Department of Medical Research, Taipei Veterans General Hospital, Taipei 11217, Taiwan.
Institute of Pharmacology, School of Medicine, National Yang-Ming University, Taipei 11217, Taiwan.
Int J Mol Sci. 2019 Jan 9;20(2):241. doi: 10.3390/ijms20020241.
Age-related macular degeneration (AMD) is the eye disease with the highest epidemic incidence, and has great impact on the aged population. Wet-type AMD commonly has the feature of neovascularization, which destroys the normal retinal structure and visual function. So far, effective therapy options for rescuing visual function in advanced AMD patients are highly limited, especially in wet-type AMD, in which the retinal pigmented epithelium and Bruch's membrane structure (RPE-BM) are destroyed by abnormal angiogenesis. Anti-VEGF treatment is an effective remedy for the latter type of AMD; however, it is not a curative therapy. Therefore, reconstruction of the complex structure of RPE-BM and controlled release of angiogenesis inhibitors are strongly required for sustained therapy. The major purpose of this study was to develop a dual function biomimetic material, which could mimic the RPE-BM structure and ensure slow release of angiogenesis inhibitor as a novel therapeutic strategy for wet AMD. We herein utilized plasma-modified polydimethylsiloxane (PDMS) sheet to create a biomimetic scaffold mimicking subretinal BM. This dual-surface biomimetic scaffold was coated with laminin and dexamethasone-loaded liposomes. The top surface of PDMS was covalently grafted with laminin and used for cultivation of the retinal pigment epithelial cells differentiated from human induced pluripotent stem cells (hiPSC-RPE). To reach the objective of inhibiting angiogenesis required for treatment of wet AMD, the bottom surface of modified PDMS membrane was further loaded with dexamethasone-containing liposomes via biotin-streptavidin linkage. We demonstrated that hiPSC-RPE cells could proliferate, express normal RPE-specific genes and maintain their phenotype on laminin-coated PDMS membrane, including phagocytosis ability, and secretion of anti-angiogenesis factor PEDF. By using in vitro HUVEC angiogenesis assay, we showed that application of our membrane could suppress oxidative stress-induced angiogenesis, which was manifested in decreased secretion of VEGF by RPE cells and suppression of vascularization. In conclusion, we propose modified biomimetic material for dual delivery of RPE cells and liposome-enveloped dexamethasone, which can be potentially applied for AMD therapy.
年龄相关性黄斑变性（AMD）是发病率最高的眼部疾病，对老年人群影响极大。湿性 AMD 通常具有新生血管化的特征，会破坏正常的视网膜结构和视觉功能。迄今为止，挽救晚期 AMD 患者视力功能的有效治疗选择非常有限，尤其是在湿性 AMD 中，视网膜色素上皮和布鲁赫膜结构（RPE-BM）被异常血管生成破坏。抗 VEGF 治疗是治疗后者的有效方法AMD 类型; 然而，它不是一种治愈疗法。因此，对于持续性治疗，需要重建 RPE-BM 的复杂结构并控制血管生成抑制剂的释放。本研究的主要目的是开发一种具有双重功能的仿生材料，该材料可以模拟 RPE-BM 结构并确保血管生成抑制剂的缓慢释放，作为治疗湿性 AMD 的新策略。我们在此利用等离子体改性的聚二甲基硅氧烷（PDMS）片来创建模仿视网膜下 BM 的仿生支架。这种双表面仿生支架涂有层粘连蛋白和载有地塞米松的脂质体。PDMS 的顶表面通过共价键接枝层粘连蛋白，并用于培养从人诱导多能干细胞（hiPSC-RPE）分化而来的视网膜色素上皮细胞。为了达到治疗湿性 AMD 所需的抑制血管生成的目的，通过生物素-链霉亲和素连接，进一步在改性 PDMS 膜的底表面负载载有地塞米松的脂质体。我们证明 hiPSC-RPE 细胞可以在涂有层粘连蛋白的 PDMS 膜上增殖、表达正常的 RPE 特异性基因并保持其表型，包括吞噬能力和分泌抗血管生成因子 PEDF。通过体外 HUVEC 血管生成试验，我们表明我们的膜可以抑制氧化应激诱导的血管生成，这表现为 RPE 细胞分泌的 VEGF 减少和血管化受到抑制。总之，我们提出了用于双重递送 RPE 细胞和包封地塞米松的脂质体的改良仿生材料，该材料可潜在用于 AMD 治疗。
