| Abstract |
Inherited retinal dystrophies and age-related macular degeneration (AMD)
are leading causes of blindness. Current treatments only slow disease
progression in a minority of patients, therefore it is important to
develop new treatments that can regenerate lost cells, restore retinal
function and halt disease progression. Retinal progenitor cells have the
potential to replace degenerating photoreceptors in retinal diseases. This
thesis explores the viability of using immortalised human foetal retinal
progenitor cells for this purpose, and aims to elucidate the trophic
factors required, in vitto, to drive these cells towards retinal cell
lineages. We also examine their potential to survive, integrate and
differentiate in the diseased and developing rat retina. Two human foetal
retinal progenitor cell lines were established by infecting retinal foetal
tissue with the temperature-sensitive tsT-SV40 antigen. The immortalised
progenitor cells were compared to primary human foetal retinal progenitor
cultures, and both were shown to express similar markers of neural
progenitor cells and early neuronal cell types. Several trophic factors
were investigated, including serum, retinoic acid and conditioned medium,
with respect to their ability to influence gene expression. Serum appeared
to induce expression of ganglion cell markers, and conditioned medium
stimulated cell proliferation. Cells were also grafted into neonatal
hooded Lister rats and RCS dystrophic rats, and neither the primary nor
the immortalised progenitor cells demonstrated integration into the retina.
In the RCS rat, cells were engulfed by host macrophage/microglia and
showed no signs of integration or expression of neuronal markers.
Immortalised cells, in vivo, stained positively for Ki67 and low levels of
nestin, but exhibited limited abitity to differentiate or integrate. These
data indicate that immortalised progenitor cells maintain many
characteristics of unimmortalised progenitor cells, and suggest that
immortalisation of retinal progenitors may have long term therapeutic
possibilities.
|
|---|
