Human term placental cells: phenotype, properties and new avenues in regenerative medicine.

The human placenta has long been the subject of scientific interest due to the important roles which it performs during pregnancy in sustaining the fetus and maintaining fetomaternal tolerance. More recently, however, researchers have begun to investigate the possibility that the placenta's utility may extend beyond fetal development to act as a source of cells with clinically relevant properties. Indeed, several groups have reported the isolation of cells from different placental regions which display both multilineage differentiation potential and immunomodulatory properties in vitro. Furthermore, these cells have also been shown to secrete soluble factors involved in pathophysiological processes that may aid tissue repair. Cells with such features will clearly find application in the field of regenerative medicine for the repair/regeneration of damaged or diseased tissues or organs. In line with these promising findings, several preclinical and clinical studies conducted to date argue in strong favor of the therapeutic utility of placenta-derived cells for the treatment of several diseases. Although much work remains to be conducted in order to fully understand the properties of placental cells and the mechanisms which underlie their beneficial effects in vivo, data reported to date nonetheless provide compelling evidence in support of the placenta as a cell source for use in regenerative medicine.