Effects of the combined administration of propranolol plus sorafenib on portal hypertension in cirrhotic rats

Recent advances in promising drugs for primary prevention of gastroesophageal variceal bleeding with cirrhotic portal hypertension

BACKGROUND

Gastroesophageal variceal bleeding is one of the most severe complications of patients with cirrhosis. Although primary prevention drugs, including non-selective β-blockers, have effectively reduced the incidence of bleeding, their efficacy is limited due to side effects and related contraindications. With recent advances in precision medicine, precise drug treatment provides better treatment efficacy.

DATA SOURCES

Literature search was conducted in PubMed, MEDLINE and Web of Science for relevant articles published up to May 2022. Information on clinical trials was obtained from https://clinicaltrials.gov/ and http://www.chictr.org.cn/.

RESULTS

The in-depth understanding of the pathogenesis and advances of portal hypertension has enabled the discovery of multiple molecular targets for promising drugs. According to the site of action, these drugs could be classified into four classes: intrahepatic, extrahepatic, both intrahepatic and extrahepatic targets and others. All these classes of drugs offer advantages over traditional treatments in prevention of gastroesophageal variceal bleeding in patients with cirrhotic portal hypertension.

CONCLUSIONS

This review classified and summarized the promising drugs, which prevent gastroesophageal variceal bleeding by targeting specific markers of pathogenesis of portal hypertension, demonstrating the significance of using the precision medicine strategy to discover and develop promising drugs for the primary prevention of gastroesophageal variceal bleeding in patients with cirrhotic portal hypertension.

Neuroimmunomodulation of adrenoblockers during liver cirrhosis: modulation of hepatic stellate cell activity

The sympathetic nervous system and the immune system are responsible for producing neurotransmitters and cytokines that interact by binding to receptors; due to this, there is communication between these systems. Liver immune cells and nerve fibres are systematically distributed in the liver, and the partial overlap of both patterns may favour interactions between certain elements. Dendritic cells are attached to fibroblasts, and nerve fibres are connected via the dendritic cell-fibroblast complex. Receptors for most neuroactive substances, such as catecholamines, have been discovered on dendritic cells. The sympathetic nervous system regulates hepatic fibrosis through sympathetic fibres and adrenaline from the adrenal glands through the blood. When there is liver damage, the sympathetic nervous system is activated locally and systemically through proinflammatory cytokines that induce the production of epinephrine and norepinephrine. These neurotransmitters bind to cells through α-adrenergic receptors, triggering a cellular response that secretes inflammatory factors that stimulate and activate hepatic stellate cells. Hepatic stellate cells are key in the fibrotic process. They initiate the overproduction of extracellular matrix components in an active state that progresses from fibrosis to liver cirrhosis. It has also been shown that they can be directly activated by norepinephrine. Alpha and beta adrenoblockers, such as carvedilol, prazosin, and doxazosin, have recently been used to reverse CCl₄-induced liver cirrhosis in rodent and murine models.KEY MESSAGESNeurotransmitters from the sympathetic nervous system activate and increase the proliferation of hepatic stellate cells.Hepatic fibrosis and cirrhosis treatment might depend on neurotransmitter and hepatic nervous system regulation.Strategies to reduce hepatic stellate cell activation and fibrosis are based on experimentation with α-adrenoblockers.

Emerging Therapeutic Targets for Portal Hypertension

Purpose of Review

Portal hypertension is responsible of the main complications of cirrhosis, which carries a high mortality. Recent treatments have improved prognosis, but this is still far from ideal. This paper reviews new potential therapeutic targets unveiled by advances of key pathophysiologic processes.

Recent Findings

Recent research highlighted the importance of suppressing etiologic factors and a safe lifestyle and outlined new mechanisms modulating portal pressure. These include intrahepatic abnormalities linked to inflammation, fibrogenesis, vascular occlusion, parenchymal extinction, and angiogenesis; impaired regeneration; increased hepatic vascular tone due to sinusoidal endothelial dysfunction with insufficient NO availability; and paracrine liver cell crosstalk. Moreover, pathways such as the gut-liver axis modulate splanchnic vasodilatation and systemic inflammation, exacerbate liver fibrosis, and are being targeted by therapy. We have summarized studies of new agents addressing these targets.

Summary

New agents, alone or in combination, allow acting in complementary mechanisms offering a more profound effect on portal hypertension while simultaneously limiting disease progression and favoring regression of fibrosis and of cirrhosis. Major changes in treatment paradigms are anticipated.

Investigational drugs in early clinical development for portal hypertension

INTRODUCTION

Advanced chronic liver disease is considered a reversible condition after removal of the primary aetiological factor. This has led to a paradigm shift in which portal hypertension (PH) is a reversible complication of cirrhosis. The pharmacologic management of PH is centered on finding targets to modify the natural history of cirrhosis and PH.

AREAS COVERED

This paper offers an overview of the use of pharmacological strategies in early clinical development that modify PH. Papers included were selected from searching clinical trials sites and PubMed from the last 10 years.

EXPERT OPINION

A paradigm shift has generated a new concept of PH in cirrhosis as a reversible complication of a potentially curable disease. Decreasing portal pressure to prevent decompensation and further complications of cirrhosis that may lead liver transplantation or death is a goal. Therapeutic strategies also aspire achieve total or partial regression of fibrosis thus eliminating the need for treatment or screening of PH.

Transition to decompensation and acute-on-chronic liver failure: Role of predisposing factors and precipitating events

The transition from compensated to decompensated cirrhosis results from a complex interplay of predisposing and precipitating factors and represents an inflection point in the probability of a patient surviving. With the progression of cirrhosis, patients accumulate multiple disorders (e.g. altered liver architecture, portal hypertension, local and systemic inflammation, bacterial translocation, gut dysbiosis, kidney vasoconstriction) that predispose them to decompensation. On the background of these factors, precipitating events (e.g. bacterial infection, alcoholic hepatitis, variceal haemorrhage, drug-induced liver injury, flare of liver disease) lead to acute decompensation (ascites, hepatic encephalopathy, variceal bleeding, jaundice) and/or organ failures, which characterise acute-on-chronic liver failure. In this review paper, we will discuss the current hypotheses and latest evidences regarding predisposing and precipitating factors associated with the transition to decompensated liver disease.

Angiogenesis in the progression from liver fibrosis to cirrhosis and hepatocelluar carcinoma

Introduction: Persistent inflammation and hypoxia are strong stimulus for pathological angiogenesis and vascular remodeling, and are also the most important elements resulting in liver fibrosis. Sustained inflammatory process stimulates fibrosis to the end-point of cirrhosis and sinusoidal portal hypertension is an important feature of cirrhosis. Neovascularization plays a pivotal role in collateral circulation formation of portal vein, mesenteric congestion, and high perfusion. Imbalance of hepatic artery and portal vein blood flow leads to the increase of hepatic artery inflow, which is beneficial to the formation of nodules. Angiogenesis contributes to progression from liver fibrosis to cirrhosis and hepatocellular carcinoma (HCC) and anti-angiogenesis therapy can improve liver fibrosis, reduce portal pressure, and prolong overall survival of patients with HCC. Areas covers: This paper will try to address the difference of the morphological characteristics and mechanisms of neovascularization in the process from liver fibrosis to cirrhosis and HCC and further compare the different efficacy of anti-angiogenesis therapy in these three stages. Expert opinion: More in-depth understanding of the role of angiogenesis factors and the relationship between angiogenesis and other aspects of the pathogenesis and transformation may be the key to enabling future progress in the treatment of patients with liver fibrosis, cirrhosis, and HCC.

Propranolol Suppresses the T-Helper Cell Depletion-Related Immune Dysfunction in Cirrhotic Mice

Bacterial translocation (BT) and splenomegaly contribute to cirrhosis-associated immune dysfunction (CAID) including T cell depletion, infection, and chronic inflammation. β-blockers have been reported to decrease BT and improve splenomegaly. This study explores the modulation of β1 and β2 adrenergic receptors (ADRB1/ADRB2) by propranolol treatment on the peripheral and splenic immune dysfunction of cirrhotic mice. In vivo experiments were performed in bile duct ligation (BDL)- and thioacetamide (TAA)-cirrhotic mice receiving two weeks of propranolol treatment. Acute effects of propranolol were evaluated in T-helper (Th) cells isolated from spleen of cirrhotic mice. Over-expression of β1 and β2 adrenergic receptors (ADRB1/ADRB2) in spleen and T lymphocytes was associated with high peripheral/splenic lipopolysaccharide binding protein levels. Moreover, a decrease in Th cells percentage, increase in Treg subset, and cytokines were accompanied by increased apoptosis, proliferation, and reduced white pulp hyperplasia in cirrhotic mice, which were counteracted by propranolol treatment. The Th-cell depletion, systemic inflammation, BT, and infection were improved by chronic propranolol treatment. Acute propranolol treatment inhibited apoptosis, Treg-conditioned differentiation, and promoted Th2-conditioned differentiation through ADRB-cyclic adenosine monophosphate (cAMP) signals in cirrhotic mice. In conclusion, suppression of ADRB1 and ADRB2 expressions in spleen and splenic T lymphocytes by acute and chronic propranolol treatment ameliorate systemic and splenic immune dysfunction in cirrhosis.

Pharmacologic Management of Portal Hypertension

Terlipressin, somatostatin, or octreotide are recommended as pharmacologic treatment of acute variceal hemorrhage. Nonselective β-blockers decrease the risk of variceal hemorrhage and hepatic decompensation, particularly in those 30% to 40% of patients with good hemodynamic response. Carvedilol, statins, and anticoagulants are promising agents in the management of portal hypertension. Recent advances in the pharmacologic treatment of portal hypertension have mainly focused on modifying an increased intrahepatic resistance through nitric oxide and/or modulation of vasoactive substances. Several novel pharmacologic agents for portal hypertension are being evaluated in humans.

Hepatic microcirculation and mechanisms of portal hypertension

The liver microcirculatory milieu, mainly composed of liver sinusoidal endothelial cells (LSECs), hepatic stellate cells (HSCs) and hepatic macrophages, has an essential role in liver homeostasis, including in preserving hepatocyte function, regulating the vascular tone and controlling inflammation. Liver microcirculatory dysfunction is one of the key mechanisms that promotes the progression of chronic liver disease (also termed cirrhosis) and the development of its major clinical complication, portal hypertension. In the present Review, we describe the current knowledge of liver microcirculatory dysfunction in cirrhotic portal hypertension and appraise the preclinical models used to study the liver circulation. We also provide a comprehensive summary of the promising therapeutic options to target the liver microvasculature in cirrhosis.

Antiangiogenic therapy for portal hypertension in liver cirrhosis: Current progress and perspectives

Developing medicines for hemodynamic disorders that are characteristic of cirrhosis of the liver is a relevant problem in modern hepatology. The increase in hepatic vascular resistance to portal blood flow and subsequent hyperdynamic circulation underlie portal hypertension (PH) and promote its progression, despite the formation of portosystemic collaterals. Angiogenesis and vascular bed restructurization play an important role in PH pathogenesis as well. In this regard, strategic directions in the therapy for PH in cirrhosis include selectively decreasing hepatic vascular resistance while preserving or increasing portal blood flow, and correcting hyperdynamic circulation and pathological angiogenesis. The aim of this review is to describe the mechanisms of angiogenesis in PH and the methods of antiangiogenic therapy. The PubMed database, the Google Scholar retrieval system, and the reference lists from related articles were used to search for relevant publications. Articles corresponding to the aim of the review were selected for 2000-2017 using the keywords: “liver cirrhosis”, “portal hypertension”, “pathogenesis”, “angiogenesis”, and “antiangiogenic therapy”. Antiangiogenic therapy for PH was the inclusion criterion. In this review, we have described angiogenesis inhibitors and their mechanism of action in relation to PH. Although most of them were studied only in animal experiments, this selective therapy for abnormally growing newly formed vessels is pathogenetically reasonable to treat PH and associated complications.

An in-depth review of chemical angiogenesis inhibitors for treating hepatocellular carcinoma

INTRODUCTION

Hepatocellular carcinoma (HCC) is a frequent and severe complication of cirrhosis. Most HCC patients initially present with or progress to advanced stage disease and require systemic treatment. As hypervascularization is a major characteristic of HCC, antiangiogenic drugs have been tested. Areas covered: In this review, we summarize data on the use of drugs targeting the angiogenesis. Despite many trials, in 2017 only 3 drugs, all antiangiogenic, have demonstrated efficacy in first (sorafenib, lenvatinib) or second line (regorafenib) treatment of advanced HCC. The heterogeneous mechanisms of action and the major reasons for failure of most trials are discussed. An English-language, abstract-based literature review was performed by a PubMed-based strategy. Expert opinion: Currently all trials based on purely antiangiogenic compounds (bevacizumab, linifanib, brivanib and ramucirumab) or drugs with strong antiangiogenic properties (sunitinib) have failed (increased toxicity, minor efficacy and/or flaws in trial design); sorafenib, lenvatinib and regorafenib are multityrosine kinase inhibitors and their efficacy can be partly related to another mechanism of action. We need to better refine future trials design (randomized phase 2, good stratification factors and marker-enriched patient selection) in order to progress toward customized treatment, perhaps in association with immunotherapy.

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.

Angiogenesis and portal-systemic collaterals in portal hypertension

In patients with advanced liver disease with portal hypertension, portal-systemic collaterals contribute to circulatory disturbance, gastrointestinal hemorrhage, hepatic encephalopathy, ascites, hepatopulmonary syndrome and portopulmonary hypertension. Angiogenesis has a pivotal role in the formation of portal-systemic shunts. Recent research has defined many of the mediators and mechanisms involved in this angiogenic process, linking the central roles of hepatic stellate cells and endothelial cells. Studies of animal models have demonstrated the potential therapeutic impact of drugs to inhibit angiogenesis in cirrhosis. For example, inhibition of VEGF reduces portal pressure, hyperdynamic splanchnic circulation, portosystemic collateralization and liver fibrosis. An improved understanding of the role of other angiogenic factors provides hope for a novel targeted therapy for portal hypertension with a tolerable adverse effect profile.

Advances in the treatment of portal hypertension in cirrhosis

Non-selective beta-blockers and handling of esophageal varices has been key elements in the treatment of portal hypertension in recent decades. Liver vein catheterization has been essential in diagnosis and monitoring of portal hypertension, but ongoing needs for noninvasive tools has led to research in areas of both biomarkers, and transient elastography, which displays promising results in discerning clinically significant portal hypertension. Novel research into the areas of hepatic stellate cell function and the dynamic components of portal hypertension has revealed promising areas of treatment modalities, targeting intestinal decontamination, angiogenesis, inflammation and oxidative stress. Future studies may reveal if these initiatives lead to developments of new drugs for treatment of portal hypertension.

Emerging therapies for portal hypertension in cirrhosis

INTRODUCTION

Counteracting splanchnic vasodilatation and increased portal-collateral blood flow has been the mainstay for the treatment of portal hypertension (PH) over the past three decades. However, there is still large room for improvement in the treatment of PH.

AREAS COVERED

The basic mechanism leading to portal hypertension is the increased hepatic vascular resistance to portal blood flow caused by liver structural abnormalities inherent to cirrhosis and increased hepatic vascular tone. Molecules modulating microvascular dysfunction which have undergone preclinical and clinical trials are summarized, potential drug development issues are addressed, and situations relevant to design of clinical trials are considered.

EXPERT OPINION

Experimental and clinical evidence indicates that molecules modulating liver microvascular dysfunction may allow for 30-40% reduction in portal pressure. Several agents could be utilized in the earlier stages of cirrhosis (antifibrotics, antiangiogenics, etiological therapies) may allow reduction of fibrosis and halt progression of PH. This 'nip at the bud' policy, by combining therapies with existing agents used in advanced phase of cirrhosis and novel agents which could be used in early phase of cirrhotic spectrum, which are likely to hit the market soon would be the future strategy for PH therapy.

[Aspects of pathogenetc pharmacotherapy for portal hypertension in liver cirrhosis]

The review of literature considers the principles of medical treatment for portal hypertension in liver cirrhosis, which are based on the current views of its development mechanisms. It describes both current pharmacotherapy methods for portal hypertension and drugs, the efficacy of which is being investigated.

Combined administration of propranolol + AG490 offers better effects on portal hypertensive rats with cirrhosis

BACKGROUND AND AIMS

AG490, the specific inhibitor of JAK2/STAT3 signaling, has been shown to decrease portal pressure, splanchnic hyperdynamic circulation and liver fibrosis in cirrhotic rats. Nonselective betablockers such as propranolol are the only drugs recommended in the treatment of portal hypertension. The aim of this study was to explore the combinative effect of treatment with propranolol and AG490 on portal hypertension.

METHODS

Rats induced by common bile duct ligation were treated with vehicle, AG490, propranolol, or AG490 + propranolol for 2 weeks. Hemodynamics parameters were assessed. Expressions of phospho-STAT3 protein and its down-regulated cytokines in splanchnic organs were detected by ELISA or western blot. Lipopolysaccharide binding protein (LBP) and IL-6 were assessed by ELISA or western blot. Characterization of liver and mesentery was performed by histological analyses.

RESULTS

Highly expressed phospho-STAT3 protein in cirrhotic rats could successfully be inhibited by AG490 or AG490 + propranolol treatments but not by propranolol alone. Both AG490 and propranolol significantly reduced portal pressure and hyperdynamic splanchnic circulation, and combination of AG490 and propranolol achieved an additive effect than with either drug alone. AG490, alone or in combination with propranolol, inhibited liver fibrosis, splenomegaly and splanchnic angiogenesis. Increased markers of bacterial translocation (LBP and IL6) were greatly reduced by propranolol but not by AG490.

CONCLUSIONS

The combination of propranolol and AG490 caused a greater improvement of portal hypertension and might therefore offer a potentially promising therapy in the portal hypertension treatment.

Cancer and liver cirrhosis: implications on prognosis and management

Liver cirrhosis, the end-stage of every chronic liver disease, is not only the major risk factor for the development of hepatocellular carcinoma but also a limiting factor for anticancer therapy of liver and non-hepatic malignancies. Liver cirrhosis may limit surgical and interventional approaches to cancer treatment, influence pharmacokinetics of anticancer drugs, increase side effects of chemotherapy, render patients susceptible for hepatotoxicity, and ultimately result in a competitive risk for morbidity and mortality. In this review, we provide a concise overview about the impact of liver cirrhosis on the management and prognosis of patients with primary liver cancer or non-hepatic malignancies.

Pathophysiology and a Rational Basis of Therapy

Portal hypertension is a common complication of chronic liver disease. Its relevance comes from the fact that it determines most complications leading to death or liver transplantation in patients with cirrhosis of the liver: bleeding from esophageal or gastric varices, ascites and renal dysfunction, sepsis and hepatic encephalopathy. Portal hypertension results from increased resistance to portal blood flow through the cirrhotic liver. This is caused by two mechanisms: (1) distortion of the liver vascular architecture due to the liver disease causing structural abnormalities (nodule formation, remodeling of liver sinusoids, fibrosis, angiogenesis and vascular occlusion), and (2) increased hepatic vascular tone due to sinusoidal endothelial dysfunction, which results in a defective production of endogenous vasodilators, mainly nitric oxide (NO), and increased production of vasoconstrictors (thromboxane A2, cysteinyl leukotrienes, angiotensin II, endothelins and an activated adrenergic system). Hepatic endothelial dysfunction occurs early in the course of chronic liver disease as a consequence of inflammation and oxidative stress, and determines loss of the normal phenotype of liver sinusoidal endothelial cells (LSECs) that become proliferative, prothrombotic, proinflammatory and vasoconstrictor. The cross-talk between LSECs and hepatic stellate cells (HSCs) induces activation of the latter, which in turn proliferate, migrate and increase collagen deposition around the sinusoids, contributing to fibrogenesis, architectural disruption and angiogenesis, which further increase the hepatic vascular resistance and worsen liver failure by interfering with the blood perfusion of the liver parenchyma. An additional factor further worsening portal hypertension is an increased blood flow through the portal system due to splanchnic vasodilatation. This is an adaptive response to decreased effective hepatocyte perfusion, and is maximal once portal pressure has increased sufficiently to promote the development of intrahepatic shunts and portal-systemic collaterals, including varices, through which portal blood flow bypasses the liver. In human portal hypertension collateralization and hyperdynamic circulation start at a portal pressure gradient >10 mm Hg. Rational therapy for portal hypertension aims at correcting these pathophysiological abnormalities: liver injury, fibrogenesis, increased hepatic vascular tone and splanchnic vasodilatation. Continuing liver injury may be counteracted specifically by etiological treatments (the best example being the direct-acting antivirals for hepatitis C viral infection), while architectural disruption and fibrosis can be ameliorated by a variety of antifibrotic drugs and antiangiogenic strategies. Several drugs in this category are currently under investigation in phase II-III randomized controlled trials. Sinusoidal endothelial dysfunction is ameliorated by statins as well as by other drugs increasing NO availability. It is of note that simvastatin has already been proven to be clinically effective in two randomized controlled trials. Splanchnic hyperemia can be counteracted by nonselective β-blockers (NSBBs), vasopressin analogs and somatostatin analogs, drugs that until recently were the only available treatments for portal hypertension, but that are not very effective in the initial stages of cirrhosis. There is experimental and clinical evidence indicating that a more effective reduction of portal pressure is obtained by combining agents acting on these different pathways. It is likely that the treatment of portal hypertension will evolve to use etiological treatments together with antifibrotic agents and/or drugs improving sinusoidal endothelial function in the initial stages of cirrhosis (preprimary prophylaxis), while NSBBs will be added in advanced stages of the disease.

Contemporary concepts of the medical therapy of portal hypertension under liver cirrhosis

Severe complications of liver cirrhosis are mostly related to portal hypertension. At the base of the pathogenesis of portal hypertension is the increase in hepatic vascular resistance to portal blood flow with subsequent development of hyperdynamic circulation, which, despite of the formation of collateral circulation, promotes progression of portal hypertension. An important role in its pathogenesis is played by the rearrangement of vascular bed and angiogenesis. As a result, strategic directions of the therapy of portal hypertension under liver cirrhosis include selectively decreasing hepatic vascular resistance with preserving or increasing portal blood flow, and correcting hyperdynamic circulation and pathological angiogenesis, while striving to reduce the hepatic venous pressure gradient to less than 12 mmHg or 20% of the baseline. Over the last years, substantial progress in understanding the pathophysiological mechanisms of hemodynamic disorders under liver cirrhosis has resulted in the development of new drugs for their correction. Although the majority of them have so far been investigated only in animal experiments, as well as at the molecular and cellular level, it might be expected that the introduction of the new methods in clinical practice will increase the efficacy of the conservative approach to the prophylaxis and treatment of portal hypertension complications. The purpose of the review is to describe the known methods of portal hypertension pharmacotherapy and discuss the drugs that may affect the basic pathogenetic mechanisms of its development.

New cellular and molecular targets for the treatment of portal hypertension

Portal hypertension (PH) is a common complication of chronic liver disease, and it determines most complications leading to death or liver transplantation in patients with liver cirrhosis. PH results from increased resistance to portal blood flow through the cirrhotic liver. This is caused by two mechanisms: (a) distortion of the liver vascular architecture and (b) hepatic microvascular dysfunction. Increment in hepatic resistance is latterly accompanied by splanchnic vasodilation, which further aggravates PH. Hepatic microvascular dysfunction occurs early in the course of chronic liver disease as a consequence of inflammation and oxidative stress and determines loss of the normal phenotype of liver sinusoidal endothelial cells (LSEC). The cross-talk between LSEC and hepatic stellate cells induces activation of the latter, which in turn proliferate, migrate and increase collagen deposition around the sinusoids, contributing to fibrogenesis, architectural disruption and angiogenesis. Therapy for PH aims at correcting these pathophysiological abnormalities: liver injury, fibrogenesis, increased hepatic vascular tone and splanchnic vasodilatation. Continuing liver injury may be counteracted specifically by etiological treatments, while architectural disruption and fibrosis can be ameliorated by a variety of anti-fibrogenic drugs and anti-angiogenic strategies. Sinusoidal endothelial dysfunction is ameliorated by statins and other drugs increasing NO availability. Splanchnic hyperemia can be counteracted by non-selective beta-blockers (NSBBs), vasopressin analogs and somatostatin analogs. Future treatment of portal hypertension will evolve to use etiological treatments together with anti-fibrotic agents and/or drugs improving microvascular function in initial stages of cirrhosis (pre-primary prophylaxis), while NSBBs will be added in advanced stages of the disease.

Angiogenesis and liver fibrosis

Recent data indicate that hepatic angiogenesis, regardless of the etiology, takes place in chronic liver diseases (CLDs) that are characterized by inflammation and progressive fibrosis. Because anti-angiogenic therapy has been found to be efficient in the prevention of fibrosis in experimental models of CLDs, it is suggested that blocking angiogenesis could be a promising therapeutic option in patients with advanced fibrosis. Consequently, efforts are being directed to revealing the mechanisms involved in angiogenesis during the progression of liver fibrosis. Literature evidences indicate that hepatic angiogenesis and fibrosis are closely related in both clinical and experimental conditions. Hypoxia is a major inducer of angiogenesis together with inflammation and hepatic stellate cells. These profibrogenic cells stand at the intersection between inflammation, angiogenesis and fibrosis and play also a pivotal role in angiogenesis. This review mainly focuses to give a clear view on the relevant features that communicate angiogenesis with progression of fibrosis in CLDs towards the-end point of cirrhosis that may be translated into future therapies. The pathogenesis of hepatic angiogenesis associated with portal hypertension, viral hepatitis, non-alcoholic fatty liver disease and alcoholic liver disease are also discussed to emphasize the various mechanisms involved in angiogenesis during liver fibrogenesis.

Comparative portal hypotensive effects as propranolol of vitamin D₃ treatment by decreasing intrahepatic resistance in cirrhotic rats

BACKGROUND AND AIM

Vitamin D₃ improves portal hypertension (PH) through the activation of vitamin D receptor (VDR) and calcium-sensing receptor (CaSR) in cirrhotic rats. Propranolol is a non-selective β-blocker that is recommended for the treatment of PH. The present study aims to investigate the detail systemic and hepatic mechanisms of vitamin D₃ and propranolol, alone or in combination, in cirrhotic rats.

METHODS

Common bile duct-ligated and thioacetamide cirrhotic rats were treated with vehicle, propranolol (30 mg/kg/day), vitamin D₃ (0.5 μg/100 g/day, twice weekly), or propranolol + vitamin D₃, separately.

RESULTS

Significantly, propranolol and vitamin D₃ produced a similar magnitude of reduction in portal venous pressure (PVP) in cirrhotic rats through different mechanisms: whereas propranolol decreased PVP by reducing splanchnic hyperemia and cardiac index, vitamin D₃ decreased PVP by decreasing intrahepatic resistance (IHR). However, propranolol + vitamin D₃ did not further decrease PVP in cirrhotic rats. Notably, a marked decrease in hepatic VDR and CaSR expressions was noted in cirrhotic human/rat livers compared with non-cirrhotic human/rat livers. In cirrhotic rats, vitamin D₃ administration decreasing IHR by inhibiting the renin-angiotensin system, hepatic oxidative stress, inflammation/fibrosis, angiotensin II (ANGII) production, CaSR-mediated ANGII hyperresponsiveness, ANGII-induced hepatic stellate cells contraction, and correcting hepatic endothelial dysfunction through upregulation of hepatic VDR, CaSR, and endothelial nitric oxide synthase expressions.

CONCLUSION

Chronic vitamin D₃ treatment alone results in comparative portal hypotensive effects as propranolol alone in cirrhotic rats with PH. Taken together, chronic vitamin D₃ administration was an ideal alternative strategy to effectively improve PH without unwanted systemic side-effects.

Sorafenib ameliorates renal fibrosis through inhibition of TGF-β-induced epithelial-mesenchymal transition

Objective

This study was to investigate whether sorafenib can inhibit the progression of renal fibrosis and to study the possible mechanisms of this effect.

Methods

Eight-week-old rats were subjected to unilateral ureteral obstruction (UUO) and were intragastrically administered sorafenib, while control and sham groups were administered vehicle for 14 or 21 days. NRK-52E cells were treated with TGF-β1 and sorafenib for 24 or 48 hours. HE and Masson staining were used to visualize fibrosis of the renal tissue in each group. The expression of α-SMA and E-cadherin in kidney tissue and NRK-52E cells were performed using immunohistochemistry and immunofluorescence. The apoptosis rate of NRK-52E cells was determined by flow cytometry analysis. The protein levels of Smad3 and p-Smad3 in kidney tissue and NRK-52E cells were detected by western blot analysis.

Results

HE staining demonstrated that kidney interstitial fibrosis, tubular atrophy, and inflammatory cell infiltration in the sorafenib-treated-UUO groups were significantly decreased compared with the vehicle-treated-UUO group (p<0.05). Masson staining showed that the area of fibrosis was significantly decreased in the sorafenib-treated-UUO groups compared with vehicle-treated-UUO group (p<0.01). The size of the kidney did not significantly increase; the cortex of the kidney was thicker and had a richer blood supply in the middle-dose sorafenib group compared with the vehicle-treated-UUO group (p<0.05). Compared with the vehicle-treated-UUO and TGF-β-stimulated NRK-52E groups, the expression of a-SMA and E-cadherin decreased and increased, respectively, in the UUO kidneys and NRK-52E cells of the sorafenib-treated groups (p<0.05). The apoptotic rate of NRK-52E cells treated with sorafenib decreased for 24 hours in a dose-dependent manner (p<0.05). Compared with the vehicle-treated UUO and TGF-β-stimulated NRK-52E groups, the ratio of p-Smad3 to Smad3 decreased in the sorafenib-treated groups (p<0.05).

Conclusion

Our results suggest that sorafenib may useful for the treatment of renal fibrosis through the suppression of TGF-β/Smad3-induced EMT signaling.

The use of propranolol in the treatment of infantile haemangiomas: an update on potential mechanisms of action

Currently, propranolol is the preferred treatment for problematic proliferating infantile haemangiomas (IHs). The rapid action of propranolol has been shown to be especially dramatic in IHs involving dyspnoea, haemodynamic compromise, palpebral occlusion or ulceration. Another remarkable aspect of propranolol treatment revealed that the growth of the IHs was not only stabilized, but also that the improvement continued until complete involution was achieved, leading to a considerable shortening of the natural course of IH. However, the mechanisms underlying the effects of propranolol have not been fully elucidated. Recent studies have offered evidence of a variety of mechanisms. These include the promotion of pericyte-mediated vasoconstriction, the inhibition of vasculogenesis and catecholamine-induced angiogenesis, the disruption of haemodynamic force-induced cell survival, and the inactivation of the renin-angiotensin system. This review summarizes these mechanisms and the new concepts that are emerging in this area of research. Moreover, several molecular mechanisms by which propranolol may modify neovascularization in IH have also been proposed. The antihaemangioma effect of propranolol may not be attributable to a single mechanism, but rather to a combination of events that have not yet been elucidated or understood. Further studies are needed to evaluate and verify these mechanisms to gain a greater understanding of the effects of the intake of propranolol on haemangioma involution.

Future therapy of portal hypertension in liver cirrhosis - a guess

In patients with chronic liver disease, portal hypertension is driven by progressive fibrosis and intrahepatic vasoconstriction. Interruption of the initiating and perpetuating etiology—mostly leading to necroinflammation—is possible for several underlying causes, such as autoimmune hepatitis, hepatitis B virus (HBV) infection, and most recently hepatitis C virus (HCV) infection. Thus, in the long run, lifestyle-related liver damage due to chronic alcoholism or morbid obesity will remain the main factor leading to portal hypertension. Both causes are probably more easily countered by socioeconomic measures than by individual approaches. If chronic liver injury supporting fibrogenesis and portal hypertension cannot be interrupted, a wide variety of tools are available to modulate and reduce intrahepatic resistance and therewith portal hypertension. Many of these have been evaluated in animal models. Also, some well-established drugs, which are used in humans for other indications (for example, statins), are promising if applied early and concomitantly to standard therapy. In the future, more individually tailored strategies must also be considered in line with the spectrum of portal hypertensive complications and risk factors defined by high-throughput analysis of the patient’s genome, transcriptome, metabolome, or microbiome.

Beneficial effects of dual vascular endothelial growth factor receptor/fibroblast growth factor receptor inhibitor brivanib alaninate in cirrhotic portal hypertensive rats

BACKGROUND AND AIM

Vascular endothelial (VEGF) and fibroblast growth factor (FGF)-induced hepatic stellate (HSCs) and liver endothelial cells (LECs) activation accelerates hepatic fibrogenesis and angiogenesis, and hemodynamic dysarrangements in cirrhosis. VEGF targeting agents had been reported as potential drugs for cirrhosis. However, the evaluation of effects of dual VEGF/FGF targeting agent in cirrhosis is still limited.

METHODS

Using hemodynamic parameters, blood chemistry, primary isolated HSCs and LECs, histology, and digital imaging, we assess the effects of 2-week brivanib alaninate, a dual VEGFR/FGFR inhibitor, treatment in the pathophysiology of bile duct-ligated-cirrhotic rats.

RESULTS

Fibrogenic and angiogenic markers in the serum and liver of bile duct-ligated-cirrhotic rats, including hydroxyproline, transforming growth factor-β1, angiopoietin-1, VEGF, FGF-2, endocan and phosphorylated-VEGFR2/VEGFR2, and phosphorylated-FGFR/FGFR together with hepatic CD31/angiopoietin-1 expressions (immunohistochemistry staining), angiogenesis (micro-computed tomography scan), microcirculatory dysfunction (in vivo miscroscopy and in situ liver perfusion study), portal hypertension, and hyperdynamic circulations (colored microsphere methods) were markedly suppressed and ameliorated by brivanib alaninate treatment. In in vitro study, acute brivanib alaninate incubation inhibited the transforming growth factor-β1-induced HSCs contraction/migration and VEGF-induced LECs angiogenesis. Concomitantly, the overexpression of various fibrogenic and angiogenic markers in HSCs and LECs, and in their culture media, was increased in parallel and these changes were suppressed by acute brivanib alaninate incubation.

CONCLUSIONS

This study demonstrated that brivanib alaninate targeting multiple mechanisms and working in the different pathogenic steps of the complications of cirrhotic rats with portal hypertension.

Anti-VEGFR agents ameliorate hepatic venous dysregulation/microcirculatory dysfunction, splanchnic venous pooling and ascites of NASH-cirrhotic rat

BACKGROUND & AIMS

Antivascular endothelial growth factor receptor (VEGFR) agents improve hepatic fibrosis and portal hypertension in cirrhosis. Detail interactions among recruited/activated leucocytes, hepatic angiogenesis and fibrogenesis, splanchnic blood pooling, decreased hepatic veins to fluctuated splanchnic blood volume (hepatic venous dysregulation), portal hypertensive syndrome and ascites have never explored in cirrhosis. Our study used two anti-VEGFR agents - brivanib and sorafenib - to elucidate the relationship between above abnormalities of nonalcoholic steatohepatitis (NASH)-cirrhotic rats.

MATERIALS AND METHODS

NASH-cirrhotic rats received 2-week brivanib, sorafenib or vehicle (NASH-cirrhotic+briv, NASH-cirrhotic+soraf and NASH-cirrhotic rats) were included for various measurements.

RESULTS

In comparison with NASH-cirrhotic rats, significant decreased plasma VEGF, fibroblast growth factor, platelet-derived growth factor, hepatic tumour necrosis factor (TNFα), IL-1β, IL-6, IL-17 were accompanied by decreased leucocyte mass/activity ((99 m) Tc-phytate and (18) F-FDG SPECT/PET/CT scans), hepatic leucocytes recruitment/microvascular density (fluorescence-enhanced intravital microscopy) and hydroxyproline content, and increased hepatic blood flow in NASH-cirrhotic+briv and NASH-cirrhotic+soraf rats. In addition, increased hepatic microvasculatures compliance-related improved buffering effect of portal vein to acute mannitol infusion was associated with decreased circulating nitric oxide and aldosterone, plasma volume expansion (dye dilution method), splanchnic blood pooling ((99 m) Tc-RBC SPECT/PET/CT scans), peripheral hypotension, portal hypertension and ascites in brivanib and sorafenib-treated NASH-cirrhotic rats.

CONCLUSION

Besides antifibrotic, antiangiogenic and portal hypertensive effects, chronic antagonism of anti-VEGFR with brivanib and sorafenib improves hepatic blood flow, hepatic venous dysregulation, inhibits leucocytes recruitment/activation, splanchnic blood pooling and ascites formation in NASH-cirrhotic rats. Thus, brivanib and sorafenib might be ideal therapeutic agents in cirrhotic patients suffering from severe haemodynamic disarrangement and ascites.

Rebleeding prophylaxis improves outcomes in patients with hepatocellular carcinoma. A multicenter case-control study

Outcome of variceal bleeding (VB) in patients with hepatocellular carcinoma (HCC) is unknown. We compared outcomes after VB in patients with and without HCC. All patients with HCC and esophageal VB admitted between 2007 and 2010 were included. Follow-up was prolonged until death, transplantation, or June 2011. For each patient with HCC, a patient without HCC matched by age and Child-Pugh class was selected. A total of 292 patients were included, 146 with HCC (Barcelona Classification of Liver Cancer class 0-3 patients, A [in 25], B [in 29], C [in 45], and D [in 41]) and 146 without HCC. No differences were observed regarding previous use of prophylaxis, clinical presentation, endoscopic findings, and initial endoscopic treatment. Five-day failure was similar (25% in HCC versus 18% in non-HCC; P = 0.257). HCC patients had greater 6-week rebleeding rate (16 versus 7%, respectively; P = 0.025) and 6-week mortality (30% versus 15%; P = 0.003). Fewer patients with HCC received secondary prophylaxis after bleeding (77% versus 89%; P = 0.009), and standard combination therapy was used less frequently (58% versus 70%; P = 0.079). Secondary prophylaxis failure was more frequent (50% versus 31%; P = 0.001) and survival significantly shorter in patients with HCC (median survival: 5 months versus greater than 38 months in patients without HCC; P < 0.001). Lack of prophylaxis increased rebleeding and mortality. On multivariate analysis Child-Pugh score, presence of HCC, portal vein thrombosis, and lack of secondary prophylaxis were predictors of death.

CONCLUSIONS

Patients with HCC and VB have worse prognosis than patients with VB without HCC. Secondary prophylaxis offers survival benefit in HCC patients.