Key Points
- To compare the in vivo biological responses of an autologous cell-seeded biodegradable scaffold and an acellular scaffold implanted as pulmonary valve leaflets in sheep.
- Ovine artery myofibroblasts and endothelial cells were isolated, cultured, and seeded sequentially onto biodegradable polyglycolic and polylactic acid scaffolds using a collagen-containing medium.
- Scaffolds were implanted into sheep as dual pulmonary valve leaflet replacements (n=3) or as single leaflet replacements (cell-seeded construct n=2; plain acellular scaffold n=2) with follow-up at 6 and 9 weeks.
- Retrieved explants were evaluated via gross visual inspection and light microscopy.
- All animals undergoing double leaflet replacement survived only short-term (12, 24, and 36 hours), dying of heart failure secondary to severe pulmonary insufficiency.
- Short-term explants demonstrated that cell-seeded tissue-engineered constructs accumulated less fibrin and protein exudate than plain acellular scaffolds.
- At 6 and 9 weeks post-implantation, single-leaflet explants from both cell-seeded constructs and plain scaffolds showed well-organized granulation tissue.
Structured PICO
Does a tissue-engineered autologous cell-seeded scaffold improve biological responses compared to an acellular scaffold in an ovine pulmonary valve replacement model?
PPopulationOvine model (n=7 total: 3 for double pulmonary valve leaflet replacement, 4 for single valve leaflet replacement)
IInterventionTissue-engineered construct (synthetic biodegradable scaffold of polyglycolic acid and polylactic acid seeded with autologous myofibroblasts and coated with endothelial cells)
CComparatorPlain acellular scaffold (synthetic biodegradable scaffold of polyglycolic acid and polylactic acid)
OOutcomeBiological response (visual and light microscopy analysis of retrieved valve leaflet tissues)surrogate
Tissue-engineered heart valve leaflets demonstrate better early antithrombogenic responses than plain scaffolds in an ovine model, though long-term reparative responses appear similar.