Subscribe to RSS
DOI: 10.1055/s-0032-1332296
Mechanical integrity of Tissue Engineered Heart Valves under different flow conditions
Introduction: Valve replacement represents a common therapy for end staged valvular diseases. Currently used prostheses are limited by availability, durability or by the increased postoperative hemorrhagic risk. Tissue engineered heart valves (TEHV) are a promising approach to overcome the limitations of conventional heart valve prostheses. The aim of this study was to compare the mechanical integrity of TEHV after high-flow perfusion with and without pre-conditioning.
Methods: Non-degradable polyurethane heart valves (PUHV) were dynamically seeded with human saphenous vein fibroblasts (FB) and endothelial cells (EC) by using a special 3D-rotating bioreactor. Colonized PUHV were exposed to variable flow conditions (Group A: t1= 24h at 1 l/min, t2= 24h at 1.5 l/min, t3= 24h at 2 l/min/Group B: t1= 5 d at 1 l/min, t2= 24h at 1 l/min, t3= 24h at 1.5 l/min, t4= 24h at 2 l/min) using two different bioreactor systems (High flow bioreactor: HFBR and Conditioning bioreactor: CB). Samples were analyzed by immunohistochemistry (IHC), scanning electron microscopy (SEM), and real time polymerase chain reaction (RT-PCR).
Results: IHC staining revealed the mechanical integrity of EC and FB layers in both groups. SEM analysis demonstrated a stable cellular coating under both conditions. As shown by RT-PCR, Group B results in an increase of IL-6 and MCP-1 expression.
Conclusion: We have demonstrated that high-flow perfusion does not affect the integrity of the cellular coating of seeded PUHV. New HFBR offers a method to improve the reaction of cells to shear stress in vitro and finally to enhance the mechanical properties of tissue engineered cardiovascular prostheses.