Measurement of arginine metabolites: regulators of nitric oxide metabolism

Asymmetric Dimethylarginine Is Associated with the Phenomenon of Coronary Slow Flow in Patients with Nonvalvular Atrial Fibrillation

INTRODUCTION

Coronary slow flow phenomena (CSFP) are associated with endothelial and blood component abnormalities in coronary arteries. Asymmetric dimethylarginine (ADMA) can damage the endothelium of the heart or blood vessels in patients with non-valvular atrial fibrillation (NVAF), causing changes in levels of biological indicators. Our aim was to analyze the relationship between ADMA and CSFP in NVAF patients.

METHODS

We consecutively enrolled 134 patients diagnosed with NVAF and underwent coronary angiography, 50 control patients without a history of atrial fibrillation and with normal coronary angiographic flow were included at the same time. Based on the corrected TIMI frame count (CTFC), the NVAF patients were categorized into two groups, CTFC ≤27 frames and CTFC >27 frames. Plasma ADMA, P-selectin (p-sel), von Willebrand factor (vWF), D-dimer (D-Di), plasminogen activator inhibitor 1 (PAI-1), and nitric oxide (NO) were detected by ELISA in the different groups.

RESULTS

We found that plasma ADMA levels were significantly higher among NVAF patients in the CTFC >27 grade group compared with the control or CTFC ≤27 group. In addition, the levels of blood cells and endothelium-related biomarkers (NO, P-selectin, vWF, D-Di, and PAI-1) were significantly altered and correlated with ADMA levels. Multifactorial analysis showed that plasma ADMA (odd ratio [OR; 95% CI]: 1.65 [1.21-2.43], p < 0.001) and left atrial internal diameter (OR [95% CI]: 1.04 [1.02, 1.1], p < 0.001) could be used as independent risk factors for the development of CSFP in patients with NVAF. The ROC curves of ADMA can predict the development of CSFP in NVAF patients. The minimum diagnostic concentration for the development of CSFP in patients was 2.31 µmol/L.

CONCLUSION

Our study demonstrated that CSFP in NVAF patients was associated with high levels of ADMA and left atrial internal diameter. Therefore, aggressive preoperative detection and evaluation of ADMA and left atrial internal diameter can help deal with the intraoperative presence of CSFP.

L-Arginine and SDMA Serum Concentrations Are Associated with Subclinical Atherosclerosis in the Study of Health in Pomerania (SHIP)

Objective

Even though ˪-arginine (ARG) derivatives can predict cardiovascular mortality, their role as atherosclerotic biomarkers is unclear. We tested the hypothesis if asymmetric dimethylarginine (ADMA), symmetric dimethylarginine (SDMA) and the sum of both (DMA) are positively, while ARG and ARG/ADMA ratio are inversely associated with carotid intima-media thickness (cIMT) and atherosclerotic plaque in the carotid artery.

Approach and Results

Cross-sectional data of 1999 subjects (age: 45–81 years; 48.2% ♀) from the population-based Study of Health in Pomerania (SHIP-0) was used. Analysis of variance and logistic regression models were calculated and all adjusted models were corrected for sex, age, smoking status, waist-to-hip ratio and estimated glomerular filtration rate. Increased cIMT (>75^th age-sex specific percentile) was found in 517 subjects (25.7%), while atherosclerotic plaque was detected in 1413 subjects (70.4%). SDMA tertiles were significantly positively associated with larger cIMT among subjects with high SDMA levels [>66^th: 0.82 (95%-CI 0.80; 0.85) mm]. High SDMA levels were related to a higher odds ratio (OR) of increased cIMT [OR 1.39 (95%-CI 1.08; 1.79)]. Furthermore, ARG was positively associated with atherosclerotic plaques [OR 1.41 (95%-CI 1.07; 1.85)]. No relation was found for ADMA and atherosclerosis.

Conclusions

In conclusion, the hypothesis of a positive association between SDMA with an increased cIMT was confirmed. Unexpectedly, ARG was positively related to atherosclerotic plaque. In view of these inconsistent findings, the impact of ARG derivatives as atherosclerotic biomarkers deserves further research.