The Role of Mesenchymal Stem Cells in the Functions and Pathologies of the Human Placenta

The proper function of the human placenta is essential for all stages of pregnancy and for the successful outcome of a healthy baby. Nurturing the fetus and removing fetal waste products require the placenta to carry out a wide range of functions. The increasing demands on the placenta to support the rapidly growing fetal placenta are met by establishing and maintaining an interface with the mother’s uterus and under- lying tissues, and by modifying vessels in the maternal circulation to increase blood flow to the placenta. Given the complex morphological and physiological changes that occur in the placenta during its formation, and the varied functions that the placenta performs, it is not surprising that disruption of these processes results in significant placental pathologies. Clinically, the most important of these pathologies is the hyper- tensive disorder preeclampsia (PE). Despite the placenta’s complex and critical roles, there are major gaps in our understanding of the biology and molecular mechanisms involved in normal and pathological placental development. Here, we highlight recent studies providing evidence for stem cells as important new players in the formation of the placenta, the establishment of the fetal-maternal interface, and the pathology of PE.