heparitin-sulfate and Keratoconus

Keratoconus has classically been defined as a noninflammatory disorder, although recent studies show elevated levels of inflammatory markers suggesting that keratoconus could be, at least in part, an inflammatory condition. Heparanase upregulation has been described in multiple inflammatory disorders. In this article, we study the differential expression of heparanase in cornea and tears from keratoconus patients and healthy controls.. A transcriptomic approach was used employing quantitative polymerase chain reaction to analyze the expression of heparanase and heparanase 2 in stromal and epithelial corneal cells. The protein expression was analyzed by immunohistochemistry in corneal sections. Enzymatic activity in tears was measured using [. Heparanase transcription was detected in stromal and epithelial cells and appeared upregulated in keratoconus. Overexpression of the enzyme was also detected by immunohistochemistry. Corneal expression of heparanase 2 was detected in some cases. Heparanase catalytic activity was found in tears and displayed a positive correlation with the degree of keratoconus.. Heparanase overexpresses in keratoconic corneas, possibly reinforcing the inflammatory condition of the pathology. The presence of heparanase activity in tears allows us to propose its use as a biomarker for the diagnosis of the disorder.

Topics: Biomarkers; Cells, Cultured; Cornea; Glucuronidase; Heparitin Sulfate; Humans; Keratoconus; Tears; Up-Regulation

Basic and acidic fibroblast growth factor (bFGF, aFGF) binding sites were determined in frozen sections of normal and keratoconus corneas. After incubation with I-125 radiolabelled growth factors, corneal binding sites were revealed by autoradiography. The growth factors were localized mainly to Descemet's membrane and to the epithelial basement membrane. FGF binding sites were generally similar in normal and keratoconus corneas. The binding specificity was demonstrated by competitive inhibition experiments with an excess of unlabelled growth factors. The binding sites were sensitive to pretreatment of the corneal sections with heparitinase. We have attributed FGF's basement membrane affinity to one of its constituents, proteoheparan sulfate. Proteoheparan sulfate, laminin, collagen type IV, and fibronectin were all revealed by immunofluorescent techniques. While keratoconus cornea stroma had less laminin but more fibronectin than normal corneas the main difference lied in type IV collagen which was overexpressed in keratoconus epithelium.

Topics: Adult; Aged; Autoradiography; Basement Membrane; Binding Sites; Chondroitin Sulfate Proteoglycans; Cornea; Descemet Membrane; Epithelium; Extracellular Matrix; Female; Fibroblast Growth Factors; Fluorescent Antibody Technique; Heparan Sulfate Proteoglycans; Heparitin Sulfate; Humans; Image Processing, Computer-Assisted; Keratoconus; Male; Middle Aged; Polysaccharide-Lyases

Topics: Animals; Autoradiography; Chondroitin Sulfates; Cornea; Culture Techniques; Dermatan Sulfate; Glucosamine; Glycosaminoglycans; Heparitin Sulfate; Keratan Sulfate; Keratitis; Keratoconus; Rabbits; Time Factors