Metabolic positron emission tomography imaging and tumor growth inhibition during the Q neuron-induced hibernation-like state in mice

To the best of our knowledge, this is the first positron emission tomography (PET) study using a Q neuron–induced hypothermia and hypometabolism (QIH) mouse model, which is a synthetic hibernation-like state triggered by neural stimulation. We investigated changes in the in vivo dynamics of various essential nutrients and bioactive substances during hibernation using three types of metabolic probes: the glucose derivative [ 18 F]FDG (fluorodeoxyglucose), amino acid derivative L- m -[ 11 C]tolylalanine, and vitamin B 1 derivative [ 11 C]thiamine. We found that cardiac glucose metabolism was significantly reduced during the QIH state. Both vitamin B 1 and the amino acid derivatives exhibited rapid systemic distribution immediately after intravenous administration, which may indicate increased translocation into tissues based on altered circulatory dynamics or vascular wall properties. We also found that the proliferation of subcutaneously inoculated tumors was dramatically suppressed by QIH. Recently, hibernation has increasingly attracted attention because of its advantages, including reduced oxygen and energy consumption, that can mitigate organ damage. Notably, hibernation-like states may have potential applications in emergency and critical care medicine. Therefore, the advancement of hibernation research using QIH models and highlighted the potential of hibernation-like states for novel applications in cancer therapy and drug delivery.