Biomarkers of Oxidative Stress and the Relationship to Cigarette Smoking

Oxidative stress has been implicated in the development of smoking-related diseases such as lung cancer, cardiovascular disease and chronic obstructive pulmonary disease. Damage to biological tissues from interactions with free radicals found within the smoke and induced within cells by smoke exposure, is thought to contribute to smoking-related disease development. Many of these radical components are very short-lived in vivo due to their highly reactive nature and the highly efficient detoxification mechanisms possessed by the body to counteract their effects. Hence, biomarkers are needed to assess the extent of radical exposure and subsequent oxidative damage in humans. Oxidised lipids, proteins and DNA bases persist longer in vivo, and have been extensively investigated as surrogate measures of radical damage. Furthermore, assessment of the body's antioxidant defence mechanisms such as antioxidant enzyme activity and antioxidant compounds can help to understand the extent of radical exposure. This mini review critically evaluates various biomarkers falling into these categories and the consistency of their relationship with smoking status, as a preliminary evaluation of their usefulness in dissecting disease pathways in smokers. The future use of such biomarkers is also briefly discussed.