No treatments exist to effectively treat many retinal diseases. Retinal pigmented
epithelium (RPE) and neural retina can be generated from human embryonic stem cells/induced
pluripotent stem cells (hESCs/hiPSCs). The efficacy of current protocols is, however,
limited. It was hypothesised that generation of laminated neural retina and/or RPE
from hiPSCs/hESCs could be enhanced by three dimensional (3D) culture in hydrogels.
hiPSC- and hESC-derived embryoid bodies (EBs) were encapsulated in 0.5% RGD-alginate;
1% RGD-alginate; hyaluronic acid (HA) or HA/gelatin hydrogels and maintained until
day 45. Compared with controls (no gel), 0.5% RGD-alginate increased: the percentage
of EBs with pigmented RPE foci; the percentage EBs with optic vesicles (OVs) and pigmented
RPE simultaneously; the area covered by RPE; frequency of RPE cells (CRALBP+); expression
of RPE markers (TYR and RPE65) and the retinal ganglion cell marker, MATH5. Furthermore,
0.5% RGD-alginate hydrogel encapsulation did not adversely affect the expression of
other neural retina markers (PROX1, CRX, RCVRN, AP2α or VSX2) as determined by qRT-PCR,
or the percentage of VSX2 positive cells as determined by flow cytometry. 1% RGD-alginate
increased the percentage of EBs with OVs and/or RPE, but did not significantly influence
any other measures of retinal differentiation. HA-based hydrogels had no significant
effect on retinal tissue development. The results indicated that derivation of retinal
tissue from hESCs/hiPSCs can be enhanced by culture in 0.5% RGD-alginate hydrogel.
This RGD-alginate scaffold may be useful for derivation, transport and transplantation
of neural retina and RPE, and may also enhance formation of other pigmented, neural
or epithelial tissue.