REDV‐modified decellularized microvascular grafts for arterial and venous reconstruction

Abstract Recently, a decellularized microvascular graft (inner diameter: 0.6 mm) modified with the integrin α4β1 ligand, REDV, was developed to provide an alternative to autologous‐vein grafting in reconstructive microsurgery, showing good early‐stage patency under arterial flow in rats. This consecutive study evaluated its potential utility not only as an arterial substitute, but also as a venous substitute, using a rat‐tail replantation model. Graft remodeling depending on hemodynamic status was also investigated. ACI rat tail arteries were decellularized via ultra‐high‐hydrostatic pressure treatment and modified with REDV to induce antithrombogenic interfaces and promote endothelialization after implantation. Grafts were implanted into the tail artery and vein to re‐establish blood circulation in amputated Lewis rat tails (n = 12). The primary endpoint was the survival of replants. Secondary endpoints were graft patency, remodeling, and regeneration for 6 months. In all but three cases with technical errors or postoperative self‐mutilation, tails survived without any evidence of ischemia or congestion. Six‐month Kaplan–Meier patency was 100% for tail‐artery implanted grafts and 62% for tail‐vein implanted grafts. At 6 months, the neo‐tunica media (thickness: 95.0 μm in tail‐artery implanted grafts, 9.3 μm in tail‐vein implanted grafts) was regenerated inside the neo‐intima. In conclusion, the microvascular grafts functioned well both as arterial and venous paths of replanted‐rat tails, with different remodeling under arterial and venous conditions.