To compare the cochlear distribution of low-dose fluorescent gentamicin after intra-tympanic administration in guinea pig (GPs) with clinical data of low dose intra-tympanic gentamicin in patients with intractable vertigo.
Purified gentamicin-Texas Red (GTTR) was injected intratympanically into GPs and the cochlear distribution and time course of GTTR fluorescence in outer hair cells (OHCs) was determined using confocal microscopy.
GTTR was rapidly taken up by OHCs, particularly in the subcuticular zone. GTTR was distributed in the cochlea in a decreasing baso-apical gradient, and was retained within OHCs without significant decrease in fluorescence until 4 weeks after injection.
OHCs rapidly take up GTTR after intra-tympanic administration with slow clearance.
A modified low-dose titration intratympanic approach was applied to patients with intractable Ménière's Disease (MD) based on our animal data and the clinical outcome was followed. After the modified intratympanic injections for MD patients, vertigo control was achieved in 89% patients, with hearing deterioration identified in 16% patients. The 3-week interval titration injection technique thereby had a relatively high vertigo control rate with a low risk of hearing loss, and is a viable alternative to other intratympanic injection protocols.
*Department of Otology and Skull Base Surgery, Eye Ear Nose and Throat Hospital; †Institutes of Brain Science, Fudan University, Shanghai, China; and ‡Oregon Hearing Research Center, Oregon Health and Science University, Portland, Oregon, U.S.A.
Address correspondence and reprint requests to Chun-Fu Dai, M.D., Ph.D., Department of Otology and Skull Base Surgery, Eye Ear Nose and Throat Hospital, Fudan University, 83 Fenyang Road, Shanghai 200031, China; E-mail: email@example.com
This study was supported by Science and Technology Ministry of China "Tenth Five" Tackling Key Project Fund (No. 2004BA702B04 [C. F. D.]), Educational Ministry of China (NCET-06-0369 [C. F. D.]), National Natural Science Foundation (Nos. 30772398 [C. F. D.] and 30600704 [J. P. L.]), and National Institute on Deafness and Other Communication Disorders (DC004555 [P. S. S.]).
F. Z. and J. P. L. made equal contribution to this study.