Early molecular oxidative stress biomarkers of ischemic penumbra in acute stroke

Inhibition of oxidative stress contributes to the protective effect of Herba Siegesbeckiae on ischemic stroke by PI3K/STAT3/FOXO3a signal axis

ETHNOPHARMACOLOGICAL RELEVANCE

Herba Siegesbeckiae (HS), well-recognized among the commonly used traditional medicines, is popular as one of the in-clinic treatments for rheumatoid arthritis, ischemic stroke, paralysis, asthma, and allergic disorders. However, the underlying mechanisms of neuroprotection and the part played by HS in protection against neuronal apoptosis continue to be nebulous.

AIM OF THE STUDY

This study aims to explore whether HS can alleviate cerebral ischemic injury by protecting neurons and alleviating oxidative stress injury, and to elucidate the molecular mechanisms involved in PI3K/STAT3/FOXO3a signal pathway.

METHODS

In this study, both in vitro and in vivo experiments were performed to examine the neuroprotective effects of HS on oxidative stress injury and neuronal apoptosis. After the HS treatment, several assays were done to assess the neuroprotection, oxidative stress response, and neuronal apoptosis. Besides, to further clarify the role of HS on the PI3K/STAT3/FOXO3a signal pathway, the effects of combining the HS with an inhibitor, agonist, or siRNA were studied.

RESULTS

From the in vivo and in vitro experiments, it was evident that HS inhibited neuronal apoptosis to a significant degree and offered effective protection against oxidative stress injury by lowering the concentration of the reactive oxygen species (ROS), malondialdehyde (MDA), superoxide dismutase (SOD) and glutathione (GSH). Moreover, HS obviously up-regulated the principal proteins expression of the PI3K/STAT3/FOXO3a signal pathway, including the PI3K, p-Akt/Akt, and p-FOXO3a/FOXO3a. Additionally, HS reduced the fluorescence intensity of the STAT3 and FOXO3a, and advanced their nuclear translocation both in the in vitro and in vivo models. Nevertheless, after the combined treatment with HS and LY294002, Colivelin or siRNA-FOXO3a, these effects were reversed.

CONCLUSIONS

The present study gives pharmacological evidence, revealing that HS wields its protective actions by regulating the PI3K/STAT3/FOXO3a signal pathway, thus inhibiting oxidative stress injury and protecting the neurons from oxidative stress-generated damage. The current study emphasizes the potential of HS as a therapeutic means of treatment of oxidative stress conditions related to ischemic stroke.

Mogroside V ameliorates astrocyte inflammation induced by cerebral ischemia through suppressing TLR4/TRADD pathway

Inflammation and oxidative stress are pivotal factors in the onset and progression of secondary injury following cerebral ischemia-reperfusion (I/R). Mogroside V (MV), a primary active compound of Siraitia grosvenorii, exhibits significant anti-inflammatory and antioxidant properties. However, its specific effects in cerebral ischemia remain unclear. In this study, we evaluated the neuroprotective effects of MV in a model of focal cerebral ischemia. Male C57BL/6J mice were subjected to middle cerebral artery occlusion/reperfusion (MCAO/R) as an in vivo model of cerebral ischemia-reperfusion injury (CIRI), while U87 cells were subjected to oxygen-glucose deprivation/reoxygenation (OGD/R) to simulate CIRI in vitro. MV administration was found to reduce mortality, infarct volume, cerebral edema, and alleviate neurological deficits in these I/R mice. Furthermore, MV mitigated cerebral I/R injury by decreasing oxidative stress markers, such as reactive oxygen species (ROS) and malondialdehyde (MDA), while enhancing superoxide dismutase (SOD) levels. Gene Set Enrichment Analysis (GSEA) of the KEGG pathway revealed that most differentially expressed genes (DEGs) were involved in the Toll-like receptor/NF-κB/TNF/apoptosis signaling pathway. These findings were confirmed by real-time PCR, western blotting, immunohistochemistry, and immunofluorescence co-localization which demonstrated that MV reduced astrocyte inflammatory responses by inhibiting cytokine secretion associated with the TLR4/TRADD pathway. Additionally, MV protected neurons from apoptosis, as supported by TUNEL, Nissl, and HE staining. In conclusion, MV attenuates astrocyte inflammation and exerts neuroprotective effects following cerebral I/R injury, likely through suppression of the TLR4/TRADD signaling pathway.

Association of Uric Acid, High-Sensitivity C-Reactive Protein, and 90-Day Risk of Poor Function Outcome in Patients with Ischemic Stroke or Transient Ischemic Attacks

Aim

The interaction between inflammatory biomarkers (high-sensitivity C-reactive protein, hsCRP) and antioxidants (uric acid, UA) regarding prognosis after ischemic stroke or transient ischemic attack (TIA) remains inadequately explored. This study aimed to assess (1) the individual and joint effects of hsCRP and UA, and (2) the neuroprotective role of UA in patients with elevated hsCRP levels concerning poor functional outcomes at 90 days.

Methods

A prospective cohort study was conducted involving 2140 consecutive ischemic stroke or TIA patients with hsCRP and UA levels. The primary outcome was defined as a poor functional outcome, indicated by a modified Rankin Scale (mRS) score of 3-6 at 90 days, with a shift in the mRS score as a secondary outcome. Logistic regression and propensity score (PS) analyses were employed to ensure robustness.

Results

Poor functional outcome occurred in 345 (16.1%) patients. Individual effects found that the highest quartiles of hsCRP (adjusted OR = 3.090; 95% CI 2.150-4.442) and UA (adjusted OR = 0.671; 95% CI 0.551-0.883) were associated with increased or decreased risk of poor functional outcome, respectively. Joint effects (adjusted OR = 3.994; 95% CI 2.758-5.640) between hsCRP and UA on the primary outcome were more apparent in patients with high hsCRP levels (hsCRP > 1.60 mg/L) and low UA levels (UA ≤ 291.85 µmol/L). For the patients with high hsCRP levels, patients with low UA levels had a higher risk of primary and secondary outcomes, compared with those with high UA levels, after unadjusted or adjusted for hsCRP. Similar and reliable results were observed in PS-based models.

Conclusion

In patients with ischemic stroke or TIA, joint high levels of hsCRP and low UA levels significantly correlate with increased risk of poor functional outcome at 90 days. In addition, high UA levels could reduce the risk of poor functional outcome for patients with high hsCRP levels.

Isoliquiritigenin alleviates cerebral ischemia-reperfusion injury by reducing oxidative stress and ameliorating mitochondrial dysfunction via activating the Nrf2 pathway

Cerebral ischemia-reperfusion injury (CIRI) refers to a secondary brain injury that occurs when blood supply is restored to ischemic brain tissue and is one of the leading causes of adult disability and mortality. Multiple pathological mechanisms are involved in the progression of CIRI, including neuronal oxidative stress and mitochondrial dysfunction. Isoliquiritigenin (ISL) has been preliminarily reported to have potential neuroprotective effects on rats subjected to cerebral ischemic insult. However, the protective mechanisms of ISL have not been elucidated. This study aims to further investigate the effects of ISL-mediated neuroprotection and elucidate the underlying molecular mechanism. The findings indicate that ISL treatment significantly alleviated middle cerebral artery occlusion (MCAO)-induced cerebral infarction, neurological deficits, histopathological damage, and neuronal apoptosis in mice. In vitro, ISL effectively mitigated the reduction of cell viability, Na+-K+-ATPase, and MnSOD activities, as well as the degree of DNA damage induced by oxygen-glucose deprivation (OGD) injury in PC12 cells. Mechanistic studies revealed that administration of ISL evidently improved redox homeostasis and restored mitochondrial function via inhibiting oxidative stress injury and ameliorating mitochondrial biogenesis, mitochondrial fusion-fission balance, and mitophagy. Moreover, ISL facilitated the dissociation of Keap1/Nrf2, enhanced the nuclear transfer of Nrf2, and promoted the binding activity of Nrf2 with ARE. Finally, ISL obviously inhibited neuronal apoptosis by activating the Nrf2 pathway and ameliorating mitochondrial dysfunction in mice. Nevertheless, Nrf2 inhibitor brusatol reversed the mitochondrial protective properties and anti-apoptotic effects of ISL both in vivo and in vitro. Overall, our findings revealed that ISL exhibited a profound neuroprotective effect on mice following CIRI insult by reducing oxidative stress and ameliorating mitochondrial dysfunction, which was closely related to the activation of the Nrf2 pathway.

Permselectivity of Silk Fibroin Hydrogels for Advanced Drug Delivery Neurotherapies

A promising trend in tissue engineering is using biomaterials to improve the control of drug concentration in targeted tissue. These vehicular systems are of specific interest when the required treatment time window is higher than the stability of therapeutic molecules in the body. Herein, the capacity of silk fibroin hydrogels to release different molecules and drugs in a sustained manner was evaluated. We found that a biomaterial format, obtained by an entirely aqueous-based process, could release molecules of variable molecular weight and charge with a preferential delivery of negatively charged molecules. Although the theoretical modeling suggested that drug delivery was more likely to be driven by Fickian diffusion, the external media had a considerable influence on the release, with lipophilic organic solvents such as acetonitrile-methanol (ACN-MeOH) intensifying the release of hydrophobic molecules. Second, we found that silk fibroin could be used as a vehicular system to treat a variety of brain disorders as this biomaterial sustained the release of different factors with neurotrophic (brain-derived neurotrophic factor) (BDNF), chemoattractant (C-X-C motif chemokine 12) (CXCL12), anti-inflammatory (TGF-β-1), and angiogenic (VEGF) capacities. Finally, we demonstrated that this biomaterial hydrogel could release cholesteronitrone ISQ201, a nitrone with antioxidant capacity, showing neuroprotective activity in an in vitro model of ischemia-reoxygenation. Given the slow degradation rate shown by silk fibroin in many biological tissues, including the nervous system, our study expands the restricted list of drug delivery-based biomaterial systems with therapeutic capacity for both short- and especially long-term treatment windows and has merit for use with brain pathologies.

Developing targeted antioxidant nanomedicines for ischemic penumbra: Novel strategies in treating brain ischemia-reperfusion injury

During cerebral ischemia-reperfusion conditions, the excessive reactive oxygen species in the ischemic penumbra region, resulting in neuronal oxidative stress, constitute the main pathological mechanism behind ischemia-reperfusion damage. Swiftly reinstating blood perfusion in the ischemic penumbra zone and suppressing neuronal oxidative injury are key to effective treatment. Presently, antioxidants in clinical use suffer from low bioavailability, a singular mechanism of action, and substantial side effects, severely restricting their therapeutic impact and widespread clinical usage. Recently, nanomedicines, owing to their controllable size and shape and surface modifiability, have demonstrated good application potential in biomedicine, potentially breaking through the bottleneck in developing neuroprotective drugs for ischemic strokes. This manuscript intends to clarify the mechanisms of cerebral ischemia-reperfusion injury and provides a comprehensive review of the design and synthesis of antioxidant nanomedicines, their action mechanisms and applications in reversing neuronal oxidative damage, thus presenting novel approaches for ischemic stroke prevention and treatment.

Omentin-1 May Be One Treatment Factor for Intravenous Thrombolysis of Acute Cerebral Infarction Through the Inhibition of NLRP3 Ubiquitination by AMPK Function: Preliminary Findings

BACKGROUND

Acute cerebral infarction (ACI) is a common neurological disease that is associated with high morbidity, disability and mortality rates. At present, antiplatelet therapy is a necessary treatment for ACI. The present study aimed to investigate the effects of omentin-1 on the intravenous thrombolysis of ACI.

OBJECTIVE

The present study aimed to investigate the effects of omentin-1 on the intravenous thrombolysis of ACI.

MATERIAL AND METHODS

The mouse model of ACI was induced using male C57BL/6 mice through middle cerebral artery occlusion (MCAO). Meanwhile, the murine BV2 microglial cells were pretreated with 0.1 mg/ml of lipopolysaccharide (LPS), and then induced with 2 mM of adenosine triphosphate (ATP).

RESULTS

The omentin-1 mRNA expression in patients receiving intravenous thrombolysis for ACI was down-regulated compared with the normal group. Additionally, the serum level of omentin-1 was negatively correlated with National Institute of Health Stroke Scale (NIHSS) score or serum level of IL-1β or MMP-2 in patients receiving intravenous thrombolysis for ACI. Meanwhile, the serum mRNA expression of omentin-1 was positively correlated with Barthel index or high-sensitivity C-reactive protein (hs-CRP) in patients undergoing intravenous thrombolysis for ACI. As observed from the in vitro model, Omentin-1 reduced inflammation, promoted cell growth, alleviated ROS-induced oxidative stress, and enhanced AMPK activity through activating NLRP3 ubiquitination. Omentin-1 presented ACI in the mouse model of ACI. Regulating AMPK activity contributed to controlling the effects of Omentin-1 on the in vitro model.

CONCLUSIONS

Omentin-1 reduced neuroinflammation and ROS-induced oxidative stress in the mouse model of ACI, which was achieved by inhibiting NLRP3 ubiquitination through regulating AMPK activity. Therefore, omentin-1 may serve as a treatment factor for the intravenous thrombolysis of ACI in further clinical application.

Left atrial appendage flow velocity predicts occult atrial fibrillation in cryptogenic stroke: a CRYPTON-ICM registry

BACKGROUND

An insertable cardiac monitor (ICM) and transesophageal echocardiography (TEE) are useful for investigating potential embolic sources in cryptogenic stroke, of which atrial fibrillation (AF) is a critical risk factor for stroke recurrence. The association of left atrial appendage flow velocity (LAA-FV) on TEE with ICM-detected AF is yet to be elucidated.

METHODS

CRYPTON-ICM (CRYPTOgenic stroke evaluation in Nippon using ICM) is a multicenter registry of cryptogenic stroke with ICM implantation, and patients whose LAA-FV was evaluated on TEE were enrolled. The primary outcome was the detection of AF (> 2 min) on ICM. Receiver operating characteristic (ROC) curve analysis was performed to determine the optimal cut-off of LAA-FV, and factors associated with ICM-detected AF were assessed.

RESULTS

A total of 307 patients (age 66.6 ± 12.3 years; 199 males) with median follow-up of 440 (interquartile range 169-726) days were enrolled; AF was detected in 101 patients. The lower-tertile LAA-FV group had older age, more history of congestive heart failure, and higher levels of B-type natriuretic peptide (BNP) or N-terminal proBNP (all P < 0.05). On ROC analysis, LAA-FV < 37.5 cm/s predicted ICM-detected AF with sensitivity of 26.7% and specificity of 92.2%. After adjustment for covariates, the lower tertile of LAA-FV (hazard ratio [HR], 1.753 [1.017-3.021], P = 0.043) and LAA-FV < 37.5 cm/s (HR 1.987 [1.240-3.184], P = 0.004) predicted ICM-detected AF.

CONCLUSIONS

LAA-FV < 37.5 cm/s predicts AF. TEE is useful not only to evaluate potential embolic sources, but also for long-term detection of AF on ICM by measuring LAA-FV in cryptogenic stroke. http://www.umin.ac.jp/ctr/ (UMIN000044366).

The Role of Potential Oxidative Biomarkers in the Prognosis of Acute Ischemic Stroke and the Exploration of Antioxidants as Possible Preventive and Treatment Options

Ischemic strokes occur when the blood supply to a part of the brain is interrupted or reduced due to arterial blockage, and it often leads to damage to brain cells or death. According to a myriad of experimental studies, oxidative stress is an important pathophysiological mechanism of ischemic stroke. In this narrative review, we aimed to identify how the alterations of oxidative stress biomarkers could suggest a severity-reflecting diagnosis of ischemic stroke and how these interactions may provide new molecular targets for neuroprotective therapies. We performed an eligibility criteria-based search on three main scientific databases. We found that patients with acute ischemic stroke are characterized by increased oxidative stress markers levels, such as the total antioxidant capacity, F2-isoprostanes, hydroxynonenal, total and perchloric acid oxygen radical absorbance capacity (ORACTOT and ORACPCA), malondialdehyde (MDA), myeloperoxidase, and urinary 8-oxo-7,8-dihydro-2′-deoxyguanosine. Thus, acute ischemic stroke is causing significant oxidative stress and associated molecular and cellular damage. The assessment of these molecular markers could be useful in diagnosing ischemic stroke, finding its causes, predicting its severity and outcomes, reducing its impact on the cellular structures of the brain, and guiding preventive treatment towards antioxidant-based therapy as novel therapeutic alternatives.

Synaptotagmin-3 interactions with GluA2 mediate brain damage and impair functional recovery in stroke

Synaptotagmin III (Syt3) is a Ca2+-dependent membrane-traffic protein that is highly concentrated in synaptic plasma membranes and affects synaptic plasticity by regulating post-synaptic receptor endocytosis. Here, we show that Syt3 is upregulated in the penumbra after ischemia/reperfusion (I/R) injury. Knockdown of Syt3 protects against I/R injury, promotes recovery of motor function, and inhibits cognitive decline. Overexpression of Syt3 exerts the opposite effects. Mechanistically, I/R injury augments Syt3-GluA2 interactions, decreases GluA2 surface expression, and promotes the formation of Ca2+-permeable AMPA receptors (CP-AMPARs). Using a CP-AMPAR antagonist or dissociating the Syt3-GluA2 complex via TAT-GluA2-3Y peptide promotes recovery from neurological impairments and improves cognitive function. Furthermore, Syt3 knockout mice are resistant to cerebral ischemia because they show high-level expression of surface GluA2 and low-level expression of CP-AMPARs after I/R. Our results indicate that Syt3-GluA2 interactions, which regulate the formation of CP-AMPARs, may be a therapeutic target for ischemic insults.

Accurately quantified plasma free glycine concentration as a biomarker in patients with acute ischemic stroke

We developed a hollow fiber centrifugal ultrafiltration (HFCF-UF) method to study the change of plasma levels of free glycine (Gly) in patients with acute ischemic stroke (AIS). Twenty-four patients with AIS confirmed by diffusion-weighted imaging (DWI) were enrolled. During the study period, the patients did not receive any supplemental amino acids therapy that could affect the obtained results. Our results showed that although AIS patients adopted different methods of treatment (thrombolytic and non-thrombolytic), the clinical NIHSS score of AIS showed a downward trend whereas Gly concentration showed increased trend. Moreover, plasma free Gly concentration was positively correlated with ASPECTS score. The correlation between Gly levels and infarct volume showed a statistical significance. That is to say, higher Gly level predicted smaller infarct size. Thus, the change of free Gly level in plasma could be considered as a potential biomarker of AIS.

Polymorphisms of the Matrix Metalloproteinase Genes are Associated with Acute Ischemic Stroke in Chinese Han Population

Background and Purpose

Studies have shown that matrix metalloproteinase (MMP-2,3,9) plays an important role in the pathologic process of ischemic stroke (IS). The aim of this study was to investigate the relationship between C1306T, 1612-5A/6A, C-1562T polymorphisms of MMP-2,3,9 genes and IS in Chinese Han population.

Methods

The polymorphisms of MMP-2(C1306T), -3(1612-5A/6A), -9(C-1562T) gene were detected by PCR-RFLP and SNaPshot sequencing. Then, stratified analysis was used to study the relationship between IS subtypes and MMP-2,3,9 polymorphisms.

Results

For the MMP-2 gene C1306T polymorphism, TT genotype and T allele were significantly associated with a reduced risk of IS (P = 0.015, P = 0.003, respectively). T allele was significantly associated with a reduced risk of small artery occlusion (SAO) subtype compared with the control group (P = 0.012, OR = 0.550, 95% CI = 0.065-1.291). For the MMP-3 gene-1612 (5A/6A) polymorphism, 5A/5A genotype was significantly increased in the IS group (P = 0.011, OR = 0.370, 95% CI = 0.168-0.814), especially in the large-artery atherosclerosis (LAA) subtype (P = 0.001, OR = 2.345) as compared to the control group.

Conclusion

Our study suggested that the T allele of MMP-2 may be a protective factor of IS, especially in SAO subtype, while the 5A/5A gene of MMP-3 may increase the risk of IS, especially in LAA subtype in Chinese Han population.

CDC42 Might Be a Molecular Signature of DWI-FLAIR Mismatch in a Nonhuman Primate Stroke Model

No definitive blood markers of DWI-FLAIR mismatch, a pivotal indicator of salvageable ischemic penumbra brain tissue, are known. We previously reported that CDC42 and RHOA are associated with the ischemic penumbra. Here, we investigated whether plasma CDC42 and RHOA are surrogate markers of DWI-FLAIR mismatch. Sixteen cynomolgus macaques (3 as controls and 13 for the stroke model) were included. Guided by digital subtraction angiography (DSA), a middle cerebral artery occlusion (MCAO) model was established by occluding the middle cerebral artery (MCA) with a balloon. MRI and neurological deficit scoring were performed to evaluate postinfarction changes. Plasma CDC42 and RHOA levels were measured by enzyme-linked immunosorbent assay (ELISA). The stroke model was successfully established in eight monkeys. Based on postinfarction MRI images, experimental animals were divided into a FLAIR (-) group (N = 4) and a FLAIR (+) group (N = 4). Plasma CDC42 in the FLAIR (-) group showed a significant decrease compared with that in the FLAIR (+) group (p < 0.05). No statistically significant difference was observed for plasma RHOA. The FLAIR (-) group showed a milder neurological function deficit and a smaller infarct volume than the FLAIR (+) group (p < 0.05). Therefore, plasma CDC42 might be a new surrogate marker for DWI-FLAIR mismatch.

Association of Blood Biomarkers of Inflammation With Penumbra Consumption After Mechanical Thrombectomy in Patients With Acute Ischemic Stroke

BACKGROUND AND OBJECTIVES

The objective of this study was to assess the relationship between blood biomarkers of inflammation and lesion growth within the penumbra in acute ischemic stroke (AIS) patients treated with mechanical thrombectomy (MT).

METHODS

The HIBISCUS-STROKE cohort enrolled patients admitted in the Lyon Stroke Center for an anterior circulation AIS treated with MT after brain MRI assessment. Lesion growth within the penumbra was assessed on day 6 MRI using a voxel-based nonlinear coregistration method and dichotomized into low and high according to the median value. C-reactive protein, interleukin (IL)-6, IL-8, IL-10, monocyte chemoattractant protein-1, soluble tumor necrosis factor receptor I, soluble form suppression of tumorigenicity 2 (sST2), soluble P-selectin, vascular cellular adhesion molecule-1, and matrix metalloproteinase-9 were measured in sera at 4 time points within the first 48 hours. Reperfusion was considered as successful if Thrombolysis in Cerebral Infarction score was 2b/2c/3. A multiple logistic regression model was performed to detect any association between area under the curve (AUC) of these biomarkers within the first 48 hours and a high lesion growth within the penumbra.

RESULTS

Ninety patients were included. The median lesion growth within the penumbra was 2.3 (0.7-6.2) mL. On multivariable analysis, a high sST2 AUC (OR 3.77, 95% CI 1.36-10.46), a high baseline DWI volume (OR 3.65, 95% CI 1.32-10.12), and a lack of successful reperfusion (OR 0.19, 95% CI 0.04-0.92) were associated with a high lesion growth within the penumbra. When restricting analyses to patients with successful reperfusion (n = 76), a high sST2 AUC (OR 5.03, 95% CI 1.64-15.40), a high baseline DWI volume (OR 3.74, 95% CI 1.22-11.53), and a high penumbra volume (OR 3.25, 95% CI 1.10-9.57) remained associated with a high lesion growth within the penumbra.

DISCUSSION

High sST2 levels within the first 48 hours are associated with a high lesion growth within the penumbra.

Neurovascular Unit-Derived Extracellular Vesicles: From Their Physiopathological Roles to Their Clinical Applications in Acute Brain Injuries

Extracellular vesicles (EVs) form a heterogeneous group of membrane-enclosed structures secreted by all cell types. EVs export encapsulated materials composed of proteins, lipids, and nucleic acids, making them a key mediator in cell–cell communication. In the context of the neurovascular unit (NVU), a tightly interacting multicellular brain complex, EVs play a role in intercellular communication and in maintaining NVU functionality. In addition, NVU-derived EVs can also impact peripheral tissues by crossing the blood–brain barrier (BBB) to reach the blood stream. As such, EVs have been shown to be involved in the physiopathology of numerous neurological diseases. The presence of NVU-released EVs in the systemic circulation offers an opportunity to discover new diagnostic and prognostic markers for those diseases. This review outlines the most recent studies reporting the role of NVU-derived EVs in physiological and pathological mechanisms of the NVU, focusing on neuroinflammation and neurodegenerative diseases. Then, the clinical application of EVs-containing molecules as biomarkers in acute brain injuries, such as stroke and traumatic brain injuries (TBI), is discussed.

An ischemia-homing bioengineered nano-scavenger for specifically alleviating multiple pathogeneses in ischemic stroke

BACKGROUND

Ischemic stroke is one of the most serious global public health problems. However, the performance of current therapeutic regimens is limited due to their poor target specificity, narrow therapeutic time window, and compromised therapeutic effect. To overcome these barriers, we designed an ischemia-homing bioengineered nano-scavenger by camouflaging a catalase (CAT)-loaded self-assembled tannic acid (TA) nanoparticle with a M2-type microglia membrane (TPC@M2 NPs) for ischemic stroke treatment.

RESULTS

The TPC@M2 NPs can on-demand release TA molecules to chelate excessive Fe2+, while acid-responsively liberating CAT to synergistically scavenge multiple ROS (·OH, ·O2-, and H2O2). Besides, the M2 microglia membrane not only can be served as bioinspired therapeutic agents to repolarize M1 microglia into M2 phenotype but also endows the nano-scavenger with ischemia-homing and BBB-crossing capabilities.

CONCLUSIONS

The nano-scavenger for specific clearance of multiple pathogenic elements to alleviate inflammation and protect neurons holds great promise for combating ischemic stroke and other inflammation-related diseases.

Preparation of baicalin-loaded ligand-modified nanoparticles for nose-to-brain delivery for neuroprotection in cerebral ischemia

Neuroprotection in cerebral ischemia (CI) has received increasing attention. However, efficient delivery of therapeutic agents to the brain remains a major challenge due to the complex environment of the brain. Nose-to-brain-based delivery is a promising approach. Here, we optimized a nanocarrier formulation of neuroprotective agents that can be used for nose-to-brain delivery by obtaining RVG29 peptide-modified polyethylene glycol–polylactic acid-co-glycolic acid nanoparticles (PEG–PLGA RNPs) that have physicochemical properties that lead to stable and sustained drug release and thereby improve the bioavailability of neuroprotective agents. The brain-targeting ability of PEG–PLGA RNPs administered through nasal inhalation was verified in a rat model of CI. It was found that delivery to the whole brain can be achieved with little delivery to the peripheral circulation. Baicalin (BA) was selected as the neuroprotective agent for delivery. After intranasal administration of BA–PEG–PLGA RNPs, the neurological dysfunction of rats with ischemic brain injury was significantly alleviated, the cerebral infarction area was reduced, and nerve trauma and swelling were relieved. Furthermore, it was demonstrated that the neuroprotective effects of BA in a rat model of CI may be mediated by inhibition of inflammation and alleviation of oxidative stress. The immunohistochemical results obtained after treatment with nanoparticles loaded with BA showed that Nrf2/HO-1 was activated in the area in which ischemic brain damage had occurred and that its expression was significantly higher in the group treated with BA–PEG–PLGA RNPs than in the other groups. The ELISA results showed that the levels of IL-1β, IL-6, and TNF-α were abnormally increased in the serum of rats with cerebral ischemia. After treatment with BA-loaded nanoparticles, IL-1β, IL-6, and TNF-α levels decreased significantly. Oxidative stress was alleviated; the levels of glutathione and superoxide dismutase increased; and the levels of reactive oxygen species and malondialdehyde decreased, in animals to which BA–PEG–PLGA RNPs were delivered by intranasal inhalation. In conclusion, BA–PEG–PLGA RNPs can effectively deliver BA to rats and thereby exert neuroprotective effects against CI.

Huangqi-Honghua Combination Prevents Cerebral Infarction with Qi Deficiency and Blood Stasis Syndrome in Rats by the Autophagy Pathway

BACKGROUND

Cerebral ischemia/reperfusion injury (CI/RI) contributes to the process of autophagy. Huangqi-Honghua combination (HQ-HH) is a traditional Chinese medicine (TCM) combination that has been widely used in the treatment of cerebrovascular diseases in China. The role of autophagy in HQ-HH-mediated treatment of CI/RI is unclear.

METHODS

Sprague-Dawley (SD) rats were used to establish the middle cerebral artery occlusion (MCAO) with QDBS syndrome model and evaluate the function of HQ-HH in protecting against CI/RI.

RESULTS

HQ-HH significantly improved the neuronal pathology and reduced infarct volume, neurological deficits, and whole blood viscosity in rats with CI/RI. Western blot results showed that the expression of autophagy marker proteins LC3II/LC3I and Beclin1 in the HQ-HH group was significantly lower than that in the model group, while the expression of p62 was significantly higher in the HQ-HH group as compared with the model group. There were no significant differences in PI3K, Akt, and mTOR levels between the HQ-HH group and the model group; however, p-PI3K, p-Akt, and p-mTOR were significantly upregulated. In addition, HQ-HH also changed the composition and function of intestinal flora in MCAO + QDBS model rats.

CONCLUSION

HQ-HH protects from CI/RI, and its underlying mechanism may involve the activation of the PI3K-Akt-mTOR signaling pathway, relating to the changes in the composition of intestinal flora.

Exploring the Mechanism of Edaravone for Oxidative Stress in Rats with Cerebral Infarction Based on Quantitative Proteomics Technology

Objective

To explore the mechanism of edaravone in the treatment of oxidative stress in rats with cerebral infarction based on quantitative proteomics technology.

Method

The modified Zea Longa intracavitary suture blocking method was utilized to make rat CI model. After modeling, the rat was intragastrically given edaravone for 7 days, once a day. After the 7-day intervention, the total proteins of serum were extracted. After proteomics analysis, the differentially expressed proteins are analyzed by bioinformatics. Then chemoinformatics methods were used to explore the biomolecular network of edaravone intervention in CI.

Result

The neurological scores and pathological changes of rats were improved after the intervention of edaravone. Proteomics analysis showed that in the model/sham operation group, 90 proteins in comparison group were upregulated, and 26 proteins were downregulated. In the edaravone/model group, 21 proteins were upregulated, and 41 proteins were downregulated. Bioinformatics analysis and chemoinformatics analysis also show that edaravone is related to platelet activation and aggregation, oxidative stress, intercellular adhesion, glycolysis and gluconeogenesis, iron metabolism, hypoxia, inflammatory chemokines, their mediated signal transduction, and so on.

Conclusion

The therapeutic mechanism of edaravone in the treatment of CI may involve platelet activation and aggregation, oxidative stress, intercellular adhesion, glycolysis and gluconeogenesis, iron metabolism, hypoxia, and so on. This study revealed the serum protein profile of edaravone in the treatment of cerebral infarction rats through serum TMT proteomics and discovered the relevant mechanism of edaravone regulating iron metabolism in cerebral infarction, which provides new ideas for the study of edaravone intervention in cerebral infarction and also provides reference information for future research on the mechanism of edaravone intervention in iron metabolism-related diseases.

Neutrophils and Platelets: Immune Soldiers Fighting Together in Stroke Pathophysiology

Neutrophils and platelets exhibit a diverse repertoire of functions in thromboinflammatory conditions such as stroke. Most cerebral ischemic events result from longstanding chronic inflammation secondary to underlying pathogenic conditions, e.g., hypertension, diabetes mellitus, obstructive sleep apnea, coronary artery disease, atrial fibrillation, morbid obesity, dyslipidemia, and sickle cell disease. Neutrophils can enable, as well as resolve, cerebrovascular inflammation via many effector functions including neutrophil extracellular traps, serine proteases and reactive oxygen species, and pro-resolving endogenous molecules such as Annexin A1. Like neutrophils, platelets also engage in pro- as well as anti-inflammatory roles in regulating cerebrovascular inflammation. These anucleated cells are at the core of stroke pathogenesis and can trigger an ischemic event via adherence to the hypoxic cerebral endothelial cells culminating in aggregation and clot formation. In this article, we review and highlight the evolving role of neutrophils and platelets in ischemic stroke and discuss ongoing preclinical and clinical strategies that may produce viable therapeutics for prevention and management of stroke.

Acute Inflammation in Cerebrovascular Disease: A Critical Reappraisal with Focus on Human Studies

Recent attention has been focused on the field of inflammatory biomarkers associated with vascular disorders, regarding diagnosis, prognosis, and possible therapeutical targets. In this study, we aimed to perform a comprehensive review of the literature regarding the use of inflammatory biomarkers in stroke patients. We searched studies that evaluated inflammation biomarkers associated with Cerebrovascular Disease (CVD), namely, ischemic Stroke (IS), Intracerebral Hemorrhage (ICH) and Cerebral Venous Thrombosis (CVT). As of today, neutrophil–lymphocyte ratio (NLR) seems the be the most widely studied and accepted biomarker for cerebrovascular disease due to its easy access and availability. Although demonstrated as a prognostic risk factor, in IS, ICH and CVT, its diagnostic role is still under investigation. Several other prognostic factors could be used or even combined together into a diagnostic or prognostic index. Multiple inflammatory biomarkers appear to be involved in IS, ICH, and CVT. Blood inflammatory cells, easily measured and accessible at admission may provide information regarding accurate diagnosis and prognosis. Although not yet a reality, increasing evidence exists to suggest that these may become potential therapeutic targets, likely influencing or mitigating complications of CVD and improving prognosis. Nevertheless, further larger, well-designed randomized clinical trials are still needed to follow up this hypothesis.

Identifying patients with cerebral infarction within the time window compatible with reperfusion therapy, diagnostic performance of glutathione S-transferase-π (GST-π) and peroxiredoxin 1 (PRDX1): exploratory prospective multicentre study FLAG-1 protocol

INTRODUCTION

Plasma biomarkers may be useful in diagnosing acute cerebral infarction requiring urgent reperfusion, but their performance remains to be confirmed. If confirmed, these molecules could be used to develop rapid and reliable decentralised measurement methods, making it possible to initiate reperfusion therapy before hospital admission. The FLAG-1 large prospective study will constitute a plasma bank to assess the diagnostic performance of two biomarkers: glutathione S-transferase-π and peroxiredoxin 1. These molecules are involved in the oxidative stress response and could identify cerebral infarction within a therapeutic window of less than 4.5 hours following the onset of symptoms. Secondary objectives include assessing performance of these biomarkers within 3-hour and 6-hour windows; identifying additional biomarkers diagnosing cerebral infarction and significant criteria guiding therapeutic decisions: ischaemic features of stroke, presence of diffusion/fluid-attenuated inversion recovery mismatch, volume of cerebral infarction and penumbra on cerebral MRI.

METHODS AND ANALYSIS

The exploratory, prospective, multicentre FLAG-1 Study will include 945 patients with acute stroke symptoms (onset ≤12 hours, National Institute of Health Stroke Scale score ≥3). Each patient's 25 mL blood sample will be associated with cerebral MRI data. Two patient groups will be defined based on the time of blood collection (before and after 4.5 hours following onset). Receiver operating characteristic analysis will determine the diagnostic performance of each biomarker, alone or in combination, for the identification of cerebral infarction <4.5 hours.

ETHICS AND DISSEMINATION

The protocol has been approved by an independent ethics committee. Biological samples are retained in line with best practices and procedures, in accordance with French legislation. Anonymised data and cerebral imaging records are stored using electronic case report forms and a secure server, respectively, registered with the French Data Protection Authority (Commission Nationale de l'Informatique et des Libertés (CNIL)). Results will be disseminated through scientific meetings and publication in peer-reviewed medical journals.

TRIAL REGISTRATION NUMBER

ClinicalTrials.gov Registry (NCT03364296).

Ginsenoside Rg1 attenuates cerebral ischemia-reperfusion injury due to inhibition of NOX2-mediated calcium homeostasis dysregulation in mice

Background

The incidence of ischemic cerebrovascular disease is increasing in recent years and has been one of the leading causes of neurological dysfunction and death. Ginsenoside Rg1 has been found to protect against neuronal damage in many neurodegenerative diseases. However, the effect and mechanism by which Rg1 protects against cerebral ischemia-reperfusion injury (CIRI) are not fully understood. Here, we report the neuroprotective effects of Rg1 treatment on CIRI and its possible mechanisms in mice.

Methods

A bilateral common carotid artery ligation was used to establish a chronic CIRI model in mice. HT22 cells were treated with Rg1 after OGD/R to study its effect on [Ca²⁺]_i. The open-field test and pole-climbing experiment were used to detect behavioral injury. The laser speckle blood flowmeter was used to measure brain blood flow. The Nissl and H&E staining were used to examine the neuronal damage. The Western blotting was used to examine MAP2, PSD95, Tau, p-Tau, NOX2, PLC, p-PLC, CN, NFAT1, and NLRP1 expression. Calcium imaging was used to test the level of [Ca²⁺]_i.

Results

Rg1 treatment significantly improved cerebral blood flow, locomotion, and limb coordination, reduced ROS production, increased MAP2 and PSD95 expression, and decreased p-Tau, NOX2, p-PLC, CN, NFAT1, and NLRP1 expression. Calcium imaging results showed that Rg1 could inhibit calcium overload and resist the imbalance of calcium homeostasis after OGD/R in HT22 cells.

Conclusion

Rg1 plays a neuroprotective role in attenuating CIRI by inhibiting oxidative stress, calcium overload, and neuroinflammation.

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Rg1 ameliorates I/R-induced motor dysfunction and neuronal damage in mice.

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Rg1 decreases NOX2 expression and ROS accumulation in cerebral I/R mice.

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Rg1 inhibits calcium overload and CN-NFAT1 signaling in cerebral I/R mice.

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Rg1 down-regulates NLRP1 inflammasome in cerebral I/R mice.

Visualizing Oxidative Stress Level for Timely Assessment of Ischemic Stroke via a Ratiometric Near-Infrared-II Luminescent Nanoprobe

Ischemic stroke (IS) characterized with high morbidity and mortality rates is considered as one of the most dangerous brain diseases. The timely assessment of IS is crucial for making a clinical decision due to the severity of IS featured with time-dependence. Herein, we develop a highly reactive oxygen species (HROS)-responsive ratiometric near-infrared-II (NIR-II) nanoprobe based on a dye-sensitized system between IR-783 dye and lanthanide-doped nanoparticles. Once intravenously injected into the mice, the probe is rapidly accumulated at a lesion site by recognizing the activated endothelial cell or impaired blood-brain barrier (BBB) in the ischemic area and further responds to HROS, thereby allowing in vivo imaging of the oxidative stress level. The probe is not only able to discriminate the salvageable ischemic tissue from infarcted stroke core by visualizing the enriched degree of the probe at the lesion site but also can grade the salvageable ischemic tissue by analyzing the oxidative stress level. In addition, the ischemia area was clearly delineated by NIR-II luminescence imaging after cerebral ischemia for 30 min, which is significantly earlier than with the magnetic resonance imaging (MRI) method, thereby providing a practical tool for the timely assessing of IS.

Green tea and its active compound epigallocathechin-3-gallate (EGCG) inhibit neuronal apoptosis in a middle cerebral artery occlusion (MCAO) model

OBJECTIVES

To determine the effect of green tea with the active ingredient epigallocathechin-3-gallate (EGCG) on the inhibition of apoptosis in the middle cerebral artery occlusion (MCAO) model.

METHODS

Four month old male Rattus norvegicus rats with a body weight of 200-275 g was used for the MCAO model and divided into five groups, and the treatment was carried out for 7 days. Before being sacrificed, the subject had 1 cc of blood drawn for high mobility group box 1 (HMGB-1) examination using enzyme-linked immunosorbent assay (ELISA), and after being sacrificed, the brain tissue specimen was taken to examine caspase-3 and B-cell lymphoma 3 (BCL-3) using immunohistochemistry methods.

RESULTS

There was no significant difference in HMGB-1 results for the treatment group compared to the control group (P1: 384.20 ± 231.72 [p = 0.553]; P2: 379.11 ± 268.4 [p = 0.526]; P3: 284, 87 ± 276.19 [p = 0.140]; P4: 435.32 ± 279.95 [p = 0.912]). There is a significant increase in BCL-2 expression between the treatment group compared to the control group (P1: 2.58 ± 0.51 [p = 0.04]; P2: 3.36 ± 0.50 [p<0.001]; P3: 4.00 ± 0.42 [p<0.001]; P4: 3.60 ± 0.52 [p<0.001]). There was a significant difference in caspase-3 expression compared to the control group in the P3 group (P1: 4.33 ± 0.49 [p = 0.652]; P2: 4.09 ± 0.30 [p = 0.136]; P3: 3.58 ± 0.51 [p = 0.01]; P4: 3.89 ± 0.42 [p = 0.063]). There is no correlation between HMGB-1 and caspase-3 (r = -0.063; p = 0.613) or BCL-2 (r = -0.106; p = 0.396). There is significant negative correlation between caspase-3 and BCL-2 (r = -0.459; p = 0.000).

CONCLUSIONS

Green tea with the active ingredient EGCG can inhibit neuronal cell death through the apoptotic pathway and not through the activation of HMGB-1.

Salvianolate lyophilized injection regulates the autophagy-lysosomal pathway in cerebral ischaemia/reperfusion rats

ETHNOPHARMACOLOGICAL RELEVANCE

Activation of autophagy has been implicated in cerebral ischiemia/reperfusion (I/R) injury. Salvianolate lyophilized injection (SLI) has been widely used in the clinical treatment of cerebrovascular disease in China. Whether SLI has any influence on the activation of autophagy in cerebral I/R injury remains elusive.

AIM OF THE STUDY

The aim of this study were to assess whether SLI attenuates I/R-induced brain injury and evaluate its associated mechanisms.

MATERIALS AND METHODS

Focal cerebral ischaemia was induced by middle cerebral artery occlusion (MCAO). SLI (21 mg/kg) was injected intravenously at the beginning of the reperfusion period and 24 and 48 h after ischaemia. The effects of SLI on brain injury were detected according to infarct volume, neurological score, brain oedema, and HE and TUNEL staining at 72 h post-MCAO. Western blotting was used to detect alterations in the autophagy-relevant proteins LC3, Beclin-1, mTOR, p62, Lamp-1, and CTSD in the ipsilateral cortex at 24 or 72 h post-MCAO.

RESULTS

We first demonstrated that SLI significantly alleviated the infarct volume, neurological deficits, and brain oedema, and reduced the number of TUNEL-positive cells in rats with cerebral I/R injury. Next, we found that SLI has a bidirectional regulatory effect on autophagy: early-stage (24 h) cerebral ischaemia promotes the activation of autophagy and developmental-stage (72 h) cerebral ischaemia has an inhibitory effect. SLI enhanced I/R-induced autophagy as evidenced by the increased expression level of the autophagy marker protein LC3Ⅱ, as well as the decreased expression of mTOR and the autophagy substrate protein p62, but there was no change in lysosomal activity at 24 h after I/R-induced injury. Moreover, SLI also inhibited excessive activation of autophagy at 72 h after I/R-induced injury, which manifested as downregulating LC3Ⅱ expression, upregulating mTOR and p62 expression, and inhibiting lysosomal activity.

CONCLUSION

SLI has a protective effect on cerebral ischaemia/reperfusion injury, which may be mediated by the autophagy-lysosome pathway.

Knockdown of RMST Impedes Neuronal Apoptosis and Oxidative Stress in OGD/R-Induced Ischemic Stroke Via Depending on the miR-377/SEMA3A Signal Network

Long non-coding RNAs (lncRNAs) have pivotal roles in regulating ischemic stroke (IS), including lncRNA rhabdomyosarcoma 2-associated transcript (RMST). The purpose of this report is to discover the functional mechanism of RMST. The expression detection of RMST, microRNA-377 (miR-377) and Semaphorin 3A (SEMA3A) was performed by quantitative real-time polymerase chain reaction (qRT-PCR). Oxygen and glucose deprivation/reperfusion (OGD/R) in N2a cells was used to mimic IS environment in vitro. Cell Counting Kit-8 (CCK-8) and flow cytometry were implemented to assess cell viability and apoptosis. Oxidative stress was analyzed via assaying the associated indicators. Dual-luciferase reporter, RNA pull-down and RNA immunoprecipitation (RIP) assays were jointly administrated for binding analysis between targets. SEMA3A protein level was measured using western blot. We found in IS serum samples, RMST was upregulated while miR-377 was downregulated. After the establishment of OGD/R-induced IS model, we found that the decreased RMST abrogated the OGD/R-triggered apoptosis and oxidative stress. Through the target analysis, miR-377 was shown to be sponged by RMST and the effects of RMST knockdown on OGD/R-induced cell injuries were related to miR-377 upregulation. Besides, SEMA3A served as a target gene of miR-377 and the mitigation of miR-377 for ischemic brain damages was achieved by downregulating SEMA3A. What's more, RMST could regulate SEMA3A by playing the sponge action on miR-377. Collectively, all these findings clarified that RMST repression retarded IS progression in vitro via SEMA3A downregulation by targeting miR-377, which represented a different perspective in the pathological development of IS.

Coicis semen protects against focal cerebral ischemia-reperfusion injury by inhibiting oxidative stress and promoting angiogenesis via the TGFβ/ALK1/Smad1/5 signaling pathway

Background: Ischemic stroke is a devastating disease that causes long-term disability. However, its pathogenesis is unclear, and treatments for ischemic stroke are limited. Recent studies indicate that oxidative stress is involved in the pathological progression of ischemic stroke and that angiogenesis participates in recovery from ischemic stroke. Furthermore, previous studies have shown that Coicis Semen has antioxidative and anti-inflammatory effects in a variety of diseases. In the present study, we investigated whether Coicis Semen has a protective effect against ischemic stroke and the mechanism of this protective effect.

Results: Coicis Semen administration significantly decreased the infarct volume and mortality and alleviated neurological deficits at 3, 7 and 14 days after MCAO. In addition, cerebral edema at 3 days poststroke was ameliorated by Coicis Semen treatment. DHE staining showed that ROS levels in the vehicle group were increased at 3 days after reperfusion and then gradually declined, but Coicis Semen treatment reduced ROS levels. The levels of GSH and SOD in the brain were increased by Coicis Semen treatment, while MDA levels were reduced. Furthermore, Coicis Semen treatment decreased the extravasation of EB dye in MCAO mouse brains and elevated expression of the tight junction proteins ZO-1 and Occludin. Double immunofluorescence staining and western blot analysis showed that the expression of angiogenesis markers and TGFβ pathway-related proteins was increased by Coicis Semen administration. Consistent with the in vivo results, cytotoxicity assays showed that Coicis Semen substantially promoted HUVEC survival following OGD/RX in vitro. Additionally, though LY2109761 inhibited the activation of TGFβ signaling in OGD/RX model animals, Coicis Semen cotreatment markedly reversed the downregulation of TGFβ pathway-related proteins and increased VEGF levels.

Methods: Adult male wild-type C57BL/6J mice were used to develop a middle cerebral artery occlusion (MCAO) stroke model. Infarct size, neurological deficits and behavior were evaluated on days 3, 7 and 14 after staining. In addition, changes in superoxide dismutase (SOD), GSH and malondialdehyde (MDA) levels were detected with a commercial kit. Blood-brain barrier (BBB) permeability was assessed with Evans blue (EB) dye. Western blotting was also performed to measure the levels of tight junction proteins of the BBB. Additionally, ELISA was performed to measure the level of VEGF in the brain. The colocalization of CD31, angiogenesis markers, and Smad1/5 was assessed by double immunofluorescent staining. TGFβ pathway-related proteins were measured by western blotting. Furthermore, the cell viability of human umbilical vein endothelial cells (HUVECs) following oxygen-glucose deprivation/reoxygenation (OGD/RX) was measured by Cell Counting Kit (CCK)-8 assay.

Conclusions: Coicis Semen treatment alleviates brain damage induced by ischemic stroke through inhibiting oxidative stress and promoting angiogenesis by activating the TGFβ/ALK1 signaling pathway.

MAPK: A Key Player in the Development and Progression of Stroke

Conclusion:

Stroke is a complex disease caused by genetic and environmental factors, and its etiological mechanism has not been fully clarified yet, which brings great challenges to its effective prevention and treatment. MAPK signaling pathway regulates gene expression of eukaryotic cells and basic cellular processes such as cell proliferation, differentiation, migration, metabolism and apoptosis, which are considered as therapeutic targets for many diseases. Up to now, mounting evidence has shown that MAPK signaling pathway is involved in the pathogenesis and development of ischemic stroke. However, the upstream kinase and downstream kinase of MAPK signaling pathway are complex and the influencing factors are numerous, the exact role of MAPK signaling pathway in the pathogenesis of ischemic stroke has not been fully elucidated. MAPK signaling molecules in different cell types in the brain respond variously after stroke injury, therefore, the present review article is committed to summarizing the pathological process of different cell types participating in stroke, discussed the mechanism of MAPK participating in stroke. We further elucidated that MAPK signaling pathway molecules can be used as therapeutic targets for stroke, thus promoting the prevention and treatment of stroke.

Value of Blood-Based microRNAs in the Diagnosis of Acute Myocardial Infarction: A Systematic Review and Meta-Analysis

Background: Recent studies have shown that blood-based miRNAs are dysregulated in patients with acute myocardial infarction (AMI) and are therefore a potential tool for the diagnosis of AMI. Therefore, this study summarized and evaluated studies focused on microRNAs as novel biomarkers for the diagnosis of AMI from the last ten years. Methods: MEDLINE, the Cochrane Central database, and EMBASE were searched between January 2010 and December 2019. Studies that assessed the diagnostic accuracy of circulating microRNAs in AMI were chosen. The pooled sensitivity, specificity, positive likelihood ratio, negative likelihood ratio, diagnostic odds ratio, and area under the curve (AUC) were used to assess the test performance of miRNAs. Results: A total of 58 studies that included 8,206 participants assessed the diagnostic accuracy of circulating miRNAs in AMI. The main results of the meta-analyses are as follows: (1) Total miRNAs: the overall pooled sensitivity and specificity were 0.82 (95% CI: 0.79-0.85) and 0.87 (95% CI: 0.84-0.90), respectively. The AUC value was 0.91 (95% CI: 0.88-0.93) in the overall summary receiver operator characteristic (SROC) curve. (2) The panel of two miRNAs: sensitivity: 0.88 (95% CI: 0.77-0.94), specificity: 0.84 (95% CI: 0.72-0.91), AUC: 0.92 (95% CI: 0.90-0.94). (3) The panel of three miRNAs: sensitivity: 0.91 (95% CI: 0.85-0.94), specificity: 0.87 (95% CI: 0.77-0.92), AUC: 0.92 (95% CI: 0.89-0.94). (4) Results by types of miRNAs: miRNA-1: sensitivity: 0.78 (95% CI: 0.71-0.84), specificity: 0.86 (95% CI: 0.77-0.91), AUC: 0.88 (95% CI: 0.85-0.90); miRNA-133a: sensitivity: 0.85 (95% CI: 0.69-0.94), specificity: 0.92 (95% CI: 0.61-0.99), AUC: 0.93 (95% CI: 0.91-0.95); miRNA-208b: sensitivity: 0.80 (95% CI: 0.69-0.88), specificity: 0.96 (95% CI: 0.77-0.99), AUC: 0.91 (95% CI: 0.88-0.93); miRNA-499: sensitivity: 0.85 (95% CI: 0.77-0.91), specificity: 0.95 (95% CI: 0.89-0.98), AUC: 0.96 (95% CI: 0.94-0.97). Conclusion: miRNAs may be used as potential biomarkers for the detection of AMI. For single, stand-alone miRNAs, miRNA-499 may have better diagnostic accuracy compared to other miRNAs. We propose that a panel of multiple miRNAs with high sensitivity and specificity should be tested.

TREM-1-targeting LP17 attenuates cerebral ischemia-induced neuronal injury by inhibiting oxidative stress and pyroptosis

Stroke ranks as the second leading cause of disability and death globally. Trigger receptors expressed on myeloid cells (TREM) -1 are responsible for the activation of the innate immune response and also play a critical role in inflammation. In this study, we reported the contribution of TREM-1 after ischemic damage in a rat middle cerebral artery occlusion (MCAO) model. This study also demonstrated that TREM-1 expression was upregulated following cerebral infarction in rats. TREM-1 inhibition was determined using its selective inhibitor, LP17, which indicated a neuroprotective effect on cerebral infarction damage. The findings revealed that inhibition of TREM-1 by administering LP17 improved cerebral damage and decreased ischemic areas and brain water contents. Moreover, LP17 decreased MCAO-induced microglial activation and neurodegeneration, evidenced by a reduction in the expression of microglial Iba-1 and FJ-B positive cells, and reversed neuronal loss. Besides, the contribution of LP17 to ischemic neuronal damage may be associated with a decrease in the production of pro-inflammatory cytokines, and enhanced production of anti-inflammatory cytokine IL-10. Both in vivo and in vitro studies showed that inhibiting TREM-1 attenuated ROS accumulation, lipid per-oxidation (LPO) contents such as malondialdehyde (MDA) and enhanced the superoxide dismutase (SOD) activity after ischemia. Inhibiting TREM-1 alleviated inflammation and pyroptosis found in MCAO rats. This was achieved through the inhibition of the levels of NLRP3, caspase-1, ASC (an apoptosis-associated speck-like protein containing a CARD) and gasdermin D. These results confirmed that inhibiting TREM-1 protects against ischemia-induced neuronal damage and alleviates microglial mediated neuro-inflammation by reducing oxidative stress and pyroptosis. Therefore, blocking TREM-1 expression provides an effective intervention for improving ischemic stroke.

Oxidative Stress-Mediated Blood-Brain Barrier (BBB) Disruption in Neurological Diseases

The blood-brain barrier (BBB), as a crucial gate of brain-blood molecular exchange, is involved in the pathogenesis of multiple neurological diseases. Oxidative stress is caused by an imbalance between the production of reactive oxygen species (ROS) and the scavenger system. Since oxidative stress plays a significant role in the production and maintenance of the BBB, the cerebrovascular system is especially vulnerable to it. The pathways that initiate BBB dysfunction include, but are not limited to, mitochondrial dysfunction, excitotoxicity, iron metabolism, cytokines, pyroptosis, and necroptosis, all converging on the generation of ROS. Interestingly, ROS also provide common triggers that directly regulate BBB damage, parameters including tight junction (TJ) modifications, transporters, matrix metalloproteinase (MMP) activation, inflammatory responses, and autophagy. We will discuss the role of oxidative stress-mediated BBB disruption in neurological diseases, such as hemorrhagic stroke, ischemic stroke (IS), Alzheimer’s disease (AD), Parkinson’s disease (PD), traumatic brain injury (TBI), amyotrophic lateral sclerosis (ALS), and cerebral small vessel disease (CSVD). This review will also discuss the latest clinical evidence of potential biomarkers and antioxidant drugs towards oxidative stress in neurological diseases. A deeper understanding of how oxidative stress damages BBB may open up more therapeutic options for the treatment of neurological diseases.

Potential circadian effects on translational failure for neuroprotection

Neuroprotectant strategies that have worked in rodent models of stroke have failed to provide protection in clinical trials. Here we show that the opposite circadian cycles in nocturnal rodents versus diurnal humans^1,2 may contribute to this failure in translation. We tested three independent neuroprotective approaches-normobaric hyperoxia, the free radical scavenger α-phenyl-butyl-tert-nitrone (αPBN), and the N-methyl-D-aspartic acid (NMDA) antagonist MK801-in mouse and rat models of focal cerebral ischaemia. All three treatments reduced infarction in day-time (inactive phase) rodent models of stroke, but not in night-time (active phase) rodent models of stroke, which match the phase (active, day-time) during which most strokes occur in clinical trials. Laser-speckle imaging showed that the penumbra of cerebral ischaemia was narrower in the active-phase mouse model than in the inactive-phase model. The smaller penumbra was associated with a lower density of terminal deoxynucleotidyl transferase dUTP nick end labelling (TUNEL)-positive dying cells and reduced infarct growth from 12 to 72 h. When we induced circadian-like cycles in primary mouse neurons, deprivation of oxygen and glucose triggered a smaller release of glutamate and reactive oxygen species, as well as lower activation of apoptotic and necroptotic mediators, in 'active-phase' than in 'inactive-phase' rodent neurons. αPBN and MK801 reduced neuronal death only in 'inactive-phase' neurons. These findings suggest that the influence of circadian rhythm on neuroprotection must be considered for translational studies in stroke and central nervous system diseases.