Is stem cell chromosomal stability affected by cryopreservation conditions?

The use of in vitro cultured stem cells in cell therapy, must meet at least two requirements: the preservation of a normal genetic karyotype and maintenance of integrity during long term-culturing and storage in liquid nitrogen tanks. Here we report on the karyological characterization of neural stem cells derived from adult (ANS) subentricular zone (SVZ), mouse fetal cotex cells, mESCs cells NS46 (LC-1) and related engineered clones as well as Neurospheres from the mouse striatum Li-4. The results show a series of chromosomal aberrations present in these cells in agreement with previous reports. On the other hand, karyotyping of the human neural stem cell lines derived from hESCs (H9-hNCPC) and fetal cerebellum (CB541) showed a stable genomic asset with few chromosomal aberration. These results underscore the importance of performing routine cytogenetic analysis before using the cells to produce chimeric mice or in studies of lineage specific differentiation. We are also evaluating the use of Cell microarray for high-throughput screening of stem cell differentiation by immunocytochemical analysis. With this technique we were able to follow the expression of neural differentiation markers and the involvement of SEL1L gene in stem cell self-renewal.