Chromosomal characterization of cryopreserved mesenchymal stem cells from the human subendothelium umbilical cord vein

Abstract

Aims: To conduct a morphological, functional and chromosomal characterization of mesenchymal stem cell populations from the human subendothelium umbilical cord vein after cryopreservation. Material & methods: Five human umbilical cords were processed in order to obtain mesenchymal stem cells. Flow cytometry, differentiation assays and cytogenetic analysis were carried out before and after the cryopreservation process. Results: Flow cytometry revealed that CD105, CD73 and CD90 markers were expressed by the cells, which lacked the expression of hematopoietic lineage markers, such as CD14, CD34 and CD45. The mesenchymal stem cells demonstrated capacity for osteogenic, adipogenic and chondrogenic differentiation. Chromosome analysis showed no clonal chromosome changes in the cells in either situation. However, a significant number of nonclonal chromosomal aberrations were apparent after cryopreservation, including monosomies and structural changes. Cells isolated from one umbilical cord exhibited a rare balanced paracentric inversion, likely a cytogenetic constitutional alteration. This was present both before and after experimental procedures. Conclusion: These findings show that using mesenchymal stem cells for clinical approaches requires careful investigation and sensitive tests in order to ensure cellular therapy biosafety.