Studies elucidate the mechanism behind protective farm effects on childhood asthma

Review by Emily Henderson, Bachelor of ScienceNovember 2, 2020

Asthma affects millions of children already young. Children raised on farms are at a lower risk of developing asthma than children who do not live on farms. Little is known about the mechanism behind this protective farm effect on childhood asthma. Helmholtz Zentrum München and a group of researchers at Dr. von Hauner Children’s Hospital at Ludwig Maximilian University Munich (LMU) have shown how the intestinal flora of children is involved in the protective process.

We are born in an environment full of small creatures called microbiota. Within the first minutes and hours of our lives, they not only begin to challenge, but also begin to educate our immune system. The largest immune organ is our intestine, and the maturation of the immune system is closely linked to the maturation of the colony-forming bacterium Gut flora. After severe perturbation and maturation in the first year of life, the composition of the intestinal flora gradually stabilizes and accompanies our lives. Previous studies by Munich scientists have shown that diverse environmental microbiomes can protect against asthma. This was especially noticeable for children on the farm. The question here was whether this effect could be due to the early maturation process of the gut microbiota.

Farm life promotes maturation of the intestinal flora of children Researchers have participated in PASTURE (a European birth cohort that has been operating for almost 20 years now), partly on a traditional farm for 2-12 months. We analyzed fecal samples from more than 700 babies raised in the European Commission, funded by the European Commission.

“We found that a relatively large proportion of the protective farm effect on childhood asthma is mediated by the maturation of the intestinal flora in the first year of life,” said Dr. Martin Depner, biostatistician at Helmholtz Zentrum München. I conclude that. Farmer children suggest that they interact with the gut flora and are in contact with environmental factors that lead to this protective effect, perhaps the environmental microflora. “

Researchers had predicted the effects of nutrition on the maturation of the gut flora, but were surprised to discover the strong effects of farm-related exposures, such as staying in a zoo. This emphasizes the importance of the environment for protective effects. In addition, vaginal delivery and breastfeeding promoted the protective microbiome in the first two months of life.

In addition, researchers found an inverse correlation between asthma and measured fecal butyric acid levels. Butyric acid is a short-chain fatty acid known to be effective in preventing asthma in mice. Researchers have concluded that intestinal bacteria such as rosebria and coprococcus, which can produce short-chain fatty acids, may also help prevent asthma in humans. Children with a mature gut flora had higher levels of these bacteria (Rosebria and Coprococcus) than other children.

“Our study provides further evidence that the gut can affect lung health. Mature gut microbes containing high levels of short-chain fatty acids breathe in the children of this study. It has had a protective effect on organ health, which suggests a human-related gut-lung axis idea, “said Dr. Markus Ege, a professor of clinical respiratory epidemiology at von Howner Children’s Hospital. “But this also means that the immature gut flora can contribute to the development of the disease. This means that the gut flora is very plastic and susceptible to alteration 1 after birth. It emphasizes the need for a yearly preventive strategy. “

Probiotic preventive strategy researchers have demonstrated that the protective effect of asthma depends not only on a single bacterium, but on the maturation of the entire gut flora. This finding casts doubt on the approach of using a single bacterium as a probiotic for the prevention of asthma. Probiotics should be tested for their persistent effects on the compositional structure of the gut flora and their early maturation in life.

Further Research on Milk The nutritional aspects analyzed in this study may serve as a preventative strategy, such as milk consumption. However, untreated milk is not recommended due to the risk of life-threatening infections such as EHEC. Scientists at Dr. von Hauner Children’s Hospital are currently conducting clinical trials on the effects of minimally processed but microbiologically safe milk to prevent asthma and allergies (MARTHA trial). ).