Posted on 9 October 2019
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A study of newborn babies identified a compound produced by gut bacteria that appears to predispose development of allergies and asthma in certain infants.
Many infants at risk of childhood atopy and asthma exhibit perturbation of the gut microbiome and metabolic dysfunction. Analysis of faecal samples from two independent birth cohorts revealed that bacterial epoxide hydrolase (EH) genes are more abundant in the gut microbiome of 1-month old babies who develop atopy and/or asthma during childhood.
"We have discovered a specific bacterial lipid in the neonatal gut that promotes immune dysfunction associated with allergic asthma and can be used to assess which babies are at risk of developing the disease in childhood." said Susan Lynch, senior author of this study.
Three of these bacterial EH genes specifically produce 12,13-diHOME, a pro-inflammatory lipid that was shown in mice to reduce the number and activity of regulatory T (Treg) cells that normally suppress allergic inflammation. The number of copies of these three bacterial EH genes or the concentration of 12,13-diHOME in infant stool samples predicted which infants went on to develop allergy by age two or asthma by age four.
"This is likely just one component of a complex microbiome-immune interaction in young infants that promotes allergy and asthma development in childhood," Lynch said. "But it is a first step towards a more mechanistic understanding of the suite of microbial products that increase susceptibility to allergies and asthma during childhood."
Lynch’s team is optimistic that “this finding paves the way for early-life gut microbiome interventions to prevent these diseases from developing." They plan to develop screening protocols to identify newborns at high risk for asthma and allergy based on the presence of 12,13-diHOME and other microbial molecules in their stool.