1 School of Medicine , Tsinghua University , Beijing , China.
2 Division of Experimental Pathology, Department of Pathology , University of Pittsburgh School of Medicine , Pittsburgh , Pennsylvania , USA.
3 Pittsburgh Liver Research Center , University of Pittsburgh Medical Center and University of Pittsburgh School of Medicine , Pittsburgh , Pennsylvania , USA.
4 Division of Gastroenterology, Hepatology and Nutrition, Department of Medicine , University of Pittsburgh School of Medicine , Pittsburgh , Pennsylvania , USA.