title: Tear Mediators in Corneal Ectatic Disorders.
abstract: OBJECTIVE
  To compare the concentrations of 11 tear mediators in order to reveal the biochemical difference between pellucid marginal degeneration (PMD) and keratoconus (KC).
  
  
  METHODS
  We have designed a cross-sectional study in which patients with corneal ectasia based on slit-lamp biomicroscopy and Pentacam HR (keratometry values (K1, K2, Kmax), astigmatism, minimal radius of curvature (Rmin), corneal thickness (Apex and Min), indices (surface variation, vertical asymmetry, keratoconus, central keratoconus, height asymmetry and decentration)) were enrolled. Eyes of keratoconic patients were similar to the PMD patients in age and severity (K2, Kmax and Rmin). Non-stimulated tear samples were collected from nine eyes of seven PMD patients, 55 eyes of 55 KC patients and 24 eyes of 24 healthy controls. The mediators' (interleukin -6, -10, chemokine ligand 5, -8, -10, matrix metalloproteinase (MMP) -9, -13, tissue inhibitor of metalloproteinases (TIMP)-1, tissue plasminogen activator, plasminogen activator inhibitor, nerve growth factor) concentrations were measured using Cytometric Bead Array.
  
  
  RESULTS
  MMP-9 was the only mediator which presented relevant variances between the two patient groups (p = 0.005). The ratios of MMP-9 and TIMP-1 were 2.45, 0.40 and 0.23 in PMD, KC and the controls, respectively.
  
  
  CONCLUSIONS
  As far as we are aware, this is the first study that aims to reveal the biochemical differences between PMD and KC. Further studies of biomarkers to investigate the precise role of these mediators need to be defined, and it is important to confirm the observed changes in a larger study to gain further insights into the molecular alterations in PMD.
authors.affiliation: Department of Ophthalmology, Faculty of Medicine, University of Debrecen, Debrecen, Hungary.
authors.forename: Dorottya
authors.initials: D
authors.lastname: Pásztor
authors.affiliation: Department of Ophthalmology, Faculty of Medicine, University of Debrecen, Debrecen, Hungary.
authors.forename: Bence Lajos
authors.initials: BL
authors.lastname: Kolozsvári
authors.affiliation: Department of Ophthalmology, Faculty of Medicine, University of Debrecen, Debrecen, Hungary.
authors.forename: Adrienne
authors.initials: A
authors.lastname: Csutak
authors.affiliation: Department of Ophthalmology, Faculty of Medicine, University of Debrecen, Debrecen, Hungary.
authors.forename: András
authors.initials: A
authors.lastname: Berta
authors.affiliation: Orbident Refractive Surgery and Medical Center, Debrecen, Hungary.
authors.forename: Ziad
authors.initials: Z
authors.lastname: Hassan
authors.affiliation: Department of Ophthalmology, Faculty of Medicine, University of Debrecen, Debrecen, Hungary.
authors.forename: Bernadett
authors.initials: B
authors.lastname: Ujhelyi
authors.affiliation: Department of Immunology, Faculty of Medicine, University of Debrecen, Debrecen, Hungary.
authors.forename: Péter
authors.initials: P
authors.lastname: Gogolák
authors.affiliation: Department of Ophthalmology, Faculty of Medicine, University of Debrecen, Debrecen, Hungary.
authors.forename: Mariann
authors.initials: M
authors.lastname: Fodor
mesh_terms: D000328:Adult; D000368:Aged; D003315:Cornea / Q000378:metabolism*; D003316:Corneal Diseases / Q000175:diagnosis* / Q000378:metabolism; D019781:Corneal Topography; D003430:Cross-Sectional Studies; D003937:Diagnosis, Differential; D005260:Female; D006801:Humans; D007640:Keratoconus / Q000175:diagnosis* / Q000378:metabolism; D008297:Male; D020780:Matrix Metalloproteinase 9 / Q000378:metabolism; D008875:Middle Aged; D013666:Tears / Q000378:metabolism*; D019715:Tissue Inhibitor of Metalloproteinase-1 / Q000378:metabolism
chemical_list: D019715:Tissue Inhibitor of Metalloproteinase-1; D020780:Matrix Metalloproteinase 9