The aim of the present study was to investigate the effects of adiponectin (APN) on the expression of T-cadherin in cultured Sprague-Dawley (SD) rat cardiomyocytes injured by hypoxia/reoxygenation (H/R). Primary myocardial cells from neonatal rats were obtained by enzymatic digestion. The cells were divided into control group, H/R group and H/R+APN (3, 10, 20 and 30 μg/mL) groups. The H/R group was incubated in anoxic environment (anoxic solution saturated with high concentration N2) for 3 h, and then in the reoxygenation environment (the reoxygenation solution saturated with pure oxygen) for 1 h. The H/R+APN group was pretreated with different concentrations of APN for 24 h prior to the initiation of H/R. The content of lactate dehydrogenase (LDH) was measured by chemistry chromatometry. Cellular apoptosis was analyzed by flow cytometry and terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL). The expression of T-cadherin was detected by RT-PCR and Western blotting. The results showed that, compared with control group, the apoptotic rate and release of LDH were significantly increased in the H/R group, whereas the expressions of T-cad mRNA and protein were decreased. Pretreating with APN significantly and dose-dependently decreased apoptotic rate and LDH release, and up-regulated T-cad mRNA and protein level in rat neonatal cardiomyocytes under H/R conditions. These results suggest that APN may protect cardiomyocytes against H/R-induced injury by up-regulating H/R-decreased T-cad expression.
Adiponectin ; pharmacology ; Animals ; Apoptosis ; Cadherins ; metabolism ; Cell Hypoxia ; L-Lactate Dehydrogenase ; metabolism ; Myocytes, Cardiac ; drug effects ; metabolism ; pathology ; Oxygen ; adverse effects ; Rats ; Rats, Sprague-Dawley ; Up-Regulation

OBJECTIVETo investigate the mechanism of enhanced large conductance calcium-activated potassium channel currents (BK) in coronary smooth muscle cells (SMCs) by docosahexaenoic acid (DHA).

METHODSCoronary SMCs were isolated by enzyme digestion. Potassium channels in coronary SMCs were identified by applications of different potassium blockers. Effects of DHA and its metabolite 16, 17-epoxydocosapentaenoic acid (16, 17-EDP) on BK channels in the absence and presence of cytochrome P450 epoxygenase inhibitor SKF525A were studied by patch clamp in whole-cell configuration.

RESULTSBK channels were widely distributed in SMCs, and BK currents in normal SMCs accounted for (64.2 ± 2.7)% of total potassium currents (n = 20). DHA could activate BK channels, and its 50% effective concentration (EC(50)) was (0.23 ± 0.03) µmol/L, however, the effect of DHA on BK channels was abolished after SMCs were incubated with cytochrome P450 epoxygenase inhibitor SKF525A. 16, 17-EDP, a metabolite of DHA, could reproduce the effects of DHA on BK channels, and its EC(50) was (19.7 ± 2.8) nmol/L.

CONCLUSIONDHA and metabolites can activate BK channels and dilate coronary arteries through activating cytochrome P450 epoxygenase pathway.

Animals ; Coronary Vessels ; cytology ; drug effects ; metabolism ; Cytochrome P-450 Enzyme Inhibitors ; Docosahexaenoic Acids ; pharmacology ; Fatty Acids, Unsaturated ; pharmacology ; Large-Conductance Calcium-Activated Potassium Channels ; metabolism ; Muscle, Smooth, Vascular ; drug effects ; metabolism ; Myocytes, Smooth Muscle ; drug effects ; metabolism ; Proadifen ; pharmacology ; Rats ; Rats, Sprague-Dawley

BACKGROUNDThere is a paucity of studies investigating the clinical and biochemical characteristics of pain in chronic heart failure (CHF) patients. This study aimed to determine the clinical and biochemical characteristics and outcomes in Chinese patients with CHF and symptoms of pain.

METHODSSociodemographics, serum levels of creatinine, NT-proBNP, high-sensitivity C-reactive protein (hs-CRP), tumor necrosis factor (TNF)-α, interleukin (IL)-6 and IL-10, and two-dimensional echocardiographic left ventricular ejection fraction (LVEF) were determined in 305 patients with CHF. A questionnaire packet including the Brief Pain Inventory (BPI) and the Minnesota Living with Heart Failure Questionnaire (MLHFQ) was used to assess the degree of pain rated on a 0 - 10 scale and the quality of life (QOL). A six-minute walking test was performed during routine clinic visits. Major adverse cardiac events (MACE) were recorded; including all-cause or cardiac mortality and rehospitalization because of myocardial infarction, worsening heart failure or stroke at follow-up.

RESULTSPain occurred in 25.6% of CHF patients, and was more common when the New York Heart Association (NYHA) functional class was worse. More patients with pain were female in gender, and had more co-morbidities, lower LVEF, and shorter distance during the 6-minute walking test. Despite similar serum levels of creatinine, N-terminal prohormone of brain natriuretic peptide (NT-proBNP), IL-6 and IL-10, the TNF-α levels were higher and MLHFQ scores were greater in CHF patients with pain. At follow-up, CHF patients with moderate to severe pain (≥ 4 scale) had higher rates of all-cause and cardiac mortality and rehospitalization because of myocardial infarction, worsening heart failure or stroke. Multivariate regression analysis revealed that the presence of pain was an independent risk factor for MACE and reduced QOL in CHF patients.

CONCLUSIONSPain occurs in all stages of the CHF trajectory, and its incidence increases as clinical functional status is worsened. The presence of pain exerts a negative impact on clinical outcome and QOL in patients with CHF.

C-Reactive Protein ; metabolism ; Echocardiography ; Female ; Heart Failure ; metabolism ; physiopathology ; Humans ; Interleukin-10 ; blood ; Interleukin-6 ; blood ; Male ; Pain ; metabolism ; physiopathology ; Tumor Necrosis Factor-alpha ; blood

BACKGROUNDPotentially lethal ventricular arrhythmias (PLVAs) occur frequently in survivors after acute myocardial infarction and are increasingly recognized in other forms of structural heart diseases. This study investigated the prevalence and prognostic significance of PLVAs in patients with chronic heart failure (CHF).

METHODSData concerning demographics, etiology of heart failure, NYHA functional class, biochemical variables, electrocardiographic and echocardiographic findings, and medical treatments were collected by reviewing hospital medical records from 1080 patients with NYHA II-IV and a left ventricular (LV) ejection fraction ≤ 45%. PLVAs were defined as multi-focal ventricular ectopy (> 30 beats/h on Holter monitoring), bursts of ventricular premature beats, and nonsustained ventricular tachycardia. All-cause mortality, sudden death, and rehospitalization due to worsening heart failure, or cardiac transplantation during 5-year follow-up after discharge were recorded.

RESULTSThe occurrence rate of PLVAs in CHF was 30.2%, and increased with age; 23.4% in patients < 45 years old, 27.8% in those between 45 - 65 years old, and 33.5% in patients > 65 years old (P = 0.033). Patients with PLVAs had larger LV size and lower ejection fraction (both P < 0.01) and higher all-cause mortality (P = 0.014) during 5-year follow-up than those without PLVAs. Age (OR 1.041, 95%CI 1.004 - 1.079, P = 0.03) and LV end-diastolic dimension (OR 1.068, 95%CI 1.013 - 1.126, P = 0.015) independently predicted the occurrence of PLVAs. And PLVA was an independent factor for all-cause mortality (RR 1.702, 95%CI 1.017 - 2.848, P = 0.031) and sudden death (RR 1.937, 95%CI 1.068 - 3.516, P = 0.030) in patients with CHF.

CONCLUSIONPLVAs are common and exert a negative impact on long-term clinical outcome in patients with CHF.

Adult ; Aged ; Arrhythmias, Cardiac ; mortality ; physiopathology ; Electrocardiography ; Female ; Heart Failure ; physiopathology ; Humans ; Male ; Middle Aged ; Regression Analysis

BACKGROUNDDiabetes mellitus is associated with coronary dysfunction, contributing to a 2- to 4-fold increase in the risk of coronary heart diseases. The mechanisms by which diabetes induces vasculopathy involve endothelial-dependent and -independent vascular dysfunction in both type 1 and type 2 diabetes mellitus. The purpose of this study is to determine the role of vascular large conductance Ca(2+)-activated K(+) (BK) channel activities in coronary dysfunction in streptozotocin-induced diabetic rats.

METHODSUsing videomicroscopy, immunoblotting, fluorescent assay and patch clamp techniques, we investigated the coronary BK channel activities and BK channel-mediated coronary vasoreactivity in streptozotocin-induced diabetic rats.

RESULTSBK currents (defined as the iberiotoxin-sensitive K(+) component) contribute (65 ± 4)% of the total K(+) currents in freshly isolated coronary smooth muscle cells and > 50% of the contraction of the inner diameter of coronary arteries from normal rats. However, BK current density is remarkably reduced in coronary smooth muscle cells of streptozotocin-induced diabetic rats, leading to an increase in coronary artery tension. BK channel activity in response to free Ca(2+) is impaired in diabetic rats. Moreover, cytoplasmic application of DHS-1 (a specific BK channel b(1) subunit activator) robustly enhanced the open probability of BK channels in coronary smooth muscle cells of normal rats. In diabetic rats, the DHS-1 effect was diminished in the presence of 200 nmol/L Ca(2+) and was significantly attenuated in the presence of high free calcium concentration, i.e., 1 mmol/L Ca(2+). Immunoblotting experiments confirmed that there was a 2-fold decrease in BK-b(1) protein expression in diabetic vessels, without altering the BK channel α-subunit expression. Although the cytosolic Ca(2+) concentration of coronary arterial smooth muscle cells was increased from (103 ± 23) nmol/L (n = 5) of control rats to (193 ± 22) nmol/L (n = 6, P < 0.05) of STZ-induced diabetic rats, reduced BK-b(1) expression made these channels less sensitive to intracellular Ca(2+), which in turn led to enhanced smooth muscle contraction.

CONCLUSIONSOur results indicated that BK channels are the key determinant of coronary arterial tone. Impaired BK channel function in diabetes mellitus is associated with down-regulation of BK-b(1) expression and reduction of the b(1)-mediated BK channel activation in diabetic vessels.

Animals ; Blotting, Western ; Coronary Vessels ; metabolism ; Diabetes Mellitus, Experimental ; metabolism ; physiopathology ; Diabetes Mellitus, Type 1 ; metabolism ; physiopathology ; Electrophysiology ; Large-Conductance Calcium-Activated Potassium Channels ; metabolism ; Male ; Muscle, Smooth, Vascular ; metabolism ; Rats ; Rats, Sprague-Dawley