Measurement and Clinical Significance of Biomarkers of Oxidative Stress in Humans
Oxidative stress has been related to various diseases, gender and ageing, and has been measured by various markers. The authors developed a procedure to compute a global oxidative stress index (OXY-SCORE), reflecting both oxidative and antioxidant markers in healthy subjects. Its performance was tested in relation to age and gender and in coronary artery disease (CAD) patients. Eighty-two healthy subjects and 20 CAD patients were enrolled. Plasma free and total malondialdehyde (F- and T-MDA), glutathione disulphide/reduced form ratio (GSSG/GSH) and urine isoprostanes (iPF2alpha-III) levels were combined as oxidative damage markers (damage score). GSH, alpha- and gamma-tocopherol (TH) levels, and individual antioxidant capacity were combined as antioxidant defence indexes (protection score). The OXY-SCORE was computed by subtracting the protection score from the damage score. Among single parameters, T-MDA and iPF2alpha-III significantly correlated with age; only GSH and both tocopherols correlated with male gender in healthy subjects. The OXY-SCORE was positively associated with age (p=0.004) and male gender (p=0.03). As expected, the OXY-SCORE was higher in CAD with a very significant p-value (<0.0001), after adjusting for age, gender and smoking. Combining different markers can potentially provide a powerful index in the evaluation of oxidative stress related to age, gender and CAD status.