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

The design and synthesis of benzylpiperazine-based edaravone derivatives and their neuroprotective activities

New edaravone derivatives containing a benzylpiperazine moiety are designed and synthesized. The structures are characterized by 1H NMR, 13C NMR, and high-resolution mass spectrometry. The potential neuroprotective activities of the target compounds are evaluated in differentiated rat pheochromocytoma cells (PC12 cells) and in mice subjected to acute cerebral ischemia. Most of the target compounds showed neuroprotective activities both in vivo and in vitro, especially 1-(4-(4-fluorobenzyl) piperazin-1-yl)-2-(4-(5-hydroxy-3-methyl-1 H-pyrazol-1-yl)phenoxy)ethanone and 1-(4-(4-nitrobenzyl)piperazin-1-yl)-2-(4-(5-hydroxy-3-methyl-1 H-pyrazol-1-yl)phenoxy)ethanone, which displayed significant protective effects on cell viability against damage caused by H2O2, and remarkably prolonged the survival time of mice subjected to acute cerebral ischemia and decreased the mortality rate at all doses. These compounds represent lead compounds for the further discovery of neuroprotective agents for treating cerebral ischemic stroke. Molecular docking studies and basic structure–activity relationships are also presented.

Edaravone Attenuated Angiotensin II-Induced Atherosclerosis and Abdominal Aortic Aneurysms in Apolipoprotein E-Deficient Mice

Background: The aim of the study was to define whether edaravone, a free-radical scavenger, influenced angiotensin II (AngII)-induced atherosclerosis and abdominal aortic aneurysms (AAAs) formation. Methods: Male apolipoprotein E-deficient mice (8–12 weeks old) were fed with a normal diet for 5 weeks. Either edaravone (10 mg/kg/day) or vehicle was injected intraperitoneally for 5 weeks. After 1 week of injections, mice were infused subcutaneously with either AngII (1000 ng/kg/min, n = 16–17 per group) or saline (n = 5 per group) by osmotic minipumps for 4 weeks. Results: AngII increased systolic blood pressure equivalently in mice administered with either edaravone or saline. Edaravone had no effect on plasma total cholesterol concentrations and body weights. AngII infusion significantly increased ex vivo maximal diameters of abdominal aortas and en face atherosclerosis but was significantly attenuated by edaravone administration. Edaravone also reduced the incidence of AngII-induced AAAs. In addition, edaravone diminished AngII-induced aortic MMP-2 activation. Quantitative RT-PCR revealed that edaravone ameliorated mRNA abundance of aortic MCP-1 and IL-1β. Immunostaining demonstrated that edaravone attenuated oxidative stress and macrophage accumulation in the aorta. Furthermore, edaravone administration suppressed thioglycolate-induced mice peritoneal macrophages (MPMs) accumulation and mRNA abundance of MCP-1 in MPMs in male apolipoprotein E-deficient mice. In vitro, edaravone reduced LPS-induced mRNA abundance of MCP-1 in MPMs. Conclusions: Edaravone attenuated AngII-induced AAAs and atherosclerosis in male apolipoprotein E-deficient mice via anti-oxidative action and anti-inflammatory effect.

Promising Antioxidative Effect of Berberine in Cardiovascular Diseases

Berberine (BBR), an important quaternary benzylisoquinoline alkaloid, has been used in Chinese traditional medicine for over 3,000 years. BBR has been shown in both traditional and modern medicine to have a wide range of pharmacological actions, including hypoglycemic, hypolipidemic, anti-obesity, hepatoprotective, anti-inflammatory, and antioxidant activities. The unregulated reaction chain induced by oxidative stress as a crucial mechanism result in myocardial damage, which is involved in the pathogenesis and progression of many cardiovascular diseases (CVDs). Numerous researches have established that BBR protects myocardium and may be beneficial in the treatment of CVDs. Given that the pivotal role of oxidative stress in CVDs, the pharmacological effects of BBR in the treatment and/or management of CVDs have strongly attracted the attention of scholars. Therefore, this review sums up the prevention and treatment mechanisms of BBR in CVDs from in vitro, in vivo, and finally to the clinical field trials timely. We summarized the antioxidant stress of BBR in the management of coronary atherosclerosis and myocardial ischemia/reperfusion; it also analyzes the pathogenesis of oxidative stress in arrhythmia and heart failure and the therapeutic effects of BBR. In short, BBR is a hopeful drug candidate for the treatment of CVDs, which can intervene in the process of CVDs from multiple angles and different aspects. Therefore, if we want to apply it to the clinic on a large scale, more comprehensive, intensive, and detailed researches are needed to be carried out to clarify the molecular mechanism and targets of BBR.

Kidney-Targeted Redox Scavenger Therapy Prevents Cisplatin-Induced Acute Kidney Injury

Cisplatin-induced acute kidney injury (CI-AKI) is a significant co-morbidity of chemotherapeutic regimens. While this condition is associated with substantially lower survival and increased economic burden, there is no pharmacological agent to effectively treat CI-AKI. The disease is hallmarked by acute tubular necrosis of the proximal tubular epithelial cells primarily due to increased oxidative stress. We investigated a drug delivery strategy to improve the pharmacokinetics of an approved therapy that does not normally demonstrate appreciable efficacy in CI-AKI, as a preventive intervention. In prior work, we developed a kidney-selective mesoscale nanoparticle (MNP) that targets the renal proximal tubular epithelium. Here, we found that the nanoparticles target the kidneys in a mouse model of CI-AKI with significant damage. We evaluated MNPs loaded with the reactive oxygen species scavenger edaravone, currently used to treat stroke and ALS. We found a marked and significant therapeutic benefit with edaravone-loaded MNPs, including improved renal function, which we demonstrated was likely due to a decrease in tubular epithelial cell damage and death imparted by the specific delivery of edaravone. The results suggest that renal-selective edaravone delivery holds potential for the prevention of acute kidney injury among patients undergoing cisplatin-based chemotherapy.

Eicosanoid blood vessel regulation in physiological and pathological states

Arachidonic acid can be metabolized in blood vessels by three primary enzymatic pathways; cyclooxygenase (COX), lipoxygenase (LO), and cytochrome P450 (CYP). These eicosanoid metabolites can influence endothelial and vascular smooth muscle cell function. COX metabolites can cause endothelium-dependent dilation or constriction. Prostaglandin I2 (PGI2) and thromboxane (TXA2) act on their respective receptors exerting opposing actions with regard to vascular tone and platelet aggregation. LO metabolites also influence vascular tone. The 12-LO metabolite 12S-hydroxyeicosatrienoic acid (12S-HETE) is a vasoconstrictor whereas the 15-LO metabolite 11,12,15-trihydroxyeicosatrienoic acid (11,12,15-THETA) is an endothelial-dependent hyperpolarizing factor (EDHF). CYP enzymes produce two types of eicosanoid products: EDHF vasodilator epoxyeicosatrienoic acids (EETs) and the vasoconstrictor 20-HETE. The less-studied cross-metabolites generated from arachidonic acid metabolism by multiple pathways can also impact vascular function. Likewise, COX, LO, and CYP vascular eicosanoids interact with paracrine and hormonal factors such as the renin-angiotensin system and endothelin-1 (ET-1) to maintain vascular homeostasis. Imbalances in endothelial and vascular smooth muscle cell COX, LO, and CYP metabolites in metabolic and cardiovascular diseases result in vascular dysfunction. Restoring the vascular balance of eicosanoids by genetic or pharmacological means can improve vascular function in metabolic and cardiovascular diseases. Nevertheless, future research is necessary to achieve a more complete understanding of how COX, LO, CYP, and cross-metabolites regulate vascular function in physiological and pathological states.

Effect of edaravone on pregnant mice and their developing fetuses subjected to placental ischemia

Growing evidence indicates that reduced uterine perfusion pressure (RUPP) triggers the cascade of events leading to preeclampsia. Edaravone is a powerful free radical scavenger used for the treatment of ischemia/reperfusion diseases due to its anti-oxidative stress and anti-inflammatory properties. Here we investigate the effect of edaravone (3 mg/kg) on different maternal and fetal outcomes of RUPP-induced placental ischemia mice model. RUPP surgery was performed on gestation day (GD) 13 followed by edaravone injection from GD14 to GD18, sacrifice day. The results showed that edaravone injection significantly decreased the maternal blood pressure (113.2 ± 2.3 mmHg) compared with RUPP group (131.5 ± 1.9 mmHg). Edaravone increased fetal survival rate (75.4%) compared with RUPP group (54.4%), increased fetal length, weights, and feto-placental ratio (7.2 and 5.7 for RUPP and RUPP-Edaravone groups, respectively) compared with RUPP group. In addition, RUPP resulted in many fetal morphological abnormalities as well as severe delayed ossification, however edaravone decreased the morphological abnormalities and increased the ossification of the fetal endoskeleton. Edaravone improved the histopathological structure of the maternal kidney and heart as well as decreased the elevated blood urea and creatinine levels (31.5 ± 0.15 mg/dl (RUPP), 25.6 ± 0.1 mg/dl (RUPP+edaravone) for urea and 5.4 ± 0.1 mg/dl (RUPP), 3.5 ± 0.1 mg/dl (RUPP+edaravone) for creatinine) and decreased cleaved caspase-3 expression in the maternal kidney. In conclusion, this study demonstrated that our RUPP mice model recapitulated preeclampsia symptoms and edaravone injection ameliorated most of these abnormalities suggesting its effectiveness and potential application in preeclampsia treatment regimes.

The Beneficial Effects of Saffron Extract on Potential Oxidative Stress in Cardiovascular Diseases

Saffron is commonly used in traditional medicines and precious perfumes. It contains pharmacologically active compounds with notably potent antioxidant activity. Saffron has a variety of active components, including crocin, crocetin, and safranal. Oxidative stress plays an important role in many cardiovascular diseases, and its uncontrolled chain reaction is related to myocardial injury. Numerous studies have confirmed that saffron exact exhibits protective effects on the myocardium and might be beneficial in the treatment of cardiovascular disease. In view of the role of oxidative stress in cardiovascular disease, people have shown considerable interest in the potential role of saffron extract as a treatment for a range of cardiovascular diseases. This review analyzed the use of saffron in the treatment of cardiovascular diseases through antioxidant stress from four aspects: antiatherosclerosis, antimyocardial ischemia, anti-ischemia reperfusion injury, and improvement in drug-induced cardiotoxicity, particularly anthracycline-induced. Although data is limited in humans with only two clinically relevant studies, the results of preclinical studies regarding the antioxidant stress effects of saffron are promising and warrant further research in clinical trials. This review summarized the protective effect of saffron in cardiovascular diseases and drug-induced cardiotoxicity. It will facilitate pharmacological research and development and promote utilization of saffron.

4-Hydroxyl-2-Nonenal Localized Expression Pattern in Retrieved Clots is Associated with Large Artery Atherosclerosis in Stroke Patients

OBJECTIVES

The relationship between stroke etiology and clot pathology remains controversial.

MATERIALS AND METHODS

We performed histological analysis of clots retrieved from 52 acute ischemic stroke patients using hematoxylin and eosin staining and immunohistochemistry (CD42b and oxidative/hypoxic stress markers). The correlations between clot composition and the stroke etiological group (i.e., cardioembolic, cryptogenic, or large artery atherosclerosis) were assessed.

RESULTS

Of the 52 clots analyzed, there were no significant differences in histopathologic composition (e.g., white blood cells, red blood cells, fibrin, and platelets) between the 3 etiological groups (P = .92). By contrast, all large artery atherosclerosis clots showed a localized pattern with the oxidative stress marker 4-hydroxyl-2-nonenal (P < .01). From all 52 clots, 4-hydroxyl-2-nonenal expression patterns were localized in 28.8% of clots, diffuse in 57.7% of clots, and no signal in 13.5% of clots.

CONCLUSIONS

A localized pattern of 4-hydroxyl-2-nonenal staining may be a novel and effective marker for large artery atherosclerosis (sensitivity 100%, specificity 82%).

Lipid Peroxidation in Atherosclerotic Cardiovascular Diseases

Significance: Atherosclerotic cardiovascular diseases (ACVDs) continue to be a primary cause of mortality worldwide in adults aged 35-70 years, occurring more often in countries with lower economic development, and they constitute an ever-growing global burden that has a considerable socioeconomic impact on society. The ACVDs encompass diverse pathologies such as coronary artery disease and heart failure (HF), among others. Recent Advances: It is known that oxidative stress plays a relevant role in ACVDs and some of its effects are mediated by lipid oxidation. In particular, lipid peroxidation (LPO) is a process under which oxidants such as reactive oxygen species attack unsaturated lipids, generating a wide array of oxidation products. These molecules can interact with circulating lipoproteins, to diffuse inside the cell and even to cross biological membranes, modifying target nucleophilic sites within biomolecules such as DNA, lipids, and proteins, and resulting in a plethora of biological effects. Critical Issues: This review summarizes the evidence of the effect of LPO in the development and progression of atherosclerosis-based diseases, HF, and other cardiovascular diseases, highlighting the role of protein adduct formation. Moreover, potential therapeutic strategies targeted at lipoxidation in ACVDs are also discussed. Future Directions: The identification of valid biomarkers for the detection of lipoxidation products and adducts may provide insights into the improvement of the cardiovascular risk stratification of patients and the development of therapeutic strategies against the oxidative effects that can then be applied within a clinical setting.

Protective effect of edaravone against radiation-induced ovarian injury: a histopathological and immunohistochemical evaluation in an experimental rat model

PURPOSE

We aimed to evaluate the protective effect of edaravone on radiation-induced ovarian damage in an experimental rat model.

METHODS

Thirty-two Wistar albino female rats were randomly divided into four groups. Group 1: control, no treatment, and radiation was applied throughout the study; Group 2: sham, only radiation was applied; Group 3: 45 mg/kg edaravone and radiation were applied; Group 4: 450 mg/kg edaravone and radiation were applied. Edaravone was administered intraperitoneally 30 min before radiotherapy (5 Gy). Two days after radiation exposure, the rats were sacrificed and the ovaries were removed. Histologic changes under light microscopy and immunoreactivity for anti-caspase-3 were noted and compared between the four groups.

RESULTS

There was a statistically significant difference in follicle counts, vascular congestion, edema, cytoplasmic vacuolization, hemorrhage, and interstitial cell degeneration between the groups. Radiation causes deterioration in most histopathological parameters. Administration of edaravone at different doses seems to reverse these alterations and alleviate the injury. Antioxidant defense mechanisms appear to be enhanced by edaravone as shown by histopathologically and decreased apoptosis by reducing the expression of anti-caspase-3 activity as demonstrated immunohistochemically.

CONCLUSION

This is the first study evaluating the protective effects of edaravone on radiation-induced ovarian damage. Edaravone decreased the follicular apoptosis and attenuates the radiation-induced ovarian damage in rats.

Scavenging of reactive dicarbonyls with 2-hydroxybenzylamine reduces atherosclerosis in hypercholesterolemic Ldlr-/- mice

Lipid peroxidation generates reactive dicarbonyls including isolevuglandins (IsoLGs) and malondialdehyde (MDA) that covalently modify proteins. Humans with familial hypercholesterolemia (FH) have increased lipoprotein dicarbonyl adducts and dysfunctional HDL. We investigate the impact of the dicarbonyl scavenger, 2-hydroxybenzylamine (2-HOBA) on HDL function and atherosclerosis in Ldlr^−/− mice, a model of FH. Compared to hypercholesterolemic Ldlr^−/− mice treated with vehicle or 4-HOBA, a nonreactive analogue, 2-HOBA decreases atherosclerosis by 60% in en face aortas, without changing plasma cholesterol. Ldlr^−/− mice treated with 2-HOBA have reduced MDA-LDL and MDA-HDL levels, and their HDL display increased capacity to reduce macrophage cholesterol. Importantly, 2-HOBA reduces the MDA- and IsoLG-lysyl content in atherosclerotic aortas versus 4-HOBA. Furthermore, 2-HOBA reduces inflammation and plaque apoptotic cells and promotes efferocytosis and features of stable plaques. Dicarbonyl scavenging with 2-HOBA has multiple atheroprotective effects in a murine FH model, supporting its potential as a therapeutic approach for atherosclerotic cardiovascular disease.

Hypercholesterolemia is associated with lipid peroxidation induced reactive dicarbonyl adducts. Here the authors show that the dicarbonyl scavenger, 2-hydroxybenzylamine(2-HOBA), decreases reactive dicarbonyl modifications of LDL and HDL, improves HDL function, reduces atherosclerosis and promotes features of stable plaques in a mouse model of hypercholestrolemia.

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.

MicroRNAs 342 and 450 together with NOX-4 activity and their association with coronary artery disease in diabetes

BACKGROUND

Dysregulation of miRNAs has been associated with many clinical conditions, including coronary artery disease (CAD). MiRNAs roles in patients with type 2 diabetes mellitus (T2D) with or without CAD, however, have not been clearly understood. Therefore we studied the expression of miRNAs 342 and 450 and the activity of the NADPH oxidase 4 (NOX-4), and their association with anthropometric and biochemical parameters of hyperglycaemia and dyslipidaemia.

SUBJECTS AND METHODS

Blood was collected from 200 outpatient subjects, divided into four groups of 50 individuals including control, T2D, CAD, and T2D with CAD. CAD was further divided based on CAD with angina, CAD clots, and CAD ischaemia to differentiate the primary cause of CAD. We measured the miRNAs 342 and 450 expression and NOX-4 activity, in addition to routine parameters.

RESULTS

The expression of miRNAs 342 and 450 and NOX-4 activity was significantly different between groups. Furthermore, they presented significant correlations with routine parameters, providing evidence of a potentially beneficial role in stratifying the risk for CAD in patients with T2D.

CONCLUSION

The results of this study suggest that the expression of miRNAs 342 and 450 and NOX-4 activity may help identify those individuals with T2D at high risk for developing CAD as well as the prognosis in those with established CAD.

Helicobacter pylori infection combined with non-alcoholic fatty liver disease increase the risk of atherosclerosis: Focus in carotid artery plaque

Atherosclerosis has severe consequences on human health. Carotid artery plaques are a condition typically caused by atherosclerosis. Previous studies showed that nonalcoholic fatty liver disease (NAFLD) and Helicobacter pylori (H pylori) are risks factors for carotid artery plaque formation. We hypothesize that the combination of NAFLD with H pylori infection increases the risk of carotid artery plaque formation.A total of 4669 subjects aged > 40 years who underwent routine health checkups between January 2006 and December 2015 were retrospectively reviewed. A serial examination, including abdominal ultrasound, carotid artery ultrasound and esophago-gastroduodenoscopy (EGD), and biopsy urease testing, was conducted.In total, 2402 subjects were enrolled. There were no differences in H pylori infection status among patients with or without NAFLD. There was a trend of more participants with both NAFLD and H pylori infection (number [N]=583) presenting carotid artery plaque (N = 187,32.08%) than participants without NAFLD and H pylori infection (N = 589) who presented plaque formation (N = 106, 18.00%). Participants who had both H pylori infection and NAFLD had the highest risk of any carotid artery plaque (odds ratio [OR], 1.93; 95% confidence interval [CI], 1.413-2.636) based on a multivariate logistic regression analysis. This analysis also showed that age >60 years, male sex, low-density lipoprotein (LDL) >130 mg/dL, and H pylori infection were independent risk factors for concomitant NAFLD and carotid artery plaque formation.The combination of H pylori infection and NAFLD increases carotid artery plaque formation. H pylori eradication and NAFLD control may be warranted to prevent carotid artery plaque formation.

Endotoxinemia contributes to steatosis, insulin resistance and atherosclerosis in chronic hepatitis C: the role of pro-inflammatory cytokines and oxidative stress

PURPOSE

Endotoxin is a component of the outer membrane of gram-negative bacteria that live in the intestine. Endotoxinemia is reported in non-alcoholic fatty liver disease and in cirrhotic patients, causing various biological and clinical effects in the host. It is not known whether endotoxinemia occurs in chronic hepatitis C patients (CHC), therefore we evaluated the occurrence of endotoxinemia and its effect on inflammation, liver damage, insulin resistance (IR) and atherosclerosis.

METHODS

Consecutive CHC patients assessed by liver biopsy were enrolled. Endotoxinemia was evaluated by LAL test. IR was estimated by HOMA-IR. Serum TNF-α, IL-8, adiponectin and MCP-1 were measured with ELISA tests. Oxidative stress was estimated by circulating IgG against malondialdehyde adducts with human serum albumin (MDA-HAS). Carotid atherosclerosis was assessed by ultrasonography.

RESULTS

Endotoxinemia was found in 60% of the 126 patients enrolled. A serum level-dependent association between endotoxinemia, steatosis (p < 0.001) and HOMA-IR (p < 0.006) was observed. Patients with endotoxinemia showed significant increase in TNF-α and IL8 levels. TNF-α correlated with steatosis (p <  0.001) and HOMA-IR (p < 0.03), whereas IL8 correlated with steatosis (p =  <0.001), TNF-α (p < 0.04) and atherosclerosis (p < 0.01). The highest levels of endotoxinemia were associated with oxidative stress and a higher prevalence of carotid atherosclerosis. Multivariate logistic regression analysis showed that the independent factors associated with endotoxinemia were hepatic steatosis, HOMA-IR, IL8 and MDA-HAS.

CONCLUSIONS

Endotoxinemia occurs with high frequency in CHC patients and contributes to the development of hepatic steatosis, IR and atherosclerosis through increased pro-inflammatory cytokines and oxidative stress. Anti-endotoxin treatment could be of clinical relevance.

Molecular Mechanisms behind Free Radical Scavengers Function against Oxidative Stress

Accumulating evidence shows that oxidative stress is involved in a wide variety of human diseases: rheumatoid arthritis, Alzheimer's disease, Parkinson's disease, cancers, etc. Here, we discuss the significance of oxidative conditions in different disease, with the focus on neurodegenerative disease including Parkinson's disease, which is mainly caused by oxidative stress. Reactive oxygen and nitrogen species (ROS and RNS, respectively), collectively known as RONS, are produced by cellular enzymes such as myeloperoxidase, NADPH-oxidase (nicotinamide adenine dinucleotide phosphate-oxidase) and nitric oxide synthase (NOS). Natural antioxidant systems are categorized into enzymatic and non-enzymatic antioxidant groups. The former includes a number of enzymes such as catalase and glutathione peroxidase, while the latter contains a number of antioxidants acquired from dietary sources including vitamin C, carotenoids, flavonoids and polyphenols. There are also scavengers used for therapeutic purposes, such as 3,4-dihydroxyphenylalanine (L-DOPA) used routinely in the treatment of Parkinson's disease (not as a free radical scavenger), and 3-methyl-1-phenyl-2-pyrazolin-5-one (Edaravone) that acts as a free radical detoxifier frequently used in acute ischemic stroke. The cell surviving properties of L-DOPA and Edaravone against oxidative stress conditions rely on the alteration of a number of stress proteins such as Annexin A1, Peroxiredoxin-6 and PARK7/DJ-1 (Parkinson disease protein 7, also known as Protein deglycase DJ-1). Although they share the targets in reversing the cytotoxic effects of H₂O₂, they seem to have distinct mechanism of function. Exposure to L-DOPA may result in hypoxia condition and further induction of ORP150 (150-kDa oxygen-regulated protein) with its concomitant cytoprotective effects but Edaravone seems to protect cells via direct induction of Peroxiredoxin-2 and inhibition of apoptosis.

Hypertriglyceridemic rats fed high fat diet as a model of metabolic syndrome

People with metabolic syndrome have higher risk of cardiovascular diseases then those without. The aim of the work was to investigate whether high fat diet administered to Prague hereditary hypertriglyceridemic (HTG) rats can induce signs of metabolic syndrome (MetS). Our results showed that HTG rats fed high fat diet (HTGch) had disturbed glucose metabolism and also lipid metabolism - increased serum triacylglycerols (TAG), total cholesterol (Ch), low-density lipoprotein-Ch (LDL-Ch), and decreased high-density lipoprotein-Ch (HDL-Ch). Their livers proved markers of developing steatosis. Moreover, HTGch had increased blood pressure, yet the vascular endothelium was not significantly damaged. All these changes were accompanied with oxidative stress and tissue damage identified as increased liver concentrations of thiobarbituric acid reactive substances (TBARS) and activity of the lysosomal enzyme N-acetyl-D-glucosaminidase (NAGA). We assume that the model used may be suitable for the study of MetS with no evidence of obesity. Prolongation of the high fat diet duration might have a major impact on all parameters tested, especially on vascular endothelial function.

Biogenic Aldehydes as Therapeutic Targets for Cardiovascular Disease

Aldehydes are continuously formed in biological systems through enzyme-dependent and spontaneous oxidation of lipids, glucose, and primary amines. These highly reactive, biogenic electrophiles can become toxic via covalent modification of proteins, lipids and DNA. Thus, agents that scavenge aldehydes through conjugation have therapeutic value for a number of major cardiovascular diseases. Several commonly-prescribed drugs (e.g., hydralazine) have been shown to have potent aldehyde-conjugating properties which may contribute to their beneficial effects. Herein, we briefly describe the major sources and toxicities of biogenic aldehydes in cardiovascular system, and provide an overview of drugs that are known to have aldehyde-conjugating effects. Some compounds of phytochemical origin, and histidyl-dipeptides with emerging therapeutic value in this area are also discussed.

Edaravone protects against hyperosmolarity-induced oxidative stress and apoptosis in primary human corneal epithelial cells

An increase in the osmolarity of tears induced by excessive evaporation of the aqueous tear phase is a major pathological mechanism behind dry eye. Exposure of epithelial cells on the surface of the human eye to hyperosmolarity leads to oxidative stress, mitochondrial dysfunction, and apoptosis. Edaravone, a hydroxyl radical scavenging agent, is clinically used to reduce neuronal damage following ischemic stroke. In this study, we found that treatment with hyperosmotic media at 400 and 450 mOsM increased the levels of ROS and mitochondrial oxidative damage, which were ameliorated by edaravone treatment in a dose-dependent manner. We also found that edaravone could improve mitochondrial function in HCEpiCs by increasing the levels of ATP and mitochondrial membrane potential. MTT and LDH assays indicated that edaravone could attenuate hyperosmolarity-induced cell death. It was found that edaravone prevented apoptosis by decreasing the level of cleaved caspase-3, and attenuating the release of cytochrome C. Mechanistically, we found that edaravone augmented the expression of Nrf2 and its target genes, such as HO-1, GPx-1, and GCLC.

Edaravone injection reverses learning and memory deficits in a rat model of vascular dementia

Edaravone is a novel free radical scavenger that exerts neuroprotective effects by inhibiting endothelial injury and by ameliorating neuronal damage in brain ischemia. Recently, it was reported that edaravone could alleviate the pathology and cognitive deficits of Alzheimer's disease patients. However, its relevance to vascular dementia (VaD) is not clear. In this study, we partially occluded the bilateral carotid arteries of rats surgically to induce chronic cerebral hypoperfusion (CCH), a well-known rat model of VaD. Water maze and step-down inhibitory test were used to evaluate the memory deficit. The activities of superoxide dismutase (SOD) and lactate dehydrogenase (LDH), the content of malondialdehyde (MDA) and total reactive oxygen species were measured to evaluate the oxidative stress level. Western blot analysis was used to evaluate the synaptic protein expression. It was found that treatment with edaravone for a 5-week period was able to reverse both spatial and fear-memory deficits in rats with CCH. Edaravone significantly reduced the level of oxidative stress in the brains of rats with CCH by increasing SOD activity and decreasing the content of MDA, LDH, and total reactive oxygen species. Furthermore, edaravone treatment also restored the levels of multiple synaptic proteins in the hippocampi of rats with CCH. Our data provide direct evidence supporting the neuroprotective effects of edaravone in VaD. We propose that the alleviation of oxidative stress and restoration of synaptic proteins play important roles in neuroprotection.

Caspase-1 Inflammasome Activation Mediates Homocysteine-Induced Pyrop-Apoptosis in Endothelial Cells

RATIONALE

Endothelial injury is an initial mechanism mediating cardiovascular disease.

OBJECTIVE

Here, we investigated the effect of hyperhomocysteinemia on programed cell death in endothelial cells (EC).

METHODS AND RESULTS

We established a novel flow-cytometric gating method to define pyrotosis (Annexin V(-)/Propidium iodide(+)). In cultured human EC, we found that: (1) homocysteine and lipopolysaccharide individually and synergistically induced inflammatory pyroptotic and noninflammatory apoptotic cell death; (2) homocysteine/lipopolysaccharide induced caspase-1 activation before caspase-8, caspase-9, and caspase-3 activations; (3) caspase-1/caspase-3 inhibitors rescued homocysteine/lipopolysaccharide-induced pyroptosis/apoptosis, but caspase-8/caspase-9 inhibitors had differential rescue effect; (4) homocysteine/lipopolysaccharide-induced nucleotide-binding oligomerization domain, and leucine-rich repeat and pyrin domain containing protein 3 (NLRP3) protein caused NLRP3-containing inflammasome assembly, caspase-1 activation, and interleukin (IL)-1β cleavage/activation; (5) homocysteine/lipopolysaccharide elevated intracellular reactive oxygen species, (6) intracellular oxidative gradient determined cell death destiny as intermediate intracellular reactive oxygen species levels are associated with pyroptosis, whereas high reactive oxygen species corresponded to apoptosis; (7) homocysteine/lipopolysaccharide induced mitochondrial membrane potential collapse and cytochrome-c release, and increased B-cell lymphoma 2-associated X protein/B-cell lymphoma 2 ratio which were attenuated by antioxidants and caspase-1 inhibitor; and (8) antioxidants extracellular superoxide dismutase and catalase prevented homocysteine/lipopolysaccharide -induced caspase-1 activation, mitochondrial dysfunction, and pyroptosis/apoptosis. In cystathionine β-synthase-deficient (Cbs(-/-)) mice, severe hyperhomocysteinemia-induced caspase-1 activation in isolated lung EC and caspase-1 expression in aortic endothelium, and elevated aortic caspase-1, caspase-9 protein/activity and B-cell lymphoma 2-associated X protein/B-cell lymphoma 2 ratio in Cbs(-/-) aorta and human umbilical vein endothelial cells. Finally, homocysteine-induced DNA fragmentation was reversed in caspase-1(-/-) EC. Hyperhomocysteinemia-induced aortic endothelial dysfunction was rescued in caspase-1(-/-) and NLRP3(-/-) mice.

CONCLUSIONS

Hyperhomocysteinemia preferentially induces EC pyroptosis via caspase-1-dependent inflammasome activation leading to endothelial dysfunction. We termed caspase-1 responsive pyroptosis and apoptosis as pyrop-apoptosis.

Research advances in the relationship between nonalcoholic fatty liver disease and atherosclerosis

Nonalcoholic fatty liver disease (NAFLD) is a metabolic stress-induced liver disease that is closely related not only to genetic susceptibility but also to insulin resistance and highly linked with metabolic syndrome. In recent years, the prevalence of NAFLD has increased rapidly, paralleling the epidemic of type 2 diabetes mellitus and obesity leading to cardiovascular disease. It has been demonstrated that NAFLD is highly associated with atherosclerosis. With recently gained knowledge, it appears that NAFLD may induce insulin resistance, dyslipidemia, oxidative stress, inflammation, and fluctuation of adipokines associated with atherosclerosis. In this review, we aimed to summarize recent discoveries related to both NAFLD and atherosclerosis, and to identify possible mechanisms linking them.

Edaravone inhibits hypoxia-induced trophoblast-soluble Fms-like tyrosine kinase 1 expression: a possible therapeutic approach to preeclampsia

OBJECTIVE

To investigate the effects of edaravone, a potent free radical scavenger used clinically, on hypoxia-induced trophoblast-soluble Fms-like tyrosine kinase 1 (sFlt-1) expression.

METHODS

A trophoblast cell line (HRT-8/SVneo) impaired by cobalt chloride (CoCl2) was used as the cell model under hypoxic conditions. 3-[4, 5-dimethylthiazol-2-yl]-2, 5-diphenyl tetrazolium bromide (MTT) was used to measure the viability of cells exposed to CoCl2 and edaravone. The levels of intracellular reactive oxygen species (ROS) were analyzed by flow cytometry. mRNA expression of sFlt-1, vascular endothelial growth factor (VEGF), and placental growth factor (PlGF) in trophoblasts was measured by real-time polymerase chain reaction, and the secretion of sFlt-1, VEGF, and PlGF proteins was analyzed by enzyme-linked immunosorbent assays (ELISAs). A human umbilical vein endothelial cell (HUVEC) tube-formation assay was performed to identify the effects of CoCl2 and edaravone on vascular development.

RESULTS

CoCl2 treatment caused the loss of trophoblast viability, the formation of ROS, and sFlt-1 mRNA and protein expression in a dose-dependent manner. Pretreatment with edaravone significantly inhibited hypoxia-induced oxidative stress formation and sFlt-1 expression in trophoblasts. Neither PlGF nor VEGF mRNA or protein expression was increased by CoCl2. In the in vitro tube formation assay, edaravone showed a protective role in vascular development under hypoxic conditions.

CONCLUSION

This study demonstrated that hypoxia leading to increased sFlt-1 release in trophoblasts may contribute to the placental vascular formation abnormalities observed in preeclampsia and suggested that the free radical scavenger edaravone could be a candidate for the effective treatment of preeclampsia.

Novel molecular approaches for improving enzymatic and nonenzymatic detoxification of 4-hydroxynonenal: toward the discovery of a novel class of bioactive compounds

4-Hydroxy-trans-2-nonenal (HNE), an α,β-unsaturated aldehyde generated endogenously by the radical-mediated peroxidation of ω-6 polyunsaturated fatty acids, is a bioactive molecule acting in several physiopathological mechanisms and most of its activity is due to the covalent modification of biomolecules. Although at low and physiological levels HNE acts as an endogenous signaling molecule, a growing bulk of evidence indicates that at high and toxic concentrations, HNE is involved in the onset and propagation of several human diseases. To get more conclusive evidence of HNE as a pathogenetic factor, a pharmacological tool able to inhibit the HNE-induced cellular response is required. Such compound is currently not available, although several molecular strategies have so far been reported with the aim of inhibiting HNE formation or catalyzing its removal. Although most of these are not selective, such strategies have been found to induce several biological responses and would merit further investigation. In this review the various strategies are reported and discussed together with their limits and potentials.

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.

Sex differences in endothelial function of aged hypertriglyceridemic rats - effect of atorvastatin treatment

The aim of the study was to test the hypothesis that the effect of atorvastatin on endothelium-dependent relaxation of the superior mesenteric artery (SMA) may differ in male vs. female aged hypertriglyceridemic rats (HTGs). Experiments were performed on 11-month-old male and female Prague hereditary HTGs. Atorvastatin (ATO) was administered p.o. in the dose of 0.30 mg/100g/day. Controls received vehiculum. After two months of ATO administration blood pressure, serum triglycerides (TG) and total cholesterol (CHOL) were determined. Endothelial function of SMA was studied in vitro using evaluation of relaxant responses of precontracted SMA to acetylcholine. The serum TG of control male HTGs were found to be statistically higher than those of female controls, while CHOL and blood pressure did not share gender differences. Responses of SMA of female control HTGs were statistically decreased compared to their male counterparts. ATO treatment induced decrease in blood pressure and TG of both males and females, yet CHOL values were reduced only in females. The protective effect of ATO on SMA endothelial function was much more pronounced in females compared to males. We conclude that vascular endothelial dysfunction of aged HTG rats is more severe and more attenuated by ATO in females compared to males. The protective effect of ATO on vascular endothelial function does not seem to depend solely on its lipid lowering action.

Tautomers and polymorphs of pyrazolinone derivatives, generated from reactions of arylhydrazines, ArNHNH2, with 1,3-dicarbonyl compounds

From reactions of arylhydrazines with R2COCH2CONHPh or R2COCH2CO2Me, different tautomeric pyrazolinone forms, 1-aryl-3-R2-4,5-dihydro-1H-pyrazol-5-ones (IIa), 1-aryl-3-R2-1H-pyrazol-5-ols (IIb) and 2-aryl-5-R2-1,2-dihydro-3H-pyrazol-3-ones (IIc)], can be isolated. The crystal structures of monoclinic- and triclinic-3-phenyl-1-(3-nitrophenyl)-4,5-dihydro-1H-pyrazol-5-one (IIa forms), tautomeric 1-(4-methylphenyl)-3-phenyl-4,5-dihydro-1H-pyrazol-5-one (IIa form), and 1-(4-methylphenyl)-3-phenyl-1H-pyrazol-5-ol (IIb form), as well as1-(4-methoxyphenyl)-3-phenyl-1H-pyrazo-5-ol (IIb form) and 2-(4-methoxyphenyl)-5-methyl-1,2-dihydro-3H-pyrazol-3-one (IIc form) are reported.

The data suggest thatthe most electron withdrawing aryl group [3-nitrophenyl] generates IIa forms, while the most electron releasing aryl group [4-methoxyphenyl] generates IIb and IIc forms and that the aryl group with the intermediate electronic effect [4-methylphenyl] provides both IIa and IIb forms. This trend is supported by the reported isolations of 1-(4-chlorophenyl)-3-phenyl-4,5-dihydro-1H-pyrazol-5-one and 1-(2,4-nitrophenyl)-3-methyl-4,5-dihydro-1H-pyrazol-5-one [both IIa-forms] with electron-withdrawing chloro and nitro groups respectively and by the isolation of IIb and co-crystallised IIb/IIc forms from use of phenylhydrazine as the reactant.

Involvement of Kv1.5 protein in oxidative vascular endothelial cell injury

Endothelial injury related to oxidative stress is a key event in cardiovascular diseases, such as hypertension and atherosclerosis. The activation of the redox-sensitive Kv1.5 potassium channel mediates mitochondrial reactive oxygen species (ROS)-induced apoptosis in vascular smooth muscle cells and some cancer cells. Kv1.5 channel is therefore taken as a new potential therapeutic target for pulmonary hypertension and cancers. Although Kv1.5 is abundantly expressed in vascular endothelium, there is little knowledge of its role in endothelial injury related to oxidative stress. We found that DPO-1, a specific inhibitor of Kv1.5, attenuated H₂O₂-evoked endothelial cell apoptosis in an in vivo rat carotid arterial model. In human umbilical vein endothelial cells (HUVECs) and human pulmonary arterial endothelial cells (HPAECs), angiotensin II and oxLDL time- or concentration-dependently enhanced Kv1.5 protein expression in parallel with the production of intracellular ROS and endothelial cell injury. Moreover, siRNA-mediated knockdown of Kv1.5 attenuated, whereas adenovirus-mediated Kv1.5 cDNA overexpression enhanced oxLDL–induced cellular damage, NADPH oxidase and mitochondria-derived ROS production and restored the decrease in protein expression of mitochondria uncoupling protein 2 (UCP2). Collectively, these data suggest that Kv1.5 may play an important role in oxidative vascular endothelial injury.

Edaravone, a novel free radical scavenger, prevents steroid-induced osteonecrosis in rabbits

OBJECTIVE

To investigate the efficacy of edaravone, a novel free radical scavenger, on preventing steroid-induced osteonecrosis (ON) in a rabbit model.

METHODS

Thirty-six New Zealand white rabbits were divided into control (C; n = 6), steroid-administered (S; n = 15) and edaravone-administered groups (E; n = 15) after receiving an established protocol of steroid-induced ON. Before and after steroid administration, plasma levels of reduced glutathione (GSH) and lipid peroxidation (LPO) were measured for oxidative stress. Two weeks later bilateral proximal femurs were dissected for micro-CT-based micro-angiography, and the presence or absence of ON and intravascular thrombi were examined histopathologically. Immunohistochemical examination of oxidative injury in bone tissue was conducted using the anti-8-hydoxy-2'-deoxyguanosine and anti-malondialdehyde mAbs.

RESULTS

The incidence of ON in the E group (20%) was significantly lower than in the S group (73%). Three to five days after steroid administration, the plasma GSH level was significantly higher and LPO level was significantly lower in the E group than the S group. Compared with the S group, there were significantly more small-sized perfusion vessels and fewer large-sized dilated vessels in the E group. Thrombosis incidence was significantly lower in the E group than the S group. Intraosseous vessels and haematopoietic cells that sustained oxidative injury were significantly fewer in the E group than the S group.

CONCLUSION

Edaravone exerted beneficial effects on reducing incidence of steroid-induced ON by suppressing the accumulation of lipid peroxidative products and oxidative DNA damage in endothelial cells and haematopoietic cells.

The free radical scavenger S-PBN significantly prolongs DSG-mediated graft survival in experimental xenotransplantation

BACKGROUND

Nitrones such as 2-sulfo-phenyl-N-tert-butyl nitrone (S-PBN) are known to trap and stabilize free radicals and to reduce inflammation. Recently, S-PBN was shown to reduce infiltration of T lymphocytes and the expression of adhesion molecules on the endothelium in experimental traumatic brain injury. We hypothesized that S-PBN could reduce infiltration of T lymphocytes during cell-mediated xenograft rejection and thereby increase graft survival. The concordant mouse-to-rat heart transplantation model was used to test the hypothesis. In this model, grafts undergo acute humoral xenograft rejection (AHXR) almost invariably on day 3 and succumb to cell-mediated rejection on approximately day 8 if AHXR is inhibited by treatment with 15-deoxyspergualin (DSG).

MATERIAL AND METHODS

Hearts from Naval Medical Research Institute (NMRI) mice were transplanted to the neck vessels of Lewis rats. Recipients were treated with S-PBN (n=9), DSG (n=9), S-PBN and DSG in combination (n=10) or left untreated (n=9) for survival studies. S-PBN was given daily intraperitoneally at a dose of 150 mg/kg body weight (BW) on day -1 to 30, and DSG was given daily intraperitoneally at a dose of 10 mg/kg BW on day -1 to 4 and 5 mg/kg BW on day 5 to 21. Nine additional recipients were given S-PBN only on days -1 and 0 in combination with continuous DSG treatment. Grafts were monitored until they stopped beating. Additional recipients were treated with S-PBN (n=5), DSG (n=5), S-PBN and DSG in combination (n=6) or left untreated (n=5) for morphological, immunohistochemical and flow cytometry analyses on days 2 and 6 after transplantation.

RESULTS

S-PBN treatment in combination with DSG resulted in increased median graft survival compared to DSG treatment alone (14 vs. 7 days; P=0.019). Lower number of T lymphocytes on day 6 (P=0.019) was observed by ex vivo propagation and flow cytometry when combining S-PBN with DSG, whereas immunohistochemical analyses demonstrated a significant reduction in the number of infiltrated CD4+, but not TCR+, cells. S-PBN treatment alone had no impact on graft survival compared to untreated rats (3 vs. 3 days). No differences were seen in ICAM-1 and VCAM-1 expression or in morphology between the groups.

CONCLUSION

The combination of S-PBN and DSG treatment increases xenograft survival. The main effect of S-PBN appears to be in direct connection with the transplantation. Because of its low toxicity, S-PBN could become useful in combination with other immunosuppressants to reduce cell-mediated xenograft rejection.

Protective effects of 7-difluoromethyl-5,4'-dimethoxygenistein against human aorta endothelial injury caused by lysophosphatidyl choline

7-Difluoromethyl-5,4'-dimethoxygenistein (DFMG) is an active new derivative of genistein (GEN). It has shown effective protection in vascular endothelial injury. To further investigate its potential protective effects and its mechanism probably related to atherosclerosis, in present study, human aorta endothelial cells (HAECs) were chosen and treated with various concentrations of lysophosphatidyl choline (LPC) to establish an experimental model. Results showed that 10.0 μmol/l of LPC was optimal for inducing HAEC injury. DFMG pretreatment was able to prevent HAEC injury induced by LPC and restore cell viability in a concentration-dependent manner. The protective efficacy of DFMG (10.0 μmol/l) was significantly greater than that of GEN (10.0 μmol/l) and vitamin E (50.0 μmol/l). The mechanisms underlying the protective effects of DFMG are related to the activation of the antioxidant enzymes superoxide dismutase (SOD) and glutathione peroxidase and to the clearance of intracellular reactive oxygen species. DFMG inhibits the apoptosis of HAECs mediated by LPC involving the blockage of the mitochondrial apoptotic pathway.

Free radical scavenger, edaravone, reduces the lesion size of lacunar infarction in human brain ischemic stroke

Background

Although free radicals have been reported to play a role in the expansion of ischemic brain lesions, the effect of free radical scavengers is still under debate. In this study, the temporal profile of ischemic stroke lesion sizes was assessed for more than one year to evaluate the effect of edaravone which might reduce ischemic damage.

Methods

We sequentially enrolled acute ischemic stroke patients, who admitted between April 2003 and March 2004, into the edaravone(-) group (n = 83) and, who admitted between April 2004 and March 2005, into the edaravone(+) group (n = 93). Because, edaravone has been used as the standard treatment after April 2004 in our hospital. To assess the temporal profile of the stroke lesion size, the ratio of the area [T2-weighted magnetic resonance images (T2WI)/iffusion-weighted magnetic resonance images (DWI)] were calculated. Observations on T2WI were continued beyond one year, and observational times were classified into subacute (1-2 months after the onset), early chronic (3-6 month), late chronic (7-12 months) and old (≥13 months) stages. Neurological deficits were assessed by the National Institutes of Health Stroke Scale upon admission and at discharge and by the modified Rankin Scale at 1 year following stroke onset.

Results

Stroke lesion size was significantly attenuated in the edaravone(+) group compared with the edaravone(-) group in the period of early and late chronic observational stages. However, this reduction in lesion size was significant within a year and only for the small-vessel occlusion stroke patients treated with edaravone. Moreover, patients with small-vessel occlusion strokes that were treated with edaravone showed significant neurological improvement during their hospital stay, although there were no significant differences in outcome one year after the stroke.

Conclusion

Edaravone treatment reduced the volume of the infarct and improved neurological deficits during the subacute period, especially in the small-vessel occlusion strokes.

Analysis of isoflavones and flavonoids in human urine by UHPLC

A rapid, ultra high-performance liquid chromatographic (UHPLC) method has been developed and validated for simultaneous identification and analysis of the isoflavones genistein, daidzein, glycitin, puerarin, and biochanin A, and the flavonoids (±)-catechin, (−)-epicatechin, rutin, hesperidin, neohesperidin, quercitrin, and hesperetin in human urine. Urine samples were incubated with β-glucuronidase/sulfatase. UHPLC was performed with a Hypersil Gold (50 × 2.1 mm, 1.9 μm) analytical column. Elution was with a gradient prepared from aqueous trifluoroacetic acid (0.05%) and acetonitrile. UV detection was performed at 254 and 280 nm. The calibration curves were indicative of good linearity (r² ≥ 0.9992) in the range of interest for each analyte. LODs ranged between 15.4 and 107.0 ng mL⁻¹ and 3.9 and 20.4 ng mL⁻¹ for flavonoids and isoflavones, respectively. Intra-day and inter-day precision (C.V., %) was less than 3.9% and 3.8%, respectively, and accuracy was between 0.03% and 5.0%. Recovery was 70.35–96.58%. The method is very rapid, simple, and reliable, and suitable for pharmacokinetic analysis. It can be routinely used for simultaneous determination of these five isoflavones and seven flavonoids in human urine. The method can also be applied to studies after administration of pharmaceutical preparations containing isoflavones and flavonoids to humans.

Hydroethidine- and MitoSOX-derived red fluorescence is not a reliable indicator of intracellular superoxide formation: another inconvenient truth

Hydroethidine (HE; or dihydroethidium) is the most popular fluorogenic probe used for detecting intracellular superoxide radical anion. The reaction between superoxide and HE generates a highly specific red fluorescent product, 2-hydroxyethidium (2-OH-E(+)). In biological systems, another red fluorescent product, ethidium, is also formed, usually at a much higher concentration than 2-OH-E(+). In this article, we review the methods to selectively detect the superoxide-specific product (2-OH-E(+)) and the factors affecting its levels in cellular and biological systems. The most important conclusion of this review is that it is nearly impossible to assess the intracellular levels of the superoxide-specific product, 2-OH-E(+), using confocal microscopy or other fluorescence-based microscopic assays and that it is essential to measure by HPLC the intracellular HE and other oxidation products of HE, in addition to 2-OH-E(+), to fully understand the origin of red fluorescence. The chemical reactivity of mitochondria-targeted hydroethidine (Mito-HE, MitoSOX red) with superoxide is similar to the reactivity of HE with superoxide, and therefore, all of the limitations attributed to the HE assay are applicable to Mito-HE (or MitoSOX) as well.

Edaravone inhibits protein carbonylation by a direct carbonyl-scavenging mechanism: focus on reactivity, selectivity, and reaction mechanisms

The aim of this study was to evaluate the ability of the well-known radical scavenging compound edaravone (EDA) to entrap and detoxify reactive carbonyl species (RCS) derived from lipid peroxidation [4-hydroxy-trans-2-nonenal (HNE), acrolein and glyoxal], as well as its ability to prevent RCS-induced protein carbonylation, by using hemoglobin (Hb) modified by HNE as an in vitro model. Through a combined HPLC and high-resolution mass spectrometric approach, we confirmed the ability of EDA to scavenge precursors for either advanced glycation or lipoxidation end products (EAGLEs), such as glyoxal, and demonstrated for the first time that EDA is also a potent quencher of alpha,beta-unsaturated aldehydes (providing mass spectral characterization of the adducts), being significantly more active than a series of well-known RCS sequestering agents. Direct infusion analysis of the intact protein and nano LC-ESI-MS/MS analysis of the tryptic digest, carried out on an LTQ-Orbitrap hybrid mass spectrometer, were used to study the modifications occurring on Hb after exposure to increasing HNE concentrations, providing evidence for Cys93 (Hb beta-chain) involvement in covalent attachment, and to demonstrate the ability of EDA dose-dependently to inhibit Hb carbonylation. Computational studies allowed us to elucidate the mechanism of EDA-RCS interaction and to explain the preferential site of HNE adduction to Hb. The same combined approach indicated that EDA is not a selective RCS scavenger, being able to react also with nontoxic, physiologically relevant aldehydes, such as pyridoxal.

Reactive oxygen species modulate growth of cerebral aneurysms: a study using the free radical scavenger edaravone and p47phox(-/-) mice

Cerebral aneurysm (CA) is a relatively common disease and can cause a catastrophic subarachnoid hemorrhage with a high mortality and morbidity rate. Despite its clinical and social importance, the detailed mechanism of CA formation remains to be elucidated, resulting in the absence of effective medical treatment against CAs. Recent studies revealed that chronic inflammation in arterial walls by hemodynamic force is implicated in CA formation. Reactive oxygen species (ROS) are a major mediator of inflammation and actively participate in the pathogenesis of various vascular diseases. In the present study, we first assessed the expression of ROS-producing and -eliminating genes in CA walls by immunohistochemistry and RT-PCR analysis. The ROS-producing gene, p47phox, was upregulated in infiltrating macrophages and medial smooth muscle cells in arterial walls. Upregulated ROS-producing genes and suppressed ROS-eliminating genes suggested that ROS overproduction occurred in aneurysmal walls. In situ superoxide imaging by dihydroethidium, which showed ROS overproduction in aneurysmal walls, confirmed this hypothesis. Edaravone, a powerful free radical scavenger, effectively inhibited CA formation by suppressing inflammation-related gene expression in aneurysmal walls. Furthermore, CA formation was markedly inhibited by p47phox deletion in mice and was accompanied by decreased inflammation in aneurysmal walls. These data suggested the active participation of ROS and p47phox in CA formation and the therapeutic potential of an ROS-eliminating agent against CA formation.