Effects of Glucocorticoids on the Inner Ear

Abstract

Hypothesis: Recently, several lines of evidence have suggested that the inner ear is under hormonal control. It is likely that steroids have some influence on the inner ear.Background: Many clinicians have been empirically using steroids for the treatment of diseases associated with endolymphatic hydrops. The theoretical grounds for this are not clear, and there have been a number of debates on the effectiveness of steroid treatment. Furthermore, there are few reports on histological observations of the influences of steroids on the cochlea.Method: Fifteen guinea pigs (30 ears) were divided into three groups. In the control group, physiological saline solution was administered intra-peritoneally for 3 days. In two steroid groups, 40 mg/kg/day of hydrocortisone or 4 mg/kg/day of dexamethasone was administered intra-peritoneally for 3 days. Extension of Reissner's membrane and volume change of the scala media were checked 6 h after the last administration. The degree of Reissner's membrane extension and volumetric change of the scala media were quantitatively measured with the use of a video-digitizer.Results: We did not identify any distinct changes in the cochlea of the control group. In contrast, the extension of Reissner's membrane and endolymphatic hydrops were observed in the animals in the steroid groups. Statistical analysis revealed that Reissner's membrane extended significantly in the steroid groups, and that the volume of the scala media also increased significantly.Conclusion: This is the first report to investigate the effects of systemic administration of glucocorticoids on guineapig cochlea. The extension of Reissner's membrane and dilated endolymphatic space were evident in the steroid groups. However, the underlying mechanism of histological changes was not clear, marked care needs to be taken when administering steroids to patients with Meniere's disease whose histological feature is endolymphatic hydrops.

Dexamethasone for Inner Ear Therapy: Biocompatibility and Bio-Efficacy of Different Dexamethasone Formulations In Vitro

“…To date, the exact mechanisms of sensorineural hearing loss (HL) are still not completely understood [ 3 ] but in preclinical and clinical otology fields, in vitro and in vivo studies and clinical trials are often conducted to seek pharmacotherapies of inner ear disorders [ 4 , 5 , 6 ]. Among these, inflammation-suppressing substances, such as glucocorticoids, and especially dexamethasone, have been widely tested as a potential therapy to treat inner ear pathologies including sudden sensorineural hearing loss (SSNHL) [ 7 , 8 , 9 , 10 ], Menière’s disease [ 11 , 12 , 13 , 14 ], and acute tinnitus [ 15 ]. Additionally, dexamethasone is intensively investigated for its benefit in cochlear implant (CI) patients [ 16 ].…”

Meniere's disease – pathogenesis, diagnosis, non-surgical treatment possibilities and related controversies: review

“…Z kolei nowsze badanie Takeda i wsp., przeprowadzone na świnkach morskich, wykazało, że wstrzyknięcie hydrokortyzonu lub deksametazonu powoduje wydłużenie błony Reissnera i powstanie nieznacznych obrzęków endolimfatycznych, co może wynikać z przyspieszenia homeostazy endolimfy za pośrednictwem AQP3 (kompleksu akwaporyny 3, który reguluje równowagę wody i jonów w płynach ucha wewnętrznego), wzmocnionego glikokortykoidami w uchu wewnętrznym. Według naukowców należy podejść ostrożnie do stosowania sterydów w chorobie Ménière'a ze względu na ich niejasny wpływ na rozwój obrzęku limfatycznego wywołanego przez seryjne podawanie hydrokortyzonu lub deksametazonu, choć właściwie nie wiadomo, ile dawek u człowieka odpowiada 40 mg/kg/dobę hydrokortyzonu i 4 mg/kg/dobę deksametazonu zastosowanym u świnek morskich w badaniu zespołu Takeda [65].…”

Sustained delivery of triamcinolone acetonide from a thermosensitive microemulsion gel system for the treatment of sensorineural hearing loss

“…Due to the reduction in proinflammatory cytokines in cochlear hair cells (Kurabi et al., 2017 ) and modulation of the level of the enzyme Na + /K + -ATPase in the stria vascularis (Curtis et al., 1993 ; Ross et al., 1982 ; Takeda et al., 2020 ), corticoids have been used to treat hearing disorders since the 1950s, and to date, they have been the standard therapy for various forms of hearing loss (including autoimmune inner ear disease, sudden hearing loss, and Meniére’s disease) for over 70 years (Trune & Canlon, 2012 ). The effectiveness of intratympanic corticoid therapy for the treatment of SNHL patients was first reported in 1996 by Silverstein et al.…”