Expression of brain natriuretic peptide gene in human heart. Production in the ventricle

Heart failure with preserved ejection fraction in haemodialysis patients: prevalence, diagnosis, risk factors, prognosis

AIMS

Heart failure (HF) is a common complication and the leading cause of mortality in maintenance haemodialysis (MHD) patients. Few studies have investigated heart failure with preserved ejection fraction (HFpEF), which is known to affect a majority of patients. The objective of this study is to explore the prevalence, clinical profiles, diagnosis, risk factors and prognosis of MHD patients with HFpEF.

METHODS AND RESULTS

Four hundred thirty-nine patients haemodialyzsed for over 3 months were enrolled in the study and evaluated for HF according to the European Society of Cardiology guidelines. Clinical and laboratory parameters were recorded at baseline. The median follow-up of the study was 22.5 months. A total of 111 (25.3%) MHD patients were diagnosed with HF, while 94 (84.7%) of the HF patients were classified into HFpEF. The cut-off value of N-terminal pro-B-type natriuretic peptide (NT-proBNP) was 4922.5 pg/mL for predicting HFpEF (sensitivity 0.840, specificity 0.723, AUC 0.866) in MHD patients. Age, diabetes mellitus, coronary artery disease and serum phosphorus were independent risk factors for the incidence of HFpEF in MHD patients while normal urine volume, haemoglobin, serum iron and serum sodium were protective factors. MHD patients with HFpEF had a higher risk of all-cause mortality than those without HF (hazard ratio 2.47, 95% confidence interval 1.55-3.91, P < 0.0001).

CONCLUSIONS

The majority of MHD patients with HF were categorized into HFpEF, with a poor long-term survival rate. NT-proBNP beyond 4922.5 pg/mL performed well in the prediction of HFpEF in MHD patients.

New paradigm shift in the pharmacotherapy for heart failure-where are we now and where are we heading?

Over the past 30 years, accumulating evidence has shown that three main therapies including angiotensin-converting enzyme inhibitors or angiotensin II receptor blockers, ß-blockers, and mineralocorticoid receptor antagonists are the standard treatment for patients with heart failure (HF) who exhibit reduced ejection fraction (EF). However, lessons learned from recent large-scale clinical trials have added a paradigm shift including angiotensin receptor-neprilysin inhibitor, sodium glucose co-transporter 2 inhibitor, and ivabradine. In addition, soluble guanyl cyclase stimulator and omecamtiv mecarbil are also suggested as next generation therapeutic measures for these patients. From these clinical trials, we learned some patients with preserved EF will benefit from certain agents, which has been one of the largest unmet needs over these decades. This article will review these paradigm shifts over the past 10 years and address a new therapeutic algorithm for patients with HF.

Cardiovascular Biomarkers: Lessons of the Past and Prospects for the Future

Cardiovascular diseases (CVDs) are a major healthcare burden on the population worldwide. Early detection of this disease is important in prevention and treatment to minimise morbidity and mortality. Biomarkers are a critical tool to either diagnose, screen, or provide prognostic information for pathological conditions. This review discusses the historical cardiac biomarkers used to detect these conditions, discussing their application and their limitations. Identification of new biomarkers have since replaced these and are now in use in routine clinical practice, but still do not detect all disease. Future cardiac biomarkers are showing promise in early studies, but further studies are required to show their value in improving detection of CVD above the current biomarkers. Additionally, the analytical platforms that would allow them to be adopted in healthcare are yet to be established. There is also the need to identify whether these biomarkers can be used for diagnostic, prognostic, or screening purposes, which will impact their implementation in routine clinical practice.

The effect of subclinical thyroid dysfunction on B- type natriuretic peptide level

Thyroid hormones (THs) have a significant effect on the cardiovascular system. THs increase myocardium stretch, leading to the release of B-type Natriuretic Peptide (BNP), which is considered a diagnostic biomarker of heart failure (HF). Thyroid dysfunctions (subclinical hypothyroidism; SCH and subclinical hyperthyroidism; SCHyper) stimulate several changes in the heart by causing either diastolic or systolic left ventricular dysfunctions leading to HF. This study aims to measure the changes of B- type NP levels in cases of subclinical hypo and hyperthyroidism. The present study aims to measure the changes in B-type Natriuretic Peptide (BNP) levels in subclinical hypo and hyperthyroidism (SCH and SCHyper). A theoretical study was also conducted using a docking program to find the effectiveness of some drugs in inhibiting or promoting B-type Natriuretic Peptide (BNP). A case study was conducted in a private clinic, Mosul- Iraq, from (April 1st – Sep 1) 2021, with 25 healthy participants with normal functioning thyroids as a control group (EU). A newly diagnosed 25 SCH and 17 SCHyper patients participated in this study, considering that none of them have thyroid dysfunctions taking medicine, hypertension, heart diseases, renal failure, and pregnant women. They all were checked for Thyroid Function Tests (TFTs), Free Triiodothyronine (FT3), Free Thyroxin (FT4) and Thyroid Stimulating Hormone (TSH). The plasma level of BNP was measured in all participants of the three groups. The results showed that the plasma level of BNP was higher in SCHyper patients (10.97 pg/ml) as compared to that of SCH patients (8.09 pg/ml) and EU subjects (8.27 pg/ml). Hereby, we could state that subclinical hyperthyroidism, SCHyper, triggers BNP release. Therefore, it should be kept in mind that any high BNP levels due to SCHyper should be considered a reliable diagnostic biomarker of heart failure (HF). Keywords. Thyroid hormone(TH), Subclinical hypothyroidism(SCH), Subclinical hyperthyroidism(SCHyper), Chronic heart disease(CHD), Heart failure(HF), B-type natriuretic peptide(BNP), Docking Study.

Nicotinamide riboside kinase-2 inhibits JNK pathway and limits dilated cardiomyopathy in mice with chronic pressure overload

Nicotinamide riboside kinase-2 (NRK-2) has recently emerged as a critical regulator of cardiac remodeling however, underlying molecular mechanisms is largely unknown. To explore the same, NRK2 knockout (KO) and littermate control mice were subjected to trans-aortic constriction (TAC) or sham surgeries and cardiac function was assessed by serial M-mode echocardiography. A mild cardiac contractile dysfunction was observed in the KOs at the early adaptive phase of remodeling followed by a significant deterioration during the maladaptive cardiac remodeling phase. Consistently, NRK2 KO hearts displayed increased cardiac hypertrophy and heart failure reflected by morphometric parameters as well as increased fetal genes ANP and BNP expressions. Histological assessment revealed an extensive left ventricular (LV) chamber dilatation accompanied by elevated cardiomyopathy and fibrosis in the KO hearts post-TAC. In a gain-of-function model, NRK-2 overexpressing in AC16 cardiomyocytes displayed significantly attenuated fetal genes ANP and BNP expression. Consistently, NRK-2 overexpression attenuated angiotensin II- induced cardiomyocyte death. Mechanistically, we identified NRK-2 as a regulator of JNK MAP kinase and mitochondrial function where NRK-2 overexpression in human cardiomyocytes markedly suppressed the angiotensin II- induced JNK activation and mitochondrial depolarization. Thus, our results demonstrate that NRK-2 plays protective roles in pressure overload- induced dilatative cardiac remodeling and, genetic ablation exacerbates dilated cardiomyopathy, interstitial collagen deposition, and cardiac dysfunction post-TAC due, in part, to increased JNK activation and mitochondrial dysfunction.

Atrioventricular and Ventricular Functional Interdependence in Individuals Without Overt Cardiac Disease

Background

Left atrial (LA) and right ventricular (RV) performance play an integral role in the pathophysiology and prognosis of heart failure. We hypothesized that subclinical left ventricular dysfunction adversely affects LA/RV geometry and function even in a preclinical setting. This study aimed to investigate the atrioventricular and ventricular functional interdependence in a community‐based cohort without overt cardiovascular disease.

Methods and Results

Left ventricular global longitudinal strain (LVGLS), RV free‐wall longitudinal strain and LA phasic strain were assessed by speckle‐tracking echocardiography in 1080 participants (600 men; 62±12 years) between 2014 and 2018. One hundred and forty‐three participants (13.2%) had an abnormal LVGLS (>−18.6%). LA reservoir strain, conduit strain, and RV free‐wall longitudinal strain were significantly decreased in abnormal LVGLS group compared with normal LVGLS group (all P<0.001). LA and RV dysfunction (LA reservoir strain<31.4% and RVLS>−19.2%) were present in 18.9% and 19.6% of participants with abnormal LVGLS. Decreased LVGLS was associated with worse LA reservoir strain, conduit strain and RV free‐wall longitudinal strain (standardized β=−0.20, −0.19 and 0.11 respectively, all P<0.01) independent of cardiovascular risk factors. LA and/or RV dysfunction concomitant with abnormal LVGLS carried significantly increased risk of elevated B‐type natriuretic peptide levels (>28.6 pg/mL for men and >44.4 pg/mL for women) compared with normal LVGLS (odds ratio, 2.01; P=0.030).

Conclusions

LA/RV dysfunction was present in 20% individuals with abnormal LVGLS and multi‐chamber impairment was associated with elevated B‐type natriuretic peptide level, which may provide valuable insights for a better understanding of atrioventricular and ventricular interdependence and possibly heart failure preventive strategies.

The Sick Adipose Tissue: New Insights Into Defective Signaling and Crosstalk With the Myocardium

Adipose tissue (AT) biology is linked to cardiovascular health since obesity is associated with cardiovascular disease (CVD) and positively correlated with excessive visceral fat accumulation. AT signaling to myocardial cells through soluble factors known as adipokines, cardiokines, branched-chain amino acids and small molecules like microRNAs, undoubtedly influence myocardial cells and AT function via the endocrine-paracrine mechanisms of action. Unfortunately, abnormal total and visceral adiposity can alter this harmonious signaling network, resulting in tissue hypoxia and monocyte/macrophage adipose infiltration occurring alongside expanded intra-abdominal and epicardial fat depots seen in the human obese phenotype. These processes promote an abnormal adipocyte proteomic reprogramming, whereby these cells become a source of abnormal signals, affecting vascular and myocardial tissues, leading to meta-inflammation, atrial fibrillation, coronary artery disease, heart hypertrophy, heart failure and myocardial infarction. This review first discusses the pathophysiology and consequences of adipose tissue expansion, particularly their association with meta-inflammation and microbiota dysbiosis. We also explore the precise mechanisms involved in metabolic reprogramming in AT that represent plausible causative factors for CVD. Finally, we clarify how lifestyle changes could promote improvement in myocardiocyte function in the context of changes in AT proteomics and a better gut microbiome profile to develop effective, non-pharmacologic approaches to CVD.

Metabolic Crosstalk between the Heart and Fat

It is now recognized that the heart can behave as a true endocrine organ, which can modulate the function of other tissues. Emerging evidence has shown that visceral fat is one such distant organ the heart communicates with. In fact, it appears that bi-directional crosstalk between adipose tissue and the myocardium is crucial to maintenance of normal function in both organs. In particular, factors secreted from the heart are now known to influence the metabolic activity of adipose tissue and other organs, as well as modulate the release of metabolic substrates and signaling molecules from the periphery. This review summarizes current knowledge regarding primary cardiokines and adipokines involved in heart-fat crosstalk, as well as implications of their dysregulation for cardiovascular health.

Spatiotemporal expression patterns of natriuretic peptides in rat testis and epididymis during postnatal development

Natriuretic peptide (NP) family is composed of atrial, brain and C-type NP (NPPA, NPPB and NPPC). Here, we aimed to investigate NP expression in testis and epididymis during postnatal development. NPPA expression was observed in gonocytes at prepubertal period but in only spermatocytes in pachytene and leptotene/zygotene stage at pubertal period. In prepubertal and pubertal periods, we detected NPPB expression in only Leydig cells. However, NPPC expression was detected in all of the gonocytes and Sertoli cells, spermatocytes and some interstitial cells in prepubertal and pubertal periods. In postpubertal and mature periods, NPPA and NPPB staining were detected in Leydig cells, elongated and round spermatids but not in spermatogonia and spermatocytes. However, we observed NPPC expression in all cells of the seminiferous tubules and Leydig cells in the postpubertal and mature periods. Epididymal epithelium showed intense NPPC expression during postnatal period but weak NPPA and NPPB expression in prepubertal and pubertal periods. The expression of three NPs in the testis significantly increased after puberty. In conclusion, puberty had a significant effect on NP expression in testis. Unlike NPPA and NPPB, expression of NPPC in all cells of the seminiferous tubule suggests that NPPC is effective in each step of spermatogenesis.

Markers of maternal cardiac dysfunction in pre-eclampsia and superimposed pre-eclampsia

AUTHORS

Frances Conti-Ramsden MBBS Academic Clinical Fellow¹, Carolyn Gill PhD BRC Research Assistant¹, Paul T Seed MSc CStat Senior Lecturer in Medical Statistics¹, Kate Bramham PhD Clinical Senior Lecturer in Nephrology^2, Lucy C Chappell PhD NIHR Research Professor in Obstetrics¹, Fergus P McCarthy PhD Clinical Senior Lecturer in Obstetrics and Gynaecology^1,3.

OBJECTIVES

To determine whether glycogen phosphorylase isoenzyme B (GPBB) and/or brain natriuretic peptide (BNP) concentrations are elevated in pre-eclampsia and superimposed pre-eclampsia (SPE), demonstrating cardiac ischaemia and strain.

STUDY DESIGN

A nested case-control study was performed using samples and clinical data available from a prospective pregnancy cohort. Four groups were selected: healthy pregnant controls (n = 21), pre-eclampsia (n = 19), pre-existing chronic hypertension (CHT) and/or chronic kidney disease (CKD) without (n = 20) or with superimposed pre-eclampsia (SPE) (n = 19). Plasma samples were taken at time of disease or the third trimester in controls.

MAIN OUTCOME MEASURES

Plasma concentrations of GPBB and BNP.

RESULTS

There was no significant difference in GPBB plasma concentrations between controls and pre-eclampsia (geometric mean (GM) [95% CI]: 4.74 [2.54-8.84]ng/mL vs 5.01 [2.58-9.74]ng/mL, p = 0.90)), or between CHT and/or CKD and SPE (GM [95% CI]: 9.49 [4.93-18.25]ng/mL vs 10.24 [5.27-19.92]ng/mL, p = 0.87). BNP plasma concentrations were significantly raised in women with pre-eclampsia compared to controls (GM [95% CI]: 31.83 [20.18-50.22]pg/mL vs 11.33 [7.34-17.51]pg/mL, p = 0.001). Women with CKD, but not CHT, who developed SPE had elevated BNP concentrations. There were no significant differences in BNP concentration between women with comorbidity (CHT and/or CKD) and controls.

CONCLUSIONS

GPBB has a limited role as a biomarker in hypertensive disorders of pregnancy. BNP concentrations were elevated in pre-eclampsia compared to controls. This suggests cardiac strain at the time of pre-eclampsia. Further studies are needed to examine whether BNP can identify women at increased risk of cardiovascular disease.

A rapid reporter assay for recombinant human brain natriuretic peptide (rhBNP) by GloSensor technology

Accurate determination of biological activity is essential in quality control of recombinant human brain natriuretic peptide (rhBNP). In previous study, we successfully developed a genetically modified cell line 293GCAC3-based ELISA assay for rhBNP. But ELISA procedure is still tedious, so this study was aimed to develop a rapid and simple bioassay for rhBNP using GloSensor technology, which provides a platform of flexible luciferase-based biosensors for real-time detection of signaling events in live cells, including cGMP production. A reporter cell line 293GCAGlo-G1 was constructed by transfecting pGloSensor™ 40 F plasmid into 293GCAC3. The reporter assay based on 293GCAGlo-G1 showed high precision with intra-assay CV being 8.3% and inter-assay CV being 14.1%; high accuracy with 80%, 100% and 120% recovery rate being 99.2%, 102.4% and 99.0% respectively; and great linearity with R² of linear fitting equation being 0.99. Besides, no significant difference was found in test results of reporter assay and 293GCAC3-based ELISA assay (paired t test, p = 0.630). All these results suggested that the reporter assay was a viable assay for biological determination of rhBNP.

Usefulness of Serum B-Type Natriuretic Peptide Levels in Comatose Patients Resuscitated from Out-of-Hospital Cardiac Arrest to Predict Outcome

N-terminal pro-B-type natriuretic (NT-proBNP) is expressed in the heart and brain, and serum levels are elevated in acute heart and brain diseases. We aimed to assess the possible association between serum levels and neurological outcome and death in comatose patients resuscitated from out-of-hospital cardiac arrest (OHCA). Of the 939 comatose OHCA patients enrolled and randomized in the Targeted Temperature Management (TTM) trial to TTM at 33°C or 36°C for 24 hours, 700 were included in the biomarker substudy. Of these, 647 (92%) had serum levels of NT-proBNP measured 24, 48, and 72 hours after return of spontaneous circulation (ROSC). Neurological outcome was evaluated by the Cerebral Performance Category (CPC) score and modified Rankin Scale (mRS) at 6 months. Six hundred thirty-eight patients (99%) had serum NT-proBNP levels ≥125 pg/ml. Patients with TTM at 33°C had significantly lower NT-proBNP serum levels (median 1,472 pg/ml) than those in the 36°C group (1,914 pg/ml) at 24 hours after ROSC, p <0.01 but not at 48 and 72 hours. At 24 hours, an increase in NT-proBNP quartile was associated with death (Plogrank <0.0001). In addition, NT-proBNP serum levels > median were independently associated with poor neurological outcome (odds ratio, ORCPC 2.02, CI 1.34 to 3.05, p <0.001; ORmRS 2.28, CI 1.50 to 3.46, p <0.001) adjusted for potential confounders. The association was diminished at 48 and 72 hours after ROSC. In conclusion, NT-proBNP serum levels are increased in comatose OHCA patients. Furthermore, serum NT-proBNP levels are affected by level of TTM and are associated with death and poor neurological outcome.

Brain Natriuretic Peptide and the Severity of Aortic Regurgitation: Is There Any Correlation?

We aimed to evaluate the correlation between aortic regurgitation severity and brain natriuretic (BNP) levels as a marker for left ventricular dysfunction. Sixty consecutive male patients (mean age 22 ± 3 years) with isolated chronic aortic regurgitation were enrolled in the study together with a control group of 30 age-matched healthy volunteers (group A). Patients were classified with regard to aortic regurgitation vena contracta width as follows: group B, < 3 mm, mild ( n = 16); group C, ≥ 3 and < 6 mm, moderate ( n = 26); group D, ≥ 6 mm, severe ( n = 18). BNP measurements were performed with a fluorescence immunoassay kit. BNP levels were increased in patients with aortic regurgitation, and severity of regurgitation had a significant influence on BNP levels. This effect can be explained by the volume loading effect of aortic regurgitation.

Efficacy and safety of nesiritide in patients with decompensated heart failure: a meta-analysis of randomised trials

OBJECTIVES

Current evidence suggests that nesiritide may have effects on renal function and decrease the incidence of mortality. However, a clear superiority using nesiritide in terms of renal toxicity and mortality in patients with heart failure was not consistently proven by previous studies. We performed a meta-analysis of all randomised trials to obtain the best estimates of efficacy and safety of nesiritide for the initial treatment of decompensated heart failure.

METHOD

We performed a meta-analysis of randomised trials of nesiritide in patients with decompensated heart failure (n=38,064 patients, in 22 trials). Two reviewers independently extracted data. Data on efficacy and safety outcomes were collected. We calculated pooled relatives risk (RRs), weighted mean difference and associated 95% CIs.

RESULTS

Compared with placebo, dobutamine and nitroglycerin, nesiritide indicated no increasing risk of total mortality. Compared with the combined control therapy, nesiritide was associated with non-significant differences in short-term mortality (RR 1.24; 95% CI 0.85 to 1.80; p=0.27), mid-term mortality (RR 0.86; 95% CI 0.60 to 1.24; p=0.42) and long-term mortality (RR 0.94; 95% CI 0.75 to 1.18; p=0.61). Nesiritide therapy increased the risk of hypotension (p<0.00 001) and bradycardia (p=0.02) when compared with control therapy. Compared with dobutamine or placebo therapy, no differences in serum creatinine, blood urea nitrogen and creatinine clearance, and no risk of the need for dialysis was observed in nesiritide therapy.

CONCLUSIONS

Our findings indicated that, in patients with heart failure, nesiritide was not associated with the risk of mortality. However, it increased the risk of cardiovascular adverse events. The change of serum creatinine and creatinine clearance had no significant difference, and no risk of the need for dialysis was observed after low-dose nesiritide treatment.

Tanshinone IIA Prevents Leu27IGF-II-Induced Cardiomyocyte Hypertrophy Mediated by Estrogen Receptor and Subsequent Akt Activation

IGF-IIR plays important roles as a key regulator in myocardial pathological hypertrophy and apoptosis, which subsequently lead to heart failure. Salvia miltiorrhiza Bunge (Danshen) is a traditional Chinese medicinal herb used to treat cardiovascular diseases. Tanshinone IIA is an active compound in Danshen and is structurally similar to 17[Formula: see text]-estradiol (E[Formula: see text]. However, whether tanshinone IIA improves cardiomyocyte survival in pathological hypertrophy through estrogen receptor (ER) regulation remains unclear. This study investigates the role of ER signaling in mediating the protective effects of tanshinone IIA on IGF-IIR-induced myocardial hypertrophy. Leu27IGF-II (IGF-II analog) was shown in this study to specifically activate IGF-IIR expression and ICI 182,780 (ICI), an ER antagonist used to investigate tanshinone IIA estrogenic activity. We demonstrated that tanshinone IIA significantly enhanced Akt phosphorylation through ER activation to inhibit Leu27IGF-II-induced calcineurin expression and subsequent NFATc3 nuclear translocation to suppress myocardial hypertrophy. Tanshinone IIA reduced the cell size and suppressed ANP and BNP, inhibiting antihypertrophic effects induced by Leu27IGF-II. The cardioprotective properties of tanshinone IIA that inhibit Leu27IGF-II-induced cell hypertrophy and promote cell survival were reversed by ICI. Furthermore, ICI significantly reduced phospho-Akt, Ly294002 (PI3K inhibitor), and PI3K siRNA significantly reduced the tanshinone IIA-induced protective effect. The above results suggest that tanshinone IIA inhibited cardiomyocyte hypertrophy, which was mediated through ER, by activating the PI3K/Akt pathway and inhibiting Leu27IGF-II-induced calcineurin and NFATC3. Tanshinone IIA exerted strong estrogenic activity and therefore represented a novel selective ER modulator that inhibits IGF-IIR signaling to block cardiac hypertrophy.

Regulation of B-type natriuretic peptide synthesis by insulin in obesity in male mice

Human studies suggest that insulin resistance and obesity are associated with a decrease in B-type natriuretic peptide (BNP) plasma concentrations. The objective of the study was to gain insights into the mechanisms involved in the association between insulin resistance and decreased BNP plasma concentrations. Mice fed a high-fat, high-fructose (HFHF) diet for 4 weeks developed mild obesity and systemic insulin resistance. Elevated plasma concentrations of insulin, glucose and triglycerides were noted. The HFHF diet was also associated with myocardial insulin resistance, characterized by an impaired response of the phosphoinositide 3-kinase-AKT (PI3K-AKT) pathway to insulin in the left ventricle. Myocardial BNP expression and protein were decreased in HFHF-fed mice compared with control animals. Exposure of cardiomyocytes to 100 nm insulin activated PI3K-AKT signalling (15 min) and induced a 1.9 ± 0.3-fold increase in BNP gene expression (6 h). Prolonged exposure of cardiomyocytes to a high insulin concentration (100 nm) for 48 h induced insulin resistance, characterized by an impaired response of the PI3K-AKT signalling pathway and a decreased response of the BNP gene expression to insulin. The decreased response in BNP gene expression was reproduced by treating cardiomyocytes for 7 h with a PI3-kinase inhibitor (wortmannin). In conclusion, HFHF diet in vivo, prolonged exposure to an elevated concentration of insulin or inhibition of the PI3K-AKT pathway in vitro all decrease BNP mRNA levels; this decrease may in turn contribute to the decreased BNP peptide concentrations in plasma observed in insulin-resistant individuals.

Clinical value of natriuretic peptides in chronic kidney disease

According to several lines of evidence, natriuretic peptides (NP) are the main components of a cardiac-renal axis that operate in clinical conditions of decreased cardiac hemodynamic tolerance to regulate sodium homeostasis, blood pressure and vascular function. Even though it is reasonable to assume that NP may exert a relevant role in the adaptive response to renal mass ablation, evidence gathered so far suggest that this contribution is probably complex and dependent on the type and degree of the functional mass loss. In the last years NP have been increasingly used to diagnose, monitor treatment and define the prognosis of several cardiovascular (CV) diseases. However, in many clinical settings, like chronic kidney disease (CKD), the predictive value of these biomarkers has been questioned. In fact, it is now well established that renal function significantly affects the plasmatic levels of NP and that renal failure is the clinical condition associated with the highest plasmatic levels of these peptides. The complexity of the relation between NP plasmatic levels and CV and renal functions has obvious consequences, as it may limit the predictive value of NP in CV assessment of CKD patients and be a demanding exercise for clinicians involved in the daily management of these patients. This review describes the role of NP in the regulatory response to renal function loss and addresses the main factors involved in the clinical valorization of the peptides in the context of significant renal failure.

Heart failure in patients with chronic kidney disease: a systematic integrative review

Introduction. Heart failure (HF) is highly prevalent in patients with chronic kidney disease (CKD) and end-stage renal disease (ESRD) and is strongly associated with mortality in these patients. However, the treatment of HF in this population is largely unclear. Study Design. We conducted a systematic integrative review of the literature to assess the current evidence of HF treatment in CKD patients, searching electronic databases in April 2014. Synthesis used narrative methods. Setting and Population. We focused on adults with a primary diagnosis of CKD and HF. Selection Criteria for Studies. We included studies of any design, quantitative or qualitative. Interventions. HF treatment was defined as any formal means taken to improve the symptoms of HF and/or the heart structure and function abnormalities. Outcomes. Measures of all kinds were considered of interest. Results. Of 1,439 results returned by database searches, 79 articles met inclusion criteria. A further 23 relevant articles were identified by hand searching. Conclusions. Control of fluid overload, the use of beta-blockers and angiotensin-converting enzyme inhibitors or angiotensin receptor blockers, and optimization of dialysis appear to be the most important methods to treat HF in CKD and ESRD patients. Aldosterone antagonists and digitalis glycosides may additionally be considered; however, their use is associated with significant risks. The role of anemia correction, control of CKD-mineral and bone disorder, and cardiac resynchronization therapy are also discussed.

Plasma B-type natriuretic peptide study in children with severe enterovirus 71 infection: a pilot study

OBJECTIVES

Severe enterovirus 71 (EV71) infections in children can result in acute heart failure. B-type natriuretic peptide (BNP) is a good biomarker of myocardial stress. The purpose of this study was to use plasma BNP for the detection of EV71 infection with cardiac involvement.

METHODS

Patients with severe EV71 infections and healthy control subjects were studied: group 1 (n=30), normal controls; group 2 (n=20), EV71 infection with central nervous system involvement; and group 3 (n=3), EV71 infection with cardiopulmonary failure. The demographic and laboratory data including plasma BNP levels were analyzed statistically.

RESULTS

All group 2 patients recovered completely without neurological sequelae, and all group 3 patients survived without cardiac complications. Group 3 patients had higher troponin I, MB fraction of creatine kinase, and BNP levels than patients of the other groups. The median BNP values were <5 pg/ml in group 1, 9.5 pg/ml in group 2, and 238 pg/ml in group 3. Using a BNP cut-off value of 100 pg/ml to identify cases with severe EV71 infection and acute heart failure, the sensitivity and specificity were both 100%.

CONCLUSIONS

Children with severe EV71 infections have varying degrees of myocardial stress. Plasma BNP would be a sensitive and reliable biomarker for the detection of cardiac involvement in children with severe EV71 infections.

Oral drug delivery systems using chemical conjugates or physical complexes

Oral delivery of therapeutics is extremely challenging. The digestive system is designed in a way that naturally allows the degradation of proteins or peptides into small molecules prior to absorption. For systemic absorption, the intact drug molecules must traverse the impending harsh gastrointestinal environment. Technologies, such as enteric coating, with oral dosage formulation strategies have successfully provided the protection of non-peptide based therapeutics against the harsh, acidic condition of the stomach. However, these technologies showed limited success on the protection of therapeutic proteins and peptides. Importantly, inherent permeability coefficient of the therapeutics is still a major problem that has remained unresolved for decades. Addressing this issue in the context, we summarize the strategies that are developed in enhancing the intestinal permeability of a drug molecule either by modifying the intestinal epithelium or by modifying the drug itself. These modifications have been pursued by using a group of molecules that can be conjugated to the drug molecule to alter the cell permeability of the drug or mixed with the drug molecule to alter the epithelial barrier function, in order to achieve the effective drug permeation. This article will address the current trends and future perspectives of the oral delivery strategies.

Plasma B-type natriuretic peptide in predicting outcomes of elective coronary artery bypass surgery

The risks of surgery and its clinical outcome are of great importance for both patients and physicians when choosing coronary artery bypass (CABG) surgery for coronary artery disease. The purpose of the current study was to clarify the relationship between serum B-type natriuretic peptide (BNP) and patient clinical outcome. Seventy-six eligible patients who underwent CABG were enrolled into the prospective study. Venous blood samples were drawn for serum BNP and N-terminal (NT)-proBNP levels measurement on preoperative Day 1, postoperative Day 1, and postoperative Day 7. Clinical end points were: (1) intensive care unit (ICU) stay longer than 4 days postoperatively and/or hospital stay longer than 13 days postoperatively; (2) major complications and poor outcomes. Patients who had prolonged ICU stay and hospitalization had significantly higher postoperative Day 1 BNP and postoperative Day 1 NT-proBNP level (p = 0.02 and 0.005, respectively). Age was significantly older in patients with prolonged ICU stay and hospitalization than those without prolonged ICU stay and hospitalization (p = 0.03). Serum creatinine level was also significantly increased in patients with prolonged ICU stay and hospitalization (p = 0.009). However, age was the only remaining factor that correlated with prolonged ICU stay and hospitalization in the multivariate logistic regression model. These results suggest that research using BNP and NT-proBNP for predicting ICU stay and hospitalization in patients who have undergone CABG must adjust risk factors to present a more appropriate estimation of its clinical outcome.

The NT-ProBNP Test in Subjects with End-Stage Renal Disease on Hemodialysis Presenting with Acute Dyspnea: Is Knowing Worth the Cost?

Background. The NT-ProBNP/BNP test has been validated as a marker for determining the etiology of acute dyspnea. In the setting of end-stage renal disease on hemodialysis (ESRD on HD), the utility of the NT-ProBNP/BNP test has not been validated. This study examines the clinical utility of the NT-ProBNP test in the setting of ESRD on HD patients presenting with acute dyspnea. Methods. A retrospective case series of 250 subjects were admitted to Cooper University Hospital, 07/2010-03/2011, with ESRD and HD presenting with dyspnea. The incidences of echocardiography, cardiology consultation, and NT-ProBNP elevated and normal were examined. Correlation coefficients were calculated for NT-ProBNP with age (years), estimated dry weight (kg), amount of fluid removed (L), and ejection fraction (EF in %) among other echocardiography parameters. Results. Of the total sample 235 patients had NT-ProBNP levels performed. Cardiology consults were placed in 68.8% and 58% who underwent echocardiography. Of those for whom an echocardiography was performed estimated mean EFs of 54.6%, 50.8%, and 61.7% were observed among the NT-ProBNP elevated group, normal group, and no NT-ProBNP group, respectively. No differences were detected in all other echocardiography measurements. No correlation was observed between NT-ProBNP and age (r = 0.05), baseline EDW (r = -0.09), amount of fluid removed (r = 0.07), or EF (r = 0.02). Conclusion. In the setting of ESRD on HD, the NT-ProBNP test has no clinical utility in determining the etiology of acute dyspnea. This can be demonstrated through echocardiographic and therapeutic parameters measured in this study.

M-atrial natriuretic peptide: a novel antihypertensive protein therapy

The natriuretic peptides, specifically atrial natriuretic peptide (ANP), are increasingly recognized to play a fundamental role in blood pressure (BP) regulation. This role in BP regulation reflects the pluripotent cardiorenal actions of ANP, which include diuresis, enhancement of renal blood flow and glomerular filtration rate, systemic vasodilatation, suppression of aldosterone, and inhibition of the sympathetic nervous system. These actions of ANP, in addition to recent human studies demonstrating an association of higher plasma ANP with lower risk of hypertension, support the development of an ANP-based therapy for hypertension. M-ANP is a novel ANP-based peptide that is resistant to proteolytic degradation and possesses greater BP-lowering, renal function-enhancing, and aldosterone-suppressing properties than native ANP. In an animal model of hypertension, M-ANP lowers BP via multiple mechanisms, including vasodilatation, diuresis, and inhibition of aldosterone. Importantly, M-ANP enhances both glomerular filtration rate and renal blood flow despite reductions in BP. The pluripotent BP-lowering actions and concomitant enhancement of renal function associated with M-ANP are highly attractive characteristics for an antihypertensive agent and underscore the therapeutic potential of M-ANP. M-ANP currently is heading into clinical testing, which may advance this novel strategy for human hypertension.

Induction of brain natriuretic peptide and monocyte chemotactic protein-1 gene expression by oxidized low-density lipoprotein: relevance to ischemic heart failure

Brain natriuretic peptide (BNP) and monocyte chemotactic protein-1 (MCP-1) are biomarkers of heart failure (HF). The aim of the present study was to determine the role of oxidized low-density lipoprotein (Ox-LDL) in the induction of these biomarkers and the signaling pathways involved in vitro. Incubation of HL-1 cardiomyocytes and human myocytes with Ox-LDL induced the expression of BNP and MCP-1 genes, while native LDL had no effect. When peroxides associated with Ox-LDL were reduced to hydroxides, the ability to induce BNP and MCP-1 gene expression was abolished. Furthermore, exposure of HL-1 cells to ischemic conditions alone had no effect on BNP gene expression, while ischemia followed by reperfusion resulted in increased expression of BNP gene. Inhibitors of ERK and JNK inhibited the induction of BNP. Signaling array results suggested that the induction of both MAPK and NF-κB pathways is involved in the induction of BNP by Ox-LDL. These results suggest that Ox-LDL or peroxidized lipids formed in oxidatively stressed myocytes during ischemia-reperfusion injury may play a role in the induction of BNP and MCP-1.

Brain natriuretic peptide measurement in pulmonary medicine

Serum levels of natriuretic peptides are well established as important biomarkers in patients with cardiac disease. Less attention has been placed on the role of natriuretic peptides in patients with pulmonary conditions. In several well-defined groups of patients with pulmonary disease natriuretic peptides provide the clinician with clinically valuable information. A limitation of the interpretation of natriuretic peptides in pulmonary disease is the confounding effect of concurrent conditions such as heart failure, hypoxia, sepsis and renal failure. The present paper reviews the role of natriuretic peptides for diagnosis, risk stratification and prognosis of several pulmonary disorders.

Natriuretic Peptide testing in primary care

The incidence, as well as the morbidity and mortality associated with heart failure (HF) continue to rise despite advances in diagnostics and therapeutics. A recent advance in the diagnostic and therapeutic approach to HF is the use of natriuretic peptide (NP) testing, including both B-type natriuretic peptide (BNP) and its amino terminal cleavage equivalent (NT-proBNP). NPs may be elevated at an early stage among those with symptoms as well among those without. The optimal approach for applying NP testing in general populations is to select the target population and optimal cut off values carefully. Superior diagnostic performance is observed among those with higher baseline risk (such as hypertensives or diabetics). As well, unlike for acute HF, the cut off value for outpatient testing for BNP is 20-40 pg/mL and for NTproBNP it is 100-150 ng/L. In symptomatic primary care patients, both BNP and NT-proBNP serve as excellent tools for excluding HF based on their excellent negative predictive values and their use may be cost effective. Among those with established HF, it is logical to assume that titration of treatment to achieve lower NPs levels may be advantageous. There are several ongoing trials looking at that prospect.

N-terminal pro-B-type natriuretic peptide in early and advanced phases of obesity

BACKGROUND

Increased plasma amino-terminal-cleavage-fragment of NP (NT-proBNP) is an established indicator for heart failure. Moreover, obese adults had low circulating NT-proBNP suggesting an obesity-related dysregulation (natriuretic handicap). Secretion and/or clearance of NT-proBNP were discussed to be impaired in obesity. As only older adults were investigated so far, it remains unclear when during the evolution of obesity the state of a natriuretic handicap develops, and whether NT-proBNP may still serve as a relevant cardiac marker in obese juveniles.

METHODS

We analysed NT-proBNP in juvenile (n=274, 10-18 years) and middle-aged (n=277, 18-50 years) normal weight (n=213) and obese (n=338) probands together with complex anthropometry, carotis sonography, clinical, and laboratory parameters.

RESULTS

NT-proBNP showed a significant gender and age interaction. Adult females had significant higher NT-proBNP than adult males, and higher levels than juvenile females. Adult males had lower levels than juvenile males. Only a weak age and weight interaction was seen with obese juveniles which showed higher NT-proBNP than obese adults. Moreover, normal weight probands had higher NT-proBNP than overweight and obese. In a multiple regression including all probands, gender, creatinine and uric acid were the best predictors for NT-proBNP. In adults, female gender is the strongest driver for increased NT-proBNP.

CONCLUSIONS

These results argue against an essential influence of obesity to B-type cardiac natriuretic hormone system regulation in the absence of heart failure, and suggest NT-proBNP as a useful cardiac marker irrespective of age and obesity.

Human pro-B-type natriuretic peptide is processed in the circulation in a rat model

BACKGROUND

The appearance of B-type natriuretic peptide (BNP) in the blood is ultimately caused by proteolytic processing of its precursor, proBNP. The mechanisms leading to the high plasma concentration of unprocessed proBNP are still poorly understood. The goals of the present study were to examine whether processing of proBNP takes place in the circulation and to evaluate the clearance rate of proBNP and proBNP-derived peptides.

METHODS

We studied the processing of human proBNP in the circulation and the clearance rate of proBNP and proBNP-derived peptides (BNP and N-terminal fragment of proBNP, NT-proBNP) in rats by injecting the corresponding peptides and analyzing immunoreactivity at specific time points. Glycosylated and nonglycosylated proBNP and NT-proBNP were used in the experiments. We applied immunoassays, gel filtration, and mass spectrometry (MS) techniques to analyze the circulation-mediated processing of proBNP.

RESULTS

ProBNP was effectively processed in the circulation into BNP (1-32) and various truncated BNP forms as confirmed by gel filtration and MS analysis. Glycosylation of proBNP close to the cleavage-site region suppressed its processing in the circulation. The terminal half-life for human glycosylated proBNP was 9.0 (0.5) min compared with 6.4 (0.5) min for BNP. For NT-proBNP, the terminal half-lives were 15.7 (1.4) min and 15.5 (1.3) min for glycosylated and nonglycosylated forms, respectively.

CONCLUSIONS

In rats, processing of human proBNP to active BNP occurs in the circulation. The clearance rate of proBNP is quite similar to that of BNP. These observations suggest that peripheral proBNP processing may be an important regulatory step rather than mere degradation.

Biochemistry of the human B-type natriuretic peptide precursor and molecular aspects of its processing

B-type Natriuretic Peptide (BNP) is a circulating hormone primarily produced by the myocardium in response to volume overload and increased filling pressure. BNP acts to increase natriuresis and to decrease cardiac load and blood pressure. The appearance of active BNP hormone in the bloodstream is preceded by the proteolytic cleavage of its precursor, proBNP. The products of proBNP processing, BNP and the N-terminal fragment of proBNP (NT-proBNP), have been extensively shown to be powerful biomarkers of heart failure (HF) and risk assessments for cardiovascular complications. In contrast to the clinical utility of proBNP-derived peptides, knowledge of posttranslational proBNP maturation and molecular aspects of its processing are far from being completely comprehended. A clear understanding of proBNP processing mechanisms in normal and diseased states appears to be required to improve our understanding of HF development and the clinical significance of both proBNP and proBNP-derived peptides. The aim of the present review is to summarize the available data in the field of human proBNP maturation and processing and to discuss potential clinical implications.

Current perspectives on diagnosis of heart failure in long-term dialysis patients

Cardiovascular disease is highly prevalent in patients with chronic kidney failure treated using dialysis. The risk of cardiovascular events is estimated to be at least 2- to 10-fold higher in dialysis patients than in age-, race-, and sex-matched persons with normal kidney function. A significant proportion of cardiovascular events in long-term dialysis patients is caused by heart failure, and the presence of heart failure is predictive of a poor prognosis. Despite the significant morbidity and mortality associated with heart failure, very few therapeutic options are proved to prevent and treat the progression of this complication in dialysis patients. There are several potential reasons for this, chiefly reflecting both challenges with diagnosis due to the coexistence of volume overload and a paucity of adequately powered prospective randomized controlled trials that examine the efficacy of different therapeutic options in dialysis patients with cardiac disease or heart failure. Thus, unlike in the general population, very few advances have been made in managing this severe complication in dialysis patients. In this article, an overview of the prevalence, severity, and risk factors for heart failure in maintenance dialysis patients is provided and the diagnosis of heart failure in these patients is revisited.

Practical application of natriuretic peptides in paediatric cardiology

It is still uncertain if cardiac natriuretic peptides are useful biomarkers in paediatric cardiology. In this review we identify four clinical scenarios in paediatric cardiology, where clinical decision-making can be difficult, and where we feel the paediatric cardiologists need additional diagnostic tools. Natriuretic peptide measurements could be that extra tool. We discuss and suggest N-terminal pro-B-type natriuretic peptide and B-type natriuretic peptide reference intervals for children without cardiovascular disease and cut-off points for the four specific paediatric heart conditions. We conclude that in premature neonates with persistent arterial ducts; in teenagers with tetralogy of Fallot and pulmonary regurgitation; and in children with heart transplants and potential allograft rejection cardiac peptides can provide the clinician with additional information, but in children with atrial septal defects the peptides are not helpful in guiding treatment or follow-up.

Irrelevant B-type natriuretic peptide levels in patients with mechanical prostheses in the mitral position presenting with congestive heart failure

BACKGROUND

Plasma B-type natriuretic peptide (BNP) level is reported to be a strong marker of congestive heart failure (CHF). Heterogeneity of the BNP levels among individuals with CHF, however, can cause confusion in interpreting the results. The influence of mitral mechanical prostheses on BNP levels in patients presenting with CHF is not well known.

METHODS AND RESULTS

In the present study 214 consecutive patients with CHF diagnosed using the Framingham criteria were enrolled and divided into 2 groups with and without mitral mechanical prostheses (prosthesis group, n=31; native group, n=183). The plasma BNP levels were measured, and clinical examinations including echocardiography were performed at the same time to assess cardiac performance. There was no difference in the left ventricular ejection fractions between the 2 groups. Despite having a lower body mass index, larger prevalence ratio of atrial fibrillation and larger size of the left atrium, the prosthesis group had a significantly lower logBNP level than the native group (prosthesis group vs native group: 5.12+/-1.01 vs 6.21+/-0.92, P<0.001; BNP level: 167+/-324 pg/ml vs 498+/-380 pg/ml). On multivariate analysis the presence of a mitral mechanical prosthesis was extracted as an independent predictor for decreased BNP level in patients with CHF.

CONCLUSIONS

Plasma BNP level cannot correctly reflect the severity of CHF in patients with mechanical prostheses in the mitral position.

Processing of pro-B-type natriuretic peptide: furin and corin as candidate convertases

BACKGROUND

B-type natriuretic peptide (BNP) and its N-terminal fragment (NT-proBNP) are the products of the enzyme-mediated cleavage of their precursor molecule, proBNP. The clinical significance of proBNP-derived peptides as biomarkers of heart failure has been explored thoroughly, whereas little is known about the mechanisms of proBNP processing. We investigated the role of 2 candidate convertases, furin and corin, in human proBNP processing.

METHODS

We measured proBNP expression in HEK 293 and furin-deficient LoVo cells. We used a furin inhibitor and a furin-specific small interfering RNA (siRNA) to explore the implication of furin in proBNP processing. Recombinant proBNPs were incubated with HEK 293 cells transfected with the corin-expressing plasmid. We applied mass spectrometry to analyze the products of furin- and corin-mediated cleavage.

RESULTS

Reduction of furin activity significantly impaired proBNP processing in HEK 293 cells. Furin-deficient LoVo cells were unable to process proBNP, whereas coexpression with furin resulted in effective proBNP processing. Mass spectrometric analysis revealed that the furin-mediated cleavage of proBNP resulted in BNP 1-32, whereas corin-mediated cleavage led to the production of BNP 4-32. Some portion of proBNP in the plasma of heart failure patients was not glycosylated in the cleavage site region and was susceptible to furin-mediated cleavage.

CONCLUSIONS

Both furin and corin are involved in the proBNP processing pathway, giving rise to distinct BNP forms. The significance of the presence of unprocessed proBNP in circulation that could be cleaved by the endogenous convertases should be further investigated for better understanding BNP physiology.

Clinical and functional characterisation of rheumatic mitral regurgitation in children and adolescents including the brain natriuretic peptide

Rheumatic fever is a public health problem of universal distribution, predominantly affecting individuals in developing countries. In individuals less than 20 years of age, pure mitral regurgitation is the most commonly found condition in chronic rheumatic valve disease. In the present study, rheumatic mitral regurgitation was assessed in children and adolescents, addressing its clinical (duration of the disease, symptoms, use of benzathine penicillin, and number of outbreaks of the acute phase of rheumatic fever), electrocardiographic (left atrium abnormality and/or left ventricle hypertrophy) and echocardiographic characteristics (left atrium and ventricle measurements, ejection fraction and pulmonary artery pressure), as well as plasma dose of N-terminal portion of the brain natriuretic peptide through electrochemiluminescence immunoassay. Fifty-three patients were studied. The patients had moderate (41.5%) or severe (58.5%) rheumatic mitral regurgitation; had not undergone surgery; were not in the acute phase of the disease; and were being treated at a paediatric cardiology reference hospital in Northeastern Brazil. Mean patient age was 10.6 years (minimum of 3 and maximum of 19 years). With the exception of the ejection fraction, the echocardiographic variables had a significant correlation to the natriuretic peptide, demonstrating that this hormone reflects the haemodynamic consequences of mitral regurgitation. It was concluded that cardiac remodelling that occurs in rheumatic mitral regurgitation in children and adolescents leads to the production of the brain natriuretic peptide, which could be used as a complementary diagnostic tool in the follow-up of such patients.

N-terminal ProBNP distribution and correlations with biological characteristics in apparently healthy Greek population: ATTICA study

Brain natriuretic peptides are widely used as biomarkers of cardiovascular diseases and mainly heart failure. However, these markers are often found to be high even in apparently healthy participants, and little is known about which factors contribute to physiological change in plasma brain natriuretic peptide (BNP) and amino-terminal pro-B-type natriuretic peptide (NTproBNP) concentration in general populations. In this study, a random subsample of the ATTICA study was used (486 individuals) and serum NT-proBNP was measured. Approximately 20% of the participants had no detectable NT-proBNP values. Women had higher values of NT-proBNP than men (median [25th-75th percentiles]: 30.2 [15.8-54.3] vs 14.9 [4.0-28.1] pg/mL, P < .001]. Amino-terminal pro-B-type natriuretic peptide values were positively correlated with age (rho = .140, P = .006) and inversely with body mass index (BMI; rho = -.142, P = .005), creatinine (Cr) clearance (rho = -.349, P < .001), and hemoglobin (rho = -.249, P < .001) values. Linear regression analysis revealed that gender is the main contributor of NT-proBNP levels, followed by age, BMI, and Cr values.

Prolonged effects of B-type natriuretic peptide infusion on cardiac remodeling after sustained myocardial injury

B-type natriuretic peptide (BNP) is an established first-line therapy for acute decompensated heart failure (HF), but its efficacy in preventing left ventricular (LV) remodeling after myocardial injury is unknown. The goal of this study was to evaluate the effects of BNP therapy on remodeling after ischemic injury in an awake canine model. Dogs were chronically instrumented for hemodynamics. Ischemia was created by daily coronary embolization (Embo; 3.1 x 10(4) beads/day) for 3 wk; 60 min after the first embolization, BNP (100 ng x kg(-1) x min(-1); n = 6) or saline (control; n = 6) was continuously infused via a left atrial catheter for 3 wk. Hemodynamics and echocardiography were performed in an awake state at baseline, 3 wk after Embo + BNP infusion, and 4 wk after stopping Embo + BNP infusion. End-systolic elastance (E(es)) and LV change in pressure over time (dP/dt) were preserved throughout Embo + BNP therapy versus control therapy (E(es): 3.76 +/- 1.01 vs. 1.41 +/- 0.16 mmHg/ml; LV dP/dt: 2,417 +/- 96 vs. 2,068 +/- 95 mmHg/s; both P < 0.05 vs. control). LV end-diastolic dimension was significantly smaller in BNP-treated dogs compared with control dogs (4.29 +/- 0.10 vs. 4.77 +/- 0.17 cm), and ejection fraction was maintained in treated dogs vs. control dogs (53 +/- 1% vs. 46 +/- 2%) (both P < 0.05 vs. control). Cyclooxygenase (COX)-2 expression in terminal LV tissue was significantly reduced after BNP therapy. Treatment with continuous infusion of BNP preserved LV geometry, improved systolic function, and prevented the progression of systolic HF after persistent ischemic injury.

Acute hemodynamic effects of intravenous nesiritide on left ventricular diastolic function in heart failure patients

BACKGROUND

Nesiritide is recombinant human B-type natriuretic peptide with vasodilatory effects used in patients with decompensated congestive heart failure. We sought to evaluate the effects of nesiritide on left ventricular diastolic function in heart failure patients.

METHODS AND RESULTS

Twenty-five heart failure patients underwent left heart catheterization (using a pressure-volume conductance catheter) and echocardiography at baseline and 30 minutes after an intravenous bolus and infusion of nesiritide. Invasive and noninvasive measurements of load-dependent (deceleration time, echocardiographic diastolic function classification, negative dP/dt, left ventricular diastolic pressure, tau) parameters of diastolic function were assessed. The nonlinear slope of the end-diastolic pressure volume relationship (EDPVR) using 2 single-beat methods for measuring left ventricular end-diastolic elastance was calculated to assess load-independent parameters of diastolic function. Nesiritide reduced biventricular diastolic pressure and systemic vascular resistance. Tau and negative dP/dt showed modest improvement. Deceleration time, isovolumetric relaxation time, diastolic stiffness indices (E/E'/stroke volume (SV) and E/E'/left ventricular end-diastolic volume index (LVEDVI)), and the echocardiographic diastolic filling pattern classification did not change. Furthermore, there was no change in the EDPVR.

CONCLUSIONS

Although nesiritide is an effective vasodilator resulting in decreased left ventricular preload and afterload in heart failure patients, intrinsic left ventricular diastolic function did not change acutely, suggesting that nesiritide has no significant acute lusitropic effect.

Role of natriuretic peptides in cGMP production in fetal cardiac bypass

BACKGROUND

We previously showed cyclic guanosine 3',5'-monophosphate (cGMP) levels increase with fetal cardiac bypass despite derangements in the placental nitric oxide pathway. The natriuretic peptides, atrial (ANP), brain (BNP), and c-type (CNP), are common indicators of cardiac distress, and an alternative pathway for cGMP generation. We hypothesized that these natriuretic peptides may account for the paradoxic rise in cGMP seen with fetal bypass.

METHODS

Six ovine fetuses, 106 to 118 days' gestation, underwent cardiac bypass for 30 minutes and were followed for 120 minutes after bypass. Fetal plasma samples were collected before bypass, during bypass, and 30 and 120 minutes after bypass for natriuretic peptide analysis. Results were compared with 6 sham bypass fetuses and cGMP values from another 14 bypass fetuses (to avoid confounding effects of excess blood sampling). Fetal hemodynamics and metabolics were correlated to ANP, BNP, and CNP values. Statistical analysis was by analysis of variance, Student's t test, and best-fit correlations, with significance set at p = 0.05 or less.

RESULTS

The ANP, BNP, and CNP increased with fetal bypass (674 +/- 133 pg/mL, 151 +/- 52 pg/mL, and 295 +/- 45 pg/mL, respectively), remaining elevated after bypass, whereas sham concentrations remained stable at pre-bypass levels. Changes in ANP, BNP, and CNP positively correlated with rising cGMP. There was positive correlation between ANP and CNP and rising fetal lactate levels, but not to other physiologic parameters associated with placental dysfunction.

CONCLUSIONS

There is a substantial rise in natriuretic peptides seen with fetal bypass, likely in part a reflection of myocardial dysfunction. Further, the natriuretic peptide pathway may account for the paradoxic rise in cGMP seen with fetal bypass.

Human coronary atherosclerosis modulates cardiac natriuretic peptide release

Natriuretic peptides (NPs) modulate vasodilatation and vascular remodelling. In human coronary explants, expression of NPs mRNA and their respective receptors is significantly more pronounced with advanced atherosclerotic lesions.

AIMS

We hypothesize that vascular atherosclerosis modulates NP release in vivo during progressive stages of coronary atherosclerosis.

METHODS AND RESULTS

NT-proANP (A) and NT-proBNP (B) were assessed on blood samples of 194 patients. Coronary atherosclerosis was assessed in all patients by angiography and in case of moderate stenosis by fractional flow reserve (FFR), a validated tool for detecting ischemia-inducing stenosis. Significant coronary stenosis was defined as a diameter stenosis (DS) >/=50% and/or positive FFR. Endothelial dysfunction was detected by cold pressure test (CPT) in a subgroup of 99 patients. Patients were divided into: (1) normal group (normal endothelial function, n=19); (2) endothelial dysfunction group (n=17); (3) moderate atherosclerotic group (at least one coronary stenosis <50%, n=86); (4) stenotic group (n=72). A and B were higher in patients with endothelial dysfunction (A: 2951 [1290-3920] fmol/ml; B: 156 [98-170] pg/ml), moderate atherosclerotic (A: 3868 [2250-5890] fmol/ml, p<0.05 vs. normal; B: 162 [84-283] pg/ml) and stenotic group (A: 3934 [2647-5525]; B: 227 [191-784] pg/ml; p<0.05 vs. normal) as compared with normal group (A: 2378 [970-2601] fmol/ml; B: 78 [40-136] pg/ml). During CPT, a mild NT-proANP increase was observed only in patients with endothelial dysfunction (Delta% vs. baseline: 17+/-6, p<0.05). NT-proBNP did not change after CPT in all groups.

CONCLUSION

Well defined stages of atherosclerosis are characterized by progressive increases in NT-proANP and NT-proBNP levels, beginning with endothelial dysfunction and progressively more pronounced with moderate and severe coronary atherosclerosis irrespective of the underlying myocardial disease.

Transient increase in plasma brain (B-type) natriuretic peptide after percutaneous transluminal coronary angioplasty

BACKGROUND

Brain (B-type) natriuretic peptide (BNP) is known to be secreted predominantly from the myocardium. Brain natriuretic peptide plasma concentrations have been shown to be markedly increased in patients with acute myocardial infarction; however, plasma BNP response during episodes of myocardial ischemia has not been established.

HYPOTHESIS

This study was designed to examine plasma BNP in patients with transient myocardial ischemia induced by inflation of a percutaneous transluminal coronary angioplasty (PTCA) balloon.

METHODS

Thirty consecutive patients (26 men and 4 women; mean age 61 years) who underwent PTCA, and another 49 patients (39 men and 10 women; mean age 63 years) who underwent diagnostic coronary angiography were enrolled in this study. Serum BNP concentrations were assayed in all patients.

RESULTS

Plasma BNP was increased significantly with a peak concentration of 66.1 +/- 65.2 pg/ml 24 h after PTCA. Coronary angiography did not cause plasma BNP increase (immediately before 30.4 +/- 29.0 pg/ml, 24 h after 33.7 +/- 30.6 pg/ml). No significant differences were present in hemodynamic parameters measured immediately before and 24 h after PTCA.

CONCLUSION

Plasma BNP is increased by transient myocardial ischemia induced by PTCA.

Right heart dysfunction assessed with echography, B-type natriuretic peptide and cardiopulmonary test in patients with chronic heart failure

BACKGROUND

Right ventricle (RV) impairment could influence brain natriuretic peptide (BNP) circulating levels. It is not well known whether echocardiographic parameters assessing RV function could be related to BNP levels in patients with chronic heart failure (CHF). Controversial data are available about the role played by RV dysfunction in determining exercise capacity in CHF patients.

METHODS

Sixty patients with CHF referred to our CHF Unit underwent blood sampling for BNP levels determination, cardiopulmonary exercise test with VO2 peak, VO2-AT and VE/VCO2 slope assessment and M-mode, two-dimensional and Doppler echocardiography with evaluation of right heart function [right atrial pressure (RAP), pulmonary artery pressure (PAP), severity of tricuspid regurgitation (TR), and tricuspid annular plane systolic excursion (TAPSE)].

RESULTS

A significant correlation was detectable between BNP levels and TAPSE (r = -0.33; P < 0.05), RAP (r = 0.34; P < 0.05), PAP (r = 0.42; P < 0.05), TR (P for trend 0.05); correlation with TAPSE remained significant even in multivariate. VO2 peak was significantly related to RAP (r = -0.38, P < 0.05) and TR (P for trend 0.05); AT with PAP (r = -0.40, P < 0.05), RAP (r = -0.50, P < 0.05), TR (P for trend 0.05). Moreover, patients with TAPSE greater than 16 mm had higher values of VO2 peak (13.68 +/- 3.28 vs. 11.49 +/- 2.37 ml/kg/m', P < 0.05) and of VO2-AT (18.36 +/- 1.60 vs. 10.23 +/- 2.31 ml/kg/m'; P < 0.05).

CONCLUSION

Right heart dysfunction assessed by simple echocardiographic parameters is related to neurohormonal activation featured by increased BNP levels and to a worse functional capacity in CHF patients.

Relationship between Cardiofemoral Index and the plasma concentration of brain natriuretic peptide in anemic fetuses associated with Rh alloimmunization

BACKGROUND

Fetal anemia is a common result of alloimmunization and is an important cause of fetal congestive heart failure resulting in heart dilation. Fetuses suspected of having heart failure present a higher Cardiofemoral Index and an increase in plasma BNP levels, because the cardiac hormonal system is activated by increased heart wall stretch due to increased left ventricular volume and pressure overload.

METHODS

Our group studied 33 pregnant women (22-31 weeks' gestation at the first cordocentesis) referred for intrauterine fetal transfusion due to severe red blood cells isoimmunization. Up to 6 h prior to each cordocentesis, all fetuses were submitted to ultrasonography measurements where the Cardiofemoral Index was calculated. Samples of blood from the umbilical vein were collected for hemoglobin concentration and blood gas measurements. Plasma levels of BNP were determined with the use of plasma that had previously been frozen and thawed once. Plasma BNP was measured by radioimmunoassay. Pearson's correlation test and regression analysis were used to determine the association between the plasma concentration of BNP and the Cardiofemoral Index of the anemic fetuses with RH alloimmunization.

RESULTS

Anemia was severe in 17 (50%) fetuses, mild in 9 (26.47%) and in 8 patients (23.53%) the fetuses were not anemic; hemoglobin ranged from 3.10 to 15.70 g/dl. The Cardiofemoral Index ranged from 0.43 to 0.87 and it was altered (>or=0.59) in 23 fetuses. A significant positive correlation was observed between BNP plasma fetal concentration and Cardiofemoral Index (Pearson r=0.61, P<0.0001).

CONCLUSIONS

These results suggest that fetal plasma concentration of BNP may increase in fetuses with heart dilation leading to a positive association between Cardiofemoral Index and plasma concentration of BNP.

Cerebral salt wasting and elevated brain natriuretic peptide levels after traumatic brain injury: 2 case reports

BACKGROUND

Historically, hyponatremia in patients with varying brain diseases was termed cerebral salt wasting. Hyponatremia secondary to CSW was reported to be a distinct entity from SIADH, with the distinguishing feature of decreased extracellular fluid volume. Brain natriuretic peptide, a peptide with natriuretic, vasorelaxant, and aldosterone-inhibiting properties, was recently implicated in aneurysmal SAH patients with CSW. Here, we describe 2 cases of CSW in TBI patients with elevated BNP levels. This phenomenon has not been previously described.

CASE DESCRIPTION

Two patients with TBI and hyponatremia were subject to analysis. Central lines were placed to assess volume status. Levels of BNP were measured at the onset of hypertonic saline infusion. Electrocardiogram and cardiac enzyme studies were performed to assess cardiac function. Serial imaging was performed to assess the extent of brain injury.

CONCLUSIONS

These patients with TBI had findings consistent with CSW with elevated BNP levels in the setting of normal cardiac function. In both cases, a high BNP level was observed after declining plasma Na levels despite aggressive hypertonic saline infusion. High BNP levels may be associated with CSW. Further studies are necessary to establish a causative role for BNP in TBI-induced CSW.