Fig. 4

Effect of medium supplements on established vascular networks. Fibrin matrices containing HUVEC and ASC were cultured for 4 days in full medium. Afterwards, co-culture in fibrin scaffolds was either continued in full medium or switched to basal medium. No aprotinin was added. a Cells in fibrin clots cultured exclusively in full medium formed vascular networks within 4 days and the vascular structures persist over 21 days. In samples that were switched to basal medium, degradation of the fibrin matrix could be observed on day 14. No difference in vascular network density was visible on day 4 before the switch occurred. b Quantification of network formation. Co-cultures displayed similar vascular network values until the switch from full to basal medium. Co-culture in basal medium results in significantly less junctions, tubules, decreased total tubule length and increased mean tubule length compared to full medium samples on day 7. Values are from two independent experiments using two different ASC donors; n = 9; ***p < 0.001; ns not significant. Scale bar: 200 μm