Intestinal bacteria in infants: a weapon against asthma

Newborn babies could be protected for life against asthma if their intestinal flora acquires certain types of bacteria for the first three months, researchers have determined, paving the way for preventive treatment against this chronic respiratory allergy increased sharply.

Asthma, which quadrupled in population since the 1950s, affects up to 20% of children in western countries, say the scientists Wednesday in the US medical journal Science TranslationalMedicine.

“This study shows that four types of intestinal bacteria play a role in the prevention of asthma, but only very early in life, at the time of the formation of the immune system of the new-born,” says Brett Finlay, a professor of microbiology at the University of British Columbia in Canada and one a lead author.

This discovery opens the way for the development of preventive treatments for probiotic infants may protect them against asthma, say researchers. It could also help to design tests to predict in young children who are most likely to suffer from asthma.

For their research, the scientists analyzed samples of fecal 319 children.

Analyses of these samples revealed a deficiency of four types of intestinal bacteria in children three months later presented a greater risk of suffering from asthma.

Most infants naturally acquire these four strains of bacteria (Faecalibacterium, Lachnospira, Veillonella and Rothia), but we still do not know why others do not.

The researchers however found less difference in the rate of these bacteria in the intestinal flora in children younger than one year, which indicates that the first three months of life are critical for the development of the immune system.

The researchers were able to confirm these observations with experiments on mice, discovering that rodents that these four types of bacteria had been inoculated at birth had significantly less severe symptoms of asthma.

“Too clean environment” 

“This discovery could lead to new ways to prevent us this potentially fatal disease for many children,” said Dr. Stuart Turvey, an immunology specialist pediatrician at the Vancouver Children’s Hospital.

“It shows that there is possibly one hundred days after the birth window for therapeutic intervention to protect newborns against asthma,” he says.

More extensive research is needed to confirm this finding and understanding how these bacteria act on asthma development mechanism, said the pediatrician. A study is already underway in Ecuador.

“These intestinal bacteria produce metabolites, chemicals that are apparently very important to train the immune system in the first two or three months of life,” he told AFP.

The role of intestinal bacteria to fight against allergies has been highlighted by previous research, he says.

A study published in the US late 2014 has revealed that certain intestinal bacteria protected mice against food allergies, especially peanut, whose causes remain unknown.

“This work reinforces the hypothesis that our environment is too clean” destroying useful bacterial agents, said Dr. Turvey, citing a study conducted in Germany has found a lower risk of asthma in children raised on a farm.

Reinforcing this hypothesis, he noted that infants treated with many antibiotics during their first year of life are also more prone to asthma as those who are born by Caesarean section, they are not exposed to the same bacteria those coming to the world through the vaginal canal.

The human body has trillions of bacteria that are essential for health, the researchers said.There are ten times as many bacteria cells than human cells in our body.