Usevalad Ustsinau

Stress impacts our health and triggers physiological adaptations, yet the metabolic programs engaged during stress remain incompletely understood. To fill this knowledge gap, we utilize total-body positron emission tomography (PET), multi-OMICS, and endocrine profiling to assess how various murine stress models affect systemic metabolic remodeling. We find that acute immobilization and surgery activate brown adipose tissue as part of the stress response, independently of hypothermia, thereby acting as a highly stress-sensitive metabolic hub. Additionally, we identify stress-specific hypo- and hypermetabolic signatures in different brain regions, and distinguish networks between brain and adipose tissue depots across the different stress groups. Our work presents a novel perspective on stress and its mobilization of metabolic resources and identifies PET imaging of brain and adipose tissue as a valuable, minimally invasive technique for tracking metabolic stress responses in mice, with relevance for animal welfare and disease models, and translational impact for mental health studies and preventive medicine.

14-(R,S)-[¹⁸F]fluoro-6-thia-heptadecanoic acid ([¹⁸F]FTHA) is a radiocompound for imaging the fatty acid circulation by positron emission tomography. A revived interest in imaging of lipid metabolism led us to a constant tracer production over three years, initially using a conventional vessel-based synthesizer and later transitioning to the cassette-based Elixys synthesizer. On the Elixys module, the radiochemical yield of [¹⁸F]FTHA could be increased by more than two times, reaching 13.01 ± 5.63% at the end of the synthesis, while maintaining necessary quality control results.