Abstract 5105: Increased Glucose Uptake in Visceral versus Subcutaneous Adipose Tissue Revealed by PET Imaging
Background: The amount of visceral and subcutaneous adipose tissue (VAT and SAT, respectively) differentially predicts cardiovascular risk. Beyond volumetric measurement, glucose uptake in adipose tissue might yield additional information for risk stratification. This study explored differences in glucose utilization between VAT and SAT and potential mechanisms for this finding.
Methods and Results: Retrospective analysis of whole body FDG-PET scans from 59 patients showed that VAT exhibited higher FDG uptake than SAT (Figure A⇓, p<0.0001) independent of age, gender, body mass index, co-morbidities, or medications. To investigate the mechanisms underlying this observation, we then studied glucose uptake in stromal vascular cells (SVCs), a fraction of the adipose tissue which is rich in inflammatory cells. SVCs from VAT of diet-induced obese C57BL/6 mice exhibited higher glucose uptake than those from SAT (Figure B⇓, n=6, p=0.01). Evaluation of the expression of various genes involved in cellular glucose metabolism such as glucose transporters (GLUT 1, 3 and 4) and hexokinases (HK-1 and 2) showed increased expression of HK-1 in VAT-compared to SAT-derived SVCs (Figure C⇓, n=10, p=0.005). This finding illustrates one mechanism that may explain the above results.
Conclusions: This study showed non-invasively with FDG PET imaging that VAT has increased glucose uptake compared to SAT in human subjects, and showed experimentally that inflammatory cells may contribute to this difference. These findings add to our understanding of the nexus between adiposity, inflammation, and cardiovascular risk.