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Teng YD, Zafonte RD. Prelude to the special issue on novel neurocircuit, cellular and molecular targets for developing functional rehabilitation therapies of neurotrauma. Exp Neurol 2021; 341:113689. [PMID: 33745921 DOI: 10.1016/j.expneurol.2021.113689] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2021] [Accepted: 03/07/2021] [Indexed: 11/15/2022]
Abstract
The poor endogenous recovery capacity and other impediments to reinstating sensorimotor or autonomic function after adult neurotrauma have perplexed modern neuroscientists, bioengineers, and physicians for over a century. However, despite limited improvement in options to mitigate acute pathophysiological sequalae, the past 20 years have witnessed marked progresses in developing efficacious rehabilitation strategies for chronic spinal cord and brain injuries. The achievement is mainly attributable to research advancements in elucidating neuroplastic mechanisms for the potential to enhance clinical prognosis. Innovative cross-disciplinary studies have established novel therapeutic targets, theoretical frameworks, and regiments to attain treatment efficacy. This Special Issue contained eight papers that described experimental and human data along with literature reviews regarding the essential roles of the conventionally undervalued factors in neural repair: systemic inflammation, neural-respiratory inflammasome axis, modulation of glutamatergic and monoaminergic neurotransmission, neurogenesis, nerve transfer, recovery neurobiology components, and the spinal cord learning, respiration and central pattern generator neurocircuits. The focus of this work was on how to induce functional recovery from manipulating these underpinnings through their interactions with secondary injury events, peripheral and supraspinal inputs, neuromusculoskeletal network, and interventions (i.e., activity training, pharmacological adjuncts, electrical stimulation, and multimodal neuromechanical, brain-computer interface [BCI] and robotic assistance [RA] devices). The evidence suggested that if key neurocircuits are therapeutically reactivated, rebuilt, and/or modulated under proper sensory feedback, neurological function (e.g., cognition, respiration, limb movement, locomotion, etc.) will likely be reanimated after neurotrauma. The efficacy can be optimized by individualizing multimodal rehabilitation treatments via BCI/RA-integrated drug administration and neuromechanical protheses.
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Affiliation(s)
- Yang D Teng
- Department of Physical Medicine and Rehabilitation, Harvard Medical School, Boston, MA, USA; Neurotrauma Recovery Research, Department of Physical Medicine and Rehabilitation, Spaulding Rehabilitation Hospital Network, Mass General Brigham, and Harvard Medical School, Boston, MA, USA; Spaulding Research Institute, Spaulding Rehabilitation Hospital Network, Boston, MA, USA.
| | - Ross D Zafonte
- Department of Physical Medicine and Rehabilitation, Harvard Medical School, Boston, MA, USA; Neurotrauma Recovery Research, Department of Physical Medicine and Rehabilitation, Spaulding Rehabilitation Hospital Network, Mass General Brigham, and Harvard Medical School, Boston, MA, USA; Spaulding Research Institute, Spaulding Rehabilitation Hospital Network, Boston, MA, USA.
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Bellák T, Fekécs Z, Török D, Táncos Z, Nemes C, Tézsla Z, Gál L, Polgári S, Kobolák J, Dinnyés A, Nógrádi A, Pajer K. Grafted human induced pluripotent stem cells improve the outcome of spinal cord injury: modulation of the lesion microenvironment. Sci Rep 2020; 10:22414. [PMID: 33376249 PMCID: PMC7772333 DOI: 10.1038/s41598-020-79846-2] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2020] [Accepted: 12/10/2020] [Indexed: 02/06/2023] Open
Abstract
Spinal cord injury results in irreversible tissue damage followed by a very limited recovery of function. In this study we investigated whether transplantation of undifferentiated human induced pluripotent stem cells (hiPSCs) into the injured rat spinal cord is able to induce morphological and functional improvement. hiPSCs were grafted intraspinally or intravenously one week after a thoracic (T11) spinal cord contusion injury performed in Fischer 344 rats. Grafted animals showed significantly better functional recovery than the control rats which received only contusion injury. Morphologically, the contusion cavity was significantly smaller, and the amount of spared tissue was significantly greater in grafted animals than in controls. Retrograde tracing studies showed a statistically significant increase in the number of FB-labeled neurons in different segments of the spinal cord, the brainstem and the sensorimotor cortex. The extent of functional improvement was inversely related to the amount of chondroitin-sulphate around the cavity and the astrocytic and microglial reactions in the injured segment. The grafts produced GDNF, IL-10 and MIP1-alpha for at least one week. These data suggest that grafted undifferentiated hiPSCs are able to induce morphological and functional recovery after spinal cord contusion injury.
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Affiliation(s)
- Tamás Bellák
- Department of Anatomy, Histology and Embryology, Faculty of Medicine, University of Szeged, Kossuth Lajos sgt. 40., 6724, Szeged, Hungary.,BioTalentum Ltd., Gödöllő, Hungary
| | - Zoltán Fekécs
- Department of Anatomy, Histology and Embryology, Faculty of Medicine, University of Szeged, Kossuth Lajos sgt. 40., 6724, Szeged, Hungary
| | - Dénes Török
- Department of Anatomy, Histology and Embryology, Faculty of Medicine, University of Szeged, Kossuth Lajos sgt. 40., 6724, Szeged, Hungary
| | | | - Csilla Nemes
- BioTalentum Ltd., Gödöllő, Hungary.,Department of Diagnostic Laboratory, State Health Centre, Military Hospital, Budapest, Hungary
| | - Zsófia Tézsla
- Department of Anatomy, Histology and Embryology, Faculty of Medicine, University of Szeged, Kossuth Lajos sgt. 40., 6724, Szeged, Hungary
| | - László Gál
- Department of Anatomy, Histology and Embryology, Faculty of Medicine, University of Szeged, Kossuth Lajos sgt. 40., 6724, Szeged, Hungary
| | | | | | - András Dinnyés
- BioTalentum Ltd., Gödöllő, Hungary.,HCEMM-USZ StemCell Research Group, Szeged, Hungary.,Department of Dermatology and Allergology, Research Institute of Translational Biomedicine, University of Szeged, Szeged, Hungary
| | - Antal Nógrádi
- Department of Anatomy, Histology and Embryology, Faculty of Medicine, University of Szeged, Kossuth Lajos sgt. 40., 6724, Szeged, Hungary.
| | - Krisztián Pajer
- Department of Anatomy, Histology and Embryology, Faculty of Medicine, University of Szeged, Kossuth Lajos sgt. 40., 6724, Szeged, Hungary
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Pajer K, Bellák T, Redl H, Nógrádi A. Neuroectodermal Stem Cells Grafted into the Injured Spinal Cord Induce Both Axonal Regeneration and Morphological Restoration via Multiple Mechanisms. J Neurotrauma 2019; 36:2977-2990. [PMID: 31111776 PMCID: PMC6791485 DOI: 10.1089/neu.2018.6332] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Spinal cord contusion injury leads to severe loss of gray and white matter and subsequent deficit of motor and sensory functions below the lesion. In this study, we investigated whether application of murine clonal embryonic neuroectodermal stem cells can prevent the spinal cord secondary damage and induce functional recovery. Stem cells (NE-GFP-4C cell line) were grafted intraspinally or intravenously immediately or one week after thoracic spinal cord contusion injury. Control animals received cell culture medium or fibrin intraspinally one week after injury. Functional tests (Basso, Beattie, Bresnahan, CatWalk®) and detailed morphological analysis were performed to evaluate the effects of grafted cells. Stem cells applied either locally or intravenously induced significantly improved functional recovery compared with their controls. Morphologically, stem cell grafting prevented the formation of secondary injury and promoted sparing of the gray and white matters. The transplanted cells integrated into the host tissue and differentiated into neurons, astrocytes, and oligodendrocytes. In intraspinally grafted animals, the corticospinal tract axons regenerated along the ventral border of the cavity and have grown several millimeters, even beyond the caudal end of the lesion. The extent of regeneration and functional improvement was inversely related to the amounts of chondroitin sulphate and ephrin-B2 molecules around the cavity and to the microglial and astrocytic reactions in the injured segment early after injury. The grafts produced glial cell derived neurotrophic factor, macrophage inflammatory protein-1a, interleukin (IL)-6 and IL-10 in a paracrine fashion for at least one week. Treating the grafted cords with neutralizing antibodies against these four factors through the use of osmotic pumps nearly completely abolished the effect of the graft. The non-significant functional improvement after function blocking is likely because the stem cell derivatives settled in the injured cord. These data suggest that grafted neuroectodermal stem cells are able to prevent the secondary spinal cord damage and induce significant regeneration via multiple mechanisms.
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Affiliation(s)
- Krisztián Pajer
- Department of Anatomy, Histology, and Embryology, Faculty of Medicine, University of Szeged, Szeged, Hungary
| | - Tamás Bellák
- Department of Anatomy, Histology, and Embryology, Faculty of Medicine, University of Szeged, Szeged, Hungary
| | - Heinz Redl
- Ludwig Boltzmann Institute for Experimental and Clinical Traumatology, Vienna, Austria
| | - Antal Nógrádi
- Department of Anatomy, Histology, and Embryology, Faculty of Medicine, University of Szeged, Szeged, Hungary.,Ludwig Boltzmann Institute for Experimental and Clinical Traumatology, Vienna, Austria
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Li Y, Yao D, Zhang J, Liu B, Zhang L, Feng H, Li B. The Effects of Epidermal Neural Crest Stem Cells on Local Inflammation Microenvironment in the Defected Sciatic Nerve of Rats. Front Mol Neurosci 2017; 10:133. [PMID: 28588447 PMCID: PMC5438963 DOI: 10.3389/fnmol.2017.00133] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2017] [Accepted: 04/20/2017] [Indexed: 12/21/2022] Open
Abstract
Cell-based therapy is a promising strategy for the repair of peripheral nerve injuries (PNIs). epidermal neural crest stems cells (EPI-NCSCs) are thought to be important donor cells for repairing PNI in different animal models. Following PNI, inflammatory response is important to regulate the repair process. However, the effects of EPI-NCSCs on regulation of local inflammation microenviroment have not been investigated extensively. In the present study, these effects were studied by using 10 mm defected sciatic nerve, which was bridged with 15 mm artificial nerve composed of EPI-NCSCs, extracellular matrix (ECM) and poly (lactide-co-glycolide) (PLGA). Then the expression of pro- and anti-inflammatory cytokines, polarization of macrophages, regulation of fibroblasts and shwann cells (SCs) were assessed by western blot, immunohistochemistry, immunofluorescence staining at 1, 3, 7 and 21 days after bridging. The structure and the function of the bridged nerve were determined by observation under light microscope and by examination of right lateral foot retraction time (LFRT), sciatic function index (SFI), gastrocnemius wet weight and electrophysiology at 9 weeks. After bridging with EPI-NCSCs, the expression of anti-inflammatory cytokines (IL-4 and IL-13) was increased, but decreased for pro-inflammatory cytokines (IL-6 and TNF-α) compared to the control bridging, which was consistent with increase of M2 macrophages and decrease of M1 macrophages at 7 days after transplantation. Likewise, myelin-formed SCs were significantly increased, but decreased for the activated fibroblasts in their number at 21 days. The recovery of structure and function of nerve bridged with EPI-NCSCs was significantly superior to that of DMEM. These results indicated that EPI-NCSCs could be able to regulate and provide more suitable inflammation microenvironment for the repair of defected sciatic nerve.
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Affiliation(s)
- Yue Li
- Department of Neurosurgery, Southwest Hospital/State Key Laboratory of Trauma, Burns and Combined Injury, Third Military Medical UniversityChongqing, China
| | - Dongdong Yao
- Research Institute of Surgery, Daping Hospital/State Key Laboratory of Trauma, Burns and Combined Injury, Third Military Medical UniversityChongqing, China.,School of Life Sciences/Key Laboratory of Freshwater Fish Reproduction and Development of Education Ministry, Southwest UniversityChongqing, China
| | - Jieyuan Zhang
- Research Institute of Surgery, Daping Hospital/State Key Laboratory of Trauma, Burns and Combined Injury, Third Military Medical UniversityChongqing, China
| | - Bin Liu
- School of Life Sciences/Key Laboratory of Freshwater Fish Reproduction and Development of Education Ministry, Southwest UniversityChongqing, China
| | - Lu Zhang
- Children's Hospital of Chongqing Medical University/Ministry of Education Key Laboratory of Child Development and Disorders, Chongqing Medical UniversityChongqing, China
| | - Hua Feng
- Department of Neurosurgery, Southwest Hospital/State Key Laboratory of Trauma, Burns and Combined Injury, Third Military Medical UniversityChongqing, China
| | - Bingcang Li
- Research Institute of Surgery, Daping Hospital/State Key Laboratory of Trauma, Burns and Combined Injury, Third Military Medical UniversityChongqing, China
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Mesenchymal Stem Cells Enhance Nerve Regeneration in a Rat Sciatic Nerve Repair and Hindlimb Transplant Model. Sci Rep 2016; 6:31306. [PMID: 27510321 PMCID: PMC4980673 DOI: 10.1038/srep31306] [Citation(s) in RCA: 70] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2016] [Accepted: 07/18/2016] [Indexed: 01/16/2023] Open
Abstract
This study investigates the efficacy of local and intravenous mesenchymal stem cell (MSC) administration to augment neuroregeneration in both a sciatic nerve cut-and-repair and rat hindlimb transplant model. Bone marrow-derived MSCs were harvested and purified from Brown-Norway (BN) rats. Sciatic nerve transections and repairs were performed in three groups of Lewis (LEW) rats: negative controls (n = 4), local MSCs (epineural) injection (n = 4), and systemic MSCs (intravenous) injection (n = 4). Syngeneic (LEW-LEW) (n = 4) and allogeneic (BN-LEW) (n = 4) hindlimb transplants were performed and assessed for neuroregeneration after local or systemic MSC treatment. Rats undergoing sciatic nerve cut-and-repair and treated with either local or systemic injection of MSCs had significant improvement in the speed of recovery of compound muscle action potential amplitudes and axon counts when compared with negative controls. Similarly, rats undergoing allogeneic hindlimb transplants treated with local injection of MSCs exhibited significantly increased axon counts. Similarly, systemic MSC treatment resulted in improved nerve regeneration following allogeneic hindlimb transplants. Systemic administration had a more pronounced effect on electromotor recovery while local injection was more effective at increasing fiber counts, suggesting different targets of action. Local and systemic MSC injections significantly improve the pace and degree of nerve regeneration after nerve injury and hindlimb transplantation.
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Myers SA, Bankston AN, Burke DA, Ohri SS, Whittemore SR. Does the preclinical evidence for functional remyelination following myelinating cell engraftment into the injured spinal cord support progression to clinical trials? Exp Neurol 2016; 283:560-72. [PMID: 27085393 DOI: 10.1016/j.expneurol.2016.04.009] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2016] [Revised: 04/06/2016] [Accepted: 04/07/2016] [Indexed: 02/08/2023]
Abstract
This article reviews all historical literature in which rodent-derived myelinating cells have been engrafted into the contused adult rodent spinal cord. From 2500 initial PubMed citations identified, human cells grafts, bone mesenchymal stem cells, olfactory ensheathing cells, non-myelinating cell grafts, and rodent grafts into hemisection or transection models were excluded, resulting in the 67 studies encompassed in this review. Forty five of those involved central nervous system (CNS)-derived cells, including neural stem progenitor cells (NSPCs), neural restricted precursor cells (NRPs) or oligodendrocyte precursor cells (OPCs), and 22 studies involved Schwann cells (SC). Of the NSPC/NPC/OPC grafts, there was no consistency with respect to the types of cells grafted and/or the additional growth factors or cells co-grafted. Enhanced functional recovery was reported in 31/45 studies, but only 20 of those had appropriate controls making conclusive interpretation of the remaining studies impossible. Of those 20, 19 were properly powered and utilized appropriate statistical analyses. Ten of those 19 studies reported the presence of graft-derived myelin, 3 reported evidence of endogenous remyelination or myelin sparing, and 2 reported both. For the SC grafts, 16/21 reported functional improvement, with 11 having appropriate cellular controls and 9/11 using proper statistical analyses. Of those 9, increased myelin was reported in 6 studies. The lack of consistency and replication among these preclinical studies are discussed with respect to the progression of myelinating cell transplantation therapies into the clinic.
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Affiliation(s)
- Scott A Myers
- 511 S. Floyd St., MDR 623, Kentucky Spinal Cord Injury Research Center and Department of Neurological Surgery, University of Louisville, School of Medicine, Louisville, KY 40202, USA
| | - Andrew N Bankston
- 511 S. Floyd St., MDR 623, Kentucky Spinal Cord Injury Research Center and Department of Neurological Surgery, University of Louisville, School of Medicine, Louisville, KY 40202, USA
| | - Darlene A Burke
- 511 S. Floyd St., MDR 623, Kentucky Spinal Cord Injury Research Center and Department of Neurological Surgery, University of Louisville, School of Medicine, Louisville, KY 40202, USA
| | - Sujata Saraswat Ohri
- 511 S. Floyd St., MDR 623, Kentucky Spinal Cord Injury Research Center and Department of Neurological Surgery, University of Louisville, School of Medicine, Louisville, KY 40202, USA
| | - Scott R Whittemore
- 511 S. Floyd St., MDR 623, Kentucky Spinal Cord Injury Research Center and Department of Neurological Surgery, University of Louisville, School of Medicine, Louisville, KY 40202, USA.
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Vilariño-Feltrer G, Martínez-Ramos C, Monleón-de-la-Fuente A, Vallés-Lluch A, Moratal D, Barcia Albacar JA, Monleón Pradas M. Schwann-cell cylinders grown inside hyaluronic-acid tubular scaffolds with gradient porosity. Acta Biomater 2016; 30:199-211. [PMID: 26518102 DOI: 10.1016/j.actbio.2015.10.040] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2015] [Revised: 10/21/2015] [Accepted: 10/26/2015] [Indexed: 11/19/2022]
Abstract
Cell transplantation therapies in the nervous system are frequently hampered by glial scarring and cell drain from the damaged site, among others. To improve this situation, new biomaterials may be of help. Here, novel single-channel tubular conduits based on hyaluronic acid (HA) with and without poly-l-lactide acid fibers in their lumen were fabricated. Rat Schwann cells were seeded within the conduits and cultured for 10days. The conduits possessed a three-layered porous structure that impeded the leakage of the cells seeded in their interior and made them impervious to cell invasion from the exterior, while allowing free transport of nutrients and other molecules needed for cell survival. The channel's surface acted as a template for the formation of a cylindrical sheath-like tapestry of Schwann cells continuously spanning the whole length of the lumen. Schwann-cell tubes having a diameter of around 0.5mm and variable lengths can thus be generated. This structure is not found in nature and represents a truly engineered tissue, the outcome of the specific cell-material interactions. The conduits might be useful to sustain and protect cells for transplantation, and the biohybrids here described, together with neuronal precursors, might be of help in building bridges across significant distances in the central and peripheral nervous system. STATEMENT OF SIGNIFICANCE The paper entitled "Schwann-cell cylinders grown inside hyaluronic-acid tubular scaffolds with gradient porosity" reports on the development of a novel tubular scaffold and on how this scaffold acts on Schwann cells seeded in its interior as a template to produce macroscopic hollow continuous cylinders of tightly joined Schwann cells. This cellular structure is not found in nature and represents a truly engineered novel tissue, which obtains as a consequence of the specific cell-material interactions within the scaffold.
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Affiliation(s)
- G Vilariño-Feltrer
- Center for Biomaterials and Tissue Engineering, Universitat Politècnica de València, Cno. de Vera s/n, 46022 Valencia, Spain
| | - C Martínez-Ramos
- Center for Biomaterials and Tissue Engineering, Universitat Politècnica de València, Cno. de Vera s/n, 46022 Valencia, Spain
| | - A Monleón-de-la-Fuente
- Center for Biomaterials and Tissue Engineering, Universitat Politècnica de València, Cno. de Vera s/n, 46022 Valencia, Spain
| | - A Vallés-Lluch
- Center for Biomaterials and Tissue Engineering, Universitat Politècnica de València, Cno. de Vera s/n, 46022 Valencia, Spain
| | - D Moratal
- Center for Biomaterials and Tissue Engineering, Universitat Politècnica de València, Cno. de Vera s/n, 46022 Valencia, Spain
| | - J A Barcia Albacar
- Servicio de Neurocirugía, Hospital Clínico San Carlos, Instituto de Investigación Sanitaria San Carlos (IdISSC), C/ Profesor Martín Lagos, S/N, Madrid 28040, Spain
| | - M Monleón Pradas
- Center for Biomaterials and Tissue Engineering, Universitat Politècnica de València, Cno. de Vera s/n, 46022 Valencia, Spain.
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Tabakow P, Raisman G, Fortuna W, Czyz M, Huber J, Li D, Szewczyk P, Okurowski S, Miedzybrodzki R, Czapiga B, Salomon B, Halon A, Li Y, Lipiec J, Kulczyk A, Jarmundowicz W. Functional regeneration of supraspinal connections in a patient with transected spinal cord following transplantation of bulbar olfactory ensheathing cells with peripheral nerve bridging. Cell Transplant 2014; 23:1631-55. [PMID: 25338642 DOI: 10.3727/096368914x685131] [Citation(s) in RCA: 166] [Impact Index Per Article: 16.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Treatment of patients sustaining a complete spinal cord injury remains an unsolved clinical problem because of the lack of spontaneous regeneration of injured central axons. A 38-year-old man sustained traumatic transection of the thoracic spinal cord at upper vertebral level Th9. At 21 months after injury, the patient presented symptoms of a clinically complete spinal cord injury (American Spinal Injury Association class A-ASIA A). One of the patient's olfactory bulbs was removed and used to derive a culture containing olfactory ensheathing cells and olfactory nerve fibroblasts. Following resection of the glial scar, the cultured cells were transplanted into the spinal cord stumps above and below the injury and the 8-mm gap bridged by four strips of autologous sural nerve. The patient underwent an intense pre- and postoperative neurorehabilitation program. No adverse effects were seen at 19 months postoperatively, and unexpectedly, the removal of the olfactory bulb did not lead to persistent unilateral anosmia. The patient improved from ASIA A to ASIA C. There was improved trunk stability, partial recovery of the voluntary movements of the lower extremities, and an increase of the muscle mass in the left thigh, as well as partial recovery of superficial and deep sensation. There was also some indication of improved visceral sensation and improved vascular autoregulation in the left lower limb. The pattern of recovery suggests functional regeneration of both efferent and afferent long-distance fibers. Imaging confirmed that the grafts had bridged the left side of the spinal cord, where the majority of the nerve grafts were implanted, and neurophysiological examinations confirmed the restitution of the integrity of the corticospinal tracts and the voluntary character of recorded muscle contractions. To our knowledge, this is the first clinical indication of the beneficial effects of transplanted autologous bulbar cells.
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Affiliation(s)
- Pawel Tabakow
- Department of Neurosurgery, Wroclaw Medical University, Wroclaw, Poland
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Altinova H, Möllers S, Führmann T, Deumens R, Bozkurt A, Heschel I, Damink LHHO, Schügner F, Weis J, Brook GA. Functional improvement following implantation of a microstructured, type-I collagen scaffold into experimental injuries of the adult rat spinal cord. Brain Res 2014; 1585:37-50. [PMID: 25193604 DOI: 10.1016/j.brainres.2014.08.041] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2014] [Revised: 08/10/2014] [Accepted: 08/14/2014] [Indexed: 12/14/2022]
Abstract
The formation of cystic cavitation following severe spinal cord injury (SCI) constitutes one of the major barriers to successful axonal regeneration and tissue repair. The development of bioengineered scaffolds that assist in the bridging of such lesion-induced gaps may contribute to the formulation of combination strategies aimed at promoting functional tissue repair. Our previous in vitro investigations have demonstrated the directed axon regeneration and glial migration supporting properties of microstructured collagen scaffold that had been engineered to possess mechanical properties similar to those of spinal cord tissues. Here, the effect of implanting the longitudinally orientated scaffold into unilateral resection injuries (2mm long) of the mid-cervical lateral funiculus of adult rats has been investigated using behavioural and correlative morphological techniques. The resection injuries caused an immediate and long lasting (up to 12 weeks post injury) deficit of food pellet retrieval by the ipsilateral forepaw. Implantation of the orientated collagen scaffold promoted a significant improvement in pellet retrieval by the ipsilateral forepaw at 6 weeks which continued to improve up to 12 weeks post injury. In contrast, implantation of a non-orientated gelatine scaffold did not result in significant functional improvement. Surprisingly, the improved motor performance was not correlated with the regeneration of lesioned axons through the implanted scaffold. This observation supports the notion that biomaterials may support functional recovery by mechanisms other than simple bridging of the lesion site, such as the local sprouting of injured, or even non-injured fibres.
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Affiliation(s)
- Haktan Altinova
- Department of Neurology, Uniklinik Aachen, Aachen, Germany; Department of Neurosurgery, Evangelic Hospital Bethel, Bielefeld, Germany; Institute for Neuropathology, Uniklinik Aachen, Aachen, Germany.
| | - Sven Möllers
- Department of Neurology, Uniklinik Aachen, Aachen, Germany; RNL Europe GmbH, Kleinmachnow, Germany
| | - Tobias Führmann
- Department of Neurology, Uniklinik Aachen, Aachen, Germany; Donnelly Centre for Cellular & Biomolecular Research, University of Toronto, ON, Canada
| | - Ronald Deumens
- Institute of Neuroscience, Université Catholique de Louvain, Brussels, Belgium; Institute for Neuropathology, Uniklinik Aachen, Aachen, Germany; Jülich-Aachen Research Alliance - Translational Brain Medicine (JARA Brain), Germany
| | - Ahmet Bozkurt
- Department of Plastic Surgery, Reconstructive and Hand Surgery, Burn Centre, Uniklinik Aachen, Aachen, Germany; Institute for Neuropathology, Uniklinik Aachen, Aachen, Germany; Jülich-Aachen Research Alliance - Translational Brain Medicine (JARA Brain), Germany
| | | | | | | | - Joachim Weis
- Institute for Neuropathology, Uniklinik Aachen, Aachen, Germany; Jülich-Aachen Research Alliance - Translational Brain Medicine (JARA Brain), Germany
| | - Gary A Brook
- Department of Neurology, Uniklinik Aachen, Aachen, Germany; Institute for Neuropathology, Uniklinik Aachen, Aachen, Germany; Jülich-Aachen Research Alliance - Translational Brain Medicine (JARA Brain), Germany
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Estrada V, Brazda N, Schmitz C, Heller S, Blazyca H, Martini R, Müller HW. Long-lasting significant functional improvement in chronic severe spinal cord injury following scar resection and polyethylene glycol implantation. Neurobiol Dis 2014; 67:165-79. [PMID: 24713436 DOI: 10.1016/j.nbd.2014.03.018] [Citation(s) in RCA: 59] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2014] [Revised: 03/17/2014] [Accepted: 03/28/2014] [Indexed: 01/04/2023] Open
Abstract
We identified a suitable biomatrix that improved axon regeneration and functional outcome after partial (moderate) and complete (severe) chronic spinal cord injury (SCI) in rat. Five weeks after dorsal thoracic hemisection injury the lesion scar was resected via aspiration and the resulting cavity was filled with different biopolymers such as Matrigel™, alginate-hydrogel and polyethylene glycol 600 (PEG) all of which have not previously been used as sole graft-materials in chronic SCI. Immunohistological staining revealed marked differences between these compounds regarding axon regeneration, invasion/elongation of astrocytes, fibroblasts, endothelial and Schwann cells, revascularization, and collagen deposition. According to axon regeneration-supporting effects, the biopolymers could be ranked in the order PEG>>alginate-hydrogel>Matrigel™. Even after complete chronic transection, the PEG-bridge allowed long-distance axon regeneration through the grafted area and for, at least, 1cm beyond the lesion/graft border. As revealed by electron microscopy, bundles of regenerating axons within the matrix area received myelin ensheathment from Schwann cells. The beneficial effects of PEG-implantation into the resection-cavity were accompanied by long-lasting significant locomotor improvement over a period of 8months. Following complete spinal re-transection at the rostral border of the PEG-graft the locomotor recovery was aborted, suggesting a functional role of regenerated axons in the initial locomotor improvement. In conclusion, scar resection and subsequent implantation of PEG into the generated cavity leads to tissue recovery, axon regeneration, myelination and functional improvement that have not been achieved before in severe chronic SCI.
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Affiliation(s)
- Veronica Estrada
- Molecular Neurobiology Laboratory, Department of Neurology, Heinrich-Heine-University Medical Center Düsseldorf, Moorenstr. 5, 40225 Düsseldorf, Germany
| | - Nicole Brazda
- Molecular Neurobiology Laboratory, Department of Neurology, Heinrich-Heine-University Medical Center Düsseldorf, Moorenstr. 5, 40225 Düsseldorf, Germany
| | - Christine Schmitz
- Molecular Neurobiology Laboratory, Department of Neurology, Heinrich-Heine-University Medical Center Düsseldorf, Moorenstr. 5, 40225 Düsseldorf, Germany
| | - Silja Heller
- Molecular Neurobiology Laboratory, Department of Neurology, Heinrich-Heine-University Medical Center Düsseldorf, Moorenstr. 5, 40225 Düsseldorf, Germany
| | - Heinrich Blazyca
- Department of Neurology, Developmental Neurobiology, University Medical Center Würzburg, Josef-Schneider-Str. 11, 97080 Würzburg, Germany
| | - Rudolf Martini
- Department of Neurology, Developmental Neurobiology, University Medical Center Würzburg, Josef-Schneider-Str. 11, 97080 Würzburg, Germany
| | - Hans Werner Müller
- Molecular Neurobiology Laboratory, Department of Neurology, Heinrich-Heine-University Medical Center Düsseldorf, Moorenstr. 5, 40225 Düsseldorf, Germany.
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11
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LIU GUOMIN, WANG XUKAI, SHAO GUOXI, LIU QINYI. Genetically modified Schwann cells producing glial cell line-derived neurotrophic factor inhibit neuronal apoptosis in rat spinal cord injury. Mol Med Rep 2014; 9:1305-12. [DOI: 10.3892/mmr.2014.1963] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2013] [Accepted: 01/31/2014] [Indexed: 11/06/2022] Open
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English D, Sharma NK, Sharma K, Anand A. Neural stem cells-trends and advances. J Cell Biochem 2013; 114:764-72. [PMID: 23225161 DOI: 10.1002/jcb.24436] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2012] [Accepted: 10/23/2012] [Indexed: 12/12/2022]
Abstract
For many years, accepted dogma held that brain is a static organ with no possibility of regeneration of cells in injured or diseased human brain. However, recent preclinical reports have shown regenerative potential of neural stem cells using various injury models. This has resulted in renewed hope for those suffering from spinal cord injury and neural damage. As the potential of stem cell therapy gained impact, these claims, in particular, led to widespread enthusiasm that acute and chronic injury of the nervous system would soon be a problem of the past. The devastation caused by injury or diseases of the brain and spinal cord led to wide premature acceptance that "neural stem cells (NSCs)" derived from embryonic, fetal or adult sources would soon be effective in reversing neural and spinal trauma. However, neural therapy with stem cells has not been realized to its fullest extent. Although, discrete population of regenerative stem cells seems to be present in specific areas of human brain, the function of these cells is unclear. However, similar cells in animals seem to play important role in postnatal growth as well as recovery of neural tissue from injury, anoxia, or disease.
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Affiliation(s)
- Denis English
- Foundation for Florida Development and Research, Palmetto, Florida
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13
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Gnavi S, Barwig C, Freier T, Haastert-Talini K, Grothe C, Geuna S. The use of chitosan-based scaffolds to enhance regeneration in the nervous system. INTERNATIONAL REVIEW OF NEUROBIOLOGY 2013; 109:1-62. [PMID: 24093605 DOI: 10.1016/b978-0-12-420045-6.00001-8] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Various biomaterials have been proposed to build up scaffolds for promoting neural repair. Among them, chitosan, a derivative of chitin, has been raising more and more interest among basic and clinical scientists. A number of studies with neuronal and glial cell cultures have shown that this biomaterial has biomimetic properties, which make it a good candidate for developing innovative devices for neural repair. Yet, in vivo experimental studies have shown that chitosan can be successfully used to create scaffolds that promote regeneration both in the central and in the peripheral nervous system. In this review, the relevant literature on the use of chitosan in the nervous tissue, either alone or in combination with other components, is overviewed. Altogether, the promising in vitro and in vivo experimental results make it possible to foresee that time for clinical trials with chitosan-based nerve regeneration-promoting devices is approaching quickly.
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Affiliation(s)
- Sara Gnavi
- Department of Clinical and Biological Sciences, Neuroscience Institute of the Cavalieri Ottolenghi Foundation (NICO), University of Turin, Ospedale San Luigi, Regione Gonzole 10, Orbassano (TO), Italy
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14
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Sun T, Ye C, Zhang Z, Wu J, Huang H. Cotransplantation of Olfactory Ensheathing Cells and Schwann Cells Combined with Treadmill Training Promotes Functional Recovery in Rats with Contused Spinal Cords. Cell Transplant 2013; 22 Suppl 1:S27-38. [PMID: 24044361 DOI: 10.3727/096368913x672118] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
The present study investigated the ability of cotransplantation of Schwann cells (SCs) and olfactory ensheathing cells (OECs) combined with treadmill training in facilitating neuronal plasticity and promoting hindlimb function recovery of subacute moderate thoracic (T10) spinal cord contusion in rats. Two weeks postinjury, SCs were injected directly into the lesion, while OECs were injected into the adjacent tissues. The treadmill training with the rats began postinjury on day 7, with each session lasting 20 ± 10 min per day, 5 days per week, for 10 weeks. At the 11th week postinjury, OECs were found migrating longitudinally and laterally from the injection site to the injury site through the gray and white matter, while some traveled along the central canal or pia. The SCs remained densely packed and concentrated at the transplant site. The transplanted SCs supported ingrowth of numerous, densely populated neurofilament-positive (NF+), MBP+ axons. The OECs promoted elongation of moderate NF+, GAP-43+ axons and a few MBP+ axons in parallel with OEC processes. The GFAP immunoreactivity in the spared tissue surrounding the graft of SCs and OECs at the lesion site was less intense than that in the DMEM group. Treadmill training had no effect on GFAP immunoreactivity. Treadmill training increased the number of TH-immunoreactive neurons in the gray matter of L2 spinal cord. Moreover, cotransplantation of OECs and SCs significantly increased the BBB score during 5–8 weeks postinjury alongside treadmill training between 5 and 11 weeks. Cotransplantation of OECs and SCs combined with treadmill training resulted in the highest BBB score at 4 and 11 weeks. The study details the differential mechanisms of neuronal plasticity: ( 1 ) axon growth and remyelination induced by cotransplantation of OECs and SCs and ( 2 ) neuron plasticity below the lesion enhanced by treadmill training. The synergistic effects of the combined strategy enhance functional recovery. This manuscript is published as part of the International Association of Neurorestoratology (IANR) supplement issue of Cell Transplantation.
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Affiliation(s)
- Tiansheng Sun
- Orthopaedic Department, The Beijing Army General Hospital, Beijing, China
| | - Chaoqun Ye
- Orthopaedic Department, The Beijing Army General Hospital, Beijing, China
| | - Zhicheng Zhang
- Orthopaedic Department, The Beijing Army General Hospital, Beijing, China
| | - Jun Wu
- Orthopaedic Department, The Beijing Army General Hospital, Beijing, China
| | - Hongyun Huang
- Beijing Hongtianji Neuroscience Academy, Beijing, China
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15
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Joosten EAJ. Biodegradable biomatrices and bridging the injured spinal cord: the corticospinal tract as a proof of principle. Cell Tissue Res 2012; 349:375-95. [PMID: 22411698 PMCID: PMC3375422 DOI: 10.1007/s00441-012-1352-5] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2011] [Accepted: 01/27/2012] [Indexed: 12/12/2022]
Abstract
Important advances in the development of smart biodegradable implants for axonal regeneration after spinal cord injury have recently been reported. These advances are evaluated in this review with special emphasis on the regeneration of the corticospinal tract. The corticospinal tract is often considered the ultimate challenge in demonstrating whether a repair strategy has been successful in the regeneration of the injured mammalian spinal cord. The extensive know-how of factors and cells involved in the development of the corticospinal tract, and the advances made in material science and tissue engineering technology, have provided the foundations for the optimization of the biomatrices needed for repair. Based on the findings summarized in this review, the future development of smart biodegradable bridges for CST regrowth and regeneration in the injured spinal cord is discussed.
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Affiliation(s)
- Elbert A J Joosten
- Department of Anesthesiology, Pain Management and Research Center, Maastricht University Medical Hospital, Maastricht, The Netherlands.
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Park SS, Lee YJ, Lee SH, Lee D, Choi K, Kim WH, Kweon OK, Han HJ. Functional recovery after spinal cord injury in dogs treated with a combination of Matrigel and neural-induced adipose-derived mesenchymal Stem cells. Cytotherapy 2012; 14:584-97. [PMID: 22348702 DOI: 10.3109/14653249.2012.658913] [Citation(s) in RCA: 85] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
BACKGROUND AIMS Previous studies have reported that scaffold or cell-based transplantation may improve functional recovery following spinal cord injury (SCI), but these results were based on neuronal regeneration and cell replacement. In this study, we investigated whether a combination of Matrigel and neural-induced mesenchymal stem cells (NMSC) improved hindlimb function in dogs with SCI, and what mechanisms were involved. METHODS We pre-differentiated canine adipose-derived mesenchymal stem cells into NMSC. A total of 12 dogs subjected to SCI procedures were assigned to one of the following three transplantation treatment groups: phosphate-buffered saline (PBS); Matrigel; or Matrigel seeded with NMSC. Treatment occurred 1 week after SCI. Basso, Beattie and Bresnahan (B.B.B.) and Tarlov scores, histopathology, immunofluorescence staining and Western blot analysis were used to evaluate the treatment effects. RESULTS Compared with dogs administered PBS or Matrigel alone, dogs treated with Matrigel + NMSC showed significantly better functional recovery 8 weeks after transplantation. Histology and immunochemical analysis revealed that the combination of Matrigel + NMSC reduced fibrosis from secondary injury processes and improved neuronal regeneration more than the other treatments. In addition, the combination of Matrigel + NMSC decreased the expression of inflammation and/or astrogliosis markers. Increased expressions of intracellular molecules related to neuronal extension, neuronal markers and neurotrophic factors were also found in the Matrigel + NMSC group. However, the expression of nestin as a neural stem cell marker was increased with Matrigel alone. CONCLUSIONS The combination of Matrigel + NMSC produced beneficial effects in dogs with regard to functional recovery following SCI through enhancement of anti-inflammation, anti-astrogliosis, neuronal extension and neuronal regeneration effects.
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Affiliation(s)
- Sung-Su Park
- Department of Veterinary Surgery, College of Veterinary Medicine, Seoul National University, Seoul, Republic of Korea
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17
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Dietz V, Curt A. Translating preclinical approaches into human application. HANDBOOK OF CLINICAL NEUROLOGY 2012; 109:399-409. [PMID: 23098727 DOI: 10.1016/b978-0-444-52137-8.00025-5] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
In recent decades, several novel approaches of spinal cord repair have revealed promising findings in animal models. However, for a successful translation of these into a clinical trial in humans the specific conditions pertaining to human spinal cord injuries (SCI) have to be appreciated. Firstly, transection of the spinal cord is commonly applied in animal models, whereas spinal cord contusion is the predominant type of injury in humans, and generally leads to more extensive injury in two to three spinal cord segments. Secondly, the quadrupedal organization of locomotion in animals and the more complex autonomic functions in humans challenge the translation of animal behavior into recovery from human SCI. Thirdly, so far, no adequate animal model has been developed to resemble spastic movement disorder in human SCI. Fourthly, the extensive damage to spinal motor neurons and nerve roots in human cervical and thoracolumbar in spine trauma is but little addressed in current translational studies. This damage has direct implications for rehabilitation and repair strategies. Fifthly, there is increasing evidence for a neuronal dysfunction below the level of the lesion in chronic complete SCI. The relevance of this dysfunction for a regeneration-inducing treatment needs to be investigated. Lastly, an approach to facilitate an appropriate reconnection of regenerating tract fibers by functional training in the postacute stage has yet to be confirmed.
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Affiliation(s)
- Volker Dietz
- Balgrist University Hospital, Zurich, Switzerland.
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Becker D, McDonald JW. Approaches to repairing the damaged spinal cord: overview. HANDBOOK OF CLINICAL NEUROLOGY 2012; 109:445-61. [PMID: 23098730 DOI: 10.1016/b978-0-444-52137-8.00028-0] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Affecting young people during the most productive period of their lives, spinal cord injury (SCI) is a devastating problem for modern society. In the past, treating SCI seemed frustrating and hopeless because of the tremendous morbidity and mortality, life-shattering impact, and limited therapeutic options associated with the condition. Today, however, an understanding of the underlying pathophysiological mechanisms, the development of neuroprotective interventions, and progress toward regenerative interventions are increasing hope for functional restoration. In this chapter, we provide an overview of various repair strategies for the injured spinal cord. Special attention will be paid to strategies that promote spontaneous regeneration, including functional electrical stimulation, cell replacement, neuroprotection, and remyelination. The concept that limited rebuilding can provide a disproportionate improvement in quality of life is emphasized throughout. New surgical procedures, pharmacological treatments, and functional neuromuscular stimulation methods have evolved over the last decades and can improve functional outcomes after spinal cord injury; however, limiting secondary injury remains the primary goal. Tissue replacement strategies, including the use of embryonic stem cells, become an important tool and can restore function in animal models. Controlled clinical trials are now required to confirm these observations. The ultimate goal is to harness the body's own potential to replace lost central nervous system cells by activation of endogenous progenitor cell repair mechanisms.
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Affiliation(s)
- Daniel Becker
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD, USA
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Chen BK, Knight AM, Madigan NN, Gross L, Dadsetan M, Nesbitt JJ, Rooney GE, Currier BL, Yaszemski MJ, Spinner RJ, Windebank AJ. Comparison of polymer scaffolds in rat spinal cord: a step toward quantitative assessment of combinatorial approaches to spinal cord repair. Biomaterials 2011; 32:8077-86. [PMID: 21803415 DOI: 10.1016/j.biomaterials.2011.07.029] [Citation(s) in RCA: 61] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2011] [Accepted: 07/08/2011] [Indexed: 01/10/2023]
Abstract
The transected rat thoracic (T(9/10)) spinal cord model is a platform for quantitatively comparing biodegradable polymer scaffolds. Schwann cell-loaded scaffolds constructed from poly (lactic co-glycolic acid) (PLGA), poly(ɛ-caprolactone fumarate) (PCLF), oligo(polyethylene glycol) fumarate (OPF) hydrogel or positively charged OPF (OPF+) hydrogel were implanted into the model. We demonstrated that the mechanical properties (3-point bending and stiffness) of OPF and OPF + hydrogels closely resembled rat spinal cord. After one month, tissues were harvested and analyzed by morphometry of neurofilament-stained sections at rostral, midlevel, and caudal scaffold. All polymers supported axonal growth. Significantly higher numbers of axons were found in PCLF (P < 0.01) and OPF+ (P < 0.05) groups, compared to that of the PLGA group. OPF + polymers showed more centrally distributed axonal regeneration within the channels while other polymers (PLGA, PCLF and OPF) tended to show more evenly dispersed axons within the channels. The centralized distribution was associated with significantly more axons regenerating (P < 0.05). Volume of scar and cyst rostral and caudal to the implanted scaffold was measured and compared. There were significantly smaller cyst volumes in PLGA compared to PCLF groups. The model provides a quantitative basis for assessing individual and combined tissue engineering strategies.
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Affiliation(s)
- Bingkun K Chen
- Mayo Clinic College of Medicine, Department of Neurology, Mayo Clinic, Rochester, MN 55905, USA
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20
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Rooney GE, Knight AM, Madigan NN, Gross L, Chen B, Giraldo CV, Seo S, Nesbitt JJ, Dadsetan M, Yaszemski MJ, Windebank AJ. Sustained delivery of dibutyryl cyclic adenosine monophosphate to the transected spinal cord via oligo [(polyethylene glycol) fumarate] hydrogels. Tissue Eng Part A 2011; 17:1287-302. [PMID: 21198413 DOI: 10.1089/ten.tea.2010.0396] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
This study describes the use of oligo [(polyethylene glycol) fumarate] (OPF) hydrogel scaffolds as vehicles for sustained delivery of dibutyryl cyclic adenosine monophosphate (dbcAMP) to the transected spinal cord. dbcAMP was encapsulated in poly(lactic-co-glycolic acid) (PLGA) microspheres, which were embedded within the scaffolds architecture. Functionality of the released dbcAMP was assessed using neurite outgrowth assays in PC12 cells and by delivery to the transected spinal cord within OPF seven channel scaffolds, which had been loaded with Schwann cells or mesenchymal stem cells (MSCs). Our results showed that encapsulation of dbcAMP in microspheres lead to prolonged release and continued functionality in vitro. These microspheres were then successfully incorporated into OPF scaffolds and implanted in the transected thoracic spinal cord. Sustained delivery of dbcAMP inhibited axonal regeneration in the presence of Schwann cells but rescued MSC-induced inhibition of axonal regeneration. dbcAMP was also shown to reduce capillary formation in the presence of MSCs, which was coupled with significant functional improvements. Our findings demonstrate the feasibility of incorporating PLGA microsphere technology for spinal cord transection studies. It represents a novel sustained delivery mechanism within the transected spinal cord and provides a platform for potential delivery of other therapeutic agents.
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Affiliation(s)
- Gemma E Rooney
- Department of Neurology, Mayo Clinic College of Medicine, Rochester, Minnesota, USA
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Hejčl A, Jendelová P, Syková E. Experimental reconstruction of the injured spinal cord. Adv Tech Stand Neurosurg 2011:65-95. [PMID: 21997741 DOI: 10.1007/978-3-7091-0673-0_3] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
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.
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Affiliation(s)
- A Hejčl
- Institute of Experimental Medicine, Academy of Sciences of the Czech Republic, Prague, Czech Republic
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Sharp KG, Flanagan LA, Yee KM, Steward O. A re-assessment of a combinatorial treatment involving Schwann cell transplants and elevation of cyclic AMP on recovery of motor function following thoracic spinal cord injury in rats. Exp Neurol 2010; 233:625-44. [PMID: 21195070 DOI: 10.1016/j.expneurol.2010.12.020] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2010] [Revised: 12/17/2010] [Accepted: 12/22/2010] [Indexed: 11/29/2022]
Abstract
This study was undertaken as part of the NIH "Facilities of Research-Spinal Cord Injury" project to support independent replication of published studies. Here, we repeated a study reporting that a combinatorial treatment with transplants of Schwann cells, systemic delivery of Rolipram to enhance cyclic AMP levels, and intra-spinal injections of dibutyryl cyclic AMP enhanced locomotor recovery in rats after contusion injuries at the thoracic level. We compared the following experimental groups: 1) rats that received Schwann cell transplants, systemic Rolipram, and injections of db-cyclic AMP (the combined treatment group that showed the greatest improvement in function); 2) rats that received Schwann cell transplants only and implantation of empty pumps as control; 3) rats that received Rolipram only and implantation of empty pumps as control, and 4) control rats that received no treatment other than the injection of DMEM into the spinal cord and implantation of empty pumps. The principal findings reported in Pearse et al. were not replicated in that the combined treatment group did not exhibit greater recovery on any of the measures, although the group that received Schwann cells only did exhibit enhanced recovery on several of the outcome measures. The failure of the combined treatment may be due in part to less successful engraftment of Schwann cells in our study vs. Pearse et al. Issues relating to failures to replicate, especially when effect size is small, are discussed.
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Affiliation(s)
- Kelli G Sharp
- Reeve-Irvine Research Center, University of California at Irvine School of Medicine, Irvine, CA 92697-4265, USA
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Park HW, Lim MJ, Jung H, Lee SP, Paik KS, Chang MS. Human mesenchymal stem cell-derived Schwann cell-like cells exhibit neurotrophic effects, via distinct growth factor production, in a model of spinal cord injury. Glia 2010; 58:1118-32. [PMID: 20468053 DOI: 10.1002/glia.20992] [Citation(s) in RCA: 95] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Human bone marrow-derived mesenchymal stem cells (hMSCs) are considered a desirable cell source for autologous cell transplantation therapy to treat nervous system injury due to their ability to differentiate into specific cell types and render the tissue microenvironment more favorable for tissue repair by secreting various growth factors. To potentiate their possible trophic effect, hMSCs were induced without genetic modification to adopt characteristics of Schwann cells (SCs), which provide trophic support for regenerating axons. The induced hMSCs (shMSCs) adopted a SC-like morphology and expressed SC-specific proteins including the p75 neurotrophin receptor, which correlated with cell-cycle exit. In addition, shMSCs secreted higher amounts of several growth factors, such as hepatocyte growth factor (HGF) and vascular endothelial growth factor (VEGF) when compared with uninduced hMSCs. Coculture of shMSCs with Neuro2A cells significantly increased neurite outgrowth and cell proliferation but decreased cell death. Transplantation of shMSCs in an ex vivo model of spinal cord injury dramatically enhanced axonal outgrowth, which was mediated by HGF and VEGF secretion and also decreased cell death. These results demonstrate that shMSCs could serve as an endogenous source of neurotrophic growth factors to facilitate axonal regeneration while at the same time protecting the resident cells at the site of tissue injury. We propose that these induced hMSCs without genetic modification are useful for autologous cell therapy to treat nervous system injury.
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Affiliation(s)
- Hwan-Woo Park
- Department of Oral Anatomy, Dental Research Institute and School of Dentistry, Seoul National University, 28 Yeongeon-Dong, Jongno-Gu, Seoul 110-749, Republic of Korea
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Straley KS, Foo CWP, Heilshorn SC. Biomaterial design strategies for the treatment of spinal cord injuries. J Neurotrauma 2010; 27:1-19. [PMID: 19698073 DOI: 10.1089/neu.2009.0948] [Citation(s) in RCA: 225] [Impact Index Per Article: 16.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
The highly debilitating nature of spinal cord injuries has provided much inspiration for the design of novel biomaterials that can stimulate cellular regeneration and functional recovery. Many experts agree that the greatest hope for treatment of spinal cord injuries will involve a combinatorial approach that integrates biomaterial scaffolds, cell transplantation, and molecule delivery. This manuscript presents a comprehensive review of biomaterial-scaffold design strategies currently being applied to the development of nerve guidance channels and hydrogels that more effectively stimulate spinal cord tissue regeneration. To enhance the regenerative capacity of these two scaffold types, researchers are focusing on optimizing the mechanical properties, cell-adhesivity, biodegradability, electrical activity, and topography of synthetic and natural materials, and are developing mechanisms to use these scaffolds to deliver cells and biomolecules. Developing scaffolds that address several of these key design parameters will lead to more successful therapies for the regeneration of spinal cord tissue.
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Affiliation(s)
- Karin S Straley
- Chemical Engineering Department, Stanford University, Stanford, California 4305-4045, USA
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Chi GF, Kim MR, Kim DW, Jiang MH, Son Y. Schwann cells differentiated from spheroid-forming cells of rat subcutaneous fat tissue myelinate axons in the spinal cord injury. Exp Neurol 2010; 222:304-17. [DOI: 10.1016/j.expneurol.2010.01.008] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2009] [Revised: 01/07/2010] [Accepted: 01/08/2010] [Indexed: 02/07/2023]
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Wakao S, Hayashi T, Kitada M, Kohama M, Matsue D, Teramoto N, Ose T, Itokazu Y, Koshino K, Watabe H, Iida H, Takamoto T, Tabata Y, Dezawa M. Long-term observation of auto-cell transplantation in non-human primate reveals safety and efficiency of bone marrow stromal cell-derived Schwann cells in peripheral nerve regeneration. Exp Neurol 2010; 223:537-47. [PMID: 20153320 DOI: 10.1016/j.expneurol.2010.01.022] [Citation(s) in RCA: 88] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2009] [Revised: 01/25/2010] [Accepted: 01/29/2010] [Indexed: 12/13/2022]
Abstract
Based on their differentiation ability, bone marrow stromal cells (MSCs) are a good source for cell therapy. Using a cynomolgus monkey peripheral nervous system injury model, we examined the safety and efficacy of Schwann cells induced from MSCs as a source for auto-cell transplantation therapy in nerve injury. Serial treatment of monkey MSCs with reducing agents and cytokines induced their differentiation into cells with Schwann cell properties at a very high ratio. Expression of Schwann cell markers was confirmed by both immunocytochemistry and reverse transcription-polymerase chain reaction. Induced Schwann cells were used for auto-cell transplantation into the median nerve and followed-up for 1year. No abnormalities were observed in general conditions. Ki67-immunostaining revealed no sign of massive proliferation inside the grafted tube. Furthermore, (18)F-fluorodeoxygluocose-positron emission tomography scanning demonstrated no abnormal accumulation of radioactivity except in regions with expected physiologic accumulation. Restoration of the transplanted nerve was corroborated by behavior analysis, electrophysiology and histological evaluation. Our results suggest that auto-cell transplantation therapy using MSC-derived Schwann cells is safe and effective for accelerating the regeneration of transected axons and for functional recovery of injured nerves. The practical advantages of MSCs are expected to make this system applicable for spinal cord injury and other neurotrauma or myelin disorders where the acceleration of regeneration is expected to enhance functional recovery.
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Affiliation(s)
- Shohei Wakao
- Department of Stem Cell Biology and Histology, Tohoku University Graduate School of Medicine, Sendai 980-8575, Japan
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Lavdas AA, Chen J, Papastefanaki F, Chen S, Schachner M, Matsas R, Thomaidou D. Schwann cells engineered to express the cell adhesion molecule L1 accelerate myelination and motor recovery after spinal cord injury. Exp Neurol 2010; 221:206-16. [DOI: 10.1016/j.expneurol.2009.10.024] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2009] [Revised: 10/30/2009] [Accepted: 10/31/2009] [Indexed: 11/30/2022]
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28
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Rooney GE, Endo T, Ameenuddin S, Chen B, Vaishya S, Gross L, Schiefer TK, Currier BL, Spinner RJ, Yaszemski MJ, Windebank AJ. Importance of the vasculature in cyst formation after spinal cord injury. J Neurosurg Spine 2009; 11:432-7. [PMID: 19929340 DOI: 10.3171/2009.4.spine08784] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
OBJECT Glial scar and cystic formation greatly contribute to the inhibition of axonal regeneration after spinal cord injury (SCI). Attempts to promote axonal regeneration are extremely challenging in this type of hostile environment. The objective of this study was to examine the surgical methods that may be used to assess the factors that influence the level of scar and cystic formation in SCI. METHODS In the first part of this study, a complete transection was performed at vertebral level T9-10 in adult female Sprague-Dawley rats. The dura mater was either left open (control group) or was closed using sutures or hyaluronic acid. In the second part of the study, complete or subpial transection was performed, with the same dural closure technique applied to both groups. Histological analysis of longitudinal sections of the spinal cord was performed, and the percentage of scar and cyst formation was determined. RESULTS Dural closure using sutures resulted in significantly less glial scar formation (p = 0.0248), while incorporation of the subpial transection surgical technique was then shown to significantly decrease cyst formation (p < 0.0001). CONCLUSIONS In this study, the authors demonstrated the importance of the vasculature in cyst formation after spinal cord trauma and confirmed the importance of dural closure in reducing glial scar formation.
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Affiliation(s)
- Gemma E Rooney
- Department of Neurology and Molecular Neuroscience, Mayo Clinic College of Medicine, Rochester, Minnesota 55905, USA
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Krych AJ, Rooney GE, Chen B, Schermerhorn TC, Ameenuddin S, Gross L, Moore MJ, Currier BL, Spinner RJ, Friedman JA, Yaszemski MJ, Windebank AJ. Relationship between scaffold channel diameter and number of regenerating axons in the transected rat spinal cord. Acta Biomater 2009; 5:2551-9. [PMID: 19409869 PMCID: PMC2731813 DOI: 10.1016/j.actbio.2009.03.021] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2008] [Revised: 01/20/2009] [Accepted: 03/20/2009] [Indexed: 12/17/2022]
Abstract
Regeneration of endogenous axons through a Schwann cell (SC)-seeded scaffold implant has been demonstrated in the transected rat spinal cord. The formation of a cellular lining in the scaffold channel may limit the degree of axonal regeneration. Spinal cords of adult rats were transected and implanted with the SC-loaded polylactic co-glycollic acid (PLGA) scaffold implants containing seven parallel-aligned channels, either 450mum (n=19) or 660microm in diameter (n=14). Animals were sacrificed after 1, 2 and 3months. Immunohistochemistry for neurofilament expression was performed. The cross-sectional area of fibrous tissue and regenerative core was calculated. We found that the 450microm scaffolds had significantly greater axon fibers per channel at the 1month (186+/-37) and 3month (78+/-11) endpoints than the 660microm scaffolds (90+/-19 and 40+/-6, respectively) (p=0.0164 and 0.0149, respectively). The difference in the area of fibrous rim between the 450 and 660microm channels was most pronounced at the 1month endpoint, at 28,046+/-6551 and 58,633+/-7063microm(2), respectively (p=0.0105). Our study suggests that fabricating scaffolds with smaller diameter channels promotes greater regeneration over larger diameter channels. Axonal regeneration was reduced in the larger channels due to the generation of a large fibrous rim. Optimization of this scaffold environment establishes a platform for future studies of the effects of cell types, trophic factors or pharmacological agents on the regenerative capacity of the injured spinal cord.
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Affiliation(s)
- Aaron J Krych
- Department of Orthopedic Surgery, Mayo Clinic College of Medicine, Rochester, MN 55905, USA
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Teng X, Nagata I, Li HP, Kimura-Kuroda J, Sango K, Kawamura K, Raisman G, Kawano H. Regeneration of nigrostriatal dopaminergic axons after transplantation of olfactory ensheathing cells and fibroblasts prevents fibrotic scar formation at the lesion site. J Neurosci Res 2009; 86:3140-50. [PMID: 18615647 DOI: 10.1002/jnr.21767] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
The fibrotic scar formed after central nervous system injury has been considered an obstacle to axonal regeneration. The present study was designed to examine whether cell transplantation into a damaged central nervous system can reduce fibrotic scar formation and promote axonal regeneration. Nigrostriatal dopaminergic axons were unilaterally transected in rats and cultures of olfactory-ensheathing cells (OECs), and olfactory nerve fibroblasts were transplanted into the lesion site. In the absence of transplants, few tyrosine hydroxylase-immunoreactive axons extended across the lesion 2 weeks after the transection. Reactive astrocytes increased around the lesion, and a fibrotic scar containing type IV collagen deposits developed in the lesion center. The immunoreactivity of chondroitin sulfate side chains and core protein of NG2 proteoglycan increased in and around the lesion. One and 2 weeks after transection and simultaneous transplantation, dopaminergic axons regenerated across the transplanted tissues, which consisted of p75-immunoreactive OECs and fibronectin-immunoreactive fibroblasts. Reactive astrocytes and chondroitin sulfate immunoreactivity increased around the transplants, whereas the deposition of type IV collagen and fibrotic scar formation were completely prevented at the lesion site. Transplantation of meningeal fibroblasts similarly prevented the formation of the fibrotic scar, although its effect on regeneration was less potent than transplantation of OECs and olfactory nerve fibroblasts. The present results suggest that elimination of the inhibitory fibrotic scar is important for neural regeneration.
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Affiliation(s)
- Xichuan Teng
- Department of Developmental Morphology, Tokyo Metropolitan Institute for Neuroscience, Fuchu, Japan
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Nomura H, Baladie B, Katayama Y, Morshead CM, Shoichet MS, Tator CH. Delayed implantation of intramedullary chitosan channels containing nerve grafts promotes extensive axonal regeneration after spinal cord injury. Neurosurgery 2009; 63:127-41; discussion 141-3. [PMID: 18728578 DOI: 10.1227/01.neu.0000335080.47352.31] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
OBJECTIVE We describe a new strategy to promote axonal regeneration after subacute or chronic spinal cord injury consisting of intramedullary implantation of chitosan guidance channels containing peripheral nerve (PN) grafts. METHODS Chitosan channels filled with PN grafts harvested from green fluorescent protein rats were implanted in the cavity 1 week (subacute) or 4 weeks (chronic) after 50-g clip injury at T8 and were compared with similarly injured animals implanted with either unfilled channels or no channels. Functional recovery was measured weekly for 12 weeks by open-field locomotion, after which histological examination was performed. RESULTS The implanted channels with PN grafts contained a thick tissue bridge containing as many as 35,000 myelinated axons in both the subacute and chronic spinal cord injury groups, with the greatest number of axons in the channels containing PN grafts implanted subacutely. There were numerous green fluorescent protein-positive donor Schwann cells in the tissue bridges in all animals with PN grafts. Moreover, these Schwann cells had high functional capacity in terms of myelination of the axons in the channels. In addition, PN-filled chitosan channels showed excellent biocompatibility with the adjacent neural tissue and no obvious signs of degradation and minimal tissue reaction at 14 weeks after implantation. In control animals that had unfilled chitosan channels implanted, there was minimal axonal regeneration in the channels; in control animals without channels, there were large cavities in the spinal cords, and the bridges contained only a small number of axons and Schwann cells. Despite the large numbers of axons in the chitosan channel-PN graft group, there was no significant difference in functional recovery between treatment and control groups. CONCLUSION Intramedullary implantation of chitosan guidance channels containing PN grafts in the cavity after subacute spinal cord injury resulted in a thicker bridge containing a larger number of myelinated axons compared with chitosan channels alone. A chitosan channel containing PN grafts is a promising strategy for spinal cord repair.
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Affiliation(s)
- Hiroshi Nomura
- Toronto Western Research Institute, Toronto Western Hospital, Toronto, Canada
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Combinatorial strategies with Schwann cell transplantation to improve repair of the injured spinal cord. Neurosci Lett 2009; 456:124-32. [PMID: 19429147 DOI: 10.1016/j.neulet.2008.08.092] [Citation(s) in RCA: 79] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2008] [Revised: 07/29/2008] [Accepted: 08/04/2008] [Indexed: 12/11/2022]
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Lankford KL, Sasaki M, Radtke C, Kocsis JD. Olfactory ensheathing cells exhibit unique migratory, phagocytic, and myelinating properties in the X-irradiated spinal cord not shared by Schwann cells. Glia 2008; 56:1664-78. [DOI: 10.1002/glia.20718] [Citation(s) in RCA: 76] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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Nomura H, Baladie B, Katayama Y, Morshead CM, Shoichet MS, Tator CH. DELAYED IMPLANTATION OF INTRAMEDULLARY CHITOSAN CHANNELS CONTAINING NERVE GRAFTS PROMOTES EXTENSIVE AXONAL REGENERATION AFTER SPINAL CORD INJURY. Neurosurgery 2008. [DOI: 10.1227/01.neu.0000316443.88403.16] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
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Nomura H, Zahir T, Kim H, Katayama Y, Kulbatski I, Morshead CM, Shoichet MS, Tator CH. Extramedullary Chitosan Channels Promote Survival of Transplanted Neural Stem and Progenitor Cells and Create a Tissue Bridge After Complete Spinal Cord Transection. Tissue Eng Part A 2008; 14:649-65. [DOI: 10.1089/tea.2007.0180] [Citation(s) in RCA: 106] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Affiliation(s)
- Hiroshi Nomura
- Toronto Western Research Institute, Toronto Western Hospital, Toronto, Ontario, Canada
| | - Tasneem Zahir
- Department of Chemical Engineering and Applied Chemistry, University of Toronto, Toronto, Ontario, Canada
- Department of Chemistry, University of Toronto, Toronto, Ontario, Canada
- Institute of Biomaterials and Biomedical Engineering, University of Toronto, Toronto, Ontario, Canada
| | - Howard Kim
- Institute of Biomaterials and Biomedical Engineering, University of Toronto, Toronto, Ontario, Canada
- Institute of Medical Sciences, University of Toronto, Toronto, Ontario, Canada
| | | | - Iris Kulbatski
- Toronto Western Research Institute, Toronto Western Hospital, Toronto, Ontario, Canada
| | - Cindi M. Morshead
- Institute of Medical Sciences, University of Toronto, Toronto, Ontario, Canada
- Department of Surgery, University of Toronto, Toronto, Ontario, Canada
- Terrence Donnelly Center for Cellular and Biomolecular Research, University of Toronto, Toronto, Ontario, Canada
| | - Molly S. Shoichet
- Department of Chemical Engineering and Applied Chemistry, University of Toronto, Toronto, Ontario, Canada
- Department of Chemistry, University of Toronto, Toronto, Ontario, Canada
- Institute of Biomaterials and Biomedical Engineering, University of Toronto, Toronto, Ontario, Canada
- Terrence Donnelly Center for Cellular and Biomolecular Research, University of Toronto, Toronto, Ontario, Canada
| | - Charles H. Tator
- Toronto Western Research Institute, Toronto Western Hospital, Toronto, Ontario, Canada
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Konya D, Liao WL, Choi H, Yu D, Woodard MC, Newton KM, King AM, Pamir NM, Black PM, Frontera WR, Sabharwal S, Teng YD. Functional recovery in T13–L1 hemisected rats resulting from peripheral nerve rerouting: role of central neuroplasticity. Regen Med 2008; 3:309-27. [DOI: 10.2217/17460751.3.3.309] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Background: Functional improvements after spinal cord injury (SCI) have been reported anecdotally following neurotization, in other words, rerouting nerves proximal to injured cord segments to distal neuromuscular targets, although the underlying mechanisms remain largely unknown. Aim: To test our hypothesis that neurotization-mediated recovery is primarily attributable to CNS neuroplasticity that therefore manifests optimal response during particular therapeutic windows, we anastomosed the T12 intercostal nerve to the ipsilateral L3 nerve root 1–4 weeks after T13–L1 midline hemisection in rats. Results: While axonal tracing and electromyography revealed limited reinnervation in the target muscles, neurobehavioral function, as assessed by locomotion, extensor postural thrust and sciatic functional index of SCI rats receiving neurotization 7–10 days postinjury (n = 11), recovered to levels close to non-SCI controls with neurotization only (n = 3), beginning 3–5 weeks postanastomosis. Conversely, hindlimb deficits were unchanged in hemisected controls with sham neurotization (n = 7) or 4 weeks-delayed neurotization (n = 3) and in rats that had undergone T13–L1 transection plus bilateral anastomoses (n = 6). Conclusion: Neurotized SCI animals demonstrated multiparameters of neural reorganization in the distal lumbar cord, including enhanced proliferation of endogenous neural stem cells, increased immunoreactivity of serotonin and synaptophysin, and neurite growth/sprouting, suggesting that anastomosing functional nerves with the nerve stump emerging distal to the hemisection stimulates neuroplasticity in the dysfunctional spinal cord. Our conclusion is validated by the fact that severance of the T13–L1 contralateral cord abolished the postanastomosis functional recovery. Neurotization and its neuroplastic sequelae need to be explored further to optimize clinical strategies of post-SCI functional repair.
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Affiliation(s)
- Deniz Konya
- Division of SCI Research, VA Boston Healthcare System, Boston, MA 02132, USA
- Department of Neurosurgery, Harvard Medical School, the Brigham and Women's Hospital and Children's Hospital Boston, Boston, MA 02115, USA
- Department of Neurosurgery, Marmara University, Istanbul, Turkey
| | - Wei-Lee Liao
- Department of Neurosurgery, Harvard Medical School, the Brigham and Women's Hospital and Children's Hospital Boston, Boston, MA 02115, USA
- Department of Physical Medicine & Rehabilitation, Harvard Medical School, Spaulding Rehabilitation Hospital, Boston, MA 02114, USA
| | - Howard Choi
- Department of Neurosurgery, Harvard Medical School, the Brigham and Women's Hospital and Children's Hospital Boston, Boston, MA 02115, USA
- Department of Physical Medicine & Rehabilitation, Harvard Medical School, Spaulding Rehabilitation Hospital, Boston, MA 02114, USA
| | - Dou Yu
- Division of SCI Research, VA Boston Healthcare System, Boston, MA 02132, USA
- Department of Neurosurgery, Harvard Medical School, the Brigham and Women's Hospital and Children's Hospital Boston, Boston, MA 02115, USA
| | - Matthew C Woodard
- Division of SCI Research, VA Boston Healthcare System, Boston, MA 02132, USA
- Department of Neurosurgery, Harvard Medical School, the Brigham and Women's Hospital and Children's Hospital Boston, Boston, MA 02115, USA
| | - Kimberly M Newton
- Division of SCI Research, VA Boston Healthcare System, Boston, MA 02132, USA
- Department of Neurosurgery, Harvard Medical School, the Brigham and Women's Hospital and Children's Hospital Boston, Boston, MA 02115, USA
| | - Allyson M King
- Division of SCI Research, VA Boston Healthcare System, Boston, MA 02132, USA
- Department of Neurosurgery, Harvard Medical School, the Brigham and Women's Hospital and Children's Hospital Boston, Boston, MA 02115, USA
| | | | - Peter M Black
- Department of Neurosurgery, Harvard Medical School, the Brigham and Women's Hospital and Children's Hospital Boston, Boston, MA 02115, USA
| | - Walter R Frontera
- Department of Physical Medicine & Rehabilitation, Harvard Medical School, Spaulding Rehabilitation Hospital, Boston, MA 02114, USA
- School of Medicine, University of Puerto Rico, San Juan, PR, USA
| | - Sunil Sabharwal
- Department of Neurosurgery, Harvard Medical School, the Brigham and Women's Hospital and Children's Hospital Boston, Boston, MA 02115, USA
- Department of Physical Medicine & Rehabilitation, Harvard Medical School, Spaulding Rehabilitation Hospital, Boston, MA 02114, USA
| | - Yang D Teng
- Division of SCI Research, VA Boston Healthcare System, Boston, MA 02132, USA
- Department of Neurosurgery, Harvard Medical School, the Brigham and Women's Hospital and Children's Hospital Boston, Boston, MA 02115, USA
- Department of Physical Medicine & Rehabilitation, Harvard Medical School, Spaulding Rehabilitation Hospital, Boston, MA 02114, USA
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Feng SQ, Zhou XF, Rush RA, Ferguson IA. Graft of pre-injured sural nerve promotes regeneration of corticospinal tract and functional recovery in rats with chronic spinal cord injury. Brain Res 2008; 1209:40-8. [DOI: 10.1016/j.brainres.2008.02.075] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2008] [Revised: 02/25/2008] [Accepted: 02/26/2008] [Indexed: 11/28/2022]
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Novikova LN, Pettersson J, Brohlin M, Wiberg M, Novikov LN. Biodegradable poly-β-hydroxybutyrate scaffold seeded with Schwann cells to promote spinal cord repair. Biomaterials 2008; 29:1198-206. [DOI: 10.1016/j.biomaterials.2007.11.033] [Citation(s) in RCA: 118] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2007] [Accepted: 11/24/2007] [Indexed: 12/16/2022]
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Zahir T, Nomura H, Guo XD, Kim H, Tator C, Morshead C, Shoichet M. Bioengineering Neural Stem/Progenitor Cell-Coated Tubes for Spinal Cord Injury Repair. Cell Transplant 2008; 17:245-54. [DOI: 10.3727/096368908784153887] [Citation(s) in RCA: 69] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
The aim of this study was to understand the survival and differentiation of neural stem/progenitor cells (NSPCs) cultured on chitosan matrices in vivo in a complete transection model of spinal cord injury. NSPCs were isolated from the subependyma of lateral ventricles of adult GFP transgenic rat forebrains. The GFP-positive neurospheres were seeded onto the inner lumen of chitosan tubes to generate multicellular sheets ex vivo. These bioengineered neurosphere tubes were implanted into a completely transected spinal cord and assessed after 5 weeks for survival and differentiation. The in vivo study showed excellent survival of NSPCs, as well as differentiation into astrocytes and oligodendrocytes. Importantly, host neurons were identified in the tissue bridge that formed within the chitosan tubes and bridged the transected cord stumps. The excellent in vivo survival of the NSPCs coupled with their differentiation and maintenance of host neurons in the regenerated tissue bridge demonstrates the promise of the chitosan tubes for stem cell delivery and tissue regeneration.
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Affiliation(s)
- Tasneem Zahir
- Terrence Donnelly Centre for Cellular & Biomolecular Research, University of Toronto, Toronto, Canada
- Department of Chemical Engineering & Applied Chemistry, University of Toronto, Toronto, Canada
| | - Hiroshi Nomura
- Toronto Western Research Institute, Toronto Western Hospital, Toronto, Canada
| | - Xiao Dong Guo
- Toronto Western Research Institute, Toronto Western Hospital, Toronto, Canada
| | - Howard Kim
- Terrence Donnelly Centre for Cellular & Biomolecular Research, University of Toronto, Toronto, Canada
| | - Charles Tator
- Toronto Western Research Institute, Toronto Western Hospital, Toronto, Canada
- Department of Surgery, University of Toronto, Toronto, Canada
| | - Cindi Morshead
- Terrence Donnelly Centre for Cellular & Biomolecular Research, University of Toronto, Toronto, Canada
- Department of Surgery, University of Toronto, Toronto, Canada
| | - Molly Shoichet
- Terrence Donnelly Centre for Cellular & Biomolecular Research, University of Toronto, Toronto, Canada
- Department of Chemical Engineering & Applied Chemistry, University of Toronto, Toronto, Canada
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Hejcl A, Urdzikova L, Sedy J, Lesny P, Pradny M, Michalek J, Burian M, Hajek M, Zamecnik J, Jendelova P, Sykova E. Acute and delayed implantation of positively charged 2-hydroxyethyl methacrylate scaffolds in spinal cord injury in the rat. J Neurosurg Spine 2008; 8:67-73. [PMID: 18173349 DOI: 10.3171/spi-08/01/067] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
OBJECT Hydrogels are nontoxic, chemically inert synthetic polymers with a high water content and large surface area that provide mechanical support for cells and axons when implanted into spinal cord tissue. METHODS Macroporous hydrogels based on 2-hydroxyethyl methacrylate (HEMA) were prepared by radical copolymerization of monomers in the presence of fractionated NaCl particles. Male Wistar rats underwent complete spinal cord transection at the T-9 level. To bridge the lesion, positively charged HEMA hydrogels were implanted either immediately or 1 week after spinal cord transection; control animals were left untreated. Histological evaluation was performed 3 months after spinal cord transection to measure the volume of the pseudocyst cavities and the ingrowth of tissue elements into the hydrogels. RESULTS The hydrogel implants adhered well to the spinal cord tissue. Histological evaluation showed ingrowth of connective tissue elements, blood vessels, neurofilaments, and Schwann cells into the hydrogels. Morphometric analysis of lesions showed a statistically significant reduction in pseudocyst volume in the treated animals compared with controls and in the delayed treatment group compared with the immediate treatment group (p < 0.001 and p < 0.05, respectively). CONCLUSIONS Positively charged HEMA hydrogels can bridge a posttraumatic spinal cord cavity and provide a scaffold for the ingrowth of regenerating axons. The results indicate that delayed implantation can be more effective than immediate reconstructive surgery.
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Affiliation(s)
- Ales Hejcl
- Institute of Experimental Medicine, Academy of Sciences of the Czech Republic, Czech Republic.
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Richter MW, Roskams AJ. Olfactory ensheathing cell transplantation following spinal cord injury: Hype or hope? Exp Neurol 2008; 209:353-67. [PMID: 17643431 DOI: 10.1016/j.expneurol.2007.06.011] [Citation(s) in RCA: 101] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2007] [Accepted: 06/11/2007] [Indexed: 11/27/2022]
Abstract
Olfactory ensheathing cells (OECs) are unique glia found only in the olfactory system that retain exceptional plasticity, and support olfactory neurogenesis and the re-targeting across the PNS:CNS boundary in the olfactory system. Because they are also relatively accessible in an adult rodent or human, OECs have become a prime candidate for cell-mediated repair following a variety of CNS lesions. A number of different labs across the world have applied OECs prepared in many different ways in several different acute and chronic models of rodent SCI, some of which have suggested surprising degrees of functional recovery. OECs can stimulate tissue sparing and neuroprotection, enhance outgrowth of both intact and lesioned axons (to different degrees), activate angiogenesis, change the response status of endogenous glia after lesion and remyelinate axons after a range of demyelinating insults. Their ability to stimulate regeneration in specific tracts is, however, limited. Despite this, the ongoing clinical use of cell preparations containing OECs has proceeded as a therapeutic approach for human spinal cord injury (SCI). Here, we review the current status of OEC research in SCI, and focus on potential mechanisms for OECs in the SCI repair response that may help to explain the biological reasons underlying the wide variation of results obtained in this promising, yet contentious, field.
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Affiliation(s)
- Miranda W Richter
- Department of Zoology and Medicine, University of British Columbia, Vancouver, BC, Canada
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Au E, Richter MW, Vincent AJ, Tetzlaff W, Aebersold R, Sage EH, Roskams AJ. SPARC from olfactory ensheathing cells stimulates Schwann cells to promote neurite outgrowth and enhances spinal cord repair. J Neurosci 2007; 27:7208-21. [PMID: 17611274 PMCID: PMC6794587 DOI: 10.1523/jneurosci.0509-07.2007] [Citation(s) in RCA: 108] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2007] [Revised: 04/23/2007] [Accepted: 05/17/2007] [Indexed: 11/21/2022] Open
Abstract
Olfactory ensheathing cells (OECs) transplanted into the lesioned CNS can stimulate reportedly different degrees of regeneration, remyelination, and functional recovery, but little is known about the mechanisms OECs may use to stimulate endogenous repair. Here, we used a functional proteomic approach, isotope-coded affinity tagging and mass spectrometry, to identify active components of the OEC secreteome that differentially stimulate outgrowth. SPARC (secreted protein acidic rich in cysteine) (osteonectin) was identified as an OEC-derived matricellular protein that can indirectly enhance the ability of Schwann cells to stimulate dorsal root ganglion outgrowth in vitro. SPARC stimulates Schwann cell-mediated outgrowth by cooperative signal with laminin-1 and transforming growth factor beta. Furthermore, when SPARC-null OECs were transplanted into lesioned rat spinal cord, the absence of OEC-secreted SPARC results in an attenuation of outgrowth of specific subsets of sensory and supraspinal axons and changes the pattern of macrophage infiltration in response to the transplanted cells. These data provide the first evidence for a role for SPARC in modulating different aspects of CNS repair and indicate that SPARC can change the activation state of endogenous Schwann cells, resulting in the promotion of outgrowth in vitro, and in vivo.
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Affiliation(s)
- Edmund Au
- Department of Zoology, Life Sciences Institute and
| | | | | | - Wolfram Tetzlaff
- Department of Zoology, Life Sciences Institute and
- International Collaboration on Repair Discoveries, University of British Columbia, Vancouver, British Columbia, Canada V6T 1Z3
| | - Ruedi Aebersold
- Institute for Systems Biology, Seattle, Washington 98103
- Molecular Systems Biology, Swiss Federal Institute of Technology of Zurich, CH-8092 Zurich, Switzerland, and
| | - E. Helene Sage
- Hope Heart Program, Benaroya Research Institute at Virginia Mason, Seattle, Washington 98101
| | - A. Jane Roskams
- Department of Zoology, Life Sciences Institute and
- International Collaboration on Repair Discoveries, University of British Columbia, Vancouver, British Columbia, Canada V6T 1Z3
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Dinh P, Bhatia N, Rasouli A, Suryadevara S, Cahill K, Gupta R. Transplantation of preconditioned Schwann cells following hemisection spinal cord injury. Spine (Phila Pa 1976) 2007; 32:943-9. [PMID: 17450067 DOI: 10.1097/01.brs.0000261408.61303.77] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
STUDY DESIGN Chronically compressed sciatic nerve segments were transplanted to hemisected spinal cord injured rats. Histologic evaluation and behavior functional outcomes were tested after 6 weeks following surgery. OBJECTIVE To evaluate the outcome of preconditioned peripheral nerves as a permissive environment in axonal regeneration of the injured spinal cord. SUMMARY OF BACKGROUND DATA Schwann cells have been used to facilitate a permissive environment for the injured spinal cord to regenerate. Previous experiments have shown compressive mechanical stress to be important in stimulating the regenerative behavior of Schwann cells. Transplantation of highly permissive Schwann cell-enriched peripheral nerve grafts may enhance regeneration in spinal cord injury. METHODS Adult Sprague-Dawley rats (n = 24) were used to create a hemisection injury of the spinal cord. At 1-week postinjury creation, the spinal cords were reexposed for all animals. Peripheral nerve grafts were obtained from rat sciatic nerve, either untreated or subjected to mechanical compression for 2 weeks with nonconstrictive tubing. Transplantation of grafts was performed after a resection of the glial scar. Functional outcome was measured using the Basso, Beattie, Bresnahan Locomotor Rating Score and footprint analysis. Tract tracing of descending and ascending spinal cord tracts was performed at 6 weeks after surgery for histologic evaluation of axonal regeneration. RESULTS Preconditioned transplants had significantly higher Basso, Beattie, Bresnahan Scores versus hemisection alone in the late postoperative period (P < 0.05). They also had significantly less foot exorotation and base of support when compared to nonconditioned transplants. Histologic analysis showed increased regeneration at lesional sites for preconditioned transplants versus control group (P < 0.05). CONCLUSIONS Functional recovery after hemisection injury improved significantly in the late postoperative period with transplantation of preconditioned peripheral nerve. Preconditioned grafts also exhibit sustained axonal regeneration at and past the lesional site in histologic analysis. Further investigation with later time points is warranted.
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Affiliation(s)
- Paul Dinh
- University of California, Irvine, CA, USA
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Ito D, Ibanez C, Ogawa H, Franklin RJM, Jeffery ND. Comparison of cell populations derived from canine olfactory bulb and olfactory mucosal cultures. Am J Vet Res 2007; 67:1050-6. [PMID: 16740101 DOI: 10.2460/ajvr.67.6.1050] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
OBJECTIVE To evaluate the numbers and proportions of olfactory ensheathing cells (OECs) in cell cultures derived from the olfactory bulb (OB) and olfactory mucosa of dogs. ANIMALS 7 dogs. PROCEDURES OB tissue and olfactory mucosa from the nasal cavity and frontal sinus were obtained from euthanatized dogs and prepared for cell culture. At 7, 14, and 21 days of culture in vitro, numbers and proportions of OECs, astrocytes, and fibroblasts were determined via immunocytochemistry. Antibody against the low-affinity nerve growth factor receptor p75 was used to identify OECs, antibody against glial fibrillary acidic protein was used to identify astrocytes, and antibody against fibronectin was used to identify fibroblasts. RESULTS Cultured OECs derived from the olfactory mucosa of the nasal cavity and frontal sinus had similar characteristics. However, whereas OECs in the OB cell cultures constituted approximately 50% of the cells at 7 days and approximately 75% at 21 days the proportion of OECs in cultures derived from both mucosal types was much lower, with approximately 40% OECs at 7 days and approximately 25% at 21 days. Analysis of OEC numbers revealed that these changes were accompanied by corresponding decreases and increases in the population of cells with fibronectin receptors. CONCLUSIONS AND CLINICAL RELEVANCE Although olfactory mucosal cell cultures yielded a sufficient number of OECs for spinal cord transplantation procedures in dogs, modification of culture conditions would be required to ensure that the derived cell population contained a sufficient proportion of OECs.
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Affiliation(s)
- Daisuke Ito
- Department of Veterinary Medicine, University of Cambridge, Cambridge CB3 0ES, UK
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Oudega M. Schwann cell and olfactory ensheathing cell implantation for repair of the contused spinal cord. Acta Physiol (Oxf) 2007; 189:181-9. [PMID: 17250568 DOI: 10.1111/j.1748-1716.2006.01658.x] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
A contusion injury to the spinal cord results in impaired neurological functions due to neuronal death, and axonal damage and demyelination. In time, a fluid-filled cyst forms at the site of the initial impact. There are no effective endogenous repair mechanisms and, consequently, injury-induced functional deficits are permanent. One aspect of spinal cord repair is that severed descending and ascending axons need to regenerate beyond the site of injury towards the denervated spinal regions where they can become part of axonal circuits involved in motor and sensory function. Implantation of cells into the injured cord has been studied extensively as a means to promote axonal regeneration in the injured spinal cord. Depending on the overall damage, different cell types may be appropriate in different types of injury. To accomplish axonal regeneration in the contused spinal cord, the strengths and limitations of two glial cell types in particular will be discussed; Schwann cells and olfactory ensheathing cells. It is known that with these implants, axonal regeneration is frustrated by the presence of a glial scar surrounding the contused area. I will review current approaches aimed at overcoming this axonal growth inhibitory scar. Future studies need to focus on identifying interventions that, in combination with cellular implants, will elicit substantial axonal growth beyond the contusion injury, which may then be the basis for biologically significant functional recovery.
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Affiliation(s)
- M Oudega
- International Center for Spinal Cord Injury, Kennedy Krieger Institute and the Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA.
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Pastrana E, Moreno-Flores MT, Avila J, Wandosell F, Minichiello L, Diaz-Nido J. BDNF production by olfactory ensheathing cells contributes to axonal regeneration of cultured adult CNS neurons. Neurochem Int 2006; 50:491-8. [PMID: 17157963 DOI: 10.1016/j.neuint.2006.10.004] [Citation(s) in RCA: 56] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2006] [Revised: 10/05/2006] [Accepted: 10/10/2006] [Indexed: 01/15/2023]
Abstract
Olfactory ensheathing cells (OECs) are the main glial cell type that populates mammalian olfactory nerves. These cells have a great capacity to promote the regeneration of axons when transplanted into the injured adult mammalian CNS. However, little is still known about the molecular mechanisms they employ in mediating such a task. Brain-derived neurotrophic factor (BDNF) was identified as a candidate molecule in a genomic study that compared three functionally different OEC populations: Early passage OECs (OEC Ep), Late passage OECs (OEC Lp) and the OEC cell line TEG3 [Pastrana, E., Moreno-Flores, M.T., Gurzov, E.N., Avila, J., Wandosell, F., Diaz-Nido, J., 2006. Genes associated with adult axon regeneration promoted by olfactory ensheathing cells: a new role for matrix metalloproteinase 2. J. Neurosci. 26, 5347-5359]. We have here set out to determine the role played by BDNF in the stimulation of axon outgrowth by OECs. We compared the extracellular BDNF levels in the three OEC populations and show that it is produced in significant amounts by the OECs that can stimulate axon regeneration in adult retinal neurons (OEC Ep and TEG3) but it is absent from the extracellular medium of OEC Lp cells which lack this capacity. Blocking BDNF signalling impaired axonal regeneration of adult retinal neurons co-cultured with TEG3 cells and adding BDNF increased the proportion of adult neurons that regenerate their axons on OEC Lp monolayers. Combining BDNF with other extracellular proteins such as Matrix Metalloproteinase 2 (MMP2) further augmented this effect. This study shows that BDNF production by OECs plays a direct role in the promotion of axon regeneration of adult CNS neurons.
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Affiliation(s)
- Erika Pastrana
- Centro de Biologia Molecular Severo Ochoa, Universidad Autonoma de Madrid, Madrid, Spain
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Rasouli A, Bhatia N, Suryadevara S, Cahill K, Gupta R. Transplantation of preconditioned schwann cells in peripheral nerve grafts after contusion in the adult spinal cord. Improvement of recovery in a rat model. J Bone Joint Surg Am 2006; 88:2400-10. [PMID: 17079397 DOI: 10.2106/jbjs.e.01424] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
BACKGROUND Recovery after injury to the peripheral nervous system is based on the pro-regenerative relationship between axons and the extracellular matrix, a relationship established by Schwann cells. As mechanical conditioning of Schwann cells has been shown to stimulate their regenerative behavior, we sought to determine whether transplantation of these cells to the central nervous system (i.e., the spinal cord), with its limited regenerative capacity after injury, would improve axonal regeneration and functional recovery. METHODS A moderate contusion injury of the spinal cord was created with a force-directed impactor in forty-eight adult Sprague-Dawley rats, and, at one week postinjury, the spinal cords were reexposed in all animals. In twenty-four of these animals, peripheral nerve grafts with Schwann cells that had been obtained from the sciatic nerves of donor animals, and had been either untreated or subjected to mechanical conditioning, were transplanted to the contused area of the cords following resection of the glial scar. Another group of animals was treated with glial scar excision only, and a fourth group had the contusion injury but neither glial excision nor transplantation. Scores according to the Basso, Beattie, Bresnahan (BBB) Locomotor Rating Scale were assigned preoperatively and weekly thereafter. Tract tracing of descending and ascending spinal cord tracts was performed at six weeks postoperatively for quantitative histological evaluation of axonal regeneration. RESULTS While the recovery following glial scar excision without peripheral nerve transplantation was significantly worse than the recovery in the other groups, both transplantation groups had significantly higher BBB scores than the controls (no transplantation) in the early postoperative period (p < 0.05). Moreover, histological analysis showed markedly increased axonal regeneration at the lesional sites in the animals treated with the mechanically conditioned grafts than in the other groups (p < 0.05). CONCLUSIONS Functional recovery after spinal cord contusion improved following glial scar excision with transplantation of Schwann cells in peripheral nerve grafts to the contusion areas. Although recovery did not differ significantly between the transplantation groups, only the preconditioned grafts led to axonal regeneration at and past the lesional site. These grafts may further enhance functional recovery as the descending tracts eventually reach their target end-organs.
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Affiliation(s)
- Alexandre Rasouli
- University of California, Irvine, 2226 Gillespie Neuroscience Research Facility, Irvine, CA 92697, USA
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Abstract
During the past few years, several approaches to spinal-cord repair have been successfully established in animal models. For their use in trials of spinal-cord injury (SCI) in human beings, specific difficulties that affect the success of clinical trials have to be recognised. First, transection of the spinal cord is commonly applied in animal models, whereas contusion, which generally leads to injury in two to three segments, represents the typical injury mechanism in human beings. Second, the quadrupedal organisation of locomotion in animals and the more complex autonomic functions in human beings, challenge translation of animal behaviour into recovery from SCI in people. Third, the extensive damage of motor neurons and roots associated with spinal-cord contusion is not addressed in current translational studies. This damage has direct implications for rehabilitation strategies and functional outcome. Fourth, there is increasing evidence for a degradation of neuronal function below the level of the lesion in chronic complete SCI. The relevance of this degradation for a regeneration-inducing treatment needs to be investigated. Fifth, the prerequisites to enable appropriate reconnection of regenerating tract fibres in a postacute stage have still to be established.
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Affiliation(s)
- Volker Dietz
- Spinal Cord Injury Centre, University Hospital Balgrist, Zürich, Switzerland.
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Nomura H, Katayama Y, Shoichet MS, Tator CH. COMPLETE SPINAL CORD TRANSECTION TREATEDBY IMPLANTATION OF A REINFORCED SYNTHETIC HYDROGEL CHANNEL RESULTS IN SYRINGOMYELIA AND CAUDAL MIGRATION OF THE ROSTRAL STUMP. Neurosurgery 2006. [DOI: 10.1227/01.neu.0000243297.69189.f8] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
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Nomura H, Katayama Y, Shoichet MS, Tator CH. Complete Spinal Cord Transection Treatedby Implantation of a Reinforced Synthetic Hydrogel Channel Results in Syringomyelia and Caudal Migration of the Rostral Stump. Neurosurgery 2006; 59:183-92; discussion 183-92. [PMID: 16823315 DOI: 10.1227/01.neu.0000219859.35349.ef] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
OBJECTIVE Previously, we reported that synthetic poly(2-hydroxyethyl methacrylate-co-methyl methacrylate) (PHEMA-MMA) channels promoted regeneration of a small number of axons from brainstem motor nuclei yet provided limited functional recovery after complete spinal cord transection at T8 in rats. However, we found that these modulus channels partially collapsed over time. Therefore, we synthesized coil-reinforced PHEMA or PHEMA-MMA channels with greater elastic moduli and introduced a new spinal fixation technique to prevent collapse. We also assessed axonal regeneration within the new channels containing a cocktail of autologous peripheral nerve grafts, fibrin matrix, and acidic fibroblast growth factor. METHODS After spinal cord transection, rats were divided into six groups: Groups 1 and 2 had either a PHEMA or PHEMA-MMA reinforced channel implanted between the stumps of the transected spinal cord with the cocktail; Groups 3 and 4 had either an unfilled reinforced PHEMA or PHEMA-MMA channel similarly implanted; Group 5 had an spinal cord transection without channel implanted, and Group 6 underwent the identical procedure to Group 1, but rats were sacrificed by 8 weeks for early histological assessment. Groups 1 to 5 were sacrificed at 18 weeks. RESULTS There was no channel collapse at any time. However, there was no improvement in axonal regeneration or functional recovery among Groups 1 to 4 because of the unexpected development of syringomyelia and caudal migration of the rostral stump. Functional recovery was better in Groups 1 to 4 compared with Group 5 (P < 0.05). CONCLUSION The use of channels to enhance regeneration of axons is promising; however, improvement of the design of the channels is required.
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Affiliation(s)
- Hiroshi Nomura
- Toronto Western Research Institute, Toronto Western Hospital,Toronto, Canada
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