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Corina White, Ronke Olabisi; The effects of scaffold rigidity on retinal pigment epithelial cells. Invest. Ophthalmol. Vis. Sci. 2016;57(12):5323.
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© ARVO (1962-2015); The Authors (2016-present)
Although transplantation of retinal pigment epithelial(RPE) cells has shown promise for the treatment of retinal degenerative diseases, this therapeutic approach is not without challenges. Two major challenges that must be addressed are RPE cell migration and dedifferentiation and inflammatory response. In other areas of tissue engineering such as bone and neural engineering, it is well established that scaffold rigidity has significant effects on cells. The aim of this work is to understand how the rigidity of a scaffold, a relatively unexplored design aspect in retinal tissue engineering, affects RPE cells, particularly the pathways associated with the aforementioned challenges.
Scaffolds were fabricated with poly(ethylene glycol) diacrylate(PEGDA) using UV photopolymerization. The scaffolds were designed to have different elastic moduli, higher modulus correlates to higher rigidity, through the use of different molecular weight PEGDA. ARPE-19 cells were cultured on these scaffolds. Cells cultured on scaffolds and TCPS were analyzed using fluorescent microscopy, metabolic activity assay, and real time PCR.
Fluorescent images revealed that cells demonstrated qualitatively different adhesion patterns on scaffolds of varying moduli. In addition, when normalized to day 1 metabolic activity, cells on high modulus scaffolds increased metabolic activity to a significantly higher level compared to other groups on day 14 (p<0.05). The gene expression of four genes associated with inflammation and RPE dedifferentiation were analyzed. On day 7, the fold change expression of IL-6 and IL-8 were significantly different on the two scaffolds (p<0.05).
Scaffold rigidity is an important design parameter in several areas of tissue engineering but remains relatively unexplored in retinal tissue engineering. This study demonstrates that scaffold rigidity affects cell adhesion, activity, and expression. Though more exploration is needed, this begins to lay a foundation for optimizing scaffold rigidity to promote long term success of RPE scaffold implants.
This is an abstract that was submitted for the 2016 ARVO Annual Meeting, held in Seattle, Wash., May 1-5, 2016.
ARPE-19 cells cultured on TCPS (A), high (B), and low (C) modulus scaffolds stained for nuclei (blue) and dead (red) cells.
(A) Cellular metabolic activity of ARPE-19 cells on Days 7 &14 on different substrates. (B) Gene expression of cells cultured on scaffolds of varying rigidity represtented as fold change relative to TCPS. *p<0.05, Student's T, #p<0.05, ANOVA
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