A review on B-type natriuretic peptide monitoring: assays and biosensors

Voluntary wheel running as a promising strategy to promote autonomic resilience to social stress in females: Vagal tone lies at the heart of the matter

Social stress is a major risk factor for comorbid conditions including cardiovascular disease and depression. While women exhibit 2-3× the risk for these stress-related disorders compared to men, the mechanisms underlying heightened stress susceptibility among females remain largely unknown. Due to a lack in understanding of the pathophysiology underlying stress-induced comorbidities among women, there has been a significant challenge in developing effective therapeutics. Recently, a causal role for inflammation has been established in the onset and progression of comorbid cardiovascular disease/depression, with women exhibiting increased sensitivity to stress-induced immune signaling. Importantly, reduced vagal tone is also implicated in stress susceptibility, through a reduction in the vagus nerve's well-recognized anti-inflammatory properties. Thus, examining therapeutic strategies that stabilize vagal tone during stress may shed light on novel targets for promoting stress resilience among women. Recently, accumulating evidence has demonstrated that physical activity exerts cardio- and neuro-protective effects by enhancing vagal tone. Based on this evidence, this mini review provides an overview of comorbid cardiovascular and behavioral dysfunction in females, the role of inflammation in these disorders, how stress may impart its negative effects on the vagus nerve, and how exercise may act as a preventative. Further, we highlight a critical gap in the literature with regard to the study of females in this field. This review also presents novel data that are the first to demonstrate a protective role for voluntary wheel running over vagal tone and biomarkers of cardiac dysfunction in the face of social stress exposure in female rats.

NT-proBNP cardiac value in COVID-19: a focus on the paediatric population

NT-proBNP is a peptide related to brain natriuretic peptide, a cardiac biomarker and a member of the natriuretic family of peptides. NT-proBNP has demonstrated its clinical utility in the assessment of a wide spectrum of cardiac manifestations. It is also considered a more precise diagnostic and prognostic cardiac biomarker than brain natriuretic peptide. With the appearance of the Severe Acute Respiratory Syndrome Coronavirus 2 virus and the subsequent COVID-19 pandemic, diagnosis of heart implications began to pose an increasing struggle for the physician. Echocardiography is considered a central means of evaluating cardiac disorders like heart failure, and it is considered a reliable method. However, other diagnostic methods are currently being explored, one of which involves the assessment of NT-proBNP levels. In the literature that involves the adult population, significant positive correlations were drawn between the levels of NT-proBNP and COVID-19 outcomes such as high severity and fatality. In the paediatric population, however, the literature is scarce, and most of the investigations assess NT-proBNP in the context of Multiple Inflammatory Syndrome in Children, where studies have shown that cohorts with this syndrome had elevated levels of NT-proBNP when compared to non-syndromic cohorts. Thus, more large-scale studies on existing COVID-19 data should be carried out in the paediatric population to further understand the prognostic and diagnostic roles of NT-proBNP.

Predictive biomarkers for the early detection and management of heart failure

Cardiovascular disease (CVD) is a serious public health concern whose incidence has been on a rise and is projected by the World Health Organization to be the leading global cause of mortality by 2030. Heart failure (HF) is a complicated syndrome resulting from various CVDs of heterogeneous etiologies and exhibits varying pathophysiology, including activation of inflammatory signaling cascade, apoptosis, fibrotic pathway, and neuro-humoral system, thereby leading to compromised cardiac function. During this process, several biomolecules involved in the onset and progression of HF are released into circulation. These circulating biomolecules could serve as unique biomarkers for the detection of subclinical changes and can be utilized for monitoring disease severity. Hence, it is imperative to identify these biomarkers to devise an early predictive strategy to stop the deterioration of cardiac function caused by these complex cellular events. Furthermore, measurement of multiple biomarkers allows clinicians to divide HF patients into sub-groups for treatment and management based on early health outcomes. The present article provides a comprehensive overview of current omics platform available for discovering biomarkers for HF management. Some of the existing and novel biomarkers for the early detection of HF with special reference to endothelial biology are also discussed.

Amino acids analysis reveals serum methionine contributes to diagnosis of the Kawasaki disease in mice and children

BACKGROUND

Kawasaki disease (KD) patients often lack early and definitive diagnosis due to insufficient clinical criteria, whereas biomarkers might accelerate the diagnostic process and treatment.

METHODS

The KD mouse models were established and thirteen amino acids were determined. A total of 551 serum samples were collected including KD patients (n = 134), HCs (n = 223) and KD patients after intravascular immunoglobulin therapy (IVIG, n = 194). A paired analysis of pre- and post-IVIG was employed in 10 KD patients.

RESULTS

The pathological alterations of the aorta, myocardial interstitium and coronary artery vessel were observed in KD mice; the serum levels of methionine in KD mice (n = 40) were markedly altered and negatively correlated with the C-reactive protein levels. Consistent with the mouse model, serum methionine were significantly decreased in KD children, with the relative variation ratio of KD with HCs above 30% and AUROC value of 0.845. Serum methionine were correlated with Z-Score and significantly restored to the normal ranges after KD patient IVIG treatment. Another case-control study with 10 KD patients with IVIG sensitivity and 20 healthy controls validated serum methionine as a biomarker for KD patients with AUROC of 0.86. Elevation of serum DNMT1 activities, but no differences of DNMT3a and DNMT3b, were observed in KD patients when comparing with those in the HCs.

CONCLUSIONS

Our study validated that serum methionine was a potential biomarker for KD, the alteration of which is associated with the activation of DNMT1 in KD patients.

Flaxseed oil fraction reverses cardiac remodeling at a molecular level: improves cardiac function, decreases apoptosis, and suppresses miRNA-29b and miRNA 1 gene expression

Flaxseed is an ancient commercial oil that historically has been used as a functional food to lower cholesterol levels. However, despite its longstanding treatment, there is currently a lack of scientific evidence to support its role in the management of cardiac remodeling. This study aimed to address this gap in knowledge by examining the molecular mechanism of standardized flaxseed oil in restoring cardiac remodeling in the heart toxicity vivo model. The oil fraction was purified, and the major components were standardized by qualitative and quantitative analysis. In vivo experimental design was conducted using isoproterenol ISO (85 mg/kg) twice subcutaneously within 24 h between each dose. The rats were treated with flaxseed oil fraction (100 mg/kg orally) and the same dose was used for omega 3 supplement as a positive control group. The GC-MS analysis revealed that α-linolenic acid (24.6%), oleic acid (10.5%), glycerol oleate (9.0%) and 2,3-dihydroxypropyl elaidate (7%) are the major components of oil fraction. Physicochemical analysis indicated that the acidity percentage, saponification, peroxide, and iodine values were 0.43, 188.57, 1.22, and 122.34 respectively. As compared with healthy control, ISO group-induced changes in functional cardiac parameters. After 28-day pretreatment with flaxseed oil, the results indicated an improvement in cardiac function, a decrease in apoptosis, and simultaneous prevention of myocardial fibrosis. The plasma levels of BNP, NT-pro-BNP, endothelin-1, Lp-PLA2, and MMP2, and cTnI and cTn were significantly diminished, while a higher plasma level of Topo 2B was observed. Additionally, miRNA - 1 and 29b were significantly downregulated. These findings provide novel insight into the mechanism of flaxseed oil in restoring cardiac remodeling and support its future application as a cardioprotective against heart diseases.

Biosensors for natriuretic peptides in cardiovascular diseases. A review

Heart failure (HF) is a complex clinical syndrome associated with high rates of morbidity and mortality. Over the years, it has been crucial to find accurate biomarkers capable of doing a precise monitor of HF and provide an early diagnosis. Of these, it has been established an important role of natriuretic peptides in HF assessment. Moreover, the development of biosensors has been garnering interest as new diagnostic medical tools. In this review we first provide a general overview of HF, its pathogenesis, and diagnostic features. We then discuss the role of natriuretic peptides in heart failure by characterizing them and point out their potential as biomarkers. Finally, we adress the evolution of biosensors development and the available natriuretic peptides biosensors for disease monitoring.

Associations between diet quality and NT-proBNP in U.S. adults, NHANES 1999-2004

Objective

N-terminal pro-brain-type natriuretic peptide (NT-proBNP) is a marker of cardiac wall stress and is a predictor of cardiovascular disease. Higher diet quality is associated with lower risk of cardiovascular disease. The association between diet quality and subclinical cardiovascular disease assessed by NT-proBNP is uncharacterized. We investigated the associations between diet quality, using Healthy Eating Index-2015 (HEI-2015), and NT-proBNP from the National Health and Nutrition Examination Survey (NHANES) 1999-2004.

Methods

We included 9,782 adults from NHANES 1999-2004 without self-reported cardiovascular disease. The HEI-2015 ranges from 0 to 100, with higher scores indicating better diet quality. The HEI-2015 was categorized into sex-specific quintiles. Regression models were used to quantify associations between the overall HEI-2015 score and its 13 components with log-transformed NT-proBNP. The beta coefficients were converted to percent differences.

Results

Among 9,782 participants, mean age was 45 years, 48% were men, and 72% were non-Hispanic White adults. After adjusting for sociodemographic characteristics, lifestyle factors, and medical history, those in the highest vs. lowest HEI-2015 quintile had an 8.5% (95% CI: -14.6% to -2.0%) lower NT-proBNP level. There was a dose-response association between HEI-2015 and NT-proBNP (P value for trend = 0.01). Each 1-unit higher in sodium and added sugars score indicating lower intake was associated with lower NT-proBNP by 7.7% (95% CI: -12.8% to -2.2%) and 6.5% (95% CI: -12.0% to -0.7%), respectively.

Conclusion

Higher diet quality, especially lower intakes of sodium and added sugars, was associated with lower serum levels of NT-proBNP.

Potential roles of 4HNE-adducted protein in serum extracellular vesicles as an early indicator of oxidative response against doxorubicin-induced cardiomyopathy in rats

Late-onset cardiomyopathy is becoming more common among cancer survivors, particularly those who received doxorubicin (DOXO) treatment. However, few clinically available cardiac biomarkers can predict an unfavorable cardiac outcome before cell death. Extracellular vesicles (EVs) are emerging as biomarkers for cardiovascular diseases and others. This study aimed to measure dynamic 4-hydroxynonenal (4HNE)-adducted protein levels in rats treated chronically with DOXO and examine their link with oxidative stress, antioxidant gene expression in cardiac tissues, and cardiac function. Twenty-two male Wistar rats were randomly assigned to receive intraperitoneal injection of normal saline (n = 8) or DOXO (3 mg/kg, 6 doses, n = 14). Before and after therapy, serum EVs and N-terminal pro-B-type natriuretic peptide (NT-proBNP) levels were determined. Tunable resistive pulse sensing was used to measure EV size and concentration. ELISA was used to assess 4HNE-adducted protein in EVs and cardiac tissues. Differential-display reverse transcription-PCR was used to quantitate cardiac Cat and Gpx1 gene expression. Potential correlations between 4HNE-adducted protein levels in EVs, cardiac oxidative stress, antioxidant gene expression, and cardiac function were determined. DOXO-treated rats showed more serum EV 4HNE-adducted protein than NSS-treated rats at day 9 and later endpoints, whereas NT-proBNP levels were not different between groups. Moreover, on day 9, surviving rats' EVs had higher levels of 4HNE-adducted protein, and these correlated positively with concentrations of heart tissue 4HNE adduction and copy numbers of Cat and Gpx1, while at endpoint correlated negatively with cardiac functions. Therefore, 4HNE-adducted protein in serum EVs could be an early, minimally invasive biomarker of the oxidative response and cardiac function in DOXO-induced cardiomyopathy.

Bronchial epithelial and airway smooth muscle cell interactions in health and disease

Chronic pulmonary diseases such as asthma, COPD, and Idiopathic pulmonary fibrosis are significant causes of mortality and morbidity worldwide. Currently, there is no radical treatment for many chronic pulmonary diseases, and the treatment options focus on relieving the symptoms and improving lung function. Therefore, efficient therapeutic agents are highly needed. Bronchial epithelial cells and airway smooth muscle cells and their crosstalk play a significant role in the pathogenesis of these diseases. Thus, targeting the interactions of these two cell types could open the door to a new generation of effective therapeutic options. However, the studies on how these two cell types interact and how their crosstalk adds up to respiratory diseases are not well established. With the rise of modern research tools and technology, such as lab-on-a-chip, organoids, co-culture techniques, and advanced immunofluorescence imaging, a substantial degree of evidence about these cell interactions emerged. Hence, this contribution aims to summarize the growing evidence of bronchial epithelial cells and airway smooth muscle cells crosstalk under normal and pathophysiological conditions. The review first discusses the impact of airway smooth muscle cells on the epithelium in inflammatory settings. Later, it examines the role of airway smooth muscle cells in the early development of bronchial epithelial cells and their recovery after injury. Then, it deliberates the effects of both healthy and stressed epithelial cells on airway smooth muscle cells, taking into account three themes; contraction, migration, and proliferation.

Enhancement of Bottle Gourd Oil Activity via Optimized Self-Dispersing Lipid Formulations (SDLFs) to Mitigate Isoproterenol-Evoked Cardiac Toxicity in Rats via Modulating BMP, MMP2, and miRNA-21 and miRNA-23a Genes' Expression

Bottle gourd (BG) oil (family Cucurbitaceae) has several pharmacological activities including a reduction of the hazard of cardiovascular and atherosclerosis conditions. This work aimed to develop and optimize self-dispersing lipid formulations (SDLFs) of BG oil by applying a full 32 factorial design. The formulation variables (oil concentration and surfactant mixture ratio) showed an obvious impact on the characters of the prepared BG-SDLFs including droplet size (DS), polydispersity index (PDI), emulsification time (ET), and transmission percentage (Tr%). The optimum BG-SDLF composed of 30% oil and Tween 80/Cremophor® RH40 (1:1) showed good emulsification characteristics and a better drug release profile compared with BG oil. In vivo study in isoproterenol-injected rats showed that BG oil and the optimized BG-SDLF improved cardiac function, by elevating the miRNA-23a gene expression level and decreasing miRNA-21 gene expression. They also caused the inhibition of the plasma B-type natriuretic peptide (BNP), N-terminal proatrial natriuretic peptide (NT-pro-BNP), cystatin c, galectin-3, lipoprotein-associated phospholipase A2 (Lp-PLA2), matrix metallopeptidase 2 (MMP2), cardiac troponin I (cTnI), and cardiac troponin T (cTnT). Our study demonstrated that BG oil and the optimized BG-SDLF provided a cardioprotection against isoproterenol-induced cardiac toxicity with better results in groups treated with the optimized BG-SDLF.

An impedimetric immunosensor based on chitosan-Au nanoparticles-reduced graphene oxide nanosheet composite modified PG electrode for detection of brain natriuretic peptide

An ultrasensitive impedimetric immunosensor was developed to detect brain natriuretic peptide (BNP) for early diagnosis of heart failure. To construct this immunosensor, anti-BNP antibodies were immobilized covalently onto nanocomposite of chitosan-Au nanoparticles and reduced graphene oxide nanosheets (CHIT-Au@rGONs) electrodeposited onto pencil graphite electrode. This approach impedes charge transfer resistance (Rct) value proportionally to the BNP captured by antigen-antibody interactions. The observed Rct values by this immunosensor, were correlated with linear concentrations of BNP in the range, 1 × 10-2 to 1 × 103 pg/mL, with a limit of detection of 12 pg/mL and limit of quantification of 36.3 pg/mL. The immunosensor detected BNP in spiked human sera. The analytic recovery of added BNP in human sera was 97.04%. The present method was fairly consistent with commercial approach. The working electrode was stored for 2 months in cold. BSA-IgG had no interference in the electrode activity showing its high specificity for BNP. This novel approach provided a new POC-diagnostics, as direct sample measurements are easier and more efficient by this immunosensor compared to existing immunosensors.

Supplementary Information

The online version contains supplementary material available at 10.1007/s13205-023-03704-x.

Myocardial capacity of mitochondrial oxidative phosphorylation in response to prolonged electromagnetic stress

Introduction

Mitochondria are central energy generators for the heart, producing adenosine triphosphate (ATP) through the oxidative phosphorylation (OXPHOS) system. However, mitochondria also guide critical cell decisions and responses to the environmental stressors.

Methods

This study evaluated whether prolonged electromagnetic stress affects the mitochondrial OXPHOS system and structural modifications of the myocardium. To induce prolonged electromagnetic stress, mice were exposed to 915 MHz electromagnetic fields (EMFs) for 28 days.

Results

Analysis of mitochondrial OXPHOS capacity in EMF-exposed mice pointed to a significant increase in cardiac protein expression of the Complex I, II, III and IV subunits, while expression level of α-subunit of ATP synthase (Complex V) was stable among groups. Furthermore, measurement of respiratory function in isolated cardiac mitochondria using the Seahorse XF24 analyzer demonstrated that prolonged electromagnetic stress modifies the mitochondrial respiratory capacity. However, the plasma level of malondialdehyde, an indicator of oxidative stress, and myocardial expression of mitochondria-resident antioxidant enzyme superoxide dismutase 2 remained unchanged in EMF-exposed mice as compared to controls. At the structural and functional state of left ventricles, no abnormalities were identified in the heart of mice subjected to electromagnetic stress.

Discussion

Taken together, these data suggest that prolonged exposure to EMFs could affect mitochondrial oxidative metabolism through modulating cardiac OXPHOS system.

Approaches and Challenges for Biosensors for Acute and Chronic Heart Failure

Heart failure (HF) is a cardiovascular disease defined by several symptoms that occur when the heart cannot supply the blood needed by the tissues. HF, which affects approximately 64 million people worldwide and whose incidence and prevalence are increasing, has an important place in terms of public health and healthcare costs. Therefore, developing and enhancing diagnostic and prognostic sensors is an urgent need. Using various biomarkers for this purpose is a significant breakthrough. It is possible to classify the biomarkers used in HF: associated with myocardial and vascular stretch (B-type natriuretic peptide (BNP), N-terminal proBNP and troponin), related to neurohormonal pathways (aldosterone and plasma renin activity), and associated with myocardial fibrosis and hypertrophy (soluble suppression of tumorigenicity 2 and galactin 3). There is an increasing demand for the design of fast, portable, and low-cost biosensing devices for the biomarkers related to HF. Biosensors play a significant role in early diagnosis as an alternative to time-consuming and expensive laboratory analysis. In this review, the most influential and novel biosensor applications for acute and chronic HF will be discussed in detail. These studies will be evaluated in terms of advantages, disadvantages, sensitivity, applicability, user-friendliness, etc.

Ultrafast Early Warning of Heart Attacks through Plasmon-Enhanced Raman Spectroscopy using Collapsible Nanofingers and Machine Learning

As the leading cause of death, heart attacks result in millions of deaths annually, with no end in sight. Early intervention is the only strategy for rescuing lives threatened by heart disease. However, the detection time of the fastest heart-attack detection system is >15 min, which is too long considering the rapid passage of life. In this study, a machine learning (ML)-driven system with a simple process, low-cost, short detection time (only 10 s), and high precision is developed. By utilizing a functionalized nanofinger structure, even a trace amount of biomarker leaked before a heart attack can be captured. Additionally, enhanced Raman profiles are constructed for predictive analytics. Five ML models are developed to harness the useful characteristics of each Raman spectrum and provide early warnings of heart attacks with >98% accuracy. Through the strategic combination of nanofingers and ML algorithms, the proposed warning system accurately provides alerts on silent heart-attack attempts seconds ahead of actual attacks.

Levels of TNF-α and Soluble TNF Receptors in Normal-Weight, Overweight and Obese Patients with Dilated Non-Ischemic Cardiomyopathy: Does Anti-TNF Therapy Still Have Potential to Be Used in Heart Failure Depending on BMI?

Background. We sought to measure the levels of adipokines, TNF-α and soluble receptors (sTNFr1, sTNFr2) in heart failure patients with reduced ejection fraction (HFrEF) due to non-ischemic cardiomyopathy (nDCM). Methods. A total of 123 patients with HFrEF due to nDCM were divided into three groups according to BMI: 34 (27.6%) normal weight, 56 (45.5%) overweight and 33 (26.8%) obese. A six-minute walk test, echocardiography and right heart catheterization were performed. Serum concentrations of adiponectin, leptin, NT-proBNP, blood hemoglobin, sodium, creatinine, ALAT, AspAT, bilirubin, CRP, lipids, TNF-α, sTNFr1 and sTNFr2 receptors were measured. Results. Obese patients had the lowest NT-proBNP concentrations, significantly higher leptin levels and higher leptin/adiponectin ratios. The concentration of sTNFr1 was higher in normal-weight patients. In all groups, TNF-α concentrations correlated positively with sTNFr1 (p < 0.001). Higher levels of sTNFr1 were associated with higher sTNFr2 (p < 0.001) and CRP (p < 0.001). Moreover, the concentration of sTNFr2 positively correlated with CRP (p < 0.05) and adiponectin (p < 0.001). Levels of TNF-α were not associated with elevated CRP. Conclusion: This study demonstrated that changes in the concentrations of TNF and its receptors differ between groups of patients with different BMI. These findings suggest that the effective use of anti-TNF therapy is dependent not only on BMI, but also on concentrations of TNF-α receptors and other laboratory parameters.

Maternal Serum and Umbilical Cord Brain Natriuretic Peptide Levels in Fetuses with Intrauterine Growth Restriction

Aim: We compared maternal serum and fetal cord blood proBNP levels in healthy pregnancies to those with intrauterine growth restriction (IUGR). Methods: Prospectively, maternal and cord blood samples at childbirth of 40 pregnant women with isolated IUGR and 40 healthy pregnant women were evaluated for ProBNP levels. Results: The mean serum ProBNP level was significantly higher in newborn cord blood with IUGR than in the control group (181.28 ± 145.37 vs. 91.41 ± 49.77 pg/mL, p = <0.01). Mean serum ProBNP level trended higher in women with IUGR compared to the controls, but was not statistically significant (124.21 ± 113.32 vs. 88.73 ± 85.18 pg/mL, p= >0.05). Conclusion: Third trimester mean proBNP in fetal cord blood are increased in IUGR fetuses at term birth compared to pregnancies with normal fetal growth.

A Pathophysiological Approach To Current Biomarkers

Biomarkers are necessary for screening and diagnosing numerous diseases, predicting the prognosis of patients, and following-up treatment and the course of the patient. Everyday new biomarkers are being used in clinics for these purposes. This section will discuss the physiological roles of the various current biomarkers in a healthy person and the pathophysiological mechanisms underlying the release of these biomarkers. This chapter aims to gain a new perspective for evaluating and interpreting the most current biomarkers.

Modulation of blood pressure regulatory genes in the Agtrap-Plod1 locus associated with a deletion in Clcn6

The AGTRAP-PLOD1 locus is a conserved gene cluster containing several blood pressure regulatory genes, including CLCN6, MTHFR, NPPA, and NPPB. Previous work revealed that knockout of Clcn6 on the Dahl Salt-Sensitive (SS) rat background (SS-Clcn6) resulted in lower diastolic blood pressure compared to SS-WT rats. Additionally, a recent study found sickle cell anemia patients with mutations in CLCN6 had improved survival and reduced stroke risk. We investigated whether loss of Clcn6 would delay the mortality of Dahl SS rats on an 8% NaCl (HS) diet. No significant difference in survival was found. The ability of Clcn6 to affect mRNA expression of nearby Mthfr, Nppa, and Nppb genes was also tested. On normal salt (0.4% NaCl, NS) diets, renal Mthfr mRNA and protein expression were significantly increased in the SS-Clcn6 rats. MTHFR reduces homocysteine to methionine, but no differences in circulating homocysteine levels were detected. Nppa mRNA levels in cardiac tissue from SS-Clcn6 rat in both normotensive and hypertensive conditions were significantly reduced compared to SS-WT. Nppb mRNA expression in SS-Clcn6 rats on a NS diet was also substantially decreased. Heightened Mthfr expression would be predicted to be protective; however, diminished Nppa and Nppb expression could be deleterious and by preventing or blunting vasodilation, natriuresis, and diuresis that ought to normally occur to offset blood pressure increases. The conserved nature of this genetic locus in humans and rats suggests more studies are warranted to understand how mutations in and around these genes may be influencing the expression of their neighbors.

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.

NT Pro-BNP can be used as a risk predictor of clinical atrial fibrillation with or without left atrial enlargement

Background

NT Pro‐BNP is a blood marker secreted by cardiomyocytes. Myocardial stretch is the main factor to stimulate NT Pro‐BNP secretion in cardiomyocytes. NT Pro‐BNP is an important risk factor for cardiac dysfunction, stroke, and pulmonary embolism. So does atrial myocyte stretching occur when patients have atrial fibrillation (AF)? Whether atrial muscle stretch induced by AF leads to increased NT Pro‐BNP remains unclear. The purpose of this study is to investigate the relationship between NT Pro‐BNP and AF.

Hypothesis

AF can cause changes in myocardial tension. Changes in myocardial tension may lead to increased secretion of NT Pro‐BNP. We hypothesize that NT Pro‐BNP may increase in AF with or without LAD enlargement.

Methods

This clinical study is an observational study and has been approved by the Ethics Committee of the First Affiliated Hospital of Xi'an Jiaotong University. Ethical approval documents is attached. The study retrospectively reviewed 1345 patients with and without AF. After excluding 102 patients who were not eligible, the final total sample size was 1243 cases: AF group 679 patients (378, 55.7% males) and non‐AF group 564 patients (287, 50.8% males). NT Pro‐BNP was observed in AF group and non‐AF group with or without LAD. After adjusting for age, gender, BMI, left atrial diameter, hypertension, diabetes, coronary heart disease, and cerebral infarction, NT Pro‐BNP remains statistically significant with AF.

Conclusion

NT Pro‐BNP can be used as a risk predictor of AF with or without left atrial enlargement.

Brain Natriuretic Peptide as a Marker of Adverse Neurological Outcomes Among Survivors of Cardiac Arrest

BACKGROUND

Neurological prognosis after cardiac arrest remains ill-defined. Plasma brain natriuretic peptide (BNP) may relate to poor neurological prognosis in brain-injury patients, though it has not been well studied in survivors of cardiac arrest.

METHODS

We performed a retrospective review and examined the association of BNP with mortality and neurological outcomes at discharge in a cohort of cardiac arrest survivors enrolled from January 2012 to December 2016 at the Wake Forest Baptist Hospital, in North Carolina. Cerebral performance category (CPC) and modified Rankin scales were calculated from the chart based on neurological evaluation performed at the time of discharge. The cohort was subdivided into quartiles based on their BNP levels after which multivariable adjusted logistic regression models were applied to assess for an association between BNP and poor neurological outcomes as defined by a CPC of 3 to 4 and a modified Rankin scale of 4 to 5.

RESULTS

Of the 657 patients included in the study, 254 patients survived until discharge. Among these, poor neurological status was observed in 101 (39.8%) patients that had a CPC score of 3 to 4 and 97 patients (38.2%) that had a modified Rankin scale of 4 to 5. Mean BNP levels were higher in patients with poor neurological status compared to those with good neurological status at discharge (P = .03 for CPC 3-4 and P = .02 for modified Rankin score 4-5). BNP levels however, did not vary significantly between patients that survived and those that expired (P = .22). BNP did emerge as a significant discriminator between patients with severe neurological disability at discharge when compared to those without. The area under the curve for BNP predicting a modified Rankin score of 4 to 5 was 0.800 (95% confidence interval [CI] 0.756-0.844, P < .001) and for predicting CPC 3 to 4 was 0.797 (95% CI 0.756-0.838, P < .001). BNP was able to significantly improve the net reclassification index and integrated discriminatory increment (P < .05). BNP was not associated with long-term all-cause mortality (P > .05).

CONCLUSIONS

In survivors of either inpatient or out-of-hospital cardiac arrest, increased BNP levels measured at the time of arrest predicted severe neurological disability at discharge. We did not observe an independent association between BNP levels and long-term all-cause mortality. BNP may be a useful biomarker for predicting adverse neurological outcomes in survivors of cardiac arrest.

Predictive value of cardiac markers in the prognosis of COVID-19 in children

Background and aim

Occasionally, children with COVID-19 may develop arrhythmia, myocarditis, and cardiogenic shock involving multisystemic inflammatory syndrome in children (MIS-C). This study aimed to identify the laboratory parameters that may predict early cardiovascular involvement in these patients.

Materials and methods

Data of 320 pediatric patients, aged 0–18 years (average age, 10.46 ± 5.77 years; 156 female), with positive COVID-19 reverse transcription–polymerase chain reaction test and with cardiac biomarkers at the time of admission to the pediatric emergency department were retrospectively scanned. The age, sex, COVID-19-associated symptoms, pro-brain natriuretic peptide (proBNP), CK-MB, and troponin I levels of the patients were recorded.

Results

Fever was noted in 58.1% of the patients, cough in 29.7%, diarrhea in 7.8%, headache in 14.7%, sore throat in 17.8%, weakness in 17.8%, abdominal pain in 5%, loss of taste in 4.1%, loss of smell in 5.3%, nausea in 3.4%, vomiting in 3.8%, nasal discharge in 4.4%, muscle pain in 5%, and loss of appetite in 3.1%. The proBNP value ≥282 ng/L predicted the development of MIS-C with 100% sensitivity and 93% specificity [AUC: 0.985 (0.959–1), P < 0.001]; CK-MB value ≥2.95 with 80% sensitivity and 77.6% specificity [AUC: 0.792 (0.581–1), P = 0.026]; and troponin I value ≥0.03 with 60% sensitivity and 99.2% specificity [AUC: 0.794 (0.524–1)].

Conclusions

Cardiac markers (proBNP and troponin I), especially proBNP, could be used to detect early diagnosis of cardiac involvement and/or MIS-C in pediatric patients with COVID-19 and to predict related morbidity and mortality.

The Role of ProBNP on Prognosis in Scorpion Stings

INTRODUCTION

Scorpion stings are a major health problem with potentially fatal consequences. Children under the age of 10 y especially face a great risk. Predicting the prognosis is important in reducing mortality and morbidity because it enables the use of early treatment options. In this study, we examine the relationship between proBNP and prognosis in scorpion stings.

METHODS

This is a retrospective analysis of patients aged ≤18 y who were admitted to the child emergency service with a scorpion sting. We examined the demographical data, clinical findings, laboratory records, treatments, and results of the patients. We classified stage 1 and stage 2 scorpion envenomation as group 1 (mild-moderate) and stage 3 and 4 as group 2 (severe). A t test was used for normally distributed data, and the Mann-Whitney U test was used for nonnormally distributed data. The correlation analysis was done using the Spearman test.

RESULTS

There were 32 (74%) patients in the mild-moderate group and 11 (26%) in the severe group. ProBNP 1 was significantly higher in the severe group at admission (P=0.016). There was no difference between the troponin I values (P=0.051). ProBNP 2 (12th hour) and proBNP 3 (24th hour) were higher in the severe group (P=0.001 and P=0.032, respectively). There was a negative correlation between proBNP and echocardiographic findings involving ejection fraction and shortening fraction (r=-0.703, P=0.002).

CONCLUSIONS

In our study, the first proBNP values were significantly higher in the severe group. This suggests that proBNP may be beneficial in predicting prognosis.

Use of B-Type Natriuretic Peptide (BNP) and N-Terminal proBNP (NT-proBNP) as Diagnostic Tests in Adults With Suspected Heart Failure: A Health Technology Assessment

BACKGROUND

Heart failure is a complex clinical syndrome that usually presents with breathlessness, leg edema, and fatigue. Clinically measurable natriuretic neurohormones such as B-type natriuretic peptide (BNP) and N-terminal proBNP (NT-proBNP) are elevated in people with heart failure. We conducted a health technology assessment of BNP and NT-proBNP tests for people with suspected heart failure, which included an evaluation of diagnostic accuracy, clinical impact, cost-effectiveness, the budget impact of publicly funding BNP and NT-proBNP tests, and patient preferences and values.

METHODS

We performed a literature search of previously published systematic reviews of the clinical evidence. We conducted an overview of reviews and included only reviews with a low risk of bias as assessed using the Risk of Bias in Systematic Reviews tool (ROBIS). We excluded any reviews where we found 100% overlap of included primary studies and selected systematic reviews or health technology assessments published after 2006 for inclusion.We performed an economic literature review of BNP and NT-proBNP testing in people with suspected heart failure. Medical and health economic databases were searched from database inception until July 25, 2019. Next, we assessed the cost-effectiveness of BNP and NT-proBNP based on the published economic literature. We transferred the cost-effectiveness results of two applicable, recent economic evaluations from the National Institute for Health and Care Excellence (NICE) to the Ontario setting in lieu of conducting de novo primary economic evaluations. We also estimated the budget impact of publicly funding BNP and NT-proBNP tests in people with suspected heart failure in Ontario over the next 5 years.To contextualize the potential value of BNP and NT-proBNP testing, we spoke with people with suspected heart failure.

RESULTS

We included eight systematic reviews in the clinical evidence review. B-type natriuretic peptides and NT-proBNP had a high pooled sensitivity (80% to 94% and 86% to 96%, respectively; strength of evidence: high) and a low pooled negative likelihood ratio (0.08-0.30 and 0.09-0.23, respectively; strength of evidence: not reported) within varying thresholds or cut points and settings, as reported in seven systematic reviews. In one systematic review, when BNP or NT-proBNP was used in the diagnosis of heart failure in the emergency department (ED), there was a decrease in the mean length of hospital stay (-1.22 days; confidence interval [CI] -2.31 to -0.14; Grading of Recommendations Assessment, Development, and Evaluation [GRADE] Working Group criteria: Moderate). B-type natriuretic peptide testing did not reduce hospital admission rates (odds ratio [OR]: 0.82; CI: 0.67-1.01; GRADE: Moderate), 30-day hospital readmission rates (OR: 0.88; CI: 0.64-1,20; GRADE: Moderate), or hospital mortality rates (OR: 0.96; CI: 0.65-1.41; GRADE: Moderate). No systematic review was identified that addressed the impact on clinical outcomes of BNP use in the community setting.Our economic literature review found a total of 12 studies evaluating the cost-effectiveness of BNP or NT-proBNP testing in patients with suspected heart failure. The studies suggested that BNP or NT-proBNP tests, when used in addition to standard clinical investigations, were either dominant (less costly and more effective) or cost-effective across different countries (including Canada) and settings.Two economic evaluations conducted by NICE were considered applicable to our research question and of high methodological quality. Based on the transferred results from the two NICE economic evaluations, we concluded that BNP and NT-proBNP were highly likely to be cost-effective in Ontario in the ED setting, and NT-proBNP was highly likely to be cost-effective in the community care setting.Our budget impact analysis estimated that over the next 5 years, publicly funding BNP and NT-proBNP tests would result in an additional cost of $38 million in the ED (at a cost of $75 per test) and a cost savings of $20 million in community care (at a cost of $28 per test).We received strong support from interview participants about BNP or NT-proBNP diagnostic testing. The main reason was the perceived potential benefit of receiving a speedier diagnosis. The overall process, from diagnosis to treatment, is a substantial emotional burden for patients and caregivers, and for those living further away from secondary or tertiary care settings. An earlier diagnosis could allow patients to receive treatment at a hospital better equipped to manage their potentially fatal symptoms and conditions.

CONCLUSIONS

B-type natriuretic peptide and NT-proBNP tests have high sensitivity and low negative likelihood ratio, suggesting that concentrations of either natriuretic peptides within the appropriate cut points can rule out the presence of heart failure with a high degree of confidence. Additionally, BNP or NT-proBNP testing along with usual care in an ED setting likely can reduce the length of hospital stay by at least 1 day but likely results in little to no difference in hospital mortality, 30-day readmission, or admission rates to hospital.Based on the published economic literature, we expected BNP or NT-proBNP tests used in addition to standard clinical investigations to be cost-effective as a rule-out test in patients with suspected heart failure in Ontario. If BNP and NT-proBNP tests are publicly funded in Ontario, we estimated that there would be additional costs in the ED setting (due to increased detection of heart failure) and savings in community care (due to reduced referrals to echocardiography and cardiologists).People we interviewed gave BNP and NT-proBNP testing strong support, citing the perceived benefits of quicker, more accurate diagnoses that could reduce misdiagnoses, stress, and the burden on patients and caregivers.

Is ProBNP a New Marker for Predicting Intrauterine Growth Restriction?

PURPOSE

To evaluate the usability of first-trimester maternal serum ProBNP levels in the prediction of intrauterine growth restriction (IUGR). Methods In this prospective study, blood samples taken from 500 women who applied to our polyclinic for routine serum aneuploidy screening between the 11-14th gestational weeks were centrifuged. The obtained plasma samples were placed in Eppendorf tubes and stored at -80+°C. For the final analysis, first-trimester maternal serum ProBNP levels of 32 women diagnosed with postpartum IUGR and 32 healthy women randomly selected as the control group were compared. FGR was defined as estimated fetal weight below the 10th percentile for the gestational age.

RESULTS

The mean ProBNP levels were statistically and significantly higher in the women with intrauterine growth restriction (113.73±94.69 vs. 58.33±47.70 pg/mL, p<0.01). At a cut-off level of 50.93, ProBNP accurately predicted occurrence of IUGR (AUC+= 0.794 (95% confidence interval 0.679-0.910), p+= 0.001) with sensitivity and specificity rates of 78.1 and 69.0%, respectively. Conclusion First-trimester serum ProBNP level was significantly higher in women who developed IUGR compared to healthy controls. First-trimester ProBNP level can be used as a potential marker to predict the development of IUGR in pregnant women.

B-type natriuretic peptide (BNP) predicts 90-day mortality and need for paracentesis in cirrhotic patients without systolic heart failure

Fluid overload is a common complication in patients with cirrhosis. B-type natriuretic peptide (BNP) is a marker of increased blood volume, commonly used in heart failure, that has been shown to be elevated in patients with liver disease. This study examined if BNP levels can be used to determine prognosis and predict worsening of ascites in patients with cirrhosis without concomitant heart disease. A retrospective study was performed at a large urban hospital in Chicago, Illinois and included 430 patients with cirrhosis who had BNP levels ordered during their hospital stay. Patients with clinical heart failure, arrhythmias or pulmonary hypertension were excluded. The primary outcome was 90-day mortality and the secondary outcome was a requirement for therapeutic paracentesis in the 90 days following BNP results. 53 patients (12%) had BNP levels ≥ 300 pg/mL. They had significantly increased serum levels of creatinine, bilirubin, and International Normalized Ratio (INR) when compared to those with BNP < 300 pg/mL. Patients with higher BNP had significantly higher mortality rates (HR 3.49; p = 0.037) and were more likely to require therapeutic paracentesis (HR 2.26; p = 0.02) in the next 90 days. A BNP ≥ 300 pg/mL had specificity of 88.2% in predicting 90-day mortality. BNP may serve as a practical and reliable marker of underlying disease severity in patients with cirrhosis, with potential to be included in prognostication tools for assessment of end-stage liver disease.

Differential Role of Circulating microRNAs to Track Progression and Pre-Symptomatic Stage of Chronic Heart Failure: A Pilot Study

(1)Background: Chronic heart failure (CHF) contributes to the overall burden of cardiovascular disease. Early identification of at-risk individuals may facilitate the targeting of precision therapies. Plasma microRNAs are promising circulating biomarkers for their implications with cardiac pathologies. In this pilot study, we investigate the possible exploitability of circulating micro-RNAs (miRNAs) to track chronic heart failure (CHF) occurrence, and progression from NYHA class I to IV. (2)Methods: We screened 367 microRNAs using TaqMan microRNA Arrays in plasma samples from healthy controls (HC) and CHF NYHA-class I-to-IV patients (5/group). Validation was performed by singleplex assays on 10 HC and 61 CHF subjects. Differences in the expression of validated microRNAs were evaluated through analysis of covariance (ANCOVA). Associations between N-terminal pro-BNP (NT-proBNP), left ventricular end-diastolic volume (LVEDV) or peak oxygen uptake (VO2 peak) and plasma microRNA were assessed by multivariable linear regression analysis. (3)Results: Twelve microRNAs showed higher expression in CHF patients vs. HC. Seven microRNAs were associated with NT-proBNP concentration; of these, miR-423-5p was also an independent predictor of LVEDV. Moreover, miR-499-5p was a predictor of the VO2 peak. Finally, a cluster of 5 miRNAs discriminated New York Heart Association (NYHA) class-I from HC subjects. (4)Conclusions: Our data suggest that circulating miRNAs have the potential to serve as pathophysiology-based markers of HF status and progression, and as indicators of pre-symptomatic individuals.

Disproportionately low BNP levels in patients of acute heart failure with preserved vs. reduced ejection fraction

BACKGROUND

B-type natriuretic peptide (BNP) has been widely used for the diagnosis of heart failure, its severity, and prognosis. However, little is known about factors related to disproportionately low BNP levels even during acute heart failure conditions.

METHODS AND RESULTS

Among 424 patients hospitalized for acute heart failure, we categorized the patients into the HFpEF (LVEF > 50%) or HFrEF (LVEF ≤ 50%) group and subdivided them into disproportionately low BNP (LB) group and high BNP (HB) group using a cut-off BNP level of 200 pg/mL at admission. The proportion of patients with LB was higher in the HFpEF group (22.2%) than in the HFrEF group (10.9%, p = 0.002). Patients with LB had a high BMI, lower blood pressure, and history of previous cardiovascular surgery in the HFpEF group, while patients in the HFrEF group had a high BMI and smaller left ventricular end-diastolic volume index. Furthermore, presence of LB in the HFrEF group was related to good prognosis, but LB in the HFpEF group was an indicator of poor prognosis as HB group.

CONCLUSIONS

The factors associated with LB were different between the HFpEF and HFrEF groups. LB was related to good prognosis in HFrEF, but not in HFpEF.

B-Type Natriuretic Peptide as a Significant Brain Biomarker for Stroke Triaging Using a Bedside Point-of-Care Monitoring Biosensor

Stroke is a widespread condition that causes 7 million deaths globally. Survivors suffer from a range of disabilities that affect their everyday life. It is a complex condition and there is a need to monitor the different signals that are associated with it. Stroke patients need to be rapidly diagnosed in the emergency department in order to allow the admission of the time-limited treatment of tissue plasminogen activator (tPA). Stroke diagnostics show the use of sophisticated technologies; however, they still contain limitations. The hidden information and technological advancements behind the utilization of biomarkers for stroke triaging are significant. Stroke biomarkers can revolutionize the way stroke patients are diagnosed, monitored, and how they recover. Different biomarkers indicate different cascades and exhibit unique expression patterns which are connected to certain pathologies in the human body. Over the past decades, B-type natriuretic peptide (BNP) and its derivative N-terminal fragment (NT-proBNP) have been increasingly investigated and highlighted as significant cardiovascular biomarkers. This work reviews the recent studies that have reported on the usefulness of BNP and NT-proBNP for stroke triaging. Their classification association is also presented, with increased mortality in stroke, correlation with cardioembolic stroke, and an indication of a second stroke recurrence. Moreover, recent scientific efforts conducted for the technological advancement of a bedside point-of-care (POC) device for BNP and NT-proBNP measurements are discussed. The conclusions presented in this review may hopefully assist in the major efforts that are currently being conducted in order to improve the care of stroke patients.

Analysis of B-type natriuretic peptide impurities using label-free data-independent acquisition mass spectrometry technology

Objectives

Synthetic B-type natriuretic peptide (BNP) is employed in most clinical testing platforms as a raw material of calibrator. Characterization of impurities with structures similar (BNPstrimp compounds) to that of BNP is a reasonable way to decrease clinical measurement errors and improve drug safety.

Methods

A novel quantitative method targeted towards BNPstrimp compounds was developed. First, the peptide samples were separated and identified using ultra-performance liquid chromatography, coupled with high-resolution mass spectrometry (MS). To evaluate biological activity further, BNPstrimp immunoaffinity was investigated using western blot (WB) assays. Second, a quantitative label-free data-independent acquisition (DIA) MS approach was developed, and the internal standard peptide (ISP) was hydrolyzed. Absolute quantification was performed using an isotope dilution MS (ID-MS) approach. Third, method precision was investigated using the C-peptide reference material.

Results

Seventeen BNPstrimp compounds were identified in synthetic BNP, and 10 of them were successfully sequenced. The immunoassay results indicated that deaminated, oxidized, and isomerized BNPstrimp compounds exhibited weaker immunoaffinity than intact BNP1-32. The mass fraction of the synthetic solid ISP1-16, quantified by ID-MS, was 853.5 (±17.8) mg/g. Validation results indicated that the developed method was effective and accurate for the quantitation of the well-separated BNP impurities.

Conclusions

The developed approach was easy to perform, and it was suitable for the parallel quantification of low-abundance BNPstrimp compounds when they performed a good separation in liquid chromatography. The quantitative results were comparable and traceable. This approach is a promising tool for BNP product quality and safety assessment.

Ultrabright Fluorescence Readout of an Inkjet-Printed Immunoassay Using Plasmonic Nanogap Cavities

Fluorescence-based microarrays are promising diagnostic tools due to their high throughput, small sample volume requirements, and multiplexing capabilities. However, their low fluorescence output has limited their implementation for in vitro diagnostics applications in point-of-care (POC) settings. Here, by integration of a sandwich immunoassay microarray within a plasmonic nanogap cavity, we demonstrate strongly enhanced fluorescence which is critical for readout by inexpensive POC detectors. The immunoassay consists of inkjet-printed antibodies on a polymer brush which is grown on a gold film. Colloidally synthesized silver nanocubes are placed on top and interact with the underlying gold film creating high local electromagnetic field enhancements. By varying the thickness of the brush from 5 to 20 nm, up to a 151-fold increase in fluorescence and 14-fold improvement in the limit-of-detection is observed for the cardiac biomarker B-type natriuretic peptide (BNP) compared to the unenhanced assay, paving the way for a new generation of POC clinical diagnostics.

Predicting Adverse Events beyond Stroke and Bleeding with the ABC-Stroke and ABC-Bleeding Scores in Patients with Atrial Fibrillation: The Murcia AF Project

Background The ABC (age, biomarkers, and clinical history)-stroke and ABC-bleeding are biomarker-based scores proposed to predict stroke and bleeding, but non-specificity of biomarkers is common, predicting different clinical events at the same time. We assessed the predictive performance of the ABC-stroke and ABC-bleeding scores, for outcomes beyond ischemic stroke and major bleeding, in a cohort of atrial fibrillation (AF) patients.

Methods We included AF patients stable on vitamin K antagonists for 6 months. The ABC-stroke and ABC-bleeding were calculated and the predictive values for myocardial infarction (MI), acute heart failure (HF), a composite of cardiovascular events, and all-cause deaths were compared.

Results We included 1,044 patients (49.2% male; median age 76 [71–81] years). During 6.5 (4.3–7.9) years, there were 58 (5.6%) MIs, 98 (9.4%) acute HFs, 167 (16%) cardiovascular events, and 418 (40%) all-cause deaths. There were no differences in mean ABC-stroke and ABC-bleeding scores in patients with/without MI (p = 0.367 and p = 0.286, respectively); both scores were higher in patients with acute HF, cardiovascular events, or death (all p < 0.05). Predictive performances for the ABC-stroke and ABC-bleeding scores were similar, ranging from “poor” for MI (c-indexes ∼0.54), “moderate” for acute HF and cardiovascular events (c-indexes ∼0.60 and ∼0.64, respectively), and “good” for all-cause mortality (c-indexes > 0.70). Clinical usefulness whether assessed by ABC-stroke or ABC-bleeding was similar for various primary endpoints.

Conclusion In AF patients, the ABC-stroke and ABC-bleeding scores demonstrated similar predictive ability for outcomes beyond stroke and bleeding, including MI, acute HF, a composite of cardiovascular events, and all-cause deaths. This is consistent with nonspecificity of biomarkers that predict “sick” patients or poor prognosis overall.

Towards Point-of-Care Heart Failure Diagnostic Platforms: BNP and NT-proBNP Biosensors

Heart failure is a class of cardiovascular diseases that remains the number one cause of death worldwide with a substantial economic burden of around $18 billion incurred by the healthcare sector in 2017 due to heart failure hospitalization and disease management. Although several laboratory tests have been used for early detection of heart failure, these traditional diagnostic methods still fail to effectively guide clinical decisions, prognosis, and therapy in a timely and cost-effective manner. Recent advances in the design and development of biosensors coupled with the discovery of new clinically relevant cardiac biomarkers are paving the way for breakthroughs in heart failure management. Natriuretic neurohormone peptides, B-type natriuretic peptide (BNP) and N-terminal prohormone of BNP (NT-proBNP), are among the most promising biomarkers for clinical use. Remarkably, they result in an increased diagnostic accuracy of around 80% owing to the strong correlation between their circulating concentrations and different heart failure events. The latter has encouraged research towards developing and optimizing BNP biosensors for rapid and highly sensitive detection in the scope of point-of-care testing. This review sheds light on the advances in BNP and NT-proBNP sensing technologies for point-of-care (POC) applications and highlights the challenges of potential integration of these technologies in the clinic. Optical and electrochemical immunosensors are currently used for BNP sensing. The performance metrics of these biosensors-expressed in terms of sensitivity, selectivity, reproducibility, and other criteria-are compared to those of traditional diagnostic techniques, and the clinical applicability of these biosensors is assessed for their potential integration in point-of-care diagnostic platforms.

Towards label-free, wash-free and quantitative B-type natriuretic peptide detection for heart failure diagnosis

Current diagnostic systems used in clinical settings to detect protein biomarkers require highly trained experts, large volumes of blood samples, and long turnaround times. There is an immense need for a low-cost and accurate point-of-care-testing (POCT) device for home monitoring of protein biomarkers for global pandemics such as heart failure (HF). The integration of highly sensitive carbon nanotube (CNT) thin film (CNT-TF) impedance sensors with the electrochemical impedance spectroscopy (EIS) technique is a promising platform to actualize POCT systems for home use. Herein, we report such a system, NanoBot, which allows the label-free and wash-free detection of the HF antigen biomarker B-type natriuretic peptide (BNP) in blood plasma. The NanoBot system consists of two parts: a disposable test strip and a miniature electronic readout unit. The NanoBot exhibited reasonable accuracy and precision, a clinically relevant limit of detection (LOD) as low as 16 pg mL-1, a linear detection range from 0-4000 pg mL-1 and excellent correlation with a reference standard fluorescent immunoassay (FIA). A pilot clinical study with patient-derived blood plasma validated the NanoBot's strong performance compared to that of Alere Triage®, with an interclass correlation coefficient (ICC) of 98% and a square of correlation coefficient (CC) of 0.95. Furthermore, unlike the Alere Triage® that requires more than 250 μL of blood collected via venipuncture, the NanoBot only requires 50 μL of blood. Collectively, the NanoBot's high sensitivity, accuracy, precision, and self-calibration characteristics signify its promising potential as a POCT platform for heart failure diagnosis in home use.

Analytical performance of a single epitope B-type natriuretic peptide sandwich immunoassay on the Minicare platform for point-of-care diagnostics

Point-of-care B-type natriuretic peptide (BNP) testing with adequate analytical performance has the potential to improve patient flow and provide primary care givers with easy-to-use advanced diagnostic tools in the management of heart failure. We present the analytical evaluation of the Minicare BNP immunoassay under development on the Minicare I-20 platform for point-of-care testing. Analytical performance was evaluated using EDTA venous whole blood, EDTA plasma and capillary whole blood. Method comparison with a lab-testing system was performed using samples from 187 patients. Normal values were determined based on 160 healthy adults, aging from 19 to 70 years. Limit of blank (LoB), limit of detection (LoD) were determined to be 3.3 ng/L, 5.8 ng/L. Limit of quantitation (LoQ) in whole blood at 20% and 10% coefficient of variation (CV) was found < 9 ng/L and <30 ng/L respectively without significant differences between EDTA whole blood and EDTA plasma. Total CV was found to be from 6.7% to 9.7% for BNP concentrations between 92.6 and 3984 ng/L. The sample type comparison study demonstrated correlation coefficients between 0.97 and 0.99 with slopes between 1.03 and 1.09 between the different samples. Method comparison between Minicare BNP and Siemens ADVIA Centaur BNP demonstrated a correlation coefficient of 0.92 with a slope of 1.06. The 97.5% URL of a healthy population was calculated to be 72.6 ng/L. The Minicare BNP assay is a robust, easy-to-use and sensitive test for rapid determination of BNP concentrations that can be used in a near-patient setting.

BNP and NT-proBNP as Diagnostic Biomarkers for Cardiac Dysfunction in Both Clinical and Forensic Medicine

Currently, brain natriuretic peptide (BNP) and N-terminal proBNP (NT-proBNP) are widely used as diagnostic biomarkers for heart failure (HF) and cardiac dysfunction in clinical medicine. They are also used as postmortem biomarkers reflecting cardiac function of the deceased before death in forensic medicine. Several previous studies have reviewed BNP and NT-proBNP in clinical medicine, however, few articles have reviewed their application in forensic medicine. The present article reviews the biological features, the research and application status, and the future research prospects of BNP and NT-proBNP in both clinical medicine and forensic medicine, thereby providing valuable assistance for clinicians and forensic pathologists.

The Irreplaceable Value of Laboratory Diagnostics: Four Recent Tests that have Revolutionized Clinical Practice

There is a common perception that laboratory medicine may be occasionally perceived as neglected discipline by clinicians, and that laboratory tests may be considered ordinary commodities. Although there is still debate on the real contribution of diagnostic testing in care pathways, many clinical diagnoses cannot be made without laboratory data. In support of evidence-based added value of laboratory diagnostics, this article aims to discuss the over-reaching contribution of some recent tests to the clinical decision making, and the unquestionable role they have played in revolutionizing clinical practice. These paradigmatic tests include highly-sensitive cardiac troponin immunoassays for diagnosing non-ST elevation myocardial infarction, hemoglobin A1c for diagnosis and therapeutic management of diabetes, procalcitonin for diagnosing severe bacterial infections and improving antibiotic stewardship, along with natriuretic peptides for early diagnosing and managing heart failure. It is advisable that altogether these paradigms will help reaffirming the vital role of laboratory medicine in modern healthcare.

Electrochemical cardiovascular platforms: Current state of the art and beyond

Cardiovascular diseases (CVD) remain the leading cause of death within industrialized nations as well as an increasing cause of mortality and morbidity in many developing countries. Smoking, alcohol consumption and increased level of blood cholesterol are the main CVD risk factors. Other factors, such as the prevalence of overweight/obesity and diabetes, have increased considerably in recent decades and are indirect causes of CVD. Among CVDs, the acute coronary syndrome (ACS) represents the most common cause of emergency hospital admission. Since the prognosis of ACS is directly associated with timely initiation of revascularization, missed, misdiagnosis or late diagnosis have unfavorable medical implications. Early ACS diagnosis can reduce complications and risk of recurrence, finally decreasing the economic burden posed on the health care system as a whole. To decrease the risk of ACS and related CVDs and to reduce associated costs to healthcare systems, a fast management of patients with chest pain has become crucial and urgent. Despite great efforts, biochemical diagnostic approaches of CVDs remain difficult and controversial medical challenges as cardiac biomarkers should be rapidly released into the blood at the time of ischemia and persistent for a sufficient length of time to allow diagnostics, with tests that should be rapid, easy to perform and relatively inexpensive. Early biomarker assessments have involved testing for the total enzyme activity of aspartate aminotransferase (AST), lactate dehydrogenase (LDH) and creatine kinase (CK), which cardiac troponins being the main accepted biomarkers for diagnosing myocardial injury and acute myocardial infarction (AMI). To allow rapid diagnosis, it is necessary to replace the traditional biochemical assays by cardiac biosensor platforms. Among the numerous of possibilities existing today, electrochemical biosensors are important players as they have many of the required characteristics for point-of-care tests. Electrochemical based cardiac biosensors are highly adapted for monitoring the onset and progress of cardiovascular diseases in a fast and accurate manner, while being cheap and scalable devices. This review outlines the state of the art in the development of cardiac electrochemical sensors for the detection of different cardiac biomarkers ranging from troponin to BNP, N-terminal proBNP, and others.

Atrial Fibrillation in Heart Failure: Left Atrial Appendage Management

Atrial fibrillation is common in patients with congestive heart failure (CHF). Due to reduced left atrial appendage (LAA) emptying velocities and increased sludge formation, a higher rate of stroke and embolism are seen with CHF. Up to 50% of CHF patients are inadequately covered for stroke protection with anticoagulation, and, even while on therapy, CHF patients are at risk for failure to clear LAA or left ventricular (LV) thrombus. Device-based LAA closure (LAAC) alternatives exist. Following intracardiac device closure, an increased rate of device-related thrombus is seen in heart failure patients, which warrants further study to optimize LAAC benefits.

Analytical barriers in clinical B-type natriuretic peptide measurement and the promising analytical methods based on mass spectrometry technology

B-type natriuretic peptide (BNP) is a circulating biomarker that is mainly applied in heart failure (HF) diagnosis and to monitor disease progression. Because some identical amino acid sequences occur in the precursor and metabolites of BNP, undesirable cross-reactions are common in immunoassays. This review first summarizes current analytical methods, such as immunoassay- and mass spectrometry (MS)-based approaches, including the accuracy of measurement and the inconsistency of the results. Second, the review presents some promising approaches to resolve the current barriers in clinical BNP measurement, such as how to decrease cross-reactions and increase the measurement consistency. Specific approaches include research on novel BNP assays with higher-specificity chemical antibodies, the development of International System of Units (SI)-traceable reference materials, and the development of structure characterization methods based on state-of-the-art ambient and ion mobility MS technologies. The factors that could affect MS analysis are also discussed, such as biological sample cleanup and peptide ionization efficiency. The purpose of this review is to explore and identify the main problems in BNP clinical measurement and to present three types of approaches to resolve these problems, namely, materials, methods and instruments. Although novel approaches are proposed here, in practice, it is worth noting that the BNP-related peptides including unprocessed proBNP were all measured in clinical BNP assays. Therefore, approaches that aimed to measure a specific BNP or proBNP might be an effective way for the standardization of a particular BNP form measurement, instead of the standardization of “total” immunoreactive BNP assays in clinical at present.

Electrochemical Aptamer-Based Biosensors for the Detection of Cardiac Biomarkers

Rapid and accurate diagnostic technologies for early-state identification of cardiovascular abnormalities have become of high importance to prevent and attenuate their progression. The capability of biosensors to determine an increase in the concentration of cardiovascular protein biomarkers in circulating blood immediately after a myocardial infarction makes them ideal point-of-care platforms and alternative approaches to electrocardiograms, chest X-rays, and different laboratory-based immunoassays. We report here a generic approach toward multianalyte sensing platforms for cardiac biomarkers by developing aptamer-based electrochemical sensors for brain natriuretic peptide (BNP-32) and cardiac troponin I (cTnI). For this, commercial gold-based screen-printed electrodes were modified electrophoretically with polyethyleneimine/reduced graphene oxide films. Covalent grafting of propargylacetic acid integrates propargyl groups onto the electrode to which azide-terminated aptamers can be immobilized using Cu(I)-based "click" chemistry. To ensure low biofouling and high specificity, cardiac sensors were modified with pyrene anchors carrying poly(ethylene glycol) units. In the case of BNP-32, the sensor developed has a linear response from 1 pg mL^-1 to 1 μg mL^-1 in serum; for cTnI, linearity is observed from 1 pg mL^-1 to 10 ng mL^-1 as demanded for early-stage diagnosis of heart failure. These electrochemical aptasensors represent a step further toward multianalyte sensing of cardiac biomarkers.

Impact of B-Type Natriuretic Peptide Level on Risk Stratification of Thromboembolism and Death in Patients With Nonvalvular Atrial Fibrillation - The Hokuriku-Plus AF Registry

BACKGROUND

B-type natriuretic peptide (BNP) may be a predictor of stroke risk in patients with nonvalvular atrial fibrillation (NVAF); because heart failure is associated with the incidence of stroke in AF patients. However, limited data exist regarding the association between BNP at baseline and risks of thromboembolic events (TE) and death in NVAF patients. Methods and Results: We prospectively studied 1,013 NVAF patients (725 men, 72.8±9.7 years old) from the Hokuriku-plus AF Registry to determine the relationship between BNP at baseline and prognosis among Japanese NVAF patients. During the follow-up period (median, 751 days); 31 patients experienced TE and there were 81 cases of TE/all-cause death. For each endpoint we constructed receiver-operating characteristic curves that gave cutoff points of BNP for TE (170 pg/mL) and TE/all-cause death (147 pg/mL). Multivariate analysis with the Cox-proportional hazards model indicated that high BNP was significantly associated with risks of TE (hazard ratio [HR] 3.86; 95% confidence interval [CI] 1.83-8.67; P=0.0003) and TE/all-cause death (HR 2.27; 95% CI 1.45-3.56; P=0.0003). Based on the C-index and net reclassification improvement, the addition of BNP to CHA2DS2-VASc statistically improved the prediction of TE.

CONCLUSIONS

In a real-world cohort of Japanese NVAF patients, high BNP was significantly associated with TE and death. Plasma BNP might be a useful biomarker for these adverse clinical events.

An electrochemical immunosensor for brain natriuretic peptide prepared with screen-printed carbon electrodes nanostructured with gold nanoparticles grafted through aryl diazonium salt chemistry

A sensitive amperometric immunosensor has been prepared by immobilization of capture antibodies onto gold nanoparticles (AuNPs) grafted on a screen-printed carbon electrode (SPCE) through aryl diazonium salt chemistry using 4-aminothiophenol (AuNPs-S-Phe-SPCE). The immunosensor was designed for the accurate determination of clinically relevant levels of B-type natriuretic peptide (BNP) in human serum samples. The nanostructured electrochemical platform resulted in an ordered layer of AuNPs onto SPCEs which combined the advantages of high conductivity and improved stability of immobilized biomolecules. The resulting disposable immunosensor used a sandwich type immunoassay involving a peroxidase-labeled detector antibody. The amperometric transduction was carried out at -0.20V (vs the Ag pseudo-reference electrode) upon the addition of hydroquinone (HQ) as electron transfer mediator and H₂O₂ as the enzyme substrate. The nanostructured immunosensors show a storage stability of at least 25 days, a linear range between 0.014 and 15ngmL^-1, and a LOD of 4pgmL^-1, which is 100 times lower than the established cut-off value for heart failure (HF) diagnosis. The performance of the immunosensor is advantageously compared with that provided with immunosensors prepared by grafting SPCE with p-phenylendiamine (H₂N-Phe-SPCE) and attaching AuNPs by immersion into an AuNPs suspension or by electrochemical deposition, as well as with immunosensors constructed using commercial AuNPs-modified SPCEs. The developed immunosensor was applied to the successful analysis of human serum from heart failure (HF) patients upon just a 10-times dilution as sample treatment.

Anemia considerations when assessing natriuretic peptide levels in ED patients

INTRODUCTION

The incidence of heart failure (HF) has reached epidemic levels in western populations, and the majority of these patients are admitted to hospitals through the emergency department (ED). We aimed to aid clinicians assessing natriuretic peptide (NP) levels in cases with suspected HF. In this study, we investigated the effect of anemia on amino-terminal pro-BNP (NT-proBNP) and on B-type natriuretic peptide (BNP) levels.

METHODS

This retrospective study examined patients who were admitted to the ED with suspected HF. After admission, the treating physician requested complete blood count and creatinine tests with NT-proBNP (n=2.637) or BNP (n=11.159). The exclusion criteria were used to minimize the factors that could affect the NT-proBNP and BNP results. We examined the data using the Mann-Whitney U test, Chi-square test, Spearman correlation test, and multivariate linear regression analyses.

RESULTS

The NT-proBNP and BNP levels were statistically higher in the groups with anemia (p=0.016 and p=0.009, respectively). There was a statistically significant negative correlation between hemoglobin and NP levels (r=-0.272, p<0.001 for NT-proBNP and r=-0.179, p<0.001 for BNP). The results indicated that advanced age and low hemoglobin levels were significantly associated with the increase in NT-proBNP (p=0.024 and p=0.004, respectively). Advanced age, low hemoglobin and low GFR-MDRD levels were significantly associated with the increase in BNP (p<0.001, p=0.002 and p=0.013, respectively).

DISCUSSION

The data suggest that clinicians examining patients admitted to the ED with suspected HF should consider that anemia could lead to increases in NT-proBNP and BNP levels.