Born after just 23 of the normal 40 weeks of pregnancy, the extremely preterm baby is small enough to fit in the palm of my hand and weighs just one and a quarter pounds. I am a neonatologist, a physician that cares for these preterm babies in intensive care. Most of these preterm infants, particularly the smallest and sickest who require oxygen to help them breathe, are at high risk of developing lung inflammation and scarring.
This early damage will lead to a chronic lung disease called bronchopulmonary dysplasia. Bronchopulmonary dysplasia can be one of the most severe and long-lasting complications of being a preterm baby. Many require oxygen for years and often have severe asthma-like episodes during which they are hospitalized for difficulty breathing.
Bronchopulmonary dysplasia affects many of the tiniest preterm babies that I care for and often leads to severe long-term disability. But it’s tricky to prevent preterm babies from developing bronchopulmonary dysplasia, and the situation is a bit of a Catch-22. That is because oxygen and breathing machines, which are essential for keeping these babies alive, also increase the likelihood of developing bronchopulmonary dysplasia. This dilemma has inspired my research into lung disease in preterm babies to discover new ways of preventing bronchopulmonary dysplasia.
The gut-lung axis
In newborns, research into asthma and pneumonia has indicated that the microbial communities, known as the microbiome, that live inside the human gut can influence inflammation – the response of the body to pathogens or cellular damage – in their host. This may happen because of changes in the host immune system, which in turn may shape the course of lung diseases that result from inflammation.
This recently discovered connection between the gut microbes and lung health or disease is called the gut-lung axis, and it may reveal new ways to treat lung diseases.