Figure 2. EC network formation and growth of EPCs in EC and EC+EPC models.

In the presence of bFGF, ECs formed a confluent monolayer on the gel (A) and invaded into the underlying gel (B). After 5 days in culture, ECs formed longer EC networks (C, arrowheads). EPCs embedded between double collagen gel layers gradually proliferated in culture (D: day 1, E: day 3, F: day 5). Scale bar, 100 μm.