Abstract
Background aims
Because of their ability to differentiate and widespread availability, human mesenchymal stromal cells (hMSC) are often used as a clinical therapeutic tool. However, the factors that determine the quality and viability of hMSC are not well understood.
Methods
We evaluated the viability of hMSC over time using flow cytometry analysis (FACS) and transmission electron microscopy (TEM) to determine if morphologic changes occurred in hMSC. In addition, we conducted gene expression prof ling using an Affymetrix Human Genome U133 Plus 2.0 Array.
Results
FACS analysis revealed that 83% and 76% of the cells were viable in sterilized phosphate-buffered saline (PBS) after 6 h and 12 h, respectively.
TEM data revealed that the total number of cells with healthy chromatins or a few cytosolic vacuoles was significantly reduced over time. We then conducted gene expression prof ling using a microarray, which revealed changes in the expression of 2949 functional genes. Specifcally, among the total of 50 000 gene probes evaluated, the expression levels of apoptosis and stress-related genes were significantly increased over time.
Conclusions
The results of this study suggest that the viability of hMSC decreases after disassociation from the culture dish and time is an essential factor when considering hMSC as a potential source for stem cell-based direct transplantation.
Acknowledgements
This work was supported by the Korea Research Foundation Grant funded by the Korean Government (MOEHRD, Basic Research Promotion Fund; KRF-2007–313-H00012) to Gwang Lee, and partly supported by a Korea Science and Engineering Foundation (KOSEF) grant funded by the Korean Government (MOST; R01–2007–000–20533–0) to Sangdun Choi.
Declaration of interest: The authors report no conflicts of interest. The authors alone are responsible for the content and writing of the paper.