Recombinant B-type Natriuretic Peptide Nesiritide Attenuates Vascular Remodelling by Reducing Plasma Aldosterone in Rabbits

B-type natriuretic peptide prevents postnatal closure of ductus arteriosus by both vasodilation and anti-remodeling in neonatal rats

The physiologic process of postnatal ductus arteriosus (DA) closure consists of vasoconstriction followed by vascular remodeling. We have recently reported that B-type natriuretic peptide (BNP), a potent vasodilator, also has anti-remodeling effects in pulmonary vasculature. However, its effects on DA have not been elucidated. We investigated whether BNP can prevent DA closure, and if so, the underlying mechanisms. Using in vivo studies, we examined effects of BNP (10 mg/kg, ip at birth) on DA closure in neonatal rats within 4 h after birth. We found that in control rats, the DA spontaneously closed at 4 h with a decreased DA diameter, enhanced intimal thickening, and luminal occlusion. BNP prevented DA closure at 4 h with a preserved DA diameter, attenuated intimal thickening, and preserved luminal patency. Ex vivo, BNP attenuated oxygen-induced vasoconstriction of isolated DA rings of newborn rats. These vasodilating effects were blunted by Rp-8-Br-PET-cGMPS, a cGMP inhibitor. In vitro, BNP inhibited angiotensin II (Ang II)-induced proliferation and migration of DA smooth muscle cells (DASMCs). BNP inhibited Ang II-induced mitochondrial reactive oxygen species (ROS) production and calcium overload in DASMCs. Finally, BNP inhibited Ang II-induced ERK1/2 activation. These in vitro effects were antagonized by Rp-8-Br-PET-cGMPS. In conclusion, BNP prevents postnatal DA closure by both vasodilation and anti-remodeling through the cGMP pathway. The mechanisms underlying anti-remodeling effects include anti-poliferation and anti-migration, with attenuation of mitochondrial ROS production and intracellular calcium and ERK1/2 signaling. Therefore, the BNP/cGMP pathway can be a promising therapeutic target for clinical management of DA patency.

Nesiritide Therapy Is Associated With Better Clinical Outcomes Than Dobutamine Therapy in Heart Failure

To evaluate the therapeutic effects of dobutamine and nesiritide in the treatment of heart failure (HF), a meta-analysis of published studies was conducted. Computerized bibliographic databases in Chinese and English languages were carefully searched to identify the relevant literature. A total of 6 cohort studies were enrolled in current meta-analysis for statistical analyses. The effect of dobutamine and nesiritide in patients with HF was estimated by odds ratios (ORs) and 95% confidence interval (CI). Our results revealed a significantly higher survival rate in nesiritide-treated patients, compared with those treated with dobutamine (OR = 1.97; 95% CI, 1.43-2.71; P < 0.001). In addition, a lower readmission rate was also associated with the nesiritide-treated group in comparison with the dobutamine-treated group (OR = 1.96; 95% CI, 1.39-2.78; P < 0.001). A stratified analysis revealed that the subgroup of patients with HF treated with nesiritide showed higher survival outcomes than those patients with HF treated with dobutamine when follow-up period was greater than 6 months (OR = 1.70; 95% CI, 1.21-2.38; P = 0.002) but not under 6 months (P > 0.05). This indicated that nesiritide treatment had longer term benefits as well. Interestingly, based on the reason for readmission, a subgroup analysis of the HF subgroup and the "all-cause" subgroup showed that higher readmission rates were associated with dobutamine treatment in both subgroups (HF: OR = 2.71; 95% CI, = 1.51-4.83; P = 0.001; all-cause: OR = 1.64; 95% CI, 1.06-2.53; P = 0.026; respectively). Our results suggest that nesiritide therapy is associated with a lower in-hospital mortality rates and decreased readmission rates compared with dobutamine treatment in patients with HF.

Altered relation of the renin-aldosterone system and vasoactive peptides in type 2 diabetes: The KORA F4 study

BACKGROUND AND AIMS

The exact mechanism of premature atherosclerosis in diabetes is still unclear. Inappropriate activation of the renin-aldosterone-angiotensin system may be an important risk factor for cardiovascular disease. We investigated whether renin and aldosterone are associated with vasoactive peptides midregional-pro atrial natriuretic peptide (MR-proANP) and midregional-pro adrenomedullin (MR-proADM), or with intima media thickness (IMT) as a marker for early atherosclerotic alterations in the general community and in subjects with type 2 diabetes.

METHODS

In 1261 participants in the KORA F4 study, the associations of renin, aldosterone and aldosterone to renin ratio with MR-proANP, MR-proADM and IMT were assessed using linear regression models stratified for the presence of prediabetes and type 2 diabetes.

RESULTS

After adjustment for confounding factors, an inverse association of MR-proANP with renin (p = 0.002) and aldosterone (p = 0.021) and a direct association of MR-proADM with renin (p < 0.001) and aldosterone (p = 0.019) were seen in nondiabetic individuals. In diabetic subjects, there was no significant correlation of MR-proANP or MR-proADM with renin or aldosterone. Renin and aldosterone were not directly associated with IMT in non-diabetic subjects and the total cohort, whereas aldosterone was associated with IMT in diabetic participants (p = 0.005).

CONCLUSIONS

This study shows associations between renin, aldosterone and MR-proANP/MR-proADM plasma levels that are altered in type 2 diabetes. Plasma renin and aldosterone are not independent biomarkers for early atherosclerotic damages of the carotid arteries in the general community.

Reduced immunoreactivities of B-type natriuretic peptide in pulmonary arterial hypertension rats after ranolazine treatment

Pulmonary arterial hypertension (PAH) is a severe pulmonary vascular disease characterized by sustained increase in the pulmonary arterial pressure and excessive thickening and remodeling of the distal small pulmonary arteries. During disease progression, structural remodeling of the right ventricular (RV) impairs pump function, creates pro-arrhythmic substrates and triggers for arrhythmias. Notably, RV failure and lethal arrhythmias are major contributors to cardiac death in PAH that are not directly addressed by currently available therapies. Ranolazine (RAN) is an anti-anginal, anti-ischemic drug that has cardioprotective effects of heart dysfunction. RAN also has anti-arrhythmic effects due to inhibition of the late sodium current in cardiomyocytes. Therefore, we hypothesized that RAN could reduce the mal-adaptive structural remodeling of the RV, and prevent triggered ventricular arrhythmias in the monocrotaline-induced rat model of PAH. RAN reduced ventricular hypertrophy, reduced levels of B-type natriuretic peptide, and decreased the expression of fibrosis. In addition, RAN prevented cardiovascular death in rat model of PAH. These results support the notion that RAN can improve the functional properties of the RV, highlighting its potential benefits in the setting of heart impairment.

Dobutamine Therapy is Associated with Worse Clinical Outcomes Compared with Nesiritide Therapy for Acute Decompensated Heart Failure: A Systematic Review and Meta-Analysis

BACKGROUND

Inotropes and natriuretic peptides are essential components of current therapeutic options for acute decompensated heart failure (ADHF). This systematic review examines the therapeutic effectiveness of dobutamine and brain natriuretic peptide, nesiritide, in reducing mortality and readmission rates for ADHF treatment.

METHODS

Published studies related to dobutamine and nesiritide therapy in ADHF were identified via an exhaustive search of scientific literature databases. The identified studies, published between 2002 and 2012, were carefully screened based on our predefined inclusion criteria. Selected studies were pooled, and odds ratios (ORs) and 95% confidence intervals (95% CI) for each outcome were calculated. Subgroup analysis was conducted to assess the influence of ethnicity on the study outcome.

RESULTS

Seven cohort studies were selected for this meta-analysis. These seven studies included 959 ADHF patients who underwent nesiritide treatment and 1748 ADHF patients who received dobutamine therapy. Our meta-analysis revealed a significantly lower survival rate in dobutamine-treated patients compared with nesiritide-treated patients (OR 0.48, 95% CI 0.36-0.63, P < 0.001). Additionally, a markedly higher readmission rate was associated with dobutamine treatment compared with nesiritide treatment (OR 0.52, 95% CI 0.36-0.73, P < 0.001). A stratified analysis based on ethnicity revealed a significantly lower survival in dobutamine-treated ADHF patients in Caucasian and mixed populations compared with nesiritide treatment (Caucasian: OR 0.60, 95% CI 0.38-0.94, P = 0.024; Mixed: OR 0.38, 95% CI 0.26-0.56, P < 0.001). However, a similar association was not detected in Asian populations (P = 0.738). Further, dobutamine-treated ADHF patients displayed higher readmission rates than did nesiritide-treated patients in both Caucasian and mixed-race populations (all P < 0.05).

CONCLUSIONS

Our study suggests that dobutamine therapy is associated with poorer outcomes, with higher in-hospital mortality rates and increased readmission rates compared with nesiritide therapy in ADHF patients. Thus, current treatment strategies need to be redesigned for better outcomes.

Retraction. rhBNP therapy can improve clinical outcomes and reduce in-hospital mortality compared with dobutamine in heart failure patients: a meta-analysis

AIMS

A meta-analysis was performed to compare the therapeutic outcomes in patients treated for heart failure (HF) with recombinant human brain natriuretic peptide (rhBNP) and dobutamine.

METHODS

PubMed, Embase and the Chinese Biomedical Database were exhaustively searched to identify studies relevant to this meta-analysis. Eight cohort studies were found suitable for inclusion. Data regarding trial validity, methodological processes and clinical outcomes were extracted.

RESULTS

Patients treated with rhBNP showed statistically significant reduction of in-hospital mortality and re-admission rates compared with the dobutamine treated patient group (both P < 0.05). Further, the rhBNP treated patient group showed higher survival outcomes, compared with dobutamine treated patients, when the post-treatment follow-up period was longer than 6 months (P < 0.05). Stratified analysis based on ethnicity showed a dramatic decrease of in-hospital mortality among mixed race HF patients receiving rhBNP treatment (P < 0.05), but such decreases were not statistically significant in Asian and Caucasian populations (both P > 0.05). On the other hand, re-admission rates were significantly lower in rhBNP treated Caucasian and mixed race populations (both P < 0.05). Notably, in rhBNP treated group, dose levels of 0.015 and 0.03 incrementally lowered the re-admission rates, displaying dose effect, and the re-admission rates at both rhBNP doses were significantly lower than the dobutamine treated group (both P < 0.05).

CONCLUSIONS

Our meta-analysis results suggested that rhBNP therapy is associated with lower in-hospital mortality and re-admission rates in HF patients compared to the dobutamine regimen. Nevertheless, large scale prospective, randomized trials are necessary to confirm these findings.

B-type natriuretic peptide inhibits angiotensin II-induced proliferation and migration of pulmonary arterial smooth muscle cells

Pulmonary vascular remodeling, characterized by disordered proliferation and migration of pulmonary arterial smooth muscle cells (PASMCs), is a pathognomonic feature of pulmonary arterial hypertension. Thus, pharmacologic strategy targeting on anti-proliferation and anti-migration of PASMCs may have therapeutic implications for PAH. Here we investigated the effects and underlying mechanisms of B-type natriuretic peptide (BNP) on angiotensin II (Ang II)-induced proliferation and migration of PASMCs. Proliferation and migration of PASMCs cultured from Wistar rats were induced by Ang II, with or without BNP treatment. In addition, potential underlying mechanisms including cell cycle progression, Ca(2+) overload, reactive oxygen species (ROS) production, signal transduction of MAPK and Akt, and the cGMP/PKG pathway were examined. We found that BNP inhibited Ang II-induced PASMCs proliferation and migration dose dependently. BNP could also arrest the cell cycle progression in the G0/G1-phase. In addition, BNP attenuated intracellular calcium overload caused by Ang II. Moreover, Ang II-induced ROS production was mitigated by BNP, with associated down-regulation of NAD(P)H oxidase 1 (Nox1) and reduced mitochondrial ROS production. Finally, Ang II-activated MAPKs and Akt were also counteracted by BNP. Of note, all these effects of BNP were abolished by a PKG inhibitor (Rp-8-Br-PET-cGMPS). In conclusion, BNP inhibits Ang II-induced PASMCs proliferation and migration. These effects are potentially mediated by decreased calcium influx, reduced ROS production by Nox1 and mitochondria, and down-regulation of MAPK and Akt signal transduction, through the cGMP/PKG pathway. Therefore, this study implicates that BNP may have a therapeutic role in pulmonary vascular remodeling.