Isolation and characterization of human cKIT positive amniotic fluid stem cells obtained from pregnancies with spina bifida.

Myelomeningocele (MMC) and myeloschisis (MS) are considered as the most severe forms of spina bifida aperta characterized by incomplete closure of the neural tube during the first trimester of pregnancy. Open maternal-fetal surgery has been identified as a promising alternative for the repair of MMC/MS. The main goal of this study was the isolation and characterization of stem cells derived from MMC/MS amniotic fluid samples. Human amniotic fluid samples were obtained from pregnant women who underwent surgery for fetal spina bifida repair. We applied fluorescence activated-cell sorting (FACS) to immunoselect stem cells from heterogeneous populations of amniocytes based on cKIT (CD117) expression. The cKIT(+) amniocytes were then contrasted with cKIT(-) and unselected amniocytes in order to characterize the phenotype of these cells. cKIT-expressing amniocytes exhibited spindle-shape morphology, while amniocytes negative for cKIT were round-shaped. qRT-PCR analysis revealed significant upregulation of mean mRNA levels of KIT and CD90 genes and downregulation of CK8 gene in cKIT-expressing amniocytes, compared to the negative and unsorted cells. The expression of pluripotency antigens was comparable in sorted cKIT(+) and cKIT(-) amniocytes and in unselected cells. Our results are of pivotal importance for the future application of amniotic fluid derived stem cells in spina bidfida repair.