Survey
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Am J Physiol Heart Circ Physiol 288: H2557–H2567, 2005; doi:10.1152/ajpheart.01215.2004. Invited Review Bone marrow stem cell transplantation for cardiac repair Husnain Kh Haider and Muhammad Ashraf Department of Pathology and Laboratory of Medicine, University of Cincinnati, Cincinnati, Ohio myocardial infarction; cardiomyocyte; plasticity; transdifferentiation in both small and large animal models and phase 1 clinical studies in humans have shown the promise of bone marrow and bone marrow-derived stem cells in the treatment of diseased myocardium (111). The secret of this promise lies in the remarkable potential of bone marrow stem cells to undergo multilineage differentiation in general and cardiomyogenic potential in particular (66, 108). Bone marrow consists of a nonhomogeneous population of cells composed of various lineages with differing abilities. The hematopoietic stem cell (HSC) fraction of the bone marrow is responsible for the production of ⬎95% of the body’s blood cells. They have an extensive capacity of self-renewal. Recent reports (27, 65) have shown that HSC may also have the potential to differentiate into other lineages of cells, including their competence to attain the cardiac phenotype. The work of Matsuzaki and colleagues (81) suggests high-marrow seeding efficiency as a specific characteristic of primitive HSC in addition to their self-renewal and multipotent capacity. They have demonstrated a high “homing to niche” capacity of these cells. Over a long period of time, CD34, a cell surface molecule that is expressed on 1–3% of bone marrow cells, has been used as a convenient positive selection marker for HSC (94). However, several reports have raised serious questions about CD34 expression on hematopoietic cells in the mouse (36). Sato and colleagues (112) have shown that CD34 expression in murine HSC reflects the activation state, and this may be so in humans. Moreover, the presence of human CD34⫺ HSC has been reported as being more immature than CD34⫹ stem cells (15). Consequently, AC133 is being used as an alternative selection marker to CD34 antigen. The rationale to use purified THE RESULTS OF STUDIES AC133⫹ cells is to avoid injection of a large number of leukocytes and their progenitors, which have limited plasticity and the presence of which in large numbers may give rise to an unwanted inflammatory response at the site of the graft (152). On the other hand, the non-HSC fraction is mainly composed of mesenchymal stem cells. They are clonogenic and possess the potential to develop into mature cells that produce fat, cartilage, bone, tendons, and muscle (108). They can be isolated from bone marrow and can easily be expanded in an in vitro cell culture without compromising their stem cell capabilities (86). Because of the ease of the method of their purification and multipotent nature, they have been extensively studied in both experimental and clinical settings. There is no universal surface marker for the identification of mesenchymal stem cells. They are negative for HSC markers CD31, CD34, and CD45 and express on their surface CD44, CD90, CD105, CD106, and CD166 (78). Besides, they have been reported to express T cell receptor components that enable them to remain in a state of readiness to enter various pathways of differentiation upon induction (158). Mesenchymal stem cells with similar potential have also been isolated from tissues other than bone marrow including peripheral blood and umbilical cord blood (61). Kawada et al. (59) have recently shown that CD34⫺ nonhematopoietic bone marrow mesenchymal stem cells can differentiate into cardiomyocytes. The heterogeneous mononuclear fraction of the bone marrow (BMMNC) is the most promising and extensively studied stem cell population for cellular cardiomyoplasty (24, 47, 54, 56). Besides, CD117 and Sca-1⫹ cells have also been focused to assess their cardiomyogenic potential (72, 73, 76, 80, 152). MALLEABLE NATURE OF BONE MARROW STEM CELLS Address for reprint requests and other correspondence: H. Kh Haider, Dept. of Pathology and Laboratory of Medicine, 231-Albert Sabinway, Univ. of Cincinnati, Cinncinati, OH 45267-0529 (E-mail: [email protected]). http://www.ajpheart.org Intravenous administration of bone marrow-derived mesenchymal stem cells leads to their preferential migration to the 0363-6135/05 $8.00 Copyright © 2005 the American Physiological Society H2557 Downloaded from http://ajpheart.physiology.org/ by 10.220.32.247 on April 29, 2017 Haider, Kh Husnain, and Muhammad Ashraf. Bone marrow stem cell transplantation for cardiac repair. Am J Physiol Heart Circ Physiol 288: H2557– H2567, 2005; doi:10.1152/ajpheart.01215.2004.—Cardiomyocytes respond to physiological or pathological stress only by hypertrophy and not by an increase in the number of functioning cardiomyocytes. However, recent evidence suggests that adult cardiomyocytes have the ability, albeit limited, to divide to compensate for the cardiomyocyte loss in the event of myocardial injury. Similarly, the presence of stem cells in the myocardium is a good omen. Their activation to participate in the repair process is, however, hindered by some as-yet-undetermined biological impediments. The rationale behind the use of adult stem cell transplantation is to supplement the inadequacies of the intrinsic repair mechanism of the heart and compensate for the cardiomyocyte loss in the event of injury. Various cell types including embryonic, fetal, and adult cardiomyocytes, smooth muscle cells, and stable cell lines have been used to augment the declining cardiomyocyte number and cardiac function. More recently, the focus has been shifted to the use of autologous skeletal myoblasts and bone marrow-derived stem cells. This review is a synopsis of some interesting aspects of the fast-emerging field of bone marrowderived stem cell therapy for cardiac repair. Invited Review H2558 BONE MARROW STEM CELLS FOR HEART mechanisms, the consensus is on transdifferentiation of bone marrow cells into cardiomyocytes and endothelial cell phenotypes and angiogenesis (Tables 1–3). The ability of bone marrow-derived stem cells to break the barriers of lineage restriction and transdifferentiate to form different tissue cells are being extensively investigated (6, 37, 46, 53, 133, 135). A series of recent experiments have challenged the long-standing dogma of lineage restriction. The multipotential nature of bone marrow stem cells to transdifferentiate into various lineages has been shown in vitro (18, 21, 98, 137, 148, 151). Similar results have also been corroborated in vivo (9, 69, 95, 157). The underlying principle to these observations is that stem cells form the tissue in which they reside. Hence, it is thought that bone marrow stem cells under the influence of the new microenvironment after transplantation start to adopt the new phenotype and produce cells of the resident tissue (39, 52). However, these findings have been challenged by several research groups that have independently advocated the possibility of fusion between donor bone marrow cells with host cells to adopt the phenotype of the host tissue (134, 153). Recent publications from Alvarez and colleagues (5) have shown fusion between donor bone marrow cells and Purkinje fibers, cardiomyocytes, and hepatocytes. Thus there is a prevailing notion that fusion between donor stem cells and host tissue cells might be misleading the researchers to conclude that stem cells can cross the boundaries of lineage restriction. Back-to-back recent reports from Balsam et al. (11) and Murry et al. (91) have clearly depicted a lack of ability of donor bone marrow cells to undergo differentiation into cardiomyocytes after transplantation. They have shown little evidence for transplanted bone marrow cells to form cardiomyocytes at the site of the graft posttransplantation. Similar concern has been shown by earlier researchers when isolated unfractionated bone marrow cells were found to be unable to differentiate into cardiomyocytes (13). These results are presenting a serious challenge to the findings that have been documented by Orlic and colleagues (101) and thus require an in-depth assessment of whether bone marrow stem cells have the required plasticity to transdifferentiate into cardiomyocytes posttransplantation. CARDIOMYOGENIC TRANSDIFFERENTIATION OF BONE MARROW STEM CELLS IN VITRO Cardiomyogenic differentiation of stem cells has been vastly reported (60, 102, 138). The cells undergoing cardiomyogenic Table 1. In vitro studies on BMC transdifferentiation into cardiovascular-related lineages References Cells Makino et al. (77) Fukuda et al. (32) Fuchs et al. (30) Toma et al. (137) Terada et al. (134) Eisenberg et al. (27) Fukuhara et al. (33) Oswald et al. (103) BMSC BMSC BMC hBMMSC BMMNC HPC BMSC hBMMSC Coculture Pretreatment No ESC Chick embryo heart tissue Cardiomyocytes 5-Aza 5-Aza Yes MyoD transduction IL-3 for 7 days RA and ECGS PGE2 and IL-2 VEGF Differentiation Myocytes Myocytes Myocytes Myocytes Myocytes Myocytes Endothelial cells BMC, bone marrow cells; BMSC, bone marrow stromal cells; 5-Aza, 5-azacytidine; hBMMSC, human bone marrow mesenchymal stem cells; BMMNC, bone marrow mononuclear cells; ESC, embryonic stem cells; IL, interleukin; HPC, hemapoietic progenitor cells; RA retinoic acid; ECGS, endothelial cell growth supplement. AJP-Heart Circ Physiol • VOL 288 • JUNE 2005 • www.ajpheart.org Downloaded from http://ajpheart.physiology.org/ by 10.220.32.247 on April 29, 2017 infracted myocardium (92), and tissue injury is considered as one important factor that influences the transdifferentiation of bone marrow cells to other lineages (1). BMMNCs taken from myocardial infarction patients have been found to show tropism for damaged cardiac tissue (10a). Similarly, there is a significant debate over the presence of stem cells from extracardiac origin in the myocardium (12, 110). Despite these interesting findings, the underlying mechanism as to how the donor bone marrow stem cells home into the damaged myocardium and contribute toward improved cardiac function remains highly debatable (97, 118). However, it is considered to be the resultant effect of more than one mechanism. First, bone marrow cells undergo differentiation into cardiomyocytes, either due to preprogramming or under the influence of signals from myocardial microenvironment (64, 100, 121, 140). Second, they contribute toward improved wall thickness and a reduction in the infarct size. Bone marrow stem cells have been shown to express angiogenic growth factors in a paracrine way to stimulate neovascularization at the site of the cell graft and undergo transdifferentiation into endothelial cells to participate in angiogenesis, thus alleviating myocardial ischemia (42, 132, 139). The paracrine effect may not be the effect of individual cytokines themselves. Rather, this may be related with their synergistic interaction that may lead to the beneficial outcome in terms of neovascularization. Kinnaird and colleagues (62) have reported a full spectrum of arteriogenic cytokines released from bone marrow stromal cells. The expression of these growth factors gets accentuated under stressful hypoxic conditions (8). Mesenchymal stem cells grown under hypoxic conditions migrated and formed three-dimensional capillarylike structures on a Matrigel matrix. They also showed these effects when triggered by conditioned media taken from mesenchymal stem cells grown under hypoxic stress. These observations clearly depict the involvement of both paracrine as well as autocrine mechanisms. The role of paracrine signaling pathways as a mediator of bone marrow cell therapy has also been highlighted in vivo in the treatment of tissue ischemia, which clearly depicts that donor cell incorporation into vessels is not a prerequisite for their effects in angiogenesis (63). An interesting study from Pak et al. (104) showed that bone marrow cell transplantation induces cardiac nerve sprouting and sympathetic hyperinnervation. Another proposed mechanism is the fusion of donor bone marrow cells with host cardiomyocytes to adopt their phenotype (123). The donor cell genes may supplement for the lost genetic material from the host nucleus during the ischemic injury. Out of all these Invited Review H2559 BONE MARROW STEM CELLS FOR HEART Table 2. Small animal model studies used for BMC transplantation for cardiac repair Model Rat Tomita et al. (138) Wang et al. (143) Wang et al. (144) Davani et al. (24) Cells Pretreatment Angiogenesis BMC BMSC BMSC BMMPC 5-Aza No No No CAL CAL CAL Doxorubicin CAL CAL BM-MSC BMSC BMC ⫹ myoblasts BMMNC BMMSC BMMNC HGF transduction 5-Aza No No No No CAL CAL Lin⫺ ckit⫹ SP No Yes Yes Saito et al. (114) CAL BMSC No Yes Toma et al. (137) Agbulut et al. (3) Kudo et al. (68) Hiasa et al. (47) Murry et al. (91) Balsam et al. (11) Normal Doxorubicin CAL CAL Normal/CAL CAL hBMMSC BMC Lin⫺ ckit⫹ BMMNC Lin⫺ ckit⫹ Lin⫺ ckit⫹ and Lin⫺ ckit⫹ Thy1.1loSca⫹ No No No No No No Yes No No No Duan et al. (26) Saito et al. (115) Sakaghuchi et al. (116) Ishida et al. (54) Tang et al. (132) Zhang et al. (156) Mouse Orlic et al. (102) Jackson et al. (55) Yes Yes Yes Yes Yes Yes Yes Myocytes Myocytes Myocytes Smooth muscle and endothelial phenotype Myocyte-like cells Myocytes Endothelial cells Endothelial cells Myocytes Myocytes and endothelial cells Vascular smooth muscle cells and myocytes Myocytes Myocytes Myocytes No No No CAL, coronary artery ligation; HGF, hepatocyte growth factor; SP, side population. plemented with retinoic acid, DMSO, and 5-azacytidine (5-Aza) (45). Cardiomyogenic differentiation of bone marrow in vitro has specifically been achieved using the demethylating agent 5-Aza (Table 1). Makino et al. (77) reported 5-Aza-induced differentiation of mice bone marrow stromal cells into cardiac-like cells. At a concentration of 3 mol/l for 1 wk, 5-Aza induced bone marrow cells into cardiomyogenic cells. These cells stained positive for myosin, actin, and desmin and showed spontaneous beating at 3 wk after treatment. Electron microscopy revealed a cardiomyocyte-like ultrastructure, such as the presence of sarcomeres, centrally positioned nuclei, and atrial granules. Coculture of bone marrow stem cells with cardiomyocytes has been shown to preprogram these cells to adopt a cardiac phenotype. Our research group (147) has recently shown that differentiation achieve the cardiomyocyte phenotype through the expression of specific genes encoding various transcription factors and structural and regulatory proteins (105). Among these are included GATA-4, Nkx 2.5, MEF2, and HAND. However, the exact role of these genes, the timing of their activation, and the signaling pathways involved in mediating cardiomyogenic differentiation remain unknown. Besides these, a recent report (41) has shown that they also express functional adrenergic and muscrinic receptors that modulate their function. Various strategies have been adopted for directed differentiation of stem cells into cardiomyocytes (45). The induction of cardiomyogenic differentiation of stem cells has been achieved by culturing bone marrow cells in vitro using culture medium supTable 3. Large animal studies using BMC for cardiac repair Pig Kamihata et al. (56) Fuchs et al. (30) Shake et al. (121) Tomita et al. (139) Min et al. (84) Pak et al. (104) Yau et al. (150) Dog Hamano et al. (42) Sheep Bel et al. (13) Airey et al. (4) Model Cells Pretreatment Angiogenesis LAD ligation Ameroid ring 60-min LAD occlusion LAD occlusion LAD branch ligation LAD microcoil embolization Coil occlusion Differentiation BMMNC BMC BMMSC BMSC hMSC⫹ hFC BMMSC No No No 5-Aza No No Yes Yes Yes Yes Yes Yes Yes Yes Nerve sprouting BMSC No Yes Yes LAD ligation Fresh BMC No Yes Yes LCx ligation In utero injection Fresh BMC hMSC No No Yes No Pukinje fibers LAD, left anterior descending coronary artery; hMSC, human mesenchymal stem cells; hFC, human fetal cardiomyocytes; LCx, left circumflex coronary artery. AJP-Heart Circ Physiol • VOL 288 • JUNE 2005 • www.ajpheart.org Downloaded from http://ajpheart.physiology.org/ by 10.220.32.247 on April 29, 2017 Cryoinjury Normal heart CAL CAL Differentiation Invited Review H2560 BONE MARROW STEM CELLS FOR HEART cell-to-cell contact during coculture of bone marrow cells with cardiomyocytes is imperative to trigger their cardiomyogenic transformation. TRANSDIFFERENTIATION OF BONE MARROW STEM CELLS IN VIVO AJP-Heart Circ Physiol • VOL CLINICAL STUDIES Since the first human autologous skeletal myoblasts transplantation (82), more research groups have been involved in phase 1 safety and feasibility studies using adult stem cell transplantation for cardiac repair, including bone marrow cells. The underlying principle is to take advantage of the plastic nature of bone marrow stem cells, which enables them to cross the lineage restriction and participate in the reparative process by attaining the cardiac phenotype. Whereas some of these studies have been carried out as the sole-therapy procedure using a bone marrow cell implantation approach (10a, 14, 31, 106, 141), others have been performed as an adjunct to either coronary artery bypass grafting (34, 109, 126, 127, 154) or percutaneous revascularization (10, 19, 22, 125, 129, 145). The small number of the patients in each study (without a blinded control group) and their performance as an adjunct procedure make it difficult to assess and attribute the 288 • JUNE 2005 • www.ajpheart.org Downloaded from http://ajpheart.physiology.org/ by 10.220.32.247 on April 29, 2017 Encouraged by the results from in vitro studies, both small and large animal studies have been carried out to show that the whole bone marrow and its subpopulations potentially repopulate the injured myocardium and undergo milieu-dependent differentiation to form endothelial cells and cells with a cardiomyocyte-like phenotype (Tables 2 and 3). It has been hypothesized that preprogramming donor bone marrow cells to adopt a cardiomyogenic differentiation pathway before their transplantation in animal models may have better chances of their transdifferentiation into cardiomyocytes than transplantation of uncommitted bone marrow cells (16, 138). The heart function of the 5-Aza-treated bone marrow cell transplanted group was better than that of other groups. Liechty et al. (74) demonstrated in vivo site-specific differentiation of human bone marrow into cardiomyocytes. The cells were directly injected into the fetal sheep peritoneal cavity. Lin⫺ ckit⫹ bone marrow cells developed into fetal and neonatal myocytes in infarcted mice hearts (101). They were positive for cardiac myosin, GATA-4, MEF2, and Csx/Nkx 2.5. The cells were also positive for connexin43, indicating intercellular communication between the grafted cells and host tissue. A highly enriched hematopoietic CD34⫺ “side population” of bone marrow cells was transplanted into lethally irradiated C57BL/ 6-Ly-5.1 mice (55). The engrafted side population bone marrow cells differentiated into cardiomyocytes and endothelial cells. The derived cardiomyocytes were found primarily in the peri-infarct region. These studies suggested that signals originating from the cytokine-rich microenvironment of the injured myocardium and the direct cell-cell interaction between donor bone marrow cells and host cardiomyocytes triggered their myogenic differentiation. The injured heart is a more efficient inducer of bone marrow cells differentiation into cardiomyocytes (64). Shintani et al. (124) demonstrated that endothelial progenitor cells were mobilized into the peripheral blood and contributed to neovascularization in the heart during an acute infarction event in humans. These studies suggested that inflammatory cytokines and factors released by the infarcted heart into the peripheral blood may have the potential to trigger circulating bone marrow cells to differentiate into specific cell lineages. Condorelli et al. (23) observed that the majority of endothelial cells injected into infarcted mice differentiated into myosin-positive cells with a cardiomyocytes-like morphology, whereas only a very few of them differentiated into cardiomyocytes after injection into the normal mice heart. Our research group (68) has previously shown that transplantation of bone marrow-derived Lin⫺ ckit⫹ cells significantly reduced infarction and fibrosis in an ischemic mouse heart. The donor bone marrow cells differentiated into cardiomyocytes and endothelial cells in the ischemically damaged murine heart. Transplantation of bone marrow stromal cells has also been shown to improve the functioning of the healed infarcted rat heart through myogenesis and angiogenesis (99). The angiogenic potential of bone marrow cells posttransplantation may be enhanced by subjecting the cells to ischemic stress before transplantation (75). In recent study (117), granulocyte colonystimulating factor (G-CSF)-mobilized human bone marrow CD34⫹ and CD34⫺ cells were delivered intravenously into an infracted nude rat heart model of myocardial infarction. The cells were found to migrate and repopulate the ischemic myocardium and induce neovascularization. There was a resultantly improved cardiac function and reduced remodeling. To achieve controlled delivery of the transplanted bone marrow cells, Liu et al. (75) used a novel fibrin patch-based delivery of cells. A fibrin patch coated with autologous bone marrow cells was placed on the infarct site. The results revealed that the transplanted cells differentiated into cardiomyocyte-like cells and participated in the angiogenic process and became part of the capillary network. Taken together, these data suggest that the injured heart might have a greater contribution to the milieu-dependent cardiomyocyte differentiation of bone marrow cells. However, the information on the signaling molecules and responding molecular mechanisms that recruit bone marrow cells to the injured heart and transdifferentiation into cardiomyocytes is still unclear. Myocardial infarction can mobilize bone marrow cells and recruit them to injured myocardium where they get stimulated for transformation into new cardiomyocytes. One important consideration, however, is that the plastic and malleable nature of unselected multipotent bone marrow may be disadvantageous and results in unwarranted and unwanted outcomes. The presence of cells with osteogenic potential or a multipotent stem cell population together with local milieu of the cytokine-rich infarcted myocardium may favor osteogenic differentiation of bone marrow cells and enhance calcium deposition with an as-yet-undefined regulatory mechanism. It has been shown that transplantation of unselected bone marrow cells into the acutely infarcted myocardium may cause significant intramyocardial calcification, thus leading to contractile dysfunction or arrhythmias (155). The calcification in the bone marrow cell-transplanted hearts was identified in the periinfarct area or normal myocardium, where the myocardial structure was relatively well preserved. Similarly, transplantation of undifferentiated mesenchymal stem cells has been shown to develop into fibroblastic scar tissue (144). These results underscore the importance of regulating cellular differentiation of adult stem cells in therapeutic applications. Invited Review H2561 BONE MARROW STEM CELLS FOR HEART Table 4. Randomized clinical studies with control groups using BMC Patients Study Control With cells Cell type Assumus (10) 09 20 BMMNC Chen (22) 35 34 BMMNC Wollert (145) 30 30 CD34⫹ Composition 7.35 ⫾ 7.31 ⫻ 106 CD34/CD45-positive cells Delivery Mode Adjunct Procedure IC/CPC PCI IC PCI IC PCI 24.6 ⫾ 9.4 ⫻ 108 nucleated cells, 9.5 ⫾ 6.3 ⫻ 106 CD34⫹ cells, and 3.6 ⫾ 3.4 ⫻ 106 hemopoietic colony-forming cells Result Summary Improved regional wall motion in the infarct area, enhanced LVEF, profoundly reduced LVESV, enhanced viability in the infarcted one by DS-echocardiography, and quantitative PET scan Improved wall velocity in the infracted segments, reduction in perfusion defects, improved LVEF, and significantly reduced LVESV by echocardiography, NOGA EMM, and PET scanning Improved LVEF 24-h Holter monitoring and functional MRI IC, intracoronary; CPC, circulating progenitor cells; PCI, percutaneous coronary intervention; LVEF, left ventricular ejection fraction; LVESV, left ventricular end-systolic volume; DS, dobutamine stress; PET, positron emission tomography; NOGA, EMM, electromechanical mapping system. AJP-Heart Circ Physiol • VOL 288 • JUNE 2005 • www.ajpheart.org Downloaded from http://ajpheart.physiology.org/ by 10.220.32.247 on April 29, 2017 sure (129). The control group patients received 6 ml of normal saline solution without cells using the same method. The patients underwent [18F]fluorodeoxyglucose PET scanning and echocardiography on the day of cell transplantation and were followed up at 3 and 6 mo. The follow-up results were encouraging and showed significant differences between the two groups of patients. The percentage of hypokinetic, akinetic, and dyskinetic areas in the left myocardium significantly decreased (from 32 ⫾ 5% to 13 ⫾ 11%), whereas wall motion velocity (from 2.17 ⫾ 1.3 to 4.2 ⫾ 2.5 cm/s) and left ventricular ejection fraction (LVEF; from 49 ⫾ 9% to 67 ⫾ 11%) registered significant increases in the cell transplanted patients together with significantly decreased perfusion defects as detected by PET. The most encouraging finding of the study was that the indicators of improvement in cardiac performance were maintained unruffled until 6 mo of observation. The Bone Marrow Transfer to Enhance S-T Elevation Infarct Regeneration study, a recent randomized controlled clinical trial involving 60 patients, was reported by Wollert and colleagues (145). The patients were randomized to receive optimum medical treatment and PCI together with autologous bone marrow cell transplantation (n ⫽ 30) or without cell transplantation as the control group (n ⫽ 30). A total of 24.6 ⫻ 108 freshly isolated CD34⫹ cells were transplanted by intracoronary infusion using a balloon catheter in the infarct related artery. Mean global LVEF showed a 7% increase in the stem cell transfer group compared with 0.7% in the medical therapy group (P ⫽ 0.0026). Study limitations included a lack of sham-operated control subjects and an inability to determine the mechanisms of action of bone marrow cells. Zeiher’s group, in Germany, has documented preliminary results of the Transfer of Progenitor Cells and Regeneration Enhancement in Acute Myocardial Infarction study. The randomized study, which previously reported 20 patients, included 8 more patients to the cohort (10, 19). Interestingly, the study involves a comparison between BMMNC and circulating progenitor cells (CPC) in blood for cardiac repair together with an internal reference group of 11 patients who were included as a real benefit and improvement in cardiac function to bone marrow cell transplantation. Invariably, all the studies have used autologous bone marrow cell transplantation. However, they differ in the processing, culture, and selection of the subpopulation before transplantation. For example, unlike Galinanes et al. (34), who used unmanipulated autologous bone marrow (34), and Tse et al. (141), who used unselected BMMNC for transplantation, others have tried to purify a subpopulation of BMMNC (106, 126, 129, 145). NOGA has been used for electromechanical mapping to discriminate between the ischemic and viable regions and for targeted delivery of cells (106, 141). The methods for the end-point measurement have been variable and include treadmill exercise duration, consumption of nitroglycerine, single photon emission computed tomography (SPECT) perfusion imaging, electromechanical mapping system (NOGA, EMM), echocardiography, [18F]fluorodeoxyglucose positron emission tomography (PET), and magnetic resonance imaging. In most cases, the cell transplantation procedure was uneventful, and the patients recovered well without any postprocedural complications. No arrhythmic changes have been reported on Holter monitoring during any study. Only two deaths, one each in the experimental and control groups, were reported by Perin et al. (106). However, both these deaths were unrelated to the cell transplantation procedure. Despite their observational status and design limitations, their outcome reveals the safety and feasibility of the approach. Taken together, the results of the phase 1 studies have been encouraging. Table 4 summarizes the bone marrow cell transplantation reports with the largest number of patients published in refereed journals. The largest study, with 78 patients, was reported by Chen et al. (22). The patients were randomized to receive bone marrow cells (n ⫽ 34) and only percutaneous coronary intervention (n ⫽ 35) as the control group. After being cultured for 10 days in vitro, 8 –10 ⫻ 109 cells/ml of autologous bone marrow cells were resuspended in 6 ml of heparinized saline solution and transfused into the infarct related target coronary artery through an inflated over-the-balloon catheter with high pres- Invited Review H2562 BONE MARROW STEM CELLS FOR HEART BONE MARROW STEM CELL MOBILIZATION BMMNC taken from myocardial infarction patients have been found to show tropism for damaged cardiac tissue in vitro (28). Moreover, there is evidence that repair of cardiac and vascular tissue by bone marrow stem cells are naturally occurring processes after injury (35, 124). Besides tissue-specific resident stem cells, a very low level of progenitor cells move from their bone marrow niche into peripheral blood under physiological conditions as a part of the homeostatic mechanism. However, in patients with acute myocardial infarction, circulating mononuclear cells are significantly increased (124). It is thought that tissue ischemia mobilizes mononuclear cells from the bone marrow to the peripheral blood, and the mobilized mononuclear cells home specifically to participate in neovascularization and differentiate into mature endothelial cells (130). It has been demonstrated that after myocardial infarction, mesenchymal stem cells are recruited to the injured heart, where they undergo milieu-dependent differentiation and may participate in the pathophysiological mechanisms of postinfarct remodeling, angiogenesis, and maturation of the scar (17). However, the process is far from being adequate to compensate for the massive loss of cardiomyocytes and needs to be supported for its inadequacy from an outside intervention. Attempts are being made to pharmacologically augment the process of mobilization of progenitor cells from the bone marrow niche for their homing into the infarcted myocardium (96). Stem cell mobilization using various cytokines and growth factors is routinely practiced in hematological procedures. The use of cytokines for induction of endogenous bone marrow stem cells to home into the infarcted myocardium is gaining popularity. It is less invasive and obviates the use of cells from nonautologous sources and hence the risk of transmission of infectious agents and immunological rejection of the cell graft. These advantages of cytokine-induced mobilization of endogenous bone marrow stem cells make it a superior choice for regenerating infarcted myocardium. Various cytokines and growth factors either alone or in combination together can release HSC from the bone marrow into the peripheral blood (7, 85, 90, 100, 119, 149). G-CSF is currently the most commonly used agent for HSC mobilization (131). This is AJP-Heart Circ Physiol • VOL based on the fact that G-CSF is an effective chemoattractant for bone marrow stem cells and enhances the infiltration of the side population after myocardial infarction in mice (2). The outcome of the mobilization protocol is significantly influenced by the dose and route of G-CSF administration. Similarly, a comparative study (113) between continuous administration and bolus administration of G-CSF has shown that the former mode of administration reduced activation of polymorphonuclear cells. Treatment with G-CSF also induces an angiogenic response (120). Despite its effectiveness in translocation of bone marrow cells from their niche, the high dose of G-CSF that is required to achieve bone marrow cell mobilization is not without side effects (49, 58, 79). To overcome this problem, a combination of G-CSF with stem cell factor-1 (SCF-1) has been used (146). SCF is expressed constitutively in bone marrow stromal cells, fibroblasts, and endothelial cells and is essential to the survival, proliferation, adhesion/migration, and differentiation of HSC (20, 43). The synergistic interaction between G-CSF and other cytokines in mobilizing progenitor cells from the bone marrow has been demonstrated by multiple studies in animals and humans (38, 70, 89). Recent studies support the ability of HSC induced by cytokine(s) to transdifferentiate into cardiomyocytes; however, nothing is actually known regarding the process of transendothelial migration of HSC to the myocardium. In the hematopoietic microenvironment, bone marrow-derived endothelial cells may play an important role in the trafficking and maintenance of progenitor and stem cells due to adhesive interactions and paracrine secretion of hematopoietic growth factors. It is hypothesized that bone marrow cells are integrated in their bone marrow niche with the bone marrow stroma. For the translocation of cells from their bone marrow niche under the influence of various cytokines, it is imperative to break these cytoadhesive interactions before they are blood borne (67). Besides others, CXCR-4 is a cell surface antigen expressed on hematopoietic progenitor cells including the primitive, pluripotent CD34⫹ subpopulation and is related to efficient SDF1-induced migration in vitro (88, 107). Stromal cell derived factor-1 (SDF-1), through its receptor CXCR-4, is believed to be superior in stem cell mobilization, angiogenesis, and cell survival. Besides, G-CSF-induced HSC mobilization may also involve the SDF-1/CXCR-4 axis (107). Homing in of the mobilized stem cells to the injured myocardium is milieu dependent. Ischemia enhances the homing-in process. A multitude of local and systemic factors influence the homing-in of stem cells, including VEGF and its receptor-2, c-kit, and stem cell factors (93). FUTURE DIRECTIONS Stem cell therapy in general (44, 50, 51) and therapy based on bone marrow-derived stem cells in particular (31, 105, 127) is quickly emerging as an alternative strategy in cardiovascular therapeutics. Proof-of-concept animal studies and phase 1 clinical trials have already shown the safety and feasibility of this approach. However, there are some fundamental issues that need to be resolved to streamline research in this area. The ability of bone marrow cells to transdifferentiate into cardiomyocytes and integrate into the host tissue is being questioned. The proponents of fusion as the mechanism for the survival of donor cells posttransplantation are arguing for the development 288 • JUNE 2005 • www.ajpheart.org Downloaded from http://ajpheart.physiology.org/ by 10.220.32.247 on April 29, 2017 control for comparison of results. BMMNC (CD34⫹/CD45⫹) were purified from autologous bone marrow aspirates of each patient undergoing BMMNC transplantation, and CPC were purified and expanded ex vivo for 3 days for each patient undergoing CPC transplantation from 250 ml venous blood. Except for one patient who suffered anterior wall infarction 3 days after cell transplantation, the whole exercise was without any problem. A 4 mo follow-up revealed improvement in global cardiac function; however, it did not differ between patients receiving BMMNC or CPC. The control group patients without cell therapy revealed no significant changes in the respective parameters of observation. The study results highlight the safety and efficacy of the procedure, like many of the previously reported studies. Moreover, it also showed that transplantation of CPC, the collection and availability of which is relatively easy and less invasive compared with BMMNC, is as effective as BMMNC in improving contractile function of the heart and coronary artery flow reserve. Invited Review BONE MARROW STEM CELLS FOR HEART AJP-Heart Circ Physiol • VOL provide an alternative option with superior attributes in cell therapy for cardiac repair. The results of the phase 1 clinical studies have been encouraging. However, in the absence of a blinded control group, and with a small number of patients involved in most of these studies, it is difficult to assert the beneficial effects of stem cell therapy. Furthermore, it is important to define the patient population that can benefit from cell therapy. For this purpose, a more concerted effort between the various research groups involved is needed. REFERENCES 1. Abedi M, Greer DA, Colvin GA, Demers DA, Dooner MS, Harpel JA, Pimentel J, Menon MK, and Quesenberry PJ. Tissue injury in marrow transdifferentiation. Blood Cells Mol Dis 32: 42– 46, 2004. 2. Adachi Y, Imagawa J, Suzuki Y, Yogo K, Fukazawa M, Kuromaru O, and Saito Y. G-CSF treatment increases side population cell infiltration after myocardial infarction in mice. J Mol Cell Cardiol 36: 707–710, 2004. 3. Agbulut O, Menot ML, Li Z, Marotte F, Paulin D, Hagege AA, Chomienne C, Samuel JL, and Menasche P. Temporal patterns of bone marrow cell differentiation following transplantation in doxorubicin induced cardiomyopathy. Cardiovasc Res 58: 451– 459, 2003. 4. Airey JA, Almeida-Porada G, Colletti EJ, Porada CD, Chamberlain J, Movsesian M, Sutko JL, and Zanjani ED. Human mesenchymal stem cells form Purkinje fibers in fetal sheep heart. Circulation 109: 1401–1407, 2004. 5. Alvarez-Donaldo M, Pardal R, Garcia-Verdugo JM, Fike JR, Lee HO, Pfeiffer K, Lois C, Morrison SJ, and Alvarez-Buylla A. Fusion of bone-marrow-derived cells with Purkinje neurons, cardiomyocytes and hepatocytes. Nature 425: 968 –973, 2003. 6. Anderson DJ, Gage FH, and Weissman IL. Can stem cell cross lineage boundaries? Nat Med 7: 393–395, 2001. 7. Andrews RG, Bensinger WI, Knitter GH, Bartelmez SH, Longin K, Bernstein ID, Appelbaum FR, and Zsebo KM. The ligand for c-kit, stem cell factor, stimulates the circulation of cells that engraft lethally irradiated baboons. Blood 80: 2715–2720, 1992. 8. Annabi B, Lee YT, Turcotte S, Naud E, Desrosiers RR, Champagne M, Eliopoulos N, Galipeau J, and Beliveau R. Hypoxia promotes murine bone-marrow-derived stromal cell migration and tube formation. Stem Cells 21: 337–347, 2003. 9. Asahara T, Masuda H, Takahashi T, Kalka C, Pastore C, Silver M, Kearne M, Magner M, and Isner JM. Bone marrow origin of endothelial progenitor cells responsible for postnatal vasculogenesis in physiological and pathological neovascularization. Circ Res 85: 221–228, 1999. 10. Assmus B, Schachinger V, Teupe C, Britten M, Lehmann R, Dobert N, Grunwald F, Aicher A, Urbich C, Martin H, Hoelzer D, Dimmeler S, and Zeiher AM. Transplantation of progenitor cells and regeneration enhancement in acute myocardial infarction (TOPCARE-AMI). Circulation 106: 3009 –3017, 2002. 10a.Aviles FF, San Roman JA, Garcia Frade J, Valdes M, Sanchez A, de la Fuente L, Penarrubia MJ, Fernandez ME, Tejedor P, Duran JM, Hernandez C, Sanz R, and Garcia Sancho J. [Intracoronary stem cell transplantation in acute myocardial infarction]. Rev Esp Cardiol 57: 201–208, 2004. 11. Balsam LB, Wagers AJ, Christensen JL, Kofidis T, Weissman IL, and Robbins RC. Haematopoietic stem cells adopt mature haematopoietic fates in ischemic myocardium. Nature 428: 668 – 673, 2004. 12. Bayes-Genis A, Muniz-Diaz EM, Catasus L, Arilla M, Rodriguez C, Sierra J, Madoz PJ, and Cinca J. Cardiac chimerism in recipients of peripheral-blood and bone marrow stem cells. Eur J Heart Fail 6: 399 – 402, 2004. 13. Bel A, Messas E, Agbulut O, Richard P, Samuel JL, Bruneval P, Hagege AA, and Menasche P. Transplantation of autologous fresh bone marrow into infarcted myocardium: a word of caution. Circulation 108: 247–252, 2003. 14. Beran G, Glogar D, and Lang IM. Improved myocardial viability following intramyocardial autologous bone marrow injection after acute myocardial infarction (Abstract). Heart 89: 930, 2003. 288 • JUNE 2005 • www.ajpheart.org Downloaded from http://ajpheart.physiology.org/ by 10.220.32.247 on April 29, 2017 of hybrid cells as a result of fusion between donor cells and host cardiomyocytes, thus exhibiting a dual phenotype. Subsequently, the hybrid cells take on the function of the existing cells and proliferation results from the hybrid cells rather than stem cell transdifferentiation. However, they have failed to explain the extensive tissue regeneration that so many earlier studies have shown to occur after cell transplantation. These issues regarding the mechanistic basis of cell transplantation need extensive and in-depth studies. Resolving this issue is imperative because fused cells may have a different therapeutic potential and prognostic outcome compared with differentiated cells. Combining bone marrow stem cell transplantation together with the delivery of therapeutic genes to the injured myocardium is an attractive alternative strategy. A previous study (40) has shown the effectiveness of overexpression of angiogenic genes together with stem cell transplantation in animal models. Genetic modulation of bone marrow stromal cells to overexpress the endothelial nitric oxide synthase gene did not interfere with their differentiation potential (25). Transplantation of mesenchymal stem cells overexpressing Akt has been shown to improve the survival of the donor cell and prevent ventricular remodeling together with improved cardiac function (78). Age-related poor proliferative and differentiation potential of bone marrow stem cells is an important parameter that needs special consideration. Hence, in the case of old patients, the pros and cons of using autologous bone marrow cells for transplantation need to be carefully weighed. It has been shown that bone marrow undergoes age-related changes with respect to proliferative capacity and multilineage potential (87, 128). A clear relevance has been established between an intrinsic asyet-undefined genetically controlled program of impaired stem cell functioning with aging. Interestingly, the stem cell pool in short-lived DBA/2 (D2) mice was reduced during aging, in contrast to long-lived C57BL/6 (B6) mice (57). Besides, growth of bone marrow stromal cells is better from bone marrow aspirates of younger patients (122). In the light of these observations, the age of the donor of bone marrow stem cells for transplantation has a strong influence on the outcome of the procedure. Mobilization of bone marrow cells for cardiac repair is an interesting approach. Use of G-CSF has shown promise but has untoward effects that may limit its clinical application (49, 136). The combination of G-CSF with other cytokines and growth factors has been used for mobilization effects and to overcome this problem (93, 142). Studies have also shown that stem cells show a uniquely selective response to various cytokines and combinations of cytokines (146). The knowledge about a specific subpopulation of bone marrow cells that can differentiate into cardiomyocytes combined with the novel concept of lineage-specific mobilization may help to achieve better results with fewer side effects of the cytokine therapy. Like numerous other tissues that house their resident stem cells, there is strong evidence for the presence of a myocardial stem cell-like population that retains the characteristics of other stem cells. However, with a decreased ability to change their genotype and gene expression profile, they are considered to have myocardium-restricted functions (48, 83). Hence, besides transplantation and mobilization strategies, activation of the resident stem cells for participation in the repair process may H2563 Invited Review H2564 BONE MARROW STEM CELLS FOR HEART AJP-Heart Circ Physiol • VOL 35. 36. 37. 38. 39. 40. 41. 42. 43. 44. 45. 46. 47. 48. 49. 50. 51. 52. 53. 54. 55. cardium is safe and enhances cardiac function in humans. Cell Transplant 13: 7–13, 2004. Gill M, Dias S, Hattori K, Rivera ML, Hicklin D, Witte L, Girardi L, Yurt R, Himel H, and Rafii S. Vascular trauma induces rapid but transient mobilization of VEGF2(⫹) AC133(⫹) endothelial precursor cells. Circ Res 88: 167–174, 2001. Goodell MA, Rosenzweig M, Kim H, Marks DF, DeMaria M, Paradis G, Grupp SA, Sieff CA, Mulligan RC, and Johnson RP. Dye efflux studies suggest that hematopoietic stem cells expressing low or undetectable levels of CD34 antigen exist in multiple species. Nat Med 3: 1337–1345, 1997. Graf T. Differentiation plasticity of hematopoietic cells. Blood 99: 3089 –3101, 2002. Grafte-Faure S, Levesque C, Ketata E, Jean P, Vasse SC, and Vannier JM. Recruitment of primitive peripheral blood cells: synergism of interleukin 12 with interleukin 6 and stromal cell-derived factor-1. Cytokine 12: 1–7, 2000. Grove JE, Bruscia E, and Krause D. Plasticity of bone marrow derived stem cells. Stem Cells 22: 487–500, 2004. Haider Kh H, Lei Y, Shujia J, Ge R, Law PK, Chua T, Wong P, and Sim EKW. Angiomyogenesis for cardiac repair using human myoblasts as carriers of human vascular endothelial growth factor. J Mol Med 82: 539 –549, 2004. Hakuno D, Fukuda K, Makino S, Konishi F, Tomita Y, Manabe T, Suzuki Y, Umezawa A, and Ogawa S. Bone marrow-derived regenerated cardiomyocytes (CMG Cells) express functional adrenergic and muscarinic receptors. Circulation 105: 380 –386, 2002. Hamano K, Li TS, Kobayashi T, Hirata K, Yano M, Kohno M, and Matsuzaki M. Therapeutic angiogenesis induced by local autologous bone marrow cell implantation. Ann Thorac Surg 73: 1210 –1215, 2002. Hartman M, Piliponsky AM, Temkin V, and Levi-Schaffer F. Human peripheral blood eosinophils express stem cell factor. Blood 97: 1086 – 1091, 2001. Hattan N, Warltier D, Gu W, Kolz C, Chilian WM, and Weihrauch D. Autologous vascular smooth muscle cell-based myocardial gene therapy to induce coronary collateral growth. Am J Physiol Heart Circ Physiol 287: H488 –H493, 2004. Heng BC, Haider KhH, Sim EK, Cao T, and Ng SC. Strategies for directing the differentiation of stem cells into the cardiomyogenic lineage in vitro. Cardiovasc Res 62: 34 – 42, 2004. Herzog EL, Chai L, and Krause DS. Plasticity of marrow-derived stem cells. Blood 102: 3483–3493, 2003. Hiasa K, Egashira K, Kitamoto S, Ishibashi M, Inoue S, Ni W, Zhao Q, Nagata S, Katoh M, Sata M, and Takeshita A. Bone marrow mononuclear cell therapy limits myocardial infarct size through vascular endothelial growth factor. Basic Res Cardiol 99: 1– 8, 2004. Hierlihy AM, Seale P, Lobe CG, Rudnicki MA, and Megeney LA. The post-natal heart contains a myocardial stem cell population. FEBS Lett 530: 239 –243, 2002. Hill JM, Paul JD, Powell TM, McCoy JP, Dunbar CE, Horne M, Csako G, and Cannon RO. Efficacy and risk of granulocyte colony stimulating factor administration in patients with severe coronary artery disease (Abstract). Circulation 108, Suppl IV: 478, 2003. Hodgson DM, Behfar A, Zingman LV, Kane GC, Perez-Terzic C, Alekseev AE, Pucéat M, and Terzic A. Stable benefit of embryonic stem cell therapy in myocardial infarction. Am J Physiol Heart Circ Physiol 287: H471–H479, 2004. Horackova M, Chen AR, Armour JA, Cattini PA, Livingston R, and Byczko Z. Cell transplantation for treatment of acute myocardial infarction: unique capacity for repair by skeletal muscle satellite cells. Am J Physiol Heart Circ Physiol 287: H1599 –H1608, 2004. Horwitz EM. Stem cell plasticity: the growing potential of cellular therapy. Arch Med Res 34: 600 – 606, 2003. Huttmann A, Li L, and Duhrsen U. Bone marrow derived stem cells and plasticity. Ann Hematol 604: 599 – 604, 2003. Ishida M, Tomita S, Nakatani T, Fukuhara S, Hamamoto M, Nagaya N, Ohtsu Y, Suga M, Yutani C, Yagihara T, Yamada K, and Kitamura S. Bone marrow mononuclear cell transplantation had beneficial effects on doxorubicin-induced cardiomyopathy. J Heart Lung Transplant 23: 436 – 445, 2004. Jackson KA, Majka SM, Wang H, Pocius J, Hartley CJ, Majesky MW, Entman ML, Michael LH, Hirschi KK, and Goodell MA. Regeneration of ischemic cardiac muscle and vascular endothelium by adult stem cells. J Clin Invest 107: 1395–1402, 2001. 288 • JUNE 2005 • www.ajpheart.org Downloaded from http://ajpheart.physiology.org/ by 10.220.32.247 on April 29, 2017 15. Bhatia M, Bonnet D, Murdoch B, Gan OI, and Dick JE. A newly discovered class of human hematopoietic cells with SCID-repopulating activity. Nat Med 4: 1038 –1045, 1998. 16. Bittira B, Kuang JQ, Al-Khaldi A, Shum-Tim D, and Chiu RCJ. In vitro pre-programming of marrow stromal cells for myocardial regeneration. Ann Thorac Surg 74: 1154 –1160, 2002. 17. Bittira B, Shum-Tim D, Al-Khaldi A, and Chiu RCJ. Mobilization and homing of bone marrow stromal cells in myocardial infarction. Eur J Cardiothorac Surg 24: 393–398, 2003. 18. Brazekon TR, Rossi FM, Kesher GI, and Blau HM. From bone marrow to brain: expression of neuronal phenotypes in adult mice. Science 290: 1775–1779, 2000. 19. Britten MB, Abolmaali ND, Assmus B, Lehmann R, Honold J, Schmitt J, Vogl TJ, Martin H, Schachinger V, Dimmeler S, and Zeiher AM. Infarct remodeling after intra coronary progenitor cell treatment in patients with acute myocardial infarction (TOPCARE-AMI): mechanistic insights from serial contrast-enhanced magnetic resonance imaging. Circulation 108: 2212–2218, 2003. 20. Broudy VC. Stem cell factor and hematopoiesis. Blood 90: 1345–1364, 1997. 21. Carter JE and Schuchman EH. Mesenchymal stem cell therapy for neurodegenerative disease (Abstract). Neurobiol Aging 21: 152, 2000. 22. Chen SL, Fang WW, Ye F, Liu YH, Qian J, Shan SJ, Zhang JJ, Chunhua RZ, Liao LM, Lin S, and Sun JP. Effect on left ventricular function of intracoronary transplantation of autologous bone marrow mesenchymal stem cells in patients with acute myocardial infarction. Am J Cardiol 94: 92–95, 2004. 23. Condorelli G, Borello U, De Angelis L, Latronico M, Sirabella D, Coletta M, Galli R, Balconi G, Follenzi A, Frati G, Cusella De Angelis MG, Gioglio L, Amuchastegui S, Adorini L, Naldini L, Vescovi A, Dejana E, and Cossu G. Cardiomyocytes induce endothelial cells to trans-differentiate into cardiac muscle: implications for myocardium regeneration. Proc Natl Acad Sci USA 98: 10733–10738, 2001. 24. Davani S, Marandin A, Mersin N, Royer B, Kantelip B, Herve P, Etievent JP, and Kantelip JP. Mesenchymal progenitor cells differentiate into an endothelial phenotype, enhance vascular density, and improve heart function in a rat cellular cardiomyoplasty model. Circulation 108: 253–258, 2003. 25. Deng W, Bivalacqua TJ, Chattergoon NN, Hyman AL, Jeter JR Jr, and Kadowitz PJ. Adenoviral gene transfer of eNOS: high-level expression in ex vivo expanded marrow stromal cells. Am J Physiol Cell Physiol 285: C1322–C1329, 2003. 26. Duan HF, Wu CT, Wu DL, Lu Y, Liu HJ, Ha XQ, Zhang QW, Wang H, Jia XX, and Wang LS. Treatment of myocardial ischemia with bone marrow-derived mesenchymal stem cells over-expressing hepatocyte growth factor. Mol Ther 8: 467– 474, 2003. 27. Eisenberg LM, Burns L, and Eisenberg CA. Hematopoietic cells from bone marrow have the potential to differentiate into cardiomyocytes in vitro. Anat Rec A Discov Mol Cell Evol Biol 274: 870 – 882, 2003. 28. Fernandez-Aviles F, San Roman JA, Garcia-Frade J, Fernandez ME, Penarrubia MJ, de la Fuente L, Gomez-Bueno M, Cantalapiedra A, Fernandez J, Gutierrez O, Sanchez PL, Hernandez C, Sanz R, Garcia-Sancho J, and Sanchez A. Experimental and clinical regenerative capability of human bone marrow cells after myocardial infarction. Circ Res 95: 742–748, 2004. 30. Fuchs S, Baffour R, Zhou YF, Shou M, Pierre A, Tio FO, Weissman NJ, Leon MB, Epstein SE, and Kornowski R. Transendocardial delivery of autologous bone marrow enhances collateral perfusion and regional function in pigs with chronic experimental myocardial ischemia. J Am Coll Cardiol 37: 1726 –1732, 2001. 31. Fuchs S, Satler LF, Kornowski R, Okubagzi P, Weisz G, Baffour R, Waksman R, Weissman NJ, Cerqueira M, Leon MB, and Epstein SE. Catheter-based autologous bone marrow myocardial injection in no-option patients with advanced coronary artery disease: a feasibility study. J Am Coll Cardiol 41: 1721–1724, 2003. 32. Fukuda K. Development of regenerative cardiomyocytes from mesenchymal stem cells for cardiovascular tissue engineering. Artif Organs 25: 187–193, 2001. 33. Fukuhara S, Tomita S, Yamashiro S, Morisaki T, Yutani C, Kitamura S, and Nakatani T. Direct cell-cell interaction of cardiomyocytes is key for bone marrow stromal cells to go into cardiac lineage in vitro. J Thorac Cardiovasc Surg 125: 1470 –1480, 2003. 34. Galinanes M, Loubani M, Davies J, Chin D, Pasi J, and Bell PR. Auto-transplantation of un-manipulated bone marrow into scarred myo- Invited Review BONE MARROW STEM CELLS FOR HEART AJP-Heart Circ Physiol • VOL 73. 74. 75. 76. 77. 78. 79. 80. 81. 82. 83. 84. 85. 86. 87. 88. 89. 90. 91. angiogenesis induced by bone marrow cell implantation. Am J Physiol Heart Circ Physiol 285: H931–H937, 2003. Li TS, Hayashi M, Liu ZL, Ito H, Mikamo A, Furutani A, Matsuzaki M, and Hamano K. Low angiogenic potency induced by the implantation of ex vivo expanded CD117(⫹) stem cells. Am J Physiol Heart Circ Physiol 286: H1236 –H1241, 2004. Liechty KW, MacKenzie TC, Shaaban AF, Radu A, Moseley AM, Deans R, Marshak DR, and Flake AW. Human mesenchymal stem cells engraft and demonstrate site-specific differentiation after in utero transplantation in sheep. Nat Med 6: 1282–1286, 2000. Liu J, Hu Q, Wang Z, Chengsu Xu C, Wang X, Gong G, Mansoor A, Lee J, Hou M, Zeng L, Zhang JR, Jerosch-Herold M, Guo T, Bache RJ, and Zhang J. Autologous stem cell transplantation for myocardial repair. Am J Physiol Heart Circ Physiol 287: H501–H511, 2004. Lum LG, Fok H, Sievers R, Abedi M, Queensberry PJ, and Lee RJ. Targetting Lin-Sca⫹ heamatopietic stem cells with bispecific antibodies to injured myocardium. Blood Cells Mol Dis 32: 82– 87, 2004. Makino S, Fukuda K, Miyoshi S, Konishi F, Kodama H, Pan J, Sano M, Takahashi T, Hori S, Abe H, Hata J, Umezawa A, and Ogawa S. Cardiomyocytes can be generated from marrow stromal cells in vitro. J Clin Invest 103: 697–705, 1999. Mangi AA, Noiseux N, Kong D, He H, Rezvani M, Ingwall JS, and Dzau VJ. Mesenchymal stem cells modified with Akt prevent remodeling and restore performance of infarcted hearts. Nat Med 9: 1195–1201, 2003. Matsubara H. Risk to the coronary arteries of intracoronary stem cell infusion and GCSF cytokine therapy. Lancet 363: 746 –747, 2004. Matsuura K, Nagai T, Nishigaki N, Oyama T, Nishi J, Wada H, Sano M, Toko H, Akazawa H, Sato T, Nakaya H, Kasanuki H, and Komuro I. Adult cardiac Sca-1-positive cells differentiate into beating cardiomyocytes. J Biol Chem 279: 11384 –11391, 2004. Matsuzaki Y, Kinjo K, Mulligan RC, and Okano H. Unexpectedly efficient homing capacity of purified murine hematopoietic stem cells. Immunity 20: 87–93, 2004. Menasche P, Hagege AA, Scorsin M, Pouzet B, Desnos M, Duboc D, Schwartz K, Vilquin JT, and Marolleau JP. Myoblast transplantation for heart failure. Lancet 357: 279 –280, 2001. Messina E, De Angelis L, Frati G, Morrone S, Chimenti S, Fiordaliso F, Salio M, Battaglia M, Latronico MV, Coletta M, Vivarelli E, Frati L, Cossu G, and Giacomello A. Isolation and expansion of adult cardiac stem cells from human and murine heart. Circ Res 95: 911–921, 2004. Min JY, Sullivan MF, Yang Y, Zhang JP, Converso KL, Morgan JP, and Xiao YF. Significant improvement of heart function by co transplantation of human mesenchymal stem cells and fetal cardiomyocytes in post-infarcted pigs. Ann Thorac Surg 74: 1568 –1575, 2002. Minatoguchi S, Takemura G, Chen XH, Wang N, Uno Y, Koda M, Arai M, Misao Y, Lu C, Suzuki K, Goto K, Komada A, Takahashi T, Kosai K, Fujiwara T, and Fujiwara H. Acceleration of the healing process and myocardial regeneration may be important as a mechanism of improvement of cardiac function and remodeling by postinfarction granulocyte colony-stimulating factor treatment. Circulation 109: 2572– 2580, 2004. Minguell JJ, Erices A, and Conget P. Mesenchymal stem cells. Exp Biol Med 226: 507–520, 2001. Moerman EJ, Teng K, Lipschitz DA, and Lecka-Czernik B. Aging activates adipogenic and suppresses osteogenic programs in mesenchymal marrow stroma/stem cells: the role of PPAR-gamma2 transcription factor and TGF-beta/BMP signaling pathways. Aging Cell 3: 379 –389, 2004. Möhle R, Bautz F, Rafii S, Moore MAS, Brugger W, and Kanz L. The chemokine receptor CXCR-4 is xpressed on CD34⫹ ematopoietic progenitors and leukemic cells and mediates transendothelial migration induced by stromal cell-derived factor-1. Blood 91: 4523– 4530, 1998. Molineux G, McCrea C, Yan XQ, Kerzic P, and McNiece I. Flt-3 ligand synergizes with granulocyte colony-stimulating factor to increase neutrophil numbers and to mobilize peripheral blood stem cells with longterm repopulating potential. Blood 89: 3998 – 4004, 1997. Moore MA, Hattori K, Heissig B, Shieh JH, Dias S, Crystal RG, and Rafii S. Mobilization of endothelial and hematopoietic stem and progenitor cells by adenovector-mediated elevation of serum levels of SDF-1, VEGF, and angiopoietin-1. Ann NY Acad Sci 938: 45– 47, 2001. Murry CE, Soonpaa MH, Reinecke H, Nakajima H, Nakajima HO, Rubart M, Pasumarthi KB, Virag JI, Bartelmez SH, Poppa V, Bradford G, Dowell JD, Williams DA, and Field LJ. Haematopoietic 288 • JUNE 2005 • www.ajpheart.org Downloaded from http://ajpheart.physiology.org/ by 10.220.32.247 on April 29, 2017 56. Kamihata H, Matsubara H, Nishiue T, Fujiyama S, Tsutsumi Y, Ozono R, Masaki H, Mori Y, Iba O, Tateishi E, Kosaki A, Shintani S, Murohara T, Imaizumi T, and Iwasaka T. Implantation of bone marrow mononuclear cells into ischemic myocardium enhances collateral perfusion and regional function via side supply of angioblasts, angiogenic ligands, and cytokines. Circulation 104: 1046 –1052, 2001. 57. Kamminga LM, van Os R, Ausema A, Noach EJ, Weersing E, Dontje B, Vellenga E, and de Haan G. Impaired hematopoietic stem cell functioning after serial transplantation and during normal aging. Stem Cells 23: 82–92, 2005. 58. Kang HJ, Kim HS, Zhang SY, Park KW, Cho HJ, Koo BK, Kim YJ, Soo Lee D, Sohn DW, Han KS, Oh BH, Lee MM, and Park YB. Effects of intracoronary infusion of peripheral blood stem-cells mobilized with granulocyte-colony stimulating factor on left ventricular systolic function and restenosis after coronary stenting in myocardial infarction: the MAGIC cell randomized clinical trial. Lancet 363: 751–756, 2004. 59. Kawada H, Fujita J, Kinjo K, Matsuzaki Y, Tsuma M, Miyatake H, Muguruma Y, Tsuboi K, Itabashi Y, Ikeda Y, Ogawa S, Okano H, Hotta T, Ando K, and Fukuda K. Non-hematopoietic mesenchymal stem cells can be mobilized and differentiate into cardiomyocytes after myocardial infarction. Blood 104: 3581–3587, 2004. 60. Kehat I, Kenyagin-Karsenti D, Snir M, Segev H, Amit M, Gepstein A, Livne E, Binah O, Itskovitz-Eldor J, Gepstein L. Human embryonic stem cells can differentiate into myocytes with structural and functional properties of cardiomyocytes. J Clin Invest 108: 407– 414, 2001. 61. Kim DK, Fujiki Y, Fukushima T, Ema H, Shibuya A, and Nakauchi H. Comparison of hematopoietic activities of human bone marrow and umbilical cord blood CD34 positive and negative cells. Stem Cells 17: 286 –294, 1999. 62. Kinnaird T, Stabile E, Burnett MS, Lee CW, Barr S, Fuchs S, and Epstein SE. Marrow-derived stromal cells express genes encoding a broad spectrum of arteriogenic cytokines and promote in vitro and in vivo arteriogenesis through paracrine mechanisms. Circ Res 94: 678 – 685, 2004. 63. Kinnaird T, Stabile E, Burnett MS, Shou M, Lee CW, Barr S, Fuchs S, and Epstein SE. Local delivery of marrow-derived stromal cells augments collateral perfusion through paracrine mechanisms. Circulation 109: 1543–1549, 2004. 64. Kocher AA, Schuster MD, Szabolcs MJ, Takuma S, Burkhoff D, Wang J, Homma S, Edwards NM, and Itescu S. Neovascularization of ischemic myocardium by human bone-marrow-derived angioblasts prevents cardiomyocyte apoptosis, reduces remodeling and improves cardiac function. Nat Med 7: 430 – 436, 2001. 65. Kondo M, Wagers AJ, Manz MG, Prohaska SS, Scherer DC, Beilhack GF, Shizuru JA, and Weissman IL. Biology of hematopoietic stem cells and progenitors: implications for clinical application. Annu Rev Immunol 21: 759 – 806, 2003. 66. Krause DS, Theise ND, Collector MI, Henegariu O, Hwang S, Gardner R, Neutzel S, and Sharkis SJ. Multi-organ, multi-lineage engraftment by a single bone marrow-derived stem cell. Cell 105: 369 –377, 2001. 67. Kronenwett R, Martin S, and Haas R. The role of cytokines and adhesion molecules for mobilization of peripheral blood stem cells. Stem Cells 18: 320 –330, 2000. 68. Kudo M, Wang Y, Wani MA, Xu M, Ayub A, and Ashraf M. Implantation of bone marrow stem cells reduces the infarction and fibrosis in ischemic mouse heart. J Mol Cell Cardiol 35: 1113–1119, 2003. 69. Lagasse E, Connors H, Al-Dhalimy M, Reitsma M, Dohse M, Osborne L, Wang X, Finegold M, Weissman IL, and Grompe M. Purified hematopoietic stem cells can differentiate into hepatocytes in vivo. Nat Med 6: 1229 –1234, 2000. 70. Lataillade JJ, Clay D, Dupuy C, Rigal S, Jasmin C, Bourin P, and Le Bousse-Kerdiles MC. Chemokine SDF-1 enhances circulating CD34(⫹) cell proliferation in synergy with cytokines: possible role in progenitor survival. Blood 95: 756 –768, 2000. 71. Li TS, Hamano K, Suzuki K, Ito H, Zempo N, and Matsuzaki M. Improved angiogenic potency by implantation of ex vivo hypoxia prestimulated bone marrow cells in rats. Am J Physiol Heart Circ Physiol 283: H468 –H473, 2002. 72. Li TS, Hamano K, Nishida M, Hayashi M, Ito H, Mikamo A, and Matsuzaki M. CD117⫹ stem cells play a key role in therapeutic H2565 Invited Review H2566 92. 93. 94. 95. 96. 98. 99. 100. 101. 102. 103. 104. 105. 106. 107. 108. 109. stem cells do not transdifferentiate into cardiac myocytes in myocardial infarcts. Nature 428: 664 – 668, 2004. Nagaya N, Fujii T, Iwase T, Ohgushi H, Itoh T, Uematsu M, Yamagishi M, Mori H, Kangawa K, and Kitamura S. Intravenous administration of mesenchymal stem cells improves cardiac function in rats with acute myocardial infarction through angiogenesis and myogenesis. Am J Physiol Heart Circ Physiol 287: H2670 –H2676, 2004. Nakamura Y, Tajima F, Ishiga K, Yamazaki H, Oshimura M, Shiota G, and Murawaki Y. Soluble c-kit receptor mobilizes hematopoietic stem cells to peripheral blood in mice. Exp Hematol 32: 390 –396, 2004. Nakauchi H. Hematopoietic stem cells: are they CD34-positive or CD34-negative? Nat Med 4: 1009 –1010, 1998. Nilsson SK, Dooner MS, Weier HU, Frenkel B, Lian JB, Stein GS, and Quesenberry PJ. Cells capable of bone production engraft from whole bone marrow transplants in non-ablated mice. J Exp Med 189: 729 –734, 1999. Norol F, Merlet P, Isnard R, Sebillon P, Bonnet N, Cailliot C, Carrion C, Ribeiro M, Charlotte F, Pradeau P, Mayol JF, Peinnequin A, Drouet M, Safsafi K, Vernant JP, and Herodin F. Influence of mobilized stem cells on myocardial infarct repair in a nonhuman primate model. Blood 102: 4361– 4368, 2003. Nygren JM, Jovinge S, Breitbach M, Sawen P, Roll W, Hescheler J, Taneera J, Fleischmann BK, and Jacobsen SE. Bone marrow-derived hematopoietic cells generate cardiomyocytes at a low frequency through cell fusion, but not transdifferentiation. Nat Med 10: 494 –501, 2004. Oh SH, Muzzonigro TM, Bae SH, LaPlante JM, Hatch H, and Petersen BE. Adult bone marrow-derived cells transdifferentiating into insulin-producing cells for the treatment of type-1 diabetes. Lab Invest 84: 607– 617, 2004. Olivares EL, Ribeiro VP, de Castro JPS, Ribeiro KC, Mattos EC, Goldenberg RCS, Mill JG, Dohmann HF, dos Santos RR, de Carvalho ACC, and Masuda MO. Bone marrow stromal cells improve cardiac performance in healed infarcted rat hearts. Am J Physiol Heart Circ Physiol 287: H464 –H470, 2004. Orlic D, Kajstura J, Chimenti S, Limana F, Jakoniuk I, Quaini F, Nadal-Ginard B, Bodine DM, Leri A, and Anversa P. Mobilized bone marrow cells repair the infarcted heart, improving function and survival. Proc Natl Acad Sci USA 98: 10344 –10349, 2001. Orlic D, Kajstura J, Chimenti S, Jakoniuk I, Anderson SM, Li B, Pickel J, McKay R, Nadal-Ginard B, Bodine DM, Leri A, and Anversa P. Bone marrow cells regenerate infarcted myocardium. Nature 410: 701–705, 2001. Orlic D, Kajstura J, Chimenti S, Bodine DM, Leri A, and Anversa P. Transplanted adult bone marrow cells repair myocardial infarcts in mice. Ann NY Acad Sci 938: 221–229, 2001. Oswald J, Boxberger S, Jorgensen B, Feldmann S, Ehninger G, Bornhauser M, and Werner C. Mesenchymal stem cells can be differentiated into endothelial cells in vitro. Stem Cells 22: 377–384, 2004. Pak HN, Qayyum M, Kim DT, Hamabe A, Miyauchi Y, Lill MC, Frantzen M, Takizawa K, Chen LS, Fishbein MC, Sharifi BG, Chen PS, and Makkar R. Mesenchymal stem cell injection induces cardiac nerve aprouting and increased tenacin expression in swine model of myocardial infarction. J Cardiovasc Electrophysiol 14: 841– 848, 2003. Peng CF, Wei Y, Levsky JM, McDonald TV, Childs G, and Kitsis RN. Microarray analysis of global changes in gene expression during cardiac myocyte differentiation. Physiol Genomics 9: 145–155, 2002. Perin EC, Dohmann HF, Borojevic R, Silva SA, Sousa AL, Mesquita CT, Rossi MI, Carvalho AC, Dutra HS, Dohmann HJ, Silva GV, Belem L, Vivacqua R, Rangel FO, Esporcatte R, Geng YJ, Vaughn WK, Assad JA, Mesquita ET, and Willerson JT. Transendocardial, autologous bone marrow cell transplantation for severe, chronic ischemic heart failure. Circulation 107: 2294 –2302, 2003. Petit I, Szyper-Kravitz M, Nagler A, Lahav M, Peled A, Habler L, Ponomaryov T, Taichman RS, Arenzana-Seisdedos F, Fujii N, Sandbank J, Zipori D, and Lapidot T. G-CSF induces stem cell mobilization by decreasing bone marrow SDF-1 and up-regulating CXCR4. Nat Immun 3: 687– 694, 2002. Pittenger MF, Mackay AM, Beck SC, Jaiswal RK, Douglas R, Mosca JD, Moorman MA, Simonetti DW, Craig S, and Marshak DR. Multillineage potential of adult human mesenchymal stem cells. Science 284: 143–147, 1999. Prosper F, Rabago G, Perez AA, Gavira JJ, Garcia MJ, Velloso MJG, Barba J, Sanchez PL, Canizo C, Marti JM, Hernandez M, Holgado NL, Gonzalez JM, Luengo CM, Alegria E, and Herreros J. AJP-Heart Circ Physiol • VOL 110. 111. 112. 113. 114. 115. 116. 117. 118. 119. 120. 121. 122. 123. 124. 125. 126. 127. 128. 129. Combine autologous myoblast transplantation with coronary revascularization in patients with non-acute myocardial infarction. J Heart Lung Transplant Suppl S62, 2004. Quaini F, Urbanek K, Beltrami AP, Finato N, Beltrami CA, NadalGinard B, Kajstura J, Leri A, and Anversa P. Chimerism of the transplanted heart. N Engl J Med 346: 5–15, 2002. Rezai N, Podor TJ, and McManus BM. Bone marrow cells in the repair and modulation of heart and blood vessels: emerging opportunities in native and engineered tissue and biomechanical materials. Artif Organs 28: 142–151, 2004. Sato T, Laver JH, and Ogawa M. Reversible expression of CD34 by murine hematopoietic stem cells. Blood 94: 2548 –2554, 1999. Sato Y, Goto Y, Sato S, Endo S, and Sohara Y. Continuous subcutaneous injection reduces polymorphonuclear leukocyte activation by granulocyte colony-stimulating factor. Am J Physiol Lung Cell Mol Physiol 286: L143–L148, 2004. Saito T, Kuang JG, Bittira B, Al-Kahlidi A, and Chiu RCJ. Xenotransplant cardiac chimera: immune tolerance of adult stem cells. Ann Thorac Surg 74: 19 –24, 2002. Saito T, Kuang JQ, Lin CC, and Chiu RC. Transcoronary implantation of bone marrow stromal cells ameliorates cardiac function after myocardial infarction. J Thorac Cardiovasc Surg 126: 114 –123, 2003. Sakaguchi G, SakakibaraY, Tambara K, Premaratne G, Lin X, Nishimura K, and Komeda M. Bone marrow cell enhances the efficacy of skeletal myoblast transplantation in rats with ischemic cadiomyopathy (Abstract). J Heart Lung Transplant 22: S79, 2003. Schuster MD, Kocher AA, Seki T, Martens TP, Xiang G, Homma S, and Itescu S. Myocardial neovascularization by bone marrow angioblasts results in cardiomyocyte regeneration. Am J Physiol Heart Circ Physiol 287: H525–H532, 2004. Scot EW. Stem cell plasticity or fusion: two approaches to the targeted cell therapy. Blood Cells Mol Dis 32: 65– 67, 2004. Sean JM, Wright DE, and Weissman LI. Cyclophosphamide/granulocyte colony-stimulating factor induces hematopoietic stem cells to proliferate prior to mobilization. Proc Natl Acad Sci USA 94: 1908 –1913, 1997. Seiler C, Pohl T, Wustmann K, Hutter D, Nicolet PA, Windecker S, Eberli FR, and Meier B. Promotion of collateral growth by granulocytemacrophage colony-stimulating factor in patients with coronary artery disease: a randomized, double-blind, placebo-controlled study. Circulation 104: 2012–2017, 2001. Shake JG, Gruber PJ, Baumgartner WA, Senechal G, Meyers J, Redmond JM, Pittenger MF, and Martin BJ. Mesenchymal stem cell implantation in a swine myocardial infarct model: engraftment and functional effects. Ann Thorac Surg 73: 1919 –1926, 2002. Shamsul BS, Aminuddin BS, Ng MH, and Ruszymah BH. Age and gender effect on the growth of bone marrow stromal cells in vitro. Med J Malaysia 59: 196 –197, 2004. Shi D, Reinecke H, Murry CE, and Torok-Storb B. Myogenic fusion of human bone marrow stromal cells, but not hematopoietic cells. Blood 104: 290 –294, 2004. Shintani S, Murohara T, Ikeda H, Ueno T, Honma T, Katoh A, Sasaki K, Shimada T, Oike Y, and Imaizumi T. Mobilization of endothelial progenitor cells in patients with acute myocardial infarction. Circulation 103: 2776 –2779, 2001. Siminiak T, Grygielska B, Jerzykowska O, Fiszer D, Kalmucki P, Rzezniczak J, and Kurpisz M. Autologous bone marrow stem cell transplantation in acute myocardial infarction-report of two cases. Kardiol Pol 59: 502–510, 2003. Stamm C, Westphal B, Kleine HD, Petzsch M, Kittner C, Klinge H, Schumichen C, Nienaber CA, Freund M, and Steinhoff G. Autologous bone marrow stem cell transplantation for myocardial regeneration. Lancet 361: 45– 46, 2003. Stamm C, Kleine HD, Westphal B, Petzsch M, Kittner C, Nienaber CA, Freund M, and Steinhoff G. CABG and bone marrow stem cell transplantation after myocardial infarction. Thorac Cardiovasc Surg 52: 152–158, 2004. Stenderup K, Justesen J, Clausen C, and Kassem M. Aging is associated with decreased maximal life span and accelerated senescence of bone marrow stromal cells. Bone 33: 919 –926, 2003. Strauer BE, Brehm M, Zeus T, Kostering M, Hernandez A, Sorg RV, Kogler G, and Wernet P. Repair of infarcted myocardium by autologous intracoronary mononuclear bone marrow cell transplantation in humans. Circulation 106: 1913–1918, 2002. 288 • JUNE 2005 • www.ajpheart.org Downloaded from http://ajpheart.physiology.org/ by 10.220.32.247 on April 29, 2017 97. BONE MARROW STEM CELLS FOR HEART Invited Review BONE MARROW STEM CELLS FOR HEART AJP-Heart Circ Physiol • VOL 145. 146. 147. 148. 149. 150. 151. 152. 153. 154. 155. 156. 157. 158. iologic and therapeutic implications. J Thorac Cardiovasc Surg 122: 699 –705, 2001. Wollert KC, Meyer GP, Lotz J, Ringes-Lichtenberg S, Lippolt P, Breidenbach C, Fichtner S, Korte T, Hornig B, Messinger D, Arseniev L, Hertenstein B, Ganser A, and Drexler H. Intracoronary autologous bone-marrow cell transfer after myocardial infarction: the BOOST randomised controlled clinical trial. Lancet 364: 141–148, 2004. Wright DE, Edward P, Bowman EP, Wagers AJ, Butcher EC, and Weissman IL. Hematopoietic Stem Cells are uniquely selective in their migratory response to chemokines. J Exp Med 195: 1145–1154 2002. Xu M, Wani M, Dai YS, Wang J, Yan M, Ayub A, and Ashraf M. Differentiation of bone marrow stromal cells into the cardiac phenotype requires intercellular communication with myocytes. Circulation 110: 2658 –2665, 2004. Xu W, Zhang X, Qian H, Zhu W, Sun X, Hu J, Zhou H, and Chen Y. Mesenchymal stem cells from adult human bone marrow differentiates into a cardiomyocyte phenotype in vitro. Exp Biol Med (Maywood) 229: 623– 631, 2004. Yan XQ, Briddell R, Hartley C, Stoney G, Samal B, and McNiece I. Mobilization of long-term hematopoietic reconstituting cells in mice by the combination of stem cell factor plus granulocyte colony-stimulating factor. Blood 84: 795–799, 1994. Yau TM, Tomita S, Weisel RD, Jia ZQ, Tumiati LC, Mickle DA, and Li RK. Beneficial effect of autologous cell transplantation on infarcted heart function: comparison between bone marrow stromal cells and heart cells. Ann Thorac Surg 75: 169 –176, 2003. Yeh ETH, Zhang S, Wu HD, Korbling M, Willerson JT, and Estrov Z. Transdifferentiation of human peripheral blood CD34⫹ enriched cell population into cardiomyocytes endothelial cells and smooth muscle cells in vivo. Circulation 108: 2070 –2073, 2003. Yin AH, Miraglia S, Zanjani ED, Almeida-Porada G, Ogawa M, Leary AG, Olweus J, Kearney J, and Buck DW. AC133, a novel marker for human hematopoietic stem and progenitor cells. Blood 90: 5002–5012, 1997. Ying QL, Nichols J, Evans EP, and Smith AG. Changing potency by spontaneous fusion. Nature 416: 545–548, 2002. Yoon KJ, Kim HO, Kwak YL, Kang SM, Jang YS, Lim SH, Ahn JY, and Li RK. Autologous bone marrow cell transplantation combined with off-pump coronary artery bypass grafting in human ischemic myocardium. Yonsei Med J 45, Suppl: S73, 2004. Yoon YS, Park JS, Tkebuchava T, Luedeman C, and Losordo DW. Unexpected severe calcification after transplantation of bone marrow cells in acute myocardial infarction. Circulation 109: 3154 –3157, 2004. Zhang S, Guo J, Zhang P, Liu Y, Jia Z, Ma K, Li W, Li L, and Zhou C. Long-term effects of bone marrow mononuclear cell transplantation on left ventricular function and remodeling in rats. Life Sci 74: 2853– 2864, 2004. Zhao LR, Duan WM, Reyes M, Keene CD, Verfaillie CM, and Low WC. Human bone marrow stem cells exhibit neural phenotypes and ameliorate neurological deficits after grafting into the ischemic brain of rats. Exp Neurol 174: 11–20, 2002. Zipori D. Mesenchymal stem cells: harnessing cell plasticity to tissue and organ repair. Blood Cells Mol Dis 33: 211–215, 2004. 288 • JUNE 2005 • www.ajpheart.org Downloaded from http://ajpheart.physiology.org/ by 10.220.32.247 on April 29, 2017 130. Takahashi T, Kalka C, Masuda H, Chen D, Silver M, Kearney M, Magner M, Isner JM, and Asahara T. Ischemia- and cytokine-induced mobilization of bone marrow-derived endothelial progenitor cells for neovascularization. Nat Med 5: 434 – 438, 1999. 131. Takano H, Ohtsuka M, Akazawa H, Toko H, Harada M, Hasegawa H, Nagai T, and Komuro I. Pleiotropic effects of cytokines on acute myocardial infarction: G-CSF as a novel therapy for acute myocardial infarction. Curr Pharm Des 9: 1121–1127, 2003. 132. Tang YL, Zhao Q, Zhang YC, Cheng L, Liu M, Shi J, Yang YZ, Pan C, Ge J, and Phillips MI. Autologous mesenchymal stem cell transplantation induce VEGF and neovascularization in ischemic myocardium. Regul Pept 117: 3–10, 2004. 133. Tao H and Ma DD. Evidence for transdifferentiation of human bone marrow-derived stem cells: recent progress and controversies. Pathology 35: 6 –13, 2003. 134. Terada N, Hamazaki T, Oka M, Hoki M, Mastalerz DM, Nakano Y, Meyer EM, Morel L, Petersen BE, and Scott EW. Bone marrow cells adopt the phenotype of other cells by spontaneous cell fusion. Nature 416: 542–545, 2002. 135. Theise ND and d’Inversno M. Understanding cell lineages as complex adaptive systems. Blood Cells Mol Dis 32: 17–20, 2004. 136. Togel F, Isaac J, and Westenfelder C. Hematopoietic stem cell mobilization-associated granulocytosis severely worsens acute renal failure. J Am Soc Nephrol 15: 1261–1267, 2004. 137. Toma C, Pittenger MF, Cahill KS, Byrne BJ, and Kessler PD. Human mesenchymal stem cells differentiate to a cardiomyocyte phenotype in the adult murine heart. Circulation 105: 93–98, 2002. 138. Tomita S, Li RK, Weisel RD, Mickle DA, Kim EJ, Sakai T, and Jia ZQ. Atologous transplantation of bone marrow cells improves damaged heart function. Circulation 100: II247–II256, 1999. 139. Tomita S, Mickle DA, Weisel RD, Jia ZQ, Tumiati LC, Allidina Y, Liu P, and Li RK. Improved heart function with myogenesis and angiogenesis after autologous porcine bone marrow stromal cell transplantation. J Thorac Cardiovasc Surg 123: 1132–1140, 2002. 140. Tomita S, Ishida M, Nakatani T, Fukuhara S, Hisashi Y, Ohtsu Y, Suga M, Yutani C, Yagihara T, Yamada K, and Kitamura S. Bone marrow is a source of regenerated cardiomyocytes in doxorubicininduced cardiomyopathy and granulocyte colony-stimulating factor enhances migration of bone marrow cells and attenuates cardiotoxicity of doxorubicin under electron microscopy. J Heart Lung Transplant 23: 577–584, 2004. 141. Tse HF, Kwong YL, Chan JKF, Lo G, Ho CL, and Lau CK. Angiogenesis in ischemic myocardium by intramyocardial autologous bone marrow mononuclear cell implantation. Lancet 361: 47– 49, 2003. 142. Velders GA, Pruijt JF, Verzaal P, van Os R, van Kooyk Y, Figdor CG, de Kruijf EJ, Willemze R, and Fibbe WE. Enhancement of G-CSF-induced stem cell mobilization by antibodies against the beta 2 integrins LFA-1 and Mac-1. Blood 100: 327–333, 2002. 143. Wang JS, Shum-Tim D, Galipeau J, Chedrawy E, Eliopoulos N, and Chiu RCJ. Marrow stromal cells for cellular cardiomyoplasty: Feasibility and potential clinical advantages. J Thorac Cardiovasc Surg 120: 999 –1006, 2000. 144. Wang JS, Shum-Tim D, Chedrawy E, and Chiu RCJ. The coronary delivery of marrow stromal cells for myocardial regeneration: pathophys- H2567