Selective brain hypothermia-induced neuroprotection against focal cerebral ischemia/reperfusion injury is associated with Fis1 inhibition

Hypothermia improves neuronal network recovery in a human-derived in vitro model of oxygen-deprivation

Mild therapeutic hypothermia showed potential neuroprotective properties during and after cerebral hypoxia or ischemia in experimental animal studies. However, in clinical trials, where hypothermia is mainly applied after reperfusion, results were divergent and neurophysiological effects unclear. In our current study, we employed human-derived neuronal networks to investigate how treatment with hypothermia during hypoxia influences neuronal functionality and whether it improves post-hypoxic recovery. We differentiated neuronal networks from human induced pluripotent stem cells on micro-electrode arrays (MEAs). We studied the effect of hypothermia (34°C)-as well hyperthermia (39°C) - on neuronal functionality during and after hypoxia using MEAs. We also studied the effects on the number of synaptic puncta and cell viability by immunocytochemistry. In comparison to neuronal networks under normothermia, we found that hypothermia during hypoxia improved functional neuronal network recovery, expressed as enhanced neuronal network activity. This was associated with prevention of synaptic loss during and after the hypoxic phase. Furthermore, hypothermia improved cell viability after the hypoxic phase. Instead, hyperthermia during hypoxia had detrimental effects, with an irreversible loss of neuronal network function, loss of synaptic puncta and decreased cell viability. Our results show potential neuroprotective properties of hypothermia occurring during hypoxia, indicating that administering hypothermia to bridge the time to reperfusion may be beneficial in clinical settings.

Expression of NGF, proNGF, p75NTR in lung injury induced by cerebral ischemia-reperfusion in young and elderly rats

OBJECTIVE

This study aims to investigate the expression levels of Nerve Growth Factor (NGF), the precursor form of NGF (proNGF), and p75 neurotrophin receptor (p75NTR) in lung injury induced by cerebral Ischemia-Reperfusion (I/R) in both young and elderly rats.

METHODS

Male Sprague-Dawley rats, categorized as young (3-months-old) and elderly (16-months-old), were divided into four experimental groups: Young Sham, Young I/R, Elderly Sham, and Elderly I/R. Each group underwent either sham surgery or ischemia-reperfusion treatment. Following 24 h post-procedure, the severity of cerebral ischemia was assessed using the Zea Longa 5-point scoring system, and lung tissue pathological changes were examined using Hematoxylin and Eosin (HE) staining. Western blot analysis was utilized to measure the expression levels of NGF, proNGF, and p75NTR proteins in lung tissue.

RESULTS

Both young and elderly I/R groups exhibited lung tissue congestion and edema compared to their respective sham groups, with a significant increase in pathological scores (p < 0.05). Furthermore, the elderly I/R group demonstrated a significantly higher pathological score compared to the young I/R group (p < 0.05). Western blot analysis revealed that compared to the young sham group, the expression of NGF in the lung tissue of elderly sham rats decreased (p < 0.05), while proNGF and p75NTR increased (p < 0.05). Additionally, compared to the sham group, the levels of NGF, proNGF, and p75NTR in lung tissue were elevated in both young and elderly I/R groups of rats (p < 0.05). Moreover, the expression of proNGF and p75NTR in lung tissue was higher in the elderly I/R group than in the young I/R group (p < 0.05).

CONCLUSION

Cerebral ischemia-reperfusion-induced lung injury was associated with increased expression of proNGF and p75NTR, as well as decreased NGF expression in lung tissue. These alterations in NGF, proNGF, and p75NTR may contribute to the susceptibility to age-related lung injury.

Therapeutic potential of microglia-derived extracellular vesicles in ischemic stroke

Ischemic stroke (IS) is a debilitating neurological disorder with limited treatment options. Extracellular vesicles (EVs) have emerged as crucial lipid bilayer particles derived from various cell types that facilitate intercellular communication and enable the exchange of proteins, lipids, and genetic material. Microglia are resident brain cells that play a crucial role in brain development, maintenance of neuronal networks, and injury repair. They secrete numerous extracellular vesicles in different states. Recent evidence indicates that microglia-derived extracellular vesicles (M-EVs) actively participate in mediating various biological processes, such as neuroprotection and neurorepair, in stroke, making them an excellent therapeutic approach for treating this condition. This review comprehensively summarizes the latest research on M-EVs in stroke and explores their potential as novel therapeutic targets for this disorder. Additionally, it provides an overview of the effects and functions of M-EVs on stroke recovery to facilitate the development of clinically relevant therapies for IS.

Neural Stem Cell-Derived Small Extracellular Vesicles: key Players in Ischemic Stroke Therapy - A Comprehensive Literature Review

Ischemic stroke, being a prominent contributor to global disability and mortality, lacks an efficacious therapeutic approach in current clinical settings. Neural stem cells (NSCs) are a type of stem cell that are only found inside the nervous system. These cells can differentiate into various kinds of cells, potentially regenerating or restoring neural networks within areas of the brain that have been destroyed. This review begins by providing an introduction to the existing therapeutic approaches for ischemic stroke, followed by an examination of the promise and limits associated with the utilization of NSCs for the treatment of ischemic stroke. Subsequently, a comprehensive overview was conducted to synthesize the existing literature on the underlying processes of neural stem cell-derived small extracellular vesicles (NSC-sEVs) transplantation therapy in the context of ischemic stroke. These mechanisms encompass neuroprotection, inflammatory response suppression, and endogenous nerve and vascular regeneration facilitation. Nevertheless, the clinical translation of NSC-sEVs is hindered by challenges such as inadequate targeting efficacy and insufficient content loading. In light of these limitations, we have compiled an overview of the advancements in utilizing modified NSC-sEVs for treating ischemic stroke based on current methods of extracellular vesicle modification. In conclusion, examining NSC-sEVs-based therapeutic approaches is anticipated to be prominent in both fundamental and applied investigations about ischemic stroke.

Synergistic action of Hedyotis diffusa Willd and Andrographis paniculata in Nasopharyngeal Carcinoma: Downregulating AKT1 and upregulating VEGFA to curb tumorigenesis

OBJECTIVE

Nasopharyngeal carcinoma (NPC) remains a challenging cancer to treat. This study investigates the molecular mechanisms of Hedyotis diffusa Willd (HDW) combined with Andrographis paniculata (AP) in treating NPC.

METHODS

Key compounds and target genes in HDW and AP were analyzed using network pharmacology. Protein-protein interaction (PPI) networks were constructed with STRING and visualized using Cytoscape. MCODE identified critical clusters, while DAVID facilitated GO and KEGG analyses. In vivo and in vitro experiments evaluated HDW-AP effects on NPC, including tumor volume, weight, Ki-67 expression, cell apoptosis, migration, invasion, cell cycle distribution, and DNA damage.

RESULTS

The database identified 495 NPC-related genes and 26 compounds in the HDW-AP pair, targeting 165 genes. Fifty-eight potential therapeutic genes were found, leading to 18 key targets. KEGG analysis revealed a significant impact on 78 pathways, especially cancer pathways. Both in vivo and in vitro tests showed HDW-AP inhibited NPC cell proliferation, migration, invasion, and induced apoptosis. Mechanistically, this was achieved through AKT1 downregulation and VEGFA upregulation.

CONCLUSION

The combination of HDW and AP targets 16 key genes to impede the development of NPC, primarily by modulating AKT1 and VEGFA pathways.

Emerging Treatment Strategies for Cerebral Ischemia-Reperfusion Injury

Cerebral ischemia-reperfusion injury (CI/RI) injury is a common feature of ischemic stroke which occurs when the blood supply is restored after a period of ischemia in the brain. Reduced blood-flow to the brain during CI/RI compromises neuronal cell health as a result of mitochondrial dysfunction, oxidative stress, cytokine production, inflammation and tissue damage. Reperfusion therapy during CI/RI can restore the blood flow to ischemic regions of brain which are not yet infarcted. The long-term goal of CI/RI therapy is to reduce stroke-related neuronal cell death, disability and mortality. A range of drug and interventional therapies have emerged that can alleviate CI/RI mediated oxidative stress, inflammation and apoptosis in the brain. Herein, we review recent studies on CI/RI interventions for which a mechanism of action has been described and the potential of these therapeutic modalities for future use in the clinic.

Mitochondrial Quality and Quantity Control: Mitophagy Is a Potential Therapeutic Target for Ischemic Stroke

Ischemic stroke is a cerebrovascular disease with high mortality and disability, which seriously affects the health and lives of people around the world. Effective treatment for ischemic stroke has been limited by its complex pathological mechanisms. Increasing evidence has indicated that mitochondrial dysfunction plays an essential role in the occurrence, development, and pathological processes of ischemic stroke. Therefore, strict control of the quality and quantity of mitochondria via mitochondrial fission and fusion as well as mitophagy is beneficial to the survival and normal function maintenance of neurons. Under certain circumstances, excessive mitophagy also could induce cell death. This review discusses the dynamic changes and double-edged roles of mitochondria and related signaling pathways of mitophagy in the pathophysiology of ischemic stroke. Furthermore, we focus on the possibility of modulating mitophagy as a potential therapy for the prevention and prognosis of ischemic stroke. Notably, we reviewed recent advances in the studies of natural compounds, which could modulate mitophagy and exhibit neuroprotective effects, and discussed their potential application in the treatment of ischemic stroke.

Clinical Observation of Salvianolic Acid Combined with Panax Notoginseng Saponins Combined with Basic Nursing Intervention on Cerebral Ischemia-Reperfusion Injury in Rats

Objective

To analyze the clinical observation of salvianolic acid combined with panax notoginseng saponins combined with basic nursing intervention on cerebral ischemia-reperfusion injury in rats and its effects on the expression of apoptosis-related proteins Bcl-2, Bax and caspase-3.

Methods

A total of 72 male Wistar rats were randomly divided into sham, ischemia/reperfusion (I/R), edaravone (Eda), salvianolic acid (SA), panax notoginseng saponins (PNS), and SA+PNS group. After administration for 5 days, the neurological function, cerebral infarction volume, brain index, and brain water content of rats were observed. ELISA kit assay was applied to measure the levels of IL-1β, IL-6, IL-8, TNF-α, MDA, SOD, GSH-Px, and T-AOC activity. Western blotting assay was used to detect the protein levels of p-53, NF-κB, Bcl-2, Bax, and Caspase-3 in the brain tissues surrounding infarction lesion.

Results

Compared with sham group, the mNSS score, brain index, brain water content, infarction volumes, MDA activity, and the levels of IL-6, IL-8, TNF-α and IL-1β as well as the protein levels of p-53, NF-κB, Bax and Caspase-3 were significantly increased, while the levels of Bcl-2 protein, SOD, GSH-Px and T-AOC were significantly decreased in I/R group. However, these levels were reversed in SA group, PNS group and SA + PNS group. Moreover, these changes in SA + PNS group were more obvious than those in SA and PNS group, and the differences were statistically significant.

Conclusions

SA, PNS and they combined with basic nursing have protective effects on cerebral I/R injury, and the combination with basic nursing has better effects than that used alone. The mechanism may be to regulate the expression of downstream apoptotic proteins by inhibiting the TLR4/NF-κB signaling pathway, thereby reducing neurological damage in rats.

Cellular and Molecular Targets for Non-Invasive, Non-Pharmacological Therapeutic/Rehabilitative Interventions in Acute Ischemic Stroke

BACKGROUND

Cerebral circulation delivers the blood flow to the brain through a dedicated network of sanguine vessels. A healthy human brain can regulate cerebral blood flow (CBF) according to any physiological or pathological challenges. The brain is protected by its self-regulatory mechanisms, which are dependent on neuronal and support cellular populations, including endothelial ones, as well as metabolic, and even myogenic factors.

OBJECTIVES

Accumulating data suggest that "non-pharmacological" approaches might provide new opportunities for stroke therapy, such as electro-/acupuncture, hyperbaric oxygen therapy, hypothermia/cooling, photobiomodulation, therapeutic gases, transcranial direct current stimulations, or transcranial magnetic stimulations. We reviewed the recent data on the mechanisms and clinical implications of these non-pharmaceutical treatments.

METHODS

To present the state-of-the-art for currently available non-invasive, non-pharmacological-related interventions in acute ischemic stroke, we accomplished this synthetic and systematic literature review based on the Preferred Reporting Items for Systematic Principles Reviews and Meta-Analyses (PRISMA).

RESULTS

The initial number of obtained articles was 313. After fulfilling the five steps in the filtering/selection methodology, 54 fully eligible papers were selected for synthetic review. We enhanced our documentation with other bibliographic resources connected to our subject, identified in the literature within a non-standardized search, to fill the knowledge gaps. Fifteen clinical trials were also identified.

DISCUSSION

Non-invasive, non-pharmacological therapeutic/rehabilitative interventions for acute ischemic stroke are mainly holistic therapies. Therefore, most of them are not yet routinely used in clinical practice, despite some possible beneficial effects, which have yet to be supplementarily proven in more related studies. Moreover, few of the identified clinical trials are already completed and most do not have final results.

CONCLUSIONS

This review synthesizes the current findings on acute ischemic stroke therapeutic/rehabilitative interventions, described as non-invasive and non-pharmacological.

Hypothermia selectively protects the anterior forebrain mesocircuit during global cerebral ischemia

Hypothermia is an important protective strategy against global cerebral ischemia following cardiac arrest. However, the mechanisms of hypothermia underlying the changes in different regions and connections of the brain have not been fully elucidated. This study aims to identify the metabolic nodes and connection integrity of specific brain regions in rats with global cerebral ischemia that are most affected by hypothermia treatment. ¹⁸F-fluorodeoxyglucose positron emission tomography was used to quantitatively determine glucose metabolism in different brain regions in a rat model of global cerebral ischemia established at 31–33°C. Diffusion tensor imaging was also used to reconstruct and explore the brain connections involved. The results showed that, compared with the model rats established at 37–37.5°C, the rat models of global cerebral ischemia established at 31–33°C had smaller hypometabolic regions in the thalamus and primary sensory areas and sustained no obvious thalamic injury. Hypothermia selectively preserved the integrity of the anterior forebrain mesocircuit, exhibiting protective effects on the brain during the global cerebral ischemia. The study was approved by the Institutional Animal Care and Use Committee at Capital Medical University (approval No. XW-AD318-97-019) on December 15, 2019.

DAKS1, a Kunitz Scaffold Peptide from the Venom Gland of Deinagkistrodon acutus Prevents Carotid-Artery and Middle-Cerebral-Artery Thrombosis via Targeting Factor XIa

Scaffold-based peptides (SBPs) are fragments of large proteins that are characterized by potent bioactivity, high thermostability, and low immunogenicity. Some SBPs have been approved by the FDA for human use. In the present study, we developed SBPs from the venom gland of Deinagkistrodon acutus (D. acutus) by combining transcriptome sequencing and Pfam annotation. To that end, 10 Kunitz peptides were discovered from the venom gland of D. acutus, and most of which peptides exhibited Factor XIa (FXIa) inhibitory activity. One of those, DAKS1, exhibiting strongest inhibitory activity against FXIa, was further evaluated for its anticoagulant and antithrombotic activity. DAKS1 prolonged twofold APTT at a concentration of 15 μM in vitro. DAKS1 potently inhibited thrombosis in a ferric chloride-induced carotid-artery injury model in mice at a dose of 1.3 mg/kg. Furthermore, DAKS1 prevented stroke in a transient middle cerebral-artery occlusion (tMCAO) model in mice at a dose of 2.6 mg/kg. Additionally, DAKS1 did not show significant bleeding risk at a dose of 6.5 mg/kg. Together, our results indicated that DAKS1 is a promising candidate for drug development for the treatment of thrombosis and stroke disorders.

Tetrandrine attenuates ischemia/reperfusion‑induced neuronal damage in the subacute phase

Ischemic stroke, the third leading cause of disability globally, imposes a notable economic burden. Tetrandrine (Tet), which has been widely used clinically, exhibits potential protective effects against stroke. However, there has been little pre‑clinical research to evaluate the therapeutic effects of Tet on stroke. The present study investigated the beneficial effect of Tet on ischemia‑reperfusion (I/R) injury and its underlying mechanism in rats. Rats were subjected to occlusion of the middle cerebral artery, then treated with Tet (30 mg/kg/day, intraperitoneal) in the subacute phase for 7 days. In order to detect the effects of Tet on the behavior of rats, modified neurological severity score and longa behavior, grasping capability and inclined plane tests were conducted on days 1, 3 and 7 following cerebral ischemia. In addition, neuronal apoptosis in the cortex and hippocampus following ischemia was assessed by Nissl staining and TUNEL assay. Finally, oxidative stress was evaluated by measurement of free radicals and immunofluorescence staining of LC3 was used to assess autophagy. Tet improved neurological function and decreased infarct volume in I/R injury rats. Tet also prevented neuronal apoptosis in the cortex and hippocampus region. In addition, Tet protected against oxidative damage following ischemia, which was reflected by decreased levels of nitric oxide and malondialdehyde and increased levels of glutathione (GSH) and GSH peroxidase. In addition, the expression levels of the autophagy marker LC3 decreased in the Tet treatment group. In conclusion, Tet attenuated I/R‑induced neuronal damage in the subacute phase by decreasing oxidative stress, apoptosis and autophagy.

Selective-cerebral-hypothermia-induced neuroprotection against-focal cerebral ischemia/reperfusion injury is associated with an increase in SUMO2/3 conjugation

Selective cerebral hypothermia is considered an effective treatment for neuronal injury after stroke and avoids the complications of general hypothermia. Several recent studies hanve suggested that SUMO2/3 conjugation occurs following cerebral ischemia/reperfusion (I/R) injury. However, the relationship between the cerebral protective effect of selective cerebral hypothermia and SUMO2/3 conjugation remains unclear. In this study, we investigated the effect of selective cerebral hypothermia on SUMO2/3 conjugation during focal cerebral I/R injury. A total of 140 Sprague-Dawley rats were divided into four groups. In the sham group, only the carotid artery was exposed. The endoluminal filament technique was used to induce middle cerebral artery occlusion in the other three groups. After 2 h of occlusion, the filaments were slowly removed to allow blood reperfusion in the I/R group. In the hypothermia (HT) group and normothermia (NT) group, normal saline at 4 °C and 37 °C, respectively , was perfused through the carotid artery, followed by the restoration of blood flow. The results of the modified neurological severity score (mNSS), 2,3,5-triphenyltetrazolium chloride (TTC) staining, hematoxylin-eosin (HE) staining, and terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) staining demonstrated that selective cerebral hypothermia significantly decreased I/R-induced neuronal injury (mNSS, n = 8, 24 h, HT (5.88 ± 2.36) vs. I/R (8.63 ± 3.38), P < 0.05. 48 h, HT (5.75 ± 2.25) vs. I/R (8.5 ± 2.88), P < 0.05. Cerebral infarct volume percentages, n = 5, HT (18.71 ± 2.13) vs. I/R (41.52 ± 2.90), P < 0.01. Cell apoptosis rate, n = 5, 24 h, HT (21.28 ± 2.61) vs. I/R (43.72 ± 4.30), P < 0.05. 48 h, HT (20.50 ± 2.53) vs. I/R (38.94 ± 2.93), P < 0.05). The expression of Ubc9 and conjugated SUMO2/3 proteins was increased at 24 and 48 h after reperfusion in the 3 non-sham groups, and hypothermia further upregulated the expression of Ubc9 and conjugated SUMO2/3 proteins in the HT group. The expression of SENP3 was increased in the NT group and I/R group, while it was decreased in the HT group at 24 and 48 h after reperfusion (Relative quantities, n = 5, Ubc9, 24 h, HT (2.44 ± 0.22) vs. I/R (1.55 ± 0.39), P < 0.05. 48 h, HT (2.69 ± 0.16) vs. I/R (2.25 ± 0.33), P < 0.05. SENP3, 24 h, HT (0.47 ± 0.15) vs. I/R (2.18 ± 0.43), P < 0.05. 48 h, HT (0.72 ± 0.06) vs. I/R (1.51 ± 0.19), P < 0.05. conjugated SUMO2/3 proteins, 24 h, HT (2.84 ± 0.24) vs. I/R (2.51 ± 0.20), P < 0.05. 48 h, HT (2.73 ± 0.13) vs. I/R (2.44 ± 0.13), P < 0.05). Further analysis showed that the variation in SENP3 expression was more obvious than that in Ubc9 under hypothermia intervention in the HT group. These findings suggest that selective cerebral hypothermia could increase SUMO2/3 modification mainly via down-regulating the expression of SENP3, and then exert neuroprotective effects in rats with cerebral I/R injury.

MicroRNA-670 aggravates cerebral ischemia/reperfusion injury via the Yap pathway

Apoptosis is an important programmed cell death process involved in ischemia/reperfusion injury. MicroRNAs are considered to play an important role in the molecular mechanism underlying the regulation of cerebral ischemia and reperfusion injury. However, whether miR-670 can regulate cell growth and death in cerebral ischemia/reperfusion and the underlying mechanism are poorly understood. In this study, we established mouse models of transient middle artery occlusion and Neuro 2a cell models of oxygen-glucose deprivation and reoxygenation to investigate the potential molecular mechanism by which miR-670 exhibits its effects during cerebral ischemia/reperfusion injury both in vitro and in vivo. Our results showed that after ischemia/reperfusion injury, miR-670 expression was obviously increased. After miR-670 expression was inhibited with an miR-670 antagomir, cerebral ischemia/reperfusion injury-induced neuronal death was obviously reduced. When miR-670 overexpression was induced by an miR-670 agomir, neuronal apoptosis was increased. In addition, we also found that miR-670 could promote Yap degradation via phosphorylation and worsen neuronal apoptosis and neurological deficits. Inhibition of miR-670 reduced neurological impairments after cerebral ischemia/reperfusion injury. These results suggest that microRNA-670 aggravates cerebral ischemia/reperfusion injury through the Yap pathway, which may be a potential target for treatment of cerebral ischemia/reperfusion injury. The present study was approved by the Institutional Animal Care and Use Committee of China Medical University on February 27, 2017 (IRB No. 2017PS035K).

The Role of Mitophagy in Ischemic Stroke

Mitochondria are important places for eukaryotes to carry out energy metabolism and participate in the processes of cell differentiation, cell information transmission, and cell apoptosis. Autophagy is a programmed intracellular degradation process. Mitophagy, as a selective autophagy, is an evolutionarily conserved cellular process to eliminate dysfunctional or redundant mitochondria, thereby fine-tuning the number of mitochondria and maintaining energy metabolism. Many stimuli could activate mitophagy to regulate related physiological processes, which could ultimately reduce or aggravate the damage caused by stimulation. Stroke is a common disease that seriously affects the health and lives of people around the world, and ischemic stroke, which is caused by cerebral vascular stenosis or obstruction, accounts for the vast majority of stroke. Abnormal mitophagy is closely related to the occurrence, development and pathological mechanism of ischemic stroke. However, the exact mechanism of mitophagy involved in ischemic stroke has not been fully elucidated. In this review, we discuss the process and signal pathways of mitophagy, the potential role of mitophagy in ischemic stroke and the possible signal transduction pathways. It will help deepen the understanding of mitophagy and provide new ideas for the treatment of ischemic stroke.