Objective:
Asymmetrical dimethylarginine (ADMA), an endogenous nitric oxide synthase inhibitor, is known as a mediator of endothelial cell dysfunction. Some clinical studies have found evidence that increased plasma ADMA levels are associated with a higher risk of cerebrovascular events. However, studies on the relationship of plasma ADMA to subclinical atherosclerosis have been scarce.
We evaluated the association of ADMA with carotid intima-media thickness (IMT) in population-based samples in Japan.
Methods:
Population-based Japanese samples composed of 313 men aged 40-49 (40s men) from the ERA-JUMP and 732 men aged 60-79 (60s+70s men) from the SESSA were examined with physical examinations, life-style questionnaires, laboratory assessment and IMT using standardized methods. Plasma samples were stored at -80°C, and concentration of ADMA was determined using a validated high-throughput liquid chromatographic-tandem mass spectrometric assay.
The IMTs of the right and left common carotid arteries, the carotid bulbs, and the internal carotid arteries were examined. Statistical associations were evaluated using multiple linear regression models with adjustment for age, body mass index, systolic blood pressure, LDL-cholesterol, HDL-cholesterol, fasting blood glucose, smoking, alcohol intake, medications for hypertension, hyperlipidemia, or diabetes, and
estimated glomerular filtration rate (eGFR)
.
Results:
The average concentrations and standard deviation (SD) of plasma ADMA in men aged 40-49 and 60-79 were 0.39 ± 0.06 and 0.43 ± 0.06 μmol/L, respectively. The mean and SD of IMT in men aged 40-49 and 60-79 were 0.61 ± 0.07 and 0.91 ± 0.20 mm, respectively. Higher level of ADMA was significantly and positively associated with proportion of current smoking both in 40s and 60s+70s men (correlation coefficient: both p <0.001). It was also significantly and positively associated with eGFR in 60s+70s men (p <0.001) but not associated with eGFR in 40s men (p = 0.429). In full adjusted linear regression models, 1 SD increase in ADMA was associated with 0.14mm increase in IMT in 40s men (p=0.01) but only 0.04mm increase in IMT in 60s+70s men (p=0.26).
Conclusions:
Higher level of ADMA was associated with more IMT independently of traditional risk factors and renal function in young adult men, but not in elderly men.
Assessment of carotid intima-media thickness in patients with type 2 diabetes mellitus and arterial hypertension
