특발성 폐 섬유증과 방사성 폐렴의 차이 (IPF vs Radiation pneumonitis)

폐섬유증과 폐렴의 차이를 비교하면, 폐섬유증을 이해하는데 도움이 되는 것 같습니다. 폐에서 발생하지만 완전히 다른 두 질병의 차이를 통해 연구하시는데 조금이나마 도움이 되시길 바랍니다.

	특발성 폐 섬유증	방사성 폐렴
Triggering factors	Repetitive injury to the aging genetically susceptible alveolar epithelium	Direct and indirect injury of ionizing radiation to the AECs and vascular endothelial cells
Major role	fibroproliferative response (fibroproliferative repair phase becomes dominant under the influence of high levels of TGF-beta)	Inflammatory response
Early cellular effects of the triggering factors	Dysfunctional alveolar epithelial cells lead to a dysregulated repair course and type II cells cannot regenerate damaged cells. Apoptosis of alveolar epithelial cells, remarkable loss of type I cells and proliferation/ hyperplasia of type II cells are characteristic findings of IPF	radiation pneumonitis is mediated by DNA damage, oxidative stress (ROS), and dysregulation of various fibroinflammatory molecules. Radiation pneumonitis is associated with type 1 T-helper (Th1) immune response and alveolar M1 macrophages become activated with the increase of Th1 derived interferon gamma (IFN-γ)
Effects on vascular permeability	Increased vascular permeability Protein leakage into alveolar and interstitial spaces Formation of a provisional matrix, “wound clot"	Increased vascular permeability Interstitial and intraalveolar accumulation of inflammatory cells and proteins Interstitial and alveolar edema
Repair feature	Relatively strong fibroproliferative response, Relatively weak inflammatory response Aberrant repair mechanisms	Relatively strong inflammatory response, Relatively weak fibroproliferative response. Dysregulation of fibroinflammatory molecules and non-healing tissue response
Pivotal cellular mediator	Myofibroblasts	Alveolar macrophages
Response to the cell injury	Migration, proliferation and aberrant activation of epithelial cells GF/cytokine/chemokine release, mainly by AECs Formation of small fibroblast clusters, “fibroblastic foci” The EMT process, mainly through TGF-β1	GF/cytokine/chemokine release, mainly by activated alveolar macrophages Th1 immune response: alveolar M1 macrophage activation by Th-1 derived IFN-c Inflammation, increased inflammatory cell and protein accumulation in the interstitium Cell death
Reinforced fibrogenic milieu	Coagulation cascade activation Prevention of degradation of the provisional matrix by activated Factor X	Coagulation cascade activation
Abnormal lung remodeling	Excessive ECM secretion by myofibroblasts Basement membrane destruction through MMP2/MMP9 activation The additional effects of recruited fibrocytes through the CXCR4/CXCL12 axis Collagen deposition, fibrosis and scarring	Inflammatory cell infiltration Alveolar and interstitial edema Impaired lung functions and collapse