Long-term ethanol exposure inhibits glucose transporter 4 expression via an AMPK-dependent pathway in adipocytes.

AIM: The roles of AMP-activated protein kinase (AMPK) and myocyte enhancer factor 2 isoforms (MEF2A, D) as mediators of the effects of ethanol on glucose transporter 4 (GLUT4) expression are unclear. We studied the effects of ethanol in adipocytes in vivo and in vitro. METHODS: Thirty-six male Wistar rats were divided into three groups and given ethanol in a single daily dose of 0, 0.5, or 5 g/kg for 22 weeks. The expression of AMPK, MEF2 isoforms A and D, and GLUT4 was measured and compared in the three groups. The existence of the AMPK/MEF2/GLUT4 pathway in adipocytes and the effects of ethanol on this pathway were studied in (a) epididymal adipose tissue from six male Wistar rats subcutaneously injected with 5-aminoimidazole-4-carboxamide ribonucleoside (AICAR, an AMPK activator) or with 0.9% NaCl (control); and (b) isolated rat and human adipocytes treated with or without ethanol, AICAR, and compound C (a selective AMPK inhibitor). Expression of AMPK, MEF2, and GLUT4 was measured by RT-PCR and Western blotting. RESULTS: (1) Long-term ethanol exposure decreased activated AMPK, MEF2A, MEF2D, and GLUT4 expression in rat adipose tissue. (2) In rat and human adipocytes, AICAR-induced AMPK activation, with subsequent elevation of MEF2 and GLUT4 expression, was inhibited by compound C. (3) In vitro ethanol-treatment suppressed the AMPK/MEF2/GLUT4 pathway. CONCLUSION: The AMPK/MEF2/GLUT4 pathway exists in both rat and human adipocytes, and activated AMPK may positively regulate MEF2 and GLUT4 expression. Ethanol inhibition of this pathway leads to decreased GLUT4 expression, thus reducing insulin sensitivity and glucose tolerance.

[Recombinant adeno-associated virus mediated RNA interference of angiogenin expression inhibits cell growth of human lung adenocarcinoma].

OBJECTIVE: To study the inhibition of angiogenin (ANG) expression in human lung squamous cancer cell strain-A549 through adeno-associated virus (AAV)-mediated RNA-interference, and therefore to observe its effect on the growth of cancer cells and tumor formation. METHODS: Recombinant AAV expressing H1-promoter-induced small-interference- RNA (siRNA) targeting ANG (AAV-shANG) was constructed, and then transfected into A549 cells. A549 cells and cells transfected with AAV-Null were used as the control groups. The effects of the reduced expression of ANG by RNAi from AAV-shANG on the growth, formation, reproduction, apoptosis, and microvessel-density of the carcinoma were observed. RESULTS: In vitro experiment showed that AAV-shANG was constructed successfully, There was an significant decrease in the expression of ANG protein 72 h after transfection, compared with the normal A459 cells and AAV-Null cells (P < 0.01). Cell cycle analysis showed that the proliferation index (PI) of normal A549 cells, AAV-Null cells and AAVshANG cells were 0.32 +/- 0.29, 0.35 +/- 0.38 and 0.31 +/- 0.43, respectively. There was no statistic difference in the PIs among the 3 groups (P > 0.05). In vivo experiment using thymus-defect mice showed that, there was an remarkable reduction in the mass and volume of tumors in AAV-shANG transfected group, compared to the control groups. Microvessel-density was 9.4 +/- 1.5, 9.8 +/- 2.1 and 5.7 +/- 1.9, respectively in the 3 groups, a statistic difference among the AAV-shANG-transfected group, the normal A549 group and the AAV-Null transfected group. The percentages of apoptotic cells in each group were (7.7 +/- 3.1)%, (8.5 +/- 5.4)%, (17.1 +/- 8.6)%, respectively, the experimental group being higher than those of the control groups. Positive rates of PCNA were (84.8 +/- 9.7)%, (85.8 +/- 9.8)%, and (70.4 +/- 10.1)%, respectively, the AAV-shANG transfected cancer cells showing a lower PCNA index than the control groups. CONCLUSION: AAV-mediated expression of siRNA could reduce the expression of ANG in cancer cells, significantly enough to inhibit cell proliferation, promote cell apoptosis and inhibit tumor growth.

[Effects of Xuefu Zhuyu Capsule on endothelin-1 release in myocardium and vascular endothelium and nitric oxide/nitric oxide synthase system of swines after acute myocardial infarction and reperfusion].

OBJECTIVE: To observe the effects of Xuefu Zhuyu Capsule (XFZYC), a compound traditional Chinese herbal medicine, on endothelin-1 (ET-1) release in myocardium and vascular endothelium and nitric oxide (NO)/nitric oxide synthase (NOS) system of swines after acute myocardial infarction (AMI) and reperfusion, and to explore the action mechanisms of XFZYC in improving the endothelium function. METHODS: Forty-five Yorkshire swines were randomized into 3 groups: sham-operated group, untreated group and XFZYC-treated group. A Yorkshire swine model of reperfusion in AMI was established by ligation of left anterior descending coronary artery for 90 min followed by 2 h relaxation. The content of serum ET-1 and NO was measured by radioimmunoassay before and after AMI and after reperfusion, respectively. Twenty-four hours after operation, all Yorkshire swines underwent diagnostic coronary angiography to delineate coronary arteries. The expressions of ET-1 and endothelial nitric oxide synthase (eNOS) in myocardial tissue of ischemic area were quantified with Western blotting. Microvessel density of the implanting sites was assessed by using HE staining. RESULTS: Compared with the untreated group, the levels of serum ET-1 after AMI and reperfusion were significantly decreased in XFZYC-treated group (P<0.01), while the NO levels after AMI and reperfusion in XFZYC-treated group were significantly increased (P<0.01). There was no significant difference in diagnostic coronary angiography between XFZYC-treated group and untreated group (P=0.253). Western blotting showed that the level of ET-1 in ischemic area in XFZYC-treated group was lower than that in the untreated group (P<0.01), while the eNOS protein expression in XFZYC-treated group was higher than that in the untreated group (P<0.01). The results of HE staining and microvessel density analysis of the implanting sites all showed that the degree of telangiectasis was reduced, the cardiac muscle damage was improved, and the density of capillaries was increased obviously in XFZYC-treated group as compared with the untreated group. CONCLUSION: The endothelium injury may be one of the important mechanisms for no-reflow phenomenon. XFZYC may reduce the no-reflow by protecting endothelium cells.

[Prevalence of coronary artery disease in patients with rheumatic heart disease in China].

OBJECTIVE: To investigate the prevalence of coronary artery disease (CAD) and the atherosclerotic risk factors in the patients undergoing valvular surgery due to rheumatic heart disease. METHODS: Consecutive 651 patients with rheumatic heart disease aged > 40 who were scheduled for valve surgery underwent diagnostic coronary angiography to delineate coronary arteries. Significant coronary artery disease was considered to be present if one or more single coronary branches showed 50% or more luminal stenosis. Symptoms, such chest pain, were evaluated. Established risk factors for CAD, such as diabetes mellitus, systemic hypertension, smoking, and dyslipidemia were evaluated. Previous history of myocardial infarction and coronary artery bypass surgery was also recorded. RESULTS: Seventy-one patients (10.91%), 54 males and 17 females, were detected as with CAD. The mean age of the patients with CAD was (63 +/- 9), significantly higher than that of the patients with normal coronary arteries [(54 +/- 9), P < 0.01]. The atheromatous lesion mostly involved the left descending branch (38.12%), and 38 patients (53.52%) showed lesions in 2 or more branches. The prevalence rates of diabetes mellitus and hypertension in the CAD group were 32.39% and 29.58% respectively, both significantly higher than those in the non-CAD group (7.41% and 19.48% respectively; P < 0.01 and P = 0.047). The smoking rate of the CAD group was 36.62%, significantly higher than that of the non-CAD group (12.93%; P < 0.01). However, there were not significant differences in the prevalence rates of dyslipidemia and ECG ST-T changes between these 2 groups (both P > 0.05). No relation was found between the rheumatic disease and coronary disease distribution (P > 0.05). CONCLUSION: Coronary angiography should be performed in all patients clinically suspected with CAD, aged > 50 and the patients with angina and/or coronary risk factors in order to decrease the occurrence of operative complications.