Preclinical Evaluation of Endoscopic Placement of a Steroid-eluting Metal Stent in an In Vivo Porcine Benign Biliary Stricture Model

Abstract

Treatment of benign biliary strictures (BBS) using fully covered self-expandable metal stents (FCSEMS) has a high success rate, but recurrence can occur. Corticosteroids may be useful based on their anti-fibrotic and anti-inflammatory effects. We investigated the safety and efficacy of corticosteroid-eluting FCSEMS in an animal model. BBSs were created by radiofrequency ablation in 12 mini-pigs. Four weeks later, FCSEMS coated with 0 mg (control), 15 mg (steroid 1x group), or 30 mg (steroid 2x group) triamcinolone were inserted endoscopically. The in vitro drug release assay revealed that the optimal stent had 15 mg of triamcinolone and a hydrophilic membrane. No transmural necrosis or perforation occurred in any animal. Fibrous wall thickness tended to decrease macroscopically and microscopically in a triamcinolone dose-dependent manner (control vs. steroid 2x group: 773.1 vs. 468.5 µm, P = 0.037). Thickness also decreased over time in the steroid 2x group (3 days vs. 4 weeks: 907.9 vs. 468.5 µm, P = 0.025). Blood parameters tended to improve after stent insertion. In a porcine BBS model, steroid-eluting FCSEMS showed potential as a safe and effective treatment modality to reduce fibrotic tissue. Studies are required to confirm their safety and efficacy in humans with refractory BBS.

Relationship between postoperative biliary stricture and clinical characteristics of patients with benign and malignant biliary diseases.

“…In terms of imaging manifestations, magnetic resonance cholangiopancreatography (MRCP), computed tomography (CT), B-ultrasound, T-tube radiography, choledochoscopy, duodenoscopy and other imaging examinations and endoscopy have played an important role in the diagnosis and differential diagnosis of postoperative biliary stenosis [8][9][10]. Due to the persistence of stenosis, secondary surgery under endoscopy, direct vision or endoscopy is often required, which not only increases the pain of patients, but also wastes medical resources [11,12].…”