title: Tropoelastin and fibulin overexpression in the subepithelial connective tissue of human pterygium.
abstract: OBJECTIVE
  To evaluate possible changes in the collagen and elastic components of the subepithelial connective tissue of human pterygium.
  
  
  METHODS
  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.
authors.affiliation: Department of Ophthalmology, University Hospital Principe de Asturias, University of Alcalá, Alcalá de Henares, Madrid, Spain. cinta.perezrico@gmail.com
authors.forename: Consuelo
authors.initials: C
authors.lastname: Pérez-Rico
authors.forename: Gemma
authors.initials: G
authors.lastname: Pascual
authors.forename: Sandra
authors.initials: S
authors.lastname: Sotomayor
authors.forename: María Ángeles
authors.initials: MÁ
authors.lastname: Montes-Mollón
authors.forename: Cynthia
authors.initials: C
authors.lastname: Trejo
authors.forename: Takako
authors.initials: T
authors.lastname: Sasaki
authors.forename: Robert
authors.initials: R
authors.lastname: Mecham
authors.forename: Juan Manuel
authors.initials: JM
authors.lastname: Bellón
authors.forename: Julia
authors.initials: J
authors.lastname: Buján
mesh_terms: D002135:Calcium-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D024042:Collagen Type I / Q000378:metabolism; D024061:Collagen Type III / Q000378:metabolism; D003228:Conjunctiva / Q000378:metabolism; D003238:Connective Tissue / Q000378:metabolism*; D016326:Extracellular Matrix Proteins / Q000235:genetics / Q000378:metabolism*; D006801:Humans; D007124:Immunoenzyme Techniques; D008875:Middle Aged; D011625:Pterygium / Q000378:metabolism*; D012333:RNA, Messenger / Q000235:genetics; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014333:Tropoelastin / Q000235:genetics / Q000378:metabolism*
chemical_list: D002135:Calcium-Binding Proteins; D024042:Collagen Type I; D024061:Collagen Type III; C119630:EFEMP1 protein, human; D016326:Extracellular Matrix Proteins; D012333:RNA, Messenger; D014333:Tropoelastin; C084612:fibulin 2