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Neishaboori AM, Tavallaei MJ, Toloui A, Ahmadzadeh K, Alavi SNR, Lauran M, Hosseini M, Yousefifard M. Effects of Epothilone Administration on Locomotion Recovery after Spinal Cord Injury: A Systematic Review of Animal Studies. Asian Spine J 2023; 17:761-769. [PMID: 37062538 PMCID: PMC10460658 DOI: 10.31616/asj.2022.0005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/13/2022] [Revised: 06/05/2022] [Accepted: 06/30/2022] [Indexed: 04/18/2023] Open
Abstract
This is a systematic review and meta-analysis of existing evidence regarding the possible effects of epothilones on spinal cord injury (SCI). This study aimed to investigate the possible effects of epothilone administration on locomotion recovery in animal models of SCI. Despite increasing rates of SCI and its burden on populations, no consensus has been reached about the possible treatment modality for SCI. Meanwhile, low-dose epothilones have been reported to have positive effects on SCI outcomes. Electronic databases of Web of Science, Scopus, Embase, and Medline were searched using keywords related to epothilones and SCI until the end of 2020. Two researchers screened the articles, and extracted data were analyzed using STATA ver. 14.0. Final results are reported as a standardized mean difference (SMD) with a 95% confidence interval (CI). After the screening, five studies were included in the analysis. Rats were used in all the studies. Two types of epothilones were used via intraperitoneal injection and were shown to have positive effects on the motor outcomes of samples with SCI (SMD, 0.87; 95% CI, 0.51 to 1.23; p =0.71). Although a slightly better effect was observed when using epothilone B, the difference was not significant (coefficient, -0.50; 95% CI, -1.52 to 0.52; p =0.246). The results of this study suggest that epothilones have positive effects on the improvement of motor function in rats, when administered intraperitoneally until a maximum of 1 day after SCI. However, current evidence regarding the matter is still scarce.
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Affiliation(s)
| | | | - Amirmohammad Toloui
- Physiology Research Center, Iran University of Medical Sciences, Tehran, Iran
| | - Koohyar Ahmadzadeh
- Physiology Research Center, Iran University of Medical Sciences, Tehran, Iran
| | | | - Martin Lauran
- GKT School of Medical Education, King’s College London, London, UK
| | - Mostafa Hosseini
- Department of Epidemiology and Biostatistics, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran
| | - Mahmoud Yousefifard
- Physiology Research Center, Iran University of Medical Sciences, Tehran, Iran
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Davleeva MA, Garifulin RR, Bashirov FV, Izmailov AA, Nurullin LF, Salafutdinov II, Gatina DZ, Shcherbinin DN, Lysenko AA, Tutykhina IL, Shmarov MM, Islamov RR. Molecular and cellular changes in the post-traumatic spinal cord remodeling after autoinfusion of a genetically-enriched leucoconcentrate in a mini-pig model. Neural Regen Res 2023; 18:1505-1511. [PMID: 36571355 PMCID: PMC10075125 DOI: 10.4103/1673-5374.360241] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
Post-traumatic spinal cord remodeling includes both degenerating and regenerating processes, which affect the potency of the functional recovery after spinal cord injury (SCI). Gene therapy for spinal cord injury is proposed as a promising therapeutic strategy to induce positive changes in remodeling of the affected neural tissue. In our previous studies for delivering the therapeutic genes at the site of spinal cord injury, we developed a new approach using an autologous leucoconcentrate transduced ex vivo with chimeric adenoviruses (Ad5/35) carrying recombinant cDNA. In the present study, the efficacy of the intravenous infusion of an autologous genetically-enriched leucoconcentrate simultaneously producing recombinant vascular endothelial growth factor (VEGF), glial cell line-derived neurotrophic factor (GDNF), and neural cell adhesion molecule (NCAM) was evaluated with regard to the molecular and cellular changes in remodeling of the spinal cord tissue at the site of damage in a model of mini-pigs with moderate spinal cord injury. Experimental animals were randomly divided into two groups of 4 pigs each: the therapeutic (infused with the leucoconcentrate simultaneously transduced with a combination of the three chimeric adenoviral vectors Ad5/35-VEGF165, Ad5/35-GDNF, and Ad5/35-NCAM1) and control groups (infused with intact leucoconcentrate). The morphometric and immunofluorescence analysis of the spinal cord regeneration in the rostral and caudal segments according to the epicenter of the injury in the treated animals compared to the control mini-pigs showed: (1) higher sparing of the grey matter and increased survivability of the spinal cord cells (lower number of Caspase-3-positive cells and decreased expression of Hsp27); (2) recovery of synaptophysin expression; (3) prevention of astrogliosis (lower area of glial fibrillary acidic protein-positive astrocytes and ionized calcium binding adaptor molecule 1-positive microglial cells); (4) higher growth rates of regenerating βIII-tubulin-positive axons accompanied by a higher number of oligodendrocyte transcription factor 2-positive oligodendroglial cells in the lateral corticospinal tract region. These results revealed the efficacy of intravenous infusion of the autologous genetically-enriched leucoconcentrate producing recombinant VEGF, GDNF, and NCAM in the acute phase of spinal cord injury on the positive changes in the post-traumatic remodeling nervous tissue at the site of direct injury. Our data provide a solid platform for a new ex vivo gene therapy for spinal cord injury and will facilitate further translation of regenerative therapies in clinical neurology.
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Affiliation(s)
| | | | | | | | - Leniz Faritovich Nurullin
- Department of Histology, Cytology and Embryology, Kazan State Medical University; Kazan Institute of Biochemistry and Biophysics, Federal Research Center of Kazan Scientific Center of Russian Academy of Sciences, Kazan, Russia
| | - Ilnur Ildusovich Salafutdinov
- Department of Histology, Cytology and Embryology, Kazan State Medical University; Institute of Fundamental Medicine and Biology, Kazan Federal University, Kazan, Russia
| | | | - Dmitrij Nikolaevich Shcherbinin
- The National Research Center for Epidemiology and Microbiology named after Honorary Academician N.F. Gamaleya of the Ministry of Health of the Russian Federation, Moscow, Russia
| | - Andrei Aleksandrovich Lysenko
- The National Research Center for Epidemiology and Microbiology named after Honorary Academician N.F. Gamaleya of the Ministry of Health of the Russian Federation, Moscow, Russia
| | - Irina Leonidovna Tutykhina
- The National Research Center for Epidemiology and Microbiology named after Honorary Academician N.F. Gamaleya of the Ministry of Health of the Russian Federation, Moscow, Russia
| | - Maksim Mikhailovich Shmarov
- The National Research Center for Epidemiology and Microbiology named after Honorary Academician N.F. Gamaleya of the Ministry of Health of the Russian Federation, Moscow, Russia
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Schading S, David G, Max Emmenegger T, Achim C, Thompson A, Weiskopf N, Curt A, Freund P. Dynamics of progressive degeneration of major spinal pathways following spinal cord injury: A longitudinal study. Neuroimage Clin 2023; 37:103339. [PMID: 36758456 PMCID: PMC9939725 DOI: 10.1016/j.nicl.2023.103339] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2022] [Revised: 12/23/2022] [Accepted: 01/26/2023] [Indexed: 02/04/2023]
Abstract
BACKGROUND Following spinal cord injury (SCI), disease processes spread gradually along the spinal cord forming a spatial gradient with most pronounced changes located at the lesion site. However, the dynamics of this gradient in SCI patients is not established. OBJECTIVE This study tracks the spatiotemporal dynamics of remote anterograde and retrograde spinal tract degeneration in the upper cervical cord following SCI over two years utilizing quantitative MRI. METHODS Twenty-three acute SCI patients (11 paraplegics, 12 tetraplegics) and 21 healthy controls were scanned with a T1-weighted sequence for volumetry and a FLASH sequence for myelin-sensitive magnetization transfer saturation (MTsat) of the upper cervical cord. We estimated myelin content from MTsat maps within the corticospinal tracts (CST) and dorsal columns (DC) and measured spinal cord atrophy by means of left-right width (LRW) and anterior-posterior width (APW) on the T1-weighted images across cervical levels C1-C3. MTsat in the CST and LRW were considered proxies for retrograde degeneration, while MTsat in the DC and APW provided evidence for anterograde degeneration, respectively. Using regression models, we compared the temporal and spatial trajectories of these MRI readouts between tetraplegics, paraplegics, and controls over a 2-year period and assessed their associations with clinical improvement. RESULTS Linear rates and absolute differences in myelin-sensitive MTsat indicated retrograde and anterograde neurodegeneration in the CST and DC, respectively. Changes in MTsat within the CST and in LRW progressively developed over time forming a gradient towards lower cervical levels by 2 years after injury, especially in tetraplegics (change per cervical level in MTsat: -0.247 p.u./level, p = 0.034; in LRW: -0.323 mm/level, p = 0.024). MTsat within the DC was already decreased at cervical levels C1-C3 at baseline (1.5 months after injury) in both tetra- and paraplegics, while linear decreases in APW over time were similar across C1-C3, preserving the spatial gradient. The relative improvement in light touch score was associated with MTsat within the DC at baseline (rs = 0.575, p = 0.014). CONCLUSION Rostral and remote to the injury, the CST and DC show ongoing structural changes, indicative of myelin reductions and atrophy within 2 years after SCI. While anterograde degeneration in the DC was already detectable uniformly at C1-C3 early following SCI, retrograde degeneration in the CST developed over time revealing specific spatial and temporal neurodegenerative gradients. Disentangling and quantifying such dynamic pathological processes may provide biomarkers for regenerative and remyelinating therapies along entire spinal pathways.
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Affiliation(s)
- Simon Schading
- Spinal Cord Injury Center, Balgrist University Hospital, University of Zurich, Zurich, Switzerland
| | - Gergely David
- Spinal Cord Injury Center, Balgrist University Hospital, University of Zurich, Zurich, Switzerland
| | - Tim Max Emmenegger
- Spinal Cord Injury Center, Balgrist University Hospital, University of Zurich, Zurich, Switzerland
| | - Cristian Achim
- Spinal Cord Injury Center, Balgrist University Hospital, University of Zurich, Zurich, Switzerland
| | - Alan Thompson
- Department of Brain Repair and Rehabilitation, UCL Queen Square Institute of Neurology, University College London, London, UK
| | - Nikolaus Weiskopf
- Department of Neurophysics, Max Planck Institute for Human Cognitive and Brain Sciences, Leipzig, Germany; Felix Bloch Institute for Solid State Physics, Faculty of Physics and Earth Sciences, Leipzig University, Leipzig, Germany
| | - Armin Curt
- Spinal Cord Injury Center, Balgrist University Hospital, University of Zurich, Zurich, Switzerland
| | - Patrick Freund
- Spinal Cord Injury Center, Balgrist University Hospital, University of Zurich, Zurich, Switzerland; Department of Neurophysics, Max Planck Institute for Human Cognitive and Brain Sciences, Leipzig, Germany; Wellcome Trust Centre for Neuroimaging, UCL Queen Square Institute of Neurology, University College London, London, UK.
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BDNF Spinal Overexpression after Spinal Cord Injury Partially Protects Soleus Neuromuscular Junction from Disintegration, Increasing VAChT and AChE Transcripts in Soleus but Not Tibialis Anterior Motoneurons. Biomedicines 2022; 10:biomedicines10112851. [DOI: 10.3390/biomedicines10112851] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2022] [Revised: 10/20/2022] [Accepted: 11/04/2022] [Indexed: 11/09/2022] Open
Abstract
After spinal cord transection (SCT) the interaction between motoneurons (MNs) and muscle is impaired, due to reorganization of the spinal network after a loss of supraspinal inputs. Rats subjected to SCT, treated with intraspinal injection of a AAV-BDNF (brain-derived neurotrophic factor) construct, partially regained the ability to walk. The central effects of this treatment have been identified, but its impact at the neuromuscular junction (NMJ) has not been characterized. Here, we compared the ability of NMJ pre- and postsynaptic machinery in the ankle extensor (Sol) and flexor (TA) muscles to respond to intraspinal AAV-BDNF after SCT. The gene expression of cholinergic molecules (VAChT, ChAT, AChE, nAChR, mAChR) was investigated in tracer-identified, microdissected MN perikarya, and in muscle fibers with the use of qPCR. In the NMJs, a distribution of VAChT, nAChR and Schwann cells was studied by immunofluorescence, and of synaptic vesicles and membrane active zones by electron microscopy. We showed partial protection of the Sol NMJs from disintegration, and upregulation of the VAChT and AChE transcripts in the Sol, but not the TA MNs after spinal enrichment with BDNF. We propose that the observed discrepancy in response to BDNF treatment is an effect of difference in the TrkB expression setting BDNF responsiveness, and of BDNF demands in Sol and TA muscles.
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Slater PG, Domínguez-Romero ME, Villarreal M, Eisner V, Larraín J. Mitochondrial function in spinal cord injury and regeneration. Cell Mol Life Sci 2022; 79:239. [PMID: 35416520 PMCID: PMC11072423 DOI: 10.1007/s00018-022-04261-x] [Citation(s) in RCA: 21] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2021] [Revised: 03/16/2022] [Accepted: 03/17/2022] [Indexed: 12/21/2022]
Abstract
Many people around the world suffer from some form of paralysis caused by spinal cord injury (SCI), which has an impact on quality and life expectancy. The spinal cord is part of the central nervous system (CNS), which in mammals is unable to regenerate, and to date, there is a lack of full functional recovery therapies for SCI. These injuries start with a rapid and mechanical insult, followed by a secondary phase leading progressively to greater damage. This secondary phase can be potentially modifiable through targeted therapies. The growing literature, derived from mammalian and regenerative model studies, supports a leading role for mitochondria in every cellular response after SCI: mitochondrial dysfunction is the common event of different triggers leading to cell death, cellular metabolism regulates the immune response, mitochondrial number and localization correlate with axon regenerative capacity, while mitochondrial abundance and substrate utilization regulate neural stem progenitor cells self-renewal and differentiation. Herein, we present a comprehensive review of the cellular responses during the secondary phase of SCI, the mitochondrial contribution to each of them, as well as evidence of mitochondrial involvement in spinal cord regeneration, suggesting that a more in-depth study of mitochondrial function and regulation is needed to identify potential targets for SCI therapeutic intervention.
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Affiliation(s)
- Paula G Slater
- Center for Aging and Regeneration, Departamento de Biología Celular Y Molecular, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Alameda 340, 8331150, Santiago, Chile.
| | - Miguel E Domínguez-Romero
- Center for Aging and Regeneration, Departamento de Biología Celular Y Molecular, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Alameda 340, 8331150, Santiago, Chile
| | - Maximiliano Villarreal
- Center for Aging and Regeneration, Departamento de Biología Celular Y Molecular, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Alameda 340, 8331150, Santiago, Chile
| | - Verónica Eisner
- Center for Aging and Regeneration, Departamento de Biología Celular Y Molecular, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Alameda 340, 8331150, Santiago, Chile
- Departamento de Biología Celular y Molecular, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Alameda 340, 8331150, Santiago, Chile
| | - Juan Larraín
- Center for Aging and Regeneration, Departamento de Biología Celular Y Molecular, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Alameda 340, 8331150, Santiago, Chile
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Kiang L, Woodington B, Carnicer-Lombarte A, Malliaras G, Barone DG. Spinal cord bioelectronic interfaces: opportunities in neural recording and clinical challenges. J Neural Eng 2022; 19. [PMID: 35320780 DOI: 10.1088/1741-2552/ac605f] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2021] [Accepted: 03/23/2022] [Indexed: 11/11/2022]
Abstract
Bioelectronic stimulation of the spinal cord has demonstrated significant progress in restoration of motor function in spinal cord injury (SCI). The proximal, uninjured spinal cord presents a viable target for the recording and generation of control signals to drive targeted stimulation. Signals have been directly recorded from the spinal cord in behaving animals and correlated with limb kinematics. Advances in flexible materials, electrode impedance and signal analysis will allow SCR to be used in next-generation neuroprosthetics. In this review, we summarize the technological advances enabling progress in SCR and describe systematically the clinical challenges facing spinal cord bioelectronic interfaces and potential solutions, from device manufacture, surgical implantation to chronic effects of foreign body reaction and stress-strain mismatches between electrodes and neural tissue. Finally, we establish our vision of bi-directional closed-loop spinal cord bioelectronic bypass interfaces that enable the communication of disrupted sensory signals and restoration of motor function in SCI.
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Affiliation(s)
- Lei Kiang
- Orthopaedic Surgery, Singapore General Hospital, Outram Road, Singapore, Singapore, 169608, SINGAPORE
| | - Ben Woodington
- Department of Engineering, University of Cambridge, Electrical Engineering Division, 9 JJ Thomson Ave, Cambridge, Cambridge, CB2 1TN, UNITED KINGDOM OF GREAT BRITAIN AND NORTHERN IRELAND
| | - Alejandro Carnicer-Lombarte
- Clinical Neurosciences, University of Cambridge, Bioelectronics Laboratory, Cambridge, CB2 0PY, UNITED KINGDOM OF GREAT BRITAIN AND NORTHERN IRELAND
| | - George Malliaras
- University of Cambridge, University of Cambridge, Cambridge, CB2 1TN, UNITED KINGDOM OF GREAT BRITAIN AND NORTHERN IRELAND
| | - Damiano G Barone
- Department of Engineering, University of Cambridge, Electrical Engineering Division, 9 JJ Thomson Ave, Cambridge, Cambridge, Cambridgeshire, CB2 1TN, UNITED KINGDOM OF GREAT BRITAIN AND NORTHERN IRELAND
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Ren X, Zhang W, Mo J, Qin J, Chen Y, Han J, Feng X, Han L, Feng S, Liang H, Cen L, Wu X, Huang C, Deng H, Cao Z, Yao H, Lan R, Wang X, Ren S. Partial Restoration of Spinal Cord Neural Continuity via Sural Nerve Transplantation Using a Technique of Spinal Cord Fusion. Front Neurosci 2022; 16:808983. [PMID: 35237120 PMCID: PMC8882688 DOI: 10.3389/fnins.2022.808983] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2021] [Accepted: 01/24/2022] [Indexed: 11/13/2022] Open
Abstract
BackgroundSpinal cord injury (SCI) can cause paralysis and serious chronic morbidity, and there is no effective treatment. Based on our previous experimental results of spinal cord fusion (SCF) in mice, rats, beagles, and monkeys, we developed a surgical protocol of SCF for paraplegic human patients. We designed a novel surgical procedure of SCF, called sural nerve transplantation (SNT), for human patients with lower thoracic SCI and distal cord dysfunction.MethodsWe conducted a clinical trial (ChiCTR2000030788) and performed SNT in 12 fully paraplegic patients due to SCI between T1 and T12. We assessed pre- and postoperative central nerve pain, motor function, sensory function, and autonomic nerve function. Conduction of action potentials across the sural nerve transplant was evaluated. Neural continuity was also examined by diffusion tensor imaging (DTI).ResultsAmong the 12 paraplegic patients enrolled in this clinical trial, seven patients demonstrated improved autonomic nerve functions. Seven patients had clinically significant relief of their symptoms of cord central pain. One patient, however, developed postoperative cord central pain (VAS: 4). Five patients had varying degrees of recovered sensory and/or motor functions below the single neurologic level 1 month after surgery. One patient showed recovery of electrophysiologic, motor-evoked potentials 6 months after the operation. At 6 months after surgery, DTI indicated fusion and nerve connections of white cord and sural nerves in seven patients.ConclusionSNT was able to fuse the axonal stumps of white cord and sural nerve and at least partially improve the cord central pain in most patients. Although SNT did not restore the spinal cord continuity in white matter in some patients, SNT could restore spinal cord continuity in the cortico-trunco-reticulo-propriospinal pathway, thereby restoring in part some motor and sensory functions. SNT may therefore be a safe, feasible, and effective method to treat paraplegic patients with SCI. Future clinical trials should be performed to optimize the type/technique of nerve transplantation, reduce surgical damage, and minimize postoperative scar formation and adhesion, to avoid postoperative cord central pain.Clinical Trial Registration[http://www.chictr.org.cn/showproj.aspx?proj=50526], identifier [ChiCTR2000030788].
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Affiliation(s)
- Xiaoping Ren
- Department of Orthopedics, Ruikang Hospital Affiliated to Guangxi University of Chinese Medicine, Nanning, China
- Institute of Orthopedics, Ruikang Hospital Affiliated to Guangxi University of Chinese Medicine, Nanning, China
- Global Initiative to Cure Paralysis (GICUP), Columbus, OH, United States
- *Correspondence: Xiaoping Ren, ;
| | - Weihua Zhang
- Department of Orthopedics, Ruikang Hospital Affiliated to Guangxi University of Chinese Medicine, Nanning, China
- Institute of Orthopedics, Ruikang Hospital Affiliated to Guangxi University of Chinese Medicine, Nanning, China
- Global Initiative to Cure Paralysis (GICUP), Columbus, OH, United States
| | - Jian Mo
- Department of Orthopedics, Ruikang Hospital Affiliated to Guangxi University of Chinese Medicine, Nanning, China
| | - Jie Qin
- Department of Orthopedics, Ruikang Hospital Affiliated to Guangxi University of Chinese Medicine, Nanning, China
- Institute of Orthopedics, Ruikang Hospital Affiliated to Guangxi University of Chinese Medicine, Nanning, China
| | - Yi Chen
- Department of Orthopedics, Ruikang Hospital Affiliated to Guangxi University of Chinese Medicine, Nanning, China
| | - Jie Han
- Department of Orthopedics, Ruikang Hospital Affiliated to Guangxi University of Chinese Medicine, Nanning, China
| | - Xinjian Feng
- Department of Orthopedics, Ruikang Hospital Affiliated to Guangxi University of Chinese Medicine, Nanning, China
| | - Linxuan Han
- Department of Orthopedics, Ruikang Hospital Affiliated to Guangxi University of Chinese Medicine, Nanning, China
- Institute of Orthopedics, Ruikang Hospital Affiliated to Guangxi University of Chinese Medicine, Nanning, China
| | - Sitan Feng
- Department of Orthopedics, Ruikang Hospital Affiliated to Guangxi University of Chinese Medicine, Nanning, China
| | - Haibo Liang
- Department of Orthopedics, Ruikang Hospital Affiliated to Guangxi University of Chinese Medicine, Nanning, China
| | - Liangjue Cen
- Department of Orthopedics, Ruikang Hospital Affiliated to Guangxi University of Chinese Medicine, Nanning, China
| | - Xiaofei Wu
- Department of Orthopedics, Ruikang Hospital Affiliated to Guangxi University of Chinese Medicine, Nanning, China
- Institute of Orthopedics, Ruikang Hospital Affiliated to Guangxi University of Chinese Medicine, Nanning, China
| | - Chunxing Huang
- Department of Orthopedics, Ruikang Hospital Affiliated to Guangxi University of Chinese Medicine, Nanning, China
| | - Haixuan Deng
- Department of Imaging, Ruikang Hospital Affiliated to Guangxi University of Chinese Medicine, Nanning, China
| | - Zhenbin Cao
- Department of Imaging, Ruikang Hospital Affiliated to Guangxi University of Chinese Medicine, Nanning, China
| | - Huihui Yao
- Department of Electrophysiology, Ruikang Hospital Affiliated to Guangxi University of Chinese Medicine, Nanning, China
| | - Rongyu Lan
- Department of Orthopedics, Ruikang Hospital Affiliated to Guangxi University of Chinese Medicine, Nanning, China
- Institute of Orthopedics, Ruikang Hospital Affiliated to Guangxi University of Chinese Medicine, Nanning, China
| | - Xiaogang Wang
- Department of Orthopedics, Ruikang Hospital Affiliated to Guangxi University of Chinese Medicine, Nanning, China
| | - Shuai Ren
- Global Initiative to Cure Paralysis (GICUP), Columbus, OH, United States
- Department of Orthopedics, The Second Affiliated Hospital of Harbin Medical University, Harbin, China
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Eliseeva NM, Serova NK, Pitskhelauri DI, Kuchina OB, Kudieva ES. [Retrograde degeneration of visual pathway]. ZHURNAL VOPROSY NEIROKHIRURGII IMENI N. N. BURDENKO 2021; 85:92-96. [PMID: 34951765 DOI: 10.17116/neiro20218506192] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
BACKGROUND Optical coherence tomography (OCT) gives the opportunity to examine retrograde degeneration of visual pathway damaged at various levels. OBJECTIVE To estimate OCT data on retrograde degeneration of visual pathway damaged at various levels. MATERIAL AND METHODS Ganglion cell layer (GCL) thickness was measured by OCT in 79 patients with visual pathway damaged at various levels and known duration of visual disturbances. Twenty-One patients were diagnosed with traumatic lesions of the optic nerves and/or chiasma. Fifty-eight patients had retro-genicular visual pathway damage. Thirty-three patients were examined for postoperative homonymous hemianopia after surgery for drug-resistant temporal lobe epilepsy. Twenty-five patients were diagnosed with occipital lobe damage following stroke (12 patients), surgery for arteriovenous malformation (11 patients) and traumatic brain injury (2 patients). All patients underwent assessment of visual acuity, automatic static perimetry, MRI/CT of the brain. Retinal ganglion cell complex was analyzed during OCT. RESULTS GCL thinning following anterior visual pathway damage was detected in 20 out of 21 patients after ≥22 days. In case of post-genicular visual pathway damage, GCL thinning was found in 25 out of 58 patients (9 out of 33 ones after surgery for temporal lobe epilepsy and 16 out of 25 patients with occipital lobe lesion). After surgery for temporal lobe epilepsy, minimum period until GCL thinning detection after previous visual pathway damage was 3 months, in case of occipital lobe lesion - 5 months. CONCLUSION Retrograde visual pathway degeneration is followed by GCL thinning and depends on the level of visual pathway lesion.
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Affiliation(s)
| | - N K Serova
- Burdenko Neurosurgical Center, Moscow, Russia
| | | | - O B Kuchina
- Burdenko Neurosurgical Center, Moscow, Russia
| | - E S Kudieva
- Burdenko Neurosurgical Center, Moscow, Russia
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Unraveling Axon Guidance during Axotomy and Regeneration. Int J Mol Sci 2021; 22:ijms22158344. [PMID: 34361110 PMCID: PMC8347220 DOI: 10.3390/ijms22158344] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2021] [Revised: 07/28/2021] [Accepted: 07/29/2021] [Indexed: 02/06/2023] Open
Abstract
During neuronal development and regeneration axons extend a cytoskeletal-rich structure known as the growth cone, which detects and integrates signals to reach its final destination. The guidance cues “signals” bind their receptors, activating signaling cascades that result in the regulation of the growth cone cytoskeleton, defining growth cone advance, pausing, turning, or collapse. Even though much is known about guidance cues and their isolated mechanisms during nervous system development, there is still a gap in the understanding of the crosstalk between them, and about what happens after nervous system injuries. After neuronal injuries in mammals, only axons in the peripheral nervous system are able to regenerate, while the ones from the central nervous system fail to do so. Therefore, untangling the guidance cues mechanisms, as well as their behavior and characterization after axotomy and regeneration, are of special interest for understanding and treating neuronal injuries. In this review, we present findings on growth cone guidance and canonical guidance cues mechanisms, followed by a description and comparison of growth cone pathfinding mechanisms after axotomy, in regenerative and non-regenerative animal models.
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Ueno M, Nakamura Y, Nakagawa H, Niehaus JK, Maezawa M, Gu Z, Kumanogoh A, Takebayashi H, Lu QR, Takada M, Yoshida Y. Olig2-Induced Semaphorin Expression Drives Corticospinal Axon Retraction After Spinal Cord Injury. Cereb Cortex 2020; 30:5702-5716. [PMID: 32564090 DOI: 10.1093/cercor/bhaa142] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2020] [Revised: 05/02/2020] [Accepted: 05/03/2020] [Indexed: 12/24/2022] Open
Abstract
Axon regeneration is limited in the central nervous system, which hinders the reconstruction of functional circuits following spinal cord injury (SCI). Although various extrinsic molecules to repel axons following SCI have been identified, the role of semaphorins, a major class of axon guidance molecules, has not been thoroughly explored. Here we show that expression of semaphorins, including Sema5a and Sema6d, is elevated after SCI, and genetic deletion of either molecule or their receptors (neuropilin1 and plexinA1, respectively) suppresses axon retraction or dieback in injured corticospinal neurons. We further show that Olig2+ cells are essential for SCI-induced semaphorin expression, and that Olig2 binds to putative enhancer regions of the semaphorin genes. Finally, conditional deletion of Olig2 in the spinal cord reduces the expression of semaphorins, alleviating the axon retraction. These results demonstrate that semaphorins function as axon repellents following SCI, and reveal a novel transcriptional mechanism for controlling semaphorin levels around injured neurons to create zones hostile to axon regrowth.
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Affiliation(s)
- Masaki Ueno
- Department of System Pathology for Neurological Disorders, Brain Research Institute, Niigata University, Niigata 951-8585, Japan.,Division of Developmental Biology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH 45229, USA.,Precursory Research for Embryonic Science and Technology (PRESTO), Japan Science and Technology Agency (JST), Kawaguchi 332-0012, Japan
| | - Yuka Nakamura
- Department of System Pathology for Neurological Disorders, Brain Research Institute, Niigata University, Niigata 951-8585, Japan.,Division of Developmental Biology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH 45229, USA
| | - Hiroshi Nakagawa
- Systems Neuroscience Section, Primate Research Institute, Kyoto University, Inuyama 484-8506, Japan.,Department of Molecular Neuroscience, WPI Immunology Frontier Research Center, Osaka University, Suita 565-0871, Japan
| | - Jesse K Niehaus
- Division of Developmental Biology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH 45229, USA.,Precursory Research for Embryonic Science and Technology (PRESTO), Japan Science and Technology Agency (JST), Kawaguchi 332-0012, Japan
| | - Mari Maezawa
- Division of Developmental Biology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH 45229, USA
| | - Zirong Gu
- Division of Developmental Biology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH 45229, USA.,Zuckerman Mind Brain Behavior Institute, Columbia University, New York, NY 10027, USA
| | - Atsushi Kumanogoh
- Department of Respiratory Medicine, Allergy and Rheumatic Diseases, Graduate School of Medicine, Osaka University, Suita 565-0871, Japan
| | - Hirohide Takebayashi
- Division of Neurobiology and Anatomy, Graduate School of Medical and Dental Sciences, Niigata University, Niigata 951-8510, Japan
| | - Qing Richard Lu
- Division of Experimental Hematology and Cancer Biology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH 45229, USA
| | - Masahiko Takada
- Systems Neuroscience Section, Primate Research Institute, Kyoto University, Inuyama 484-8506, Japan
| | - Yutaka Yoshida
- Division of Developmental Biology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH 45229, USA.,Neural Connectivity Development in Physiology and Disease Laboratory, Burke Neurological Institute, White Plains, NY 10605, USA.,Brain and Mind Research Institute, Weill Cornell Medicine, New York, NY 10065, USA
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11
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Smith DR, Dumont CM, Ciciriello AJ, Guo A, Tatineni R, Munsell MK, Cummings BJ, Anderson AJ, Shea LD. PLG Bridge Implantation in Chronic SCI Promotes Axonal Elongation and Myelination. ACS Biomater Sci Eng 2019; 5:6679-6690. [PMID: 33423486 DOI: 10.1021/acsbiomaterials.9b01012] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Spinal cord injury (SCI) is a devastating condition that may cause permanent functional loss below the level of injury, including paralysis and loss of bladder, bowel, and sexual function. Patients are rarely treated immediately, and this delay is associated with tissue loss and scar formation that can make regeneration at chronic time points more challenging. Herein, we investigated regeneration using a poly(lactide-co-glycolide) multichannel bridge implanted into a chronic SCI following surgical resection of necrotic tissue. We characterized the dynamic injury response and noted that scar formation decreased at 4 and 8 weeks postinjury (wpi), yet macrophage infiltration increased between 4 and 8 wpi. Subsequently, the scar tissue was resected and bridges were implanted at 4 and 8 wpi. We observed robust axon growth into the bridge and remyelination at 6 months after initial injury. Axon densities were increased for 8 week bridge implantation relative to 4 week bridge implantation, whereas greater myelination, particularly by Schwann cells, was observed with 4 week bridge implantation. The process of bridge implantation did not significantly decrease the postinjury function. Collectively, this chronic model follows the pathophysiology of human SCI, and bridge implantation allows for clear demarcation of the regenerated tissue. These data demonstrate that bridge implantation into chronic SCI supports regeneration and provides a platform to investigate strategies to buttress and expand regeneration of neural tissue at chronic time points.
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Affiliation(s)
- Dominique R Smith
- Department of Biomedical Engineering, University of Michigan, 2200 Bonisteel Avenue, Ann Arbor, Michigan 48109, United States
| | - Courtney M Dumont
- Department of Biomedical Engineering, University of Miami, 1251 Memorial Drive, Coral Gables, Florida 33156, United States.,Biomedical Nanotechnology Institute at University of Miami (BioNIUM), University of Miami, 1951 NW 7th Avenue Ste 475, Miami, Florida 33136, United States
| | - Andrew J Ciciriello
- Department of Biomedical Engineering, University of Michigan, 2200 Bonisteel Avenue, Ann Arbor, Michigan 48109, United States.,Department of Biomedical Engineering, University of Miami, 1251 Memorial Drive, Coral Gables, Florida 33156, United States.,Biomedical Nanotechnology Institute at University of Miami (BioNIUM), University of Miami, 1951 NW 7th Avenue Ste 475, Miami, Florida 33136, United States
| | - Amina Guo
- Department of Biomedical Engineering, University of Michigan, 2200 Bonisteel Avenue, Ann Arbor, Michigan 48109, United States
| | - Ravindra Tatineni
- Department of Biomedical Engineering, University of Michigan, 2200 Bonisteel Avenue, Ann Arbor, Michigan 48109, United States
| | - Mary K Munsell
- Department of Biomedical Engineering, University of Michigan, 2200 Bonisteel Avenue, Ann Arbor, Michigan 48109, United States
| | - Brian J Cummings
- Institute for Memory Impairments and Neurological Disorders (iMIND), University of California, Irvine, 1100 Gottschalk Medical Plaza, Irvine, California 92697, United States.,Sue and Bill Gross Stem Cell Research Center, University of California, Irvine, 845 Health Science Road, Irvine, California 92697, United States.,Department of Anatomy and Neurobiology, University of California, Irvine, 364 Med Surge II, Irvine, California 92697, United States.,Department of Physical Medicine and Rehabilitation, University of California, Irvine, 101 The City Drive South, Building 53, Suite 311A, Orange, California 92868, United States
| | - Aileen J Anderson
- Institute for Memory Impairments and Neurological Disorders (iMIND), University of California, Irvine, 1100 Gottschalk Medical Plaza, Irvine, California 92697, United States.,Sue and Bill Gross Stem Cell Research Center, University of California, Irvine, 845 Health Science Road, Irvine, California 92697, United States.,Department of Anatomy and Neurobiology, University of California, Irvine, 364 Med Surge II, Irvine, California 92697, United States.,Department of Physical Medicine and Rehabilitation, University of California, Irvine, 101 The City Drive South, Building 53, Suite 311A, Orange, California 92868, United States
| | - Lonnie D Shea
- Department of Biomedical Engineering, University of Michigan, 2200 Bonisteel Avenue, Ann Arbor, Michigan 48109, United States.,Department of Chemical Engineering, University of Michigan, 2300 Hayward Street, Ann Arbor, Michigan 48109, United States
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12
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Duncan GJ, Manesh SB, Hilton BJ, Assinck P, Plemel JR, Tetzlaff W. The fate and function of oligodendrocyte progenitor cells after traumatic spinal cord injury. Glia 2019; 68:227-245. [PMID: 31433109 DOI: 10.1002/glia.23706] [Citation(s) in RCA: 57] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2019] [Revised: 07/24/2019] [Accepted: 08/01/2019] [Indexed: 12/27/2022]
Abstract
Oligodendrocyte progenitor cells (OPCs) are the most proliferative and dispersed population of progenitor cells in the adult central nervous system, which allows these cells to rapidly respond to damage. Oligodendrocytes and myelin are lost after traumatic spinal cord injury (SCI), compromising efficient conduction and, potentially, the long-term health of axons. In response, OPCs proliferate and then differentiate into new oligodendrocytes and Schwann cells to remyelinate axons. This culminates in highly efficient remyelination following experimental SCI in which nearly all intact demyelinated axons are remyelinated in rodent models. However, myelin regeneration comprises only one role of OPCs following SCI. OPCs contribute to scar formation after SCI and restrict the regeneration of injured axons. Moreover, OPCs alter their gene expression following demyelination, express cytokines and perpetuate the immune response. Here, we review the functional contribution of myelin regeneration and other recently uncovered roles of OPCs and their progeny to repair following SCI.
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Affiliation(s)
- Greg J Duncan
- Department of Neurology, Jungers Center for Neurosciences Research, Oregon Health and Science University, Portland, Oregon
| | - Sohrab B Manesh
- Graduate Program in Neuroscience, International Collaboration on Repair Discoveries (ICORD), University of British Columbia (UBC), Vancouver, British Columbia, Canada
| | - Brett J Hilton
- Deutsches Zentrum für Neurodegenerative Erkrankungen (DZNE), Bonn, Germany
| | - Peggy Assinck
- MRC Centre for Regenerative Medicine, University of Edinburgh, Edinburgh, UK
| | - Jason R Plemel
- Department of Medicine, Division of Neurology, Neuroscience and Mental Health Institute, University of Alberta, Calgary, Alberta, Canada
| | - Wolfram Tetzlaff
- Graduate Program in Neuroscience, International Collaboration on Repair Discoveries (ICORD), University of British Columbia (UBC), Vancouver, British Columbia, Canada.,Departments of Zoology and Surgery, University of British Columbia, Vancouver, British Columbia, Canada
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13
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Katoh H, Yokota K, Fehlings MG. Regeneration of Spinal Cord Connectivity Through Stem Cell Transplantation and Biomaterial Scaffolds. Front Cell Neurosci 2019; 13:248. [PMID: 31244609 PMCID: PMC6563678 DOI: 10.3389/fncel.2019.00248] [Citation(s) in RCA: 104] [Impact Index Per Article: 20.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2019] [Accepted: 05/17/2019] [Indexed: 12/20/2022] Open
Abstract
Significant progress has been made in the treatment of spinal cord injury (SCI). Advances in post-trauma management and intensive rehabilitation have significantly improved the prognosis of SCI and converted what was once an “ailment not to be treated” into a survivable injury, but the cold hard fact is that we still do not have a validated method to improve the paralysis of SCI. The irreversible functional impairment of the injured spinal cord is caused by the disruption of neuronal transduction across the injury lesion, which is brought about by demyelination, axonal degeneration, and loss of synapses. Furthermore, refractory substrates generated in the injured spinal cord inhibit spontaneous recovery. The discovery of the regenerative capability of central nervous system neurons in the proper environment and the verification of neural stem cells in the spinal cord once incited hope that a cure for SCI was on the horizon. That hope was gradually replaced with mounting frustration when neuroprotective drugs, cell transplantation, and strategies to enhance remyelination, axonal regeneration, and neuronal plasticity demonstrated significant improvement in animal models of SCI but did not translate into a cure in human patients. However, recent advances in SCI research have greatly increased our understanding of the fundamental processes underlying SCI and fostered increasing optimism that these multiple treatment strategies are finally coming together to bring about a new era in which we will be able to propose encouraging therapies that will lead to appreciable improvements in SCI patients. In this review, we outline the pathophysiology of SCI that makes the spinal cord refractory to regeneration and discuss the research that has been done with cell replacement and biomaterial implantation strategies, both by itself and as a combined treatment. We will focus on the capacity of these strategies to facilitate the regeneration of neural connectivity necessary to achieve meaningful functional recovery after SCI.
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Affiliation(s)
- Hiroyuki Katoh
- Division of Genetics and Development, Krembil Research Institute, Toronto, ON, Canada.,Department of Orthopaedic Surgery - Surgical Sciences, School of Medicine, Tokai University, Tokyo, Japan
| | - Kazuya Yokota
- Division of Genetics and Development, Krembil Research Institute, Toronto, ON, Canada.,Department of Orthopaedic Surgery, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan
| | - Michael G Fehlings
- Division of Genetics and Development, Krembil Research Institute, Toronto, ON, Canada.,Institute of Medical Science, University of Toronto, Toronto, ON, Canada.,Division of Neurosurgery, University of Toronto, Toronto, ON, Canada.,Spine Program, Toronto Western Hospital, University Health Network, Toronto, ON, Canada
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14
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Xi F, Xu RJ, Xu JH, Ma JJ, Wang WH, Wang F, Ma YX, Qi SB, Zhang HC, Zhang HN, Qin XZ, Chen JQ, Li B, Liu CM, Yang HL, Meng B, Saijilafu. Calcium/calmodulin-dependent protein kinase II regulates mammalian axon growth by affecting F-actin length in growth cone. J Cell Physiol 2019; 234:23053-23065. [PMID: 31134625 DOI: 10.1002/jcp.28867] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2019] [Revised: 05/09/2019] [Accepted: 05/09/2019] [Indexed: 12/21/2022]
Abstract
While axon regeneration is a key determinant of functional recovery of the nervous system after injury, it is often poor in the mature nervous system. Influx of extracellular calcium (Ca2+ ) is one of the first phenomena that occur following axonal injury, and calcium/calmodulin-dependent protein kinase II (CaMKII), a target substrate for calcium ions, regulates the status of cytoskeletal proteins such as F-actin. Herein, we found that peripheral axotomy activates CaMKII in dorsal root ganglion (DRG) sensory neurons, and inhibition of CaMKII impairs axon outgrowth in both the peripheral and central nervous systems (PNS and CNS, respectively). Most importantly, we also found that the activation of CaMKII promotes PNS and CNS axon growth, and regulatory effects of CaMKII on axon growth occur via affecting the length of the F-actin. Thus, we believe our findings provide clear evidence that CaMKII is a critical modulator of mammalian axon regeneration.
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Affiliation(s)
- Feng Xi
- Department of Orthopaedics, The First Affiliated Hospital of Soochow University, Orthopedic Institute, Soochow University, Suzhou, Jiangsu, P. R. China
| | - Ren-Jie Xu
- Department of Orthopaedics, The First Affiliated Hospital of Soochow University, Orthopedic Institute, Soochow University, Suzhou, Jiangsu, P. R. China.,Department of Orthopaedics, Suzhou Municipal Hospital, The Affiliated Hospital of Nanjing Medical University, Suzhou, Jiangsu, P. R. China
| | - Jin-Hui Xu
- Department of Orthopaedics, The First Affiliated Hospital of Soochow University, Orthopedic Institute, Soochow University, Suzhou, Jiangsu, P. R. China
| | - Jin-Jin Ma
- Department of Orthopaedics, The First Affiliated Hospital of Soochow University, Orthopedic Institute, Soochow University, Suzhou, Jiangsu, P. R. China
| | - Wei-Hua Wang
- Department of Orthopaedics, The First Affiliated Hospital of Soochow University, Orthopedic Institute, Soochow University, Suzhou, Jiangsu, P. R. China
| | - Feng Wang
- Department of Orthopaedics, The First Affiliated Hospital of Soochow University, Orthopedic Institute, Soochow University, Suzhou, Jiangsu, P. R. China
| | - Yan-Xia Ma
- Department of Orthopaedics, The First Affiliated Hospital of Soochow University, Orthopedic Institute, Soochow University, Suzhou, Jiangsu, P. R. China
| | - Shi-Bin Qi
- Department of Orthopaedics, The First Affiliated Hospital of Soochow University, Orthopedic Institute, Soochow University, Suzhou, Jiangsu, P. R. China
| | - Hong-Cheng Zhang
- Department of Orthopaedics, The First Affiliated Hospital of Soochow University, Orthopedic Institute, Soochow University, Suzhou, Jiangsu, P. R. China
| | - Hao-Nan Zhang
- Department of Orthopaedics, The First Affiliated Hospital of Soochow University, Orthopedic Institute, Soochow University, Suzhou, Jiangsu, P. R. China
| | - Xu-Zhen Qin
- Department of Orthopaedics, The First Affiliated Hospital of Soochow University, Orthopedic Institute, Soochow University, Suzhou, Jiangsu, P. R. China
| | - Jian-Quan Chen
- Department of Orthopaedics, The First Affiliated Hospital of Soochow University, Orthopedic Institute, Soochow University, Suzhou, Jiangsu, P. R. China
| | - Bin Li
- Department of Orthopaedics, The First Affiliated Hospital of Soochow University, Orthopedic Institute, Soochow University, Suzhou, Jiangsu, P. R. China
| | - Chang-Mei Liu
- State Key Laboratory of Stem Cell and Reproductive Biology, Institute of Zoology, Chinese Academy of Science, Beijing, P. R. China.,Savaid Medical School, University of Chinese Academy of Sciences, Beijing, China
| | - Hui-Lin Yang
- Department of Orthopaedics, The First Affiliated Hospital of Soochow University, Orthopedic Institute, Soochow University, Suzhou, Jiangsu, P. R. China
| | - Bin Meng
- Department of Orthopaedics, The First Affiliated Hospital of Soochow University, Orthopedic Institute, Soochow University, Suzhou, Jiangsu, P. R. China
| | - Saijilafu
- Department of Orthopaedics, The First Affiliated Hospital of Soochow University, Orthopedic Institute, Soochow University, Suzhou, Jiangsu, P. R. China
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15
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Hassannejad Z, Yousefifard M, Azizi Y, Zadegan SA, Sajadi K, Sharif-Alhoseini M, Shakouri-Motlagh A, Mokhatab M, Rezvan M, Shokraneh F, Hosseini M, Vaccaro AR, Harrop JS, Rahimi-Movaghar V. Axonal degeneration and demyelination following traumatic spinal cord injury: A systematic review and meta-analysis. J Chem Neuroanat 2019; 97:9-22. [PMID: 30726717 DOI: 10.1016/j.jchemneu.2019.01.009] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2018] [Revised: 12/22/2018] [Accepted: 01/22/2019] [Indexed: 12/17/2022]
Abstract
The pathophysiology of spinal cord injury (SCI) related processes of axonal degeneration and demyelination are poorly understood. The present systematic review and meta-analysis were performed such to establish quantitative results of animal studies regarding the role of injury severity, SCI models and level of injury on the pathophysiology of axon and myelin sheath degeneration. 39 related articles were included in the analysis. The compiled data showed that the total number of axons, number of myelinated axons, myelin sheath thickness, axonal conduction velocity, and internode length steadily decreased as time elapsed from the injury (Pfor trend<0.0001). The rate of axonal retrograde degeneration was affected by SCI model and severity of the injury. Axonal degeneration was higher in injuries of the thoracic region. The SCI model and the site of the injury also affected axonal retrograde degeneration. The number of myelinated axons in the caudal region of the injury was significantly higher than the lesion site and the rostral region. The findings of the present meta-analysis show that the pathophysiology of axons and myelin sheath differ in various phases of SCI and are affected by multiple factors related to the injury.
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Affiliation(s)
- Zahra Hassannejad
- Pediatric Urology and Regenerative Medicine Research Center, Children's Hospital Medical Center, Tehran University of Medical Sciences, Tehran, Iran; Sina Trauma and Surgery Research Center, Tehran University of Medical Sciences, Tehran, Iran
| | - Mahmoud Yousefifard
- Physiology Research Center, Faculty of Medicine, Iran University of Medical Sciences, Tehran, Iran
| | - Yaser Azizi
- Physiology Research Center, Faculty of Medicine, Iran University of Medical Sciences, Tehran, Iran
| | - Shayan Abdollah Zadegan
- Sina Trauma and Surgery Research Center, Tehran University of Medical Sciences, Tehran, Iran
| | - Kiavash Sajadi
- Sina Trauma and Surgery Research Center, Tehran University of Medical Sciences, Tehran, Iran
| | - Mahdi Sharif-Alhoseini
- Sina Trauma and Surgery Research Center, Tehran University of Medical Sciences, Tehran, Iran
| | - Aida Shakouri-Motlagh
- Department of Chemical and Biomolecular Engineering, University of Melbourne, Victoria 3010, Australia
| | - Mona Mokhatab
- Sina Trauma and Surgery Research Center, Tehran University of Medical Sciences, Tehran, Iran
| | - Motahareh Rezvan
- Sina Trauma and Surgery Research Center, Tehran University of Medical Sciences, Tehran, Iran
| | - Farhad Shokraneh
- Cochrane Schizophrenia Group, Institute of Mental Health, University of Nottingham, Nottingham, UK
| | - Mostafa Hosseini
- Department of Epidemiology and Biostatistics, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran
| | - Alexander R Vaccaro
- Department of Orthopedics and Neurosurgery, Rothman Institute, Thomas Jefferson University Philadelphia, USA
| | - James S Harrop
- Department of Neurosurgery, Thomas Jefferson University, Philadelphia, Pennsylvania, USA
| | - Vafa Rahimi-Movaghar
- Sina Trauma and Surgery Research Center, Tehran University of Medical Sciences, Tehran, Iran; Department of Neurosurgery, Thomas Jefferson University, Philadelphia, Pennsylvania, USA; Brain and Spinal Injuries Research Center (BASIR), Neuroscience Institute, Imam Khomeini Hospital, Tehran University of Medical Sciences, Tehran, Iran.
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16
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Yokota K, Kubota K, Kobayakawa K, Saito T, Hara M, Kijima K, Maeda T, Katoh H, Ohkawa Y, Nakashima Y, Okada S. Pathological changes of distal motor neurons after complete spinal cord injury. Mol Brain 2019; 12:4. [PMID: 30626449 PMCID: PMC6327522 DOI: 10.1186/s13041-018-0422-3] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2018] [Accepted: 12/11/2018] [Indexed: 12/15/2022] Open
Abstract
Traumatic spinal cord injury (SCI) causes serious disruption of neuronal circuits that leads to motor functional deficits. Regeneration of disrupted circuits back to their original target is necessary for the restoration of function after SCI, but the pathophysiological condition of the caudal spinal cord has not been sufficiently studied. Here we investigated the histological and biological changes in the distal part of the injured spinal cord, using a mice model of complete thoracic SCI in the chronic stage (3 months after injury). Atrophic changes were widely observed in the injured spinal cord both rostral and caudal to the lesion, but the decrease in area was mainly in the white matter in the rostral spinal cord while both the white and gray matter decreased in the caudal spinal cord. The number of the motor neurons was maintained in the chronic phase of injury, but the number of presynaptic boutons decreased in the lumbar motor neurons caudal to the lesion. Using laser microdissection, to investigate gene expressions in motor neurons caudal to the lesion, we observed a decrease in the expressions of neuronal activity markers. However, we found that the synaptogenic potential of postsynapse molecules was maintained in the motor neurons after SCI with the expression of acetylcholine-related molecules actually higher after SCI. Collectively, our results show that the potential of synaptogenesis is maintained in the motor neurons caudal to the lesion, even though presynaptic input is decreased. Although researches into SCI concentrate their effort on the lesion epicenter, our findings suggest that the area caudal to the lesion could be an original therapeutic target for the chronically injured spinal cord.
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Affiliation(s)
- Kazuya Yokota
- Department of Orthopaedic Surgery, Graduate School of Medical Sciences, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka, 812-8582, Japan.,Department of Immunology and Neuroscience, Medical Institute of Bioregulation, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka, 812-8582, Japan.,Department of Orthopaedic Surgery, Spinal Injuries Center, 550-4 Igisu, Iizuka, Fukuoka, 820-8508, Japan
| | - Kensuke Kubota
- Department of Orthopaedic Surgery, Graduate School of Medical Sciences, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka, 812-8582, Japan.,Department of Immunology and Neuroscience, Medical Institute of Bioregulation, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka, 812-8582, Japan.,Department of Orthopaedic Surgery, Spinal Injuries Center, 550-4 Igisu, Iizuka, Fukuoka, 820-8508, Japan
| | - Kazu Kobayakawa
- Department of Orthopaedic Surgery, Graduate School of Medical Sciences, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka, 812-8582, Japan.,Department of Immunology and Neuroscience, Medical Institute of Bioregulation, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka, 812-8582, Japan
| | - Takeyuki Saito
- Department of Orthopaedic Surgery, Graduate School of Medical Sciences, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka, 812-8582, Japan.,Department of Immunology and Neuroscience, Medical Institute of Bioregulation, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka, 812-8582, Japan
| | - Masamitsu Hara
- Department of Orthopaedic Surgery, Graduate School of Medical Sciences, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka, 812-8582, Japan.,Department of Immunology and Neuroscience, Medical Institute of Bioregulation, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka, 812-8582, Japan
| | - Ken Kijima
- Department of Orthopaedic Surgery, Graduate School of Medical Sciences, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka, 812-8582, Japan.,Department of Immunology and Neuroscience, Medical Institute of Bioregulation, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka, 812-8582, Japan
| | - Takeshi Maeda
- Department of Orthopaedic Surgery, Spinal Injuries Center, 550-4 Igisu, Iizuka, Fukuoka, 820-8508, Japan
| | - Hiroyuki Katoh
- Department of Orthopaedic Surgery, Tokai University School of Medicine, 143 Shimokasuya, Isehara, Kanagawa, 259-1193, Japan
| | - Yasuyuki Ohkawa
- Department of Transcriptomics, JST-CREST, Medical Institute of Bioregulation, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka, 812-8582, Japan
| | - Yasuharu Nakashima
- Department of Orthopaedic Surgery, Graduate School of Medical Sciences, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka, 812-8582, Japan
| | - Seiji Okada
- Department of Orthopaedic Surgery, Graduate School of Medical Sciences, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka, 812-8582, Japan. .,Department of Immunology and Neuroscience, Medical Institute of Bioregulation, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka, 812-8582, Japan.
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17
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Caprelli MT, Mothe AJ, Tator CH. Hyperphosphorylated Tau as a Novel Biomarker for Traumatic Axonal Injury in the Spinal Cord. J Neurotrauma 2018; 35:1929-1941. [DOI: 10.1089/neu.2017.5495] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Affiliation(s)
- Mitchell T. Caprelli
- University of Toronto, Institute of Medical Science, Toronto, Ontario, Canada
- Division of Genetics and Development, Krembil Research Institute, Toronto, Ontario, Canada
| | - Andrea J. Mothe
- Division of Genetics and Development, Krembil Research Institute, Toronto, Ontario, Canada
| | - Charles H. Tator
- University of Toronto, Institute of Medical Science, Toronto, Ontario, Canada
- Division of Genetics and Development, Krembil Research Institute, Toronto, Ontario, Canada
- Division of Neurosurgery, Toronto Western Hospital, Toronto, Ontario, Canada
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18
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Orem BC, Pelisch N, Williams J, Nally JM, Stirling DP. Intracellular calcium release through IP 3 R or RyR contributes to secondary axonal degeneration. Neurobiol Dis 2017; 106:235-243. [DOI: 10.1016/j.nbd.2017.07.011] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2017] [Revised: 06/28/2017] [Accepted: 07/10/2017] [Indexed: 11/27/2022] Open
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19
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The toll-like receptor 2 agonist Pam3CSK4 is neuroprotective after spinal cord injury. Exp Neurol 2017; 294:1-11. [DOI: 10.1016/j.expneurol.2017.04.012] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2017] [Revised: 04/20/2017] [Accepted: 04/22/2017] [Indexed: 12/21/2022]
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20
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Hill CE. A view from the ending: Axonal dieback and regeneration following SCI. Neurosci Lett 2017; 652:11-24. [DOI: 10.1016/j.neulet.2016.11.002] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2016] [Revised: 10/20/2016] [Accepted: 11/01/2016] [Indexed: 12/22/2022]
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21
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Canavero S, Ren X, Kim CY, Rosati E. Neurologic foundations of spinal cord fusion (GEMINI). Surgery 2016; 160:11-19. [PMID: 27180142 DOI: 10.1016/j.surg.2016.01.027] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2015] [Revised: 01/08/2016] [Accepted: 01/21/2016] [Indexed: 12/17/2022]
Abstract
Cephalosomatic anastomosis has been carried out in both monkeys and mice with preservation of brain function. Nonetheless the spinal cord was not reconstructed, leaving the animals unable to move voluntarily. Here we review the details of the GEMINI spinal cord fusion protocol, which aims at restoring electrophysiologic conduction across an acutely transected spinal cord. The existence of the cortico-truncoreticulo-propriospinal pathway, a little-known anatomic entity, is described, and its importance concerning spinal cord fusion emphasized. The use of fusogens and electrical stimulation as adjuvants for nerve fusion is addressed. The possibility of achieving cephalosomatic anastomosis in humans has become reality in principle.
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Affiliation(s)
| | - XiaoPing Ren
- Hand and Microsurgical Center, the Second Affiliated Hospital of Harbin Medical University; State-Province Key Laboratories of Biomedicine-Pharmaceutics, Harbin Medical University, Harbin, China; Department of Molecular Pharmacology and Therapeutics, Stritch School of Medicine, Loyola University Chicago, Chicago, IL
| | - C-Yoon Kim
- Department of Bioengineering, College of Life Science, CHA University, Seoul, Korea; Department of Laboratory Animal Medicine, College of Veterinary Medicine, Seoul National University, Seoul, Korea
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22
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Cheng CH, Lin CT, Lee MJ, Tsai MJ, Huang WH, Huang MC, Lin YL, Chen CJ, Huang WC, Cheng H. Local Delivery of High-Dose Chondroitinase ABC in the Sub-Acute Stage Promotes Axonal Outgrowth and Functional Recovery after Complete Spinal Cord Transection. PLoS One 2015; 10:e0138705. [PMID: 26393921 PMCID: PMC4579094 DOI: 10.1371/journal.pone.0138705] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2015] [Accepted: 09/02/2015] [Indexed: 01/11/2023] Open
Abstract
Chondroitin sulfate proteoglycans (CSPGs) are glial scar-associated molecules considered axonal regeneration inhibitors and can be digested by chondroitinase ABC (ChABC) to promote axonal regeneration after spinal cord injury (SCI). We previously demonstrated that intrathecal delivery of low-dose ChABC (1 U) in the acute stage of SCI promoted axonal regrowth and functional recovery. In this study, high-dose ChABC (50 U) introduced via intrathecal delivery induced subarachnoid hemorrhage and death within 48 h. However, most SCI patients are treated in the sub-acute or chronic stages, when the dense glial scar has formed and is minimally digested by intrathecal delivery of ChABC at the injury site. The present study investigated whether intraparenchymal delivery of ChABC in the sub-acute stage of complete spinal cord transection would promote axonal outgrowth and improve functional recovery. We observed no functional recovery following the low-dose ChABC (1 U or 5 U) treatments. Furthermore, animals treated with high-dose ChABC (50 U or 100 U) showed decreased CSPGs levels. The extent and area of the lesion were also dramatically decreased after ChABC treatment. The outgrowth of the regenerating axons was significantly increased, and some partially crossed the lesion site in the ChABC-treated groups. In addition, retrograde Fluoro-Gold (FG) labeling showed that the outgrowing axons could cross the lesion site and reach several brain stem nuclei involved in sensory and motor functions. The Basso, Beattie and Bresnahan (BBB) open field locomotor scores revealed that the ChABC treatment significantly improved functional recovery compared to the control group at eight weeks after treatment. Our study demonstrates that high-dose ChABC treatment in the sub-acute stage of SCI effectively improves glial scar digestion by reducing the lesion size and increasing axonal regrowth to the related functional nuclei, which promotes locomotor recovery. Thus, our results will aid in the treatment of spinal cord injury.
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Affiliation(s)
- Chu-Hsun Cheng
- Program in Molecular Medicine, National Yang-Ming University and Academia Sinica, Taipei, Taiwan
- Institute of Pharmacology, School of Medicine, National Yang-Ming University, Taipei, Taiwan
- Neural Regeneration Laboratory, Department of Neurosurgery, Neurological Institute, Taipei Veterans General Hospital, Taipei, Taiwan
| | - Chi-Te Lin
- Neural Regeneration Laboratory, Department of Neurosurgery, Neurological Institute, Taipei Veterans General Hospital, Taipei, Taiwan
- Department of Nursing, Central Taiwan University of Science and Technology, Taichung, Taiwan
| | - Meng-Jen Lee
- Neural Regeneration Laboratory, Department of Neurosurgery, Neurological Institute, Taipei Veterans General Hospital, Taipei, Taiwan
- Department of Applied Chemistry, Chaoyang University of Technology, Taichung, Taiwan
| | - May-Jywan Tsai
- Neural Regeneration Laboratory, Department of Neurosurgery, Neurological Institute, Taipei Veterans General Hospital, Taipei, Taiwan
| | - Wen-Hung Huang
- Neural Regeneration Laboratory, Department of Neurosurgery, Neurological Institute, Taipei Veterans General Hospital, Taipei, Taiwan
| | - Ming-Chao Huang
- Neural Regeneration Laboratory, Department of Neurosurgery, Neurological Institute, Taipei Veterans General Hospital, Taipei, Taiwan
- Division of Pediatric Neurosurgery, Neurological Institute, Taipei Veterans General Hospital, Taipei, Taiwan
- School of Medicine, Taipei Medical University, Taipei, Taiwan
| | - Yi-Lo Lin
- Neural Regeneration Laboratory, Department of Neurosurgery, Neurological Institute, Taipei Veterans General Hospital, Taipei, Taiwan
- Graduate Institute of Veterinary Pathobiology, College of Veterinary Medicine, National Chung Hsing University, Taichung, Taiwan
| | - Ching-Jung Chen
- Neural Regeneration Laboratory, Department of Neurosurgery, Neurological Institute, Taipei Veterans General Hospital, Taipei, Taiwan
| | - Wen-Cheng Huang
- Neural Regeneration Laboratory, Department of Neurosurgery, Neurological Institute, Taipei Veterans General Hospital, Taipei, Taiwan
- Center for Neural Regeneration, Neurological Institute, Taipei Veterans General Hospital, Taipei, Taiwan
- Department of Neurosurgery, Neurological Institute, Taipei Veterans General Hospital, Taipei, Taiwan
- Department of Medicine, National Yang-Ming University, Taipei, Taiwan
- * E-mail:
| | - Henrich Cheng
- Program in Molecular Medicine, National Yang-Ming University and Academia Sinica, Taipei, Taiwan
- Institute of Pharmacology, School of Medicine, National Yang-Ming University, Taipei, Taiwan
- Neural Regeneration Laboratory, Department of Neurosurgery, Neurological Institute, Taipei Veterans General Hospital, Taipei, Taiwan
- Center for Neural Regeneration, Neurological Institute, Taipei Veterans General Hospital, Taipei, Taiwan
- Department of Neurosurgery, Neurological Institute, Taipei Veterans General Hospital, Taipei, Taiwan
- Department of Medicine, National Yang-Ming University, Taipei, Taiwan
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Okada SLM, Stivers NS, Stys PK, Stirling DP. An ex vivo laser-induced spinal cord injury model to assess mechanisms of axonal degeneration in real-time. J Vis Exp 2014:e52173. [PMID: 25490396 DOI: 10.3791/52173] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
Injured CNS axons fail to regenerate and often retract away from the injury site. Axons spared from the initial injury may later undergo secondary axonal degeneration. Lack of growth cone formation, regeneration, and loss of additional myelinated axonal projections within the spinal cord greatly limits neurological recovery following injury. To assess how central myelinated axons of the spinal cord respond to injury, we developed an ex vivo living spinal cord model utilizing transgenic mice that express yellow fluorescent protein in axons and a focal and highly reproducible laser-induced spinal cord injury to document the fate of axons and myelin (lipophilic fluorescent dye Nile Red) over time using two-photon excitation time-lapse microscopy. Dynamic processes such as acute axonal injury, axonal retraction, and myelin degeneration are best studied in real-time. However, the non-focal nature of contusion-based injuries and movement artifacts encountered during in vivo spinal cord imaging make differentiating primary and secondary axonal injury responses using high resolution microscopy challenging. The ex vivo spinal cord model described here mimics several aspects of clinically relevant contusion/compression-induced axonal pathologies including axonal swelling, spheroid formation, axonal transection, and peri-axonal swelling providing a useful model to study these dynamic processes in real-time. Major advantages of this model are excellent spatiotemporal resolution that allows differentiation between the primary insult that directly injures axons and secondary injury mechanisms; controlled infusion of reagents directly to the perfusate bathing the cord; precise alterations of the environmental milieu (e.g., calcium, sodium ions, known contributors to axonal injury, but near impossible to manipulate in vivo); and murine models also offer an advantage as they provide an opportunity to visualize and manipulate genetically identified cell populations and subcellular structures. Here, we describe how to isolate and image the living spinal cord from mice to capture dynamics of acute axonal injury.
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Affiliation(s)
- Starlyn L M Okada
- KY Spinal Cord Injury Research Center, Department of Neurological Surgery, University of Louisville
| | - Nicole S Stivers
- KY Spinal Cord Injury Research Center, Department of Neurological Surgery, University of Louisville
| | - Peter K Stys
- Hotchkiss Brain Institute, Department of Clinical Neurosciences, University of Calgary
| | - David P Stirling
- KY Spinal Cord Injury Research Center, Department of Neurological Surgery, University of Louisville;
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Examination of the combined effects of chondroitinase ABC, growth factors and locomotor training following compressive spinal cord injury on neuroanatomical plasticity and kinematics. PLoS One 2014; 9:e111072. [PMID: 25350665 PMCID: PMC4211738 DOI: 10.1371/journal.pone.0111072] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2014] [Accepted: 09/23/2014] [Indexed: 12/13/2022] Open
Abstract
While several cellular and pharmacological treatments have been evaluated following spinal cord injury (SCI) in animal models, it is increasingly recognized that approaches to address the glial scar, including the use of chondroitinase ABC (ChABC), can facilitate neuroanatomical plasticity. Moreover, increasing evidence suggests that combinatorial strategies are key to unlocking the plasticity that is enabled by ChABC. Given this, we evaluated the anatomical and functional consequences of ChABC in a combinatorial approach that also included growth factor (EGF, FGF2 and PDGF-AA) treatments and daily treadmill training on the recovery of hindlimb locomotion in rats with mid thoracic clip compression SCI. Using quantitative neuroanatomical and kinematic assessments, we demonstrate that the combined therapy significantly enhanced the neuroanatomical plasticity of major descending spinal tracts such as corticospinal and serotonergic-spinal pathways. Additionally, the pharmacological treatment attenuated chronic astrogliosis and inflammation at and adjacent to the lesion with the modest synergistic effects of treadmill training. We also observed a trend for earlier recovery of locomotion accompanied by an improvement of the overall angular excursions in rats treated with ChABC and growth factors in the first 4 weeks after SCI. At the end of the 7-week recovery period, rats from all groups exhibited an impressive spontaneous recovery of the kinematic parameters during locomotion on treadmill. However, although the combinatorial treatment led to clear chronic neuroanatomical plasticity, these structural changes did not translate to an additional long-term improvement of locomotor parameters studied including hindlimb-forelimb coupling. These findings demonstrate the beneficial effects of combined ChABC, growth factors and locomotor training on the plasticity of the injured spinal cord and the potential to induce earlier neurobehavioral recovery. However, additional approaches such as stem cell therapies or a more adapted treadmill training protocol may be required to optimize this repair strategy in order to induce sustained functional locomotor improvement.
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25
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Guo Y, Foulds RA, Adamovich SV, Sahin M. Encoding of forelimb forces by corticospinal tract activity in the rat. Front Neurosci 2014; 8:62. [PMID: 24847198 PMCID: PMC4013477 DOI: 10.3389/fnins.2014.00062] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2013] [Accepted: 03/17/2014] [Indexed: 01/01/2023] Open
Abstract
In search of a solution to the long standing problems encountered in traditional brain computer interfaces (BCI), the lateral descending tracts of the spinal cord present an alternative site for taping into the volitional motor signals. Due to the convergence of the cortical outputs into a final common pathway in the descending tracts of the spinal cord, neural interfaces with the spinal cord can potentially acquire signals richer with volitional information in a smaller anatomical region. The main objective of this study was to evaluate the feasibility of extracting motor control signals from the corticospinal tract (CST) of the rat spinal cord. Flexible substrate, multi-electrode arrays (MEA) were implanted in the CST of rats trained for a lever pressing task. This novel use of flexible substrate MEAs allowed recording of CST activity in behaving animals for up to three weeks with the current implantation technique. Time-frequency and principal component analyses (PCA) were applied to the neural signals to reconstruct isometric forelimb forces. Computed regression coefficients were then used to predict isometric forces in additional trials. The correlation between measured and predicted forces in the vertical direction averaged across six animals was 0.67 and R2 value was 0.44. Force regression in the horizontal directions was less successful, possibly due to the small amplitude of forces. Neural signals above and near the high gamma band made the largest contributions to prediction of forces. The results of this study support the feasibility of a spinal cord computer interface (SCCI) for generation of command signals in paralyzed individuals.
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Affiliation(s)
- Yi Guo
- Department of Biomedical Engineering, New Jersey Institute of Technology Newark, NJ, USA
| | - Richard A Foulds
- Department of Biomedical Engineering, New Jersey Institute of Technology Newark, NJ, USA
| | - Sergei V Adamovich
- Department of Biomedical Engineering, New Jersey Institute of Technology Newark, NJ, USA
| | - Mesut Sahin
- Department of Biomedical Engineering, New Jersey Institute of Technology Newark, NJ, USA
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26
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The role of mesenchymal stromal cells in spinal cord injury, regenerative medicine and possible clinical applications. Biochimie 2013; 95:2257-70. [DOI: 10.1016/j.biochi.2013.08.004] [Citation(s) in RCA: 101] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2013] [Accepted: 08/05/2013] [Indexed: 12/13/2022]
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27
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Brazda N, Voss C, Estrada V, Lodin H, Weinrich N, Seide K, Müller J, Müller HW. A mechanical microconnector system for restoration of tissue continuity and long-term drug application into the injured spinal cord. Biomaterials 2013; 34:10056-64. [PMID: 24090837 DOI: 10.1016/j.biomaterials.2013.09.057] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2013] [Accepted: 09/17/2013] [Indexed: 11/18/2022]
Abstract
Complete transection of the spinal cord leaves a gap of several mm which fills with fibrous scar tissue. Several approaches in rodent models have used tubes, foams, matrices or tissue implants to bridge this gap. Here, we describe a mechanical microconnector system (mMS) to re-adjust the retracted spinal cord stumps. The mMS is a multi-channel system of polymethylmethacrylate (PMMA), designed to fit into the spinal cord tissue gap after transection, with an outlet tubing system to apply negative pressure to the mMS thus sucking the spinal cord stumps into the honeycomb-structured holes. The stumps adhere to the microstructure of the mMS walls and remain in the mMS after removal of the vacuum. We show that the mMS preserves tissue integrity and allows axonal regrowth at 2, 5 and 19 weeks post lesion with no adverse tissue effects like in-bleeding or cyst formation. Preliminary assessment of locomotor function in the open field suggested beneficial effects of the mMS. Additional inner micro-channels enable local substance delivery into the lesion center via an attached osmotic minipump. We suggest that the mMS is a suitable device to adapt and stabilize the injured spinal cord after surgical resection of scar tissue (e.g., for chronic patients) or traumatic injuries with large tissue and bone damages.
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Affiliation(s)
- Nicole Brazda
- Molecular Neurobiology Laboratory, Neurology, Heinrich Heine University Düsseldorf, Moorenstr. 5, 40225 Düsseldorf, Germany.
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28
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Synaptic elimination and protection after minimal injury depend on cell type and their prelesion structural dynamics in the adult cerebral cortex. J Neurosci 2013; 33:10374-83. [PMID: 23785150 DOI: 10.1523/jneurosci.0254-13.2013] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
The axonal and synaptic mechanisms underlying dysfunction and repair of the injured CNS are poorly understood. Unresolved issues include to what degree, when, and how the surviving neurons degenerate and the extent of synaptic remodeling both along the severed axon and in the nearby area. One of the main reasons is the lack of tools to study the complex asynchronous and dynamic features of individual lesioned axon responses in the intact brain. To address these issues, we combined two-photon microscopy and laser microsurgery to image the real-time reorganization of cortical circuitry at synaptic resolution for periods of up to 1 year in the brain of living mice. Injured cortical axons were eliminated proximally through a two-phase retraction process, which continued for at least 3 months postlesion and was independent of the presence of scar tissue. Remarkably, axons which later attempt to regenerate in both the mature and juvenile brain retracted less, raising the possibility that targeting retraction may improve the chances of axon regrowth after axotomy. Comparing prelesion and postlesion dynamics on the same axons over several days and weeks revealed that, although synapse formation rates were unaffected, boutons on injured axons were either rapidly and persistently lost, or extremely resistant, depending on cell-type and their prelesion structural dynamics. Our data suggest a lasting deficiency in synaptic output on surviving injured cortical axons and a surprising difference in the vulnerability of synaptic boutons after axotomy, which depend on cell-type and their recent history.
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29
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Wang X, Hu J, She Y, Smith GM, Xu XM. Cortical PKC inhibition promotes axonal regeneration of the corticospinal tract and forelimb functional recovery after cervical dorsal spinal hemisection in adult rats. Cereb Cortex 2013; 24:3069-79. [PMID: 23810979 DOI: 10.1093/cercor/bht162] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
Our previous study shows that conventional protein kinases C (cPKCs) are key signaling mediators that are activated by extracellular inhibitory molecules. Inhibition of cPKC by intrathecal infusion of a cPKC inhibitor, GÖ6976, into the site of dorsal hemisection (DH) induces regeneration of lesioned dorsal column sensory, but not corticospinal tract (CST), axons. Here, we investigated whether a direct cortical delivery of GÖ6976 into the soma of corticospinal neurons promotes regeneration of CST and the recovery of forelimb function in rats with cervical spinal cord injuries. We report that cortical delivery of GÖ6976 reduced injury-induced activation of conventional PKCα and PKCβ1 in CST neurons, promoted regeneration of CST axons through and beyond a cervical DH at C4, formed new synapses on target neurons caudal to the injury, and enhanced forelimb functional recovery in adult rats. When combined with lenti-Chondroitinase ABC treatment, cortical administration of GÖ6976 promoted even greater CST axonal regeneration and recovery of forelimb function. Thus, this study has demonstrated a novel strategy that can promote anatomical regeneration of damaged CST axons and partial recovery of forelimb function. Importantly, such an effect is critically dependent on the efficient blockage of injury-induced PKC activation in the soma of layer V CST neurons.
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Affiliation(s)
- Xiaofei Wang
- Spinal Cord and Brain Injury Research Group, Stark Neurosciences Research Institute, Department of Neurological Surgery, Indiana University School of Medicine, Indianapolis, IN 46202, USA and
| | - Jianguo Hu
- Spinal Cord and Brain Injury Research Group, Stark Neurosciences Research Institute, Department of Neurological Surgery, Indiana University School of Medicine, Indianapolis, IN 46202, USA and
| | - Yun She
- Spinal Cord and Brain Injury Research Group, Stark Neurosciences Research Institute, Department of Neurological Surgery, Indiana University School of Medicine, Indianapolis, IN 46202, USA and
| | - George M Smith
- Department of Physiology Spinal Cord and Brain Injury Research Center, University of Kentucky Chandler Medical Center, Lexington, KY 40636, USA
| | - Xiao-Ming Xu
- Spinal Cord and Brain Injury Research Group, Stark Neurosciences Research Institute, Department of Neurological Surgery, Indiana University School of Medicine, Indianapolis, IN 46202, USA and
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30
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González P, Fernández-Martos CM, Arenas E, Rodríguez FJ. The Ryk receptor is expressed in glial and fibronectin-expressing cells after spinal cord injury. J Neurotrauma 2013; 30:806-17. [PMID: 23320533 DOI: 10.1089/neu.2012.2613] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Wnt proteins play a critical role in central nervous system development and have been implicated in several neuropathologies, including spinal cord injury (SCI). Ryk, an unconventional Wnt receptor, regulates axonal regeneration after SCI, although its expression pattern in this neuropathology remains unclear. Therefore, we sought to define the spatiotemporal and cellular pattern of Ryk expression after a contusive SCI in adult rats using quantitative reverse transcription polymerase chain reaction (RT-PCR), Western blot, and immunohistochemical analysis. Under physiological conditions, Ryk is expressed in neurons, astrocytes, and blood vessels, but not in oligodendrocytes, microglia, NG2+ glial precursor cells, or axonal projections. Following SCI, we observed an increase in Ryk mRNA expression from 24 h post-injury until 7 days post-injury, whereas its protein levels were significantly augmented at 7 and 14 days post-injury. Moreover, the spatial and cellular Ryk expression pattern was altered in the damaged tissue, where this receptor was observed in reactive astrocytes and microglia/macrophages, NG2+ glial precursors, fibronectin+ cells, oligodendrocytes, and axons. In conclusion, we demonstrate that Ryk is expressed in the unlesioned spinal cord and that, after SCI, its spatiotemporal and cellular expression pattern changed dramatically, being expressed in cells involved in the spinal cord response to damage.
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Affiliation(s)
- Pau González
- Molecular Neurology Laboratory, Hospital Nacional de Paraplejicos-HNP, Toledo, Spain
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31
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Extensive respiratory plasticity after cervical spinal cord injury in rats: Axonal sprouting and rerouting of ventrolateral bulbospinal pathways. Exp Neurol 2012; 236:88-102. [DOI: 10.1016/j.expneurol.2012.04.004] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2011] [Revised: 03/14/2012] [Accepted: 04/11/2012] [Indexed: 01/10/2023]
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32
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Gonzenbach RR, Zoerner B, Schnell L, Weinmann O, Mir AK, Schwab ME. Delayed Anti-Nogo-A Antibody Application after Spinal Cord Injury Shows Progressive Loss of Responsiveness. J Neurotrauma 2012; 29:567-78. [DOI: 10.1089/neu.2011.1752] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Affiliation(s)
| | - Bjoern Zoerner
- Brain Research Institute, University of Zurich, Switzerland, Zürich, Switzerland
| | - Lisa Schnell
- Brain Research Institute, University of Zurich, Switzerland, Zürich, Switzerland
| | - Oliver Weinmann
- Brain Research Institute, University of Zurich, Switzerland, Zürich, Switzerland
| | | | - Martin E. Schwab
- University and ETH Zurich, University of Zurich, Switzerland, Zürich, Switzerland
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Farrar MJ, Bernstein IM, Schlafer DH, Cleland TA, Fetcho JR, Schaffer CB. Chronic in vivo imaging in the mouse spinal cord using an implanted chamber. Nat Methods 2012; 9:297-302. [PMID: 22266542 PMCID: PMC3429123 DOI: 10.1038/nmeth.1856] [Citation(s) in RCA: 122] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2011] [Accepted: 12/08/2011] [Indexed: 12/22/2022]
Abstract
Understanding and treatment of spinal cord pathology is limited in part by a lack of longitudinal in vivo imaging strategies at the cellular level. We developed a chronically implanted spinal chamber and surgical procedure suitable for time-lapse in vivo multiphoton microscopy of mouse spinal cord without the need for repeat surgical procedures. Repeated imaging was routinely achieved for more than five weeks post-operatively with up to ten separate imaging sessions. We observed neither motor function deficit nor neuropathology in the spinal cord as a result of chamber implantation. Using this chamber we quantified microglia and afferent axon dynamics following a laser-induced spinal cord lesion and observed massive microglia infiltration within one day along with a heterogeneous dieback of axon stumps. By enabling chronic imaging studies over timescales ranging from minutes to months, our method offers an ideal platform for understanding cellular dynamics in response to injury and therapeutic interventions.
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Affiliation(s)
- Matthew J Farrar
- Department of Physics, Cornell University, Ithaca, New York, USA
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34
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Yoshimura K, Ueno M, Lee S, Nakamura Y, Sato A, Yoshimura K, Kishima H, Yoshimine T, Yamashita T. c-Jun N-terminal kinase induces axonal degeneration and limits motor recovery after spinal cord injury in mice. Neurosci Res 2011; 71:266-77. [PMID: 21824499 DOI: 10.1016/j.neures.2011.07.1830] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2011] [Revised: 06/28/2011] [Accepted: 07/12/2011] [Indexed: 02/02/2023]
Abstract
c-Jun N-terminal kinase (JNK) mediates neuronal death in response to stress and injury in the CNS and peripheral nervous system. Here, we show that JNK also regulates retrograde axonal degeneration (axonal dieback) after spinal cord injury (SCI) in mice. Activated phospho-JNK was highly expressed in damaged corticospinal tract (CST) axons after thoracic SCI by hemisection. Local administration of SP600125, a JNK inhibitor, prevented accumulation of amyloid-β precursor protein and retraction of the severed CST axons as well as preserved the axonal arbors rostral to the injury site. The treatment with SP600125 also improved functional recovery of the hindlimbs, assessed by Basso mouse scale open-field scores and the grid-walking test. In Jnk1(-/-) and Jnk3(-/-) mice, we observed prevention of axonal degeneration and enhancement of motor recovery after SCI. These results indicate that both JNK1 and JNK3 induce axonal degeneration and limit motor recovery after SCI. Thus, a JNK inhibitor may be a suitable therapeutic agent for SCI.
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Affiliation(s)
- Kazuhiro Yoshimura
- Department of Molecular Neuroscience, Graduate School of Medicine, Osaka University, Suita-shi, Osaka, Japan
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35
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Multipotent adult progenitor cells prevent macrophage-mediated axonal dieback and promote regrowth after spinal cord injury. J Neurosci 2011; 31:944-53. [PMID: 21248119 DOI: 10.1523/jneurosci.3566-10.2011] [Citation(s) in RCA: 117] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Macrophage-mediated axonal dieback presents an additional challenge to regenerating axons after spinal cord injury. Adult adherent stem cells are known to have immunomodulatory capabilities, but their potential to ameliorate this detrimental inflammation-related process has not been investigated. Using an in vitro model of axonal dieback as well as an adult rat dorsal column crush model of spinal cord injury, we found that multipotent adult progenitor cells (MAPCs) can affect both macrophages and dystrophic neurons simultaneously. MAPCs significantly decrease MMP-9 (matrix metalloproteinase-9) release from macrophages, effectively preventing induction of axonal dieback. MAPCs also induce a shift in macrophages from an M1, or "classically activated" proinflammatory state, to an M2, or "alternatively activated" antiinflammatory state. In addition to these effects on macrophages, MAPCs promote sensory neurite outgrowth, induce sprouting, and further enable axons to overcome the negative effects of macrophages as well as inhibitory proteoglycans in their environment by increasing their intrinsic growth capacity. Our results demonstrate that MAPCs have therapeutic benefits after spinal cord injury and provide specific evidence that adult stem cells exert positive immunomodulatory and neurotrophic influences.
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36
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Quigley HA, Cone FE, Gelman SE, Yang Z, Son JL, Oglesby EN, Pease ME, Zack DJ. Lack of neuroprotection against experimental glaucoma in c-Jun N-terminal kinase 3 knockout mice. Exp Eye Res 2011; 92:299-305. [PMID: 21272576 DOI: 10.1016/j.exer.2011.01.006] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2010] [Revised: 12/21/2010] [Accepted: 01/18/2011] [Indexed: 01/09/2023]
Abstract
To determine if the absence of c-Jun N-terminal kinase 3 (JNK3) in the mouse retina would reduce retinal ganglion cell (RGC) loss in mice with experimental glaucoma. C57BL/6 mice underwent experimental intraocular pressure (IOP) elevation with a bead/viscoelastic injection into one eye. One-half of the mice were Jnk3 homozygous knockouts (KO) and were compared to wild type (WT) mice. IOP was measured under anesthesia with the TonoLab, axial length was measured post-mortem with calipers after inflation to 15mmHg, and RGC layer counts were performed on retinal whole mount images stained with DAPI, imaged by confocal microscopy, and counted by masked observers in an image analysis system. Axon counts were performed in optic nerve cross-sections by semi-automated image analysis. Both WT and Jnk3(-/-) mice had mean elevations of IOP of more than 50% after bead injection. Both groups underwent the expected axial globe elongation due to chronic IOP elevation. The absence of JNK3 in KO retina was demonstrated by Western blots. RGC layer neuron counts showed modest loss in both WT and Jnk3(-/-) animals; local differences by retinal eccentricity were detected, in each case indicating greater loss in KO animals than in WT. The baseline number of RGC layer cells in KO animals was 10% higher than in WT, but the number of optic nerve axons was identical in KO and WT controls. A slightly greater loss of RGC in Jnk3(-/-) mice compared to controls was detected in experimental mouse glaucoma by RGC layer counting and there was no protective effect shown in axon counts. Counts of RGC layer cells and optic nerve axons indicate that Jnk3(-/-) mice have an increased number of amacrine cells compared to WT controls.
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Affiliation(s)
- Harry A Quigley
- Glaucoma Research Laboratory, Wilmer Eye Institute, 600 North Wolfe Street, Johns Hopkins University School of Medicine, Baltimore, MD 21287-9205, USA.
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Zörner B, Schwab ME. Anti-Nogo on the go: from animal models to a clinical trial. Ann N Y Acad Sci 2010; 1198 Suppl 1:E22-34. [DOI: 10.1111/j.1749-6632.2010.05566.x] [Citation(s) in RCA: 147] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
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Synergistic effects of transplanted adult neural stem/progenitor cells, chondroitinase, and growth factors promote functional repair and plasticity of the chronically injured spinal cord. J Neurosci 2010; 30:1657-76. [PMID: 20130176 DOI: 10.1523/jneurosci.3111-09.2010] [Citation(s) in RCA: 292] [Impact Index Per Article: 20.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023] Open
Abstract
The transplantation of neural stem/progenitor cells (NPCs) is a promising therapeutic strategy for spinal cord injury (SCI). However, to date NPC transplantation has exhibited only limited success in the treatment of chronic SCI. Here, we show that chondroitin sulfate proteoglycans (CSPGs) in the glial scar around the site of chronic SCI negatively influence the long-term survival and integration of transplanted NPCs and their therapeutic potential for promoting functional repair and plasticity. We targeted CSPGs in the chronically injured spinal cord by sustained infusion of chondroitinase ABC (ChABC). One week later, the same rats were treated with transplants of NPCs and transient infusion of growth factors, EGF, bFGF, and PDGF-AA. We demonstrate that perturbing CSPGs dramatically optimizes NPC transplantation in chronic SCI. Engrafted NPCs successfully integrate and extensively migrate within the host spinal cord and principally differentiate into oligodendrocytes. Furthermore, this combined strategy promoted the axonal integrity and plasticity of the corticospinal tract and enhanced the plasticity of descending serotonergic pathways. These neuroanatomical changes were also associated with significantly improved neurobehavioral recovery after chronic SCI. Importantly, this strategy did not enhance the aberrant synaptic connectivity of pain afferents, nor did it exacerbate posttraumatic neuropathic pain. For the first time, we demonstrate key biological and functional benefits for the combined use of ChABC, growth factors, and NPCs to repair the chronically injured spinal cord. These findings could potentially bring us closer to the application of NPCs for patients suffering from chronic SCI or other conditions characterized by the formation of a glial scar.
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Brambilla R, Hurtado A, Persaud T, Esham K, Pearse DD, Oudega M, Bethea JR. Transgenic inhibition of astroglial NF-kappa B leads to increased axonal sparing and sprouting following spinal cord injury. J Neurochem 2009; 110:765-78. [PMID: 19522780 PMCID: PMC4090052 DOI: 10.1111/j.1471-4159.2009.06190.x] [Citation(s) in RCA: 92] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
We previously showed that Nuclear Factor kappaB (NF-kappaB) inactivation in astrocytes leads to improved functional recovery following spinal cord injury (SCI). This correlated with reduced expression of pro-inflammatory mediators and chondroitin sulfate proteoglycans, and increased white matter preservation. Hence we hypothesized that inactivation of astrocytic NF-kappaB would create a more permissive environment for axonal sprouting and regeneration. We induced both contusive and complete transection SCI in GFAP-Inhibitor of kappaB-dominant negative (GFAP-IkappaBalpha-dn) and wild-type (WT) mice and performed retrograde [fluorogold (FG)] and anterograde [biotinylated dextran amine (BDA)] tracing 8 weeks after injury. Following contusive SCI, more FG-labeled cells were found in motor cortex, reticular formation, and raphe nuclei of transgenic mice. Spared and sprouting BDA-positive corticospinal axons were found caudal to the lesion in GFAP-IkappaBalpha-dn mice. Higher numbers of FG-labeled neurons were detected immediately rostral to the lesion in GFAP-IkappaBalpha-dn mice, accompanied by increased expression of synaptic and axonal growth-associated molecules. After transection, however, no FG-labeled neurons or BDA-filled axons were found rostral and caudal to the lesion, respectively, in either genotype. These data demonstrated that inhibiting astroglial NF-kappaB resulted in a growth-supporting terrain promoting sparing and sprouting, rather than regeneration, of supraspinal and propriospinal circuitries essential for locomotion, hence contributing to the improved functional recovery observed after SCI in GFAP-IkappaBalpha-dn mice.
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Affiliation(s)
- Roberta Brambilla
- The Miami Project to Cure Paralysis, Department of Neurological Surgery, Miller School of Medicine, University of Miami, Miami, FL 33136
| | - Andres Hurtado
- International Center for Spinal Cord Injury, Hugo W. Moser Research Institute at Kennedy Krieger, Baltimore, MD 21205
| | - Trikaldarshi Persaud
- The Miami Project to Cure Paralysis, Department of Neurological Surgery, Miller School of Medicine, University of Miami, Miami, FL 33136
| | - Kim Esham
- The Miami Project to Cure Paralysis, Department of Neurological Surgery, Miller School of Medicine, University of Miami, Miami, FL 33136
| | - Damien D. Pearse
- The Miami Project to Cure Paralysis, Department of Neurological Surgery, Miller School of Medicine, University of Miami, Miami, FL 33136
- Neuroscience Program, Miller School of Medicine, University of Miami, Miami, FL 33136
| | - Martin Oudega
- Department of Physical Medicine and Rehabilitation and Neurobiology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15213
| | - John R. Bethea
- The Miami Project to Cure Paralysis, Department of Neurological Surgery, Miller School of Medicine, University of Miami, Miami, FL 33136
- Neuroscience Program, Miller School of Medicine, University of Miami, Miami, FL 33136
- Department of Microbiology and Immunology, Miller School of Medicine, University of Miami, Miami, FL 33136
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Another barrier to regeneration in the CNS: activated macrophages induce extensive retraction of dystrophic axons through direct physical interactions. J Neurosci 2008; 28:9330-41. [PMID: 18799667 DOI: 10.1523/jneurosci.2488-08.2008] [Citation(s) in RCA: 259] [Impact Index Per Article: 16.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
Injured axons of the adult CNS undergo lengthy retraction from the initial site of axotomy after spinal cord injury. Macrophage infiltration correlates spatiotemporally with this deleterious phenomenon, but the direct involvement of these inflammatory cells has not been demonstrated. In the present study, we examined the role of macrophages in axonal retraction within the dorsal columns after spinal cord injury in vivo and found that retraction occurred between days 2 and 28 after lesion and that the ends of injured axons were associated with ED-1+ cells. Clodronate liposome-mediated depletion of infiltrating macrophages resulted in a significant reduction in axonal retraction; however, we saw no evidence of regeneration. We used time-lapse imaging of adult dorsal root ganglion neurons in an in vitro model of the glial scar to examine macrophage-axon interactions and observed that adhesive contacts and considerable physical interplay between macrophages and dystrophic axons led to extensive axonal retraction. The induction of retraction was dependent on both the growth state of the axon and the activation state of the macrophage. Only dystrophic adult axons were susceptible to macrophage "attack." Unlike intrinsically active cell line macrophages, both primary macrophages and microglia required activation to induce axonal retraction. Contact with astrocytes had no deleterious effect on adult dystrophic axons, suggesting that the induction of extensive retraction was specific to phagocytic cells. Our data are the first to indicate a direct role of activated macrophages in axonal retraction by physical cell-cell interactions with injured axons.
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