Insulin Resistance Is Associated With Enhanced Brain Glucose Uptake During Euglycemic Hyperinsulinemia: A Large-Scale PET Cohort
Research Design and Methods [18F]-fluorodeoxyglucose positron emission tomography (PET) data from 194 subjects scanned under clamp conditions were compiled from a single-center cohort. BGU was quantified by the fractional uptake rate. We examined the association of age, sex, M value from the clamp, steady-state insulin and free fatty acids levels, C-reactive protein, HbA1c, and presence of type 2 diabetes with BGU using Bayesian hierarchical modeling.
Results Insulin sensitivity, indexed by the M value, was associated negatively with BGU in all brain regions, confirming that in insulin resistant subjects BGU is enhanced during euglycemic hyperinsulinemia. In addition, the presence of type 2 diabetes was associated with a further increase in BGU. On the contrary, age was negatively related to BGU. Steady-state insulin levels, C-reactive protein, free fatty acids, sex, and HbA1c were not associated with BGU.
Conclusions In this large cohort of subjects of either sex across a wide range of age and insulin sensitivity, insulin sensitivity is the best predictor of brain glucose uptake.