Dexamethasone-eluting and self-expandable biodegradable stents suppress fibrosis in biliary stricture

Aims The aim of this study was to observe the degradation process and therapeutic effect of drug-eluting biodegradable biliary stents (DBBS), and to evaluate sequential changes in their mechanical properties. Methods We made prototype of DBBS with biodegradable sheath-core monofilaments, polydioxanone (PDO) as the outer sheath and poly-L-lactic acid (PLLA) as an inner core, using the cross-and-hook knitting hand-made method. Since the degradation time of PLLA is longer than that of PDO, the PLLA core filament may be exposed after the PDO has partially degraded and thinned. Using an in vitro bile flow phantom model, we evaluated degradation time, radial force changes, and morphologic changes of DBBS. Using an in vivo swine bile duct stricture model, we performed a DPOC examination and histopathologic evaluation to observe the biodegradation process and therapeutic effects of DBBS at regular intervals [ 1 ] [ 2 ] [ 3 ]. Results In the bile flow phantom model, DBBS maintained high radial force and kept their original shape up to 12 weeks. A total of 10 DBBS was inserted into the artificially obstructed bile ducts of 10 swine. In this animal model, DPOC examination revealed that DBBS maintained their original shapes for approximately 10 weeks, and the stricture area disappeared, and the accompanying ulcers completely improved after 10 weeks. On histopathologic examination, the thickness of the fibrosis layer was rapidly decreasing after two weeks, and the mucosa maintained a relatively normal layer during follow-up period. Conclusions This study revealed that DBBS maintained their original shape and radial force for a relatively long time and showed dramatic therapeutic effects. Publication History Article published online: 14 April 2023 © 2023. European Society of Gastrointestinal Endoscopy. All rights reserved. Georg Thieme Verlag KG Rüdigerstraße 14, 70469 Stuttgart, Germany