A study conducted by Monash University has found that microbial fermentation of dietary fibre in the gut can protect against allergic skin disease.
Published in Mucosal Immunology and exploring the emerging gut-skin axis, this research could potentially lead to novel treatments to prevent or treat allergies.
Professor Ben Marsland from the Central Clinical School’s Department of Immunology worked with Swiss researchers from the University of Lausanne, led by Aurelian Trompette, finding that the fermentation of fibre in the gut by bacteria and subsequent production of short-chain fatty acids, in particular butyrate, protected against atopic dermatitis in mice.
It is well established that the microbiome of the gut shapes the immune system, though the influence it has on the skin is much less explored.
“Previous work from our group, and others, has focused on the local health benefits of short-chain fatty acids in the gut, as well as at distal sites such as the lung and cardiovascular system,” Professor Marsland says.
“We wondered if this might also extend to the skin, which is an area that has not really been investigated. People speculate that diet can influence skin health, but there is not a great deal of science behind this,” he says.
Mice studied in the research were fed a diet high in fermentable fibre or given purified short-chain fatty acids.
“This treatment was profoundly protective against allergic skin inflammation,” says Professor Marsland.
Butyrate, a prominent short-chain fatty acid, was labeled with isotopes and tracked in the bodies of the mice, where it took only minutes to reach the skin. This enhanced the metabolism of keratinocytes, priming them to mature and produce key structural components required for a healthy skin barrier.
“The upshot of this was that the skin barrier was fortified against allergens – we were using house dust mite allergens – that would normally penetrate the skin barrier, activate the immune system and start an allergic reaction in these models,” Professor Marsland said.
“It turns out the immune system was secondary to this skin barrier function.”
Actively improving the skin barrier could have protective effects against environmental exposures that cause allergies and perhaps other skin diseases underpinned by a damaged or weak skin barrier.
Professor Marsland says that these short-chain fatty acids could be administered orally or directly onto the skin as a cream, bypassing the gut.
Among possible uses for these findings are determining whether or not this could help children at risk of developing skin allergies that cascade toward food allergies and asthma.
The project was conducted between Melbourne and Swiss-based researchers across five to six years.
To read the full paper, visit nature.com/mi and search ‘gut-derived short-chain fatty acids modulate skin barrier integrity by promoting keratinocyte metabolism and differentiation’.
