Effect of asymmetric dimethylarginine (ADMA) on heart failure development

Comparative transcriptome and methylome of polar bears, giant and red pandas reveal diet-driven adaptive evolution

Epigenetic regulation plays an important role in the evolution of species adaptations, yet little information is available on the epigenetic mechanisms underlying the adaptive evolution of bamboo-eating in both giant pandas (Ailuropoda melanoleuca) and red pandas (Ailurus fulgens). To investigate the potential contribution of epigenetic to the adaptive evolution of bamboo-eating in giant and red pandas, we performed hepatic comparative transcriptome and methylome analyses between bamboo-eating pandas and carnivorous polar bears (Ursus maritimus). We found that genes involved in carbohydrate, lipid, amino acid, and protein metabolism showed significant differences in methylation and expression levels between the two panda species and polar bears. Clustering analysis of gene expression revealed that giant pandas did not form a sister group with the more closely related polar bears, suggesting that the expression pattern of genes in livers of giant pandas and red pandas have evolved convergently driven by their similar diets. Compared to polar bears, some key genes involved in carbohydrate metabolism and biological oxidation and cholesterol synthesis showed hypomethylation and higher expression in giant and red pandas, while genes involved in fat digestion and absorption, fatty acid metabolism, lysine degradation, resistance to lipid peroxidation and detoxification showed hypermethylation and low expression. Our study elucidates the special nutrient utilization mechanism of giant pandas and red pandas and provides some insights into the molecular mechanism of their adaptive evolution of bamboo feeding. This has important implications for the breeding and conservation of giant pandas and red pandas.

A Set of Possible Markers for Monitoring Heart Failure and Cognitive Impairment Associated: A Review of Literature from the Past 5 Years

BACKGROUND

Heart failure is an epidemiologically relevant disease because of the aging population and widespread lifestyles that promote it. In addition to the acute event, it is possible for the disease to become chronic with periodic flare-ups. It is essential to study pathology from a diagnostic and prognostic point of view and to identify parameters for effective monitoring. In addition, heart failure is associated with multiple comorbidities, including cognitive impairment, which is monitored clinically but not through specific biomarkers in these patients. The purpose of this review is to gather the most recent scientific evidence on a few possible biomarkers previously identified for monitoring heart failure and associated cognitive impairment.

METHODS

We surveyed studies inherent to a set of previously identified markers, evaluating English-language articles from the past five years conducted in adult heart failure patient populations. We used the databases PubMed, Web of Sciences, and Cochrane Library for search studies, and we considered articles published in journals with an impact factor greater than five in the publication year.

RESULTS

Among the biomarkers evaluated, a concordant indication for serial measurements for heart failure monitoring emerged only for interleukin-6. For the other markers, there is still little evidence available, which is interesting but sometimes conflicting. Interesting studies have also emerged for biomarkers of cognitive decline assessed in patients with heart failure, confirming the hypotheses of the increasingly studied heart-brain correlation.

CONCLUSION

Certainly, further studies in large populations are needed to identify effective biomarkers for monitoring heart failure and associated cognitive impairment.

Dysfunctional and Dysregulated Nitric Oxide Synthases in Cardiovascular Disease: Mechanisms and Therapeutic Potential

Nitric oxide (NO) plays an important and diverse signalling role in the cardiovascular system, contributing to the regulation of vascular tone, endothelial function, myocardial function, haemostasis, and thrombosis, amongst many other roles. NO is synthesised through the nitric oxide synthase (NOS)-dependent L-arginine-NO pathway, as well as the nitrate-nitrite-NO pathway. The three isoforms of NOS, namely neuronal (NOS1), inducible (NOS2), and endothelial (NOS3), have different localisation and functions in the human body, and are consequently thought to have differing pathophysiological roles. Furthermore, as we continue to develop a deepened understanding of the different roles of NOS isoforms in disease, the possibility of therapeutically modulating NOS activity has emerged. Indeed, impaired (or dysfunctional), as well as overactive (or dysregulated) NOS activity are attractive therapeutic targets in cardiovascular disease. This review aims to describe recent advances in elucidating the physiological role of NOS isoforms within the cardiovascular system, as well as mechanisms of dysfunctional and dysregulated NOS in cardiovascular disease. We then discuss the modulation of NO and NOS activity as a target in the development of novel cardiovascular therapeutics.

Modulation of the nitric oxide/cGMP pathway in cardiac contraction and relaxation: Potential role in heart failure treatment

Evidence exists that heart failure (HF) has an overall impact of 1-2 % in the global population being often associated with comorbidities that contribute to increased disease prevalence, hospitalization, and mortality. Recent advances in pharmacological approaches have significantly improved clinical outcomes for patients with vascular injury and HF. Nevertheless, there remains an unmet need to clarify the crucial role of nitric oxide/cyclic guanosine 3',5'-monophosphate (NO/cGMP) signalling in cardiac contraction and relaxation, to better identify the key mechanisms involved in the pathophysiology of myocardial dysfunction both with reduced (HFrEF) as well as preserved ejection fraction (HFpEF). Indeed, NO signalling plays a crucial role in cardiovascular homeostasis and its dysregulation induces a significant increase in oxidative and nitrosative stress, producing anatomical and physiological cardiac alterations that can lead to heart failure. The present review aims to examine the molecular mechanisms involved in the bioavailability of NO and its modulation of downstream pathways. In particular, we focus on the main therapeutic targets and emphasize the recent evidence of preclinical and clinical studies, describing the different emerging therapeutic strategies developed to counteract NO impaired signalling and cardiovascular disease (CVD) development.

The future of group 2 pulmonary hypertension: Exploring clinical trials and therapeutic targets

Pulmonary hypertension due to left heart disease (PH-LHD) or group 2 PH is the most common and lethal form of PH, occurring secondary to left ventricular systolic or diastolic heart failure (HF), left-sided valvular diseases, and congenital abnormalities. It is subdivided into isolated postcapillary PH (IpcPH) and combined pre- and post-capillary PH (CpcPH), with the latter sharing many similarities with group 1 PH. CpcPH is associated with worse outcomes and increased morbidity and mortality when compared to IpcPH. Although IpcPH can be improved by treatment of the underlying LHD, CpcPH is an incurable disease for which no specific treatment exists, likely due to the lack of understanding of its underlying mechanisms. Furthermore, drugs approved for PAH are not recommended for group 2 PH, as they are either ineffective or even deleterious. With this major unmet medical need, a better understanding of mechanisms and the identification of effective treatment strategies for this deadly condition are urgently needed. This review presents relevant background of the molecular mechanisms underlying PH-LHD that could translate into innovative therapeutic targets and explores novel targets currently being evaluated in clinical trials.

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.

A new perspective on NO pathway in sepsis and ADMA lowering as a potential therapeutic approach

The nitric oxide pathway plays a critical role in vascular homeostasis. Increased levels of systemic nitric oxide (NO) are observed in preclinical models of sepsis and endotoxemia. This has led to the postulation that vasodilation by inducible nitric oxide synthase (iNOS) generated NO may be a mechanism of hypotension in sepsis. However, contrary to the expected pharmacological action of a nitric oxide synthase (NOS) inhibitor, clinical studies with L-NAME produced adverse cardiac and pulmonary events, and higher mortality in sepsis patients. Thus, the potential adverse effects of NO in human sepsis and shock have not been fully established. In recent years, the emerging new understanding of the NO pathway has shown that an endogenously produced inhibitor of NOS, asymmetric dimethylarginine (ADMA), a host response to infection, may play an important role in the pathophysiology of sepsis as well as organ damage during ischemia–reperfusion. ADMA induces microvascular dysfunction, proinflammatory and prothrombotic state in endothelium, release of inflammatory cytokines, oxidative stress and mitochondrial dysfunction. High levels of ADMA exist in sepsis patients, which may produce adverse effects like those observed with L-NAME. Several studies have demonstrated the association of plasma ADMA levels with mortality in sepsis patients. Preclinical studies in sepsis and ischemia–reperfusion animal models have shown that lowering of ADMA reduced organ damage and improved survival. The clinical finding with L-NAME and the preclinical research on ADMA “bed to bench” suggest that ADMA lowering could be a potential therapeutic approach to attenuate progressive organ damage and mortality in sepsis. Testing of this approach is now feasible by using the pharmacological molecules that specifically lower ADMA.

Cognitive decline in heart failure: Biomolecular mechanisms and benefits of exercise

By definition, heart failure (HF) is a human pathological condition affecting the structure and function of all organs in the body, and the brain is not an exception to that. Failure of the heart to pump enough blood centrally and peripherally is at the foundation of HF patients' inability to attend even the most ordinary daily activities and progressive deterioration of their cognitive capacity. What is more, between heart and brain exists a bidirectional relationship that goes well beyond hemodynamics and concerns bioelectric and endocrine signaling. This increasingly consolidated evidence makes the scenario even more complex. Studies have mainly chased how HF impairs cognition without focusing much on preventive measures, notably cardio-cerebral health proxies. Here, we aim to provide a brief account of known and hypothetical factors that may explain how exercise can help obviate cognitive dysfunction associated with HF in its different forms. As we shall see, there is a stringent need for a deeper grasp of such mechanisms. Indeed, gaining this new knowledge will automatically shed new light on the inner workings of HF itself, thus resulting in more effective prevention and treatment of this escalating syndrome.

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

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

Evaluation of Asymmetric Dimethylarginine Serum Level and Left Ventricular Function by 2D Speckle Tracking Echocardiography in Children on Regular Hemodialysis

Cardiovascular disease is the leading cause of morbidity and mortality in children with chronic kidney disease. Asymmetric dimethylarginine (ADMA) is thought to be related to chronic kidney disease patients' adverse cardiovascular effects. Our study is to assess ADMA concentrations in children on hemodialysis (HD) as a marker of cardiovascular risk and detect the relation to the left ventricular (LV) function by traditional and speckled tracking echo. Forty children with end-stage renal disease on regular HD were enrolled in the study and selected from the nephrology HD unit of Al-Zahraa Hospital, Al-Azhar University. Another group of 40 healthy children matches age and sex with the patient's group as a control. ADMA serum level, traditional echo, and tissue Doppler imaging spackled tracking were performed to assess: LV functions for both groups in the same line with the routine laboratory investigations. Moreover, bioimpedance was assessed after the HD session. Children on regular HD have a significantly higher (ADMA) serum level compared to their controls; the median is (72.5 ng/mL) and (25 ng/mL), respectively (P = 0.001) and a significant increase in high-sensitivity C-reactive protein and the median is (3.6 ng/mL) and (2.5 ng/mL), respectively (P = 0.001). Moreover, conventional echo detects 27 (67.5%) patients out of 40 had an impaired LV function; meanwhile, 33 (82.5%) had a global LV strain (LV GLS) detected by 2D (Speckle echo), a negative correlation between LV ejection fraction with serum (urea, cholesterol, and triglyceride) and a positive correlation between ADMA and LV systolic diameter. LV GLS (Speckle echo) is negatively correlated with LV end-diastolic diameter, LV end-systolic diameter and positively correlated with LV inter ventricular septum in diastole and reduced average systolic velocity (ml). The sensitivity and specificity of (ADMA), high-sensitivity C-reactive protein (hs-CRP), traditional, and Speckle echo for early left ventricular (LV) dysfunction were 92.50, 92, and 67.50, 97 and 67.50, 90.00, and 80.00, 92, respectively. An ADMA emerges as a sensitive and specific marker for early LV dysfunction in children on hemodialysis (HD); drugs targeting ADMA isessential in the future direction after clinical approval, to avoid early LV changes, furthermore (Speckle echo) is superior to the traditional echo for early detection of LV changes in chronic kidney disease (CKD) children.

Circulating Hydrogen Sulfide (H2S) and Nitric Oxide (NO) Levels Are Significantly Reduced in HIV Patients Concomitant with Increased Oxidative Stress Biomarkers

Human immunodeficiency virus (HIV) attacks the immune system and weakens the ability to fight infections/disease. Furthermore, HIV infection confers approximately two-fold higher risk of cardiac events compared with the general population. The pathological mechanisms responsible for the increased incidence of cardiovascular disease in HIV patients are largely unknown. We hypothesized that increased oxidative stress and attenuated circulating levels of the cardioprotective gaseous signaling molecules, nitric oxide (NO), and hydrogen sulfide (H₂S) were involved in the cardiovascular pathobiology observed in HIV patients. Plasma samples from both HIV patients and age-matched normal subjects were used for all assays. Oxidative stress was determined by analyzing the levels of advanced oxidation protein products (AOPP) and H₂O₂. Antioxidant levels were determined by measuring the levels of trolox equivalent capacity. ADMA, hs-CRP, and IL-6 were determined by using ELISA. The levels of H₂S (free H₂S and sulfane sulfur) and NO₂ (nitrite) were determined in the plasma samples by using gas chromatography and HPLC, respectively. In the present study we observed a marked induction in the levels of oxidative stress and decreased antioxidant status in the plasma of HIV patients as compared with the controls. Circulating levels of the cardiovascular disease biomarkers: ADMA, hs-CRP (high-sensitivity C-reactive protein), and IL-6 were significantly increased in the circulatory system of HIV patients. The levels of both nitrite and H₂S/sulfane sulfur were significantly reduced in the plasma of HIV patients as compared with normal subjects. Our data demonstrate significant increases in circulating biomarkers of oxidative stress and cardiovascular (CV) in conjunction with decreased bioavailability of H₂S and NO in HIV patients. Diminished levels of these two cardioprotective gaseous signaling molecules may be involved in the pathogenesis of CV disease in the setting of HIV.

DDAH1 SNP rs480414 that protects against the development of pulmonary hypertension in bronchopulmonary dysplasia results in lower nitric oxide production in neonatal cord blood-derived lymphoblastoid cell lines

BACKGROUND

Bronchopulmonary dysplasia (BPD) is chronic lung disease of prematurity and pulmonary hypertension (PH) is a major contributor to morbidity and mortality in BPD patients. Nitric oxide (NO) is a vasodilator and apoptotic mediator made by NO synthase (NOS). NOS is inhibited by asymmetric dimethylarginine (ADMA), and dimethylarginine dimethylaminohydrolase (DDAH) hydrolyzes ADMA. Previously, in a BPD patient cohort, we identified single nucleotide polymorphism (SNP) DDAH1 rs480414 (G >  A) that was protective against developing PH. This study aims to determine functional consequences of the DDAH1 SNP in lymphoblastoid cell lines (LCLs) derived from neonatal cord blood. We tested the hypothesis that DDAH1 SNP (AA) results in DDAH1 gain of function, leading to greater NO-mediated apoptosis compared to DDAH1 wild-type (GG) in LCLs.

METHODS

LCLs were analyzed by Western blot (DDAH1, cleaved and total caspase-3 and -8, and β-actin), and RT-PCR (DDAH1, iNOS). Cell media assayed for nitrites with chemiluminescence NO analyzer, and conversion of ADMA to L-citrulline was measured by spectrophotometry.

RESULTS

LCLs with DDAH1 SNP had similar levels of DDAH1 protein and mRNA expression, as well as DDAH activity, compared to DDAH1 WT LCLs. There were also no changes in cleaved caspase-3 and -8 protein levels. LCLs with DDAH1 SNP had similar iNOS mRNA expression. Nitrite levels in media were lower for DDAH1 SNP LCLs compared to DDAH1 WT LCLs (p <  0.05).

CONCLUSION

Contrary to our hypothesis, we found that NO production was lower in DDAH1 SNP LCLs, indicative of a loss of function phenotype.

Effect of l-arginine on cardiac reverse remodeling and quality of life in patients with heart failure

BACKGROUND & AIMS

Heart failure (HF), as a major cardiac disease, is associated with considerable mortality, morbidities and poor quality of life. The aim of this study was to investigate the effect of l-arginine supplementation on cardiac outcomes and quality of life in patients with ischemic HF.

METHODS

This double-blind randomized controlled clinical trial was conducted in 50 patients with ischemic HF. Patients were randomly assigned to receive either 3 gr/d l-arginine or placebo, for 10 weeks. Cardiac function (based on echocardiography and six-minute walk test), blood pressure, and quality of life (based on the Minnesota living with heart failure questionnaire) were assessed.

RESULTS

The results showed significant improvements in ejection fraction (-6.5 ± 8.7 vs. -0.7 ± 7.8%, P = 0.037), left ventricular function (P = 0.043), diastolic dysfunction (P = 0.01) and marginally improvement in changes of left ventricular dimension during diastole (LVDd) (4 ± 6 vs. 0.3 ± 6.9 mm, P = 0.065) in the l-arginine compared to the placebo group. At the end of the study, physical aspect (5.7 ± 3.3 vs. 1.2 ± 6.1, P = 0.002) and total score (10 ± 6.7 vs. 4.1 ± 9.4, P = 0.011) of quality of life improved significantly in the l-arginine compared with the placebo group. Additionally, pre-to post-values of diastolic blood pressure, mean arterial pressure, LVDd, LV ejection fraction, left ventricular function, diastolic dysfunction as well as physical and total scores of quality of life improved significantly within the intervention, but not the placebo, group (all P < 0.05).

CONCLUSION

This study showed that 3 gr/d l-arginine supplementation for 10 weeks could improve cardiac recovery and function, and quality of life in patients with HF. This study was registered at the Iranian Clinical Trial Registration Center (www.irct.ir) with IRCT20170202032367N4 code.

The Importance of a New Cardiovascular Risk Factor - Asymmetric Dimethylarginine

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

Klotho gene improves oxidative stress injury after myocardial infarction

The aim of the present study was to investigate the effects and mechanisms of the Klotho gene in oxidative stress injury after myocardial infarction. Sprague-Dawley rats were divided into five groups (sham, model, pDC316, LY294002, and pDC316-Klotho). Subsequently, the superoxide dismutase (SOD), glutathione (GSH), and malondialdehyde (MDA) concentrations were measured in myocardial tissues. Additionally, pathological differences among the groups were evaluated using hematoxylin and eosin and Masson's trichrome staining. Apoptosis was assayed by terminal deoxynucleotidyl transferase 2'-deoxyuridine-5'-triphosphate nick end-labeling assay, evaluated Klotho protein expression by immunohistochemical assay, and assessed Nrf 2 and ARE protein expressions using western blotting assay. As compared with in the sham group, the SOD, MDA, and GSH concentrations were significantly deteriorated (P<0.001, respectively); cardiomyocyte apoptosis index values were significantly increased (P<0.001); Klotho protein expression was significantly depressed; and Nrf-2 and ARE protein expressions were significantly (P<0.001, respectively) in the model and pDC316 groups. However, with Klotho supplementation by pDC316 transfection, as compared with in the model group, the SOD, MDA, and GSH concentrations were significantly improved (P<0.001, respectively); the cardiomyocyte apoptosis index values were significantly suppressed (P<0.001); and the pathology was improved. Further, the Klotho protein expression of the pDC316-Klotho group was significantly upregulated and the Nrf-2 and ARE proteins expressions of the LY294002 and pDC316-Klotho groups were significantly suppressed. Klotho overexpression improved findings of oxidative stress injury after myocardial infarction.

Protective Effect of Epigallocatechin Gallate on Endothelial Disorders in Atherosclerosis

Healthy vascular endothelial cells regulate vascular tone and permeability, prevent vessel wall inflammation, enhance thromboresistance, and contribute to general vascular health. Furthermore, they perform important functions including the production of vasoactive substances such as nitric oxide (NO) and endothelium-derived hyperpolarizing factors, as well as the regulation of smooth muscle cell functions. Conversely, vascular endothelial dysfunction leads to atherosclerosis, thereby enhancing the risk of stroke, myocardial infarction, and other cardiovascular diseases (CVDs). Observational studies and randomized trials showed that green tea intake was inversely related to CVD risk. Furthermore, evidence indicates that epigallocatechin gallate (EGCG) found in green tea might exert a preventive effect against CVDs. EGCG acts as an antioxidant, inducing NO release and reducing endothelin-1 production in endothelial cells. EGCG enhances the bioavailability of normal NO by reducing levels of the endogenous NO inhibitor asymmetric dimethylarginine. Furthermore, it inhibits the enhanced expression of adhesion molecules such as vascular cell adhesion molecule-1 and intercellular adhesion molecule-1 and attenuates monocyte adhesion. In addition, EGCG prevents enhanced oxidative stress through the Nrf2/HO-1 pathway. These effects indicate that it might prevent the production of reactive oxygen species, inhibit inflammation, and reduce endothelial cell apoptosis during the initial stages of atherosclerosis. The current review summarizes recent research in this area and discusses novel findings regarding the protective effect of EGCG on endothelial dysfunction and CVDs in general.

Novel technique for the simultaneous isolation of cardiac fibroblasts and epicardial stromal cells from the infarcted murine heart

AIMS

Myocardial infarction (MI) leads to activation of cardiac fibroblasts (aCFs) and at the same time induces the formation of epicardium-derived cells at the heart surface. To discriminate between the two cell populations, we elaborated a fast and efficient protocol for the simultaneous isolation and characterization of aCFs and epicardial stromal cells (EpiSCs) from the infarcted mouse heart.

METHODS AND RESULTS

For the isolation of aCFs and EpiSCs, infarcted hearts (50 min ischaemia/reperfusion) were digested by perfusion with a collagenase-containing medium for only 8 min, while EpiSCs were enzymatically removed from the outside by applying mild shear forces via a motor driven device. Cardiac fibroblasts (CFs) isolated from unstressed hearts served as control. Viability of isolated cells was >90%. Purity of EpiSCs was confirmed by immunofluorescence staining and qPCR of various mesenchymal markers including Wilms-tumor-protein-1. Microarray analysis of CFs, aCFs, and EpiSCs on day 5 post-MI revealed a unique gene expression pattern in the EpiSC fraction, which was enriched for epithelial markers and epithelial to mesenchymal transition-related genes. Compared to aCFs, 336 significantly altered gene entities were identified in the EpiSC fraction. qPCR analysis showed high expression of Serpinb2, Cxcl13, Adora2b, and Il10 in EpiSCs relative to CFs and aCFs. Furthermore, microarray data identified Ddah1 and Cemip to be highly up-regulated in aCFs compared to CFs. Immunostaining of the infarcted heart revealed a unique distribution of Dermokine, Aquaporin-1, Cytokeratin, Lipocalin2, and Periostin within the epicardial cell layer.

CONCLUSIONS

We describe the simultaneous isolation of viable, purified fractions of aCFs and EpiSCs from the infarcted mouse heart. In this study, several differentially expressed markers for aCFs and EpiSCs were identified, underlining the importance of cell separation to study heterogeneity of stromal cells in the healing process after MI.

Crucial markers showing the risk of coronary artery disease in obesity: ADMA and neopterin

Background

Obesity is responsible for high morbidity and mortality, both in developed and developing countries. It is associated with many chronic and metabolic diseases. Asymmetric dimethylarginine (ADMA) has been demonstrated to be a biomarker of endothelial dysfunction in humans and increased ADMA associated with cardiovascular disease (CVD) risk has been reported in many states. Neopterin (NP) produced by monocytes/macrophages in response to stimulation by interferon-gamma (IFN-γ) is emphasized in recent findings. The current study aims to investigate ADMA and NP levels which may assume a role in guiding the early diagnosis of coronary artery disease in obesity.

Methods

This is an original research study in which ADMA and NP levels of 50 patients (25 male/25 female) diagnosed with obesity were compared with those of 30 healthy individuals (15 male/15 female) as control. The high-performance liquid chromatography (HPLC) method was used while determining parameters.

Results

ADMA and NP levels in obese individuals were found to be significantly higher than in those enrolled in the control. ADMA values were found to be higher in obese subjects (0.71±0.24 μmol/L) as compared with levels found in healthy subjects (0.58±0.16 μmol/L) (p<0.05). A significant increase of serum neopterin levels was found in obese subjects (8.8±3.5 μmol/L) as compared with controls (4.9±1.69 μmol/L) (p<0.05). Also, there was a strong positive correlation between NP and ADMA values in obese individuals (r=0.954).

Conclusions

Our study revealed that obese subjects have higher ADMA and neopterin levels. These results demonstrated that both ADMA and NP levels may be potential risk factors for coronary heart disease in obesity.

Mixture of MMP-2, MLC, and NOS Inhibitors Affects NO Metabolism and Protects Heart from Cardiac I/R Injury

Objectives

Coronary reperfusion procedure leads to ischemia/reperfusion injury of the heart (IRI). IRI arises from increased degradation of myosin light chains and increased activity of matrix metalloproteinase 2 (MMP-2). Increased production of toxic peroxynitrite (ONOO^-) during oxidative stress is a source of increased nitration/nitrosylation of contractile proteins, which enhance their degradation through MMP-2. Hence, an imbalance in nitric oxide (NO) metabolism along with oxidative stress is an important factor contributing to pathophysiology of cardiovascular disorders, including myocardial infarction. The aim of the current study was to provide an important insight into understanding the interaction of iNOS, eNOS, and ADMA during oxidative stress and to propose the beneficial therapy to modulate this interaction. Material and Methods. Pathogen-free Wistar rats were used in this study as a surrogate heart model ex vivo. Rat hearts perfused using the Langendorff method were subjected to global no-flow ischemia with or without administration of DOXY (1 µM), ML-7 (0.5 µM), and L-NAME (2 µM) mixture. Haemodynamic parameters of heart function, markers of I/R injury, tissue expression of iNOS, eNOS, and phospho-eNOS, asymmetric dimethylarginine, and NO production as well as MMP-2 activity were measured.

Results

Mechanical heart function and coronary flow (CF) were decreased in the hearts subjected to I/R. Treatment of the hearts with the tested mixture resulted in a recovery of mechanical function due to decreased activity of MMP-2. An infusion of Doxy, ML-7, and L-NAME mixture into I/R hearts decreased the expression of iNOS, eNOS, and phospho-eNOS and in consequence reduced ADMA expression. Decreased ADMA production led to enhanced NO synthesis and improvement of cardiac function at 85% of aerobic control.

Conclusions

Synergistic effect of the multidrug therapy with the subthreshold doses allows addressing a few pathways of I/R injury simultaneously to achieve protection of cardiac function during I/R.

Uremic Toxin-Targeting as a Therapeutic Strategy for Preventing Cardiorenal Syndrome

Chronic kidney disease (CKD) is a global health problem. CKD patients are at high risk of developing cardiovascular disease (CVD), including coronary artery disease, heart failure and stroke. Several factors invoke a vicious cycle of CKD and CVD, which is referred as to "cardiorenal syndrome". Among these factors, the compounds retained through loss of renal excretion play a pathological role in causing atherosclerosis and CVD. These compounds have been broadly classified as uremic toxins because of their accumulation with declining renal function and cytotoxicity. The major uremic toxins contributing to CVD are asymmetric dimethylarginine (ADMA), advanced glycation endproducts (AGE), and trimethyl amine N-oxide (TMAO). ADMA is linked to CVD through regulation of nitric oxide, reactive oxygen species, and renal anemia. AGE not only directly accumulates in the heart and kidney, but interacts with the receptor for AGE (RAGE), leading to cell damage in CVD. TMAO correlates with a high prevalence of CVD and promotes organ fibrosis by itself. The levels of these and other uremic toxins rise with worsening CKD, inducing multiplicative damage in the heart and kidney. Therefore, a better understanding of uremic toxins has great clinical importance for preventing cardiorenal syndrome. This review highlights the molecular mechanism by which these uremic toxins are implicated in CVD and suggests the possible mutual relationship between them.

Piper sarmentosum Promotes Endothelial Nitric Oxide Production by Reducing Asymmetric Dimethylarginine in Tumor Necrosis Factor-α-Induced Human Umbilical Vein Endothelial Cells

Asymmetric dimethylarginine (ADMA) is an endogenous inhibitor of endothelial nitric oxide synthase (eNOS). ADMA is degraded by dimethylarginine dimethylaminohydrolase (DDAH). Elevated levels of ADMA lead to reduction in nitric oxide (NO) production, which is linked to endothelial dysfunction and atherosclerosis. Piper sarmentosum is an herb that has shown stimulation on endothelial NO production by increasing both expression and activity of eNOS. Thus, this study determined whether the positive effect of P. sarmentosum on NO production is related to its modulation on the DDAH-ADMA pathway in cultured human umbilical vein endothelial cells (HUVEC) exposed to tumor necrosis factor-α (TNF-α). HUVEC were divided into four groups: control, treatment with 250 µg/ml of aqueous extract of P. sarmentosum leaves (AEPS), treatment with 30 ng/ml of TNF-α, and concomitant treatment with AEPS and TNF-α for 24 h. After treatments, HUVEC were collected to measure DDAH1 messenger RNA (mRNA) expression using quantitative real-time polymerase chain reaction. DDAH1 protein level was measured using enzyme-linked immunosorbent assay (ELISA), and DDAH enzyme activity was measured using colorimetric assay. ADMA concentration was measured using ELISA, and NO level was measured using Griess assay. Compared to control, TNF-α-treated HUVEC showed reduction in DDAH1 mRNA expression (P < 0.05), DDAH1 protein level (P < 0.01), and DDAH activity (P < 0.05). Treatment with AEPS successfully increased DDAH1 mRNA expression (P < 0.05), DDAH1 protein level (P < 0.01), and DDAH activity (P < 0.05) in TNF-α-treated HUVEC. Treatment with TNF-α caused an increase in ADMA level (P < 0.01) and a decrease in endothelial NO production (P < 0.001). Whereas treatment with AEPS was able to reduce ADMA level (P < 0.01) and restore NO (P < 0.001) in TNF-α-treated HUVEC. The results suggested that AEPS promotes endothelial NO production by stimulating DDAH activity and thus reducing ADMA level in TNF-α-treated HUVEC.

Isolevuglandin scavenger attenuates pressure overload-induced cardiac oxidative stress, cardiac hypertrophy, heart failure and lung remodeling

Increased levels of reactive isolevuglandins (IsoLGs) are associated with vascular inflammation and hypertension, two important factors affect heart failure (HF) development. The role of IsoLGs in HF development is unknown. Here we studied the role of IsoLG scavenger 2-hydroxybenzylamine (2-HOBA) in transverse aortic constriction (TAC) induced heart failure. We observed that TAC caused a significant increase of IsoLG protein adducts in cardiac and lung tissues in mice. Both IsoLG scavenger 2-hydroxybenzylamine (2-HOBA) and its less reactive isomer 4-hydroxybenzylamine (4-HOBA) significantly attenuated the left ventricular (LV) and lung IsoLGs in mice after TAC. 2-HOBA and 4-HOBA attenuated TAC-induced LV hypertrophy, heart failure, and the increase of lung weight in mice, and also improved TAC-induced LV dysfunction. Moreover, both 2-HOBA and 4-HOBA effectively attenuated LV cardiomyocyte hypertrophy, lung inflammation, lung fibrosis. These findings suggest that methods to reduce IsoLGs may be useful for HF therapy.

Association of Asymmetric Dimethylarginine and Diastolic Dysfunction in Patients with Hypertrophic Cardiomyopathy

Despite genetic heterogeneity, early manifestation of diastolic dysfunction (DD) is common in hypertrophic cardiomyopathy (HCM). Nitric oxide (NO) may contribute to myocardial relaxation. NO synthases (NOS) use l-arginine (Arg) as a substrate, as asymmetric dimethylarginine (ADMA) is a direct endogenous inhibitor of NOS. This study aimed to analyze the association of Arg and its derivates, i.e., l-homoarginine (hArg), ADMA and symmetric dimethylarginine (SDMA), with DD in HCM patients. In 215 HCM patients (mean age 54 ± 15 years, 58% male) transmitral and mitral annulus velocities were echocardiographically analyzed. Plasma concentrations of Arg derivatives were measured by liquid chromatography tandem-mass spectrometry. In 143 (70%) patients suffering from DD, ADMA showed the strongest association with DD (0.66 ± 0.16, 0.72 ± 0.24, and 0.76 ± 0.26 µmol/L, p < 0.01 for trend). In linear regression analyses, positive association per standard deviation increase of ADMA was found with E-wave (beta coefficient (95% confidence interval): 4.72 (0.43–9.01); p < 0.05) and mean E/E’ (1.76 (0.73–2.79) p < 0.001). Associations were adjusted for age, sex, body mass index (BMI), diabetes mellitus, coronary artery disease, and arterial hypertension. Elevated ADMA is associated with the severity of DD in HCM. Higher ADMA level might lead to decreased NO production and thus an impaired myocardial relaxation pattern.

Profound Increase of Lung Airway Resistance in Heart Failure: a Potential Important Contributor for Dyspnea

Dyspnea is a major symptom of heart failure (HF). Here, we have studied the lung remodeling and airway resistance in HF mice. We demonstrated that aortic banding-induced HF caused a dramatic decrease of lung compliance and an increase of lung airway resistance. The decrease of lung compliance was correlated with the increased lung weight in a linear fashion (γ² = 0.824). An HF-induced increase of lung airway resistance and a decrease of lung compliance were almost identical in anesthetized mice and in the isolated lungs from these mice. HF caused profound lung fibrosis in mice with increased lung weight. Moreover, HF patients of NYHA class III-IV showed increased lung density as revealed by high-resolution CT scanning. These data indicate that lung compliance and lung airway resistance may be useful in determining lung remodeling after HF, and lung structure changes may contribute to dyspnea in HF.

Association between asymmetric dimethylarginine serum levels and left ventricular longitudinal deformation in patients with normal ejection fractions: a two-dimensional speckle-tracking echocardiography examination

OBJECTIVES

Nitric oxide is an endogenous substance that preserves the myocardial function in patients with heart failure. Asymmetric dimethylarginine (ADMA) is a competitive inhibitor of endogenous nitric oxide synthase. We sought to explore the association between the left ventricular (LV) function as assessed with two-dimensional echocardiography and the serum level of ADMA in nondiabetic patients without significant coronary artery disease.

PATIENTS AND METHODS

Eighty-seven consecutive patients with normal LV ejection fractions were included in this cross-sectional study. The ADMA serum level was measured, and the longitudinal deformation indices of the LV myocardium were evaluated using two-dimensional speckle-tracking echocardiography (2DSTE).

RESULTS

The systolic strain, the systolic strain rate, and the early and late diastolic strain rates as evaluated with 2DSTE were not statistically significantly different between the patients with normal ADMA serum levels and those with increased ADMA serum levels. The two study groups were also not significantly different in terms of the systolic and diastolic myocardial velocities obtained with tissue Doppler.

CONCLUSION

Our findings showed no statistically significant correlations between the serum ADMA level and the 2DSTE-derived indices of the longitudinal deformation of the LV myocardium in our nondiabetic patients without significant coronary artery stenosis and with normal LV ejection fractions.

Asymmetrical Dimethylarginine Levels in Hepatitis B Virus-Positive Patients

BACKGROUND

High asymmetrical dimethylarginine (ADMA) levels have been associated with endothelial dysfunction and contribute to the development of several diseases. However, data on the relationship between hepatitis B virus (HBV) and ADMA are limited. The aim of our study was to explore the relationship between ADMA and HBV by comparing the ADMA levels in patients with chronic active hepatitis B (CHB), inactive HBV carriers (carriers), and healthy volunteers (controls).

METHODS

The participants were divided into three groups: 90 patients with CHB, 90 HBV carriers, and 90 controls. Serum ADMA levels were quantified using an ELISA kit (Cusabio, Wuhan, China). The data were analyzed using an ANOVA or the Kruskal-Wallis test as appropriate, with P<0.05 considered significant.

RESULTS

Serum ADMA levels were significantly higher in patients with CHB (228.35±91.10 ng/mL) than in HBV carriers (207.80±75.80 ng/mL) and controls (207.61±89.10 ng/mL) (P=0.049). The clinical scores of the patients were positively correlated with ADMA levels.

CONCLUSIONS

The elevated serum ADMA levels in patients with CHB confirm that HBV plays a role in vasculitis. Further investigation of the mechanisms contributing to the high levels of ADMA in CHB may contribute toward development of new treatment modalities.

Asymmetric dimethylarginine (ADMA) as an important risk factor for the increased cardiovascular diseases and heart failure in chronic kidney disease

Patients with chronic kidney disease have an increased cardiovascular morbidity and mortality. It has been recognized that the traditional cardiovascular risk factors could only partially explain the increased cardiovascular morbidity and mortality in patients with chronic kidney disease. Asymmetric dimethylarginine (ADMA) and N-monomethy l-arginine (L-NMMA) are endogenous inhibitors of nitric oxide synthases that attenuate nitric oxide production and enhance reactive oxidative specie generation. Increased plasma ADMA and/or L-NMMA are strong and independent risk factor for chronic kidney disease, and various cardiovascular diseases such as hypertension, coronary artery disease, atherosclerosis, diabetes, and heart failure. Both ADMA and L-NMMA are also eliminated from the body through either degradation by dimethylarginine dimethylaminohydrolase-1 (DDAH1) or urine excretion. This short review will exam the literature of ADMA and L-NMMA degradation and urine excretion, and the role of chronic kidney diseases in ADMA and L-NMMA accumulation and the increased cardiovascular disease risk. Based on all available data, it appears that the increased cardiovascular morbidity in chronic kidney disease may relate to the dramatic increase of systemic ADMA and L-NMMA after kidney failure.

Serum concentrations of asymmetric and symmetric dimethylarginine are associated with mortality in acute heart failure patients

BACKGROUND

Serum concentrations of asymmetric (ADMA) and symmetric (SDMA) dimethylarginine are established predictors of total and cardiovascular mortality. However, the predictive capacity of ADMA and SDMA for hospital and 3-months mortality of patients with acute heart failure (AHF) is unknown.

METHODS & RESULTS

Out of 152 included AHF patients, 79 (52%) were female, and the mean patient age was 75.2 ± 10.3 years. Hospital and three-month mortality rates were 14.5% and 27.4%, respectively. Serum ADMA and SDMA levels at admission, determined by reversed phase high performance liquid chromatography, were higher in patients having at least one of the three signs implying venous volume overload (enlarged liver, ascites, peripheral edema), a consequence of right-sided heart failure, compared to patients without those signs. Univariable logistic regression analyses revealed a significant positive association of ADMA and SDMA concentrations with hospital mortality [odds ratio (OR) and 95% confidence interval (CI) per standard deviation (SD) increase: 2.22 (1.37-3.79), p = 0.002, and 2.04 (1.34-3.18), p = 0.001, respectively], and 3-months mortality [2.06 (1.36-3.26), p = 0.001, and 2.52 (1.67-4.04), p < 0.001, respectively]. These associations remained significant after adjusting for age, sex, mean arterial pressure, low-density lipoprotein cholesterol, glomerular filtration rate, and N-terminal pro-brain natriuretic peptide.

CONCLUSIONS

We conclude that ADMA and SDMA concentrations are associated with hospital and 3-month mortality and are increased by venous volume overload in AHF patients.

Ammonia Reduces Intracellular Asymmetric Dimethylarginine in Cultured Astrocytes Stimulating Its y⁺LAT2 Carrier-Mediated Loss

Previously we had shown that ammonia stimulates nitric oxide (NO) synthesis in astrocytes by increasing the uptake of the precursor amino acid, arginine via the heteromeric arginine/glutamine transporter y⁺LAT2. Ammonia also increases the concentration in the brain of the endogenous inhibitor of nitric oxide synthases (NOS), asymmetric dimethylarginine (ADMA), but distribution of ADMA surplus between the intraastrocytic and extracellular compartments of the brain has not been studied. Here we tested the hypothesis that ammonia modulates the distribution of ADMA and its analog symmetric dimethylarginine (SDMA) between the two compartments of the brain by competition with arginine for the y⁺LAT2 transporter. In extension of the hypothesis we analyzed the ADMA/Arg interaction in endothelial cells forming the blood-brain barrier. We measured by high-performance liquid chromatography (HPLC) and mass spectrometry (MS) technique the concentration of arginine, ADMA and SDMA in cultured cortical astrocytes and in a rat brain endothelial cell line (RBE-4) treated with ammonia and the effect of silencing the expression of a gene coding y⁺LAT2. We also tested the expression of ADMA metabolism enzymes: protein arginine methyltransferase (PRMT) and dimethylarginine dimethyl aminohydrolase (DDAH) and arginine uptake to astrocytes. Treatment for 48 h with 5 mM ammonia led to an almost 50% reduction of ADMA and SDMA concentration in both cell types, and the effect in astrocytes was substantially attenuated by silencing of the Slc7a6 gene. Moreover, the y⁺LAT2-dependent component of ammonia-evoked arginine uptake in astrocytes was reduced in the presence of ADMA in the medium. Our results suggest that increased ADMA efflux mediated by upregulated y⁺LAT2 may be a mechanism by which ammonia interferes with intra-astrocytic (and possibly intra-endothelial cell) ADMA content and subsequently, NO synthesis in both cell types.

Cardiomyocyte dimethylarginine dimethylaminohydrolase-1 (DDAH1) plays an important role in attenuating ventricular hypertrophy and dysfunction

Asymmetric dimethylarginine (ADMA) is an endogenous inhibitor of nitric oxide synthases that limits nitric oxide bioavailability. Dimethylarginine dimethylaminohydrolase-1 (DDAH1) exerts a critical role for ADMA degradation and plays an important role in NO signaling. In the heart, DDAH1 is observed in endothelial cells and in the sarcolemma of cardiomyocytes. While NO signaling is important for cardiac adaptation to stress, DDAH1 impact on cardiomyocyte homeostasis is not clear. Here we used the MerCreMer-LoxP model to specifically disrupt cardiomyocyte DDAH1 expression in adult mice to determine the physiological impact of cardiomyocyte DDAH1 under basal conditions and during hypertrophic stress imposed by transverse aortic constriction (TAC). Under control conditions, cardiomyocyte-specific DDAH1 knockout (cDDAH KO) had no detectable effect on plasma ADMA and left ventricular (LV) hypertrophy or function in adult or aging mice. In response to TAC, DDAH1 levels were elevated 2.5-fold in WT mice, which exhibited no change in LV or plasma ADMA content and moderate LV hypertrophy and LV dysfunction. In contrast, cDDAH1 KO mice exposed to TAC showed no increase in LV DDAH1 expression, slightly increased LV tissue ADMA levels, no increase in plasma ADMA, but significantly exacerbated LV hypertrophy, fibrosis, nitrotyrosine production, and LV dysfunction. These findings indicate cardiomyocyte DDAH1 activity is dispensable for cardiac function under basal conditions, but plays an important role in attenuating cardiac hypertrophy and ventricular remodeling under stress conditions, possibly through locally confined regulation of subcellular ADMA and NO signaling.

Arginine-Nitric Oxide Metabolites and Cardiac Dysfunction in Patients With Breast Cancer

BACKGROUND

Oxidative/nitrosative stress and endothelial dysfunction are hypothesized to be central to cancer therapeutics-related cardiac dysfunction (CTRCD). However, the relationship between circulating arginine-nitric oxide (NO) metabolites and CTRCD remains unstudied.

OBJECTIVES

This study sought to examine the relationship between arginine-NO metabolites and CTRCD in a prospective cohort of 170 breast cancer patients treated with doxorubicin with or without trastuzumab.

METHODS

Plasma levels of arginine, citrulline, ornithine, asymmetric dimethylarginine (ADMA), symmetric dimethylarginine (SDMA), and N-monomethylarginine (MMA) were quantified at baseline, 1 month, and 2 months after doxorubicin initiation. Determinants of baseline biomarker levels were identified using multivariable linear regression, and Cox regression defined the association between baseline levels and 1- or 2-month biomarker changes and CTRCD rate in 139 participants with quantitated echocardiograms at all time points.

RESULTS

Age, hypertension, body mass index, and African-American race were independently associated with ≥1 of baseline citrulline, ADMA, SDMA, and MMA levels. Decreases in arginine and citrulline and increases in ADMA were observed at 1 and 2 months (all p < 0.05). Overall, 32 participants experienced CTRCD over a maximum follow-up of 5.4 years. Hazard ratios for ADMA and MMA at 2 months were 3.33 (95% confidence interval [CI]: 1.12 to 9.96) and 2.70 (95% CI: 1.35 to 5.41), respectively, and 0.78 (95% CI: 0.64 to 0.97) for arginine at 1 month.

CONCLUSIONS

In breast cancer patients undergoing doxorubicin therapy, early alterations in arginine-NO metabolite levels occurred, and early biomarker changes were associated with a greater CTRCD rate. Our findings highlight the potential mechanistic and translational relevance of this pathway to CTRCD.

Regulation of c-Jun N-Terminal Protein Kinase (JNK) Pathway in Apoptosis of Endothelial Outgrowth Cells Induced by Asymmetric Dimethylarginine

BACKGROUND Endothelial outgrowth cells (EOCs) are terminal endothelial progenitor cells (EPCs). Asymmetric dimethylarginine (ADMA) has been identified as a novel risk factor for cardiovascular diseases. Our aim in the present study was to investigate the effect of regulation of asymmetric dimethylarginine (ADMA) on EOCs apoptosis and to explore the underlining mechanisms of c-Jun N-terminal protein kinase (JNK) pathway in the process. MATERIAL AND METHODS EOCs were harvested from umbilical cord blood and obtained by using density gradient centrifugation and adhesive culture methods. Endothelial characteristics were identified by immunohistochemistry and fluorescence staining. EOCs were treated with different concentrations of ADMA and detected by flow cytometry. After JNK specific inhibitor (SP600125) was added, EOCs apoptosis protein expressions were measured by Western blot analysis. Proliferation, migration, and vascularization were detected by CCK-8 assay, wound healing assay, and tube-like formation assay, respectively. RESULTS EOCs were successfully extracted from umbilical cord blood and different concentrations of ADMA aggravated EOCs apoptosis. ADMA distinctly activates the phosphorylation activity of JNK. Supplementation of JNK-specific inhibitor (SP600125) decreased expression of Bax and cleaved caspase 3/9, and alleviated ADMA-induced apoptosis. SP600125 also promoted angiogenesis viability. CONCLUSIONS The JNK pathway participates in the apoptosis-promoting process of EOCs, and targeted inhibition of the JNK pathway can alleviate ADMA-induced injury, which I s the potential underlying mechanism of vascular endothelium injury in ischemic stroke.

The asymmetric dimethylarginine-mediated inhibition of nitric oxide in the rostral ventrolateral medulla contributes to regulation of blood pressure in hypertensive rats

Nitric oxide (NO) contributes to the central control of cardiovascular activity. The rostral ventrolateral medulla (RVLM) has been recognized as a pivotal region for maintaining basal blood pressure (BP) and sympathetic tone. It is reported that asymmetric dimethylarginine (ADMA), characterized as a cardiovascular risk marker, is an endogenous inhibitor of nitric oxide synthesis. The present was designed to determine the role of ADMA in the RVLM in the central control of BP in hypertensive rats. In Sprague Dawley (SD) rats, microinjection of ADMA into the RVLM dose-dependently increased BP, heart rate (HR), and renal sympathetic never activity (RSNA), but also reduced total NO production in the RVLM. In central angiotensin II (Ang II)-induced hypertensive rats and spontaneously hypertensive rat (SHR), the level of ADMA in the RVLM was increased and total NO production was decreased significantly, compared with SD rats treated vehicle infusion and WKY rats, respectively. These hypertensive rats also showed an increased protein level of protein arginine methyltransferases1 (PRMT1, which generates ADMA) and a decreased expression level of dimethylarginine dimethylaminohydrolases 1 (DDAH1, which degrades ADMA) in the RVLM. Furthermore, increased AMDA content and PRMT1 expression, and decreased levels of total NO production and DDAH1 expression in the RVLM in SHR were blunted by intracisternal infusion of the angiotensin II type 1 receptor (AT1R) blocker losartan. The current data indicate that the ADMA-mediated NO inhibition in the RVLM plays a critical role in involving in the central regulation of BP in hypertension, which may be associated with increased Ang II.

Associations of Exhaled Carbon Monoxide and Fractional Exhaled Nitric Oxide with Metabolic Syndrome: A Cohort Study

Exhaled carbon monoxide (eCO) and fractional exhaled nitric oxide (FeNO) could reflect underlying inflammatory and oxidative stresses, which play important roles in pathogenetic pathways of metabolic syndrome (MetS). However, epidemiologic evidence was limited. We conducted a study in Wuhan-Zhuhai (WHZH) cohort of 3649 community participants to investigate the association between eCO, FeNO and MetS in both cross-sectional and prospective ways. The results showed that higher eCO and FeNO were associated cross-sectionally with a higher prevalence of MetS. The multivariable-adjusted odds ratios for MetS at baseline were 1.22 (95% confidence interval [CI]: 1.11 to 1.35) associated with per log eCO and 1.14 (95% CI: 1.00 to 1.30) associated with per log FeNO. During a follow-up of 3 years, 358/2181 new developed MetS cases were identified. Compared with lowest quartile of eCO and FeNO, the multivariable-adjusted risk ratios (95% CI) for MetS were 1.48 (1.06 to 2.06) related to the highest quartile of eCO. These findings remained consistent across sex but not smoking status, eCO was only associated with MetS in non-smokers when stratified by smoking status. In conclusion, our study demonstrated that eCO and FeNO were independently and positively associated with the prevalence of MetS cross-sectionally, while only eCO was positively related with the incidence of MetS prospectively.