Ischemic Stroke, Lessons from the Past towards Effective Preclinical Models

Effects of stem cell therapy on preclinical stroke

Stroke, particularly ischemic stroke, is a leading cause of global mortality and disability. It is caused by blood flow obstruction and reduced oxygen delivery to brain tissue. Conventional treatments, such as tissue plasminogen activator (tPA) and mechanical thrombectomy (MT), have limited efficacy in repairing neural damage and carry risks of adverse effects. As a result, stem cell therapies, including mesenchymal stem cells (MSCs), have emerged as promising approaches for enhancing neural recovery and offering neuroprotection in ischemic stroke management. MSCs offer multifaceted benefits, such as reducing inflammation, protecting neurons, and promoting angiogenesis and neurogenesis. Recent evidence highlights the importance of MSC secretomes-extracellular vesicles (EVs) and exosomes rich in neuroprotective factors, such as microRNAs, proteins, and cytokines. These bioactive molecules demonstrated considerable efficacy in preclinical models by reducing neuroinflammation, preserving neurovascular integrity, and promoting cellular repair in ischemic environments. Preclinical in vitro and in vivo studies demonstrate the potential of the MSC secretomes to restore brain function after ischemic stroke. This is achieved by enhancing neuronal survival through mechanisms such as angiogenesis or vascular recovery, neuroprotection including modulation of immune or inflammatory responses, apoptosis, and autophagy, and promoting post-stroke neurogenesis. This review explores the translational challenges and future potential of integrating conventional ischemic stroke therapies with stem cell-based or cell-free approaches. The present study synthesizes current insights into the role of MSC-derived secretomes from both in vitro and in vivo studies.

Methodological Approaches to Experimental Evaluation of Neuroprotective Action of Potential Drugs

The authors propose a novel approach to a comprehensive evaluation of neuroprotective effects using both in vitro and in vivo methods. This approach allows for the initial screening of numerous newly synthesized chemical compounds and substances from plant and animal sources while saving animal life by reducing the number of animals used in research. In vitro techniques, including mitochondrial suspensions and neuronal cell cultures, enable the assessment of neuroprotective activity, which can be challenging in intact organisms. The preliminary methods help outline the neuroprotection mechanism depending on the neurodestruction agent. The authors have validated a model of acute cerebrovascular accident, which simulates key cerebrovascular phenomena such as reduced cerebral blood flow, energy deficit, glutamate-calcium excitotoxicity, oxidative stress, and early gene expression. A significant advantage of this model is its ability to reproduce the clinical picture of cerebral ischemia: impaired motor activity; signs of neurological deficits (paresis, paralysis, etc.); as well as disturbances in attention, learning, and memory. Crucial to this approach is the selection of biochemical, molecular, and cellular markers to evaluate nerve tissue damage and characterize potential neuroprotective agents. Additionally, a comprehensive set of molecular, biochemical, histological, and immunohistochemical methods is proposed for evaluating neuroprotective effects and underlying mechanisms of potential pharmaceutical compounds.

Organoids Modeling Stroke in a Petri Dish

Stroke is a common neurological disorder, the second leading cause of death, and the third leading cause of disability. Unfortunately, the only approved drug for it is tissue plasminogen, but the therapeutic window is limited. In this context, preclinical studies are relevant to better dissect the underlying mechanisms of stroke and for the drug screening of potential therapies. Brain organoids could be relevant in this setting. They are derived from pluripotent stem cells or isolated organ progenitors that differentiate to form an organ-like tissue, exhibiting multiple cell types that self-organize to form a structure not unlike the organ in vivo. Brain organoids mimic many key features of early human brain development at molecular, cellular, structural, and functional levels and have emerged as novel model systems that can be used to investigate human brain diseases including stroke. Brain organoids are a promising and powerful tool for ischemic stroke studies; however, there are a few concerns that need to be addressed, including the lack of vascularization and the many cell types that are typically present in the human brain. The aim of this review is to discuss the potential of brain organoids as a novel model system for studying ischemic stroke, highlighting both the advantages and disadvantages in the use of this technology.

Are Ischemic Stroke and Alzheimer's Disease Genetically Consecutive Pathologies?

Complex diseases that affect the functioning of the central nervous system pose a major problem for modern society. Among these, ischemic stroke (IS) holds a special place as one of the most common causes of disability and mortality worldwide. Furthermore, Alzheimer's disease (AD) ranks first among neurodegenerative diseases, drastically reducing brain activity and overall life quality and duration. Recent studies have shown that AD and IS share several common risk and pathogenic factors, such as an overlapping genomic architecture and molecular signature. In this review, we will summarize the genomics and RNA biology studies of IS and AD, discussing the interconnected nature of these pathologies. Additionally, we highlight specific genomic points and RNA molecules that can serve as potential tools in predicting the risks of diseases and developing effective therapies in the future.

Identification of brain endothelial cell-specific genes and pathways in ischemic stroke by integrated bioinformatical analysis

BACKGROUND

Ischemic stroke (IS) is a life-threatening condition with limited treatment options; thus, finding the potential key genes for novel therapeutic targets is urgently needed. This study aimed to explore novel candidate genes and pathways of brain microvessel endothelial cells (ECs) in IS by bioinformatics analysis.

MATERIALS AND METHODS

The gene expression profiles of brain tissues or brain ECs in IS mice were downloaded from the online gene expression omnibus (GEO) to obtain the differentially expressed genes (DEGs) by R software. Functional enrichment analyses were used to cluster the functions and signaling pathways of the DEGs, while DEG-associated protein-protein interaction network was performed to identify hub genes. The target microRNAs and competitive endogenous RNA networks of key hub genes were constructed by Cytoscape.

RESULTS

Totally 84 DEGs were obtained from 6 brain tissue samples and 4 brain vascular EC samples both from IS mice in the datasets GSE74052 and GSE137482, with significant enrichment in immune responses, such as immune system processes and T-cell activation. Eight hub genes filtered by Cytoscape were validated by two other GEO datasets, wherein key genes of interest were verified by reverse transcription-polymerase chain reaction using an in vitro ischemic model of EC cultures. Our data indicated that AURKA and CENPF might be potential therapeutic target genes for IS, and Malat1/Snhg12/Xist-miR-297b-3p-CENPF, as well as Mir17 hg-miR-34b-3p-CENPF, might be RNA regulatory pathways to control IS progression.

CONCLUSIONS

Our work identified two brain EC-specific expressed genes in IS, namely, AURKA and CENPF, as potential gene targets for IS treatment. In addition, we presented miR-297b-3p/miR-34b-3p-CENPF as the potential RNA regulatory axes to prevent pathogenesis of IS.

Therapeutic Effect of Rapamycin on TDP-43-Related Pathogenesis in Ischemic Stroke

Stroke is a major cause of death and disability across the world, and its detrimental impact should not be underestimated. Therapies are available and effective for ischemic stroke (e.g., thrombolytic recanalization and mechanical thrombectomy); however, there are limitations to therapeutic interventions. Recanalization therapy has developed dramatically, while the use of adjunct neuroprotective agents as complementary therapies remains deficient. Pathological TAR DNA-binding protein (TDP-43) has been identified as a major component of insoluble aggregates in numerous neurodegenerative pathologies, including ALS, FTLD and Alzheimer's disease. Here, we show that increased pathological TDP-43 fractions accompanied by impaired mitochondrial function and increased gliosis were observed in an ischemic stroke rat model, suggesting a pathological role of TDP-43 in ischemic stroke. In ischemic rats administered rapamycin, the insoluble TDP-43 fraction was significantly decreased in the ischemic cortex region, accompanied by a recovery of mitochondrial function, the attenuation of cellular apoptosis, a reduction in infarct areas and improvements in motor defects. Accordingly, our results suggest that rapamycin provides neuroprotective benefits not only by ameliorating pathological TDP-43 levels, but also by reversing mitochondrial function and attenuating cell apoptosis in ischemic stroke.