Effects of storage solutions on the viability of human umbilical cord mesenchymal stem cells for transplantation.

Human umbilical cord-derived mesenchymal stem cell (UC-MSC) transplantation has shown promise for the treatment of various diseases. For clinical applications, UC-MSCs have been stored in 0.9% saline, 5% dextrose, dextrose and sodium chloride injection, Plasma-Lyte A, 1% human serum albumin (1% HSA), or 5% HSA before administration, but the effect of storage conditions on the viability and biological function of the cells remains unknown. Freshly harvested UC-MSCs were resuspended and incubated in these solutions for 2, 4, or 6 h at 4°C or room temperature (24°C). Cell viability, apoptotic/necrotic fraction, poststorage growth potential, immunophenotype, immunosuppressive capacity, and differentiation capacity were analyzed. When stored in parenteral solutions, UC-MSCs showed progressive deterioration in survival viability and adhesion ability. After 6-h storage, the best viability and attachment rate of UC-MSCs decreased to 83.0 ± 1.6% and 71.8 ± 3.2%, respectively. Our results suggested that UC-MSCs in these conditions lose their viability in a short time. However, it seems that the other biological functions of the surviving UC-MSCs were little affected. Since UC-MSCs suspended in these mediums lose their survival viability in a short time to levels significantly below the permissible limits (70%) by FDA, precautions need to be taken on using these solutions as suspension medium and further studies on the optimal methods for preservation are urgent.