Comparative studies of different cryopreservation methods for mesenchymal stem cells derived from human fetal liver.

Fetal stem cells possess some intriguing characteristics, which delineate them as promising cellular therapeutics. They are less immunogenic, at lower stage of differentiation and have higher potential for repopulation and migration. Furthermore, the fetal stem cells secrete a set of cytokines and growth factors, which stimulate the regeneration of the recipient tissue. The present study indicated that the adhesive fraction of human fetal liver cells possessed the morphological characteristics of mesenchymal stem cells, as well as potential to differentiate into adipocyte and osteoblast lineages. The immunophenotypic analysis showed that the cells expressed CD13, CD73, CD90 and CD105 (typical for mesenchymal stem cells) and lacked the haematopoietic lineage markers CD34 and CD45. Addressing the issue of the low-temperature storage of the human fetal liver cells, four different methods for cryopreservation were assessed: conventional slow freezing, program freezing and two vitrification protocols. The obtained results demonstrated that the cells were cryotolerant and maintained their properties and differentiation potential after thawing. Program freezing showed to be the most efficient method for cryopreservation of the investigated cells.