In vitro effect of nicotine and cotinine on susceptibility of LDL to oxidation and hemoglobin glycosylation

ABSTRACT

Nicotine, a major component of cigarette smoke, plays an important role in development of cardiovascular disease and lung cancer in smokers. This study was designed to determine the in vitro effects of nicotine and its metabolite, cotinine on the susceptibility of LDL to oxidation and hemoglobin glycosylation. Three different concentrations of each component [10, 15, 25 micro g/ml] were used. The glycosylation rate of hemoglobin in the presence and absence of nicotine and cotinine were measured by colorimetric method. The susceptibility of LDL to in vitro oxidation was assessed by the Regnstrom technique. Our data showed that nicotine and cotinine are inhibitors for Cu[2+]-induced LDL oxidation but also increased the glycosylation rate of hemoglobin. Nicotine at final concentrations of [10, 15, and 25microg/ml] increased the rate of hemoglobin glycosylation by 25%, 32% and 47%, respectively. Cotinine at similar concentrations, also increasd the rate of glycosylation by 8, 10 and 12%, respectively. Based on data obtained in our study, smoking can result in higher levels of hemoglobin glycosylation which in turn increases the risk of cardiovascular diseases