Session Type: Poster Session B
Session Time: 9:00AM-10:30AM
Background/Purpose: Metabolic imaging is routinely used to demonstrate aortitis in patients with giant-cell arteritis. We aimed to investigate aortitis in BALB/c IL1rn-/- mice, a preclinical model of aortitis, using 18F-FDG Positron Emission Tomography–Magnetic Resonance (PET-MR).
Methods: Fifteen first-generation specific and opportunistic pathogen-free (SOPF) 9-week-old IL1rn-/- mice and 15 wild-type BALB/cAnN mice were investigated using 18F-FDG PET-MR imaging, gamma-counting and immunostainings (anti-CD4, -CD8, -CD11c, -CD20, -CD31, -CD63, -CD163, -interferon-γ, interleukin-1α, -1β, -6, -17A antibodies). In addition, 5 second-generation specific pathogen-free (SPF) 9-week-old IL1rn-/- mice also underwent 18F-FDG PET-MR. Aortic 18F-FDG uptake was assessed as the target-to-background ratio (TBR) using time-of-flight MR angiography as vascular landmarks.
Results: 18F-FDG uptake measured by PET or gamma-counting was similar in the first-generation SOPF IL1rn-/- mice and the wild-type group. However, the first-generation IL1rn-/- mice exhibited significantly more interleukin-1β (p=0.021) and interleukin-6 (p=0.019) positive cells within abdominal aorta compared to the wild-type group. In addition, the second-generation SPF group exhibited a significantly higher TBR (p=0.0068) than the wild-type mice on the descending thoracic aorta, unlike the first-generation SOPF IL1rn-/- mice.
Conclusion: Besides the involvement of IL-1 and IL-6 in the mouse model of IL1rn-/- aortitis, this study validates 18F-FDG PET-MR as a useful tool for noninvasive monitoring of aortitis in this preclinical model. By demonstrating an increased aortic glucose metabolism, specifically in second-generation SPF 9-week-old IL1rn-/- mice, but not in the first-generation SOPF IL1rn-/- mice, compared to the wild-type group, our data suggest a pathophysiological role of the microbiota in this aortitis model and open perspectives for further pathophysiological and therapeutic investigations in this preclinical model.
To cite this abstract in AMA style:Deshayes S, Baugé C, Dupont P, Simard C, De Boysson H, Manrique A, Aouba A. 18F-FDG PET-MR Characterization of Aortitis in the IL1rn-/- Mouse Model of Giant-Cell Arteritis [abstract]. Arthritis Rheumatol. 2022; 74 (suppl 9). https://acrabstracts.org/abstract/18f-fdg-pet-mr-characterization-of-aortitis-in-the-il1rn-mouse-model-of-giant-cell-arteritis/. Accessed September 22, 2023.
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ACR Meeting Abstracts - https://acrabstracts.org/abstract/18f-fdg-pet-mr-characterization-of-aortitis-in-the-il1rn-mouse-model-of-giant-cell-arteritis/