Making of Functional Tissue Engineered Heart Valve

Abstract

The concept of tissue engineered heart valves of-fers an alternative to current heart valve replacements which is capable of addressing shortcomings such as lifelong adminis-tration of anticoagulants, durability and inability to grow. The ideal concept of a tissue engineered heart valve includes forma-tion of functional valve on the basis of a rapidly absorbable scaffold which provides temporary support until the cells produce their own matrix proteins. The structural integrity and biomechanical profile of the tissue engineered heart valves ultimately depend on this matrix formation. However, regard-less of numerous attempts, the complete extracellular matrix for aortic heart valves especially elastin which is critical for its proper functioning has not been successfully regenerated in vitro. Polyurethane (PU) has been investigated for decades as a scaffold for heart valves but progress was impeded by calcifi-cation and degradation of the material. Improved biocompati-bility and mechanical properties of PU have reignited interest in it as a potential valve replacement in recent years. Electros-pinning enables nanofibers to be produced which have larger surface areas thereby encouraging cell growth. Since the thickness of the fibres can be controlled, electrospun PU scaf-fold with 300 μm thickness required for heart valve leaflets was produced in our study. Human umbilical cord mesen-chymal stem cells (hMSCs) were seeded onto these scaffolds and were cultured in vitro by mechanical stimulation. This resulted in the production of all the extracellular matrix com-ponents of aortic heart valve leaflets including elastin. They exhibited myofibroblast-like morphology and have good cellu-lar kinetics suitable for tissue engineering of cardiovascular tissues including aortic heart valves.