dimethylarginine and Renal-Insufficiency--Chronic

Symmetric dimethylarginine (SDMA) is a valuable surrogate marker for decreased glomerular filtration rate (GFR) and is incorporated into the International Renal Interest Society (IRIS) guidelines for diagnosing, staging, and treating chronic kidney disease (CKD). SDMA increases above the reference interval with smaller reductions in GFR rate than does creatinine and persistent mild increases in SDMA can be used to diagnose early-stage CKD. Evaluation of both SDMA and creatinine is recommended for diagnosis and monitoring of animals with CKD.

Topics: Animals; Arginine; Biomarkers; Cat Diseases; Cats; Creatinine; Dog Diseases; Dogs; Female; Kidney; Male; Renal Insufficiency, Chronic

The Cardiorenal Syndrome type 4 (CRS-4) defines a pathological condition in which a primary chronic kidney disease (CKD) leads to a chronic impairment of cardiac function. The pathophysiology of CRS-4 and the role of arterial stiffness remain only in part understood. Several uremic toxins, such as uric acid, phosphates, advanced glycation end-products, asymmetric dimethylarginine, and endothelin-1, are also vascular toxins. Their effect on the arterial wall may be direct or mediated by chronic inflammation and oxidative stress. Uremic toxins lead to endothelial dysfunction, intima-media thickening and arterial stiffening. In patients with CRS-4, the increased aortic stiffness results in an increase of cardiac workload and left ventricular hypertrophy whereas the loss of elasticity results in decreased coronary artery perfusion pressure during diastole and increased risk of myocardial infarction. Since the reduction of arterial stiffness is associated with an increased survival in patients with CKD, the understanding of the mechanisms that lead to arterial stiffening in patients with CRS4 may be useful to select potential approaches to improve their outcome. In this review we aim at discussing current understanding of the pathways that link uremic toxins, arterial stiffening and impaired cardiac function in patients with CRS-4.

Topics: Aorta; Arginine; Autonomic Nervous System Diseases; Bone Diseases, Metabolic; Cardio-Renal Syndrome; Cardiovascular Diseases; Chronic Disease; Endothelium, Vascular; Glycation End Products, Advanced; Humans; Inflammation; Myocardial Infarction; Oxidative Stress; Phosphorus; Renal Insufficiency, Chronic; Toxins, Biological; Tunica Intima; Uric Acid; Vascular Stiffness; Vasculitis

The picture of HDL cholesterol (HDL-C) as the "good" cholesterol has eroded. This is even more surprising because there exists strong evidence that HDL-C is associated with cardiovascular disease (CVD) in the general population as well as in patients with impairment of kidney function and/or progression of CKD. However, drugs that dramatically increase HDL-C have mostly failed to decrease CVD events. Furthermore, genetic studies took the same line, as genetic variants that have a pronounced influence on HDL-C concentrations did not show an association with cardiovascular risk. For many, this was not surprising, given that an HDL particle is highly complex and carries >80 proteins and several hundred lipid species. Simply measuring cholesterol might not reflect the variety of biologic effects of heterogeneous HDL particles. Therefore, functional studies and the involvement of HDL components in the reverse cholesterol transport, including the cholesterol efflux capacity, have become a further focus of study during recent years. As also observed for other aspects, CKD populations behave differently compared with non-CKD populations. Although clear disturbances have been observed for the "functionality" of HDL particles in patients with CKD, this did not necessarily translate into clear-cut associations with outcomes.

Topics: Advanced Oxidation Protein Products; Apolipoprotein A-V; Apolipoprotein L1; Arginine; Cardiovascular Diseases; Cholesterol; Cholesterol, HDL; Glomerular Filtration Rate; Humans; Lipid Metabolism; MicroRNAs; Renal Insufficiency, Chronic; Serum Amyloid A Protein

Endothelial dysfunction occurs in chronic kidney disease (CKD) and increases the risk for cardiovascular disease. The mechanisms of endothelial dysfunction seem to evolve throughout kidney disease progression, culminating in reduced L-arginine transport and impaired nitric oxide bioavailability in advanced disease. This review examines the hypothesis that aerobic exercise may reverse endothelial dysfunction by improving endothelial cell L-arginine uptake in CKD.

Topics: Arginine; Biological Availability; Biological Transport; Cardiovascular Diseases; Disease Progression; Endothelium, Vascular; Exercise; Humans; Nitric Oxide; Oxidative Stress; Renal Insufficiency, Chronic; Risk Factors

Dosing of most drugs must be adapted in renal insufficiency, making accurate assessment of renal function essential in clinical medicine. Furthermore, even modest impairment of renal function has been recognized as a cardiovascular risk factor. The purpose of this analysis was to identify the role of symmetric dimethylarginine (SDMA), the structural isomer of the cardiovascular risk marker asymmetric dimethylarginine, as an endogenous marker of renal function.. Comprehensive searches of Medline and the Cochrane Library from 1970 to February 2006 were performed to identify studies that evaluated the correlation between SDMA and renal function. The search was augmented by scanning references of identified articles and reviews. The correlation coefficients (R) were recorded from each study for the values of 1/SDMA and clearance estimates and for SDMA and creatinine levels. The summary correlation coefficients with 95% confidence intervals (CIs) were pooled using the random-effects method.. In 18 studies involving 2136 patients systemic SDMA concentrations correlated highly with inulin clearance [R = 0.85 (CI 0.76-0.91, P < 0.0001)], as well as with various clearance estimates combined [R = 0.77 (CI 0.65-0.85, P < 0.0001)] and serum creatinine [R = 0.75 (CI 0.46-089, P < 0.0001)].. SDMA exhibits some properties of a reliable marker of renal function. Future studies have to clarify whether SDMA is indeed suited to improve diagnosis and eventually optimize care of patients.

Topics: Arginine; Biomarkers; Cardiovascular Diseases; Creatinine; Female; Humans; Inulin; Male; Prognosis; Renal Insufficiency, Chronic; Retrospective Studies; Risk Factors

In this study, we examined the association between chronic kidney disease (CKD) and insulin resistance. In a patient cohort with nondiabetic stages 2-5 CKD, estimated glomerular filtration rate (eGFR) was negatively correlated and the plasma aldosterone concentration was independently associated with the homeostasis model assessment of insulin resistance. Treatment with the mineralocorticoid receptor blocker spironolactone ameliorated insulin resistance in patients, and impaired glucose tolerance was partially reversed in fifth/sixth nephrectomized rats. In these rats, insulin-induced signal transduction was attenuated, especially in the adipose tissue. In the adipose tissue of nephrectomized rats, nuclear mineralocorticoid receptor expression, expression of the mineralocorticoid receptor target molecule SGK-1, tissue aldosterone content, and expression of the aldosterone-producing enzyme CYP11B2 increased. Mineralocorticoid receptor activation in the adipose tissue was reversed by spironolactone. In the adipose tissue of nephrectomized rats, asymmetric dimethylarginine (ADMA; an uremic substance linking uremia and insulin resistance) increased, the expression of the ADMA-degrading enzymes DDAH1 and DDAH2 decreased, and the oxidative stress increased. All of these changes were reversed by spironolactone. In mature adipocytes, aldosterone downregulated both DDAH1 and DDAH2 expression, and ADMA inhibited the insulin-induced cellular signaling. Thus, activation of mineralocorticoid receptor and resultant ADMA accumulation in adipose tissue has, in part, a relevant role in the development of insulin resistance in CKD.

Topics: Adipose Tissue; Aged; Aldosterone; Amidohydrolases; Animals; Arginine; Cell Nucleus; Cytochrome P-450 CYP11B2; Female; Glomerular Filtration Rate; Glucose Tolerance Test; Homeostasis; Humans; Immediate-Early Proteins; Insulin Resistance; Male; Middle Aged; Mineralocorticoid Receptor Antagonists; Nephrectomy; Oxidative Stress; Protein Serine-Threonine Kinases; Rats; Rats, Sprague-Dawley; Receptors, Mineralocorticoid; Renal Insufficiency, Chronic; Renin; Signal Transduction; Spironolactone

Cardiovascular disease (CVD) and chronic kidney disease (CKD) constitute substantial burdens for public health. The identification and validation of risk markers for CVD and CKD in epidemiological studies requires frequent adaption of existing analytical methods as well as development of new methods. In this study, an analytical procedure to simultaneously quantify ten endogenous biomarkers for CVD and CKD is described. An easy-to-handle sample preparation requiring only 20 µL of human plasma is followed by liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS). The method was successfully validated according to established guidelines meeting required criteria for accuracy, precision, recovery, linearity, selectivity, and limits of quantification. The scalability of the method for application in larger cohorts was assessed using a set of plasma samples from healthy volunteers (n = 391) providing first reference values for the recently established biomarker N

Topics: Adolescent; Adult; Arginine; Biomarkers; Cardiovascular Diseases; Carnitine; Chromatography, Liquid; Citrulline; Creatinine; Female; Homoarginine; Humans; Lysine; Male; Middle Aged; Ornithine; Reference Values; Renal Insufficiency, Chronic; Tandem Mass Spectrometry; Young Adult

Chronic kidney disease (CKD) in childhood is characterised by the accumulation of uraemic toxins resulting in a multisystem disorder that has a negative impact on quality of life. Childhood CKD is predominantly defined by a decrease in glomerular filtration rate, estimated (eGFR) by a single serum measurement of endogenous biomarkers, e.g. creatinine. The objective of this study was to evaluate how accurately eGFR predicts the concentration of uraemic toxins in a paediatric CKD cohort.. In 65 children (10.8 [5.1; 14.7] years) with CKD (eGFR 44 [20; 64] mL/min/1.73 m. Updated Schwartz eGFR was correlated reasonably well with concentrations of creatinine (r = -0.98), urea (r. This study demonstrates that eGFR poorly predicts concentrations of protein-bound uraemic toxins, UA and ADMA in childhood CKD. Therefore, eGFR only partially reflects the complexity of the accumulation pattern of uraemic toxins in childhood CKD.

Topics: Adolescent; Arginine; Biomarkers; Child; Child, Preschool; Female; Glomerular Filtration Rate; Humans; Male; Renal Insufficiency, Chronic; Uremia; Uric Acid

Arginine, asymmetric dimethylarginine (ADMA), symmetric dimethylarginine (SDMA), arginine/ADMA ratio and homoarginine could potentially affect nitric oxide production and have been studied in relation to cardiovascular risk (CVR) in various clinical populations. Prospective studies on the CVR associated with arginine/ADMA ratio and homoarginine in patients with moderate chronic kidney disease (CKD) are still scarce. We have studied how arginine, homoarginine and dimethylated arginine can predict cardiovascular events in such a population.. We measured plasma concentrations of arginine (P-arginine), ADMA (P-ADMA), SDMA (P-SDMA), homoarginine (P-homoarginine) and other covariates in 160 patients with predialytic CKD (mean age 57 years and mean eGFR 43 mL/min/1.73 m(2)) and followed them for 58 months in median. The risks of fatal and non-fatal cardiovascular events associated with the predictors were evaluated with multivariable Cox proportional hazard analysis.. There were 31 cardiovascular events during the observation period. In a multivariable model adjusted for age, sex, previous cardiovascular disease, P-cystatin C and P-homoarginine, the hazard ratio (HR) associated with an increase in arginine/ADMA ratio by 10 was 0.83 (P=0.03). The HR of a 1 μmol/L increase in P-homoarginine in the same model was 1.78 (P=0.01). A statistically significant interaction between P-homoarginine and P-cystatin C was found in an extended multivariable model. P-SDMA was not associated with increased CVR after adjustment for basic covariates.. This study demonstrates a negative association between arginine/ADMA ratio and CVR in CKD patients and a positive association between P-homoarginine and CVR. The latter is in contrast to what has been demonstrated by others.

Topics: Adult; Aged; Arginine; Biomarkers; Cardiovascular Diseases; Female; Follow-Up Studies; Homoarginine; Humans; Male; Middle Aged; Prospective Studies; Renal Insufficiency, Chronic; Risk Factors

To define the clinical significance of asymmetric dimethylarginine (ADMA) and that of methylenetetrahydrofolate reductase (MTHFR) gene polymorphism as factors of endothelial dysfunction (ED) in the development of early kidney injury in obese patients.. The investigation included 86 patients (64 men and 22 women aged 44 +/- 11 years) with abdominal obesity. Along with physical examination, the authors determined albuminuria, calculated glomerular filtration rate (GFR) using the Modification of Diet in Renal Disease (MDRD) formula, estimated insulin resistance markers (fasting plasma insulin and C-peptide concentrations and homeostatic model assessment (HOMA) index), as well as serum ADMA levels by enzyme immunoassay in all the patients. C677T polymorphism in the MTHFR gene was studied by allele-specific polymerase chain reaction and restriction fragment length polymorphism analysis. Kidney injury (chronic kidney disease (CKD)) was diagnosed using the Kidney Disease Outcomes Quality Initiative (KDOQI) criteria. Early vascular remodeling was determined from the increased intima-media thickness (IMT) of the common carotid artery (CCA).. CKD was diagnosed in 27(31%) patients. The latter, unlike the patients with CKD, were observed to have more pronounced obesity (body mass index (BMI) 36.8 +/- 8.0 and 32.0 +/- 4.7 kg/m2, respectively (p < 0.001)), waist circumference (119 +/- 18 and 109 +/- 11 cm (p = 0.002)), higher levels of C-peptide (1348 +/- 363 and 1028 +/- 363 pmol/I; p < 0.001), insulin (16.9 +/- 7.3 and 11.7 +/- 5.5 microU/ ml; p < 0.001), and HOMA index (4.3 +/- 1.7 and 2.9 +/- 1.5; p < 0.001). In the patients with Stage IIIa CKD, ADMA concentrations (0.77 +/- 0.19 micromol/l) was higher than in those with Stages I (0.58 +/- 0.11 micromol/l; p = 0.048) and II (0.61 +/- 0.13 micromol/l; p = 0.071). An association between ADMA concentrations, CCA IMT, and estimated GFR was revealed in the patients with CKD. The predictors of an estimated GFR reduction in obesity were elevated serum concentrations of ADMA, uric acid, insulin, and HOMA index. The combination of obstructive sleep apnea syndrome and metabolic syndrome increased the risk of CKD by 2.1-fold (95% confidence interval, 1.06-3.14). Evaluation of the impact of MTHFR gene polymorphism on kidney injury in obesity disclosed that the patients with homozygous carriage of the abnormal T allele of the MTHFR gene had a higher risk for Stages I-IIIa CKD (2.60 with 95% confidence interval, 1.32-3.88), more marked obesity and hyperinsulinemia, and increased serum ADMA concentrations.. Insulin resistance and ED hold a central position in the pathogenesis of CKD in obese patients. The mechanisms of the atherosclerotic vascular remodeling associated with elevated serum ADMA concentrations are of paramount importance in the progression of early-stage CKD. The homozygous carriage of the abnormal T allele of the MTHFR gene increases the risk of Stages I-IIIa by more than twice.

Topics: Adult; Arginine; Carotid Artery, Common; Data Interpretation, Statistical; Endothelium, Vascular; Female; Glomerular Filtration Rate; Humans; Hypoxia; Insulin Resistance; Male; Methylenetetrahydrofolate Reductase (NADPH2); Middle Aged; Obesity; Polymorphism, Genetic; Renal Insufficiency, Chronic; Risk Factors; Severity of Illness Index; Tunica Media; Ultrasonography

Mechanisms linking chronic kidney disease (CKD) and adverse outcomes in acute coronary syndromes (ACS) are not fully understood. Among potential key players, reduced nitric oxide (NO) synthesis due to its endogenous inhibitors, asymmetric (ADMA) and symmetric (SDMA) dimethylarginine could be involved. We measured plasma concentration of arginine, ADMA and SDMA and investigated their relationship with CKD and long-term outcome in non-ST-elevation myocardial infarction (NSTEMI).. We prospectively measured arginine, ADMA, and SDMA at hospital admission in 104 NSTEMI patients. CKD was defined as an estimated glomerular filtration rate (eGFR) <60 ml/min/1.73 m(2). We considered a primary end point of combined cardiac death and re-infarction at a median follow-up of 21 months. In CKD (n = 33) and no-CKD (n = 71) patients, arginine and ADMA were similar, whereas SDMA was significantly higher in CKD patients (0.65±0.23 vs. 0.42±0.12 µmol/L; P<0.0001). Twenty-four (23%) patients had an adverse cardiac event during follow-up: 12 (36%) were CKD and 12 (17%) no-CKD patients (P = 0.02). When study population was stratified according to arginine, ADMA and SDMA median values, only SDMA (median 0.46 µmol/L) was associated with the primary end-point (P = 0.0016). In models adjusted for age, hemoglobin and left ventricular ejection fraction, the hazard ratio (HR) for CKD and SDMA were high (HR 2.93, interquartile range [IQR] 1.15-7.53; P = 0.02 and HR 6.80, IQR 2.09-22.2; P = 0.001, respectively) but, after mutual adjustment, only SDMA remained significantly associated with the primary end point (HR 5.73, IQR 1.55-21.2; P = 0.009).. In NSTEMI patients, elevated SDMA plasma levels are associated with CKD and worse long-term prognosis.

Topics: Aged; Arginine; Endpoint Determination; Female; Follow-Up Studies; Humans; Kaplan-Meier Estimate; Kidney Function Tests; Male; Middle Aged; Myocardial Infarction; Nitric Oxide; Proportional Hazards Models; Renal Insufficiency, Chronic; Treatment Outcome; Ultrasonography

Asymmetric dimethylarginine (ADMA) has been suggested as a possible marker of endothelial dysfunction, and interest in its use in clinical practice is increasing. However, the potential role of symmetric dimethylarginine (SDMA) as an endogenous marker of renal function, has been less widely investigated. The aims of the present study were therefore to determine reference values for dimethylarginines in plasma after method validation, and to ascertain ADMA plasma concentrations in patients with disorders characterized by endothelial dysfunction; a further end-point was to investigate the relationship between SDMA plasma concentrations and estimated GFR (eGFR) as well as plasmatic creatinine in patients with chronic kidney disease (CKD).. HPLC with fluorescence detection was used for the determination of plasma dimethylarginines. To verify the clinical usefulness of ADMA and SDMA, values from 4 groups of patients at a high risk of cardiovascular complications as well renal dysfunction (chronic heart failure n=126; type II diabetes n=43; pulmonary arterial hypertension n=17; chronic kidney disease n=42) were evaluated, and compared with the reference values, obtained from 225 blood donors.. The intra- and inter-assay CVs (<5.2%), the absolute and relative recoveries (96-106%) were highly satisfactory. ADMA levels were significantly elevated in all groups of patients compared with controls (p<0.001) with the exception of samples from patients with type II diabetes. SDMA levels were significantly elevated both in the patients with chronic kidney disease and in the patients with type II diabetes complicated by renal insufficiency, the values being closely correlated with both eGFR (R=0.740) and plasmatic creatinine (R=0.700).. The findings made in the present study shows that ADMA levels are significantly increased in patients with diseases associated with endothelial dysfunction This molecule might, therefore, be used as a biochemical marker for the evaluation of endothelial function. Furthermore, the preliminary results reported suggest that SDMA might be a reliable marker of renal function, especially in peadiatric populations, for which the use of eGFR is not recommended.

Topics: Adolescent; Adult; Aged; Arginine; Cardiovascular Diseases; Chromatography, High Pressure Liquid; Creatine; Endothelium, Vascular; Female; Glomerular Filtration Rate; Humans; Kidney Function Tests; Male; Middle Aged; Renal Insufficiency, Chronic; Young Adult

Asymmetric dimethylarginine (ADMA), a methylated L: -arginine (Arg) derivative is associated with endothelial dysfunction, vasoconstriction, and hypertension in animals and humans. We examined the relationship between these derivatives, estimated glomerular filtration rate (eGFR), and awake (AW) and asleep (AS) blood pressure (BP) load in children and adolescents (n = 28) with stage 2-3 chronic kidney disease (CKD) and in matched intra-familial controls (n = 10). Plasma L: -Arg, ADMA, and symmetric dimethylarginine (SDMA) levels were measured by high-performance liquid chromatography-tandem mass spectrometry. Subjects wore a 24-hr ambulatory BP monitor with BP load >95th percentile. ADMA, SDMA/ADMA ratio and SDMA were 38-200% higher in CKD patients while L: -Arg/ADMA and L: -Arg/SDMA ratios and the L: -Arg level were 11-64% lower. The eGFR explained 42-60% of L: -Arg/SDMA, SDMA/ADMA, and SDMA variability (n = 38). Using linear regression, SDMA and SDMA/ADMA separately explained 15-38% of AW and AS systolic (S) BP and diastolic (D) BP load variability (p < 0.001-0.022). Using multivariate stepwise regression with eGFR held constant, SDMA/ADMA was a significant independent variable for AW DBP load (p = 0.03). In conclusion, BP load and a disproportionate elevation of SDMA are seen in children and adolescents with stage 2-3 (mild-moderate) CKD. SDMA is a strong marker for reduced eGFR and serves as a moderate but significant indicator of 24-hr BP load variability.

Topics: Adolescent; Arginine; Blood Pressure; Blood Pressure Monitoring, Ambulatory; Child; Chromatography, High Pressure Liquid; Cross-Sectional Studies; Female; Food Deprivation; Glomerular Filtration Rate; Humans; Hypertension; Male; Renal Insufficiency, Chronic; Tandem Mass Spectrometry