Optimization of treatment flow to improve performance of retinal gene therapy

视网膜基因治疗是治疗遗传性视网膜变性的一种新工具。来自世界各地包括我们自己在内的几个小组的临床前研究清楚地表明，这种方法有望为这类潜在的致盲疾病提供治愈方法。在从长凳到床边相对较快的进展之后，在过去不久已经开始了几项临床研究，进一步的人体试验正在准备中。虽然传统上这一领域的重点是扩大治疗适应症和媒介开发，但优化治疗流程的机会充其量也只是得到了适度的关注。然而，我们相信，通过这种方式，可以在疗效和疗效寿命方面取得相当大的改善。治疗的关键和关键部分是视网膜下注射。一般认为，视网膜和RPE在注射时分离，在水泡溶解后再次结合，这被观察到需要几个小时到几天的时间。然而，据我们所知，没有关于可能影响注射的最佳体积、气泡大小/局部压力特征、一天中最佳时间/与昼夜节律一致的参数的全面数据。在小鼠模型中，我们使用过去几年开发的标准化方案在这方面进行了初步研究。我们发现，视网膜下注射部位的形态超微结构比之前想象的要严重得多。特别是，我们发现视网膜下注射有规律地破裂光感受器外部节段，而不是将它们拉出视网膜/RPE界面。基于我们的初步数据，我们进一步进行了一项试点研究，试图优化注射的时间点。特别是，我们的目标是利用假定的RPE/视网膜键的机械波动，据称这种波动在视盘脱落时最小。事实上，我们发现，在预期的椎间盘脱落时间注射比12小时后注射产生的损害要小得多。在这项建议中，我们探索通过与昼夜节律的最佳同步来改进治疗程序的选项，以便为给定的治疗实现更好的结果。除了对形态学的急性影响外，我们还将研究人类遗传性视网膜变性疾病模型的长期结果，并评估观察到的有利效果是否依赖于视杆或视锥。随着最近在活体人眼中观察到光感受器盘脱落，昼夜节律同步治疗将很快在临床环境中成为可能。

Gene therapy of the retina is a novel tool for the treatment of inherited retinal degenerations. Preclinical studies from several groups world-wide including our own clearly show the promise of this approach to provide a cure for this potentially blinding group of diseases. Following a relatively fast advancement from bench to bedside, several clinical studies have been started in the immediate past and further human trials are in preparation. While traditionally the focus in this field is on the expansion of therapeutic indications and vector development, opportunities for the optimization of treatment flow have at best received moderate attention. We believe, however, that quite substantial improvements in the efficacy and longevity of curative effects may be accomplished this way. A key, seminal part of the treatment is the subretinal injection. The general believe is that retina and RPE separate at the time of the injection and come together again after the bleb has resolved, which has been observed to take hours to a few days. However, there is to our best knowledge no comprehensive data on presumably influential parameters like best volume for injections, size of bleb/local pressure characteristics, and optimal time of day/conformance with circadian rhythm. In murine models, we have conducted preliminary studies in this regard using a standardized protocol developed over the past years. We found that the morphological ultrastructure at the subretinal injection site was much more compromised than previously thought. In particular, we found that subretinal injections regularly rupture photoreceptor outer segments instead of pulling them out of the retina/RPE interface. Based on our preliminary data, we further conducted a pilot study in an attempt to optimize the time point for injections. In particular, we aimed to take advantage of presumed mechanical fluctuations in RPE/retina bonds, which allegedly are minimal at the time of disc shedding. Indeed, we found that injections at the expected time of disc shedding produced considerable less damage than those 12h later. In this proposal, we explore options to improve the treatment procedure via an optimal synchronization with the circadian rhythm in order to achieve a superior outcome for a given therapy. Besides acute effects on morphology, we will study the long-term outcome in disease models for human inherited retinal degenerations, and assess whether the favorable effect observed is dependent on rod or cone vision. As the observation of photoreceptor disc shedding in the living human eye has recently been demonstrated, a circadian rhythm-synchronized treatment will certainly become possible soon in a clinical setting.