Reduced/oxidized glutathione and thiol/disulfide balances in patients with benign paroxysmal positional vertigo

Objective: Benign positional paroxysmal vertigo (BPPV) is the most common cause of vertigo worldwide. Oxidative stress is thought to play a role in the pathophysiology of BPPV. In living organisms, thiol (sulfhydryl, SH) groups have important antioxidant properties as well as many functions. Thiol-disulfide homeostasis systems are important intracellular and extracellular markers of oxidative stress, reflecting antioxidant capacity by thiol levels and oxidative status by disulfide (SS) form. The aim of this study was to compare the intracellular oxidized-reduced glutathione (GSSG-GSH) and extracellular thiol-disulfide (SH-SS) balance parameters of patients diagnosed with BPPV with healthy volunteers. Materials and Methods: This study was designed as a prospective observational study and included patients admitted to hospital with dizziness and diagnosed with BPPV and healthy volunteers (control group). Whole blood and serum samples were collected from all volunteers. The GSSG-GSH balance parameters GSH, Total GSH, GSSG and GSSG/GSH percentage were determined from the whole blood samples and the SH-SS balance parameters SH, Total SH, SS and SS/SH percentage were determined from the serum samples. Results: The study included 43 patients and 43 healthy volunteers. No significant difference was found between the patient group and the control group in terms of age and gender. (p > 0.05). Antioxidant parameter levels (GSH, SH) were lower in the patient group compared to the control group, whereas oxidant parameter levels (GSSG, SS) and oxidant/antioxidant ratios (GSSG/GSH, SS/SH) were higher in the patient group compared to the control group (p < 0.05 for all). Conclusion: In this study, intracellular GSSG-GSH and extracellular SH-SS balance parameters were found to be shifted towards oxidized forms in patients with BPPV, suggesting that oxidative stress is involved in the pathophysiology of BPPV. Keywords: BPPV, oxidative stress, thiol, disulfide, glutathione