Evolution in the understanding of the pathophysiological basis of portal hypertension: How changes in paradigm are leading to successful new treatments

Preventing the progression of cirrhosis to decompensation and death

Two main stages are differentiated in patients with advanced chronic liver disease (ACLD), one compensated (cACLD) with an excellent prognosis, and the other decompensated (dACLD), defined by the appearance of complications (ascites, variceal bleeding and hepatic encephalopathy) and associated with high mortality. Preventing the progression to dACLD might dramatically improve prognosis and reduce the burden of care associated with ACLD. Portal hypertension is a major driver of the transition from cACLD to dACLD, and a portal pressure of ≥10 mmHg defines clinically significant portal hypertension (CSPH) as the threshold from which decompensating events may occur. In recent years, innovative studies have provided evidence supporting new strategies to prevent decompensation in cACLD. These studies have yielded major advances, including the development of noninvasive tests (NITs) to identify patients with CSPH with reasonable confidence, the demonstration that aetiological therapies can prevent disease progression and even achieve regression of cirrhosis, and the finding that non-selective β-blockers can effectively prevent decompensation in patients with cACLD and CSPH, mainly by reducing the risk of ascites, the most frequent decompensating event. Here, we review the evidence supporting new strategies to manage cACLD to prevent decompensation and the caveats for their implementation, from patient selection using NITs to ancillary therapies.

Platelet activation relieves liver portal hypertension via the lymphatic system though the classical vascular endothelial growth factor receptor 3 signaling pathway

BACKGROUND

Liver cirrhosis and portal hypertension (PHT) can lead to lymphatic abnormalities and coagulation dysfunction. Because lymphangiogenesis may relieve liver cirrhosis and PHT, the present study investigated the gene expression alterations in the lymphatic system and the effectiveness of platelet-mediated lymphangiogenesis in improving liver cirrhosis and PHT.

AIM

To investigate the role of lymphangiogenesis in preclinical PHT models.

METHODS

Immunohistochemistry and transcriptome sequencing of bile duct ligation (BDL) and control lymphatic samples were conducted to reveal the indicated signaling pathways. Functional enrichment analyses were performed on the differentially expressed genes and hub genes. Adenoviral infection of vascular endothelial growth factor C (VEGF-C), platelet-rich plasma (PRP), and VEGF3 receptor (VEGFR) inhibitor MAZ-51 was used as an intervention for the lymphatic system in PHT models. Histology, hemodynamic tests and western blot analyses were performed to demonstrate the effects of lymphatic intervention in PHT patients.

RESULTS

Lymphangiogenesis was increased in the BDL rat model. Transcriptome sequencing analysis of the extrahepatic lymphatic system revealed its close association with platelet adherence, aggregation, and activation. The role of PHT in the rat model was investigated by activating (PRP) and inhibiting (MAZ-51) the lymphatic system. PRP promoted lymphangiogenesis, which increased lymphatic drainage, alleviated portal pressure, reduced liver fibrosis, inhibited inflammation, inhibited angiogenesis, and suppressed mesenteric artery remodeling. MAZ-51 reversed the above improvements.

CONCLUSION

Via VEGF-C/VEGFR-3, platelets impede fibrosis, angiogenesis, and mesenteric artery remodeling, ultimately alleviating PHT. Thus, platelet intervention is a therapeutic approach for cirrhosis and PHT.

Non-invasive assessment of portal hypertension: Liver stiffness and beyond

Portal hypertension (PH) leads to life-threatening clinical manifestations such as bleeding from gastro-oesophageal varices, ascites and its complications, and portosystemic encephalopathy. It can develop because of advanced chronic liver disease (ACLD) or due to rarer causes such as vascular liver disease. Reference standard methods to assess PH in ACLD include the measurement of hepatic venous pressure gradient and endoscopy, which have limitations due to their high resource utilisation and invasiveness. Non-invasive tests (NITs) have entered clinical practice and allow invasive procedures to be reserved for patients with indeterminate findings on NITs or for specific clinical questions. In this review, we present an update on the role of NITs, and in particular ultrasound elastography, to diagnose PH in ACLD and vascular liver disease, and to stratify the risk of liver-related events. We also provide insights into the open research questions and design of studies in this field.

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.

Cilostazol counteracts mitochondrial dysfunction in hepatic encephalopathy rat model: Insights into the role of cAMP/AMPK/SIRT1/ PINK-1/parkin hub and p-CREB /BDNF/ TrkB neuroprotective trajectory

A devasting stage of chronic hepatic dysfunction is strictly correlated with neurological impairment, signifying hepatic encephalopathy (HE). HE is a multifactorial condition; therefore, hyperammonemia, oxidative stress, neuroinflammation, and mitochondrial dysfunction interplay in HE's progressive development. Cilostazol (Cilo) has shown promising neuroprotective and hepatoprotective effectiveness in different neuronal and hepatic disorders; however, its efficiency against HE hasn't yet been explored. This study aimed to investigate the protective role of Cilo against thioacetamide (TAA)-induced HE in rats targeting mitochondrial dysfunction via modulation of Adenosine monophosphate-activated protein kinase (AMPK)/Silent information regulator 1 (SIRT1) dependent pathways. Rats were allocated into three groups: the normal control group, the TAA group received (100 mg/kg, three times per week, for six weeks) to induce HE, and the Cilo group received (Cilo 100 mg/kg/day for six weeks, oral gavage) concurrently with TAA. Cilo counteracted HE indicated in the enhancement of cognitive impairment and the motor performance of rats (P < 0.0001), modulation AMPK/SIRT1signaling pathway causing reduction of NF-kB p65 (P < 0.0001) evoked inflammation along with histopathological alterations and glial fibrillary acidic protein (GFAP) immunoreactivity (P < 0.0001), restoration nuclear factor E2-related factor 2 (Nrf2) (P < 0.0001) antioxidant effects, reduction of Bax and elevation of Bcl2 immunoreactivity (P < 0.0001) in addition to boosting mitochondrial biogenesis by upregulation of PTEN-induced kinase-1 (PINK-1)/Parkin (P < 0.0001)and restoration of Brain-derived neurotrophic factor (BDNF) (P = 0.0002)/tropomyosin-related kinase B (TrkB) (P < 0.0001)/cAMP response element-binding (CREB) (P < 0.0001) neuroprotective axis. Collectively, Cilo activates the SIRT1 trajectory to abridge mitochondrial dysfunction invigorated in the HE rat model via restoration of mitochondrial hemostasis.

Portal hypertension: recommendations for diagnosis and treatment. Consensus document sponsored by the Spanish Association for the Study of the Liver (AEEH) and the Biomedical Research Network Centre for Liver and Digestive Diseases (CIBERehd)

Portal hypertension is a hemodynamic abnormality that complicates the course of cirrhosis, as well as other diseases that affect the portal venous circulation. The development of portal hypertension compromises prognosis, especially when it rises above a certain threshold known as clinically significant portal hypertension (CSPH). In the consensus conference on Portal Hypertension promoted by the Spanish Association for the Study of the Liver and the Hepatic and Digestive diseases area of the Biomedical Research Networking Center (CIBERehd), different aspects of the diagnosis and treatment of portal hypertension caused by cirrhosis or other diseases were discussed. The outcome of this discussion was a set of recommendations that achieved varying degrees of consensus among panelists and are reflected in this consensus document. The six areas under discussion were: the relevance of CSPH and the non-invasive methods used for its diagnosis and that of cirrhosis, the prevention of the first episode of decompensation and its recurrence, the treatment of acute variceal bleeding and other complications of portal hypertension, the indications for the use of TIPS, and finally, the diagnosis and treatment of liver vascular diseases.

Portal hypertension: recommendations for diagnosis and treatment. Consensus document sponsored by the Spanish Association for the Study of the Liver (AEEH) and the Biomedical Research Network Center for Liver and Digestive Diseases (CIBERehd)

Portal hypertension is a hemodynamic abnormality that complicates the course of cirrhosis, as well as other diseases that affect the portal venous circulation. The development of portal hypertension compromises prognosis, especially when it rises above a certain threshold known as clinically significant portal hypertension (CSPH). In the consensus conference on Portal Hypertension promoted by the Spanish Association for the Study of the Liver and the Hepatic and Digestive diseases area of the Biomedical Research Networking Center (CIBERehd), different aspects of the diagnosis and treatment of portal hypertension caused by cirrhosis or other diseases were discussed. The outcome of this discussion was a set of recommendations that achieved varying degrees of consensus among panelists and are reflected in this consensus document. The six areas under discussion were: the relevance of clinically significant portal hypertension and the non-invasive methods used for its diagnosis and that of cirrhosis, the prevention of the first episode of decompensation and its recurrence, the treatment of acute variceal bleeding and other complications of portal hypertension, the indications for the use of TIPS, and finally, the diagnosis and treatment of liver vascular diseases.

Inflammation remains a dynamic component of portal hypertension in regressive alcohol-related cirrhosis

BACKGROUND

Portal hypertension (PH) resulting from static and dynamic intrahepatic changes drives liver-related complications even after removing the underlying aetiological factor.

OBJECTIVE

We investigated the impact of inflammation on the dynamic component of PH during disease regression in animal models of toxin-induced cirrhosis and patients with alcohol-related cirrhosis.

METHODS

In mice, cirrhosis was induced via toxin application for 12 weeks followed by toxin-withdrawal allowing for one or 2 weeks of regression. Furthermore, 128 patients with alcohol-related cirrhosis and alcohol abstinence undergoing same-day hepatic venous pressure gradient (HVPG) and liver stiffness measurement (LSM) were included. The influence of inflammation on the dynamic PH component was assessed using linear models. Specifically, we explored proinflammatory changes in mice/patients in whom the measured portal pressure (PP)/HVPG was significantly higher than the PP/HVPG expected from the static PH component (histological collagen proportionate area [CPA; %] in mice, LSM in patients).

RESULTS

In mice, toxin discontinuation induced a significant decrease in PP, CPA, histological hepatic inflammation and hepatic expression of proinflammatory genes (Tnfa, Il6, Cxcl1, Mcp1; all p < 0.05 for one/2 week regression vs. peak disease). Similarly, prolonged abstinence in alcohol-related cirrhosis was linked to lower HVPG/LSM and longer abstinence was correlated to lower C-reactive protein (CRP), IL-6, immunoglobulin A (IgA) and IgG levels (all p < 0.05). Nevertheless, the persistence of a low-grade proinflammatory state during regression was linked to a higher PP/HVPG than expected from static PH components. In regressive mice, higher hepatic proinflammatory gene expression (Tnfa, Il6, Il1b; all p < 0.05) was linked to higher-than-expected PP. Similarly, higher CRP, IL-6, IgA and IgG and lower complement factor C3c (all p < 0.05) were associated with higher-than-expected HVPG in abstinent patients with alcohol-related cirrhosis.

CONCLUSIONS

Although removing the underlying aetiological factor resulted in significant improvements, a persistent hepatic proinflammatory environment remained a key driver of the dynamic PH component in regressive liver disease.

CLINICAL TRIAL NUMBER

NCT03267615.

Mechanisms and implications of recompensation in cirrhosis

Decompensated cirrhosis has long been considered the irreversible end stage of liver disease, characterised by further decompensating events until death or liver transplantation. However, the observed clinical improvements after effective antiviral treatments for HBV and HCV and after sustained alcohol abstinence have changed this paradigm, leading to the concept of "recompensation" of cirrhosis. Recompensation of cirrhosis was recently defined by Baveno VII as (i) cure of the primary liver disease aetiology; (ii) disappearance of signs of decompensation (ascites, encephalopathy and portal hypertensive bleeding) off therapy; and (iii) stable improvement of liver function tests (bilirubin, international normalised ratio and albumin). Achieving these recompensation criteria is linked to a significant survival benefit. However, apart from aetiological therapies, no interventions/treatments that facilitate recompensation are available, the molecular mechanisms underlying recompensation remain incompletely understood, and early predictors of recompensation are lacking. Moreover, current recompensation criteria are based on expert opinion and may be refined in the future. Herein, we review the available evidence on cirrhosis recompensation, provide guidance on the clinical management of recompensated patients and discuss future challenges related to cirrhosis recompensation.

Endothelial Dysfunction and Liver Cirrhosis: Unraveling of a Complex Relationship

Endothelial dysfunction (ED) is the in the background of multiple metabolic diseases and a key process in liver disease progression and cirrhosis decompensation. ED affects liver sinusoidal endothelial cells (LSECs) in response to different damaging agents, causing their progressive dedifferentiation, unavoidably associated with an increase in intrahepatic resistance that leads to portal hypertension and hyperdynamic circulation with increased cardiac output and low peripheral artery resistance. These changes are driven by a continuous interplay between different hepatic cell types, invariably leading to increased reactive oxygen species (ROS) formation, increased release of pro-inflammatory cytokines and chemokines, and reduced nitric oxide (NO) bioavailability, with a subsequent loss of proper vascular tone regulation and fibrosis development. ED evaluation is often accomplished by serum markers and the flow-mediated dilation (FMD) measurement of the brachial artery to assess its NO-dependent response to shear stress, which usually decreases in ED. In the context of liver cirrhosis, the ED assessment could help understand the complex hemodynamic changes occurring in the early and late stages of the disease. However, the instauration of a hyperdynamic state and the different NO bioavailability in intrahepatic and systemic circulation-often defined as the NO paradox-must be considered confounding factors during FMD analysis. The primary purpose of this review is to describe the main features of ED and highlight the key findings of the dynamic and intriguing relationship between ED and liver disease. We will also focus on the significance of FMD evaluation in this setting, pointing out its key role as a therapeutic target in the never-ending battle against liver cirrhosis progression.

Predictive model of in-hospital mortality in liver cirrhosis patients with hyponatremia: an artificial neural network approach

Hyponatremia can worsen the outcomes of patients with liver cirrhosis. However, it remains unclear about how to predict the risk of death in cirrhotic patients with hyponatremia. Patients with liver cirrhosis and hyponatremia were screened. Eligible patients were randomly divided into the training (n = 472) and validation (n = 471) cohorts. In the training cohort, the independent predictors for in-hospital death were identified by logistic regression analyses. Odds ratios (ORs) were calculated. An artificial neural network (ANN) model was established in the training cohort. Areas under curve (AUCs) of ANN model, Child-Pugh, model for end-stage liver disease (MELD), and MELD-Na scores were calculated by receiver operating characteristic curve analyses. In multivariate logistic regression analyses, ascites (OR = 2.705, P = 0.042), total bilirubin (OR = 1.004, P = 0.003), serum creatinine (OR = 1.004, P = 0.017), and international normalized ratio (OR = 1.457, P = 0.005) were independently associated with in-hospital death. Based on the four variables, an ANN model was established. Its AUC was 0.865 and 0.810 in the training and validation cohorts, respectively, which was significantly larger than those of Child-Pugh (AUC = 0.757), MELD (AUC = 0.765), and MELD-Na (AUC = 0.769) scores. An ANN model has been developed and validated for the prediction of in-hospital death in patients with liver cirrhosis and hyponatremia.

Acute Variceal Hemorrhage in Germany-A Nationwide Study of 65,357 Hospitalized Cases: Variceal Hemorrhage in Germany

Background: Acute variceal hemorrhage (AVH) is a frequent cause of upper gastrointestinal bleeding (UGIB) in liver cirrhosis. Most cases require urgent endoscopic intervention due to potentially life-threatening courses. Different endoscopic hemostasis techniques can be used, in particular endoscopic variceal ligation (EVL) and endoscopic sclerotherapy (EST), depending on the bleeding side (esophageal, fundal, and gastric) as well as radiological interventions (e.g., embolization and transjugular intrahepatic portosystemic shunt [TIPS]). This study aimed to investigate trends in incidence, treatment modalities, and outcome parameters, such as in-hospital mortality and adverse events in Germany. Methods: We evaluated the current epidemiological trends, therapeutic strategies, and in-hospital mortality of AVH in Germany based on the standardized hospital discharge data provided by the German Federal Statistical Office from 2010 to 2019. Results: A total of 65,357 AVH cases, predominately males (68.3%), were included in the analysis. The annual incidence rate (hospitalization cases per 100,000 persons) was 8.9. The in-hospital mortality was 18.6%. The most common underlying disease was alcohol-related liver cirrhosis (60.6%). The most common clinical complication was bleeding anemia (60.1%), whereas hypovolemic shock (12.8%) was the less frequent. In esophageal variceal hemorrhage (EVH), EVL was the most frequently performed endoscopic therapy, while in gastric variceal hemorrhage (GVH), EST and fibrin glue injection were the most commonly performed therapies. EVL showed the lowest in-hospital mortality (12.3%) in EVH, while EST showed favorable results (14% in-hospital mortality) in GVH. Combination therapies overall showed a higher in-hospital mortality and were more frequent in GVH. The presence of hypovolemic shock, AKI, sepsis, artificial ventilation, ARDS, bleeding anemia, hepatic encephalopathy, and male sex was associated with a significantly worse outcome. Conclusion: Our study provides detailed insight into the incidence, patient-related risk factors, endoscopic treatment, and in-hospital mortality in a sizeable AVH collective in Germany. These data might help improve risk stratification and treatment strategies for AVH patients in the future.

Endoscopic ultrasound in portal hypertension: navigating venous hemodynamics and treatment efficacy

Portal hypertension-related complications increase mortality in patients, irrespective of its etiology. Classically, endoscopic ultrasound (EUS) was used to assess the portal venous system and collaterals, considering size and hemodynamic parameters, which correlate with portal hypertension (PH) and related complications. Furthermore, therapeutic EUS guides treatment interventions, such as embolization of the gastric varices through coil placement and tissue adhesive injection, yielding encouraging clinical results. Recently, the direct measurement of portal pressure, emerging as an alternative to hepatic venous pressure gradient, has shown promise, and further research in this area is anticipated. In this review, we aimed to provide a detailed description of various possibilities for diagnosing vascular anatomy and hemodynamics in PH and actual knowledge on the EUS usefulness for PH vessel-related complications. Also, future promises for this field of endo-hepatology are discussed.

Angiocrine signaling in sinusoidal homeostasis and liver diseases

The hepatic sinusoids are composed of liver sinusoidal endothelial cells (LSECs), which are surrounded by hepatic stellate cells (HSCs) and contain liver-resident macrophages called Kupffer cells, and other patrolling immune cells. All these cells communicate with each other and with hepatocytes to maintain sinusoidal homeostasis and a spectrum of hepatic functions under healthy conditions. Sinusoidal homeostasis is disrupted by metabolites, toxins, viruses, and other pathological factors, leading to liver injury, chronic liver diseases, and cirrhosis. Alterations in hepatic sinusoids are linked to fibrosis progression and portal hypertension. LSECs are crucial regulators of cellular crosstalk within their microenvironment via angiocrine signaling. This review discusses the mechanisms by which angiocrine signaling orchestrates sinusoidal homeostasis, as well as the development of liver diseases. Here, we summarise the crosstalk between LSECs, HSCs, hepatocytes, cholangiocytes, and immune cells in health and disease and comment on potential novel therapeutic methods for treating liver diseases.

Infectious Complications of Portal Hypertension

Patients with cirrhosis and clinically significant portal hypertension are at high risk of developing bacterial infections (BIs) that are the most common trigger of acute decompensation and acute-on-chronic liver failure. Furthermore, after decompensation, the risk of developing BIs further increases in an ominous vicious circle. BIs may be subtle, and they should be ruled out in all patients at admission and in case of deterioration. Timely administration of adequate empirical antibiotics is the cornerstone of treatment. Herein, we reviewed current evidences about pathogenesis, clinical implications and management of BIs in patients with cirrhosis and portal hypertension.

Microarray analysis demonstrates up-regulation of the endothelin-1 gene with compensatory down-regulation of the ETA receptor gene in human portal vein

High blood pressure in the portal vein, portal hypertension (PH), is the final common pathway in liver cirrhosis regardless of aetiology. Complications from PH are the major cause of morbidity and mortality in these patients. Current drug therapy to reduce portal pressure is mainly limited to β-adrenergic receptor blockade but approximately 40% of patients do not respond. Our aim was to use microarray to measure the expression of ∼20,800 genes in portal vein from patients with PH undergoing transplantation for liver cirrhosis (PH, n=12) versus healthy vessels (control, n=9) to identify potential drug targets to improve therapy. Expression of 9,964 genes above background was detected in portal vein samples. Comparing PH veins versus control (adjusted P-value < 0.05, fold change > 1.5) identified 548 up-regulated genes and 1,996 down-regulated genes. The 2,544 differentially expressed genes were subjected to pathway analysis. We identified 49 significantly enriched pathways. The endothelin pathway was ranked the tenth most significant, the only vasoconstrictive pathway to be identified. ET-1 gene (EDN1) was significantly up-regulated, consistent with elevated levels of ET-1 peptide previously measured in PH and cirrhosis. ETA receptor gene (EDNRA) was significantly down-regulated, consistent with an adaptive response to increased peptide levels in the portal vein but there was no change in the ETB gene (EDNRB). The results provide further support for evaluating the efficacy of ETA receptor antagonists as a potential therapy in addition to β-blockers in patients with PH and cirrhosis.

Update on cirrhotic cardiomyopathy: from etiopathogenesis to treatment

Cirrhotic cardiomyopathy represents a syndrome of cardiac dysfunction associated with advanced liver disease. It is the result of complex pathophysiological processes that complicate the course of the disease, and is generally associated with a poor prognosis. Pathophysiologically, portal hypertension is the key factor leading to hyperdynamic circulation, via over-activation of the neurohumoral axis. Intestinal obstruction, subclinical inflammation and hepatocellular insufficiency, with defective synthesis or metabolism of several vasoactive mediators, are essential components of this process. Since it is usually unapparent at rest and only unmasked by an inadequate cardiac response to hemodynamic stress, the diagnosis of cirrhotic cardiomyopathy is challenging and demands a multimodal approach. There is currently no specific therapy, but there are prognostically effective drugs available to treat heart failure. Therefore, it is crucial to identify patients with chronic liver disease and heart failure in order to ameliorate their outcome. This article attempts to highlight the most important aspects of cirrhotic cardiomyopathy and draws attention to this condition.

Chinese consensus on the management of liver cirrhosis

Liver cirrhosis, characterized by diffuse necrosis, insufficient regeneration of hepatocytes, angiogenesis, severe fibrosis, and the formation of pseudolobules, is a progressive, chronic liver disease induced by a variety of causes. It is clinically characterized by liver function damage and portal hypertension, and many complications may occur in its late stage. Based on the updated practice guidelines, expert consensuses, and research advances on the diagnosis and treatment of cirrhosis, the Chinese Society of Gastroenterology of Chinese Medical Association established the current consensus to standardize the clinical diagnosis and management of liver cirrhosis and guide clinical practice. This consensus contains 43 statements on the etiology, pathology and pathogenesis, clinical manifestations, major complications, diagnosis, treatment, prognosis, and chronic disease control of liver cirrhosis. Since several practice guidelines and expert consensuses on the complications of liver cirrhosis have been published, this consensus emphasizes the research progress of liver cirrhosis itself.

Obliteration of portal venules contributes to portal hypertension in biliary cirrhosis

The effects of the obliteration of portal venules (OPV) in cirrhotic portal hypertension are poorly understood. To investigate its contribution to portal hypertension in biliary cirrhosis and its underlying mechanism, we evaluated OPV using two-dimensional (2D) histopathology in liver explants from patients with biliary atresia (BA, n = 63), primary biliary cholangitis (PBC, n = 18), and hepatitis B-related cirrhosis (Hep-B-cirrhosis, n = 35). Then, three-dimensional (3D) OPV was measured by X-ray phase-contrast CT in two parallel models in rats following bile duct ligation (BDL) or carbon tetrachloride (CCl4) administration, representing biliary cirrhosis and post-necrotic cirrhosis, respectively. The portal pressure was also measured in the two models. Finally, the effects of proliferative bile ducts on OPV were investigated. We found that OPV was significantly more frequent in patients with biliary cirrhosis, including BA (78.57 ± 16.45%) and PBC (60.00 ± 17.15%), than that in Hep-B-cirrhotic patients (29.43 ± 14.94%, p < 0.001). OPV occurred earlier, evidenced by the paired liver biopsy at a Kasai procedure (KP), and was irreversible even after a successful KP in the patients with BA. OPV was also significantly more frequent in the BDL models than in the CCl4 models, as shown by 2D and 3D quantitative analysis. Portal pressure was significantly higher in the BDL model than that in the CCl4 model. With the proliferation of bile ducts, portal venules were compressed and irreversibly occluded, contributing to the earlier and higher portal pressure in biliary cirrhosis. OPV, as a pre-sinusoidal component, plays a key role in the pathogenesis of portal hypertension in biliary cirrhosis. The proliferated bile ducts and ductules gradually take up the 'territory' originally attributed to portal venules and compress the portal venules, which may lead to OPV in biliary cirrhosis. © 2024 The Pathological Society of Great Britain and Ireland.

Dibutyl phthalate (DBP) promotes Epithelial-Mesenchymal Transition (EMT) to aggravate liver fibrosis into cirrhosis and portal hypertension (PHT) via ROS/TGF-β1/Snail-1 signalling pathway in adult rats

OBJECTIVE

The primary objective of this study was to investigate the toxicological impact of Dibutyl phthalate (DBP) on the process of liver fibrosis transitioning into cirrhosis and the subsequent development of portal hypertension (PHT) through the mechanism of epithelial-mesenchymal transition (EMT) mediated by the ROS/TGF-β/Snail-1 signaling pathway.

METHOD

Carbon tetrachloride (CCl4) (1 mg/kg) was introduced in adult rats by oral feeding in CCl4 and CCl4+DBP groups twice a week for 8 weeks, and twice for another 8 week in CCl4 group. DBP was introduced by oral feeding in the CCl4+DBP group twice over the following 8 weeks. We subsequently analyzed hemodynamics measurements and liver cirrhosis degree, hepatic inflammation and liver function in the different groups. EMT related genes expression in rats in the groups of Control, DBP, CCl4 and CCl4+DBP were measured by immunohistochemistry (IHC). Enzyme-linked immunosorbent Assay (ELISA), qRT-PCR, western blot were used to detect the EMT related proteins and mRNA gene expression levels in rats and primary hepatocytes (PHCs). Reactive oxygen species (ROS) were examined with a ROS detection kit.

RESULTS

The results showed that the CCl4+DBP group had higher portal pressure (PP) and lower mean arterial pressure (MAP) than the other groups. Elevated collagen deposition, profibrotic factor, inflammation, EMT levels were detected in DBP and CCl4+DBP groups. ROS, TGF-β1 and Snail-1 were highly expressed after DBP exposure in vitro. TGF-β1 had the potential to regulate Snail-1, and both of them were subject to regulation by ROS.

CONCLUSION

DBP could influence the progression of EMT through its toxicological effect by ROS/TGF-β1/Snail-1 signalling pathway, causing cirrhosis and PHT in final. The findings of this research might contribute to a novel comprehension of the underlying toxicological mechanisms and animal model involved in the progression of cirrhosis and PHT, and potentially offered a promising therapeutic target for the treatment of the disease.

Management of Portal Hypertension in Patients with Hepatocellular Carcinoma on Systemic Treatment: Current Evidence and Future Perspectives

The management of CSPH in patients undergoing systemic treatment for HCC has emerged as a critical concern due to the absence of reliable diagnostic criteria and uncertainties surrounding therapeutic approaches. This review aims to underscore the primary pathophysiological aspects linking HCC and PH, while also addressing the current and emerging clinical strategies for the management of portal hypertension. A review of studies from January 2003 to June 2023 was conducted using the PubMed database and employing MeSH terms, such as "hepatocellular carcinoma", "immune checkpoint inhibitors", "systemic therapy", "portal hypertension", "variceal bleeding" and "tyrosine kinase inhibitors". Despite promising results of tyrosine kinase inhibitors in animal models for PH and fibrosis, only Sorafenib has demonstrated similar effects in human studies, whereas Lenvatinib appears to promote PH development. The impact of Atezolizumab/Bevacizumab on PH remains uncertain, with an increasing risk of bleeding related to Bevacizumab in patients with prior variceal hemorrhage. Given the absence of specific guidelines, endoscopic surveillance during treatment is advisable, and primary and secondary prophylaxis of variceal bleeding should adhere to the Baveno VII recommendations. Furthermore, in patients with advanced HCC, refinement of diagnostic criteria for CSPH and guidelines for its surveillance are warranted.

Liver sinusoidal endothelial cells as potential drivers of liver fibrosis (Review)

Liver fibrosis due to viral or metabolic chronic liver diseases is a major challenge of global health. It is a critical pre‑stage condition of severe hepatopathy, characterized by excessive accumulation of extracellular matrix components and ongoing chronic inflammation. To date, early prevention of liver fibrosis remains challenging. As the most abundant non‑parenchymal hepatic cell population, liver sinusoidal endothelial cells (LSECs) are stabilizers that maintain the intrahepatic environment. Notably, LSECs dysfunction appears to be implicated in the progression of liver fibrosis via numerous mechanisms. Following sustained liver injury, they lose their fenestrae (cytoplasmic pores) and change their crosstalk with other cellular interactions in the hepatic blood environment. LSEC‑targeted therapy has shown promising effects on fibrosis resolution, opening up new opportunities for anti‑fibrotic therapy. In light of this, the present study summarized changes in LSECs during liver fibrosis and their interactions with hepatic milieu, as well as possible therapeutic approaches that specially target LSECs.

The polymorphic variant of SerpinB3 (SerpinB3-PD) is associated with faster cirrhosis decompensation

BACKGROUND

SerpinB3 is a cysteine protease inhibitor involved in liver disease progression due to its proinflammatory and profibrogenic properties. The polymorphic variant SerpinB3-PD (SB3-PD), presents a substitution in its reactive centre loop, determining the gain of function.

AIMS

To disclose the clinical characteristics of a cohort of patients with cirrhosis in relation to the presence of SB3-PD and to assess the effect of this genetic variant on fibrogenic and inflammatory cytokines in vitro.

METHODS

We assessed SB3 polymorphism in 90 patients with cirrhosis, prospectively followed up in our referral centre. We used HepG2 and HuH-7 cells transfected to overexpress either wild-type SB3 (SB3-WT) or SB3-PD to assess their endogenous effect, while LX2 and THP-1 cells were treated with exogenous SB3-WT or SB3-PD proteins.

RESULTS

Patients carrying SB3-PD had more severe portal hypertension and higher MELD scores, than patients carrying SB3-WT. In multivariate analysis, SB3-PD was an independent predictor of cirrhosis complications. Patients with SB3-PD polymorphism presented with more severe liver fibrosis and inflammatory features. Hepatoma cells overexpressing SB3-PD showed higher TGF-β1 expression than controls. The addition of recombinant SB3-PD induced an up-regulation of TGF-β1 in LX2 cells and a more prominent inflammatory profile in THP-1 cells, compared to the effect of SB3-WT protein.

CONCLUSIONS

The polymorphic variant SB3-PD is highly effective in determining activation of TGF-β1 and inflammation in vitro. Patients with cirrhosis who carry SB3-PD polymorphism may be more prone to develop severe liver disease progression. However, further validation studies are warranted to support the in vivo relevance of this polymorphism.

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.

Liver cirrhosis and complications from the perspective of dysbiosis

The gut-liver axis refers to the intimate relationship and rigorous interaction between the gut and the liver. The intestinal barrier's integrity is critical for maintaining liver homeostasis. The liver operates as a second firewall in this interaction, limiting the movement of potentially dangerous compounds from the gut and, as a result, contributing in barrier management. An increasing amount of evidence shows that increased intestinal permeability and subsequent bacterial translocation play a role in liver damage development. The major pathogenic causes in cirrhotic individuals include poor intestinal permeability, nutrition, and intestinal flora dysbiosis. Portal hypertension promotes intestinal permeability and bacterial translocation in advanced liver disease, increasing liver damage. Bacterial dysbiosis is closely related to the development of cirrhosis and its related complications. This article describes the potential mechanisms of dysbiosis in liver cirrhosis and related complications, such as spontaneous bacterial peritonitis, hepatorenal syndrome, portal vein thrombosis, hepatic encephalopathy, and hepatocellular carcinoma, using dysbiosis of the intestinal flora as an entry point.

Recent Advances in the Pathogenesis and Clinical Evaluation of Portal Hypertension in Chronic Liver Disease

In chronic liver disease, hepatic stellate cell activation and degeneration of liver sinusoidal endothelial cells lead to structural changes, which are secondary to fibrosis and the presence of regenerative nodules in the sinusoids, and to functional changes, which are related to vasoconstriction. The combination of such changes increases intrahepatic vascular resistance and causes portal hypertension. The subsequent increase in splanchnic and systemic hyperdynamic circulation further increases the portal blood flow, thereby exacerbating portal hypertension. In clinical practice, the hepatic venous pressure gradient is the gold-standard measure of portal hypertension; a value of ≥10 mm Hg is defined as clinically significant portal hypertension, which is severe and is associated with the risk of liver-related events. Hepatic venous pressure gradient measurement is somewhat invasive, so evidence on the utility of risk stratification by elastography and serum biomarkers is needed. The various stages of cirrhosis are associated with different outcomes. In viral hepatitis-related cirrhosis, viral suppression or elimination by nucleos(t)ide analog or direct-acting antivirals results in recompensation of liver function and portal pressure. However, careful follow-up should be continued, because some cases have residual clinically significant portal hypertension even after achieving sustained virologic response. In this study, we reviewed the current and future prospects for portal hypertension.

Pre-emptive transjugular intrahepatic portosystemic shunt in pediatric cystic fibrosis-related liver disease and portal hypertension: prospective long-term results

PURPOSE

Portal hypertension (PHT) and its sequelae are the most clinically important manifestations in cystic fibrosis-related liver disease (CFLD). This paper aimed to evaluate the safety and efficacy of a pre-emptive transjugular intrahepatic portosystemic shunt (TIPS) to prevent PHT-related complications in pediatric patients with CFLD.

METHODS

This was a prospective single-arm study on pediatric patients with CFLD, signs of PHT, and preserved liver function who underwent a pre-emptive TIPS in a single tertiary CF center between 2007 and 2012. The long-term safety and clinical efficacy were assessed.

RESULTS

A pre-emptive TIPS was performed on seven patients with a mean age of 9.2 years (± standard deviation: 2.2). The procedure was technically successful in all patients, with an estimated median primary patency of 10.7 years [interquartile range (IQR) 0.5-10.7)]. No variceal bleeding was observed during the median follow-up of 9 years (IQR 8.1-12.9). In two patients with advanced PHT and rapidly progressive liver disease, severe thrombocytopenia could not be stopped. Subsequent liver transplantation revealed biliary cirrhosis in both patients. In the remaining patients with early PHT and milder porto-sinusoidal vascular disease, symptomatic hypersplenism did not occur, and liver function remained stable until the end of the follow-up. Inclusion for pre-emptive TIPS was discontinued in 2013 following an episode of severe hepatic encephalopathy.

CONCLUSION

TIPS is a feasible treatment with encouraging long-term primary patency to avoid variceal bleeding in selected patients with CF and PHT. However, as the progression of liver fibrosis, thrombocytopenia, and splenomegaly is inevitable, the clinical benefits due to pre-emptive placement appear to be minor.

Adrenoceptors and Hypertension

Hypertension is a very prevalent condition associated with high mortality and morbidity, secondary to changes resulting in blood vessels and resultant end-organ damage. Haemodynamic changes, including an initial rise in cardiac output followed by an increase in total peripheral resistance, denote the early changes associated with borderline or stage 1 hypertension, especially in young men. Increased sodium reabsorption leading to kidney damage is another mechanism proposed as one of the initial triggers for essential hypertension. The underlying pathophysiological mechanisms include catecholamine-induced α1- and ß1-adrenoceptor stimulation, and renin-angiotensin-aldosterone system activation leading to endothelial dysfunction which is believed to lead to persistent blood pressure elevation.α1 blockers, α2 agonists, and ß blockers were among the first oral anti-hypertensives. They are no longer first-line therapy after outcome trials did not demonstrate any benefits over and above other agents, despite similar blood pressure reductions. Angiotensin-converting enzyme inhibitors (or angiotensin receptor blockers), calcium channel blockers, and thiazide-like diuretics are now considered the first line of therapy, although adrenoceptor agents still have a role as second- or third-line therapy. The chapter also highlights hypertension in specific medical conditions such as pregnancy, phaeochromocytoma, hyperthyroidism, portal hypertension, pulmonary arterial hypertension, and ocular hypertension, to provide an overview for clinicians and researchers interested in the role of adrenoceptors in the pathophysiology and management of hypertension.

Von Willebrand factor processing in patients with advanced chronic liver disease and its relation to portal hypertension and clinical outcome

BACKGROUND AND AIMS

Endothelial dysfunction and portal hypertension (PH) are reflected by increased von Willebrand factor antigen (VWF-Ag) levels in advanced chronic liver disease (ACLD). This study investigated VWF release and cleavage and their association with PH and clinical outcomes.

METHODS

Levels of VWF-Ag, VWF-N (VWF-propeptide), and VWF-A (VWF processed by the main VWF-cleaving protease ADAMTS13) were assessed in 229 patients with clinically stable ACLD (hepatic venous pressure gradient [HVPG] ≥ 6 mmHg; absence of bacterial infections or acute decompensation) undergoing HVPG-measurement. Liver-healthy individuals served as controls (n = 24).

RESULTS

VWF-Ag and VWF-N were similarly accurate for the identification of clinically significant PH (CSPH; HVPG ≥ 10 mmHg) in compensated ACLD (AUROC: VWF-Ag 0.748; VWF-N 0.728). ADAMTS13 activity was similar between patients with ACLD and controls and did not correlate with PH and disease severity, whereas VWF cleavage decreased in patients with CSPH (i.e., VWF-Ag/-A-ratio increased). In vitro VWF activity strongly reflected VWF-Ag levels (Spearman's r = 0.874, p < 0.001), but decreased (vs. controls) in patients with CSPH when normalized to VWF-Ag levels (VWF-activity/-Ag-ratio). VWF-Act/-Ag ratio correlated negatively with ADAMTS13 activity (r =- 0.256, p < 0.001). ADAMTS13 activity was independently predictive for (i) portal vein thrombosis (PVT) and (ii) hepatic decompensation or liver-related death.

CONCLUSIONS

VWF-Ag levels and its propeptide are similarly suitable surrogates of PH in patients with compensated ACLD. ADAMTS13-Act was not linked to disease and PH severity, however, when normalized to VWF-Ag, both VWF cleavage and VWF activity were decreased in patients with CSPH, as compared to liver-healthy individuals. Low ADAMTS13-Act was associated with presumably more procoagulant VWF and adverse outcomes.

CLINICAL TRIAL NUMBER

NCT03267615.

The genetics of portal hypertension: Recent developments and the road ahead

Portal hypertension (PH), defined as a pathological increase in the portal vein pressure, has different aetiologies and causes. Intrahepatic PH is mostly secondary to the presence of underlying liver disease leading to cirrhosis, characterized by parenchymal changes with deregulated accumulation of extracellular matrix and vascular abnormalities; liver sinusoidal endothelial cells and hepatic stellate cells are key players in PH progression, able to influence each other. However, PH may also develop independently of parenchymal damage, as occur in portosinusoidal vascular disorder (PSVD), a group of clinical and histological entities characterized by portal vasculature dysfunctions. In this particular group of disorders, the pathophysiology of PH is still poorly understood. In the last years, several genetic studies, based on genome-wide association studies or whole-exome sequencing analysis, have highlighted the importance of genetic heritability in PH pathogenesis, both in cirrhotic and non-cirrhotic cases. The common PNPLA3 p.I148M variant, one of the main determinants of the susceptibility to steatotic liver disease, has also been associated with decompensation in patients with PH. Genetic variations at loci influencing coagulation, mainly the ABO locus, may directly contribute to the pathogenesis of PH. Rare genetic variants have been associated with familiar cases of progressive PSVD. In this review, we summarize the recent knowledges on genetic variants predisposing to PH development, contributing to better understand the role of genetic factors in PH pathogenesis.

5-MTHF enhances the portal pressure reduction achieved with propranolol in patients with cirrhosis: A randomized placebo-controlled trial

BACKGROUND & AIMS

β-blockers reduce hepatic venous pressure gradient (HVPG) by decreasing portal inflow, with no reduction in intrahepatic vascular resistance. 5-Methyltetrahydrofolate (5-MTHF) can prevent oxidative loss of tetrahydrobiopterin (BH4), a cofactor for endothelial nitric oxide synthase coupling. It also converts homocysteine (tHcy) into methionine and enables the degradation of asymmetric dimethylarginine (ADMA), an inhibitor of endothelial nitric oxide synthase. The aim of this study was to evaluate the effects of 5-MTHF in combination with propranolol on HVPG and nitric oxide bioavailability markers in patients with cirrhosis and portal hypertension.

METHOD

Sixty patients with cirrhosis and HVPG ≥12 mmHg were randomized 1:1 to receive treatment with 5-MTHF+propranolol or placebo+propranolol for 90 days under double-blind conditions. HVPG and markers of nitric oxide bioavailability (BH4, ADMA and tHcy) were measured again at the end of treatment.

RESULTS

Groups were similar in terms of baseline clinical and hemodynamic data and nitric oxide bioavailability markers. HVPG decreased in both groups, but the magnitude of the change was significantly greater in the group treated with 5-MTHF+propranolol compared to placebo+propranolol (percentage decrease, 20 [29-9] vs. 12.5 [22-0], p = 0.028), without differences in hepatic blood flow. At the end of treatment, 5-MTHF+propranolol (vs. placebo+propranolol) was associated with higher BH4 (1,101.4 ± 1,413.3 vs. 517.1 ± 242.8 pg/ml, p <0.001), lower ADMA (109.3 ± 52.7 vs. 139.9 ± 46.7 μmol/L, p = 0.027) and lower tHcy (μmol/L, 11.0 ± 4.6 vs. 15.4 ± 7.2 μmol/L, p = 0.010) plasma levels.

CONCLUSION

In patients with cirrhosis and portal hypertension, 5-MTHF administration significantly enhanced the HVPG reduction achieved with propranolol. This effect appears to be mediated by improved nitric oxide bioavailability in the hepatic microcirculation.

CLINICAL TRIAL EUDRACT NUMBER

2014-002018-21.

IMPACT AND IMPLICATIONS

Currently, the pharmacological prevention of cirrhosis complications due to portal hypertension, such as esophageal varices rupture, is based on the use of β-blockers, but some patients still present with acute variceal bleeding, mainly due to an insufficient reduction of portal pressure. In this study, we sought to demonstrate that the addition of folic acid to β-blockers is more effective in reducing portal pressure than β-blockers alone. This finding could represent the basis for validation studies in larger cohorts, which could impact the future prophylactic management of variceal bleeding in cirrhosis. Enhancing the benefit of β-blockers with a safe, accessible, cost-effective drug could improve clinical outcomes in cirrhosis, which in turn could translate into a reduction in the rates and costs of hospitalization, and ultimately into improved survival.

Presence of NOD2 mutations is not associated with hepatic or systemic hemodynamic abnormalities of cirrhosis

BACKGROUND

Patients with cirrhosis who carry NOD2 mutations are susceptible to bacterial infections. The aim was to evaluate the association of NOD2 mutations with hepatic and systemic hemodynamics in cirrhosis.

PATIENTS AND METHODS

This is a secondary analysis of a prospectively collected database in the context of the screening for the INCA trial (EudraCT 2013-001626-26). This cross-sectional study compared hemodynamic findings according to NOD2 status in 215 patients. Patients were genotyped for NOD2 variants (p.N289S, p.R702W, p.G908R, c.3020insC, rs72796367). Hepatic hemodynamic study and right heart catheterization were performed.

RESULTS

Patients had a median age of 59 (IQR 53-66) years, and 144 (67%) were men. Most patients (64%) were Child-Pugh stage B. Sixty-six patients (31%) carried a NOD2 mutation, which was slightly more common among Child-Pugh stage C (p = 0.05), without differences in MELD [wild-type: 13 (10-16); NOD2 variants 13 (10-18)]. No differences in hepatic and systemic hemodynamics were observed according to NOD2 status. If excluding patients on prophylactic or therapeutic antibiotics, again no association between hepatic or systemic hemodynamics and NOD2 status could be observed.

CONCLUSION

NOD2 mutations are not associated with hepatic or systemic hemodynamic abnormalities in patients with decompensated cirrhosis, suggesting that other mechanisms leading to bacterial translocation predominate.

A model for predicting poor survival in patients with cirrhosis undergoing portosystemic shunt embolization

BACKGROUND AND AIM

Portosystemic shunt embolization (PSSE) is a promising treatment for hepatic encephalopathy (HEP) and gastric varix (GV) in cirrhotic patients with a spontaneous portosystemic shunt. However, PSSE may worsen portal hypertension causing hepatorenal syndrome, liver failure, and mortality. This study aimed to develop and validate a prognostic model that helps identify patients with a risk of poor short-term survival after PSSE.

METHODS

We included 188 patients who underwent PSSE for recurrent HEP or GV at a tertiary center in Korea. To develop a prediction model for 6-month survival after PSSE, Cox proportional-hazard model was used. The developed model was validated in a separate cohort of 184 patients from two other tertiary centers.

RESULTS

In multivariable analysis, the 1-year overall survival after PSSE was significantly associated with baseline levels of serum albumin, total bilirubin, and international normalized ratio (INR). We therefore developed the albumin-bilirubin-INR (ABI) score by assigning 1 point each for albumin < 3.0 g/dL, total bilirubin ≥ 1.5 mg/dL, and INR ≥ 1.5. Time-dependent areas under the curve of the ABI score for predicting 3-month and 6-month survival were 0.85 and 0.85 in the development cohort and 0.83 and 0.78 in the validation cohort, indicating good discrimination performance. The ABI score showed a better discrimination and calibration performance than the model for end-stage liver disease and the Child-Pugh scores, especially in high-risk patients.

CONCLUSIONS

The ABI score is a simple prognostic model that helps decide whether to proceed with PSSE for the prevention of HEP or GV bleeding in patients with spontaneous portosystemic shunt.

Synergistic Modulation of a Tunable Microenvironment to Fabricate a Liver Fibrosis Chip for Drug Testing

Liver fibrosis is a progressive physiological change that occurs after liver injury and seriously endangers human health. The lack of reliable and physiologically relevant pathological models of liver fibrosis leads to a longer drug development period and sizeable economic investment. The fabrication of a biomimetic liver-on-a-chip is significant for liver disease treatment and drug development. Here, a sandwich chip with a microwell array structure in its bottom layer was fabricated to simulate the Disse space structure of hepatic sinusoids in vitro. By synergistic modulation of the cross-linking degree of gelatin-methacryloyl (GelMA) hydrogels and the induction of transforming growth factor-beta (TGF-β), the early and late stages of liver fibrosis were designed in the chip. Owing to its three-dimensional-mixed-culture strategy, it was possible to construct a liver sinusoid model in vitro to allow for faithful physiological emulation. The model was further subjected to drug treatment, and it presented a significant difference in treatment response in early and late fibrosis progression. Our system provides a unique method for emulating liver function through a vitro liver fibrosis-on-a-chip, potentially paving the way for investigating human liver fibrosis and related drug development.

Molecular Mechanisms Underlying Vascular Liver Diseases: Focus on Thrombosis

Vascular liver disorders (VLDs) comprise a wide spectrum of clinical-pathological entities that primarily affect the hepatic vascular system of both cirrhotic and non-cirrhotic patients. VLDs more frequently involve the portal and the hepatic veins, as well as liver sinusoids, resulting in an imbalance of liver homeostasis with serious consequences, such as the development of portal hypertension and liver fibrosis. Surprisingly, many VLDs are characterized by a prothrombotic phenotype. The molecular mechanisms that cause thrombosis in VLD are only partially explained by the alteration in the Virchow's triad (hypercoagulability, blood stasis, and endothelial damage) and nowadays their pathogenesis is incompletely described and understood. Studies about this topic have been hampered by the low incidence of VLDs in the general population and by the absence of suitable animal models. Recently, the role of coagulation imbalance in liver disease has been postulated as one of the main mechanisms linked to fibrogenesis, so a novel interest in vascular alterations of the liver has been renewed. This review provides a detailed analysis of the current knowledge of molecular mechanisms of VLD. We also focus on the promising role of anticoagulation as a strategy to prevent liver complications and to improve the outcome of these patients.

Angiocrine Signaling in Sinusoidal Health and Disease

Liver sinusoidal endothelial cells (LSECs) are key players in maintaining hepatic homeostasis. They also play crucial roles during liver injury by communicating with liver cell types as well as immune cells and promoting portal hypertension, fibrosis, and inflammation. Cutting-edge technology, such as single cell and spatial transcriptomics, have revealed the existence of distinct LSEC subpopulations with a clear zonation in the liver. The signals released by LSECs are commonly called "angiocrine signaling." In this review, we summarize the role of angiocrine signaling in health and disease, including zonation in healthy liver, regeneration, fibrosis, portal hypertension, nonalcoholic fatty liver disease, alcohol-associated liver disease, aging, drug-induced liver injury, and ischemia/reperfusion, as well as potential therapeutic advances. In conclusion, sinusoidal endotheliopathy is recognized in liver disease and promising preclinical studies are paving the path toward LSEC-specific pharmacotherapies.

Close Relationship between Systemic Arterial and Portal Venous Pressure in an Animal Model with Healthy Liver

It is unclear to what extent systemic arterial blood pressure influences portal pressure. This relationship is clinically important as drugs, which are conventionally used for therapy of portal hypertension, may also influence systemic arterial blood pressure. This study investigated the potential correlation between mean arterial (MAP) and portal venous pressure (PVP) in rats with healthy livers. In a rat model with healthy livers, we investigated the effect of manipulation of MAP on PVP. Interventions consisted of 0.9% NaCl (group 1), 0.1 mg/kg body weight (bw) Sildenafil (low dose), an inhibitor of phosphodiesterase-5 (group 2), and 1.0 mg/kg bw Sildenafil (high dose, group 3) in 600 µL saline injected intravenously. Norepinephrine was used to increase MAP in animals with circulatory failure while PVP was monitored. Injection of the fluids induced a transient drop in MAP and PVP, probably due to a reversible cardiac decompensation. The drop in MAP and drop in PVP are significantly correlated. The time lag between change in MAP and change in PVP by 24 s in all groups suggests a cause-and-effect relationship. Ten minutes after the injection of the fluid, cardiac function was normalized. Thereafter, MAP gradually decreased. In the NaCl group, PVP decreases by 0.485% for a 1% drop of MAP, by 0.550% in the low-dose sildenafil group, and by 0.651% in the high-dose sildenafil group (p < 0.05 for difference group two vs. group one, group three vs. group one, and group three vs. group two). These data suggest that Sildenafil has an inherent effect on portal pressure that exceeds the effect of MAP. Injection of norepinephrine led to a sudden increase in MAP followed by an increase in PVP after a time lag. These data show a close relationship between portal venous pressure and systemic arterial pressure in this animal model with healthy livers. A change in MAP is consequently followed by a change in PVP after a distinct time lag. This study, furthermore, suggests that Sildenafil influences portal pressure. Further studies should be performed in a model with cirrhotic livers, as these may be important in the evaluation of vasoactive drugs (e.g., PDE-5-inhibitors) for therapy of portal hypertension.

Hepatic and portal vein Doppler ultrasounds in assessing liver inflammation and fibrosis in chronic HBV infection with a normal ALT level

Aims

To discuss the clinical value of hepatic and portal vein Doppler ultrasounds in assessing liver inflammation and fibrosis in patients with chronic hepatitis B virus (HBV) infection, and a normal alanine transaminase (ALT) level.

Methods

94 patients with chronic HBV infections who had undergone ultrasound-guided liver biopsies were enrolled and grouped by the liver tissue pathological results. Analyzed the differences and correlation between parameters of the hepatic and portal vein Doppler ultrasounds are discussed across different degrees of liver inflammation and fibrosis.

Results

There were 27 patients with no significant liver damage and 67 patients with significant liver damage, there were significant differences in the parameters of the hepatic and portal vein Doppler ultrasounds between them (p < 0.05). As liver inflammation was aggravated, the inner diameter of the portal vein increased, and the blood flow velocities of the portal and superior mesenteric veins decreased (p < 0.05). When liver fibrosis became more severe, the inner diameter of the portal vein increased, while the blood flow velocities of the portal, superior mesenteric, and splenic veins decreased, and the Doppler waveforms of hepatic veins became unidirectional or flat (p < 0.05). The receiver operating characteristic (ROC) curve showed the assessment efficacy of hepatic and portal vein Doppler ultrasounds was superior to abdominal Doppler ultrasound alone in assessing liver fibrosis, and the combination of the two examination techniques outperformed any technique used alone.

Conclusion

The hepatic and portal vein Doppler ultrasounds have important clinical value for assessing liver fibrosis in patients with chronic HBV infection, to aid improve the diagnosis of liver fibrosis.

The Impact of Partial Splenic Embolization on Portal Hypertensive Gastropathy in Cirrhotic Patients with Portal Hypertension

This study investigated the impact of partial splenic embolization (PSE) on portal hypertensive gastropathy (PHG). We retrospectively analyzed endoscopic findings and the portal venous system of 31 cirrhotic patients with PHG. The improved group was defined as the amelioration of PHG findings using the McCormack classification. Child–Pugh scores of the improved group (18 of 31 patients) were significantly lower compared with those of the non-improved group (p = 0.018). The changes in the diameters of the portal trunk and those of the spleno-portal junction and spleen hilum in the splenic vein of the improved group were significantly larger than those of the non-improved group (p = 0.007, p = 0.025, and p = 0.003, respectively). The changes in the diameters of the portal vein and splenic hilum of the splenic vein showed significant correlations with Child–Pugh score (r = 0.386, p = 0.039; r = 0.510, p = 0.004). In a multivariate analysis of baseline factors related to the improved group, Child–Pugh grade A was significantly associated with the improvement of PHG (odds ratio 6.875, p = 0.033). PSE could be useful for PHG, especially in patients with Child–Pugh grade A, at least in the short term.

DLL4-Notch signalling in acute-on-chronic liver failure: State of the art and perspectives

Acute-on-chronic liver failure (ACLF) is a syndrome characterized by acute decompensation of chronic liver disease associated with multiple-organ failures and high short-term mortality. Acute insults to patients with chronic liver disease can lead to ACLF, among which, hepatitis B virus-related ACLF is the most common type of liver failure in the Asia-Pacific region. Currently, immune-metabolism disorders and systemic inflammation are proposed to be the main mechanisms of ACLF. The resulting cholestasis and intrahepatic microcirculatory dysfunction accelerate the development of ACLF. Treatments targeting immune regulation, metabolic balance, microcirculation maintenance and bile duct repair can alleviate inflammation and restore the tissue structure. An increasing number of studies have demonstrated that delta-like ligand 4 (DLL4), one of the Notch signalling ligands, plays a vital role in immune regulation, metabolism, angiogenesis, and biliary regeneration, which participate in liver pathological and physiological processes. The detailed mechanism of the DLL4-Notch signalling pathway in ACLF has rarely been investigated. Here, we review the evidence showing that DLL4-Notch signalling is involved in ACLF and analyse the potential role of DLL4 in the treatment of ACLF.

MELD-Lactate Predicts Poor Outcome in Variceal Bleeding in Cirrhosis

BACKGROUND

Predictors of poor outcome associated with variceal bleeding remain suboptimal. In patients with cirrhosis, serum lactate combined with Model for End-Stage Liver Disease (MELD-LA) improved prediction across heterogeneous populations. However, prognostic properties have not yet been assessed in the context of variceal bleeding.

AIMS

We aimed to evaluate the predictive performance of MELD-LA compared to MELD, lactate, and nadir hemoglobin in cirrhosis patients with variceal bleeding.

METHODS

In this multicenter study, we identified 472 patients with variceal bleeding from a German primary cohort (University Hospitals Hamburg/Frankfurt/Cologne), and two independent external validation cohorts [Veterans Affairs (VA), Baylor University]. Discrimination for 30-day mortality was analyzed and scores were compared. MELD-LA was evaluated separately in validation cohorts to ensure consistency of findings.

RESULTS

In contrast to nadir hemoglobin, MELD and peak-lactate at time of bleeding were significantly higher in 30-day non-survivors in the primary cohort (p = 0.708; p < 0.001). MELD-LA had excellent discrimination for 30-day mortality (AUROC 0.82, 95% CI 0.76-0.88), better than MELD and peak-lactate (AUROC 0.78, 95% CI 0.71-0.84; AUROC 0.73, 95% CI 0.66-0.81). MELD-LA predicted 30-day mortality independently of age, sex, severity of liver disease and vasopressor support (HR 1.29 per 1-point-increase of MELD-LA; 95% CI 1.19-1.41; p < 0.001). Similarly, MELD-LA demonstrated excellent discrimination for 30-day mortality in the VA (AUROC = 0.86, 95% CI 0.79-0.93) and Baylor cohort (AUROC = 0.85, 95% CI 0.74-0.95).

CONCLUSIONS

MELD-LA significantly improves discrimination of short-term mortality associated with variceal bleeding, compared to MELD, peak-lactate and nadir hemoglobin. Thus, MELD-LA might represent a useful and objective marker for risk assessment and therapeutic intervention in patients with variceal bleeding.

Cirrhosis and non-hepatic surgery in 2023 - a precision medicine approach

INTRODUCTION

Patients with liver disease and portal hypertension frequently require surgery carrying high morbidity and mortality. Accurately estimating surgical risk remains challenging despite improved medical and surgical management.

AREAS COVERED

This review aims to outline a comprehensive approach to preoperative assessment, appraise methods used to predict surgical risk, and provide an up-to-date overview of outcomes for patients with cirrhosis undergoing non-hepatic surgery.

EXPERT OPINION

Robust preoperative, individually tailored, and precise risk assessment can reduce peri- and postoperative complications in patients with cirrhosis. Established prognostic scores aid stratification, providing an estimation of postoperative mortality, albeit with limitations. VOCAL-Penn Risk Score may provide greater precision than established liver severity scores. Amelioration of portal hypertension in advance of surgery may be considered, with prospective data demonstrating hepatic venous pressure gradient as a promising surrogate marker of postoperative outcomes. Morbidity and mortality vary between types of surgery with further studies required in patients with more advanced liver disease. Patient-specific considerations and practicing precision medicine may allow for improved postoperative outcomes.

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.

The Role of the Spleen in Portal Hypertension

As liver disease progresses, intrahepatic vascular resistance increases (backward flow theory of portal hypertension) and collateral veins develop. Adequate portal hypertension is required to maintain portal flow into the liver through an increase in blood flow into the portal venous system (forward flow theory of portal hypertension). The splenic artery resistance index is significantly and selectively elevated in cirrhotic patients. In portal hypertension, a local hyperdynamic state occurs around the spleen. Splenomegaly is associated with a poor prognosis in cirrhosis and is caused by spleen congestion and by enlargement and hyperactivation of splenic lymphoid tissue. Hypersplenism can lead to thrombocytopenia caused by increased sequestering and breakdown of platelets in the spleen. The close relationship between the spleen and liver is reflected in the concept of the hepatosplenic axis. The spleen is a regulatory organ that maintains portal flow into the liver and is the key organ in the forward flow theory of portal hypertension. This review summarizes the literature on the role of the spleen in portal hypertension.

[Current diagnostics and treatment of portal hypertension]

In industrial nations portal hypertension is mostly a consequence of liver cirrhosis and is a prerequisite for complications, such as esophageal varices and ascites. The pathophysiology of portal hypertension is complex. It is defined as an increase in the hepatovenous pressure gradient to > 5 mm Hg, with complications to be expected at ≥ 10 mm Hg. Measurement of the pressure of the hepatic vein occlusion is the gold standard for estimating portal pressure but this is not very practical. Liver elastography, in particular, has proven to be an effective noninvasive tool to identify patients with clinically significant portal hypertension (CSPH). Current treatment concepts address the CSPH even before the onset of complications to reduce the likelihood of decompensation. In addition to beta blockers, a transjugular intrahepatic portosystemic shunt is the most important procedure to lower portal vein pressure and enables an improvement in the prognosis of selected patients.

Systemic inflammation is linked to liver fibrogenesis in patients with advanced chronic liver disease

BACKGROUND & AIMS

Experimental evidence indicates that systemic inflammation (SI) promotes liver fibrogenesis. This study investigated the potential link between SI and fibrogenesis in patients with advanced chronic liver disease (ACLD).

METHODS

Serum biomarkers of SI (CRP, IL-6, procalcitonin [PCT]) and extracellular matrix (ECM) turnover (i.e., fibrogenesis/fibrolysis) were analysed in 215 prospectively recruited patients with ACLD (hepatic venous pressure gradient [HVPG] ≥6 mm Hg) undergoing hepatic vein catheterization. Patients with non-elective hospitalization or bacterial infection were excluded. Histological alpha-smooth muscle actin (α-SMA) area was quantified on full biopsy scans by automated morphometric quantification in a subset of 34 patients who underwent concomitant transjugular liver biopsy.

RESULTS

Histological α-SMA proportionate area correlated with enhanced liver fibrosis (ELF) score (Spearman's ρ = 0.660, p < .001), markers of collagen formation (PRO-C3, ρ = 0.717, p < .001; PRO-C6, ρ = 0.526, p = .002) and tissue inhibitor of metalloproteinases-1 (TIMP1; ρ = 0.547, p < .001), indicating that these blood biomarkers are capable of reflecting the dynamic process of ECM turnover. CRP, IL-6 and PCT levels correlated with ELF, biomarkers of collagen synthesis/degradation and TIMP1, both in compensated and decompensated patients. Multivariate linear regression models (adjusted for HVPG) confirmed that CRP, IL-6 and PCT were independently linked to markers of liver fibrogenesis and ECM turnover.

CONCLUSION

Systemic inflammation is linked to both liver fibrogenesis and ECM turnover in ACLD and this association is not confounded by the severity of liver disease, as evaluated by HVPG. Our study confirms experimental data on the detrimental impact of SI on ECM deposition and fibrosis progression in a thoroughly characterized cohort of patients with ACLD.

The role of microRNAs on the pathogenesis, diagnosis and management of portal hypertension in patients with chronic liver disease

INTRODUCTION

Portal hypertension (PH) is the elevated pressure in the portal vein, which results in poor functioning of the liver and is influenced by various factors like liver cirrhosis, nonalcoholic fatty liver disease, schistosomiasis, thrombosis, and angiogenesis. Though the diagnosis and treatment have been advanced, early diagnosis of the disease remains a challenge, and the diagnosis methods are often invasive. Hence, the clear understanding of the molecular mechanisms of PH can give rise to the development of novel biomarkers which can pave way for early diagnosis in noninvasive methods, and also the identification of target genes can elucidate an efficient therapeutic target.

AREAS COVERED

PubMed and Embase database was used to search articles with search terms 'Portal Hypertension' or 'pathophysiology' and 'diagnosis' and 'treatment' or "role of miRNAs in portal hypertension.

EXPERT OPINION

Interestingly, biomarkers like microRNAs (miRNAs) have been studied for their potential role in various diseases including hypertension. In recent years, miRNAs have been proved to be an efficient biomarker and therapeutic target and few studies have assessed the roles of miRNAs in PH. The present paper highlights the potential roles of miRNAs in PH.

Bibliometric-analysis visualization and review of non-invasive methods for monitoring and managing the portal hypertension

Background

Portal hypertension monitoring is important throughout the natural course of cirrhosis. Hepatic venous pressure gradient (HVPG), regarded as the golden standard, is limited by invasiveness and technical difficulties. Portal hypertension is increasingly being assessed non-invasively, and hematological indices, imaging data, and statistical or computational models are studied to surrogate HVPG. This paper discusses the existing non-invasive methods based on measurement principles and reviews the methodological developments in the last 20 years.

Methods

First, we used VOSviewer to learn the architecture of this field. The publications about the non-invasive assessment of portal hypertension were retrieved from the Web of Science Core Collection (WoSCC). VOSviewer 1.6.17.0 was used to analyze and visualize these publications, including the annual trend, the study hotspots, the significant articles, authors, journals, and organizations in this field. Next, according to the cluster analysis result of the keywords, we further retrieved and classified the related studies to discuss.

Results

A total of 1,088 articles or review articles about our topic were retrieved from WoSCC. From 2000 to 2022, the number of publications is generally growing. “World Journal of Gastroenterology” published the most articles (n = 43), while “Journal of Hepatology” had the highest citations. “Liver fibrosis” published in 2005 was the most influential manuscript. Among the 20,558 cited references of 1,088 retrieved manuscripts, the most cited was a study on liver stiffness measurement from 2007. The highest-yielding country was the United States, followed by China and Italy. “Berzigotti, Annalisa” was the most prolific author and had the most cooperation partners. Four study directions emerged from the keyword clustering: (1) the evaluation based on fibrosis; (2) the evaluation based on hemodynamic factors; (3) the evaluation through elastography; and (4) the evaluation of variceal bleeding.

Conclusion

The non-invasive assessment of portal hypertension is mainly based on two principles: fibrosis and hemodynamics. Liver fibrosis is the major initiator of cirrhotic PH, while hemodynamic factors reflect secondary alteration of splanchnic blood flow. Blood tests, US (including DUS and CEUS), CT, and magnetic resonance imaging (MRI) support the non-invasive assessment of PH by providing both hemodynamic and fibrotic information. Elastography, mainly USE, is the most important method of PH monitoring.

Portal hypertension may influence the registration of hypointensity of small hepatocellular carcinoma in the hepatobiliary phase in gadoxetic acid MR

BACKGROUND

The aim of the study was to analyze the association between the liver uptake of Gadolinium-ethoxybenzyl-diethylenetriamine penta-acetic acid (Gd-EOB-DTPA) in the hepatobiliary phase (HBP) in cirrhotic patients and the presence of clinically significant portal hypertension (CSPH), and how these features impact on hepatocellular carcinoma (HCC) detection in the HBP.

PATIENTS AND METHODS

Post-hoc analysis of a prospective cohort of 62 cirrhotic patients with newly US-detected nodule between 1-2 cm (study group). Twenty healthy subjects were used as control group. Qualitative and quantitative analysis of the liver contrast uptake in the HBP assessed by Relative Liver-Enhancement (RLE), Liver-Spleen (LSCR), Liver-Muscle (LMCR), and Liver-Kidney Contrast-Ratio (LKCR), Contrast Enhancement Index (CEI), and Hepatic Uptake (HUI), and biliary excretion, were registered. CSPH was confirmed invasively (HVPG > 10 mmHg) or by indirect parameters. The appearance of HCC at the HBP was analyzed.

RESULTS

Nineteen patients (30.6%) did not have CSPH. In 41 patients (66.1%) the final diagnosis was HCC. All indices were significantly higher in the control group, indicating a more intense HBP liver signal intensity compared to patients with cirrhosis, even if the comparison was restricted to patients with no CSPH. CSPH was associated to a lower rate of HCC hypointensity in the HBP (51.9% vs. 85.7% without CSPH, p = 0.004).

CONCLUSIONS

Liver uptake of Gd-EOB-DTPA at the HBP is decreased in cirrhosis even if the liver function is minimally impaired and it falls down significantly in patients with CSPH compromising the recognition of hypointense lesions. This fact may represent a limitation for the detection of small HCC in patients with cirrhosis and CSPH.