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Dyslipidemia is an important risk factor of atherosclerotic cardiovascular disease (ASCVD). Statins delay the occurrence and development of ASCVD, and reduce the risk of cardiovascular events and death. Due to safety concerns, there exist insufficient use of lipid-lowering agents and a high withdrawal rate of the agents in the elderly. To promote the prevention and treatment of ASCVD, this expert consensus is issued and focuses on the management of dyslipidemia of Chinese elderly basing on the clinical evidence of the use of lipid-lowering drugs by the elderly, and the lipid management guidelines and expert consensus recommendations at home and abroad.
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Objective@#To analyze pre- and post-operation electrocardiograms (ECGs) features of patients underwent orthotopic heart transplantation (OHT), and provide evidences for identifying and analyzing post OHT ECGs.@*Methods@#Nine hundreds and ninty-eight pre- and post- OHT standard 12-leads ECGs from 110 consecutive patients, who underwent OHT in our hospital from May 2008 to May 2014, were analyzed.@*Results@#The mean heart rate(HR)was (86.9±16.4) beats per minute before OHT, and (100.0±0.4) beats per minute after OHT. P wave′s amplitude, duration, amplitude multiplied by duration of donor heart in lead Ⅱ were (0.124±0.069)mV, (111.1±17.2)ms, (14.34±9.51)mV·ms before OHT; (0.054±0.037)mV, (86.9±27.0)ms, (5.02±4.03)mV·ms at 1 month after OHT; (0.073±0.049)mV, (93.9±17.5) ms, (7.00±4.81)mV·ms at 6 years after OHT. ECGs rotation occurred in 83.64%(92/110) patients after OHT, and prevalence of clockwise rotation was 76.36%(84/110). Sinus tachycardia was evidenced in 99.09%(109/110) patients after OHT, and incomplete right bundle branch block was present in 60.91%(67/110) patients after OHT. Pseudo complete atrioventricular block mostly occurred at 2 days after OHT. Prevalence of double sinus rhythm was 27.95%(263/941) post OHT, 40% of them occurred between the 1st and the 2nd month post OHT; the atrial rate of recipient hearts was (104.0±10.2) beats per minucte between the 3rd and the 6th month post OHT, and was (95.3±4.2) beats per minucte between the 4th year and the 5th year. P wave′s amplitude, duration, amplitude multiplied by duration of recipient heart in lead Ⅱ were (0.066±0.055) mV, (52.8±34.7) ms, (4.67±4.95) mV·ms at 1 month after OHT, (0.043±0.040)mV, (44.4±40.5) ms , (3.11±3.61) mV·ms between the 1st year and 2nd year after OHT. The absolute value of P-wave(originating from the donor heart) terminal force in chest leads increased in 48.99%(461/941) patients post OHT, the P-wave terminal force of V1 , V2 and V3 were -0.044(-0.066, -0.028), -0.060(-0.087, -0.038), -0.035(-0.056, 0) mm·s. Notched P wave in chest leads was presented in 10.31%(97/941) patients post OHT. PR segment depression in chest leads occurred in 60.24%(100/166) patients between the 3rd month and the 6th month, the incidence of PR segment depression in V1 , V2 and V3 was 21.04%(198/941), 37.41%(352/941) and 28.69%(270/941), respectively.@*Conclusions@#OHT is related to significantly changed ECGs. The mean HR increased significantly after OHT, then decreased gradually after half a year to one year, but it was still higher than preoperative mean HR after five or six years; the P waves of donor heart were usually inconspicuous or small in first month after OHT, and they became bigger after 2 months, and their duration and amplitude then became relatively steady afterwards. ECGs rotation, especially the clockwise rotation, was common post OHT. A variety of arrhythmias originating from the donor heart including sinus tachycardia and incomplete right bundle branch block could be found. Pseudo complete atrioventricular block could also be found in the early phase after OHT. With the extension of time, the incidence of double sinus rhythm reduced gradually. The atrial rate and P wave of recipient heart presented with a tendency to become lower. The absolute value of P-waves(originating from the donor heart) terminal force in chest leads (mainly V1, V2 and V3) increased, notched P waves in chest leads (mainly V1, V2) and PR segments depression in chest leads (mainly V2, V3 and V4) also belong to typical post OHT ECGs features.
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Objective To investigate the effect of diuretics combined with the new class volume-removing drugs nesiritide and tolvaptan on refractory heart failure (RHF).Methods We collected 78 patients with RHF from cardiovascular ICU in our hos-pital,and patients were divided into combined volume-removing drugs treatment group (CVR group)and traditional diuretics com-bined with inotropic treatment group (control group).We observed the differences in the heart failure symptoms control rate and the average hospitalization days between the two groups.The difference in average urine volume and weight loss during hospitaliza-tion was observed.Results The heart failure symptoms were controlled and successful discharge in 89.7% of patients in CVR group,which was better than that in control group(71.8%).The corresponding rates of death or abandonment was decreased sig-nificantly in CVR group,and the average number of hospitalization days in CVR group was significantly shorter than that in control group(P <0.05).Meanwhile,the average daily urine volume and the weight loss decreased significantly in CVR group than those in control group(P <0.05).Conclusion The therapy strategy of combined volume-removing drugs can significantly improve the vol-ume removing and control rate of heart failure symptoms.
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Objective: To explore the relationship between expression of tumor necrosis factor-α( TNF-α) and electrophysiological heterogeneity in isolated heart tissues and isolated rat ventricular myocytes.The arrhythmogenic mechanisms of TNF-αwere further studied.Methods:Langendorff perfused heart tissues models were used to verify the arrhythmogenic effects of TNF-α.The monophasic action potentials( MAPs) of the endocardium and epicardium from the isolated heart tissues were recorded by elec-trophysiological experiments.The isolated rat ventricular myocytes were obtained by enzymatic dissociation.K+currents(Ito,IK1)were recorded by using whole cell patch clamp technique.Results: Compared to the control group, the difference in MAPD between endocardium and epicardium dramatically increased with TNF-α( P<0.05 ) .TNF-αcould cause MAP duration ( MAPD ) prolongation, and a single dose of TNF-αdifferentially affected the MAPs of endocardium and epicardium of isolated heart tissues.Compared to the control group,the K+currents(Ito,IK1)were dose-dependently decreased with TNF-αin rat ventricular myocytes(P<0.05).However, etanercept had no effects on the MAPD in the absence of TNF-α.Conclusion:TNF-α-induced heterogeneity of MAPD between the endo-cardium and epicardium may provide the substrate for the onset of ventricular arrhythmias during acute myocardial infarction.The effect might be associated with TNF-αcontribute to re-entrant ventricular arrhythmias which resulted from decreased K+currents(Ito,IK1).
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The antibody against AT1-EC2 plays a role in some kinds of inflammatory vascular diseases including malignant hypertension, preeclampsia, and renal-allograft rejection, but the detailed mechanisms remain unclear. In order to investigate the changes of NADPH oxidase and reactive oxygen species in the aorta in a mouse model which can produce AT1-EC2 antibody by active immunization with AT1-EC2 peptide, 15 mice were divided into three groups: control group, AT1-EC2-immunized group, and AT1-EC2-immunized and valsartan-treated group. In AT1-EC2-immunized group and AT1-EC2-immunized and valsartan-treated group, the mice were immunized by 50 μg peptide subcutaneously at multiple points for 4 times: 0, 5, 10, and 15 days after the experiment. In AT1-EC2-immunized and valsartan-treated group, valsartan was given at a dose of 100 mg/kg every day for 20 days. After the experiment, the mice were sacrificed under anesthesia and the aortas were obtained and frozen in liquid nitrogen for the preparation of frozen section slides and other experiments. The titer of AT1-EC2 was assayed by using ELISA. The level of NOX1 mRNA in the aorta was determined by using RT-PCR. The expression of NOX1 was detected by using Western blotting. Confocal scanning microscopy was used to assay the α-actin and NOX1 expression in the aortic tissue. The O(2)∸ production was detected in situ after DHE staining. The mice produced high level antibody against AT1-EC2 in AT1-EC2-immunized group and AT1-EC2-immunized and valsartan-treated group, and the level of NOX1 mRNA in the aortic tissues was 1.6±0.4 times higher and the NOX1 protein expression was higher in AT1-EC2-immunized group than in control group. There were no significant differences in the level of NOX1 mRNA and protein expression between control group and AT1-EC2-immunized and valsartan-treated group. The expression and co-localization of α-actin and NOX1 in AT1-EC2-immunized group increased significantly as compared with those in control group, and the O(2)∸ production increased about 2.7 times as compared with control group. There were no significant differences between control group and AT1-EC2-immunized and valsartan-treated group. It is concluded that active immunization with AT1-EC2 can activate NOX1-ROS, and increase vascular inflammation, which can be inhibited by AT1 receptor blocker valsartan. This may partially explain the mechanism of the pathogenesis of inflammatory vascular diseases related to antibody against AT1-EC2.
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The antibody against AT1-EC2 plays a role in some kinds of inflammatory vascular diseases including malignant hypertension, preeclampsia, and renal-allograft rejection, but the detailed mechanisms remain unclear. In order to investigate the changes of NADPH oxidase and reactive oxygen species in the aorta in a mouse model which can produce AT1-EC2 antibody by active immunization with AT1-EC2 peptide, 15 mice were divided into three groups: control group, AT1-EC2-immunized group, and AT1-EC2-immunized and valsartan-treated group. In AT1-EC2-immunized group and AT1-EC2-immunized and valsartan-treated group, the mice were immunized by 50 μg peptide subcutaneously at multiple points for 4 times: 0, 5, 10, and 15 days after the experiment. In AT1-EC2-immunized and valsartan-treated group, valsartan was given at a dose of 100 mg/kg every day for 20 days. After the experiment, the mice were sacrificed under anesthesia and the aortas were obtained and frozen in liquid nitrogen for the preparation of frozen section slides and other experiments. The titer of AT1-EC2 was assayed by using ELISA. The level of NOX1 mRNA in the aorta was determined by using RT-PCR. The expression of NOX1 was detected by using Western blotting. Confocal scanning microscopy was used to assay the α-actin and NOX1 expression in the aortic tissue. The O(2)∸ production was detected in situ after DHE staining. The mice produced high level antibody against AT1-EC2 in AT1-EC2-immunized group and AT1-EC2-immunized and valsartan-treated group, and the level of NOX1 mRNA in the aortic tissues was 1.6±0.4 times higher and the NOX1 protein expression was higher in AT1-EC2-immunized group than in control group. There were no significant differences in the level of NOX1 mRNA and protein expression between control group and AT1-EC2-immunized and valsartan-treated group. The expression and co-localization of α-actin and NOX1 in AT1-EC2-immunized group increased significantly as compared with those in control group, and the O(2)∸ production increased about 2.7 times as compared with control group. There were no significant differences between control group and AT1-EC2-immunized and valsartan-treated group. It is concluded that active immunization with AT1-EC2 can activate NOX1-ROS, and increase vascular inflammation, which can be inhibited by AT1 receptor blocker valsartan. This may partially explain the mechanism of the pathogenesis of inflammatory vascular diseases related to antibody against AT1-EC2.
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Animales , Ratones , Aorta , Metabolismo , Modelos Animales de Enfermedad , Ratones Endogámicos C57BL , NADPH Oxidasas , Genética , Especies Reactivas de Oxígeno , Metabolismo , Vacunación , MétodosRESUMEN
To observe the relationship between positive rate of β1-adrenergic and AT1 receptors autoantibodies with serum concentration of cystatin C in 371 patients with diabetic nephropathy patients,107 patients with type 2 diabetes,and 47 subjects as healthy control.In patients with diabetic nephropathy,the positive rates of the β1 and AT1 receptors autoantibodies were significantly higher than those in patients with type 2 diabetes and normal controls.The titers of β1 and AT1 receptors autoantibodies in diabetic nephropathy patients with abnormal cystatin C were significantly higher than those with normal cystatin C concentration.These findings suggested that β1 and AT1 receptors autoantibodie may play important roles in the pathogenesis of diabetic nephropathy.
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Autoimmune is involved in the pathogenesis of ventricular remodeling in acute myocardial infarction (AMI). In the present study, we investigated the effect of anti-cardiac myosin heavy chain antibodies (AMHCA) from patients with AMI on rat cardiomyocyte apoptosis. Cardiomyocyte apoptosis was observed and measured by DNA end labeling and Annexin-V/PI double-staining assay. The expression of apoptosis related p53 and Bcl-2 protein and the second messenger calcium were detected respectively by Western blotting, patch clamp and confocal calcium imaging. The results showed that AMHCA was able to induce cardiomyocyte apoptosis in a dose dependent manner. Apoptosis-accelerating nucleoprotein p53 was up-regulated, while apoptosis-inhibiting cytoplasmic protein Bcl-2 was down-regulated. In parallel, cytoplasmic calcium concentration was elevated. There was no effect on L-type calcium currents. It is concluded that AMHCA in patients with AMI as a novel triggering factor can induce cardiomyocyte apoptosis, which contributes to ventricular remodeling.
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Microthrombosis may be involved in the pathogenesis of cardiac microangiopathy due to diabetes. Recent studies have shown that fibrinogen-like protein 2 (fgl2) plays a pivotal role in microthrombosis in viral hepatitis, acute vascular xenograft rejection and cytokine-induced fetal loss syndrome. The current study was designed to examine the expression of fgl2 in microvascular endothelial cells and investigate the effects of microthrombi due to fgl2 on cardiac function and structure in rats with type 2 diabetes. Following induction of type 2 diabetes, 24 rats were observed dynamically. Fgl2 expression and related cardiac microthrombosis were examined. Local or circulating TNF-α was measured. Coronary flow (CF) per min was calculated as an index of cardiac microcirculation. Cardiac function and morphology were evaluated. It was found that Fgl2 was highly expressed in cardiac microvascular endothelial cells of rats with type 2 diabetes, which was promoted by local or circulating TNF-α. The Fgl2 expression was associated with cardiac hyaline microthrombosis. In parallel with the fgl2 expression, CF per min, cardiac diastolic or systolic function and cardiac morphology were aggravated to some extent. It was concluded that in rats with type 2 diabetes, microthrombosis due to fgl2 contributes to the impairment of cardiac diastolic or systolic function and morphological changes.
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Objective To explore the effects of tumor necrosis factor-α (TNF-α) on ventricular arrhythmias resulted from acute myocardial infarction (AMI) in rats. Method Two hundred and forty male Wistar rats were randomized (random number) into sham operation group, AMI group and recombinant human tumor necrosis factor receptor (rhTNFR) fusion protein (Fc) group. Acute anterior wall myocardial infarction was produced in rats of AMI group with ligating the left anterior descending coronary artery (LAD) , and the rats were just operated without ligation of LAD in sham group. The rats of Fc group were treated with rhTNFR-Fc (10 mg/kg), a TNF-α antagonist, 24 hours before LAD ligation. The original ECG was recorded 10 min before ligation and the ECGs of ventricular arrhythmias occurred spontaneously or induced by programmed electrical stimulation were recorded 10 min, 20 min, 30 min, 60 min, 3 h, 6 h and 12 hours after ligation. The protein levels and mRNA expressions of TNF-α in rats in different groups were detected with histochemistry and real-time fluorescent quantitative PCR. Results The expressions of TNF-α mRNA and levels of TNF-α protein markedly increased 10 min after infarction, reached the climax 20-30 min later, and then gradually returned to the original level in AMI group and Fc group. The time-windows of spontaneous and induced ventricular arrhythmias were consistent with the time-window of expressions of TNF-α mRNA and levels of TNF-α protein. Compared with AMI group, there were lower levels of TNF-α protein and lower incidence of ventricular arrhythmias in Fc group ( P < 0.05) , but there was no significant difference in TNF-α mRNA between two groups. There was no obvious change in TNF-α in rats of sham operation group. Conclusions The expressions of TNF-α mRNA and levels of TNF-α protein induced by AMI could contribute the initiation of ventricular arrhythmias.
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Objective To study the impact of depression disorder in patients after coronary stent implantation on incidence rate of in-stent restenosis (ISR) in the coronary heart disease( CHD ), and its possible pathophysiological mechanisms. Methods According to the Hamilton Depression Scale (HAMD-24) and Self-rating Depression Scale(SDS) score,95 patients with unstable angina received coronary drug-eluting stent implantation combined with depression disorder were serve as the study group; randomly selecte 246 cases without depression due to unstable angina pectoris after coronary stent implantation as the control group in the same period. The incidence rate of ISR in these two group were observed, and serum aldosterone ( ALD), high-sensitivity C-reactive protein (hs-CRP) ,Leptin levels in two groups were compared. Results The incidence rate of ISR in study group were significantly higher than that of the control group (28/95 vs 46/246, P＜0. 05). Following with the aggravation of depression disorder,the incidence rate of ISR were elevated( χ2 =8. 148, P=0.017). Serum ALD,hs-CRP and Leptin levels of study group were significantly higher than the control group 7 days later after drug-eluting stent implantation ( ALD:277.4 ± 35.9 vs 258.9 ± 60.9, t= 3. 459, P= 0. 001; hs-CRP: 12.03 ± 3.06 vs 11.10 ±2. 806, t = 2.573, P = 0.008; Leptin:5.27 t 1.07 vs 4.98 ± 0.99, t= 2.323, P= 0.021 ). Pearson correlation analysis showed that its HAMA-24 score was positively correlated with serum ALD ,hs-CRP and Leptin( r=0.291,P=0.026; r=0.350, P=0.014; r=0. 312, P=0.023) ,and SDS score was positively correlated with hs-CRP( r=0. 302, P= 0. 020). Conclusion Serum ALD, hs-CRP and Leptin levels are higher in patients after coronary stent implantation combined with depression in patients, and the incidence rate of ISR is also higher in these patients, and the rates are elevated according to the aggravation of depression disorder.
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Objective To investigate the association between albuminuria incidence and blood pressure (BP) level or body weight index (BMI) in patients with essential hypertension from five regions in China. Methods A total of 5021 non-diabetic patients with clearly diagnosed essential hypertension were enrolled in our study. The participants came from five cities in China.Urinary albumin/creatinine ratio was measured in these patients for two times. The associations of albuminuria with BP level and BMI were analyzed. Results (1)There was no significant difference of albuminuria incidence between ＜60-year-old and ≥60-year-old patients. The longer the hypertension exited, the higher the albuminuria incidence was. (2) The albuminuria incidence was associated with blood pressure level significantly. The urinary protein excretion increased with the level of blood pressure. The albuminuria incidences in patients with normal BP, upper range of normal BP, Ⅰ , Ⅱ or Ⅲ stage hypertension were 26.3%, 27.3%, 28.7%, 31.5% and 40.3% respectively. (3) The albuminuria incidence was significantly different in patients with uncontrolled BP (≥ 140/90 mm Hg) compared with those with well controlled BP (＜ 140/90 mm Hg) (27.1% vs 30.2%, P＜0.05 ). (4) The albuminuria incidence was higher in obese patients compared with those with normal BMI at same BP level, but the difference was not statistically significant. (5) Patients with albuminuria had more cardiocerebral or renal events as compared to those without proteinuria. Conclusions The albuminuria incidence of non-diabetic hypertensive patients from 5 cities in China is 28.8%, of which the microalbuminuria incidence is 18.6% and the clinical albuminuria incidence is 10.2%. Uncontrolled BP is an important risk factor of proteinuria.
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Aim To research the effect of diltiazem on cytokine expression and inflammatory cell activity in rat heart with ischemia/reperfusion.Methods The rats, underwent ischemia reperfusion, were divided into three groups:diltiazem group(D group),ischemia/reperfusion group (I/R group),and sham group (Sgroup).Echocardiogram was detected at 1,2,4 weeks after operation. RT-PCR was used to detect the inflammatory cytokines as IL-1β,TNF-α, IL-6 and anti-inflammatory cytokines as IL-10,TGF-β.Results Compared with I/R group,EF were increased and LVM, IL-β,TNF-α,IL-6 reduced significantly in D group.There was no significant/difference for IL-10 and TGF-β in three groups .Conclusion Diltiazem inhibits IL-1β,TNF-α, IL-6 expressions and inflammatory cell infiltration in rat heart with ischemia reperfusion.
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Aim To explore the cardiac cytokine expression in rat model of myocardial calcium overload, and the intervention from diltiazem.Methods The intracellular Ca~(2+) overload was induced by the isolated rat heart subjected to 5 min Ca~(2+) depletion and 30 min Ca~(2+) repletion (Ca~(2+) paradox) by the Langendorff technique.There were five groups in this study, including Ca~(2+) overload group, normal control group, Ca~(2+) depletion control group, Ca~(2+) overload-diltiazem group, and Ca~(2+) depletion-diltiazem group.The views of myocardial pathology and ultrastruction were observed by electron microscope and light microscope respectively. The cardiac intracellular [Ca~(2+)]_i was detected by atom spectrophotometer. The expression of TNF-α, IL-1β, L-6, TGF-β1, and IL-10 was detected by RT-PCR method.Results In Ca~(2+) overload group, few inflammatory cells were found in myocardium under the light microscope. And the views of electron microscope presented that cardiocyte membranes, nucleolus, and mitochondria were disorganized obviously.Compared with normal control group, the inflammatory cytokines as TNF-α, IL-1β, and IL-6 were increased significantly whereas there was nearly no difference of the expression of TGF-β1 and IL-10 in Ca~(2+) overload group.Ca~(2+) overload-diltiazem group showed that TNF-α, IL-1β, and IL-6 were decreased significantly. There were no statistical differences in the structure of myocardium, intracellular [Ca~(2+)]_i, and cardiac cytokines expressions in the three control groups, including normal control group, Ca~(2+) depletion control group and Ca~(2+) depletion-diltiazem group.Conclusions Instead of TGF-β1 and IL-10, the expression of TNF-α, IL-1β, and IL-6 is increased obviously in myocardium of calcium paradox model. Diltiazem can inhibit the cardiac expression of TNF-α, IL-1β, and IL-6 induced by myocardial calcium overload.
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Aim To research into the effect of diltiazem on cytokines expression in mononuclearcells induced by concanavalin A.Methods Ficoll density gradient centrifugation was used to separate the mononuclearcells from rat's spleen.There were 3 groups including control, Con A, diltiazem-Con A group in the study.The cytokines expressions in supernatant were detected by ELISA.Results Compared with control, IL-10, TNF-α, IL-6 were increased significantly in Con A group with low level IL-1β and non level TGF-β_1.But in diltiazem-Con A group, IL-10, TNF-α, IL-6 were decreased significantly compared with Con A group.Conclusion Diltiazem inhibits IL-10, TNF-α, IL-6 expressions in mononuclearcells induced by Con A.
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The cytokine repertoire of ADP/ATP carrier-specific humoral immune responses and the cytokine-dependent anti-ADP/ATP carrier antibody IgG subclasses were examined in a cohort of ADP/ATP carrier-immunized BALB/c mice treated with anti-CD4 monoclonal antibody. Eighteen male BALB/c mice (6-8 weeks old) were randomized into 3 groups: dilated cardiomyopathy (DCM) group, DCM-tolerance (Tol) group and control group. The mice in DCM group were immunized with the peptides derived from human ADP/ATP carrier protein for 6 months and mice in the control group were sham-immunized, while the mice in DCM-Tol group were immunized with ADP/ATP carrier protein and anti-CD4 McAb simultaneously. Serum autoantibody against ADP/ATP carrier and IgG subclasses were measured by ELISA, intracellular cytokines IFN-gamma and IL-4 of Th cells were monitored with flow cytometry, and splenic T cell cytokines IFN-gamma, IL-2, IL-4 and IL-6 were detected by using real-time fluorescent quantitative PCR. The results showed that the autoantibody against ADP/ATP carrier was found in all mice in DCM group, and the antibody level, serum IgG1 and IgG2a subclasses, cytokines in T cells and Th cells were all elevated in DCM group, as compared with those in control group (P<0.01). On the other hand, in DCM-Tol group, the autoantibody level and contents of all the cytokines were significantly different from those in DCM group (P<0.01), and were close to those in control group. And the levels of IgG1, IgG2a, IgG2b and IgG3 were influenced, to varying degrees, by anti-CD4 McAb as compared with those in DCM group. All these four types of IgG subclasses were substantially decreased in DCM-Tol group as compared with DCM group. It is concluded that the treatment with anti-CD4 McAb could prevent the activation of T cells, reverse the abnormal secretion of cytokines and the imbalance between Th1/Th2 cell subsets and abnormal production of autoantibody against ADP/ATP carrier, and eventually avoid myocardial injuries.
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In ischemic hypertrophic myocardium, contractile dysfunction can be attributed to the decreased calcium induced calcium release (CICR) in cytoplasm. This study aimed to investigate the electrophysiological properties and the expression of L calcium channel subunits in post-MI myocardium. The ischemic heart remodeling model was established in SD rats. The expressions of calcium channel subunits were determined by realtime RT-PCR. Whole cell patch clamp was used to record the electrophysiological properties of L calcium channel. The results showed that the L calcium channel agonist Bayk 8644 induced the significantly decreased CICR in the rat cardiomyocyte 6 weeks after myocardial infarction (MI). In the post-MI cardiomyocytes, the amplitude of I(CaL) decreased dramatically and the inactivation curve of the current shifted to more negative potential. At mRNA level, the expression of the calcium channel alpha1c, beta2c subunits decreased dramatically in the ventricle of post-MI rats. The expression of alpha2/delta subunit, however, remained constant. It is concluded that the abnormal expression of the L calcium channel subunits in post-MI cardiomyocytes contributes to the ICaL decrease at early stage of the ischemic remodeling in cardiomyocytes, which leads to the decreased CICR in the cell and contractile dysfunction of myocardium.
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The purpose of the study was to observe the effect of rapamycin (RAPA) on the differentiation and maturation of rat bone marrow-derived dendritic cells (BMDCs) in vitro. BMDCs from Wistar rats were cultured with granulocyte-macrophage colony-stimulating factor plus interleukin-4 in the presence or absence of RAPA (20 ng/mL), and stimulated with lipopolysaccharide (LPS) for 24 h before cells and supernatants were collected. Surface phenotype of BMDCs was flow-cytometrically detected to determine the expression of maturation markers, MHC class II and CD86. Supernatants were analyzed for the production of IL-12 and IFN-gamma cytokines by using ELISA. BMDCs were co-cultured with T cells from Lewis rats and mixed lymphocyte reaction was assessed by MTT method. The morphology of BMDCs stimulated with LPS remained immature after RAPA pretreatment. RAPA significantly decreased the CD86 expression, impaired the IL-12 and IFN-gamma production of BMDCs stimulated with LPS, and inhibited the proliferation of allogeneic T cells. In conclusion, RAPA can inhibit the maturation of BMDCs stimulated with LPS in terms of the morphology, surface phenotype, cytokine production, and ability of BMDCs to stimulate the proliferation of allogeneic T cells in vitro.
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Objective To investigate the relatonahip between TNF-α and ventricular arrhythmias after acute myocardial infarction(AMI)and its mechanism.Method Both the clinical and animal experiments were done.(1)Clinical experiment:Eighty patients with AMI were included in Union Hospital,Tongji Medical College,Huazhong University of Science and Techology,from May 2005 to November 2006 according to the WHO diagnostic criteria.Co-infection of diseases such as severe upper respiratory infection,lung infection,high fever,cancer,et al were excluded.The relationship between the levels of TNF-α and arrhythmias were observed at different times after AMI.A straight line correlation,analysis Was done.(2)Animal experiment:Different concentrations of TNF-αwere added to isohted rat hearts for observing the arrhythrnia effects.The effect of TNF-α on intracellular Ca2+ concentration was detected by laser confocal technique.All data were analyzed by SNK-q test using SPSS 13.0 sofeware prograrn.Results(1)The plasma levels of TNF-α were significantly associated with the Lown class of PVC after AMI and they were higher in AMI of anterior wall[(46.41±10.34)pg/ml]than other positions [(28.25±6.35)pg/ml,P<0.05].2)The frequency of ventricular arrhythmias was interrelated with the concentralions of TNF-α.Using etanercept beforehand,TNF-α induced a slight increase of intracellular Ca2+ intensity (P<0.05).Conclusions There was a relationship between TNF-αlevels and ventricular arrhythmisa in patients with AMI.Animal experiments confirmed the isolated heart perfusion with TNF-α induced ventricular arrhytrnias.Expression of TNF-α after AMI was related with the occurrence of ventricular arrhythrnias.The effect might be associated with the increased inuaeellular Ca2+ intensity caused by TNF-α.
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We have investigated the methods and mechanisms for analysis of the channel kinetics parameters of voltage-gated potassium channels, HERG (Human ether-à-go-go related gene) channels, in the process of electrophysiological recording. The current of HERG K+ channels expressed in Xenopus oocytes was studied using a two-electrode voltage clamp technique, and the channel kinetics parameters were analyzed through compiling different pulse protocol and recording the current. Results showed: (1) The HERG K+ channels, under conditions of being activated with depolarized pulse, expressed an inward-rectified property attributing to rapid inactivation. The activation curve could be obtained through fitting the depolarized potential and the following peak amplitude of tail current, while the parameters of time-dependent activation was obtained through fitting different depolarized duration and the corresponding peak amplitude of tail current. (2) The I-V relationship still exhibit marked inward rectification. Tail current decay traces were fitted with a bi-exponential function to determine the time constants of the fast and slow components of current decay. (3) The inactivation of HERG channels is voltage-dependent. The inactivation process was isolated with two different three-pulse protocols, with which the inactivation curve and nearly linear I-V relationship were obtained, respectively. Thus, altough the kinetics properties of HERG channels were complicated, the channels kinetics could be indirectly analyzed through differently designed pulse protocols, which provided the basis for investigation on Alanine-scanning mutagenesis and agent action.