Angiogenin for the Diagnosis and Grading of Dry Eye Syndrome

Abstract

Purpose: To investigate the properties of angiogenin (ANG) as a potential tool for the diagnosis and grading ofdry eye syndrome (DES) by analyzing tear protein profiles. Methods: Tear samples were collected with capillary tubes from 52 DES patients and 29 normal individuals ascontrols. Tear protein profiles were analyzed with an immunodot blot assay as a screening test. To confirmthat the tear ANG levels were in inverse proportion to the disease severity grade, the ANG and lactoferrin (LF)tear contents of normal controls and DES patients were compared in an enzyme-linked immunosorbent assay. Results: In the immunodot blot assay, the ANG area was lower in patients with grades 3 and 4 DES than innormal controls. The areas of basic fibroblast growth factor, transforming growth factor β2, and interleukin 10were significantly greater than those of normal controls only in grade 4 DES patients, but these proteins werenot linearly correlated with dry eye severity. Upon enzyme-linked immunosorbent assay analysis, the meanconcentrations of ANG and LF decreased significantly as dry eye severity increased, except between grades1 and 2. In addition, the ratios of ANG and LF to total tear proteins were correlated significantly with DES severity. Conclusions: ANG level was significantly lower in DES patients than in normal controls, and was significantlycorrelated with the worsening severity of DES, except between grades 1 and 2, as was LF. Therefore, ANGmay be a useful measure of DES severity through proteomic analysis.