Local hyperthermia mediated by gold nanoparticle-integrated silicone-covered stent: feasibility and tissue response in a rat esophageal model

BACKGROUND

To assess the feasibility and tissue response of using a gold nanoparticle (AuNP)-integrated silicone-covered self-expandable metal stent (SEMS) for local hyperthermia in a rat esophageal model.

METHODS

The study involved 42 Sprague-Dawley rats. Initially, 6 animals were subjected to near-infrared (NIR) laser irradiation (power output from 0.2 to 2.4 W) to assess the in vitro heating characteristics of the AuNP-integrated SEMS immediately after its placement. The surface temperature of the stented esophagus was then measured using an infrared thermal camera before euthanizing the animals. Subsequently, the remaining 36 animals were randomly divided into 4 groups of 9 each. Groups A and B received AuNP-integrated SEMS, while groups C and D received conventional SEMS. On day 14, groups A and C underwent NIR laser irradiation at a power output of 1.6 W for 2 min. By days 15 (3 animals per group) or 28 (6 animals per group), all groups were euthanized for gross, histological, and immunohistochemical analysis.

RESULTS

Under NIR laser irradiation, the surface temperature of the stented esophagus quickly increased to a steady-state level. The surface temperature of the stented esophagus increased proportionally with power outputs, being 47.3 ± 1.4 °C (mean ± standard deviation) at 1.6 W. Only group A attained full circumferential heating through all layers, from the epithelium to the muscularis propria, demonstrating marked apoptosis in these layers without noticeable necroptosis.

CONCLUSIONS

Local hyperthermia using the AuNP-integrated silicone-covered SEMS was feasible and induced cell death through apoptosis in a rat esophageal model.

RELEVANCE STATEMENT

A gold nanoparticle-integrated silicone-covered self-expanding metal stent has been developed to mediate local hyperthermia. This approach holds potential for irreversibly damaging cancer cells, improving the sensitivity of cancer cells to therapies, and triggering systemic anticancer immune responses.

KEY POINTS

• A gold nanoparticle-integrated silicone-covered self-expanding metal stent was placed in the rat esophagus. • Upon near-infrared laser irradiation, this stent quickly increased the temperature of the stented esophagus. • Local hyperthermia using this stent was feasible and resulted in cell death through apoptosis.

Stenting the Upper/Cervical Oesophagus with a Proximal Deployment Cervical Oesophageal Stent: Technique and Outcomes

INTRODUCTION

Proximal oesophageal stent deployment continues to provide challenges due to the proximity of the upper oesophageal sphincter and the associated subsequent complications such as globus sensation and stent migration. Patients with cervical oesophageal cancer have previously had limited stenting options available to them with a paucity of the literature describing the radiological technique for successfully placing these high-risk stents. In this paper, we present our experience using the Taewoong Niti-S CERVICAL Oesophageal Stent.

MATERIALS AND METHODS

We describe our method for stent deployment highlighting the importance of pre-procedural planning in ensuring an adequate proximal landing zone for the short proximal flare of the stent. Furthermore, we outline how we have adapted our placement technique to incorporate a routine pre-dilatation stage which has optimised retrieval of the proximal to distal deployment system.

RESULTS

We have placed eight cervical oesophageal stents within our institution. Contrast swallows in all the patients following stent deployment have demonstrated free flow of contrast to the stomach with all patients reporting symptomatic relief and no foreign body/globus sensation. There has been one episode of stent migration but no incidence of oesophageal perforation or haemorrhage.

DISCUSSION

Evolution of stenting technique and the properties of the stents themselves are improving accuracy of stent placement in relation to the important landmark of the upper oesophageal sphincter.

CONCLUSION

Stenting of cervical oesophageal malignancy has proved successful in our institution and provided symptom relief for a subset of palliative patients who were previously unable to benefit from oesophageal stenting.