Abstract
Purpose: :
to evaluate the protein expression of several angiogenic mediators in the conjunctival epithelium of patients with chronic ocular surface inflammatory diseases.
Methods: :
Impression cytology specimens were collected from the inferior and the superior bulbar conjunctiva of patients with chronic ocular surface inflammatory diseases, including Sjogren’s syndrome, ocular rosacea, conjunctival chalasis and ocular cicatricial pemphygoid, as well as from healthy volunteers. Cells were transferred to glass slides by repeated printing. Expression of Vascular Endothelial Growth Factor (VEGF), VEGF receptor 1 (Flt-1), VEGF receptor 2 (Flk-1) and Pigment Epithelial Derived Factor (PEDF) was evaluated by immunocytochemistry using mouse and rabbit anti-human monoclonal antibodies for these proteins. Digital image analysis using ImagePro-Plus software (Media Cybernetics, Silver Springs, MD) was performed to quantify the expression of these mediators. A mean intensity stain index (ISI) was calculated from digital images captured from sequential fields of conjunctival epithelial cells in each coverslip. The mean ISI values of the mediators from patients with ocular surface inflammatory disorders were compared to that of controls.
Results: :
The mean ISI score of VEGFR-1 (Flt-1) in the conjunctival epithelium of healthy controls was 67.9 ± 21.3 compared to 32.5±12.6 in patients with chronic inflammation (p<0.001). The mean ISI score of VEGFR-2 (Flk-1) was 57.8±27.9 in healthy individuals (p=0.05) compared to 42.2±26.7 in patients with chronic inflammation. No significant differences were evident in the expression of VEGF between patients and controls, as well as in the expression of PEDF.
Conclusions: :
The protein expression of VEGF-specific membrane receptor (VEGFR-1/Flt-1 and VEGFR-2/Flk-1) in the conjunctival epithelium is downregulated in chronic ocular surface diseases. This can be a result of chronic inflammation or of reduced innervation of the ocular surface epithelium, which are common to these diseases.
Keywords: conjunctiva • vascular endothelial growth factor • receptors