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Review
. 2023 Mar 30;11(4):895.
doi: 10.3390/microorganisms11040895.

Idiopathic Pulmonary Fibrosis and Post-COVID-19 Lung Fibrosis: Links and Risks

Filippo Patrucco  1 , Paolo Solidoro  2   3 , Francesco Gavelli  4   5 , Daria Apostolo  4 , Mattia Bellan  4   6
Affiliations
Review

Idiopathic Pulmonary Fibrosis and Post-COVID-19 Lung Fibrosis: Links and Risks

Filippo Patrucco et al. Microorganisms. .

Abstract

Idiopathic pulmonary fibrosis (IPF) is considered the paradigmatic example of chronic progressive fibrosing disease; IPF does not result from a primary immunopathogenic mechanism, but immune cells play a complex role in orchestrating the fibrosing response. These cells are activated by pathogen-associated or danger-associated molecular patterns generating pro-fibrotic pathways or downregulating anti-fibrotic agents. Post-COVID pulmonary fibrosis (PCPF) is an emerging clinical entity, following SARS-CoV-2 infection; it shares many clinical, pathological, and immune features with IPF. Similarities between IPF and PCPF can be found in intra- and extracellular physiopathological pro-fibrotic processes, genetic signatures, as well as in the response to antifibrotic treatments. Moreover, SARS-CoV-2 infection can be a cause of acute exacerbation of IPF (AE-IPF), which can negatively impact on IPF patients' prognosis. In this narrative review, we explore the pathophysiological aspects of IPF, with particular attention given to the intracellular signaling involved in the generation of fibrosis in IPF and during the SARS-CoV-2 infection, and the similarities between IPF and PCPF. Finally, we focus on COVID-19 and IPF in clinical practice.

Keywords: COVID-19; SARS-CoV-2; idiopathic pulmonary fibrosis; post-COVID-19 pulmonary fibrosis; pulmonary fibrosis.

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Conflict of interest statement

The authors declare no conflict of interest. The funders had no role in the design of the study; in the collection, analyses, or interpretation of data; in the writing of the manuscript; or in the decision to publish the results.

Figures

Figure 1
Figure 1
COVID-19 and fibrotic damage. After SARS-CoV-2 infection, alveolar macrophages and alveolar epithelial cells type 2 secrete pro-inflammatory and pro-fibrotic cytokines, leading to fibroblast activation and differentiation in myofibroblasts, resulting in extracellular matrix deposition.
Figure 2
Figure 2
Pro-inflammatory and pro-fibrotic cascade after SARS-CoV-2 infection; AEC alveolar epithelial cells type I and II.
Figure 3
Figure 3
Post-COVID-19 follow-up schemes. In the presence of clinical and respiratory functional alterations, we suggest a follow-up high-resolution CT scan to investigate the presence of fibrotic alterations.
See this image and copyright information in PMC

References

    1. Raghu G., Remy-Jardin M., Richeldi L., Thomson C.C., Inoue Y., Johkoh T., Kreuter M., Lynch D.A., Maher T.M., Martinez F.J., et al. Idiopathic Pulmonary Fibrosis (an Update) and Progressive Pulmonary Fibrosis in Adults: An Official ATS/ERS/JRS/ALAT Clinical Practice Guideline. Am. J. Respir. Crit. Care Med. 2022;205:e18–e47. doi: 10.1164/rccm.202202-0399ST. - DOI - PMC - PubMed
    1. Martinez F.J., Collard H.R., Pardo A., Raghu G., Richeldi L., Selman M., Swigiris J.J., Taniguchi H., Wells A.U. Idiopathic pulmonary fibrosis. Nat. Rev. Dis. Prim. 2017;3:17074. doi: 10.1038/nrdp.2017.74. - DOI - PubMed
    1. Schwartz D.A. Idiopathic Pulmonary Fibrosis Is a Genetic Disease Involving Mucus and the Peripheral Airways. Ann. Am. Thorac. Soc. 2018;15((Suppl. S3)):S192–S197. doi: 10.1513/AnnalsATS.201802-144AW. - DOI - PMC - PubMed
    1. Taskar V.S., Coultas D.B. Is idiopathic pulmonary fibrosis an environmental disease? Proc. Am. Thorac. Soc. 2006;3:293–298. doi: 10.1513/pats.200512-131TK. - DOI - PubMed
    1. Hannum G., Guinney J., Zhao L., Zhang L., Hughes G., Sadda S., Klotzle B., Bibikova M., Fan J.-B., Gao Y., et al. Genome-wide Methylation Profiles Reveal Quantitative Views of Human Aging Rates. Mol. Cell. 2013;49:359–367. doi: 10.1016/j.molcel.2012.10.016. - DOI - PMC - PubMed