Biomarker

A biomarker is a substance that is useful in describing a biological state. A study group commissioned by the NIH provided a working definition for biomarker as: "a characteristic that is objectively measured and evaluated as an indicator of normal biologic processes, pathogenic processes, or pharmacological responses to a therapeutic intervention" (1). Organisms both past and present possess molecules that attest to their existence. Fields such as geology, astrobiology, cell biology, and medicine make use of biomarkers on a routine basis. Geochemists and astrobiologists search for biosignatures on Earth and from possible extraterrestrial sources, respectively. Cell biologists utilize biomarkers to determine the location of specific cell types within an organism. Physicians make use of biomarkers in detection, diagnosis, and treatment of any number of disease states.

The exposure to various environmental contaminants can be detected using biomarkers. The fields of toxicology and epidemiology make particular use of biomarkers in this manner. In some instances, the contaminant itself serves as the biomarker. Asbestos particles, for example, can be viewed as biomarkers. A Japanese-U.S. research team recently developed the first test to detect biomarkers that arise from exposure to diesel exhaust (2). In this study, the test was designed to register the presence of diesel exhaust exposure-specific metabolites in urine. Also known as bioindicators, metabolites are forms of compounds that undergo processing by the body following exposure to a substance

It is becoming increasingly important to be able to early detect the magnitude of exposure to contaminants such as asbestos. Epidemiology is concerned with three primary categories for risk assessment studies on biomarkers of fibers and particles (3): biomarkers of exposure, biomarkers of effect, and biomarkers of susceptibility. As such, asbestos is the most well known example of a carcinogen and co-carcinogen. Asbestos fibers and particles are known to be responsible for conditions such as asbestosis, pleural plaques, mesothelioma, and various cancers, with lung cancer being the most prolific killer of them all.

'Biomarker' Sources:
  1. Atkinson, A.J. et al., "Biomarkers and surrogate endpoints: preferred definitions and conceptual framework". Clin. Pharmacol. Ther.; 69:89-95, 2001.
  2. Toriba, A. et al., "Identification and quantification of 1-nitropyrene metabolites in human urine as a proposed biomarker for exposure to diesel exhaust". Chem. Res. Toxicol.; 20:999-1007, 2007.
  3. Bhattacharya, K. et al., "Biomarkers in risk assessment of asbestos exposure". Mutat. Res.; 579:6-21, 2005.




 

 

- A - B - C - D - E - F - G - H - I - L - M - N - O - P - Q - R - S - T - V - W - X