Composition of the gut microbiome in immune-mediated dry eye

Abstract

Purpose : Gut microbiome alterations have been associated with various autoimmune diseases. There is limited data, however, on relationships between gut dysbiosis and immune-related dry eye (DE). The aim of our prospective, cross-sectional study was to evaluate the gut microbial composition of individuals with early or late markers of Sjögren’s Syndrome (SS) compared to controls without DE.

Methods : We compared 20 individuals with positive early markers (anti-SP1, anti-CA6, anti-PSP IgG, IgA, andIgM) or late markers (anti-Ro/SS-A and anti-La/SS-B) of SS with no comorbid autoimmune diagnoses and 20 age- and sex-matched controls. Stool samples were collected and underwent deep RNA sequencing. The main outcomes measured were gut microbial composition and diversity.

Results : A total of 20 individuals with DE (mean age 61±13 years, Dry Eye Questionnaire-5 (DEQ-5) score of 15.2±3.4, Ocular Surface Disease Index (OSDI) score of 55.1±22.8, Schirmer of 7.1±5.2) were compared to 20 controls (mean age 59±12 years, DEQ-5 score of 4.8±3.8, OSDI score of 14.2±12.3, Schirmer of 21.9±9.1). No significant differences were observed in bacterial diversity (Shannon’s index, p=0.97) or overall community structure (Euclidean PERMANOVA, p=0.62). A total of 41 species were differentially abundant between groups (p<0.01). Among these, 34 were relatively more abundant in the case group, including 10 species of Lactobacilli and 4 species of Bifidobacteria. A relative depletion of 7 species was found in the case compared to the control group, notably Fusobacterium varium and Prevotella stercorea.

Conclusions : Differences in gut microbiome composition were found in individuals with early or late markers of primary SS compared to an age- and sex-matched control group. Further studies are needed to elucidate the role of gut dysbiosis on immune dysregulation and disease activity in the eye. Gut microbiome modulation as a potential therapy for DE, such as through probiotic use or fecal microbial transplant, is another area of further research.

This abstract was presented at the 2022 ARVO Annual Meeting, held in Denver, CO, May 1-4, 2022, and virtually.

 

Gut microbial composition at the genus level between the case and control groups.

 

Differentially abundant bacterial species between case and control groups. Circles on the left show significantly more abundant species in individuals with early or late SS markers, and on the right show significantly more abundant species in the control group (p<0.01, log2(fold change)>2.0). BaseMean compares the relative abundance of each species.