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Objective To study the effect of cardiac contractility modulation (CCM) on TGFβ1/Smad/CTGF signaling pathway.Methods A rabbit heart failure (HF) model was established by ligating the ascending aortic root.Thirty rabbits were divided into sham operation group (n=10),HF group (n=10) and CCM group (n=10).Myocardial tissue collagen Ⅰ and collagen Ⅲ were analyzed with Sirius red staining,myocardial tissue hydroxyproline level was measured by chromometry,and expressions of TGFβ1,Smad3,Smad7,CTGF were detected by Western blot in 3 groups.Results Collagen Ⅰ,collagen Ⅲ and hydroxyproline content were highcr in HF group than in sham operation group,while collagen Ⅰ,collagen Ⅲ and hydroxyproline conten were lower in CCM group than in sham operation group (0.69±0.05 μg/mg vs 0.98±0.04 μg/mg,P＜0.05).The expression levels of TGFβ1,Smad3,CTGF were higher while those of Smad7 were lower in HF group than in sham operation group (P＜0.05).The expression levels of TGFβ1,Smad3,CTGF were lower while those of Smad7 were higher in CCM group than in HF group (0.49±0.03 vs 0.67±0.04,0.43±0.06 vs 0.59±0.06,0.45±0.08 vs 0.75±0.09,P＜0.05;0.43±0.08vs 0.26±0.04,P＜0.05).Conclusion CCM can improve the myocardial fibrosis in HF rabbits by downregulating the expression of TGFβ1,Smad3,CTGF and upregulating the expression of Smad7.
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Objective: To observe the impact of cardiac contractility modulation (CCM) on myocardial remodeling in rabbit model of chronic heart failure (CHF) with its possible mechanism. Methods: Rabbit HF model was established by ascending aortic root ligation; the animals were divided into 3 groups: Sham group, the animals received thoracotomy without aortic ligation, HF group and HF+CCM group, the HF animals received CCM treatment for 4 weeks. n=10 in each group. Cardiac function was measured by echocardiography at 12 and 16 weeks in each group respectively; myocardial tissue fibrosis and pathological changes were examined by Masson staining; plasma BNP level was assessed by ELISA; protein expressions of collagen I, collagen II, MMP2,MMP9, TIMP1 and galectin-3 in myocardial tissue were determined by Western blot analysis. Results: ① By echocardiography: with 12 weeks treatment, compared with Sham group, HF group and HF+CCM group had increased LVESD, LVEDD and decreased LVFS, LVEF, all P<0.05; with 16 weeks treatment, compared with HF group, HF+CCM group had improved LVESD, LVEDD, LVEF and LVFS, all P<0.05. ② Pathological changes:compared with Sham group, HF group showed increased collagen content in myocardial tissue, P<0.05; CCM treatment could partially decrease collagen accumulation, P<0.05. ③ After 12 weeks treatment, compared with Sham group, HF group and HF+CCM group presented elevated plasma BNP level, P<0.05; after 16 weeks treatment, compared with HF group, HF+CCM group presented reduced plasma BNP, while it was still higher than that in Sham group, P<0.05. ④ By Western blot analysis: compared with Sham group, HF group demonstrated increased protein expressions of collagen I, collagen II, MMP2, MMP9, TIMP1 and galectin-3 in myocardial tissue; the above indexes were much lower in HF+CCM group while still higher than those in Sham group, all P<0.05. Conclusion: CCM could improve myocardial remodeling in rabbit model of CHF which might be related to down-regulated protein expressions of collagen I, collagen III, MMP2, MMP9, TIMP1 and galectin3 in myocardial tissue.
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AAIM:To investigate the effect of atorvastatin ( ATO) on electrical remodeling, atrial ion channel protein expression and cardiac function in atrial tachypacing rabbits, and to explore the potential electrical mechanism of ATO in the prevention of atrial fibrillation.METHODS:The rabbits were subjected to atrial tachypacing at 600 min-1 in the absence or presence of treatment with atorvastatin (ATP and ATO groups) for 48 h, and the other 10 as sham group without pacing ( NP group) .The tachypacing model was performed by attaching pacing and testing electrodes to left atrial and connecting with custom animal cardiac pacemaker in the open-chest situation.The animals in ATO group were pretrea-ted with ATO for 7 d and continued during tachypacing.Serial atrial effective refractory period ( AERP) was measured in each rabbit at baseline, 8 h, 16 h, 24 h, 32 h, 40 h and 48 h with different cycle lengths.The changes of cardiac func-tions and cardiac structure were observed by cardiac ultrasonic cardiogram before and after atrial tachypacing.The expres-sion of atrial ion channel proteins CaLα1 and Kv4.3 was detected by Western blotting.RESULTS:Compared with NP group, AERP at cycle lengths of 150 and 200 ms, the adaption of AERP, and the levels of CaLα1 and Kv4.3 expression were all decreased in ATP and ATO group, especially in ATP group.Left atrial dimension ( LAD) was increased in pacing groups as compared with NP group (P<0.05) after pacing delivery for 48 h, while no difference between the formers was observed.No significant change of the left ventricular dimension ( LVD) and ejection fraction ( LVEF) among groups be-fore and after pacing was found.CONCLUSION:Atrial tachypacing significantly shorten AERP, resulting in poor adap-tion of AERP, while ATO pretreatment significantly attenuates the atrial electrical remodeling in rabbits, but had no effect on cardiac structure.ATO suppresses the down-regulation of atrial ion channel proteins CaLα1 and Kv4.3 expression after 48 h, which may be the potential ionic mechanism of atrial electrical remodeling for ATO.
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Objective To investigate the influence of Qiliqiangxin capsule on the exercise tolerance in patients with chronic heart failure. Methods 86 patients with chronic heart failure were selected and recruited into a control group and an observation group randomly. The patients in the control group were given angiotensin-converting enzyme inhibitor, diuretic,carvedilol or metoprolol and dixina. The patients in the observation group were given Qiliqiangxin capsule on the basis of the control group. The change of exercise tolerance and left ventricular ejection fraction in all patients were detected after 4 weeks.Results The distance of walking in 6 minutes increased for all patients after 4 weeks' treatment(P＜0.05), while the observation group increased more significantly than the control group(P＜0.05). The left ventricular ejection fraction increased for all patients after therapy 4 weeks (P＜0.05), while the observation group increased more obviously than the control group (P＜0.05). The total excellent rate and effective rate in the observation group were both higher than the control group (P＜0.05). Conclusion Qiliqiangxin capsule can increase the clinic curative effect by increasing the exercise tolerance and improving the heart function of patients with chronic heart failure.
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BACKGROUND: Bone marrow mesenchymal stem cells (BMSCs) can grow in host myocardium, differentiate under myocardial condition, improve cardiac function. However, biological characteristics of BMSC differentiation are still unclear presently.OBJECTIVE: To study the expression and electrophysiological characteristics of BMSC/n vitro connexin-43 following 5-azacitidine (5-aza) treatment.DESIGN, TIME AND SETTING: The cytological in vitro controlled study was perormed at the Heart Center, Hebei Provincial People's Hospital from July 2007 to February 2009.MATERIALS: A total of 24 male pigs aged 2 months were purchased from Exparimental Animal Center, Hebei Medical University.METHODS: Bilateral femoral bone marrow was obtained from pigs under sterile condition. BMSCs were harvested by Percoll density gradient in vitro. At passage 2, BMSCs were treated with 10 μmol/L 5-aza, and incubated in DMeM without inductor 24 hours later. Indices were measured I, 2, 3 weeks following induction. A control group was set up, which was not treated with 5-azacitidine. Following bone marrow extraction, experimental pigs were anesthetized to obtain ventricular muscle. Normal ventricular muscle cells were isolated and cultured by tissue block enzyme digestion method.MAIN OUTCOME MEASURES: Expression of connexin-43 was measured by immunohistochemical staining (ABC method). Ito current density and action potential were determined by patch clamp technique.RESULTS: At 1 and 2 weeks following 5-aza induction, some BMSCs were positive for connexin-43, with the presence of brown particles surrounding nuclei. At 3 weeks, positive rate of connexin-43 was 95%. The area with large cell density was presented with similar structure to normal myocardium. At +80 mV, compared with normal myocardial cells, Ito current density was significantly reduced in BMSCs following 1 and 2 weeks and in the control group (P < 0.05). Ito current density was significantly increased to a normal levels in BMSCs 3 weeks following induction (P > 0.05). No action potential was detected in BMSCs following 1 and 2 weeks of 5-aza, and action potential could be determined 3 weeks following induction, which was identical to normal myocardial cells.CONCLUSION: Through induced by 5-aza for three weeks, BMSCs have the similar expression of connexin-43 and electrophysiological characteristics as normal myocardium.
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BACKGROUND:Bone marrow stem cell transplantation can improve heart function and prevent ventricle remodeling.At present,the adult bone marrow stem cells used for transplantation primarily included bone marrow mononuclear cells (BM-MNCs) and mesenchymal stem cells (MSCs),and endothelial progenitor cells.The curative effects and precise mechanisms of transplantation of various bone marrow stem cells remain unknown.OBJECTIVE:To compare the effects of transplantation of autologous BM-MNCs and MSCs via the coronary artery on ventricle remodeling subsequent to acute myocardial infarction (AMI). DESIGN,TIME AND SETTING:Randomized controlled animal experiment performed at the Center for Clinical Research,Hebei Provincial People's Hospital,Electron Microscope Room,Hebei Medical University between March 2005 and December 2006.MATERIALS:Thirty-six male Jizhong pigs,were randomly divided into 4 groups:control group (n = 6),infarct model group (n = 10),BM-MNC group (n = 10),and MSC group (n = 10).METHODS:Porcine autologous BM-MNCs were isolated by gradient density centrifugation,and MSCs were obtained by adherence method.Prior to transplantation,both BM-MNCs and MSCs were colloidal gold labeled.Except the infract model group,pigs in the other 3 groups were developed into AMI models by oppressing the left anterior descending branch with balloon catheter.Ninety minutes after modeling,(6.0±1.3)×107 autologous BM-MNCs and (4.5±2.1)x 107 MSCs were respectively transplanted into pigs in the BM-MNC group and the MSC group via the coronary artery and cultured for 28 days.MAIN OUTCOME MEASURES:Observation of pathological changes of cardiac muscle tissue by light and electron microscope;Examination of cardiac function by ultrasonograph;Detection of the number of blood vessels and apoptotic myocardial cells,and expression of nuclear factor-κB (NF-κB) and troponin Ⅰ and its correlation to cardiac function by immunohistochemistry;Detection of mRNA expression of vascular endothelial growth factor (VEGF) and basic fibroblast growth factor (bFGF) in the cardiac tissue as well as its correlation to cardiac function by reverse transcription-polymerase chain reaction (RT-PCR).RESULTS:In the MSC group,there was proliferation of a great deal of blood vessels as well as growth of abnormal cell masses around the coronary vessels,while the BM-MNC group exhibited the "budding" of many capillary vessels.Prior to transplantation,cardiac function indices were basically similar among each group (F = 1.550,P＞0.05).Twenty-eight days after transplantation,left ventricular ejection fraction was significantly lower in the control,BM-MNC,and MSC groups than in the infarct model group (F = 5.30,P＜0.05),while endocardial fractional shortening was significantly higher (F = 10.67,P＜0.01).Compared with the infarct model group,the number of blood vessels in the infarct zone and infarct border zone was increased in the BM-MNC group (F=29.56-34.87,P＜0.01) and had no apparent change in the MSC group.In the BM-MNC and MSC groups,apoptotic myocardial cells in the infarct zone and infarct border zone were significantly reduced (F=14.31-35.34,P＜0.01 ) and troponin I expression rate was significantly increased (F=19.05,P＜0.01 ),as compared with the infarct model group.In addition,NF-κB positive rate in the infarct border zone was significantly lower in the BM-MNC and MSC groups than in the infarct model group (F=19.05,P＜0.01).VEGF gene expression level in the infarct border zone was significandy higher in the BM-MNC group than in the infarct model group and MSC group (F = 49.41,P＜0.01).bFGF gene expression level in the infarct border zone was significantly higher in the MSC group than in the infarct model and BM-MNC groups (F=4.71,P＜0.01).LVEF was negatively correlated to myocardial cell apoptosis rate and NF-κB level (r=-0.441 1,P＜0.05;r=-0.579 6,P＜0.01 ).LVEF was positively correlated to number of blood vessels,VEGF and bFGF expression (r=0.775,P＜0.01;r=0.565 1,P＜0.05;r=0.573 5,P＜0.05).CONCLUSION:Transplantation of both autologous BM-MNC and MSC via coronary artery can improve the condition of left ventricular remodeling subsequent to myocardial infarction.The improvement of cardiac functions is related to the increase of blood vessels,VEGF and bFGF expression,the decrease of myocardial cell apoptosis and NF-κ B level in cardiac muscle tissues after stem cell transplantation.BM-MNC transplantation better promotes blood vessel proliferation and VEGF expression in the cardiac tissue but produces worse effects on bFGF gene expression than MSC transplantation.
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Objective To find out the appropriate bedbound period after Coronary Arteriography (CAG) in order to reduce the complications and uncomfort caused by prolonged Bedbound period and affected limb immobilization.Methods 121 cases of CAG patients were randomly divided into the reduced period group (experiment group) and the conventional group (the control group),two ways of nursing and observation respectively.Result the rate of complication occurred in the experiment group much less than that of in the control group and the bedbound period were different as well.The above items showed statistics significance (P<0.005～0.05).Conclusion The reduced bedbound period decreases the suffering of CAG patients and provides the reliable clinical evidence for proper nursing approach in this field.