Endothelial cell viability in the rat aortic wall.

Abstract

Aortic allografts may offer advantages over prosthetic materials for aortic valve replacement or reconstruction with a valved aortic conduit. Cellular viability may partly determine long-term allograft performance. To evaluate endothelial cell viability in a rat model, valved aortic conduits were subjected to collagenase digestion. The resulting endothelial cell suspension was labeled with Griffonia simplicifolia agglutinin-fluorescein isothiocyanate (GSA-FITC), a marker specific for vascular endothelial cells of the rat. The cells were then incubated with propidium iodide, which is excluded by viable cells. Flow cytometry evaluated endothelial cell viability by determination of percentage of GSA-FITC-positive cells that were negative for propidium iodide. Aortas were studied immediately after harvest or after storage at 4 degrees C in a nutrient medium for 3 to 21 days. Percentage of viable endothelial cells showed a progressive decline with increasing duration of storage. These results demonstrate flow cytometric measurement of endothelial cell viability, a factor of possible importance in assessing allograft storage methods, and show that endothelial viability declines with prolonged storage at 4 degrees C in a nutrient medium.