Preclinical evaluation of [18F]FDG-PET as a biomarker of lymphoid tissue disease and inflammation in Zika virus infection

• Published in: European journal of nuclear medicine and molecular imaging Vol. 49; no. 13; pp. 4516 - 4528
• Main Authors: Victorio, Carla Bianca Luena, Ong, Joanne, Tham, Jing Yang, Reolo, Marie Jennifer, Novera, Wisna, Msallam, Rasha, Watanabe, Satoru, Kalimuddin, Shirin, Low, Jenny G., Vasudevan, Subhash G., Chacko, Ann-Marie
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer Berlin Heidelberg 01.11.2022; Springer Nature B.V
• Subjects: Animal models; Animals; Autoradiography; Biomarkers; Biomarkers - metabolism; Cardiology; Cell proliferation; Computed tomography; Cytokines; Disease Models, Animal; Emission analysis; Fetuses; Flow cytometry; Fluorine isotopes; Fluorodeoxyglucose F18 - metabolism; Imaging; Immune system; In vivo methods and tests; Infection and inflammation; Infections; Inflammation - diagnostic imaging; Inflammation - metabolism; Inflammatory diseases; Inflammatory response; Lymphoid cells; Lymphoid tissue; Lymphoid Tissue - metabolism; Lymphoid Tissue - pathology; Medical imaging; Medicine; Medicine & Public Health; Mice; Myeloid cells; Nuclear Medicine; Oncology; Original; Original Article; Orthopedics; Pathogenesis; Pathology; Positron emission; Positron emission tomography; Positron Emission Tomography Computed Tomography - methods; Radiology; Real time; Spleen; Therapeutic applications; Tissue Distribution; Tomography, X-Ray Computed; Viral infections; Zika virus; Zika Virus - metabolism; Zika Virus Infection - diagnostic imaging; Zika Virus Infection - metabolism; Zika Virus Infection - pathology; AG129 mouse; Dengue; F]FDG; Viral inflammation; [; Viral infection; Zika; [18F]FDG
• ISSN: 1619-7070; 1619-7089
• DOI: 10.1007/s00259-022-05892-9

Purpose Zika (ZIKV) is a viral inflammatory disease affecting adults, children, and developing fetuses. It is endemic to tropical and sub-tropical countries, resulting in half the global population at risk of infection. Despite this, there are no approved therapies or vaccines against ZIKV disease. Non-invasive imaging biomarkers are potentially valuable tools for studying viral pathogenesis, prognosticating host response to disease, and evaluating in vivo efficacy of experimental therapeutic interventions. In this study, we evaluated [ 18 F]fluorodeoxyglucose ([ 18 F]FDG)-positron emission tomography (PET) as an imaging biomarker of ZIKV disease in a mouse model and correlated metabolic tracer tissue uptake with real-time biochemical, virological, and inflammatory features of tissue infection. Methods [ 18 F]FDG-PET/CT imaging was performed in an acute, lethal ZIKV mouse infection model, at increasing stages of disease severity. [ 18 F]FDG-PET findings were corroborated with ex vivo wholemount-tissue autoradiography and tracer biodistribution studies. Tracer uptake was also correlated with in situ tissue disease status, including viral burden and inflammatory response. Immune profiling of the spleen by flow cytometry was performed to identify the immune cell subsets driving tissue pathology and enhancing tracer uptake in ZIKV disease. Results Foci of increased [ 18 F]FDG uptake were consistently detected in lymphoid tissues—particularly the spleen—of ZIKV-infected animals. Splenic uptake increased with disease severity, and corroborated findings in tissue pathology. Increased splenic uptake also correlated with increased viral replication and elevated expression of pro-inflammatory cytokines within these tissues. ZIKV-infected spleens were characterized by increased infiltration of myeloid cells, as well as increased proliferation of both myeloid and lymphoid cells. The increased cell proliferation correlated with increased tracer uptake in the spleen. Our findings support the use of [ 18 F]FDG as an imaging biomarker to detect and track ZIKV disease in real time and highlight the dependency of affected tissue on the nature of the viral infection. Conclusion [ 18 F]FDG uptake in the spleen is a useful surrogate for interrogating in situ tissue viral burden and inflammation status in this ZIKV murine model.