The Effect Of Metallic Stents Covered With A Paclitaxel Incorporated Membrane On Esophagus In Rabbit Models

Background:Esophageal Stent is the most commonly used method of treatment of malignant esophageal strictures. Esophageal stents for malignant Esophageal obstruction are susceptible to occlusion by tumor ingrowth or overgrowth. The only function of these stents is to promote alleviate the malignant dysphagia, they have no antitumor effect.Objective:The aim of this study was to evaluate technical feasibility and the safety of a self-expandable stent covered with a paclitaxel-incorporated membrane in the normal rabbit esophagus.Methods:1. Development of metallic stent covered with paclitaxel-incorporated membrane: The metallic stents were coated with polyurethane containing one of 3 concentrations of paclitaxel (0, 10, and 20 % wt/v) mixed with the polyurethane.2. Animal study: 24 New Zealand white rabbits were chosen and randomly allocated to 3 groups in this study. Stents with each concentration was inserted with flexible Bronchoscopy by an endoscopist gastroenterologist of the rabbits. 2 or 4 weeks after implantation of the stent, the rabbits were killed, and the segment of esophageal containing the stent was examined histologically. 3. In vitro release experiment: To determine the efficacy of the drug release, stents were placed in phosphate buffered saline solution for 12 weeks, and the amount of paclitaxel released was measured by high-performance liquid chromatography.Results:1. All stents were successfully implanted into the desired location of the esophageal of rabbits. No haemorrhage and perforation were observed in any animal. In all groups no migration was observed.2. Inflammatory cell infiltration and erosion were found in the esophageal mucosal epithelium of the paclitaxel-incorporated membrane group. In the Drug-free stents group, tissue reaction and hyperplasia remained obvious 4 weeks after stent insertion. In the paclitaxel-incorporated membrane group, very little hyperplasia was found 4 weeks after the stent insertion.3. In vitro, release of the drug from the paclitaxel-incorporated metallic stent lasted for 3 months.Conclusion:1.Development of paclitaxel-incorporated metallic stent was feasible in design and manufacture.2. Inflammatory damage caused by Paclitaxel coated esophageal stent to the esophageal mucosa was in an acceptable range.3. The Paclitaxel coated esophageal stent possess anti-fibrosis effect.