Refrigerated human mesenchymal stromal cells as an alternative to cryostorage for use in clinical investigation

Background: Mesenchymal stromal cells (MSCs) and other therapeutic cells show efficacy for cardiac damage, neurological disease, chronic lung disease, pediatric graft versus host disease, and several inflammatory conditions. Based on their anti-inflammatory and immune-modulatory activities, responsiveness, and secretion of beneficial factors, cellular therapeutics may provide benefits in acute and chronic traumatic injury. However, the use of live cells presents logistical challenges, especially for military trauma. MSCs are generally shipped and stored frozen but require sterile handling before infusion. This requires skilled personnel and equipment not readily available in a forward medical treatment facility or even a small community hospital. Methods: Commercial human bone marrow- and adipose-derived MSCs from multiple donors were cultured under standard conditions, harvested and stored at 4°C in solution for up to 21 days. Cell viability, ATP content, apoptosis, proliferation capability, immunomodulation activity, and responsiveness were assessed after different amounts of time. Results: Human MSCs can be stored at 4°C in MSC culture medium for 14 days while maintaining a reasonable level of viability and function. Both viability and function are reduced when MSCs are stored in crystalloid solutions. Conclusions: This approach makes it feasible to prepare cellular therapeutic agents in a laboratory or commercial facility and ship them under refrigerated conditions. Once they reach their destination, they can be stored at 4°C under conditions similar to blood products. Cells prepared and stored this way could also be used directly with minimal handling, making them more practical for both civilian and military trauma.