Recovery After Stroke: New Insight to Promote Brain Plasticity.
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ABSTRACT:
SUBMITTER: Otero-Ortega L
PROVIDER: S-EPMC8639681 | biostudies-literature | 2021
REPOSITORIES: biostudies-literature
Publications
Recovery After Stroke: New Insight to Promote Brain Plasticity.
Otero-Ortega Laura L Gutiérrez-Fernández María M Díez-Tejedor Exuperio E
Frontiers in neurology 20211119
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Project description:Stroke disturbs both the structural and functional integrity of the brain. The understanding of stroke pathophysiology has improved greatly in the past several decades. However, effective therapy is still limited, especially for patients who are in the subacute or chronic phase. Multiple novel therapies have been developed to improve clinical outcomes by improving brain plasticity. These approaches either focus on improving brain remodeling and restoration or on constructing a neural bypass to avoid brain injury. This review describes emerging therapies, including modern rehabilitation, brain stimulation, cell therapy, brain-computer interfaces, and peripheral nervous transfer, and highlights treatment-induced plasticity. Key evidence from basic studies on the underlying mechanisms is also briefly discussed. These insights should lead to a deeper understanding of the overall neural circuit changes, the clinical relevance of these changes in stroke, and stroke treatment progress, which will assist in the development of future approaches to enhance brain function after stroke.
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Project description:Astrocytes are important glia cell type in the central nervous system. These cells can undergo transformation to a reactive state upon injury such as focal ischemic stroke (FIS). Reactive astrocytes are distinct from normal or homeostatic astrocytes in morphology, protein profiles and metabolic functions. Glial cell-derived neurotrophic factor (GDNF) was discovered as a potent survival neurotrophic factor for multiple subtypes of neurons and can be released from reactive astrocytes. In our previous study, we found that GDNF expression was upregulated in reactive astrocytes following ischemic stroke. Specific knock out of GDNF in reactive astrocytes exacerbated brain damage and motor deficits after ischemic stroke. Here, using in vitro and in vivo ischemia models, we investigated the effects of GDNF overexpression in astrocytes on neuronal survival and brain recovery after ischemia. We observed that astrocyte specific GDNF overexpression by viral transduction could decrease brain infarction and promote motor function recovery after photothrombosis (PT)-induced FIS. In addition, GDNF overexpression in astrocytes could increase the proliferation of reactive astrocytes and reduce oxidative stress after PT. Using the oxygen-glucose deprivation (OGD) model of cultured astrocytes, we confirmed that this ischemic insult could upregulate GDNF expression and increase its release to extracellular space. Transfection of GDNF DNA plasmid could further increase GDNF release after OGD. To further study the effects of reactive astrocytes-derived extracellular GDNF on neuronal survival after ischemia, cultured neurons subjected to OGD were exposed to astrocyte conditioned medium (ACM). The ACM collected from OGD subjected astrocyte culture could significantly reduce neuronal death, while neutralizing antibodies against GDNF and its receptors including GFRα1, RET and p-RET could suppress this beneficial effect. We also found that reactive astrocytes-derived GDNF could trigger the activation of RET receptors in cultured neurons and suppress neuronal mitochondrial fission and caspase-dependent cell apoptosis after OGD. Overall, our results indicate that reactive astrocytes-derived GDNF could play an important role in neuronal survival and functional recovery and underscore the non-cell autonomy underlying astrocyte-neuron interactions in brain repair after ischemic stroke.
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Project description:IPSC-NPC were transplanted in a mouse model of stroke. To dissect the molecular graft composition and identify graft-host interactions, single nucleus profiling of the cell transplants and host stroke tissue was performed. We identified graft differentiation preferentially towards GABAergic cells with remaining cells acquiring glutamatergic neuron, astrocyte, and NPC-like phenotypes. Interaction between graft and host transcriptome indicated that GABAergic cell grafts were primarily involved in graft-host communication through the regeneration-associated NRXN, NRG, NCAM and SLIT signalling pathways
2025-08-06 | GSE259430 | GEO
Project description:Emerging evidence suggests that tissue plasminogen activator (tPA), currently the only FDA-approved medication for ischemic stroke, exerts important biological actions on the CNS besides its well-known thrombolytic effect. In this study, we investigated the role of tPA on primary neurons in culture and on brain recovery and plasticity after ischemic stroke in mice. Treatment with recombinant tPA stimulated axonal growth in culture, an effect independent of its protease activity and achieved through epidermal growth factor receptor (EGFR) signaling. After permanent focal cerebral ischemia, tPA knockout mice developed more severe sensorimotor and cognitive deficits and greater axonal and myelin injury than wild-type mice, suggesting that endogenously expressed tPA promotes long-term neurological recovery after stroke. In tPA knockout mice, intranasal administration of recombinant tPA protein 6 hours poststroke and 7 more times at 2 d intervals mitigated white matter injury, improved axonal conduction, and enhanced neurological recovery. Consistent with the proaxonal growth effects observed in vitro, exogenous tPA delivery increased poststroke axonal sprouting of corticobulbar and corticospinal tracts, which might have contributed to restoration of neurological functions. Notably, recombinant mutant tPA-S478A lacking protease activity (but retaining the EGF-like domain) was as effective as wild-type tPA in rescuing neurological functions in tPA knockout stroke mice. These findings demonstrate that tPA improves long-term functional outcomes in a clinically relevant stroke model, likely by promoting brain plasticity through EGFR signaling. Therefore, treatment with the protease-dead recombinant tPA-S478A holds particular promise as a neurorestorative therapy, as the risk for triggering intracranial hemorrhage is eliminated and tPA-S478A can be delivered intranasally hours after stroke.
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Project description:Treatments that stimulate neuronal excitability enhance motor performance after stroke.cAMP-response-element binding protein (CREB) is a transcription factor that plays a key rolein neuronal excitability. Increasing the levels of CREB with a viral vector in a small pool ofmotor neurons enhances motor recovery after stroke, while blocking CREB signaling preventsstroke recovery. Silencing CREB-transfected neurons in the peri-infarct region with thehM4di-DREADD blocks motor recovery. Reversing this inhibition allows recovery to continue,demonstrating that it is possible to turn off and on stroke recovery by manipulating theactivity of CREB-transfected neurons. CREB transfection enhances re-mapping of injuredsomatosensory and motor circuits, and induces the formation of new connections withinthese circuits. CREB is a central molecular node in the circuit responses after stroke that leadto recovery from motor deficits.
2018-06-08 | GSE115527 | GEO
Project description:Stroke, whether hemorrhagic or ischemic in nature, has the ability to lead to devastating and debilitating patient outcomes, which not only has direct implications from a healthcare standpoint, but its effects are longstanding and they impact the community as a whole. For decades, the goal of advancement and refinement in imaging modalities has been to develop the most precise, convenient, widely available and reproducible interpretable modality for the detection of stroke, not only in its hyperacute phase, but a method to be able to predict its evolution through the natural course of disease. Diagnosis is one of the most important initial roles, which imaging fulfills after the identification of existent pathology. However, imaging fulfills an even more important goal by using a combination of imaging modalities and their precise interpretation, which lends itself to understanding the mechanisms and pathophysiology of underlying disease, and therefore guides therapeutic decision-making in a patient-tailored fashion. This review explores the most commonly used brain imaging modalities, computer tomography, and magnetic resonance imaging, with an aim to demonstrate their dynamic use in uncovering stroke mechanism, facilitating prognostication, and potentially guiding therapy.
| S-EPMC3144982 | biostudies-literature
Project description:An improved understanding of the neuroplastic potential of the brain has allowed advancements in neuromodulatory treatments for acute stroke patients. However, there remains a poor understanding of individual differences in treatment-induced recovery. Individualized information on connectivity disturbances may help predict differences in treatment response and recovery phenotypes. We studied the medical data of 22 ischemic stroke patients who received MRI scans and started repetitive transcranial magnetic stimulation (rTMS) treatment on the same day. The functional and motor outcomes were assessed at admission day, 1 day after treatment, 30 days after treatment, and 90 days after treatment using four validated standardized stroke outcome scales. Each patient underwent detailed baseline connectivity analyses to identify structural and functional connectivity disturbances. An unsupervised machine learning (ML) agglomerative hierarchical clustering method was utilized to group patients according to outcomes at four-time points to identify individual phenotypes in recovery trajectory. Differences in connectivity features were examined between individual clusters. Patients were a median age of 64, 50% female, and had a median hospital length of stay of 9.5 days. A significant improvement between all time points was demonstrated post treatment in three of four validated stroke scales utilized. ML-based analyses identified distinct clusters representing unique patient trajectories for each scale. Quantitative differences were found to exist in structural and functional connectivity analyses of the motor network and subcortical structures between individual clusters which could explain these unique trajectories on the Barthel Index (BI) scale but not on other stroke scales. This study demonstrates for the first time the feasibility of using individualized connectivity analyses in differentiating unique phenotypes in rTMS treatment responses and recovery. This personalized connectomic approach may be utilized in the future to better understand patient recovery trajectories with neuromodulatory treatment.
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Project description:Stroke causes devastating sensory-motor deficits and long-term disability due to disruption of descending motor pathways. Restoration of these functions enables independent living and therefore represents a high priority for those afflicted by stroke. Here, we report that daily administration of gabapentin, a clinically approved drug already used to treat various neurological disorders, promotes structural and functional plasticity of the corticospinal pathway after photothrombotic cortical stroke in adult mice. We found that gabapentin administration had no effects on vascular occlusion, haemodynamic changes nor survival of corticospinal neurons within the ipsilateral sensory-motor cortex in the acute stages of stroke. Instead, using a combination of tract tracing, electrical stimulation and functional connectivity mapping, we demonstrated that corticospinal axons originating from the contralateral side of the brain in mice administered gabapentin extend numerous collaterals, form new synaptic contacts and better integrate within spinal circuits that control forelimb muscles. Not only does gabapentin daily administration promote neuroplasticity, but it also dampens maladaptive plasticity by reducing the excitability of spinal motor circuitry. In turn, mice administered gabapentin starting 1 h or 1 day after stroke recovered skilled upper extremity function. Functional recovery persists even after stopping the treatment at 6 weeks following a stroke. Finally, chemogenetic silencing of cortical projections originating from the contralateral side of the brain transiently abrogated recovery in mice administered gabapentin, further supporting the conclusion that gabapentin-dependent reorganization of spared cortical pathways drives functional recovery after stroke. These observations highlight the strong potential for repurposing gabapentinoids as a promising treatment strategy for stroke repair.
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Project description:Treatments that stimulate neuronal excitability enhance motor performance after stroke. cAMP-response-element binding protein (CREB) is a transcription factor that plays a key role in neuronal excitability. Increasing the levels of CREB with a viral vector in a small pool of motor neurons enhances motor recovery after stroke, while blocking CREB signaling prevents stroke recovery. Silencing CREB-transfected neurons in the peri-infarct region with the hM4Di-DREADD blocks motor recovery. Reversing this inhibition allows recovery to continue, demonstrating that by manipulating the activity of CREB-transfected neurons it is possible to turn off and on stroke recovery. CREB transfection enhances remapping of injured somatosensory and motor circuits, and induces the formation of new connections within these circuits. CREB is a central molecular node in the circuit responses after stroke that lead to recovery from motor deficits.
| S-EPMC5993731 | biostudies-literature
Project description:AimsWe previously showed that the protective effects of endothelial progenitor cells (EPCs)-released exosomes (EPC-EXs) on endothelium in diabetes. However, whether EPC-EXs are protective in diabetic ischemic stroke is unknown. Here, we investigated the effects of EPC-EXs on diabetic stroke mice and tested whether miR-126 enriched EPC-EXs (EPC-EXsmiR126 ) have enhanced efficacy.MethodsThe db/db mice subjected to ischemic stroke were intravenously administrated with EPC-EXs 2 hours after ischemic stroke. The infarct volume, cerebral microvascular density (MVD), cerebral blood flow (CBF), neurological function, angiogenesis and neurogenesis, and levels of cleaved caspase-3, miR-126, and VEGFR2 were measured on day 2 and 14.ResultsWe found that (a) injected EPC-EXs merged with brain endothelial cells, neurons, astrocytes, and microglia in the peri-infarct area; (b) EPC-EXsmiR126 were more effective than EPC-EXs in decreasing infarct size and increasing CBF and MVD, and in promoting angiogenesis and neurogenesis as well as neurological functional recovery; (c) These effects were accompanied with downregulated cleaved caspase-3 on day 2 and vascular endothelial growth factor receptor 2 (VEGFR2) upregulation till day 14.ConclusionOur results indicate that enrichment of miR126 enhanced the therapeutic efficacy of EPC-EXs on diabetic ischemic stroke by attenuating acute injury and promoting neurological function recovery.
| S-EPMC7702230 | biostudies-literature