ITGB1 and Hepatic fibrosis: Moreover, in the livers of platelet-derived growth factor receptor beta (Pdgfrb) knock-in reporter mice (Pdgfrb-BAC-eGFP) (ref. 18) there was a greater detection of integrin beta-1 on the surface of live HSCs following 6-week CCl4 induction of liver fibrosis (Fig. 7b,c).