Oxidative stress peripheral parameters in Gravesʹ disease: the effect of methimazole treatment in patients with and without infiltrative ophthalmopathy

Objectives: The study was designed to estimate the influence of hyperthyroidism and antithyroid treatment on oxidative stress peripheral parameters in Gravesʹ disease patients with and without infiltrative ophthalmopathy. Design and methods: Free radical generation and scavenging plasma indices were determined in 47 patients with hyperthyroidism due to Gravesʹ disease (22 with and 25 without infiltrative ophthalmopathy), as well as in 24 healthy volunteers after euthyroidism achievement with methimazole. Results: In the hyperthyroid patients, hydrogen peroxide, lipid hydroperoxides, thiobarbituric acid-reacting substances, ceruloplasmin, superoxide dismutase, and catalase were increased. Glutathione peroxidase and glutathione reductase, however, were reduced. Methimazole treatment resulted in all markers being normalized in the patients without infiltrative ophthalmopathy, yet oxidative stress was still present in the ophthalmopathy group. Conclusion: We suggest that apart from the thyroid metabolic status influence, it is orbital inflammation that triggers changes in blood extracellular indices of reactive oxygen species metabolism.