Impact of farnesoid X receptor single nucleotide polymorphisms on hepatic decompensation and mortality in cirrhotic patients with portal hypertension

Role of Intestinal Barrier Disruption to Acute-on-Chronic Liver Failure

Acute-on-chronic liver failure (ACLF) is a severe condition in patients with decompensated liver cirrhosis, marked by high short-term mortality. Recent experimental and clinical evidence has linked intestinal dysfunction to both the initiation of ACLF as well as disease outcome. This review discusses the significant role of the gut-liver axis in ACLF pathogenesis, highlighting recent advances. Gut mucosal barrier disruption, gut dysbiosis, and bacterial translocation emerge as key factors contributing to systemic inflammation in ACLF. Different approaches of therapeutically targeting the gut-liver axis via farnesoid X receptor agonists, nonselective beta receptor blockers, antibiotics, and probiotics are discussed as potential strategies mitigating ACLF progression. The importance of understanding the distinct pathophysiology of ACLF compared with other stages of liver cirrhosis is highlighted. In conclusion, research findings suggest that disruption of intestinal integrity may be an integral component of ACLF pathogenesis, paving the way for novel diagnostic and therapeutic approaches to manage this syndrome more effectively.

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.

Roles of NR1I3 and NR1H4 polymorphisms in the susceptibility to antituberculosis drug-induced liver injury in China: a case‒control study

Objective

The pathogenesis of antituberculosis drug-induced liver injury (AT-DILI) remains largely unknown. The current investigation aimed to determine the genetic contribution of the nuclear receptor subfamily 1 Group I member 3 (NR1I3) and nuclear receptor subfamily 1 Group H member 4 (NR1H4) genes to the risk of AT-DILI in the Chinese population.

Methods

A 1:4 matched case‒control study was conducted, and five single nucleotide polymorphisms (SNPs) in the NR1I3 and NR1H4 genes were detected and assessed. Utilizing a multivariate conditional logistic regression model, the effects of haplotype and genotype on the risk of AT-DILI were examined. Extended subgroup analysis was carried out based on sex. The distribution of the peak value of serum liver enzymes also compared among different genotypes.

Results

224 AT-DILI cases and 896 controls were included in this study. No significant difference was observed in genotypes or haplotypes frequencies between AT-DILI cases and controls. However, comparisons of liver function indicators revealed significant differences in the peak values of alanine aminotransferase (ALT), aspartate aminotransferase (AST) and total bilirubin (TBil) among patients with different genotypes of NR1H4 rs56163822 (GG vs. GT vs. TT, 27.1 U/L vs. 26.0 U/L vs. 23.0 U/L, p = 0.020; 34.0 U/L vs. 31.0 U/L vs. 30.6 U/L, p = 0.008; 15.5 μmol/L vs. 15.0 μmol/L vs. 13.7 μmol/L, p = 0.029, respectively), as well as in the peak values of ALT and AST among male patients with different genotypes of NR1H4 rs56163822 (29.0 U/L vs. 26.9 U/L vs. 22.6 U/L, p = 0.002; 34.0 U/L vs. 32.0 U/L vs. 30.5 U/L, p = 0.019, respectively).

Conclusion

Based on this 1:4 individual-matched case‒control study, the SNP rs56163822 in the NR1H4 gene may be linked to the susceptibility to AT-DILI in Chinese patients receiving anti-TB treatment. Further studies in larger varied populations are needed to validate our findings.

Pathophysiology and therapeutic options for cirrhotic portal hypertension

Portal hypertension represents the primary non-neoplastic complication of liver cirrhosis and has life-threatening consequences, such as oesophageal variceal bleeding, ascites, and hepatic encephalopathy. Portal hypertension occurs due to increased resistance of the cirrhotic liver vasculature to portal blood flow and is further aggravated by the hyperdynamic circulatory syndrome. Existing knowledge indicates that the profibrogenic phenotype acquired by sinusoidal cells is the initial factor leading to increased hepatic vascular tone and fibrosis, which cause increased vascular resistance and portal hypertension. Data also suggest that the phenotype of hepatic cells could be further impaired due to the altered mechanical properties of the cirrhotic liver itself, creating a deleterious cycle that worsens portal hypertension in the advanced stages of liver disease. In this Review, we discuss recent discoveries in the pathophysiology and treatment of cirrhotic portal hypertension, a condition with few pharmacological treatment options.

Factor VIII/protein C ratio independently predicts liver-related events but does not indicate a hypercoagulable state in ACLD

BACKGROUND & AIMS

It has been suggested that the ratio of procoagulant factor VIII to anticoagulant protein C (FVIII/PC) reflects the hemostatic equilibrium. Moreover, FVIII/PC predicted decompensation/death in a small study not accounting for portal hypertension severity. We investigated (i) the prognostic value of FVIII/PC (outcome-cohort) and (ii) whether FVIII/PC reflects the hypercoagulable state (assessed by thrombomodulin-modified thrombin generation assay [TM-TGA]) or the risk of bleeding/thrombotic events in patients undergoing hepatic venous pressure gradient (HVPG) measurement during follow-up.

METHODS

(i) The outcome-cohort comprised 576 patients with evidence of advanced chronic liver disease (liver stiffness measurement ≥10 kPa and/or HVPG ≥6 mmHg). (ii) TM-TGA-cohort patients (n = 142) were recruited from the prospective VIenna CIrrhosis Study (VICIS: NCT03267615).

RESULTS

(i) FVIII/PC significantly increased across clinical stages (p <0.001) as well as HVPG (p <0.001) and MELD score (p <0.001) strata and remained independently associated with decompensation/liver-related death (adjusted hazard ratio 1.06; 95% CI 1.01-1.11; p = 0.013), even after multivariable adjustment. It was also associated with acute-on-chronic liver failure (ACLF) development (adjusted hazard ratio 1.10; 95% CI 1.02-1.19; p = 0.015) in patients with decompensated cirrhosis. (ii) FVIII/PC showed a weak positive correlation with endogenous thrombin potential (Spearman's ρ = 0.255; p = 0.002), but this association disappeared after adjusting for the severity of liver disease. FVIII/PC was not associated with the development of bleeding (p = 0.272) or thrombotic events (p = 0.269). However, FVIII/PC correlated with biomarkers of different pathophysiological mechanisms that promote liver disease progression.

CONCLUSION

FVIII/PC provides prognostic information regarding hepatic decompensation/death and ACLF, independently of established prognostic indicators. However, this is not evidence that hypercoagulability drives disease progression, as the correlation between FVIII/PC and thrombin generation is confounded by liver disease severity and FVIII/PC was not associated with thrombosis. Therefore, FVIII/PC does not reflect coagulation and results from previous studies on FVIII/PC require re-interpretation.

CLINICAL TRIAL NUMBER

NCT03267615 (in part).

LAY SUMMARY

A balanced coagulation system is essential for preventing bleeding episodes and blood clot formation (thrombosis). Blood of patients with advanced liver disease may have increased coagulation potential, possibly promoting the worsening of liver disease via thrombosis in the blood vessels of the liver. The ratio between the results of 2 blood tests (procoagulant factor VIII to anticoagulant protein C) has been suggested to reflect these increases in coagulation potential. Our study demonstrates, on the one hand, that this ratio is a versatile predictor of the development of complications of cirrhosis, yet on the other hand, that it is unrelated to coagulation.

Distinct prognostic value of different portal hypertension-associated features in patients with primary biliary cholangitis

BACKGROUND

Primary biliary cholangitis (PBC) may progress to cirrhosis and clinically significant portal hypertension (CSPH). This study assesses different features of CSPH and their distinct prognostic impact regarding decompensation and survival in patients with PBC.

METHODS

Patients with PBC were identified during a database query of our digital patient reporting system.

RESULTS

A total of 333 PBC patients (mean age 54.3 years, 86.8% females, median follow-up 5.8 years) were retrospectively assessed and 127 (38.1%) showed features of CSPH: 63 (18.9%) developed varices, 98 (29.4%) splenomegaly, 62 (18.6%) ascites and 20 (15.7%) experienced acute variceal bleeding. Splenomegaly, portosystemic collaterals and esophageal varices were associated with an increased 5-year (5Y) risk of decompensation (15.0%, 17.8% and 20.9%, respectively). Patients without advanced chronic liver disease (ACLD) had a similar 5Y-transplant free survival (TFS) (96.6%) compared to patients with compensated ACLD (cACLD) but without CSPH (96.9%). On the contrary, PBC patients with cACLD and CSPH (57.4%) or decompensated ACLD (dACLD) (36.4%) had significantly decreased 5Y survival rates. The combination of LSM < 15 kPa and platelets ≥ 150G/L indicated a negligible risk for decompensation (5Y 0.0%) and for mortality (5Y 0.0%). Overall, 44 (13.2%) patients died, with 18 (40.9%) deaths attributed to CSPH-related complications.

CONCLUSION

In PBC, features of CSPH may occur early and indicate an increased risk for subsequent decompensation and mortality. Hence, regular screening and on-time treatment for CSPH is crucial. Combining LSM and platelets serves as a valuable preliminary assessment, as LSM < 15 kPa and platelets ≥ 150G/L indicate an excellent long-term outcome.

NR1H4 rs35724 G>C variant modulates liver damage in nonalcoholic fatty liver disease

BACKGROUND AND AIMS

Farnesoid X receptor (FXR) plays a key role in bile acid and lipid homeostasis. Experimental evidence suggests that it can modulate liver damage related to nonalcoholic fatty liver disease (NAFLD). We examined the impact of the NR1H4 rs35724 G>C, encoding for FXR, on liver damage in a large cohort of patients at risk of steatohepatitis.

METHODS

We considered 2,660 consecutive individuals at risk of steatohepatitis with liver histology. The rs35724 G>C polymorphisms were genotyped by TaqMan assays. Gene expression was evaluated by RNASeq in a subset of patients (n = 124).

RESULTS

The NR1H4 rs35724 CC genotype, after adjusting for clinic-metabolic and genetic confounders and for enrolling centre, was protective against severity of steatosis (GG vs CC OR 0.77, 95% CI 0.62-0.95; P = .01), steatohepatitis (GG vs CC OR 0.62, 95% CI 0.47-0.83; P = .001) and severity of fibrosis (GG vs CC OR 0.83, 95% CI 0.67-0.98; P = .04). The C allele was associated with higher total circulating cholesterol (P = .01). Patients carrying the NR1H4 rs35724 C allele had significantly higher hepatic mRNA levels of FXR and were associated with higher hepatic FGFR4 and Cyp39A1 that are in turn involved in bile acid synthesis.

CONCLUSIONS

Increased hepatic FXR expression due to the NR1H4 rs35724 C allele is linked to higher serum cholesterol but protects against steatosis, steatohepatitis and liver fibrosis. The translational relevance of these results for patient risk stratification and FXR-targeted therapy warrants further investigation.

Portal hypertension in cirrhosis: Pathophysiological mechanisms and therapy

Portal hypertension, defined as increased pressure in the portal vein, develops as a consequence of increased intrahepatic vascular resistance due to the dysregulation of liver sinusoidal endothelial cells (LSECs) and hepatic stellate cells (HSCs), frequently arising from chronic liver diseases. Extrahepatic haemodynamic changes contribute to the aggravation of portal hypertension. The pathogenic complexity of portal hypertension and the unsuccessful translation of preclinical studies have impeded the development of effective therapeutics for patients with cirrhosis, while counteracting hepatic and extrahepatic mechanisms also pose a major obstacle to effective treatment. In this review article, we will discuss the following topics: i) cellular and molecular mechanisms of portal hypertension, focusing on dysregulation of LSECs, HSCs and hepatic microvascular thrombosis, as well as changes in the extrahepatic vasculature, since these are the major contributors to portal hypertension; ii) translational/clinical advances in our knowledge of portal hypertension; and iii) future directions.

Impact of Obeticholic acid Exposure on Decompensation and Mortality in Primary Biliary Cholangitis and Cirrhosis

Obeticholic acid (OCA) is approved for the treatment of patients with primary biliary cholangitis (PBC) who are partial responders or intolerant to ursodeoxycholic acid. Reports of serious liver injury have raised concerns about its safety in cirrhosis. We investigated the effects of treatment with OCA on hepatic decompensation and liver-related mortality or transplantation in a cohort with compensated PBC cirrhosis. This was a retrospective cohort study using national data of US veterans with PBC and cirrhosis. We performed a propensity score model using variables associated with OCA prescription to control for baseline risk of decompensation. New OCA users were matched to nonusers. We identified 509 subjects with compensated PBC cirrhosis. We developed a propensity score model using variables associated with OCA prescription; 21 OCA users were matched with 84 nonusers. Over 569 and 3,847 person-months, respectively, of follow-up, 5 (23.8%) OCA users and 22 (26.2%) OCA nonusers decompensated. The C-statistic of the propensity score model was 0.87. On multivariable analysis, after adjusting for potential confounders, OCA use was associated with an increased risk of hepatic decompensation (adjusted hazard ratio, 3.9; 95% confidence interval, 1.33-11.57; P = 0.01). There was no association between OCA use and liver-related mortality or transplantation (adjusted hazard ratio, 1.35; 95% confidence interval, 0.35-5.21; P = 0.66). Conclusion: OCA use was associated with an increase in hepatic decompensation but not liver-related mortality or transplantation in patients with compensated PBC cirrhosis. Additional studies are recommended to prospectively investigate these findings.

The von Willebrand Factor antigen to platelet ratio (VITRO) score predicts hepatic decompensation and mortality in cirrhosis

BACKGROUND

The ratio of von Willebrand Factor to platelets (VITRO) reflects the severity of fibrosis and portal hypertension and might thus hold prognostic value.

METHODS

Patients with compensated cirrhosis were recruited. VITRO, Child-Pugh score (CPS) and MELD were determined at study entry. Hepatic decompensation was defined as variceal bleeding, ascites or hepatic encephalopathy. Liver transplantation and death were recorded.

RESULTS

One hundred and ninety-four patients with compensated cirrhosis (CPS-A 89%, B 11%; 56% male; median age 56 years; 50% with varices) were included. During a median follow-up of 45 months (IQR 29-61), decompensation occurred in 35 (18%) patients and 14 (7%) patients deceased. The risk of hepatic decompensation was significantly increased in the n = 88 (45%) patients with a VITRO ≥ 2.5 (p < 0.001). Patients with a VITRO ≥ 2.5 had a higher probability of decompensation at 1-year 9% (95% CI 3-16) vs. 0% (95% CI 0-0) and at 2-years 18% (95% CI 10-27%), vs. 4% (95% CI 0-8%) as compared to patients with VITRO < 2.5. Patients with VITRO ≥ 2.5, the estimated 1-year/2-year survival rates were at 98% (95% CI 95-100%) and 94% (95% CI 88-99%) as compared to 100% (95% CI 100-100%) both in the patients with a VITRO < 2.5 (p < 0.001). After adjusting for age, albumin and MELD, VITRO ≥ 2.5 remained as significant predictor of transplant-free mortality (HR 1.38, CI 1.09-1.76; p = 0.007). Patients with compensated cirrhosis and VITRO > 2.1 after hepatitis C eradication remained at significantly increased risk for decompensation (p = 0.033).

CONCLUSIONS

VITRO is a valuable prognostic tool for estimating the risk of decompensation and mortality in patients with compensated cirrhosis-including the setting after hepatitis C eradication.

Gut-liver axis signaling in portal hypertension

Portal hypertension (PHT) in advanced chronic liver disease (ACLD) results from increased intrahepatic resistance caused by pathologic changes of liver tissue composition (structural component) and intrahepatic vasoconstriction (functional component). PHT is an important driver of hepatic decompensation such as development of ascites or variceal bleeding. Dysbiosis and an impaired intestinal barrier in ACLD facilitate translocation of bacteria and pathogen-associated molecular patterns (PAMPs) that promote disease progression via immune system activation with subsequent induction of proinflammatory and profibrogenic pathways. Congestive portal venous blood flow represents a critical pathophysiological mechanism linking PHT to increased intestinal permeability: The intestinal barrier function is affected by impaired microcirculation, neoangiogenesis, and abnormal vascular and mucosal permeability. The close bidirectional relationship between the gut and the liver has been termed “gut-liver axis”. Treatment strategies targeting the gut-liver axis by modulation of microbiota composition and function, intestinal barrier integrity, as well as amelioration of liver fibrosis and PHT are supposed to exert beneficial effects. The activation of the farnesoid X receptor in the liver and the gut was associated with beneficial effects in animal experiments, however, further studies regarding efficacy and safety of pharmacological FXR modulation in patients with ACLD are needed. In this review, we summarize the clinical impact of PHT on the course of liver disease, discuss the underlying pathophysiological link of PHT to gut-liver axis signaling, and provide insight into molecular mechanisms that may represent novel therapeutic targets.