Investigating the role of Sirt1-modulated oxidative stress in relation to benign paroxysmal positional vertigo and Parkinson's disease.

Benign paroxysmal positional vertigo (BPPV) is one of the most frequently encountered primary complaints in dizziness clinics. The incidence of BPPV has been proven to increase with age. The relationship between BPPV and another neurodegenerative disease, Parkinson's disease (PD), has not been previously discussed. This study aimed to investigate the relationship of BPPV and PD with oxidative stress. A total of 30,811 subjects participated in our cohort study. The study cohort comprised 5057 BPPV patients and a comparison cohort of 25,754 nonBPPV patients. SIRT1 axis gene expression was investigated in BPPV patient blood samples and a PD cell model of 6-hydroxydopamine (6-OHDA)-treated PC-12 cells to elucidate the potential in vitro and in vivo mechanisms of degeneration in PD and BPPV. Our data suggest that BPPV patients with histories of head injuries show a significantly higher hazard to develop subsequent PD (hazard ratio, 3.942; confidence interval, 1.523-10.205, p = 0.005). We also observed that oxidative status is increased in blood samples from patients with BPPV. Our in vitro study suggests that SIRT1 function is inhibited by oxidative stress, which thereby promotes 6-hydroxydopamine-induced cell death. We conclude that BPPV is independently associated with an increased risk of PD. This finding may be attributed to oxidative stress-mediated inhibition of SIRT1 expression levels.