The relationship between plasma asymmetrical dimethyl-L-arginine and inflammation and adhesion molecule levels in subjects with normal, impaired, and diabetic glucose tolerance

Is Intravenous Dextrose Infusion During Emergence From Anesthesia Effective in Improving the PONV in Gynecologic Laparoscopy? A Randomized Controlled Trial

STUDY OBJECTIVE

This study aimed to explore the relationship between intravenous 5% dextrose infusion during emergence from anesthesia to postoperative nausea and vomiting (PONV) in patients after gynecologic laparoscopic surgery.

DESIGN

This was a double-blind randomized controlled trial. Participants were randomized into the experimental group and control group using a computer-generated random number generator. Intervenors and measurers were blinded to group assignments of the study.

SETTING

A single academic tertiary medical center.

PATIENTS

Patients undergoing gynecologic laparoscopic surgery.

INTERVENTIONS

On completion of surgery, participants were randomized into the test group (receive 5% dextrose) and control group (receive Ringer's lactate solution).

MEASUREMENTS AND MAIN RESULTS

The primary outcome of the present study was the incidence of PONV. Other outcomes included postoperative rescue analgesic and rescue antiemetic, postoperative pain response, and recovery time of postanesthesia care unit. Baseline characteristics were statistically similar between the 2 groups of participants. There were 49 of 105 patients experienced PONV within 24 hours postoperatively. The overall incidence of PONV within 24 hours postoperatively was not significantly different (45.5% vs 48%; relative risk [RR], 0.95; 95% confidence interval [CI], 0.67-1.37; p = .794). However, fewer patients experienced PONV in the test group than in the control group during 0 to 1 hours (6.0% vs 20.0%; RR, 0.85; 95% CI, 0.73-0.99; p = .024) and 1 to 3 hours (14.5% vs 32.0%; RR, 0.80; 95% CI, 0.64-0.99; p = .033) postoperatively. In addition, recovery time in the postanesthesia care unit was less in the test group (17.07 ± 6.36 vs 22.04 ± 7.33; mean difference, -4.97; 95% CI, -7.62 to -2.32; p <.001) and pain score was lower in the test group during 0 to 0.5 hours postoperatively (2.29 ± 1.74 vs 3.08 ± 1.64; mean difference, -0.79; 95% CI, -1.45 to -0.13; p = .019).

CONCLUSION

In patients after gynecologic laparoscopic surgery, postanesthesia 5% dextrose infusion may be useful in improving the early management of PONV and pain response and may warrant further study.

Role of ADMA in the pathogenesis of microvascular complications in type 2 diabetes mellitus

Diabetic microangiopathy is a typical and severe problem in diabetics, including diabetic retinopathy, diabetic nephropathy, diabetic neuropathy, and diabetic cardiomyopathy. Patients with type 2 diabetes and diabetic microvascular complications have significantly elevated levels of Asymmetric dimethylarginine (ADMA), which is an endogenous inhibitor of nitric oxide synthase (NOS). ADMA facilitates the occurrence and progression of microvascular complications in type 2 diabetes through its effects on endothelial cell function, oxidative stress damage, inflammation, and fibrosis. This paper reviews the association between ADMA and microvascular complications of diabetes and elucidates the underlying mechanisms by which ADMA contributes to these complications. It provides a new idea and method for the prevention and treatment of microvascular complications in type 2 diabetes.

Oxidative Stress and Arginine/Nitric Oxide Pathway in Red Blood Cells Derived from Patients with Prediabetes

The effects of the oral glucose tolerance test (OGTT) on red blood cells (RBCs) have not been thoroughly investigated, although it is known that the ingestion of 75 g of glucose during OGTT results in a systemic state of inflammation and oxidative stress. Therefore, we evaluated the effect of OGTT on oxidative stress and L-arginine/Nitric Oxide (L-Arg/NO) metabolic pathway in RBCs obtained from patients with prediabetes. Blood samples were collected from all participants before (T0) and at 10 (T1), 20 (T2), 30 (T3), 60 (T4), 90 (T5), 120 (T6), 150 (T7), and 180 (T8) minutes after glucose loading. Results showed a significant increase in oxidative stress status characterized by a rise in the GSSG/GSH ratio at T4 and T6 that increased in parallel with a reduction of NO production in RBCs. In addition, in this time frame, increased exposure of phosphatidylserine on RBCs membrane was observed. These metabolic modifications were rescued at T8, together with an increase in activated RBC NO synthase expression. These findings provide a possible explanation of the phenomena occurring after glucose loading and suggest that, even in the early stages of diabetes, it may be important to avoid acute variations in glycemia in order to prevent diabetic complications.

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.

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.

A Protein/Lipid Preload Attenuates Glucose-Induced Endothelial Dysfunction in Individuals with Abnormal Glucose Tolerance

Postprandial hyperglycemia interferes with vascular reactivity and is a strong predictor of cardiovascular disease. Macronutrient preloads reduce postprandial hyperglycemia in subjects with impaired glucose tolerance (IGT) or type 2 diabetes (T2D), but the effect on endothelial function is unknown. Therefore, we examined whether a protein/lipid preload can attenuate postprandial endothelial dysfunction by lowering plasma glucose responses in subjects with IGT/T2D. Endothelial function was assessed by the reactive hyperemia index (RHI) at fasting, 60 min and 120 min during two 75 g oral glucose tolerance tests (OGTTs) preceded by either water or a macronutrient preload (i.e., egg and parmesan cheese) in 22 volunteers with IGT/T2D. Plasma glucose, insulin, glucagon-like peptide-1 (GLP-1), glucose-dependent insulinotropic polypeptide (GIP), glucagon, free fatty acids, and amino acids were measured through each test. RHI negatively correlated with fasting plasma glucose. During the control OGTT, RHI decreased by 9% and its deterioration was associated with the rise in plasma glucose. The macronutrient preload attenuated the decline in RHI and markedly reduced postprandial glycemia. The beneficial effect of the macronutrient preload on RHI was proportional to the improvement in glucose tolerance and was associated with the increase in plasma GLP-1 and arginine levels. In conclusion, a protein/lipid macronutrient preload attenuates glucose-induced endothelial dysfunction in individuals with IGT/T2D by lowering plasma glucose excursions and by increasing GLP-1 and arginine levels, which are known regulators of the nitric oxide vasodilator system.

Circulating Vascular Cell Adhesion Molecule-1 (VCAM-1) and Intercellular Adhesion Molecule-1 (ICAM-1): Relationship with carotid artery elasticity in patients with impaired glucose regulation (IGR)

OBJECTIVE

To investigate the relations of circulating adhesion molecule vascular cell adhesion molecule-1 (VCAM-1) and intercellular adhesion molecule-1 (ICAM-1) with carotid artery elasticity in patients with impaired glucose regulation (IGR).

METHODS

A total of 208 subjects were enrolled from January 2013 to March 2014. One hundred forty-eight were IGR patients, and 60 had normal glucose tolerance (NGT). Carotid intima-media thickness (IMT), carotid artery pressure-strain elasticity coefficient (Eρ), stiffness (β), arterial compliance (AC), and pulse wave velocity (PWVβ), as well as blood pressure, body mass index, blood glucose, blood lipids, insulin resistance index, VCAM-1, and ICAM-1 were measured and compared between IGR and NGT patients.

RESULTS

Eρ, β and PWVβ were significantly higher in the IGR group than in the NGT group (P<0.05), but the IMT showed no significant difference (P>0.05). VCAM-1 and ICAM-1 were significantly higher in the IGR group than in the NGT group (P<0.05). VCAM-1 and ICAM-1 were positively correlated with Eρ, β, and PWVβ and negatively correlated with AC in IGR patients.

CONCLUSIONS

Changes in carotid artery elasticity and endothelial dysfunction are found in patients with IGR. Early comprehensive intervention should be performed in such IGR populations.

Exploratory metabolomics of metabolic syndrome: A status report

Metabolic syndrome (MetS) is as a cluster of cardio-metabolic factors that greatly increase the risk of chronic diseases such as type II diabetes mellitus and atherosclerotic cardiovascular disease. In the United States, obesity, physical inactivity, aging, and genetics (to a minor extent) have arisen as risk factors for developing MetS. Although 35% of American adults suffer from MetS, its pathogenesis largely remains unknown. Worse, there is a lack of screening and optimum therapy for this disease. Researchers have consequently turned towards metabolomics to identify biomarkers to better understand MetS. The purpose of this review is to characterize various metabolites and their potential connections to MetS. Numerous studies have also characterized MetS as a disease of increased inflammation, and therefore this review also explores how metabolites play a role in various inflammatory pathways. Our review explores a broad range of metabolites including biogenic amines, branched chain amino acids, aromatic amines, phosphatidylcholines, as well as a variety of other molecules. We will explore their biochemical pathways and their potential role in serving as biomarkers.

Association of circulatory asymmetric dimethylarginine (ADMA) with diabetic nephropathy in Asian Indians and its causative role in renal cell injury

AIM

Asymmetric dimethylarginine (ADMA) is involved in the regulation of nitric oxide synthesis and in the maintenance of vascular tone and structure. But the role and status of ADMA in diabetes induced kidney injury is not clear. Hence this study is investigating the role of ADMA in the progression of kidney injury and its circulatory status in Asian Indians with and without diabetic nephropathy.

METHODS

Recruited study subjects were divided into normal glucose tolerance (NGT), type 2 diabetes mellitus (T2DM) and T2DM with micro or macroalbuminuria. Albuminuria was calculated using urinary albumin and creatinine ratio (UACR). ADMA was measured using ELISA. Kidney cell damage in terms of fibrotic markers and ADMA metabolism in terms of DDAH activity were investigated in kidney fibroblasts and mesangial cells.

RESULTS

There was a significant elevation in plasma ADMA levels in micro and macroalbuminuric diabetic patients. We found a significant positive correlation between ADMA and UACR, serum creatinine, HbA1C and fasting plasma glucose. A cut-off value of ADMA, 0.666μM/l had a sensitivity and specificity of 70.0% and 65.6%, respectively for detecting diabetic nephropathy. DDAH activity was significantly decreased and fibrotic markers such as fibronectin and α-SMA were significantly increased upon high glucose and ADMA treatment.

CONCLUSION

We are suggesting a causative role of ADMA in the development of kidney injury in terms of renal fibrosis and also a cut point of 0.666μM/l of plasma ADMA level appears to be a predictive risk threshold for diabetic nephropathy in south Asian Indian population.

Asymmetric dimethylarginine and all-cause mortality: a systematic review and meta-analysis

Asymmetrical dimethylarginine (ADMA), an endogenous inhibitor of nitric oxide synthase (NOS), impairs the beneficial effect of NO. The predictive value of ADMA for all-cause mortality remains controversial, though it is important in the development of cardiovascular disease (CVD) and progression to dialysis in renal disease. This systematic review and meta-analysis was conducted to investigate the association between circulating ADMA and all-cause mortality. Studies with data pertinent to the association between circulating ADMA and all-cause mortality were reviewed and OR, HR or RR with 95% CI derived from multivariate Cox's proportional-hazards analysis were extracted. A total of 34 studies reporting 39137 participants were included in final analysis. The results demonstrated that circulating ADMA was independently associated with all-cause mortality (RR = 1.27, 95% CI: 1.20-1.34). The association was still statistically significant in patients with pre-existing renal disease (RR = 1.30, 95% CI: 1.19-1.43) and pre-existing CVD (RR = 1.26, 95% CI: 1.16-1.37). In those without pre-existing renal or CVD, ADMA also predicted all-cause mortality (RR = 1.31, 95% CI: 1.13-1.53). The present study suggests a positive association of circulating ADMA with all-cause mortality. Further studies are needed to investigate the effects of interventions on ADMA, and the value of ADMA as a biomarker.

Decreasing high postprandial stearic acid in impaired fasting glucose by dietary regulation

BACKGROUND/OBJECTIVES

The objective of this study was to determine the postprandial change in free fatty acid (FFA) profiles in subjects with impaired fasting glucose (IFG), and to evaluate the effect of low glycemic index (GI) load on postprandial FFA profiles and inflammation.

SUBJECTS/METHODS

First, 50 IFG and 50 healthy subjects were recruited; and 2 -h postprandial changes in FFA profiles were determined. Second, the 50 IFG subjects then received three different loads: glucose load (GL), high glycemic index (HGI) load and low glycemic index (LGI) load, respectively. FFA profile, glucose, insulin, glucagon-like peptide 1 (GLP-1) and inflammatory biomarkers were assayed at 0, 30, 60, 90 and 120 min.

RESULTS

Postprandial stearic acid (C18:0) increased compared with baseline in all subjects, whereas the change in postprandial C18:0 was more marked in IFG subjects than in healthy subjects. Compared with subjects who received the GL and HGI load, the area under the curve for insulin, GLP-1, C18:0 and tumor necrosis factor-alpha significantly decreased and adiponectin increased in subjects who received the LGI load.

CONCLUSIONS

The rise in postprandial C18:0 in IFG subjects was inhibited by LGI load.

Postprandial Dysmetabolism and Oxidative Stress in Type 2 Diabetes: Pathogenetic Mechanisms and Therapeutic Strategies

Postprandial dysmetabolism in type 2 diabetes (T2D) is known to impact the progression and evolution of this complex disease process. However, the underlying pathogenetic mechanisms still require full elucidation to provide guidance for disease prevention and treatment. This review focuses on the marked redox changes and inflammatory stimuli provoked by the spike in blood glucose and lipids in T2D individuals after meals. All the causes of exacerbated postprandial oxidative stress in T2D were analyzed, also considering the consequence of enhanced inflammation on vascular damage. Based on this in-depth analysis, current strategies of prevention and pharmacologic management of T2D were critically reexamined with particular emphasis on their potential redox-related rationale.

Clinical evaluation of extracellular ADMA concentrations in human blood and adipose tissue

Circulating asymmetrical dimethylarginine (ADMA), an endogenous inhibitor of nitric oxide synthesis, has been proposed as a biomarker for clinical outcome. Dimethylarginine dimethylaminohydrolase (DDAH) is the main enzyme responsible for ADMA metabolism and elimination. Adipose tissue ADMA concentrations and DDAH activity and their role in diabetes and obesity have not yet been investigated. In this study, we evaluated clinical microdialysis in combination with a sensitive analytical method (GC-MS/MS) to measure ADMA concentrations in extracellular fluid. Adipose tissue ADMA concentrations were assessed before and during an oral glucose tolerance test in lean healthy subjects and subjects with diabetes (n = 4 each), and in morbidly obese subjects before and after weight loss of 30 kg (n = 7). DDAH activity was determined in subcutaneous and visceral adipose tissue obtained during laparoscopic surgery (n = 5 paired samples). Mean interstitial ADMA concentrations did not differ between study populations (healthy 0.17 ± 0.03 μM; diabetic 0.21 ± 0.03 μM; morbidly obese 0.16 ± 0.01 and 0.17 ± 0.01 μM before and after weight loss, respectively). We did not observe any response of interstitial ADMA concentrations to the oral glucose challenge. Adipose tissue DDAH activity was negligible compared to liver tissue. Thus, adipose tissue ADMA plays a minor role in NO-dependent regulation of adipose tissue blood flow and metabolism.

Cardiovascular risk in autoimmune disorders: role of asymmetric dimethylarginine

Mounting evidence indicates that cardiovascular events are a main cause of excessive mortality of autoimmune disorders like type I diabetes mellitus and rheumatic diseases. Inflammation and endothelial dysfunction, independent predictors to cardiovascular disease, are hallmarks of autoimmunity. Asymmetric dimethylarginine (ADMA), an endogenous nitric oxide synthase inhibitor, can cause or contribute to the inflammatory syndrome and endothelial dysfunction. Recently, elevated ADMA levels have been demonstrated in many autoimmune diseases, suggesting that ADMA might play an important role for the associated manifestations of cardiovascular disease. In the review, we discuss the role of ADMA in the excessive cardiovascular morbidity and mortality associated with autoimmune diseases.

Pioglitazone delays proximal tubule dysfunction and improves cerebral vessel endothelial dysfunction in normoalbuminuric people with type 2 diabetes mellitus

AIM

The renal and cerebral protective effects of pioglitazone were assessed in normoalbuminuric patients with type 2 diabetes mellitus (DM).

METHODS

A total of 68 normoalbuminuric type 2 DM patients were enrolled in a one-year open-label randomized controlled trial: 34 patients (pioglitazone-metformin) vs. 34 patients (glimepiride-metformin). All patients were assessed concerning urinary albumin: creatinine ratio (UACR), urinary alpha1-microglobulin, urinary beta2-microglobulin, plasma asymmetric dymethyl-arginine (ADMA), GFR, hsC-reactive protein, fibrinogen, HbA1c; pulsatility index, resistance index in the internal carotid artery and middle cerebral artery, intima-media thickness in the common carotid artery; cerebrovascular reactivity was evaluated through the breath-holding test.

RESULTS

At 1 year there were differences between groups regarding ADMA, urinary beta2-microglobulin, urinary alpha1-microglobulin, parameters of inflammation, serum creatinine, GFR, UACR, the cerebral haemodynamic indices. Significant correlations were found between alpha 1-microglobulin-UACR (R(2)=0.143; P=0.001) and GFR (R(2)=0.081; P=0.01); beta2-microglobulin-UACR (R(2)=0.241; P=0.0001) and GFR (R(2)=0.064; P=0.036); ADMA-GFR (R(2)=0.338; P=0.0001), parameters of inflammation, HbA1c, duration of DM, cerebral indices. There were no correlations between ADMA-UACR, urinary alpha1-microglobulin and beta2-microglobulin.

CONCLUSION

Proximal tubule (PT) dysfunction precedes albuminuria and is dissociated from endothelial dysfunction in patients with type 2 DM. Pioglitazone delays PT dysfunction and improves cerebral vessels endothelial dysfunction in normoalbuminuric patients with type 2 DM.

Inflammation and asymmetric dimethylarginine for predicting death and cardiovascular events in ESRD patients

BACKGROUND

Endothelial dysfunction as assessed by asymmetric dimethylarginine (ADMA) and inflammation has been consistently linked to atherosclerosis, death, and cardiovascular (CV) events in ESRD patients. Inflammation amplifies the effect of ADMA on the severity of atherosclerosis in ESRD patients, but it is still unknown whether inflammation and ADMA interact in the high risk of death and CV events in this population.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

In a cohort of 225 hemodialysis patients, we investigated the interaction between inflammatory biomarkers (C-reactive protein and IL-6) and ADMA as predictors of death and CV events over an extended follow-up (13 years).

RESULTS

During follow-up, 160 patients died, and 123 had CV events. With crude and multiple Cox regression analyses, an interaction was found between inflammation biomarkers and ADMA for explaining death and CV events in ESRD patients. The adjusted hazard ratios (HRs) for death (HR, 2.18; 95% confidence interval [CI], 1.34 to 3.54) and CV outcomes (HR, 2.59; 95% CI, 1.47 to 4.55) of patients with C-reactive protein and ADMA above the median were higher than expected in the absence of interaction under the additive model (1.15 and 1.97, respectively) and significantly higher than in patients with only one biomarker above the median. Data analyses carried out by stratifying patients according to IL-6 provided similar results.

CONCLUSIONS

These data support the hypothesis that inflammation amplifies the risk of death and CV events associated with high ADMA levels in ESRD. These analyses further emphasize the need for intervention studies to attenuate inflammation and high ADMA levels in this population.

Asymmetric dimethylarginine as a mediator of vascular dysfunction and a marker of cardiovascular disease and mortality: an intriguing interaction with diabetes mellitus

Asymmetric dimethylarginine (ADMA) has evolved as an important regulator of nitric oxide (NO) synthesis in recent years. Elevated levels of ADMA have been reported in many conditions associated with a high cardiovascular risk. Moreover, ADMA is a biomarker for major cardiovascular events and mortality in cohorts with high, intermediate and low overall cardiovascular risk. Discrepant data have been reported on cardiovascular risk in people with and without diabetes mellitus, and the association of ADMA with diabetes mellitus per se has also remained controversial, possibly relating to type and stage of diabetes. Clinical and experimental data suggest that there is a multifaceted link between ADMA and insulin metabolism and action on one hand, and ADMA and glucose utilisation on the other. This interplay may be regulated by the enzyme involved in the metabolic degradation of ADMA, dimethylarginine dimethylaminohydrolase (DDAH). Recent data from prospective clinical studies suggest that whilst ADMA may be a marker for total mortality in patients without diabetes, elevated ADMA may exert beneficial effects in patients with diabetes. In this respect, ADMA could serve as a re-coupling agent overcoming endothelial nitric oxide synthase (eNOS) uncoupling in patients with diabetes. Anticipated advances in clinical and experimental investigation will help us to better understand this complex interrelationship between diabetes, eNOS, DDAH and ADMA.

ADMA, C-reactive protein, and albuminuria in untreated essential hypertension: a cross-sectional study

BACKGROUND

Asymmetric dimethylarginine (ADMA) and subclinical inflammation are associated with atherosclerosis progression, whereas microalbuminuria is an established index of hypertensive organ damage.

STUDY DESIGN

Cross-sectional.

SETTING & PARTICIPANTS

In an outpatient hypertensive unit, 296 nondiabetic and untreated participants with hypertension were studied. Participants with atherosclerotic cardiovascular disease, severe valvulopathy, congestive heart failure, presence of neoplastic or other concurrent systemic disease, atrial fibrillation, serum creatinine level > 1.5 mg/dL in men and > 1.4 mg/dL in women, and urinary albumin excretion > 300 mg/24 h were excluded.

PREDICTORS

ADMA and high-sensitivity C-reactive protein (hs-CRP) levels.

OUTCOME VARIABLE

Albuminuria assessed using albumin-creatinine ratio (ACR).

MEASUREMENTS

Participants underwent ambulatory blood pressure monitoring, echocardiography, routine assessment of metabolic profile, ADMA, and hs-CRP, whereas ACR was determined as the mean of 3 values in nonconsecutive morning spot urine samples.

RESULTS

64 participants had an ACR of 30-300 mg/g. Stratification based on ADMA level showed that participants with hypertension in quartile [Q] 4 compared with those in Q3, Q2, and Q1 showed the highest ACRs (53.2 vs 31.2 vs 30.4 vs 16.7 mg/g; P < 0.008 for all). Moreover, stratification based on hs-CRP level showed that participants with hypertension in Q4 (69.8% had microalbuminuria) showed the highest ACRs (72.2 vs 25.6, 16.2, and 19.2 mg/g for Q3, Q2, and Q1, respectively; P < 0.008 for all). Stepwise regression analysis showed that age, 24-hour systolic blood pressure, hs-CRP level, ADMA level, and the interaction of hs-CRP with ADMA were independent predictors of ACR (R(2) = 0.674; P < 0.001).

LIMITATIONS

Cross-sectional study.

CONCLUSIONS

In patients with untreated essential hypertension, increased hs-CRP and ADMA levels are associated with microalbuminuria, suggesting the involvement of inflammation and endothelial dysfunction in vascular and kidney damage.

Circulating asymmetric dimethylarginine, endothelin-1 and cell adhesion molecules in women with gestational diabetes

We measured plasma concentrations of asymmetric dimethylarginine (ADMA), endothelin-1 (ET-1), soluble vascular cell adhesion molecule-1 (sVCAM-1) and E-selectin in 56 patients with gestational diabetes (GDM), 68 pregnant women with normal glucose tolerance (NGT) and 36 healthy non-pregnant women. ADMA concentrations were markedly lower in NGT [0.48 (0.42-0.55) micromol/l] than in GDM subjects [0.50 (0.43-0.67) micromol/l] and healthy controls [0.57 (0.46-0.72) micromol/l, P = 0.005]. ET-1 levels were comparable between GDM [0.76 (0.58-0.90) pg/ml] and NGT women [0.75 (0.63-0.92) pg/ml] and significantly higher than in the non-pregnant subjects [0.62 (0.52-0.72) pg/ml, P = 0.007 and P = 0.005, respectively]. There were no differences in sVCAM-1 and E-selectin levels between the groups studied. ADMA levels were significantly associated with fasting glucose (beta = 0.23, P = 0.02) and gestational age (beta = 0.24, P = 0.01). Our results suggest that physiological adaptation to pregnancy is associated with a fall in circulating ADMA and an elevation of ET-1 concentrations, irrespective of the disturbances of glucose tolerance.

Asymmetric dimethylarginine association with antioxidants intake in healthy young adults: a role as an indicator of metabolic syndrome features

The purpose of this study was to evaluate the potential associations between serum asymmetric dimethylarginine (ADMA) and several anthropometric, biochemical, and lifestyle features in healthy young adults, emphasizing on the putative effects of the antioxidant intake on ADMA concentrations. Anthropometric and blood pressure measurements as well as lifestyle features and antioxidant intake were analyzed in 93 healthy young adults aged 18 to 34 years. Fasting blood samples were collected for the measurement of glucose, total cholesterol, high-density lipoprotein cholesterol, low-density lipoprotein cholesterol, triacylglycerols, and ADMA concentrations, as well as erythrocyte glutathione peroxidase activity. Nail samples were collected for the analysis of selenium and zinc concentrations. Values of body mass index (P = .004), waist circumference (P = .008), waist-to-height ratio (P = .046), systolic blood pressure (P < .001), serum glucose (P < .001), and nail selenium (P = .004) and zinc (P = .018) were significantly different between subjects with serum ADMA higher and lower than the median (cutoff, 458 nmol/L). Furthermore, ADMA showed a positive association with several adiposity markers such as body weight (P < .001), body mass index (P < .001), waist circumference (P = .006), waist-to-height ratio (P = .020), body fat mass (P = .001), systolic blood pressure (P = .001), and serum glucose (P < .001), whereas erythrocyte glutathione peroxidase activity (P = .021) and nail selenium (P = .040) and zinc values (P = .013) were statistically significant negative predictors of ADMA concentrations. In conclusion, ADMA seems to be related with selenium and zinc status and several anthropometric and biochemical measurements linked to metabolic syndrome in apparently healthy young adults. These findings support a role for antioxidant/trace element intake in the modulation of ADMA, whose assessment may be a marker of metabolic syndrome manifestations.

Dimethylarginine dimethylaminohydrolase regulation: a novel therapeutic target in cardiovascular disease

Asymmetric dimethylarginine (ADMA), an endogenous methylated form of the amino acid L-arginine, inhibits the activity of the enzyme endothelial nitric oxide synthase, with consequent reduced synthesis of nitric oxide. ADMA is metabolised to L-citrulline and dimethylamine by the enzyme dimethylarginine dimethylaminohydrolase (DDAH). The modulation of DDAH activity and expression plays a pivotal role in regulating intracellular ADMA concentrations, with important effects on vascular homeostasis. For example, impairment in DDAH activity, resulting in elevated ADMA concentrations and reduced nitric oxide synthesis, can promote the onset and progression of atherosclerosis in experimental models. This review discusses the current role of ADMA and DDAH in vascular health and disease, the techniques used to assess DDAH activity and expression, and the results of recent studies on pharmacological and biological agents modulating DDAH activity and expression. Suggestions for future basic and clinical research directions are also discussed.

Asymmetric dimethylarginine in hematological malignancies: a preliminary study

Asymmetric dimethylarginine (ADMA) is a product of protein hydrolysis and an endogenous competitive inhibitor of nitric oxide synthase. It is considered a new independent risk factor for endothelial dysfunction and cardiovascular diseases. Increased protein turnover, oxidative stress and impaired dimethylarginine dimethylaminohydrolase activity occurring in hematological malignancies may lead to increased dimethylarginines production. We have measured ADMA, symmetric dimethylarginine (SDMA) and L-arginine plasma levels in 43 patients with different types of hematological malignancies and in control group of 43 healthy volunteers. Mean ADMA and L-arginine plasma levels were higher in hematological group than in control group (1.59 vs 0.64; p<0.001 and 34.84 vs 28.35; p=0.044 respectively). Mean plasma levels of SDMA were not significantly different between the groups. Elevated ADMA plasma levels in patients with hematological malignancies interfere with nitric oxide metabolism and may influence their prognosis. Further prognostic studies are postulated to assess this phenomenon.

The hexosamine biosynthesis inhibitor azaserine prevents endothelial inflammation and dysfunction under hyperglycemic condition through antioxidant effects

Hexosamine biosynthetic pathway (HBP) accounts for some cardiovascular adverse effects of hyperglycemia. We investigated whether the HBP inhibitor azaserine protects against hyperglycemia-induced endothelial damage dependently of HBP. Human endothelial cells isolated from umbilical veins were exposed either to a high (30.5 mmol/l) or low concentration of glucose (5.5 mmol/l) for 4 days, followed by a stimulation with TNF-alpha (1 ng/ml, 24 h). The blockade of the rate-limiting enzyme glutamine:fructose-6-phosphate amidotransferase inhibited HBP flux and oxidative stress (generation of superoxide and peroxynitrite) under the hyperglycemic condition and prevented the synergistic stimulation of VCAM-1 and ICAM-1 expression by hyperglycemia and TNF-alpha. In the cells cultured under a low-glucose condition when no increased HBP flux occurred, azaserine enhanced the manganese-superoxide dismutase (MnSOD) protein level and also inhibited the oxidative stress and the expression of VCAM-1 and ICAM-1 in response to TNF-alpha. Moreover, the polyphenol resveratrol inhibited the oxidative stress and adhesion molecule expression and did not decrease the HBP flux under the hyperglycemia condition. In addition, in isolated rat aortas exposed to hyperglycemic buffer for 5 h when no significant HBP flux occurred, azaserine upregulated the MnSOD protein level and prevented decreased endothelium-dependent relaxations to acetylcholine. In conclusion, hyperglycemia independently increases oxidative stress and HBP flux, amplifies endothelial inflammation, and impairs endothelial function mainly through oxidative stress and not the HBP pathway. Azaserine protects against hyperglycemic endothelial damage through its antioxidant effect independently of inhibiting HBP pathway.