Autologous bone marrow transplantation in patients with subacute and chronic spinal cord injury

Targeted Intra-arterial Transplantation of Stem Cells to the Injured CNS is more Effective than Intravenous Administration: Engraftment is Dependent on Cell Type and Adhesion Molecule Expression

Stem cell transplantation procedures using intraparenchymal injections cause tissue injury in addition to associated surgical risks. Intravenous cell administration give engraftment in parenchymal lesions although the method has low efficacy and specificity. In pathological conditions with inflammation, such as traumatic brain injury, there is a transient up-regulation of ICAM-1 and VCAM-1 which might provide environmental cues for migration of stem cells from blood to parenchyma. The aim of this study was to i) analyze the effect of intra-arterial administration on cellular engraftment, ii) compare engraftment and side effects between three different stem cell systems, and iii) analyze gene expression in these three systems. We performed specific intra-arterial transplantations with human mesenchymal stem cells (hMSCs), human neural progenitor cells (hNPCs), and rat neural progenitor cells (rNPCs) in a rat model of traumatic brain injury. These results were compared to the intravenous route for each cell type, respectively. Analysis of engraftment and recipient characterization was performed by immunohistochemistry. We further characterized the different types of cells by microarray and RT-qPCR analysis. Specific intra-arterial transplantations produced significantly higher engraftment compared to intravenous transplantation with hMSCs and rNPCs. No engraftment was detected after intra-arterial or intravenous administration of hNPCs. Characterization of integrin expression indicated that CD49dVCAM-1 and possibly ICAM-1 interactions through CD18 and CD11a, respectively, are important for engraftment after intravascular cell administration. No side effects, such as thromboembolic complications, were detected. When translating stem cell therapies to clinical practice, the route of transplantation and the properties of the cell lines (homing, diapedesis, and migration) become important. This study supports the use of selective intra-arterial transplantation for improving engraftment after traumatic brain injury. In addition, we conclude that careful analysis of cells intended for local, intra-arterial transplantation with respect to integrin expression is important.

Clinical Achievements, Obstacles, Falsehoods, and Future Directions of Cell-Based Neurorestoratology

Neurorestoratology is a newborn and emerging distinct discipline in the neuroscience family. Its establishment will definitely speed up the advance of this promising frontier realm. A worldwide association for Neurorestoratology and several official journals covering this discipline have recently been set up. Clinical practice has demonstrated that the sequelae of damages and diseases of the CNS can be functionally restored to some degree. Obstacles that hinder the promising methods of Neurorestoratology to be translated from the bench to the bedside include political, governmental, religious, ethical, economic, and scientific factors or in most instances they work in combination. Falsehoods against the recognition of neurorestoratology include: 1) no therapeutic method is currently available that suggests that it is possible to repair, even partially, neurological functions; 2) according to the media, a cure will be very soon found for patients with severe spinal cord injury, brain trauma, and progressively deteriorated CNS degenerative diseases; 3) randomizing double blind control designed studies are the only gold standard for clinical study; self-comparison designed studies should be ignored and neglected. Future directions for neurorestoratology include the comparison and integration of current and upcoming available neurorestoration methods to look for the optimization regimes, and edit and publish clinical neurorestoratology treatment guidelines.

Neurological disorders and the potential role for stem cells as a therapy

Introduction Neurological disorders are routinely characterized by loss of cells in response to an injury or a progressive insult. Stem cells could therefore be useful to treat these disorders. Sources of data Pubmed searches of recent literature. Areas of agreement Stem cells exhibit proliferative capacity making them ideally suited for replacing dying cells. However, instead of cell replacement therapy stem cell transplants frequently appear to work via neurotrophic factor release, immunomodulation and upregulation of endogenous stem cells. Areas of controversy and areas timely for developing research Many questions remain with respect to the use of stem cells as a therapy, the answers to which will vary depending on the disorder to be treated and mode of action. Whereas the potential tumorigenic capability of stem cells is a concern, most studies do not support this notion. Further determination of the optimal cell type, and whether to perform allogeneic or autologous transplants warrant investigation before the full potential of stem cells can be realized. In addition, the use of stem cells to develop disease models should not be overlooked.

Concise review: Bone marrow for the treatment of spinal cord injury: mechanisms and clinical applications

Transplantation of bone marrow stem cells into spinal cord lesions enhances axonal regeneration and promotes functional recovery in animal studies. There are two types of adult bone marrow stem cell; hematopoietic stem cells (HSCs), and mesenchymal stem cells (MSCs). The mechanisms by which HSCs and MSCs might promote spinal cord repair following transplantation have been extensively investigated. The objective of this review is to discuss these mechanisms; we briefly consider the controversial topic of HSC and MSC transdifferentiation into central nervous system cells but focus on the neurotrophic, tissue sparing, and reparative action of MSC grafts in the context of the spinal cord injury (SCI) milieu. We then discuss some of the specific issues related to the translation of HSC and MSC therapies for patients with SCI and present a comprehensive critique of the current bone marrow cell clinical trials for the treatment of SCI to date.

The use of cellular magnetic resonance imaging to track the fate of iron-labeled multipotent stromal cells after direct transplantation in a mouse model of spinal cord injury

PURPOSE

The objective of this study was to track the fate of iron-labeled, multipotent stromal cells (MSC) after their direct transplantation into mice with spinal cord injuries using magnetic resonance imaging (MRI).

PROCEDURES

Mice with spinal cord injuries received a direct transplant of (1) live MSC labeled with micron-sized iron oxide particles (MPIO); (2) dead, MPIO-labeled MSC; (3) unlabeled MSC; or (4) free MPIO and were imaged at 3 T for 6 weeks after transplantation.

RESULTS

Live, iron-labeled MSC appeared as a well-defined region of signal loss in the mouse spinal cord at the site of transplant. However, the MR appearance of dead, iron-labeled MSC and free iron particles was similar and persisted for the 6 weeks of the study.

CONCLUSIONS

Iron-labeled stem cells can be detected and monitored in vivo after direct transplantation into the injured spinal cord of mice. However, the fate of the iron label is not clear. Our investigation indicates that caution should be taken when interpreting MR images after direct transplantation of iron-labeled cells.

Mesenchymal stem cell injection ameliorates chronic renal failure in a rat model

CKD (chronic kidney disease) has become a public health problem. The therapeutic approaches have been able to reduce proteinuria, but have not been successful in limiting disease progression. In this setting, cell therapies associated with regenerative effects are attracting increasing interest. We evaluated the effect of MSC (mesenchymal stem cells) on the progression of CKD and the expression of molecular biomarkers associated with regenerative effects. Adult male Sprague-Dawley rats subjected to 5/6 NPX (nephrectomy) received a single intravenous infusion of 0.5×106 MSC or culture medium. A sham group subjected to the same injection was used as the control. Rats were killed 5 weeks after MSC infusion. Dye tracking of MSC was followed by immunofluorescence analysis. Kidney function was evaluated using plasma creatinine. Structural damage was evaluated by H&E (haematoxylin and eosin) staining, ED-1 abundance (macrophages) and interstitial α-SMA (α-smooth muscle actin). Repairing processes were evaluated by functional and structural analyses and angiogenic/epitheliogenic protein expression. MSC could be detected in kidney tissues from NPX animals treated with intravenous cell infusion. This group presented a marked reduction in plasma creatinine levels and damage markers ED-1 and α-SMA (P<0.05). In addition, treated rats exhibited a significant induction in epitheliogenic [Pax-2, bFGF (basic fibroblast growth factor) and BMP-7 (bone morphogenetic protein-7)] and angiogenic [VEGF (vascular endothelial growth factor) and Tie-2] proteins. The expression of these biomarkers of regeneration was significantly related to the increase in renal function. Many aspects of the cell therapy in CKD remain to be investigated in more detail: for example, its safety, low cost and the possible need for repeated cell injections over time. Beyond the undeniable importance of these issues, what still needs to be clarified is whether MSC administration has a real effect on the treatment of this pathology. It is precisely to this point that the present study aims to contribute.

Early Immunomodulation by Intravenously Transplanted Mesenchymal Stem Cells Promotes Functional Recovery in Spinal Cord Injured Rats

Although intravenous administration of mesenchymal stem cells (MSCs) can enhance functional recovery after spinal cord injury (SCI), the underlying mechanisms have to be elucidated. In this study, we explored the mechanisms for functional recovery in SCI rats after intravenous transplantation of MSCs derived from human umbilical cord blood. Sprague-Dawley rats were randomly assigned to receive either MSCs (1 × 10(6) cells/0.5 ml) or PBS into the tail vein immediately after SCI. They were then evaluated by the Basso-Beattie-Bresnahan (BBB) locomotor rating scale weekly for 8 weeks and by somatosensory evoked potentials (SSEPs) 8 weeks after transplantation. MSC-treated rats showed a modest but significant improvement in BBB scores and latencies of SSEPs, compared with PBS controls. When human-specific Alu element was measured in the spinal cord, it was detected only 1 h after transplantation, suggesting transient engraftment of MSCs. Inflammatory cytokines were also determined using RT-PCR or Western blot in spinal cord extracts. In MSC-treated rats, the level of proinflammatory cytokine IL-1β was decreased, but that of anti-inflammatory cytokine IL-10 was increased. MSCs also immediately suppressed IL-6 at 1 h posttransplantation. However, the response of IL-6, which has an immunoregulatory role, was increased 1-3 days after transplantation. In addition, we quantified microglia/macrophage stained with Iba-1 around the damaged spinal cord using immunohistochemistry. A proportion of activated microglia and macrophages in total Iba-1(+) cells was significantly decreased in MSC-treated rats, compared with PBS controls. These results suggest that early immunomodulation by intravenously transplanted MSCs is a potential underlying mechanism for functional recovery after SCI.

Long term follow-up of the endovascular trans-vessel wall technique for parenchymal access in rabbit with full clinical integration

Objective

Endovascular techniques are providing options to surgical/percutaneous cell transplantation methods. Some cells, e.g. insulin producing cells, are not suitable for intra-luminal transplantation and for such cells, other options must be found. We have constructed a “nanocatheter” with a penetrating tip for vessel perforation, thereby creating a working channel for parenchymal access by endovascular technique. To finish the procedure safely, the distal tip is detached to provide a securing plug in the vessel wall defect.

Materials and Methods

We have performed interventions with full clinical integration in the superior mesenteric artery (SMA), the subclavian artery and the external carotid artery in rabbits. No hemorrhagic- or thromboembolic events occurred during the procedure. Stenosis formation and distal embolisation were analyzed by angiography and macroscopic inspection during autopsy at five, 30 and 80 days. All animals and implanted devices were also evaluated by micro-dissections and histochemical analysis.

Results

In this study we show safety data on the trans-vessel wall technique by behavioral, angiographical and histological analysis. No stenosis formation was observed at any of the follow-up time points. No animals or organs have shown any signs of distress due to the intervention. Histological examination showed no signs of hemorrhage, excellent biocompatibility with no inflammation and a very limited fibrous capsule formation around the device, comparable to titanium implants. Further, no histological changes were detected in the endothelia of the vessels subject to intervention.

Conclusions

The trans-vessel wall technique can be applied for e.g. cell transplantations, local substance administration and tissue sampling with low risk for complications during the procedure and low risk for hemorrhage, stenosis development or adverse tissue reactions with an 80 days follow-up time. The benefit should be greatest in organs that are difficult or risky to reach with surgical techniques, such as the pancreas, the CNS and the heart.

Autologous mesenchymal stem cells in chronic spinal cord injury

Spinal cord injury (SCI) occurs in the most productive part of life. Treatment options for treatment of chronic SCI are few and have limited impact on clinical outcome. Central nervous system (CNS) has limited intrinsic regeneration capability. The study included patients with chronic complete SCI. Previously harvested autologous mesenchymal stem cells were administered at the site of injury after a laminectomy. Follow-up was done by a neutral examiner not involved in the surgery every 3 months. One patient had improvement in motor power. Two patients had a patchy improvement in pin prick sensation below the level of injury. Three different, progressively increasing doses did not result in improvement in the clinical outcome. Though the administration of allogenic human mesenchymal stem cells is safe in patients with SCI, it may not be efficacious; especially in patients with chronic SCI.

Enhancing CNS repair in neurological disease: challenges arising from neurodegeneration and rewiring of the network

Repair of the central nervous system (CNS) constitutes an integral part of treating neurological disease and plays a crucial role in restoring CNS architecture and function. Distinct strategies have been developed to reconstruct the damaged neural tissue, with many tested preclinically in animal models. We review cell replacement-based repair strategies. By taking spinal cord injury, cerebral ischaemia and degenerative CNS disorders as examples for CNS repair, we discuss progress and potential problems in utilizing embryonic stem cells and adult neural/non-neural stem cells to repair cell loss in the CNS. Nevertheless, CNS repair is not simply a matter of cell transplantation. The major challenge is to induce regenerating neural cells to integrate into the neural network and compensate for damaged neural function. The neural cells confront an environment very different from that of the developmental stage in which these cells differentiate to form interwoven networks. During the repair process, one of the challenges is neurodegeneration, which can develop from interrupted innervations to/from the targets, chronic inflammation, ischaemia, aging or idiopathic neural toxicity. Neurodegeneration, which occurs on the basis of a characteristic vascular and neural web, usually presents as a chronically progressive process with unknown aetiology. Currently, there is no effective treatment to stop or slow down neurodegeneration. Pathological changes from patients with Alzheimer's disease, Parkinson's disease and amyotrophic lateral sclerosis indicate a broken homeostasis in the CNS. We discuss how the blood-brain barrier and neural networks are formed to maintain CNS homeostasis and their contribution to neurodegeneration in diseased conditions. Another challenge is that some inhibitors produced by CNS injury do not facilitate the regenerating neural cells to incorporate into a pre-existing network. We review glial responses to CNS injury. Of note, the reactive astrocytes not only encompass the lesions/pathogens but may also form glial scars to impede regenerating axons from traversing the lesions. In addition, myelin debris can prevent axon growth. Myelination enables saltatory transduction of electrical impulses along axonal calibers and actually provides trophic support to stabilize the axons. Therefore, repair strategies should be designed to promote axonal growth, myelination and modulate astrocytic responses. Finally, we discuss recent progress in developing human monoclonal IgMs that regulate CNS homeostasis and promote neural regeneration.

Neuronal plasticity of human Wharton's jelly mesenchymal stromal cells to the dopaminergic cell type compared with human bone marrow mesenchymal stromal cells

BACKGROUND AIMS

Mesenchymal stromal cells (MSC) derived from Wharton's jelly (WJ) of the umbilical cord are increasingly gaining prominence as substitutes for bone marrow (BM) MSC. While MSC isolated from different tissue sources may share common mesenchymal properties, the difference in their plasticity to individual lineages is ill-defined. Thus the focus of this study was to estimate the neuronal plasticity of WJ MSC to the dopaminergic (DA) cell type in comparison with BM MSC.

METHODS

For neuronal differentiation, MSC were exposed to developmentally relevant cues for midbrain DA neurons: sonic hedgehog (SHH) and fibroblast growth factor 8 (FGF8), along with basic fibroblast growth factor (bFGF).

RESULTS

Naive MSC from both sources constitutively expressed neuronal markers. Flow cytometry data revealed that the control WJ MSC shared a signature similar to BM MSC for early neuronal markers (nestin, musashi12 and A2B5) and DA-specific markers [tyrosine hydroxylase (TH) and Nuclear Receptor related protein 1 (Nurr1) but differed for mature neuronal proteins [β-tubulin III and microtubule-associated protein 2 (Map2ab)]. Similar populations of cells in both sources of MSC were positive for the SHH receptors [patched (PTCH) and smoothened (SMO)]. In induced BM and WJ MSC, real-time reverse transcriptase (RT)-polymerase chain reaction (PCR) analysis showed similar levels of DA-related transcription factors Nurr1 and Engrailed (En) 1. Immunocytochemical and flow cytometry analysis showed an increase in mature neuronal marker Map2ab. Kv4.2, a K(+) channel marker, was observed only in the induced MSC. Induced MSC also expressed several DA-specific markers, TH, dopamine and cyclic AMP regulated phosphoprotein (DARPP) 32, paired-like homeodomain transcription factor (PitX) 3 and vesicular monoamine transporter (VMAT) 2, in comparable levels between the two sources. The efficiency (c. 65%) of transdifferentiation of WJ MSC to TH-positive cells was similar to that of induced BM MSC. Constitutive and inducible release of dopamine was found to be similar between induced BM and WJ MSC, as measured by dopamine enzyme-linked immunosorbent assay (ELISA). Interestingly, an adenosine triphosphate (ATP)-stimulated change in intracellular Ca(2+) was observed in both control and induced MSC, but only the induced MSC was capable of releasing dopamine.

CONCLUSIONS

Our data demonstrate that MSC from the two different sources respond similarly to inductive cues to differentiate terminally to a DA cell type, and the neuronal plasticity of human WJ MSC is comparable with that of BM MSC.

Flt3 ligand synergizes with granulocyte-colony-stimulating factor in bone marrow mobilization to improve functional outcome after spinal cord injury in the rat

BACKGROUND AIMS

The effect of granulocyte-colony-stimulating factor (G-CSF) and/or the cytokine fms-like thyrosin kinase 3 (Flt3) ligand on functional outcome and tissue regeneration was studied in a rat model of spinal cord injury (SCI).

METHODS

Rats with a balloon-induced compression lesion were injected with G-CSF and/or Flt3 ligand to mobilize bone marrow cells. Behavioral tests (Basso-Beattie-Bresnahan and plantar test), blood counts, morphometric evaluation of the white and gray matter, and histology were performed 5 weeks after SCI.

RESULTS

The mobilization of bone marrow cells by G-CSF, Flt3 ligand and their combination improved the motor and sensory performance of rats with SCI, reduced glial scarring, increased axonal sprouting and spared white and gray matter in the lesion. The best results were obtained with a combination of G-CSF and Flt3. G-CSF alone or in combination with Flt3 ligand significantly increased the number of white blood cells, but not red blood cells or hemoglobin content, during and after the time-course of bone marrow stimulation. The combination of factors led to infiltration of the lesion by CD11b(+) cells.

CONCLUSIONS

The observed improvement in behavioral and morphologic parameters and tissue regeneration in animals with SCI treated with a combination of both factors could be associated with a prolonged time-course of mobilization of bone marrow cells. The intravenous administration of G-CSF and/or Flt3 ligand represents a safe and effective treatment modality for SCI.

Strategies for spinal cord repair after injury: a review of the literature and information

INTRODUCTION

Thanks to the Internet, we can now have access to more information about spinal cord repair. Spinal cord injured (SCI) patients request more information and hospitals offer specific spinal cord repair medical consultations.

OBJECTIVE

Provide practical and relevant elements to physicians and other healthcare professionals involved in the care of SCI patients in order to provide adequate answers to their questions.

METHOD

Our literature review was based on English and French publications indexed in PubMed and the main Internet websites dedicated to spinal cord repair.

RESULTS

A wide array of research possibilities including notions of anatomy, physiology, biology, anatomopathology and spinal cord imaging is available for the global care of the SCI patient. Prevention and repair strategies (regeneration, transplant, stem cells, gene therapy, biomaterials, using sublesional uninjured spinal tissue, electrical stimulation, brain/computer interface, etc.) for the injured spinal cord are under development. It is necessary to detail the studies conducted and define the limits of these new strategies and benchmark them to the realistic medical and rehabilitation care available to these patients.

CONCLUSION

Research is quickly progressing and clinical trials will be developed in the near future. They will have to answer to strict methodological and ethical guidelines. They will first be designed for a small number of patients. The results will probably be fragmented and progress will be made through different successive steps.

Autologous bone marrow stromal cell transplantation for central nervous system disorders - recent progress and perspective for clinical application

There is increasing evidence that the transplanted BMSC significantly promote functional recovery after CNS damage in the animal models of various kinds of CNS disorders, including cerebral infarct, traumatic brain injury and spinal cord injury. However, there are several shortages of information when considering clinical application of BMSC transplantation for patients with CNS disorders. In this review, therefore, we discuss what we should clarify to establish cell transplantation therapy as the scientifically proven entity in clinical situation and describe our recent works for this purpose. The BMSC have the ability to alter their gene expression profile and phenotype in response to the surrounding circumstances and to protect the neurons by producing some neurotrophic factors. They also promote neurite extension and rebuild the neural circuits in the injured CNS. The BMSC can be expanded in vitro using the animal serum-free medium. Pharmacological modulation may accelerate the in vitro proliferation of the BMSC. Using in vivo optical imaging technique, the transplanted BMSC can non-invasively be tracked in the living animals for at least 8 weeks after transplantation. It is urgent issues to develop clinical imaging technique to track the transplanted cells in the CNS and evaluate the therapeutic significance of BMSC transplantation in order to establish it as a definite therapeutic strategy in clinical situation in the future.

HPMA-RGD hydrogels seeded with mesenchymal stem cells improve functional outcome in chronic spinal cord injury

Chronic spinal cord injury (SCI) is characterized by tissue loss and a stable functional deficit. While several experimental therapies have proven to be partly successful for the treatment of acute SCI, treatment of chronic SCI is still challenging. We studied whether we can bridge a chronic spinal cord lesion by implantation of our newly developed hydrogel based on 2-hydroxypropyl methacrylamide, either alone or seeded with mesenchymal stem cells (MSCs), and whether this treatment leads to functional improvement. A balloon-induced compression lesion was performed in adult 2-month-old male Wistar rats. Five weeks after injury, HPMA-RGD hydrogels [N-(2-hydroxypropyl)-methacrylamide with attached amino acid sequences--Arg-Gly-Asp] were implanted into the lesion, either with or without seeded MSCs. Animals with chronic SCI served as controls. The animals were behaviorally tested using the Basso–Beattie-Breshnahan (BBB) (motor) and plantar (sensory) tests once a week for 6 months. Behavioral analysis showed a statistically significant improvement in rats with combined treatment, hydrogel and MSCs, compared with the control group (P < 0.05). Although a tendency toward improvement was found in rats treated with hydrogel only, this was not significant. Subsequently, the animals were sacrificed 6 months after SCI, and the spinal cord lesions evaluated histologically. The combined therapy (hydrogel with MSCs) prevented tissue atrophy (P < 0.05), and the hydrogels were infiltrated with axons myelinated with Schwann cells. Blood vessels and astrocytes also grew inside the implant. MSCs were present in the hydrogels even 5 months after implantation. We conclude that 5 weeks after injury, HPMA-RGD hydrogels seeded with MSCs can successfully bridge a spinal cord cavity and provide a scaffold for tissue regeneration. This treatment leads to functional improvement even in chronic SCI.

Experimental reconstruction of the injured spinal cord

Injury to the spinal cord, with its pathological sequelae, results in a permanent neurological deficit. With currently available tools at hand, there is very little that clinicians can do to treat such a condition with the view of helping patients with spinal cord injury (SCI). On the other hand, in the last 20 years experimental research has brought new insights into the pathophysiology of spinal cord injury; we can divide the time course into 3 phases: primary injury (the time of traumatic impact and the period immediately afterwards), the secondary phase (cell death, inflammation, ischemia), and the chronic phase (scarring, demyelination, cyst formation). Increased knowledge about the pathophysiology of SCI can stimulate the development of new therapeutic modalities and approaches, which may be feasible in the future in clinical practice. Some of the most promising experimental therapies include: neurotrophic factors, enzymes and antibodies against inhibitory molecules (such as Nogo), activated macrophages, stem cells and bridging scaffolds. Their common goal is to reconstitute the damaged tissue in order to recover the lost function. In the current review, we focus on some of the recent developments in experimental SCI research.

Feasibility of combination allogeneic stem cell therapy for spinal cord injury: a case report

Cellular therapy for spinal cord injury (SCI) is overviewed focusing on bone marrow mononuclear cells, olfactory ensheathing cells, and mesenchymal stem cells. A case is made for the possibility of combining cell types, as well as for allogeneic use. We report the case of 29 year old male who suffered a crush fracture of the L1 vertebral body, lacking lower sensorimotor function, being a score A on the ASIA scale. Stem cell therapy comprised of intrathecal administration of allogeneic umbilical cord blood ex-vivo expanded CD34 and umbilical cord matrix MSC was performed 5 months, 8 months, and 14 months after injury. Cell administration was well tolerated with no adverse effects observed. Neuropathic pain subsided from intermittent 10/10 to once a week 3/10 VAS. Recovery of muscle, bowel and sexual function was noted, along with a decrease in ASIA score to "D". This case supports further investigation into allogeneic-based stem cell therapies for SCI.

Clinical and experimental advances in regeneration of spinal cord injury

Spinal cord injury (SCI) is one of the major disabilities dealt with in clinical rehabilitation settings and is multifactorial in that the patients suffer from motor and sensory impairments as well as many other complications throughout their lifetimes. Many clinical trials have been documented during the last two decades to restore damaged spinal cords. However, only a few pharmacological therapies used in clinical settings which still have only limited effects on the regeneration, recovery speed, or retraining of the spinal cord. In this paper, we will introduce recent clinical trials, which performed pharmacological treatments and cell transplantations for patients with SCI, and evaluate recent in vivo studies for the regeneration of injured spinal cord, including stem-cell transplantation, application of neurotrophic factors and suppressor of inhibiting factors, development of biomaterial scaffolds and delivery systems, rehabilitation, and the combinations of these therapies to evaluate what can be appropriately applied in the future to the patients with SCI.

Nontoxic genetic engineering of mesenchymal stem cells using serum-compatible pullulan-spermine/DNA anioplexes

Genetic modification of stem cells could be applied to initiate/enhance their secretion of therapeutic molecules, alter their biological properties, or label them for in vivo tracking. We recently developed a negatively charged gene carrier ("anioplex") based on pullulan-spermine, a conjugate prepared from a natural polysaccharide and polyamine. In rat mesenchymal stem cells (MSCs), anioplex-derived reporter gene activity was comparable to or exceeded that obtained using a commercial cationic lipid reagent. Transfection in the growth medium with 15% serum and antibiotics was approximately sevenfold more effective than in serum-free conditions. Cytotoxicity was essentially indiscernible after 24 h of anioplex transfection with 20 μg/mL DNA, in contrast to cationic lipid transfection that resulted in 40%-60% death of target MSCs. Anioplex-derived reporter gene activity persisted throughout the entire 3-week study, with post-transfection MSCs appearing to maintain osteogenic, adipogenic, and chondrogenic multipotency. In particular, chondrogenic pellet formation of differentiating human MSCs was significantly inhibited after lipofection but not after aniofection, which further indicates the biological inertness of pullulan-spermine/DNA anioplexes. Collectively, these data introduce a straightforward technology for genetic engineering of adult stem/progenitor cells under physiological niche-like conditions. Moreover, reporter gene activity was observed in rat spinal cords after minimally invasive intrathecal implantation, suggesting effective engraftment of donor MSCs. It is therefore plausible that anioplex-transfected MSCs or other stem/progenitor cells with autologous potential could be applied to disorders such as neurotrauma or neuropathic pain that involve the spinal cord and brain.

The effect of mesenchymal stem cell transplantation on the recovery of bladder and hindlimb function after spinal cord contusion in rats

Background

Mesenchymal stem cells are widely used for transplantation into the injured spinal cord in vivo model and for safety, many human clinical trials are continuing to promote improvements of motor and sensory functions after spinal cord injury. Yet the exact mechanism for these improvements remains undefined. Neurogenic bladder following spinal cord injury is the main problem decreasing the quality of life for patients with spinal cord injury, but there are no clear data using stem cell transplantation for the improvement of neurogenic bladder for in vivo studies and the clinical setting.

The purpose of this study was to delineate the effect of human mesenchymal stem cell (hMSCs) transplantation on the restoration of neurogenic bladder and impaired hindlimb function after spinal cord contusion of rats and the relationship between neurotrophic factors such as brain derived neurotrophic factor (BDNF) and neurotrophin-3 (NT-3) and bladder and hindlimb functions.

Results

Modified moderate contusion injury were performed on the thoracic spinal cord of Sprague-Dawley rats using MASCIS impactor and hMSCs, human fibroblasts or phosphate-buffered saline were transplanted into injured spinal cord 9 days after injury for hMSC and two control groups respectively. Ladder test showed more rapid restoration of hindlimb function in hMSC group than in control group, but Basso, Beattie, and Bresnahan score and coupling score were not different significantly among hMSC and two control groups. Neurogenic bladder was not improved in either group. ED1 positive macrophages were significantly reduced in hMSC group than in two control groups, but ELISA and RT-PCR studies revealed BDNF and NT-3 levels in spinal cord and bladder were not different among hMSC and two control groups regardless the experimental duration.

Conclusion

hMSC transplantation was effective in reducing inflammatory reaction after spinal cord contusion of rats but not sufficient to recover locomotor and bladder dysfunction. BDNF and NT-3 levels in the spinal cord and bladder were not increased 28 and 56 days after hMSC transplantation.

Case control series of intrathecal autologous bone marrow mesenchymal stem cell therapy for chronic spinal cord injury

BACKGROUND

Autologous bone marrow mesenchymal cells that include stem cells (MSCs) are a clinically attractive cellular therapy option to try to treat severe spinal cord injury (SCI).

OBJECTIVE

To study the possible value of MSCs injected intrathecally to enhance rehabilitation.

METHODS

This case control, convenience sample included 64 patients, at a mean of 3.6 years after SCI. Forty-four subjects received monthly intrathecal autologous MSCs for 6 months and 20 subjects, who would not agree to the procedures, served as controls. All subjects received rehabilitation therapies 3 times weekly. Subjects were evaluated at entry and at 12 months after completing the 6-months intervention. By the ASIA Impairment Scale, ASIA grading of completeness of injury, Ashworth Spasticity Scale, Functional Ambulation Classification, and bladder and bowel control questionnaire.

RESULTS

No differences were found in baseline measures and descriptors between the MSC group and control group. Although a higher percentage of the MSC group increased motor scores by 1-2 points and changed from ASIA A to B, no significant between-group improvements were found in clinical measures. Adverse effects of cells included spasticity and, in 24 out of the 43 patients developed neuropathic pain. One subject with a history of post-infectious myelitis developed encephalomyelitis after her third injection.

CONCLUSION

Autologus MSCs may have side effects and may be contraindicated in patients with a history of myelitis. Their utility in treating chronic traumatic SCI needs further study in pre-clinical models and in randomized controlled trials before they should be offered to patients.

Stem cell therapies for spinal cord injury

Stem cell therapy is a potential treatment for spinal cord injury (SCI), and a variety of different stem cell types have been evaluated in animal models and humans with SCI. No consensus exists regarding the type of stem cell, if any, that will prove to be effective therapeutically. Most data suggest that no single therapy will be sufficient to overcome all the biological complications caused by SCI. Rationales for therapeutic use of stem cells for SCI include replacement of damaged neurons and glial cells, secretion of trophic factors, regulation of gliosis and scar formation, prevention of cyst formation, and enhancement of axon elongation. Most therapeutic approaches that use stem cells involve implantation of these cells into the spinal cord. The attendant risks of stem cell therapy for SCI--including tumor formation, or abnormal circuit formation leading to dysfunction--must be weighed against the potential benefits of this approach. This Review will examine the biological effects of SCI, the opportunities for stem cell treatment, and the types of stem cells that might be used therapeutically. The limited information available on the possible benefits of stem cell therapy to humans will also be discussed.

Co-transplantation of olfactory ensheathing glia and mesenchymal stromal cells does not have synergistic effects after spinal cord injury in the rat

BACKGROUND AIMS

Olfactory ensheathing glia (OEG) and mesenchymal stromal cells (MSC) are suitable candidates for transplantation therapy of spinal cord injury (SCI). Both facilitate functional improvement after SCI by producing trophic factors and cytokines. In this study, the co-transplantation of both types of cells was studied to clarify their additive and/ or synergistic effects on SCI.

METHODS

A balloon-induced compression lesion was used to produce SCI in rats. OEG, MSC or both OEG and MSC (3 x 10(5) cells of each cell type) were implanted by intraspinal injection 1 week after SCI. The effect of transplantation was assessed using behavioral, electrophysiologic and histologic methods.

RESULTS

Hindlimb function was examined with Basso, Beattie and Bresnahan (BBB) and Plantar tests. Improvement was found in all three groups of transplanted rats with different time-courses, but there was no significant difference among the groups at the end of the experiment. Motor-evoked potentials after SCI decreased in amplitude from 7 mV to 10 microV. Linear regression analysis showed a modest recovery in amplitude following transplantation, but no change in the control rats. Histologic findings showed that the white and gray matter were significantly spared by transplantation after SCI.

CONCLUSIONS

Functional improvement was achieved with transplantation of OEG and/or MSC, but the co-transplantation of OEG and MSC did not show synergistic effects. The poor migration of OEG and MSC might prevent their concerted action. Pre-treatment with a Rho antagonist and a combination of intraspinal and intravenous injection of the cells might be beneficial for SCI therapy.

Bone marrow stromal cell transplantation for treatment of sub-acute spinal cord injury in the rat

Bone marrow stromal cells (BMSCs) have been studied as effective transplants for the treatment of spinal cord injury (SCI). Our previous study showed that BMSCs infused into the cerebrospinal fluid (CSF) exhibited distinct effects on the recovery of acute SCI. The present study examined the effects of BMSCs in sub-acute SCI (2weeks post-injury) by transplanting them directly into the lesion. The spinal cord was crush-injured at the Th8-9 level in rats, and 2weeks later, cultured BMSCs (5x10(5)) derived from GFP-transgenic rats of the same strain were transplanted into the lesion. Tissue repair and nerve regeneration were examined by immunohistochemistry and electron microscopy. GFP-labeled BMSCs survived as cell assemblies in the spinal cord for 1-2weeks after transplantation. The dorsal side of BMSC assemblies in the spinal cord usually showed an expanded GFAP-negative, astrocyte-devoid area, in which extracellular matrices including collagen fibrils were deposited. Numerous regenerating axons associated with Schwann cells grew out through such astrocyte-devoid extracellular matrices. Ascending (CGRP-containing) and descending (5HT- and TH-containing) axons were included in these regenerating axons. Regenerated axons were myelinated by Schwann cells beyond 2weeks post-transplantation. Cavity formation was reduced in the cell transplantation group. Locomotory behavior assessed by the BBB scale improved to 9.8 points in the cell transplantation group, while it was to 5.5-5.7 in the control. BMSC transplantation into lesions of advanced SCI has markedly beneficial effects on tissue repair and axonal outgrowth, leading to improved locomotion in rats.

Nanotechnology for treatment of stroke and spinal cord injury

The use of nanotechnology in cell therapy and tissue engineering offers promising future perspectives for brain and spinal cord injury treatment. Stem cells have been shown to selectively target injured brain and spinal cord tissue and improve functional recovery. To allow cell detection, superparamagnetic iron-oxide nanoparticles can be used to label transplanted cells. MRI is then a suitable method for the in vivo tracking of grafted cells in the host organism. CNS, and particularly spinal cord, injury is accompanied by tissue damage and the formation of physical and biochemical barriers that prevent axons from regenerating. One aspect of nanomedicine is the development of biologically compatible nanofiber scaffolds that mimic the structure of the extracellular matrix and can serve as a permissive bridge for axonal regeneration or as a drug-delivery system. The incorporation of biologically active epitopes and/or the utilization of these scaffolds as stem cell carriers may further enhance their therapeutic efficacy.

Cell Therapy From Bench to Bedside Translation in CNS Neurorestoratology Era

Recent advances in cell biology, neural injury and repair, and the progress towards development of neurorestorative interventions are the basis for increased optimism. Based on the complexity of the processes of demyelination and remyelination, degeneration and regeneration, damage and repair, functional loss and recovery, it would be expected that effective therapeutic approaches will require a combination of strategies encompassing neuroplasticity, immunomodulation, neuroprotection, neurorepair, neuroreplacement, and neuromodulation. Cell-based restorative treatment has become a new trend, and increasing data worldwide have strongly proven that it has a pivotal therapeutic value in CNS disease. Moreover, functional neurorestoration has been achieved to a certain extent in the CNS clinically. Up to now, the cells successfully used in preclinical experiments and/or clinical trial/treatment include fetal/embryonic brain and spinal cord tissue, stem cells (embryonic stem cells, neural stem/progenitor cells, hematopoietic stem cells, adipose-derived adult stem/precursor cells, skin-derived precursor, induced pluripotent stem cells), glial cells (Schwann cells, oligodendrocyte, olfactory ensheathing cells, astrocytes, microglia, tanycytes), neuronal cells (various phenotypic neurons and Purkinje cells), mesenchymal stromal cells originating from bone marrow, umbilical cord, and umbilical cord blood, epithelial cells derived from the layer of retina and amnion, menstrual blood-derived stem cells, Sertoli cells, and active macrophages, etc. Proof-of-concept indicates that we have now entered a new era in neurorestoratology.

Transplantation of human marrow stromal cells and mono-nuclear bone marrow cells into the injured spinal cord: a comparative study

STUDY DESIGN

Two groups of 6 rats received dorsolateral funiculotomies followed by direct injection of bone marrow stromal cells (MSC) or mono-nuclear fraction of bone marrow (mnBM). Animals were killed at 4 or 21 days.

OBJECTIVE

Cellular transplantation is a promising treatment strategy for spinal cord injury (SCI); however, most cells need to be cultured before transplantation introducing burdensome steps for clinical application. Cells immediately available for transplantation, like mnBM, would be preferable.

SUMMARY OF BACKGROUND DATA

Previous studies have shown that MSC transplants promote protection and repair after SCI. MSC are attractive for transplantation because of easy isolation and availability of autologous sources. MSC are derived from whole bone marrow, purified and expanded in culture for a period of at least 2 weeks. Alternatively, mnBM could be used for transplantation. mnBM derived from bone marrow from through simple centrifugation can be reimplantated within hours; however, the presence of immune cells may be problematic.

METHODS

Cultured MSC or mnBM from human donors were acutely transplanted into SCI. After sacrifice, spinal cord sections were histologically analyzed for presence of graft-derived immune cells, host immune response, tissue sparing, glial scar formation, and grafting efficacy.

RESULTS

mnBM did not give rise to mature immune cells after transplantation into SCI, or evoke an increased host immune response or tissue loss compared to MSC-transplanted animals. In contrast, host macrophage/microglia response was increased early after MSC transplantation, perhaps due to exposure of cells to serum-containing media. The glial scar was less prominent after mnBM transplantation at day 4. At 21 days, differences had subsided and MSC and mnBM macrophage responses and effects on glial scarring were comparable. MSC and mnBM engraftment efficiencies were also similar.

CONCLUSION

The use of mnBM is a viable alternative to MSC for transplantation into SCI and may dramatically ease clinical translation.

Olfactory mucosal autografts and rehabilitation for chronic traumatic spinal cord injury

BACKGROUND/OBJECTIVE

Basic science advances in spinal cord injury (SCI) are leading to novel clinical approaches. The authors report a prospective, uncontrolled pilot study of the safety and outcomes of implanting olfactory mucosal autografts (OMA) in 20 patients with chronic, sensorimotor complete or motor complete SCI.

METHODS

Seven paraplegic and 13 tetraplegic subjects (17 men and 3 women; 19-37 years old) who sustained a traumatic SCI 18 to 189 months previously (mean = 49 months) were enrolled. Preoperative rehabilitation that emphasized lower extremity stepping using either overground walking training or a robotic weight-supported treadmill training was provided for 25 to 39 hours per week for a median of 4 months at 3 sites. No change in ASIA Impairment Scale (AIS) motor scores for the lower extremities or AIS grades of completeness was found. OMAs were transplanted into 1.3- to 4-cm lesions at C4-T12 neurological levels after partial scar removal. Therapy was continued postoperatively. Preoperative and postoperative assessments included AIS scores and classification, electromyography (EMG) of attempted voluntary contractions, somatosensory evoked potentials (SSEP), urodynamic studies with sphincter EMG, spinal cord magnetic resonance imaging (MRI), and otolaryngology and psychology evaluations. The Functional Independence Measure (FIM) and Walking Index for Spinal Cord Injury (WISCI) were obtained in 13 patients.

RESULTS

All patients survived and recovered olfaction. One patient was rehospitalized for aseptic meningitis. Minor adverse events occurred in 4 others. The mean duration of follow-up was 27.7 months (range = 12-45 months). By MRI, the lesion site was filled in all patients with no neoplastic overgrowth or syringomyelia. AIS grades improved in 11 of 20 patients, 6 (A --> C), 3 (B --> C), and 2 (A --> B), and declined in 1 (B --> A). Improvements included new voluntary EMG responses (15 patients) and SSEPs (4 patients). Scores improved in the FIM and WISCI (13/13 tested), and urodynamic responses improved in 5 patients.

CONCLUSION

OMA is feasible, relatively safe, and possibly beneficial in people with chronic SCI when combined with postoperative rehabilitation. Future controlled trials may need to include a lengthy and intensive rehabilitation arm as a control.

Administration of autologous bone marrow stem cells into spinal cord injury patients via multiple routes is safe and improves their quality of life: comprehensive case studies

Presently, there is no cure or effective treatment for spinal cord injury (SCI). Studies in SCI patients have shown that for a treatment to be effective it must primarily improve their quality of life. Numerous studies have shown that stem cells represent an alternative treatment for various disorders and have shown promise in several disease/trauma states. For instance, the use of autologous CD34+ stem cells has been shown to ameliorate symptoms of several disorders such as leukemia, cardiomyopathy, diabetes, and several autoimmune diseases, including multiple sclerosis. For the first time, we report eight case studies of SCI (four acute, four chronic) with approximately 2 years of follow-up that were administered bone marrow stem cells (BMSCs) via multiple routes: directly into the spinal cord, directly into the spinal canal, and intravenous. Magnetic resonance imaging illustrated morphological changes in the spinal cord of some of the patients following BMSCs administration. Comprehensive evaluations demonstrate improvements in ASIA, Barthel (quality of life), Frankel, and Ashworth scoring. Moreover, in order to assess bladder function, we designed a simple numerical clinical scoring system that demonstrates significant changes in bladder function following BMSCs administration. To date, we have administration BMSCs into 52 patients with SCI and have had no tumor formations, no cases of infection or increased pain, and few instances of minor adverse events. These studies demonstrate that BMSCs administration via multiple routes is feasible, safe, and may improve the quality of life for patients living with SCI.

Effect of bone marrow-derived mononuclear cells on nerve regeneration in the transection model of the rat sciatic nerve

Bone marrow-derived stem cells enhance the rate of regeneration and clinical improvement in nerve injury, spinal cord injury and brain infarction. Recent experiments in rat spinal cord demyelination showed that remyelination was specific to intravenous delivery of the bone marrow-derived mononuclear cell (BM-MNC) fraction, although the specific role of this fraction in peripheral nerve regeneration has not been examined. Therefore we evaluated the role of BM-MNCs in peripheral nerve regeneration in the rat sciatic nerve transection model. After anesthesia, the right sciatic nerve of 20 adult-male Wistar rats was transected under an operating microscope. In the test group, the cut ends of the nerve were approximated with two epineural microsutures, the gap was filled with rat BM-MNCs and the approximated nerve ends were covered with fibrin glue. In the control group, the transected nerve ends were repaired with two epineural microsutures and fibrin sealant only. Histological assessment of the nerve was performed 30 days and 60 days after the operation and regenerative changes were compared between the two groups. The recovery after nerve anastamosis was far better in the test group at both 30 days and 60 days. There was a statistically significant difference in axonal regeneration, remyelination and myelin thickness at sites 5mm and 10mm from the site of repair of the nerve. Schwann cell proliferation and degenerative changes were more prevalent in the controls. This study demonstrates that local delivery of BM-MNCs (which can be isolated easily from bone marrow aspirates) into injured peripheral nerve increases the rate and degree of nerve regeneration. The present study highlights the role of BM-MNCs in peripheral nerve regeneration.

Protection and repair of the injured spinal cord: a review of completed, ongoing, and planned clinical trials for acute spinal cord injury

Over the past 2 decades, advances in understanding the pathophysiology of spinal cord injury (SCI) have stimulated the recent emergence of several therapeutic strategies that are being examined in Phase I/II clinical trials. Ten randomized controlled trials examining methylprednisolone sodium succinate, tirilizad mesylate, monosialotetrahexosylganglioside, thyrotropin releasing hormone, gacyclidine, naloxone, and nimodipine have been completed. Although the primary outcomes in these trials were laregely negative, a secondary analysis of the North American Spinal Cord Injury Study II demonstrated that when administered within 8 hours of injury, methylprednisolone sodium succinate was associated with modest clinical benefits, which need to be weighed against potential complications. Thyrotropin releasing hormone (Phase II trial) and monosialotetrahexosylganglioside (Phase II and III trials) also showed some promise, but we are unaware of plans for future trials with these agents. These studies have, however, yielded many insights into the conduct of clinical trials for SCI. Several current or planned clinical trials are exploring interventions such as early surgical decompression (Surgical Treatment of Acute Spinal Cord Injury Study) and electrical field stimulation, neuroprotective strategies such as riluzole and minocycline, the inactivation of myelin inhibition by blocking Nogo and Rho, and the transplantation of various cellular substrates into the injured cord. Unfortunately, some experimental and poorly characterized SCI therapies are being offered outside a formal investigational structure, which will yield findings of limited scientific value and risk harm to patients with SCI who are understandably desperate for any intervention that might improve their function. Taken together, recent advances suggest that optimism for patients and clinicians alike is justified, as there is real hope that several safe and effective therapies for SCI may become available over the next decade.

Stem cell applications and tissue engineering approaches in surgical practice

There has been an increasing interest in stem cell applications and tissue engineering approaches in surgical practice to deal with damaged or lost tissue. Although there have been developments in almost all surgical disciplines, the greatest advances are being made in orthopaedics, especially in bone repair. Significant hurdles however remain to be overcome before tissue engineering becomes more routinely used in surgical practice.