Idiopathic pulmonary fibrosis (IPF) is a fatal age-associated disease that is characterized by progressive and irreversible scarring of the lung. The pathogenesis of IPF is not completely understood and current therapies are limited to those that reduce the rate of functional decline in patients with mild-to-moderate disease. In this context, new therapeutic approaches that substantially improve the survival time and quality of life of these patients are urgently needed. Our incomplete understanding of the pathogenic mechanisms of IPF and the lack of appropriate experimental models that reproduce the key characteristics of the human disease are major challenges. As ageing is a major risk factor for IPF, age-related cell perturbations such as telomere attrition, senescence, epigenetic drift, stem cell exhaustion, loss of proteostasis and mitochondrial dysfunction are becoming targets of interest for IPF therapy. In this Review, we discuss current and emerging therapies for IPF, particularly those targeting age-related mechanisms, and discuss future therapeutic approaches.Fibrosis as a pathogenic mechanism occurs in numerous organs and diseases. Fibrosis results from abnormal tissue repair and is associated with persistent and/or severe tissue damage and cellular stress. Epithelial and/or endothelial injury caused by various insults triggers interrelated wound-healing pathways to restore homeostasis 1 . Failure to adequately contain or eliminate inciting factors can exacerbate inflammation and chronic woundCorrespondence to A.L.M. anamora@pitt.edu.
Competing interests statementThe authors declare competing interests: see Web version for details.
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Author Manuscript Author ManuscriptAuthor ManuscriptAuthor Manuscript healing responses, resulting in continued tissue damage and inadequate regeneration and, ultimately, fibrosis 2 . Although their aetiology and causative mechanisms differ, the various fibrotic diseases all have abnormal and exaggerated accumulation of extracellular matrix (ECM) components, mainly fibrillar collagens. The resulting fibrosis disturbs the normal architecture of affected organs, which ultimately leads to their dysfunction and failure. Nearly 45% of deaths in the developed world are attributable to some type of chronic fibroproliferative disease, including idiopathic pulmonary fibrosis (IPF) and end-stage fibrotic liver, kidney and heart disease 2 . The progressive nature of these diseases and the absence of effective treatments mean that a better understanding of the cellular and molecular mechanisms that contribute to the development of fibrosis is needed.Although IPF was originally thought to be an inflammation-driven disorder, clinical trials with a combination of anti-inflammatory drugs (prednisone, azathioprine and N-acetyl-Lcysteine (NAC)), failed to improve outcomes and instead increased mortality 3 . In 2014, two drugs, pirfenidone, a drug with poorly understood mechanisms, and nintedanib, a tyrosine kinase inhibitor, were approved for the treatment of IPF ...