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.

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.

Influence of Transplantation of Allogenic Bone Marrow Mononuclear Cells on the Left Ventricular Remodeling of Rat after Acute Myocardial Infarction

To probe into the influence of transplantation of allogenic bone marrow mononuclear cells （BM-MNCs） on the left ventricular remodeling of rat after acute myocardial infarction （AMI）, 60 male Wistar rats were evenly divided into three groups at random： control group 1, control group 2 and transplantation group. In control group 1, chest was opened without ligation of coronary artery; in control group 2 and transplantation group, the left anterior descending branch of coronary artery was ligated to establish AMI model. Prepared culture medium and allogenic BM-MNCs suspension were respectively implanted the surrounding area of infracted cardiac muscle via epicardium of control group 2 and transplantation group. Four weeks after the operation, the osteopontin gene （OPN mRNA, P〈0.01）, type Ⅰ collagen （P〈0.01） and angiotensin Ⅱ （AngⅡ, P〈0.01） content in the left ventricular non-infracted myocardium, and the Ang Ⅱ density in blood plasma （P〈0.05） of transplantation group and control group 2 were all significantly higher than that of control group Ⅰ. In the transplantation group, the myocardial OPN InRNA, type Ⅰ collagen and Ang Ⅱ content of non-infracted zone in left ventricle, and the Ang Ⅱ concentration in blood plasma were all significantly lower than those of control group 2 （P〈0.05 for all）. It is concluded that allogenic BM-MNCs transplantation may ease left ventricular remodeling after AMI by inhibiting the synthesis of type Ⅰ collagen in the cardiac muscle and down-regulating the expression of Ang Ⅱ and OPN gene.

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.

Short- and Long-term Therapeutic Efficacies of Intravenous Transplantation of Bone Marrow Stem Cells on Cardiac Function in Rats with Acute Myocardial Infarction:A Meta-analysis of Randomized Controlled Trials

Objective To investigate the short- and long-term therapeutic efficacies of intravenous transplantation of bone marrow stem cells(MSCs) in rats with experimental myocardial infarction by metaanalysis.Methods Randomized controlled trials were systematically searched from Pub Med,Science Citation Index(SCI),Chinese journal full-text database(CJFD) up to December 2014.While the experimental groups(MSCs groups) were injected MSCs intravenously,the control groups were injected Delubecco's minimum essential medium(DMEM) or phosphate buffered saline(PBS).Subgroup analysis for each outcome measure was performed for the observing time point after the transplantation of MSCs.Weighted mean differences(WMD) and 95% confidence intervals(CI) were calculated for outcome parameters including ejection fraction(EF) and fractional shortening(FS),which were measured by echocardiogram after intravenous injection and analyzed by Rev Man 5.2 and STATA 12.0.Results Data from 9 studies(190 rats) were included in the meta-analysis.As compared to the control groups,the cardiac function of the experimental groups were not improved at day 7(EF:WMD=0.08,95%CI-1.32 to 1.16,P>0.01; FS:WMD=-0.12,95%CI-0.90 to 0.65,P>0.01) until at day 14 after MSCs' transplantation(EF:WMD=10.79,95%CI 9.16 to 12.42,P<0.01; FS:WMD=11.34,95%CI 10.44 to 12.23,P<0.01),and it lasted 4 weeks or more after transplantation of MSCs(EF:WMD=13.94,95%CI 12.24 to 15.64,P<0.01; FS:WMD=9.64,95%CI 7.98 to 11.31,P<0.01).Conclusion The therapeutic efficacies of MSCs in rats with myocardid infarction become increasing apparent as time advances since 2 weeks after injection.

When is The Best Time of Stem Cell Transplantation for Treating Acute Myocardial Infarction──A Brief Meta-analysis of Current Clinic Trials

The best time of stem cells transplantation for treating acute myocardial infarction (AMI) is still to be followed with interest and a focus issue for clinical cardiologist. A brief meta-analysis of clinical trials about timing-window and therapeutic effects of stem cell transplantation for treating AMI will be made out in this article.

Peripheral blood stem cells transplantation in patients with heart failure after myocardial infarction:their efficiency and safety

Objective To compare the efficiency and safety of intracoronary transplantation of peripheral blood stem cells (PBSC) between elderly and younger patients with heart failure after myocardial infarction (MI). Methods Twenty-five patients with heart failure after MI were divided into aged group(≥60 years,n=13) and non-aged group(<60years,n=12)to receive intracoronary PBSC transplantation (PBSCT) following bone marrow cells mobilized by granulocyte colony-stimulating factor(G-CSF). Clinical data including coronary lesion characteristic, left ventricular shape,infarct region area and cardiac function, as well as adverse side effects between the two groups were compared. Left ventricular function was evaluated before and 6 months after the treatment by single photon emission computed tomography(SPECT). Results At 6 months, the left ventricular ejection fraction (LVEF) and 6 minute walk test (6MWT) distance increased, while the left ventricular diastolic diameter (LVDd) decreased significantly in both groups. There were no significant difference between the two groups in absolute change in the cardiac function parameters. Conclusions The present study demonstrated that autologous intracoronary PBSCT might be safe and feasible for both old and younger patients with heart failure after MI and left ventricular function is significantly improved.(J Geriatr Cardiol 2007;4:233-237.)

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.

The safety of autologous peripheral blood stem cell transplantation by intracoronory infusionin in patients with acute myocardial infarction

Objective Bone-marrow stem-cell transplantation has been shown to improve cardiac function in patients with AMI, but the safety of intracoronory infusion of autologous peripheral blood stem-cell(PBSCs) in patients with AMI is unknown. For this reason, we observe the feasibility and safety of PBSCs transplantation by intracoronory infusion in such patients.Method Fourty one patients with AMI were allocated to receive Granulocyte Colony-Stimulating Factor (G-CSF:Filgrastim,300 μg) with the dose of 300 μg-600 μg/day to mobilize the stem cell, and the duration of applying G-CSF was 5 days . On the sixth day, PBSCs were separated by Baxter CS 3000 blood cell separator into suspend liquid 57 ml. Then the suspend liquid was infused into the infarct related artery (IRA)by occluding the over the wire balloon and infusing artery through balloon center lumen. In the process of the intracoronary infusion of PBSCs, the complications should be observed, which were arrhythmias including of bradycardia, sinus arrest or atrial ventricular block, premature ventricular beats ,ventricular tachycardia, ventricular fibrillation; and hypotention, etc. Results There were total 10 cases with complications during the intracoronary infusion of PBSCs. The incidence of complications was 24.4%(10/41), including bradycardia is 2.4 %(1/41), sinus arrest or atrial ventricular block is 4.9%(2/41), ventricular fibrillation is 2.4 %( 1/41), hypotention is14.6 % (6 /41).Conclusions In patients with AMI, intracoronary infusion of PBSCs is feasible and safe.

The Safety of Autologous Peripheral Blood Stem Cell Transplantation by Intracoronory Infusion in Patients with Acute Myocardial Infarction

Objectives Bone-marrow stem-cell transplantation has been shown to improve cardiac function in patients with acute myocardial infarction (AMI) , but the safety of intracoronory infusion of autologous peripheral blood stem-cell (PBSCs) in patients with AMI is unknown. For this reason, we observe the feasibility and safety of PBSCs transplantation by intracoronory infusion in such patients. Methods 41 patients with AMI were allocated to receive granulocyte colony-stimulating factor (G- CSF: Filgrastim,300μg) with the dose of 300μg~ 600μg/day to mobilize the stem cell, and the duration of applying G-CSF was 5 days. On the sixth day, PBSCs were separated by Baxter CS 3000 blood cel 1 separator into suspend liquid 57 ml. Then the suspend liquid was infused into the infarct related artery (IRA) by occluding the over the wire balloon and infusing artery through balloon center lumen. In the process of the intracoronary infusion of PBSCs, the complications should be observed, which were arrhythmias including of bradycardia, sinus arrest or atrial ventricular block, premature ve. ntricular beats ,ven~icular tachycardia, ventricular fibrillation; and hypotention, etc. Results There were total 10 cases with complications during the intracoronary infusion of PBSCs. The incidence of complications was 24.4% (10/41), including bradyca- rdia was 2.4 % (1/41), sinus arrest or atrial ventri- cular block was 4.0% (2/41), ventricular fibrillation was 2.4 % (1/41), hypotention was 14.6 % (6/41). Conclusions In patients with AMI, intracoronary infusion of PBSCs is feasible and safe.

Progress in the treatment of myocardial infarction with stem cells transplantation

Embryonic stem cells and adult stem cells derives from bone marrow, muscule, liver, skin, nerve, adiposes and other tissues or organs are pluripotent. Embryonic stem cells in vitro can differentiate into derivatives of all three embryonic germ layers when transferred to an in vitro environment, and have the ability to form any fully differentiated cells of the body. A series of remarkable studies suggested that adult stem cells undergo novel patterns of development named as transdifferentiation. All of them can be induced into cardiomyocytes in a certain condition and used to treat myocardial infarction. In this review, progress in the treatment of myocardial infarction with stem cells transplantation is summarized.

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.

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.

TCMATHF:a bioinformatics platform to predict pharmacological action of drug and dynamic molecular changes against from myocardial infarction to heart failure

OBJECTIVE To investigate the characteristics and regulations of medication in different stages of disease by constructing a dynamic disease network and a cellular feature network spanning from myocardial infarction to heart failure.METHODS Based on transcrip⁃tome and single-cell sequencing data from a mouse model of left anterior descending coro⁃nary artery ligation,a dynamic early-middle-late network and cellular feature network were con⁃structed by integrating differential gene expres⁃sion trends and biological functions.The robust⁃ness of the perturbation effect of traditional Chi⁃nese medicine(TCM)on the disease network was calculated based on multi-target TCM,and we acquired the foundational data by analyzing the results of effectiveness.The predictive plat⁃form was scrutinized and assessed with regards to the functional attributes of FDA approveddrugs and compound prescriptions,in order to determine the primary stages of intervention and the drug patterns actions in the progression of heart failure.RESULTS In this study,we devel⁃oped a prediction and analysis platform for assessing the efficacy of drugs using a networkbased approach.The accuracy of the system was validated by FDA approved-drugs.It was found that blood-activating drugs,heat-clearing drugs,and phlegm-expelling drugs exhibited favorable intervention effects during the early to middle stages of the disease by investigating the effects of single herbs and TCM prescriptions on disease progression.Similarly,phlegm-expelling drugs,spirit-nourishing drugs,and diuretic showed better intervention effects during the mid⁃dle to late stages.These findings were consis⁃tent with the clinical use of drugs.Analysis of the clustering heatmap results of TCM prescriptions revealed that the formulas aimed at qi stagnation and blood stasis had a strong effect in early stage,while the formulas for qi and yin deficiency and cardiorenal yang deficiency had a strong effect in the middle to late stages.Furthermore,analysis of the single-cell feature network demon⁃strated that TCM had advantages in modulating the changes in fibroblasts,myofibroblasts,endo⁃thelial cells,and granulocytes during the patho⁃logical process.Additionally,most prescriptions exhibited strong perturbation effects on the fea⁃ture network of NK-T cells,granulocytes,macro⁃phages,and myofibroblasts.CONCLUSION This platform quantitatively evaluates the primary action stages and characteristics of TCM and for⁃mulas involved in the dynamic process of myo⁃cardial infarction to heart failure based on the effective prediction of the efficacy of TCM and FDA approved-drugs.It provides reference for the precise clinical application of TCM and formu⁃las with multiple targets and multiple pathways.

Stem cell mechanisms during left ventricular remodeling post-myocardial infarction:Repair and regeneration

Post-myocardial infarction(MI),the left ventricle(LV)undergoes a series of events collectively referred to as remodeling.As a result,damaged myocardium is replaced with fibrotic tissue consequently leading to contractile dysfunction and ultimately heart failure.LV remodeling post-MI includes inflammatory,fibrotic,and neovascularization responses that involve regulated cell recruitment and function.Stem cells(SCs)have been transplanted post-MI for treatment of LV remodeling and shown to improve LV function by reduction in scar tissue formation in humans and animal models of MI.The promising results obtained from the application of SCs post-MI have sparked a massive effort to identify the optimal SC for regeneration of cardiomyocytes and the paradigm for clinical applications.Although SC transplantations are generally associated with new tissue formation,SCs also secrete cytokines,chemokines and growth factors that robustly regulate cell behavior in a paracrine fashion during the remodeling process.In this review,the different types of SCs used for cardiomyogenesis,markers of differentiation,paracrine factor secretion,and strategies for cell recruitment and delivery are addressed.

Fifteen years of bone marrow mononuclear cell therapy in acute myocardial infarction

In spite of modern treatment, acute myocardial infarction(AMI) still carries significant morbidity and mortality worldwide. Even though standard of care therapy improves symptoms and also long-term prognosis of patients with AMI, it does not solve the critical issue, specifically the permanent damage of cardiomyocytes. As a result, a complex process occurs, namely cardiac remodeling, which leads to alterations in cardiac size, shape and function. This is what has driven the quest for unconventional therapeutic strategies aiming to regenerate the injured cardiac and vascular tissue. One of the latest breakthroughs in this regard is stem cell(SC) therapy. Based on favorable data obtained in experimental studies, therapeutic effectiveness of this innovative therapy has been investigated in clinical settings. Of various cell types used in the clinic, autologous bone marrow derived SCs were the first used to treat an AMI patient, 15 years ago. Since then, we have witnessed an increasing body of data as regards this cutting-edge therapy. Although feasibility and safety of SC transplant have been clearly proved, it's efficacy is still under dispute. Conducted studies and meta-analysis reported conflicting results, but there is hope for conclusive answer to be provided by the largest ongoing trial designed to demonstrate whether this treatment saves lives. In the meantime, strategies to enhance the SCs regenerative potential have been applied and/or suggested, position papers and recommendations have been published. But what have we learned so far and how can we properly use the knowledge gained? This review will analytically discuss each of the above topics, summarizing the current state of knowledge in the field.

Bilateral olfactory ensheathing cell transplantation promotes neurological function in a rat model of cerebral infarction

In the present study, olfactory ensheathing cells were transplanted into the cortices of infarcted （infarct transplantation group）, normal （normal transplantation group）, and bilateral hemispheres （bilateral transplantation group）. Olfactory ensheathing cells migrated to the infarct focus. The number of growth associated protein 43-positive cells and nerve fibers was slightly increased in the infarct area. These changes were more evident in the bilateral cortical transplantation group. Results demonstrated that transplanted olfactory ensheathing cells can migrate in rats with cerebra infarction. The olfactory ensheathing cells on the normal side can also promote neurological function. Bilateral cortical transplantation exhibited superior effects over unilateral transplantation.

Combination of mesenchymal stem cells and three-dimensional collagen scaffold preserves ventricular remodeling in rat myocardial infarction model

BACKGROUND Cardiovascular diseases are the major cause of mortality worldwide.Regeneration of the damaged myocardium remains a challenge due to mechanical constraints and limited healing ability of the adult heart tissue.Cardiac tissue engineering using biomaterial scaffolds combined with stem cells and bioactive molecules could be a highly promising approach for cardiac repair.Use of biomaterials can provide suitable microenvironment to the cells and can solve cell engraftment problems associated with cell transplantation alone.Mesenchymal stem cells(MSCs)are potential candidates in cardiac tissue engineering because of their multilineage differentiation potential and ease of isolation.Use of DNA methyl transferase inhibitor,such as zebularine,in combination with three-dimensional(3D)scaffold can promote efficient MSC differentiation into cardiac lineage,as epigenetic modifications play a fundamental role in determining cell fate and lineage specific gene expression.AIM To investigate the role of collagen scaffold and zebularine in the differentiation of rat bone marrow(BM)-MSCs and their subsequent in vivo effects.METHODS MSCs were isolated from rat BM and characterized morphologically,immunophenotypically and by multilineage differentiation potential.MSCs were seeded in collagen scaffold and treated with 3μmol/L zebularine in three different ways.Cytotoxicity analysis was done and cardiac differentiation was analyzed at the gene and protein levels.Treated and untreated MSC-seeded scaffolds were transplanted in the rat myocardial infarction(MI)model and cardiac function was assessed by echocardiography.Cell tracking was performed by DiI dye labeling,while regeneration and neovascularization were evaluated by histological and immunohistochemical analysis,respectively.RESULTS MSCs were successfully isolated and seeded in collagen scaffold.Cytotoxicity analysis revealed that zebularine was not cytotoxic in any of the treatment groups.Cardiac differentiation analysis showed more pronounced results in the type 3 treatment group which was subsequently chosen for the transplantation in the in vivo MI model.Significant improvement in cardiac function was observed in the zebularine treated MSC-seeded scaffold group as compared to the MI control.Histological analysis also showed reduction in fibrotic scar,improvement in left ventricular wall thickness and preservation of ventricular remodeling in the zebularine treated MSC-seeded scaffold group.Immunohistochemical analysis revealed significant expression of cardiac proteins in DiI labeled transplanted cells and a significant increase in the number of blood vessels in the zebularine treated MSC-seeded collagen scaffold transplanted group.CONCLUSION Combination of 3D collagen scaffold and zebularine treatment enhances cardiac differentiation potential of MSCs,improves cell engraftment at the infarcted region,reduces infarct size and improves cardiac function.

Improvement of learning and memory abilities and motor function in rats with cerebral infarction by intracerebral transplantation of neuron-like cells derived from bone marrow stromal cells

BACKGROUND： Transplantation of fetal cell suspension or blocks of fetal tissue can ameliorate the nerve function after the injury or disease in the central nervous system, and it has been used to treat neurodegenerative disorders induced by Parkinson disease. OBJECTIVE： To observe the effects of the transplantation of neuron-like cells derived from bone marrow stromal cells （rMSCs） into the brain in restoring the dysfunctions of muscle strength and balance as well as learning and memory in rat models of cerebral infarction. DESIGN ： A randomized controlled experiment.SETTING ： Department of Pathophysiology, Zhongshan Medical College of Sun Yat-sen University.MATERIALS ： Twenty-four male SD rats （3-4 weeks of age, weighing 200-220 g） were used in this study （Certification number：2001A027）. METHODS： The experiments were carried out in Zhongshan Medical College of Sun Yat-sen University between December 2003 and December 2004. ① Twenty-four male SD rats randomized into three groups with 8 rats in each： experimental group, control group and sham-operated group. Rats in the experiment al group and control group were induced into models of middle cerebral artery occlusion （MCAO）. After in vitro cultured, purified and identified with digestion, the Fischer344 rMSCs were induced to differentiate by tanshinone IIA, which was locally injected into the striate cortex （18 area） of rats in the experimental group, and the rats in the control group were injected by L-DMEM basic culture media （without serum） of the same volume to the corresponding brain area. In the sham-operated group, only muscle and vessel of neck were separated. ② At 2 and 8 weeks after the transplantation, the rats were given the screen test, prehensile-traction test, balance beam test and Morris water-maze test. ③ The survival and distribution of the induced cells in corresponding brain area were observed with Nissl stained with toluidine blue and hematoxylin and eosin （HE） staining in the groups.MAIN OUTCOME MEASURES ： ① Results of the behavioral tests （time of the Morris water-maze test screen test, prehensile-traction test, balance beam test）; ② Survival and distribution of the induced cells.RESULTS： All the 24 rats were involved in the analysis of results. ① Two weeks after transplantation, rats with neuron-like cells grafts in the experimental group had significant improvement on their general muscle strength than those in the control group [screen test： （9.4±1.7）, （4.7±1.0） s, P 〈 0.01]; forelimb muscle strength [prehensile-traction test： （7.6±1.4）, （5.2±1.2） s, P 〈 0.01], ability to keep balance [balance beam test： （7.9±0.74）, （6.1±0.91） s, P 〈 0.01] and abilities of learning and memory [latency to find the platform： （35.8±5.9）, （117.5±11.6） s, P 〈 0.01; distance： （623.1±43.4）, （1 902.3±98.6） cm, P 〈 0.01] as compared with those in the control group. The functional performances in the experimental group at 8 weeks were better than those at two weeks, which were still obviously different from those in the sham-operated group （P 〈 0.05）. ② The HE and Nissl stained brain tissue section showed that there was nerve cell proliferation at the infarcted cortex in the experiment group, the density was higher than that in the control group, plenty of aggregative or scattered cells could be observed at the site where needle was inserted for transplantation, the cells migrated directively towards the area around them, the cerebral vascular walls were wrapped by plenty of cells; In the control group, most of the cortices were destroyed, karyopyknosis and necrosis of neurons were observed, normal nervous tissue structure disappeared induced by edema, only some nerve fibers and glial cells remained.CONCLUSION： The rMSCs transplantation can obviously enhance the motor function and the abilities of learning and memory in rat models of cerebral infarction.

Unmodified autologous stem cells at point of care for chronic myocardial infarction

BACKGROUND Numerous studies investigated cell-based therapies for myocardial infarction(MI).The conflicting results of these studies have established the need for developing innovative approaches for applying cell-based therapy for MI.Experimental studies on animal models demonstrated the potential of fresh,uncultured,unmodified,autologous adipose-derived regenerative cells(UAADRCs)for treating acute MI.In contrast,studies on the treatment of chronic MI(CMI;>4 wk post-MI)with UA-ADRCs have not been published so far.Among several methods for delivering cells to the myocardium,retrograde delivery into a temporarily blocked coronary vein has recently been demonstrated as an effective option.AIM To test the hypothesis that in experimentally-induced chronic myocardial infarction(CMI;>4 wk post-MI)in pigs,retrograde delivery of fresh,uncultured,unmodified,autologous adipose-derived regenerative cells(UA-ADRCs)into a temporarily blocked coronary vein improves cardiac function and structure.METHODS The left anterior descending(LAD)coronary artery of pigs was blocked for 180 min at time point T0.Then,either 18×106 UA-ADRCs prepared at“point of care”or saline as control were retrogradely delivered via an over-the-wire balloon catheter placed in the temporarily blocked LAD vein 4 wk after T0(T1).Effects of cells or saline were assessed by cardiac magnetic resonance(CMR)imaging,late gadolinium enhancement CMR imaging,and post mortem histologic analysis 10 wk after T0(T2).RESULTS Unlike the delivery of saline,delivery of UA-ADRCs demonstrated statistically significant improvements in cardiac function and structure at T2 compared to T1(all values given as mean±SE):Increased mean LVEF(UA-ADRCs group:34.3%±2.9%at T1 vs 40.4±2.6%at T2,P=0.037;saline group:37.8%±2.6%at T1 vs 36.2%±2.4%at T2,P>0.999),increased mean cardiac output(UA-ADRCs group:2.7±0.2 L/min at T1 vs 3.8±0.2 L/min at T2,P=0.002;saline group:3.4±0.3 L/min at T1 vs 3.6±0.3 L/min at T2,P=0.798),increased mean mass of the left ventricle(UA-ADRCs group:55.3±5.0 g at T1 vs 71.3±4.5 g at T2,P<0.001;saline group:63.2±3.4 g at T1 vs 68.4±4.0 g at T2,P=0.321)and reduced mean relative amount of scar volume of the left ventricular wall(UA-ADRCs group:20.9%±2.3%at T1 vs 16.6%±1.2%at T2,P=0.042;saline group:17.6%±1.4%at T1 vs 22.7%±1.8%at T2,P=0.022).CONCLUSION Retrograde cell delivery of UA-ADRCs in a porcine model for the study of CMI significantly improved myocardial function,increased myocardial mass and reduced the formation of scar tissue.