Addition of a Water-Soluble α-Tocopherol Analogue to University of Wisconsin Solution Improves Endothelial Viability and Decreases Lung Reperfusion Injury

Background. Reperfusion injury following lung preservation has been associated with free radical formation and subsequent endothelial cell damage. Trolox is a water-soluble analogue of the free radical scavenger α-tocopherol. We hypothesized that addition of this form of vitamin E to University of Wisconsin (UW) solution would decrease reperfusion injury and improve lung function after cold ischemic preservation. Materials and methods. Bovine aortic endothelial cells were cultured and stored at 4°C for 12, 24, and 48 h in UW or UW + Trolox (UWT). Endothelial cell viability after storage was assessed by dimethylthiazole tetrazolium cytotoxicity assay. An isolated rat perfused lung (IPL) model was used and lungs were flushed with the respective solutions with cold storage times of 6 and 12 h. Following storage, the lungs were reperfused with fresh blood and lung function was assessed by blood gas analysis, alveolar–arterial gradient, and compliance. Results. There was no difference in endothelial cell viability between UW and UWT after 12 or 24 h; however, UWT had higher endothelial cell viability than UW with 48 h of cold ischemic storage. Using the IPL model, the pO2 was higher with UWT than UW after 6 and 12 h of cold ischemia. The alveolar–arterial oxygen difference was significantly lower for UWT versus UW at 6 h. UWT provided increased compliance at 6 and 12 h of ischemia. Conclusions. The addition of a water-soluble vitamin E analogue to UW solution resulted in increased endothelial cell viability after prolonged storage and improved whole lung preservation in the postreperfusion period as evidenced by higher oxygenation and increased compliance. These results are clinically relevant as the lung is extremely sensitive to reperfusion injury and UW solution is being increasingly used in lung transplantation and remains the predominant solution in abdominal organ transplantation.