Modified Approach to Construct a Vascularized Coral Bone in Rabbit Using an Arteriovenous Loop

Abstract

The most important factor for the survival of thick three-dimensional tissues is the degree of vascularization. In this study, a modified arteriovenous loop (AVL) model was developed to prefabricate an axial vascularized tissue-engineered coral bone. In group A (n = 28), an arteriovenous fistula between rabbit femoral artery and vein was anastomosed to form an AVL. The AVL was placed in a coral block (6 x 8 x 10 mm (3)) as a vascular carrier. The complex was wrapped with polytetrafluoroethylene membrane and implanted subcutaneously. In group B (n = 20), there was no vascular carrier, and the same dimensional coral was directly implanted beneath inguinal skin. After 2, 4, 6, and 8 weeks, the rabbits were perfused with heparinized saline (for scanning electron microscopy), India ink (for histological examination), and ethylene perchloride (for vascular casts) via the abdominal aorta. In group A, histology showed that newly formed vasculature extended over the surfaces and invaded the entire coral blocks. The vascular density was significantly superior to that in group B. Vascular casts showed that new blood vessels robustly sprouted from the AVL. Scanning electron microscopy demonstrated that there were minute sprouting cavities in the vascular endangium. In this model, an axial vascularized coral bone could be effectively constructed.

Vascularizing engineered tissues for in vivo and in vitro applications

“…In this technique, the engineered tissue is placed inside the host, and essentially employs the host as the 'bioreactor' to develop the vascular supply in the engineered tissue, with the potential to then move the engineered tissue to a more permanent location. The most common method of in vivo conditioning is to create an arteriovenous (AV) loop ( colour Plate XXIII ) in which a vascular graft is surgically inserted as a bypass (or loop) from a small artery to a nearby venule (Mian et al , 2000;Kneser et al , 2006;Lokmic et al , 2007;Manasseri et al , 2007;Morritt et al , 2007;Ren et al , 2008;Dong et al , 2010;Beier et al , 2011;Boos et al , 2013). Within the space created by the loop, a tissue engineered construct is placed, and small vessels can sprout from the AV loop and enter the engineered tissue to provide nutrients and remove waste products.…”