Thyroid hormone, or drugs based on the hormone, may be effective against pulmonary fibrosis—a chronic and progressive lung disease—according to a new study. Researchers led by Naftali Kaminski, MD, chief of pulmonary critical care and sleep medicine and the Boehringer Ingelheim Pharmaceuticals, Inc., Endowed Professor of Medicine (Pulmonary), first found that a protein involved in activating thyroid hormone was increased in the lungs of people with a severe form of pulmonary fibrosis. This led the investigators to try the effects of aerosolized delivery of thyroid hormone in two different mouse models of lung fibrosis.
Mice treated with aerosolized thyroid hormone, as well as a small molecule that mimics the effect of the hormone, showed significant resolution of the fibrosis in their lungs and survived longer compared to untreated mice. The hormone, the team discovered, improved the function of energy-generating mitochondria in the cells that line the lungs. This effect, which may shield the cells from damage, may be important in the resolution of fibrosis. The results, reported on Dec. 4 in Nature Medicine, suggest that aerosolized thyroid hormone should be developed for pulmonary fibrosis in people.