Serum asymmetric dimethylarginine negatively correlates with intima-media thickness in early-onset atherosclerosis

A systematic review of the correlation between serum asymmetric dimethylarginine, carotid atherosclerosis and ischaemic stroke

OBJECTIVE

To investigate the correlation between serum asymmetric dimethylarginine (ADMA) and the risk of ischaemic stroke and carotid atherosclerosis in adults.

METHODS

We systematically searched PubMed, EMBASE, Web of Science and other databases for relevant studies on serum ADMA and ischaemic stroke or carotid atherosclerosis, which were published from December 1980 to December 2019. The quality of the included studies was evaluated according to the Cochrane system evaluation standard. The difference in serum ADMA level between ischaemic stroke and control group was selected as the effect size (standardized mean difference, SMD). The pooled analysis was performed using Review Manager (V.5.3).

RESULTS

According to the selection criteria, thirteen studies were included in the meta-analysis after screening. Nine studies compared ADMA levels between the ischaemic stroke group and healthy control group, involving a total of 1315 and 880 subjects in the two groups, respectively. Pooled effect sizes were calculated using the random-effects model due to the high heterogeneity (I²  = 93%, P < .00001). The level of serum ADMA in patients with ischaemic stroke was significantly higher than that in healthy people (SDM = 0.69, 95% CI [0.32, 1.06], P = .0002). Seven of the thirteen articles compared ADMA levels between the carotid arteriosclerosis group and the healthy control group, with 559 and 330 subjects in the two groups, respectively. The random-effects model was applied due to the high heterogeneity (I²  = 91%, P < .00001). The level of serum ADMA in patients with carotid arteriosclerosis was significantly higher than that in healthy people (SDM = 1.03, 95% CI [0.49, 1.57], P = .0002).

CONCLUSION

The serum ADMA may be related to ischaemic stroke, and it is a risk factor for carotid atherosclerosis.

Dimethylarginines correlate to common carotid artery wall layer dimensions and cardiovascular risk factors in pregnant women with/without preeclampsia: A group comparative study

OBJECTIVES

Asymmetric- and symmetric dimethylarginines (ADMA, SDMA) are elevated in cardiovascular disease (CVD). Preeclampsia is a pregnancy-specific syndrome and is an independent risk factor for subsequent CVD. Aims were to investigate whether ADMA, SDMA levels and l-arginine/ADMA and l-arginine/SDMA ratios during pregnancy and their changes from pregnancy to postpartum are associated to arterial wall layer dimensions and cardiovascular risk factors in women with and without preeclampsia.

STUDY DESIGN

Dimethylarginines were analyzed by LC-MS, and the common-carotid-artery (CCA) intima and media thicknesses were estimated using 22-MHz non-invasive ultrasonography in women with preeclampsia (cases = 48) and normal pregnancies (controls = 58) in similar gestational age, with reassessment one-year postpartum. A thick intima, thin media and high intima/media ratio (I/M) indicates a less healthy arterial wall.

RESULTS

The median age of cases and controls was 30 years. During pregnancy, women with preeclampsia had higher plasma ADMA, SDMA and lower l-arginine/ADMA and l-arginine/SDMA (all p < 0.01) than women with normal pregnancies. Further, ADMA, SDMA, l-arginine/ADMA and l-arginine/SDMA correlated to intima thickness (r_s = 0.33/0.33/-0.33/-0.35 and p < 0.01), I/M (r_s = 0.26/0.28/-0.22/-0.26 and p < 0.05) and mean arterial pressure (MAP) (r_s = 0.43/0.42/-0.39/-0.40 and p < 0.0001). Changes in ADMA, SDMA and l-arginine/SDMA from pregnancy to postpartum correlated to changes in intima thickness (r_s = 0.22/0.32/-0.21 and p < 0.05/<0.01/<0.05), I/M (r_s = 0.22/0.31/0.08 and p < 0.05/<0.01/=0.43) and MAP (r_s = 0.31/0.53/-0.25 and p < 0.01/<0.001/<0.05). No correlations were found for conventional CCA intima-media-thickness.

CONCLUSIONS

Dimethylarginines were associated to signs of adverse effects on arterial wall layer dimensions and cardiovascular risk factors in women with and without preeclampsia, during pregnancy and to their changes from pregnancy up to one-year postpartum.

ADMA: A Key Player in the Relationship between Vascular Dysfunction and Inflammation in Atherosclerosis

Atherosclerosis is a chronic cardiovascular disease which increases risk of major cardiovascular events including myocardial infarction and stroke. Elevated plasma concentrations of asymmetric dimethylarginine (ADMA) have long been recognised as a hallmark of cardiovascular disease and are associated with cardiovascular risk factors including hypertension, obesity and hypertriglyceridemia. In this review, we discuss the clinical literature that link ADMA concentrations to increased risk of the development of atherosclerosis. The formation of atherosclerotic lesions relies on the interplay between vascular dysfunction, leading to endothelial activation and the accumulation of inflammatory cells, particularly macrophages, within the vessel wall. Here, we review the mechanisms through which elevated ADMA contributes to endothelial dysfunction, activation and reactive oxygen species (ROS) production; how ADMA may affect vascular smooth muscle phenotype; and finally whether ADMA plays a regulatory role in the inflammatory processes occurring within the vessel wall.

Arginine Derivatives in Cerebrovascular Diseases: Mechanisms and Clinical Implications

The amino acid L-arginine serves as substrate for the nitric oxide synthase which is crucial in vascular function and disease. Derivatives of arginine, such as asymmetric (ADMA) and symmetric dimethylarginine (SDMA), are regarded as markers of endothelial dysfunction and have been implicated in vascular disorders. While there is a variety of studies consolidating ADMA as biomarker of cerebrovascular risk, morbidity and mortality, SDMA is currently emerging as an interesting metabolite with distinct characteristics in ischemic stroke. In contrast to dimethylarginines, homoarginine is inversely associated with adverse events and mortality in cerebrovascular diseases and might constitute a modifiable protective risk factor. This review aims to provide an overview of the current evidence for the pathophysiological role of arginine derivatives in cerebrovascular ischemic diseases. We discuss the complex mechanisms of arginine metabolism in health and disease and its potential clinical implications in diverse aspects of ischemic stroke.

Homoarginine/ADMA ratio and homoarginine/SDMA ratio as independent predictors of cardiovascular mortality and cardiovascular events in lower extremity arterial disease

Endothelial dysfunction plays a key role in development of atherosclerosis and lower extremity arterial disease (LEAD). Homoarginine, asymmetric dimethylarginine (ADMA) and symmetric dimethylarginine (SDMA) are sensitive markers for endothelial dysfunction and independent risk factors for cardiovascular death. However, homoarginine may influence the proatherogenic effects of ADMA and SDMA suggesting homoarginine/ADMA ratio or homoarginine/SDMA ratio as further predictors for cardiovascular mortality. Therefore, we investigated the predictive value of homoarginine/ADMA ratio and homoarginine/SDMA ratio related to cardiovascular mortality and cardiovascular events in claudicant patients with LEAD. 151 patients with intermittent claudication were included in a prospective observational study (observation time 7.7 ± 2.5 years) with cardiovascular mortality as main outcome parameter and the occurrence of cardiovascular events as secondary outcome parameter. Homoarginine, ADMA and SDMA were measured by high-performance liquid chromatography at baseline. Low homoarginine/ADMA ratio and homoarginine/SDMA ratio were independently associated with higher cardiovascular mortality (HR 2.803 [95% CI 1.178–6.674], p = 0.020; HR 2.782 [95% CI 1.061–7.290], p = 0.037, respectively) and higher incidence of cardiovascular events (HR 1.938 [95% CI 1.015–3.700], p = 0.045; HR 2.397 [95% CI 1.243–4.623], p = 0.009, respectively). We observed that homoarginine/ADMA ratio and homoarginine/SDMA ratio are independent predictors for long-term cardiovascular mortality and events in claudicant patients with LEAD.

Positive correlation of airway resistance and serum asymmetric dimethylarginine (ADMA) in bronchial asthma patients lacking evidence for systemic inflammation

Background

Contribution of nitric-oxide (NO) pathway to the pathogenesis of bronchial asthma (asthma) is ambiguous as NO may confer both protective and detrimental effects depending on the NO synthase (NOS) isoforms, tissue compartments and underlying pathological conditions (e.g. systemic inflammation). Asymmetric dimethylarginine (ADMA) is an endogenous inhibitor and uncoupler of NOS with distinct selectivity for NOS isoforms. In a cross-sectional study, we assessed whether ADMA is an independent predictor of airway resistance (R_aw) in therapy-controlled asthma.

Methods

154 therapy-controlled asthma patients were recruited. ADMA, symmetric dimethylarginine and arginine were quantitated by HPLC with fluorescent detection. Pulmonary function test was done using whole-body plethysmography, quality of life via St. George’s Respiratory questionnaire (SGRQ). Multiple linear regression was used to identify independent determinants of R_aw. The final model was stratified based on therapy control.

Results

Evidence for systemic inflammation indicated by CRP and procalcitonin was lacking in our sample. Log R_aw showed significant positive correlation with log ADMA in the whole data set and well-controlled but not in the not well-controlled stratum (Spearman correlation coefficients: 0.27, p < 0.001; 0.30, p < 0.001; 0.12, p = 0.51 respectively). This relationship remained significant after adjusting for confounders by multiple linear regression (β = 0.22, CI 0.054, 0.383 p = 0.01). FEF 25–75% % predicted and SGRQ Total score showed significant negative while SGRQ Activity score showed significant positive correlation with R_aw in the final model.

Conclusions

Positive correlation between R_aw and ADMA in the absence of systemic inflammation implies that higher ADMA has detrimental effect on NO homeostasis and can contribute to a poor outcome in asthma.

Asymmetric dimethylarginine and symmetric dimethylarginine prospectively relates to carotid wall thickening in black men: the SABPA study

The relationship of both asymmetric (ADMA) and symmetric (SDMA) dimethylarginine with carotid wall thickness is inconclusive especially among black populations. We aimed to compare carotid intima media thickness (cIMT) and dimethylarginine levels in 75 black and 91 white men at baseline and after a 3-year follow-up, and to investigate associations of percentage change in cIMT with percentage change in dimethylarginine levels (ADMA and SDMA). Plasma levels of ADMA and SDMA were determined with a liquid chromatography mass spectrometry method and B-mode ultrasonography was used to determine the cIMT at baseline and follow-up. In black men, mean cIMT (p = 0.79) and ADMA levels (p = 0.67) remained the same, but SDMA levels were lower (p < 0.001) when comparing baseline and follow-up. In white men, cIMT increased (p < 0.001), but both mean ADMA and SDMA levels decreased (p < 0.001) over time. In black men, percentage change in cIMT was positively associated with percentage change in ADMA (R ² = 0.49; β = 0.46; p < 0.001) and percentage change in SDMA (R ² = 0.46; β = 0.41; p < 0.001). These associations were absent in the white men. Despite lower mean SDMA and similar ADMA and cIMT in black men, percentage change in cIMT was independently associated with percentage change in ADMA and percentage change in SDMA. These results suggest an important role for ADMA and SDMA lowering strategies to delay carotid wall thickening, especially in black populations prone to the development of cardiovascular disease.

Positive correlation of airway resistance and serum asymmetric dimethylarginine level in COPD patients with systemic markers of low-grade inflammation

The major feature of COPD is a progressive airflow limitation caused by chronic airway inflammation and consequent airway remodeling. Modified arginase and nitric oxide synthase (NOS) pathways are presumed to contribute to the inflammation and fibrosis. Asymmetric dimethylarginine (ADMA) may shunt L-arginine from the NOS pathway to the arginase one by uncoupling and competitive inhibition of NOS and by enhancing arginase activity. To attest the interplay of these pathways, the relationship between ADMA and airflow limitation, described by airway resistance (R_aw), was investigated in a cohort of COPD patients. Every COPD patient willing to give consent to participate (n=74) was included. Case history, laboratory parameters, serum arginine and ADMA, pulmonary function (whole-body plethysmography), and disease-specific quality of life (St George’s Respiratory Questionnaire) were determined. Multiple linear regression was used to identify independent determinants of R_aw. The final multiple model was stratified based on symptom control. The log R_aw showed significant positive correlation with log ADMA in the whole sample (Pearson’s correlation coefficient: 0.25, P=0.03). This association remained significant after adjusting for confounders in the whole data set (β: 0.42; confidence interval [CI]: 0.06, 0.77; P=0.022) and in the worse-controlled stratum (β: 0.84; CI: 0.25, 1.43; P=0.007). Percent predicted value of forced expiratory flow between 25% and 75% of forced vital capacity showed that significant negative, elevated C-reactive protein exhibited significant positive relationship with R_aw in the final model. Positive correlation of R_aw with ADMA in COPD patients showing evidence of a systemic low-grade inflammation implies that ADMA contributes to the progression of COPD, probably by shunting L-arginine from the NOS pathway to the arginase one.

Elevated Levels of Asymmetric Dimethylarginine (ADMA) in the Pericardial Fluid of Cardiac Patients Correlate with Cardiac Hypertrophy

Background

Pericardial fluid (PF) contains several biologically active substances, which may provide information regarding the cardiac conditions. Nitric oxide (NO) has been implicated in cardiac remodeling. We hypothesized that L-arginine (L-Arg) precursor of NO-synthase (NOS) and asymmetric dimethylarginine (ADMA), an inhibitor of NOS, are present in PF of cardiac patients and their altered levels may contribute to altered cardiac morphology.

Methods

L-Arg and ADMA concentrations in plasma and PF, and echocardiographic parameters of patients undergoing coronary artery bypass graft (CABG, n = 28) or valve replacement (VR, n = 25) were determined.

Results

We have found LV hypertrophy in 35.7% of CABG, and 80% of VR patients. In all groups, plasma and PF L-Arg levels were higher than that of ADMA. Plasma L-Arg level was higher in CABG than VR (75.7±4.6 μmol/L vs. 58.1±4.9 μmol/L, p = 0.011), whereas PF ADMA level was higher in VR than CABG (0.9±0.0 μmol/L vs. 0.7±0.0 μmol/L, p = 0.009). L-Arg/ADMA ratio was lower in the VR than CABG (VR_plasma: 76.1±6.6 vs. CABG_plasma: 125.4±10.7, p = 0.004; VR_PF: 81.7±4.8 vs. CABG_PF: 110.4±7.2, p = 0.009). There was a positive correlation between plasma L-Arg and ADMA in CABG (r = 0.539, p = 0.015); and plasma and PF L-Arg in CABG (r = 0.357, p = 0.031); and plasma and PF ADMA in VR (r = 0.529, p = 0.003); and PF L-Arg and ADMA in both CABG and VR (CABG: r = 0.468, p = 0.006; VR: r = 0.371, p = 0.034). The following echocardiographic parameters were higher in VR compared to CABG: interventricular septum (14.7±0.5 mm vs. 11.9±0.4 mm, p = 0.000); posterior wall thickness (12.6±0.3 mm vs. 11.5±0.2 mm, p = 0.000); left ventricular (LV) mass (318.6±23.5 g vs. 234.6±12.3 g, p = 0.007); right ventricular (RV) (33.9±0.9 cm² vs. 29.7±0.7 cm², p = 0.004); right atrial (18.6±1.0 cm² vs. 15.4±0.6 cm², p = 0.020); left atrial (19.8±1.0 cm² vs. 16.9±0.6 cm², p = 0.033) areas. There was a positive correlation between plasma ADMA and RV area (r = 0.453, p = 0.011); PF ADMA and end-diastolic (r = 0.434, p = 0.015) and systolic diameter of LV (r = 0.487, p = 0.007); and negative correlation between PF ADMA and LV ejection fraction (r = -0.445, p = 0.013) in VR.

Conclusion

We suggest that elevated levels of ADMA in the PF of patients indicate upregulated RAS and reduced bioavailability of NO, which can contribute to the development of cardiac hypertrophy and remodeling.

Plasma arginine/ADMA ratio as a sensitive risk marker for atherosclerosis: Shimane CoHRE study

BACKGROUND

Asymmetric dimethylarginine (ADMA), which acts an endogenous inhibitor of nitric oxide synthase (NOS), is involved in the pathogenesis of cardiovascular disease. Arginine (Arg) may regulate vascular endothelial function, since Arg is the substrate of NO competing with ADMA. In our previous study, low Arg/ADMA ratio is an independent risk for microangiopathy-related cerebral damage.

PURPOSE

Here, we performed a cross-sectional study to evaluate the association between the Arg/ADMA ratio and the maximal intima-media thickness (IMT) in the carotid artery.

SUBJECTS AND METHODS

Participants were 785 community-dwelling Japanese people without any severe disorders. Plasma concentration of Arg and ADMA in fasting blood sample was determined using HPLC. IMT was measured in the bilateral carotid artery by ultrasonography.

RESULTS

Among quartiles stratified by the Arg/ADMA ratio, ANOVA showed a significant difference in IMT and the IMT in Q1 (the lowest quartile) was significantly higher than that in Q4 (the highest quartile). In multiple linear regression analysis, age, the male gender, lower BMI, the presence of hypertension and lower Arg/ADMA ratio were independently correlated with IMT, while IMT was not correlated with Arg or ADMA alone. In addition, the Arg/ADMA ratio was associated with IMT independent of age, sex, BMI and the presence of hypertension with odds ratio 0.21 (95%CI: 0.05-0.88) in multiple logistic regression analysis for IMT 1.5 mm or more.

CONCLUSION

Imbalance of Arg and ADMA is independently involved in the progression of atherosclerosis, and the Arg/ADMA ratio may be a sensitive marker for atherosclerosis.

The L-arginine pathway in acute ischemic stroke and severe carotid stenosis: temporal profiles and association with biomarkers and outcome

BACKGROUND

Endothelial dysfunction is associated with increased levels of asymmetric dimethylarginine (ADMA) and symmetric dimethylarginine (SDMA) resulting in a decreased production of nitric oxide, which regulates the vascular tone.

METHODS

Patients with acute ischemic stroke (AIS, n = 55) and asymptomatic significant carotid stenosis (AsCS, n = 44) were prospectively investigated. L-arginine, ADMA, SDMA, S100 B, and high-sensitivity C-reactive protein (hsCRP) were serially measured within 6 hours after the onset of stroke, at 24 and 72 poststroke hours. All markers were compared with healthy subjects (n = 45). The severity of AIS was daily assessed by National Institute of Health Stroke Scale scoring.

RESULTS

Even within 6 hours after the onset of stroke, L-arginine, ADMA, and SDMA were significantly higher in patients with AIS compared with both AsCS and healthy subjects. S100 B reflecting infarct size, positively correlated with the level of SDMA at 72 poststroke hours; changes in concentration of S100 B positively correlated with changes in the concentration of ADMA by 72 hours. Change in concentration of both ADMA and SDMA correlated with the change in concentration of hsCRP. Concentrations of L-arginine and hsCRP at 72 poststroke hours, respectively, were independent predictors of poststroke infection. S100 B level measured within 6 hours after the onset of AIS and hsCRP at 72 poststroke hours were independent predictors of death.

CONCLUSIONS

Metabolites of the L-arginine pathway were elevated in the very acute phase of ischemic stroke indicating a more pronounced endothelial dysfunction compared with AsCS. An increased basal L-arginine level in patients with AIS might be an adaptive mechanism; such transient elevation of the L-arginine/ADMA ratio at 24 poststroke hours may suggest that a temporary increase of L-arginine along with decrease of ADMA might be related to the protective role of L-arginine. Changes in the L-arginine pathway are predictive of poststroke infections.

Association of circulating levels of asymmetric dimethylarginine (ADMA) with carotid intima-media thickness: evidence from 6168 participants

BACKGROUND

Epidemiologic investigations have linked the circulating levels of asymmetric dimethylarginine (ADMA), an endogenous inhibitor of nitric oxide synthase (NOS), to carotid intima-media thickness (IMT). However, these studies result in various extent of relation between ADMA and IMT, the conclusions were inconsistent, and the precise relationship is therefore under debate. The objective of this systematic review and meta-analysis is to provide an overview of the relevant studies evaluating the association of levels of ADMA with carotid IMT and to gain more robust estimate of the relationship.

METHODS

Studies were identified through PubMed, Cochrane Library, Embase, reviews, and reference lists of relevant papers. Weighted means of the correlation coefficient (R) and partial correlation coefficient (PR) were calculated for relations by using random-effect models.

RESULTS

22 studies with a total of 6168 subjects were included in our meta-analysis. In an overall pooled estimate of correlation coefficient (R), levels of ADMA were significantly related to carotid IMT (pooled R: 0.29; 95% confidence interval [CI]: 0.20-0.38, P<0.001). Pooled estimate of partial correlation coefficient (PR) also resulted in a significant association of ADMA with carotid IMT (pooled PR: 0.21; 95% CI: 0.14-0.29; P<0.001). Furthermore, subgroup analysis found that the relation between ADMA and IMT was stronger in patients with chronic kidney diseases (CKDs) than that in subject with normal renal function.

CONCLUSIONS

Circulating levels of ADMA were positively related to carotid IMT, especially in patients with CKDs. The findings need confirmation in longitudinal and interventional studies.

Asymmetric dimethyarginine as marker and mediator in ischemic stroke

Asymmetric dimethylarginine (ADMA), an endogenous nitric oxide synthase (NOS) inhibitor, is known as mediator of endothelial cell dysfunction and atherosclerosis. Circulating ADMA levels are correlated with cardiovascular risk factors such as hypercholesterolemia, arterial hypertension, diabetes mellitus, hyperhomocysteinemia, age and smoking. Accordingly, clinical studies found evidence that increased ADMA levels are associated with a higher risk of cerebrovascular events. After the acute event of ischemic stroke, levels of ADMA and its analog symmetric dimethylarginine (SDMA) are elevated through augmentation of protein methylation and oxidative stress. Furthermore, cleavage of ADMA through dimethylarginine dimethylaminohydrolases (DDAHs) is reduced. This increase of dimethylarginines might be predictive for adverse clinical outcome. However, the definite role of ADMA after acute ischemic stroke still needs to be clarified. On the one hand, ADMA might contribute to brain injury by reduction of cerebral blood flow. On the other hand, ADMA might be involved in NOS-induced oxidative stress and excitotoxic neuronal death. In the present review, we highlight the current knowledge from clinical and experimental studies on ADMA and its role for stroke risk and ischemic brain injury in the hyperacute stage after stroke. Finally, further studies are warranted to unravel the relevance of the close association of dimethylarginines with stroke.

Increased production of asymmetric dimethylarginine (ADMA) in ankylosing spondylitis: association with other clinical and laboratory parameters

OBJECTIVE

Asymmetric dimethylarginine (ADMA) has been associated with atherosclerosis, vascular diseases and, recently, also with arthritis including rheumatoid arthritis (RA) and ankylosing spondylitis (AS).

METHODS

Serum ADMA, arginine and symmetric dimethylarginine (SDMA) levels were assessed by liquid chromatography in 61 AS and 26 osteoarthritis (OA) patients with no known cardiovascular disease.

RESULTS

Serum ADMA levels were significantly increased in AS compared to OA patients (0.95 ± 0.17 μM versus 0.70 ± 0.25 μM; p < 0.001). There were no differences in serum arginine and SDMA levels. Serum ADMA levels also positively correlated with age (R = 0.258; p = 0.043), body mass index (R = 0.368; p = 0.003), erythrocyte sedimentation rate (R = 0.329; p = 0.009) and ADMA levels negative correlated with chest expansion (R = -0.251; p = 0.04). No correlations were found between ADMA levels and disease duration, pain intensity, BASDAI, BASFI, BASMI, quality of life, CRP, HLA-B27 positivity, endothelial dysfunction or carotid atherosclerosis.

CONCLUSION

ADMA may serve as a marker of systemic inflammation and may reflect functional immobility in AS. Further studies are needed to assess the possible role of ADMA in AS and AS-related vascular disease.

Methods and potential biomarkers for the evaluation of endothelial dysfunction in chronic kidney disease: a critical approach

The impressive cardiovascular morbidity and mortality of chronic kidney disease (CKD) patients is attributable in a significant proportion to endothelial dysfunction (ED), arterial stiffness, and vascular calcifications. Abnormal vascular reactivity in these patients is more pronounced compared with other high-risk populations, but remains undiagnosed in the usual clinical setting. We briefly review the most important causes and risk factors of ED, oxidative stress, and inflammation related to arterial stiffness. We describe the main methods of ED investigation and the importance of using potential biomarkers together with classic techniques for a more comprehensive assessment of this condition. These methods include evaluation of: forearm blood flow by plethysmography, skin microcirculation by laser Doppler, and flow-mediated vasodilation by Doppler ultrasound imaging. Applanation tonometry is an easy-to-handle tool that allows a clinically reliable assessment of arterial stiffness and is also useful in quantifying endothelium-dependent and -independent vascular reactivity. We also discuss the diagnostic and therapeutic impact of new markers of ED in the CKD population. Improvement of endothelial function is an important challenge for clinical practice, and there are relatively few therapeutical strategies available. Therefore, a combined biomarker and bedside investigational approach could be a starting point for developing optimal therapeutic tools.

Association of the endogenous nitric oxide synthase inhibitor ADMA with carotid artery intimal media thickness in the Framingham Heart Study offspring cohort

BACKGROUND AND PURPOSE

Higher plasma concentrations of the endogenous nitric oxides synthase inhibitor asymmetrical dimethylarginine (ADMA) are associated with increased risk of cardiovascular and cerebrovascular events and death, presumably by promoting endothelial dysfunction and subclinical atherosclerosis. We hypothesized that plasma ADMA concentrations are positively related to common carotid artery intimal-media thickness (CCA-IMT) and to internal carotid (ICA)/bulb IMT.

METHODS

We investigated the cross-sectional relations of plasma ADMA with CCA-IMT and ICA/bulb IMT in 2958 Framingham Heart Study participants (mean age, 58 years; 55% women).

RESULTS

In unadjusted analyses, ADMA was positively related to both CCA-IMT (beta per SD increment, 0.012; P<0.001) and ICA/bulb IMT (beta per SD increment, 0.059; P<0.001). In multivariable analyses (adjusting for age, sex, systolic blood pressure, antihypertensive treatment, smoking status, diabetes, BMI, total-to-HDL cholesterol ratio, log C-reactive protein, and serum creatinine), plasma ADMA was not associated with CCA-IMT (P=0.991), but remained significantly and positively related to ICA/bulb IMT (beta per SD increment, 0.0246; P=0.002).

CONCLUSIONS

In our large community-based sample, we observed that higher plasma ADMA concentrations were associated with greater ICA/bulb IMT, but not with CCA-IMT. These data are consistent with the notion that ADMA promotes subclinical atherosclerosis in a site-specific manner, with a greater proatherogenic influence at known vulnerable sites in the arterial tree.

Endogenous nitric oxide synthase inhibitors, arterial hemodynamics, and subclinical vascular disease: the PREVENCION Study

Endogenous NO synthase inhibitors (end-NOSIs) have been associated with cardiovascular risk factors and atherosclerosis. In addition, end-NOSIs may directly cause hypertension through hemodynamic effects. We aimed to examine the association between end-NOSI asymmetrical dimethylarginine (ADMA) and N-guanidino-monomethyl-arginine (NMMA), subclinical atherosclerosis, and arterial hemodynamics. We studied 922 adults participating in a population-based study (PREVENCION Study) and examined the correlation between end-NOSI/L-arginine and arterial hemodynamics, carotid-femoral pulse wave velocity, and carotid intima-media thickness using linear regression. ADMA, NMMA, and L-arginine were found to be differentially associated with various classic cardiovascular risk factors. ADMA and NMMA (but not L-arginine) were significant predictors of carotid intima-media thickness, even after adjustment for cardiovascular risk factors, C-reactive protein, and renal function. In contrast, ADMA and NMMA did not predict carotid-femoral pulse wave velocity, blood pressure, or hemodynamic abnormalities. Higher L-arginine independently predicted systolic hypertension, higher central pulse pressure, incident wave amplitude, central augmented pressure, and lower total arterial compliance but not systemic vascular resistance or cardiac output. We conclude that ADMA and NMMA are differentially associated with cardiovascular risk factors, but both end-NOSIs are independent predictors of carotid atherosclerosis. In contrast, they are not associated with large artery stiffness, hypertension, or hemodynamic abnormalities. Our findings are consistent with a role for asymmetrical arginine methylation in atherosclerosis but not in large artery stiffening, hypertension, or long-term hemodynamic regulation. L-arginine is independently associated with abnormal pulsatile (but not resistive) arterial hemodynamic indices, which may reflect abnormal L-arginine transport, leading to decreased intracellular bioavailability for NO synthesis.

Stroke in chronic renal failure

Chronic kidney diseases and cardiovascular diseases have several common risk factors like hypertension and diabetes. In chronic renal disease stroke risk is several times higher than in the average population. The combination of classical risk factors and those characteristic of chronic kidney disease might explain this increased risk. Among acute cerebrovascular diseases intracerebral hemorrhages are more frequent than in those with normal kidney function. The outcome of stroke is worse in chronic kidney disease. The treatment of stroke (thrombolysis, antiplatelet and anticoagulant treatment, statins, etc.) is an area of clinical research in this patient group. There are no reliable data on the application of thrombolysis in acute stroke in patients with chronic renal disease. Aspirin might be administered. Carefulness, individual considerations and lower doses might be appropriate when using other treatments. The condition of the kidney as well as other associated diseases should be considered during administration of antihypertensive and lipid lowering medications.