Abstract
Duodenal mucosal resurfacing (DMR) by thermal ablation of the duodenal mucosa is a minimally invasive endoscopic procedure for controlling metabolic syndrome (MS). However, thermal energy can cause adverse effects due to deep mucosal injury, necessitating an additional mucosal lifting process, which complicate the procedures. Therefore, we aimed to develop a similar procedure using non-thermal photodynamic therapy (PDT) for DMR using a highly functional metal stent covered with photosensitizers (PSs) to minimize the potential risks of thermal ablation injury. We developed a novel PS stent enabling the controlled release of radical oxygen species with specific structures to prevent stent migration and duodenal stricture after ablation and performed an animal study (n = 8) to demonstrate the feasibility and safety of PDT for DMR. The stents were placed for 7 days to prevent duodenal strictures after PDT. To confirm PDT efficacy, we stained for gastric inhibitory polypeptide (GIP) and glucose transporter isoform 1. The PS stents were deployed, and PDT was applied without evidence of duodenal stricture, pancreatitis, or hemorrhage in any of the pigs. Microscopic evaluation indicated apoptosis of the mucosal cells in the irradiated duodenum on days 7 and 14, which recovered after day 28. Immunohistochemistry revealed suppressed GIP expression in the mucosal wall of the irradiated duodenum. Endoscopic PDT for DMR using PS stents could be applied safely in a porcine model and may result in decreased GIP secretion, which is a crucial mechanism in MS treatment. Further clinical studies are required to explore its safety and efficacy in patients with MS.