Indices of Systemic Arterial Health are Associated With Cerebral Perfusion and Structure in a Population of Young and Old Adults

Abstract

Age‐related decrements in systemic arterial health may be indicative of alterations in cerebral perfusion and structure that are implicated in neurocognitive impairment. Purpose To determine if indicators of systemic arterial health are related to hemodynamic and structural changes in the brain in a population of healthy young and old adults. Hypothesis Poorer markers of arterial health will be associated with aging‐related hemodynamic and structural changes in the brain. Methods Young (n=13, f=7, m=6, 24±3 y, 71±18 kg) and old (n=14, f=5, m=9, 71±4 y, 83±15 kg) participants completed two experimental visits. In visit 1, systemic arterial health was assessed using carotid‐to‐femoral pulse wave velocity (PWV; indicator of central arterial stiffness; tonometry), left common carotid artery intima media thickness (IMT; indicator of carotid health; B‐mode Doppler Ultrasound), and brachial artery flow‐mediated dilation (FMD; indicator of peripheral endothelial function; duplex ultrasound). In visit 2, structural and arterial spin‐labelling neuroimaging data were acquired for computation of grey matter volume (GMV; indicator for structural integrity of the cortical tissues) and baseline cerebral blood flow (CBF0; indicator of gray matter vascular tone and perfusion). Between group differences were assessed using a two‐tailed, unpaired t‐test. Multiple linear regression analysis was used to model the relationship between indices of peripheral arterial function (PWV, IMT and FMD) and age with hemodynamic (CBF0) and structural (GMV) indices of brain health. Results PWV and IMT were greater in old vs. young adults (p<0.01). Reductions in FMD in the older adults approached significance (p=0.06). Both CBF0 and GMV were significantly lower in old vs. young adults (p<0.01). The dependent variable CBF 0 could be predicted from a linear combination (R2=0.72) of the independent variables age (p<0.01), PWV (p=0.04), FMD (p=0.04) and the contribution from IMT approached significance (p=0.07). The dependent variable GMV could be predicted by age alone (R2=0.74, p<0.01; all other variables p≥0.49). To isolate the relationship between indices of arterial health and brain structure, the regression analysis was repeated with age excluded. The dependent variable GMV could be predicted by IMT alone (R2=0.56, p<0.01) with the contribution from PWV approaching significance (p=0.10; FMD, p=0.83). Conclusion These data indicate that in a population of healthy young and old adults, decreased systemic arterial health is associated with hemodynamic and structural deficits in the brain. Support or Funding Information This work was supported by an Alzheimer’s Society of Brant, Haldimand Norfolk, Hamilton Halton award to REK MacPherson. TD Olver is supported by the Saskatchewan Health Research Foundation Establishment Grant #4522.