Endothelial Dysfunction in Idiopathic Sudden Sensorineural Hearing Loss: A Review.

Nicola Quaranta,Vincenzo De Ceglie,Alessandra D’Elia

doi:10.4081/audiores.2016.151

Abstract

An endothelial dysfunction has been described in idiopathic sudden sensorineural hearing loss (ISSHL) patients. The purpose of our review was to: i) identify, evaluate and review recent research about cardiovascular risk factors involvement and signs of endothelial dysfunction in ISSHL; ii) implication of these discovering in clinical practice and future research. A Medline literature search was conducted to identify any study on the involvement of endothelial dysfunction in ISSHL, published in the English language in the last decade. The following MEDLINE search terms were used: sudden sensorineural hearing loss (SSHL) and endothelial dysfunction (text words). Additional studies were identified by hand searching the references of original articles and review articles. Studies were not excluded on the basis of the qualitative or quantitative definitions of SSHL, treatment regimens, or outcome measures. Data were extracted from included papers by a reviewer. Information on the patients, investigations, methods, interventions, and outcomes were systematically analyzed. Characteristics and results of all included studies were reviewed systematically. High levels of adhesion molecules, hyperhomocysteinemia and lower folate levels, unbalanced oxidative status, a lower value of flow-mediated dilatation of brachial artery and a reduced percentage of circulating endothelial progenitor cells in patients affected by ISSHL support the hypothesis that this syndrome should be considered as a microcirculation disorder based on endothelial dysfunction and drive clinicians to implement all the traditional strategies used for preventing cardiovascular events, to also reduce the likelihood of ISSHL occurrence.

Highlights

Idiopathic sudden sensorineural hearing loss (ISSHL) is defined according to American Academy of Otolaryngology as a hearing loss of at least 30 dB over 3 contiguous test frequencies occurring within a 72h period.[1]
Recent studies have reported that the impaired microvascular perfusion occurring during an ischemic event may be related to traditional vascular risk factors such as hypercholesterolemia, hyperfibrinogenemia, hyperhomocysteinemia and micro embolisms,[11,12] and to oxidative stress which may be synergistically responsible for endothelial damage, especially in terminal microvascular systems.[11,13]
A reduced percentage of circulating endothelial progenitors cells (EPCs) in patients affected by ISSHL support the hypothesis that this syndrome should be considered as a microcirculation disorder and, in author’s opinion, this should drive clinicians to implement all the traditional strategies used for preventing cardiovascular events, to reduce the likelihood of ISSHL occurrence.[23]

Summary

Introduction

Idiopathic sudden sensorineural hearing loss (ISSHL) is defined according to American Academy of Otolaryngology as a hearing loss of at least 30 dB over 3 contiguous test frequencies occurring within a 72h period.[1] It affects 5 to 20 people per 100,000 annually and is characterized by sudden-onset, generally unilateral, sensorineural hearing loss.[2] Its cause is idiopathic in most of the patients; vascular disorders have been proposed as the final common pathway.[3]. It is known that endothelial dysfunction has a prime role in regulating vascular tone by modifying lipoproteins, thrombogenesis and transformation of circulating monocytes into foam cells[10] and that endothelial dysfunction precedes the onset of atherosclerosis

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