Nabi HA, Sajjad M, Dhindsa S, Erb D, Wack D, Chaudhuri A, Dubey S, Wisniewski S, Dandona P.
Quantitative measurement of B amyloid plaques with C-11 PIB positron emission tomography of hypogonadal men with type 2 diabetes.
Human Amyloid Imaging 2011 Meeting Abstracts. 2011 Jan 15;
Introduction: Type 2 diabetes (DM) and hypogonadism in males are both known to increase the risk of Alzheimer's
disease (AD) markedly. We have recently shown that 33% of DM men have hypogonatrophic hypogonadism (HH)
with low free testosterone (FT) concentrations, elevated C-reactive protein and an increased fat mass. Since the
pathogenesis of AD is dependent upon oxidative and inflammatory stress, patients with HH and DM would be
expected to have enhanced risk of AD. Consistent with this, we have now discovered that DM men with low FT
have increased expression of amyloid precursor protein (APP) in their peripheral blood mononuclear cells, as
well as an increased expression of APP and tau protein in adipose tissue when compared to normal subjects.
Treatment of these patients with testosterone suppresses APP.
We hypothesize that hypogonadal DM men will show more expression of PIB in the brain than healthy men. The
relationship between the cellular and molecular indices and the uptake patterns of PIB on PET scans will also be
Methods: Dynamic C-11 PIB images of the brain were acquired from three subjects (2 with HH and DM, one
age-matched control, ages 42, 59, 59, respectively) following the iv administration of a mean of 8.3mCi (322mBq).
A noise reduction algorithm was applied and the intensity values of C-11 PIB (25 minutes post-injection) with
cerebellum reference were calculated for frontal, parietal, temporal, occipital, and insula regions.
Results: The two subjects with DM and HH showed more PIB retention than the normal subject, with prominent
differences in the temporal lobe (0.9563 vs 0.9009), and insula (0.9759 vs 0.9025). Occipital lobe values were
Conclusion: These preliminary results support our hypothesis that patients with type 2 DM and HH express more
amyloid in their brains as measured by C-11 PIB than a normal subject.