Fig. 3

AFS cell morphology and behavior in culture. a AFS cells from both trimesters were expanded in normoxic (20 % O₂) or hypoxic (5 % O₂) conditions maintaining sub-confluence between passages (scale bar = 200 μm). b For each type of sample and culture condition, the cell cycle phases (G₀-G₁, S and G₂-M) were quantified by flow cytometry after propidium iodide staining of the cells (left graphs). Cells in well were counted at different time points to obtain a growth curve (central graphs) and were expressed by population doublings at each measured point (n = 5). From the growth curve, the mean doubling time (right graphs) for each condition was calculated and compared to see whether hypoxia was influencing the time window of cell replication. c Endothelial transcription factor detection: ETV2, FLI1 and VEGFA were expressed at basal level in AFS cells. *P < 0.05, ***P < 0.001. CB was used as positive control for ETV2 expression, whereas the adult HUVECs were used as positive control for the other two genes (white bars); 20 % O₂ condition represented by red bars and lines; 5 % O₂ condition represented by blue bars and lines. AFS amniotic fluid stem, A.U. arbitrary units, CB cord blood, HUVEC human umbilical vein endothelial cell