Tissue engineering of heart valves – human endothelial cell seeding of detergent acellularized porcine valves1

TLDR

Tissue engineering of heart valves seeks to overcome the limited durability and lack of growth potential of glutaraldehyde‑fixed and mechanical valves, which are problematic especially for children. The study aimed to develop a methodology combining detergent‑acellularized porcine aortic valves with human endothelial cells to create a tissue‑engineered valve. Porcine valves were acellularized with Triton detergent, endothelial cells were isolated from human saphenous veins, expanded in vitro, and seeded onto the matrix, with acellularity verified by light and electron microscopy. The acellularization removed nearly all native cells while preserving the 3D fiber architecture, and the reseeded valves supported confluent human endothelial cultures for up to three days, suggesting potential for autologous valve engineering.

Abstract

Tissue engineering of heart valves represents a new experimental concept to improve current modes of therapy in valvular heart disease. Drawbacks of glutaraldehyde fixed tissue valves or mechanical valves include the short durability or the need for life-long anticoagulation, respectively. Both have in common the inability to grow, which makes valvular heart disease especially problematic in children. The aim of this study was to develop a new methodology for a tissue engineered heart valve combining human cells and a xenogenic acellularized matrix.Porcine aortic valves were acellularized by deterging cell extraction using Triton without tanning. Endothelial cells were isolated in parallel from human saphenous veins and expanded in vitro. Specimens of the surface of the acellular matrix were seeded with endothelial cells. Analysis of acellularity was performed by light microscopy and scanning electron microscopy. Cell viability following seeding was assayed by fluorescence staining of viable cells.The acellularization procedure resulted in an almost complete removal of the original cells while the 3D matrix was loosened at interfibrillar zones. However the 3D arrangement of the matrix fibers was grossly maintained. The porcine matrix could be seeded with in vitro expanded human endothelial cells and was maintained in culture for up to 3 days to document the formation of confluent cultures.Porcine aortic valves can be almost completely acellularized by a non-tanning detergent extraction procedure. The xenogenic matrix was reseeded with human endothelial cells. This approach may eventually lead to the engineering of tissue heart valves repopulated with the patients own autologous cells.