Development of salmon collagen vascular graft: Mechanical and biological properties and preliminary implantation study

Elastic salmon collagen (SC) vascular grafts were prepared by incubating a mixture of acidic SC solution and a fibrillogenesis-inducing buffer containing a crosslinking agent [water-soluble carbodiimide (WSC)] in a tubular mold at 4°C for 24 h and then at 60°C for 5 min. Subsequently, re-crosslinking in ethanol solution containing WSC was performed. The dimension of the SC grafts was easily controlled by changing the size of the mold used. The compliance (stiffness parameter: β) and burst strength of the SC grafts (internal diameter, 2 mm; length, 20 mm; and wall thickness, 0.75 mm) that were prepared for implantation were 18.2 and 1434 mmHg, respectively; both these values were comparable with those of native vessels. Upon placement in rat subcutaneous pouches, the SC grafts were gradually biodegraded with little inflammatory reaction. The SC grafts were preliminarily implanted in rat abdominal aortas by using specially designed vascular connecting system. This system was used because the graft exhibited easy tearing and thus inadequate suturability. There was neither aneurysm formation nor graft rupture, but mild thrombus formation was seen within the 4-week observation period. These grafts may be ideal for use in regenerative medicine because we believe that SC would be completely replaced with native vascular tissues after implantation, although further improvement in the mechanical properties of the graft is needed for anastomosis.