The isomers all-trans and 9-cis retinoic acid alter activated stellate cells differentially.

In healthy liver the most characteristic feature of stellate cells is the presence of retinoid-rich lipid droplets in the cytoplasm. Activation of stellate cells is correlated with loss of these vitamin A reserves. The aim of the present study was to examine the influence of all-trans retinoic acid (ATRA) and 9-cis retinoic acid (9RA) on extracellular matrix production and proliferation of activated hepatic stellate cells. Here we demonstrate that ATRA and 9RA exert different often contrary effects on activated stellate cells. Our observations may explain prior divergent results obtained following retinoid administration to cultured stellate cells or to animals subjected to fibrogenic stimuli.