In order to assess the clinical manifestations and electrocardiogram (ECG) characteristics of Chinese long QT syndrome (LQTS) patients and describe the phenotype-genotype correlation, the subjects from 5 congenital LQTS families underwent clinical detailed examination including resting body surface ECG. QT interval and transmural dispersion of repolarization (TDR) were manually measured. Five families were genotyped by linkage analysis (polymerase chain reacting-short tandem repeat, PCR-STR). The phenotype-genotype correlation was analyzed. Four families were LQT2, 1 family was LQT3. Twenty-eight gene carriers were (14 males and 14 females) identified from 5 families. The mean QTc and TDRc were 0.56 +/- 0.04 s (range 0.42 to 0.63) and 0.16 +/- 0.04 s (range 0.09 to 0.24) respectively. 35.7% (10/28) had normal to borderline QTc (< or = 0.460 s). There was significant difference in QTc and TDRc between the patients with symptomatic LQTS and those with asymptomatic LQTS, and there was significant difference in TDRc between the asymptomatic patients and normal people also. A history of cardiac events was present in 50% (14/28), including 9 with syncope, 2 with sudden death (SD) and occurred in the absence of beta-blocker. Three SDs occurred prior to the diagnosis of LQTS and had no ECG record. Two out of 5 SDs (40%) occurred as the first symptom. Typical LQT2 T wave pattern were found in 40% (6/15) of all affected members. The appearing-normal T wave was found in one LQT3 family. Low penetrance of QTc and symptoms resulted in diagnostic challenge. ECG patterns and repolarization parameters may be used to predict the genotype in most families. Genetic test is very important for identification of gene carriers.
Arrhythmia/etiology ; Arrhythmia/genetics ; Asian Continental Ancestry Group ; Electrocardiography ; Genotype ; Long QT Syndrome/complications ; Long QT Syndrome/congenital ; Long QT Syndrome/*genetics ; Pedigree ; *Phenotype

A growing body of evidence, including studies using genetically engineered mouse models, has shown that Ca2+ cycling and Ca2+ -dependent signaling pathways play a pivotal role in cardiac hypertrophy and heart failure. In addition, recent studies identified that mutations of the genes encoding sarcoplasmic reticulum (SR) proteins cause human cardiomyopathies and lethal ventricular arrhythmias. The regulation of Ca2+ homeostasis via the SR proteins may have potential therapeutic value for heart diseases such as cardiomyopathy, heart failure and arrhythmias.
Animals ; Animals, Genetically Modified ; Arrhythmia/genetics ; Calcium/*metabolism ; Calcium Channels/genetics/*physiology ; Calcium-Binding Proteins/genetics/*physiology ; Cardiac Output, Low/genetics ; Cardiomyopathies/genetics ; Heart Diseases/*etiology/genetics/metabolism ; Humans ; Mutation/genetics ; Research Support, Non-U.S. Gov't ; Sarcoplasmic Reticulum/metabolism

Translational medicine is a novel concept about combination of basic research and clinical application. The aim of translational medicine is to realize the translation of basic research into clinical practice. microRNAs (miRNAs) are non-coding single-stranded RNAs with 21-25 nucleotides in length as newly discovered factors in regulating gene expression. Recently, the key regulatory role of miRNA in the cardiovascular system has been elucidated and amount of remarkable results has been achieved, particularly in the regulation of cardiac arrhythmias. A series of studies demonstrate that miRNAs are involved in the regulation of expression of a variety of proteins associated with cardiac electrical activity, and are the potential targets of occurrence of cardiac arrhythmias and anti-arrhythmic drugs. miRNAs as a therapeutic target regulate the stability of mRNAs of target genes or play an inhibitory role in the translation process. Stability of the corresponding miRNA expression levels in the target organ may be a new approach for the disease therapy. Regarding the dysfunction of miRNA, we employed miRNA re-expression strategy and anti-miRNA strategy to correct target protein function and provide a new entry for the therapy of arrhythmia. With the technology of miRNA mimics and antagomirs, miRNAs are expected to treat various cardiovascular diseases and will provide a fresh impetus to achieve transform medicine.
Animals ; Anti-Arrhythmia Agents ; therapeutic use ; Arrhythmias, Cardiac ; enzymology ; therapy ; Gene Expression Regulation ; Humans ; Ion Channels ; metabolism ; MicroRNAs ; antagonists & inhibitors ; genetics ; metabolism ; physiology ; RNA Interference ; Translational Medical Research

OBJECTIVETo discuss the role of calcium-overloading in initiation and maintenance of atrial fibrillation (AF).

METHODSThe right atrial appendages were obtained from 14 patients with AF and 12 patients with sinus rhythm. The mRNA expression of proteins influencing the calcium homeostasis was measured by semi-quantitative reverse transcription-polymerase chain reaction (RT-PCR) and normalized to the mRNA level of glyceraldehyde-3- phosphate dehydrogenase. The left atrial diameter (LAD), mitral valvular area (MVOA), and systolic pulmonary arterial pressure were obtained by echocardiography before surgery.

RESULTSCompared to sinus rhythm group, the mRNA levels of L-type calcium channel alc, sarcoplasmic reticulum (SR), calcium adenosine triphosphatase (Ca2+ -ATPase), and ryanodine receptor type-2 (R(Y) R2) were significantly decreased (P < 0.01); the mRNA level of inositol triphosphate receptor type-1 (IP3R1) was significantly increased (P < 0.05). No changes in the mRNA expression of phospholamban and calsequestrin were observed between two groups (P > 0.05). Correlations were found between MVOA and mRNA levels of LVDC-Calc, SR Ca2+ -ATPase (r = 0.719, P = 0.004; r = 0.625, P = 0.017). The mRNA level of SR Ca2+ -ATPase was negatively correlated with LAD (r = -0.573, P = 0.032).

CONCLUSIONSCalcium loading may be responsible for the occurrence and maintenance of AF, and abnormal regulation in the mRNA expression may be the molecular mechanism of intracellular Ca2+ overload. The progressive nature of AF involves structural change.

Arrhythmia, Sinus ; metabolism ; Atrial Fibrillation ; metabolism ; pathology ; Calcium ; metabolism ; Calcium Channels ; biosynthesis ; genetics ; Calcium-Binding Proteins ; biosynthesis ; genetics ; Calcium-Transporting ATPases ; biosynthesis ; genetics ; Chronic Disease ; Heart Atria ; metabolism ; pathology ; Humans ; Mitral Valve ; pathology ; Myocardium ; metabolism ; RNA, Messenger ; biosynthesis

Rapidly activating component of delayed rectifier potassium current (I(Kr)) plays a key role in the repolarization phase of cardiac action potential. Human ether-a-go-go-related gene (HERG) encodes the alpha subunit of this potassium channel. Mutations of HERG gene induce genetic long QT syndrome (LQTS). Furthermore, I(Kr)/HERG is the target of some drugs which may cause cardiac QT interval prolongation. Some other drugs with different chemical structures also may block the channel and prolong QT interval, which even developed into acquired arrhythmias. This review summarized the recent progress of structure, gating mechanisms and functions of I(Kr)/HERG channel, I(Kr)/HERG related arrhythmias, interaction between K+ channel and drugs, and strategies of grading-up the I(Kr)/HERG target.
Anti-Arrhythmia Agents ; adverse effects ; pharmacology ; therapeutic use ; Arrhythmias, Cardiac ; drug therapy ; metabolism ; Ether-A-Go-Go Potassium Channels ; antagonists & inhibitors ; chemistry ; genetics ; metabolism ; Humans ; Ion Channel Gating ; Long QT Syndrome ; drug therapy ; etiology ; genetics ; metabolism ; Mutation ; Potassium Channel Blockers ; pharmacology

OBJECTIVERecent studies have shown that cytokines TNF-alpha and IL-6 play important roles in myocardial injury or dysfunction. Transcription nuclear factor (NF-kappa B) have been implicated in the regulation of a variety of cytokines in response to cellular defense. The authors observed the activity of NF-kappa B and cytokines TNF-alpha, IL-6 mRNA expression in myocardium to further investigate the mechanism of myocardial injury caused by infectious pneumonia. The therapeutic effect of exogenous adenosine was also studied by observing the influence on NF-kappa B and cytokines.

METHODSThirty rats were divided into three experimental groups at random, each group had 10 rats. The model of pneumonia was induced by the injection of Staphylococcus aureus into the trachea of rats. Adenosine-treated rats were given daily slow intravenous injection of adenosine at a dose of 150 microg/kg.min for 3 days from the second day. All rats were killed on the fifth day. Myocardial tissues were preserved in liquid nitrogen for examination. Pathological examination of myocardium was done and TNF-alpha and IL-6 mRNA expression was detected by reverse transcription polymerase chain reaction (RT-PCR). NF-kappa B activity was measured by electrophoretic mobility shift assay (EMSA).

RESULTS(1) The myocardium in pneumonia group showed significant pathological lesion when compared with control group (P < 0.01). The pathological lesion of myocardium in adenosine-treated group significantly decreased when compared to pneumonia group (P < 0.05). (2) Significant increase of TNF-alpha and IL-6 mRNA expression was observed in myocardium of pneumonic rats when compared with control group (2.27 +/- 0.27 vs. 1.05 +/- 0.16; 1.89 +/- 0.31 vs. 1.12 +/- 0.25: P < 0.01, respectively). NF-kappa B activity of myocardium in pneumonia group was significantly higher than that in control group (13,033 +/- 1286 vs. 383 +/- 15: P < 0.01). (3) TNF-alpha and IL-6 mRNA expression was significantly decreased in adenosine-treated group when compared with pneumonia group (1.25 +/- 0.18 vs. 2.27; 1.31 +/- 0.25 vs. 1.89 +/- 0.31, P < 0.01, respectively). Comparing to that in pneumonia group, NF-kappa B activity of myocardium in adenosine-treated group was significantly decreased (4 487 +/- 562 vs. 13033 +/- 1286, P < 0.01), but it was still significantly higher than that in control group (4487 +/- 562 vs.383 +/- 15, P < 0.01).

CONCLUSIONSIncreased activity of NF-kappa B and subsequent upregulation of TNF-alpha and IL-6 mRNA expression probably play a pivotal role in the mechanism of myocardial injury in rats with pneumonia. Exogenous adenosine can inhibit inflammatory change by lowering NF-kappa B activity and subsequent down-regulation of TNF-alpha and IL-6 expression. Our findings provide novel therapeutic evidence of adenosine in myocardial injury induced by pneumonia in clinic.

Adenosine ; pharmacology ; Animals ; Anti-Arrhythmia Agents ; pharmacology ; Cytokines ; genetics ; metabolism ; Disease Models, Animal ; Electrophoretic Mobility Shift Assay ; Female ; Gene Expression ; drug effects ; Interleukin-6 ; genetics ; metabolism ; Male ; Myocardium ; metabolism ; NF-kappa B ; genetics ; metabolism ; Pneumonia, Staphylococcal ; drug therapy ; genetics ; metabolism ; RNA, Messenger ; genetics ; metabolism ; Random Allocation ; Rats ; Rats, Sprague-Dawley ; Reverse Transcriptase Polymerase Chain Reaction ; Tumor Necrosis Factor-alpha ; genetics ; metabolism

Because HERG potassium channel has important effects on both proarrhythmia and antiarrhythmia, we use immunofluorescence and Western blotting methods to detect the expression of HERG channel of HERG-HEK cells in different concentrations of matrine, oxymatrine and resveratrol. The findings showed that both matrine (1 micromol x L(-1) ) and oxymatrine ( 1micromol x L (-1) ) increased HERG channel expression ( n = 5, P < 0. 05 ) , while matrine (100 micromol x L(-1) ) decreased HERG channel expression ( n = 5, P < 0. 05), resveratrol didn't affect HERG channel expression. In conclusion, different concentrations of matrine and oxymatrine affect HERG channel expression, while there is no relationship between resveratrol and HERG channel expression. It provides a theoretical support for the safety and mechanism of anti-arrhythmic drugs.
Alkaloids ; pharmacology ; Anti-Arrhythmia Agents ; pharmacology ; Blotting, Western ; Cell Line ; Dose-Response Relationship, Drug ; ERG1 Potassium Channel ; Ether-A-Go-Go Potassium Channels ; genetics ; metabolism ; physiology ; Fluorescent Antibody Technique ; Humans ; Membrane Potentials ; drug effects ; Patch-Clamp Techniques ; Plants, Medicinal ; chemistry ; Quinolizines ; pharmacology ; Sophora ; chemistry ; Stilbenes ; pharmacology

OBJECTIVESTo investigate the effect of HOE642 on cardiac myocyte apoptosis of the heterotopic heart transplantation of rat non heart-beating donors.

METHODSTotally 112 male Sprague-Dawley rats were randomly divided into 7 groups (n=16 in each group) C, the control group (normal hearts); S10, S30, and S45 (groups of transplanted hearts after 10, 30, and 45 minutes of asystole); and SH10, SH30, and SH45 (groups of transplanted hearts after 10, 30, and 45 minutes of asystole and infused with HOE642). After rata in the experimental groups were killed by warm ischemia the donators of the S10, S30 and S45 groups were infused with 5TH-1 for 30 minutes, and the dead rats in group SH10, SH30, and SH4 were infused with STH-1 and HOE642 (20 micromol/L) for 30 minutes. Heterotopic heart transplantation were processed by the method of neck Cuff. The heart specimens of S10, SH10, S30, and SH30 groups were taken after 48 hours of transplantation, and the heart specimens of S45 and SH45 groups were taken immediately after transplantation. Then apoptotic myocytes were detected with terminal deoxynucleotide transferase-mediated deoxyuridine-biotin nick end labeling method and the expressions of Bcl-2, Bax, and Caspase-3 proteins were detected by immunohistochemistry.

RESULTSThe rats were discerned death when cardiac electric wave vanished after 9-11 minutes of bloodletting by transsection of abdominal aorta. The number of positive cardiac muscle cells in S10 and S30 groups were significantly larger than those in group SH10 and SH30 (P < 0.05). The levels of Bcl-2 protein expression in S10 and S30 groups were significantly lower than those in SH10 and SH30 groups (P < 0.05). The levels of Bax and Caspase-3 protein expression were significantly higher than those in SH10 and SH30 groups (P < 0.05).

CONCLUSIONSThe rat model of a heterotopic heart transplantation on the cervical part is a convenient animal model for cardiac muscle protection. HOE642 can suppress rat cardiac muscle cells apoptosis (within 30 min) after death caused by warm ischemia.

Animals ; Anti-Arrhythmia Agents ; pharmacology ; Apoptosis ; drug effects ; Gene Expression ; drug effects ; Guanidines ; pharmacology ; Heart ; physiopathology ; Heart Transplantation ; Male ; Myocardial Contraction ; drug effects ; Myocytes, Cardiac ; cytology ; drug effects ; metabolism ; Proto-Oncogene Proteins c-bcl-2 ; genetics ; metabolism ; Random Allocation ; Rats ; Rats, Sprague-Dawley ; Sulfones ; pharmacology

OBJECTIVETo investigate the prophylactic and therapeutic effect of oxymatrine on experimental liver fibrosis and to reveal its mechanism.

METHODSBy establishing D-galactosamine-induced rat liver fibrosis model, we observed the effect of oxymatrine on serum and tissue biochemical indexes, content of liver hydroxyline, expression of TGF?1 mRNA and changes of tissue pathology.

RESULTSThere was a decline of liver hydroxyline and serum AST and ALT in oxymatrine group compared to those of the D-GalN group. The hydroxyline content in oxymatrine pretreatment group was (0.50 0.11)mug/mg compared with (0.99 0.14)mug/mg in D-GalN group (t=8.366, P<0.01). The content in oxymatrine treatment group was (0.44 0.04)mug/mg compared with 0.70 0.06 in D-GalN group (t=9.839, P<0.01). The SOD activity was (149.81 15.28) NU/mg in oxymatrine pretreatment group and (95.22 16.33) NU/mg in the model group (t=7.309, P<0.01); (157.68 19.54) NU/mg in the treatment group compared with (119.88 14.94) NU/mg in the model group (t=4.348, P<0.01). MDA in the pretreatment group was (2.06 0.17) nmol/mg, lower than (4.57 0.37) nmol/mg in the model group (t=17.529, P<0.01). In the treatment group, it was (1.76 0.24)nmol/mg, lower than (3.10 0.17) nmol/mg in the model group (t=12.697, P<0.01). TGF?1 mRNA reduced in the pretreatment and treatment groups as compared with that in the model group (0.21 0.01 vs 0.50 0.01, t=48.665, P<0.01; 0.18 0.02 vs 0.38 0.01, t=22.464, P<0.01). Electron microscopy showed that oxymatrine group had milder hepatocyte degeneration and less fibrosis accumulation than did the model group. Microscopy revealed wide septa expansion from the portal area to the central venous, piecemeal and confluent necrosis and pseudo-nodular formation in part of the lobular in the model group. While in oxymatrine group these lesions were much improved.

CONCLUSIONSOxymatrine shows prophylactic and therapeutic effect in D-galactosamine induced rat liver fibrosis. This is partly by protecting hepatocyte and suppressing fibrosis accumulation through anti-lipoperoxidation.

Alkaloids ; therapeutic use ; Animals ; Anti-Arrhythmia Agents ; therapeutic use ; Calcium Hydroxide ; metabolism ; Chemoprevention ; Disease Models, Animal ; Galactosamine ; Liver Cirrhosis ; chemically induced ; drug therapy ; metabolism ; pathology ; prevention & control ; Liver Function Tests ; Male ; Quinolizines ; RNA, Messenger ; metabolism ; Rats ; Rats, Wistar ; Superoxide Dismutase ; metabolism ; Transforming Growth Factor beta ; genetics ; metabolism

OBJECTIVETo investigate the molecular mechanism of human ether-a-go-go-related gene (HERG) potassium channels regulated by protein kinase A (PKA) in a human cell line.

METHODSHERG channels were stably expressed in human embryonic kidney (HEK) 293 cells, and currents were measured with the patch clamp technique. The direct phosphorylation of HERG channel proteins expressed heterologously in Xenopus laevis oocytes was examined by (32)P labeling and immunoprecipitation with an anti-HERG antibody.

RESULTSElevation of the intracellular cAMP-concentration by incubation with the adenylate cyclase activator, forskolin (10 micromol/L), and the broad range phosphodiesterase inhibitor, IBMX (100 micromol/L), caused a HERG tail current reduction of 83.2%. In addition, direct application of the membrane permeable cAMP analog, 8-Br-cAMP (500 micromol/L), reduced the tail current amplitude by 29.3%. Intracellular application of the catalytic subunit of protein kinase A (200 U/ml) led to a tail current decrease by 56.9% and shifted the activation curve by 15.4 mV towards more positive potentials. HERG WT proteins showed two phosphorylated bands, an upper band with a molecular mass of approximately 155 kDa and a lower band with a molecular mass of approximately 135 kDa, indicating that both the core- and the fully glycosylated forms of the protein were phosphorylated.

CONCLUSIONSPKA-mediated phosphorylation of HERG channels causes current reduction in a human cell line. The coupling between the repolarizing cardiac HERG potassium current and the protein kinase A system could contribute to arrhythmogenesis under pathophysiological conditions.

1-Methyl-3-isobutylxanthine ; pharmacology ; 8-Bromo Cyclic Adenosine Monophosphate ; pharmacology ; Adenylyl Cyclases ; metabolism ; Animals ; Anti-Arrhythmia Agents ; pharmacology ; Cation Transport Proteins ; Cell Line ; Colforsin ; pharmacology ; Cyclic AMP ; metabolism ; Cyclic AMP-Dependent Protein Kinases ; metabolism ; DNA-Binding Proteins ; ERG1 Potassium Channel ; Enzyme Activation ; drug effects ; Ether-A-Go-Go Potassium Channels ; Female ; Humans ; Membrane Potentials ; drug effects ; Microinjections ; Oocytes ; Patch-Clamp Techniques ; Phenethylamines ; pharmacology ; Phosphodiesterase Inhibitors ; pharmacology ; Phosphoric Diester Hydrolases ; drug effects ; metabolism ; Phosphorylation ; Potassium Channels ; genetics ; metabolism ; physiology ; Potassium Channels, Voltage-Gated ; RNA, Complementary ; administration & dosage ; genetics ; Sulfonamides ; pharmacology ; Trans-Activators ; Transcriptional Regulator ERG ; Xenopus laevis