Alzheimer & Dementia: Long-term increased pulse pressure may indicate a trend in brain microstructural changes in older adults

There is growing evidence that midlife is a critical window
to minimize the impact of vascular risk factors on cognitive decline.
Age-related arteriosclerosis, which begins around middle age, is thought to play a central role in brain aging, as increased pulse pressure in brain microvessels can disrupt cerebrovascular function, induce microbleeding and ischemia, which can lead to cumulative lesions
that impair cognition and brain function.

Prospective epidemiological studies report that midlife pulse pressure (PP) or pulse wave velocity (an alternative measure of arterial rigidity) can predict cognitive decline and dementia risk, however, the effects of arterial stiffness long before cognitive symptoms appear remain unclear
.
Therefore, scholars from the United States studied whether the long-term trajectory of PP predicts brain microstructure, the association of microstructure-mediated PP-executive function, and the association
of APOE genotype changing PP-microstructure.

Scholars at the University of San Diego studied the association between PP trajectories and brain microstructure measured by confined spectrum imaging in 146 community-dwelling older adults, whether microstructure mediated the association between PP trajectories and executive function, and whether the association with PP-restricted spectrum imaging was altered
by the APOE-ε4 state.

The results showed that participants with high PP trajectories had lower restrictive anisotropic diffusion (RI) compared to participants with low PP trajectories (i.
e.
, low pulse pressure), and the association of PP-executive function was mediated by subcortical and white matter RI
.
Among APOE-ε4 carriers, high PP was more strongly associated with lower RI and higher hindered diffusion than non-carriers
.

It can be seen that long-term elevation of PP indicates an abnormality in the microstructure, which may lead to impaired
executive function.
APOE-ε4 carriers may be the most vulnerable to adverse effects
of PP on brain microstructures.

References:

Pulse pressure trajectories predict brain microstructure in community-dwelling older adults: Associations with executive function and modification by APOE.
https://doi.
org/10.
1002/alz.
12844