The role of shear stress on mechanically stimulated engineered vascular substitutes: Influence on mechanical and biological properties

Vascular tissue engineering represents a promising field in the replacement of diseased vessels. The biological properties of three-dimensional (3D) collagen scaffolds indicate this material as a valid choice for vascular tissue engineering. Unfortunately, mechanical properties still remain unsatisfactory, due to a low burst pressure resistance and a plastic deformation. The use of a bioreactor to apply appropriate mechanical stresses have already shown a remodelling effect on the extracellular matrix and the behaviour of cells. In this study, we have shown the effect of the mechanical stress on elastin synthesis, which has a direct effect on the mechanical properties of the tissue-engineered vessel. We measured and compared the stress-strain curves, the elastic modulus and tenacity of a collagen tubular scaffold in the presence of C2C12 murine myoblasts cells, before and after the maturation in the bioreactor, applying a shear stress of 5 dynes/cm² for 3 days. Interesting evidence concerning the extracellular matrix structure, which significantly modify the biomechanical characteristics of the cellular scaffold, were observed, underlying the importance of focusing more effort in the research field of physiologically-guided 3D tissue-engineered substitutes.