Endocrine Abstracts

Background: Oxidative stress is involved in the pathogenesis of Graves hyperthyroidism (GH) and a disbalance of the cell redox state is associated with thyroid hyperfunction and the reccurence of the disease.

Aim: To study the level of reactive oxygen species (ROS) and NAD(P)-dependent dehydrogenases of peripheral blood neutrophils in patients with compensated and relapse GH ongoing thiamazole.

Materials and Methods: The study included 96 women with onset of Graves’ disease, aged 20 to 65 years, ongoing thiamazole. At the follow-up examination three months after the start of thiamazole all patients divided into two groups, respectively, compensated and relapse hyperthyroidism. The level of ROS was studied using a 36-channel chemiluminescence analyzer "BLM-3607" and characterized by: Tmax – the rate of chemiluminescent reaction, Imax - the maximum level ROS synthesis and the area under the chemiluminescence curve (S - total synthesis of ROS for 90 minutes). The activity of NAD(P)-dependent dehydrogenases in neutrophils was determined using the bioluminescent method.

Results: In relapse GH patients, the indicator S of spontaneous and zymosan-induced lucigenin-dependent chemiluminescence increases significantly, both relative to the control and to the values of GH compensated patients (P< 0,001). Luminol-dependent chemiluminescence in GH relapsed patients demonstrated more than tenfold increase of S relative to the control, but no statistically significant differences were found in GH compensated patients. In GH patients both groups the activity of the studied NAD-dependent oxidoreductases (NAD-GDH and MDH), auxiliary dehydrogenase reactions (NADP-GDH and NADP-ICDG) and NADH-dependent reactions (NADH-LDH and NADH-MDG) is increased (P< 0,001). A high level of NADH-dependent glutamate dehydrogenase was observed in GH relapse patients, both relative to the control and GH compensated patients (P< 0,001). In GH compensated patients compared to control the low activity of Lactate dehydrogenase was revealed (P< 0,001). In GH relapse patients the levels of G6PDH and NADP-GDH activity are correlated with S spontaneous lucigenin-dependent chemiluminescence (r= 0.74, P< 0.001, in both cases) and Imax spontaneous luminol-dependent chemiluminescence (r= 0.69, P= 0.003 and r= 0.65, P= 0.005, respectively).

Conclusion: In GH compensated patients the level of oxidative stress mainly affects the primary ROS production, which is associated with hyperthyroidism compensation and the immunosuppressive effect of thiamazole. In GH relapse patients, there are more changes in the production of secondary ROS, indicating the activation of cellular response immunological mechanisms, that determined by the features of intracellular metabolism and may play an important role in the recurrence of the disease.