Reduction of Liver Fibrosis by CCR2 Antagonist CCX872 in Murine Models of NASH

Abstract

Introduction: Liver fibrosis in non-alcoholic steatohepatitis (NASH) is caused by chronic inflammation with macrophage infiltration and cytokine production. Inflammatory macrophages express CCR2, which they use to migrate to the liver. We investigated the efficacy of a CCR2 specific inhibitor, CCX872, in two murine models of NASH. Methods: Two models of NASH were used for determining the efficacy of CCX872 in reducing fibrosis. One model used a high-fat diet (HFD) supplemented with 30% fructose in water, for 30 weeks, to induce NASH and liver fibrosis. After 22 weeks on this diet the mice were given CCX872 (30 mg/kg) once daily or vehicle, both administered subcutaneously for 8 weeks. In the second model the mice were fed a methionine-choline diet deficient (MCD) for 8 weeks to induce liver fibrosis. Mice were treated with CCX872 (30 mg/kg) once daily, or vehicle, both administered subcutaneously for 8 weeks. Liver injury was assessed by standard methods. Liver fibrosis was assessed by sirius red staining, and quantified with the computer program “Image J”. Results: In the HFD/fructose model, mice treated with CCX872 showed reduced accumulation of CD11b+ F4/80+ macrophages in the liver, as compared with vehicle treated mice (p=0.03). Mice treated with CCX872 also had improved insulin sensitivity (p < 0.001) and glucose tolerance (p < 0.001) compared with vehicle. Hepatic triglyceride accumulation was significantly lower in CCX872 treated mice (p < 0.01). Treatment with CCX872 significantly reduced both ALT and AST concentrations in HFD diet fed mice (p < 0.0001 for both ALT and AST). Moreover, 8 weeks of treatment with CCX872 significantly reduced collagen content by approximately 50% based on Sirius red staining (p=0.008), as compared with vehicle treated mice. In the MCD model, ALT was also reduced by CCX872 treatment (p=0.03). Administration of CCX872 reduced collagen content by approximately 25% (p=0.035) in MCD diet fed mice. Conclusion: We investigated the efficacy of a clinical-stage small molecule inhibitor of CCR2, CCX872 for the treatment of steatohepatitis in mice. Mice on HFD treated with CCX872 had reduced hepatic inflammation and steatosis as well as improved insulin sensitivity and glucose tolerance, compared to vehicle treated mice. Moreover, treatment with CCX872 had a marked therapeutic effect on improving liver fibrosis in both mice models of NASH. These findings suggest a potential application of CCR2 inhibitor, CCX872, for treatment of patients with NASH.