Brain natriuretic peptide: role in cardiovascular and volume homeostasis

The Balance Between the Natriuretic Peptides and the Renin-Angiotensin-Aldosterone System in the Preservation of Ideal Cardiovascular Health

A healthy lifestyle plays a key role for maintaining the cardiovascular health (CVH) status and prevent cardiovascular disease occurrence. In fact, a healthy lifestyle was included in the AHA Cardiovascular Health score (Life's Simple 7 [LS7]), subsequently updated to Life's Simple 8 [LS8]. Apart from the importance of controlling conventional cardiovascular risk factors, increasing evidence supports the contributory role of cardiovascular hormones. Higher levels of natriuretic peptides (NPs) and lower levels of renin and aldosterone were significantly associated to CVH. NT-proBNP levels showed a direct relationship with CVH scores in large general Caucasian populations, being also a marker of CVH changes and a predictor of future adverse events. On the other hand, renin and aldosterone were inversely related to CVH scores. In contrast, the counter-regulatory angiotensins [Ang (1-7) acting through Mas receptor, Ang (1-9) acting through Angiotensin Type 2 receptor, and alamandine] strengthen the beneficial properties of NPs. This evidence can be explained by both the effects on systemic hemodynamic and possible pleiotropic local functions regulating different pathways involved in the maintenance of CVH. Based on the current evidence, circulating levels of NT-proBNP, renin and aldosterone may affect CVH in apparently asymptomatic individuals and represent additional markers of residual cardiovascular risk.

Mechanisms for the cardiovascular effects of glucagon-like peptide-1

Over the past three decades, at least 10 hormones secreted by the enteroendocrine cells have been discovered, which directly affect the cardiovascular system through their innate receptors expressed in the heart and blood vessels or through a neural mechanism. Glucagon-like peptide-1 (GLP-1), an important incretin, is perhaps best studied of these gut-derived hormones with important cardiovascular effects. In this review, I have discussed the mechanism of GLP-1 release from the enteroendocrine L-cells and its physiological effects on the cardiovascular system. Current evidence suggests that GLP-1 has positive inotropic and chronotropic effects on the heart and may be important in preserving left ventricular structure and function by direct and indirect mechanisms. The direct effects of GLP-1 in the heart may be mediated through GLP-1R expressed in atria as well as arteries and arterioles in the left ventricle and mainly involve in the activation of multiple pro-survival kinases and enhanced energy utilization. There is also good evidence to support the involvement of a second, yet to be identified, GLP-1 receptor. Further, GLP-1(9-36)amide, which was previously thought to be the inactive metabolite of the active GLP-1(7-36)amide, may also have direct cardioprotective effects. GLP-1's action on GLP-1R expressed in the central nervous system, kidney, vasculature and the pancreas may indirectly contribute to its cardioprotective effects.

Relationship of N-Terminal fragment of Pro-B-Type Natriuretic Peptide and copeptin with erythrocytes-related parameters: A population-based study

BACKGROUND

Plasma levels of natriuretic peptides (NP) have been inversely related to hemoglobin (Hb) concentration in prior studies. However, the mechanism underlying this association remains unclear. We aimed to obtain further insights into potential mechanisms for this correlation in a cohort of healthy adults.

METHODS

A population-based study was performed among 2113 healthy adults aged 25-41years. Relationships of N-Terminal fragment of Pro-B-Type Natriuretic Peptide (NT-proBNP) or copeptin with volume-dependent (Hb, hematocrit (Hct), erythrocyte count (EC), mean corpuscular Hb concentration (MCHC)) and volume-independent (mean corpuscular volume (MCV), mean corpuscular Hb (MCH)) erythrocyte-related parameters were assessed using sex-specific multivariable linear regression analyses.

RESULTS

The median age was 36.7years. Median NT-proBNP (ng/L) levels were 49.5 and 20 among women and men, respectively (p<0.0001). Mean (standard deviation) Hb (g/L) levels were 130.1(9.1) and 149.7(8.6) among women and men, respectively (p<0.0001). Among men, multivariable adjusted β-coefficients (95% confidence interval) for NT-proBNP were -1.68 (-2.36; -1.01), p<0.0001 for Hb; -0.38 (-0.57; -0.20), p<0.0001 for Hct; -0.06 (-0.09; -0.04), p<0.0001 for EC; -0.78 (-1.50; -0.07), p=0.03 for MCHC; 0.26 (-0.04; 0.56), p=0.09 for MCV; and 0.03 (-0.08; 0.14), p=0.61 for MCH. For copeptin, these relationships were 1.36 (0.39; 2.32), p=0.006; 0.41 (0.15; 0.68), p=0.002; 0.06 (0.02; 0.09), p=0.002; -0.17 (-1.19; 0.86), p=0.75; -0.12 (-0.55; 0.31), p=0.58 and -0.05 (-0.21; 0.10), p=0.52. Similar results were observed among women.

CONCLUSIONS

We found significant relationships of NT-proBNP and copeptin with volume-dependent but not volume-independent erythrocyte-related parameters, suggesting that hemodilution may at least in part explain these associations.

Levels of N-terminal pro brain natriuretic peptide are enhanced in people with the uncomplicated metabolic syndrome: a case-cohort analysis of the population-based Casale Monferrato study

BACKGROUND

Both metabolic syndrome (MetS) and N-amino terminal fragment of the prohormone B-type natriuretic peptide (NT-proBNP) confer increased risk of cardiovascular diseases (CVD). We assessed if NT-proBNP levels were greater in people with uncomplicated MetS, who had neither CVD/chronic kidney disease (CKD) nor diabetes, as compared with subjects who met none of the defining criteria of the MetS.

METHODS

A case-cohort study from the non-diabetic population-based Casale Monferrato study was performed, after exclusion of all subjects with established CVD, CKD [estimated glomerular filtration rate (eGFR) < 60 mL/min/1.73 m(2)], and CRP values ≥3 mg/L. Cases (n = 161) with MetS were compared with all subjects within the cohort (n = 124) who were completely free of any component of the MetS. Serum NT-proBNP was centrally measured by immunoenzymatic assay.

RESULTS

NT-proBNP levels were significantly higher in cases than in control subjects [35.4 (15.5-98.2) vs 24.4 (11.7-49.6) pg/mL, p = 0.014]. In logistic regression analysis, compared with NT-proBNP values in the lower quartiles (≤49.64 pg/mL), higher values conferred odds ratio 4.17 (1.30-13.44) of having the MetS, independently of age, sex, microalbuminuria, CRP, eGFR, and central obesity. This association was evident even after the exclusion of hypertensive subjects. Further adjustment for log-HOMA and diastolic blood pressure did not modify the strength of the association, while central obesity was a negative confounder.

CONCLUSIONS

Compared with people without any component of the MetS, those with uncomplicated MetS, who had neither CVD/CKD nor diabetes, had increased NT-proBNP values, even if they were normotensive and although absolute values were still in the low range. The insulin resistance state did not mediate this association, while central obesity was a negative confounder.

N-terminal B-type natriuretic peptide levels in pediatric patients with congestive heart failure undergoing cardiac surgery

OBJECTIVES

The objectives of this study were to measure circulating N-terminal B-type natriuretic peptide levels in pediatric patients undergoing surgical repair of congenital heart lesions with left ventricular volume overload and to determine whether presurgical and immediate postoperative N-terminal B-type natriuretic peptide levels could predict patient outcomes after surgical intervention.

METHODS

Thirty-eight children aged 1 to 36 months undergoing surgical repair of cardiac lesions with left ventricular volume overload were studied. Plasma N-terminal B-type natriuretic peptide levels were measured preoperatively and at 2, 12, 24, 48, and 72 hours after surgical intervention and were assessed for their predictive value of postoperative outcomes. Plasma N-terminal B-type natriuretic peptide levels were also measured in 34 similarly aged healthy children.

RESULTS

Patient preoperative N-terminal B-type natriuretic peptide levels were significantly higher than those of healthy control subjects (3085 +/- 4046 vs 105 +/- 78 pg/mL). Preoperative N-terminal B-type natriuretic peptide levels correlated with the complexity of surgical repair, as measured by cardiopulmonary bypass time (r = 0.529, P < .001), and with postoperative measures, including fractional inhaled oxygen requirements registered at 12 hours (r = 0.443, P = .005) and duration of mechanical ventilation (r = 0.445, P = .005). Plasma N-terminal B-type natriuretic peptide levels increased 5-fold within 12 hours after cardiopulmonary bypass (14,685 +/- 14,317 pg/mL). Multivariable regression analysis showed that the preoperative N-terminal B-type natriuretic peptide level was a significant predictor of duration of intensive care unit stay (P = .02) and that the peak postoperative N-terminal B-type natriuretic peptide level was a significant predictor of the intensity of overall medical management, as assessed by using the therapeutic intervention scoring system (P = .01).

CONCLUSION

Plasma N-terminal B-type natriuretic peptide levels measured preoperatively and postoperatively can be a prognostic indicator in the management of the pediatric patient after surgical intervention for congenital heart repair.

Assessing cardiovascular risk in children with chronic kidney disease. B-type natriuretic peptide: a potential new marker

Elevated plasma B-type natriuretic peptide (BNP) level is a hallmark of altered left ventricular (LV) structure and function. Measurement of circulating BNP has proved to be a sensitive and specific diagnostic test for congestive heart failure (CHF) and coronary syndrome in adults. Further, BNP levels constitute a strong predictive marker for future cardiovascular (CV) events. In high CV risk populations, such as adults with hypertension or chronic kidney disease (CKD), increased BNP predicts CV morbidity and mortality in symptomatic or asymptomatic patients. However, caution is needed in interpreting plasma BNP levels, as they increase with both age and decreased renal function. Despite increasing evidence of the value of BNP in the medical literature in adults, data in children are limited to those with congenital heart disease. It is appropriate to analyze the potential application of this tool in children with CKD, a well-known factor for CV disease.

Role of B-Type Natriuretic Peptide and Effect of Nesiritide After Total Cardiac Replacement With the AbioCor Total Artificial Heart

Endogenous B-type natriuretic peptide (BNP) is thought to be produced in the cardiac ventricles. After sub-total cardiectomy and implantation of a total artificial heart (TAH), the abrupt withdrawal of BNP impairs renal function despite normal hemodynamic variables. We hypothesized that abrupt withdrawal of endogenous BNP may impair renal function and volume homeostasis and BNP may have a direct renal influence unrelated to its cardiovascular effect. Nesiritide infusion should be supplemented in the interim and weaned slowly until BNP levels normalize, which suggests that BNP is produced in tissues other than the cardiac ventricles.

Dysfunction of atrial and B-type natriuretic peptides in congenital univentricular defects

OBJECTIVE

To examine whether children with univentricular defects have intrinsic dysfunction in the natriuretic peptide system.

METHODS

We compared plasma levels of the fluid-regulating hormone vasopressin (antidiuretic hormone), aldosterone, atrial natriuretic peptide, and brain natriuretic peptide in children with congenital univentricular and biventricular defects. We enrolled 27 patients with univentricular defects and 27 patients with biventricular cardiac defects. Children who underwent Fontan and Glenn procedures were considered as patients with univentricular cardiac defects; children who underwent repair of tetralogy of Fallot or subaortic stenosis were considered as controls with biventricular defects.

RESULTS

Preoperative plasma atrial natriuretic peptide, brain natriuretic peptide, antidiuretic hormone, and aldosterone were comparable in both groups. Although plasma cyclic guanosine monophosphate levels were comparable between groups, there was a significant correlation between molar concentrations of plasma cyclic guanosine monophosphate and plasma atrial natriuretic peptide ( r = 0.42) and brain natriuretic peptide ( r = 0.44) in the biventricular group, but not in the univentricular group ( r = 0.19 for atrial natriuretic peptide; r = 0.13 for brain natriuretic peptide). All patients had a significant postoperative increase in plasma antidiuretic hormone. A significant postoperative increase in plasma brain natriuretic peptide was found in the patients with biventricular, but not univentricular, defects. In contrast, a significant increase in plasma aldosterone was observed only in the patients with univentricular defects.

CONCLUSIONS

There were distinct differences between univentricular and biventricular groups in their perioperative plasma fluid-regulating hormone responses. Specifically, patients with univentricular defects may have abnormal natriuretic peptide secretion and function. The natriuretic dysfunction may be on the basis of hypoplastic ventricular development.