ADMA and oxidative stress

Association between Nfr2, HO-1, NF-kB Expression, Plasma ADMA, and Oxidative Stress in Metabolic Syndrome

Endothelial dysfunction is one of the major factors in the pathogenesis of metabolic syndrome (MetS), and its molecular mechanisms are not completely understood. The present study aimed to examine the connection between nuclear factor2-related factor2 (Nrf2), nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB), heme oxygenase 1 (HO-1), and plasma asymmetric dimethylarginine (ADMA) and malondialdehyde (MDA) in people with MetS. Participants in the study were as follows: with MetS (n = 30) and without MetS (Control) (n = 14). Expression of Nrf2, NF-kB, and HO-1 was measured in peripheral blood mononuclear cells (PBMCs). Plasma ADMA was determined using the ELISA technique and MDA via the thiobarbituric acid method. Our study showed that mRNA of NF-kB, Nrf2, and HO-1 levels in PBMCs in the MetS group were significantly higher than in the controls by 53%, 130%, and 185% (p < 0.05), respectively. Similarly, elevated levels of MDA (by 78%, p < 0.001) and ADMA (by 18.7%, p < 0.001) were established in the MetS group. Our findings show the importance of transcription factor Nrf2, playing an integral role in the protection of the endothelium, and of NF-κB, a transcription factor mediating the inflammatory response in MetS. Knowledge of complex cellular-molecular mechanisms would allow the use of biomarkers such as Nrf2, NF-kB, HO-1, and ADMA for the assessment of endothelial dysfunction in clinical practice.

Evaluation of Asymmetric Dimethylarginine, Malondialdehyde, and Vitamin Levels of Borderline Personality Disorder Patients With and Without Self-Mutilation

OBJECTIVE

Believing that oxidative stress may be increased in borderline personality disorder (BPD) patients with self-mutilating behaviors (SMB), we aimed to measure serum asymmetric dimethylarginine (ADMA) and malondialdehyde (MDA) levels in these patients.

METHODS

The study included 60 patients diagnosed with BPD and 30 healthy controls. BPD patients were divided into two groups: 30 female patients with SMB and 30 female patients with no-self-mutilating behavior (NSMB). ADMA, MDA, vitamin A, and vitamin E levels were analyzed. Beck Anxiety Inventory (BAI) and Beck Depression Inventory (BDI) were conducted with the participants.

RESULTS

Serum ADMA and MDA levels were higher in SMB and NSMB group compared to control group. Serum vitamin E levels were also lower in the SMB group compared to the control group. Positive correlations were determined between both ADMA and MDA, and between BDI and BAI scores. Also, BAI scores were statistically higher in SMB group compared to NSMB group.

CONCLUSION

It was discovered that levels of ADMA and MDA, which reflected oxidative stress, were elevated in patients with BPD who exhibited SMB. Accordingly, future studies should investigate the role of oxidative stress in a more comprehensive way in terms of the different mechanisms underlying and treatments involved in borderline personality disorder.

Advances and Perspectives in Relation to the Molecular Basis of Diabetic Retinopathy-A Review

Diabetes mellitus (DM) is a growing problem nowadays, and diabetic retinopathy (DR) is its predominant complication. Currently, DR diagnosis primarily relies on fundoscopic examination; however, novel biomarkers may facilitate that process and make it widely available. In this current review, we delve into the intricate roles of various factors and mechanisms in DR development, progression, prediction, and their association with therapeutic approaches linked to the underlying pathogenic pathways. Specifically, we focus on advanced glycation end products, vascular endothelial growth factor (VEGF), asymmetric dimethylarginine, endothelin-1, and the epigenetic regulation mediated by microRNAs (miRNAs) in the context of DR.

Co-supplementation of Vitamin K2 and Selenium Synergistically Improves Metabolic Status and Reduces Cardiovascular Risk Markers in Dyslipidemic Rabbits

This work investigated the impact of vitamin K2 and selenium co-supplementation on metabolic profile and indicators of cardiovascular health in dyslipidemic rabbits. Fifty adult male rabbits were equally allocated into 5 groups: Control group, Dyslipidemic group: received 0.5% cholesterol in diet for 12 weeks, groups 3, 4 and 5 dyslipidemic rabbits daily treated with vitamin K2 (10 mg/kg bw) or/and selenium (1 mg/kg bw) for 8 weeks. Co-supplementation of vitamin K2 and selenium significantly decreased body weight gain and blood pressure elevation in dyslipidemic rabbits compared to un-treated ones. Consuming vitamin K2 plus selenium also markedly lowered serum lipids encompassing cholesterol, triglycerides and LDL and elevated HDL relative to placebo. Additionally, such co-supplementation reduced fasting glucose and insulin, enhancing insulin sensitivity with respect to placebo. Regarding cardiovascular risk markers, dyslipidemic rabbits received vitamin K2 concurrently with selenium displayed lower levels of atherogenic index (LDL/HDL), serum C-reactive protein, heart fatty acid-binding protein and asymmetric dimethylarginine as well as aortic ox-LDL, lipid peroxidation and calcium but higher levels of serum nitric oxide and aortic total antioxidants than un-treated ones. Concomitant administration of vitamin K2 and selenium improved metabolic profile, markers of cardiovascular health and atherosclerosis in dyslipidemic rabbits.

Metabolic reprogramming, oxidative stress, and pulmonary hypertension

Mitochondria are highly dynamic organelles essential for cell metabolism, growth, and function. It is becoming increasingly clear that endothelial cell dysfunction significantly contributes to the pathogenesis and vascular remodeling of various lung diseases, including pulmonary arterial hypertension (PAH), and that mitochondria are at the center of this dysfunction. The more we uncover the role mitochondria play in pulmonary vascular disease, the more apparent it becomes that multiple pathways are involved. To achieve effective treatments, we must understand how these pathways are dysregulated to be able to intervene therapeutically. We know that nitric oxide signaling, glucose metabolism, fatty acid oxidation, and the TCA cycle are abnormal in PAH, along with alterations in the mitochondrial membrane potential, proliferation, and apoptosis. However, these pathways are incompletely characterized in PAH, especially in endothelial cells, highlighting the urgent need for further research. This review summarizes what is currently known about how mitochondrial metabolism facilitates a metabolic shift in endothelial cells that induces vascular remodeling during PAH.

Pathomechanisms of Prenatally Programmed Adult Diseases

Based on epidemiological observations Barker et al. put forward the hypothesis/concept that an adverse intrauterine environment (involving an insufficient nutrient supply, chronic hypoxia, stress, and toxic substances) is an important risk factor for the development of chronic diseases later in life. The fetus responds to the unfavorable environment with adaptive reactions, which ensure survival in the short run, but at the expense of initiating pathological processes leading to adult diseases. In this review, the major mechanisms (including telomere dysfunction, epigenetic modifications, and cardiovascular-renal-endocrine-metabolic reactions) will be outlined, with a particular emphasis on the role of oxidative stress in the fetal origin of adult diseases.

Significance of Endothelial Dysfunction Amelioration for Sodium-Glucose Cotransporter 2 Inhibitor-Induced Improvements in Heart Failure and Chronic Kidney Disease in Diabetic Patients

Beyond lowering plasma glucose levels, sodium-glucose cotransporter 2 inhibitors (SGLT2is) significantly reduce hospitalization for heart failure (HF) and retard the progression of chronic kidney disease (CKD) in patients with type 2 diabetes. Endothelial dysfunction is not only involved in the development and progression of cardiovascular disease (CVD), but is also associated with the progression of CKD. In patients with type 2 diabetes, hyperglycemia, insulin resistance, hyperinsulinemia and dyslipidemia induce the development of endothelial dysfunction. SGLT2is have been shown to improve endothelial dysfunction, as assessed by flow-mediated vasodilation, in individuals at high risk of CVD. Along with an improvement in endothelial dysfunction, SGLT2is have been shown to improve oxidative stress, inflammation, mitochondrial dysfunction, glucotoxicity, such as the advanced signaling of glycation end products, and nitric oxide bioavailability. The improvements in endothelial dysfunction and such endothelium-derived factors may play an important role in preventing the development of coronary artery disease, coronary microvascular dysfunction and diabetic cardiomyopathy, which cause HF, and play a role in retarding CKD. The suppression of the development of HF and the progression of CKD achieved by SGLT2is might have been largely induced by their capacity to improve vascular endothelial function.

Endothelial dysfunction due to eNOS uncoupling: molecular mechanisms as potential therapeutic targets

Nitric oxide (NO) is one of the most important molecules released by endothelial cells, and its antiatherogenic properties support cardiovascular homeostasis. Diminished NO bioavailability is a common hallmark of endothelial dysfunction underlying the pathogenesis of the cardiovascular disease. Vascular NO is synthesized by endothelial nitric oxide synthase (eNOS) from the substrate L-arginine (L-Arg), with tetrahydrobiopterin (BH₄) as an essential cofactor. Cardiovascular risk factors such as diabetes, dyslipidemia, hypertension, aging, or smoking increase vascular oxidative stress that strongly affects eNOS activity and leads to eNOS uncoupling. Uncoupled eNOS produces superoxide anion (O₂^-) instead of NO, thus becoming a source of harmful free radicals exacerbating the oxidative stress further. eNOS uncoupling is thought to be one of the major underlying causes of endothelial dysfunction observed in the pathogenesis of vascular diseases. Here, we discuss the main mechanisms of eNOS uncoupling, including oxidative depletion of the critical eNOS cofactor BH₄, deficiency of eNOS substrate L-Arg, or accumulation of its analog asymmetrical dimethylarginine (ADMA), and eNOS S-glutathionylation. Moreover, potential therapeutic approaches that prevent eNOS uncoupling by improving cofactor availability, restoration of L-Arg/ADMA ratio, or modulation of eNOS S-glutathionylation are briefly outlined.

New insight of metabolomics in ocular diseases in the context of 3P medicine

Metabolomics refers to the high-through untargeted or targeted screening of metabolites in biofluids, cells, and tissues. Metabolome reflects the functional states of cells and organs of an individual, influenced by genes, RNA, proteins, and environment. Metabolomic analyses help to understand the interaction between metabolism and phenotype and reveal biomarkers for diseases. Advanced ocular diseases can lead to vision loss and blindness, reducing patients' quality of life and aggravating socio-economic burden. Contextually, the transition from reactive medicine to the predictive, preventive, and personalized (PPPM / 3P) medicine is needed. Clinicians and researchers dedicate a lot of efforts to explore effective ways for disease prevention, biomarkers for disease prediction, and personalized treatments, by taking advantages of metabolomics. In this way, metabolomics has great clinical utility in the primary and secondary care. In this review, we summarized much progress achieved by applying metabolomics to ocular diseases and pointed out potential biomarkers and metabolic pathways involved to promote 3P medicine approach in healthcare.

Vascular redox signaling, eNOS uncoupling and endothelial dysfunction in the setting of transportation noise exposure or chronic treatment with organic nitrates

SIGNIFICANCE

Cardiovascular disease and drug-induced health side effects are frequently associated with - or even caused by - an imbalance between the concentrations of reactive oxygen and nitrogen species (RONS) and antioxidants respectively determining the metabolism of these harmful oxidants.

RECENT ADVANCES

According to the "kindling radical" hypothesis, initial formation of RONS may further trigger the additional activation of RONS formation under certain pathological conditions. The present review will specifically focus on a dysfunctional, uncoupled endothelial nitric oxide synthase (eNOS) caused by RONS in the setting of transportation noise exposure or chronic treatment with organic nitrates, especially nitroglycerin. We will further describe the various "redox switches" that are proposed to be involved in the uncoupling process of eNOS.

CRITICAL ISSUES

In particular, the oxidative depletion of tetrahydrobiopterin (BH4), and S-glutathionylation of the eNOS reductase domain will be highlighted as major pathways for eNOS uncoupling upon noise exposure or nitroglycerin treatment. In addition, oxidative disruption of the eNOS dimer, inhibitory phosphorylation of eNOS at threonine or tyrosine residues, redox-triggered accumulation of asymmetric dimethylarginine (ADMA) and L-arginine deficiency will be discussed as alternative mechanisms of eNOS uncoupling.

FUTURE DIRECTIONS

The clinical consequences of eNOS dysfunction due to uncoupling on cardiovascular disease will be summarized also providing a template for future clinical studies on endothelial dysfunction caused by pharmacological or environmental risk factors.

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.

The ADMA-DDAH1 axis in ovarian apoptosis of polycystic ovary syndrome

Dimethylarginine dimethylaminohydrolase 1 (DDAH1) mainly degrades asymmetric dimethylarginine (ADMA), an endogenous nitric oxide synthase inhibitor. Emerging evidence suggested that plasma ADMA is accumulated in patients with polycystic ovary syndrome (PCOS). However, ADMA-DDAH1 involvement in PCOS pathogenesis is unclear. Here, we used dehydroepiandrosterone (DHEA)-induced PCOS rats and the ovarian granulosa cell line KGN to investigate the effect of the ADMA-DDAH1 pathway on ovarian apoptosis. Moreover, we also quantified the ADMA levels and redox status in human serum specimens, Sprague Dawley rats and KGN cells to investigate the effect of ADMA-DDAH1 on redox status and ovarian apoptosis in PCOS. We enrolled 19 women with PCOS and 17 healthy women (controls) in this study. The women with PCOS had increased serum ADMA levels and decreased glutathione peroxidase (GSH-PX) compared with the controls. In Sprague Dawley rats, 21-day DHEA treatment established PCOS and the rat contained higher ADMA levels in serum and lower DDAH1 expression in ovaries. Moreover, the PCOS rat serum and ovaries exhibited increased levels of the oxidative stress marker malondialdehyde (MDA). ADMA treatment of the KGN cells induced reactive oxygen species accumulation and led to apoptosis. Contrastingly, overexpressing DDAH1 in the KGN cells significantly decreased ADMA levels, enhanced cell viability, and inhibited oxidative stress, while the effect was inverse in DDAH1 knockdown cells. Overall, our results demonstrated that PCOS involves elevated ADMA levels and redox imbalance. The ADMA-DDAH1 pathway exerted a marked effect on oxidative stress and ovarian apoptosis in PCOS. Our findings suggested that strategies for increasing DDAH1 activity in ovarian cells may provide a novel approach for ameliorating PCOS.

Correlation of Asymmetric Dimethyl Arginine Level to Sickle Retinopathy in Children With Sickle Cell Disease

Asymmetric dimethyl arginine (ADMA) is a competitive inhibitor of nitric oxide synthetase especially in L-arginine deficiency, which is the case in sickle cell disease (SCD). we aimed to assess the level of ADMA in children with sickle retinopathy and to correlate it to the degree of retinopathy. In this cross-sectional study 40 children with SCD were included, 20 of them with sickle cell retinopathy (SCR) (group I), 20 with normal fundus examination (group II), and another 20 healthy children served as controls (group III). We measured ADMA level by ELISA and performed fundus examination. Seventeen of the 20 children included in group I had Grade I retinopathy (85%), 2 children had Grade II retinopathy (10%), and 1 child had Grade III retinopathy (5%). ADMA was significantly higher in SCD than controls ( P -value <0.001), and it was even higher in patients with SCR compared those without retinopathy ( P -value <0.002), and there was positive linear correlation between ADMA and the grade of retinopathy. The type of retinopathy detect in the studied patients was the nonproliferative type. In conclusion, ADMA is elevated in children with SCD, and its level is even higher in those who develop SCR.

The effect of haptoglobin genotype on the association of asymmetric dimethylarginine and DDAH 1 polymorphism with diabetic macroangiopathy

BACKGROUND

Dimethylarginine dimethylaminohydrolase (DDAH) 1 maintains the bioavailability of nitric oxide by degrading asymmetric dimethylarginine (ADMA). Here, we aimed to investigate the effect of haptoglobin (Hp) genotype on the association of ADMA and DDAH 1 polymorphism with diabetic macroangiopathy.

METHODS

In stage 1, 90 Chinese participants with type 2 diabetes were enrolled to measure a panel of targeted metabolites, including ADMA, using tandem mass spectrometry (BIOCRATES AbsoluteIDQ™ p180 kit). In stage 2, an independent cohort of 2965 Chinese patients with type 2 diabetes was recruited to analyze the effect of Hp genotype on the association between DDAH 1 rs233109 and diabetic macroangiopathy. Hp genotypes were detected using a validated assay based on the TaqMan method. DDAH 1 rs233109 was genotyped by matrix-assisted laser desorption/ionization time-of-flight mass spectroscopy using the MassARRAY platform.

RESULTS

In stage 1, serum ADMA levels correlated with common Hp genotypes (β ± SE = - 0.049 ± 0.023, P = 0.035), but not with diabetic macroangiopathy (P = 0.316). In stage 2, the distribution of DDAH 1 rs233109 genotype frequencies was 15% (CC), 47% (TC), and 38% (TT), which was in Hardy-Weinberg equilibrium (P = 0.948). A significant Hp genotype by rs 233109 genotype interaction effect on diabetic macroangiopathy was found (P = 0.017). After adjusting for confounders, patients homozygous for rs233109 CC were more likely to develop diabetic macroangiopathy than those carrying TT homozygotes in the Hp 2-2 subgroup [odds ratio = 1.750 (95% confidence interval, 1.101-2.783), P = 0.018].

CONCLUSION

Hp genotype affects the association between DDAH 1 rs233109 and diabetic macroangiopathy in Chinese patients with type 2 diabetes.

The Role of L-Arginine-NO System in Female Reproduction: A Narrative Review

Accumulating evidence are available on the involvement of l-arginine-nitric oxide (NO) system in complex biological processes and numerous clinical conditions. Particular attention was made to reveal the association of l-arginine and methylarginines to outcome measures of women undergoing in vitro fertilization (IVF). This review attempts to summarize the expression and function of the essential elements of this system with particular reference to the different stages of female reproduction. A literature search was performed on the PubMed and Google Scholar systems. Publications were selected for evaluation according to the results presented in the Abstract. The regulatory role of NO during the period of folliculogenesis, oocyte maturation, fertilization, embryogenesis, implantation, placentation, pregnancy, and delivery was surveyed. The major aspects of cellular l-arginine uptake via cationic amino acid transporters (CATs), arginine catabolism by nitric oxide synthases (NOSs) to NO and l-citrulline and by arginase to ornithine, and polyamines are presented. The importance of NOS inhibition by methylated arginines and the redox-sensitive elements of the process of NO generation are also shown. The l-arginine-NO system plays a crucial role in all stages of female reproduction. Insufficiently low or excessively high rates of NO generation may have adverse influences on IVF outcome.

Plasma Asymmetrıc Dımethylargınıne (ADMA) and Nıtrıc Oxıde (NO) Levels ın Patıents wıth Chronıc Pansınusıtıs

Chronic pansinusitis is a mucosal inflammation of the nose and all paranasal sinuses with severe inflammation of the upper airways. Asymmetric dimethylarginine (ADMA) is associated with oxidative stress. In this study, we aimed to examine the plasma levels and importance of ADMA and nitric oxide (NO) in patients with chronic pansinusitis. The study was conducted with a total of 64 patients. The study group included a total of 40 patients with chronic pansinusitis. (18 females, 22 males) (mean age 32.27 ± 10.02). The control group consisted of 24 patients (11 females and 13 males). The mean age of the patients in the control group was 31.35 ± 6.05 years. Nasal endoscopic examinations were performed in patients with a history of chronic pansinusitis and symptoms of chronic pansinusitis. Later, the diagnosis of chronic pansinusitis was confirmed with coronal paranasal sinus Computed tomography scans. Plasma ADMA levels were measured by ELISA method and NO levels were measured by Griess method. Plasma ADMA and NO levels of the patients and healthy volunteers were measured and the mean plasma levels of the two groups were compared. ADMA levels were significantly higher in the group with chronic pansinusitis compared to the control group (1.23 ± 0.41 μM and 0.28 ± 0.06 μM, respectively) (p < 0.001), while NO levels were significantly lower in the patient group compared to the control group (7.06 ± 1.07 μM and 12.25 ± 0.95, μM, respectively) (p < 0.001). Our results show that the increase in ADMA levels and the decrease in NO levels are associated with chronic pansinusitis. According to these results, increased plasma levels of ADMA in chronic pansinusitis may be useful in clinical use as a sign of increased oxidative stress.

The Impact of Tobacco Cigarettes, Vaping Products and Tobacco Heating Products on Oxidative Stress

Cells constantly produce oxidizing species because of their metabolic activity, which is counteracted by the continuous production of antioxidant species to maintain the homeostasis of the redox balance. A deviation from the metabolic steady state leads to a condition of oxidative stress. The source of oxidative species can be endogenous or exogenous. A major exogenous source of these species is tobacco smoking. Oxidative damage can be induced in cells by chemical species contained in smoke through the generation of pro-inflammatory compounds and the modulation of intracellular pro-inflammatory pathways, resulting in a pathological condition. Cessation of smoking reduces the morbidity and mortality associated with cigarette use. Next-generation products (NGPs), as alternatives to combustible cigarettes, such as electronic cigarettes (e-cig) and tobacco heating products (THPs), have been proposed as a harm reduction strategy to reduce the deleterious impacts of cigarette smoking. In this review, we examine the impact of tobacco smoke and MRPs on oxidative stress in different pathologies, including respiratory and cardiovascular diseases and tumors. The impact of tobacco cigarette smoke on oxidative stress signaling in human health is well established, whereas the safety profile of MRPs seems to be higher than tobacco cigarettes, but further, well-conceived, studies are needed to better understand the oxidative effects of these products with long-term exposure.

Impact of Zinc on Oxidative Signaling Pathways in the Development of Pulmonary Vasoconstriction Induced by Hypobaric Hypoxia

Hypobaric hypoxia is a condition that occurs at high altitudes (>2500 m) where the partial pressure of gases, particularly oxygen (PO2), decreases. This condition triggers several physiological and molecular responses. One of the principal responses is pulmonary vascular contraction, which seeks to optimize gas exchange under this condition, known as hypoxic pulmonary vasoconstriction (HPV); however, when this physiological response is exacerbated, it contributes to the development of high-altitude pulmonary hypertension (HAPH). Increased levels of zinc (Zn2+) and oxidative stress (known as the “ROS hypothesis”) have been demonstrated in the vasoconstriction process. Therefore, the aim of this review is to determine the relationship between molecular pathways associated with altered Zn2+ levels and oxidative stress in HPV in hypobaric hypoxic conditions. The results indicate an increased level of Zn2+, which is related to increasing mitochondrial ROS (mtROS), alterations in nitric oxide (NO), metallothionein (MT), zinc-regulated, iron-regulated transporter-like protein (ZIP), and nicotinamide adenine dinucleotide phosphate (NADPH) oxidase-induced protein kinase C epsilon (PKCε) activation in the development of HPV. In conclusion, there is an association between elevated Zn2+ levels and oxidative stress in HPV under different models of hypoxia, which contribute to understanding the molecular mechanism involved in HPV to prevent the development of HAPH.

An Optimized MRM-Based Workflow of the l-Arginine/Nitric Oxide Pathway Metabolites Revealed Disease- and Sex-Related Differences in the Cardiovascular Field

Clinical data indicate that low circulating l-homoarginine (HArg) concentrations are associated with cardiovascular (CV) disease, CV mortality, and all-cause mortality. A high number of LC-based analytical methods for the quantification of HArg, in combination with the l-arginine (Arg)-related pathway metabolites, have been reported. However, these methods usually consider a limited panel of analytes. Thus, in order to achieve a comprehensive picture of the Arg metabolism, we described an improved targeted metabolomic approach based on a multiple reaction monitoring (MRM) mass spectrometry method for the simultaneous quantification of the Arg/nitric oxide (NO) pathway metabolites. This methodology was then employed to quantify the plasma concentrations of these analytes in a cohort of individuals with different grades/types of coronary artery disease (CAD) in order to increase knowledge about the role of HArg and its associated metabolites in the CV field. Our results showed that the MRM method here implemented is suitable for the simultaneous assessment of a wide panel of amino acids involved in the Arg/NO metabolic pathway in plasma samples from patients with CV disease. Further, our findings highlighted an impairment of the Arg/NO metabolic pathway, and suggest a sex-dependent regulation of this metabolic route.

Cholecalciferol and metformin protect against lipopolysaccharide-induced endothelial dysfunction and senescence by modulating sirtuin-1 and protein arginine methyltransferase-1

Endothelial cell activation through nuclear factor-kappa-B (NFkB) and mitogen-activated protein kinases leads to increased biosynthesis of pro-inflammatory mediators, cellular injury and vascular inflammation under lipopolysaccharide (LPS) exposure. Recent studies report that LPS up-regulated global methyltransferase activity. In this study, we observed that a combination treatment with metformin (MET) and cholecalciferol (VD) blocked the LPS-induced S-adenosylmethionine (SAM)-dependent methyltransferase (SDM) activity in Eahy926 cells. We found that LPS challenge (i) increased arginine methylation through up-regulated protein arginine methyltransferase-1 (PRMT1) mRNA, intracellular concentrations of asymmetric dimethylarginine (ADMA) and homocysteine (HCY); (ii) up-regulated cell senescence through mitigated sirtuin-1 (SIRT1) mRNA, nicotinamide adenine dinucleotide (NAD+) concentration, telomerase activity and total antioxidant capacity; and (iii) lead to endothelial dysfunction through compromised nitric oxide (NOx) production. However, these LPS-mediated cellular events in Eahy926 cells were restored by the synergistic effect of MET and VD. Taken together, this study identified that the dual compound effect inhibits LPS-induced protein arginine methylation, endothelial senescence and dysfunction through the components of epigenetic machinery, SIRT1 and PRMT1, which is a previously unidentified function of the test compounds. In silico results identified the presence of vitamin D response element (VDRE) sequence on PRMT1 suggesting that VDR could regulate PRMT1 gene expression. Further characterization of the cellular events associated with the dual compound challenge, using gene silencing approach or adenoviral constructs for SIRT1 and/or PRMT1 under inflammatory stress, could identify therapeutic strategies to address the endothelial consequences in vascular inflammation-mediated atherosclerosis.

Developing a robust, fast and reliable measurement method for the analysis of methylarginine derivatives and related metabolites

Background

Nitric oxide (NO) plays an important role in endothelial homeostasis. Asymmetric dimethyl arginine (ADMA), L-N monomethyl arginine (L-NMMA) and symmetric dimethyl arginine (SDMA), which are derivatives of methylarginine, directly or indirectly reduce NO production. Therefore, these metabolites are an important risk factor for various diseases, including cardiovascular diseases. Numerous methods have been developed for the measurement of methylarginine derivatives, but various difficulties have been encountered. This study aimed to develop a reliable, fast and cost-effective method for the analysis and measurement of methylarginine derivatives (ADMA, SDMA, L-NMMA) and related metabolites (arginine, citrulline, homoarginine, ornithine), and to validate this method according to Clinical and Laboratory Standards Institute (CLSI) protocols.

Methods

For the analysis of ADMA, SDMA, L-NMMA, arginine, homoarginine, citrulline, ornithine, 200 Âµl of serum were precipitated with methanol, and subsequently derivatized with a butanol solution containing 5% acetyl chloride. Butyl derivatives were separated using a C18 reverse phase column with a 5 min run time. Detection of analytes was achieved by utilising the specific fragmentation patterns identified through tandem mass spectrometry.

Results

The method was linear for ADMA, SDMA, L-NMMA, ornithine, arginine, homoarginine and citrulline in the ranges of 0.023–6.0, 0.021–5.5, 0.019–5.0, 0.015–250, 0.015–250, 0.019–5 and 0.015–250 µM, respectively. The inter-assay CV% values for all analytes was less than 9.8%.

Conclusions

Data obtained from method validation studies shows that the developed method is highly sensitive, precise and accurate. Short analysis time, cost-effectiveness, and multiplexed analysis of these metabolites, with the same pretreatment steps, are the main advantages of the method.

Renoprotection Induced by Aerobic Training Is Dependent on Nitric Oxide Bioavailability in Obese Zucker Rats

Aerobic training (AT) promotes several health benefits that may attenuate the progression of obesity associated diabetes. Since AT is an important nitric oxide (NO⁻) inducer mediating kidney-healthy phenotype, the present study is aimed at investigating the effects of AT on metabolic parameters, morphological, redox balance, inflammatory profile, and vasoactive peptides in the kidney of obese-diabetic Zucker rats receiving L-NAME (N(omega)-nitro-L-arginine methyl ester). Forty male Zucker rats (6 wk old) were assigned into four groups (n = 10, each): sedentary lean rats (CTL-Lean), sedentary obese rats (CTL-Obese), AT trained obese rats without blocking nitric oxide synthase (NOS) (Obese+AT), and obese-trained with NOS block (Obese+AT+L-NAME). AT groups ran 60 min in the maximal lactate steady state (MLSS), five days/wk/8 wk. Obese+AT rats improved glycemic homeostasis, SBP, aerobic capacity, renal mitochondria integrity, redox balance, inflammatory profile (e.g., TNF-α, CRP, IL-10, IL-4, and IL-17a), and molecules related to renal NO⁻ metabolism (klotho/FGF23 axis, vasoactive peptides, renal histology, and reduced proteinuria). However, none of these positive outcomes were observed in CTL-Obese and Obese+AT+L-NAME (p < 0.0001) groups. Although Obese+AT+L-NAME lowered BP (compared with CTL-Obese; p < 0.0001), renal damage was observed after AT intervention. Furthermore, AT training under conditions of low NO⁻ concentration increased signaling pathways associated with ACE-2/ANG1-7/MASr. We conclude that AT represents an important nonpharmacological intervention to improve kidney function in obese Zucker rats. However, these renal and metabolic benefits promoted by AT are dependent on NO⁻ bioavailability and its underlying regulatory mechanisms.

Asymmetric Dimethylarginine (ADMA) in Pediatric Renal Diseases: From Pathophysiological Phenomenon to Clinical Biomarker and Beyond

Asymmetric dimethylarginine (ADMA), an endogenous nitric oxide (NO) synthase inhibitor, inhibits NO synthesis and contributes to the pathogenesis of many human diseases. In adults, ADMA has been identified as a biomarker for chronic kidney disease (CKD) progression and cardiovascular risk. However, little attention is given to translating the adult experience into the pediatric clinical setting. In the current review, we summarize circulating and urinary ADMA reported thus far in clinical studies relating to kidney disease in children and adolescents, as well as systematize the knowledge on pathophysiological role of ADMA in the kidneys. The aim of this review is also to show the various analytical methods for measuring ADMA and the issues tht need to be addressed before transforming to clinical practice in pediatric medicine. The last task is to suggest that ADMA may not only be suitable as a diagnostic or prognostic biomarker, but also a promising therapeutic strategy to treat pediatric kidney disease in the future.

Resveratrol prevented spatial deficits and rescued disarrayed hippocampus asymmetric dimethylarginine and brain-derived neurotrophic factor levels in young rats with increased circulating asymmetric dimethylarginine

Increased plasma levels of asymmetric dimethylarginine can be encountered in chronic inflammatory disease, liver damage, renal failure, and multiple organ failure. In addition, an association between circulating asymmetric dimethylarginine levels and all-cause mortality has been reported. Male Sprague-Dawley rats, postnatal day 17 ± 1, received continuous asymmetric dimethylarginine infusion via an intraperitoneal pump. Spatial performance and dorsal hippocampal asymmetric dimethylarginine and brain-derived neurotrophic factor (BDNF) levels were examined, and the effect of resveratrol was tested. A 4-week continuous asymmetric dimethylarginine infusion in young male rats caused spatial deficits, increased asymmetric dimethylarginine levels, and decreased BDNF expression in the dorsal hippocampus. Increased oxidative stress and altered molecules in the dorsal hippocampus linked to asymmetric dimethylarginine and BDNF functions were detected. Resveratrol protected against these effects, reversing spatial deficits, and reducing the changes in the dorsal hippocampal asymmetric dimethylarginine and BDNF levels.

Non-functioning adrenal incidentalomas may increase toxic metabolites

BACKGROUND

Non-functioning adrenal incidentaloma (NFAI) is a frequent diagnosis with increasing radiological tests. The emerging shreds of evidence showed that they might have negative cardiometabolic effects. The study aimed to investigate whether the toxic metabolites, asymmetric dimethylarginine (ADMA) levels, were altered in NFAI patients.

METHODS

We included 43 NFAI patients and 41 controls with similar ages and body mass indices in the study. We compared plasma ADMA levels of both groups and noted the radiological features of NFAIs.

RESULTS

The ADMA levels were significantly higher in NFAI patients than in the control group (307.04 ng/ml, range 81.89-577.7 ng/ml vs 192.54 ng/ml, range 70.61-440.26 ng/ml, p = 0.001). Nevertheless, we could not reach a significant correlation between ADMA levels and mass size.

CONCLUSION

The ADMA is known as a toxin and is increased in NFAI patients. NFAIs may not be innocent and may be considered a potential risk for the body. Further investigations were needed for more explanations.

Endothelial Dysfunction Driven by Hypoxia-The Influence of Oxygen Deficiency on NO Bioavailability

Cardiovascular diseases (CVDs) are the leading cause of death worldwide. The initial stage of CVDs is characterized by endothelial dysfunction, defined as the limited bioavailability of nitric oxide (NO). Thus, any factors that interfere with the synthesis or metabolism of NO in endothelial cells are involved in CVD pathogenesis. It is well established that hypoxia is both the triggering factor as well as the accompanying factor in cardiovascular disease, and diminished tissue oxygen levels have been reported to influence endothelial NO bioavailability. In endothelial cells, NO is produced by endothelial nitric oxide synthase (eNOS) from L-Arg, with tetrahydrobiopterin (BH₄) as an essential cofactor. Here, we discuss the mechanisms by which hypoxia affects NO bioavailability, including regulation of eNOS expression and activity. What is particularly important is the fact that hypoxia contributes to the depletion of cofactor BH₄ and deficiency of substrate L-Arg, and thus elicits eNOS uncoupling-a state in which the enzyme produces superoxide instead of NO. eNOS uncoupling and the resulting oxidative stress is the major driver of endothelial dysfunction and atherogenesis. Moreover, hypoxia induces impairment in mitochondrial respiration and endothelial cell activation; thus, oxidative stress and inflammation, along with the hypoxic response, contribute to the development of endothelial dysfunction.

Decreased Expression and Uncoupling of Endothelial Nitric Oxide Synthase in the Cerebral Cortex of Rats with Thioacetamide-Induced Acute Liver Failure

Acute liver failure (ALF) is associated with deregulated nitric oxide (NO) signaling in the brain, which is one of the key molecular abnormalities leading to the neuropsychiatric disorder called hepatic encephalopathy (HE). This study focuses on the effect of ALF on the relatively unexplored endothelial NOS isoform (eNOS). The cerebral prefrontal cortices of rats with thioacetamide (TAA)-induced ALF showed decreased eNOS expression, which resulted in an overall reduction of NOS activity. ALF also decreased the content of the NOS cofactor, tetrahydro-L-biopterin (BH4), and evoked eNOS uncoupling (reduction of the eNOS dimer/monomer ratio). The addition of the NO precursor L-arginine in the absence of BH4 potentiated ROS accumulation, whereas nonspecific NOS inhibitor L-NAME or EDTA attenuated ROS increase. The ALF-induced decrease of eNOS content and its uncoupling concurred with, and was likely causally related to, both increased brain content of reactive oxidative species (ROS) and decreased cerebral cortical blood flow (CBF) in the same model.

Interplay Between Reactive Oxygen/Reactive Nitrogen Species and Metabolism in Vascular Biology and Disease

Reactive oxygen species (ROS; e.g., superoxide [O₂^•-] and hydrogen peroxide [H₂O₂]) and reactive nitrogen species (RNS; e.g., nitric oxide [NO^•]) at the physiological level function as signaling molecules that mediate many biological responses, including cell proliferation, migration, differentiation, and gene expression. By contrast, excess ROS/RNS, a consequence of dysregulated redox homeostasis, is a hallmark of cardiovascular disease. Accumulating evidence suggests that both ROS and RNS regulate various metabolic pathways and enzymes. Recent studies indicate that cells have mechanisms that fine-tune ROS/RNS levels by tight regulation of metabolic pathways, such as glycolysis and oxidative phosphorylation. The ROS/RNS-mediated inhibition of glycolytic pathways promotes metabolic reprogramming away from glycolytic flux toward the oxidative pentose phosphate pathway to generate nicotinamide adenine dinucleotide phosphate (NADPH) for antioxidant defense. This review summarizes our current knowledge of the mechanisms by which ROS/RNS regulate metabolic enzymes and cellular metabolism and how cellular metabolism influences redox homeostasis and the pathogenesis of disease. A full understanding of these mechanisms will be important for the development of new therapeutic strategies to treat diseases associated with dysregulated redox homeostasis and metabolism. Antioxid. Redox Signal. 34, 1319-1354.

The impact of reactive oxygen species in the development of cardiometabolic disorders: a review

Oxidative stress, an alteration in the balance between reactive oxygen species (ROS) generation and antioxidant buffering capacity, has been implicated in the pathogenesis of cardiometabolic disorders (CMD). At physiological levels, ROS functions as signalling mediators, regulates various physiological functions such as the growth, proliferation, and migration endothelial cells (EC) and smooth muscle cells (SMC); formation and development of new blood vessels; EC and SMC regulated death; vascular tone; host defence; and genomic stability. However, at excessive levels, it causes a deviation in the redox state, mediates the development of CMD. Multiple mechanisms account for the rise in the production of free radicals in the heart. These include mitochondrial dysfunction and uncoupling, increased fatty acid oxidation, exaggerated activity of nicotinamide adenine dinucleotide phosphate oxidase (NOX), reduced antioxidant capacity, and cardiac metabolic memory. The purpose of this study is to discuss the link between oxidative stress and the aetiopathogenesis of CMD and highlight associated mechanisms. Oxidative stress plays a vital role in the development of obesity and dyslipidaemia, insulin resistance and diabetes, hypertension via various mechanisms associated with ROS-led inflammatory response and endothelial dysfunction.

Is there a relation between serum methylarginine levels and infertility?

OBJECTIVES

Infertility is defined as the absence of pregnancy within the reproductive period despite regular sexual intercourse. Methylarginines are formed as a result of methylation of arginine residues in proteins and formed in three forms as asymmetric dimethyl arginine (ADMA), symmetrical dimethyl arginine (SDMA) and monomethylarginine (L-NMMA). So, here, we aimed to evaluate arginine and their derivatives levels in fertile and infertile individuals.

METHODS

Present study were consist of 30 oligozoospermia patients (proven by spermiogram analysis) and 30 healthy individuals with normozoospermia group who were applied to the urology department. With blood samples taken from individuals, serum methylarginine and its derivatives levels were analyzed by liquid chromatography-tandem mass spectrometry (LC-MS/MS). Clinic data and demographic characteristics of individuals were also recorded at the same time.

RESULTS

The serum ADMA level (0.38 ± 0.07) of the oligozoospermia group was found to be significantly higher than the normozoospermia group (0.35 ± 0.05) (p=0.046). A positive correlation were observed between ADMA and SDMA (r=0.686, p=0.000), HArg and SDMA (r=0.611, p=0.001), citrulline and L-NMMA (r=0.595, p=0.001) in patients with oligosospermia. The increase in SDMA, arginine and HArg levels and a decrease in L-NMMA and citrulline levels were not significant as statistically. Also, the ADMA level was found to be high in individuals with low sperm concentration.

CONCLUSIONS

Consequently, serum ADMA levels of individuals with oligozoospermia were statistically significantly higher than those with normozoospermia. As proposal, determination of ADMA levels may be a potential biomarker parameter in terms of early diagnosis of fertility and infertility.

A Multi-Platform Metabolomics Approach Identifies Urinary Metabolite Signatures That Differentiate Ketotic From Healthy Dairy Cows

Ketosis and subclinical ketosis are widespread among dairy cows especially after calving. Etiopathology of ketosis has been related to negative energy balance. The objective of this study was to investigate metabolite fingerprints in the urine of pre-ketotic, ketotic, and post-ketotic cows to identify potential metabolite alterations that can be used in the future to identify susceptible cows for ketosis and metabolic pathways involved in the development of disease. In this study, NMR, DI/LC-MS/MS, and GC-MS-based metabolomics were used to analyze urine samples from 6 cows diagnosed with ketosis and 20 healthy control (CON) cows at -8 and -4 weeks prepartum, the week (+1 to +3) of ketosis diagnosis, and at +4 and +8 weeks after parturition. Univariate and multivariate analyses were used to screen metabolite panels that can identify cows at their pre-ketotic stage. A total of 54, 42, 48, 16, and 31 differential metabolites between the ketotic and CON cows were identified at -8 and -4 weeks prepartum, ketosis week, and at +4, and +8 weeks postpartum, respectively. Variable importance in projection (VIP) plots ranked the most significant differential metabolites, which differentiated ketotic cows from the CON ones. Additionally, several metabolic pathways that are related to ketosis were identified. Moreover, two promising metabolite panels were identified which clearly separated ketotic from CON cows with excellent level of sensitivity and specificity. Overall, multiple urinary metabolite alterations were identified in pre-ketotic, ketotic, and post-ketotic cows. The metabolite panels identified need to be validated in the future in a larger cohort of animals.

Inhibition of Rho-kinase is involved in the therapeutic effects of atorvastatin in heart ischemia/reperfusion

The aim of the present study was to investigate the effects of atorvastatin against heart ischemia/reperfusion (I/R) injury and its potential underlying mechanism. Rats were allocated into the following groups: Sham, I/R, atorvastatin (10 mg/kg daily), fasudil (10 mg/kg daily) and atorvastatin + fasudil in combination. Drugs were administered for 2 weeks prior to I/R injury. I/R was established by ligating the left anterior descending branch (LAD) for 30 min and releasing the ligature for 180 min. The I/R group was found to have increased myocardial infarct size, cardiomyocyte apoptosis, levels of plasma interleukin (IL)-6 and tumor necrosis factor (TNF)-α, superoxide dismutase (SOD) activity, malondialdehyde (MDA) levels and Rho-kinase activity compared with the other treatment groups (P<0.05). Moreover, pretreatment with atorvastatin significantly attenuated Rho-kinase activity, myocardial infarct size, cardiomyocyte apoptosis, levels of plasma IL-6 and TNF-α, SOD activity and MDA levels, and upregulated nitric oxide production. It was also indicated that the specific Rho-kinase inhibitor, fasudil, had the same effects as atorvastatin in I/R. Therefore, the present results suggested atorvastatin may lead to cardiovascular protection, which may be mediated by Rho-kinase inhibition in heart I/R injury.

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.

Increased Serum Levels of Asymmetric Dimethylarginine and Symmetric Dimethylarginine and Decreased Levels of Arginine in Sudanese Patients with Essential Hypertension

INTRODUCTION

Essential hypertension (EH) is a disease caused by various environmental and genetic factors. Nitric oxide (NO) is important for the functional integrity of the endothelium. It is produced in endothelial cells by endothelial NO synthase (eNOS) that mediates the conversion of the amino acid arginine into NO and citrulline. Asymmetric dimethylarginine (ADMA) acts as an inhibitor of eNOS. In contrast, symmetric dimethylarginine (SDMA) has no direct effect on eNOS but plays an important role competing with arginine for transport across the amino acid transporter. ADMA and SDMA have been found to play a central role in the development of cardiovascular diseases. Serum ADMA levels may serve as a future diagnostic marker and a target of therapy in hypertensive patients in the Sudanese population. This study aimed to investigate the relation between serum arginine, ADMA, and SDMA levels with EH in the Sudanese population.

METHODS

Patients (n = 260) with established hypertension and controls (n = 144) with normal blood pressure were included in this case-control study. Serum blood samples were analyzed for arginine, ADMA, and SDMA, using high-performance liquid chromatography-tandem mass spectrometry. Other laboratory data were measured using routine methods. Mann-Whitney's U test and χ2 tests were used for continuous and categorical data, respectively. A multivariate logistic regression analysis was conducted to investigate the independent effect of multiple variables on the development of hypertension.

RESULTS

Serum arginine levels were significantly lower in the patient group than in the control group (p < 0.001). ADMA and SDMA levels were significantly higher in the patient group than the control group (p < 0.001, p = 0.001, respectively). Multivariate logistic regression analysis showed that only older age, being a male, and arginine levels are independent factors controlling the development of hypertension (p < 0.001, p < 0.001, and p = 0.046, respectively). ADMA and SDMA levels were not independent factors for the development of hypertension.

CONCLUSIONS

This study demonstrated increased serum levels of ADMA and SDMA and decreased arginine levels in Sudanese patients with EH. Lowering serum ADMA levels or increasing the arginine levels might be a novel therapeutic target in these individuals.

New Oxidative Stress Markers Useful in the Diagnosis of Acute Appendicitis in Children: Thiol/Disulfide Homeostasis and the Asymmetric Dimethylarginine Level

OBJECTIVES

The aim of this study was to evaluate 2 new oxidative stress markers, thiol/disulfide homeostasis status and the asymmetric dimethylarginine (ADMA) level, in children with acute appendicitis (AA) and to evaluate their diagnostic utility.

METHODS

This case-control study included 45 patients with AA and 35 healthy children. Age, sex, white blood cell count, neutrophil-to-lymphocyte ratio, high-sensitivity C-reactive protein (hs-CRP) level, ultrasonographic findings, thiol/disulfide homeostasis parameters (native and total thiol levels, native thiol/total thiol ratios [antioxidant parameters], and disulfide, disulfide/native thiol, and disulfide/total thiol ratios [oxidant parameters]), and the ADMA level were compared between the 2 groups.

RESULTS

The native and total thiol levels, and the native thiol/total thiol ratio, were significantly lower, and the disulfide level and disulfide/native thiol and disulfide/total thiol ratios significantly higher, in the AA compared with the control group (all P < 0.001). The ADMA level was significantly higher in a perforated versus nonperforated subgroup of AA patients, but the thiol/disulfide homeostasis parameters did not differ significantly between the two subgroups. In addition, the hs-CRP level and appendiceal wall thickness were higher in the perforated subgroup. The thiol/disulfide antioxidant parameters and ADMA level correlated negatively with the white blood cell count, the neutrophil-to-lymphocyte ratio, and the hs-CRP level, in the AA group, but correlated positively with oxidant parameters. The sensitivity and specificity of the disulfide/native thiol and disulfide/total thiol ratios were high when used to diagnose AA, whereas the sensitivity of the ADMA level was high when used to diagnose perforated appendicitis.

CONCLUSIONS

Thiol/disulfide homeostasis and the ADMA level, together with certain other parameters, may be useful biomarkers of AA in children.

The Usefulness of Serum Biomarkers in the Early Stages of Diabetic Retinopathy: Results of the EUROCONDOR Clinical Trial

The main aim of this study was to evaluate the ability of serum biomarkers to predict the worsening of retinal neurodysfunction in subjects with type 2 diabetes. For this purpose, we measured selected molecules (N-epsilon-carboxy methyl lysine (CML), laminin P1 (Lam-P1), and asymmetric dimethylarginine (ADMA)) in the serum of 341 participants of the EUROCONDOR study at baseline, 24, and 48 weeks. Retinal neurodysfunction was assessed by measuring implicit time (IT) using multifocal electroretinography, and structural changes were examined by spectral domain–optical coherence tomography. The values of IT at baseline were directly correlated with baseline serum concentrations of CML (r = 0.135, p = 0.013). Furthermore, in the placebo group, increase in CML concentration throughout follow-up correlated with the IT (r = 0.20; p = 0.03). Baseline serum levels of CML also correlated with macular retinal thickness (RT) (r = 0.231; p < 0.001). Baseline Lam-P1 levels correlated with the increase of the RT at the end of follow-up in the placebo group (r = 0.22; p = 0.016). We provide evidence that CML may be a biomarker of both retinal neurodysfunction and RT, whereas Lam-P1 was associated with RT only. Therefore, circulating levels of these molecules could provide a complementary tool for monitoring the early changes of diabetic retinopathy (DR).

Oxidative stress and inflammation contribute to traffic noise-induced vascular and cerebral dysfunction via uncoupling of nitric oxide synthases

Environmental pollution and non-chemical stressors such as mental stress or traffic noise exposure are increasingly accepted as health risk factors with substantial contribution to chronic noncommunicable diseases (e.g. cardiovascular, metabolic and mental). Whereas the mechanisms of air pollution-mediated adverse health effects are well characterized, the mechanisms of traffic noise exposure are not completely understood, despite convincing clinical and epidemiological evidence for a significant contribution of environmental noise to overall mortality and disability. The initial mechanism of noise-induced cardiovascular, metabolic and mental disease is well defined by the „noise reaction model“ and consists of neuronal activation involving the hypothalamic-pituitary-adrenal (HPA) axis as well as the sympathetic nervous system, followed by a classical stress response via cortisol and catecholamines. Stress pathways are initiated by noise-induced annoyance and sleep deprivation/fragmentation. This review highlights the down-stream pathophysiology of noise-induced mental stress, which is based on an induction of inflammation and oxidative stress. We highlight the sources of reactive oxygen species (ROS) involved and the known targets for noise-induced oxidative damage. Part of the review emphasizes noise-triggered uncoupling/dysregulation of endothelial and neuronal nitric oxide synthase (eNOS and nNOS) and its central role for vascular dysfunction.

•

Exposure to (traffic) noise causes non-auditory (indirect) cardiovascular and cerebral health harms via neuronal activation.

•

Noise activates the HPA axis and sympathetic nervous system increasing levels of stress hormones, vasoconstrictors and ROS.

•

Noise induces inflammation and stimulates several ROS sources leading to cerebral and cardiovascular oxidative damage.

•

Noise leads to eNOS and nNOS uncoupling contributing to cardiometabolic disease and cognitive impairment.

The effect of resveratrol supplementation on serum levels of asymmetric de-methyl-arginine and paraoxonase 1 activity in patients with type 2 diabetes: A randomized, double-blind controlled trial

The present study sought to investigate the effect of micronized resveratrol supplementation on serum levels of asymmetric de-methyl-arginine (ADMA) and paraoxonase-1 (PON1) activity in patients with type 2 diabetes (T2D). In this double-blinded randomized trial, 76 patients with T2D were recruited. Participants were randomly assigned to consume 1,000 mg resveratrol or placebo capsules (methylcellulose) per day, for 8 weeks. Serum levels of ADMA and PON1 enzyme activity were measured at the beginning and end of the intervention using the enzyme-linked immunosorbent assay method. In total, 71 participants completed the study. Our results showed that resveratrol significantly decreased serum levels of ADMA (-0.16 ± 0.11, p < .001) and improved PON1 enzyme activity (15.39 ± 13.99, p < .001) compared with placebo, after adjusting for confounding factors (age, sex, and baseline body mass index). Our findings suggest that 8-week resveratrol supplementation may produce beneficial effects on serum levels of ADMA and PON1 enzyme activity in patients with T2DM. However, further research is needed to confirm the veracity of these results.

Arginine Derivatives in Cerebrovascular Diseases: Mechanisms and Clinical Implications

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

Role of reactive oxygen species in atherosclerosis: Lessons from murine genetic models

Atherosclerosis is a multifactorial chronic and inflammatory disease of medium and large arteries, and the major cause of cardiovascular morbidity and mortality worldwide. The pathogenesis of atherosclerosis involves a number of risk factors and complex events including hypercholesterolemia, endothelial dysfunction, increased permeability to low density lipoproteins (LDL) and their sequestration on extracellular matrix in the intima of lesion-prone areas. These events promote LDL modifications, particularly by oxidation, which generates acute and chronic inflammatory responses implicated in atherogenesis and lesion progression. Reactive oxygen species (ROS) (which include both free radical and non-free radical oxygen intermediates), play a key-role at each step of atherogenesis, in endothelial dysfunction, LDL oxidation, and inflammatory events involved in the initiation and development of atherosclerosis lesions. Most advanced knowledge supporting the "oxidative theory of atherosclerosis" i.e. the nature and the cellular sources of ROS and antioxidant defences, as well as the mechanisms involved in the redox balance, is based on the use of genetically engineered animals, i.e. transgenic, genetically modified, or altered for systems producing or neutralizing ROS in the vessels. This review summarizes the results obtained from animals genetically manipulated for various sources of ROS or antioxidant defences in the vascular wall, and their relevance (advance or limitation), for understanding the place and role of ROS in atherosclerosis.

The Effect of Vitamin D on Serum Asymmetric Dimethylarginine in Patients with Mild to Moderate Ulcerative Colitis

Abstract. Purpose: In inflammatory bowel disease increased asymmetric dimethylarginine (ADMA) levels could inhibit nitric oxide (NO) synthase. Vitamin D may increase activity and expression of endothelial NO synthase, which could be done through its possible mechanism of decreasing ADMA levels. The aim of this study is to investigate the possible effect of Vitamin D3 on serum ADMA levels in ulcerative colitis (UC) patients. Methods: Ninety mild to moderate UC patients were randomized. Each patient received one single muscular injection of 300,000 IU (7500 μg) Vitamin D3 (Vitamin D group) or 1 ml normal saline (Placebo group). At baseline and 90 days after the intervention measurements were done. Data were analyzed using independent t-test and analysis of covariance. Baseline correlations were assessed by Pearson and Spearman correlation coefficients. Results: Following data analysis of 86 participants (40 in placebo and 46 in vitamin D group), there was no correlation between baseline ADMA with baseline vitamin D, ESR and hs-CRP at baseline (p = 0.77) and at the end of study (p = 0.82). Serum ADMA levels were not statistically different between two groups. Adjustment for baseline ADMA levels and baseline body mass index (BMI) did not change the results. With subgroup analyses based on gender and vitamin D level no statistical differences in ADMA levels between two groups were found. Conclusions: In this study, we found no significant changes in serum ADMA levels 3 months following a high dose vitamin D administration in mild to moderate UC patients. Further studies in vitamin D deficient patients are needed.

Asymmetric and symmetric dimethylarginine concentration as an indicator of cardiovascular diseases in rheumatoid arthritis patients: a systematic review and meta-analysis of case-control studies

Rheumatoid arthritis (RA) is the most common type of inflammatory arthritis leading to joint damage and physical disability. Cardiovascular diseases (CVDs) are considered a common comorbidity in patients with RA. However, the mechanism underlying its pathogenesis is not definitively explained. Endothelial dysfunction caused by impaired nitric oxide synthesis is an early indicator of cardiovascular disease. Asymmetric and symmetric dimethylarginine (ADMA and SDMA, respectively) the inhibitors of endothelial nitric oxide synthase (NOS) have emerged as novel CVD risk factor determiners. Concerning the unmet need to identify a salutary biomarker for CVD prediction, the purpose of this meta-analysis was to assess the serum/plasma ADMA and SDMA levels in RA patients compared with the healthy controls. A thorough literature search was performed in PubMed, Scopus, Web of Science, and Google Scholar to identify all studies reporting ADMA and/or SDMA levels in RA patients compared with healthy controls. The quality of studies was evaluated using the Newcastle-Ottawa scale (NOS). Pooled standard mean difference (SMD) with 95% confidence interval (CI) was used as the effect size in this study. We also conducted stratified analysis based on assay methods and median age of the participants. Fourteen articles were included. The pooled serum/plasma levels of ADMA were higher in RA patients compared with those of healthy controls (SMD = 1.02, 95% CI = 0.49 to 1.55); However, no statistical differences between RA patients and healthy controls in serum/plasma SDMA levels was seen (SMD = 0.57, 95% CI = -0.21 to 1.36). Subgroup analyses suggested that participants aged > 50 years had higher levels of ADMA rather than controls and the measurement method was a source of heterogeneity for ADMA. According to the results of this meta-analysis, ADMA measurement but not SDMA, can be useful for assessment of endothelial dysfunction as a predictor of CVD risk in RA patients. Prospero registration number: CRD42019121126.

Utility of time of onset of hypertension, ADMA and TAS in predicting adverse neonatal outcome in hypertensive disorders of pregnancy

Background: Limited studies have been conducted to evaluate the utility of indices for the prediction of the adverse neonatal outcomes in hypertensive disorders of pregnancy (HDP).Method: A total of 174 pregnant women with HDP (gestational hypertension, late onset preeclampsia, and early onset preeclampsia) and 49 controls were sampled during the third trimester. Preterm birth, low birth weight, fetal, and infant mortality and low Apgar scores were assessed.Results: Multivariate analysis confirmed systolic blood pressure (SBP), time of onset of hypertension (TOH), and total antioxidant status (TAS) as predictors of preterm births; TOH and diastolic blood pressure (DBP) to be predictors of low birth weight babies; TOH and asymmetric dimethyl arginine (ADMA) as predictors of fetal mortality and babies with low Apgar at 5 min. We found TOH as the single best predictor for adverse neonatal outcomes.Conclusion: This study identified TOH as an important predictor of most of the adverse neonatal outcomes.

A Detailed Insight of the Anti-inflammatory Effects of Curcumin with the Assessment of Parameters, Sources of ROS and Associated Mechanisms

Background:

Curcumin is an active constituent ofCurcuma longa,which belongs to Zingiberaceae family. It is derived from the Rhizome of a perennial plant having molecular formula C21H20O6and chemically it is (1, 7- bis (4- hydroxy - 3 methoxyphenyl) -1, 6 - heptadine - 3, 5 - diene), also known as diferuloylmethane. Curcumin has been extensively used as a herbal constituent for curing several diseases and is scientifically proven to show major effects as an anti-inflammatory agent.

Objective:

Inflammation is an important factor for numerous diseases including diabetes neuropathy, cancer, asthma, arthritis, and other diseases. Prophylaxis of inflammatory diseases through synthetic medications tends to have major toxicity and side effects on a large number of population. The foremost aim of this review paper is to assess the natural anti-inflammatory effect of curcumin, source, and mechanism of action, potential therapeutic effect and models associated. Additionally, this paper aims to scrutinize inflammation, sources of reactive oxygen species, and pathways of reactive oxygen species generation and potential side effects of curcumin.

Methods:

Selection of data has been done by studying the combination of research and review papers from different databases like PubMed, Medline and Web of science from the year 1985- 2018 by using search keywords like “curcumin”, “anti-inflammatory”, “ROS”, “Curcuma longa”, “medicinal uses of curcumin”, “assessing parameters”, “inflammation”, “anti-oxidant”

Results:

On the basis of our interpretation, we have concluded that curcumin has potential therapeutic effects in different inflammatory diseases, it inhibits the inflammatory mediators, oxidation processes, and oxidative stress and has no severe toxicity on animals and humans.

Conclusion:

Oxidative stress is a major cause of inflammation and curcumin has a good potential for blocking it. Curcumin is also easily accessible herbal source and should be consumed in the form of food, antioxidant, anti-inflammatory agents and further observation should be done on its therapeutic parameters, risk factors, and toxicity studies and oral viability.