Cryopreservation and revival of mesenchymal stromal cells

Over the past few years, the pace of preclinical stem cell research is astonishing and adult stem cells have become the subject of intense research. Due to the presence of promising supporting preclinical data, human clinical trials for stem cell regenerative treatment of various diseases have been initiated. As there has been a precedent for the use of bone marrow stem cells in the treatment of hematological malignancies and ischemic heart diseases through randomized clinical safety and efficacy trials, the development of new therapies based on culture-expanded human mesenchymal stromal cells (MSCs) opens up new possibilities for cell therapy. To facilitate these applications, cryopreservation and long-term storage of MSCs becomes an absolute necessity. As a result, optimization of this cryopreservation protocol is absolutely critical. The major challenge during cellular cryopreservation is the lethality associated with the cooling and thawing processes. The major objective is to minimize damage to cells during low temperature freezing and storage and the use of a suitable cryoprotectant. The detrimental effects of cellular cryopreservation can be minimized by controlling the cooling rate, using better cryoprotective agents, maintaining appropriate storage temperatures, and controlling the cell thawing rate. As is described in this chapter, human MSCs can either be frozen in cryovials or in freezing bags together with cryopreserve solutions containing dimethyl sulfoxide (DMSO).