EZH2, JMJD3 and UTX epigenetically regulate hepatic plasticity inducing retro-differentiation and proliferation of liver cells

Modification of histones by lysine methylation plays a role in many biological processes, and it is dynamically regulated by several histone methyltransferases and demethylases. The polycomb repressive complex contains the H3K27 methyltransferase EZH2 and controls dimethylation and trimethylation of H3K27 (H3K27me2/3), which trigger gene suppression. JMJD3 and UTX have been identified as H3K27 demethylases that catalyze the demethylation of H3K27me2/3, which in turns lead to gene transcriptional activation. EZH2, JMJD3 and UTX have been extensively studied for their involvement in development, immune system, neurodegenerative disease, and cancer. However, their role in molecular mechanisms underlying the differentiation process of hepatic cells is yet to be elucidated. Here, we show that EZH2 methyltransferase and JMJD3/UTX demethylases were deregulated during hepatic differentiation of human HepaRG cells resulting in a strong reduction of H3K27 methylation levels. Inhibition of JMJD3 and UTX H3K27 demethylase activity by GSK-J4 epi-drug reverted phenotype of HepaRG DMSO-differentiated cells and human primary hepatocytes, drastically decreasing expression of hepatic markers and inducing cell proliferation. In parallel, inhibition of EZH2 H3K27me3 activity by GSK-126 epi-drug induced upregulation of hepatic markers and downregulated the expression of cell cycle inhibitor genes. To conclude, we demonstrated that modulation of H3K27 methylation by inhibiting methyl-transferase and dimethyl-transferase activity influences the differentiation status of hepatic cells, identifying a possible new role of EZH2, JMJD3 and UTX epi-drugs to modulate hepatic cell plasticity

Alcoholic disease: Liver and beyond

The harmful use of alcohol is a worldwide problem. It has been estimated that alcohol abuse represents the world's third largest risk factor for disease and disability; it is a causal factor of 60 types of diseases and injuries and a concurrent cause of at least 200 others. Liver is the main organ responsible for metabolizing ethanol, thus it has been considered for long time the major victim of the harmful use of alcohol. Ethanol and its bioactive products, acetaldehyde-acetate, fatty acid ethanol esters, ethanol-protein adducts, have been regarded as hepatotoxins that directly and indirectly exert their toxic effect on the liver. A similar mechanism has been postulated for the alcohol-related pancreatic damage. Alcohol and its metabolites directly injure acinar cells and elicit stellate cells to produce and deposit extracellular matrix thus triggering the "necrosis-fibrosis" sequence that finally leads to atrophy and fibrosis, morphological hallmarks of alcoholic chronic pancreatitis. Even if less attention has been paid to the upper and lower gastrointestinal tract, ethanol produces harmful effects by inducing: (1) direct damaging of the mucosa of the esophagus and stomach; (2) modification of the sphincterial pressure and impairment of motility; and (3) alteration of gastric acid output. In the intestine, ethanol can damage the intestinal mucosa directly or indirectly by altering the resident microflora and impairing the mucosal immune system. Notably, disruption of the intestinal mucosal barrier of the small and large intestine contribute to liver damage. This review summarizes the most clinically relevant alcohol-related diseases of the digestive tract focusing on the pathogenic mechanisms by which ethanol damages liver, pancreas and gastrointestinal tract

Gut microbiota and irritable bowel syndrome

Irritable bowel syndrome (IBS) is the commonest functional gastrointestinal disorder, affecting between 10% and 20% of the adult population worldwide. Recently, IBS research has focused on organic components of causative factors such as gut microbiota that in turn may trigger at mucosal level low-grade inflammation and immune activation. To date, four main lines of reasoning support the role of gut microbiota in the pathogenesis of IBS: 1) IBS develops in up to 30% of individuals recovering from acute gastroenteritis "post-infective IBS"; 2) small intestinal bacterial overgrowth (SIBO) is characterized by symptoms like IBS; 3) quantitative and qualitative alterations in gut microbiota "dysbiosis "have been reported in subjects with IBS; 4) IBS symptoms can be improved by treatments (antibiotics, probiotics, prebiotics) that target the microbiota. These arguments open the way to new therapeutic options to treat patients with IBS by the administration of antibiotics, probiotics and perhaps prebiotics. Antibiotic treatment results in significant improvement rates in IBS symptoms; however, side or systemic effects, drug resistance and cost limit the chronic use. Many studies report a positive effect of probiotics, however, at present randomized placebo-controlled trials taking into account well-defined and measurable endpoints and a long follow-up should be planned

Effects of Early Placement of Transjugular Portosystemic Shunts in Patients With High-Risk Acute Variceal Bleeding: a Meta-analysis of Individual Patient Data

BACKGROUND & AIMS: Compared with drugs plus endoscopy, placement of transjugular portosystemic shunt within 72 hours of admission to the hospital (early or preventive transjugular intrahepatic portosystemic shunt [TIPS], also called preemptive TIPS) increases the proportion of high-risk patients with cirrhosis and acute variceal bleeding who survive for 1 year. However, the benefit of preemptive TIPS is less clear for patients with a Child-Pugh score of B and active bleeding (CP-B+AB). We performed an individual data meta-analysis to assess the efficacy of preemptive TIPS in these patients and identify factors associated with reduced survival of patients receiving preemptive TIPS. METHODS: We searched publication databases for randomized controlled trials and observational studies comparing the effects of preemptive TIPS versus endoscopy plus nonselective beta-blockers in the specific population of high-risk patients with cirrhosis and acute variceal bleeding (CP-B+AB or Child-Pugh C, below 14 points), through December 31, 2019. We performed a meta-analysis of data from 7 studies (3 randomized controlled trials and 4 observational studies), comprising 1327 patients (310 received preemptive TIPS and 1017 received drugs plus endoscopy). We built adjusted models to evaluate risk using propensity score for baseline covariates. Multivariate Cox regression models were used to assess the factors associated with survival time. The primary endpoint was effects of preemptive TIPS versus drugs plus endoscopy on 1-year survival in the overall population as well as CP-B+AB and Child-Pugh C patients. RESULTS: Overall, preemptive TIPS significantly increased the proportion of high-risk patients with cirrhosis and acute variceal bleeding who survived for 1 year, compared with drugs plus endoscopy (hazard ratio [HR] 0.443; 95% CI 0.323-0.607; P < .001). This effect was observed in CP-B+AB patients (HR 0.524; 95% CI 0.307-0.896; P = .018) and in patients with Child-Pugh C scores below 14 points (HR 0.374; 95% CI 0.253-0.553; P < .001). Preemptive TIPS significantly improved control of bleeding and ascites without increasing risk of hepatic encephalopathy in Child-Pugh C and CP-B+AB patients, compared with drugs plus endoscopy. Cox analysis of patients who received preemptive TIPS showed that patients could be classified into 3 categories for risk of death, based on age, serum level of creatinine, and Child-Pugh score. In each of these risk categories, preemptive TIPS increased the proportion of patients who survived for 1 year, compared with drugs plus endoscopy. CONCLUSIONS: In a meta-analysis of data from 1327 patients with cirrhosis, acute variceal bleeding, and Child-Pugh score between 10 and 13 points or CP-B+AB, preemptive TIPS increased the proportion who survived for 1 year, in both subgroups separately, compared with drugs plus endoscopy.status: publishe

Liver transplantation for severe alcoholic hepatitis: a multicentre Italian study

There is increasing evidence that early liver transplantation (eLT), performed within standardized protocols can improve survival in severe alcoholic hepatitis (sAH). The aim of the study was to assess outcomes after eLT for sAH in four Italian LT cent- ers and to compare them with non-responders to medical therapy excluded from eLT. Patients admitted for sAH (2013–2019), according to NIAAA criteria, were in- cluded. Patients not responding to medical therapy were placed on the waiting list for eLT after a strict selection. Histological features of explanted livers were evaluated. Posttransplant survival and alcohol relapse were evaluated. Ninety-three patients with severe AH were evaluated (65.6% male, median [IQR] age: 47 [42–56] years). Forty-five of 93 patients received corticosteroids, 52 of 93 were non-responders and among these, 20 patients were waitlisted. Sixteen patients underwent LT. Overall, 6-, 12-, and 24-month survival rates were 100% significantly higher compared with non- responders to medical therapy who were denied LT (45%, 45%, and 36%; p &lt; .001). 2/16 patients resumed alcohol intake, one at 164 days and one at 184 days. Early LT significantly improves survival in sAH non-responding to medical therapy, when a strict selection process is applied. Further studies are needed to properly assess alcohol relapse rate