Abstract
Purpose :
There is limited information on the relationship between meibum composition and disease severity of meibomian gland dysfunction (MGD). The purpose of this study was to analyze the molecular components of meibum collected from individuals with no MGD, mild-to-moderate MGD, and severe MGD.
Methods :
Adults with and without MGD were enrolled in a prospective, multicenter, exploratory clinical trial (ClinicalTrials.gov Identifier: NCT01979887). MGD disease status and severity were evaluated and defined based on maximum meibum quality scores, Schirmer test results, and Subject Ocular Symptom Questionnaire responses. Based on this, participants were grouped into non-MGD (group A), mild-to-moderate MGD (group B), and severe MGD (group C). The cholesteryl ester / wax ester molar ratio (RCE/WE) and aldehyde / wax ester molar ratio for meibum samples from the groups was measured using 1H-NMR spectroscopy by individuals masked to the group assignments.
Results :
A total of 69 meibum samples were included in the analysis, 24 each from the non-MGD and mild-to-moderate MGD groups and 21 from the severe MGD group. The average molar ratio of cholesteryl ester to wax ester was 51% lower (P = 0.038) for group B compared with group A, 52% lower (P = 0.16) for group C compared with group B, and 76% lower (P = 0.002) for group C compared with group A. The average molar ratio of aldehydes to wax ester was 277% higher (P = 0.07) for group B compared with group A, 190% higher (P = 0.003) for group C compared with group B, and 992% higher (P < 0.001) for group C compared with group A.
Conclusions :
These findings demonstrate that RCE/WE may have a direct impact on MGD pathophysiology and ocular surface lipid homeostasis, with lowest ratios apparent in the severe MGD group. To the best of our knowledge, this is the first report of higher aldehyde to wax ester molar ratios reported in the meibum secretions of individuals with severe MGD compared with mild/moderate MGD and no MGD. Aside from poor lipid quality in individuals who have MGD leading to tear film instability and evaporative tear loss, the aldehydes in the abnormal meibum secretions mix into the tears and can potentially contribute to the chronic ocular surface inflammation that has been associated with dry eye disease. The findings from this biochemical analysis of meibum can potentially help identify targets for MGD treatment.
This abstract was presented at the 2023 ARVO Annual Meeting, held in New Orleans, LA, April 23-27, 2023.