68Ga-FAPI PET/CT for diagnostic accuracy and therapeutic response assessment in bleomycin-induced pulmonary fibrosis: an integrated preclinical study

作者：Rui Sun, Yi‐Lin Huang, Hao Deng, Qixin Wang, Canran Xiao, Chunmei Guo, Tianyu Wang, Lisheng Liu, Jun Hua, Xiaoliang Chen · 发表于：Frontiers in Medicine · 年份：2025 · DOI：10.3389/fmed.2025.1613010 · 被引用次数：5 · 研究领域：Peptidase Inhibition and Analysis、Interstitial Lung Diseases and Idiopathic Pulmonary Fibrosis、Studies on Chitinases and Chitosanases

Objective This study aimed to assess the diagnostic and therapeutic monitoring potential of 68 Ga-fibroblast-activating protein inhibitor (FAPI) positron emission tomography/computed tomography (PET/CT) in bleomycin-induced pulmonary fibrosis (BIPF). Methods A preclinical model was established through intratracheal bleomycin administration (2 mg/kg) in C57BL/6 mice, with nintedanib treatment (50 mg/kg/day) initiated at day 28 post-modeling for longitudinal evaluation. Disease progression and therapeutic response were analyzed weekly over 5 weeks using 68 Ga-FAPI-04 PET/CT, complemented by histopathological validation through fibroblast activation protein (FAP) immunohistochemistry. Results In untreated fibrotic mice, 68 Ga-FAPI-04 uptake demonstrated a progressive increase, peaking at 4w (SUVmean: Left lung: 0.68 ± 0.14; Right lung: 0.65 ± 0.18). Conversely, nintedanib-treated mice exhibited an unexpected elevation in tracer uptake during late-phase imaging, but SUVR showed a decrease than untreated. Conclusion These findings underscore 68 Ga-FAPI-04 PET/CT as a sensitive tool for non-invasive assessment of BIPF early diagnosis and progression. The observed discordance in tracer uptake patterns between treatment groups highlights the need for further investigation into the temporal dynamics of antifibrotic therapy response.