Short- and long term preservation of cardiac tissue-engineered constructs

Abstract

Abstract Funding Acknowledgements Type of funding sources: Public grant(s) – EU funding. Main funding source(s): This research was financially supported by the Gravitation Program ‘‘Materials Driven Regeneration,’’ funded by the Netherlands Organization for Scientific Research (024.003.013) and the EU-funded project BRAV∃ (H2020, ID:874827). Background Cardiac tissue engineering (cTE) has already advanced towards the first clinical trials, investigating safety and feasibility of cTE construct transplantation in failing hearts. However, the lack of well-established preservation methods poses a hindrance to further scalability, commercialization, and transportation, thereby reducing their clinical implementation. Purpose In this study, hypothermic (short-term) preservation (4°C), and slow and fast freezing methods for cryopreservation, at -196°C and -150°C respectively, were investigated as potential solutions to extend the cTE construct implantation window and increase their clinical applicability. Material and Methods The cTE model used consisted of induced-pluripotent stem cell-derived cardiomyocytes and human cardiac fibroblasts embedded in a natural-derived hydrogel and supported by a polymeric melt electrowritten hexagonal scaffold. Constructs, composed of cardiomyocytes of different maturity, were preserved for three days, using several commercially available preservation protocols and solutions. Their viability, function (BPM and calcium handling), and metabolic activity were investigated after rewarming. Results Our observations suggest that cardiomyocyte maturation did not influence post-rewarming viability, however, aging positively influenced construct function pre- and post-storage. Hypothermic preservation in Hypothermosol ensured retained construct viability and function. Furthermore, fast-freezing outperformed slow-freezing, but both viability and function were severely reduced after rewarming. Conclusion In conclusion, whereas long-term preservation remains a challenge, hypothermic preservation in Hypothermosol represents a promising solution for cTE construct short-term preservation and potential transportation, aiding in off-the-shelf availability, ultimately increasing their clinical applicability.Graphical abstract