The human microbiome is composed of trillions of bacteria, viruses and fungi living in and on the human body. In 2007, the Human Microbiome Project characterized the microbiomes at five different body sites including the skin, gastrointestinal tract, oral cavity, nasal passages and urogenital tract in healthy human subjects, thereby improving the understanding of the microbial flora involved in human health and disease. Under normal physiological conditions, the microbiome is a homeostatic ecosystem with several essential functions. However, disruption of this homeostasis, called dysbiosis, is associated with multiple diseases.
These projects investigate associations of the gut microbiome with several eye diseases such as age-related macular degeneration and retinal artery occlusion. We are using whole-metagenome shotgun sequencing to characterize the intestinal microbiome of human subjects. Our state-of-the-art bioinformatics pipeline allows to dissect compositional and associated functional profiles of the microbes in the gut.
The human intestinal microbiome is dominated by the phyla Bacteroidetes and Firmicutes, followed by Proteobacteria and Actinobacteria. A shift in the Bacteroidetes to Firmicutes ration is often observed in association with several diseases.
Ocular surface microbiome
There are several known niches of the human microbiome including the skin or the oral cavity. Surprisingly, there is also a little known niche of the microbiome on the ocular surface. Its microbial composition, called the ocular surface microbiome, remains limited and still needs more investigation.
We are disentangling the interplay between the microbial composition on the ocular surface and proteins in tear fluid and potential impacts on ocular health and disease. These projects are performed in human subjects, but we are also employing animal models.
There is an interplay between antimicrobial components found in human tears and the composition of the ocular surface microbiome characterized using lid and conjunctival swabs. An imbalance between the ocular surface microbiome and the tear proteome may be associated with several eye diseases.