Search Results (90)

The application of artificial intelligence through the brain–computer interface (BCI) is proving to be one of the great advances in neuroscience today. The development of surface electrodes over the cortex and very fine electrodes that can be stereotactically implanted in the brain have moved the science forward to the extent that paralyzed people can play chess and blind people can read letters. However, the introduction of foreign bodies into deeper parts of the central nervous system results in foreign body reaction, scarring, apoptosis, and decreased signaling. Implanted electrodes activate microglia, causing the release of inflammatory factors, the recruitment of systemic inflammatory cells to the site of injury, and ultimately glial scarring and the encapsulation of the electrode. Recordings historically fail between 6 months and 1 year; the longest BCI in use has been 7 years. This article proposes a biomolecular strategy provided by angiogenic cell precursors (ACPs) and nerve cell precursors (NCPs), administered intrathecally. This combination of cells is anticipated to sustain and promote learning across the BCI. Together, through the downstream activation of neurotrophic factors, they may exert a salutary immunomodulatory suppression of inflammation, anti-apoptosis, homeostasis, angiogenesis, differentiation, synaptogenesis, neuritogenesis, and learning-associated plasticity. Full article

Background/Objectives: The incidence and prevalence of ischemic stroke, a leading cause of death and disability worldwide, are significantly higher in older adults than in younger individuals. Senescence induces a variety of biological changes that influence the pathogenesis of diseases such as ischemic stroke, thereby necessitating age-specific medical treatments. However, the molecular mechanisms underlying age-related differences in ischemic stroke progression remain poorly understood. Methods: We compared the histological and molecular features of ischemic stroke in a photothrombotic mouse model, focusing on 9-week-old (young) and 90-week-old (old) mice. Results: We found that microglial accumulation at the infarct region of the cerebral cortex was significantly lower in old mice than in young ones. This reduction in the microglial response was accompanied by a decrease in the morphological robustness of the astrocytes forming the glial scar. Furthermore, the mRNA expression of proinflammatory cytokines CXCL10, CCL2, and TNF-α, which were upregulated in the infarct region, was considerably higher in the old mice than in the young ones. Cytokine expression was well correlated with the mRNA levels of Toll-like receptor 4 (TLR4), a key regulator of neuroinflammation in old mice, but less correlated with them in young mice. Interestingly, Tlr4 mRNA expression in young mice was negatively correlated with the mRNA expression of the epigenetic regulator HDAC7, whereas this correlation was positive in old mice. Conclusions: These findings suggest that age-dependent changes in epigenetic regulation, such as the interaction between HDAC7 and TLR4, may contribute to the distinct pathological progression of ischemic stroke in older individuals. Full article

Intracerebral hemorrhage (ICH), a severe stroke subtype common in the elderly, often results in high morbidity and mortality, with limited treatment options for long-term recovery. While glial scar formation is increasingly recognized as key to central nervous system (CNS) repair, its role and characteristics in the aging brain post-ICH remain unclear. This study investigated glial scar formation after ICH (100 μL autologous blood injected into the right basal ganglia model) in aged Fischer 344 rats and assessed the effects of deferoxamine (DFX) treatment. Histological and immunohistochemical analyses were conducted on days 7, 28, and 60 post-ICH using cell-specific and iron-related markers, with DFX administered at 100 mg/kg daily for 14 days in separate groups. Over time, the lesion core showed increased hemosiderin accumulation and astrogliosis. By day 60, the area of astrogliosis corresponded to an area with persistent neuronal loss (DARPP-32-negative). Glial composition shifted from microglia dominance on day 28 to astrocyte predominance by day 60. DFX treatment reduced iron deposition, astrogliosis, and DARPP-32-negative regions while enhancing oligodendrocyte presence. Iron-related markers (HO-1, ferritin, Perls’ staining) and PDGFRβ-positive fibrotic cells were concentrated in the scar core. These findings provide novel insights into scar formation after ICH in aged rats and suggest DFX as a potential therapy to improve outcomes in elderly stroke patients. Full article

Spinal cord injury (SCI) remains one of the toughest obstacles in neuroscience and regenerative medicine due to both severe functional loss and limited healing ability. This article aims to provide a key integrative, mechanism-focused review of the molecular landscape of SCI and the new disruptive therapy technologies that are now evolving in the SCI arena. Our goal is to unify a fundamental pathophysiology of neuroinflammation, ferroptosis, glial scarring, and oxidative stress with the translation of precision treatment approaches driven by artificial intelligence (AI), CRISPR-mediated gene editing, and regenerative bioengineering. Drawing upon advances in single-cell omics, systems biology, and smart biomaterials, we will discuss the potential for reprogramming the spinal cord at multiple levels, from transcriptional programming to biomechanical scaffolds, to change the course from an irreversible degeneration toward a directed regenerative pathway. We will place special emphasis on using AI to improve diagnostic/prognostic and inferred responses, gene and cell therapies enabled by genomic editing, and bioelectronics capable of rehabilitating functional connectivity. Although many of the technologies described below are still in development, they are becoming increasingly disruptive capabilities of what it may mean to recover from an SCI. Instead of prescribing a particular therapeutic fix, we provide a future-looking synthesis of interrelated biological, computational, and bioengineering approaches that conjointly chart a course toward adaptive, personalized neuroregeneration. Our intent is to inspire a paradigm shift to resolve paralysis through precision recovery and to be grounded in a spirit of humility, rigor, and an interdisciplinary approach. Full article

Spinal cord injury (SCI) is a debilitating neurological condition that leads to severe disabilities, significantly reducing patients’ quality of life and imposing substantial societal and economic burdens. SCI involves a complex pathogenesis, including primary irreversible damage and secondary injury driven by neuroinflammation, apoptosis, and ischemia. Current treatments often provide limited efficacy, underscoring the urgent need for innovative therapeutic strategies. This paper aims to explore the potential use of stem cell (SC) therapy and exosome-based treatments as transformative approaches for managing SCI and mitigating associated disabilities. SCs, such as mesenchymal stem cells (MSCs), neural stem cells (NSCs), and embryonic stem cells (ESCs), demonstrate regenerative capabilities, including self-renewal, differentiation into neurons and glial cells, and modulation of the injury microenvironment. These properties enable SCs to reduce inflammation, inhibit apoptosis, and promote neuronal regeneration in preclinical models. Exosome-based therapies, derived from SCs, offer a novel alternative by addressing challenges like immune rejection and tumorigenicity. Exosomes deliver biomolecules, such as miRNAs, fostering anti-inflammatory, anti-apoptotic, and pro-regenerative effects. They have shown efficacy in improving motor function, reducing glial scarring, and enhancing axonal regrowth in SCI models. The objective of this paper is to provide a comprehensive review of SC therapy and exosome-based approaches, emphasizing their potential to revolutionize SCI management while addressing ethical concerns, immune rejection, and the need for large-scale clinical trials. These therapies hold promise for improving recovery outcomes and alleviating the profound disabilities associated with SCI. Full article

Traumatic brain injury (TBI) has a complex and multifactorial pathology and is a major cause of death and disability for humans. Immediately after TBI, astrocytes and microglia react with complex morphological and functional changes known as reactive gliosis to form a glial scar in the area immediately adjacent to the lesion, which is the major barrier to neuronal regeneration. The flavonoid agathisflavone (bis-apigenin), present in Poincianella pyramidalis leaves, has been shown to have neuroprotective, neurogenic, and anti-inflammatory effects, demonstrated in vitro models of glutamate-induced toxicity, neuroinflammation, and demyelination. In this study, we evaluated the effect and mechanisms of agathisflavone in neuronal integrity and in the modulation of gliosis in an ex vivo model of TBI. For this, microdissections from the encephalon of Wistar rats (P6-8) were prepared and subjected to mechanical injury (MI) and treated or not with daily agathisflavone (5 μM) for 3 days. Astrocyte reactivity was investigated by measuring mRNA and expression of GFAP protein in the lesioned area by immunofluorescence and Western blot. The proportion of microglia was determined by immunofluorescence for Iba-1; mRNA expression for inflammasome NRPL3 and interleukin-1 beta (IL-1β) was determined by RT-qPCR. It was observed that lesions in the cortical tissue induced astrocytes overexpressing GFAP in the typical glial scar formed and that agathisflavone modulated GFAP expression at the transcriptional and post-transcriptional levels, which was associated with a reduction of the glial scar. MI induced an increase in the proportion of microglia (Iba-1+), which was not observed in agathisflavone-treated cultures. Moreover, the flavonoid modulated negatively both the NRLP3 and IL-1β mRNA expression that was increased in the lesioned area of the tissue. These findings support the regulatory properties of agathisflavone in the control of the inflammatory response in glial cells, which can impact neuroprotection and should be considered for future studies for TB and other pathological conditions of the central nervous system. Full article

Rhegmatogenous retinal detachment (RRD) is a sight-threatening condition involving retinal detachment and the accumulation of fluid in the subretinal space. Proliferative vitreoretinopathy (PVR) is a pathologic complication that develops after RRD surgery, and approximately 5–10% of RRD cases develop post-operative PVR. Prolonged inflammation in the wound healing process, epithelial–mesenchymal transition (EMT), retinal pigment epithelial (RPE) cell migration and proliferation, and epiretinal, intraretinal, and subretinal fibrosis are typical in the formation of PVR. RPE cells undergo EMT and become fibroblast-like cells that migrate to the retina and vitreous, promoting PVR formation. Fibroblasts transform into myofibroblasts, which promote fibrosis by overproducing the extracellular matrix (ECM). RPE cells, fibroblasts, glial cells, macrophages, T lymphocytes, and increased ECM production form contractile epiretinal membranes. Cytokine release, complement activation, RPE cells, glial cells, and endothelial cells are all involved in retinal immune responses. Normally, wounds heal within 4 to 6 weeks, including hemostasis, inflammation, proliferation, and remodeling phases. Properly initiated inflammation, complement activation, and the function of neutrophils and glial cells heal the wound in the first stage. In a retinal wound, glial cells proliferate and fill the injured area. Gliosis tries to protect the neurons and prevent damage, but it becomes harmful when it causes scarring. If healing is complicated, prolonged inflammation leads to pathological fibrosis. Currently, there is no preventive treatment for the formation of PVR, and it is worth studying in the future. Full article

Background and Objectives: Age-related macular degeneration (AMD) is the leading cause of low vision and legal blindness in adults in developed countries. Wet AMD can be successfully treated using vascular endothelial growth factor (VEGF) inhibitors; however, dry AMD currently has no effective treatment. The purpose of this study is to analyze the efficacy of intraocular injection of plasma rich in growth factors (PRGF) in an AMD mouse model induced by intraperitoneal administration of sodium iodate. Materials and Methods: Intravitreal application of PRGF (experimental group) and saline (control group) was performed immediately after intraperitoneal injection of sodium iodate. Retinographies were performed at 2 and 7 days after treatment administration. The eyes were retrieved for histological and immunohistological analysis. Statistical analysis was performed to compare the outcomes between the study groups. Results: In comparison to saline solution, PRGF significantly decreased the depigmentation of the RPE, showing a more reddened retina. PRGF intravitreal treatment significantly reduced the glial fibrillary acidic protein (GFAP) stained processes, suggesting a significant reduction in the risk of scar formation. Moreover, the myofibroblast invasion into the RPE cell layer was significantly reduced in the PRGF-treated group of mice. There was a tendency for better preservation of the photoreceptors in the PRGF group. Conclusions: Within the limitations of this study, intravitreal injection of PRGF provided significant protection against the degeneration of the photoreceptors and the RPE induced by the systemic administration of NaIO₃. Full article

Background: Reactive astrogliosis and microgliosis are coordinated responses to CNS insults and are pathological hallmarks of traumatic brain injury (TBI). In these conditions, persistent reactive gliosis can impede tissue repopulation and limit neurogenesis. Thus, modulating this phenomenon has been increasingly recognized as potential therapeutic approach. Methods: In this study, we investigated the potential of the flavonoid agathisflavone to modulate astroglial and microglial injury responses and promote neurogenesis in the subventricular zone (SVZ) neurogenic niche. Agathisflavone, or the vehicle in controls, was administered directly into the lateral ventricles in postnatal day (P)8-10 mice by twice daily intracerebroventricular (ICV) injections for 3 days, and brains were examined at P11. Results: In the controls, ICV injection caused glial reactivity along the needle track, characterised immunohistochemically by increased astrocyte expression of glial fibrillary protein (GFAP) and the number of Iba-1+ microglia at the lesion site. Treatment with agathisflavone decreased GFAP expression, reduced both astrocyte reactivity and the number of Iba-1⁺ microglia at the core of the lesion site and the penumbra, and induced a 2-fold increase on the ratio of anti-inflammatory CD206+ to pro-inflammatory CD16/32+ microglia. Notably, agathisflavone increased the population of neuroblasts (GFAP+ type B cells) in all SVZ microdomains by up to double, without significantly increasing the number of neuronal progenitors (DCX+). Conclusions: Although future studies should investigate the underlying molecular mechanisms driving agathisflavone effects on microglial polarization and neurogenesis at different timepoints, these data indicate that agathisflavone could be a potential adjuvant treatment for TBI or central nervous system disorders that have reactive gliosis as a common feature. Full article

Microglia, the resident immune cells of the central nervous system (CNS), play a crucial role in maintaining neural homeostasis but can also contribute to disease and injury when this state is disrupted or conversely play a pivotal role in neurorepair. One way that microglia exert their effects is through the secretion of small vesicles, microglia-derived exosomes (MGEVs). Exosomes facilitate intercellular communication through transported cargoes of proteins, lipids, RNA, and other bioactive molecules that can alter the behavior of the cells that internalize them. Under normal physiological conditions, MGEVs are essential to homeostasis, whereas the dysregulation of their production and/or alterations in their cargoes have been implicated in the pathogenesis of numerous neurodegenerative diseases, including Alzheimer’s disease (AD), Parkinson’s disease (PD), multiple sclerosis (MS), spinal cord injury (SCI), and traumatic brain injury (TBI). In contrast, MGEVs may also offer therapeutic potential by reversing inflammation or being amenable to engineering for the delivery of beneficial biologics or drugs. The effects of MGEVs are determined by the phenotypic state of the parent microglia. Exosomes from anti-inflammatory or pro-regenerative microglia support neurorepair and cell survival by delivering neurotrophic factors, anti-inflammatory mediators, and molecular chaperones. Further, MGEVs can also deliver components like mitochondrial DNA (mtDNA) and proteins to damaged neurons to enhance cellular metabolism and resilience. MGEVs derived from pro-inflammatory microglia can have detrimental effects on neural health. Their cargo often contains pro-inflammatory cytokines, molecules involved in oxidative stress, and neurotoxic proteins, which can exacerbate neuroinflammation, contribute to neuronal damage, and impair synaptic function, hindering neurorepair processes. The role of MGEVs in neurodegeneration and injury—whether beneficial or harmful—largely depends on how they modulate inflammation through the pro- and anti-inflammatory factors in their cargo, including cytokines and microRNAs. In addition, through the propagation of pathological proteins, such as amyloid-beta and alpha-synuclein, MGEVs can also contribute to disease progression in disorders such as AD and PD, or by the transfer of apoptotic or necrotic factors, they can induce neuron toxicity or trigger glial scarring during neurological injury. In this review, we have provided a comprehensive and up-to-date understanding of the molecular mechanisms underlying the multifaceted role of MGEVs in neurological injury and disease. In particular, the role that specific exosome cargoes play in various pathological conditions, either in disease progression or recovery, will be discussed. The therapeutic potential of MGEVs has been highlighted including potential engineering methodologies that have been employed to alter their cargoes or cell-selective targeting. Understanding the factors that influence the balance between beneficial and detrimental exosome signaling in the CNS is crucial for developing new therapeutic strategies for neurodegenerative diseases and neurotrauma. Full article

Despite significant improvements in the comprehension of neuro-regeneration, restoring nerve injury in humans continues to pose a substantial therapeutic difficulty. In the peripheral nervous system (PNS), the nerve regeneration process after injury relies on Schwann cells. These cells play a crucial role in regulating and releasing different extracellular matrix proteins, including laminin and fibronectin, which are essential for facilitating nerve regeneration. However, during regeneration, the nerve is required to regenerate for a long distance and, subsequently, loses its capacity to facilitate regeneration during this progression. Meanwhile, it has been noted that nerve regeneration has limited capabilities in the central nervous system (CNS) compared to in the PNS. The CNS contains factors that impede the regeneration of axons following injury to the axons. The presence of glial scar formation results from this unfavourable condition, where glial cells accumulate at the injury site, generating a physical and chemical barrier that hinders the regeneration of neurons. In contrast to humans, several species, such as axolotls, polychaetes, and planarians, possess the ability to regenerate their neural systems following amputation. This ability is based on the vast amount of pluripotent stem cells that have the remarkable capacity to differentiate and develop into any cell within their body. Although humans also possess these cells, their numbers are extremely limited. Examining the molecular pathways exhibited by these organisms has the potential to offer a foundational understanding of the human regeneration process. This review provides a concise overview of the molecular pathways involved in axolotl, polychaete, and planarian neuro-regeneration. It has the potential to offer a new perspective on therapeutic approaches for neuro-regeneration in humans. Full article

Spinal cord injury (SCI) treatment remains challenging globally, with limited breakthroughs. Tissue engineering offers promise, particularly using acellular spinal cord scaffolds. This study developed a 1-ethyl-(3-dimethylaminopropyl) carbodiimide hydrochloride (EDC)-crosslinked vascular endothelial growth factor (VEGF)-modified acellular spinal cord scaffold for sustained VEGF release. The results show sustained VEGF release over 20 days without altering the scaffold’s properties. Enhanced stability and mechanical properties were observed without increased cytotoxicity. In a rat SCI model, the system improved motor function, reduced glial scarring, and restored spinal cord morphology and histology, indicating potential for SCI therapy. Full article

Traumatic spinal cord injury (tSCI) has complex pathophysiological events that begin after the initial trauma. One such event is fibroglial scar formation by fibroblasts and reactive astrocytes. A strong inhibition of axonal growth is caused by the activated astroglial cells as a component of fibroglial scarring through the production of inhibitory molecules, such as chondroitin sulfate proteoglycans or myelin-associated proteins. Here, we used neural precursor cells (aldynoglia) as promoters of axonal growth and a fibrin hydrogel gelled under alkaline conditions to support and guide neuronal cell growth, respectively. We added Tol-51 sulfoglycolipid as a synthetic inhibitor of astrocyte and microglia in order to test its effect on the axonal growth-promoting function of aldynoglia precursor cells. We obtained an increase in GFAP expression corresponding to the expected glial phenotype for aldynoglia cells cultured in alkaline fibrin. In co-cultures of dorsal root ganglia (DRG) and aldynoglia, the axonal growth promotion of DRG neurons by aldynoglia was not affected. We observed that the neural precursor cells first clustered together and then formed niches from which aldynoglia cells grew and connected to groups of adjacent cells. We conclude that the combination of alkaline fibrin with synthetic sulfoglycolipid Tol-51 increased cell adhesion, cell migration, fasciculation, and axonal growth capacity, promoted by aldynoglia cells. There was no negative effect on the behavior of aldynoglia cells after the addition of sulfoglycolipid Tol-51, suggesting that a combination of aldynoglia plus alkaline fibrin and Tol-51 compound could be useful as a therapeutic strategy for tSCI repair. Full article

Following spinal cord injury (SCI), the regenerative capacity of the central nervous system (CNS) is severely limited by the failure of axonal regeneration. The regeneration of CNS axons has been shown to occur by grafting predegenerated peripheral nerves (PPNs) and to be promoted by the transplantation of neural precursor cells (NPCs). The introduction of a combinatorial treatment of PPNs and NPCs after SCI has to address the additional problem of glial scar formation, which prevents regenerating axons from leaving the implant and making functional connections. Previously, we discovered that the synthetic sulfoglycolipid Tol-51 inhibits astrogliosis. The objective was to evaluate axonal regeneration and locomotor function improvement after SCI in rats treated with a combination of PPN, NPC, and Tol-51. One month after SCI, the scar tissue was removed and replaced with segments of PPN or PPN+Tol-51; PPN+NPC+Tol-51. The transplantation of a PPN segment favors regenerative axonal growth; in combination with Tol-51 and NPC, 30% of the labeled descending corticospinal axons were able to grow through the PPN and penetrate the caudal spinal cord. The animals treated with PPN showed significantly better motor function. Our data demonstrate that PPN implants plus NPC and Tol-51 allow successful axonal regeneration in the CNS. Full article

Unsuccessful axonal regeneration in transected spinal cord injury (SCI) is mainly attributed to shortage of growth factors, inhibitory glial scar, and low intrinsic regenerating capacity of severely injured neurons. Previously, we constructed an axonal growth permissive pathway in a thoracic hemisected injury by transplantation of Schwann cells overexpressing glial-cell-derived neurotrophic factor (SCs-GDNF) into the lesion gap as well as the caudal cord and proved that this novel permissive bridge promoted the regeneration of descending propriospinal tract (dPST) axons across and beyond the lesion. In the current study, we subjected rats to complete thoracic (T11) spinal cord transections and examined whether these combinatorial treatments can support dPST axons’ regeneration beyond the transected injury. The results indicated that GDNF significantly improved graft–host interface by promoting integration between SCs and astrocytes, especially the migration of reactive astrocyte into SCs-GDNF territory. The glial response in the caudal graft area has been significantly attenuated. The astrocytes inside the grafted area were morphologically characterized by elongated and slim process and bipolar orientation accompanied by dramatically reduced expression of glial fibrillary acidic protein. Tremendous dPST axons have been found to regenerate across the lesion and back to the caudal spinal cord which were otherwise difficult to see in control groups. The caudal synaptic connections were formed, and regenerated axons were remyelinated. The hindlimb locomotor function has been improved. Full article