Effects of cryopreservation conditions on human adipose-derived mesenchymal stem cells and its potential application in cardiac fibrosis / Yong Kar Wey

Human adipose-derived mesenchymal stem cells (hASCs) hold great potential for clinical application (e.g., regenerative medicine and cell-based therapies) due to their multilineage differentiation ability and paracrine function. To achieve sufficient numbers of hASCs for off-the-shelf-use in an intensive clinical setting (e.g., cardiac fibrosis therapy), hASCs at early passage should be capable of being cryopreserved in the long-term with cell functionality maintained without raising biosafety concerns (e.g., tumourigenesis). The objectives of this study are to evaluate the effects of cryopreservation conditions on hASCs and the potential application of cryopreserved hASCs in cardiac fibrosis. In this study, hASCs were cryopreserved for 3 months using a slow freezing method in various combinations of 3 general used cryoprotective agents (CPAs), including dimethylsulfoxide (DMSO), trehalose, and fetal bovine serum (FBS). Following rapid thawing, hASCs cryopreserved in a cryopreservation medium containing DMSO at a reduced concentration without FBS (5% DMSO) were found to maintain high viability and functional properties in terms of differentiation potential (including adipogenic, osteogenic and chondrogenic), proliferation potential, and stemness. Moreover, hASCs cryopreserved in 5% DMSO have a low risk of tumourigenesis, as indicated by normal expression levels of tumour suppressor markers and human telomerase reverse transcriptase (hTERT), normal telomere length, and normal telomerase activity without significant DNA damage or p53 mutation. In addition, it was found that fresh (non-cryopreserved) hASCs and hASCs cryopreserved in 5% DMSO both display a similar potential to inhibit cardiac myofibroblast differentiation in vitro via paracrine signalling, and thus may decrease the incidence of cardiac fibrosis. In summary, 5% DMSO without FBS may be an ideal CPA for efficient long-term cryopreservation of iv hASCs for clinical applications. Further, long-term cryopreserved hASCs demonstrate their significant therapeutic value in cardiac fibrosis therapy