TISSUE ENGINEERING

Abstract

PURPOSE STUDY In cardiovascular tissue engineering the use of a 3-D scaffold might be beneficial to create new structures like valves or vessels. The most common degradable scaffolds in tissue engineering are PGA (Poly Glycolic Acid) polymers. A disadvantage of PGA is the production of lactat acid during degradation resulting in a local acidosis. The comparison of a porous (100–300μm) polyesterurethane (PU) vs non-woven PGA was undertaken in this study. METHODS PGA and PU (n=9) 2,8 sqcm sheets were seeded in four 24 hour intervals with human myofibroblasts (4.0±106 cells/sheet). Dulbecco's Medium supplemented with 1 mM L-ascorbic acid 2-phosphate was used. After 2 weeks, a MTT assay was performed to evaluate the number of attached cells. Tissue development was evaluated by light, transmission and scanning electron microscopy. Hydroxyproline assay was performed as a marker of collagen production after 6 weeks. SUMMARIZE RESULTS The cell attachment after 2 weeks was significantly (p < 0.01) higher in the PGA group (4.5±0.67 104cells) than in the PU group (1.9±0.41 104cells). The collagen production after 6 weeks was significantly (p < 0.01) higher in the PGA group (8.52±2.37 μg) vs the PU group (3.81±0.20 μg). Light microscopy of all the cellular sheets showed myofibroblasts surrounded by extracellular matrix (ECM). The transmission electron microscopy revealed relatively more local necrosis in the PGA group, possibly as a result of a local lactate acidosis from the PGA degradation. The higher ECM formation on the PGA scaffold might result from the initially superior cell attachtment in comparison to PU. Nevertheless by incorporation of biologically active molecules to PU structure, comparable cell attachment and tissue development might be realized