Placenta-Derived Cells and Their Therapeutic Applications

The human placenta serves as a medium of exchange of oxygen, nutrients, and waste products between the mother and the fetus. This foetomaternal organ provides the most intimate connection between the fetal and maternal tissues. The placental tissues originate very early during embryogenesis, prior to gastrulation, suggesting that they may harbor cells that retain some stem/progenitor cell potential with the ability to differentiate toward different cell lineages. Furthermore, placenta plays an essential role in maintaining fetomaternal tolerance during pregnancy, indicating that placental cells may have special immunomodulatory properties and, finally, placenta can be easily procured after delivery and its use is free from ethical concern. An understanding of the structure of the placenta, described in detail later, will be of help in the identification of the varied cell types that can be isolated from its specific regions.