Idiopathic pulmonary fibrosis: Difference between revisions

It is hypothesized that the initial or repetitive injury in IPF occurs to the lung cells, called alveolar epithelial cells (AECs[[pneumocyte]]s), pneumocytes)the [[Type I cells|type I]] and [[type II cells]], which line the majority of the alveolar surface.<ref name=LoomisFlaherty>{{cite journal | vauthors = Loomis-King H, Flaherty KR, Moore BB | title = Pathogenesis, current treatments and future directions for idiopathic pulmonary fibrosis | journal = Current Opinion in Pharmacology | volume = 13 | issue = 3 | pages = 377–385 | date = June 2013 | pmid = 23602652 | pmc = 3686907 | doi = 10.1016/j.coph.2013.03.015 }}</ref> When type I AECscells are damaged or lost, it is thought that type II AECscells undergo proliferation to cover the exposed [[basement membrane]]s. In normal repair, the hyperplastic type II AECscells die and the remaining cells spread and undergo a differentiation process to become type I AECscells. Under pathologic conditions and in the presence of [[transforming growth factor beta]] (TGF-β), [[fibroblasts]] accumulate in these areas of damage and differentiate into [[myofibroblasts]] that secrete collagen and other proteins.<ref name=LoomisFlaherty /> In the current classification of the pathogenesis of IPF, it is believed that it occurs by way of the formation of a UIP (usual interstitial pneumonia) lesion, which then undergoes the aforementioned pathological condition characteristic of IPF.<ref>{{cite journal | vauthors = Raghu G, Remy-Jardin M, Myers JL, Richeldi L, Ryerson CJ, Lederer DJ, Behr J, Cottin V, Danoff SK, Morell F, Flaherty KR, Wells A, Martinez FJ, Azuma A, Bice TJ, Bouros D, Brown KK, Collard HR, Duggal A, Galvin L, Inoue Y, Jenkins RG, Johkoh T, Kazerooni EA, Kitaichi M, Knight SL, Mansour G, Nicholson AG, Pipavath SN, Buendía-Roldán I, Selman M, Travis WD, Walsh S, Wilson KC | display-authors = 6 | title = Diagnosis of Idiopathic Pulmonary Fibrosis. An Official ATS/ERS/JRS/ALAT Clinical Practice Guideline | journal = American Journal of Respiratory and Critical Care Medicine | volume = 198 | issue = 5 | pages = e44–e68 | date = September 2018 | pmid = 30168753 | doi = 10.1164/rccm.201807-1255ST | s2cid = 52130702 }}</ref> Other proposed repeated injury mechanisms indicate that IPF may result not just from a UIP lesion, but also from NSIP and DAD (nonspecific interstitial pneumonia and diffuse alveolar damage) lesions,<ref name=":0">{{cite journal | vauthors = Maher TM, Wells AU, Laurent GJ | title = Idiopathic pulmonary fibrosis: multiple causes and multiple mechanisms? | journal = The European Respiratory Journal | volume = 30 | issue = 5 | pages = 835–839 | date = November 2007 | pmid = 17978154 | doi = 10.1183/09031936.00069307 | s2cid = 17026757 | doi-access = free }}</ref> or a combination of several.