Decreased neutrophil antioxidative enzyme activities and increased lipid peroxidation in hyperlipoproteinemic human subjects

Neutrophils have the capacity to produce free radicals. Free radicals are a ssociated with hyperlipoproteinemia and atherosclerotic processes. For this reason, neutrophil superoxide dismutase (SOD), glutathione peroxidase (GSH -Px), glutathione reductase (GR), catalase (Cat) activities and thiobarbitu ric acid reactive substances (TBARS), as an index of lipid peroxidation, ha ve been studied in hyperlipoproteinemic (HLP) and age-matched normolipidemi c groups. Lipid parameters including triglycerides, total cholesterol, plas ma TBARS, HDL-cholesterol, LDL-cholesterol, apo A-I, apo B have also been d etermined. Forty subjects (females 18, males 22) with HLP (mean age 43.8+/- 8.7 (S.D.)) and 40 normolipoproteinemic subjects (females 17, males 23; mea n age 46.4+/-11) were included in the study. Neutrophils were isolated by P ercoll gradient centrifugation from venous blood samples. Methods used were as follows: INT method for SOD, UV method at 340 nm based on oxidation of NADPH for GSH-Px and GR, UV method at 240 nm based on degradation of hydrog en peroxide for catalase, and a method based on reaction with thiobarbituri c acid for TEARS. Neutrophil SOD, GSH-Px, and catalase activities were foun d to be significantly low in the hyperlipoproteinemic group compared with t he normolipoproteinemic group. CR activity did not differ between both grou ps. The mean TEARS level in the neutrophil fraction was found to be signifi cantly higher in hyperlipoproteinemics than in that of the normolipoprotein emics. It was concluded that decreased neutrophil antioxidant enzyme activi ties in hyperlipoproteinemics may lead to insufficient detoxification of fr ee radicals produced in these cells and contribute to increased lipid perox idation. (C) 1999 Elsevier Science B.V. All rights reserved.