SUL-109 protects hematopoietic stem cells from apoptosis induced by short-term hypothermic preservation and maintains their engraftment potential

Abstract The newly developed 6-hydroxychromanol SUL-109 was shown to provide protection during hypothermic storage of several cell lines, but has not been evaluated in hematopoietic stem cells (HSCs). Hypothermic preservation of HSCs would be preferred over short-term cryopreservation to prevent cell loss during freezing/thawing and be particularly useful for short-term storage, e.g., during conditioning of patients or transport of HSC transplants. Here, we cultured human CD34+ UCB cells and lineage depleted (Lin–) Balb/c BM cells up to 7 days in serum-free HSC expansion medium with hematopoietic growth factors. SUL-109 containing cultures were stored at 4°C for 3-14 days. UCB cells were tested for viability, cell cycle and reactive oxygen species (ROS). DMSO-cryopreserved Lin– BM cells or Lin– BM cells maintained for 14 days at 4°C were transplanted into RAG2−/− Balb/c mice and engraftment was followed for 6 months. Addition of SUL-109, which was easy and non-toxic, during hypothermic storage of expanded CD34+ UCB cells provided a significant improvement in cell survival of the immature CD34+/CD38- fraction after 7 days of hypothermic storage through scavenging of hypothermia-induced ROS and was able to preserve multilineage capacity of human CD34+ UCB cells up to 14 days of cold storage. In addition SUL-109 protected murine BM lineage negative cells from 14 days of hypothermic preservation and retained their engraftment potential after transplantation in immune-deficient RAG2−/− mice. In conclusion, SUL-109 is a promising novel chemical to be used as a protective agent during cold storage of human and murine HSCs to prevent hypothermia-induced apoptosis and to promote cell viability.