Abstract
Purpose: :
Dry eye in postmenopausal women is thought to be associated with tear film instability and increased tear osmolality, coupled with changes in hormonal regulation of the meibomian glands and changes to the inflammatory environment of the ocular surface. The purpose of this work is to compare the presence of inflammatory proteins in the tear film of postmenopausal women, with and without dry eye.
Methods: :
Postmenopausal women were examined and categorized according to dry eye status using a modified Delphi/DEWS 4-stage algorithm. Representative tear samples (4 from each group) were selected for cytokine array analysis in 4 categories: normal (non-dry eye), stage 2 dry eye, stage 3 dry eye with central corneal staining, stage 3 dry eye with significant overall corneal staining and no central staining, and stage 2/3 with high tear osmolarity. Individual tear samples were applied to custom-40 RayBio Human Cytokine Antibody Microarray G Series slides, which were imaged using a Typhoon 9410 laser imager and ImageQuant Image Analysis Software.
Results: :
Of the 40 inflammatory mediators assessed, 16 were present across tear samples and 3 were found in all samples: epidermal growth factor (EGF), growth related oncogene (GRO), tissue inhibitor metalloproteinase-2 (TIMP-2). TIMP-1 and matrix metalloproteinase-9 (MMP-9), were not shown in normals, and were greatest in level-3 dry eye with central corneal staining. Tumor necrosis factor-alpha (TNF-) was only seen in subjects with high osmolarity.
Conclusions: :
Increased MMP-9 and TIMP-1 were shown with increasing dry eye severity, consistent with the hypothesis of up regulation of inflammatory processes in corneas with cellular damage present in central corneal staining. The custom microarray technique is promising for the detection of inflammatory mediators in individual small volume (as low as 0.75µL) tear samples from postmenopausal women.
Keywords: cornea: tears/tear film/dry eye • cytokines/chemokines