Influence of Genetic Variants on Disease Regression and Outcomes in HCV-Related Advanced Chronic Liver Disease after SVR

Metabolic phenotyping of patients with advanced chronic liver disease for better characterization of cirrhosis regression

BACKGROUND & AIMS

Regression of cirrhosis has been observed in patients with viral and non-viral etiologies of liver disease in whom the underlying cause of liver injury was effectively suppressed. However, the understanding of the factors contributing to reversibility of fibrosis and cirrhosis is limited. Our aims were to assess clinical factors, perform genotyping of known variants, and comprehensive metabolic phenotyping to characterize the regression of fibrosis in patients with compensated advanced chronic liver disease (cACLD).

METHODS

In a case-control pilot study of 81 patients with cACLD, we compared individuals exhibiting histological or clinical evidence of cACLD regression ("regressors"; n = 44) with those showing no improvement ("non-regressors"; n = 37) after a minimum of 24 months of successful treatment of the cause of liver disease. Data were validated using an external validation cohort (n = 30).

RESULTS

Regardless of the cause of cACLD, the presence of obesity (odds ratio [OR] 0.267 95% CI 0.072-0.882; p = 0.049), high liver stiffness (OR 0.960, 95% CI 0.925-0.995; p = 0.032), and carriage of GCKR variant rs1260326 (OR 0.148, 95% CI 0.030-0.773; p = 0.019) are associated with a reduced likelihood of fibrosis regression in a subgroup of 60 patients with ACLD genotyped for known genetic variants. Using liver tissue transcriptomics, we identified metabolic pathways differentiating regressors from non-regressors, with top pathways associated with lipid metabolism - especially fatty acids, bile acids, phospholipids, triacylglycerides (biosynthesis), and the carnitine shuttle. In the entire discovery cohort, we further measured metabolites within the defined pathways, which led to the identification of 33 circulating markers differentiating regressors from non-regressors after etiological therapy. The validation cohort confirmed 14 of the differentially expressed markers.

CONCLUSIONS

We identified and validated a group of lipid biomarkers associated with regression of fibrosis that could be used as non-invasive biomarkers for detecting regression of fibrosis in cACLD.

IMPACT AND IMPLICATIONS

Regression of cirrhosis/advanced chronic liver disease (ACLD) after removal of the underlying cause of liver injury has been observed in human cirrhosis. However, detailed characterization of ACLD regression remains an unmet need. In this study, we provide a comprehensive phenotyping of individuals likely to experience ACLD regression. While obesity, carriage of GCKR variant rs1260326 and high liver stiffness were associated with lower likelihood of regression of ACLD, a signature of circulating lipid metabolites enabled differentiation of regressors from non-regressors after effective etiologic therapy. The lipid signature we discovered and externally validated could be used as non-invasive biomarker to detect regression of fibrosis in patients with compensated ACLD.

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.

The impact of transmembrane 6 superfamily 2 (TM6SF2) rs58542926 on liver-related events in patients with advanced chronic liver disease

BACKGROUND & AIMS

Genetic factors such as the transmembrane 6 superfamily 2 (TM6SF2) rs58542926 single nucleotide variant(SNV) modulate the susceptibility for (advanced) chronic liver disease ([A]CLD). However, the impact of this variant in patients who have already progressed to ACLD is unknown.

METHODS

The association between TM6SF2-rs58542926 genotype and liver-related events was evaluated in 938 ACLD patients undergoing hepatic venous pressure gradient (HVPG) measurement.

RESULTS

Mean HVPG was 15±7 mmHg and mean UNOS MELD (2016) 11±5 points. Viral hepatitis (n = 495, 53%) was the most common cause of ACLD, followed by alcohol-related (ARLD; n = 342, 37%) and non-alcoholic fatty liver disease (NAFLD; n = 101, 11%). While 754 (80%) patients harboured the TM6SF2 wild-type (C/C), 174 (19%) and 10 (1%) patients had one or two T-alleles. At baseline, patients with at least one TM6SF2 T-allele had more pronounced portal hypertension (HVPG: 16±7 vs. 15±7 mmHg; p = 0.031), higher gamma-glutamyl transferase levels (123 [63-229] vs. 97 [55-174] UxL-1; p = 0.002), and more commonly hepatocellular carcinoma (17% vs. 12%; p = 0.049). Harbouring the TM6SF2 T-allele was associated with the composite endpoint hepatic decompensation/liver transplantation/liver-related death (SHR: 1.44 [95%CI: 1.14-1.83]; p = 0.003). This was confirmed in multivariable competing risk regression analyses that were adjusted for severity of portal hypertension and hepatic dysfunction at baseline.

CONCLUSION

The TM6SF2 variant modulates liver disease progression beyond the development of ACLD, as it modifies the risks of hepatic decompensation and liver-related death, independently of baseline liver disease severity.

HCC risk stratification after cure of hepatitis C in patients with compensated advanced chronic liver disease

BACKGROUND & AIMS

Hepatocellular carcinoma (HCC) is a major cause of morbidity and mortality in patients with advanced chronic liver disease (ACLD) caused by chronic hepatitis C who have achieved sustained virologic response (SVR). We developed risk stratification algorithms for de novo HCC development after SVR and validated them in an independent cohort.

METHODS

We evaluated the occurrence of de novo HCC in a derivation cohort of 527 patients with pre-treatment ACLD and SVR to interferon-free therapy, in whom alpha-fetoprotein (AFP) and non-invasive surrogates of portal hypertension including liver stiffness measurement (LSM) were assessed pre-/post-treatment. We validated our results in 1,500 patients with compensated ACLD (cACLD) from other European centers.

RESULTS

During a median follow-up (FU) of 41 months, 22/475 patients with cACLD (4.6%, 1.45/100 patient-years) vs. 12/52 decompensated patients (23.1%, 7.00/100 patient-years, p <0.001) developed de novo HCC. Since decompensated patients were at substantial HCC risk, we focused on cACLD for all further analyses. In cACLD, post-treatment-values showed a higher discriminative ability for patients with/without de novo HCC development during FU than pre-treatment values or absolute/relative changes. Models based on post-treatment AFP, alcohol consumption (optional), age, LSM, and albumin, accurately predicted de novo HCC development (bootstrapped Harrel's C with/without considering alcohol: 0.893/0.836). Importantly, these parameters also provided independent prognostic information in competing risk analysis and accurately stratified patients into low- (~2/3 of patients) and high-risk (~1/3 of patients) groups in the derivation (algorithm with alcohol consumption; 4-year HCC-risk: 0% vs. 16.5%) and validation (3.3% vs. 17.5%) cohorts. An alternative approach based on alcohol consumption (optional), age, LSM, and albumin (i.e., without AFP) also showed a robust performance.

CONCLUSIONS

Simple algorithms based on post-treatment age/albumin/LSM, and optionally, AFP and alcohol consumption, accurately stratified patients with cACLD based on their risk of de novo HCC after SVR. Approximately two-thirds were identified as having an HCC risk <1%/year in both the derivation and validation cohort, thereby clearly falling below the cost-effectiveness threshold for HCC surveillance.

LAY SUMMARY

Simple algorithms based on age, alcohol consumption, results of blood tests (albumin and α-fetoprotein), as well as liver stiffness measurement after the end of hepatitis C treatment identify a large proportion (approximately two-thirds) of patients with advanced but still asymptomatic liver disease who are at very low risk (<1%/year) of liver cancer development, and thus, might not need to undergo 6-monthly liver ultrasound.