Making of Functional Tissue Engineered Heart Valve

摘要

The concept of tissue engineered heart valves offers an alternative to current heart valve replacements which is capable of addressing shortcomings such as lifelong administration of anticoagulants, durability and inability to grow. The ideal concept of a tissue engineered heart valve includes formation 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, regardless 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 calcification 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 scaffold with 300 fim 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 components of aortic heart valve leaflets including elastin. They exhibited myofibroblast-like morphology and have good cellular kinetics suitable for tissue engineering of cardiovascular tissues including aortic heart valves.