Microbiota-driven gut vascular barrier disruption is a prerequisite for non-alcoholic steatohepatitis development.

BACKGROUND & AIMS: Fatty liver disease, including non-alcoholic fatty liver (NAFLD) and steatohepatitis (NASH), has been associated with increased intestinal barrier permeability and translocation of bacteria or bacterial products into the blood circulation. In this study, we aimed to unravel the role of both intestinal barrier integrity and microbiota in NAFLD/NASH development. METHODS: C57BL/6J mice were fed with high-fat diet (HFD) or methionine-choline-deficient diet for 1 week or longer to recapitulate aspects of NASH (steatosis, inflammation, insulin resistance). Genetic and pharmacological strategies were then used to modulate intestinal barrier integrity. RESULTS: We show that disruption of the intestinal epithelial barrier and gut vascular barrier (GVB) are early events in NASH pathogenesis. Mice fed HFD for only 1 week undergo a diet-induced dysbiosis that drives GVB damage and bacterial translocation into the liver. Fecal microbiota transplantation from HFD-fed mice into specific pathogen-free recipients induces GVB damage and epididymal adipose tissue enlargement. GVB disruption depends on interference with the WNT/ß-catenin signaling pathway, as shown by genetic intervention driving ß-catenin activation only in endothelial cells, preventing GVB disruption and NASH development. The bile acid analogue and farnesoid X receptor agonist obeticholic acid (OCA) drives ß-catenin activation in endothelial cells. Accordingly, pharmacologic intervention with OCA protects against GVB disruption, both as a preventive and therapeutic agent. Importantly, we found upregulation of the GVB leakage marker in the colon of patients with NASH. CONCLUSIONS: We have identified a new player in NASH development, the GVB, whose damage leads to bacteria or bacterial product translocation into the blood circulation. Treatment aimed at restoring ß-catenin activation in endothelial cells, such as administration of OCA, protects against GVB damage and NASH development. LAY SUMMARY: The incidence of fatty liver disease is reaching epidemic levels in the USA, with more than 30% of adults having NAFLD (non-alcoholic fatty liver disease), which can progress to more severe non-alcoholic steatohepatitis (NASH). Herein, we show that disruption of the intestinal epithelial barrier and gut vascular barrier are early events in the development of NASH. We show that the drug obeticholic acid protects against barrier disruption and thereby prevents the development of NASH, providing further evidence for its use in the prevention or treatment of NASH.

Low anthracyclines doses-induced cardiotoxicity in acute lymphoblastic leukemia long-term female survivors.

BACKGROUND: High dosage anthracyclines in pediatric patients with acute lymphoblastic leukemia (ALL) is associated with cardiotoxicity. However, data on the cardiac effects of lower cumulative doses of these drugs are not conclusive. The aim of this study was to assess the cardiac effects of low cumulative anthracycline doses in long-term survivors of ALL. PROCEDURE: Echocardiograms were performed on 62 long-term ALL survivors, without any overt or sub-clinical signs or symptoms of heart failure. The interval after stopping therapy was 12.6 ± 4.3 years; the mean cumulative dose of anthracyclines was 228.2 ± 42.3 mg/m(2) . Left ventricular (LV) structure and function were studied by echocolor-Doppler. An age, gender and body surface area (BSA) matched group of healthy subjects was used as controls. Cardiac data were analyzed before and after BSA normalization. RESULTS: Long term survivors of ALL, showed a lower LV mass index, interventricular septal and posterior wall thickness, which were independently related to gender and to age at which the ALL diagnosis was made. Data analyzed according to gender showed that abnormalities were confined to the female group. No alterations were observed in the ALL male group versus the corresponding control group. No relationship was observed between the echocardiografic abnormalities and the duration of follow-up or the anthracycline mean dose employed. CONCLUSIONS: In the absence of any signs or symptoms of heart failure, female ALL survivors treated with low cumulative anthracycline doses, showed a reduced LV mass and wall thickness. This suggests that in female ALL survivors an echocardyographic follow-up should be recommended.