ABSTRACT
@#Amniotic fluid (AF) holds many important roles in the development of the fetus such as supporting fetal growth as well as protecting it from distress or infection. The fluid can also function as a vital source of fetal cells to be used in prenatal assessment of the fetus. Should it not be used or requested to be used by the patient, it will be discarded. There are numerous reports in the literature on the various cells present in amniotic fluid; as the population of cells is heterogeneous with a diverse range of cells, to include differentiated and undifferentiated cells. </br> Although AF cells were reported to have limited proliferative capacity and are terminally differentiated cells, telomerase activity was detected in both cultured and uncultured human AF cells from 14 weeks’ gestation, suggesting that cells with high proliferative capacity exist in AF. Populations of stem cells in AF are based on their potency, either multipotent or pluripotent. There are 2 types of multipotent AF cells discovered; the amniotic fluid c-Kit+, Lin- (AFKL) cells and amniotic fluid mesenchymal stem cells (AF-MSCs). AFKL are multipotent AF cells having multilineage hematopoetic potential in vitro and express CD4. Furthermore, expression of Oct4 (critical marker for pluripotency) was also discovered, indicating the presence of a pluripotent subpopulation of cells in AF-stem cells. Most importantly, the discovery of stem cells in AF, specifically Amniotic Fluid Stem Cells (AFSC), has elevated the potential of AF as AFSC signify a novel class of pluripotent stem cells with intermediate characteristics of ES cells and adult stem cells. </br> AFSC are easy to maintain in the laboratory, the proliferation and differentiation of AFSC is both safer and more ethical to use in clinical applications as they are non-tumorigenic and relatively accessible, being acquired using a minimally invasive procedure. Furthermore, AFSC would be an ideal candidate for autologous transplantation as they lack the MHC Class II antigen and are therefore non-immunogenic. These advantages present an interesting application for AFSC in future in vitro and in vivo studies. </br> In this review, we have summarized some of the important aspects of AF and AFSC and provided an update on those cells present in AF, together with its future potential for prenatal assessment. Consequently, amniotic fluid represents a very valuable tool that has the potential to save lives and reduce human suffering, particularly through regenerative medicine.