Abstract
Purpose:
Pterygium is an overgrowth of fibrovascular tissue, often with a wing-like appearance, from the conjuctiva over the cornea. Although the pathogenesis of pterygium is not clearly understood, certain findings concerning common features in pterygium and neoplasia have been proposed, raising the possibility that a pterygium is a neoplastic-like growth disorder. There is much debate surround the pathogenesis of pterygium and a number of theories have been put forward including genetic instability, cellular proliferation, inflammatory influence, degeneration of connective tissue, angiogenesis, aberrant apoptosis or wound healing process and stem cell dysfunction. Treatment of pterygia entails its surgical excision, however in some cases they aggressively recur. The aim of this study was to analyze the cytokine tear film expression in patients with primary and recurrent pterygium.
Methods:
Tear samples from patient diagnosed with primary and recurrent pterygium, and tears from patients without pterygium diagnostics were taken as a control were analyzed. Cytokine protein arrays were performed to know relative units of 36 cytokines, with the Profiler Array Membrane (R&D Systems, Minneapolis, USA) according to the manufacturer instructions. Densitometric analysis of the dot blot was performed with Diversity and GeneTools. We considered cytokines with differential expression more or less than two times.
Results:
When we analyzed cytokine tear film expression among primary pterygium patients and controls, we found that GROa, Sicam-1, IL-8, IL-16, I-TAC, MCP-1 and MIP-1b were overexpressed; meanwhile IP-10, MIF and Serpin E1 were downregulated. Cytokine tear film expression comparison among current pterigion patients and controls showed that C5/C5a, IL-16, IL-17, IL-32a and IP-10 were overexpressed; none cytokine showed downregulation. Finally, cytokine tear film expression comparison among recurrent and primary pterygium exhibited a great overexpression of IP-10 and MIF, and MCP-1 was downregulated.
Conclusions:
Cytokine tear film expression in primary pterygium suggests an inflammatory response mediated by chemokines. In recurrent pterygium tear film, results showed an overexpression of inflammatory cytokines. Comparison among primary and recurrent pterygium exhibited a MIF and IP-10 overexpression, suggesting a chronic inflammatory process.
Keywords: 665 pterygium •
490 cytokines/chemokines •
663 proteomics