Effect of transplantation of bone marrow stem cells on myocardial infarction size in a rabbit model

BACKGROUND:Intravenous transplantation has been regarded as a most safe method in stem cell therapies.There is evidence showing the homing of bone marrow stem cells(BMSCs) into the injured sites,and thus these cells can be used in the treatment of acute myocardial infarction(Ml).This study aimed to investigate the effect of intravenous and epicardial transplantion of BMSCs on myocardial infarction size in a rabbit model.METHODS:A total of 60 New Zealand rabbits were randomly divided into three groups:control group,epicardium group(group Ⅰ) and ear vein group(group Ⅱ).The BMSCs were collected from the tibial plateau in group Ⅰ and group Ⅱ,cultured and labeled.In the three groups,rabbits underwent thoracotomy and ligation of the middle left anterior descending artery.The elevation of ST segment>0.2 mV lasting for 30 minutes on the lead Ⅱ and Ⅲ of electrocardiogram suggested successful introduction of myocardial infarction.Two weeks after myocardial infarction,rabbits in group Ⅰ were treated with autogenous BMSCs at the infarct region and those in group Ⅱ received intravenous transplantation of BMSCs.In the control group,rabbits were treated with PBS following thoracotomy.Four weeks after myocardial infarction,the heart was collected from all rabbits and the infarct size was calculated.The heart was cut into sections followed by HE staining and calculation of infarct size with an image system.RESULTS:In groups Ⅰ and Ⅱ,the infarct size was significantly reduced after transplantation with BMSCs when compared with the control group(P<0.05).However,there was no significant difference in the infarct size between groups Ⅰ and Ⅱ(P>0.05).CONCLUSION:Transplantation of BMSCs has therapeutic effect on Ml.Moreover,epicardial and intravenous transplantation of BMSCs has comparable therapeutic efficacy on myocardial infarction.

Bone marrow mesenchymal stem cell transplantation combined with perindopril treatment attenuates infarction remodelling in a rat model of acute myocardial infarction

Objective: This study was performed to evaluate whether implantation of mesenchymal stem cell (MSC) would reduce left ventricular remodelling from the molecular mechanisms compared with angiotensin-converting enzyme inhibitors (ACEIs) perindopril into ischemic myocardium after acute myocardial infarction. Methods: Forty rats were divided into four groups: control, MSC, ACEI, MSC+ACEI groups. Bone marrow stem cell derived rat was injected immediately into a zone made ischemic by coronary artery ligation in MSC group and MSC+ACEI group. Phosphate-buffered saline (PBS) was injected into control group. Perindopril was administered p.o. to ACEI group and MSC+ACEI group. Six weeks after implantation, the rats were killed and heart sample was collected. Fibrillar collagen was observed by meliorative Masson’s trichome stain. Western Blotting was employed to evaluate the protein expression of matrix metalloproteinase (MMP)-2, matrix metalloproteinase (MMP)-9 in infarction zone. The transcriptional level of MMP2, MMP9 and tissue inhibitor of matrix metalloproteinase (TIMP)-1 in infarction area was detected by reverse transcriptase PCR (RT-PCR) analysis. Results: The fibrillar collagen area, the protein expression of MMP2, MMP9 and the transcriptional level of MMP2, MMP9 mRNA in infarction zone reduced in MSC group, ACEI group, and MSC+ACEI group. No significant difference was detected in the expression of TIMP1 mRNA among the 4 groups. Conclusion: Both MSC and ACEI could reduce infarction remodelling by altering collagen metabolism.

Experimental study of qishen yiqi drop pill combined with bone marrow mesenchymal stem cell transplantation on angiogenesis and cardiac function in mice with myocardial infarction

Objective:To investigate the effects ofQishengyiqi drop pill combined with bone marrow mesenchymal stem cell transplantation on angiogenesis and cardiac function in mice after myocardial infarction through in vitro cell molecular biology experiments.Methods:The animals used in this experiment were male mice with eGFP+/-.Sixty mice were randomly divided into three groups(n=20):myocardial infarction group(MI+PBS),myocardial infarction+mesenchyme plasma stem cell transplantation group(MI+MSCs)and myocardial infarction+Qishenyiqi drip pill combined with mesenchymal stem cell transplantation group(MI+MSCs+QSYQ).Qishenyiqi dripping pills were prepared into a medicinal solution with a concentration of 3.9 mg/mL with distilled water.The MI+MSCs+QSYQ group was orally administered with 0.1 mL/kg/day,and the other two groups were orally administered with an equal amount of normal saline.Mice in each group were adaptively fed continuously for 2 weeks,and the myocardial infarction model was established by ligation of the anterior descending coronary artery by thoracic ligation.Twenty-four hours after the model was established,bone marrow mesenchymal stem cells were isolated from the tibia of the mice and injected intracardiacly Bone marrow-derived mesenchymal stem cells were transplanted,and multiple injections were made around the myocardial infarction area of mice.The control group was injected with the same amount of PBS.0h,3 days,7 days,and 14 days after cell transplantation,observe the stem cell morphology under a microscope;on day 7 of cell transplantation,track the expression of eGFP-positive cells with a fluorescence microscope;before modeling,14 and 21 days after cell transplantation,use Cardiac function was measured by echocardiography.After 21 days of modeling,the mice were sacrificed,and heart samples were taken.The angiogenesis of the mice was observed by immunohistochemical staining and microvascular density determination.Results:The morphological growth of transplanted stem cells was proportional to the time of cell transplantation.Compared with MI+PBS group,CD90.2 and y6A were highly expressed on the surface of bone marrow mesenchymal stem cells in MI+MSCs group and MI+MSCs+QSYQ group,while CD31 and CD117 were almost not expressed.On the 21st day after stem cell transplantation,the values of LVDd and LVSD in MI+MSCs+QSYQ group were significantly lower than those in MI+PBS group and MI+MSCs group.At the same time,LVEF and LVFS increased significantly.The results of quantitative immunohistochemical analysis showed that the angiogenesis density in the MI+MSCs+QSYQ group increased significantly,and the difference between the groups was statistically significant(P<0.05).Conclusion:Qishen Yiqi dripping pills combined with bone marrow mesenchymal stem cell transplantation can not only promote angiogenesis in mice with myocardial infarction,but also play a positive role in improving cardiac function.

Optimal time for mesenchymal stem cell transplantation in rats with myocardial infarction

Background:Bone marrow mesenchymal stem cell (MSC) transplantation is a promising strategy in the treatment of myocardial infarction (MI). However, the time for transplanting cells remains controversial. The aim of this study was to find an optimal time point for cell transplantation. Methods: MSCs were isolated and cultured from Sprague-Dawley (SD) rats. MI model was set up in SD rats by permanent ligation of left anterior descending coronary artery. MSCs were directly injected into the infarct border zone at 1 h, 1 week and 2 weeks after MI, respectively. Sham-operated and MI control groups received equal volume of phosphate buffered saline (PBS). At 4 weeks after MI, cardiac function was assessed by echocardiography; vessel density was analyzed on hematoxylin-eosin stained slides by light microscopy; the apoptosis of cardiomyocytes was evaluated by terminal deoxynucleotidyl transferase-mediated dUTP nick end-labeling (TUNEL) assay; the expressions of proteins were analyzed by Western blot. Results: MSC transplantation improved cardiac function, reduced the apoptosis of cardiomyocytes and increased vessel density. These benefits were more obvious in 1-week group than in 1-h and 2-week groups. There are more obvious in-creases in the ratio of bcl-2/bax and the expression of vascular endothelial growth factor (VEGF) and more obvious decreases in the expression of cleaved-caspase-3 in 1-week group than those in other two groups. Conclusion: MSC transplantation was beneficial for the recovery of cardiac function. MSC transplantation at 1 week post-MI exerted the best effects on increases of cardiac function, anti-apoptosis and angiogenesis.

Transplantation of autologous bone marrow-derived mesenchymal stem cells for traumatic brain injury

Results from the present study demonstrated that transplantation of autologous bone marrow-derived mesenchymal stem cells into the lesion site in rat brain significantly ameliorated brain tissue pathological changes and brain edema, attenuated glial cell proliferation, and increased brain-derived neurotrophic factor expression. In addition, the number of cells double-labeled for 5-bromodeoxyuridine/glial fibrillary acidic protein and cells expressing nestin increased. Finally, blood vessels were newly generated, and the rats exhibited improved motor and cognitive functions. These results suggested that transplantation of autologous bone marrow-derived mesenchymal stem cells promoted brain remodeling and improved neurological functions following traumatic brain injury.

Magnetic resonance evaluation of transplanted mesenchymal stem cells after myocardial infarction in swine

Objectives To trace and evaluate intracoronary transplanted mesenchymal stem cells(MSCs) labeled with superparamagnetic iron oxide(SPIO) by using magnetic resonance imaging(MRI) in a swine model of myocardial infarction (MI).Methods MSCs were transfected with a lentiviral vector carrying the gene encoding green fluorescent protein (GFP) and labeled in vitro with SPIO.Two weeks after MI, swine were randomized to intracoronary transplantation of dual -labeled MSCs(n = 10),MSCs-GFP(n = 10) and saline(n = 5).MRI examination was performed with a 1.5T clinical scanner at 24 hours,3 weeks and 8 weeks after cells transplantation. Signal intensity(SI) changes,cardiac function and MI size were measured using MRI.Correlation between MR findings and histomorphologic findings was also investigated. Results The labeling efficiency at a combination of 25μg Fe/ml SPIO and 0.8 pi/ml Lipofectamine 2000 reached 100%.SPIO labeling did not affect GFP fluorescence and dual-labeling did not affect cell proliferation(P】0.05). Multipotentiality was not affected especially for cardiomyocyte-like cells differentiation.Cardiac cell marker of a-MHC and actinin were positively expressed by immunofluorescence staining after induction.SI on T2 * WI decreased substantial- ly in the interventricular septum 24 hours after injection of MSCs.The intensity of hypo-intense signals appeared to increase throughout the later time points.Changes in SI at 24 hours,3 weeks and 8 weeks were 52.98%±10.74%,21.53%±5.40%and 6.23%±2.01%,respectively(P【0.01).DE-MRI demonstrated both dual-labeled MSCSs and MSCs-GFP could dramatically reduce the size of MI and improve cardiac function. Histological data revealed that prussian blue stain-positive cells were found mainly in the border zone which also showed green fluorescence but negative for macrophage marker(CD68).Gross pathologic examination revealed that engrafted MSCs dramatically reduce the extent of necrotic myocardium and promote the regeneration of new,contractile myocardium along the subendocardial surface of the MI. Conclusions MSCs could be efficiently and safely labeled with SPIO and GFP,and could be detected reproducibly and noninvasively in vivo using cardiac MRI.Intracoronary transplantation of dual-labeled MSCs could increase cardiac function and reduce the size of MI.

Improvement of cardiac function after transplantation of autologous bone marrow mesenchymal stem cells in patients with acute myocardial infarction

Background The infarct size determines the long-term prognosis of patients with acute myocardial infarction (AMI). There is a growing interest in repairing scar area by transplanting bone marrow stem cells. However, effectiveness of intracoronary injection of bone marrow mesenchymal stem cells (BMSCs) in patients with AMI still remains unclear.Methods Sixty-nine patients with AMI after percutaneous coronary intervention (PCI) were randomly divided into intracoronary injection of BMSCs (n=34) and saline (control group, n=35) groups. Serial single positron emission computer tomography (SPECT), cardiac echo and cardiac electromechanical mapping were done at the designed time intervals until six months after transplantation of BMSCs or injection of saline. Results The proportion with functional defect decreased significantly in the BMSCs patients after three months [(13±5)%] compared with that pre-transplantation [(32±11)%] and the control group [(28±10)%] at three month follow-up (P<0.05, respectively). Wall movement velocity over the infracted region increased significantly in the BMSCs group [(4.2±2.5) cm/s vs (2.2±1.3) cm/s, P<0.05], but not in the control group [(2.2±1.5) cm/s vs (2.7±1.7) cm/s, P>0.05]. Left ventricular ejection fraction (LVEF) three months after transplantation in BMSCs group increased significantly compared with that pre-implantation and with that of the control group at three months post-injection [(67±11)% vs (49±9)% and (53±8)%, P<0.05 respectively]. SPECT scan results showed that perfusion defect was improved significantly in BMSCs group at three-month follow-up compared with that in the control group [(134±66)cm2 vs (185±87)cm2, P<0.01]. At the same time, left ventricular end-diastolic volume [(136±31) ml vs (162±27) ml, P<0.05] and end-systolic volume [(63±20) ml vs (88±19) ml, P<0.05] decreased synchronously. The ratio of end-systolic pressure to end-systolic volume [P_ syst/ESV, (2.84±1.30) mmHg/ml vs (1.72±1.23) mmHg/ml, P<0.05] increased significantly. Cardiac electromechnical mapping demonstrated significant improvement at three months after implantation of BMSCs compared with that pre-injection in both cardiac mechanical capability as left line local shorting [LLS, (11.29±1.64)% vs (7.32± 1.86)%, P<0.05] and electrical property as left ventricular endocardial unipolar voltage [UV, (10.38±1.12) mV vs (7.61±1.09) mV, P<0.01]; perfusion defect decreased from (36.2±6.2) % to (20.3±5.31)% (P<0.01). Twenty-four-hour electrocardiographic monitoring demonstrated no arrhythmias occurred at three-months follow-up.Conclusions The transplantation of BMSCs might improve the cardiac function and it is safe and feasible with no deaths or malignant arrhythmias.

Reconstruction of the adenosine system by bone marrow-derived mesenchymal stem cell transplantation

In the present study, we transplanted bone marrow-derived mesenchymal stem cells into the CA3 area of the hippocampus of chronic epilepsy rats kindled by lithium chloride-pilocarpine, Immunofluorescence and western blotting revealed an increase in adenosine A1 receptor expression and a decrease in adenosine A2a receptor expression in the brain tissues of epileptic rats 3 months after transplantation. Moreover, the imbalance in the A1 adenosine receptor/A2a adenosine receptor ratio was improved. Electroencephalograms showed that frequency and amplitude of spikes in the hippocampus and frontal lobe were reduced. These results suggested that mesenchymal stem cell transplantation can reconstruct the normal function of the adenosine system in the brain and greatly improve epileptiform discharges.

VEGF-expressing Bone Marrow Mesenchymal Stem Cells Transplantation Improved Heart Function of Myocardial Infarct Rabbits

Objectives To treat myocardial infarction with MSCs transplantation combined with VEGF gene therapy in rabbits and to study its mechanisms. Methods Forty-eight rabbits were randomly divided into MI group （n=12）, MSCs group （n=12）, VEGF group （n=12）, MSCs＋VEGF group （M＋V group, n=12）. Rabbit myocardial infarction models were founded by the ligation of left anterior descending artery. 107 MSCs were injected into the infarct-zone in four sites 2 weeks later in MSCs and M＋ V group, phVEGF gene were injected in infarct-zone in VEGF group and MSCs transfected with phVEGF gene were injected in M＋V group. Heart function including LVEDP, LVSP, LVDP, -dp/dtmax, ＋dp/dtmax, were measured in vivo. The hearts were harvested at 4 weeks after transplantation and sectioned for HE stain, immunohistochemical stain of BrdU and VIII factor antigen. Results The left ventricular hemodynamics parameters showed that heart function were improved more in M＋V group than MSCs group, MI group and VEGF group. The numbers of BrdU positive cells in M＋ V group（61±8）were more than in MSCs group （44±8, P 〈 0.01）. The numbers of vessels in infarcted zone were more in M＋V group （49±8） than in MSCs group （33±6, P 〈 0.01）,VEGF group（30±8, P 〈 0.01）and Mlgroup （18±4, P〈0.01）. Conclusions VEGF-expressing MSCs transplantation could improve heart function after myocardial infarction, and they were more effective than sole MSCs transplantation. Keeping more MSCs survival and ameliorating the blood supply of infarct-zone might be involved in the mechanisms.

Allograftic bone marrow-derived mesenchymal stem cells transplanted into heart infarcted model of rabbit to renovate infarcted heart

Objective: To investigate the directed transplantation of allograftic bone marrow-derived mesenchymal stem cells (MSCs) in myocardial infarcted (MI) model rabbits. Materials and Methods: Rabbits were divided into 3 groups, heart infarcted model with MSCs transplanted treatment (MSCs group, n=12), heart infarcted model with PBS injection (control group, n=20), sham operation with PBS injection (sham group, n=17). MSCs labelled by BrdUrd were injected into the MI area of the MSCs group. The same volume of PBS was injected into the MI area of the control group and sham group. The mortality, LVIDd, LVIDs and LVEF of the two groups were compared 4 weeks later. Tropomyosin inhibitory component (Tn Ⅰ) and BrdUrd immunohistochemistry identified the engrafted cells 4 weeks after transplantation. Result: The mortality of the MSCs group was 16.7% (2/12), and remarkably lower than the control group's mortality [35% (7/20) (P<0.05)]. Among the animals that survived for 4 weeks, the LVIDd and LVIDs of the MSCs group after operation were 1.17±0.21cm and 0.74±0.13cm, and remarkably lower than those of the model group, which were 1.64±0.14cm and 1.19±0.12cm (P<0.05); the LVEF of the MSCs group after operation was 63±6%, and remarkably higher than that of the model group, which was 53±6% (P<0.05). Among the 10 cases of animals that survived for 4 weeks in the MSCs group, in 8 cases (80%), the transplanted cells survived in the non MI, MI region and its periphery, and even farther away; part of them differentiated into cardiomyocytes; in 7 cases (70%), the transplanted cells participated in the formation of blood vessel tissue in the MI region. Conclusion: Transplanted allograftic MSCs can survive and differentiate into cardiomyocytes, form the blood vessels in the MI region. MSCs transplantation could improve the heart function after MI.

Human bone marrow-derived mesenchymal stem cells transplanted into damaged rabbit heart to improve heart function

Objective: The present study was designed to test whether transplantation of human bone marrow-derived mesen- chymal stem cells (hMSCs) in New Zealand rabbits with myocardial infarction can improve heart function; and whether engrafted donor cells can survive and transdifferentiated into cardiomyocytes. Methods: Twenty milliliters bone marrow was obtained from healthy men by bone biopsy. A gradient centrifugation method was used to separate bone marrow cells (BMCs) and red blood cells. BMCs were incubated for 48 h and then washed with phosphate-buffered saline (PBS). The culture medium was changed twice a week for 28 d. Finally, hematopoietic cells were washed away to leave only MSCs. Human MSCs (hMSCs) were premarked by BrdU 72 h before the transplantation. Thirty-four New Zealand rabbits were randomly divided into myocardial infarction (MI) control group and cell treated group, which received hMSCs (MI+MSCs) through intramyocardial injection, while the control group received the same volume of PBS. Myocardial infarction was induced by ligation of the left coronary artery. Cell treated rabbits were treated with 5×106 MSCs transplanted into the infarcted region after ligation of the coronary artery for 1 h, and the control group received the same volume of PBS. Cyclosporin A (oral solution; 10 mg/kg) was provided alone, 24 h before surgery and once a day after MI for 4 weeks. Echocardiography was measured in each group before the surgery and 4 weeks after the surgery to test heart function change. The hearts were harvested for HE staining and immunohistochemical studies after MI and cell transplantation for 4 weeks. Results: Our data showed that cardiac function was significantly improved by hMSC transplan- tation in rabbit infarcted hearts 4 weeks after MI (ejection fraction: 0.695±0.038 in the cell treated group (n=12) versus 0.554±0.065 in the control group (n=13) (P<0.05). Surviving hMSCs were identified by BrdU positive spots in infarcted region and transdifferentiated into cardiomyocytes characterized with a positive cardiac phenotype: troponin I. Conclusion: Transplan- tation of hMSCs could transdifferentiate into cardiomyocytes and regenerate vascular structures, contributing to functional im- provement.

Timing of transplantation of autologous bone marrow derived mesenchymal stem cells for treating myocardial infarction

It is still unclear whether the timing of intracoronary stem cell therapy affects the therapeutic response in patients with myocardial infarction.The natural course of healing the infarction and the presence of putative homing signals within the damaged myocardium appear to favor cell engraftment during the transendothelial passage in the early days after reperfusion.However,the adverse inflammatory environment,with its high oxidative stress,might be deleterious if cells are administered too early after reperfusion.Here we highlight several aspects of the timing of intracoronary stem cell therapy.Our results showed that transplantation of bone marrow mesenchymal stem cells at 2 4 weeks after myocardial infarction is more favorable for reduction of the scar area,inhibition of left ventricular remodeling,and recovery of heart function.Coronary injection of autologous bone marrow mesenchymal stem cells at 2 4 weeks after acute myocardial infarction is safe and does not increase the incidence of complications.

Effect of transplanted mesenchymal stem cells from rats of different ages on the improvement of heart function after acute myocardial infarction

Background Mesenchymal stem cells （MSCs） transplantation is of therapeutic potential after ischemic injury in both experimental and clinical studies. Clinically, elderly patients are more vulnerable to acute myocardial infarction （AMI）. But little is known about the characteristics of young donor-derived MSCs transplanted to old patients with AMI. The present study was designed to investigate the effect of transplanted MSCs from rats of different ages on the improvement of heart function after AMI. Methods MSCs from Sprague-Dawley （SD） rats were isolated and cultured in vitro. The apoptosis characteristics of MSCs were observed under conditions of ischemia and anoxia. SD rats underwent MI received intramyocardial injection of MSCs from young donor rats （n=-8）, old donor rats （n=-8）, respectively. AMI control group received equal volume physiological saline. Immunofluorescence was used to observe the differentiation of the grafted cells into cardiomyocytes Four weeks after cell transplantation, reverse transcriptase-polymerase chain reaction （RT-PCR） and immunohistochemistry for vascular endothelial growth factor （VEGF）, VIII-factor immunohistochemistry for vessel density, TUNEL, caspase-3 for cardiomyocyte apoptosis, echocardiography and hemodynamic detection for heart function were performed. Results The apoptosis rate of the old donor-derived MSCs group was significantly higher than that of the young donor-derived MSCs group under conditions of ischemia and anoxia （P 〈0.05）. Engrafted MSCs survived, proliferated and differentiated into myocardium-like cells. VEGF gene expression and capillary density in the old donor-derived group were lower than those in the young donor-derived group but higher than those in the control group （P 〈0.05）. The transplantation of old donor-derived MSCs attenuated apoptosis of cadiomyocytes in the peri-infract region compared with the control group and the effect was elevated in young donor-derived MSCs （P 〈0.05）. The heart functions （left ventricle ejection fraction （LVEF）, left ventricle fractional shortening （LVFS）） were improved more significantly in the old donor-derived MSCs group than in the control group and the heart function in the young donor-derived MSCs group further improved （P 〈0.05）. Conclusions Young donor-derived MSCs can improve heart function significantly through angiogenesis and decreasing cardiomyocyte apoptosis when transplanted to the infarcted area.

Therapeutic and regenerative potential of different sources of mesenchymal stem cells for cardiovascular diseases

Mesenchymalstemcells(MSCs)areidealcandidatesfortreatingmanycardiovasculardiseases.MSCscanmodify the internal cardiac microenvironment to facilitate their immunomodulatory and differentiation abilities,which are essential to restore heart function.MSCs can be easily isolated from different sources,including bone marrow,adipose tissues,umbilical cord,and dental pulp.MSCs from various sources differ in their regenerative and therapeutic abilities for cardiovascular disorders.In this review,we will summarize the therapeutic potential of each MSC source for heart diseases and highlight the possible molecular mechanisms of each source to restore cardiac function.

Vascular endothelial growth factor expressing mesen-chymal stem cells improves cardiac function in chronic myocardial infarction in pigs

Transplantation of mesenchymal stem cells （MSCs） for myocardial reconstruction has shown promise in both animal models and human phase 1 clinical studies. Vascular endothelial growth factor （VEGF） is a strong therapeutic agent for treating ischaemia by inducing angiogenesis. The feasibility of ex vivo MSCs mediated gene transfer is documented. Matsumoto and colleagues have recently reported genetically engineered MSCs carrying VEGF165 delivery for revascularization in a model of acute myocardial infarction （MI）. The promising data from our laboratory in both angiogenesis and MSCs transplantation in cunicular heart model of acute MI have prompted us to attempt the combined and simultaneous application of the two strategies.

Effects of Tongxinluo-facilitated cellular cardiomyoplasty with autologous bone marrow-mesenchymal stem cells on postinfarct swine hearts

Background Treatment of ischemic heart disease remains an important challenge, though there have been enormous progresses in cardiovascular therapeutics. This study was conducted to evaluate whether Tongxinluo （TXL） treatment around the transplantation of mesenchymal stem cells （MSCs） can improve survival and subsequent activities of implanted cells in swine hearts with acute myocardial infarction （AMI） and reperfusion. Methods Twenty-eight Chinese mini-pigs were divided into four groups including a control group （n=7）; group 2, administration of low-close TXL alone from the 3rd day prior to AMI to the 4th day post transplantation （n=-7）; group 3, MSCs alone （n=-7） and group 4, TXL ＋ MSCs （n=7）. AMI models were made by occlusion of the left anterior descending coronary artery for 90 minutes. Autologous bone marrow-MSCs （3×10^7 cells/animal） were then injected into the post-infarct myocardium immediately after AMI and reperfusion. The survival and differentiation of implanted cells in vivo were detected by immunofluorescent analysis. The data of cardiac function were obtained at baseline （1 week after transplantation） and endpoint （6 weeks after transplantation） by single photon emission computed tomography （SPECT） and magnetic resonance imaging （MRI）. Apoptosis was detected by TUNEL assay and the oxidative stress level was investigated in the post-infarct myocardium at endpoint. Results At endpoint, there was less fibrosis and inflammatory cell infiltration with more surviving myocardium in group 4 than in the control group. In group 4 the survival and differentiation of implanted MSCs were significantly improved more than that seen in group 3 alone （P〈0.0001）; the capillary density was also significantly greater than in the control group, group 2 or 3 both in the infarcted zone （P〈0.0001） and the peri-infarct zone （P〈0.0001）. MRI showed that parameters at baseline were not significantly different between the 4 groups. At endpoint, regional wall thickening and the left ventricular ejection fraction were increased while the left ventricular mass index, dyskinetic segments and infarcted size were decreased only in group 4 compared with control group （P〈0.0001）. SPECT showed that the area of perfusion defect was significantly decreased at endpoint only in group 4 compared with control group （P〈0.0001）. TUNEL assay indicated that TXL administration significantly decreased cell apoptosis in peri-infarct myocardium in groups 2 and 4. Furthermore, superoxide dismutase （SOD） significantly increased and malondialdehyde （MDA） decreased in groups 2 and 4 by the administration of TXL. Conclusions Our study demonstrates the following： （1） immediate intramyocardial injection of MSCs after AMI and reperfusion resulted in limited survival and differentiation potential of implanted cells in vivo, thus being incapable of beneficially affecting post-hearts; （2） TXL-facilitation resulted in a significant survival and differentiation potential of implanted cells in vivo via inhibition of apoptosis and oxidative stress, accompanied by significant benefits in cardiac function.

Mechanisms of improvement of left ventricle remodeling by transplanting two kinds of autologous bone marrow stem cells in pigs

Background The necrosis of a large number of myocardial cells after acute myocardial infarction （AMI） results in a decrease of cardiac function and ventricle remodeling. Stem cell transplantation could improve cardiac function after AMI, but the involving mechanisms have not been completely understood. The present study aimed to investigate the effects of transplantation of autologous bone marrow mononuclear cells （BM-MNC） and mesenchymal stem cells （MSCs） via the coronary artery on the ventricle remodeling after AMI as well as the mechanisms of the effects of transplantation of different stem cells on ventricle remodeling. Methods A total of 36 male pigs were enrolled in this study, which were divided into 4 groups： control group, simple infarct model group, BM-MNC transplantation group, and MSCs transplantation group. At 90 minutes when a miniature porcine model with AMI was established, transplantation of autologous BM-MNC （（4.7±1.7）×10^7） and MSCs （（6.2±1.6）×10^5） was performed in the coronary artery via a catheter. Ultrasound, electron microscope, immunohistochemical examination and real time reverse transcriptase-pelymerase chain reaction were used respectively to observe cardiac functions, counts of blood vessels of cardiac muscle, cardiac muscle nuclear factor （NF）-κB, myocardial cell apoptosis, and the expression of the mRNA of vascular endothelial growth factor （VEGF） and basic fibroblast growth factor （bFGF） in cardiac muscles. Multivariate Logistic regression was used to analyze the correlation factors of left ventricular end-diastolic diameter （EDD）. Results The number of blood vessels in the infarct zone and around its border in the BM-MNC transplantation group was more than those in the infarct model group and MSCs group （P=0.0001） and there was less myocardial cell apoptosis in the stem cell transplantation group than that in the infarct model group （all P 〈0.01）. The positive rate of NF-κB in the stem cell transplantation group was lower than that in the infarct model group （P=0.001）. The gene expression of VEGF in the infarct border zone of the BM-MNC group was higher than that in the MSCs group （P=0.0001）. The gene expression of bFGF in the infarct border zone in the MSCs transplantation group was higher than that in the infarct model group and the BM-MNC group （P=-0.0001）. Left ventricular ejection fraction was inversely proportional to the apoptotic rate of myocardial cells and cardiac muscle NF-κB but positively correlated with the number of blood vessels and the expression of VEGF and bFGF in the infarct zone and infarct border zone. The Multivariate Logistic regression analysis on the factors influencing the left ventricular end-diastolic diameter after stem cell transplantation showed that the expression of VEGF mRNA in the cardiac muscles in the infarct zone, the number of apoptotic myocardial cells and the expression of NF-κB in the infarct border zone were independent factors for predicting the inhibitory effect on the dilation of left ventricular EDD after stem cell transplantation. Conclusions Transplantation of autologous BM-MNC and MSCs in pigs can improve the condition of left ventricular remodeling and recover the cardiac functions after AMI. The improvement of cardiac functions is related to the increase of blood vessels, the increased expression of VEGF and bFGF, the reduction of myocardial cell apoptosis, and the decrease of NF-κB level in cardiac muscle tissues after stem cell transplantation.

有氧运动预适应改善骨髓间充质干细胞治疗急性心肌梗死的效果

背景:干细胞疗法是急性心肌梗死后恢复受损心肌组织的替代治疗策略,运动预适应可诱导机体产生内源性心脏保护效应,然而两者联合应用的疗效及机制尚不清楚。目的:探讨运动预适应联合骨髓间充质干细胞对急性心肌梗死大鼠治疗效果的影响及其可能机制。方法:70只雄性SD大鼠随机分为假手术组、模型组、干细胞治疗组、运动预适应组和联合干预组。运动预适应组和联合干预组于造模前进行8周跑台有氧运动,然后通过结扎冠状动脉前降支制作急性心肌梗死模型,干细胞治疗组和联合干预组于造模后隔天尾静脉注射骨髓间充质干细胞(1×10^(9)L^(-1),1 mL),治疗4周后,利用递增负荷跑台运动实验评估运动能力,超声心动图检测心脏结构与功能;分离左心室,2,3,5-氯化三苯基四氮唑染色评估心肌梗死面积,Masson染色检测胶原容积分数,CD31免疫组织化学染色检测心肌毛细血管密度,TUNEL染色检测心肌细胞凋亡情况,免疫印迹法检测基质细胞衍生因子1、CXC趋化因子受体蛋白4、肿瘤坏死因子α、白细胞介素10和血管内皮生长因子蛋白表达量。结果与结论:①干预疗效:与假手术组比较,模型组运动能力、左心室射血分数、左心室缩短分数、CD31阳性细胞率下降(P<0.05),心肌梗死面积、胶原容积分数和心肌细胞凋亡率增加(P<0.05)。与模型组比较,干细胞治疗组运动能力无显著差异(P>0.05),运动预适应组和联合干预组运动能力提高(P<0.05);干细胞治疗组、运动预适应组、联合干预组左心室射血分数、左心室缩短分数、CD31阳性细胞率升高(P<0.05),心肌梗死面积、胶原容积分数、心肌细胞凋亡率降低(P<0.05)。与干细胞治疗组比较,联合干预组运动能力、左心室射血分数、左心室缩短分数、CD31阳性细胞率增加(P<0.05),心肌梗死面积、胶原容积分数、心肌细胞凋亡率降低(P<0.05)。②蛋白表达:与假手术组比较,模型组肿瘤坏死因子α表达升高(P<0.05),白细胞介素10和血管内皮生长因子表达下降(P<0.05)。与模型组比较,干细胞治疗组和联合干预组CXC趋化因子受体蛋白4表达升高(P<0.05),干细胞治疗组、运动预适应组和联合干预组肿瘤坏死因子α表达下降(P<0.05),白细胞介素10和血管内皮生长因子表达增加(P<0.05)。与干细胞治疗组比较,联合干预组肿瘤坏死因子α表达降低(P<0.05),CXC趋化因子受体蛋白4、白细胞介素10和血管内皮生长因子表达升高(P<0.05)。结果表明:运动预适应可增强急性心肌梗死大鼠骨髓间充质干细胞治疗的效果(抑制心脏重塑、改善心功能、延缓心力衰竭进程),其机制与促进干细胞归巢、抑制炎症反应以及促进血管新生有关。

凋亡诱导因子基因敲减对骨髓间充质干细胞移植治疗心肌梗死的影响

背景:众多基础与临床试验证实:骨髓间充质干细胞移植后的低存活率严重制约着其发挥长期的治疗效果。课题组前期研究发现凋亡相关因子在骨髓间充质干细胞凋亡过程中发挥了重要作用,其中凋亡诱导因子(apoptosis-inducing factor,AIF)蛋白可能是其中一个关键因子。目的:将AIF敲减的骨髓间充质干细胞移植至小鼠梗死心肌中,验证低AIF表达骨髓间充质干细胞移植后的存活情况以及对进一步改善心功能的重要性。方法:首先,通过LV-AIF-shRNA慢病毒感染骨髓间充质干细胞下调AIF蛋白表达,应用流式细胞术及Western blot、RT-qPCR检测慢病毒的感染效率,CCK-8检测AIF敲减骨髓间充质干细胞在缺血缺氧条件下的细胞活力;然后,构建急性心肌梗死小鼠模型,分别将正常及AIF敲减的骨髓间充质干细胞移植至心肌梗死区域,免疫荧光检测AIF蛋白的表达,ELISA检测血清脑钠尿肽水平,心脏超声检测心功能,Masson染色观察心肌纤维化情况,RT-qPCR检测AIF敲减骨髓间充质干细胞移植后SRY基因表达反映细胞存活情况。结果与结论:①LV-AIF-shRNA慢病毒感染成功构建AIF基因敲减的骨髓间充质干细胞,感染效率为97.7%,且AIF表达有显著下降(P<0.001);②在缺血缺氧培养状态下,AIF基因敲减骨髓间充质干细胞较正常骨髓间充质干细胞的细胞活力显著增加;③与移植正常骨髓间充质干细胞相比,AIF基因敲减骨髓间充质干细胞移植后在梗死心肌中的存活数目显著升高至3.71倍(P<0.001),并且显著减少了梗死区域AIF蛋白表达、心肌纤维化程度;④与移植正常骨髓间充质干细胞相比,AIF基因敲减骨髓间充质干细胞移植后血清脑钠尿肽水平显著降低(P<0.05),左室射血分数、左室缩短分数均有显著改善(P<0.05);⑤结果表明:AIF基因敲减可通过增强骨髓间充质干细胞移植后的细胞活力、增加骨髓间充质干细胞在供体内的存活从而减少心肌纤维化,改善急性心肌梗死后心功能。