Morphological and functional techniques for assessing endothelial integrity: the use of Evans blue dye, silver...

The endothelium is an important aspect of vascular function and pathology. Simple and reliable methods for assessing the presence or absence of endothelium in vascular specimens are presented. Intravenous Evans blue dye that stains endothelial denuded vessel walls in recommended for the macroscopic visualization of endothelial injury in gross intact arterial specimens. Scanning electron microscopy (SEM) is often used for investigating microscopic endothelial injury, but the differentiation of endothelial cells from underlying vessel wall structures can be difficult. By demarcating endothelial cell borders, silver stains allow for better endothelial identification by SEM. A third technique describes assessing endothelial integrity by how well it functions and involves the selective production of endothelium derived relaxing factor. As cardiovascular surgeons become more involved in basic vascular research, a review of these techniques should be appropriate and helpful.