Inhibition of brain damage by edaravone, a free radical scavenger, can be monitored by plasma biomarkers that detect oxidative and astrocyte damage in patients with acute cerebral infarction

Edaravone dexborneol regulates γ-aminobutyric acid transaminase in rats with acute intracerebral hemorrhage

OBJECTIVES

Edaravone dexborneol is neuroprotective against ischemic stroke, with free radical-scavenging and anti-inflammatory effects, but its effects in hemorrhagic stroke remain unclear. We evaluated whether edaravone dexborneol has a neuroprotective effect in intracerebral hemorrhage, and its underlying mechanisms.

MATERIALS AND METHODS

Bioinformatics were used to predict the pathway of action of edaravone dexborneol. An intracerebral hemorrhage model was established using type IV collagenase in edaravone dexborneol, intracerebral hemorrhage, Sham, adeno-associated virus + edaravone dexborneol, and adeno-associated virus + intracerebral hemorrhage groups. The modified Neurological Severity Score was used to evaluate neurological function in rats. Brain water content was measured using the dry-wet weight method. Tumor necrosis factor-α, interleukin-1β, inducible nitric oxide synthase, and γ-aminobutyric acid levels were determined by enzyme-linked immunosorbent assay. The expression levels of neurofilament light chain and γ-aminobutyric acid transaminase were determined by western blot. Nissl staining was used to examine neuronal morphology. Cognitive behavior was evaluated using a small-animal treadmill.

RESULTS

Edaravone dexborneol alleviated neurological defects, improved cognitive function, and reduced cerebral edema, neuronal degeneration, and necrosis in rats with cerebral hemorrhage. The expression levels of neurofilament light chain, tumor necrosis factor-α, interleukin-1β, inducible nitric oxide synthase, and γ-aminobutyric acid were decreased, while γ-aminobutyric acid transaminase expression was up-regulated.

CONCLUSIONS

Edaravone dexborneol regulates γ-aminobutyric acid content by acting on the γ-aminobutyric acid transaminase signaling pathway, thus alleviating oxidative stress, neuroinflammation, neuronal degeneration, and death caused by excitatory toxic injury of neurons after intracerebral hemorrhage.

The Specific Role of Reactive Astrocytes in Stroke

Astrocytes are essential in maintaining normal brain functions such as blood brain barrier (BBB) homeostasis and synapse formation as the most abundant cell type in the central nervous system (CNS). After the stroke, astrocytes are known as reactive astrocytes (RAs) because they are stimulated by various damage-associated molecular patterns (DAMPs) and cytokines, resulting in significant changes in their reactivity, gene expression, and functional characteristics. RAs perform multiple functions after stroke. The inflammatory response of RAs may aggravate neuro-inflammation and release toxic factors to exert neurological damage. However, RAs also reduce excitotoxicity and release neurotrophies to promote neuroprotection. Furthermore, RAs contribute to angiogenesis and axonal remodeling to promote neurological recovery. Therefore, RAs' biphasic roles and mechanisms make them an effective target for functional recovery after the stroke. In this review, we summarized the dynamic functional changes and internal molecular mechanisms of RAs, as well as their therapeutic potential and strategies, in order to comprehensively understand the role of RAs in the outcome of stroke disease and provide a new direction for the clinical treatment of stroke.

Drug Repurposing: Promises of Edaravone Target Drug in Traumatic Brain Injury

Edaravone is a potent free-radical scavenger that has been in the market for more than 30 years. It was originally developed in Japan to treat strokes and has been used there since 2001. Aside from its anti-oxidative effects, edaravone demonstrated beneficial effects on proinflammatory responses, nitric oxide production, and apoptotic cell death. Interestingly, edaravone has shown neuroprotective effects in several animal models of diseases other than stroke. In particular, edaravone administration was found to be effective in halting amyotrophic lateral sclerosis (ALS) progression during the early stages. Accordingly, after its success in Phase III clinical studies, edaravone has been approved by the FDA as a treatment for ALS patients. Considering its promises in neurological disorders and its safety in patients, edaravone is a drug of interest that can be repurposed for traumatic brain injury (TBI) treatment. Drug repurposing is a novel approach in drug development that identifies drugs for purposes other than their original indication. This review presents the biochemical properties of edaravone along with its effects on several neurological disorders in the hope that it can be adopted for treating TBI patients.

Reactive Oxygen Species Scavenger in Acute Intracerebral Hemorrhage Patients: A Multicenter, Randomized Controlled Trial

[Figure: see text].

Efficacy and safety of edaravone for acute intracerebral haemorrhage: protocol for a systematic review and meta-analysis

INTRODUCTION

Intracerebral haemorrhage (ICH) is a life-threatening condition with no effective internal treatment options. However, edaravone is a promising therapeutic agent, although its beneficial effects are inconclusive based on previous systematic reviews and meta-analyses. While several trials in the last 8 years have reported the favourable long-term functional outcomes, a few reports indicated edaravone to be associated with an increase in adverse events.

METHODS AND ANALYSIS

This protocol was performed in accordance with the Preferred Reporting Items for Systematic Review and Meta-Analysis Protocols. We will perform the comprehensive and manual search for published articles, ongoing trials, dissertations and grey literature. The following databases will be searched from inception to 23 April 2020: Medline, Embase, the Cochrane Central Register of Controlled Trials, China National Knowledge Infrastructure, Chinese scientific periodical database of VIP INFORMATION, Wanfang Data and SinoMed, with no language restrictions. All randomised controlled trials that (1) compared edaravone with placebo or no treatment, and (2) compared edaravone plus routine treatment or cointervention with routine treatment or cointervention for treating acute ICH will be included. Mortality and long-term dependency will be the primary outcomes. The incidence of adverse events will be assessed for safety evaluation. Two reviewers in pairs will independently carry out the article selection, data extraction and quality assessment. Assessment of the risk of bias and data synthesis will be performed using software Review Manager V.5.3. Finally, we will use the Grading of Recommendations Assessment, Development and Evaluation approach to evaluate the quality of the overall evidence.

ETHICS AND DISSEMINATION

There are no ethical considerations associated with this updated systematic review and meta-analysis. The findings will be disseminated in peer-reviewed journals or conference presentations.

PROSPERO REGISTRATION NUMBER

CRD42019147801.

Predicting the Pharmacokinetic Characteristics of Edaravone Intravenous Injection and Sublingual Tablet Through Modeling and Simulation

PURPOSE

Edaravone is a free-radical scavenger with relatively favorable properties of brain penetration. It has been approved for the indications of acute ischemic stroke and amyotrophic lateral sclerosis (ALS). This study aimed to establish a pharmacokinetic (PK) model to fit the PK profile of edaravone after a single sublingual (SL) dose of a novel edaravone tablet and single IV infusion of injectable edaravone in healthy Chinese volunteers participating in a bioavailability study. The model is expected to be useful for predicting the concentration-time profiles of edaravone following different dosing regimens in a healthy Chinese population. The purposes were to identify an optimal dose and dosing regimen for the new SL formulation and to support future clinical exploration of this tablet product in its approved indications and other therapeutic fields being developed.

METHODS

The PK profiles after a single SL dose or IV infusion of edaravone 30 mg can be well described by a 3-compartment linear disposition model, on which a first-order absorption model with a lag time and a parameter for bioavailability was incorporated to fit the absorption phase of the SL dose. Performance of these PK models was evaluated for goodness of fit, residual trends, visual predictive checks, as well as precision of model predictions against external data. The validated models were employed for simulating the PK profiles of edaravone after a single SL dose of 60 mg and IV infusion of 60 mg for 60 min.

FINDINGS

The resultant estimates support the possibility and feasibility of demonstrating bioequivalence between an SL administration of edaravone 60 mg and the currently approved dosing regimen for ALS (ie, 60 mg IV over 60 min) once per day. The calculation of sample size suggested that the requirement for subject number was acceptable considering the general capacity of a Phase I study center, and so were the procedures defined in the protocol.

IMPLICATION

The models can be further applied to simulate favorable concentration-time profiles in diseases with different underlying courses of oxidative stress, and hence facilitate the optimization of current dosing regimens.

The Significance of Oxidized Low-Density Lipoprotein in Body Fluids as a Marker Related to Diseased Conditions

Oxidatively modified low-density lipoprotein (oxLDL) is known to be involved in various diseases, including cardiovascular diseases. The presence of oxLDL in the human circulatory system and in atherosclerotic lesions has been demonstrated using monoclonal antibodies. Studies have shown the significance of circulating oxLDL in various systemic diseases, including acute myocardial infarction and diabetic mellitus. Several different enzyme-linked immunosorbent assay (ELISA) procedures to measure oxLDL were utilized. Evidence has been accumulating that reveals changes in oxLDL levels under certain pathological conditions. Since oxLDL concentration tends to correlate with low-density lipoprotein (LDL)-cholesterol, the ratio of ox-LDL and LDL rather than oxLDL concentration alone has also been focused. In addition to circulating plasma, LDL and oxLDL are found in gingival crevicular fluid (GCF), where the ratio of oxLDL to LDL in GCF is much higher than in plasma. LDL and oxLDL levels in GCF show an increase in diabetic patients and periodontal patients, suggesting that GCF might be useful in examining systemic conditions. GCF oxLDL increased when the teeth were affected by periodontitis. It is likely that oxLDL levels in plasma and GCF could reflect oxidative stress and transfer efficacy in the circulatory system.

Formulary Drug Review: Edaravone

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How is edaravone effective against acute ischemic stroke and amyotrophic lateral sclerosis?

Edaravone is a low-molecular-weight antioxidant drug targeting peroxyl radicals among many types of reactive oxygen species. Because of its amphiphilicity, it scavenges both lipid- and water-soluble peroxyl radicals by donating an electron to the radical. Thus, it inhibits the oxidation of lipids by scavenging chain-initiating water-soluble peroxyl radicals and chain-carrying lipid peroxyl radicals. In 2001, it was approved in Japan as a drug to treat acute-phase cerebral infarction, and then in 2015 it was approved for amyotrophic lateral sclerosis (ALS). In 2017, the U.S. Food and Drug Administration also approved edaravone for treatment of patients with ALS. Its mechanism of action was inferred to be scavenging of peroxynitrite. In this review, we focus on the radical-scavenging characteristics of edaravone in comparison with some other antioxidants that have been studied in clinical trials, and we summarize its pharmacological action and clinical efficacy in patients with acute cerebral infarction and ALS.

Protective Effect of Edaravone against Carbon Monoxide Induced Apoptosis in Rat Primary Cultured Astrocytes

Objective. To observe the protective effect of edaravone (Eda) on astrocytes after prolonged exposure to carbon monoxide (CO) and further to investigate the potential mechanisms of Eda against CO-induced apoptosis. Methods. The rat primary cultured astrocytes were cultured in vitro and exposed to 1% CO for 24 h after being cultured with different concentrations of Eda. MTT assay was used to detect the cytotoxicity of CO. Flow cytometry was used to detect the apoptosis rate, membrane potential of mitochondria, and ROS level. The mRNA and protein expressions of Bcl-2, Bax, and caspase-3 were assessed by real-time PCR and Western blotting analysis, respectively. Results. Eda can significantly suppress cytotoxicity of CO, and it can significantly increase membrane potential of mitochondria and Bcl-2 expressions and significantly suppress the apoptosis rate, ROS level, Bax, and caspase-3 expressions. Conclusion. Eda protects against CO-induced apoptosis in rat primary cultured astrocytes through decreasing ROS production and subsequently inhibiting mitochondrial apoptosis pathway.

Pathophysiology and Treatments of Oxidative Injury in Ischemic Stroke: Focus on the Phagocytic NADPH Oxidase 2

SIGNIFICANCE

Phagocytes play a key role in promoting the oxidative stress after ischemic stroke occurrence. The phagocytic NADPH oxidase (NOX) 2 is a membrane-bound enzyme complex involved in the antimicrobial respiratory burst and free radical production in these cells.

RECENT ADVANCES

Different oxidants have been shown to induce opposite effects on neuronal homeostasis after a stroke. However, several experimental models support the detrimental effects of NOX activity (especially the phagocytic isoform) on brain recovery after stroke. Therapeutic strategies selectively targeting the neurotoxic ROS and increasing neuroprotective oxidants have recently produced promising results.

CRITICAL ISSUES

NOX2 might promote carotid plaque rupture and stroke occurrence. In addition, NOX2-derived reactive oxygen species (ROS) released by resident and recruited phagocytes enhance cerebral ischemic injury, activating the inflammatory apoptotic pathways. The aim of this review is to update evidence on phagocyte-related oxidative stress, focusing on the role of NOX2 as a potential therapeutic target to reduce ROS-related cerebral injury after stroke.

FUTURE DIRECTIONS

Radical scavenger compounds (such as Ebselen and Edaravone) are under clinical investigation as a therapeutic approach against stroke. On the other hand, NOX inhibition might represent a promising strategy to prevent the stroke-related injury. Although selective NOX inhibitors are not yet available, nonselective compounds (such as apocynin and fasudil) provided encouraging results in preclinical studies. Whereas additional studies are needed to better evaluate this therapeutic potential in human beings, the development of specific NOX inhibitors (such as monoclonal antibodies, small-molecule inhibitors, or aptamers) might further improve brain recovery after stroke.

Anti-inflammatory effects of Edaravone and Scutellarin in activated microglia in experimentally induced ischemia injury in rats and in BV-2 microglia

Background

In response to cerebral ischemia, activated microglia release excessive inflammatory mediators which contribute to neuronal damage. Therefore, inhibition of microglial over-activation could be a therapeutic strategy to alleviate various microglia-mediated neuroinflammation. This study was aimed to elucidate the anti-inflammatory effects of Scutellarin and Edaravone given either singly, or in combination in activated microglia in rats subjected to middle cerebral artery occlusion (MCAO), and in lipopolysaccharide (LPS)-induced BV-2 microglia. Expression of proinflammatory cytokines, including tumor necrosis factor-alpha (TNF-α), interleukin-1 beta (IL-1β), and inducible nitric oxide synthase (iNOS) was assessed by immunofluorescence staining and Western blot. Reactive oxygen species (ROS) and nitric oxide (NO) levels were determined by flow cytometry and fluorescence microscopy, respectively.

Results

In vivo, both Edaravone and Scutellarin markedly reduced the infarct cerebral tissue area with the latter drug being more effective with the dosage used; furthermore, when used in combination the reduction was more substantial. Remarkably, a greater diminution in distribution of activated microglia was observed with the combined drug treatment which also attenuated the immunoexpression of TNF-α, IL-1β and iNOS to a greater extent as compared to the drugs given separately. In vitro, both drugs suppressed upregulated expression of inflammatory cytokines, iNOS, NO and ROS in LPS-induced BV-2 cells. Furthermore, Edaravone and Scutellarin in combination cumulatively diminished the expression levels of the inflammatory mediators being most pronounced for TNF-α as evidenced by Western blot.

Conclusion

The results suggest that Edaravone and Scutellarin effectively suppressed the inflammatory responses in activated microglia, with Scutellarin being more efficacious within the dosage range used. Moreover, when both drugs were used in combination, the infarct tissue area was reduced more extensively; also, microglia-mediated inflammatory mediators notably TNF-α expression was decreased cumulatively.

Electronic supplementary material

The online version of this article (doi:10.1186/s12868-014-0125-3) contains supplementary material, which is available to authorized users.

The radical scavenger edaravone improves neurologic function and perihematomal glucose metabolism after acute intracerebral hemorrhage

Oxidative injury caused by reactive oxygen species plays an important role in the progression of intracerebral hemorrhage (ICH)-induced secondary brain injury. Previous studies have demonstrated that the free radical scavenger edaravone may prevent neuronal injury and brain edema after ICH. However, the influence of edaravone on cerebral metabolism in the early stages after ICH and the underlying mechanism have not been fully investigated. In the present study, we investigated the effect of edaravone on perihematomal glucose metabolism using (18)F-fluorordeoxyglucose (FDG) positron emission tomography/computed tomography (PET/CT). Additionally, the neurologic deficits, brain edemas, and cell death that followed ICH were quantitatively analyzed. After blood infusion, the rats treated with edaravone showed significant improvement in both forelimb placing and corner turn tests compared with those treated with vehicle. Moreover, the brain water content of the edaravone-treated group was significantly decreased compared with that of the vehicle group on day 3 after ICH. PET/CT images of ICH rats exhibited obvious decreases in FDG standardized uptake values in perihematomal region on day 3, and the lesion-to-normal ratio of the edaravone-treated ICH rats was significantly increased compared with that of the control rats. Calculation of the brain injury volumes from the PET/CT images revealed that the volumes of the blood-induced injuries were significantly smaller in the edaravone group compared with the vehicle group. Terminal Deoxynucleotidyl Transferase-mediated dUTP Nick End Labeling assays performed 3 days after ICH revealed that the numbers of apoptotic cells in perihematomal region of edaravone-treated ICH rats were decreased relative to the vehicle group. Thus, the present study demonstrates that edaravone has scavenging properties that attenuate neurologic behavioral deficits and brain edema in the early period of ICH. Additionally, edaravone may improve cerebral metabolism around the hematoma by attenuating apoptotic cell death after ICH.

Simultaneous administration of recombinant tissue plasminogen activator and edaravone in acute cerebral ischemic stroke patients

Among the 1052 patients admitted to our hospital because of cerebral infarction between January 1, 2007, and December 31, 2010, we report the treatment outcomes of 48 patients (4.6% of all patients) who received recombinant tissue plasminogen activator (rt-PA) therapy (simultaneously combined with edaravone) within 3 hours after the onset of infarction. Twenty (41.7%) patients started receiving edaravone before rt-PA administration, and 28 patients (58.3%) started receiving rt-PA and edaravone simultaneously. The patients had an average age of 73.5 years (range, 55-93 years; male:female, 32:16). Medical histories included hypertension, diabetes mellitus, dyslipidemia, arterial fibrillation, and a smoking history in 23 (47.8%), 7 (14.6%), 8 (16.7%), 29 (60.4%), and 8 (16.7%) of patients, respectively. Regarding the treatment outcome of the therapy, the National Institutes of Health Stroke Scale score, which was 15 points before rt-PA administration, showed a statistically significant improvement to 8 points after rt-PA administration (P < .001). The modified Rankin Scale scores at 90 days after treatment were as follows: 0 in 12 patients (25.0%), 1 in 11 patients (22.9%), 2 in 7 patients (14.6%), 3 in 5 patients (10.4%), 4 in 6 patients (12.5%), 5 in 5 patients (10.4%), and 6 in 2 patients (4.2%). The occluded blood vessel reopened completely in 30 patients (62.5%) and partially in 5 patients (10.4%). Asymptomatic hemorrhage over the entire brain developed in 2 patients (4.2%). Thus, rt-PA therapy in combination with edaravone improved the recanalization rate, reduced the incidence of intracranial hemorrhage, and improved functional prognosis.

The treatment of Alzheimer's disease using Chinese medicinal plants: from disease models to potential clinical applications

ETHNOPHARMACOLOGICAL RELEVANCE

Alzheimer's disease (AD) is characterized by the sustained higher nervous disorders of the activities and functions of the brain. Due to its heavy burden on society and the patients' families, it is urgent to review the treatments for AD to provide basic data for further research and new drug development. Among these treatments, Chinese Material Medica (CMM) has been traditionally clinical used in China to treat AD for a long time with obvious efficacy. With the further research reports of CMM, new therapeutic materials may be recovered from troves of CMM. However, So far, little or no review work has been reported to conclude anti-AD drugs from CMM in literature. Therefore, a systematic introduction of CMM anti-AD research progress is of great importance and necessity. This paper strives to systematically describe the progress of CMM in the treatment of AD, and lays a basis data for anti-AD drug development from CMM, and provides the essential theoretical support for the further development and utilization of CMM resources through a more comprehensive research of the variety of databases regarding CMM anti-AD effects reports.

MATERIAL AND METHODS

Literature survey was performed via electronic search (SciFinder®, Pubmed®, Google Scholar and Web of Science) on papers and patents and by systematic research in ethnopharmacological literature at various university libraries.

RESULTS

This review mainly introduces the current research on the Chinese Material Medica (CMM) theoretical research on Alzheimer's disease (AD), anti-AD active constituent of CMM, anti-AD effects on AD models, anti-AD mechanism of CMM, and anti-AD effect of CMM formula.

CONCLUSION

Scholars around the world have made studies on the anti-AD molecular mechanism of CMM from different pathways, and have made substantial progress. The progress not only enriched the anti-AD theory of CMM, but also provided clinical practical significance and development prospects in using CMM to treat AD. Western pure drugs cannot replace the advantages of CMM in the anti-AD aspect. Therefore, in the near future, the development of CMM anti-AD drugs with a more clearly role and practical data will be a major trend in the field of AD drug development, and it will promote the use of CMM.

Safety of intravenous administration of hydrogen-enriched fluid in patients with acute cerebral ischemia: initial clinical studies

BACKGROUND

Most of the results regarding hydrogen (H2) therapy for acute cerebral ischemia are derived from in vitro studies and animal experiments, with only a few obtained from human trials with a limited number of subjects. Thus, there is a paucity of information regarding both the beneficial therapeutic effects as well as the side effects of H2 on acute cerebral ischemia in humans. We designed a pilot study to investigate single dose intravenous H2-administration in combination with edaravone, aiming to provide an initial estimate of the possible risks and benefits in select patients presenting with acute ischemic stroke.

METHODS

An open-label, prospective, non-randomized study of intravenous H2-administration was performed in 38 patients hospitalized for acute ischemic stroke. All patients received an H2-enriched intravenous solution in addition to edaravone immediately after the diagnosis of acute ischemic stroke. Acute stroke patients within 3 h of onset received intravenous tissue plasminogen activator (t-PA) (0.6 mg/kg) treatment, and patients receiving t-PA had to commence the administration of the H2-enriched intravenous solution and edaravone before or at the same time as the t-PA was infused.

RESULTS

Complications were observed in 2 patients (5.3%), which consisted of diarrhea in 1 patient (2.6%) and cardiac failure in 1 patient (2.6%). No deterioration in laboratory tests, urinary tests, ECG, or chest X-ray radiograms occurred in any patient in this study. In all patients, the mean National Institutes of Health Stroke Scale (NIHSS) scores at baseline, and 7, 30, and 90 d after admission were 8.2 ± 7.5, 5.6 ± 7.1, 4.9 ± 6.5, and 4.5 ± 6.3, respectively. The early recanalization was identified in 4 of 11 patients (36.4%) who received intravenous t-PA administration. Hemorrhagic transformation was observed in 2 patients (18.2%). None of the patients in this study that were treated with t-PA developed symptomatic intracranial hemorrhage.

CONCLUSIONS

Data from the current study indicate that an H2-enriched intravenous solution is safe for patients with acute cerebral infarction, including patients treated with t-PA.

Aminophylline, administered at usual doses for rodents in pharmacological studies, induces hippocampal neuronal cell injury under low tidal volume hypoxic conditions in guinea-pigs

OBJECTIVES

To establish whether aminophylline, administered at usual doses for rodents in pharmacological studies, induces brain injury in systemic hypoxaemia in guinea-pigs.

METHODS

 A hypoxaemia (partial oxygen tension of arterial blood (PaO₂) = 40-60 mmHg) model was developed by low tidal volume mechanical ventilation in guinea-pigs.

KEY FINDINGS

Under hypoxic conditions, aminophylline significantly increased the concentration of brain-specific creatine kinase in the serum in a dose- and time-dependent manner. A reduced number of hippocampal neuronal cells in the CA1 region, an increase in the concentration of neuron-specific enolase (NSE) in cerebrospinal fluid (CSF), an increase in lipid hydroperoxides and a decrease in the ratio of glutathione to glutathione disulfide in the brain tissues were also observed. These effects were not observed when aminophylline at the same doses was administered under normoxic conditions (PaO₂ = 80-100 mmHg). There was no difference in either serum or CSF concentrations of theophylline between normoxic and hypoxic conditions. Another methylxanthine, caffeine, did not increase the concentration of NSE in CSF.

CONCLUSIONS

Aminophylline potentially induces brain damage under hypoxic conditions. We suggest that aminophylline treatment has adverse effects in patients with hypoxaemia subsequent to respiratory disorders such as asthma.

The Relation of Urinary 8-OHdG, A Marker of Oxidative Stress to DNA, and Clinical Outcomes for Ischemic Stroke

Background:

Oxidative stress/free radical generation after ischemic stroke contributes to neuronal cell injury. We evaluated the utility of an oxidative stress marker, urinary 8-hydroxy-2-deoxyguanosine (8-OHdG), to demonstrate an association between the changes of 8-OHdG and outcomes after acute ischemic stroke.

Methods:

We enrolled 44 patients (26 males and 18 females) who visited our hospital due to acute ischemic stroke. Urine was collected on admission and on Days 7, and 8-OHdG was measured by ELISA. The relationships between 8-OHdG levels, stroke subtypes, and clinical outcomes based on the NIHSS and modified Rankin Scale (mRS) upon discharge was evaluated.

Results:

In the overall cohort, the mean urinary level of 8-OHdG on Day 7 was increased than that on Day 0. The 8-OHdG levels on Day 0 were not different between patients with poor and good outcomes. However, an increasing rate from Day 0 to 7 (Δ 8-OHdG) in stroke patients with a poor outcome(mRS ≥3) was significantly higher than those with a good outcome (mRS ≤2) (2.54 vs 39.44, p = 0.004).

Conclusions:

The biochemical changes related to 8-OHdG and oxidative stress may be considered a marker of ischemic brain injury and clinical outcome of ischemic stroke.

TAT-NEP1-40 as a novel therapeutic candidate for axonal regeneration and functional recovery after stroke

Currently available therapeutics has been less effective in promoting functional recovery from stroke or other injuries in the central nervous system (CNS). Axonal damage is a characteristic pathology seen in CNS injuries. Previously, it was reported that Nogo-A extracellular peptide residues 1-40 (NEP1-40), a competitive antagonist of Nogo-66 receptor (NgR1), has the ability to promote axonal regrowth and functional recovery after CNS injury. However, delivery of the therapeutic proteins into the brain parenchyma is limited due to its inability to cross the blood-brain barrier (BBB). We first generated a biologically active NEP1-40 fusion protein containing the protein transduction domain (PTD) of the transactivator of transcription (TAT), TAT-NEP1-40, which crosses the BBB in vivo after systemic delivery. The TAT-NEP1-40 can protect PC12 cells against oxygen and glucose deprivation (OGD) and promote neurite outgrowth when added exogenously to culture medium. The TAT-NEP1-40 protein transduced into the brain continued to sustain biological activities and protected the brain against ischemia/reperfusion injury through inhibition of neuronal apoptosis. Collectively, our data suggest that TAT-NEP1-40 may be a novel therapeutic candidate for axonal regeneration and functional recovery from CNS injuries such as cerebral hypoxia-ischemia, cerebral hemorrhage, brain trauma, and also for spinal cord injury.

Small temperature variations alter edaravone-induced neuroprotection of cortical cultures exposed to prolonged hypoxic episodes

BACKGROUND

Edaravone, a free radical scavenger, has been shown to be neuroprotective in vivo and in vitro. However, the impact of small temperature variations on its neuroprotective actions remains unknown.

METHODS

We examined the degree of neuroprotection conferred by various concentrations of edaravone on cortical cultures exposed to prolonged hypoxia (24 h) under three conditions: mild hypothermia (32 degrees C), normothermia (37 degrees C), and mild hyperthermia (39 degrees C). The survival of cortical neurones from E16 Wistar rats (SR) was evaluated using photomicrographs taken before and after exposure to hypoxia.

RESULTS

The mean survival of neurones exposed to hypoxia at normothermia was 14.7 (sem 1.8)%. The addition of 50 microM edaravone significantly improved the mean survival to 40.5 (4.7)%. This improvement was noted at higher doses of edaravone (5 microM < or =) but not at lower doses (< or =500 nM). With mild hypothermia and prolonged hypoxia without edaravone, neuroprotection was significantly improved with a mean survival of 63.0 (5.2)%. This neuroprotective effect was not enhanced with the addition of edaravone, even at the highest dose. Hypoxia-induced neurotoxicity was aggravated by mild hyperthermia as reflected by a mean survival of 9.1 (2.1)%. However, higher concentrations of edaravone inhibited the deleterious effect of mild hyperthermia, thereby demonstrating a significant neuroprotective effect. The survival of neurones subjected to both hyperthermia and edaravone was the same as that of neurones exposed to normothermia and edaravone.

CONCLUSIONS

Temperature is a potential factor in determining whether edaravone confers a neuroprotective effect when applied during prolonged hypoxic insults.

Biomarkers of oxidative stress in heart failure

Oxidative stress is the relative excess of reactive oxygen species (ROS) versus endogenous defense mechanisms. Abundant evidence has demonstrated the role of ROS, along with reactive nitrogen species (RNS), in the pathophysiology of cardiovascular disease, including heart failure. Many biomarkers of oxidative stress have been studied as surrogates of oxidative damage. Recently, markers of impaired nitric oxide signaling have also been identified. Many biomarkers have been associated with prognosis and mortality, and some may even be modified by therapy. However, the clinical utility is limited by less than optimal standardization techniques and the lack of sufficient large-sized, multimarker prospective trials.

Acute phase proteins and oxidised low-density lipoprotein in association with ischemic stroke subtype, severity and outcome

OBJECTIVES

The goal of our study was to investigate the associations of oxidized LDL (apoB100 aldehyde-modified form) and acute phase proteins (fibrinogen, CRP) with acute ischemic stroke severity and outcome.

MATERIALS AND METHODS

The study included 61 ischemic stroke patients and 64 controls. Strokes were subtyped according to TOAST criteria, the severity and outcome of stroke (at 1 year) were measured.

RESULTS

The mean triglyceride, fibrinogen, CRP and glucose values were significantly higher among cases. The median oxLDL value for patients with large artery atherosclerosis (LAA) type of stroke was significantly higher than for other subtypes. The oxLDL values did not correlate with age, stroke severity and outcome.

CONCLUSIONS

Inflammatory markers (fibrinogen and CRP) predicted the stroke severity and outcome whereas elevation of oxLDL levels did not. Our data refer to possibility that there may exist some links between the LAA subtype of stroke and elevated oxLDL (apoB100 aldehyde-modified form).

Edaravone inhibits DNA peroxidation and neuronal cell death in neonatal hypoxic-ischemic encephalopathy model rat

Neonatal hypoxic-ischemic encephalopathy (HIE) is the most frequent neurologic disease in the perinatal period. Its major cause is oxidative stress, which induces DNA peroxidation and apoptotic neuronal death. We examined 8-hydroxy-2'-deoxyguanosine (8-OHdG) expression to evaluate brain damage in neonatal HIE and the therapeutic effect of edaravone, a free radical scavenger. Using HPLC and immunohistochemistry, the 8-OHdG levels of neonatal HIE model Sprague-Dawley rats that were subjected to left common carotid artery ligation and 2-h hypoxia significantly increased after 24-48 h of hypoxic-ischemic (HI) insult, but decreased after 72 h. Moreover, the number of apoptotic cells with terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling and karyorrhexis significantly increased after 24-72 h of HI insult. In a therapeutic experiment, edaravone was administered i.p. (9 mg/kg) after HI insult every 24 h. Edaravone reduced both the apoptotic neuronal cell number and 8-OHdG expression after 24-48 h of HI. From a double immunofluorescent study, DNA peroxidation occurred in apoptotic neuronal cells with 8-OHdG expression. Edaravone may inhibit the number of apoptotic neuronal cells and 8-OHdG expression within 48 h after HI insult.

Edaravone for the treatment of acute cerebral infarction: role of endothelium-derived nitric oxide and oxidative stress

Thrombolytic therapy is the most effective therapeutic strategy for the prevention of brain injury and reduction of mortality in patients with acute cerebral infarction. A combination of established thrombolytic therapy and effective neuronal protection therapy has more beneficial effects for patients with acute cerebral infarction. Edaravone (chemical name: 3-methyl-1-phenyl-2-pyrazolin-5-one) is a strong, novel scavenger of free radicals. Several lines of evidence have shown that edaravone has preventive effects on brain injury following ischaemia and reperfusion in patients with brain attack. This review focuses on putative mechanisms underlying the beneficial effects of edaravone on the atherosclerotic process in patients with stroke and on the possibility of edaravone-induced extension of the therapeutic time window in patients with acute cerebral infarction.

Protective effects of free radical scavenger edaravone against xanthine oxidase-mediated permeability increases in human intestinal epithelial cell monolayer

The barrier function of the intestinal mucosa can be disturbed under a variety of pathologic insults. Reactive oxygen species play an important role in intestinal mucosal injury. This in vitro study examines the hypothesis that a free radical scavenger, edaravone (ED), ameliorates gut epithelial permeability increase caused by xanthine oxidase (XO)-mediated oxidative stress in a cell monolayer model. Human intestinal epithelial (HIE) cells were grown as monolayer in bicameral chambers. Twenty milliunits per milliliter of XO+0.25 mM of xanthine (XO+X group) or saline (control) were administered into the basal chambers. Another set of chambers was treated with XO+X and 0.6 mg/ml of ED (XO+X+ED group). The permeability was assessed by quantifying the transepithelial passage of fluorescence in isothiocyanate-labeled dextran. In another series of experiments, Escherichia coli C-25 was also applied in an apical chamber to evaluate the bacterial translocation through the monolayer. The concentration of the fluorescence in isothiocyanate-labeled dextran in the basal chamber of the control group was significantly higher than the control (705 +/- 50.2 vs 155 +/- 45.4 mg/dl, P < .01). Treatment with ED prevented this permeability increase induced by the oxidative stress (P < .01). The incidence of bacterial translocation through the HIE monolayer in XO+X group was also higher than that of the control group (75 vs 13%, P < .05). Increased HIE cell monolayer permeability mediated by xanthine and XO was significantly attenuated with ED. This synthesized radical scavenger may have potential clinical applications against gut mucosal barrier dysfunction.

The novel antioxidant edaravone: from bench to bedside

Over the last decade, important advances have been made to support the fact that reactive oxygen species (ROS) are generated and play a harmful role during the acute and late stages of cerebral ischemia. Several drugs, such as radical scavengers and antioxidants, have been evaluated in preclinical and clinical studies. Edaravone (3-methyl-1-phenyl-2-pyrazolin-5-one; Radicut, Mitsubishi Tanabe Pharma Corporation) is a novel antioxidant that is currently used in Japan for the treatment of patients in the acute stage of cerebral infarction. Edaravone scavenges ROS and inhibits proinflammatory responses after brain ischemia in animals and humans. In particular, postischemic inflammation, leading to brain edema and infarction due to neuronal damage and endothelial cell death, can be ameliorated by edaravone. In addition to these antistroke effects, edaravone has also been shown to prevent oxidative damage to various extracerebral organs. Therefore, in addition to its usefulness in the treatment of stroke, edaravone is expected to play an integral role in the treatment of many oxidative stress-related diseases.

Preoperative cerebral hemodynamic impairment and reactive oxygen species produced during carotid endarterectomy correlate with development of postoperative cerebral hyperperfusion

BACKGROUND AND PURPOSE

The purpose of the present study was to determine whether preoperative cerebral hemodynamic impairment and reactive oxygen species produced during carotid endarterectomy (CEA) correlate with development of postoperative cerebral hyperperfusion.

METHODS

Concentrations of malondialdehyde-modified low-density lipoprotein (MDA-LDL), a biochemical marker of oxidative damage, were measured in serum samples obtained from 90 patients undergoing CEA for ipsilateral ICA stenosis (>70%). Serum samples were obtained from a venous catheter inserted into the ipsilateral jugular bulb before clamping of the internal carotid artery (ICA), 10 minutes after clamping of the ICA, and 5 and 20 minutes after declamping of the ICA. Cerebral blood flow (CBF) and cerebrovascular reactivity (CVR) to acetazolamide were also measured using single-photon emission computed-tomography before CEA. In addition, CBF was measured postoperatively.

RESULTS

Hyperperfusion (CBF increase >100% compared with preoperative values) was observed immediately after CEA in 12 patients (13%). Logistic regression analysis demonstrated that reduced preoperative CVR (95% CIs, 1.053 to 1.453; P=0.0097) and an increase in MDA-LDL (calculated as a percentage of the preclamp values) after ICA declamping (95% CIs, 0.862 to 0.980; P=0.0098) were significantly associated with development of postoperative cerebral hyperperfusion among the variables tested. Ten of 11 patients with reduced preoperative CVR and increased MDA-LDL after ICA declamping developed post-CEA hyperperfusion, and 2 of these patients developed cerebral hyperperfusion syndrome.

CONCLUSIONS

Both preoperative cerebral hemodynamic impairment and reactive oxygen species produced during surgery correlate with development of cerebral hyperperfusion after CEA.

Edaravone inhibits the expression of vascular endothelial growth factor in human astrocytes exposed to hypoxia

Edaravone (3-methyl-1-phenyl-2-pyrazolin-5-one), a free radical scavenger, reduces brain edema in patients with acute ischemic stroke. We have addressed the effect of edaravone on the expression of vascular endothelial growth factor (VEGF), a potential mediator of brain edema, in astrocytes exposed to hypoxia. Normal human astrocytes in culture were treated with edaravone, and the levels of VEGF mRNA and protein were analyzed by reverse transcription-polymerase chain reaction (RT-PCR), real-time quantitative PCR and enzyme-linked immunosorbent assay (ELISA). The expression of hypoxia-inducible factor-1alpha (HIF-1alpha), a transcriptional activator of VEGF, was examined by RT-PCR, real-time PCR and western blotting; and the binding of HIF-1alpha to the promoter region of VEGF gene by chromatin immunoprecipitation (ChIP) assay. Edaravone moderately suppressed the expression of VEGF mRNA and protein in astrocytes under hypoxia in time- and concentration-dependent manners. It also suppressed the accumulation of HIF-1alpha in the nuclei under hypoxia. ChIP assay confirmed that edaravone reduced HIF-1alpha binding to VEGF promoter. We conclude that edaravone inhibits VEGF expression in astrocytes exposed to hypoxia, at least partly, through the down-regulation of HIF-1alpha. These findings offer a partial explanation for the protective effect of edaravone on the development of brain edema in patients with acute ischemic stroke.

CONCENTRATION OF MALONDIALDEHYDE-MODIFIED LOW-DENSITY LIPOPROTEIN IN THE JUGULAR BULB DURING CAROTID ENDARTERECTOMY CORRELATES WITH DEVELOPMENT OF POSTOPERATIVE COGNITIVE IMPAIRMENT

OBJECTIVE

Approximately 20 to 30% of patients undergoing carotid endarterectomy (CEA) subsequently develop cognitive impairment. The purpose of the present study is to determine whether or not malondialdehyde (MDA)-modified low-density lipoprotein (LDL), a biochemical marker of oxidative damage, concentrations in the jugular bulb during CEA correlates with development of postoperative cognitive impairment.

METHODS

Fifty-five patients undergoing CEA were assessed with a battery of neuropsychological tests before and 1 month after surgery. Serum samples for measurement of MDA-LDL concentration were obtained from a venous catheter inserted into the ipsilateral jugular bulb at the following time points: immediately before clamping of the internal carotid artery (ICA), 10 minutes after clamping of the ICA, and 5 and 20 minutes after declamping of the ICA.

RESULTS

The MDA-LDL concentrations at 5 and 20 minutes after ICA declamping were both significantly higher than concentrations before ICA clamping (P < 0.0001). At the postoperative neuropsychological assessment, six (11%) out of 55 patients showed postoperative cognitive impairment. Logistic regression analysis demonstrated that higher values of MDA-LDL increase (calculated as a percentage of the preclamp values) at either 5 or 20 minutes after ICA declamping were significantly associated with the development of postoperative cognitive impairment (95% confidence interval, 0.787-0.981; P = 0.0209) among the variables tested.

CONCLUSION

MDA-LDL concentration in the jugular bulb during CEA correlates with development of postoperative cognitive impairment.

Measurement of plasma oxidized low-density lipoprotein and its clinical implications

Oxidized low-density lipoprotein (OxLDL) has been shown to exist in human circulating plasma. Several groups including ours have developed methods for immunologically measuring OxLDL, which have been applied to several clinical, both cross-sectional and prospective, studies. These data clearly show that OxLDL levels correlate well with the severity of cardiovascular diseases. In particular, recent observations suggest that plasma OxLDL levels could be a useful marker for predicting future cardiovascular events; however, substantial differences exist among the different methods of OxLDL measurement. To evaluate the clinical data on circulating OxLDL, a proper understanding of the similarity, differences, and limitation of the methods is needed. This paper summarizes the characteristics of the methods used and recent clinical findings.

Neuroprotective actions of a histidine analogue in models of ischemic stroke

Histidine is a naturally occurring amino acid with antioxidant properties, which is present in low amounts in tissues throughout the body. We recently synthesized and characterized histidine analogues related to the natural dipeptide carnosine, which selectively scavenge the toxic lipid peroxidation product 4-hydroxynonenal (HNE). We now report that the histidine analogue histidyl hydrazide is effective in reducing brain damage and improving functional outcome in a mouse model of focal ischemic stroke when administered intravenously at a dose of 20 mg/kg, either 30 min before or 60 min and 3 h after the onset of middle cerebral artery occlusion. The histidine analogue also protected cultured rat primary neurons against death induced by HNE, chemical hypoxia, glucose deprivation, and combined oxygen and glucose deprivation. The histidine analogue prevented neuronal apoptosis as indicated by decreased production of cleaved caspase-3 protein. These findings suggest a therapeutic potential for HNE-scavenging histidine analogues in the treatment of stroke and related neurodegenerative conditions.