Biological variation of secretoneurin; a novel cardiovascular biomarker implicated in arrhythmogenesis

Background Secretoneurin is a novel prognostic biomarker that may predict mortality in heart failure and the occurrence of ventricular arrhythmias. This study reports the within subject variation (CVI), between subject variation (CVG), reference change values (RCV) and index of individuality (II) of secretoneurin. Methods Thirty healthy volunteers were included. Non-fasting samples were obtained between 8 and 10 am once a week for ten weeks. Secretoneurin was analyzed in duplicate using ELISA. No outliers were present according to Burnett and Reeds‘ criteria. Simple linear regression did not identify significant trends. Variance homogeneity in the analytical variance and CVI were tested using Cochrane’s and Bartlett’s tests and four participants were excluded. Calculation of CVI, CVG and RCV were done on ln transformed data as described by Fokkema, the II was calculated using retransformed data. Results The median age of the participants was 36 years and 53% were female. Non-fasting glucose, eGFR(CKD-EPI), cTnT and NT-proBNP concentrations were within the normal range. Median secretoneurin concentrations were 38 pmol/L (women) and 33 pmol/L (men), p-value < 0.001. CVI and CVG were 9.8% (CI 8.7% to 11.0%) and 20.0 (CI 15.4% to 28.0%), respectively. RCV were 38.7% (CI 35.5% to 42.7%) and −27.9 (CI −29.9 to −26.2) and the II were 0.60 (CI 0.42–0.78). No gender differences were present. Conclusion Secretoneurin has a fairly low CVI, CVG, RCV and II, indicating that it could be suitable as a diagnostic or prognostic biomarker and that delta values in serial samplings may be preferable for identifying clinical changes.publishedVersio

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&lt;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-beta 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&lt;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

Glycosylated Chromogranin A: Potential Role in the Pathogenesis of Heart Failure

Purpose of Review Endocrine and paracrine factors influence the cardiovascular system and the heart by a number of different mechanisms. The chromogranin-secretogranin (granin) proteins seem to represent a new family of proteins that exerts both direct and indirect effects on cardiac and vascular functions. The granin proteins are produced in multiple tissues, including cardiac cells, and circulating granin protein concentrations provide incremental prognostic information to established risk indices in patients with myocardial dysfunction. In this review, we provide recent data for the granin proteins in relation with cardiovascular disease, and with a special focus on chromogranin A and heart failure. Recent Findings Chromogranin A is the most studied member of the granin protein family, and shorter, functionally active peptide fragments of chromogranin A exert protective effects on myocardial cell death, ischemia-reperfusion injury, and cardiomyocyte Ca2+ handling. Granin peptides have also been found to induce angiogenesis and vasculogenesis. Protein glycosylation is an important post-translational regulatory mechanism, and we recently found chromogranin A molecules to be hyperglycosylated in the failing myocardium. Chromogranin A hyperglycosylation impaired processing of full-length chromogranin A molecules into physiologically active chromogranin A peptides, and patients with acute heart failure and low rate of chromogranin A processing had increased mortality compared to other acute heart failure patients. Other studies have also demonstrated that circulating granin protein concentrations increase in parallel with heart failure disease stage. Summary The granin protein family seems to influence heart failure pathophysiology, and chromogranin A hyperglycosylation could directly be implicated in heart failure disease progression. This is a post-peer-review, pre-copyedit version of an article published in Current Heart Failure Reports. The final authenticated version is available online at: http://dx.doi.org/10.1007/s11897-017-0360-

Biological variation of secretoneurin; a novel cardiovascular biomarker implicated in arrhythmogenesis

Background Secretoneurin is a novel prognostic biomarker that may predict mortality in heart failure and the occurrence of ventricular arrhythmias. This study reports the within subject variation (CVI), between subject variation (CVG), reference change values (RCV) and index of individuality (II) of secretoneurin. Methods Thirty healthy volunteers were included. Non-fasting samples were obtained between 8 and 10 am once a week for ten weeks. Secretoneurin was analyzed in duplicate using ELISA. No outliers were present according to Burnett and Reeds‘ criteria. Simple linear regression did not identify significant trends. Variance homogeneity in the analytical variance and CVI were tested using Cochrane’s and Bartlett’s tests and four participants were excluded. Calculation of CVI, CVG and RCV were done on ln transformed data as described by Fokkema, the II was calculated using retransformed data. Results The median age of the participants was 36 years and 53% were female. Non-fasting glucose, eGFR(CKD-EPI), cTnT and NT-proBNP concentrations were within the normal range. Median secretoneurin concentrations were 38 pmol/L (women) and 33 pmol/L (men), p-value < 0.001. CVI and CVG were 9.8% (CI 8.7% to 11.0%) and 20.0 (CI 15.4% to 28.0%), respectively. RCV were 38.7% (CI 35.5% to 42.7%) and −27.9 (CI −29.9 to −26.2) and the II were 0.60 (CI 0.42–0.78). No gender differences were present. Conclusion Secretoneurin has a fairly low CVI, CVG, RCV and II, indicating that it could be suitable as a diagnostic or prognostic biomarker and that delta values in serial samplings may be preferable for identifying clinical changes

Glycosyalted chromogranin A in heart faiure. 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

SgII production outside of the left ventricle in heart failure.

<p>SgII levels were decreased in pulmonary tissue during HF development, while levels were unchanged in the other tissues examined. SgII levels in the (A) right ventricle, (B) pulmonary tissue, (C) liver, (D) spleen, (E) kidney, (F) stomach, (G) colon, and (H) skeletal muscle were measured by RIA and are presented as fold change ± SEM (n = 6 for both groups, except pulmonary tissue: HF: n = 14, sham: n = 13). # p<0.05.</p

Descriptive statistics of animals.

<p>LV indicates left ventricle; RV, right ventricle; CgA, chromogranin A; CgB, chromogranin B; BNP, B-type natriuretic peptide; IVSd, intraventricular septum thickness in diastole; IVSs, intraventricular septum thickness in systole; LVDd, LV diameter in diastole; LVDs, LV diameter in systole; LVFS, LV fractional shortening; PWd, posterior wall thickness in diastole; PWs, posterior wall thickness in systole; and LAD, left atrial diameter.</p><p>mRNA levels were investigated in a subset of animals (n = 9 HF, n = 8 sham) and are presented as fold change±SEM. Echocardiographic data are reported as mean±SEM and are obtained from a representative subset of animals (13 HF animals, 6 sham animals).</p

Circulating SgII levels are elevated in patients with chronic, stable HF.

<p>SgII levels were significantly increased in HF patients (n = 58) compared to healthy age- and gender-matched control subjects (n = 20): Median 0.16 (Q1–3 0.14–0.18) vs. 0.12 (0.10–0.14) nmol/L, p<0.001. HF patients are presented according to NYHA functional class. The horizontal line within the box represents the median level, the boundaries of the box the 25^th and 75^th percentile levels, and the whiskers the 10^th–90^th percentile. **p<0.001.</p

Descriptive statistics of heart failure patients and control subjects.

<p>NYHA class indicates New York Heart Association functional class; Q1–3, quartile 1–3; LVEF, left ventricular ejection fraction; ACEI, angiotensin converting enzyme inhibitor; ARB, angiotensin II receptor blocker; ASA, acetyl salicylic acid; PPI, proton pump inhibitor; CRT, cardiac resynchronization therapy; ICD, implantable cardioverter-defibrillator; CgA, chromogranin A; CgB, chromogranin B; and BNP, B-type natriuretic peptide. Biomarker levels are presented as median (quartile 1–3).</p

Regulation of cardiomyocyte SgII expression by important hormonal and paracrine factors in HF.

<p>SgII mRNA levels were measured by RT-qPCR after stimulating neonatal rat cardiomyocytes for 24 h with either PBS (Ctr, n = 9), forskolin (FSK n = 5), norepinephrine (NE, n = 5), angiotensin II (AngII, n = 4), endothelin-1 (ET-1, n = 5), transforming growth factor-β (TGF-β, n = 6), or tumor necrosis factor-α (TNF-α, n = 6). SgII mRNA levels are presented as fold change ± SEM vs. PBS-stimulated cells. **p<0.001, *p<0.01, # p<0.05.</p