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https://www.arca.fiocruz.br/handle/icict/17857
OXIDATIVE STRESS IN SEPSIS. POSSIBLE PRODUCTION OF FREE RADICALS THROUGH AN ERYTHROCYTE-MEDIATED POSITIVE FEEDBACK MECHANISM
Author
Affilliation
Fundação Oswaldo Cruz. Centro de Pesquisas Gonçalo Moniz. Salvador, BA, Brasil
Fundação Oswaldo Cruz. Centro de Pesquisas Gonçalo Moniz. Salvador, BA, Brasil
Universidade Federal da Bahia. Salvador, BA, Brasil
Fundação Oswaldo Cruz. Centro de Pesquisas Gonçalo Moniz. Salvador, BA, Brasil
Fundação Oswaldo Cruz. Centro de Pesquisas Gonçalo Moniz. Salvador, BA, Brasil
Universidade Federal da Bahia. Salvador, BA, Brasil
Fundação Oswaldo Cruz. Centro de Pesquisas Gonçalo Moniz. Salvador, BA, Brasil
Abstract
Sepsis is an illness with a high morbidity for which no effective treatment exists. Its treatment has a high cost because it usually requires an intensive care unit and expensive antibiotics. The present study focus in the production of reactive oxygen species in the early stages of sepsis. This study aimed at investigating the production of reactive oxygen specie during the inflammatory response in patients with sepsis.Methods: Reactive oxygen specie production and insoluble myeloperoxidase obtained fromfresh whole blood were measured by photon counting chemiluminescence in the blood of18 septic patients and 12 healthy individuals. Modified red blood cells were evaluated bystaining of blood smears. The production of reactive oxygen species by macrophages andpolymorphonuclear leukocytes put into contact with modified red blood cells were alsoassessed by photon counting chemiluminescence.Results: The appearance of oxidatively modified erythrocytes, which is an evidence ofoxidative stress, was supported by the detection of reactive oxygen species and insolublemyeloperoxidase in the whole blood of all septic patients. Peroxynitrite was the main reac-tive oxygen species found in the whole blood. Oxidatively modified erythrocytes activatedphagocytic cells in vitro, leading to the considerable production of free radicals.Conclusion: It was found that sepsis led to a high oxidative stress and to extensive modifi-cation of erythrocytes. It is proposed that a positive feedback mechanism, involving theactivation of circulating leukocytes by these modified erythrocytes would maintain thepro-oxidative state even after the disappearance of bacteria.
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