Figure 5.

BSN-CM maintains UB cell morphogenesis better than any other purified growth factor or their combination. Purified growth factors, a combination of growth factors (GF-mix: HGF, EGF, bFGF, IGF-1, and GDNF), or BSN-CM was applied on top of UB cells suspended in collagen gels. Tubulogenic activity was semiquantified by evaluating percentage of UB cells/colonies with processes/cords/tubules. At 24 hr of serum-free culture, HGF, EGF, TGF-α, bFGF, and IGF-1 were as capable of inducing UB cell processes as were GF-mix or BSN-CM medium. TGF-β1, PDGF, and GDNF were not effective. At 5 days of culture (with 1% serum), only high concentrations of bFGF and IGF-1 could sustain the growth of UB cell processes into cord-like structures. BSN-CM was much more potent than any other growth factors listed or their combination. Statistical significance was determined and is presented in Table 1, where a qualitative analysis of structures is also presented.