No abstract

In autologous heart valve tissue engineering, there is an ongoing search for alternatives of fetal bovine serum (FBS). Human platelet-lysate (PL) might be a promising substitute. In the present article, we aimed to examine the tissue formation, functionality, and mechanical properties of engineered three-dimensional tissue constructs cultured in PL as a substitute for FBS. Our results show that tissue constructs that were cultured in PL and FBS produce similar amounts of collagen, glycosoaminoglycans, and collagen crosslinks, and that the cellular phenotype remains unchanged. Nevertheless, mechanical testing showed that the ultimate tensile strength in PL constructs was on average approximately three times lower as compared to FBS (0.25 vs. 0.74 MPa, respectively, p<0.01), and also the elastic modulus was almost three times lower (1.33 MPa of PL constructs vs. 3.94 MPa of FBS constructs, p<0.01). Additional tests indicated that this difference might be explained by different collagen fiber architecture possibly due to increased production of matrix-degrading proteases by cells cultured in PL. In summary, our results indicate that PL is not preferred for the culture of strong heart valve tissue constructs.

Fibrous tissues have the ability to adapt to their mechanical environment. Adaptation can be guided by the direction and magnitude of the imposed load, leading to structural changes and altered mechanical properties. This is important for proper functioning of all fibrous tissues, especially those with a load bearing capacity such as tendons, ligaments, and tissue-supporting fibrous sheets. The mechanism by which fibrous tissues adapt to alterations in their mechanical environment remains unresolved, and such knowledge will be helpful to guide repair and engineering of artificial fibrous tissues.