GRAIL gene knockout mice protect against aging-related and noise-induced hearing loss.

BACKGROUND: Hearing loss is a global health issue and its etiopathologies involve complex molecular pathways. The ubiquitin-proteasome system has been reported to be associated with cochlear development and hearing loss. The gene related to anergy in lymphocytes ( GRAIL ), as an E3 ubiquitin ligase, has not, as yet, been examined in aging-related and noise-induced hearing loss mice models. METHODS: This study used wild-type (WT) and GRAIL knockout (KO) mice to examine cochlear hair cells and synaptic ribbons using immunofluorescence staining. The hearing in WT and KO mice was detected using auditory brainstem response. Gene expression patterns were compared using RNA-sequencing to identify potential targets during the pathogenesis of noise-induced hearing loss in WT and KO mice. RESULTS: At the 12-month follow-up, GRAIL KO mice had significantly less elevation in threshold level and immunofluorescence staining showed less loss of outer hair cells and synaptic ribbons in the hook region compared with GRAIL WT mice. At days 1, 14, and 28 after noise exposure, GRAIL KO mice had significantly less elevation in threshold level than WT mice. After noise exposure, GRAIL KO mice showed less loss of outer hair cells in the cochlear hook and basal regions compared with WT mice. Moreover, immunofluorescence staining showed less loss of synaptic ribbons in the hook regions of GRAIL KO mice than of WT mice. RNA-seq analysis results showed significant differences in C-C motif chemokine ligand 19 ( CCL19 ), C-C motif chemokine ligand 21 ( CCL21 ), interleukin 25 ( IL25 ), glutathione peroxidase 6 ( GPX6 ), and nicotinamide adenine dinucleotide phosphate (NADPH) oxidase 1 ( NOX1 ) genes after noise exposure. CONCLUSION: The present data demonstrated that GRAIL deficiency protects against aging-related and noise-induced hearing loss. The mechanism involved needs to be further clarified from the potential association with synaptic modulation, inflammation, and oxidative stress.

Bilateral sudden sensorineural hearing loss in patient with Behçet disease.

Bacckground: Approximately 80% to 85% of sudden sensorineural hearing loss (SSNHL) is idiopathic, but immune-mediated mechanisms are thought to be involved. Behçet disease is an autoinflammatory vasculitis that may involve vessels of the inner ear. It can cause sensorineural hearing loss (SNHL) and an increased risk of SSNHL. Study Sample: We report a 21-year-old man who was diagnosed with Behçet disease in childhood and presented to our clinic with a 10-day history of abrupt hearing deterioration in both ears. Pure-tone audiometry showed severe to profound bilateral SNHL. Results: Oral prednisolone was prescribed for 3 weeks. Concurrent intratympanic steroid injections (ITSIs) were administered in each ear every 2 days for 5 days. A total of 15 daily sessions of hyperbaric oxygen therapy (HBOT) were completed. Acupuncture was performed every 2 days for 1 month. After these combined therapies, the patient's hearing threshold by 20 dB and his speech recognition threshold were improved. Conclusions: Some patients with SSNHL recover no hearing improvement after routine treatment, and alternative treatments including ITSI, HBOT, and acupuncture can be considered as optional. We used an aggressive multimodal approach to treat severe bilateral SSNHL in patient with Behçet disease.

Thyroid Hemiagenesis Accompanying an Ectopic Lingual Thyroid.

Lingual thyroid is an uncommon condition and cases accompanying thyroid hemiagenesis are rarely documented. Patients with thyroid hemiagenesis are usually asymptomatic and generally diagnosed incidentally. Herein, we reported the case of thyroid hemiagenesis accompanying an ectopic lingual thyroid with euthyroidism and presented with regional symptoms.