Racial Differences in Paraoxonase-1 (PON1): A Factor in the Health of Southerners?

Abstract

Background:The southern United States (excluding Florida) has the highest age-adjusted rate of cardio vascular disease (CVD) in the country, with African Americans having a higher prevalence of CVD than Caucasians. Paraoxonase-1 (PON1), an enzyme associated with high-density lipoprotein particles, participates both in the hydrolysis of oxidized lipids (thus protecting against atherosclerosis) and in the hydrolysis of organophosphates. Higher paraoxonase activity has been associated with lower risk of atherosclerosis. oBjectives: In this study we characterized the distribution of the functional PON1 Q192R polymorphisms (PON status as assessed by diazoxonase to paraoxonase ratios) and the PON1 activity levels in 200 adult males and females of both races (50 in each race/sex class) from the southern United States from commercially obtained blood bank serum samples. Methods: We used spectrophotometric methods with serum to determine PON1 status, aryl esterase activities (phenyl acetate hydrolysis), and levels of cotinine and C-reactive protein (CRP). results: African Americans had higher paraoxonase activities but lower diazoxonase activities than did Caucasians, consistent with African Americans having a lower proportion of the functional geno type QQ (QQ 15%, QR 34%, RR 44%, 7% indeterminate), than did Caucasians (QQ 60%, QR 31%, RR 7%, 2% indeterminate). Cotinine levels indicated that all samples came from nonsmokers and that CRP levels were higher in African Americans than in Caucasians and higher in females than in males. CRP levels showed no association with paraoxonase activities. conclusions: These data present initial observations for use in characterizing the poorer cardiovascular health status of the population in the southern United States and more specifically southern African Americans. key words: atherosclerosis, cardiovascular disease, C-reactive protein, health disparities. Environ

In Vitro Age-Dependent Enzymatic Metabolism of Chlorpyrifos and Chlorpyrifos-Oxon in Human Hepatic Microsomes and Chlorpyrifos-Oxon in Plasma

“…Plasma samples contained all functional phenotypes of PON1, and the majority was represented by QQ, the phenotype with the lowest CPFoxon hydrolysis activity. The functional phenotype ratio measured here was similar to those reported previously (Albers et al, 2010;Davis et al, 2009), and adult oxon hydrolysis rates were comparable to what others have reported in the literature .…”

“…PON1 Phenotyping. Plasma samples were phenotyped for PON1 status based on functional ratios of diazoxon hydrolysis rates to paraoxon hydrolysis rates (Furlong et al, 1989;Davis et al, 2009;Richter et al, 2009). To measure diazoxon hydrolysis rates, 2 l of plasma were incubated with 200 l of buffer containing 0.1 M Tris-HCl, 2 M NaCl, 2 mM CaCl 2 , and 2 mM diazoxon (8.5 pH).…”

Effect of exercise on plasma paraoxonase1 activity in rugby players: Dependance on training experience

“…This distribution of PON1 Q192R phenotype/genotype with significantly lower frequency of R allele is typical for the Caucasian race, especially in comparison to African race. 28 Considering the uneven PON1 Q192R allele distribution in our study, our observations only suggest but do not have essential power to prove the relationship between PON1 polymorphism and exerciseinduced PON1 activity changes. To our knowledge, the only report on the impact of PON1 polymorphism on its enzymatic activity assayed in connection to acute exercise was published by Tomas et al 17 However, unlike us, the authors determined PON1 genotype, not phenotype.…”

Relationship of human paraoxonase-1 serum activity and genotype with atherosclerosis in individuals from the Deep South

“…Early studies reported that African Americans have a weighted PON1 192Q allele frequency of 0.37 and a weighted PON1 192R allele frequency of 0.63, while Caucasians have a weighted PON1 192Q allele frequency of 0.73 and a weighted PON1 192R allele frequency of 0.27 [27]. A study from our laboratory [28] showed a similar distribution with African Americans having a higher PON1 192R allele frequency, 0.66, and Caucasians having a higher PON1 192Q allele frequency, 0.77.…”