Composition and diversity of meibum microbiota in meibomian gland dysfunction and its correlation with tear cytokines levels

Abstract

Meibomian gland dysfunction (MGD) is commonly caused by obstruction of the terminal meibomian gland duct, which is associated with alterations in the quantity and quality of the meibum. This may affect the composition of meibum microbiota, causing aberrant cytokine production, epithelial hyperkeratinization, and meibomian gland blockage. This cross-sectional study included 44 patients with moderate to severe MGD and 44 healthy controls, to determine the meibum microbiota by next-generation sequencing (NGS) and its association with tear cytokines levels. We observed reduced bacterial diversity in the meibum microbiota of patients with severe MGD. Significantly higher abundance of Bacteroides and Novosphingobium, and substantially higher IL-17A levels were detected in the MGD group. Despite being a biomarker for MGD, Bacteroides showed no correlation with IL-17A but a moderate negative correlation with IL-1β. The relationship between core meibum microbiota and tear cytokines levels remains to be clarified. However, a higher abundance of Bacteroides and Novosphingobium is speculated to has a key role in the pathophysiology of MGD. To reduce the risk of this particular bacterial infection, timely diagnosis and treatment for MGD are recommended, especially before ocular surgery.