Downregulation of microRNA-19b contributes to angiotensin II-induced overexpression of connective tissue growth factor in cardiomyocytes.

OBJECTIVES: The present study was designed to decipher the molecular mechanisms underlying angiotensin (Ang) II-induced overexpression of connective tissue growth factor (CTGF) in cultured cardiomyocytes. METHODS: Cardiomyocytes isolated from 1- to 3-day-old neonatal rats were cultured and treated with 100 nM Ang II with or without pretreatment with 10 nM telmisartan, an Ang II type 1 receptor antagonist. The role of microRNA (miR)-19b in the regulation of Ang II-induced CTGF expression was evaluated in cultured cardiomyocytes with quantitative real-time reverse transcription polymerase chain reaction and Western blot analysis. RESULTS: We provide several lines of evidence to show that miR-19b contributes to the Ang II-induced overexpression of CTGF in cultured cardiomyocytes. Firstly, administration of Ang II decreased the level of miR-19b dramatically (p < 0.05 vs. control), which was abolished by telmisartan. Secondly, Ang II increased the level of CTGF significantly (p < 0.05 vs. control), which was also prevented by pretreatment with telmisartan. Thirdly, overexpression of miR-19b decreased CTGF levels (p < 0.05 vs. control). Finally, transfection of miR-19b into cardiomyocytes prevented the upregulation of CTGF induced by Ang II. CONCLUSION: Downregulation of miR-19b contributes to Ang II-induced overexpression of CTGF in cultured cardiomyocytes.

Correlation of triglycerides with myocardial infarction and analysis of risk factors for myocardial infarction in patients with elevated triglyceride.

BACKGROUND: This study aims to investigate the associations of different (low/medium/high) levels of fasting triglyceride (TG) levels with cardiovascular endpoints. METHODS: This cohort study comprised of in-service and retired employees of the Kailuan Coal Mine Group, who participated in the health examination conducted in 11 hospitals in the Kailuan region from June 2006 to October 2007 (n=100,271). The study population was divided into five groups according to different TG levels. Logistic regression analysis was used to analyze the risk factors for myocardial infarction (MI) in patients with elevated TG, and Cox proportional hazards regression analysis was used to analyze the effects of different TG levels on endpoint events. RESULTS: After a median follow-up of 7 years, 961 patients developed MI and 3,142 subjects died. The multivariate logistic regression analysis revealed that elevated TG, an age of ≥65 years old, body mass index (BMI) >25 kg/m2, fasting blood glucose (FBG) ≥6.1 mmol/L and high density lipoprotein cholesterol (HDL-C) <1.5 mmol/L were all risk factors for MI (P<0.05). Furthermore, Cox proportional hazards regression model revealed that after controlling for gender, age and other factors, with the increase in TG level, the relative risk of MI also increased. Compared to the TG1 group, the risk of MI increased to 1.32 folds in the TG4 group (95% CI: 1.05-1.66, P=0.018) and 1.61 folds in the TG5 group (95% CI: 1.21-1.93, P=0.004). Furthermore, the risk of MI combined with all-cause death and all-cause death also increased, but the differences were not all statistically significant. CONCLUSIONS: In the study population of the Kailuan region, elevated fasting TG increases the risk of MI, particularly in populations with an age of ≥65 years old, BMI >25 kg/m2, FBG ≥6.1 mmol/L and HDL-C <1.5 mmol/L.

Clinical analysis of acute myocardial infarction caused by coronary embolism.

BACKGROUND: This study aims to investigate the clinical and angiographic features in patients with acute myocardial infarction (AMI) induced by coronary artery embolism. METHODS: Clinical data of five patients with AMI induced by coronary artery embolism were analyzed retrospectively. RESULTS: One patient had left atrial myxoma, one patient had non-valvular atrial fibrillation, and three patients had rheumatic heart disease. Furthermore, one patient had mitral mechanical valve prostheses, two patients had atrial fibrillation. Coronary angiography showed the absence of significant atherosclerostic lesions in the coronary arteries except infarct related artery in five patients. Angiography suggested the presence of IRA occlusion caused by embolism. CONCLUSIONS: The status for AMI due to coronary artery embolism usually expresses embolic material originating from the left heart chambers. Rheumatic heart disease and atrial fibrillation are the common reasons for coronary artery embolism. Coronary artery occlusion is the common performance in the results of primary coronary artery angiography. Sometimes it expresses visible signs of embolism.