Are gut microbes in infancy associated with later atopic wheeze?

Published online: December 11, 2017

Asthma is the most prevalent childhood chronic disease in the world. Despite its high and rapid increase in incidence, the actual causes of asthma upsurge remain unknown. Recent findings implicate the large community of microbes that inhabit the human intestine (gut microbiota) during early life. Previous work has provided strong evidence for the presence of a critical window, early in human life, during which changes in the gut bacterial microbiome influence the immune alterations that lead to atopy and asthma. All of these studies have been performed in industrialized settings.

In a recent study published in The Journal of Allergy and Clinical Immunology (JACI), Arrieta and colleagues aimed to determine if microbial alterations in early infancy can also be detected in a non-industrialized setting, where microbial conditions are known to differ from other populations studied thus far. The authors used data collected from 97 babies recruited in the ECUAVIDA birth control study in rural Ecuador. Twenty-seven of these babies developed atopic wheeze by 5 years of age, a strong risk factor for asthma, whereas the rest remained healthy.

The researchers analyzed the bacterial and eukaryotic (fungi, protozoans, etc) microbiota from feces collected at 3 months of age, by sequencing the 16S and 18S rRNA genes. They also measured the concentration of short-chain fatty acids, an important group of bacterial metabolites readily produced in the gut. Several environmental and lifestyle factors were also studied for their influence in disease risk.  

The authors revealed that there were marked gut microbial alterations associated with subsequent atopic wheeze, most of which were fungi. These alterations differed from the ones previously reported in Canadian infants. However, one common finding was a decrease in acetate (a short-chain fatty acid produced by gut bacteria) in babies that later developed atopic wheeze. Environmental factors significantly associated with atopic wheeze were birth by Caesarean section and increased number of respiratory infections during the first year of life. These findings support the importance of the gut microbiota during the first 100 days of life on the development of asthma and provide additional support for considering the modulation of the gut microbiome as a primary asthma prevention strategy.

The Journal of Allergy and Clinical Immunology (JACI) is an official scientific journal of the AAAAI, and is the most-cited journal in the field of allergy and clinical immunology.

Close-up of pine tree branches in Winter Close-up of pine tree branches in Winter