Idiopathic pulmonary fibrosis (IPF) is a progressive interstitial lung disease characterized by accumulation of extracellular matrix (ECM) and impaired gas exchange. The pathobiologic mechanisms which account for disease progression are poorly understood, but likely involve alterations in innate inflammatory cells, epithelial cells and fibroblasts. Thus, we seek to review the most recent literature highlighting the complex roles of neutrophils and macrophages as both promoters of fibrosis and defenders against infection. With respect to epithelial cells and fibroblasts, we review the data suggesting defective autophagy promotes the fibrogenic potential of both cell types and discuss new evidence related to matrix metalloproteinases, growth factors and cellular metabolism in the form of lactic acid generation that may have consequences for promoting fibrogenesis. We discuss potential crosstalk between innate and structural cell types and also highlight literature that may help explain the limitations of current IPF therapies.
- innate immunity
- epithelial cells
- Copyright © 2016, American Journal of Physiology-Lung Cellular and Molecular Physiology