Results of Low-Dose Human Atrial Natriuretic Peptide Infusion in Nondialysis Patients With Chronic Kidney Disease Undergoing Coronary Artery Bypass Grafting

Identification of natriuretic peptide receptor A-related gene expression signatures in podocytes in vivo reveals baseline control of protective pathways

Natriuretic peptide receptor-A (NPR-A) is the principal receptor for the natriuretic peptides atrial natriuretic peptide (ANP) and brain natriuretic peptide (BNP). Targeted deletion of NPR-A in mouse glomerular podocytes significantly enhances renal injury in vivo in the DOCA-salt experimental model. It was therefore hypothesized that natriuretic peptides exert a direct protective effect on glomerular barrier integrity through activation of NPR-A and modulation of gene expression patterns in podocytes. Green fluorescence-positive podocytes from mice with a conditional deletion of Npr1 encoding NPR-A were isolated by fluorescence-activated cell sorting (FACS). Differentially expressed genes (DEGs) in podocytes were identified by RNA sequencing of podocytes from wild-type and NPR-A-deleted mice. Enrichment analysis was performed on the DEGs using Gene Ontology (GO) terms. Identified transcripts were validated by real-time PCR and ELISA of cultured isolated human and mouse glomeruli. In addition, the effect of natriuretic peptides on podocyte migration was investigated by measuring the outgrowth of podocytes from cultured glomeruli. A total of 158 DEGs were identified with 81 downregulated DEGs and 77 upregulated DEGs in Npr1-deficient podocytes. Among the downregulated genes were protein S and semaphorin 3G, which are known to have protective effects in podocytes. Protein S was also expressed in and secreted from isolated human glomeruli. GO enrichment analysis revealed that the upregulated DEGs in NPR-A deficient podocytes were associated with cell migration and motility. In line, BNP significantly decreased podocyte outgrowth from cultured glomeruli. In conclusion, endogenous levels of natriuretic peptides in mice support baseline protective pathways at glomerular podocytes such as protein S and suppress podocyte migration.NEW & NOTEWORTHY A combination of fluorescence-activated cell sorting and RNA sequencing identified 158 changed gene products in adult mouse kidneys with and without podocyte-specific deletion of the natriuretic peptide receptor A. Downregulated products included protein S and semaphorin 3G, both with proven renoprotective impact, whereas upregulated products were related to mobility of podocytes. Protein S was produced and released from human and murine isolated glomeruli, and atrial natriuretic peptide (ANP) led to decreased migration of podocytes.

Angiotensin Receptor-Neprilysin Inhibitor Suppresses Renin-Angiotensin-Aldosterone System Activation After Cardiac Surgery Using Cardiopulmonary Bypass

BACKGROUND

Sacubitril/valsartan, being both a neprilysin inhibitor and angiotensin receptor blocker, exhibits a renin-angiotensin-aldosterone system (RAAS) inhibitory effect. However, no study has investigated the administration of sacubitril/valsartan in patients early after surgery using cardiopulmonary bypass.

METHODS AND RESULTS

This was a prospective observational study of 63 patients who underwent open heart surgery and were treated with sacubitril/valsartan. No serious adverse events occurred. Among the 63 patients, sacubitril/valsartan was discontinued in 13 due to hypotension (n=10), renal dysfunction (n=2), and dizziness (n=1). Atrial natriuretic peptide concentrations increased significantly from Day 3 of treatment (P=0.0142 vs. Postoperative Day 1) and remained high thereafter. In contrast, plasma renin activity was significantly suppressed from Day 3 onwards (P=0.00206 vs. Postoperative Day 1). A decrease in creatinine concentrations and an increase in the estimated glomerular filtration rate were observed on Day 3; this improvement in renal function was not observed in the historical control group, in which patients did not receive sacubitril/valsartan. New postoperative atrial fibrillation was less frequent in the study group compared with the historical control (12.7% vs. 38.0%; P=0.0034).

CONCLUSIONS

Sacubitril/valsartan administration was safe immediately after open heart surgery in patients without postoperative hypotension. It enhanced serum atrial natriuretic peptide concentrations and suppressed RAAS activation.

Intraoperative hemodialysis during open-heart surgery in patients with severe chronic kidney disease: a retrospective cohort study

Background

Acute kidney injury and chronic kidney disease (CKD) after cardiac surgery are associated with poor renal prognosis and increased mortality. The impact of intraoperative hemodialysis (IHD) on postoperative renal function remains unknown. We aimed to evaluate the utility of IHD during open-heart surgery in patients with severe non-dialysis-dependent chronic kidney disease (CKD-NDD) and its association with clinical outcomes.

Methods

This was a single-center retrospective cohort study that employed IHD during non-emergency open-heart surgery in patients with CKD stage G4 or G5. Patients who underwent emergent surgery, chronic dialysis, and/or kidney transplantation were excluded. We retrospectively compared the clinical characteristics and outcomes between patients from the IHD and non-IHD groups. The primary outcomes were 90-day mortality and postoperative initiation of renal replacement therapy (RRT).

Results

Twenty-eight patients were categorized into the IHD group and 33 into the non-IHD group. When comparing the IHD and non-IHD groups, men accounted for 60.7 vs. 50.3% of patients, the mean patient age was 74.5 (standard deviation [SD] 7.0) vs. 72.9 (SD 9.4) years (p = 0.744), and the proportion of patients with CKD G4 was 67.9 vs. 84.9% (p = 0.138). Regarding clinical outcomes, no significant differences were observed in the 90-day mortality (7.1 vs. 3.0%; p = 0.482) and 30-day RRT (17.9 vs. 30.3%; p = 0.373) rates between the groups. Among the patients with CKD G4, the IHD group had significantly lower 30-day RRT rates than the non-IHD group (0 vs. 25.0%; p = 0.032). RRT initiation was less likely for patients with CKD G4 (odds ratio 0.07, 95% confidence interval [CI] 0.01–0.37; p = 0.002); however, IHD did not significantly decrease the incidence of poor clinical outcomes (odds ratio 0.20, 95% CI 0.04–1.07; p = 0.061).

Conclusions

IHD during open-heart surgery in patients with CKD-NDD did not improve their clinical outcomes with regards to postoperative dialysis. However, for patients with CKD G4, IHD may be useful for postoperative cardiac management.

Protective effect of sacubitril/valsartan (Entresto) on kidney function and filtration barrier injury in a porcine model of partial nephrectomy

Kidney surgery often includes organ ischaemia with a risk of acute kidney injury. The present study tested if treatment with the combined angiotensin II-angiotensin II receptor type 1 and neprilysin blocker Entresto (LCZ696, sacubitril/valsartan) protects filtration barrier and kidney function after ischaemia and partial nephrectomy (PN) in pigs. Single kidney glomerular filtration rate (GFR) by technetium-99m diethylene-triamine-pentaacetate clearance was validated (n = 6). Next, four groups of pigs were followed for 15 days (n = 24) after PN (one-third right kidney, 60 min ischaemia) + Entresto (49/51 mg/day; n = 8), PN + vehicle (n = 8), sham + Entresto (49/51 mg/day; n = 4) and sham + vehicle (n = 4). GFR, diuresis and urinary albumin were measured at baseline and from each kidney after 15 days. The sum of single-kidney GFR (right 25 ± 6 mL/min, left 31 ± 7 mL/min) accounted for the total GFR (56 ± 14 mL/min). Entresto had no effect on baseline blood pressure, p-creatinine, mid-regional pro-atrial natriuretic peptide (MR-proANP), heart rate and diuresis. After 15 days, Entresto increased GFR in the uninjured kidney (+23 ± 6 mL/min, P < .05) and reduced albuminuria from both kidneys. In the sham group, plasma MR-proANP was not altered by Entresto; it increased to similar levels 2 h after surgery with and without Entresto. Fractional sodium excretion increased with Entresto. Kidney histology and kidney injury molecule-1 in cortex tissue were not different. In conclusion, Entresto protects the filtration barrier and increases the functional adaptive response of the uninjured kidney.

Strategies for post-cardiac surgery acute kidney injury prevention: A network meta-analysis of randomized controlled trials

Objects

Cardiac surgery is associated with acute kidney injury (AKI). However, the effects of various pharmacological and non-pharmacological strategies for AKI prevention have not been thoroughly investigated, and their effectiveness in preventing AKI-related adverse outcomes has not been systematically evaluated.

Methods

Studies from PubMed, Embase, and Medline and registered trials from published through December 2021 that evaluated strategies for preventing post-cardiac surgery AKI were identified. The effectiveness of these strategies was assessed through a network meta-analysis (NMA). The secondary outcomes were prevention of dialysis-requiring AKI, mortality, intensive care unit (ICU) length of stay (LOS), and hospital LOS. The interventions were ranked using the P-score method. Confidence in the results of the NMA was assessed using the Confidence in NMA (CINeMA) framework.

Results

A total of 161 trials (involving 46,619 participants) and 53 strategies were identified. Eight pharmacological strategies {natriuretic peptides [odds ratio (OR): 0.30, 95% confidence interval (CI): 0.19-0.47], nitroprusside [OR: 0.29, 95% CI: 0.12-0.68], fenoldopam [OR: 0.36, 95% CI: 0.17-0.76], tolvaptan [OR: 0.35, 95% CI: 0.14-0.90], N-acetyl cysteine with carvedilol [OR: 0.37, 95% CI: 0.16-0.85], dexmedetomidine [OR: 0.49, 95% CI: 0.32-0.76;], levosimendan [OR: 0.56, 95% CI: 0.37-0.84], and erythropoietin [OR: 0.62, 95% CI: 0.41-0.94]} and one non-pharmacological intervention (remote ischemic preconditioning, OR: 0.76, 95% CI: 0.63-0.92) were associated with a lower incidence of post-cardiac surgery AKI with moderate to low confidence. Among these nine strategies, five (fenoldopam, erythropoietin, natriuretic peptides, levosimendan, and remote ischemic preconditioning) were associated with a shorter ICU LOS, and two (natriuretic peptides [OR: 0.30, 95% CI: 0.15-0.60] and levosimendan [OR: 0.68, 95% CI: 0.49-0.95]) were associated with a lower incidence of dialysis-requiring AKI. Natriuretic peptides were also associated with a lower risk of mortality (OR: 0.50, 95% CI: 0.29-0.86). The results of a sensitivity analysis support the robustness and effectiveness of natriuretic peptides and dexmedetomidine.

Conclusion

Nine potentially effective strategies were identified. Natriuretic peptide therapy was the most effective pharmacological strategy, and remote ischemic preconditioning was the only effective non-pharmacological strategy. Preventive strategies might also help prevent AKI-related adverse outcomes. Additional studies are required to explore the optimal dosages and protocols for potentially effective AKI prevention strategies.

Pleiotropic Roles of Atrial Natriuretic Peptide in Anti-Inflammation and Anti-Cancer Activity

Simple Summary

The relationship between inflammation and carcinogenesis, as well as the response to anti-tumor therapy, is intimate. Atrial natriuretic peptides (ANPs) play a pivotal role in the homeostatic control of blood pressure, electrolytes, and water balance. In addition, ANPs exert immune-modulatory effects in the tissue microenvironment, thus exhibiting a fascinating ability to prevent inflammation-related tumorigenesis and cancer recurrence. In cancers, ANPs show anti-proliferative effects through several molecular pathways. Furthermore, ANPs attenuate the side effects of cancer therapy. Therefore, ANPs have potential therapeutic value in tumors. Here, we summarized the roles of ANPs in diverse aspects of the immune system and the molecular mechanisms underlying the anti-cancer effects of ANPs, contributing to the development of ANP-based anti-cancer agents.

Abstract

The atrial natriuretic peptide (ANP), a cardiovascular hormone, plays a pivotal role in the homeostatic control of blood pressure, electrolytes, and water balance and is approved to treat congestive heart failure. In addition, there is a growing realization that ANPs might be related to immune response and tumor growth. The anti-inflammatory and immune-modulatory effects of ANPs in the tissue microenvironment are mediated through autocrine or paracrine mechanisms, which further suppress tumorigenesis. In cancers, ANPs show anti-proliferative effects through several molecular pathways. Furthermore, ANPs attenuate the side effects of cancer therapy. Therefore, ANPs act on several hallmarks of cancer, such as inflammation, angiogenesis, sustained tumor growth, and metastasis. In this review, we summarized the contributions of ANPs in diverse aspects of the immune system and the molecular mechanisms underlying the anti-cancer effects of ANPs.

Association Between the Presence of Pulmonary Hypertension Before Cardiovascular Surgery and the Nephroprotective Effect of Carperitide: A Retrospective Cohort Study

Introduction

We hypothesized that the nephroprotective and diuretic effects of carperitide are effective in patients with pulmonary hypertension. We examined the presence of preoperative pulmonary hypertension and the effects of carperitide.

Methods

In this retrospective cohort study, we included patients aged 20 years or older who received carperitide during cardiovascular surgery and were admitted to the postoperative intensive care unit. We used hospital data from March 2019 to September 2021. The outcomes were the incidence of acute kidney injury, the number of patients using renal replacement therapy in the intensive care unit, urine volume in the first 24 hours after surgery, and the difference in serum creatinine concentrations between before and after surgery. After adjusting for confounding factors by multivariate analysis, we compared the difference in outcomes with and without preoperative pulmonary hypertension (systolic pulmonary artery pressure ≥36 mmHg).

Results

The study included 244 patients, with 72 (29.5%) in the pulmonary hypertension group and 172 (70.5%) in the control group. Acute kidney injury occurred in eight (11.1%) patients in the pulmonary hypertension group and in 18 (10.5%) patients in the control group, with no significant difference by logistic regression analysis (odds ratio 1.40, 95% confidence interval 0.54-3.62, p=0.49). Additionally, the use of renal replacement therapy, urine volume at 24 hours postoperatively, and the difference in serum creatinine concentrations were not different between the two groups.

Conclusions

Our results suggest that the effect of carperitide during cardiovascular surgery is not affected by the presence or absence of pulmonary hypertension.

Osteocrin, a bone-derived humoral factor, exerts a renoprotective role in ischemia-reperfusion injury in mice

Background

Osteocrin (OSTN), a bone-derived humoral factor, was reported to act on heart and bone by potentiating the natriuretic peptide (NP) system. Ostn gene polymorphisms have been associated with renal function decline, but its pathophysiological role in the kidney remains unclear.

Methods

The role of endogenous OSTN was investigated using systemic Ostn-knockout (KO) mice. As a model for OSTN administration, liver-specific Ostn-overexpressing mice crossed with KO (KO-Tg) were generated. These mice were subjected to unilateral ischemia–reperfusion injury (IRI) and renal lesions after 21 days of insult were evaluated. A comprehensive analysis of the Wnt/β-catenin pathway was performed using a polymerase chain reaction (PCR) array. Reporter plasmid-transfected proximal tubular cells (NRK52E) were used to investigate the mechanism by which OSTN affects the pathway.

Results

After injury, KO mice showed marginal worsening of renal fibrosis compared with wild-type mice, with comparable renal atrophy. KO-Tg mice showed significantly ameliorated renal atrophy, fibrosis and tubular injury, together with reduced expressions of fibrosis- and inflammation-related genes. The PCR array showed that the activation of the Wnt/β-catenin pathway was attenuated in KO-Tg mice. The downstream targets Mmp7, Myc and Axin2 showed similar results. MMP7 and Wnt2 were induced in corticomedullary proximal tubules after injury, but not in KO-Tg. In NRK52E, OSTN significantly potentiated the inhibitory effects of NP on transforming growth factor β1–induced activation of the Wnt/β-catenin pathway, which was reproduced by a cyclic guanosine monophosphate analog.

Conclusions

Ectopic Ostn overexpression ameliorated subsequent renal injury following ischemia–reperfusion. OSTN could represent possible renoprotection in acute to chronic kidney disease transition, thus serving as a potential therapeutic strategy.

Comparative effectiveness of pharmacological interventions to prevent postoperative delirium: a network meta-analysis

Many pharmacologic agents were investigated for the effect to prevent delirium. We aimed to comprehensively compare the effect of the pharmacological interventions to prevent postoperative delirium. A Bayesian network meta-analysis of randomized trials was performed using random effects model. PubMed, the Cochrane Central Register of Controlled Trials, and Embase were searched on 20 January 2021. Randomized trials comparing the effect of a drug to prevent postoperative delirium with another drug or placebo in adult patients undergoing any kind of surgery were included. Primary outcome was the postoperative incidence of delirium. Eighty-six trials with 26,992 participants were included. Dexmedetomidine, haloperidol, and atypical antipsychotics significantly decreased the incidence of delirium than placebo [dexmedetomidine: odds ratio 0.51, 95% credible interval (CrI) 0.40-0.66, moderate quality of evidence (QOE); haloperidol: odds ratio 0.59, 95% CrI 0.37-0.95, moderate QOE; atypical antipsychotics: odds ratio 0.27, 95% CrI 0.14-0.51, moderate QOE]. Dexmedetomidine and atypical antipsychotics had the highest-ranking probabilities to be the best. However, significant heterogeneity regarding diagnostic time window as well as small study effects precludes firm conclusion.

Protective Renal Effects of Atrial Natriuretic Peptide: Where Are We Now?

Atrial natriuretic peptide belongs to the family of natriuretic peptides, a system with natriuretic, diuretic, and vasodilator effects that opposes to renin-angiotensin system. In addition to its classic actions, atrial natriuretic peptide exerts a nephroprotective effect given its antioxidant and anti-inflammatory properties, turning it as a beneficial agent against acute and chronic kidney diseases. This minireview describes the most relevant aspects of atrial natriuretic peptide in the kidney, including its renal synthesis, physiological actions through specific receptors, the importance of its metabolism, and its potential use in different pathological scenarios.

Perioperative Clinical Trials in AKI

To characterize current evidence and current foci of perioperative clinical trials, we systematically reviewed Medline and identified perioperative trials involving 100 or more adult patients undergoing surgery and reporting renal end points that were published in high-impact journals since 2004. We categorized the 101 trials identified based on the nature of the intervention and summarized major trial findings from the five categories most applicable to perioperative management of patients. Trials that targeted ischemia suggested that increasing perioperative renal oxygen delivery with inotropes or blood transfusion does not reliably mitigate acute kidney injury (AKI), although goal-directed therapy with hemodynamic monitors appeared beneficial in some trials. Trials that have targeted inflammation or oxidative stress, including studies of nonsteroidal anti-inflammatory drugs, steroids, N-acetylcysteine, and sodium bicarbonate, have not shown renal benefits, and high-dose perioperative statin treatment increased AKI in some patient groups in two large trials. Balanced crystalloid intravenous fluids appear safer than saline, and crystalloids appear safer than colloids. Liberal compared with restrictive fluid administration reduced AKI in a recent large trial in open abdominal surgery. Remote ischemic preconditioning, although effective in several smaller trials, failed to reduce AKI in two larger trials. The translation of promising preclinical therapies to patients undergoing surgery remains poor, and most interventions that reduced perioperative AKI compared novel surgical management techniques or existing processes of care rather than novel pharmacologic interventions.

Protection of kidney function and tissue integrity by pharmacologic use of natriuretic peptides and neprilysin inhibitors

With variable potencies atrial-, brain-type and c-type natriuretic peptides (NP)s, best documented for ANP and its analogues, promote sodium and water excretion, renal blood flow, lipolysis, lower blood pressure, and suppress renin and aldosterone secretion through interaction predominantly with cGMP-coupled NPR-A receptor. Infusion of especially ANP and its analogues up to 50 ng/kg/min in patients with high risk of acute kidney injury (cardiac vascular bypass surgery, intraabdominal surgery, direct kidney surgery) protects kidney function (GFR, plasma flow, medullary flow, albuminuria, renal replacement therapy, tissue injury) at short term and also long term and likely additively with the diuretic furosemide. This documents a pharmacologic potential for the pathway. Neprilysin (NEP, neutral endopeptidase) degrades NPs, in particular ANP, and angiotensin II. The drug LCZ696, a mixture of the neprilysin inhibitor sacubitril and the ANGII-AT1 receptor blocker valsartan, was FDA approved in 2015 and marketed as Entresto®. In preclinical studies of kidney injury, LCZ696 and NPs lowered plasma creatinine, countered hypoxia and oxidative stress, suppressed proinflammatory cytokines, and inhibited fibrosis. Few randomized clinical studies exist and were designed with primary cardiac outcomes. The studies showed that LCZ696/entresto stabilized and improved glomerular filtration rate in patients with chronic kidney disease. LCZ696 is safe to use concerning kidney function and stabilizes or increases GFR. In perspective, combined AT1 and neprilysin inhibition is a promising approach for long-term renal protection in addition to AT1 receptor blockers in acute kidney injury and chronic kidney disease.

Novel therapeutics for the treatment of hypertension and its associated complications: peptide- and nonpeptide-based strategies

The renin-angiotensin-aldosterone system (RAAS) is responsible for maintaining blood pressure and vascular tone. Modulation of the RAAS, therefore, interferes with essential cellular processes and leads to high blood pressure, oxidative stress, inflammation, fibrosis, and hypertrophy. Consequently, these conditions cause fatal cardiovascular and renal complications. Thus, the primary purpose of hypertension treatment is to diminish or inhibit overactivated RAAS. Currently available RAAS inhibitors have proven effective in reducing blood pressure; however, beyond hypertension, they have failed to treat end-target organ injury. In addition, RAAS inhibitors have some intolerable adverse effects, such as hyperkalemia and hypotension. These gaps in the available treatment for hypertension require further investigation of the development of safe and effective therapies. Current research is focused on the combination of existing and novel treatments that neutralize the angiotensin II type I (AT1) receptor-mediated action of the angiotensin II peptide. Preclinical studies of peptide- and nonpeptide-based therapeutic agents demonstrate their conspicuous impact on the treatment of cardiovascular diseases in animal models. In this review, we will discuss novel therapeutic agents being developed as RAAS inhibitors that show prominent effects in both preclinical and clinical studies. In addition, we will also highlight the need for improvement in the efficacy of existing drugs in the absence of new prominent antihypertensive drugs.

Influence of chronic kidney disease on early clinical outcomes after off-pump coronary artery bypass grafting

Background

Patients with chronic kidney disease (CKD) have a high incidence of coronary heart disease, which is the leading cause of death in these patients. Coronary artery bypass grafting (CABG) significantly increases short-term mortality and decreases long-term mortality in patients with CKD compared with percutaneous coronary intervention (PCI). The effect of CKD on the early outcomes of off-pump CABG is not well-studied. We aimed to investigate the effect of CKD on early postoperative mortality and complications following off-pump CABG.

Methods

We retrospectively analyzed preoperative baseline and surgery data for 1173 patients undergoing off-pump CABG from January 2010 to December 2017 in the Department of Cardiac Surgery, Peking University First Hospital. Outpatient follow-up was performed until 30 days postoperatively. Patients with estimated glomerular filtration rates calculated according to the Chronic Kidney Disease Epidemiology Collaboration equation of ≥60 mL/min/1.73 m² were assigned to the normal renal function group (normal group, n = 924), and those with a rate < 60 mL/min/1.73 m² were assigned to the CKD group (CKD group, n = 249).

Results

Patients in the CKD group were seriously ill with multiple complications, and postoperative 30-day mortality and complication rates were significantly higher than those in the normal group. In the logistic regression analysis, after correcting for common confounding factors, namely sex, age, and left ventricular ejection fraction, preoperative CKD was a risk factor for postoperative acute kidney injury, perioperative myocardial infarction, gastrointestinal bleeding, secondary tracheal intubation, stroke, chest wound infection, prolonged mechanical ventilation (≥ 24 h), prolonged intensive care unit stay (≥ 72 h), prolonged length of stay (≥ 14 d), dialysis requirement, and postoperative death within 30 days.

Conclusions

Patients with CKD had more preoperative complications, and their postoperative 30-day mortality and complication rates after off-pump CABG were significantly higher than those of patients with normal renal function. For CABG patients with CKD, the risk of surgery should be assessed carefully, and comprehensive measures should be taken to strengthen perioperative management, with an aim to reduce complications and mortality and improve surgical outcomes.

Intravenous sildenafil citrate and post-cardiac surgery acute kidney injury: a double-blind, randomised, placebo-controlled trial

BACKGROUND

This study assessed whether i.v. sildenafil citrate prevented acute kidney injury in at-risk patients undergoing cardiac surgery with cardiopulmonary bypass.

METHODS

In a double-blind RCT, adults at increased risk of acute kidney injury undergoing cardiac surgery in a single UK tertiary centre were randomised to receive sildenafil citrate 12.5 mg kg^-1 i.v. over 150 min or dextrose 5% at the commencement of surgery. The primary outcome was serum creatinine measured at six post-randomisation time points. The primary analysis used a linear mixed-effects model adjusted for the stratification variables, baseline estimated glomerular filtration rate, and surgical procedure. Secondary outcomes considered clinical events and potential disease mechanisms. Effect estimates were expressed as mean differences (MDs) or odds ratios with 95% confidence intervals.

RESULTS

The analysis population comprised eligible randomised patients that underwent valve surgery or combined coronary artery bypass graft and valve surgery, with cardiopulmonary bypass, between May 2015 and June 2018. There were 60 subjects in the sildenafil group and 69 in the placebo control group. The difference between groups in creatinine concentration was not statistically significant (MD: 0.88 μmol L^-1 [-5.82, 7.59]). There was a statistically significant increase in multiple organ dysfunction scores in the sildenafil group (MD: 0.54 [0.02, 1.07]; P=0.044). Secondary outcomes, and biomarkers of kidney injury, endothelial function, and inflammatory cell activation, were not significantly different between the groups.

CONCLUSIONS

These results do not support the use of i.v. sildenafil citrate for kidney protection in adult cardiac surgery.

CLINICAL TRIAL REGISTRATION

ISRCTN18386427.

Effect of low-dose atrial natriuretic peptide in critically ill patients with acute kidney injury: a retrospective, single-center study with propensity-score matching

Background

Acute kidney injury (AKI) is a major comorbidity in critically ill patients. Low-dose atrial natriuretic peptide (ANP) has been shown to effectively prevent acute kidney injury (AKI), especially in cardiovascular surgery patients. However, its treatment effects for AKI in critically ill patients are unclear.

Methods

This single-center, retrospective, observational study included patients with AKI diagnosed within 7 days after intensive care unit (ICU) admission during the period January 2010 to December 2017. We conducted a propensity-matched analysis to estimate the treatment effect of low-dose carperitide (a recombinant human ANP) on the clinical outcomes. The primary outcome was a composite of death, renal replacement therapy dependence, or no recovery from AKI (defined as an increase of the serum creatinine level to ≥200% of baseline) at hospital discharge.

Results

During the study period, 4479 adult patients were admitted to the ICU. We identified 1374 eligible patients with AKI diagnosed within 7 days after ICU admission. Among these patients, 346 (25.2%) were treated with low-dose carperitide, with an average dose of 0.019 μg kg^− 1 min^− 1. The primary outcome occurred more often in the treatment group than in the control group (29.7% versus 23.4%, respectively; p = 0.022). After propensity score matching, characteristics of 314 patients from each group were well- balanced. Significant difference of the primary outcome, as seen with the full cohort, was no longer obtained; no benefit of carperitide was detected in the matched cohort (29.0% versus 25.2%; p = 0.281).

Conclusions

Low-dose ANP showed no treatment effect in general critically ill patients who developed AKI.

Renal effects of Sacubitril/Valsartan in heart failure with reduced ejection fraction: a real life 1-year follow-up study

Real-life data confirming the favourable renal outcome in patients with heart failure (HF) treated with Sacubitril/Valsartan, previously found in several trials (RCTs), are still scant. We evaluated the renal effects of Sacubitril/Valsartan in a real-life sample of HF patients. Observational analysis of 54 consecutive outpatients affected by HF with reduced ejection fraction (HFrEF) and clinical indication for Sacubitril/Valsartan. Patients were evaluated at baseline (T0) and after six (T6) and twelve (T12) months after initiating Sacubitril/Valsartan and compared with a group of 30 historical controls. Mean age: 65.5 ± 11.7 years. Older patients: 29 (53.7%). Mean baseline estimated glomerular filtration rate (eGFR): 59.4 ± 19.2 ml/min/1.73 m2. Patients with chronic kidney disease (CKD), defined by an eGFR < 60 ml/min/1.73 m2, were 29 (53.7%). Sacubitril/Valsartan was less titrated in both older patients and patients with CKD. There were no changes in diuretics during follow-up. Systolic blood pressure (BP) decreased during follow-up (p = 0.014), while left ventricular ejection fraction (LVEF) slighly increased (p < 0.001). Renal function improved after 12 months compared to historical controls (p for interaction < 0.001) and a greater benefit was found in subjects aged < 65 years (p for interaction = 0.002) and patients with CKD (p for interaction = 0.009). A statistically (p = 0.009), but not clinically significant increase in serum potassium was also found, regardless of age and CKD. This is the first study focused on the renal effects of Sacubitril/Valsartan in HFrEF patients followed for 12 months in a real-life clinical context. The improved eGFR, despite lower BP, represents an important confirmation outside the peculiar world of RCTs.

Contrast-Induced Acute Kidney Injury: Review and Practical Update

Contrast-induced acute kidney injury (CI-AKI) is an important consideration in patients undergoing cardiac catheterization. There has been a continuous strive to decrease morbidity and improve procedural safety. This review will address the pathophysiology, predictors, and clinical management of CI-AKI with a concise overview of the pathophysiology and a suggested association with left atrial appendage closure. Minimizing contrast administration and intravenous fluid hydration are the cornerstones of an effective preventive strategy. A few adjunctive pharmacotherapies hold promise, but there are no consensus recommendations on prophylactic therapies.

Prevention of Cardiac Surgery-Associated Acute Kidney Injury: A Review of Current Strategies

Acute kidney injury is a common and often severe postoperative complication after cardiac surgery, and is associated with poor short-term and long-term outcomes. Numerous randomized controlled trials have been conducted to investigate various strategies for prevention of cardiac surgery-associated acute kidney injury. Unfortunately, most trials that have been conducted to date have been negative. However, encouraging results have been demonstrated with preoperative administration of corticosteroids, leukocyte filtration, and administration of inhaled nitric oxide intraoperatively, and implementation of a Kidney Disease: Improving Global Outcomes bundle of care approach postoperatively. These findings require validation in large, multicenter trials.

Predictors of responders for low-dose carperitide monotherapy in patients with acute heart failure

Human atrial natriuretic peptide, known as carperitide, is approved for early relief of dyspnea in patients with acute heart failure (AHF). However, the diuretic effect of carperitide is sometimes insufficient for controlling volume overload. We investigated predictors for the carperitide response in patients with AHF. Forty-seven patients (age: 74 ± 10 years; left ventricular ejection fraction: 42.0% ± 15.9%) with AHF were enrolled and treated with carperitide monotherapy at a dose of 0.0125 μg/kg/min. Patients without sufficient diuresis (< 60 ml/h) or improvement of symptoms by 4 h after carperitide administration, despite increasing to twice the dose of carperitide and adding another agent, were defined as non-responders. Twenty-four (51%) patients were defined as responders and treated with low-dose carperitide monotherapy on the first day. Multiple logistic regression analysis showed that the response to carperitide monotherapy was independently predicted by serum creatinine levels and systolic blood pressure (SBP) on admission. The area under the receiver-operating characteristic curve for predicting the response to carperitide by SBP was 0.808 (95% confidence interval [0.686-0.930], sensitivity: 83.3%, specificity: 65.2%, cutoff value: 135 mmHg). Four (8.5%) patients developed asymptomatic transient hypotension. Worsening renal function occurred within 3 days of admission in three (6.4%) patients who received low-dose carperitide therapy. SBP and serum creatinine levels on admission might be useful for predicting the diuretic response to low-dose carperitide monotherapy in patients with AHF. Initial use of low-dose carperitide therapy does not have adverse effects on renal function.

Low-dose atrial natriuretic peptide for prevention or treatment of acute kidney injury: a systematic review and meta-analysis

Background

Theoretically, atrial natriuretic peptide (ANP), especially low-dose ANP, is beneficial in acute kidney injury (AKI). In this study, we examined whether low-dose ANP is effective in preventing or treating AKI by conducting an updated systematic review for randomized controlled trials (RCTs).

Method

We searched the Excerpta Medica database (EMBASE), PubMed, and Cochrane CENTRAL databases for RCTs that compare the effects of low-dose ANP (≤ 50 ng/kg/min) with a placebo or conventional therapy in at-risk patients or patients with AKI. The primary outcome was the incidence of new AKI (in prevention RCTs), while the secondary outcomes were in-hospital mortality rate, renal replacement therapy (RRT) requirement, length of hospital and intensive care unit (ICU) stay, incidence of hypotension, and peak serum creatinine levels. The risk-of-bias was evaluated using the Cochrane Collaboration risk-of-bias tool. Trial sequential analysis (TSA) was used for each outcome of interest.

Results

A total of 18 RCTs (16 prevention and two treatment trials) fulfilled our inclusion criteria. In prevention RCTs, the incidence of new AKI was significantly low in the low-dose ANP group (relative risk [RR] = 0.51; 95% confidence interval [CI] = 0.36–0.72; P = 0.0001) compared to the control group. In addition, the low-dose ANP group showed a significantly reduced RRT requirement in both prevention (RR = 0.17; 95% CI = 0.04–0.64; P = 0.009) and treatment (RR = 0.43; 95% CI = 0.20–0.93; P = 0.03) RCTs. Among secondary outcomes, in some cases, low-dose ANP was associated with a reduction in ICU and in-hospital stay. The risk-of-bias assessment and TSA results indicated that the sample sizes and qualities of the RCTs were insufficient to conclude the efficacy of low-dose ANP.

Conclusion

Low-dose ANP might be effective in preventing or treating AKI. However, the evidence accumulated so far is not strong enough to demonstrate ANP’s beneficial effects. The next step is to elucidate the effects of low-dose ANP by conducting multicenter, high-quality, large-sample RCTs.

Trial registration

PROSPERO registry CRD42017068568. Registered 20 June 2017.

Electronic supplementary material

The online version of this article (10.1186/s13054-019-2330-z) contains supplementary material, which is available to authorized users.

Guanylyl Cyclase A in Both Renal Proximal Tubular and Vascular Endothelial Cells Protects the Kidney against Acute Injury in Rodent Experimental Endotoxemia Models

WHAT WE ALREADY KNOW ABOUT THIS TOPIC

WHAT THIS ARTICLE TELLS US THAT IS NEW: BACKGROUND:: Natriuretic peptides are used, based on empirical observations, in intensive care units as antioliguric treatments. We hypothesized that natriuretic peptides prevent lipopolysaccharide-induced oliguria by activating guanylyl cyclase A, a receptor for natriuretic peptides, in proximal tubules and endothelial cells.

METHODS

Normal Sprague-Dawley rats and mice lacking guanylyl cyclase A in either endothelial cells or proximal tubular cells were challenged with lipopolysaccharide and assessed for oliguria and intratubular flow rate by intravital imaging with multiphoton microscopy.

RESULTS

Recombinant atrial natriuretic peptide efficiently improved urine volume without changing blood pressure after lipopolysaccharide challenge in rats (urine volume at 4 h, lipopolysaccharide: 0.6 ± 0.3 ml · kg · h; lipopolysaccharide + fluid resuscitation: 4.6 ± 2.0 ml · kg · h; lipopolysaccharide + fluid resuscitation + atrial natriuretic peptide: 9.0 ± 4.8 ml · kg · h; mean ± SD; n = 5 per group). Lipopolysaccharide decreased glomerular filtration rate and slowed intraproximal tubular flow rate, as measured by in vivo imaging. Fluid resuscitation restored glomerular filtration rate but not tubular flow rate. Adding atrial natriuretic peptide to fluid resuscitation improved both glomerular filtration rate and tubular flow rate. Mice lacking guanylyl cyclase A in either proximal tubules or endothelium demonstrated less improvement of tubular flow rate when treated with atrial natriuretic peptide, compared with control mice. Deletion of endothelial, but not proximal tubular, guanylyl cyclase A augmented the reduction of glomerular filtration rate by lipopolysaccharide.

CONCLUSIONS

Both endogenous and exogenous natriuretic peptides prevent lipopolysaccharide-induced oliguria by activating guanylyl cyclase A in proximal tubules and endothelial cells.

Human atrial natriuretic peptide for acute kidney injury in adult critically ill patients: A multicenter prospective observational study

PURPOSE

Acute kidney injury (AKI) is common in the intensive care unit (ICU). Selected clinical studies have implied human atrial natriuretic peptide (hANP) improves renal function; however, the treatment effects for AKI are unclear.

METHODS

A multicenter prospective observational study in 13 Japanese ICUs. The effects of hANP were estimated by the standardized mortality ratio weighted analyses of generalized linear models using propensity scores. The primary outcome was renal replacement therapy (RRT) or death in the ICU.

RESULTS

Of 904 patients with AKI, 63 received hANP as a treatment for AKI. The primary outcome occurred in 20.5% (185/904). HANP did not reduce the risk of RRT or death in the ICU (risk ratio 1.12, 95% confidence interval [CI] 0.74 to 1.69) and was associated with a lower mean arterial pressure (β -3.8 mmHg, 95%CI -7.6 to -0.1), a longer hospital length of stay (β 12.0 days, 95%CI 1.2 to 22.8) and a lower eGFR at hospital discharge (β -10.4 mL/min/m², 95%CI -19.1 to -1.7). No beneficial effect was observed in subgroups of cardiovascular surgery, sepsis, nor chronic kidney disease.

CONCLUSIONS

In critically ill patients with AKI, the treatment effect of hANP was not evident on dialysis-free survival in the ICU.

The Japanese clinical practice guideline for acute kidney injury 2016

Acute kidney injury (AKI) is a syndrome which has a broad range of etiologic factors depending on different clinical settings. Because AKI has significant impacts on prognosis in any clinical settings, early detection and intervention is necessary to improve the outcomes of AKI patients. This clinical guideline for AKI was developed by a multidisciplinary approach with nephrology, intensive care medicine, blood purification, and pediatrics. Of note, clinical practice for AKI management which was widely performed in Japan was also evaluated with comprehensive literature search.

The Japanese Clinical Practice Guideline for acute kidney injury 2016

Acute kidney injury (AKI) is a syndrome which has a broad range of etiologic factors depending on different clinical settings. Because AKI has significant impacts on prognosis in any clinical settings, early detection and intervention are necessary to improve the outcomes of AKI patients. This clinical guideline for AKI was developed by a multidisciplinary approach with nephrology, intensive care medicine, blood purification, and pediatrics. Of note, clinical practice for AKI management which was widely performed in Japan was also evaluated with comprehensive literature search.

Particulate Guanylyl Cyclase A/cGMP Signaling Pathway in the Kidney: Physiologic and Therapeutic Indications

The particulate guanylyl cyclase A (pGC-A)/cGMP pathway plays important roles in regulating renal physiological function and as well as in counteracting pathophysiological conditions. Naturally occurring peptide pGC-A activators consist of atrial natriuretic peptide (ANP), b-type NP (BNP), and urodilatin (URO). These activators bind and activate pGC-A, generating the second messenger cyclic 3′,5′ guanosine monophosphate (cGMP). Cyclic GMP binds to downstream pathway effector molecules including protein kinase G (PKG), cGMP-gated ion channels, and phosphodiesterases (PDEs). These mediators result in a variety of physiological actions in the kidney, including diuresis, natriuresis, increased glomerular filtration rate (GFR) and organ protection, thus, opposing renal cellular injury and remodeling. Downstream proteins regulated by PKG include collagen 1 (Col-1), transforming growth factor beta (TGF-β) and apoptosis-related proteins. In addition to their physiological regulatory effects, pGC-A/cGMP signaling is critical for preserving renal homeostasis in different renal diseases such as acute kidney injury (AKI). Regarding therapeutic options, native pGC-A activators have short half-lives and their activity can be further enhanced by advances in innovative peptide engineering. Thus, novel designer peptide pGC-A activators with enhanced renal activity are under development.

Comparative Efficacy of Drugs for Preventing Acute Kidney Injury after Cardiac Surgery: A Network Meta-Analysis

BACKGROUND

Acute kidney injury (AKI) occurs frequently after cardiac surgery and has been associated with increased hospital length of stay, mortality, and costs.

OBJECTIVE

We aimed to evaluate the efficacy of pharmacologic strategies for preventing AKI after cardiac surgery.

METHODS

We searched PubMed, Embase, the Cochrane Central Register of Controlled Trials (CENTRAL) up to 6 May 2017 and the reference lists of relevant articles about trials. The outcome was the occurrence of AKI. This is the first network meta-analysis of the different prevention strategies using Bayesian methodology.

RESULTS

The study included 63 articles with 19,520 participants and evaluated the effect of ten pharmacologic strategies to prevent AKI in patients undergoing cardiac surgery. Compared with placebo, the odds ratio (OR) for the occurrence of AKI was 0.24 [95% confidence interval (CI) 0.16-0.34] with natriuretic peptide, 0.33 (95% CI 0.14-0.70) with fenoldopam, 0.54 (95% CI 0.31-0.84) with dexmedetomidine, 0.56 (95% CI 0.29-0.95) with low-dose erythropoietin, 0.63 (95% CI 0.43-0.88) with levosimendan, 0.76 (95% CI 0.52-1.10) with steroids, 0.83 (95% CI 0.48-1.40) with high-dose erythropoietin, 0.85 (95% CI 0.64-1.14) with N-acetylcysteine, 0.96 (95% CI 0.69-1.29) with sodium bicarbonate, and 1.05 (95% CI 0.70-1.41) with statins. The surface under the cumulative ranking curve probabilities indicated that natriuretic peptide was the best treatment therapy and that fenoldopam ranked second.

CONCLUSIONS

Natriuretic peptide is probably the preferred pharmacologic strategy to prevent AKI in adult patients undergoing cardiac surgery, especially in those at high risk of AKI.

CRRL269: a novel designer and renal-enhancing pGC-A peptide activator

The natriuretic peptides (NPs) B-type NP (BNP) and urodilatin (URO) exert renal protective properties via the particulate guanylyl cyclase A receptor (pGC-A). As a potential renal-enhancing strategy, we engineered a novel designer peptide that we call CRRL269. CRRL269 was investigated in human cell lines and in normal canines to define potential cardiorenal enhancing actions. The mechanism of its cardiorenal selective properties was also investigated. In vitro NP receptor activity was quantified with guanosine 3',5'-cyclic monophosphate generation. In vivo effects were determined in normal canine acute infusion studies. We observed that CRRL269 demonstrated enhanced pGC-A activity in renal compared with nonrenal cell lines. CRRL269 exerted enhanced resistance to neprilysin compared with URO. Importantly, CRRL269 exhibited significant and greater increases in urinary sodium excretion and diuresis, with less blood pressure reduction, than BNP or URO in normal canines. CRRL269 retained potent renin-angiotensin-aldosterone system (RAAS) suppressing properties shared by URO and BNP. Also, CRRL269 exerted less arterial relaxation and higher cAMP cardiomyocytes generation than BNP. CRRL269 possessed superior renal and pGC-A activating properties compared with BNP or URO in vitro. CRRL269 exerted enhanced renal actions while suppressing RAAS in vivo and with less hypotension compared with URO or BNP. Together, our study suggests that CRRL269 is a promising innovative renal-enhancing drug, with favorable protective actions targeting cardiorenal disease states through the pGC-A receptor.

Effect of Prophylactic Dialysis on Morbidity and Mortality in Non-Dialysis-Dependent Patients after Coronary Artery Bypass Grafting: A Pilot Study

BACKGROUND/AIMS

Coronary artery bypass grafting (CABG) is associated with an increased risk of morbidity and mortality in patients with pre-existing renal dysfunction. Numerous measures have been implemented to overcome this problem; however, no improvement in outcomes has been achieved. This study was aimed at investigating the effects of prophylactic dialysis on mortality and morbidity in these patients.

METHODS

This randomized-controlled clinical trial enrolled 88 non-dialysis-dependent patients with chronic kidney disease awaiting CABG surgery. Thirty-nine randomly selected patients received dialysis 3 times prior to surgery, and 49 patients formed the control group. Kaplan-Meier analysis and Cox proportional-hazards models were used to identify factors associated with survival.

RESULTS

There was no significant difference in the development of morbidities between the groups (p = 0.413). A significant difference was evident in the average survival time (p = 0.037). Cox proportional-hazards models determined that the hazard ratio of death after surgery was 10.854-fold greater in non-dialysis patients than in patients who received dialysis (hazard ratio = 2).

CONCLUSION

Prophylactic dialysis prior to CABG decreases mortality, but does not affect morbidity, in patients with renal insufficiency.

Effects of low-dose atrial natriuretic peptide infusion on cardiac surgery-associated acute kidney injury: A multicenter randomized controlled trial

PURPOSE

To evaluate the effects of atrial natriuretic peptide (ANP) on renal function and medical costs in patients with acute kidney injury (AKI) associated with cardiac surgery.

MATERIALS AND METHODS

The Japanese trial for AKI in Post-cardiovascular surgery patients by ANP (JAPAN) was a prospective, multicenter, randomized, double-blind, placebo-controlled study conducted in 11 hospitals in Japan. Acute kidney injury was defined as an increase in serum creatinine of at least 0.3 mg/dL within 48 hours. The patients were randomly assigned to receive ANP (0.02 μg kg^-1 min^-1) or placebo. The primary end point was a change in renal function. The secondary end points were a need for renal replacement therapy, the lengths of intensive care unit and hospital stays, and medical costs incurred over the 90-day follow-up.

RESULTS

Of the 77 randomized patients, 37 were in the ANP group and 40 were in the placebo group. Although ANP significantly (P = .018) increased urine output, it did not significantly improve renal function compared with placebo. There were no significant differences between the groups in the renal replacement therapy rate, the lengths of the intensive care unit and hospital stays, or medical costs.

CONCLUSION

Atrial natriuretic peptide infusion did not show a renoprotective effect or cost-saving effect in the treatment of cardiac surgery-associated AKI.

Renin-Angiotensin System Control for Chronic Kidney Disease Patients Undergoing Coronary Surgery

PURPOSE

We investigated the effectiveness of active renin-angiotensin-aldosterone system (RAAS) control with human atrial natriuretic peptide (hANP) and an angiotensin II receptor blocker (ARB) in patients with chronic kidney disease (CKD) undergoing coronary artery bypass grafting (CABG).

METHODS

A total of 286 consecutive patients with CKD undergoing CABG were divided into three groups: Group C (n = 50) receiving placebo, the hANP group (n = 60) receiving hANP, and the active RAAS control therapy (ARC) group (n = 56) receiving hANP plus an ARB. Renal function, brain natriuretic peptide (BNP) and RAAS parameters were analyzed.

RESULTS

After 1 year, renal function parameters were better in the hANP and ARC groups compared with group C, and the dialysis rate was significantly lower (group C: 12%, hANP group: 1.7%, ARC group: 1.8%, p = 0.018) in the hANP and ARC groups. BNP levels were significantly lower in the hANP and ARC groups compared with group C (p = 0.001). There was also a significant difference of aldosterone among the groups (p = 0.023), as well as a significant difference between group C and the ARC group (p = 0.017).

CONCLUSIONS

The present study showed that active RAAS control preserved renal function in patients with CKD undergoing CABG. The improved early postoperative outcome with RAAS control may lead to long-term inhibition of cardiovascular events.

Efficacy of Carperitide in Hemodialysis Patients Undergoing Cardiac Surgery

PURPOSE

Recently, performance of cardiac surgery in hemodialysis patients has increased, but the mortality rate is high.

METHODS

We retrospectively examined the early and long-term outcomes in 128 dialysis patients who underwent cardiac surgery with or without carperitide infusion and were followed for 2 years. Sixty-three patients received carperitide infusion during surgery and 65 patients did not.

RESULTS

The hospital mortality rate was 1.6% in the carperitide group and 12.3% in the non-carperitide group, being significantly lower in the carperitide group. The 2-year actuarial survival rate was 90.5% ± 3.7% in the carperitide group, and 76.9% ± 5.2% in the non-carperitide group, while the major adverse cardiovascular and cerebrovascular events (MACCE)-free rate at 2 years postoperatively was 90.5% ± 3.7% in the carperitide group and 67.7% ± 5.8% in the non-carperitide group.

CONCLUSIONS

These findings suggest that carperitide improves the early postoperative outcome in dialysis patients undergoing cardiac surgery, as has already been demonstrated in non-dialysis patients. An early postoperative cardioprotective effect of carperitide and improvement of renal function in oliguric patients might have contributed to this outcome. However, this was a retrospective study, so a prospective investigation is required to demonstrate the mechanisms involved. In addition, further evaluation of the long-term results would be desirable.

Heart failure epidemiology and novel treatments in Japan: facts and numbers

Japan has the highest proportion of older people in the world, 25.9% of the population were aged 65 or above in 2014. Although there have been no population‐based studies that precisely examined the prevalence of heart failure in Japan, one report estimated the number of Japanese outpatients with left ventricular dysfunction was 979, 000 (0.8% of total population), which was projected to increase gradually as the population ages, reaching 1.3 million by 2030. Ischemic etiology was less frequently observed in Japan (31–47%) than in western population (54–57%). The prevalence of HF with preserved ejection fraction was similar between Japan (34–68%) and western countries (34–51%). Non‐cardiac co‐morbidities such as chronic obstructive pulmonary diseases and anemia were observed in 6–9% in Japan and 19–31% in western countries, and 35–58% in Japan and 37–56% in western countries, respectively. The definition of chronic kidney disease widely differed among studies. A relatively good survival prognosis in Japanese patients has been discussed. One‐year mortality after discharge from initial hospitalization was 9–12%, which seems to be better than the western cohort. Although length of stay was remarkably longer in Japan (15–21 days) than western countries (4–9 days), it will have to be shortened, as Japan is now being faced with an upcoming HF pandemic. Some treatments in Japan are not approved outside Japan. Such treatments include carperitide infusion (used in 58% of hospitalized HF), nicorandil infusion (9.6%), and oral pimobendan (5%). More recently, landiolol and tolvaptan have been approved. Although these drugs might have a potential to be an effective therapeutic option, lack of corroborating evidence in many of such treatments would emphasize the need for larger clinical trials.

Evaluation of Short-Term Changes in Serum Creatinine Level as a Meaningful End Point in Randomized Clinical Trials

Observational studies have shown that acute change in kidney function (specifically, AKI) is a strong risk factor for poor outcomes. Thus, the outcome of acute change in serum creatinine level, regardless of underlying biology or etiology, is frequently used in clinical trials as both efficacy and safety end points. We performed a meta-analysis of clinical trials to quantify the relationship between positive or negative short-term effects of interventions on change in serum creatinine level and more meaningful clinical outcomes. After a thorough literature search, we included 14 randomized trials of interventions that altered risk for an acute increase in serum creatinine level and had reported between-group differences in CKD and/or mortality rate ≥3 months after randomization. Seven trials assessed interventions that, compared with placebo, increased risk of acute elevation in serum creatinine level (pooled relative risk, 1.52; 95% confidence interval, 1.22 to 1.89), and seven trials assessed interventions that, compared with placebo, reduced risk of acute elevation in serum creatinine level (pooled relative risk, 0.57; 95% confidence interval, 0.44 to 0.74). However, pooled risks for CKD and mortality associated with interventions did not differ from those with placebo in either group. In conclusion, several interventions that affect risk of acute, mild to moderate, often temporary elevation in serum creatinine level in placebo-controlled randomized trials showed no appreciable effect on CKD or mortality months later, raising questions about the value of using small to moderate changes in serum creatinine level as end points in clinical trials.

Natriuretic Peptide Receptor Guanylyl Cyclase-A in Podocytes is Renoprotective but Dispensable for Physiologic Renal Function

The cardiac natriuretic peptides (NPs), atrial NP and B-type NP, regulate fluid homeostasis and arterial BP through renal actions involving increased GFR and vascular and tubular effects. Guanylyl cyclase-A (GC-A), the transmembrane cGMP-producing receptor shared by these peptides, is expressed in different renal cell types, including podocytes, where its function is unclear. To study the effects of NPs on podocytes, we generated mice with a podocyte-specific knockout of GC-A (Podo-GC-A KO). Despite the marked reduction of GC-A mRNA in GC-A KO podocytes to 1% of the control level, Podo-GC-A KO mice and control littermates did not differ in BP, GFR, or natriuresis under baseline conditions. Moreover, infusion of synthetic NPs similarly increased the GFR and renal perfusion in both genotypes. Administration of the mineralocorticoid deoxycorticosterone-acetate (DOCA) in combination with high salt intake induced arterial hypertension of similar magnitude in Podo-GC-A KO mice and controls. However, only Podo-GC-A KO mice developed massive albuminuria (controls: 35-fold; KO: 5400-fold versus baseline), hypoalbuminemia, reduced GFR, and marked glomerular damage. Furthermore, DOCA treatment led to decreased expression of the slit diaphragm-associated proteins podocin, nephrin, and synaptopodin and to enhanced transient receptor potential canonical 6 (TRPC6) channel expression and ATP-induced calcium influx in podocytes of Podo-GC-A KO mice. Concomitant treatment of Podo-GC-A KO mice with the TRPC channel blocker SKF96365 markedly ameliorated albuminuria and glomerular damage in response to DOCA. In conclusion, the physiologic effects of NPs on GFR and natriuresis do not involve podocytes. However, NP/GC-A/cGMP signaling protects podocyte integrity under pathologic conditions, most likely by suppression of TRPC channels.

Plasma levels of natriuretic peptides and development of chronic kidney disease

Background

Plasma levels of atrial and brain natriuretic peptides (ANP and BNP) are increased in patients with chronic kidney disease (CKD) complicated with deteriorated kidney function, but the relationship between the plasma level of ANP or BNP and the future development of CKD is unclear.

Methods

We measured the plasma ANP and BNP levels of 294 local residents without CKD in a Japanese community (56.5 ± 10.4 years, mean ± S.D.), who were followed up for the development of CKD over the next 7 years.

Results

Sixty-three residents developed CKD during the follow-up period, and the baseline level of plasma ANP of these residents was significantly higher than in those without CKD development. Kaplan-Meier analysis showed that the residents with higher ANP than the median value developed CKD more frequently than those with lower ANP. The association between plasma ANP level and CKD development was found to be independent of baseline estimated glomerular filtration rate by a Cox proportional hazards model, while this association became insignificant when adjusted by age; plasma ANP was significantly correlated with age. Compared with ANP, the relationship between plasma BNP and CKD development was unclear in these analyses.

Conclusions

Age-related elevation of plasma ANP levels preceded the development of CKD in the general population of Japan, raising a possibility for ANP being involved in the development of CKD.