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

Is echocardiography mandatory for patients with chronic kidney disease?

This study aims at evaluating the prevalence of left ventricular diastolic dysfunction in a group of 319 hypertensive patients with stage 3b-4-5 chronic kidney disease (according to Kidney Disease Improving Global Outcomes classification), compared with 216 patients with essential hypertension and normal renal function. All patients underwent echocardiographic examination. Patients on stage 1-2-3a chronic kidney disease, dialysis treatment, or with previous manifestations of heart failure or other cardiovascular diseases were excluded. Patients with renal disease had significantly worse diastolic function (both considering trans-mitral flow and tissue Doppler imaging parameters). Diastolic dysfunction is found in 70.5% of the CKD group and in 41.6% of hypertensive patients (p < 0.0001). Multiple regression analysis shows an association between renal function and diastolic function (β 0.223; p < 0.0001), independent of potential confounders. Our study shows that diastolic dysfunction is highly prevalent in patients with advanced chronic kidney disease; we posit that in this population, the risk of diastolic heart failure is very high. We think that patients with a marked decrease of glomerular filtration rate (GFR) must be considered at high risk for diastolic heart failure and should have an echocardiographic examination performed, even if asymptomatic and in the absence of evident cardiovascular disease.

The sirtuin1 gene associates with left ventricular myocardial hypertrophy and remodeling in two chronic kidney disease cohorts: a longitudinal study

BACKGROUND

Oxidative stress and inflammation are major drivers of myocardial hypertrophy in chronic kidney disease (CKD). The silent information regulator gene 1 (Sirt1) is a fundamental mediator of the response to oxidative stress and inflammation and promotes myocardial growth under stress conditions; therefore, it may contribute to myocardial hypertrophy and concentric remodeling of the left ventricle (LV) in CKD.

METHODS

We investigated the cross-sectional and longitudinal relationship between three candidate polymorphisms in the Sirt1 gene and LV parameters in two cohorts of CKD patients including 235 stage G5D patients and 179 stages G1-5 patients, respectively.

RESULTS

In both cohorts, the C allele of the Sirt1 rs7069102 polymorphism associated with the posterior wall thickness in separate and combined analyses (beta = 0.15, P = 2 × 10) but was unrelated with the LV volume and the LV mass index indicating a peculiar association of this allele with LV concentric remodeling. Accordingly, the same allele was linked with the LV mass-to-volume ratio in separate and combined (beta = 0.14, P = 2 × 10) analyses in the same cohorts. Furthermore, in longitudinal analyses patients harboring the C allele showed a more pronounced increase in LV mass-to-volume ratio over time than patients without such an allele (regression coefficient = 0.14, 95% confidence interval: 0.05-0.23; P = 3 × 10 in the combined analysis).

CONCLUSION

The rs7069102 polymorphism in the Sirt1 gene is associated with LV concentric remodeling in two independent cohorts of stages G5D and G1-5 CKD patients. These results offer a genetic basis to the hypothesis that the Sirt1 gene plays a causal role in myocardial hypertrophy and LV concentric remodeling in these patients.

In vivo ameliorative effect of cerium oxide nanoparticles in isoproterenol-induced cardiac toxicity

BACKGROUND

Cerium oxide nanoparticles have gained much more attention especially in the field of nanomedicine. This work represents cerium oxide nanoparticles as a new prophylactic model for heart failure progression.

OBJECTIVE

To investigate the potential protective effect of cerium oxide nanoparticles on Isoproterenol (ISO)-induced cardiac toxicity in rats.

METHODS

Cerium oxide nanoparticles (5±1nm) were synthesized by reverse micelle method and characterized using High Resolution Transmission Electron Microscopy, X-Ray Diffraction and particle size analyzer. The experiments were performed on 96 male Wistar rats. The rats were randomly allocated into eight groups. Namely; two Negative and positive control groups, captopril administered group, Nano-ceria (low dose) group, Nano-ceria (high dose) group, Captopril- Isoproterenol group, Nano-ceria (low dose)-Isoproterenol group and Nano-ceria (high dose)-Isoproterenol group. Cardio toxic rat model was induced by subcutaneous administration of Isoproterenol (ISO) (30mg/kg) for two consecutive days in adult male rats. Two doses (0.5 and 5μg/kg/week) of cerium oxide nanoparticles were applied for five weeks and 50mg/kg/day of Captopril was used as a reference drug. Cardiac marker enzymes, Cortisol and Aldosterone hormones were assessed in serum. Oxidant-antioxidant parameters and histopathological examination in heart tissues were also determined.

RESULTS

These dose of nano-ceria, showed a promising ameliorative and prophylactic effect against cardiac toxicity compared to Captopril reference drug. Serum cardiac markers were decreased by noticeable percentage, CK-MB (50% and 57%), LDH (47% and 57.7%), AST (38% and 36.5%) and ALT (33.5% and 30.6%) for both doses respectively, while increased tissues level of the antioxidant enzymes, catalase (48% - 26%) and superoxide dismutase (64%, 143%).

CONCLUSION

These consistent biochemical and histopathological results suggest that, nano-ceria could be used as effective antioxidant in prophylactic protocols for management of cardiac disorders associated with oxidative stress.

Serum uric acid is not independently associated with plasma renin activity and plasma aldosterone in hypertensive adults

BACKGROUND AND AIMS

In experimental investigations conducted in rats, raising serum uric acid (SUA) levels resulted in the stimulation of intrarenal renin expression. Studies in humans exploring the association of SUA with plasma renin activity (PRA) yielded conflicting results. Moreover, little is known about the relationship of SUA with plasma aldosterone concentration (PAC). The study aimed to assess the relationship between SUA levels, PRA, and PAC and the influence of age, gender, body mass index (BMI), and hyperuricemia on these relationships in subjects with essential hypertension (EH).

METHODS AND RESULTS

We enrolled 372 hypertensive patients (mean age 45 ± 12 years, men 67%) with uncomplicated EH that was not pharmacologically treated. The study population was divided in tertiles according to SUA levels. While PRA did not differ significantly across the three tertiles, PAC was higher in subjects belonging to the uppermost tertile of SUA than those in the lower ones (p = 0.0429); however, this difference lost statistical significance after adjustment for age, sex, BMI, and serum creatinine. Univariate correlation analyses showed significant associations of SUA with PRA (r = 0.137; p = 0.008) and PAC (r = 0.179; p < 0.001). However, these relationships were not significant after correcting for confounding factors in multiple linear regression analyses. We did not observe statistically significant effect modification by gender, age, BMI, and hyperuricemia.

CONCLUSION

SUA levels are weakly associated with PRA and PAC in adults with untreated EH. These relationships were lost after adjustment for age, sex, BMI, and serum creatinine.

The predictive value of different equations for estimation of glomerular filtration rate in patients with coronary artery disease - Results from the AtheroGene study

BACKGROUND

Impaired renal function leads to dramatically increased risk for the development and progression of coronary artery disease (CAD). Therefore we aimed to assess the predictive value of different equations for estimated glomerular filtration rate (eGFR) in CAD-patients.

METHODS

From the AtheroGene study 2135 patients were included. eGFR was calculated using the 4-variable Modification of Diet in Renal Disease (4MDRD) equation for serum creatinine (sCr), the Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) equation for sCr and cystatin C (CysC) each alone, and in combination (CysC/sCr). eGFR was assessed regarding the combined outcome of cardiovascular death and non-fatal myocardial infarction and regarding complex CAD represented by a SYNTAX score ≥23. Median follow-up was 4.3years.

RESULTS

Only the CKD-EPI equation using CysC could differentiate between eGFR >90ml/min/1.73m(2) vs. eGFR 60-90ml/min/1.73m(2) according to the occurrence of an endpoint event (log-rank test p=0.009). In the Cox regression analysis only eGFR calculated by CKD-EPI equation for CysC (Hazard ratio per 1 standard deviation (HR) 1.27 (95% CI 1.07-1.50); p=0.007) and for CysC/sCr (HR 1.22 (95% CI 1.02-1.46); p=0.026) were predictive regarding the outcome after adjustment for cardiovascular risk factors and Nt-proBNP. Furthermore, only eGFR calculated by CKD-EPI equation for CysC (odds ratio (OR) 1.57 (95% CI 1.36-1.78); p<0.001) and for CysC/sCr (OR 1.32 (95% CI 1.13-1.53); p<0.001) were significantly associated with a SYNTAX score ≥23.

CONCLUSION

In patients with CAD the CKD-EPI equation for CysC and for CysC/sCr provided the best predictive value regarding the prognosis and the severity of CAD.

The angiotensin II type 1 receptor-neprilysin inhibitor LCZ696 blocked aldosterone synthesis in a human adrenocortical cell line

A recent clinical study indicated that an angiotensin II (Ang II) type 1 (AT₁) receptor-neprilysin inhibitor (ARNi) designated LCZ696 (sacubitril/valsartan, as combined sodium complex) was superior to enalapril at reducing the risks of death and hospitalization due to heart failure. Therefore, we investigated the possible mechanisms of the beneficial effect of LCZ696, in which the inhibition of neprilysin enhances atrial natriuretic peptide (NP) or brain NP (ANP or BNP)-evoked signals that can block Ang II/AT₁ receptor-induced aldosterone (Ald) synthesis in human adrenocortical cells. The binding affinity of valsartan+LBQ657 (active moiety of sacubitril) to the AT₁ receptor was greater than that of valsartan alone in an AT₁ receptor-expressing human embryonic kidney cell-based assay. There was no difference in the dissociation from the AT₁ receptor between valsartan+LBQ657 and valsartan alone. In Ang II-sensitized human adrenocortical cells, ANP or BNP alone, but not LBQ657 or valsartan alone, significantly decreased Ald synthesis. The level of suppression of Ald synthesis by ANP or BNP with LBQ657 was greater than that by ANP or BNP without LBQ657. The suppression of ANP was blocked by inhibitors of regulator of G-protein signaling proteins and cyclic GMP-dependent protein kinase. The inhibition of neprilysin did not change the mRNA levels of the AT₁ receptor, ANP receptor A, regulator of G-protein signaling protein, renin or 3β-hydroxysteroid dehydrogenases. In conclusion, the inhibition of neprilysin by LBQ657 enhances the NP-evoked signals that can block Ang II/AT₁ receptor-induced Ald synthesis in human adrenocortical cells.

Cellular and Molecular Mechanisms of Chronic Kidney Disease with Diabetes Mellitus and Cardiovascular Diseases as Its Comorbidities

Chronic kidney disease (CKD), diabetes mellitus (DM), and cardiovascular diseases (CVD) are complex disorders of partly unknown genesis and mostly known progression factors. CVD and DM are the risk factors of CKD and are strongly intertwined since DM can lead to both CKD and/or CVD, and CVD can lead to kidney disease. In recent years, our knowledge of CKD, DM, and CVD has been expanded and several important experimental, clinical, and epidemiological associations have been reported. The tight cellular and molecular interactions between the renal, diabetic, and cardiovascular systems in acute or chronic disease settings are becoming increasingly evident. However, the (patho-) physiological basis of the interactions of CKD, DM, and CVD with involvement of multiple endogenous and environmental factors is highly complex and our knowledge is still at its infancy. Not only single pathways and mediators of progression of these diseases have to be considered in these processes but also the mutual interactions of these factors are essential. The recent advances in proteomics and integrative analysis technologies have allowed rapid progress in analyzing complex disorders and clearly show the opportunity for new efficient and specific therapies. More than a dozen pathways have been identified so far, including hyperactivity of the renin-angiotensin (RAS)-aldosterone system, osmotic sodium retention, endothelial dysfunction, dyslipidemia, RAS/RAF/extracellular-signal-regulated kinase pathway, modification of the purinergic system, phosphatidylinositol 3-kinase (PI 3-kinase)-dependent signaling pathways, and inflammation, all leading to histomorphological alterations of the kidney and vessels of diabetic and non-diabetic patients. Since a better understanding of the common cellular and molecular mechanisms of these diseases may be a key to successful identification of new therapeutic targets, we review in this paper the current literature about cellular and molecular mechanisms of CKD.