Impairment of dynamic thiol-disulphide homeostasis in patients with idiopathic Parkinson's disease and its relationship with clinical stage of disease.

OBJECTIVE: The aim of this study was to investigate dynamic thiol-disulphide homeostasis in patients with idiopathic Parkinson's disease and to determine its relationship with the clinical stage as assessed by the modified Hoehn and Yahr scale.

DESIGN AND METHODS: Fifty-two patients with Parkinson's disease (PD), diagnosed according to the United Kingdom Brain Bank Criteria for idiopathic PD, and 41 healthy individuals were included in the study. Clinical staging of patients was performed according to the Hoehn and Yahr scale. Peripheral blood samples were taken from all participants, and their native thiol and total thiol concentrations were measured using the newly developed automated method. In addition, their amount of disulphide bonds, disulphide/native thiol, disulphide/total thiol and native thiol/total thiol ratios were calculated.

RESULTS: Considering the data obtained from Parkinson's patients and the control group, both native thiol (-SH) and total thiol (-SH+-S-S) levels were found significantly lower in patients with Parkinson's disease. A negative and statistically significant relationship was found between both disease duration and disease stage and native thiol (-SH), total thiol (-SH+-S-S) levels and -SH/(-SH+-S-S-) ratio. A positive and statistically significant relationship was found between both disease duration and stage and -S-S-/-SH and -S-S-/(-SH+-S-S-) ratios.

CONCLUSION: In patients with Parkinson's disease, dynamic thiol-disulphide homeostasis is disrupted, according to disease stage and duration. This balance, easily measured by using the newly developed automated method, can be used in monitoring disease progression. To our knowledge, our study will be the first report in the literature.