By sampling the gut microbiome early in life, researchers have shown that four types of commensal microbes, and the metabolites those microbes produced, were present at lower levels in children at high risk of developing asthma when those children were 3 months old.

By the time the high-risk cohort had turned 1, the microbiome had caught up with that of normal-risk children. The risk of developing asthma, however, appeared to remain elevated.

Co-author Stuart Turvey, a pediatric immunologist at the University of British Columbia Children's Hospital, told reporters that the findings, which appear in the Sept. 30, 2015 issue of Science Translational Medicine, illustrate a theme that is "important and not so surprising to pediatricians . . . how important that very early life is."

They could also lead to new ways to diagnose and perhaps prevent asthma, which has been sharply on the rise in developed countries for reasons that are still unclear, but are thought to include a reduction in exposure to microbes.

Finally, they are further evidence of the importance of the microbiome. If more evidence is needed.

The microbiome's effects on the health of its host, and how often that effect is for better rather than for worse, is firmly established as one of the biggest scientific areas of inquiry to open up in recent years.

Jeffrey Gordon, director of the Center of Genome Sciences and Systems Biology at Washington University School of Medicine, was named a 2015 Thomson Reuters Citation Laureate – that is, a researcher whose work makes him a candidate for a Nobel Prize – "for demonstrating the relationship between the human gut microbiome and physiology, metabolism and nutrition."

Scientific insights into the microbiome's importance have yielded a crop of start-ups trying to develop products based on the research.

Some companies, such as Vedanta Inc., Rebiotix Inc. and Seres Therapeutics Inc., are working on delivering the bacteria themselves. Others, like Enterome Biosciences SA, Second Genome Inc. and Symberix Inc., are working on small molecules that target the microbiome. (See BioWorld Insight, June 31, 2014.)

The work presented this week by Turvey and his colleagues is part of the Canadian Healthy Infant Longitudinal Development (CHILD) Study, a long-term study of more than 3,000 children that, according to the project's website, "will examine the influences of genetic predisposition and environmental factors on children's development," with an emphasis on allergies and asthma.

For the study now published in Science Translational Medicine, the team looked at 319 of those children, 22 of whom were judged to be at high risk of developing asthma based on allergies and wheezing.

Co-author Brett Finlay, distinguished professor at the University of British Columbia, told reporters, that "four microbes in these 22 [infants] that were lower" than normal when the babies were about 3 months old, "indicating these four microbes may be preventative or decreased in the risk of asthma."

When the team treated germ-free mice with those four bacteria – Lachnospira, Veillonella, Faecal bacterium, and Rothia – airway inflammation in the adult offspring of treated mice was decreased, showing that the bacteria were protective against asthma across generations.

The exact therapeutic implications of the work now published in Science Translational Medicine remain to be worked out.

For one thing, the children in the study are still of preschool age, and so the final count of who will develop asthma is not in yet.

But so far, the team's predictions of who is at risk appear to be holding up. Eight of the 22 high-risk children have been diagnosed with asthma.

Turvey said that the "low-hanging fruit" in terms of practical applications would be to identify such children early on through fecal microbiome testing, which would allow for earlier treatment of high-risk individuals with available options.

What he termed "the stretch goal" is to treat such children very early on to prevent asthma from developing in the first place. Because the differences between high-risk and lower-risk children disappeared by the time the children were 1 year old, replacing the missing bacteria would only be expected to have an effect if it were done very early in life, if at all.

Turvey emphasized, though, that "we're not ready for that yet. We know very little about these bacteria." A successful treatment might consist of a cocktail of all four bacterial types, one or more of them, or the metabolites they produce.

It's less likely that anything can be gained by treating the babies with currently available probiotics. A clearly skeptical Turvey said "one of the issues is that we're starting to discover this massive universe of bacteria, and the bacteria that are often presented in the probiotics we can buy at the health food store or the supermarket . . . don't include this flavor combination that we've identified."