A pilot animal study of a novel nanocomposite silicone airway stent: biocompatibility and performance in a sheep model

Airway obstruction resulting from both malignant and non-malignant etiologies is a growing challenge in pulmonary diseases and critical care medicine, particularly after the COVID-19 pandemic. Conventional silicone and metallic airway stents may be indicated in airway obstructions that lead to palliative relief, but they may lead to complications such as migration, inflammatory reaction to the adjacent tissue, and granulation tissue overgrowth. We conducted this animal pilot study to investigate the biocompatibility of a next-generation nanocomposite silicone airway stent, engineered with 3wt% hydrophobic nano-silica reinforcement. Innovative characteristics of the stent include improved biocompatibility and reduced mucus adhesion due to its hydrophobic properties. A refined stenting technique was applied to implant the stent in the trachea of two sheep models by assembling two endotracheal tubes, Ambu, and the stent. After a two-month follow-up, high-resolution computed tomography imaging, 3D virtual bronchoscopy, bronchoscopy, and biopsy of the tracheal wall were done. Histopathologic assessment demonstrated an inflammatory infiltrate dominated by lymphocytes, without stromal reactions, mucosal and submucosal thickening, or granulation, confirming a favorable tissue tolerance. These preliminary outcomes emphasize the stent's potential as a transformative therapeutic option; however, the study's limited sample size and absence of comparative controls highlight the necessity for further preclinical trials with quantitative airflow parameters to elucidate the clinical translatability of this innovative biomaterial solution for airway obstructions. Additionally, the findings of this study can address the unmet needs in managing complex airway obstructions, particularly for patients refractory to current therapeutic options in the future.