Nanoparticles for delivery of agents to fetal lungs

Abstract

Fetal treatment of congenital lung disease, such as cystic fibrosis, surfactant protein syndromes, and congenital diaphragmatic hernia, has been made possible by improvements in prenatal diagnostic and interventional technology. Delivery of therapeutic agents to fetal lungs in nanoparticles improves cellular uptake. The efficacy and safety of nanoparticle-based fetal lung therapy depends on targeting of necessary cell populations. This study aimed to determine the relative distribution of nanoparticles of a variety of compositions and sizes in the lungs of fetal mice delivered through intravenous and intra-amniotic routes. Intravenous delivery of particles was more effective than intra-amniotic delivery for epithelial, endothelial and hematopoietic cells in the fetal lung. The most effective targeting of lung tissue was with 250nm Poly-Amine-co-Ester (PACE) particles accumulating in 50% and 44% of epithelial and endothelial cells. This study demonstrated that route of delivery and particle composition impacts relative cellular uptake in fetal lung, which will inform future studies in particle-based fetal therapy.

Keywords: Biodegradable nanoparticles; Biodistribution; Fetal therapy; Lung targeting.

Figure 1:. A) IV injection results in greater fetal lung uptake of PLGA NPs than IA injection.

Bar graph showing the percent of DiO positive epithelial, endothelial and hematopoietic lineage cells after e15 IV, e16 IA and e17 IA injection based on flow cytometry, control e16 IA, *, p<0.05, ****, p< 0.0001 (1-way ANOVA. Error bars represent S.D.) n=5-9 B-D) Immunofluorescence images (40x) of fetal lungs after 250 nm PLGA NP delivery via B) e15 IV injection, C) e16 IA injection and D) e17 IA injection. Scale bar on images represents 50μm.

Figure 2:. Polymer type, size and surface modification impact NP delivery to lung after e15 IV injection.

A) Bar graph showing the percent of DiO positive total cells after e15 IV injection. 250nm NPs were considered controls. *, p< 0.05, ***, p<0.001, ****, p< 0.0001(1-way ANOVA. Error bars represent S.D.) n=3-9B) Immunofluorescence images (40x) of fetal lungs after e15 IV injection of 150 nm PLGA NPs C) 250 nm PLGA NPs D) 150 nm PLA-PEG NPs E) 250 nm PACE NPs F) 150 nm PACE-PEG NPs. Scale bar on images represents 50μm.

Figure 3:. NP size, polymer type and surface modification affect NP delivery to different populations of lung cells after e15 injection

Bar graphs showing graph showing the percent of DiO positive cells after injection with A-D) different size NPs (unpaired student’s t-test, Error bars represent S.D.) E-H) 150nm PEGylated and non-PEGylated particles (1-way ANOVA. Error bars represent S.D.) and I-L) 250 NPs with different surface charges (unpaired student’s t-test, Error bars represent S.D.) total cells after e15 IV injection. 250nm NPs were considered controls. *, p< 0.05, **, p<0.01,***, p<0.001,****, p< 0.000, n=3-9

Figure 4:. IA delivery of NP to fetal lung is not improved by altering NP type or pharmacologic manipulation.

A&B) Bar graphs of flow cytometry for % DiO NP uptake of NPs of different compositions and characteristics in all cells, epithelial, endothelial and hematopoietic cells following IA injections at A) e16 and B) e17 (1-way ANOVA. Error bars represent S.D.). In an attempt to augment fetal breathing, theophylline, but no narcotic, was administered. C&D) Bar graphs comparing 250 nm PLGA NPs in epithelial, endothelial and hematopoietic cells by flow cytometry following C) e16 and D) e17 IA injection without theophylline and with narcotic exposure (control) and with theophylline and without narcotic. n=9-11. *, p< 0.05 (Unpaired student’s t-test, error bars represent S.D.)