Serum levels of heavy metals in patients with Bell's palsy: a case-control study.

PURPOSE: The exact etiology of Bell's palsy (BP) remains unknown, while its potential etiopathology includes neuritis and inflammation-related demyelination as in optic neuritis. It has been reported that disruption of heavy metal homeostasis may be associated with the inflammatory process of optic neuritis; therefore, heavy metals may be involved in the pathogenesis of facial nerve neuritis. In this study, we aimed to investigate serum levels of heavy metals including essential elements [iron (Fe), zinc (Zn), copper (Cu), cobalt (Co), and manganese (Mn)], and nonessential elements [lead (Pb) and cadmium (Cd)] in patients with BP. METHODS: The study included 25 patients with BP and 31 healthy volunteers. For each participant, serum levels of essential and nonessential elements were measured using the atomic absorption spectrophotometer method. RESULTS: Serum levels of essential elements were significantly lower in the patient group compared to the control group (p < 0.001, for each). Serum levels of Pb increased in the patient group compared to the control group although no significant difference was achieved (p = 0.105). In contrast, serum Cd levels increased significantly in the patient group compared to the control group (p < 0.001). CONCLUSION: Our findings suggest that decreased essential and increased nonessential elements may be associated with BP and thus, serum concentrations of these elements should be taken into account in BP. Studies are warranted to determine the role of these elements in treatment of BP.

The relationship between thiol-disulfide balance and idiopathic sudden sensorineural hearing loss.

INTRODUCTION: Impaired cochlear perfusion is a major etiological factor in idiopathic sudden sensorineural hearing loss. Oxidative stress has been shown to be a risk factor for oxidative damage. OBJECTIVES: We investigated the role of oxidative stress in idiopathic sudden sensorineural hearing loss by comparing serum levels of oxidant and antioxidant molecules including thiol/disulfide homeostasis paraoxonase, stimulated thiol/disulfide homeostasis paraoxonase, arylesterase, ceruloplasmin and myeloperoxidase in patients who did and did not recover after treatment. METHODS: The amount of dynamic disulfide was calculated by determining half of the difference between the total thiols and native thiols. After the determination of native, total thiol, and disulfide amounts, the disulfide/total thiol percent ratio, native thiol/total thiol ratio and disulfide/native thiol percent ratio were calculated and then compared between the two groups. Additionally, clinical relationship between audiological recovery and native thiol, disulfide, disulfide/native thiol percent ratio, and disulfide/total thiol percent ratio levels was investigated. Blood samples were also analyzed for the assessment of thiol/disulfide homeostasis paraoxonase, stimulated thiol/disulfide homeostasis paraoxonase, arylesterase, ceruloplasmin, and myeloperoxidase levels. RESULTS: A significant difference was found between the two groups with regard to total oxidant status disulfide, disulfide/native thiol percent ratio, disulfide/total thiol percent ratio, and native thiol/total thiol ratio levels (p =  0.001, p =  0.001, p =  0.001, p =  0.003, p =  0.001, p =  0.002, respectively). However, no significant difference was found between the two groups with regard to thiol/disulfide homeostasis paraoxonase, stimulated thiol/disulfide homeostasis paraoxonase, ceruloplasmin, and myeloperoxidase levels (p >  0.05 for all). CONCLUSION: The results supported the common hypothesis that vascular pathologies are the primary cause of idiopathic sudden sensorineural hearing loss and that other etiological factors ultimately result in vascular pathologies. The oxidant-antioxidant and thiol-disulfide balances were impaired in the idiopathic sudden sensorineural hearing loss group.

Serum levels of oxidative stress indicators and antioxidant enzymes in Bell palsy.

We conducted a prospective study to comparatively evaluate serum levels of malondialdehyde, an oxidative stress indicator, and the antioxidant enzymes glutathione, catalase, and superoxide dismutase in patients with Bell palsy. Our study population was made up of 30 patients with Bell palsy-15 men and 15 women, aged 25 to 68 years (mean: 50.4)-who were seen in the Department of Otorhinolaryngology at a tertiary care medical center. For comparison purposes, we recruited 26 healthy age- and sex-matched controls-16 men and 10 women, aged 40 to 67 years (mean: 54.3). Serum samples were obtained from all participants before the initiation of steroid treatment to the Bell palsy patients. A correlation was sought between demographic data and serum levels of malondialdehyde, glutathione, catalase, and superoxide dismutase. We found that the serum level of malondialdehyde was significantly higher in the Bell palsy group and that the levels of glutathione, catalase, and superoxide dismutase were all significantly lower (p < 0.001 for all comparisons). Correlation analysis revealed that only superoxide dismutase levels were positively correlated with age (r = 0.347, p = 0.009). We suggest that oxidative stress and antioxidant mechanisms may be involved in the pathogenesis of Bell palsy. In this context, serum levels of malondialdehyde, glutathione, catalase, and superoxide dismutase may serve as biomarkers in the diagnosis and follow-up of Bell palsy. Confirmation of the validity, reliability, and reproducibility of these findings necessitates further prospective, randomized clinical trials in larger populations.