The role of Ito cells in the biosynthesis of HGF-SF in the liver.

Hepatocyte Growth Factor-Scatter Factor (HGF-SF) is produced by sinusoidal cells in normal rat liver. Analysis of isolated cells has proven that Ito cells (fat-storing cells, hepatic lipocytes) are the source of hepatic HGF. In diseased liver the HGF-expression pattern is more complex. In acute liver injury HGF is expressed by an increased number of resident liver cells, which may be due to recruitment of other nonparenchymal liver cells as well as an increased number of Ito cells due to cell division. In cirrhotic rat liver tissue, the number of HGF-expressing cells is decreased. This may be explained by the complete loss of HGF-expression in myofibroblast-like cells derived from Ito cells. Quiescent Ito cells seem to be in a strategic position to control parenchymal cell proliferation. Activation of Ito cells, which occurs in chronic fibrotic liver disease, may lead to the loss of this control function.