Efficient intratracheal delivery of airway epithelial cells in mice and pigs

Abstract

Cellular therapy via direct intratracheal delivery has gained interest as a novel therapeutic strategy for treating various pulmonary diseases including cystic fibrosis lung disease. However, concerns such as insufficient cell engraftment in lungs and lack of large animal model data remain to be resolved. This study aimed to establish a simple method for evaluating cell retention in lungs and to develop reproducible approaches for efficient cell delivery into mouse and pig lungs. Human lung epithelial cells including normal human bronchial/tracheal epithelial (NHBE) cells and human lung epithelial cell line A549 were infected with pSicoR-green fluorescent protein (GFP) lentivirus. GFP-labeled NHBE cells were delivered via a modified intratracheal cell instillation method into the lungs of C57BL/6J mice. Two days following cell delivery, GFP ELISA-based assay revealed a substantial cell-retention efficiency (10.48 ± 2.86%, n = 7) in mouse lungs preinjured with 2% polidocanol. When GFP-labeled A549 cells were transplanted into Yorkshire pig lungs with a tracheal intubation fiberscope, a robust initial cell attachment (22.32% efficiency) was observed at 24 h. In addition, a lentiviral vector was developed to induce the overexpression and apical localization of cystic fibrosis transmembrane conductance regulator (CFTR)-GFP fusion proteins in NHBE cells as a means of ex vivo CFTR gene transfer in nonprogenitor (relatively differentiated) lung epithelial cells. These results have demonstrated the convenience and efficiency of direct delivery of exogenous epithelial cells to lungs in mouse and pig models and provided important background for future preclinical evaluation of intratracheal cell transplantation to treat lung diseases.

Stem Cells, Cell Therapies, and Bioengineering in Lung Biology and Diseases 2017. An Official American Thoracic Society Workshop Report

“…They determined that 10% of cultured cells need to have functional CFTR activity to recover function in an Ussing chamber assay, but difficulties remain in achieving a sufficient number of engrafted cells in vivo to recover function. Polidocanol has been used by Dr. Randell’s group and others to regionally strip resident airway cells and provide access to the basement membrane for cellular engraftment ( 41 , 42 ). This is a major step toward improving understanding of how to encourage cell engraftment of exogenously gene-corrected airway cells for patients with CF.…”

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

“…To determine the optimal volume for intratracheal injection, we randomly chose two different volumes 1 and 3 mL ( n = 10/volume), based on data from adult 25 to 30‐kg Yorkshire pigs where a 10‐mL volume of treated cells was intratracheally injected . Immediately post‐surgery and T61 injection, the thoracic cavity was opened, the trachea ligated and the lungs removed from the body.…”

Induced pluripotent stem cells for treating cystic fibrosis: State of the science

“…A human trial is said to be planned. In an alternative to the intravenous injection route, lungs of mice and pigs, whose lungs had been pre‐injured/pre‐conditioned with 2% polidocanol (PDOC), mature human airway epithelial cells were administered intra‐tracheally . Based on a fluorescent label, cell retention/”engraftment” 2 days later was ca.…”

“…In an alternative to the intravenous injection route, lungs of mice and pigs, whose lungs had been pre-injured/pre-conditioned with 2% polidocanol (PDOC), mature human airway epithelial cells were administered intra-tracheally. 121 Based on a fluorescent label, cell retention/ The "pre-injured/pre-conditioned strategy" has also been attempted in studies with direct CF-centric relevance. In an early study with bone marrow (stem) cells (BMC), Wong et al 122 Recalling that transdifferentiation of BMCs was infrequent, nonetheless, apical [wildtype]CFTR protein was detected in the reconstituted airway; P aeruginosa infection was delayed; and survival was increased.…”