Granulocyte colony stimulating factor treatment in non-alcoholic fatty liver disease: beyond marrow cell mobilization

Protective effects of granulocyte colony stimulating factor (G-CSF) in acute liver injury via marrow cell mobilization have been reported in several studies. But exact mode of action and optimal protocol of G-CSF has been still doubt in chronic disease. Here we investigated mode of action and optimization of G-CSF as a treatment for non-alcoholic fatty liver disease (NAFLD). Various doses of conventional G-CSF (30 μg/kg once weekly, once daily for 5 days, twice weekly) and long acting G-CSF (30 μg/kg once a month) were evaluated in two kinds of NAFLD animal models to optimize the G-CSF protocol. G-CSF receptor expression highest increased in NAFLD model among various liver diseases compare to control (NAFLD: 14.7 times, alcohol hepatitis: 7.1 times, cirrhosis: 2.4 times, and ischemia reperfusion: 6.8 times). G-CSF treatment reduced intrahepatic fat accumulation, and inflammation in two kinds of NAFLD animal models. G-CSF increased PI3K/Akt expression in hepatocyte as well as decreased apoptotic drive (increased Bcl-2 expression and decreased Bax expression) in animal model. Five day consecutive G-CSF treatment and once a month long acting G-CSF increased marrow derived stem cell marker in peripheral blood. But twice a week conventional G-CSF treatment did not increased CD34+ cell in peripheral blood and liver neither. Not only high dose G-CSF (once daily for 5 days) but also hepatotropic dose G-CSF (twice a week) significantly reduced hepatocyte apoptosis via PI3K and Akt pathway activation without marrow cell mobilization in NAFLD animal model.