Section on Epithelial and Retinal Physiology and Disease, National Eye Institute, Bethesda, MD, USA.
Laboratory of Retinal Cell and Molecular Biology, National Eye Institute, Bethesda, MD, USA.
Adv Exp Med Biol. 2018;1074:633-640. doi: 10.1007/978-3-319-75402-4_77.
Previous work suggests that replacing diseased Retinal Pigment Epithelium (RPE) with a healthy autologous RPE sheet can provide vision rescue for AMD patients. We differentiated iPSCs into RPE using a directed differentiation protocol. RPE cells at the immature RPE stage were purified and seeded onto either electrospun poly(lactic-co-glycolic acid) (PLGA) scaffolds or non-biodegradable polyester cell culture inserts and compared the two tissues. In vitro, PLGA and polyester substrates produced functionally similar results. Following in vitro evaluation, we tested RPE tissue in animal models for safety and function. Safety studies were conducted in RNU rats using an injection composed of intact cells and homogenized scaffolds. To assess function and develop surgical procedures, the tissues were implanted into an acute RPE injury model pig eye and evaluated using optical coherence tomography (OCT), multifocal ERG (mfERG), and histology. Subretinal injection studies in rats demonstrated safety of the implant. Biodegradability and biocompatibility data from a pig model demonstrated that PLGA scaffold is safe, with the added benefit of being resorbed by the body over time, leaving no foreign material in the eye. We confirmed that biodegradable substrates provide suitable support for RPE maturation and transplantation.
先前的工作表明，用健康的自体 RPE 片替换患病的视网膜色素上皮（RPE）可为 AMD 患者提供视力挽救。我们使用定向分化方案将 iPSC 分化为 RPE。将处于未成熟 RPE 阶段的 RPE 细胞纯化并接种到电纺聚（乳酸-共-乙醇酸）（PLGA）支架或不可生物降解的聚酯细胞培养插入物上，并比较了这两种组织。在体外，PLGA 和聚酯基质产生了功能相似的结果。在体外评估之后，我们在动物模型中测试了 RPE 组织的安全性和功能。使用由完整细胞和均质支架组成的注射剂在 RNU 大鼠中进行安全性研究。为了评估功能并开发手术程序，将组织植入急性 RPE 损伤模型猪眼，并使用光学相干断层扫描（OCT）、多焦 ERG（mfERG）和组织学进行评估。在大鼠中的眼内注射研究表明了植入物的安全性。来自猪模型的可生物降解性和生物相容性数据表明，PLGA 支架是安全的，随着时间的推移被身体吸收，眼内没有留下任何异物。我们证实可生物降解的基质为 RPE 成熟和移植提供了合适的支持。
