Targeted spinal cord therapeutics delivery: stabilized platform and microelectrode recording guidance validation

Prussian blue nanocubes as a multimodal contrast agent for image-guided stem cell therapy of the spinal cord

Translation of stem cell therapies to treat injuries and diseases of the spinal cord is hindered by lack of real-time monitoring techniques to guide regenerative therapies intra- and postoperatively. Thus, we developed an ultrasound (US), photoacoustic (PA), and magnetic resonance (MR) imaging approach augmented with Prussian blue nanocubes (PBNCs) to guide stem cell injections intraoperatively and monitor stem cell therapies in the spinal cord postoperatively. Per the clinical procedure, a multi-level laminectomy was performed in rats ex vivo, and PBNC-labeled stem cells were injected directly into the spinal cord while US/PA images were acquired. US/PA/MR images were also acquired post-surgery. Several features of the imaging approach were demonstrated including detection of low stem cell concentrations, real-time needle guidance and feedback on stem cell delivery, and good agreement between US/PA/MR images. These benefits span intra- and postoperative environments to support future development of this imaging tool.

Targeted intraspinal injections to assess therapies in rodent models of neurological disorders

Despite decades of research, pharmacological therapies for spinal cord motor pathologies are limited. Alternatives using macromolecular, viral, or cell-based therapies show early promise. However, introducing these substances into the spinal cord, past the blood-brain barrier, without causing injury is challenging. We describe a technique for intraspinal injection targeting the lumbar ventral horn in rodents. This technique preserves motor performance and has a proven track record of translation into phase 1 and 2 clinical trials in amyotrophic lateral sclerosis (ALS) patients. The procedure, in brief, involves exposure of the thoracolumbar spine and dissection of paraspinous muscles over the target vertebrae. Following laminectomy, the spine is affixed to a stereotactic frame, permitting precise and reproducible injection throughout the lumbar spine. We have used this protocol to inject various stem cell types, primarily human spinal stem cells (HSSCs); however, the injection is adaptable to any candidate therapeutic cell, virus, or macromolecule product. In addition to a detailed procedure, we provide stereotactic coordinates that assist in targeting of the lumbar spine and instructional videos. The protocol takes ~2 h per animal.

Photoacoustic Image-Guided Delivery of Plasmonic-Nanoparticle-Labeled Mesenchymal Stem Cells to the Spinal Cord

Regenerative therapies using stem cells have great potential for treating neurodegenerative diseases and traumatic injuries in the spinal cord. In spite of significant research efforts, many therapies fail at the clinical phase. As stem cell technologies advance toward clinical use, there is a need for a minimally invasive, safe, affordable, and real-time imaging technique that allows for the accurate and safe monitoring of stem cell delivery in the operating room. In this work, we present a combined ultrasound and photoacoustic imaging tool to provide image-guided needle placement and monitoring of nanoparticle-labeled stem cell delivery into the spinal cord. We successfully tagged stem cells using gold nanospheres and provided image-guided delivery of stem cells into the spinal cord in real-time, detecting as few as 1000 cells. Ultrasound and photoacoustic imaging was used to guide needle placement for direct stem cell injection to minimize the risk of needle shear and accidental injury and to improve therapeutic outcomes with accurate, localized stem cell delivery. Following injections of various volumes of cells, three-dimensional ultrasound and photoacoustic images allowed the visualization of stem cell distribution along the spinal cord, showing the potential to monitor the migration of the cells in the future. The feasibility of quantitative imaging was also shown by correlating the total photoacoustic signal over the imaging volume to the volume of cells injected. Overall, the presented method may allow clinicians to utilize imaged-guided delivery for more accurate and safer stem cell delivery to the spinal cord.

AAV gene delivery to the spinal cord: serotypes, methods, candidate diseases, and clinical trials

INTRODUCTION

Adeno-associated viral (AAV) vector-mediated gene delivery to the spinal cord has finally entered the pathway towards regulatory approval. Phase 1 clinical trials using AAV gene therapy for pediatric disorders - spinal muscular atrophy (SMA) and giant axonal neuropathy (GAN) - are now underway.

AREAS COVERED

This review addresses the latest progress in the field of AAV gene delivery to the spinal cord, particularly focusing on the most prominent AAV serotypes and delivery methodologies to the spinal cord. Candidate diseases and scaling up experiments in large animals are also discussed.

EXPERT OPINION

Intravenous (IV) and intrathecal (IT) deliveries seem to undoubtedly be the preferred routes of administration for diffuse spinal cord delivery of therapeutic AAV vectors that can cross the blood-brain barrier (BBB) and correct inherited genetic disorders. Conversely, intraparenchymal delivery is still an undervalued but very viable approach for segmental therapy in afflictions such as ALS or Pompe Disease as a means to prevent respiratory dysfunction.

Magnetic Resonance Imaging-Guided Transplantation of Neural Stem Cells into the Porcine Spinal Cord

BACKGROUND

Cell-based therapies are a promising treatment option for traumatic, tumorigenic and degenerative diseases of the spinal cord. Transplantation into the spinal cord is achieved with intravascular, intrathecal, or direct intraparenchymal injection. The current standard for direct injection is limited by surgical invasiveness, difficulty in reinjection, and the inability to directly target anatomical or pathological landmarks. The objective of this study was to present the proof of principle for minimally invasive, percutaneous transplantation of stem cells into the spinal cord parenchyma of live minipigs under MR guidance.

METHODS

An MR-compatible spine injection platform was developed to work with the ClearPoint SmartFrame system (MRI Interventions Inc.). The system was attached to the spine of 2 live minipigs, a percutaneous injection cannula was advanced into the spinal cord under MR guidance, and cells were delivered to the cord.

RESULTS

A graft of 2.5 × 106 human (n = 1) or porcine (n = 1) neural stem cells labeled with ferumoxytol nanoparticles was transplanted into the ventral horn of the spinal cord with MR guidance in 2 animals. Graft delivery was visualized with postprocedure MRI, and characteristic iron precipitates were identified in the spinal cord by Prussian blue histochemistry. Grafted stem cells were observed in the spinal cord of the pig injected with porcine neural stem cells. No postoperative morbidity was observed in either animal.

CONCLUSION

This report supports the proof of principle for transplantation and visualization of pharmacological or biological agents into the spinal cord of a large animal under the guidance of MRI.

Transplantation of spinal cord-derived neural stem cells for ALS: Analysis of phase 1 and 2 trials

OBJECTIVE

To test the safety of spinal cord transplantation of human stem cells in patients with amyotrophic lateral sclerosis (ALS) with escalating doses and expansion of the trial to multiple clinical centers.

METHODS

This open-label trial included 15 participants at 3 academic centers divided into 5 treatment groups receiving increasing doses of stem cells by increasing numbers of cells/injection and increasing numbers of injections. All participants received bilateral injections into the cervical spinal cord (C3-C5). The final group received injections into both the lumbar (L2-L4) and cervical cord through 2 separate surgical procedures. Participants were assessed for adverse events and progression of disease, as measured by the ALS Functional Rating Scale-Revised, forced vital capacity, and quantitative measures of strength. Statistical analysis focused on the slopes of decline of these phase 2 trial participants alone or in combination with the phase 1 participants (previously reported), comparing these groups to 3 separate historical control groups.

RESULTS

Adverse events were mostly related to transient pain associated with surgery and to side effects of immunosuppressant medications. There was one incident of acute postoperative deterioration in neurologic function and another incident of a central pain syndrome. We could not discern differences in surgical outcomes between surgeons. Comparisons of the slopes of decline with the 3 separate historical control groups showed no differences in mean rates of progression.

CONCLUSIONS

Intraspinal transplantation of human spinal cord-derived neural stem cells can be safely accomplished at high doses, including successive lumbar and cervical procedures. The procedure can be expanded safely to multiple surgical centers.

CLASSIFICATION OF EVIDENCE

This study provides Class IV evidence that for patients with ALS, spinal cord transplantation of human stem cells can be safely accomplished and does not accelerate the progression of the disease. This study lacks the precision to exclude important benefit or safety issues.

Preclinical Validation of Multilevel Intraparenchymal Stem Cell Therapy in the Porcine Spinal Cord

BACKGROUND:

Although multiple clinical trials are currently testing different stem cell therapies as treatment alternatives for many neurodegenerative diseases and spinal cord injury, the optimal injection parameters have not yet been defined.

OBJECTIVE:

To test the spinal cord's tolerance to increasing volumes and numbers of stem cell injections in the pig.

METHODS:

Twenty-seven female Göttingen minipigs received human neural progenitor cell injections using a stereotactic platform device. Cell transplantation in groups 1 to 5 (5–7 pigs in each) was undertaken with the intent of assessing the safety of an injection volume escalation (10, 25, and 50 µL) and an injection number escalation (20, 30, and 40 injections). Motor function and general morbidity were assessed for 21 days. Full necropsy was performed; spinal cords were analyzed for graft survival and microscopic tissue damage.

RESULTS:

No mortality or permanent surgical complications were observed during the 21-day study period. All animals returned to preoperative baseline within 14 days, showing complete motor function recovery. The histological analysis showed that there was no significant decrease in neuronal density between groups, and cell engraftment ranged from 12% to 31% depending on the injection paradigm. However, tissue damage was identified when injecting large volumes into the spinal cord (50 μL).

CONCLUSION:

This series supports the functional safety of various injection volumes and numbers in the spinal cord and gives critical insight into important safety thresholds. These results are relevant to all translational programs delivering cell therapeutics to the spinal cord.

Human neural stem cell transplantation in ALS: initial results from a phase I trial

Background

We report the initial results from a phase I clinical trial for ALS. We transplanted GMP-grade, fetal human neural stem cells from natural in utero death (hNSCs) into the anterior horns of the spinal cord to test for the safety of both cells and neurosurgical procedures in these patients. The trial was approved by the Istituto Superiore di Sanità and the competent Ethics Committees and was monitored by an external Safety Board.

Methods

Six non-ambulatory patients were treated. Three of them received 3 unilateral hNSCs microinjections into the lumbar cord tract, while the remaining ones received bilateral (n = 3 + 3) microinjections. None manifested severe adverse events related to the treatment, even though nearly 5 times more cells were injected in the patients receiving bilateral implants and a much milder immune-suppression regimen was used as compared to previous trials.

Results

No increase of disease progression due to the treatment was observed for up to18 months after surgery. Rather, two patients showed a transitory improvement of the subscore ambulation on the ALS-FRS-R scale (from 1 to 2). A third patient showed improvement of the MRC score for tibialis anterior, which persisted for as long as 7 months. The latter and two additional patients refused PEG and invasive ventilation and died 8 months after surgery due to the progression of respiratory failure. The autopsies confirmed that this was related to the evolution of the disease.

Conclusions

We describe a safe cell therapy approach that will allow for the treatment of larger pools of patients for later-phase ALS clinical trials, while warranting good reproducibility. These can now be carried out under more standardized conditions, based on a more homogenous repertoire of clinical grade hNSCs. The use of brain tissue from natural miscarriages eliminates the ethical concerns that may arise from the use of fetal material.

Trial registration

EudraCT:2009-014484-39.

Concise review: Stem cell therapies for amyotrophic lateral sclerosis: recent advances and prospects for the future

Amyotrophic lateral sclerosis (ALS) is a lethal disease involving the loss of motor neurons. Although the mechanisms responsible for motor neuron degeneration in ALS remain elusive, the development of stem cell-based therapies for the treatment of ALS has gained widespread support. Here, we review the types of stem cells being considered for therapeutic applications in ALS, and emphasize recent preclinical advances that provide supportive rationale for clinical translation. We also discuss early trials from around the world translating cellular therapies to ALS patients, and offer important considerations for future clinical trial design. Although clinical translation is still in its infancy, and additional insight into the mechanisms underlying therapeutic efficacy and the establishment of long-term safety are required, these studies represent an important first step toward the development of effective cellular therapies for the treatment of ALS.

Intraspinal neural stem cell transplantation in amyotrophic lateral sclerosis: phase 1 trial outcomes

Objective

The US Food and Drug Administration–approved trial, “A Phase 1, Open-Label, First-in-Human, Feasibility and Safety Study of Human Spinal Cord-Derived Neural Stem Cell Transplantation for the Treatment of Amyotrophic Lateral Sclerosis, Protocol Number: NS2008-1,” is complete. Our overall objective was to assess the safety and feasibility of stem cell transplantation into lumbar and/or cervical spinal cord regions in amyotrophic lateral sclerosis (ALS) subjects.

Methods

Preliminary results have been reported on the initial trial cohort of 12 ALS subjects. Here, we describe the safety and functional outcome monitoring results for the final trial cohort, consisting of 6 ALS subjects receiving 5 unilateral cervical intraspinal neural stem cell injections. Three of these subjects previously received 10 total bilateral lumbar injections as part of the earlier trial cohort. All injections utilized a novel spinal-mounted stabilization and injection device to deliver 100,000 neural stem cells per injection, for a dosing range up to 1.5 million cells. Subject assessments included detailed pre- and postsurgical neurological outcome measures.

Results

The cervical injection procedure was well tolerated and disease progression did not accelerate in any subject, verifying the safety and feasibility of cervical and dual-targeting approaches. Analyses on outcome data revealed preliminary insight into potential windows of stem cell biological activity and identified clinical assessment measures that closely correlate with ALS Functional Rating Scale-Revised scores, a standard assessment for ALS clinical trials.

Interpretation

This is the first report of cervical and dual-targeted intraspinal transplantation of neural stem cells in ALS subjects. This approach is feasible and well-tolerated, supporting future trial phases examining therapeutic dosing and efficacy.

Cellular therapeutics delivery to the spinal cord: technical considerations for clinical application

Current literature demonstrates the efficacy of cell-based therapeutics in small animal models of varied spinal cord diseases. However, logistic challenges remain towards development of an optimized delivery approach to the human spinal cord. Clinical trials utilize a variety of methods to achieve this aim. In this article, the authors review currently employed delivery methods, compare the merits of alternate delivery paradigms, introduce their implementation in completed and ongoing clinical trials, and discuss promising near-term advances in image-guided delivery and in vivo graft tracking.

Gene and protein therapies utilizing VEGF for ALS

Amyotrophic lateral sclerosis (ALS) is a progressive neurodegenerative disease that is usually fatal within 2-5years. Unfortunately, the only treatment currently available is riluzole, which has a limited efficacy. As a redress, there is an expanding literature focusing on other potential treatments. One such potential treatment option utilizes the vascular endothelial growth factor (VEGF) family, which includes factors that are primarily associated with angiogenesis but are now increasingly recognized to have neurotrophic effects. Reduced expression of a member of this family, VEGF-A, in mice results in neurodegeneration similar to that of ALS, while treatment of animal models of ALS with either VEGF-A gene therapy or VEGF-A protein has yielded positive therapeutic outcomes. These basic research findings raise the potential for a VEGF therapy to be translated to the clinic for the treatment of ALS. This review covers the VEGF family, its receptors and neurotrophic effects as well as VEGF therapy in animal models of ALS and advances towards clinical trials.

Intraspinal stem cell transplantation in amyotrophic lateral sclerosis: a phase I safety trial, technical note, and lumbar safety outcomes

BACKGROUND

No United States-based clinical trials have attempted delivery of biological therapies directly to the spinal cord for treatment of amyotrophic lateral sclerosis (ALS) because of the lack of a meaningful US Food and Drug Administration-authorized cell candidate and a validated delivery approach.

OBJECTIVE

To assess safety of delivery of a neural stem cell-based treatment into the upper lumbar segments of the ALS spinal cord in the first US Food and Drug Administration-authorized phase I trial.

METHODS

Each microinjection series comprised 5 injections (10 μL/injection) separated by 4 mm. Each injection deposited 100,000 neural stem cells derived from a fetal spinal cord. Twelve patients were treated with either unilateral or bilateral injections. Group A, nonambulatory patients, underwent unilateral (n = 3) or bilateral (n = 3) lumbar microinjections. Groups B and C were ambulatory (n = 3 each) and, respectively, received unilateral or bilateral injections. Patients are followed clinically and radiologically to assess potential toxicity of the procedure.

RESULTS

Twelve patients have received a transplant. There was one instance of transient intraoperative somatosensory-evoked potentials depression. In the immediate postoperative period, there was 1 episode of urinary retention requiring Foley catheter reinsertion. By discharge, none had a documented motor function decrement. Two patients required readmission and reoperation for cerebrospinal fluid leak or suprafascial wound dehiscence (n = 1 each). Two deaths occurred at 8 and 13 months postsurgery; neither was related to the surgical transplant.

CONCLUSION

Our experience in 12 patients supports the procedural safety of unilateral and bilateral intraspinal lumbar microinjection. Completion of this phase I safety trial is planned by proceeding to cervical and combined cervical + lumbar microinjections in ALS patients.

Surgical technique for spinal cord delivery of therapies: demonstration of procedure in gottingen minipigs

This is a compact visual description of a combination of surgical technique and device for the delivery of (gene and cell) therapies into the spinal cord. While the technique is demonstrated in the animal, the procedure is FDA-approved and currently being used for stem cell transplantation into the spinal cords of patients with ALS. While the FDA has recognized proof-of-principle data on therapeutic efficacy in highly characterized rodent models, the use of large animals is considered critical for validating the combination of a surgical procedure, a device, and the safety of a final therapy for human use. The size, anatomy, and general vulnerability of the spine and spinal cord of the swine are recognized to better model the human. Moreover, the surgical process of exposing and manipulating the spinal cord as well as closing the wound in the pig is virtually indistinguishable from the human. We believe that the healthy pig model represents a critical first step in the study of procedural safety.

Lumbar intraspinal injection of neural stem cells in patients with amyotrophic lateral sclerosis: results of a phase I trial in 12 patients

Advances in stem cell biology have generated intense interest in the prospect of transplanting stem cells into the nervous system for the treatment of neurodegenerative diseases. Here, we report the results of an ongoing phase I trial of intraspinal injections of fetal-derived neural stems cells in patients with amyotrophic lateral sclerosis (ALS). This is a first-in-human clinical trial with the goal of assessing the safety and tolerability of the surgical procedure, the introduction of stem cells into the spinal cord, and the use of immunosuppressant drugs in this patient population. Twelve patients received either five unilateral or five bilateral (10 total) injections into the lumbar spinal cord at a dose of 100,000 cells per injection. All patients tolerated the treatment without any long-term complications related to either the surgical procedure or the implantation of stem cells. Clinical assessments ranging from 6 to 18 months after transplantation demonstrated no evidence of acceleration of disease progression due to the intervention. One patient has shown improvement in his clinical status, although these data must be interpreted with caution since this trial was neither designed nor powered to measure treatment efficacy. These results allow us to report success in achieving the phase I goal of demonstrating safety of this therapeutic approach. Based on these positive results, we can now advance this trial by testing intraspinal injections into the cervical spinal cord, with the goal of protecting motor neuron pools affecting respiratory function, which may prolong life for patients with ALS.

Translating cellular therapies from bench to bedside for amyotrophic lateral sclerosis

The last decade has witnessed an increasing number of biologic (e.g., cell- or viral vector-based) therapeutics supported by preclinical efficacy data for the treatment of afflictions to the CNS. While some international investigators have undertaken preliminary clinical safety studies, published literature indicate varying degrees of rigor with respect to study design and technical approach. To our knowledge, ours is the first group to have systematically generated preclinical validation data for a delivery approach and translated this into a Phase I trial attempting to covalidate the safety of a direct, targeted delivery approach, as well as a cell-based therapeutic. This article discusses the rationale for cell-based therapy in amyotrophic lateral sclerosis and several of the unique considerations encountered during this process.

Update on gene and stem cell therapy approaches for spinal muscular atrophy

INTRODUCTION

Spinal muscular atrophy (SMA) is the leading genetic cause of pediatric death to which at present there is no effective therapeutic. The genetic defect is well characterized as a mutation in exon 7 of the survival of motor neuron (SMN) gene. The current gene therapy approach focuses on two main methodologies, the replacement of SMN1 or augmentation of SMN2 readthrough. The most promising of the current work focuses on the delivery of SMN via AAV9 vectors via intravenous delivery.

AREAS COVERED

In the review the authors examine the current research in the field of stem cell and gene therapy approaches for SMA. Also focusing on delivery methods, timing of administration and general caveats that must be considered with translational work for SMA.

EXPERT OPINION

Gene therapy currently offers the most promising avenue of research for a successful therapeutic for SMA. There are many important practical and ethical considerations which must be carefully considered when dealing with clinical trial in infants such as the invasiveness of the surgery, the correct patient cohort and the potential risks.

Stem cell therapy for the spinal cord

Injury and disease of the spinal cord are generally met with a poor prognosis. This poor prognosis is due not only to the characteristics of the diseases but also to our poor ability to deliver therapeutics to the spinal cord. The spinal cord is extremely sensitive to direct manipulation, and delivery of therapeutics has proven a challenge for both scientists and physicians. Recent advances in stem cell technologies have opened up a new avenue for the treatment of spinal cord disease and injury. Stem cells have proven beneficial in rodent models of spinal cord disease and injury. In these animal models, stem cells have been shown to produce their effect by the dual action of cell replacement and the trophic support of the factors secreted by these cells. In this review we look at the main clinical trials involving stem cell transplant into the spinal cord, focusing on motor neuron diseases and spinal cord injury. We will also discuss the major hurdles in optimizing stem cell delivery methods into the spinal cord. We shall examine current techniques such as functional magnetic resonance imaging guidance and cell labeling and will look at the current research striving to improve these techniques. With all caveats and future research taken into account, this is a very exciting time for stem cell transplant into the spinal cord. We are only beginning to realize the huge potential of stem cells in a central nervous system setting to provide cell replacement and trophic support. Many more trials will need to be undertaken before we can fully exploit the attributes of stem cells.

Platform and cannula design improvements for spinal cord therapeutics delivery

BACKGROUND

Only recently have data been published attempting to validate a technology and technique suitable for targeted delivery of biological payloads to the human spinal cord.

OBJECTIVE

To characterize the development and evolution of a spine-stabilized microinjection platform as a vehicle for biologics delivery to the cervical and thoracolumbar spine on the basis of preclinical experience in both non-Good Laboratory Practice (GLP) experimental series and GLP studies.

METHODS

Our laboratory completed > 100 cervical and lumbar porcine microinjection procedures between July 2004 and June 2010. This included both non-GLP- and GLP-adherent survival series to validate the safety and accuracy achievable with intraspinal microinjection. During this time, 3 different microinjection platforms, injection stages, and cannula designs were tested.

RESULTS

Repetitive technological improvements reduced incision length, decreased procedural complexity, and simplified ventral horn targeting and accuracy. These changes reduced procedural invasiveness and the likelihood of neurological morbidity while improving targeting accuracy. In part as a result of these technological improvements and procedural modifications, we have safely progressed from single unilateral microinjections to multiple bilateral injections without long-term neurological sequelae.

CONCLUSION

Technological and procedural refinements have significantly enhanced the capabilities of intraspinal microinjection-based biologics delivery. Reductions in procedural invasiveness and the capability to deliver sequential biological payloads effectively have broadened the flexibility of intraspinal microinjection to a widened array of intrinsic spinal cord pathologies. These advances have laid the groundwork for clinical translation of spinal cord microinjections.

Stem cell technology for the study and treatment of motor neuron diseases

Amyotrophic lateral sclerosis and spinal muscular atrophy are devastating neurodegenerative diseases that lead to the specific loss of motor neurons. Recently, stem cell technologies have been developed for the investigation and treatment of both diseases. Here we discuss the different stem cells currently being studied for mechanistic discovery and therapeutic development, including embryonic, adult and induced pluripotent stem cells. We also present supporting evidence for the utilization of stem cell technology in the treatment of amyotrophic lateral sclerosis and spinal muscular atrophy, and describe key issues that must be considered for the transition of stem cell therapies for motor neuron diseases from bench to bedside. Finally, we discuss the first-in-human Phase I trial currently underway examining the safety and feasibility of intraspinal stem cell injections in amyotrophic lateral sclerosis patients as a foundation for translating stem cell therapies for various neurological diseases.

Cervical multilevel intraspinal stem cell therapy: assessment of surgical risks in Gottingen minipigs

STUDY DESIGN

Assessment of long-term surgical risks from multiple intraspinal cell injections.

OBJECTIVE

To prove that multilevel-targeted cell injection to the spinal cord can be a feasible and safe procedure.

SUMMARY OF BACKGROUND DATA

Neural cell transplantation has been proposed as a treatment for a variety of neurologic disorders, including degenerative, ischemic, autoimmune, and traumatic etiologies. Among these diseases, the lack of effective treatment for amyotrophic lateral sclerosis has prompted the search for cell-based neuroprotection or motor neuron-replacement therapies.

METHODS

Fifteen female minipigs, divided into 3 experimental groups, underwent either 5 or 10 unilateral injections of neural stem cells or 10 vehicle injections into the C3-C5 segments of the spinal cord, using a device and technique developed for safe and accurate injection into the human spinal cord. All animals received intravenous Tacrolimus (0.025 mg/kg) BID during the course of the study. Sensory and motor functions as well as general morbidity were assessed for 28 days. Full necropsy was performed and spinal cords were analyzed for graft survival. This study was performed under Good Laboratory Practice conditions.

RESULTS

Neither mortality nor permanent surgical complications were observed within the 28-day study period. All animals returned to preoperative baseline showing full motor function recovery. Graft survival was demonstrated by immunohistochemistry.

CONCLUSION

Clinically acceptable neural progenitor survival, distribution, and density were achieved using the number of injections and surgical techniques specifically developed for this purpose.

Preclinical safety validation of a stabilized viral vector direct injection approach to the cervical spinal cord

The current lack of a validated intraspinal delivery approach precludes translation of promising cell or viral-based therapeutics for treatment of varied spinal cord afflictions. We have developed a stabilized cervical microinjection platform with the intent of precise delivery to intraspinal sites of interest. Nine 30-40 kg female swine underwent coordinate-based microinjection AAV2-GFP at three injected volumes (10, 25, and 50 microL (n= 3/group)) and matched infusion rates (1.0, 2.5, and 5.0 microL/min) over a period (t= 10 minutes). Preliminary validation is provided by behavioral and targeting data demonstrating safe delivery of a viral vector carrying a fluorescent reporter gene to the cervical spinal cord ventral horn.

Cervical spinal cord therapeutics delivery: preclinical safety validation of a stabilized microinjection platform

OBJECTIVE

The current series represents a preclinical safety validation study for direct parenchymal microinjection of cellular grafts into the ventral horn of the porcine cervical spinal cord.

METHODS

Twenty-four 30- to 40-kg female Yorkshire farm pigs immunosuppressed with cyclosporine underwent a cervical laminectomy and ventral horn human neural progenitor cell injection. Cell transplantation in groups 1 to 3 (n = 6 pigs each) was undertaken with the intent of assessing the safety of varied injection volumes: 10, 25, and 50 microL injected at 1, 2.5, and 5 microL/min, respectively. Groups 4 and 5 (n = 3 pigs each) received prolonged immunosuppressant pretreatment in an attempt to demonstrate graft viability. The latter was undertaken in an alternate species (mini-pig versus Yorkshire pig).

RESULTS

Neurological morbidity was observed in 1 animal and was attributable to the presence of a resolving epidural hematoma noted at necropsy. Although instances of ventral horn targeting were achieved in all injection groups with a coordinate-based approach, opportunities exist for improvement in accuracy and precision. A relationship between injection volume and graft site cross-sectional area suggested limited reflux. Only animals from group 5 achieved graft survival at a survival end point (t = 1 week).

CONCLUSION

This series demonstrated the functional safety of targeted ventral horn microinjection despite evidence for graft site immune rejection. Improvements in graft delivery may be augmented with an adapter to improve control of the cannula entry angle, intraoperative imaging, or larger graft volumes. Finally, demonstration of long-term graft viability in future preclinical toxicity studies may require tailored immunosuppressive therapies, an allograft construct, or tailored choice of host species.

Mesenchymal stem cell transplantation in amyotrophic lateral sclerosis: A Phase I clinical trial

Amyotrophic Lateral Sclerosis (ALS) is a devastating incurable disease. Stem-cell-based therapies represent a new possible strategy for ALS clinical research. The objectives of this Phase 1 clinical study were to assess the feasibility and toxicity of mesenchymal stem cell transplantation and to test the impact of a cell therapy in ALS patients. The trial was approved and monitored by the National Institute of Health and by the Ethics Committees of all participating Institutions. Autologous MSCs were isolated from bone marrow, expanded in vitro and analyzed according to GMP conditions. Expanded MSCs were suspended in the autologous cerebrospinal fluid (CSF) and directly transplanted into the spinal cord at a high thoracic level with a surgical procedure. Ten ALS patients were enrolled and regularly monitored before and after transplantation by clinical, psychological, neuroradiological and neurophysiological assessments. There was no immediate or delayed transplant-related toxicity. Clinical, laboratory, and radiographic evaluations of the patients showed no serious transplant-related adverse events. Magnetic resonance images (MRI) showed no structural changes (including tumor formation) in either the brain or the spinal cord. However the lack of post mortem material prevents any definitive conclusion about the vitality of the MSCs after transplantation. In conclusion, this study confirms that MSC transplantation into the spinal cord of ALS patients is safe and that MSCs might have a clinical use for future ALS cell based clinical trials.

Intraspinal cord delivery of IGF-I mediated by adeno-associated virus 2 is neuroprotective in a rat model of familial ALS

BACKGROUND

Amyotrophic lateral sclerosis (ALS) is a devastating disease that is characterized by the progressive loss of motor neurons. Patients with ALS usually die from respiratory failure due to respiratory muscle paralysis. Consequently, therapies aimed at preserving segmental function of the respiratory motor neurons could extend life for these patients. Insulin-like growth factor-I (IGF-I) is known to be a potent survival factor for motor neurons. In this study we induced high levels of IGF-I expression in the cervical spinal cord of hSOD1(G93A) rats with intraspinal cord (ISC) injections of an adeno-associated virus serotype 2 vector (CERE-130). This approach reduced the extent of motor neuron loss in the treated segments of the spinal cord. However, a corresponding preservation of motor function was observed in male, but not female, hSOD1(G93A) rats. We conclude that ISC injection of CERE-130 has the potential to protect motor neurons and preserve neuromuscular function in ALS.