ADMA, C-reactive protein, and albuminuria in untreated essential hypertension: a cross-sectional study

The role of oxidative stress markers in Indonesian chronic kidney disease patients: a cross sectional study

Background: Several aspects of chronic kidney disease (CKD) such as the incidence rate and mortality rate are concerning. Oxidative stress contributes to progression and mortality in patients with CKD; however, a specific correlation between several markers of oxidative stress and the estimated glomerular filtration rate (eGFR) and albumin-creatinine ratio (ACR) in the Indonesian population has not been sufficiently described yet. Methods: This study was an analytic observational study with a sample of 56 patients with CKD in Universitas Airlangga Hospital, Surabaya, Indonesia, from December 2019 – March 2020. The markers for oxidative stress investigated were urinary 8-hydroxy-2 deoxyguanosine (8-OHdG), serum symmetric dimethylarginine (SDMA) and asymmetric dimethylarginine (ADMA). The correlations between each variable of oxidative stress and CKD were analyzed using Pearson analysis. Results: There was a positive correlation between 8-OHdG and eGFR (p=0.00, r=0.51); however, there was a negative correlation between 8-OHdG and ACR (p=0.025, r=-0.30). SDMA and eGFR showed a negative correlation (p=0.00, r=-0.648), while SDMA and ACR showed a positive correlation (p=0.03, r=0.349). ADMA showed a negative correlation with eGFR (p=0.00, r=-0.476). There were significantly decreased 8-OHdG but increased ADMA and SDMA as the CKD stage progressed (p=0.001, p=0.00, and p = 0.00, respectively). Higher urine 8-OHdG was detected in patients without history of hemodialysis, whereas ADMA and SDMA showed higher value in patients with hemodialysis (p=0.00, p=0.00, and p=0.004, respectively), patients with history of diabetes mellitus (DM) had higher mean 8-OHdG (p 0.000) yet lower serum ADMA and SDMA (p=0.004 and p=0.003, respectively). Conclusions: In patients with CKD in Indonesia, the markers for oxidative stress 8-OHdG, SDMA, and ADMA are correlated with eGFR and ACR levels. There were also significant difference in 8-OHdG, SDMA, and ADMA levels among CKD stages, between dialysis vs non dialysis, and DM vs non DM patients.

Association between serum level of C-reactive protein and risk of cardiovascular events based on cohort studies

Although the association between serum level of C-reactive protein (CRP) and risk of cardiovascular events (CVEs) has been reported, the comprehensive assessment of the quantitative association of CRP level with risk of CVEs has not been reported. Our meta-analysis aims to quantitatively evaluate the association of CRP level and risk of CVEs. We searched PubMed and Embase databases for articles published up to December 6, 2019. Studies with data on men and women, different types of CVEs and multiple cohorts within a study were treated as independent studies. Generalized least-squares regression models were used to assess the quantitative association between CRP level and risk of CVEs. Restricted cubic splines were used to model the possible linear association between CRP and CVEs. We included 36 articles (60 studies; 227,715 participants) in the analysis. The pooled relative risks (RRs) of high versus low CRP level for cardiovascular disease (CVD), stroke and coronary heart disease (CHD) were 1.64 (95% confidence interval [CI], 1.49-1.82), 1.46 (95% CI, 1.35-1.58), and 1.55 (95% CI, 1.47-1.63), respectively. A linear association was found between CRP level and CVD (P = 0.429), stroke (P = 0.940), and CHD (P = 0.931); with each 1-mg/L increase in CRP level, the pooled RRs for CVD, stroke, and CHD were 1.18 (95% CI, 1.12-1.24), 1.07 (95% CI, 1.04-1.09), and 1.12 (95% CI, 1.08-1.16), respectively. This meta-analysis suggests that risk of CVEs increases with increasing serum CRP level.

Increased epicardial adipose tissue thickness is associated with microalbuminuria in hypertensive patients with left ventricular hypertrophy

OBJECTIVE

Epicardial adipose tissue (EAT) is a cardiometabolic risk factor, and its possible relationship with hypertension has been previously reported. Microalbuminuria (MA) is associated with target-organ damage, especially in patients with hypertension with left ventricular hypertrophy (LVH) and suggest endothelial dysfunction. This study aimed to investigate the relationship between echocardiographic EAT thickness and presence of MA in patients with hypertension.

METHODS

A total of 297 newly diagnosed hypertension patients who applied to the outpatient clinic were enrolled consecutively in this study. Patients were divided into two groups regarding the presence of LVH in echocardiography. An age and gender matched control group was set including 156 healthy patients without HT. All subjects underwent transthoracic echocardiography for the measurement of EAT thickness. Spot urine samples were collected for the assessment of MA.

RESULTS

In hypertensive patients with LVH, the EAT thicknesses (6.6 ± 1.8 vs 5.3 ± 1.5 vs 5.1 ± 1.3, p < .001; respectively) and prevalence of MA (41.2 vs 20.1 vs 3.2%; p < .001 respectively) were significantly higher than the other two groups. In hypertensive patiens without LVH, no relationship was found between the presence of MA and EAT thickness. In multivariate regression analyses, EAT thickness (OR: 3.141, 95%CI: 2.425-6.123, p < .001) and left ventricular mass index (OR: 1.339, 95%CI: 1.145-2.143, p = .003) were determined as independent predictors for MA development in hypertensive patients with LVH.

CONCLUSION

Measurement of EAT thickness may help to identify high-risk hypertensive patients for target-organ damage especially among patients with LVH.

Evaluation of the Correlation between Serum Concentrations of Asymmetric Dimethylarginine and Corrected TIMI Frame Count in Patients with Slow Coronary Flow

Coronary slow flow (CSF) is an important angiographic entity that is characterized by delayed opacification of coronary arteries in the absence of epicardial occlusive disease. Asymmetric dimethylarginine (ADMA) is an endogenous inhibitor of nitric oxide synthase. Elevated levels of ADMA cause the induction of endothelial dysfunction and thus promote atherosclerosis. This study was aimed at determining the role of ADMA in the development of CSF. One hundred twenty-nine subjects who fulfilled the inclusion criteria were enrolled in this study. According to coronary angiography results, these subjects were divided into five groups. The serum concentration of ADMA was measured in these subjects. In this study, there was no significant correlation between serum concentrations of ADMA and mean corrected TIMI frame count (CTFC) (P > 0.05). However, the ADMA level was significantly correlated with CTFC in the left anterior descending (LAD) coronary artery in patients with CSF (r = −0.381, P = 0.045). Also, plasma ADMA levels were significantly higher in patients with CSF and without CAD compared to patients without CSF and with CAD (50-90%) (P = 0.034). Besides, serum concentrations of ADMA were significantly higher in subjects with BMI < 25 kg/m² compared with those having BMI > 30 kg/m² (P = 0.003). It was also shown that the levels of ADMA were significantly higher in subjects with age as a cardiovascular risk factor compared with those without this risk factor (P = 0.024). Further studies with larger population sizes are needed to confirm the present findings on the association between the serum concentrations of ADMA and CSF.

Evaluation of salivary and serum asymmetric dimethylarginine (ADMA) levels in patients with periodontal and cardiovascular disease as subclinical marker of cardiovascular risk

BACKGROUND

Asymmetric dimethylarginine (ADMA) plays a crucial role in endothelial function and maybe a link for the known interaction of periodontitis and coronary heart disease (CHD). In this pilot study, we compared the impact of gingival health, periodontitis (CP), CHD, or of both diseases (CP + CHD) on salivary and serum ADMA levels.

METHODS

The clinical and periodontal characteristics, serum, and saliva samples were collected from 35 patients with CP, 33 patients with CHD, 35 patients with both CP + CHD, and 35 healthy subjects. Levels of ADMA and C-reactive protein (CRP) were assessed with a commercially available kit.

RESULTS

The median (25% and 75% percentile) concentrations of salivary and serum ADMA were significantly higher in the CHD group [serum: 1.5 (1.2 to 1.8) μmol/L; salivary 1.3 (1 to 1.7) μmol/g protein, P < 0.01] and in the CP + CHD [serum: 1.8 (1.4 to 2.0) μmol/L; salivary 1.5 (1.2 to 1.7) μmol/g protein, P < 0.001] group compared to CP patients and controls. In univariate models, CP (P = 0.034), CHD (P < 0.001), and hs-CRP (P < 0.001) were significantly associated with serum ADMA, whereas in a multivariate model, hs-CRP remained a significant predictor of serum ADMA (P < 0.001). In a multivariate model, the significant predictors of salivary ADMA levels were hs-CRP (P < 0.001) and education socioeconomic status (P = 0.042).

CONCLUSIONS

Patients with CHD and CP + CHD presented higher levels of salivary and serum ADMA compared to healthy subjects and CP patients. hs-CRP was a significant predictor of increased salivary and serum ADMA levels.

Asymmetric Dimethylarginine (ADMA) and Symmetric Dimethylarginine (SDMA) Concentrations in Patients with Obesity and the Risk of Obstructive Sleep Apnea (OSA)

Asymmetric dimethylarginine (ADMA) and symmetric dimethylarginine (SDMA) are endogenous inhibitors of nitric oxide (NO) synthesis, and play a critical role in the process of endothelial dysfunction, and are considered markers of oxidative stress. The aim of the present study was to explore relationships between ADMA and/or SDMA and the occurrence of OSA in obese patients as well as the effect of the endothelial nitric oxide synthase (eNOS) gene polymorphism, which may modify the influence of ADMA or SDMA on NO production. A total of 518 unrelated obese subjects were included in this study. Body weight, height and blood pressure were measured and data on self-reported smoking status were collected. Obstructive sleep apnea (OSA) was assessed by the apnea hypopnea index (AHI). Blood samples were collected to measure serum concentrations of glucose, total cholesterol, LDL-cholesterol, HDL-cholesterol, triglycerides, creatinine, HbA1c (%), folic acid, vitamin B₁₂, C-reactive protein (CRP), aspartate aminotransferase (ASP), alanine aminotransferase (ALT) and IL-6 by routine methods. The NOS3 gene G894T and 4a/4b polymorphisms were detected by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) analysis. ADMA, SDMA and arginine concentrations were assessed simultaneously using liquid chromatography coupled with tandem mass spectrometry (LC-MS/MS) method. Adjusted multivariate logistic regression analysis showed a significant association between the occurrence of OSA and high serum ADMA levels, BMI above 40, age > 43 years, hypertension and male sex. Heterozygotes for the G894T eNOS polymorphism have the lowest serum concentrations of ADMA and SDMA, while no effect of the 4a/4b variants was observed. The results indicate that OSA in obese individuals can coexist with high ADMA levels, which appear as a potential OSA predictor.

Microalbuminuria and Retinopathy among Hypertensive Nondiabetic Patients at a Large Public Outpatient Clinic in Southwestern Uganda

BACKGROUND

Routine testing of microalbuminuria and retinopathy is not done among patients with high blood pressure in resource-limited settings. We determined the prevalence of microalbuminuria and retinopathy and their risk factors among hypertensive patients at a large hospital in western Uganda.

METHODS

We consecutively recruited nondiabetic patients with hypertension at the outpatients' clinic over a period of 3 months. Spot urine samples were tested for urine albumin. Direct fundoscopy was done to assess retinal vasculature and optic disc for signs of hypertensive retinopathy. Logistic regression was done with retinopathy and microalbuminuria as primary outcomes.

RESULTS

We enrolled 334 patients and, of these, 208 (62.3%) were females, with median age of 55 years (range: 25-90). The prevalence of microalbuminuria was 59.3% (95% CI: 50.1-72.2) and that of retinopathy was 66.8% (95% CI: 58.6-76.5). The independent correlates of retinopathy and microalbuminuria were systolic blood pressure (SBP) > 140 mmHg (OR = 2.76, 95% CI: 1.29-5.93) and treatment with beta-blockers (OR = 2.16, 95% CI: 1.05-4.44). Use of ACEIs was unrelated to the study outcomes.

CONCLUSION

The prevalence of retinopathy and microalbuminuria is high. Clinicians should aim for better control of blood pressure and routinely perform fundoscopy and urine albumin, especially for patients with poorly controlled blood pressure.

Circulating asymmetric dimethylarginine and the risk of preeclampsia: a meta-analysis based on 1338 participants

Background

Patients with preeclampsia have higher circulating asymmetric dimethylarginine (ADMA). However, whether circulating ADMA is elevated before the diagnosis of preeclampsia has not been determined.

Methods

A meta-analysis of observational studies that reported circulating ADMA level before the onset of preeclampsia was performed. Pubmed and Embase were searched. Standardized mean differences (SMD) with 95% confidence intervals (CI) were used to estimate the differences in circulating ADMA. A random effect model or a fixed effect model was applied depending on the heterogeneity. The predictive efficacy of circulating ADMA for the incidence of preeclampsia was also explored.

Results

Eleven comparisons with 1338 pregnant women were included. The pooled results showed that the circulating ADMA was significantly higher in women who subsequently developed preeclampsia as compared with those did not (SMD: 0.71, p < 0.001) with a moderate heterogeneity (I² = 43%). Stratified analyses suggested elevation of circulating ADMA is more remarkable in studies with GA of ADMA sampling ≥ 20 weeks (SMD: 0.89, p < 0.01) as compared those with GA of ADMA sampling < 20 weeks (SMD: 0.56, p < 0.01; p for subgroup interaction = 0.03). Differences of maternal age, study design, and ADMA measurement methods did not significantly affect the results. Only two studies evaluated the potential predicting ability of circulating ADMA for subsequent preeclampsia, and retrieved moderate predictive efficacy.

Conclusions

Circulating ADMA is elevated before the development of preeclampsia. Studies are needed to evaluate the predictive efficacy of ADMA for the incidence of preeclampsia.

Asymmetric dimethylarginine and all-cause mortality: a systematic review and meta-analysis

Asymmetrical dimethylarginine (ADMA), an endogenous inhibitor of nitric oxide synthase (NOS), impairs the beneficial effect of NO. The predictive value of ADMA for all-cause mortality remains controversial, though it is important in the development of cardiovascular disease (CVD) and progression to dialysis in renal disease. This systematic review and meta-analysis was conducted to investigate the association between circulating ADMA and all-cause mortality. Studies with data pertinent to the association between circulating ADMA and all-cause mortality were reviewed and OR, HR or RR with 95% CI derived from multivariate Cox's proportional-hazards analysis were extracted. A total of 34 studies reporting 39137 participants were included in final analysis. The results demonstrated that circulating ADMA was independently associated with all-cause mortality (RR = 1.27, 95% CI: 1.20-1.34). The association was still statistically significant in patients with pre-existing renal disease (RR = 1.30, 95% CI: 1.19-1.43) and pre-existing CVD (RR = 1.26, 95% CI: 1.16-1.37). In those without pre-existing renal or CVD, ADMA also predicted all-cause mortality (RR = 1.31, 95% CI: 1.13-1.53). The present study suggests a positive association of circulating ADMA with all-cause mortality. Further studies are needed to investigate the effects of interventions on ADMA, and the value of ADMA as a biomarker.

Increased serum concentrations of asymmetric dimethylarginine (ADMA) in patients with early-onset coronary artery disease

BACKGROUND

Asymmetric dimethylarginine (ADMA) has been associated with an increased risk of cardiovascular disease. We investigated the role of serum ADMA concentrations in early-onset coronary artery disease (EOCAD).

METHODS

Candidates for coronary artery angiography (age<50y for men and <55y for women) who met the inclusion criteria were enrolled in this study. Serum concentrations of ADMA were determined using ELISA. Severity of coronary atherosclerosis was estimated by number of diseased vessels.

RESULTS

A total of 601 subjects (286 with EOCAD patients and 315 controls) were included in the study. ADMA concentrations were found to be significantly higher in the EOCAD group (0.480±0.110μmol/l) than in the control group (0.457±0.091, P=0.007). ADMA concentrations significantly increased with the number of diseased vessels (P<0.001). In addition, serum ADMA concentrations were affected by diabetes mellitus and smoking status, and were positively correlated with serum creatinine and body mass index (BMI).

CONCLUSIONS

Our results show that serum ADMA concentrations were associated with the presence and severity of EOCAD, suggesting that ADMA may be involved in the progression of EOCAD.

Dimethylarginine Dimethylaminohydrolase 2 (DDAH 2) Gene Polymorphism, Asymmetric Dimethylarginine (ADMA) Concentrations, and Risk of Coronary Artery Disease: A Case-Control Study

Asymmetric dimethylarginine (ADMA) has been shown to be an independent predictor of cardiovascular diseases. Dimethylarginine dimethylaminohydrolase 2 (DDAH 2) promotes the metabolism of ADMA and plays a key role in the regulation of acute inflammatory response. With the present study, we investigated the relationship between DDAH 2 polymorphisms and risk of coronary artery disease (CAD) and its association to plasma ADMA concentrations. We used the haplotype-tagging SNP approach to identify tag SNPs in DDAH 2. The SNPs were genotyped by PCR and sequenced in 385 CAD patients and 353 healthy controls. Plasma concentrations of ADMA were determined using enzyme-linked immunosorbent assay (ELISA). A promoter polymorphism −449C/G (rs805305) in DDAH 2 was identified. Compared with the ADMA concentrations in CC genotype (0.328 ± 0.077 μmol/l), ADMA concentrations in CG + GG genotype were significantly increased (0.517 ± 0.090 μmol/l, P < 0.001). No significant associations between the −449C/G and risk of CAD were detected in the genetic models. The results of this study suggest that Genetic −499C/G polymorphism in DDAH 2 gene may affect the plasma ADMA concentrations in patients with CAD. However, it does not indicate a novel genetic risk marker for CAD.

Red cell distribution width and end-organ damage in patients with systo-diastolic hypertension

INTRODUCTION

Both end-organ damage and high red cell distribution width (RDW) values are associated with adverse cardiovascular events, inflammatory status, and neurohumoral activation in hypertensive disease and in the general population. In this study, we investigated the relationship between RDW and end-organ damage in hypertensive patients.

MATERIAL AND METHODS

The 446 systo-diastolic hypertensive patients included in the study received 24-hour ambulatory blood pressure monitoring. Left ventricular mass index, glomerular filtration rate, and microalbuminuria were measured to identify end-organ damage. High-sensitivity C-reactive protein (hs-CRP) and N-terminal pro-B-type natriuretic peptide (NT-proBNP) levels of all patients were also examined.

RESULTS

The mean age of the participants was 49.96 ±11.04 years. The mean RDW was 13.06 ±1.05%. Red cell distribution width was positively correlated with left ventricular myocardial index (LVMI), urinary albumin, hs-CRP, and NT-proBNP (r = 0.298, p < 0.001; r = 0.228, p < 0.001; r = 0.337, p < 0.001; r = 0.277, p < 0.001, respectively), while RDW was negatively correlated with eGFR (r = -0.153, p < 0.001). Additionally, while there was a positive correlation between RDW and 24-h systolic blood pressure, no correlation was found between RDW and 24-h diastolic blood pressure (r = 0.132, p = 0.006 and r = 0.017, p = 0.725, respectively). Multiple linear regression analysis revealed that RDW levels were independently associated with eGFR, LVMI, and severity of albuminuria (β = 0.126, p = 0.010; β = -0.149, p = 0.002; β = 0.114, p = 0.035).

CONCLUSIONS

High RDW levels in systo-diastolic hypertensive patients were found to be an independent predictor of end-organ damage.

Clinical Significance of Endothelial Dysfunction in Essential Hypertension

The endothelium is recognized as a major determinant of vascular physiology and pathophysiology. Over the last few decades, a plethora of studies have implicated endothelial dysfunction in the progression of atherosclerosis and the subclinical target organ damage observed in essential hypertension. However, the clinical significance of diagnosing endothelial dysfunction in patients with essential hypertension remains under investigation. Although a number of vascular and non-vascular markers of endothelial dysfunction have been proposed, there is an ongoing quest for a marker in the clinical setting that is optimal, inexpensive, and reproducible. In addition, endothelial dysfunction emerges as a promising therapeutic target of agents that are readily available in clinical practice. In this context, a better understanding of its role in essential hypertension becomes of great importance. Here, we aim to investigate the clinical significance of endothelial dysfunction in essential hypertension by accumulating novel data on (a) early diagnosis using robust markers with prognostic value in cardiovascular risk prediction, (b) the association of endothelial dysfunction with subclinical vascular organ damage, and (c) potential therapeutic targets.

The relationship of nitric oxide synthesis capacity, oxidative stress, and albumin-to-creatinine ratio in black and white men: the SABPA study

Inadequate substrate availability and increased nitric oxide synthase inhibitor levels attenuate nitric oxide (NO) synthesis, whereas increased vascular oxidative stress may lead to inactivation of NO. We compared markers of NO synthesis capacity and oxidative stress in a bi-ethnic male population. Inter-relationships of ambulatory blood pressure and urinary albumin-to-creatinine ratio with NO synthesis capacity and oxidative stress markers were investigated. NO synthesis capacity markers (L-arginine, asymmetric dimethylarginine (ADMA), and symmetric dimethylarginine (SDMA)) and oxidative stress markers (serum peroxides, total glutathione, glutathione peroxidase (GPx), glutathione reductase (GR), superoxide dismutase (SOD), and catalase) were measured. Black men displayed higher blood pressure and albumin-to-creatinine ratio (all p < 0.001), while NO synthesis capacity was more favorable (higher L-arginine and lower ADMA (p ≤ 0.003)). Antioxidant enzyme activities were similar except for the redox status markers (GR activity and GR/GPx ratio), which were upregulated in black men (p < 0.001). In black men, ADMA was inversely related to GPx activity (R (2) = 0.15; β = -0.20; p = 0.050) and GPx/SOD ratio (R (2) = 0.24; β = -0.37; p < 0.001), but none of these markers related to blood pressure or albumin-to-creatinine ratio. In white men, albumin-to-creatinine ratio was positively associated with ADMA (R (2) = 0.18; β = 0.39; p < 0.001) while ADMA was inversely related to GR activity (R (2) = 0.26; β = -0.29; p = 0.002) and GR/GPx ratio (R (2) = 0.25; β = -0.28; p = 0.003). Black men with elevated blood pressure and albumin-to-creatinine ratio displayed a favorable NO synthesis capacity. This may be counteracted by increased inactivation of NO, although it was not linked to vascular or renal phenotypes. In white men, reduced NO synthesis capacity may lower NO bio-availability, thereby influencing the albumin-to-creatinine ratio.

Microalbuminuria in subjects with hypertension attending specialist blood pressure clinics

Albuminuria is associated with increased risk of cardiovascular disease and target organ damage in patients with diabetes mellitus. In nondiabetic hypertensive patients, the threshold at which microalbuminuria (MAU) increases risk is unclear and there is evidence that cardiovascular risk may be increased in individuals with MAU levels lower than the usual recommended screening thresholds. We compared two definitions of MAU (on the basis of three early morning urine samples) in a cohort of hypertensive patients attending two specialist clinics in Scotland: conventional (MAU(C)) albumin-to-creatinine ratio (ACR) >2.5-25 mg mmol(-1) in males or >3.5-25 mg mmol(-1) in females; and low-grade (MAU(L)) ACR 1.2-2.5 in males or 1.7-3.5 mg mmol(-1) in females. Of the 1059 subjects screened, 786 (74%) were nondiabetic, with estimated glomerular filtration rate ⩾30 ml min(-1) per 1.73 m(2) and without gross proteinuria (low-risk subset). The average age was 58±15 years, body mass index 30±6 kg m(-2) and 46% were males. The prevalence of MAU(C) was 11% and 9.5% in the overall and low-risk subset, respectively, whereas MAU(L) prevalence was 11.1% and 10% respectively. The prevalence of cardiovascular disease was higher (24%) with albuminuria (both MAU(C) and MAU(L)) compared with 14% among those without albuminuria. The use of MAU(L) doubled the number of hypertensive subjects with increased cardiovascular risk who can be targeted for more rigorous risk reduction strategies. Consideration should be given to reducing the current threshold for MAU.

Nitric oxide synthesis capacity, ambulatory blood pressure and end organ damage in a black and white population: the SABPA study

Nitric oxide (NO) synthesis capacity is determined by the availability of substrate(s) such as L-arginine and the influence of nitric oxide synthase (NOS) inhibitors, asymmetric dimethylarginine (ADMA) and symmetric dimethylarginine (SDMA). These factors may be important in black South Africans with a very high prevalence of hypertension. We compared ambulatory blood pressure (BP), markers of end organ damage and NO synthesis capacity markers [L-arginine, L-homoarginine, L-citrulline, L-arginine:ADMA, ADMA, SDMA and dimethylarginine (DMA)], between black and white teachers (n = 390). Associations of nighttime BP and markers of end organ damage with NO synthesis capacity markers were also investigated. Although black men and women had higher BP and albumin-to-creatinine ratio (ACR) (all p < 0.001), they also had higher L-arginine, L-homoarginine, L-arginine:ADMA and lower SDMA and DMA levels (all p < 0.05). Only in white men ADMA concentrations associated positively with nighttime systolic blood pressure (R (2) = 0.20, β = 0.26, p = 0.009), nighttime diastolic blood pressure (R (2) = 0.23, β = 0.27, p = 0.007), carotid intima media thickness (cIMT) (R (2) = 0.36, β = 0.22, p = 0.008) and ACR (R (2) = 0.14, β = 0.32, p = 0.001). Our findings suggest that despite an adverse cardiovascular profile in blacks, their NO synthesis capacity profile seems favourable, and that other factors, such as NO inactivation, may prove to be more important.

Prevalence and associated factors of silent brain infarcts in a Mediterranean cohort of hypertensives

Silent brain infarcts (SBIs) are detected by neuroimaging in approximately 20% of elderly patients in population-based studies. Limited evidence is available for hypertensives at low cardiovascular risk countries. Investigating Silent Strokes in Hypertensives: a Magnetic Resonance Imaging Study (ISSYS) is aimed to assess the prevalence and risk factors of SBIs in a hypertensive Mediterranean population. This is a cohort study in randomly selected hypertensives, aged 50 to 70 years old, and free of clinical stroke and dementia. On baseline, all participants underwent a brain magnetic resonance imaging to assess prevalence and location of silent infarcts, and data on vascular risk factors, comorbidities, and the presence of subclinical cardiorenal damage (left ventricular hypertrophy and microalbuminuria) were collected. Multivariate analyses were performed to determine SBIs associated factors. A total of 976 patients (49.4% men, mean age 64 years) were enrolled, and 163 SBIs were detected in 99 participants (prevalence 10.1%; 95% CI, 8.4%-12.2%), most of them (64.4%) located in the basal ganglia and subcortical white matter. After adjustment, besides age and sex, microalbuminuria and increasing total cardiovascular risk (assessed by the Framingham-calibrated for Spanish population risk function) were independently associated with SBIs. Male sex increased the odds of having SBIs in 2.5 as compared with females. Our results highlight the importance of considering both global risk assessment and sex differences in hypertension and may be useful to design future preventive interventions of stroke and dementia.

The role of nutrition and nutraceutical supplements in the treatment of hypertension

Vascular biology, endothelial and vascular smooth muscle and cardiac dysfunction play a primary role in the initiation and perpetuation of hypertension, cardiovascular disease and target organ damage. Nutrient-gene interactions and epigenetics are predominant factors in promoting beneficial or detrimental effects in cardiovascular health and hypertension. Macronutrients and micronutrients can prevent, control and treat hypertension through numerous mechanisms related to vascular biology. Oxidative stress, inflammation and autoimmune dysfunction initiate and propagate hypertension and cardiovascular disease. There is a role for the selected use of single and component nutraceutical supplements, vitamins, antioxidants and minerals in the treatment of hypertension based on scientifically controlled studies which complement optimal nutrition, coupled with other lifestyle modifications.

Cystatin C, CRP, log TG/HDLc and metabolic syndrome are associated with microalbuminuria in hypertension

BACKGROUND

In patients with systemic hypertension, microalbuminuria is a marker of endothelial damage and is associated with an increased risk for cardiovascular disease.

OBJECTIVE

To determine the factors that may lead to the occurrence of microalbuminuria in hypertensive patients with serum creatinine lower than 1.5 mg/dL.

METHODS

This cross-sectional study included 133 Brazilians with essential hypertension followed up at a hypertension outpatient clinic. Those with serum creatinine higher than 1.5 mg/dL, as well as those with diabetes mellitus, were excluded. Systolic and diastolic blood pressures were measured, and body mass index (BMI) and GFR estimated by using the CKD-EPI formula were calculated. The serum levels of the following were assessed: CysC, creatinine, total cholesterol, HDL cholesterol, LDL cholesterol, triglycerides, C-reactive protein (CRP) and fasting glucose. Microalbuminuria was determined in 24-hour urine. Hypertensive patients were classified according to the presence of one or more criteria for metabolic syndrome.

RESULTS

In a multiple regression analysis, the serum levels of CysC and CRP, the atherogenic index log TG/HDLc and the presence of three or more criteria for metabolic syndrome were positively correlated with microalbuminuria (r2: 0.277, p < 0.05).

CONCLUSION

CysC, CRP, log TG/HDLc, and the presence of three or more criteria for metabolic syndrome, regardless of serum creatinine, were associated with microalbuminuria, an early marker of kidney damage and cardiovascular risk in patients with essential hypertension.

Association between serum ferritin and microalbuminuria in Type 2 diabetes in Taiwan

AIMS

Serum ferritin has been found closely related with diabetes and glucose metabolism, but its impact on diabetic nephropathy remains unknown. This study aimed to explore the association between serum ferritin and microalbuminuria in Type 2 diabetes.

METHODS

Eight hundred and fifty-one subjects with Type 2 diabetes were selected from a cohort participating in a glycaemic control study in Taiwan in 2008. We used urine albumin:creatinine ratio to define microalbuminuria; serum ferritin was divided into quartiles for analysis. Logistic regression and trend tests were used to delineate the association between serum ferritin and microalbuminuria.

RESULTS

Subjects with diabetes with higher ferritin tended to have more metabolic disorders, higher high-sensitivity C-reactive protein and higher prevalence of microalbuminuria. Compared with those in the lowest quartile, subjects with diabetes in the highest ferritin quartile were 55% (P = 0.029) more likely to have microalbuminuria. After controlling for demographics, metabolic profiles and other inflammatory markers, the association between serum ferritin levels and microalbuminuria remained significant (P for trend < 0.001). This independent relationship was not changed either for those who had better glycaemic control or those who had not used an angiotensin-converting enzyme inhibitor or angiotensin receptor blocker.

CONCLUSIONS

The current study shows hyperferritinemia may be an independent risk factor of nephropathy in patients with Type 2 diabetes.

Changes in biomarkers associated with living kidney donation

Living donor kidneys have been associated with better graft and overall survival in kidney transplant recipients. Although a living kidney donation is generally considered safe in carefully selected living donors, concerns of possible adverse effects related to kidney donation remain, especially in younger and high-risk donors. In this study, we examined the changes in a panel of traditional and novel serum biomarkers linked with cardiovascular conditions in a cohort of 34 healthy living kidney donors with a mean age ± SD of 40 ± 10 years and estimated predonation glomerular filtration rate (GFR) of 86 ± 10 ml/min/1.73 m(2). At 6 months after donation, there were no significant changes in the clinical parameters including body mass index and blood pressure despite a significant decline in the mean estimated GFR to 60 ml/min/1.73 m(2). Among the panel of markers, the levels of symmetric dimethylarginine and fibroblast growth factor 23 increased significantly compared to baseline, suggesting that living kidney donation may result in changes in biomarkers that are associated with cardiovascular risk in other cohorts.

Preclinical cardiorenal interrelationships in essential hypertension

A diseased heart causes numerous adverse effects on kidney function, and vice versa renal disease can significantly impair cardiac function. Beyond these heart-kidney interrelationships at the clinical level, a reciprocal association has been suggested to exist even in the early stages of those organs' dysfunction. The aim of the present review is to provide evidence of the presence of a preclinical cardiorenal syndrome in the particular setting of essential hypertension, focusing on the subsequent hypertensive sequelae on heart and kidneys. In particular, a plethora of studies have demonstrated not only the predictive role of kidney damage, as expressed by either decreased glomerular filtration or increased urine albumin excretion, for adverse left ventricular functional and structural adaptations but also preclinical heart disease, i.e. left ventricular hypertrophy that is associated with deterioration of renal function. Notably, these reciprocal interactions seem to exist even at the level of microcirculation, since both coronary flow reserve and renal hemodynamics are strongly related with clinical and preclinical renal and cardiac damage, respectively. In this preclinical setting, common pathophysiological denominators, including the increased hemodynamic load, sympathetic and renin-angiotensin system overactivity, increased subclinical inflammatory reaction, and endothelial dysfunction, account not only for the reported associations between overt cardiac and renal damage but also for the parallel changes that occur in coronary and renal microcirculation.

Influence of urine creatinine concentrations on the relation of albumin-creatinine ratio with cardiovascular disease events: the Multi-Ethnic Study of Atherosclerosis (MESA)

BACKGROUND

Higher urine albumin-creatinine ratio (ACR) is associated with cardiovascular disease (CVD) events, an association that is stronger than that between spot urine albumin on its own and CVD. Urine creatinine excretion is correlated with muscle mass, and low muscle mass also is associated with CVD. Whether low urine creatinine concentration in the denominator of the ACR contributes to the association of ACR with CVD is uncertain.

STUDY DESIGN

Prospective cohort study.

SETTING & PARTICIPANTS

6,770 community-living individuals without CVD.

PREDICTORS

Spot urine albumin concentration, the reciprocal of the urine creatinine concentration (1/UCr), and ACR.

OUTCOME

Incident CVD events.

RESULTS

During a mean of 7.1 years of follow-up, 281 CVD events occurred. Geometric mean values for spot urine creatinine concentration, urine albumin concentration, and ACR were 95 ± 2 (SD) mg/dL, 0.7 ± 3.7 mg/dL, and 7.0 ± 3.1 mg/g. Urine creatinine concentration was lower in older, female, and low-weight individuals. Adjusted HRs per 2-fold higher increment in each urinary measure with CVD events were similar (1/UCr: 1.07 [95% CI, 0.94-1.22]; urine albumin concentration: 1.08 [95% CI, 1.01-1.14]; and ACR: 1.11 [95% CI, 1.04-1.18]). ACR ≥10 mg/g was associated more strongly with CVD events in individuals with low weight (HR for lowest vs highest tertile: 4.34 vs 1.97; P for interaction = 0.006). Low weight also modified the association of urine albumin concentration with CVD (P for interaction = 0.06), but 1/UCr did not (P for interaction = 0.9).

LIMITATIONS

We lacked 24-hour urine data.

CONCLUSIONS

Although ACR is associated more strongly with CVD events in persons with low body weight, this association is not driven by differences in spot urine creatinine concentration. Overall, the associations of ACR with CVD events appear to be driven primarily by urine albumin concentration and less by urine creatinine concentration.

Soluble receptor for advanced glycation end-product levels are related to albuminuria and arterial stiffness in essential hypertension

BACKGROUND AND AIMS

Emerging evidence suggests that the soluble receptor for advanced glycation end-products (sRAGE) is implicated in the development of vascular disease. We investigated the interrelationships of sRAGE with albumin to creatinine ratio (ACR) and arterial stiffness in essential hypertension.

METHODS AND RESULTS

In 309 untreated non-diabetic hypertensives, ACR values were determined as the mean of three non-consecutive morning spot urine samples and aortic stiffness was evaluated on the basis of carotid to femoral pulse wave velocity (c-f PWV). In all subjects, venous blood sampling was performed for the estimation of sRAGE levels. Patients with low (n = 155) compared to those with high sRAGE values (n = 154) had greater 24-h systolic BP (140 ± 8 vs. 134 ± 7 mmHg, p < 0.0001), exhibited higher ACR (36.3 ± 51.6 vs. 17.2 ± 1.2 mg g(-1), p < 0.0001) and c-f PWV (8.3 ± 1.5 vs. 7.8 ± 1.1 m s(-1), p = 0.003), independently of confounding factors. Multiple regression analyses revealed that age, male sex, 24-h systolic BP and sRAGE were the 'independent correlates' of ACR (R(2) = 0.493, p < 0.0001), while age, 24-h systolic BP and sRAGE were the 'independent correlates' of c-f PWV (R(2) = 0.428, p < 0.0001).

CONCLUSION

In hypertensives, decreased sRAGE levels are accompanied by pronounced albuminuria and arterial stiffening. The association of sRAGE with ACR and c-f PWV suggests involvement of sRAGE in the progression of hypertensive vascular damage.

Left ventricular mass index as a predictor of new-onset microalbuminuria in hypertensive subjects: a prospective study

BACKGROUND

We aimed to investigate the predictive role of left ventricular mass and its reduction on the development of new-onset microalbuminuria (MA) in newly diagnosed hypertensive patients.

METHODS

A total of 207 nondiabetic, normoalbuminuric patients without clinical organ damage (aged 50.8 ± 10.1 years, 132 male, 84 smokers) with baseline office blood pressure (BP) 148/96 mm Hg were followed for a mean period of 3.3 ± 1.3 years. At baseline and last follow-up visit, all patients underwent office and 24-h ambulatory BP monitoring, albumin to creatinine ratio (ACR) determination, and echocardiographic assessment of left ventricular mass index (LVMI). All patients were treated with antihypertensive therapy during the follow-up period. We defined MA as ACR between 20 and 300 mg/g for men and 30-300 mg/g for women, effective BP control as office BP <140/90 mm Hg in ≥75% of total number of visits, and LVMI reduction as the decline of LVMI at end-follow-up of ≥15% with respect to the baseline value.

RESULTS

Between baseline and last follow-up visit, LVMI decreased by 6.84 ± 21.5 g/m(2) (P < 0.01); 64.3% (n = 133) of participants achieved BP control during the follow-up period. Of the total population, 5.8% (n = 12) developed MA during follow-up. Cox-regression analysis, after adjustment for clinical variables, revealed that increase of LVMI by 1 s.d. (23.3 g/m(2)) conferred a 15% increased risk of new-onset MA, while LVMI reduction and BP control were both associated with almost 100% reduced risk of MA development.

CONCLUSIONS

LVMI and its reduction were qualified as predictors of new-onset MA in newly diagnosed hypertensive patients, beyond BP control.

Dietary salt intake is related to inflammation and albuminuria in primary hypertensive patients

BACKGROUND/OBJECTIVES

In this study, we hypothesized that dietary salt intake may be related with inflammation and albuminuria independently from blood pressure (BP) in non-diabetic hypertensive patients.

SUBJECTS/METHODS

A total of 224 patients with primary hypertension were included in the study. Serum C-reactive protein (CRP) levels, 24-h urine sodium and albumin excretion were measured in all patients. The subjects were divided into tertiles according to the level of 24-h urinary sodium excretion: low-salt-intake group (n = 76, mean urine sodium: 111.7 ± 29.1 mmol/24 h), medium-salt-intake group (n = 77, mean urine sodium: 166.1 ± 16.3 mmol/24 h) and high-salt-intake group (n = 71, mean urine sodium: 263.6 ± 68.3 mmol/24 h).

RESULTS

Systolic and diastolic BP measurements of patients were similar in the three salt-intake groups. CRP and urinary albumin levels were significantly higher in high-salt-intake group compared with medium- and low-salt-intake groups (P = 0.0003 and P = 0.001, respectively). CRP was positively correlated with 24-h urinary sodium excretion (r = 0.28, P = 0.0008) and albuminuria, whereas albuminuria was positively correlated with 24-h urinary sodium excretion (r = 0.21, P = 0.0002). Multiple regression analysis revealed that urinary sodium excretion was an independent predictor of both CRP and albuminuria.

CONCLUSIONS

These findings suggest that high salt intake is associated with enhanced inflammation and target organ damage reflected by increased albuminuria in treated hypertensive patients independent of any BP effect.

Polymorphisms in LEP and NPY genes modify the response to soluble fibre Plantago ovata husk intake on cardiovascular risk biomarkers

The satiating effect of fibre consumption has been related to gut hormones, such as peptide YY and leptin. These peptides may also influence cardiovascular (CVD) risk biomarkers. Nevertheless, there is wide interindividual variation in metabolic responses to fibre consumption. The objective was to investigate differences in the effects of soluble fibre, in the form of Plantago ovata husk (Po-husk) treatment, on CVD risk biomarkers according to selected polymorphisms in genes related to satiety. The study was a multi-centred, double-blind, placebo-controlled, parallel and randomised trial in mild-moderate hypercholesterolaemic patients (age range: 43-67 years). Eight polymorphisms in three genes related to satiety (LEP, NPY and PYY) were identified in 178 participants; 88 patients in the placebo (microcrystalline cellulose 14 g/day) group and 90 in the Po-husk (14 g/day) group, which had added to a low-saturated-fat diet for 8 weeks. The CVD biomarkers measured included the following: lipid profile, blood pressure (BP), glucose, insulin, hs-CRP, oxidised LDL and IL-6. Relative to the placebo, Po-husk consumption lowered the plasma total cholesterol concentration by 3.3 % according to rs7799039 polymorphism in the LEP gene (p < 0.05). Furthermore, the Po-husk reduced systolic BP (mean [95 % CI]) by -8 mmHg (-14.16; -1.90) and hs-CRP by 24.9 % in subjects with the AA genotype of the rs16147 polymorphism in the NPY gene (32 % of our total population; p < 0.05), which remained significant after Bonferroni correction. In conclusion, polymorphisms in the LEP and NPY genes potentiate the response to Po-husk, particularly the effects on systolic BP and the hs-CRP plasma concentration.

G501C polymorphism of the oxidized LDL receptor gene is associated with albuminuria in Chinese essential hypertension patients

Albuminuria is an independent predictor of renal and cardiovascular complications in hypertensive subjects. We previously showed that lectin-like oxidized low density lipoprotein receptor 1 (OLR-1) polymorphisms at G501C are associated with susceptibility to essential hypertension and serum C-reactive protein levels. We have now investigated a possible association between OLR-1 polymorphisms at G501C, genotyped by PCR-RFLP, and severity of albuminuria in 307 hypertensive Chinese subjects and 225 age- and sex-matched controls. Urine albumin concentration /urine creatinine concentrations (ACR) were measured to evaluate the severity of albuminuria. Hypertensive subjects had a significantly higher frequency of the CC genotype and the C allele of the OLR-1 polymorphism than controls; this was also true for . hypertensive subjects with macroalbuinuria and microalbuminuria compared to those with normoalbuminuria. The mean ACR levels and mean serum C-reactive protein levels in CC carriers were significantly higher than in GG and GC carriers. There was a significant, positive correlation between serum hs-C-reactive protein levels and ACR levels. We conclude that OLR-1 polymorphisms at G501C affect the severity of albuminuria in essential hypertension patients.

Biomarkers in chronic kidney disease: a review

Chronic kidney disease (CKD) is a major public health problem. The classification of CKD by KDOQI and KDIGO and the routine eGFR reporting have resulted in increased identification of CKD. It is important to be able to identify those at high risk of CKD progression and its associated cardiovascular disease (CVD). Proteinuria is the most sensitive marker of CKD progression in clinical practice, especially when combined with eGFR, but these have limitations. Hence, early, more sensitive, biomarkers are required. Recently, promising biomarkers have been identified for CKD progression and its associated CVD morbidity and mortality. These may be more sensitive biomarkers of kidney function, the underlying pathophysiological processes, and/or cardiovascular risk. Although there are some common pathways to CKD progression, there are many primary causes, each with its own specific pathophysiological mechanism. Hence, a panel measuring multiple biomarkers including disease-specific biomarkers may be required. Large, longitudinal observational studies are needed to validate candidate biomarkers in a broad range of populations prior to implementation into routine CKD management. Recent renal biomarkers discovered include neutrophil gelatinase-associated lipocalin, kidney injury molecule-1, and liver-type fatty acid-binding protein. Although none are ready for use in clinical practice, it is timely to review the role of such biomarkers in predicting CKD progression and/or CVD risk in CKD.

Inflammation and asymmetric dimethylarginine for predicting death and cardiovascular events in ESRD patients

BACKGROUND

Endothelial dysfunction as assessed by asymmetric dimethylarginine (ADMA) and inflammation has been consistently linked to atherosclerosis, death, and cardiovascular (CV) events in ESRD patients. Inflammation amplifies the effect of ADMA on the severity of atherosclerosis in ESRD patients, but it is still unknown whether inflammation and ADMA interact in the high risk of death and CV events in this population.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

In a cohort of 225 hemodialysis patients, we investigated the interaction between inflammatory biomarkers (C-reactive protein and IL-6) and ADMA as predictors of death and CV events over an extended follow-up (13 years).

RESULTS

During follow-up, 160 patients died, and 123 had CV events. With crude and multiple Cox regression analyses, an interaction was found between inflammation biomarkers and ADMA for explaining death and CV events in ESRD patients. The adjusted hazard ratios (HRs) for death (HR, 2.18; 95% confidence interval [CI], 1.34 to 3.54) and CV outcomes (HR, 2.59; 95% CI, 1.47 to 4.55) of patients with C-reactive protein and ADMA above the median were higher than expected in the absence of interaction under the additive model (1.15 and 1.97, respectively) and significantly higher than in patients with only one biomarker above the median. Data analyses carried out by stratifying patients according to IL-6 provided similar results.

CONCLUSIONS

These data support the hypothesis that inflammation amplifies the risk of death and CV events associated with high ADMA levels in ESRD. These analyses further emphasize the need for intervention studies to attenuate inflammation and high ADMA levels in this population.

Periodontitis and blood pressure: the concept of dental hypertension

Chronic periodontitis is a common inflammatory disorder that is being contemplated as a risk factor for atherosclerotic complications. Current epidemiological evidence also supports its potential association with increases in blood pressure levels and hypertension prevalence. Furthermore, data from cross-sectional studies suggest that in hypertensive subjects periodontitis may enhance the risk and degree of target organ damage. A possible pathogenetic background of an effect of periodontitis on blood pressure should include the systemic generalization of the local oral inflammation, the role of the host immune response, the direct microbial effect on the vascular system and alterations in endothelial function. Inversely, the concept of hypertension unfavorably affecting periodontal tissues cannot be excluded. The two conditions share multiple common risk factors that should be readily controlled for when assessing a possible association. Thoroughly designed prospective and interventional trials are needed in order to determine the impact of periodontitis on blood pressure regulation and incident hypertension and its integration in the clinical approach of both dental and hypertensive patients.

Relationship between mean platelet volume levels and subclinical target organ damage in newly diagnosed hypertensive patients

BACKGROUND

Significant numbers of asymptomatic hypertensive patients are attacked by subclinical target organ damage (TOD) such as proteinuria, left ventricular hypertrophy and carotid atherosclerosis. Platelets become activated in uncontrolled hypertension and play a crucial role in increased thrombotic tendency. Mean platelet volume (MPV) is one of the markers that correlate closely with platelet activity. We aimed to investigate the relationship between MPV levels and subclinical TOD in newly diagnosed hypertensive patients.

METHODS

80 newly diagnosed hypertensive patients were enrolled to this cross-sectional study. Ambulatory blood pressure monitoring was performed for all patients. Left ventricular mass index (LVMI), carotid intima-media thickness (IMT) and urine albumin/creatinine ratio (UACR) were measured as indices of cardiac, vascular and renal damage, respectively. MPV was measured from blood samples collected in EDTA tubes and high-sensitivity C reactive protein (hs-CRP) was measured by using nephlometer.

RESULTS

MPV was significantly correlated with 24-h systolic-diastolic blood pressure (r = 0.52 and r = 0.55, respectively). Correlation analysis indicated that MPV was moderately related with UACR, LVMI, carotid IMT and hs-CRP (r = 0.50, r = 0.55, r = 0.60 and r = 0.69, respectively, p = 0.0001). Multivariable analysis identified that MPV levels were independently associated with severity of proteinuria, carotid IMT and LVMI (p = 0.001).

CONCLUSION

Our findings suggested that MPV levels were associated with severity of subclinical TOD including; carotid atherosclerosis, left ventricular hypertrophy and renal damage, in hypertensive patients. In addition to this, MPV levels were significantly correlated with hs-CRP levels and 24-h ambulatory blood pressure measurements.