Noncryopreserved bone marrow storage in STM-Sav, an infusible-grade cell storage solution

Liquid storage of hematopoietic stem and progenitor cells often is necessary in clinical cell engineering. The interval between cell harvest and transplantation or processing may be as long as 1 or 2 days. We previously developed an infusible-grade solution, STM-Sav, for nonfrozen storage of peripheral blood stem cells. This study addresses the validation of the storage conditions using STM-Sav for the short-term storage of bone marrow. Bone marrow from normal donors was stored in STM-Sav in gas-permeable Cryocyte and plasma transfer bags at 4°C and room temperature. Cell viability, number, and morphology, percentage of CD34⁺ cells, frequency of granulocyte/macrophage colony-forming units (CFU-GM), and solution pH were measured every 24 h for up to 72 h. More than 88% of viable nucleated cell recovery was observed at 72 h of liquid storage. CD34⁺ cell recoveries were unchanged over the 72-h storage period as well, and the frequency of CFU-GM per 10⁵ cells was also constant. The regulation of solution pH was improved with storage of the cells at 4°C in a plasma transfer bag. These results indicate that STM-Sav can be effective in preserving bone marrow viability over a 72-h period during liquid storage.