The quest
The culturing of living cardiovascular substitutes, such as small-diameter vessels and heart valves, is a high effort activity. There is evidence that cells, which circulate in the blood flow, could be captured in a scaffold valve, such that a new valve is tissue-engineered on site. These cells would need to inhabit the scaffold and grow into a layered 3D tissue architecture and fulfill the functionality of a new heart valve. To study the cellular mechanisms, a model system is required that mimics the integrated in-vivo physiological environment. Within the NIRM consortium, substantial expertise on cell and tissue culturing was available, and LifeTec Group was invited to realize this physiological environment in which the required studies could be conducted.
What was done
LifeTec Group created a dynamic bioreactor system in which the scaffold-based valves could be cultured under physiologically relevant hemodynamic and structural loading conditions.
In existing bioreactor systems, cell-seeded valves are cultured in an open or closed configuration subjected either to physiological pressure (closed valve) or shear rate (open valve). The challenge in this project was to integrate these two loading conditions, inducing a realistic motion of the valves’ leaflets and a realistic impact loading at valve closure – while operating inside an incubator and allowing monitoring the valve during its growth. LifeTec Group’s research was successful, and the resulting bioreactor was validated to be capable of providing the right environment for and loading of the valves, while cells that are suspended in the circulation fluid could stay viable for a similar duration as in other culture environments.
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