Efficacy Of Stem Cell Therapy Research Articles

Transplantation of cord blood mesenchymal stem cells as spheroids enhances vascularization.

Despite promising results from the therapeutic use of stem cells for treating ischemic diseases, the poor survival of cells transplanted into ischemic regions is one of the major problems that undermine the efficacy of stem cell therapy. Cord blood mononuclear cells (CBMNCs) are an alternative source of mesenchymal stem cells (MSCs) without disadvantages, such as the painful and invasive harvesting procedure, of MSCs derived from bone marrow or adipose tissue. In the present study, we investigated whether the angiogenic efficacy of cord blood mesenchymal stem cells (CBMSCs) can be enhanced by grafting as spheroids in a mouse hindlimb ischemia model. Human CBMSC (hCBMSC) spheroids were prepared by using the hanging-drop method. Mouse hindlimb ischemia was induced by excising the femoral artery and its branches. After surgery, the animals were divided into no-treatment, dissociated hCBMSC, and spheroid hCBMSC groups (n=8 per group) and received corresponding hCBMSC treatments. After surgery, the ischemic hindlimbs were monitored for 4 weeks, and then, the ischemic hindlimb muscles were harvested for histological analysis. Apoptotic signaling, angiogenesis-related signal pathways, and blood vessel formation were investigated in vitro and/or in vivo. The transplantation of hCBMSCs as spheroids into mouse ischemic hindlimbs significantly improved the survival of the transplanted cells by suppressing apoptotic signaling while activating antiapoptotic signaling. Furthermore, the transplantation of hCBMSCs as spheroids significantly increased the number of microvessels and smooth muscle α-actin-positive vessels in the ischemic limbs of mice, and attenuated limb loss and necrosis. Human CBMNC can be considered an alternative source of MSC, and spheroid-based hCBMSC delivery can be considered a simple and effective strategy for enhancing the therapeutic efficacy of hCBMSCs.

Protective effects of MCI-186 on transplantation of bone marrow stromal cells in rat ischemic stroke model

Transplantation of bone marrow stromal cells (BMSCs) is a potential therapy for ischemic stroke, but poor environmental conditions in brain lesions, such as insufficient nutrition and oxygen free radical toxicity, limit the efficacy of stem cell therapy. Here, we hypothesized that MCI-186, a free radical scavenger, would have protective effects on transplantation of BMSCs in a rat ischemia model. In vitro, flow cytometry showed the apoptotic rates of BMSCs after simulated ischemia–reperfusion (I/R) injury was significantly decreased when treated with MCI-186 (P<0.01). In vivo, rat transient middle cerebral artery occlusion (MCAO) model was established. Two separate MCAO groups were administered with either MCI-186 or phosphate-buffered solution (PBS) immediately after artery occlusion. MCI-186 significantly up-regulated the secretion of brain-derived neurotrophic factor, vascular endothelial growth factor and superoxide dismutase in ischemic brain, while malondialdehyde decreased and neuronal apoptosis was inhibited. Furthermore, another four MCAO groups were administered with either PBS, MCI-186, BMSCs (2×106) or a combination of MCI-186 and BMSCs. When compared with BMSCs or MCI-186 monotherapy, combination therapy significantly improved functional restoration, decreased infarct volume, and increased the number of engrafted-BMSCs and neurons in ischemic brain. The number of engrafted-BMSCs and neurons was significantly correlated with functional outcomes. This study suggests that MCI-186 may improve the environment of the injured brain, enhance the survival of engrafted-BMSCs and neurotization in ischemic brain and produce protective effects on BMSCs transplantation.

Abstract 21: Stiffness-Dependent Notch1 Activation Regulates Cardiogenic Differentiation of Cardiac Progenitor Cells

Cardiac progenitor cells (CPCs) are multipotent, self-renewing cells that can regenerate the myocardium and improve cardiac function in animal models of MI by cardiogenic differentiation. However, limited survival of stem/progenitor cells, myocardial scarring and fibrosis inhibit cardiac regeneration. Notch signaling promotes early cardiac development, cardiomyocyte survival and cardiac gene expression in circulating endothelial progenitor cells, mesenchymal stem cells and CPCs. As misregulation of Notch signaling during development is lethal due to cardiovascular defects, activating this critical pathway during cell transplantation could improve the efficacy of stem cell therapy. We investigated whether self-assembling peptide nanofiber hydrogels can be used to activate Notch1 signaling. The 16 amino acid self-assembling scaffold (RAD) was modified with a 20 amino acid peptide mimicking the active site of Notch1 ligand, Jagged1 (RJAG) or with the corresponding scrambled peptide (RSCR). To determine whether scaffold stiffness regulates Notch1 activation, CHO cells with Notch1 responsive YFP expression were cultured in scaffolds of 1-3% w/v in presence of RSCR or RJAG at a 1:10 ligand: scaffold ratio in 3D. Presence of the RJAG peptide (p&lt;0.01) and % concentration of the scaffold (p&lt;0.01) increased Notch1 activation significantly (n=5) indicating that RJAG mediated Notch1 activation in 3D is scaffold stiffness-dependent. Therefore, CPCs were cultured within 3D scaffolds (1-3% w/v; empty, scaffold +RJAG or RSCR) and cardiogenic gene expression was determined by qPCR. An increase in expression of early endothelial (Flk1, Flt1, vWF) and smooth muscle (sm22α, sm αactin) genes was observed in CPCs cultured in 3D scaffolds containing RJAG but not when cultured in 2D. These data show that Notch1 activation is dependent on ligand density and scaffold stiffness. Delivery of CPCs in JAG1 containing self-assembling scaffolds could be used to enhance therapeutic angiogenesis and improve cardiac function following myocardial infarction.

Polydopamine-mediated surface modification of scaffold materials for human neural stem cell engineering

Surface modification of tissue engineering scaffolds and substrates is required for improving the efficacy of stem cell therapy by generating physicochemical stimulation promoting proliferation and differentiation of stem cells. However, typical surface modification methods including chemical conjugation or physical absorption have several limitations such as multistep, complicated procedures, surface denaturation, batch-to-batch inconsistencies, and low surface conjugation efficiency. In this study, we report a mussel-inspired, biomimetic approach to surface modification for efficient and reliable manipulation of human neural stem cell (NSC) differentiation and proliferation. Our study demonstrates that polydopamine coating facilitates highly efficient, simple immobilization of neurotrophic growth factors and adhesion peptides onto polymer substrates. The growth factor or peptide-immobilized substrates greatly enhance differentiation and proliferation of human NSCs (human fetal brain-derived NSCs and human induced pluripotent stem cell-derived NSCs) at a level comparable or greater than currently available animal-derived coating materials (Matrigel) with safety issues. Therefore, polydopamine-mediated surface modification can provide a versatile platform technology for developing chemically defined, safe, functional substrates and scaffolds for therapeutic applications of human NSCs.

A novel method to delivery stem cells to the injured heart: spatially focused magnetic targeting strategy

Given the adult heart's minimal capacity for endogenous regeneration, cell therapy has emerged as a promising approach to the regeneration of damaged vascular and cardiac tissue after acute myocardial infarction and heart failure. However, systematic review suggests only mild improvement in global heart function, and high degree of heterogeneity among clinical trials [1]. The first prerequisite for cell therapy success is the engraftment and thus, homing of transplanted cells to the target area. Poor cell homing, retention and engraftment are major obstacles in achieving a significant functional benefit irrespective of the cell type or delivery route used. Data showed only 1–3% of the delivered cells were recruited at the infarct sites via intracoronary administration. The retention of cells in the heart is extremely low, even undetectable after a few weeks when administered by the intravenous route [2,3,4,5]. The predominant number of cells was found in non-targeting organs such as liver, spleen and lung. To induce migration and homing of transplanted cells to optimize the efficacy of cell-based therapies, much efforts have been made in identifying chemokine and its receptors (CXCR4/SDF-1 axis, et al.) in the last decades [6,7]. However, due to the extreme complicity of the ‘cell-extracellular matrix-cytokine’ network and the homing molecular mechanisms, the chemoattractant molecules-targeted method has been far away from being able to precisely and effectively regulate stem cell migrating to target tissue [8,9]. Magnetic targeting strategy, traditionally used in chemotherapy for tumour [10], had been introduced to localize magnetic nanoparticle-loaded cell delivery to target lesion in vivo in recent years [11,12,13,14,15,16,17]. The accumulation and retention of the magnetic responsive cells can be enhanced by using an external magnetic field produced by electromagnet, which is focused on the area of interest [18]. Cheng K. et al. [19 were the first to introduce magnetic targeting strategy to attract transplanted cells to the heart. Using a 1.3 Tesla magnet applied above the rat apex during the intramyocardial injection of magnetic responsive cardiosphere-derived cells, they found that cell retention and engraftment in the recipient hearts increased by approximately threefold compared to non-targeted cells. Chaudeurge A et al. 2011 adopted subcutaneous insertion of a magnet over the chest cavity during therapeutic intracavitary stem cell infusion, found that the average number of engrafted cells was significantly 10 times higher with than without magnetic targeting. This magnetically enhanced intracoronary cell delivery was confirmed by another study 2012. Thus, magnetic targeting is proved to enhance cell retention, engraftment and this novel method to improve cell therapy outcome offers the potential for clinical applications. However, the magnetic field has some inherent limitations as the magnetic flux density is maximal at the magnet pole face and cannot be focused at a distance from the magnet [10]. For conventional electromagnet therefore magnetically loaded cells are predominantly attracted to the surface of magnetic materials, and hard to be targeted to tissues localized deeper in the body. To promote the cell retention at targeting sites remote from the magnet surface, a greater magnetic force or invasive approaches (e.g. implant magnetized stent, magnetic particles or magnet at the target site) will be required. Magnetically loaded endothelial cells were homing to the magnetized stent deployed in rat arteries in the presence of a uniform magnetic field [12,13]. However, achievement of the cell engraftment necessary for therapeutic effects by using a ‘safe magnet force’ would be challenging. Moreover, it is not feasible that there could be the invasive implantation of a magnet or magnetized materials in parenchymatous organs such as heart. To overcome these limitations, it is of great significance to develope a magnetic field which can be focused at a distance from the magnet surface. Recently, we proposed that the spatially focused magnetic field is feasible in theoretical considerations [22]. Its deep capture property of this special magnetic field has been testified in our preliminary in vitro study [22,23]. The deep accumulation of magnetically loaded mesenchymal stem cells was observed while cells flowed through a tube served as a model of blood vessels in such a magnetic field. The cell capture efficiency was positively influenced by the magnetic flux density, and negatively influenced by the flow velocity. The capture efficiency reached 89.3% with 640 mT of the magnetic flux density, 38.4 T/m of the magnetic intensity gradient and 0.8 mm/sec. of flow velocity in our in vitro study [23].

Cotreatment with Darbepoetin and Granulocyte Colony-Stimulating Factor is Efficient to Recruit Proangiogenic Cell Populations in Patients with Acute Myocardial Infarction

To determine whether newer combination cytokine treatment with granulocyte colony-stimulating factor (G-CSF) and darbepoetin can improve efficacy of stem cell therapy, we evaluated safety and peripheral blood stem/progenitor cell (PBSC) mobilizing effects of combination cytokine in comparison with G-CSF alone in patients with acute myocardial infarction (AMI). We randomized 60 patients with AMI into two groups under 2:1 ratio; combination treatment with darbepoetin and G-CSF (n = 41: Combicytokine group) and the G-CSF alone (n = 19: G-CSF group). After coronary angioplasty, G-CSF was treated for 3 days with dose of 10 μg/kg/day in both groups. Only in the combicytokine group, additional single intravenous injection of 4.5 μg/kg of darbepoetin was administrated immediate after coronary angioplasty. Combination cytokine treatment was well tolerated as was G-CSF alone. PBSCs were obtained by apheresis for intracoronary infusion after completion of cytokine treatment and were analyzed by flow cytometry. The purity of proangiogenic cells was higher in combination cytokine group than the G-CSF group. Specifically, proportion of CD34(+)/KDR(+) endothelial progenitor cells, CD3(+)/CD31(+) angiogenic T cells and Tie2(+)/CXCR4(+) cells in apheresis products were higher in the combicytokine group. These meant that the combicytokine treatment recruited PBSCs in higher purity and fewer unwanted inflammatory cells than G-CSF alone in apheresis products. Combination treatment with darbepoetin and G-CSF is safe and more efficient to mobilize and recruit proangiogenic cells than G-CSF alone in patients with AMI. ( www.ClinicalTrials. gov identifier: NCT00501917).

Challenges for heart disease stem cell therapy

Cardiovascular diseases (CVDs) are the leading cause of death worldwide. The use of stem cells to improve recovery of the injured heart after myocardial infarction (MI) is an important emerging therapeutic strategy. However, recent reviews of clinical trials of stem cell therapy for MI and ischemic heart disease recovery report that less than half of the trials found only small improvements in cardiac function. In clinical trials, bone marrow, peripheral blood, or umbilical cord blood cells were used as the source of stem cells delivered by intracoronary infusion. Some trials administered only a stem cell mobilizing agent that recruits endogenous sources of stem cells. Important challenges to improve the effectiveness of stem cell therapy for CVD include: (1) improved identification, recruitment, and expansion of autologous stem cells; (2) identification of mobilizing and homing agents that increase recruitment; and (3) development of strategies to improve stem cell survival and engraftment of both endogenous and exogenous sources of stem cells. This review is an overview of stem cell therapy for CVD and discusses the challenges these three areas present for maximum optimization of the efficacy of stem cell therapy for heart disease, and new strategies in progress.

ASAPS/ASPS Position Statement on Stem Cells and Fat Grafting

You may have heard of the “stem cell face lift,” a “new technique using adult stem cells from the body’s own fat tissue [that] has been found to restore the plumpness, smoothness, and skin tightness of a more youthful face.”1 Or perhaps you have been interested in the “stem cell breast augmentation,” also known as “natural breast augmentation,” which “employs the latest technologic advances in fat harvesting, adult stem cell transfers and breast splinting technology to provide women the option of enlarging their breasts using their own fat.”2 These marketing claims, promoted as the latest cosmetic techniques based solidly on scientific fact, flood the airwaves and Internet. Although there is real hope within the plastic surgery community that stem cells may soon produce beneficial medical therapies to treat a variety of diseases, as of yet, such claims are not founded on the best science. One of the most untoward byproducts of such claims is that patient safety may be compromised by these “stem cell therapies.” Furthermore, the overall efficacy of these therapies remains unproven. Historically, in an effort to obtain the best scientific data on related subjects, the American Society of Plastic Surgeons and the American Society for Aesthetic Plastic Surgery have commissioned task forces to develop position statements.3–6 The purpose of these commissions is to pool society resources to determine, evaluate, and report on the best available data. Position statements on the best science and best practices recommendations may change over time in light of updated scientific discovery and long-term patient data. In similar fashion, the American Society for Aesthetic Plastic Surgery and the American Society of Plastic Surgeons commissioned a task force to research the evidence for the use of stem cells for aesthetic treatments. The joint statement below on stem cells and fat grafting represents the collective position of the American Society for Aesthetic Plastic Surgery and the American Society of Plastic Surgeons on the current state of the science. One overwhelming conclusion of the task force is that there is very limited evidence in terms of assessing the safety or efficacy of stem cell therapies in aesthetic medicine. Widespread use of the term “stem cell therapy” as applied to aesthetic procedures is not adequately supported by the clinical evidence at this time. Much more research needs to be conducted before any definitive statements can be made, and the task force encourages the collection and reporting of data on outcomes and safety by physicians performing stem cell therapies to advance the knowledge and science of stem cells. The American Society for Aesthetic Plastic Surgery, the American Society of Plastic Surgeons, and Plastic and Reconstructive Surgery and other scientific journals encourage plastic surgeons to read the position statement below and carefully join us in the scientific research of stem cell therapies. We urge you to submit your clinical results and experimental research in stem cells to the peer-reviewed plastic surgery journals, not only to help promote good science, but also to foster patient safety and best practices among your peers. In time, good science and longterm results will establish and confirm the truth about stem cell therapies, helping patients and plastic surgeons alike. Good science will then trump clever but unsubstantiated marketing, for the benefit of all.

Stem cell therapy for neonatal brain injury: Perspectives and Challenges

Cerebral palsy is a major health problem caused by brain damage during pregnancy, delivery, or the immediate postnatal period. Perinatal stroke, intraventricular hemorrhage, and asphyxia are the most common causes of neonatal brain damage. Periventricular white matter damage (periventricular leukomalacia) is the predominant form in premature infants and the most common antecedent of cerebral palsy. Stem cell treatment has proven effective in restoring injured organs and tissues in animal models. The potential of stem cells for self-renewal and differentiation translates into substantial neuroprotection and neuroregeneration in the animal brain, with minimal risks of rejection and side effects. Stem cell treatments described to date have used neural stem cells, embryonic stem cells, mesenchymal stem cells, umbilical cord stem cells, and induced pluripotent stem cells. Most of these treatments are still experimental. In this review, we focus on the efficacy of stem cell therapy in animal models of cerebral palsy, and discuss potential implications for current and future clinical trials.

Polyamidoamine dendrimer-conjugated quantum dots for efficient labeling of primary cultured mesenchymal stem cells

Monitoring of cells in vivo after transplantation could supply important information for determining the efficacy of stem cell therapy. The use of quantum dots (QDs) has several advantages for in vivo imaging, such as remarkable resistance to photo bleaching, high fluorescence efficiency, and size-tunable emission. After they are taken up by cells via endocytosis, QDs lose their fluorescence intensity in endosomes/lysosomes at low pH because the intensity cannot survive under acidic conditions. Moreover, the amount of QD uptake by mesenchymal stem cells (MSCs) is extremely small. Therefore, for effective labeling of MSCs and long observation of MSCs labeled by QDs in vivo, it is essential both to increase cellular uptake of QDs and to promote endosomal escape into the cytosol. The polyamidoamine (PAMAM) dendrimer had plenty of cationic charge, which promoted cellular uptake though electrostatic interactions, and a “buffering capacity,” which enhanced endosomal escape into the cytosol. In this study, QDs were modified with PAMAM dendrimer for the efficient labeling of MSCs by QDs. The uptake efficiency and cytosolic distribution of QDs in primary cultured MSCs were increased by the modification of the PAMAM dendrimer. The fluorescence intensity in MSCs labeled by PAMAM dendrimer-conjugated QDs lasted for a longer time in harvested culture plates or in cell-transplanted mice than that in MSCs labeled by non-conjugated QDs.

The use of stem cells to repair the injured lung

The structure of the lung is complex, it contains at least 40 different cell types. The lung interacts with the outside environment and the circulatory system. These features make the lung particularly susceptible to injury and disease. Stem cells with reparative properties can be found within the lung. Also, outside sources of stem cells can contribute to the repair of the injured lung. These include multipotent stem cells from the bone marrow and pluripotent stem cells derived from the early embryo or from adult cells, which are made to reverse to a pluripotent state by the addition of viral vectors or non-viral agents. For stem cells of outside sources to have a reparative function, the cells need to reach the injured lung, either by internal mobilization of stem cells from other parts of the body (e.g. bone marrow) or by administration of exogenous cell sources. Much research is currently undertaken to define the mechanisms by which stem cells repair the injured tissue. These include the possibility of engraftment of exogenous cells or the release of growth factors from the cells to aid repair. There is not as yet a clear consensus as to the mechanisms of repair. CURRENT RESEARCH AND TIMELINES: Interest is now focused on developing appropriate animal models to test the safety and efficacy of stem cell therapies and to understand the mechanisms by which stem cells undertake this task.

From High-Tech to Biotech Using Stem Cell and Gene Therapy to Treat Hearing Loss

From High-Tech to Biotech Using Stem Cell and Gene Therapy to Treat Hearing Loss

Another possible cell source for cardiac regenerative medicine: Reprogramming adult fibroblasts to cardiomyocytes and endothelial progenitor cells

Ischemic heart disease (IHD) is a significant burden to healthcare systems in the world despite substantial advances in risk modification, pharmacological therapy and revascularization therapy. Stem cell therapy is emerging as a novel therapeutic paradigm for myocardial repair. Several cell types including embryonic stem cells, adult stem cells and induced pluripotent stem (iPS) cells have been used for the treatment of ischemic heart disease. But all these engrafted cells must be systematically or locally administered after being expanded in vitro, the rare differentiation into cardiomyocytes and low cellular survival of engrafted cells also limited the efficacy of stem cell therapy. Recent research indicated that it was feasible to reprogramme one mature cell type into another cell type directly by introducing several transcription factors, which was called transdifferentiation. We speculate that cell reprogramming might provide potential new cell sources for therapeutic cardiac regeneration. For these reasons, we hypothesize that converting cardiac fibroblasts to cardiomyocytes and endothelial progenitor cells (EPCs) either in vivo or in vitro might be a possible way for future therapeutic cardiac regeneration. Furthermore we also analyzed the possible difficulties we might face on way to realize this hypothesis.

Apoptosis of mesenchymal stem cells induced by hydrogen peroxide concerns both endoplasmic reticulum stress and mitochondrial death pathway through regulation of caspases, p38 and JNK

Poor survival of mesenchymal stem cells (MSCs) compromised the efficacy of stem cell therapy for myocardial infarction. The increase of exogenous reactive oxygen species (ROS) in infracted heart is one of the important factors that challenged the survival of donor MSCs. In the study we aimed to evaluate the effect of oxidative stress on the cell death of MSCs and investigate its mechanisms in order to help with the identification of new biological compounds to reduce donor cells damage. Apoptosis of MSCs were evaluated with Hoechst 33342 staining and flow cytometry analysis. The mitochondrial membrane potential of MSCs was analyzed with JC-1 staining. Signaling pathways involved in H(2)O(2) induced apoptosis were analyzed with Western blot. H(2)O(2) induced apoptosis of MSCs in a dose- and time-dependent manner. H(2)O(2) induced apoptosis of MSCs via both endoplasmic reticulum (ER) and mitochondrial pathways rather than extrinsic apoptosis pathway. H(2)O(2) caused transient rather than sustained activation of p38 and JNK with no effect on ERK1/2 pathway. P38 was involved in the regulation of early apoptosis of MSCs while JNK was involved in the late apoptosis. P38 directed both ER stress and mitochondria death pathway in the early apoptosis. In conclusion, exogenous ROS was a major factor to induce apoptosis of MSCs. Both ER stress and mitochondria death pathway were involved in the apoptosis of MSCs. H(2)O(2) activated p38 that directed the above two pathways in the regulation of early apoptosis of MSCs while JNK was involved in the late apoptosis of MSCs.

Stem Cells: Clinical Trials Results The End of the Beginning or the Beginning of the End?

With increasing focus on the advance towards curative solutions, it is hard not to be excited by the potential of stem cell-based therapy. Application of the stem cell paradigm to cardiovascular medicine has fostered the evolution of novel approaches aimed at reversing injury caused by ischemic and non-ischemic cardiomyopathy. The feasibility and safety of stem cell use has been established in over 3,000 patients with either recent myocardial infarction or chronic organ failure. Nonetheless, the efficacy of stem cell therapy continues to remain in question. Initial clinical trials have focused on evaluation of multiple adult stem cell phenotypes in their unaltered, naíve state as a "first generation" resource for repair. Though significant strides in perfecting delivery of these biologics to the diseased heart have been achieved, the benefits with regard to myocardial functional recovery have been modest at best. One approach towards optimizing outcome may lie upon preemptive guidance of stem cells down the pathway of myocyte regeneration. As seen with pharmacotherapeutics in the last century, successful translation of "second generation" biotherapeutics in the 21(st) century will require close integration of a community of practice and science to ensure broad application of this emerging technology in the treatment of heart disease.

Autologous Myoblast Sheet Implantation for Severe Heart Failure

Human cardiac regeneration therapy has been performed by using various sources of stem cell. Myoblasts and bone marrow cells have been injected for patients with ischemic cardiomyopathy in our clinical trial and improved cardiac performance. We had examined the efficacy of stem cell therapy using tissue engineered sheet technique compared to needle injection. This technique has advantages such as the ability for treatment to large area, and less invasive for host heart such as lethal arrhythmia. In vivo, implantation of autologous myoblast sheet had improved cardiac function of ischemic or dilated cardiomyopathy models using rat, hamster, canine and porcine models. We also showed that myoblast sheets provided various factors inducing angiogenesis, hematopoietic cell recruitment and anti-apoptosis, following anti-remodeling. Thus, after approved by IRB of our institution, we have started the clinical trial of myoblast sheet implantation for DCM patients, and assessed the feasibility and efficacy for the first patient. In this patient, any sequelae including arrhythmia have not occurred after implantation, and the cardiac function showed recovery. Furthermore, we have investigated several improvement of this technology for the layered implantation for ischemic heart, for right heart failure, and another cell source to construct the sheet. Thus, stem cell sheet implantation could be safe and eligible as cardiac regeneration therapy.

Alveolar osseous defect in rat for cell therapy: preliminary report

To study were to reproduce an alveolar bone defect model in Wistar rats to be used for testing the efficacy of stem cell therapies. Additionally, we also aimed to determine the osteogenesis process of this osseous defect in the 1 month period post-surgery. The animals were randomly divided into two groups of 7 animals each. A gingivobuccal incision was made, and a bone defect of 28 mm(2) of area was performed in the alveolar region. Animals were killed at 2 weeks after surgery (n=7) and 4 weeks after surgery (n=7). The average area of the alveolar defect at time point of 2 weeks was 22.27 +/- 1.31 mm(2) and the average area of alveolar defect at time point of 4 weeks was 9.03 +/- 1.17 mm(2). The average amount of bone formation at time point of 2 weeks was 5.73 +/- 1.31 mm(2) and the average amount of bone formation at time point of 4 weeks was 19 +/- 1.17 mm(2). Statistically significant differences between the amount of bone formation at 2 weeks and 4 weeks after surgery were seen (p=0.003). The highest rate of ossification occurred mostly from 2 to 4 weeks after surgery. This observation suggests that 4 weeks after the bone defect creation should be a satisfactory timing to assess the potential of bone inductive stem cells to accelerate bone regeneration in Wistar rats.

Surface expression of CXCR4 in unrestricted somatic stem cells and its regulation by growth factors

Umbilical cord blood-derived USSCs (unrestricted somatic stem cells) have recently been considered as a potential source for stem cell therapy and transplantation due to their characteristics such as easy accessibility, low immunogenicity, self-renewing and multilineage differentiation potential. Stem cell homing is a key factor in successful transplantation, which is regulated by CXCR4 in stem cells. In this study, we evaluated the expression of CXCR4 in USSCs different passages. Moreover, the effect of VEGF (vascular endothelial growth factor) and IGF-1 (insulin-like growth factor 1) on its expression was assessed. It was shown that the expression of CXCR4 in USSCs decreased with the increase in passage number. It was also revealed that VEGF increased surface expression and mRNA level of CXCR4 in USSCs, while IGF-1 decreased its expression. When VEGF and IGF-1 were administered simultaneously, CXCR4 expression was increased, but the expression level was less than VEGF alone. Finally, it was shown that over-expression of CXCR4 enhanced the migratory capacity of USSCs. The increase of CXCR4 expression, here caused by VEGF in USSCs, can improve the efficacy of stem cell therapy and transplantation after long-term culture of stem cells before clinical use.

Rationale and design of the JUVENTAS trial for repeated intra-arterial infusion of autologous bone marrow-derived mononuclear cells in patients with critical limb ischemia

Critical limb ischemia (CLI) continues to form a substantial burden on Western healthcare. Many patients still face amputation as a last treatment option. Autologous bone marrow (BM)-derived cell administration has emerged as a potential new treatment, but proof for sustainable clinical effects of BM-derived cell therapy in CLI is still lacking. The JUVENTAS (reJUVenating ENdothelial progenitor cells via Transcutaneous intra-Arterial Supplementation) trial is the first randomized, placebo-controlled, double-blinded clinical trial on repeated intra-arterial BM mononuclear cell (MNC) infusion in 110 to 160 CLI patients, designed to provide definite proof for the efficacy of stem cell therapy. Primary outcome is the incidence of major amputation at 6 months. Inclusion of patients is well underway. If BM-MNC cells therapy is beneficial, it could become a novel treatment to prevent amputation in patients with CLI.

Migratory response of mesenchymal stem cells to macrophage migration inhibitory factor and its antagonist as a function of colony-forming efficiency

Human mesenchymal stem cells (MSCs) are capable of repairing pulmonary disorders, but their efficacy is limited by poor engraftment. A strategy is proposed to augment MSC migration to lung tissue by antagonizing macrophage migration inhibitory factor (MIF), a pro-inflammatory cytokine. Recombinant MIF (85 ng/ml) inhibited in vitro chemokinesis of multipotent MSCs by nearly 50 and 20% for donor preparations with colony-forming efficiencies of 22 +/- 4% and 66 +/- 3%, respectively (P < 0.05). The small-molecule MIF antagonist, (S,R)-3-(4-hydroxyphenyl)-4,5-dihydro-5-isoxazole acetic acid methyl ester (ISO-1, 85 microg/ml), restored MSC migration for all donors to levels found in the absence of MIF. At this concentration, ISO-1 increased migration to conditioned medium from bronchial epithelial cell cultures by >or=3-fold for all donor MSC preparations (P < 0.05). Transcript levels for the MIF receptor, CD74, in MSCs were independent of colony-forming efficiency. These data suggest that MIF and its antagonists may be relevant to the control of MSC homing and efficacy of stem cell therapies in a variety of clinical scenarios.