Growth and identification of human amniotic fluid stem cells and analysis of their influencing factors

Amniotic fluid stem (AFS) cells derived from human amniotic fluid were cultured in vitro and the factors of affecting the primary culture of human AFS cells were investigated. The isolated AFS cells, which express embryonic stem cell markers, such as Oct-4, and adult stem cell markers, such as CD29, grew faster and had high proliferation ability. Moreover, AFS cells could differentiate into neurons and cardiomyocytes which expressed Nestin and α-actin, respectively. There were several factors, such as the date of gestation, the level of blood contamination and the volume of amniotic fluid, could significantly affect the attachment time and numbers of AFS cells in the primary culture. The results showed that cell attachment time of the 2nd trimester of gestation (4.7±0.6) d was significantly different from that of the 3rd trimester of gestation (6±0.5) d (P 0.05), suggesting that cells collected from the fluid of 3rd trimester of gestation needed longer attachment time. Blood contamination could significantly affect the cell attachment time. The attachment time of brown-color fluid group (10.8±0.3) d was significantly different with the blood-cell-free fluid group (6±0.5) d and blood-cell group (6.3±0.6) d (P 0.05). The volume of amniotic fluid influenced on cell attachment numbers and time to some extent. With the increase of amniotic fluid volume, cell attachment numbers significantly increased (P 0.05), and cell attachment time extended but no significant difference(P 0.05). The present studies systematically examined the factors, effection on primary culture of human AFS cells and provided some useful data for AFS cell research. Additionally, the isolated AFS cells maintain the capabilities of differentiation into other cell types and are able to become seed cells for the clinical application.