PR002865 (Project)

Description:Introduction: Donation after circulatory death (DCD) criteria serves as a potential strategy to expand the organ pool for heart transplantation. However, DCD procurement introduces prolonged warm ischemic times that accelerate endothelial and cardiomyocyte injury. Hypothermic oxygenated perfusion (HOPE) has emerged as a novel metabolic preservation strategy, yet its biological mechanisms remain undefined. We investigated how HOPE preservation modulates cardiomyocyte viability and myocardial metabolic stability after DCD in a porcine model. Methods and Results: Following induced circulatory arrest and reperfusion with or without in situ normothermic regional perfusion (NRP), porcine hearts were preserved for 2 hours by static cold storage (SCS) or up to 24 hours by HOPE and reanimated using a ex vivo Langendorff circuit, under normothermic conditions. HOPE preservation maintained myocardial structure, cardiomyocyte viability, and sinus rhythm after 24 hours, sixfold beyond the conventional preservation window. Flow cytometry revealed measurable populations of troponin-positive viable cardiomyocytes after 24-hour HOPE, in contrast to complete loss after 24-hour SCS. RNA sequencing and metabolomics demonstrated minimal transcriptional or metabolic shift between 2-hour SCS and 24-hour HOPE hearts, with preservation of oxidative and glycolytic balance and limited inflammatory activation. In contrast, omission of NRP during procurement resulted in marked loss of contractility and cardiomyocyte integrity, underscoring its potential role in pre-preservation harvest in a porcine model. Conclusions: In a swine model extended hypothermic oxygenated perfusion preservation sustains myocardial and metabolic integrity after circulatory death by minimizing transcriptional and metabolic injury signatures. These findings identify a biologically distinct preservation state that mitigates ischemia-reperfusion injury and may inform novel strategies for organ and tissue preservation.