Impact of ADMA, endothelial progenitor cells and traditional cardiovascular risk factors on pulse wave velocity among prediabetic individuals

Association between protein arginine N-methyltransferase 1 polymorphism and overt diabetic nephropathy: Role of asymmetric dimethylarginine in vascular tone

Background

ω-NG,NG-asymmetric dimethylarginine (ADMA) regulates vascular tone and may participate in the pathogenesis of diabetic nephropathy (DN).

Objective

To investigate whether single-nucleotide polymorphisms (SNPs) around the protein arginine N-methyltransferase 1 gene (PRMT1) influence ADMA dynamics and DN incidence and severity.

Methods

This study utilized a hospital-based database containing 310 Japanese patients with type 2 diabetes mellitus (T2DM). The association of PRMT1-related tagged SNPs with DN stage distribution was examined using a dominant model of minor alleles. PRMT1 mRNA, serum ADMA, reactive hyperemia-peripheral arterial tonometry index (RHI), and brachial-ankle pulse wave velocity (baPWV) were compared between the genotype-based subgroups of causal SNP, and correlations between these variables were evaluated.

Results

The composition of DN stages significantly differed between the GG and GA + AA subgroups of rs892151 (p = 0.026). In a propensity-matching cohort of rs892151, the GA + AA subgroup had an increased incidence of overt DN (odds ratio 2.92, 95 % confidence interval 1.12-7.62, p = 0.028), along with higher PRMT1 mRNA, serum ADMA levels, and baPWV than the GG subgroup (p < 0.001, p = 0.023 and 0.047, respectively). There were correlations between PRMT1 mRNA and serum ADMA levels, between serum ADMA levels and RHI, and between baPWV and urinary albumin excretion (r = 0.335, p < 0.001, r = -0.221, p = 0.029, and r = 0.254, p = 0.004, respectively).

Conclusions

T2DM patients carrying the PRMT1-related variant rs892151 were susceptible to overt DN. ADMA-mediated endothelial dysfunction and arterial stiffness may be involved in the variant-related pathogenesis of overt DN.

LncRNA DANCR deficiency promotes high glucose-induced endothelial to mesenchymal transition in cardiac microvascular cells via the FoxO1/DDAH1/ADMA signaling pathway

Cardiac fibrosis is the main pathological basis of diabetic cardiomyopathy (DCM), and endothelial-to-meschenymal transition (EndMT) is a key driver to cardiac fibrosis and plays an important role in the pathogenesis of DCM. Asymmetric dimethylarginine (ADMA), a crucial pathologic factor in diabetes mellitus, is involved in organ fibrosis. This study aims to evaluate underlying mechanisms of ADMA in DCM especially for EndMT under diabetic conditions. A diabetic rat model was induced by streptozotocin (STZ) injection, and human cardiac microvascular endothelial cells (HCMECs) were stimulated with high glucose to induce EndMT. Subsequently, the role of ADMA in EndMT was detected either by exogenous ADMA or by over-expressing dimethylarginine dimethylaminohydrolase 1 (DDAH1, degradation enzyme for ADMA) before high glucose stimulation. Furthermore, the relationships among forkhead box protein O1 (FoxO1), DDAH1 and ADMA were evaluated by FoxO1 over-expression or FoxO1 siRNA. Finally, we examined the roles of LncRNA DANCR in FoxO1/DDAH1/ADMA pathway and EndMT of HCMECs. Here, we found that EndMT in HCMECs was induced by high glucose, as evidenced by down-regulated expression of CD31 and up-regulated expression of FSP-1 and collagen Ⅰ. Importantly, ADMA induced EndMT in HCMECs, and over-expressing DDAH1 protected from developing EndMT by high glucose. Furthermore, we demonstrated that over-expression of FoxO1-ADA with mutant phosphorylation sites of T24A, S256D, and S316A induced EndMT of HCMECs by down-regulating of DDAH1 and elevating ADMA, and that EndMT of HCMECs induced by high glucose was reversed by FoxO1 siRNA. We also found that LncRNA DANCR siRNA induced EndMT of HCMECs, activated FoxO1, and inhibited DDAH1 expression. Moreover, over-expression of LncRNA DANCR could markedly attenuated high glucose-mediated EndMT of HCMECs by inhibiting the activation of FoxO1 and increasing the expression of DDAH1. Collectively, our results indicate that LncRNA DANCR deficiency promotes high glucose-induced EndMT in HCMECs by regulating FoxO1/DDAH1/ADMA pathway.

Relationship between plasma asymmetric dimethylarginine and nitric oxide levels affects aerobic exercise training-induced reduction of arterial stiffness in middle-aged and older adults

Purpose

Aerobic exercise training (AT) reverses aging-induced deterioration of arterial stiffness via increased arterial nitric oxide (NO) production. Asymmetric dimethylarginine (ADMA), an endogenous inhibitor of NO synthase, was decreased by AT. However, whether AT-induced changes in ADMA levels are related to changes in nitrite/nitrate (NOx) levels remains unclear. Accordingly, we aimed to clarify whether the relationship between plasma ADMA and NOx levels affected the AT-induced reduction of arterial stiffness in middle-aged and older adults.

Methods

Thirty-one healthy middle-aged and older male and female subjects (66.4 ± 1.3 years) were randomly divided into two groups: exercise intervention and sedentary controls. Subjects in the training group completed an 8-week AT (60%-70% peak oxygen uptake [V̇O2peak] for 45 min, 3 days/week).

Results

AT significantly increased V̇O2peak (P < 0.05) and decreased carotid β-stiffness (P < 0.01). Moreover, plasma ADMA levels were significantly decreased while plasma NOx levels and NOx/ADMA ratio were significantly increased by AT (P < 0.01). Additionally, no sex differences in AT-induced changes of circulating ADMA and NOx levels, NOx/ADMA ratio, and carotid β-stiffness were observed. Furthermore, the AT-induced increase in circulating ADMA levels was negatively correlated with an increase in circulating NOx levels (r = -0.414, P < 0.05), and the AT-induced increase in NOx/ADMA ratio was negatively correlated with a decrease in carotid β-stiffness (r = -0.514, P < 0.01).

Conclusion

These results suggest that the increase in circulating NOx with reduction of ADMA elicited by AT is associated with a decrease in arterial stiffness regardless of sex in middle-aged and older adults.

ADMA (asymmetric dimethylarginine) and angiogenic potential in patients with type 2 diabetes and prediabetes

Asymmetric dimethylarginine is an endogenous competitive inhibitor of nitric oxide synthase and marker of endothelial dysfunction, but the question remains as to whether asymmetric dimethylarginine is a marker of cardiovascular episodes or their independent risk factor. ADMA/DDAH (dimethylaminohydrolase) pathway regulates vascular endothelial growth factor (VEGF)-mediated angiogenesis due to its impact on the NO formation. The aim of the study was to assess the concentrations of asymmetric dimethylarginine and the angiogenic potential in the blood of subjects with type 2 diabetes (T2DM, n = 33) and patients with prediabetes (n = 32)-impaired fasting glycemia and/or impaired glucose tolerance (WHO criteria). The study found that both the prediabetes group and subjects with T2DM had significantly elevated concentrations of asymmetric dimethylarginine, significantly high levels of VEGF-A, low ratio of sVEGF-R1/VEGF-A, and sVEGF-R2/VEGF-A. This may suggest endothelial damage at early stages of carbohydrate metabolism dysfunction-before T2DM is diagnosed. Higher proangiogenic potential in prediabetes and T2DM patients than in healthy subjects, is not only the effect of an increase in VEGF-A levels, but also reduced inhibition of circulating receptors.

Evaluation of the associations of body height with blood pressure and early-stage atherosclerosis in Chinese adults

Body height has been recently related to the risk of coronary heart disease and metabolic risk factors. However, data are scarce regarding the relationship between body height and early-stage atherosclerotic changes, especially in Chinese individuals. In this study, we aimed to comprehensively examine the associations of body height with early-stage atherosclerosis and blood pressure in Chinese adults. Carotid-femoral pulse wave velocity (cfPWV), carotid-radial pulse wave velocity (crPWV), carotid artery-dorsalis pedis pulse wave velocity (cdPWV), and body height were measured in 5098 men and women. All samples were obtained from a community-based health examination survey in central China. After adjusting for sex, age, weight, fasting glucose level, lipid level, creatinine, and heart rate, low body heights were significantly associated with higher cfPWV, crPWV, and blood pressure (all P for trend <.01), whereas no significant association was found between body height and cdPWV. In addition, we found a significant interaction between prehypertension status and body height in relation to cfPWV, after adjusting for covariates (P for interaction = .0024). The associations were stronger in participants with prehypertension than in those with normal blood pressure. Compared to the group with the tallest stature and normal blood pressure, individuals in the group with the shortest stature and prehypertension had nearly a 2.5 m/s higher cfPWV. These results indicate that short body height was associated with an increased risk of early-stage atherosclerosis in Chinese adults, independent of traditional cardiometabolic risk factors. Prehypertension might modify the association between body height and cfPWV.

Asymmetric dimethylarginine is not a marker of arterial damage in children with glomerular kidney diseases

Introduction

Asymmetric dimethylarginine (ADMA), an endogenous inhibitor of nitric oxide synthase, correlates with cardiovascular risk especially in patients with chronic kidney disease. The aim of our study was to establish significance of ADMA as a biomarker of arterial damage in children with glomerulopathies.

Material and methods

In 80 children with glomerulopathies (mean age, 11.33 ±4.25 years; 42 with idiopathic nephrotic syndrome [INS], 38 with IgA or Henoch-Schoenlein nephropathy [IgAN/HSN]), we analyzed serum ADMA [nmol/ml], peripheral and central blood pressure, arterial stiffness (augmentation index – AIx75HR, pulse wave velocity – PWV), common carotid artery intima media thickness (cIMT), and selected clinical and biochemical parameters.

Results

In the study group, mean ADMA concentration was 1.66 ±1.19 [nmol/ml] and did not differ between INS and IgAN/HSN patients. We found no significant correlations between concentration of ADMA, cIMT [mm]/Z-score, PWV [m/s]/Z-score, and AIx75HR [%] in the whole group and in INS and IgAN/HSN patients. In the whole group of 80 children, ADMA correlated (p < 0.05) with BMI Z-score (r = –0.24), uric acid (r = –0.23), HDL-cholesterol (r = –0.25), and central mean arterial pressure (r = –0.25), in children with INS also with total protein (r = 0.37), albumin (r = 0.36), and total cholesterol (r = –0.40, p = 0.028). In multivariate analysis, serum albumin was the strongest determinant of ADMA in the whole group (β = 0.536, 95% CI: 0.013-1.060, p = 0.045).

Conclusions

1. In children with glomerulonephritis, measurement of asymmetric dimethylarginine cannot replace well established and validated methods of assessment of subclinical arterial damage. 2. In children with glomerular kidney diseases, ADMA concentration is related primarily to serum albumin concentration.

Effects of folic acid supplementation on serum homocysteine levels, lipid profiles, and vascular parameters in post-menopausal Korean women with type 2 diabetes mellitus

BACKGROUND/OBJECTIVES

Complications of diabetes, such as cardiovascular disease, are associated with increased mortality among type 2 diabetes mellitus patients. Homocysteine has been recently identified as a predictor of cardiovascular disease-related complications in diabetes. We investigated whether or not supplementation with folic acid tablets can lower homocysteine levels and improve parameters related with vascular complications.

SUBJECTS/METHODS

We conducted a non-randomized 8-week trial involving postmenopausal diabetic women (n = 25) supplemented with 800 µg of folic acid (400 µg twice a day) daily. Subjects' serum levels of folate, homocysteine, and vitamin B₁₂ were measured, along with vascular function and brachial-ankle pulse wave velocity.

RESULTS

Folic acid supplementation significantly increased serum folate levels (P < 0.0001), reduced homocysteine levels (P < 0.0001), and increased vitamin B₁₂ levels (P = 0.0063). There were significant decreases in low-density lipoprotein cholesterol levels as well as the ratios of low-density lipoprotein cholesterol to high-density lipoprotein cholesterol and total cholesterol to high-density lipoprotein cholesterol. Brachial-ankle pulse wave velocities were not altered by supplementation. Changes in serum vitamin B₁₂ after folic acid supplementation were negatively correlated with changes in brachial-ankle pulse wave velocity.

CONCLUSIONS

In this study on postmenopausal Korean women with type 2 diabetes mellitus, folic acid supplementation reduced serum homocysteine levels, increased serum folate and vitamin B₁₂ levels, and lowered lipid parameters.

Multidisciplinary Treatment of the Metabolic Syndrome Lowers Blood Pressure Variability Independent of Blood Pressure Control

Blood pressure (BP) variability (BPV) contributes to target organ damage independent of BP. The authors examined the effect of a 1-year multidisciplinary intervention on BPV in patients with the metabolic syndrome (MetS) as defined by criteria from the Third Report of the Adult Treatment Panel. Forty-four nondiabetic patients underwent clinical and biochemical profiling, 24-hour ambulatory BP monitoring (ABPM), body composition, carotid intima-media thickness, and carotid-femoral pulse wave velocity (PWV). The intervention targeted all MetS components. BPV was assessed by the standard deviation of daytime systolic BP derived from ABPM. Patients with low and high BPV (lower or higher than the median daytime standard deviation of 11.6 mm Hg) did not differ in regards to systolic and diastolic BP, age, fasting glucose, glycated hemoglobin, and body mass index, but the high-variability group had higher values of low-density lipoprotein and leg fat. The 1-year intervention resulted in weight reduction but not BP-lowering. BPV declined in the high-variability group in association with lowering of PWV, C-reactive protein, glycated hemoglobin, alanine aminotransferase, asymmetric dimethylarginine, and increased high-density lipoprotein cholesterol. A multidisciplinary intervention independent of BP-lowering normalized BPV, lowered PWV, and enhanced metabolic control.

Asymmetric dimethylarginine and long-term adverse cardiovascular events in patients with type 2 diabetes: relation with the glycemic control

Background and aims

Elevated plasma asymmetric dimethylarginine (ADMA) levels have been observed in patients with insulin resistance and diabetes, and have been reported to predict adverse cardiovascular events in type 2 diabetic patients. However, the relationship between ADMA and glycemic control in patients with type 2 diabetes remained controversial.

Methods and results

We evaluated 270 patients with type 2 diabetes and measured their plasma ADMA and hemoglobin A1c (HbA1c) levels by high performance liquid chromatography. The mean age was 67 ± 12 years. The mean plasma ADMA and HbA1c level were 0.46 ± 0.09 μmol/l and 7.8 ± 1.6%, respectively. There was no significant correlation between plasma ADMA level and HbA1c level (r = −0.09, p = 0.13). During the median follow-up period of 5.7 years (inter-quartile range: 5.0 − 7.3 years), major adverse cardiovascular event (MACE, including cardiovascular death, myocardial infarction and stroke) was observed in 55 patients (20.4%). Multivariate Cox regression analysis revealed that the ADMA tertile was an independent risk factor for MACE (ADMA tertile III versus ADMA tertile I: p = 0.026, HR: 2.31, 95% CI: 1.10 − 4.81). The prognosis predictive power of ADMA disappeared in patients with well glycemic control (HbA1c ≤6.5%), and the ADMA-HbA1c interaction p value was 0.01.

Conclusions

In patients with type 2 diabetes, ADMA might be an independent risk factor for long-term adverse cardiovascular events. However, ADMA was not correlated with serum HbA1c level, and in diabetic patients with HbA1c ≤6.5%, elevated ADMA level was no longer associated with increased risk of long-term prognosis. Our findings suggested that the prognosis predictive value of ADMA in type 2 diabetes might be modified by the glycemic control.

Normal weight diabetic patients versus obese diabetics: relation of overall and abdominal adiposity to vascular health

Objective

The present study investigated the impact of overall obesity defined by BMI and abdominal obesity defined by WC on vascular atherosclerotic changes in obese and normal weight diabetic subjects.

Design and methods

285 subjects were divided according to presence diabetes mellitus (DM) and obesity: Group 1 included 144 nonobese subjects without DM; Group 2 consisted of 141 type 2 diabetic patients. Then diabetic patients were divided into two groups according to presence of overall obesity, defined by BMI and furthermore, abdominal obesity, defined by waist circumference (WC). Pulse wave velocity (PWV) and augmentation index (AI) were performed using SphygmoCor (version 7.1, AtCor Medical, Sydney, Australia).

Results

Between Group Comparisons by BMI: Diabetic subjects with and without overall obesity did not differ from one another in terms of AI and PWV.

Between Group Comparisons by WC: AI as well as PWV increased consistently from Group 1 to Group 3, AI and PWV were significantly higher in abdominally obese diabetic subjects than in the diabetics without abdominal obesity (p = 0.008 and p = 0.013, respectively). Significant by-group differences in PWV and AI persisted after adjustment for age, sex, blood pressure, fasting glucose and BMI.

Conclusions

Abdominal obesity defined by WC was associated with significantly higher AI and PWV in in both diabetic men and women; whereas overall obesity defined by BMI did not predict adverse vascular changes in this study population. Abdominal obesity was associated with an adverse effect on blood vessels, independently of age, sex, blood pressure, fasting glucose and BMI.

Neck circumference and early stage atherosclerosis: the cardiometabolic risk in Chinese (CRC) study

Background

Neck circumference (NC) has been previously related to cardiometabolic risk factors. In this study we examined the association between NC and early stage atherosclerosis in Chinese adults.

Methods

The study samples were from a community-based health examination survey in central China. In total 2,318 men and women (18-64 y) were included in the final analyses. Carotid radial pulse wave velocity (crPWV), carotid femoral PWV (cfPWV), carotid artery dorsalis pedis PWV (cdPWV) and NC were measured.

Results

After adjustment for age, sex, lipids, glucose, blood pressure, heart rate, body mass index (BMI), high NC was significantly associated with an increasing trend of cfPWV, cdPWV and crPWV (P = 0.001, 0.049, and 0.038; respectively). In addition, we found significant interaction between hypertension status and NC level in relation to cfPWV, adjusted for age, sex, BMI, fasting glucose, lipids and heart rate(P for interaction = 0.034). The associations between NC and cfPWV were significant (P = 0.02) among those with hypertension, but not significant among those without hypertension.

Conclusions

Our data showed that high NC was associated with an increased risk of early stage atherosclerosis in Chinese adults, independent of other metabolic risk factors. Hypertension might modify the association between NC and cfPWV.

Restoration of asymmetric dimethylarginine-nitric oxide balance to prevent the development of hypertension

Despite the use of extensive antihypertensive therapy in patients with hypertension, little attention has been paid to early identification and intervention of individuals at risk for developing hypertension. The imbalance between nitric oxide (NO) and reactive oxygen species (ROS) resulting in oxidative stress has been implicated in the pathophysiology of hypertension. NO deficiency can precede the development of hypertension. Asymmetric dimethylarginine (ADMA) can inhibit nitric oxide synthase (NOS) and regulate local NO/ROS balance. Emerging evidence supports the hypothesis that ADMA-induced NO–ROS imbalance is involved in the development and progression of hypertension. Thus, this review summarizes recent experimental approaches to restore ADMA–NO balance in order to prevent the development of hypertension. Since hypertension might originate in early life, we also discuss the putative role of the ADMA–NO pathway in programmed hypertension. Better understanding of manipulations of the ADMA–NO pathway prior to hypertension in favor of NO will pave the way for the development of more effective medicine for the treatment prehypertension and programmed hypertension. However, more studies are needed to confirm the clinical benefit of these interventions.

Asymmetric dimethylarginine predicts decline of glucose tolerance in men with stable coronary artery disease: a 4.5-year follow-up study

Background

Endothelial dysfunction, largely dependent on impaired nitric oxide bioavailability, has been reportedly associated with incident type 2 diabetes. Our aim was to test the hypothesis that asymmetric dimethylarginine (ADMA), an endogenous inhibitor of nitric oxide formation, might be linked to future deterioration in glucose tolerance in stable coronary artery disease (CAD).

Methods

We studied 80 non-diabetic men (mean age 55 ± 11 years) with stable angina who underwent successful elective complex coronary angioplasty and were receiving a standard medication according to practice guidelines. Plasma ADMA and its structural isomer symmetric dimethylarginine (SDMA) were measured prior to coronary angiography. An estimate of insulin resistance by homeostasis model assessment (HOMA-IR index) was calculated from fasting insulin and glucose. Deterioration in glucose tolerance was defined as development of type 2 diabetes or progression from a normal glucose tolerance to impaired fasting glucose.

Results

Over a median follow-up of 55 months 11 subjects developed type 2 diabetes and 13 progressed to impaired fasting glucose. Incident deterioration of glucose tolerance was associated with ADMA (hazard ratio [HR] per 1-SD increment 1.64 [95% CI: 1.14–2.35]; P = 0.007), log (HOMA-IR index) (HR = 1.60 [1.16–2.20]; P = 0.004) and body-mass index (HR = 1.44 [0.95–2.17]; P = 0.08) by univariate Cox regression. ADMA (HR = 1.65 [1.14–2.38]; p = 0.008) and log (HOMA-IR index) (HR = 1.55 [1.10–2.17]; P = 0.01) were multivariate predictors of a decline in glucose tolerance. ADMA and SDMA were unrelated to body-mass index, HOMA-IR index, insulin or glucose.

Conclusions

ADMA predicts future deterioration of glucose tolerance independently of baseline insulin resistance in men with stable CAD. Whether this association reflects a contribution of endothelial dysfunction to accelerated decline of insulin sensitivity, or represents only an epiphenomenon accompanying pre-diabetes, remains to be elucidated. The observed relationship might contribute to the well-recognized ability of ADMA to predict cardiovascular outcome.

Differential associations of angiographic extent and severity of coronary artery disease with asymmetric dimethylarginine but not insulin resistance in non-diabetic men with stable angina: a cross-sectional study

Background

Asymmetric dimethylarginine (ADMA), an endogenous nitric oxide synthesis inhibitor, and insulin resistance (IR) have been implicated in atherogenesis. Our aim was to estimate relations between ADMA, the magnitude of IR and angiographic indices of extent and severity of coronary atherosclerosis in non-diabetic men with stable coronary artery disease (CAD).

Methods

We studied 151 non-diabetic men (mean age 57 ± 11 years) with stable angina, obstructive CAD (at least 1 luminal diameter stenosis of ≥70% in major coronary segments) and without heart failure, and 34 age-matched controls free of ≥50% coronary narrowings. The following CAD indices were computed: the number of major epicardial vessels with ≥70% stenosis, Sullivan extent score representing a proportion of the visible coronary tree with vessel wall irregularities, and Gensini score which reflects both CAD severity and extent, yet assigning a heavier weight to proximal segments and to the more severe narrowings by a non-linear point system. An estimate of IR was derived by homeostasis model assessment (HOMA-IR) from fasting insulin and glucose.

Results

Among the CAD patients, the proportions of subjects with 1-vessel, 2- vessel and 3-vessel CAD were 26%, 25% and 49%, respectively. ADMA levels were higher in patients with obstructive CAD compared to the controls (0.51 ± 0.10 vs. 0.46 ± 0.09 μmol/L [SD], P = 0.01), whereas HOMA-IR was similar (median, 3.2 [interquartile range: 2.4–4.9] vs. 2.9 [2.3–4.7], P = 0.2). Within the CAD group, ADMA increased across ascending quartiles of Sullivan score (Spearman’s rho = 0.23, P = 0.004), but not with Gensini score (rho = 0.12, P = 0.15) or the number of vessels involved (rho = 0.08, P = 0.3). ADMA correlated to log-transformed Sullivan score (Pearson's r = 0.21, P = 0.008), which was only slightly attenuated upon multivariate adjustment (β = 0.19 ± 0.08 [SEM], P = 0.015). HOMA-IR did not differ according to any measure of angiographic CAD (P ≥ 0.2). ADMA and log (HOMA-IR) were mutually unrelated (r = 0.07, P = 0.4).

Conclusions

ADMA is associated with diffuse but not focal coronary atherosclerosis in non-diabetic men with stable CAD irrespectively of the degree of IR. The independent relationship between ADMA and coronary atherosclerotic burden may contribute to the well-recognized prognostic effect of ADMA in CAD.