Dissecting the Circadian Clock and Toll-Like Receptor Gene Alterations in Ménière's Disease and Vestibular Migraine

Introduction: Meniere’s disease (MD) and Vestibular migraine (VM) are common causes of recurrent dizziness and vertigo in the otologic clinic. They share symptoms such as fluctuating hearing loss, ear fullness, and tinnitus, making differential diagnosis challenging. Therefore, it is sometimes difficult to differentiate these two entities in the clinic practice. Common triggers like sleep disturbances and infections could influence the circadian clock and Toll-like receptor (TLR) gene expression. This study investigates the Circadian Clock and Toll-like Receptor Gene alterations in MD and VM.

Methods: Peripheral blood leukocytes from 33 MD patients, 14 VM patients, and 27 healthy controls were analyzed. We examined the expression of 9 circadian clock genes and 6 TLR genes using quantitative reverse transcriptase-polymerase chain reaction (qRT-PCR).

Results: Sleep quality, assessed through questionnaires, was significantly poorer in MD and VM patients compared to healthy controls, with no notable difference between MD and VM. qRT-PCR revealed lower PER1 expression in both VM and MD patients compared to controls, though the difference was not significant between VM and MD. Notably, TLR9 expression was higher in MD patients than in VM patients and healthy controls.

Conclusions: Our study indicates that sleep disturbance and circadian clock gene expression do not distinguish MD from VM. However, the elevated expression of the TLR9 gene in MD patients suggests that innate immune responses might play a role in the pathogenesis of MD.