Properties and clinical application of human amniotic epithelial cells (HAEC)
Arkadiusz Gawryluk1, Bartłomiej Noszczyk2
In the contemporary medicine, undifferentiated progenitor cells of various origin and various degree of plasticity have become highly promising. Their most abundant, renewable and uncontroversial sources are placental tissues and umbilical blood. The only epithelial cells in this group come from the amnion which is used as a whole as an allogenic biological dressing. They have a range of unusual properties, such as the relative lack of histocompatibility antigens, plasticity (enabling their differentiation into a number of epithelial and mesenchymal cells) and the lack of neoplastic capacity. Amniotic epithelial cells are the only epithelial cells of the placenta. It is believed that they retain their progenitor (pluripotent) properties even in term pregnancies. This probably results from the fact that they omit the differentiation that accompanies gastrulation. Such features are typical of all placental cells which differ from amniotic epithelial cells only in their non-epithelial origin. In culture conditions, amniotic epithelial cells are characterized by a considerable plasticity: they can be stimulated to differentiate into adipocytes, chondrocytes, osteocytes, myocytes, cardiomyocytes, neurocytes, pancreatic cells and hepatocytes. To date, however, the attempts to direct their development towards the epidermis have not been successful. Obtaining multilayer epidermis in amniotic epithelial culture would be of considerable importance for tissue engineering of biological dressings. Amniotic membranes have been used for this purpose for many years, but because of their complex structure and metabolic requirements, they do not heal but dry up when applied to the wound. Some reports, however, indicate that the epithelium isolated from the amnion could be able to heal thus being suitable for allogenic grafts.