Activated Ito cells of cirrhotic liver express M3 muscarinic receptor after thioacetamide exposure.

Ito cells or perisinusoidal stellate cells or hepatic fat storing cells are pericytes of normal liver sinusoidal endothelial cells. Activation of Ito cells by chemicals or toxins causes transdifferentiation into the main collagen-producing cells involving in the progression of liver cirrhosis. Quantitative analysis of Ito cell activation by immunohistochemistry has been shown to be useful in predicting the rate of progression of liver fibrosis in some clinical situations. The present study demonstrated that the activated Ito cells in thioacetamide-induced cirrhotic liver which were immunopositive with alpha smooth muscle actin, expressed M3 muscarinic receptor but not M1, M2, M4 and M5. These findings suggest that the M3 muscarinic receptor might involve in triggering intracellular signalling pathways in activated Ito cell to produce collagen fibers and may be of future interest in hepatic fibrosis therapy.