The effect of combination treatment with aliskiren and blockers of the renin-angiotensin system on hyperkalaemia and acute kidney injury: systematic review and meta-analysis

A randomized, double-blind, placebo-controlled, phase IIa, clinical study on investigating the efficacy and safety of SPH3127 tablet in patients with essential hypertension

Around 70% of patients diagnosed with hypertension exhibit increased levels of renin. SPH3127, an inventive renin inhibitor, has shown favorable tolerability and sustained pharmacodynamic inhibitory impact on plasma renin activity (PRA) during previous phase I trials. This phase II study was conducted to investigate the efficacy and safety of SPH3127 in patients with essential hypertension. This study was conducted in patients with mild to moderate essential hypertension, utilizing a randomized, double-blind, placebo-controlled design. The patients were administered either tablet of SPH3127 at doses of 50 mg, 100 mg, or 200 mg, or a placebo. A total of 122 patients were included in the study, with 121 patients included in the full analysis set. Among these patients, there were 30 individuals in each subgroup receiving different dosage regimens of SPH3127, and 31 patients in the placebo group. The reductions in mean sitting diastolic blood pressure (msDBP) after 8 weeks compared to baseline were 5.7 ± 9.5, 8.6 ± 8.8, and 3.8 ± 10.6 mmHg in the SPH3127 50-, 100-, and 200 mg groups, respectively. In the placebo group, the reduction was 3.1 ± 8.4 mmHg. The corresponding reductions in mean sitting systolic blood pressure (msSBP) were 11.8 ± 13.0, 13.8 ± 11.2, 11.1 ± 13.1, and 7.7 ± 9.7 mmHg in each respective group. SPH3127 is a promising drug for the treatment of patients with essential hypertension. The recommended dosage is 100 mg daily.Clinical trial registration: This study was registered in ClinicalTrials.gov (NCT03756103).

Quantitative Proteomics Combined with Network Pharmacology Analysis Unveils the Biological Basis of Schisandrin B in Treating Diabetic Nephropathy

BACKGROUND

Diabetic nephropathy (DN) is a major complication of diabetes. Schisandrin B (Sch) is a natural pharmaceutical monomer that was shown to prevent kidney damage caused by diabetes and restore its function. However, there is still a lack of comprehensive and systematic understanding of the mechanism of Sch treatment in DN.

OBJECTIVE

We aim to provide a systematic overview of the mechanisms of Sch in multiple pathways to treat DN in rats.

METHODS

Streptozocin was used to build a DN rat model, which was further treated with Sch. The possible mechanism of Sch protective effects against DN was predicted using network pharmacology and was verified by quantitative proteomics analysis.

RESULTS

High dose Sch treatment significantly downregulated fasting blood glucose, creatinine, blood urea nitrogen, and urinary protein levels and reduced collagen deposition in the glomeruli and tubule-interstitium of DN rats. The activities of superoxide dismutase (SOD) and plasma glutathione peroxidase (GSH-Px) in the kidney of DN rats significantly increased with Sch treatment. In addition, the levels of IL-6, IL-1β, and TNF-α were significantly reduced in DN rats treated with Sch. 11 proteins that target both Sch and DN were enriched in pathways such as MAPK signaling, PI3K-Akt signaling, renal cell carcinoma, gap junction, endocrine resistance, and TNF signaling. Furthermore, quantitative proteomics showed that Xaf1 was downregulated in the model vs. control group and upregulated in the Sch-treated vs. model group. Five proteins, Crb3, Tspan4, Wdr45, Zfp512, and Tmigd1, were found to be upregulated in the model vs. control group and downregulated in the Sch vs. model group. Three intersected proteins between the network pharmacology prediction and proteomics results, Crb3, Xaf1, and Tspan4, were identified.

CONCLUSION

Sch functions by relieving oxidative stress and the inflammatory response by regulating Crb3, Xaf1, and Tspan4 protein expression levels to treat DN disease.

Blood Levels of Angiotensinogen and Hypertension in the Multi-Ethnic Study of Atherosclerosis (MESA)

BACKGROUND

Angiotensinogen is the proximal precursor of the angiotensin peptide hormones of the renin-angiotensin-aldosterone system (RAAS). Clinical trials are ongoing targeting angiotensinogen for the treatment of hypertension and heart failure. The epidemiology of angiotensinogen is not well defined, particularly its relationship to ethnicity, sex, and blood pressure (BP)/hypertension.

OBJECTIVES

The authors sought to determine the relationship of circulating angiotensinogen levels to ethnicity, sex, BP, incident hypertension, and prevalent hypertension in a modern sex-balanced ethnically diverse cohort.

METHODS

Plasma angiotensinogen levels were measured in 5,786 participants from the MESA (Multi-Ethnic Study of Atherosclerosis). Linear, logistic, and Cox proportional hazards models were utilized to examine the associations of angiotensinogen with BP, prevalent hypertension, and incident hypertension, respectively.

RESULTS

Angiotensinogen levels were significantly higher in females than males and differed across self-reported ethnicities with the ordering (from highest to lowest): White, Black, Hispanic, and Chinese adults. Higher levels were associated with higher BP and odds of prevalent hypertension, after adjusting for other risk factors. Equivalent relative differences in angiotensinogen were associated with greater differences in BP in males vs females. In males not taking RAAS-blocking medications, a standard deviation increment in log-angiotensinogen was associated with 2.61 mm Hg higher systolic BP (95% CI: 1.49-3.80), while in females the same increment in angiotensinogen was associated with 0.97 mm Hg higher systolic BP (95% CI: 0.30-1.65).

CONCLUSIONS

Significant differences in angiotensinogen levels are present between sexes and ethnicities. A positive association is present between levels and prevalent hypertension and BP, which differs between sexes.

Efficacy of Direct Renin Inhibitors in Slowing Down the Progression of Diabetic Kidney Disease: A Meta-Analysis

Albuminuria is a risk factor for chronic kidney disease and cardiovascular events in diabetic people. The pathogenic processes in these circumstances have been documented to be significantly influenced by enhanced renin-angiotensin system activity. The current meta-analysis was carried out to assess the efficacy of direct renin inhibitors in preventing the progression of diabetic kidney disease. This meta-analysis was conducted as per the guidelines of the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA). We searched the relevant medical literature through PubMed, Cochrane library and EMBASE. The primary efficacy outcome was a percentage change in urine albumin-creatinine ratio (UACR) (in mg/g) level. Other primary efficacy outcomes included remission from microalbuminuria to normal albuminuria and progression from microalbuminuria to macroalbuminuria. Four randomized control studies were identified and included in the current meta-analysis involving 9,609 participants. The use of direct renin inhibitors was superior in reducing mean UACR compared to angiotensin receptor blockers and angiotensin-converting enzyme inhibitors. The pooled mean difference in UACR between direct renin inhibitors and the control group was 9.42% (95% CI: -15.70 to -3.15: p-value=0.003). The odds of progression from microalbuminuria to normal albuminuria are 1.26 times higher in patients receiving direct renin inhibitors compared to patients in the control group (OR: 1.26, 95% CI: 1.08-1.46, p-value=0.002). The odds of remission from microalbuminuria to macroalbuminuria were 20% lower in patients receiving direct renin inhibitors compared to patients in the control group (OR: 0.80, 95% CI: 0.69-0.93, p-value=0.003). The use of aliskiren is associated with a significant reduction in UACR, increased remission from microalbuminuria to normal albuminuria and decreased progression from microalbuminuria to macroalbuminuria.

Antihypertensive agents: a long way to safe drug prescribing in children

Recently updated clinical guidelines have highlighted the gaps in our understanding and management of pediatric hypertension. With increased recognition and diagnosis of pediatric hypertension, the use of antihypertensive agents is also likely to increase. Drug selection to treat hypertension in the pediatric patient population remains challenging. This is primarily due to a lack of large, well-designed pediatric safety and efficacy trials, limited understanding of pharmacokinetics in children, and unknown risk of prolonged exposure to antihypertensive therapies. With newer legislation providing financial incentives for conducting clinical trials in children, along with publication of pediatric-focused guidelines, literature available for antihypertensive agents in pediatrics has increased over the last 20 years. The objective of this article is to review the literature for safety and efficacy of commonly prescribed antihypertensive agents in pediatrics. Thus far, the most data to support use in children was found for angiotensin-converting enzyme inhibitors (ACE-I), angiotensin receptor blockers (ARB), and calcium channel blockers (CCB). Several gaps were noted in the literature, particularly for beta blockers, vasodilators, and the long-term safety profile of antihypertensive agents in children. Further clinical trials are needed to guide safe and effective prescribing in the pediatric population.

Evolution of Patiromer Use: a Review

PURPOSE OF REVIEW

The purpose of this review is to present data from clinical trials that resulted in the key data supporting the use of patiromer as a potassium binder in clinical practice today.

RECENT FINDINGS

In addition to trials that support the current Food and Drug Administration label and published over the past 3 years, the recently published Spironolactone With Patiromer in the Treatment of Resistant Hypertension in Chronic Kidney Disease (AMBER) trial provides clear benefits of patiromer use in a group of resistant hypertension patients. The AMBER was a phase 2, multicenter, randomized, double-blind, parallel-group, placebo-controlled study that evaluated 295 participants stratified by local serum potassium measurement (4.3 to < 4.7 mmol/L vs 4.7 to 5.1 mmol/L) and history of diabetes and chronic kidney disease. The focus was on enabling participants with resistant hypertension to achieve blood pressure goals by using spironolactone. Additionally, the ongoing Patiromer for the Management of Hyperkalemia in Subjects Receiving RAASi Medications for the Treatment of Heart Failure (DIAMOND) trial is designed to demonstrate how patiromer is an "enabler" of therapies that are needed to either control resistant hypertension or reduce mortality in heart failure but generate hyperkalemia. These and other studies are discussed in detail. Patiromer is one of two new potassium binders that are far better tolerated than the previous agent and can be given chronically to participants who need life-saving therapies but have elevations of potassium into a dangerous range as a consequence.

Therapeutic Renin Inhibition in Diabetic Nephropathy-A Review of the Physiological Evidence

The purpose of this systematic review was to investigate the scientific evidence to support the use of direct renin inhibitors (DRIs) in diabetic nephropathy (DN). MEDLINE was searched for articles reported until 2018. A standardized dataset was extracted from articles describing the effects of DRIs on plasma renin activity (PRA) in DN. A total of three clinical articles studying PRA as an outcome measure for DRIs use in DN were identified. These clinical studies were randomized controlled trials (RCTs): one double-blind crossover, one post hoc of a double-blind and placebo-controlled study, and one open-label and parallel-controlled study. Two studies reported a significant decrease of albuminuria associated with PRA reduction. One study had a DRI as monotherapy compared with placebo, and two studies had DRI as add-in to an angiotensin II (Ang II) receptor blocker (ARB). Of 10,393 patients with DN enrolled in five studies with DRI, 370 (3.6%) patients had PRA measured. Only one preclinical study was identified that determined PRA when investigating the effects of aliskiren in DN. Moreover, most of observational preclinical and clinical studies identified report on a low PRA or hyporeninemic hypoaldosteronism in DM. Renin inhibition has been suggested for DN, but proof-of-concept studies for this are scant. A small number of clinical and preclinical studies assessed the PRA effects of DRIs in DN. For a more successful translational research for DRIs, specific patient population responsive to the treatment should be identified, and PRA may remain a biomarker of choice for patient stratification.

DEEPScreen: high performance drug-target interaction prediction with convolutional neural networks using 2-D structural compound representations

The identification of physical interactions between drug candidate compounds and target biomolecules is an important process in drug discovery. Since conventional screening procedures are expensive and time consuming, computational approaches are employed to provide aid by automatically predicting novel drug-target interactions (DTIs). In this study, we propose a large-scale DTI prediction system, DEEPScreen, for early stage drug discovery, using deep convolutional neural networks. One of the main advantages of DEEPScreen is employing readily available 2-D structural representations of compounds at the input level instead of conventional descriptors that display limited performance. DEEPScreen learns complex features inherently from the 2-D representations, thus producing highly accurate predictions. The DEEPScreen system was trained for 704 target proteins (using curated bioactivity data) and finalized with rigorous hyper-parameter optimization tests. We compared the performance of DEEPScreen against the state-of-the-art on multiple benchmark datasets to indicate the effectiveness of the proposed approach and verified selected novel predictions through molecular docking analysis and literature-based validation. Finally, JAK proteins that were predicted by DEEPScreen as new targets of a well-known drug cladribine were experimentally demonstrated in vitro on cancer cells through STAT3 phosphorylation, which is the downstream effector protein. The DEEPScreen system can be exploited in the fields of drug discovery and repurposing for in silico screening of the chemogenomic space, to provide novel DTIs which can be experimentally pursued. The source code, trained "ready-to-use" prediction models, all datasets and the results of this study are available at ; https://github.com/cansyl/DEEPscreen.

Fiend and friend in the renin angiotensin system: An insight on acute kidney injury

Besides assisting the maintenance of blood pressure and sodium homeostasis, the renin-angiotensin system (RAS) plays a pivotal role in pathogenesis of acute kidney injury (AKI). The RAS is equipped with two arms i) the pressor arm composed of Angiotensin II (Ang II)/Angiotensin converting enzyme (ACE)/Angiotensin II type 1 receptor (AT1R) also called conventional RAS, and ii) the depressor arm consisting of Angiotensin (1-7) (Ang 1-7)/Angiotensin converting enzyme 2 (ACE2)/MasR known as non-conventional RAS. Activation of conventional RAS triggers oxidative stress, inflammatory, hypertrophic, apoptotic, and pro-fibrotic signaling cascades which promote AKI. The preclinical and clinical studies have reported beneficial as well as deleterious effects of RAS blockage either by angiotensin receptor blocker or ACE inhibitor in AKI. On the contrary, the depressor arm opposes the conventional RAS, has beneficial effects on the kidney but has been less explored in pathogenesis of AKI. This review focuses on significance of RAS in pathogenesis of AKI and provides better understanding of novel and possible therapeutic approaches to combat AKI.

Hyperkalemia in the Hypertensive Patient

PURPOSE OF REVIEW

Hyperkalemia develops in a patient with systemic arterial hypertension (HTN) if one or more risk factors are present, namely chronic kidney disease (CKD) (especially severe stage 4-5 CKD), diabetes mellitus (DM), heart failure (HF), or pharmacological therapies that interfere with potassium homeostasis, mainly through renin-angiotensin-aldosterone inhibition (RAASi). Hyperkalemia is a considerable reason of morbidity (emergency department (ED) visits and hospitalizations) and portends a higher mortality risk in patients at risk; for instance, hyperkalemia increases the risk of mortality within 1 day of a hyperkalemic event. This review aims to identify the risk factors for high-serum potassium, highlight the risk versus benefit of RAASi in certain patient populations, and outline preventive as well as therapeutic strategies for hyperkalemia.

RECENT FINDINGS

A growing body of evidence supports the safety and efficacy of cation-exchange resins, patiromer, or sodium zirconium cyclosilicate, in patients with a compelling indication for RAASi, yet in whom such therapy was complicated by hyperkalemia, allowing these patients to benefit from continued RAASi therapy. In summary, novel cation exchange polymers present the clinician with a new and safe strategy to address hyperkalemia in patients with a compelling indication for ongoing RAASi therapy instead of withdrawal of such therapy.

Effects of aliskiren on mortality, cardiovascular outcomes and adverse events in patients with diabetes and cardiovascular disease or risk: A systematic review and meta-analysis of 13,395 patients

BACKGROUND

Aliskiren was shown to increase adverse events in patients with diabetes and concomitant renin-angiotensin blockade. We aim to investigate the efficacy and safety of aliskiren in patients with diabetes and increased cardiovascular risk or established cardiovascular disease.

METHODS

MEDLINE and Embase were searched for prospective studies comparing addition of aliskiren to standard medical therapy in patients with diabetes and cardiovascular disease, or ⩾1 additional cardiovascular risk factor (hypertension, abnormal lipid profile, microalbuminuria/proteinuria, chronic kidney disease). Relative risk for efficacy (all-cause mortality, combined cardiovascular mortality and hospitalisation) and safety (hyperkalaemia, hypotension, renal impairment) outcomes was calculated.

RESULTS

Of 2151 studies identified in the search, seven studies enrolling 13,395 patients were included. Aliskiren had no effect on all-cause mortality (relative risk: 1.05, 95% confidence interval: 0.90 to 1.24, p = 0.53), or combined cardiovascular mortality or heart failure hospitalisation (relative risk: 1.07, 95% confidence interval: 0.81 to 1.40, p = 0.64). Patients receiving aliskiren had a greater risk of developing hyperkalaemia (relative risk: 1.32, 95% confidence interval: 1.14 to 1.53, p = 0.0003) and renal impairment (relative risk: 1.15, 95% confidence interval: 1.02 to 1.30, p = 0.03), but not hypotension.

CONCLUSION

Patients with diabetes and cardiovascular disease or cardiovascular risk do not benefit from the addition of aliskiren to standard medical therapy. Detrimental safety profile in pooled analysis supports current warnings.

Evaluation of the Potential for Drug Interactions With Patiromer in Healthy Volunteers

INTRODUCTION

Patiromer is a potassium-binding polymer that is not systemically absorbed; however, it may bind coadministered oral drugs in the gastrointestinal tract, potentially reducing their absorption.

METHODS

Twelve randomized, open-label, 3-period, 3-sequence crossover studies were conducted in healthy volunteers to evaluate the effect of patiromer (perpetrator drug) on absorption and single-dose pharmacokinetics (PK) of drugs (victims) that might be commonly used with patiromer. Subjects received victim drug alone, victim drug administered together with patiromer 25.2 g (highest approved dose), and victim drug administered 3 hours before patiromer 25.2 g. The primary PK endpoints were area under the curve (AUC), extrapolated to infinity (AUC0-∞), and maximum concentration ( Cmax). Results were reported as 90% confidence intervals (CIs) about the geometric mean AUC0-∞ and Cmax ratios with prespecified equivalence limits of 80% to 125%.

RESULTS

Overall, 370 subjects were enrolled, with 365 receiving ≥1 dose of patiromer; 351 subjects completed the studies and all required treatments. When coadministered with patiromer, the 90% CIs for AUC0-∞ remained within 80% to 125% for 9 drugs (amlodipine, cinacalcet, clopidogrel, furosemide, lithium, metoprolol, trimethoprim, verapamil, and warfarin). The AUC0-∞ point estimate ratios for levothyroxine and metformin with patiromer coadministration were ≥80%, with the lower bounds of the 90% CIs at 76.8% and 72.8%, respectively. For ciprofloxacin, the point estimate for AUC0-∞ was 71.5% (90% CI: 65.3-78.4). For 8 of 12 drugs, point estimates for Cmax were ≥80% with patiromer coadministration; for ciprofloxacin, clopidogrel, metformin, and metoprolol, the point estimates were <80%. When patiromer was administered 3 hours after each victim drug, the 90% CIs for AUC0-∞ and Cmax for each drug were within the prespecified 80% to 125% limits.

CONCLUSION

For 9 of the 12 drugs coadministered with patiromer, there were no clinically significant drug-drug interactions. For 3 drugs (ciprofloxacin, levothyroxine, and metformin), a 3-hour separation between patiromer and their administration resulted in no clinically significant drug-drug interactions.

Aliskiren therapy in hypertension and cardiovascular disease: a systematic review and a meta-analysis

The efficacy and safety of aliskiren combination therapy with angiotensin converting enzyme inhibitors (ACEIs) or angiotensin receptor blockers (ARBs) in patients with hypertension and cardiovascular disease remains attractive attention. We searched the Cochrane Central Register, the Clinical Trials Registry, EMBASE, MEDLINE and PubMed for relevant literatures up to January 2017. A total of 13 randomized controlled trials (RCTs) with 12222 patients were included in this study, and the combined results indicated that aliskiren in combination therapy with ACEIs or ARBs had remarkable effects in reducing systolic blood pressure (SBP) [weighted mean differences (WMD), -4.20; 95% confidential intervals (CI) -5.44 to -2.97; I² , 29.7%] and diastolic blood pressure (DBP: WMD, -2.09; 95% CI -2.90 to -1.27; I² , 0%) when compared with ACEIs or ARBs monotherapy, but with significantly increased the risk of hyperkalaemia [relative risk (RR), 1.45; 95% CI 1.28 to 1.64; I² ,10.6 %] and kidney injury ( RR, 1.92; 95% CI 1.14 to 3.21; I² , 0%). Besides, there was no significant difference in the incidence of major cardiovascular events (RR, 0.95; 95% CI 0.89 to 1.02; I² , 0%) between the combined therapy and ACEIs or ARBs monotherapy. In conclusion, this meta-analysis demonstrated that aliskiren in combination therapy with ACEs/ARBs could control BP effectively, but is associated with increasing risks of hyperkalaemia and kidney injury, and have no benefit in preventing of major cardiovascular events.

Blood pressure lowering efficacy of renin inhibitors for primary hypertension

BACKGROUND

Hypertension is a chronic condition associated with an increased risk of mortality and morbidity. Renin is the enzyme responsible for converting angiotensinogen to angiotensin I, which is then converted to angiotensin II. Renin inhibitors are a new class of drugs that decrease blood pressure (BP) by preventing the formation of both angiotensin I and angiotensin II.

OBJECTIVES

To quantify the dose-related BP lowering efficacy of renin inhibitors compared to placebo in the treatment of primary hypertension.To determine the change in BP variability, pulse pressure, and heart rate and to evaluate adverse events (mortality, non-fatal serious adverse events, total adverse events, withdrawal due to adverse effects and specific adverse events such as dry cough, diarrhoea and angioedema).

SEARCH METHODS

The Cochrane Hypertension Information Specialist searched the following databases for randomized controlled trials (RCTs) up to February 2017: the Cochrane Hypertension Specialized Register, the Cochrane Central Register of Controlled Trials (CENTRAL) (2017, Issue 2), MEDLINE (from 1946), Embase (from 1974), the World Health Organization International Clinical Trials Registry Platform, and ClinicalTrials.gov. There was no restriction by language or publication status. We also searched the European Medicines Agency (EMA) for clinical study reports, the Novartis Clinical Study Results Database, bibliographic citations from retrieved references, and contacted authors of relevant papers regarding further published and unpublished work.

SELECTION CRITERIA

We included randomized, double-blinded, placebo-controlled studies evaluating BP lowering efficacy of fixed-dose monotherapy with renin inhibitor compared with placebo for a minimum duration of three to 12 weeks in adult patients with primary hypertension.

DATA COLLECTION AND ANALYSIS

This systematic review is a comprehensive update which includes four additional studies and extensive detail from nine clinical study reports (CSRs) of previously included studies obtained from EMA. The remaining three CSRs are not available.Two review authors independently assessed study eligibility and extracted data. In all cases where there was a difference between the CSR and the published report, data from the CSR was used. Dichotomous outcomes were reported as risk ratio (RR) with 95% confidence intervals (CIs) and continuous outcomes as mean difference (MD) with 95% CIs.

MAIN RESULTS

12 studies (mean duration of eight weeks) in 7439 mostly Caucasian patients (mean age 54 years) with mild-to-moderate uncomplicated hypertension were eligible for inclusion in the review. Aliskiren was the only renin inhibitor evaluated. All included studies were assessed to have high likelihood of attrition, reporting and funding bias.Aliskiren has a dose-related systolic/diastolic blood pressure (SBP/DBP) lowering effect as compared with placebo MD with 95% CI: aliskiren 75 mg (MD -2.97, 95% CI -4.76 to -1.18)/(MD -2.05, 95% CI -3.13 to -0.96) mm Hg (moderate-quality evidence), aliskiren 150 mg (MD -5.95, 95% CI -6.85 to -5.06)/ (MD -3.16, 95% CI -3.74 to -2.58) mm Hg (moderate-quality evidence), aliskiren 300 mg (MD -7.88, 95% CI -8.94 to -6.82)/ (MD -4.49, 95% CI -5.17 to -3.82) mm Hg (moderate-quality evidence), aliskiren 600 mg (MD -11.35, 95% CI -14.43 to -8.27)/ (MD -5.86, 95% CI -7.73 to -3.99) mm Hg (low-quality evidence). There was a dose-dependent decrease in blood pressure for aliskiren 75 mg, 150 mg and 300 mg. The blood pressure lowering effect of aliskiren 600 mg was not different from 300 mg (MD -0.61, 95% CI -2.78 to 1.56)/(MD -0.68, 95% CI -2.03 to 0.67). Aliskiren had no effect on blood pressure variability. Due to very limited information available regarding change in heart rate and pulse pressure, it was not possible to meta-analyze these outcomes.Mortality and non-fatal serious adverse events were not increased. This review found that in studies of eight week duration aliskiren may not increase withdrawal due to adverse events (low-quality evidence). Diarrhoea was increased in a dose-dependent manner (RR 7.00, 95% CI 2.48 to 19.72) with aliskiren 600 mg (low-quality evidence). The most frequent adverse events reported were headache, nasopharyngitis, diarrhoea, dizziness and fatigue.

AUTHORS' CONCLUSIONS

Compared to placebo, aliskiren lowered BP and this effect is dose-dependent. This magnitude of BP lowering effect is similar to that for angiotensin-converting enzyme (ACE) inhibitors and angiotensin receptor blockers (ARBs). There is no difference in mortality, nonfatal serious adverse events or withdrawal due to adverse effects with short term aliskiren monotherapy. Diarrhoea was considerably increased with aliskiren 600 mg.

Antihypertensive Properties of a Pea Protein Hydrolysate during Short- and Long-Term Oral Administration to Spontaneously Hypertensive Rats

This study investigated short-term (24 h) and long-term (5 wk) systolic blood pressure (SBP)-lowering effects in spontaneously hypertensive rats (SHR) of a 5 kDa membrane pea protein hydrolysate permeate (PPH-5) produced through thermoase hydrolysis of pea protein isolate (PPI). Amino acid analysis showed that the PPH-5 had lower contents of sulfur-containing amino acids than the PPI. Size-exclusion chromatography indicated mainly low molecular weight (<10 kDa) peptides in PPH-5 but not in the PPI. The PPH-5 had renin and angiotensin converting enzyme inhibition IC50 values of 0.57 and 0.10 mg/mL (P < 0.05), respectively, and consisted mainly of peptides with 2 to 6 amino acids. Mass spectrometry analysis revealed mainly hydrophilic tetrapeptide sequences. After a single oral administration (100 mg/kg body weight) to SHR, the unheated PPI showed weakest (P < 0.05) SBP-lowering effect with a -4 mm Hg maximum when compared to -25 mm Hg for heat-treated PPI and -36 mm Hg for PPH-5. Incorporation of the PPH-5 as 0.5% or 1% (w/w) casein substitute in the SHR diet produced maximum SBP reductions of -22 or -26 mm Hg (P < 0.05), respectively after 3 wk. In comparison, the unhydrolyzed PPI produced a maximum SBP reduction of -17 mm Hg also after 3 wk. Potency of the pea products decreased in the 4th and 5th wk, though SBP values of the treated rats were still lower than the untreated control. We conclude that the antihypertensive potency of PPH-5 may have been due to the presence of easily absorbed hydrophilic peptides.

An additive effect of eplerenone to ACE inhibitor on slowing the progression of diabetic nephropathy in the db/db mice

Although blockade of the renin-angiotensin-system (RAS) has become standard therapy for diabetic nephropathy (DN), decline in kidney function towards end-stage renal disease is seen in many patients. Elevated plasma aldosterone often accompanies RAS blockade by a phenomenon known as "aldosterone escape" and activates the mineralocorticoid receptor (MR). We therefore examined whether addition of the MR antagonist eplerenone to an ACEI would enhance the efficacy in slowing the progression of DN. Untreated uninephrectomized diabetic db/db mice developed progressive albuminuria and glomerulosclerosis between weeks 18 and 22, associated with decreased number of podocytes and increased renal expression of fibrotic markers. The therapeutic effect of eplerenone at 100 mg/kg BW/d on albuminuria, podocyte injury and renal fibrosis was similar to that of enalapril given alone at maximally effective doses. Adding eplerenone to enalapril resulted in further reduction in these measurements. Renal expressions of TNF-α, MCP-1, Nox2 and p47phox and renal TBARS levels, markers of inflammation and oxidative stress, were increased during disease progression in diabetic mice, which were reduced by eplerenone or enalapril given alone and further reduced by the two drugs given in combination. However, there were no treatment related effects on plasma K+. Our results suggest that eplerenone is effective in slowing the progression of DN in db/db mice and that the effect is additive to an ACEI. The addition of an MR antagonist void of effects on plasma K+ to an ACEI may offer additional renoprotection in progressive DN via blocking the effects of aldosterone due to escape or diabetes-induction.

Kinetics of the inhibition of renin and angiotensin I-converting enzyme by cod (Gadus morhua) protein hydrolysates and their antihypertensive effects in spontaneously hypertensive rats

Background

Cod muscle has a balanced protein profile that contains potentially bioactive amino acid sequences. However, there is limited information on release of these peptides from the parent proteins and their ability to modulate mammalian blood pressure.

Objective

The aim of this study was to generate cod antihypertensive peptides with potent in vitro inhibitory effects against angiotensin-converting enzyme (ACE) and renin. The most active peptides were then tested for systolic blood pressure (SBP)-reducing ability in spontaneously hypertensive rats (SHRs).

Design

Cod protein hydrolysate (CPH) was produced by subjecting the muscle proteins to proteolysis first by pepsin and followed by trypsin+chymotrypsin combination. In order to enhance peptide activity, the CPH was subjected to reverse-phase (RP)-HPLC separation to yield four fractions (CF1, CF2, CF3, and CF4). The CPH and RP-HPLC fractions were each tested at 1 mg/mL for ability to inhibit in vitro ACE and renin activities. CPH and the most active RP-HPLC fraction (CF3) were then used for enzyme inhibition kinetics assays followed by oral administration (200 and 30 mg/kg body weight for CPH and CF3, respectively) to SHRs and SBP measurements within 24 h.

Results

The CPH, CF3, and CF4 had similar ACE-inhibitory activities of 84, 85, and 87%, which were significantly (p<0.05) higher than the values for CF1 (69%) and CF2 (79%). Conversely, the CF3 had the highest (63%) renin-inhibitory activity (p<0.05) when compared to CPH (43%), CF1 (15%), and CF4 (44%). CPH and CF3 exhibited uncompetitive mode of ACE inhibition, whereas renin inhibition was non-competitive. Even at a 6.7-fold lower dosage, the CF3 significantly (p<0.05) reduced SBP (maximum −40.0 mmHg) better than CPH (maximum −19.1 mmHg).

Conclusions

RP-HPLC fractionation led to enhanced antihypertensive effects of cod peptides, which may be due to a stronger renin-inhibitory activity.

Renin-Angiotensin-Aldosterone System Blockade in Diabetic Nephropathy. Present Evidences

Diabetic Kidney Disease (DKD) is the leading cause of chronic kidney disease in developed countries and its prevalence has increased dramatically in the past few decades. These patients are at an increased risk for premature death, cardiovascular disease, and other severe illnesses that result in frequent hospitalizations and increased health-care utilization. Although much progress has been made in slowing the progression of diabetic nephropathy, renal dysfunction and the development of end-stage renal disease remain major concerns in diabetes. Dysregulation of the renin-angiotensin-aldosterone system (RAAS) results in progressive renal damage. RAAS blockade is the cornerstone of treatment of DKD, with proven efficacy in many arenas. The theoretically-attractive option of combining these medications that target different points in the pathway, potentially offering a more complete RAAS blockade, has also been tested in clinical trials, but long-term outcomes were disappointing. This review examines the “state of play” for RAAS blockade in DKD, dual blockade of various combinations, and a perspective on its benefits and potential risks.

Role of the Renin-Angiotensin-Aldosterone System and Its Pharmacological Inhibitors in Cardiovascular Diseases: Complex and Critical Issues

Hypertension is one of the major risk factor able to promote development and progression of several cardiovascular diseases, including left ventricular hypertrophy and dysfunction, myocardial infarction, stroke, and congestive heart failure. Also, it is one of the major driven of high cardiovascular risk profile in patients with metabolic complications, including obesity, metabolic syndrome and diabetes, as well as in those with renal disease. Thus, effective control of hypertension is a key factor for any preventing strategy aimed at reducing the burden of hypertension-related cardiovascular diseases in the clinical practice. Among various regulatory and contra-regulatory systems involved in the pathogenesis of cardiovascular and renal diseases, renin-angiotensin system (RAS) plays a major role. However, despite the identification of renin and the availability of various assays for measuring its plasma activity, the specific pathophysiological role of RAS has not yet fully characterized. In the last years, however, several notions on the RAS have been improved by the results of large, randomized clinical trials, performed in different clinical settings and in different populations treated with RAS inhibiting drugs, including angiotensin converting enzyme (ACE) inhibitors and antagonists of the AT1 receptor for angiotensin II (ARBs). These findings suggest that the RAS should be considered to have a central role in the pathogenesis of different cardiovascular diseases, for both therapeutic and preventive purposes, without having to measure its level of activation in each patient. The present document will discuss the most critical issues of the pathogenesis of different cardiovascular diseases with a specific focus on RAS blocking agents, including ACE inhibitors and ARBs, in the light of the most recent evidence supporting the use of these drugs in the clinical management of hypertension and hypertension-related cardiovascular diseases.

Treatment of hypertension in children with chronic kidney disease

Hypertension (HTN) is increasingly recognized as a common feature of pediatric chronic kidney disease (CKD). A growing body of evidence demonstrates that HTN is both underdiagnosed and undertreated in this population. The consequences of untreated HTN include adverse effects on CKD progression, markers of cardiovascular morbidity, and neurocognitive functioning. Consensus guidelines issued over the past decade have incorporated recent research on the consequences of HTN in recommendations for the diagnosis and treatment of HTN in pediatric CKD and include lower BP targets. Agents which target the renin-angiotensin-aldosterone system (RAAS) should be considered first-line therapy in CKD-associated HTN in children, though multiple medications may be required to achieve sufficient BP control.

Drug therapy of apparent treatment-resistant hypertension: focus on mineralocorticoid receptor antagonists

Apparent treatment-resistant hypertension (aTRH) is defined as blood pressure (BP) >140/90 mmHg despite three different antihypertensive drugs including a diuretic. aTRH is associated with an increased risk of cardiovascular events, including stroke, chronic renal failure, myocardial infarction, congestive heart failure, aortic aneurysm, atrial fibrillation, and sudden death. Preliminary studies of renal nerve ablation as a therapy to control aTRH were encouraging. However, these results were not confirmed by the Symplicity 3 trial. Therefore, attention has refocused on drug therapy. Secondary forms of hypertension and associated conditions such as obesity, sleep apnea, and primary aldosteronism are common in patients with aTRH. The pivotal role of aldosterone in the pathogenesis of aTRH in many cases is well recognized. For patients with aTRH, the Joint National Committee-8, the European Society of Hypertension, and a recent consensus conference recommend that a diuretic, ACE inhibitor, or angiotensin receptor blocker and calcium channel blocker combination be used to maximally tolerated doses before starting a 'fourth-line' drug such as a mineralocorticoid receptor (MR) antagonist. Although the best fourth-line drug for aTRH has not been extensively investigated, a number of studies summarized here show that an MR antagonist is effective in reducing BP when added to the standard multi-drug regimen.

Normal 25-Hydroxyvitamin D Levels Are Associated with Less Proteinuria and Attenuate Renal Failure Progression in Children with CKD

Angiotensin-converting enzyme inhibitors (ACEi) for renin-angiotensin-aldosterone system (RAAS) blockade are routinely used to slow CKD progression. However, vitamin D may also promote renoprotection by suppressing renin transcription through cross-talk between RAAS and vitamin D-fibroblast growth factor-23 (FGF-23)-Klotho pathways. To determine whether vitamin D levels influence proteinuria and CKD progression in children, we performed a post hoc analysis of the Effect of Strict Blood Pressure Control and ACE Inhibition on Progression of CKD in Pediatric Patients (ESCAPE) cohort. In 167 children (median eGFR 51 ml/min per 1.73 m(2)), serum 25-hydroxyvitamin D (25(OH)D), FGF-23, and Klotho levels were measured at baseline and after a median 8 months on ACEi. Children with lower 25(OH)D levels had higher urinary protein/creatinine ratios at baseline (P=0.03) and at follow-up (P=0.006). Levels of 25(OH)D and serum vitamin D-binding protein were not associated, but 25(OH)D ≤50 nmol/L associated with higher diastolic BP (P=0.004). ACEi therapy also associated with increased Klotho levels (P<0.001). The annualized loss of eGFR was inversely associated with baseline 25(OH)D level (P<0.001, r=0.32). Five-year renal survival was 75% in patients with baseline 25(OH)D ≥50 nmol/L and 50% in those with lower 25(OH)D levels (P<0.001). This renoprotective effect remained significant but attenuated with ACEi therapy (P=0.05). Renal survival increased 8.2% per 10 nmol/L increase in 25(OH)D (P=0.03), independent of eGFR; proteinuria, BP, and FGF-23 levels; and underlying renal diagnosis. In children with CKD, 25(OH)D ≥50 nmol/L was associated with greater preservation of renal function. This effect was present but attenuated with concomitant ACEi therapy.

Efficacy of aliskiren, compared with angiotensin II blockade, in slowing the progression of diabetic nephropathy in db/db mice: should the combination therapy be a focus?

Although the intensive use of angiotensin II blockade (ACEI or ARB), progression of diabetic nephropathy is common. A feedback increase in renin production often accompanies angiotensin II blockade. We therefore examined whether aliskiren, a direct renin inhibitor, confers better renoprotection than angiotensin II blockade and whether the addition of aliskiren to an ACEI or ARB would enhance the efficacy in slowing the progression of glomerulosclerosis in diabetes. Untreated db/db mice developed progressive mesangial matrix expansion and albuminuria between weeks 18 and 22, associated with reduction of WT-1 immunopositive podocytes and nephrin and podocin production and induction of desmin and B7-1 generation and renal expression of TGFß1, PAI-1, fibronectin and type IV collagen. Treatment with aliskiren at 30 mg/kg/d inhibited the increases in albuminuria and markers of renal fibrosis and the changes that are indicative of podocyte injury seen in the db/db mice. Notably, the therapeutic effect of aliskiren was similar to that of either enalapril or valsartan given alone at maximally effective doses. Combined therapy caused the loss of 10% ~ 16.6% of db/db mice, yielded no further reduction in renal fibrosis and podocyte injury but further reduced albuminuria and renal production of TNFα, Nox2 and p47phox and urine MCP-1 and malondialdehyde levels, the markers of renal inflammation and oxidative stress. These results suggest that aliskiren, enalapril and valsartan are equally effective in slowing the progression of diabetic nephropathy. The use of combination therapy with aliskiren and ACEI/ARB may not be strongly supported.

Combination therapy in chronic kidney disease?

The renin-angiotensin system (RAS) plays a fundamental role in preserving the circulation and yet, it may be injurious to heart and blood vessels and may also allow, and sometimes hasten, kidney disease progression. Thus, effective RAS inhibition may be a major pharmacologic necessity to control hypertension, to decrease cardiovascular complication, and to inhibit kidney disease progression. Unfortunately, the beneficial effects attained in the management of renal disease sometimes are incomplete. The reasons for these inadequate outcomes may include angiotensin escape or excessive local angiotensin production. Two pharmacologic strategies have been proposed to overcome this drawback including higher than recommended doses of RAS inhibitors and the combination of two different RAS inhibitors. However, three large studies have shown that these more intensive pharmacologic approaches should be treated with caution when applied to high-risk patients, as organ perfusion may fall to critical levels that may cause severe complications. Nevertheless, intensive RAS inhibition (including combination therapy) may be the sole alternative in patients with chronic kidney disease (CKD) in whom other therapeutics options have failed. In these cases, adequate precautions including close clinical and laboratory follow up should prevent major complications.

Acute kidney injury: an acceptable risk of treatment with renin-angiotensin system blockade in primary care?

Background

Use of renin-angiotensin system (RAS) blockade has become increasingly widespread driven by evidence-based guidance. There is concern about the role of these agents in the genesis of avoidable acute kidney injury (AKI).

Objectives

To investigate the association between AKI and use of RAS blockade.

Design

Multilevel hierarchical analysis of a large cohort of patients registered with UK general practitioners.

Setting

Primary care practices in East and West Kent, United Kingdom.

Patients

244,715 patients from 27 practices.

Measurements

Demographic, clinical, biochemical and prescription data.

Methods

Analyses of data acquired between 02/3/2004 and 17/04/2012 using multilevel logistic regression to determine the relationship between AKI and use of RAS blockade; further analysed by indication for treatment with RAS blockade.

Results

Sufficient serum creatinine data were available to define AKI in 63,735 patients with 208,275 blood test instances. In 95,569 instances the patient was prescribed a RAS antagonist of which 5.4% fulfilled criteria for AKI. The unadjusted odds ratio (OR) for AKI in those prescribed RAS blockade was 1.93 (1.81-2.06, 95%CI) falling to 1.11 (1.02-1.20, 95%CI) when adjusted for age, gender, co-morbidity, GFR category, proteinuria, systolic blood pressure and diuretic therapy. In patients with an evidence-based indication there was no difference in absolute risk of AKI. However, prescription of RAS blockade in the absence of indication appeared to be associated with greater risk of AKI.

When analysis was repeated with AKIN2/AKIN3 as the outcome, although risk of AKI remained significant when unadjusted (OR 1.73, 95%CI 1.42-2.11, p<0.001), after full adjustment there was no increased risk (OR 0.83, 95%CI 0.63-1.09) in those taking RAS antagonists. However, when analysed by indication AKIN2/AKIN3 was significantly more likely in those prescribed RAS antagonists without indication (OR 2.04, 95%CI 1.41-2.94, p<0.001).

Limitations

Observational database study. No information concerning hospitalisation. Prescribing assumptions and potential inaccurate coding. Potential survival bias; patients surviving longer will contribute more data.

Conclusions

Use of RAS antagonists increased the risk of AKI, independent of common confounding variables. After correction for confounders the risk fell away and became non-significant for moderate and severe AKI. However, where there was no evidence-based indication for RAS antagonists the risk of AKI, whether mild, moderate or severe, remained greater.

Effect of aliskiren on cardiovascular outcomes in patients with prehypertension: a meta-analysis of randomized controlled trials

BACKGROUND

Aliskiren is a widely used therapy for patients with hypertension, however, the effect of aliskiren on major cardiovascular outcomes is a matter of debate. The aim of this study is to evaluate the effects of aliskiren therapy on major cardiovascular outcomes by this meta-analysis of randomized controlled trials.

METHODS

We searched PubMed, EmBase, and the Cochrane Central Register of Controlled Trials for relevant literature. All eligible studies were randomized controlled trials assessing the effect of aliskiren therapy compared with patients without aliskiren therapy. Relative risks (RRs) with 95% confidence intervals (CIs) were used to measure the effect of aliskiren therapy on major cardiovascular outcomes with a random-effect model.

RESULTS

We included six trials reporting data on 12,465 patients. These studies reported 1,886 occurrences of major cardiovascular events, 1,074 events of total mortality, 739 events of cardiac death, 366 events of myocardial infarction, and 319 events of stroke. Aliskiren therapy had no effect on major cardiovascular events (RR, 0.93; 95% CI: 0.77-1.13; P=0.47), total mortality (RR, 1.00; 95% CI: 0.77-1.29; P=1.00), cardiac death (RR, 1.01; 95% CI: 0.79-1.29; P=0.95), myocardial infarction (RR, 0.71; 95% CI: 0.36-1.38; P=0.31), or stroke (RR, 0.87; 95% CI: 0.48-1.58; P=0.64).

CONCLUSION

Aliskiren therapy does not have an effect on the incidence of major cardiovascular events, total mortality, cardiac death, myocardial infarction, or stroke.

Oxidative stress and early atherosclerosis: novel antioxidant treatment

Atherosclerotic lesions initiate in regions characterized by low shear stress and reduced activity of endothelial atheroprotective molecules such as nitric oxide, which is the key molecule managing vascular homeostasis. The generation of reactive oxygen species from the vascular endothelium is strongly related to various enzymes, such as xanthine oxidase, endothelial nitric oxide synthase and nicotinamide-adenine dinucleotide phosphate oxidase. Several pharmaceutical agents, including angiotensin converting enzyme inhibitors, angiotensin receptors blockers and statins, along with a variety of other agents, have demonstrated additional antioxidant properties beyond their principal role. Reports regarding the antioxidant role of vitamins present controversial results, especially those based on large scale studies. In addition, there is growing interest on the role of dietary flavonoids and their potential to improve endothelial function by modifying the oxidative stress status. However, the vascular-protective role of flavonoids and especially their antioxidant properties are still under investigation. Indeed, further research is required to establish the impact of the proposed new therapeutic strategies in atherosclerosis.

Aliskiren, the first direct renin inhibitor: assessing a role in pediatric hypertension and kidney diseases

This article provides a review of the role of aliskiren, a direct renin inhibitor, in pediatric hypertension and kidney diseases. Among the many mechanisms involved in regulating blood pressure, the renin-angiotensin-aldosterone system (RAAS) plays a major role. Additionally, the RAAS has been identified as a contributing factor to cardiovascular and renal diseases for more than three decades. The potential benefits of inhibiting the RAAS by aliskiren alone or in combination with other RAAS blockers (ACEIs, ARBs) seem to be theoretically promising. However, caution should be exercised in treating children, especially in those with significant chronic kidney disease until there is more evidence regarding the safety and efficacy of this new drug in the pediatric population from ongoing clinical trials.

Renin inhibitors in diabetes and hypertension: an update

The coexistence of hypertension and diabetes increases the incidence of cardiovascular events and long-term morbidity and mortality. Blood pressure should be controlled with the most appropriate drugs as well as tight blood glucose control in patients with diabetes and hypertension. RAAS (Renin Angiotensin Aldosterone System) blockers have an important role in the treatment of these patients, in this sense, ACEi and ARB remained the major treatment option in hypertension guidelines. The most recent RAAS blocker to be approved by the FDA was aliskiren in 2007, a renin inhibitor. Studies showed that aliskiren is as effective as other antihypertensive drugs and has a safety profile similar to placebo. The potent renin inhibitor aliskiren directly inhibits the RAAS system at its rate limiting step and differently from other RAAS blockers; it decreases plasma renin activity (PRA). Although the relationship of increased PRA levels and cardiovascular risk has been shown, it is unclear if the PRA decrease provided by aliskiren has an impact on clinical outcomes and cardiovascular endpoints. On the other hand, large trials like ASPIRE, AVANT-GARDE, ALTITUDE, ASTRONAUT, which investigated the combination of aliskiren with other RAAS blockers, failed to show the expected outcomes or resulted with an increased incidence of adverse effects, which raised more questions. As a result of the ALTITUDE trial, combination of aliskiren with an ACEi or ARB is not recommended in patients with hypertension and diabetes, or at least moderate renal dysfunction. Trials designed to prove aliskiren's efficacy in new indications like diabetes, may face similar problems related to dual RAAS blockade because in the majority of cases, the optimal treatment is achieved with an ACEi or ARB. In this conjuncture, the increase in adverse events seen with aliskiren might be related to dual RAAS blockade rather than aliskiren directly. For instance, it is unclear whether the adverse event incidence would be the same, less, or higher if ALTITUDE was designed to investigate ACEi and ARB combination without aliskiren. In fact, every new molecular entity and mechanism of action faces the same barriers. For the time being, differentiating points like PRA lowering effects as an add-on therapy to calcium channel blockers or hydrochlorothiazide, and the populations that might have additional benefit, should be carefully investigated.

Aliskiren - an alternative to angiotensin-converting enzyme inhibitors or angiotensin receptor blockers in the therapy of arterial hypertension

There has been enormous progress in antihypertensive therapy over the last few decades. However, the management of arterial hypertension is still insufficient and more efforts are needed to improve both non-pharmacological and pharmacological treatment of this widely prevalent disease. Renin-angiotensin-aldosterone system (RAAS) inhibition is crucial both for blood pressure (BP) control and for prevention of organ damage or its development in patients with hypertension. Angiotensin-converting enzyme inhibitors and/or sartans block RAAS incompletely. Aliskiren is one of the novel drugs that has been introduced to antihypertensive therapy recently. Up to now no trial has confirmed that aliskiren is efficacious in reducing cardiovascular events. Double RAAS blockade with aliskiren was not always safe. This review article presents the current view on the place of aliskiren in the therapy of arterial hypertension.

Aliskiren ameliorates pressure overload-induced heart hypertrophy and fibrosis in mice

AIM

Aliskiren (ALK) is a renin inhibitor that has been used in the treatment of hypertension. The aim of this study was to determine whether ALK could ameliorate pressure overload-induced heart hypertrophy and fibrosis, and to elucidate the mechanisms of action.

METHODS

Transverse aortic constriction (TAC) was performed in mice to induce heart pressure overload. ALK (150 mg·kg(-1)·d(-1), po), the autophagy inhibitor 3-methyladenine (10 mg·kg(-1) per week, ip) or the PKCβI inhibitor LY333531 (1 mg·kg(-1)·d-(1), po) was administered to the mice for 4 weeks. Heart hypertrophy, fibrosis and function were evaluated based on echocardiography, histological and biochemical measurements. Mechanically stretched cardiomyocytes of rats were used for in vitro experiments. The levels of signaling proteins were measured using Western blotting, while the expression of the relevant genes was analyzed using real-time QRT-PCR.

RESULTS

TAC induced marked heart hypertrophy and fibrosis, accompanied by high levels of Ang II in plasma and heart, and by PKCβI/α and ERK1/2 phosphorylation in heart. Meanwhile, TAC induced autophagic responses in heart, i.e. increases in autophagic structures, expression of Atg5 and Atg16 L1 mRNAs and LC3-II and Beclin-1 proteins. These pathological alterations in TAC-mice were significantly ameliorated or blocked by ALK administration. In TAC-mice, 3-methyladenine administration also ameliorated heart hypertrophy, fibrosis and dysfunction, while LY333531 administration inhibited ERK phosphorylation and autophagy in heart. In mechanically stretched cardiomyocytes, CGP53353 (a PKCβI inhibitor) prevented ERK phosphorylation and autophagic responses, while U0126 (an ERK inhibitor) blocked autophagic responses.

CONCLUSION

ALK ameliorates heart hypertrophy, fibrosis and dysfunction in the mouse model in setting of chronic pressure overload, via suppressing Ang II-PKCβI-ERK1/2-regulated autophagy.

Kinetics and molecular docking studies of the inhibitions of angiotensin converting enzyme and renin activities by hemp seed (Cannabis sativa L.) peptides

Four novel peptide sequences (WVYY, WYT, SVYT, and IPAGV) identified from an enzymatic digest of hemp seed proteins were used for enzyme inhibition kinetics and molecular docking studies. Results showed that WVYY (IC50 = 0.027 mM) was a more potent (p < 0.05) ACE-inhibitory peptide than WYT (IC50 = 0.574 mM). However, WYT (IC50 = 0.054 mM) and SVYT (IC50 = 0.063 mM) had similar renin-inhibitory activity, which was significantly better than that of IPAGV (IC50 = 0.093 mM). Kinetics studies showed that WVYY had a lower inhibition constant (Ki) of 0.06 mM and hence greater affinity for ACE when compared to the 1.83 mM obtained for WYT. SVYT had lowest Ki value of 0.89 mM against renin, when compared to the values obtained for WYT and IPAGV. Molecular docking results showed that the higher inhibitory activities of WVYY and SVYT were due to the greater degree of noncovalent bond-based interactions with the enzyme protein, especially formation of higher numbers of hydrogen bonds with active site residues.

Chronic kidney disease: a new look at pathogenetic mechanisms and treatment options

The concept of renoprotection has evolved significantly, driven by improved understanding of the pathophysiology of chronic kidney disease (CKD) and the advent of novel treatment options. Glomerular hyperfiltration, hypertension and proteinuria represent key mediators of CKD progression. It is increasingly recognized that proteinuria may actually be pathological and etiological in CKD progression and not just symptomatic. It initiates a sequence of events involving activation of proinflammatory and profibrotic signaling pathways in proximal tubular epithelial cells with transmission of the disease to the tubulointerstitium and progression to end-stage kidney disease (ESKD). Although the etiology and epidemiology of pediatric CKD differs to that in adults, studies in the various animal models of kidney disease, from obstructive uropathy to glomerulonephritis, have revealed that many common proinflammatory and profibrotic pathways are induced in progressive proteinuric CKD, irrespective of the primary disease. This pathomechanistic overlap therefore translates into the potential for common treatment targets for a wide spectrum of kidney diseases. In this review we therefore discuss the experimental and clinical evidence for an array of prospective future drug treatments of CKD progression. While conceptually promising, clear definitive evidence beyond preclinical data does not exist for many of these treatments, and others are limited by serious adverse effects. More studies are needed before general recommendations can be given.

Sequential RAAS blockade: is it worth the risk?

Soon after the emergence of the renin-angiotensin-aldosterone system (RAAS) blocking treatment as the cornerstone of renoprotective treatment in the prevention and treatment of diabetic and nondiabetic CKD, it was investigated if a higher degree of achievable RAAS blockade by combining more than one compound is feasible and advantageous. Regardless of the benefits from using monotherapy for diabetic kidney disease, there is still much improvement to wish for in terms of kidney prognosis in these populations. A great deal of research has gone into evaluating combinations of the RAAS blocking treatments in different populations and with different drugs and doses. Studies have mostly been short-term and use surrogate endpoints such as albuminuria. Side effects have been well known and expected in terms of increasing potassium levels and hypotension, but to an acceptable extent. With recent disappointing results from major hard endpoint trials using dual RAAS blockade the concept is now under scrutiny. In this review we will discuss the pros and cons of dual RAAS blockade, with facts and findings from smaller studies, endpoint trials, and meta-analyses.

Renin-angiotensin system blocking drugs

The two major classes of drugs that target the RAS are the angiotensin-converting enzyme (ACE) inhibitors and the selective AT1 receptor blockers (ARBs). Although both of these drug classes target angiotensin II, the differences in their mechanisms of action have implications for their effects on other pathways and receptors that may have therapeutic implications. Both ACEIs and ARBs are effective antihypertensive agents that have been shown to reduce the risk of cardiovascular and renal events. Direct inhibition of renin -the most proximal aspect of the RAS -became clinically feasible from 2007 with the introduction of aliskiren. This latter drug has been shown to be efficacious for the management of hypertension. Combined therapy of direct renin-inhibitors with ACEIs or ARBs has been tested in some clinical situations as congestive HF and proteinuria with diverse results. This article tries to offer an updated review of current knowledge on the use of RAS blocking drugs in clinical settings.