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Background: Extracellular matrix metabolism and cardiac cell death participate centrally in myocardial infarction (MI). This study tested the roles of collagenolytic cathepsin K (CatK) in post-MI left ventricular remodeling., Methods and Results: Patients with acute MI had higher plasma CatK levels (20.49 ± 7.07 pmol/L, n = 26) than those in subjects with stable angina pectoris (8.34 ± 1.66 pmol/L, n = 28, P = .01) or those without coronary heart disease (6.63 ± 0.84 pmol/L, n = 93, P = .01). CatK protein expression increases in mouse hearts at 7 and 28 days post-MI. Immunofluorescent staining localized CatK expression in cardiomyocytes, endothelial cells, fibroblasts, macrophages, and CD4 + T cells in infarcted mouse hearts at 7 days post-MI. To probe the direct participation of CatK in MI, we produced experimental MI in CatK-deficient mice (Ctsk -/- ) and their wild-type (Ctsk +/+ ) littermates. CatK-deficiency yielded worsened cardiac function at 7 and 28 days post-MI, compared to Ctsk +/+ littermates (fractional shortening percentage: 5.01 ± 0.68 vs. 8.62 ± 1.04, P < .01, 7 days post-MI; 4.32 ± 0.52 vs. 7.60 ± 0.82, P < .01, 28 days post-MI). At 7 days post-MI, hearts from Ctsk -/- mice contained less CatK-specific type-I collagen fragments (10.37 ± 1.91 vs. 4.60 ± 0.49 ng/mg tissue extract, P = .003) and more fibrosis (1.67 ± 0.93 vs. 0.69 ± 0.20 type-III collagen positive area percentage, P = .01; 14.25 ± 4.12 vs. 6.59 ± 0.79 α-smooth muscle actin-positive area percentage, P = .016; and 0.82 ± 0.06 vs. 0.31 ± 0.08 CD90-positive area percentage, P = .008) than those of Ctsk +/+ mice. Immunostaining demonstrated that CatK-deficiency yielded elevated cardiac cell death but reduced cardiac cell proliferation. In vitro studies supported a role of CatK in cardiomyocyte survival., Conclusion: Plasma CatK levels are increased in MI patients. Heart CatK expression is also elevated post-MI, but CatK-deficiency impairs post-MI cardiac function in mice by increasing myocardial fibrosis and cardiomyocyte death., (Copyright © 2018. Published by Elsevier Ltd.)

Myocardial infarction (MI) is one of the leading causes of death especially in developed countries. Although the advent of early myocardial reperfusion therapy contributes to decreasing the mortality of patients with MI, cardiac ischemia-reperfusion injury and adverse remodeling during the repair process still remain the major factors impairing cardiac function and resulting in unsatisfactory prognosis. Excessive inflammation and immune responses play a crucial role during the whole process of MI. Regulatory T lymphocytes, characterized by immunosuppressive capacity, are associated with many immune-related diseases. Recent studies have proven a protective role of regulatory T cells in MI, which is mainly achieved by modulating inflammation and immune responses. In this review, we will summarize current knowledge of regulatory T lymphocytes, and highlight their roles in the onset of MI, ischemia-reperfusion injury, as well as post-infarct cardiac healing and remodeling., (Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.)

Background: Extracellular matrix (ECM) turnover plays an important role in left ventricular (LV) remodelling following myocardial infarction (MI). Cysteinyl cathepsins contribute to ECM catabolism in arterial diseases, suggesting their participation in post-MI remodelling., Methods and Results: Left anterior descending artery ligation-induced MI in mice showed increased expression and activity of cathepsin S (CatS). Administration of a non-selective cathepsin inhibitor, E64d, aggravated LV dysfunction at 7 and 28 days post-MI. Mechanistic studies showed that E64d increased post-MI inflammatory cell accumulation and cytokine expression, but did not affect apoptosis or angiogenesis in infarcted myocardium. Furthermore, E64d suppressed TGF-β1-induced Smad2 and Smad3 activation and expression of fibronectin extra domain A (ED-A), an alternatively spliced fibronectin variant, and subsequently prevented cardiac fibroblast trans-differentiation into myofibroblast, which contributed to post-MI collagen and fibronectin synthesis and deposition. Consistently, selective inhibition or genetically determined deficiency of CatS also reduced myocardial Smad2 and Smad3 activation and ED-A fibronectin expression, thus suppressing fibroblast trans-differentiation and resulting in adverse collagen turnover and impaired cardiac function-recapitulating the findings in mice treated with E64d., Conclusion: Along with its established activities in ECM degradation, CatS plays novel roles in TGF-β1 signalling, myofibroblast trans-differentiation, and ECM protein synthesis, thereby regulating scar formation in the infarcted myocardium and preserving LV function after experimental MI.

A meta-analysis was performed to address the efficacy and safety of paclitaxel-eluting stent (PES) in ST-segment elevation myocardial infarction (STEMI) patients. A systematic literature search was conducted to identify all randomized clinical trials in mortality, recurrent myocardial infarction (rMI), repeat revascularization (RR), and stent thrombosis (ST). A total of 4190 STEMI patients were enrolled in six randomized trials comparing PES with bare-metal stent (BMS). The pooled repeat revascularization rate was 5.7% in PES group, significantly lower than 10.0% in BMS group with an odds ratio (OR) of 0.56, 95% confidence interval (CI) [0.44, 0.72] (P<0.00001). No significant difference was found between PES and BMS groups in mortality at one year after the indexing procedure (3.9% vs. 5.1%, OR 0.88, 95% CI [0.63, 1.21], P=0.42). Similarly, rMI rate did not differ significantly between the two groups (3.4% vs. 4.1%, OR 0.80, 95% CI [0.56, 1.13], P=0.21). PES was also associated with the comparable pooled rate of definite stent thrombosis with BMS (2.3% vs. 2.4%, OR 0.81, 95% CI [0.52, 1.26], P=0.35). The results show that PES improved clinical outcomes in STEMI patients with a decreased need for repeat revascularization and no concerns for safety.

Background: The benefits and safety of sirolimus-eluting stent (SES) have not been systematically quantified in different trials in ST-segment elevation myocardial infarction (STEMI) patients with primary or rescue percutaneous coronary intervention (PCI). A meta-analysis of randomised trials comparing SES and bare-metal stent (BMS) was performed., Methods: A systematic literature search was conducted to identify all randomized clinical trials. The primary outcome was the rate of major adverse cardiac events (MACEs). The secondary outcomes included death, recurrent myocardial infarction, recurrent revascularization, and stent thrombosis., Results: Totally, 1973 STEMI patients were enrolled in seven eligible randomized trials comparing SES with BMS. The pooled rate of major adverse cardiac events was significantly lower in the SES group than in the BMS group (9.7% vs 20.3%, OR 2.45, 95% CI 1.88-3.19, P < 0.00001). No significant difference in all causes of death was found between the SES and BMS groups, as well as in the pooled recurrent myocardial infarction rates. The pooled recurrent revascularization rate was significantly lower in the SES group than in the BMS group (5.1% vs 14.8%, OR 3.30, 95% CI 2.37-4.60, P < 0.00001). No significant difference was found between the pooled rates of stent thrombosis (1.2% in the SES group and 2.0% in the BMS group, OR 1.61, 95% CI 0.79-3.26, P = 0.19)., Conclusions: SES is associated with a decreased risk of major adverse cardiac events compared with BMS by the greater reduction in repeat revascularization in STEMI patients. Larger trials with longer follow up are warranted to better define the role of SES in STEMI.

Objective: To investigate the effect of long-term administration of fluvastatin on improvement of ventricular remodeling of rats after myocardial infarction and its mechanism., Methods: Sprague-Dawley rats were subjected to ligation in anterior descending branch of coronary artery and treated with fluvastatin (20 mg.kg(-1) d(-1)) or distilled water for 8 weeks. Doppler echocardiography, hemodynamic study and cardiac histomorphometry were used to estimate the ventricular remodeling and cardiac function. Laser scanning confocal microscope was used to definite the distribution of superoxide anion (O(2)(*-)) and nitrogen monoxide. RT-PCR and immunohistochemistry were used to detect the expression of NOS2 and p22phox in mRNA and protein level. The level of lipid peroxidation, glutathione peroxidase, nitrogen monoxide and total cholesterol were detected too., Results: Administration of fluvastatin ameliorated left ventricular remodeling without affecting the infarct size [(40 +/- 6 vs 42 +/-5)%, P>0.05]. The level of left ventricular end-diastolic pressure [(18.24 +/-6.58 vs 10.74 +/-4.71) mmHg, P<0.05], right ventricular ameliorated relative weight [(0.92 +/-0.19 vs 0.71 +/-0.13) g/kg, P<0.05], the thickness of left ventricular posterior wall [(3.04 +/-0.28 vs 2.60 +/-0.36) mm, P<0.05] decreased after fluvastatin treatment. The left ventricular ejection fraction was not influenced, the relative lung weight and the left atrium diameter reduced [(5.79 +/-2.92 vs 3.69 +/-0.68) g/kg, (0.55 +/-0.12 vs 0.45 +/-0.04) mm, P<0.05]; the expressions of LPO in the plasma and myocardium [(8.64 +/-0.59 vs 7.71 +/-0.66) U/dl, P<0.05; (3.12 +/-0.38 vs 1.93 +/-0.40) ng/microg.pro, P<0.01] were reduced, and the overexpressed NO was inhibited [(436.87 +/-47.22 vs 313.78 +/-34.35) mg/dl, P<0.01], but the expression of GPx increased [(66.13 +/-8.31 vs 79.78 +/-2.38) mg/dl, P<0.01]. The expression of O(2)(*-) and the activity of NADPH oxidase subunit p22phox increased; NOS2 and its products NO were over-expressed too., Conclusion: Ventricular remodeling and hemodynamics are improved profoundly in MI rats treated with fluvastatin. The effect of antioxidative stress of fluvastatin might be involved in the mechanism.

IgE has a key role in the pathogenesis of allergic responses through its ability to activate mast cells via the receptor FcεR1. In addition to mast cells, many cell types implicated in atherogenesis express FcεR1, but whether IgE has a role in this disease has not been determined. Here, we demonstrate that serum IgE levels are elevated in patients with myocardial infarction or unstable angina pectoris. We found that IgE and the FcεR1 subunit FcεR1α were present in human atherosclerotic lesions and that they localized particularly to macrophage-rich areas. In mice, absence of FcεR1α reduced inflammation and apoptosis in atherosclerotic plaques and reduced the burden of disease. In cultured macrophages, the presence of TLR4 was required for FcεR1 activity. IgE stimulated the interaction between FcεR1 and TLR4, thereby inducing macrophage signal transduction, inflammatory molecule expression, and apoptosis. These IgE activities were reduced in the absence of FcεR1 or TLR4. Furthermore, IgE activated macrophages by enhancing Na+/H+ exchanger 1 (NHE1) activity. Inactivation of NHE1 blocked IgE-induced macrophage production of inflammatory molecules and apoptosis. Cultured human aortic SMCs (HuSMCs) and ECs also exhibited IgE-induced signal transduction, cytokine expression, and apoptosis. In human atherosclerotic lesions, SMCs and ECs colocalized with IgE and TUNEL staining. This study reveals what we believe to be several previously unrecognized IgE activities that affect arterial cell biology and likely other IgE-associated pathologies in human diseases. [ABSTRACT FROM AUTHOR]

Abstract: Background: Reperfusion therapy is widely utilized for acute myocardial infarction (AMI), so ischemia/reperfusion (I/R) of the heart is frequently encountered in clinical practice. The curative effects of reperfusion therapy for AMI are favourable in most cases, but reperfusion can also cause harmful effect to cardiomyocytes. Hydroxysafflor yellow A (HSYA) is an effective therapeutic agent to alleviate I/R injury, but the mechanisms underlying this therapeutic effect are unknown. Methods and results: The H9c2 cardiomyocyte cell line was incubated with or without HSYA during hypoxia, then it was reoxygenated. In the presence of HSYA, reoxygenation resulted in the upregulated expression and activity of heme oxygenase-1 (HO-1), phosphorylation of Akt, translocation of nuclear factor Nrf2, and most importantly, a reduction in A/R-induced apoptosis. An HO-1 inhibitor completely suppressed HO-1 enzymatic activity upregulated by HSYA and notably diminished the anti-apoptotic effect of HSYA. An inhibitor of PI3K, completely blocked Akt phosphorylation induced by HSYA and partly negated HSYA-induced upregulation of HO-1, translocation of nuclear factor Nrf2 and suppression of apoptosis in the H9c2 cardiomyocytes. Conclusions: Our study suggests that HSYA can provide protection to H9c2 cardiomyocytes against A/R-induced apoptosis. This protective effect largely depends on the upregulation of HO-1 expression through the PI3K/Akt/Nrf2 signaling pathway. [Copyright &y& Elsevier]