Advanced Progress in the Role of Adipose-Derived Mesenchymal Stromal/Stem Cells in the Application of Central Nervous System Disorders

Currently, adipose-derived mesenchymal stromal/stem cells (ADMSCs) are recognized as a highly promising material for stem cell therapy due to their accessibility and safety. Given the frequently irreversible damage to neural cells associated with CNS disorders, ADMSC-related therapy, which primarily encompasses ADMSC transplantation and injection with exosomes derived from ADMSCs or secretome, has the capability to inhibit inflammatory response and neuronal apoptosis, promote neural regeneration, as well as modulate immune responses, holding potential as a comprehensive approach to treat CNS disorders and improve prognosis. Empirical evidence from both experiments and clinical trials convincingly demonstrates the satisfactory safety and efficacy of ADMSC-related therapies. This review provides a systematic summary of the role of ADMSCs in the treatment of central nervous system (CNS) disorders and explores their therapeutic potential for clinical application. ADMSC-related therapy offers a promising avenue to mitigate damage and enhance neurological function in central nervous system (CNS) disorders. However, further research is necessary to establish the safety and efficacy of clinical ADMSC-based therapy, optimize targeting accuracy, and refine delivery approaches for practical applications.

Improving Efficiency of Direct Pro-Neural Reprogramming: Much-Needed Aid for Neuroregeneration in Spinal Cord Injury

Spinal cord injury (SCI) is a medical condition affecting ~2.5-4 million people worldwide. The conventional therapy for SCI fails to restore the lost spinal cord functions; thus, novel therapies are needed. Recent breakthroughs in stem cell biology and cell reprogramming revolutionized the field. Of them, the use of neural progenitor cells (NPCs) directly reprogrammed from non-neuronal somatic cells without transitioning through a pluripotent state is a particularly attractive strategy. This allows to "scale up" NPCs in vitro and, via their transplantation to the lesion area, partially compensate for the limited regenerative plasticity of the adult spinal cord in humans. As recently demonstrated in non-human primates, implanted NPCs contribute to the functional improvement of the spinal cord after injury, and works in other animal models of SCI also confirm their therapeutic value. However, direct reprogramming still remains a challenge in many aspects; one of them is low efficiency, which prevents it from finding its place in clinics yet. In this review, we describe new insights that recent works brought to the field, such as novel targets (mitochondria, nucleoli, G-quadruplexes, and others), tools, and approaches (mechanotransduction and electrical stimulation) for direct pro-neural reprogramming, including potential ones yet to be tested.

New insights into the biological roles of immune cells in neural stem cells in post-traumatic injury of the central nervous system

Traumatic injuries in the central nervous system, such as traumatic brain injury and spinal cord injury, are associated with tissue inflammation and the infiltration of immune cells, which simultaneously affect the self-renewal and differentiation of neural stem cells. However, the tissue repair process instigated by endogenous neural stem cells is incapable of restoring central nervous system injuries without external intervention. Recently, resident/peripheral immune cells have been demonstrated to exert significant effects on neural stem cells. Thus, the restoration of traumatic injuries in the central nervous system by the immune intervention in neural stem cells represents a potential therapeutic method. In this review, we discuss the roles and possible mechanisms of immune cells on the self-renewal and differentiation of neural stem cells along with the prognosis of central nervous system injuries based on immune intervention. Finally, we discuss remaining research challenges that need to be considered in the future. Further elucidation of these challenges will facilitate the successful application of neural stem cells in central nervous system injuries.

Extracellular traps formation following cervical spinal cord injury

Spinal cord injuries involve a primary injury that can lead to permanent loss of function and a secondary injury associated with pathologic and inflammatory processes. Extracellular traps are extracellular structures expressed by immune cells that are primarily composed of chromatin, granular enzymes and histones. Extracellular traps are known to induce tissue damage when overexpressed and could be associated in the occurrence of secondary damage. In the present study, we used flow cytometry to demonstrate that at 1 day following a C2 spinal cord lateral hemisection in male Swiss mice, resident microglia form vital microglia extracellular traps, and infiltrating neutrophils form vital neutrophil extracellular traps. We also used immunolabelling to show that microglia near the lesion area are most likely to form these microglia extracellular traps. As expected, infiltrating neutrophils are located at the site of injury, though only some of them engage in post-injury extracellular trap formation. We also observed the formation of microglia and neutrophil extracellular traps in our sham animal models of durotomy, but formation was less frequent than following the C2 hemisection. Our results demonstrate for the first time that microglia form extracellular traps in the spinal cord following injury and durotomy. It remains however to determine the exact mechanisms and kinetics of neutrophil and microglia extracellular traps formation following spinal cord injury. This information would allow to better mitigate this inflammatory process that may contribute to secondary injury and to effectively target extracellular traps to improve functional outcomes following spinal cord injury.

Bridging the gap of axonal regeneration in the central nervous system: A state of the art review on central axonal regeneration

Neuronal regeneration in the central nervous system (CNS) is an important field of research with relevance to all types of neuronal injuries, including neurodegenerative diseases. The glial scar is a result of the astrocyte response to CNS injury. It is made up of many components creating a complex environment in which astrocytes play various key roles. The glial scar is heterogeneous, diverse and its composition depends upon the injury type and location. The heterogeneity of the glial scar observed in different situations of CNS damage and the consequent implications for axon regeneration have not been reviewed in depth. The gap in this knowledge will be addressed in this review which will also focus on our current understanding of central axonal regeneration and the molecular mechanisms involved. The multifactorial context of CNS regeneration is discussed, and we review newly identified roles for components previously thought to solely play an inhibitory role in central regeneration: astrocytes and p75NTR and discuss their potential and relevance for deciding therapeutic interventions. The article ends with a comprehensive review of promising new therapeutic targets identified for axonal regeneration in CNS and a discussion of novel ways of looking at therapeutic interventions for several brain diseases and injuries.

The lymphatic system: a therapeutic target for central nervous system disorders

The lymphatic vasculature forms an organized network that covers the whole body and is involved in fluid homeostasis, metabolite clearance, and immune surveillance. The recent identification of functional lymphatic vessels in the meninges of the brain and the spinal cord has provided novel insights into neurophysiology. They emerge as major pathways for fluid exchange. The abundance of immune cells in lymphatic vessels and meninges also suggests that lymphatic vessels are actively involved in neuroimmunity. The lymphatic system, through its role in the clearance of neurotoxic proteins, autoimmune cell infiltration, and the transmission of pro-inflammatory signals, participates in the pathogenesis of a variety of neurological disorders, including neurodegenerative and neuroinflammatory diseases and traumatic injury. Vascular endothelial growth factor C is the master regulator of lymphangiogenesis, a process that is critical for the maintenance of central nervous system homeostasis. In this review, we summarize current knowledge and recent advances relating to the anatomical features and immunological functions of the lymphatic system of the central nervous system and highlight its potential as a therapeutic target for neurological disorders and central nervous system repair.

Liver transplantation in rare late-onset ornithine transcarbamylase deficiency with central nervous system injury: A case report and review of the literature

BACKGROUND

Ornithine transcarbamylase deficiency (OTCD) is a genetic metabolic disease. Its clinical manifestations are mainly central nervous system dysfunction caused by high blood ammonia. Late-onset OTCD combined with central nervous system injury has a poor therapeutic response, which is one of the main factors affecting the prognosis and quality of life of patients. liver transplantation (LT) has gradually become a radical treatment for OTCD, which has achieved good results. However, there is no consensus on the timing of LT and problems of nervous system damage and repair.

METHODS

We report the development of late-onset OTCD with central nervous system injury in an 11-year-old child who received liver transplantation at our transplant center. His first symptoms were nonprojectile vomiting, followed by irritability and disturbance of consciousness, after which the disease progressed rapidly and finally resulted in a coma. After liver transplantation, the child's consciousness returned to normal, muscle strength of the limbs gradually recovered from grade 0 to grade 4, and muscle tone gradually recovered from grade 4 to grade 1, suggesting that the motor nerves had gradually recovered. However, the child is currently mentally retarded, and the language center has not yet fully recovered.At the same time, we made a literature review of OTCD.

CONCLUSION

For OTCD patients with central nervous system injury, liver transplantation can fundamentally solve the problem of ammonia metabolism in the liver and avoids further damage to the central nervous system caused by hyperammonemia. At the same time, children's nervous systems are in the developmental stage when neuroplasticity is greatest. If liver transplantation is performed as soon as possible, nerve repair is still possible.

Immuno-affinity Potent Strip with Pre-Embedded Intermixed PEDOT:PSS Conductive Polymers and Graphene Nanosheets for Bio-Ready Electrochemical Biosensing of Central Nervous System Injury Biomarkers

Future point-of-care (PoC) and wearable electrochemical biosensors explore new technology solutions to eliminate the need for multistep electrode modification and functionalization, overcome the limited reproducibility, and automate the sensing steps. In this work, a new screen-printed immuno-biosensor strip is engineered and characterized using a hybrid graphene nanosheet intermixed with the conductive poly(3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS) polymers, all embedded within the base carbon matrix (GiPEC) of the screen-printing ink. This intermixed nanocomposite ink is chemically designed for self-containing the "carboxyl" functional groups as the most specific chemical moiety for protein immobilization on the electrodes. The GiPEC ink enables capturing the target antibodies on the electrode without any need for extra surface preparation. As a proof of concept, the performance of the non-functionalized ready-to-immobilize strips was assessed for the detection of glial fibrillary acidic protein (GFAP) as a known central nervous system injury blood biomarker. This immuno-biosensor exhibits the limit of detection of 281.7 fg mL^-1 (3 signal-to-noise ratio) and the sensitivity of 322.6 Ω mL pg^-1 mm^-2 within the clinically relevant linear detection range from 1 pg mL^-1 to 10 ng mL^-1. To showcase its potential PoC application, the bio-ready strip is embedded inside a capillary microfluidic device and automates electrochemical quantification of GFAP spiked in phosphate-buffered saline and the human serum. This new electrochemical biosensing platform can be further adapted for the detection of various protein biomarkers with the application in realizing on-chip immunoassays.

Investigating Mechanisms of Subcutaneous Preconditioning Incubation for Neural Stem Cell Embedded Hydrogels

Stem cells are a vital component of regenerative medicine therapies, however, only a fraction of stem cells delivered to the central nervous system following injury survive the inflammatory environment. Previously, we showed that subcutaneous preconditioning of neural stem cell (NSC) embedded hydrogels for 28 days improved spinal cord injury (SCI) functional outcomes over controls. Here, we investigated the mechanism of subcutaneous preconditioning of NSC-embedded hydrogels, with and without the known neurogenic cue, interferon gamma (IFN-γ), for 3, 14, or 28 days to refine and identify subcutaneous preconditioning conditions by measurement of neurogenic markers and cytokines. Studying the preconditioning mechanism, we found that subcutaneous foreign body response (FBR) associated cytokines infiltrated the scaffold in groups with and without NSCs, with time point effects. A pro-inflammatory environment with upregulated interleukin (IL)-6, IL-10, macrophage inflammatory protein (MIP)-1, MIP-2, IFN-γ-inducible protein 10 (IP-10), tumor necrosis factor-α (TNF-α), and IL-12p70 was observed on day 3. By 14 and 28 days, there was an increase in pro-regenerative cytokines (IL-13, IL-4) along with pro-inflammatory markers IL-1β, IP-10, and RANTES (regulated on activation, normal T cell expressed, and secreted) potentially part of the mechanism that had an increased functional outcome in SCI. Coinciding with changes in cytokines, the macrophage population increased over time from 3 to 28 days, whereas neutrophils peaked at 3 days with a significant decrease at later time points. Expression of the neuronal marker βIII tubulin in differentiating NSCs was supported at 3 days in the presence of soluble and immobilized IFN-γ and at 14 days by immobilized IFN-γ only, but it was greatly attenuated in all conditions at 28 days, partially because of dilution via host cell infiltration. We conclude that subcutaneously incubating NSC seeded scaffolds for 3 or 14 days could act as host specific preconditioning through exposure to FBR while retaining βIII tubulin expression of NSCs to further improve the SCI functional outcome observed with 28 day subcutaneous incubation.

Pharmacological Modulation and (Patho)Physiological Roles of TRPM4 Channel-Part 2: TRPM4 in Health and Disease

Transient receptor potential melastatin 4 (TRPM4) is a unique member of the TRPM protein family and, similarly to TRPM5, is Ca²⁺ sensitive and permeable for monovalent but not divalent cations. It is widely expressed in many organs and is involved in several functions; it regulates membrane potential and Ca²⁺ homeostasis in both excitable and non-excitable cells. This part of the review discusses the currently available knowledge about the physiological and pathophysiological roles of TRPM4 in various tissues. These include the physiological functions of TRPM4 in the cells of the Langerhans islets of the pancreas, in various immune functions, in the regulation of vascular tone, in respiratory and other neuronal activities, in chemosensation, and in renal and cardiac physiology. TRPM4 contributes to pathological conditions such as overactive bladder, endothelial dysfunction, various types of malignant diseases and central nervous system conditions including stroke and injuries as well as in cardiac conditions such as arrhythmias, hypertrophy, and ischemia-reperfusion injuries. TRPM4 claims more and more attention and is likely to be the topic of research in the future.

Hepatocyte Growth Factor-Preconditioned Neural Progenitor Cells Attenuate Astrocyte Reactivity and Promote Neurite Outgrowth

The astroglial scar is a defining hallmark of secondary pathology following central nervous system (CNS) injury that, despite its role in limiting tissue damage, presents a significant barrier to neuroregeneration. Neural progenitor cell (NPC) therapies for tissue repair and regeneration have demonstrated favorable outcomes, the effects of which are ascribed not only to direct cell replacement but trophic support. Cytokines and growth factors secreted by NPCs aid in modifying the inhibitory and cytotoxic post-injury microenvironment. In an effort to harness and enhance the reparative potential of NPC secretome, we utilized the multifunctional and pro-regenerative cytokine, hepatocyte growth factor (HGF), as a cellular preconditioning agent. We first demonstrated the capacity of HGF to promote NPC survival in the presence of oxidative stress. We then assessed the capacity of this modified conditioned media (CM) to attenuate astrocyte reactivity and promote neurite outgrowth in vitro. HGF pre-conditioned NPCs demonstrated significantly increased levels of tissue inhibitor of metalloproteinases-1 and reduced vascular endothelial growth factor compared to untreated NPCs. In reactive astrocytes, HGF-enhanced NPC-CM effectively reduced glial fibrillary acidic protein (GFAP) expression and chondroitin sulfate proteoglycan deposition to a greater extent than either treatment alone, and enhanced neurite outgrowth of co-cultured neurons. in vivo, this combinatorial treatment strategy might enable tactical modification of the post-injury inhibitory astroglial environment to one that is more conducive to regeneration and functional recovery. These findings have important translational implications for the optimization of current cell-based therapies for CNS injury.

Central Nervous System Injury in Patients With Severe Acute Respiratory Syndrome Coronavirus 2: MRI Findings

Due to the presence of a new and rapidly spreading coronavirus, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the World Health Organization declared the coronavirus disease 2019 (COVID-19) outbreak a pandemic on March 11, 2020. This new disease has a multisystemic effect that predominantly targets the respiratory system; however, neurologic symptoms have been documented in approximately 36% of patients with confirmed COVID-19. During the period of March 2020 to March 2021, 481 brain MRI studies were performed by medical request. Of these, 9.7% (n = 47) were hospitalized with a diagnosis of COVID-19 pneumonia confirmed by SARS-CoV-2 reverse transcriptase-polymerase chain reaction (RT-PCR) test with the following findings: microbleeds, osmotic demyelination, arterial thrombosis, ischemic infarcts, venous thrombosis, metabolic cerebellar syndrome, posterior reversible leukoencephalopathy, abnormal signal intensity in the frontal lobes and olfactory bulbs, microangiopathy, gliosis, and findings consistent with hypoxic-ischemic encephalopathy. In patients with histories of malignant central nervous system (CNS) tumors, the most frequent histological lineage being high-grade glioma, 100% progression was identified with respect to previous imaging studies, without other significant findings. In two patients, a brain MRI was performed due to altered alertness, identifying only involutive changes in the brain parenchyma; MRI was repeated 72 hours later, after a lack of improvement in higher functions, without identifying imaging findings. To date, limited studies have documented CNS abnormalities related to COVID-19 using MRI. Therefore, the purpose of this study is to present abnormal imaging findings in patients with SARS-CoV-2 infection and their clinical correlations.

CTRP6(C1q/Tumor Necrosis Factor (TNF)-related protein-6) alleviated the sevoflurane induced injury of mice central nervous system by promoting the expression of p-Akt (phosphorylated Akt)

Postoperative cognitive impairment and nervous system damage caused by anesthetics seriously affect patient’s postoperative recovery. Recent study has revealed that CTRP6 could alleviate apoptosis, inflammation and oxidative stress of nerve cells, thereby relieving nervous system damage induced by cerebral ischemia reperfusion. However, whether CTRP6 could relieve sevoflurane induced central nervous system injury is unclear. We stimulated C57BL/6 mice with sevoflurane and injected CTRP6 overexpression adenovirus vector. Next, H&E staining and TUNEL assays were performed to examine the effect of CTRP6 on sevoflurane induced injury of central nervous system. Finally, we isolated primary nerve cells of hippocampus. Flow cytometry and commercial kits were used for the detection of apoptosis and ROS levels of these cells. Western blotting was used for the detection of the expression level of p-Akt in central nervous tissues and primary cells. Results showed that sevoflurane induced injury and apoptosis of central nervous tissues. Overexpression of CTRP6 relieved apoptosis and injury of these tissues. CTRP6 inhibited the expression of cleaved caspase-3 and cleaved PARP in these tissues. Sevoflurane promoted apoptosis of primary cells and enhanced the expression of ROS and MDA in these cells. Overexpression of CTRP6 alleviated apoptosis and suppressed production of ROS and MDA in these cells. In addition, CTRP6 also enhanced the expression of p-Akt in primary cells. Taken together, our results suggested that CTRP6 relieved sevoflurane induced injury of central nervous tissues by promoting the expression of p-Akt. Therefore, the targeted drug of CTRP6 should be explored for the remission of these symptoms.

Neurotrophic factor levels in the serum and cerebrospinal fluid of neonates infected with human cytomegalovirus

Human cytomegalovirus (HCMV) is most likely to damage the central nervous system (CNS) during early embryonic development; however, the early neurodevelopmental abnormalities caused by HCMV infection and the regulation of cytokines remain unclear. Therefore, we investigated neuronal factors in the serum and cerebrospinal fluid (CSF) of newborns infected with HCMV using protein microarray technology with a view to elucidating the changes in specific neuronal factors for use in the development of a reliable index for predicting CNS injury caused by HCMV infection. Serum and CSF were collected from four newborns with HCMV infection and CNS injury (HCMV-infected group) and from four newborns without CNS infection (control group). A protein microarray containing 29 kinds of CNS-related cytokines was used to identify differentially expressed neuronal factors in the serum and CSF of the HCMV-infected and control groups. The levels of the differentially expressed proteins were verified further in 30 CSF samples from an HCMV-infected group using enzyme-linkedimmunosorbent assay (ELISA). Between newborns in the HCMV-infected and control groups, the protein microarray analysis identified three differentially expressed neurotrophic factors in the CSF samples: Acrp30, MMP-3, and interleukin-1 alpha (IL-1α). No differential cytokine expression was seen in the serum. ELISA showed significantly higher expression levels of Acrp30 and MMP-3 in the CSF of the 30 newborns with HCMV infection and CNS injury than in those in the control group, whereas the expression of IL-1α was significantly lower. Our results demonstrate that changes in the expression levels of Acrp30, MMP-3, and IL-1α in the CSF of newborns infected with HCMV may be related to the pathogenesis of CNS infection.

Chondroitinase ABC/galectin-3 fusion proteins with hyaluronan-based hydrogels stabilize enzyme and provide targeted enzyme activity for neural applications

Objective. Chondroitinase ABC (ChABC) has emerged as a promising therapeutic agent for central nervous system regeneration. Despite multiple beneficial outcomes for regeneration, translation of this enzyme is challenged by poor pharmacokinetics, localization, and stability.Approach. This study explored the function andin vitroapplication of engineered ChABC fused to galectin-3 (Gal3). Two previously developed ChABC-Gal3 oligomers (monomeric and trimeric) were evaluated for functionality and kinetics, then applied to anin vitrocellular outgrowth model using dorsal root ganglia (DRGs). The fusions were combined with two formulations of hyaluronan (HA)-based scaffolds to determine the extent of active enzyme release compared to wild type (WT) ChABC.Main Results. Monomeric and trimeric ChABC-Gal3 maintained digestive capabilities with kinetic properties that were substrate-dependent for chondroitin sulfates A, B, and C. The fusions had longer half-lives at 37 °C on the order of seven fold for monomer and twelve fold for trimer compared to WT. Both fusions were also effective at restoring DRG outgrowthin vitro. To create a combination approach, two triple-component hydrogels containing modified HA were formulated to match the mechanical properties of native spinal cord tissue and to support astrocyte viability (>80%) and adhesion. The hydrogels included collagen-I and laminin mixed with either 5 mg ml^-1of glycidyl methacrylate HA or 3 mg ml^-1Hystem. When combined with scaffolds, ChABC-Gal3 release time was lengthened compared to WT. Both fusions had measurable enzymatic activity for at least 10 d when incorporated in gels, compared to WT that lost activity after 1 d. These longer term release products from gels maintained adequate function to promote DRG outgrowth.Significance. Results of this study demonstrated cohesive benefits of two stabilized ChABC-Gal3 oligomers in combination with HA-based scaffolds for neural applications. Significant improvements to ChABC stability and release were achieved, meriting future studies of ChABC-Gal3/hydrogel combinations to target neural regeneration.

Bidirectional Brain-gut-microbiota Axis in increased intestinal permeability induced by central nervous system injury

Central nervous system injuries may lead to the disorders of the hypothalamic‐pituitary‐adrenal axis, autonomic nervous system, and enteric nervous system. These effects then cause the changes in the intestinal microenvironment, such as a disordered intestinal immune system as well as alterations of intestinal bacteria. Ultimately, this leads to an increase in intestinal permeability. Inflammatory factors produced by the interactions between intestinal neurons and immune cells as well as the secretions and metabolites of intestinal flora can then migrate through the intestinal barrier, which will aggravate any peripheral inflammation and the central nervous system injury. The brain‐gut‐microbiota axis is a complex system that plays a crucial role in the occurrence and development of central nervous system diseases. It may also increase the consequences of preventative treatment. In this context, here we have summarized the factors that can lead to the increased intestinal permeability and some of the possible outcomes.

Biomarkers in Spinal Cord Injury: Prognostic Insights and Future Potentials

Spinal Cord Injury (SCI) is a major challenge in Neurotrauma research. Complex pathophysiological processes take place immediately after the injury and later on as the chronic injury develops. Moreover, SCI is usually accompanied by traumatic injuries because the most common modality of injury is road traffic accidents and falls. Patients develop significant permanent neurological deficits that depend on the extent and the location of the injury itself and in time they develop further neurological and body changes that may risk their mere survival. In our review, we explored the recent updates with regards to SCI biomarkers. We observed two methods that may lead to the appearance of biomarkers for SCI. First, during the first few weeks following the injury the Blood Spinal Cord Barrier (BSCB) disruption that releases several neurologic structure components from the injured tissue. These components find their way to Cerebrospinal Fluid (CSF) and the systemic circulation. Also, as the injury develops several components of the pathological process are expressed or released such as in neuroinflammation, apoptosis, reactive oxygen species, and excitotoxicity sequences. Therefore, there is a growing interest in examining any correlations between these components and the degrees or the outcomes of the injury. Additionally, some of the candidate biomarkers are theorized to track the progressive changes of SCI which offers an insight on the patients' prognoses, potential-treatments-outcomes assessment, and monitoring the progression of the complications of chronic SCI such as Pressure Ulcers and urinary dysfunction. An extensive literature review was performed covering literature, published in English, until February 2018 using the Medline/PubMed database. Experimental and human studies were included and titles, PMID, publication year, authors, biomarkers studies, the method of validation, relationship to SCI pathophysiology, and concluded correlation were reported. Potential SCI biomarkers need further validation using clinical studies. The selection of the appropriate biomarker group should be made based on the stage of the injuries, the accompanying trauma and with regards to any surgical, or medical interference that might have been done. Additionally, we suggest testing multiple biomarkers related to the several pathological changes coinciding to offer a more precise prediction of the outcome.

Modulation of the Endocannabinoid System Following Central Nervous System Injury

Central nervous system (CNS) injury, such as stroke or trauma, is known to increase susceptibility to various infections that adversely affect patient outcomes (CNS injury-induced immunodepression-CIDS). The endocannabinoid system (ECS) has been shown to have immunoregulatory properties. Therefore, the ECS might represent a druggable target to overcome CIDS. Evidence suggests that cannabinoid type 2 receptor (CB₂R) activation can be protective during the early pro-inflammatory phase after CNS injury, as it limits neuro-inflammation and, therefore, attenuates CIDS severity. In the later phase post CNS injury, CB₂R inhibition is suggested as a promising pharmacologic strategy to restore immune function in order to prevent infection.

Polyethylenimine Modified Graphene-Oxide Electrochemical Immunosensor for the Detection of Glial Fibrillary Acidic Protein in Central Nervous System Injury

Glial fibrillary acidic protein (GFAP) is as an intermediate filament protein expressed by certain cells in the central nervous system (CNS). GFAP has been recognized as a reliable biomarker of CNS injury. However, due to the absence of rapid and easy-to-use assays for the detection of CNS injury biomarkers, measuring GFAP levels to identify CNS injury has not attained widespread clinical implementation. In the present work, we developed a polyethylenimine (PEI) coated graphene screen-printed electrode and used it for highly sensitive immunosensing of GFAP. Covalent binding of GFAP antibody to the PEI-modified electrode surface along with electrochemical impedance spectroscopy was used for detecting the change in the electrical conductivity of the electrodes. A highly linear response was recorded for various GFAP concentrations. Quantitative, selective, and label-free detection was achieved in the dynamic range of 1 pg mL^-1 to 100 ng mL^-1 for GFAP spiked in phosphate buffer saline, artificial cerebrospinal fluid, and human blood serum. The performance of the immunosensor was further validated and correlated by testing samples with the commercially available enzyme-linked immunosorbent assay method. This functionalized electrode could be used clinically for rapid detection and monitoring of CNS injury.

Intramuscular Neurotrophin-3 normalizes low threshold spinal reflexes, reduces spasms and improves mobility after bilateral corticospinal tract injury in rats

Brain and spinal injury reduce mobility and often impair sensorimotor processing in the spinal cord leading to spasticity. Here, we establish that complete transection of corticospinal pathways in the pyramids impairs locomotion and leads to increased spasms and excessive mono- and polysynaptic low threshold spinal reflexes in rats. Treatment of affected forelimb muscles with an adeno-associated viral vector (AAV) encoding human Neurotrophin-3 at a clinically-feasible time-point after injury reduced spasticity. Neurotrophin-3 normalized the short latency Hoffmann reflex to a treated hand muscle as well as low threshold polysynaptic spinal reflexes involving afferents from other treated muscles. Neurotrophin-3 also enhanced locomotor recovery. Furthermore, the balance of inhibitory and excitatory boutons in the spinal cord and the level of an ion co-transporter in motor neuron membranes required for normal reflexes were normalized. Our findings pave the way for Neurotrophin-3 as a therapy that treats the underlying causes of spasticity and not only its symptoms.

DOI:http://dx.doi.org/10.7554/eLife.18146.001

Injuries to the brain and spinal cord cause disability in millions of people worldwide. Physical rehabilitation can restore some muscle control and improve mobility in affected individuals. However, no current treatments provide long-term relief from the unwanted muscle contractions and spasms that affect as many as 78% of people with a spinal cord injury. These spasms can seriously hamper a person’s ability to carry out day-to-day tasks and get around independently. A few treatments can help in the short term but have side effects; indeed while Botox injections are used to paralyse the muscle, these also reduce the chances of useful improvements. As such, better therapies for muscle spasms are needed; especially ones that reduce spasms in the arms.

Rats with injuries to the spinal cord between their middle to lower back typically develop spasms in their legs or tail, and rat models have helped scientists begin to understand why these involuntary movements occur. Now, Kathe et al. report that cutting one specific pathway that connects the brain to the spinal cord in anesthetised rats leads to the development of spasms in the forelimbs as well. Several months after the surgery, the rats had spontaneous muscle contractions in their forelimbs and walked abnormally. Further experiments showed that some other neural pathways in the rats became incorrectly wired and hyperactive and that this resulted in the abnormal movements.

Next, Kathe et al. asked whether using gene therapy to deliver a protein that is required for neural circuits to form between muscles and the spinal cord (called neurotrophin-3) would stop the involuntary movements in the forelimbs. Delivering the gene therapy directly into the forelimb muscles of the disabled rats a day after their injury increased the levels of neurotrophin-3 in these muscles. Rats that received this treatment had fewer spasms and walked better than those that did not. Further experiments confirmed that this was because the rats’ previously hyperactive and abnormally wired neural circuits became more normal after the treatment.

Together these results suggest that neurotrophin-3 might be a useful treatment for muscle spasms in people with spinal injury. There have already been preliminary studies in people showing that treatment with neurotrophin-3 is safe and well tolerated. Future studies are needed to confirm that it could be useful in humans.

DOI:http://dx.doi.org/10.7554/eLife.18146.002

CB2 and GPR55 Receptors as Therapeutic Targets for Systemic Immune Dysregulation

The endocannabinoid system (ECS) is involved in many physiological processes and has been suggested to play a critical role in the immune response and the central nervous system (CNS). Therefore, ECS modulation has potential therapeutic effects on immune dysfunctional disorders, such as sepsis and CNS injury-induced immunodeficiency syndrome (CIDS). In sepsis, excessive release of pro- and anti-inflammatory mediators results in multi-organ dysfunction, failure, and death. In CIDS, an acute CNS injury dysregulates a normally well-balanced interplay between CNS and the immune system, leading to increased patients’ susceptibility to infections. In this review, we will discuss potential therapeutic modulation of the immune response in sepsis and CNS injury by manipulation of the ECS representing a novel target for immunotherapy.

Regeneration strategies after the adult mammalian central nervous system injury-biomaterials

The central nervous system (CNS) has very restricted intrinsic regeneration ability under the injury or disease condition. Innovative repair strategies, therefore, are urgently needed to facilitate tissue regeneration and functional recovery. The published tissue repair/regeneration strategies, such as cell and/or drug delivery, has been demonstrated to have some therapeutic effects on experimental animal models, but can hardly find clinical applications due to such methods as the extremely low survival rate of transplanted cells, difficulty in integrating with the host or restriction of blood–brain barriers to administration patterns. Using biomaterials can not only increase the survival rate of grafts and their integration with the host in the injured CNS area, but also sustainably deliver bioproducts to the local injured area, thus improving the microenvironment in that area. This review mainly introduces the advances of various strategies concerning facilitating CNS regeneration.

Human amniotic epithelial cells express specific markers of nerve cells and migrate along the nerve fibers in the corpus callosum

Human amniotic epithelial cells were isolated from a piece of fresh amnion. Using immunocytochemical methods, we investigated the expression of neuronal phenotypes (microtubule-associated protein-2, glial fibrillary acidic protein and nestin) in human amniotic epithelial cells. The conditioned medium of human amniotic epithelial cells promoted the growth and proliferation of rat glial cells cultured in vitro, and this effect was dose-dependent. Human amniotic epithelial cells were further transplanted into the corpus striatum of healthy adult rats and the grafted cells could integrate with the host and migrate 1–2 mm along the nerve fibers in corpus callosum. Our experimental findings indicate that human amniotic epithelial cells may be a new kind of seed cells for use in neurograft.

Mild hypothermia as a treatment for central nervous system injuries: Positive or negative effects

Besides local neuronal damage caused by the primary insult, central nervous system injuries may secondarily cause a progressive cascade of related events including brain edema, ischemia, oxida-tive stress, excitotoxicity, and dysregulation of calcium homeostasis. Hypothermia is a beneficial strategy in a variety of acute central nervous system injuries. Mild hypothermia can treat high intra-cranial pressure following traumatic brain injuries in adults. It is a new treatment that increases sur-vival and quality of life for patients suffering from ischemic insults such as cardiac arrest, stroke, and neurogenic fever following brain trauma. Therapeutic hypothermia decreases free radical produc-tion, inflammation, excitotoxicity and intracranial pressure, and improves cerebral metabolism after traumatic brain injury and cerebral ischemia, thus protecting against central nervous system dam-age. Although a series of pathological and physiological changes as well as potential side effects are observed during hypothermia treatment, it remains a potential therapeutic strategy for central nervous system injuries and deserves further study.

Leukemia inhibitor factor promotes functional recovery and oligodendrocyte survival in rat models of focal ischemia

Human umbilical cord blood (HUCB) cells have shown efficacy in rodent models of focal ischemia and in vitro systems that recapitulate stroke conditions. One potential mechanism of protection is through secretion of soluble factors that protect neurons and oligodendrocytes (OLs) from oxidative stress. To overcome practical issues with cellular therapies, identification of soluble factors released by HUCB and other stem cells may pave the way for treatment modalities that are safer for a larger percentage of stroke patients. Among these soluble factors is leukemia inhibitory factor (LIF), a cytokine that exerts pleiotropic effects on cell survival. Here, data show that LIF effectively reduced infarct volume, reduced white matter injury and improved functional outcomes when administered to rats following permanent middle cerebral artery occlusion. To further explore downstream signaling, primary oligodendrocyte cultures were exposed to oxygen-glucose deprivation to mimic stroke conditions. LIF significantly reduced lactate dehydrogenase release from OLs, reduced superoxide dismutase activity and induced peroxiredoxin 4 (Prdx4) transcript. Additionally, the protective and antioxidant capacity of LIF was negated by both Akt inhibition and co-incubation with Prdx4-neutralising antibodies, establishing a role for the Akt signaling pathway and Prdx4-mediated antioxidation in LIF protection.

Role of nuclear factor kappa B in central nervous system regeneration

Activation of nuclear factor kappa B (NF-κB) is a hallmark of various central nervous system (CNS) pathologies. Neuron-specific inhibition of its transcriptional activator subunit RelA, also referred to as p65, promotes neuronal survival under a range of conditions, i.e., for ischemic or excitotoxic insults. In macro- and microglial cells, post-lesional activation of NF-κB triggers a growth-permissive program which contributes to neural tissue inflammation, scar formation, and the expression of axonal growth inhibitors. Intriguingly, inhibition of such inducible NF-κB in the neuro-glial compartment, i.e., by genetic ablation of RelA or overexpression of a transdominant negative mutant of its upstream regulator IκBα, significantly enhances functional recovery and promotes axonal regeneration in the mature CNS. By contrast, depletion of the NF-κB subunit p50, which lacks transcriptional activator function and acts as a transcriptional repressor on its own, causes precocious neuronal loss and exacerbates axonal degeneration in the lesioned brain. Collectively, the data imply that NF-κB orchestrates a multicellular program in which κB-dependent gene expression establishes a growth-repulsive terrain within the post-lesioned brain that limits structural regeneration of neuronal circuits. Considering these subunit-specific functions, interference with the NF-κB pathway might hold clinical potentials to improve functional restoration following traumatic CNS injury.

Gastrodin promotes the secretion of brain-derived neurotrophic factor in the injured spinal cord

Gastrodin, an active component of tall gastrodia tuber, is widely used in the treatment of dizziness, paralysis, epilepsy, stroke and dementia, and exhibits a neuroprotective effect. A rat model of spinal cord injury was established using Allen's method, and gastrodin was administered via the subarachnoid cavity and by intraperitoneal injection for 7 days. Results show that gastrodin promoted the secretion of brain-derived neurotrophic factor in rats with spinal cord injury. After gastrodin treatment, the maximum angle of the inclined plane test, and the Basso, Beattie and Bresnahan scores increased. Moreover, gastrodin improved neural tissue recovery in the injured spinal cord. These results demonstrate that gastrodin promotes the secretion of brain-derived neurotrophic factor, contributes to the recovery of neurological function, and protects neural cells against injury.

The behavior-analytic origins of constraint-induced movement therapy: an example of behavioral neurorehabilitation

Constraint-induced (CI) therapy is a term given to a family of efficacious neurorehabilitation treatments including to date: upper extremity CI movement therapy, lower extremity CI movement therapy, pediatric CI therapy, and CI aphasia therapy. The purpose of this article is to outline the behavior analysis origins of CI therapy and the ways in which its procedures incorporate behavior analysis methods and principles. The intervention is founded on the concept of learned nonuse, a mechanism now empirically demonstrated to exist, which occurs after many different types of damage to the central nervous system (CNS). It results from the dramatic alteration of the contingencies of reinforcement that results from substantial CNS damage and leads to a greater deficit than is warranted by the actual damage sustained. CI therapy produces a countervailing alteration in the contingencies of reinforcement. The intervention has been used successfully to substantially improve motor deficits after stroke, traumatic brain injury, spinal cord injury, multiple sclerosis, with cerebral palsy in a pediatric population, and for language impairment in poststroke aphasia. The protocol of CI therapy consists primarily of standard behavior-analytic methods. It produces a marked plastic brain change that is correlated with its therapeutic effect, and therefore provides an example of the way in which behavior change can contribute to a profound remodeling of the brain. CI therapy may be viewed as an example of behavioral neurorehabilitation.