Tropoelastin and Fibulin Overexpression in the Subepithelial Connective Tissue of Human Pterygium

• Published in: American journal of ophthalmology 2011, Vol.151 (1), p.44-52
• Main Authors: Pérez-Rico, Consuelo, Pascual, Gemma, Sotomayor, Sandra, Montes-Mollón, María Ángeles, Trejo, Cynthia, Sasaki, Takako, Mecham, Robert, Bellón, Juan Manuel, Buján, Julia
• Format: Article
• Language: English
• Subjects: Biological and medical sciences; Calcium-Binding Proteins - genetics; Calcium-Binding Proteins - metabolism; Collagen; Collagen Type I - metabolism; Collagen Type III - metabolism; Conjunctiva - metabolism; Connective Tissue - metabolism; Diseases of eyelid, conjunctiva and lacrimal tracts; Extracellular Matrix Proteins - genetics; Extracellular Matrix Proteins - metabolism; Humans; Immunoenzyme Techniques; Light; Medical sciences; Microscopy; Middle Aged; Miscellaneous; Ophthalmology; Pathogenesis; Proteins; Pterygium - metabolism; Reverse Transcriptase Polymerase Chain Reaction; RNA, Messenger - genetics; Rodents; Standard deviation; Tropoelastin - genetics; Tropoelastin - metabolism; Wound healing
• ISSN: 0002-9394; 1879-1891
• DOI: 10.1016/j.ajo.2010.07.012

Purpose To evaluate possible changes in the collagen and elastic components of the subepithelial connective tissue of human pterygium. Design Immunohistochemical study. Methods Immunohistochemical staining using antitropoelastin, anti-fibulin-2, and anti-fibulin-3 antibodies was performed in 10 normal conjunctival and 20 pterygium specimens. Masson trichome staining also was performed to study subepithelial connective tissue. Sirius red staining was used to identify collagen type I and III components. Tropoelastin, fibulin-2, and fibulin-3 messenger ribonucleic acid (mRNA) expressions were analyzed in 9 conjunctival and 12 pterygium specimens by quantitative real-time polymerase chain reaction assay. Results The subepithelial connective tissue and vessels were more predominant in pterygium compared with the normal conjunctival tissue. Amorphous subepithelial zones were observed in the areas of the pterygium tissue, but not in normal conjunctiva. Increased tropoelastin staining was seen in the pterygium tissue with areas of degenerative changes or immature formation of elastic fibers, as well an increase in tropoelastin mRNA, in contrast with fibulin-2 and fibulin-3 messenger levels. Fibulin-2 and fibulin-3 expression was colocalized in the subepithelial connective tissue and was distributed along blood and lymphatic vessels. Collagen type III, an immature form of collagen, was increased in the pathologic samples in association with a tissue remodeling process. Conclusions Elastin metabolism is dysregulated in the pathogenesis of human pterygium with tropoelastin, fibulin-2, and fibulin-3 overexpression in the subepithelial connective tissue.