Asymmetric dimethylarginine and cardiovascular risk: systematic review and meta-analysis of 22 prospective studies

Asymmetric and symmetric dimethylarginine as markers of endothelial dysfunction in cerebrovascular disease: A prospective study

BACKGROUND AND AIM

Asymmetric dimethylarginine (ADMA) and symmetric dimethylarginine (SDMA) have been proposed as mediators of endothelial dysfunction. In this study, we aimed to investigate the diagnostic and prognostic role of ADMA and SDMA in acute cerebrovascular disease.

METHODS AND RESULTS

A prospective case-control study was performed, enrolling 48 patients affected by ischemic stroke with no cardioembolic origin, 20 patients affected by TIA, 40 subjects at high cardiovascular risk and 68 healthy subjects. ADMA levels were significantly lower in high-risk subjects (18.85 [11.78-22.83] μmol/L) than in patients with brain ischemic event, both transient (25.70 [13.15-40.20] μmol/L; p = 0.032) and permanent (24.50 [18.0-41.33] μmol/L; p = 0.001). SDMA levels were different not only between high-risk subjects and ischemic patients, but also between TIA and stroke patients, reaching higher levels in TIA group and lower levels in stroke group (1.15 [0.90-2.0] vs 0.68 [0.30-1.07] μmol/L; p < 0.001). SDMA was also correlated with short-term prognosis, with lower levels in case of adverse clinical course, evaluated by type of discharge (p = 0.009) and need of prolonged rehabilitation (p = 0.042).

CONCLUSIONS

The present study highlights the relationship between l-arginine, ADMA, SDMA and acute cerebrovascular events. Therefore, our results suggested a potential role of SDMA as a specific marker of transient ischemic damage and as a short-term positive prognostic marker.

Bariatric surgery modulates plasma levels of antibodies against angiotensin II type 1 and endothelin 1 type A receptor in severe obesity

PURPOSE

The contribution of endothelial-targeted autoantibodies against the angiotensin II type 1 receptor (anti-AT1R) and the anti-endothelin 1 type A receptor (anti-ETAR1) has been proposed in the development of cardiovascular diseases. However, no data have been reported yet in obesity. In this observational study we evaluated the relationship between anthropometric and metabolic parameters and anti-AT1R and anti-ETAR1 concentrations in a cohort of patients with severe obesity and associated comorbidities undergoing bariatric surgery.

METHODS

Clinical evaluation and metabolic assessment were performed in 36 subjects referring to our Center for the Study and Integrated Treatment of Obesity at the University Hospital of Padova. Circulating inflammatory adipocytokines and the endothelial dysfunction marker asymmetric dimethylarginine (ADMA) were evaluated; plasma levels of anti-AT1R and anti-ETAR1 were also determined. 10 normal-weight subjects were considered as a control group. 29 patients out of 36 were re-evaluated after surgery.

RESULTS

With respect to normal-weight controls patients showed significantly higher plasma levels of anti-AT1R (28 ± 20.4 vs 13.5 ± 2.8 U/mL, p < 0.005) and ADMA (0.8 ± 0.1 vs 0.54 ± 0.08 uM/L, p < 0.0001) but not anti-ETAR1 (14.2 ± 1.3 vs 13.3 ± 2 U/mL, p = 0.1). Anti-AT1R concentration showed an increasing trend with the worsening of glycemic status, while the presence of arterial hypertension among the patients did not affect autoantibodies levels. One year after surgery, a significant improvement in body weight and metabolic and inflammatory parameters was observed, along with a significant reduction of anti-AT1R (28.1 ± 20.4 U/mL vs 22.6 ± 16 U/mL, p < 0.05) and anti-ETAR1 (14.2 ± 1.3 U/L vs 13 ± 1.6 U/L, p < 0.01).

CONCLUSIONS

Subjects with obesity present higher plasma levels of anti-AT1R which are more related to glycemic profile than blood pressure levels, and are reduced by bariatric surgery. Considering the detrimental effects of these autoantibodies on vascular health, they should be assessed as potential biomarkers in obesity and metabolic diseases.

Associations of Plasma Metabolites With Risks of Incident Stroke and Its Subtypes in Chinese Adults

BACKGROUND

Metabolomics studies have identified various metabolic markers associated with stroke risk, yet much uncertainty persists regarding heterogeneity in these associations between different stroke subtypes. We aimed to examine metabolic profiles associated with incident stroke and its subtypes in Chinese adults.

METHODS AND RESULTS

We performed a nested case-control study within the Dongfeng-Tongji cohort, including 1029 and 266 incident cases of ischemic stroke (IS) and hemorrhagic stroke (HS), respectively, with a mean follow-up period of 6.1±2.3 years. Fifty-five metabolites in fasting plasma were measured by ultra-high-performance liquid chromatography-mass spectrometry. We examined the associations of metabolites with the risks of total stroke, IS, and HS, with a focus on the comparison of associations of plasma metabolite with IS and HS, using conditional logistic regression. We found that increased levels of asymmetrical/symmetrical dimethylarginine and glutamate were significantly associated with elevated risk of total stroke (odds ratios and 95%, 1.20 [1.08-1.34] and 1.22 [1.09-1.36], respectively; both Benjamini-Hochberg-adjusted P <0.05). When examining stroke subtypes, asymmetrical/symmetrical dimethylarginine was nominally associated with both IS and HS (odds ratios [95% CIs]: 1.16 [1.03-1.31] and 1.39 [1.07-1.81], respectively), while glutamate was associated with only IS (odds ratios [95% CI]: 1.26 [1.11-1.43]). The associations of glutamate with IS risk were significantly stronger among participants with hypertension and diabetes than among those without these diseases (both P for interaction <0.05).

CONCLUSIONS

This study validated the positive associations of asymmetrical/symmetrical dimethylarginine and glutamate with stroke risk, mainly that of IS, in a Chinese population, and revealed a novel unanimous association of with both IS and HS. Our findings provided potential intervention targets for stroke prevention.

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.

Atherothrombotic Risk Factors in Patients With Rheumatoid Arthritis

BACKGROUND

The onset of cardiovascular complications has increased the mortality rate in rheumatoid arthritis (RA) patients. Presently, there is a need to diagnose cardiovascular co-morbidity in rheumatic disease. While biomarkers such as P-selectin glycoprotein ligand-1 (PSGL-1), fibrinogen, anti-thrombin III (AT-III), hsCRP, lipoprotein (a) (lp(a)), leptin, adiponectin, and asymmetric dimethyl arginine (ADMA) are already established as independent risk factors for the development of atherosclerosis, the association of these biomarkers with disease activity in RA patients is unclear.

METHODS

The case-control study comprised 40 cases along with age- and gender-matched controls recruited from a tertiary care hospital in southern India. Platelet activation in plasma was analyzed by flow cytometry using CD41 per CPCY 5.5 (platelet marker) and human CD62P FITC monoclonal antibody (P-selectin marker). Other parameters were quantified through nephelometry and ELISA. The association between the risk factors and RA disease severity, as per the disease activity score (DAS/DAS28), was analyzed. Furthermore, an ROC analysis was done to assess the utility of these biomarkers in the diagnosis of RA.

RESULTS

With the exception of leptin, adiponectin, and ADMA, there was a significant increase in the levels of PSGL-1, fibrinogen, AT-III, hsCRP, and lp(a) when compared to healthy controls. Conventional risk factors contributing to dyslipidemia were also assessed, in which the low-density lipoprotein (LDL)/high-density lipoprotein (HDL) ratio was found to be significantly higher in RA patients compared to controls. Moreover, a significant positive correlation was identified between DAS score and activated platelets, fibrinogen, and hsCRP. ROC analysis identified that fibrinogen could predict the RA disease status with 95% accuracy, followed by activated platelets and hsCRP.

CONCLUSION

Several of the studied atherothrombotic risk factors were significantly altered in patients with RA. Activated platelets, fibrinogen, and hsCRP were associated with disease activity and also served as good diagnostic predictors for RA. Based on our findings, further studies could explore the potential of introducing anti-thrombotic agents in the treatment regimen of patients with RA.

Pathophysiology and clinical relevance of atrial myopathy

Atrial myopathy is a condition that consists of electrical, structural, contractile, and autonomic remodeling of the atria and is the substrate for development of atrial fibrillation, the most common arrhythmia. Pathophysiologic mechanisms driving atrial myopathy are inflammation, oxidative stress, atrial stretch, and neurohormonal signals, e.g., angiotensin-II and aldosterone. These mechanisms initiate the structural and functional remodeling of the atrial myocardium. Novel therapeutic strategies are being developed that target the pathophysiologic mechanisms of atrial myopathy. In this review, we will discuss the pathophysiology of atrial myopathy, as well as diagnostic and therapeutic strategies.

Lipidomics for diagnosis and prognosis of pulmonary hypertension

Background

Pulmonary hypertension (PH) poses a significant health threat with high morbidity and mortality, necessitating improved diagnostic tools for enhanced management. Current biomarkers for PH lack functionality and comprehensive diagnostic and prognostic capabilities. Therefore, there is a critical need to develop biomarkers that address these gaps in PH diagnostics and prognosis.

Methods

To address this need, we employed a comprehensive metabolomics analysis in 233 blood based samples coupled with machine learning analysis. For functional insights, human pulmonary arteries (PA) of idiopathic pulmonary arterial hypertension (PAH) lungs were investigated and the effect of extrinsic FFAs on human PA endothelial and smooth muscle cells was tested in vitro.

Results

PA of idiopathic PAH lungs showed lipid accumulation and altered expression of lipid homeostasis-related genes. In PA smooth muscle cells, extrinsic FFAs caused excessive proliferation and endothelial barrier dysfunction in PA endothelial cells, both hallmarks of PAH.In the training cohort of 74 PH patients, 30 disease controls without PH, and 65 healthy controls, diagnostic and prognostic markers were identified and subsequently validated in an independent cohort. Exploratory analysis showed a highly impacted metabolome in PH patients and machine learning confirmed a high diagnostic potential. Fully explainable specific free fatty acid (FFA)/lipid-ratios were derived, providing exceptional diagnostic accuracy with an area under the curve (AUC) of 0.89 in the training and 0.90 in the validation cohort, outperforming machine learning results. These ratios were also prognostic and complemented established clinical prognostic PAH scores (FPHR4p and COMPERA2.0), significantly increasing their hazard ratios (HR) from 2.5 and 3.4 to 4.2 and 6.1, respectively.

Conclusion

In conclusion, our research confirms the significance of lipidomic alterations in PH, introducing innovative diagnostic and prognostic biomarkers. These findings may have the potential to reshape PH management strategies.

Association between asymmetric dimethylarginine and sarcopenia in community-dwelling older women

Asymmetric dimethylarginine (ADMA) is an endogenous inhibitor of endothelium nitric oxide synthesis and causes endothelial dysfunction that may be related to sarcopenia. However, the association between ADMA and sarcopenia has not been studied. We evaluated the correlations between plasma ADMA levels and sarcopenia in community-dwelling older women. In total, 144 community-dwelling older women participated in this study. Plasma ADMA levels were measured using a competitive enzyme-linked immunosorbent assay. Skeletal muscle mass, measured in terms of bioimpedance and grip strength, was used to assess sarcopenia. Plasma ADMA levels were significantly higher in participants with sarcopenia than in those without sarcopenia. Through receiver-operating characteristic curve analysis, the cutoff value of plasma ADMA level for sarcopenia was estimated at 0.57 μM. Sarcopenia was significantly more prevalent in participants with higher plasma ADMA levels than in those with lower plasma ADMA levels. According to logistic regression analysis, the crude odds ratio of higher plasma ADMA levels in participants with sarcopenia was 4.57 (95% confidence interval, 1.82-11.47; p = 0.001). Reductions in the skeletal muscle mass index over 2 years were significantly greater in participants with higher plasma ADMA levels. In conclusion, plasma ADMA levels were significantly associated with sarcopenia in community-dwelling older women.

Effects of l-Arginine Plus Vitamin C Supplementation on l-Arginine Metabolism in Adults with Long COVID: Secondary Analysis of a Randomized Clinical Trial

Altered l-arginine metabolism has been described in patients with COVID-19 and has been associated with immune and vascular dysfunction. In the present investigation, we determined the serum concentrations of l-arginine, citrulline, ornithine, monomethyl-l-arginine (MMA), and symmetric and asymmetric dimethylarginine (SDMA, ADMA) in adults with long COVID at baseline and after 28-days of l-arginine plus vitamin C or placebo supplementation enrolled in a randomized clinical trial, compared with a group of adults without previous history of SARS-CoV-2-infection. l-arginine-derived markers of nitric oxide (NO) bioavailability (i.e., l-arginine/ADMA, l-arginine/citrulline+ornithine, and l-arginine/ornithine) were also assayed. Partial least squares discriminant analysis (PLS–DA) models were built to characterize systemic l-arginine metabolism and assess the effects of the supplementation. PLS–DA allowed discrimination of participants with long COVID from healthy controls with 80.2 ± 3.0% accuracy. Lower markers of NO bioavailability were found in participants with long COVID. After 28 days of l-arginine plus vitamin C supplementation, serum l-arginine concentrations and l-arginine/ADMA increased significantly compared with placebo. This supplement may therefore be proposed as a remedy to increase NO bioavailability in people with long COVID.

The Relationship of Left Ventricular Diastolic Dysfunction and Asymmetrical Dimethylarginine as a Biomarker of Endothelial Dysfunction with Cardiovascular Risk Assessed by Systematic Coronary Risk Evaluation2 Algorithm and Heart Failure-A Cross-Sectional Study

Background: Cardiovascular (CV) risk factors, causing endothelial dysfunction (ED) and left ventricular diastolic dysfunction (LVDD), contribute to an increased risk of heart failure (HF). The aim of this study was to determine the relationship between the occurrence of LVDD and ED with CV risk assessed by the Systematic Coronary Risk Evaluation2 (SCORE2) algorithm and HF. Methods: In the period from November 2019 to May 2022, a cross-sectional study that included 178 middle-aged adults was conducted. Transthoracic echocardiography (TTE) was used to assess left ventricular (LV) diastolic and systolic function. ED was assessed using the plasma values of asymmetric dimethylarginine (ADMA) and was determined using the ELISA method. Results: The majority of subjects with LVDD grades 2 and 3 had high/very high SCORE2, developed HF and all were taking medication (p < 0.001). They also had significantly lowest plasma ADMA values (p < 0.001). We found that the reduction of ADMA concentration is influenced by certain groups of drugs, or more significantly, by their combinations (p < 0.001). Conclusions: In our study, we confirmed a positive correlation between LVDD, HF and SCORE2 severity. The results showed a negative correlation between the biomarkers of ED, LVDD severity, HF, and SCORE2, which we believe is due to medication effects.

Comparison between one and two-dimensional liquid chromatographic approaches for the determination of plasmatic stroke biomarkers by isotope dilution and tandem mass spectrometry

This work presents the evaluation of one- and two-dimensional liquid chromatography for the quantification of three stroke outcome predictors in plasma. Isotopically labelled analogues of L-arginine (L-Arg), asymmetric dimethylarginine (ADMA) and symmetric dimethylarginine (SDMA) are used to quantify the three analytes by isotope dilution and tandem mass spectrometry. Chromatographic isotope effects were not observed between natural L-Arg and its ¹⁵N-labelled analogue but they were observed between natural ADMA and SDMA and their multiple deuterated analogues. Under these conditions, bidimensional chromatography through the use of an automated multiple heart cutting mode provided unsatisfactory results for ADMA and SDMA due to the different amounts of natural and labelled compounds transferred from the first to the second chromatographic dimension. In contrast, using one dimensional liquid chromatography after a derivatization step to esterify carboxylic groups, chromatographic isotope effects did not alter the initial mass balance as full coelution of natural and labelled analogues or baseline resolution between the analytes was not required. This method was successfully validated following the Clinical & Laboratory Standards Institute guidelines and applied to the analysis of plasma samples from patients who had suffered from an intraparenchymal haemorrhagic stroke.

Cardiovascular Risk Assessment in Rheumatoid Arthritis: Accelerated Atherosclerosis, New Biomarkers, and the Effects of Biological Therapy

Rheumatoid arthritis (RA), one of the most common of the chronic inflammatory autoimmune diseases (CIADs), is recognized as an independent cardiovascular risk factor. Traditional risk factors such as smoking, arterial hypertension, dyslipidemia, insulin resistance, and obesity are frequently found in RA. Given the increased risk of mortality and morbidity associated with cardiovascular disease (CVD) in RA patients, screening for risk factors is important. Moreover, there is a need to identify potential predictors of subclinical atherosclerosis. Recent studies have shown that markers such as serum homocysteine, asymmetric dimethylarginine, or carotid intima-media thickness (cIMT) are correlated with cardiovascular risk. Although RA presents a cardiovascular risk comparable to that of diabetes, it is not managed as well in terms of acute cardiovascular events. The introduction of biological therapy has opened new perspectives in the understanding of this pathology, confirming the involvement and importance of the inflammatory markers, cytokines, and the immune system. In addition to effects in inducing remission and slowing disease progression, most biologics have demonstrated efficacy in reducing the risk of major cardiovascular events. Some studies have also been conducted in patients without RA, with similar results. However, early detection of atherosclerosis and the use of targeted therapies are the cornerstone for reducing cardiovascular risk in RA patients.

Asymmetric dimethylarginine and gestational diabetes mellitus: a systematic review and meta-analysis

PURPOSE

Emerging evidence demonstrates that asymmetric dimethylarginine (ADMA) levels are elevated in patients with or at risk of cardiovascular disease (CVD). Since women with gestational diabetes mellitus (GDM) are at high risk of future CVD, we conducted a systematic review and meta-analysis to compare ADMA concentrations between women with and without GDM during pregnancy and postpartum.

METHODS

PubMed, Google Scholar, EMBASE, and CINAHL databases were searched. The review protocol is registered in PROSPERO (CRD42021276796). Study selection, data extraction, and data analyses were performed in accordance with PRISMA guidelines. Random-effects model was used to quantify ADMA levels in the study groups.

RESULTS

Eleven studies provided data on 1148 women. Mean plasma ADMA concentration was 0.04 μmol/L (95% confidence interval (CI) -0.06-0.15) higher in pregnant women with GDM than those without GDM, but no significant difference was observed. In contrast, our meta-analysis demonstrated a significant increase in postpartum mean ADMA concentration (Mean Difference (MD) 0.11 μmol/L; 95% CI 0.05-0.16) among women with previous GDM compared to women without previous GDM.

CONCLUSION

Elevated ADMA levels in GDM may be a CVD risk factor, suggesting that ADMA may be a potential biomarker for early CVD risk prediction in women with GDM.

Rare and common genetic determinants of metabolic individuality and their effects on human health

Garrod's concept of 'chemical individuality' has contributed to comprehension of the molecular origins of human diseases. Untargeted high-throughput metabolomic technologies provide an in-depth snapshot of human metabolism at scale. We studied the genetic architecture of the human plasma metabolome using 913 metabolites assayed in 19,994 individuals and identified 2,599 variant-metabolite associations (P < 1.25 × 10^-11) within 330 genomic regions, with rare variants (minor allele frequency ≤ 1%) explaining 9.4% of associations. Jointly modeling metabolites in each region, we identified 423 regional, co-regulated, variant-metabolite clusters called genetically influenced metabotypes. We assigned causal genes for 62.4% of these genetically influenced metabotypes, providing new insights into fundamental metabolite physiology and clinical relevance, including metabolite-guided discovery of potential adverse drug effects (DPYD and SRD5A2). We show strong enrichment of inborn errors of metabolism-causing genes, with examples of metabolite associations and clinical phenotypes of non-pathogenic variant carriers matching characteristics of the inborn errors of metabolism. Systematic, phenotypic follow-up of metabolite-specific genetic scores revealed multiple potential etiological relationships.

Effect of metformin on arginine and dimethylarginines in patients with advanced type 2 diabetes: A post hoc analysis of a randomized trial

AIM

To study the effect of metformin on plasma levels of arginine, asymmetric dimethylarginine (ADMA) and symmetric dimethylarginine (SDMA), indicators of the nitric oxide pathway.

MATERIALS AND METHODS

In this post hoc analysis of the HOME trial, we analysed plasma levels of arginine, ADMA and SDMA during the 4.3-year follow-up (comparing the effects of metformin versus placebo on top of insulin therapy). Statistical analysis was performed with a mixed model approach, in which simultaneously constant treatment effects were estimated, as well as time-dependent treatment effects.

RESULTS

We found that metformin compared with placebo did not affect ADMA or SDMA plasma levels but rapidly decreased arginine plasma levels and hence the arginine to ADMA ratio. The constant treatment effect on ADMA was 0.99 (95% CI 0.97, 1.00) relative to placebo and the time-dependent treatment effect was 1.00 (95% CI 1.00, 1.01). By contrast, the constant treatment effect on arginine was 0.86 (95% CI 0.84, 0.88), with only a minimal time-dependent change of 1.01 (95% CI 1.00, 1.01).

CONCLUSIONS

The potential benefits of metformin on endothelial function cannot be explained by a decrease in ADMA or by improved global arginine availability. The clinical significance of the decreased arginine plasma levels is not clear and can be harmful or beneficial, depending on the mechanism involved. However, a potential effect of metformin on the nitric oxide pathway is not restricted to the studied metabolites.

Overexpression of alanine-glyoxylate aminotransferase 2 protects from asymmetric dimethylarginine-induced endothelial dysfunction and aortic remodeling

Elevated plasma concentrations of asymmetric dimethylarginine (ADMA) are associated with an increased risk of mortality and adverse cardiovascular outcomes. ADMA can be metabolized by dimethylarginine dimethylaminohydrolases (DDAHs) and by alanine-glyoxylate aminotransferase 2 (AGXT2). Deletion of DDAH1 in mice leads to elevation of ADMA in plasma and increase in blood pressure, while overexpression of human DDAH1 is associated with a lower plasma ADMA concentration and protective cardiovascular effects. The possible role of alternative metabolism of ADMA by AGXT2 remains to be elucidated. The goal of the current study was to test the hypothesis that transgenic overexpression of AGXT2 leads to lowering of plasma levels of ADMA and protection from vascular damage in the setting of DDAH1 deficiency. We generated transgenic mice (TG) with ubiquitous overexpression of AGXT2. qPCR and Western Blot confirmed the expression of the transgene. Systemic ADMA levels were decreased by 15% in TG mice. In comparison with wild type animals plasma levels of asymmetric dimethylguanidino valeric acid (ADGV), the AGXT2 associated metabolite of ADMA, were six times higher. We crossed AGXT2 TG mice with DDAH1 knockout mice and observed that upregulation of AGXT2 lowers plasma ADMA and pulse pressure and protects the mice from endothelial dysfunction and adverse aortic remodeling. Upregulation of AGXT2 led to lowering of ADMA levels and protection from ADMA-induced vascular damage in the setting of DDAH1 deficiency. This is especially important, because all the efforts to develop pharmacological ADMA-lowering interventions by means of upregulation of DDAHs have been unsuccessful.

Arginine catabolism metabolites and atrial fibrillation or heart failure risk: 2 case-control studies within the Prevención con Dieta Mediterránea (PREDIMED) trial

BACKGROUND

Arginine-derived metabolites are involved in oxidative and inflammatory processes related to endothelial functions and cardiovascular risks.

OBJECTIVES

We prospectively examined the associations of arginine catabolism metabolites with the risks of atrial fibrillation (AF) or heart failure (HF), and evaluated the potential modifications of these associations through Mediterranean diet (MedDiet) interventions in a large, primary-prevention trial.

METHODS

Two nested, matched, case-control studies were designed within the Prevención con Dieta Mediterránea (PREDIMED) trial. We selected 509 incident cases and 547 matched controls for the AF case-control study and 326 cases and 402 matched controls for the HF case-control study using incidence density sampling. Fasting blood samples were collected at baseline and arginine catabolism metabolites were measured using LC-tandem MS. Multivariable conditional logistic regression models were applied to test the associations between the metabolites and incident AF or HF. Interactions between metabolites and intervention groups (MedDiet groups compared with control group) were analyzed with the likelihood ratio test.

RESULTS

Inverse association with incident AF was observed for arginine (OR per 1 SD, 0.83; 95% CI: 0.73-0.94), whereas a positive association was found for N1-acetylspermidine (OR for Q4 compared with Q1 1.58; 95% CI: 1.13-2.25). For HF, inverse associations were found for arginine (OR per 1 SD, 0.82; 95% CI: 0.69-0.97) and homoarginine (OR per 1 SD, 0.81; 95% CI: 0.68-0.96), and positive associations were found for the asymmetric dimethylarginine (ADMA) and symmetric dimethlyarginine (SDMA) ratio (OR per 1 SD, 1.19; 95% CI: 1.02-1.41), N1-acetylspermidine (OR per 1 SD, 1.34; 95% CI: 1.12-1.60), and diacetylspermine (OR per 1 SD, 1.20; 95% CI: 1.02-1.41). In the stratified analysis according to the dietary intervention, the lower HF risk associated with arginine was restricted to participants in the MedDiet groups (P-interaction = 0.044).

CONCLUSIONS

Our results suggest that arginine catabolism metabolites could be involved in AF and HF. Interventions with the MedDiet may contribute to strengthen the inverse association between arginine and the risk of HF. This trial was registered at controlled-trials.com as ISRCTN35739639.

Effects of adult growth hormone deficiency and replacement therapy on the cardiometabolic risk profile

Adult growth hormone deficiency (AGHD) is considered a rare endocrine disorder involving patients with childhood-onset and adult-onset growth hormone deficiency (AoGHD) and characterized by adverse cardiometabolic risk profile. Besides traditional cardiovascular risk factors, endothelial dysfunction, low-grade inflammation, impaired adipokine profile, oxidative stress and hypovitaminosis D may also contribute to the development of premature atherosclerosis and higher cardiovascular risk in patients with AGHD. Growth hormone replacement has been proved to exert beneficial effects on several cardiovascular risk factors, but it is also apparent that hormone substitution in itself does not eliminate all cardiometabolic abnormalities associated with the disease. Novel biomarkers and diagnostic techniques discussed in this review may help to evaluate individual cardiovascular risk and identify patients with adverse cardiometabolic risk profile. In the absence of disease-specific guidelines detailing how to assess the cardiovascular status of these patients, we generally recommend close follow-up of the cardiovascular status as well as low threshold for a more detailed evaluation.

Hypertension: Potential Player in Cardiovascular Disease Incidence in Preeclampsia

Preeclampsia (PE) is one of the complications, that threatens pregnant mothers during pregnancy. According to studies, it accounts for 3-7% of all pregnancies, and also is effective in preterm delivery. PE is the third leading cause of death in pregnant women. High blood pressure in PE can increase the risk of developing cardiovascular disease (CVD) in cited individuals, and is one of the leading causes of death in PE individuals. Atrial natriuretic peptide (ANP), Renin-Angiotensin system and nitric oxide (NO) are some of involved factors in regulating blood pressure. Therefore, by identifying the signaling pathways, that are used by these molecules to regulate and modulate blood pressure, appropriate treatment strategies can be provided to reduce blood pressure through target therapy in PE individuals; consequently, it can reduce CVD risk and mortality.

Effects of Physical Prehabilitation on the Dynamics of the Markers of Endothelial Function in Patients Undergoing Elective Coronary Bypass Surgery

Our aim in this study was to evaluate the effect of physical training performed before CABG on the perioperative dynamics of the serum levels of asymmetric dimethylarginine (ADMA) and endothelin-1 (ET-1) of patients with stable coronary heart disease (CHD). Patients in the preoperative period were randomized into two groups: the training group (n = 43) underwent high-intensity treadmill training; the patients in the control group (n = 35) received no training before the procedure. The serum concentrations of ADMA and ET-1 were determined in the perioperative period, and the course of the early postoperative period was analyzed. In the training group, we found a significantly lower incidence of postoperative complications during hospital stays (p = 0.013). At the end of the training program, the ADMA levels were 1.8 times higher in the controls than in the training group (p = 0.001). We found that type 2 diabetes increased the probability of complications by 12 times (OR: 12.3; 95% CI: 1.24–121.5; p = 0.03), as well as elevating the concentration of ET-1 on the eve of surgery (OR: 10.7; 95% CI: 1.4–81.3; p = 0.02). Physical prehabilitation reduced the likelihood of complications nine times (OR: 0.11; 95% CI: 0.02–0.83; p = 0.03). The AUC was 0.851 ± 0.07 (95% CI: 0.71–0.98). The obtained results indicate the benefit of physical training during the prehabilitation stage since it can help to preserve endothelial function.

An updated systematic review and meta-analysis of the effect of statins on asymmetric dimethylarginine

OBJECTIVES

We conducted an updated systematic review and meta-analysis of the effect of statins on serum or plasma concentrations of the endogenous inhibitor of endothelial nitric oxide synthase, asymmetric N^G,N^G-dimethyl-l-arginine (ADMA).

METHODS

A systematic literature search was conducted in the electronic databases PubMed, Web of Science, and Scopus, from inception to July 2021. Risk of bias and certainty of evidence were assessed using the Joanna Briggs Institute Critical Appraisal Checklist for analytical studies and GRADE, respectively.

RESULTS

In 23 studies, reporting 25 treatment arms in 845 participants (mean age 53 years, 57% males, treatment duration 4-48 weeks), statins significantly reduced ADMA concentrations (SMD = -0.39, 95% CI -0.62 to -0.16, p = 0.001; moderate certainty of evidence). The extreme heterogeneity observed was substantially reduced in study subgroups of specific class and individual statins, regional areas, and analytical methods for ADMA concentrations. There was no publication bias. In sensitivity analysis, the corresponding SMD values were not substantially modified when individual studies were sequentially removed. Significant associations were observed, in meta-regression, between the SMD and publication year (t = -3.25, p = 0.003), but not baseline cholesterol concentrations.

CONCLUSION

Statin treatment significantly lowers ADMA concentrations. This effect is independent of baseline cholesterol. Prospective studies are required to determine whether ADMA-lowering mediates, at least partly, the protective effects of statins against atherosclerotic cardiovascular disease. (PROSPERO registration number: CRD42021275123).

8-Isoprostanes and Asymmetric Dimethylarginine as Predictors of Mortality in Patients Following Coronary Bypass Surgery: A Long-Term Follow-Up Study

Background: We previously demonstrated that enhanced oxidative stress and reduced nitric oxide bioavailability are associated with unfavorable outcomes early after coronary artery bypass grafting. It is not known whether these processes may impact long-term results. We sought to assess whether during long-term follow-up, markers of oxidative stress and nitric oxide bioavailability may predict cardiovascular mortality following bypass surgery. Methods: We studied 152 consecutive patients (118 men, age 65.2 ± 8.3 years) who underwent elective, primary, isolated on-pump bypass surgery. We measured plasma 8-iso-prostaglandin F2α and asymmetric dimethylarginine before surgery and twice after surgery (18–36 h and 5–7 days). We assessed all-cause and cardiovascular death in relation to these two biomarkers during a mean follow-up time of 11.7 years. Results: The overall mortality was 44.7% (4.7 per 100 patient-years) and cardiovascular mortality was 21.0% (2.2 per 100 patient-years). Baseline 8-iso-prostaglandin F2α was associated with cardiovascular mortality (HR 1 pg/mL 1.010, 95% CI 1.001–1.021, p = 0.036) with the optimal cut-off ≤ 364 pg/mL for higher survival rate (HR 0.460, 95% CI 0.224–0.942, p = 0.030). Asymmetric dimethylarginine > 1.01 μmol/L measured 18–36 h after surgery also predicted cardiovascular death (HR 2.467, 95% CI 1.140–5.340, p = 0.020). Additionally, elevated 8-iso-prostaglandin F2α measured at the same time point associated with all-cause mortality (HR 1 pg/mL 1.007, 95% CI 1.000–1.014, p = 0.048). Conclusions: Our findings indicate that in advanced coronary disease, increased oxidative stress, reflected by 8-iso-prostaglandin F2α before bypass surgery and enhanced asymmetric dimethylarginine accumulation just after the surgery are associated with cardiovascular death during long-term follow-up

The Functional Polymorphism of DDAH2 rs9267551 Is an Independent Determinant of Arterial Stiffness

Background: The association of circulating asymmetric dimethylarginine (ADMA) levels with cardiovascular risk and arterial stiffness has been reportedly demonstrated, although the causal involvement of ADMA in the pathogenesis of these conditions is still debated. Dimethylaminohydrolase 2 (DDAH2) is the enzyme responsible for ADMA hydrolysis in the vasculature, and carriers of the polymorphism rs9267551 C in the 5′-UTR of DDAH2 have been reported to have higher DDAH2 expression and reduced levels of serum ADMA.

Approach and Results: We genotyped rs9267551 in 633 adults of European ancestry and measured their carotid–femoral pulse wave velocity (cfPWV), the gold-standard method to estimate arterial stiffness. cfPWV resulted significantly lower in rs9267551 C allele carriers (Δ = −1.12 m/s, P < 0.01) after correction for age, sex and BMI, and a univariate regression showed that the presence of rs9267551 C variant was negatively associated with cfPWV (β = −0.110, P < 0.01). In a multivariable regression model, subjects carrying the rs9267551 C allele manifested significantly lower cfPWV than GG carriers (β = −0.098, P = 0.01) independently from several potential confounders. We measured circulating ADMA levels in a subset of 344 subjects. A mediation analysis revealed that the effect of DDAH2 rs9267551 genotype on cfPWV was mediated by the variation in ADMA levels.

Conclusions: These evidences hint that the presence of rs9267551 C allele may explain, at least in part, a reduction in vessel rigidity as measured by cfPWV, and support the attribution of a causative role to ADMA in the pathogenesis of arterial stiffness.

Short-Term Effects of Supplemental L-Arginine, Diosmin, Troxerutin, and Hesperidin in Diabetic Patients: A Pilot Study

Background and Aims

Inflammatory, oxidative stress, and endothelial dysfunction play a key role in the pathogenesis of long-term cardiovascular complications in patients with diabetes. The present observational prospective study is aimed at evaluating the effects of micronutrients and phytochemicals contained in the dietary supplement Flebotrofine® (AMNOL Chimica Biologica) on biochemical markers of inflammation, endothelial dysfunction, and glycemic control in patients with diabetes.

Methods

105 type 1 or type 2 diabetes patients regularly took a daily dose of the dietary supplement Flebotrofine® for three consecutive months, and haematological and biochemical parameters were checked at baseline, after three months of treatment, and one month after its suspension. Statistical comparison of the laboratory parameters was performed using the two-tailed ANOVA test for repeated samples with a statistical significance level set at p < 0.05.

Results

The daily use of Flebotrofine® did not change the glycemic metabolic compensation of enrolled patients. After three months of regular Flebotrofine® intake, the plasma levels of the antioxidant β-carotene and of arginine were significantly higher compared with the baseline values, with a decrease in the ADMA/arginine ratio. In contrast, apolipoprotein B, ApoB/ApoA1 ratio, and platelet and leukocyte counts significantly dropped.

Conclusion

The daily use of Flebotrofine® might be a valid supplement of arginine, the precursor of NO, and essential in the prevention of endothelial dysfunction. The regular intake of arginine and phytochemicals also improved the antioxidant and antithrombotic profile of enrolled patients. Therefore, Flebotrofine® could be a useful dietary supplement to prevent long-term complications in patients with diabetes.

Effect of profilin-1 on the asymmetric dimethylarginine-induced vascular lesion-associated hypertension

Previous studies have demonstrated that the levels of asymmetric dimethylarginine (ADMA), an endogenous inhibitor of nitric oxide (NO) synthesis, are strongly associated with hypertension, diabetes, and cardiovascular diseases. Profilin-1, an actin-binding protein, has been documented to be involved in endothelial injury and in the proliferation of vascular smooth muscle cells resulting from hypertension. However, the role of profilin-1 in ADMA-induced vascular injury in hypertension remains largely unknown. Forty healthy subjects and forty-two matched patients with essential hypertension were enrolled, and the related indexes of vascular injury in plasma were detected. Rat aortic smooth muscle cells (RASMCs) were treated with different concentrations of ADMA for different periods of time and transfected with profilin-1 small hairpin RNA to interrupt the expression of profilin-1. To determine the role of the Janus kinase 2/signal transducer and activator of transcription 3 (JAK2/STAT3) pathway, RASMCs were pretreated with AG490 or rapamycin. The expression of profilin-1 was tested using real-time polymerase chain reaction (PCR) and western blot analysis. Cell proliferation was measured by flow cytometry and 3-(4,5-dimethylthiazol-2yl)-2,5-diphenyltetrazoliumbromide assays. Compared with healthy subjects, the levels of ADMA and profilin-1 were markedly elevated in hypertensive individuals, while the levels of NO were significantly decreased (p < 0.05). In vitro, studies showed ADMA-induced profilin-1 expression in a concentration- and time-dependent manner in RASMCs (p < 0.05), concomitantly with promoting the proliferation of RASMCs. Furthermore, ADMA-mediated proliferation of RASMCs and upregulation expression of profilin-1 were inhibited by blockade of the JAK2/STAT3 pathway or knockdown of profilin-1. Profilin-1 implicated in the ADMA-mediated vascular lesions in hypertension.

Associations of circulating dimethylarginines with the metabolic syndrome in the Framingham Offspring study

Background

Circulating levels of the endogenous inhibitor of nitric oxide synthase, asymmetric dimethylarginine (ADMA), are positively associated with the prevalence of metabolic syndrome (MetS) in cross-sectional investigations. It is unclear if circulating ADMA and other methylarginines are associated with incident MetS prospectively.

Methods

We related circulating ADMA, symmetric dimethylarginine (SDMA), L-arginine (ARG) concentrations (measured with a validated tandem mass spectrometry assay) and the ARG/ADMA ratio to MetS and its components in 2914 (cross-sectional analysis, logistic regression; mean age 58 years, 55% women) and 1656 (prospective analysis, Cox regression; mean age 56 years, 59% women) individuals from the Framingham Offspring Study who attended a routine examination.

Results

Adjusting for age, sex, smoking, and eGFR, we observed significant associations of ADMA (direct) and ARG/ADMA (inverse) with odds of MetS (N = 1461 prevalent cases; Odds Ratio [OR] per SD increment 1.13, 95%CI 1.04–1.22; and 0.89, 95%CI 0.82–0.97 for ADMA and ARG/ADMA, respectively). Upon further adjustment for waist circumference, systolic and diastolic blood pressure, glucose, high-density lipoprotein cholesterol, and triglycerides, we observed a positive relation between SDMA and MetS (OR per SD increment 1.15, 95% CI 1.01–1.30) but the other associations were rendered statistically non-significant. We did not observe statistically significant associations between any of the methylarginines and the risk of new-onset MetS (752 incident events) over a median follow-up of 11 years.

Conclusion

It is unclear whether dimethylarginines play an important role in the incidence of cardiometabolic risk in the community, notwithstanding cross-sectional associations. Further studies of larger samples are needed to replicate our findings.

Gut permeability is associated with hypertension and measures of obesity but not with Endothelial Dysfunction in South African youth

Background

Though gut permeability has shown to be associated with measures of obesity and hypertension, its relationship with endothelial dysfunction, an early predictor for cardiovascular diseases remains unknown.

Objective

This study assessed the relationship between hypertension, measures of obesity, gut permeability and endothelial dysfunction.

Methods

A cross-sectional quantitative study which enrolled 151 South African youths was conducted. Anthropometric and blood pressure measurements were performed. Zonulin, a marker for gut permeability; adiponectin, an anti-inflammatory molecule, as well as asymmetric dimethylarginine (ADMA) and Nitric oxide (NO) which are markers for endothelialfunction were assayed.

Results

Approximately eighteen percent (17.88%) of the participants were hypertensive while 40.4% were pre-hypertensive. Adiponectin significantly increased in hypertensive subjects and negatively correlated (p<0.05) with measures of obesity but was not associated with gut permeability and endothelial dysfunction. Increased body mass index (BMI) and visceral fat (VF) predicted reduced adiponectin (inflammation). Zonulin was significantly higher (p<0.05) in hypertensive subjects and positively associated (p<0.05) with systolic blood pressure (SBP) in females. A positive relationship (p<0.05) was observed between zonulin and measurements of obesity. Moreover, zonulin negatively associated (p<0.05) with ADMA but positively associated (p<0.05) with NO in males. Increased VF and waist circumference predicted gut permeability.

Conclusion

Gut permeability was associated with hypertension and measures of obesity but not with markers of endothelial dysfunction in a South African youth population.

The Association Between Uric Acid and Symmetric Dimethylarginine Levels in the Patients Undergoing Twice-weekly Hemodialysis

Background: Uric acid (UA) levels are associated with increased risk of cardiovascular events and mortality in hemodialysis patients. However, there are still conflicting data on the mechanism of increased risks related to uric acid levels. Objectives: This study assessed the association between uric acid levels and symmetric dimethylarginine (SDMA), as a marker of cardiovascular disease, in the subjects undergoing hemodialysis twice weekly. Methods: This was a cross-sectional study conducted in a tertiary hospital in Jakarta, Indonesia. We included all the adults who underwent hemodialysis twice weekly for at least three months in our hospital. Subjects already on uric acid lowering therapy, pregnant or lactating women and those with a history of malignancy were excluded. Uric acid and SDMA levels were measured at the same time in pre-dialysis venous blood samples. Bivariate analysis was performed using the Mann-Whitney U test or one-way ANOVA. Results: A total of 126 subjects were included. The median level of UA was 8.4 mg/dL (IQR: 2.6, min: 4.1, max: 13.6), and 72 subjects (57.14%) had UA levels of 8 mg/dL or higher. The median SDMA level was 535.5 (312.7) mmol/dL (min: 119.7, max: 1895.5). Subjects with UA levels > 8 mg/dL had significantly higher SDMA levels compared to subjects with UA levels < 8 mg/dL (550.1 (IQR: 357.25) vs 491.35 (IQR: 181.1), P: 0.0475). Conclusions: In twice-weekly hemodialysis patients, UA levels above 8 mg/dL were associated with increased SDMA levels.

Whole-Body Cryotherapy Increases the Activity of Nitric Oxide Synthase in Older Men

Aging causes oxidative stress, endothelial dysfunction and a reduction in the bioavailability of nitric oxide. The study aim was to determine whether, as a result of repeated whole-body exposure to cryogenic temperature (3 min −130 °C), there is an increase of inducible nitric oxide synthase (iNOS) concentration in senior subjects (59 ± 6 years), and if this effect is stronger in athletes. In 10 long-distance runners (RUN) and 10 untraining (UTR) men, 24 whole-body cryotherapy (WBC) procedures were performed. Prior to WBC, after 12th and 24th treatments and 7 days later, the concentration of iNOS, asymmetric dimethylarginine (ADMA), 3-nitrotyrosine (3-NTR), homocysteine (HCY), C-reactive protein (CRP) and interleukins such as: IL-6, IL-1β, IL-10 were measured. In the RUN and UTR groups, after 24 WBC, iNOS concentration was found to be comparable and significantly higher (F = 5.95, p < 0.01) (large clinical effect size) compared to before 1st WBC and after 12th WBC sessions. There were no changes in the concentration of the remaining markers as a result of WBC (p > 0.05). As a result of applying 24 WBC treatments, using the every-other-day model, iNOS concentration increased in the group of older men, regardless of their physical activity level. Along with this increase, there were no changes in nitro-oxidative stress or inflammation marker levels.

Understanding the association between endothelial dysfunction and left ventricle diastolic dysfunction in development of coronary artery disease and heart failure

Cardiovascular diseases (CVDs)  have been the most common cause of death worldwide for decades. Until recently the most affected patients were middle-aged and elderly, predominantly men, with more frequent ST elevation myocardial infarction  (STEMI) caused by obstructive coronary artery disease (CAD). However, in the last two decades we have noticed an increased incidence of ischemia with non-obstructive coronary arteries (INOCA), which includes myocardial infarction with non-obstructive coronary arteries (MINOCA) and non-myocardial infarction syndromes, such as microvascular and vasospastic angina, conditions that have been particularly pronounced in women and young adults - the population we considered low-risky till than. Therefore, it has become apparent that for this group of patients conventional methods of assessing the risk of future cardiovascular (CV) events are no longer specific and sensitive enough. Heart failure with preserved ejection fraction (HFpEF) is another disease, the incidence of which has been rising rapidly during last two decades, and predominantly affects elderly population. Although the etiology and pathophysiology of INOCA and HFpEF are complex and not fully understood, there is no doubt that the underlying cause of both conditions is endothelial dysfunction (ED) which further promotes the development of left ventricular diastolic dysfunction (LVDD). Plasma biomarkers of ED, as well as natriuretic peptides (NPs), have been intensively investigated recently, and some of them have great potential for early detection and better assessment of CV risk in the future.

Circulating amino acids and amino acid-related metabolites and risk of breast cancer among predominantly premenopausal women

Known modifiable risk factors account for a small fraction of premenopausal breast cancers. We investigated associations between pre-diagnostic circulating amino acid and amino acid-related metabolites (N = 207) and risk of breast cancer among predominantly premenopausal women of the Nurses' Health Study II using conditional logistic regression (1057 cases, 1057 controls) and multivariable analyses evaluating all metabolites jointly. Eleven metabolites were associated with breast cancer risk (q-value < 0.2). Seven metabolites remained associated after adjustment for established risk factors (p-value < 0.05) and were selected by at least one multivariable modeling approach: higher levels of 2-aminohippuric acid, kynurenic acid, piperine (all three with q-value < 0.2), DMGV and phenylacetylglutamine were associated with lower breast cancer risk (e.g., piperine: ORadjusted (95%CI) = 0.84 (0.77-0.92)) while higher levels of creatine and C40:7 phosphatidylethanolamine (PE) plasmalogen were associated with increased breast cancer risk (e.g., C40:7 PE plasmalogen: ORadjusted (95%CI) = 1.11 (1.01-1.22)). Five amino acids and amino acid-related metabolites (2-aminohippuric acid, DMGV, kynurenic acid, phenylacetylglutamine, and piperine) were inversely associated, while one amino acid and a phospholipid (creatine and C40:7 PE plasmalogen) were positively associated with breast cancer risk among predominately premenopausal women, independent of established breast cancer risk factors.

L-homoarginine is associated with decreased cardiovascular- and all-cause mortality

BACKGROUND

Increasing evidence suggests that L-homoarginine, an endogenous analogue of the amino acid L-arginine, may have beneficial effects on vascular homeostasis. We examined whether L-homoarginine is associated with 10-year risk of all-cause and cardiovascular mortality in a black South African population.

METHODS

We included 669 black South African participants (mean age 59.5 years), 143 of whom died during the 10-year follow-up period. Mortality data were acquired via verbal autopsy. Plasma L-homoarginine (and other related markers) were analysed with liquid chromatography-tandem mass spectrometry.

RESULTS

Survivors had higher L-homoarginine levels compared with nonsurvivors (1.25 µM vs. 0.89 µM; P < .001). Multivariable Cox regression analyses revealed that higher plasma L-homoarginine predicted a reduction in 10-year cardiovascular (hazard ratio [HR] per SD increment, 0.61; 95% CI 0.50 to 0.75) and all-cause (hazard ratio [HR] per SD increment, 0.59; 95% CI 0.41 to 0.84) mortality risk.

CONCLUSION

Higher L-homoarginine levels are associated with reduced risk of 10-year cardiovascular and all-cause mortality. Regulation of L-homoarginine levels as a therapeutic target in the management of cardiovascular disease should be investigated.

Evaluation of Biomarkers in Sepsis: High Dimethylarginine (ADMA and SDMA) Concentrations Are Associated with Mortality

BACKGROUND

As modulators of nitric oxide generation, asymmetric dimethylarginine (ADMA) and symmetric dimethylarginine (SDMA) may play important roles in sepsis. Current data on dimethylarginines are conflicting, and direct comparison data with other biomarkers are limited.

METHODS

Fifty-five patients were included in the final analysis and were divided into 4 groups: infection without sepsis, sepsis, severe sepsis, and septic shock. The first available samples on hospital admission were analyzed for ADMA, SDMA, procalcitonin (PCT), C-reactive protein, heparin binding protein (HBP), zonulin, soluble CD25 (sCD25), and soluble CD163 (sCD163). White blood cell (WBC) counts and lactate results were obtained from the medical record.

RESULTS

There were no statistically significant differences in ADMA and SDMA concentrations among the 4 groups; however, PCT, WBC, HBP, and sCD25 showed statistically significant differences. Lactate only trended toward statistical significance, likely because of limited availability in the medical record. Differences between survivors of sepsis and nonsurvivors at 30 days were highly statistically significant for ADMA and SDMA. Areas under the curve (AUCs) for ROC analysis were 0.88 and 0.95, respectively. There was also a statistically significant difference between survivors of sepsis and nonsurvivors for HBP, lactate, sCD25, and sCD163; however, AUCs for ROC curves were not statistically significantly different from 0.5.

CONCLUSIONS

Analysis of biomarkers other than dimethylarginines were in general agreement with expectations from the literature. ADMA and SDMA may not be specific markers for diagnosis of sepsis; however, they may be useful in short-term mortality risk assessment.

Association Between the Asymmetric Dimethylarginine Levels and Glaucoma Severity: A Cross-Sectional Analysis of the LIGHT Study

Purpose

Asymmetric dimethylarginine (ADMA), a potent endogenous inhibitor of nitric oxide synthase, may be involved in the pathophysiology of glaucoma by dysfunctioning nitric oxide and oxidative stress. The purpose of this study was to determine whether the serum ADMA level is associated with the severity of glaucoma.

Methods

One hundred twenty-five patients with glaucoma (mean age 69.4 years) were analyzed in this cross-sectional study. The severity of glaucoma was determined by the visual field mean deviation in the worse eye; severe, a mean deviation ≤ -12 dB; and mild, a mean deviation > -12 dB. The serum ADMA levels were classified into three groups according to tertiles; low (T1), intermediate (T2), and high group (T3).

Results

The mean serum ADMA levels in the severe glaucoma group was significantly higher than that in the mild glaucoma group (0.41 vs. 0.39 µmol/L; P = 0.031). A significantly higher prevalence of patients with severe glaucoma was found in the T3 group than that in the T1 group (T1, 44.7% and T3, 68.2%; P = 0.018). In the multivariable logistic regression analysis adjusted for the potential confounders, e.g., age, sex, obesity, smoking, hypertension, diabetes, and renal function, the odds ratio for severe glaucoma in the T3 group was significantly higher than that in the T1 group (odds ratio 3.02; 95% confidence interval 1.04 to 8.79; P = 0.043).

Conclusions

A significant association between higher serum ADMA levels and severe glaucoma was found, and this association remained significant after adjusting for the potential confounders.

Comparison of biomarkers of endothelial dysfunction and microvascular endothelial function in patients with primary aldosteronism and essential hypertension

Introduction:

Studies have shown that primary aldosteronism (PA) has a higher risk of cardiovascular events than essential hypertension (EH). Endothelial dysfunction is an independent predictor of cardiovascular events. Whether PA and EH differ in the endothelial dysfunction is uncertain. Our study was designed to investigate the levels of biomarkers of endothelial dysfunction (Asymmetric dimethylarginine, ADMA; E-selectin, and Plasminogen activator inhibitor-1, PAI-1) and assess the microvascular endothelial function in patients with PA and EH, respectively.

Methods:

The biomarkers of endothelial dysfunction were measured by enzyme-linked immunosorbent assay (ELISA). Microvascular endothelial function was evaluated by Pulse amplitude tonometry (PAT).

Results:

Thirty-one subjects with EH and 36 subjects with PA including 22 with aldosterone-producing adenoma (APA) and 14 with idiopathic hyperaldosteronism (IHA) were enrolled in our study. The ADMA levels among the three groups were different (APA 47.83 (27.50, 87.74) ng/ml vs EH 25.08 (22.44, 39.79) ng/ml vs IHA 26.00 (22.23, 33.75) ng/ml; p = 0.04), however, when the APA group was compared with EH and IHA group, there was no statistical significance (47.83 (27.50, 87.74) ng/ml vs 25.08 (22.44, 39.79) ng/ml for EH, p = 0.11; 47.83 (27.50, 87.74) ng/ml vs IHA 26.00 (33.75) ng/ml, p = 0.07). The results of ADMA levels are presented as Median (p25, p75). Whereas, levels of PAI-1 and E-selectin, microvascular endothelial function were not significantly different between PA and EH subjects.

Conclusions:

Our study shows no significant differences between PA and EH in terms of biomarkers of endothelial dysfunction and microvascular endothelial function. The microvascular endothelial function of PA and EH patients is comparable.

Cardiovascular Disease in Nonalcoholic Steatohepatitis: Screening and Management

Purpose of Review

The global burden of non-alcoholic steatohepatitis (NASH) as a major cause of chronic liver disease continues to rise. Cardiovascular disease (CVD) is a leading cause of morbidity and mortality in this patient population. The current review summarizes recent advances in the understanding of CVD in NASH and strategies for screening and management.

Recent findings

Large genetic epidemiological studies support the intricate role of the metabolic syndrome in the pathophysiology of CVD risk in patients with NASH. Atherosclerotic CVD risk scores can predict elevated CV risk in NASH, but additional work is necessary to refine risk stratification and to guide optimal management. New antidiabetic agents may offer benefit in treating steatosis and reducing CV morbidity in NASH.

Summary

Achieving improved outcomes in patients with NASH requires that future efforts focus on optimizing methods for CVD screening and designing clinical trials with long-term cardiovascular endpoints in mind.

Cardiovascular Risk Factors and Their Relationship with Vascular Dysfunction in South African Children of African Ancestry

Vascular dysfunction is known to be an initiator of the development and progression of cardiovascular diseases (CVDs). However, there is paucity of information on the relationship of vascular dysfunction with cardiovascular risk factors in children of African ancestry. This study investigated the relationship between cardiovascular risk factors and vascular function in South African children of African ancestry. A cross-sectional study on 6–9-year-old children in randomly selected rural and urban schools of the Eastern Cape Province of South Africa was conducted. General anthropometric indices were measured, followed by blood pressure (BP) measurements. The pulse wave velocity (PWV) was measured using a Vicorder. Albumin to creatinine ratio (ACR), asymmetric dimethylarginine (ADMA), 8-hydroxy-2deoxyguanosine (8-OHdG) and thiobarbituric acid reactive substance (TBARS) were assayed in urine. Children from urban settings (10.8%) had a higher prevalence of overweight/obesity than their rural counterparts (8.5%) while the prevalence of elevated/high blood pressure was higher in rural (23.2%) than urban children (19.0%). Mean arterial blood pressure (MAP) and diastolic blood pressure (DBP) increased with increasing PWV (p < 0.05). Body mass index (BMI), diastolic blood pressure (DBP) and mean arterial blood pressure (MAP) positively associated (p < 0.05) with PWV. Creatinine, albumin and ACR significantly (p < 0.005) increased with increasing ADMA. ADMA associated positively (p < 0.05) with creatinine and 8-OHdG. In conclusion, vascular dysfunction was associated with obesity, high blood pressure, oxidative stress and microalbuminuria in South African children of African ancestry.

The Importance of a New Cardiovascular Risk Factor - Asymmetric Dimethylarginine

In the past years, scientific research has highlighted the presence of a new cardiovascular risk factor, the implications of which have not been sufficiently studied so far. It is different from conventional risk factors because it acts independently at the endothelial level, having important proatherogenic properties. Through its action, this risk factor leads to increased oxidative stress and promotes the onset of atherosclerosis faster than other well-known risk factors so far. Asymmetric dimethylarginine (ADMA) is a methylprotein that arises from posttranslational methylation of proteins. Its importance has emerged in recent years, when the rate of cardiovascular mortality among patients with chronic kidney disease has been high. The distinctive element of this risk factor compared to other well-known ones is given by its ability to compete directly with nitric oxide synthase, being its strongest endogenous inhibitor, with strong proatherogenic attributions. Given that ADMA has tight correlations with atherogenesis and endothelial damage, its assessment should be taken into consideration for any patient who has been recently diagnosed with high blood pressure.

Combined oral contraceptives modify the effect of smoking on inflammatory cellular indexes and endothelial function in healthy subjects

Little information is available on the influence of sex in combination with smoking habits and combined oral contraceptives (COC) use on cellular inflammatory indexes such as neutrophil/lymphocyte ratio (NLR), derived NRL (dNLR), platelet/lymphocyte ratio (PLR), monocyte/lymphocyte ratio (MLR), mean platelet volume/platelet count (MPV/PLT), aggregate inflammation systemic index (AISI), and systemic inflammation response index (SIRI), which are cost-effective biomarkers to assessing inflammation. Therefore, the effect of COC was studied alone or in association with smoking and compared with results from healthy COC-free women and men. Furthermore, the association of cellular inflammatory indexes with endothelial function (arginine (Arg), asymmetric dimethylarginine (ADMA), symmetric dimethylarginine (SDMA) and lipid peroxidation (malondialdehyde MDA) biomarkers was evaluated. Blood was collected for hematological and biochemical analysis, which were used to calculate PLR, NLR, dNLR, MLR, MPV/PLT, AISI, and SIRI. Serum samples were assayed for Arg, ADMA, SDMA, and MDA. Monocytes, MLR, SIRI, and MPV/PLT were higher in men, while PLT count was higher in women. COC use increased lymphocytes and lowered PLR and MLR. Smoking reduced sexually divergent parameters, especially in COC users: smoking and non-smoking COC-free women displayed six divergent parameters, while COC users displayed only two (monocytes and MPV). In addition, COC affected endothelial function, reducing ADMA and Arg. Moreover, COC-free women had lower Arg levels than men. In conclusion, COC use strongly influence the effects of tobacco smoking, which are sex and parameter specific. Further, these data stress that COC use and smoking attitude select different cohorts indicating that sex and gender studies need intersectionality.

Association of Asymmetric Dimethylarginine and Nitric Oxide with Cardiovascular Risk in Patients with End-Stage Liver Disease

BACKGROUND AND OBJECTIVES

Endothelial dysfunction has been proposed to be an underlying mechanism of the pronounced cardiovascular morbidity in end-stage liver disease (ESLD), but clinical evidence is still limited. In this study, we investigated the association of circulating levels of asymmetric dimethylarginine (ADMA) and nitric oxide (NO) with estimated cardiovascular risk in patients with ESLD awaiting liver transplantation.

MATERIALS AND METHODS

ADMA and NO levels were measured in the sera of 160 adult ESLD patients. The severity of hepatic dysfunction was assessed by the model for end-stage liver disease (MELD) score. The cardiovascular risk was estimated with the European Society of Cardiology Systematic Coronary Risk Estimation (SCORE) index, which was used to dichotomize patients in the subgroups depicting higher and lower cardiovascular risk.

RESULTS

Severe hepatic dysfunction (MELD ≥ 18) was present in 38% of the patients, and a higher cardiovascular risk was present in almost half of the patients (N = 74). ADMA and NO both significantly increased with the progression of liver disease and were independently associated with higher cardiovascular risk. Fasting glucose also independently predicted a higher cardiovascular risk, while HDL cholesterol and the absence of concomitant hepatocellular carcinoma were protective factors.

CONCLUSIONS

These results suggest a remarkable contribution of the deranged arginine/NO pathway to cardiovascular risk in patients with end-stage liver disease.

L-Arginine-Nitric Oxide-Asymmetric Dimethylarginine Pathway and the Coronary Circulation: Translation of Basic Science Results to Clinical Practice

By 1980, it was thought that we already knew most of the major mechanisms regulating vascular tone. However, after the somewhat serendipity discovery that endothelium is involved in mediation of relaxation to acetylcholine, a whole new world opened up and we had to rewrite our concept regarding vascular function and its regulation (not to mention many other fields). The new player was an endothelium derived relaxing factor, which molecular constitution has been identified to be nitric oxide (NO). This review summarizes the major molecular steps concerning how NO is synthetized from L-arginine. Also, the fate of L-arginine is described via the arginase and methylation pathways; both of them are affecting substantially the level and efficacy of NO. In vitro and in vivo effects of L-arginine are summarized and controversial clinical findings are discussed. On the basis of the use of methylated L-arginines, the vasomotor effects of endothelial NO released to agonists and increases in flow/wall shear stress (a major biological stimulus) is summarized. In this review the role of NO in the regulation of coronary vascular resistance, hence blood flow, is delineated and the somewhat questionable clinical use of NO donors is discussed. We made an attempt to summarize the biosynthesis, role, and molecular mechanisms of endogenously produced methylated L-arginine, asymmetric dimethylarginine (ADMA) in modulating vascular resistance, affecting the function of the heart. Additionally, the relationship between ADMA level and various cardiovascular diseases is described, such as atherosclerosis, coronary artery disease (CAD), ischemia/reperfusion injuries, and different types of coronary revascularization. A novel aspect of coronary vasomotor regulation is identified in which the pericardial fluid ADMA and endothelin play putative roles. Finally, some of the open possibilities for future research on L-arginine-NO-ADMA signaling are highlighted.

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.

[Asymmetric dimethylarginine (ADMA) in retinal vein occlusion-Results from the Gutenberg RVO study]

BACKGROUND

Asymmetric dimethylarginine (ADMA) is considered an independent cardiovascular risk factor (cvRF) and thus represents a potential new biomarker for retinal vein occlusion (RVO).

METHODS

Overall, 92 patients with RVO and the same number of matched controls were included in the Gutenberg RVO study. All patients underwent a standardized examination for cvRF at the study center of the population-based Gutenberg health study (GHS) as well as ophthalmological examinations and intensive laboratory tests. This article presents a substudy of patients (≤65 years old) and the controls in whom ADMA was additionally determined by high performance liquid chromatography (HPLC) at baseline and 4-6 weeks later.

RESULTS

Out of 44 patients with RVO 22 had central retinal vein occlusion (CRVO), 15 had branch retinal vein occlusion (BRVO) and 7 had hemiretinal vein occlusion (hemi-RVO). The ADMA levels were 0.383 ± 0.094 µM (mean ± standard deviation) in RVO patients at baseline and 0.380 ± 0.093 µM (p = 0.514, initial vs. follow-up) after the follow-up period versus 0.360 ± 0.077 µM (p = 0.175, controls vs. RVO) in controls (n = 44). Arterial hypertension was the most prevalent risk factor in 22 (50%) of the patients and in 11 (25%) of the controls (odds ratio, OR 2.77, 95% confidence interval, CI 0.97-7.95; p = 0.058). The ADMA values above the 95th percentile (>0.530 µM) were detected in 4 patients with RVO (9.1%) but not in any of the controls (p = 0.041, RVO vs. controls).

CONCLUSION

Hypertension is the most important risk factor for RVO. Due to the high number of hypertensive patients in the cohort, the relevance of ADMA as an independent risk factor could neither be confirmed nor disproved.

Atrial Myopathy Underlying Atrial Fibrillation

While AF most often occurs in the setting of atrial disease, current assessment and treatment of patients with AF does not focus on the extent of the atrial myopathy that serves as the substrate for this arrhythmia. Atrial myopathy, in particular atrial fibrosis, may initiate a vicious cycle in which atrial myopathy leads to AF, which in turn leads to a worsening myopathy. Various techniques, including ECG, plasma biomarkers, electroanatomical voltage mapping, echocardiography, and cardiac MRI, can help to identify and quantify aspects of the atrial myopathy. Current therapies, such as catheter ablation, do not directly address the underlying atrial myopathy. There is emerging research showing that by targeting this myopathy we can help decrease the occurrence and burden of AF.

Comprehensive arginine metabolomics and peripheral vasodilatory capacity in rheumatoid arthritis: A monocentric cross-sectional study

BACKGROUND

The relationship between plasma arginine metabolites influencing vascular homeostasis and peripheral vasodilatory capacity in rheumatoid arthritis (RA) patients is not known.

METHODS

l-arginine (Arg), monomethyl-l-arginine (MMA), l-homoarginine (hArg), asymmetric dimethyl-l-arginine (ADMA), symmetric dimethyl-l-arginine, and l-citrulline (Cit) were measured by liquid chromatography tandem mass spectrometry (LC-MS/MS) in 164 RA patients and 100 age- and sex-matched healthy controls without previous cardiovascular events. Log-transformed reactive hyperemia index (Ln-RHI) evaluated by flow-mediated pulse amplitude tonometry (PAT, EndoPAT2000 device) was assessed as surrogate measure of peripheral vasodilatory capacity in RA patients. Ln-RHI values <0.51 indicated peripheral endothelial dysfunction (ED). The relationship between plasma arginine metabolite concentrations, RA descriptors and peripheral vasodilatory capacity was evaluated by bivariate correlation and regression analyses.

RESULTS

Plasma ADMA concentrations were significantly higher, and plasma hArg concentrations significantly lower, in RA patients than in controls (0.53 ± 0.09 vs 0.465 ± 0.07 μmol/L and 1.50 ± 0.60 vs 1.924 ± 0.78 μmol/L, respectively; p < 0.001 for both comparisons). Bivariate correlation analysis demonstrated no significant correlation between arginine metabolites and disease descriptors. In regression analysis in RA patients, higher plasma ADMA concentrations were independently associated with presence of ED [OR(95% CI) = 77.3(1.478-4050.005), p = 0.031] and lower Ln-RHI [B coefficient(95% CI) = -0.57(-1.09 to -0.05), p = 0.032].

CONCLUSIONS

ADMA was significantly, albeit weakly, associated with impaired microcirculatory vasodilatory capacity and peripheral endothelial dysfunction in RA. This suggests an important pathophysiological role of this metabolite in the vascular alterations observed in this patient group.

DDAH1 regulates apoptosis and angiogenesis in human fetal pulmonary microvascular endothelial cells

Nitric Oxide (NO) is an endogenous pulmonary vasodilator produced by endothelial NO synthase (eNOS). Asymmetric dimethyl L‐arginine (ADMA) is an endogenous inhibitor of eNOS activity. In endothelial cells, ADMA is hydrolyzed to L‐citrulline primarily by dimethylarginine dimethyl‐aminohydrolase‐1 (DDAH1). We tested the hypothesis that DDAH1 expression is essential for maintaining NO production in human fetal pulmonary microvascular endothelial cells (hfPMVEC), such that knockdown of DDAH1 expression will lead to decreased NO production resulting in less caspase‐3 activation and less tube formation. We found that hfPMVEC transfected with DDAH1 siRNA had lower NO production than control, with no difference in eNOS protein levels between groups. hfPMVEC transfected with DDAH1 siRNA had lower protein levels of cleaved caspase‐3 and ‐8 than control. Both DDAH1 siRNA‐ and ADMA‐treated hfPMVEC had greater numbers of viable cells than controls. Angiogenesis was assessed using tube formation assays in matrigel, and tube formation was lower after either DDAH1 siRNA transfection or ADMA treatment than controls. Addition of an NO donor restored cleaved caspase‐3 and ‐8 protein levels after DDAH1 siRNA transfection in hfPMVEC to essentially the levels seen in scramble control. Addition of a putative caspase‐3 inhibitor to DDAH1 siRNA transfected and NO‐donor treated cells led to greater numbers of viable cells and far less angiogenesis than in any other group studied. We conclude that in hfPMVEC, DDAH1 is central to the regulation of NO‐mediated caspase‐3 activation and the resultant apoptosis and angiogenesis. Our findings suggest that DDAH1 may be a potential therapeutic target in pulmonary hypertensive disorders.

Effect of a lifestyle intervention program with energy-restricted Mediterranean diet and exercise on the serum polyamine metabolome in individuals at high cardiovascular disease risk: a randomized clinical trial

BACKGROUND

Many food items included in the Mediterranean diet (MedDiet) are rich in polyamines, small aliphatic amines with potential cardioprotective effects. The consumption of a MedDiet could increase polyamine concentrations. Based on experimental models, polyamine concentrations may be also influenced by physical activity (PA).

OBJECTIVES

We aimed to evaluate whether an intervention based on an energy-restricted MedDiet (er-MedDiet) and PA promotion, in comparison with an energy-unrestricted MedDiet and traditional health care, influences the serum pattern of polyamines and related metabolites in subjects at high risk of cardiovascular disease (CVD).

METHODS

This was a substudy from the PREDIMED-Plus trial, an ongoing randomized clinical trial including 6874 participants allocated either to an intensive weight-loss lifestyle intervention based on er-MedDiet, PA promotion, and behavioral support (er-MedDiet + PA group), or to an energy-unrestricted MedDiet and traditional health care group (MedDiet group). A total of 75 patients (n = 38, er-MedDiet + PA group; n = 37, MedDiet group) were included in this study. Serum concentrations of arginine, ornithine, polyamines, and acetyl polyamines at baseline and 26 wk of intervention were measured by an ultra-high-performance LC-tandem MS platform.

RESULTS

At week 26, study groups had similar adherence to the MedDiet but patients randomly assigned to the er-MedDiet + PA group showed significantly lower mean energy intake (-340.3 kcal/d; 95% CI: -567.3, -113.4 kcal/d; P = 0.004), higher mean PA (1290.6; 95% CI: 39.9, 2541.3 metabolic equivalent tasks · min/d; P = 0.043), and higher mean decrease in BMI (in kg/m2) (-1.3; 95% CI: -1.8, -0.6; P < 0.001) than the MedDiet group. However, no significant differences in serum polyamines or related metabolites were found between study groups after 26 wk of intervention and no significant between-group differences were found in glycated hemoglobin, HDL-cholesterol, or triglyceride concentrations.

CONCLUSIONS

In individuals at high CVD risk, an er-MedDiet with increased PA did not result in significant changes of serum concentrations of polyamines or related metabolites in comparison with an energy-unrestricted MedDiet and no increase in PA. This trial was registered at isrctn.com as ISRCTN89898870.

Targeted ultra-performance liquid chromatography/tandem mass spectrometric quantification of methylated amines and selected amino acids in biofluids

RATIONALE

Methylated amino compounds and basic amino acids are important analyte classes with high relevance in nutrition, physical activity and physiology. Reliable and easy quantification methods covering a variety of metabolites in body fluids are a prerequisite for efficient investigations in the field of food and nutrition.

METHODS

Targeted ultra-performance liquid chromatography/tandem mass spectrometric (UHPLC/MS) analysis was performed using HILIC separation and timed ESI-MRM detection, combined with a short sample preparation. Calibration in urine and blood plasma was achieved by matrix-matched standards, isotope-labelled internal standards and standard addition. The method was fully validated and the performance was evaluated using a subset from the Karlsruhe Metabolomics and Nutrition (KarMeN) study.

RESULTS

Within this method, a total of 30 compounds could be quantified simultaneously in a short run of 9 min in both body fluids. This covers a variety of free amino compounds which are present in very different concentrations. The method is easy, precise and robust, and has a broad working range. As a proof of principle, literature-based associations of certain metabolites with dietary intake of respective foods were clearly confirmed in the KarMeN subset.

CONCLUSIONS

Overall, the method turned out to be well suited for application in nutrition studies, as shown for the example of food intake biomarkers in KarMeN. Application to a variety of questions such as food-related effects or physical activity will support future studies in the context of nutrition and health.