The gut-skin connection is a key factor in atopic dermatitis (AD), according to a new review study in the International Journal of Molecular Sciences.
“Besides being responsible for 70% of immune system regularization, for maintaining skin barrier integrity and the structure of the gastrointestinal tract, and for controlling nutrient absorption and energy balance, the gut microbiome is directly connected to the skin via what’s known as the gut-skin axis,” says study author Sabri Saeed Sanabani, a researcher at the Institute of Tropical Medicine São Paulo, Brazil, in a news release.
Studies have reported an increased abundance of Clostridium difficile, Escherichia coli, and Staphylococcus aureus, as well as a decreased abundance of bacteria that produce short-chain fatty acid (SCFAs), such as Bifidobacteria and Bacteroides, in the gut microbiome of AD patients compared to healthy controls. A reduction in levels of SCFAs is often associated with intestinal inflammation in otherwise healthy subjects, the researchers note.
Genome-wide association studies (GWAS), focusing on the identification of associations between genetic variants and important phenotypes, have found several markers that correlate with susceptibility to AD and its progression, including mutations in the filaggrin gene (FLG) that are the most well-established risk factor for AD. Whether gut microbiome alterations are genetically determined is unknown, however.
While environmental factors also remain mostly unknown, scientists think that allergens, irritants, pollution, and exposure to microbes contribute to skin barrier impairment and gut microbiome dysbiosis.
The review also covers promising therapeutic approaches, such as those targeting epigenetic alterations and modulation of changes to gut microbiome diversity via diet, probiotics, and prebiotics, as well as fecal transplants.