IGF1 and tuberous sclerosis: For instance, Liu et al., reported that a combined treatment of IGF-1 and BMP-2 on rat TSPCs significantly increased adipogenic differentiation through a prostaglandin E (PGE) 2-mediated pathway [422] while Holladay et al. [387] reported that in vitro IGF-1 treatment alone promoted the proliferation and maintenance of TSC phenotypes, leading to a slight increase in Scx, no influence on Col I, and a downregulation of Col II expression [387].