Acoustic and electrical hearing after Atoh1 treatment

描述(由申请人提供)：我们最近证明，在基因治疗后，哺乳动物的Corti器官中产生了新的内毛细胞(IHC)。具体地说，实验涉及将带有Atoh1基因插入片段(Ad.Atoh1)的腺病毒载体体内接种到成熟的预聋豚鼠耳蜗中。我们还证明了新的毛细胞可以吸引神经元。用Atoh1治疗的预聋耳朵表现出由Preyer反射和听觉诱发的听性脑干反应(ABR)阈值确定的部分功能恢复。在目前的应用中，我们建议使用动物心理物理学技术和生理测量来定义恢复的声学听力的性质和范围。我们还将进行与使用这种Atoh1疗法与人工耳蜗术相结合的相关实验。对于前两个特定目标，我们将用耳毒性药物致聋豚鼠，用Atohl1治疗，并测量心理物理检测(目标1)和辨别力(目标2)以及ABR和失真产物耳声发射(DPOAE)。在目标3中，我们将评估Ad.Atoh1接种、人工耳蜗植入和人工耳蜗电刺激之间的相互作用。在目标4中，我们将在接种的耳朵中植入人工耳蜗，并评估在有和没有恢复IHC的情况下，对电刺激和电诱发复合动作电位(ECAPs)的心理物理反应。一些存活毛细胞的对照(即植入但没有耳聋的动物)将用于与毛细胞恢复的动物进行比较。我们提议的实验涉及使用我们实验室中已经到位的技术。这项工作得到了强劲的初步数据的支持，代表了相对低风险和非常高影响的理想组合。这些实验将加深我们对哺乳动物耳蜗毛细胞再生的功能意义的理解，并有助于开发一种临床治疗感音神经性耳聋的方法，包括人工耳蜗术和细胞替代疗法的联合使用。

DESCRIPTION (provided by applicant): We have recently demonstrated that new inner hair cells (IHCs) are generated in the mammalian organ of Corti following gene therapy. Specifically, the experiments involve in vivo inoculation of an adenovirus vector with the Atoh1 gene insert (Ad.Atoh1) into the mature predeafened guinea pig cochlea. We have also demonstrated that the new hair cells can attract neurons. Predeafened ears treated with Atoh1 exhibit partial restoration of function as determined by Preyer's reflex and acoustically-evoked auditory brainstem response (ABR) thresholds. In the current application we propose to use animal- psychophysics techniques and physiological measures to define the nature and extent of the restored acoustic hearing. We will also conduct experiments relevant to the use of this Atoh1 therapy in conjunction with cochlear implants. For the first two specific aims we will deafen guinea pigs with ototoxic drugs, treat them with Atohl1 and measure psychophysical detection (Aim 1) and discrimination (Aim 2) as well as ABRs and distortion product otoacoustic emissions (DPOAEs). In Aim 3, we will assess the interaction between Ad.Atoh1 inoculation, cochlear implantation, and electrical stimulation of the cochlear implant. In Aim 4 we will place a cochlear implant in the inoculated ear and assess psychophysical responses to electrical stimulation and electrically evoked compound action potentials (ECAPs) with and without restored IHCs. Controls with some surviving hair cells (i.e., animals that are implanted but not predeafened) will be used for comparison to animals with restored hair cells. The experiments we propose involve the use of techniques that are already in place in our laboratories. The work is backed by strong preliminary data, and represents an ideal combination of relatively low-risk with very high impact. The proposed experiments will enhance our understanding of the functional significance of hair cell regeneration in the mammalian cochlea and contribute to the development of a clinical therapy for sensorineural deafness involving the combined use of cochlear implantation with cell replacement therapy.