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Higher levels of antioxidant defenses in enalapril-treated versus non–enalapril-treated hemodialysis patients

1999; Elsevier BV; Volume: 34; Issue: 3 Linguagem: Inglês

10.1016/s0272-6386(99)70071-5

1523-6838

Elena M.V. de Cavanagh, León Ferder, Fernando Carrasquedo, David Scrivo, Alfredo Wassermann, César G. Fraga, Felipe Inserra,

Iron Metabolism and Disorders

We previously reported chronic treatment with angiotensin-converting enzyme inhibitors (ACEis) increases antioxidant defenses in mice. In the present study, however, we examined various antioxidant defenses in chronic hemodialysis (HD) patients either treated with enalapril (10 mg/d) for at least 6 months (+ACEi; n = 11) or untreated (–ACEi; n = 11). The relationship between antioxidant status and HD was investigated by determining oxidative stress markers and antioxidant defenses in a group of chronic HD patients (n = 33) and a group of age-matched controls (n = 29). The effect of a single HD session on those parameters was also evaluated. Before an HD session (pre-HD), HD patients had significantly lower levels of red blood cell (RBC) glutathione (GSH), selenium-dependent glutathione peroxidase activity (RBC-Se-GPx), plasma ubiquinol-10, and α-tocopherol than controls. In a randomly selected group of patients (n = 19), a single HD session caused an additional decrease in RBC-GSH and plasma ubiquinol-10 levels. Plasma thiobarbituric acid reactive substance (TBARS) levels were significantly greater in pre-HD patients than controls. Post-HD plasma TBARS levels were similar to control values. The cohort of +ACEi HD patients had greater pre-HD RBC-GSH content, RBC-Se-GPx activity, and plasma β-carotene concentrations than –ACEi patients (RBC-GSH: +ACEi, 3.1 ± 0.9 μmol/mL packed RBCs [PRBCs]; –ACEi, 1.2 ± 0.3 μmol/mL PRBCs [P < 0.05 v +ACEi]; RBC-Se-GPx: +ACEi, 5.8 ± 0.7 U/mL PRBCs; –ACEi, 4.3 ± 0.2 U/mL PRBCs [P < 0.05 v +ACEi]; plasma β-carotene: +ACEi, 0.54 ± 0.16 μmol/L plasma; –ACEi, 0.19 ± 0.05 μmol/L plasma [P < 0.05 v +ACEi]). Results show profound alterations in the circulating antioxidant systems of chronic HD patients and that additional oxidative stress occurs during the HD procedure. In addition, in +ACEi HD patients, the levels of several antioxidant defenses are greater than in those in –ACEi HD patients.