Patients with meibomian gland dysfunction (MGD) have significantly higher triglyceride, researchers found in a Japanese study published in The Ocular Surface.
The investigators analyzed individual lipid groups of meibum to discover symptoms that aging and MGD present, the relationship individual lipid groups have with meibum lipid composition, and objective clinical findings of lid margin and ocular surface.
Ten patients (4 male, mean age 65.6±7.9 years) with MGD were compared with 12 young healthy control individuals (6 male, mean age 25.7±3.8 years) and 12 older healthy control individuals (6 male, mean age 58.4±7.5 years).
The individuals completed a modified dry eye related Quality of Life Score questionnaire in which they reported presence of 15 subjective symptoms on a scale of 0 to 4. Researchers collected and analyzed meibum samples from each participant.
MGD obstruction grade, meibum score, and TFLL interference pattern were higher in patients with MGD compared with control individuals. The patients with MGD had higher scores for heavy sensation, blurred vision, decrease of VA and trouble focusing (P <.05). Older control individuals had more trouble focusing compared with younger control individuals (P =.0027).
Through lipid analysis, the researchers found that human meibum primarily included polar lipids, such as OAHFA and free FAs, and the nonpolar lipids of wax esters, cholesterol esters, triglycerides, and cholesterol.
Patients with MGD and older control individuals had higher polar lipids, such as cholesterol (Ch), (O-acyl)-ω-hydroxy fatty acid (OAHFA), and free fatty acid (FA). They had lower non-polar lipids, including cholesterol esters (ChEs). Vision quality and ocular fatigue were linked with presence of increased polar lipids and decreased non-polar lipids.
Male patients with MGD had significantly less nonpolar lipids, such as ChEs, compared with females.
The researchers said this may explain why men are at higher risk of developing MGD compared with women.
Triglycerides were the sole lipid that was higher in the patients with MGD compared with both older (P =.0044) and younger (P =.0001) control individuals.
“Analysis of the TG composition ratio in the meibum of MGD patients revealed that there was a significant difference in TGs between those patients and healthy subjects, both elderly and young,” the research explains. “Since we did not see any major significant differences in other lipids between the MGD patients and the age-matched elderly healthy subjects, TGs seemed to be the only lipids showing the quantitative alteration related to MGD.”
Limitations of the study included the possible contamination of meibum samples with sebum and a small sample size.
Disclosure: This research was supported by Lion Corporation. Some study authors declared affiliations with biotech, pharmaceutical, and/or device companies. Please refer to the original article for a full list of disclosures.
Suzuki T, Kitazawa K, Cho Y, et al. Alteration in meibum lipid composition and subjective symptoms due to aging and meibomian gland dysfunction. The Ocular Surface. Published online October 16, 2021. doi:10.1016/j.jtos.2021.10.003