elastin and Pterygium

The aim of this study was to determine prolidase activity in conjunctival tissue and its relationship with pterygium.. Prolidase activity was measured in 23 pterygium and 25 healthy conjunctival tissues and the 2 groups were compared.. Prolidase enzyme activity could not be measured in either the healthy conjunctival or in pterygium tissues. The mean serum prolidase levels of the control and pterygium groups were 967.46±353.64 and 858.29±301.83, respectively. Statistically, there was no significant difference between the groups with regard to serum prolidase levels (p>0.05).. In conclusion, absence of prolidase activity in pterygium tissue indicates that there is no collagen turnover in this tissue. We may explain this finding with the elastin-rich structure of the conjunctiva.

Topics: Adult; Aged; Case-Control Studies; Collagen; Conjunctiva; Dipeptidases; Elastin; Female; Gene Expression Regulation, Enzymologic; Humans; Male; Middle Aged; Pterygium

We evaluated the expression of several extracellular matrix constituents implicated in the synthesis and reticulation of elastin in human pterygium, according to age and sex of the patients.. Pterygia and normal conjunctiva samples were divided into groups according to age (<50/≥50 years) and sex. Tissue was subjected to immunohistochemical staining with anti-lysyl oxidase (LOX), lyxyl oxidase-like 1 (LOXL-1), fibulin (FBLN)-5 and FBLN4, and fibrillin-1 (FBN1) antibodies. Specific primers for the same constituents were used in a quantitative real-time PCR (qRT-PCR) analysis to determine gene expression.. The LOXL-1 (P = 0.0002), FBLN5 (P = 0.0035), and FBN1 (P < 0.0001) mRNAs were significantly higher in pterygium than conjunctiva. No differences were found for LOX and FBLN4 mRNA. The expression of LOXL-1 was not affected by age or sex; however, pterygium from men and patients over 50 years old exhibited significantly higher FBLN5/FBN1 expression than did controls. The LOX gene expression was higher in the pathologic samples from the over 50-year-olds compared to the conjunctiva (P = 0.0396) and in men's versus women's pterygium (P = 0.0173). In general, the levels of LOX, LOXL-1, and FBLN5 decreased with age in healthy samples, while the pathology seemed to have increased expression of the three proteins, and even more so in older patients. The FBLN4 and FBN1 immunostaining was slight in all samples, displaying no differences between groups.. Several extracellular matrix constituents, LOXs, FBN1, and FBLN5, implicated in the development of elastin, are overexpressed in the subepithelial connective tissue extracellular matrix of human pterygium, supporting our hypothesis that elastic synthesis and reticulation is dysregulated in this type of pathology.

Topics: Amino Acid Oxidoreductases; Conjunctiva; Connective Tissue; Elastin; Extracellular Matrix; Extracellular Matrix Proteins; Female; Gene Expression Regulation; Humans; Immunohistochemistry; Male; Middle Aged; Pterygium; Real-Time Polymerase Chain Reaction; RNA, Messenger

Elastodysplasia and elastodystrophy are two known manifestations in the conjunctival, ie, pinguecular, part of pterygia. But the mechanisms are still not understood. The purpose of this study is to investigate the mechanism of enhanced elastin gene expression in fibroblasts from the pinguecular part of pterygia, which is related to abnormal elastic fiber expression in the pinguecular part of pterygia. Elastin in surgical specimens of normal conjunctiva and the pinguecular part of pterygia from age-matched patients was detected by immunohistochemical staining. Northern hybridization and quantification of radiolabeled tropoelastin were performed in conjunctival fibroblasts cultured under different doses of ultraviolet (UV) B irradiation, and in cultured pinguecular fibroblasts from pterygia. In vitro translation was also performed to analyze the tropoelastin production in rabbit reticulocyte lysate. The level of tropoelastin in reticulolysates from UV-treated conjunctival and pinguecular fibroblasts of pterygia was higher than in normal conjunctival fibroblasts. The coding sequence and 3'- untranslated region of tropoelastin mRNAs were amplified by reverse transcription-polymerase chain reaction, and mutations were checked by DNA sequencing. Immunohistochemical staining revealed elastin in pinguecular subepithelial connective tissues of pterygia, but not in normal conjunctiva. Tropoelastin mRNA levels were not elevated in cultured pinguecular or conjunctival fibroblasts with or without ultraviolet B irradiation. However, tropoelastin synthesis was enhanced in culture medium of pinguecular and UV-irradiated conjunctival fibroblasts, but not in normal conjunctival fibroblasts. Direct DNA sequencing revealed mutations in the 3'-untranslated region but not in the coding sequence of tropoelastin mRNA, in both pinguecular and UV-irradiated conjunctival fibroblasts. The increased expression of tropoelastin in pinguecular and UV-irradiated fibroblasts is not a result of increased levels of steady-state mRNA, but is a result of posttranscriptional modification of tropoelastin.

Topics: 3' Untranslated Regions; Animals; Cells, Cultured; Conjunctiva; Culture Media; Elastin; Fibroblasts; Gene Expression; Humans; Immunohistochemistry; Mutation; Nucleic Acid Hybridization; Pterygium; Rabbits; Reticulocytes; RNA, Messenger; Tropoelastin; Ultraviolet Rays