Synthesis, 68Ga-radiolabeling, and preliminary in vivo assessment of a depsipeptide-derived compound as a potential PET/CT infection imaging agent
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Authors
Mokaleng, Botshelo B.
Ebenhan, Thomas
Ramesh, Suhas
Govender, Thavendran
Kruger, Hendrik G.
Parboosing, Raveen
Hazari, Puja P.
Mishra, Anil K.
Marjanovic-Painter, Biljana
Zeevaart, Jan Rijn
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Volume Title
Publisher
Hindawi Publishing
Abstract
Noninvasive imaging is a powerful tool for early diagnosis and monitoring of various disease processes, such as infections. An alarming shortage of infection-selective radiopharmaceuticals exists for overcoming the diagnostic limitations with unspecific tracers such as 67/68Ga-citrate or 18F-FDG. We report here TBIA101, an antimicrobial peptide derivative that was conjugated to DOTA and radiolabeled with 68Ga for a subsequent in vitro assessment and in vivo infection imaging using Escherichia coli-bearing mice by targeting bacterial lipopolysaccharides with PET/CT. Following DOTA-conjugation, the compound was verified for its cytotoxic and bacterial binding behaviour and compound stability, followed by 68Gallium-radiolabeling. µPET/CT using 68Ga-DOTA-TBIA101 was employed to detect muscular E. coli-infection in BALB/c mice, as warranted by the in vitro results. 68Ga-DOTA-TBIA101-PET detected E. coli-infected muscle tissue (SUV = 1.3–2.4) > noninfected thighs (P = 0.322) > forearm muscles (P = 0.092) > background (P = 0.021) in the same animal. Normalization of the infected thigh muscle to reference tissue showed a ratio of 3.0 ± 0.8 and a ratio of 2.3 ± 0.6 compared to the identical healthy tissue. The majority of the activity was cleared by renal excretion. The latter findings warrant further preclinical imaging studies of greater depth, as the DOTA-conjugation did not compromise the TBIA101's capacity as targeting vector.
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Keywords
Radiopharmaceuticals, Infectious diseases, Sterile inflammation, Depsidomycin-derived compounds, Radiolabeling
Sustainable Development Goals
Citation
Mokaleng, BB, Ebenhan, T, Ramesh, S, Govender, T, Kruger, HG, Parboosing, R, Hazari, PP, Mishra, AK, Marjanovic-Painter, B, Zeevaart, JR & Sathekge, MM 2015, 'Synthesis, 68Ga-radiolabeling, and preliminary in vivo assessment of a depsipeptide-derived compound as a potential PET/CT infection imaging agent', BioMed Research International, vol. 2015, art. #284354, pp. 1-12.