FAPI Tracer en Vogue: Evaluating [68Ga]Ga-DATA5m.SA.FAPi for Molecular Imaging of Pulmonary Fibrosis

Title (eng)
FAPI Tracer en Vogue: Evaluating [68Ga]Ga-DATA5m.SA.FAPi for Molecular Imaging of Pulmonary Fibrosis
Author
Victoria Weissenböck
Author
Michaela Schlederer
Author
Latifa Bakiri
Author
Johanna Schaffenrath
Author
Erwin F. Wagner
Author
Frank Rösch
Author
Marcus Hacker
Author
Lukas Kenner
Author
Cécile Philippe
Abstract (eng)
Background/Objectives: Radiolabeled fibroblast activation protein inhibitors (FAPIs) are emerging as promising imaging agents assessing fibrotic diseases. This study evaluates [68Ga]Ga-DATA5m.SA.FAPi for imaging pulmonary fibrosis in two mouse models, bleomycin-induced (BLM) and a transgenic (fra-2tg) model, both displaying characteristics of human pulmonary fibrotic diseases. Methods: In the BLM model, C57BL/6 mice were treated with bleomycin or isotonic sodium chloride (controls) for 4, 5, and 6 weeks, followed by [68Ga]Ga-DATA5m.SA.FAPi PET/CT scans. Fra-2tg mice and wildtype (WT) littermates underwent at 7, 11, and 18/19 weeks of age a PET/CT scan. The selected timepoints correspond to early, middle, and late disease stages for each model. Imaging was complemented by ex vivo quantification, histological, and immunohistochemical (IHC) analyses. Results: In BLM mice, pulmonary [68Ga]Ga-DATA5m.SA.FAPi uptake showed a trend toward increase as early as 5 weeks of treatment compared with the controls, which was confirmed by ex vivo analysis (BLM: 3.31 ± 0.29%ID/g, n = 5; control: 1.61 ± 0.29%ID/g, n = 4; p = 0.0035). In fra-2tg mice, no significant differences could be detected. IHC revealed elevated pulmonary FAP expression specifically at early (BLM) and mild (fra-2tg) disease stages, whereas for BLM, tracer uptake was more pronounced at later stages. Conclusions: Our findings complement and extend observations from previous studies and support the potential of FAPI tracers as molecular imaging agents for pulmonary fibrosis.
Keywords (eng)
FAPFibrosisPETBleomycinFra-2
Type (eng)
journal article
Language
[eng]
Persistent identifier
https://phaidra.vetmeduni.ac.at/o:5361
DOI
10.3390/ph19010034
Is in series
Title (eng)
Pharmaceuticals
Volume
19
Issue
1
ISSN
1424-8247
Issued
2026
Number of pages
16
Publication
MDPI
Version type (eng)
version of record (published version)
Date issued
2026
Access rights (eng)
open access
License
CC BY 4.0 International
Rights statement (eng)
© 2025 by the authors