Pain regulation by non-neuronal cells and inflammation. Ji Ru-Rong,Chamessian Alexander,Zhang Yu-Qiu Science (New York, N.Y.) Acute pain is protective and a cardinal feature of inflammation. Chronic pain after arthritis, nerve injury, cancer, and chemotherapy is associated with chronic neuroinflammation, a local inflammation in the peripheral or central nervous system. Accumulating evidence suggests that non-neuronal cells such as immune cells, glial cells, keratinocytes, cancer cells, and stem cells play active roles in the pathogenesis and resolution of pain. We review how non-neuronal cells interact with nociceptive neurons by secreting neuroactive signaling molecules that modulate pain. Recent studies also suggest that bacterial infections regulate pain through direct actions on sensory neurons, and specific receptors are present in nociceptors to detect danger signals from infections. We also discuss new therapeutic strategies to control neuroinflammation for the prevention and treatment of chronic pain. 10.1126/science.aaf8924
    Spinal-cord injury: Neural interfaces take another step forward. Jackson Andrew Nature 10.1038/539177a
    Regulation of Inflammatory Cytokines for Spinal Cord Injury Repair Through Local Delivery of Therapeutic Agents. Ren Hao,Chen Xuri,Tian Mengya,Zhou Jing,Ouyang Hongwei,Zhang Zhiyong Advanced science (Weinheim, Baden-Wurttemberg, Germany) The balance of inflammation is critical to the repair of spinal cord injury (SCI), which is one of the most devastating traumas in human beings. Inflammatory cytokines, the direct mediators of local inflammation, have differential influences on the repair of the injured spinal cord. Some inflammatory cytokines are demonstrated beneficial to spinal cord repair in SCI models, while some detrimental. Various animal researches have revealed that local delivery of therapeutic agents efficiently regulates inflammatory cytokines and promotes repair from SCI. Quite a few clinical studies have also shown the promotion of repair from SCI through regulation of inflammatory cytokines. However, local delivery of a single agent affects only a part of the inflammatory cytokines that need to be regulated. Meanwhile, different individuals have differential profiles of inflammatory cytokines. Therefore, future studies may aim to develop personalized strategies of locally delivered therapeutic agent cocktails for effective and precise regulation of inflammation, and substantial functional recovery from SCI. 10.1002/advs.201800529
    The translational landscape in spinal cord injury: focus on neuroplasticity and regeneration. Hutson Thomas H,Di Giovanni Simone Nature reviews. Neurology Over the past decade, we have witnessed a flourishing of novel strategies to enhance neuroplasticity and promote axon regeneration following spinal cord injury, and results from preclinical studies suggest that some of these strategies have the potential for clinical translation. Spinal cord injury leads to the disruption of neural circuitry and connectivity, resulting in permanent neurological disability. Recovery of function relies on augmenting neuroplasticity to potentiate sprouting and regeneration of spared and injured axons, to increase the strength of residual connections and to promote the formation of new connections and circuits. Neuroplasticity can be fostered by exploiting four main biological properties: neuronal intrinsic signalling, the neuronal extrinsic environment, the capacity to reconnect the severed spinal cord via neural stem cell grafts, and modulation of neuronal activity. In this Review, we discuss experimental evidence from rodents, nonhuman primates and patients regarding interventions that target each of these four properties. We then highlight the strengths and challenges of individual and combinatorial approaches with respect to clinical translation. We conclude by considering future developments and providing views on how to bridge the gap between preclinical studies and clinical translation. 10.1038/s41582-019-0280-3
    Locomotion dependent neuron-glia interactions control neurogenesis and regeneration in the adult zebrafish spinal cord. Chang Weipang,Pedroni Andrea,Bertuzzi Maria,Kizil Caghan,Simon András,Ampatzis Konstantinos Nature communications Physical exercise stimulates adult neurogenesis, yet the underlying mechanisms remain poorly understood. A fundamental component of the innate neuroregenerative capacity of zebrafish is the proliferative and neurogenic ability of the neural stem/progenitor cells. Here, we show that in the intact spinal cord, this plasticity response can be activated by physical exercise by demonstrating that the cholinergic neurotransmission from spinal locomotor neurons activates spinal neural stem/progenitor cells, leading to neurogenesis in the adult zebrafish. We also show that GABA acts in a non-synaptic fashion to maintain neural stem/progenitor cell quiescence in the spinal cord and that training-induced activation of neurogenesis requires a reduction of GABA receptors. Furthermore, both pharmacological stimulation of cholinergic receptors, as well as interference with GABAergic signaling, promote functional recovery after spinal cord injury. Our findings provide a model for locomotor networks' activity-dependent neurogenesis during homeostasis and regeneration in the adult zebrafish spinal cord. 10.1038/s41467-021-25052-1
    Transplanted neural stem/precursor cells instruct phagocytes and reduce secondary tissue damage in the injured spinal cord. Cusimano Melania,Biziato Daniela,Brambilla Elena,Donegà Matteo,Alfaro-Cervello Clara,Snider Silvia,Salani Giuliana,Pucci Ferdinando,Comi Giancarlo,Garcia-Verdugo Jose Manuel,De Palma Michele,Martino Gianvito,Pluchino Stefano Brain : a journal of neurology Transplanted neural stem/precursor cells possess peculiar therapeutic plasticity and can simultaneously instruct several therapeutic mechanisms in addition to cell replacement. Here, we interrogated the therapeutic plasticity of neural stem/precursor cells after their focal implantation in the severely contused spinal cord. We injected syngeneic neural stem/precursor cells at the proximal and distal ends of the contused mouse spinal cord and analysed locomotor functions and relevant secondary pathological events in the mice, cell fate of transplanted neural stem/precursor cells, and gene expression and inflammatory cell infiltration at the injured site. We used two different doses of neural stem/precursor cells and two treatment schedules, either subacute (7 days) or early chronic (21 days) neural stem/precursor cell transplantation after the induction of experimental thoracic severe spinal cord injury. Only the subacute transplant of neural stem/precursor cells enhanced the recovery of locomotor functions of mice with spinal cord injury. Transplanted neural stem/precursor cells survived undifferentiated at the level of the peri-lesion environment and established contacts with endogenous phagocytes via cellular-junctional coupling. This was associated with significant modulation of the expression levels of important inflammatory cell transcripts in vivo. Transplanted neural stem/precursor cells skewed the inflammatory cell infiltrate at the injured site by reducing the proportion of 'classically-activated' (M1-like) macrophages, while promoting the healing of the injured cord. We here identify a precise window of opportunity for the treatment of complex spinal cord injuries with therapeutically plastic somatic stem cells, and suggest that neural stem/precursor cells have the ability to re-programme the local inflammatory cell microenvironment from a 'hostile' to an 'instructive' role, thus facilitating the healing or regeneration past the lesion. 10.1093/brain/awr339
    Neural repair and rehabilitation: Prolonged neural stem cell maturation restores motor function in spinal cord-lesioned rats. Patel Mitesh Nature reviews. Neurology 10.1038/nrneurol.2017.133
    Designer, injectable gels to prevent transplanted Schwann cell loss during spinal cord injury therapy. Marquardt Laura M,Doulames Vanessa M,Wang Alice T,Dubbin Karen,Suhar Riley A,Kratochvil Michael J,Medress Zachary A,Plant Giles W,Heilshorn Sarah C Science advances Transplantation of patient-derived Schwann cells is a promising regenerative medicine therapy for spinal cord injuries; however, therapeutic efficacy is compromised by inefficient cell delivery. We present a materials-based strategy that addresses three common causes of transplanted cell death: (i) membrane damage during injection, (ii) cell leakage from the injection site, and (iii) apoptosis due to loss of endogenous matrix. Using protein engineering and peptide-based assembly, we designed injectable hydrogels with modular cell-adhesive and mechanical properties. In a cervical contusion model, our hydrogel matrix resulted in a greater than 700% improvement in successful Schwann cell transplantation. The combination therapy of cells and gel significantly improved the spatial distribution of transplanted cells within the endogenous tissue. A reduction in cystic cavitation and neuronal loss were also observed with substantial increases in forelimb strength and coordination. Using an injectable hydrogel matrix, therefore, can markedly improve the outcomes of cellular transplantation therapies. 10.1126/sciadv.aaz1039
    Stem-cell derived astrocytes promote repair of spinal cord. Love Rebecca The Lancet. Neurology 10.1016/s1474-4422(06)70460-4
    Stem cells: Targeting pain of spinal-cord injury. Nature 10.1038/537588d
    Cell therapy for spinal cord injury. Stower Hannah Nature medicine 10.1038/s41591-018-0155-y
    Decellularized peripheral nerve supports Schwann cell transplants and axon growth following spinal cord injury. Cerqueira Susana R,Lee Yee-Shuan,Cornelison Robert C,Mertz Michaela W,Wachs Rebecca A,Schmidt Christine E,Bunge Mary Bartlett Biomaterials Schwann cell (SC) transplantation has been comprehensively studied as a strategy for spinal cord injury (SCI) repair. SCs are neuroprotective and promote axon regeneration and myelination. Nonetheless, substantial SC death occurs post-implantation, which limits therapeutic efficacy. The use of extracellular matrix (ECM)-derived matrices, such as Matrigel, supports transplanted SC survival and axon growth, resulting in improved motor function. Because appropriate matrices are needed for clinical translation, we test here the use of an acellular injectable peripheral nerve (iPN) matrix. Implantation of SCs in iPN into a contusion lesion did not alter immune cell infiltration compared to injury only controls. iPN implants were larger and contained twice as many SC-myelinated axons as Matrigel grafts. SC/iPN animals performed as well as the SC/Matrigel group in the BBB locomotor test, and made fewer errors on the grid walk at 4 weeks, equalizing at 8 weeks. The fact that this clinically relevant iPN matrix is immunologically tolerated and supports SC survival and axon growth within the graft offers a highly translational possibility for improving efficacy of SC treatment after SCI. To our knowledge, it is the first time that an injectable PN matrix is being evaluated to improve the efficacy of SC transplantation in SCI repair. 10.1016/j.biomaterials.2018.05.049
    Mitochondrial Transfer from Bone Marrow Mesenchymal Stem Cells to Motor Neurons in Spinal Cord Injury Rats via Gap Junction. Li Heyangzi,Wang Chao,He Teng,Zhao Tengfei,Chen Ying-Ying,Shen Yue-Liang,Zhang Xiaoming,Wang Lin-Lin Theranostics Recent studies have demonstrated that bone marrow mesenchymal stem cells (BMSCs) protect the injured neurons of spinal cord injury (SCI) from apoptosis while the underlying mechanism of the protective effect of BMSCs remains unclear. In this study, we found the transfer of mitochondria from BMSCs to injured motor neurons and detected the functional improvement after transplanting. Primary rat BMSCs were co-cultured with oxygen-glucose deprivation (OGD) injured VSC4.1 motor neurons or primary cortical neurons. FACS analysis was used to detect the transfer of mitochondria from BMSCs to neurons. The bioenergetics profiling of neurons was detected by Extracellular Flux Analysis. Cell viability and apoptosis were also measured. BMSCs and isolated mitochondria were transplanted into SCI rats. TdT-mediated dUTP nick end labelling staining was used to detect apoptotic neurons in the ventral horn. Immunohistochemistry and Western blotting were used to measure protein expression. Re-myelination was examined by transmission electron microscope. BBB scores were used to assess locomotor function. MitoTracker-Red labelled mitochondria of BMSCs could be transferred to the OGD injured neurons. The gap junction intercellular communication (GJIC) potentiator retinoid acid increased the quantity of mitochondria transfer from BMSCs to neurons, while GJIC inhibitor 18β glycyrrhetinic acid decreased mitochondria transfer. Internalization of mitochondria improved the bioenergetics profile, decreased apoptosis and promoted cell survival in post-OGD motor neurons. Furthermore, both transplantation of mitochondria and BMSCs to the injured spinal cord improved locomotor functional recovery in SCI rats. To our knowledge, this is the first evidence that BMSCs protect against SCI through GJIC to transfer mitochondrial to the injured neurons. Our findings suggested a new therapy strategy of mitochondria transfer for the patients with SCI. 10.7150/thno.29400
    Therapeutic Efficacy-Potentiated and Diseased Organ-Targeting Nanovesicles Derived from Mesenchymal Stem Cells for Spinal Cord Injury Treatment. Kim Han Young,Kumar Hemant,Jo Min-Jae,Kim Jonghoon,Yoon Jeong-Kee,Lee Ju-Ro,Kang Mikyung,Choo Yeon Woong,Song Seuk Young,Kwon Sung Pil,Hyeon Taeghwan,Han In-Bo,Kim Byung-Soo Nano letters Human mesenchymal stem cell (hMSC)-derived exosomes have been spotlighted as a promising therapeutic agent for cell-free regenerative medicine. However, poor organ-targeting ability and insufficient therapeutic efficacy of systemically injected hMSC-exosomes were identified as critical limitations for their further applications. Therefore, in this study we fabricated iron oxide nanoparticle (IONP)-incorporated exosome-mimetic nanovesicles (NV-IONP) from IONP-treated hMSCs and evaluated their therapeutic efficacy in a clinically relevant model for spinal cord injury. Compared to exosome-mimetic nanovesicles (NV) prepared from untreated hMSCs, NV-IONP not only contained IONPs which act as a magnet-guided navigation tool but also carried greater amounts of therapeutic growth factors that can be delivered to the target cells. The increased amounts of therapeutic growth factors inside NV-IONP were attributed to IONPs that are slowly ionized to iron ions which activate the JNK and c-Jun signaling cascades in hMSCs. In vivo systemic injection of NV-IONP with magnetic guidance significantly increased the amount of NV-IONP accumulating in the injured spinal cord. Accumulated NV-IONP enhanced blood vessel formation, attenuated inflammation and apoptosis in the injured spinal cord, and consequently improved spinal cord function. Taken together, these findings highlight the development of therapeutic efficacy-potentiated extracellular nanovesicles and demonstrate their feasibility for repairing injured spinal cord. 10.1021/acs.nanolett.8b01816
    Small molecules combined with collagen hydrogel direct neurogenesis and migration of neural stem cells after spinal cord injury. Yang Yaming,Fan Yongheng,Zhang Haipeng,Zhang Qi,Zhao Yannan,Xiao Zhifeng,Liu Wenbin,Chen Bing,Gao Lin,Sun Zheng,Xue Xiaoyu,Shu Muya,Dai Jianwu Biomaterials Complete spinal cord injury (SCI) leads to cell death, interruption of axonal connections and permanent functional impairments. In the development of SCI treatments, cell transplantation combined with biomaterial-growth factor-based therapies have been widely studied. Another avenue worth exploring is the generation of neurons from endogenous neural stem cells (NSCs) or reactive astrocytes activated by SCI. Here, we screened a combination of four small molecules, LDN193189, SB431542, CHIR99021 and P7C3-A20, that can increase neuronal differentiation of mouse and rat spinal cord NSCs. Moreover, the small molecules loaded in an injectable collagen hydrogel induced neurogenesis and inhibited astrogliogenesis of endogenous NSCs in the injury site, which usually differentiate into astrocytes under pathological conditions. Meanwhile, induced neurons migrated into the non-neural lesion core, and genetic fate mapping showed that neurons mainly originated from NSCs in the parenchyma, but not from the central canal of the spinal cord. The neuronal regeneration in the lesion sites resulted in some recovery of locomotion. Our findings indicate that the combined treatment of small molecules and collagen hydrogel is a potential therapeutic strategy for SCI by inducing in situ endogenous NSCs to form neurons and restore damaged functions. 10.1016/j.biomaterials.2020.120479
    Cell biology of spinal cord injury and repair. O'Shea Timothy M,Burda Joshua E,Sofroniew Michael V The Journal of clinical investigation Spinal cord injury (SCI) lesions present diverse challenges for repair strategies. Anatomically complete injuries require restoration of neural connectivity across lesions. Anatomically incomplete injuries may benefit from augmentation of spontaneous circuit reorganization. Here, we review SCI cell biology, which varies considerably across three different lesion-related tissue compartments: (a) non-neural lesion core, (b) astrocyte scar border, and (c) surrounding spared but reactive neural tissue. After SCI, axon growth and circuit reorganization are determined by neuron-cell-autonomous mechanisms and by interactions among neurons, glia, and immune and other cells. These interactions are shaped by both the presence and the absence of growth-modulating molecules, which vary markedly in different lesion compartments. The emerging understanding of how SCI cell biology differs across lesion compartments is fundamental to developing rationally targeted repair strategies. 10.1172/JCI90608
    Treatment of spinal cord injury by an advanced cell transplantation technology using brain-derived neurotrophic factor-transfected mesenchymal stem cell spheroids. Uchida Satoshi,Hayakawa Kentaro,Ogata Toru,Tanaka Sakae,Kataoka Kazunori,Itaka Keiji Biomaterials Curing spinal cord injury (SCI) is challenging because of the onset of multiple and irreversible pathological responses to such injury. To suppress the responses, we employed an advanced cell transplantation technology integrating three-dimensional spheroid cell transplantation with non-viral gene transfection using biodegradable polycations. Brain-derived neurotrophic factor (BDNF)-transfected mesenchymal stem cell (MSC) spheroids were transplanted at thoraces level (Th9) to SCI region in mice. BDNF-transfected MSC spheroid transplantation led to a significantly enhanced recovery of hindlimb motor function in acute phase of SCI with myelinated axons preserved at the SCI region, while use of either technology in isolation, BDNF transfection or spheroid culture, exerted only a limited therapeutic effect, demonstrating the importance of integrated approaches. Secretion of endogenous therapeutic proteins, such as anti-inflammatory factors, was greater in MSC spheroids than in monolayer culture MSCs, and these factors appeared to act synergistically alongside BDNF secretion in SCI treatment. This study forms a basis for cell therapy regulating complex pathophysiologic processes. 10.1016/j.biomaterials.2016.09.007
    3D Printed Stem-Cell Derived Neural Progenitors Generate Spinal Cord Scaffolds. Joung Daeha,Truong Vincent,Neitzke Colin C,Guo Shuang-Zhuang,Walsh Patrick J,Monat Joseph R,Meng Fanben,Park Sung Hyun,Dutton James R,Parr Ann M,McAlpine Michael C Advanced functional materials A bioengineered spinal cord is fabricated via extrusion-based multi-material 3D bioprinting, in which clusters of induced pluripotent stem cell (iPSC)-derived spinal neuronal progenitor cells (sNPCs) and oligodendrocyte progenitor cells (OPCs) are placed in precise positions within 3D printed biocompatible scaffolds during assembly. The location of a cluster of cells, of a single type or multiple types, is controlled using a point-dispensing printing method with a 200 μm center-to-center spacing within 150 μm wide channels. The bioprinted sNPCs differentiate and extend axons throughout microscale scaffold channels, and the activity of these neuronal networks is confirmed by physiological spontaneous calcium flux studies. Successful bioprinting of OPCs in combination with sNPCs demonstrates a multicellular neural tissue engineering approach, where the ability to direct the patterning and combination of transplanted neuronal and glial cells can be beneficial in rebuilding functional axonal connections across areas of central nervous system (CNS) tissue damage. This platform can be used to prepare novel biomimetic, hydrogel-based scaffolds modeling complex CNS tissue architecture and harnessed to develop new clinical approaches to treat neurological diseases, including spinal cord injury. 10.1002/adfm.201801850
    Combined polymer-curcumin conjugate and ependymal progenitor/stem cell treatment enhances spinal cord injury functional recovery. Requejo-Aguilar Raquel,Alastrue-Agudo Ana,Cases-Villar Marta,Lopez-Mocholi Eric,England Richard,Vicent María J,Moreno-Manzano Victoria Biomaterials Spinal cord injury (SCI) suffers from a lack of effective therapeutic strategies. Animal models of acute SCI have provided evidence that transplantation of ependymal stem/progenitor cells of the spinal cord (epSPCs) induces functional recovery, while systemic administration of the anti-inflammatory curcumin provides neuroprotection. However, functional recovery from chronic stage SCI requires additional enhancements in available therapeutic strategies. Herein, we report on a combination treatment for SCI using epSPCs and a pH-responsive polymer-curcumin conjugate. The incorporation of curcumin in a pH-responsive polymeric carrier mainchain, a polyacetal (PA), enhances blood bioavailability, stability, and provides a means for highly localized delivery. We find that PA-curcumin enhances neuroprotection, increases axonal growth, and can improve functional recovery in acute SCI. However, when combined with epSPCs, PA-curcumin also enhances functional recovery in a rodent model of chronic SCI. This suggests that combination therapy may be an exciting new therapeutic option for the treatment of chronic SCI in humans. 10.1016/j.biomaterials.2016.10.032
    Resident neural stem cells restrict tissue damage and neuronal loss after spinal cord injury in mice. Sabelström Hanna,Stenudd Moa,Réu Pedro,Dias David O,Elfineh Marta,Zdunek Sofia,Damberg Peter,Göritz Christian,Frisén Jonas Science (New York, N.Y.) Central nervous system injuries are accompanied by scar formation. It has been difficult to delineate the precise role of the scar, as it is made by several different cell types, which may limit the damage but also inhibit axonal regrowth. We show that scarring by neural stem cell-derived astrocytes is required to restrict secondary enlargement of the lesion and further axonal loss after spinal cord injury. Moreover, neural stem cell progeny exerts a neurotrophic effect required for survival of neurons adjacent to the lesion. One distinct component of the glial scar, deriving from resident neural stem cells, is required for maintaining the integrity of the injured spinal cord. 10.1126/science.1242576
    Current Options for Cell Therapy in Spinal Cord Injury. Vismara Irma,Papa Simonetta,Rossi Filippo,Forloni Gianluigi,Veglianese Pietro Trends in molecular medicine Spinal cord injury (SCI) is a complex pathology that evolves after primary acute mechanical injury, causing further damage to the spinal cord tissue that exacerbates clinical outcomes. Based on encouraging results from preclinical experiments, some cell treatments being translated into clinical practice demonstrate promising and effective improvement in sensory/motor function. Combinatorial treatments of cell and drug/biological factors have been demonstrated to be more effective than cell treatments alone. Recent advances have led to the development of biomaterials aiming to promote in situ cell delivery for SCI, together with combinatorial strategies using drugs/biomolecules to achieve a maximized multitarget approach. This review provides an overview of single and combinatorial regenerative cell treatments as well as potential delivery options to treat SCI. 10.1016/j.molmed.2017.07.005
    Transplanted Human Stem Cell-Derived Interneuron Precursors Mitigate Mouse Bladder Dysfunction and Central Neuropathic Pain after Spinal Cord Injury. Fandel Thomas M,Trivedi Alpa,Nicholas Cory R,Zhang Haoqian,Chen Jiadong,Martinez Aida F,Noble-Haeusslein Linda J,Kriegstein Arnold R Cell stem cell Neuropathic pain and bladder dysfunction represent significant quality-of-life issues for many spinal cord injury patients. Loss of GABAergic tone in the injured spinal cord may contribute to the emergence of these symptoms. Previous studies have shown that transplantation of rodent inhibitory interneuron precursors from the medial ganglionic eminence (MGE) enhances GABAergic signaling in the brain and spinal cord. Here we look at whether transplanted MGE-like cells derived from human embryonic stem cells (hESC-MGEs) can mitigate the pathological effects of spinal cord injury. We find that 6 months after transplantation into injured mouse spinal cords, hESC-MGEs differentiate into GABAergic neuron subtypes and receive synaptic inputs, suggesting functional integration into host spinal cord. Moreover, the transplanted animals show improved bladder function and mitigation of pain-related symptoms. Our results therefore suggest that this approach may be a valuable strategy for ameliorating the adverse effects of spinal cord injury. 10.1016/j.stem.2016.08.020
    Human neuroepithelial stem cell regional specificity enables spinal cord repair through a relay circuit. Dell'Anno Maria Teresa,Wang Xingxing,Onorati Marco,Li Mingfeng,Talpo Francesca,Sekine Yuichi,Ma Shaojie,Liu Fuchen,Cafferty William B J,Sestan Nenad,Strittmatter Stephen M Nature communications Traumatic spinal cord injury results in persistent disability due to disconnection of surviving neural elements. Neural stem cell transplantation has been proposed as a therapeutic option, but optimal cell type and mechanistic aspects remain poorly defined. Here, we describe robust engraftment into lesioned immunodeficient mice of human neuroepithelial stem cells derived from the developing spinal cord and maintained in self-renewing adherent conditions for long periods. Extensive elongation of both graft and host axons occurs. Improved functional recovery after transplantation depends on neural relay function through the grafted neurons, requires the matching of neural identity to the anatomical site of injury, and is accompanied by expression of specific marker proteins. Thus, human neuroepithelial stem cells may provide an anatomically specific relay function for spinal cord injury recovery. 10.1038/s41467-018-05844-8
    Cell transplantation therapies for spinal cord injury focusing on induced pluripotent stem cells. Nakamura Masaya,Okano Hideyuki Cell research Stimulated by the 2012 Nobel Prize in Physiology or Medicine awarded for Shinya Yamanaka and Sir John Gurdon, there is an increasing interest in the induced pluripotent stem (iPS) cells and reprograming technologies in medical science. While iPS cells are expected to open a new era providing enormous opportunities in biomedical sciences in terms of cell therapies and regenerative medicine, safety-related concerns for iPS cell-based cell therapy should be resolved prior to the clinical application of iPS cells. In this review, the pre-clinical investigations of cell therapy for spinal cord injury (SCI) using neural stem/progenitor cells derived from iPS cells, and their safety issues in vivo, are outlined. We also wish to discuss the strategy for the first human trails of iPS cell-based cell therapy for SCI patients. 10.1038/cr.2012.171
    Role of endogenous neural stem cells in spinal cord injury and repair. Stenudd Moa,Sabelström Hanna,Frisén Jonas JAMA neurology Spinal cord injury is followed by glial scar formation, which has positive and negative effects on recovery from the lesion. More than half of the astrocytes in the glial scar are generated by ependymal cells, the neural stem cells in the spinal cord. We recently demonstrated that the neural stem cell-derived scar component has several beneficial functions, including restricting tissue damage and neural loss after spinal cord injury. This finding identifies endogenous neural stem cells as a potential therapeutic target for treatment of spinal cord injury. 10.1001/jamaneurol.2014.2927
    Cell transplantation therapy for spinal cord injury. Assinck Peggy,Duncan Greg J,Hilton Brett J,Plemel Jason R,Tetzlaff Wolfram Nature neuroscience Spinal cord injury can lead to severe motor, sensory and autonomic dysfunction. Currently, there is no effective treatment for the injured spinal cord. The transplantation of Schwann cells, neural stem cells or progenitor cells, olfactory ensheathing cells, oligodendrocyte precursor cells and mesenchymal stem cells has been investigated as potential therapies for spinal cord injury. However, little is known about the mechanisms through which these individual cell types promote repair and functional improvements. The five most commonly proposed mechanisms include neuroprotection, immunomodulation, axon regeneration, neuronal relay formation and myelin regeneration. A better understanding of the mechanisms whereby these cells promote functional improvements, as well as an appreciation of the obstacles in implementing these therapies and effectively modeling spinal cord injury, will be important to make cell transplantation a viable clinical option and may lead to the development of more targeted therapies. 10.1038/nn.4541
    Mesenchymal Stem Cells in Treatment of Spinal Cord Injury and Amyotrophic Lateral Sclerosis. Sykova Eva,Cizkova Dasa,Kubinova Sarka Frontiers in cell and developmental biology Preclinical and clinical studies with various stem cells, their secretomes, and extracellular vesicles (EVs) indicate their use as a promising strategy for the treatment of various diseases and tissue defects, including neurodegenerative diseases such as spinal cord injury (SCI) and amyotrophic lateral sclerosis (ALS). Autologous and allogenic mesenchymal stem cells (MSCs) are so far the best candidates for use in regenerative medicine. Here we review the effects of the implantation of MSCs (progenitors of mesodermal origin) in animal models of SCI and ALS and in clinical studies. MSCs possess multilineage differentiation potential and are easily expandable . These cells, obtained from bone marrow (BM), adipose tissue, Wharton jelly, or even other tissues, have immunomodulatory and paracrine potential, releasing a number of cytokines and factors which inhibit the proliferation of T cells, B cells, and natural killer cells and modify dendritic cell activity. They are hypoimmunogenic, migrate toward lesion sites, induce better regeneration, preserve perineuronal nets, and stimulate neural plasticity. There is a wide use of MSC systemic application or MSCs seeded on scaffolds and tissue bridges made from various synthetic and natural biomaterials, including human decellularized extracellular matrix (ECM) or nanofibers. The positive effects of MSC implantation have been recorded in animals with SCI lesions and ALS. Moreover, promising effects of autologous as well as allogenic MSCs for the treatment of SCI and ALS were demonstrated in recent clinical studies. 10.3389/fcell.2021.695900
    Current Concepts of Stem Cell Therapy for Chronic Spinal Cord Injury. Suzuki Hidenori,Sakai Takashi International journal of molecular sciences Chronic spinal cord injury (SCI) is a catastrophic condition associated with significant neurological deficit and social and financial burdens. It is currently being managed symptomatically with no real therapeutic strategies available. In recent years, a number of innovative regenerative strategies have emerged and have been continuously investigated in clinical trials. In addition, several more are coming down the translational pipeline. Among ongoing and completed trials are those reporting the use of mesenchymal stem cells, neural stem/progenitor cells, induced pluripotent stem cells, olfactory ensheathing cells, and Schwann cells. The advancements in stem cell technology, combined with the powerful neuroimaging modalities, can now accelerate the pathway of promising novel therapeutic strategies from bench to bedside. Various combinations of different molecular therapies have been combined with supportive scaffolds to facilitate favorable cell-material interactions. In this review, we summarized some of the most recent insights into the preclinical and clinical studies using stem cells and other supportive drugs to unlock the microenvironment in chronic SCI to treat patients with this condition. Successful future therapies will require these stem cells and other synergistic approaches to address the persistent barriers to regeneration, including glial scarring, loss of structural framework, and immunorejection. 10.3390/ijms22147435
    The Emerging Role of Exosomes in the Treatment of Human Disorders With a Special Focus on Mesenchymal Stem Cells-Derived Exosomes. Ghafouri-Fard Soudeh,Niazi Vahid,Hussen Bashdar Mahmud,Omrani Mir Davood,Taheri Mohammad,Basiri Abbas Frontiers in cell and developmental biology Extracellular vesicles (EVs) are produced by diverse eukaryotic and prokaryotic cells. They have prominent roles in the modulation of cell-cell communication, inflammation versus immunomodulation, carcinogenic processes, cell proliferation and differentiation, and tissue regeneration. These acellular vesicles are more promising than cellular methods because of the lower risk of tumor formation, autoimmune responses and toxic effects compared with cell therapy. Moreover, the small size and lower complexity of these vesicles compared with cells have made their production and storage easier than cellular methods. Exosomes originated from mesenchymal stem cells has also been introduced as therapeutic option for a number of human diseases. The current review aims at summarization of the role of EVs in the regenerative medicine with a focus on their therapeutic impacts in liver fibrosis, lung disorders, osteoarthritis, colitis, myocardial injury, spinal cord injury and retinal injury. 10.3389/fcell.2021.653296
    Elucidating the Pivotal Neuroimmunomodulation of Stem Cells in Spinal Cord Injury Repair. Richard Seidu A,Sackey Marian Stem cells international Spinal cord injury (SCI) is a distressing incident with abrupt onset of the motor as well as sensory dysfunction, and most often, the injury occurs as result of high-energy or velocity accidents as well as contact sports and falls in the elderly. The key challenges associated with nerve repair are the lack of self-repair as well as neurotrophic factors and primary and secondary neuronal apoptosis, as well as factors that prevent the regeneration of axons locally. Neurons that survive the initial traumatic damage may be lost due to pathogenic activities like neuroinflammation and apoptosis. Implanted stem cells are capable of differentiating into neural cells that replace injured cells as well as offer local neurotrophic factors that aid neuroprotection, immunomodulation, axonal sprouting, axonal regeneration, and remyelination. At the microenvironment of SCI, stem cells are capable of producing growth factors like brain-derived neurotrophic factor and nerve growth factor which triggers neuronal survival as well as axonal regrowth. Although stem cells have proven to be of therapeutic value in SCI, the major disadvantage of some of the cell types is the risk for tumorigenicity due to the contamination of undifferentiated cells prior to transplantation. Local administration of stem cells via either direct cellular injection into the spinal cord parenchyma or intrathecal administration into the subarachnoid space is currently the best transplantation modality for stem cells during SCI. 10.1155/2021/9230866
    Combination of Drugs and Cell Transplantation: More Beneficial Stem Cell-Based Regenerative Therapies Targeting Neurological Disorders. Nishimura Kaneyasu,Takata Kazuyuki International journal of molecular sciences Cell transplantation therapy using pluripotent/multipotent stem cells has gained attention as a novel therapeutic strategy for treating neurodegenerative diseases, including Parkinson's disease, Alzheimer's disease, Huntington's disease, ischemic stroke, and spinal cord injury. To fully realize the potential of cell transplantation therapy, new therapeutic options that increase cell engraftments must be developed, either through modifications to the grafted cells themselves or through changes in the microenvironment surrounding the grafted region. Together these developments could potentially restore lost neuronal function by better supporting grafted cells. In addition, drug administration can improve the outcome of cell transplantation therapy through better accessibility and delivery to the target region following cell transplantation. Here we introduce examples of drug repurposing approaches for more successful transplantation therapies based on preclinical experiments with clinically approved drugs. Drug repurposing is an advantageous drug development strategy because drugs that have already been clinically approved can be repurposed to treat other diseases faster and at lower cost. Therefore, drug repurposing is a reasonable approach to enhance the outcomes of cell transplantation therapies for neurological diseases. Ideal repurposing candidates would result in more efficient cell transplantation therapies and provide a new and beneficial therapeutic combination. 10.3390/ijms22169047
    An Overview of Mesenchymal Stem Cell-based Therapy Mediated by Noncoding RNAs in the Treatment of Neurodegenerative Diseases. Luo Yifei,Qiu Wei,Wu Buling,Fang Fuchun Stem cell reviews and reports Mesenchymal stem cells (MSCs) have become a promising tool for neurorestorative therapy of neurodegenerative diseases (NDDs), which are mainly characterized by the progressive and irreversible loss of neuronal structure and function in the central or peripheral nervous system. Recently, studies have reported that genetic manipulation mediated by noncoding RNAs (ncRNAs) can increase survival and neural regeneration of transplanted MSCs, offering a new strategy for clinical translation. In this review, we summarize the potential role and regulatory mechanism of two major types of ncRNAs, including microRNAs (miRNAs) and long noncoding RNAs (lncRNAs), during the neurogenesis of MSCs with gene expression profile analyses. We also overview the realization of MSC-based therapy mediated by ncRNAs in the treatment of spinal cord injury, stroke, Alzheimer's disease and peripheral nerve injury. It is expected that ncRNAs will become promising therapeutic targets for NDD on stem cells, while the underlying mechanisms require further exploration. 10.1007/s12015-021-10206-x
    [Research progress of hydrogel combined with mesenchymal stem cells in the treatment of spinal cord injury]. Yuan Xin,Ding Lu,Deng David Y B Sheng wu yi xue gong cheng xue za zhi = Journal of biomedical engineering = Shengwu yixue gongchengxue zazhi Spinal cord injury (SCI) is a complex pathological process. Based on the encouraging results of preclinical experiments, some stem cell therapies have been translated into clinical practice. Mesenchymal stem cells (MSCs) have become one of the most important seed cells in the treatment of SCI due to their abundant sources, strong proliferation ability and low immunogenicity. However, the survival rate of MSCs transplanted to spinal cord injury is rather low, which hinders its further clinical application. In recent years, hydrogel materials have been widely used in tissue engineering because of their good biocompatibility and biodegradability. The treatment strategy of hydrogel combined with MSCs has made some progress in SCI repair. This review discusses the significance and the existing problems of MSCs in the repair of SCI. It also describes the research progress of hydrogel combined with MSCs in repairing SCI, and prospects its application in clinical research, aiming at providing reference and new ideas for future SCI treatment. 10.7507/1001-5515.202005055
    Oxygen-glucose deprivation in neurons: implications for cell transplantation therapies. Rizzo Sebastiano Antonio,Bartley Oliver,Rosser Anne E,Newland Ben Progress in neurobiology Cell replacement therapies hold the potential to restore neuronal networks compromised by neurodegenerative diseases (such as Parkinson's disease or Huntington's disease), or focal tissue damage (via a stroke or spinal cord injury). Despite some promising results achieved to date, transplanted cells typically exhibit poor survival in the central nervous system, thus limiting therapeutic efficacy of the graft. Although cell death post-transplantation is likely to be multifactorial in causality, growing evidence suggests that the lack of vascularisation at the graft site, and the resulting ischemic host environment, may play a fundamental role in the fate of grafted cells. Herein, we summarise data showing how the deprivation of either oxygen, glucose, or both in combination, impacts the survival of neurons and review strategies which may improve graft survival in the central nervous system. 10.1016/j.pneurobio.2021.102126
    A review of emerging neuroprotective and neuroregenerative therapies in traumatic spinal cord injury. Hejrati Nader,Fehlings Michael G Current opinion in pharmacology Traumatic spinal cord injuries (SCIs) have far-reaching physical, social, and financial consequences. While medical advancements have improved supportive therapeutic measures for SCI patients, no effective neuroregenerative therapeutic options exist to date. Instead, the paradigm of SCI therapy is inevitably directed towards damage control rather than the restoration of a state of functional independence. Facing a continuous increase in the prevalence of spinal cord injured patients, neuroprotective and neuroregenerative strategies have earned tremendous scientific interest. This review intends to provide a robust summary of the most promising neuroprotective and neuroregenerative therapies currently under investigation. While we highlight encouraging neuroprotective strategies as well, the focus of this review lies on neuroregenerative therapies, including neuropharmacological and cell-based approaches. We finally point to the exciting investigational areas of biomaterial scaffolds and neuromodulation therapies. 10.1016/j.coph.2021.08.009
    Delving into the recent advancements of spinal cord injury treatment: a review of recent progress. Flack Joseph A,Sharma Krishna Deo,Xie Jennifer Yanhua Neural regeneration research Spinal cord injury (SCI) research is a very complex field lending to why reviews of SCI literatures can be beneficial to current and future researchers. This review focuses on recent articles regarding potential modalities for the treatment and management of SCI. The modalities were broken down into four categories: neuroprotection-pharmacologic, neuroprotection-non-pharmacologic, neuroregeneration-pharmacologic, neuroregeneration-non-pharmacologic. Peer-reviewed articles were found using PubMed with search terms: "spinal cord injury", "spinal cord injury neuroregeneration", "olfactory ensheathing cells spinal cord injury", "rho-rock inhibitors spinal cord injury", "neural stem cell", "scaffold", "neural stem cell transplantation", "exosomes and SCI", "epidural stimulation SCI", "brain-computer interfaces and SCI". Most recent articles spanning two years were chosen for their relevance to the categories of SCI management and treatment. There has been a plethora of pre-clinical studies completed with their results being difficult to replicate in clinical studies. Therefore, scientists should focus on understanding and applying the results of previous research to develop more efficacious preclinical studies and clinical trials. 10.4103/1673-5374.317961