Effects Of Asymmetric Dimethylarginine Research Articles

Effects of rosuvastatin on serum asymmetric dimethylarginine levels and incidence of long-term cardiovascular events in patients with hyperlipidaemia and H-type hypertension.

Aims/Background Rosuvastatin is a common lipid-lowering statin on the market, but its impact on the incidence of long-term cardiovascular events is not well clarified. This study aimed to explore the effects of rosuvastatin on serum asymmetric dimethylarginine (ADMA) levels and the incidence of long-term cardiovascular events in patients with hyperlipidaemia and H-type hypertension. Methods This retrospective study included 158 patients with hyperlipidaemia and H-type hypertension who were treated in the Hebei Cangzhou Hospital of Integrated Traditional Chinese Medicine and Western Medicine from August 2015 to August 2016. The patients were divided into an occurrence group and a non-occurrence group according to the occurrence of long-term cardiovascular events following the resuvostatin treatment. The changes in blood lipids, blood pressure, serum ADMA levels and vascular endothelial function indexes before and after treatment were compared, and the effect of ADMA on the occurrence of long-term cardiovascular events and its predictive efficacy were analysed using the Spearman correlation test and receiver operating characteristics (ROC) curve. Results After treatment, the levels of serum total cholesterol, low-density lipoprotein cholesterol, triglyceride, serum ADMA and blood pressure became significantly lower (p < 0.001), with high-density lipoprotein cholesterol exhibiting no significant difference. Twenty-two cases developed long-term cardiovascular events after the treatment, with an incidence of 13.92%. The occurrence group had significantly higher serum ADMA levels than the non-occurrence group (p < 0.001). The rosuvastatin treatment also lowered the levels of endothelin-1 and high-sensitivity C-reactive protein and increased the nitric oxide level (p < 0.001). Spearman correlation analysis showed that serum ADMA levels were positively correlated with the occurrence of long-term cardiovascular events (r=0.462, p < 0.001). Meanwhile, according to the ROC curve, serum ADMA had a good predictive efficacy for long-term cardiovascular events, with an area under the curve of 0.885 (95% confidence interval 0.808-0.963; p < 0.001). Conclusion Rosuvastatin can reduce ADMA levels and exert vascular protective effects. The increase in serum ADMA levels is closely related to the occurrence of long-term cardiovascular events in patients with hyperlipidaemia and H-type hypertension, serving as a potential clinical predictor to guide disease prevention and treatment.

The Study of Serum Asymmetric Dimethylarginine Concentrations in the Different Paraoxonase Phenotypes of Exudative Age-related Macular Degeneration Disease

Background and Aims: Age-related macular degeneration (ARMD) is a degenerative retinal disorder that causes progressive loss of central vision in older adults. The study aimed to determine the effect of asymmetric dimethylarginine (ADMA) as oxidizing metabolite and paraoxonase (PON1) activity within its phenotypes as an antioxidant agent in the development of such multifactorial disease. Materials and methods: Forty-five exudative ARMD (E-ARMD) patients and 45 healthy controls were enrolled for this case-control study. Serum PON1 activity was measured using paraoxon and phenylacetate as substrates. PON1 phenotype was determined using the double-substrate method. The ADMA and oxidized LDL (OX-LDL) levels were determined by enzyme-linked immunosorbent assay method. Blood lipid profile was measured, and nontraditional lipid indexes were calculated. Results: Three phenotypes were determined for PON1 among the participants in the study, including AA, AB, and BB phenotypes with low, moderate, and high activity, respectively. AA phenotype was more frequent among E-ARMD, while AB and BB phenotypes were more common among healthy subjects. The mean ADMA and OX-LDL levels were significantly higher in the patients comparing to the controls (p=0.02 and p=0.01, respectively). No significant differences were found in ADMA and OX-LDL levels between phenotypes in each group and also among similar phenotypes. LDL, cholesterol, and even all comprehensive lipid indexes except (atherogenic index of plasma) were higher in E-ARMD patients compared with the healthy group. Conclusions: It was concluded that high-risk individuals could be identified by evaluating the blood factors involved in oxidative stress, and antioxidant therapies may reduce the incidence and progression of the disease.

Nebivolol ameliorates asymmetric dimethylarginine-induced vascular response in rat aorta via β3 adrenoceptor-mediated mechanism

Background: Asymmetric dimethylarginine (ADMA), an endogenous nitric oxide synthase (NOS) inhibitor, induces endothelial dysfunction. Nebivolol, a highly selective β1-adrenergic receptor (AR) blocker, is the only beta-blocker known to induce vascular production of nitric oxide. Objective: The present study was designed to evaluate the effect and mechanism of nebivolol on ADMA-induced vascular response in rat aorta in vitro. Methods: In vitro, the effects of nebivolol and ADMA on resting tone or contraction induced by phenylephrine (PE, 10−6 mol/L) and relaxation induced by acetylcholine (Ach, 10−10–10−5 mol/L) were evaluated. Results: ADMA in a concentration-dependent manner increased the resting and PE-induced tone and reduced Ach-induced relaxation. Nebivolol inhibited the ADMA-induced enhancements in tone and reversed the effects of ADMA on Ach-induced relaxation. These effects of nebivolol were blocked by selective β3 receptor blocker cyanopindolol (1 μM), but not by selective β2 receptor blocker butoxamine (50 μM). Conclusions: Nebivolol ameliorates the ADMA-induced vascular responses in rat aorta, at least in part, by mechanisms involving β3 adrenoceptor.

Asymmetric dimethyl arginine induces pulmonary vascular dysfunction via activation of signal transducer and activator of transcription 3 and stabilization of hypoxia-inducible factor 1-alpha

Pulmonary hypertension (PH), associated with imbalance in vasoactive mediators and massive remodeling of pulmonary vasculature, represents a serious health complication. Despite the progress in treatment, PH patients typically have poor prognoses with severely affected quality of life. Asymmetric dimethyl arginine (ADMA), endogenous inhibitor of endothelial nitric oxide synthase (eNOS), also represents one of the critical regulators of pulmonary vascular functions. The present study describes a novel mechanism of ADMA-induced dysfunction in human pulmonary endothelial and smooth muscle cells. The effect of ADMA was compared with well-established model of hypoxia-induced pulmonary vascular dysfunction. It was discovered for the first time that ADMA induced the activation of signal transducer and activator of transcription 3 (STAT3) and stabilization of hypoxia inducible factor 1α (HIF-1α) in both types of cells, associated with drastic alternations in normal cellular functions (e.g., nitric oxide production, cell proliferation/Ca2+ concentration, production of pro-inflammatory mediators, and expression of eNOS, DDAH1, and ICAM-1). Additionally, ADMA significantly enhanced the hypoxia-mediated increase in the signaling cascades. In summary, increased ADMA may lead to manifestation of PH phenotype in human endothelial and smooth muscle cells via the STAT3/HIF-1α cascade. Therefore this signaling pathway represents the potential pathway for future clinical interventions in PH.

Exogenous Asymmetric Dimethylarginine (ADMA) in Pathogenesis of Ischemia-Reperfusion-Induced Gastric Lesions: Interaction with Protective Nitric Oxide (NO) and Calcitonin Gene-Related Peptide (CGRP)

Asymmetric dimethylarginine (ADMA) is an endogenous nitric oxide (NO) synthesis inhibitor and pro-inflammatory factor. We investigated the role of ADMA in rat gastric mucosa compromised through 30 min of gastric ischemia (I) and 3 h of reperfusion (R). These I/R animals were pretreated with ADMA with or without the combination of l-arginine, calcitonin gene-related peptide (CGRP) or a small dose of capsaicin, all of which are known to afford protection against gastric lesions, or with a farnesoid X receptor (FXR) agonist, GW 4064, to increase the metabolism of ADMA. In the second series, ADMA was administered to capsaicin-denervated rats. The area of gastric damage was measured with planimetry, gastric blood flow (GBF) was determined by H2-gas clearance, and plasma ADMA and CGRP levels were determined using ELISA and RIA. ADMA significantly increased I/R-induced gastric injury while significantly decreasing GBF, the luminal NO content, and the plasma level of CGRP. This effect of ADMA was significantly attenuated by pretreatment with CGRP, l-arginine, capsaicin, or a PGE2 analogue. In GW4064 pretreated animals, the I/R injury was significantly reduced and this effect was abolished by co-treatment with ADMA. I/R damage potentiated by ADMA was exacerbated in capsaicin-denervated animals with a further reduction of CGRP. Plasma levels of IL-10 were significantly decreased while malonylodialdehyde (MDA) and plasma TNF-α contents were significantly increased by ADMA. In conclusion, ADMA aggravates I/R-induced gastric lesions due to a decrease of GBF, which is mediated by a fall in NO and CGRP release, and the enhancement of lipid peroxidation and its pro-inflammatory properties.

Role of asymmetric methylarginine and connexin 43 in the regulation of pulmonary endothelial function.

Abstract Circulating levels of asymmetric dimethylarginine (ADMA), a nitric oxide synthase inhibitor, are increased in patients with idiopathic pulmonary hypertension (IPAH). We hypothesized that ADMA abrogates gap junctional communication, required for the coordinated regulation of endothelial barrier function and angiogenesis, and so contributes to pulmonary endothelial dysfunction. The effects of ADMA on expression and function of gap junctional proteins were studied in human pulmonary artery endothelial cells; pulmonary endothelial microvascular cells from mice deficient in an enzyme metabolizing ADMA, dimethylarginine dimethylaminohydrolase I (DDAHI); and blood-derived endothelial-like cells from patients with IPAH. Exogenous and endogenous ADMA inhibited protein expression and membrane localization of connexin 43 (Cx43) in a nitric oxide/soluble guanosine monophosphate/c-jun-dependent manner in pulmonary endothelial cells, resulting in the inhibition of gap junctional communication, increased permeability, and decreased angiogenesis. The effects of ADMA were prevented by overexpression of DDAHI or Cx43 and by treatment with rotigaptide. Blood-derived endothelial-like cells from IPAH patients displayed a distinct disease-related phenotype compared to cells from healthy controls, characterized by reduced DDAHI expression, increased ADMA production, and abnormal angiogenesis. In summary, we show that ADMA induces pulmonary endothelial dysfunction via changes in expression and activity of Cx43. Cells from IPAH patients exhibit abnormal DDAHI/Cx43 signaling as well as differences in gap junctional communication, barrier function, and angiogenesis. Strategies that promote DDAHI/Cx43 signaling may have an endothelium-protective effect and be beneficial in pulmonary vascular disease.

Comparison of maternal serum and umbilical cord concentrations of nitric oxide and asymmetric-dimethyl-arginine in pre-eclamptic and uncomplicated pregnancies

The aim of this study was to compare maternal serum and umbilical cord levels of asymmetric-dimethyl-arginine (ADMA) and nitric oxide (NO) in pre-eclamptic and non-pre-eclamptic women and the possible effects of ADMA and NO on fetal outcome. Mean umbilical cord and maternal serum NO and ADMA levels of 29 women with preeclampsia (PE) and 24 randomly selected healthy pregnant women were compared. Maternal venous blood samples were collected before delivery and umbilical cord venous blood samples were obtained after delivery. Birth weight, apgar score, cord blood pH, duration of stay in the neonatal intensive care unit (NICU), and maternal and neonatal complications were recorded. Umbilical cord ADMA and maternal NO levels were significantly higher in women with pre-eclampsia compared to women without pre-eclampsia. There were no significant differences between means of maternal serum ADMA levels and cord blood NO levels in women with and without pre-eclampsia. Maternal and cord serum NO and ADMA levels in the pre-eclampsia group did not show a significant correlation with cord blood pH, umbilical artery pulsatility index (PI). In conclusion, umbilical cord ADMA and maternal NO levels were significantly higher in women with pre-eclampsia compared to women without pre-eclampsia.

Effects of asymmetric dimethylarginine on inflammatory cytokines (TNF-α, IL-6 and IL-10) in rats

This study is intended to examine the effects of administration of asymmetric dimethylarginine (ADMA) on the levels of tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6) and IL-10. A total of 30 Wistar adult albino rats were used. Group I was administrated (n=10) with 1mg/kg/day of ADMA, group II (n=10) was administrated with 2mg/kg/day of ADMA and the control group was administrated (n=10) with 0.9% sodium chloride. ADMA was intraperitoneally administrated for 7days. The serum levels of IL-6, TNF-α and IL-10 were measured. There was a significant decrease in the levels of TNF-α, IL-6 and IL-10 in group I compared with that of the control group (p<0.001). There was also a significant decrease in the levels of IL-10 in group II compared with that of the control group (p<0.05) but the increase was much more distinct in the levels of IL-6 and TNF-α (p<0.001). When comparing the groups by the doses given, no difference between the levels of IL-6 and IL-10 in groups I and II (p>0.05) was observed; the levels of TNF-α in group II were significantly lower than those of group I (p<0.05). A significant decrease in the serum levels of inflammatory cytokines IL-6, TNF-α and IL-10, after administration of 1mg/kg/day and 2mg/kg/day of ADMA, indicates that ADMA has an effect on inflammation. Increase in ADMA levels in the rats shows that the effects of inflammatory cytokines were suppressed.

Abstract 18601: The Role of ADMA Metabolism in the Regulation of Human Pulmonary Endothelial Cell Function

Objective: Asymmetric dimethylarginine (ADMA), a nitric oxide synthase inhibitor, is increased in patients with idiopathic pulmonary hypertension (IPAH). We hypothesized that ADMA abrogates gap junctional communication required for the coordinated regulation of pulmonary endothelial permeability and angiogenesis, contributing to the disease. Methods and Results. The effects of ADMA on expression and function of gap junctional proteins were studied in human pulmonary artery endothelial cells (HPAECs). ADMA inhibited protein expression and cell surface localization of connexin 43 (Cx43) in HPAECs (2-fold decrease, P&lt;0.01), resulting in impaired gap junctional communication, as shown by Fluorescence Recovery After Photobleaching (FRAP). ADMA regulated Cx43 expression and function via the nitric oxide signalling pathway, as effects could be reversed by the nitric oxide donor SNAP, and nitric oxide secondary messengers, cAMP and cGMP. Defective gap junction communication in HPAECs led to endothelial dysfunction, including increased trans-endothelial permeability (1.7-fold increase, P&lt;0.001), and impaired angiogenesis(1.7-fold decrease, P&lt;0.001). The effects of ADMA were prevented by over expressing dimethylarginine dimethylaminohydrolase I (DDAHI), an enzyme that metabolised ADMA, or treatment with the Cx43-gap junction activating drug, rotigaptide.Reduced Cx43 expression was also found in lungs of mice deficient in DDAHI. In vivo lung permeability was increased in DDAHI homozygous knockout mice (1.2-fold increase, P&lt;0.05), and was alleviated by application of rotigaptide. Endothelial colony forming cells from IPAH patients showed reduced expression of DDAHI and Cx43 (2-fold decrease, P&lt;0.05), resulting in impaired endothelial barrier function and abnormal angiogenesis. Conclusions. ADMA is critical in the regulation of gap junctional communication in pulmonary endothelium. Endothelial cells from IPAH patients show reduced ADMA metabolism resulting in defective gap junctional communication and abnormal angiogenic responses. Enhancing Cx43 function may have endothelium-protective effects in conditions associated with reduced nitric oxide signalling, such as pulmonary hypertension.

The mechanism of long-term low-dose asymmetric dimethylarginine inducing transforming growth factor-β expression in endothelial cells

Asymmetric dimethylarginine (ADMA), an endogenous nitric oxide synthase (NOS) inhibitor, accumulates in plasma during chronic kidney disease (CKD). High plasma levels of ADMA can increase transforming growth factor-β (TGF-β) expression, related to renal fibrosis, but the precise molecular mechanism is not explicit. The present study was designed to determine the mechanism through which long-term low-dose ADMA induces TGF-β expression in endothelial cells and to investigate the molecular mechanism of its action. Human umbilical vein endothelial cells (HUVECs) were exposed to low-dose ADMA (5 and 10µmol/l) for 7passages and TGF-β expression was determined. Human renal glomerular endothelial cells (HRGECs) were exposed to high-dose ADMA (100µmol/l) which were used to clarify the molecular mechanism. The results showed that long-term low-dose ADMA (5 and 10µmol/l) increases TGF-β production in both mRNA and protein levels in HUVECs in a time-dependent manner. We confirmed that exogenous ADMA (100µmol/l) significantly enhanced stress fiber formation in HRGECs and upregulated TGF-β expression. Such effects of ADMA in HRGECs were inhibited by pre-treatment with actin depolymerizing agent, actin stabilizing agent, p38 MAPK inhibitor and NADPH oxidase inhibitor. In addition, we demonstrated that ADMA (100µmol/l) significantly activated nuclear factor-κB (NF-κB) in HRGECs, which was markedly attenuated by actin depolymerizing agent, actin stabilizing agent, p38 MAPK inhibitor and NADPH oxidase inhibitor. In brief, the present study demonstrated that long-term low-dose ADMA induces TGF-β expression in endothelial cells at both the gene and protein levels. The actin cytoskeleton may be involved in modulation of ADMA-induced NF-κB activation and the ensuing TGF-β expression in HRGECs.

Inhibition of CaMKII/ERK-Mediated eNOS Phosphorylation Impairs Endothelial Function in Renal Failure Mice: New Effect of AsymmetricDimethylarginine

Inhibition of CaMKII/ERK-Mediated eNOS Phosphorylation Impairs Endothelial Function in Renal Failure Mice: New Effect of AsymmetricDimethylarginine

Inhibition of eNOS phosphorylation mediates endothelial dysfunction in renal failure: new effect of asymmetric dimethylarginine

Patients with chronic kidney disease have elevated circulating asymmetric dimethylarginine (ADMA). Recent studies have suggested that ADMA impairs endothelial nitric oxide synthase (eNOS) by effects other than competition with the substrate L-arginine. Here, we sought to identify the molecular mechanism by which increased ADMA causes endothelial dysfunction in a chronic kidney disease model. In wild-type mice with remnant kidney disease, blood urea nitrogen, serum creatinine, and ADMA were increased by 2.5-, 2-, and 1.2-fold, respectively, without any change in blood pressure. Nephrectomy reduced endothelium-dependent relaxation and eNOS phosphorylation at Ser1177 in isolated aortic rings. In transgenic mice overexpressing dimethylarginine dimethylaminohydrolase-1, the enzyme that metabolizes ADMA, circulating ADMA was not increased by nephrectomy and was decreased to half that of wild-type mice. These mice did not exhibit the nephrectomy-induced inhibition of both endothelium-dependent relaxation and eNOS phosphorylation. In cultured human endothelial cells, agonist-induced eNOS phosphorylation and nitric oxide production were decreased by ADMA at concentrations less than that of L-arginine in the media. Thus, elevated circulating ADMA may be a cause, not an epiphenomenon, of endothelial dysfunction in chronic kidney disease. This effect may be attributable to inhibition of eNOS phosphorylation.

To study the effect of asymmetric dimethylarginine on nitric oxide synthase activity isolated from sheep kidney

To study the effect of asymmetric dimethylarginine on nitric oxide synthase activity isolated from sheep kidney

Contribution of Endogenous Inhibitor of Nitric Oxide Synthase to Hepatic Mitochondrial Dysfunction in Streptozotocin-induced Diabetic Rats

Aims: Mitochondrial dysfunction plays important roles in the development of diabetes. Elevated nitric oxide (NO) synthase inhibitor asymmetric dimethylarginine (ADMA) has been shown to be closely related to diabetes. But the relationship between them in diabetes has not been determined. This study was to explore the role of ADMA in hepatic mitochondrial dysfunction and its potential mechanisms in diabetic rats and hepatocytes. Methods: Respiratory enzymes activities, mitochondrial transmembrane potential and ATP content were measured to evaluate mitochondrial function. The copy number ratio of mitochondrial gene to nuclear gene was used to represent mitochondrial biogenesis. The activity of superoxide dismutase and malondialdehyde content were detected to reflect oxidative stress. Furthermore, changes in ADMA and NO contents, uncoupling protein 2 (UCP2) and peroxisome proliferator-activated receptor-γ coactivator 1α (PGC-1α) transcriptions were determined. Results: Elevated ADMA levels in serum of diabetic rats were found to be associated with hepatic mitochondrial dysfunction reflected by reductions of respiratory enzyme activities, mitochondrial membrane potential and ATP contents. Similar mitochondrial dysfunction also occurred in ADMA-treated hepatocytes. The mitochondrial dysfunction observed in diabetic rats or hepatocytes was accompanied with suppressions of mitochondrial biogenesis, PGC-1α transcription and NO synthesis as well as enhances of UCP 2 transcription and oxidative stress. These effects of ADMA could be attenuated by treatments with antioxidant or NO donor. Conclusions: These results indicate that elevated endogenous ADMA contributes to hepatic mitochondrial dysfunction in diabetic rats, and underlying mechanisms may be related to the suppression of mitochondrial biogenesis and mitochondrial uncoupling via inhibiting NO synthesis and enhancing oxidative stress.

Involvement of asymmetric dimethylarginine and Rho kinase in the vascular remodeling in monocrotaline-induced pulmonary hypertension

Recent studies have shown that the plasma level of asymmetric dimethylarginine (ADMA) was increased accompanied by the decreased dimethylarginine dimethylaminohydrolase (DDAH) activity in pulmonary hypertension (PH) and ADMA was able to regulate pulmonary endothelial cells mobility through increasing the activity of Rho kinase (ROCK). This work was conducted to explore the role of ADMA/DDAH pathway in vascular remodeling in PH and the underlying mechanisms. The rat model of PH was established by a single injection of monocrotaline (60 mg/kg, s.c.). The pulmonary arterial pressure, the remodeling of pulmonary artery, the hypertrophy of right ventricle, the plasma levels of ADMA and NO, the expression of DDAH2, ROCK1 or ROCK2 and the ROCK activity were determined. In vitro studies, the pulmonary artery smooth muscle cells (PASMCs) were isolated and cultured. The effect of ADMA on PASMCs proliferation and ROCK activation was investigated. The results showed that the injection of monocrotaline successfully induced PH characterized by the increased pulmonary arterial pressure, vascular remodeling and right ventricle hypertrophy. The plasma level of ADMA was elevated concomitantly with the increased ROCK activity and ROCK1 expression as well as the decreased DDAH2 expression in pulmonary arteries. In the cultured PASMCs, ADMA promoted cellular proliferation accompanied by the increased ROCK1 expression and ROCK activity, which was attenuated by the ROCK inhibitor or by the intracellular antioxidant. These results suggest that ADMA could promote the proliferation of PASMCs through activating ROCK pathway, which may account for, at least partially, the vascular remodeling in monocrotaline-induced PH.

A novel predictor of restenosis and adverse cardiac events: asymmetric dimethylarginine

The aim of this study is to investigate if serum asymmetric dimethylarginine (ADMA) levels can predict restenosis and major adverse cardiac events (MACE) in patients who undergo percutaneous coronary interventions. The most important cause of restenosis following percutaneous coronary intervention is neointimal hyperplasia. Nitric oxide (NO) prevents the neointimal hyperplasia growing. Asymmetric dimethylarginine is a competitive inhibitor of NO synthesis. The effect of ADMA on the restenosis has not yet been investigated. A total of 105 (80 male and 25 female) patients were included in our study. All patients underwent elective percutaneous transluminal coronary angioplasty (PTCA) with bare metal stent implantation or direct stenting for one coronary artery between September 2004 and January 2006. All patients were clinically followed for a period of 6 months, and a control angiography was performed at the end of this period. The probrain natriuretic peptide (pro-BNP), high-sensitivity Creactive protein (hs-CRP), and ADMA levels of the patients were evaluated before the procedure and 6 months afterwards. Biochemical parameters and angiographic features were evaluated in order to determine if they could predict the development of restenosis and MACE by using univariate and multivariate Cox regression analysis. The 65 (61.9%) patients (50 males and 15 females) who had not developed restenosis were designated as Group 1. The 27 (25.7%) patients (21 males and 6 females) who had developed restenosis were designated as Group 2. In terms of predicting the development of restenosis, the presence of diabetes mellitus (hazard ratio [HR]: 2.78; confidence interval [CI]: 1.25-6.20; P = 0.01), type of lesion (HR: 1.89; CI: 1.01-3.55; P = 0.04), form of procedure (HR: 0.30; CI: 0.11-0.81; P = 0.01), and ADMA (HR: 4.08; CI: 1.73-9.62; P = 0.001) were found to be significant in univariate Cox regression analysis. In contrast, only the levels of ADMA were found to be a significant predictor of restenosis in the multivariate Cox regression analysis (HR: 3.02; CI: 1.16-7.84; P = 0.02). The restenosis prediction of ADMA levels continued after excluding the patients with diabetes mellitus in the univariate and multivariate Cox regression analysis (HR: 5.23; CI: 1.99-13.76; P = 0.001 and HR: 5.61; CI: 1.79-17.62; P = 0.003, respectively). Regarding the development of cardiac events, hs-CRP (HR: 1.03; CI: 1.00-1.06; P = 0.01) and ADMA (HR: 17.1; CI: 3.06-95.8; P = 0.001) were found to be significantly correlated with adverse cardiac events in univariate Cox regression analysis, whereas only ADMA levels were significant in the multivariate Cox regression analysis (HR: 2.83; CI: 1.27-6.31; P = 0.01). The levels of ADMA obtained before the procedure predict the development of restenosis and MACE in patients who underwent elective PTCA and bare metal stent procedures.

Involvement of asymmetric dimethylarginine (ADMA) in glomerular capillary loss and sclerosis in a rat model of chronic kidney disease (CKD)

Aims Asymmetric dimethylarginine (ADMA), an endogenous nitric oxide synthase inhibitor, has been reported to be a novel marker for the progression of chronic kidney disease (CKD). We have recently found that accumulation of ADMA could trigger peritubular capillary loss, thus contributing to tubulointerstitial ischemia and fibrosis in a rat model of CKD. However, effects of ADMA on glomerular capillary loss and sclerosis remain to be elucidated. Main methods In this study, we investigated whether lowering of ADMA by overexpression of dimethylarginine dimethylaminohydrolase (DDAH), a main enzyme that degrades ADMA, could ameliorate glomerular capillary loss and sclerosis in a rat model of CKD. Four weeks after 5/6 subtotal nephrectomy (Nx), animals were given tail vein injections with recombinant adenovirus vector encoding DDAH-I (Adv-DDAH) or control vector expressing bacterial β-galactosidase (Adv-LZ), or orally administered with 20 mg/kg/day of hydralazine (Hyz) which served as a blood pressure control model. Key findings Plasma levels of ADMA were associated with decreased number of glomerular capillaries as well as severity of glomerular sclerosis in Nx-rats. These glomerular changes progressed in Adv-LZ- or Hyz-treated Nx-rats, while they were ameliorated by the treatment with DDAH overexpression. Significance Our present data suggest that ADMA may be involved in glomerular capillary loss and sclerosis, thus contributing to the progression of CKD. Substitution of DDAH protein or enhancement of its activity may become a novel therapeutic strategy for the treatment of CKD.

The effects of asymmetric dimethyl arginine and nitric oxide levels on early prognosis in patients with myocardial infarction

It is unclear whether abnormalities of nitric oxide metabolism are related to hemodynamic dysfunction and mortality in patients with acute myocardial infarction (MI). Decreased nitric oxide (NO x ) and high levels of asymmetric dimethyl arginine (ADMA) are proposed independent risk factors in coronary artery disease. We investigated the relationship of NO x and ADMA levels with early prognosis in patients with MI. 59 patients (9 women and 50 men, aged 32–75) who were hospitalized at Coronary Care Unit and age-matched 20 healthy controls were included in the study. All clinical and laboratory parameters were monitored. Left ventricular systolic function (LVSF) was investigated by echocardiography as a prognostic marker of cardiac function. NO and ADMA levels were measured on the first day of infarction. NO x was measured spectrophotometrically at 430 nm using the Griess reaction with a commercial kit. Plasma ADMA concentrations were determined by competitive ELISA. MI patients had higher plasma ADMA (0,78 ± 0.44 μmol/L) levels than controls (0.45 ± 0.2 μmol/L). NO x levels were 35.6 ± 10.4 μmol/L in MI patients and 32.5 ± 3.7 μmol/L in controls. There was not a correlation between total and LDL-cholesterol, triglyceride, hs-CRP levels, smoking history, presence of hypertension or diabetes, localization and extent of infarction and ADMA and NO x levels. MI patients had higher plasma ADMA levels than controls and there was not any relation with other coronary risk factors such as total and LDL-cholesterol, triglyceride, hs-CRP levels, smoking history, presence of hypertension or diabetes, localization and extent of infarction and ADMA and NO x levels. We also could not find a correlation between ADMA, NO x levels with LVSF and early cardiac events.

Role of symmetric dimethylarginine in vascular damage by increasing ROS via store-operated calcium influx in monocytes

The guanidines asymmetric dimethylarginine (ADMA), a marker of endothelial dysfunction, and its counterpart symmetric dimethylarginine (SDMA), considered inert, are accumulated in chronic kidney disease (CKD). The present study evaluates their effect on monocyte function, since previous data demonstrated leukocyte activation by other guanidino compounds. The effect of ADMA and SDMA on reactive oxygen species (ROS) production in human whole blood at baseline and after N-formyl-methionine-leucine-phenylalanine (fMLP) stimulation was evaluated. By using the fluorescent probe Fluo3-AM, the role of changes in monocytic cytoplasmic calcium ([Ca2+]i) was studied. Thapsigargin, and removal followed by addition of extracellular Ca2+ (Ca2+(ex)), was used to investigate the contribution of store-operated Ca2+-channels (SOCs). SKF96365 was used as a selective inhibitor of the SOCs. A pharmacologic intervention with captopril, known to affect Ca2+ influx, was tested. SDMA enhanced ROS production in fMLP-stimulated monocytes using heparinized blood, and this effect was abolished in EDTA-anticoagulated blood. In the presence of SDMA, an increased Ca2+ entry from the extracellular milieu resulted in an elevated amplitude of the peak [Ca2+]i change triggered by fMLP. None of these effects were seen with ADMA. Depletion of the intracellular stores with thapsigargin in the absence of Ca2+(ex), followed by re-addition of Ca2+(ex) triggered a significantly larger Ca2+ entry after SDMA treatment versus saline. This effect was prevented with SKF96365, as was the SDMA-enhanced oxidative burst after fMLP. Pre-incubation with captopril also reduced the increased ROS production seen with SDMA. SDMA, a uraemic retention solute considered inert, stimulates ROS production of monocytes by acting on Ca2+ entry via SOCs. This pro-inflammatory effect may trigger vascular pathology and may be involved in altering the prevalence of cardiovascular disease in CKD.

Decrease in the synthesis and release of calcitonin gene-related peptide in dorsal root ganglia of spontaneously hypertensive rat: Role of nitric oxide synthase inhibitors

Calcitonin gene-related peptide (CGRP), the major transmitter in capsaicin-sensitive sensory nerves, and asymmetric dimethylarginine (ADMA), an endogenous inhibitor of nitric oxide synthase, participate in the regulation of blood pressure. In the present study, we tested the relationship between CGRP and ADMA in spontaneously hypertensive rats (SHRs). For the in vivo study, SHRs were treated with or without l-arginine for 2 weeks, and Wistar Kyoto (WKY) rats were used as controls. Systolic arterial pressure was measured, and the levels of CGRP, ADMA, and NO were analyzed. For the in vitro study, neural cells from dorsal root ganglia were treated with NO inhibitor or donor. Synthesis and release of CGRP were measured. Compared with WKY rats, serum concentration of ADMA in SHRs increased while CGRP and NO level decreased. Treatment with l-arginine significantly decreased blood pressure, concomitantly with an increase in the level of NO and the synthesis and release of CGRP in SHRs, but it did not affect ADMA levels. In cultured neural cells, ADMA reduced the level of NO and inhibited the synthesis and release of CGRP in a concentration-dependent manner. The effects of ADMA were reversed by l-arginine. Treatment with NOC-18, a donor of NO, increased the release and synthesis of CGRP in neural cells in a concentration-dependent manner. Decreased synthesis and release of CGRP is related to a reduction in NO levels, and corresponds to the increased concentrations of ADMA in spontaneously hypertensive rats.