Abstract

Purpose Pneumoconiosis is characterized by pulmonary fibrosis. The activation of fibroblasts play an important role in the pathological development of pulmonary fibrosis. Chest CT, as a conventional examination to diagnose pulmonary fibrosis of pneumoconiosis, cannot evaluate the fibrosis activity. The application value of 18F-FAPI in pneumoconiosis is unclear. This study aimed to clarify the feasibility of 18F-FAPI PET/CT in non-invasively monitoring the activity evolution of pulmonary fibrosis in pneumoconiosis and the anti-fibrotic treatment.

Materials and Methods A preliminary clinical study was conducted on 6 pneumoconiosis patients and 4 healthy control individuals, correlation analysis was performed between the 18F-FAPI uptake in pulmonary fibrosis areas and the pulmonary diffusing function. Sprague-Dawley rat experiments were performed on three groups concluding pneumoconiosis model, pirfenidone-treated, and normal control groups. 18F-FAPI and 18F-FDG PET/CT, histopathologic, and hematological analysis were assessed monthly from modeling until 6 months.

Results 18F-FAPI uptake in fibrotic areas was found in the pneumoconiosis patients, and negatively correlated with the diffusing function (r = -0.929, P = 0.022). In the pneumoconiosis model, 18F-FAPI activity preceded one month earlier than relative collagen content (%) in Masson trichrome staining and the level of connective tissue growth factor in plasma, an indicator reflecting the fibroblast activation. The uptake of 18F-FAPI, rather than 18F-FDG, significantly decreased in the pirfenidone-treated group compared to the pneumoconiosis group (P < 0.05).

Conclusion 18F-FAPI PET/CT imaging holds promise for the early identification of pulmonary fibrosis activity and monitoring its evolution in pneumoconiosis, offering a precise clinical opportunity for targeted anti-fibrotic treatment.

Competing Interest Statement

The authors have declared no competing interest.

Funding Statement

This study was funded by the National Natural Science Foundation

Author Declarations

I confirm all relevant ethical guidelines have been followed, and any necessary IRB and/or ethics committee approvals have been obtained.

Yes

The details of the IRB/oversight body that provided approval or exemption for the research described are given below:

This study was approved by the Clinical Research Ethics Committee of the First Hospital of Shanxi Medical University

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Yes

Data Availability

All data produced in the present study are available upon reasonable request to the authors

AbbreviationsCTGFconnective tissue growth factorDLCOdiffusion lung carbon monoxideELISAenzyme-linked immunosorbent assayFAPfibroblast activation proteinFAPIfibroblast activation protein inhibitorsFVCforced vital capacityHRCThigh-resolution computerized tomographyIFimmunofluorescenceIHCimmunohistochemistryIL-6interleukin 6PETPositron Emission TomographySUVstandardized uptake valueTBRtarget-to-background ratioTNF-□tumor necrosis factor-alpha