Ventricular expression of brain natriuretic peptide in hypertrophic cardiomyopathy

Receptor interacting protein kinase-3 mediates both myopathy and cardiomyopathy in preclinical animal models of Duchenne muscular dystrophy

BACKGROUND

Duchenne muscular dystrophy (DMD) is a progressive muscle degenerative disorder, culminating in a complete loss of ambulation, hypertrophic cardiomyopathy and a fatal cardiorespiratory failure. Necroptosis is the form of necrosis that is dependent upon the receptor-interacting protein kinase (RIPK) 3; it is involved in several inflammatory and neurodegenerative conditions. We previously identified RIPK3 as a key player in the acute myonecrosis affecting the hindlimb muscles of the mdx dystrophic mouse model. Whether necroptosis also mediates respiratory and heart disorders in DMD is currently unknown.

METHODS

Evidence of activation of the necroptotic axis was examined in dystrophic tissues from Golden retriever muscular dystrophy (GRMD) dogs and R-DMDdel52 rats. A functional assessment of the involvement of necroptosis in dystrophic animals was performed on mdx mice that were genetically depleted for RIPK3. Dystrophic mice aged from 12 to 18 months were analysed by histology and molecular biology to compare the phenotype of muscles from mdxRipk3+/+ and mdxRipk3-/- mice. Heart function was also examined by echocardiography in 40-week-old mice.

RESULTS

RIPK3 expression in sartorius and biceps femoris muscles from GRMD dogs positively correlated to myonecrosis levels (r = 0.81; P = 0.0076). RIPK3 was also found elevated in the diaphragm (P ≤ 0.05). In the slow-progressing heart phenotype of GRMD dogs, the phosphorylated form of RIPK1 at the Serine 161 site was dramatically increased in cardiomyocytes. A similar p-RIPK1 upregulation characterized the cardiomyocytes of the severe DMDdel52 rat model, associated with a marked overexpression of Ripk1 (P = 0.007) and Ripk3 (P = 0.008), indicating primed activation of the necroptotic pathway in the dystrophic heart. MdxRipk3-/- mice displayed decreased compensatory hypertrophy of the heart (P = 0.014), and echocardiography showed a 19% increase in the relative wall thickness (P < 0.05) and 29% reduction in the left ventricle mass (P = 0.0144). Besides, mdxRipk3-/- mice presented no evidence of a regenerative default or sarcopenia in skeletal muscles, moreover around 50% less affected by fibrosis (P < 0.05).

CONCLUSIONS

Our data highlight molecular and histological evidence that the necroptotic pathway is activated in degenerative tissues from dystrophic animal models, including the diaphragm and the heart. We also provide the genetic proof of concept that selective inhibition of necroptosis in dystrophic condition improves both histological features of muscles and cardiac function, suggesting that prevention of necroptosis is susceptible to providing multiorgan beneficial effects for DMD.

Left ventricular strain patterns and their relationships with cardiac biomarkers in hypertrophic cardiomyopathy patients with preserved left ventricular ejection fraction

Aims

This study aims to assess left ventricular (LV) function in hypertrophic cardiomyopathy (HCM) patients with preserved left ventricular ejection fraction (LVEF) by LV strain patterns based on cardiac magnetic resonance feature tracking (CMR-FT) and to explore the relationships between LV strain patterns and cardiac biomarkers in these patients, such as cardiac troponin (cTnT) and N-terminal prohormone of the brain natriuretic peptide (NT-proBNP).

Methods

A total of 64 HCM patients with preserved LVEF and 33 healthy people were included in this study. All subjects underwent contrast-enhanced CMR, and all patients took blood tests for cTnT and NT-proBNP during hospitalization.

Results

Despite the absence of a significant difference in LVEF between HCM patients and healthy controls, almost all global and segmental strains in radial, circumferential, and longitudinal directions in the HCM group deteriorated significantly as compared to controls (p < 0.05). Moreover, some global and segmental strains correlated significantly with NT-proBNP and cTnT in HCM patients, and the best correlations were global radial strain (GRS) (r = -0.553, p < 0.001) and mid-ventricular radial strain (MRS) (r = -0.582, p < 0.001), respectively, with a moderate correlation. The receiver operating characteristic (ROC) results showed that among the LV deformation parameters, GRS [area under the curve (AUC), 0.76; sensitivity, 0.49; specificity, 1.00], MRS (AUC, 0.81; sensitivity, 0.77; specificity, 0.79) demonstrated greater diagnostic accuracy to predict elevated NT-proBNP, and abnormal cTnT, respectively. Their cut-off values were 21.17 and 20.94%, respectively. Finally, all global strains demonstrated moderate, good, and excellent intra- and inter-observer reproducibility.

Conclusion

LV strain patterns can be used to assess the subclinical cardiac function of HCM patients on the merit of being more sensitive than LVEF. In addition, LV strain patterns can detect serious HCM patients and may be helpful to non-invasively predict elevated NT-proBNP and cTnT.

Association of NT-proBNP and hs-cTnT with Imaging Markers of Diastolic Dysfunction and Focal Myocardial Fibrosis in Hypertrophic Cardiomyopathy

Serum biomarkers such as N-terminal prohormone of the brain natriuretic peptide (NT-proBNP) and cardiac troponins are elevated in patients with hypertrophic cardiomyopathy (HCM). At present, it is not clear if these markers are associated with distinct clinical alterations in HCM, such as left ventricular hypertrophy, outflow tract obstruction, myocardial fibrosis and/or diastolic dysfunction (DD), which are associated with adverse cardiovascular outcome. Here we evaluate the association of NT-proBNP and high sensitivity cardiac troponin T (hs-cTnT) to a variety of cardiac imaging parameters in HCM patients in a multivariable regression analysis. This retrospective cross-sectional study included 366 HCM patients who underwent transthoracic echocardiography (TTE), 218 of whom also obtained cardiovascular magnetic resonance (CMR) to assess focal myocardial fibrosis by LGE. Multivariable regression analyses revealed the strongest association of the DD parameters E/E′ mean and E/E′ septal with NT-proBNP (b = 0.06, 95%-CI [0.05−0.07], p < 0.001, R2 = 0.28; b = 0.08, 95%-CI [0.06−0.1], p < 0.001, R2 = 0.25) and LGE size showed the strongest association with hs-cTnT (b = 0.20, 95%-CI [0.15−0.24], p < 0.001, R2 = 0.28). This study indicates that NT-proBNP and hs-cTnT are associated with structural and functional alterations in HCM. NT-proBNP is a stronger predictor for DD, while hs-cTnT is associated with the extent of focal myocardial fibrosis. Both biomarkers might be useful in the diagnostic procedure in addition to imaging parameters.

The Time Has Come to Explore Plasma Biomarkers in Genetic Cardiomyopathies

For patients with hypertrophic cardiomyopathy (HCM), dilated cardiomyopathy (DCM) or arrhythmogenic cardiomyopathy (ACM), screening for pathogenic variants has become standard clinical practice. Genetic cascade screening also allows the identification of relatives that carry the same mutation as the proband, but disease onset and severity in mutation carriers often remains uncertain. Early detection of disease onset may allow timely treatment before irreversible changes are present. Although plasma biomarkers may aid in the prediction of disease onset, monitoring relies predominantly on identifying early clinical symptoms, on imaging techniques like echocardiography (Echo) and cardiac magnetic resonance imaging (CMR), and on (ambulatory) electrocardiography (electrocardiograms (ECGs)). In contrast to most other cardiac diseases, which are explained by a combination of risk factors and comorbidities, genetic cardiomyopathies have a clear primary genetically defined cardiac background. Cardiomyopathy cohorts could therefore have excellent value in biomarker studies and in distinguishing biomarkers related to the primary cardiac disease from those related to extracardiac, secondary organ dysfunction. Despite this advantage, biomarker investigations in cardiomyopathies are still limited, most likely due to the limited number of carriers in the past. Here, we discuss not only the potential use of established plasma biomarkers, including natriuretic peptides and troponins, but also the use of novel biomarkers, such as cardiac autoantibodies in genetic cardiomyopathy, and discuss how we can gauge biomarker studies in cardiomyopathy cohorts for heart failure at large.

Predictive values of multiple non-invasive markers for myocardial fibrosis in hypertrophic cardiomyopathy patients with preserved ejection fraction

Myocardial fibrosis assessed by late gadolinium enhancement (LGE) on cardiovascular magnetic resonance (CMR) is associated with cardiovascular outcomes in hypertrophic cardiomyopathy (HCM) patients, but little is known about the utility of non-invasive markers for detecting LGE. This study aims to explore the association between cardiac-specific biomarkers, CMR myocardial strain, left ventricular (LV) hypertrophy and LGE in HCM patients with preserved ejection fraction (EF) and investigate the predictive values of these indexes for LGE. We recruited 33 healthy volunteers and 86 HCM patients with preserved EF to undergo contrast-enhanced CMR examinations. In total, 48 of 86 HCM patients had the presence of LGE. The LGE-positive patients had significant higher serum high-sensitivity cardiac troponin I (hs-cTnI) and N-terminal pro b-type natriuretic peptide (Nt-proBNP) levels and lower global longitudinal (GLS) and circumferential (GCS) strains than the LGE-negative group. The LGE% was independently associated with the Nt-proBNP levels, GCS, LV end-diastolic maximum wall thickness (MWT) and beta-blocker treatment. In the receiver operating characteristic curve analysis, the combined parameters of Nt-proBNP ≥ 108.00 pg/mL and MWT ≥ 17.30 mm had good diagnostic performance for LGE, with a specificity of 81.25% and sensitivity of 70.00%. These data indicate that serum Nt-proBNP is a potential biomarker associated with LGE% and, combined with MWT, were useful for identifying myocardial fibrosis in HCM patients with preserved EF. Additionally, LV GCS may be a more sensitive indicator for reflecting the presence of myocardial fibrosis than GLS.

Methamphetamine induces cardiomyopathy by Sigmar1 inhibition-dependent impairment of mitochondrial dynamics and function

Methamphetamine-associated cardiomyopathy is the leading cause of death linked with illicit drug use. Here we show that Sigmar1 is a therapeutic target for methamphetamine-associated cardiomyopathy and defined the molecular mechanisms using autopsy samples of human hearts, and a mouse model of "binge and crash" methamphetamine administration. Sigmar1 expression is significantly decreased in the hearts of human methamphetamine users and those of "binge and crash" methamphetamine-treated mice. The hearts of methamphetamine users also show signs of cardiomyopathy, including cellular injury, fibrosis, and enlargement of the heart. In addition, mice expose to "binge and crash" methamphetamine develop cardiac hypertrophy, fibrotic remodeling, and mitochondrial dysfunction leading to contractile dysfunction. Methamphetamine treatment inhibits Sigmar1, resulting in inactivation of the cAMP response element-binding protein (CREB), decreased expression of mitochondrial fission 1 protein (FIS1), and ultimately alteration of mitochondrial dynamics and function. Therefore, Sigmar1 is a viable therapeutic agent for protection against methamphetamine-associated cardiomyopathy.

LPS-enhanced IGF-IIR pathway to induce H9c2 cardiomyoblast cell hypertrophy was attenuated by Carthamus tinctorius extract via IGF-IR activation

The use of herbs as alternative cardiovascular disease treatment has attracted a great deal of attention owing to their lower toxicity. Whether Carthamus tinctorius extract prevent cardiomyoblast cell hypertrophy remains unclear. The present study was performed to investigate the effect of C tinctorius extract (CTF) on rat cardiomyoblast cell H9c2 and the possible molecular mechanisms. H9c2 cells were treated with lipopolysaccharide (LPS; 2 μg/mL) for 12 hours, subsequently treated with CTF (1-25 μg/mL) The incubation continued for another 24 hours, and the cells were analyzed with actin staining assay, western blot analysis, and siRNA transfection assays. In the present study, the increased cell size induced by LPS was significantly decreased by pretreating at a concentration of 1-25 μg/mL CTF. It was found that CTF could inhibit cardiac hypertrophy induced by LPS and decrease hypertrophic proteins calcineurin, p-GATA-4, GATA-4, atrial natriuretic peptide, and B-type natriuretic peptide levels in H9c2 cells. Additionally, LPS-induced insulin-like growth factor-II receptor (IGF-IIR) hypertrophy pathway was downregulated by CTF. Moreover, IGF-IR siRNA or inhibitors both reversed the CTF effects, confirming that CTF activates IGF-1R to prevent LPS-induced H9c2 cardiomyoblast cell hypertrophy. The current findings indicate that CTF activates IGF-IR to inhibit IGF-IIR signaling pathway which resulted in reducing H9c2 cardiomyoblast cell hypertrophy induced by LPS.

High-sensitivity troponin I and B-type natriuretic peptide biomarkers for prediction of cardiovascular events in patients with coronary artery disease with and without diabetes mellitus

Background

High-sensitivity troponin I (hs-Tnl) and B-type natriuretic peptide (BNP) are promising prognostic markers for coronary artery disease (CAD). This prospective cohort study investigated whether a combination of these cardiac biomarkers with conventional risk factors would add incremental value for the prediction of secondary major adverse cardiovascular events (MACEs) in patients with CAD, with and without type 2 diabetes mellitus (T2DM).

Methods

Baseline plasma level of hs-Tnl and BNP was measured in 2275 Chinese patients with stable CAD. Patients were monitored for new-onset of MACE over a median of 51 months. Cox proportional hazard model and area under the receiver operating characteristic curve (AUC) were used to assess the association of cardiac biomarkers with MACE and their predictive values in relationship with or without T2DM.

Results

During the follow up period 402 (18%) patients experienced a new-onset MACE with hs-Tnl and BNP level significantly higher than in those without MACE. In multivariable analyses, patients with elevated hs-Tnl (hazard ratio, 1.75 [95% CI 1.41–2.17]; P < 0.001) and BNP (hazard ratio, 1.42 [95% CI 1.15–1.75]; P = 0.001) were significantly associated with an increased risk of MACE after adjustment for variables of a risk factor model of age, sex, T2DM and hypertension. The risk factor model had an AUC of 0.64 for MACE prediction. The AUC significantly increased to 0.68 by the addition of hs-Tnl to the risk factor model. Subgroup analyses showed that hs-Tnl and BNP remained significant predictors of MACE in both patients with and without T2DM in multivariable models with higher risk of MACE evident in those without T2DM. Among patients without T2DM, addition of each biomarker yielded greater predictive accuracy than in T2DM patients, with AUC further increased to 0.75 when a combination of hs-Tnl and BNP was added to the risk factor model (age, sex and hypertension).

Conclusions

Elevated hs-Tnl and BNP level are independent predictors of new-onset MACE in CAD patients, irrespective of diabetes status. Among CAD patients without T2DM, a combination of cardiac biomarkers hs-Tnl and BNP yield the greatest predictive value beyond conventional risk factors.

Genetic Ablation and Guanylyl Cyclase/Natriuretic Peptide Receptor-A: Impact on the Pathophysiology of Cardiovascular Dysfunction

Mice bearing targeted gene mutations that affect the functions of natriuretic peptides (NPs) and natriuretic peptide receptors (NPRs) have contributed important information on the pathogenesis of hypertension, kidney disease, and cardiovascular dysfunction. Studies of mice having both complete gene disruption and tissue-specific gene ablation have contributed to our understanding of hypertension and cardiovascular disorders. These phenomena are consistent with an oligogenic inheritance in which interactions among a few alleles may account for genetic susceptibility to hypertension, renal insufficiency, and congestive heart failure. In addition to gene knockouts conferring increased risks of hypertension, kidney disorders, and cardiovascular dysfunction, studies of gene duplications have identified mutations that protect against high blood pressure and cardiovascular events, thus generating the notion that certain alleles can confer resistance to hypertension and heart disease. This review focuses on the intriguing phenotypes of Npr1 gene disruption and gene duplication in mice, with emphasis on hypertension and cardiovascular events using mouse models carrying Npr1 gene knockout and/or gene duplication. It also describes how Npr1 gene targeting in mice has contributed to our knowledge of the roles of NPs and NPRs in dose-dependently regulating hypertension and cardiovascular events.

Evaluation of a sensitive cardiac troponin I assay as a screening test for the diagnosis of hypertrophic cardiomyopathy in cats

Background

Hypertrophic cardiomyopathy (HCM) is the most common cardiac disease in cats. However, most cats are not diagnosed until they develop congestive heart failure, arterial thromboembolism (ATE), or sudden cardiac death. Thus, an affordable screening test for early detection of HCM is desirable.

Hypothesis/Objectives

Evaluation of a sensitive cardiac troponin I (cTnI) assay as a screening test for HCM in cats and determination of a cutoff for its early detection.

Animals

One hundred sixty‐six client‐owned cats (male, n = 97) of various breeds were evaluated and classified using echocardiography as being healthy (n = 87), equivocal (n = 15), or having HCM (mild, n = 16; moderate, n = 10; severe, n = 34) or ATE (n = 4).

Methods

All cats were prospectively evaluated by echocardiography, and serum cTnI concentration was determined using the currently most sensitive assay (Siemens ADVIA Centaur TnI‐Ultra).

Results

The median cTnI concentration was significantly different between study groups (P < .000001). A cutoff of 0.06 ng/mL provided good discrimination between healthy cats and cats with HCM (sensitivity, 91.7%; specificity, 95.4%; area under the curve [AUC], 0.95; 95% confidence interval [CI], 0.899‐0.978). Even for asymptomatic cats with HCM, sensitivity and specificity for a cutoff of >0.06 ng/mL remained high at 87.8% and 95.4%, respectively (AUC, 0.93; 95% CI, 0.864‐0.964).

Conclusions and clinical importance

Cardiac troponin I can be used as a sensitive and specific screening test for the diagnosis of HCM in otherwise healthy cats (cutoff, >0.06 ng/mL). However, echocardiography is needed to confirm the diagnosis.

Neutrophil-Initiated Myocardial Inflammation and Its Modulation by B-Type Natriuretic Peptide: A Potential Therapeutic Target

Activation of neutrophils is a critically important component of the innate immune response to bacterial and chemical stimuli, and culminates in the “neutrophil burst”, which facilitates neutrophil phagocytosis via the release of superoxide anion radical (O₂⁻) from NADPH oxidase. Excessive and/or prolonged neutrophil activation results in substantial tissue injury and increases in vascular permeability—resulting in sustained tissue infiltration with neutrophils and monocytes, and persistent vasomotor dysfunction. Cardiovascular examples of such changes include acute and chronic systolic and diastolic heart failure (“heart failure with preserved ejection fraction”), and the catecholamine-induced inflammatory disorder takotsubo syndrome. We have recently demonstrated that B-type natriuretic peptide (BNP), acting via inhibition of activation of neutrophil NADPH oxidase, is an important negative modulator of the “neutrophil burst”, though its effectiveness in limiting tissue injury is partially lost in acute heart failure. The potential therapeutic implications of these findings, regarding the development of new means of treating both acute and chronic cardiac injury states, are discussed.

Platelet Function Analyzer 100 and Brain Natriuretic Peptide as Biomarkers in Obstructive Hypertrophic Cardiomyopathy

To test dual blood biomarkers compared with electrocardiogram (ECG) for hypertrophic cardiomyopathy (HC) screening, we performed 3 analyses and cut-point assessments. First, we measured platelet function analyzer (PFA)-100 (n = 99) and normalized B-type natriuretic peptide (BNP) or NT-proBNP (BNP/upper limit of normal [ULN], n = 92) in 64 patients with HC and 29 normal controls (NCs). Second, from the regression equation between PFA and gradient (r = 0.77), we derived estimated PFA in a population of 189 patients with functional class I HC in whom measured BNP/ULN and ECG were available, and calculated single and dual biomarker sensitivity and specificity compared with ECG. Finally, we compared BNP/ULN in class I patients based on mutation and familial history status. In 42 patients with obstructive HC versus NCs, there was a slight overlap of PFA and BNP/ULN, but for the product of PFA × BNP/ULN, there was near-complete separation of values. Among patients with class I obstructive HC, estimated PFA × BNP/ULN had a sensitivity of 93% and a specificity of 100%; in latent and nonobstructive HC, sensitivity dropped to 61% and 72%; for ECG in obstructive, latent, and nonobstructive HC, sensitivity was 71%, 34%, and 67%. Functional class I patients with positive (n = 28) and negative (n = 36) sarcomere mutations and a positive (n = 71) or a negative (n = 109) family history had significant elevations of BNP/ULN versus NC, with no between-group differences. In conclusion, PFA and BNP were highly associated with obstructive HC and could potentially be used for screening; BNP was not uniquely elevated in patients with familial versus nonfamilial or mutation-positive versus mutation-negative HC.

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

Since its discovery in 1988, B-type natriuretic peptide (BNP) has been recognized as a powerful cardiovascular biomarker for a number of disease states, specifically heart failure. Concurrent with such a discovery, much effort has been allocated to the precise monitoring of physiological BNP levels. Thus, it can be used to guide the therapy of heart failure and determine the patient's stage of disease. Thus, we discuss in this article BNP as a potent biomarker. Subsequently, we will review the progress of biosensing devices as they could be applied to monitor BNP levels as assays, benchtop biosensors and implantable biosensors. The analytical characteristics of commercially available BNP assays are presented. Still emerging as a field, we define four obstacles that present opportunity for the future development of implantable biosensor: foreign body response, sensor renewability, sensitivity and selectivity.

Standardization of BNP and NT-proBNP Immunoassays in Light of the Diverse and Complex Nature of Circulating BNP-Related Peptides

Brain natriuretic peptide (BNP) and the N-terminal fragment of the BNP precursor (NT-proBNP) are widely used as heart failure (HF) biomarkers. Since the discovery of BNP in 1988, much effort has been allocated to the precise detection of BNP and NT-proBNP levels for reliable HF diagnostics. As a result, measurements of these biomarkers are globally accepted and used in clinical practice for the diagnosis of acute and chronic HF, risk stratification, and monitoring response to therapy. Several immunoassays specific for BNP and NT-proBNP are currently commercially available. Recent comparative studies show that there are marked differences between different BNP and NT-proBNP assays and platforms, and the results of measurements are not comparable enough. The lack of equivalence between the assays complicates the interpretation of the results and renders the cut-off points for diagnostic decisions to be method dependent. Presently, there is no agreement on what kind of BNP or NT-proBNP standard should be used for calibration, and a certified reference material as well as reference measurement procedures are lacking. The aim of this chapter is to summarize the available data on the complex nature of BNP-related peptides, specificity for existing BNP and NT-proBNP immunoassays, and to discuss potential approaches for standardization of BNP and NT-proBNP measurements.

Urinary NT-proBNP levels and echocardiographic parameters for patent ductus arteriosus

OBJECTIVE

Patent ductus arteriosus (PDA) is common in preterm infants and is associated with significant morbidities. B type natriuretic peptide (BNP) is synthesized in the ventricles secondary to volume overload and excreted as urinary N-terminal pro-brain natriuretic peptide (NT-proBNP).

STUDY DESIGN

We report an observational prospective study of 64 preterm infants with birth weight ⩽1000 g. Echocardiographic parameters were obtained from clinical echocardiograms performed in the first week of life. Urinary NT-proBNP/creatinine ratios (pg mg^-1) were measured on the same day of the echocardiograms.

RESULTS

Infants with medium to large PDA (n=39) had significantly higher NT-proBNP/creatinine levels compared with infants with small PDA (n=10) (median (IQ range): 2333 (792-6166) vs 714 (271-1632) pg mg^-1, P=0.01) and compared with infants with no PDA (n=15) (2333 (792-6166) vs 390 (134-1085) pg mg^-1, P=0.0003). Urinary NT-proBNP/creatinine ratios were significantly lower post treatment if PDA closed (n=17), P=0.001 or if PDA became smaller after treatment (n=9), P=0.004. Urinary NT-proBNP/creatinine levels correlated with ductal diameter (P⩽0.0001), but not with LA/Ao ratio (P=0.69) or blood flow velocity through the ductus (P=0.06).

CONCLUSION

Our findings indicate that there is a positive correlation between ductal diameter and urinary NT-proBNP in preterm infants.

Higher copeptin levels are associated with worse outcome in patients with hypertrophic cardiomyopathy

BACKGROUND

Correlation of increased copeptin levels with various cardiovascular diseases has been described. The clinical use of copeptin levels in patients with hypertrophic cardiomyopathy (HCM) has not been investigated before.

HYPOTHESIS

In this study, we aimed to investigate the prognostic value of copeptin levels in patients with hypertrophic cardiomyopathy (HCM).

METHODS

HCM was defined as presence of left ventricular wall thickness ≥15 mm in a subject without any concomitant disease that may cause left ventricular hypertrophy. Levels of copeptin and plasma N-terminal probrain natriuretic peptide (NT-proBNP) were evaluated prospectively in 24 obstructive HCM patients, 36 nonobstructive HCM patients, and 36 age- and sex-matched control subjects. Blood samples were collected in the morning between 7 and 9 am after overnight fasting. Patients were followed for 24 months. Hospitalization with diagnosis of heart failure/arrhythmia, implantable cardioverter-defibrillator implantation, and cardiac mortality were accepted as adverse cardiac events.

RESULTS

Copeptin and NT-proBNP levels were higher in the HCM group compared with controls (14.1 vs 8.4 pmol/L, P < 0.01; and 383 vs 44 pg/mL, P < 0.01, respectively). Copeptin and NT-proBNP levels were higher in the obstructive HCM subgroup compared with the nonobstructive HCM subgroup (18.3 vs 13.1 pmol/L, P < 0.01; and 717 vs 223 pg/mL, P < 0.01, respectively). In multivariable logistic regression analysis, copeptin and NT-proBNP levels remained as independent predictors of heart failure (P < 0.01 for both) and adverse cardiac events (P < 0.01 for both).

CONCLUSIONS

Copeptin and NT-proBNP levels were significantly higher in patients with obstructive HCM, and higher levels were associated with worse outcome.

Clinical utility of natriuretic peptides and troponins in hypertrophic cardiomyopathy

The diagnosis of hypertrophic cardiomyopathy (HCM) is based on clinical, echocardiographic and in some cases genetic findings. However, prognostication remains limited except in the subset of patients with high-risk indicators for sudden cardiac death. Additional methods are needed for risk stratification and to guide clinical management in HCM. We reviewed the available data regarding natriuretic peptides and troponins in HCM. Plasma levels of natriuretic peptides, and to a lesser extent serum levels of troponins, correlate with established disease markers, including left ventricular thickness, symptom status, and left ventricular hemodynamics by Doppler measurements. As a reflection of left ventricular filling pressure, natriuretic peptides may provide an objective measure of the efficacy of a specific therapy. Both natriuretic peptides and troponins predict clinical risk in HCM independently of established risk factors, and their prognostic power is additive. Routine measurement of biomarker levels therefore may be useful in the clinical evaluation and management of patients with HCM.

Predictive Values of N-Terminal Pro-B-Type Natriuretic Peptide and Cardiac Troponin I for Myocardial Fibrosis in Hypertrophic Obstructive Cardiomyopathy

Background

Both high-sensitivity cardiac troponin T and B-type natriuretic peptide are useful in detecting myocardial fibrosis, as determined by late gadolinium enhancement (LGE) cardiovascular magnetic resonance (CMR), in patients with non-obstructive hypertrophic cardiomyopathy. However, their values to predict myocardial fibrosis in hypertrophic obstructive cardiomyopathy (HOCM) remain unclear. We investigated the role of N-Terminal Pro-B-Type Natriuretic Peptide (NT-proBNP) and cardiac troponin I (cTnI) to identify LGE-CMR in patients with HOCM.

Methods

Peripheral concentrations of NT-proBNP and cTnI were determined in patients with HOCM (n = 163; age = 47.2 ± 10.8 years; 38.7% females). Contrast-enhanced CMR was performed to identify and quantify myocardial fibrosis.

Results

LGE was detected in 120 of 163 patients (73.6%). Patients with LGE had significantly higher levels of NT-proBNP and cTnI than those without LGE (1386.2 [904.6–2340.8] vs. 866.6 [707.2–1875.2] pmol/L, P = 0.003; 0.024 [0.010–0.049] vs. 0.010 [0.005–0.021] ng/ml, P <0.001, respectively). The extent of LGE was positively correlated with log cTnI (r = 0.371, P <0.001) and log NT-proBNP (r = 0.211, P = 0.007). On multivariable analysis, both log cTnI and maximum wall thickness (MWT) were independent predictors of the presence of LGE (OR = 3.193, P = 0.033; OR = 1.410, P < 0.001, respectively), whereas log NT-proBNP was not. According to the ROC curve analysis, combined measurements of MWT ≥21 mm and/or cTnI ≥0.025ng/ml indicated good diagnostic performance for the presence of LGE, with specificity of 95% or sensitivity of 88%.

Conclusions

Serum cTnI is an independent predictor useful for identifying myocardial fibrosis, while plasma NT-proBNP is only associated with myocardial fibrosis on univariate analysis. Combined measurements of serum cTnI with MWT further improve its value in detecting myocardial fibrosis in patients with HOCM.

Prognostic values of highly sensitive cardiac troponin T and B-type natriuretic peptide for clinical features in hypertrophic obstructive cardiomyopathy: a cross-sectional study

OBJECTIVES

Although B-type natriuretic peptide (BNP) and highly sensitive cardiac troponin T (cTnT) are useful for the evaluation of clinical features in various cardiovascular diseases, there are comparatively few data regarding the utility of these parameters in patients with hypertrophic obstructive cardiomyopathy (HOCM). The goal of this study was to assess the association between BNP, cTnT and clinical parameters in patients with HOCM.

DESIGN

Cross-sectional survey

SETTINGS

The relationship between BNP, cTnT and clinical end points and echocardiographic data was investigated.

PARTICIPANTS

This study included 102 consecutive outpatients with HOCM who were clinically stable.

RESULTS

BNP was significantly associated with both maximum left ventricular (LV) wall thickness (r=0.28; p=0.003), and septal peak early transmitral filling velocity/peak early diastolic mitral annulus velocity (r=0.51; p=0.0001). No statistically significant associations were seen between cTnT and any echocardiographic parameters, but the presence of atrial fibrillation (AF) was associated with a high level of cTnT (p=0.01).

CONCLUSIONS

BNP is useful for monitoring clinical parameters and as a reflection of both LV systolic/diastolic function and increased LV pressure in patients with HOCM. A high level of serum cTnT is associated with the presence of AF.

Prognostic value of N-terminal pro-brain natriuretic Peptide in outpatients with hypertrophic cardiomyopathy

In hypertrophic cardiomyopathy, the plasma levels of N-terminal pro-brain natriuretic peptide (NT-proBNP) correlate with functional capacity. However, their prognostic relevance remains unresolved. We followed up 183 stable outpatients with hypertrophic cardiomyopathy (age 50 ± 17 years, 64% men) for 3.9 ± 2.8 years after NT-proBNP measurement. The primary end point included cardiovascular death, heart transplantation, resuscitated cardiac arrest, and appropriate implantable cardioverter-defibrillator intervention. The secondary end point (SE) included heart failure-related death or hospitalization, progression to end-stage disease, and stroke. The median NT-proBNP level was 615 pg/ml (intertertile range 310 to 1,025). The incidence of the primary end point in the lower, middle, and upper tertiles was 0%, 1.3%, and 2.1% annually, respectively (overall p = 0.01). On multivariate analysis, the only independent predictors of the primary end point were NT-proBNP (hazard ratio for log-transformed values 5.8, 95% confidence interval 1.07 to 31.6; p = 0.04) and a restrictive left ventricular filling pattern (hazard ratio 5.19, 95% confidence interval 1.3 to 21.9; p = 0.02). The NT-proBNP cutoff value of 810 pg/ml had the best sensitivity for the primary end point (88%), but the specificity was low (61%). The incidence of the SE in the lower, middle, and upper NT-proBNP tertiles was 4.6%, 12.0%, and 11.2% annually, respectively (overall p = 0.001). An NT-proBNP level of <310 pg/ml was associated with a 75% reduction in the rate of SE compared with a level of ≥310 pg/ml (hazard ratio 0.25, 95% confidence interval 0.11 to 0.57; p = 0.001), independent of age, left ventricular outflow tract obstruction, or atrial fibrillation. In conclusion, in stable outpatients with hypertrophic cardiomyopathy, plasma NT-proBNP proved a powerful independent predictor of death and heart failure-related events. Although the positive predictive accuracy of an elevated NT-proBNP level was modest, low values reflected true clinical stability, suggesting the possibility of avoiding or postponing aggressive treatment options.

Genetics of hypertrophic cardiomyopathy

PURPOSE OF REVIEW

Hypertrophic cardiomyopathy (HCM), the most common inherited cardiac disorder, exhibits remarkable genetic and clinical heterogeneity. This manuscript reviews recent discoveries of disease-causing genes and their clinical consequences, and provides an overview of research that aims to elucidate how HCM ensues from a single-nucleotide mutation.

RECENT FINDINGS

The spectrum of genes that are mutated in HCM has expanded. In combination with newly developed sequencing technologies, there are now robust strategies for gene-based diagnosis in HCM. Understanding the molecular pathophysiology of HCM has emerged from the study of genetically engineered animal models of disease, and new data indicate important roles for altered intracellular Ca²⁺ regulation and oxidative stress. Pharmacologic strategies to normalize these processes show promise in attenuating HCM in experimental models.

SUMMARY

The current repertoire of HCM genes allows effective gene-based diagnosis, information that enables accurate assessment of disease risk in family members, and provides some insight into clinical course. From mechanistic insights gleaned from fundamental investigations of experimental HCM models, novel therapeutic targets that may provide new benefits for HCM patients have surfaced.

Cardiovascular biology of the incretin system

Glucagon-like peptide-1 (GLP-1) is an incretin hormone that enhances glucose-stimulated insulin secretion and exerts direct and indirect actions on the cardiovascular system. GLP-1 and its related incretin hormone, glucose-dependent insulinotropic polypeptide, are rapidly inactivated by the enzyme dipeptidyl peptidase 4 (DPP-4), a key determinant of incretin bioactivity. Two classes of medications that enhance incretin action, GLP-1 receptor (GLP-1R) agonists and DPP-4 inhibitors, are used for the treatment of type 2 diabetes mellitus. We review herein the cardiovascular biology of GLP-1R agonists and DPP-4 inhibitors, including direct and indirect effects on cardiomyocytes, blood vessels, adipocytes, the control of blood pressure, and postprandial lipoprotein secretion. Both GLP-1R activation and DPP-4 inhibition exert multiple cardioprotective actions in preclinical models of cardiovascular dysfunction, and short-term studies in human subjects appear to demonstrate modest yet beneficial actions on cardiac function in subjects with ischemic heart disease. Incretin-based agents control body weight, improve glycemic control with a low risk of hypoglycemia, decrease blood pressure, inhibit the secretion of intestinal chylomicrons, and reduce inflammation in preclinical studies. Nevertheless, there is limited information on the cardiovascular actions of these agents in patients with diabetes and established cardiovascular disease. Hence, a more complete understanding of the cardiovascular risk to benefit ratio of incretin-based therapies will require completion of long-term cardiovascular outcome studies currently underway in patients with type 2 diabetes mellitus.

Variability of NT-proBNP and its relationship with inflammatory status in patients with stable essential hypertension: a 2-year follow-up study

BACKGROUND

The variability of NT-proBNP levels has been studied in heart failure, yet no data exist on these changes over time in hypertensive patients. Furthermore, studies on the relationship between natriuretic peptides and inflammatory status are limited.

METHODOLOGY/PRINCIPAL FINDINGS

220 clinically and functionally asymptomatic stable patients (age 59 ± 13, 120 male) out of 252 patients with essential hypertension were followed up, and NT-proBNP was measured at baseline, 12 and 24 months. No differences in NT-proBNP were found with respect to the basal stage in the hypertrophic group, but significant changes were found in non-hypertrophic subjects. The reproducibility of NT-proBNP measurements was better in patients with hypertrophy than in the non-hypertrophic group for the three intervals (stage I-basal; stage II-stage I; stage II-basal) with a reference change value of 34%, 35% and 41%, respectively, in the hypertrophic group. A more elevated coefficient of correlation was obtained in the hypertrophic group than in patients without hypertrophy: basal versus stage I (r = 0.79, p < 0.0001 and r = 0.59, p < 0.0001) and stage I versus stage II (r = 0.86, p < 0.0001 and r = 0.56, p < 0.0001). Finally, levels of NT-proBNP significantly correlated with sTNF-R1 (p < 0.0001) and IL-6 (p < 0.01) during follow-up. A multivariate linear regression analysis showed that sTNF-R1 is an independent factor of NT-proBNP.

CONCLUSIONS/SIGNIFICANCE

This work shows that there is good stability in NT-proBNP levels in a follow-up study of asymptomatic patients with stable hypertension and left ventricular hypertrophy. As a consequence, assessment of NT-proBNP concentrations may be a useful tool for monitoring the follow-up of hypertensive patients with hypertrophy. Measured variations in peptide levels, exceeding 35% in a 12-month follow-up and 41% in a 24-month follow-up, may indicate an increase in cardiovascular risk, and therefore implies adjustment in the medical treatment. In addition, this study shows a link between neurohormonal and inflammatory activation in these patients.

Degree and distribution of left ventricular hypertrophy as a determining factor for elevated natriuretic peptide levels in patients with hypertrophic cardiomyopathy: insights from cardiac magnetic resonance imaging

Whether the left ventricular (LV) mass index (LVMI) and LV volumetric parameters are associated independently with natriuretic peptide levels is unclear in hypertrophic cardiomyopathy (HCM). Therefore, we investigated which parameters have an independent relationship with N-terminal pro-B type natriuretic peptide (NT-proBNP) levels in HCM patients using echocardiography and cardiac magnetic resonance imaging (CMR). A total of 103 patients with HCM (82 men, age 53 ± 12 years) were evaluated. Echocardiographic evaluations included left atrial volume index (LAVI) and early diastolic mitral inflow E velocity to early annular Ea velocity ratio (E/Ea). LVMI, maximal wall thickness and LV volumetric parameters were measured using CMR. The median value of NT-proBNP level was 387.0 pg/ml. The mean NT-proBNP level in patients with non-apical HCM (n = 69; 36 patients with asymmetric septal hypertrophy, 11 with diffuse, and 22 with mixed type) was significantly higher than in those with apical HCM (n = 34, P < 0.001). NT-proBNP level was negatively correlated with LV end-diastolic volume (LVEDV) (r = -0.263, P = 0.007) and positively with LVMI (r = 0.225, P = 0.022) and maximal wall thickness (r = 0.495, P < 0.001). Among the echocardiographic variables, LAVI (r = 0.492, P < 0.001) and E/Ea (r = 0.432, P < 0.001) were correlated with NT-proBNP. On multivariable analysis, non-apical HCM, increased maximal wall thickness and LAVI were independently related with NT-proBNP. Severity of LV hypertrophy and diastolic parameters might be important in the elevation of NT-proBNP level in HCM. Therefore, further evaluation of these parameters in HCM might be warranted.

The diagnostic significance of the plasma N-terminal pro-B-type natriuretic Peptide concentration in asymptomatic cats with cardiac enlargement

We evaluated the diagnostic significance of the N-terminal pro-B-type natriuretic peptide (NT-proBNP) concentration in asymptomatic cats with cardiac enlargement. The plasma NT-proBNP concentration was measured in 21 clinically healthy control cats, and 67 asymptomatic cats with cardiac enlargement defined as end-diastolic interventricular septum thickness (IVSd) and/or diastolic left ventricular posterior wall thickness (LVPWd) >0.6 cm, vertebla heart scale (VHS) >7.8, and/or left atria/aorta ratio (LA/Ao) >1.5. The plasma NT-proBNP concentration in the asymptomatic cats with cardiac enlargement (median: 662.0, range: 24.0-2,449.0 pmol/l) was significantly higher than that in the controls (24.0, 24.0-95.0 pmol/l, P<0.001). The plasma NT-proBNP concentration was significantly correlated with the VHS, LA/Ao, IVSd and LVPWd (r=0.578, P<0.001; r=0.462, P<0.001; r=0.563, P<0.001; and r=0.764, P<0.001, respectively). Receiver operating characteristic analysis showed a cut-off value of 95.0 pmol/l for the detection of asymptomatic cats with cardiac enlargement, sensitivity and specificity of 88.1 and 100%, respectively, and an area under the curve of 0.971. These results suggest that the determination of the plasma NT-proBNP concentration can be a useful screening test for asymptomatic cats with cardiac enlargement.

Utility of measuring plasma N-terminal pro-brain natriuretic peptide in detecting hypertrophic cardiomyopathy and differentiating grades of severity in cats

BACKGROUND

Cats with hypertrophic cardiomyopathy (HCM) often have no clinical signs or subtle signs. Measurement of N-terminal pro-brain natriuretic peptide (NT-proBNP) has been demonstrated in people to be highly specific for heart disease and also correlates with severity of HCM. NT-proBNP may also be valuable in detecting and grading HCM in cats, but results to date have been equivocal.

OBJECTIVES

The aims of this study were to evaluate NT-proBNP as a screening test for diagnosis of HCM in cats and determine an appropriate cut-off value and to determine if NT-proBNP concentrations correlated with severity of HCM in cats.

METHODS

Plasma NT-proBNP concentrations were measured in 201 cats using an ELISA designed for use in cats. Cats were classified using echocardiography as clinically healthy controls (n=99) or cats with equivocal (n=9), mild (n=15), moderate (n=17), or severe (n=61) HCM.

RESULTS

NT-proBNP concentrations (median; 25th-75th interquartile percentiles) in mildly (216.1; 87.6-392.5 pmol/L), moderately (282.7; 131.9-466.6 pmol/L), and severely (839.5; 655.3-1046.4 pmol/L) affected cats were significantly higher than those in healthy controls (18.9; 3.4-62.4 pmol/L). Concentrations in severely affected cats were significantly higher than in cats from other HCM groups. There was no significant difference between mild and moderate HCM. Cut-off values >49 pmol/L had a sensitivity of 97.8% and specificity of 66.7%; >100 pmol/L had a sensitivity of 92.4% and specificity of 93.9%; and >150 pmol/L had a sensitivity of 88% and a specificity of 100%.

CONCLUSIONS

NT-proBNP with a cut-off value of >100 pmol/L was useful in detecting even mild HCM. Cats with increased NT-proBNP concentrations should be examined by echocardiography.

Correlation between serum cardiac markers and myocardial infarct size quantified by myocardial perfusion imaging in patients with hypertrophic cardiomyopathy after alcohol septal ablation

Myocardial infarct (MI) size is a well-established prognostic marker but the association of serum markers with MI size, as measured by myocardial perfusion imaging (MPI), has not been well studied in patients with hypertrophic cardiomyopathy (HC) after alcohol septal ablation (ASA). Creatine kinase (CK), CK-MB, troponin I, and brain natriuretic peptide were measured before and at multiple points after ASA in patients with HC and were correlated with MI size measured by MPI. MPI at rest was performed in 54 patients with HC at a median of 2 days after ASA. CK, CK-MB, and troponin I increased after ASA to peak levels at 12 hours and their cumulative levels (area under the curve) showed significant correlation with size of MI by MPI (r = 0.544, 0.408, and 0.477, p <0.001, 0.003, and 0.001, respectively). The best marker was level of CK at 12 hours (r = 0.609, p <0.0001) after ASA. Brain natriuretic peptide level did not change significantly after ASA (p = 1.0) and only weakly correlated with MI size by MPI (r = 0.130, p = 0.007). In conclusion, CK, CK-MB, and troponin I measured at 12 hours, at peak, and as the area under the curve correlated well with infarct size, but CK level at 12 hours was the best marker. CK continues to be a useful marker of MI size despite the introduction of newer, more specific markers, especially when infarct onset is known with certainty as in patients with HC undergoing ASA.

Serum levels of NT-proBNP as surrogate for cardiac amyloid burden: new evidence from gadolinium-enhanced cardiac magnetic resonance imaging in patients with amyloidosis

BACKGROUND

The prognostic value of NT-proBNP has been recognized in patients with amyloidosis complicated by cardiac involvement. We aimed to use contrast enhanced cardiac magnetic resonance imaging (CMR) to identify functional and structural alterations related to levels of NT-proBNP better to understand the mechanisms of its release in cardiac amyloidosis.

METHODS AND RESULTS

CMR was performed on a 1.5-T scanner in 34 patients with biopsy proven amyloid light chain (AL; n = 27) or hereditary transthyretin related (TTR; n = 7) amyloidosis. NT-proBNP was higher in patients with (n = 25) compared to patients without cardiac involvement (n = 9) (2931 (IQR: 972-8629; min-max: 25-27,277) pg/ml vs. 177 (IQR: 71-1431; min-max: 22-7935) pg/ml, p = 0.008). ROC analysis identified a NT-proBNP of <2426.5 pg/ml as optimal discriminator for event free survival (682 +/- 65 days). NT-proBNP did not correlate with LV- ejection fraction, end-diastolic and end-systolic volumes or stroke volume. There was a moderate correlation between NT-proBNP and LV-mass (R = 0.52, p = 0.003) and extent of late gadolinium enhancement (LGE; R = 0.41, p = 0.04).

CONCLUSIONS

This study confirms the prognostic value of NT-proBNP in patients with AL and TTR amyloidosis and provides the novel finding that NT-proBNP correlates with surrogates of myocardial amyloid burden such as LV-mass and LGE, supporting the concept of NT-proBNP as a biomarker reflecting the severity of cardiac amyloid infiltration.

Inflammatory activation and left ventricular mass in essential hypertension

BACKGROUND

Inflammation is an independent risk factor for high blood pressure, and as a consequence inflammatory cytokines could be related with left ventricular hypertrophy (LVH). We sought to assess the association and predictive role of different cytokine levels with LVH in a group of patients with essential hypertension (HT).

METHODS

We studied 251 asymptomatic hypertensive patients (142 with LVH and 109 without LVH), referred from 11 hospitals. A routine physical examination, laboratory analyses, and echo-Doppler study were performed. Plasma soluble tumor necrosis factor (TNF) receptors (sTNF-R1 and sTNF-R2), interleukin-6 (IL-6), and interleukin-1 receptor antagonist (IL-1ra) were centrally determined.

RESULTS

Hypertensive patients with LVH had higher inflammatory cytokine levels than the group without hypertrophy (P < 0.001). Multivariate linear regression reported that sTNF-R1 (P < 0.01) was an independent predictor of left ventricular mass index (LVMI). All cytokines had significant area under the curves for detection of LVH, but sTNF-R1 has the highest area, 0.71 +/- 0.03 (P < 0.001). Finally, prevalence of LVH was increased in the group of patients with higher cytokine levels, and logistic regression analysis showed that sTNF-R1 (odds ratio = 2.59, 95% CI of 1.14-5.87) was an independent predictor of LVH.

CONCLUSIONS

Cytokine levels were significantly correlated with LVMI in hypertensive patients. The sTNF-R1 was an independent predictor of LVMI. Plasma sTNF-R1 concentrations could be a predictive factor of LVH in patients with essential HT.

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

BACKGROUND

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

HYPOTHESIS

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

METHODS

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

RESULTS

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

CONCLUSION

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

Biomarkers of pathophysiology in hypertrophic cardiomyopathy: implications for clinical management and prognosis

The study of biomarkers and their signalling pathways has allowed the development of new therapeutic strategies in a range of disorders. The aim of the present systematic review is to provide an overview of different biomarkers in patients with hypertrophic cardiomyopathy that could give some insight into the pathophysiologic mechanism(s) underlying the typical clinical and histological manifestations of the disease. Several pathophysiological models are presented and discussed, including studies that have investigated these biomarkers for diagnostic and prognostic reasons, in relation to disease progression and/or mortality.

Plasma brain natriuretic peptide as a surrogate marker for cardioembolic stroke

Background

Cardioembolic stroke generally results in more severe disability, since it typically has a larger ischemic area than the other types of ischemic stroke. However, it is difficult to differentiate cardioembolic stroke from non-cardioembolic stroke (atherothrombotic stroke and lacunar stroke). In this study, we evaluated the levels of plasma brain natriuretic peptide in acute ischemic stroke patients with cardioembolic stroke or non-cardioembolic stroke, and assessed the prediction factors of plasma brain natriuretic peptide and whether we could differentiate between stroke subtypes on the basis of plasma brain natriuretic peptide concentrations in addition to patient's clinical variables.

Methods

Our patient cohort consisted of 131 consecutive patients with acute cerebral infarction who were admitted to Kagawa University School of Medicine Hospital from January 1, 2005 to December 31, 2007. The mean age of patients (43 females, 88 males) was 69.6 ± 10.1 years. Sixty-two patients had cardioembolic stroke; the remaining 69 patients had non-cardioembolic stroke (including atherothrombotic stroke, lacunar stroke, or the other). Clinical variables and the plasma brain natriuretic peptide were evaluated in all patients.

Results

Plasma brain natriuretic peptide was linearly associated with atrial fibrillation, heart failure, chronic renal failure, and left atrial diameter, independently (F_4,126 = 27.6, p < 0.0001; adjusted R² = 0.45). Furthermore, atrial fibrillation, mitral regurgitation, plasma brain natriuretic peptide (> 77 pg/ml), and left atrial diameter (> 36 mm) were statistically significant independent predictors of cardioembolic stroke in the multivariable setting (Χ² = 127.5, p < 0.001).

Conclusion

It was suggested that cardioembolic stroke was strongly predicted with atrial fibrillation and plasma brain natriuretic peptide. Plasma brain natriuretic peptide can be a surrogate marker for cardioembolic stroke.

Does B-type natriuretic peptide predict the new onset of hypertension?

Increased B-type natriuretic peptide (BNP) expression precedes the development of hypertension in spontaneously hypertensive rats. We therefore tested the hypothesis that elevated plasma BNP levels predict the onset of hypertension in normotensive subjects. Japanese normotensive participants who were at our hospital for a yearly physical check-up (mean age 52.7 years, 35.9% women, n=5,026) were enrolled in the study. Blood pressure and BNP were measured at baseline and subjects were followed up for 5 years (median 1,114 d), with the endpoint being the development of hypertension. We evaluated the relationship between plasma BNP levels at baseline and the incidence of hypertension during the follow-up period. Hypertension was defined as systolic or diastolic blood pressure > or =140 or > or =90 mmHg, respectively, or the use of antihypertensive medications. During the follow-up period, hypertension developed in 23.4% (77.0 per 1,000 person-years) and 14.9% (51.0 per 1,000 person-years) of male and female subjects, respectively. Cox proportional hazard regression analysis demonstrated that after adjustment for known risk factors, the risk of hypertension was increased from the first to fourth quartiles of baseline BNP levels. However, after additional adjustment for baseline blood pressure, BNP did not predict the new onset of hypertension. Baseline BNP levels are closely associated with the risk of hypertension in individuals with normal blood pressure, but the prediction of hypertension with BNP is largely dependent on baseline blood pressure. Measurements of BNP may serve as a complementary method for the prediction or confirmation of hypertension.

Significance of plasma levels of N-terminal Pro-B-type natriuretic peptide on left ventricular remodeling in non-obstructive hypertrophic cardiomyopathy attributable to the Asp175Asn mutation in the alpha-tropomyosin gene

Hypertrophic cardiomyopathy (HC) is an inherited heart disease characterized by left ventricular (LV) remodeling. The present study was conducted to investigate the association of N-terminal pro-B-type natriuretic peptide (NT-pro-BNP) levels with LV remodeling on magnetic resonance imaging and procollagen formation in 17 healthy controls and 24 patients with nonobstructive HC attributable to an identical Asp175Asn (aspartic acid to asparagine at codon 175) mutation in the alpha-tropomyosin gene. None of the patients had history of decompensated heart failure, and all patients had normal LV ejection fraction. Patients with HC had higher NT-pro-BNP levels compared with controls (median 60 pmol/L, range <40 to 359, vs <40 pmol/L; p <0.001), but 9 patients with HC had normal NT-pro-BNP levels (<40 pmol/L). In patients with HC, levels of NT-pro-BNP were correlated significantly with LV end-systolic volume index (r = 0.50, p <0.05), LV mass index (r = 0.47, p <0.05), proportion of hypokinetic segments (r = 0.50, p <0.05), and levels of serum aminoterminal propeptide of type III procollagen (r = 0.52, p <0.01). When patients with HC were divided into 3 groups on the basis of their NT-pro-BNP levels, there were statistically significant linear associations of LV end-systolic volume (test for linearity p = 0.034), LV mass index (p = 0.009), proportion of hypokinetic segments (p = 0.016), and levels of serum aminoterminal propeptide of type III procollagen (p = 0.020) with NT-pro-BNP levels over the 3 groups, suggesting a tight relation between LV remodeling and levels of NT-pro-BNP. In conclusion, in patients with nonobstructive HC attributable to an Asp175Asn mutation in the alpha-tropomyosin gene, elevated NT-pro-BNP levels are associated with incipient LV remodeling, suggesting that NT-pro-BNP could be used to diagnose insidious unfavorable LV remodeling in HC.

TG-interacting factor is required for the differentiation of preadipocytes

The accumulation of visceral adipose tissue is closely associated with insulin resistance and metabolic syndrome. Therefore, it is important to identify genes that are required for adipocyte differentiation. To identify genes that are required for the differentiation of 3T3-L1 preadipocytes into mature adipocytes, we used retrovirus insertion-mediated random mutagenesis to generate 3T3-L1 cell lines that lose their ability to differentiate into mature adipocytes. One of the genes identified was TG-interacting factor (TGIF), a DNA binding homeodomain protein that has been demonstrated to suppress Smad-mediated activation of transforming growth factor beta (TGF-beta)-regulated transcription. In the TGIF-disrupted clone of 3T3-L1 preadipocytes, the rate of differentiation into mature adipocytes was clearly reduced compared with that in the wild-type clone. Suppression of TGIF by lentivirus-mediated RNAi also inhibited the differentiation of 3T3-L1 cells. Insulin specifically increased the abundance of TGIF protein, primarily by enhancing its stability. In addition, insulin caused the rapid accumulation of TGIF in the nuclei. Forced expression of exogenous TGIF repressed both endogenous and overexpressed Smad2/3-mediated promoter activity in 3T3-L1. These findings suggest that insulin specifically antagonizes TGF-beta signaling in preadipocytes by stabilizing the putative Smad transcriptional corepressor TGIF and regulates adipocyte differentiation.

The effect of percutaneous balloon mitral valvuloplasty on N-terminal- pro B- type natriuretic peptide plasma levels in mitral stenosis

The objectives of this study were to assess the effect of percutaneous mitral balloon valvuloplasty (PBMV) on the plasma levels of N-terminal-pro B-type natriuretic peptide (NT-proBNP) in patients with mitral stenosis (MS) and to investigate the relationship between the changes in hemodynamic variables and NT-proBNP levels after PBMV. Plasma NT-proBNP concentrations were obtained from 60 symptomatic patients with rheumatic MS who underwent PBMV, and in 35 age- and gender-matched healthy volunteers. Patients with MS were found to have significantly higher levels of plasma NT-proBNP compared to the control group (293 [77-1093] pg/mL versus 24 [12-67] pg/mL, respectively; [P < 0.001]). The mean preprocedural NT-proBNP level fell significantly from 293 (77-1093) pg/mL to 214 (69-1028) pg/mL (P < 0.001) following PBMV. The percentage decrease in plasma NT- proBNP levels was correlated only with the percentage decrease in systolic pulmonary artery pressure (r = 0.687, P < 0.001) and this correlation persisted in linear regression analysis (beta = -0.013; 95% CI [-0.018- -0.008] and P < 0.001). However, NT-proBNP levels did not correlate with the percentage of improvement in NYHA functional class, mitral valve gradients, or left atrial pressure (all P > 0.05). These findings indicate that NT-proBNP measurement following PBMV may be valuable for evaluating changes in pulmonary artery pressure and that elevated NT- proBNP levels in patients with MS may reflect the increased wall stress in the left atrium and right side of the heart.

Clinical significance of N-terminal-probrain natriuretic peptide in hypertrophic cardiomyopathy

N-Terminal-probrain natriuretic peptide (NT-proBNP) plasma levels are elevated in patients with congestive heart failure. Published data concerning the utility of NT-proBNP in hypertrophic cardiomyopathy (HCM) are lacking. Our aim was to evaluate the clinical significance of NT-proBNP in patients with HCM. A blood sample was collected for plasma NT-proBNP measurement from 43 consecutive patients with documented HCM. NT-proBNP was measured using a chemiluminescent immunoassay kit (Roche Diagnostics) on an Elecsys 2010 analyzer. Median value of NT-proBNP was 219 pg/ml (range 8-3 045 pg/ml) in NYHA class I patients, 698 pg/ml (125-2 463 pg/ml) in NYHA class II patients, and 2 683 pg/ml (131-11 542 pg/ml) in NYHA class III and IV patients. NT-proBNP plasma levels were significantly higher across the severity of functional limitation (i.e., NYHA class classification) (P = 0.002). NT-proBNP levels were significantly higher in female than male (P = 0.034), in referral vs nonreferral patients (P = 0.004), in symptomatic vs asymptomatic patients (P = 0.020), in patients with basal subaortic gradient >or=30 mmHg (P = 0.001) and in the patients who were on cardioactive medication (P = 0.010). In univariate analysis NT-proBNP was significantly correlated with age (P < 0.001), left ventricular maximum wall thickness (P = 0.001), left atrial size (P = 0.019), and subaortic gradient >or=30 mmHg (P < 0.001). In multivariate regression analysis, age (P < 0.001), maximum wall thickness (P = 0.007), and gradient >or=30 mmHg (P = 0.027) were independently associated with NT-proBNP levels. Our data support the idea that measurement of plasma NT-proBNP levels in HCM patients is useful to assess their clinical status, especially the severity of hypertrophy and the presence of obstruction, although age must be taken into account.

Usefulness of brain natriuretic peptide levels in the clinical evaluation of patients with hypertrophic cardiomyopathy

Hypertrophic cardiomyopathy (HC) is associated frequently with heart failure symptoms and diastolic dysfunction. Although the influence of brain natriuretic peptide (BNP) levels in the management of patients with systolic dysfunction is evolving, there are few data on the role of BNP in the management of patients with HC. BNP was compared with clinical and echocardiographic variables, including measures of diastolic filling, in 217 patients with HC. BNP values were correlated with New York Heart Association classification, echocardiographic estimates of diastolic filling pressure, and right ventricular systolic pressure even after adjusting for age, gender, renal function, and body habitus. However, the overlap of the BNP levels in these respective categories was notable. BNP values did not correlate with objective measures of exercise capacity, and serial BNP values did not track changes in clinical status. In conclusion, BNP levels in patients with HC are associated with similar subjective and objective measures as have been observed in patients with left ventricular systolic dysfunction, but these correlations are relatively weak and do not allow the precise characterization of clinical status.

N-Terminal Pro Brain Natriuretic Peptide to Predict Prognosis in Dilated Cardiomyopathy with Sinus Rhythm

AIMS

To assess the value of plasma NT proBNP levels for predicting adverse outcomes in patients with dilated cardiomyopathy (DCM).

METHODS

Seventy-eight patients with DCM (EF <40%) with sinus rhythm were enrolled. All patients had undergone echocardiographic examination, coronary angiography, and cardiac catheterisation. Blood samples for plasma NT proBNP levels were taken at rest following echocardiographic examination. Patients were followed up for 660+/-270 days for clinical endpoints defined as; death from worsening heart failure, sudden cardiac death and heart transplantation (Tx).

RESULTS

Clinical end points were observed in 19 patients (5 Tx, 4 sudden cardiac death, 10 death from worsening heart failure). Variables associated with an increased hazard of clinical endpoints in univariate analysis were log NT proBNP, age, NYHA functional class, left ventricle ejection fraction, mitral valve effective regurgitation orifice area, and E wave deceleration time. The plasma level of NT proBNP (Hazard ratio=2.5 [95% CI: 1.3-4.7], p=0.0024) and age (hazard ratio=0.94 [95% CI: 0.90-0.98], p=0.0005) were the independent variables associated with an increased risk of clinical endpoints. NT proBNP plasma level >4500 pg/ml detected patients with clinical endpoints with a sensitivity, and specificity of 72%, 80%, respectively. The event free survival was found to be significantly lower in patients with NT proBNP levels >4500 pg/ml.

CONCLUSION

NT proBNP seems to be a strong predictor of adverse outcomes in patients with DCM with sinus rhythm and may be used as a reliable biological marker in risk stratification.

Increased Brain Natriuretic Peptide Secretion is a Marker of Disease Progression in Nonobstructive Hypertrophic Cardiomyopathy

BACKGROUND

Hypertrophic cardiomyopathy (HCM) is associated with increased plasma brain natriuretic peptide (BNP), but sequential plasma and myocardial BNP assessment in stable and dilated HCM has never been performed.

METHODS AND RESULTS

Forty consecutive HCM patients (42 +/- 8 years, 25 males) underwent cardiac catheterization, angiography, and left ventricular (LV) endomyocardial biopsy. During follow-up (70.5 +/- 6.7 months), 30 patients (Group 1) remained stable whereas 10 patients (Group 2) progressed to dilated phase. Group 2 patients underwent a second invasive study with LV biopsy. BNP plasma levels were measured at baseline and at follow-up in all patients. All biopsies were processed for histology and immunohistochemistry with anti-BNP antibodies. BNP plasma levels remained unchanged in Group 1, whereas it significantly increased in all Group 2 patients who exhibited an elevation of LV and right ventricular end-diastolic pressure. Immunohistochemistry showed an increase of BNP-positive myocytes in follow-up biopsies when compared with baseline (75.0 +/- 15.0 % versus 29.8 +/- 10.0 %; P = .005) with a significant correlation with LV end-diastolic pressure (r = 0.78, P < .001) and plasma BNP (r = 0.83, P < .001).

CONCLUSIONS

Progression to end-stage of HCM is characterized by further increase of myocardial and plasma BNP. Serial assessment of plasma BNP may provide noninvasive recognition of hemodynamic deterioration, allowing prompt institution of heart failure therapy.

Mutation analysis of the natriuretic peptide precursor B (NPPB) gene in patients with hypertrophic cardiomyopathy

BACKGROUND

Hypertrophic cardiomyopathy (HCM) is a genetically heterogenous disease caused by mutations in genes that primarily encode sarcomeric proteins. No mutation is identified in up to 40% of HCM patients, suggesting other causative genes exist. Natriuretic peptide precursor B (NPPB; also known as "BNP") is a cardiac hormone involved in body fluid homeostasis and cardiac myocyte growth. NPPB concentrations are markedly increased in patients with ventricular hypertrophy, and it is therefore possible mutations in the NPPB gene could cause HCM.

METHODS

Genomic DNA was extracted from peripheral blood in 238 consecutive probands with HCM. The coding regions and intron/exon boundaries in the NPPB gene were amplified by PCR, and products were screened for sequence variants using high-performance liquid chromatography, followed by direct DNA sequencing.

RESULTS

Four sequence variants in the NPPB gene were identified in 9 of the 238 probands screened. Two of the variants were intronic, one was a synonymous variant at codon 79, and the final variant resulted in an amino acid substitution from arginine to histidine at codon 47 (Arg47His). The Arg47His variant was identified in a control population consisting of 204 chromosomes at an allelic frequency of 0.5%, and is therefore unlikely to cause disease.

CONCLUSION

No disease causing mutations were identified in the NPPB gene in this cohort, indicating that mutations in this gene are unlikely to be responsible for HCM.