Knockdown of GAS5 Inhibits Atherosclerosis Progression via Reducing EZH2-Mediated ABCA1 Transcription in ApoE-/- Mice.

Atherosclerosis is a disorder occurring in the large arteries and the primary cause of heart diseases. Accumulating evidence has implicated long non-coding RNAs (lncRNAs) in atherosclerosis. This study aims to clarify the potential effects of lncRNA growth arrest-specific 5 (GAS5) on cholesterol reverse-transport and intracellular lipid accumulation in atherosclerosis. GAS5 was mainly localized in the nucleus and highly expressed in the human monocytic leukemia cell line (THP-1) macrophage-derived foam cells in coronary heart disease. Overexpressed GAS5 increased THP-1 macrophage lipid accumulation. Of note, GAS5 can inhibit the expression of ATP-binding cassette transporter A1 (ABCA1) by binding to enhancer of zeste homolog 2 (EZH2). Overexpression of EZH2 reduced cholesterol efflux and ABCA1 expression. EZH2 promoted triple methylation of lysine 27 (H3K27) in the ABCA1 promoter region. Subjected to overexpressed GAS5, overexpressed EZH2, or downregulated ABCA1, the Apolipoprotein E (ApoE)-/- mice with atherosclerosis showed increased total cholesterol (TC), free cholesterol (FC), cholesterol ester (CE), low-density lipoprotein (LDL) levels, aortic plaque, and lipid accumulation, accompanied by reduced high-density lipoprotein (HDL) level and cholesterol outflow. Altogether, knockdown of GAS5 can potentially promote reverse-transportation of cholesterol and inhibit intracellular lipid accumulation, ultimately preventing the progression of atherosclerosis via reducing EZH2-mediated transcriptional inhibition of ABCA1 by histone methylation.

Values of aortic dissection detection risk score combined with ascending aorta diameter >40 mm for the early identification of type A acute aortic dissection.

BACKGROUND: Type A acute aortic dissection (A-AAD), involving the ascending aorta, is a life-threatening disease. To detect A-AAD early and rapidly in patients with acute chest pain, especially in patients with acute myocardial infarction (AMI) secondary to A-AAD, we investigated values of combined use of the risk score and the ascending aorta diameter >40 mm for the early identification of A-AAD. METHODS: Our study retrospectively encompassed 239 patients with acute chest pain on admission to our hospital between July 2010 and December 2016. The risk score was calculated according to the aortic dissection detection (ADD) risk score system, and the ascending aorta diameter was accurately obtained from the transthoracic echocardiography (TTE). RESULTS: A risk score ≥1 had an excellent sensitivity of 94.9% and a fair negative predictive value (NPV) of 77.8%, with a poor specificity of 8.7% and a positive predictive value (PPV) of 33.5% for the diagnosis of A-AAD. A risk score ≥2 had an excellent specificity of 91.3% and a fair NPV of 73.1%, whereas it had a lower sensitivity of 30.8% and a PPV of 63.2%. A risk score ≥1, combined with an ascending aorta diameter >40 mm, had a sensitivity, a specificity, a PPV, and an NPV of 84.6%, 87.6%, 76.7%, and 92.2% for the diagnosis of A-AAD, respectively. The combined use of a risk score ≥2 and an ascending aorta diameter >40 mm had an excellent specificity of 98.1% and a PPV of 86.4%, a fair NPV of 72.8%, and a poor sensitivity of 24.4% for the detection of A-AAD. Moreover, the omission diagnostic rate for A-AAD was significantly decreased from 33.3% to 7.4% using a risk score ≥1 combined with an ascending aorta diameter >40 mm in patients with AMI secondary to A-AAD. CONCLUSIONS: The combined use of an ADD risk score ≥1 and an ascending aorta diameter >40 mm was highly indicative of A-AAD in patients presenting with acute chest pain, especially in patients with AMI secondary to A-AAD, which urgently needed computed tomography angiography (CTA) or magnetic resonance imaging (MRI) to confirm the diagnosis of A-AAD.

Hyperlipidemia induces vascular smooth muscle cell proliferation involving Wnt/ß-catenin signaling.

Hyperlipidemia has been shown to stimulate vascular smooth muscle cell (VSMC) proliferation. Wnt signaling pathway plays a critical role in embryonic development and cell proliferation. In this study, Sprague-Dawley rats fed with high-fat or normal diet for 12 weeks were sacrificed, and the thoracic aorta was harvested to determine wnt3a, ß-catenin, T-cell factor 4 (TCF4), and cyclin D1 expressions. VSMC proliferation within thoracic aorta and lipid accumulation within VSMCs were detected. Rat aortic VSMCs were cultured in serum from rats with hyperlipidemia or DKK-1; Wnt3a, ß-catenin, TCF4, and cyclin D1 expressions, and cell cycle distribution were determined. The findings demonstrated that increased number of VSMCs, lipid droplets, and vacuoles within thoracic aorta in the high-fat-fed group. Compared with controls, VSMCs from high-fat-fed rats showed higher mRNA expressions of wnt3a, ß-catenin, TCF4, and cyclin D1, as well as in VSMCs cultured with hyperlipidemic serum. After 24 h, VSMCs stimulated with hyperlipidemic serum showed significantly increased cell number and S-phase entry compared with cells exposed to normolipidemic serum. These effects were blocked by DKK-1. These results suggest that Wnt/ß-catenin signaling plays an important role in hyperlipidemia-induced VSMC proliferation.

Overexpression of vasostatin-1 protects hypoxia/reoxygenation injuries in cardiomyocytes independent of endothelial cells.

INTRODUCTION: Vasostatin-1 (VS-1) has been suggested in protecting hypoxia/reoxygenation (H/R) injuries in isolated hearts. However, the molecular mechanisms remained to be elucidated. METHODS: Cardiomyocytes were treated with recombinant Ad-VS-1 adenoviral vector before H/R. Cell viability was studied using MTT methods and annexin V-FITC flow cytometry. Intracellular oxidative stress was measured by superoxide dismutase (SOD) and malondialdehyde (MDA), and inflammatory reactions by enzyme-linked immunosorbent assay (ELISA). Measurement of myocardial nitrous oxide synthase (NOS) was determined by serum nitric oxide (NO) concentrations using nitrite reductase and endothelial nitric oxide synthase (eNOS) by Western blotting. Inhibitors of the NOS system, including hemoglobin and KT5823, were applied to verify the results. RESULTS: In comparison of the blank group, cardiac myocytes overexpressing VS-1 showed significant decrease in apoptosis, intracellular oxidative stress, and inflammatory reactions (P < 0.05). In addition, serum NO concentrations and expression of eNOS were notably enhanced (P < 0.05). These protective effects of VS-1 were suppressed in the presence of apoptosis-inducing agents. CONCLUSIONS: Overexpression of VS-1 in cardiomyocytes could limit the H/R injuries at molecular levels. The protective effects were independent of endothelial cell function, suggestive of a potential therapeutic target for patients with myocardial ischemia in the future.

Early outcomes of isolated coronary artery bypass grafting in Chinese aged patients with diabetes mellitus.

OBJECTIVE: To compare the early outcomes of coronary artery bypass grafting (CABG) in aged diabetic patients, and evaluate the affection of diabetes on the early outcomes of CABG in aged patients. METHODS: The study took place in the Department of Cardiovascular Surgery, Shanghai Jiao Tong University Affiliated First People's Hospital, Shanghai, China, between January 2000 and July 2008. Five hundred and ninety-three elderly patients (age > or = 70-years-old), undergoing isolated CABG were retrospectively divided into diabetic group and non-diabetic group. We analyzed the pre-operative, intra-operative, and post-operative variables of the 2 groups. The t-test, Chi-square test, and multivariate logistic regression were used to determine the differences between the 2 groups of patients. RESULTS: There was no statistical difference of pre-operative and intraoperative variables between the 2 groups, except that there were more left main coronary artery diseases in the diabetic group. Values in the post-operative period such as morbidity, complications, and blood infusion had no differences between the 2 groups. Diabetes mellitus and age are not the risk factors for in-hospital mortality. CONCLUSION: Coronary artery bypass grafting in elderly patients is plausible. Furthermore, diabetic patients could get the same surgical results as those non-diabetic patients.

A prospective evaluation of apolipoprotein M gene T-778C polymorphism in relation to coronary artery disease in Han Chinese.

OBJECTIVES: Apolipoprotein M (apoM) is important for the formation of pre-beta-high-density lipoprotein (HDL) and cholesterol efflux in macrophages. It is demonstrated that single-nucleotide polymorphism (SNP) T-778C of apoM gene is related to type 2 diabetes in Han Chinese. In the present study, we investigated the possible association of apoM polymorphism in relation to coronary artery disease (CAD) in Han Chinese. DESIGN AND METHODS: This case-controlled study consisted of 118 CAD patients who were diagnosed angiographically to have at least 30% stenosis, and 255 unrelated subjects who were used as control. ApoM gene polymorphism in the proximal promoter region was analyzed by PCR-RFLP and serum lipid levels were also measured. RESULTS: It is indicated that CAD patients had increased frequency of C allele on apoM T-778C compared to the controls (14.8% vs. 6.9%, P=0.0008). Multivariable logistic regression analysis indicated that odds ratios (ORs) for all subjects with apoM CC+CT genotypes and C allele were 1.9 (95% CI=1.1-2.9, P<0.0001) and 1.9 (95% CI=1.3-3.2, P<0.0001), respectively. The plasma total cholesterol (TC) levels were significantly higher in individuals with CC or CT genotype than those with TT genotype in both CAD patients and controls. CONCLUSIONS: The present findings suggest that the C allele at nucleotide -778 in the apoM gene is a risk factor for genetic susceptibility to CAD and is also associated with TC levels in Han Chinese.

Significance of changes in transforming growth factor-beta mRNA levels in autogenous vein grafts.

BACKGROUND: This study was designed to investigate changes in mRNA levels of transforming growth factor-beta (TGF-beta), collagen I, and collagen III in autogenous vein grafts. METHODS: Twenty-four New Zealand rabbits were randomly divided into 4 groups with 6 rabbits each. The external jugular veins of the New Zealand rabbits were harvested and grafted into the ipsilateral carotid artery. All rabbits were fed with a standard diet. After the operation, the rabbits were sacrificed at 1, 2, 3, or 4 weeks. TGF-beta, collagen I, and collagen III mRNA levels in the venous grafts were measured by semiquantitative methods at every time point. The contralateral external jugular veins were also harvested and analyzed as controls. Glyceraldehyde-3-phosphate dehydrogenase was used as an internal standard to normalize all samples for potential variations in mRNA content. In order to observe the expression of TGF-beta protein, immunohistochemical SABC methods were used. RESULTS: One week postoperation, the mRNA level of TGF-beta was upregulated to 1.73 +/- 0.19 in the vein graft and 1.21 +/- 0.16 in the control vein (P < 0.01). High mRNA levels were maintained until week 4 postoperation. The mRNA levels of collagen I and collagen III were also significantly increased to 2.18 +/- 0.21 versus 1.12 +/- 0.24 and 1.08 +/- 0.13 versus 0.83 +/- 0.12, respectively (P < 0.05). Immunohistochemical staining revealed a higher density of TGF-beta expression in the vein grafts. CONCLUSIONS: An uninterrupted increase in mRNA levels of TGF-beta, collagen I, and collagen III is observed in autogenous vein grafts. This increase may be the major cause of intimal hyperplasia, sclerosis, and even graft failure.

[Establishment of model human stem cell of transplantation into myocardium of chick embryos].

OBJECTIVE: To establish an animal model of human stem cell transplantation into myocardium in chick embryos. METHODS: Hoechsst 33,258 labeled human primordial germ cells (hPGC) were microsurgically injected into the myocardium of 633 chick embryos of 3-4 days development. Ten days after, the hearts were isolated from the 94 surviving chick embryos, embedded, and sliced. In situ hybridization (ISH) with human specific DNA Alu probe was conducted on the sections with fluorescence to detect the existence of transplanted PGC. Immunohistochemistry with human-myocardium-specific antibody cTnT was conducted on the adjacent sections to observe the differentiation of human myocardial cells. RESULTS: ISH showed that PGC were detected in the myocardium of chick embryos 10 days post-operationally. Immunohistochemistry showed that the myocardium added with antibody in adjacent sections was cTnT-positive and the myocardium untreated with antibody was cTNT-negative. Successful cell transplantation occurred in 15.3% +/- 2.4% of chick embryos. CONCLUSION: Establishment of an animal model of cell transplantation of human stem cells into myocardium in chick embryos is feasible.