flavin-mononucleotide and Reperfusion-Injury

Ischemic brain injury is characterized by 2 temporally distinct but interrelated phases: ischemia (primary energy failure) and reperfusion (secondary energy failure). Loss of cerebral blood flow leads to decreased oxygen levels and energy crisis in the ischemic area, initiating a sequence of pathophysiological events that after reoxygenation lead to ischemia/reperfusion (I/R) brain damage. Mitochondrial impairment and oxidative stress are known to be early events in I/R injury. However, the biochemical mechanisms of mitochondria damage in I/R are not completely understood.. We used a mouse model of transient focal cerebral ischemia to investigate acute I/R-induced changes of mitochondrial function, focusing on mechanisms of primary and secondary energy failure.. Ischemia induced a reversible loss of flavin mononucleotide from mitochondrial complex I leading to a transient decrease in its enzymatic activity, which is rapidly reversed on reoxygenation. Reestablishing blood flow led to a reversible oxidative modification of mitochondrial complex I thiol residues and inhibition of the enzyme. Administration of glutathione-ethyl ester at the onset of reperfusion prevented the decline of complex I activity and was associated with smaller infarct size and improved neurological outcome, suggesting that decreased oxidation of complex I thiols during I/R-induced oxidative stress may contribute to the neuroprotective effect of glutathione ester.. Our results unveil a key role of mitochondrial complex I in the development of I/R brain injury and provide the mechanistic basis for the well-established mitochondrial dysfunction caused by I/R. Targeting the functional integrity of complex I in the early phase of reperfusion may provide a novel therapeutic strategy to prevent tissue injury after stroke.

Topics: Animals; Brain; Brain Ischemia; Cerebrovascular Circulation; Citrate (si)-Synthase; Disease Models, Animal; Electron Transport Complex I; Energy Metabolism; Flavin Mononucleotide; Glutathione; Infarction, Middle Cerebral Artery; Male; Mice; Mitochondria; Oxidative Stress; Random Allocation; Reperfusion Injury; Sulfhydryl Compounds

The influence of metabolic drug Cytoflavin (CF) with antihypoxic and antioxidative properties on human dermal fibroblasts in a model of ischemia-reoxygenation in vitro was studied. It was revealed that the restoration of ATP synthesis in fibroblasts in the postischemic period was considerably accelerated (in 2.1 times) by the addition of CF to the culture medium. The drug had a cell protective effect of reducing cell mortality during the reoxygenation after ischemia by 2-2.7 times. CF effectively reduced the level of reactive oxygen species (ROS) in fibroblasts after H2O2 treatment which allowed maintaining their survival at the level of control cells. Pretreatment of the cells with CF for one day ensured the maintenance of normal levels of ROS during the investigated time period in the fibroblasts subjected to H2O2 treatment, and reduced H2O2-induced cell death by almost a third compared to control cells. The introduction of CF in culture medium after ischemia showed no influence on Hsp70 synthesis, but led to decrease in GRP78 synthesis, raised after ischemia, to the control level, indicating a resolve of the endoplasmic reticulum (ER) stress and functional normalization of ER.

Topics: Adenosine Triphosphate; Antioxidants; Blotting, Western; Cell Culture Techniques; Cell Cycle; Cell Proliferation; Cell Survival; Cells, Cultured; Culture Media, Serum-Free; Data Interpretation, Statistical; Drug Combinations; Electrophoresis, Polyacrylamide Gel; Endoplasmic Reticulum Chaperone BiP; Energy Metabolism; Fibroblasts; Flavin Mononucleotide; Flow Cytometry; Heat-Shock Proteins; HSP70 Heat-Shock Proteins; Humans; Hydrogen Peroxide; Inosine Diphosphate; Models, Biological; Niacinamide; Oxidative Stress; Oxygen; Reactive Oxygen Species; Reperfusion Injury; Skin; Succinates

Topics: Aged; Brain; Carotid Arteries; Carotid Stenosis; Drug Combinations; Endarterectomy, Carotid; Female; Flavin Mononucleotide; Heme; Humans; Hypoxia-Ischemia, Brain; Inosine Diphosphate; Male; Middle Aged; Neuroprotective Agents; Niacinamide; Reperfusion Injury; Succinates

Experiment carried out on laboratory animals (rats) were aimed at comparative evaluation of the effect of several neuroprotective drugs under the conditions of model brain ischemia-reperfusion. The experimental methods included staining of brain tissue sections by hematoxiline-eosine, Nissl staining, and expression of NOS1, NOS3, TRAIL by imunnohistological means. The intensity of damage in various parts of brain and the nature of apoptosis without neuroprotection and with popular neuroprotectors (cytoflavin, actovegin, mexidol) and a test drug at the stage ofpreclinical trial (AKF-90-7) were evaluated. Characteristic cytotoxic (coagulative pycnomorphic and colliquative necrosis of neurons) and vascular (hemostasia, erythropedesis) changes were revealed. The neuroprotective effectof drugs decreases in the following order: AKF-90-7 > cytoflavin > actovegin > mexidol.

Topics: Animals; Brain; Drug Combinations; Drug Evaluation, Preclinical; Eosine Yellowish-(YS); Flavin Mononucleotide; Glycine; Hematoxylin; Heme; Hemostasis; Immunohistochemistry; Inosine Diphosphate; Male; Necrosis; Neurons; Neuroprotective Agents; Niacinamide; Nitric Oxide Synthase Type I; Nitric Oxide Synthase Type III; Picolines; Rats; Rats, Inbred Strains; Reperfusion Injury; Succinates; TNF-Related Apoptosis-Inducing Ligand

An analysis of experimental investigations carried out in 32 dogs and 30 rabbits and laboratory data of 242 patients has shown that the application of antioxidant and antihypoxic medicines decrease reperfusion lesions and endotoxicosis in operative treatment of acute intestinal obstruction.

Topics: Acute Disease; Animals; Digestive System Surgical Procedures; Disease Models, Animal; Dogs; Drug Combinations; Flavin Mononucleotide; Humans; Infusions, Intravenous; Inosine Diphosphate; Intestinal Obstruction; Intestine, Small; Male; Middle Aged; Niacinamide; Rabbits; Reperfusion Injury; Succinates; Treatment Outcome

Cytoflavin and neuronol produce vasoactive and neuroprotective effects in rats with cerebral ischemia. Vasoactive activity of neuronol was higher than that of cytoflavin. These differences were most pronounced at the level of microcirculation. Test preparations were equally potent in producing the neuroprotective effect. Cytoflavin and neuronol markedly decreased the mortality rate of animals. Over the first 6 h of ischemia the relative effectiveness of cytoflavin was higher than that of neuronol. However, neuronol exceeded cytoflavin in the relative effectiveness during the follow-up period (days 1-21).

Topics: Animals; Brain; Brain Ischemia; Cerebrovascular Circulation; Drug Combinations; Flavin Mononucleotide; Inosine Diphosphate; Male; Neuroprotective Agents; Niacinamide; Rats; Regional Blood Flow; Reperfusion Injury; Succinates; Succinic Acid; Survival Rate

Topics: Animals; Antioxidants; Drug Combinations; Energy Metabolism; Flavin Mononucleotide; Inosine Diphosphate; Lipid Peroxidation; Male; Meglumine; Neuroprotective Agents; Rats; Reperfusion Injury; Succinic Acid

The present studies examined the hypothesis that the distribution of cerebral injury after a focal ischemic insult is associated with the regional distribution of nitric oxide synthase (NOS) activity.. Based on previous studies that certain anatomically well-defined areas are prone to become either core or penumbra after middle cerebral artery occlusion (MCAO), we measured NOS activity in these areas from the right and left hemispheres in a spontaneously hypertensive rat filament model. Four groups were studied: (1) controls (immediate decapitation); (2) 1.5 hours of MCAO with no reperfusion (R0); (3) 1.5 hours of MCAO with 0.5 hour of reperfusion (R0.5); and (4) 1.5 hours of MCAO with 24 hours of reperfusion (R24). Three groups of corresponding isoflurane sham controls were also included: 1.5 (S1.5) or 2 (S2.0) hours of anesthesia and 1.5 hours of anesthesia+24 hours of observation (S24).. Control core NOS activity for combined right and left hemispheres was 129% greater than penumbral NOS activity (P<0.05). Combined core NOS activity was also greater (P<0.05) in the three sham groups: 208%, 122%, and 161%, respectively. In the three MCAO groups, ischemic and nonischemic core NOS remained higher than penumbral regions (P<0.05). However, NOS activity was lower in the ischemic than in the nonischemic core in all three groups: R0 (29% lower), R0.5 (48%), and R24 (86%) (P<0.05). Addition of cofactors (10 micromol/L tetrahydrobiopterin, 3 micromol/L flavin adenine dinucleotide, and 3 micromol/L flavin mononucleotide) increased NOS activity in all groups and lessened the decrease in ischemic core and penumbral NOS.. Greater NOS activity in core regions could explain in part the increased vulnerability of that region to ischemia and could theoretically contribute to the progression of the infarct over time. The data also suggest that NOS activity during ischemia and reperfusion could be influenced by the availability of cofactors.

Topics: Anesthetics, Inhalation; Animals; Antioxidants; Arterial Occlusive Diseases; Biopterins; Brain Ischemia; Cerebral Arteries; Cricetinae; Flavin Mononucleotide; Flavin-Adenine Dinucleotide; Isoflurane; Male; Nitric Oxide Synthase; Nitric Oxide Synthase Type III; Rats; Rats, Inbred SHR; Reperfusion; Reperfusion Injury; Time Factors

In the past, antioxidant and chelator studies have implicated a role for iron-dependent oxidative damage in tissues subjected to ischaemia followed by reperfusion. As ferritin is a major source of iron in non-muscular organs and therefore a potential source of the iron required for oxygen radical chemistry, we have determined conditions under which ferritin iron reduction leads to the formation of a pool of iron which is capable of catalysing lipid peroxidation. Under anaerobic conditions and in the presence of rat liver microsomes, flavin mononucleotide (FMN) catalysed the reduction of ferritin iron as shown by both continuous spectrophotometric measurements of tris ferrozine-Fe(II) complex formation and post-reaction Fe(II) determination. The presence of either ferrozine or citrate was not found to alter the time course or extent of ferritin reduction. In contrast, the addition of air to the reactants after a 20 min period of anaerobic reduction resulted in peroxidation of the microsome suspension (as determined with the 2-thiobarbituric acid test) only in the presence of a chelator such as citrate, ADP or nitrilotriacetic acid. These results support the concept that reduced ferritin iron can mediate oxidative damage during reperfusion of previously ischaemic tissues, provided that chelating agents such as citrate or ADP are present.

Topics: Animals; Catalysis; Ferritins; Flavin Mononucleotide; Free Radicals; Iron Chelating Agents; Lipid Peroxidation; Microsomes, Liver; Oxidation-Reduction; Rats; Rats, Sprague-Dawley; Reactive Oxygen Species; Reperfusion Injury; Thiobarbiturates