title: Distribution of extracellular matrix proteins in pterygia: an immunohistochemical study.
abstract: OBJECTIVE
  This study was carried out to monitor the expression of extracellular matrix proteins (ECMs) and metalloproteinases (MMPs) in pterygial tissue.
  
  
  METHODS
  Twenty primary nasal pterygia were studied by indirect routine immunohistochemistry using 13 different primary antibodies against 8 ECMs (five collagens, fibronectin, heparan sulfate, and laminin) fibroblast growth factor (bFGF), von Willebrand factor (vWF), and 3 MMPs (8, 9, and 13). Secondary antibodies were fluoresceinated. Intensity of reaction on individual sections was graded semi-quantitatively.
  
  
  RESULTS
  No expression of collagens I, II, and VII was found. Antibodies against collagen III reacted strongly positively (+++) with the entire pterygial stroma. Collagen IV expression was strongly positive in the wall of pterygial blood vessels, moderately positive (++) in the epithelial basement membrane, and only weakly positive (+) all over the stroma. Antibodies against fibronectin reacted moderately positively with stroma, blood vessel walls and epithelial basement membrane. Heparan sulfate was strongly expressed in the blood vessel walls and epithelial basement membrane. Antibodies against bFGF reacted only with pterygial epithelium. Laminin was strongly expressed in blood vessel wall, moderately (++) in the epithelial basement membrane and weakly over the entire stroma. vWF was strongly positive (+++) with pterygial blood vessel walls. Antibody reactions for MMPs differed. It was strong with pterygial epithelium (MMPs 8, 9 and 13), strong to moderate with pterygial stroma (MMPs 8 and 13 versus 9), and absent to weak with pterygial vascular walls (MMPs 8 and 13 versus 9).
  
  
  CONCLUSIONS
  This study documents the presence of several ECMs but excludes the expression of others in pterygial tissues. The results especially indicate an active involvement of MMPs 8, 9 and 13 in the pathogenesis of pterygia.
authors.affiliation: Institute for Experimental Ophthalmology, Rheinische Friedrich-Wilhelms-University Bonn, Sigmund Freud Strasse 25, 53105, Bonn, Germany.
authors.forename: Wallid
authors.initials: W
authors.lastname: Naib-Majani
authors.forename: Isam
authors.initials: I
authors.lastname: Eltohami
authors.forename: Nicolas
authors.initials: N
authors.lastname: Wernert
authors.forename: William
authors.initials: W
authors.lastname: Watts
authors.forename: Harald
authors.initials: H
authors.lastname: Tschesche
authors.forename: Uwe
authors.initials: U
authors.lastname: Pleyer
authors.forename: Winrich
authors.initials: W
authors.lastname: Breipohl
mesh_terms: D000328:Adult; D000368:Aged; D016326:Extracellular Matrix Proteins / Q000378:metabolism*; D005260:Female; D019084:Fluorescent Antibody Technique, Indirect; D006801:Humans; D008297:Male; D045726:Metalloproteases / Q000378:metabolism*; D008858:Microscopy, Phase-Contrast; D008875:Middle Aged; D011625:Pterygium / Q000378:metabolism* / Q000473:pathology
chemical_list: D016326:Extracellular Matrix Proteins; D045726:Metalloproteases