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Heart failure affects ≈5.7 million people in the United States alone. Angiotensin-converting enzyme inhibitors, angiotensin receptor blockers, β-blockers, and aldosterone antagonists have improved mortality in patients with heart failure and reduced ejection fraction, but mortality remains high. In July 2015, the US Food and Drug Administration approved the first of a new class of drugs for the treatment of heart failure: Valsartan/sacubitril (formerly known as LCZ696 and currently marketed by Novartis as Entresto) combines the angiotensin receptor blocker valsartan and the neprilysin inhibitor prodrug sacubitril in a 1:1 ratio in a sodium supramolecular complex. Sacubitril is converted by esterases to LBQ657, which inhibits neprilysin, the enzyme responsible for the degradation of the natriuretic peptides and many other vasoactive peptides. Thus, this combined angiotensin receptor antagonist and neprilysin inhibitor addresses 2 of the pathophysiological mechanisms of heart failure: activation of the renin-angiotensin-aldosterone system and decreased sensitivity to natriuretic peptides. In the Prospective Comparison of ARNI With ACEI to Determine Impact on Global Mortality and Morbidity in Heart Failure (PARADIGM-HF) trial, valsartan/sacubitril significantly reduced mortality and hospitalization for heart failure, as well as blood pressure, compared with enalapril in patients with heart failure, reduced ejection fraction, and an elevated circulating level of brain natriuretic peptide or N-terminal pro-brain natriuretic peptide. Ongoing clinical trials are evaluating the role of valsartan/sacubitril in the treatment of heart failure with preserved ejection fraction and hypertension. We review here the mechanisms of action of valsartan/sacubitril, the pharmacological properties of the drug, and its efficacy and safety in the treatment of heart failure and hypertension.
© 2016 American Heart Association, Inc.
Proteinuria and hyperphosphatemia are cardiovascular risk factors independent of GFR. We hypothesized that proteinuria induces relative phosphate retention via increased proximal tubule phosphate reabsorption. To test the clinical relevance of this hypothesis, we studied phosphate handling in nephrotic children and patients with CKD. Plasma fibroblast growth factor 23 (FGF-23) concentration, plasma phosphate concentration, and tubular reabsorption of phosphate increased during the proteinuric phase compared with the remission phase in nephrotic children. Cross-sectional analysis of a cohort of 1738 patients with CKD showed that albuminuria≥300 mg/24 hours is predictive of higher phosphate levels, independent of GFR and other confounding factors. Albuminuric patients also displayed higher plasma FGF-23 and parathyroid hormone levels. To understand the molecular mechanisms underlying these observations, we induced glomerular proteinuria in two animal models. Rats with puromycin-aminonucleoside-induced nephrotic proteinuria displayed higher renal protein expression of the sodium-phosphate co-transporter NaPi-IIa, lower renal Klotho protein expression, and decreased phosphorylation of FGF receptor substrate 2α, a major FGF-23 receptor substrate. These findings were confirmed in transgenic mice that develop nephrotic-range proteinuria resulting from podocyte depletion. In vitro, albumin did not directly alter phosphate uptake in cultured proximal tubule OK cells. In conclusion, we show that proteinuria increases plasma phosphate concentration independent of GFR. This effect relies on increased proximal tubule NaPi-IIa expression secondary to decreased FGF-23 biologic activity. Proteinuria induces elevation of both plasma phosphate and FGF-23 concentrations, potentially contributing to cardiovascular disease.
Copyright © 2015 by the American Society of Nephrology.
BACKGROUND - Increased systolic blood pressure variability between outpatient visits is associated with increased incidence of cardiovascular end points. However, few studies have examined the association of visit-to-visit variability in systolic blood pressure with clinically relevant kidney disease outcomes. We analyzed the association of systolic blood pressure visit-to-visit variability with renal and cardiovascular morbidity and mortality among individuals with diabetes and nephropathy.
STUDY DESIGN - Observational analysis of IDNT (Irbesartan Diabetic Nephropathy Trial) and the RENAAL (Reduction of End Points in Non-Insulin-Dependent Diabetes With the Angiotensin II Antagonist Losartan) Study.
SETTING & PARTICIPANTS - 2,739 participants with type 2 diabetes and nephropathy with at least 1 year of blood pressure measurements available.
PREDICTORS - Systolic blood pressure visit-to-visit variability was calculated from the SD of the systolic blood pressure from 4 visits occurring 3-12 months postrandomization.
OUTCOMES - The kidney disease outcome was defined as time to confirmed doubling of serum creatinine level, end-stage renal disease, or death; the cardiovascular outcome was defined as time to cardiovascular death, myocardial infarction, stroke, hospitalization for heart failure, or revascularization.
RESULTS - Mean visit-to-visit variability in systolic blood pressure from 3 to 12 months postrandomization was 12.0±6.8(SD)mmHg. Following this ascertainment period, there were 954 kidney disease and 542 cardiovascular events. Greater systolic blood pressure visit-to-visit variability was associated independently with increased risk of the composite kidney disease end point (HR per 1-SD increment, 1.08 [95%CI, 1.01-1.16]; P=0.02) and end-stage renal disease, but not with the cardiovascular outcome.
LIMITATIONS - Observational study with the potential for confounding.
CONCLUSIONS - In diabetic individuals with nephropathy, systolic blood pressure visit-to-visit variability is associated independently with hard kidney disease outcomes.
Copyright © 2014 National Kidney Foundation, Inc. Published by Elsevier Inc. All rights reserved.
BACKGROUND - A doubling of serum creatinine value, corresponding to a 57% decline in estimated glomerular filtration rate (eGFR), is used frequently as a component of a composite kidney end point in clinical trials in type 2 diabetes. The aim of this study was to determine whether alternative end points defined by smaller declines in eGFR would improve the statistical power of these clinical trials.
STUDY DESIGN - Post hoc analyses of 2 multinational randomized controlled trials (Reduction of End Points in Non-Insulin-Dependent Diabetes With the Angiotensin II Antagonist Losartan [RENAAL] and Irbesartan Diabetic Nephropathy Trial [IDNT]) that assessed the treatment effect of the angiotensin receptor blockers (ARBs) losartan and irbesartan.
SETTING & PARTICIPANTS - 1,513 (RENAAL) and 1,715 (IDNT) adult patients with type 2 diabetes and nephropathy.
PREDICTOR - Established versus alternative end points defined as a confirmed doubling of serum creatinine level versus confirmed eGFR decline of 57%, 40%, 30%, or 20% as a component of a composite end point of end-stage renal disease or eGFR < 15mL/min/1.73m(2).
OUTCOMES - Numbers of patients reaching end points, precision (standard error), and significance (z score) of ARB treatment effect (HR) during follow-up.
RESULTS - Lesser eGFR declines resulted in a greater number of patients reaching end points in both treatment groups and lower standard error of the HR, but the effect on z score was counterbalanced by attenuation of the HR. When calculating the eGFR decline from month 3, attenuation of the HR was less pronounced.
LIMITATIONS - Post hoc analysis.
CONCLUSIONS - Despite increases in precision of the treatment effect, eGFR declines less than a doubling of serum creatinine value did not consistently improve statistical power of the clinical trials due to attenuation of the treatment effect. Attenuation of the treatment effect appears to be due in part to acute effects of ARBs on eGFR. These findings should be taken into account when using lesser eGFR declines as alternative end points for clinical trials.
Copyright © 2014 National Kidney Foundation, Inc. Published by Elsevier Inc. All rights reserved.
OBJECTIVES - This study sought to determine the frequency and magnitude of impaired systolic deformation in heart failure with preserved ejection fraction (HFpEF).
BACKGROUND - Although diastolic dysfunction is widely considered a key pathophysiologic mediator of HFpEF, the prevalence of concomitant systolic dysfunction has not been clearly defined.
METHODS - We assessed myocardial systolic and diastolic function in 219 HFpEF patients from a contemporary HFpEF clinical trial. Myocardial deformation was assessed using a vendor-independent 2-dimensional speckle-tracking software. The frequency and severity of impaired deformation was assessed in HFpEF, and compared to 50 normal controls free of cardiovascular disease and to 44 age- and sex-matched hypertensive patients with diastolic dysfunction (hypertensive heart disease) but no HF. Among HFpEF patients, clinical, echocardiographic, and biomarker correlates of left ventricular strain were determined.
RESULTS - The HFpEF patients had preserved left ventricular ejection fraction and evidence of diastolic dysfunction. Compared to both normal controls and hypertensive heart disease patients, the HFpEF patients demonstrated significantly lower longitudinal strain (LS) (-20.0 ± 2.1 and -17.07 ± 2.04 vs. -14.6 ± 3.3, respectively, p < 0.0001 for both) and circumferential strain (CS) (-27.1 ± 3.1 and -30.1 ± 3.5 vs. -22.9 ± 5.9, respectively; p < 0.0001 for both). In HFpEF, both LS and CS were related to LVEF (LS, R = -0.46; p < 0.0001; CS, R = -0.51; p < 0.0001) but not to standard echocardiographic measures of diastolic function (E' or E/E'). Lower LS was modestly associated with higher NT-proBNP, even after adjustment for 10 baseline covariates including LVEF, measures of diastolic function, and LV filling pressure (multivariable adjusted p = 0.001).
CONCLUSIONS - Strain imaging detects impaired systolic function despite preserved global LVEF in HFpEF that may contribute to the pathophysiology of the HFpEF syndrome. (LCZ696 Compared to Valsartan in Patients With Chronic Heart Failure and Preserved Left-ventricular Ejection Fraction; NCT00887588).
Copyright © 2014 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.
Human DNA polymerase kappa (pol κ) is a translesion synthesis (TLS) polymerase that catalyzes TLS past various minor groove lesions including N(2)-dG linked acrolein- and polycyclic aromatic hydrocarbon-derived adducts, as well as N(2)-dG DNA-DNA interstrand cross-links introduced by the chemotherapeutic agent mitomycin C. It also processes ultraviolet light-induced DNA lesions. Since pol κ TLS activity can reduce the cellular toxicity of chemotherapeutic agents and since gliomas overexpress pol κ, small molecule library screens targeting pol κ were conducted to initiate the first step in the development of new adjunct cancer therapeutics. A high-throughput, fluorescence-based DNA strand displacement assay was utilized to screen ∼16,000 bioactive compounds, and the 60 top hits were validated by primer extension assays using non-damaged DNAs. Candesartan cilexetil, manoalide, and MK-886 were selected as proof-of-principle compounds and further characterized for their specificity toward pol κ by primer extension assays using DNAs containing a site-specific acrolein-derived, ring-opened reduced form of γ-HOPdG. Furthermore, candesartan cilexetil could enhance ultraviolet light-induced cytotoxicity in xeroderma pigmentosum variant cells, suggesting its inhibitory effect against intracellular pol κ. In summary, this investigation represents the first high-throughput screening designed to identify inhibitors of pol κ, with the characterization of biochemical and biologically relevant endpoints as a consequence of pol κ inhibition. These approaches lay the foundation for the future discovery of compounds that can be applied to combination chemotherapy.
The effects of angiotensin-converting enzyme (ACE) inhibition and angiotensin II type 1 receptor blockade (ARB) on fibrinolysis and inflammation after cardiopulmonary bypass (CPB) are uncertain. This study tested the hypothesis that ACE inhibition enhances fibrinolysis and inflammation to a greater extent than ARB in patients undergoing CPB. One week to 5 days before surgery, patients were randomized to ramipril 5 mg/day, candesartan 16 mg/day, or placebo. ACE inhibition increased intraoperative bradykinin and tissue-type plasminogen activator (t-PA ) concentrations as compared to AR B. Both ACE inhibition and AR B decreased the need for plasma transfusion relative to placebo, but only ACE inhibition decreased the duration of hospital stay. Neither ACE inhibition nor AR B significantly affected concentrations of plasminogen activator inhibitor-1 (PAI -1), interleukin (IL )-6, IL -8, or IL -10. ACE inhibition enhanced intraoperative fibrinolysis without increasing the likelihood of red-cell transfusion. By contrast, neither ACE inhibition nor ARB affected the inflammatory response. ACE inhibitors and ARBs may be safely continued until the day of surgery.
Biomarkers of oxidative stress and inflammation predict cardiovascular events in maintenance hemodialysis patients. Angiotensin-converting enzyme (ACE) inhibitors and angiotensin-receptor blockers (ARBs) reduce cardiovascular mortality in the general population, but their benefit in maintenance hemodialysis patients is not fully explored. To test whether ACE inhibitors and ARBs differentially affect markers of oxidative stress, inflammation, and fibrinolysis during hemodialysis, we conducted a randomized, double-blind, placebo-controlled 3×3 crossover study. We randomly assigned 15 participants undergoing hemodialysis to placebo, ramipril (5 mg/d), and valsartan (160 mg/d) for 7 days, with a washout period of 3 weeks in between the treatments. On the morning of the seventh day of drug treatment, participants underwent serial blood sampling during hemodialysis. Neither ramipril nor valsartan affected BP during hemodialysis. Ramipril increased IL-1β concentrations (P=0.02) and decreased IL-10 concentrations (P=0.04) compared with placebo. Valsartan and ramipril both lowered IL-6 levels during dialysis (P<0.01 for each compared with placebo). Valsartan increased F(2)-isoprostane levels, and ramipril suggested a similar trend (P=0.09). Valsartan and ramipril both lowered D-dimer levels (P<0.01 for both), whereas only ramipril seemed to prevent a rise in vWf levels (P=0.04). In summary, during hemodialysis, valsartan induces a greater anti-inflammatory effect compared with ramipril, although ramipril seems to prevent dialysis-induced endothelial dysfunction as measured by levels of vWf. A prospective clinical trial is necessary to determine whether ACE inhibitors and ARBs also differ with respect to their effects on cardiovascular mortality in this population.
AIMS - The long-term cardioprotective effect of angiotensin receptor blockers (ARBs) is associated with the short-term lowering of its primary target blood pressure, but also with the lowering of albuminuria. Since the individual blood pressure and albuminuria response to an ARB varies between and within an individual, we tested whether the variability and discordance in systolic blood pressure (SBP) and albuminuria response to ARB therapy are associated with its long-term effect on cardiovascular outcomes.
METHODS AND RESULTS - The combined data of the RENAAL and IDNT trials were used. We first investigated the extent of variability and discordance in SBP and albuminuria response (baseline to 6 months). Subsequently, we assessed the combined impact of residual Month 6 SBP and albuminuria level with cardiovascular outcome. In ARB-treated patients, 421 patients (34.5%) either had a reduction in SBP but no reduction in albuminuria, or vice versa, indicating substantial discordance in response in these parameters. The initial reduction in SBP and albuminuria independently correlated with cardiovascular protection: HR per 5 mmHg SBP reduction 0.97 (95% CI 0.94-0.99) and HR per decrement log albuminuria 0.87 (95% CI 0.76-0.99). Across all SBP categories at Month 6, a progressively lower cardiovascular risk was observed with a lower albuminuria level. This was particularly evident in patients who reached the guideline recommended SBP target of ≤130 mmHg.
CONCLUSION - The SBP and albuminuria response to ARB therapy is variable and discordant. Therapies intervening in the renin-angiotensin-aldosterone system with the aim of improving cardiovascular outcomes may therefore require a dual approach targeting both blood pressure and albuminuria.