitro and in vivo. However, no study was done in humans with alcoholic liver disease.

AIM

To investigate the antifibrotic effect of angiotensin II type 1 receptor (AT1-R) blocking agents (ARB) in patients with alcoholic liver disease.

METHODS

The primary outcome was improvement in patients' histological features. Eighty-five patients with compensated alcoholic liver fibrosis (≥ F2) which was confirmed by baseline liver biopsy were randomized (intention-to-treat (ITT)) to receive either ARB, candesartan (8 mg/day) with ursodeoxycholic acid (UDCA) (600 mg/day) (n = 42) or UDCA alone (n = 43) as control for 6 months and follow-up liver biopsies were conducted.

RESULTS

According to the Laennec fibrosis system, candesartan showed significantly higher rates of histological improvements (ITT, 33.3% vs. 11.6%, P = 0.020). In addition, the fibrosis score was significantly reduced from 3.4 ± 1.4 to 3.1 ± 1.5 (P = 0.005) in the candesartan group. Candesartan also reduced the area of fibrosis and α-smooth muscle actin positive from 11.3 ± 6.0 to 8.3 ± 4.7 and 28.7 ± 10.5 to 23.9 ± 10.3 (%), and the hydroxyproline levels (μg/g liver tissue) from 7.8 ± 2.4 to 6.3 ± 1.7 respectively (P < 0.05). In addition, the relative expression of transforming growth factor-β1(TGF-β1), collagen-1, AT1-R, tissue inhibitor of metalloproteinase 1 (TIMP-1), metalloproteinases2 (MMP2), Rac1 and p22phox by real-time RT-PCR decreased in the candesartan group (P < 0.05). Mean arterial blood pressure in the candesartan group decreased mildly but significantly (P < 0.001). No significant complications and side effects were observed during the present study.

CONCLUSIONS

Administration of ARB in compensated alcoholic liver disease induces improvement of fibrosis in histological and quantitative measurements.

Update on new aspects of the renin-angiotensin system in liver disease: clinical implications and new therapeutic options

The RAS (renin-angiotensin system) is now recognized as an important regulator of liver fibrosis and portal pressure. Liver injury stimulates the hepatic expression of components of the RAS, such as ACE (angiotensin-converting enzyme) and the AT(1) receptor [AngII (angiotensin II) type 1 receptor], which play an active role in promoting inflammation and deposition of extracellular matrix. In addition, the more recently recognized structural homologue of ACE, ACE2, is also up-regulated. ACE2 catalyses the conversion of AngII into Ang-(1-7) [angiotensin-(1-7)], and there is accumulating evidence that this 'alternative axis' of the RAS has anti-fibrotic, vasodilatory and anti-proliferative effects, thus counterbalancing the effects of AngII in the liver. The RAS is also emerging as an important contributor to the pathophysiology of portal hypertension in cirrhosis. Although the intrahepatic circulation in cirrhosis is hypercontractile in response to AngII, resulting in increased hepatic resistance, the splanchnic vasculature is hyporesponsive, promoting the development of the hyperdynamic circulation that characterizes portal hypertension. Both liver fibrosis and portal hypertension represent important therapeutic challenges for the clinician, and there is accumulating evidence that RAS blockade may be beneficial in these circumstances. The present review outlines new aspects of the RAS and explores its role in the pathogenesis and treatment of liver fibrosis and portal hypertension.

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.

Elevated levels of circulating angiotensin converting enzyme in patients with hepatoportal sclerosis

BACKGROUND AND AIMS

Hepatoportal sclerosis (HPS) is a clinicopathologic condition that is clinically characterized by portal hypertension (varices and portosystemic collateral vessels), splenomegaly and pancytopenia, in the absence of cirrhosis. Although the etiology is obscure, a number of theories such as immunologic and vascular endothelial cellular abnormalities have been put forward to explain the underlying pathophysiology. Angiotensin-converting enzyme (ACE), an important molecule of the renin-angiotensin system (RAS), is also known as a regulatory molecule in systemic and portal circulation in distinct disorders. The aim of the present study was to investigate the possible role of the ACE in the context of RAS in HPS pathogenesis.

MATERIALS AND METHODS

The study was conducted on 30 HPS patients (16 men, 14 women; median age 36 years, range 18-63) and 20 healthy controls. The clinical features of HPS patients including demographics, laboratory, and ultrasonography findings were summarized. Serum ACE levels were measured by using commercially available kits.

RESULTS

Serum median ACE levels were 36 (8-174) U/l and 16 (8-43) U/l for the HPS patients and controls, respectively. Serum ACE levels were significantly higher in patients with HPS compared to the control group (P < 0.05).

CONCLUSION

ACE in the context of RAS may be associated with pathological endothelial occlusive events in the microenvironment of the portal circulation in HPS. Revealing the interactions between circulating and local RAS within the hepatic microenvironment would enlighten the biologic basis and clinical management of liver diseases.

The effects of angiotensin blocking agents on the progression of liver fibrosis in the HALT-C Trial cohort

BACKGROUND

Therapies that can slow the progression of liver fibrosis in chronic liver disease are needed. Evidence suggests that the renin-angiotensin system (RAS) contributes to inflammation and fibrosis in chronic liver disease. Both animal and limited human studies have shown that RAS inhibition with angiotensin-converting enzyme inhibitors (ACEi) and angiotensin receptor-1 [AT-1] blockers (ARBs) has antifibrogenic properties.

AIMS

In this study, we evaluated the effects of continuous ACEi/ARB use for 3.5 years on histological liver fibrosis progression in the HALT-C Trial cohort.

METHODS

In the HALT-C Trial, subjects with chronic hepatitis C and advanced hepatic fibrosis (Ishak stage ≥3) underwent serial liver biopsies at baseline, 1.5 years, and 3.5 years after randomization. The primary outcome was a ≥2-point increase in Ishak fibrosis score in at least one of the two serial biopsies. Sixty-six subjects were continuously taking ACEi/ARBs over the observation period, 126 were taking other antihypertensive medications, and 343 subjects took no antihypertensive medications.

RESULTS

The three groups were similar in baseline fibrosis scores, and the two groups being treated with antihypertensives were taking a similar number of antihypertensive medications. Fibrosis progression occurred in 33.3% of the ACEi/ARB group, 32.5% of the other antihypertensive medications group, and in 25.7% of subjects taking no antihypertensive medications. No significant associations between ≥2-point increases in fibrosis scores and continuous ACEi/ARB use were apparent at either 1.5 or 3.5 years in diabetes-adjusted and unadjusted odds ratios.

CONCLUSIONS

ACEi/ARB therapy did not retard the progression of hepatic fibrosis.

Advances in understanding the role of the UII/UT system in the pathogenesis of portal hypertension

Urotensin II (UII), a vasoactive peptide with structural similarity to somatostatin, is the most potent vasoconstrictor known in systemic resistance vessels and has multiple biological effects related to a variety of human diseases. Numerous studies have found that UII and its receptor (UT) play an important role in the pathogenesis of portal hypertension. This paper reviews the recent advances in understanding the role of the UII/UT system in the pathogenesis of portal hypertension.

Cell death and fibrogenesis

Fibrosis is a common feature of chronic liver injury and is initiated by cell death inside the liver. Hepatocyte death results in apoptotic bodies and other cellular debris, which are phagocytosed by hepatic stellate cells (HSCs), resulting in their activation, proliferation, differentiation, and matrix deposition. This profibrotic effect of cellular death is balanced by an antifibrotic effect of HSC death. Many HSC survival signals are obtained from the extracellular matrix, and active proapoptotic signals are provided by immune cells, particularly natural killer (NK) cells. Quiescent HSCs are relatively resistant to apoptotic signals but become sensitive after activation. The important role of NK cells in inducing HSC apoptosis may explain the increased fibrosis associated with immune suppression (e.g., in the transplant recipient) and HIV infection. HSCs also undergo senescence, which limits their function and sensitizes them to apoptosis.

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.

Experience of a single center with congenital hepatic fibrosis: A review of the literature

Congenital hepatic fibrosis (CHF) is an autosomal recessive inherited malformation defined pathologically by a variable degree of periportal fibrosis and irregularly shaped proliferating bile ducts. It is one of the fibropolycystic diseases, which also include Caroli disease, autosomal dominant polycystic kidney disease, and autosomal recessive polycystic kidney disease. Clinically it is characterized by hepatic fibrosis, portal hypertension, and renal cystic disease. CHF is known to occur in association with a range of both inherited and non-inherited disorders, with multiorgan involvement, as a result of ductal plate malformation. Because of the similarities in the clinical picture, it is necessary to differentiate CHF from idiopathic portal hypertension and early liver cirrhosis, for which a liver biopsy is essential. Radiological tests are important for recognizing involvement of other organ systems. With regards to our experience at Hacettepe University, a total of 26 patients have been diagnosed and followed-up between 1974 and 2009 with a diagnosis of CHF. Presentation with Caroli syndrome was the most common diagnosis, with all such patients presenting with symptoms of recurrent cholangitis and symptoms related to portal hypertension. Although portal fibrosis is known to contribute to the ensuing portal hypertension, it is our belief that portal vein cavernous transformation also plays an important role in its pathogenesis. In all patients with CHF portal vein morphology should be evaluated by all means since portal vein involvement results in more severe and complicated portal hypertension. Other associations include the Joubert and Bardet-Biedl syndromes.

Diagnosis and treatment of portal hypertension

Major progress has been made in the area of diagnosis and treatment of portal hypertension. Multi-detector row computed tomography (MD-CT) enabled the revelation of the precise overview of portal hemodynamics and was applied into the decision of therapeutic strategies. A noninvasive liver stiffness measurement device, transient elastography, is expected to be applied in the prediction of existence of esophageal varices. Balloon-occluded retrograde transvenous obliteration (B-RTO) is performed mainly in Japan to eradiate the fundic varices and high eradiation rate and low recurrence rate are reported. Partial splenic embolization (PSE) has been performed to improve hypersplenism without serious side-effect and excellent result is reported. Angiotensin receptor blockers (ARBs) are promising drugs for its portal hypotensive effect and antifibrotic effect and more investigation is necessary. Anti-fibrotic therapy, including autologous bone marrow therapy, has the possibility to improve not only liver fibrosis but also portal hypertension.

Influence of angiotensin-converting enzyme I/D gene polymorphism on clinical and histological correlates of chronic hepatitis C

AIM

This study aimed to verify the relationship between the insertion-deletion (I/D) polymorphism of angiotensin-converting enzyme (ACE) and clinical and histological correlates of chronic hepatitis C.

METHODS

Two-hundred and fifty-eight, treatment naive, unselected hepatitis C virus (HCV) RNA-positive patients and 210 controls were studied. ACE allelic variants were determined by polymerase chain reaction.

RESULTS

Mean staging scores adjusted for age, body mass index (BMI) and alcohol consumption were: men, D/* = 2.283; men, I/I = 2.092; women, D/* = 2.241; and women, I/I = 3.283 (P = 0.028). Age-adjusted mean BMI were: men, D/* = 25.01; men, I/I = 24.87; women, D/* = 23.73; and women, I/I = 22.50 (P = 0.006). Age and BMI-adjusted mean low-density lipoprotein (LDL)/ high-density lipoprotein (HDL) cholesterol ratios were: men, D/* = 2.344; men, I/I = 2.283; women, D/* = 1.916; and women, I/I = 1.903 (P = 0.004). Histological grading correlated positively with triglycerides and negatively with HDL and LDL cholesterol (P < 0.0001).

CONCLUSION

Female ACE I/I homozygotes have higher liver fibrosis scores in comparison to D/* women and to men; moreover, they are leaner and have a lower LDL/HDL cholesterol ratio. These observations suggest a possible mutual influence between ACE polymorphism, serum lipid concentrations and outcome of chronic HCV infection.