Neural Stem Cell Transplantation Promotes Functional Recovery from Traumatic Brain Injury via Brain Derived Neurotrophic Factor-Mediated Neuroplasticity

Human-Induced Pluripotent Stem Cell-Derived Neural Stem Cell Therapy Limits Tissue Damage and Promotes Tissue Regeneration and Functional Recovery in a Pediatric Piglet Traumatic-Brain-Injury Model

Traumatic brain injury (TBI) is a leading cause of death and disability in pediatric patients and often results in delayed neural development and altered connectivity, leading to lifelong learning, memory, behavior, and motor function deficits. Induced pluripotent stem cell-derived neural stem cells (iNSCs) may serve as a novel multimodal therapeutic as iNSCs possess neuroprotective, regenerative, and cell-replacement capabilities post-TBI. In this study, we evaluated the effects of iNSC treatment on cellular, tissue, and functional recovery in a translational controlled cortical impact TBI piglet model. Five days post-craniectomy (n = 6) or TBI (n = 18), iNSCs (n = 7) or PBS (n = 11) were injected into perilesional brain tissue. Modified Rankin Scale (mRS) neurological evaluation, magnetic resonance imaging, and immunohistochemistry were performed over the 12-week study period. At 12-weeks post-transplantation, iNSCs showed long-term engraftment and differentiation into neurons, astrocytes, and oligodendrocytes. iNSC treatment enhanced endogenous neuroprotective and regenerative activities indicated by decreasing intracerebral immune responses, preserving endogenous neurons, and increasing neuroblast formation. These cellular changes corresponded with decreased hemispheric atrophy, midline shift, and lesion volume as well as the preservation of cerebral blood flow. iNSC treatment increased piglet survival and decreased mRS scores. The results of this study in a predictive pediatric large-animal pig model demonstrate that iNSC treatment is a robust multimodal therapeutic that has significant promise in potentially treating human pediatric TBI patients.

Neural stem cells promote neuroplasticity: a promising therapeutic strategy for the treatment of Alzheimer's disease

Recent studies have demonstrated that neuroplasticity, such as synaptic plasticity and neurogenesis, exists throughout the normal lifespan but declines with age and is significantly impaired in individuals with Alzheimer's disease. Hence, promoting neuroplasticity may represent an effective strategy with which Alzheimer's disease can be alleviated. Due to their significant ability to self-renew, differentiate, and migrate, neural stem cells play an essential role in reversing synaptic and neuronal damage, reducing the pathology of Alzheimer's disease, including amyloid-β, tau protein, and neuroinflammation, and secreting neurotrophic factors and growth factors that are related to plasticity. These events can promote synaptic plasticity and neurogenesis to repair the microenvironment of the mammalian brain. Consequently, neural stem cells are considered to represent a potential regenerative therapy with which to improve Alzheimer's disease and other neurodegenerative diseases. In this review, we discuss how neural stem cells regulate neuroplasticity and optimize their effects to enhance their potential for treating Alzheimer's disease in the clinic.

Neurotrophins and neural stem cells in posttraumatic brain injury repair

Traumatic brain injury (TBI) is the main cause of disability, mental health disorder, and even death, with its incidence and social costs rising steadily. Although different treatment strategies have been developed and tested to mitigate neurological decline, a definitive cure for these conditions remains elusive. Studies have revealed that various neurotrophins represented by the brain-derived neurotrophic factor are the key regulators of neuroinflammation, apoptosis, blood-brain barrier permeability, neurite regeneration, and memory function. These factors are instrumental in alleviating neuroinflammation and promoting neuroregeneration. In addition, neural stem cells (NSC) contribute to nerve repair through inherent neuroprotective and immunomodulatory properties, the release of neurotrophins, the activation of endogenous NSCs, and intercellular signaling. Notably, innovative research proposals are emerging to combine BDNF and NSCs, enabling them to synergistically complement and promote each other in facilitating injury repair and improving neuron differentiation after TBI. In this review, we summarize the mechanism of neurotrophins in promoting neurogenesis and restoring neural function after TBI, comprehensively explore the potential therapeutic effects of various neurotrophins in basic research on TBI, and investigate their interaction with NSCs. This endeavor aims to provide a valuable insight into the clinical treatment and transformation of neurotrophins in TBI, thereby promoting the progress of TBI therapeutics.

Neural Stem Cells Transplanted into Rhesus Monkey Cortical Traumatic Brain Injury Can Survive and Differentiate into Neurons

Cortical traumatic brain injury (TBI) is a major cause of cognitive impairment accompanied by motor and behavioral deficits, and there is no effective treatment strategy in the clinic. Cell transplantation is a promising therapeutic strategy, and it is necessary to verify the survival and differentiation of cells after transplantation in large animal models like rhesus monkeys. In this study, we transplanted neural stem cells (NSCs) and simultaneously injected basic fibroblast growth factor/epidermal growth factor (bFGF/EGF) into the cortex (visual and sensory cortices) of rhesus monkeys with superficial TBI. The results showed that the transplanted NSCs did not enter the cerebrospinal fluid (CSF) and were confined to the transplantation site for at least one year. The transplanted NSCs differentiated into mature neurons that formed synaptic connections with host neurons, but glial scar formation between the graft and the host tissue did not occur. This study is the first to explore the repairing effect of transplanting NSCs into the superficial cerebral cortex of rhesus monkeys after TBI, and the results show the ability of NSCs to survive long-term and differentiate into neurons, demonstrating the potential of NSC transplantation for cortical TBI.

Extracellular Vesicles: Therapeutic Potential in Central Nervous System Trauma by Regulating Cell Death

CNS (central nervous system) trauma, which is classified as SCI (spinal cord injury) and TBI (traumatic brain injury), is gradually becoming a major cause of accidental death and disability worldwide. Many previous studies have verified that the pathophysiological mechanism underlying cell death and the subsequent neuroinflammation caused by cell death are pivotal factors in the progression of CNS trauma. Simultaneously, EVs (extracellular vesicles), membrane-enclosed particles produced by almost all cell types, have been proven to mediate cell-to-cell communication, and cell death involves complex interactions among molecules. EVs have also been proven to be effective carriers of loaded bioactive components to areas of CNS trauma. Therefore, EVs are promising therapeutic targets to cure CNS trauma. However, the link between EVs and various types of cell death in the context of CNS trauma remains unknown. Therefore, in this review, we summarize the mechanism underlying EV effects, the relationship between EVs and cell death and the pathophysiology underlying EV effects on the CNS trauma based on information in published papers. In addition, we discuss the prospects of applying EVs to the CNS as feasible therapeutic strategies for CNS trauma in the future.

mNSCs overexpressing Rimkla transplantation facilitates cognitive recovery in a mouse model of traumatic brain injury

N-acetyl aspartyl-glutamate (NAAG) is easily inactivated for the hydrolysis of NAAG peptidase on the surface of glial cells, thereby losing its endogenous neuroprotective effect after traumatic brain injury. In this study, lentiviral vectors were used to over express/knock out NAAG synthetase II (Rimkla) in mouse embryonic neural stem cells (mNSCs) in vitro and these mNSCs were transplanted at the lesion site in a mouse model of controlled cortical impact (CCI). In vivo experiments showed that transplantation of mNSCs overexpressing Rimkla regulated glutamate-glutamine cycling between adjacent astrocytes and neurons in the subacute phase of CCI, thereby enhancing support for neuronal metabolism and promoting neuronal synaptic repair in the hippocampal CA3 region. Taken together, these findings demonstrate that transplantation of neural stem cells overexpressing Rimkla can effectively increase the NAAG concentration in local brain regions, which opens up new ideas for the maintenance of NAAG neuroprotective effects after TBI.

Genetically engineered neural stem cells (NSCs) therapy for neurological diseases; state-of-the-art

Neural stem cells (NSCs) are multipotent stem cells with remarkable self-renewal potential and also unique competencies to differentiate into neurons, astrocytes, and oligodendrocytes (ODCs) and improve the cellular microenvironment. In addition, NSCs secret diversity of mediators, including neurotrophic factors (e.g., BDNF, NGF, GDNF, CNTF, and NT-3), pro-angiogenic mediators (e.g., FGF-2 and VEGF), and anti-inflammatory biomolecules. Thereby, NSCs transplantation has become a reasonable and effective treatment for various neurodegenerative disorders by their capacity to induce neurogenesis and vasculogenesis and dampen neuroinflammation and oxidative stress. Nonetheless, various drawbacks such as lower migration and survival and less differential capacity to a particular cell lineage concerning the disease pathogenesis hinder their application. Thus, genetic engineering of NSCs before transplantation is recently regarded as an innovative strategy to bypass these hurdles. Indeed, genetically modified NSCs could bring about more favored therapeutic influences post-transplantation in vivo, making them an excellent option for neurological disease therapy. This review for the first time offers a comprehensive review of the therapeutic capability of genetically modified NSCs rather than naïve NSCs in neurological disease beyond brain tumors and sheds light on the recent progress and prospect in this context.

GABAergic neurons differentiated from BDNF- and Dlx2-modified neural stem cells restore disrupted neural circuits in brainstem stroke

BACKGROUND

Brainstem stroke causes severe and persistent neurological impairment. Due to the limited spontaneous recovery and regeneration of the disrupted neural circuits, transplantation of exogenous neural stem cells (NSCs) was an alternative, while there were limitations for primitive NSCs.

METHODS

We established a mouse model of brainstem stroke by injecting endothelin in the right pons. Brain-derived neurotrophic factor (BDNF)- and distal-less homeobox 2 (Dlx2)-modified NSCs were transplanted to treat brainstem stroke. Transsynaptic viral tracking, immunostaining, magnetic resonance imaging, behavioral testing, and whole-cell patch clamp recordings were applied to probe the pathophysiology and therapeutic prospects of BDNF- and Dlx2-modified NSCs.

RESULTS

GABAergic neurons were predominantly lost after the brainstem stroke. No endogenous NSCs were generated in situ or migrated from the neurogenesis niches within the brainstem infarct region. Co-overexpressions of BDNF and Dlx2 not only promoted the survival of NSCs, but also boosted the differentiation of NSCs into GABAergic neurons. Results from transsynaptic virus tracking, immunostaining, and evidence from whole-cell patch clamping revealed the morphological and functional integration of the grafted BDNF- and Dlx2-modified NSCs-derived neurons with the host neural circuits. Neurological function was improved by transplantation of BDNF- and Dlx2-modified NSCs in brainstem stroke.

CONCLUSIONS

These findings demonstrated that BDNF- and Dlx2-modified NSCs differentiated into GABAergic neurons, integrated into and reconstituted the host neural networks, and alleviated the ischemic injury. It thus provided a potential therapeutic strategy for brainstem stroke.

Exosomes and Nano-SDF Scaffold as a Cell-Free-Based Treatment Strategy Improve Traumatic Brain Injury Mechanisms by Decreasing Oxidative Stress, Neuroinflammation, and Increasing Neurogenesis

Traumatic brain injury (TBI) causes a variety of complex pathological changes in brain parenchymal tissue by increasing neuroinflammatory and apoptosis responses. Currently, there is no treatment to resolve the consequences related to TBI. Recently, an extensive literature has grown up around the theme of bystander effects of stem cells, a mechanism of stem cells without the need for cell transplantation, which is called cell-free therapy. The purpose of this investigation was to determine the efficacy of a cell-free-based therapy strategy using exosomes derived from human neural stem cells (hNSCs) and a novel nano-scaffold in rats subjected to TBI. In this study, a series of in vitro and in vivo experiments from behavior tests to gene expression was performed to define the effect of exosomes in combination with a three-dimensional (3D) nano-scaffold containing a bio-motif of SDF1α (Nano-SDF). Application of exosomes with Nano-SDF significantly decreased oxidative stress in serum and brain samples. Moreover, treatment with exosomes and Nano-SDF significantly reduced the expression of Toll-like receptor 4 and its downstream signaling pathway, including NF-kβ and interleukin-1β. We also found that the cell-free-based therapy strategy could decrease reactive gliosis at the injury site. Interestingly, we showed that exosomes with Nano-SDF increased neurogenesis in the sub-ventricular zone of the lateral ventricle, indicating a bio-bridge mechanism. To sum up, the most obvious finding to emerge from this study is that a cell-free-based therapy strategy can be an effective option for future practice in the course of TBI.

Traumatic Brain Injury and Secondary Neurodegenerative Disease

Traumatic brain injury (TBI) is a devastating event with severe long-term complications. TBI and its sequelae are one of the leading causes of death and disability in those under 50 years old. The full extent of secondary brain injury is still being intensely investigated; however, it is now clear that neurotrauma can incite chronic neurodegenerative processes. Chronic traumatic encephalopathy, Parkinson's disease, and many other neurodegenerative syndromes have all been associated with a history of traumatic brain injury. The complex nature of these pathologies can make clinical assessment, diagnosis, and treatment challenging. The goal of this review is to provide a concise appraisal of the literature with focus on emerging strategies to improve clinical outcomes. First, we review the pathways involved in the pathogenesis of neurotrauma-related neurodegeneration and discuss the clinical implications of this rapidly evolving field. Next, because clinical evaluation and neuroimaging are essential to the diagnosis and management of neurodegenerative diseases, we analyze the clinical investigations that are transforming these areas of research. Finally, we briefly review some of the preclinical therapies that have shown the most promise in improving outcomes after neurotrauma.

Porous Silicon Nanoparticles Targeted to the Extracellular Matrix for Therapeutic Protein Delivery in Traumatic Brain Injury

Traumatic brain injury (TBI) is a major cause of disability and death among children and young adults in the United States, yet there are currently no treatments that improve the long-term brain health of patients. One promising therapeutic for TBI is brain-derived neurotrophic factor (BDNF), a protein that promotes neurogenesis and neuron survival. However, outstanding challenges to the systemic delivery of BDNF are its instability in blood, poor transport into the brain, and short half-life in circulation and brain tissue. Here, BDNF is encapsulated into an engineered, biodegradable porous silicon nanoparticle (pSiNP) in order to deliver bioactive BDNF to injured brain tissue after TBI. The pSiNP carrier is modified with the targeting ligand CAQK, a peptide that binds to extracellular matrix components upregulated after TBI. The protein cargo retains bioactivity after release from the pSiNP carrier, and systemic administration of the CAQK-modified pSiNPs results in effective delivery of the protein cargo to injured brain regions in a mouse model of TBI. When administered after injury, the CAQK-targeted pSiNP delivery system for BDNF reduces lesion volumes compared to free BDNF, supporting the hypothesis that pSiNPs mediate therapeutic protein delivery after systemic administration to improve outcomes in TBI.

Alginate hydrogel cross-linked by Ca2+ to promote spinal cord neural stem/progenitor cell differentiation and functional recovery after a spinal cord injury

Alginate capillary hydrogels seeded with differentiated cells can fill the lesion cavity and promote axonal regeneration after grafting into the injured spinal cord. Neural stem/progenitor cells (NSPCs) can potentially repair the spinal cord; however, effects of alginate hydrogels (AHs) on NSPCs remain unknown. In this study, we fabricated AHs cross-linked by Ca²⁺ and seeded hydrogels with rat embryonic day 14 NSPCs. Immunocytochemistry and electron microscopy show that NSPCs survive, proliferate and differentiate into neurons in vitro within the capillaries. After transplantation into an acute T8 complete spinal cord transection site in adult rats, approximately one-third (38.3%) of grafted cells survive and differentiate into neurons (40.7%), astrocytes (26.6%) and oligodendrocytes (28.4%) at 8 weeks post-grafting. NSPCs promote the growth of host axons within the capillaries in a time-dependent manner. Host axons make synapse-like contacts with NSPC-derived neurons within the hydrogel channels, and graft-derived axons extend into the host white and gray matter making putative synapses. This is paralleled by improved electrophysiological conductivity across the lesion and partial hindlimb locomotor recovery.

Application of extracorporeal shock wave therapy in nervous system diseases: A review

Neurological disorders are one of the leading causes of morbidity and mortality worldwide, and their therapeutic options remain limited. Recent animal and clinical studies have shown the potential of extracorporeal shock wave therapy (ESWT) as an innovative, safe, and cost-effective option to treat neurological disorders. Moreover, the cellular and molecular mechanism of ESWT has been proposed to better understand the regeneration and repairment of neurological disorders by ESWT. In this review, we discuss the principles of ESWT, the animal and clinical studies involving the use of ESWT to treat central and peripheral nervous system diseases, and the proposed cellular and molecular mechanism of ESWT. We also discuss the challenges encountered when applying ESWT to the human brain and spinal cord and the new potential applications of ESWT in treating neurological disorders.

Exosome Derived from Human Neural Stem Cells Improves Motor Activity and Neurogenesis in a Traumatic Brain Injury Model

Traumatic brain injury (TBI) is a leading cause of mortality and long-lasting disability globally. Although novel treatment options have been investigated, no effective therapeutic opportunities for TBI exist. Accumulating studies demonstrated that the paracrine mechanisms of stem cells may allow them to orchestrate regenerative processes after TBI. So far, very little attention has been paid to the beneficial effects of human neural stem cells (hNSCs) in comparison to their exosomes as a paracrine mechanism. This study is aimed at comparing the effect of hNSCs with their exosomes in a TBI model. For in vitro assessments, we cultured hNSCs using the neurosphere method and isolated hNSC-derived exosomes from culture supernatants. For in vivo experiments, male rats were divided into three groups (n = 8/group): TBI group: rats were subjected to a unilateral mild cortical impact; hNSC group: rats received a single intralesional injection of 2 × 10⁶ hNSCs after TBI; and exosome group: rats received a single intralesional injection of 63 μg protein of hNSC-derived exosomes after TBI. Neurological assessments, neuroinflammation, and neurogenesis were performed at the predetermined time points after TBI. Our results indicated that the administration of exosomes improved the neurobehavioral performance measured by the modified neurological severity score (mNSS) on day 28 after TBI. Furthermore, exosomes inhibited the expression of reactive astrocytes as a key regulator of neuroinflammation marked by GFAP at the protein level, while enhancing the expression of Doublecortin (DCX) as a neurogenesis marker at the mRNA level. On the other hand, we observed that the expression of stemness markers (SOX2 and Nestin) was elevated in the hNSC group compared to the exosome and TBI groups. To sum up, our results demonstrated that the superior effects of exosomes versus parent hNSCs could be mediated by improving mNSS score and increasing DCX in TBI. Considerably, more work will need to be done to determine the beneficial effects of exosomes versus parent cells in the context of TBI.

Brain injury environment critically influences the connectivity of transplanted neurons

Cell transplantation is a promising approach for the reconstruction of neuronal circuits after brain damage. Transplanted neurons integrate with remarkable specificity into circuitries of the mouse cerebral cortex affected by neuronal ablation. However, it remains unclear how neurons perform in a local environment undergoing reactive gliosis, inflammation, macrophage infiltration, and scar formation, as in traumatic brain injury (TBI). To elucidate this, we transplanted cells from the embryonic mouse cerebral cortex into TBI-injured, inflamed-only, or intact cortex of adult mice. Brain-wide quantitative monosynaptic rabies virus (RABV) tracing unraveled graft inputs from correct regions across the brain in all conditions, with pronounced quantitative differences: scarce in intact and inflamed brain versus exuberant after TBI. In the latter, the initial overshoot is followed by pruning, with only a few input neurons persisting at 3 months. Proteomic profiling identifies candidate molecules for regulation of the synaptic yield, a pivotal parameter to tailor for functional restoration of neuronal circuits.

Neural stem cell secretome exerts a protective effect on damaged neuron mitochondria in Parkinson's disease model

Parkinson's disease (PD) is a common neurodegenerative disease. The main pathological changes are the loss of dopaminergic neurons and the formation of Lewy bodies. There is still no effective cure for PD, and cell replacement therapy has entered a bottleneck period due to tumorigenicity and rejection. Therefore, stem cell secretome has received widespread attention. However, the exploration of the secretome components of neural stem cells (NSCs) is still in its infancy. In this study, 6-hydroxydopamine (6-OHDA) was used to establish a PD rat model in vito and the PC12 cell-damaged model in vitro. The results indicated that the injection of neural stem cell-conditioned medium (NSC-CM) into the striatum and substantia nigra could improve the motor and non-motor deficits of PD rats and rescue the loss of dopaminergic neurons. In addition, NSC-CM alleviated 6-OHDA-induced apoptosis of PC12 cells, reduced the level of oxidative stress, and improved mitochondrial dysfunction in vitro. Parkinson disease protein 7 (Park7) was found in NSC-CM by Liquid chromatography-tandem mass spectrometry (LC-MS/MS), and it may be related to the protective effect of NSC-CM on 6-OHDA-injured neurons through Sirt1 pathway. In conclusion, NSC secretome might provide new ideas for the treatment of PD.

Brain Extract of Subacute Traumatic Brain Injury Promotes the Neuronal Differentiation of Human Neural Stem Cells via Autophagy

Background: After a traumatic brain injury (TBI), the cell environment is dramatically changed, which has various influences on grafted neural stem cells (NSCs). At present, these influences on NSCs have not been fully elucidated, which hinders the finding of an optimal timepoint for NSC transplantation. Methods: Brain extracts of TBI mice were used in vitro to simulate the different phase TBI influences on the differentiation of human NSCs. Protein profiles of brain extracts were analyzed. Neuronal differentiation and the activation of autophagy and the WNT/CTNNB pathway were detected after brain extract treatment. Results: Under subacute TBI brain extract conditions, the neuronal differentiation of hNSCs was significantly higher than that under acute brain extract conditions. The autophagy flux and WNT/CTNNB pathway were activated more highly within the subacute brain extract than in the acute brain extract. Autophagy activation by rapamycin could rescue the neuronal differentiation of hNSCs within acute TBI brain extract. Conclusions: The subacute phase around 7 days after TBI in mice could be a candidate timepoint to encourage more neuronal differentiation after transplantation. The autophagy flux played a critical role in regulating neuronal differentiation of hNSCs and could serve as a potential target to improve the efficacy of transplantation in the early phase.

Cell cycle exit and neuronal differentiation 1-engineered embryonic neural stem cells enhance neuronal differentiation and neurobehavioral recovery after experimental traumatic brain injury

Our previous study showed that cell cycle exit and neuronal differentiation 1 (CEND1) may participate in neural stem cell cycle exit and oriented differentiation. However, whether CEND1-transfected neural stem cells can improve the prognosis of traumatic brain injury remained unclear. In this study, we performed quantitative proteomic analysis and found that after traumatic brain injury, CEND1 expression was downregulated in mouse brain tissue. Three days after traumatic brain injury, we transplanted CEND1-transfected neural stem cells into the area surrounding the injury site. We found that at 5 weeks after traumatic brain injury, transplantation of CEND1-transfected neural stem cells markedly alleviated brain atrophy and greatly improved neurological function. In vivo and in vitro results indicate that CEND1 overexpression inhibited the proliferation of neural stem cells, but significantly promoted their neuronal differentiation. Additionally, CEND1 overexpression reduced protein levels of Notch1 and cyclin D1, but increased levels of p21 in CEND1-transfected neural stem cells. Treatment with CEND1-transfected neural stem cells was superior to similar treatment without CEND1 transfection. These findings suggest that transplantation of CEND1-transfected neural stem cells is a promising cell therapy for traumatic brain injury. This study was approved by the Animal Ethics Committee of the School of Biomedical Engineering of Shanghai Jiao Tong University, China (approval No. 2016034) on November 25, 2016.

The Roles of Neurotrophins in Traumatic Brain Injury

Neurotrophins are a collection of structurally and functionally related proteins. They play important roles in many aspects of neural development, survival, and plasticity. Traumatic brain injury (TBI) leads to different levels of central nervous tissue destruction and cellular repair through various compensatory mechanisms promoted by the injured brain. Many studies have shown that neurotrophins are key modulators of neuroinflammation, apoptosis, blood–brain barrier permeability, memory capacity, and neurite regeneration. The expression of neurotrophins following TBI is affected by the severity of injury, genetic polymorphism, and different post-traumatic time points. Emerging research is focused on the potential therapeutic applications of neurotrophins in managing TBI. We conducted a comprehensive review by organizing the studies that demonstrate the role of neurotrophins in the management of TBI.

Neural stem cell delivery using brain-derived tissue-specific bioink for recovering from traumatic brain injury

Traumatic brain injury is one of the leading causes of accidental death and disability. The loss of parts in a severely injured brain induces edema, neuronal apoptosis, and neuroinflammation. Recently, stem cell transplantation demonstrated regenerative efficacy in an injured brain. However, the efficacy of current stem cell therapy needs improvement to resolve issues such as low survival of implanted stem cells and low efficacy of differentiation into respective cells. We developed brain-derived decellularized extracellular matrix (BdECM) bioink that is printable and has native brain-like stiffness. This study aimed to fabricate injured cavity-fit scaffold with BdECM bioink and assessed the utility of BdECM bioink for stem cell delivery to a traumatically injured brain. Our BdECM bioink had shear thinning property for three-dimensional (3D)-cell-printing and physical properties and fiber structures comparable to those of the native brain, which is important for tissue integration after implantation. The human neural stem cells (NSCs) (F3 cells) laden with BdECM bioink were found to be fully differentiated to neurons; the levels of markers for mature differentiated neurons were higher than those observed with collagen bioinkin vitro. Moreover, the BdECM bioink demonstrated potential in defect-fit carrier fabrication with 3D cell-printing, based on the rheological properties and shape fidelity of the material. As F3 cell-laden BdECM bioink was transplanted into the motor cortex of a rat brain, high efficacy of differentiation into mature neurons was observed in the transplanted NSCs; notably increased level of MAP2, a marker of neuronal differentiation, was observed. Furthermore, the transplanted-cell bioink suppressed reactive astrogliosis and microglial activation that may impede regeneration of the injured brain. The brain-specific material reported here is favorable for NSC differentiation and suppression of neuroinflammation and is expected to successfully support regeneration of a traumatically injured brain.

Long term neuroprotective effects of acute single dose MK-801treatment against traumatic brain injury in immature rats

Because brain development continues during adolescence, childhood trauma is a major health problem in pediatric ages. It is known traumatic brain injury (TBI) results in damage in hippocampal and cortical areas of the brain and impairs cognitive functions. The study aims to investigate the long-term effects of MK-801 (dizocilpine), an N-methyl d-aspartate (NMDA) receptor antagonist, on hippocampal damage, locomotor activity, and cognitive functions following TBI in immature rats. MK-801 (1 mg/kg) was injected intraperitoneally immediately after TBI. Thirty-seven litters were randomly allocated into three groups at 7 days (P7) of postnatal age: a control group, a trauma group, and an MK-801 treatment group. The control group received no treatment; the trauma group received saline as vehicle control for the MK-801 group and the MK-801 group received a single dose of 1 mg/kg MK-801 immediately after TBI. Hippocampal damage was examined by Hematoxylin-Eosin staining. Brain-derived neurotrophic factor (BDNF), nerve growth factor (NGF), NMDA-R, and glial fibrillar acidic protein (GFAP) immunohistochemistry and, BDNF, NGF, and NMDA-R ELISA protein levels were evaluated 125 days after trauma. Histopathological and immunohistochemical evaluations showed that treatment with MK-801 significantly ameliorated the trauma-induced hippocampal neuron loss and increased BDNF, NGF, NMDA-R, GFAP expressions in CA1, CA3, and DG hippocampal regions. Additionally, treatment with MK-801 decreased anxiety and increased hippocampus-dependent memory of animals subjected to brain injury after TBI. These results show that acute treatment of MK-801 has a neuroprotective role against trauma-induced hippocampal neuron loss and associated cognitive impairment in rats.

An implantable human stem cell-derived tissue-engineered rostral migratory stream for directed neuronal replacement

The rostral migratory stream (RMS) facilitates neuroblast migration from the subventricular zone to the olfactory bulb throughout adulthood. Brain lesions attract neuroblast migration out of the RMS, but resultant regeneration is insufficient. Increasing neuroblast migration into lesions has improved recovery in rodent studies. We previously developed techniques for fabricating an astrocyte-based Tissue-Engineered RMS (TE-RMS) intended to redirect endogenous neuroblasts into distal brain lesions for sustained neuronal replacement. Here, we demonstrate that astrocyte-like-cells can be derived from adult human gingiva mesenchymal stem cells and used for TE-RMS fabrication. We report that key proteins enriched in the RMS are enriched in TE-RMSs. Furthermore, the human TE-RMS facilitates directed migration of immature neurons in vitro. Finally, human TE-RMSs implanted in athymic rat brains redirect migration of neuroblasts out of the endogenous RMS. By emulating the brain’s most efficient means for directing neuroblast migration, the TE-RMS offers a promising new approach to neuroregenerative medicine.

O’Donnell et al. describe their Tissue-Engineered Rostral Migratory Stream (TE-RMS) comprised of human astrocyte-like cells that can be derived from adult gingival stem cells within one week, which reorganizes into bundles of bidirectional, longitudinally-aligned astrocytes to emulate the endogenous RMS. Establishing immature neuronal migration in vitro and in vivo, their study demonstrates surgical feasibility and proof-of-concept evidence for this nascent technology.

Cell-Based Therapies for Traumatic Brain Injury: Therapeutic Treatments and Clinical Trials

Traumatic brain injury (TBI) represents physical damage to the brain tissue that induces transitory or permanent neurological disabilities. TBI contributes to 50% of all trauma deaths, with many enduring long-term consequences and significant medical and rehabilitation costs. There is currently no therapy to reverse the effects associated with TBI. An increasing amount of research has been undertaken regarding the use of different stem cells (SCs) to treat the consequences of brain damage. Neural stem cells (NSCs) (adult and embryonic) and mesenchymal stromal cells (MSCs) have shown efficacy in pre-clinical models of TBI and in their introduction to clinical research. The purpose of this review is to provide an overview of TBI and the state of clinical trials aimed at evaluating the use of stem cell-based therapies in TBI. The primary aim of these studies is to investigate the safety and efficacy of the use of SCs to treat this disease. Although an increasing number of studies are being carried out, few results are currently available. In addition, we present our research regarding the use of cell therapy in TBI. There is still a significant lack of understanding regarding the cell therapy mechanisms for the treatment of TBI. Thus, future studies are needed to evaluate the feasibility of the transplantation of SCs in TBI.

The Rotary Cell Culture System increases NTRK3 expression and promotes neuronal differentiation and migratory ability of neural stem cells cultured on collagen sponge

Background

Recently, neural stem cell (NSC) therapy has shown promise for the treatment of many neurological diseases. Enhancing the quality of implanted cells and improving therapeutic efficacy are currently research hotspots. It has been reported that collagen sponge material provided sufficient room for cell growth in all directions and promoted the absorption of nutrients and removal of wastes. And also, the Rotary Cell Culture System (RCCS), which mimics the microgravity environment, can be used to culture cells for tissue engineering.

Materials and methods

We performed the mRNA and miRNA sequencing to elucidate the regulatory mechanism of NSCs cultured on the collagen sponge in the RCCS system. The luciferase assay and Western blot revealed a direct regulatory role between let-7i-5p and neurotrophic receptor tyrosine kinase 3 (NTRK3; also called TrkC). And then, the neural differentiation markers Tuj1 and Map2 were detected by immunofluorescence staining. In the meantime, the migratory ability of NSCs was detected both in vitro and in spinal cord injury animals.

Results

In this study, we demonstrated that the expression of NTRK3 was elevated in NSCs cultured on collagen sponge in the RCCS system. Furthermore, increased NTRK3 expression was regulated by the downregulation of let-7i-5p. Compared to traditionally cultured NSCs, the NSCs cultured on collagen sponge in the RCCS system exhibited better neuronal differentiation and migratory ability, especially in the presence of NT-3.

Conclusions

As the biological properties and quality of transplanted cells are critical for therapeutic success, the RCCS system combined with the collagen sponge culture system shows promise for applications in clinical practice in the future.

Transplantation of Human Cortically-Specified Neuroepithelial Progenitor Cells Leads to Improved Functional Outcomes in a Mouse Model of Stroke

Stroke is a leading cause of death and long-term disability worldwide. Current therapeutic options are limited in terms of their time for implementation and efficacy in promoting recovery. Cell transplantation has been shown to have promise in several animal models however significant challenges remain, including the optimal source of cells to promote neural repair. Here, we report on the use of a population of human ESC derived, cortically specified, neuroepithelial precursor cells (cNEPs) that are neurally restricted in their lineage potential. CNEPs have the potential to give rise to mature neural cell types following transplantation, including neurons, astrocytes and oligodendrocytes. With a view towards translation, we sought to determine whether this human cell source was effective in promoting improved functional outcomes following stroke. Undifferentiated cNEPs were transplanted in a pre-clinical endothelin-1 (ET-1) model of ischemic motor cortical stroke in immunocompromised SCID-beige mice and cellular and functional outcomes were assessed. We demonstrate that cNEP transplantation in the acute phase (4 days post-stroke) improves motor function as early as 20 days post-stroke, compared to stroke-injured, non-transplanted mice. At the time of recovery, a small fraction (<6%) of the transplanted cNEPs are observed within the stroke injury site. The surviving cells expressed the immature neuronal marker, doublecortin, with no differentiation into mature neural phenotypes. At longer survival times (40 days), the majority of recovered, transplanted mice had a complete absence of surviving cNEPS. Hence, human cNEPs grafted at early times post-stroke support the observed functional recovery following ET-1 stroke but their persistence is not required, thereby supporting a by-stander effect rather than cell replacement.

Neural Stem Cell-Laden Self-Healing Polysaccharide Hydrogel Transplantation Promotes Neurogenesis and Functional Recovery after Cerebral Ischemia in Rats

Exploring a strategy to effectively repair cerebral ischemic injury is a critical requirement for neuroregeneration. Herein, we transplanted a neural stem cell (NSC)-laden self-healing and injectable hydrogel into the brains of ischemic rats and evaluated its therapeutic effects. We observed an improvement in neurological functions in rats transplanted with the NSC-laden hydrogel. This strategy is sufficiently efficient to support neuroregeneration evidenced by NSC proliferation, differentiation, and athletic movement recovery of rats. This therapeutic effect relates to the inhibition of the astrocyte reaction and the increased expression of vascular endothelial growth factor. This work provides a novel approach to repair cerebral ischemic injury.

The Role of BDNF in Experimental and Clinical Traumatic Brain Injury

Traumatic brain injury is one of the leading causes of mortality and morbidity in the world with no current pharmacological treatment. The role of BDNF in neural repair and regeneration is well established and has also been the focus of TBI research. Here, we review experimental animal models assessing BDNF expression following injury as well as clinical studies in humans including the role of BDNF polymorphism in TBI. There is a large heterogeneity in experimental setups and hence the results with different regional and temporal changes in BDNF expression. Several studies have also assessed different interventions to affect the BDNF expression following injury. Clinical studies highlight the importance of BDNF polymorphism in the outcome and indicate a protective role of BDNF polymorphism following injury. Considering the possibility of affecting the BDNF pathway with available substances, we discuss future studies using transgenic mice as well as iPSC in order to understand the underlying mechanism of BDNF polymorphism in TBI and develop a possible pharmacological treatment.

Modulatory properties of extracellular matrix glycosaminoglycans and proteoglycans on neural stem cells behavior: Highlights on regenerative potential and bioactivity

Despite the poor regenerative capacity of the adult central nervous system (CNS) in mammals, two distinct regions, subventricular zone (SVZ) and the subgranular zone (SGZ), continue to generate new functional neurons throughout life which integrate into the pre-existing neuronal circuitry. This process is not fixed but highly modulated, revealing many intrinsic and extrinsic mechanisms by which this performance can be optimized for a given environment. The capacity for self-renewal, proliferation, migration, and multi-lineage potency of neural stem cells (NSCs) underlines the necessity of controlling stem cell fate. In this context, the native and local microenvironment plays a critical role, and the application of this highly organized architecture in the CNS has been considered as a fundamental concept in the generation of new effective therapeutic strategies in tissue engineering approaches. The brain extracellular matrix (ECM) is composed of biomacromolecules, including glycosaminoglycans, proteoglycans, and glycoproteins that provide various biological actions through biophysical and biochemical signaling pathways. Herein, we review predominantly the structure and function of the mentioned ECM composition and their regulatory impact on multiple and diversity of biological functions, including neural regeneration, survival, migration, differentiation, and final destiny of NSCs.

Neglected No More: Emerging Cellular Therapies in Traumatic Injury

Traumatic injuries are a leading cause of death and disability in both military and civilian populations. Given the complexity and diversity of traumatic injuries, novel and individualized treatment strategies are required to optimize outcomes. Cellular therapies have potential benefit for the treatment of acute or chronic injuries, and various cell-based pharmaceuticals are currently being tested in preclinical studies or in clinical trials. Cellular therapeutics may have the ability to complement existing therapies, especially in restoring organ function lost due to tissue disruption, prolonged hypoxia or inflammatory damage. In this article we highlight the current status and discuss future directions of cellular therapies for the treatment of traumatic injury. Both published research and ongoing clinical trials are discussed here.

Traumatic Brain Injury and Stem Cells: An Overview of Clinical Trials, the Current Treatments and Future Therapeutic Approaches

Traumatic brain injury represents physical damage to the brain tissue that induces transitory or permanent neurological disabilities. The traumatic injury activates an important inflammatory response, followed by a cascade of events that lead to neuronal loss and further brain damage. Maintaining proper ventilation, a normal level of oxygenation, and adequate blood pressure are the main therapeutic strategies performed after injury. Surgery is often necessary for patients with more serious injuries. However, to date, there are no therapies that completely resolve the brain damage suffered following the trauma. Stem cells, due to their capacity to differentiate into neuronal cells and through releasing neurotrophic factors, seem to be a valid strategy to use in the treatment of traumatic brain injury. The purpose of this review is to provide an overview of clinical trials, aimed to evaluate the use of stem cell-based therapy in traumatic brain injury. These studies aim to assess the safety and efficacy of stem cells in this disease. The results available so far are few; therefore, future studies need in order to evaluate the safety and efficacy of stem cell transplantation in traumatic brain injury.

Extracellular Vesicles Mediate Neuroprotection and Functional Recovery after Traumatic Brain Injury

The lack of effective therapies for moderate-to-severe traumatic brain injuries (TBIs) leaves patients with lifelong disabilities. Neural stem cells (NSCs) have demonstrated great promise for neural repair and regeneration. However, direct evidence to support their use as a cell replacement therapy for neural injuries is currently lacking. We hypothesized that NSC-derived extracellular vesicles (NSC EVs) mediate repair indirectly after TBI by enhancing neuroprotection and therapeutic efficacy of endogenous NSCs. We evaluated the short-term effects of acute intravenous injections of NSC EVs immediately following a rat TBI. Male NSC EV-treated rats demonstrated significantly reduced lesion sizes, enhanced presence of endogenous NSCs, and attenuated motor function impairments 4 weeks post-TBI, when compared with vehicle- and TBI-only male controls. Although statistically not significant, we observed a therapeutic effect of NSC EVs on brain lesion volume, nestin expression, and behavioral recovery in female subjects. Our study demonstrates the neuroprotective and functional benefits of NSC EVs for treating TBI and points to gender-dependent effects on treatment outcomes, which requires further investigation.

Transplantation of Directly Reprogrammed Human Neural Precursor Cells Following Stroke Promotes Synaptogenesis and Functional Recovery

Stroke is one of the leading causes of long-term disability. Cell transplantation is a promising strategy to treat stroke. We explored the efficacy of directly reprogrammed human neural precursor cell (drNPC) transplants to promote functional recovery in a model of focal ischemic stroke in the mouse sensorimotor cortex. We show that drNPCs express neural precursor cell markers and are neurally committed at the time of transplantation. Mice that received drNPC transplants recovered motor function, irrespective of transplant vehicle or recipient sex, and with no correlation to lesion volume or glial scarring. The majority of drNPCs found in vivo, at the time of functional recovery, remained undifferentiated. Notably, no correlation between functional recovery and long-term xenograft survival was observed, indicating that drNPCs provide therapeutic benefits beyond their survival. Furthermore, increased synaptophysin expression in transplanted brains suggests that drNPCs promote neuroplasticity through enhanced synaptogenesis. Our findings provide insight into the mechanistic underpinnings of drNPC-mediated recovery for stroke and support the notion that drNPCs may have clinical applications for stroke therapy.

Lactobacillus acidophilus Exerts Neuroprotective Effects in Mice with Traumatic Brain Injury

BACKGROUND

Traumatic brain injury (TBI) causes dysbiosis and intestinal barrier disruption, which further exacerbate brain damage via an inflammatory pathway. Gut microbiota remodeling by Lactobacillus acidophilus (LA) is a potential intervention.

OBJECTIVE

The aim of this study was to investigate the neuroprotective effects of LA in TBI and elucidated underlying mechanisms.

METHODS

C57BL/6 male mice (aged 8-9 wk) were subjected to weight-drop impact and gavaged with saline (TBI + vehicle) or LA (1 × 1010 CFU) (TBI + LA) on the day of injury and each day after for 1, 3, or 7 d. The sham + vehicle mice underwent craniotomy without brain injury and were gavaged with saline. Sensorimotor functions were determined pre-TBI and 1, 3, and 7 d postinjury. Indexes of neuroinflammation, peripheral inflammation, and intestinal barrier function were measured on days 3 and 7. Microbiota composition was measured 3 d postinjury. The data were mainly analyzed by 2-factor ANOVA.

RESULTS

Compared with sham + vehicle mice, the TBI + vehicle mice exhibited impairments in the neurological severity score (+692%, day 3; +600%, day 7) and rotarod test (-58%, day 3; -45%, day 7) (P < 0.05), which were rescued by LA. The numbers of microglia (total and activated) and astrocytes and concentrations of TNF-α and IL1-β in the perilesional cortex were elevated in the TBI + vehicle mice on day 3 or 7 compared with sham + vehicle mice (P < 0.05) and were normalized by LA. Compared with sham + vehicle mice, the TBI + vehicle mice exhibited increased serum concentrations of endotoxin and TNF-α, and intestinal barrier permeability (D-lactate) on days 3 and 7 (P < 0.05), and these changes were alleviated by LA. Three days postinjury, the microbiota composition was disrupted in the TBI + vehicle mice compared with sham + vehicle mice (P < 0.05), which was restored by LA.

CONCLUSION

Our results demonstrate that LA exerts neuroprotective effects that may be associated with gut microbiota remodeling in TBI mice.

Neural Stem Cell Transplantation Improves Locomotor Function in Spinal Cord Transection Rats Associated with Nerve Regeneration and IGF-1 R Expression

Transplantation of neural stem cells (NSCs) is a potential strategy for the treatment of spinal cord transection (SCT). Here we investigated whether transplanted NSCs would improve motor function of rats with SCT and explored the underlying mechanism. First, the rats were divided into sham, SCT, and NSC groups. Rats in the SCT and NSC groups were all subjected to SCT in T10, and were administered with media and NSC transplantation into the lesion site, respectively. Immunohistochemistry was used to label Nestin-, TUNEL-, and NeuN-positive cells and reveal the expression and location of type I insulin-like growth factor receptor (IGF-1 R). Locomotor function of hind limbs was assessed by Basso, Beattie, Bresnahan (BBB) score and inclined plane test. The conduction velocity and amplitude of spinal nerve fibers were measured by electrophysiology and the anatomical changes were measured using magnetic resonance imaging. Moreover, expression of IGF-1 R was determined by real-time polymerase chain reaction and Western blotting. The results showed that NSCs could survive and differentiate into neurons in vitro and in vivo. SCT-induced deficits were reduced by NSC transplantation, including increase in NeuN-positive cells and decrease in apoptotic cells. Moreover, neurophysiological profiles indicated that the latent period was decreased and the peak-to-peak amplitude of spinal nerve fibers conduction was increased in transplanted rats, while morphological measures indicated that fractional anisotropy and the number of nerve fibers in the site of spinal cord injury were increased after NSC transplantation. In addition, mRNA and protein level of IGF-1 R were increased in the rostral segment in the NSC group, especially in neurons. Therefore, we concluded that NSC transplantation promotes motor function improvement of SCT, which might be associated with activated IGF-1 R, especially in the rostral site. All of the above suggests that this approach has potential for clinical treatment of spinal cord injury.

Transplantation of human meningioma stem cells loaded on a self-assembling peptide nanoscaffold containing IKVAV improves traumatic brain injury in rats

Traumatic brain injury (TBI) can result in permanent brain function impairment due to the poor regenerative ability of neural tissue. Tissue engineering has appeared as a promising approach to promote nerve regeneration and to ameliorate brain damage. The present study was designed to investigate the effect of transplantation of the human meningioma stem-like cells (hMgSCs) seeded in a promising three-dimensional scaffold (RADA4GGSIKVAV; R-GSIK) on the functional recovery of the brain and neuroinflammatory responses following TBI in rats. After induction of TBI, hMgSCs seeded in R-GSIK was transplanted within the injury site and its effect was compared to several control groups. Application of hMgSCs with R-GSIK improved functional recovery after TBI. A significant higher number of hMgSCs was observed in the brain when transplanted with R-GSIK scaffold compared to the control groups. Application of hMgSCs seeded in R-GSIK significantly decreased the lesion volume, reactive gliosis, and apoptosis at the injury site. Furthermore, treatment with hMgSCs seeded in R-GSIK significantly inhibited the expression of Toll-like receptor 4 and its downstream signaling molecules, including interleukin-1β and tumor necrosis factor. These data revealed the potential for hMgSCs seeded in R-GSIK to improve the functional recovery of the brain after TBI; possibly via amelioration of inflammatory responses. STATEMENT OF SIGNIFICANCE: Tissue engineered scaffolds that mimic the natural extracellular matrix of the brain may modulate stem cell fate and contribute to tissue repair following traumatic brain injury (TBI). Among several scaffolds, self-assembly peptide nanofiber scaffolds markedly promotes cellular behaviors, including cell survival and differentiation. We developed a novel three-dimensional scaffold (RADA16GGSIKVAV; R-GSIK). Transplantation of the human meningioma stem-like cells seeded in R-GSIK in an animal model of TBI significantly improved functional recovery of the brain, possibly via enhancement of stem cell survival as well as reduction of the lesion volume, inflammatory process, and reactive gliosis at the injury site. R-GSIK is a suitable microenvironment for human stem cells and could be a potential biomaterial for the reconstruction of the injured brain after TBI.

Protein Network Analysis of the Serum and Their Functional Implication in Patients Subjected to Traumatic Brain Injury

Traumatic brain injury (TBI) often leads to severe neurobehavioral impairment, but the underlying molecular mechanism remains to be elucidated. Here, we collected the sera from 23 patients (aged from 19 to 81 years old, third day after TBI as TBI-third group) subjected to TBI from The First Hospital of Kunming City, and the sera from 22 healthy donors (aged from 18 to 81 years old and as control group). Then, three samples from TBI-third group and three samples from control group were subjected to the protein microarray detection, and bioinformatics analysis. Then, enzyme-linked immunosorbent assay (ELISA) was used to verify significantly altered protein levels. Results showed that, when compared with the control group, all significantly differentially expressed proteins [DEPs, P < 0.05, FDR < 0.05, fold change (FC) > 2] contained 172 molecules in the TBI-third group, in which 65 proteins were upregulated, while 107 proteins were downregulated. The biological processes of these DEPs, mostly happened in the extracellular region and the extracellular region parts, are mainly involved in the regulation of cellular process, signaling and signal transduction, cell communication, response to stimuli, the immune system process and multicellular organismal development. Moreover, the essential molecular functions of them are cytokine activity, growth factor activity and morphogen activity. Additionally, the most significant pathways are enriched in cytokine–cytokine receptor interaction and PI3K-Akt signaling pathways among downregulated proteins, and pathways in cancer and cytokine–cytokine receptor interaction among upregulated proteins. Of these, we focused on the NGF, NT-3, IGF-2, HGF, NPY, CRP, MMP-9, and ICAM-2 with a high number of interactors in Protein–Protein Interaction (PPI) Network indicated by bioinformatics report. Furthermore, using ELISA test, we confirmed that all increase in the levels of NGF, NT-3, IGF-2, HGF, NPY, CRP, MMP-9, and ICAM-2 in the serum from TBI patients. Together, we determined the screened protein expressional profiles in serum for TBI patients, in which the cross-network between inflammatory factors and growth factors may play a crucial role in TBI damage and repair. Our findings could contribute to indication for the diagnosis and treatment of TBI in future translational medicine and clinical practice.

Do Neural Stem Cells Have a Choice? Heterogenic Outcome of Cell Fate Acquisition in Different Injury Models

The adult mammalian central nervous system (CNS) is generally considered as repair restricted organ with limited capacities to regenerate lost cells and to successfully integrate them into damaged nerve tracts. Despite the presence of endogenous immature cell types that can be activated upon injury or in disease cell replacement generally remains insufficient, undirected, or lost cell types are not properly generated. This limitation also accounts for the myelin repair capacity that still constitutes the default regenerative activity at least in inflammatory demyelinating conditions. Ever since the discovery of endogenous neural stem cells (NSCs) residing within specific niches of the adult brain, as well as the description of procedures to either isolate and propagate or artificially induce NSCs from various origins ex vivo, the field has been rejuvenated. Various sources of NSCs have been investigated and applied in current neuropathological paradigms aiming at the replacement of lost cells and the restoration of functionality based on successful integration. Whereas directing and supporting stem cells residing in brain niches constitutes one possible approach many investigations addressed their potential upon transplantation. Given the heterogeneity of these studies related to the nature of grafted cells, the local CNS environment, and applied implantation procedures we here set out to review and compare their applied protocols in order to evaluate rate-limiting parameters. Based on our compilation, we conclude that in healthy CNS tissue region specific cues dominate cell fate decisions. However, although increasing evidence points to the capacity of transplanted NSCs to reflect the regenerative need of an injury environment, a still heterogenic picture emerges when analyzing transplantation outcomes in injury or disease models. These are likely due to methodological differences despite preserved injury environments. Based on this meta-analysis, we suggest future NSC transplantation experiments to be conducted in a more comparable way to previous studies and that subsequent analyses must emphasize regional heterogeneity such as accounting for differences in gray versus white matter.

BDNF, Brain, and Regeneration: Insights from Zebrafish

Zebrafish (Danio rerio) is a teleost fish widely accepted as a model organism for neuroscientific studies. The adults show common basic vertebrate brain structures, together with similar key neuroanatomical and neurochemical pathways of relevance to human diseases. However, the brain of adult zebrafish possesses, differently from mammals, intense neurogenic activity, which can be correlated with high regenerative properties. Brain derived neurotrophic factor (BDNF), a member of the neurotrophin family, has multiple roles in the brain, due also to the existence of several biologically active isoforms, that interact with different types of receptors. BDNF is well conserved in the vertebrate evolution, with the primary amino acid sequences of zebrafish and human BDNF being 91% identical. Here, we review the available literature regarding BDNF in the vertebrate brain and the potential involvement of BDNF in telencephalic regeneration after injury, with particular emphasis to the zebrafish. Finally, we highlight the potential of the zebrafish brain as a valuable model to add new insights on future BDNF studies.

Combined acupuncture and HuangDiSan treatment affects behavior and synaptophysin levels in the hippocampus of senescence-accelerated mouse prone 8 after neural stem cell transplantation

Sanjiao acupuncture and HuangDiSan can promote the proliferation, migration and differentiation of exogenous neural stem cells in senescence-accelerated mouse prone 8 (SAMP8) mice and can improve learning and memory impairment and behavioral function in dementia-model mice. Thus, we sought to determine whether Sanjiao acupuncture and HuangDiSan can elevate the effect of neural stem cell transplantation in Alzheimer’s disease model mice. Sanjiao acupuncture was used to stimulate Danzhong (CV17), Zhongwan (CV12), Qihai (CV6), bilateral Xuehai (SP10) and bilateral Zusanli (ST36) 15 days before and after implantation of neural stem cells (5 × 10⁵) into the hippocampal dentate gyrus of SAMP8 mice. Simultaneously, 0.2 mL HuangDiSan, containing Rehmannia Root and Chinese Angelica, was intragastrically administered. Our results demonstrated that compared with mice undergoing neural stem cell transplantation alone, learning ability was significantly improved and synaptophysin mRNA and protein levels were greatly increased in the hippocampus of mice undergoing both Sanjiao acupuncture and intragastric administration of HuangDiSan. We conclude that the combination of Sanjiao acupuncture and HuangDiSan can effectively improve dementia symptoms in mice, and the mechanism of this action might be related to the regulation of synaptophysin expression.

Mini Review of Controlled Cortical Impact: A Well-Suited Device for Concussion Research

Mild traumatic brain injury (mTBI) is increasingly recognized as a significant public health problem which warrants additional research. Part of the effort to understand mTBI and concussion includes modeling in animals. Controlled cortical impact (CCI) is a commonly employed and well-characterized model of experimental TBI that has been utilized for three decades. Today, several commercially available pneumatic- and electromagnetic-CCI devices exist as do a variety of standard and custom injury induction tips. One of CCI's strengths is that it can be scaled to a number of common laboratory animals. Similarly, the CCI model can be used to produce graded TBI ranging from mild to severe. At the mild end of the injury spectrum, CCI has been applied in many ways, including to study open and closed head mTBI, repeated injuries, and the long-term deficits associated with mTBI and concussion. The purpose of this mini-review is to introduce the CCI model, discuss ways the model can be applied to study mTBI and concussion, and compare CCI to alternative pre-clinical TBI models.