Retinoic acid, a form of vitamin A, appears to cure the lung disease emphysema in mice, according to a new study that suggests the vitamin could one day provide a treatment for the disease in humans, currently without cure.
Emphysema is the result of long-term damage to the alveoli of the lungs, caused mainly by smoking. When the alveoli in the adult lung are destroyed, there is a loss of gas exchanging surface area, initially leading to mild breathlessness but in the end leaving patients struggling to breathe.
However Malcolm Maden and his colleagues from the MRC Centre for Developmental Neurobiology at King's College London proposed that if the alveoli could be induced to regenerate then this disease could be cured.
For the study, published in the January issue of the European Respiratory Journal (vol 23, no 1), the researchers bred mice without alveoli. When these mice become adults they have the histological hallmarks of emphysema with greatly enlarged air spaces and a massive loss of gas exchanging surface area. When these mice were given retinoic acid, they found the number and size of alveoli returned to normal and their lung function was restored.
Retinoic acid is a very important component of developing embryos and is known to induce regeneration in other systems, such as the skin. The researchers believe that the molecule may trigger key genes into action, helping the alveoli to recover.
The work confirms data obtained recently in the USA using a different model system, said the researchers.