Implicações do estresse oxidativo sobre o metabolismo eritrocitário de pessoas com Síndrome de Down

Abstract

Down's Syndrome carriers are under endogenous and chronic oxidative stress that can result from an excessive SOD-1enzyme activity. This work describes some indicators and adaptations of the defense system faced with oxidative damage. We observed that, in Down's Syndrome individuals, the presence of oxidative stress (with an increase of 48% in the SOD-1 activity) induced several adaptations of the erythrocyte metabolism, with a reduction of methemoglobin, through an increase of methemoglobin reductase activity (29%) which guaranteed the efficiency of oxygen transportation. The increase of GSH (61%) would propitiate the maintenance of the integrity of the membrane, essential to the functional integrity of erythrocytes. The decrease in the hemoglobin and hematocrit concentrations, possibly, results from the increase in the activity of the glucose-6- phosphate dehydrogenase enzyme, and a reduction in the half-life of erythrocytes. The effects of these adaptations on blood oxygenation require further investigations.