Liver fibrosis is associated with cutaneous inflammation the imiquimod-induced murine model of psoriasiform dermatitis

Background Psoriasis exhibits several extracutaneous manifestations. Little is known about hepatic parameters specifically associated with psoriasis. Objectives To study whether psoriasiform dermatitis is associated with liver injury. Methods We studied liver parameters of inflammation and fibrosis in a murine model of psoriasiform dermatitis induced by topical application of imiquimod for 9 weeks. Results Topical treatment with imiquimod induced a form of psoriasiform dermatitis reminiscent of the human disorder, characterized by thickened and scaly skin, psoriasiform epidermal hyperplasia, altered keratinocyte differentiation and cutaneous overexpression of interleukin-17A. Mice with dermatitis displayed hepatitis, as shown by elevation of plasma transaminase levels as well as portal and periportal hepatitis, characterized by T-lymphocyte (CD3 epsilon(+)) and polymorphonu-clear cell (Gr1(+)) infiltrates. The hepatitis progressed towards liver fibrogenesis, as shown by excessive Sirius red staining, which is consistent with the expression of alpha-smooth muscle actin by hepatic stellate cells. Conclusions These results indicate that liver inflammation and fibrosis are associated with experimental psoriasiform dermatitis. Our results suggest that psoriatic inflammation may be associated with specific liver injury.