Interaction Between Renal Function and Microalbuminuria for Cardiovascular Risk in Hypertension

Night Shift Work, Genetic Risk, and Hypertension

OBJECTIVE

To perform a prospective cohort study to investigate whether night shift work is associated with incident hypertension and whether this association is modified by genetic susceptibility to hypertension because evidence on the association between night shift work and hypertension is insufficient.

METHODS

A total of 232,665 participants of UK Biobank who were recruited from 2006 to 2010 and observed to January 31, 2018, were included in this study. A Cox proportional hazards model with covariate adjustment was performed to assess the association between night shift work exposure and hypertension risk. We constructed a polygenic risk score (PRS) for genetic susceptibility to hypertension, which was used to explore whether genetic susceptibility to hypertension modified the effect of night shift work. The robustness of the results was assessed by sensitivity analysis.

RESULTS

Night shift workers had a higher hypertension risk than day shift workers, which increased with increasing frequency of night shift work (P_trend<.001). The association was attenuated but still remained statistically significant in the fully adjusted model. We explored the joint effect of night shift work and genetic susceptibility on hypertension. Permanent night shift workers with higher hypertension PRSs had higher risk of hypertension than day workers with low PRSs.

CONCLUSION

Night shift work exposure was associated with increased hypertension risk, which was modified by the genetic risk for hypertension, indicating that there is a joint effect of night shift work and genetic risk on hypertension.

Association of microalbuminuria and adverse outcomes in hypertensive patients: a meta-analysis

BACKGROUND

Studies on the association of microalbuminuria with adverse outcomes in patients with hypertension remain controversial. This meta-analysis aimed to assess the predictive value of microalbuminuria in hypertensive patients.

METHODS

PubMed and Embase databases were comprehensively searched for studies that published from their inceptions to July 10, 2020. Observational studies reporting the association of microalbuminuria (defined as urinary albumin excretion 30 and 300 mg/24 h urine or albumin/creatinine ratio 30-300 mg/g from a spot urine or equivalent value) with all-cause mortality or major adverse cardiovascular events (MACEs) in hypertensive patients were selected.

RESULTS

Nine studies with a total of 19,893 hypertensive patients were included. When compared with those without microalbuminuria, hypertensive patients with microalbuminuria had an increased risk of all-cause mortality (risk ratio [RR] 1.68; 95% confidence interval [CI] 1.46-1.93) and MACEs (RR 1.40; 95% CI 1.22-1.62), respectively. Gender-specific analysis indicated that microalbuminuria was significantly associated with an increased risk of all-cause mortality (RR 1.61; 95% CI 1.17-2.21) in men but not in women (RR 1.18; 95% CI 0.78-1.80).

CONCLUSION

This meta-analysis suggests that microalbuminuria is independently associated with higher risk of MACEs and all-cause mortality in hypertensive patients. Determination of microalbuminuria has potential to improve the risk classification of hypertension.

Vegetarian diet and blood pressure in a hospital-base study

Objective

Previous studies have reported that a vegetarian diet may lower blood pressure (BP), but the effect of diet on BP in asymptomatic participants with proteinuria is unknown. We examined the association of diet and BP in individuals with or without proteinuria.

Materials and Methods

This cross-sectional study analyzed data from participants who were more than 40 years old and received physical checkups at Taipei Tzu Chi Hospital from September 5, 2005, to December 31, 2016. Diets were assessed at baseline by a self-reported questionnaire and categorized as vegan, lacto-ovo vegetarian, or omnivore. There were 2818 (7.7%) vegans, 5616 (15.3%) lacto-ovo vegetarians, and 28,183 (77.0%) omnivores. The effect of different parameters on BP was determined using a multivariate multiple linear regression model with no intercept, with control for important characteristics and lifestyle confounders.

Results

The vegan group had a lower mean systolic BP (-3.87 mmHg, P < 0.001) and diastolic BP (-2.48 mmHg, P < 0.001) than the omnivore group. Participants with proteinuria had a higher systolic BP (4.26 mmHg, P < 0.001) and diastolic BP (2.15 mmHg, P < 0.001) than those without proteinuria. Interaction analysis indicated that vegan participants with proteinuria had a lower systolic BP (-2.73 mmHg, P = 0.046) and diastolic BP (-2.54 mmHg, P = 0.013) than other participants with proteinuria. However, individuals in the lacto-ovo group with proteinuria had a BP similar to other participants with proteinuria.

Conclusions

A vegan diet was associated with lower BP in asymptomatic participants with proteinuria. This diet could be a nonpharmacologic method to reduce BP.

Association between ELMO1 gene polymorphisms and diabetic nephropathy in an Iranian population

BACKGROUND

Diabetic nephropathy (DN) is one of the leading causes of death in patients with type 2 diabetes mellitus (T2DM). Several genome-wide association studies have introduced Engulfment and Cell Motility 1 (ELMO1) as a candidate gene which is associated with DN. This study assessed the association of ELMO1 gene polymorphisms with DN in order to investigate the effects of ELMO1 gene on susceptibility to DN in an Iranian population.

METHODS

In the present study, 100 patients with T2DM, 100 patients with DN and 100 healthy subjects who were matched for sex were selected. Allele and genotype frequencies were determined by Tetra-ARMS PCR technique. In all groups, levels of FBS, creatinine, urea, HbA1C, urine levels of albumin creatinine ratio and glomerular filtration rate were measured.

RESULTS

A statistically significant association was shown between G allele of rs741301 (odds ratio (OR) = 1.7 [95 % CI 1.17-2.63]; p value = 0.005), and GG genotypes of rs741301 (OR = 2.5 [95 % CI 1.2-5.4]; p value = 0.01) and DN. A significant association was not detected between allelic and genotypic frequencies of rs1345365 and DN. Linkage Disequilibrium (LD) between two variants was weak (D' = 0.11, r2 = 0.008). rs1345365A/rs741301A haplotypes were more frequent in patients with T2DM as compared to DN (OR = 0.5 [95 % CI 0.3-0.7]; p value = 0.0006). Also, genotypes of variant rs741301 in all subjects had significant difference with respect to the mean of ACR (p Value < 0.05).

CONCLUSION

This study first investigated the association of ELMO1 gene polymorphisms (rs741301) with DN in an Iranian population, supporting its key role as a candidate gene in the susceptibility to DN.

Renal and cardiovascular risk predictive value of two different microalbuminuria screening methods in patients with hypertension with/without diabetes in Portugal

MicRoAlbuminuria sCreening survEy (RACE) was a multicentre, observational, cross-sectional study conducted in primary health-care settings of Portugal. Here, we present a post-hoc analysis from the RACE study, assessing the renal and cardiovascular (CV) risk predictive value of two different microalbuminuria (MA) screening methods, nephelometry with 24-h urine (MA-24 h) and Micral test with occasional urine (MicralA) in patients with hypertension (HTN) with/without type 2 diabetes mellitus (T2DM). Out of 3065 patients, 1173 (38.3%) were in the HTN group without T2DM (HTN) and 1892 (61.7%) in the HTN group with T2DM (HTN+T2DM). The overall prevalence of MA was 50.6% determined by MicralA and 22.1% with MA-24 h. Urinary albumin excretion data obtained by both techniques correlated significantly (r_s=0.586; P<0.001). In all subjects, MicralA showed a sensitivity of 93%, specificity of 62% for detection of MA, with a positive predictive value of 41% and negative predictive value of 97%. With both methods, the presence of MA was independently associated with a higher risk (1.5- to 2.9-fold) of CV and renal organ damage in both HTN and HTN+T2DM groups. MicralA, due to its high sensitivity and negative predictive value, can be considered as a valid and reliable method for MA screening in patients with HTN with/without T2DM.

Biomarkers in cardiorenal syndrome

Cardiac and renal diseases often coexist. Treatment may prove difficult as early diagnosis and effective therapy may be hindered by a lack of robust markers of disease activity. However, several candidate molecules are now available which may help elucidate the complexities of organ cross-talk, enabling effective therapies. We discuss the available data on the commonly studied biomarkers of acute kidney injury with reference to the cardiorenal syndrome. Furthermore, we propose how the use of biomarkers as a panel may provide information which can guide therapy. Although this is a relatively new field, advances are rapid, and such options may well be available to the clinician soon.

Endothelial damage in long-term survivors of childhood cancer

PURPOSE

To evaluate the presence of vascular damage in long-term childhood cancer survivors (CCS) and sibling controls, and to evaluate the association between vascular damage parameters and cancer treatment and influence of cardiovascular risk factors.

PATIENTS AND METHODS

Vascular assessment was performed in 277 adult CCSs (median age at diagnosis, 9 years; range, 0 to 20 years; median current age, 28 years; range, 18 to 48 years) treated with potentially cardiovascular toxic anticancer treatment (ie, anthracyclines, platinum, and/or radiotherapy [RT]). Measurements included carotid- and femoral-wall intima-media thickness (IMT), flow-mediated vasodilatation of the brachial artery by ultrasound, assessment of endothelial and inflammatory marker proteins (including tissue-type plasminogen activator [t-PA], plasminogen activator inhibitor type 1 [PAI-I]), and cardiovascular risk factors. CCS assessments were compared with those of 130 sibling controls (median age, 26 years; range, 18 to 51 years).

RESULTS

At a median of 18 years (range, 5 to 31 years) after treatment, carotid and femoral IMTs in CCSs were not different from those of controls. However, CCSs who received RT as part of their treatment regimen had increased carotid and femoral IMTs and higher t-PA and PAI-I levels, indicating vascular damage and persistent endothelial activation. Patients treated with RT to the neck or chest also had greater femoral IMT. Greater IMT was associated with presence of cardiovascular risk factors (eg, hypertension and overweight).

CONCLUSION

After potentially cardiovascular toxic anticancer treatment, CCSs who received RT showed signs of endothelial damage and an unfavorable cardiovascular risk profile compared with controls. CCSs treated with localized RT had increased IMT outside the primary irradiation field. These abnormalities are probably involved in the pathogenesis of cardiovascular morbidity in CCSs.

Relationship between glomerular dysfunction and left-ventricular mass independent of haemodynamic factors in a community sample

AIM

To evaluate whether the relationship between early glomerular dysfunction and left-ventricular mass (LVM) occurs in a community sample and whether this relationship depends on haemodynamic factors.

METHODS

In 621 randomly selected participants from a community sample (332 were normotensive), estimated glomerular filtration rate (eGFR), LVM and dimensions were determined using echocardiography, and aortic blood pressure (BP) assessed from applanation tonometry and SphygmoCor software. Aortic pulse wave velocity (PWV) and high-quality 24-h BP values were available from 554 and 437 participants, respectively.

RESULTS

With adjustments for confounders (including clinic SBP), eGFR was associated with LVM index (LVMI) and LVM in excess of that predicted from stroke work (inappropriate LVM, LVMinappr) in all participants (LVMI: partial r = -0.18, P < 0.0001; LVMinappr: partial r = -0.17, P < 0.0001) and normotensive (LVMI: partial r = -0.23, P < 0.0001; LVMinappr: partial r = -0.22, P < 0.0001) separate from hypertensive patients. Marked differences in LVMinappr were noted in the eGFR range below 132 compared to at least 132 ml/min per 1.73 m (P < 0.0005). When replacing clinic BP with either aortic SBP, 24-h BP, PWV, stroke work (for LVMI), left-ventricular end-diastolic diameter (LVEDD), or circumferential wall stress in the regression models, eGFR retained strong associations with LVMI (P = 0.01 to <0.0001) and LVMinappr (P < 0.005 to <0.0001) and these effects were replicated in normotensive separate from hypertensive patients.

CONCLUSIONS

Strong relationships between eGFR and LVM occur at a community level irrespective of the presence of hypertension and independent of 24-h and aortic BP, PWV, LVEDD, stroke work and wall stress. Non-haemodynamic factors explain a considerable proportion of the relationship between early glomerular dysfunction and left-ventricular hypertrophy.

Sex differences in hypertension-related renal and cardiovascular diseases in Italy: the I-DEMAND study

AIM

The aim of this study is to evaluate the differences in the prevalence of chronic kidney disease (CKD) and of cardiovascular risk factors and diseases between men and women participating in the Italy Developing Education and awareness on MicroAlbuminuria in patients with hyperteNsive Disease (I-DEMAND) study.

METHODS

This is an observational, cross-sectional, multicenter study aimed at assessing prevalence and correlates of CKD among Italian hypertensive patients attending out-patient referral clinics. CKD was defined as glomerular filtration rate (GFR) less than 60 ml/min per 1.73 m(2) [Modification of Diet in Renal Disease (MDRD) study equation and Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) equation] and/or urine albumin-to-creatinine ratio of at least 2.5 mg/mmol in men and of at least 3.5 mg/mmol in women or both. Left-ventricular hypertrophy (LVH) was diagnosed by either ECG or echocardiography.

RESULTS

A total of 3558 study patients with renal data available were considered for this analysis: mean age was 61 ± 4 years and 37% had diabetes mellitus. Female patients (n = 1636, 46%) were older, with a greater prevalence of obesity and lower prevalence of smoking. The prevalence of concomitant coronary artery and peripheral artery diseases, but not of hypertension, diabetes mellitus, or heart failure, was lower in women than in men. The overall prevalence of albuminuria (21 vs. 32%; P = 0.001) and of microalbuminuria (16 vs. 23%; P = 0.001) was lower in women than in men. In women the prevalence of a reduced GFR estimated by both MDRD (33 vs. 21%; P = 0.001) and CKD-EPI equations (32 vs. 23%; P = 0.001) was higher than in men. CKD prevalence was similar in women and men (44 vs. 41%; P = 0.095 and 43 vs. 43%; P = 0.475, respectively, when MDRD and CKD-EPI eGFR estimations were used). The prevalence of LVH (diagnosed by either ECG or echocardiography) was similar in men and women (18 vs. 20%; P = 0.12).The main independent determinants of CKD were age, glycemia, uricemia, pulse pressure, hypertension duration, and previous cardiovascular diseases in men, and increasing age, glycemia, uricemia, pulse pressure, and a lower BMI in women.

CONCLUSION

Renal abnormalities are present in a significant number of female hypertensive patients attending hypertension clinics. Prevalence of reduced eGFR and of microalbuminuria, associated risk factors, and clinical conditions are different between men and women, suggesting the need to develop specific therapeutic strategies to prevent renal dysfunction and reduce associated morbidity and mortality.

Animal models of cardiorenal syndrome: a review

The incidence of heart failure and renal failure is increasing and is associated with poor prognosis. Moreover, these conditions do often coexist and this coexistence results in worsened outcome. Various mechanisms have been proposed as an explanation of this interrelation, including changes in hemodynamics, endothelial dysfunction, inflammation, activation of renin-angiotensin-aldosterone system, and/or sympathetic nervous system. However, the exact mechanisms initializing and maintaining this interaction are still unknown. In many experimental studies on cardiac or renal dysfunction, the function of the other organ was either not addressed or the authors failed to show any decline in its function despite histological changes. There are few studies in which the dysfunction of both heart and kidney function has been described. In this review, we discuss animal models of combined cardiorenal dysfunction. We show that translation of the results from animal studies is limited, and there is a need for new and better models of the cardiorenal interaction to improve our understanding of this syndrome. Finally, we propose several requirements that a new animal model should meet to serve as a tool for studies on the cardiorenal syndrome.

Pharmacokinetics of diltiazem hydrochloride delay-onset sustained-release pellet capsules in healthy volunteers

The pharmacokinetics (PK) of ordinary tablets and sustained release capsules of diltiazem hydrochloride in human clinical trials had been studied. The PK of diltiazem hydrochloride delay-onset sustained-release pellet capsules, a new dosage form, has not been reported, although it is very important to clinical use. In this paper, we investigated the PK of diltiazem hydrochloride delay-onset sustained-release pellet capsules and the food influence in Chinese healthy volunteers. The PK parameters indicated that the diltiazem hydrochloride delay-onset sustained-release pellet capsules appeared marked characteristics of delayed and controlled release. An opened-label, randomized and parallel clinical trial was conducted in 36 Chinese healthy volunteers with single oral dose (90 mg, 180 mg or 270 mg) and a multiple oral dose (90 mg d-1×6 d) administration. The effect of food on the PK of one single oral dose (360 mg) was investigated in 24 healthy Chinese volunteers. Plasma diltiazem concentration was determined by reversed-phase high-performance liquid chromatography (RP-HPLC) and the main pharmacokinetic parameters were analyzed by PKSolver (Ver 2.0). All clinical studies were conducted in the Clinical Pharmacological Center (No. JDX1999064) of Xiangya Hospital Affiliated Central South University, China. The PK parameters suggested that the new formulation had marked characteristics of delayed and controlled release of diltiazem, and food intake did not alter significantly diltiazem pharmacokinetic parameters.

Chronic kidney disease and measurement of albuminuria or proteinuria: a position statement

Optimal detection and subsequent risk stratification of people with chronic kidney disease (CKD) requires simultaneous consideration of both kidney function (glomerular filtration rate [GFR]) and kidney damage (as indicated by albuminuria or proteinuria). Measurement of urinary albuminuria and proteinuria is hindered by a lack of standardisation regarding requesting, sample collection, reporting and interpretation of tests. A multidisciplinary working group was convened with the goal of developing and promoting recommendations that achieve consensus on these issues. The working group recommended that the preferred method for assessment of albuminuria in both diabetic and non-diabetic patients is urinary albumin-to-creatinine ratio (UACR) measurement in a first-void spot urine specimen. Where a first-void specimen is not possible or practical, a random spot urine specimen for UACR is acceptable. The working group recommended that adults with one or more risk factors for CKD should be assessed using UACR and estimated GFR every 1-2 years, depending on their risk-factor profile. Recommended testing algorithms and sex-specific cut-points for microalbuminuria and macroalbuminuria are provided. The working group recommended that all pathology laboratories in Australia should implement the relevant recommendations as a vital component of an integrated national approach to detection of CKD.

Prognostic significance of a reduced glomerular filtration rate and interaction with microalbuminuria in resistant hypertension: a cohort study

OBJECTIVE

The prognostic importance of a reduced glomerular filtration rate (GFR) is unsettled in resistant hypertension. The aim was to evaluate GFR and its interaction with microalbuminuria as prognostic predictors in resistant hypertensive patients.

METHODS

In a prospective study, 531 resistant hypertensive patients had albuminuria measured and GFR estimated by Cockroft-Gault (eGFRCG) and Modification of Diet in Renal Disease (MDRD; eGFRMDRD) equations. Primary endpoints were a composite of fatal and nonfatal cardiovascular events, all-cause and cardiovascular mortality. Multiple Cox regression assessed the associations between reduced GFR and endpoints, and interaction with microalbuminuria.

RESULTS

After a median follow-up of 4.9 years, 72 patients died, 42 from cardiovascular causes; and 96 cardiovascular events occurred. Decreasing grades of eGFRMDRD were predictors of the composite endpoint with hazard ratios of 2.1 [95% confidence interval (CI) 1.1-3.8], 2.2 (1.2-3.9) and 3.5 (1.4-8.7) for the subgroups with eGFR between 60-89, 30-59 and less than 30 mg/min per 1.73 m, respectively. A decreased eGFRCG was predictive of the composite endpoint only in the lowest GFR subgroup (hazard ratio 2.7, 95% CI 1.0-7.1). The lowest eGFR subgroups were also associated with all-cause mortality, regardless of the estimated equation used. The presence of both reduced eGFR and microalbuminuria significantly increased cardiovascular risk in relation to one or another isolated, with hazard ratios of 3.0 (1.7-5.3), 2.9 (1.5-5.5) and 4.6 (2.2-10.0), respectively for the composite endpoint, all-cause and cardiovascular mortality.

CONCLUSION

A reduced GFR, mainly estimated by the MDRD equation, is an independent predictor of increased cardiovascular morbidity and mortality in resistant hypertension. The combination of a reduced GFR and increased albuminuria identifies patients with a very high cardiovascular risk.

Common variants in CNDP1 and CNDP2, and risk of nephropathy in type 2 diabetes

AIMS/HYPOTHESIS

Several genome-wide linkage studies have shown an association between diabetic nephropathy and a locus on chromosome 18q harbouring two carnosinase genes, CNDP1 and CNDP2. Carnosinase degrades carnosine (β-alanyl-L-histidine), which has been ascribed a renal protective effect as a scavenger of reactive oxygen species. We investigated the putative associations of genetic variants in CNDP1 and CNDP2 with diabetic nephropathy (defined either as micro- or macroalbuminuria) and estimated GFR in type 2 diabetic patients from Sweden.

METHODS

We genotyped nine single nucleotide polymorphisms (SNPs) and one trinucleotide repeat polymorphism (D18S880, five to seven leucine repeats) in CNDP1 and CNDP2 in a case-control set-up including 4,888 unrelated type 2 diabetic patients (with and without nephropathy) from Sweden (Scania Diabetes Registry).

RESULTS

Two SNPs, rs2346061 in CNDP1 and rs7577 in CNDP2, were associated with an increased risk of diabetic nephropathy (rs2346061 p = 5.07 × 10(-4); rs7577 p = 0.021). The latter was also associated with estimated GFR (β = -0.037, p = 0.014), particularly in women. A haplotype including these SNPs (C-C-G) was associated with a threefold increased risk of diabetic nephropathy (OR 2.98, 95% CI 2.43-3.67, p < 0.0001).

CONCLUSIONS/INTERPRETATION

These data suggest that common variants in CNDP1 and CNDP2 play a role in susceptibility to kidney disease in patients with type 2 diabetes.

Urinary proteins, N-acetyl-β-D-glucosaminidase activity and estimated glomerular filtration rate in hypertensive patients with normoalbuminuria and microalbuminuria

BACKGROUND

The aim of the study was to assess novel candidate markers measured in the urine of normoalbuminuric and microalbuminuric patients (the urinary albumin-to-creatinine ratio < 30 mg/mmol) with essential hypertension to be used for early detection and assessment of progressive deterioration in renal function.

METHODS

Albumin, α-1-antitrypsin, orosomucoid, transferrin, retinol-binding protein and α-1-microglobulin concentrations and the NAG (N-acetyl-β-D-glucosaminidase) activity in the urine were evaluated in 102 hypertensive subjects with urinary albumin-to-creatinine ratio (uACR) < 30 mg/mmol. The estimated glomerular filtration rate (e-GFR) was calculated using the Modification of Diet in Renal Disease Study equation.

RESULTS

The decreasing e-GFR values in normo- and microalbuminuric patients with essential hypertension were accompanied by significant increases (P < 0.05) in the NAG activity and uACR value in the urine. The e-GFR significantly (P < 0.05) correlated with the NAG activity in the urine, but no association was observed with the urinary concentrations of any of the individual proteins (P > 0.05).

CONCLUSIONS

In normoalbuminuric and microalbuminuric patients with essential hypertension renal impairment measured by e-GFR is related to the increased urinary NAG activity and uACR rather than elevated concentrations of individual proteins. Urinary NAG activity and uACR value seem independently promising candidate markers for use in assessing progression of early renal impairment in patients with hypertension.

Long-term effects of fosinopril and pravastatin on cardiovascular events in subjects with microalbuminuria:Ten years of follow-up of Prevention of Renal and Vascular End-stage Disease Intervention Trial (PREVEND IT)

BACKGROUND

The PREVEND IT investigated whether treatment targeted at lowering urinary albumin excretion (UAE) would reduce adverse cardiovascular events. We obtained extended follow-up data to approximately 10 years to investigate the long-term effects of fosinopril 20 mg and pravastatin 40 mg on cardiovascular outcomes in subjects with UAE >15 mg per 24 hours.

METHODS

The original PREVEND IT consisted of 864 participants and 839 survivors after 4 years. For every survivor, the primary end point determined by the combined incidence of cardiovascular mortality and hospitalization for cardiovascular morbidity was registered in several national databases and electronic hospital systems.

RESULTS

Mean total follow-up of the extended PREVEND IT was 9.5 years (range 9.4-10.7 years). Four years of treatment with fosinopril was not associated with a reduction in the primary end point compared with placebo (hazard ratio 0.87, 95% CI 0.61-1.24 [P = .42]) during long-term follow-up. After 9.5 years, subjects with a baseline UAE in the upper quintile (>50 mg/24 hours) had a total event rate of 29.5% and were at a higher risk for developing cardiovascular disease compared with less UAE (hazard ratio 2.03, 95% CI 1.38-2.97 [P ≤ .01]). In addition, 4 years of fosinopril treatment resulted in a risk reduction of 45% (95% CI 6%-75% [P = .04]) in this group compared with placebo. Subjects originally assigned to pravastatin had no overall risk reduction in the primary end point (P = .99).

CONCLUSIONS

Elevated UAE is associated with increased cardiovascular mortality and morbidity after 9.5 years of follow-up, with a doubling of the risk if the UAE is >50 mg per 24 hours. In this group, the benefits of 4-year treatment with fosinopril were sustained during posttrial follow-up for cardiovascular mortality and morbidity. We propose that UAE be used to estimate risk in the general population and that large clinical trials be designed to confirm the hypothesis that angiotensin-converting enzyme-inhibitor treatment may be beneficial in patients with mildly elevated UAE despite the absence of other comorbidities.

Effects of weight loss on renal function in overweight Japanese men

Obesity is known as an independent risk factor for renal injury. Sympathetic nerve activation may have an important role of the pathogenesis of obesity, and hypertension may underpin the development of cardiovascular events. In the present study, we evaluated the effects of weight loss (WL) on renal function, especially focusing on sympathetic nervous activity. In 154 overweight or obese Japanese men (89 normotensive and 65 untreated mild hypertensive subjects), body weight, body mass index (BMI), total body fat mass, blood pressure (BP), serum creatinine, blood urea nitrogen, creatinine clearance (CCr) (calculated with the Cockcroft-Gault equation) and plasma norepinephrine (NE) were measured before and after a 12-month period of WL with a mild caloric-restricted diet and exercise. A significant WL was defined as 10% or more WL compared with the entry period. In total, 97 (63.0%) subjects succeeded in significant (by 14.3%) WL at 12 months, and 57 subjects (37.0%) did not succeed in significant WL but they lost 7.7% weight. At entry, levels of plasma NE, serum creatinine and fat mass were significantly lower and CCr was greater in the group with a significant WL compared with those without WL. BMI, total body fat mass and plasma NE significantly decreased, and CCr increased with WL. At both baseline and at the 12-month period, fat mass and plasma NE negatively correlated with CCr and positively correlated with creatinine at each time point. Changes in fat mass and plasma NE over 12 months correlated with changes in creatinine, and only changes in fat mass negatively correlated with changes in CCr. Basal fat mass and plasma NE correlated positively with serum creatinine at 12 months and negatively with CCr at the same time point. In multiple regression analyses, basal plasma NE and fat mass were significant determinants of serum creatinine levels and CCr at 12 months. In conclusion, WL improved renal function (as evident from measures of creatinine and CCr) in overweight individuals. Basal plasma NE levels and total body fat mass could be predictors for improvement in renal function associated with WL. Suppression of sympathetic nervous activation associated with WL may have a role in the ameliorative effects on renal function.

Should targeting albuminuria be part of a cardiovascular risk reduction paradigm?

Cardiovascular disease (CVD) is the leading cause of morbidity and mortality in the United States as well as the rest of the world. Chronic kidney disease (CKD) is considered a CVD risk equivalent. The development of albuminuria has been identified as an additional possible risk marker that is almost unique to patients with CKD and a marker for predicting CVD risk. This review focuses on clinical and epidemiologic evidence regarding the role of albuminuria in the context of CVD development. It reviews the association of albuminuria with other comorbidities associated with increased cardiovascular risk and the modalities aimed at the reduction of albuminuria and maximizing of cardiovascular risk reduction.

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.

Role of oxidants/inflammation in declining renal function in chronic kidney disease and normal aging

Oxidant stress (OS) and inflammation increase in normal aging and in chronic kidney disease (CKD), as observed in human and animal studies. In cross-sectional studies of the US population, these changes are associated with a decrease in renal function, which is exhibited by a significant proportion of the population. However, since many normal adults have intact renal function, and longitudinal studies show that some persons maintain normal renal function with age, the link between OS, inflammation, and renal decline is not clear. In aging mice, greater oxidant intake is associated with increased age-related CKD and mortality, which suggests that interventions that reduce OS and inflammation may be beneficial for older individuals. Both OS and inflammation can be readily lowered in normal subjects and patients with CKD stage 3-4 by a simple dietary modification that lowers intake and results in reduced serum and tissue levels of advanced glycation end products. Diabetic patients, including those with microalbuminuria, have a decreased ability to metabolize and excrete oxidants prior to observable changes in serum creatinine. Thus, OS and inflammation may occur in the diabetic kidney at an early time. We review the evidence that oxidants in the diet directly lead to increased serum levels of OS and inflammatory mediators in normal aging and in CKD. We also discuss a simple dietary intervention that helps reduce OS and inflammation, an important and achievable therapeutic goal for patients with CKD and aging individuals with reduced renal function.

Clinical correlates of renal dysfunction in hypertensive patients without cardiovascular complications: the REDHY study

Our study was aimed to assess the clinical correlates of different degrees of renal dysfunction in a wide group of non-diabetic hypertensive patients, free from cardiovascular (CV) complications and known renal diseases, participating to the REDHY (REnal Dysfunction in HYpertension) study. A total of 1856 hypertensive subjects (mean age: 47+/-14 years), attending our hypertension centre, were evaluated. The glomerular filtration rate (GFR) was estimated by the simplified Modification of Diet in Renal Disease Study prediction equation. A 24-h urine sample was collected to determine albumin excretion rate (AER). Albuminuria was defined as an AER greater than 20 microg min(-1). We used the classification proposed by the US National Kidney Foundation's guidelines for chronic kidney disease (CKD) to define the stages of renal function impairment. In multiple logistic regression analysis, the probability of having stage 1 and stage 2 CKD was significantly higher in subjects with greater values of systolic blood pressure (SBP) and with larger waist circumference. SBP was also positively related to stage 3 CKD. Stage 3 and stages 4-5 CKD were inversely associated with waist circumference and directly associated with serum uric acid. Age was inversely related to stage 1 CKD and directly related to stage 3 CKD. The factors associated with milder forms of kidney dysfunction are, in part, different from those associated with more advanced stages of renal function impairment.

Renal and cardiac abnormalities in primary hypertension

OBJECTIVE

The relationship between mild reduction in renal function and cardiac structure and function have not yet been fully elucidated. We investigated cardiac and renal abnormalities in 400 untreated, nondiabetic patients (65% men, mean age 47 years) with primary hypertension and normal serum creatinine.

METHODS

Renal abnormalities were defined as creatinine clearance less than 75 ml/min per 1.73 m2 (Cockcroft-Gault formula) and/or the presence of microalbuminuria (albumin-to-creatinine ratio). Left ventricular structure and function were assessed by echocardiography.

RESULTS

The prevalence of microalbuminuria and reduced creatinine clearance was 13 and 31%, respectively. Patients with renal abnormalities shared greater left ventricular mass index, higher prevalence of left ventricular hypertrophy, and unfavorable geometric patterns. Microalbuminuria was also associated with inappropriate left ventricular mass and depressed midwall fractional shortening, whereas reduced creatinine clearance was associated with lower stroke volume and higher central pulse pressure/stroke volume ratio and total peripheral resistance. Stepwise regression analysis showed that both albuminuria and creatinine clearance were independently related to left ventricular mass. Logistic regression analysis of the reciprocal interaction of microalbuminuria and reduced creatinine clearance on the occurrence of subclinical cardiac damage showed that reduced creatinine clearance entailed a greater risk of left ventricular hypertrophy in patients with normal albuminuria alone, whereas the presence of microalbuminuria was associated with a greater risk of left ventricular hypertrophy independently of creatinine clearance.

CONCLUSIONS

These findings provide further proof of the role of cardiorenal interaction in the development of hypertension-related cardiovascular disease, and may have clinical implications.

How should proteinuria be detected and measured?

Proteinuria is a classic sign of kidney disease and its presence carries powerful prognostic information. Although proteinuria testing is enshrined in clinical practice guidelines, there is surprising variation among such guidelines as to the definition of clinically significant proteinuria. There is also poor agreement as to whether proteinuria should be defined in terms of albumin or total protein loss, with a different approach being used to stratify diabetic and non-diabetic nephropathy. Further, the role of reagent strip devices in the detection and assessment of proteinuria is unclear. This review explores these issues in relation to recent national and international guidelines on chronic kidney disease (CKD) and epidemiological evidence linking proteinuria and clinical outcome. The authors argue that use of urinary albumin measurement as the front-line test for proteinuria detection offers the best chance of improving the sensitivity, quality and consistency of approach to the early detection and management of CKD.

Losartan chemistry and its effects via AT1 mechanisms in the kidney

Besides the importance of the renin-angiotensin system (RAS) in the circulation and other organs, the local RAS in the kidney has attracted a great attention in research in last decades. The renal RAS plays an important role in the body fluid homeostasis and long-term cardiovascular regulation. All major components and key enzymes for the establishment of a local RAS as well as two important angiotensin II (Ang II) receptor subtypes, AT1 and AT2 receptors, have been confirmed in the kidney. In additional to renal contribution to the systemic RAS, the intrarenal RAS plays a critical role in the regulation of renal function as well as in the development of kidney disease. Notably, kidney AT1 receptors locating at different cells and compartments inside the kidney are important for normal renal physiological functions and abnormal pathophysiological processes. This mini-review focuses on: 1) the local renal RAS and its receptors, particularly the AT1 receptor and its mechanisms in physiological and pathophysiological processes; and 2) the chemistry of the selective AT1 receptor blocker, losartan, and the potential mechanisms for its actions in the renal RAS-mediated disease.