The Decellularized Vascular Allograft as an Experimental Platform for Developing a Biocompatible Small-Diameter Graft Conduit in a Rat Surgical Model

Abstract

PurposeThe present study was aimed to assess the feasibility of using decellularized aortic allograft in a rat small animal surgical model for conducting small diameter vascular tissue engineering research.Materials and MethodsDecellularized aortic allografts were infra-renally implanted in 12 Sprague-Dawley (SD) adult rats. The conduits were harvested at 2 (n = 6) and 8 weeks (n = 6), and assessed by hematoxylin and eosin (H&E), van Gieson, Masson Trichrome staining, and immunohistochemistry for von Willebrand factor, CD 31+, and actin.ResultsConsistent, predictable, and reproducible results were produced by means of a standardized surgical procedure. All animals survived without major complications. Inflammatory immune reaction was minimal, and there was no evidence of aneurysmal degeneration or rupture of the decellularized vascular implants. However, the aortic wall appeared thinner and the elastic fibers in the medial layer showed decreased undulation compared to the normal aorta. There was also minimal cellular repopulation of the vascular media. The remodeling appeared progressive from 2 to 8 weeks with increased intimal thickening and accumulation of both collagen and cells staining for actin. Although the endothelial like cells appeared largely confluent at 8 weeks, they were not as concentrated in appearance as in the normal aorta.ConclusionThe results showed the present rat animal model using decellularized vascular allograft implants to be a potentially durable and effective experimental platform for conducting further research on small diameter vascular tissue engineering.

In VivoRemodeling of Fibroblast-Derived Vascular Scaffolds Implanted for 6 Months in Rats

“…The lumen of the explants was infiltrated by SMC, most likely originating from the native media at the anastomotic sites. Furthermore, that neomedia were shown to be covered by a monolayer of ECs, which is in accordance with in vivo endothelialization and SMC infiltration of acellular grafts in rats reported previously [18, 28, 29]. …”

“…Some of the earliest instances, in 1985, reported implantation of synthetic scaffolds comprised of 95% polyurethane and 5% poly-L-lactic acid in Wistar rats for 6 [16] and 12 weeks [17]. More recently, another study has reported the implantation of completely decellularized aorta allografts implanted for two and eight weeks in Sprague-Dawley rats [18]. Other studies have specifically involved tissue-engineered vascular constructs that were decellularized prior to implantation in nude rat models [14, 19] and other models including mice [20], sheep [21], and pigs [22].…”

Animal models for vascular tissue-engineering

“…TEVs from different biomaterials such as a polysaccharide gel [44] or decellularized rat aortas [45] have been tested in rats with various degrees of success. A severe combined immunodeficiency (SCID) mouse model was developed by Lopez-Soler and colleagues for testing xenogeneic TEVs [46].…”

Vascular Grafting Strategies in Coronary Intervention

“…Following 8 weeks implantation, intimal thickening due to increased collagen fibers and SMαA-positive cells was observed. Although vWf staining revealed the presence of endothelial-like cells on the luminal surface of the implanted grafts, the expression was noticeably less than the native aorta (Hwang et al, 2011). In a related study, Akhyari and co-workers harvested rat aortae, which the authors decellularized and coated with fibronectin.…”