Purpose
To investigate the presence of inflammatory cytokines in corneal washes of patients with pterygium over time and the presence of markers of recurrence: MEFV, SCD5, and CD43 in surgically resected samples.
Methods
Eleven eyes of 11 patients (mean age: 56; 5 female and 6 male) with presence of pterygium were included in the study along with 20 controls (mean age: 50; 10 female and 10 male) with normal corneas and no history of contact lens wear. Corneal washes prior to surgical resection, at 2 weeks, 3 months and 1 year post operatively were collected using a silicone corneal bath and micropipette after application of 2 drops of normal saline. A cytometric bead array was used to determine levels of inflammatory cytokines interleukin (IL)6, IL8, and Vascular Endothelial Growth Factor (VEGF). The resected pterygium was fixed in 4% formaldehyde, and processed for immunofluorescence or immunohistochemistry using antibodies against Mediterranean fever (MEFV) and Cluster of Differentiation (CD)43, and CD31 and D2-40 respectively.
Results
Of the 11 eyes that were included in the study, none had a recurrence during the one year follow-up. Stromal and subepithelial neovascularization was regularly noted throughout the lesions (Fig. 1A). D2-40 which is a marker for epithelial-mesenchymal-transition was upregulated in the epithelium at the advancing edge with dissolution of the basement membrane (Fig. 1B). Basal epithelium of the pterygium showed MEFV bright and SCD5, CD43 dim fluorescence(Fig. 1C, 1D). Both IL-6 and VEGF were significantly elevated in patients with pterygium compared to the normal controls. We observed a peak at week 2 post operatively and return to control levels after one year (Fig. 2).
Conclusions
The significantly higher levels of IL-6 (p=0.016) and VEGF (p=0.005) in corneal washes in pre-op pterygia compared to control eyes and their return to normal levels at 1 year post-op indicate the possibility of using cytokines in corneal washes as prognostic indicators of recurrent pterygium.
Keywords: 486 cornea: tears/tear film/dry eye •
665 pterygium •
599 microscopy: light/fluorescence/immunohistochemistry