VasCraft: new decellularized and re-endothelialized human vascular graft produced by tissue engineering for use in arterial bypass

Abstract Introduction Coronary artery bypass grafting (CABG) is a widely used surgical intervention for severe coronary artery disease, aiming to restore myocardial perfusion by bypassing occluded coronary arteries. The saphenous vein and internal mammary artery are the most used autologous grafts. However, their use is often limited by harvesting-related complications, long-term patency issues, and the scarcity of suitable vessels. To address these challenges, tissue-engineered vascular grafts have been explored as potential small-diameter (6 mm) alternatives for CABG, though a clinically viable solution remains elusive. Purpose To develop VasCraft, a bioengineered human vascular graft composed of a decellularized human saphenous vein re-endothelialized with umbilical cord blood-derived endothelial cells (CB-EC), as a potential arterial conduit. Methods Following Good Manufacturing Practice, human saphenous veins (VSh) from cadaveric donors underwent various decellularization protocols using ionic agents and/or detergents. The decellularized veins (DVSh) were analyzed for extracellular matrix (ECM) integrity, cellular residues and cytotoxicity to ensure biocompatibility. A 3D bioreactor was designed for DVSh luminal CB-EC seeding. A preclinical study was conducted in a porcine model to assess the biological response to the non-re-endothelialized DVSh. One pig received a DVSh graft in the right femoral artery, while the native artery in the left limb served as a control. Graft patency and permeability were monitored through ultrasound (baseline, 7, 15, and 30 days) and an angiography at study endpoint. Histological analysis was performed to evaluate inflammation and graft structural integrity. Results Among eleven decellularization protocols (Figure A.i), all achieved DNA concentrations below 50 ng/mg dry tissue (Figure A.ii). Most protocols preserved collagen and elastin, while detergent-based methods led to significant ECM degradation (Figure A.iii). Protocol 1 (detergent-free) was the optimal, preserving ECM components and eliminating cytoskeletal remnants. Cytotoxicity assays confirmed its biocompatibility. The developed flow-based 3D bioreactor successfully demonstrated CB-EC uniform endothelialization of the DVSh (Figure B). In the preclinical study, the non-re-endothelialized DVSh graft remained permeable at day 7, with no acute rejection. An aneurysm was detected at day 15, and by day 30, angiography revealed 95% stenosis. The native femoral artery maintained full patency (Figure C). Conclusion This study successfully optimized a decellularization protocol for VSh, developed a 3D bioreactor for endothelialization, and conducted a preclinical evaluation demonstrating graft biocompatibility and feasibility of the implantation technique. These findings support further large-scale preclinical studies in immunosuppressed pigs to assess VasCraft’s performance under clinically relevant arterial conditions.