A novel translational model for fetoscopic intratracheal delivery of nanoparticles in piglets.

OBJECTIVES: The aim of this study was to assess the feasibility of fetal tracheal injection in the late-gestational pig to target the airways.
METHODS: Following laparotomy and hysterotomy, fetoscopy was performed in pregnant sows to access the fetal trachea. Two volumes of fluospheres were injected (1 and 3 mL). Fluosphere distribution to the different lung lobes was investigated by microscopy. Possible fetal airway injury, caused by the surgical procedure or intratracheal injection, was investigated. Lung morphology and fetal lung volumes were calculated by micro computed tomography (μCT).
RESULTS: Intratracheal administration was successfully performed in 20/21 fetuses. Analysis by confocal microscopy demonstrated that 3 mL, and not 1 mL, most efficiently targeted all lung lobes. On high-resolution μCT, total airway volume was estimated at 2.9 mL; strengthening that 3 mL is appropriate to target all lung lobes. No procedural damage was evidenced in the lungs or trachea.
CONCLUSIONS: Intratracheal injection of nanoparticles is feasible in the pregnant pig and does not cause procedural lung damage. Using an injection volume of 3 mL, all lung lobes were efficiently targeted. This nanoparticle delivery model to fetal airways opens perspectives for therapeutic interventions.