REGENERATIVE THERAPY IN SPINAL CORD INJURIES: TRANSPLANT OF OLFACTORY ENHANCED GLIA, STEM CELLS AND OVEREXPRESSING SCHWANN CELLS G. Solcan 1., M. Musteaţă1, S. Iencean2   University of Agricultural Sciences and Veterinary Medicine, Faculty of Veterinary Medicine, Iasi, Romania, 8 M. Sadoveanu Alley, gsolcan@uaiasi.ro Nerosurgery Hospital “N. Oblu” Iasi

Introduction In veterinary clinics acute SCI type I IVDD, vertebral fractures and luxation, vascular disease (e.g. fibrocartilaginous embolism (FCE) and haemorrhage), cervical stenotic myelopathy and congenital malformation causing instability.  chronic diseases, such as neoplasia, discospondylitis and inflammatory or infectious spinal cord disease. Acute onset of SC dysfunction = a combination of one or more events including concussion, compression, ischemia, or laceration of the spinal cord.

Patophysiology

Strategy following SC injury 1. Neuroprotection: Diminution of the secondary damage 2.Neurorestauration: Remyelination, conduction 3. Neuroregeneration/Plasticity Antagonization of inhibitoy farctors Axonal growth factors (neurotrophyic) 4. Axonal guidance towards site of deafferation (specific regeneration) 5. Neurorectonstruction: Cell and tissue transplantation

Considerations for developing cell therapy for spinal cord regeneration To successfully treat SCI by promoting functional recovery, -cellular therapies must integrate into the injury site and restore the lost neuronal circuitry or promote plasticity of the spared neurons. For this goal, cellular therapies should be designed considering both the obstacles posed by the injury site as well as sourcing and reproducibility issues associated with different cell culture systems.

Obstacles to regeneration presented by the injured spinal cord - Cavity formation the initial injury + necrosis loss of grey and white matter = fluid filled cavity expand = additional cell death and increased loss of function physical barrier to spontaneous regeneration. bridge the lesion and restore signaling in the SC. factors that promote regeneration of the damaged axons into the cavity while also providing the trophic support necessary for cell migration. reduction of the cavity size = increase in functional recovery

Obstacles to regeneration presented by the injured spinal cord – Glial scar Transplanted cells = counterbalance to the inhibitory effects of the glial scar Secretion of the extracellular matrix and cytokines that promote cell migration Other therapy ± cell therapy molecules that prevent CSPG synthesis chondroitinases which degrade the CSPGs in vivo Migration of macrophages, oligodendrocyte precursors, and meningeal cells glial scar = predominantly reactive astrocyte inhibitory molecules into their extracellular matrix (CSPGs) inhibit axonal regeneration in 3D settings

Obstacles to regeneration presented by the injured spinal cord – Myelin based inhibitors Strategies Sialidase Tenascin-R genetic manipulation and antibodies damaged oligodendrocytes release myelin based inhibitors Nogo, MAG, Omgp, tenascin

Study and therapy in SC injury Cell type used Embrionic cell stem Mouse Human Neural cell stem Bone marrow stromal cell Mature cells Schwan OEG Fibroblasts Species consideration Invertebrates Small mammals Rats Mice Large mammals Cats Dogs Pigs Primates Contusions model Transection model

Cells Sources Transplantable cells can be obtained from : - the patient (autologous) - genetically different individuals, embryos, or umbilical cords (allogeneic) - different species (xenogeneic)   The undifferentiated nature of embryonic and umbilical cells minimizes immunological rejection.

Site of Transplantation Donor cells are transplanted in the spinal cord cerebro-spinal fluid intravenously intramuscularly

Surgical practice in spinal cord injury The surgical procedure consist of - remove of spinal cord scar - implanting of bone – marrow tissue into the spinal cord injury site. The bone-marrow tissue transplantation procedure has no complications. Scar reduction make the post – injury scar more permeable to neuronal axons attempting to regrow through the injury site.

Bone-marrow derived stem cells Dr. Tarcisio Barros (Sao Paulo) have infused bone-marrow-derived stem cells into the spinal artery closest to the injury site   Dr. Andrey Bryukhovetskiy (Moscow) has transplanted both embryonic / fetal stem cells and autologous adult stem cells Dr. K-S Kang (Seoul) injected stems cells isolated from umbilical cord blood into the injury area Dr. Yoon Ha (South Korea) has transplanted bone-marrow cells into the injury site of patients with acute SCI Dr. Eva Sykova (Prague ) have harvested autologous, bone-marrow stem cells from the iliac bone and re-introduced intravenously Dr. Yongfu Zhang (China) have transplanted autologous bone-marrow stem cells into patients with both acute and chronic SCI Bone-marrow derived stem cells

Olfactory Tissue and Cell Transplantation Dr. Carlos Lima (Lisbon) implant whole olfactory tissue from the patient back into the injury site   Dr. Hongyun Huang (Beijing) transplants OECs isolated from fetal olfactory bulbs Dr. Alan MacKay-Sim (Australia) has implanted autologous OECs back into the patient’s injured cord Dr. Tiansheng Sun (Beijing) have transplanted OECs into patients with SCI

OTHER CELL TRANSPLANTATION Dr. Fernando Ramirez (Mexico) has transplanted blue-shark, embryonic neuronal cells (xenogeneic transplantation)   The Diacrin Corporation (USA) sponsored another xenotransplantation clinical trial. Dr John McDonald (Missouri) and Dr Darryl DiRisio (Albany) injected immature fetal pig, myelin cells into the cord surrounding the injury site Dr. Hui Zhu have transplanted fetal Schwann cells

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