Lipopolysaccharide modification enhances the inhibitory effect of clodronate liposomes on hepatic fibrosis by depletion of macrophages and hepatic stellate cells.

Hepatic fibrosis is a complex chronic liver disease in which both macrophages and hepatic stellate cells (HSCs) play important roles. Many studies have shown that clodronate liposomes (CLD-lipos) effectively deplete macrophages. However, no liposomes have been developed that target both HSCs and macrophages. This study aimed to evaluate the therapeutic efficacy of lipopolysaccharide-coupled clodronate liposomes (LPS-CLD-lipos) and the effects of liposomes size on hepatic fibrosis. Three rat models of hepatic fibrosis were established in vivo; diethylnitrosamine (DEN), bile duct ligation (BDL), and carbon tetrachloride (CCl4). Hematoxylin and eosin staining and serological liver function indices were used to analyze pathological liver damage. Masson's trichrome and Sirius red staining were used to evaluate the effect of liposomes on liver collagen fibers. The hydroxyproline content in liver tissues was determined. In vitro cell counting kit-8 (CCK-8) and immunofluorescence assays were used to further explore the effects of LPS modification and liposomes size on the killing of macrophages and HSCs. Both in vitro and in vivo experiments showed that 200 nm LPS-CLD-lipos significantly inhibited hepatic fibrosis and the abnormal deposition of collagen fibers in the liver and improved the related indicators of liver function. Further results showed that 200 nm LPS-CLD-lipos increased the clearance of macrophages and induced apoptosis of hepatic stellate cells, significantly. The present study demonstrated that 200 nm LPS-CLD-lipos could significantly inhibit hepatic fibrosis and improve liver function-related indices and this study may provide novel ideas and directions for hepatic fibrosis treatment.

Doxorubicin-liposome combined with clodronate-liposome inhibits hepatocellular carcinoma through the depletion of macrophages and tumor cells.

Macrophages in the liver have capacities of capturing and phagocytosing nanocarriers. Macrophages also play an important role in the inflammatory microenvironment and in the tumorigenesis, development and progression of hepatocellular carcinoma (HCC). Several studies have shown that depletion of macrophages is a viable strategy for drug delivery and tumor microenvironment regulation. We prepared liposomes containing doxorubicin and clodronate using an ammonium sulfate gradient and thin film hydration method. The repressive therapeutic effects of liposomes were compared by intrasplenic injection at different stages of a primary HCC model induced by diethylnitrosamine (DEN) in rats. Doxorubicin-liposome (DOX-LIP) and clodronate-liposome (CL-LIP) about 180-200 nm were successfully prepared and characterized. We found that DOX-LIP combined with CL-LIP could effectively inhibit the occurrence and development of liver cancer without major organ damage and side effects. The combination of doxorubicin and clodronate liposomes notably decreased hepatic CD68 + macrophages, enriched DOX in plasma and accumulated it for a long time in the liver and spleen, thus improving the tumor microenvironment, inhibiting the activation of hepatic progenitor cells (HPCs) and promoting the apoptosis of tumor cells, and finally producing the inhibitory and therapeutic effects of HCC in rats. Results of this study were expected to provide a new prospect for the chemotherapy of HCC.