Increased Expressions of ICAM-2 and ICAM-3 in Pterygium

Purpose: Pterygium, one of the most common ocular surface diseases, is characterized by inflammatory infiltrates, proliferation, angiogenesis, fibrosis, and extracellular matrix breakdown. The objective of this study was to elucidate the levels of the intercellular adhesion molecule (ICAM)-2, and ICAM-3 gene and protein expressions in pterygium. Methods: A total of 59 patients with pterygium were included in this study. mRNA from pterygial and conjunctival autograft tissues were extracted, and real-time polymerase chain reaction on the BioMark HD dynamic array system was performed for the ICAM-2 and ICAM-3 gene expressions. ICAM-2 and ICAM-3 protein expressions using western blot and immunohistochemistry methods were also investigated in pterygial and conjunctival autograft tissues. Results: ICAM-2 and ICAM-3 gene expressions were markedly augmented in pterygial tissues (P = 0.0018 and P = 0.0023, respectively). Significant increases in protein expressions in pterygial tissues were also detected for ICAM-2 and ICAM-3 (P = 0.0116 and P = 0.0252, respectively). In the immunohistochemical studies, there was a marked increase in ICAM-3 (P = 0.0152), but not in ICAM-2 (P = 0.1041), protein expressions in pterygial tissues. Significant positive correlations between pterygia grading with ICAM-2 protein expression (P = 0.0398) and ICAM-3 immunohistochemical scores (P = 0.0138) were observed. Conclusion: These results demonstrate, for the first time, the expressions of ICAM-2 and ICAM-3 in the pterygium. These findings may help to understand the signal transduction mechanisms in the pterygium formation and provide a new therapy strategy for pterygium treatment.