Abstract
Purpose: :
The purpose of this study is to culture and establish viable autologous monolayer sheets of sheep IPE cells and RPE cells in vitro. Second, we will compare the morphology and functional aspects of the IPE and RPE cells on the monolayer sheets to ascertain the preservation of their functions.
Methods: :
Posterior IPE and RPE cells were gently scraped out of freshly enucleated sheep eyes following established protocols. Equal number of cells were seeded on pretreated human amniotic membrane and incubated for 10 days in DMEM medium supplemented with 10% FBS and Pen/Strep. Histological and immunological studies were performed on paraffin embedded sections to study the different morphological features of the cells. Phagocytosis was assayed by fluorescent microscopy after daily feeding the cells with FITC-conjugated oxidized bovine rod outer segments (1x106/ml) for 10 hours and then for 24, 48 and 72 hours.
Results: :
Amniotic membrane acts as a robust matrix for monolayer cell cultivation with cells retaining native characteristics. Both IPE and RPE cells stained positive with cytokeratin confirming their epithelial origin. IPE cells propagated similarly like RPE cells on the amniotic membrane forming monolayer sheets and in fact maintained cell to cell junctions. In addition, on the amniotic membrane, IPE cells depicted melanin granules and structural similarity to the isolated RPE cells and as seen on hematoxylin-eosin sections. Functionally, IPE cells were able to phagocyte FITC labeled rod outer segments with 20% lower efficiency in comparison to RPE cells at 10 and 24 hour incubation period. However, at 48 and 72 hour time points IPE cells showed higher accumulates of ROS than RPE cells.
Conclusions: :
TIPE cells can be grown as monolayer sheets on amniotic membrane and they resemble not only structural characteristics but also physiological properties with RPE cells in vitro. Therefore, IPE cells are ideal cells for RPE cell replacement especially when grown as monolayer sheets on amniotic membrane. This holds strong clinical significance with respect to therapeutic approaches in treatment of severe dry and exudative macular degeneration.
Keywords: age-related macular degeneration • retinal pigment epithelium • regeneration