Abstract 16931: Multiplexed Optical Imaging of Energy Metabolism in Brown Adipose Tissue in a Model of LV Hypertrophy
Introduction: Brown adipose tissue (BAT) plays an important role in obesity and insulin resistance. BAT is an energetically active organ and recent studies have suggested a reciprocal communication between BAT and the heart.
Hypothesis: We hypothesized that BAT would undergo energetic activation in mice with left ventricular hypertrophy (LVH) due to thoracic aortic banding (TAC), and that the resulting increase in energy metabolism substrate utilization could be visualized using a novel, multiplexed, optical imaging approach involving Cerenkov luminescence.
Methods: Fifteen weeks post-TAC, C57BL6 mice were simultaneously injected with F18-fluorodeoxyglucose (FDG) and bodipy-labelled C-16 free fatty acid (FFA). After 60 minutes, the heart and BAT were imaged optically, ex vivo, simultaneously, using Cerenkov luminescence for FDG and optical fluorescence for FFA.
Results: TAC resulted in a 28% (p<0.001) increase in heart weight as well as a 1.7x increase (p<0.01) in FDG uptake in the heart with no change in FFA uptake compared to controls. In BAT, TAC resulted in a 2.7x (p<0.001) increase in FDG uptake and a 1.8x (p<0.001) increase in FFA uptake vs. controls. Interestingly, BAT mass decreased by 39% (p<0.001) in TAC animals.
Conclusions: This novel optical approach allowed for the interrogation of several, energetic metabolic pathways in multiple tissues, simultaneously, and in a high throughput manner. Moreover, in this model of LVH, BAT is activated as evidenced by an increase in energy substrate utilization and a decrease in BAT mass, which may reflect a consumption of internal lipid stores. To our knowledge, this is the first description of the use of Cerenkov luminescence in the heart.
Figure Legend: A) Cerenkov luminescence showing increased FDG uptake in BAT from TAC animals vs. controls. B) Fluorescence imaging showing increased FFA uptake in BAT in TAC mice. (**p<0.001, AR-Average Radiance, ARE-Average Radiant Efficiency).
Author Disclosures: M. Panagia: Employment; Significant; Boston University Medical Center. Research Grant; Significant; National Institutes of Health, Boston University Medical Center. H. Chen: Research Grant; Significant; NIH. L. Josephson: Employment; Significant; Massachusetts General Hospital. W. Colucci: Employment; Significant; Boston Medical Center. D.E. Sosnovik: Employment; Significant; Massachusetts General Hospital. Research Grant; Significant; NIH.
- © 2016 by American Heart Association, Inc.