MiR-431 Target Action Eya4 Cochlear Function In Gene Regulation And Bilateral Atresia Baha Patient Outcomes Analysis

Part One Basic Research miR-431Involves in Regulating Cochlear Function by Targeting Eya4Objective To study the function of miR-431in cochleae in order to understand the relationship between microRNAs and hearing loss, and help clarify the cause of hereditary deafness. To provide the theoretical basis for prevention and treatment of hereditary deafness in the future.Methods We investigated the spatial-temporal expression profiles of miR-431in cochleae of mice using Real-time PCR and miRNA in situ hybridization. miR-431Transgenic(Tg) mice were established andauditorybrainstemresponses (ABRs) were detected to examine whether there was a difference of hearing ability between the Tg and Wt mice. We also used surface preparation technique of cochlear basilar membrane and cochlear sections to investigate the structural changes in the cochleae of Tg mice. We used bioinformatics softwares to predict the target mRNA of miR-431and confirmed the directinteractionbetweenmiR-431and the3’UTRof Eya4mRNA by luciferasereporterassay. Stable over-expression of miR-431wasachieved in PC12cells and the primary spiral ganglion neurons(SGN) of new born mice were cultured. Experiments in vitro further verified the inhibiting effects of miR-431in neurons.Results miR-431were highly expressed in SGN, Corti organ and striavascularis in cochleae of the new born mice and the expression were gradually reduced along with the developement. ABRs were detected in the Tg and Wt mice of A line and B line. The ABR thresholds were significantly higher in Tg mice compared to Wt mice. Few hair cells were missing in basal membrane of cochleae of Tg mice, and SGNs were sparse in Rosenthal canals of Tg mice. The density of SGNs of Tg mice was significantly lower than that of Wt mice. Eya4was confirmed as the target gene of miR-431by luciferasereporterassay and the EYA4content detected in cochleae of Tg mice was lower compared to Wt mice. The differentiation was inhibited in PC12cells in which miR-431were stably over-expressed. The proportion of mature neurons and the length of axons was also less in SGN primary culture of cochleae of miR-431Tg mice.Conclusion Over-expression of miR-431in cochleae of mice could result in hearing loss. Excessive miR-431inhibited the translation of its target mRNA-Eya4, leading to down regulation of EYA4protein. The deficiency of EYA4may be the reason of sparse SGNs in cochleae of Tg mice. Part Two Clinical Research The Efficacy of Bone-Anchored Hearing Adis in Patients With Congenital Bilateral Aural AtresiaObjective To evaluate the efficacy and satisfaction of bone-anchored hearing aids (Bahas) in patients with bilateral aural atresia. And to discuss the prevention and treatment of postoperative complications.Methods Baha was implanted during auricle reconstruction surgery, or after the auricle was rebuilt. Mean pure-tone threshold and speech audiometry test using Mandarin Speech Test Materials (MSTM) and results were compared among patients unaided and with Baha. Scores from the Baha user questionnaire and Glasgow Children’s Benefit Inventory (GCBI) were used to measure patient satisfaction and subjective health benefit. Retrospective analysis of16patients underwent Baha implantation were conducted to summarize the complications and treatment.Results The mean speech discrimination scores measured in a sound field with a presentation level of45dB HL were6.7±7.4%unaided and86.5±4.4%with Baha. Scores with a presentation level of65dB HL were56.5±7.4%unaided and90.1±3.4%with Baha. The unaided speech reception threshold was60.6±7.5dB HL and24.7±5.0dB HL with Baha. The mean pure-tone threshold of the patients was61.6±7.8dB HL unaided and23.8±5.9dB HL with Baha. The Baha application questionnaire demonstrated excellent patient satisfaction. The average benefit score of GCBI was45.6±14.4. Five patients suffered from skin complications. Patients had a Holgers Grade1-2skin reaction were cured by local application of antibiotics; and the patients experienced Holgers Grade3skin reaction were taken revision surgeries for excessive soft tissue growth. One patient replaced the Baha abutment with a longer9.0mm one.Conclusion The implanted Baha has been one of the most reliable methods of auditory rehabilitation for patients with bilateral aural atresia. It can improve the patient’s speech recognition performance and the quality of life. Infection and skin overgrowth around the abutment was the most common complications of Baha implantation.