Natural collagen scaffolds for tissue engineered blood vessels

Abstract

Small caliber synthetic grafts used for CABG are compromised by thrombogenicity and accelerated intimal thickening, resulting in early graft occlusion. Synthetic grafts do not possess the mechanical and biological properties of native artery. Tissue engineered blood vessels (TEBV) represents a new approach to alleviate problems associated with synthetic grafts. Endothelialization of small-caliber TEBV is essential in maintaining lumen patency. The purpose of this study was to characterize the structure; both mechanically and morphologically, of an endothelialized small-caliber TEBV. Porcine carotid arteries were decellularized and the mechanical properties were measured to ensure the conduit behaved similar to the native tissue. The TEBV were seeded with endothelial cells (EC) in a bioreactor where they were subjected to physiological conditions for 1 week. The results of the mechanical properties illustrated that the TEBV performs similar to the native artery with regards to stress, strain, and burst pressure. Hematoxylin and Eosin staining and Scanning Electron Microscope illustrated that Bovine EC, seeded on the luminal side, adhered to the matrix and formed a uniform monolayer. These results reveal that preconditioning of the cells in a bioreactor is important when forming a monolayer of EC. TEBV coated with EC posses many morphologic and functional characteristics and may potentially be useful clinically as vascular grafts.