Figure 4

Proliferation potential of human umbilical vein endothelial cells (HUVEC). Significant morphological differences were not observed for A) fresh cultivated and B) cryopreserved HUVEC. C) Proliferation potential of recultivated short-term (group A, n = 4) and long-term (group B, n = 5) cryopreserved cells was quantified using a colorimetric WST-1 assay (C). By comparison, non- cryopreserved fresh cells (n = 4) were analyzed in parallel as a control group. The optical density (OD) was measured at 450 nm and reference wavelength of 630 nm was subtracted. OD values were correlated to the number of living cells and the higher OD values meant a higher cell number. Morphology and proliferation potential are exemplarily shown for cells of passage 3.