Abstract 20221: In vivo Implantation of a Functional Tissue Engineered Stentless Pulmonary Valve Using Bone-Marrow-Derived Mesenchymal Stem Cells and Circulating Endothelial Progenitor Cells
Purpose: The feasibility of stentless pulmonary valve (PV) in congenital cardiac surgery is under study. We investigated the functional potential of poly-4-hydroxybutyrate (P4HB) scaffolds by determining the most suitable thickness and ratio of co-cultured progenitor cells for construction of pulmonary leaflets and annular sewing ring in tissue engineered (TE) stentless PV.
Methods: Melt-blown fibronectin (FN)-coated P4HB scaffolds (with varying thickness 100-,220-,440-,660 μM were seeded with different percentages (220.127.116.11) of characterized ovine bone marrow-derived mesenchymal stem cells (MSC)and peripheral blood-derived endothelial progenitor cells (EPC) for 3 days followed by 18 days in a laminar fluid flow system.
Results: H&E and electron microscopy of FN-coated scaffolds (100 μM and 220 μM) seeded both with 40% MSC and 60% EPC demonstrated enhanced cellularity, extracellular matrix formation, and cellular ingrowth into the interstitial layer of P4HB scaffolds. Both pre-coated and uncoated scaffolds independent of thickness and cell percentage demonstrated primary surface expression of CD31+, vWF+ and VEGF-R2 + cells; α-SMA+ cells were found both on the surface and in the interstitium evidenced by IHC. Immunoblotting revealed increased expression of α-SMA+ in 100 μM and 220 μM scaffold thickness seeded with 40% MSC and 60% EPC. Mechanical testing demonstrated increased tensile strength over strain in 100 μM and 220 μM seeded with 40% MSC and 60% EPC compared with other test groups and uncoated controls (25–60%). Autologous TE stentless PV using 220 μM for PV leaflet covered with 100 μM for annular sewing ring was successfully placed in PV position. The neo-tissue integrity allowed secure anastomosis with adequate tensile strength. Echocardiography demonstrated normal biventricular function, absence of anastomotic dilatation and good leaflet coaptation with trivial central regurgitation.
Conclusions: This demonstrates the successful creation of an anatomically functional, autologous TE stentless PV using sequentially seeded progenitor cell sources. This suggest the importance of scaffold thickness and ratio of seeded cells in the suturability of TE stentless PV.
- © 2010 by American Heart Association, Inc.