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Philippe Menasche - One of the best experts on this subject based on the ideXlab platform.

  • characterization of the paracrine effects of human skeletal myoblasts transplanted in Infarcted Myocardium
    European Journal of Heart Failure, 2008
    Co-Authors: Maitane Perezilzarbe, Albert Hagège, Onnik Agbulut, Beatriz Pelacho, Cristina Ciorba, Edurne San Joseeneriz, Michel Desnos, Pablo Aranda, Enrique J Andreu, Philippe Menasche
    Abstract:

    Background: The discrepancy between the functional improvements yielded experimentally by skeletal myoblasts (SM) transplanted in Infarcted Myocardium and the paucity of their long-term engraftment has raised the hypothesis of cell-mediated paracrine mechanisms. Methods and results: We analyzed gene expression and growth factors released by undifferentiated human SM (CD56 + ), myotubes (SM cultured until confluence) and fibroblasts-like cells (CD56 � ). Gene expression revealed up-regulation of pro-angiogenic (PGF), antiapoptotics (BAG-1, BCL-2), heart development (TNNT2, TNNC1) and extracellular matrix remodelling (MMP-2, MMP-7) genes in SM. In line with the gene expression profile, the analysis of culture supernatants of SM by ELISA identified the release of growth factors involved in angiogenesis (VEGF, PIGF, angiogenin, angiopoietin, HGF and PDGF-BB) as well as proteases involved in matrix remodelling (MMP2, MMP9 and MMP10) and their inhibitors (TIMPs). Culture of smooth muscle cells (SMC), cardiomyocytes (HL-1) and human umbilical vein endothelial cells (HUVECs) with SM-released conditioned media demonstrated an increased proliferation of HUVEC, SMC and cardiomyocytes (pb0.05) and a decrease in apoptosis of cardiomyocytes (pb0.05). Analysis of nude rats transplanted with human SM demonstrated expression of human-specific MMP-2, TNNI3, CNN3, PGF, TNNT2, PAX7, TGF-β, and IGF-1 1 month after transplant. Conclusions: Our data support the paracrine hypothesis whereby myoblast-secreted factors may contribute to the beneficial effects of myogenic cell transplantation in Infarcted Myocardium.

  • Self-assembling peptide nanofibers and skeletal myoblast transplantation in Infarcted Myocardium.
    Journal of biomedical materials research. Part B Applied biomaterials, 2008
    Co-Authors: Gilbert Dubois, Albert Hagège, Patrick Bruneval, Valérie Bellamy, Séverine Peyrard, Laurent Sabbah, Vincent F. M. Segers, Richard T. Lee, Philippe Menasche
    Abstract:

    Cell transplantation is currently limited by poor graft retention and survival in the postinfarction scar. Because this issue could potentially be addressed by embedding cells in bioinjectable scaffolds and boosting cell survival pathways, we induced a myocardial infarction in 72 rats to assess the effects of different self-assembling peptides with or without platelet-derived growth factor (PDGF-BB) on survival of transplanted skeletal myoblasts. Two weeks after coronary artery ligation, rats were randomized to receive in-scar injections of culture medium (controls, n = 11), self-assembling peptide (RAD16-I) nanofibers (NF, n = 9), skeletal myoblasts (n = 12), or skeletal myoblasts in combination with NF (n = 8). In separate experiments with different self-assembling peptides (RAD16-II), rats received in-scar injections of culture medium (controls, n = 6), skeletal myoblasts (n = 10), PDGF-loaded peptides (n = 7), or skeletal myoblasts (5 x 10(6)) in combination with PDGF-loaded peptides (n = 9). After 1 month, left ventricular function, as assessed by echocardiography, was not improved in either of the experimental groups compared with controls. This correlated with the failure of RAD16-I peptides or PDGF-loaded RAD16-II peptides to improve myoblast survival despite a greater angiogenesis. In vitro experiments confirmed that the number of myoblasts decreased over time when seeded on nanofiber gels. These data suggest that the optimal use of biomaterial scaffolds for survival of transplanted cells will require specific tailoring of the biomaterial to the cell type.

  • skeletal myoblast transplantation through a catheter based coronary sinus approach an effective means of improving function of Infarcted Myocardium
    European Heart Journal, 2005
    Co-Authors: Camille Brasselet, Albert Hagège, Jean-thomas Vilquin, Patrick Bruneval, Claire Carrion, Alvine Bissery, Emmanuel Messas, Miguel Cortes Morichetti, Antoine Lafont, Philippe Menasche
    Abstract:

    Aims This study was designed to assess the functional effects of a transvenous coronary sinus technique of skeletal myoblast delivery in Infarcted Myocardium. Methods and results An anterior myocardial infarction was created percutaneously in 14 sheep. Simultaneously, a muscle biopsy was harvested and expanded. Two weeks later, sheep were instrumented percutaneously with a dedicated catheter incorporating an extendable needle for puncture of the venous wall and, under endovascular ultrasound guidance, a microcatheter was advanced through the needle into the target scar for cell delivery. Following the baseline echocardiographic assessment of left ventricular (LV) function, sheep were randomly allocated to receive four-staged in-scar injections of either autologous cells (n ¼ 7) or culture medium (n ¼ 7). Two months later, LV function was reassessed blindly and hearts were explanted for subsequent histological and immunohistochemical analysis. There were no acute procedural complications. Baseline LV ejection fraction (EF) was significantly lower in transplanted sheep than in controls [38% (35‐48) vs. 51% (38‐55), respectively, P ¼ 0.03; median (range)]. Two months later, LVEF was significantly higher in the transplanted group than in controls [50% (47‐56) vs. 39% (36‐47), respectively, P ¼ 0.002]. Clusters of myoblasts were identified by histology and immunohistochemistry in three of the seven transplanted sheep. Conclusion These data suggest the functional efficacy of the transvenous coronary sinus technique as a less invasive means of cell delivery to Infarcted Myocardium.

  • transplantation of autologous fresh bone marrow into Infarcted Myocardium a word of caution
    Circulation, 2003
    Co-Authors: Alain Bel, Albert Hagège, Patrick Bruneval, Emmanuel Messas, Onnik Agbulut, Patrice Richard, Jane Lyse Samuel, Philippe Menasche
    Abstract:

    Background— As the benefits of extemporaneous transplantation (Tx) of fresh (unfractionated) autologous bone marrow (BM) have been primarily studied in the setting of acute myocardial infarction, we assessed whether this approach could be effective for regenerating chronically Infarcted Myocardium. Methods and Results— Myocardial infarction was created in 18 sheep by ligation of circumflex arterial branches. Three weeks later, BM was aspirated from the iliac crest, washed, labeled with the fluorescent dye Dil and reinjected (mean: 422×10 6 cells in 3 mL) in 10 sites across the Infarcted area through the reopened thoracotomy (n=9). Nine controls received culture medium. Left ventricular (LV) function was assessed before and 2 months after Tx by two-dimensional echocardiography whereas transmural velocity gradients were measured using M-mode tissue Doppler imaging at the center of the Infarcted/grafted area. Formalin-fixed hearts were processed for the detection of grafted cells and angiogenesis. LV ejection fraction deteriorated similarly in the Tx and control groups (from 42±5% to 30±4% and from 40±4% to 31±1%, respectively; P =0.86). Likewise, BM Tx failed to prevent LV dilatation and impairment of the global wall motion score. The decrease in regional systolic velocity gradients (s −1 ) featured a similar pattern (Tx group: from 0.77±0.11 to 0.31±0.07; control group: from 0.73±0.10 to 0.50±0.07; P =0.06). Histologically, there was neither BM tissue engraftment, except for a few scattered Dil-positive macrophages in the Infarcted fibrotic areas nor transdifferentiation of BM cells into endothelial cells. Conclusion— These data caution against the functional efficacy of extemporaneous Tx of fresh unfractionated BM into postinfarction scars.

  • myoblasts transplanted into rat Infarcted Myocardium are functionally isolated from their host
    Proceedings of the National Academy of Sciences of the United States of America, 2003
    Co-Authors: Bertrand Leobon, Philippe Menasche, Jean-thomas Vilquin, Isabelle Garcin, Etienne Audinat, Serge Charpak
    Abstract:

    Survival and differentiation of myogenic cells grafted into Infarcted Myocardium have raised the hope that cell transplantation becomes a new therapy for cardiovascular diseases. The approach was further supported by transplantation of skeletal myoblasts, which was shown to improve cardiac performance in several animal species. Despite the success of myoblast transplantation and its recent trial in human, the mechanism responsible for the functional improvement remains unclear. Here, we used intracellular recordings coupled to video and fluorescence microscopy to establish whether myoblasts, genetically labeled with enhanced GFP and transplanted into rat Infarcted Myocardium, retain excitable and contractile properties, and participate actively to cardiac function. Our results indicate that grafted myoblasts differentiate into peculiar hyperexcitable myotubes with a contractile activity fully independent of neighboring cardiomyocytes. We conclude that mechanisms other than electromechanical coupling between grafted and host cells are involved in the improvement of cardiac function.

Jonathan Leor - One of the best experts on this subject based on the ideXlab platform.

  • intracoronary injection of in situ forming alginate hydrogel reverses left ventricular remodeling after myocardial infarction in swine
    Journal of the American College of Cardiology, 2009
    Co-Authors: Jonathan Leor, David Castel, Shmuel Tuvia, Victor Guetta, Ferenc Manczur, Udi Willenz, Ors Petnehazy, Natali Landa, Micha S Feinberg, Eli Konen
    Abstract:

    Objectives This study sought to determine whether alginate biomaterial can be delivered effectively into the Infarcted Myocardium by intracoronary injection to prevent left ventricular (LV) remodeling early after myocardial infarction (MI). Background Although injectable biomaterials can improve infarct healing and repair, the feasibility and effectiveness of intracoronary injection have not been studied. Methods We prepared a calcium cross-linked alginate solution that undergoes liquid to gel phase transition after deposition in Infarcted Myocardium. Anterior MI was induced in swine by transient balloon occlusion of left anterior descending coronary artery. At 4 days after MI, either alginate solution (2 or 4 ml) or saline was injected selectively into the infarct-related coronary artery. An additional group (n = 19) was treated with incremental volumes of biomaterial (1, 2, and 4 ml) or 2 ml saline and underwent serial echocardiography studies. Results Examination of hearts harvested after injection showed that the alginate crossed the Infarcted leaky vessels and was deposited as hydrogel in the Infarcted tissue. At 60 days, control swine experienced an increase in left ventricular (LV) diastolic area by 44%, LV systolic area by 45%, and LV mass by 35%. In contrast, intracoronary injection of alginate (2 and 4 ml) prevented and even reversed LV enlargement (p Conclusions Intracoronary injection of alginate biomaterial is feasible, safe, and effective. Our findings suggest a new percutaneous intervention to improve infarct repair and prevent adverse remodeling after reperfused MI.

  • human embryonic stem cell transplantation to repair the Infarcted Myocardium
    Heart, 2007
    Co-Authors: Jonathan Leor, Micha S Feinberg, Sharon Gerecht, Smadar Cohen, Liron Miller, Radka Holbova, Anna Ziskind, Michal Shachar, Esther Guetta, Joseph Itskovitzeldor
    Abstract:

    Objective: To test the hypothesis that human embryonic stem cells (hESCs) can be guided to form new Myocardium by transplantation into the normal or Infarcted heart, and to assess the influence of hESC-derived cardiomyocytes (hESCMs) on cardiac function in a rat model of myocardial infarction (MI). Methods: Undifferentiated hESCs (0.5–1×10 6 ), human embryoid bodies (hEBs) (4–8 days; 0.5–1×10 6 ), 0.1 mm pieces of embryonic stem-derived beating myocardial tissue, and phosphate-buffered saline (control) were injected into the normal or Infarcted Myocardium of athymic nude rats (n = 58) by direct injection into the muscle or into preimplanted three-dimensional alginate scaffold. By 2–4 weeks after transplantation, heart sections were examined to detect the human cells and differentiation with fluorescent in situ hybridisation, using DNA probes specific for human sex chromosomes and HLA-DR or HLA-ABC immunostaining. Results: Microscopic examination showed transplanted human cells in the normal, and to a lesser extent in the Infarcted Myocardium (7/7 vs 2/6; p Conclusions: Undifferentiated hESCs and hEBs are not directed to form new Myocardium after transplantation into normal or Infarcted heart and may create teratoma. Nevertheless, this study shows that hESC-derived cardiomyocyte transplantation can attenuate post-MI scar thinning and left ventricular dysfunction.

  • human umbilical cord blood derived cd133 cells enhance function and repair of the Infarcted Myocardium
    Stem Cells, 2006
    Co-Authors: Jonathan Leor, David Castel, Micha S Feinberg, Liron Miller, Radka Holbova, Esther Guetta, Hanan Galski, Iris Bar, Parvin Zarin, Israel M Barbash
    Abstract:

    The use of adult stem cells for myocardial tissue repair might be limited in elderly and sick people because their cells are depleted and exhausted. The present study was conducted to explore the potential of human umbilical cord blood (UCB) CD133+ progenitor cells for myocardial tissue repair in a model of extensive myocardial infarction (MI). CD133+ progenitor cells were isolated from newborn UCB. Cells (1.2–2 × 106) or saline (control) was infused intravenously 7 days after permanent coronary artery ligation in athymic nude rats. Left ventricular (LV) function was assessed before and 1 month after infusion by echocardiography. Tracking of human cells was performed by fluorescent in situ hybridization for human X and Y chromosomes or by immunostaining for HLA-DR or HLA-ABC. One month after delivery, LV fractional shortening improved by 42 ± 17% in cell-treated hearts and decreased by 39 ± 10% in controls (p = .001). Anterior wall thickness decreased significantly in controls but not in treated hearts. Microscopic examination revealed that the UCB cells were able to migrate, colonize, and survive in the Infarcted Myocardium. Human cells were identified near vessel walls and LV cavity and were occasionally incorporated into endothelial cells in six of nine cell-treated animals but not in controls. Scar tissue from cell-treated animals was significantly populated with autologous myofibroblasts as indicated by colocalization of HLA-DR and α-smooth muscle actin staining. In conclusion, the present work suggests that, after MI, intravenous delivery of human UCB-derived CD133+ cells can produce functional recovery by preventing scar thinning and LV systolic dilatation.

  • cellular cardiomyoplasty of cardiac fibroblasts by adenoviral delivery of myod ex vivo an unlimited source of cells for myocardial repair
    Circulation, 2002
    Co-Authors: Sharon Etzion, Micha S Feinberg, Liron Miller, Radka Holbova, Esther Guetta, Robert A Kloner, Israel M Barbash, Parvin Zarin, Laurence H Kedes, Jonathan Leor
    Abstract:

    Background The muscle-specific MyoD family of transcription factors function as master genes that are able to prompt myogenesis in a variety of cells. The purpose of our study was to determine whether MyoD could induce primary cardiac fibroblasts, isolated from Infarcted Myocardium or pericardium, to undergo myogenic conversion in a clinically relevant approach. Methods and Results Primary rat fibroblasts from 7-day-old Infarcted Myocardium or normal pericardium were transfected by an E1/E3-deleted adenoviral vector carrying both a human MyoD cDNA driven by a CMV promoter and a green fluorescent protein (GFP) reporter gene driven by a second CMV promoter. Expression of MyoD caused myogenic differentiation of cultured fibroblasts, as defined by elongation and fusion into multinucleated myotubes, typical cross striation as identified by electron microscopy, and positive immunostaining for sarcomeric actin, fast myosin heavy chain (MHC), and actinin. The myogenic cells (1.5×106) were transplanted into the in...

  • bioengineered cardiac grafts a new approach to repair the Infarcted Myocardium
    Circulation, 2000
    Co-Authors: Jonathan Leor, Sharon Aboulafiaetzion, Ayelet Dar, Lilia Shapiro, Israel M Barbash, Alexander Battler, Yosef Granot, Smadar Cohen
    Abstract:

    Background—The Myocardium is unable to regenerate because cardiomyocytes cannot replicate after injury. The heart is therefore an attractive target for tissue engineering to replace Infarcted Myocardium and enhance cardiac function. We tested the feasibility of bioengineering cardiac tissue within novel 3-dimensional (3D) scaffolds. Methods and Results—We isolated and grew fetal cardiac cells within 3D porous alginate scaffolds. The cell constructs were cultured for 4 days to evaluate viability and morphology before implantation. Light microscopy revealed that within 2 to 3 days in culture, the dissociated cardiac cells form distinctive, multicellular contracting aggregates within the scaffold pores. Seven days after myocardial infarction, rats were randomized to biograft implantation (n=6) or sham-operation (n=6) into the myocardial scar. Echocardiography study was performed before and 65±5 days after implantation to assess left ventricular (LV) remodeling and function. Hearts were harvested 9 weeks afte...

Yigang Wang - One of the best experts on this subject based on the ideXlab platform.

  • reduced collagen deposition in Infarcted Myocardium facilitates induced pluripotent stem cell engraftment and angiomyogenesis for improvement of left ventricular function
    Journal of the American College of Cardiology, 2011
    Co-Authors: Bo Dai, Muhammad Ashraf, Wei Huang, Ronald W Millard, Mei Hua Gao, Kirk H Hammond, Donald R Menick, Yigang Wang
    Abstract:

    Objectives The purpose of this study was to assess the effect of scar tissue composition on engraftment of progenitor cells into Infarcted Myocardium. Background Scar tissue formation after myocardial infarction creates a barrier that severely compromises tissue regeneration, limiting potential functional recovery. Methods In vitro: A tricell patch (Tri-P) was created from peritoneum seeded and cultured with induced pluripotent stem cell–derived cardiomyocytes, endothelial cells, and mouse embryonic fibroblasts. The expression of fibrosis-related molecules from mouse embryonic fibroblasts and Infarcted heart was measured by Western blot and quantitative reverse transcriptase polymerase chain reaction. In vivo: A Tri-P was affixed over the entire Infarcted area 7 days after myocardial infarction in mice overexpressing adenylyl cyclase 6 (AC6). Engraftment efficiency of progenitor cells in hearts of AC6 mice was compared with that of control wild-type (WT) mice using a combination of in vivo bioluminescence imaging, post-mortem ex vivo tissue analysis, and the number of green fluorescent protein–positive cells. Echocardiography of left ventricular (LV) function was performed weekly. Hearts were harvested for analysis 4 weeks after Tri-P application. Mouse embryonic fibroblasts were stimulated with forskolin before an anoxia/reoxygenation protocol. Fibrosis-related molecules were analyzed . Results In AC6 mice, Infarcted hearts treated with Tri-P showed significantly higher bioluminescence imaging intensity and numbers of green fluorescent protein–positive cells than in WT mice. LV function improved progressively in AC6 mice from weeks 2 to 4 and was associated with reduced LV fibrosis. Conclusions Application of a Tri-P in AC6 mice resulted in significantly higher induced pluripotent stem cell engraftment accompanied by angiomyogenesis in the Infarcted area and improvement in LV function.

  • over expression of cxcr4 on mesenchymal stem cells augments myoangiogenesis in the Infarcted Myocardium
    Journal of Molecular and Cellular Cardiology, 2008
    Co-Authors: Dongsheng Zhang, Zeeshan Pasha, Tiemin Zhao, Muhammad Ashraf, Xiaoyang Zhou, Guochang Fan, Yi Zhu, Yigang Wang
    Abstract:

    Bone marrow mesenchymal stem cells (MSCs) participate in myocardial repair following myocardial infarction. However, their in vivo reparative capability is limited due to lack of their survival in the Infarcted Myocardium. To overcome this limitation, we genetically engineered male rat MSCs overexpressing CXCR4 in order to maximize the effect of stromal cell-derived factor-1alpha (SDF-1alpha) for cell migration and regeneration. MSCs were isolated from adult male rats and cultured. Adenoviral transduction was carried out to over-express either CXCR4/green fluorescent protein (Ad-CXCR4/GFP) or Ad-null/GFP alone (control). Flow cytometry was used to identify and isolate GFP/CXCR4 over-expressing MSCs for transplantation. Female rats were assigned to one of four groups (n=8 each) to receive GFP-transduced male MSCs (2 x 10(6)) via tail vein injection 3 days after ligation of the left anterior descending (LAD) coronary artery: GFP-transduced MSCs (Ad-null/GFP-MSCs, group 1) or MSCs over-expressing CXCR4/GFP (Ad-CXCR4/GFP-MSCs, group 2), or Ad-CXCR4/GFP-MSCs plus SDF-1alpha (50 ng/microl) (Ad-CXCR4/GFP-MSCs/SDF-1alpha, group 3), or Ad-miRNA targeting CXCR4 plus SDF-1alpha (Ad-miRNA/GFP-MSCs+SDF-1alpha treatment, group 4). Cardiodynamic data were obtained 4 weeks after induction of regional myocardial infarction (MI) using echocardiography after which hearts were harvested for immunohistochemical studies. The migration of GFP and Y-chromosome positive cells increased significantly in the peri- and infarct areas of groups 2 and 3 compared to control group (p<0.05), or miRNA-CXCR4 group (p<0.01). The number of CXCR4 positive cells in groups 2, 3 was intimately associated with angiogenesis and myogenesis. MSCs engraftment was blocked by pretreatment with miRNA (group 4). Cardiac function was significantly improved in rats receiving MSCs over-expressing CXCR4 alone or with SDF-1alpha. The up-regulation of matrix metalloproteinases (MMPs) by CXCR4 overexpressing MSCs perhaps facilitated their engraftment in the collagenous tissue of the Infarcted area. CXCR4 over-expression led to enhance in vivo mobilization and engraftment of MSCs into ischemic area where these cells promoted neomyoangiogenesis and alleviated early signs of left ventricular remodeling.

  • over expression of cxcr4 on mesenchymal stem cells augments myoangiogenesis in the Infarcted Myocardium
    Journal of Molecular and Cellular Cardiology, 2008
    Co-Authors: Dongsheng Zhang, Zeeshan Pasha, Tiemin Zhao, Muhammad Ashraf, Xiaoyang Zhou, Meifeng Xu, Yigang Wang
    Abstract:

    Abstract Bone marrow mesenchymal stem cells (MSCs) participate in myocardial repair following myocardial infarction. However, their in vivo reparative capability is limited due to lack of their survival in the Infarcted Myocardium. To overcome this limitation, we genetically engineered male rat MSCs overexpressing CXCR4 in order to maximize the effect of stromal cell-derived factor-1α (SDF-1α) for cell migration and regeneration. MSCs were isolated from adult male rats and cultured. Adenoviral transduction was carried out to over-express either CXCR4/green fluorescent protein (Ad-CXCR4/GFP) or Ad-null/GFP alone (control). Flow cytometry was used to identify and isolate GFP/CXCR4 over-expressing MSCs for transplantation. Female rats were assigned to one of four groups ( n  = 8 each) to receive GFP-transduced male MSCs (2 × 10 6 ) via tail vein injection 3 days after ligation of the left anterior descending (LAD) coronary artery: GFP-transduced MSCs (Ad-null/GFP-MSCs, group 1) or MSCs over-expressing CXCR4/GFP (Ad-CXCR4/GFP-MSCs, group 2), or Ad-CXCR4/GFP-MSCs plus SDF-1α (50 ng/μl) (Ad-CXCR4/GFP-MSCs/SDF-1α, group 3), or Ad-miRNA targeting CXCR4 plus SDF-1α (Ad-miRNA/GFP-MSCs + SDF-1α treatment, group 4). Cardiodynamic data were obtained 4 weeks after induction of regional myocardial infarction (MI) using echocardiography after which hearts were harvested for immunohistochemical studies. The migration of GFP and Y-chromosome positive cells increased significantly in the peri- and infarct areas of groups 2 and 3 compared to control group ( p p in vivo mobilization and engraftment of MSCs into ischemic area where these cells promoted neomyoangiogenesis and alleviated early signs of left ventricular remodeling.

  • preconditioning enhances cell survival and differentiation of stem cells during transplantation in Infarcted Myocardium
    Cardiovascular Research, 2007
    Co-Authors: Zeeshan Pasha, Yigang Wang, Riazuddin Sheikh, Dongsheng Zhang, Tiemin Zhao, Muhammad Ashraf
    Abstract:

    Aims We hypothesized that preconditioning (PC) with stromal-derived factor 1 alpha (SDF-1) significantly enhances cell survival, proliferation, and engraftment of bone marrow-derived mesenchymal stem cells (MSCs) via SDF-1/CXCR4 signaling. Methods and results MSCs were cultured and then incubated in medium for 60 min without SDF-1 (control group) or with SDF-1 0.05 µg/mL (SDF-1 group) or CXCR4-selective antagonist, AMD 3100 (AMD) (5 µg/mL, AMD group) or SDF-1 and AMD (0.05 µg/mL, 5 µg/mL, respectively, SDF-1+AMD group). MSCs were treated for 60 min, washed in normal medium, and then exposed to H2O2 (100 µmol/L) for 60 min to determine the effects of various treatments on cell injury, viability, and proliferation. For in vivo studies, rats were grouped ( n = 6) after left anterior descending coronary artery ligation to receive 20 µL Dulbecco’s modified Eagle’s medium without cells or with 5 × 105 non-preconditioned MSCs (control group), SDF-1 preconditioned MSCs (SDF-1 group), AMD (AMD group), or MSCs treated with SDF-1 plus AMD (SDF-1+AMD group). Heart function, infarct size, fibrosis, and MSC proliferation and differentiation in Infarcted Myocardium were determined after 4 weeks. In vitro data showed a marked increase in cell viability and proliferation following SDF-1 PC. In vivo data in preconditioned group showed a robust cell proliferation, reduction in infarct size and fibrosis, and significant improvement in cardiac function. Effects of SDF-1 PC were abrogated by CXCR4 antagonist. Conclusion We conclude that PC with the chemokine SDF-1 suppresses MSCs apoptosis, enhances their survival, engraftment, and vascular density, and improves myocardial function via SDF/CXCR4 signaling. Chemokine PC is a novel approach for enhancing stem cell survival and regeneration of Infarcted Myocardium.

Muhammad Ashraf - One of the best experts on this subject based on the ideXlab platform.

  • abstract 17802 ips cells derived cardiac progenitors induce dramatic cardiac regeneration and improve function by cxcr4 signaling pathway in Infarcted Myocardium
    Circulation, 2014
    Co-Authors: Zeshan Pasha, Romana Saeed, Muhammad Ashraf
    Abstract:

    Background: The participation of endogenous cardiac stem/progenitor cells is limited in restoring cardiac structure and function in the ischemic Myocardium which is further aggravated by poor survival and propagation of transplanted stem cells of different origin in the Infarcted heart. The goal of this study was to explore the survival and engraftability of newly discovered induced pluripotent stem cells (IPS) in the Myocardium following infarction (MI). Methods and Results: Integration free iPS were generated from myoblasts and characterized. Cardiac progenitors (CPs) were created by treatment with a small molecule. CPs proliferation was assessed by BrdU labeling; Differentiation by both RT-PCR and immunofluorescent staining for cardiac markers Nkx2.5, actinin, and -MHC. Gene expression profiling was performed using Affymetrix array. In vivo studies were carried out by injecting CPs or nontreated IPS (3x105), into mouse model of permanent LAD. Echocardiography, histological parameters, TUNEL assay and capillary vessel density were measured 6 weeks post transplantation. Treatment of IPS with a small molecule upregulated Nkx2.5 and maintained up to 4 weeks (p Conclusion: This study provides a novel strategy for generating CPs and their enhanced survival, engraftment and differentiation with the treatment of cardiogenic small molecule post transplantation in the Infarcted Myocardium through CXCR4 signaling pathway.

  • reduced collagen deposition in Infarcted Myocardium facilitates induced pluripotent stem cell engraftment and angiomyogenesis for improvement of left ventricular function
    Journal of the American College of Cardiology, 2011
    Co-Authors: Bo Dai, Muhammad Ashraf, Wei Huang, Ronald W Millard, Mei Hua Gao, Kirk H Hammond, Donald R Menick, Yigang Wang
    Abstract:

    Objectives The purpose of this study was to assess the effect of scar tissue composition on engraftment of progenitor cells into Infarcted Myocardium. Background Scar tissue formation after myocardial infarction creates a barrier that severely compromises tissue regeneration, limiting potential functional recovery. Methods In vitro: A tricell patch (Tri-P) was created from peritoneum seeded and cultured with induced pluripotent stem cell–derived cardiomyocytes, endothelial cells, and mouse embryonic fibroblasts. The expression of fibrosis-related molecules from mouse embryonic fibroblasts and Infarcted heart was measured by Western blot and quantitative reverse transcriptase polymerase chain reaction. In vivo: A Tri-P was affixed over the entire Infarcted area 7 days after myocardial infarction in mice overexpressing adenylyl cyclase 6 (AC6). Engraftment efficiency of progenitor cells in hearts of AC6 mice was compared with that of control wild-type (WT) mice using a combination of in vivo bioluminescence imaging, post-mortem ex vivo tissue analysis, and the number of green fluorescent protein–positive cells. Echocardiography of left ventricular (LV) function was performed weekly. Hearts were harvested for analysis 4 weeks after Tri-P application. Mouse embryonic fibroblasts were stimulated with forskolin before an anoxia/reoxygenation protocol. Fibrosis-related molecules were analyzed . Results In AC6 mice, Infarcted hearts treated with Tri-P showed significantly higher bioluminescence imaging intensity and numbers of green fluorescent protein–positive cells than in WT mice. LV function improved progressively in AC6 mice from weeks 2 to 4 and was associated with reduced LV fibrosis. Conclusions Application of a Tri-P in AC6 mice resulted in significantly higher induced pluripotent stem cell engraftment accompanied by angiomyogenesis in the Infarcted area and improvement in LV function.

  • over expression of cxcr4 on mesenchymal stem cells augments myoangiogenesis in the Infarcted Myocardium
    Journal of Molecular and Cellular Cardiology, 2008
    Co-Authors: Dongsheng Zhang, Zeeshan Pasha, Tiemin Zhao, Muhammad Ashraf, Xiaoyang Zhou, Meifeng Xu, Yigang Wang
    Abstract:

    Abstract Bone marrow mesenchymal stem cells (MSCs) participate in myocardial repair following myocardial infarction. However, their in vivo reparative capability is limited due to lack of their survival in the Infarcted Myocardium. To overcome this limitation, we genetically engineered male rat MSCs overexpressing CXCR4 in order to maximize the effect of stromal cell-derived factor-1α (SDF-1α) for cell migration and regeneration. MSCs were isolated from adult male rats and cultured. Adenoviral transduction was carried out to over-express either CXCR4/green fluorescent protein (Ad-CXCR4/GFP) or Ad-null/GFP alone (control). Flow cytometry was used to identify and isolate GFP/CXCR4 over-expressing MSCs for transplantation. Female rats were assigned to one of four groups ( n  = 8 each) to receive GFP-transduced male MSCs (2 × 10 6 ) via tail vein injection 3 days after ligation of the left anterior descending (LAD) coronary artery: GFP-transduced MSCs (Ad-null/GFP-MSCs, group 1) or MSCs over-expressing CXCR4/GFP (Ad-CXCR4/GFP-MSCs, group 2), or Ad-CXCR4/GFP-MSCs plus SDF-1α (50 ng/μl) (Ad-CXCR4/GFP-MSCs/SDF-1α, group 3), or Ad-miRNA targeting CXCR4 plus SDF-1α (Ad-miRNA/GFP-MSCs + SDF-1α treatment, group 4). Cardiodynamic data were obtained 4 weeks after induction of regional myocardial infarction (MI) using echocardiography after which hearts were harvested for immunohistochemical studies. The migration of GFP and Y-chromosome positive cells increased significantly in the peri- and infarct areas of groups 2 and 3 compared to control group ( p p in vivo mobilization and engraftment of MSCs into ischemic area where these cells promoted neomyoangiogenesis and alleviated early signs of left ventricular remodeling.

  • over expression of cxcr4 on mesenchymal stem cells augments myoangiogenesis in the Infarcted Myocardium
    Journal of Molecular and Cellular Cardiology, 2008
    Co-Authors: Dongsheng Zhang, Zeeshan Pasha, Tiemin Zhao, Muhammad Ashraf, Xiaoyang Zhou, Guochang Fan, Yi Zhu, Yigang Wang
    Abstract:

    Bone marrow mesenchymal stem cells (MSCs) participate in myocardial repair following myocardial infarction. However, their in vivo reparative capability is limited due to lack of their survival in the Infarcted Myocardium. To overcome this limitation, we genetically engineered male rat MSCs overexpressing CXCR4 in order to maximize the effect of stromal cell-derived factor-1alpha (SDF-1alpha) for cell migration and regeneration. MSCs were isolated from adult male rats and cultured. Adenoviral transduction was carried out to over-express either CXCR4/green fluorescent protein (Ad-CXCR4/GFP) or Ad-null/GFP alone (control). Flow cytometry was used to identify and isolate GFP/CXCR4 over-expressing MSCs for transplantation. Female rats were assigned to one of four groups (n=8 each) to receive GFP-transduced male MSCs (2 x 10(6)) via tail vein injection 3 days after ligation of the left anterior descending (LAD) coronary artery: GFP-transduced MSCs (Ad-null/GFP-MSCs, group 1) or MSCs over-expressing CXCR4/GFP (Ad-CXCR4/GFP-MSCs, group 2), or Ad-CXCR4/GFP-MSCs plus SDF-1alpha (50 ng/microl) (Ad-CXCR4/GFP-MSCs/SDF-1alpha, group 3), or Ad-miRNA targeting CXCR4 plus SDF-1alpha (Ad-miRNA/GFP-MSCs+SDF-1alpha treatment, group 4). Cardiodynamic data were obtained 4 weeks after induction of regional myocardial infarction (MI) using echocardiography after which hearts were harvested for immunohistochemical studies. The migration of GFP and Y-chromosome positive cells increased significantly in the peri- and infarct areas of groups 2 and 3 compared to control group (p<0.05), or miRNA-CXCR4 group (p<0.01). The number of CXCR4 positive cells in groups 2, 3 was intimately associated with angiogenesis and myogenesis. MSCs engraftment was blocked by pretreatment with miRNA (group 4). Cardiac function was significantly improved in rats receiving MSCs over-expressing CXCR4 alone or with SDF-1alpha. The up-regulation of matrix metalloproteinases (MMPs) by CXCR4 overexpressing MSCs perhaps facilitated their engraftment in the collagenous tissue of the Infarcted area. CXCR4 over-expression led to enhance in vivo mobilization and engraftment of MSCs into ischemic area where these cells promoted neomyoangiogenesis and alleviated early signs of left ventricular remodeling.

  • preconditioning enhances cell survival and differentiation of stem cells during transplantation in Infarcted Myocardium
    Cardiovascular Research, 2007
    Co-Authors: Zeeshan Pasha, Yigang Wang, Riazuddin Sheikh, Dongsheng Zhang, Tiemin Zhao, Muhammad Ashraf
    Abstract:

    Aims We hypothesized that preconditioning (PC) with stromal-derived factor 1 alpha (SDF-1) significantly enhances cell survival, proliferation, and engraftment of bone marrow-derived mesenchymal stem cells (MSCs) via SDF-1/CXCR4 signaling. Methods and results MSCs were cultured and then incubated in medium for 60 min without SDF-1 (control group) or with SDF-1 0.05 µg/mL (SDF-1 group) or CXCR4-selective antagonist, AMD 3100 (AMD) (5 µg/mL, AMD group) or SDF-1 and AMD (0.05 µg/mL, 5 µg/mL, respectively, SDF-1+AMD group). MSCs were treated for 60 min, washed in normal medium, and then exposed to H2O2 (100 µmol/L) for 60 min to determine the effects of various treatments on cell injury, viability, and proliferation. For in vivo studies, rats were grouped ( n = 6) after left anterior descending coronary artery ligation to receive 20 µL Dulbecco’s modified Eagle’s medium without cells or with 5 × 105 non-preconditioned MSCs (control group), SDF-1 preconditioned MSCs (SDF-1 group), AMD (AMD group), or MSCs treated with SDF-1 plus AMD (SDF-1+AMD group). Heart function, infarct size, fibrosis, and MSC proliferation and differentiation in Infarcted Myocardium were determined after 4 weeks. In vitro data showed a marked increase in cell viability and proliferation following SDF-1 PC. In vivo data in preconditioned group showed a robust cell proliferation, reduction in infarct size and fibrosis, and significant improvement in cardiac function. Effects of SDF-1 PC were abrogated by CXCR4 antagonist. Conclusion We conclude that PC with the chemokine SDF-1 suppresses MSCs apoptosis, enhances their survival, engraftment, and vascular density, and improves myocardial function via SDF/CXCR4 signaling. Chemokine PC is a novel approach for enhancing stem cell survival and regeneration of Infarcted Myocardium.

Nikolaos G. Frangogiannis - One of the best experts on this subject based on the ideXlab platform.

  • opposing actions of fibroblast and cardiomyocyte smad3 signaling in the Infarcted Myocardium
    Circulation, 2017
    Co-Authors: Ping Kong, Bijun Chen, Arti V Shinde, Ilaria Russo, Amit Saxena, Simon J Conway, Jonathan M Graff, Nikolaos G. Frangogiannis
    Abstract:

    Background —Transforming Growth Factor (TGF)-βs regulate a wide range of cellular responses by activating Smad-dependent and Smad-independent cascades. In the Infarcted heart, Smad3 signaling is activated in both cardiomyocytes and interstitial cells. We hypothesized that cell-specific actions of Smad3 regulate repair and remodeling in the Infarcted Myocardium. Methods —In order to dissect cell-specific Smad3 actions in myocardial infarction, we generated mice with Smad3 loss in activated fibroblasts, or in cardiomyocytes. Cardiac function was assessed following reperfused or non-reperfused infarction using echocardiography. The effects of cell-specific Smad3 loss on the Infarcted heart were studied using histological studies, assessment of protein and gene expression levels. In vitro, we studied Smad-dependent and Smad-independent actions in isolated cardiac fibroblasts. Results —Mice with fibroblast-specific Smad3 loss had accentuated adverse remodeling following reperfused infarction, and exhibited an increased incidence of late rupture following non-reperfused infarction. The consequences of fibroblast-specific Smad3 loss were not due to effects on acute infarct size, but were associated with unrestrained fibroblast proliferation, impaired scar remodeling, reduced fibroblast-derived collagen synthesis, and perturbed alignment of myofibroblast arrays in the infarct. Polarized light microscopy in sirius red-stained sections demonstrated that the changes in fibroblast morphology were associated with perturbed organization of the collagenous matrix in the Infarcted area. In contrast, α-SMA expression by infarct myofibroblasts was not affected by Smad3 loss. Smad3 critically regulated fibroblast function, activating integrin-mediated NADPH oxidase (NOX)-2 expression. Smad3 loss in cardiomyocytes attenuated post-infarction remodeling and dysfunction. Cardiomyocyte-specific Smad3 loss did not affect acute infarct size, but was associated with attenuated cardiomyocyte apoptosis in the remodeling Myocardium, accompanied by decreased myocardial NOX2 levels, reduced nitrosative stress, and lower matrix metalloproteinase-2 expression. Conclusions —In healing myocardial infarction, myofibroblast- and cardiomyocyte-specific activation of Smad3 has contrasting functional outcomes that may involve activation of an integrin/reactive oxygen axis.

  • the role of transforming growth factor tgf β in the Infarcted Myocardium
    Journal of Thoracic Disease, 2017
    Co-Authors: Nikolaos G. Frangogiannis
    Abstract:

    The adult mammalian heart has negligible regenerative capacity. Following myocardial infarction, sudden necrosis of cardiomyocytes triggers an intense inflammatory reaction that clears the wound from dead cells and matrix debris, while activating a reparative program. A growing body of evidence suggests that members of the transforming growth factor (TGF)-β family critically regulate the inflammatory and reparative response following infarction. Although all three TGF-β isoforms (TGF-β1, -β2 and -β3) are markedly upregulated in the Infarcted Myocardium, information on isoform-specific actions is limited. Experimental studies have suggested that TGF-β exerts a wide range of actions on cardiomyocytes, fibroblasts, immune cells, and vascular cells. The findings are often conflicting, reflecting the context-dependence of TGF-β-mediated effects; conclusions are often based exclusively on in vitro studies and on associative evidence. TGF-β has been reported to modulate cardiomyocyte survival responses, promote monocyte recruitment, inhibit macrophage pro-inflammatory gene expression, suppress adhesion molecule synthesis by endothelial cells, promote myofibroblast conversion and extracellular matrix synthesis, and mediate both angiogenic and angiostatic effects. This review manuscript discusses our understanding of the cell biological effects of TGF-β in myocardial infarction. We discuss the relative significance of downstream TGF-β-mediated Smad-dependent and -independent pathways, and the risks and challenges of therapeutic TGF-β targeting. Considering the high significance of TGF-β-mediated actions in vivo, study of cell-specific effects and dissection of downstream signaling pathways are needed in order to design safe and effective therapeutic approaches.

  • immune cells in repair of the Infarcted Myocardium
    Microcirculation, 2017
    Co-Authors: Bijun Chen, Nikolaos G. Frangogiannis
    Abstract:

    The immune system plays a critical role in both repair and remodeling of the Infarcted Myocardium. Danger signals released by dying cardiomyocytes mobilize, recruit, and activate immune cells, triggering an inflammatory reaction. CXC chemokines containing the ELR motif attract neutrophils, while CC chemokines mediate recruitment of mononuclear cell subpopulations, contributing to clearance of the infarct from dead cells and matrix debris. Immune cell subsets also participate in suppression and containment of the postinfarction inflammatory response by secreting anti-inflammatory mediators, such as IL-10 and TGF-β. As proinflammatory signaling is suppressed, macrophage subpopulations, mast cells and lymphocytes, activate fibrogenic and angiogenic responses, contributing to scar formation. In the viable remodeling Myocardium, chronic activation of immune cells may promote fibrosis and hypertrophy. This review discusses the role of immune cells in repair and remodeling of the Infarcted Myocardium. Understanding the role of immune cells in myocardial infarction is critical for the development of therapeutic strategies aimed at protecting the Infarcted heart from adverse remodeling. Moreover, modulation of immune cell phenotype may be required in order to achieve the visionary goal of myocardial regeneration.

  • regulatory t cells are recruited in the Infarcted mouse Myocardium and may modulate fibroblast phenotype and function
    American Journal of Physiology-heart and Circulatory Physiology, 2014
    Co-Authors: Amit Saxena, Marcin Dobaczewski, Nikolaos G. Frangogiannis, Wei Chen, Vikrant Rai, Zaffar Haque
    Abstract:

    Regulatory T cells (Tregs) play a pivotal role in suppressing immune responses regulating behavior and gene expression in effector T cells, macrophages, and dendritic cells. Tregs infiltrate the Infarcted Myocardium; however, their role the inflammatory and reparative response after myocardial infarction remains poorly understood. We used FoxP3EGFP reporter mice to study Treg trafficking in the Infarcted heart and examined the effects of Treg depletion on postinfarction remodeling using an anti-CD25 antibody. Moreover, we investigated the in vitro effects of Tregs on cardiac fibroblast phenotype and function. Low numbers of Tregs infiltrated the Infarcted Myocardium after 24–72 h of reperfusion. Treg depletion had no significant effects on cardiac dysfunction and scar size after reperfused myocardial infarction but accelerated ventricular dilation and accentuated apical remodeling. Enhanced myocardial dilation in Treg-depleted animals was associated with increased expression of chemokine (C-C motif) ligand 2 and accentuated macrophage infiltration. In vitro, Tregs modulated the cardiac fibroblast phenotype, reducing expression of α-smooth muscle actin, decreasing expression of matrix metalloproteinase-3, and attenuating contraction of fibroblast-populated collagen pads. Our findings suggest that endogenous Tregs have modest effects on the inflammatory and reparative response after myocardial infarction. However, the anti-inflammatory and matrix-preserving properties of Tregs may suggest a role for Treg-based cell therapy in the attenuation of adverse postinfarction remodeling.

  • cxcr3 independent actions of the cxc chemokine cxcl10 in the Infarcted Myocardium and in isolated cardiac fibroblasts are mediated through proteoglycans
    Cardiovascular Research, 2014
    Co-Authors: Amit Saxena, Marcin Dobaczewski, Nikolaos G. Frangogiannis, Marcin Bujak, Olga Frunza, Carlos Gonzalezquesada, Craig Gerard
    Abstract:

    Aims The CXC chemokine CXCL10 is up-regulated in the Infarcted Myocardium and limits cardiac fibrosis by inhibiting growth factor-mediated fibroblast migration. CXCL10 signals by binding to its receptor CXCR3; however, recently CXCR3-independent CXCL10 actions have been suggested. Our study explores the role of CXCR3 signalling in myocardial infarction and investigates its involvement in mediating the anti-fibrotic effects of CXCL10. Methods and results Wild-type and CXCR3 null mice underwent reperfused infarction protocols. CXCL10 was markedly induced in the infarct; in contrast, expression of the other two CXCR3 ligands, CXCL9 and CXCL11 was extremely low. CXCR3 loss did not affect scar size, geometric ventricular remodelling, collagen deposition, and systolic dysfunction of the Infarcted heart. CXCR3 null mice had increased peak neutrophil recruitment and delayed myofibroblast infiltration in the Infarcted heart, but exhibited comparable myocardial expression of pro-inflammatory cytokines and chemokines. In vitro , CXCL10 did not modulate Transforming Growth Factor (TGF)-β signalling, but inhibited basic fibroblast growth factor (bFGF)-induced cardiac fibroblast migration in both wild-type and CXCR3 null cells. Treatment of fibroblasts with heparinase and chondroitinase to cleave glycosaminoglycan chains abrogated the inhibitory effects of CXCL10 on cell migration. Conclusion CXCR3 signalling does not critically regulate cardiac remodelling and dysfunction following myocardial infarction. The anti-fibrotic effects of CXCL10 in the healing infarct and in isolated cardiac fibroblasts are CXCR3-independent and may be mediated through proteoglycan signalling. Thus, administration of CXCR3-defective forms of CXCL10 may be an effective anti-fibrotic strategy in the remodelling Myocardium without activating a potentially injurious, CXCR3-driven T cell response.