BACKGROUND: Experiments have confirmed that there are integrin receptors on bone marrow mesenchymal stem cells (BMSCs), but it is still uncertain whether angiogenin-1(Ang-1) can promote survival of BMSCs and protest against its apoptosis via integrins. OBJECTIVE: To investigate the effect of human recombinant angiopoietin-1 on adhesion, vigour, anti-apoptosis of rat BMSCs and its mechanism of signal transduction. DESIGN, TIME AND SETTING: The cytological in vitro controlled study was performed at the Opening Laboratory, Zhongshan Hospital Affiliated to Xiamen University from January to October 2008. MATERIALS: A total of 40 clean Sprague Dawley rats were supplied by Shanghai Experimental Animal Center, Chinese Academy of Sciences. Human Ang-1 (R&D) was used in this study. METHODS: Combining density gradient centrifugation and adherence separation was used to separate, cultivate and identify rat BMSCs. At the third to sixth passages, BMSCs were used for this study. Various matrix was used to coat 24-well culture plates for 1 hour. Following washing, monoplast suspension was added. Seven groups were set up. Group 1 served as control, BMSCs were coated with phosphate buffered saline containing 0.1% bovine serum albumin. BMSCs in the groups 2, 3 and 4 were incubated with vitronectin, fibronectin and Ang-1. BMSCs in the groups 5, 6 and 7 were firstly incubated in ethylenediaminetetraacetic acid, ?1 antibody and RGD antibody for 10 minutes, and then placed in a 24-well plate, and coated with Ang-1. MAIN OUTCOME MEASURES: Adhesion, trypan blue staining method, MTT test, Hoechst staining and Annexin V/PI were used to measure biological effects of Ang-1 on adherence, activity and anti-apoptosis of BMSCs. Combined with integrin antibody and signal transduction blocker, the expression of phosphoserine/threonine protein kinase B (pAkt), total Akt, Bcl-2 and ?-actin was examined by western blotting. RESULTS: Rat BMSCs were successfully isolated. The purity of BMSCs was 98.3% using flow cytometry. Cell adhesion assay shows Ang-1 promoted the adhesion of BMSCs at 1, 2 and 3 days compared with control group (P

Objective To investigate the influence of erythropoietin in the metabolism of extracellular matrix after myocardial ischemia-reperfusion injury.Methods The langendroff reperfusion system was applied to investigate the protective function of EPO in ischemia-reperfusion condition in rats.The effects of EPO on extracellular matrix were observed by Western blot and signal pathway blocker.The LVEDP and infarction area were observed at the same time.Results EPO significantly improved LVEDP [(19.8±0.2) mmHg vs (35.9±0.2) mmHg,IR group vs EPO +IR group,P＜0.05]and decreased infarction area (35.26%±7.13% vs 62.70%±7.23%,IR group vs EPO+IR group,P＜0.05).The expression of MMPs was significantly decreased and the expression of collagenase Ⅰ/Ⅲ was significantly enhanced by EPO (MMP2 53.2+2.6 vs 21.2+2.5;MMP9 57.6±3.1 vs 19.2±2.6;IR group vs IR+EPO group (P＜0.05);collagen Ⅰ 43.2±2.2 vs 11.4±2.3;collagen Ⅲ 55.3±3.2 vs 18.1 vs 2.3;IR+EPO group vs IR group (P＜0.05).This function can be inhibited by Mek-Erk inhibitor.Conclusion EPO plays a role in the metabolism of extracellular matrix by Mek-Erk signal pathway,which can protect the heart tissue from ischemia-reperfusion injury.

Objective To investigate the influence of Angiopoietin-1(Ang1)gene modified mesenchymal stem cells on the expression of adhension factors from endothelial cells,to clarify the feasibility of modulating inflammation reaction by gene modification after stem cells transplantation.Methods Genetic engineering rMSCs were constructed by lentivirally-tranduced Ang1 gene,the expressions of ICAM-1 and VCAM-1 at different time points after 20 ?g/L VEGF stimulating were investigated,the supernatants of gene modified rMSC were collected and then added into HUVEC culture with different concentrations of Ang1,the expressions of adhension factors after VEGF stimulated were observed at the same time.Results Genetic engineering rMSCs were successfully constructed,the expressions of ICAM-1 and VCAM-1 mRNA were significantly increased after VEGF stimulated,the maximal value was at 8 h,the ICAM-1 and VCAM-1 mRNA expressions were decreased after incubation with Ang1 at different concentrations,Ang1 suppressed the VEGF-stimulated protein levels of ICAM-1 and VCAM-1.Conclusion The supernatants of Ang1 gene modified stem cells can suppresse VEGF-stimulated inflammation reaction of HUVEC.

Objective To investigate the effects of bone marrow mesenchymal stem cells administration on VEGF,SDF-1 and TGF-?1 expressions and heart function in myocardial infarcts rats.Methods MSCs were harvested from SD rats,cultured and passaged in vitro,then the cells were purified by density gradient centrifugation and adhesive-screening method.Rats were randomly divided into 2 groups.In the control group(n=8) the animals were treated with saline of the same volume as placebo.Four weeks after the injection,the VEGF,SDF-1 and TGF-?1 expressions and heart function were examined.Results Four weeks after the transplantation,Immunohistochemistry showed expression of VEGF and SDF-1 increased markedly in experiment group,and expression of TGF-?1 decreased.Heart function was improved in the experiment group(P

Objective To investigate the efficacy and safety of catheter radiofrequency ablation of paroxysmal supraventricular tachycardia.Methods From Jul 2003 to Jan 2011,1106 cases with narrow QRS complex tachycardia who were treated by catheter radiofrequency ablation were recruited from our center and followed up for the rates of successful treatment,rcurrence and complications.Results There were in total 1106 patients (atrioventricular reentrant tachycardia:588 ; atrioventricular nodal reentrant tachycardia:477; atrial tachycardia:41 ),with a sex proportion of 1∶1.Successful ablation rate was 98.3 ％ (1087/1106).Of the 1087 successful ablation cases,43 (3.9％ )were warranted repeated ablation.The recurrent rates for trioventricular nodal reentrant tachycardia,atrioventricular reentrant tachycardia,left accessory pathway and right accessory pathway were 1.5％,5.6％,3.9％,and 9.1％ respectively.Complication rate was 1.5％.The major complications included pheumothorax ( 6 cases ),pulmonary embolism ( 1 case ),transient third-degree atrioventricular block ( 2 cases ),first-degree atrioventricular block ( 3 cases ),and persistent third-degree atrioventricular block(2 cases)with pacemaker implantation.There was one case of cardiogenic sudden death 5 days after the treatment procedure.The cause of his death was chronic stroke-related but not related to the operation procedure.Conclusion Catheter ablation has high efficacy and low complication rate in long-term follow-up,and is a promising treatment for paroxysmal supraventricular tachycardia.