Stent-based electrode for radiofrequency ablation in the rat esophagus: a preliminary study

Abstract

Endoluminal radiofrequency (RF) ablation has been widely used as a safe and effective treatment for Barrett’s esophagus. However, inadequate RF ablation may occur due to insufficient contact between the electrode and target tissues. Herein, a stent-based monopolar RF electrode (SE) was developed to evenly deliver RF energy to the inner wall of the rat esophagus. The optimal RF parameters were evaluated in the exposed rat esophagus. The temperature in the rat esophagus reached 70 ℃ in 89 s at 30 W, 59 s at 40 W, and 34 s at 50 W. The technical feasibility and efficacy of RF ablation using SE were evaluated based on changes in histological transformation and immunohistochemical parameters of tissues compared at immediately, 1 and 2 weeks after the procedure. The degrees of inflammatory cell infiltration, fibrotic changes, TUNEL, and HSP70 in the RF-ablated rat esophagus were significantly higher than compared with sham control (all p < 0.05). TUNEL-positive deposition gradually decreased, but HSP 70-positive deposition maintained a similar level for 2 weeks. The stent-based RF ablation was technically feasible and effective in evenly inducing thermal damages to the rat esophagus. The RF ablation system using the SE may represent a promising treatment for endoluminal malignancies.

Localized Photodynamic Therapy Using a Chlorin e6-Embedded Silicone-Covered Self-Expandable Metallic Stent as a Palliative Treatment for Malignant Esophageal Strictures

“…Before the in vivo studies, the Ce6-embedded silicone-covered SEMS was pretested in the porcine liver to evaluate the ablation ranges of PDT (Figure and Table S1, Supporting Information). Usually, porcine liver is used to evaluate the ablation ranges, including depth penetration and length of various ablation modalities such as radiofrequency, microwave, laser, high-intensity focused ultrasound, cryoablation, and irreversible electroporation. ,− In our study, although there were structural differences between the esophagus and the liver, we sought to quantitatively evaluate the ablation ranges of localized PDT using the Ce6-embedded silicone-covered SEMS using experiments in liver tissues. The ablation ranges in the liver tissues are shown in Figure A.…”

“…The degree of esophageal tissue injury significantly differed between the groups (all variables, p < 0.001, one-way ANOVA) (Figure I). Localized PDT may induce esophageal strictures; it is well-known that localized ablation modalities such as radiofrequency ablation, irreversible electroporation, microwave, and cryoablation lead to luminal strictures after the procedure. ,,− However, although severe tissue injuries to the PDT-treated esophagus were observed on gross examination, the SEMS was well maintained after the localized PDT procedure, and the placed SEMS may prevent PDT-induced luminal narrowing. Nonetheless, due to its potential to cause necrosis, thermal ablation affects target not only tissues but also normal and/or benign tissues, leading to complications, such as vascular damage, scarring, restenosis, infection, and bleeding with or without perforation. , The Ni–Ti alloy is an important and practical shape-memory alloy with superelasticity and high biocompatibility .…”

Radiofrequency ablation via an implanted self-expandable metallic stent to treat in-stent restenosis in a rat gastric outlet obstruction model

“…Several SEMS-mediated RFA studies were conducted to validate the feasibility and efficacy, and RFA using the SEMS could achieve uniform, circumferential, and transmural coagulative necrosis (Goldberg et al, Frontiers in Bioengineering and Biotechnology frontiersin.org 1997; Byun et al, 2003;Antunes et al, 2010;Won et al, 2022). However, these studies were conducted only in extracted liver or normal animal models.…”