Fig. 2.

Incubation of EBs with RA and cAMP induces LYVE-1 expression in CD31+ vessel-like structures. Differential immunofluorescence analysis of control EBs for expression of CD31 and LYVE-1 showed the formation of CD31+/LYVE-1– blood vessel-like structures, whereas only a few endothelial cells expressed LYVE-1 (a–c). Incubation with RA induced LYVE-1 expression in the CD31+ structures (d–f). RA in combination with cAMP (RA + cAMP) further increased the CD31+/LYVE-1+ area (g–p). The total CD31+ and the CD31+/LYVE-1+ area, but not the CD31+/LYVE-1– area was increased (p). Data are expressed as mean values + SEM (n = 9). Scale bars = 100 μm.