Nonalcoholic fatty liver disease prevalence is soaring with the obesity pandemic, but the pathogenic mechanisms leading to the progression toward active nonalcoholic steatohepatitis (NASH) and fibrosis, major causes of liver-related death, are poorly defined. To identify key components during the progression toward NASH and fibrosis, we investigated the liver transcriptome in a human cohort of NASH patients. The transition from histologically proven fatty liver to NASH and fibrosis was characterized by gene expression patterns that successively reflected altered functions in metabolism, inflammation, and epithelial-mesenchymal transition. A meta-analysis combining our and public human transcriptomic datasets with murine models of NASH and fibrosis defined a molecular signature characterizing NASH and fibrosis and evidencing abnormal inflammation and extracellular matrix (ECM) homeostasis. Dermatopontin expression was found increased in fibrosis, and reversal of fibrosis after gastric bypass correlated with decreased dermatopontin expression. Functional studies in mice identified an active role for dermatopontin in collagen deposition and fibrosis. PPARα activation lowered dermatopontin expression through a transrepressive mechanism affecting the Klf6/TGFβ1 pathway. Liver fibrotic histological damages are thus characterized by the deregulated expression of a restricted set of inflammation- and ECM-related genes. Among them, dermatopontin may be a valuable target to reverse the hepatic fibrotic process.

Patients with autoimmune hepatitis (AIH) almost inevitably require lifelong immunosuppressive treatment. There is genuine concern about the efficacy and tolerability of the current standard combination therapy of prednisolone and azathioprine. Mycophenolate mofetil (MMF) has emerged as an alternative option. The aim of this study was to compare MMF to azathioprine as induction therapy. In this 24-week, prospective, randomised, open-label, multicentre superiority trial, 70 patients with treatment-naive AIH received either MMF or azathioprine, both in combination with prednisolone. The primary endpoint was biochemical remission defined as normalisation of serum levels of alanine aminotransferase and immunoglobulin G after 24 weeks of treatment. Secondary endpoints included safety and tolerability. Seventy patients (mean 57.9 years (standard deviation (SD) 14.0); 72.9% female) were randomly assigned to the MMF plus prednisolone (n=39) or azathioprine plus prednisolone (n=31) group. The primary endpoint was met in 56.4% and 29.0% of patients assigned to the MMF group and the azathioprine group, respectively (difference, 27.4 percentage points; 95% confidence interval (CI), 4.0 to 46.7; p=0.022). The MMF group exhibited higher complete biochemical response rates at 6 months (72.2% vs. 32.3%; p=0.004). No serious adverse events occurred in patients who received MMF (0%) but serious adverse events were reported in four patients who received azathioprine (12.9%) (p=0.034). Two patients in the MMF group (5.1%) and eight patients in the azathioprine group (25.8%) discontinued treatment owing to adverse events or serious adverse events (p=0.018). In patients with treatment-naive AIH, MMF with prednisolone achieved a significantly higher rate of biochemical remission at 24 weeks compared to azathioprine combined with prednisolone. Azathioprine use was associated with more (serious) adverse events leading to cessation of treatment, suggesting superior tolerability of MMF. This randomised controlled trial directly compares azathioprine and mycophenolate mofetil (MMF), both in combination with prednisolone, for the induction of biochemical remission in treatment-naive patients with autoimmune hepatitis (AIH). Achieving complete remission is desirable to prevent disease progression. Patients assigned to the MMF group reached biochemical remission more often and experienced fewer adverse events. The findings in this trial may contribute to the re-evaluation of international guidelines for the standard of care in treatment-naive patients with AIH. #NCT02900443.

Genotype 3 (gt3) hepatitis E virus (HEV) infections are emerging in Western countries. Immunosuppressed patients are at risk of chronic HEV infection and progressive liver damage, but no adequate model system currently mimics this disease course. Here we explore the possibilities of in vivo HEV studies in a human liver chimeric mouse model (uPA ^+/+ Nod-SCID-IL2Rγ ^−/− ) next to the A549 cell culture system, using HEV RNA-positive EDTA-plasma, feces, or liver biopsy specimens from 8 immunocompromised patients with chronic gt3 HEV. HEV from feces- or liver-derived inocula showed clear virus propagation within 2 weeks after inoculation onto A549 cells, compared to slow or no HEV propagation of HEV RNA-positive, EDTA-plasma samples. These in vitro HEV infectivity differences were mirrored in human-liver chimeric mice after intravenous (i.v.) inoculation of selected samples. HEV RNA levels of up to 8 log IU HEV RNA/gram were consistently present in 100% of chimeric mouse livers from week 2 to week 14 after inoculation with human feces- or liver-derived HEV. Feces and bile of infected mice contained moderate to large amounts of HEV RNA, while HEV viremia was low and inconsistently detected. Mouse-passaged HEV could subsequently be propagated for up to 100 days in vitro . In contrast, cell culture-derived or seronegative EDTA-plasma-derived HEV was not infectious in inoculated animals. In conclusion, the infectivity of feces-derived human HEV is higher than that of EDTA-plasma-derived HEV both in vitro and in vivo . Persistent HEV gt3 infections in chimeric mice show preferential viral shedding toward mouse bile and feces, paralleling the course of infection in humans. IMPORTANCE Hepatitis E virus (HEV) genotype 3 infections are emerging in Western countries and are of great concern for immunosuppressed patients at risk for developing chronic HEV infection. Lack of adequate model systems for chronic HEV infection hampers studies on HEV infectivity and transmission and antiviral drugs. We compared the in vivo infectivity of clinical samples from chronic HEV patients in human liver chimeric mice to an in vitro virus culture system. Efficient in vivo HEV infection is observed after inoculation with feces- and liver-derived HEV but not with HEV RNA-containing plasma or cell culture supernatant. HEV in chimeric mice is preferentially shed toward bile and feces, mimicking the HEV infection course in humans. The observed in vivo infectivity differences may be relevant for the epidemiology of HEV in humans. This novel small-animal model therefore offers new avenues to unravel HEV's pathobiology.

Metabolic dysfunction-associated steatotic liver disease (MASLD) is a leading cause of advanced chronic liver disease (ACLD). Portal hypertension drives hepatic decompensation and is best diagnosed by hepatic venous pressure gradient (HVPG) measurement. Here we investigate the prognostic value of HVPG in compensated (cACLD) MASLD. This European multicentre study included MASLD-cACLD patients characterised by HVPG at baseline. Hepatic decompensation (variceal bleeding/ ascites/hepatic encephalopathy) and liver-related mortality were considered the primary events of interest. 340 MASLD-cACLD patients [56.2% men; age: 62 (55-68) years; MELD: 8 (7-9); 71.2% diabetes] were included. Clinically significant portal hypertension (CSPH; i.e., HVPG ≥10 mmHg) was found in 209 patients (61.5%). During a median follow-up of 41.5 (27.5-65.8) months, 65 patients developed hepatic decompensation with a cumulative incidence of 10.0% after 2 years (2Y) and 30.7% after 5 years (5Y) in MASLD-cACLD with CSPH, compared to 2.4% after 2Y and 9.4% after 5Y in patients without CSPH. Variceal bleeding did not occur without CSPH. CSPH (subdistribution hazard ratio, SHR:5.13; p<0.001) was associated with an increased decompensation risk and a higher HVPG remained an independent risk factor in the multivariable model (aSHR per mmHg:1.12; p<0.001). Liver-related mortality occurred in 37 patients with a cumulative incidence of 3.3% after 2Y and 21.4% after 5Y in CSPH. Without CSPH, the incidence after 5Y was 0.8%. Accordingly, a higher HVPG was also independently associated with a higher risk of liver-related death (aSHR per mmHg:1.20; p<0.001). HVPG measurement is of high prognostic value in MASLD-cACLD. While MASLD-cACLD patients without CSPH show a very low short-term risk of decompensation and liver-related mortality is rare, the presence of CSPH substantially increases both risks. While the incidence of compensated advanced chronic liver disease (cACLD) due to metabolic dysfunction-associated steatotic liver disease (MASLD) is increasing worldwide, insights into the impact of clinically significant portal hypertension (CSPH) on the risk of liver-related events in MASLD-cACLD remain limited. Based on the findings of this European multicentre study including 340 MASLD-cACLD, we could show that increasing HVPG values and the presence of CSPH in particular were associated with a significantly higher risk of first hepatic decompensation and liver-related mortality. In contrast, the short-term incidence of decompensation in MASLD-cACLD patients without CSPH was low and the risk of liver-mortality remained negligible. Thus, HVPG measurements can provide important prognostic information for individualised risk-stratification in MASLD-cACLD and may help facilitate the study of novel and promising treatment possibilities for MASLD.