Form Of Brain Natriuretic Peptide Research Articles

Continuous monitoring of heart failure biomarker using a sensitive graphene-based electrical sensor

Abstract Heart Failure (HF) is a complex condition that imposes significant burdens on both patients and healthcare systems. The economic impact of HF therapy and management is substantial, underscoring the urgency for proactive measures to mitigate its development. Regular assessments play a pivotal role in identifying individuals at risk and initiating timely interventions to prevent or delay HF progression [1, 2]. NT-proBNP, an amine-terminated form of brain natriuretic peptide, emerges as a promising biomarker in the realm of chronic HF diagnosis, prognosis, and risk assessment [3]. Its utility lies in providing valuable insights into disease progression and prognosis. In recent years, biosensors based on Field Effect Transistors with Graphene (Gr) gate (GFET) have garnered attention for their rapid response, sensitivity, and on-chip integration [4]. Here, we present a sensitive miniaturized GFET sensor for continuous NT-proBNP measurement. The sensor is an array of GFET devices with sensing gates of a monolayer Gr decorated with aptamers as catch probes. Averaging over similar devices in an array approach ensures measurement consistency throughout the experiment. Moreover, the significant challenge posed by the Debye length in FET biosensors is effectively addressed through the functionalization with short folding aptamers [4]. The sensor is built based on a chip comprising an array of 28 individual micro GFETs (Fig. 1a). For the functionalization of Gr gates, we utilized 1-pyrene butyric acid N-hydroxysuccinimide ester as a linker between the aptamer probes and the Gr surface. Subsequently, the Gr surface was incubated with an amine-terminated aptamer solution (Fig. 1c). A schematic diagram of the sensory chip having a droplet of the sample is shown in Fig. 1b. To quantify NT-proBNP levels an 8µL droplet of the buffer solution containing a specific NT-proBNP concentration was deposited onto the sensor. The drain current (IDS) served as the sensor signal for each target concentration (Figs. 2a and 2b). The sensor signal decreased with increasing target concentration, while negligible response was observed when injecting blank buffers. This phenomenon can be attributed to the folding of aptamers upon binding to their target. Also, continuous measurement was conducted at a fixed gate voltage of 0.9V, recording the drain current while the target concentration gradually increased in the sample droplet. This process revealed a decrease in sensor current as we expected (Fig. 2c). The sensor exhibits remarkably low detection limits of 50 pg/mL and a linear range from 100 pg/mL to 10 ng/mL, which are highly conducive for early HF diagnosis and aligning well with reported NT-proBNP levels in patient biofluid [5]. The proposed sensor holds promise as a wearable device for continuous monitoring of high-risk patients. Additionally, this technology shows potential as a detection tool for acute heart failure in hospitalized patients.Sensor viewSensor responses

Abstract 101: Serum Pro Brain Natriuretic Peptide (pro BNP) Levels In Children With Kawasaki Disease

Introduction: Brain natriuretic peptide (BNP) is a useful biomarker for diagnosing heart failure in adults and children. ProBNP, the precursor form of BNP has been shown to predict myocardial involvement in acute Kawasaki disease (KD) especially in cases of incomplete KD. As the phenotype of KD in North India is different from that in Japan and North America, this study was carried out to validate the utility of proBNP in North Indian children with KD. Objectives: To assay the levels of proBNP in North Indian children with KD. Methodology: Serum pro brain natriuretic peptide (pro BNP and NT-proBNP) levels were estimated in 25 children with Kawasaki disease, both during acute phase and later in convalescence. The levels were similarly assayed in an equal number of age and sex matched controls. The proBNP levels were estimated by an enzyme linked immunosorbent assay (ELISA) using the RayBio Human proBNP ELISA kit which detects both pro BNP and NT-pro BNP. Results: Pro BNP levels were significantly elevated in children during acute phase of KD (4259±8015 pg/ml) when compared to febrile controls (407±542pg/ml) or to children in convalescent phase of KD (509±1066 pg/ml). Pro BNP levels were also higher in children with coronary abnormalities in acute phase. Conclusions: In our experience, pro BNP is a useful biomarker for KD especially with regard to myocardial involvement. ProBNP level is markedly elevated during the acute phase in all children with KD. In children with persistent coronary artery abnormalities, the proBNP level remains elevated even during convalescence. Future impact: ProBNP may be useful marker for children with incomplete forms of KD

NT-Pro Brain Natriuretic Peptide: Is it a New Indicator of Brain Oedema?

Objective To assess the role of the N-terminal prohormone form of brain natriuretic peptide (NT-proBNP) in patients with acute brain oedema. Methods This is a case control study. Twenty-two patients with acute brain oedema evidenced by computed tomography (CT) were recruited and compared to a control group of 30 healthy adult volunteers. Levels of NT-proBNP were measured in all patients at hospital admission and on the 12th and 24th hours after admission; as well as in a control group of 30 healthy blood donors. Results Twenty-two patients with brain oedema and 30 controls were included. There were significant differences between the brain oedema group and the control group on the NT-proBNP levels at admission time, on 12th or 24th hours after admission. There was no significant difference in NT-proBNP levels at admission time with the severity of brain oedema evidenced by CT. When we considered the relationship between mannitol usage and NT-proBNP levels, we found a significant difference between brain oedema severity and NT-proBNP level according to brain oedema severity after anti-oedema treatment, for 12th and 24th hours NT-proBNP levels. Conclusions There is a possible association between brain oedema and elevated serum NT-proBNP levels. (Hong Kong j.emerg.med. 2014;21:167-171)

Does nesiritide reduce mortality and readmission in decompensated heart failure?

Heart failure (HF) is characterized by insufficient cardiac output to supply adequate perfusion to the peripheral de-mands. When decompensated, it can cause various sys-temic effects, depending on the type of presentation. The patient may have only a low cardiac output, or may have a large pulmonary vascular congestion, causing acute pul-monary edema and clinically important dyspnea.Nesiritide is a recombinant form of brain natriuretic peptide (BNP), secreted when the walls of the heart’s ven-tricles are dilated, and its use was approved in 2001 by the FDA for the treatment of decompensated HF. It has va-sodilatory properties, causing reduced pre- and afterload, decreased pulmonary capillary pressure, and increased cardiac output without inotropic effects

Increased Expression of Growth Differentiation Factor-15 in Systemic Sclerosis-Associated Pulmonary Arterial Hypertension

Growth differentiation factor (GDF)-15 is a secreted member of the transforming growth factor-β cytokine superfamily. GDF-15 levels are elevated in the serum of patients with cardiovascular diseases. We hypothesized that GDF-15 levels would also be increased in the plasma and lung tissue of patients with systemic sclerosis-associated pulmonary arterial hypertension (SSc-PAH). GDF-15 levels were measured in plasma in subjects with SSc-PAH (n = 30) and compared with subjects with systemic sclerosis (SSc) without pulmonary arterial hypertension (PAH) (n = 24). Patients with idiopathic PAH (IPAH) (n = 44) and normal individuals (n = 13) served as control subjects. Immunohistochemistry and immunofluorescence assay identified GDF-15 protein in lung tissue from patients with SSc-PAH and IPAH. Patients with SSc-PAH had significantly higher mean circulating levels of GDF-15 in plasma compared with patients with SSc without PAH (422.3 ± 369.5 pg/mL vs 108.1 ± 192.8 pg/mL, P = .004). GDF-15 levels correlated positively with estimated right ventricular systolic pressure on echocardiogram and plasma levels of the amino terminal propeptide form of brain natriuretic peptide. There was an inverse correlation between circulating GDF-15 and diffusing capacity of the lung for carbon monoxide (Dlco) and a positive correlation with the FVC to Dlco ratio on pulmonary function test. GDF-15 levels > 125 pg/mL were associated with reduced survival. GDF-15 protein expression was increased in lung tissue from patients with SSc-PAH. GDF-15 may be a useful biomarker in PAH associated with SSc. Its presence in lung tissue may suggest a role in the pathology of the disease.

Molecular form of Brain Natriuretic Peptide (BNP) Secreted from Cultured Atrial and Ventricular Myocytes and its Processing System

Molecular form of Brain Natriuretic Peptide (BNP) Secreted from Cultured Atrial and Ventricular Myocytes and its Processing System

Diversity of molecular forms of plasma brain natriuretic peptide in heart failure—different proBNP-108 to BNP-32 ratios in atrial and ventricular overload

ObjectiveRecent studies have shown that plasma levels of brain natriuretic peptide (BNP)-32 and proBNP-108 are increased in heart failure (HF) and that the BNP-32 assay kit in current clinical use...

CATALYTIC RECEPTORS

CATALYTIC RECEPTORS

Unraveling the Complexity of Circulating Forms of Brain Natriuretic Peptide

Determining the circulating form of a biomarker is critical for the development of a highly sensitive and specific immunoassay. The hormone brain natriuretic peptide (BNP) is produced in the atria as a preprohormone, and the cleavage of its signal sequence produces the circulating prohormone proBNP (amino acid residues 1–108, human sequence). The prohormone is subsequently cut to yield a 76-amino acid N-terminal (NT) fragment (NT-proBNP) and the 33-amino acid active hormone BNP (comprising residues 77–108 of proBNP). The 2 commercially available immunoassays detect either the circulating NT fragment or BNP and, potentially, could detect proBNP. However, whether these assays detect all possible circulating forms of BNP remains unclear. The potential circulating forms of BNP have different intrinsic physical characteristics that can dictate antigenicity, extent of nonspecific binding during isolation, endogenous clearance kinetics, circulating half-life, and/or affinity for other proteins including cellular receptors and putative serum/plasma carrier proteins. Consequently, characterization of the physical status of each circulating form of BNP is key to assay development. It is critical to determine whether the circulating BNP forms have posttranslational modifications (PTM), such as phosphorylation or N- and O-linked glycosylation, and/or bind to other protein(s). In a recent issue of Clinical Chemistry , an article by Seferian et al. (1) described 2 approaches to shedding light on the circulating forms of BNP. The 2 strategies examined differences in ( a ) antigenicity, ( b ) antibody binding, and ( c ) the theoretical and observed MWs of the unmodified recombinant form and the circulating endogenous form(s). The data presented indicated that the chemistry of circulating BNP is complex. This complexity needs to be taken into account during immunoassay development. Is there a potential PTM? Seferian et al. (1) produced a large number of peptides and fragments of BNP (pro, NT-pro, and BNP) …

Lack of activation of molecular forms of the BNP system in human grade 1 hypertension and relationship to cardiac hypertrophy

We evaluated relationships among two circulating molecular forms of brain natriuretic peptide (BNP32 and NT-proBNP), severity of hypertension (HTN), and cardiac hypertrophy in subjects with mild, moderate, and severe HTN. We prospectively studied 78 patients (43 males; mean age 51.4 +/- 11 yr) with essential HTN and 28 age- and sex-matched controls. BNP32 and NT-proBNP were measured by radioimmunoassay. In grade 1 HTN, BNP32 was not elevated and NT-proBNP was reduced (P = 0.030) compared with controls. However, log-transformed values of BNP32 and NT-proBNP were both increased with severity of HTN from grade 1 to 3 (P <0.0001 and P = 0.003, respectively). By multivariate analysis, log BNP32 was independently predicted by age (beta = 0.210, P = 0.026) and HTN grade (beta = 0.274, P = 0.004), whereas log NT-proBNP was independently predicted by sex (beta = 0.235, P = 0.012) and HTN grade (beta = 0.218, P = 0.0023). Two forms of BNP were measured in normal subjects and patients with essential HTN. In grade 1 HTN, BNP32 was unchanged and NT-proBNP was significantly reduced compared with controls. As severity increased in humans with grade 1 to 3 HTN, both BNP32 and NT-proBNP levels were increased while not being affected by the presence of left ventricular hypertrophy. The lack of activation of BNP32 together with the reduction of NT-proBNP in grade 1 HTN may represent an impaired response of the BNP system in the early phase of HTN. The later activation of both forms of BNP may be a late compensatory effect, because it correlates with severity of HTN rather than cardiac hypertrophy/remodeling.

Prognostic Value of Plasma N-Terminal Pro-Brain Natriuretic Peptide in Patients With Severe Sepsis

Increased plasma levels of atrial natriuretic peptide (ANP) and brain natriuretic peptide (BNP) have been identified as predictors of cardiac dysfunction and prognosis in congestive heart failure and ischemic heart disease. In severe sepsis patients, however, no information is available yet about the prognostic value of natriuretic peptides. Therefore, the aim of the present study was to determine the role of the N-terminal prohormone forms of ANP (NT-proANP) and BNP (NT-proBNP) in the context of outcome of septic patients. Furthermore, the effect of treatment with recombinant human activated protein C [drotrecogin alfa (activated)] on plasma levels of natriuretic peptides in severe sepsis was evaluated. Fifty-seven patients with severe sepsis were included. Levels of NT-proANP and NT-proBNP were measured on the second day of sepsis by ELISA. Septic patients with NT-proBNP levels >1400 pmol/L were 3.9 times more likely (relative risk [RR], 3.9; 95% CI, 1.6 to 9.7) to die from sepsis than patients with lower NT-proBNP values (P<0.01). NT-proANP levels, however, were not predictive of survival in our patient population. A highly significant correlation was found between troponin I levels and plasma concentrations of NT-proBNP in septic patients (r=0.68, P<0.0001). In addition, troponin I significantly accounted for the variation in NT-proBNP levels (P<0.0001), suggesting an important role for NT-proBNP in the context of cardiac injury and dysfunction in septic patients. Twenty-three septic patients who received treatment with drotrecogin alfa (activated) presented with significantly lower concentrations of NT-proANP, NT-proBNP, and troponin I compared with patients not receiving drotrecogin alfa (activated). NT-proBNP may serve as useful laboratory marker to predict survival in patients presenting with severe sepsis.

The natriuretic peptides in cardiovascular medicine

Within the last five years, assay systems for measurement of plasma levels of brain natriuretic peptide (BNP) have been approved as a diagnostic aid for heart failure (HF). Similarly, nesiritide, a recombinant form of human BNP, has been approved for the treatment of acutely decompensated HF. Both BNP as a diagnostic test and a therapeutic modality are rapidly becoming integrated into clinical practice. The purpose of this review is to provide a brief overview of the physiology of the natriuretic peptides relevant to their informed clinical use. The current literature regarding the utility of measuring BNP for the diagnosis and management of HF is reviewed and practical recommendations regarding the interpretation of BNP levels are offered. The clinical literature regarding the use of recombinant BNP for the treatment of HF is reviewed, underscoring current gaps in our knowledge regarding the indications for and benefits of this novel agent.

Natriuretic peptide system: physiology and clinical utility

This review discusses the physiology of natriuretic peptides as a group and brain natriuretic peptide (BNP) in more detail. It will also highlight implications for the use of the natriuretic peptides in the diagnosis and treatment of patients with cardiovascular disease. The heart secretes two major natriuretic peptides: atrial natriuretic peptide (ANP), which is synthesized in the atrial myocardium, and BNP, which is synthesized in the ventricular myocardium. Both ANP and BNP are released in response to atrial and ventricular stretch, respectively, and will cause balanced vasodilation, natriuresis, and inhibition of the sympathetic nervous system and the renin-angiotensin-aldosterone axis. BNP is reported to be the biochemical marker of choice for evaluating the acute risk of patients with cardiovascular disease states ranging from heart failure to myocardial ischemia. Increased blood BNP concentrations are highly predictive of the short- and long-term risk of cardiac death across the entire spectrum of acute coronary syndromes and in patients with decompensated congestive heart failure. Synthetic recombinant human BNP, which mimics the actions of endogenous BNP, has emerged as an important new therapeutic agent in patients with acute heart failure. Current data suggest that single and serial plasma measurement of BNP concentrations is a useful tool in the diagnosis and risk stratification of patients with heart disease. Nesiritide, the human recombinant form of BNP, is a new promising parenteral treatment in decompensated heart failure.

Characterization of molecular forms of probrain natriuretic peptide in human plasma

Background: Measurement of brain natriuretic peptide (BNP) in plasma is useful for the diagnosis and prognosis of heart failure. However, the molecular forms of BNP, especially proBNP in the blood, have been poorly characterized. Methods: To investigate the forms of proBNP in blood, antibodies against four proBNP synthetic peptides (1–13, 22–27, 28–40, and 47–54) were developed and characterized for their reactivity to proBNP by ELISA. Using the antibodies and a monoclonal antibody specific to the carboxyl terminal histidine of BNP, a radioimmunoassay for proBNP was constructed. BNPs in plasma from heart failure patients were analyzed by gel-filtration HPLC followed by immunoassay for BNP and proBNP. Results: Two of four antibodies against proBNP synthetic peptides reacted with both r-proBNP and BNP in plasma from the patients. Gel-filtration HPLC analysis showed two major peaks of immunoreactive BNP (high MW BNP (36 kDa) and low MW BNP (4 kDa)). The immunoassay demonstrated that almost the full-length of proBNP was contained in the high MW BNP fractions. Conclusions: ProBNP was more stable than its mature form of BNP in circulation after secretion, and it suggested the usefulness of proBNP measurement.

Molecular forms of human brain natriuretic peptide in plasma

Background: Brain natriuretic peptide (BNP) is a vasoreactive peptide hormone, which is synthesized and secreted mainly from the heart ventricles. Methods: Molecular forms of immunoreactive human brain natriuretic peptide (BNP) were examined. Chemically synthesized human BNP was added to whole blood samples from a healthy volunteer. The immunoreactive peptide was recovered by immunoaffinity chromatography followed by reversed-phase HPLC (RP-HPLC). Molecular form of immunoreactive BNP in plasma from heart failure patients was also examined. Results: Sequential analysis and amino acid analysis of the peptide revealed that two amino acid residues were deleted from the amino terminus of BNP. When roughly classified according to molecular weight (MW), two forms of BNP (high-MW BNP and low-MW BNP) were observed. The estimated MW of high-MW BNP (36 kDa) was three times that of pro-BNP (12 kDa). Conclusions: Analysis of low-MW BNP by RP-HPLC revealed that a small amount of BNP 1–32 or des-SerPro-BNP (BNP 3–32) was contained in plasma from heart failure patients.

Ovine brain natriuretic peptide in cardiac tissues and plasma: effects of cardiac hypertrophy and heart failure on tissue concentration and molecular forms

Whereas numerous studies have examined the cardiac tissue content and secretion of atrial natriuretic peptide (ANP), the response of brain natriuretic peptide (BNP) in states of experimental cardiac overload is less well documented. Our recent partial cloning of the ovine BNP gene has enabled us to study changes in cardiac tissue concentration, together with tissue and circulating molecular forms of ANP and BNP, in response to cardiac overload induced by rapid ventricular pacing (n = 7) and aortic coarctation (n = 6). In normal sheep, although highest levels of BNP were found in atrial tissue (15-fold those of the ventricle), the BNP/ANP concentration ratio in the ventricles was 10- to 20-fold higher than the ratio calculated for atrial tissue. Compared with normal sheep, significant depletion of both ANP and BNP concentrations within the left ventricle occurred after rapid ventricular pacing. Size exclusion and reverse phase HPLC analysis of atrial and ventricular tissue extracts from normal and overloaded sheep showed a single peak of high molecular weight BNP consistent with the proBNP hormone. In contrast, immunoreactive BNP extracted from plasma drawn from the coronary sinus was all low molecular weight material. Further analysis of plasma BNP using ion exchange HPLC disclosed at least 3 distinct immunoreactive peaks consistent with ovine BNP forms 26-29 amino acid residues in length. These findings show that BNP is stored as the prohormone in sheep cardiac tissues and that complete processing to mature forms occurs at the time of secretion. The capacity to process the prohormone at secretion is not impaired by chronic heart failure.

Immunoreactive brain natriuretic peptide in human adrenal glands and adrenal tumors.

The presence of brain natriuretic peptide (BNP) in tissues of human adrenal glands and adrenal tumors was investigated by radioimmunoassay. Immunoreactive BNP concentrations were 0.203 +/- 0.061 pmol/g wet tissue (mean +/- SEM) in normal parts of adrenal glands (cortex and medulla, N = 8), 0.205 +/- 0.037 pmol/g wet tissue in pheochromocytomas (N = 8), 0.230 +/- 0.062 pmol/g wet tissue in aldosteronomas (N = 11) and 0.180 +/- 0.054 pmol/g wet tissue in adrenocortical adenomas with Cushing's syndrome (N = 4). Sephadex G-50 superfine column chromatography and reverse-phase high-performance liquid chromatography showed that most (> 70%) of the immunoreactive BNP in the normal part of adrenal glands was eluted in the position of human BNP-32. Sephadex G-50 superfine column chromatography of immunoreactive BNP in the pheochromocytoma and aldosteronoma showed four peaks: one in the position of gamma-BNP, one in the position of BNP-32, one between gamma-BNP and BNP-32 and one in the smaller molecular weight region. The present study has shown that immunoreactive BNP is present both in normal human adrenal glands and in adrenal tumors. Multiple molecular forms of BNP were found to be present in the tumor tissues of pheochromocytoma and aldosteronoma.

Concentration and molecular forms of brain natriuretic peptide in rat plasma and spinal cord

To characterize the biological functions of rat brain (B-type) natriuretic peptide (BNP), which has been shown to be present mainly in the heart and only faintly in the spinal cord, the concentration and molecular forms of BNP in plasma and spinal cord were determined. The concentration of immunoreactive (ir-) BNP was 2.00 fmol/ml in normal rat and 13.29 fmol/ml in morphine-treated rat, being respectively about 1 20 and 1 80 those of ir-atrial (A-type) natriuretic peptide (ANP). In morphine-treated rats, ir-BNP was shown to circulate mainly as BNP-45, which is identical to a major storage form found in cardiac atrium. In the spinal cord, BNP was also shown to be present as BNP-45, but its concentration was only 0.057 pmol/g, being about 1 60 that of spinal cord ANP. These results confirm that BNP mainly functions as a circulating hormone in the molecular form of BNP-45. Morphine stimulates secretion of ANP and BNP but by different ratios, suggesting different regulation systems for storage and secretion of ANP and BNP.

Distribution and molecular forms of brain natriuretic peptide in the central nervous system, heart and peripheral tissue of rat

The amino acid sequence of rat brain natriuretic peptide (rBNP) precursor has recently been deduced by the cDNA cloning method (1). In the present study, a radioimmunoassay (RIA) system for rBNP was newly established, and regional distribution of rBNP in the central nervous system, heart and other peripheral tissue of rat was investigated. In heart, especially in cardiac atrium, a high concentration of immunoreactive (ir-) rBNP was detected and identified as rBNP-45 and gamma-rBNP. No significant amount of ir-rBNP was found in other tissues examined including the central nervous system. Especially in brain, no ir-rBNP was detected, while ir-rat atrial natriuretic peptide (rANP) was observed at a relatively high concentration. These results demonstrate a sharp contrast between rat and porcine brains in ir-BNP distribution.

Cloning and sequence analysis of cDNA encoding a precursor for porcine brain natriuretic peptide

Brain natriuretic peptide (BNP) is a new type of natriuretic peptide recently identified in porcine brain. Since the highest concentration of BNP was found in the cardiac atrium, the cDNA library of porcine cardiac atrium was constructed, and the cDNA clone encoding a BNP precursor was isolated and sequenced. The precursor for porcine BNP (porcine prepro-BNP) is 131 amino acids in length, including a 25 residue putative signal peptide at the N-terminus. Porcine BNP structure is located at the C-terminus of the precursor and is directly followed by a termination codon. Based on structural data recently obtained for gamma-BNP (a main storage form of BNP in the heart), prepro-BNP is processed to 106-residue gamma-BNP by removal of the signal peptide in the heart, and to low molecular weight forms, such as BNP-26 and BNP-32, in the brain.