Exogenous Surfactant Enhances the Delivery of Recombinant Adenoviral Vectors to the Lung

Abstract

Somatic gene therapy for pulmonary diseases must be accomplished in vivo, requiring the spread of a gene transfer vector across a vast expanse of respiratory epithelium. Surfactant, a naturally occurring protein and lipid mixture used to treat the respiratory distress syndrome of prematurity, disperses rapidly and evenly throughout the lung. We employed exogenous bovine surfactant (Survanta beractant) as a carrier vehicle for pulmonary delivery of a recombinant adenovirus expressing beta-galactosidase (beta-Gal). Rats treated with an adenovirus-beractant mixture demonstrated more uniform lobar distribution of transgene expression than rats treated with the same amount of virus in saline. Tissue homogenates were examined for quantitative beta-Gal expression by reaction with o-nitrophenol beta-n-galactopyranoside (ONPG). The degree of beta-Gal activity was affected by both the volume and type of carrier used to deliver the virus. At low volumes (0.5 ml, 1.3 ml/kg), beractant-treated animals demonstrated significantly greater pulmonary beta-Gal activity than saline-treated animals (p < 0.002) and untreated controls. At high volume (1.2 ml, 4 ml/kg), average beta-Gal activity was similar between groups treated with beractant or saline, but was more variable within the saline treated group. Higher volumes of delivery medium were associated with increased levels of beta-Gal expression regardless of the carrier used. Survanta was well tolerated by the animals and did not affect the duration of transgene expression. Exogenous beractant provides a useful medium for delivering recombinant adenoviruses to the lung when diffuse distribution of transgene expression is desired.

The effect of synthetic surfactant Exosurf on gene transfer in mouse lung in vivo

“…The surface active properties of surfactant can lead to rapid dispersion of substances in the air spaces and greater volumes of material administered to the airways in surfactant are better tolerated by mice than DNA delivered in either saline 21 or sterile water (personal observation). Improved distribution and an approximate 50% increase in the expression of ␤-galactosidase gene has been reported after endobronchial transfer of replicationdeficient adenovirus resuspended in either bovine surfactant (Survanta Beractant; Ross Products Division of Abbott, Abbott Park, IL, USA) or Exosurf when compared with the same virus suspended in saline.…”

“…Improved distribution and an approximate 50% increase in the expression of ␤-galactosidase gene has been reported after endobronchial transfer of replicationdeficient adenovirus resuspended in either bovine surfactant (Survanta Beractant; Ross Products Division of Abbott, Abbott Park, IL, USA) or Exosurf when compared with the same virus suspended in saline. 21 These surfactant preparations also were reported to facilitate adenovirus-mediated expression of luciferase gene in the peripheral lung in rabbits. 20 However, there has been no data analyzing the effect of a surfactant on the expression of a gene delivered with a naked plasmid DNA in vivo.…”

“…3,11,14 Exogenous pulmonary surfactant has been reported to enhance adenovirus-mediated luciferase gene expression in rabbits 20 and improve the uniformity of ␤-galactosidase expression of replication-deficient adenovirus in rats. 21 Natural pulmonary surfactant is a combination of lipids, proteins and carbohydrates that provide alveolar stability at low lung volumes. 22 A synthetic, protein-free form of surfactant has also been developed and used for replacement therapy in the course of respiratory distress syndrome (RDS).…”

Imaging the spatial distribution of transgene expression in the lungs with positron emission tomography

“…15,[25][26][27] However, the experimental evidence supporting this perception is without strong scientific support. Whereas an increase in gene transfer efficiency may be obtained with surfactantbased vehicles when a low volume of delivery medium is used, 27 the superiority of surfactant over saline-based vehicles was not found at higher delivery volumes (4 ml/kg of b.w.). 27 In addition, numerous other factors may interfere with the efficiency of vehicle delivery (eg lung instillation technique, surfactant concentration in the vehicle, etc).…”

Suppression of Mannheimia (Pasteurella) haemolytica serovar 1 infection in lambs by intrapulmonary administration of ovine antimicrobial anionic peptide

“…Ovine pulmonary surfactant was prepared as previously described [7] and used as a diluent for both bacterial inoculum and peptide suspensions to maximize pulmonary spreading of organisms and lesion penetration of the peptide [8,9]. Briefly, lyophilized surfactant (103.20 mg) and ZnCl 2 (0.54 mg) were suspended in saline (412.8 ml) to a final concentration of 0.25 mg/ml, 10 and 140 mM respectively.…”