Trehalose: effect on cryopreservation of umbilical cord blood-derived hematopoietic stem cells

Abstract

Introduction: Concerns over dimethyl sulfoxide (DMSO) toxicity, related to adverse reactions after hematopoietic stem cells (HSCs) therapy, warrant the development of an optimized DMSO-free or DMSO-reduced cryopreservation protocol for the quality and safety of HSCs. In this regard, the ideal concentration of trehalose, as a non-toxic natural cryoprotectant, is still an area of research. Based on the outcome of our previous study on lower concentrations of trehalose, the present study was focused on evaluating its cryoprotective efficacy at an increased concentration (0.5 M) on HSCs compared to 10% DMSO. This is a laboratory-based experimental study. Material and methods: The separated mononuclear cells collected from umbilical cord blood were set for culture up to two passages to get HSCs. The two different concentrations of trehalose, with and without 5% DMSO, were considered as freezing media for the preservation of the harvested HSCs in a slow freezing set up. Two sequential functional assays, viability followed by hematopoietic colony-forming unit assay, were performed with post-thawed cells of freezing media used in this study. Seventeen cord blood samples were selected. Results: Study results revealed 0.5 M trehalose and DMSO 5% showed the highest viability of 91.8 ±2.8% of HSCs. 5% DMSO inclusion to trehalose (0.5 M) ameliorated hematopoietic colonies such as erythroid and myeloid colonies with no significant difference from that of 10% DMSO. Conclusion: 0.5 M trehalose has proved to be a better concentration than 10% DMSO alone. This experimental study needs further transplantation-based clinical trials using post-thawed cells to ensure the safety of preserved HSCs from cord blood and other sources.