In this study, individuals with and without post-traumatic stress disorder (PTSD) will
undergo one positron emission tomography (PET) scan using the radiotracer [11C]PBR28, which
binds to the 18kDa translocator protein (TSPO). A subset of individuals who complete the
first PET [11C]PBR28 scan will be invited to complete an inflammatory challenge and second
PET [11C]PBR28 scan. Approximately 3 hours prior to the second [11C]PBR28 PET scan,
lipopolysaccharide (LPS; endotoxin) will be administered to evoke a robust neuroimmune
response. Subjects will also undergo behavioral and cognitive testing. Vital signs,
subjective response, and peripheral biomarker levels will be assayed periodically throughout
the experimental session.
Specific aims: 1) Determine if individuals with PTSD exhibit neuroimmune system disruption
relative to well-matched comparators at baseline. 2) Determine if individuals with PTSD
exhibit a disrupted neuroimmune response after a classical immune stimulus relative to
well-matched comparators. 3) Determine if LPS differentially alters cognitive function,
subjective response, or physiological markers in individuals with PTSD compared to
well-matched comparators.
Hypothesis: Individuals with PTSD will exhibit a suppressed neuroimmune system at baseline
and an attenuated neuroimmune response following LPS challenge, relative to matched trauma
controls.