Detection of Left Ventricular Remodeling in Acute ST Elevation Myocardial Infarction after Primary Percutaneous Coronary Intervention by Two Dimensional and Three Dimensional Echocardiography

Clinical Variables Influence the Ability of miR-101, miR-150, and miR-21 to Predict Ventricular Remodeling after ST-Elevation Myocardial Infarction

Left ventricle remodeling (LVR) after acute myocardial infarction (MI) leads to impairment of both systolic and diastolic function, a significant contributor to heart failure (HF). Despite extensive research in the field, predicting post-MI LVR and HF is still a challenge. Several circulant microRNAs have been proposed as LVR predictors; however, their clinical value is controversial. Here, we used real-time quantitative PCR to quantify the plasma levels of hsa-miR-101, hsa-miR-150, and hsa-miR-21 on the first day of hospital admission of MI patients with ST-elevation (STEMI). We analyzed their correlation to the patient's clinical and paraclinical variables and evaluated their ability to discriminate between post-MI LVR and non-LVR. We show that, despite being excellent MI discriminators, none of these microRNAs can distinguish between LVR and non-LVR patients. Furthermore, we found that diabetes mellitus (DM), Hb level, and the number of erythrocytes significantly influence all three plasma microRNA levels. This suggests that plasma microRNAs' diagnostic and prognostic value in STEMI patients should be reevaluated and interpreted in the context of associated pathologies.

Predictive value of early left ventricular end-diastolic volume changes for late left ventricular remodeling after ST-elevation myocardial infarction

BACKGROUD

Left ventricular remodeling (LVR) is a major predictor of adverse outcomes in patients with acute ST-elevation myocardial infarction (STEMI). This study aimed to prospectively evaluate LVR in patients with STEMI who were successfully treated with primary percutaneous coronary intervention (PCI) and examine the relationship between early left ventricular dilation and late LVR.

METHODS

Overall 301 consecutive patients with STEMI who underwent primary PCI were included. Serial echocardiography was performed on the first day after PCI, on the day of discharge, at 1 month, and 6 months after discharge.

RESULTS

Left ventricular remodeling occurred in 57 (18.9%) patients during follow-up. Left ventricular end-diastolic volume (LVEDV) reduced from day 1 postoperative to discharge in the LVR group compared with that in the non-LVR (n-LVR) group. The rates of change in LVEDV (ΔLVEDV%) were -5.24 ± 16.02% and 5.05 ± 16.92%, respectively (p < 0.001). LVEDV increased in patients with LVR compared with n-LVR at 1-month and 6-month follow-ups (ΔLVEDV% 13.05 ± 14.89% vs. -1.9 ± 12.03%; 26.46 ± 14.05% vs. -3.42 ± 10.77%, p < 0.001). Receiver operating characteristic analysis showed that early changes in LVEDV, including ΔLVEDV% at discharge and 1-month postoperative, predicted late LVR with an area under the curve value of 0.80 (95% confidence interval 0.74-0.87, p < 0.0001).

CONCLUSIONS

Decreased LVEDV at discharge and increased LVEDV at 1-month follow-up were both associated with late LVR at 6-month. Comprehensive and early monitoring of LVEDV changes may help to predict LVR.

Three-dimensional echocardiographic assessment of left ventricular geometric changes following acute myocardial infarction

Acute ST-segment elevation myocardial infarction (STEMI) is associated with left ventricular (LV) structural and functional consequences. We aimed to elucidate LV geometric changes following STEMI using three-dimensional (3D) echocardiography (3DE) and to assess their functional implications using two-dimensional (2D) speckle tracking echocardiography (STE). The study included 71 patients with STEMI who underwent baseline and 6-month follow-up 2D- and 3DE. Measured parameters included LV dimensions, biplane volumes, wall motion assessment, 2D LV global longitudinal strain (GLS), and 3D LV volumes, sphericity index and systolic dyssynchrony index. According to 3DE, LV geometric changes were classified as, adverse remodeling, reverse remodeling, and minimal LV volumetric changes. The occurrence of in-hospital and follow-up major adverse cardiovascular events (MACE) was assessed among the study population. The incidence of developing adverse remodeling was 25.4% while that of reverse remodeling was 36.6%. Adverse remodeling patients had significantly higher in-hospital MACE. Reverse remodeling was associated with significantly improved GLS, that was less evident in those with minimal LV geometric changes, and non-significant improvement for adverse remodeling group. LV baseline 2D GLS significantly correlated with follow-up 3D volumes among both reverse and adverse remodeling groups. Female gender and higher absolute GLS change upon follow-up were significantly associated with reverse remodeling. ROC-derived cutoff for adverse remodeling reallocated a substantial number of patients from the minimal change group to the adverse remodeling. Following acute STEMI, two-dimensional GLS was associated with and potentially predictive of changes in LV volumes as detected by three-dimensional echocardiography.

Growth Differentiation Factor 15 is Related with Left Ventricular Recovery in Patients with ST-Elevation Myocardial Infarction after Successful Reperfusion by Primary Percutaneous Intervention

Background

The determinants of left ventricular (LV) recovery after successful revascularization in ST-elevation myocardial infarction (STEMI) patients are not clear. In addition, the relationship between growth differentiation factor15 (GDF-15) and left ventricular ejection fraction (LVEF) improvement is also unknown. This study hypothesizes that a low GDF-15 level would be associated with LVEF recovery.

Methods

One hundred and sixty-one STEMI patients were included in this study. Echocardiographic examinations were performed before and 12-18 weeks after discharge. The patients were divided into three groups according to the changes in LVEF as 62 patients with ≥ 10% change, 47 patients with 1-9% change, and 52 patients ≤ 0% change. LV recovery was defined as ≥ 10% LVEF improvement and the predictors of LV recovery were investigated. Moreover, two groups were created according to GDF-15 values, and the follow-up/baseline echocardiographic parameters were compared between these groups.

Results

LV recovery was detected in 38.5% of the patients. Low baseline LVEF [odds ratio (OR): 0.85, 95% confidence interval (CI) 0.82-0.94, p = 0.001], low GDF-15 (OR: 0.79, 95% CI 0.68-0.93, p = 0.004), previous angina (OR: 2.34, 95% CI 1.10-4.96, p = 0.027), and symptom-to-balloon time (OR: 0.97, 95% CI 0.95-1.00, p = 0.043) were independent predictors of LV recovery. The ratios of follow-up/baseline LV end-diastolic volume index, LV end-systolic volume index and wall motion score index were lower in the low GDF-15 group (0.96 vs. 1.04, p < 0.001; 0.96 vs. 1.10, p < 0.001; 0.89 vs. 0.96, p < 0.001). Moreover, being in the low GDF-15 group was associated with LV recovery (OR: 2.93, 95% CI 1.43-6.02, p = 0.001).

Conclusions

Lower GDF-15 level was associated with better LV improvement and less adverse remodeling in STEMI patients.

Anti-apoptotic Effect of MiR-223-3p Suppressing PIK3C2A in Cardiomyocytes from Myocardial Infarction Rat Through Regulating PI3K/Akt Signaling Pathway

We aimed to explore the regulatory mechanism of the axis of miR-223-3p-PIK3C2A-PI3K/Akt on cardiomyocyte apoptosis in rats with myocardial infarction. Thirty 8-week-old healthy male SD rats were used for establishing the sham group and the model group, with HE staining, TUNEL staining, and TTC staining performed. After the identification of the targeting relationship between PIK3C2A and miR-223-3p, experimental rats were randomly divided into seven groups by plasmid transfection, including the Blank group, negative control (NC) group, miR-223-3p mimic group, miR-223-3p inhibitor group, siRNA-PIK3C2A group, oe-PIK3C2A group, and miR-223-3p inhibitor + oe-PIK3C2A group. Four weeks after transfection, the expression levels of miR-223-3p and PIK3C2A in tissues as well as PI3K, Akt, Bax, and bcl-2 mRNA in cells were detected by qRT-PCR and western blot, in combination with the detection of apoptosis rate by flow cytometry. Compared with the sham group, the model group showed typical myocardial injury and abnormal staining, higher apoptotic index, and larger myocardial infarction area (all P < 0.05). PIK3C2A was the target gene of miR-223-3p. The expression level of miR-223-3p in model group was significantly lower than that in sham group, while the mRNA and protein expression levels of PIK3C2A increased significantly (all P < 0.05). In cell tests, the expression level of miR-223-3p increased significantly in miR-223-3p mimic group (P < 0.05), which, however, showed no significant change in siRNA-PIK3C2A group (P > 0.05). MiR-223-3p inhibitor group and siRNA-PIK3C2A group had obviously increased PI3K, Akt, mTOR and Bcl-2 mRNA, and protein expression, while decreased mRNA and protein expression of PIK3C2A and Bax (all P < 0.05); miR-223-3p mimic groups had the opposite trends (all P < 0.05). siRNA-PIK3C2A + miR-223-3p mimic showed no obvious change relative to the control groups (all P > 0.05). Low expression of miR-223-3p may downregulate PIK3C2A expression, resulting in the inhibition of myocardial cell apoptosis in rats with myocardial infarction via the activation of PI3K/Akt signaling pathway.

Plasma Concentrations of Extracellular Vesicles Are Decreased in Patients with Post-Infarct Cardiac Remodelling

Background, the mechanisms underlying left ventricular remodelling (LVR) after acute myocardial infarction (AMI) remain obscure. In the course of AMI, blood cells and endothelial cells release extracellular vesicles (EVs). We hypothesized that changes in EV concentrations after AMI may underlie LVR. Methods, plasma concentrations of EVs from endothelial cells (CD146+), erythrocytes (CD235a+), leukocytes (CD45+), platelets (CD61+), activated platelets (P-selectin+), and EVs exposing phosphatidylserine after AMI were determined by flow cytometry in 55 patients with the first AMI. LVR was defined as an increase in left ventricular end-diastolic volume by 20% at 6 months after AMI, compared to baseline. Results, baseline concentrations of EVs from endothelial cells, erythrocytes and platelets were lower in patients who developed LVR (p ≤ 0.02 for all). Concentrations of EVs from endothelial cells and erythrocytes were independent LVR predictors (OR 8.2, CI 1.3-54.2 and OR 17.8, CI 2.3-138.6, respectively) in multivariate analysis. Combining the three EV subtypes allowed to predict LVR with 83% sensitivity and 87% specificity. Conclusions, decreased plasma concentrations of EVs from endothelial cells, erythrocytes and platelets predict LVR after AMI. Since EV release EVs contributes to cellular homeostasis by waste removal, decreased concentrations of EVs may indicate dysfunctional cardiac homeostasis after AMI, thus promoting LVR.

PKD deletion promotes autophagy and inhibits hypertrophy in cardiomyocyte

Protein kinase D (PKD) plays an important role in the development of cardiac hypertrophy induced by pressure overload. However, the mechanism involved is unclear. This study, using primary cardiomyocyte culture, PKD knockdown and overexpression, and other molecular techniques, tested our hypothesis that PKD pathway mediates cardiac hypertrophy by negatively regulating autophagy in cardiomyocyte. Neonatal cardiomyocytes were isolated from Wistar rats and cell hypertrophy was induced by norepinephrine treatment (PE, 10^-4 mol/L), and divided into the following groups: (1) Vehicle; (2) PE; (3) PE + control siRNA; (4) PE + Rapamycin (100 nM); (5) PE + PKD-siRNA (2 × 10⁸ U/0.1 ml); (6) PE + PKD siRNA + 3 MA (10 mM). The results showed that PE treatment induced cardiomyocyte hypertrophy, which were confirmed by cell size and biomarkers of cardiomyocyte hypertrophy including increased ANP and BNP mRNA. PKD knockdown or Rapamycin significantly inhibited PE-induced cardiomyocyte hypertrophy. In addition, PKD siRNA increased autophagy activity determined by electron microscopy, increased biomarkers of autophagy by Western blot, accompanied by down-regulated AKT/mTOR/S6K pathway. All the effects of PKD knockout were inhibited by co-treatment with 3-MA, an autophagy inhibitor. Oppositely, the autophagy in cardiomyocytes was inhibited by PKD overexpression. These results suggest that PKD participates in the development of cardiac hypertrophy by regulating autophagy via AKT/mTOR/S6K pathway.