The care of congenital heart valve disorders is inadequate at the present time. Both conventional mechanical heart valve prostheses and non-viable biological heart valve prostheses have serious limitations in paediatric heart surgery applications.
Therefore, the purpose of our research is the development of a viable, autologous heart valve prosthesis, with the potential for remodelling and the ability to regenerate and repair itself. In addition to being physiologically compatible, the ability of the valve to grow with the individual is an essential goal.
Figure 1 illustrates the principle of heart valve moulding technique developed in our group. cells (myofibroblasts and endothelial cells) are isolated from a biopsy and expanded in culture until a sufficient number of cells are acquired. In parallel to cell cultivation, the components for the fibrin gel matrix are isolated from an autologous blood sample and modified for the application.
A homogenous suspension of myofibroblasts and the fibrinogen component of the matrix is subsequently formed, and added to an individually customised mould using our injection moulding technique. Following the addition of starter solution, consisting of calcium and thrombin, the moulded gel polymerises within 2-3 minutes. This short polymerisation time allows an adequate, homogenous distribution of cells throughout the valve structure.
In the subsequent cultivation phase, tissue development is stimulated by cultivating the valve in a biomimetic bioreactor system. After an appropriate cultivation period, a further step involves the seeding of endothelial cells on the valve surface, which is also performed under suitable dynamic conditions in a bioreactor system. The result of the manufacturing process is a completely autologous heart valve (Figure 2), which can be (re)transplanted into the patient.