Cardioprotective effects of Guanxinshutong （GXST） against myocardial ischemia/ reperfusion injury in rats

Background The protective effects against reperfusion injury of cardioprotective drugs have recently been evaluated and found to be inadequate. Guanxinshutong （GXST）, a combination of the traditional herb and Mongolian medicine, is effective and safe in treating angina pectoris in clinical trials. We assess the cardioprotective effects of GXST against myocardial ischemia and reperfusion （MI/R） injury in rats and explore its possible mechanism. Methods Forty-five male Sprague Dawley rats were randomized into three groups： non-MlfR group （Sham, n = 15）, MUR group treated with vehicle （Control, n = 15） and MI/R group treated with GXST （Drug, n = 15）. MI/R was induced by ligation of the left anterior descending coronary artery （LAD） for 30 minutes, followed by 2/24 hour reperfusion in the Control and Drug groups. In the Sham group, the LAD was exposed without occlusion. GXST powder （in the Drug group） or saline （in the Control and Sham groups） were administered via direct gastric gavage from 7 day prior to surgery. Blood samples were collected from the carotid artery （10 rats each group） after 2 hours of reperfusion, to determine the levels of tumor necrosis factor-or （TNF-ct）, interleukin-1 ~ （IL-113）, interleukin-6 （IL-6） and intercellular adhesion molecule-1 （ICAM-1） using enzyme-linked immunosorbent assays. The animals were then sacrificed and the hearts were harvested for histopathology and western blot analysis. Infarct size was measured in the remaining five rats in each group after 24 hours reperfusion. Results GXST significantly decreased levels of TNF-ct, IL-1β, IL-6, ICAM-1, apoptosis index （AI） and infarct size. GXST also obviously inhibited nuclear factor kappa B （NF.r,B） activity when compared with the Control group （all P 〈 0.05）. Conclusions GXST is effective in protecting the myocardium against MI/R injury in rats. Its possible cardioprotective mechanism involves inhibition of the inflammatory response and apoptosis following MI/R injury.

Effects of static magnetic field on human umbilical vessel endothelial cell

Objective: To investigate the effects of static magnetic field(SMF) on the viability, adhesion molecule expression of human umbilical vessel endothelial cell. Methods: Magnetic flux intensity was 0. 1 mT, 1 mT, 10 mT. Cell viability and proliferation were measured with 3H-TdR and MTT methods; and apoptosis of human umbilical vein endothelial cell (HUVEC) was studied by flow cytometry and transmission electric microscopy. ELISA was used to measure the expression of ICAM-1 and VCAM-1 on endothelium. Results: 0. 1 mT SMF had no effects on the growth of HUVEC. however,SMF of 1 mT, 10 mT attenuated growth of HUVEC. 10 mT static magnetic field could induce apoptosis and necrosis of HUVEC. 10 mT SMF enhanced the expression of ICAM-1 and VCAM-1 on endothelium. Conclusion: The effect of SMF depends on the intensity of SMF. 10 mT SMF has adverse effects on human umbilical vessel endothelial cell.

Cardiomyocyte-like differentiation of human bone marrow mesenchymal stem cells after exposure to 5-azacytidine in vitro

Objective To investigate the potential of adult mesenchymal stem cells (MSCs) derived from human bone marrow to undergo cardiomyogenic differentiation after exposure to 5-azacytidine (5-aza) in vitro. Methods A small bone marrow aspirate was taken from the iliac crest of human volunteers, and hMSCs were isolated by 1.073g/mL Percoll and propagated in the right cell culturing medium as previously described. The phenotypes of hMSCs were characterized with the use of flow cytometry. The hMSCs were cultured in cell culture medium (as control) and medium mixed with 5-aza for cellular differentiation. We examined by immunohistochemistry at 21 days the inducement of desmin, cardiac-specific cardiac troponin I (cTnI), GATA 4 and connexin-43 respectively. Results The hMSCs are fibroblast-like morphology and express CD44+ CD29+ CD90+ / CD34- CD45- CD31- CD11a. After 5-aza treatment, 20-30% hMSCs connected with adjoining cells and coalesced into myotube structures after 14days. Twenty-one days after 5-aza treatment, immunofluorescence showed that some cells expressed desmin,GATA4, cTnI and connexin-43 in 5,10 μmol/L 5-aza groups, but no cardiac specific protein was found in neither 3μmol/L 5-aza group nor in the control group. The ratio of cTnI positively stained cells in 10 μmol/L group was higher than that in 5 μmol/L group (65.3 ± 4.7% vs 48.2 ± 5.4%, P ＜ 0.05). Electron microscopy revealed that myofilaments were formed. The induced cells expressed cardiac-myosin heavy chain (MyHC) gene by reverse transcription-polymerase chain reaction (RT-PCR). Conclusions Theses findings suggest that hMSCs from adult bone marrow can be differentiated into cardiac-like muscle cells with 5-aza inducement in vitro and the differentiation is in line with the 5-aza concentration. (J Geriatr Cardiol 2004;1(2) :101-107. )

Clinical significance of leukocyte chemiluminescence in patients with coronary heart diseases

In the present investigation,measurement of leukocyte chemiluminescence (CL) wasundertaken using micro-whole blood assay in 76 patients with coronary heart diseases (CHDs).The findings showed that there was a significant increase in leukocyte CL in patients with un-stable angina pectoris (UAP) and acute myocardial infarction (AM1) (P【0.01) and the in-crease was greater in AMI than that in UAP (P【0,01).It was found that leukocyte CL inAMI was correlated with the extent of the infarct and increased with the size of the infarct.Leukocyte CL in AMI patients who had received fibrinolytic treatment was markedly greaterthan that before treatment (P【0.05),suggesting that leukocytes may play an important rolein the pathogenesis of CHDs and may be involved in myocardial ischemia-reperfusion induced in-jury.The findings of the present study demonstrate that measurement of leukocyte CL may beof benefits for prognosis and treatment of CHDs.

In vivo bioluminescence imaging of hyperglycemia exacerbating stem cells on choroidal neovascularization in mice

AIM： To investigate the influence of hyperglycemia on the severity of choroidal neovascularization（CNV）,especially the involvement of bone marrow-derived cells（BMCs） and underlying mechanisms.·METHODS： BMCs from firefly luciferase（Fluc）/green fluorescent protein（GFP） double transgenic mice were transplanted into C57BL/6J wide-type mice. The recipient mice were injected intraperitoneally with streptozotocin（STZ） daily for 5 consecutive days to induce diabetes mellitus（DM）, followed by CNV laser photocoagulation.The BMCs recruitment in CNV exposed to hyperglycemia was firstly examined in Fluc/GFP chimeric mice by in vivo optical bioluminescence imaging（BLI） and in vitro Fluc assays. The CNV severity was evaluated by H＆E staining and choroidal flatmount. The expression of vascular endothelial growth factor（VEGF） and stromal cell derived factor-1（SDF-1） was detected by Western blot.·RESULTS： BLI showed that the BMCs exerted dynamic effects in CNV model in Fluc/GFP chimeric mice exposed to hyperglycemia. The signal intensity of transplanted Fluc＋GFP＋BMCs in the DM chimeric mice was significantly higher than that in the control chimeric mice with CNV induction at days 5, 7, 14 and 21（121861.67 ±9948.81 vs 144998.33 ±13787.13 photons/second/cm2/sr for control and DM mice, P5d〈0.05; 178791.67±30350.8 vs240166.67 ±22605.3, P7d〈0.05; 124176.67 ±16253.52 vs196376.67 ±18556.79, P14d〈0.05; 97951.60 ±10343.09 vs119510.00 ±14383.76, P21d〈0.05）, which was consistent with in vitro Fluc assay at day 7 [relative light units of Fluc（RLU1）], 215.00±52.05 vs 707.33±88.65, P 〈0.05; RLU1/relative light units of renilla luciferase（RLU2）, 0.90 ±0.17 vs 1.83 ±0.17, P 〈0.05]. The CNVs in the DM mice were wider than those in the control group at days 5, 7, 14 and21（147.83±17.36 vs 220.33±20.17 μm, P5d〈0.05; 212.17 ±24.63 vs 326.83 ±19.49, P7d〈0.05; 163.17 ±18.24 vs265.17 ±20.55, P14d〈0.05; 132.00 ±10.88 vs 205.33 ±12.98,P21d〈0.05）. The average area of CNV in the DM group was larger at 7d（20688.67±3644.96 vs 32218.00±4132.69 μm2,P 〈0.05）. The expression of VEGF and SDF-1 was enhanced in the DM mice.·CONCLUSION： Hyperglycemia promots the vasculo-genesis of CNV, especially the contribution of BMCs,which might be triggered by VEGF and SDF-1 production.

Expressions of matrix metalloproteinases and tissue inhibitor of metalloproteinases after bare and magnetic stent implantation in rabbits

Objective We aimed to investigate whether magnetic stent has preventive effect on in-stent restenosis by observing expressions of matrix metalloproteinase (MMP)2, MMP9, tissue inhibitor of matrix metalloproteinase (TIMP)1 and TIMP2 after balloon angioplasty, bare and magnetic stent implantation in rabbits. Methods Rabbits underwent balloon angioplasty, bare and magnetic stent implantation in the left iliac arteries. The changes of MMPs and TIMPs were examined at various time points in the injured arteries using the methods of zymography, Western blot analysis, reverse transcription-polymerase chain reaction (RT-PCR) and morphometric analysis. Results Balloon angioplasty group (BA) and magnetic stent group (MS) showed lower intrinsic gelatinolytic activity and higher expression of TIMPs with less intimae hyperplasia;Whereas bare stent (BS) group exhibited higher intrinsic gelatinolytic activity and lower expression of TIMPs with significant intimae hyperplasia. Conclusion Magnetic stent probably has preventive effect on in-stent restenosis by changing intrinsic matrix metalloproteinases activity and expression of TIMPs.

Natural anti-oxLDL IgM monoclonal antibody in the pathogenesis of atherosclerosis

Objective To explore the role and the possible molecular mechanisms of natural anti-oxLDL IgM monoclonal antibody played and involved in pathogenesis of atherosclerosis. Methods Natural anti-oxLDL IgM monoclonal antibody 3A6 was generated by using standard hybridoma production techniques. Influence of 3A6 on formation of foam cells was observed by Oil Red O staining and affinity of Na125I-conjugated oxLDL on the naive and LPS-activated macrophages. After LPS stimulation on macrophages, anti-TLR4 neutralizing mAb, p38MAPK specific inhibitor SB203580, NF-kB specific inhibitor PDTC or RNAi targeting Fcα/μ receptor (Fcamr) were applied, respectively. Results Natural anti-oxLDL IgM monoclonal antibody 3 A6 were found specifically inhibit the binding of CuoxLDL to naive macrophages but not the binding of CuoxLDL to LPS-activated macrophages. It also promoted the formation of CuoxLDL-mediated foam macrophages. 3A6 F(ab')2 or pre-incubation with un-related IgM inhibited the binding of 3A6/CuoxLDL complex to LPS-activated macrophages. LPS up-regulated the expression of Fcamr in macrophages in a dose- and time-dependent manner, which was attenuated by treatment with anti-TLR4. LPS induced the phosphorylation of p38MAPK and translocation of NF-kB p65, contributing to the up-regulated expression of Fcα/μ receptor in macrophages. Conclusions Natural anti-oxLDL IgM monoclonal antibody 3A6 specifically inhibited the binding of CuoxLDL to naive macrophages in vitro. However, LPS, through the Toll-like receptor (TLR)4 receptor, activated the p38MAPK and NF-kB pathways and up-regulated the expression of Fcα/μ receptor in macrophages, which promoted the binding of 3A6/CuoxLDL complex to macrophages through binding with Fc fragments and the formation of foam macrophages. Therefore, our findings provide a new explanation why bacterial infection deteriorates the pathogenesis of atherosclerosis.

Aggravation of Arrhythmia Induced by Antiarrhythmic Drugs during Electrophysiologic Testing

The purpose of our study is to evaluate aggravation of arrhythmia induced byantiarrhythmic drugs during electrophysiologic testing In 266 tests, patients with arrhythmia weretreated with quinidine, procainamide, mexiletine amicdarone, locainide pirmenol flacainide andnorpace and the results were analysed. Aggravation of arrhythmia induced by antiarrhythmic drugswas common, involving almost all antiarrhythmic drugs The incidence of aggravation was 21. 8%.There was no definite relationship between arrhythrnic aggravation and underlying heart diseases. Inno circumstances were blood levels in toxic range at the time of arrhythmic aggravation. Combinedwith antiarrhythmic drugs Ia+Ib (?) the incidence of aggravation of arrhythmia. Greatly wid-ened QRS might he a due to recognizing the danger of quinidine-induced arrhythmic aggravation.

Different suppressive effect of lidocaine on persistent Na^+ current and transient Na^+ current in dorsal root ganglion neurons

Objective ：To investigate the different suppressive effect of lidocaine on persistent Na^＋ current and transient Na^＋ current in injured or uninjured dorsal root ganglion neurons. Methods： Totally 23 SD rats were randomly divided into 2 groups： control group （n： 10） and chronically compressed DRG （dorsal root ganglion） group （CCD group, n= 13）. Rats were anesthetized and DRG was isolated. Single DRG neuron was isolated by enzymatic disassociation method. Persistent Na^＋ current （INap） and transient Na^＋ current （INaT） were elicited in voltage clamp mode. Results： The presence of INap was testified in most DRG neurons （38/46 neurons in CCD group and 31/39 neurons in control group, P〉0. 05）. However, the cur- rent density of INap in CCD group （4. 6±0. 6 pA/pF, n=38 neurons） was greater than that in control group （2.5±0.4 pA/pF, n=31 neurons） （P〈0. 05）. The characteristics of INap was observed and found that INap could he blocked by 0.2 μmol/L tetrodotoxin easily. Furthermore, the does-effect relationship of lidocaine on INaP and IN.T were also examined. INaP and IN.T were suppressed by different concentrations of li- docaine, the range for INap was 5-20 μmol/L and for INaT was 0. 05-2 mmol/L. Conclusion： INap and INaT were suppressed by different concentrations of lidocaine. INap was suppressed by very low concentration of lidocaine （5-20 μmol/L）. However, INaT could only be blocked by high concentration of lidocaine （0.05-2 mmol/L）.

Experimental study on gas production and solution composition during the interaction of femtosecond laser pulse and liquid

The process of ionizing normal saline induced by femtosecond laser is studied from the perspective of gas production rate and composition.When the repetition rate is less than 1000 Hz,each laser pulse independently generates ionization gas.At the same time,we discovered the inhibitory effect of meglumini diatrizoici on the ionization process and explained the reasons for this inhibition.Finally,the gas composition proved that the primary gas production mechanism of the femtosecond laser is the decomposition of water molecular,and the composition of the solution after the reaction proved the decomposition effect of the laser on meglumine.

Effects of the heparin-coated Wiktor-I stent on recovering the balance of ET-1 and CGRP after intracoronary stent implantation

Objective: To study the effects of heparin-coated stent (Wiktor-I) on recovering the balance between endothelin- 1(ET- 1) and calcitonin gene-related peptide (CGRP) both in the plasma of coronary sinus and peripheral vein after stent implantation. Methods: The patients with coronary artery disease (n=30) were divided into non-coated stent (NCS) group (n=16) and heparin-coated stent (HCS) group (n=14). Circulating ET-1 and CGRP levels were measured by radioimmunoassay (RIA) in the 2 groups at the paired sampling sites, namely the coronary sinus (Cs) and peripheral vein (Pv). The ratio of ET/CGRP was also calculated to reflect the balance of ET and CORP. Results: In NCS group plasma ET-1 concentrations exhibited 2 peaks at 0 mm and 12 h after stent implantation, CORP levels were highly consistent with that of ET-1, and the ratio of ET/CGRP increased markedly at post-PTCA 5 mm, persisting until post-stent 12 h. While in HCS group ET-1 levels and the ratio of ET/CGRP were decreased dramatically compared with that of NCS group at 5 min,10 mm and 12 h post-stent (P＜0.05, P＜0.01 and P＜0.05, respectively＝. There was no remarkable difference of CGRP levels between the 2 groups. Conclusions: Heparin-coated stent can decrease the post-stent circulating ET-1 levels and recover the balance between ET-1 and CGRP.

The Clinical and Angiograghic Outcome of 190 Cases after Stent Placement in Small Coronary Vessels

Objectives To invest the success procedure, immediate outcome after procedure, the rate of main adverse cardiac events after procedure and restenosis after stent placement in small coronary vessels. Methods 290 patients with selected or emergency stent implantation in small vessels from April, 1997 to March,2002. Total 299 vessels,304 lesions and 316 stents were statisted. The successs rate of procedure, immediate outcome after procedure, the rate of main adverse cardiac events after procedure and restenosis after stent placement in small coronary vessels were assessed. The patients were followed up 1 month to 4 years. Re-catheter angiography were done in 122/290 patients. Results The narrow rate of lesion dropped from 89% ± 12% before procedure to 5% ±5% after procedure (diameter). 202 patients were followed up 1 month (69.7%). 197/202 cases were survival. 5/202 cases died in 3hrs to 7days. 2/5 cases died of persistent hypotension after procedure. 1/5 case died of acute left heart failure. 2/5 cases died of sudden death. 180 cases were followed up 5 months to 4 years. The non-event survival (NES) rate was 73.3% (132/180). The re-angiography were done in 122 cases. Restenosis happened in 39 cases (30.3%). 37 patients repeated PCI. 2 patients went to CABG. 2 cases got angina recurrence and were proved second time restenosis by re-angiography. The third time PCI was done in 1 patient. The other patients went to CABG. 1 case died of chronic heart failure after 2 years, 1 case suffered acute myocardial infarction on artery stent implanted. Conclusions There are high success rate of procedure and perfect immediate outcome in stent placement in small vessels. Main adverse cardiac events did not increased. Non-event survial was satisfied in long term follow -up. Restenosis rate was showed slightly higher than the one of main vessels.

MicroRNA-15a/b are up-regulated in response to myocardial ischemia/reperfusion injury

Objective Several studies have indicated that miR-15a,miR-15b and miR-16 may be the important regulators of apoptosis.Since attenuate apoptosis could protect myocardium and reduce infarction size,the present study was aimed to find out whether these miRNAs participate in regulating myocardial ischemia reperfusion （I/R） injury.Methods Apoptosis in mice hearts subjected to I/R was detected by TUNEL assay in vivo,while flow cytometry analysis followed by Annexin V/PI double stain in vitro was used to detect apoptosis in cultured cardiomyocytes which were subjected to hypoxia/reoxygenation （H/R）.Taqman real-time quantitative PCR was used to confirm whether miR-15a/15b/16 were involved in the regulation of cardiac I/R and H/R.Results Compared to those of the controls,I/R or H/R induced apoptosis of cardiomyocytes was significantly iucreased both in vivo （24.4％ ± 9.4％ vs.2.2％ ± 1.9％,P ＜ 0.01,n =5） and in vitro （14.12％ ±0.92％ vs.2.22％ ± 0.08％）.The expression of miR-15a and miR-15b,but not miR-16,was increased in the mice I/R model,and the results were consistent in the H/R model.Conclusions Our data indicate miR-15 and miR-15b are up-regulated in response to cardiac I/R injury,therefore,down-regulation of miR- 15a/b may be a promising strategy to reduce myocardial apoptosis induced by cardiac I/R injury.

Cardiotrophin-1 promotes cardiomyocyte differentiation from mouse induced pluripotent stem cells via JAK2/STAT3/Pim-1 signaling pathway

Background The induced pluripotent stem cell （iPSC） has shown great potential in cellular therapy of myocardial infarction （MI）, while its application is hampered by the low efficiency of cardiomyocyte differentiation. The present study was designed to investigate the effects of cardiotrophin-1 （CT-1） on cardiomyocyte differentiation from mouse induced pluripotent stem cells （miPSCs） and the underlying mechanisms involved. Methods The optimal treatment condition for cardiomyocyte differentiation from miPSCs was established with ideal concentration （10 ng/mL） and duration （from day 3 to day 14） of CT-1 administration. Up-regulated expression of cardiac specific genes that accounted for embryonic cardiogenesis was observed by quantitative RT-PCR. Elevated amount of a-myosin heavy chain （ct-MHC） and cardiac troponin I （cTn I） positive cells were detected by immunofluorescence staining and flow cytometry analysis in CT- 1 group. Results Transmission electron microscopic analysis revealed that cells treated with CT- 1 showed better organized sacromeric structure and more mitochondria, which are morphological characteristic of matured cardiomyocytes. Western blot demonstrated that CT-1 promotes cardiomyocyte differentiation from miPSCs partly via JAK2/STAT3/Pim-1 pathway as compared with control group. Conclusions These findings suggested that CT-1 could enhance the cardiomyocyte differentiation as well as the maturation of mouse induced pluripotent stem cell derived cardiomyocytes by regulating JAK2/STAT3/Pim-1 signaling pathway.

Targeting PPARαin low ambient temperature exposure-induced cardiac dysfunction and remodeling

The present study demonstrates that the down-regulation of peroxisome proliferator-activated receptor-α(PPARα)results in chronic low ambient temperature(LT)exposure-induced cardiac dysfunction and remodeling,emphasizing the therapeutic potential of PPARαactivation strategies(e.g.,fenofibrate treatment)in LT-associated cardiac injury.

A novel biodegradable polymer-coated sirolimus-eluting stent:1-year results of the HELIOS registry

Background:The HELIOS stent is a sirolimus-eluting stent with a biodegradable polymer and titanium oxide film as the tie-layer.The study aimed to evaluate the safety and efficacy of HELIOS stent in a real-world setting.Methods:The HELIOS registry is a prospective,multicenter,cohort study conducted at 38 centers across China between November 2018 and December 2019.A total of 3060 consecutive patients were enrolled after application of minimal inclusion and exclusion criteria.The primary endpoint was target lesion failure(TLF),defined as a composite of cardiac death,non-fatal target vessel myocardial infarction(MI),and clinically indicated target lesion revascularization(TLR)at 1-year follow-up.Kaplan-Meier methods were used to estimate the cumulative incidence of clinical events and construct survival curves.Results:A total of 2998(98.0%)patients completed the 1-year follow-up.The 1-year incidence of TLF was 3.10%(94/2998,95%closed interval:2.54-3.78%).The rates of cardiac death,non-fatal target vessel MI and clinically indicated TLR were 2.33%(70/2998),0.20%(6/2998),and 0.70%(21/2998),respectively.The rate of stent thrombosis was 0.33%(10/2998).Age≥60 years,diabetes mellitus,family history of coronary artery disease,acute myocardial infarction at admission,and device success were independent predictors of TLF at 1 year.Conclusion:The 1-year incidence rates of TLF and stent thrombosis were 3.10%and 0.33%,respectively,in patients treated with HELIOS stents.Our results provide clinical evidence for interventional cardiologists and policymakers to evaluate HELIOS stent.Clinical trial registration:ClinicalTrials.gov,NCT03916432.

Active greeting technique: a mother-and-child catheter based technique to facilitate retrograde wire externalization in recanalization of coronary chronic total occlusion

Although retrograde approach has greatly improved the success rate of percutaneous coronary intervention(PCI) for coronary chronic total occlusion(CTO), retrograde wire externalization still remains challenging and time-consuming in some cases. Cases utilizing ‘‘Active Greeting Technique(AGT)", a mother-and-child catheter based technique to facilitate retrograde wire externalization, were extracted from Chronic Total Occlusion Club, China(CTOCC) database. AGT was performed by deep intubation a mother-and-child catheter(GuidezillaTMextension, 4 or 5 Fr inner catheter, and etc.) in combination with either reverse controlled antegrade or retrograde subintimal tracking(CART) technique or retrograde wire crossing technique. A total of 111 patients with 112 CTO lesions treated with this technique were retrospectively analyzed. Reverse CART technique and retrograde wire crossing technique were performed in 90.2% and 9.8% of all procedures. The utilization of GuidezillaTMextension, 4 Fr, and 5 Fr inner catheter accounted for 94.6%, 3.6%, and 1.8%, respectively. Externalization of retrograde wire was successful in all cases. No procedural complications were adjudicated to AGT. Complications independent of AGT included two target vessel perforations and two collateral perforations. No in-hospital major adverse cardiac events were found. AGT is a feasible and safe technique that facilitates retrograde wire externalization.

Electrophysiological characteristics of cardiomyocyte-like cells from rat bone marrow derived mesenchymal stem cells by four inductors

Background Bone marrow derived mesenchymal stem cel induced by different inductors individually or collectively. In s （BMdMSCs） can differentiate into cardiomyocyte-like cells this study, by inducing BMdMSCs with p53 inhibitor （p-fifty three inhibitor-alpha, PFT-a）, 5-azacytidine （5-AZA）, angiotensin-II （Ang-II） and bone morphogenic protein-2 （BMP-2） we compared the influences of four inductors on the differentiation of rat BMdMSCs into caridomyocyte like-cells. Methods BMdMSCs were collected from the bone marrow of Sprague Dawley rats and after the fourth generation, the purified cells were divided into five groups： 5-AZA （10 μmol/L）, Ang-II （0.1 μmol/L）, PFT-α （20 μmol/L）, BMP-2 （10μg/L） and control. The purity of the BMdMSCs and the cardiac differentiation rates were obtained by flow cytometry. The expressions of cTnT in the BMdMSCs after four weeks of induction were detected by immunofluorescence and the expressions of cTnl and Cx43 detected by Western blotting. The green fluorescent levels reflecting intracellular calcium transient function were determined by laser scanning confocal microscopy. The total potassium current levels of cells were measured on patch clamp. Results All inductors affected to a different degree the differentiation of BMdMSCs into cardiomyocyte-like cells and the expressions of cTnT, cTnl and Cx43 suggesting that the combination of inductors could be an improved method for cardiac regenerative medicine. In addition, the total potassium current level and calcium transient in PFT-a cardiomyocyte-like cells were higher than other groups. Conclusions The cardiac differentiation of BMdMSCs induced by PFT-α, 5-AZA, Ang-II and BMP-2 has been improved at different levels. PFT-a has an advantage of differentiation rate and electrophysiological function over other inductors.

Current state of myocardial tissue engineering

Ischemic heart disease and dilated cardiomyopathy followed by heart failure are a worldwide problem,which seriously challenge clinical outcomes and quality of life of patients. Heart failure is one of the major causes of morbility and mortality. The human heart cannot regenerate significantly because adult cardiomyocytes are terminally differentiated and cannot replicate after injury. The loss of cardiomyocytes accounts for a decrease in myocardial function, which leads to heart failure. Conservative treatment for cardiac conditions has focused on the reduction of workload, and protection from risk factors and has little therapeutic effect on patients in end-stage heart failure. Heart transplantation represents a life-saving and life-extending treatment modality for end-stage heart failure. In spite of advances in surgical techniques, the shortage of availability of donor organs has limited this treatment modality and has prompted researchers to develop alternative approaches. Cardiomyocyte regeneration is a prospective treatment modality, of which, in vitro engineering of myocardial tissue has had promising outcomes that should help cope with failing hearts in the future. Over the past years, much progress has been made to replace infarcted, non-functioning myocardium with newly formed tissue by means of cell-grafting techniques. Our country has made substantial progress in this field and promises a bright future for clinical management of heart failure.

Cardiac differentiation and electrophysiology characteristics of bone marrow mesenchymal stem cells

Objective To review the progress of cardiac differentiation and electrophysiological characteristics of bone marrow mesenchymal stem cells. Data sources The databases of PubMed, Springer Link, Science Direct and CNKI were retrieved for papers published from January 2000 to January 2012 with the key words of ＂bone marrow mesenchymal stem cells, cardiac or heart, electrophysiology or electrophysiological characteristics＂. Study selection The articles concerned cardiac differentiation and electrophysiological characteristics of bone marrow mesenchymal stem cells were collected. After excluding papers that study purposes are not coincident with this review or contents duplicated, 56 papers were internalized at last. Results For the treatment of myocardial infarction and myocardiac disease, the therapeutic effects of transplantation of bone marrow mesenchymal stem cells which have the ability to develop into functional myocardial cells by lots of methods have been proved by many researches. But the arrhythmogenic effect on ventricles after transplantation of bone marrow mesenchymal stem cells derived myocardial cells is still controversial in animal models. Certainly, the low differentiation efficiency and heterogeneous development of electricial function could be the most important risk for proarrhythmia. Conclusion Many studies of cardiac differentiation of bone marrow mesenchymal stem cells have paid attention to improve the cardiac differentiation rate, and the electrophysiology characteristics of the differentiated cells should be concerned for the risk for proarrhythmia as well.