Modifying gut microbiome may eventually prevent asthma in infant boys

29 Nov 2017 --- The family risk for asthma – typically passed from mothers to babies – may involve the microbes found in a baby's digestive tract. This is according to a new University of Alberta study, funded by the Canadian Institutes of Health Research (CIHR) and AllerGen and published in the European Respiratory Journal.

Maintaining a healthy gut microbiome, the community of microorganisms or bacteria that live in the digestive tracts of humans, has been linked recently with a number of health benefits. For example, it may help to track and treat Parkinson’s and Alzheimer’s according to studies presented at Neuroscience 2017, the annual meeting of the Society for Neuroscience, and it has also been linked to preventing MS and hypertension.
 
AllerGen investigator and UAlberta microbiome epidemiologist Anita Kozyrskyj led a research team which found that Caucasian baby boys born to pregnant mothers with asthma – who are typically at the highest risk for developing asthma in early childhood – were also one-third as likely to have a gut microbiome with specific characteristics at three to four months of age.

“We saw a significant reduction in the family of microbes called Lactobacillus in Caucasian baby boys born to pregnant women who had asthma, and this was especially evident if the asthmatic mother had allergies or was overweight,” says Kozyrskyj, senior author of the study and researcher on the gut microbiome.

First results to show link, but caution urged
These findings provide the first evidence that maternal asthma during pregnancy may be associated with changes in an infant's gut microbes, according to Kozyrskyj.

“Our discovery, with more research, could eventually lead to a preventative approach involving modifying the gut microbiome in infants to reduce the risk,” she explains.

She also cautions, however, that it is too early for parents to be seeking probiotic treatments for their infants to address this particular concern.

Kozyrskyj and her team's research involved over 1,000 mothers and their infants participating in AllerGen's CHILD Study, a national population-based birth cohort.

Kozyrskyj said that she and her team were motivated to study the gut microbiome-asthma link by the well-established fact that maternal asthma affects infant birth weight in a sex-specific manner.

“The Caucasian male fetus is more likely to have a lower birth weight in response to maternal asthma, so we knew there were already sex-based differences occurring, and we decided to study them further,” Kozyrskyj notes.

The study also found that maternal asthma had an impact on the gut bacterial profile of baby girls, but in a different way.

“Baby girls were more likely to have higher amounts of bacteria in the Bacteroidaceae family, which are important for maintaining the mucus barrier that protects gut cells from damage by harmful substances,” says Kozyrskyj.

“We speculate that this may protect baby girls from developing asthma in early life. On the other hand, changes to bacterial composition specific to baby girls may increase their risk for developing asthma during puberty, when the gender switch in asthma occurs,” Kozyrskyj adds.

The study, “Sex-specific impact of asthma during pregnancy on infant gut microbiota,” can be found here.