Early resolution of ST-segment elevation after reperfusion therapy for acute myocardial infarction: Its relation to echocardiography-determined left ventricular global and regional function and deformation.

AIMS: To evaluate the relationships between ST-segment resolution (STR) and echocardiography-determined left ventricular (LV) global and regional function and deformation in the sub-acute phase of STEMI. METHODS AND RESULTS: STR, defined as either complete (≥70%) or incomplete (<70%), was evaluated 60minutes after primary percutaneous coronary intervention (PCI) of 84 STEMI patients. Conventional two-dimensional (2D) echocardiography and 2D speckle-tracking echocardiography (STE) were performed at 3-7days after reperfusion. LV deformation [including the infarction-related regional longitudinal (RLS), circumferential (RCS), and radial (RRS) strains, and global longitudinal (GLS), circumferential (GCS), and radial (GRS) strains] was measured by 2D STE. LV segmental function was assessed by wall motion score index (WMSI). Patients in incomplete vs. complete STR groups had higher WMSI (p<0.001); decreased peak amplitude of RLS (p<0.001), RCS (p=0.008), RRS (p=0.002); and decreased peak amplitude of GLS (p<0.001), GCS (p<0.001), GRS (p=0.003). RLS (r=0.27, p=0.015) and GLS (r=0.33, p=0.003) were best correlates of STR at the regional and global level, respectively. CONCLUSIONS: STR correlated with global and regional LV function and deformation in patients with sub-acute phase of STEMI after PCI. RLS and GLS were the strongest correlates of STR at the regional and global levels, respectively.

FOXP3 demethylation as a means of identifying quantitative defects in regulatory T cells in acute coronary syndrome.

OBJECTIVE: The contribution of regulatory T cells (Tregs) to the pathogenesis of acute coronary syndrome (ACS) remains poorly understood. One core obstacle is the lack of Treg-specific markers. A highly conserved CpG enriched element in forkhead box P3 intron 1 (FOXP3 i l) is unmethylated only in Tregs, and measuring the unmethylation of FOXP3 i l can be used to identify the role of Tregs in clinical diseases. This study investigated whether analyzing the demethylation status of FOXP3 i 1 is a more reliable means than using Treg-specific surface markers in ACS. METHODS AND RESULTS: We evaluated circulating Tregs percentages on different levels including cell frequencies (CD4(+)CD25(hi)FOXP3(+)Tregs and CD4(+)CD25(hi)CD45(+)naïve Tregs) or FOXP3 mRNA, FOXP3 i 1 demethylation status and related cytokine secretion in 89 patients with ACS and 35 controls. FOXP3 i 1 demethylation assay showed that the amount of Tregs in ACS patients was significantly reduced than that in controls (p = 0.0005). However, flow cytometry analysis did not identify any reduction of CD4(+)CD25(hi)FOXP3(+)Tregs in ACS patients. Notably, younger patients had higher percentage of CD4(+)CD25(hi)FOXP3(+)Tregs but decreased percentage of CD4(+)CD25(hi)CD45(+)naïve Tregs than either controls or older patients. Furthermore, a DNA hypomethylation agent increased the amount of CD4(+)CD25(hi)FOXP3(+)Tregs and Tregs related cytokine IL-10 and suppressed the production of pro-inflammatory cytokine interferon-γ by inducing FOXP3 i 1 demethylation in vitro. CONCLUSIONS: A quantitative defect of Tregs, suggestive of decreased peripheral tolerance, could be a potential hallmark of ACS disease. Targeting FOXP3 i l demethylation might elevate the inhibitory activity of Tregs in ACS.

[Effect of antiarrhythmic peptide on ventricular arrhythmia induced by lysophosphatidic acid].

OBJECTIVE: To investigate the effect and potential mechanism of lysophosphatidic acid (LPA) and antiarrhythmic peptide (AAP10) on rabbit ventricular arrhythmia. METHODS: Twenty-four rabbits were randomly divided into three groups (n = 8 each): control group, LPA group and AAP10 + LPA group. Using arterially perfused rabbit ventricular wedge preparations, transmural ECG and action potentials from both endocardium and epicardium were simultaneously recorded in the whole process of all experiments with two separate floating microeletrodes. The incidence of ventricular arrhythmia post S1S2 stimulation was recorded. Protein levels of nonphosphorylated Cx43 and total Cx43 were evaluated by Western blot. The distribution of nonphosphorylated Cx43 was observed by confocal immunofluorescence microscopy. RESULTS: Compared with the control group, the QT interval, endocardial action potential duration, transmural repolarization dispersion (TDR) and incidence of ventricular arrhythmia were significantly increased and nonphosphorylated Cx43 expression was significantly upregulated in the LPA group. Compared with the LPA group, cotreatment with AAP10 can reduce the QT interval, endocardial action potential duration, TDR and incidence of ventricular arrhythmia (25.0% vs 62.5%, P < 0.01) and downregulate nonphosphorylated Cx43. CONCLUSIONS: LPA could promote the arrhythmia possibly by upregulating nonphosphorylated Cx43 and subsequent gap junction transmission inhibition. Gap junction enhancer AAP10 could attenuate the pro-arrhythmic effect of LPA probably by downregulating myocardial nonphosphorylated Cx43 expression.

[Kv1.3 potassium channel expression changes after CD4(+) and subsets CD28(null)/CD28(+)T cells activation in peripheral blood of patients with acute coronary syndrome].

OBJECTIVE: To study the Kv1.3 channel expression changes after CD4(+) and subsets CD28(null)/CD28(+)T cells activation in peripheral blood of patients with acute coronary syndrome (ACS). METHODS: CD4(+)T cell in 27 ACS patients and CD4(+)CD28(null)/CD4(+)CD28(+)T cells in 12 out of these 27 ACS patients were isolated from peripheral blood with magnetic cell sorting. The whole-cell Kv1.3 currents for three T cells were recorded with patch-clamp technique before and 72 hours after activation by purified anti-human CD3 Interferon gamma, tumor necrosis factor alpha (TNF-alpha), granzyme B mRNA expression were determined by reverse transcription-PCR before and 72 hours after activation by purified anti-human CD3 in the presence or absence of recombinant Margatoxin (rMgTX, 0.1, 1, 10 nmol/L), a specific Kv1.3 channel blocker. RESULTS: Peak Kv1.3 channel currents of CD4(+), CD4(+)CD28(null), CD4(+)CD28(+)T cells were significantly increased and the mean Kv1.3 channel numbers per cell of these cells were increased by about 90%, 60%, 80% (402 +/- 88 vs. 752 +/- 275, 553 +/- 328 vs. 874 +/- 400, 392 +/- 133 vs. 716 +/- 251, all P < 0.05) after activation compared to baseline values. Baseline CD4(+)CD28(null)T cell numbers were about 40% more than those of CD4(+)CD28(+)T cell (P < 0.05) and were similar after activation (P = 0.102). The mRNA expression of interferon gamma, TNF-alpha and granzyme B were dose-dependently down-regulated by rMgTX. CONCLUSIONS: Kv1.3 channels of peripheral CD4(+)T cell and CD28(null)/CD28(+)T cells from ACS patients significantly increased after activation and Kv1.3-specific channel blocker rMgTX could effectively abolish this effect suggesting a potential role of Kv1.3 channel blocker on plaque stabilization in ACS patients.