Tear proteomics in evaporative dry eye disease.

Area of Science:

• Ophthalmology
• Proteomics
• Biochemistry

Background:

• Dry eye disease (DED) is a prevalent condition characterized by tear film instability.
• Evaporative dry eye (EDE) is a subtype of DED where tear evaporation is excessive.
• Early detection of DED is crucial for effective management and prevention of further ocular surface damage.

Purpose of the Study:

• To investigate tear protein profile alterations in patients with early-stage evaporative dry eye (EDE) exhibiting tear film instability but no epithelial defects.
• To identify specific protein biomarkers indicative of EDE before the manifestation of overt clinical signs.

Main Methods:

• Tears were collected from 60 EDE patients (break-up time [BUT] <10 s) and 30 healthy controls (BUT >10 s).
• Tear proteins were analyzed using SDS-PAGE, immunoblotting, enzymatic digestion, and liquid chromatography-mass spectrometry (LC-ESI-QTOF-MS).
• Comparative proteomic analysis was performed against the Swiss-Prot human protein database using Mascot, with statistical analysis by t-test and Mann-Whitney test.

Main Results:

• EDE patients showed significantly lower levels of lactoferrin (20.15% vs 24.56%), lipocalin-1 (14.98% vs 17.73%), and lipophilin A-C (2.89% vs 3.63%) compared to controls.
• Serum albumin levels were significantly elevated in EDE patients (9.45% vs 3.46%).
• Proteomic analysis confirmed downregulation of lipophilin A, C, and lipocalin-1, potentially linked to post-translational modifications.

Conclusions:

• Tear protein composition changes, specifically decreased lactoferrin, lipocalin-1, and lipophilin, are evident in early-stage evaporative dry eye.
• These proteomic alterations may serve as early indicators of dry eye disease, preceding the development of more pronounced clinical signs.
• The findings highlight the potential of tear protein analysis for non-invasive early diagnosis and monitoring of dry eye disease.