Asymmetric Dimethylarginine Concentrations Research Articles

Increased circulating levels of standardized inflammatory and endothelial dysfunction biomarkers in patients with myocardial infarction with nonobstructive coronary arteries

Abstract Introduction Around 10% of patients with acute myocardial infarction (AMI) present with nonobstructive coronary arteries (MINOCA), for which the underlying pathophysiology is often uncertain. Our aim was to evaluate inflammatory burden and endothelial dysfunction in MINOCA patients by assessing biomarkers in both acute and stable phases. Methods An analytical and observational study at a University Hospital involving 166 MI patients admitted over the past 3years. Following ESC guidelines, patients were categorized into MINOCA or myocardial infarction with significant coronary artery disease (MI-CAD) groups. Circulating levels of inflammatory biomarkers (interleukin-6(IL-6), tumor necrosis factor-α(TNF-α) and high-sensitivity C-reactive protein(hs-CRP)) and of endothelial dysfunction (asymmetric dimethylarginine (ADMA)) were measured in 44 MINOCA patients and 122 MI-CAD patients at acute phase (admission and discharge) and stable phase (2months after MI). As biomarker levels may vary with MI size, each value was standardized by dividing it by the peak troponin, resulting in a biomarker/troponinT ratio. We evaluated the effects of standardized (SB) and non-standardized (NSB) biomarker values using a multivariate regression model adjusted for age and sex. Results We analyzed 166 patients (median age:68 years, 70% males). MI-CAD patients had higher peak high-sensitive troponinT (hs-TnT) levels upon admission compared to those with MINOCA (1491ng/L vs 247ng/L,p<0.001),likely due to larger infarctions generating higher levels of inflammation. When examining the association between infarct size, as measured by peak hs-TnT values, and biomarker levels, we observed a significant dose-response relationship for hs-CRP at admission (βcoefficient 0.16 [95%CI,0.02-0.29],p0.02) and IL-6 at admission (βcoefficient 0.15 [95%CI,0.04-0.27],p0.01). Significant positive associations were found between MINOCA and all SBs, both during the acute phase and in follow-up. During the acute phase ORs ranged from 1.35to2.7 (p<0.05) for inflammatory biomarkers and from 2.34 to 2.76 (p<0.01) for ADMA. In the stable phase ORs ranged from 1.49to3.06 (p<0.05) for inflammatory biomarkers, and OR was 2.79(p<0.01) for ADMA (Figure 1). In contrast, none of the NSBs were associated with MINOCA. Regarding temporal biomarker changes, during the acute phase of MI and 2 months post-event, both MINOCA and MI-CAD patients showed similar trends. However, MINOCA patients consistently maintained elevated inflammatory activity and ADMA concentrations only when biomarkers were standardized by infarct size (Figure 2). Conclusions Higher levels of SBs were consistently associated with MINOCA, both during the acute phase of the event and in follow-up, compared to MI-CAD. Consequently, this study suggests that the inflammatory burden, measured by heightened levels of standardized inflammatory biomarkers, and endothelial dysfunction, as measured by ADMA, may play a role in the pathophysiology of MINOCA.Boxplots for SBs at three time points.Temporal changes in biomarker levels.

E-selectin and asymmetric dimethylarginine plasma levels in adult cyanotic congenital heart disease patients: relation to biochemical parameters, vascular function, and clinical status.

Abstract Background and Aim Patients with cyanosis secondary to congenital heart disease (CHD) are characterized by erythrocytosis and increased blood viscosity, which contributes to endothelial dysfunction, increased arterial stiffness, and impaired vascular function, which may affect the final clinical presentation. Asymmetric dimethylarginine (ADMA) and e-selectin (e-sel) are valuable biomarkers for prognosis of endocardial dysfunction and vascular damage. Their concentration levels in blood serum have the potential to be a rapid and easily accessible tool that reflects the severity of the disease. We aimed to assess e-sel and ADMA levels, their relationship with clinical status, as well as endothelial and vascular function. Methods A cross-sectional study including 36 adult CHD cyanotic patients [(17 males)(42.3 +/- 16.3 years)] with arterial blood oxygen saturation less than 92% and 20 healthy controls [(10 males)( 38.2 +/- 8.5 years)] was performed. All patients underwent clinical examination, blood testing, and cardiopulmonary tests. Endothelial function was assessed using intima-media thickness and flow-mediated dilatation (FMD). Vascular function using applanation tonometry methods was completed while considering aortic systolic pressure, aortic pulse pressure (AoPP), augmentation pressure (AP), augmentation index (AI), pulse pressure amplification (PPampl), and pulse wave velocity (PWV). Results Concentrations of e-sel and ADMA were significantly higher in patients with CHD than in controls (56.3 ± 13.6 ng/mL vs. 15.5 +/- 8.6 ng/mL, p<0.001) and (1.48 ± 0.48 ng/mL vs. 0.46 ± 0.1 ng/mL, p<0.001) respectively. E-sel levels correlated with gender, blood oxygen saturation, red blood cell, hemoglobin concentration, hematocrit, augmentation pressure, forced expiratory one second volume, forced vital capacity, and oxygen uptake. ADMA levels were found to correlate with age only. Conclusions E-sel level, unlike ADMA concentration, reflects the degree of severity of erythrocytosis and hypoxia and, thus, the physical status of patients with cyanotic CHD. E-selectin predicts increased augmentation pressure.Figure 1.A) ROC analysis for e-selectin

Serum concentration of asymmetric dimethylarginine, inflammatory markers and disease activity in relation with the components of metabolic syndrome in patients with spondyloarthritis

Serum concentration of asymmetric dimethylarginine, inflammatory markers and disease activity in relation with the components of metabolic syndrome in patients with spondyloarthritis

E-Selectin and Asymmetric Dimethylarginine Levels in Adult Cyanotic Congenital Heart Disease: Their Relation to Biochemical Parameters, Vascular Function, and Clinical Status.

Background and Aim: Patients with cyanosis secondary to congenital heart disease (CHD) are characterized by erythrocytosis and increased blood viscosity, which contribute to endothelial dysfunction, increased arterial stiffness, and impaired vascular function, which may affect the final clinical presentation. Asymmetric dimethylarginine (ADMA) and e-selectin (e-sel) are valuable biomarkers for endothelial and vascular dysfunction. Their concentration levels in blood serum have the potential to be an accessible tool that reflects the severity of the disease. We aimed to assess e-sel and ADMA levels and their relationship with the clinical status and endothelial and vascular function. Methods: A cross-sectional study, including 36 adult CHD cyanotic patients [(17 males) (42.3 ± 16.3 years)] with an arterial blood oxygen saturation less than 92% and 20 healthy controls [(10 males) (38.2 ± 8.5 years)], was performed. All the patients underwent a clinical examination, blood testing, and cardiopulmonary tests. Their endothelial function was assessed using the intima media thickness and flow-mediated dilatation. Vascular function, using applanation tonometry methods, was determined using the aortic systolic pressure, aortic pulse pressure, augmentation pressure, augmentation index, pulse pressure amplification, and pulse wave velocity. Results: The concentrations of e-sel and ADMA were significantly higher in the patients with CHD. The E-sel levels correlated positively with red blood cells, hemoglobin concentration, hematocrit, and augmentation pressure; they correlated negatively with blood oxygen saturation, the forced expiratory one-second volume, forced vital capacity, and oxygen uptake. The ADMA levels were found to correlate only with age. Conclusions: The E-sel level, unlike ADMA concentration, reflects the severity of erythrocytosis and hypoxia and, thus, the physical status of patients with cyanotic CHD.

Changes in nitric oxide inhibitors and mortality in critically ill patients: a cohort study

BackgroundOptimal balance between macro- and microcirculation in critically ill patients is crucial for ensuring optimal organ perfusion. Nitric oxide (NO) is a regulator of vascular hemostasis and tone. The availability of NO is controlled by asymmetric dimethylarginine (ADMA), symmetric dimethylarginine (SDMA), and the availability of the NO substrates arginine and homoarginine. We investigated the changes in plasma concentrations of ADMA, SDMA, arginine, and homoarginine days 1–5 of intensive care unit (ICU) admission and the association between the change in concentration days 1–3 and 30-day all-cause mortality.MethodsSingle-center cohort study of adult critically ill patients from the ICU at Copenhagen University Hospital – North Zealand. ADMA, SDMA, arginine, and homoarginine (NO-biomarkers) were measured on days 1–5. Initially, we determined the changes in NO-biomarkers days 1–5 with linear mixed models, and subsequently how the changes in NO-biomarkers days 1–3 were associated with 30-day all-cause mortality. Post-hoc we analyzed the association between plasma concentration at admission and 30-day all-cause mortality.ResultsIn total 567 out of 577 patients had plasma samples from days 1–5. Plasma concentrations of ADMA and arginine increased from days 1–5. SDMA concentrations increased from days 1–2, followed by a decrease from days 2–5. Concentrations of homoarginine did not change from days 1–3 but slightly increased from days 3–5. In total 512 patients were alive 3 days after ICU admission. Among these patients, a daily twofold increase in ADMA concentration from days 1–3 was associated with decreased mortality in multivariate analysis (HR 0.45; 95% CI 0.21–0.98; p = 0.046). An increase in SDMA, arginine, or homoarginine was not associated with mortality. Post-hoc we found that a twofold increase in ADMA or SDMA concentrations at admission was associated with mortality (HR 1.78; 95% CI 1.24–2.57; p = 0.0025, and HR 1.41; 95% CI 1.05–1.90; p = 0.024, respectively).ConclusionsIncreasing ADMA concentrations on days 1–3 are inversely associated with mortality, however not with the same strength as high ADMA or SDMA concentrations at admission. We suggest that admission concentrations are the focus of future research on ADMA and SDMA as predictors of mortality or potential therapeutical targets in ICU patients.

Asymmetric Dimethylarginine (ADMA) in Cardiovascular Disease, Cardiac Ischemia/reperfusion Injury, and Ischemic Non-obstructive Coronary Artery Disease: Biochemical and Pharmacological Implications

: Several studies have shown that high plasma concentrations of asymmetric dimethylarginine (ADMA), a known endogenous competitive inhibitor of endothelial nitric oxide synthase (eNOS), correlate with the severity of coronary artery disease (CAD), with worsening of cardiac ischemia/reperfusion (I/R) injury and coronary atherosclerosis. It is believed that it may be an important risk factor for myocardial infarction. ADMA, when in high concentrations, can determine a significant decrease in the synthesis and bioavailability of NO (Nitric oxide) and therefore alter the mechanisms of regulation of coronary vasodilation and vasomotor function of epicardial coronary arteries. Higher serum ADMA concentration is associated with worsening of post-ischemic remodeling since coronary angiogenesis, vasculogenesis, and collateral coronary growth are seriously impaired. In addition, there are reasons to believe that elevated plasma ADMA levels are related to the development of diseases affecting coronary microcirculation, such as ischemic non-obstructive coronary artery disease (INOCA). With the aim of providing the pharmacologist engaged in the design and discovery of new ADMA-lowering drugs with a complete examination of the subject, in this review, we discuss the most important studies related to the correlations between serum ADMA levels and cardiovascular diseases mentioned above. In addition, we critically discuss the main aspects of enzymology, synthesis, and metabolism of ADMA as a prerequisite for understanding the molecular mechanisms through which high concentrations of ADMA could contribute to promoting cardiovascular diseases. ADMA represents a new target for pharmacological modulation of cardiovascular endothelial function and therefore, there is a possibility of using selective pharmacological ADMA lowering drugs in cardiovascular disease with endothelial dysfunction and high plasma ADMA levels.

A multicenter study of asymmetric and symmetric dimethylarginine as predictors of mortality risk in hospitalized COVID-19 patients

Mortality of patients hospitalized with COVID-19 has remained high during the consecutive SARS-CoV-2 pandemic waves. Early discrimination of patients at high mortality risk is crucial for optimal patient care. Symmetric (SDMA) and asymmetric dimethylarginine (ADMA) have been proposed as possible biomarkers to improve risk prediction of COVID-19 patients. We measured SDMA, ADMA, and other L-arginine-related metabolites in 180 patients admitted with COVID-19 in four German university hospitals as compared to 127 healthy controls. Patients were treated according to accepted clinical guidelines and followed-up until death or hospital discharge. Classical inflammatory markers (leukocytes, CRP, PCT), renal function (eGFR), and clinical scores (SOFA) were taken from hospital records. In a small subgroup of 23 COVID-19 patients, sequential blood samples were available and analyzed for biomarker trends over time until 14 days after admission. Patients had significantly elevated SDMA, ADMA, and L-ornithine and lower L-citrulline concentrations than controls. Within COVID-19 patients, SDMA and ADMA were significantly higher in non-survivors (n = 41, 22.8%) than in survivors. In ROC analysis, the optimal cut-off to discriminate non-survivors from survivors was 0.579 µmol/L for SDMA and 0.599 µmol/L for ADMA (both p < 0.001). High SDMA and ADMA were associated with odds ratios for death of 11.45 (3.37–38.87) and 5.95 (2.63–13.45), respectively. Analysis of SDMA and ADMA allowed discrimination of a high-risk (mortality, 43.7%), medium-risk (15.1%), and low-risk group (3.6%); risk prediction was significantly improved over classical laboratory markers. We conclude that analysis of ADMA and SDMA after hospital admission significantly improves risk prediction in COVID-19.

Evaluation of endothelial glycocalyx injury biomarkers in feline hemotropic mycoplasmosis

The present study aimed to investigate endothelial glycocalyx (eGCx) damage in cats with feline hemotropic mycoplasmosis caused by Mycoplasma haemofelis using selected biomarkers and to determine the diagnostic and prognostic significance of these biomarkers. The study included 25 cats with feline hemotropic mycoplasmosis and 10 healthy cats. Clinical examination, blood gas analysis, complete blood count, and biochemical analysis were performed. Hemotropic mycoplasmosis diagnosed by microscopic examination and molecularly confirmed by PCR targeting the Mycoplasma haemofelis 16s rRNA gene. To evaluate endothelial glycocalyx damage, syndecan-1, endothelin-1 (ET-1), asymmetric dimethylarginine (ADMA), and vascular endothelial growth factor-A (VEGF-A) concentrations were measured using cat-specific commercial ELISA kits. Of the cats with feline hemotropic mycoplasmosis, 14 (56%) survived and 11 (44%) died. While syndecan-1 and ET-1 concentrations were significantly higher in cats with hemotropic mycoplasmosis compared to the control group (p < 0.001), no statistically significant difference was found for ADMA and VEGF-A concentrations (p > 0.05). Endothelial glycocalyx biomarkers showed significant correlations with each other and with hematological parameters (p < 0.01). The results of the ROC analysis showed that ET-1 with area under the curve (AUC) of 0.821 (p < 0.01) and VEGF-A with AUC of 0.805 (p < 0.010) were found to be significant prognostic indicators. In conclusion, this study demonstrated that serum syndecan-1 and ET-1 can be used as diagnostic and serum ET-1 and VEGF-A as prognostic biomarkers in cats with hemotropic mycoplasmosis. Our results indicate the development of eGCx damage in feline hemotropic mycoplasmosis and suggest that glycocalyx disruption may contribute to the pathogenesis of the disease.

PROLONGED ENDOTHELIAL DYSFUNCTION IN POST-COVID-19 HYPERTENSIVE PATIENTS

Objective: to investigate the endothelial function in hypertensive patients after 1.5 ± 0.4 years after COVID-19 recovery. Design and method: We studied 64 treated hypertensive patients divided into 2 groups: 39 patients recovered from mild to moderate COVID-19 in 2020-2022 years (1st group) and 25 patients were not ill with COVID-19 (2nd group). All patients were vaccinated against COVID-19. The clinical characteristics and laboratory finding measurements were evaluated. Results: There were no significant differences in sex, duration of hypertension, frequency of family history of premature CVD, smoking, alcohol consumption, BMI, and presence of concomitant DM, CAD, stroke/TIA, atrial fibrillation, heart failure, office BP between the 2 groups. The patients in 1st group were younger and had higher GFR than patients in 2nd group (respectively, 57.9 ± 1.0 vs 61.1 ± 1.5 years, P = 0.03 and 83.2 ± 3.4 vs 71.9 ± 3.7 ml/ min/1.73m2, P = 0.03). The levels of anti-spike IgG antibodies by 21.3% were higher in vaccinated patients with prior COVID-19 than in patients without prior COVID-19. Serum IL-10 and TNF- α concentrations did not differ between groups. However, serum levels of asymmetric dimethylarginine (ADMA) (0.64 ± 0.02 vs 0.53 ± 0.02 μmol/l, P = 0.047), CRP (8.6 ± 2.5 vs 4.3 ± 0.6 mg/l, P = 0.049), 24-h albuminuria (28.1 ± 3.8 vs 14.1 ± 2.3 mg/day, P = 0.048) were higher in post-COVID-19 patients than in patients of 2nd group. Conclusions: After 1.5 ± 0.4 years of recovery from COVID-19, the hypertensive patients who received the vaccine were found to have greater activation of systemic inflammation, higher levels of albuminuria, and higher blood ADMA concentrations compared to vaccinated individuals who did not have COVID-19. This fact may indicate a long-lasting dysfunction of the endothelium after suffering from COVID-19 and the absence of such an effect after vaccination without a history of COVID-19.

Arginine-NO metabolites are associated with morbidity in single ventricle infants undergoing stage 2 palliation.

Infants with single ventricle heart disease (SVHD) suffer morbidity from insufficient pulmonary blood flow, which may be related to impaired arginine metabolism. No prior study has reported quantitative mapping of arginine metabolites to evaluate the relationship between circulating metabolite levels and outcomes. Prospective cohort study of 75 SVHD cases peri-Stage 2 and 50 healthy controls. We targeted pre- and post-op absolute serum quantification of 9 key members of the arginine metabolism pathway by tandem mass spectrometry. Primary outcomes were length of stay (LOS) and post-Stage 2 hypoxemia. Pre-op cases showed alteration in 6 metabolites including decreased arginine and increased asymmetric dimethyl arginine (ADMA) levels compared to controls. Post-op cases demonstrated decreased arginine and citrulline levels persisting through 48 h. Adjusting for clinical variables, lower pre-op and 2 h post-op concentrations of multiple metabolites, including arginine and citrulline, were associated with longer post-op LOS (p < 0.01). Increased ADMA at 24 h was associated with greater post-op hypoxemia burden (p < 0.05). Arginine metabolism is impaired in interstage SVHD infants and is further deranged following Stage 2 palliation. Patients with greater metabolite alterations experience greater post-op morbidity. Decreased arginine metabolism may be an important driver of pathology in SVHD. Interstage infants with SVHD have significantly altered arginine-nitric oxide metabolism compared to healthy children with deficiency of multiple pathway intermediates persisting through 48 h post-Stage 2 palliation. After controlling for clinical covariates and classic catheterization-derived predictors of Stage 2 readiness, both lower pre-operation and lower post-operation circulating metabolite levels were associated with longer post-Stage 2 LOS while increased post-Stage 2 ADMA concentration was associated with greater post-op hypoxemia. Arginine metabolism mapping offers potential for development using personalized medicine strategies as a biomarker of Stage 2 readiness and therapeutic target to improve pulmonary vascular health in infants with SVHD.

Potential Mechanisms for Organoprotective Effects of Exogenous Nitric Oxide in an Experimental Study.

Performing cardiac surgery under cardiopulmonary bypass (CPB) and circulatory arrest (CA) provokes the development of complications caused by tissue metabolism, microcirculatory disorders, and endogenous nitric oxide (NO) deficiency. This study aimed to investigate the potential mechanisms for systemic organoprotective effects of exogenous NO during CPB and CA based on the assessment of dynamic changes in glycocalyx degradation markers, deformation properties of erythrocytes, and tissue metabolism in the experiment. A single-center prospective randomized controlled study was conducted on sheep, n = 24, comprising four groups of six in each. In two groups, NO was delivered at a dose of 80 ppm during CPB ("CPB + NO" group) or CPB and CA ("CPB + CA + NO"). In the "CPB" and "CPB + CA" groups, NO supply was not carried out. NO therapy prevented the deterioration of erythrocyte deformability. It was associated with improved tissue metabolism, lower lactate levels, and higher ATP levels in myocardial and lung tissues. The degree of glycocalyx degradation and endothelial dysfunction, assessed by the concentration of heparan sulfate proteoglycan and asymmetric dimethylarginine, did not change when exogenous NO was supplied. Intraoperative delivery of NO provides systemic organoprotection, which results in reducing the damaging effects of CPB on erythrocyte deformability and maintaining normal functioning of tissue metabolism.

Arginine metabolomics in mood disorders

Alterations of nitric oxide (NO) homeostasis have been described in mood disorders. However, the analytical challenges associated with the direct measurement of NO have prompted the search for alternative biomarkers of NO synthesis. We investigated the published evidence of the association between these alternative biomarkers and mood disorders (depressive disorder or bipolar disorder). Electronic databases were searched from inception to the June 30, 2023. In 20 studies, there was a trend towards significantly higher asymmetric dimethylarginine (ADMA) in mood disorders vs. controls (p = 0.072), and non-significant differences in arginine (p = 0.29), citrulline (p = 0.35), symmetric dimethylarginine (SDMA; p = 0.23), and ornithine (p = 0.42). In subgroup analyses, the SMD for ADMA was significant in bipolar disorder (p < 0.001) and European studies (p = 0.02), the SMDs for SDMA (p = 0.001) and citrulline (p = 0.038) in European studies, and the SMD for ornithine in bipolar disorder (p = 0.007), Asian (p = 0.001) and American studies (p = 0.005), and patients treated with antidepressants (p = 0.029). The abnormal concentrations of ADMA, SDMA, citrulline, and ornithine in subgroups of mood disorders, particularly bipolar disorder, warrant further research to unravel their pathophysiological role and identify novel treatments in this group (The protocol was registered in PROSPERO: CRD42023445962)

Associations between Aging and Vitamin D Status with Whole-Body Nitric Oxide Production and Markers of Endothelial Function

BackgroundAging and vitamin D deficiency have been associated with reduced nitric oxide (NO) synthesis and impaired endothelial function (EF) but the evidence in humans remains weak. ObjectivesTwo independent cross-sectional studies were designed to evaluate the association between age, sex, and plasma vitamin D concentrations with physiological and biochemical biomarkers of NO synthesis and EF in young and older healthy participants (Study 1) and in overweight and obese postmenopausal females (Study 2). MethodsIn Study 1, 40 young (20–49 y) and older (50–75 y) males and females (10 participants per age and sex group) were included. Resting blood pressure and ear-to-finger peripheral pulse wave velocity (PWV) were measured. A stable-isotopic method was used to determine whole-body NO production. Plasma 25-hydroxyvitamin D (25(OH)D), nitrate, nitrite, and asymmetric dimethylarginine (ADMA) concentrations were determined. In Study 2, 80 older overweight and obese females (age 61.2 ± 6.2 y, body mass index 29.5 ± 4.4 kg/m2) were recruited. Postocclusion reactive hyperemia (PORH) and peripheral PWV were measured. Plasma concentrations of 25(OH)D, nitrate, cyclic guanosine monophosphate, 3-nitrotyrosine (3-NT), endothelin-1, vascular endothelial growth factor, and ADMA were determined. ResultsIn Study 1, whole-body NO production was significantly greater in young compared with older participants (0.61 ± 0.30 μmol·h−1·kg−1 compared with 0.39 ± 0.10 μmol·h−1·kg−1, P = 0.01) but there was no evidence of a sex difference (P = 0.81). Plasma 25(OH)D concentration was not associated with PWV (r = 0.18, P = 0.28) or whole-body NO production (r = −0.20, P = 0.22). Plasma ADMA concentration was associated positively with age (r = 0.35, P = 0.03) and negatively with whole-body NO production (r = −0.33, P = 0.04). In Study 2, age was associated with lower PORH (r = −0.28, P = 0.02) and greater ADMA concentrations (r = 0.22, P = 0.04). Plasma 25(OH)D concentration was inversely associated with 3-NT concentrations (r = −0.31, P = 0.004). ConclusionsOlder age was associated with lower whole-body NO production. Plasma vitamin D concentrations were not associated with NO production or markers of EF but showed a weak, significant correlation with oxidative stress in postmenopausal overweight females.

Asymmetric and symmetric dimethylarginine in high altitude pulmonary hypertension (HAPH) and high altitude pulmonary edema (HAPE)

Introduction: High altitude exposure may lead to high altitude pulmonary hypertension (HAPH) and high altitude pulmonary edema (HAPE). The pathophysiologic processes of both entities have been linked to decreased nitric oxide (NO) availability.Methods: We studied the effect of acute high altitude exposure on the plasma concentrations of asymmetric (ADMA) and symmetric dimethylarginine (SDMA), L-arginine, L-ornithine, and L-citrulline in two independent studies. We further investigated whether these biomarkers involved in NO metabolism were related to HAPH and HAPE, respectively. Fifty (study A) and thirteen (study B) non-acclimatized lowlanders were exposed to 4,559 m for 44 and 67 h, respectively. In contrast to study A, the participants in study B were characterized by a history of at least one episode of HAPE. Arterial blood gases and biomarker concentrations in venous plasma were assessed at low altitude (baseline) and repeatedly at high altitude. HAPE was diagnosed by chest radiography, and HAPH by measuring right ventricular to atrial pressure gradient (RVPG) with transthoracic echocardiography. AMS was evaluated with the Lake Louise Score (LLS) and the AMS-C score.Results: In both studies SDMA concentration significantly increased at high altitude. ADMA baseline concentrations were higher in individuals with HAPE susceptibility (study B) compared to those without (study A). However, upon high altitude exposure ADMA only increased in individuals without HAPE susceptibility, while there was no further increase in those with HAPE susceptibility. We observed an acute and transient decrease of L-ornithine and a more delayed but prolonged reduction of L-citrulline during high altitude exposure. In both studies SDMA positively correlated and L-ornithine negatively correlated with RVPG. ADMA was significantly associated with the occurrence of HAPE (study B). ADMA and SDMA were inversely correlated with alveolar PO2, while L-ornithine was inversely correlated with blood oxygenation and haemoglobin levels, respectively.Discussion: In non-acclimatized individuals ADMA and SDMA, two biomarkers decreasing endothelial NO production, increased after acute exposure to 4,559 m. The observed biomarker changes suggest that both NO synthesis and arginase pathways are involved in the pathophysiology of HAPH and HAPE.

The relationship of asymmetric dimethylarginine levels with uncontrolled arterial hypertension and hypertension disease stage

Background: Patients with treatment-resistant hypertension have a worse cardiovascular prognosis compared to those who achieve their target levels of blood pressure (BP). One of biochemical and clinical markers of a decreased response to antihypertensive therapy can be asymmetric dimethylarginine (ADMA), a molecule that reduces formation of nitric oxide and promotes endothelial dysfunction and vasoconstriction.&#x0D; Aim: To assess the status of the nitrogen oxide synthesis system and clinical and laboratory profile in patients, depending on the hypertensive disease stage, who achieved or not achieved their target BP levels during hospitalization.&#x0D; Materials and methods: We performed аn observational retrospective uncontrolled study in a consecutive sample of 192 patients aged 45–65 years who were admitted to the City Clinical Hospital No. 25 (city of Novosibirsk) with a diagnosis of uncomplicated hypertensive crisis. On the day of discharge, the patients were retrospectively divided into 2 groups. Group 1 included patients who achieved their target BP during hospitalization (target BP group, n = 116). Group 2 included patients with uncontrolled hypertension, in whom the administration of three antihypertensive drugs including a diuretic in optimal or maximal tolerated doses did not result in the achievement of the target BP below 140 and/or 90 mm Hg during hospitalization (non-target BP group, n = 76).&#x0D; The following parameters were measured: ADMA, symmetrical dimethylarginine (SDMA), N-monomethyl-L-arginine (NMMA), and total nitric oxide.&#x0D; Results: Serum ADMA concentrations (Me [Q25%; Q75%] were increasing with the stage of hypertension: stage I, 0.75 µmol/L [0.66; 0.78], stage II, 1.14 µmol/L [0.87; 1.39], stage III, 1.38 µmol/L [1.22; 1.49] (p 0.0001, Kruskal-Wallis test). In the pairwise comparison, the difference between all these subgroups was significant at p 0.01. In the patients with uncontrolled arterial hypertension ADMA levels were increased compared to those in the target BP group: 1.2 µmol/L [0.99; 1.47] vs 1.07 [0.79; 1.34] µmol/L (p = 0.002). The proportion of patients with type 2 diabetes mellitus among those with uncontrolled arterial hypertension was 31.2% (24/76), while in the target BP group there were only 3.5% of such patients (4/116) (odds ratio 12.57, 95% confidence interval 4.15–38.05; p = 0.00001).&#x0D; Conclusion: ADMA measurement may help identify patients with a potential poor response to antihypertensive therapy. This should be taken into account when choosing a treatment regimen and BP monitoring. In addition, ADMA seems to be a promising target for the development of new drug classes.

Plasma concentrations of asymmetric dimethylarginine in Endothelial injury in HIV associated preeclampsia.

Plasma concentrations of asymmetric dimethylarginine in Endothelial injury in HIV associated preeclampsia.

Renal hemodynamics in patients with resistant hypertension and type 2 diabetes mellitus.

Aim To study renal hemodynamics in patients with resistant arterial hypertension (RAH) in combination with type 2 diabetes mellitus (DM2) and to identify factors involved in the increase in intrarenal vascular resistance.Material and methods This study included 59 patients (25 men) with RAH in combination with DM2. Mean age of patients was 60.3±7.9 years; 24-h blood pressure (24-BP) (systolic, diastolic, SBP/DBP) was 158.0±16.3 / 82.5±12.7 mm Hg during the treatment with 4.3 [4.0;5.0] antihypertensive drugs; glycated hemoglobin (HbA1c) was 7.5±1.5 %; estimated glomerular filtration rate (eGFR) was 73.1±21.8 ml/min / 1.73 m2 (CKD-EPI equation). Measurement of office BP, 24-h BP monitoring, renal artery (RA) Doppler, routine lab tests including determination of GFR (CKD-EPI), 24-h urine albumin excretion, and ELISA measurement of blood lipocalin-2, cystatin C, high-sensitive C-reactive protein (hsCRP), and asymmetric dimethylarginine (ADMA) were performed for all patients.Results Incidence of increased RA resistive index (RI) was 39% despite the high rate of vasodilator treatment (93% for renin-angiotensin-aldosterone system inhibitors, 78% for calcium antagonists). According to a correlation and regression analysis, RA RI values were correlated with the kidney function (r=-0.46, p&lt;0.001 for eGFR, r=0.56; p=0.006 for lipocalin-2), age (r=0.54, p&lt;0.001), increases in concentrations of hsCRP (r=0.35, p&lt;0.001) and ADMA (r=0.39, p=0.028), the increase in vascular stiffness (r=0.59, p&lt;0.001 for pulse BP (PBP) as well as DM2 duration, and HbA1c (r=0.33, p&lt;0.001 for both). The independent association of RA RI with the age, PBP, and duration of DM2 was confirmed by the results of multivariate regression analysis. According to the ROC analysis, the threshold level of RA RI corresponding to a decrease in GFR &lt;60 ml / min / 1.73 m2 was ≥0.693 conv. units.Conclusion In more than one third of patients with RAH in combination with DM2, increased renal vascular resistance was documented, which was closely associated with impaired kidney function, age, DM2 duration and severity, and markers of low-grade inflammation, endothelial dysfunction, and vascular stiffness. The value of RA RI ≥0.693 conv. units was a threshold for the development of chronic kidney disease (CKD).

Validation of Serum ADMA Levels as a Biomarker for Assessing Cardiovascular Risk in Patients with Coronary Heart Disease: A Study from a Tertiary Care Hospital in Pakistan

Objectives: The diagnostic potential of serum asymmetric dimethylarginine (ADMA) levels as a biomarker for cardiovascular risk has been investigated in various populations, but no such study has been reported in Pakistan. This study aimed to assess the diagnostic efficiency of serum ADMA levels in detecting cardiovascular risk in patients with coronary heart disease (CHD). Methodology: A cross-sectional study was conducted at the Chaudhry Pervaiz Elahi Institute of Cardiology (CPEIC), Wazirabad, Pakistan, using a consecutive sampling technique to ensure randomization. One hundred individuals were divided into two groups (CHD patients and healthy controls), and blood samples were collected between January 2022 and November 2022. Serum ADMA levels were measured using an enzyme-linked immunosorbent assay (ELISA), and statistical analysis was performed to determine the area under the receiver operating characteristic (ROC) curve (AUC). Results: The mean age of CHD patients' serum samples was 58.6 ± 7.39 years (p&lt;0.001) compared to 42.26 ± 14.4 years (p&lt;0.001) in healthy controls. The mean ADMA concentration in the serum of CHD patients was determined as 1.37 ± 0.26 µmol/L (p&lt;0.001) compared to 0.812 ± 0.207 µmol/L (p&lt;0.001) in healthy controls. The AUC on the ROC curve was determined as 0.95, indicating high diagnostic accuracy. ADMA's sensitivity, specificity, and overall accuracy were determined as 82%, 88%, and 85%, respectively. Conclusion: In conclusion, serum ADMA levels demonstrate a promising potential as a biomarker for assessing cardiovascular risk. The findings of this study suggest that ADMA measurements could be utilized as a diagnostic tool in CHD patients, aiding in the identification and management of cardiovascular risk in the Pakistani population. Further research is warranted to validate these findings and explore the utility of ADMA in more extensive and diverse cohorts.

The role of asymmetric dimethylarginine (ADMA) in COVID-19: association with respiratory failure and predictive role for outcome

We aimed to assess the potential role of Asymmetric dimethylarginine (ADMA) in conditioning respiratory function and pulmonary vasoregulation during Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV2) infection. Within 72 h from admission, samples from 90 COVID-19 patients were assessed for ADMA, SDMA, L-arginine concentrations. In addition to classical statistics, patients were also clustered by a machine learning approach according to similar features. Multivariable analysis showed that C-reactive protein (OR 1.012), serum ADMA (OR 4.652), white blood cells (OR = 1.118) and SOFA (OR = 1.495) were significantly associated with negative outcomes. Machine learning-based clustering showed three distinct clusters: (1) patients with low severity not requiring invasive mechanical ventilation (IMV), (2) patients with moderate severity and respiratory failure whilst not requiring IMV, and (3) patients with highest severity requiring IMV. Serum ADMA concentration was significantly associated with disease severity and need for IMV although less pulmonary vasodilation was observed by CT scan. High serum levels of ADMA are indicative of high disease severity and requirement of mechanical ventilation. Serum ADMA at the time of hospital admission may therefore help to identify COVID-19 patients at high risk of deterioration and negative outcome.

Association of urine and plasma ADMA with atherosclerotic risk in DKD cardiovascular disease risk in diabetic kidney disease: findings from the Chronic Renal Insufficiency Cohort (CRIC) study.

Chronic kidney disease (CKD) is associated with atherosclerotic cardiovascular disease (ASCVD) risk, especially among those with diabetes. Altered metabolism of solutes that accumulate in CKD [asymmetric dimethylarginine (ADMA), symmetric dimethylarginine (SDMA) and trimethylamine N-oxide (TMAO)] may reflect pathways linking CKD with ASCVD. This case-cohort study included Chronic Renal Insufficiency Cohort participants with baseline diabetes, estimated glomerular filtration rate <60mL/min/1.73 m2, and without prior history for each outcome. The primary outcome was incident ASCVD (time to first myocardial infarction, stroke or peripheral artery disease event) and secondary outcome was incident heart failure. The subcohort comprised randomly selected participants meeting entry criteria. Plasma and urine ADMA, SDMA and TMAO concentrations were determined by liquid chromatography-tandem mass spectrometry. Associations of uremic solute plasma concentrations and urinary fractional excretions with outcomes were evaluated by weighted multivariable Cox regression models, adjusted for confounding covariables. Higher plasma ADMA concentrations (per standard deviation) were associated with ASCVD risk [hazard ratio (HR) 1.30, 95% confidence interval (CI) 1.01-1.68]. Lower fractional excretion of ADMA (per standard deviation) was associated with ASCVD risk (HR 1.42, 95% CI 1.07-1.89). The lowest quartile of ADMA fractional excretion was associated with greater ASCVD risk (HR 2.25, 95% CI 1.08-4.69) compared with the highest quartile. Plasma SDMA and TMAO concentration and fractional excretion were not associated with ASCVD. Neither plasma nor fractional excretion of ADMA, SDMA and TMAO were associated with incident heart failure. These data suggest that decreased kidney excretion of ADMA leads to increased plasma concentrations and ASCVD risk.