ANDRES KOTSAR A Biodegradable Urethral Stent with New Braided Configuration and Drug-eluting Properties

The first aim of this study was to evaluate the biocompatibility and degradation as well as potential clinical use of a new biodegradable PLGA (copolymer of L-lactide and glycolide acid) urethral stent with a braided mesh configuration. The second and at the same time, the main objective of this study was to develop a new drug-eluting biodegradable urethral stent. The biocompatibility profile of this new generation stent was tested and analysed in both in vitro and in vivo experimental studies. The degradation and biocompatibility profiles of the new braided stent were investigated in an experimental study in 24 male rabbits. Braided PLGA stents were compared with metallic stents in situ in the rabbit urethra. PLGA stents of the same configurations were evaluated also in a pilot clinical study in 10 patients combining a urethral stent and dutasteride in the treatment of acute urinary retention due to benign prostatic hyperplasia. The safety, biocompatibility and efficacy of new biodegradable PLGA urethral stent materials with drug-eluting properties were evaluated preclinically using standardized muscle implantation tests in 18 animals and in situ urethral biocompatibility testing was conducted in 16 rabbits – with indomethacin, dexamethasone and ciprofloxacine being the primary pharmacological agents examined. Additional studies were carried out with 24 rabbits concentrating on indomethacin-eluting stents. The effect of stent material and the drug-releasing stent material as well as indomethacin itself on cytokine production was studied in THP-1 macrophages. Cytokine production was measured with a protein antibody array. The effect of the stent material was measured on the levels of inflammatory mediators. ELISA was used to confirm the results detected by the protein antibody array and also the effect of indomethacin-releasing stent material and indomethacin itself on the production of cytokines were studied. In an experimental study in rabbits, the new braided pattern PLGA stents appeared to be more biocompatible than metallic stents and also the degradation process of these stents was well controlled. In the pilot clinical study, the insertion of the stents was successful with a new insertion device and all the patients were able to void after the stent had been implanted. In investigation of the drug-eluting properties of