Brain Amyloid Deposition Is Negatively Associated with Cardiac Amyloid Retention in Apo E4 Carriers: A Pilot Study

We investigated the relationship between amyloid deposition in the brain and heart using positron emission tomography (PET) scan with a focus on the influence of the apolipoprotein (Apo) E4 genotype.

Twenty-eight participants (12 healthy controls, 11 patients with mild cognitive impairment, and 5 patients with Alzheimer's disease) were recruited. Each subject visited the institution three times on separate days for echocardiography, brain and cardiac ¹⁸F-Florbetaben PET, and brain magnetic resonance imaging. Myocardial tracer retention (MTR, %) was calculated as the change in the myocardial mean standardized uptake value on summed-frame images of the first 5 min and between 15 and 20 min. Brain amyloid deposition was quantified using the Centiloid scale.

The mean MTR of all participants was 24.0%, with no significant difference between Apo E4 carriers and non-carriers. Within this pilot study, an inverse association was identified between MTR and brain amyloid deposition on the Centiloid scale specifically among Apo E4 carriers. In contrast, no significant association was found in Apo E4 non-carriers, consistent with the findings from the full-volume analysis.

In this pilot study, an inverse association was observed between brain amyloid β deposition and cardiac amyloid retention in Apo E4 carriers, but not in non-carriers. These findings represent an exploratory clinical observation regarding potential genotype-specific patterns in central and peripheral amyloid dynamics. While the results are hypothesis-generating, they highlight the need for further research into the brain-heart axis in amyloid-related diseases, particularly in genetically at-risk individuals using larger confirmatory cohorts.