Warm-ischemia and cold storage induced modulation of ferroptosis observed in human hearts donated after circulatory death and brain death.

Abstract

We investigated ferroptosis, a type of programmed cell death mechanism, in human hearts donated after brain death (DBD) and those donated after circulatory death (DCD), focusing on warm ischemia time (WIT) and cold storage. A total of 24 hearts were procured, with six from the DBD group and 18 from the DCD group. The DCD group was divided into three subgroups, each containing six hearts, based on different WITs of 20, 40, and 60 min. All procured hearts were placed in cold storage for up to 6 h. Left ventricular biopsies were performed at 0, 2, 4, and 6 h. We measured ferroptosis regulators [glutathione peroxidase 4 (GPX4), acyl-CoA synthetase long chain family member 4 (ACSL4), and transferrin receptor], iron content (Fe²⁺ and Fe³⁺), and lipid peroxidation (malondialdehyde, MDA) in the cardiac tissue. Modulation of ferroptosis was observed in both DBD and DCD hearts. Warm ischemia injury increased myocardial vulnerability to ferroptotic cell death. For DBD hearts, up to 6 h of cold storage increases cardiac levels of MDA, iron content, and ACSL4, thereby increasing vulnerability to ferroptotic cell death. In contrast, for DCD hearts with a WIT of 40 min or more, warm ischemia injury was identified as the primary factor contributing to increased myocardial susceptibility to ferroptotic cell death. Ferroptosis may serve as a promising target to optimize cold preservation for DBD hearts. For DCD hearts, strategies to inhibit ferroptosis should focus on the early warm ischemia phase to assess donor heart quality and suitability for transplantation.NEW & NOTEWORTHY The first human heart research explored the effects of ischemia on the myocardial ferroptotic cell death mechanism. Prolonged cold storage increases the susceptibility of DBD hearts to ferroptotic cell death. In contrast, warm ischemic injury appears to be the main factor leading to the vulnerability of DCD heart ferroptosis. Targeting ferroptosis could be beneficial in optimizing cold preservation for DBD hearts. However, for DCD hearts, interventions should focus on the early phase of warm ischemia.