A1 Refereed original research article in a scientific journal

Skin microbiota and allergic symptoms associate with exposure to environmental microbes




AuthorsLehtimäki, Jenni; Sinkko, Hanna; Hielm-Björkman, Anna; Salmela, Elina; Tiira, Katriina; Laatikainen, Tiina, Mäkeläinen, Sanna; Kaukonen, Maria; Uusitalo, Liisa; Hanski, Ilkka; Lohi, Hannes, Ruokolainen, Lasse

PublisherNational Academy of Sciences

Publication year2018

Journal: Proceedings of the National Academy of Sciences of the United States of America

Journal name in sourceProceedings of the National Academy of Sciences

Volume115

Issue19

ISSN0027-8424

eISSN1091-6490

DOIhttps://doi.org/10.1073/pnas.1719785115

Web address https://www.pnas.org/doi/full/10.1073/pnas.1719785115


Abstract

A rural environment and farming lifestyle are known to provide protection against allergic diseases. This protective effect is expected to be mediated via exposure to environmental microbes that are needed to support a normal immune tolerance. However, the triangle of interactions between environmental microbes, host microbiota, and immune system remains poorly understood. Here, we have studied these interactions using a canine model (two breeds, n = 169), providing an intermediate approach between complex human studies and artificial mouse model studies. We show that the skin microbiota reflects both the living environment and the lifestyle of a dog. Remarkably, the prevalence of spontaneous allergies is also associated with residential environment and lifestyle, such that allergies are most common among urban dogs living in single-person families without other animal contacts, and least common among rural dogs having opposite lifestyle features. Thus, we show that living environment and lifestyle concurrently associate with skin microbiota and allergies, suggesting that these factors might be causally related. Moreover, microbes commonly found on human skin tend to dominate the urban canine skin microbiota, while environmental microbes are rich in the rural canine skin microbiota. This in turn suggests that skin microbiota is a feasible indicator of exposure to environmental microbes. As short-term exposure to environmental microbes via exercise is not associated with allergies, we conclude that prominent and sustained exposure to environmental microbiotas should be promoted by urban planning and lifestyle changes to support health of urban populations.



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