The effect of diabetes on the diagnostic and prognostic performance of mid-region pro-atrial natriuretic peptide and mid-region pro-adrenomedullin in patients with acute dyspnea

Serum mid-regional pro-atrial natriuretic peptide (MR-proANP) and pro-adrenomedullin (MR-proADM) are novel biomarkers for acute heart failure (AHF). Like other AFH biomarkers, the performance of these tests are affected by the presence of clinical variables such as renal failure and obesity. In a substudy of the Biomarkers from Acute Heart Failure Study, we show that diabetes did not influence the performance of these markers with regards to AHF diagnosis or 90-day all cause death. However, in patients without AHF, increased MR-proADM alone was associated with the presence of diabetes.     

The effect of diabetes on the diagnostic and prognostic performance of mid-region pro-atrial natriuretic peptide and mid-region pro-adrenomedullin in patients with acute dyspnea

Serum mid-regional pro-atrial natriuretic peptide (MR-proANP) and pro-adrenomedullin (MR-proADM) are novel biomarkers for acute heart failure (AHF). Like other AFH biomarkers, the performance of these tests are affected by the presence of clinical variables such as renal failure and obesity. In a substudy of the Biomarkers from Acute Heart Failure Study, we show that diabetes did not influence the performance of these markers with regards to AHF diagnosis or 90-day all cause death. However, in patients without AHF, increased MR-proADM alone was associated with the presence of diabetes.     

Comprehensive plasma metabolomic and lipidomic analyses reveal potential biomarkers for heart failure

Heart failure is a syndrome with symptoms or signs caused by cardiac dysfunction. In clinic, four stages (A, B, C, and D) were used to describe heart failure progression. This study was aimed to explore plasma metabolomic and lipidomic profiles in different HF stages to identify potential biomarkers. Metabolomics and lipidomics were performed using plasma of heart failure patients at stages A (n?=?49), B (n?=?61), and C+D (n?=?26). Analysis of Variance (ANOVA) was used for screening dysregulated molecules. Bioinformatics was used to retrieve perturbed metabolic pathways. Univariate and multivariate receiver operating characteristic curve (ROC) analyses were used for potential biomarker screening. Stage A showed significant difference to other stages, and 142 dysregulated lipids and 134 dysregulated metabolites were found belonging to several metabolic pathways. Several marker panels were proposed for the diagnosis of heart failure stage A versus stage B-D. Several molecules, including lysophosphatidylcholine 18:2, cholesteryl ester 18:1, alanine, choline, and Fructose, were found correlated with B-type natriuretic peptide or left ventricular ejection fractions. In summary, using untargeted metabolomic and lipidomic profiling, several dysregulated small molecules were successfully identified between HF stages A and B-D. These molecules would provide valuable information for further pathological researches and biomarker development.

     

Elevation of B-type natriuretic peptide is a sensitive marker of left ventricular diastolic dysfunction in patients with maintenance haemodialysis

Objective: To determine the clinical value of B-type natriuretic peptide (BNP) in diagnosing left ventricular diastolic dysfunction (LVDD) associated with maintenance haemodialysis (MHD) population.

Methods: Plasma BNP was determined in 59 MHD patients with normal ejection fraction. The ratio of early to late annular velocity (E’/A’) was determined by tissue Doppler imaging as a parameter of diastolic function.

Results: LVDD occurred in 66% of the patients. Receiver-operating characteristic curve analyses identified a cut-off of 353.6 pg ml^?1 as the one with the highest sensitivity and specificity for detecting LVDD.

Conclusions: Plasma BNP may serve as a potential biomarker in diagnosing LVDD in MHD patients with normal systolic function.     

The GALA study: relationship between galectin-3 serum levels and short- and long-term outcomes of patients with acute heart failure

Objective: We tested the hypothesis that early measurement of galectin-3 at the emergency department (ED) during an episode of acute heart failure (AHF) allows predicting short- and long-term outcomes.

Methods: We performed an exploratory study including 115 patients consecutively diagnosed with AHF in a single ED. Clinical and analytical variables were recorded. The primary endpoint was 30-day all-cause mortality, and secondary endpoints were 30-day composite outcome (death, rehospitalization or ED reconsultation, whichever first) and 1-year mortality.

Results: Seven patients (6.1%) died within 30?days and 43 (37.4%) within 1?year. The 30-day composite endpoint was observed in 21.1% of patients. Galectin-3 was correlated with NT-proBNP and the glomerular filtration rate but not with age and s-cTnI. Measured at time of ED arrival, galectin-3 showed good discriminatory capacity for 30-day mortality (AUC ROC: 0.732; 95% CI 0.512–0.953; p?=?0.041) but not for 1-year mortality (0.521; 0.408–0.633; p?=?0.722). Patients with galectin-3 concentrations?>42?μg/L had an OR?=?7.67(95%CI?=?1.57-37.53; p?=?0.012) for 30-day mortality. Conversely, NT-proBNP only showed predictive capacity for 1-year mortality (0.642; 0.537–0.748; p?=?0.014). Patients with NT-proBNP concentrations?>5400?ng/L had an OR?=?4.34 (95%CI?=?1.93-9.77; p?<?0.001) for 1-year mortality. These increased short- (galectin-3) and long-term (NT-proBNP) risks remained significant after adjustment for age or renal function. s-cTnI failed in both short- and long term death prediction. No biomarker predicted the short-term composite endpoint.

Conclusion: These results suggest that galectin-3 could help to monitor the risk of short-term mortality in unselected patients with AHF attended in the ED.     

The role of iNOS-derived NO in the antihypertrophic actions of B-type natriuretic peptide in neonatal rat cardiomyocytes

In the infarcted rat heart, the increase of NO occurs in the hypertrophied myocardium of non-infarcted areas and its antihypertrophic efficacy has been well established. As another endogenous regulator and the reliable index of heart pathology, B-type natriuretic peptide also exhibits the antihypertrophic properties in many tissues by elevating intracellular cGMP. Several studies indicate that natriuretic peptides family may exert some actions in part via a nitric oxide pathway following receptor-mediated stimulation of iNOS. Therefore, it raises our great interest to ask what role NO plays in the antihypertrophic actions of B-type natriuretic peptide in cardiomyocytes. Incubation of cardiomyocytes under mild hypoxia for 12 h caused a significant increase in cellular protein content, protein synthesis and cell surface sizes. This growth stimulation was suppressed by exogenous B-type natriuretic peptide in a concentration dependent manner. Furthermore, the generation of intracellular cGMP, the upregulation of iNOS mRNA expression, the increase of iNOS activity and subsequent nitrite generation in hypertrophic cardiomyocytes was also increased by B-type natriuretic peptide. AG, a selective iNOS inhibitor, inhibited the upregulation of iNOS expression and the increase of iNOS activity by the combination of B-type natriuretic peptide/mild hypoxia or by the combination of 8-bromo-cGMP/mild hypoxia. Rp-8-br-cGMP, cGMP dependent protein kinase inhibitor, attenuated the actions of B-type natriuretic peptide and 8-bromo-cGMP which increases intracellular cGMP independent of B-type natriuretic peptide. In conclusion, our present data suggest that B-type natriuretic peptide exerted the antihypertrophic effects in cardiomyocytes, which was partially attributed to induction of iNOS-derived NO by cGMP pathway.     

Biomarkers and diagnostics in heart failure

Heart failure (HF) biomarkers have dramatically impacted the way HF patients are evaluated and managed. B-type natriuretic peptide (BNP) and N-terminal proBNP (NT-proBNP) are the gold standard biomarkers in determining the diagnosis and prognosis of HF, and studies on natriuretic peptide-guided HF management look promising. An array of additional biomarkers has emerged, each reflecting different pathophysiological processes in the development and progression of HF: myocardial insult, inflammation and remodeling. Novel biomarkers, such as mid-regional pro atrial natriuretic peptide (MR-proANP), mid-regional pro adrenomedullin (MR-proADM), highly sensitive troponins, soluble ST2 (sST2), growth differentiation factor (GDF)-15 and Galectin-3, show potential in determining prognosis beyond the established natriuretic peptides, but their role in the clinical care of the patient is still partially defined and more studies are needed. This article is part of a Special Issue entitled: Heart failure pathogenesis and emerging diagnostic and therapeutic interventions.     

Designer natriuretic peptides: a vision for the future of heart failure therapeutics

Despite recent pharmacological advances in heart failure therapy, mortality from acute decompensated heart failure remains high. Conventional therapies are often insufficient to address the complex interplay between structural, functional, neurohumoral, and renal mechanisms involved in the heart failure syndrome. The natriuretic peptide system, however, offers a unique pleiotropic strategy which could bridge this gap in heart failure therapy. Exogenous administration of native A-type and B-type natriuretic peptides has been met with both success and limitations, and despite the limitations, remains a worthwhile endeavor. Alternatively, synthetic modification to create "designer" chimeric peptides holds the possibility to extend both the application and therapeutic benefits possible with a natriuretic peptide based approach. Herein we describe the development of natriuretic peptide based heart failure therapies, including the design, rationale, and preliminary studies of the novel chimeric peptides CD-NP and CU-NP.     

Impact of glomerular filtration rate on urinary BNP and NT-proBNP levels in heart failure

B-type natriuretic peptide (BNP) and its inactive amino-terminal fragment (NT-proBNP) are diagnostic tools for heart failure (HF), but less is understood regarding the effects of renal function on their urinary concentrations. The objective was to analyze the influence of renal function, as estimated glomerular filtration rate (eGFR), on BNP and NT-proBNP concentrations in 90 HF outpatients (65 ± 12 years; 73% men), grouped according to eGFR below or above 60 mL/min. Patients with worse eGFR had higher serum NT-proBNP (p < 0.01) and BNP (p < 0.01) than patients with higher eGFR: NT-proBNP, but urinary levels did not reach statistical differences. In addition, a direct significant correlation between filtered load of serum NT-proBNP or BNP with their concentrations in urine was found in patients with eGFR above 60 mL/min (r = 0.66, p < 0.001 and r = 0.338, p < 0.05) and below 60 mL/min (r = 0.63, p < 0.001 and r = 0.406, p < 0.01). However, after normalizing urinary natriuretic peptide concentrations by their filtered load, we obtained a significant inverse and exponential relation in patients with worse renal function for NT-proBNP and BNP (r = -0.87, p = 0.001; and r = -0.71, p < 0.001, respectively) and in patients with eGFR>60 mL/min (r = -0.84, p < 0.001; and r = -0.72, p < 0.001, respectively). In conclusion, similar urinary NT-proBNP and BNP excretion was obtained in patients with high or low eGFR. Furthermore, despite the direct correlation between filtered load of serum natriuretic peptides with their urinary levels, an inverse an exponential relationship was obtained after normalizing urinary concentrations. Therefore, glomerular filtration does not seem to be the major determinant of both urinary peptide concentrations.     

Usefulness of parathyroid hormone as a predictor of heart failure with preserved ejection fraction

Objective: To investigate the relation between parathyroid hormone (PTH) and heart failure with preserved ejection fraction (HF-PEF) in outpatients.

Methods: One hundred consecutive patients who had preserved left ventricular (LV) ejection fraction and heart failure (HF) symptoms, were enrolled. Echocardiography, assessing the diastolic functions was performed. Blood samples were collected for intact PTH and brain natriuretic peptide (BNP).

Results: Significant correlations between PTH level and predictors of advanced HF-PEF were found (p < 0.05). PTH level and left atrium diameter were found to be independent predictors of DHF.

Conclusion: Measurement of serum PTH provides complementary information for the diagnosis and prognosis of HF-PEF.     

The endocrine heart and natriuretic peptides: histochemistry, cell biology, and functional aspects of the renal urodilatin system

 This review focuses on some selected aspects of the endocrine heart and natriuretic peptides. The endocrine heart is composed of specific myoendocrine cells of the cardiac atria. The myoendocrine cells synthesize and secrete the natriuretic peptide hormones which exhibit natriuretic, diuretic, and vasorelaxant properties. Immunohistochemical analyses show that natriuretic peptides of the A-type and B-type are localized not only in the specific granules of these myoendocrine cells but also in many other organs including the brain, adrenal medulla, and kidney. Also, their receptors are detected in many organs showing the multiple functions of these regulatory peptides. Of the members of the natriuretic peptide family, ANP (ANP for atrial natriuretic peptide; also denominated cardiodilatin, CDD), brain natriuretic peptide (BNP), C-type natriuretic peptide (CNP), and the A-type, including its renal form, urodilatin, are emphasized in this review. Urodilatin is localized in the kidney, differentially processed, and secreted into the urine. The intrarenal synthesis and secretion is the basis for a paracrine system regulating water and sodium reabsorption at the level of the collecting duct. CDD/ANP-1-126, cleaved from a precursor of 126 amino acids in the heart to a 28-amino acid-containing circulating molecular form (CDD/ANP-99-126), and urodilatin (CDD/ANP-95-126) share similar biochemical features and biological functions, but urodilatin may be more involved in the regulation of body fluid volume and water–electrolyte excretion, while circulating CDD/ANP-99-126 is responsible for blood pressure regulation. The physiological and pharmacological properties of these peptides have great clinical impact, and as a consequence urodilatin is involved in drug development for the treatment of acute renal failure, cardiomyopathia, and acute asthma. Accepted: 8 July 1998     

Usefulness of serum neopterin levels in acute decompensated heart failure to predict renal dysfunction

Context: Neopterin serum concentration increases in the presence of renal dysfunction.

Objective: We sought to determine the relationship between admission serum neopterin levels and worsening renal function (WRF) in patients with heart failure (HF).

Methods: We prospectively measured serum neopterin levels in patients with HF and the patients were subdivided into two groups: with and without WRF during hospital admission.

Results: Logistic regression analysis showed that high serum neopterin levels at admission were associated with a greater likelihood of developing WRF.

Conclusions: Patients admitted to hospital with HF, elevated serum neopterin levels are associated with an increased risk of developing WRF.     

ANP and CNP activate CFTR expressed in Xenopus laevis oocytes by direct activation of PKA

Abstract

Context: Acting through different receptors, natriuretic peptides (atrial natriuretic peptide [ANP], brain type natriuretic peptide [BNP] and C-type natriuretic peptide [CNP]) increase intracellular cGMP, which then stimulates different pathways that activate fluid secretion. Objective: We used two-electrode voltage clamping to define the dominant pathway that is employed when natriuretic peptides activate cystic fibrosis transmembrane conductance regulator (CFTR) in the Xenopus oocyte expression system. Natriuretic peptides could activate CFTR by 1) cGMP cross-activation of protein kinase A (PKA), 2) cGMP activation of cGMP-dependent protein kinase II, 3) cGMP inhibition of phosphodiesterase type III (PDE3), or 4) direct activation of CFTR. Materials and Methods: cRNA-microinjected Xenopus laevis oocytes were perfused with diverse compounds that examined these pathways of natriuretic peptide signaling. Results and Discussion: ANP stimulated the shark CFTR (sCFTR)-mediated chloride conductance and this activation was inhibited by H-89, a specific inhibitor of PKA. After co-expression of the CNP receptor (NPR-B), sCFTR became stimulatable by CNP and was similarly inhibited by H-89, pointing to cross-activation of PKA. 8-pCPT-cGMP, a relatively cGKII-selective cGMP, failed to stimulate sCFTR. Another membrane-permeable and non-hydrolyzable analog of cGMP, 8-Br-cGMP, stimulated CFTR only at millimolar concentrations, consistent with cross-activation of PKA. The PDE inhibitors EHNA, rolipram, cilostamide, and amrinone did not significantly increase chloride conductance, arguing against a significant role for PDE2, PDE3 and PDE4 signaling in the oocyte. Sildenafil, a PDE5 inhibitor, caused a partial activation of sCFTR channels and this effect was again inhibited by H-89. Conclusion: From these experiments we conclude that in the Xenopus oocyte system, natriuretic peptides, 8-Br-cGMP, and PDE5 inhibitors activate CFTR by cross-activation of PKA.     

Relationship between Bone Mineral Density and Serum Osteoprotegerin in Patients with Chronic Heart Failure

Purpose

Heart failure (HF) had been reported with increased risk of hip fractures. However, the relationship between circulating biomarkers and bone mineral density (BMD) in chronic HF remained unclear.

Methods

This is a cross-sectional study which recruited stable chronic HF from registry of the Heart Failure Center of National Taiwan University Hospital. Patients underwent dual-energy x-ray absorptiometry (DEXA) measurements at hip and lumbar spines and biochemical assessments including B-type natriuretic peptide (BNP-32), myostatin, follistatin and osteoprotegerin (OPG).

Results

A total of 115 stable chronic HF individuals with left ventricular ejection fraction (EF) <45% (74% of male, mean age at 59) were recruited with 24 patients in NYHA class I, 73 patients in NYHA class II and 18 patients in NYHA class III. Results of BMD showed that Z scores of hip in NYHA III group (−0.12±1.15) was significantly lower than who were NYHA II (0.58±1.04). Serum OPG was significantly higher in subjects of NYHA III (9.3±4.6 pmol/l) than NYHA II (7.4±2.8 pmol/l) or NYHA I (6.8±3.6 pmol/l) groups. There’s a significant negative association between log transformed serum OPG and trochanteric BMD (R = −0.299, P = 0.001), which remained significant after multivariate analysis.

Conclusions

Our study demonstrated an inverse association between serum OPG and trochanteric BMD in patients with HF. OPG may be a predictor of BMD and an alternative to DEXA for identifying at risk HF patients for osteoporosis.     

Association of galectin-3 with changes in left ventricular function in recent-onset dilated cardiomyopathy

Abstract

Background: The course of newly diagnosed dilated cardiomyopathy (DCM) varies from persistent reduction of left ventricular ejection fraction (LVEF) to recovery or even worsening. The aim of the present study was to examine the prognostic value of selected biomarkers with regard to changes in LVEF.

Methods: Main inclusion criterion was LVEF ≤45% with exclusion of coronary artery or valvular heart disease. The primary endpoint was LVEF ≤35% in the follow-up echocardiogram. Galectin-3, N-terminal prohormone of brain natriuretic peptide (NT-proBNP) and C-reactive protein (CRP) were related to the endpoint.

Results: Data from 80 DCM patients (55 male, mean age 53 years) were analyzed. Median LVEF was 25% (IQR 25–30). The endpoint was met for 24 patients (30%). These had higher baseline levels of galectin-3 (median 20.3?ng/mL [IQR 14.3–26.9] vs. 14.7?ng/mL [IQR 10.9–17.7], p?=?0.007) and NT-proBNP (3089?pg/mL [IQR 1731–6694] vs. 1498?pg/mL [IQR 775–3890]; p?=?0.004) in univariate Cox regression analysis. ROC analysis revealed that CRP (median 0.4?mg/dL [IQR 0.2–1.2]) was also related to the endpoint (p?=?0.043).

Conclusion: Higher levels of galectin-3, NT-proBNP, and CRP were associated with LVEF ≤35% in our cohort. An approach utilizing a combination of biomarkers for patient management should be assessed in further studies.     

Combined Biomarker Analysis for Risk of Acute Kidney Injury in Patients with ST-Segment Elevation Myocardial Infarction

Background

Acute kidney injury (AKI) complicating ST-segment elevation myocardial infarction (STEMI) increases subsequent morbidity and mortality. We combined the biomarkers of heart failure (HF; B-type natriuretic peptide [BNP] and soluble ST2 [sST2]) and renal injury (NGAL [neutrophil gelatinase-associated lipocalin] and cystatin C) in predicting the development of AKI in patients with STEMI undergoing primary percutaneous coronary intervention (PCI).

Methods and Results

From March 2010 to September 2013, 189 STEMI patients were sequentially enrolled and serum samples were collected at presentation for BNP, sST2, NGAL and cystatin C analysis. 37 patients (19.6%) developed AKI of varying severity within 48 hours of presentation. Univariate analysis showed age, Killip class ≥2, hypertension, white blood cell counts, hemoglobin, estimated glomerular filtration rate, blood urea nitrogen, creatinine, and all the four biomarkers were predictive of AKI. Serum levels of the biomarkers were correlated with risk of AKI and the Acute Kidney Injury Network (AKIN) stage and all significantly discriminated AKI (area under the receiver operating characteristic [ROC] curve: BNP: 0.86, sST2: 0.74, NGAL: 0.75, cystatin C: 0.73; all P < 0.05). Elevation of ≥2 of the biomarkers higher than the cutoff values derived from the ROC analysis improved AKI risk stratification, regardless of the creatine level (creatinine < 1.24 mg/dL: odds ratio [OR] 11.25, 95% confidence interval [CI] 1.63-77.92, P = 0.014; creatinine ≥ 1.24: OR 15.0, 95% CI 1.23-183.6, P = 0.034).

Conclusions

In this study of STEMI patients undergoing primary PCI, the biomarkers of heart failure (BNP and sST2) and renal injury (NGAL and cystatin C) at presentation were predictive of AKI. High serum levels of the biomarkers were associated with an elevated risk and more advanced stage of AKI. Regardless of the creatinine level, elevation of ≥2 of the biomarkers higher than the cutoff values indicated a further rise in AKI risk. Combined biomarker approach may assist in risk stratification of AKI in patients with STEMI.     

Natriuretic peptides in fish physiology

Natriuretic peptides exist in the fishes as a family of structurally-related isohormones including atrial natriuretic peptide (ANP), C-type natriuretic peptide (CNP) and ventricular natriuretic peptide (VNP); to date, brain natriuretic peptide (or B-type natriuretic peptide, BNP) has not been definitively identified in the fishes. Based on nucleotide and amino acid sequence similarity, the natriuretic peptide family of isohormones may have evolved from a neuromodulatory, CNP-like brain peptide. The primary sites of synthesis for the circulating hormones are the heart and brain; additional extracardiac and extracranial sites, including the intestine, synthesize and release natriuretic peptides locally for paracrine regulation of various physiological functions. Membrane-bound, guanylyl cyclase-coupled natriuretic peptide receptors (A- and B-types) are generally implicated in mediating natriuretic peptide effects via the production of cyclic GMP as the intracellular messenger. C- and D-type natriuretic peptide receptors lacking the guanylyl cyclase domain may influence target cell function through G(i) protein-coupled inhibition of membrane adenylyl cyclase activity, and they likely also act as clearance receptors for circulating hormone. In the few systems examined using homologous or piscine reagents, differential receptor binding and tissue responsiveness to specific natriuretic peptide isohormones is demonstrated. Similar to their acute physiological effects in mammals, natriuretic peptides are vasorelaxant in all fishes examined. In contrast to mammals, where natriuretic peptides act through natriuresis and diuresis to bring about long-term reductions in blood volume and blood pressure, in fishes the primary action appears to be the extrusion of excess salt at the gills and rectal gland, and the limiting of drinking-coupled salt uptake by the alimentary system. In teleosts, both hypernatremia and hypervolemia are effective stimuli for cardiac secretion of natriuretic peptides; in the elasmobranchs, hypervolemia is the predominant physiological stimulus for secretion. Natriuretic peptides may be seawater-adapting hormones with appropriate target organs including the gills, rectal gland, kidney, and intestine, with each regulated via, predominantly, either A- or B-type (or C- or D-type?) natriuretic peptide receptors. Natriuretic peptides act both directly on ion-transporting cells of osmoregulatory tissues, and indirectly through increased vascular flow to osmoregulatory tissues, through inhibition of drinking, and through effects on other endocrine systems.     

rhBNP 在心力衰竭合并肾功能不全中的应用前景

心力衰竭同时合并肾功能不全或肾功能恶化,也称为心肾综合征,是临床心血管疾病的终末阶段,患者的死亡率及再住院率较高。重组人脑利钠肽是利用重组DNA技术制成的人脑利钠肽,与内源性脑利钠肽具有相同的药理作用:扩张血管,降低右房压力及肺毛细血管楔压,减轻心脏负荷,可以选择性扩张冠状动脉,增加冠状动脉的血流量;通过激活心肌细胞内c GMP依赖的蛋白激酶PKG-1,产生细胞应激性保护,降低心肌耗氧量;抑制RAAS及SNS,抑制反射性心动过速和血管收缩,无正性肌力作用和正性心率作用,抑制心脏重塑。重组人脑利钠肽作用于肾脏可以改善肾脏血流灌注,提高肾小球滤过率。虽然重组人脑利钠肽治疗心力衰竭取得了很好地效果,但其对心力衰竭患者肾功能的影响仍存在争议。重组人脑利钠肽具有多重活性且不良反应少,已被许多专家视为很有应用前景的新药。     

Functional expression of recombinant anti-BNP scFv in methylotrophic yeast <Emphasis Type="Italic">Pichia pastoris</Emphasis> and application as a recognition molecule in electrochemical sensors

Recent studies have revealed the potential of B-type natriuretic peptide (BNP) as a good prognostic marker for patients with heart failure. Antibodies against BNP are expected to be usefully employed in the diagnosis of heart failures. We established a more efficient method to produce functional anti-BNP, single chain variable fragment (scFv) using a eukaryotic expression system of Pichia pastoris. Although analysis of the N-terminal (NT) sequence of the expressed anti-BNP scFv indicated that the two Ste13 sites of the secreted anti-BNP scFv were not cleaved, the specificity of anti-BNP scFv was not affected significantly. The binding activity of anti-BNP scFv against other antigens, against four other antigens, NT probrain peptide (NT-pro BNP), atrial natriuretic peptide (ANP), carcinoembryonic antigen (CEA) and human serum albumin (HSA), was only one thousandth that of the original BNP antigen, which clearly demonstrated the specific binding of recombinant scFv toward BNP. The anti-BNP, scFv-based, electrochemical immunoassay exhibited excellent analytical performance with a detection limit of 1 fg/ml and a wide linear detection range from 1 to 10,000 fg/ml. The optimum culture conditions to obtain the maximum concentration of recombinant scFv were a pH range of 5.0–7.0 and an incubation temperature of 20°C. This anti-BNP scFv expressed in P. pastoris has the potential for promising applications in the diagnosis of heart failure.     

Patients with heart failure with preserved ejection fraction and low levels of natriuretic peptides

Aims

Heart failure with preserved ejection fraction (HFpEF) is common and its management remains difficult. B-type natriuretic peptide (BNP) levels are used to diagnose heart failure, and as an entry criterion for inclusion into trials. We investigated a population of HFpEF patients who had been randomised into a study based on clinical parameters, and compared those with low BNP levels to those with elevated BNP levels.

Methods

We examined patients who had been enrolled in the Coordinating study evaluating Outcomes of Advising and Counselling in Heart Failure (COACH), with preserved left ventricular ejection fraction (LVEF ≥ 40 %), and compared those with low BNP (< 100 pg/ml; n = 30) to those with elevated BNP (≥ 100 pg/ml; n = 127). Baseline characteristics, comorbidities, biomarkers, quality of life, and outcome parameters (hospitalisations and death) were compared between the groups. To validate our findings, we repeated all analyses for NT-proBNP (< 300 pg/ml and ≥ 300 pg/ml).

Results

Patients were similar with regard to most clinical characteristics (including age, sex, and LVEF), biomarkers, and comorbidities. In contrast, patients with a low BNP had higher body mass index levels (31 kg/m² vs. 27 kg/m²; p < 0.01) and lower cardiac troponin I (9 pg/ml vs. 15 pg/ml; p = 0.02). In addition, these patients were less frequently prescribed diuretics and beta-blockers. No differences in quality of life, heart failure related symptoms and the primary and secondary outcomes were observed between these groups. These observations were confirmed for NT-proBNP.

Conclusion

Among the patients with clinically diagnosed HFpEF, those with low BNP are strikingly similar to those with elevated BNP levels, except for BMI, which was significantly higher in these patients.

Electronic supplementary material

The online version of this article (doi:10.1007/s12471-016-0816-8) contains supplementary material, which is available to authorized users.