Asbestos

Biomarkers of Asbestos

There is not an ideal biomarker for asbestos. Exposure to asbestos is most often determined through a written history questionnaire, focusing on work related exposures. X-rays and lung function tests are also common in determining the possibility of asbestos related disease.

X-rays can detect early signs of disease related to asbestos. They may show pleural plaques, pleural calcification, or pleural fibrosis if the person has been exposed. There are two different lung function tests used to determine the health of the lungs: forced vital capacity (FVC) and forced expiratory volume (FEV). FVC is the maximum amount of air expired rapidly after the maximum amount of air has been inhaled. FEV is the FVC measured over 1 second, or another unit of time. Asbestos fibers can be detected in mucus, urine and feces. These do not reflect the burden of asbestos on the lungs. Lung biopsies can be a reliable determination of asbestos exposure, yet they are very invasive, and often only used in autopsies.

Bronchoalveolar lavage fluid samples are sometimes evaluated. This uses a fiber optic bronchoscopy to obtain a small piece of lung tissue. This is a semi-invasive procedure. It is not reliable on dose, or prediction of disease. The sample can be tested for fibronectin, which is a mediator released by macrophages in the presence of asbestos. It can also be tested for procollagen III, where levels increase in those who are exposed. Scientists are also looking into testing for gene expressions of anti-oxidant enzymes, which are occur when asbestos is present. Studies are also looking into biomarkers in blood serum. Studies are pointing to elevated levels of the amino-terminal peptide of procollagen III found in exposed people. Studies are also looking at biomarkers in urine. It has been found that in asbestos workers, there is an increase in the excretion of the oxidative DNA adduct 8-hydroxy-deoxyquanosine, which indicates DNA damage