Jason J. Lamanna

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.

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.

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.

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 cords 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.

Ferumoxytol Labeling of Human Neural Progenitor Cells for Diagnostic Cellular Tracking in the Porcine Spinal Cord With Magnetic Resonance Imaging

We report on the diagnostic capability of magnetic resonance imaging (MRI)‐based tracking of ferumoxytol‐labeled human neural progenitor cells (hNPCs) transplanted into the porcine spinal cord. hNPCs prelabeled with two doses of ferumoxytol nanoparticles (hNPC‐FLow and hNPC‐FHigh) were injected into the ventral horn of the spinal cord in healthy minipigs. Ferumoxytol‐labeled grafts were tracked in vivo up to 105 days after transplantation with MRI. Injection accuracy was assessed in vivo at day 14 and was predictive of “on” or “off” target cell graft location assessed by histology. No difference in long‐term cell survival, assessed by quantitative stereology, was observed among hNPC‐FLow, hNPC‐FHigh, or control grafts. Histological iron colocalized with MRI signal and engrafted human nuclei. Furthermore, the ferumoxytol‐labeled cells retained nanoparticles and function in vivo. This approach represents an important leap forward toward facilitating translation of cell‐tracking technologies to clinical trials by providing a method of assessing transplantation accuracy, delivered dose, and potentially cell survival. Stem Cells Translational Medicine 2017;6:139–150

Association of Overlapping Surgery With Patient Outcomes in a Large Series of Neurosurgical Cases

Importance Overlapping surgery (OS) is common. However, there is a dearth of evidence to support or refute the safety of this practice. Objective To determine whether OS is associated with worsened morbidity and mortality in a large series of neurosurgical cases. Design, Setting, and Participants A retrospective cohort study was completed for patients who underwent neurosurgical procedures at Emory University Hospital, a large academic referral hospital, between January 1, 2014, and December 31, 2015. Patients were operated on for pathologies across the spectrum of neurosurgical disorders. Propensity score weighting and logistic regression models were executed to compare outcomes for patients who received nonoverlapping surgery and OS. Investigators were blinded to study cohorts during data collection and analysis. Main Outcomes and Measures The primary outcome measures were 90-day postoperative mortality, morbidity, and functional status. Results In this cohort of 2275 patients who underwent neurosurgery, 1259 (55.3%) were female, and the mean (SD) age was 52.1 (16.4) years. A total of 972 surgeries (42.7%) were nonoverlapping while 1303 (57.3%) were overlapping. The distribution of American Society of Anesthesiologists score was similar between nonoverlapping surgery and OS cohorts. Median surgical times were significantly longer for patients in the OS cohort vs the nonoverlapping surgery cohort (in-room time, 219 vs 188 minutes; skin-to-skin time, 141 vs 113 minutes; both P < .001). Overlapping surgery was more frequently elective (93% vs 87%; P < .001). Regression analysis failed to demonstrate an association between OS and complications, such as mortality, morbidity, or worsened functional status. Measures of baseline severity of illness, such as admission to the intensive care unit and increased length of stay, were associated with mortality (intensive care unit: odds ratio [OR], 25.5; 95% CI, 6.22-104.67; length of stay: OR, 1.03; 95% CI, 1.00-1.05), morbidity (intensive care unit: OR, 1.85; 95% CI, 1.43-2.40; length of stay: OR, 1.06; 95% CI, 1.04-1.08), and unfavorable functional status (length of stay: OR, 1.03; 95% CI, 1.02-1.05). Conclusions and Relevance These data suggest that OS can be safely performed if appropriate precautions and patient selection are followed. Data such as these will help determine health care policy to maximize patient safety.

177 Pre-clinical Validation of Superparamagnetic Iron Oxide Nanoparticle-Labeled Neural Stem Cells for In Vivo Tracking and Post-Mortem Identification in the Spinal Cord

Tracking and Post-Mortem Identification in the Spinal Cord Jason J Lamanna BS; Eleanor M Donnelly; John N Oshinski; Nicholas M. Boulis MD; Thais Federici PhD Department of Neurosurgery, Emory University School of Medicine, Atlanta, GA Department of Biomedical Engineering, Emory University School of Medicine and Georgia Institute of Technology, Atlanta, GA Regenerative Medicine Institute, Cedars-Sinai Medical Center, Los Angeles, CA

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.

Spinal Cord Cellular Therapeutics Delivery: Device Design Considerations

Cell-based therapeutics are being increasingly trialed in both preclinical and clinical contexts for the treatment of multiple forms of intrinsic spinal cord pathology with either neuroprotective or neurorestorative intent. This therapeutic paradigm is being explored for the treatment of neurodegenerative (e.g., amyotrophic lateral sclerosis (ALS), spinal muscular atrophy (SMA)) and traumatic (e.g., spinal cord injury) indications. Cell-based therapies may also be considered for alternative indications such as multiple sclerosis and intramedullary neoplasms. Multiple delivery approaches may be considered to deliver a cellular therapy to the spinal cord. Preclinical and clinical studies have explored intravascular, intrathecal (e.g., subarachnoid), and intraparenchymal delivery approaches. In this chapter, we briefly describe the different cell delivery approaches and will primarily focus on the technical considerations encountered in the development of an intraparenchymal microinjection approach. An emphasis will be placed on areas of interest that continue to be investigated. The chapter concludes with an introduction of technologies that may augment next generation cell delivery approaches.

Peripheral blood detection of systemic graft-specific xeno-antibodies following transplantation of human neural progenitor cells into the porcine spinal cord

Extensive pre-clinical and clinical studies have searched for therapeutic efficacy of cell-based therapeutics in diseases of the Central Nervous System (CNS) with no other viable options. Allogeneic cells represent the primary source of these therapies and immunosuppressive regimens have been empirically employed based on experience with solid organ transplantation, attempting to avoid immune mediated graft rejection. In this study, we aimed to 1) characterize the host immune response to stem cells transplanted into the CNS and 2) develop a non-invasive method for detecting immune response to transplanted cell grafts. Human neural progenitor cells were transplanted into the spinal cord of 10 Göttingen minipigs, of which 5 received no immunosuppression and 5 received Tacrolimus. Peripheral blood samples were collected longitudinally for flow cytometry cross match studies. Necropsy was performed at day 21 and spinal cord tissue analysis. We observed a transient increase in xeno-reactive antibodies was detected on post-operative day 7 and 14 in pigs that did not receive immunosuppression. This response was not detected in pigs that received Tacrolimus immunosuppression. No difference in graft survival was observed between the groups. Infiltration of numerous immune mediators including granulocytes, T lymphocytes, and activated microglia, and complement deposition were detected. In summary, a systemic immunologic response to stem cell grafts was detected for two weeks after transplantation using peripheral blood. This could be used as a non-invasive biomarker by investigators for detection of immunologic rejection. However, the absence of a detectable response in peripheral blood does not rule out a parenchymal immune response.