Hearing Thresholds and Serum Apelin Levels in Patients with Vertebrobasilar Insufficiency

Abstract

Introduction The vertebral artery arises from the subclavian artery, passes through the foramina transversaria of the cervical vertebrae, and extends upward. It unites with the contralateral vertebral artery at the lower border of the pons and forms the basilar artery. The posterior 1/3 region of the brain is supplied with blood by these vessels called the vertebrobasilar system. Vertebrobasilar insufficiency (VBI) is a clinical entity resulting from decreased flow volume due to hemodynamic changes in this artery and its branches. The symptoms of VBI include ataxia, focal neurologic signs, or dysarthria according to the region where ischemia occurs. Similarly, peripheral vertigo, positional nystagmus, and hearing loss can be found in patients as the reason of cocleo-vestibular system dysfunction. The diagnosis of VBI should be confirmed with imaging techniques, and doppler ultrasonography (US) is frequently used for this aim. Moreover, angiography, magnetic resonance imaging, magnetic resonance angiography, and computed tomography angiography are used in addition to US (1). Apelin is an adipokine released from the adipose tissue that is accepted to be an endocrine tissue (2, 3). Apelin has been detected in the endothelium of the vessel wall as well as the heart and peripheral organs in the humans (4). Apelin affects angiogenesis and central nervous system and has a role in providing fluid hemostasis and cardiovascular hemodynamics (5). The aim of this study was to determine the hearing thresholds and serum apelin levels of patients with VBI. Considering the possible occurrence of endothelial dysfunction in the basilar artery due to asymmetry of vertebral artery flow volumes while planning the study, it was decided to measure the apelin levels in the serum samples for VBI diagnosis. Thus, the attainability of objective data rather 126