ABSTRACT
Structural changes involving tissue remodelling and fibrosis are major features of many pulmonary diseases, including asthma, chronic obstructive pulmonary disease (COPD) and idiopathic pulmonary fibrosis (IPF). Abnormal deposition of extracellular matrix (ECM) proteins is a key factor in the development of tissue remodelling that results in symptoms and impaired lung function in these diseases. Tissue remodelling in the lungs is complex and differs between compartments. Some pathways are common but tissue remodelling around the airways and in the parenchyma have different morphologies. Hence it is critical to evaluate both common fibrotic pathways and those that are specific to different compartments; thereby expanding the understanding of the pathogenesis of fibrosis and remodelling in the airways and parenchyma in asthma, COPD and IPF with a view to developing therapeutic strategies for each. Here we review the current understanding of remodelling features and underlying mechanisms in these major respiratory diseases. The differences and similarities of remodelling are used to highlight potential common therapeutic targets and strategies. One central pathway in remodelling processes involves transforming growth factor (TGF)-ß induced fibroblast activation and myofibroblast differentiation that increases ECM production. The current treatments and clinical trials targeting remodelling are described, as well as potential future directions. These endeavours are indicative of the renewed effort and optimism for drug discovery targeting tissue remodelling and fibrosis.
Subject(s)
Lung Diseases/drug therapy , Lung Diseases/physiopathology , Airway Remodeling/physiology , Asthma/drug therapy , Asthma/physiopathology , Calcium-Binding Proteins/metabolism , Extracellular Matrix/metabolism , Fibroblasts , Fibrosis/physiopathology , Glycoproteins/metabolism , Humans , Idiopathic Pulmonary Fibrosis/drug therapy , Idiopathic Pulmonary Fibrosis/physiopathology , Matrix Metalloproteinases/metabolism , Pulmonary Disease, Chronic Obstructive/drug therapy , Pulmonary Disease, Chronic Obstructive/physiopathology , Transforming Growth Factor betaABSTRACT
Iidiopathic pulmonary fibrosis (IPF) diagnosis and treatment during this COVID-19 pandemic have been affected. COVID-19 has not only impacted the prognosis of these patients but also the approach to these patients. Pulmonary function tests (PFT) and lung biopsies are less encouraged now. Traditional antifibrotics used in IPF should be encouraged irrespective of patient lung function and in those with non-definite usual interstitial pneumonia in high resolution computed tomography.
Subject(s)
COVID-19/diagnosis , Idiopathic Pulmonary Fibrosis/diagnosis , Idiopathic Pulmonary Fibrosis/therapy , COVID-19/complications , Humans , Idiopathic Pulmonary Fibrosis/etiology , Idiopathic Pulmonary Fibrosis/physiopathology , Lung/pathology , Respiratory Function Tests , Respiratory Insufficiency/etiology , Severity of Illness IndexABSTRACT
PURPOSE OF REVIEW: Matrix metalloproteinases (MMPs) are a family of over 20 zinc-dependent proteases with different biological and pathological activities, and many have been implicated in several diseases. Although nonselective MMP inhibitors are known to induce serious side-effects, targeting individual MMPs may offer a safer therapeutic potential for several diseases. Hence, we provide a concise overview on MMP-12, given its association with pulmonary diseases, including asthma, chronic obstructive pulmonary disease (COPD), idiopathic pulmonary fibrosis, and other progressive pulmonary fibrosis (PPF), which may also occur in coronavirus disease 2019. RECENT FINDINGS: In asthma, COPD, and PPF, increased MMP-12 levels have been associated with inflammation and/or structural changes within the lungs and negatively correlated with functional parameters. Increased pulmonary MMP-12 levels and MMP-12 gene expression have been related to disease severity in asthma and COPD. Targeting MMP-12 showed potential in animal models of pulmonary diseases but human data are still very scarce. SUMMARY: Although there may be a potential role of MMP-12 in asthma, COPD and PPF, several pathophysiological aspects await elucidation. Targeting MMP-12 may provide further insights into MMP-12 related mechanisms and how this translates into clinical outcomes; this warrants further research.