Plasma Levels of Apelinergic System Components in Patients with Chronic and Acute Coronary Syndromes-A Pilot Study

Apelinergic System in the Left Ventricle Adverse Remodeling After Myocardial Infarction: A Preliminary Study

Background

Despite a growing evidence from the animal models of the cardioprotective function of the apelinergic system in the setting of myocardial infarction, little is known on the role of apelinergic system in the development of post- infarction adverse left ventricle remodeling in humans.

Methods

The study group consisted of 49 patients with first-time ST-segment elevation myocardial infarction of anterior wall treated invasively. Echocardiography was performed on index hospitalization and on one-year check-up, with categorizing the study population into group with adverse LV remodeling defined as an increase of LV end diastolic volume by >20% (n = 12) and the group without adverse remodeling (n = 29). ELA, AP-17, AP-13 and APJ receptor levels were measured on one-year follow-up.

Results

Patients with adverse LV remodeling presented significantly higher plasma level of apelin-13 (85.63 [75.43-96.13] vs 65.43 [57.35-69.35], p = 0.001) and apelin-17 (69.36 [42.61-77.04] vs 30.04 [25.97-41.95], p = 0.004). In a univariable logistic regression analysis, higher LVEDV and LVEDV1, higher LVESV and LVESVi, lower LVEF, higher WMSI score, higher SYNTAX score, higher levels of hs-CRP during index hospitalization and higher levels of AP-13 and AP-17 on the one-year check-up were associated with adverse LV remodeling. In multivariable logistic regression analysis, only AP-17 level was independently associated with adverse LV remodeling (p = 0.050).

Conclusion

Apelinergic system may be involved in the development of post- infarction adverse left ventricle remodeling.

Assessment of Levels of Apelinergic System Peptides in Serum and Epicardial Adipose Tissue in Patients with Multivessel Coronary Artery Disease Who Underwent Myocardial Revascularisation

Background: Peptides of the apelinergic system may participate in the development of atherosclerosis, but their role in atherogenesis is unclear. The aim of the study was to evaluate the levels of apelinergic system peptides, such as Elabela (Ela), apelin-13 (AP-13), apelin-17 (AP-17) and apelin receptor (APJ) in the serum and epicardial adipose tissue (EAT) of patients with multivessel coronary artery disease (CAD) who underwent myocardial revascularisation surgery. Methods: The participants comprised 51 CAD patients and 34 healthy adults. Concentrations of Ela, AP-13, AP-17 and APJ were determined by ELISA kits. We analysed the demographics, and clinical and laboratory parameters of the CAD patients. Results: We showed that the serum Ela and AP-17 levels significantly decreased, and APJ significantly increased, in the CAD patients in comparison to the healthy control. A significant relationship between the serum and EAT concentrations of Ela and APJ (p < 0.05) was observed. Positive correlations were found between the serum levels of AP-13 and AP-17, and between AP-17 and APJ. There was a positive correlation between the tissue levels of AP-17 and APJ. The tissue Ela concentration negatively correlated with the BMI, TCH and LDL levels. AP-13 in EAT was negatively associated with the glucose level. In contrast, the tissue APJ showed a positive correlation with TCH concentration. Good diagnostic potential of ELA, AP-17 and APJ was observed for CAD prediction (p < 0.001 for all). Conclusions: The results indicate that the levels of apelinergic peptides are altered in patients with CAD, which may be a potential diagnostic indicator.

Influence of the Apelinergic System on Conduction Disorders in Patients after Myocardial Infarction

BACKGROUND

There is a growing body of evidence for an important role of the apelinergic system in the modulation of cardiovascular homeostasis. The aim of our study was to (1) examine the relationship between apelin serum concentration at index myocardial infarction (MI) and atrioventricular conduction disorders (AVCDs) at 12-month follow-up, and (2) investigate the association between initial apelin concentration and the novel marker of post-MI scar (Q/QRS ratio) at follow-up.

METHODS

In 84 patients with MI with complete revascularization, apelin peptide serum concentrations for apelin-13, apelin-17, elabela (ELA) and apelin receptor (APJ) were measured on day one of hospitalization; at 12-month follow-up, 54 of them underwent thorough examination that included 12-lead electrocardiography (ECG), Holter ECG monitoring and echocardiography.

RESULTS

The mean age was 58.9 years. At 12-month follow-up, AVCDs were diagnosed in 21.4% of subjects, with AV first-degree block in 16.7% and sinoatrial arrest in 3.7%. ELA serum concentration at index MI correlated positively with the occurrence of AVCD (p = 0.003) and heart rate (p = 0.005) at 12-month follow-up. The apelin-13 serum concentration at index MI correlated negatively with the Q/QRS ratio.

CONCLUSIONS

The apelin peptide concentration during an acute phase of MI impacts the development of AVCD and the value of Q/QRS ratio in MI survivors.

Cardiovascular aspects of ELABELA: A potential diagnostic biomarker and therapeutic target

ELABELA, an early endogenous ligand for the G protein-coupled receptor APJ (apelin peptide jejunum, apelin receptor), has been known as an important regulator in cardiovascular homeostasis and may be a novel therapeutic target for multiple cardiovascular diseases (CVDs). At the physiological level, ELABELA exhibits angiogenic and vasorelaxant effects and is essential for heart development. At the pathological level, circulating ELABELA levels may be a novel diagnostic biomarker for various CVDs. ELABELA peripherally displays antihypertensive, vascular-protective, and cardioprotective effects, whereas central administration of ELABELA elevated BP and caused cardiovascular remodeling. This review highlights the physiological and pathological roles of ELABELA in the cardiovascular system. Enhancement of the peripheral ELABELA may be a promising pharmacological therapeutic strategy for CVDs.

A Novel Peptide Elabela is Associated with Hypertension-Related Subclinical Atherosclerosis

INTRODUCTION

Elabela is a newly identified peptide which, alongside apelin, acts as an endogenous ligand that activates the angiotensin receptor-like 1 receptor. Previous studies have shown the association of elabela with hypertension, but information about the role of elabela in hypertension-related subclinical atherosclerosis is scarce.

AIM

We aimed to determine the elabela levels in hypertensive patients and explore its association with subclinical atherosclerosis.

METHODS

A total of 104 subjects with hypertension were included in the study. Elabela levels were measured using an enzyme-linked immunosorbent assay, by first extracting the peptide following the manufacturer's instructions. Subclinical atherosclerosis was assessed by measuring the carotid intima-media thickness (IMT) using ultrasound.

RESULTS

Compared to stage 1, elabela levels decreased in stage 2 hypertension (0.23 [0.13, 0.45] ng/ml vs. 0.14 [0.09, 0.23] ng/ml; P = 0.000), and in the group with increased carotid IMT compared to normal IMT (0.24 [0.13, 0.38] ng/ml vs. 0.15 [0.10, 0.23] ng/ml; P = 0.005). Additionally, a linear correlation analysis showed that elabela had a significant negative correlation with systolic blood pressure (r = - 0.340, P = 0.000) and carotid IMT (r = - 0.213; P = 0.030). In multivariate analysis, lower elabela levels were associated with a higher cardiovascular risk group in this study (OR 5.0, 95% CI 1.8-13.5, P < 0.001).

CONCLUSIONS

This study demonstrated for the first time that circulating elabela declined in a higher stage of hypertension and hypertensive patients with increased carotid IMT, implicating that elabela may be involved in the pathogenesis of hypertension-associated subclinical atherosclerosis.

Elabela Attenuates the TGF-β1-Induced Epithelial-Mesenchymal Transition of Peritoneal Mesothelial Cells in Patients Receiving Peritoneal Dialysis

Peritoneal fibrosis (PF), a common complication in patients receiving peritoneal dialysis (PD), is primarily caused by the epithelial-mesenchymal transition (EMT) of human peritoneal mesothelial cells (HPMCs). PF is the main reason for patients on PD to withdraw from PD. Effective treatment is unavailable for this complication at present. Elabela (ELA) is a polypeptide hormone secreted by the vascular endothelium and kidney. Peptide hormones ELA and apelin (APLN) have various protective effects on the cardiovascular and urinary systems and have potential therapeutic effects on organ fibrosis. ELA and APLN are less studied in PD population. Here, we aimed to investigate the clinical significance of ELA in patients on PD and to evaluate the therapeutic effect of ELA on EMT of HPMCs. Compared with those in patients with stage 5 chronic kidney disease who are not on dialysis, serum ELA levels in patients on PD increased with the improvement of residual renal function at PD duration &lt;36 months and decreased to pre-dialysis levels at PD duration ≥36 months, suggesting that dialysis duration is the main risk factor affecting serum ELA levels in patients on PD. In addition, serum APLN levels decreased in the early stage of PD and recovered to the pre-dialysis level with the prolongation of dialysis time. Notably, serum APLN levels were positively correlated with dialysis duration in patients undergoing PD. To establish the EMT model, we stimulated HPMCs using transforming growth factor-beta 1 (TGF-β1) in cell experiments performed in vitro. ELA-32 treatment reversed the TGF-β1-induced reduction in the expression of the epithelial cell marker and suppressed the expression of mesenchymal cell markers by inhibiting the phosphorylation of SMAD2/3, ERK1/2, and AKT. Therefore, our findings imply that ELA-32 can interfere with the EMT of HPMCs by inhibiting the activation of the TGF-β/SMAD2/3, ERK1/2, and AKT pathways, providing novel insights on the potential therapeutic use of ELA for treating PD-related PF.