Corneal neovascularization during experimental fungal keratitis.
OBJECTIVE
To investigate the development of corneal neovascularization, the corneal expression of vascular endothelial growth factor (VEGF), and the antiangiogenic effects of a VEGF-inhibitory antibody during experimental keratomycosis.


METHODS
Scarified corneas of BALB/c mice were topically inoculated with Candidaalbicans and monitored daily for corneal neovascularization. A murine gene microarray compared infected corneas to controls 1 day after inoculation. Real-time reverse transcriptase polymerase chain reaction (RT-PCR) determined levels of genes encoding VEGF-A, VEGF-B, VEGF-C, and VEGF-D and placental growth factor in infected, mock-inoculated, and normal corneas. Immunostaining localized VEGF-A in corneal sections. An anti-VEGF-A antibody that binds to murine VEGF was evaluated for effects on corneal neovascularization and fungal recovery.


RESULTS
Eyes with C. albicans keratitis manifested limbal capillary budding on the second postinoculation day, and intrastromal neovascular tufts subsequently grew at a mean rate of 250+/-80 microm/day. One day after the onset of C. albicans keratitis, VEGF-A was upregulated 12.5 fold (p=0.01) by microarray and 8.8 fold (p=0.004) by real-time RT-PCR, followed by a measured decline toward baseline over one week. VEGF-A was present in the epithelium and stroma of infected corneas. Scarification alone did not alter VEGF expression compared to the normal cornea. Anti-VEGF-A antibody significantly (p<0.01) decreased the formation of new corneal blood vessels during experimental keratomycosis without adversely affecting the fungal load of C. albicans keratitis.


CONCLUSIONS
Untreated C. albicans keratitis induces VEGF-A and leads to progressive corneal neovascularization that is preventable by a VEGF-blocking antibody.
Yuan
Xiaoyong
X
Sid W. Richardson Ocular Microbiology Laboratory, Cullen Eye Institute, Department of Ophthalmology, Baylor College of Medicine, Houston, TX 77030, USA.
Wilhelmus
Kirk R
KR
D000818:Animals; D000906:Antibodies / Q000494:pharmacology; D002176:Candida albicans / Q000187:drug effects; D002177:Candidiasis / Q000139:chemically induced / Q000150:complications / Q000382:microbiology; D003315:Cornea / Q000098:blood supply / Q000382:microbiology / Q000473:pathology; D016510:Corneal Neovascularization / Q000150:complications* / Q000382:microbiology*; D015821:Eye Infections, Fungal / Q000150:complications* / Q000382:microbiology*; D020869:Gene Expression Profiling; D005786:Gene Expression Regulation / Q000187:drug effects; D007634:Keratitis / Q000139:chemically induced / Q000150:complications* / Q000382:microbiology*; D007700:Kinetics; D051379:Mice; D008810:Mice, Inbred C57BL; D020411:Oligonucleotide Array Sequence Analysis; D020133:Reverse Transcriptase Polymerase Chain Reaction; D042461:Vascular Endothelial Growth Factor A / Q000235:genetics / Q000378:metabolism
D000906:Antibodies; D042461:Vascular Endothelial Growth Factor A