Receptor Mops Up Angiogenesis Factors to Keep Cornea Clear
VEGFR3 absorbs angiogenesis factors; might be useful for anti-angiogenic therapy
THURSDAY, July 20 (HealthDay News) -- Researchers have found that the cornea remains avascular -- a requirement for clear vision -- because the underlying epithelium acts as a sink absorbing local pro-angiogenic factors, according to a report published online July 18 in the Proceedings of the National Academy of Sciences Early Edition.
Reza Dana, M.D., M.P.H., from The Schepens Eye Research Institute and Massachusetts Eye and Ear Infirmary at Harvard Medical School in Boston, and colleagues suspected the reason the cornea remains free of blood vessels was due to the presence of vascular epithelial growth factor receptor 3, or VEGFR3, in corneal epithelium. VEGFR3 strongly binds angiogenic factors like VEGF C and D.
In their study, the investigators found that the corneal epithelium inhibits angiogenesis largely due to overexpression of VEGFR3 in this region. Without the epithelium, the cornea becomes infiltrated with blood vessels but can be inhibited by ectopic expression of a VEGFR3 chimeric protein. The authors confirmed VEGFR3's role in anti-angiogenesis by showing that ex vivo corneal cultures treated with a VEGFR3 neutralizing antibody were unable to suppress blood vessel growth and had increased corneal vascularization.
The authors believe their work not only reveals the mechanism for avascularity in the cornea, including a "check and balance" system in response to inflammation, but may also have applications outside the eye. "Nonocular applications could include induction of VEGFR3 overexpression by tumor epithelia to suppress angiogenesis, just to name a few," they write.