Changes in Meibum Lipid Composition With Ocular Demodex Infestation.

PURPOSE

The purpose of this study was to understand the impact of Demodex infection in the lipid component of meibum in patients.

METHODS

The meibum samples were collected from four groups of subjects: (1) Demodex-negative with non-MGD (D-M-; n = 10); (2) Demodex-positive with non-MGD (D+M-; n = 10); (3) Demodex-negative with MGD (D-M+; n = 10); and (4) Demodex-positive with MGD (D+M+; n = 10). A liquid chromatography-mass spectrometry (LC-MS) system consisting of ultra-performance liquid chromatography and a Q Exactive high-resolution mass spectrometer was used for lipids separation and detection.

RESULTS

Compared with the D-M- group, the D+M- group had lower levels of phosphatidylcholines (PCs) and lysophosphatidylcholines (LPCs) and higher levels of phosphatidylethanolamines (PEs). Compared with the D-M+ group, the levels of sphingomyelins (SMs) and PCs in the D+M+ group were decreased, whereas the levels of (O-acyl)-ω-hydroxy fatty acids (OAHFAs), ceramides (CERs), LPCs, and diacylglycerols (DGs) were significantly increased. Triacylglycerols (TGs), DGs, CERs, and OAHFAs were decreased in D-M+ group, whereas levels of PEs, phosphatidylinositols, and phosphatidylglycerols were increased in meibum obtained from the D-M+ group compared with those in the D-M- group. TGs, SMs, CERs, and PEs were decreased in the D+M+ group, whereas levels of LPCs, LPEs, PCs, and PEs were increased in meibum from the D-M+ group compared with those in the D+M- group.

CONCLUSIONS

To the best of our knowledge, this is the first study to assess the changes in meibum from patients with ocular Demodex infestation. The significant increase of OAHFAs in the Demodex-positive group suggest that OAHFAs may be associated with the progress of ocular Demodex infections.

TRANSLATIONAL RELEVANCE

OAHFAs could be a potential new therapeutic target for ocular Demodex infestation.