Prognostic value of secretoneurin in chronic heart failure. Data from the GISSI-Heart Failure trial.

BACKGROUND: Circulating secretoneurin (SN) concentrations have been found to provide prognostic information in patients with acute heart failure. We wanted to assess whether SN would improve prognostication also in patients with chronic heart failure (HF) in a large multicenter trial. METHODS: We measured plasma SN concentrations at randomization (n = 1224) and after 3 months (n = 1103) in patients with chronic, stable HF from the GISSI-HF study. The co-primary endpoints were (1) time to death or (2) admission to hospital for cardiovascular reasons. RESULTS: Mean age was 67 years and 80% were male. Median (quartile 1-3) SN concentrations were 42.6 (35.0-62.8) pmol/L on randomization and 42.0 (34.5-53.1) pmol/L after 3 months, which are higher than SN concentrations in healthy subjects. Higher SN concentrations at randomization were associated with lower body-mass index (BMI), lower systolic blood pressure, lower estimated glomerular filtration rate (eGFR), higher B-type natriuretic peptide (BNP) concentrations, and diagnosis of chronic obstructive pulmonary disease. During median follow-up of 3.9 years, 344 patients (27.0%) died. After adjusting for age, sex, left ventricular ejection fraction, BMI, functional class, ischemic etiology, heart rate, blood pressure, eGFR, bilirubin, comorbidities, and BNP concentrations, logarithmically transformed SN concentrations on randomization were associated with mortality (HR 2.60 (95% CI 1.01-6.70), p = 0.047). SN concentrations were also associated with admission to hospital for cardiovascular reasons, but the association was attenuated and no longer significant in multivariable analysis. CONCLUSION: Plasma SN concentrations provided incremental prognostic information to established risk indices and biomarkers in a large cohort of chronic HF patients.

Glycosylated Chromogranin A in Heart Failure: Implications for Processing and Cardiomyocyte Calcium Homeostasis.

BACKGROUND: Chromogranin A (CgA) levels have previously been found to predict mortality in heart failure (HF), but currently no information is available regarding CgA processing in HF and whether the CgA fragment catestatin (CST) may directly influence cardiomyocyte function. METHODS AND RESULTS: CgA processing was characterized in postinfarction HF mice and in patients with acute HF, and the functional role of CST was explored in experimental models. Myocardial biopsies from HF, but not sham-operated mice, demonstrated high molecular weight CgA bands. Deglycosylation treatment attenuated high molecular weight bands, induced a mobility shift, and increased shorter CgA fragments. Adjusting for established risk indices and biomarkers, circulating CgA levels were found to be associated with mortality in patients with acute HF, but not in patients with acute exacerbation of chronic obstructive pulmonary disease. Low CgA-to-CST conversion was also associated with increased mortality in acute HF, thus, supporting functional relevance of impaired CgA processing in cardiovascular disease. CST was identified as a direct inhibitor of CaMKIIδ (Ca2+/calmodulin-dependent protein kinase IIδ) activity, and CST reduced CaMKIIδ-dependent phosphorylation of phospholamban and the ryanodine receptor 2. In line with CaMKIIδ inhibition, CST reduced Ca2+ spark and wave frequency, reduced Ca2+ spark dimensions, increased sarcoplasmic reticulum Ca2+ content, and augmented the magnitude and kinetics of cardiomyocyte Ca2+ transients and contractions. CONCLUSIONS: CgA-to-CST conversion in HF is impaired because of hyperglycosylation, which is associated with clinical outcomes in acute HF. The mechanism for increased mortality may be dysregulated cardiomyocyte Ca2+ handling because of reduced CaMKIIδ inhibition.

Secretoneurin is a novel prognostic cardiovascular biomarker associated with cardiomyocyte calcium handling.

BACKGROUND: Secretoneurin (SN) levels are increased in patients with heart failure (HF), but whether SN provides prognostic information and influences cardiomyocyte function is unknown. OBJECTIVES: This study sought to evaluate the merit of SN as a cardiovascular biomarker and assess effects of SN on cardiomyocyte Ca(2+) handling. METHODS: We assessed the association between circulating SN levels and mortality in 2 patient cohorts and the functional properties of SN in experimental models. RESULTS: In 143 patients hospitalized for acute HF, SN levels were closely associated with mortality (n = 66) during follow-up (median 776 days; hazard ratio [lnSN]: 4.63; 95% confidence interval: 1.93 to 11.11; p = 0.001 in multivariate analysis). SN reclassified patients to their correct risk strata on top of other predictors of mortality. In 155 patients with ventricular arrhythmia-induced cardiac arrest, SN levels were also associated with short-term mortality (n = 51; hazard ratio [lnSN]: 3.33; 95% confidence interval: 1.83 to 6.05; p < 0.001 in multivariate analysis). Perfusing hearts with SN yielded markedly increased myocardial levels and SN internalized into cardiomyocytes by endocytosis. Intracellularly, SN reduced Ca(2+)/calmodulin (CaM)-dependent protein kinase II δ (CaMKIIδ) activity via direct SN-CaM and SN-CaMKII binding and attenuated CaMKIIδ-dependent phosphorylation of the ryanodine receptor. SN also reduced sarcoplasmic reticulum Ca(2+) leak, augmented sarcoplasmic reticulum Ca(2+) content, increased the magnitude and kinetics of cardiomyocyte Ca(2+) transients and contractions, and attenuated Ca(2+) sparks and waves in HF cardiomyocytes. CONCLUSIONS: SN provided incremental prognostic information to established risk indices in acute HF and ventricular arrhythmia-induced cardiac arrest.

Secretogranin II; a protein increased in the myocardium and circulation in heart failure with cardioprotective properties.

BACKGROUND: Several beneficial effects have been demonstrated for secretogranin II (SgII) in non-cardiac tissue. As cardiac production of chromogranin A and B, two related proteins, is increased in heart failure (HF), we hypothesized that SgII could play a role in cardiovascular pathophysiology. METHODOLOGY/PRINCIPAL FINDINGS: SgII production was characterized in a post-myocardial infarction heart failure (HF) mouse model, functional properties explored in experimental models, and circulating levels measured in mice and patients with stable HF of moderate severity. SgII mRNA levels were 10.5 fold upregulated in the left ventricle (LV) of animals with myocardial infarction and HF (p<0.001 vs. sham-operated animals). SgII protein levels were also increased in the LV, but not in other organs investigated. SgII was produced in several cell types in the myocardium and cardiomyocyte synthesis of SgII was potently induced by transforming growth factor-ß and norepinephrine stimulation in vitro. Processing of SgII to shorter peptides was enhanced in the failing myocardium due to increased levels of the proteases PC1/3 and PC2 and circulating SgII levels were increased in mice with HF. Examining a pathophysiological role of SgII in the initial phase of post-infarction HF, the SgII fragment secretoneurin reduced myocardial ischemia-reperfusion injury and cardiomyocyte apoptosis by 30% and rapidly increased cardiomyocyte Erk1/2 and Stat3 phosphorylation. SgII levels were also higher in patients with stable, chronic HF compared to age- and gender-matched control subjects: median 0.16 (Q1-3 0.14-0.18) vs. 0.12 (0.10-0.14) nmol/L, p<0.001. CONCLUSIONS: We demonstrate increased myocardial SgII production and processing in the LV in animals with myocardial infarction and HF, which could be beneficial as the SgII fragment secretoneurin protects from ischemia-reperfusion injury and cardiomyocyte apoptosis. Circulating SgII levels are also increased in patients with chronic, stable HF and may represent a new cardiac biomarker.