Evaluation of oxidative stress in patients with euthyroidism and with subclinical hypothyroidism

Objective: There is not sufficient data about oxidative stress in euthyroid Hashimoto (EH) and subclinical hypothyroid Hashimoto (SHH) disease . We studied oxidative stress with more oxidative stress tests in EH and SHH patients and assessed whether there is an association betweeen Hashimoto disease and PON1 phenotype.Materials and Method: 35 EH and SHH patients and 38 control was included to the study. Comprehensive biochemistry, routine blood analysis, total antioxidant status (TAS), total oxidant status (TOS), oxidative stress index (OSI), arilesterase (ARE) paraxonase (PON), lipid hidroperoxide (LOOHs) were measured, and PON1 phenotype was determinated.Result: The levels of TOS and OSI increased significantly in patients with EH and SHH when compared with the control group (for TOS p = 0.005, p = 0.004; for OSI p = <0.001, p = <0.001, respectively). The level of ARE activity increased closely significant in patients with EH, and increase significantly in patients SSH patients when compared with the control group (p = 0.059, p = 0.024 respectively). The levels of PON, TAS, LOOHs are similar in the control group. Hashimoto's patients also have found that PON1 phenotype distribution similar to the control group (p: 0,303).Conclusion: TOS, OSI and ARE were found to be increased in EH patients; however TAS, paraoxonase and LOOHs were similar to the control group. Increased OSI is related to increase in TOS in Hashimoto patients, because TAS was found to be similar to the controls. In EH and SHH patients, ARE activity, which is an indicator of molecular concentration of PON 1 enzyme, was found to be increased. On the other hand paraoxonase activity was similar to the control group, due to its consumption during the process of reducing the elevated LOOHs as a result of the increase in TOS. Consequently lipid peroxidation was found to be at a similar level with the controls. Oxidative stress parameters and biochemical values are similar in EH and SHH patients. In the PON1 phenotyping we performed, no PON1 phenotype creating predisposition to Hashimoto disease was detected.