Ethanol-induced alterations of matrix network in the duodenal mucosa of chronic alcohol abusers

Excessive consumption of alcoholic beverages may be associated with gastrointestinal symptoms, including dyspepsia and diarrhoea. It is not clear whether or not chronic alcohol ingestion damages the mucosa of the small intestine. We investigated the effect of chronic alcohol abuse on the duodenal mucosa, and particularly on its extracellular matrix (ECM) network. Duodenal biopsy specimens were obtained during upper gastrointestinal endoscopy from 50 chronic alcoholics without cirrhosis and 10 healthy subjects. Morphological studies were performed by routine histology, immunohistochemistry and electron microscopy. Morphometry of duodenal tissues was performed with a computerized image analyser. No significant duodenal epithelial changes were found in alcoholics, despite an evident reduction in the enterocyte turnover. Myofibroblast-like cells were significantly increased in the villus stroma of alcoholics in comparison to controls. These cells stained positively for desmin, alpha-smooth muscle actin and for several ECM components. In alcohol abusers the thickness of the mucosal basement membrane was greater and the staining for collagen I and III was enhanced both in the basement membrane and in the villus stroma. A higher expression of tenascin was also seen at the base of villi of alcoholics. Chronic alcohol abuse may induce fibrosis of duodenal villi which is associated with a transformation of villus juxta-parenchymal cells into active subepithelial myofibroblast-like cells able to produce different ECM components.