The current medical understanding that lungs are completely formed by the age of 3 years has now been challenged by researchers at the University of Leicester in a groundbreaking discovery. The international study of the growth and development of lungs, funded by the Wellcome Trust and published in the American Journal of Respiratory and Critical Care Medicine, was a collaboration of researchers from the Department of Infection, Immunity and Inflammation, University of Leicester, the Department of Physics and Astronomy, University of Nottingham, and the University of Bern.

For the first time, researchers presented a theory based on evidence that new air sacs (alveoli) are formed constantly. Until now, the majority of medical publications have taught that the development of alveoli starts approximately during the 6th months of pregnancy, and continue to increase in number until the age of about 3 years.

One of the study leaders, Dr. Manjith Narayanan from the University of Leicester, declared:

“It was believed that there was no further increase in the number of alveoli beyond that age, and that the existing alveoli just expanded as the lungs grew bigger until final adult size was reached. Our study has challenged this by suggesting that new alveoli continue to be formed as the lungs grow.”

The research involved more than 100 healthy volunteers between the ages of 7 to 21 years, who all underwent a series of breathing tests in Leicester, and subsequently had a special magnetic resonance (MR) scan in Nottingham, where they inhaled hyper-polarized helium and held their breaths.

According to Dr. Narayanan, a Clinical Research Fellow:

“The helium is hyperpolarized, which means that the molecules all line up in one direction and it then behaves like a magnetized gas. Within the scanner, we can measure how the magnetism decays, and this in turn depends on the size of the air sacs – alveoli – which contain the helium. The technique is safe and not painful or uncomfortable in any way.”

The study was described by senior lecturer at Leicester, Dr. Caroline Beardsmore:

“We studied small children, whose lungs contain approximately one liter of air, and full-grown adults with lung volumes of around four liters. We found very little difference in the size of the alveoli across everyone we studied. If the size of the alveoli are hardly changing, this can only mean one thing – as our lungs increase in size, we must be growing new alveoli.”

Emeritus Professor of Child Health at Leicester, Professor Mike Silverman, explains:

“This research has important implications. If we can continue to develop new alveoli beyond early childhood, going on through adolescence, there is the potential for lung repair following injury that was never realized before. Conversely, external factors (possibly including inhaled pollution) could have a negative impact on lung development. We now have the basis for looking at many factors with the potential to impact on lung health in the future.”

Written by Petra Rattue