The effect of the trolox equivalent antioxidant capacity (TEAC) in plasma on the formation of 4-aminobiphenylhaemoglobin adducts in smokers

Abstract

Smokers are exposed to a number of carcinogenic compounds including aromatic amines such as 4-aminobiphenyl. Antioxidants are thought to be involved in the defence against the damaging effect of such carcinogens. Recently it has been shown that plasma antioxidant status in smokers is diminished compared with non-smokers. In this study we investigated in 40 smokers whether the trolox equivalent antioxidant capacity (TEAC) in plasma could be quantitatively related to exposure to cigarette smoke. The biomarkers 4-aminobiphenylhaemoglobin (4-ABP-Hb) adduct and cotinine were determined as indices of cigarette smoke exposure. A correlation between 4-ABP-Hb adduct levels and plasma cotinine levels was found for the whole population studied, who smoked 4-70 cigarettes per day (n = 40, r2 = 0.12, p = 0.03). A significant inverse relationship was found between TEAC and 4-ABP-Hb levels (n = 40, r2 = 0.17, p = 0.008). Multiple regression analysis showed a strong relationship between 4-ABP-Hb levels and plasma TEAC and cotinine levels (n = 40, r2 =0.29, p = 0.002). These findings provide strong evidence that the 4- ABP-Hb adduct represents a valuable biomarker of (internal) exposure to tobacco smoke, and also that the formation of this marker is dependent on the plasma antioxidant status. The multiple regression analysis results show that the measure of effect (4-ABP-Hb adduct formation) is largely determined by dose (cotinine) and protection (TEAC).