Percutaneous in vivo gene transfer to the peripheral lungs using plasmid-liposome complexes

Emerging drugs for idiopathic pulmonary fibrosis

Pulmonary fibrosis is often the end stage of chronic, persistent, low-level lung injury, either of known or unknown cause. The most severe form of pulmonary fibrosis is idiopathic pulmonary fibrosis (IPF), a disease process of unknown aetiology and one that often leads to respiratory failure and death. At present there are no proven or effective drug therapies for IPF. Recent advances in understanding of disease pathogenesis have focused attention on drug targeting of fibrogenic pathways, as opposed to traditional anti-inflammatory approaches. In this report, the present status of drug development of a number of emerging antifibrotic strategies and agents that may prove more effective in the therapy of this progressive, debilitating and fatal disease are reviewed.

Impaired pulmonary inflammatory responses are a prominent feature of streptococcal pneumonia in mice with experimental emphysema

Little is known about why patients with chronic obstructive pulmonary disease are susceptible to bacterial infections. Using an animal model of pulmonary emphysema, we investigated the inflammatory responses to bacterial infection. After intratracheal infection with Streptococcus pneumoniae (10(3)-10(7) cfu/mouse), the control mice did not die. However, the mice with emphysema died in a dose-dependent manner. Bronchoalveolar lavage fluid, examined 24 hours after infection showed that the numbers of total cells and neutrophils, in addition to murine tumor necrosis factor-alpha and macrophage inflammatory protein-2 concentrations, were significantly less in the mice with emphysema compared with the control mice. Histopathologic findings revealed that the alveoli were filled with inflammatory cells and exudate in the control mice but not in the mice with emphysema. Seventy-two hours after infection, serum cytokine levels were significantly higher in the mice with emphysema, and significant numbers of S. pneumoniae were detected in both the whole lung tissues and the blood of mice with emphysema. These findings suggest that the inflammatory response in mice with emphysema was impaired at the site of bacterial infection despite the bacteremia, which accelerated severe systemic inflammatory responses. Accordingly, intra-alveolar but not systemic immune responses to bacterial infection were impaired in the presence of experimental emphysema.

Vehicles for oligonucleotide delivery to tumours

The vasculature of a tumour provides the most effective route by which neoplastic cells may be reached and eradicated by drugs. The fact that a tumour's vasculature is relatively more permeable than healthy host tissue should enable selective delivery of drugs to tumour tissue. Such delivery is relevant to carrier-mediated delivery of genetic medicine to tumours. This review discusses the potential of delivering therapeutic oligonucleotides (ONs) to tumours using cationic liposomes and cyclodextrins (CyDs), and the major hindrances posed by the tumour itself on such delivery. Cationic liposomes are generally 100-200 nm in diameter, whereas CyDs typically span 1.5 nm across. Cationic liposomes have been used for the introduction of nucleic acids into mammalian cells for more than a decade. CyD molecules are routinely used as agents that engender cholesterol efflux from lipid-laden cells, thus having an efficacious potential in the management of atherosclerosis. A recent trend is to employ these oligosaccharide molecules for delivering nucleic acids in cells both in-vitro and in-vivo. Comparisons are made with other ON delivery agents, such as porphyrin derivatives (< 1 nm), branched chain dendrimers (approximately 10 nm), polyethylenimine polymers (approximately 10 nm), nanoparticles (20-1,000 nm) and microspheres (> 1 microm), in the context of delivery to solid tumours. A discourse on how the chemical and physical properties of these carriers may affect the uptake of ONs into cells, particularly in-vivo, forms a major basis of this review.