The influence of copper (Cu) deficiency in a cardiomyocyte cell model (HL‐1 cell) of ischemia/reperfusion injury

Mitochondria are important mediators of cell death and this study examines whether mitochondrial dysfunction caused by Cu deprivation promotes cell death in a cell culture model for ischemia/reperfusion injury in cardiomyocytes. HL‐1 cells (donated by Dr. William C. Claycomb, LSU Health Sciences Center) were cultured for 3 days in the absence or presence of 80 μM TET, a Cu chelator. TET‐treated cells in comparison to untreated cells had lower cytochrome c oxidase activity (32.5±0.4 vs 65.0±4.3 nmol cyt c oxidized·min −1 ·mg −1 ) and lower Cu content (0.95±0.06 vs 2.07±0.08 ng Cu/10 6 cells). After 3 days of TET treatment, ischemia/reperfusion was simulated by replacing medium with nutrient‐free buffer and incubating in a hypoxic atmosphere for two hours followed by incubation in complete medium in a normoxic atmosphere for 90 min. Ischemic cells compared to control cells had reduced mitochondrial membrane potential (ΔΨ m ) (53±1 vs 42±1% depolarized cells) and increased apoptosis (16±1 vs 11±1% apoptotic cells) but TET treatment had no effect. However, following reperfusion, TET‐ treated compared to untreated cells exhibited lower ΔΨ m (55±1 vs 46±1% depolarized cells) and increased apoptosis (9.0±0.2 vs 6.9±0.2% apoptotic cells). These findings indicate that Cu status of cardiomyocytes is a determinant of reperfusion injury through a mechanism that likely involves mitochondrial dysfunction. Support ‐ USDA/ARS