Figure 1
Characterization of placenta-derived cells. (A) Fibroblast colony-forming units (CFU-F) assay. Freshly isolated cells derived from (i) chorionic plate (cp) and (ii) chorionic villi (cv) were cultured in CFU-F forming conditions and stained with Giemsa. Black arrows indicate colonies. (B) The quantity of clones formed by cp-derived cells (78.5 ± 10.1) and cv-derived cells (31.4 ± 5.2) was compared (*P = 0.0015). (C) Karyotype analysis of cp- and cv-mesenchymal stem cells (MSCs) showing a 46, XY karyotype in both cases. (D) Flow cytometry analysis. Graph shows the percentage of positive cells for each surface marker in cp-MSCs (striped) and cv-MSCs (white). Expression of mesenchymal markers and adhesion molecules was high, while low expression of hematopoietic and endothelial markers was found. (E) Oil Red O staining after adipogenic differentiation. Cytoplasmic lipid droplets were observed in the induced (ii) cp-MSCs and (iv) cv-MSCs but were not present in the non-induced cultures (i and iii). White arrows indicate lipid droplets within the cytoplasm. (F) Alizarin Red staining after osteogenic differentiation. Calcium deposits in the extracellular matrix were observed in the induced (ii) cp-MSCs and (iv) cv-MSCs but were not present in the non-induced cultures (i and iii). Inserts in (E) and (F) show images in higher magnification. (G) Analysis of 3-week cultured pellets after chondrogenic differentiation. The micromass was stained with Alcian Blue. Nuclei were counterstained with Nuclear Fast Red. Proteoglycans, stained in blue, were observed in the induced (ii) cp-MSCs and (iv) cv-MSCs. Non-induced cultures (i and iii) did not present proteoglycan staining. (H) Quantitative reverse transcription-polymerase chain reaction (RT-PCR) array for cell cycle-related genes. Results are shown as fold changes in expression of cp-MSCs (stripped bars) when compared with cv-MSCs (white bar). All genes that were at least twofold up- or downregulated in cp-MSCs when compared with cv-MSCs are shown. Expression of BRCA2 and CCNF was significantly higher in cp-MSCs (*P <0.05).