Neural Stability after Retinal Detachment

描述(申请人提供)：视网膜脱离修复后的视力恢复通常令人失望，超过一半的接受治疗的患者报告低于正常视力。视网膜神经元在脱离后经历了显著的结构可塑性，包括杆状轴突回缩，锥体末端变圆，两极细胞和水平细胞发芽。在动物模型中，其中一些变化发生在视网膜损伤后的几个小时内。有人认为，这种突触重塑导致视力恢复较差。在视网膜细胞培养中，RhoA-Rho激酶(ROCK)信号通路的激活是视杆轴突回缩的主要原因。因此，这一应用验证了一种假设，即RhoA拮抗剂和视网膜手术的联合治疗可能通过防止或减少突触可塑性而显著改善视网膜脱离修复后的视觉结果。这一假说将在成年猪身上进行验证，这些猪的眼睛与人眼相似，主要集中在以下特定目标：1)测试抑制RhoA、ROCK或其底物活性的RhoA拮抗剂是否能防止脱离引起的结构性突触变化，包括杆状轴突收缩、杆-双极突触溶解、锥体末端形态变化和双极细胞萌芽。还将研究RhoA相关药物对胶质细胞反应性的影响；2)确定RhoA相关药物在视网膜脱离后是否可以应用，这是一种更具治疗意义的情景，如果可以，损伤后多长时间；3)确定RhoA相关药物治疗视网膜脱离是否确实有助于复位手术后视觉结构和功能的恢复。形态将通过免疫组织化学、图像分析、激光共聚焦扫描和电子显微镜进行评估。Rho信号的活性水平和时间进程将通过多种成分的生化分析来确定，包括RhoA激活和肌球蛋白轻链磷酸化。复位后的视网膜功能将通过视网膜电图仪进行评估。将接受测试的一些药物(CT-04和Fasudil)已经被批准用于人类使用。如果RhoA拮抗剂被证明是手术再附着的有效辅助药物，我们希望建立在患者身上测试的大致剂量和应用方式。 公共卫生相关性：视网膜脱离修复后的视力结果仍然令人失望，即使在成功的视网膜脱离手术数年后也是如此。在体外，基于阻止有害的光感受器突触改变的有效性，提出了一种治疗视网膜脱离的新方法。该疗法包括眼内应用RhoA拮抗剂结合相对较快的视网膜复位。

DESCRIPTION (provided by applicant): Visual recovery after repair of a retinal detachment is often disappointing with more than half of treated patients reporting below normal visual acuity. Retinal neurons undergo dramatic structural plasticity after detachment including retraction of rod axons, rounding of cone terminals, and sprouting by bipolar and horizontal cells. Some of these changes occur within hours after retinal injury in animal models. It has been suggested that this synaptic remodeling contributes to poor visual recovery. In retinal cell cultures, activation of the RhoA-Rho kinase (ROCK) signaling cascade is primarily responsible for rod axon retraction. Thus, this application tests the hypothesis that a combined therapy of RhoA-antagonists and retinal surgery may significantly improve the visual outcome after repair of a detached retina by preventing or reducing synaptic plasticity. This hypothesis will be tested on adult pigs, whose eyes are similar to human eyes, focusing on the following specific aims: 1) To test whether RhoA antagonists which inhibit the activity of RhoA, ROCK, or their substrates will prevent the structural synaptic changes caused by detachment including rod axon retraction, rod-bipolar synaptic dissolution, cone terminal morphological change, and bipolar cell sprouting. The effect on glial cell reactivity will also be examined; 2) To determine whether RhoA-related drugs can be applied after a detachment, a more therapeutically relevant scenario, and if so, how long after the injury; and 3) To determine if detached retinas treated with RhoA-related drugs indeed help visual structural and functional recovery after reattachment surgery. Morphology will be assessed by immunohistochemistry, image analysis and confocal laser scanning and electron microscopy. Levels of activity and the time-course of Rho signaling will be determined by biochemical assays for multiple components including RhoA activation and myosin light chain phosphorylation. Retinal function after reattachment will be assessed by electroretinograms. Some of the drugs that will be tested (Ct-04 and fasudil) have already been approved for human use. We hope to establish the approximate dosage and mode of application to be tested in patients, if RhoA antagonists prove to be a useful adjunct to surgical reattachment. PUBLIC HEALTH RELEVANCE: Visual outcomes after repair of retinal detachment remain disappointing even years after successful reattachment surgery. Based on the effectiveness of preventing deleterious photoreceptor synaptic change, in vitro, a new therapy is proposed for retinal detachment. The therapy consists of intraocular application of RhoA antagonists combined with relatively rapid retinal reattachment.