Radical scavengers: A remedy for presbyacusis. A pilot study

Abstract

In this study, geranylgeranylacetone (GGA) was shown to induce heat shock protein (HSP)70 in the vestibular end organs of the guinea pig and to alleviate gentamicin (GM) ototoxicity. This was accomplished without thermal preconditioning. In isolated guinea pig vestibular end organs we demonstrated possible prophylactic (preventive) effects of GGA on GM ototoxicity by actively inducing HSP70. When HSP70 was pre-incubated with GGA, its content in sensory cell cytoplasm and transitional dark cells was increased. Pre-incubation of vestibular end organs with GGA gave sensory cells partial protection from GM toxicity. These findings show that administration of GGA can protect vestibular sensory cells from GM ototoxicity and suggest that induction of HSP70 by GGA may be a useful adjunct for the treatment of vestibular disorders.

Dietary antioxidant intake is associated with the prevalence but not incidence of age-related hearing loss

“…Given the free radical scavenging properties of vitamin E it is not surprising that it has been shown to reduce inner ear damage in an animal model (1). Additionally, vitamin E has been used to tread idiopathic sudden hearing loss, with acceptable results (3,20). Moreover, this protective influence of vitamin E on hearing function was observed among older adults with low vitamin C intake.…”

“…It is this generalized hypoperfusion that leads to the generation of reactive oxygen metabolites (ROM), which may cause cochlear damage (1,5). Several animal studies have demonstrated the otoprotective effects of free radical scavengers and the antioxidant properties of vitamins C and E, and beta carotene have been shown to protect from inner ear damage caused by aging, noise exposure, acoustic trauma, aminoglycosides, and cisplatin (3,5,6). In a 16-week human trial, daily vitamin C supplementation (600 mg/d) in 23 individuals with age-related hearing loss resulted in an average of 3.8 dB audiometric threshold improvement in hearing sensitivity (p <0.01) (3).…”

“…Several animal studies have demonstrated the otoprotective effects of free radical scavengers and the antioxidant properties of vitamins C and E, and beta carotene have been shown to protect from inner ear damage caused by aging, noise exposure, acoustic trauma, aminoglycosides, and cisplatin (3,5,6). In a 16-week human trial, daily vitamin C supplementation (600 mg/d) in 23 individuals with age-related hearing loss resulted in an average of 3.8 dB audiometric threshold improvement in hearing sensitivity (p <0.01) (3). In contrast, a recent prospective study of 3559 cases of hearing loss showed that higher intake of vitamin C, E and beta carotene did not reduce the risk of hearing loss in men aged 40-74 years (5).…”

“…Aside from biological degeneration resulting from the aging process itself, genetic risk factors, exposure to noise or toxic substances, and the occurrence of certain diseases may predispose individuals to age-related hearing loss (2). The greatly improved knowledge regarding the etiology, symptoms and epidemiology of age-related hearing loss has not been matched by our ability to successfully alleviate its detrimental consequences (3).…”

The role of mitochondrial oxidative stress in hearing loss

“…Accumulating evidence demonstrated that antioxidants and free radical scavengers may serve as effective therapeutic agents to block the activation of death mechanisms induced by Ros overproduction, including the auditory system [62]. Therapy for hearing loss mediated by ROS overproduction is most likely to be successful during the early stages of disease progression, when structural damage and hair cell loss is limited.…”