[Recent studies on Ito cells with molecular biology].

By Northern blot analysis of total RNA, extracted from normal human and rat Ito cells, either freshly isolated or in culture, recent studies demonstrated the expression of mRNA for collagen type I, III, IV, fibronectin, laminin, transforming growth factor-beta (TGF-beta), hepatocyte growth factor, nuclear retinoic acid receptor-beta and alpha-smooth m muscle actin. Moreover, Ito cells isolated from experimentally induced fibrotic livers exhibited a marked increase in mRNA for collagen type I, associated with a moderate increase in mRNA of collagen type III and TGF-beta. Although endothelial cells from the same liver also showed moderate increase in mRNA for collagen type I alone, hepatocytes showed no changes. From these results it is concluded that Ito cells are the most important cells in hepatic fibrogenesis.