Macromolecular and histological studies of new tissue formation in velour vascular prostheses

The nature and characteristics of the tissue which develops on the inner surfaces of vascular arterial prostheses have been investigated by means of histological and biochemical criteria. Velour prosthetic tubes were implanted as aortic segmental replacements in the dog. On the 60th postoperative day, a neointimal layer of collagen covered with flattened endothelial-like cells was noted. However, despite this morphological evidence the microsomic and cytosolic enzymes implicated in the biosynthesis of glycosamino-glycuronoglycans were significantly modified in comparison with the normal aortic wall. The marked decrease in enzymes corresponding to the initiation of the glucidic linkages suggests that the biosynthesis of the macromolecular components responsible for the normal blood vaessel interfact was impaired in these newly developed tissues. Therefore, it is suggested that this newly developed tissue cannot be considered as a true vascular endothelium.