Développement de techniques de construction de valves aortiques par génie tissulaire
|Advisor:||Ruel, Jean; Auger, François A.|
|Abstract:||Heart valves diseases lead annually to nearly 300 000 replacement surgeries, mostly performed on aortic valves. Mechanical or tissue valves are largely used to replace dysfunctional heart valves but they present serious drawbacks, mainly for young patients, since these non-living substitutes are unable to remodel according to physiological environment changes. Tissue engineering aims at the development of new biological organ substitutes created with living cells. Tissue engineered heart valves may be able to fully integrate their physiological environment and hence eliminate the problems encountered with mechanical and tissue valves. Porous polymer scaffolds or decellularized heart valves are current tissue engineering techniques that are being studied in order to develop new biological substitutes. This thesis, however, presents the development of an entirely new construction technique based on the self-assembly method that can recreate the aortic valve structure by using only human dermal fibroblasts cell sheets. The many steps achieved toward the development of this new construction technique are detailed in this thesis. The plane thick tissue fabrication method is first explained, along with the incremental evolutive process that led to the construction of four heart valve prototypes. The construction technique uses several templates to assist the three-dimensional shaping of the substitutes, which resemble the natural shape of the native aortic valve. Dynamic stimulations were also performed in a custom-made bioreactor and the valve exhibited a normal behavior under various flow and pressure waveforms. No damage was noted on the plane thick tissue after the mechanical stimulation. Besides, a feasibility study on the decellularization of porcine heart valves was conducted using Trypsin/EDTA in order to assess the potential of such a construction technique. Finally, the mechanical characterization of the plane tissue used for the construction of the valves is also presented. The results of this study confirm the ability of the tissues to act as a heart valve substitute. The new material is also compared to other commonly used materials in heart valve replacement or repair.|
|Document Type:||Thèse de doctorat|
|Open Access Date:||23 April 2018|
|Collection:||Thèses et mémoires|
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