Conclusions
As pulse and flow conditions are modulated, complex mechanical changes are occurring that modify the elastic modulus differentially in both physiologic and failure ranges. Mechanical properties play an important role in graft patency, and a dynamic relationship between structure and function occurs during graft remodeling. These investigations have shown that as cells migrate into this ex vivo scaffold model, significant variation in material elasticity occurs that may have important implications in our understanding of early-stage vascular remodeling events.
Methods
A perfusion bioreactor system and acellular human umbilical veins were used as a model three-dimensional vascular scaffold on which human myofibroblasts were seeded and cultured under static or defined pulsatile conditions. Cell function in relation to graft mechanical properties was assessed.
Results
Cells doubled in density from approximately 1 × 10(6) to 2 ± 0.4 × 10(6) cells/cm ringlet, whereas static cultures remained unchanged. The material's compressive stiffness and ultimate tensile strength remained unchanged in both static and dynamic systems. However the Young's modulus values increased significantly in the physiologic range, whereas in the failure range, a significant reduction (66%) was shown under dynamic conditions. Conclusions: As pulse and flow conditions are modulated, complex mechanical changes are occurring that modify the elastic modulus differentially in both physiologic and failure ranges. Mechanical properties play an important role in graft patency, and a dynamic relationship between structure and function occurs during graft remodeling. These investigations have shown that as cells migrate into this ex vivo scaffold model, significant variation in material elasticity occurs that may have important implications in our understanding of early-stage vascular remodeling events.