Hypothermic storage of coronary endothelial cells reduces nitric oxide synthase activity and expression

Preservation with University of Wisconsin (UW) solution has been implicated in coronary artery endothelial damage and loss of endothelium-dependent va sodilatation. Therefore. the objective of this study was to investigate the effect of this solution on basal nitric oxide (NO) release from porcine co ronary endothelial cells (CEC). Cultures were exposed to cold (4 degreesC) storage in UW solution for 6. 8 and 12 h. Parallel cultures were incubated with control medium at 37 degreesC. After treatment. NO release was evaluat ed by nitrite production, a stable metabolite of NO. Activity of the consti tutive endothelial nitric oxide synthase (eNOS) was measured by the convers ion [H-3]-L-arginine to [H-3]-L-citrulline and eNOS protein expression by W estern blotting. Nitrite production by control cells was augmented with inc reasing times of incubation, whereas no change was observed in those cultur es preserved with UW solution. Activity of eNOS was significantly decreased compared to the respective control group by cold storage of cells for long er periods than 6 h. Such decrease was correlated with a diminished eNOS pr otein expression in CEC preserved with UW solution after 8- and 12-h storag e. These results suggest that prolonged hypothermic storage of CEC with UW solution does not preserve basal NO release because of a certain loss of eN OS protein, which may contribute to the reported injury of heart transplant s after long-term preservation. (C) 2000 Academic Press.