Biomarker Phenotypes in Heart Failure with Preserved Ejection Fraction Using Hierarchical Clustering-A Pilot Study.

OBJECTIVES: We hypothesized the existence of distinct phenotype-based groups within the very heterogeneous population of patients of heart failure with preserved ejection fraction (HFpEF) and using an unsupervised hierarchical clustering applied to plasma concentration of various biomarkers. We sought to characterize them as "biomarker phenotypes" and to conclude differences in their overall characteristics. SUBJECTS AND METHODS: A cross-sectional study was conducted on 75 patients with HFpEF. An agglomerative hierarchical clustering was performed using the concentrations of cardiac remodeling biomarkers, BNP and cystatin C. RESULTS: According to the obtained heat map of this analysis, we concluded two distinctive biomarker phenotypes within the HFpEF. The "remodeled phenotype" presented with significantly higher concentrations of cardiac remodeling biomarkers and cystatin C (p < 0.001), higher prevalence of myocardial infarction (p = 0.047), STEMI (p = 0.045), atrial fibrillation (p = 0.047) and anemia: lower erythrocytes count (p=0.037), hemoglobin concentration (p = 0.034) and hematocrit (p = 0.046), compared to "non-remodeled phenotype". Echocardiography showed that patients within "remodeled phenotype" had significantly increased parameters of left ventricular remodeling: left ventricular mass index (p < 0.001), left ventricular mass (p = 0.001), diameters of the interventricular septum (p = 0.027) and posterior wall (p = 0.003) and function alterations, intermediate pauses duration >2.0 seconds (p < 0.006). CONCLUSION: Unsupervised hierarchical clustering applied to plasma concentration of various biomarkers in patients with HFpEF enables the identification of two biomarker phenotypes, significantly different in clinical characteristics and cardiac structure and function, whereas one phenotype particularly relates to patients with reduced ejection fraction. These findings imply distinct underlying pathophysiology within a unique cohort of HFpEF.

The Scientific Rationale for the Introduction of Renalase in the Concept of Cardiac Fibrosis.

Cardiac fibrosis represents a redundant accumulation of extracellular matrix proteins, resulting from a cascade of pathophysiological events involved in an ineffective healing response, that eventually leads to heart failure. The pathophysiology of cardiac fibrosis involves various cellular effectors (neutrophils, macrophages, cardiomyocytes, fibroblasts), up-regulation of profibrotic mediators (cytokines, chemokines, and growth factors), and processes where epithelial and endothelial cells undergo mesenchymal transition. Activated fibroblasts and myofibroblasts are the central cellular effectors in cardiac fibrosis, serving as the main source of matrix proteins. The most effective anti-fibrotic strategy will have to incorporate the specific targeting of the diverse cells, pathways, and their cross-talk in the pathogenesis of cardiac fibroproliferation. Additionally, renalase, a novel protein secreted by the kidneys, is identified. Evidence demonstrates its cytoprotective properties, establishing it as a survival element in various organ injuries (heart, kidney, liver, intestines), and as a significant anti-fibrotic factor, owing to its, in vitro and in vivo demonstrated pleiotropy to alleviate inflammation, oxidative stress, apoptosis, necrosis, and fibrotic responses. Effective anti-fibrotic therapy may seek to exploit renalase's compound effects such as: lessening of the inflammatory cell infiltrate (neutrophils and macrophages), and macrophage polarization (M1 to M2), a decrease in the proinflammatory cytokines/chemokines/reactive species/growth factor release (TNF-α, IL-6, MCP-1, MIP-2, ROS, TGF-ß1), an increase in anti-apoptotic factors (Bcl2), and prevention of caspase activation, inflammasome silencing, sirtuins (1 and 3) activation, and mitochondrial protection, suppression of epithelial to mesenchymal transition, a decrease in the pro-fibrotic markers expression ('α-SMA, collagen I, and III, TIMP-1, and fibronectin), and interference with MAPKs signaling network, most likely as a coordinator of pro-fibrotic signals. This review provides the scientific rationale for renalase's scrutiny regarding cardiac fibrosis, and there is great anticipation that these newly identified pathways are set to progress one step further. Although substantial progress has been made, indicating renalase's therapeutic promise, more profound experimental work is required to resolve the accurate underlying mechanisms of renalase, concerning cardiac fibrosis, before any potential translation to clinical investigation.

The Discriminatory Ability of Renalase and Biomarkers of Cardiac Remodeling for the Prediction of Ischemia in Chronic Heart Failure Patients With the Regard to the Ejection Fraction.

Background: Renalase has been implicated in chronic heart failure (CHF); however, nothing is known about renalase discriminatory ability and prognostic evaluation. The aims of the study were to assess whether plasma renalase may be validated as a predictor of ischemia in CHF patients stratified to the left ventricular ejection fraction (LVEF) and to determine its discriminatory ability coupled with biomarkers representing a range of heart failure (HF) pathophysiology: brain natriuretic peptide (BNP), soluble suppressor of tumorigenicity (sST2), galectin-3, growth differentiation factor 15 (GDF-15), syndecan-1, and cystatin C. Methods: A total of 77 CHF patients were stratified according to the LVEF and were subjected to exercise stress testing. Receiver operating characteristic curves were constructed, and the areas under curves (AUC) were determined, whereas the calibration was evaluated using the Hosmer-Lemeshow statistic. A DeLong test was performed to compare the AUCs of biomarkers. Results: Independent predictors for ischemia in the total HF cohort were increased plasma concentrations: BNP (p = 0.008), renalase (p = 0.012), sST2 (p = 0.020), galectin-3 (p = 0.018), GDF-15 (p = 0.034), and syndecan-1 (p = 0.024), whereas after adjustments, only BNP (p = 0.010) demonstrated predictive power. In patients with LVEF <45% (HFrEF), independent predictors of ischemia were BNP (p = 0.001), renalase (p < 0.001), sST2 (p = 0.004), galectin-3 (p = 0.003), GDF-15 (p = 0.001), and syndecan-1 (p < 0.001). The AUC of BNP (0.837) was statistically higher compared to those of sST2 (DeLong test: p = 0.042), syndecan-1 (DeLong: p = 0.022), and cystatin C (DeLong: p = 0.022). The AUCs of renalase (0.753), galectin-3 (0.726), and GDF-15 (0.735) were similar and were non-inferior compared to BNP, regarding ischemia prediction. In HFrEF patients, the AUC of BNP (0.980) was statistically higher compared to those of renalase (DeLong: p < 0.001), sST2 (DeLong: p < 0.004), galectin-3 (DeLong: p < 0.001), GDF-15 (DeLong: p = 0.001), syndecan-1 (DeLong: p = 0.009), and cystatin C (DeLong: p = 0.001). The AUC of renalase (0.814) was statistically higher compared to those of galectin-3 (DeLong: p = 0.014) and GDF-15 (DeLong: p = 0.046) and similar to that of sST2. No significant results were obtained in the patients with LVEF >45%. Conclusion: Plasma renalase concentration provided significant discrimination for the prediction of ischemia in patients with CHF and appeared to have similar discriminatory potential to that of BNP. Although further confirmatory studies are warranted, renalase seems to be a relevant biomarker for ischemia prediction, implying its potential contribution to ischemia-risk stratification.

Cardiac Remodeling Biomarkers as Potential Circulating Markers of Left Ventricular Hypertrophy in Heart Failure with Preserved Ejection Fraction.

Soluble suppressor of tumorigenicity 2 (sST2), galectin-3, growth differentiation factor (GDF)-15 and syndecan-1 represent biomarkers of cardiac remodeling, involved in heart failure (HF) progression. We hypothesize that their plasma concentrations, together with brain natriuretic peptide (BNP), are different in HF stratified by ejection fraction (EF), demonstrating correlations with echocardiographic parameters that indicate left ventricular (LV) hypertrophy; LV mass index (LVMI) and posterior wall and septum diameters. HF patients (n = 77) were classified according to EF: reduced EF < 40% (HFrEF), mid-range EF = 40-49% (HFmrEF), preserved EF > 50% (HFpEF). We found that plasma concentrations of four cardiac remodeling biomarkers were highest in HFrEF and lowest in HFpEF, p < 0.001. In HFpEF, remodeling biomarkers independently correlated with LVMI: sST2 (p = 0. 002), galectin-3 (p < 0.001), GDF-15 (p = 0.011), and syndecan-1 (p = 0.006), whereas galectin-3 correlated after multivariable adjustments (p = 0.001). Independent correlates of septum and posterior wall diameters, in HFpEF, were sST2 (p = 0.019; p = 0.026), galectin-3 (p = 0.011; p = 0.009), GDF-15 (p = 0.007; p = 0.001), and syndecan-1 (p = 0.005; p = 0.002). In HFrEF, only sST2, adjusted, correlated with LVMI (p = 0.010), whereas BNP correlated with LVMI (p = 0.002) and EF (p = 0.001). GDF-15 correlated with diastolic dysfunction in HFpEF (p = 0.046) and HFrEF (p = 0.024). Cardiac remodeling biomarkers are potential circulating indicators of LV hypertrophy in HFpEF, which may ensure timely recognition of disease progression among high-risk patients.

The partnership between renalase and ejection fraction as a risk factor for increased cardiac remodeling biomarkers in chronic heart failure patients.

Objective: Heart failure (HF) represents a huge socio-economic burden. It has been demonstrated, experimentally, that renalase, a newly discovered protein, prevents cardiac hypertrophy and adverse remodeling, which is seen in HF. We postulated the following aims: to investigate associations of renalase with biomarkers of cardiac remodeling: galectin-3, soluble suppression of tumorigenicity, (sST2), growth differentiation factor 15 (GDF-15) and syndecan-1, myocardial stretch (BNP) and cardio-renal axis (cystatin C) in HF patients with reduced ejection fraction (HFrEF) and preserved ejection fraction (HFpEF) to determine whether renalase, in combination with left ventricular ejection fraction (LVEF), represents a risk factor for plasma elevation in biomarkers.Methods: We classified HF patients (n = 76) according to LVEF (preserved/reduced), applied a median plasma renalase (113 ng/mL) as a cut-off value (low/high) and created four subgroups of HF patients: HFpEF/low renalase (n = 19), HFrEF/low renalase (n = 19), HFrEF/high renalase (n = 32) and HFpEF/high renalase (n = 6). A control group (n = 35) consisted of healthy volunteers.Results: Plasma concentrations of evaluated biomarkers were determined using an ELISA technique and were highest in HF patients with reduced EF (p < .001, respectively), and renalase's positive correlations were obtained relating to all biomarkers: galectin-3 (r = 0.913; p < .001), sST2 (r = 0.965; p < .001), GDF-15 (r = 0.887; p < .001), syndecan-1 (r = 0.922; p < .001), BNP (r = 0.527; p < .001) and cystatin C (r = 0.844; p < .001) and strong and negative correlation with LVEF (r = -0.456, p < .001). Increased renalase, regardless of the EF (preserved/reduced), was shown to be an independent risk factor for an increase in all evaluated cardiac remodeling biomarkers, p < .001, respectively. However, increased renalase and reduced EF was the only independent risk factor for BNP and cystatin C elevation, p < .001, respectively. Results after multivariable adjustments (age/gender) were identical.Conclusion: When elevated plasma renalase and HF are present, regardless of EF being reduced or preserved, that represents a significant risk factor for increase in cardiac remodeling biomarker plasma concentrations. However, only elevated renalase and reduced EF demonstrated significance as a risk factor for BNP and cystatin C plasma elevation. Renalase may be considered a promising molecule for the improved predictive abilities of conventional biomarkers and is worthy of further investigation.

Association of Plasma Renalase and Left Ventricle Mass Index in Heart Failure Patients Stratified to the Category of the Ejection Fraction: A Pilot Study.

Heart failure represents a growing health problem, with increasing morbidity and mortality globally. According to the mechanisms involved in the pathogenesis of heart failure, many biomarkers have been proposed for the timely diagnosis and prognostication of patients with heart failure, but other than natriuretic peptides, none of them has gained enough clinical significance. Renalase, a new protein derived from kidneys was demonstrated to metabolize catecholamines and to have a cardioprotective role. The aim of the study was to determine whether renalase and brain natriuretic peptide (BNP) concentration could be used to differentiate heart failure patients stratified to the category of the ejection fraction and whether plasma renalase could be used as a biomarker for left ventricle hypertrophy in all subgroups of heart failure patients. We included patients diagnosed with heart failure and stratified them to the three subgroups according to the ejection fraction. Regarding echocardiographic parameters, HFmrEF had an intermediate profile in between HFrEF and HFpEF, with statistical significance in most evaluated parameters. BNP concentration was significantly different in all three subgroups (p < 0.001), and renalase was statistically higher in HFrEF (p = 0.007) compared to the HFmrEF and HFpEF, where its results were similar, without statistical significance. Renalase plasma concentration was demonstrated to be highly and positively associated with left ventricle mass index in HFrEF (p = 0.029), as well as increased plasma concentration of BNP (p = 0.006). In the HFmrEF group of patients, body mass index was positively associated with LVMI (p = 0.05), while in the patients with HFpEF, diabetes mellitus was demonstrated to have a positive association with LVMI (p = 0.043). These findings suggest that renalase concentration may be measured in order to differentiate patients with reduced ejection fraction. Plasma renalase concentrations positively correlated with left ventricle hypertrophy in patients with reduced ejection fraction, being strongly associated with increased left ventricular mass index.