PURPOSE. To study the in vitro angiogenic activity of human conjunctival an
d limbal epithelial cells and conjunctival, limbal, and corneal fibroblasts
in a three-cell-type coculture model.
METHODS. Human umbilical vein endothelial cells (EC) were cocultured with e
pithelial cells, fibroblasts, or epithelial cells and fibroblasts to test t
heir effect on EC morphogenesis. Neutralizing antibodies to some known angi
ogenic factors were added to the culture to see whether the EC morphogenesi
s may be blocked by a particular antibody.
RESULTS. Conjunctival and limbal epithelial cells exhibited very little or
no stimulatory effect on EC tube formation when examined in an EC-epithelia
l cell coculture system. In contrast, conjunctival, limbal, and corneal fib
roblasts all promoted EC morphogenesis when examined under the same culture
conditions. Fibroblast-induced EC morphogenesis was inhibited by addition
of anti-vascular endothelial growth factor (VEGF) and/or anti-basic fibrobl
ast growth factor (bFGF) antibodies to the culture medium. In the three-cel
l-type coculture system consisting of ECs, fibroblasts, and epithelial cell
s, limbal epithelial cells (but not conjunctival epithelial cells) exhibite
d a strong inhibitory effect on fibroblast-induced EC tube formation.
CONCLUSIONS. The proangiogenic activity of ocular surface fibroblasts is pr
obably mediated through a paracrine mechanism by VEGF and bFGF. Limbal epit
helial cells, but not conjunctival epithelial cells, inhibit fibroblast-sti
mulated angiogenesis.