allopurinol and Shock--Septic

Post-translational modification of proteins due to exposure to radicals and other reactive species are markers of metabolic and inflammatory oxidative stress such as sepsis. This study uses the nitrone spin-trap DMPO and a combination of immuno-spin trapping and mass spectrometry to identify in vivo products of radical reactions in mice. We report the detection of dose-dependent production of DMPO-carboxypeptidase B1 (CPB1) adducts in the spleens of mice treated with lipopolysaccharide (LPS). Additionally, we report significant detection of DMPO-CPB1 adducts in mice experiencing normal physiological conditions. Treatments with inhibitors and experiments with knock-out mice indicate that xanthine oxidase and endothelial nitric oxide synthase are important sources of the reactive species that lead to CPB1 adduct formation. We also report a significant loss of CPB1 activity following LPS challenge in conjunction with an increase in CPB1 protein accumulation. This suggests the presence of a possible mechanism for CPB1 activity loss with compensatory protein production.

Topics: Allopurinol; Amidines; Animals; Benzylamines; Carboxypeptidase B; Cross-Linking Reagents; Cyclic N-Oxides; Electron Spin Resonance Spectroscopy; Free Radicals; Immunoprecipitation; Lipopolysaccharides; Male; Mass Spectrometry; Mice; Mice, Inbred C57BL; Mice, Knockout; Nitric Oxide Synthase Type III; Protein Processing, Post-Translational; Shock, Septic; Spleen; Xanthine Oxidase

Myocardial dysfunction contributes to the high mortality of patients with endotoxemia. Although nitric oxide (NO) has been implicated in the pathogenesis of septic cardiovascular dysfunction, the role of myocardial NO synthase 3 (NOS3) remains incompletely defined. Here we show that mice with cardiomyocyte-specific NOS3 overexpression (NOS3TG) are protected from myocardial dysfunction and death associated with endotoxemia. Endotoxin induced more marked impairment of Ca(2+) transients and cellular contraction in wild-type than in NOS3TG cardiomyocytes, in part, because of greater total sarcoplasmic reticulum Ca(2+) load and myofilament sensitivity to Ca(2+) in the latter during endotoxemia. Endotoxin increased reactive oxygen species production in wild-type but not NOS3TG hearts, in part, because of increased xanthine oxidase activity. Inhibition of NOS by N(G)-nitro-l-arginine-methyl ester restored the ability of endotoxin to increase reactive oxygen species production and xanthine oxidase activity in NOS3TG hearts to the levels measured in endotoxin-challenged wild-type hearts. Allopurinol, a xanthine oxidase inhibitor, attenuated endotoxin-induced reactive oxygen species accumulation and myocardial dysfunction in wild-type mice. The protective effects of cardiomyocyte NOS3 on myocardial function and survival were further confirmed in a murine model of polymicrobial sepsis. These results suggest that increased myocardial NO levels attenuate endotoxin-induced reactive oxygen species production and increase total sarcoplasmic reticulum Ca(2+) load and myofilament sensitivity to Ca(2+), thereby reducing myocardial dysfunction and mortality in murine models of septic shock.

Topics: Actin Cytoskeleton; Allopurinol; Animals; Calcium; Calcium-Binding Proteins; Cardiotonic Agents; Endotoxemia; Endotoxins; Enzyme Inhibitors; Heart; Heart Diseases; Male; Mice; Mice, Inbred C57BL; Mice, Transgenic; Myocardial Contraction; Myocardium; Myocytes, Cardiac; Nitric Oxide; Nitric Oxide Synthase Type II; Nitric Oxide Synthase Type III; Phosphorylation; Reactive Oxygen Species; Sarcoplasmic Reticulum; Shock, Septic; Xanthine Oxidase

Topics: Adenosine; Allopurinol; Animals; Glutathione; Graft Survival; Insulin; Intestinal Obstruction; Liver; Liver Transplantation; Male; Organ Preservation; Organ Preservation Solutions; Portasystemic Shunt, Surgical; Raffinose; Rats; Rats, Wistar; Shock, Septic

Topics: Animals; Dogs; Dopamine; Escherichia coli Infections; Fluid Therapy; Free Radicals; Hemodynamics; Ibuprofen; Lipid Peroxidation; Nitriles; Oxamic Acid; Sepsis; Shock, Septic; Superoxides; Tromethamine; Xanthine Oxidase

The effect of allopurinol pretreatment 12 hours before an intraperitoneal challenge with a sublethal dose of Escherichia coli endotoxin (50 micrograms kg-1) was evaluated in 18 horses. The horses were divided among three equal groups: 1-endotoxin alone; 2-5 mg allopurinol kg-1 bodyweight plus endotoxin; and 3-50 mg allopurinol kg-1 bodyweight plus endotoxin. A variety of evaluation parameters were used. No differences among the groups were noted in rectal temperature, heart rate, respiration rate, haematological values, blood PaO2, blood PaCO2, blood pH or blood bicarbonate. Significant (P less than 0.05) differences between the groups were noted as regards the changes in capillary refill time, base excess, blood glucose, blood lactate, blood beta-glucuronidase and recumbency time. The protection afforded by 5 mg allopurinol kg-1 appeared to be superior to that with 50 mg allopurinol kg-1.

Topics: Allopurinol; Animals; Blood Gas Analysis; Blood Glucose; Body Temperature; Disease Models, Animal; Endotoxins; Escherichia coli; Female; Glucuronidase; Heart Rate; Hematocrit; Horse Diseases; Horses; Hydrogen-Ion Concentration; Lactates; Leukocyte Count; Lipopolysaccharides; Male; Respiration; Shock, Septic

The accumulation of lipoperoxide (LPO) is reported to occur in the organs of animals with endotoxemia, where it is accompanied by an activation of xanthine oxidase (XOD) and a depletion of superoxide dismutase (SOD). In the present study, three measures of preventing LPO accumulation, ie, prior treatment with a XOD inhibitor, exogenous supply of enzymatic scavengers, and supplementation with chemical quenchers, were investigated to determine how to improve the survival rate of rats with lethal endotoxemia. Thirty minutes after treatment with various doses of allopurinol, SOD, catalase (CAT), vitamin E (VE), and reduced glutathione (GSH), adult male Wistar rats were subjected to endotoxemia by an intraperitoneal injection of 0.4 mg/100 g of Escherichia coli endotoxin. Allopurinol did not improve survival rates, denoting a lower level of XOD and an almost normal level of SOD in the liver. SOD (9,000 U/100 g) with or without CAT (4,000 U/100 g) markedly increased the survival rate of rats, with complete inhibition of hepatic LPO accumulation and suppression of XOD activity. CAT alone had no salutary effects on survival rate or hepatic LPO. Large amounts of VE (100 mg/100 g) or GSH (50 mg/100 g) slightly suppressed the accumulation of LPO in the liver but had no effect on survival rate. In that exogenous SOD has been considered not to penetrate the cellular membrane because of its high molecular weight, the results suggest that the extracellular spaces are the site of SOD action. Lipid peroxidation of the biomembrane initiated by oxygen free radicals released into extra-cellular space from phagocytes may play an important role in the development of lethality in experimental endotoxemia.

Topics: Allopurinol; Animals; Catalase; Endotoxins; Glutathione; Lipid Peroxides; Liver; Lysosomes; Male; Rats; Rats, Inbred Strains; Shock, Septic; Superoxide Dismutase; Superoxides; Vitamin E; Xanthine Oxidase

Since oxygen free radicals may have a role in the pathophysiology of endotoxin shock, we have studied the effects of a wide range of compounds (alpha-tocopherol, reduced glutathione, allopurinol, superoxide dismutase (alone or in combination with catalase) and phenyl butylnitrone) that can act either to remove free radicals as they are generated or to prevent their generation. The effects of these substances on the metabolic and cardiovascular responses to endotoxin were examined in conscious rats. The intravenous infusion of endotoxin (10 mg/kg i.v. given over 4 h) resulted in systemic hypotension, transient tachycardia, an increase in plasma lactate, and an initial hyperglycemia followed, in those rats that died before 24 h, by hypoglycemia. The hypotension and tachycardia produced by endotoxin were not significantly modified by alpha-tocopherol, allopurinol, or superoxide dismutase, alone or in combination with catalase. The tachycardia was attenuated by reduced glutathione and phenyl butylnitrone. alpha-Tocopherol attenuated the initial hyperglycemia produced by endotoxin whilst alpha-tocopherol, allopurinol, and phenyl butylnitrone all significantly attenuated the endotoxin-induced increase in plasma lactate. Among the free radical scavenging systems studied, only alpha-tocopherol and phenyl butylnitrone improved survival. These results suggest a contribution from oxygen-free radicals to the pathophysiology of endotoxemia.

Topics: Allopurinol; Animals; Blood Glucose; Cardiovascular Physiological Phenomena; Cardiovascular System; Catalase; Cyclic N-Oxides; Endotoxins; Free Radicals; Glutathione; Lactates; Lactic Acid; Male; Nitrogen Oxides; Oxygen; Prostaglandins; Rats; Rats, Inbred Strains; Shock, Septic; Superoxide Dismutase; Vitamin E

Wistar strain rats were treated with E. coli endotoxin by intraperitoneal injection (1 mg/100g body weight). Three hours after injection, the livers were excised to determine lipoperoxide concentration and superoxide dismutase activity. A significant elevation of lipoperoxide concentration and a marked reduction of superoxide dismutase activity were observed. Treatment with xanthine oxidase inhibitor were observed. Treatment with xanthine oxidase inhibitor allopurinol (10 mg/100g) 20 minutes prior the injection of endotoxin inhibited the elevation of lipoperoxide and the reduction of superoxide dismutase induced by endotoxin. Pretreatment of free radical scavengers such as reduced glutathione and alpha-tocopherol prevented the accumulation of lipoperoxide in the liver. Reduced glutathione protected the hepatic superoxide dismutase from decrease by endotoxin treatment. However, alpha-tocopherol did not maintain liver superoxide dismutase activity following the injection of endotoxin. These results indicate that endotoxemia gives rise to the accumulation of hepatic lipoperoxide by the activation of a production system and impairment of an elimination system of superoxide radicals.

Topics: Allopurinol; Animals; Endotoxins; Escherichia coli; Limulus Test; Lipid Peroxides; Liver; Rats; Rats, Inbred Strains; Shock, Septic; Superoxide Dismutase

Allopurinol, a xanthine-oxidase inhibitor and potential cell-stabilizing compound, was studied as a possible therapeutic agent in canine endotoxin shock. Circulatory collapse was produced in anesthetized mongrel dogs by IV administration of an LD75 dose of endotoxin. Treatment, with dextran alone, or with dextran and an IV bolus of allopurinol, was initiated 15 minutes after the onset of shock. The administration of 25, 50, or 100 mg/kg of IV allopurinol, accompanied by adequate volume replenishment, produced a significant reduction in the total peripheral vascular resistance and significant increases in cardiac output, blood glucose concentration, and arterial lactate concentration. Survival was not enhanced by allopurinol therapy, and allopurinol administration in normal dogs did not affect the vascular tone or the arterial lactic acid concentration. There was a transient hyperglycemic response and a decrease in the cardiac index in normal animals. The infusion of a postassium-insulin solution, in association with 100 mg/kg of allopurinol, did not significantly improve survival. In summary, although a number of potentially beneficial hemodynamic and metabolic effects were observed following allopurinol administration, survival in canine endotoxin shock was not enhanced.

Topics: Allopurinol; Animals; Dextrans; Dogs; Fluid Therapy; Hemodynamics; Shock, Septic

Topics: Aged; Allopurinol; Assisted Circulation; Humans; Intra-Aortic Balloon Pumping; Male; Shock, Septic