Influence of the human paraoxonase polymorphism (PON1 192) on the carotid-wall thickening in a healthy population.

ABSTRACT

BACKGROUND: Serum paraoxonase (PON1) is a high-density lipoprotein-bound enzyme that can prevent oxidation of low-density lipoprotein and thus exert an anti-atherogenic effect. A polymorphism at codon 192 (Gln/Arg) of the PON1 gene gives rise to two isoforms that differ in substrate-dependent activity. OBJECTIVE: To determine any independent contribution of this polymorphism to the variability of intimal-medial thickness (IMT) of the common carotid artery for a sample of asymptomatic adult subjects from southern Italy by ultrasonography. METHODS: We studied 196 unrelated asymptomatic subjects (mean age 55.1 years), drawn from participants in a cardiovascular-disease-prevention campaign. Plasma levels of lipids and glucose were measured by routine methods. PON1 polymorphism was determined by polymerase chain reaction. IMT was measured from high-resolution B-mode echo-Doppler ultrasonography images. RESULTS: Prevalences of alleles A (Gln) and B (Arg) were 0.68 and 0.32, respectively. We found no significant difference with regard to plasma levels of lipids and glucose and other variables among the PON1 genotypes, although subjects with BB had higher levels of triglycerides and lower levels of high-density lipoprotein cholesterol. Common carotid artery IMT was slightly greater in subjects with BB, although no significant association between PON1 genotypes and common carotid artery IMT was found, even after adjustment for confounding variables. CONCLUSIONS: Our findings demonstrate that there is no significant association between PON1 gene polymorphism at codon 192 and common carotid artery IMT for an Italian population. However, the fact that we found slightly greater IMT in subjects with genotype BB would suggest that the study should be performed again with a larger sample.