Absence of enhancement in a lesion does not preclude primary central nervous system T-cell lymphoma:A case report

BACKGROUND Primary central nervous system lymphoma(PCNSL)is a non-Hodgkin lymphoma that originates in the central nervous system(CNS)and is exclusively limited to the CNS.Although most PCNSLs are diffuse large B-cell lymphomas,primary CNS T-cell lymphomas(PCNSTLs)are rare.PCNSTLs typically demonstrate some degree of enhancement on contrast-enhanced magnetic resonance imaging(MRI).To the best of our knowledge,non-enhancing PCNSTL has not been reported previously.CASE SUMMARY A 69-year-old male presented to the neurology department with complaints of mild cognitive impairment and gradual onset of left lower leg weakness over a span of two weeks.Initial MRI showed asymmetric T2-hyperintense lesions within the brain.No enhancement was observed on the contrast-enhanced T1 image.The initial diagnosis was neuro-Behçet’s disease.Despite high-dose steroid therapy,no alterations in the lesions were identified on initial MRI.The patient’s symptoms deteriorated further.An MRI performed one month after the initial scan revealed an increased lesion extent.Subsequently,brain biopsy confirmed the diagnosis of PCNSTL.The patient underwent definitive combined chemoradiotherapy.However,the patient developed bacteremia and died of septic shock approximately three months after diagnosis.CONCLUSION The absence of enhancement in the lesion did not rule out PCNSTL.A biopsy approach is advisable for pathological confirmation.

Intranasal administration of stem cell-derived exosomes for central nervous system diseases

Exosomes,lipid bilayer-enclosed small cellular vesicles,are actively secreted by various cells and play crucial roles in intercellular communication.These nanosized vesicles transport internalized proteins,mRNA,miRNA,and other bioactive molecules.Recent findings have provided compelling evidence that exosomes derived from stem cells hold great promise as a therapeutic modality for central nervous system disorders.These exosomes exhibit multifaceted properties including antiapoptotic,anti-inflammatory,neurogenic,and vasculogenic effects.Furthermore,exosomes offer several advantages over stem cell therapy,such as high preservation capacity,low immunogenicity,the ability to traverse the blood-brain barrier,and the potential for drug encapsulation.Consequently,researchers have turned their attention to exosomes as a novel therapeutic avenue.Nonetheless,akin to the limitations of stem cell treatment,the limited accumulation of exosomes in the injured brain poses a challenge to their clinical application.To overcome this hurdle,intranasal administration has emerged as a non-invasive and efficacious route for delivering drugs to the central nervous system.By exploiting the olfactory and trigeminal nerve axons,this approach enables the direct transport of therapeutics to the brain while bypassing the blood-brain barrier.Notably,exosomes,owing to their small size,can readily access the nerve pathways using this method.As a result,intranasal administration has gained increasing recognition as an optimal therapeutic strategy for exosomebased treatments.In this comprehensive review,we aim to provide an overview of both basic and clinical research studies investigating the intranasal administration of exosomes for the treatment of central nervous system diseases.Furthermore,we elucidate the underlying therapeutic mechanisms and offer insights into the prospect of this approach.

Crosstalk among mitophagy,pyroptosis,ferroptosis,and necroptosis in central nervous system injuries

Central nervous system injuries have a high rate of resulting in disability and mortality;however,at present,effective treatments are lacking.Programmed cell death,which is a genetically determined fo rm of active and ordered cell death with many types,has recently attra cted increasing attention due to its functions in determining the fate of cell survival.A growing number of studies have suggested that programmed cell death is involved in central nervous system injuries and plays an important role in the progression of brain damage.In this review,we provide an ove rview of the role of programmed cell death in central nervous system injuries,including the pathways involved in mitophagy,pyroptosis,ferroptosis,and necroptosis,and the underlying mechanisms by which mitophagy regulates pyroptosis,ferroptosis,and necro ptosis.We also discuss the new direction of therapeutic strategies to rgeting mitophagy for the treatment of central nervous system injuries,with the aim to determine the connection between programmed cell death and central nervous system injuries and to identify new therapies to modulate programmed cell death following central nervous system injury.In conclusion,based on these properties and effects,interventions targeting programmed cell death could be developed as potential therapeutic agents for central nervous system injury patients.

Oligodendrocytes in central nervous system diseases:the effect of cytokine regulation

Cytokines including tumor necrosis factor, interleukins, interferons, and chemokines are abundantly produced in various diseases. As pleiotropic factors, cytokines are involved in nearly every aspect of cellular functions such as migration, survival, proliferation, and differentiation. Oligodendrocytes are the myelin-forming cells in the central nervous system and play critical roles in the conduction of action potentials, supply of metabolic components for axons, and other functions. Emerging evidence suggests that both oligodendrocytes and oligodendrocyte precursor cells are vulnerable to cytokines released under pathological conditions. This review mainly summarizes the effects of cytokines on oligodendrocyte lineage cells in central nervous system diseases. A comprehensive understanding of the effects of cytokines on oligodendrocyte lineage cells contributes to our understanding of central nervous system diseases and offers insights into treatment strategies.

Role of CD36 in central nervous system diseases

CD36 is a highly glycosylated integral membrane protein that belongs to the scavenger receptor class B family and regulates the pathological progress of metabolic diseases.CD36 was recently found to be widely expressed in various cell types in the nervous system,including endothelial cells,pericytes,astrocytes,and microglia.CD36 mediates a number of regulatory processes,such as endothelial dysfunction,oxidative stress,mitochondrial dysfunction,and inflammatory responses,which are involved in many central nervous system diseases,such as stroke,Alzheimer’s disease,Parkinson’s disease,and spinal cord injury.CD36 antagonists can suppress CD36 expression or prevent CD36 binding to its ligand,thereby achieving inhibition of CD36-mediated pathways or functions.Here,we reviewed the mechanisms of action of CD36 antagonists,such as Salvianolic acid B,tanshinone IIA,curcumin,sulfosuccinimidyl oleate,antioxidants,and small-molecule compounds.Moreover,we predicted the structures of binding sites between CD36 and antagonists.These sites can provide targets for more efficient and safer CD36 antagonists for the treatment of central nervous system diseases.

Microglia lactylation in relation to central nervous system diseases

The development of neurodegenerative diseases is closely related to the disruption of central nervous system homeostasis.Microglia,as innate immune cells,play important roles in the maintenance of central nervous system homeostasis,injury response,and neurodegenerative diseases.Lactate has been considered a metabolic waste product,but recent studies are revealing ever more of the physiological functions of lactate.Lactylation is an important pathway in lactate function and is involved in glycolysis-related functions,macrophage polarization,neuromodulation,and angiogenesis and has also been implicated in the development of various diseases.This review provides an overview of the lactate metabolic and homeostatic regulatory processes involved in microglia lactylation,histone versus non-histone lactylation,and therapeutic approaches targeting lactate.Finally,we summarize the current research on microglia lactylation in central nervous system diseases.A deeper understanding of the metabolic regulatory mechanisms of microglia lactylation will provide more options for the treatment of central nervous system diseases.

Role of copper in central nervous system physiology and pathology

Copper is a transition metal and an essential element for the organism,as alterations in its homeostasis leading to metal accumulation or deficiency have pathological effects in several organs,including the central nervous system.Central copper dysregulations have been evidenced in two genetic disorders characterized by mutations in the copper-ATPases ATP7A and ATP7B,Menkes disease and Wilson’s disease,respectively,and also in multifactorial neurological disorders such as Alzheimer’s disease,Parkinson’s disease,amyotrophic lateral sclerosis,and multiple sclerosis.This review summarizes current knowledge about the role of copper in central nervous system physiology and pathology,reports about unbalances in copper levels and/or distribution under disease,describes relevant animal models for human disorders where copper metabolism genes are dysregulated,and discusses relevant therapeutic approaches modulating copper availability.Overall,alterations in copper metabolism may contribute to the etiology of central nervous system disorders and represent relevant therapeutic targets to restore tissue homeostasis.

Heterogeneity of mature oligodendrocytes in the central nervous system

Mature oligodendrocytes form myelin sheaths that are crucial for the insulation of axons and efficient signal transmission in the central nervous system.Recent evidence has challenged the classical view of the functionally static mature oligodendrocyte and revealed a gamut of dynamic functions such as the ability to modulate neuronal circuitry and provide metabolic support to axons.Despite the recognition of potential heterogeneity in mature oligodendrocyte function,a comprehensive summary of mature oligodendrocyte diversity is lacking.We delve into early 20th-century studies by Robertson and Río-Hortega that laid the foundation for the modern identification of regional and morphological heterogeneity in mature oligodendrocytes.Indeed,recent morphologic and functional studies call into question the long-assumed homogeneity of mature oligodendrocyte function through the identification of distinct subtypes with varying myelination preferences.Furthermore,modern molecular investigations,employing techniques such as single cell/nucleus RNA sequencing,consistently unveil at least six mature oligodendrocyte subpopulations in the human central nervous system that are highly transcriptomically diverse and vary with central nervous system region.Age and disease related mature oligodendrocyte variation denotes the impact of pathological conditions such as multiple sclerosis,Alzheimer's disease,and psychiatric disorders.Nevertheless,caution is warranted when subclassifying mature oligodendrocytes because of the simplification needed to make conclusions about cell identity from temporally confined investigations.Future studies leveraging advanced techniques like spatial transcriptomics and single-cell proteomics promise a more nuanced understanding of mature oligodendrocyte heterogeneity.Such research avenues that precisely evaluate mature oligodendrocyte heterogeneity with care to understand the mitigating influence of species,sex,central nervous system region,age,and disease,hold promise for the development of therapeutic interventions targeting varied central nervous system pathology.

High mobility group box 1 in the central nervous system:regeneration hidden beneath inflammation

High-mobility group box 1 was first discovered in the calf thymus as a DNA-binding nuclear protein and has been widely studied in diverse fields,including neurology and neuroscience.High-mobility group box 1 in the extracellular space functions as a pro-inflammatory damage-associated molecular pattern,which has been proven to play an important role in a wide variety of central nervous system disorders such as ischemic stroke,Alzheimer’s disease,frontotemporal dementia,Parkinson’s disease,multiple sclerosis,epilepsy,and traumatic brain injury.Several drugs that inhibit high-mobility group box 1 as a damage-associated molecular pattern,such as glycyrrhizin,ethyl pyruvate,and neutralizing anti-high-mobility group box 1 antibodies,are commonly used to target high-mobility group box 1 activity in central nervous system disorders.Although it is commonly known for its detrimental inflammatory effect,high-mobility group box 1 has also been shown to have beneficial pro-regenerative roles in central nervous system disorders.In this narrative review,we provide a brief summary of the history of high-mobility group box 1 research and its characterization as a damage-associated molecular pattern,its downstream receptors,and intracellular signaling pathways,how high-mobility group box 1 exerts the repair-favoring roles in general and in the central nervous system,and clues on how to differentiate the pro-regenerative from the pro-inflammatory role.Research targeting high-mobility group box 1 in the central nervous system may benefit from differentiating between the two functions rather than overall suppression of high-mobility group box 1.

Meningeal lymphatic vessel crosstalk with central nervous system immune cells in aging and neurodegenerative diseases

Meningeal lymphatic vessels form a relationship between the nervous system and periphery, which is relevant in both health and disease. Meningeal lymphatic vessels not only play a key role in the drainage of brain metabolites but also contribute to antigen delivery and immune cell activation. The advent of novel genomic technologies has enabled rapid progress in the characterization of myeloid and lymphoid cells and their interactions with meningeal lymphatic vessels within the central nervous system. In this review, we provide an overview of the multifaceted roles of meningeal lymphatic vessels within the context of the central nervous system immune network, highlighting recent discoveries on the immunological niche provided by meningeal lymphatic vessels. Furthermore, we delve into the mechanisms of crosstalk between meningeal lymphatic vessels and immune cells in the central nervous system under both homeostatic conditions and neurodegenerative diseases, discussing how these interactions shape the pathological outcomes. Regulation of meningeal lymphatic vessel function and structure can influence lymphatic drainage, cerebrospinal fluid-borne immune modulators, and immune cell populations in aging and neurodegenerative disorders, thereby playing a key role in shaping meningeal and brain parenchyma immunity.

Liposomes as versatile agents for the management of traumatic and nontraumatic central nervous system disorders:drug stability,targeting efficiency,and safety

Various nanoparticle-based drug delivery systems for the treatment of neurological disorders have been widely studied.However,their inability to cross the blood–brain barrier hampers the clinical translation of these therapeutic strategies.Liposomes are nanoparticles composed of lipid bilayers,which can effectively encapsulate drugs and improve drug delivery across the blood–brain barrier and into brain tissue through their targeting and permeability.Therefore,they can potentially treat traumatic and nontraumatic central nervous system diseases.In this review,we outlined the common properties and preparation methods of liposomes,including thin-film hydration,reverse-phase evaporation,solvent injection techniques,detergent removal methods,and microfluidics techniques.Afterwards,we comprehensively discussed the current applications of liposomes in central nervous system diseases,such as Alzheimer's disease,Parkinson's disease,Huntington's disease,amyotrophic lateral sclerosis,traumatic brain injury,spinal cord injury,and brain tumors.Most studies related to liposomes are still in the laboratory stage and have not yet entered clinical trials.Additionally,their application as drug delivery systems in clinical practice faces challenges such as drug stability,targeting efficiency,and safety.Therefore,we proposed development strategies related to liposomes to further promote their development in neurological disease research.

High-dose methotrexate and zanubrutinib combination therapy for primary central nervous system lymphoma

In this editorial I comment on the article,published in the current issue of the World Journal of Clinical Oncology.Primary central nervous system lymphoma(PCNSL)is a disease of elderly and immunocompromised patients.The authors reported clinical results of 19 patients with PCNSL treated with zanubrutinib/high dose methotrexate(HD-MTX)until disease progression.They demonstrated that the combination of zanubrutinib with HD-MTX led to a marked clinical response and tolerability among these patients.They also observed that cerebrospinal fluid liquid biopsy to detect circulating tumor DNA may be a good option for evaluating treatment response and tumor burden in patients with PCNSL.PCNSL is a challenging disease for treatment as these patients present with different neurological states and comorbidities.Treatment has evolved over the years from whole brain radiotherapy to HD-MTX followed by autologous stem cell transplant.Gradually,treatment of patients with PCNSL is going to become individualized.

Bruton’s tyrosine kinase inhibitors in primary central nervous system lymphoma:New hopes on the horizon

In this editorial,we comment on the article by Wang et al.This manuscript explores the potential synergistic effects of combining zanubrutinib,a novel oral inhibitor of Bruton’s tyrosine kinase,with high-dose methotrexate(HD-MTX)as a therapeutic intervention for primary central nervous system lymphoma(PCNSL).The study involves a retrospective analysis of 19 PCNSL patients,highlighting clinicopathological characteristics,treatment outcomes,and genomic biomarkers.The results indicate the combination’s good tolerance and strong antitumor activity,with an 84.2%overall response rate.The authors emphasize the potential of zanubrutinib to modulate key genomic features of PCNSL,particularly mutations in myeloid differentiation primary response 88 and cluster of differentiation 79B.Furthermore,the study investigates the role of circulating tumor DNA in cerebrospinal fluid for disease surveillance and treatment response monitoring.In essence,the study provides valuable insights into the potential of combining zanubrutinib with HD-MTX as a frontline therapeutic regimen for PCNSL.The findings underscore the importance of exploring alternative treatment modalities and monitoring genomic and liquid biopsy markers to optimize patient outcomes.While the findings suggest promise,the study’s limitations should be considered,and further research is needed to establish the clinical relevance of this therapeutic approach for PCNSL.

A case of primary angiitis of the central nervous system diagnosed and treated based on HR-MRI

Objective:To summarize the clinical features,imaging manifestations,therapeutic options,and prognosis of the primary angiitis of the central nervous system(PACNS)and to explore the role of high-resolution magnetic resonance imaging(HR-MRI)in the PACNS diagnosis and treatment.Methods:One patient with PACNS treated by HR-MRI was retrospectively analyzed and summarized by combining relevant literature.Results:The patient was a young female who was hospitalized with progressive cerebral infarction and multiple intracranial arterial stenosis.HR-MRI indicated vasculitic changes.After excluding other diseases,hormone shock combined with immunosuppression was given,followed by long-term rehabilitation treatment.The patient’s condition tended to stabilize,and the prognosis was satisfactory.Conclusion PACNS is challenging to diagnose and is characterized by poor prognosis and easy recurrence.HR-MRI plays an important role in the clinical diagnosis and treatment adjustment for PACNS.

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.

Mesenchymal stem cell-derived exosomes regulate microglia phenotypes:a promising treatment for acute central nervous system injury

There is growing evidence that long-term central nervous system(CNS)inflammation exacerbates secondary deterioration of brain structures and functions and is one of the major determinants of disease outcome and progression.In acute CNS injury,brain microglia are among the first cells to respond and play a critical role in neural repair and regeneration.However,microglial activation can also impede CNS repair and amplify tissue damage,and phenotypic transformation may be responsible for this dual role.Mesenchymal stem cell(MSC)-derived exosomes(Exos)are promising therapeutic agents for the treatment of acute CNS injuries due to their immunomodulatory and regenerative properties.MSC-Exos are nanoscale membrane vesicles that are actively released by cells and are used clinically as circulating biomarkers for disease diagnosis and prognosis.MSC-Exos can be neuroprotective in several acute CNS models,including for stroke and traumatic brain injury,showing great clinical potential.This review summarized the classification of acute CNS injury disorders and discussed the prominent role of microglial activation in acute CNS inflammation and the specific role of MSC-Exos in regulating pro-inflammatory microglia in neuroinflammatory repair following acute CNS injury.Finally,this review explored the potential mechanisms and factors associated with MSCExos in modulating the phenotypic balance of microglia,focusing on the interplay between CNS inflammation,the brain,and injury aspects,with an emphasis on potential strategies and therapeutic interventions for improving functional recovery from early CNS inflammation caused by acute CNS injury.

The effects and potential of microglial polarization and crosstalk with other cells of the central nervous system in the treatment of Alzheimer’s disease

Microglia are resident immune cells in the central nervous system. During the pathogenesis of Alzheimer’s disease, stimulatory factors continuously act on the microglia causing abnormal activation and unbalanced phenotypic changes;these events have become a significant and promising area of research. In this review, we summarize the effects of microglial polarization and crosstalk with other cells in the central nervous system in the treatment of Alzheimer’s disease. Our literature search found that phenotypic changes occur continuously in Alzheimer’s disease and that microglia exhibit extensive crosstalk with astrocytes, oligodendrocytes, neurons, and penetrated peripheral innate immune cells via specific signaling pathways and cytokines. Collectively, unlike previous efforts to modulate microglial phenotypes at a single level, targeting the phenotypes of microglia and the crosstalk with other cells in the central nervous system may be more effective in reducing inflammation in the central nervous system in Alzheimer’s disease. This would establish a theoretical basis for reducing neuronal death from central nervous system inflammation and provide an appropriate environment to promote neuronal regeneration in the treatment of Alzheimer’s disease.

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.Howeve r,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 resto ration 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 selfrenewal 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 fa cilitate the successful application of neural stem cells in central nervous system injuries.

Mesenchymal stem cell-derived extracellular vesicles therapy in traumatic central nervous system diseases:a systematic review and meta-analysis

Although there are challenges in treating traumatic central nervous system diseases,mesenchymal stem cell-de rived extracellular vesicles(MSC-EVs) have recently proven to be a promising non-cellular the rapy.We comprehensively evaluated the efficacy of mesenchymal stem cell-de rived extracellular vesicles in traumatic central nervous system diseases in this meta-analysis based on preclinical studies.Our meta-analysis was registered at PROSPERO(CRD42022327904,May 24,2022).To fully retrieve the most relevant articles,the following databases were thoro ughly searched:PubMed,Web of Science,The Cochrane Library,and Ovid-Embase(up to April 1,2022).The included studies were preclinical studies of mesenchymal stem cell-derived extracellular vesicles for traumatic central nervous system diseases.The Systematic Review Centre for Laboratory Animal Experimentation(SYRCLE)’s risk of bias tool was used to examine the risk of publication bias in animal studies.After screening 2347studies,60 studies were included in this study.A meta-analysis was conducted for spinal co rd injury(n=52) and traumatic brain injury(n=8).The results indicated that mesenchymal stem cell-derived extracellular vesicles treatment prominently promoted motor function recovery in spinal co rd injury animals,including rat Basso,Beattie and Bresnahan locomotor rating scale scores(standardized mean difference [SMD]:2.36,95% confidence interval [CI]:1.96-2.76,P <0.01,I2=71%) and mouse Basso Mouse Scale scores(SMD=2.31,95% CI:1.57-3.04,P=0.01,I2=60%) compared with controls.Further,mesenchymal stem cell-de rived extracellular vesicles treatment significantly promoted neurological recovery in traumatic brain injury animals,including the modified N eurological Severity Score(SMD=-4.48,95% CI:-6.12 to-2.84,P <0.01,I2=79%) and Foot Fault Test(SMD=-3.26,95% CI:-4.09 to-2.42,P=0.28,I2=21%) compared with controls.Subgroup analyses showed that characteristics may be related to the therapeutic effect of mesenchymal stem cell-de rived extra cellular vesicles.For Basso,Beattie and Bresnahan locomotor rating scale scores,the efficacy of allogeneic mesenchymal stem cell-derived extracellular vesicles was higher than that of xenogeneic mesenchymal stem cell-derived extracellular vesicles(allogeneic:SMD=2.54,95% CI:2.05-3.02,P=0.0116,I2=65.5%;xenogeneic:SMD:1.78,95%CI:1.1-2.45,P=0.0116,I2=74.6%).Mesenchymal stem cellde rived extracellular vesicles separated by ultrafiltration centrifugation combined with density gradient ultra centrifugation(SMD=3.58,95% CI:2.62-4.53,P <0.0001,I2=31%) may be more effective than other EV isolation methods.For mouse Basso Mouse Scale scores,placenta-derived mesenchymal stem cell-de rived extracellular vesicles worked better than bone mesenchymal stem cell-derived extracellular vesicles(placenta:SMD=5.25,95% CI:2.45-8.06,P=0.0421,I2=0%;bone marrow:SMD=1.82,95% CI:1.23-2.41,P=0.0421,I2=0%).For modified Neurological Severity Score,bone marrow-derived MSC-EVs worked better than adipose-derived MSC-EVs(bone marrow:SMD=-4.86,95% CI:-6.66 to-3.06,P=0.0306,I2=81%;adipose:SMD=-2.37,95% CI:-3.73 to-1.01,P=0.0306,I2=0%).Intravenous administration(SMD=-5.47,95% CI:-6.98 to-3.97,P=0.0002,I2=53.3%) and dose of administration equal to 100 μg(SMD=-5.47,95% CI:-6.98 to-3.97,P <0.0001,I2=53.3%)showed better res ults than other administration routes and doses.The heterogeneity of studies was small,and sensitivity analysis also indicated stable results.Last,the methodological quality of all trials was mostly satisfactory.In conclusion,in the treatment of traumatic central nervous system diseases,mesenchymal stem cell-derived extracellular vesicles may play a crucial role in promoting motor function recovery.

In vivo astrocyte-to-neuron reprogramming for central nervous system regeneration:a narrative review

The inability of damaged neurons to regenerate within the mature central nervous system(CNS)is a significant neuroscientific challenge.Astrocytes are an essential component of the CNS and participate in many physiological processes including blood-brain barrier formation,axon growth regulation,neuronal support,and higher cognitive functions such as memory.Recent reprogramming studies have confirmed that astrocytes in the mature CNS can be transformed into functional neurons.Building on in vitro work,many studies have demonstrated that astrocytes can be transformed into neurons in different disease models to replace damaged or lost cells.However,many findings in this field are controversial,as the source of new neurons has been questioned.This review summarizes progress in reprogramming astrocytes into neurons in vivo in animal models of spinal cord injury,brain injury,Huntington’s disease,Parkinson’s disease,Alzheimer’s disease,and other neurodegenerative conditions.