ABSTRACT
Oxidative stress is an important risk factor for cardiovascular diseases. Although a variety of genetic factors are assumed to contribute to the regulation of oxidative stress, evidence in human populations is insufficient. In this study, we therefore evaluated the effects of six functional single-nucleotide polymorphisms (SNPs) on the oxidative stress under a cross-sectional study design. Participants of the health examination in two neighboring counties were recruited in a mountainous region of Shimane prefeture, Japan (n=1092). As a marker for the oxidative stress, the urinary 8-isoprostane (IsoP) was measured by ELISA. The six SNPs were genotyped using the Taqman method. None of the SNPs showed a significant effect on the IsoP level. However, the Generalized Multiple Dimensionality Reduction (GMDR) method identified that the combination of the two SNPs, MTHFR C677T and eNOS T-786C, showed a significant effect on the IsoP level in this population. The linear regression analysis confirmed that the high risk genotype identified in the GMDR was an independent factor influencing the IsoP even after adjustment of confounding factors. This result suggested that GMDR analysis might be useful to identify concealed effects of combined SNPs.
Subject(s)
Dinoprost/analogs & derivatives , Polymorphism, Single Nucleotide , 1-Alkyl-2-acetylglycerophosphocholine Esterase/genetics , Aged , Amino Acid Substitution , Aryldialkylphosphatase/genetics , Biomarkers/urine , Cross-Sectional Studies , Dinoprost/urine , Female , Genetic Association Studies , Genotype , Humans , Japan , Linear Models , Male , Methylenetetrahydrofolate Reductase (NADPH2)/genetics , NADPH Oxidases/genetics , Nitric Oxide Synthase Type III/genetics , Oxidative Stress , Rural Population , Sequence Analysis, DNAABSTRACT
BACKGROUND: Microangiopathy-related cerebral damage (MARCD) is an entity of cerebrovascular disease based on arteriosclerosis in deep white matter, which includes lacunar infarction and white matter hyperintensity (WMH). As asymmetric dimethylarginine (ADMA), an endogenous inhibitor of the nitric oxide (NO) synthases, and homocysteine are both potential risk factors for arteriosclerosis, the plasma levels of these two substances were evaluated in individuals with MARCD. METHODS: Consecutive participants of a health examination (401 males and 311 females) were recruited for this cross-sectional study. All participants received an magnetic resonance imaging examination, and those with either lacunar infarction or WMH (grade > or =2) were classified into MARCD (+) (N = 146). The plasma ADMA concentration was measured with high performance liquid chromatography. The total homocysteine (tHcy) concentration was measured using a commercial kit. RESULTS: The ADMA level (P < 0.001), symmetric dimethylarginine (SDMA) level (P < 0.05) and L-arginine (Arg)/ADMA ratio (P < 0.01) differed significantly between MARCD (+) and (-) according to nonparametric Wilcoxon test, while the tHcy level did not (P = 0.37). Classic risk factors such as age, blood pressure, and the presence of hypertension differed significantly between the two groups as well. In the logistic analysis, the association of Arg/ADMA with MARCD remained significant (odds ratio and 95% confidence interval, 0.19 (0.05, 0.73), P < 0.05) even after adjusting for the effects of age and hypertension. CONCLUSIONS: ADMA and tHcy levels were studied in 712 subjects with or without MARCD. The Arg/ADMA ratio was suggested to be an independent risk factor for MARCD. A large-scale prospective study is warranted to confirm the causal relationship between Arg/ADMA and MARCD.
