In vivo Evaluation of Polyester Arterial Grafts Coated with Albumin: The Role and Importance of Cross-Linking Agents

Abstract

Previous in vitro studies have predicted that the type of chemical used to crosslink albumin-coated polyester arterial prostheses may influence the rate of bioerosion of the albumin layer in vivo. This study has confirmed that the healing process of this type of compound prosthesis does indeed depend on the nature and concentration of the cross-linking agent used. Four series of implantations in the thoracic aorta of dogs for scheduled periods for 4 h up to 6 months were conducted using 1.6% glutaraldehyde, 2.5% glutaraldehyde and 0.2 M carbodiimide as the alternative cross-linking agents plus a nonalbuminated preclotted polyester prosthesis which served as the control. The pathology of the explanted grafts revealed that in the short and medium term the rate of healing and the extent of tissue ingrowth was dependent initially on the presence of and later on the rate of bioerosion of the albumin layer. After 3 months in situ, the prostheses coated with albumin cross-linked with 1.6% glutaraldehyde and carbodiimide had healed more rapidly and were invaded by more extensive tissue ingrowth than the one cross-linked with 2.5% glutaraldehyde or the preclotted control. Moreover, the migration of cells over the carbodiimide-treated surface was the most fully developed and most regularly organized of all four series. Immunostaining revealed that the presence of glutaraldehyde induced an inflammatory response which failed to support the growth of normal luminal cells with the endothelial phenotype.

The cellular response to transglutaminase-cross-linked collagen

“…To overcome these problems, collagen has been cross-linked by a variety of agents-a subject of much recent research to find methods of preventing rapid absorption by the body [4]. However, these methods suffer from the problem that the residual catalysts, initiators and unreacted or partially reacted cross-linking agents used can be toxic or cause inflammatory responses if not fully removed or, simply, not cost-effective or practical at the large scale [5][6][7]. As a consequence, research continues to find alternative methods to stabilise collagen which are natural, milder, efficient and more practical.…”

Biomaterial Enhanced Regeneration Design Research for Skin and Load Bearing Applications

“…Polymerized microaggregates of albumin can serve as agents for radiocontrast and ultrasonic imaging of the circulatory system [11]. Albumin is also used to coat prosthetic blood vessel grafts and vascular catheters to passivate these surfaces so as to minimize platelet aggregation and thrombotic consequences [11,110,111,112,113,114].…”

Endothelialization of Crosslinked Albumin-heparin Gels

“…For the impregnation of vascular grafts, mixtures of heparin(oids) and collagen, albumin, or proteins with an RGD sequence, have been the subject of many investigations (20). Guidoin et al (21,22) for instance, who compared different sealants for vascular prostheses, observed that the healing process of albuminated grafts was comparable to preclotted controls. However, contrary to collagen-impregnated grafts, tissue ingrowth of albuminated Dacron prostheses in pigs was limited (23).…”