*S. NORI1, J.-E. AHLFORS2, M. KHAZAEI1, Y. LIU1, J. WANG1, T. FUEHRMANN3, M. M. PAKULSKA3, M. HETTIARATCHI3, P. POON3, M. S. SHOICHET3, M. G. FEHLINGS1,4;
1Div. of Genet. and Develop., Krembil Res. Inst., Toronto, ON, Canada; 2New World Labs., Laval, QC, Canada; 3Chem. Engin. and Applied Chem., 4Inst. of Med. Sci., Univ. of Toronto, Toronto, ON, Canada
Introduction: Treatment of chronic spinal cord injury (SCI) is challenging due to cellular loss, cystic cavity and the inhibitory influence of the glial scar. Previous research has shown that the combinatorial therapy of neural precursor cells (NPCs) and chondroitinase ABC (ChABC), which degrades chondroitin sulfate proteoglycans (CSPGs), promotes motor functional recovery after chronic SCI. However, the translational potential of NPCs is hindered by limited availability, immunologic complications and ethical concerns. To overcome these challenges, we have developed a novel approach to generate NPCs through direct reprogramming of somatic cells (drNPCs). We differentiate drNPCs into oligogenic cells (drNPC-pro-OPCs) and have demonstrated functional recovery after drNPC-pro-OPCs transplantation in subacute SCI. To improve cell integration in the chronic phase, a less invasive sustainable delivery system of ChABC via a methylcellulose (MC) hydrogel (MC-ChABC) was used. The purpose of this study is to determine the therapeutic potential of the combinatorial therapy of drNPC-pro-OPCs and MC-ChABC following chronic SCI.
Methods: Adult Rowett Nude rats received clip compression SCI at T7 level. At 6w after SCI, MC-ChABC, MC alone or artificial cerebrospinal fluid (aCSF) were injected intrathecally. At 7w after SCI, drNPC-pro-OPCs or aCSF were injected intraspinally. The following groups were studied: 1) MC-ChABC + drNPC-pro-OPCs (n=12), 2) MC-ChABC + aCSF (n=5), 3) MC + drNPC-pro-OPCs (n=11), 4) MC + aCSF (n=5), 5) aCSF + drNPC-pro-OPCs (n=8), 6) aCSF + aCSF (control group, n=12). During the 19-week post SCI period, functional assessments including BBB, CatWalk system and von Frey test were performed.
Results: Grafted drNPC-pro-OPCs survived within the injured spinal cord and differentiated principally into oligodendrocytes at 19 weeks after SCI without tumor formation. Expression of CSPGs was successfully reduced in MC-ChABC-treated groups. Cell survival rates were higher in the drNPC-pro-OPCs and MC-ChABC combinatorial therapy group than the other groups. Motor function in the combinatorial therapy group was significantly improved as measured by BBB scores and the CatWalk system compared to the control group. Sensory function assessed by von Frey test demonstrated no significant difference among the groups.
Conclusion: The present study demonstrates that the MC-ChABC and drNPC-pro-OPCs mediated strategy induces functionally significant repair and regeneration of the chronic injured spinal cord. These findings may facilitate the clinical application of the combinatorial therapy for patients suffering from chronic SCI.
S. Nori: None. J. Ahlfors: A. Employment/Salary (full or part-time):; New World Laboratories, Fortuna Fix. M. Khazaei: None. Y. Liu: None. J. Wang: None. T. Fuehrmann: None. M.M. Pakulska: None. M. Hettiaratchi: None. P. Poon: None. M.S. Shoichet: None. M.G. Fehlings: B. Contracted Research/Research Grant (principal investigator for a drug study, collaborator or consultant and pending and current grants). If you are a PI for a drug study, report that research relationship even if those funds come to an institution.; New World Laboratories.
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LINK: Society for Neuroscience