Oxidative Stress Biomarkers of Brain Damage: Hyperacute Plasma F2-Isoprostane Predicts Infarct Growth in Stroke

The role of oxidative stress in blood-brain barrier disruption during ischemic stroke: Antioxidants in clinical trials

Ischemic stroke is one of the leading causes of death and disability. Occlusion and reperfusion of cerebral blood vessels (i.e., ischemia/reperfusion (I/R) injury) generates reactive oxygen species (ROS) that contribute to brain cell death and dysfunction of the blood-brain barrier (BBB) via oxidative stress. BBB disruption influences the pathogenesis of ischemic stroke by contributing to cerebral edema, hemorrhagic transformation, and extravasation of circulating neurotoxic proteins. An improved understanding of mechanisms for ROS-associated alterations in BBB function during ischemia/reperfusion (I/R) injury can lead to improved treatment paradigms for ischemic stroke. Unfortunately, progress in developing ROS targeted therapeutics that are effective for stroke treatment has been slow. Here, we review how ROS are produced in response to I/R injury, their effects on BBB integrity (i.e., tight junction protein complexes, transporters), and the utilization of antioxidant treatments in ischemic stroke clinical trials. Overall, knowledge in this area provides a strong translational framework for discovery of novel drugs for stroke and/or improved strategies to mitigate I/R injury in stroke patients.

Predictive value of serum MDA and 4-HNE levels on the occurrence of early neurological deterioration after intravenous thrombolysis with rt-PA IVT in patients with acute ischemic stroke

OBJECTIVE

This study investigated the predictive value of serum MDA and 4-HNE levels on early neurological deterioration (END) after recombinant tissue plasminogen activator (rt-PA) intravenous thrombolysis (IVT) in acute ischemic stroke (AIS) patients.

METHODS

This study analyzed 287 AIS patients with standard-dose rt-PA IVT. Clinical baseline and pathological data were recorded before rt-PA IVT, and neurologic deficit was assessed by NIHSS. AIS patients were classified into Non-END and END groups. Serum MDA and 4-HNE levels were determined by ELISA and their correlations with NIHSS scores were evaluated. AIS patients were allocated into groups with high and low MDA or 4-HNE expression, and post-IVT END incidence was compared. Independent risk indexes for post-IVT END and the predictive value of serum MDA+4-HNE levels on post-IVT END were assessed.

RESULTS

Serum MDA and 4-HNE were higher in AIS patients with post-IVT END. NIHSS score showed a positive correlation with serum MDA and 4-HNE levels. MDA levels were positively correlated with 4-HNE levels in AIS patients. END after IVT was increased in AIS patients with high MDA/4-HNE expression. FBG, lymphocyte percentage, PLR, NIHSS score, serum MDA, and 4-HNE levels were independent risk factors for END after IVT. The diagnostic efficacy of MDA+4-HNE in assessing post-IVT END in AIS patients (sensitivity 92.00 %, specificity 82.70 %) was higher than MDA or 4-HNE alone.

CONCLUSION

Serum MDA and 4-HNE levels were higher in AIS patients with post-IVT END than in those with non-END, and MDA+4-HNE possessed a higher predictive value for post-IVT END in AIS patients.

Blood-based biomarkers of cerebral small vessel disease

Age-associated cerebral small vessel disease (CSVD) represents a clinically heterogenous condition, arising from diverse microvascular mechanisms. These lead to chronic cerebrovascular dysfunction and carry a substantial risk of subsequent stroke and vascular cognitive impairment in aging populations. Owing to advances in neuroimaging, in vivo visualization of cerebral vasculature abnormities and detection of CSVD, including lacunes, microinfarcts, microbleeds and white matter lesions, is now possible, but remains a resource-, skills- and time-intensive approach. As a result, there has been a recent proliferation of blood-based biomarker studies for CSVD aimed at developing accessible screening tools for early detection and risk stratification. However, a good understanding of the pathophysiological processes underpinning CSVD is needed to identify and assess clinically useful biomarkers. Here, we provide an overview of processes associated with CSVD pathogenesis, including endothelial injury and dysfunction, neuroinflammation, oxidative stress, perivascular neuronal damage as well as cardiovascular dysfunction. Then, we review clinical studies of the key biomolecules involved in the aforementioned processes. Lastly, we outline future trends and directions for CSVD biomarker discovery and clinical validation.

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.

In Mild and Moderate Acute Ischemic Stroke, Increased Lipid Peroxidation and Lowered Antioxidant Defenses Are Strongly Associated with Disabilities and Final Stroke Core Volume

In acute ischemic stroke (AIS), there are no data on whether oxidative stress biomarkers have effects above and beyond known risk factors and measurements of stroke volume. This study was conducted in 122 mild-moderate AIS patients and 40 controls and assessed the modified ranking scale (mRS) at baseline, and 3 and 6 months later. We measured lipid hydroperoxides (LOOH), malondialdehyde (MDA), advanced oxidation protein products, paraoxonase 1 (PON1) activities and PON1 Q192R genotypes, high density lipoprotein cholesterol (HDL), sulfhydryl (-SH) groups), and diffusion-weighted imaging (DWI) stroke volume and fluid-attenuated inversion recovery (FLAIR) signal intensity. We found that (a) AIS is characterized by lower chloromethyl acetate CMPAase PON1 activity, HDL and -SH groups and increased LOOH and neurotoxicity (a composite of LOOH, inflammatory markers and glycated hemoglobin); (b) oxidative and antioxidant biomarkers strongly and independently predict mRS scores 3 and 6 months later, DWI stroke volume and FLAIR signal intensity; and (c) the PON1 Q192R variant has multiple effects on stroke outcomes that are mediated by its effects on antioxidant defenses and lipid peroxidation. Lipid peroxidation and lowered -SH and PON1-HDL activity are drug targets to prevent AIS and consequent neurodegenerative processes and increased oxidative reperfusion mediators due to ischemia-reperfusion injury.

The Role of the Thioredoxin System in Brain Diseases

The thioredoxin system, consisting of thioredoxin (Trx), thioredoxin reductase (TrxR), and NADPH, plays a fundamental role in the control of antioxidant defenses, cell proliferation, redox states, and apoptosis. Aberrations in the Trx system may lead to increased oxidative stress toxicity and neurodegenerative processes. This study reviews the role of the Trx system in the pathophysiology and treatment of Alzheimer's, Parkinson's and Huntington's diseases, brain stroke, and multiple sclerosis. Trx system plays an important role in the pathophysiology of those disorders via multiple interactions through oxidative stress, apoptotic, neuro-immune, and pro-survival pathways. Multiple aberrations in Trx and TrxR systems related to other redox systems and their multiple reciprocal relationships with the neurodegenerative, neuro-inflammatory, and neuro-oxidative pathways are here analyzed. Genetic and environmental factors (nutrition, metals, and toxins) may impact the function of the Trx system, thereby contributing to neuropsychiatric disease. Aberrations in the Trx and TrxR systems could be a promising drug target to prevent and treat neurodegenerative, neuro-inflammatory, neuro-oxidative stress processes, and related brain disorders.

Oxidative Stress and Inflammation Markers Associated with Multiple Peripheral Artery Occlusions in Elderly Patients

Background: Pro-oxidative stress and pro-inflammatory responses can influence each other in the development of atherosclerosis. This study evaluated the relationship between oxidative stress, inflammation, and multiple peripheral artery occlusions in elderly patients (age mean 71.2 ± 8.1 years). Methods: A total of 723 participants were enrolled: 67 healthy subjects, 214 patients with common iliac artery occlusions, 224 patients with popliteal artery occlusions, and 218 patients with femoral artery occlusions. We measured oxidative stress biomarkers (malondialdehyde [MDA], F2-isoprostane [F2-isoP], total oxidant status [TOS], and ischemia-modified albumin [IMA]) and the expressions of molecules in mimecan (MIME)/nuclear factor kappa B (NF-κB)/P53/Toll-like receptor 4 (TLR4) signaling pathway in older patients with multiple peripheral artery occlusions. Results: The levels of MDA, F2-isoP, TOS, IMA, MIME, NF-κB, P53, and TLR4 were increased in the single-site peripheral artery occlusive group when compared with healthy controls (P < .001) and were further increased in the multiple-site peripheral artery occlusive group compared with the single-site peripheral artery occlusive group (P < .001). Conclusion: Oxidative stress may promote inflammatory signaling pathways and lead to multiple peripheral artery occlusions in elderly patients.

A Systematic Review of Body Fluids Biomarkers Associated With Early Neurological Deterioration Following Acute Ischemic Stroke

Biomarkers are objectively measured biological properties of normal and pathological processes. Early neurological deterioration (END) refers to the deterioration of neurological function in a short time after the onset of acute ischemic stroke (AIS) and is associated with adverse outcomes. Although multiple biomarkers have been found to predict END, there are currently no suitable biomarkers to be applied in routine stroke care. According to the Preferred Reporting Items for Systematic Review standards, we present a systematic review, concentrating on body fluids biomarkers that have shown potential to be transferred into clinical practice. We also describe newly reported body fluids biomarkers that can supply different insights into the mechanism of END. In our review, 40 scientific papers were included. Depending on the various mechanisms, sources or physicochemical characteristics of body fluids biomarkers, we classified related biomarkers as inflammation, protease, coagulation, metabolism, oxidative stress, and excitatory neurotoxicity. The body fluids biomarkers whose related articles are limited or mechanisms are unknown are categorized as other biomarkers. The inflammation-related biomarkers, such as neutrophil-to-lymphocyte ratio and hypersensitive C-reactive protein, play a crucial role among the mentioned biomarkers. Considering the vast heterogeneity of stroke progression, using a single body fluids biomarker may not accurately predict the risk of stroke progression, and it is necessary to combine multiple biomarkers (panels, scores, or indices) to improve their capacity to estimate END.

Endoplasmic Reticulum Stress and the Unfolded Protein Response in Cerebral Ischemia/Reperfusion Injury

Ischemic stroke is an acute cerebrovascular disease characterized by sudden interruption of blood flow in a certain part of the brain, leading to serious disability and death. At present, treatment methods for ischemic stroke are limited to thrombolysis or thrombus removal, but the treatment window is very narrow. However, recovery of cerebral blood circulation further causes cerebral ischemia/reperfusion injury (CIRI). The endoplasmic reticulum (ER) plays an important role in protein secretion, membrane protein folding, transportation, and maintenance of intracellular calcium homeostasis. Endoplasmic reticulum stress (ERS) plays a crucial role in cerebral ischemia pathophysiology. Mild ERS helps improve cell tolerance and restore cell homeostasis; however, excessive or long-term ERS causes apoptotic pathway activation. Specifically, the protein kinase R-like endoplasmic reticulum kinase (PERK), activating transcription factor 6 (ATF6), and inositol-requiring enzyme 1 (IRE1) pathways are significantly activated following initiation of the unfolded protein response (UPR). CIRI-induced apoptosis leads to nerve cell death, which ultimately aggravates neurological deficits in patients. Therefore, it is necessary and important to comprehensively explore the mechanism of ERS in CIRI to identify methods for preserving brain cells and neuronal function after ischemia.

FAST-IT: Find A Simple Test - In TIA (transient ischaemic attack): a prospective cohort study to develop a multivariable prediction model for diagnosis of TIA through proteomic discovery and candidate lipid mass spectrometry, neuroimaging and machine learning-study protocol

INTRODUCTION

Transient ischaemic attack (TIA) may be a warning sign of stroke and difficult to differentiate from minor stroke and TIA-mimics. Urgent evaluation and diagnosis is important as treating TIA early can prevent subsequent strokes. Recent improvements in mass spectrometer technology allow quantification of hundreds of plasma proteins and lipids, yielding large datasets that would benefit from different approaches including machine learning. Using plasma protein, lipid and radiological biomarkers, our study will develop predictive algorithms to distinguish TIA from minor stroke (positive control) and TIA-mimics (negative control). Analysis including machine learning employs more sophisticated modelling, allowing non-linear interactions, adapting to datasets and enabling development of multiple specialised test-panels for identification and differentiation.

METHODS AND ANALYSIS

Patients attending the Emergency Department, Stroke Ward or TIA Clinic at the Royal Adelaide Hospital with TIA, minor stroke or TIA-like symptoms will be recruited consecutively by staff-alert for this prospective cohort study. Advanced neuroimaging will be performed for each participant, with images assessed independently by up to three expert neurologists. Venous blood samples will be collected within 48 hours of symptom onset. Plasma proteomic and lipid analysis will use advanced mass spectrometry (MS) techniques. Principal component analysis and hierarchical cluster analysis will be performed using MS software. Output files will be analysed for relative biomarker quantitative differences between the three groups. Differences will be assessed by linear regression, one-way analysis of variance, Kruskal-Wallis H-test, χ² test or Fisher's exact test. Machine learning methods will also be applied including deep learning using neural networks.

ETHICS AND DISSEMINATION

Patients will provide written informed consent to participate in this grant-funded study. The Central Adelaide Local Health Network Human Research Ethics Committee approved this study (HREC/18/CALHN/384; R20180618). Findings will be disseminated through peer-reviewed publication and conferences; data will be managed according to our Data Management Plan (DMP2020-00062).

Antioxidant Therapy in Oxidative Stress-Induced Neurodegenerative Diseases: Role of Nanoparticle-Based Drug Delivery Systems in Clinical Translation

Free radicals are formed as a part of normal metabolic activities but are neutralized by the endogenous antioxidants present in cells/tissue, thus maintaining the redox balance. This redox balance is disrupted in certain neuropathophysiological conditions, causing oxidative stress, which is implicated in several progressive neurodegenerative diseases. Following neuronal injury, secondary injury progression is also caused by excessive production of free radicals. Highly reactive free radicals, mainly the reactive oxygen species (ROS) and reactive nitrogen species (RNS), damage the cell membrane, proteins, and DNA, which triggers a self-propagating inflammatory cascade of degenerative events. Dysfunctional mitochondria under oxidative stress conditions are considered a key mediator in progressive neurodegeneration. Exogenous delivery of antioxidants holds promise to alleviate oxidative stress to regain the redox balance. In this regard, natural and synthetic antioxidants have been evaluated. Despite promising results in preclinical studies, clinical translation of antioxidants as a therapy to treat neurodegenerative diseases remains elusive. The issues could be their low bioavailability, instability, limited transport to the target tissue, and/or poor antioxidant capacity, requiring repeated and high dosing, which cannot be administered to humans because of dose-limiting toxicity. Our laboratory is investigating nanoparticle-mediated delivery of antioxidant enzymes to address some of the above issues. Apart from being endogenous, the main advantage of antioxidant enzymes is their catalytic mechanism of action; hence, they are significantly more effective at lower doses in detoxifying the deleterious effects of free radicals than nonenzymatic antioxidants. This review provides a comprehensive analysis of the potential of antioxidant therapy, challenges in their clinical translation, and the role nanoparticles/drug delivery systems could play in addressing these challenges.

Research Progress on the Pharmacological Action of Schisantherin A

Schisantherin A (Sch A) is a dibenzocyclooctadiene lignan monomer isolated from the fruit of Schisandra chinensis (Turcz.) Baill. (S. chinensis). At present, many studies have shown that Sch A has a wide range of pharmacological effects, including its anti-Parkinson and anti-inflammatory effects and ability to protect the liver, protect against ischemia-reperfusion (I/R) injury, suppress osteoclast formation, and improve learning and memory. Its mechanism may be related to the antioxidant, anti-inflammatory, and antiapoptotic properties of Sch A through the MAPK, NF-κB, AKT/GSK3β, and PI3K/AKT pathways. This is the first review of the recent studies on the pharmacological mechanism of Sch A.

Isoprostanoid Plasma Levels Are Relevant to Cerebral Adrenoleukodystrophy Disease

Cerebral adrenoleukodystrophy (ALD) is a rare neuroinflammatory disorder characterized by progressive demyelination. Mutations within the ABCD1 gene result in very long-chain fatty acid (VLCFA) accumulation within the peroxisome, particularly in the brain. While this VLCFA accumulation is known to be the driving cause of the disease, oxidative stress can be a contributing factor. For patients with early cerebral disease, allogeneic hematopoietic stem cell transplantation (HSCT) is the standard of care, and this can be supported by antioxidants. To evaluate the involvement of fatty acid oxidation in the disease, F2-isoprostanes (F2-IsoPs), F2-dihomo-isoprostanes (F2-dihomo-IsoPs) and F4-neuroprostanes (F4-NeuroPs)-which are oxygenated metabolites of arachidonic (ARA), adrenic (AdA) and docosahexaenoic (DHA) acids, respectively-in plasma samples from ALD subjects (n = 20)-with various phenotypes of the disease-were measured. Three ALD groups were classified according to patients with: (1) confirmed diagnosis of ALD but without cerebral disease; (2) cerebral disease in early period post-HSCT (<100 days post-HSCT) and on intravenous N-acetyl-L-cysteine (NAC) treatment; (3) cerebral disease in late period post-HSCT (beyond 100 days post-HSCT) and off NAC therapy. In our observation, when compared to healthy subjects (n = 29), in ALD (i), F2-IsoPs levels were significantly (p < 0.01) increased in all patients, with the single exception of the early ALD and on NAC subjects; (ii) significant elevated (p < 0.0001) amounts of F2-dihomo-IsoPs were detected, with the exception of patients with a lack of cerebral disease; (iii), a significant increase (p < 0.003) in F4-NeuroP plasma levels was detected in all ALD patients. Moreover, F2-IsoPs plasma levels were significantly higher (p = 0.038) in early ALD in comparison to late ALD stage, and F4-NeuroPs were significantly lower (p = 0.012) in ALD subjects with a lack of cerebral disease in comparison to the late disease stage. Remarkably, plasma amounts of all investigated isoprostanoids were shown to discriminate ALD patients vs. healthy subjects. Altogether, isoprostanoids are relevant to the phenotype of X-ALD and may be helpful in predicting the presence of cerebral disease and establishing the risk of progression.

Association Between Plasma Redox State/Mitochondria Function and a Flu-Like Syndrome/COVID-19 in the Elderly Admitted to a Long-Term Care Unit

Background/Aims: It is widely known that the imbalance between reactive oxygen species (ROS)/antioxidants and mitochondrial function could play a pivotal role in aging and in the physiopathology of viral infections. Here, we correlated the plasma oxidants/antioxidants levels of the elderly admitted to a long-term care (LTC) unit with clinical data in relation to flu-like disease/COVID-19. Moreover, in vitro we examined the effects of plasma on cell viability, ROS release and mitochondrial function. Materials and Methods: In 60 patients admitted to LTC unit for at least 1 year at moderate or high care load, demographic and clinical variables were taken. Blood samples were collected for the evaluations of oxidants/antioxidants, as thiobarbituric acid reactive substances, 8-hydroxy-2-deoxyguanosine, 8-isoprostanes, superoxide dismutase activity, glutathione, and vitamin D. In vitro, human umbilical vascular endothelial cells (HUVEC) were used to examine the effects of plasma on viability, ROS release and mitochondrial membrane potential. Results: The results obtained showed that the redox state of the elderly was quite balanced; mitochondrial membrane potential of HUVEC was reduced by about 20%, only. Also, the correlation analysis evidenced the association between mitochondrial function and the patients' outcomes. Interestingly, lower levels of mitochondrial membrane potential were found in the elderly who had symptoms suggestive of COVID-19 or with a confirmed diagnosis of COVID-19. Conclusion: The results of this study highlight the importance of mitochondrial function in the tendency to get a flu-like syndrome like COVID-19 in the elderly admitted to LTC unit. This information could have clinical implications for the management of old population.

Oleuropein Protects Against Cerebral Ischemia Injury in Rats: Molecular Docking, Biochemical and Histological Findings

This study was designed to evaluate the underlying protective mechanisms of oleuropein involved in alleviating brain damage in a rat model of ischemic stroke. Male Wistar rats were divided into four groups; Control, stroke (MCAO), MCAO + clopidogrel (Clop) and MCAO + oleuropein (Ole). Results showed that the MCAO group evidenced significant brain edema (+ 9%) as well as increases of plasma cardiac markers such as lactate deshydrogenase (LDH), creatine kinase (CK-MB), fibrinogen and Trop-T by 11 %, 43%, 168 and 590%, respectively, as compared to the control group. Moreover, infarcted rats exhibited remarkable elevated levels of angiotensin converting enzyme (ACE), both in plasma and brain tissue, with astrocyte swelling and necrotic neurons in the infarct zone, hyponatremia, and increased rate of thiobarbituric acid-reactive substances (TBARS) by 89% associated with decreases in the activity of superoxide dismutase (SOD), glutathione peroxidase (GPx) and catalase (Cat) by 51%, 44 and 42%, respectively, compared to normal control rats. However, MCAO rats treated with oleuropein underwent mitigation of cerebral edema, correction of hyponatremia, remarkable decrease of plasma fibrinogen and cardiac dysfunctional enzymes, inhibition of ACE activity and improvement of oxidative stress status in brain tissue. Furthermore, in silico analysis showed considerable inhibitions of ACE, protein disulfide isomerase (PDI) and TGF-β1, an indicative of potent anti-embolic properties. Overall, oleuropein offers a neuroprotective effect against ischemic stroke through its antioxidative and antithrombotic activities.

Astaxanthin attenuates acute cerebral infarction via Nrf-2/HO-1 pathway in rats

OBJECTIVE

Acute cerebral infarction (ACI) is susceptible to cause disability or death of people. Astaxanthin (ATX) possesses the protective effect of organ injury. Therefore, the study was to explore the potential mechanism of protective effect with ATX on ACI.

METHODS

30 SD rats were divided into Sham, ACI, and ATX groups. The rats in the ATX group were pretreated with ATX by gavage for three days before surgery, while the rats in the other two groups were pretreated with saline. The model of ACI was established by thread embolization. 24 h after the operation, the neurological function was scored, and cerebral infarct area and pathological morphology of brains were measured; the edema of the brain was detected by dry/wet method; Western blot was applied to measure the translocation of Nrf-2 and the protein expression of HO-1, Bax and BCL-2; Brain cell apoptosis was assessed through TUNEL; ELISA was used to detect the oxidative stress factors of catalase (CAT) superoxide dismutase (SOD), glutathione peroxidase (GPX) and malondialdehyde (MDA), and the inflammatory factors of TNF-α, IL-1β, IL-6.

RESULT

Compared with the ACI group, ATX pretreatment can significantly improve neurological function; reduce the edema index of the brain, cerebral infarct area, cerebral pathological damage and apoptosis of brain cells. Moreover, ATX also can increase the protein expression of nuclear Nrf-2, HO-1, BCL-2, CAT, SOD, and GPX by decreasing the content of TNF-α, IL-1β, IL-6, MDA, Bax and cytosolic Nrf-2.

CONCLUSION

ATX might have a protective effect of acute cerebral infarction, and the mechanism is probably associated with suppressing oxidative stress, inflammation, and apoptosis by activating Nrf-2/HO-1signalling.

Serum Sphingosine 1-Phosphate (S1P): A Novel Diagnostic Biomarker in Early Acute Ischemic Stroke

Background: Sphingosine 1-phosphate (S1P) is a lipid metabolite that mediates various physiological processes, including vascular endothelial cell function, inflammation, coagulation/thrombosis, and angiogenesis. As a result, S1P may contribute to the pathogenesis of stroke.

Objective: This study aimed to evaluate the diagnostic value of serum S1P in acute stroke.

Method: A total of 72 patients with ischemic stroke, 36 patients with hemorrhagic stroke, and 65 controls were enrolled. Serum S1P was detected by enzyme-linked immunosorbent assay (ELISA).

Results: Receiver operating characteristic curve analysis demonstrated that serum S1P could discriminate ischemic stroke from hemorrhagic stroke in both total population and subgroup analyses of samples obtained within 24 h of symptom onset (subgroup _{< 24h}) (area under curve, AUC_Total = 0.64, P = 0.017; AUC_{Subgroup < 24h} = 0.91, P < 0.001) and controls (AUC_Total = 0.62, P = 0.013; AUC_{Subgroup <24h} = 0.83, P < 0.001). Furthermore, S1P showed higher efficacy than high-density lipoprotein cholesterol (HDL-C) in discriminating ischemic stroke from controls in the total population (P_S1P = 0.013, P_HDL−C = 0.366) and in the subgroup analysis (i.e., <24 h; P_S1P < 0.001, P_HDL−C = 0.081). Additionally, lower serum S1P was associated with cervical artery plaques (P = 0.021) in controls and with dyslipidemia (P = 0.036) and milder neurological impairment evaluated by the National Institute of Health Stroke Scale (NIHSS, P = 0.047) in the ischemic stroke group.

Conclusions: The present study preliminarily investigated the diagnostic value of serum S1P in acute stroke. Decreased serum S1P may become a potential biomarker for early acute ischemic stroke and can indicate disease severity.

Plasma endothelial microvesicles and their carrying miRNA-155 serve as biomarkers for ischemic stroke

Endothelial microvesicles (EMVs) could reflect the status of endothelial cells (ECs) which are involved in the pathogenesis of ischemic stroke (IS). MiR-155 could regulate EC functions. However, their roles in IS remain unclear. This study aimed to investigate the levels of plasma EMVs and EMVs carrying miRNA-155 (EMVs-miR-155) in IS patients to explore their potential roles as biomarkers. Ninety-three IS patients and 70 controls were recruited in this study. The levels of circulating EMVs and EMVs-miR-155 were detected by fluorescence nanoparticle tracking analysis and quantitative real-time PCR, respectively. The correlations between level of EMVs/EMVs-miR-155 and the onset time, severity, infarct volume, and subtypes of IS were analyzed. The severity and infarct volume were assessed by NIHSS and magnetic resonance imaging, respectively. Multivariate logistic regression analysis was used to investigate the risk factors of IS. The ROC curve and area under ROC curve (AUC) of EMVs and EMVs-miR-155 were determined. The levels of plasma EMVs and EMVs-miR-155 were increased significantly in acute and subacute stages of IS and remained unchanged in chronic stage, and were positively related to the infarct volume and NIHSS scores and were associated with large artery atherosclerosis and cardioembolism subtypes defined by Trial of Org 10 172 in acute stroke treatment (TOAST) classification. Multivariate logistic regression analysis demonstrated that plasma EMVs and EMVs-miR-155 were significant and independent risk factors of IS and their AUC were 0.778 and 0.851, respectively, and increased to 0.892 after combination. Our study suggests that plasma EMVs and EMVs-miR-155 are promising biomarkers for IS. The diagnostic value of EMVs-miR-155 is higher and their combination is the best.

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.

Serum levels of superoxide dismutases in patients with benign paroxysmal positional vertigo

Objective: To investigate the possible role of superoxide dismutases (SODs) in the development of benign paroxysmal positional vertigo (BPPV) and recurrence events in a 1-year follow-up study.

Methods: This was a prospective one-center study. A total of 204 patients with BPPV and 120 age-and sex matched healthy subjects were included. The levels of SOD between patients and control cases were compared. The levels of SOD between posterior semicircular canal (PSC) and horizontal semicircular canal (HSC) were also compared. In the 1-year follow-up, recurrence events were confirmed. The influence of SOD levels on BPPV and recurrent BPPV were performed by binary logistic regression analysis.

Results: The serum levels of SOD in patients with BPPV were lower than in those control cases (P<0.001). Levels of SOD did not differ in patients with PSC and HSC (P=0.42). As a categorical variable, for per interquartile range (IQR) increment of serum level of SOD, the unadjusted and adjusted risks of BPPV would be decreased by 72% (with the odds ratio [OR] of 0.28 [95% confidence interval (CI): 0.21–0.37], P<0.001) and 43% (0.57 [0.42–0.69], P<0.001), respectively. Recurrent attacks of BPPV were reported in 50 patients (24.5%). Patients with recurrent BPPV had lower levels of SOD than in patients without (P<0.001). For per IQR increment of serum level of SOD, the unadjusted and adjusted risks of BPPV would be decreased by 51% (with the OR of 0.49 [95% CI: 0.36–0.68], P<0.001) and 24% (0.76 [0.60–0.83], P<0.001), respectively.

Conclusion: Reduced serum levels of SOD were associated with higher risk of BPPV and BPPV recurrence events.

Mitochondrial damage & lipid signaling in traumatic brain injury

Mitochondria are essential for neuronal function because they serve not only to sustain energy and redox homeostasis but also are harbingers of death. A dysregulated mitochondrial network can cascade until function is irreparably lost, dooming cells. TBI is most prevalent in the young and comes at significant personal and societal costs. Traumatic brain injury (TBI) triggers a biphasic and mechanistically heterogenous response and this mechanistic heterogeneity has made the development of standardized treatments challenging. The secondary phase of TBI injury evolves over hours and days after the initial insult, providing a window of opportunity for intervention. However, no FDA approved treatment for neuroprotection after TBI currently exists. With recent advances in detection techniques, there has been increasing recognition of the significance and roles of mitochondrial redox lipid signaling in both acute and chronic central nervous system (CNS) pathologies. Oxidized lipids and their downstream products result from and contribute to TBI pathogenesis. Therapies targeting the mitochondrial lipid composition and redox state show promise in experimental TBI and warrant further exploration. In this review, we provide 1) an overview for mitochondrial redox homeostasis with emphasis on glutathione metabolism, 2) the key mechanisms of TBI mitochondrial injury, 3) the pathways of mitochondria specific phospholipid cardiolipin oxidation, and 4) review the mechanisms of mitochondria quality control in TBI with consideration of the roles lipids play in this process.

Silencing of TXNIP Alleviated Oxidative Stress Injury by Regulating MAPK-Nrf2 Axis in Ischemic Stroke

Ischemic stroke is a life-threatening cerebrovascular thrombotic disease, oxidative stress is considered to be a critical factor to stroke pathophysiology. This study aimed to investigate the underlying molecular mechanism and propose the potential therapeutic strategy for ischemic stroke. Bioinformatics analysis based on a public microarray profile (GSE 61616) of ischemic stroke rats was performed as a pilot research. Oxidative stress was enriched as a significantly gene ontology item, and thioredoxin-interacting protein (TXNIP) and MAPK signaling were identified as the hub gene and pathway, respectively. The experiments in middle cerebral artery occlusion rats demonstrated that ischemia induced the activation of oxidative stress. The expressions of TXNIP, p-p38, p-JNK, p-ERK were significantly increased while Nrf2 and HO-1 expressions were decreased after stroke. Rescue assays were conducted in primary cultured neurons to explore the accurate interrelations among these factors. The results indicated that MAPK specific inhibitor and siRNA-TXNIP significantly alleviated the oxidative stress injury induced by oxygen-glucose deprivation. In addition, knocking down of TXNIP inhibited the activation of MAPK pathway and promoted Nrf2 pathway. Taken together, these findings indicated that TXNIP aggravated the oxidative stress injury by regulating MAPK-Nrf2 axis in ischemic stroke. Silencing of TXNIP seems a promising therapeutic strategy to alleviate ischemic stroke.

Sex-specific differences in white matter microvascular integrity after ischaemic stroke

Background and purpose

Functional outcomes after ischaemic stroke are worse in women, despite adjusting for differences in comorbidities and treatment approaches. White matter microvascular integrity represents one risk factor for poor long-term functional outcomes after ischaemic stroke. The aim of the study is to characterise sex-specific differences in microvascular integrity in individuals with acute ischaemic stroke.

Methods

A retrospective analysis of subjects with acute ischaemic stroke and brain MRI with diffusion-weighted (DWI) and dynamic-susceptibility contrast-enhanced (DSC) perfusion-weighted imaging obtained within 9 hours of last known well was performed. In the hemisphere contralateral to the acute infarct, normal-appearing white matter (NAWM) microvascular integrity was measured using the K₂ coefficient and apparent diffusion coefficient (ADC) values. Regression analyses for predictors of K₂ coefficient, DWI volume and good outcome (90-day modified Rankin scale (mRS) score <2) were performed.

Results

105 men and 79 women met inclusion criteria for analysis. Despite no difference in age, women had increased NAWM K₂ coefficient (1027.4 vs 692.7×10^–6/s; p=0.006). In women, atrial fibrillation (β=583.6; p=0.04) and increasing NAWM ADC (β=4.4; p=0.02) were associated with increased NAWM K₂ coefficient. In multivariable regression analysis, the K₂ coefficient was an independent predictor of DWI volume in women (β=0.007; p=0.01) but not men.

Conclusions

In women with acute ischaemic stroke, increased NAWM K₂ coefficient is associated with increased infarct volume and chronic white matter structural integrity. Prospective studies investigating sex-specific differences in white matter microvascular integrity are needed.

Early molecular oxidative stress biomarkers of ischemic penumbra in acute stroke

OBJECTIVES

To assess whether plasma biomarkers of oxidative stress predict diffusion-perfusion mismatch in patients with acute ischemic stroke (AIS).

METHODS

We measured plasma levels of oxidative stress biomarkers such as F2-isoprostanes (F2-isoPs), total and perchloric acid Oxygen Radical Absorbance Capacity (ORAC_TOT and ORAC_PCA), urinary levels of 8-oxo-7,8-dihydro-2'-deoxyguoanosine, and inflammatory and tissue-damage biomarkers (high-sensitivity C-reactive protein, matrix metalloproteinase-2 and -9) in a prospective study of patients with AIS presenting within 9 hours of symptom onset. Diffusion-weighted (DWI) and perfusion-weighted (PWI) MRI sequences were analyzed with a semiautomated volumetric method. Mismatch was defined as baseline mean transit time volume minus DWI volume. A percent mismatch cutoff of >20% was considered clinically significant. A stricter definition of mismatch was also used. Mismatch salvage was the region free of overlap by final infarction.

RESULTS

Mismatch >20% was present in 153 of 216 (70.8%) patients (mean [±SD] age 69.2 ± 14.3 years, 41.2% women). Patients with mismatch >20% were more likely to have higher baseline plasma levels of ORAC_PCA (p = 0.020) and F2-isoPs (p = 0.145). Multivariate binary logistic regression demonstrated that lnF2-isoP (odds ratio [OR] 2.44, 95% confidence interval [CI] 1.19-4.98, p = 0.014) and lnORAC_PCA (OR 4.18, 95% CI 1.41-12.41, p = 0.010) were independent predictors of >20% PWI-DWI mismatch and the stricter mismatch definition, respectively. lnORAC_TOT significantly predicted mismatch salvage volume (>20% mismatch p = 0.010, stricter mismatch definition p = 0.003).

CONCLUSIONS

Elevated hyperacute plasma levels of F2-isoP and ORAC are associated with radiographic evidence of mismatch and mismatch salvage in patients with AIS. If validated, these findings may add to our understanding of the role of oxidative stress in cerebral tissue fate during acute ischemia.

Hemorrhage simulated by lower body negative pressure provokes an oxidative stress response in healthy young adults

IMPACT STATEMENT

We characterize the systemic oxidative stress response in young, healthy human subjects with exposure to simulated hemorrhage via application of lower body negative pressure (LBNP). Prior work has demonstrated that LBNP and actual blood loss evoke similar hemodynamic and immune responses (i.e. white blood cell count), but it is unknown whether LBNP elicits oxidative stress resembling that produced by blood loss. We show that LBNP induces a 29% increase in F₂-isoprostanes, a systemic marker of oxidative stress. The findings of this investigation may have important implications for the study of hemorrhage using LBNP, including future assessments of targeted interventions that may reduce oxidative stress, such as novel fluid resuscitation approaches.

Relationship between short telomere length and stroke: A meta-analysis

BACKGROUND

Several epidemiological studies had been carried out in different population cohorts to estimate the relationship between the shortened telomere length and stroke. However, the results still remained dispute. Consequently, we conducted this meta-analysis to estimate the relationship between them.

METHODS

PubMed, EMBASE, and Web of Science were systematically searched for related articles to evaluate the association between "stroke" and "telomere length. STATA 12.0 software was used to perform the meta-analysis. The Cochran Q test and inconsistency index (I) were used to assess the heterogeneity. Begg funnel plot and Egger test were used to assess publication bias.

RESULTS

The meta-analysis was composed of 11 studies, consisting of 25,340 participants. We found a significant relationship between shortened telomere length and stroke (OR: 1.50, 95% CI: 1.13-2.0; P = .005); however, in the prospective and retrospective study subgroup, we did not find a statistical significant relationship between shortened telomere length and stroke (the prospective subgroup: OR: 1.41, 95% CI: 1-1.98; P = .051) (the retrospective subgroup: OR: 1.89, 95% CI: 0.96-3.72; P = .067).