¹Department of Gene Therapy, Imperial College at the National Heart and Lung Institute, London, UK

²Centre de Recherche, Hôtel-Dieu de Montréal and Department of Medicine, Université de Montréal, Montreal, Quebec, Canada

³Genzyme Corporation, Framingham, MA, USA

Correspondence to: M Stern, Department of Gene Therapy, National Heart and Lung Institute, Manresa Road, London SW3 6LR, UK

Resolution of pulmonary oedema is mediated by active absorption of liquid across the alveolar epithelium. A key component of this process is the sodium-potassium ATPase (Na⁺K⁺-ATPase) enzyme located on the basolateral surface of epithelial cells and up-regulated during oedema resolution. We hypothesised that lung liquid clearance could be further up-regulated by lipid-mediated transfer and expression of exogenous Na⁺K⁺-ATPase cDNA. We demonstrate proof of this principle in a model of high permeability pulmonary oedema induced by intraperitoneal injection of thiourea (2.5 mg/kg) in C57/BL6 mice. Pretreatment of mice (24 h before thiourea) by nasal sniffing of cationic liposome (lipid #67)-DNA complexes encoding the and subunits of Na⁺K⁺-ATPase (160 g per mouse), significantly (P < 0.01) decreased the wet:dry weight ratios measured 2 h after thiourea injection compared with control animals, pretreated with an equivalent dose of an irrelevant gene. whole lung na⁺K⁺-ATPase activity was significantly (P < 0.05) increased in mice pretreated with na⁺K⁺-ATPase cDNA compared both with untreated control animals as well as animals pretreated with the irrelevant gene. Nested RT-PCR on whole lung homogenates confirmed gene transfer by detection of vector-specific mRNA in three of four mice studied 24 h after gene transfer. This demonstration of a significant reduction in pulmonary oedema following in vivo gene transfer raises the possibility of gene therapy as a novel, localised approach for pulmonary oedema in clinical settings such as ARDS and lung transplantation. Gene Therapy (2000) 7, 960-966.

gene therapy; Na⁺K⁺-ATPase; liposome; pulmonary oedema