Abstract
Purpose :
VEGF has a well-established role in neovascularization of age-related macular degeneration (AMD). However, the causes of VEGF over-expression in AMD are not clearly understood yet. This work aims to test the effect of isolation and aging of human retinal pigment epithelial (RPE) cells on VEGF expression.
Methods :
Isolation of RPE cells was achieved by containing cells on circular micro-patterns of different sizes (100, 200 and 300 μm in diameter) to replicate the atrophy of RPE cells during early to late stages of retinal degeneration in AMD. Micro-patterned substrates were made by using polydimethylsiloxane (PDMS) membranes with holes of desired sizes, manufactured in-house. The effect of aging was tested by growing micro-patterned and unpatterned RPE cultures over 1-day, 6-day and 21-day time periods. The amount of VEGF secreted to the media was measured 24 hours after patterning and/or after the end of each time period.
Results :
Higher levels of VEGF expression per cell (specific VEGF expression) were observed for cells grown on smaller pattern sizes for all time periods. In addition, aging of RPE cells grown on smaller pattern sizes significantly elevated the levels of specific VEGF expression. Particularly, the specific VEGF expression for cells grown on 100 μm circles for 21 days was over 3-fold higher than that for cells grown on the same pattern size for 24 hours.
Conclusions :
Our results indicate that increased isolation of RPE cells increases VEGF expression. Moreover, we showed that in vitro aging of RPE cells amplifies the effect of isolation. These results can help to better understand the mechanisms contributing to VEGF overexpression at different stages of AMD.
This is an abstract that was submitted for the 2016 ARVO Annual Meeting, held in Seattle, Wash., May 1-5, 2016.