The association of microalbuminuria with aortic stiffness is independent of C-reactive protein in essential hypertension

Urinary N-Acetyl-β-d-Glucosaminidase (NAG) Levels and Risk of Cardiovascular Events in Diabetic Patients

BACKGROUND

Cardiovascular diseases (CVDs) have a high incidence rate in population with diabetic patients. Studies on the association between urinary N-acetyl-β-d-glucosaminidase (NAG) levels, the biomarker of renal tubular damage, with cardiovascular (CV) events diabetic patients was still few.

METHODS

The relationship between urinary NAG levels and CV events was analyzed in a prospective cohort including 357 patients with type 2 diabetes mellitus at a follow-up of 5 years.

RESULTS

Twenty-six (7.3%) patients have CV events. Kaplan-Meier analysis suggested that diabetic patients with urine NAG levels ≥37.5 IU/L had a higher rate of CV events than those with urine NAG levels <37.5 IU/L (Log rank test, P = 0.021). Cox analysis revealed that elevated urine NAG levels significantly contributed to increased risk of CV events (HR = 1.43, 95% CI 1.23-1.93, P < 0.001) after adjusting for clinical confounding factors. Interestingly, we also found that "abnormal renal function" has an effect modification on the association between urine NAG levels and CV events. ROC-AUC analysis suggested that the urine NAG (AUC = 0.81, P < 0.001) had a better predictive value than eGFR (AUC = 0.74, P = 0.012).

CONCLUSION

Elevated urine NAG levels are associated with higher risk of CV events in patients with type 2 diabetes. These results might further suggested that urinary NAG is a value urinary biomarker for early detecting CV events among diabetic patients.

Hypoadiponectinemia is associated with aortic stiffness in nondialysis diabetic patients with stage 3-5 chronic kidney disease

OBJECTIVES

Albuminuria and serum adiponectin levels are factors that have been associated with the development of cardiovascular disease in patients with diabetes mellitus. Here we investigated the relationship between serum adiponectin levels and aortic stiffness in nondialysis diabetic kidney disease patients with stage 3-5 chronic kidney disease.

METHODS

Fasting blood samples were obtained from 80 nondialysis diabetic kidney disease patients with stage 3-5 chronic kidney disease. Carotid-femoral pulse wave velocity (cfPWV) was measured using applanation tonometry; cfPWV values of >10 m/s were defined as aortic stiffness. Serum adiponectin levels were determined by enzyme immunoassay.

RESULTS

Forty-two patients (52.5%) with nondialysis diabetic kidney disease were diagnosed with aortic stiffness. The patients in this group were older (p = 0.011), had higher systolic blood pressure (p = 0.002) and urine albumin-to-creatinine ratios (p = 0.013), included fewer females (p = 0.024), and had lower serum adiponectin (p = 0.001) levels than those in the control group. Multivariable logistic regression analysis revealed that serum adiponectin was independently associated with aortic stiffness (odds ratio = 0.930, 95% confidence interval: 0.884-0.978, p = 0.005) and also positively correlated with cfPWV values by multivariable linear regression (β = -0.309, p = 0.002) in nondialysis diabetic kidney disease patients.

CONCLUSIONS

The results suggested that serum adiponectin levels could be used to predict aortic stiffness in nondialysis diabetic kidney disease patients with stage 3-5 chronic kidney disease.

Urine albumin-to-creatinine ratio and asymptomatic intracranial atherosclerotic stenosis in hypertensive patients

Intracranial atherosclerotic stenosis (ICAS) contributes to nearly 50% of stroke in China, especially in patients with hypertension. Urine albumin-to-creatinine ratio (ACR) has been related to stroke and other atherosclerotic cardiovascular diseases. However, there is limited information about the association of ACR and early impairment of cerebral vessels. Hereby we assessed the association of ICAS with ACR, estimated glomerular filtration rate (eGFR), and dipstick proteinuria in a stroke-free hypertensive population. We included 889 hypertension patients aged ≥60 years without prior stroke. Computed tomography angiography was performed to detect ICAS. ACR and dipstick proteinuria were tested from a random spot urine. eGFR was calculated using the CKD-EPI equation. Logistic regression was carried out to analyze the association of renal function with the presence, extent, and lesion number of ICAS. Elevated ACR (≥30 mg/g) was associated with ICAS after adjustment of confounding factors (odds ratio (OR) = 1.66, 95% confidence interval (CI): 1.21-2.29). Patients with elevated ACR were more prone to develop moderate-to-severe stenosis (OR = 1.57, 95% CI: 1.16-2.14) and more lesions (OR = 1.58, 95% CI: 1.16-2.15). Such association was independent of previously identified cardiovascular risk factors. No significant association was detected between ICAS and dipstick proteinuria or eGFR after adjustment. Our findings suggested that elevated ACR was associated with asymptomatic ICAS in an aged stroke-free hypertensive population.

Serum osteocalcin level as an indicator of low-grade albuminuria in Chinese men free of kidney disease

OBJECTIVE

The presence of low-grade albuminuria (LGA) suggested that the pathophysiology of vascular dysfunction has been initiated. Clear evidence supports a role for osteocalcin in energy metabolism and a great incidence of pathological cardiovascular changes. The observational community-based study aims to examine the association of osteocalcin with LGA, which may provide new insight into potential involvement of osteocalcin in cardiovascular diseases.

METHODS

A total of 1951 adults [58.37 (53.34-63.13) years, 41.3% men] from Shanghai were enrolled. LGA was defined as a urinary albumin-to-creatinine ratio (UACR) < 30 mg/g. Serum osteocalcin was measured using an electrochemiluminescence immunoassay.

RESULTS

Serum osteocalcin level in men decreased with increasing UACR after adjusting for potential covariates (p = 0.045); however, the adjusted association disappeared in women (p = 0.258). Linear regression analysis showed that osteocalcin was a negative variable of UACR in men (standardized β = -0.074, p = 0.030), particularly prominent in non-hyperglycemic, non-hypertensive men, even regardless of estimated glomerular filtration rate (eGFR) (60 ≤ eGFR <90 mL/min/1.73 m², standardized β =-0.422, p = 0.004; ≥ 90 mL/min/1.73 m², standardized β = -0.167, p = 0.037).

CONCLUSION

After controlling for confounders, serum osteocalcin level was independently associated with LGA in men, which suggested that osteocalcin was closely related with atherosclerosis and vascular dysfunction.

The renal tubular damage marker urinary N-acetyl-β-D-glucosaminidase may be more closely associated with early detection of atherosclerosis than the glomerular damage marker albuminuria in patients with type 2 diabetes

Background

To determine the association between urinary N-acetyl-β-d-glucosaminidase (NAG), a marker of renal tubulopathy, and carotid intima-media thickness (IMT) and plaques in patients with type 2 diabetes mellitus (T2D) and to compare the predictive value of NAG versus albuminuria, a marker of renal glomerulopathy.

Methods

A total of 343 participants were enrolled in this retrospective cross-sectional study. We recruited participants with T2D who were tested for blood glucose parameters, urinary NAG, and urinary albumin-to-creatinine ratio (ACR) and had been checked for carotid ultrasonography.

Results

We classified participants into a below-median urinary NAG group (Group I; n = 172) or an above-median group (Group II; n = 171). Mean, maximum, and mean of maximum carotid IMT and the proportion of patients with carotid plaques were significantly higher in Group II compared with Group I. In multiple linear regression analyses, high urinary NAG (Group II) was significantly associated with carotid IMT, independently of urinary ACR and other confounding factors. In terms of carotid plaques, both urinary NAG and ACR were significantly higher in participants with carotid plaques than in those without carotid plaques. After adjustment for confounding factors, both urinary NAG and ACR were significantly associated with the presence of carotid plaques.

Conclusions

Elevated urinary NAG, a marker of renal tubular damage, was related to increased carotid IMT and the presence of carotid plaques in patients with T2D. Urinary NAG may be a more sensitive biomarker than urinary albumin for early detection of atherosclerosis.

Electronic supplementary material

The online version of this article (doi:10.1186/s12933-017-0497-7) contains supplementary material, which is available to authorized users.

Subclinical Kidney Damage in Hypertensive Patients: A Renal Window Opened on the Cardiovascular System. Focus on Microalbuminuria

The kidney is one of the major target organs of hypertension.Kidney damage represents a frequent event in the course of hypertension and arterial hypertension is one of the leading causes of end-stage renal disease (ESRD).ESRD has long been recognized as a strong predictor of cardiovascular (CV) morbidity and mortality. However, over the past 20 years a large and consistent body of evidence has been produced suggesting that CV risk progressively increases as the estimated glomerular filtration rate (eGFR) declines and is already significantly elevated even in the earliest stages of renal damage. Data was supported by the very large collaborative meta-analysis of the Chronic Kidney Disease Prognosis Consortium, which provided undisputable evidence that there is an inverse association between eGFR and CV risk. It is important to remember that in evaluating CV disease using renal parameters, GFR should be assessed simultaneously with albuminuria.Indeed, data from the same meta-analysis indicate that also increased urinary albumin levels or proteinuria carry an increased risk of all-cause and CV mortality. Thus, lower eGFR and higher urinary albumin values are not only predictors of progressive kidney failure, but also of all-cause and CV mortality, independent of each other and of traditional CV risk factors.Although subjects with ESRD are at the highest risk of CV diseases, there will likely be more events in subjects with mil-to-moderate renal dysfunction, because of its much higher prevalence.These findings are even more noteworthy when one considers that a mild reduction in renal function is very common in hypertensive patients.The current European Society of Hypertension (ESH)/European Society of Cardiology (ESC) guidelines for the management of arterial hypertension recommend to sought in every patient signs of subclinical (or asymptomatic) renal damage. This was defined by the detection of eGFR between 30 mL/min/1.73 m² and 60 mL/min/1.73 m² or the presence of microalbuminuria (MAU), that is an amount of albumin in the urine of 30-300 mg/day or an albumin/creatinine ratio, preferentially on morning spot urine, of 30-300 mg/g.There is clear evidence that urinary albumin excretion levels, even below the cut-off values used to define MAU, are associated with an increased risk of CV events. The relationships of MAU with a variety of risk factors, such as blood pressure, diabetes and metabolic syndrome and with several indices of subclinical organ damage, may contribute, at least in part, to explain the enhanced CV risk conferred by MAU. Nonetheless, several studies showed that the association between MAU and CV disease remains when all these risk factors are taken into account in multivariate analyses. Therefore, the exact pathophysiological mechanisms explaining the association between MAU and CV risk remain to be elucidated. The simple search for MAU and in general of subclinical renal involvement in hypertensive patients may enable the clinician to better assess absolute CV risk, and its identification may induce physicians to encourage patients to make healthy lifestyle changes and perhaps would prompt to more aggressive modification of standard CV risk factors.

Twelve-week randomized study to compare the effect of vildagliptin vs. glibenclamide both added-on to metformin on endothelium function in patients with type 2 diabetes and hypertension

BACKGROUND

Vildagliptin, a DPP-4 inhibitor widely used for the treatment of type 2 diabetes mellitus (T2DM), shows beneficial effects on endothelial function. This study aims to evaluate the effect of vildagliptin on endothelial function and arterial stiffness in patients with T2DM and hypertension.

METHODS

Fifty over 35-year-old patients with T2DM and hypertension, without cardiovascular disease, will be randomly allocated to two groups: group 1 will receive vildagliptin added-on to metformin and group 2, glibenclamide added-on to metformin. Biochemical tests (glycemia, glycated hemoglobin, total cholesterol, high-density lipoprotein cholesterol, triglycerides, creatinine, alanine aminotransferase, ultrasensitive C-reactive protein, and microalbuminuria), 24-h non-invasive ambulatory blood pressure monitoring, and assessment of endothelial function and arterial stiffness will be performed in both groups before and after 12 weeks of treatment. The endothelial function will be assessed by peripheral arterial tonometry, which measures the reactive hyperemia index (vasodilation), and arterial stiffness will be evaluated by applanation tonometry. All analysis will be performed using SPSS Statistical Software. For all analysis, a 2-sided P < 0.05 will be considered statistically significant.

RESULTS

The study started in December 2013 and patient recruitment is programed until October 2015. The expected results are that vildagliptin will improve the endothelial function in patients with T2DM and hypertension compared to glibenclamide treatment, independently of glycemic control.

CONCLUSIONS

It is expected that this DPP-4 inhibitor will improve endothelial function in patients with T2 DM.

TRIAL REGISTRATION

Clinical Trials NCT02145611, registered on 11 Jun 2013.

Relationship Between Short-Term Blood Pressure Variability and Subclinical Renal Damage in Essential Hypertensive Patients

The authors aimed to analyze the relationship between subclinical renal damage, defined as the presence of microalbuminuria or an estimated glomerular filtration rate (eGFR) between 30 mL/min/1.73 m(2) and 60 mL/min/1.73 m(2) and short-term blood pressure (BP) variability, assessed as average real variability (ARV), weighted standard deviation (SD) of 24-hour BP, and SD of daytime and nighttime BP. A total of 328 hypertensive patients underwent 24-hour ambulatory BP monitoring, 24-hour albumin excretion rate determination, and eGFR calculation using the Chronic Kidney Disease Epidemiology Collaboration equation. ARV of 24-hour systolic BP (SBP) was significantly higher in patients with subclinical renal damage (P=.001). This association held (P=.04) after adjustment for potential confounders. In patients with microalbuminuria, ARV of 24-hour SBP, weighted SD of 24-hour SBP, and SD of daytime SBP were also independently and inversely related to eGFR. These results seem to suggest that in essential hypertension, short-term BP variability is independently associated with early renal abnormalities.

Arterial stiffness, pulse pressure, and the kidney

Classical studies indicate that the contribution of kidneys to hypertension is almost exclusively related to the association between mean arterial pressure (MAP) and vascular resistance. Recent reports including estimates of glomerular filtration rate (GFR) have shown that pulse pressure (PP) and pulse wave velocity, 2 major indices of arterial stiffness, now emerge as significant predictors of cardiovascular risk and age-associated decline in GFR. Such findings are mainly observed in patients with hypertension and renal failure and in atherosclerotic subjects undergoing coronary angiography. In such patients, amplification of PP between ascending and terminal aorta at the renal site is constantly increased over 10mm Hg (P < 0.001), whereas MAP level remains continuously unmodified. This PP amplification is significantly associated with presence of proteinuria. Furthermore, increases in plasma creatinine and aortic stiffness are independently and positively correlated (P < 0.001) both in cross-sectional and longitudinal studies. All these relationships associating PP, arterial stiffness, and renal function are mainly observed in patients 60 years of age or older. Furthermore, in renal transplant patients and their donors, subjects have been recruited for evaluations of arterial stiffness and posttransplant decline in GFR. Determinants of GFR decline were evaluated 1 and 9 years after transplantation. The first year GFR decline was related to smoking and acute rejection, whereas the later was significantly and exclusively associated with donor age and aortic stiffness. Thus, in hypertensive humans, the observed association between PP and GFR suggests that the 2 parameters are substantially mediated by arterial stiffness, not exclusively by vascular resistance.

Low-grade albuminuria associated with brachial-ankle pulse wave velocity in young adults with type 2 diabetes mellitus in China

BACKGROUND

Cardiovascular disease is prevalent in type 2 diabetics, and microalbuminuria is associated with cardiovascular disease morbidity. We aimed to investigate the potential association between low-grade albuminuria and arterial stiffness in patients with type 2 diabetes.

METHODS

Between 2009 and 2013, a retrospective study was performed in 578 patients with type 2 diabetes (339 male patients and 239 female patients) with normal urinary albumin-to-creatinine ratios (ACRs; <30 mg/g) from Fuzhou, China. Patients were stratified into tertiles based on urinary ACR levels (lowest tertile, urinary ACR < 4.8 mg/g; highest tertile, urinary ACR ≥ 20.1 mg/g). Arterial stiffness was measured via brachial-ankle pulse wave velocity.

RESULTS

Brachial-ankle pulse wave velocity, age, duration of diabetes, systolic blood pressure and pulse wave velocity progressively increased across all urinary albumin-to-creatinine ratio tertiles (p < 0.05). Patients in the second and the highest tertiles had significantly elevated pulse wave velocity [114.6 mm/s (95% CI = 36.8-192.4) and 209.4 mm/s (95% CI = 131.8-286.9)], p = 0.004 and 0.000] compared with those in the lowest ACR tertile. The association between ACR and elevated pulse wave velocity still persisted in patients younger than 65 years of age and those with diabetes <10 years, conferring 45 or 51% greater risk of elevated pulse wave velocity (OR = 1.451; 95% CI = 1.119-1.881; p = 0.005 or OR = 1.515; 95% CI = 1.167-1.966; p = 0.0018) with each ACR tertile increment. Each ACR tertile increment conferred 31.7% higher risk of increased pulse wave velocity (OR = 1.317; 95% CI = 1.004-1.729; p = 0.0468).

CONCLUSIONS

Patients with type 2 diabetes with urinary albumin excretion in the upper normal range were still at risk for target organ damage. Low-grade albuminuria might be an early marker for the detection of arterial stiffness in patients with type 2 diabetes, especially in younger patients with type 2 diabetes with shorter durations of disease.

Target renal damage: the microvascular associations of increased aortic stiffness in patients with COPD

Background

Although renal impairment has been described in COPD, there is opportunity to evaluate further to determine nature and consider optimal management. Increased aortic stiffness, as seen in COPD, leads to reduced buffering of pulsatile flow. We hypothesised that urinary albumin creatinine ratio (UACR) would reflect glomerular damage related to aortic stiffness.

Methods

Patients with COPD and controls underwent spirometry, blood pressure, arterial stiffness - aortic pulse wave velocity (PWV) and provided a spot urine sample for UACR, with other renal biomarkers measured.

Results

The UACR was increased in patients (n = 52): 0.80 mg/mmol compared to controls (n = 34): 0.46 mg/mmol, p < 0.05. Aortic PWV was related to log₁₀ UACR in all subjects (r = 0.426, p < 0.001) and COPD patients alone. Aortic PWV was a significant variable for UACR with oxygen saturations, after accounting for potential confounders. Eight subjects (7 patients) reached a defined clinical microalbuminuria threshold, with aortic PWV greater in these patients compared to those patients without, although albuminuria is a continuum. Proximal tubular damage biomarkers, unlike the glomerular marker, were not different between patients and controls.

Conclusions

There is glomerular damage in patients with COPD evidenced by increased UACR, related to increased aortic stiffness. Besides the macrovascular prognostic implications of increased aortic stiffness, the microvascular state in COPD management should be considered.

Microalbuminuria is independently associated with arterial stiffness and vascular inflammation but not with carotid intima-media thickness in patients with newly diagnosed type 2 diabetes or essential hypertension

The association between microalbuminuria (MAU) and the indices of macrovascular complication in patients with newly diagnosed type 2 diabetes (D) or essential hypertension (H) was evaluated. Total 446 patients were classified into four groups according to the urinary albumin-to-creatinine ratio: MAU-D (n = 104), normoalbuminuria (NAU)-D (n = 114), MAU-H (n = 116), and NAU-H (n = 112). The indices of macrovascular complication including arterial stiffness evaluated by pulse-wave-velocity (PWV), carotid intima-media thickness (IMT), and vascular inflammation marked by high-sensitivity C-reactive protein (hsCRP) were assessed. PWV, IMT, and hsCRP were higher in patients with MAU than in those with NAU in both diabetes and hypertension groups. In both MAU-D and MAU-H groups, PWV and hsCRP levels were positively correlated with MAU level (MAU-D: r = 0.47, 0.41, MAU-H: r = 0.36, 0.62, respectively, P < 0.05). Additionally, PWV and hsCRP were independent factors predicting MAU (diabetes group: OR 1.85, 1.54, hypertension group: OR 1.38, 1.51, respectively, P < 0.001), but not IMT. MAU is independently associated with arterial stiffness and vascular inflammation but not with IMT in patients with newly diagnosed type 2 diabetes or essential hypertension, which emphasizes the importance of proactive clinical investigations for atherosclerotic complications in patients with MAU, even in newly diagnosed diabetes or hypertension.

Aortic pulse wave velocity is associated with measures of subclinical target organ damage

OBJECTIVES

Our goal was to evaluate the associations of central arterial stiffness, measured by aortic pulse wave velocity (aPWV), with subclinical target organ damage in the coronary, peripheral arterial, cerebral, and renal arterial beds.

BACKGROUND

Arterial stiffness is associated with adverse cardiovascular outcomes. We hypothesized that aPWV is associated with subclinical measures of atherosclerosis-coronary artery calcification (CAC) and ankle-brachial index (ABI) and arteriolosclerosis-brain white matter hyperintensity (WMH) and urine albumin-creatinine ratio (UACR).

METHODS

Participants (n = 812; mean age 58 years; 58% women, 71% hypertensive) belonged to hypertensive sibships and had no history of myocardial infarction or stroke. aPWV was measured by applanation tonometry, CAC by electron beam computed tomography, ABI using a standard protocol, WMH volume by brain magnetic resonance, and UACR by standard methods. WMH was log-transformed, whereas CAC and UACR were log-transformed after adding 1 to reduce skewness. The associations of aPWV with CAC, ABI, WMH, and UACR were assessed by multivariable linear regression using generalized estimating equations to account for the presence of sibships. Covariates included in the models were age, sex, body mass index, history of smoking, hypertension and diabetes, total and high-density lipoprotein cholesterol, estimated glomerular filtration rate, use of aspirin and statins, and pulse pressure.

RESULTS

The mean ± SD aPWV was 9.8 ± 2.8 m/s. After adjustment for age, sex, conventional cardiovascular risk factors, and pulse pressure, higher aPWV (1 m/s increase) was significantly associated with higher log (CAC + 1) (β ± SE = 0.14 ± 0.04; p = 0.0003), lower ABI (β ± SE = -0.005 ± 0.002; p = 0.02), and greater log (WMH) (β ± SE = 0.03 ± 0.009; p = 0.002), but not with log (UACR + 1) (p = 0.66).

CONCLUSIONS

Higher aPWV was independently associated with greater burden of subclinical disease in coronary, lower extremity, and cerebral arterial beds, highlighting target organ damage as a potential mechanism underlying the association of arterial stiffness with adverse cardiovascular outcomes.

Factors associated with brachial-ankle pulse wave velocity in the general population

The present study investigated factors that modify or affect arterial stiffness as assessed by brachial-ankle pulse wave velocity (baPWV) in the general population. Subjects had previously participated in a physical checkup program (n=911), and baPWV and urinary albumin and sodium excretion were also measured. Urine albumin was expressed as the ratio of urine albumin to urine creatinine. Individual salt intake was assessed by estimating 24-h urinary salt excretion and expressed as the ratio of estimated salt intake to body weight. The mean blood pressure and baPWV were 127.1±15.2/77.0±9.5 mm Hg and 15.9±3.3 m s(-1), respectively. Univariate analysis demonstrated that baPWV correlated with various factors including age, blood pressure, electrocardiogram voltage (SV(1)+RV(5)), urine albumin and salt intake. Multivariate regression analysis revealed that electrocardiogram voltage (P<0.001), systolic blood pressure (P<0.0001), urine albumin (P<0.001) and salt intake (P<0.001), independently correlated with baPWV after adjustment for other possible factors. Similar results were obtained for participants not taking any medication. These results suggest that the baPWV value is independently associated with individual salt intake and cardiac and renal damage, and could be a useful procedure for identifying individuals with concealed risk of cardiovascular disease.

The progressive pathway of microalbuminuria: from early marker of renal damage to strong cardiovascular risk predictor

There is clear evidence that urinary albumin excretion levels, even below the cut-off values currently used to diagnose microalbuminuria, are associated with an increased risk of cardiovascular events. The relationships of microalbuminuria with a variety of risk factors, such as hypertension, diabetes and metabolic syndrome and with several indices of subclinical organ damage, may contribute, at least in part, to explain the enhanced cardiovascular risk conferred by microalbuminuria. Nonetheless, several studies showed that the association between microalbuminuria and cardiovascular disease remains when all these risk factors are taken into account in multivariate analyses. Therefore, the exact pathophysiological mechanisms explaining the association between microalbuminuria and cardiovascular risk remain incompletely understood. The simple search for microalbuminuria in hypertensive patients may enable the clinician to better assess absolute cardiovascular risk, and its identification may induce physicians to encourage patients to make healthy lifestyle changes and perhaps would prompt to more aggressive modification of standard cardiovascular risk factors.

Arterial stiffness and dialysis calcium concentration

Arterial stiffness is the major determinant of isolated systolic hypertension and increased pulse pressure. Aortic stiffness is also associated with increased cardiovascular morbidity and mortality in patients with chronic kidney disease, hypertension, and general population. Hemodynamically, arterial stiffness results in earlier aortic pulse wave reflection leading to increased cardiac workload and decreased myocardial perfusion. Although the clinical consequence of aortic stiffness has been clearly established, its pathophysiology in various clinical conditions still remains poorly understood. The aim of the present paper is to review the studies that have looked at the impact of dialysis calcium concentration on arterial stiffness. Overall, the results of small short-term studies suggest that higher dialysis calcium is associated with a transient but significant increase in arterial stiffness. This calcium dependant increase in arterial stiffness is potentially explained by increased vascular smooth muscle tone of the conduit arteries and is not solely explained by changes in mean blood pressure. However, the optimal DCa remains to be determined, and long term studies are required to evaluate its impact on the progression of arterial stiffness.

Prehypertensive African-American women have preserved nitric oxide and renal function but high cardiovascular risk

AIMS

African-Americans, in particular women, exhibit disproportionate levels of hypertension, inflammation, and oxidative stress compared to other ethnic groups. The relationship between prehypertension, renal function, inflammation, and oxidative stress was examined.

METHODS

Twenty-eight African-American women (53.5 +/- 1.1 years) followed an AHA diet and then underwent 24-hour ambulatory BP (ABP) monitoring. Urinary albumin (uAlb), serum and urinary creatinine, glomerular filtration rate (GFR), 24-hour urinary Na(+) excretion, plasma superoxide dismutase, total antioxidant capacity (TAC), urinary (uNOx) and plasma (pNOx) nitric oxide levels, and high-sensitivity C-reactive protein (hsCRP) were measured.

RESULTS

When the group was divided by average 24-hour ABP into optimal and nonoptimal groups, a significant difference existed between the groups for uNOx (p = 0.001; nonoptimal: 933.5 +/- 140.4, optimal: 425.0 +/- 52.6 mumol/gCr), and for hsCRP (p = 0.018, nonoptimal: 3.9 +/- 0.7, optimal: 1.9 +/- 0.6 mg/l). Significant inverse relationships existed between hsCRP and uNOx and between uAlb and pNOx in the non-optimal group, between GFR and pNOx in the entire group, and positive association existed between TAC and uNOx in the optimal group.

CONCLUSIONS

These results suggest that in African-American women as BP levels rise toward hypertension, the NO/NOS balance may be associated with renal function, and may have implications for CV risk based on their hsCRP levels.