[1] The presence of embryonic and foetal cells from all germ layers in the amniotic fluid was gradually determined since the 1980s.
Haematopoietic progenitor cells were first reported to be present in the amniotic fluid in 1993, specifically up to the 12th week of pregnancy.
[1] The majority of stem cells present in the amniotic fluid share many characteristics, which suggests they may have a common origin.
[6] However, foetal stem cells attained from the amniotic fluid are more stable and more plastic than their adult counterparts making it easier for them to be reprogrammed to a pluripotent state.
[6] Mesenchymal stem cells (MSCs) are highly abundant in the amniotic fluid and several techniques have been described for their isolation.
They usually involve the removal of amniotic fluid by amniocentesis and their distinction from other cells may be based on their morphology or other characteristics.
Originally it was proposed that the MSCs were discarded from the embryo at the end of their life cycle but since the cells remained viable in the amniotic fluid and were able to proliferate in culture this hypothesis was overturned.
[9][3] Possible applications include the use of amniotic stem cells for foetal tissue engineering to reconstruct birth defects in infants.
A small amount of amniotic fluid provides a large enough quantity of cells for the tissue engineering process and could help correct a number of defects including diaphragmatic hernia and possibly repair premature membrane rupture during pregnancy.
Several strategies have been tested in rats including the injection of dissociated amniotic stem cells into the infarct region, which yielded conflicting results from several research groups.
[13] Moreover, other findings have brought the proof of concept that secretome of amniotic stem cell could act as an effective paracrine agent against Doxorubicin induced cardiotoxicity,[14] confirming the potential importance of this cellular population in the field of cardiological research.
This was shown in mouse models for Alport syndrome, where the cells prolonged survival of the animals by slowing down the progression of the disease.
[17] The same effect was observed in mouse models where human amniotic stem cells were used to treat uretral obstruction.