A decellularized porcine pulmonary valved conduit embedded with gelatin

Abstract

To prepare a tissue‐engineered pulmonary valved conduit (PVC) with good tensile strength and biocompatibility. Sixty adult porcine PVCs were used to determine the optimal decellularization time. Five juvenile porcine decellularized PVCs and five juvenile porcine crosslinked PVCs were subsequently prepared according to the optimized decellularization and crosslinking methods. All PVCs were implanted into juvenile sheep for 8 months and then were harvested for staining. With a low concentration of detergent (0.25% Triton X‐100+0.25% sodium deoxycholate), the decellularization effect on porcine PVCs was complete by 24 hours, and there was minimal damage to the matrix. Gelatin embedding and 1‐ethyl‐3‐(3‐dimethylaminopropyl) carbodiimide (EDC) crosslinking improved the biomechanical properties of decellularized PVCs and reduced their immunogenicity. After implantation, the diameter and thickness of the PVCs in the decellularized and crosslinked groups increased significantly. In both groups, the conduits were unobstructed, with soft and smooth inner walls and without thrombosis, ulceration or neoplasia. The valves slightly degenerated with mild to moderate regurgitation. CD31‐positive endothelial cells were visible on the inner surface of the conduits and valves. Scattered smooth muscle actin‐positive cells were found in the middle layer of the conduit. The percentage of CD4‐ and CD68‐positive cells and the calcium content were highest in decellularized porcine PVCs and lowest in ovine PVCs. The percentage of the matrix that was laminin‐positive in decellularized and crosslinked porcine PVCs was lower than it was in ovine PVCs. Gelatin‐embedded and EDC‐crosslinked porcine PVCs can be “hosted” in sheep, with good biocompatibility, growth potential, and reduced calcification.

Immunogenicity of decellularized extracellular matrix scaffolds: a bottleneck in tissue engineering and regenerative medicine

“…1-ethyl-3-(3-dimethylaminopropyl) carbodiimide (EDC) is another chemical crosslinker that has recently gained interest in reducing the immunogenicity of dECM scaffolds [209]. Despite GA and genipin, EDC crosslinks proteins without being a part of the final scaffold but with less potency, making the cytocompatibility of crosslinked products negligible.…”

Crosslinking strategies of decellularized extracellular matrix in tissue regeneration

“…124 The exposed collagen fibers and damaged physicochemical properties of decellularized vessels due to endothelial cell removal may lead to severe immune responses, material degradation, and post-transplantation thrombus, though with partially preserved microstructures and mechanical properties of native vessels. 125 Therefore, crosslinking reagents, besides the most commonly used GA with the potential risk of cytotoxicity and calcification, are expected to restore weakened strength and further improve vascular scaffolds for cardiovascular diseases. The ideal decellularized blood vessels are expected to (1) have matching biomechanical properties to handle physiological blood flow, (2) be biocompatible without host rejection and thrombogenesis, and (3) integrate with anastomosing vessels in vivo to promote angiogenesis.…”

“…The exposed collagen fibers and damaged physicochemical properties of decellularized vessels due to endothelial cell removal may lead to severe immune responses, material degradation, and post‐transplantation thrombus, though with partially preserved microstructures and mechanical properties of native vessels 125 . Therefore, crosslinking reagents, besides the most commonly used GA with the potential risk of cytotoxicity and calcification, are expected to restore weakened strength and further improve vascular scaffolds for cardiovascular diseases.…”

“…The resulting crosslinked scaffolds with moderate fibroblast filtration in vivo showed advantages for cell growth and matrix synthesis. Furthermore, gelatin‐embedded and EDC/NHS‐crosslinked decellularized porcine pulmonary valved conduits (PVCs), which showed improved physical properties with favorable re‐endothelialization, growth ability, and reduced calcification in sheep models, are proven promising for the reconstruction of the right ventricular outflow tract in congenital heart defects 125 . The tensile strength and thermal shrinkage temperature of the decellularized pulmonary artery walls were significantly increased after crosslinking, and the smoother surface and reduced fiber exposure contributed to reduced immunogenicity in vivo .…”

Application of Homograft Valved Conduit in Cardiac Surgery

“…Because cryopreserved homograft valved conduits carry donor cells that express relevant antigens, these cells can cause adverse host immune responses and lead to calcification, which in turn may require reoperation in young patients who receive a homograft valved conduit. Therefore, removal of the cellular component of the homograft valved conduit prior to implantation may reduce the immune response and calcification ( 116 ). In addition, removal of donor cells may encourage the proliferation of the cells with the ability to repair and remodel in receptor, thereby overcoming the limitations of degeneration of the homograft valved conduit over time and creating a valve with growth potential in younger patients, thus eliminating the need for reoperation.…”