Effect of Storage Conditions on the Integrity of Human Umbilical Cord Mesenchymal Stromal Cell-Derived Microvesicles

Abstract

We studied the effect of storage conditions on the safety of microvesicles produced by human multipotent umbilical cord mesenchymal stromal cells into the conditioned medium. It was found that microvesicles can be stored without serious degradation for up to 1 week at 4°С, but were almost completely destroyed during freezing and thawing cycles irrespective of the storage temperatures (-20°С, -70°С, or -196°С). Similar results were obtained for lyophilized medium conditioned by human multipotent umbilical cord mesenchymal stromal cells. Addition of a cryoprotectant (5-10% DMSO) followed by freezing and/or lyophilization preserved microvesicles at a nearly initial level. These findings indicate that during storage, microvesicles, being membrane structures, behave similar to living cells and require appropriate conditions for prolonged storage.