Third trimester amniotic fluid cells with the capacity to develop neural phenotypes and with heterogeneity among sub-populations

Purpose: Our aim was the search for new sources of cells potentially useful for central nervous system regenerative medicine. Extra-embryonic tissues are promising sources of pluripotent stem cells. Among these, human second-trimester amniotic fluid (AF) contains cell populations exhibiting self-renewal capacity, multipotency and the expression of embryonic cell markers. Methods: Here we report the properties of the easily available third-trimester AF cells (AFCs). Different cell types from 6 of 9 AF samples were separated, expanded, and characterized by assessing their morphological, proliferative, and differentiative properties. Results: All isolated cultures presented CD105, CD90 and CD73 mesenchymal markers, whereas they differed among themselves in CD117, CD146, CD31, NG2 and CD133 expression. Their doubling time and telomere length were conserved throughout many passages. Importantly, immunofluorescence and Real-time PCR showed that, during their proliferative state and differentiation, several cultures expressed neuronal and glial markers such as nestin, GFAP, beta-tubulin III and neurofilament H indicating their potential attitude towards a neural fate. Indeed, these cells showed a rather poor capacity to differentiate in adipogenic and osteogenic lineages. Conclusions: In this work we report that cells with neural differentiation capability can be isolated from third-trimester AF, such properties could be useful for neuro-regenerative purposes.