A team of Columbia University researchers has found the first direct evidence of a link between prenatal vitamin A deficiency and postnatal airway hyperresponsiveness – a hallmark of asthma.
The vitamin A deficiency can cause profound changes in the smooth muscle that surrounds the airways – causing the adult lungs to respond to environmental or pharmacological stimuli with excessive narrowing of airways, say Columbia University Medical Center (CUMC) investigators led by Wellington V. Cardoso.
“Researchers have long wondered what makes some people more susceptible than others to developing asthma symptoms when exposed to the same stimulus,” added Cardoso, faculty member in the division of pulmonary allergy clinical care medicine.
Our study suggests that the presence of structural and functional abnormalities in the lungs due to vitamin A deficiency during development is an important and under-appreciated factor in this susceptibility, he stressed.
Previous studies had shown that retinoic acid (RA) – the active metabolite of vitamin A – is essential for normal lung development. The researchers used a mouse model in which they could control when and in what amount vitamin A would reach the developing foetus through maternal diet.
They timed the vitamin A deficiency to the middle of gestation, coinciding with the period of formation of the airway tree in the foetus. Foetuses that were deprived of vitamin A were found to have excess smooth muscle in the airways, compared with control groups.