The effect of sodium ascorbate on the mechanical properties of hyaluronan-based vascular constructs

Esterified hyaluronic acid (HYAFF) is routinely used for clinical tissue engineering applications such as skin and cartilage. In a previous study we developed a technique for in vitro generation of cylindrical constructs from cellularized HYAFF flat sheets. In the present investigation we studied the possibility to improve mechanical properties of this vascular construct by the addition of sodium ascorbate (SA). Non-woven HYAFF flat sheets were seeded with porcine aortic smooth muscle cells (SMCs) and cultured for 14 or 28 days with standard medium or medium additioned with SA. In selected experiments HYAFF sheets seeded with SMCs were wrapped to obtain cylindrical shape and then cultured in control medium or SA additioned medium for up to 28 days. We estimated cell viability for flat sheets, and performed histological examination, analysis of extracellular matrix (ECM) deposition and mechanical tests on tubular constructs. The number of viable cells and ECM deposition increased with time in constructs cultured in the presence of SA, as compared to control group. Moreover, SA improved mechanical properties of the vascular construct lowering material stiffness and increasing tensile strength as compared to untreated controls. The addition of SA to the medium improved cell proliferation and ECM synthesis on this biodegradable material, which leads to the formation of well organized, mechanical resistant tissue-engineered structure.