2A). The increase of deactivated HSC in SVIGF-I-treated livers is also suggested by the enhanced expression of neurotrimin, a marker of nonactivated HSC12 (Supporting Fig. 2B). We investigated whether the decrease in fibrosis observed in SVIGF-I-treated buy CYC202 rats was associated with activation of enzymes capable of removing collagen, such as MMPs. We found that as compared to normal rats, MMP1, 2, 9, and 14 mRNAs were down-regulated in control cirrhotic
livers and markedly up-regulated in the livers that received SVIGF-I (Fig. 5A). In addition, liver expression of the MMP inhibitors TIMP-1 and TIMP-2 showed a pattern opposite to that of MMPs. Navitoclax in vitro These TIMPs were induced in the liver from Ci and Ci+Luc rats, whereas they were down-regulated in Ci+IGF-I rats (Fig. 5B,C). In agreement with these data we found decreased MMP activity in control cirrhotic livers compared to healthy controls, whereas MMP activity was significantly higher in IGF-I-treated rats
than in healthy controls. It seems possible therefore that increased MMP activity may account for the efficient removal of fibrous tissue from the cirrhotic liver of SVIGF-I-treated rats. In agreement with the above data we observed reduced TGFβ expression in the liver of Ci+IGF-I rats (Fig. 6A). Because TGFβ is a powerful activator of HSCs and the most potent accelerator of liver fibrosis, its down-regulation by IGF-I might be a key factor underlying the antifibrogenic effect of the treatment.13 In addition to TGFβ, other molecules that promote HSC growth
and contribute to liver fibrosis such as amphiregulin (AR), connective tissue growth factor (CTGF), platelet-derived growth factor (PDGF), and vascular endothelium growth factor (VEGF)14–16 were up-regulated in control cirrhotic livers but markedly suppressed in those treated with SVIGF-I as compared to control 上海皓元医药股份有限公司 cirrhotic rats (Fig. 6B–E). Together with the decrease of profibrogenic molecules, we found a significant increase in the expression of hepatocyte growth factor (HGF) and of the HGF receptor c-met in the liver of Ci+IGF-I rats as compared to control animals (Fig. 6F and Supporting Fig. 3). Because HGF displays potent antifibrogenic activities, up-regulation of this molecule and of its receptor may contribute to the regression of liver cirrhosis observed in IGF-I-treated rats.17 We tested the safety of SVIGF-I therapy in cirrhotic rats for more than 8 months after vector injection and we found no signs of toxicity for the entire observation period (data not shown). Necropsies revealed no apparent systemic abnormalities and liver histology confirmed the absence of malignant or premalignant lesions.