Overview: Idiopathic Pulmonary Fibrosis
Idiopathic pulmonary fibrosis (IPF) is a chronic, progressive, fibrotic disorder of the lower respiratory tract that typically affects adults over the age of 40.1 It is the most common interstitial lung disease seen by pulmonologists.
- In the US, the prevalence of IPF ranges from 13.2-27.9 per 100,000 for women and 20.2-63.0 per 100,000 for men.1
- As a result of progressive fibrosis, patients with IPF experience deteriorating lung function and severe dyspnea, which can take on a slow, rapid, or mixed clinical course that ultimately ends in death.2
- The median survival for patients is estimated to be between 2.5 and 3.5 years from diagnosis.2
- Several pulmonary and non-pulmonary comorbidities are associated with IPF, including emphysema, lung cancer, cardiovascular disease, gastroesophageal reflux disease, and depression.3
- Because age is a major risk factor and predictor of IPF, the disease prevalence is expected to rise with the aging population.2
- There is no cure for IPF and therapeutic options currently remain limited.3
The exact cause of IPF is not known, but it is thought to be the result of abnormal repair of alveolar injury.2 Results from several studies suggest that the Wnt signaling pathway is involved in the processes that drive lung inflammation and fibrosis.
- Wnt signaling is essential for lung development, but in healthy adult lungs Wnt signaling is inactivated.4 However, in the lungs of IPF patients, overexpression of Wnt proteins and activated Wnt signaling have been found in the alveolar epithelium and fibroblasts.2,5
- This activation of Wnt signaling may represent an abnormal reactivation of developmental stem cell pathways that lead to inappropriate tissue remodeling2, and suggests that targeted inhibition of the Wnt pathway in the lungs of patients with IPF may have a therapeutic benefit.
- Ley B & Collard HR. Epidemiology of idiopathic pulmonary fibrosis. Clin Epidemiol. 2013;5:483-92.
- King TE, Pardo A, Selman M. Idiopathic pulmonary fibrosis. Lancet. 2011;378(9087):1949-61.
- King CS & Nathan SD. Idiopathic pulmonary fibrosis: effects and optimal management of comorbidities. Lancet Respir Med. 2016; Sep 2:[Epub ahead of print].
- Beers MF & Morrisey EE. The three R’s of lung health and disease: repair, remodeling, and regeneration. J Clin Invest. 2011;121:2065-73.
- Akhmetshina A, Palumbo K, Dees C, et al. Activation of canonical Wnt signaling is required for TGF-β-mediated fibrosis. Nat Commun. 2012;3:735.