井上 孝

Objectives: Circulating micro (mi)RNA profiles are influenced by various medical conditions, and miRNAs have been examined as potential biomarkers for cancer, cardiovascular disease, and diabetes. However, few studieshave investigated whether circulating miRNAs and cigarette smoking are correlated. Our aim was to determine theassociation between smoking status and expression of various miRNAs in a Japanese population sample.Methods: We conducted a cross-sectional analysis of 526 subjects (219 men and 307 women) aged 39 years and older who had undergone a health examination at a clinic in Yakumo, Hokkaido in August 2012. We used quantitative real-time polymerase chain reaction to determine serum miRNA expression. We then calculated the odds ratios for elevated serum miRNA levels according to smoking status using never-smokers as the reference group.Results: Expression of lethal (let)-7d, miRNA(miR)-150, miR-192, miR-197 and miR320 was significantly higher in current smokers than in never-smokers. Multivariate logistic regression analyses showed that while current smokers were significantly more likely to have elevated serum levels of miRNA let-7d, miR-21, miR-122, miR-146, miR-150, miR-192, miR-197, and miR320 than never-smokers, former smokers had significantly higher odds of having elevated miR-1, miR-146, miR-150, miR-195, and miR-320 levels in their sera.Conclusions: We found that cigarette smoking is associated with elevated expression of various serum miRNAs. Our results suggest that it is necessary to consider the confounding effect caused by smoking when evaluating expression of serum miRNAs for diagnosing pathological conditions.

Background: Asymmetric dimethylarginine (ADMA) is an endogenous inhibitor of endothelium nitric oxide synthase (NOS). ADMA binds to a substrate-binding site of NOS and then inhibits nitric oxide production from vascular endothelial cells. Elevated ADMA levels are a risk factor for cardiovascular disease. Recently, it was reported that plasma ADMA levels were negatively correlated with vegetable and fruit consumption. The purpose of this study was to examine the association between serum levels of carotenoids and serum ADMA levels in Japanese subjects. Methods: We conducted a cross-sectional study of 470 subjects (203 men and 267 women) who attended a health examination in August 2011. Serum levels of several carotenoids were separately measured by high-performance liquid chromatography. Serum ADMA levels were determined by using an enzyme-linked immunosorbent assay kit. Results: In women, the multivariate-adjusted odds ratios (ORs) of elevated serum ADMA levels were significantly decreased in the highest tertile for beta-cryptoxanthin (OR 0.47, 95% CI 0.23-0.95), alpha-carotene (OR 0.39, 95% CI 0.18-0.79), and beta-carotene (OR 0.36, 95% CI 0.17-0.73) compared to the lowest tertile. In men, significantly decreased ORs were observed in the highest tertiles of serum zeaxanthin/lutein (OR 0.23, 95% CI 0.06-0.69) and acarotene (OR 0.26, 95% CI 0.07-0.82), and in the middle and the highest tertiles of serum beta-carotene (OR 0.27, 95% CI 0.09-0.74 and OR 0.20, 95% CI 0.03-0.88, respectively) when the tertile cutoff points of women were extrapolated to men. Conclusions: Higher serum levels of carotenoids, such as alpha-carotene and beta- carotene, may help to prevent elevated serum ADMA levels in Japanese subjects.