The biological characteristics of human third trimester amniotic fluid stem cells.

Third trimester amniotic fluid (AF)-derived human mesenchymal stem cells (MSCs) can be greatly expanded in vitro and induced to differentiate into multiple mesenchymal cell types. This study aimed to investigate the biological characteristics of MSCs from third trimester AF as a new source of therapeutic stem cells. Forty third trimester AF samples were obtained from healthy women who underwent elective caesarean section for breech presentation. A simple culture protocol for MSCs was used. A cell growth curve was drawn, and cell surface antigens and cytokines were analysed by immunofluorescent staining, reverse transcription-polymerase chain reaction and flow cytometry. MSCs from third-trimester AF were successfully isolated, cultured and enriched. MSCs expanded extensively without feeders, they were not tumourigenic and were induced to differentiate into osteocytes. Surface antigens were analysed and found to express the pluripotency marker Oct-4. Considering the great feasibility of biomedical engineering using MSCs, third trimester AF may provide a rich source for investigation of human MSCs.