Caracterització de l’adhesió cel·lular en stents coronaris

Abstract

Cardiovascular bioresorbable stents (CBS) were introduced to overcome the limitations of permanent stents. They offer the potential to improve long-term patency rates and provide support just long enough for the artery to heal itself. Ideally, CBS should meet three requirements: 1) CBS degradation should have the minimum toxicity to the body, 2) CBS degradation rate should match the recovery rate of vascular tissue, and 3) CBS should induce rapid endothelialisation. While the first and second requirements have been deeply studied the last requirement had been overlooked. This work taste different sterilization methods on the stents and studies the effects of stents geometry and material, such as Polycaprolactone (PCL) or Polylactide Acid (PLA), over the cell proliferation. Three sterilization methods have been applied such as ethanol 70%, ultraviolet lamp and antibiotic sterilization. All treatments have been performed for different times: 0.5h, 1h, 8h and 16h. Supplemented Dulbecco’s Modified Eagle’s Medium (DMEM) with phenol red (pH indicator) and without penicillin/streptomycin has been added after different treatments. Remaining infection is indicated by yellowing of the media and increased of media opacity. With regards to Ethanol treatment, all samples treated below 8 hours show signs of infection, while samples treated during 8 and 16 hours exhibit a complete sterilization. Therefore, subsequent chosen methodology for sterilization has been Ethanol 70% overnight and Ultraviolent Lamp 20 min. To elucidate cell behaviour on stent, sterilized parts has been placed in non-adherent microplates and seeded with a final concentration of 20000 Murine 3T3 Fibroblasts per stent. Cell proliferation has been tested by MTT assay. Results show a strong influence of flow rate, number of cells and material over 3T3 growth (p<0.05), while stent cell geometry did not show significant influence. Cell adhesion in the stents has been visualized by means of a confocal laser microscope