Purpose During RPC expansion, an interesting phenomenon
occurs in which some cells grow as floating spheres and others adopt adherent
growth; we describe these two types of cells as suspension cells and adherent
cells, respectively. These two types of cells display different morphologies. In
this study, we characterized the proliferative capacity and differentiation
potential between suspension and adherent RPCs in vitro, which may be useful for the treatment of retinal
diseases.
Method 1 In this study, cultured RPCs were
sorted into suspension and adherent cells. The RPC
proliferative capacity was examined using growth curves.

2 To identify multipotent capacity of the cells under differentiation conditions, Analyses
of gene and protein expression of retinal progenitor-related markers were
performed using quantitative
polymerase chain reaction (qPCR) and immunocytochemistry.
Results: 1 The experiment
results showed that the majority of the suspension cells and adherent cells remain
express the
marker of Nestin, vimentin and Ki-67 after constantly passaged. The
expression of Nestin
and Ki-67 inthe suspension cells was
more than that of in the adherent cells.

2 The adherent cells were more likely to differentiate toward the β3-tubulin-, AP2a- and Map2-positive neuronal lineage, while the
suspension cells were more effective at differentiating into rod photoreceptors.

Conclusion:1 The suspension and adherent cells were maintained
in an undifferentiated state, although the former exhibited a greater proliferative
potential than the latter.
2 Retinal progenitor cells have tremendous potential
for the treatment of retinal degenerative diseases. Adherent RPCs may be a
potential candidate for retinal interneuron or ganglion cell substitution
therapies, whereas suspension RPCs may be preferred for photoreceptor cell
replacement.