title: Alterations in the tear proteome of dry eye patients--a matter of the clinical phenotype.
abstract: OBJECTIVE
  Previous studies demonstrated alterations in the tear proteome of dry eye patients. The aim of the present study was to analyze tear protein patterns of dry eye patients considering different clinical phenotypes in order to examine their influence on tear film protein composition.
  
  
  METHODS
  We applied a surface-enhanced laser desorption/ ionization-time-of-flight (SELDI-TOF)/matrix-assisted laser desorption/ ionization-time-of-flight (MALDI-TOF)/TOF mass spectrometry (MS)-based strategy to detect/identify candidate biomarkers. Tear samples of 169 patients, enrolled in two independent studies, were analyzed. Patients were subdivided into healthy controls(CTRL: N = 39), aqueous-deficient dry eye (DRYaq: N = 40), lipid-deficient dry eye (DRYlip: N = 40), and a combination of the two (DRYaqlip: N = 40).
  
  
  RESULTS
  We uncovered six peptide/protein markers matching the stringent criteria applied for selection of reliable markers (P < 5.0E-03 in both studies). For example, proline-rich protein 4 was found to be diminished in DRYaq and DRYaqlip patients when compared to healthy subjects. Mammaglobin B and lipophilin A were found to be increased in these patients, as well as calgranulin S100A8. Remarkably, DRYlip patients revealed only slight alterations; these patients strongly deviated from the DRYaq or DRYaqlip group. With regard to classification of patients, we achieved discrimination from healthy subjects with a sensitivity and specificity ≈100% for DRYaq and DRYaqlip patients (receiver operating characteristic curve [ROC curve]: area under the curve [AUC] = 1) through use of the six-biomarker set.
  
  
  CONCLUSIONS
  This study demonstrates that different clinical phenotypes of dry eye are reflected by specific alterations of the tear film proteome. Especially a deficiency of the aqueous phase of the tear film seems to strongly influence the expression patterns of several proteins.
authors: Experimental Ophthalmology, Department of Ophthalmology, University Medical Center of the Johannes Gutenberg University, Mainz, Germany.
authors: Nils
authors: N
authors: Boehm
authors: Sebastian
authors: S
authors: Funke
authors: Michaela
authors: M
authors: Wiegand
authors: Nelli
authors: N
authors: Wehrwein
authors: Norbert
authors: N
authors: Pfeiffer
authors: Franz H
authors: FH
authors: Grus
mesh_terms: D000328:Adult; D000368:Aged; D015415:Biomarkers / Q000378:metabolism; D015352:Dry Eye Syndromes / Q000378:metabolism*; D005136:Eye Proteins / Q000378:metabolism*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010641:Phenotype; D020543:Proteome / Q000378:metabolism*; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; D013666:Tears / Q000737:chemistry*
chemical_list: D015415:Biomarkers; D005136:Eye Proteins; D020543:Proteome; C042434:tear proteins