Preclinical Assessment of a (68)Ga-DOTA-Functionalized Depsipeptide as a Radiodiagnostic Infection Imaging Agent

The study assessed a radiolabeled depsipeptide conjugate ((68)Ga-DOTA-TBIA101) for its potential as an imaging agent targeting infection or infection-associated inflammation. (68)Ga-labeled DOTA-TBIA101 imaging was performed in (NZR1) healthy rabbits; (NZR2) rabbits bearing muscular sterile inflammation and Staphylococcus aureus (SA) infection; and (NZR3) rabbits infected with Mycobacterium tuberculosis (MTB) combined with a subcutaneous scruff infection of SA in the same animal. All animals were imaged using a PET/CT scanner at 5 and 60 min post injection. Images showed elevated accumulation of (68)Ga-DOTA-TBIA101 in the sterile muscular inflammation site (T/NT ratio = 2.6 ± 0.37 (5 min) and 2.8 ± 2.3 (60 min)) and muscles infected with MTB (T/NT ratio = 2.6 ± 0.35 (5 min) and 2.8 ± 0.16 (60 min)). The findings suggest that (68)Ga-DOTA-TBIA101-PET/CT may detect MTB-associated inflammation, although more foundational studies need to be performed to rationalize the diagnostic value of this technique.