Épidémiologie de la maladie alcoolique et nouveaux enjeux

Circulating MicroRNAs as potential biomarkers for alcoholic steatohepatitis

AIMS

To investigate serum miRNA profile in alcoholic steatohepatitis (ASH), evaluate its effect as non-invasive diagnostic tool and to study its targets' function.

METHODS

Microarray and quantitative reverse transcription-polymerase chain reaction (qRT-PCR) were utilized to detect serum miRNAs pattern in a rat ASH model, followed by target prediction with bioinformatics calculation. The functions and pathways of miRNAs' targets were analysed using databases of Gene Ontology and KEGG. The association between dysregulated miRNAs and genes was assessed by MiR-Gene Network. Five top dysregulated miRNAs were also verified in humans.

RESULTS

Eight up-regulated and three down-regulated serum miRNAs were selected as an accurate molecular signature in distinguishing ASH from control. For up-regulated miRNAs, 122 GO and 144 KEGG pathways were significantly enriched, including apoptosis, lipid metabolic process, PPAR signalling pathway. For down-regulated miRNAs, 86 GO and 104 KEGG pathways were enriched, including fatty acid metabolism and insulin signalling pathway. Besides, Ccdc117, Gcom1, Zmynd11 and Zfp423 were found at top list as under common regulation of maximum miRNAs. Moreover, miR-214 had the highest degree of 63 among all miRNAs, followed by miR-203 and miR-539. Similarly, Stat3 and Lyn showed the highest degree of 5 among all downstream targets. All significance analysis of microarrays (SAM) revealed that five top dysregulated miRNAs showed the same tendency in humans.

CONCLUSION

We have reported a unique serum miRNA pattern for non-invasive diagnosis of ASH and provided data reservoir for miRNA and downstream targets exploration.

Ethanol metabolism and its effects on the intestinal epithelial barrier

Ethanol is widely consumed and is associated with an increasing global health burden. Several reviews have addressed the effects of ethanol and its oxidative metabolite, acetaldehyde, on the gastrointestinal (GI) tract, focusing on carcinogenic effects or alcoholic liver disease. However, both the oxidative and the nonoxidative metabolites of ethanol can affect the epithelial barrier of the small and large intestines, thereby contributing to GI and liver diseases. This review outlines the possible mechanisms of ethanol metabolism as well as the effects of ethanol and its metabolites on the intestinal barrier. Limited studies in humans and supporting in vitro data have indicated that ethanol as well as mainly acetaldehyde can increase small intestinal permeability. Limited evidence also points to increased colon permeability following exposure to ethanol or acetaldehyde. In vitro studies have provided several mechanisms for disruption of the epithelial barrier, including activation of different cell-signaling pathways, oxidative stress, and remodeling of the cytoskeleton. Modulation via intestinal microbiota, however, should also be considered. In conclusion, ethanol and its metabolites may act additively or even synergistically in vivo. Therefore, in vivo studies investigating the effects of ethanol and its byproducts on permeability of the small and large intestines are warranted.