Anti-Inflammatory Targets for the Treatment of Reperfusion Injury in Stroke

Exosomes: the next-generation therapeutic platform for ischemic stroke

Current therapeutic strategies for ischemic stroke fall short of the desired objective of neurological functional recovery. Therefore, there is an urgent need to develop new methods for the treatment of this condition. Exosomes are natural cell-derived vesicles that mediate signal transduction between cells under physiological and pathological conditions. They have low immunogenicity, good stability, high delivery efficiency, and the ability to cross the blood-brain barrier. These physiological properties of exosomes have the potential to lead to new breakthroughs in the treatment of ischemic stroke. The rapid development of nanotechnology has advanced the application of engineered exosomes, which can effectively improve targeting ability, enhance therapeutic efficacy, and minimize the dosages needed. Advances in technology have also driven clinical translational research on exosomes. In this review, we describe the therapeutic effects of exosomes and their positive roles in current treatment strategies for ischemic stroke, including their anti-inflammation, anti-apoptosis, autophagy-regulation, angiogenesis, neurogenesis, and glial scar formation reduction effects. However, it is worth noting that, despite their significant therapeutic potential, there remains a dearth of standardized characterization methods and efficient isolation techniques capable of producing highly purified exosomes. Future optimization strategies should prioritize the exploration of suitable isolation techniques and the establishment of unified workflows to effectively harness exosomes for diagnostic or therapeutic applications in ischemic stroke. Ultimately, our review aims to summarize our understanding of exosome-based treatment prospects in ischemic stroke and foster innovative ideas for the development of exosome-based therapies.

Metformin ameliorates neuroinflammatory environment for neurons and astrocytes during in vitro and in vivo stroke and tobacco smoke chemical exposure: Role of Nrf2 activation

Despite the protective nature of the blood-brain barrier (BBB) and brain-protecting tissues, some types of CNS injury or stress can cause cerebral cytokine production and profound alterations in brain function. Neuroinflammation, which can also be accompanied by increased cerebral cytokine production, has a remarkable impact on the pathogenesis of many neurological illnesses, including loss of BBB integrity and ischemic stroke, yet effective treatment choices for these diseases are currently lacking. Although little is known about the brain effects of Metformin (MF), a commonly prescribed first-line antidiabetic drug, prior research suggested that it may be useful in preventing BBB deterioration and the increased risk of stroke caused by tobacco smoking (TS). Therefore, reducing neuroinflammation by escalating anti-inflammatory cytokine production and declining pro-inflammatory cytokine production could prove an effective therapeutic strategy for ischemic stroke. Hence, the current investigation was planned to explore the potential role of MF against stroke and TS-induced neuroinflammation and reactive oxygen species (ROS) production. Our studies revealed that MF suppressed releasing pro-inflammatory mediators like tumor necrosis factor-α (TNF-α) and interleukin-1β (IL-1β) by aiming at the nuclear factor kappa B (NF-κB) signaling pathway in primary neurons and astrocytes. MF also upregulated anti-inflammatory mediators, like interleukin-10 (IL-10), and interleukin-4 (IL-4), by upregulating the Nrf2-ARE signaling pathway. Adolescent mice receiving MF along with TS exposure also showed a notable decrease in NF-κB expression compared to the mice not treated with MF and significantly decreased the level of TNF-α, IL-1β, MCP-1, and MIP-2 and increased the levels of IL-10 and IL-4 through the activation of Nrf2-ARE signaling pathway. These results suggest that MF has anti-neuroinflammatory effects via inhibiting NF-κB signaling by activating Nrf2-ARE. These studies support that MF could be a strong candidate drug for treating and or preventing TS-induced neuroinflammation and ischemic stroke.

Mitochondrial mechanisms in Cerebral Ischemia-Reperfusion Injury: Unravelling the intricacies

Cerebral ischemic stroke is a major contributor to physical impairments and premature death worldwide. The available reperfusion therapies for stroke in the form of mechanical thrombectomy and intravenous thrombolysis increase the risk of cerebral ischemia-reperfusion (I-R) injury due to sudden restoration of blood supply to the ischemic region. The injury is manifested by hemorrhagic transformation, worsening of neurological impairments, cerebral edema, and progression to infarction in surviving patients. A complex network of multiple pathological processes has been known to be involved in the pathogenesis of I-R injury. Primarily, 3 major contributors namely oxidative stress, neuroinflammation, and mitochondrial failure have been well studied in I-R injury. A transcription factor, Nrf2 (Nuclear factor erythroid 2-related factor 2) plays a crucial defensive role in resisting the deleterious effects of I-R injury and potentiating the cellular protective mechanisms. In this review, we delve into the critical function of mitochondria and Nrf2 in the context of cerebral I-R injury. We summarized how oxidative stress, neuroinflammation, and mitochondrial anomaly contribute to the pathophysiology of I-R injury and further elaborated the role of Nrf2 as a pivotal guardian of cellular integrity. The review further highlighted Nrf2 as a putative therapeutic target for mitochondrial dysfunction in cerebral I-R injury management.

Forsythoside B alleviates cerebral ischemia-reperfusion injury via inhibiting NLRP3 inflammasome mediated by SIRT1 activation

BACKGROUND

The inflammatory response is a key factor in the pathogenesis of cerebral ischemia/reperfusion injury (CIRI), and anti-inflammatory interventions may offer a promising therapeutic strategy. Forsythoside B (FB) is a phenylethanoid glycoside isolated from Forsythiae fructus, which has been reported to have anti-inflammatory effects. However, the mechanism of the neuroprotective effect of FB on CIRI remains unclear.

METHODS

Adult male Sprague-Dawley rats were subjected to transient middle cerebral artery occlusion/reperfusion (MCAO/R). FB was administered intraperitoneally for 3 days prior to MCAO/R. Cerebral infarct volume and neurological deficit score were used as indices to evaluate MCAO/R injury. The serum levels of inflammatory factors and antioxidant enzymes were measured. The activation of silent information regulator 2 homolog 1 (Sirt1) and the inhibition of the nucleotide-binding oligomerization domain-like receptor with a pyrin domain 3 (NLRP3) pathway were assessed through western blot and immunohistochemistry analysis. Furthermore, the rats were treated with Sirt1 shRNA 3 days before MCAO/R by stereotactical injection into the ipsilateral hemispheric region to assess the impact of Sirt1 knockdown on the protection of FB during MCAO/R.

RESULTS

FB reduced cerebral infarct volume and neurological deficit score in MCAO/R rats. FB reduced pathological changes and cell apoptosis in the hippocampal CA1 region and cortex on the ischemic side of rats. FB inhibited the serum levels of inflammatory factors and increased the activities of antioxidant enzymes. Further study showed that FB inhibited the activation of the NLRP3 pathway and induced Sirt1 activation.

CONCLUSION

FB demonstrated neuroprotective and anti-inflammatory effects by inhibiting the NLRP3 pathway through Sirt1 activation in CIRI.

Advances in Engineered Nanoparticles for the Treatment of Ischemic Stroke by Enhancing Angiogenesis

Angiogenesis, or the formation of new blood vessels, is a natural defensive mechanism that aids in the restoration of oxygen and nutrition delivery to injured brain tissue after an ischemic stroke. Angiogenesis, by increasing vessel development, may maintain brain perfusion, enabling neuronal survival, brain plasticity, and neurologic recovery. Induction of angiogenesis and the formation of new vessels aid in neurorepair processes such as neurogenesis and synaptogenesis. Advanced nano drug delivery systems hold promise for treatment stroke by facilitating efficient transportation across the the blood-brain barrier and maintaining optimal drug concentrations. Nanoparticle has recently been shown to greatly boost angiogenesis and decrease vascular permeability, as well as improve neuroplasticity and neurological recovery after ischemic stroke. We describe current breakthroughs in the development of nanoparticle-based treatments for better angiogenesis therapy for ischemic stroke employing polymeric nanoparticles, liposomes, inorganic nanoparticles, and biomimetic nanoparticles in this study. We outline new nanoparticles in detail, review the hurdles and strategies for conveying nanoparticle to lesions, and demonstrate the most recent advances in nanoparticle in angiogenesis for stroke treatment.

MMP-9 upregulation may predict hemorrhagic transformation after endovascular thrombectomy

Background

Hemorrhagic transformation (HT) is a serious complication after endovascular thrombectomy (EVT) for patients with acute ischemic stroke (AIS). We analyzed the plasma levels of MMP-9 before and after EVT and assessed the temporal changes of MMP-9 that may be associated with, and therefore predict, HT after EVT.

Methods

We enrolled 30 AIS patients who received EVT, and 16 (53.3%) developed HT. The levels of MMP-9 in plasma collected from the arteries of AIS patients before and immediately after EVT were measured using ELISA. The percent change in MMP-9 after EVT (after/before) was calculated and compared between patients with and without HT.

Results

The median age of the AIS patients was 70 years, and 13 patients (43.3%) were men. The median National Institutes of Health Stroke Scale (NIHSS) scores of patients with HT were 18 on admission and 18 after EVT. The median NIHSS scores of patients without HT were 17 on admission and 11 after EVT. Patients with HT demonstrated significantly greater percentage increases in arterial MMP-9 levels after EVT.

Conclusion

Patients with AIS who developed HT had significantly increased arterial MMP-9 levels after EVT, suggesting that the upregulation of MMP-9 following EVT could serve as a predictive biomarker for HT.

Integrated transcriptomic and proteomic profiling reveals the key molecular signatures of brain endothelial reperfusion injury

BACKGROUND

Reperfusion therapy after ischemic stroke often causes brain microvascular injury. However, the underlying mechanisms are unclear.

METHODS

Transcriptomic and proteomic analyses were performed on human cerebral microvascular endothelial cells following oxygen-glucose deprivation (OGD) or OGD plus recovery (OGD/R) to identify molecules and signaling pathways dysregulated by reperfusion. Major findings were further validated in a mouse model of cerebral ischemia and reperfusion.

RESULTS

Transcriptomic analysis identified 390 differentially expressed genes (DEGs) between the OGD/R and OGD group. Pathway analysis indicated that these genes were mostly associated with inflammation, including the TNF signaling pathway, TGF-β signaling pathway, cytokine-cytokine receptor interaction, NOD-like receptor signaling pathway, and NF-κB signaling pathway. Proteomic analysis identified 201 differentially expressed proteins (DEPs), which were primarily associated with extracellular matrix destruction and remodeling, impairment of endothelial transport function, and inflammatory responses. Six genes (DUSP1, JUNB, NFKBIA, NR4A1, SERPINE1, and THBS1) were upregulated by OGD/R at both the mRNA and protein levels. In mice with cerebral ischemia and reperfusion, brain TNF signaling pathway was activated by reperfusion, and inhibiting TNF-α with adalimumab significantly attenuated reperfusion-induced brain endothelial inflammation. In addition, the protein level of THBS1 was substantially upregulated upon reperfusion in brain endothelial cells and the peri-endothelial area in mice receiving cerebral ischemia.

CONCLUSION

Our study reveals the key molecular signatures of brain endothelial reperfusion injury and provides potential therapeutic targets for the treatment of brain microvascular injury after reperfusion therapy in ischemic stroke.

Serum from Stroke Patients with High-Grade Carotid Stenosis Promotes Cyclooxygenase-Dependent Endothelial Dysfunction in Non-ischemic Mice Carotid Arteries

Atherosclerosis is responsible for 20% of ischemic strokes, and severe carotid stenosis is associated with a higher incidence of first-ever and recurrent strokes. The release of pro-inflammatory mediators into the blood in severe atherosclerosis may aggravate endothelial dysfunction after stroke contributing to impair disease outcomes. We hypothesize that environments of severe carotid atherosclerotic disease worsen endothelial dysfunction in stroke linked to enhanced risk of further cerebrovascular events. We mounted nonischemic common carotid arteries from 2- to 4-month-old male Oncins France 1 mice in tissue baths for isometric contraction force measurements and exposed them to serum from men with a recent ischemic stroke and different degrees of carotid stenosis: low- or moderate-grade stenosis (LMGS; < 70%) and high-grade stenosis (HGS; ≥ 70%). The results show that serum from stroke patients induced an impairment of acetylcholine relaxations in mice carotid arteries indicative of endothelium dysfunction. This effect was more pronounced after incubation with serum from patients with a recurrent stroke or vascular death within 1 year of follow-up. When patients were stratified according to the degree of stenosis, serum from HGS patients induced more pronounced carotid artery endothelial dysfunction, an effect that was associated with enhanced circulating levels of IL-1β. Mechanistically, endothelial dysfunction was prevented by both nonselective and selective COX blockade. Altogether, the present findings add knowledge on the understanding of the mechanisms involved in the increased risk of stroke in atherosclerosis and suggest that targeting COX in the carotid artery wall may represent a potential novel therapeutic strategy for secondary stroke prevention.

Transcutaneous electrical acupoint stimulation alleviates cerebral ischemic injury through the TLR4/MyD88/NF-κ B pathway

This study was to explore whether transcutaneous electrical acupoint stimulation (TEAS) treatment could mediate inflammation, apoptosis, and pyroptosis of neuronal cells and microglia activation through the TLR4/MyD88/NF-κB pathway in the early stage of ischemic stroke. TEAS treatment at Baihui (GV20) and Hegu (LI4) acupoints of the affected limb was administered at 24, 48, and 72 h following middle cerebral artery occlusion/reperfusion (MCAO/R), with lasting for 30 min each time. Neurological impairment scores were assessed 2 h and 72 h after ischemia/reperfusion (I/R). TTC staining was used to evaluate the volume of brain infarction. The histopathologic changes of hippocampus were detected by H&E staining. WB analysis was performed to assess the levels of TLR4, MyD88, p-NF-κB p65/NF-κB p65, and inflammation, apoptosis, pyroptosis-related proteins. TLR4 expression was measured using immunohistochemistry. The expression of inflammation-related proteins was also measured using ELISA. Immunofluorescence was used to detect the expression level of Iba1. Our findings demonstrated that TEAS intervention after I/R improved neurological function, reduced the volume of brain infarction, and mitigated pathological damage. Moreover, TEAS reduced the levels of TLR4, MyD88, p-NF-κB p65/NF-κB p65, TNF-α, IL-6, Bax, NLRP3, cleaved caspase-1/pro caspase-1, IL-1β, IL-18, GSDMD, and Iba1 while enhancing Bcl-2 expression. Moreover, the protective effects of TEAS could be counteracted by lipopolysaccharide (LPS, a TLR4 agonist). In conclusion, TEAS can reduce cerebral damage and suppress inflammation, cell death, and microglia activation after ischemic stroke via inhibiting the TLR4/MyD88/NF-κB pathway.

Role of Lipocalin-2 in N1/N2 Neutrophil Polarization After Stroke

BACKGROUND

Neutrophils and Lipocalin-2 (LCN2) play pivotal roles in cerebral ischemiareperfusion (I/R) injury. However, their contribution is not fully clarified.

OBJECTIVE

This study aimed to explore the role of LCN2 and its association with neutrophil polarization in I/R injury.

METHODS

A mouse model of middle cerebral artery occlusion (MCAO) was used to induce cerebral ischemia. LCN2mAb was administered 1 h and Anti-Ly6G was administered for 3d before MCAO. The role of LCN2 in the polarity transition of neutrophils was explored using an in vitro HL-60 cell model.

RESULTS

LCN2mAb pretreatment had neuroprotective effects in mice. The expression of Ly6G was not significantly different, but the expression of N2 neutrophils was increased. In the in vitro study, LCN2mAb-treated N1-HL-60 cells induced N2-HL-60 polarization.

CONCLUSION

LCN2 may affect the prognosis of ischemic stroke by mediating neutrophil polarization.

Investigating the Potential Mechanisms and Therapeutic Targets of Inflammatory Cytokines in Post-stroke Depression

Post-stroke depression (PSD) affects approximately one-third of stroke survivors, severely impacting general recovery and quality of life. Despite extensive studies, the exact mechanisms underlying PSD remain elusive. However, emerging evidence implicates proinflammatory cytokines, including interleukin-1β, interleukin-6, tumor necrosis factor-alpha, and interleukin-18, play critical roles in PSD development. These cytokines contribute to PSD through various mechanisms, including hypothalamic-pituitary-adrenal (HPA) axis dysfunction, neurotransmitter alterations, neurotrophic factor changes, gut microbiota imbalances, and genetic predispositions. This review is aimed at exploring the role of cytokines in stroke and PSD while identifying their potential as specific therapeutic targets for managing PSD. A more profound understanding of the mechanisms regulating inflammatory cytokine expression and anti-inflammatory cytokines like interleukin-10 in PSD may facilitate the development of innovative interventions to improve outcomes for stroke survivors experiencing depression.

Lost in Translation: Neurotrophins Biology and Function in the Neurovascular Unit

The neurovascular unit (NVU) refers to the functional building unit of the brain and the retina, where neurons, glia, and microvasculature orchestrate to meet the demand of the retina's and brain's function. Neurotrophins (NTs) are structural families of secreted proteins and are known for exerting neurotrophic effects on neuronal differentiation, survival, neurite outgrowth, synaptic formation, and plasticity. NTs include several molecules, such as nerve growth factor, brain-derived neurotrophic factor, NT-3, NT-4, and their precursors. Furthermore, NTs are involved in signaling pathways such as inflammation, apoptosis, and angiogenesis in a nonneuronal cell type. Interestingly, NTs and the precursors can bind and activate the p75 neurotrophin receptor (p75NTR) at low and high affinity. Mature NTs bind their cognate tropomyosin/tyrosine-regulated kinase receptors, crucial for maintenance and neuronal development in the brain and retina axis. Activation of p75NTR results in neuronal apoptosis and cell death, while tropomysin receptor kinase upregulation contributes to differentiation and cell growth. Recent findings indicate that modulation of NTs and their receptors contribute to neurovascular dysfunction in the NVU. Several chronic metabolic and acute ischemic diseases affect the NVU, including diabetic and ischemic retinopathy for the retina, as well as stroke, acute encephalitis, and traumatic brain injury for the brain. This work aims to review the current evidence through published literature studying the impact of NTs and their receptors, including the p75NTR receptor, on the injured and healthy brain-retina axis.

Contribution and therapeutic value of mitophagy in cerebral ischemia-reperfusion injury after cardiac arrest

Cardiopulmonary resuscitation and related life support technologies have improved substantially in recent years; however, mortality and disability rates from cardiac arrest (CA) remain high and are closely associated with the high incidence of cerebral ischemia-reperfusion injury (CIRI), which is explained by a "double-hit" model (i.e., resulting from both ischemia and reperfusion). Mitochondria are important power plants in the cell and participate in various biochemical processes, such as cell differentiation and signaling in eukaryotes. Various mitochondrial processes, including energy metabolism, calcium homeostasis, free radical production, and apoptosis, are involved in several important stages of the progression and development of CIRI. Mitophagy is a key mechanism of the endogenous removal of damaged mitochondria to maintain organelle function and is a critical target for CIRI treatment after CA. Mitophagy also plays an essential role in attenuating ischemia-reperfusion in other organs, particularly during post-cardiac arrest myocardial dysfunction. Regulation of mitophagy may influence necroptosis (a programmed cell death pathway), which is the main endpoint of organ ischemia-reperfusion injury. In this review, we summarize the main signaling pathways related to mitophagy and their associated regulatory proteins. New therapeutic methods and drugs targeting mitophagy in ischemia-reperfusion animal models are also discussed. In-depth studies of the mechanisms underlying the regulation of mitophagy will enhance our understanding of the damage and repair processes in CIRI after CA, thereby contributing to the development of new therapeutic strategies.

ALDH2 activation attenuates oxygen-glucose deprivation/reoxygenation-induced cell apoptosis, pyroptosis, ferroptosis and autophagy

PURPOSE

It is previously reported that aldehyde dehydrogenase 2 family member (ALDH2) shows neuroprotective effects in cerebral ischemia/reperfusion injury. However, whether the protective effects are through mediating the programmed cell death is yet to be fully elucidated.

METHODS

In vitro oxygen-glucose deprivation/reoxygenation (OGD/R) model was established in HT22 cells and mouse cortical neurons. Subsequently, ALDH2 expression were assessed by qRT-PCR and western blot. The methylation status was examined by methylation-specific PCR (MS-PCR). Then, ALDH2 expression was promoted and suppressed to explore the role of ALDH2 in OGD/R-treated cells. CCK-8 assay was applied to detect cell viability, and flow cytometry was applied to evaluate cell apoptosis. Western blot was applied to detect the apoptosis-related proteins (Caspase 3, Bcl-2 and Bax), necroptosis-related proteins (RIP3 and MLKL), pyroptosis-related proteins (NLRP3 and GSDMD), ferroptosis-related protein (ACSL4 and GPX4), and autophagy-related proteins (LC3B, and p62). IL-1β and IL-18 production was evaluated by ELISA assay. Reactive oxygen species production and Fe2+ content were evaluated by the corresponding detection kit.

RESULTS

In OGD/R-treated cells, ALDH2 expression was decreased, which was due to the hypermethylation of ALDH2 in the promoter region. ALDH2 overexpression improved cell viability and ALDH2 knockdown suppressed cell viability in OGD/R-treated cells. We also found that ALDH2 overexpression attenuated OGD/R-induced cell apoptosis, pyroptosis, ferroptosis and autophagy, while ALDH2 knockdown facilitated the OGD/R-induced cell apoptosis, pyroptosis, ferroptosis and autophagy.

CONCLUSIONS

Collectively, our results implied that ALDH2 attenuated OGD/R-induced cell apoptosis, pyroptosis, ferroptosis and autophagy to promote cell viability in HT22 cells and mouse cortical neurons.

Prevalence and Impact of Cerebral Microbleeds on Clinical and Safety Outcomes in Acute Ischaemic Stroke Patients Receiving Reperfusion Therapy: A Systematic Review and Meta-Analysis

BACKGROUND

Cerebral microbleeds (CMBs), a notable neuroimaging finding often associated with cerebral microangiopathy, demonstrate a heightened prevalence in patients diagnosed with acute ischemic stroke (AIS), which is in turn linked to less favourable clinical prognoses. Nevertheless, the exact prevalence of CMBs and their influence on post-reperfusion therapy outcomes remain inadequately elucidated.

MATERIALS AND METHODS

Through systematic searches of PubMed, Embase and Cochrane databases, studies were identified adhering to specific inclusion criteria: (a) AIS patients, (b) age ≥ 18 years, (c) CMBs at baseline, (d) availability of comparative data between CMB-positive and CMB-negative groups, along with relevant post-reperfusion therapy outcomes. The data extracted were analysed using forest plots of odds ratios, and random-effects modelling was applied to investigate the association between CMBs and symptomatic intracerebral haemorrhage (sICH), haemorrhagic transformation (HT), 90-day functional outcomes, and 90-day mortality post-reperfusion therapy.

RESULTS

In a total cohort of 9776 AIS patients who underwent reperfusion therapy, 1709 had CMBs, with a pooled prevalence of 19% (ES 0.19; 95% CI: 0.16, 0.23, p < 0.001). CMBs significantly increased the odds of sICH (OR 2.57; 95% CI: 1.72; 3.83; p < 0.0001), HT (OR 1.53; 95% CI: 1.25; 1.88; p < 0.0001), as well as poor functional outcomes at 90 days (OR 1.59; 95% CI: 1.34; 1.89; p < 0.0001) and 90-day mortality (OR 1.65; 95% CI: 1.27; 2.16; p < 0.0001), relative to those without CMBs, in AIS patients undergoing reperfusion therapy (encompassing intravenous thrombolysis [IVT], endovascular thrombectomy [EVT], either IVT or EVT, and bridging therapy). Variations in the level of association can be observed among different subgroups of reperfusion therapy.

CONCLUSIONS

This meta-analysis underscores a significant association between CMBs and adverse postprocedural safety outcomes encompassing sICH, HT, poor functional outcome, and increased mortality in AIS patients undergoing reperfusion therapy. The notable prevalence of CMBs in both the overall AIS population and those undergoing reperfusion therapy emphasizes their importance in post-stroke prognostication.

Reinventing the Penumbra - the Emerging Clockwork of a Multi-modal Mechanistic Paradigm

The concept of the ischemic penumbra was originally defined as the area around a necrotic stroke core and seen as the tissue at imminent risk of further damage. Today, the penumbra is generally considered as time-sensitive hypoperfused brain tissue with decreased oxygen and glucose availability, salvageable tissue as treated by intervention, and the potential target for neuroprotection in focal stroke. The original concept entailed electrical failure and potassium release but one short of neuronal cell death and was based on experimental stroke models, later confirmed in clinical imaging studies. However, even though the basic mechanisms have translated well, conferring brain protection, and improving neurological outcome after stroke based on the pathophysiological mechanisms in the penumbra has yet to be achieved. Recent findings shape the modern understanding of the penumbra revealing a plethora of molecular and cellular pathophysiological mechanisms. We now propose a new model of the penumbra, one which we hope will lay the foundation for future translational success. We focus on the availability of glucose, the brain's central source of energy, and bioenergetic failure as core pathophysiological concepts. We discuss the relation of mitochondrial function in different cell types to bioenergetics and apoptotic cell death mechanisms, autophagy, and neuroinflammation, to glucose metabolism in what is a dynamic ischemic penumbra.

Neutrophil-Mediated Progression of Mild Cognitive Impairment to Dementia

Cognitive impairment is a serious condition that begins with amnesia and progresses to cognitive decline, behavioral dysfunction, and neuropsychiatric impairment. In the final stage, dysphagia and incontinence occur. There are numerous studies and developed drugs for cognitive dysfunction in neurodegenerative diseases, such as Alzheimer's disease (AD); however, their clinical effectiveness remains equivocal. To date, attempts have been made to overcome cognitive dysfunction and understand and delay the aging processes that lead to degenerative and chronic diseases. Cognitive dysfunction is involved in aging and the disruption of inflammation and innate immunity. Recent reports have indicated that the innate immune system is prevalent in patients with AD, and that peripheral neutrophil markers can predict a decline in executive function in patients with mild cognitive impairment (MCI). Furthermore, altered levels of pro-inflammatory interleukins have been reported in MCI, which have been suggested to play a role in the peripheral immune system during the process from early MCI to dementia. Neutrophils are the first responders of the innate immune system. Neutrophils eliminate harmful cellular debris via phagocytosis, secrete inflammatory factors to activate host defense systems, stimulate cytokine production, kill pathogens, and regulate extracellular proteases and inhibitors. This review investigated and summarized the regulation of neutrophil function during cognitive impairment caused by various degenerative diseases. In addition, this work elucidates the cellular mechanism of neutrophils in cognitive impairment and what is currently known about the effects of activated neutrophils on cognitive decline.

The mechanisms of minocycline in alleviating ischemic stroke damage and cerebral ischemia-reperfusion injury

Stroke is a group of diseases resulting from cerebral vascular rupture or obstruction and subsequent brain blood circulation disorder, leading to rapid neurological deficits. Ischemic stroke accounts for the majority of all stroke cases. The current treatments for ischemic stroke mainly include t-PA thrombolytic therapy and surgical thrombectomy. However, these interventions aimed at recanalizing cerebral vessels can paradoxically lead to ischemia-reperfusion injury, which exacerbates the severity of brain damage. Minocycline, a semi-synthetic tetracycline antibiotic, has been shown to possess a wide range of neuroprotective effects independent of its antibacterial activity. Here we summarize the mechanisms underlying the protective effects of minocycline against cerebral ischemia-reperfusion injury based on the pathogenesis of cerebral ischemia-reperfusion injury, including its modulation of oxidative stress, inflammatory response, excitotoxicity, programmed cell death and blood-brain barrier injury, and also introduce the role of minocycline in alleviating stroke-related complications, in order to provide a theoretical basis for the clinical application of minocycline in cerebral ischemia-reperfusion injury.

Microfluidic device with reconfigurable spatial temporal gradients reveals plastic astrocyte response to stroke and reperfusion

As a leading cause of mortality and morbidity, stroke constitutes a significant global health burden. Ischemic stroke accounts for 80% of cases and occurs due to an arterial thrombus, which impedes cerebral blood flow and rapidly leads to cell death. As the most abundant cell type within the central nervous system, astrocytes play a critical role within the injured brain. We developed a novel microphysiological platform that permits the induction of spatiotemporally controlled nutrient gradients, allowing us to study astrocytic response during and after transient nutrient deprivation. Within 24 h of inducing starvation in the platform, nutrient deprivation led to multiple changes in astrocyte response, from metabolic perturbations to gene expression changes, and cell viability. Furthermore, we observed that nutrient restoration did not reverse the functional changes in astrocyte metabolism, which mirrors reperfusion injury observed in vivo. We also identified alterations in numerous glucose metabolism-associated genes, many of which remained upregulated or downregulated even after restoration of the nutrient supply. Together, these findings suggest that astrocyte activation during and after nutrient starvation induces plastic changes that may underpin persistent stroke-induced functional impairment. Overall, our innovative device presents interesting potential to be used in the development of new therapies to improve tissue repair and even cognitive recovery after stroke.

Elevated white blood cell counts in ischemic stroke patients are associated with increased mortality and new vascular events

Background and purpose

High levels of white blood cells (WBC) in ischemic stroke have been shown to increase the risk of new vascular events and mortality in short and intermediate follow-up studies, but long-term effects remain unknown. We studied whether elevated levels of WBC in ischemic stroke patients are associated with new vascular events and mortality in a 10-year follow-up period.

Methods

We included ischemic stroke patients hospitalized between 2011 and 2012, categorizing their WBC counts within 48 h of stroke onset as high or normal (3.5-8.8 × 109 mmol/L; >8.8 × 109 mmol/L). Using Aahlen Johansen and Cox proportional hazard models with competing risk, we analyzed the association between WBC levels and new vascular events. Kaplan-Meier and standard Cox proportional hazard models were used to assess the risk of all-cause mortality.

Results

Among 395 patients (median age 69, [IQR: 63, 78], female patients 38,0%), 38.5% had elevated WBC at admission. During the 10-year follow-up, 113 vascular events occurred, with 46% in patients with elevated WBC and 54% in patients with normal WBC. After adjusting for relevant factors, elevated WBC levels were independently associated with increased risk of new vascular events (HR: 1.61, CI: 1.09-2.39 p < 0.05) and death (HR: 1.55, CI: 1.15-2.09, p < 0.05).

Conclusion

Elevated WBC levels in ischemic stroke patients are linked to a higher risk of new vascular events and mortality. Thus, ischemic stroke patients with elevated WBC without clinical infection need special attention to investigate possible underlying conditions to prevent future vascular events and reduce mortality. The interpretation of our results is limited by the absence of adjustment to premorbid functional status, stroke severity, and stroke treatment.

Exercise preconditioning attenuates cerebral ischemia-induced neuronal apoptosis, Th17/Treg imbalance, and inflammation in rats by inhibiting the JAK2/STAT3 pathway

BACKGROUND

Exercise preconditioning (EP) is essential for preventing ischemic stroke. Recent studies have shown that EP exerts neuroprotective effects in the cerebral ischemia-reperfusion injury model. Nonetheless, there have been few reports on the relationship between EP and the Th17/Treg balance. Moreover, it is unclear whether the JAK2/STAT3 pathway is responsible for the neuroprotective effect of EP. Therefore, we aimed to explore the impact of EP, other than the anti-inflammatory and antiapoptotic functions, on the Th17/Treg balance via the JAK2/STAT3 pathway in a middle cerebral artery occlusion (MCAO)-induced model.

RESULTS

Fifty rats were randomly allocated into five groups, including the sham group (n = 10), EP+sham group (n = 10), MCAO group (n = 10), EP+MCAO group (n = 10), and EP+MCAO+JAK2/STAT3 pathway agonist (coumermycin A1, CA1) group (n = 10). The results indicated that EP alleviated neurological deficits, reduced infarct volume, and ameliorated neuronal apoptosis induced by MCAO. Additionally, the MCAO-induced Th17/Treg imbalance could be rectified by EP. The decreased levels of IL-10 and Foxp3 and increased IL-17 and RORα in the MCAO group were reversed by EP treatment. Regarding inflammation, EP reduced the concentrations of IL-6 and IL-17 and elevated those of IL-10 and TGF-β. The neuroprotective effects of EP were accompanied by decreased phosphorylation of JAK2 and STAT3. Furthermore, CA1 pretreatment diminished all the beneficial effects of EP partially.

CONCLUSION

Our findings suggest that EP contributes to attenuating neuronal apoptosis, Th17/Treg imbalance, and inflammation induced by MCAO via inhibiting the JAK2/STAT3 pathway, indicating its therapeutic potential in ischemic stroke.

Nanoemulsions of Hydroxysafflor Yellow A for Enhancing Physicochemical and In Vivo Performance

Stroke was always a disease that threatened human life and health worldwide. We reported the synthesis of a new type of hyaluronic acid-modified multi-walled carbon nanotube. Then, we produced hydroxysafflor yellow A-hydroxypropyl-β-cyclodextrin phospholipid complex water-in-oil nanoemulsion with hyaluronic acid-modified multi-walled carbon nanotubes and chitosan (HC@HMC) for oral treatment of an ischemic stroke. We measured the intestinal absorption and pharmacokinetics of HC@HMC in rats. We found that the intestinal absorption and the pharmacokinetic behavior of HC@HMC was superior to that of HYA. We measured intracerebral concentrations after oral administration of HC@HMC and found that more HYA crossed the blood-brain barrier (BBB) in mice. Finally, we evaluated the efficacy of HC@HMC in middle cerebral artery occlusion/reperfusion (MCAO/R)-injured mice. In MCAO/R mice, oral administration of HC@HMC demonstrated significant protection against cerebral ischemia-reperfusion injury (CIRI). Furthermore, we found HC@HMC may exert a protective effect on cerebral ischemia-reperfusion injury through the COX2/PGD2/DPs pathway. These results suggest that oral administration of HC@HMC may be a potential therapeutic strategy for the treatment of stroke.

Red blood cell distribution width to platelet ratio predicts early neurological deterioration in acute ischemic stroke patients receiving intravenous thrombolysis

BACKGROUND

Inflammation plays a prominent role in the pathogenesis and progression of acute ischemic stroke (AIS). The red blood cell distribution width to platelet ratio (RPR) has been demonstrated as a novel biomarker to indicate the severity of inflammatory reaction. This study aimed to explore the association between RPR before intravenous thrombolysis and early neurological deterioration (END) after thrombolysis in AIS patients.

METHODS

AIS patients accepting intravenous thrombolysis were recruited continuously. Postthrombolysis END was defined as death or an increase in the National Institute of Health Stroke Scale (NIHSS) score ≥4 points within 24 h after intravenous thrombolysis compared to the NIHSS score before intravenous thrombolysis. We constructed univariate and multivariate logistic regression analyses to investigate the relationship of RPR before intravenous thrombolysis to postthrombolysis END. Moreover, a receiver operating characteristic (ROC) curve was applied to examine the discriminative utility of RPR before intravenous thrombolysis in predicting postthrombolysis END.

RESULTS

A total of 235 AIS patients were included, and 31 (13.19%) subjects underwent postthrombolysis END. The univariate logistic regression analysis demonstrated that RPR before intravenous thrombolysis was significantly related to postthrombolysis END (odds ratio [OR], 2.162; 95% confidence interval [CI], 1.605-2.912; P < 0.001). After adjusting for potential confounding variables with P < 0.15 in the univariate logistic regression analysis, the difference remained statistically significant (OR, 2.031; 95% CI, 1.436-2.873; P < 0.001). Furthermore, an optimal cutoff value of 7.66 for RPR before intravenous thrombolysis in predicting postthrombolysis END was observed in the ROC curve analysis, and the sensitivity and specificity were calculated as 61.3% and 81.9%, respectively (area under the curve [AUC], 0.772; 95% CI, 0.684-0.860; P < 0.001).

CONCLUSIONS

RPR before intravenous thrombolysis might be an independent risk factor for postthrombolysis END in AIS patients. Elevated levels of RPR before intravenous thrombolysis may predict postthrombolysis END.

Biomarkers of Spinal Cord Injury in Patients Undergoing Complex Endovascular Aortic Repair Procedures-A Narrative Review of Current Literature

Complex endovascular aortic repair (coEVAR) of thoracoabdominal aortic aneurysms (TAAA) has greatly evolved in the past decades. Despite substantial improvements of postoperative care, spinal cord injury (SCI) remains the most devastating complication of coEVAR being associated with impaired patient outcome and having an impact on long-term survival. The rising number of challenges of coEVAR, essentially associated with an extensive coverage of critical blood vessels supplying the spinal cord, resulted in the implementation of dedicated SCI prevention protocols. In addition to maintenance of adequate spinal cord perfusion pressure (SCPP), early detection of SCI plays an integral role in intra- and postoperative patient care. However, this is challenging due to difficulties with clinical neurological examinations during patient sedation in the postoperative setting. There is a rising amount of evidence, suggesting that subclinical forms of SCI might be accompanied by an elevation of biochemical markers, specific to neuronal tissue damage. Addressing this hypothesis, several studies have attempted to assess the potential of selected biomarkers with regard to early SCI diagnosis. In this review, we discuss biomarkers measured in patients undergoing coEVAR. Once validated in future prospective clinical studies, biomarkers of neuronal tissue damage may potentially add to the armamentarium of modalities for early SCI diagnosis and risk stratification.

Microglial and Neuronal Cell Pyroptosis Induced by Oxygen-Glucose Deprivation/Reoxygenation Aggravates Cell Injury via Activation of the Caspase-1/GSDMD Signaling Pathway

Pyroptosis is a new type of programmed cell death, which induces a strong pro-inflammatory reaction. However, the mechanism of pyroptosis after brain ischemia/reperfusion (I/R) and the interaction between different neural cell types are still unclear. This study comprehensively explored the mechanisms and interactions of microglial and neuronal pyroptosisin the simulated I/R environment in vitro. The BV2 (as microglial) and HT22(as neuronal) cells were treated by oxygen-glucose deprivation/reoxygenation (OGD/R). Both BV2 and HT22 cells underwent pyroptosis after OGD/R, and the pyroptosis occurred at earlier time point in HT22than that of BV2. Caspase-11 and Gasdermin E expression in BV2 and HT22 cells did not change significantly after OGD/R. Inhibition of caspase-1 or GSDMD activity, or down-regulation of GSDMD expression, alleviated pyroptosis in both BV2 and HT22 cells after OGD/R. Transwell studies further showed that OGD/R-treated HT22 or BV2 cells aggravated pyroptosis of adjacent non-OGD/R-treated cells, which could be relieved by inhibition of caspase-1 or GSDMD. These results suggested that OGD/R induces pyroptosis of microglia and neuronal cells and aggravates cell injury via activation of caspase-1/GSDMD signaling pathway. Our findings indicated that caspase-1 and GSDMD may be therapeutic targets after cerebral I/R.

Interferon-β modulates microglial polarization to ameliorate delayed tPA-exacerbated brain injury in ischemic stroke

Tissue plasminogen activator (tPA) is the only FDA-approved drug for the treatment of ischemic stroke. Delayed tPA administration is associated with increased risks of blood-brain barrier (BBB) disruption and hemorrhagic transformation. Studies have shown that interferon beta (IFNβ) or type I IFN receptor (IFNAR1) signaling confers protection against ischemic stroke in preclinical models. In addition, we have previously demonstrated that IFNβ can be co-administered with tPA to alleviate delayed tPA-induced adverse effects in ischemic stroke. In this study, we investigated the time limit of IFNβ treatment on the extension of tPA therapeutic window and assessed the effect of IFNβ on modulating microglia (MG) phenotypes in ischemic stroke with delayed tPA treatment. Mice were subjected to 40 minutes transient middle cerebral artery occlusion (MCAO) followed by delayed tPA treatment in the presence or absence of IFNβ at 3h, 4.5h or 6h post-reperfusion. In addition, mice with MG-specific IFNAR1 knockdown were generated to validate the effects of IFNβ on modulating MG phenotypes, ameliorating brain injury, and lessening BBB disruption in delayed tPA-treated MCAO mice. Our results showed that IFNβ extended tPA therapeutic window to 4.5h post-reperfusion in MCAO mice, and that was accompanied with attenuated brain injury and lessened BBB disruption. Mechanistically, our findings revealed that IFNβ modulated MG polarization, leading to the suppression of inflammatory MG and the promotion of anti-inflammatory MG, in delayed tPA-treated MCAO mice. Notably, these effects were abolished in MG-specific IFNAR1 knockdown MCAO mice. Furthermore, the protective effect of IFNβ on the amelioration of delayed tPA-exacerbated ischemic brain injury was also abolished in these mice. Finally, we identified that IFNβ-mediated modulation of MG phenotypes played a role in maintaining BBB integrity, because the knockdown of IFNAR1 in MG partly reversed the protective effect of IFNβ on lessening BBB disruption in delayed tPA-treated MCAO mice. In summary, our study reveals a novel function of IFNβ in modulating MG phenotypes, and that may subsequently confer protection against delayed tPA-exacerbated brain injury in ischemic stroke.

Influence of sex, age and diabetes on brain transcriptome and proteome modifications following cerebral ischemia

Ischemic stroke is a major cause of death and disability worldwide. Translation into the clinical setting of neuroprotective agents showing promising results in pre-clinical studies has systematically failed. One possible explanation is that the animal models used to test neuroprotectants do not properly represent the population affected by stroke, as most of the pre-clinical studies are performed in healthy young male mice. Therefore, we aimed to determine if the response to cerebral ischemia differed depending on age, sex and the presence of comorbidities. Thus, we explored proteomic and transcriptomic changes triggered during the hyperacute phase of cerebral ischemia (by transient intraluminal middle cerebral artery occlusion) in the brain of: (1) young male mice, (2) young female mice, (3) aged male mice and (4) diabetic young male mice. Moreover, we compared each group's proteomic and transcriptomic changes using an integrative enrichment pathways analysis to disclose key common and exclusive altered proteins, genes and pathways in the first stages of the disease. We found 61 differentially expressed genes (DEG) in male mice, 77 in females, 699 in diabetics and 24 in aged mice. Of these, only 14 were commonly dysregulated in all groups. The enrichment pathways analysis revealed that the inflammatory response was the biological process with more DEG in all groups, followed by hemopoiesis. Our findings indicate that the response to cerebral ischemia regarding proteomic and transcriptomic changes differs depending on sex, age and comorbidities, highlighting the importance of incorporating animals with different phenotypes in future stroke research studies.

Predictors of parenchymal hemorrhage after endovascular treatment in acute ischemic stroke: data from ANGEL-ACT Registry

BACKGROUND

Parenchymal hemorrhage (PH) is a troublesome complication after endovascular treatment (EVT).

OBJECTIVE

To investigate the incidence, independent predictors, and clinical impact of PH after EVT in patients with acute ischemic stroke (AIS) due to anterior circulation large vessel occlusion (LVO).

METHODS

Subjects were selected from the ANGEL-ACT Registry. PH was diagnosed according to the European Collaborative Acute Stroke Study classification. Logistic regression analyses were performed to determine the independent predictors of PH, as well as the association between PH and 90-day functional outcome assessed by modified Rankin Scale (mRS) score.

RESULTS

Of the 1227 enrolled patients, 147 (12.0%) were diagnosed with PH within 12-36 hours after EVT. On multivariable analysis, low admission Alberta Stroke Program Early CT score (ASPECTS)(adjusted OR (aOR)=1.13, 95% CI 1.02 to 1.26, p=0.020), serum glucose >7 mmol/L (aOR=1.82, 95% CI 1.16 to 2.84, p=0.009), and neutrophil-to-lymphocyte ratio (NLR; aOR=1.05, 95% CI 1.02 to 1.09, p=0.005) were associated with a high risk of PH, while underlying intracranial atherosclerotic stenosis (ICAS; aOR=0.42, 95% CI 0.22 to 0.81, p=0.009) and intracranial angioplasty/stenting (aOR=0.37, 95% CI 0.15 to 0.93, p=0.035) were associated with a low risk of PH. Furthermore, patients with PH were associated with a shift towards to worse functional outcome (mRS score 4 vs 3, adjusted common OR (acOR)=2.27, 95% CI 1.53 to 3.38, p<0.001).

CONCLUSIONS

In Chinese patients with AIS caused by anterior circulation LVO, the risk of PH was positively associated with low admission ASPECTS, serum glucose >7 mmol/L, and NLR, but negatively related to underlying ICAS and intracranial angioplasty/stenting.

TRIAL REGISTRATION NUMBER

NCT03370939.

Neutrophils in aging and aging‐related pathologies

Over the past millennia, life expectancy has drastically increased. While a mere 25 years during Bronze and Iron ages, life expectancy in many European countries and in Japan is currently above 80 years. Such an increase in life expectancy is a result of improved diet, life style, and medical care. Yet, increased life span and aging also represent the most important non-modifiable risk factors for several pathologies including cardiovascular disease, neurodegenerative diseases, and cancer. In recent years, neutrophils have been implicated in all of these pathologies. Hence, this review provides an overview of how aging impacts neutrophil production and function and conversely how neutrophils drive aging-associated pathologies. Finally, we provide a perspective on how processes of neutrophil-driven pathologies in the context of aging can be targeted therapeutically.

UBIAD1 protects against oxygen-glucose deprivation/reoxygenation injury via nNOS/NO pathway

OBJECTIVES

Cerebral infarction is a subtype of stroke with high incidence and disability rate. Ischemia reperfusion injury (IRI) is the key point of cerebral infarction treatment. UbiA prenyltransferase domain containing 1 (UBIAD1) is a kind of enzyme with various biological functions including electron transport in mitochondrial respiratory chain, lipid metabolism, and oxidative stress which are related to IRI. The purpose of this study aims to determine the neuroprotective effects and the underlying mechanisms of UBIAD1 in cerebral IRI.

METHODS

We employed oxygen-glucose deprivation/reoxygenation (OGD/R) model in mouse neuroblastoma Neuro2a (N2a) cells to mimic cerebral IRI. Lentivirus vector over-expressed UBIAD1 was transfacted into N2a cells to maintain high and stable expression of UBIAD1. In the first part of the experiment, N2a cells were divided into 5 groups: A non-OGD (N2a cells without exposure to OGD) group, groups of reoxygenation 0, 4, 12 and 24 h after 4 h of OGD, respectively. In the second part of the experiment, N2a cells were divided into 6 groups: A Con (normal cell)+non-OGD group, an EV (cell transfected with empty vector)+non-OGD group, an OE (over-expressed UBIAD1)+non-OGD group, a Con+OGD/R group, an EV+OGD/R group, and an OE+OGD/R group. In the third part, the N2a cells were divided into 8 groups: A Con+non-OGD group, an OE+non-OGD group, a Con+non-OGD+nNOS inhibitior 7-nitroindazole (7-NI) group, an OE+non-OGD+7-NI group, a Con+OGD/R group, an OE+OGD/R group, a Con+OGD/R+7-NI group, and an OE+OGD/R+7-NI group. The morphological changes of Golgi apparatus were observed under the confocal laser scanning microscope. The mRNA and protein levels of UBIAD1, secretory pathway Ca2+-ATPase isoform 1 (SPCA1), and NOS were determined by real-time PCR and Western blotting, respectively. Cell apoptosis rate was detected with flow cytometry; cell viability was detected with MTT assay, and NO release was determined with Griess assay.

RESULTS

Compared with the non-OGD group, the expression levels of UBIAD1 mRNA and protein in N2a cells in the groups of 0, 4, 12 and 24 h reoxygenation after OGD 4 h decreased significantly (P<0.05 or P<0.01), and the longer the reoxygenation time, the more significant the reduction of UBIAD1 expression. Compared with the Con+OGD/R group and the EV+OGD/R group, mRNA and protein levels of UBIAD1 and SPCA1 were increased (P<0.05 or P<0.01), the apoptosis rate was decreased (all P<0.01), and the cell viability was increased (all P<0.01) in the OE+OGD/R group. The Golgi fragmentation was less in the OE+OGD/R group than that in the Con+ OGD/R group and the EV+OGD/R group. The mRNA and protein levels of endothelial NOS (eNOS) and neuronal NOS (nNOS) were decreased (P<0.05 or P<0.01), and the level of NO was decreased (all P<0.01) in the groups over-expressed UBIAD1 (OE+non-OGD group vs Con+non-OGD group, OE+OGD/R group vs Con+OGD/R group). The level of NO and apoptosis rate of N2a cells were decreased (all P<0.01) in the the groups pretreated with 7-NI (Con+OGD/R+7-NI group vs Con+OGD/R group, OE+OGD/R+7-NI group vs OE+OGD/R group).

CONCLUSIONS

UBIAD1 may exerts protective effects on OGD/R induced N2a cells by ameliorating Golgi apparatus dysfunction via the nNOS/NO pathway.

Fasting blood glucose as a predictor of progressive infarction in men with acute ischemic stroke

Objective

Blood glucose is related to early neurological deterioration in acute ischemic stroke, but multiple mechanisms are involved in early neurological deterioration, such as progressive infarction. This study aimed to determine whether fasting blood glucose (FBG) is an independent predictor of progressive infarction.

Methods

From April 2017 to December 2020, we retrospectively enrolled 477 patients with acute ischemic stroke within 48 hours of onset. Demographic characteristics, clinical information, neuroimaging characteristics, and laboratory data were collected after admission.

Results

We found that 147 (30.8%) patients had progressive infarction. Multiple regression analysis showed that high FBG concentrations (>7.66 mmol/L) were independently associated with progressive infarction. Sex subgroup analysis showed that high FBG concentrations were an independent predictor of progressive infarction in male patients (odds ratio, 2.559; 95% confidence interval, 1.279–5.121). In a receiver operating characteristic curve analysis, FBG concentrations were a predictor of progressive infarction in all cases, especially in male patients. The cutoff value of FBG in all patients and men was 7.155 mmol/L.

Conclusions

FBG is an independent predictor of progressive infarction in patients with acute ischemic stroke within 48 hours of onset, especially in men. Patients with FBG concentrations ≥7.155 mmol/L are more likely to develop progressive infarction.

Correlation of Serum IL-1β, IL-6, and hsCRP levels with Infarct Core and Ischemic Penumbra Volume in Acute Ischemic Stroke.. [DOI: 10.21203/rs.3.rs-1882454/v2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0]

Background During cerebral ischemia, inflammatory factors such as tumor necrosis factor-alpha (TNF-α), interleukin-6 (IL-6), and IL-1β released from the ischemic core may trigger neuronal death in the ischemic penumbra, influencing infarct volume. This study aimed to understand the relationship between serum IL-1β, IL-6, and high-sensitivity C-reactive protein (hs-CRP) levels with infarct core and ischemic penumbra volume in patients with acute ischemic stroke (AIS) and its influence on prognosis. Methods The serum levels of IL-1β, IL-6, and hs-CRP were measured in 65 patients within 24h of AIS onset. The infarcts of the patients were imaged with magnetic resonance imaging and magnetic resonance angiography. Alberta Stroke Program Early Computed Tomography Score (ASPECTS) and core volume on computed tomography perfusion or perfusion-weighted imaging were used to calculate infarct volume and ischemic penumbra volume. The Tan collateral score was calculated with Neusoft Brain Clinical Assistant Ration Evaluate (NeuBrainCARE). Results We found a significant correlation between infarct core volume and serum hs-CRP levels (P < 0.05) and between penumbra volume and IL-6 levels (P < 0.05). Serum IL-6 and hs-CRP levels were positively correlated with NIHSS scores at admission, discharge, and 3 months after discharge. IL-1β levels, Tan collateral score, and ASPECTS showed no correlation with the infarct core volume. Conclusion A significant correlation between hs-CRP and IL-6 levels and infarct and ischemic penumbra volume, respectively, and with NIHSS score shows that these two factors might prove helpful in predicting the extent of neurological damage in AIS patients after 3 months of onset, opening new avenues for treatment.

Beneficial effects of capsaicin and dihydrocapsaicin on endothelial inflammation, nitric oxide production and antioxidant activity

Capsaicin and dihydrocapsaicin (DHC) are major pungent capsaicinoids produced in chili peppers. Capsaicin has been previously shown to promote vascular health by increasing nitric oxide (NO) production and reducing inflammatory responses. While capsaicin has been extensively studied, whether DHC exerts cardiovascular benefits through similar mechanisms remains unclear. The current study aimed to investigate the direct effects of DHC on endothelial inflammation, NO release, and free radical scavenging properties. DHC at concentrations up to 50 µM did not affect cell viability, while concentrations of 100 and 500 µM of DHC led to endothelial cytotoxicity. Capsaicin decreased cell viability at concentration of 500 µM. To investigate the effects of capsaicinoids on endothelial activation, we first demonstrated that TNFα induced Ser536 phosphorylation of p65 NFκB, expressions of adhesion molecules, vascular cell adhesion molecule (VCAM)-1 and intercellular adhesion molecule (ICAM)-1, and IL-6 production in primary human endothelial cells. These effects were robustly abrogated by DHC. Consistently, DHC treatment led to a marked reduction in TNFα-mediated monocyte adhesion to endothelial cells. Additionally, NO production was significantly induced by DHC and capsaicin compared to vehicle control. Similar to capsaicin and vitamin C, DHC scavenged DPPH (1,1-diphenyl-2-picrylhydrazyl) free radicals in vitro. Our present study highlights the benefits of DHC and capsaicin treatment on human endothelial cells and provides evidence to support cardiovascular benefits from capsicum consumption.

Brain Energy Metabolism in Ischemic Stroke: Effects of Smoking and Diabetes

Proper regulation of energy metabolism in the brain is crucial for maintaining brain activity in physiological and different pathophysiological conditions. Ischemic stroke has a complex pathophysiology which includes perturbations in the brain energy metabolism processes which can contribute to worsening of brain injury and stroke outcome. Smoking and diabetes are common risk factors and comorbid conditions for ischemic stroke which have also been associated with disruptions in brain energy metabolism. Simultaneous presence of these conditions may further alter energy metabolism in the brain leading to a poor clinical prognosis after an ischemic stroke event. In this review, we discuss the possible effects of smoking and/or diabetes on brain glucose utilization and mitochondrial energy metabolism which, when present concurrently, may exacerbate energy metabolism in the ischemic brain. More research is needed to investigate brain glucose utilization and mitochondrial oxidative metabolism in ischemic stroke in the presence of smoking and/or diabetes, which would provide further insights on the pathophysiology of these comorbid conditions and facilitate the development of therapeutic interventions.

Storax Protected Primary Cortical Neurons from Oxygen-Glucose Deprivation/Reoxygenation Injury via Inhibiting the TLR4/TRAF6/NF-κB Signaling Pathway

Storax is a traditional Chinese herb that is widely applied in stroke treatment. However, its neuroprotective effects and mechanisms are yet to be fully elucidated. This study aimed to elucidate the neuroprotective effects and underlying mechanisms of storax on oxygen-glucose deprivation/reoxygenation (OGD/R) in injured cortical neurons. The cortical neurons of Wistar rats were primarily cultured in vitro. TheTUNELmethod and CM-H2DCFDA probe were used to detect cell apoptosis and reactive oxygen species (ROS) expression. Enzyme-linked immunosorbent assay, reverse transcription-polymerase chain reaction, and Western blot were used to detect the expression of inflammatory cytokines and proteins of the TLR4/TRAF6/NF-κB signaling pathway. Immunofluorescence was used to measure NF-κB nuclear translocation. Transfection of TLR4 siRNA was used to detect the potential anti-inflammatory mechanisms of storax. The present results have shown that storax protected primary cortical neurons from OGD/R-induced injury by suppressing ROS generation and cell apoptosis; alleviating HMGB-1, TNF-α, IL-1β, and ICAM-1 expression; and promoting IL-10 expression. In addition, storax inhibited the activation of TLR4, TRAF6, IκBα, IKKβ, and NF-κBp65 caused by OGD/R. It is suggested that storax prevents OGD/R-induced primary cortical neuron injury by inhibiting the TLR4/TRAF6/NF-κB signaling pathway.

Investigation on the potential targets of Astragaloside IV against intracerebral hemorrhage based on network pharmacology and experimental validation

Intracerebral hemorrhage (ICH) is a life-threatening type of stroke that affects millions of individuals worldwide. Astragaloside IV (AS-IV), the main bioactive ingredient in Radix Astragali, has been linked to a variety of pharmacologic actions, including stroke. However, the effects and potential mechanisms of AS-IV on hematoma absorption after ICH are still unknown. The study aims to identify potential targets and regulation mechanisms of AS-IV on hematoma absorption after ICH. Network pharmacology, molecular docking, pharmacodynamic study, and western blot were used in this study to explore the potential mechanisms. The results showed that AS-IV could improve the hematoma absorption and neurological outcomes in collagenase VII induced rat ICH models. Molecular docking results had shown that PI3K and AKT were the potential targets of AS-IV against ICH. The experimental validation showed that AS-IV could reduce phosphorylation expression of PI3K and AKT, thereby inhibiting the NF-κB and increasing CD36 expression. This study demonstrated that AS-IV could play a critical role on hematoma absorption after ICH by regulating the PI3K/AKT signaling pathway and promoting CD36 phagocytosis, which provided a new thought for the drug development of ICH.

Dl-3-n-Butylphthalide Improves Neuroinflammation in Mice with Repeated Cerebral Ischemia-Reperfusion Injury through the Nrf2-Mediated Antioxidant Response and TLR4/MyD88/NF-κB Signaling Pathway

Increasing evidence shows that oxidative stress and neuroinflammation play a crucial role in the pathology of vascular dementia (VD). Previously, we have found that Dl-3-n-butylphthalide (NBP) has antioxidant and anti-inflammatory activities in VD, whereas little is known about its mechanism. Therefore, the objective of our study was to explore the contribution of nuclear factor erythroid-2 related factor 2 (Nrf2) to NBP and its effects on anti-inflammatory activity in a mouse model of VD. Our studies revealed that NBP could effectively mitigate cognitive deficits, neuron cell loss, and apoptosis in mice subjected to repeated cerebral ischemia-reperfusion (RCIR). Additionally, NBP promoted both the expression of brain-derived neurotrophic factor (BDNF) and tyrosine receptor kinase B (TrkB) in hippocampus tissue. NBP exhibited antioxidant activity by enhancing Nrf2 nuclear accumulation, increasing HO-1 and NQO1 expression, enhancing SOD activity, and inhibiting RCIR-induced MDA and 8-iso PGF2α generation in the hippocampus. NBP also significantly inhibited TLR4/MyD88/NF-κB signaling and suppressed microglial proliferation and the production of proinflammatory mediators in RCIR mice. Importantly, the antioxidant, antineuroinflammatory, and neuroprotective effects of NBP above were abolished by Nrf2 knockout. Collectively, these results indicated the effects of NBP on neuroinflammation were strongly associated with the Nrf2 pathway. Modulation of TLR4/MyD88/NF-κB pathway by Nrf2 is involved in the neuroprotective effect of NBP against VD induced by RCIR injury. With antioxidant and anti-neuroinflammatory properties, NBP could be a promising drug candidate for the prevention and/or treatment of VD and other neuroinflammatory disorders.

Rehmannioside A improves cognitive impairment and alleviates ferroptosis via activating PI3K/AKT/Nrf2 and SLC7A11/GPX4 signaling pathway after ischemia

ETHNOPHARMACOLOGICAL RELEVANCE

Rehmannioside A is derived from Rehmannia glutinosa Libosch, which is widely used as an important ingredient in diverse traditional Chinese medicines to treat diseases caused by "kidney deficiency" such as cerebral arteriosclerosis, aging-related stroke and dementia in China. Recent studies have proved that Rehmannia glutinosa Libosch and Rehmannioside A can improve memory capability and recover nerve damage.

AIM OF THE STUDY

To investigate the effect of Rehmannioside A on cognitive impairment after ischemia in rats and SH-SY5Y cells, and further evaluate the anti-oxidative and anti-ferroptosis mechanisms.

MATERIALS AND METHODS

Differentially expressed proteins (DEPs) in patients after cerebral ischemic stroke were revealed by a RayBio protein array. Cognitive impairment model was established by middle cerebral artery occlusion and reperfusion (MCAO) 14 days in rats. Rehmannioside A was administered intraperitoneally injection at dose of 80 mg/kg. The SH-SY5Y cells were exposed to H2O2 for 24 h and treated with Rehmannioside A (80 μM) for 24 h. The neuroprotecion of Rehmannioside A were evaluated by infarct volume (TTC), neurological defects (Garcia score) and learning memory (Morris water maze test) in vivo, and cell viability (CCK-8 or LDH) in vitro. Superoxide dismutase (SOD), malondialdehyde (MDA) and myeloperoxidase (MPO) activity of rats, glutathione (GSH), oxidized glutathione (GSSG) and nicotinamide adenine dinucleotide phosphate (NADPH) of cells were detected by biochemical assay. Intracellular reactive oxygen species (ROS) were measured by DCFH-DA assay. Myeloperoxidase (MPO), PI3 kinase (PI3K), p-PI3K, Akt, p-Akt, heme oxygenase-1 (HO-1), nuclear factor-E2-related factor 2 (Nrf2), SLC7A11, glutathione peroxidase 4 (GPX4) of the cerebral cortex in rats or SH-SY5Y cells were examined by western blotting.

RESULTS

Compared with model group, the cognitive impairment and neurological deficits of Rehmannioside A group were significantly improved, and the cerebral infarction was reduced in MCAO rats. Moreover, the cell viability obviously increased and the H2O2-induced toxicity was reduced in Rehmannioside A group. Further research indicated that the expression of p-PI3K, p-Akt, nuclear Nrf2, HO-1 and SLC7A11 in Rehmannioside A group was significantly higher than model group.

CONCLUSION

Rehmannioside A has neuroprotection effect and improves cognitive impairment after cerebral ischemia by inhibiting ferroptosis and activating PI3K/AKT/Nrf2 and SLC7A11/GPX4 signaling pathway. These findings provide valuable insight into the pathogenesis and therapeutic target of ischemic stroke.

Biochanin A as a modulator of the inflammatory response: an updated overview and therapeutic potential

Uncontrolled inflammation and failure to resolve the inflammatory response are crucial factors involved in the progress of inflammatory diseases. Current therapeutic strategies aimed at controlling excessive inflammation are effective in some cases, though they may be accompanied by severe side effects, such as immunosuppression. Phytochemicals as a therapeutic alternative can have a fundamental impact on the different stages of inflammation and its resolution. Biochanin A (BCA) is an isoflavone known for its wide range of pharmacological properties, especially its marked anti-inflammatory effects. Recent studies have provided evidence of BCA's abilities to activate events essential for resolving inflammation. In this review, we summarize the most recent findings from pre-clinical studies of the pharmacological effects of BCA on the complex signaling network associated with the onset and resolution of inflammation and BCA's potential protective functionality in several models of inflammatory diseases, such as arthritis, pulmonary disease, neuroinflammation, and metabolic disease.

Potential anti-inflammatory effect of Lamium album extract through caspase-3 and cyclooxygenase-2 genes expression in a rat model of middle cerebral artery occlusion

Introduction: Stroke is one of the most common causes of death worldwide. Inflammation and apoptosis play an important role in the cascade of ischemic stroke.

Aim: The aim of the present study was to evaluate the pretreatment effects of Lamium album (L. album) extract on caspase-3 and cyclooxygenase-2 (COX-2) expression, infarct volume, and neurological deficit score in a rat model of middle cerebral artery occlusion (MCAO).

Materials and methods: Wistar male rats were randomly divided into three groups: 1) MCAO group (1 h after MCAO, reperfusion was allowed for 24 h by retracting the thread); 2) L. album + MCAO group [receiving L. album extract (100 mg/kg via intraperitoneal) for a week before MCAO]; 3) sham group. The expression level of caspase-3 and COX-2 in the core, penumbra, and subcortex regions was measured by real time-PCR technique. Infarct volume and neurological deficit score were also assessed.

Results: The mRNA expression of caspase-3 in the core, penumbra, and subcortex regions in L. album group was significantly reduced compared to MCAO group (p&lt;0.05). Expression level of COX-2 in the subcortex of the rats exposed to L. album was statistically decreased relative to MCAO group (p&lt;0.05). Infarct volume in the core, penumbra, and subcortex was significantly reduced in the L. album group compared with MCAO group (p&lt;0.001, p&lt;0.001, p&lt;0.05, respectively). Neurological deficit score was remarkably decreased in the L. album group in comparison with the MCAO group (p&lt;0.05).

Conclusions: It appears that pretreatment with L. album extract may attenuate brain tissue damage after ischemic stroke. The potential protective effects of this plant extract against this condition might be in part attributed to its anti-inflammatory and anti-apoptotic activities.

Enhancement of cerebroprotective effects of lipid nanoparticles encapsulating FK506 on cerebral ischemia/reperfusion injury by particle size regulation

Delivery of cerebroprotective agents using liposomes has been demonstrated to be useful for treating cerebral ischemia/reperfusion (I/R) injury. We previously reported that intravenous administration of liposomes with diameters of 100 nm showed higher accumulation in the I/R region compared with larger liposomes (>200 nm) by passage through the disintegrated blood-brain barrier, suggesting a size-dependence for liposome-mediated drug delivery. Based on these findings, we hypothesized that regulation of liposomal particle size (<100 nm) may enhance the therapeutic efficacy of encapsulated drugs on cerebral I/R injury. Herein, we prepared lipid nanoparticles (LNP) with particle sizes <100 nm by the microfluidics method and compared their therapeutic potential with LNP exhibiting sizes >100 nm in cerebral I/R model rats. Intravenously administered smaller LNP (ca. 60 nm) exhibited wider accumulation and diffusivity in the brain parenchyma of the I/R region compared with larger LNP (>100 nm). Importantly, treatment with LNP encapsulating the cerebroprotective agent FK506 (FK-LNP) with particle sizes <100 nm showed greater cerebroprotective effects than FK-LNP with sizes >100 nm, and also significantly ameliorated brain injury. These results suggest that particle size regulation of LNP to sizes <100 nm can enhance the therapeutic effect of encapsulated drugs for treatment of cerebral I/R injury, and that FK-LNP could be a promising cerebroprotective agent.

Advances in Acute Ischemic Stroke Therapy

The treatment of acute ischemic stroke continues to advance. The mainstay of treatment remains intravenous thrombolysis with alteplase. Recent studies demonstrated that later treatment with alteplase is beneficial in patients selected with advanced imaging techniques. Tenecteplase has been evaluated as an alternative thrombolytic drug and evidence suggests that it is as least as effective as alteplase and may lyse large vessel clots more effectively. Endovascular therapy with mechanical thrombectomy has now been shown to be beneficial up to 24 hours after stroke onset in carefully selected patients with proximal, large vessel occlusions. Ongoing studies are evaluating the effectiveness of thrombectomy in patients with more distal vessel occlusions and patients with proximal large vessel occlusions with larger ischemic core volumes and also in patients with milder neurological deficits. Cytoprotection is another potential acute stroke therapy that has not demonstrated efficacy in prior clinical trials. It should be reconsidered as an adjunct to reperfusion and a variety of new clinical trials can be envisioned to evaluate the potential benefits of cytoprotection in patients before and after reperfusion.

Progresses and Prospects of Neuroprotective Agents-Loaded Nanoparticles and Biomimetic Material in Ischemic Stroke

Ischemic stroke remains the leading cause of death and disability, while the main mechanisms of dominant neurological damage in stroke contain excitotoxicity, oxidative stress, and inflammation. The clinical application of many neuroprotective agents is limited mainly due to their inability to cross the blood-brain barrier (BBB), short half-life and low bioavailability. These disadvantages can be better eliminated/reduced by nanoparticle as the carrier of these drugs. This review expounded the currently hot researched nanomedicines from the perspective of the mechanism of ischemic stroke. In addition, this review describes the bionic nanomedicine delivery strategies containing cells, cell membrane vesicles and exosomes that can effectively avoid the risk of clearance by the reticuloendothelial system. The potential challenges and application prospect for clinical translation of these delivery platforms were also discussed.

Preclinical Evidence of Paeoniflorin Effectiveness for the Management of Cerebral Ischemia/Reperfusion Injury: A Systematic Review and Meta-Analysis

Background: Vessel recanalization is the main treatment for ischemic stroke; however, not all patients benefit from it. This lack of treatment benefit is related to the accompanying ischemia-reperfusion (I/R) injury. Therefore, neuroprotective therapy for I/R Injury needs to be further studied. Paeonia lactiflora Pall. is a commonly used for ischemic stroke management in traditional Chinese medicine; its main active ingredient is paeoniflorin (PF). We aimed to determine the PF’s effects and the underlying mechanisms in instances of cerebral I/R injury.

Methods: We searched seven databases from their inception to July 2021.SYRCLE’s risk of bias tool was used to assess methodological quality. Review Manager 5.3 and STATA 12.0 software were used for meta-analysis.

Results: Thirteen studies, including 282 animals overall, were selected. The meta-analyses showed compared to control treatment, PF significantly reduced neurological severity scores, cerebral infarction size, and brain water content (p = 0.000). In the PF treatment groups, the apoptosis cells and levels of inflammatory factors (IL-1β) decreased compared to those in the control groups (p = 0.000).

Conclusion: Our results suggest that PF is a promising therapeutic for cerebral I/R injury management. However, to evaluate the effects and safety of PF in a more accurate manner, additional preclinical studies are necessary.

Intraarterial anti-leptin therapy via ICA protects ipsilateral CA1 neurons subjected to ischemia and reperfusion

Background

Brain reperfusion following an ischemic event is essential for tissue viability, however, it also involves processes that promote neuronal cell death. We have recently shown that local expression of the hormone leptin in cardiovascular organs drives deleterious remodeling. As cerebral ischemia-reperfusion (IR) lesions derive expression of both the leptin hormone and its receptor, we hypothesized that blocking leptin activity in the injured brain area will reduce the deleterious effects of IR injury.

Methods

C57BL6 male mice underwent bilateral common carotid artery and external carotid artery ligation. The right hemisphere was reperfused after 12 minutes, followed by intraarterial injection of either a low-dose leptin antagonist or saline solution via the ipsilateral ICA. The left common carotid artery remained ligated. Fifteen IR/leptin antagonist-injected and fourteen IR/saline-injected mice completed the experiment. Five days after surgery brains were collected and samples of the hippocampal CA1 region were analyzed for cell viability (H&E) and apoptosis (TUNEL and caspase3), for neuroinflammation (Iba1), and for signaling pathways of pSTAT3 and pSmad2.

Results

The right hemisphere hippocampal CA1 region subjected to IR and saline injection exhibited increased apoptosis and necrosis of pyramidal cells. Also, increased density of activated microglia/macrophages was evident around the CA1 region. Comparatively, leptin antagonist treatment at reperfusion reduced apoptosis and necrosis of pyramidal cells, as indicated by increased number of viable cells (p < 0.01), and reduced TUNEL (p < 0.001) and caspase3-positive cells (p<0.05). Furthermore, this treatment reduced the density of activated microglia/macrophages (p < 0.001) in the CA1 region. Signaling pathway analysis revealed that while pSTAT3 and pSmad2-positive cells were found surrounding the stratum pyramidal in saline-treated animals, pSTAT3 signal was undetected and pSmad2 was greatly reduced in this territory following leptin antagonist treatment (p < 0.01).

Conclusions

Inhibition of leptin activity in hemispheric IR injury preserved the viability of ipsilateral hippocampal CA1 neurons, likely by preventing apoptosis and local inflammation. These results indicate that intraarterial anti-leptin therapy may have clinical potential in reducing hemispheric brain IR injury.

Lipoxins in the Nervous System: Brighter Prospects for Neuroprotection

Lipoxins (LXs) are generated from arachidonic acid and are involved in the resolution of inflammation and confer protection in a variety of pathological processes. In the nervous system, LXs exert an array of protective effects against neurological diseases, including ischemic or hemorrhagic stroke, neonatal hypoxia-ischemia encephalopathy, brain and spinal cord injury, Alzheimer's disease, multiple sclerosis, and neuropathic pain. Lipoxin administration is a potential therapeutic strategy in neurological diseases due to its notable efficiency and unique superiority regarding safety. Here, we provide an overview of LXs in terms of their synthesis, signaling pathways and neuroprotective evidence. Overall, we believe that, along with advances in lipoxin-related drug design, LXs will bring brighter prospects for neuroprotection.

Application and Utility of Liposomal Neuroprotective Agents and Biomimetic Nanoparticles for the Treatment of Ischemic Stroke

Ischemic stroke is still one of the leading causes of high mortality and severe disability worldwide. Therapeutic options for ischemic stroke and subsequent cerebral ischemia/reperfusion injury remain limited due to challenges associated with drug permeability through the blood-brain barrier (BBB). Neuroprotectant delivery with nanoparticles, including liposomes, offers a promising solution to address this problem, as BBB disruption following ischemic stroke allows nanoparticles to pass through the intercellular gaps between endothelial cells. To ameliorate ischemic brain damage, a number of nanotherapeutics encapsulating neuroprotective agents, as well as surface-modified nanoparticles with specific ligands targeting the injured brain regions, have been developed. Combination therapy with nanoparticles encapsulating neuroprotectants and tissue plasminogen activator (t-PA), a globally approved thrombolytic agent, has been demonstrated to extend the narrow therapeutic time window of t-PA. In addition, the design of biomimetic drug delivery systems (DDS) employing circulating cells (e.g., leukocytes, platelets) with unique properties has recently been investigated to overcome the injured BBB, utilizing these cells’ inherent capability to penetrate the ischemic brain. Herein, we review recent findings on the application and utility of nanoparticle DDS, particularly liposomes, and various approaches to developing biomimetic DDS functionalized with cellular membranes/membrane proteins for the treatment of ischemic stroke.