title: RPE barrier breakdown in diabetic retinopathy: seeing is believing.
abstract: Diabetic retinopathy (DR) is a major complication of diabetes and a leading cause of blindness in working-age Americans. DR is traditionally regarded as a disorder of blood-retina barriers, and the leakage of blood content is a major pathological characteristic of the disease. While the breakdown of the endothelial barrier in DR has been investigated extensively, the vascular leakage through the retinal pigment epithelium (RPE) barrier in the disease has not been widely acknowledged. As the blood content leaked through the RPE barrier causes excessive water influx to the retina, the breakdown of the RPE barrier is likely to play a causative role in the development of some forms of diabetic macular edema, a major cause of vision loss in DR. In this article, we will discuss the clinical evidences of the diabetes-induced RPE barrier breakdown, the alteration of the RPE in diabetes, the molecular and cellular mechanism of RPE barrier breakdown, and the research tools for the analysis of RPE barrier leakage. Finally, we will discuss the methodology and potential applications of our recently developed fluorescent microscopic imaging for the diabetes- or ischemia-induced RPE barrier breakdown in rodents.
authors.affiliation: Department of Medicine Endocrinology, The University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104 USA  ; Harold Hamm Diabetes Center, The University of Oklahoma Health Sciences Center, 941 S. L. Young Blvd., BSEB 302G, Oklahoma City, OK 73104 USA  ; Department of Ophthalmology, Xiangya Hospital, Central South University, Changsha, 410008 China.
authors.forename: Hui-Zhuo
authors.initials: HZ
authors.lastname: Xu
authors.forename: Zhiming
authors.initials: Z
authors.lastname: Song
authors.forename: Shuhua
authors.initials: S
authors.lastname: Fu
authors.forename: Meili
authors.initials: M
authors.lastname: Zhu
authors.forename: Yun-Zheng
authors.initials: YZ
authors.lastname: Le
keywords: Barrier; Diabetic retinopathy; Fluorescent microscopy; Leakage; Macular edema; RPE