Background: Marrow stromal cells (MSCs) for clinical trials are inevitably stored before administration, but little is known about the effects of storage on MSCs. The effects of short-term liquid storage on the in vitro function of MSCs intended for a clinical trial were studied.
Study design and methods: Early-passage human MSCs were suspended in 0.9% saline or culture medium and stored at 4 degrees C or room temperature for up to 72 hours followed by assessment of cell loss, viability, and growth in culture.
Results: When stored in saline at 4 degrees C, MSC counts decreased by 5% to 20%, MSC viability decreased 17% to 37%, and MSC growth decreased 65% to 100% after 24-hour storage. Similar results were obtained by MSC storage at room temperature or in Dulbecco's modified Eagle's medium or by addition of 1% human serum albumin (HSA) from two manufacturers. Storage of MSCs in saline with HSA from a third manufacturer maintained MSC viability at prestorage levels and improved poststorage MSC growth versus saline (32 +/- 9% vs. 9 +/- 9%; p < 0.05) or saline with two other HSA preparations (4 +/- 4 and 8 +/- 11%; p < 0.05).
Conclusion: MSCs stored at 4 degrees C or room temperature, in saline or culture medium, rapidly become nonviable. HSA preparations vary significantly in their ability to maintain poststorage MSC viability and growth. These results provide insight regarding the effects of storage on MSCs and indicate the need to screen HSA preparations before their use as additives to preserve MSCs during short-term liquid storage.