Human term placenta as a therapeutic agent: from the first clinical applications to future perspectives

The placenta is a fetomaternal organ provided by nature to aid development of the growing embryo by facilitating gas and nutrient exchange between the mother and fetus and by helping to maintain fetomaternal tolerance. Aside from playing an age-old and essential role in fetal development, placental tissues have also attracted the interest of clinical scientists due to their potential utility as a therapeutic agent. For decades, the human term placenta, which is available in plentiful supply and raises no ethical concerns for its procurement, has been used as a surgical material in skin transplantations, as a biological dressing for treatment of skin wounds, burn injuries and chronic leg ulcers, for prevention of tissue adhesion in surgical procedures, and in ocular surface reconstruction. More recently, human placenta has also attracted increasing attention from cell and molecular biologists who have turned to this tissue in the search for a novel stem cell source. Indeed, cells derived from the amniotic and chorionic fetal membranes have been shown to present with high plasticity and to possess low immunogenicity as well as immunomodulatory properties, thereby making them prime candidates for development of cell therapy-based tissue regeneration strategies. This chapter will provide an overview of the clinical applications which have been described for placental tissue or are currently applied, as well a summary of the most recent results obtained in preclinical studies, which present promising perspectives for the future clinical application of these cells.