When taking medication during an attack, patients with the most severe form of asthma produce substances in their airways that prevent the treatment from working.
- Researchers have discovered a biological mechanism in severe asthmatics that blocks the action of treatments.
- Asthma, a chronic inflammation of the bronchial tubes which manifests itself in attacks, in the form of wheezing and breathing difficulties, affects more than 4 million people in France.
It’s a long-standing mystery that has just been solved by scientists. A study published in journal Science Translational Medicine has made it possible to better understand why some asthmatics react badly to treatment when the majority of asthmatics are well controlled.
Indeed, in about 5% of cases severe forms persist, indicates Inserm. And corticosteroids used to reduce airway swelling and irritation in people with moderate asthma often don’t work in people with severe asthma.
Growth factor secretions
Researchers have found that inhaled steroids in patients with severe asthma promote the secretion of growth factors that stimulate cell proliferation – fibroblast growth factor (FGF) and granulocyte colony growth factor (G-CSF ) – in the cells of the wall of the respiratory tract, called epithelium.
They compared samples of bronchial airway epithelial cells (BAEC) that had been exposed to inhaled corticosteroids and had been collected from three groups: those with severe asthma, those with moderate asthma and healthy volunteers.
Against the action of corticosteroids
By performing genetic analysis to determine which genes had been activated in the BAECs, the scientists were able to observe that the growth factors FGF and G-CSF had only been expressed in the cells of patients suffering from severe asthma.
“In the case of an asthma attack in patients with severe asthma, the growth factors identified in the cells lining the main connecting airways act directly against the action of corticosteroids. Study results suggest that different cellular pathways are at work in the cells of patients with severe asthma, including those involved in inflammationsaid author Reynold Panettieri Jr, professor of medicine at Rutgers Robert Wood Johnson Medical School.