Oxidative status in patients with benign paroxysmal positional vertigo Small Title: Oxidative stress and BPPV

Abstract

UNCORRECTED Original Article INTRODUCTIONBenign paroxysmal positional vertigo (BPPV) is the most frequently peripheral vestibular disorder, especially in older patients suffering from vertigo [1] . The brief vertigo attacks and imbalance symptomatic of BPPV are caused by otoconia freely floating within the semicircular canals [2] . Vertigo occurs after specific head movements and has the characteristics of nystagmus, including with respect to latency time, fatigability and transiency. Canalithiasis [3] and cupulolithiasis [4] are the most probable mechanisms underlying BPPV. Although any of the three semicircular canals may be involved, canalithiasis of the posterior semicircular canal is the underlying cause in at least 85% of patients [5] .Oxidative stress, defined as excess production of reactive oxygen species (ROS) that is not counterbalanced by adequate endogenous and exogenous antioxidant defenses, causes cellular dysfunction and is a risk factor for microvascular injury [6] . Several studies have shown an elevation of oxidative stress levels in different pathologies, with higher than control levels of biomarkers such as modified lipids, proteins, and nucleic acids, reductions in antioxidant capacity, and increased ROS production by leukocytes. In otolaryngology practice, the relationship between oxidative stress and laryngeal cancer, hearing loss, rhinosinusitis, otitis media, chronic tonsillitis, and other conditions has been investigated [7][8][9][10] . In a recent study, it was revealed that calcium metabolism and its relationship with oxidative stress may play a role in the development of BPPV [7] .The aim of this prospective study was to evaluate the role of oxidative stress, using thiol/disulfide homeostasis as a novel indicator, in the etiology of BPPV.Oxidative status in patients with benign paroxysmal positional vertigo OBJECTIVE: Benign paroxysmal positional vertigo (BPPV) is the most frequently peripheral vestibular disorder, especially in older patients suffering from vertigo. The brief vertigo attacks and imbalance symptoms of BPPV are caused by freely floating otoconia within the semicircular canals. The aim of this prospective study was to evaluate the role of oxidative stress, using native thiol/disulfide (SH/SS) homeostasis as a novel indicator, in the etiology of BPPV. MATERIALS and METHODS:The 62 participants in the study included 31 patients with BPPV and, as the control group, 31 healthy individuals without any cochleovestibular disorders. RESULTS:Patients with BPPV initially had significantly lower native SH levels and significantly lower SH/total thiol (TT) ratios, as well as significantly higher SS/SH and SS/TT ratios than the control group. After successful treatment of their vertigo, confirmed based on the results of the second blood sample, BPPV patients still had lower SH levels, and SH/TT ratios, and significantly higher SS/SH and SS/TT ratios compared with the control group. CONCLUSION:Our results suggest a role for oxidative stress in the development of BPPV, through both c...