Clin Chem Lab Med 2005;43(4):383–388  2005 by Walter de Gruyter • Berlin • New York. DOI 10.1515/CCLM.2005.069 2005/181 Article in press - uncorrected proof The effect of antioxidant supplementation on superoxide dismutase activity, Cu and Zn levels, and total antioxidant status in erythrocytes of patients with Graves’ disease Vesna Bacic-Vrca 1, *, Franjo Skreb 2 , Ivana Cepelak 3 , Ljiljana Mayer 4 , Zvonko Kusic 5 and Blanka Petres 6 1 Department of Clinical Pharmacy, School of Pharmacy and Biochemistry, University of Zagreb, Zagreb, Croatia 2 Department of Nuclear Medicine, Dubrava University Hospital, Zagreb, Croatia 3 Department of Medical Biochemistry and Hematology, School of Pharmacy and Biochemistry, University of Zagreb, Croatia 4 Department of Medical Biochemistry and Hematology, Dubrava University Hospital, Zagreb, Croatia 5 Department of Nuclear Medicine and Oncology, Sestre milosrdnice University Hospital, Zagreb, Croatia 6 Department of Medical Biochemistry, Fran Mihaljevic University Hospital for Infectious Diseases, Zagreb, Croatia Abstract The effects of supplementation with a fixed combi- nation of antioxidants (vitamins C and E, b-carotene and selenium) on superoxide dismutase activity, cop- per and zinc concentrations, and total antioxidant stat- us were monitored in erythrocytes derived from a group of patients with Graves’ disease treated with methimazole, with respect to the rate of achieving euthyroidism. Thyroid-stimulating hormone (TSH), thyroid hormones and the above-mentioned para- meters were measured before therapy, and on days 30 and 60 after therapy initiation. The patients receiving antioxidant supplementation along with methimazole therapy (group A, ns27) achieved euthyroidism at a faster rate than those treated with methimazole alone (group B, ns28). The activity of superoxide dismutase decreased significantly in both patient groups during the treatment; however, there was no significant difference between the groups. There was no significant change in the erythrocyte concentration of copper, whereas the zinc concentra- tion and total antioxidant status showed significant between-group differences. The study results clearly show that antioxidant supplementation in the treat- ment of Graves’ disease is justified, while zinc and *Corresponding author: Vesna Bacic-Vrca, PhD, Department of Clinical Pharmacy, Dubrava University Hospital, Avenija Gojka Suska 6, 10000 Zagreb, Croatia Phone: q385-1-290-3303, Fax: q385-1-286-3695, E-mail: vesnav@kbd.hr total antioxidant status in erythrocytes seem to be sensitive indicators of the efficacy of supplemental therapy. Keywords: antioxidants; copper; Graves’ disease; superoxide dismutase; total antioxidant status; zinc. Introduction Graves’ disease is a hypermetabolic state accompa- nied by an increase in total oxygen consumption, which results in increased formation of reactive oxy- gen species and other free radicals, or in the occur- rence of oxidative stress (1–4). There is ample scientific evidence for the role of oxidative stress in this autoimmune disease, although its trigger remains unknown. In a small number of experimental and clin- ical studies, the existence of oxidative stress in hyper- thyroidism was confirmed by determining different parameters. Some investigators studied changes in the oxidative defense parameters in thyroid gland tissue of hyperthyroid patients (5, 6). Treatment with propylthiouracil (PTU) for 3 months resulted in only partially balanced antioxidative activity compared with a control group (7). Komosinska-Vassev et al. investigated the activity of free radicals and the mech- anisms of antioxidant defense in patients with Graves’ disease during therapy with methimazole. In untreated patients, an increase in lipid peroxidation and in the activity of superoxide dismutase (SOD) and some other cellular antioxidant enzymes were record- ed in comparison with a control group, with simulta- neous lowering of extracellular antioxidant parameters and total antioxidant status (TAS) (8). The disturbed antioxidant defense indicates the possible usefulness of antioxidant supplementation in pre- venting oxidation-induced tissue damage. The favor- able effect of vitamin E supplementation was demonstrated in an experimental animal model of hyperthyroidism (9). Clinical investigations of the effect of particular anti- oxidants in the treatment of Graves’ disease are scarce and results are somewhat contradictory. Seven et al. (10) examined the effect of vitamin C supple- mentation on oxidative stress in hyperthyroid patients treated with PTU. The results showed that the addi- tion of vitamin C strengthened antioxidant defense, with consequential lowering of the degree of oxida- tive stress. On the other hand, a study by Adali et al. (11) on the effect of PTU, propranolol and vitamin E on lipid peroxidation and antioxidant status in patients with hyperthyroidism failed to show any Brought to you by | Tokyo Daigaku Authenticated Download Date | 5/26/15 3:17 AM