Prognostic importance of atrial natriuretic peptide in patients with chronic heart failure

Development of a high-throughput liquid chromatography-tandem mass spectrometry platform for the determination of intact natriuretic peptides in human plasma

We present an innovative, reliable, and antibody-free analytical method to determine multiple intact natriuretic peptides in human plasma. These biomolecules are routinely used to confirm the diagnosis and monitor the evolution of heart failure, so that their determination is essential to improve diagnosis and monitor the efficacy of treatment. However, common immunoassay kits suffer from main limitations due to high cross-reactivity with structurally similar species. In our method, we pre-treated the sample by combining salting-out with ammonium sulfate with microextraction by packed sorbent technique. Analyses were then carried out by ultra-high performance liquid chromatography-electrospray ionization-tandem mass spectrometry. The use of 3-nitrobenzyl alcohol as a supercharger reagent enhanced the ESI ionization and improved the signal-to-noise ratio. The analytical protocol showed good linearity over one order of magnitude, recovery in the range of 94-105 %, and good intra- and inter-day reproducibility (RSD<20 %), and the presence of a matrix effect. Limits of detection were in the range of pg/mL for all peptides (0.2-20 pg/mL). Stability study in plasma samples demonstrated that proper protease inhibitors need to be included in blood collection tubes to avoid peptide degradation. Preliminary analyses on plasma samples from heart failure patients allow the quantification of ANP 1-28 as the most abundant species and the detection of ANP 5-28, BNP 1-32, and BNP 5-32. The method could be used to investigate how cross-reactivity issues among structurally similar species impact determinations by ELISA kits.

The First Dedicated Comprehensive Heart Failure Program in the United States: The Division of Circulatory Physiology at Columbia Presbyterian (1992-2004)

The first dedicated multidisciplinary heart failure program in the United States was founded as the Division of Circulatory Physiology at the Columbia University College of Physicians & Surgeons in 1992. The Division was administratively and financially independent of the Division of Cardiology and grew to 24 faculty members at its peak. Its administrative innovations included (1) a comprehensive full-integrated service line, with 2 differentiated clinical teams, one devoted to drug therapy and the other to heart transplantation and ventricular assist devices; (2) a nurse specialist/physician assistant-led clinical service; and (3) a financial structure independent of (and not supported by) other cardiovascular medical or surgical services. The division had 3 overarching missions: (1) to promote a unique career development path for each faculty member to be linked to recognition in a specific area of heart failure expertise; (2) to change the trajectory and enhance the richness of intellectual discourse in the discipline of heart failure, so as to foster an understanding of fundamental mechanisms and to develop new therapeutics; and (3) to provide optimal medical care to patients and to promote the ability of other physicians to provide optimal care. The major research achievements of the division included (1) the development of beta-blockers for heart failure, from initial hemodynamic assessments to proof-of-concept studies to large-scale international trials; (2) the development and definitive assessment of flosequinan, amlodipine, and endothelin antagonists; (3) initial clinical trials and concerns with nesiritide; (4) large-scale trials evaluating dosing of angiotensin converting-enzyme inhibitors and the efficacy and safety of neprilysin inhibition; (5) identification of key mechanisms in heart failure, including neurohormonal activation, microcirculatory endothelial dysfunction, deficiencies in peripheral vasodilator pathways, noncardiac factors in driving dyspnea, and the first identification of subphenotypes of heart failure and a preserved ejection fraction; (6) the development of a volumetric approach to the assessment of myocardial shortening; (7) conceptualization and early studies of cardiac contractility modulation as a treatment for heart failure; (8) novel approaches to the identification of cardiac allograft rejection and new therapeutics to prevent allograft vasculopathy; and (9) demonstration of the effect of left ventricular assist devices to induce reverse remodeling, and the first randomized trial showing a survival benefit with ventricular assist devices. Above all, the division served as an exceptional incubator for a generation of leaders in the field of heart failure.

Prognostic Value of Novel Natriuretic Peptide Index After Percutaneous Coronary Intervention

BACKGROUND

The predictive value of both atrial natriuretic peptide (ANP) and B-type natriuretic peptide (BNP) is well known. This study evaluated the prognostic value of a novel natriuretic peptide index (NPI) combining ANP and BNP.

METHODS AND RESULTS

This study included 849 consecutive patients with coronary artery disease who underwent successful percutaneous coronary intervention (PCI). Patients were followed up clinically for up to 3 years or until the occurrence of major adverse cardiac events (MACE). The primary endpoint was a composite of all-cause death and non-fatal myocardial infarction. The NPI (pg/mL) was defined as √ANP×BNP. MACE occurred in 73 patients (8.6%) during the follow-up period. Receiver operating characteristic curve analysis showed the highest area under the curve for NPI (0.779) compared with ANP and BNP (0.773 and 0.755, respectively). A risk analysis of MACE occurrence adjusted for the multivariable model showed the highest hazard ratio (HR) for NPI (1.33; 95% confidence interval [CI] 1.18-1.51; P<0.001) compared with ANP and BNP (HR 1.25 [95% CI 1.13-1.39] and 1.30 [95% CI 1.13-1.49], respectively; P<0.001). The NPI was a significant independent predictor of MACE, among other clinical parameters, in the multivariable analysis.

CONCLUSIONS

Compared with ANP and BNP, the NPI was more effective in predicting future adverse events after PCI.

Stx4 is required to regulate cardiomyocyte Ca2+ handling during vertebrate cardiac development

Requirements for vesicle fusion within the heart remain poorly understood, despite the multitude of processes that necessitate proper intracellular trafficking within cardiomyocytes. Here, we show that Syntaxin 4 (STX4), a target-Soluble N-ethylmaleimide sensitive factor attachment receptor (t-SNARE) protein, is required for normal vertebrate cardiac conduction and vesicular transport. Two patients were identified with damaging variants in STX4. A patient with a homozygous R240W missense variant displayed biventricular dilated cardiomyopathy, ectopy, and runs of non-sustained ventricular tachycardia, sensorineural hearing loss, global developmental delay, and hypotonia, while a second patient displayed severe pleiotropic abnormalities and perinatal lethality. CRISPR/Cas9-generated stx4 mutant zebrafish exhibited defects reminiscent of these patients' clinical presentations, including linearized hearts, bradycardia, otic vesicle dysgenesis, neuronal atrophy, and touch insensitivity by 3 days post fertilization. Imaging of Vamp2+ vesicles within stx4 mutant zebrafish hearts showed reduced docking to the cardiomyocyte sarcolemma. Optical mapping of the embryonic hearts coupled with pharmacological modulation of Ca²⁺ handling together support that zebrafish stx4 mutants have a reduction in L-type Ca²⁺ channel modulation. Transgenic overexpression of zebrafish Stx4^R241W, analogous to the first patient's STX4^R240W variant, indicated that the variant is hypomorphic. Thus, these data show an in vivo requirement for SNAREs in regulating normal embryonic cardiac function and that variants in STX4 are associated with pleiotropic human disease, including cardiomyopathy.

Intensive Lifestyle Intervention Increases Plasma Midregional Proatrial Natriuretic Peptide Concentrations in Overweight Children

Background

Overweight adults have low circulating concentrations of ANP (atrial natriuretic peptide) and proANP fragments. We tested the hypothesis that an intensive lifestyle intervention with an intended weight loss would increase plasma concentrations of a proANP fragment in overweight children.

Methods and Results

We measured MR‐proANP (midregional proANP) concentrations in plasma from overweight children who participated in the OOIS (Odense Overweight Intervention Study). OOIS randomized 115 overweight children (11–13 years, 55% girls) to an intensive day‐camp intervention arm with increased physical activity and healthy diet or to a less intensive standard intervention arm for 6 weeks. We used linear mixed‐effects modeling for repeated measures to estimate the difference in the mean change with 95% CIs in fasting plasma MR‐proANP concentrations between the 2 arms, and we used partial least squares regression analysis to identify candidate mediators. Differences in weight, fitness, and metabolic factors were also analyzed. At baseline, fasting plasma MR‐proANP concentrations were (median [interquartile range]) 35.0 pmol/L (26.8–42.0) in the day‐camp intervention arm and 37.2 pmol/L (31.7–44.7) in standard intervention arm participants, respectively. After 6 weeks intervention, children in the day‐camp intervention arm had increased their MR‐proANP (5.4 pmol/L [0.8–10.0], P=0.022) and their fitness (2.33 mL O₂/min per kg [0.52–4.14], P=0.012) and they had deceased their body mass index (−2.12 kg/m² [−2.59 to −1.65], P<0.001) as compared with children in standard intervention arm. In the partial least squares analysis, decreases in fasting insulin and in estimated insulin resistance were associated with the observed increase in MR‐proANP concentrations.

Conclusions

An intensive lifestyle intervention increases plasma MR‐proANP among overweight children.

Registration

URL: https://www.clinicaltrials.gov; Unique identifier: NCT01574352.

Higher galectin-3 levels are independently associated with lower anxiety in patients with risk factors for heart failure

Background

Galectin-3 promotes the proliferation of neural progenitor cells and is engaged in cell-cell adhesion, cell-matrix interactions, and macrophage activation. In addition, in patients with heart failure this carbohydrate-binding protein is a known prognostic marker for cardiovascular mortality. However, its association with psychological variables has not been investigated so far.

Methods

Using data from the multicenter, observational Diast-CHF (Diagnostic Trial on Prevalence and Clinical Course of Diastolic Dysfunction and Heart Failure) trial, we studied in participants with cardiovascular risk factors (n = 1260, age 66.7 ± 8.0 years, males 51%, left ventricular ejection fraction 60.0 ± 8.1%) the relationship between serum concentrations of galectin-3 and anxiety. Galectin-3 levels were measured by means of a sandwich enzyme-linked immunosorbent assay, and anxiety was assessed using the Hospital Anxiety and Depression Scale (HADS).

Results

In univariate analysis, there was a weak but significant inverse correlation between galectin-3 and HADS anxiety (rho = − 0.076; p = 0.008). Linear regression models adjusted for sex, age, body-mass index, estimated glomerular filtration rate, left ventricular ejection fraction, 6-min walking distance, the 36-item Short-Form Health Survey (SF-36) subscale physical functioning, and known biomarkers for heart failure confirmed that serum galectin-3 significantly and independently predicted self-rated anxiety (B = -2.413; 95%CI = -2.413–-4.422; p = 0.019).

Conclusion

In patients with cardiovascular risk factors, serum concentrations of galectin-3 showed an inverse association with anxiety, which was independent of both the severity of physical impairment and established risk factors for the progression of heart failure.

Plasma proatrial natriuretic peptide associates with lipid oxidation during exercise and cardiorespiratory fitness in healthy young adults

Atrial natriuretic peptide (ANP) is known for its natriuretic, diuretic, and vasodilatory properties. However, ANP also has metabolic effects stimulating lipolysis and lipid oxidation. Overweight individuals have decreased circulating ANP concentrations. It has been proposed that this potential ANP deficiency could have biological consequences in overweight-related disorders, including decreased lipolysis and lipid oxidation. The purpose of this study was to investigate the relationships between ANP, exercise-induced lipid oxidation, and cardiorespiratory fitness in 562 20-28-year-old healthy community-based women and men. We measured fasting plasma concentrations of mid-regional proANP (MR-proANP), a stable marker of ANP secretion, the respiratory exchange ratio (RER) during sub-maximal exercise, which provides an estimate of lipid oxidation, and maximal oxygen consumption (VO₂-max) at the end of a maximal exercise test, which is a measure of cardiorespiratory fitness. An increase of 10 pmol/L in fasting plasma MR-proANP concentrations was related to an increase in relative VO₂-max of 0.78 (95% CI 0.36-1.09) ml O₂/min/kg and a decrease in RER of -0.0094 (-0.014 to -0.0045) in age- and sex-adjusted analysis (P < 0.001). Further adjusted for body mass index, a rise of 10 pmol/L in fasting plasma MR-proANP concentrations was associated with a rise in relative VO₂-max of 0.60 (0.28-0.92) ml O₂/min/kg and a fall in RER of -0.0096 (-0.015 to -0.0048) (P < 0.001). Fasting plasma MR-proANP concentrations associate with lipid oxidation during exercise and cardiorespiratory fitness in healthy young adults. The data support the existence of important connections between the endocrine heart, hemodynamics, and metabolism.

Racial differences in the association of NT-proBNP with risk of incident heart failure in REGARDS

BACKGROUND

Black individuals have lower natriuretic peptide levels and greater risk of heart failure (HF) than white individuals. Higher N-terminal-pro-B-type natriuretic peptide (NT-proBNP) is associated with increased risk of incident HF, but little information is available in black individuals. We examined race-specific differences in 1) the association of NT-proBNP with incident HF and 2) the predictive ability of NT-proBNP for incident HF across body mass index (BMI) and estimated glomerular filtration rate (eGFR) categories.

METHODS

In a prospective case-cohort study, baseline NT-proBNP was measured among 687 participants with incident HF and 2,923 (weighted 20,075) non-case randomly selected participants. Multivariable Cox proportional hazard modeling was used to assess the objectives of our study. Global Wald Chi-square score estimated from multivariable Cox models was used to assess predictive ability of NT-proBNP across BMI and eGFR categories.

RESULTS

In the multivariable model, a doubling of NT-proBNP concentration was associated with greater risk of incident HF among white individuals [hazard ratio (HR): 1.73; 95% CI: 1.55-1.94] than black individuals (HR: 1.51; 95% CI: 1.34-1.70); Pinteraction by race = 0.024. Higher NT-proBNP was the strongest predictor of incident HF across all BMI and eGFR categories among white individuals. By contrast, among black individuals with obesity (BMI ≥ 30 kg/m2) or eGFR < 60 mL/min/1.73 m2, the predictive ability of NT-proBNP for incident HF was attenuated.

CONCLUSIONS

The magnitude of the association of higher NT-proBNP with incident HF risk was greater among white individuals than black individuals. The diminished ability of NT-proBNP to predict the risk of HF in black population with obesity or impaired kidney function highlights the need of further investigations.

Natriuretic peptides in heart failure: Current achievements and future perspectives

The last two centuries have witnessed countless discoveries in the field of medicine that found their roots in the up growing development of technology as well as in the visionary ideas of brilliant scientists and research groups. One of the most important discoveries in the field of cardiovascular medicine allowed to break the paradigm identifying the heart with mere mechanical pump and to characterize its intriguing endocrine properties. Indeed, the discovery of hormones produced by the cardiac chambers, the natriuretic peptides, represents one of the milestones of the current conception of complexity of integrated human physiology. In the last four decades, the role of these hormones in the regulation of the cardiovascular system, in physiology and diseases, has been defined piece after piece. From diagnostic and prognostic markers, natriuretic peptides have become one of the most relevant clinical biomarker and a reliable target for establishing the efficacy of therapies. Recently and successfully, natriuretic peptide-based strategies are proposed as therapeutic weapons to improve outcome in heart failure. The future will witness potential further therapeutic application of natriuretic peptides that are currently being actively investigated.

Prognostic performance of serial in-hospital measurements of copeptin and multiple novel biomarkers among patients with worsening heart failure: results from the MOLITOR study

Aims

In heart failure, various biomarkers are established for diagnosis and risk stratification; however, little is known about the relevance of serial measurements during an episode worsening heart failure (WHF). This study sought to investigate the trajectory of natriuretic peptides and multiple novel biomarkers during hospitalization for WHF and to determine the best time point to predict outcome.

Methods and results

MOLITOR (Impact of Therapy Optimisation on the Level of Biomarkers in Patients with Acute and Decompensated Chronic Heart Failure) was an eight‐centre prospective study of 164 patients hospitalized with a primary diagnosis of WHF. C‐terminal fragment of pre‐pro‐vasopressin (copeptin), N‐terminal pro‐B‐type natriuretic peptide (NT‐proBNP), mid‐regional pro‐atrial natriuretic peptide (MR‐proANP), mid‐regional pro‐adrenomedullin (MR‐proADM), and C‐terminal pro‐endothelin‐1 (CT‐proET1) were measured on admission, after 24, 48, and 72 h, and every 72 h thereafter, at discharge and follow‐up visits. Their performance to predict all‐cause mortality and rehospitalization at 90 days was compared. All biomarkers decreased during recompensation (P < 0.05) except MR‐proADM. Copeptin at admission was the best predictor of 90 day mortality or rehospitalization (χ² = 16.63, C‐index = 0.724, P < 0.001), followed by NT‐proBNP (χ² = 10.53, C‐index = 0.646, P = 0.001), MR‐proADM (χ² = 9.29, C‐index = 0.686, P = 0.002), MR‐proANP (χ² = 8.75, C‐index = 0.631, P = 0.003), and CT‐proET1 (χ² = 6.60, C‐index = 0.64, P = 0.010). Re‐measurement of copeptin at 72 h and of NT‐proBNP at 48 h increased prognostic value (χ² = 23.48, C‐index = 0.718, P = 0.00001; χ² = 14.23, C‐index = 0.650, P = 0.00081, respectively).

Conclusions

This largest sample of serial measurements of multiple biomarkers in WHF found copeptin at admission with re‐measurement at 72 h to be the best predictor of 90 day mortality and rehospitalization.

Impact of Exhaled Breath Acetone in the Prognosis of Patients with Heart Failure with Reduced Ejection Fraction (HFrEF). One Year of Clinical Follow-up

BACKGROUND

The identification of new biomarkers of heart failure (HF) could help in its treatment. Previously, our group studied 89 patients with HF and showed that exhaled breath acetone (EBA) is a new noninvasive biomarker of HF diagnosis. However, there is no data about the relevance of EBA as a biomarker of prognosis.

OBJECTIVES

To evaluate whether EBA could give prognostic information in patients with heart failure with reduced ejection fraction (HFrEF).

METHODS

After breath collection and analysis by gas chromatography-mass spectrometry and by spectrophotometry, the 89 patients referred before were followed by one year. Study physicians, blind to the results of cardiac biomarker testing, ascertained vital status of each study participant at 12 months.

RESULTS

The composite endpoint death and heart transplantation (HT) were observed in 35 patients (39.3%): 29 patients (32.6%) died and 6 (6.7%) were submitted to HT within 12 months after study enrollment. High levels of EBA (≥3.7μg/L, 50th percentile) were associated with a progressively worse prognosis in 12-month follow-up (log-rank = 11.06, p = 0.001). Concentrations of EBA above 3.7μg/L increased the risk of death or HT in 3.26 times (HR = 3.26, 95%CI = 1.56-6.80, p = 0.002) within 12 months. In a multivariable cox regression model, the independent predictors of all-cause mortality were systolic blood pressure, respiratory rate and EBA levels.

CONCLUSIONS

High EBA levels could be associated to poor prognosis in HFrEF patients.

Serum proatrial natriuretic peptide does not increase with higher systolic blood pressure in obese men

OBJECTIVE

Obese persons have low circulating natriuretic peptide (NP) concentrations. It has been proposed that this 'natriuretic handicap' could play a role in obesity-related hypertension. The normal physiological response of the NP system to an increase in blood pressure (BP) is an increase in NP secretion with concomitant higher circulating NP concentrations. In this study, we investigated whether higher BP would also be related to higher circulating NP concentrations in obese men; furthermore, we verified that BP had affected the hearts of our study participants, by determining left ventricular mass (LVM).

METHODS

We examined 103 obese healthy medication-free men. We measured 24-hour ambulatory BP (ABP). LVM was calculated using the Cornell voltage-duration product method. Fasting serum concentrations of midregional proatrial NP (MR-proANP), a surrogate for active ANP, were measured. Linear regression analysis was used to calculate age-adjusted standardised regression coefficients (β).

RESULTS

LVM and BP increased across systolic ABP quartiles (mean LVM±SD: 1599.1±387.2 mm ms in first vs 2188.5±551.3 mm ms in fourth quartile, p<0.001; mean systolic ABP±SD: 114.5±4.2 mm Hg in first vs 149.0±7.7 mm Hg in fourth quartile, p<0.001). Systolic ABP was robustly associated with LVM (ß=0.48, p<0.001). Despite evidence of BP-related increases in LVM, serum MR-proANP was negatively associated with systolic ABP (ß=-0.32, p=0.004) and with diastolic ABP (ß=-0.45, p<0.001).

CONCLUSIONS

Contrary to known physiological BP responses, MR-proANP was negatively associated with ABP in our study. This suggests that a low amount of circulating NPs could play a role in the early stage of obesity-related hypertension.

BNP and ANP as diagnostic and predictive markers in heart failure with left ventricular systolic dysfunction

Background

The prevalence of chronic heart failure (CHF) with systolic dysfunction is increasing. Plasma natriuretic peptides have been envisaged as diagnostic and predictive markers.

Aims

To investigate the relationship between the levels of B-type natriuretic peptide (BNP) and A-type natriuretic peptide (ANP) and the clinical and functional parameters of CHF in outpatients with CHF at baseline, compared with normal healthy controls; to find out the differences in a randomised controlled trial between patients treated with an angiotensin-converting enzyme (ACE) inhibitor, captopril, or an angiotensin receptor blocker (ARB), irbesartan. These differences were assessed throughout the six-month treatment period and at the sixth month.

Methods Plasma BNP (pmol/L) and ANP (pmol/L) were

determined in 68 hypertensive patients with dilated cardiomyopathy, NYHA class III-IV and ejection fraction (EF) <40%, and in 26 normal controls. Statistical analysis for BNP and ANP was done by Student's t-test. The patient group was randomly subdivided into two subgroups of 34 patients, each treated with either an ARB, irbesartan, or an ACE inhibitor (ACE-I), captopril. BNP and ANP were measured in both subsamples and correlated with clinical, functional and neurohormonal parameters throughout a follow-up period of six months and at the sixth month.

Results

The mean EF in the patient sample was 33.43±6.52% and in the controls was 61.96 ±3.53% (p=0.000). The mean BNP (pmol/L) in patients was 44.78±54.36 and in the controls was 7.12±8.28 (p=0.000) and the mean ANP (pmol/L) was 30.32±25.97 in patients and 11.18±7.92 in controls (p=0.000). A statistically significant difference was found between patients and healthy controls. Significant correlations were found between natriuretic peptides and EF. Between the baseline phase and the sixth month, BNP and ANP decreased significantly in the ARB group. At the sixth month, both BNP and ANP were lower in the ARB group. Evidence of clinical benefit was found with both ARB or ACE-I treatment throughout the six months, with patients moving from classes III and IV to class II NYHA. Improvement of EF was also found, with transition of patients with lower EF (even <30%) to higher values. EF was higher in the ARB group at the sixth month.

Conclusions

BNP and ANP can be useful diagnostic tools in hypertensive CHF patients with moderate-to-severe LV dysfunction. The decrease in BNP and ANP in the ARB group throughout six months, as well as the lower value at the sixth month, suggest a prognostic value of these parameters.

Depressed Corin Levels Indicate Early Systolic Dysfunction Before Increases of Atrial Natriuretic Peptide/B-Type Natriuretic Peptide and Heart Failure Development

Dilated cardiomyopathy is a major cause of heart failure (HF) that affects millions. Corin cleaves and biologically activates pro-atrial natriuretic peptide (pro-ANP) and pro-B-type natriuretic peptide (pro-BNP). High corin levels reduce the development of systolic dysfunction and HF in experimental dilated cardiomyopathy. Yet, patients with significant HF unexpectedly show low corin levels with high plasma ANP/BNP levels. Therefore, we examined the relationship between cardiac corin expression, ANP/BNP levels, and the stages of HF. We used a well-established, dilated cardiomyopathy model to evaluate gene and protein expression as mice longitudinally developed Stages A-D HF. Cardiac systolic function (ejection fraction) continuously declined over time (P<0.001). Cardiac corin transcripts were decreased at early Stage B HF and remained low through Stages C and D (P<0.001). Cardiac corin levels were positively correlated with systolic function (r=0.96, P=0.003) and inversely with lung water (r=-0.92, P=0.001). In contrast, cardiac pro-ANP/BNP transcripts increased later (Stages C and D) and plasma levels rose only with terminal HF (Stage D, P<0.001). Immunoreactive plasma ANP and BNP levels were positively associated with plasma cyclic guanosine monophosphate levels (r=0.82, P=0.01 and r=0.8, P=0.02, respectively). In experimental dilated cardiomyopathy, corin levels declined early with progressive systolic dysfunction before the development of HF, whereas significant increases in plasma ANP, BNP, and cyclic guanosine monophosphate levels were found only in later stage (C and D) HF. This dyssynchrony in expression of corin versus ANP/BNP may impair cleavage activation of pro-natriuretic peptides, and thereby promote the transition from earlier to later stage HF.

Natriuretic Peptides and Cardiometabolic Health

Natriuretic peptides are cardiac-derived hormones with a range of protective functions, including natriuresis, diuresis, vasodilation, lusitropy, lipolysis, weight loss, and improved insulin sensitivity. Their actions are mediated through membrane-bound guanylyl cyclases that lead to production of the intracellular second-messenger cyclic guanosine monophosphate. A growing body of evidence demonstrates that genetic and acquired deficiencies of the natriuretic peptide system can promote hypertension, cardiac hypertrophy, obesity, diabetes mellitus, the metabolic syndrome, and heart failure. Clinically, natriuretic peptides are robust diagnostic and prognostic markers, and augmenting natriuretic peptides is a target for therapeutic strategies in cardiometabolic disease. This review will summarize current understanding and highlight novel aspects of natriuretic peptide biology.

Racial Differences in Natriuretic Peptide Levels: The Dallas Heart Study

OBJECTIVES

The purpose of this study was to assess whether N-terminal pro-B-type natriuretic peptide (NT-proBNP) levels differ according to race/ethnicity.

BACKGROUND

Natriuretic peptides (NP) are hormones with natriuretic, diuretic, and vasodilatory effects. Experimental NP deficiency promotes salt-sensitive hypertension and cardiac hypertrophy, conditions that are more common among black individuals.

METHODS

We examined plasma NT-proBNP levels according to race/ethnicity in 3,148 individuals (51% black, 31% white, 18% Hispanic) free of prevalent cardiovascular disease in the Dallas Heart Study. NT-proBNP values in the bottom sex-specific quartile were defined as low. Multivariable linear and logistic regression analyses were performed adjusting for clinical covariates and magnetic resonance imaging measurements of cardiac structure and function.

RESULTS

Hypertension was present in 41%, 25%, and 16% of black, white, and Hispanic individuals, respectively. Unadjusted NT-proBNP levels were lowest in black (median: 24 pg/ml; interquartile range [IQR]: 10 to 52 pg/ml) as compared with Hispanic (30 pg/ml; IQR: 14 to 59 pg/ml) and white individuals (32 pg/ml; IQR: 16 to 62 pg/ml), p < 0.0001. In multivariable-adjusted models, black individuals still had significantly lower NT-proBNP levels (-39% [95% confidence interval: -46% to -31%]; p < 0.0001) and greater odds of having low NT-proBNP (odds ratio: 2.46 [95% confidence interval: 1.86 to 3.26]), compared with white individuals. In contrast, NT-proBNP levels did not significantly differ between Hispanic and white individuals (p = 0.28). The finding of lower NT-proBNP levels in black individuals was similar when analyses were restricted to healthy participants without cardiovascular risk factors.

CONCLUSIONS

In this multiethnic cohort, NT-proBNP levels differ substantially according to race/ethnicity. Despite a higher prevalence of hypertension, black individuals had significantly lower NP levels than white and Hispanic individuals. A relative NP "deficiency" among black individuals may lead to greater susceptibility to salt retention and hypertension.

Biomarkers in mechanical circulatory support

Heart failure is a complex multifaceted syndrome occurring as a result of impaired cardiac function. Understanding the neurohormonal, inflammatory and molecular pathways involved in the pathophysiology of this syndrome has led to the development of effective and widely used pharmacological treatments. Despite this, mortality and hospitalization rates associated with this condition remain high. The natural course of this illness is usually progressive, often leading inexorably to end stage heart failure, for which orthotopic heart transplant is a treatment option but one with limited resource. In the past decade, mechanical circulatory support has emerged as a potential therapy for certain patients with advanced heart failure. This article reviews the published data regarding biomarkers in the setting of mechanical circulatory support, and highlights areas of ongoing work and potential future areas of interest.

Cirrhotic cardiomyopathy: pathogenesis and clinical relevance

Cirrhosis is known to cause alterations in the systemic haemodynamic system. Cirrhotic cardiomyopathy designates a cardiac dysfunction that includes impaired cardiac contractility with systolic and diastolic dysfunction, as well as electromechanical abnormalities in the absence of other known causes of cardiac disease. This condition is primarily revealed by inducing physical or pharmacological stress, but echocardiography is excellent at revealing diastolic dysfunction and might also be used to detect systolic dysfunction at rest. Furthermore, measurement of circulating levels of cardiac biomarkers could improve the diagnostic assessm+ent. Cirrhotic cardiomyopathy contributes to various complications in cirrhosis, especially as an important factor in the development of hepatic nephropathy. Additionally, cirrhotic cardiomyopathy seems to be associated with the development of heart failure in relation to invasive procedures such as shunt insertion and liver transplantation. Current pharmacological treatment is nonspecific and directed towards left ventricular failure, and liver transplantation is currently the only proven treatment with specific effect on cirrhotic cardiomyopathy.

Atrial natriuretic peptide affects cardiac remodeling, function, heart failure, and survival in a mouse model of dilated cardiomyopathy

Dilated cardiomyopathy is a frequent cause of heart failure and death. Atrial natriuretic peptide (ANP) is a biomarker of dilated cardiomyopathy, but there is controversy whether ANP modulates the development of heart failure. Therefore, we examined whether ANP affects heart failure, cardiac remodeling, function, and survival in a well-characterized, transgenic model of dilated cardiomyopathy. Mice with dilated cardiomyopathy with normal ANP levels survived longer than mice with partial ANP (P<0.01) or full ANP deficiency (P<0.001). In dilated cardiomyopathy mice, ANP protected against the development of heart failure as indicated by reduced lung water, alveolar congestion, pleural effusions, etc. ANP improved systolic function and reduced cardiomegaly. Pathological cardiac remodeling was diminished in mice with normal ANP as indicated by decreased ventricular interstitial and perivascular fibrosis. Mice with dilated cardiomyopathy and normal ANP levels had better systolic function (P<0.001) than mice with dilated cardiomyopathy and ANP deficiency. Dilated cardiomyopathy was associated with diminished cardiac transcripts for NP receptors A and B in mice with normal ANP and ANP deficiency, but transcripts for NP receptor C and C-type natriuretic peptide were selectively altered in mice with dilated cardiomyopathy and ANP deficiency. Taken together, these data indicate that ANP has potent effects in experimental dilated cardiomyopathy that reduce the development of heart failure, prevent pathological remodeling, preserve systolic function, and reduce mortality. Despite the apparent overlap in physiological function between the NPs, these data suggest that the role of ANP in dilated cardiomyopathy and heart failure is not compensated physiologically by other NPs.

Prognosis value of atrial natriuretic peptide and brain natriuretic peptide for heart failure in patients undergoing allogeneic bone marrow transplantation

It is essential to evaluate the organ function of the recipient before bone marrow transplantation (BMT). This study investigated the usefulness of atrial natriuretic peptide (ANP) and brain natriuretic peptide (BNP) levels as indicators of cardiac function. Seventy-five consecutive patients undergoing allogeneic BMT were enrolled. All of them had an ejection fraction of 55% or more on echocardiography. Six of the 75 patients died of heart failure after transplantation and these 6 patients were compared with the other 69 patients to assess the prognostic value of the two natriuretic peptides. Both peptides remained normal from before conditioning until recovery from leukopenia in all 69 surviving patients. Among the 6 patients who died of heart failure, however, BNP was increased in all 6 patients and ANP was increased in five of them at an average of 43.6 +/- 16.7 days before the onset of heart failure. Monitoring of these peptides may not only be useful for assessment of cardiac function but also for predicting the occurrence of heart failure.

Does depression impact cognitive impairment in patients with heart failure?

Prevalence studies have noted the cooccurrence of cognitive decline and depression in persons with heart failure. Cognitive impairment is associated with significant mortality and deteriorated quality of life, likely due to impairments in memory and executive function, which impact a patient's ability to understand and comply with prescribed treatment plans. This is especially true in complex diseases such as heart failure. Evidence from literature supports the possibility of a pathophysiological relationship between cognitive impairment, depression, and heart failure. Yet, very few studies have sought to investigate this relationship. This paper reviews current literature on the association between depression and cognitive impairment in persons with heart failure and explores possible mechanisms explaining this complex triad.

Decompensated heart failure is associated with reduced corin levels and decreased cleavage of pro-atrial natriuretic peptide

BACKGROUND

By promoting salt and water excretion, the corin and the atrial natriuretic peptide (ANP) system should help to maintain fluid balance in heart failure. Yet, the development of fluid retention despite high levels of ANP-related peptides suggests that this compensatory system is limited.

METHODS AND RESULTS

Levels of circulating corin (the pro-ANP-converting enzyme) and pro-ANP were measured in hospitalized patients with heart failure, using novel immunoassays. Patients (n=14) had severe heart failure (New York Heart Association class III-IV) with a median ejection fraction of 18% and median brain natriuretic peptide levels of 1940 pg/mL. In heart failure, median plasma corin levels were 7.6-fold lower than measured in plasma from 16 normal control subjects (180 versus 1368 pg/mL, P<0.01). In contrast, in patients with heart failure, levels of plasma N-terminal ANP peptides (N-ANP and pro-ANP) levels were markedly elevated (42.0 versus 7.5 ng/mL, P<0.01). Levels of uncleaved pro-ANP, measured by novel immunoassays, were significantly higher in patients with heart failure (P<0.01), suggesting that corin cleavage of pro-ANP was impaired. Median plasma levels of cyclic guanosine monophosphate were elevated in patients with heart failure (150.0 versus 7.6 pmol/mL, P<0.01), and plasma cyclic guanosine monophosphate levels positively correlated with the fractional amount of cleaved pro-ANP (r(s)=0.59, P<0.03) but not with levels of uncleaved pro-ANP, implying that the cellular response to ANP remained intact.

CONCLUSIONS

Taken together, these data suggest that there may be patients for whom low corin levels and impaired pro-ANP cleavage contribute to acute decompensation.

Cardioprotection by a nonerythropoietic, tissue-protective peptide mimicking the 3D structure of erythropoietin

Erythropoietin (EPO), originally identified for its critical hormonal role in regulating production and survival of erythrocytes, is a member of the type 1 cytokine superfamily. Recent studies have shown that EPO has cytoprotective effects in a wide variety of tissues, including the heart, by preventing apoptosis. However, EPO also has undesirable effects, such as thrombogenesis. In the present study, we investigated whether a helix B-surface peptide (HBSP), a nonerythropoietic, tissue-protective peptide mimicking the 3D structure of erythropoietin, protects cardiomyocytes from apoptosis in vitro and in vivo. In cultured neonatal rat cardiomyocytes, HBSP clearly inhibited apoptosis (approximately 80%) induced by TNF-alpha, which was comparable with the effect of EPO, and activated critical signaling pathways of cell survival, including Akt, ERK1/2, and STAT3. Among these pathways, Akt was shown to play an essential role in HBSP-induced prevention of apoptosis, as assessed by using a small interfering RNA approach. In the dilated cardiomyopathic hamster (J2N-k), whose cardiac tissues diffusely expressed TNF-alpha, HBSP also inhibited apoptosis (approximately 70%) and activated Akt in cardiomyocytes. Furthermore, the levels of serum creatine kinase activity and of cardiac expression of atrial natriuretic peptide, a marker of chronic heart failure, were down-regulated in animals treated with HBSP. These data demonstrate that HBSP protects cardiomyocytes from apoptosis and leads to a favorable outcome in failing hearts through an Akt-dependent pathway. Because HBSP does not have the undesirable effects of EPO, it could be a promising alternative for EPO to treat cardiovascular diseases, such as myocardial infarction and heart failure.

Brain natriuretic peptide in pulmonary arterial hypertension: biomarker and potential therapeutic agent

B-type natriuretic peptide (BNP) is a member of the natriuretic peptide family, a group of widely distributed, but evolutionarily conserved, polypeptide mediators that exert myriad cardiovascular effects. BNP is a potent vasodilator with mitogenic, hypertrophic and pro-inflammatory properties that is upregulated in pulmonary hypertensive diseases. Circulating levels of BNP correlate with mean pulmonary arterial pressure (mPAP) and pulmonary vascular resistance (PVR) in patients with pulmonary arterial hypertension (PAH). Elevated plasma BNP levels are associated with increased mortality in patients with PAH and a fall in BNP levels after therapy is associated with improved survival. These findings have important clinical implications in that a noninvasive blood test may be used to identify PAH patients at high-risk of decompensation and to guide pulmonary vasodilator therapy. BNP also has several biologic effects that could be beneficial to patients with PAH. However, lack of a convenient method for achieving sustained increases in circulating BNP levels has impeded the development of BNP as a therapy for treating pulmonary hypertension. New technologies that allow transdermal or oral administration of the natriuretic peptides have the potential to greatly accelerate research into therapeutic use of BNP for cor pulmonale and pulmonary vascular diseases. This review will examine the basic science and clinical research that has led to our understanding of the role of BNP in cardiovascular physiology, its use as a biomarker of right ventricular function and its therapeutic potential for managing patients with pulmonary vascular disease.

Plasma atrial natriuretic peptide in healthy calves and calves with congenital heart disease

BACKGROUND

The basic and clinical implications of evaluating plasma atrial natriuretic peptide (ANP) concentration in calves are unknown.

OBJECTIVE

To investigate the relationship between the plasma ANP concentration and left ventricular end-diastolic pressure (LVEDP) in healthy calves subjected to volume overload (Study 1), and to compare the plasma ANP concentration in calves with or without heart disease (Study 2).

ANIMALS

Six healthy calves were used in Study 1; disease calves and sick calves with (n = 9) and without congenital heart disease (CHD) (n = 9) were used in Study 2.

METHODS

In Study 1, LVEDP in anesthetized calves was manipulated by IV administration of acetated Ringer's solution (rate of 100 mL/kg/h for 20 minutes) and furosemide. In Study 2, disease calves were identified by blood examination and echocardiography or pathological examination. The plasma ANP concentration was determined by a chemiluminescence enzyme immunoassay for human alpha-ANP.

RESULTS

In Study 1, preloading significantly increased the plasma ANP concentration (36 +/- 20-185 +/- 156, P < .01) and LVEDP (-11 +/- 7-2 +/- 12, P < .01) from the baseline. Furthermore, plasma ANP concentrations were strongly correlated with LVEDP (r= 0.61). In Study 2, the plasma ANP concentration was significantly higher in the calves with CHD than in the calves without heart disease (220 [67-970] versus 31 [10-86]; mean [range], P < .001).

CONCLUSIONS AND CLINICAL IMPORTANCE

Measurement of plasma ANP concentrations in calves can provide additional information useful for predicting hemodynamic abnormalities.

Atrial Remodeling And Atrial Fibrillation: Mechanistic Interactions And Clinical Implications

Atrial fibrillation (AF) is the most common arrhythmia in clinical practice. The prevalence of AF increases dramatically with age and is seen in as high as 9% of individuals by the age of 80 years. In high-risk patients, the thromboembolic stroke risk can be as high as 9% per year and is associated with a 2-fold increase in mortality. Although the pathophysiological mechanism underlying the genesis of AF has been the focus of many studies, it remains only partially understood. Conventional theories focused on the presence of multiple re-entrant circuits originating in the atria that are asynchronous and conducted at various velocities through tissues with various refractory periods. Recently, rapidly firing atrial activity in the muscular sleeves at the pulmonary veins ostia or inside the pulmonary veins have been described as potential mechanism,. AF results from a complex interaction between various initiating triggers and development of abnormal atrial tissue substrate. The development of AF leads to structural and electrical changes in the atria, a process known as remodeling. To have effective surgical or catheter ablation of AF good understanding of the possible mechanism(s) is crucial.Once initiated, AF alters atrial electrical and structural properties that promote its maintenance and recurrence. The role of atrial remodeling (AR) in the development and maintenance of AF has been the subject of many animal and human studies over the past 10-15 years. This review will discuss the mechanisms of AR, the structural, electrophysiologic, and neurohormonal changes associated with AR and it is role in initiating and maintaining AF. We will also discuss briefly the role of inflammation in AR and AF initiation and maintenance, as well as, the possible therapeutic interventions to prevent AR, and hence AF, based on the current understanding of the interaction between AF and AR.

Prognostic value of heart rate variability and ventricular arrhythmias during 13-year follow-up in patients with mild to moderate heart failure

BACKGROUND

In contrast to patients with moderate to severe chronic heart failure (CHF), data regarding long-term outcome in patients with mild CHF are scarce. We examined the place of Holter monitoring to study the prognostic value of ventricular arrhythmias and heart rate variability (HRV) in patients with mild to moderate CHF during long-term follow-up.

METHODS

We studied 90 patients with mild to moderate CHF and NYHA class II who had been enrolled in the Dutch Ibopamine Multicenter Trial. At baseline their mean age was 60.5 +/- 8.0 years, left ventricular ejection fraction (LVEF) was 0.29 +/- 0.09, and 85% were males. At the start of the study, patients were only using diuretics, while digoxin, and particularly ACE inhibitors and beta-blockers were initiated later. Univariate and multivariate proportional hazard analyses were performed.

RESULTS

At baseline 80% of patients were in NYHA class II, and 20% were in class III; their mean age was 60 years, mean LVEF was 0.29, and 85% were men. During a follow-up of 13 years, 47 patients (53%) died. Cardiovascular (CV) death occurred in 39 patients, of which 28 were sudden cardiac death (SCD). For both CV death and SCD, LVEF <30% and ventricular premature beats/h (>20) were independent risk markers. Of the HRV parameters, total power (>2,500 ms(2)) was an important risk marker for CV death, but not for SCD.

CONCLUSION

The present 13-year follow-up study in 90 patients with mild to moderate CHF showed that ventricular premature beats and HRV may have important value in predicting outcome.

Comparison of enzymatic recycling electrodes for measuring aminophenol: development of a highly sensitive natriuretic peptide assay system

Several redox enzymes were examined for enzymatic/electrochemical-recycling systems in order to measure p-aminophenol (PAP) with high sensitivity. Glucose oxidase (GOD) and diaphorase (DI) worked well as catalysts for recycling electrode systems: these enzymes effectively reduced p-iminoquinone (PIQ), the electrochemically-oxidized form of PAP, and caused an enhancement in the electrochemical signals (anodic currents in the voltammogram and amperogram) by approximately 100 fold. The lower detection limits for PAP were estimated to be 50 nM with the GOD system and 2 nM with the DI system. We combined the enzymatic-recycling electrode using DI with an enzyme immunoassay system to measure atrial natriuretic peptide (ANP), an important marker peptide hormone involved in heart diseases. ANPs from serum samples at ppt-levels were determined appropriately using the present assay system.

Non-Gaussian heart rate as an independent predictor of mortality in patients with chronic heart failure

BACKGROUND

Morbidity and mortality due to chronic heart failure remain unacceptably high despite effective drug therapies, and the search for a better risk predictor is ongoing. Statistics derived from beat-to-beat fluctuations in heart rate or heart rate variability (HRV) have been used for this purpose, but the current predictability level is low or moderate at best.

OBJECTIVE

The purpose of this study was to evaluate whether a recently proposed non-Gaussian index of HRV is a significant and independent mortality predictor in patients with congestive heart failure (CHF).

METHODS

Twenty-four-hour Holter ECGs from 108 CHF patients were evaluated. Thirty-nine (36.1%) of the patients died during the follow-up period of 33 +/- 17 months. Cox proportional hazards regression analysis was performed to determine factors related to all-cause mortality. The factors evaluated derived from clinical information, including plasma brain natriuretic peptide, conventional time- and frequency-domain and fractal HRV measures, and a recently proposed non-Gaussian index lambda of HRV.

RESULTS

The short-term (<40 beats) non-Gaussian index lambda(40) (hazard ratio per increment of unit standard deviation 1.64, 95% confidence interval [1.23, 2.18], P <.001) and the long-term (<1,000 beats) index lambda(1000) (hazard ratio 1.42, 95% confidence interval [1.07, 2.18], P <.02), together with brain natriuretic peptide (hazard ratio 2.26, 95% confidence interval [1.45, 3.53], P <.001), are significant univariate risk predictors of mortality. In a multivariate model, lambda(40) (1.49, [1.13, 1.96], P <.005) and brain natriuretic peptide (2.39, [1.53, 3.75], P <.001) are independent predictors of the survival statistics of patients. None of the conventional HRV measures have predicted the mortality of patients in a significant and independent manner.

CONCLUSION

The results of this study indicate the usefulness of the short-term non-Gaussian index of HRV for risk prediction in patients with CHF.

Prognostic value of N-terminal pro-B-type natriuretic peptide in patients with active infective endocarditis

Our aim was to determine whether N-terminal pro-B-type natriuretic peptide (NT-pro-BNP) and cardiac troponin I (cTnI) levels are valuable for predicting prognosis in patients with infective endocarditis (IE). We analyzed measured plasma NT-pro-BNP levels at admission in 45 patients with definite IE. The primary end point was early surgery or in-hospital death. The other data recorded were baseline clinical, echocardiographic, and laboratory parameters. Thirty patients underwent early surgery, and 9 died in hospital. Univariate analysis revealed that log NT-pro-BNP, cTnI > or =0.03 ng/ml, New York Heart Association functional class III to IV symptoms, left atrial diameter, left ventricular end-diastolic diameter, left ventricular end-systolic diameter, and severe valvular regurgitation were associated with increased risk of reaching the primary end point. Cox proportional hazard regression analysis identified log NT-pro-BNP (hazard ratio 1.5; 95% confidence interval 1.2 to 1.9, p <0.001) as the only independent predictor of the primary end point. The log NT-pro-BNP cut-off value with the highest sensitivity (97%) and specificity (92%) for predicting primary end point was 7.2 (1,500 pg/ml). Patients with NT-pro-BNP level > or =1,500 pg/ml had significantly lower event-free survival than others. In conclusion, admission NT-pro-BNP is of prognostic value in patients with IE. The combination of admission NT-pro-BNP and cTnI levels appears to have even greater value for risk stratification in this patient group.

Comparative evaluation of B-type natriuretic peptide, mid-regional pro-A-type natriuretic peptide, mid-regional pro-adrenomedullin, and Copeptin to predict 1-year mortality in patients with acute destabilized heart failure

BACKGROUND

The aim of the present study was to evaluate the capability B-type natriuretic peptide (BNP) as a prognostic marker in patients with acute destabilized heart failure in comparison with mid-regional pro-A-type natriuretic peptide (MR-proANP), mid-regional pro-adrenomedullin (MR-proADM), and the C-terminal part of the arginine vasopressin prohormone (Copeptin).

METHODS AND RESULTS

BNP, MR-proANP, MR-proADM, and Copeptin plasma concentrations were obtained in 137 patients with acute destabilized heart failure attending a tertiary care hospital. The end point was defined as all-cause mortality, and the study participants were followed for 365 days. Of the 137 patients enrolled, 41 died and 96 survived during follow-up. ROC curve analysis showed that the areas under curve for the prediction of 1-year mortality were similar for BNP (0.716; 95% CI 0.633-0.790), MR-proANP (0.725; 95% CI 0.642-0.798), MR-proADM (0.708; 95% CI 0.624-0.782), and Copeptin (0.688; 95% CI 0.603-0.764). Using tercile approaches, Kaplan-Meier curve analyses demonstrated that the predictive value of all four analytes for survival probability was comparable (log-rank test for trend, P < .001 for each). In multivariable Cox proportional-hazards regression analyses, increased BNP, MR-proANP, MR-proADM, and Copeptin plasma concentrations were the strongest predictors of mortality.

CONCLUSION

BNP is considered an established prognostic marker for heart failure patients. The present study provides evidence that MR-proANP, MR-proADM, and Copeptin measurements might have similar predictive properties compared with BNP determinations for one-year all-cause mortality in acute destabilized heart failure.

Arginine 16 Glycine β2-Adrenoceptor Polymorphism and Cardiovascular Structure and Function in Patients with Heart Failure

The beta2/beta1 adrenoceptor ratio increases in congestive heart failure (CHF), making the heart relatively more dependent on inotropic, lusitropic, and chronotropic stimulation by the beta2-adrenergic receptor (ADRB2). In healthy human beings, those who are homozygous for arginine (Arg) at amino acid 16 of the ADRB2 have reduced receptor function when compared with individuals homozygous for glycine (Gly) at this position. The cardiovascular effects of the Arg16Gly polymorphism of the ADRB2 in CHF are not well understood. The aim of this study was to examine the influence of common polymorphisms of the ADRB2 on cardiovascular structure and function in patients with CHF. Echocardiography, neurohormonal assays, and exercise tests were performed in 68 healthy individuals and 95 patients with CHF. All of the patients with CHF were stable, New York Heart Association class II to III, of ischemic or nonischemic cause, with an ejection fraction of 40% or less. Of the patients with CHF, 16 were Arg/Arg, 36 were Arg/Gly, and 43 were Gly/Gly at amino acid 16. In those without CHF, the Arg16Gly polymorphism of the ADRB2 had no effect on cardiovascular function. In contrast, in CHF, Arg/Arg homozygotes had higher plasma norepinephrine and atrial natriuretic peptide levels, greater left atrial diastolic dimension, higher peak velocity of early/late diastolic filling ratio, and shorter deceleration time compared with Gly16 homozygotes. Furthermore, Arg16 homozygotes had reduced exercise tolerance compared with Gly16 homozygotes (evidenced by shorter exercise duration and lower peak oxygen consumption per unit time), and a lesser chronotropic response to exercise. In patients with CHF, but not in demographically matched healthy persons, the Arg16Gly polymorphism of the ADRB2 exerts important effects on cardiovascular structure and function, neurohormonal activation, and exercise tolerance.

Brain type natriuretic peptide (BNP)-A marker of new millennium in diagnosis of congestive heart failure

The burden of disease in patients with congestive heart failure is high. The future of BNP looks promising as it may be a better diagnostic tool for the diagnosis of CHF in developing countries in new millennium. Natriuretic peptide hormones, a family of vasoactive peptides with many favourable physiological properties, have emerged as important contenders for development of diagnostic tools and therapeutic agents in cardiovascular disease. Measurement of B-type natriuretic peptide has become as an easy-to-perform bedside test. The clinical and diagnostic significance of the measurement of plasma Nt-proBNP in the diseases of the cardiovascular system with particular emphasis on the assessment of patients with heart failure and their effects on predicting survival rate. The plasma levels of Nt-proBrain Natriuretic peptide responds more vigorously after myocardial infarction than those of other natriuretic peptides. This article is an attempt to give a short overview on the utility of BNP-blood levels for the diagnosis and treatment of heart failure.

Class II HDACs mediate CaMK-dependent signaling to NRSF in ventricular myocytes

We recently reported that a transcriptional repressor, neuron-restrictive silencer factor (NRSF), represses expression of fetal cardiac genes, including atrial and brain natriuretic peptide (ANP and BNP), by recruiting class I histone deacetylase (HDAC) and that attenuation of NRSF-mediated repression contributes to the reactivation of fetal gene expression during cardiac hypertrophy. The molecular mechanism by which the activity of the NRSF-HDAC complex is inhibited in cardiac hypertrophy remains unresolved, however. In the present study, we show that class II HDACs (HDAC4 and 5), which are Ca/calmodulin-dependent kinase (CaMK)-responsive repressors of hypertrophic signaling, associate with NRSF and participate in NRSF-mediated repression. Blockade of the CaMK-class II HDAC signaling pathway using a CaMK-resistant HDAC5 mutant, a CaMK inhibitor (KN62) or a dominant-negative CaMK mutant inhibited ET-1-inducible ANP and BNP promoter activity, but that inhibitory effect was abolished by mutation of the neuron-restrictive silencer element (NRSE) within the ANP and BNP promoter. In addition, adenovirus-mediated expression of a dominant-negative NRSF mutant abolished the inhibitory effect of KN62 on ET-1-inducible endogenous ANP gene expression in ventricular myocytes. Finally, the interaction between NRSF and class II HDACs was decreased in both in vitro and in vivo models of cardiac hypertrophy. These findings show that ET-1-induced CaMK signaling disrupts class II HDAC-NRSF repressor complexes, thereby enabling activation of ANP and BNP gene transcription in ventricular myocytes, and shed light on a novel mechanism by which the fetal cardiac gene program is reactivated.

The value of cardiopulmonary exercise testing and brain natriuretic peptide plasma levels in predicting the prognosis of patients with chronic heart failure

BACKGROUND

A peak VO2 above 14 ml/min/kg at cardiopulmonary exercise testing and brain natriuretic peptide (BNP) levels is used to estimate survival in patients with chronic heart failure (CHF). Limited data, however, exist comparing the prognostic value of both markers simultaneously in patients with mild to moderate CHF.

METHODS

We prospectively studied 85 consecutive patients (59+/-13 years, 63 men) with CHF (mean LVEF 26+/-6%). All patients underwent cardiopulmonary exercise testing with determination of peak VO2 and measurement of plasma BNP at rest. The incidence of cardiac decompensation and cardiac death was recorded in the follow-up.

RESULTS

During a mean follow-up of 427+/-150 days, four deaths and ten cardiac decompensations occurred. Kaplan-Meier estimates of freedom from clinical events differed significantly for patients above and below the median BNP of 292 pg/ml and also for patients above and below a peak VO2 of 14 ml/min/kg (p<0.05 each). BNP and peak VO2 (area under the ROC 0.75 vs. 0.72) showed a comparable discrimination of CHF patients with adverse cardiac events. The prognostic information of BNP was at least as powerful as that derived from peak VO2. A BNP above 324 pg/ml was associated with a risk ratio of 8.8 for adverse cardiac events.

CONCLUSIONS

In patients with mild to moderate CHF, BNP measurements appear to be an alternative to peak VO2 determined by cardiopulmonary exercise testing for the assessment of prognosis in CHF. BNP may facilitate the ambulatory management of patients with mild to moderate CHF since it is less expensive, less time-consuming, and free of procedural risk compared to exercise testing.

Electrical and Structural Remodeling: Role in the Genesis and Maintenance of Atrial Fibrillation

Atrial fibrillation (AF) and congestive heart failure (CHF) are 2 frequently encountered conditions in clinical practice. Both lead to changes in atrial function and structure, an array of processes known as atrial remodeling. This review provides an overview of ionic, electrical, contractile, neurohumoral, and structural atrial changes responsible for initiation and maintenance of AF. In the last decade, many studies have evaluated atrial remodeling due to AF or CHF. Both conditions often coexist, which makes it difficult to distinguish the contribution of each. Because of atrial stretch in the setting of hypertension or CHF, atrial remodeling frequently occurs long before AF arises. Alternatively, AF may lead to electrical remodeling, that is, shortening of refractoriness due to the high atrial rate itself. In many experimental AF or rapid atrial pacing studies, the ventricular rate was uncontrolled. In those studies, atrial stretch due to CHF may have interfered with the high atrial rate to produce a mixed type of electrical and structural remodeling. Other studies have dissected the individual role of AF or atrial tachycardia from the role CHF plays in atrial remodeling. Atrial fibrillation itself does not lead to structural remodeling, whereas this is frequently produced by hypertension or CHF, even in the absence of AF. Primary and secondary prevention programs should tailor treatment to the various types of remodeling.

Increased circulating big endothelin-1, endothelin-1 and atrial natriuretic peptide in infants and children with heart failure secondary to congenital heart disease

In order to characterize the changes of five neurohormones in pediatric patients with varying degrees of congestive heart failure (CHF) secondary to congenital heart disease (CHD), we measured plasma neurohormone levels by using radioimmunoassay or high-performance liquid chromatography in 81 subjects including 13 normal children and 68 pediatric patients with CHD. Patients with CHF (n=27) had elevated levels of big endothelin-1 (big ET-1) (29.5+/-1.6 vs. 18.1+/-2.1 pg/ml, p<0.001), endothelin-1 (ET-1) (17.9+/-1.7 vs. 7.8+/-1.7 pg/ml, p<0.001) and norepinephrine (505.6+/-65.6 vs. 219.6+/-23.3 pg/ml, p<0.01) as compared with healthy control subjects (n=13). Plasma norepinephrine levels (505.6+/-65.6 vs. 230.0+/-8.0 pg/ml, p<0.001) and atrial natriuretic peptide (35.5+/-4.2 vs. 7.6+/-0.6 pg/ml, p<0.001) in the 27 patients with CHF were significantly higher than in the 41 patients without CHF. There was also a highly significant stepwise increase in big ET-1, atrial natriuretic peptide and norepinephrine according to the severity of heart failure. Our results suggest that increased circulating neurohormonal activity in CHD relates to the presence and clinical severity of heart failure in children. Plasma levels of big ET-1 and ET-1 were not only significant markers of CHF but also correlated well with the severity of CHF in CHD with left-to-right shunt.

Cardiac resynchronization induces favorable neurohumoral changes

AIM

The aim of this article is to examine whether cardiac resynchronization therapy (CRT) induces improvements in the neurohumoral system.

METHODS AND RESULTS

Thirteen patients with HF (left ventricular (LV) ejection fraction <35%) were included. Before and after 6 months of CRT, myocardial (123)I-metaiodobenzylguanidine ((123)I-MIBG) uptake indices, used as an index of neural norepinephrine reuptake and retention, and brain natriuretic peptide (BNP) levels, used as an index of LV end-diastolic pressure, NYHA classification and echocardiographic indices were assessed. Six months of CRT resulted in significant improvement in (1) NYHA classification and reduction in QRS width (P < 0.001), (2) decrease of LV end-diastolic diameter (P = 0.005), LV end-systolic diameter (P = 0.005), septal to lateral delay (P = 0.01) and mitral regurgitation (MR, P = 0.04), (3) delayed (123)I-MIBG heart/mediastinum ratios improved (P = 0.03) and (123)I-MIBG washout decreased (P = 0.001), and (4) BNP levels decreased (P = 0.001).

CONCLUSIONS

Parallel to significant functional improvement and echocardiographic reverse remodeling and resynchronization, our data indicate that CRT induces favorable changes in the neurohumoral system.

Hormonal responses to the 6-minute walk test in women and men with coronary heart disease: a pilot study

BACKGROUND

Women with coronary heart disease (CHD) are more likely than men to develop congestive heart failure (CHF). Dysregulation of sympathetic and volume-regulatory hormones may contribute to the onset of symptomatic CHF. We hypothesized that this hormonal dysregulation develops at an earlier stage of CHD in women than in men.

OBJECTIVES

The study goals were (1) to determine the effect of gender on basal and exercise-induced plasma concentrations of catecholamines and volume-regulatory hormones in patients diagnosed with CHD, New York Heart Association class I and (2) to determine efficacy of the 6-minute walk test as a stimulus for release of these hormones.

METHODS

Study participants were 9 women and 9 men with normal left ventricular ejection fraction (>50%) and CHD confirmed by arteriography. Data were collected under resting conditions, and after the 6-minute walk test, in the general clinical research center of a northeastern university medical center.

RESULTS

Basal plasma vasopressin (VP) concentration was significantly higher in men than in women (P = .018). Exercise, for women and men combined, significantly increased atrial natriuretic peptide (P < .0005), VP (P = .04), norepinephrine (P < .0005), and epinephrine (P = .038) but not plasma renin activity (P = .09). No further gender differences were detected for basal levels, or for the magnitude of exercise-induced increases, for any of the hormones measured.

CONCLUSIONS

The 6-minute walk test is an exercise of sufficient intensity and duration to initiate the release of hormones associated with sympathetic activation and fluid-electrolyte regulation in both women and men with CHD. It appears that a gender difference was detected only for basal VP levels.

Carvedilol therapy is associated with a sustained decline in brain natriuretic peptide levels in patients with congestive heart failure

BACKGROUND

Beta-blocker therapy improves symptoms, left ventricular ejection fraction (LVEF), and survival in patients with congestive heart failure, but chronic effects on neurohormones have not been extensively investigated. Therefore, we examined the neurohumoral effects of carvedilol.

METHODS

Fifty-five patients with New York Heart Association (NYHA) classes II-III congestive heart failure and LVEF < or =35% entered the study with intention to assess LVEF, NYHA class, plasma brain natriuretic peptide (BNP), N-terminal atrial natriuretic peptide (NANP), big-endothelin, endothelin-1, norepinephrine, and angiotensin II at baseline and at 6 and 12 months after initiation of carvedilol.

RESULTS

Forty-six patients completed 12 months of follow-up. Left ventricular ejection fraction improved from 26% +/- 8% at baseline to 39% +/- 14% at 12 months. New York Heart Association class improved from 2.3 +/- 0.4 at baseline to 1.8 +/- 0.7 at 12 months. Brain natriuretic peptide fell from 453 +/- 784 to 208 +/- 393 pg/mL at 6 months and 223 +/- 334 pg/mL at 12 months ( P = .01 vs baseline). N-terminal atrial natriuretic peptide did not change between baseline and 6 months but fell at 12 months (2117 +/- 1678, 2015 +/- 1532, and 1438 +/- 1442 pg/mL, respectively, P = .001 between baseline and 12 months). Angiotensin II was lower at 6 and 12 months than at baseline (12.6 +/- 10, 7.8 +/- 5.5 pg/mL, P < 0.001, and 11.3 +/- 17.1 pg/mL, P = .02, respectively). Left ventricular ejection fraction at 12 months correlated inversely with BNP level at 12 months (r = -0.55, P = .001).

CONCLUSIONS

Carvedilol therapy is associated with a sustained decline in BNP and NANP levels. Serial BNP levels can provide some guidance regarding probability of LVEF improvement, but the relationship is not strong enough for BNP levels to supplant measurement of LVEF.