Edaravone, a novel radical scavenger, inhibits oxidative modification of low-density lipoprotein (LDL) and reverses oxidized LDL-mediated reduction in the expression of endothelial nitric oxide synthase

Multi-pathway neuroprotective effects of a novel salidroside derivative SHPL-49 against acute cerebral ischemic injury

SHPL-49 ((2R,3S,4S,5R,6R)-2-(hydroxymethyl)-6-(4-(4-methoxyphenyl) butoxy) tetrahydro-2H-pyran-3,4,5-triol) is a novel glycoside derivative obtained from structural modification of salidroside, which is isolated from the medicinal plant Rhodiola rosea L. SHPL-49 was administered to rats with permanent middle cerebral artery occlusion (pMCAO) for 5 days, and it was found that SHPL-49 could alleviate the cerebral infarct volume and reduce the neurological deficit score. Moreover, the effective time window of SHPL-49 in the pMCAO model was from 0.5 to 8 h after embolization. In addition, the result of immunohistochemistry showed that SHPL-49 could increase the number of neurons in the brain tissue and reduce the occurrence of apoptosis. Morris water maze and Rota-rod experiments showed that SHPL-49 could improve neurological deficits, repair neurocognitive and motor dysfunction, and enhance learning and memory ability in the pMCAO model after 14 days of SHPL-49 treatment. Further in vitro experiments showed that SHPL-49 significantly reduced the calcium overload of PC-12 cells and the production of reactive oxygen species (ROS) induced by oxygen and glucose deprivation (OGD), and increased the levels of antioxidant enzymes superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px), decreased the production of malondialdehyde (MDA). Furthermore, SHPL-49 could reduce cell apoptosis by increasing protein expression ratio of anti-apoptotic factor Bcl-2 to pro-apoptotic factor Bax in vitro. SHPL-49 also regulated the expression of Bcl-2 and Bax in ischemic brain tissue, and even inhibited the caspase cascade of pro-apoptotic proteins Cleaved-caspase 9 and Cleaved-caspase 3. Taken together, SHPL-49 exhibited neuroprotective effects against cerebral ischemic injury through multiple pathways, such as alleviating calcium overload, reducing oxidative stress damage, and inhibiting apoptosis.

The electrocardiographic, hemodynamic, echocardiographic, and biochemical evaluation of treatment with edaravone on acute cardiac toxicity of aluminum phosphide

Aluminum phosphide (AlP) poisoning can be highly fatal due to its severe toxicity to the heart. Based on the evidence, edaravone (EDA) has protective effects on various pathological conditions of the heart. This research aimed to examine the potential protective effects of EDA on AlP-induced cardiotoxicity in rats. The rats were divided into six groups, including almond oil (control), normal saline, AlP (LD₅₀), and AlP + EDA (20, 30, and 45 mg/kg). Thirty minutes following AlP poisoning, the electrocardiographic (ECG), blood pressure (BP), and heart rate (HR) parameters were examined for 180 min. The EDA was injected 60 min following the AlP poisoning intraperitoneally. Also, 24 h after poisoning, echocardiography was carried out to evaluate the ejection fraction (EF), stroke volume (SV), and cardiac output (CO). The biochemical and molecular parameters, such as the activities of the mitochondrial complexes, reactive oxygen species (ROS), apoptosis and necrosis, and troponin I and lactate levels, were also examined after 12 and 24 h in the heart tissue. According to the results, AlP-induced ECG abnormalities, decrease in blood pressure, heart rate, SV, EF%, and CO were significantly improved with EDA at doses of 30 and 45 mg/kg. Likewise, EDA significantly improved complex I and IV activity, apoptosis and necrosis, ROS, troponin I, and lactate levels following AlP-poisoning (p < 0.05). Also, the mean survival time was increased following EDA treatment, which can be attributed to the EDA’s protective effects against diverse underlying mechanisms of phosphine-induced cardiac toxicity. These findings suggest that EDA, by ameliorating heart function and modulating mitochondrial activity, might relieve AlP-induced cardiotoxicity. Nonetheless, additional investigations are required to examine any potential clinical advantages of EDA in this toxicity.

Neuroprotective approach in acute ischemic stroke: A systematic review of clinical and experimental studies

Ischemic stroke is a disease with worldwide economic and social negative effects. It is a serious disease with high disability and mortality. Ionic imbalance, excitotoxicity, oxidative stress, and inflammation are induced during and after ischemic stroke. Cellular dysfunction, apoptosis, and necrosis are activated directly or indirectly mechanisms. The studies about neuroprotection in neurodegenerative diseases have increased in recent years. Data about the mechanisms of progressive molecular improvement in the brain tissue are increasing in acute ischemic stroke. Based on these data, preclinical and clinical studies on new neuroprotective treatments are being designed. An effective neuroprotective strategy can prolong the indication period of recanalization treatments in the acute stage of ischemic stroke. In addition, it can reduce neuronal necrosis and protect the brain against ischemia-related reperfusion injury. The current review has evaluated the recent clinical and experimental studies. The molecular mechanism of each of the neuroprotective strategies is also summarized. This review may help develop future strategies for combination treatment to protect the cerebral tissue from ischemia-reperfusion injury.

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.

Mechanisms of neuronal cell death in ischemic stroke and their therapeutic implications

Ischemic stroke caused by arterial occlusion is the most common type of stroke, which is among the most frequent causes of disability and death worldwide. Current treatment approaches involve achieving rapid reperfusion either pharmacologically or surgically, both of which are time-sensitive; moreover, blood flow recanalization often causes ischemia/reperfusion injury. However, even though neuroprotective intervention is urgently needed in the event of stroke, the exact mechanisms of neuronal death during ischemic stroke are still unclear, and consequently, the capacity for drug development has remained limited. Multiple cell death pathways are implicated in the pathogenesis of ischemic stroke. Here, we have reviewed these potential neuronal death pathways, including intrinsic and extrinsic apoptosis, necroptosis, autophagy, ferroptosis, parthanatos, phagoptosis, and pyroptosis. We have also reviewed the latest results of pharmacological studies on ischemic stroke and summarized emerging drug targets with a focus on clinical trials. These observations may help to further understand the pathological events in ischemic stroke and bridge the gap between basic and translational research to reveal novel neuroprotective interventions.

Molecular and Cellular Mechanisms of Electronegative Lipoproteins in Cardiovascular Diseases

Dysregulation of glucose and lipid metabolism increases plasma levels of lipoproteins and triglycerides, resulting in vascular endothelial damage. Remarkably, the oxidation of lipid and lipoprotein particles generates electronegative lipoproteins that mediate cellular deterioration of atherosclerosis. In this review, we examined the core of atherosclerotic plaque, which is enriched by byproducts of lipid metabolism and lipoproteins, such as oxidized low-density lipoproteins (oxLDL) and electronegative subfraction of LDL (LDL(−)). We also summarized the chemical properties, receptors, and molecular mechanisms of LDL(−). In combination with other well-known markers of inflammation, namely metabolic diseases, we concluded that LDL(−) can be used as a novel prognostic tool for these lipid disorders. In addition, through understanding the underlying pathophysiological molecular routes for endothelial dysfunction and inflammation, we may reassess current therapeutics and might gain a new direction to treat atherosclerotic cardiovascular diseases, mainly targeting LDL(−) clearance.

Emerging neuroprotective strategies for the treatment of ischemic stroke: An overview of clinical and preclinical studies

Stroke is the leading cause of disability and thesecond leading cause of death worldwide. With the global population aged 65 and over growing faster than all other age groups, the incidence of stroke is also increasing. In addition, there is a shift in the overall stroke burden towards younger age groups, particularly in low and middle-income countries. Stroke in most cases is caused due to an abrupt blockage of an artery (ischemic stroke), but in some instances stroke may be caused due to bleeding into brain tissue when a blood vessel ruptures (hemorrhagic stroke). Although treatment options for stroke are still limited, with the advancement in recanalization therapy using both pharmacological and mechanical thrombolysis some progress has been made in helping patients recover from ischemic stroke. However, there is still a substantial need for the development of therapeutic agents for neuroprotection in acute ischemic stroke to protect the brain from damage prior to and during recanalization, extend the therapeutic time window for intervention and further improve functional outcome. The current review has assessed the past challenges in developing neuroprotective strategies, evaluated the recent advances in clinical trials, discussed the recent initiative by the National Institute of Neurological Disorders and Stroke in USA for the search of novel neuroprotectants (Stroke Preclinical Assessment Network, SPAN) and identified emerging neuroprotectants being currently evaluated in preclinical studies. The underlying molecular mechanism of each of the neuroprotective strategies have also been summarized, which could assist in the development of future strategies for combinational therapy in stroke treatment.

Effects of Edaravone on Nitric Oxide, Hydroxyl Radicals and Neuronal Nitric Oxide Synthase During Cerebral Ischemia and Reperfusion in Mice

BACKGROUND

The purpose of this study was to investigate the effects of edaravone on nitric oxide (NO) production, hydroxyl radical (OH^-) metabolism, and neuronal nitric oxide synthase (nNOS) expression during cerebral ischemia and reperfusion.

METHODS

Edaravone (3 mg/kg) was administered intravenously to 14 C57BL/6 mice just before reperfusion. Eleven additional mice received saline (controls). NO production and OH^- metabolism were continuously monitored using bilateral striatal in vivo microdialysis. OH^- formation was monitored using the salicylate trapping method. Forebrain ischemia was produced in all mice by bilateral occlusion of the common carotid artery for 10 minutes. Levels of NO metabolites, nitrite (NO₂^-) and nitrate (NO₃^-), were determined using the Griess reaction. Brain sections were immunostained with an anti-nNOS antibody and the fractional area density of nNOS-immunoreactive pixels to total pixels determined.

RESULTS

Blood pressure and regional cerebral blood flow were not significantly different between the edaravone and control groups. The levels of NO₂^- did not differ significantly between the 2 groups. The level of NO₃^- was significantly higher in the edaravone group compared with the control group after reperfusion. 2,3-dihydroxybenzoic acid levels were lower in the edaravone group compared with those in the control group after reperfusion. Immunohistochemistry showed nNOS expression in the edaravone group to be significantly lower than that in the control group 96 hours after reperfusion.

CONCLUSIONS

These in vivo data indicate that edaravone may have a neuroprotective effect by reducing levels of OH^- metabolites, increasing NO production and decreasing nNOS expression in brain cells.

Direct free radical scavenging effects of water-soluble HMG-CoA reductase inhibitors

3-Hydroxy-3-methylglutaryl coenzyme A reductase inhibitors, statins, are widely used for preventing cardiovascular and cerebrovascular diseases by controlling blood cholesterol level. Additionally, previous studies revealed the scavenging effects of statins on free radicals. We assessed direct scavenging activities of two water-soluble statins, fluvastatin and pravastatin, on multiple free radicals using electron spin resonance spectrometry with spin trapping method. We estimated reaction rate constants (k_fv for fluvastatin, and k_pv for pravastatin). Superoxide anion was scavenged by fluvastatin and pravastatin with k_fv and k_pv of 4.82 M⁻¹s⁻¹ and 49.0 M⁻¹s⁻¹, respectively. Scavenging effects of fluvastatin and pravastatin on hydroxyl radical were comparable; both k_fv and k_pv were >10⁹ M⁻¹s⁻¹. Fluvastatin also eliminated tert-butyl peroxyl radical with relative k_fv of 2.63 to that of CYPMPO, whereas pravastatin did not affect tert-butyl peroxyl radical. Nitric oxide was scavenged by fluvastatin and pravastatin with k_fv and k_pv of 68.6 M⁻¹s⁻¹ and 701 M⁻¹s⁻¹, respectively. Both fluvastatin and pravastatin had scavenging effects on superoxide anion, hydroxyl radical and nitric oxide radical. On the other hand, tert-butyl peroxyl radical was scavenged only by fluvastatin, suggesting that fluvastatin might have more potential effect than pravastatin to prevent atherosclerosis and ischemia/reperfusion injury via inhibiting oxidation of lipids.

A staged screening of registered drugs highlights remyelinating drug candidates for clinical trials

There is no treatment for the myelin loss in multiple sclerosis, ultimately resulting in the axonal degeneration that leads to the progressive phase of the disease. We established a multi-tiered platform for the sequential screening of drugs that could be repurposed as remyelinating agents. We screened a library of 2,000 compounds (mainly Food and Drug Administration (FDA)-approved compounds and natural products) for cellular metabolic activity on mouse oligodendrocyte precursors (OPC), identifying 42 molecules with significant stimulating effects. We then characterized the effects of these compounds on OPC proliferation and differentiation in mouse glial cultures, and on myelination and remyelination in organotypic cultures. Three molecules, edaravone, 5-methyl-7-methoxyisoflavone and lovastatin, gave positive results in all screening tiers. We validated the results by retesting independent stocks of the compounds, analyzing their purity, and performing dose-response curves. To identify the chemical features that may be modified to enhance the compounds' activity, we tested chemical analogs and identified, for edaravone, the functional groups that may be essential for its activity. Among the selected remyelinating candidates, edaravone appears to be of strong interest, also considering that this drug has been approved as a neuroprotective agent for acute ischemic stroke and amyotrophic lateral sclerosis in Japan.

Time-course changes of nLDL-induced erectile dysfunction

Hyperlipidemia is an important risk factor for atherosclerosis and is frequently seen in patients with erectile dysfunction (ED). This study was designed to evaluate whether the acute effect of native low-density lipoprotein (nLDL) on intracavernosal pressure (ICP) is reversible and related to plasma asymmetrical dimethylarginine (ADMA), endogenous inhibition of endothelial nitric oxide synthase (eNOS) levels and eNOS expression in cavernous tissues. Hyperlipidemia was induced by a single dose of intravenous 4 mg kg^-1 nLDL. Experiments were performed 72 h (72H), 2 weeks (2W) and 8 weeks (8W) after nLDL injection. Endothelium-dependent relaxations, the ratio of ICP to mean arterial pressure (MAP; ICP/MAP), plasma ADMA levels and eNOS mRNA and protein levels were evaluated. The ICP/MAP ratio decreased in both the 2W and 8W groups. Endothelium-dependent relaxation responses to acetylcholine in the rat thoracic aorta were damaged in the 8W group. Plasma ADMA levels increased in the 8W group. mRNA expression of eNOS decreased in a time-dependent manner, whereas the protein expression increased. These results suggest that acute nLDL injection-induced impairments in erectile functions during an 8-week period are irreversible and might be related to an increase in ADMA levels and changes in the regulation of the eNOS/NO pathway.

Retinal Diseases Associated with Oxidative Stress and the Effects of a Free Radical Scavenger (Edaravone)

Oxidative stress plays a pivotal role in developing and accelerating retinal diseases including age-related macular degeneration (AMD), glaucoma, diabetic retinopathy (DR), and retinal vein occlusion (RVO). An excess amount of reactive oxygen species (ROS) can lead to functional and morphological impairments in retinal pigment epithelium (RPE), endothelial cells, and retinal ganglion cells (RGCs). Here we demonstrate that edaravone, a free radical scavenger, decreased apoptotic cell death, oxidative damage to DNA and lipids, and angiogenesis through inhibiting JNK and p38 MAPK pathways in AMD, glaucoma, DR, and RVO animal models. These data suggest that the therapeutic strategy for targeting oxidative stress may be important for the treatment of these ocular diseases, and edaravone may be useful for treating retinal diseases associated with oxidative stress.

Edaravone Improves Functional and Structural Outcomes in Animal Models of Focal Cerebral Ischemia: A Systematic Review

Edaravone has been used in patients with acute ischemic stroke in Japan for over 10 years but does not have marketing authorization in Europe or America. Either patients in Europe and America are not receiving an effective treatment, or those in Asia are being given a treatment which is not effective. Finding out which of these is true will require further clinical trials, and a better understanding of its efficacy in animal models may help inform the design of those trials so that it might be tested under conditions where there is the greatest prospect of success. We systematically reviewed the efficacy of edaravone in animal models of focal ischemia and summarized data using weighted mean difference DerSimonian and Laird random-effects modeling. We used stratified meta-analysis and metaregression to assess the influence of study design and methodological quality. We identified 49 experiments describing outcome in 814 animals; 30 experiments (519 animals) reported functional and 35 experiments (503 animals) reported structural outcome. Edaravone improved functional and structural outcome by 30.3% (95% confidence interval 23.4–37.2%) and 25.5% (95% confidence interval, 21.1–29.9%), respectively. For functional outcome, there was an inverse relationship between study quality and effect size ( P < 0.0017). Effect sizes were larger in studies where randomization or blinded assessment was not reported. There was no evidence of publication bias. Edaravone is a promising treatment for stroke. However, because of the methodological weakness in current animal studies, no sufficient preclinical evidence is available to optimize the study design of clinical trials. Higher quality animal studies are expected to inform further clinical study.

The efficacy of edaravone (radicut), a free radical scavenger, for cardiovascular disease

Edaravone was originally developed as a potent free radical scavenger, and has been widely used to treat acute ischemic stroke in Japan since 2001. Free radicals play an important role in the pathogenesis of a variety of diseases, such as cardiovascular diseases and stroke. Therefore, free radicals may be targets for therapeutic intervention in these diseases. Edaravone shows protective effects on ischemic insults and inflammation in the heart, vessel, and brain in experimental studies. As well as scavenging free radicals, edaravone has anti-apoptotic, anti-necrotic, and anti-cytokine effects in cardiovascular diseases and stroke. Edaravone has preventive effects on myocardial injury following ischemia and reperfusion in patients with acute myocardial infarction. Edaravone may represent a new therapeutic intervention for endothelial dysfunction in the setting of atherosclerosis, heart failure, diabetes, or hypertension, because these diseases result from oxidative stress and/or cytokine-induced apoptosis. This review evaluates the potential of edaravone for treatment of cardiovascular disease, and covers clinical and experimental studies conducted between 1984 and 2013. We propose that edaravone, which scavenges free radicals, may offer a novel option for treatment of cardiovascular diseases. However, additional clinical studies are necessary to verify the efficacy of edaravone.

Cigarette smoke and LDL cooperate in reducing nitric oxide bioavailability in endothelial cells via effects on both eNOS and NADPH oxidase

The ubiquitous free radical nitric oxide (NO) plays an important role in many biological processes, including the regulation of both vascular tone and inflammatory response; however, its role in the effects of cigarette smoke exposure on atherosclerosis remains unclear. Our aim was to study the mechanisms of NO regulation in endothelial cells in response to cigarette smoke exposure in vitro. Using human umbilical vein endothelial cells (HUVEC), we have demonstrated that combining non-toxic concentrations of cigarette smoke bubbled through PBS (smoke-bubbled PBS [sbPBS]) with native LDL (nLDL) significantly reduces the amount of bioavailable NO. The effect is comparable to that seen with oxidized LDL (oxLDL), but has not been seen with sbPBS or nLDL alone. Mechanistic investigations showed that the combination of sbPBS+nLDL did not reduce the amount of endothelial nitric oxide synthase (eNOS), but did inhibit its enzymatic activity. Concomitantly, both sbPBS+nLDL and oxLDL significantly increased the production of reactive oxygen species (ROS) in the form of superoxide anions ((·)O(2)(-)) and peroxynitrite (ONOO(-)) in HUVEC. Selective inhibition of NADPH oxidase prevented this response. Incubation of sbPBS+nLDL revealed the formation of 7-ketocholesterol (7-KC) and 7-hydroxycholesterol, which are indicators for oxidative modification of LDL. This could explain the reported increase in circulatory levels of oxLDL in smokers. Our results suggest that reduction of functional NO in response to a combination of sbPBS+nLDL is secondary to both reduction of eNOS activity and stimulation of NADPH oxidase activity. Because sbPBS alone showed no effect on eNOS activity or ROS formation, nLDL should be included in cigarette-smoke-related mechanistic in vitro experiments on endothelial cells to be more reflective of the clinical situation.

Oxidized low-density lipoprotein inhibits nitric oxide-mediated coronary arteriolar dilation by up-regulating endothelial arginase I

Oxidized low-density lipoprotein (OxLDL) causes impairment of endothelium-dependent, nitric oxide (NO)-mediated vasodilation involving l-arginine deficiency. However, the underlying mechanism remains elusive. Since arginase and endothelial NO synthase (eNOS) share the substrate l-arginine, we hypothesized that OxLDL may reduce l-arginine availability to eNOS for NO production, and thus vasodilation, by up-regulating arginase. To test this hypothesis, porcine subepicardial arterioles (70-130 μm) were isolated for vasomotor study and for immunohistochemical detection of arginase and eNOS expressions. The coronary arterioles dilated dose-dependently to the endothelium-dependent NO-mediated vasodilator serotonin. This vasodilation was inhibited in the same manner by NOS inhibitor N(G)-nitro-l-arginine methyl ester and by lumenal OxLDL (0.5 mg protein/mL). The inhibitory effect of OxLDL was reversed after treating the vessels with either l-arginine (3 mM) or arginase inhibitor difluoromethylornithine (DFMO; 0.4 mM). Consistent with vasomotor alterations, OxLDL inhibited serotonin-induced NO release from coronary arterioles and this inhibition was reversed by DFMO. Vascular arginase activity was significantly elevated by OxLDL. Immunohistochemical analysis indicated that OxLDL increased arginase I expression in the vascular wall without altering eNOS expression. Taken together, these results suggest that OxLDL up-regulates arginase I, which contributes to endothelial dysfunction by reducing l-arginine availability to eNOS for NO production and thus vasodilation.

[Physical activity and endothelial dysfunction in type 2 diabetic patients: the role of nitric oxide and oxidative stress]

Type 2 diabetic patients have an increased level of systemic free radicals, which severely restrict the bioavailability of endothelium-derived nitric oxide (NO) and thus contribute to the development of an endothelial dysfunction. This review analyses the influence of physical training on molecular development mechanisms of the endothelial dysfunction and determines the significance of regular physical exercise for the endothelial function in type 2 diabetic patients. Systematic training reinforces the endogenic antioxidative capacity and results in a reduction in oxidative stress. Training - also combined with a change in diet - furthermore reduces hyperglycaemic blood sugar levels, thus curbing a major source of free radicals in diabetes. Moreover, physical exercise enhances vascular NO synthesis through an increased availability/activity of endothelial NO synthases (eNOS). Endurance, as well as resistance training with submaximal intensity or a combination of both forms of training is suitable to effectively improve the endothelial function in type 2 diabetic patients in the long term.

Decreased small dense LDL levels in Gilbert's syndrome

OBJECTIVE

To investigate the role of small dense low density lipoprotein cholesterol (sd-LDL-C) in the mechanism of decreased incidence of cardiovascular disease in Gilbert's syndrome (GS).

DESIGN AND METHODS

sd-LDL-C, ox-LDL, and high sensitive C reactive protein (hs-CRP) levels were investigated in subjects with GS (n=42) and compared to healthy controls (n=52).

RESULTS

Age, gender and body mass index (BMI) distributions were similar between the two groups. sd-LDL-C, ox-LDL and hs-CRP levels were lower in GS than the healthy controls (p<0.001, p<0.001 and p=0.001, respectively). Unconjugated bilirubin was negatively correlated with sd-LDL-C, ox-LDL and hs-CRP (r=-0.594, p<0.001; r=-0.249, p=0.016 and r=-0.373, p<0.001 respectively). In addition, sd-LDL-C was positively correlated with ox-LDL (r=0.307, p=0.003).

CONCLUSIONS

The findings of this preliminary study suggest that reduced sd-LDL-C, ox-LDL and hs-CRP levels may have a role in preventing atherosclerosis in subjects with GS.

Mechanisms of LDL oxidation

BACKGROUNDS

Many lines of evidence suggest that oxidized low-density lipoprotein (LDL) is implicated in the pathogenesis of atherosclerotic vascular diseases. This review summarizes a diversity of mechanisms proposed for LDL oxidation serving for the so-called "LDL oxidation hypothesis of atherogenesis".

METHODS AND RESULTS

We investigated the literature and our research results related to mechanisms of LDL oxidation and its atherogenesis. LDL oxidation is catalyzed by transition metal ions and several free radicals, and LDL is also oxidized by some oxidizing enzymes. In this way, LDL can be converted to a form that is recognized specifically by and with high affinity to macrophage scavenger receptors, leading to foam cell formation, the defining characteristic of fatty streak lesions.

CONCLUSIONS

Several pathways are involved in the promotion of LDL oxidation in vitro and in vivo, but it would appear that the physiologically relevant mechanisms of LDL oxidation are still imperfectly understood. The underlying mechanisms of LDL oxidation must be further explored to reveal appropriate ways for the diagnosis and treatment of atherosclerosis and its relevant diseases.

A critical assessment of edaravone acute ischemic stroke efficacy trials: is edaravone an effective neuroprotective therapy?

IMPORTANCE OF THE FIELD

Edaravone (Radicut) is a free radical scavenger marketed in Japan by Mitsubishi Tanabe Pharma Corp. to treat acute ischemic stroke (AIS) patients presenting within 24 h of the attack. Injectable edaravone ampoules (30 mg b.i.d., i.v., 14 days) were first approved on 23 May 2001. On 19 January 2010, as a new innovation, the Radicut BAG (Intravenous BAG) was approved by the Japanese Ministry of Health and Welfare. Efficacy of edaravone ranges from large significant clinical improvements to only modest improvements in clinical function measured using standard stroke scales when administered 6-72 h following an ischemic stroke. With almost 17 years of edaravone clinical experience, a few adverse events--including acute renal failure--have been noted.

WHAT THE READER WILL GAIN

This is the only article to date to critically review available clinical efficacy and toxicology data published in the literature to ascertain whether edaravone should be further pursued as a candidate for development worldwide.

AREAS COVERED IN THIS REVIEW

This review covers clinical studies carried out over the period 1993-2008.

TAKE HOME MESSAGE

Edaravone may be a useful neuroprotective agent to treat the > 15 million victims worldwide who are devastated by stroke annually. Additional clinical studies are necessary to verify the efficacy of edaravone.

Chrysanthemum morifolium Ramat. reduces the oxidized LDL-induced expression of intercellular adhesion molecule-1 and E-selectin in human umbilical vein endothelial cells

ETHNOPHARMACOLOGICAL RELEVANCE

The flower of Chrysanthemum morifolium Ramat. (CM) with antioxidant, cardiovascular protective and anti-inflammatory functions, has been widely used in China for hundreds of years as a healthy beverage and medicine.

AIMS OF THE STUDY

The purpose of the present study is to investigate the effects of HCM (a hot water extract of the flower of Chrysanthemum morifolium Ramat. [CM]), ECM (an ethanol extract of CM), and the abundant flavonoids apigenin and luteolin in CM on the oxidized LDL (oxLDL)-induced expression of ICAM-1 and E-selectin in human umbilical vein endothelial cells (HUVECs). The possible mechanism of these effects was also determined.

MATERIALS AND METHODS

MTT assay was for cell viability. Western blot was used for ICAM-1 and E-selection protein expression, and for activation of protein kinase B (PKB) and cAMP responsive element binding protein (CREB) proteins. Fluorescence flow cytometry was for ICAM-1 and E-selectin expression on cell surface. DCF-DA flow cytometric assay was used for reactive oxygen species (ROS) production.

RESULTS

HCM, ECM, apigenin, and luteolin dose-dependently inhibited ICAM-1 and E-selectin expression and adhesion of HL-60 by oxLDL. HCM, ECM, apigenin, and luteolin reversed the inhibition of phosphorylation of Akt and CREB by oxLDL; however, this reversion was abolished by wortmannin. In addition, wortmannin abrogated the inhibitory effects of CM extracts, apigenin and luteolin on adhesion molecule expression. The ROS scavenging capability of HCM, ECM, apigenin, and luteolin proceeded dose-dependently in the presence of oxLDL.

CONCLUSION

CM is a plant with cardiovascular-protective potential and the inhibitory effects of CM on ICAM-1 and E-selectin expression are, at least partially, attributed to its antioxidant activity and modulation of the PI3K/Akt signaling pathway.

Edaravone, a free radical scavenger, protects components of the neurovascular unit against oxidative stress in vitro

The concept of the neurovascular unit suggests that to be successful, stroke therapies must protect all neuronal, glial and endothelial components in brain. In this study, we tested the efficacy of the free radical scavenger edaravone in three cellular models of oxidative stress. HT22 neuronal cells were subjected to oxidative stress using the standard glutamate-induced glutathione depletion model. Primary rat astrocytes were exposed to H(2)O(2). Oxidative stress was induced in human brain endothelial cells with sodium nitroprusside (SNP). Edaravone significantly reduced oxidative cell death in both HT22 neuronal cells and primary rat astrocytes in a dose-dependent manner. SNP did not kill brain endothelial cells but instead reduced their production of brain-derived neurotrophic factor (BDNF). Edaravone significantly ameliorated this response. These data suggest that free radical scavengers are effective in all cell types of the neurovascular unit, and should still be considered as a potential therapeutic approach for stroke.

Microsomal triglyceride transfer protein gene polymorphism strongly influences circulating malondialdehyde-modified low-density lipoprotein

Microsomal triglyceride transfer protein (MTP) plays a critical role in the assembly of lipoproteins. Therefore, we studied whether MTP gene polymorphisms are associated with atherosclerosis-promoting parameters, especially metabolic profiles and endothelial function, in healthy young men. One hundred one healthy men (mean age, 30.3 years) were studied. We analyzed the 2 promoter polymorphisms (-493G/T and -400A/T) of the MTP gene. Linkage disequilibrium analysis revealed a significant but incomplete linkage disequilibrium between the 2 polymorphisms (D' = 0.74). The -493T allele carriers (n = 26) showed marked increases in their levels of malondialdehyde-modified low-density lipoprotein (mean value, 135 vs 99 U/L in the G/G carriers; P = .003) and triglycerides (2.15 vs 1.16 mmol/L, P = .014), and reduced low-density lipoprotein particle size (259.2 vs 264.3 nm, P = .023), whereas there was no difference in apolipoproteins, insulin, adiponectin, homocysteine, folate, and endothelial function assessed using ultrasound measurement of brachial artery flow-mediated vasodilation. In contrast, the -400T allele carriers (n = 61) showed a reduced endothelial function (P = .044), accompanied by elevated apolipoprotein B levels in subjects with higher triglyceride levels. These results indicate that both promoter polymorphisms may be associated with the development of atherosclerosis and cardiovascular diseases, but that the mechanism responsible may be different.

A novel fluorescent assay for edaravone with aqueous functional CdSe quantum dots

Aqueous thiol-capped CdSe QDs with a narrow, symmetric emission were prepared under a low temperature. Based on the fluorescence enhancement of thiol-stabilized CdSe quantum dots (QDs) caused by edaravone, a simple, rapid and specific quantitative method was proposed to the edaravone determination. The concentration dependence of fluorescence intensity followed the binding of edaravone to surface of the thiol-capped CdSe QDs was effectively described by a modified Langmuir-type binding isotherm. Factors affecting the fluorescence detection for edaravone with thiol-stabilized CdSe QDs were studied, such as the effect of pH, reaction time, the concentration of CdSe QDs and so on. Under the optimal conditions, the calibration plot of C/(I-I(0)) with concentration of edaravone was linear in the range of (1.45-17.42) microg/mL (0.008-0.1 micromol/L) with correlation coefficient of 0.998. The limit of detection (LOD) (3sigma/kappa) was 0.15 microg/mL (0.0009 micromol/mL). Possible interaction mechanism was discussed.

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.

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.

Clinical analysis of 207 patients who developed renal disorders during or after treatment with edaravone reported during post-marketing surveillance

BACKGROUND

The post-marketing surveillance of edaravone has reported serious adverse reactions, including renal and hepatic disorders. Renal disorders were the most frequently reported serious/important adverse reactions, which led to the evaluation of their causation by edaravone, their severity, and the recovery of renal function.

METHODS

A retrospective review was carried out of 207 Japanese patients with acute stroke who developed renal disorders on edaravone treatment.

RESULTS

No particular factor other than edaravone was found as a possible cause of the renal disorders in 17 patients (8.2%). In 91.8% of the patients evaluated, factors other than edaravone were associated with the development of renal disorders. Severe deterioration of systemic status (e.g., a severe infection or a decrease in blood pressure) was considered to be a highly probable cause of renal disorders that occurred before or during treatment with edaravone in 135 patients (65.2%). Fifty-nine patients (28.5%) underwent blood purification treatment (BPT). In the remaining 148 patients without BPT, the peak serum creatinine (SCr) level during follow-up was 3 mg/dl or more in 93 patients (44.9%) and less than 3 mg/dl in 55 patients (26.6%). The severity of renal disorders was moderate to severe in 73.3% of the 207 patients, and renal function recovered in 43%.

CONCLUSIONS

Appropriate treatment of deteriorated systemic status and the discontinuation of edaravone administration following the early discovery of renal disorders are recommended to reduce the development of severe renal disorders during edaravone treatment. The precise role(s) of edaravone in the pathogenesis of renal disorders should be evaluated in the future.

Plasma levels of nitric oxide and stroke outcome

Production of reactive oxygen species after cerebral blood flow disruption may enhance tissue damage through multiple molecular pathways. Changes in nitric oxide (NO) metabolism and oxidative stress status were investigated in 47 patients with ischemic stroke by measuring plasma nitric oxide (NO) and peroxynitrite (ONOO(-)) levels.A correlation was sought between these two parameters and i) baseline stroke severity based on the National Institute of Health stroke scale (NIHSS) and ii) neurological outcome in terms of NIHSS changes from entry (T(0)) to 30 days after symptom onset (T(1)). The control group consisted of 30 age- and sex-matched healthy subjects. Mean plasma levels of ONOO(-) (arbitrary fluorescence number +/- SD) were significantly higher in patients (7.70 +/- 1.71 vs 5.35 +/- 0.69, p < 0.001), whereas mean NO levels (nmol/mg protein) were significantly higher in controls (115.40 +/- 12.40 vs. 51.10 +/- 12.50, p < 0.001). Plasma ONOO(-) was significantly higher among patients with non-lacunar stroke (8.48 +/- 1.50 vs. 6.95 +/- 1.58 in those with lacunar stroke; p = 0.001), whereas NO levels were significantly higher among lacunar stroke patients (60.00 +/- 7.86, vs. 41.77 +/- 9.29 in patients with nonlacunar stroke; p < 0.001). Nitric oxide plasma levels were also associated with an unfavorable evolution in non-lacunar stroke, since a 10 unit increase in NO predicted a 1 point reduction in the NIHSS score at T1. Findings show that changes in NO metabolism may be considered as markers of brain injury in patients with ischemic stroke. Further work is needed to establish whether the amount of biochemical changes related to oxidative stress may influence outcome in these patients.

Edaravone preserves coronary microvascular endothelial function after ischemia/reperfusion on the beating canine heart in vivo

We examined whether edaravone (3-methyl-1-phenyl-2-pyrazolin-5-one), a free radical scavenger, exerts its protective effect on coronary microvessels after ischemia/reperfusion (I/R) in vivo. Ninety-minute coronary occlusion followed by reperfusion was performed in 16 open-chest dogs with and without edaravone administration. Coronary small artery (> or = 100 microm in size) and arteriolar (< 100 microm) vasodilation, in the presence of endothelium-dependent (acetylcholine) or -independent (papaverine) vasodilators, was directly observed using intravital microscopy before and after I/R. I/R impaired microvascular vasodilation in response to acetylcholine, whereas administration of edaravone preserved the response in microvessels of both sizes, but to a greater extent in the coronary small arteries. No significant changes were noted with papaverine administration. In the edaravone group, the fluorescent intensity from reactive oxygen species (ROS) was lower, whereas nitric oxide (NO) intensity was higher relative to controls in the microvessels of the ischemic area. In conclusion, edaravone preserves coronary microvascular endothelial function after I/R in vivo. These effects, which were NO-mediated, were attributed to the ROS scavenging properties of edaravone.

Advances in hemorrhagic stroke therapy: conventional and novel approaches

Treatments for spontaneous intracerebral, thrombolytic-induced and intraventricular hemorrhages (IVH) are still at the preclinical or early clinical investigational stages. There has been some renewed interest in the use of surgical evacuation surgery or thrombolytics to remove hematomas, but these techniques can be used only for specific types of brain bleeding. The STICH (Surgical Trial in Intracerebral Haemorrhage) clinical trials should provide some insight into the potential for such techniques to counteract hematoma-induced damage and subsequently, morbidity and mortality. More recently, clinical trials (ATACH [Antihypertensive Treatment in Acute Cerebral Hemorrhage] and INTERACT [Intensive Blood Pressure Reduction in Acute Cerebral Hemorrhage Trial]) have begun testing whether or not regulating blood pressure affects the well-being of hemorrhage patients, but the findings thus far have not conclusively demonstrated a positive result. More promising trials, such as the early stage CHANT (Cerebral Hemorrhagic And NXY-059 Treatment) and the late stage FAST (Factor VIIa for Acute Hemorrhagic Stroke Treatment), have addressed whether or not manipulating oxidative stress and components of the blood coagulation cascade can achieve an improved prognosis following spontaneous hemorrhages. However, CHANT was halted prematurely because although it showed that the spin trap agent NXY-059 was safe, it also demonstrated that the drug was ineffective in treating acute ischemic stroke. In addition, the recombinant activated factor VII FAST trial recently concluded with only modestly positive results. Despite a beneficial effect on the primary end point of reducing hemorrhage volume, controlling the coagulation cascade with recombinant factor VIIa did not decrease the mortality rate. Consequently, Novo Nordisk has abandoned further development of the drug for the treatment of intracerebral hemorrhaging. Even though progress in hemorrhage therapy that successfully reduces the escalating morbidity and mortality rate associated with brain bleeding is slow, perseverance and applied translational drug development will eventually be productive. The urgent need for such therapy becomes more evident in light of concerns related to uncontrolled high blood pressure in the general population, increased use of blood thinners by the elderly (e.g., warfarin) and thrombolytics by acute ischemic stroke patients, respectively. The future of drug development for hemorrhage may require a multifaceted approach, such as combining drugs with diverse mechanisms of action. Because of the substantial benefit of factor VIIa in reducing hemorrhage volume, it should be considered as a prime drug candidate included in combination therapy as an off-label use if the FAST trial proves that the risk of thromboembolic events is not increased with drug administration. Other promising drugs that may be considered in combination include uncompetitive NMDA receptor antagonists (such as memantine), antioxidants, metalloprotease inhibitors, statins and erythropoietin analogs, all of which have been shown to reduce hemorrhage and behavioral deficits in one or more animal models.

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 mimics sphingosine-1-phosphate-induced endothelial barrier enhancement in human microvascular endothelial cells

Edaravone is a potent scavenger of hydroxyl radicals and is quite successful in patients with acute cerebral ischemia, and several organ-protective effects have been reported. Treatment of human microvascular endothelial cells with edaravone (1.5 microM) resulted in the enhancement of transmonolayer electrical resistance coincident with cortical actin enhancement and redistribution of focal adhesion proteins and adherens junction proteins to the cell periphery. Edaravone also induced small GTPase Rac activation and focal adhesion kinase (FAK; Tyr(576)) phosphorylation associated with sphingosine-1-phosphate receptor type 1 (S1P(1)) transactivation. S1P(1) protein depletion by the short interfering RNA technique completely abolished edaravone-induced FAK (Tyr(576)) phosphorylation and Rac activation. This is the first report of edaravone-induced endothelial barrier enhancement coincident with focal adhesion remodeling and cytoskeletal rearrangement associated with Rac activation via S1P(1) transactivation. Considering the well-established endothelial barrier-protective effect of S1P, endothelial barrier enhancement as a consequence of S1P(1) transactivation may at least partly be the potent mechanisms for the organ-protective effect of edaravone and is suggestive of edaravone as a therapeutic agent against systemic vascular barrier disorder.

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.

Effect of chronic N-acetylcysteine treatment on the development of spontaneous hypertension

The imbalance between NO (nitric oxide) and ROS (reactive oxygen species) is an important factor in the development of hypertension. The aim of the present study was to determine the preventive and therapeutic effects of NAC (N-acetylcysteine) in SHRs (spontaneously hypertensive rats). Young and adult SHRs and WKY (Wistar-Kyoto) rats were treated with NAC (20 g/l in the drinking water). After 8 weeks of treatment, BP (blood pressure) and NOS (NO synthase) activity, conjugated dienes and GSH (reduced glutathione) in the kidney and left ventricle were determined. Protein expression of eNOS (endothelial NOS), inducible NOS and NF-kappaB (nuclear factor kappaB) were also determined in the left ventricle and kidney. Chronic NAC treatment partially attenuated the rise in BP in young SHRs (179+/-6 compared with 210+/-8 mmHg in untreated animals), but it had no significant effect on BP in adult SHRs. The antioxidant action of NAC, measured as a decrease of the concentration of conjugated dienes or inhibition of NF-kappaB expression, was greater in young than in adult SHRs. Similarly, eNOS protein expression was attenuated more in young than in adult SHRs, although NAC treatment increased NOS activity to a similar extent in both young and adult rats. In conclusion, both decreased ROS production and increased NOS activity appear to participate in the BP changes after NAC treatment in young SHRs. In adult SHRs with established hypertension, however, the secondary alterations (such as pronounced structural remodelling of resistance vessels) might attenuate the therapeutic effect of NAC.

Potent free radical scavenger, edaravone, suppresses oxidative stress-induced endothelial damage and early atherosclerosis

OBJECTIVE

Effects of potent free radical scavenger, edaravone, on oxidative stress-induced endothelial damage and early atherosclerosis were investigated using animal models and cultured cells.

METHODS AND RESULTS

Endothelial apoptosis was induced by 5-min intra-arterial exposure of a rat carotid artery with 0.01 mmol/L H(2)O(2). Edaravone treatment (10mg/kg i.p.) for 3 days suppressed endothelial apoptosis, as evaluated by chromatin staining of en face specimens at 24h, by approximately 40%. Similarly, edaravone dose-dependently inhibited H(2)O(2)-induce apoptosis of cultured endothelial cells in parallel with the inhibition of 8-isoprostane formation, 4-hydroxy-2-nonenal (4-HNE) accumulation and VCAM-1 expression. Next, apolipoprotein-E knockout mice were fed a high-cholesterol diet for 4 weeks with edaravone (10mg/kg i.p.) or vehicle treatment. Edaravone treatment decreased atherosclerotic lesions in the aortic sinus (0.18+/-0.01 to 0.09+/-0.01 mm(2), P<0.001) and descending aorta (5.09+/-0.86 to 1.75+/-0.41 mm(2), P<0.05), as evaluated by oil red O staining without influence on plasma lipid concentrations or blood pressure. Dihydroethidium labeling and cytochrome c reduction assay showed that superoxide anions in the aorta were suppressed by edaravone. Also, plasma 8-isoprostane concentrations and aortic nitrotyrosine, 4-HNE and VCAM-1 contents were decreased by edaravone treatment.

CONCLUSIONS

These results suggest that edaravone may be a useful therapeutic tool for early atherosclerosis, pending the clinical efficacy.

Neuroprotective effects of edaravone: a novel free radical scavenger in cerebrovascular injury

Recanalization and neuroprotection have been mainly targeted for the specific treatment of acute ischemic stroke. Free radicals play a crucial role in brain ischemic injury by exacerbating membrane damage through peroxidation of unsaturated fatty acids of cell membrane, leading to neuronal death and brain edema. Free radicals have been implicated in stroke pathophysiology as pivotal contributors to cell injury. Edaravone (3-methyl-1-phenyl-2-pyrazolin-5-one) is a novel potent free radical scavenger that has been clinically used to reduce the neuronal damage following ischemic stroke. Edaravone exerts neuroprotective effects by inhibiting endothelial injury and by ameliorating neuronal damage in brain ischemia. Edaravone provides the desirable features of NOS: it increases eNOS (beneficial NOS for rescuing ischemic stroke) and decreases nNOS and iNOS (detrimental NOS). Post- reperfusion brain edema and hemorrhagic events induced by thrombolytic therapy may be reduced by edaravone pretreatment. Increased productions of superoxide and NO in the brain after reperfusion and a concomitant surge in oxygen free radicals with increased NO during recirculation lead to formation of peroxynitrite, a superpotent radical. Edaravone, which inhibits oxidation and enhances NO production derived from increased eNOS expression, may improve and conserve cerebral blood flow without peroxynitrite generation during reperfusion. Clinical experience with edaravone suggests that this drug has a wide therapeutic time window. The combination therapy (a thrombolytic plus edaravone) is likely to target brain edema, reduce stroke death and improve the recovery from neurological deficits in stoke patients.