Abstract
Purpose: :
Elevated levels of cytokine, matrix metalloproteinase (MMP) and osmolarity in the tear of dry eye patients have been reported, and these parameters are being considered as the potential biomarkers in dry eye clinical trials. The aim of this study was to examine the levels of cytokines and MMPs in human tear samples collected by Schirmer strips by Luminex technology and their correlations with subject tear osmolarity.
Methods: :
Thirty healthy volunteers were evaluated by four known methods to diagnose dry eye disease, including Schirmer’s test, tear osmolarity, ocular surface disease index (OSDI) and non-invasive tear breakup time (NITBUT). Tears were collected by Schirmer strips and proteins were recovered from the Schirmer strip in 0.5 M NaCl with 0.5% Tween 20 and analyzed for proinflammatory cytokines and MMPS by Luminex.
Results: :
All five inflammatory cytokines (IL-1α, IL-1β, IL-6, IL-8, and TNF-α) and 5 MMPs (MMP-1, MMP-2, MMP-7, MMP9, and MMP10) tested were recovered from Schirmer strips and quantified by Luminex. Calculated cytokine and MMP levels were correlated with tear osmolarity. Three cytokines (IL-1α, IL-6 and TNF-α) and 2 MMPs (MMP-9 and MMP-10) had increased concentrations that correlated with increased tear osmolarity.
Conclusions: :
Numerous cytokines and MMPs were detected in the tear samples collected using the Schirmer strip by Luminex technology. Because Schirmer’s test is routine in the assessment of dry eye, this method offers the opportunity to evaluate both the quantity and quality of the tears. A good correlation between the levels of proinflammatory cytokines and MMPs in the tear with tear osmolarity suggests that these parameters may be used as biomarkers in dry eye clinical studies.
Keywords: cytokines/chemokines • cornea: tears/tear film/dry eye