Use of toxicogenomics for identifying genetic markers of pulmonary oedema

A novel application for Cocoacrisp protein as a biomarker for experimental pulmonary fibrosis

Pulmonary fibrosis is a debilitating disease affecting up to 2 million people worldwide, with a median survival rate of only 3 years after diagnosis. The aim of this study was to evaluate a potential protein biomarker (Cocoacrisp, CC) to identify the onset of pulmonary fibrosis. A model of fibrosis was induced via intratracheal instillation of bleomycin, and samples were collected during the early phase of the disease. Immunohistochemical identification of CC was carried out in lung tissue from the bleomycin model. Quantification by image analysis showed CC levels were doubled (p <0.0003), after a single bleomycin dose, but not after double instillation. Microscopic analysis revealed that CC signal was primarily detected on the alveolar surface. The secretion of the novel protein CC during the early stages of bleomycin-induced injury may have the potential to be utilized as a clinical biomarker for the early stages of fibrosis, particularly as it may be detectable in bronchoalveolar lavage fluid.

Genomic biomarkers of pulmonary exposure to tobacco smoke components

BACKGROUND

Associations between smoking and the development of tobacco-related diseases in humans have historically been assessed by epidemiological studies. These studies are further complicated by the number of chemicals used in tobacco and individual smoking habits. An alternative approach is required to assess the biological responses.

OBJECTIVE

Toxicogenomics was carried out to identify early molecular markers for events in pulmonary injury resulting from tobacco smoke components (TSC) exposure.

MATERIALS AND METHODS

EpiAirway-100 cells were exposed at the air/liquid interface to representative particle (nicotine; cadmium) and vapour phase [formaldehyde (FA) and ethyl carbamate] components of cigarette smoke. Microarray technology was used to compare expression profiles of human genes associated with toxicity and drug resistance, from control and TSC-treated respiratory epithelium (n=5/dose).

RESULTS

Using the GEArray 'toxicology and drug resistance' microarray followed by significance analysis of microarray analysis, 42 mRNA transcripts were found to be significantly altered by the TSC exposure. The vapour [ethyl carbamate, FA and particle (nicotine, cadmium)] phase TSC exhibited differential transcriptional responses that could not be attributed to their chemical phase. The transcriptional changes could be classified according to a functional family, where ethyl carbamate, FA and cadmium classified as carcinogens, demonstrated the highest gene homology when compared with the noncarcinogen, nicotine.

DISCUSSION

Analysis of the microarray data and further confirmation (reverse transcriptase-PCR) identified three potential biomarkers for TSC-induced injury. These three genes (CYP7A1, HMOX1 and PTGS1) are highly upregulated and have been linked with mechanistic pathways of disease.

Conventional and toxicogenomic assessment of the acute pulmonary damage induced by the instillation of Cardiff PM10 into the rat lung

There is strong epidemiological evidence of association between PM10 (particulate matter with an aerodynamic diameter less than or equal to 10 microm) and adverse health outcomes including death and increased hospital admissions for cardiopulmonary conditions. Ambient PM10 surrogates such as diesel exhaust particles (DEP), a common component of UK PM10 have been shown to induce lung inflammation in both humans and rodents. To date, few studies have reported on the toxicological response of UK PM10 in experimental animals. This study examines the pulmonary toxicological responses in male Sprague Dawley rats following the intratracheal instillation of Cardiff urban PM10. A mild but significant change in lung permeability was observed in the lung post-instillation of a high (10 mg) dose of the whole PM10 as adjudged by increases in lung to body weight ratio and total acellular lavage protein. Such effects were less marked following instillation of a water-soluble fraction (80% of the total mass) but histological examination showed that lung capillaries were swollen in size with this treatment. In conclusion, conventional toxicological, histological and toxicogenomic studies have indicated that Cardiff PM10 exhibits low bioreactivity in the form of mild permeability changes. Differential gene expression was observed when the lung was treated with whole PM10, containing durable particles, in comparison with the water-soluble fraction of PM10 that was devoid of particles. Such changes were linked to different histopathological events within the lung.