Relationship between oxygen partial pressure and inhibition of cell aggregation of human adipose tissue-derived mesenchymal stem cells stored in cell preservation solutions

Introduction: This study investigated the storage conditions under which cell aggregation occurs and the conditions that inhibit cell aggregation when human adipose tissue-derived mesenchymal stem cells (hADSCs) are stored in lactated Ringer's solution (LR) supplemented with 3% trehalose and 5% dextran 40 (LR-3T-5D). Methods: We first examined the effects of storage temperature and time on the aggregation and viability of hADSCs stored in LR and LR-3T-5D. The cells were stored at 5 & DEG;C or 25 & DEG;C for various times up to 24 h. We then evaluated the effects of storage volume (250-2,000 mL), cell density (2.5-20 x 105 cells/mL), and nitrogen gas replacement on aggregation, oxygen partial pressure (pO2), and viability of hADSCs stored for 24 h at 25 & DEG;C in LR-3T-5D. Results: When stored in LR-3T-5D, viability did not change under either condition compared with prestorage, but the cell aggregation rate increased significantly with storage at 25 & DEG;C for 24 h (p<0.001). In LR, the aggregation rate did not change under either condition, but cell viability decreased significantly after 24 h at both 5 & DEG;C and 25 & DEG;C (p < 0.05). The cell aggregation rates and pO2 tended to decrease with increasing solution volume and cell density. Nitrogen gas replacement significantly decreased the cell aggregation rate and pO2 (p < 0.05). However, there were no differences in viability among cells stored under conditions of different storage volumes, densities, and nitrogen gas replacement. Conclusions: Aggregation of cells after storage at 25 & DEG;C in LR-3T-5D may be suppressed by increasing the storage volume and cell density as well as by incorporating nitrogen replacement, which lowers the pO2 in the solution. & COPY; 2023, The Japanese Society for Regenerative Medicine. Production and hosting by Elsevier B.V. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).

Automated summary

This study investigated the storage conditions that lead to cell aggregation and the conditions that inhibit cell aggregation when hADSCs are stored in LR-3T-5D. The results showed that storage temperature and time did not affect viability but significantly increased cell aggregation rate when stored at 25°C for 24 hours. Increasing solution volume and cell density, as well as nitrogen gas replacement, suppressed cell aggregation.