Abstract
Purpose :
We previously reported the causative bacteria of meibomian gland (MG) inflammation (meibomitis) by using a bacterial culture of meibum. In this study, comprehensive analysis of the human microbiome of the eyelid skin, conjunctival sac, and MG meibum was performed via DNA sequencing.
Methods :
This study involved 24 healthy subjects (6 males and 6 females, age range: 20-35 years; 6 males and 6 females, age range: 60-70 years) without any eye/skin disorder. From one eye in each subject, the following three swab specimens were collected and then stored at -20°C: 1) a swab of the lower eyelid skin, 2) a swab of the lower conjunctival sac, and 3) a swab of the lower eyelid MG secretion (i.e., meibum). DNA was later extracted from each specimen using the DNeasy PowerSoil kit (Qiagen), and microbiome analysis was carried out via the 16S rRNA method using the V1-V2 region. The MiSeq System (Illumina®) was then used for sequencing, and Qualitative Insights Into Microbial Ecology (QIIME™; QIIME Development Team) was used for analysis of the sequence data. For analysis of the acquired microbiome data, R statistical computing software (The R Foundation; www.r-project.org) was used.
Results :
The microbiome of the meibum was similar to that of the conjunctival sac, yet differed from that of the skin, even though the MG orifices were on the skin in the healthy subjects. The mean and median relative abundance of P. acnes in the meibum was 20.3% and 15.7%, respectively, in the younger-group subjects, while 10.7% and 3.5%, respectively, in the elderly-group subjects (p=0.0042, Mann-Whitney U test). In the meibum and the conjunctival sac, the diversity of the microbiome decreased (i.e., the microbiome became simple) with age. The mean and median diversity index (Shannon index) of the microbiome in the meibum was 2.77 and 2.94, respectively, in the younger-group subjects, while 1.78 and 2.01 in the elderly-group subjects (p=0.00087, Mann-Whitney U test). Sex difference in the microbiome was not significant in both the younger and elderly groups.
Conclusions :
The age-related changes in the microbiome in the conjunctival sac and meibum may affect the lipid metabolism of the MGs and homeostasis of the ocular surface.
This abstract was presented at the 2019 ARVO Annual Meeting, held in Vancouver, Canada, April 28 - May 2, 2019.