Abstract
Purpose :
Bruch’s membrane is an acellular, proteinaceous membrane that separates the retinal pigment epithelium (RPE) from the vasculature of the subretinal tissue. With age, Bruch’s membrane thickens and stiffens, which is implicated in the development of drusen in age-related macular degeneration (AMD). However, the lack of a tunable in vitro model has made it difficult to specify the impact that changes in Bruch’s membrane have on RPE health and the development of AMD. By implementing a novel, tunable model of Bruch’s membrane, the relationship between these factors can be better understood.
Methods :
In this study, a tunable model of Bruch’s membrane was created with hagfish proteins using a previously described method. Primary porcine RPE cells were cultured for up to 3 months on hagfish membranes of different thicknesses that represent varying degrees of retinal aging. During this time, monolayer integrity was monitored with trans-epithelial electrical resistance (TEER) and cell health was assessed with enzyme-linked immunosorbent assays. Cultures were also evaluated for signs of drusenoid deposits, which were then isolated and analyzed using mass spectrometry.
Results :
RPE cells cultured in this study experienced inhibited monolayer formation when grown on thickened membranes, as evidenced by decreasing TEER values over time. These cells also began to form sub-RPE deposits that contained apolipoprotein E, a common marker of drusen. Furthermore, RPE cells expressed higher levels of angiogenic factors such as TIMP-1 when cultured on thickened membranes.
Conclusions :
The results listed above combine to support a connection between the thickening of Bruch’s membrane, decreases in RPE health, and drusen development. Thickened membranes led to decreased monolayer integrity, drusen formation, and increased stress levels. These results support a connection between changes in Bruch’s membrane and RPE health in association with the development of AMD.
This abstract was presented at the 2024 ARVO Annual Meeting, held in Seattle, WA, May 5-9, 2024.