Study links aortic stiffness with lower cerebral blood flow

August 31, 2018 by Liz Entman, Vanderbilt University
Credit: copyright American Heart Association

Greater aortic stiffness is related to lower cerebral blood flow, especially among individuals with increased genetic predisposition to Alzheimer's disease, according to research from Vanderbilt University Medical Center.

The study, published recently in Circulation, supports emerging evidence that , a hypertension-related factor, may play a role in cognitive decline, said Angela Jefferson, Ph.D., professor of Neurology and director of the Vanderbilt Memory and Alzheimer's Center.

The study, which was conducted in older adults, showed a pronounced effect in the cognitively normal participants who carried the APOE4 gene, a susceptibility risk factor for Alzheimer's disease. It coincides with evidence announced in July at the Alzheimer's Association International Conference in Chicago that suggested intensive lowering of blood pressure in aging adults reduces the risk of mild cognitive impairment and may have implications for the prevention of Alzheimer's disease and dementia.

"Given our study results and the recent SPRINT MIND findings, we have to strongly consider whether more aggressive medical management of vascular risk factors, and hypertension in particular, can result in better late-life cognitive outcomes for aging adults," Jefferson said. "Collectively, results suggest that the answer is yes."

She and colleagues at Vanderbilt used cardiac magnetic resonance imaging to assess across the aortic arch. The aorta, the largest artery in the body, is a compliant and flexible artery that naturally stiffens with age.

"The aorta constricts and dilates more than 40 million times per year," said Jefferson, the lead author of the study. "This amount of mechanical activity was perfectly fine back when life expectancy was 35 years of age, but life expectancy has more than doubled over the last couple of centuries.

"The aorta cannot withstand the excessive mechanical stress associated with so many additional years of constricting and dilating. As a result, the extracellular matrix within the vessel wall breaks down, and the aorta becomes increasingly stiff with age.

"It transitions from a flexible tube, like a garden hose, to something far stiffer, like a lead or concrete pipe," Jefferson said.

The study's findings add to a growing body of research detailing the strong connection between cardiovascular function and health as people age. A better understanding of this connection may lead to earlier detection and targeted interventions to prevent or mitigate consequences associated with aortic stiffening, including downstream cerebrovascular damage and further increases in blood pressure.

The research involved 270 participants in the Vanderbilt Memory and Aging Project, an ongoing interdisciplinary, longitudinal study being carried out at the Vanderbilt Memory and Alzheimer's Center. In addition to cardiac magnetic resonance imaging, participants also underwent brain .

"We examined blood flow in the brain using a sophisticated neuroimaging technique," Jefferson said. "Plus, we included a reactivity condition in which participants wear a mask that delivers just enough carbon dioxide to assess how responsive the cerebral vasculature is to subtle changes in arterial gas concentrations. If the vessels are healthy, they should dilate or expand to deliver more blood and oxygen to the brain."

Participants with the APOE4 gene had a more pronounced association between greater stiffness and lower cerebral blood flow, which was greatest in the temporal region of the brain.

"While there was an association between higher aortic stiffness, measured by pulse wave velocity, and reduced blood flow throughout the brain, what was particularly interesting is the interaction we discovered with the APOE4 gene," Jefferson said.

"Higher aortic stiffness related to lower in the temporal lobes, reflecting brain regions where Alzheimer's disease pathology first evolves. It is interesting that this Alzheimer's genetic risk factor modified the association in that way."

Explore further: Research links heart function to brain's memory center

Related Stories

Research links heart function to brain's memory center

November 8, 2017
Research by a team of Vanderbilt University Medical Center scientists suggests that older people whose hearts pump less blood have blood flow reductions in the temporal lobe regions of the brain, where Alzheimer's pathology ...

Physical fitness and healthy aorta key to brain ageing

June 12, 2018
The rate of decline in certain aspects of memory may be explained by a combination of overall physical fitness and the stiffness of the central arteries, researchers from Swinburne's Centre for Human Psychopharmacology have ...

Vascular brain injury is evident in people in their 40s

March 28, 2016
A large, multi-center study led by the UC Davis School of Medicine for the first time has shown that people as young as their 40s have stiffening of the arteries that is associated with subtle structural damage to the brain ...

Aortic stiffness, concentric LV remodeling linked in T2DM

April 25, 2018
(HealthDay)—For patients with type 2 diabetes, aortic stiffness is associated with concentric left ventricular (LV) remodeling, according to a study published online April 16 in Diabetes.

MRI-based measurement helps predict vascular disease in the brain

May 23, 2013
Aortic arch pulse wave velocity, a measure of arterial stiffness, is a strong independent predictor of disease of the vessels that supply blood to the brain, according to a new study published in the June issue the journal ...

Study shows poor heart function could be major risk for Alzheimer's disease

March 3, 2015
A healthier heart could prevent Alzheimer's disease, according to new research at Vanderbilt University Medical Center.

Recommended for you

Study clarifies ApoE4's role in dementia

September 20, 2018
ApoE4, a protein linked to both Alzheimer's disease and a form of dementia caused by damage of blood vessels in the brain, increases the risk of cognitive impairment by reducing the number and responsiveness of blood vessels ...

Machine learning IDs markers to help predict Alzheimer's

September 19, 2018
Nearly 50 million people worldwide have Alzheimer's disease or another form of dementia. These irreversible brain disorders slowly cause memory loss and destroy thinking skills, eventually to such an extent that self-care ...

Discovery could explain failed clinical trials for Alzheimer's, and provide a solution

September 19, 2018
Researchers at King's College London have discovered a vicious feedback loop underlying brain degeneration in Alzheimer's disease which may explain why so many drug trials have failed. The study also identifies a clinically ...

Air pollution may be linked to heightened dementia risk

September 18, 2018
Air pollution may be linked to a heightened risk of developing dementia, finds a London-based observational study, published in the online journal BMJ Open. The associations found couldn't be explained by factors known to ...

A new approach for finding Alzheimer's treatments

September 11, 2018
Considering what little progress has been made finding drugs to treat Alzheimer's disease, Maikel Rheinstädter decided to come at the problem from a totally different angle—perhaps the solution lay not with the peptide ...

Study prevents cognitive decline in older blacks with memory loss

September 10, 2018
With nearly twice the rate of dementia as whites, blacks are at a higher risk for developing diseases like Alzheimer's, but there has been little research on how to reduce this racial health disparity. A new study in black ...

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.