Pharmacological Macrophage Attenuation by Imatinib Reverts Hepatic Steatosis and Inflammation in Obese Mice

Aims Non-alcoholic fatty liver disease (NAFLD) has become one of the most common liver diseases worldwide. As macrophages play a key role in NAFLD, therapies targeting macrophages have been postulated. Indeed, strategies depleting macrophages or blocking monocyte recruitment into the liver improve NAFLD, however, are not feasible in clinical practice. Our goal was to assess whether attenuation of macrophages can be achieved by imatinib, an anti-leukemia drug with known anti-inflammatory and anti-diabetic properties, and how this impacts NAFLD. Materials and Methods Murine macrophages were polarized in vitro to different activation states in the presence or absence of imatinib; mice on high fat diet orally treated with imatinib or vehicle; and human monocytes of diabetic patients and healthy controls treated with or without imatinib for translational application. Results Imatinib specifically attenuated pro-inflammatory murine macrophages in vitro and in vivo . In livers of obese mice, imatinib caused Kupffer cells to adopt an attenuated phenotype via modulation of the TNFα-pathway. This immune-modulation resulted in markedly improved hepatic steatosis along with beneficial effects on liver function, lipids and systemic inflammation. The immune-dampening effect of imatinib also prevailed in human monocytes, indicating translational applicability. Conclusions Immune-modulation of myeloid cells as exemplified by imatinib may be a novel therapeutic strategy in patients with NAFLD.