Attenuated natriuretic response to adrenomedullin in experimental heart failure

Mid-Regional Proadrenomedullin in COVID-19-May It Act as a Predictor of Prolonged Cardiovascular Complications?

The rising prevalence of cardiovascular disease (CVD) and the impact of the SARS-CoV-2 pandemic have both led to increased mortality rates, affecting public health and the global economy. Therefore, it is essential to find accessible, non-invasive prognostic markers capable of identifying patients at high risk. One encouraging avenue of exploration is the potential of mid-regional proadrenomedullin (MR-proADM) as a biomarker in various health conditions, especially in the context of CVD and COVID-19. MR-proADM presents the ability to predict mortality, heart failure, and adverse outcomes in CVD, offering promise for improved risk assessment and treatment strategies. On the other hand, an elevated MR-proADM level is associated with disease severity and cytokine storms in patients with COVID-19, making it a predictive indicator for intensive care unit admissions and mortality rates. Moreover, MR-proADM may have relevance in long COVID, aiding in the risk assessment, triage, and monitoring of individuals at increased risk of developing prolonged cardiac issues. Our review explores the potential of MR-proADM as a predictor of enduring cardiovascular complications following COVID-19 infection.

Angiotensin receptor neprilysin inhibition compared with enalapril on the risk of clinical progression in surviving patients with heart failure

BACKGROUND

Clinical trials in heart failure have focused on the improvement in symptoms or decreases in the risk of death and other cardiovascular events. Little is known about the effect of drugs on the risk of clinical deterioration in surviving patients.

METHODS AND RESULTS

We compared the angiotensin-neprilysin inhibitor LCZ696 (400 mg daily) with the angiotensin-converting enzyme inhibitor enalapril (20 mg daily) in 8399 patients with heart failure and reduced ejection fraction in a double-blind trial. The analyses focused on prespecified measures of nonfatal clinical deterioration. In comparison with the enalapril group, fewer LCZ696-treated patients required intensification of medical treatment for heart failure (520 versus 604; hazard ratio, 0.84; 95% confidence interval, 0.74-0.94; P=0.003) or an emergency department visit for worsening heart failure (hazard ratio, 0.66; 95% confidence interval, 0.52-0.85; P=0.001). The patients in the LCZ696 group had 23% fewer hospitalizations for worsening heart failure (851 versus 1079; P<0.001) and were less likely to require intensive care (768 versus 879; 18% rate reduction, P=0.005), to receive intravenous positive inotropic agents (31% risk reduction, P<0.001), and to have implantation of a heart failure device or cardiac transplantation (22% risk reduction, P=0.07). The reduction in heart failure hospitalization with LCZ696 was evident within the first 30 days after randomization. Worsening of symptom scores in surviving patients was consistently more common in the enalapril group. LCZ696 led to an early and sustained reduction in biomarkers of myocardial wall stress and injury (N-terminal pro-B-type natriuretic peptide and troponin) versus enalapril.

CONCLUSIONS

Angiotensin-neprilysin inhibition prevents the clinical progression of surviving patients with heart failure more effectively than angiotensin-converting enzyme inhibition.

CLINICAL TRIAL REGISTRATION URL

http://www.clinicaltrials.gov. Unique identifier: NCT01035255.

Ovine models for chronic heart failure

PURPOSE

Testing and optimizing of surgical therapies for chronic heart failure (CHF) requires large animal models. CHF has been induced in several large animal species. Sheep have modest body mass increase and demonstrate docile behavior and are therefore a preferred species in research on surgical therapies for CHF METHODS: A literature search for existing ovine CHF models was performed, using search terms "sheep" and "heart failure". Relevant secondary references were traced.

RESULTS

Rapid ventricular pacing produces rapid-onset CHFE Its severity ranges from moderate left ventricular failure to severe biventricular failure, depending on length and frequency of pacing. Its counterpart in human CHF is tachycardia-induced HF since it is reversible upon cessation of pacing. Myocardial damage models include CHF induced by cardiototoxic drugs and ischemia. Ischemia-based models include coronary microembolization, occlusion and ischemia/reperfusion models. The microembolization model is relevant to diabetic cardiomyopathy. Coronary occlusion models exhibit variable functional impairment, some with aneurysm formation, and some with mitral valve regurgitation, depending on occlusion localization. They are relevant to CHF following non-reperfused myocardial infarction. Coronary occlusion/reperfusion models are relevant to the occurrence of human ãã despite coronary artery recanalization. Pressure overload of left and right ventricle is induced by aortic and pulmonary artery banding, respectively. Hypertrophy precedes CHF as in patients with valve stenosis and hypertension. Volume overload is induced by valve damage or shunt creation. Atrioventricular valve regurgitation is the most important clinical counterpart.

CONCLUSION

Several ovine CHF models exist. Since they exhibit important cardiac pathology differences, the choice of model should be based on the specific experimental question.

Gene expression of adrenomedullin in canine normal tissues and diseased hearts

The purposes of this study were to determine the tissue distribution of canine adrenomedullin (AM) and to determine whether increased canine AM mRNA expression is associated with congestive heart failure (CHF) due to mitral regurgitation (MR). Canine AM mRNA expression was detectable in various normal tissues, including cardiovascular tissues. In addition, the AM mRNA expression in the left atrium of dogs with MR was significantly higher than that in normal subjects. In conclusion, AM is a potential neurohumoral factor in dogs with CHF due to MR.

Diagnostic performance of mid-regional pro-adrenomedullin as an analyte for the exclusion of left ventricular dysfunction

AIMS

In ambulatory patients with coronary artery disease (CAD) we aimed to evaluate the diagnostic performance of mid-regional pro-adrenomedullin (MR-proADM) for the detection or exclusion of impaired left ventricular ejection fraction (LVEF).

METHODS AND RESULTS

MR-proADM levels were measured in blood samples taken from 102 outpatients with CAD classified according to the New York Heart Association (NYHA) and Canadian Cardiovascular society (CCS) I-II. Increased levels of MR-proADM correlated with impaired LVEF (r=-0.21, p=0.046). The optimal threshold of MR-proADM for identification of impaired LVEF <50% was 0.54 nmol/L with an area under the ROC curve (AUC) of 0.64 (p=0.06). In univariate and multivariate calculation, MR-proADM >0.54 nmol/L remained associated with left ventricular dysfunction even after adjusting for age and gender. The negative predictive value (NPV) for MR-proADM <or=0.54 nmol/L was 88%, the specificity was 66%.

CONCLUSIONS

We showed that MR-proADM is related to impaired LVEF. With an NPV of 88% MR-proADM might be a supportive tool to exclude negatively tested outpatients with CAD from further LVEF-diagnosis with moderate reliability.

Distinct roles for renal particulate and soluble guanylyl cyclases in preserving renal function in experimental acute heart failure

Worsening renal function in the setting of human acute heart failure (AHF) predicts poor outcomes, such as rehospitalization and increased mortality. Understanding potential renoprotective mechanisms is warranted. The guanylate cyclase (GC) enzymes and their second messenger cGMP are the target of two important circulating neurohumoral systems with renoprotective properties. Specifically, natriuretic peptides (NP) released from the heart with AHF target particulate GC in the kidney, while the nitric oxide (NO) system is an activator of renal soluble GC. We hypothesized that both systems are essential to preserve renal excretory and hemodynamic function in AHF but with distinct roles. We investigated these roles in three groups of anesthetized dogs (6 each) with AHF induced by rapid ventricular pacing. After a baseline AHF clearance, each group received intrarenal vehicle (control), N(G)-monomethyl-l-arginine (l-NMMA), a competitive NO inhibitor (50 microg.kg(-1).min(-1)) or a specific NP receptor antagonist, HS-142-1 (0.5 mg/kg). We observed that intrarenal l-NMMA decreased renal blood flow (RBF) without significant decreases in glomerular filtration rate (GFR), urinary sodium excretion (UNaV), or urinary cGMP. In contrast, HS-142-1 resulted in a decrease in UNaV and cGMP excretion together with a reduction in GFR and an increase in distal fractional tubular sodium reabsorption. We conclude that in AHF, the NP system plays a role in maintaining sodium excretion and GFR, while the function of NO is in the maintenance of RBF. These studies have both physiological and therapeutic implications warranting further research into cardiorenal interactions in this syndrome of AHF.

Adrenomedullin in heart failure

Patients with heart failure have frequently been reported to show elevated levels of plasma adrenomedullin. These levels generally correlate with severity of hemodynamic dysfunction and also with neurohormonal indices which are activated according to the severity of heart failure. Furthermore, adrenomedullin gene expression in the heart and kidney is increased in experimental and clinical heart failure. A small number of studies have examined the responses to infusion of adrenomedullin in experimental and clinical heart failure. These studies have generally shown that infusion of adrenomedullin has beneficial hemodynamic effects and promotes maintenance or improvement in renal function, although most of these trials were of short duration. The available data suggest that adrenomedullin in the heart, kidney and plasma is increased in heart failure, possibly to counter the activation or actions of vasoconstricting and sodium-retaining hormone systems. An improved understanding of the role of adrenomedullin in heart failure might lead to the development of therapeutic agents acting through adrenomedullin receptors.

An ovine model of tachycardia-induced degenerative dilated cardiomyopathy and heart failure with prolonged onset

BACKGROUND

The aim of this study was to develop a model of long-term progressive heart failure (HF).

METHODS AND RESULTS

A cardiac output flowprobe was implanted on the pulmonary artery of 9 adult sheep weighing 40 to 50 kg. Rapid ventricular pacing for 21 days at 160 to 190 bpm (rate A) resulted in moderate HF. Animals were then paced at 205 to 215 bpm (rate B) for 42 days (severe HF) and for 28 days at rate B (advanced HF). Data were collected at baseline and moderate, severe, and advanced HF during submaximal exercise testing and by transthoracic echocardiography in sinus rhythm. There were marked increases in left ventricular (LV) area, mitral valve regurgitation, and LV end-diastolic pressure and decreases in LV wall thickness, LV ejection fraction, positive and negative dP/dt(max), and positive (dP/dt(max))/P throughout the pacing protocol.

CONCLUSIONS

This ovine HF model incorporates the progressive nature of human HF and allows examination of both structural changes and hemodynamic parameters of HF during and after exercise challenge.