Antioxidant MCI-186 inhibits mitochondrial permeability transition pore and upregulates Bcl-2 expression

Mitochondrial Permeability Transition in Stem Cells, Development, and Disease

The mitochondrial permeability transition (mPT) is a process that permits rapid exchange of small molecules across the inner mitochondrial membrane (IMM) and thus plays a vital role in mitochondrial function and cellular signaling. Formation of the pore that mediates this flux is well-documented in injury and disease but its regulation has also emerged as critical to the fate of stem cells during embryonic development. The precise molecular composition of the mPTP has been enigmatic, with far more genetic studies eliminating molecular candidates than confirming them. Rigorous studies in the recent decade have implicated central involvement of the F₁F_o ATP synthase, or complex V of the electron transport chain, and continue to confirm a regulatory role for Cyclophilin D (CypD), encoded by Ppif, in modulating the sensitivity of the pore to opening. A host of endogenous molecules have been shown to trigger flux characteristic of mPT, including positive regulators such as calcium ions, reactive oxygen species, inorganic phosphate, and fatty acids. Conductance of the pore has been described as low or high, and reversibility of pore opening appears to correspond with the relative abundance of negative regulators of mPT such as adenine nucleotides, hydrogen ion, and divalent cations that compete for calcium-binding sites in the mPTP. Current models suggest that distinct pores could be responsible for differing reversibility and conductance depending upon cellular context. Indeed, irreversible propagation of mPT inevitably leads to collapse of transmembrane potential, arrest of ATP synthesis, mitochondrial swelling, and cell death. Future studies should clarify ambiguities in mPTP structure and reveal new roles for mPT in dictating specialized cellular functions beyond cell survival that are tied to mitochondrial fitness including stem cell self-renewal and fate. The focus of this review is to describe contemporary models of the mPTP and highlight how pore activity impacts stem cells and development.

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.

Effects of the Edaravone, a Drug Approved for the Treatment of Amyotrophic Lateral Sclerosis, on Mitochondrial Function and Neuroprotection

Edaravone, the first known free radical scavenger, has demonstrated cellular protective properties in animals and humans. Owing to its antioxidant activity, edaravone modulates oxidative damage in various diseases, especially neurodegenerative diseases. In 2015, edaravone was approved in Japan to treat amyotrophic lateral sclerosis. The distinguishing pathogenic features of neurodegenerative diseases include high reactive oxygen species levels and mitochondrial dysfunction. However, the correlation between mitochondria and edaravone has not been elucidated. This review highlights recent studies on novel therapeutic perspectives of edaravone in terms of its effect on oxidative stress and mitochondrial function.

Indazole and its Derivatives in Cardiovascular Diseases: Overview, Current Scenario, and Future Perspectives

Indazoles are a class of heterocyclic compounds with a bicyclic ring structure composed of a pyrazole ring and a benzene ring. Indazole-containing compounds with various functional groups have important pharmacological activities and can be used as structural motifs in designing novel drug molecules. Some of the indazole-containing molecules are approved by FDA and are already in the market. However, very few drugs with indazole rings have been developed against cardiovascular diseases. This review aims to summarize the structural and pharmacological functions of indazole derivatives which have shown efficacy against cardiovascular pathologies in experimental settings.

Association of Prolonged Disease Duration and TG/HDL-C Ratio in Accelerating Atherosclerosis in Patients with Takayasu's Arteritis

Background and aim: Takayasu's arteritis (TA) is a chronic inflammation that frequently involves the aorta and its major branches. It has been known that atherosclerosis can occur in some TA patients. Objectives: This study aimed to identify the risk factors associated with the development of atherosclerosis in TA. Methods: This retrospective study enrolled a total of 101 TA patients. All patients were divided into two groups according to the absence or presence of atherosclerosis. Baseline demographic features and clinical characteristics were compared between two groups. A logistic model was applied to determine the risk factors associated with the development of atherosclerosis. Results: Our data suggested that the disease duration of patients in the atherosclerosis group was significantly longer than that of patients in the non-atherosclerosis group [96(18.00, 180.00) versus 48.00(12.00, 111.00) months] (P = .015). In addition, the average age of patients with atherosclerosis was significantly older compared to patients without atherosclerosis [44.00(38.00, 48.00)versus 28.50(24.00，37.00)years] (P < .001). Logistic regression analysis showed that the risk of developing atherosclerosis increased by 9.2% per 1 year increase in the disease duration (P = .005, OR 1.092, 95%CI: 1.027-1.162). Patients with TG/HDL-C ratio more than 0.8875 were associated with a 5.861fold increase of risk developing atherosclerosis (P < .001, OR 5.861, 95%CI: 2.299-14.939). Conclusion: Our study indicated that prolonged disease duration and elevated TG/HDL-C ratio are associated with the development of atherosclerosis in TA patients.

Role of Oxidative Stress in Reperfusion following Myocardial Ischemia and Its Treatments

Myocardial ischemia is a disease with high morbidity and mortality, for which reperfusion is currently the standard intervention. However, the reperfusion may lead to further myocardial damage, known as myocardial ischemia/reperfusion injury (MI/RI). Oxidative stress is one of the most important pathological mechanisms in reperfusion injury, which causes apoptosis, autophagy, inflammation, and some other damage in cardiomyocytes through multiple pathways, thus causing irreversible cardiomyocyte damage and cardiac dysfunction. This article reviews the pathological mechanisms of oxidative stress involved in reperfusion injury and the interventions for different pathways and targets, so as to form systematic treatments for oxidative stress-induced myocardial reperfusion injury and make up for the lack of monotherapy.

Edaravone attenuates H2O2 or glutamate-induced toxicity in hippocampal neurons and improves AlCl3/D-galactose induced cognitive impairment in mice

Edaravone (Eda) is a free radical scavenger used in clinical trials for the treatment of ischemic stroke and amyotrophic lateral sclerosis. However, how Eda exerts its neuroprotective effects remains to be elucidated. We investigated the neuroprotective effects of Eda in cultured hippocampal neurons and in a mouse model of AlCl₃/D-galactose-induced cognitive impairment. Eda protected hippocampal neurons by eliminating H₂O₂ or glutamate-induced toxicity, leading to decreased cell viability and neurite shortening. Consistently, Eda restored impaired levels of BDNF, FGF2 and their associated signaling axes (including TrkB, p-Akt and Bcl-2) to attenuate neuronal death. In a mouse model of chemically-induced cognitive impairment, Eda restored the levels of BDNF, FGF2 and TrkB/Akt signaling axis to attenuate neuronal apoptosis, thereby ameliorating cognitive impairment. Meanwhile, the pro-inflammation was eliminated due to the restoration of pro-inflammatory factors such as TNF-α, IL-6, IL-1β, and NOS2. In summary, Eda is an effective drug for protecting neurons from neurotoxic injury. BDNF, FGF2, and their regulated pathways may be potential therapeutic targets for neuroprotection.

Targeted antioxidants as therapeutics for treatment of pneumonia in the elderly

Community acquired pneumonia is a leading cause of mortality in the United States. Along with predisposing comorbid health status, age is an independent risk factor for determining the outcome of pneumonia. Research over the last few decades has contributed to better understanding the underlying immunodysregulation and imbalanced redox homeostasis tied to this aged population group that increases susceptibility to a wide range of pathologies. Major approaches include targeting oxidative stress by reducing ROS generation at its main sources of production which includes the mitochondrion. Mitochondria-targeted antioxidants have a number of molecular strategies that include targeting the biophysical properties of mitochondria, mitochondrial localization of catalytic enzymes, and mitigating mitochondrial membrane potential. Results of several antioxidant studies both in vitro and in vivo have demonstrated promising potential as a therapeutic in the treatment of pneumonia in the elderly. More human studies will need to be conducted to evaluate its efficacy in this clinical setting.

Mitochondrial Permeability Transition: A Molecular Lesion with Multiple Drug Targets

Mitochondrial permeability transition, as the consequence of opening of a mitochondrial permeability transition pore (mPTP), is a cellular catastrophe. Initiating bioenergetic collapse and cell death, it has been implicated in the pathophysiology of major human diseases, including neuromuscular diseases of childhood, ischaemia-reperfusion injury, and age-related neurodegenerative disease. Opening of the mPTP represents a major therapeutic target, as it can be mitigated by a number of compounds. However, clinical studies have so far been disappointing. We therefore address the prospects and challenges faced in translating in vitro findings to clinical benefit. We review the role of mPTP opening in disease, discuss recent findings defining the putative structure of the mPTP, and explore strategies to identify novel, clinically useful mPTP inhibitors, highlighting key considerations in the drug discovery process.

Edaravone and cyclosporine A as neuroprotective agents for acute ischemic stroke

It is well known that acute ischemic stroke (AIS) and subsequent reperfusion produce lethal levels of reactive oxygen species (ROS) in neuronal cells, which are generated in mitochondria. Mitochondrial ROS production is a self-amplifying process, termed "ROS-induced ROS release". Furthermore, the mitochondrial permeability transition pore (MPTP) is deeply involved in this process, and its opening could cause cell death. Edaravone, a free radical scavenger, is the only neuroprotective agent for AIS used in Japan. It captures and reduces excessive ROS, preventing brain damage. Cyclosporine A (CsA), an immunosuppressive agent, is a potential neuroprotective agent for AIS. It has been investigated that CsA prevents cellular death by suppressing MPTP opening. In this report, we will outline the actions of edaravone and CsA as neuroprotective agents in AIS, focusing on their relationship with ROS and MPTP.

Study of respiratory chain dysfunction in heart disease

The relentlessly beating heart has the greatest oxygen consumption of any organ in the body at rest reflecting its huge metabolic turnover and energetic demands. The vast majority of its energy is produced and cycled in form of ATP which stems mainly from oxidative phosphorylation occurring at the respiratory chain in the mitochondria. A part from energy production, the respiratory chain is also the main source of reactive oxygen species and plays a pivotal role in the regulation of oxidative stress. Dysfunction of the respiratory chain is therefore found in most common heart conditions. The pathophysiology of mitochondrial respiratory chain dysfunction in hereditary cardiac mitochondrial disease, the aging heart, in LV hypertrophy and heart failure, and in ischaemia-reperfusion injury is reviewed. We introduce the practicing clinician to the complex physiology of the respiratory chain, highlight its impact on common cardiac disorders and review translational pharmacological and non-pharmacological treatment strategies.

Mitochondrial involvement in myocyte death and heart failure

As the heart is an energy-demanding organ, impaired cardiac energy metabolism and mitochondrial function have been inexorably linked to cardiac dysfunction. There is a growing recognition that mitochondrial dysfunction contributes to impaired myocardial energetics and increased oxidative stress in cardiomyopathies, cardiac ischemic damage and heart failure (HF), and mitochondrial permeability transition pore opening has been reported a critical trigger of myocyte death and myocardial remodeling. It is well established that mitochondria play pivotal roles in intracellular signaling in both cell death as well as in cardioprotective pathways. Moreover, recent studies have shown that defects in mitochondrial dynamics affecting biogenesis and turnover are linked to cardiac senescence and HF. Accordingly, there has been an increasing interest in targeting mitochondria for HF therapy. This article reviews the background and recent evidence of mitochondrial involvement in several types of cell death (apoptosis, necrosis and autophagy) occurring in HF. In addition, potential strategies for targeting mitochondria are examined, and their utility in HF therapy considered.

The antioxidant edaravone prevents cardiac dysfunction by suppressing oxidative stress in type 1 diabetic rats and in high-glucose-induced injured H9c2 cardiomyoblasts

Edaravone, a radical scavenger, has been recognized as a potential protective agent for cardiovascular diseases. However, little is known about the effect of edaravone in cardiac complications associated with diabetes. Here, we have demonstrated that edaravone prevents cardiac dysfunction and apoptosis in the streptozotocin-induced type 1 diabetic rat heart. Mechanistic studies revealed that edaravone treatment improved cardiac function and restored superoxide dismutase levels. In addition, treatment of diabetic animals by edaravone increased protein expressions of sirtuin-1 (SIRT-1), peroxisome proliferator activated receptor γ coactivator α (PGC-1α), nuclear factor like-2 (NRF-2), and B cell lymphoma 2 (Bcl-2), and reduced protein expressions of Bax and Caspase-3 compared to the control group. High glucose incubation resulted in the production of reactive oxygen species (ROS) and cell death. Treatment of high-glucose-incubated H9c2 cells by edaravone reduced ROS production and cell death. In addition, the treatment of high-glucose-incubated H9c2 cells by edaravone increased the activity of antioxidative stress by increasing SIRT-1, PGC-1α, and NRF-2, and this treatment also reduced apoptosis by increasing Bcl-2 expression and reducing Bax and Caspase-3 expressions. Knockdown SIRT-1 with small interferer RNA abolished the effects of edaravone. Overall, our data demonstrated that edaravone may be an effective agent against the development of diabetic cardiomyopathy.

Rescue of Heart Failure by Mitochondrial Recovery

Heart failure (HF) is a multifactorial disease brought about by numerous, and oftentimes complex, etiological mechanisms. Although well studied, HF continues to affect millions of people worldwide and current treatments can only prevent further progression of HF. Mitochondria undoubtedly play an important role in the progression of HF, and numerous studies have highlighted mitochondrial components that contribute to HF. This review presents an overview of the role of mitochondrial biogenesis, mitochondrial oxidative stress, and mitochondrial permeability transition pore in HF, discusses ongoing studies that attempt to address the disease through mitochondrial targeting, and provides an insight on how these studies can affect future research on HF treatment.

NADPH Oxidase/ROS-Dependent VCAM-1 Induction on TNF-α-Challenged Human Cardiac Fibroblasts Enhances Monocyte Adhesion

The inflammation-dependent adhesion molecule expressions are characterized in cardiovascular diseases and myocardial tissue infiltrations. Several pro-inflammatory cytokines are elevated in the acute myocardial injury and infarction. Tumor necrosis factor-α (TNF-α), a pro-inflammatory cytokine, is raised in the injury tissues and inflammatory regions and involved in the pathogenesis of cardiac injury, inflammation, and apoptosis. In fibroblasts, TNF-α-triggered expression of vascular cell adhesion molecule (VCAM)-1 aggravated the heart inflammation. However, the mechanisms underlying TNF-α-mediated VCAM-1 expression in cardiac fibroblasts remain unclear. Here, the primary cultured human cardiac fibroblasts (HCFs) were used to investigate the effects of TNF-α on VCAM-1 expression. The molecular evidence, including protein, mRNA, and promoter analyses, indicated that TNF-α-induced VCAM-1 gene expression is mediated through the TNFR-dependent manner. Activation of TNF-α/TNFR system triggered PKCα-dependent NADPH oxidase (Nox)/reactive oxygen species (ROS) signal linking to MAPK cascades, and then led to activation of the transcription factor, AP-1. Moreover, the results of mRNA and promoter assay demonstrated that c-Jun/AP-1 phosphorylated by TNF-α turns on VCAM-1 gene expression. Subsequently, up-regulated VCAM-1 on the cell surface of TNF-α-challenged HCFs increased the number of monocytes adhering to these cells. These results indicated that in HCFs, activation of AP-1 by PKCα-dependent Nox/ROS/MAPKs cascades is required for TNF-α-induced VCAM-1 expression. To clarify the mechanisms of TNF-α-induced VCAM-1 expression in HCFs may provide therapeutic strategies for heart injury and inflammatory diseases.

Statins Trigger Mitochondrial Reactive Oxygen Species-Induced Apoptosis in Glycolytic Skeletal Muscle

AIMS

Although statins are the most widely used cholesterol-lowering agents, they are associated with a variety of muscle complaints. The goal of this study was to characterize the effects of statins on the mitochondrial apoptosis pathway induced by mitochondrial oxidative stress in skeletal muscle using human muscle biopsies as well as in vivo and in vitro models.

RESULTS

Statins increased mitochondrial H2O2 production, the Bax/Bcl-2 ratio, and TUNEL staining in deltoid biopsies of patients with statin-associated myopathy. Furthermore, atorvastatin treatment for 2 weeks at 10 mg/kg/day in rats increased H2O2 accumulation and mRNA levels and immunostaining of the Bax/Bcl-2 ratio, as well as TUNEL staining and caspase 3 cleavage in glycolytic (plantaris) skeletal muscle, but not in oxidative (soleus) skeletal muscle, which has a high antioxidative capacity. Atorvastatin also decreased the GSH/GSSG ratio, but only in glycolytic skeletal muscle. Cotreatment with the antioxidant, quercetin, at 25 mg/kg/day abolished these effects in plantaris. An in vitro study with L6 myoblasts directly demonstrated the link between mitochondrial oxidative stress following atorvastatin exposure and activation of the mitochondrial apoptosis signaling pathway.

INNOVATION

Treatment with atorvastatin is associated with mitochondrial oxidative stress, which activates apoptosis and contributes to myopathy. Glycolytic muscles are more sensitive to atorvastatin than oxidative muscles, which may be due to the higher antioxidative capacity in oxidative muscles.

CONCLUSION

There is a link between statin-induced mitochondrial oxidative stress and activation of the mitochondrial apoptosis signaling pathway in glycolytic skeletal muscle, which may be associated with statin-associated myopathy.

Protective effect of Edaravone against hypoxia-induced cytotoxicity in osteoblasts MC3T3-E1 cells

Edaravone is a newly developed clinical medicine for the treatment of acute cerebral infarction. Reduced blood supply to bones (hypoxia) has been involved in the pathological development of osteoporosis. In this study, we investigated the effect of Edaravone and its latent mechanism on hypoxia-induced cell toxicity in MC3T3-E1 cells. Cell viability was determined by the 3-(4,5-dimethyl-thiazol-2yl)-2,5-diphenyl tetrazolium bromide (MTT) assay. Intracellular reactive oxygen species (ROS) and nitric oxide (NO) were determined by the fluorescence dyes 2',7'-dichlorofluorescein diacetate (DCFH-DA) and 4-amino-5-methylamino-2',7'-difluorofluorescein diacetate (DAF-FM DA), respectively. mRNA and proteins were determined by real-time polymerase chain reaction and Western blot analysis, respectively. Edaravone significantly restored the hypoxia-induced reduction of MC3T3-E1 cell viability and inhibited lactate dehydrogenase release. In addition, we found that Edaravone inhibits the generation of ROS and NO. Hoechst staining results indicated that the nuclear condensation characteristic of apoptosis was increased in MC3T3-E1 cells after hypoxia exposure, which was significantly suppressed by Edaravone treatment. Mechanistically, we found that Edaravone markedly reduced the expression of cleaved caspase-3 and blunted the release of cytochrome c. These findings strongly suggested that Edaravone suppresses hypoxia-induced cytotoxicity in MC3T3-E1 cells. The pleiotropic effects of Edaravone on hypoxia exposure in osteoblasts suggest potential antiosteoporosis mechanisms of Edaravone.

Combination of total Astragalus extract and total Panax notoginseng saponins strengthened the protective effects on brain damage through improving energy metabolism and inhibiting apoptosis after cerebral ischemia-reperfusion in mice

OBJECTIVE

To explore the effects and molecular mechanisms of the combination between total Astragalus extract (TAE) and total Panax notoginseng saponins (TPNS) against cerebral ischemia-reperfusion injury.

METHODS

C57BL/6 mice were randomly divided into sham-operated group, model group, TAE (110 mg/kg) group, TPNS (115 mg/kg) group, TAE-TPNS combination group and Edaravone (4 mg/kg) group, treated for 4 days, then, cerebral ischemia-reperfusion injury was established by bilateral common carotid artery (CCA) ligation for 20 min followed by reperfusion for 1 and 24 h.

RESULTS

TPNS could increase adenosine triphosphate (ATP) level, TAE and TAE-TPNS combination increased ATP, adenosine diphosphate (ADP) contents and Na⁺-K⁺-ATPase activity, and the effects of TAE-TPNS combination were stronger than those of TAE or TPNS alone after reperfusion for 1 h. After reperfusion for 24 h, TAE, TPNS and TAE-TPNS combination significantly increased neurocyte survival rate and decreased the apoptosis rate as well as down-regulated the expression of phosphorylated c-June N-terminal kinase1/2 (p-JNK1/2), cytochrome C (Cyt C), cysteine aspartic acid-specific protease (Caspase)-9 and Caspase-3. Furthermore, the effects in TAE-TPNS combination were better than those in TAE or TPNS alone.

CONCLUSION

The combination of TAE 110 mg/kg and TPNS 115 mg/kg could strengthen protective effects on cerebral ischemia injury, the mechanism underlying might be related to improving jointly the early energy metabolism, and relieving the delayed apoptosis via inhibiting the mitochondrial apoptosis pathway of JNK signal transduction.

The breathing heart - mitochondrial respiratory chain dysfunction in cardiac disease

The relentlessly beating heart has the greatest oxygen consumption of any organ in the body at rest reflecting its huge metabolic turnover and energetic demands. The vast majority of its energy is produced and cycled in form of ATP which stems mainly from oxidative phosphorylation occurring at the respiratory chain in the mitochondria. Apart from energy production, the respiratory chain is also the main source of reactive oxygen species and plays a pivotal role in the regulation of oxidative stress. Dysfunction of the respiratory chain is therefore found in most common heart conditions. The pathophysiology of mitochondrial respiratory chain dysfunction in hereditary cardiac mitochondrial disease, the ageing heart, in LV hypertrophy and heart failure, and in ischaemia-reperfusion injury is reviewed. We introduce the practising clinician to the complex physiology of the respiratory chain, highlight its impact on common cardiac disorders and review translational pharmacological and non-pharmacological treatment strategies.

[Effects of the combination of active component extracts from Astragalus membranaceus and Panax notoginseng on apoptosis, reactive oxygen species and mitochondrial membrane potential of PC12 cells with oxidative injury]

OBJECTIVE

To explore the effects and mechanisms of combining astragaloside IV (the effective component of Astragalus membranaceus) with notoginsenoside R1, ginsenoside Rb1 and ginsenoside Rg1 (the effective components of Panax notoginseng) against oxidative injury in PC12 cells induced by cobalt chloride (CoCl₂).

METHODS

CoCl₂ was used to stimulate PC12 cells to induce injury after transdifferentiation with nerve growth factor. Then the PC12 cells were divided into 10 groups and cultured with corresponding drugs. After culture, apoptotic cells were tested by using Hocchst 33258 fluorescent staining, the level of mitochondrial membrane potential (MMP) was analyzed by rhodamine 123 fluorescent staining and the content of reactive oxygen species (ROS) in PC12 cell was measured by dichlorofluorescin diacetate fluorescent staining.

RESULTS

CoCl₂ induced apoptosis along with the obvious decrease of MMP as well as overproduction of ROS in PC12 cells. Astragaloside IV, ginsenosides Rg1, ginsenosides Rb1 and notoginsenoside R1 had inhibition effects in different degree on PC12 cell apoptosis induced by CoCl₂, reduced the overproduction of ROS and the decrease of MMP. The effects of the combination were better than those of active component alone.

CONCLUSION

Active components extracted from Astragalus and Panax notoginseng can inhibit PC12 cell apoptosis induced by oxidative injury, furthermore, the effects were enhanced by combination of these components, which may be associated with jointly antagonizing the generation of ROS and raising MMP.

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.

Edaravone prevents neurotoxicity of mutant L166P DJ-1 in Parkinson's disease

Parkinson's disease (PD), which is estimated to affect approximately 1 % of the population over the age of 65, is the second most common neurodegenerative disorder after Alzheimer's disease. It was reported that pathogenic mutations in DJ-1 lead to autosomal recessive early-onset familial Parkinsonism. The L166P mutant of DJ-1 is the most commonly studied loss-of-function mutation in early onset familial PD, but the underlying mechanisms are still unknown. Edaravone is a powerful free radical scavenger used in clinical treatment for cerebral ischemic stroke. In the present study, we investigated the effects of edaravone on the neurotoxicity in PD-induced isoforms of DJ-1 containing the mutation L166P. Our results indicated that edaravone was able to significantly attenuate oxidative stress and improve mitochondrial function. Furthermore, edaravone was found to reduce apoptosis in Neuro2a cells through modulation of mitochondria-dependent apoptosis pathways. Interestingly, our result also demonstrated that edaravone was able to up-regulate VMAT2 expression in N2a cells in a dose-dependent manner. Our findings enhance the understanding of the neuro-protective effects of edaravone in cell models and suggest that edaravone offers significant protection in a PD-related in vitro model.

Skeletal muscle post-conditioning by diazoxide, anti-oxidative and anti-apoptotic mechanisms

Pretreatment with diazoxide, K(ATP) channel opener, increases tissue tolerance against ischemia reperfusion (IR) injury. In clinical settings pretreatment is rarely an option therefore we evaluated the effect of post-ischemic treatment with diazoxide on skeletal muscle IR injury. Rats were treated with either saline, diazoxide (K(ATP) opener; 40 mg/kg) or 5-hydroxydecanoate (5-HD; mitochondrial K(ATP) inhibitor; 40 mg/kg) after skeletal muscle ischemia (3 h) and reperfusion (6, 24 or 48 h). Tissue contents of malondialdehyde (MDA), superoxide dismutase (SOD) and catalase (CAT) activities, Bax and Bcl-2 protein expression and muscle histology were determined. Apoptosis was examined (24 and 48 h) after ischemia. IR induced severe histological damage, increased MDA content and Bax expression (24 and 48 h; p < 0.01) and decreased CAT and SOD activities (6 and 24 h, p < 0.01 and 48 h, p < 0.05), with no significant effect on Bcl-2 expression. Diazoxide reversed IR effects on MDA (6 and 24 h; p < 0.05), SOD (6 and 24 h; p < 0.01) and CAT (6 and 48 h, p < 0.05 and 24 h p < 0.01) and tissue damage. Diazoxide also decreased Bax (24 and 48 h; p < 0.05) and increased Bcl-2 protein expression (24 and 48 h; p < 0.01). Post-ischemic treatment with 5-HD had no significant effect on IR injury. Number of apoptotic nuclei in IR and 5-HD treated groups significantly increased (p < 0.001) while diazoxide decreased apoptosis (p < 0.01). The results suggested that post-ischemic treatment with diazoxide decrease oxidative stress in acute phase which modulates expression of apoptotic proteins in the late phase of reperfusion injury. Involvement of KATP channels in this effect require further evaluations.

Astragalus extract alleviates nerve injury after cerebral ischemia by improving energy metabolism and inhibiting apoptosis

This aim of this study was to explore the effects and molecular mechanisms of Astragalus extract against cerebral ischemia injury through the energy metabolism and apoptosis pathways of c‑Jun N-terminal kinase (JNK) signal transduction. After the bilateral common carotid artery of C57BL/6 mice was occluded for 20 min followed by 1-h reperfusion, the ATP content, total adenine nucleotides (TAN), energy charge (EC), and sodium potassium ATPase (Na(+)-K(+)‑ATPase) activity were decreased markedly in brain tissues. Astragalus extract markedly increased the ATP and ADP levels, EC value, and Na(+)-K(+)-ATPase activity. Twenty-four and 48 h after reperfusion, the neurocyte survival rate decreased and apoptosis rate increased, while the expression of phosphorylated JNK1/2, cytochrome c (Cyt C), and cysteine aspartic acid-specific protease (caspase)-9 and -3 were significantly enhanced in brain tissues. Astragalus extract significantly increased neurocyte survival and decreased the apoptosis rate as well as down-regulated the expression of p-JNK1/2, Cyt C, caspase-9, and caspase-3. These results suggest that Astragalus extract has neuroprotective effects against nerve injury after cerebral ischemia-reperfusion, and the underlying mechanism may be associated with improved cellular energy metabolism, inhibition of JNK signal transduction pathway activation, and then suppression of the mitochondrial apoptosis pathway.

Mitochondrial therapeutics for cardioprotection

Mitochondria represent approximately one-third of the mass of the heart and play a critical role in maintaining cellular function-however, they are also a potent source of free radicals and pro-apoptotic factors. As such, maintaining mitochondrial homeostasis is essential to cell survival. As the dominant source of ATP, continuous quality control is mandatory to ensure their ongoing optimal function. Mitochondrial quality control is accomplished by the dynamic interplay of fusion, fission, autophagy, and mitochondrial biogenesis. This review examines these processes in the heart and considers their role in the context of ischemia-reperfusion injury. Interventions that modulate mitochondrial turnover, including pharmacologic agents, exercise, and caloric restriction are discussed as a means to improve mitochondrial quality control, ameliorate cardiovascular dysfunction, and enhance longevity.

Beyond free radical scavenging: Beneficial effects of edaravone (Radicut) in various diseases (Review)

Free radicals play an important role in the pathogenesis of a variety of diseases; thus, they are an attractive target for therapeutic intervention in these diseases. Compounds capable of scavenging free radicals have been developed for this purpose and some, developed for the treatment of cerebral ischemic stroke, have progressed to clinical trials. One such scavenger, edaravone, is used to treat patients within 24 h of stroke. Edaravone, which can diffuse into many disease-affected organs, also shows protective effects in the heart, lung, intestine, liver, pancreas, kidney, bladder and testis. As well as scavenging free radicals, edaravone has anti-apoptotic, anti-necrotic and anti-cytokine effects in various diseases. Here, we critically review the literature on its clinical efficacy and examine whether edaravone should be considered a candidate for worldwide development, focusing on its effects on diseases other than cerebral infarction. Edaravone has been safely used as a free radical scavenger for more than 10 years; we propose that edaravone may offer a novel treatment option for several diseases.

Results of and further prevention of hypoxic fetal brain damage by inhibition of xanthine oxidase enzyme with allopurinol

Several experimental models on adult and newborn animals showed that in cerebral hypoxic-ischemic conditions similar to clinical states the main source of the excessive production of free oxygen radicals is the highly activated xanthine oxidase (XO) enzyme reaction. Long before this data were available, it became known that the main role of allopurinol (AP) is the inhibition of XO. On the basis of these results, many therapeutic trials with AP were performed both in experimental and clinical studies of ischemia and reperfusion. However, it has been shown that only preventive administration of AP has favorable effects. The explanation for the poor results of AP treatment in human fetal brain damage (FBD) cases is that the drug was applied postnatally. The clinical studies performed in healthy laboring mothers whose deliveries were complicated with FBD showed that placental transfer after prenatal administration of AP may be effective in protecting newborns at increased risk of hypoxic-ischemic cerebral damage. Further controlled trials are required to determine if the prophylactic use of the drug might prevent hypoxic-ischemic injuries when the drug is administered immediately prior to impending fetal hypoxia, or even in deliveries at risk of developing hypoxia.

Edaravone guards dopamine neurons in a rotenone model for Parkinson's disease

3-methyl-1-phenyl-2-pyrazolin-5-one (edaravone), an effective free radical scavenger, provides neuroprotection in stroke models and patients. In this study, we investigated its neuroprotective effects in a chronic rotenone rat model for Parkinson's disease. Here we showed that a five-week treatment with edaravone abolished rotenone's activity to induce catalepsy, damage mitochondria and degenerate dopamine neurons in the midbrain of rotenone-treated rats. This abolishment was attributable at least partly to edaravone's inhibition of rotenone-induced reactive oxygen species production or apoptotic promoter Bax expression and its up-regulation of the vesicular monoamine transporter 2 (VMAT2) expression. Collectively, edaravone may provide novel clinical therapeutics for PD.

Edaravone, an ROS scavenger, ameliorates photoreceptor cell death after experimental retinal detachment

PURPOSE

To investigate whether edaravone (3-methyl-1-phenyl-2-pyrazolin-5-one), a free radical scavenger, would be neuroprotective against photoreceptor cell death in a rat model of retinal detachment (RD).

METHODS

RD was induced in adult Brown Norway rats by subretinal injection of sodium hyaluronate. Edaravone (3, 5, or 10 mg/kg) or physiologic saline was administered intraperitoneally once a day until death on day 3 or 5. Oxidative stress in the retina was assessed by 4-hydroxynonenal staining or ELISA for protein carbonyl content. Photoreceptor death was assessed by TUNEL and measurement of the outer nuclear layer thickness. Western blot analysis and caspase activity assays were performed. Inflammatory cytokine secretion and inflammatory cell infiltration were evaluated by ELISA and immunostaining, respectively.

RESULTS

RD resulted in increased generation of ROS. Treatment with 5 mg/kg edaravone significantly reduced the ROS level, along with a decrease in TUNEL-positive cells in the photoreceptor layer. A caspase assay also confirmed decreased activation of caspase-3, -8, and -9 in RD treated with edaravone. The level of the antiapoptotic Bcl-2 was increased in detached retinas after edaravone treatment, whereas the levels of the stress-activated p-ERK1/2 were decreased. In addition, edaravone treatment resulted in a significant decrease in the levels of TNF-α, MCP-1, and macrophage infiltration.

CONCLUSIONS

Oxidative stress plays an important role in photoreceptor cell death after RD. Edaravone treatment may aid in preventing photoreceptor cell death after RD by suppressing ROS-induced photoreceptor damage.

Targeting the mitochondrial permeability transition: cardiac ischemia-reperfusion versus carcinogenesis

Cardiovascular diseases and cancer continue to be major causes of death worldwide, and despite intensive research only modest progress has been reached in reducing the morbidity and mortality of these awful diseases. Mitochondria are broadly accepted as the key organelles that play a crucial role in cell life and death. They provide cells with ATP produced via oxidative phosphorylation under physiological conditions, and initiate cell death through both apoptosis and necrosis in response to severe stress. Oxidative stress accompanied by calcium overload and ATP depletion induces the mitochondrial permeability transition (mPT) with formation of pathological, non-specific mPT pores (mPTP) in the mitochondrial inner membrane. Opening of the mPTP with a high conductance results in matrix swelling ultimately inducing rupture of the mitochondrial outer membrane and releasing pro-apoptotic proteins into the cytoplasm. The ATP level is the determining factor in deciding whether cells die through apoptosis or necrosis. Cardiac cells undergoing ischemia followed by reperfusion (IR) possess exactly the same conditions mentioned above to induce mPTP opening. Due to its critical role in cell death, inhibition of mPTP opening has been accepted as a major therapeutic approach to protect the heart against IR. In contrast to cardiac IR, cancer cells exhibit less sensitivity to pore opening which can be in part explained by increased expression of mPTP compounds/modulators and metabolic remodeling. Since the main goal of chemotherapy is to provoke apoptosis, mPT induction may represent an attractive approach for the development of new cancer therapeutics to induce mitochondria-mediated cell death and prevent cell differentiation in carcinogenesis. This review focuses on the role of the mPTP in cardiac IR and cancer, and pharmacological agents to prevent or initiate mPT-mediated cell death, respectively in these diseases.

Unilateral ureteral obstruction evokes renal tubular apoptosis via the enhanced oxidative stress and endoplasmic reticulum stress in the rat

PURPOSE

Oxidative stress and endoplasmic reticulum (ER) stress may induce renal apoptosis and contribute to the pathogenesis of the kidney with unilateral ureteral obstruction (UUO).

MATERIALS AND METHODS

We induced UUO the female Wistar rats by ligation of the left ureter at the ureteropelvic junction. The UUO kidney was performed from 4 hr to 7 days course. At the indicated time, we measured the arterial blood pressure and renal blood flow in each rat, renal ROS measurement in vivo by a chemiluminescence analyzer. We performed immunohistochemistry of monocyte/macrophage (ED-1) stain for leukocyte infiltration, 4-hydroxynoneal (4-HNE) stain for ROS products, and apoptosis by terminal deoxynucleotidyl transferase-mediated nick-end labeling (TUNEL) and Western blot to analyze ER stress-associated and apoptosis-related proteins expression in the UUO kidney.

RESULTS

We found that UUO decreased renal blood flow and increased renal vascular resistance and renal ROS. UUO decreased renal manganese superoxide dismutase (MnSOD) and catalase protein expression in a time-dependent manner. Increased 4-HNE stain in the renal tubules and ED-1 stain in the renal tubulointerstitial compartment occurred after 4 hr of UUO in the kidney. UUO significantly enhanced ER stress markers like ER stress-response protein 25 and glucose-regulated protein 78 and ER-associated apoptosis proteins, c-JUN NH(2) -terminal kinase, and caspase 12, in the kidney. Subsequently, UUO enhanced renal pro-apoptotic Bax and caspase 3 expression and decreased anti-apoptotic Bcl-2 expression, leading to renal tubular apoptosis.

CONCLUSIONS

Our data suggest that renal tubular apoptosis induced by oxidative stress and ER stress occurred in the UUO kidney.

Mitochondrial involvement in cardiac apoptosis during ischemia and reperfusion: can we close the box?

Myocardial ischemia is the main cause of death in the Western societies. Therapeutic strategies aimed to protect the ischemic myocardium have been extensively studied. Reperfusion is the definitive treatment for acute coronary syndromes, especially acute myocardial infarction; however, reperfusion has the potential to exacerbate tissue injury, a process termed reperfusion injury. Ischemia/reperfusion (I/R) injury may lead to cardiac arrhythmias and contractile dysfunction that involve apoptosis and necrosis in the heart. The present review describes the mitochondrial role on cardiomyocyte death and some potential pharmacological strategies aimed at preventing the opening of the box, i.e., mitochondrial dysfunction and membrane permeabilization that result into cell death. Data in the literature suggest that mitochondrial disruption during I/R can be avoided, although uncertainties still exist, including the fact that the optimal windows of treatment are still fairly unknown. Despite this, the protection of cardiac mitochondrial function should be critical for the patient survival, and new strategies to avoid mitochondrial alterations should be designed to avoid cardiomyocyte loss.

Pathogenesis of myocardial ischemia-reperfusion injury and rationale for therapy

Since the initial description of the phenomenon by Jennings et al 50 years ago, our understanding of the underlying mechanisms of reperfusion injury has grown significantly. Its pathogenesis reflects the confluence of multiple pathways, including ion channels, reactive oxygen species, inflammation, and endothelial dysfunction. The purposes of this review are to examine the current state of understanding of ischemia-reperfusion injury, as well as to highlight recent interventions aimed at this heretofore elusive target. In conclusion, despite its complexity our ongoing efforts to mitigate this form of injury should not be deterred, because nearly 2 million patients annually undergo either spontaneous (in the form of acute myocardial infarction) or iatrogenic (in the context of cardioplegic arrest) ischemia-reperfusion.

Neuroprotective and antioxidative effect of cactus polysaccharides in vivo and in vitro

Cactus polysaccharides (CP), some of the active components in Opuntia dillenii Haw have been reported to display neuroprotective effects in rat brain slices. In the present study, we investigated the neuroprotective properties of CP and their potential mechanisms on brain ischemia-reperfusion injury in rats, and on oxidative stress-induced damage in PC12 cells. Male Sprague-Dawley rats with ischemia following middle cerebral artery occlusion and reperfusion were investigated. CP (200 mg/kg) significantly decreased the neurological deficit score, reduced infarct volume, decreased neuronal loss in cerebral cortex, and remarkably reduced the protein synthesis of inducible nitric oxide synthase which were induced by ischemia and reperfusion. Otherwise, the protective effect of CP was confirmed in in vitro study. CP protected PC12 cells against hydrogen peroxide (H(2)O(2)) insult. Pretreatment with CP prior to H(2)O(2) exposure significantly elevated cell viability, reduced H(2)O(2)-induced apoptosis, and decreased both intracellular and total accumulation of reactive oxygen species (ROS) production. Furthermore, CP also reversed the upregulation of Bax/Bcl-2 mRNA ratio, the downstream cascade following ROS. These results suggest that CP may be a candidate compound for the treatment of ischemia and oxidative stress-induced neurodegenerative disease.

Molecular Biology of Apoptosis in Ischemia and Reperfusion

This study reviews the current understanding of the mechanisms that mediate the complex processes involved in apoptosis secondary to ischemia and reperfusion (I/R) and is not intended as a complete literature review of apoptosis. Several biochemical reactions trigger a cascade of events, which activate caspases. These caspases exert their effect through downstream proteolysis until the final effector caspases mediate the nuclear features characteristic of apoptosis, DNA fragmentation and condensation. Within the context of ischemia, the hypoxic environment initiates the expression of several genes involved in inflammation, the immune response, and apoptosis. Many of these same genes are activated during reperfusion injury in response to radical oxygen species generation. It is plausible that inhibition of specific apoptotic pathways via inactivation or downregulation of those genes responsible for the initiation of inflammation, immune response, and apoptosis may provide promising molecular targets for ameliorating reperfusion injury in I/R-related processes. Such inhibitory mechanisms are discussed in this review. Important targets in I/R-related pathologies include the brain during stroke, the heart during myocardial infarction, and the organs during harvesting and/or storage for transplantation. In addition, we present data from our ongoing research of specific signal transduction-related elements and their role in ischemia/reperfusion injury. These data address the potential therapeutic application of anti-inflammatory and anti-ischemic compounds in the prevention of I/R damage.

Mitochondrial permeability transition pore opening as a promising therapeutic target in cardiac diseases

In addition to their central role in ATP synthesis, mitochondria play a critical role in cell death. Oxidative stress accompanied by calcium overload, ATP depletion, and elevated phosphate levels induces mitochondrial permeability transition (MPT) with formation of nonspecific MPT pores (MPTP) in the inner mitochondrial membrane. Pore opening results in mitochondrial dysfunction with uncoupled oxidative phosphorylation and ATP hydrolysis, ultimately leading to cell death. For the past 20 years, three proteins have been accepted as key structural components of the MPTP: adenine nucleotide translocase (ANT) in the inner membrane, cyclophilin D (CyP-D) in the matrix, and the voltage-dependent anion channel (VDAC) in the outer membrane. However, most recent studies have questioned the molecular identity of the pores. Genetic studies have eliminated the VDAC as an essential component of MPTP and attributed a regulatory (rather than structural) role to ANT. Currently, the phosphate carrier appears to play a crucial role in MPTP formation. MPTP opening has been examined extensively in cardiac pathological conditions, including ischemia/reperfusion as well as heart failure. Accordingly, MPTP is accepted as a therapeutic target for both pharmacological and conditional strategies to block pore formation by direct interaction with MPTP components or indirectly by decreasing MPTP inducers. Inhibition of MPTP opening by reduction of CyP-D activity by nonimmunosuppressive analogs of cyclosporine A or sanglifehrin A, as well as attenuation of reactive oxygen species accumulation through mitochondria-targeted antioxidants, is the most promising. This review outlines our current knowledge of the structure and function of the MPTP and describes possible approaches for cardioprotection.

Adenine nucleotide translocase-1 induces cardiomyocyte death through upregulation of the pro-apoptotic protein Bax

Overexpression of the adenine nucleotide translocase (ANT) has been shown to be cytotoxic in several cell types. Although ANT was originally proposed to be a critical component of the mitochondrial permeability transition (MPT) pore, recent data have suggested that this may not be the case. We therefore hypothesized that the cytotoxic actions of ANT are through an alternative mechanism, independent of the MPT pore. Infection of cultured neonatal cardiomyocytes with an ANT1-encoding adenovirus induced a gene dosage-dependent increase in cell death. However, ANT1 overexpression failed to induce MPT, and neither pharmacological nor genetic inhibition of the MPT pore was able to prevent ANT1-induced cell death. These data suggested that ANT1-induced death progressed through an MPT pore-independent pathway. Somewhat surprisingly, we observed that protein levels of Bax, a pro-apoptotic Bcl protein, were consistently elevated in ANT1-infected cardiomyocytes. Membranes isolated from ANT1-infected myocytes exhibited significantly increased amounts of membrane-inserted Bax, and immunocytochemistry revealed increased Bax activation in ANT1-infected myocytes. Co-expression with the Bax antagonist Bcl2 was able to greatly reduce the degree of ANT1-induced cell death. Furthermore, Bax/Bak-deficient fibroblasts were resistant to the cytotoxic effects of ANT1 overexpression. Interestingly, ANT1 overexpression was also associated with enhanced production of reactive oxygen species (ROS), and the antioxidant MnTBAP was able to significantly attenuate both the ANT1-induced upregulation of Bax and cell death. Taken together, these data indicate that ANT mediates cell death, not through the MPT pore, but rather via a ROS-dependent upregulation and activation of Bax.

Mitochondrial death effectors: relevance to sarcopenia and disuse muscle atrophy

Accelerated apoptosis in skeletal muscle is increasingly recognized as a potential mechanism contributing to the development of sarcopenia of aging and disuse muscle atrophy. Given their central role in the regulation of apoptosis, mitochondria are regarded as key players in the pathogenesis of myocyte loss during aging and other atrophying conditions. Oxidative damage to mitochondrial constituents, impaired respiration and altered mitochondrial turnover have been proposed as potential triggering events for mitochondrial apoptotic signaling. In addition, iron accumulation within mitochondria may enhance the susceptibility to apoptosis during the development of sarcopenia and possibly acute muscle atrophy, likely through exacerbation of oxidative stress. Mitochondria can induce myocyte apoptosis via both caspase-dependent and independent pathways, although the apoptogenic mediators involved may be different depending on age, muscle type and specific atrophying conditions. Despite the considerable advances made, additional research is necessary to establish a definite causal link between apoptotic signaling and the development of sarcopenia and acute atrophy. Furthermore, a translational effort is required to determine the role played by apoptosis in the pathogenesis of sarcopenia and disuse-induced muscle loss in human subjects.

Pretreatment with edaravone reduces lung mitochondrial damage in an infant rabbit ischemia-reperfusion model

PURPOSE

Free radical scavenger edaravone has been approved as a new drug for treatment of stroke patients. The purpose of this study was to examine whether pretreatment with edaravone could attenuate ischemia-reperfusion (IR)-induced lung damage in infant rabbits.

METHODS

New Zealand White rabbits (Experimental Animal Center, Nanjing Medical University, Nanjing, China) at age from 15 to 21 days were subjected to sham operation, IR, or edaravone plus IR. Ischemia/reperfusion was induced by clamping the right pulmonary hilum for 1 hour and then removal of the clamp for 4 hours. Edaravone (1 mg/kg, intravenous) was given 5 minutes before ischemia. Concentrations of reactive oxygen species-hydroxyl radical (ROS-HR) and malondialdehyde (MDA), and activities of glutathione peroxidase (GSH-PX) and superoxide dismutase (SOD) in the lung tissue were measured. Mitochondrial membrane potential, swelling rate, and ultrastructure of the lung were analyzed, and histologic condition of the lung was evaluated.

RESULTS

Edaravone pretreatment reduced markedly the productions of ROS-HR and MDA and increased the activities of GSH-PX and SOD. It attenuated both IR-induced decrease in mitochondrial membrane potential from 60% to 14% and IR-induced increase in mitochondrial swelling. As results, the mitochondrial and lung tissue damages were less, leading to an improved survival rate in IR rabbits pretreated with edaravone compared with IR rabbits without the treatment.

CONCLUSION

Edaravone pretreatment reduces the IR-induced lung mitochondrial damage in infant rabbits.

Edaravone prevents Fas-induced fulminant hepatic failure in mice by regulating mitochondrial Bcl-xL and Bax

Fulminant hepatic failure is a serious disease that has a poor cure rate unless liver transplantation is performed. Edaravone, a free radical scavenger, has been approved for the treatment of acute cerebral infarction, and its mechanism of action involves scavenging free radicals generated in ischemic tissues. We assessed the ability of 3-methyl-1-phenyl-2-pyrazolim-5-one (edaravone) to prevent Fas-induced acute liver failure in mice and examined the mechanisms underlying the observed effects. BALB/c mice were administered 0.25 microg/g (i.v.) body weight of a purified hamster agonist anti-Fas monoclonal antibody (clone Jo2). The mice also received either edaravone or isotonic sodium chloride solution before or after Jo2 treatment. Edaravone improved the survival rate of the mice markedly. Histopathological findings and serum aspartate aminotransferase levels showed that edaravone reduced the degree of liver injury caused by Jo2. Terminal deoxynucleotidyl transferase-mediated 2'-deoxyuridine 5'-triphosphate nick end labeling staining showed that edaravone reduced the number of apoptotic hepatocytes. Edaravone also prevented cytochrome c release and caspase 3 activity, recognized as markers of apoptosis after mitochondrial disruption. Therefore, we considered that the antiapoptotic activity of edaravone involved blocking signals in the mitochondria-dependent pathway of Fas-induced apoptosis. Mitochondrial Bcl-xL and Bax, which form a channel in the mitochondrial membrane and, by their balance, regulate its permeability, are involved in mitochondrial disruption. Western blotting showed that the Bcl-xL-Bax ratio of the edaravone group was much higher than that of the control group. In conclusion, edaravone might protect hepatocytes from Fas-induced mitochondria-dependent apoptosis by regulating mitochondrial Bcl-xL and Bax.

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.

Biphasic elevation of bilirubin oxidation during myocardial ischemia reperfusion

BACKGROUND

The time course of oxidative stress involving nitric oxide (NO) after myocardial ischemia reperfusion (MIR) has not been elucidated in detail, so the present study was designed to assess the dynamics of oxidative stress after MIR, urinary excretion of oxidized bilirubin metabolites (ie, biopyrrins) and their generation in various organs.

METHODS AND RESULTS

Rat models of MIR were created by occluding the left coronary artery for 30 min followed by 48 h of reperfusion. Levels of urinary biopyrrins increased biphasically at 8 h and 24 h after MIR. Biopyrrins were upregulated in the lungs at 8 h after MIR, according to immunohistochemistry and ELISA, and at 24 h biopyrrin expression was increased in the heart and lungs. The NO synthase inhibitor, NG-monomethyl-L-arginine, significantly diminished biopyrrin synthesis in the heart and lungs at 24 h, but not in the lungs at 8 h after MIR. Hemodynamic assessment revealed increased left ventricle end-diastolic pressure, suggesting that lung congestion influences pulmonary biopyrrin formation.

CONCLUSIONS

The dynamics of urinary biopyrrins might reflect earlier biopyrrin generation in the lungs and delayed formation in both the lungs and heart when NO is involved. Therefore, urinary biopyrrins can serve as a useful marker of systemic oxidative stress after MIR.

Neuroprotective effects of edaravone-administration on 6-OHDA-treated dopaminergic neurons

Background

Parkinson's disease (PD) is a neurological disorder characterized by the degeneration of nigrostriatal dopaminergic systems. Free radicals induced by oxidative stress are involved in the mechanisms of cell death in PD. This study clarifies the neuroprotective effects of edaravone (MCI-186, 3-methyl-1-phenyl-2-pyrazolin-5-one), which has already been used for the treatment of cerebral ischemia in Japan, on TH-positive dopaminergic neurons using PD model both in vitro and in vivo. 6-hydroxydopamine (6-OHDA), a neurotoxin for dopaminergic neurons, was added to cultured dopaminergic neurons derived from murine embryonal ventral mesencephalon with subsequet administration of edaravone or saline. The number of surviving TH-positive neurons and the degree of cell damage induced by free radicals were analyzed. In parallel, edaravone or saline was intravenously administered for PD model of rats receiving intrastriatal 6-OHDA lesion with subsequent behavioral and histological analyses.

Results

In vitro study showed that edaravone significantly ameliorated the survival of TH-positive neurons in a dose-responsive manner. The number of apoptotic cells and HEt-positive cells significantly decreased, thus indicating that the neuroprotective effects of edaravone might be mediated by anti-apoptotic effects through the suppression of free radicals by edaravone. In vivo study demonstrated that edaravone-administration at 30 minutes after 6-OHDA lesion reduced the number of amphetamine-induced rotations significantly than edaravone-administration at 24 hours. Tyrosine hydroxylase (TH) staining of the striatum and substantia nigra pars compacta revealed that edaravone might exert neuroprotective effects on nigrostriatal dopaminergic systems. The neuroprotective effects were prominent when edaravone was administered early and in high concentration. TUNEL, HEt and Iba-1 staining in vivo might demonstrate the involvement of anti-apoptotic, anti-oxidative and anti-inflammatory effects of edaravone-administration.

Conclusion

Edaravone exerts neuroprotective effects on PD model both in vitro and in vivo. The underlying mechanisms might be involved in the anti-apoptotic effects, anti-oxidative effects, and/or anti-inflammatory effects of edaravone. Edaravone might be a hopeful therapeutic option for PD, although the high therapeutic dosage remains to be solved for the clinical application.