Fecal microbial transplantation (FMT) can be safely administered to patients with immune-mediated dry eye (DE), although the most effective route and the frequency of administration are still unclear, according to research published in the American Journal of Ophthalmology.
A team of investigators conducted an open-label, nonrandomized clinical trial to determine the safety of FMT in patients with DE.
A total of 10 patients (mean age, 60.4 years; 30% men; 50% White and 50% Hispanic) with full (50%) or early (50%) Sjögren syndrome criteria were administered 2 FMTs from a healthy donor delivered via enema 1 week apart.
The primary outcome of the study was safety. Gut microbiome profiles, DE metrics, and T-cell profiles in blood were analyzed at baseline, and at 1 week, 1 month, and 3 months post-FMT.
Compared with the donor, patients had significantly different gut microbiome profiles at baseline, including higher mean diversity indices. Participants experienced a decreased abundance of the following genera compared with the donor: Faecalibacterium, Prevotella, and Ruminococcus. Conversely, the genera Alistipes, Streptococcus, and Blautia were found to be elevated in participants compared with the donor.
T-effector percentages were found to be within the normal range for the majority of participants; however, there was a positive correlation between T effector cells (Th1: r =0.76, P =.01; Th17: r =0.83, P =.003) and T regulatory cells (CD25: r =0.66, P =.04; FoxP3: r =0.68, P =.03) and DE symptom severity. Investigators noted a positive relation between corneal staining and T effector cells with regards to DE signs, and a negative relation between corneal staining and T regulatory cells, although these results were not statistically significant.
Following FMT, 8 participants had gut microbiome profiles that moved closer to the donor’s profile. No adverse events were reported with FMT. At the follow-up times, collectively, gut microbiome profiles were found to be more similar to the original recipient’s microbiome than the donor’s, although some phyla, classes, and genera operational taxonomic units were closer to the donor’s compared with recipient baseline profiles at 3 months follow-up. At 3 months after FMT, half of the participants reported improvements in dry eye symptoms.
“Despite the fact that symptoms and signs of DE were mostly unchanged after FMT in our population, gut microbiome manipulation remains a potential future therapy for immune-mediated DE,” according to the study. “However, given the complexity of FMT, gut microbiome manipulation via alternative methods such as prebiotics and probiotics should be explored with specific deficits in the DE microbiome targeted. Future studies are needed to focus on these lines of investigation.”
Watane A, Cavuoto KM, Rojas M, et al. Fecal microbial transplant in individuals with immune-mediated dry eye. Am J Ophthalmol. Published online June 29, 2021. doi:10.1016/j.ajo.2021.06.022