- Peroxisome proliferator-activated receptor-beta signaling contributes to enhanced proliferation of hepatic stellate cells. Hellemans, K., Michalik, L., Dittie, A., Knorr, A., Rombouts, K., De Jong, J., Heirman, C., Quartier, E., Schuit, F., Wahli, W., Geerts, A. Gastroenterology (2003)