Sex-specific mortality prediction by pro-C-type natriuretic peptide measurement in a prospective cohort of patients with ST-elevation myocardial infarction

Impact of obesity on infarct size, circulating biomarkers, mitochondrial function and mortality in a Göttingen minipig myocardial infarct model

Obesity is a risk factor for the development of coronary artery disease and myocardial infarction (MI). However, most large animal studies of MI are performed in lean animals. Here we assessed the impact of obesity on echocardiographic findings, infarct size, circulating biomarkers, mitochondrial respiratory capacity and mortality in a closed-chest minipig model of MI. The initial study population consisted of 20 obese (median 60.0 kg [interquartile range 55.9-64.6 kg]) and 18 lean (25.0 kg [23.4-36.5 kg]) female Göttingen minipigs. The duration of obesity induction using a western-style diet was up to approximately 6 months (156 days [24-162 days]) before the induction of MI. The induction of MI by 120-min balloon occlusion of the left anterior descending coronary artery was feasible in 17 lean and 17 obese animals. Mortality was higher in obese compared with lean animals (53% versus 12%), driven primarily by refractory ventricular fibrillation during occlusion. Electrocardiographic findings showed longer QRS and QT intervals and more extensive ST-segment elevation in obese animals compared with lean animals during occlusion. Plasma concentrations of pro-atrial natriuretic peptide, pro-C-type natriuretic peptide and cardiac troponin T were significantly lower in obese compared with lean animals. Infarct size estimated 8 weeks after MI was significantly smaller in obese (10% [9-11%]) compared with lean animals (13% [13-15%]). Finally, mitochondrial-complex-I-linked respiratory capacity was overall significantly higher in obese animals; however, no group difference was found in intrinsic mitochondrial respiratory capacity.

Interleukin-6 receptor antibodies (tocilizumab) in acute myocardial infarction with intermediate to high risk of cardiogenic shock development (DOBERMANN-T): study protocol for a double-blinded, placebo-controlled, single-center, randomized clinical trial

BACKGROUND

Inflammation and neurohormonal activation play a significant role in the adverse outcome seen in acute myocardial infarction (AMI) and the development of cardiogenic shock (CS), which is associated with a mortality rate up to 50%. Treatment with anti-inflammatory drugs such as tocilizumab, an interleukin-6 receptor antagonist, has been shown to reduce troponin release and reduce the myocardial infarct size in AMI patients and it may therefore have cardioprotective properties.

METHODS

This is a double-blind, placebo-controlled, single-center randomized clinical trial, including adult AMI patients without CS at hospital arrival, undergoing percutaneous coronary intervention (PCI) within 24 h from symptom onset, and at intermediate to high risk of developing CS (ORBI risk score ≥ 10). A total of 100 participants will be randomized to receive a single intravenous dose of tocilizumab (280 mg) or placebo (normal saline). The primary outcome is peak plasma pro-B-type natriuretic peptide (proBNP) within 48 h, assessed using serial measurements at intervals: before infusion, 12, 24, 36, and 48 h after infusion. Secondary endpoints include the following: (1) cardiac magnetic resonance imaging (CMR) during 24-48 h after admission and at follow-up after 3 months with assessment of left ventricular area at risk, final infarct size, and the derived salvage index and (2) biochemical markers of inflammation (C-reactive protein and leukocyte counts) and cardiac injury (troponin T and creatinine kinase MB).

DISCUSSION

Modulation of interleukin-6-mediated inflammation in patients with AMI, treated with acute PCI, and at intermediate to high risk of in-hospital CS may lead to increased hemodynamic stability and reduced left ventricular infarct size, which will be assessed using blood biomarkers with proBNP as the primary outcome and inflammatory markers, troponin T, and CMR with myocardial salvage index as the secondary endpoints.

TRIAL REGISTRATION

Registered with the Regional Ethics Committee (H-21045751), EudraCT (2021-002028-19), ClinicalTrials.gov (NCT05350592). Study registration date: 2022-03-08, Universal Trial Number U1111-1277-8523.

Cardiomyocyte-derived C-type natriuretic peptide diminishes myocardial ischaemic injury by promoting revascularisation and limiting fibrotic burden

BACKGROUND

C-type natriuretic peptide (CNP) is a significant player in the maintenance of cardiac and vascular homeostasis regulating local blood flow, platelet and leukocyte activation, heart structure and function, angiogenesis and metabolic balance. Since such processes are perturbed in myocardial infarction (MI), we explored the role of cardiomyocyte-derived CNP, and pharmacological administration of the peptide, in offsetting the pathological consequences of MI.

METHODS

Wild type (WT) and cardiomyocyte-restricted CNP null (cmCNP-/-) mice were subjected to left anterior descending coronary artery (LADCA) ligation and acute effects on infarct size and longer-term outcomes of cardiac repair explored. Heart structure and function were assessed by combined echocardiographic and molecular analyses. Pharmacological administration of CNP (0.2 mg/kg/day; s.c.) was utilized to assess therapeutic potential.

RESULTS

Compared to WT littermates, cmCNP-/- mice had a modestly increased infarct size following LADCA ligation but without significant deterioration of cardiac structural and functional indices. However, cmCNP-/- animals exhibited overtly worse heart morphology and contractility 6 weeks following MI, with particularly deleterious reductions in left ventricular ejection fraction, dilatation, fibrosis and revascularization. This phenotype was largely recapitulated in animals with global deletion of natriuretic peptide receptor (NPR)-C (NPR-C-/-). Pharmacological administration of CNP rescued the deleterious pathology in WT and cmCNP-/-, but not NPR-C-/-, animals.

CONCLUSIONS AND IMPLICATIONS

Cardiomyocytes synthesize and release CNP as an intrinsic protective mechanism in response to MI that reduces cardiac structural and functional deficits; these salutary actions are primarily NPR-C-dependent. Pharmacological targeting of CNP may represent a new therapeutic option for MI.

Low-dose dobutamine in acute myocardial infarction with intermediate to high risk of cardiogenic shock development (the DOBERMANN-D trial): study protocol for a double-blinded, placebo-controlled, single-center, randomized clinical trial

BACKGROUND

Cardiogenic shock (CS) occurs in 5-10% of patients with acute myocardial infarction (AMI), and the condition is associated with a 30-day mortality rate of up to 50%. Most of the AMI patients are in SCAI SHOCK stage B upon hospital arrival, but some of these patients will progression through the stages to overt shock (SCAI C-E). Around one third of patients who develop CS are not in shock at the time of hospital admission. Pro-B-type natriuretic peptide (proband) is a biomarker closely related to CS development. The aim of this study is to investigate the potential for preventing progression of hemodynamic instability by early inotropic support with low-dose dobutamine infusion administrated after revascularization in AMI patients with intermediate to high risk of in-hospital CS development.

METHODS

This investigator-initiated, double-blinded, placebo-controlled, randomized, single-center, clinical trial will include 100 AMI patients (≥ 18 years) without CS at hospital admission and at intermediate-high risk of in-hospital CS development (ORBI risk score ≥ 10). Patients will be randomized in a 1:1 ratio to a 24 h intravenous (IV) infusion of dobutamine (5 μg/kg/min) or placebo (NaCl) administrated after acute percutaneous coronary intervention (PCI) (< 24 h from symptom onset). Blood samples are drawn at time points from study inclusion (before infusion, 12, 24, 36, and 48 h). The primary outcome is peak plasma proBNP within 48 h after infusion as a surrogate-measure for the hemodynamic status. Hemodynamic function will be assessed pulse rate, blood pressure, and lactate within 48 h after infusion and by transthoracic echocardiography (TTE) performed after 24-48 h and at follow-up after 3 months. Markers of cardiac injury (troponin T and creatine kinase MB (CK-MB)) will be assessed.

DISCUSSION

Early inotropic support with low-dose dobutamine infusion in patients with AMI, treated with acute PCI, and at intermediate-high risk of in-hospital CS may serve as an intervention promoting hemodynamic stability and facilitating patient recovery. The effect will be assessed using proBNP as a surrogate marker of CS development, hemodynamic measurements, and TTE within the initial 48 h and repeated at a 3-month follow-up.

TRIAL REGISTRATION

The Regional Ethics Committee : H-21045751. EudraCT: 2021-002028-19.

CLINICALTRIALS

gov: NCT05350592, Registration date: 2022-03-08. WHO Universal Trial Number: U1111-1277-8523.

Physiological and Pathophysiological Effects of C-Type Natriuretic Peptide on the Heart

Simple Summary

C-type natriuretic peptide (CNP) is the third member of the natriuretic peptide family. Unlike atrial natriuretic peptide (ANP) and brain natriuretic peptide (BNP), CNP was not previously regarded as an important cardiac modulator. However, recent studies have revealed the physiological and pathophysiological importance of CNP in the heart; in concert with its cognate natriuretic peptide receptor-B (NPR-B), CNP has come to be regarded as the major heart-protective natriuretic peptide in the failed heart. In this review, I introduce the history of research on CNP in the cardiac field.

Abstract

C-type natriuretic peptide (CNP) is the third member of the natriuretic peptide family. Unlike other members, i.e., atrial natriuretic peptide (ANP) and brain natriuretic peptide (BNP), which are cardiac hormones secreted from the atrium and ventricle of the heart, respectively, CNP is regarded as an autocrine/paracrine regulator with broad expression in the body. Because of its low expression levels compared to ANP and BNP, early studies failed to show its existence and role in the heart. However, recent studies have revealed the physiological and pathophysiological importance of CNP in the heart; in concert with the distribution of its specific natriuretic peptide receptor-B (NPR-B), CNP has come to be regarded as the major heart-protective natriuretic peptide in the failed heart. NPR-B generates intracellular cyclic guanosine 3′,5′-monophosphate (cGMP) upon CNP binding, followed by various molecular effects including the activation of cGMP-dependent protein kinases, which generates diverse cytoprotective actions in cardiomyocytes, as well as in cardiac fibroblasts. CNP exerts negative inotropic and positive lusitropic responses in both normal and failing heart models. Furthermore, osteocrin, the intrinsic and specific ligand for the clearance receptor for natriuretic peptides, can augment the effects of CNP and may supply a novel therapeutic strategy for cardiac protection.