The role of natriuretic peptides in heart failure

Myokine Musclin Is Critical for Exercise-Induced Cardiac Conditioning

This study investigates the role and mechanisms by which the myokine musclin promotes exercise-induced cardiac conditioning. Exercise is one of the most powerful triggers of cardiac conditioning with proven benefits for healthy and diseased hearts. There is an emerging understanding that muscles produce and secrete myokines, which mediate local and systemic "crosstalk" to promote exercise tolerance and overall health, including cardiac conditioning. The myokine musclin, highly conserved across animal species, has been shown to be upregulated in response to physical activity. However, musclin effects on exercise-induced cardiac conditioning are not established. Following completion of a treadmill exercise protocol, wild type (WT) mice and mice with disruption of the musclin-encoding gene, Ostn, had their hearts extracted and exposed to an ex vivo ischemia-reperfusion protocol or biochemical studies. Disruption of musclin signaling abolished the ability of exercise to mitigate cardiac ischemic injury. This impaired cardioprotection was associated with reduced mitochondrial content and function linked to blunted cyclic guanosine monophosphate (cGMP) signaling. Genetic deletion of musclin reduced the nuclear abundance of protein kinase G (PKGI) and cyclic adenosine monophosphate (cAMP) response element binding (CREB), resulting in suppression of the master regulator of mitochondrial biogenesis, peroxisome proliferator-activated receptor γ coactivator 1α (PGC1α), and its downstream targets in response to physical activity. Synthetic musclin peptide pharmacokinetic parameters were defined and used to calculate the infusion rate necessary to maintain its plasma level comparable to that observed after exercise. This infusion was found to reproduce the cardioprotective benefits of exercise in sedentary WT and Ostn-KO mice. Musclin is essential for exercise-induced cardiac protection. Boosting musclin signaling might serve as a novel therapeutic strategy for cardioprotection.

Cardiac troponin T and NT-proBNP as diagnostic and prognostic biomarkers of primary cardiac involvement and disease severity in systemic sclerosis: A prospective study

OBJECTIVES

The aim of our study was to define the role of high-sensitive cardiac troponin T (hs-cTnT) and NT-proBNP in identifying Systemic Sclerosis (SSc) patients with cardiac involvement and at higher risk of cardiac death.

METHODS

Plasma hs-cTnT and NT-proBNP concentrations were measured in 245 SSc-patients.

RESULTS

hs-cTnT and NT-proBNP levels were higher in SSc-patients than in healthy controls. Hs-cTnT levels were higher than 0.014 ng/ml in 32.3% SSc-patients, while NT-proBNP was above 125 pg/ml in 31.8% of them, irrespective of classical cardiovascular risk factor and of pulmonary arterial hypertension. Elevated hs-cTnT and NT-proBNP were associated with diffuse skin involvement and directly correlated with the skin score. Patients with increased cardiac markers presented a lower left-ventricular ejection fraction (LVEF) and a higher rate of right bundle branch block (RBBB) on electrocardiogram (ECG) compared to patients with normal cardiac enzymes. During the follow-up, 12 SSc-patients experience a disease-related death; 9 of these were directly related to cardiac involvement (sudden cardiac death or heart failure) and the majority of them occurred among patients with increase of at least one cardiac biomarker. Long-term survival was worse in patients with increase of both cardiac biomarkers.

CONCLUSIONS

Evaluation of hs-cTnT and NT-proBNP levels may provide a tool to screen non-invasively SSc-patients for heart involvement. A higher incidence of impaired systolic function, ECG abnormalities and a poor outcome in SSc-patients with elevated cardiac enzymes suggests that they may be valuable screening biomarkers to detect a cardiac damage at early stages and to improve risk stratification.

A Review of New Pharmacologic Treatments for Patients With Chronic Heart Failure With Reduced Ejection Fraction

Heart failure (HF) impacts an estimated 5.7 million Americans, and its prevalence is projected to increase to more than 8 million Americans in the next 15 years. Key clinical trials have established an evidence-based foundation for treatment of heart failure with reduced ejection fraction (HFrEF). Ivabradine and sacubitril/valsartan, which inhibit the f-channel and the angiotensin receptor and neprilysin, respectively, were recently approved by the Food and Drug Administration for HFrEF. In systolic heart failure, treatment with the If inhibitor ivabradine significantly reduced the combined endpoint of cardiovascular mortality or heart failure hospital admission vs placebo (P < .05). In the Prospective Comparison of angiotensin receptor-neprilysin inhibitor (ARNI) with angiotensin-converting enzyme inhibitor (ACEI) to Determine Impact on Global Mortality and Morbidity in Heart Failure trial, sacubitril/valsartan significantly reduced the combined endpoint of cardiovascular death or heart failure hospitalization vs enalapril (P < .001). The place of therapy with ivabradine and sacubitril/valsartan is defined by these trials and their interplay with guideline-directed medical therapy. Ivabradine and sacubitril/valsartan increase pharmacotherapy options for the treatment of HFrEF but are not yet first-line agents. Clinical application will be better defined in the coming years as practitioners increase their familiarity with ivabradine and sacubitril/valsartan.

Elevation of B-type natriuretic peptide is a sensitive marker of left ventricular diastolic dysfunction in patients with maintenance haemodialysis

OBJECTIVE

To determine the clinical value of B-type natriuretic peptide (BNP) in diagnosing left ventricular diastolic dysfunction (LVDD) associated with maintenance haemodialysis (MHD) population.

METHODS

Plasma BNP was determined in 59 MHD patients with normal ejection fraction. The ratio of early to late annular velocity (E'/A') was determined by tissue Doppler imaging as a parameter of diastolic function.

RESULTS

LVDD occurred in 66% of the patients. Receiver-operating characteristic curve analyses identified a cut-off of 353.6 pg ml(-1) as the one with the highest sensitivity and specificity for detecting LVDD.

CONCLUSIONS

Plasma BNP may serve as a potential biomarker in diagnosing LVDD in MHD patients with normal systolic function.