Effect of the aminosteroid U74006F after cardiopulmonary arrest in dogs

The oxygen free radical-induced lipid peroxidative reactions that occur during resuscitation from normothermic cardiac arrest may contribute to the degree of neurologic dysfunction sustained. A blinded, randomized experimental trial was performed to determine whether U74006F, a potent inhibitor of lipid peroxidation, reduces morbidity and 24-hour mortality after 10 minutes of normothermic cardiopulmonary arrest; ventricular fibrillation was induced by electrical stimulation in 24 open-chest, halothane-anesthetized dogs, and circulation was reestablished by direct cardiac compressions, administration of a standardized drug regime, and internal countershocks. When spontaneous circulation was restored, a bolus injection of 1.5 mg/kg U74006F (n = 12) or 25 mM citrate vehicle (n = 12) was infused intravenously in 15 minutes and an infusion was continued at 0.125 mg/kg/hr for the next 12 hours. In the drug-treated group, plasma U74006F concentration averaged 0.13 µg/ml between 3 and 12 hours after cardiac arrest. By 24 hours after arrest, 10 of 12 (83%) vehicle-treated dogs had died but only four of 12 (33%) U74006F-treated dogs had died (p=0.017). U74006F-treated dogs survived significantly longer (mean ± SEM 22 ± 1 hr) than vehicle-treated dogs (18 ± 1 hr), with significantly better neurologic function 1, 2, and 24 hours after arrest. Plasma fatty acid hydroperoxide concentrations 12 hours after arrest were 88 ±81 pmol/ml in U74006F-treated and 241 ± 49 pmol/ml in vehicle-treated dogs (p<0.05). Vitamin E concentrations were significantly higher in the plasma of U74006F-treated dogs 2, 3, and 6 hours after arrest compared with vehicle-treated dogs. We conclude that the nonglucocorticoid 21-aminosteroid U74006F reduces mortality and sensorimotor deficit after transient global cerebral ischemia, perhaps by inhibiting lipid hydroperoxide formation.