Serum aldosterone and death, end-stage renal disease, and cardiovascular events in blacks and whites: findings from the Chronic Renal Insufficiency Cohort (CRIC) Study

Adverse Effects of Aldosterone: Beyond Blood Pressure

Aldosterone is a steroid hormone that primarily acts through activation of the mineralocorticoid receptor (MR), a nuclear receptor responsible for downstream genomic regulation. Classically, activation of the MR in the renal tubular epithelium is responsible for sodium retention and volume expansion, raising systemic blood pressure. However, activation of the MR across a wide distribution of tissue types has been implicated in multiple adverse consequences for cardiovascular, cerebrovascular, renal, and metabolic disease, independent of blood pressure alone. Primary aldosteronism, heart failure, and chronic kidney disease are states of excessive aldosterone production and MR activity where targeting MR activation has had clinical benefits out of proportion to blood pressure lowering. The growing list of established and emerging therapies that target aldosterone and MR activation may provide new opportunities to improve clinical outcomes and enhance cardiovascular and renal health.

Association of the trajectory of plasma aldosterone concentration with the risk of cardiovascular disease in patients with hypertension: a cohort study

The purpose of this study was to determine the long-term pattern of plasma aldosterone concentration (PAC) trajectories and to explore the relationship between PAC trajectory patterns and cardiovascular disease (CVD) risk in patients with hypertension. Participants were surveyed three times between 2010 and 2016, and latent mixed modeling was employed to determine the trajectory of PAC over the exposure period (2010-2016). A Cox regression analysis was used to examine the association between PAC trajectory patterns and the risk of CVD (stroke and myocardial infarction). Hazard ratios (HRs) with corresponding 95% confidence intervals (CIs) were calculated and reported. During a median follow-up of 4.10 (3.37-4.50) years, 82 incident CVD cases (33 myocardial infarction cases and 49 stroke cases) were identified. Among all three PAC models, the high-stability PAC pattern exhibited the highest risk of CVD. After full adjustment for all covariables, HRs were 2.19 (95% CI 1.59-3.01) for the moderate-stable pattern and 2.56 (95% CI 1.68-3.91) for the high-stable pattern in comparison to the low-stable pattern. Subgroup and sensitivity analyses verified this association. The presence of a high-stable PAC trajectory pattern is associated with an elevated risk of CVD in hypertensive patients. Nevertheless, more studies are warranted to confirm these findings.

Primary Aldosteronism in Chronic Kidney Disease: Blood Pressure Control and Kidney and Cardiovascular Outcomes After Surgical Versus Medical Management

BACKGROUND

Diagnosis and treatment of primary aldosteronism (PA) in chronic kidney disease (CKD) may be deferred due to limited evidence supporting safety and efficacy of treatment. Our goal was to assess clinical outcomes in patients with PA and CKD who received surgical or medical management.

METHODS

We conducted a multicenter, retrospective cohort study of patients with PA and CKD who underwent adrenal vein sampling from 2009-2019. We characterized clinical outcomes and evaluated differences by surgical versus medical management. Primary outcomes were systolic blood pressure and number of antihypertensive medications. Secondary outcomes were diastolic blood pressure, serum potassium, estimated glomerular filtration rate (eGFR), and kidney and cardiovascular events. Analyses were adjusted for age, sex, race, cardiovascular disease, diabetes, and eGFR.

RESULTS

Of 239 participants with PA and CKD, 158 (66%) underwent adrenalectomy, and 81 (34%) were treated medically. Mean age was 57±10 years, 67% were female, mean eGFR was 45±12 mL/min per 1.73 m2, and 49% were on potassium supplementation. At 5 years, mean blood pressure decreased from 149±22/85±14 to 131±28/78±16 mm Hg and mean number of antihypertensive medications decreased from 4.0±1.5 to 2.4±1.4. Adrenalectomy, compared to medical management, was associated with similar systolic blood pressure (-0.90 mm Hg [95% CI, -6.99 to 5.07]) but fewer medications (1.7 [95% CI, -2.24 to -1.10]), and no difference in potassium levels or kidney or cardiovascular outcomes.

CONCLUSIONS

Patients with PA and CKD are likely to benefit from either surgical adrenalectomy or medical management. Detection and treatment of PA may help to reduce blood pressure and medication burden in patients with CKD.

Proteomic cardiovascular risk assessment in chronic kidney disease

AIMS

Chronic kidney disease (CKD) is widely prevalent and independently increases cardiovascular risk. Cardiovascular risk prediction tools derived in the general population perform poorly in CKD. Through large-scale proteomics discovery, this study aimed to create more accurate cardiovascular risk models.

METHODS AND RESULTS

Elastic net regression was used to derive a proteomic risk model for incident cardiovascular risk in 2182 participants from the Chronic Renal Insufficiency Cohort. The model was then validated in 485 participants from the Atherosclerosis Risk in Communities cohort. All participants had CKD and no history of cardiovascular disease at study baseline when ∼5000 proteins were measured. The proteomic risk model, which consisted of 32 proteins, was superior to both the 2013 ACC/AHA Pooled Cohort Equation and a modified Pooled Cohort Equation that included estimated glomerular filtrate rate. The Chronic Renal Insufficiency Cohort internal validation set demonstrated annualized receiver operating characteristic area under the curve values from 1 to 10 years ranging between 0.84 and 0.89 for the protein and 0.70 and 0.73 for the clinical models. Similar findings were observed in the Atherosclerosis Risk in Communities validation cohort. For nearly half of the individual proteins independently associated with cardiovascular risk, Mendelian randomization suggested a causal link to cardiovascular events or risk factors. Pathway analyses revealed enrichment of proteins involved in immunologic function, vascular and neuronal development, and hepatic fibrosis.

CONCLUSION

In two sizeable populations with CKD, a proteomic risk model for incident cardiovascular disease surpassed clinical risk models recommended in clinical practice, even after including estimated glomerular filtration rate. New biological insights may prioritize the development of therapeutic strategies for cardiovascular risk reduction in the CKD population.

Association of Aldosterone with Mortality in the General Population

INTRODUCTION

Aldosterone excess is linked to cardiovascular events and mortality as well as to low-grade inflammation in the context of metabolic diseases. Whether mildly elevated aldosterone levels in the general population promote cardiovascular risk is still under debate. We analyzed the association of plasma aldosterone concentrations with incident cardiovascular events, cardiovascular and all-cause mortality as well as with biomarkers of subclinical inflammation in the population-based KORA F4 study.

METHODS

Plasma aldosterone concentrations were measured with an in-house immunoflurometric assay. The analyses included 2935 participants (n=1076 for selected biomarkers of subclinical inflammation) with a median follow-up of 8.7 (8.2; 9.1) years. The associations were estimated using Cox proportional hazard and linear regression models adjusted for renin, sex, age, body mass index, arterial hypertension, diabetes, estimated glomerular filtration rate, low- and high-density lipoprotein cholesterol, physical activity, smoking, use of angiotensin-converting enzyme inhibitors, angiotensin receptor blockers, beta-blockers, diuretics and calcium channel blockers.

RESULTS

Aldosterone was significantly associated with all-cause mortality (hazard ratio per standard deviation increase: 1.20; 95% confidence interval 1.04-1.37), but not with cardiovascular mortality, incident cardiovascular events, or with biomarkers of subclinical inflammation.

CONCLUSIONS

Aldosterone was associated with all-cause mortality in the population-based KORA F4 study, but the previously described associations of excess aldosterone with cardiovascular complications and biomarkers of subclinical inflammation could not be shown.

Primary Aldosteronism and the Role of Mineralocorticoid Receptor Antagonists for the Heart and Kidneys

Primary aldosteronism (PA) is the most common cause of secondary hypertension but is frequently underrecognized and undertreated. Patients with PA are at a markedly increased risk for target organ damage to the heart and kidneys. While patients with unilateral PA can be treated surgically, many patients with PA are not eligible or willing to undergo surgery. Steroidal mineralocorticoid receptor antagonists (MRAs) are highly effective for treating PA and reducing the risk of target organ damage. However, steroidal MRAs are often underprescribed and can be poorly tolerated by some patients due to side effects. Nonsteroidal MRAs reduce adverse renal and cardiovascular outcomes among patients with diabetic kidney disease and are bettertolerated than steroidal MRAs. While their blood pressure-lowering effects remain unclear, these agents may have a potential role in reducing target organ damage in patients with PA.

Modulation of cardiometabolic risk and CardioRenal syndrome by oral vitamin D3 supplementation in Black and White Southern Sahara residents with chronic kidney disease Stage 3: focus on racial and ethnic disparities

OBJECTIVES

Several studies have shown that cholecalciferol supplementation (25OHD-S) in chronic kidney disease (CKD) improves kidney injury by reducing fibrosis-related vascular calcification and declining apoptosis-linked nephron damage.

METHODS

The oral 25OHD-S was evaluated in 60,000 IU/month/36 weeks versus in 2000 IU/d/24 weeks in CKD Stage 3 with serum 25OHD level < 20 ng/mL. The study was undertaken on 156 black subjects and 150 white subjects Southern Sahara (SS). All biomarkers of cardiometabolic (CMet) and cardiorenal (CRenal) syndrome, Renin-angiotensin-aldosterone system (RAAS) profile, secondary hyperparathyroidism (SHPT), N-terminal pro B-type natriuretic peptide (NT-proBNP), Troponin T (cTnT) and atherogenicity risk were assessed by biochemical methods. Estimate glomerular filtration rate (eGFR) by chronic CKD-EPI equation formula. Total serum vitamin D by liquid chromatography-tandem mass spectrometry (MS).

RESULTS

Vitamin D deficiency alters in the same manner CMet, CRenal, and others biomarkers in both groups SS; however, these disorders are more acute in blacks compared to whites SS. Oral 25OHD-S a highlighted improvement of eGFR drop, SHPT decrease, decline proteinuria, and cardiac failure risk (NT-proBNP and cTnT) attenuation. Concomitantly, 25OHD-S normalizes Renin, Aldosterone, and Angiotensin System (RAAS) activity. Nevertheless, homocysteine and Lp (a) do not modulate by 25OHD-S.

CONCLUSIONS

The oral vitamin D3 supplementation, according the dose, and the treatment duration does not like in black-skinned people versus to white-skinned inhabitants, while the 02 groups are native to the same Saharan environment. It emerge that a high intermittent dose through an extensive supplementation (60,000 IU/36 weeks) was more effective in black subjects. At opposite, a lower dose during a short period supplementation is sufficient (2000 IU/24 weeks) in white subjects.

Aldosterone in chronic kidney disease and renal outcomes

AIMS

Randomized controlled trials have demonstrated the efficacy of mineralocorticoid receptor (MR) antagonism in delaying chronic kidney disease (CKD) progression in diabetes; however, they have not investigated the role of aldosterone or whether these beneficial effects could be achieved in individuals without diabetes.

METHODS AND RESULTS

The association between serum aldosterone concentrations and kidney disease progression was investigated among 3680 participants in the Chronic Renal Insufficiency Cohort. The primary outcome was CKD progression [defined as the composite of 50% decline in estimated glomerular filtration rate (eGFR) or end-stage kidney disease, whichever occurred first]. The associations between serum aldosterone and kidney disease outcomes were assessed using Cox proportional hazard models. At baseline, higher aldosterone concentrations were associated with a lower eGFR, lower serum potassium, greater urinary potassium, and protein excretion. Over a median follow-up of 9.6 years, 1412 participants developed CKD progression. In adjusted models, each doubling of serum aldosterone was associated with a 11% increased risk of CKD progression [hazard ratio (HR) 1.11, 95% confidence interval (CI) 1.04-1.18]. Individuals with the highest quartile of serum aldosterone had a 45% increased risk of CKD progression (HR 1.45, 95% CI 1.22-1.73) compared with the lowest quartile. The risk for CKD progression was similar regardless of whether patients had concomitant diabetes (P-interaction = 0.10).

CONCLUSION

Higher serum aldosterone levels among individuals with CKD are independently associated with an increased risk for kidney disease progression, irrespective of concomitant diabetes. These findings provide mechanistic support for MR antagonists in delaying CKD progression and suggest that they may also have a role in those without diabetes.

Oral Cholecalciferol Supplementation in Sahara Black People with Chronic Kidney Disease Modulates Cytokine Storm, Oxidative Stress Damage and Athero-Thromboembolic Risk

The 25-hydroxyvitamin D3 (25OHD3) deficiency in chronic kidney disease (CKD) is associated with immune system dysfunction (pro-inflammatory cytokines storm) through macrophages renal infiltration, oxidative stress (OxS) damage and athero-thromboembolic risk. Conversely, cholecalciferol supplementation (25OHD-S) prevents kidney fibrosis by inhibition of vascular calcification and nephrotic apoptosis (nephrons reduction). The objective of this study was to investigate the pleiotropic effects of 25OHD-S on immunomodulation, antioxidant status and in protecting against thromboembolic events in deficiency CKD Black and White individuals living in the Southern Sahara (SS). The oral 25OHD-S was evaluated in 60,000 IU/month/36 weeks versus in 2000 IU/day/24 weeks in Black (n = 156) and White (n = 150). Total serum vitamin D was determined by liquid chromatography-tandem mass spectrometry. All biomarkers of pro-inflammatory cytokines (PIC) were assessed by ELISA tests. OxS markers were assessed by Randox kits. Homocysteine and lipoproteine (a) were evaluated by biochemical methods as biomarkers of atherothromboembolic risk. All statistical analyses were performed with Student’s t-test and one-way ANOVA. The Pearson test was used to calculate the correlation coefficient. The means will be significantly different at a level of p value < 0.05. Multiple logistic regressions were performed using Epi-info and Statview software. Vitamin D deficiency alters the PIC profile, OxS damage and atherothrombogenic biomarkers in both SS groups in the same manner; however, these disorders are more acute in Black compared to White SS individuals. The results showed that the serum 25OHD3 concentrations became normal (>75 nmol/L or >30 ng/mL) in the two groups. We have shown that the dose and duration of 25OHD-S treatment are not similar in Black SS residents compared to White SS subjects, whilst the same inhabit the south Sahara environment. It appears that a high dose intermittent over a long period (D60: 36 weeks) was more efficient in Black people; while a lower dose for a short time is sufficient (D2: 24 weeks) in their White counterparts. The oral 25OHD-S attenuates PIC overproduction and OxS damage, but does not reduce athero-thromboembolic risk, particularly in Black SS residents.

Effect of spironolactone on vascular stiffness in hemodialysis patients: a randomized crossover trial

Background

The role of spironolactone treatment in hemodialysis patients is debated, but a survival benefit is suggested. Mineralocorticoids and chronic kidney disease have been linked to cardiovascular fibrosis. Therefore, we hypothesized that spironolactone would affect vascular stiffness, cardiac systolic, and diastolic function in hemodialysis patients.

Methods

This was a randomized crossover study in hemodialysis patients supplemented with an echocardiographic case series. All outcomes reported here were secondary in the trial and were assessed without blinding. Block randomization and allocation determined treatment order. Participants received 50 mg spironolactone daily for 12 weeks and untreated observation for another 12 weeks. Pulse wave velocity (PWV) was measured before and after treatment and observation. Doppler-echocardiography was conducted before and after treatment. Systemic arterial compliance indexed to body surface area (SACi), left ventricular ejection fraction (LVEF), the peak early diastolic mitral inflow velocity (E), the peak late diastolic mitral inflow velocity (A), and the peak early diastolic myocardial lengthening velocity (E') were measured. E/A and E/E' were then calculated. Statistical analyses were conducted per protocol. A generalized linear mixed model with random participant effects was used for PWV. The Wilcoxon signed-rank test was used for echocardiographic variables.

Results

Thirty participants were recruited, 18 completed follow-up, and 17 were included in PWV-analyses. Spironolactone treatment showed a tendency toward an increase in PWV of 1.34 (95% confidence interval: -0.11 to 2.78) m/s, which was not statistically significant (P = 0.07). There were no significant changes in any of the other variables (LVEF, E/A, E/E', or SACi).

Conclusions

We found no evidence supporting an effect of 12-week administration of spironolactone 50 mg daily on vascular stiffness, cardiac systolic, or diastolic function in hemodialysis patients.

Heightened Cardiovascular Risk in Hypertension Associated With Renin-Independent Aldosteronism Versus Renin-Dependent Aldosteronism: A Collaborative Study

Background While both renin-dependent and renin-independent aldosterone secretion contribute to aldosteronism, their relative associations with cardiovascular disease (CVD) risk has not been investigated. Methods and Results A total of 2909 participants from the FOS (Framingham Offspring Study) with baseline, serum aldosterone concentration, and plasma renin concentration who attended the sixth examination cycle and were followed up until 2014 and who were free of CVD were included. We further recruited 2612 hypertensive participants from the CONPASS (Chongqing Primary Aldosteronism Study). Captopril challenge test was performed to confirm renin-dependent or -independent aldosteronism in CONPASS. Among 1433 hypertensive subjects of FOS, when compared with those with serum aldosterone concentration <10 ng dL^-1 (normal aldosterone), participants who had serum aldosterone concentration ≥10 ng dL^-1 and plasma renin concentration ≤15 mIU L^-1 (identified as renin-independent aldosteronism) showed a higher risk of CVD (hazard ratio, 1.40 [95% CI, 1.08-1.82]), while those who had serum aldosterone concentration ≥10 ng dL^-1 and plasma renin concentration >15 mIU L^-1 (identified as renin-dependent aldosteronism) showed an unchanged CVD risk. In CONPASS, renin-independent aldosteronism carried a significantly higher risk of CVD than normal aldosterone (odds ratio, 2.57 [95% CI, 1.13-5.86]), while the CVD risk remained unchanged in renin-dependent aldosteronism. Elevation of the urinary potassium-to-sodium excretion ratio, reflective of mineralocorticoid receptor activity, was only observed in participants with renin-independent aldosteronism. Conclusions Among patients with hypertension, renin-independent aldosteronism is more closely associated with CVD risk than renin-dependent aldosteronism.

Metabolic Acidosis and Cardiovascular Disease in CKD

Rationale & Objective

Metabolic acidosis related to chronic kidney disease (CKD) is associated with an accelerated decline in glomerular filtration rate (GFR) and the development of end-stage kidney disease. Whether metabolic acidosis is associated with cardiovascular (CV) events in patients with CKD is unclear.

Study Design

Retrospective cohort study.

Setting & Participants

The Optum De-identified Electronic Health Records Dataset, 2007–2017, was used to generate a cohort of patients with non-dialysis-dependent CKD who had at least 3 estimated GFR < 60 mL/min/1.73 m². Patients with metabolic acidosis (serum bicarbonate 12 to <22 mEq/L) or normal serum bicarbonate (22‒29 mEq/L) at baseline were identified by 2 consecutive measurements 28‒365 days apart.

Predictor

Serum bicarbonate as a continuous variable.

Outcome

Primary outcome was a composite of major adverse cardiovascular events (MACE+). Secondary outcomes included individual components of the composite outcome.

Analytical Approach

Cox proportional hazards models to evaluate the association between 1-mEq/L increments in serum bicarbonate and MACE+.

Results

A total of 51,558 patients were evaluated, 34% had metabolic acidosis. The median follow-up period was 3.9–4.5 years, depending on the outcome assessed. The adjusted hazard ratio (HR) for MACE+ was 0.964 (95% CI, 0.961–0.968). For the individual components of incident heart failure (HF), stroke, myocardial infarction (MI), and CV death, HRs were 0.98 (95% CI, 0.97–0.98), 0.98 (95% CI, 0.97–0.99), 0.96 (95% CI, 0.96–0.97), and 0.94 (95% CI, 0.93–0.94), respectively, for every 1-mEq/L increase in serum bicarbonate.

Limitations

Possible residual confounding.

Conclusions

Metabolic acidosis in CKD is associated with an increased risk of MACE+ as well as the individual components of incident HF, stroke, MI, and CV death. Randomized controlled trials evaluating treatments for the correction of metabolic acidosis in CKD to prevent CV events are needed.

Longitudinal Changes in Prorenin and Renin in the Chronic Renal Insufficiency Cohort

INTRODUCTION

Prorenin, a precursor of renin, and renin play an important role in regulation of the renin-angiotensin system. More recently, receptor-bound prorenin has been shown to activate intracellular signaling pathways that mediate fibrosis, independent of angiotensin II. Prorenin and renin may thus be of physiologic significance in CKD, but their plasma concentrations have not been well characterized in CKD.

METHODS

We evaluated distribution and longitudinal changes of prorenin and renin concentrations in the plasma samples collected at follow-up years 1, 2, 3, and 5 of the Chronic Renal Insufficiency Cohort (CRIC) study, an ongoing longitudinal observational study of 3,939 adults with CKD. Descriptive statistics and multivariable regression of log-transformed values were used to describe cross-sectional and longitudinal variation and associations with participant characteristics.

RESULTS

A total of 3,361 CRIC participants had plasma available for analysis at year 1. The mean age (±standard deviation, SD) was 59 ± 11 years, and the mean estimated glomerular filtration rate (eGFR, ± SD) was 43 ± 17 mL/min per 1.73 m2. Median (interquartile range) values of plasma prorenin and renin at study entry were 4.4 (2.1, 8.8) ng/mL and 2.0 (0.8, 5.9) ng/dL, respectively. Prorenin and renin were positively correlated (Spearman correlation 0.51, p < 0.001) with each other. Women and non-Hispanic blacks had lower prorenin and renin values at year 1. Diabetes, lower eGFR, and use of angiotensin-converting enzyme inhibitors, angiotensin receptor blockers, statins, and diuretics were associated with higher levels. Prorenin and renin decreased by a mean of 2 and 5% per year, respectively. Non-Hispanic black race and eGFR <30 mL/min/1.73 m2 at year 1 predicted a steeper decrease in prorenin and renin over time. In addition, each increase in urinary sodium excretion by 2 SDs at year 1 increased prorenin and renin levels by 4 and 5% per year, respectively.

DISCUSSION/CONCLUSIONS

The cross-sectional clinical factors associated with prorenin and renin values were similar. Overall, both plasma prorenin and renin concentrations decreased over the years, particularly in those with severe CKD at study entry.

Superiority of albumin-globulin ratio over albumin to predict mortality in patients undergoing peritoneal dialysis

There is increasing evidence showing that albumin–globulin ratio (AGR) can predict the survival of patients in many types of malignancies. However, no study was done to explore the value of AGR in peritoneal dialysis (PD) patients. A total of 554 incident patients undergoing PD from January 2001 through July 2016 were enrolled for this retrospective observational study. The outcomes of interest were all-cause mortality and cardiovascular disease (CVD) mortality. Baseline patient’s socio-demographic data, pharmacotherapy, comorbidities, laboratory and PD-related parameters were collected and used in the multivariate Cox models. The predictive value of AGR on mortality risk was compared with other markers using area under the receiver operating characteristic curve (AUC) analysis. Among the study participants, there were 265 (47.83%) men and the mean follow-up time was 3.87 ± 3.15 years. Univariate Cox analysis showed that low AGR was significantly associated with worse outcomes in terms of all-cause and CVD mortality and it remained an independent predictor in the multivariate models. The fully adjusted hazard ratios for the low AGR group versus high AGR group were 2.12 (95% CI 1.34–3.35, p = 0.001) and 2.58 (95% CI 1.42–4.7, p = 0.002) for all-cause and CVD mortality, respectively. The predictive ability of AGR for mortality risk was superior to that of other biomarkers based on AUC calculations. In conclusion, low AGR was independently associated with higher all-cause and CVD mortality risks in patients undergoing PD.

Aldosterone renin ratio and chronic kidney disease

As a component of the metabolic syndrome, hypertension (HTN) is increasing throughout the world with variable percentages, but mostly among developing world. Aldosterone plays a role in the relationship between aldosterone and nephropathy. We aimed to evaluate the relationship between aldosterone renin ratio (ARR) and chronic kidney disease (CKD). Variables drawn from the computerized hospital information database were all patients who had an ARR above 35 (if aldosterone reading was above 300 pmol/L). A total of 1584 patients, of whom 777 were male and 807 were female, with a mean [standard deviation (SD)] of 43.3 (16.5) years were studied. The mean ARR was 210.1 (SD: 246.4) in males and 214.3 and 210.1 in females, P = 0.51. The mean estimated glomerular filtration rate (eGFR) was 50.2 (SD 12.6); in males, it was 49.99 (0.90) and in females, it was 50.48 (0.92), P = 0.70. The regression model revealed a negative relationship between ARR and GFR with a coefficient of -2.08, 95% confidence interval: -4.6, 0.21, P = 0.07. CKD population with HTN tends to have a very high level of ARR, and those with advanced CKD have higher ARR. However, high ARR could have low eGFR and kidney dysfunction on follow-up. In view of high prevalence of noncommunicable disease and high early CKD population, there is an important need to consider comprehensive management strategies that involve the blockage of high renin-angiotensin-aldosterone and the use of mineralocorticosteroid receptor blockers.

Lipocalin-2 derived from adipose tissue mediates aldosterone-induced renal injury

Lipocalin-2 is not only a sensitive biomarker, but it also contributes to the pathogenesis of renal injuries. The present study demonstrates that adipose tissue-derived lipocalin-2 plays a critical role in causing both chronic and acute renal injuries. Four-week treatment with aldosterone and high salt after uninephrectomy (ANS) significantly increased both circulating and urinary lipocalin-2, and it induced glomerular and tubular injuries in kidneys of WT mice. Despite increased renal expression of lcn2 and urinary excretion of lipocalin-2, mice with selective deletion of lcn2 alleles in adipose tissue (Adipo-LKO) are protected from ANS- or aldosterone-induced renal injuries. By contrast, selective deletion of lcn2 alleles in kidney did not prevent aldosterone- or ANS-induced renal injuries. Transplantation of fat pads from WT donors increased the sensitivity of mice with complete deletion of Lcn2 alleles (LKO) to aldosterone-induced renal injuries. Aldosterone promoted the urinary excretion of a human lipocalin-2 variant, R81E, in turn causing renal injuries in LKO mice. Chronic treatment with R81E triggered significant renal injuries in LKO, resembling those observed in WT mice following ANS challenge. Taken in conjunction, the present results demonstrate that lipocalin-2 derived from adipose tissue causes acute and chronic renal injuries, largely independent of local lcn2 expression in kidney.

Cardiovascular Disease Consequences of CKD

Chronic kidney disease, defined as reduced glomerular filtration rate (estimated using serum creatinine- and/or serum cystatin C-based equations) or excess urinary protein excretion, affects approximately 13% of adult Americans and is linked to a variety of clinical complications. Although persons with end-stage renal disease requiring chronic dialysis therapy experience a substantially high cardiovascular burden, whether mild-to-moderate chronic kidney disease is an independent risk factor for fatal and nonfatal cardiovascular events has been more controversial. This review evaluates the current evidence about the clinical and subclinical cardiovascular consequences associated with chronic kidney disease of varying levels of severity. In addition, it discusses the predictors of adverse cardiovascular outcomes while also focusing on recent insights into the relationships between chronic kidney disease and cardiovascular disease from the Chronic Renal Insufficiency Cohort study, a large current prospective cohort study of adults from across the spectrum of chronic kidney disease.

Aldosterone, Renin, Cardiovascular Events, and All-Cause Mortality Among African Americans: The Jackson Heart Study

OBJECTIVES

This study examined the association of aldosterone and plasma renin activity (PRA) with incident cardiovascular disease (CVD), using a composite endpoint of coronary heart disease, stroke, and/or heart failure and mortality among African Americans in the Jackson Heart Study.

BACKGROUND

There is a paucity of data for the association of aldosterone and PRA with incident CVD or all-cause mortality among community-dwelling African Americans.

METHODS

A total of 4,985 African American adults, 21 to 94 years of age, were followed for 12 years. Aldosterone, PRA, and cardiovascular risk factors were collected at baseline (from 2000 to 2004). Incident events included coronary heart disease and stroke (assessed from 2000 to 2011) and heart failure (assessed from 2005 to 2011). Cox models were used to estimate hazard ratios (HRs) for incident CVD and mortality, adjusting for age, sex, education, occupation, current smoking, physical activity, dietary intake, and body mass index.

RESULTS

Among 4,160 participants without prevalent CVD over a median follow-up of 7 years, there were 322 incident CVD cases. In adjusted analyses, each 1-U SD increase in log-aldosterone and log-PRA were associated with HR of 1.26 (95% confidence intervals [CI]: 1.14 to 1.40) and 1.16 (95% CI: 1.02 to 1.33) for incident CVD, respectively. Over a median of 8 years, 513 deaths occurred among 4,985 participants. In adjusted analyses, each 1-U SD increase in log-aldosterone and log-PRA were associated with HRs of 1.13 (95% CI: 1.04 to 1.23) and 1.12 (95% CI: 1.01 to 1.24) for mortality, respectively.

CONCLUSIONS

Elevated aldosterone and PRA may play a significant role in the development of CVD and all-cause mortality among African Americans.

Aldosterone breakthrough in dogs with naturally occurring myxomatous mitral valve disease

INTRODUCTION

Aldosterone breakthrough (ABT) is the condition in which angiotensin converting enzyme inhibitors (ACEIs) and/or angiotensin receptor blockers fail to effectively suppress the activity of the renin angiotensin aldosterone system. The objective of this study was to determine if ABT occurs in dogs with naturally occurring myxomatous mitral valve disease receiving an ACEI, using the urine aldosterone to creatinine ratio (UAldo:C) as a measure of renin angiotensin aldosterone system activation.

ANIMALS, MATERIALS AND METHODS

This study includes 39 dogs with myxomatous mitral valve disease. A UAldo:C cut-off definition (derived from a normal population of healthy, adult, and client-owned dogs) was used to determine the prevalence of ABT in this population. Spearman analysis and univariate logistic regression were used to evaluate the relationship between UAldo:C and ABT (yes/no) and eight variables (age, serum K⁺ concentration, serum creatinine concentration, ACEI therapy duration and ACEI dosage, furosemide therapy duration and furosemide dosage, and urine sample storage time). Finally, the UAldo:C in dogs receiving spironolactone, as part congestive heart failure (CHF) therapy, was compared to dogs with CHF that were not receiving spironolactone.

RESULTS

The prevalence of ABT was 32% in dogs with CHF and 30% in dogs without CHF. There was no relationship between either the UAldo:C or the likelihood of ABT and the eight variables. Therapy with spironolactone lead to a significant elevation of the UAldo:C.

DISCUSSION

Using the UAldo:C and a relatively stringent definition of ABT, it appears that incomplete RAAS blockade is common in dogs with MMVD receiving an ACEI. The prevalence of ABT in this canine population mirrors that reported in humans. While the mechanism of ABT is likely multifactorial and still poorly understood, the proven existence of ABT in dogs offers the potential to improve the prognosis for MMVD with the addition of a mineralocorticoid receptor blocker to current therapeutic regimens.

CONCLUSIONS

Approximately 30% of dogs being treated for heart disease and CHF satisfied the definition of ABT. Identifying patient subpopulations experiencing ABT may help guide future study design and clinical decision-making.

Altered relation of the renin-aldosterone system and vasoactive peptides in type 2 diabetes: The KORA F4 study

BACKGROUND AND AIMS

The exact mechanism of premature atherosclerosis in diabetes is still unclear. Inappropriate activation of the renin-aldosterone-angiotensin system may be an important risk factor for cardiovascular disease. We investigated whether renin and aldosterone are associated with vasoactive peptides midregional-pro atrial natriuretic peptide (MR-proANP) and midregional-pro adrenomedullin (MR-proADM), or with intima media thickness (IMT) as a marker for early atherosclerotic alterations in the general community and in subjects with type 2 diabetes.

METHODS

In 1261 participants in the KORA F4 study, the associations of renin, aldosterone and aldosterone to renin ratio with MR-proANP, MR-proADM and IMT were assessed using linear regression models stratified for the presence of prediabetes and type 2 diabetes.

RESULTS

After adjustment for confounding factors, an inverse association of MR-proANP with renin (p = 0.002) and aldosterone (p = 0.021) and a direct association of MR-proADM with renin (p < 0.001) and aldosterone (p = 0.019) were seen in nondiabetic individuals. In diabetic subjects, there was no significant correlation of MR-proANP or MR-proADM with renin or aldosterone. Renin and aldosterone were not directly associated with IMT in non-diabetic subjects and the total cohort, whereas aldosterone was associated with IMT in diabetic participants (p = 0.005).

CONCLUSIONS

This study shows associations between renin, aldosterone and MR-proANP/MR-proADM plasma levels that are altered in type 2 diabetes. Plasma renin and aldosterone are not independent biomarkers for early atherosclerotic damages of the carotid arteries in the general community.

Reduction of cardiovascular risk in chronic kidney disease by mineralocorticoid receptor antagonism

Cardiovascular disease is the leading cause of death and morbidity in people with chronic kidney disease, but there are few evidence-based treatments for reducing cardiovascular events in these patients. The failure of novel drug candidates to delay progression to end-stage renal disease and limit or abrogate cardiovascular morbidity and mortality has led to increased interest in a mineralocorticoid receptor (MR) antagonist-based treatment model to reduce cardiovascular risk in patients with chronic kidney disease and end-stage renal disease. Aldosterone concentrations and MR signalling are associated with an enhanced risk of cardiovascular injury and the incidence of sudden death, and MR blockade decreases the risk of cardiovascular events and sudden death in patients with reduced glomerular filtration rate. Since evidence from clinical trials shows that treatment with MR antagonists confers a morbidity and mortality advantage for patients with cardiovascular disorders, similar benefits might also accrue in patients with chronic kidney disease. Large prospective trials are urgently needed to answer this question. In this Review, I argue that despite differences in the pathophysiology and clinical features of cardiovascular disease in patients with and without chronic kidney disease, MR antagonists could provide cardiovascular benefit in patients with chronic kidney disease.

Aldosterone, mortality, cardiovascular events and reverse epidemiology in end stage renal disease

BACKGROUND

Plasma aldosterone is markedly increased in end stage renal disease (ESRD). The relationship between aldosterone, all-cause and cardiovascular (CV) mortality in observational studies performed so far is controversial.

DESIGN

We investigated the relationship between aldosterone, mortality and CV events in multivariate analyses including nutrition status, inflammation, LV function and fluids volume biomarkers in 278 ESRD patients without heart failure at baseline.

RESULTS

In univariate analyses aldosterone was an inverse predictor of death (3rd tertile vs. 1st tertile Hazard ratios (HR): 0·58; 95% confidence interval (CI) 0·38-0·90. P = 0·01) and CV events (HR: 0·63; 95% CI 0·41-0·96; P = 0·03). Data adjustment for inflammation and malnutrition biomarkers substantially reduced the inverse relationship between aldosterone, mortality and CV events to be largely not significant (P = 0·31 and P = 0·36, respectively). The same was true by adjusting for volume expansion and LV dysfunction (left atrial volume and atrial natriuretic peptide) biomarkers (P = 0·30 for both outcomes). In a model adjusting for the full set of biomarkers of protein energy wasting/inflammation and volume expansion/LV dysfunction the inverse relationship between aldosterone and death and CV events was nullified (HR for death 0·98, P = 0·93; HR for CV events 0·96, P = 0·87).

CONCLUSIONS

Aldosterone is an inverse predictor of mortality and CV events in ESRD patients. This seemingly paradoxical relationship is abolished by statistical adjustment for inflammation, protein energy malnutrition, and volume expansion biomarkers indicating that it is the mere expression of the confounding effect of these factors. A clinical trial is needed to establish if aldosterone antagonism may improve clinical outcomes in ESRD.

Management of hypertension in chronic kidney disease

Hypertension is a common comorbidity in patients with impaired kidney function. The kidney exerts a marked degree of control over blood pressure through various mechanisms, such as by regulating sodium balance and hormone secretion through the activity of the renin-angiotensin system. The kidney is susceptible to injury, and if already damaged can be at risk of further loss of function as a consequence of elevated blood pressure. Once elevated blood pressure is identified, a combination of sensible lifestyle measures, such as sodium restriction and weight loss, with pharmacological intervention to reduce blood pressure will usually achieve blood pressure goals. In this Review, we outline the importance of blood pressure control for patients with chronic kidney disease (CKD), the mechanisms that affect blood pressure control, and the basis for non-drug and drug therapies. We further discuss the rationale for <140 mmHg systolic and <90 mmHg diastolic targets for blood pressure in patients with CKD, with consideration for tighter targets in the setting of proteinuria.

Electrocardiographic Measures and Prediction of Cardiovascular and Noncardiovascular Death in CKD

Limited studies have assessed the resting 12-lead electrocardiogram (ECG) as a screening test in intermediate risk populations. We evaluated whether a panel of common ECG parameters are independent predictors of mortality risk in a prospective cohort of participants with CKD. The Chronic Renal Insufficiency Cohort (CRIC) study enrolled 3939 participants with eGFR<70 ml/min per 1.73 m(2) from June 2003 to September 2008. Over a median follow-up of 7.5 years, 750 participants died. After adjudicating the initial 497 deaths, we identified 256 cardiovascular and 241 noncardiovascular deaths. ECG metrics were independent risk markers for cardiovascular death (hazard ratio, 95% confidence interval): PR interval ≥200 ms (1.62, 1.19-2.19); QRS interval 100-119 ms (1.64, 1.20-2.25) and ≥120 ms (1.75, 1.17-2.62); corrected QT (QTc) interval ≥450 ms in men or ≥460 ms in women (1.72, 1.19-2.49); and heart rate 60-90 beats per minute (1.21, 0.89-1.63) and ≥90 beats per minute (2.35, 1.03-5.33). Most ECG measures were stronger markers of risk for cardiovascular death than for all-cause mortality or noncardiovascular death. Adding these intervals to a comprehensive model of cardiorenal risk factors increased the C-statistic for cardiovascular death from 0.77 to 0.81 (P<0.001). Furthermore, adding ECG metrics to the model adjusted for standard risk factors resulted in a net reclassification of 12.1% (95% confidence interval 8.1%-16.0%). These data suggest common ECG metrics are independent risk factors for cardiovascular death and enhance the ability to predict death events in a population with CKD.

Plasma aldosterone and its relationship with left ventricular mass in hypertensive patients with early-stage chronic kidney disease

Plasma aldosterone concentrations (PACs) are often increased in the advanced stages of chronic kidney disease (CKD); however, PAC has not been fully investigated in early CKD. Moreover, little is known about the relationship between aldosteronemia and left ventricular (LV) mass in subjects with mild-to-moderate CKD. The study objectives were to analyze PAC, LV mass (LVM), LV geometry and their relationships, in a group of hypertensive patients with stage I-III CKD. One hundred ninety-five hypertensive patients with stage I-III CKD were enrolled and compared with a control group of 82 hypertensive patients without renal dysfunction. LVM was higher in subjects with CKD than in the control group and increased progressively with advancing stages of CKD (P=0.004). A similar trend was observed for PAC (P<0.0001), in which PAC was greater in CKD subjects with LV concentric geometry than in those with eccentric LV hypertrophy (P=0.01). Furthermore, in CKD patients, PAC was directly and significantly correlated with LVM (r=0.29; P<0.0001) and with relative wall thickness (RWT; r=0.36; P<0.0001). These associations remained significant even after adjustment for various confounding factors in multiple regression analyses (P<0.001). In summary, the results demonstrated that in CKD hypertensive patients, LVM, RWT and PAC are increased and related to each other from the earliest stages of renal dysfunction. Furthermore, it seems biologically plausible to speculate that aldosterone may promote a concentric geometry of the left ventricle and increase LVM in hypertensive patients with early CKD.