Development of an infusible-grade solution for non-cryopreserved hematopoietic cell storage

Background: Various tissue culture medium formulations currently are used to transport, store and process stem and progenitor cells for transplantation, although these solutions are not manufactured for clinical use. Methods: We have developed an infusible-grade solution, STM-Sav, for short-term liquid cell storage and tested its ability to maintain viable functional hematopoietic cells, compared with commonly-used tissue culture solutions. G-CSF-stimulated normal-donor PBPC were stored in α-MEM, IMDM, RPMI-1640, AIM 5, X-VIVO 10, PlasmaLyte A and STM-Sav, in gas-permeable Cryocyte bags, at ambient temperature and 4°C. The percentage of viable cells, percent recovery of viable mononuclear cells (MNC), percentage of CD34⁺ cells, CFU-GM frequency and solution pH were determined for each solution, at time points ranging from 0 to 72 h. Results: Cells were slightly better maintained at 4°C than at ambient temperature. No solution was superior to any other overall, although PlasmaLyte A was significantly inferior to all other solutions at preserving viable MNC. STM-Sav consistently maintained viable, functional cells as well as, or better than in-vitro-use-only culture media, or PlasmaLyte A. Discussion: Cells could be stored in STM-Sav for at least 24 h at 4°C or ambient temperature, with recovery of approximately 90% of initial viable MNC, unchanged percentage CD34⁺ cells and stable solution pH.