Recent Advances in Understanding Aminoglycoside Ototoxicity and Its Prevention

Abstract

Studies over the last decade have left little doubt that reactive oxygen species (ROS) participate in the cellular events leading to aminoglycoside-induced hearing loss. The evidence ranges from the demonstration of aminoglycoside-mediated ROS formation in vitro to the prevention of ototoxicity by antioxidants in guinea pig in vivo. Here we review a hypothesis of the mechanism of toxicity, discuss possible causes underlying the gradient in base-to-apex sensitivity of outer hair cells, and present recent results on the adult mouse as a new animal model of aminoglycoside ototoxicity and its prevention.

The importance of audiometric monitoring in patients with multidrug-resistant tuberculosis

“…Some phonemes such as [s], [f], and [t] have low intensities, such that any loss in high frequencies can hinder their perception 5,9 . Difficulty hearing but not understanding what is being said can cause embarrassment and lead to social isolation, often with occupational consequences 5 .…”

“…Difficulty hearing but not understanding what is being said can cause embarrassment and lead to social isolation, often with occupational consequences 5 . Because of this, it is essential to carefully consider patient complaints of hearing loss or difficulty understanding speech.…”

“…Dizziness is a vestibular complaint defined as an illusory sense of rotation associated with impaired perception of mobile environments 5 . Damage to the hair cells of the vestibular system (the bulb and otolith organs) can activate the reflex responses generated by head, eye, and body movements triggering dizziness 5,9,15 .…”

“…These agents are cost-effective and widely used in lowand middle-income countries 2,3 . Yet, aminoglycoside use for the treatment of MDR-TB is associated with ototoxicity in 5-64% in cases [3][4][5][6][7][8][9][10][11] . Ototoxicity can produce hearing loss and associated psychosocial changes that negatively affect quality of life 12 .…”

Cochlear function in mice following inhalation of brevetoxin-3

“…It has long been known that mice are vulnerable to an aminoglycoside-induced hearing loss only during their pre-adult stage of development (Henry et al 1981). Recently, Schacht and his coworkers (Wu et al 2001(Wu et al , 2002 attempted to determine the appropriate dosing variables for gentamicin ototoxicity in mature mice, using a series of different drug concentrations. However, mice succumbed to the systemic toxicity of the drug before a measurable hearing loss could be obtained.…”