World first study of infant and newborn airways microbiome throws light on origins of asthma

A world first study of the bacteria living in the lower respiratory tract of “healthy” newborns and young babies has shown that bacterial communities form within the first 2 months post-natally, and that these bacteria interact with the immune system in ways that could potentially influence its development.

The study, led by Professor Ben Marsland, a veski Innovation Fellow in the Department of Immunology and Pathology at Central Clinical School, Monash University, is published today in the journal Cell Host and Microbe.

Previous studies into the microbiota of the respiratory tract have relied on nasal swabs because samples from the lower respiratory region require an invasive procedure. As a consequence, very little is known about how the lung microbiome and immune cells develop in early life in humans.

Professor Marsland worked with his brother, Dr Colin Marsland, an anaesthesiologist in New Zealand, and a team of clinicians and scientists in Switzerland, to acquire samples from hundreds of newborns and young infants who as part of their standard care were intubated in neonatal care units or during elective surgery (to assist in breathing while under anaesthetic).

According to Professor Marsland, in this study the researchers used samples from the healthiest babies and children, who had no obvious clinical signs of respiratory problems, “because we wanted to discover how the lung microbiota forms during the first weeks and months of life in normal healthy infants,” he said.

The study found that a child has almost a full suite of microbes in the airways as early as two months old, “which is very fast and is mirrored by changes in the baby’s immune system,” Professor Marsland said. The makeup of the bacteria in a two-month old was similar to those in a healthy adult, he said.

Importantly the study found that gestational age, ie the ‘biological’ age at birth, is the key indicator for whether a newborn has a diverse microbiota in their lower airways. “This finding indicates that cross-talk between the developing immune system and the infiltrating microbes strongly influences how the lung microbiome develops,” Professor Marsland said.

In earlier work, published in Nature Medicine, Professor Marsland and his team have shown that formation of the lung microbiome educates the immune system of mice, and can protect them against the development of asthma.

“Although we don’t yet know how we could shape the lung microbiome of babies, data from our experimental models suggests this could be a powerful way of preventing asthma. Looking towards the future, we aim to develop approaches that could help translate our current knowledge into strategies to reduce the incidence of childhood asthma,” Professor Marsland said.

Source: Central Clinical School, Monash University
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