Abstract
Abstract: :
Purpose: Keratoconus is a non-inflammatory disease characterized by progressive thinnning and scarring of the the central cornea with alterrations in the stroma. Clinical studies provide strong indication for a major part of genes in its etiology. Our purpose was to examine the genetic manifestation of 5600 human genes in the cornea of diseased corneas with special regard to the stroma and the regulation of extracellular matrix compounds, which were investigated as well by electron-scattering. Methods: RNA of stroma and epithel of 2 corneas was prepared from a patient with keratoconus and one with Phthisis bulbi. Microarrays were performed using HuGene FL 5600 Chips (Affymetrix, USA), results were analysed by Gene Chip 3.1 Analysis Suite Software. Different orientated sections of the normal and diseased corneas were analysed by transmission electron microscopy and electron diffraction using EM912 Omega (Leo, Jena, Germany). Results: In keratoconus corneas there was an upregulation of different cytokeratins, kollagen XV, metalloproteases and the inhibitor alpha-2-macroglobulin. A down-regulation of kollagen IV, keratinocyte growth factor, fibronectin, versican, cadherin, small-proline-rich protein and clathrin was found. The orthogonal arrangement of the collagen fibrills seemed to be altered in the central part of keratoconus corneas. Conclusion: Stroma of keratoconus patients is thinned and appear to have less keratocytes than normal corneas. Slightly decreased levels of superoxidedismutase indicate affection of keratocytes which are responsible for the maintenance, remodeling and balance of the extracellular matrix. Due to the reduced number of keratocytes and down-regulation of growth factors and adhesion molecules for the extracellular matrix, disorder of the stromal extracellular compounds becomes likely.
Keywords: 374 cornea: stroma and keratocytes • 417 gene/expression • 472 microscopy: electron microscopy