Mechanisms of ischemic brain damage

Mediation effect of stroke recurrence in the association between post-stroke lactate dehydrogenase and functional disability

Background

We aimed to use lactate dehydrogenase (LDH) as a marker of inflammation burden and quantify post-stroke inflammation's direct and indirect effect on functional disability.

Methods

We analyzed 5,129 patients with acute ischemic stroke (AIS) admitted to Shenyang First People's Hospital. Stroke recurrence and functional outcome measured by the modified Rankin Scale (mRS) were assessed at 90 days. Functional disability was defined as mRS score > 2. Receiver operating characteristic curve and restricted cubic spline (RCS) analysis were conducted to illustrate the associations between LDH levels and 90-day functional outcomes in patients with AIS. Mediation analyses were performed to examine the potential causal chain in which stroke recurrence may mediate the relationship between LDH and functional outcome. Positive correlation between LDH and hs-CRP was found and mediation effects of stroke recurrence in the association between LDH or hs-CRP and functional disability were both less than 20%. Sensitivity analyses in different subgroups showed comparable results.

Results

Among 5,129 included AIS patients, the median (IQR) level of LDH was 186 (161-204.4) U/L. Functional disability was seen in 1200 (23.4%) patients and recurrence was observed in 371(7.2%) patients at 90-day follow-up. Each standard deviation increase in the concentration of LDH was linked to an increased risk of functional disability (adjusted odds ratio[aOR], 1.07; 95%CI,1.04-1.09) and stroke recurrence (aOR,1.02; 95%CI, 1.01-1.04) within 90 days. The highest quartile of LDH (>204.2 U/L) had an elevated risk of suffering functional disability (aOR, 1.21; 95%CI, 1.00-1.47) and recurrence (aOR, 1.21; 95%CI,1.00-1.47) compared with the lowest quartile of LDH (<161 U/L). Stroke recurrence during follow-up explained 12.90% (95%CI, 6.22-21.16%) of the relationship between LDH and functional disability. Positive correlation between LDH and hs-CRP was found and mediation effects of recurrence in the association between LDH or hs-CRP and functional disability were both less than 20%. Sensitivity analyses in different subgroups showed comparable results.

Conclusion

The relationship between LDH and functional disability at 90 days among AIS patients is partially mediated by stroke recurrence, accounting for less than 20%. LDH deserves equal attention as hs-CRP in predicting recurrence and functional outcome. In addition to traditional secondary prevention measures, innovative anti-inflammatory strategies warrant further investigation.

Epidemiology, Pathophysiology, and Current Treatment Strategies in Stroke

Both ischemic and hemorrhagic strokes are critical health issues and the incidence is on the rise. The rapid neurological degeneration that can occur with either type of stroke warrants prompt medical attention. In the article, we critically reviewed the literature examining their incidence, pathophysiology, and present treatment strategies. Clinical trials show conflicting findings, with ischemic strokes accounting for 87% of all strokes. Brain injury following an ischemic stroke results in cell death and necrosis, immune cells being the primary actors in the process of neuroinflammation. In order to develop neuroprotective drugs against ischemic stroke, detailed investigation of glutamate production and metabolism as well as downstream pathways controlled by glutamate receptors provides significant information on the underlying mechanisms. The permeability of the blood-brain barrier and the degradation of glutamine synthase are two potential mechanisms by which peritoneal dialysis accelerates brain-to-blood glutamate clearance and thus reduces glutamate levels in the brain after a stroke. Oxidative stress in an ischemic stroke disturbs the oxidant-antioxidant balance, which is particularly problematic for brain cells that are high in polyunsaturated fatty acids. Because of demographic factors like age, sex, race/ethnicity, and socioeconomic status, the incidence and prevalence of stroke differ across people and regions. For rapid diagnosis and treatment decisions, diagnostic imaging tools such as vascular imaging, CT, and MRI are essential. To aid in the recovery and lessen neurological impairments following a stroke, novel avenues of research are under investigation on neuroprotective medications that target inflammation, oxidative stress, and neuronal death.

Discovering novel plasma biomarkers for ischemic stroke: Lipidomic and metabolomic analyses in an aged mouse model

Ischemic stroke remains a leading cause of mortality and long-term disability worldwide, necessitating efforts to identify biomarkers for diagnosis, prognosis, and treatment monitoring. The present study aimed to identify novel plasma biomarkers of neurodegeneration and inflammation in a mouse model of stroke induced by distal middle cerebral artery occlusion. Using targeted lipidomic and global untargeted metabolomic profiling of plasma collected from aged male mice 24 h after stroke and weekly thereafter for 7 weeks, we discovered distinct acute and chronic signatures. In the acute phase, we observed elevations in myelin-associated lipids, including sphingomyelin (SM) and hexosylceramide (HCER) lipid species, indicating brain lipid catabolism. In the chronic phase, we identified 12-hydroxyeicosatetraenoic acid (12-HETE) as a putative biomarker of prolonged inflammation, consistent with our previous observation of a biphasic pro-inflammatory response to ischemia in the mouse brain. These results provide insight into the metabolic alterations detectable in the plasma after stroke and highlight the potential of myelin degradation products and arachidonic acid derivatives as biomarkers of neurodegeneration and inflammation, respectively. These discoveries lay the groundwork for further validation in human studies and may improve stroke management strategies.

Mechanistic insights on TLR-4 mediated inflammatory pathway in neurodegenerative diseases

Neurodegenerative diseases (NDDs) pose a significant issue in healthcare, needing a thorough knowledge of their complex molecular mechanisms. A diverse set of cell signaling mediators and their interactions play critical roles in neuroinflammation. The release of pro-inflammatory mediators in response to neural dysfunction is detrimental to normal cell survival. Moreover, the important role of nuclear factor-κB (NF-κB) in the central nervous system through Toll-like receptor (TLR) activation has been well established. Therefore, through a comprehensive review of current research and experimentation, this investigation elucidates the interactions between novel pharmacological agents (TLR-4/NF-κB inhibitors) and neurodegeneration encompassing Alzheimer's, Parkinson's, Huntington's disease, amyotrophic lateral sclerosis and stroke. Insights garnered from this exploration underscore the potential of TLR-4 as a therapeutic target. Through the revelation of these insights, our aim is to establish a foundation for the development of enhanced and focused therapeutic approaches in the continuous endeavor to combat neurodegeneration. This review thus serves as a roadmap, guiding future research endeavors toward innovative strategies for combatting the complex interplay between TLR-4 signaling and NDDs.

The link between Alzheimer's disease and stroke: A detrimental synergism

Being age-related disorders, both Alzheimer's disease (AD) and stroke share multiple risk factors, such as hypertension, smoking, diabetes, and apolipoprotein E (APOE) Ɛ4 genotype, and coexist in patients. Accumulation of amyloid-β plaques and neurofibrillary tangled impair cognitive potential, leading to AD. Blocked blood flow in the neuronal tissues, causes neurodegeneration and cell death in stroke. AD is commonly characterized by cerebral amyloid angiopathy, which significantly elevates the risk of hemorrhagic stroke. Patients with AD and stroke have been both reported to exhibit greater cognitive impairment, followed by multiple pathophysiological mechanisms shared between the two. The manuscript aims to elucidate the relationship between AD and stroke, as well as the common pathways and risk factors while understanding the preventive therapies that might limit the negative impacts of this correlation, with diagnostic modalities and current AD treatments. The authors provide a comprehensive review of the link and aid the healthcare professionals to identify suitable targets and risk factors, that may retard cognitive decline and neurodegeneration in patients. However, more intricate research is required in this regard and an interdisciplinary approach that would target both the vascular and neurodegenerative factors would improve the quality of life in AD patients.

β-hydroxybutyrate and ischemic stroke: roles and mechanisms

Stroke is a significant global burden, causing extensive morbidity and mortality. In metabolic states where glucose is limited, ketone bodies, predominantly β-hydroxybutyrate (BHB), act as alternative fuel sources. Elevated levels of BHB have been found in the ischemic hemispheres of animal models of stroke, supporting its role in the pathophysiology of cerebral ischemia. Clinically, higher serum and urinary BHB concentrations have been associated with adverse outcomes in ischemic stroke, highlighting its potential utility as a prognostic biomarker. In both animal and cellular models, exogenous BHB administration has exhibited neuroprotective effects, reduction of infarct size, and improvement of neurological outcomes. In this review, we focus on the role of BHB before and after ischemic stroke, with an emphasis on the therapeutic potential and mechanisms of ketone administration after ischemic stroke.

Treatment of vascular dementia in female rats with AV-001, an Angiopoietin-1 mimetic peptide, improves cognitive function

Background

Vascular dementia (VaD) is a complex neurodegenerative disorder. We previously found that treatment of VaD in middle-aged male rats subjected to multiple microinfarction (MMI) with AV-001, a Tie2 receptor agonist, significantly improves cognitive function. Age and sex affect the development and response of VaD to therapeutic intervention. Thus, the present study investigated the therapeutic effect of AV-001 on VaD in aged female rats subjected to MMI.

Methods

Female 18-month-old Wistar rats were subjected to MMI by injecting either 1,000 (low dose, LD-MMI) or 6,000 (high dose, HD-MMI) cholesterol crystals of size 70-100 μm into the right internal carotid artery. AV-001 (1 μg/Kg, i.p.) was administered once daily after MMI for 1 month, with treatment initiated 1 day after MMI. A battery of behavioral tests to examine sensorimotor and cognitive functions was performed at 21-28 days after MMI. All rats were sacrificed at 1 month after MMI.

Results

Aged female rats subjected to LD-MMI exhibit severe neurological deficits, memory impairment, and significant white matter (WM) and oligodendrogenesis injury in the corpus callosum compared with control rats. HD-MMI in aged female rats induces significant anxiety- and depression-like behaviors, which were not detected in LD-MMI aged female rats. Also, HD-MMI induces significantly increased WM injury compared to LD-MMI. AV-001 treatment of LD-MMI and HD-MMI increases oligodendrogenesis, myelin and axon density in the corpus callosum and striatal WM bundles, promotes WM integrity and attenuates neurological and cognitive deficits. Additionally, both LD-MMI and HD-MMI rats exhibit a significant increase, while AV-001 significantly decreases the levels of inflammatory factors in the cerebrospinal fluid (CSF).

Conclusion

MMI reduces oligodendrogenesis, and induces demyelination, axonal injury and WM injury, and causes memory impairment, while HD-MMI induces increased WM injury and further depression-like behaviors compared to LD-MMI rats. AV-001 has a therapeutic effect on aged female rats with MMI by reducing WM damage and improving neuro-cognitive outcomes.

The activation of AMPK/PGC-1α/GLUT4 signaling pathway through early exercise improves mitochondrial function and mitigates ischemic brain damage

Mitochondria play a crucial role in maintaining cellular energy supply and serve as a source of energy for repairing nerve damage following a stroke. Given that exercise has the potential to enhance energy metabolism, investigating the impact of exercise on mitochondrial function provides a plausible mechanism for stroke treatment. In our study, we established the middle cerebral artery occlusion (MCAO) model in Sprague-Dawley rats and implemented early exercise intervention. Neurological severity scores, beam-walking test score, and weight were used to evaluate neurological function. The volume of cerebral infarction was measured by MRI. Nerve cell apoptosis was detected by TUNEL staining. Mitochondrial morphology and structure were detected by mitochondrial electron microscopy. Mitochondrial function was assessed using membrane potential and ATP measurements. Western blotting was used to detect the protein expression of AMPK/PGC-1α/GLUT4. Through the above experiments, we found that early exercise improved neurological function in rats after MCAO, reduced cerebral infarction volume and neuronal apoptosis, promoted the recovery of mitochondrial morphology and function. We further examined the protein expression of AMPK/PGC-1α/GLUT4 signaling pathway and confirmed that early exercise was able to increase its expression. Therefore, we suggest that early exercise initiated the AMPK/PGC-1α/GLUT4 signaling pathway, restoring mitochondrial function and augmenting energy supply. This, in turn, effectively improved both nerve and body function in rats following ischemic stroke.

Potential of CBD Acting on Cannabinoid Receptors CB1 and CB2 in Ischemic Stroke

Stroke is one of the leading causes of death. It not only affects adult people but also many children. It is estimated that, every year, 15 million people suffer a stroke worldwide. Among them, 5 million people die, while 5 million people are left permanently disabled. In this sense, the research to find new treatments should be accompanied with new therapies to combat neuronal death and to avoid developing cognitive impairment and dementia. Phytocannabinoids are among the compounds that have been used by mankind for the longest period of history. Their beneficial effects such as pain regulation or neuroprotection are widely known and make them possible therapeutic agents with high potential. These compounds bind cannabinoid receptors CB1 and CB2. Unfortunately, the psychoactive side effect has displaced them in the vast majority of areas. Thus, progress in the research and development of new compounds that show efficiency as neuroprotectors without this psychoactive effect is essential. On the one hand, these compounds could selectively bind the CB2 receptor that does not show psychoactive effects and, in glia, has opened new avenues in this field of research, shedding new light on the use of cannabinoid receptors as therapeutic targets to combat neurodegenerative diseases such as Alzheimer's, Parkinson's disease, or stroke. On the other hand, a new possibility lies in the formation of heteromers containing cannabinoid receptors. Heteromers are new functional units that show new properties compared to the individual protomers. Thus, they represent a new possibility that may offer the beneficial effects of cannabinoids devoid of the unwanted psychoactive effect. Nowadays, the approval of a mixture of CBD (cannabidiol) and Δ9-THC (tetrahydrocannabinol) to treat the neuropathic pain and spasticity in multiple sclerosis or purified cannabidiol to combat pediatric epilepsy have opened new therapeutic possibilities in the field of cannabinoids and returned these compounds to the front line of research to treat pathologies as relevant as stroke.

Revolutionizing Stroke Care: Nanotechnology-Based Brain Delivery as a Novel Paradigm for Treatment and Diagnosis

Stroke, a severe medical condition arising from abnormalities in the coagulation-fibrinolysis cycle and metabolic processes, results in brain cell impairment and injury due to blood flow obstruction within the brain. Prompt and efficient therapeutic approaches are imperative to control and preserve brain functions. Conventional stroke medications, including fibrinolytic agents, play a crucial role in facilitating reperfusion to the ischemic brain. However, their clinical efficacy is hampered by short plasma half-lives, limited brain tissue distribution attributed to the blood-brain barrier (BBB), and lack of targeted drug delivery to the ischemic region. To address these challenges, diverse nanomedicine strategies, such as vesicular systems, polymeric nanoparticles, dendrimers, exosomes, inorganic nanoparticles, and biomimetic nanoparticles, have emerged. These platforms enhance drug pharmacokinetics by facilitating targeted drug accumulation at the ischemic site. By leveraging nanocarriers, engineered drug delivery systems hold the potential to overcome challenges associated with conventional stroke medications. This comprehensive review explores the pathophysiological mechanism underlying stroke and BBB disruption in stroke. Additionally, this review investigates the utilization of nanocarriers for current therapeutic and diagnostic interventions in stroke management. By addressing these aspects, the review aims to provide insight into potential strategies for improving stroke treatment and diagnosis through a nanomedicine approach.

Post-mortem changes of anisotropic mechanical properties in the porcine brain assessed by MR elastography

Knowledge of the mechanical properties of brain tissue in vivo is essential to understanding the mechanisms underlying traumatic brain injury (TBI) and to creating accurate computational models of TBI and neurosurgical simulation. Brain white matter, which is composed of aligned, myelinated, axonal fibers, is structurally anisotropic. White matter in vivo also exhibits mechanical anisotropy, as measured by magnetic resonance elastography (MRE), but measurements of anisotropy obtained by mechanical testing of white matter ex vivo have been inconsistent. The minipig has a gyrencephalic brain with similar white matter and gray matter proportions to humans and therefore provides a relevant model for human brain mechanics. In this study, we compare estimates of anisotropic mechanical properties of the minipig brain obtained by identical, non-invasive methods in the live (in vivo) and dead animals (in situ). To do so, we combine wave displacement fields from MRE and fiber directions derived from diffusion tensor imaging (DTI) with a finite element-based, transversely-isotropic nonlinear inversion (TI-NLI) algorithm. Maps of anisotropic mechanical properties in the minipig brain were generated for each animal alive and at specific times post-mortem. These maps show that white matter is stiffer, more dissipative, and more anisotropic than gray matter when the minipig is alive, but that these differences largely disappear post-mortem, with the exception of tensile anisotropy. Overall, brain tissue becomes stiffer, less dissipative, and less mechanically anisotropic post-mortem. These findings emphasize the importance of testing brain tissue properties in vivo.

Statement of Significance

In this study, MRE and DTI in the minipig were combined to estimate, for the first time, anisotropic mechanical properties in the living brain and in the same brain after death. Significant differences were observed in the anisotropic behavior of brain tissue post-mortem. These results demonstrate the importance of measuring brain tissue properties in vivo as well as ex vivo, and provide new quantitative data for the development of computational models of brain biomechanics.

Protection of Gueichih-Fuling-Wan on cerebral ischemia-induced brain injury in rodents is mediated by trans-cinnamaldehyde via inhibition of neuroinflammation and apoptosis

Background

Stroke is the leading cause of mortality and morbidity worldwide, and an effective therapeutic strategy for the prevention of patients with cerebral ischemia induced brain injury is lacking. Traditional Chinese medicine with neuroprotective activities might be beneficial and provide alternative therapeutic opportunities for cerebral ischemia.

Purposes

This study aimed to evaluate the neuroprotection and possible mechanisms of Gueichih-Fuling-Wan (GFW), its' constitutive herbs, and their active compounds on cerebral ischemia/reperfusion (I/R)-induced brain injury in rodents.

Methods

Various doses of extracts (0.25, 0.5, and 1.0 g/kg) of GFW and five constituent herbs (Cinnamomi Cortex, CC; Poria cocos, PC; Paeonia lactifloa, PL; Paeonia suffruticosa, PS and Prunus perisica, PP) were orally administered. Different doses of active compounds (0.5, 1.0, and 2.0 mg/kg) of GFW such as cinnamaldehyde, cinnamic acid (from CC), paeoniflorin (from PL), and paeonol (from PS) were intraperitoneally administered. Their effects on cerebral ischemia/ reperfusion (I/R)induced brain injury in rodents were evaluated.

Results

GFW, its' constituent herbs, and the active compounds reduced the infarct area dose-dependently (***P < 0.001). Cinnamaldehyde showed the most significant reduction (***P < 0.001). Therefore, trans-cinnamaldehyde (TCA) was further used to evaluate the neuroprotective mechanism of the I/R-induced brain injury. TCA (10, 20, 30 mg/ kg, p.o.) showed an inhibitory effect of I/R-induced brain damage in mice in a dose-dependent manner. Besides, GFW and TCA dose-dependently reduced the COX-2 protein expression level, and TCA reduced the TUNEL (+) apoptosis. TCA dose-dependently increased the pro-survival NR2A and Bcl-2 protein expression level and decreased the pro-apoptotic NR2B and cytochrome c, caspase 9, and caspase 3 expression (***P < 0.001).

Conclusion

The above data revealed that GFW, its' constituent herbs, and active compounds protected against I/R-induced brain injury in rodents. TCA from CC might participate in GFW protecting against cerebral ischemia-induced brain injury by inhibiting neuroinflammation and apoptosis.

A role for astrocytic insulin-like growth factor I receptors in the response to ischemic insult

Increased neurotrophic support, including insulin-like growth factor I (IGF-I), is an important aspect of the adaptive response to ischemic insult. However, recent findings indicate that the IGF-I receptor (IGF-IR) in neurons plays a detrimental role in the response to stroke. Thus, we investigated the role of astrocytic IGF-IR on ischemic insults using tamoxifen-regulated Cre deletion of IGF-IR in glial fibrillary acidic protein (GFAP) astrocytes, a major cellular component in the response to injury. Ablation of IGF-IR in astrocytes (GFAP-IGF-IR KO mice) resulted in larger ischemic lesions, greater blood-brain-barrier disruption and more deteriorated sensorimotor coordination. RNAseq detected increases in inflammatory, cell adhesion and angiogenic pathways, while the expression of various classical biomarkers of response to ischemic lesion were significantly increased at the lesion site compared to control littermates. While serum IGF-I levels after injury were decreased in both control and GFAP-IR KO mice, brain IGF-I mRNA expression show larger increases in the latter. Further, greater damage was also accompanied by altered glial reactivity as reflected by changes in the morphology of GFAP astrocytes, and relative abundance of ionized calcium binding adaptor molecule 1 (Iba 1) microglia. These results suggest a protective role for astrocytic IGF-IR in the response to ischemic injury.

Review of Cerebral Collateral Circulation and Insight into Cardiovascular Strategies to Limit Collateral Damage in Ischemic Stroke

Cerebral collateral circulation is a dynamic and adaptive process by which alternative vascular pathways supply perfusion to ischemic brain tissue in the event of an arterial occlusion. This complicated network of blood vessels that acts as a natural bypass plays a pivotal role in stroke pathophysiology and has become a key area of study given its significance in stroke treatment and patient outcomes. In this review, we will study the factors influencing the formation, recruitment, and endurance of collateral vessels; discuss imaging modalities for quantitative and qualitative assessment of this network; explore the role of collaterals in stroke management; and highlight several cardiovascular strategies to minimize damage to collaterals and optimize stroke outcomes.

Advanced Nano-Drug Delivery Systems in the Treatment of Ischemic Stroke

In recent years, the frequency of strokes has been on the rise year by year and has become the second leading cause of death around the world, which is characterized by a high mortality rate, high recurrence rate, and high disability rate. Ischemic strokes account for a large percentage of strokes. A reperfusion injury in ischemic strokes is a complex cascade of oxidative stress, neuroinflammation, immune infiltration, and mitochondrial damage. Conventional treatments are ineffective, and the presence of the blood-brain barrier (BBB) leads to inefficient drug delivery utilization, so researchers are turning their attention to nano-drug delivery systems. Functionalized nano-drug delivery systems have been widely studied and applied to the study of cerebral ischemic diseases due to their favorable biocompatibility, high efficiency, strong specificity, and specific targeting ability. In this paper, we briefly describe the pathological process of reperfusion injuries in strokes and focus on the therapeutic research progress of nano-drug delivery systems in ischemic strokes, aiming to provide certain references to understand the progress of research on nano-drug delivery systems (NDDSs).

Anti-Apoptotic Effects of AMPA Receptor Antagonist Perampanel in Early Brain Injury After Subarachnoid Hemorrhage in Mice

This study was aimed to investigate if acute neuronal apoptosis is induced by activation of AMPA (α-amino-3-hydroxy-5-methyl-4-isoxazole propionate) receptors (AMPARs) and inhibited by a clinically available selective AMPAR antagonist and antiepileptic drug perampanel (PER) in subarachnoid hemorrhage (SAH), and if the mechanisms include upregulation of an inflammation-related matricellular protein periostin. Sham-operated and endovascular perforation SAH mice randomly received an administration of 3 mg/kg PER or the vehicle intraperitoneally. Post-SAH neurological impairments and increased caspase-dependent neuronal apoptosis were associated with activation of AMPAR subunits GluA1 and GluA2, and upregulation of periostin and proinflammatory cytokines interleukins-1β and -6, all of which were suppressed by PER. PER also inhibited post-SAH convulsion-unrelated increases in the total spectral power on video electroencephalogram (EEG) monitoring. Intracerebroventricularly injected recombinant periostin blocked PER's anti-apoptotic effects on neurons. An intracerebroventricular injection of a selective agonist for GluA1 and GluA2 aggravated neurological impairment, neuronal apoptosis as well as periostin upregulation, but did not increase the EEG total spectral power after SAH. A higher dosage (10 mg/kg) of PER had even more anti-apoptotic effects compared with 3 mg/kg PER. Thus, this study first showed that AMPAR activation causes post-SAH neuronal apoptosis at least partly via periostin upregulation. A clinically available AMPAR antagonist PER appears to be neuroprotective against post-SAH early brain injury through the anti-inflammatory and anti-apoptotic effects, independent of the antiepileptic action, and deserves further study.

CA-UNet Segmentation Makes a Good Ischemic Stroke Risk Prediction

Stroke is still the World's second major factor of death, as well as the third major factor of death and disability. Ischemic stroke is a type of stroke, in which early detection and treatment are the keys to preventing ischemic strokes. However, due to the limitation of privacy protection and labeling difficulties, there are only a few studies on the intelligent automatic diagnosis of stroke or ischemic stroke, and the results are unsatisfactory. Therefore, we collect some data and propose a 3D carotid Computed Tomography Angiography (CTA) image segmentation model called CA-UNet for fully automated extraction of carotid arteries. We explore the number of down-sampling times applicable to carotid segmentation and design a multi-scale loss function to resolve the loss of detailed features during the process of down-sampling. Moreover, based on CA-Unet, we propose an ischemic stroke risk prediction model to predict the risk in patients using their 3D CTA images, electronic medical records, and medical history. We have validated the efficacy of our segmentation model and prediction model through comparison tests. Our method can provide reliable diagnoses and results that benefit patients and medical professionals.

Sinigrin improves cerebral ischaemia-reperfusion injury by inhibiting the TLR4 pathway-mediated oxidative stress

Cerebral ischaemia-reperfusion (CIR) injury occurs in stroke patients after the restoration of cerebral perfusion. Sinigrin, a phytochemical found in cruciferous vegetables, exhibits strong antioxidant activity. This study investigated the role of sinigrin in oxidative stress using a CIR injury model. The effects of sinigrin were studied in middle cerebral artery occlusion (MCAO) rats and oxygen-glucose deprivation/reoxygenation (OGD/R)-injured SH-SY5Y cells. Sinigrin treatment improved brain injury and neurological deficits induced by MCAO surgery in rats. Sinigrin inhibited apoptosis in brain tissues and SH-SY5Y cells following OGD/R induction. Additionally, sinigrin elevated the levels of superoxide dismutase (SOD), glutathione (GSH) and glutathione peroxidase (GSH-Px) while reducing malondialdehyde (MDA) levels. Furthermore, sinigrin inhibited the toll-like receptor 4 (TLR4)/myeloid differentiation factor 88 (MyD88) signalling pathway. The anti-apoptotic and antioxidant activities of sinigrin in OGD/R-injured SH-SY5Y cells were reversed by TLR4 overexpression. In conclusion, sinigrin inhibits oxidative stress in CIR injury by suppressing the TLR4/MyD88 signalling pathway.

Addition of Vitamin C Does Not Decrease Neuron-Specific Enolase Levels in Adult Survivors of Cardiac Arrest-Results of a Randomized Trial

Background and Objectives: Survival with favorable neurologic outcomes after out-of-hospital cardiac arrest (OHCA) remains elusive. Post-cardiac arrest syndrome (PCAS) involves myocardial and neurological injury, ischemia-reperfusion response, and underlying pathology. Neurologic injury is a crucial determinant of survival and functional outcomes, with damage caused by free radicals among the responsible mechanisms. This study explores the feasibility of adding intravenous vitamin C to the treatment of OHCA survivors, aiming to mitigate PCAS. Vitamin C, a nutrient with antioxidative and free radical-scavenging properties, is often depleted in critically ill patients. Materials and Methods: This randomized, double-blinded trial was conducted at a tertiary-level university hospital with adult OHCA survivors. Participants received either standard care or the addition of 1.5 g of intravenous vitamin C every 12 h for eight consecutive doses. Neurologic injury was assessed using neuron-specific enolase (NSE) levels, with additional clinical and laboratory outcomes, such as enhanced neuroprognostication factors, inflammatory markers, and cardiac parameters. Results: NSE levels were non-significantly higher in patients who received vitamin C compared to the placebo group (55.05 µg/L [95% confidence interval (CI) 26.7-124.0] vs. 39.4 µg/L [95% CI 22.6-61.9], p > 0.05). Similarly, a non-significantly greater proportion of patients in the vitamin C group developed myoclonus in the first 72 h. We also observed a non-significantly shorter duration of mechanical ventilation, fewer arrhythmias, and reduced length of stay in the intensive care unit in the group of patients who received vitamin C (p = 0.031). However, caution is warranted in interpretation of our results due to the small number of participants. Conclusions: Our findings suggest that intravenous vitamin C should not be used outside of clinical trials for OHCA survivors. Due to the small sample size and conflicting results, further research is needed to determine the potential role of vitamin C in post-cardiac arrest care.

Ocimum sanctum [Tulsi] as a Potential Immunomodulator for the Treatment of Ischemic Injury in the Brain

Stroke causes brain damage and is one of the main reasons for death. Most survivors of stroke face long-term physical disabilities and cognitive dysfunctions. In addition, they also have persistent emotional and behavioral changes. The two main treatments that are effective are reperfusion with recombinant tissue plasminogen activator and recanalization of penumbra using mechanical thrombectomy. However, these treatments are suitable only for a few patients due to limitations such as susceptibility to hemorrhage and the requirement for administering tissue plasminogen activators within the short therapeutic window during the early hours following a stroke. The paucity of interventions and treatments could be because of the multiple pathological mechanisms induced in the brain by stroke. The ongoing immune response following stroke has been attributed to the worsening brain injury. Hence, novel compounds with immunomodulatory properties that could improve the outcome of stroke patients are required. Natural compounds and medicinal herbs with anti-inflammatory activities and having minimal or no adverse systemic effect could be beneficial in treating stroke. Ocimum sanctum is a medicinal herb that can be considered an effective therapeutic option for ischemic brain injury. Ocimum sanctum, commonly known as holy basil or "Tulsi," is mentioned as the "Elixir of Life" for its healing powers. Since antiquity, Tulsi has been used in the Ayurvedic and Siddha medical systems to treat several diseases. It possesses immuno-modulatory activity, which can alter cellular and humoral immune responses. Tulsi can be considered a potential option as an immuno-modulator for treating various diseases, including brain stroke. In this review, we will focus on the immunomodulatory properties of Tulsi, specifically its effect on both innate and adaptive immunity, as well as its antioxidant and antiinflammatory properties, which could potentially be effective in treating ongoing immune reactions following ischemic brain injury.

Genetics in Ischemic Stroke: Current Perspectives and Future Directions

Ischemic stroke is a heterogeneous condition influenced by a combination of genetic and environmental factors. Recent advancements have explored genetics in relation to various aspects of ischemic stroke, including the alteration of individual stroke occurrence risk, modulation of treatment response, and effectiveness of post-stroke functional recovery. This article aims to review the recent findings from genetic studies related to various clinical and molecular aspects of ischemic stroke. The potential clinical applications of these genetic insights in stratifying stroke risk, guiding personalized therapy, and identifying new therapeutic targets are discussed herein.

Biomimetic nanoparticles in ischemic stroke therapy

Abstract

Ischemic stroke is one of the most severe neurological disorders with limited therapeutic strategies. The utilization of nanoparticle drug delivery systems is a burgeoning field and has been widely investigated. Among these, biomimetic drug delivery systems composed of biogenic membrane components and synthetic nanoparticles have been extensively highlighted in recent years. Biomimetic membrane camouflage presents an effective strategy to prolong circulation, reduce immunogenicity and enhance targeting. For one thing, biomimetic nanoparticles reserve the physical and chemical properties of intrinsic nanoparticle. For another, the biological functions of original source cells are completely inherited. Compared to conventional surface modification methods, this approach is more convenient and biocompatible. In this review, membrane-based nanoparticles derived from different donor cells were exemplified. The prospect of future biomimetic nanoparticles in ischemic stroke therapy was discussed.

Graphic abstract

P25/CDK5-mediated Tau Hyperphosphorylation in Both Ipsilateral and Contralateral Cerebra Contributes to Cognitive Deficits in Post-stroke Mice

OBJECTIVE

Post-stroke cognitive impairment (PSCI) develops in approximately one-third of stroke survivors and is associated with ingravescence. Nonetheless, the biochemical mechanisms underlying PSCI remain unclear. The study aimed to establish an ischemic mouse model by means of transient unilateral middle cerebral artery occlusions (MCAOs) and to explore the biochemical mechanisms of p25/cyclin-dependent kinase 5 (CDK5)-mediated tau hyperphosphorylation on the PSCI behavior.

METHODS

Cognitive behavior was investigated, followed by the detection of tau hyperphosphorylation, mobilization, activation of kinases and/or inhibition of phosphatases in the lateral and contralateral cerebrum of mice following ischemia in MACO mice. Finally, we treated HEK293/tau cells with oxygen-glucose deprivation (OGD) and a CDK5 inhibitor (Roscovitine) or a GSK3β inhibitor (LiCl) to the roles of CDK5 and GSK3β in mediating ischemia-reperfusion-induced tau phosphorylation.

RESULTS

Ischemia induced cognitive impairments within 2 months, as well as causing tau hyperphosphorylation and its localization to neuronal somata in both ipsilateral and contralateral cerebra. Furthermore, p25 that promotes CDK5 hyperactivation had significantly higher expression in the mice with MCAO than in the shamoperation (control) group, while the expression levels of protein phosphatase 2 (PP2A) and the phosphorylation level at Tyr307 were comparable between the two groups. In addition, the CDK5 inhibitor rescued tau from hyperphosphorylation induced by OGD.

CONCLUSION

These findings demonstrate that upregulation of CDK5 mediates tau hyperphosphorylation and localization in both ipsilateral and contralateral cerebra, contributing to the pathogenesis of PSCI.

Biomarkers of Cardiovascular Diseases in Saliva and Gingival Crevicular Fluid: A Review

Due to the fact that cardiovascular diseases (CVDs) have become the most serious problem in public health, there is a need for new and efficient methods for screening and early detection. In the recent literature, saliva and gingival crevicular fluid (GCF) have been gaining recognition as sources of many potential biomarkers of various systemic diseases, mainly because of correlation between the level of some compounds in the blood and saliva and association between the composition of saliva and health status. In this review, we summarize published findings of patients with atherosclerosis, arterial hypertension, coronary artery disease (CAD), acute coronary syndrome (ACS), and stroke in the context of clinical utility of saliva and GCF in diagnosing and assessing CVD severity. We hypothesize that substances in saliva including inflammatory markers, enzymes, or hormones might become novel contributors to the diagnosis and screening of CVDs. In particular, C-reactive protein (CRP), tumor necrosis alpha (TNFα), and cortisol seem to be the most promising. However, further investigation is warranted to determine the most effective markers and methods for their analysis.

Mediation effect of stroke recurrence in the association between post-stroke interleukin-6 and functional disability

AIM

Post-stroke inflammation increases the risk of functional disability through enlarged cerebral infarct size directly and follow-up stroke event indirectly. We aimed to use post-stroke proinflammatory cytokine interleukin-6 (IL-6) as a marker of inflammatory burden and quantify post-stroke inflammation's direct and indirect effect on functional disability.

METHODS

We analyzed patients with acute ischemic stroke admitted to 169 hospitals in the Third China National Stroke Registry. Blood samples were collected within 24 h of admission. Stroke recurrence and functional outcome measured by the modified Rankin scale (mRS) were assessed via face-to-face interviews at 3 months. Functional disability was defined as an mRS score ≥2. Mediation analyses under the counterfactual framework were performed to examine the potential causal chain in which stroke recurrence may mediate the relationship between IL-6 and functional outcome.

RESULTS

Among the 7053 analyzed patients, the median (interquartile range [IQR]) NIHSS score was 3 (1-5), and the median (IQR) level of IL-6 was 2.61 (1.60-4.73) pg/mL. Stroke recurrence was observed in 458 (6.5%) patients, and functional disability was seen in 1708 (24.2%) patients at the 90-day follow-up. Per stand deviation (4.26 pg/mL) increase in the concentration of IL-6 was associated with an increased risk of stroke recurrence (adjusted odds ratio [aOR], 1.19; 95% CI, 1.09-1.29) and disability (aOR, 1.22; 95% CI, 1.15-1.30) within 90 days. Mediation analyses revealed that 18.72% (95% CI, 9.26%-28.18%) of the relationship between IL-6 and functional disability was mediated by stroke recurrence.

CONCLUSIONS

Stroke recurrence mediates less than 20% of the association between IL-6 and functional outcome at 90 days among patients with acute ischemic stroke. In addition to typical secondary prevention strategies for preventing stroke recurrence, more attention should be paid to novel anti-inflammatory therapy to improve functional outcomes directly.

The Interplay between Mitochondrial Dysfunction and Ferroptosis during Ischemia-Associated Central Nervous System Diseases

Cerebral ischemia, a leading cause of disability and mortality worldwide, triggers a cascade of molecular and cellular pathologies linked to several central nervous system (CNS) disorders. These disorders primarily encompass ischemic stroke, Alzheimer's disease (AD), Parkinson's disease (PD), epilepsy, and other CNS conditions. Despite substantial progress in understanding and treating the underlying pathological processes in various neurological diseases, there is still a notable absence of effective therapeutic approaches aimed specifically at mitigating the damage caused by these illnesses. Remarkably, ischemia causes severe damage to cells in ischemia-associated CNS diseases. Cerebral ischemia initiates oxygen and glucose deprivation, which subsequently promotes mitochondrial dysfunction, including mitochondrial permeability transition pore (MPTP) opening, mitophagy dysfunction, and excessive mitochondrial fission, triggering various forms of cell death such as autophagy, apoptosis, as well as ferroptosis. Ferroptosis, a novel type of regulated cell death (RCD), is characterized by iron-dependent accumulation of lethal reactive oxygen species (ROS) and lipid peroxidation. Mitochondrial dysfunction and ferroptosis both play critical roles in the pathogenic progression of ischemia-associated CNS diseases. In recent years, growing evidence has indicated that mitochondrial dysfunction interplays with ferroptosis to aggravate cerebral ischemia injury. However, the potential connections between mitochondrial dysfunction and ferroptosis in cerebral ischemia have not yet been clarified. Thus, we analyzed the underlying mechanism between mitochondrial dysfunction and ferroptosis in ischemia-associated CNS diseases. We also discovered that GSH depletion and GPX4 inactivation cause lipoxygenase activation and calcium influx following cerebral ischemia injury, resulting in MPTP opening and mitochondrial dysfunction. Additionally, dysfunction in mitochondrial electron transport and an imbalanced fusion-to-fission ratio can lead to the accumulation of ROS and iron overload, which further contribute to the occurrence of ferroptosis. This creates a vicious cycle that continuously worsens cerebral ischemia injury. In this study, our focus is on exploring the interplay between mitochondrial dysfunction and ferroptosis, which may offer new insights into potential therapeutic approaches for the treatment of ischemia-associated CNS diseases.

Melatonin delivered in solid lipid nanoparticles ameliorated its neuroprotective effects in cerebral ischemia

The current study explores the potential of melatonin (MLT)-loaded solid lipid nanoparticles (MLT-SLNs) for better neuroprotective effects in ischemic stroke. MLT-SLNs were prepared using lipid matrix of palmityl alcohol with a mixture of surfactants (Tween 40, Span 40, Myrj 52) for stabilizing the lipid matrix. MLT-SLNs were tested for physical and chemical properties, thermal and polymorphic changes, in vitro drug release and in vivo neuroprotective studies in rats using permanent middle cerebral artery occlusion (p-MCAO) model. The optimized MLT-SLNs showed particle size of ∼159 nm, zeta potential of -29.6 mV and high entrapment efficiency ∼92%. Thermal and polymorphic studies showed conversion of crystalline MLT to amorphous form after its entrapment in lipid matrix. MLT-SLNs displayed a sustained release pattern compared to MLT dispersion. MLT-SLNs significantly enhanced the neuroprotective profile of MLT ascertained by reduced brain infarction, recovered behavioral responses, low expression of inflammatory markers and improved oxidation protection in rats. MLT-SLNs also showed reduced hepatotoxicity compared to p-MCAO. From these outcomes, it is evidenced that MLT-SLNs have improved neuroprotection as compared to MLT dispersion and thereby present a promising approach to deliver MLT to the brain for better therapeutic outcomes in ischemic stroke.

Quercetin Alleviated Inflammasome-Mediated Pyroptosis and Modulated the mTOR/P70S6/P6/eIF4E/4EBP1 Pathway in Ischemic Stroke

Stroke ranks as the world's second most prevalent cause of mortality, and it represents a major public health concern with profound economic and social implications. In the present study, we elucidated the neuroprotective role of quercetin on NLRP3-associated pyroptosis, Nrf2-coupled anti-inflammatory, and mTOR-dependent downstream pathways. Male Sprague Dawley rats were subjected to 72 h of transient middle cerebral artery ischemia, followed by the administration of 10 mg/kg of quercetin. Our findings demonstrated that MCAO induced elevated ROS which were coupled to inflammasome-mediated pyroptosis and altered mTOR-related signaling proteins. We performed ELISA, immunohistochemistry, and Western blotting to unveil the underlying role of the Nrf2/HO-1 and PDK/AKT/mTOR pathways in the ischemic cortex and striatum. Our results showed that quercetin post-treatment activated the Nrf2/HO-1 cascade, reversed pyroptosis, and modulated the autophagy-related pathway PDK/AKT/mTOR/P70S6/P6/eIF4E/4EBP1. Further, quercetin enhances the sequestering effect of 14-3-3 and reversed the decrease in interaction between p-Bad and 14-3-3 and p-FKHR and 14-3-3. Our findings showed that quercetin exerts its protective benefits and rescues neuronal damage by several mechanisms, and it might be a viable neuroprotective drug for ischemic stroke therapy.

Effect of abnormal values of three temperature indicators on ischemic stroke hospital admissions in Guangzhou, China

Abnormal temperature has important effects on the occurrence of ischemic stroke (IS). However, relatively less efforts have been taken to systematically unravel the association between various abnormal temperature and IS hospital admission. Focusing on three temperature indicators (i.e., mean temperature, maximum temperature, and minimum temperature), this study attempts to analyse how their abnormal values affect IS hospital admission. The dataset covers the period between September 17, 2012 and August 28, 2018, and includes a total of 1464 cases who were admitted to the hospital for the first onset of IS and lived in the main urban area of Guangzhou. The study adopts the time-stratified case-crossover analysis. Abnormal values of temperature were measured using the 2.5th and 97.5th quantile values of each temperature indicator, with the former refers to a low value whereas the latter a high one. The effects of abnormal temperature on IS hospital admission were assessed through calculating the relative risks induced by the low and high values (the median values of each temperature indicators were taken as the references). The results show that the risk window periods for IS hospital admission associated with the low values of the temperature indicators are the lags of 3-7 days and 18-19 days. The risks of high temperature values on IS admission, however, are insignificant with either one-day lag or cumulative lag. As to different population groups, females show higher risks of IS hospital admission at low temperature values than males; and elderly people, compared with young people, are more vulnerable to low temperature values. To cities with similar climate of Guangzhou, particular attention should be paid to the impact of low temperature values, especially the low value of minimum temperature, on IS admission, and to females and elderly people who are more sensitive to abnormal temperatures.

Hemiplegia resulting from acute carbon monoxide poisoning

Carbon monoxide (CO) poisoning can cause neurological complications such as movement disorders and cognitive impairment through hypoxic brain damage. Although peripheral neuropathy of the lower extremities is a known complication of CO poisoning, hemiplegia is very rare. In our case, a patient who developed left hemiplegia due to acute CO poisoning received early hyperbaric oxygen treatment (HBOT). The patient had left hemiplegia and anisocoria at the beginning of HBOT. Her Glasgow coma score was 8. A total of five sessions of HBOT at 243.2 kPa for 120 minutes were provided. At the end of the 5th session, the patient's hemiplegia and anisocoria were completely resolved. Her Glasgow coma score was 15. After nine months of follow-up, she continues to live independently with no sequelae, including delayed neurological sequelae. Clinicians should be aware that CO poisoning can (rarely) present with hemiplegia.

An integrated measure of GABA to characterize post-stroke plasticity

Stroke is a major cause of death and chronic neurological disability. Despite the improvements in stroke care, the number of patients affected by stroke keeps increasing and many stroke survivors are left permanently disabled. Current therapies are limited in efficacy. Understanding the neurobiological mechanisms underlying post-stroke recovery is therefore crucial to find new therapeutic options to address this medical burden. Long-lasting and widespread alterations of γ-aminobutyric acid (GABA) neurotransmission seem to play a key role in stroke recovery. In this review we first discuss a possible model of GABAergic modulation of post-stroke plasticity. We then overview the techniques currently available to non-invasively assess GABA in patients and the conclusions drawn from this limited body of work. Finally, we address the remaining open questions to clarify GABAergic changes underlying post-stroke recovery, we briefly review possible ways to modulate GABA post stroke and propose a novel approach to thoroughly quantify GABA in stroke patients, by integrating its concentration, the activity of its receptors and its link with microstructural changes.

Anti-Neuroinflammatory Effects of the Human Milk Oligosaccharide, 2'-Fucosyllactose, Exerted via Modulation of M2 Microglial Activation in a Mouse Model of Ischemia-Reperfusion Injury

Cerebral ischemic stroke is one of the leading causes of death and disability worldwide. 2'-fucosyllactose (2'-FL), a human milk oligosaccharide, exerts anti-inflammatory effects and plays a protective role in arterial thrombosis; however, its role in ischemic stroke remains unclear. This study aimed to investigate the neuroprotective effects of 2'-FL and its potential mechanisms in a mouse model of ischemic stroke. Neurological score and behavior tests revealed that 2'-FL promoted the recovery of neurological deficits and motor function in middle cerebral artery occlusion (MCAO) mice, and that 2'FL led to a reduction in the size of cerebral infarct. Biochemical studies showed that administration of 2'-FL led to a reduction of reactive oxygen species (ROS)-related products in the brain of MCAO mice. 2'-FL upregulated IL-10 and downregulated TNF-α level. In addition, 2'-FL enhanced M2-type microglial polarization and upregulated CD206 expression at 7 days after MCAO. At 3 days after MCAO, 2'-FL increased IL-4 levels and activated STAT6. Our data show that 2'-FL reduced the neurological symptoms of ischemic stroke and ROS accumulation in the brain through IL-4/STAT6-dependent M2-type microglial polarization in MCAO mice. These results demonstrate that 2'-FL is a potentially effective therapeutic agent for ischemic stroke.

Regulatory mechanisms of natural compounds from traditional Chinese herbal medicines on the microglial response in ischemic stroke

BACKGROUND

Development of clinically effective neuroprotective agents for stroke therapy is still a challenging task. Microglia play a critical role in brain injury and recovery after ischemic stroke. Traditional Chinese herbal medicines (TCHMs) are based on a unique therapeutic principle, have various formulas, and have long been widely used to treat stroke. Therefore, the active compounds in TCHMs and their underlying mechanisms of action are attracting increasing attention in the field of stroke drug development.

PURPOSE

To summarize the regulatory mechanisms of TCHM-derived natural compounds on the microglial response in animal models of ischemic stroke.

METHODS

We searched studies published until 10 April 2023 in the Web of Science, PubMed, and ScienceDirect using the following keywords: natural compounds, natural products or phytochemicals, traditional Chinese Medicine or Chinese herbal medicine, microglia, and ischemic stroke. This review was prepared according to PRISMA (Preferred Reporting Item for Systematic Reviews and Meta-Analysis) guidelines.

RESULTS

Natural compounds derived from TCHMs can attenuate the M1 phenotype of microglia, which is involved in the detrimental inflammatory response, via inhibition of NF-κB, MAPKs, JAK/STAT, Notch, TLR4, P2X7R, CX3CR1, IL-17RA, the NLRP3 inflammasome, and pro-oxidant enzymes. Additionally, the neuroprotective response of microglia with the M2 phenotype can be enhanced by activating Nrf2/HO-1, PI3K/AKT, AMPK, PPARγ, SIRT1, CB2R, TREM2, nAChR, and IL-33/ST2. Several clinical trials showed that TCHM-derived natural compounds that regulate microglial responses have significant and safe therapeutic effects, but further well-designed clinical studies are needed.

CONCLUSIONS

Further research regarding the direct targets and potential pleiotropic or synergistic effects of natural compounds would provide a more reasonable approach for regulation of the microglial response with the possibility of successful stroke drug development.

Heart failure and cognitive impairment: A narrative review of neuroimaging mechanism from the perspective of brain MRI

Both heart failure (HF) and cognitive impairment (CI) have a significant negative impact on the health of the elderly individuals. Magnetic resonance imaging (MRI) can non-invasively detect functional and structural variations in the heart and brain, making it easier to explore the connection between the heart and brain. According to neuroimaging studies, HF patients have a higher chance of developing CI because they have a variety of different types of brain injuries. To examine how HF and CI are influenced by one another, English-language literature was searched in the Web of Science, PubMed EMBASE (OVID), PsycInfo, and Scopus databases. The search terms included “high-frequency,” “brain function,” “brain injury,” “cognition,” “cognitive impairment,” and “magnetic resonance imaging.” Normal brain function is typically impaired by HF in the form of decreased cerebral perfusion pressure, inflammation, oxidative stress, and damage to the BBB, resulting in CI and subsequent HF. Early pathophysiological alterations in patients’ brains have been widely detected using a range of novel MRI techniques, opening up new avenues for investigating the connection between HF and CI. This review aims to describe the pathogenesis of HF with CI and the early diagnostic role of MRI in the heart-brain domain.

Gastrodin and Gastrodigenin Improve Energy Metabolism Disorders and Mitochondrial Dysfunction to Antagonize Vascular Dementia

Vascular dementia (VD) is the second most common dementia syndrome worldwide, and effective treatments are lacking. Gastrodia elata Blume (GEB) has been used in traditional Chinese herbal medicine for centuries to treat cognitive impairment, ischemic stroke, epilepsy, and dizziness. Gastrodin (p-hydroxymethylphenyl-b-D-glucopyranoside, Gas) and Gastrodigenin (p-hydroxybenzyl alcohol, HBA) are the main bioactive components of GEB. This study explored the effects of Gas and HBA on cognitive dysfunction in VD and their possible molecular mechanisms. The VD model was established by bilateral common carotid artery ligation (2-vessel occlusion, 2-VO) combined with an intraperitoneal injection of sodium nitroprusside solution. One week after modeling, Gas (25 and 50 mg/kg, i.g.) and HBA (25 and 50 mg/kg, i.g.) were administered orally for four weeks, and the efficacy was evaluated. A Morris water maze test and passive avoidance test were used to observe their cognitive function, and H&E staining and Nissl staining were used to observe the neuronal morphological changes; the expressions of Aβ1-42 and p-tau396 were detected by immunohistochemistry, and the changes in energy metabolism in the brain tissue of VD rats were analyzed by targeted quantitative metabolomics. Finally, a Hippocampus XF analyzer measured mitochondrial respiration in H2O2-treated HT-22 cells. Our study showed that Gas and HBA attenuated learning memory dysfunction and neuronal damage and reduced the accumulation of Aβ1-42, P-Tau396, and P-Tau217 proteins in the brain tissue. Furthermore, Gas and HBA improved energy metabolism disorders in rats, involving metabolic pathways such as glycolysis, tricarboxylic acid cycle, and the pentose phosphate pathway, and reducing oxidative damage-induced cellular mitochondrial dysfunction. The above results indicated that Gas and HBA may exert neuroprotective effects on VD by regulating energy metabolism and mitochondrial function.

Daidzein Ameliorates Cerebral Ischemic-reperfusion Induced Neuroinflammation in Wistar Rats via Inhibiting NF-κB Signaling Pathway

Background

Cerebral ischemia is a condition of acute brain damage due to the depletion of oxygenated blood supply to cerebral tissues. Daidzein is an isoflavonoid predominantly present in soya, Pueraria species, and red cloves. Traditional Chinese medicine utilizes daidzein to alleviate diseases such as inflammation, hyperglycemia, gastric diseases, allergies and aches. The neuroprotective effect of daidzein on cerebral ischemic conditions and its mechanism of action was not yet elucidated.

Materials and Methods

24 healthy male adult Wistar rats were grouped into four and the control rats were sham-operated, cerebral ischemic-reperfusion induced rats subjected to middle cerebral artery occlusion (MCAO). Low- and high-dose daidzein rats were treated with 25 and 50 mg/kg daidzein respectively for 7 consecutive days before the induction of cerebral ischemic reperfusion. On completion of treatment, the rats were assessed for neurological deficit scoring and then euthanized for further analysis. The percentage of brain water content and cerebral infarct was evaluated. The ability of daidzein on preventing oxidative stress-induced damage was assessed by quantifying lipid peroxidation and antioxidant levels. The neuroprotective Daidzein was evaluated by measuring the acetylcholinesterase activity and brain ATP levels. The anti-inflammatory role of Daidzein was measured by quantifying the nitric oxide (NO) and inflammatory cytokines. Further, the anti-ischemic role of Daidzein was confirmed by estimating nuclear factor-kappa B (NF-κB) p65 and Caspase 3 levels.

Results

Daidzein treatment significantly prevented brain edema and cerebral infarction and neurological deficit in cerebral I/R injured rats. It also scavenged the free radicals and prevented the decline in antioxidant levels of ischemic rats. Daidzein decreased the acetylcholinesterase activity, NO, and inflammatory and significantly increased the brain ATP levels signifying its neuroprotective role in ischemic-induced rats. The reduction in the levels of NF-κB p65 and Caspase 3 confirms daidzein prevents neuroinflammation and neuronal apoptosis in ischemic rats.

Conclusion

Overall our analysis confirms daidzein is a potent neuroprotective drug which can effectively inhibit postischemic complications.

Novel 2,6-disubstituted benzofuran-3-one analogues improve cerebral ischemia/reperfusion injury via neuroprotective and antioxidative effects

There are no highly effective and safe medicines for clinical treatment of ischemic stroke, although the natural product 3-n-butylphthalide (NBP) has been approved in China for mild and moderate ischemic stroke. To discover more potent anti-cerebral ischemic agents and overcome the low stability by phthalide derivatives, benzofuran-3-one was selected as a core moiety and two types of nitric oxide (NO)-donating groups were incorporated into the structure. In this work, a series of 2,6-disubstituted benzofuran-3-one derivatives were designed and synthesised as NBP analogues, and tested as neuroprotective and antioxidative agents. Compounds 5 (without an NO donor) and 16 (with an NO donor) displayed more potent neuroprotective effects than the established clinical drugs Edaravone and NBP. More importantly, 5 and 16 also exhibited good antioxidative activity without cytotoxicity in rat primary neuronal and PC12 cells. Most active compounds showed good blood-brain barrier permeability in a parallel artificial membrane permeability assay. Furthermore, compound 5 reduced the ischemic infarct area significantly in rats subjected to ischemia/reperfusion injury, downregulated ionised calcium-binding adaptor molecule 1 and glial fibrillary acidic protein in inflammatory cells, and upregulated nerve growth factor.

Elabela-APJ axis attenuates cerebral ischemia/reperfusion injury by inhibiting neuronal ferroptosis

Ferroptosis is a form of non-apoptotic cell death caused by iron-dependent peroxidation of lipids. It contributes to ischemic stroke-induced neuronal damage. Elabela (ELA), a novel endogenous ligand for Apelin receptor (APJ), regulates oxidative stress and exerts a protective role in cardiovascular disease. However, the effect of ELA-APJ axis on cellular ferroptosis in cerebral ischemia/reperfusion (I/R) remains elusive. The present study showed that ELA and APJ were expressed on neurons and increased after cerebral I/R injury. The I/R insult triggered typical molecular and morphological features of neuronal ferroptosis, including iron and MDA accumulation, mitochondrial shrink and membrane rupture, upregulation of positive ferroptosis regulators and downregulation of negative regulators. ELA-32 treatment reduced brain infarction and ameliorated neurobehavioral deficits and cognitive dysfunction. Moreover, ELA-32 administration alleviated neuronal ferroptosis, accompanied by reduced iron deposition, decreased mitochondrial damage, relived lipid peroxidation and glutathione reduction. Such effects of ELA-32 were abolished by AAV-APJ-RNAi or nuclear factor erythroid 2-related factor 2 (NRF2) inhibitor ML385. Mechanistically, ELA was shown to bind to APJ and activate NRF2/ARE anti-oxidative signaling pathway via Gα13. Together, these findings suggested that ELA-APJ axis mitigates neuronal ferroptosis after ischemic stroke and that the ELA-32 peptide may be a putative therapeutic avenue for ischemic stroke.

Ischemic Stroke Causes Disruptions in the Carnitine Shuttle System

Gaining a deep understanding of the molecular mechanisms underlying ischemic stroke is necessary to develop treatment alternatives. Ischemic stroke is known to cause a cellular energy imbalance when glucose supply is deprived, enhancing the role for energy production via β-oxidation where acylcarnitines are essential for the transportation of fatty acids into the mitochondria. Although traditional bulk analysis methods enable sensitive detection of acylcarnitines, they do not provide information on their abundances in various tissue regions. However, with quantitative mass spectrometry imaging the detected concentrations and spatial distributions of endogenous molecules can be readily obtained in an unbiased way. Here, we use pneumatically assisted nanospray desorption electrospray ionization mass spectrometry imaging (PA nano-DESI MSI) doped with internal standards to study the distributions of acylcarnitines in mouse brain affected by stroke. The internal standards enable quantitative imaging and annotation of endogenous acylcarnitines is achieved by studying fragmentation patterns. We report a significant accumulation of long-chain acylcarnitines due to ischemia in brain tissue of the middle cerebral artery occlusion (MCAO) stroke model. Further, we estimate activities of carnitine transporting enzymes and demonstrate disruptions in the carnitine shuttle system that affects the β-oxidation in the mitochondria. Our results show the importance for quantitative monitoring of metabolite distributions in distinct tissue regions to understand cell compensation mechanisms involved in handling damage caused by stroke.

Imaging of glutamate in acute carbon monoxide poisoning using chemical exchange saturation transfer

Aims

This study adopted the Glutamate Chemical Exchange Saturation Transfer (GluCEST) imaging technique to quantitatively analyze cranial glutamate and discussed the effectiveness of GluCEST values in identifying the pathogenesis of encephalopathy after CO poisoning.

Methods

The routine MRI and functional MRI scans of two cohorts of subjects (CO group, n = 29; Control group, n = 21) were performed. Between-group comparisons were conducted for GluCEST% in regions of interest (ROI), including the basal ganglia, the thalamus, the frontal lobe, the occipital lobe, the genu of corpus callosum, the cingulate gyrus, and the cuneus. Moreover, an age-stratified subgroup analysis was devised, and a correlational analysis was performed for GluCEST% in each ROI, including the time in coma, Simple Mini-Mental State Examination Scale (MMSE) score, Hamilton Anxiety Scale score, and blood COHb%.

Results

As compared to the healthy control, the CO group led to significantly increasing GluCEST% in the basal ganglia, the occipital lobe, the genu of the corpus callosum, the cingulate gyrus, and the cuneus (p < 0.05). In the subgroup analysis for age, adult patients had higher GluCEST% in the basal ganglia, the thalamus, the occipital lobe, the cingulate gyrus, and the cuneus compared to healthy adults (p < 0.05). In addition, the correlational analysis of CO-poisoned patients revealed a statistical association between the GluCEST% and the MMSE in the thalamus and the genu of the corpus callosum.

Conclusion

The GluCEST technique is superior to routine MRI in that it can identify the cerebral biochemical changes sooner after acute CO poisoning, which is significant for our understanding of the role of neurotransmitters in the pathological basis of this disease. Brain injury caused by CO poisoning may be different in adults and children.

Machine Learning Analysis of the Cerebrovascular Thrombi Lipidome in Acute Ischemic Stroke

ABSTRACT

OBJECTIVE: The aim of this study was to identify a signature lipid profile from cerebral thrombi in acute ischemic stroke (AIS) patients at the time of ictus. METHODS: We performed untargeted lipidomics analysis using liquid chromatography-mass spectrometry on cerebral thrombi taken from a nonprobability, convenience sampling of adult subjects (≥18 years old, n = 5) who underwent thrombectomy for acute cerebrovascular occlusion. The data were classified using random forest, a machine learning algorithm. RESULTS: The top 10 metabolites identified from the random forest analysis were of the glycerophospholipid species and fatty acids. CONCLUSION: Preliminary analysis demonstrates feasibility of identification of lipid metabolomic profiling in cerebral thrombi retrieved from AIS patients. Recent advances in omic methodologies enable lipidomic profiling, which may provide insight into the cellular metabolic pathophysiology caused by AIS. Understanding of lipidomic changes in AIS may illuminate specific metabolite and lipid pathways involved and further the potential to develop personalized preventive strategies.

The role of neurophysiological tools in the evaluation of ischemic stroke evolution: a narrative review

Ischemic stroke is characterized by a complex cascade of events starting from vessel occlusion. The term "penumbra" denotes the area of severely hypo-perfused brain tissue surrounding the ischemic core that can be potentially recovered if blood flow is reestablished. From the neurophysiological perspective, there are local alterations-reflecting the loss of function of the core and the penumbra-and widespread changes in neural networks functioning, since structural and functional connectivity is disrupted. These dynamic changes are closely related to blood flow in the affected area. However, the pathological process of stroke does not end after the acute phase, but it determines a long-term cascade of events, including changes of cortical excitability, that are quite precocious and might precede clinical evolution. Neurophysiological tools-such as Transcranial Magnetic Stimulation (TMS) or Electroencephalography (EEG)-have enough time resolution to efficiently reflect the pathological changes occurring after stroke. Even if they do not have a role in acute stroke management, EEG and TMS might be helpful for monitoring ischemia evolution-also in the sub-acute and chronic stages. The present review aims to describe the changes occurring in the infarcted area after stroke from the neurophysiological perspective, starting from the acute to the chronic phase.

The α2δ-1-NMDA receptor complex and its potential as a therapeutic target for ischemic stroke

N-methyl-_D-aspartate receptors (NMDARs) play a critical role in excitotoxicity caused by ischemic stroke, but NMDAR antagonists have failed to be translated into clinical practice for treating stroke patients. Recent studies suggest that targeting the specific protein-protein interactions that regulate NMDARs may be an effective strategy to reduce excitotoxicity associated with brain ischemia. α2δ-1 (encoded by the Cacna2d1 gene), previously known as a subunit of voltage-gated calcium channels, is a binding protein of gabapentinoids used clinically for treating chronic neuropathic pain and epilepsy. Recent studies indicate that α2δ-1 is an interacting protein of NMDARs and can promote synaptic trafficking and hyperactivity of NMDARs in neuropathic pain conditions. In this review, we highlight the newly identified roles of α2δ-1-mediated NMDAR activity in the gabapentinoid effects and NMDAR excitotoxicity during brain ischemia as well as targeting α2δ-1-bound NMDARs as a potential treatment for ischemic stroke.

Neuroprotective Strategies for Stroke by Natural Products: Advances and Perspectives

Cerebral ischemic stroke is a disease with high prevalence and incidence. Its management focuses on rapid reperfusion with intravenous thrombolysis and endovascular thrombectomy. Both therapeutic strategies reduce disability, but the therapy time window is short, and the risk of bleeding is high. Natural products (NPs) have played a key role in drug discovery, especially for cancer and infectious diseases. However, they have made little progress in clinical translation and pose challenges to the treatment of stroke. Recently, with the investigation of precise mechanisms in cerebral ischemic stroke and the technological development of NP-based drug discovery, NPs are addressing these challenges and opening up new opportunities in cerebral stroke. Thus, in this review, we first summarize the structure and function of diverse NPs, including flavonoids, phenols, terpenes, lactones, quinones, alkaloids, and glycosides. Then we propose the comprehensive neuroprotective mechanism of NPs in cerebral ischemic stroke, which involves complex cascade processes of oxidative stress, mitochondrial damage, apoptosis or ferroptosis-related cell death, inflammatory response, and disruption of the blood-brain barrier (BBB). Overall, we stress the neuroprotective effect of NPs and their mechanism on cerebral ischemic stroke for a better understanding of the advances and perspective in NPs application that may provide a rationale for the development of innovative therapeutic regimens in ischemic stroke.

The Therapeutic Potential of Mitochondria Transplantation Therapy in Neurodegenerative and Neurovascular Disorders

Neurodegenerative and neurovascular disorders affect millions of people worldwide and account for a large and increasing health burden on the general population. Thus, there is a critical need to identify potential disease-modifying treatments that can prevent or slow the disease progression. Mitochondria are highly dynamic organelles and play an important role in energy metabolism and redox homeostasis, and mitochondrial dysfunction threatens cell homeostasis, perturbs energy production, and ultimately leads to cell death and diseases. Impaired mitochondrial function has been linked to the pathogenesis of several human neurological disorders. Given the significant contribution of mitochondrial dysfunction in neurological disorders, there has been considerable interest in developing therapies that can attenuate mitochondrial abnormalities and proffer neuroprotective effects. Unfortunately, therapies that target specific components of mitochondria or oxidative stress pathways have exhibited limited translatability. To this end, mitochondrial transplantation therapy (MTT) presents a new paradigm of therapeutic intervention, which involves the supplementation of healthy mitochondria to replace the damaged mitochondria for the treatment of neurological disorders. Prior studies demonstrated that the supplementation of healthy donor mitochondria to damaged neurons promotes neuronal viability, activity, and neurite growth and has been shown to provide benefits for neural and extra-neural diseases. In this review, we discuss the significance of mitochondria and summarize an overview of the recent advances and development of MTT in neurodegenerative and neurovascular disorders, particularly Parkinson's disease, Alzheimer's disease, and stroke. The significance of MTT is emerging as they meet a critical need to develop a diseasemodifying intervention for neurodegenerative and neurovascular disorders.

Investigation of therapeutic effects of calcium dobesilate in cerebral hypoxia/ reperfusion injury in rats

OBJECTIVES

Cerebral stroke is a serious clinical condition in which oxidative stress, inflammation, necrosis, apoptosis, and autophagy play important roles in its pathogenesis. This study investigated the neuroprotective and healing effects of calcium dobesilate (CD) on cerebral hypoxia/reperfusion injury in rats.

METHODS

Forty Wistar albino male rats, each weighing 300-350 g, were separated into the Control group (no surgery and no pharmacological agent was administered); Sham-A group (only surgery was performed); DBL-A group (surgery was performed and CD 100 mg/kg/day was administered intraperitoneally for 3 days); Sham-C group (only surgery was performed); and DBL-C group (surgery was performed and 100 mg/kg/day CD was administered intraperitoneally for 10 days). Under sedation anesthesia, the bilateral common carotid arteries of all rats except the Control group were clipped for 30 min. After 4 h, the CD was given to the relevant groups, and then, all subjects were euthanized at scheduled times. The brain of each animal was removed for histopathological (hematoxylin and eosin staining), immunohistochemical (beclin-1, anti-MHC class II and anti-CD-68 staining), and biochemical (TNF, IL-1β, IL-6, caspase-3, GSH/GSSG, malondialdehyde, protein carbonyl, LC3II/LC3I, and beclin-1 levels) evaluations.

RESULTS

It was observed that CD could reduce necrosis and mitigate polarization of microglia to the M1 phenotype, autophagy, free oxygen radicals, protein carbonylation, lipid peroxidation, IL-1β, IL6, TNF, caspase-3, beclin-1, and LC3II/LC3I levels in acute and chronic periods of hypoxia/reperfusion injury.

CONCLUSION

From these results, it was observed that CD treatment could reduce neuronal necrosis and create anti-inflammatory, anti-edema, anti-oxidant, anti-apoptotic, and anti-autophagic effects in hypoxia/reperfusion injury in rats.

CaMKIIα as a Promising Drug Target for Ischemic Grey Matter

Ca2+/calmodulin-dependent protein kinase II (CaMKII) is a major mediator of Ca2+-dependent signaling pathways in various cell types throughout the body. Its neuronal isoform CaMKIIα (alpha) centrally integrates physiological but also pathological glutamate signals directly downstream of glutamate receptors and has thus emerged as a target for ischemic stroke. Previous studies provided evidence for the involvement of CaMKII activity in ischemic cell death by showing that CaMKII inhibition affords substantial neuroprotection. However, broad inhibition of this central kinase is challenging because various essential physiological processes like synaptic plasticity rely on intact CaMKII regulation. Thus, specific strategies for targeting CaMKII after ischemia are warranted which would ideally only interfere with pathological activity of CaMKII. This review highlights recent advances in the understanding of how ischemia affects CaMKII and how pathospecific pharmacological targeting of CaMKII signaling could be achieved. Specifically, we discuss direct targeting of CaMKII kinase activity with peptide inhibitors versus indirect targeting of the association (hub) domain of CaMKIIα with analogues of γ-hydroxybutyrate (GHB) as a potential way to achieve more specific pharmacological modulation of CaMKII activity after ischemia.

Pre-treatment or post-treatment with hydroxychloroquine demonstrates neuroprotective effects in cerebral ischemia/reperfusion

Stroke is a serious life-threatening medical condition and is one of the principal reasons for death and disabilities worldwide. The aim of the present study was to determine the neuroprotective effects of hydroxychloroquine (HCQ) and the timing of its administration in cerebral ischemia/reperfusion (I/R) in rats. A global I/R model was used, and HCQ was administered in either pre- or post-treatment doses of 25 and 50 mg/kg. Effects of HCQ on infarct size, histological changes, oxidative stress, and learning and memory were evaluated. Phospho-AMPK and SQSTM1/p62 protein levels were also measured to elucidate the possible mechanisms involved. HCQ in both pre- (at doses of 25 and 50 mg/kg) or post-treatment (at a dose of 50 mg/kg) protocols reduces brain infarct size and histopathological changes and improves learning and memory after cerebral I/R. Pre-treatment with HCQ reduced AMPK activity with no significant effect on SQSTM1/p62 increment. Post-treatment with HCQ increased AMPK activity and SQSTM1/p62 protein levels. Our results show the neuroprotective effects of HCQ on cerebral I/R through the reduction in infarct size, histopathological changes, and improvement in memory and learning functions. Moreover, AMPK and autophagy may play a role in this protective effect.

Roles of glutamate in brain injuries after subarachnoid hemorrhage

Aneurysmal subarachnoid hemorrhage (SAH) is a stroke type with a high rate of mortality and morbidity. Post-SAH brain injury as a determinant of poor outcome is classified into the following two types: early brain injury (EBI) and delayed cerebral ischemia (DCI). EBI consists of various acute brain pathophysiologies that occur within the first 72 hours of SAH in a clinical setting. The underlying mechanisms of DCI are considered to be cerebral vasospasm or microcirculatory disturbance, which develops mostly 4 to 14 days after clinical SAH. Glutamate is the principal neurotransmitter in the central nervous system, but excessive glutamate is known to induce neurotoxicity. Experimental and clinical studies have revealed that excessive glutamates are released after SAH. In addition, many studies have reported the relationships between excessive glutamate release or overactivation of glutamate receptors and excitotoxicity, cortical spreading depolarization, seizure, increased blood-brain barrier permeability, neuroinflammation, microthrombosis formation, microvasospasm, cerebral vasospasm, impairments of brain metabolic supply and demand, impaired neurovascular coupling, and so on, all of which potentially contribute to the development of EBI or DCI. As glutamates always exert their functions through one or more of 4 major receptors of glutamates, it would be valuable to know the mechanisms as to how glutamates cause these pathologies, and the possibility that a glutamate receptor antagonist may block the pathologies. To prevent the mechanistic steps leading to glutamate-mediated neurotoxicity may ameliorate SAH-induced brain injuries and improve the outcomes. This review addresses the current knowledge of glutamate-mediated neurotoxicity, focusing on EBI and DCI after SAH.

An Intelligent Motor Assessment Method Utilizing a Bi-Lateral Virtual-Reality Task for Stroke Rehabilitation on Upper Extremity

Virtual reality (VR) has been widely adopted by therapists to provide rich motor training tasks. Time series data of motion trajectory accompanied with the interaction of VR system may contain important clues in regard to the assessment of motor function, however, clinical evaluation scales such as Fugl-Meyer Assessment (FMA), Wolf Motor Function Test (WMFT), and Test D'évaluation Des Membres Supérieurs Des Personnes Âgées (TEMPA) are highly depended in clinic. Further, there is not yet an assessment method that simultaneously consider motion trajectory and clinical evaluation scales. The objective of this study is to establish an evidence-based assessment model by machine-learning method that integrated motion trajectory of a VR task with clinical evaluation scales. In this study, a VR system for upper-limb motor training was proposed for stroke rehabilitation. Clinical trials with 20 stroke patients were performed. A variety of motor indicators that derived via motion trajectory were proposed. The correlations between motor indicators and clinical evaluation scales were examined. Further, motor indicators were integrated with evaluation scales to develop a machine-learning based model that represents an evidence-based motor assessment approach. Clinical evaluation scales, FMA, TEMPA and WMFT, were significantly progressed. A few motor indicators were found significantly correlated with clinical evaluation scales. The accuracy of machine-learning based assessment model was up to 86%. The proposed VR system is validated to be effective in motor rehabilitation. Motor indicators derived from motor trajectory were with potential for clinical motor assessment. Machine learning could be a promising tool to perform automatic assessment. Clinical and Translational Impact Statement-A VR task for motor rehabilitation was exanimated via clinical trials. Integrating motor indices with clinical assessment, a machine-learning model with accuracy of 86% was developed to evaluate motor function.