Aim 1: To measure levels of microglia using the radiotracer [11C]PBR28 and PET brain imaging
in obese (n=50) vs. lean individuals (n=50). We will recruit 100 subjects who will
participate in a single [11C]PBR28 scan to measure levels of TSPO, a marker of microglia.
Aim 2: To determine differences in brain functional connectivity at rest and in response to a
decision- making task in obese (n=50) vs. lean individuals (n=50) using fMRI imaging. The
same subjects from Aim 1 will participate in a resting state functional magnetic resonance
imaging (fMRI) followed by a decision making task during fMRI acquisition.
Aim 3: To assess whether acute elevation of lipid levels through intralipid infusion in lean,
healthy individuals (n=20) will induce microglial activation. 20 lean individuals will be
recruited to participate in a paradigm that includes a baseline [11C]PBR28 scan, an infusion
of intralipid, and a second [11C]PBR28 scan approximately 4 hours post intralipid infusion.
We will attempt to utilize subjects from aim 1 in order to use their baseline scans for this
paradigm.
Aim 4: To determine whether there are differences in levels of microglia between individuals
with and without type 1 diabetes (n=20). 20 patients with diabetes (type 1 diabetes or type 2
diabetes)will be recruited to participate in a single [11C]PBR28 scan to compare to Aim 1
participants.