Microbes in the lungs prevent asthma

Study: Microbes in the lungs protect against asthma

05/15/2014

It may be decided in the first few weeks after birth, whether somebody will later suffer from asthma or not. This is indicated by the results of a study from Switzerland. Thus, microbes in the lungs in mice protect against allergic asthma. Researchers hope to prevent asthma in the future.

Lung microbes protect against allergic asthma
Already in the first weeks after the birth could decide whether somebody will later fall ill with asthma or not. At least this is suggested by the results of a study in mice supported by the Swiss National Science Foundation (SNSF). They would suggest that microbes in the lungs train the neonatal immune system. The lungs were considered germ-free and sterile for a long time. Only recently did it become clear that our respiratory system, like the intestine and the skin, is colonized by bacteria. Researchers led by Benjamin Marsland from the University Hospital CHUV in Lausanne, Switzerland, have now shown in experiments with mice that these lung microbes protect against allergic asthma.

Germ-free mice remain susceptible to lifelong asthma
The scientists, their results in the journal „Nature Medicine“ Published mice exposed an extract of house dust mites. Just born mice, in contrast to older animals, developed a strongly increased allergic reaction to the extract. This is because the lungs of newborn mice are not yet colonized by microbes that make the immune system of the mice less susceptible to allergic reactions. The researchers found that this colonization and adaptation process takes place in the first two weeks of the mouse's life. Keeping young mice completely free of germs left them susceptible to asthma for a lifetime and even responded to the dust mite allergens with overreaching immune responses even in advanced mouse age.

Parallels between human and mouse
The team of scientists is currently investigating whether lung microbes also provide healthy airways in humans. Pilot studies in babies in Switzerland and New Zealand would indicate that there are indeed parallels between human and mouse. However, further studies would have to follow to identify potential mechanisms in humans. „In early development, there seems to be a window of opportunity for deciding whether an individual will suffer from asthma later in life or not“, so Marsland. Scientists and physicians have focused on the topic of asthma so far mainly on the course of the disease and possible immediate triggers. „But we probably have to look much earlier at the newborns.“

Fiber rich diet can protect against allergic asthma
The researcher now wants to find out what the window of opportunity for the development of the immune system in childhood is. Marsland hopes the new knowledge will one day help prevent asthma. Possibly by pregnant women to increased fruit and vegetable consumption are stopped. It is only recently that Marsland has shown that diets rich in fiber can also protect against allergic asthma by altering the microbial flora. This protection could possibly be transferred to the newborn. In addition to whole-grain products, the residual product bran, which is produced during flour production, also counts as a fiber-rich diet. Many fibers are also found in beans, peas, spinach, carrots, apples, oranges or jacket potatoes.

Farm children are less likely to suffer from allergies
German scientists have also pointed to the positive influence of microbes in the past. More than ten years ago, the Marburg allergist Harald Renz discovered why farm children are much less likely to suffer from allergies. Their risk of hay fever or asthma is only half that of children growing up in an urban environment. The researchers came to the conclusion that this is due to the microbes, which occur in large numbers on farms. These microorganisms would eliminate the genes that trigger allergic reactions. (Sb)