RESUMO
The placenta is an attractive new source of mesenchymal stem cells (MSCs), but the biological characteristics of placenta-derived MSCs (P-MSCs) have not yet been characterized. We successfully isolated, cultured and expanded P-MSCs using routine methods. Under appropriate induction conditions, these cells can differentiate into bone, cartilage, fat and hepatocyte-like cells. In addition, the proliferative response of P-MSCs to different cytokines was monitored using the MTT assay. The results show that low concentrations of proinflammatory cytokines, e.g. RANTES, interleukin (IL)-1, IL-6 and IL-8 can stimulate the proliferation of P-MSCs in a dose-dependent manner, peaking at concentrations of 40 ng/ml of RANTES, 10 ng/ml of IL-1 and IL-6, and 150 ng/ml of IL-8 (p < 0.01). The level of proliferation decreased when the concentration of these four cytokines increased beyond these values. On the other hand, anti-inflammatory cytokines hepatocyte growth factor and IL-4 had an inhibitory effect on P-MSCs. In conclusion, the placenta contains MSCs that are consistent with the characteristics of bone marrow MSCs. Low concentrations of proinflammatory chemokines stimulated the proliferation of P-MSCs while anti-inflammatory cytokines inhibited the growth of P-MSCs in a dose-dependent manner.
