Relations of arterial stiffness and endothelial function to brain aging in the community

The immunogenicity of midbrain dopaminergic neurons and the implications for neural grafting trials in Parkinson's disease

Dopaminergic (DA) cell replacement therapies are a promising experimental treatment for Parkinson’s disease (PD) and a number of different types of DA cell-based therapies have already been trialled in patients. To date, the most successful have been allotransplants of foetal ventral midbrain but even then, the results have been inconsistent. This coupled to the ethical and logistical problems with using this tissue has meant that an alternative cell source has been sought of which human pluripotent stem cells (hPSCs) sources have proven very attractive. Robust protocols for making mesencephalic DA (mesDA) progenitor cells from hPSCs now exist and the first in-human clinical trials have or are about to start. However, while their safety and efficacy are well understood, relatively little is known about their immunogenicity and in this review, we briefly summarise this with reference mainly to the limited literature on human foetal DA cells.

Left amygdala volume and brain tissue pulsatility are associated with neuroticism: an MRI and ultrasound study

Brain changes associated with the personality trait of neuroticism have been partly elucidated. While subcortical brain volume changes, especially a larger amygdala, appear consistent in high neuroticism, functional changes, such as cerebral blood flow (CBF) differences, have shown conflicting results, possibly because of the limitations in methods of CBF measurement. In our study, we investigated changes in amygdala volume and CBF-related function associated with neuroticism in healthy and depressed subjects using both conventional magnetic resonance imaging (MRI) measures of brain volume and the innovative technique of ultrasound Tissue Pulsatility Imaging (TPI), which has a high level of detection in measuring brain tissue pulsatility (BTP). Middle-aged females with depression (n = 25) and without depression (n = 25) underwent clinical examination, magnetic resonance imaging (MRI) and ultrasound assessment (TPI). Neuroticism was positively associated with left amygdala volume and mean BTP in individuals without depression, in both simple and multiple regressions that included potential confounding factors such as age and body mass index. No association was found in the depressed group. We confirmed the role of the left amygdala in the brain physiology of neuroticism in nondepressed individuals. Moreover, we identified a novel mechanism associated with high neuroticism, namely BTP, that may reflect greater CBF and account for the increased risk of cerebrovascular disease in individuals with high neuroticism. Because neuroticism is considered a risk factor for depression, our paper provides potential objective biomarkers for the identification of subjects at risk for depression.

Impact of age and cyclooxygenase inhibition on the hemodynamic response to acute cognitive challenges

Structural and functional changes in the cerebral vasculature occur with advancing age, which may lead to impaired neurovascular coupling (NVC) and cognitive decline. Cyclooxygenase (COX) inhibition abolishes age-related differences in cerebrovascular reactivity, but it is unclear if COX inhibition impacts NVC. The purpose of this study was to examine the influence of aging on NVC before and after COX inhibition. Twenty-three young (age = 25 ± 4 yr) and 21 older (age = 64 ± 5 yr) adults completed two levels of difficulty of the Stroop and n-back tests before and after COX inhibition. Middle cerebral artery blood velocity (MCAv) was measured using transcranial Doppler ultrasound and mean arterial blood pressure (MAP) was measured using a finger cuff. Hemodynamic variables were measured at rest and in response to cognitive challenges. During the Stroop test, older adults demonstrated a greater increase in MCAv (young: 2.2 ± 6.8% vs. older: 5.9 ± 5.8%; P = 0.030) and MAP (young: 2.0 ± 4.9% vs. older: 4.8 ± 4.9%; P = 0.036) compared with young adults. There were no age-related differences during the n-back test. COX inhibition reduced MCAv by 30% in young and 26% in older adults (P < 0.001 for both). During COX inhibition, there were no age-related differences in the percent change in MCAv or MAP in response to the cognitive tests. Our results show that older adults require greater increases in MCAv and MAP during a test of executive function compared with young adults and that any age-related differences in NVC were abolished during COX inhibition. Collectively, this suggests that aging is associated with greater NVC necessary to accomplish a cognitive task.

Arterial elasticity, endothelial function and intracranial vascular health: A multimodal MRI study

Vascular dysfunctions, including arterial stiffness and endothelial dysfunction, are prevalent in hypertensive subjects. We aimed to study their relations to subclinical intracranial vascular health in this study. A total of 200 older hypertensive males without overt cardiovascular or cerebrovascular diseases were recruited. Arterial elasticity was measured as carotid-femoral pulse wave velocity (cfPWV) and endothelial function was measured as digital reactive hyperemia index (RHI). Cerebrovascular health was evaluated using MRI in four aspects: intracranial atherosclerosis, brain perfusion as cerebral blood flow (CBF), vascular rarefaction analyzed as visible arterial branches on angiography using a custom-developed analysis technique and small vessel disease measured as white matter hyperintensity (WMH). There was a significant negative association between cfPWV and CBF, suggesting a link between arterial stiffness and CBF decline. Higher cfPWV was also associated with presence of intracranial stenotic plaque and greater WMH volume. RHI was positively related to CBF, indicating that endothelial dysfunction was associated with reduced CBF. All the associations remained significant after adjustment for confounding variables. Arterial stiffness and endothelial dysfunction are associated with reduced brain perfusion in older hypertensive males. Arterial stiffness is also associated with global cerebral vascular injury, affecting both small and medium-to-large arteries.

Cortical thinning is associated with brain pulsatility in older adults: An MRI and NIRS study

Aging is accompanied by global brain atrophy occurring unequally across the brain. Cortical thinning is seen with aging with a larger loss in the frontal and temporal subregions. We explored the link between regional cortical thickness and regional cerebral pulsatility. Sixty healthy individuals were divided into two age groups, young (aged 19-31) and older (aged 65-75) adults. Each participant underwent a near-infrared spectroscopy (NIRS) scan to index regional brain pulsatility from cerebral pulse-transit-time-to-the peak-of-the-pulse (PTTp), an anatomical magnetic resonance imaging (MRI) and a phase-contrast MRI (PC-MRI) scan to measure arterial and cerebrospinal fluid (CSF) pulsatility. In older adults, the greatest association between cerebral pulsatility and cortical thickness was found in superior and middle temporal and superior, middle and inferior frontal areas, which are the regions perfused first by the internal carotid arteries. This association dropped in the postcentral and superior parietal regions. These findings suggest higher brain pulsatility as a potential risk factor contributing to cortical thinning for some brain regions more than others.

Endostatin as a Mediator Between Endothelial Function and Cognitive Performance in Those at Risk for Vascular Cognitive Impairment

Background:

Patients with coronary artery disease have an increased risk for developing vascular cognitive impairment. Endothelial function is often diminished and has been associated with lower cognitive performance in these patients. The link between endothelial function and cognition in coronary artery disease is not fully understood. Angiogenesis may play a role in mediating the association between endothelial function and cognition since angiogenic processes rely heavily on the endothelium.

Objective:

The aim of this study was to determine if markers of angiogenesis mediate the relationship between endothelial function and cognition in coronary artery disease patients.

Methods:

In 50 participants with coronary artery disease, endothelial function was assessed using peripheral arterial tonometry. Vascular endothelial growth factor (pro-angiogenic) and endostatin (anti-angiogenic) were measured in peripheral serum samples. Cognition was assessed using the Montreal Cognitive Assessment. A mediation analysis, using a bias corrected inferential bootstrapping method with 10,000 permutations, was used to determine if vascular endothelial growth factor or endostatin mediated an association between peripheral arterial tonometry measures and cognitive performance on the Montreal Cognitive Assessment.

Results:

Endostatin, but not vascular endothelial growth factor, mediated a relationship between endothelial function and cognitive performance when controlling for total years of education, body mass index, coronary artery bypass graft, stent, diabetes, and diuretic use. This analysis was also significant when delayed recall was substituted for the overall score on the Montreal Cognitive Assessment.

Conclusion:

These results suggest that endostatin mediates an association between endothelial function and cognitive performance in coronary artery disease.

3D amplified MRI (aMRI)

Purpose

Amplified MRI (aMRI) has been introduced as a new method of detecting and visualizing pulsatile brain motion in 2D. Here, we improve aMRI by introducing a novel 3D aMRI approach.

Methods

3D aMRI was developed and tested for its ability to amplify sub‐voxel motion in all three directions. In addition, 3D aMRI was qualitatively compared to 2D aMRI on multi‐slice and 3D (volumetric) balanced steady‐state free precession cine data and phase contrast (PC‐MRI) acquired on healthy volunteers at 3T. Optical flow maps and 4D animations were produced from volumetric 3D aMRI data.

Results

3D aMRI exhibits better image quality and fewer motion artifacts compared to 2D aMRI. The tissue motion was seen to match that of PC‐MRI, with the predominant brain tissue displacement occurring in the cranial‐caudal direction. Optical flow maps capture the brain tissue motion and display the physical change in shape of the ventricles by the relative movement of the surrounding tissues. The 4D animations show the complete brain tissue and cerebrospinal fluid (CSF) motion, helping to highlight the “piston‐like” motion of the ventricles.

Conclusions

Here, we introduce a novel 3D aMRI approach that enables one to visualize amplified cardiac‐ and CSF‐induced brain motion in striking detail. 3D aMRI captures brain motion with better image quality than 2D aMRI and supports a larger amplification factor. The optical flow maps and 4D animations of 3D aMRI may open up exciting applications for neurological diseases that affect the biomechanics of the brain and brain fluids.

Association of brain white matter lesions with arterial stiffness assessed by cardio-ankle vascular index. The Beijing Vascular Disease Evaluation STudy (BEST)

Background-The association of brain white matter lesions with arterial stiffness, as assessed by the cardio-ankle vascular index, is not well characterized in the population.

OBJECTIVE

The aim of this study was to quantify the cross-sectional association of brain white matter lesions with arterial stiffness assessed by the cardio-ankle vascular index among 1176 adults.

METHODS

We used logistic regression to evaluate the associations of the cardio-ankle vascular index with brain white matter lesions, detected by computed tomography or magnetic resonance imaging, versus normal brain white matter.

RESULTS

After adjustment for age, sex, systolic blood pressure, blood lipid level, C reactive protein level, homocysteine level, uric acid level, urea nitrogen level, creatinine level, hypertension, diabetes, coronary artery disease, peripheral artery disease, and stroke, the multivariable analysis showed that age, sex, systolic blood pressure, stroke and the cardio-ankle vascular index were independently associated with the presence of brain white matter lesions. Age range (odds ratio: from 2.48 to 33.64, all p < 0.05) showed the strongest association, followed by stroke (odds ratio: 7.16, 95% confidence interval: 4.59 to 11.16), male sex (odds ratio: 1.80, 95% confidence interval: 1.18 to 2.75), cardio-ankle vascular index (odds ratio: 1.26, 95% confidence interval: 1.06 to 1.50) and systolic blood pressure (odds ratio: 1.01, 95% confidence interval: 1.00 to 1.02).

CONCLUSION

Higher arterial stiffness assessed by the cardio-ankle vascular index was associated with the presence of brain white matter lesions. Longitudinal characterization of the observed associations is warranted to assess whether arterial stiffness predicts brain white matter lesions.

Impact of Cardiovascular Hemodynamics on Cognitive Aging

[Figure: see text].

Inflammation, Nitro-Oxidative Stress, Impaired Autophagy, and Insulin Resistance as a Mechanistic Convergence Between Arterial Stiffness and Alzheimer's Disease

The average age of the world's elderly population is steadily increasing. This unprecedented rise in the aged world population will increase the prevalence of age-related disorders such as cardiovascular disease (CVD) and neurodegeneration. In recent years, there has been an increased interest in the potential interplay between CVDs and neurodegenerative syndromes, as several vascular risk factors have been associated with Alzheimer's disease (AD). Along these lines, arterial stiffness is an independent risk factor for both CVD and AD. In this review, we discuss several inflammaging-related disease mechanisms including acute tissue-specific inflammation, nitro-oxidative stress, impaired autophagy, and insulin resistance which may contribute to the proposed synergism between arterial stiffness and AD.

Healthy aging and the blood-brain barrier

The blood-brain barrier (BBB) protects the central nervous system (CNS) from unregulated exposure to the blood and its contents. The BBB also controls the blood-to-brain and brain-to-blood permeation of many substances, resulting in nourishment of the CNS, its homeostatic regulation and communication between the CNS and peripheral tissues. The cells forming the BBB communicate with cells of the brain and in the periphery. This highly regulated interface changes with healthy aging. Here, we review those changes, starting with morphology and disruption. Transporter changes include those for amyloid beta peptide, glucose and drugs. Brain fluid dynamics, pericyte health and basement membrane and glycocalyx compositions are all altered with healthy aging. Carrying the ApoE4 allele leads to an acceleration of most of the BBB's age-related changes. We discuss how alterations in the BBB that occur with healthy aging reflect adaptation to the postreproductive phase of life and may affect vulnerability to age-associated diseases.

Cerebroarterial pulsatility and resistivity indices are associated with cognitive impairment and white matter hyperintensity in elderly subjects: A phase-contrast MRI study

Increased cerebroarterial pulsations are thought to be contributing factors in microvascular damage and cognitive impairment. In this study, we assessed the utility of two-dimensional (2D) phase-contrast MRI (PC-MRI) in quantifying cerebroarterial pulsations and evaluated the associations of pulsatile and non-pulsatile hemodynamic measures with cognitive performance and white matter hyperintensities (WMH). Neurocognitive assessments on 50 elderly subjects were performed using clinical dementia rating (CDR) and Montreal cognitive assessment (MoCA). An electrocardiogram-gated 2D PC-MRI sequence was used to calculate mean flow rate, pulsatility index (PI), and resistivity index (RI) of the internal carotid artery. For each subject, whole brain global cerebral blood flow (gCBF) and relative WMH volume were also quantified. Elevated RI was significantly associated with reduced cognitive performance quantified using MoCA (p = 0.04) and global CDR (p = 0.02). PI and RI were both significantly associated with relative WMH volume (p = 0.01, p < 0.01, respectively). However, non-pulsatile hemodynamic measures were not associated with cognitive impairment or relative WMH volume. This study showed that the cerebroarterial pulsatile measures obtained using PC-MRI have stronger association with the measures of cognitive impairment compared to global blood flow measurement and as such, might be useful as potential biomarkers of cerebrovascular dysfunction in preclinical populations.

Heart Disease and Stroke Statistics-2021 Update: A Report From the American Heart Association

BACKGROUND

The American Heart Association, in conjunction with the National Institutes of Health, annually reports the most up-to-date statistics related to heart disease, stroke, and cardiovascular risk factors, including core health behaviors (smoking, physical activity, diet, and weight) and health factors (cholesterol, blood pressure, and glucose control) that contribute to cardiovascular health. The Statistical Update presents the latest data on a range of major clinical heart and circulatory disease conditions (including stroke, congenital heart disease, rhythm disorders, subclinical atherosclerosis, coronary heart disease, heart failure, valvular disease, venous disease, and peripheral artery disease) and the associated outcomes (including quality of care, procedures, and economic costs).

METHODS

The American Heart Association, through its Statistics Committee, continuously monitors and evaluates sources of data on heart disease and stroke in the United States to provide the most current information available in the annual Statistical Update. The 2021 Statistical Update is the product of a full year's worth of effort by dedicated volunteer clinicians and scientists, committed government professionals, and American Heart Association staff members. This year's edition includes data on the monitoring and benefits of cardiovascular health in the population, an enhanced focus on social determinants of health, adverse pregnancy outcomes, vascular contributions to brain health, the global burden of cardiovascular disease, and further evidence-based approaches to changing behaviors related to cardiovascular disease.

RESULTS

Each of the 27 chapters in the Statistical Update focuses on a different topic related to heart disease and stroke statistics.

CONCLUSIONS

The Statistical Update represents a critical resource for the lay public, policy makers, media professionals, clinicians, health care administrators, researchers, health advocates, and others seeking the best available data on these factors and conditions.

Arterial Stiffness Is Associated with White Matter Disruption and Cognitive Impairment: A Community-Based Cohort Study

BACKGROUND

Mechanisms through which arterial stiffness impacts cognitive function are crucial for devising better strategies to prevent cognitive decline.

OBJECTIVE

To examine the associations of arterial stiffness with white matter integrity and cognition in community dwellings, and to investigate whether white matter injury was the intermediate of the associations between arterial stiffness and cognition.

METHODS

This study was a cross-sectional analysis on 952 subjects (aged 55.5±9.1 years) who underwent diffusion tensor imaging and measurement of brachial-ankle pulse wave velocity (baPWV). Both linear regression and tract-based spatial statistics were used to investigate the association between baPWV and white matter integrity. The association between baPWV and global cognitive function, measured as the mini-mental state examination (MMSE) was evaluated. Mediation analysis was performed to assess the influence of white matter integrity on the association of baPWV with MMSE.

RESULTS

Increased baPWV was significantly associated with lower mean global fractional anisotropy (β= -0.118, p < 0.001), higher mean diffusivity (β= 0.161, p < 0.001), axial diffusivity (β= 0.160, p < 0.001), and radial diffusivity (β= 0.147, p < 0.001) after adjustment of age, sex, and hypertension, which were measures having a direct effect on arterial stiffness and white matter integrity. After adjustment of age, sex, education, apolipoprotein E ɛ4, cardiovascular risk factors, and brain atrophy, we found an association of increased baPWV with worse performance on MMSE (β= -0.093, p = 0.011). White matter disruption partially mediated the effect of baPWV on MMSE.

CONCLUSION

Arterial stiffness is associated with white matter disruption and cognitive decline. Reduced white matter integrity partially explained the effect of arterial stiffness on cognition.

Arterial Stiffness in Aging: Does It Have a Place in Clinical Practice?: Recent Advances in Hypertension

Aortic stiffness increases markedly with age and is associated with excess risk for various adverse clinical outcomes, including heart disease, dementia, and kidney disease. Although evidence for adverse effects of aortic stiffening is overwhelming, integration of direct and indirect measures of aortic stiffness into routine clinical assessment has lagged behind the science. This brief review will examine recent evidence supporting the value of stiffness as an important new risk factor for hypertension and cardiovascular disease and will offer suggestions for incorporating stiffness measures into routine clinical practice.

Age and Sex Differences in the Associations of Pulse Pressure With White Matter and Subcortical Microstructure

Midlife vascular disease increases risk for dementia and effects of vascular dysfunction on brain health differ between men and women. Elevated pulse pressure, a surrogate for arterial stiffness, contributes to cerebrovascular pathology and white matter damage that may advance cognitive aging; however, it remains unclear how associations between pulse pressure and neural integrity differ by sex and age. This study used restriction spectrum imaging to examine associations between pulse pressure and brain microstructure in community-dwelling women (N=88) and men (N=55), aged 56 to 97 (mean, 76.3) years. Restricted isotropic (presumed intracellular), hindered isotropic (presumed extracellular), neurite density, and free water diffusion were computed in white matter tracts and subcortical regions. After adjustment for age and sex, higher pulse pressure correlated with lower restricted isotropic diffusion in global white matter, with more pronounced associations in parahippocampal cingulum, as well as in thalamus and hippocampus. Subgroup analyses demonstrated stronger correlations between pulse pressure and restricted isotropic diffusion in association fibers for participants ≤75 years than for older participants, with stronger effects for women than men of this age group. Microstructure in parahippocampal cingulum and thalamus differed by pulse pressure level regardless of antihypertensive treatment. Increased pulse pressure may lead to widespread injury to white matter and subcortical structures, with greatest vulnerability for women in late middle to early older age. Restriction spectrum imaging could be useful for monitoring microstructural changes indicative of neuronal loss or shrinkage, demyelination, or inflammation that accompany age-related cerebrovascular dysfunction.

Blood Pressure Variability and Dementia: A State-of-the-Art Review

Accumulating evidence demonstrates that blood pressure variability (BPV) may contribute to target organ damage, causing coronary heart disease, stroke, and renal disease independent of the level of blood pressure (BP). Several lines of evidence have also linked increased BPV to a higher risk of cognitive decline and incident dementia. The estimated number of dementia cases worldwide is nearly 50 million, and this number continues to grow with increasing life expectancy. Because there is no effective treatment to modify the course of dementia, targeting modifiable vascular factors continues as a top priority for dementia prevention. A clear understanding of the role of BPV in dementia may shed light on the etiology, early prevention, and novel therapeutic targets of dementia, and has therefore gained substantial attention from researchers and clinicians. This review summarizes state-of-art evidence on the relationship between BPV and dementia, with a specific focus on the epidemiological evidence, the underlying mechanisms, and potential intervention strategies. We also discuss challenges and opportunities for future research to facilitate optimal BP management and the clinical translation of BPV for the risk assessment and prevention of dementia.

[Cognitive impairment in heart failure: the role of microcirculation abnormalities]

Heart failure is one of the most frequent causes predisposing to cognitive impairment where its prevalence varies from 25 to 80% of cases. In this review, the mechanisms of microcirculatory abnormalities, which play a potential role in the development of cognitive impairment in patients with heart failure, are considered. Understanding of these mechanisms will help in the development of targeted therapy of cardiovascular and cerebrovascular diseases.

High pulse pressure is a risk factor for prodromal Alzheimer's disease: a longitudinal study

It has been increasingly evident that pulse pressure (PP) is associated with Alzheimer's disease (AD) but whether PP increases AD risk and the mechanism responsible for this association remains unclear. To investigate the effects of PP in the process of AD, we have evaluated the cross-sectional and longitudinal associations of PP with AD biomarkers, brain structure and cognition and have assessed the effect of PP on AD risk in a large sample (n= 1,375) from the Alzheimer's Disease Neuroimaging Initiative (ADNI). Multiple linear regression and mixed-model regression were employed in cross-sectional and longitudinal analyses respectively. Clinical disease progression was assessed using Cox proportional hazards models. High PP was associated with lower β-amyloid 42 (Aβ₄₂) (P= .015), and higher total tau (T-tau) (P= .011), phosphorylated tau (P-tau) (P= .003), T-tau/Aβ₄₂ (P= .004) and P-tau/Aβ₄₂ (P = .001), as well as heavier cortical amyloid-beta burden (P= .011). Longitudinally, baseline high PP was significantly associated with hippocampal atrophy (P= .039), entorhinal atrophy (P= .031) and worse memory performance (P= .058). Baseline high PP showed more rapid progression than those with normal PP (P <.001). These results suggest PP elevation could increase AD risk, which may be driven by amyloid plaques and subclinical neurodegeneration.

Hypertension Is Associated With an Earlier Age of Onset of Huntington's Disease

BACKGROUND AND OBJECTIVE

Hypertension (HTN) is associated with worsening clinical outcomes in neurodegenerative diseases. The relationship between HTN and the age of diagnosis (ADx) of Huntington's disease (HD) is not clear, however. This study sought to determine if the presence of HTN in adult patients with premanifest HD was associated with an earlier ADx compared with normotensive patients with HD.

METHODS

Premanifest participants from Enroll-HD were included if they had a cytosine-adenine-guanine greater than or equal to 36, baseline diagnostic confidence level less than 4, baseline total functional capacity score greater than 11, and baseline motor score less than 21. There were 3020 premanifest participants with HD, and 293 reported a diagnosis of HTN. HTN was transformed into a time-dependent variable, and a Cox proportional hazard survival model determine if the presence of HTN affected the time to motor conversion. Baseline cytosine-adenine-guanine-age product score, cytosine-adenine-guanine repeat length, baseline age, sex, baseline body mass index, smoking history, and region were included as covariates.

RESULTS

Participants with HTN had an increased annualized hazard of motor conversion compared to normotensive participants with HD (hazard ratio, 1.29; 95% confidence interval, 1.02-1.64; P = 0.034).

CONCLUSIONS

A previous study reported a protective effect of HTN in HD, but did not account for the fact that the prevalence of HTN increases with age. By controlling for this confounder, we more accurately outline the association between the ADx of HD to demonstrate that a diagnosis of HTN may be associated with an earlier ADx of HD. These results represent an association, however, and further investigation is warranted. © 2020 International Parkinson and Movement Disorder Society.

Aortic Hemodynamics and Cognitive Performance in Postmenopausal Women: Impact of Pregnancy History

BACKGROUND

Studies demonstrate an association between aortic hemodynamics and cognitive function. The impact of pregnancy history on this association is unknown.

METHODS

Postmenopausal women (age 59 ± 5 years; years since last pregnancy 35 ± 3) with either a history of preeclampsia (PE; n = 34) or a history of a normotensive pregnancy (NP; n = 30) underwent cognitive testing: Letter-Number Sequencing, Digit Span, Trail Making Test, and letter and category fluency. Applanation tonometry was used to derive aortic systolic and diastolic blood pressure and augmentation index.

RESULTS

Distribution of cognitive scores and aortic hemodynamic measures was similar between the PE and NP groups. Principal component (PC) analysis was used to reduce the 3 aortic hemodynamic measures and the 5 cognitive variables to single summary indices, each representing a weighted average of their respective constituent variables. Using a multivariable linear model based on these PCs that adjusted for pregnancy history and body mass index, the composite index of aortic hemodynamics was associated with the summary cognitive index, whether taking into account a potential interaction with pregnancy history (P = 0.035) or not (P = 0.026) (interaction P = 0.178). Multivariable modeling of individual cognitive tests revealed a differential association for letter fluency by pregnancy history (test for interaction P = 0.023); this score correlated with the aortic hemodynamic index in the PE (partial R² = 0.20), but not the NP (partial R² = 0.00) group.

CONCLUSIONS

Elevated aortic hemodynamics may negatively impact cognitive function in postmenopausal women with specific executive functions, such as letter fluency, being impacted more by a pregnancy history of PE.

Distinct association between cerebral arterial pulsatility and subtypes of cerebral small vessel disease

Background

Increased arterial resistance is a potential pathological mechanism of cerebral small vessel disease (cSVD).

Aim

In this study, we aimed to investigate the association between pulsatility index (PI) representing cerebral arterial resistance and subtypes of cSVD in patients with lacunar stroke.

Methods

We included consecutive lacunar stroke patients between 2010 and 2013. White matter hyperintensity (WMH) volume was rated using semi-automated quantitative methods. Additionally, the presence of old lacunar infarct (OLI), cerebral microbleed (CMB), or enlarged perivascular space (EPVS) was also evaluated. The relationship between PI, measured in each middle cerebral artery, and the subtype/burden of cSVD was analyzed in the relevant hemisphere.

Results

A total of 206 lacunar patients were included and 412 hemispheres were analyzed (mean age: 64 years, male: 68.4%). In multivariable analysis, PI was positively associated with the WMH volume [beta = 1.372, 95% confidence interval (CI) = 0.624 to 2.120, P < 0.001] after adjusting for confounders. PI was also related to the presence of OLI (adjusted odds ratio = 11.37, 95% CI = 2.55–48.56, P = 0.001); however, this relationship was not significant in CMB or EPVS. Regarding the cSVD burden, PI increased according to the WMH tertiles (P for trend < 0.001), the burden of OLI (P for trend < 0.001), and EPVS tertiles (P for trend < 0.001), showing a quantitative relationship.

Conclusions

Ipsilateral PI is closely associated with cSVD in patients with lacunar stroke. Furthermore, this association is different between subtypes of cSVD, which is suggestive of underlying pathophysiological differences.

Pulse Pressure: An Emerging Therapeutic Target for Dementia

Elevated pulse pressure can cause blood-brain barrier dysfunction and subsequent adverse neurological changes that may drive or contribute to the development of dementia with age. In short, elevated pulse pressure dysregulates cerebral endothelial cells and increases cellular production of oxidative and inflammatory molecules. The resulting cerebral microvascular damage, along with excessive pulsatile mechanical force, can induce breakdown of the blood-brain barrier, which in turn triggers brain cell impairment and death. We speculate that elevated pulse pressure may also reduce the efficacy of other therapeutic strategies for dementia. For instance, BACE1 inhibitors and anti-amyloid-β biologics reduce amyloid-β deposits in the brain that are thought to be a cause of Alzheimer’s disease, the most prevalent form of dementia. However, upregulation of oxidative and inflammatory molecules and increased amyloid-β secretion by cerebral endothelial cells exposed to elevated pulse pressure may hinder cognitive improvements with these drugs. Additionally, stem or progenitor cell therapy has the potential to repair blood-brain barrier damage, but chronic oxidative and inflammatory stress due to elevated pulse pressure can inhibit stem and progenitor cell regeneration. Finally, we discuss current efforts to repurpose blood pressure medications to prevent or treat dementia. We propose that new drugs or devices should be developed to safely reduce elevated pulse pressure specifically to the brain. Such novel technologies may alleviate an entire downstream pathway of cellular dysfunction, oxidation, inflammation, and amyloidogenesis, thereby preventing pulse-pressure-induced cognitive decline. Furthermore, these technologies may also enhance efficacy of other dementia therapeutics when used in combination.

Arterial Stiffness is Associated with Intracranial Arterial Stenosis other than Dolichoectasia in the General Population

Aims: The relationship between central arterial stiffness and aging-related intracranial arteriopathy is not well investigated in the general population. In a population-based study, we investigated arterial stiffness in relation to intracranial atherosclerotic stenosis and intracranial arterial dolichoectasia.

Methods: This study was a cross-sectional analysis on 1,123 subjects (aged 56.0 ± 9.3 years, 37.9% men) of the population-based Shunyi study in China. Arterial stiffness was assessed by measuring brachial-ankle pulse wave velocity (baPWV). Intracranial atherosclerotic stenosis and intracranial arterial dolichoectasia were evaluated via brain magnetic resonance angiography. Multivariate regression models were constructed to investigate the association between baPWV and intracranial large artery diseases.

Results: Increased baPWV was significantly associated with higher prevalence of intracranial atherosclerotic stenosis (odds ratio for the highest quartile of baPWV compared with the lowest quartile, 3.66 [95% confidence interval, 1.57–8.54]), after adjustment for cardiovascular risk factors in multivariate analysis. BaPWV was not associated with the presence of basilar artery dolichoectasia and dilation of basilar artery and internal carotid artery. When the diameters of intracranial arteries were regarded as continuous variables, increased baPWV was inversely related to the internal carotid artery diameter in fully adjusted models (β ± SE, −0.083 ± 0.042, p = 0.047).

Conclusions: This population-based study demonstrates that arterial stiffness was more likely associated with intracranial stenotic arteriopathy other than intracranial dilative arteriopathy.

Correlation of Cerebral White Matter Lesions with Carotid Intraplaque Neovascularization assessed by Contrast-enhanced Ultrasound

PURPOSE

Carotid atherosclerotic plaque is closely associated with cerebral white matter lesions (WMLs), while intraplaque neovascularization (IPN) contributes significantly to arterial remodeling and plaque vulnerability. In this study, we aim to evaluate the correlation of carotid IPN with cerebral WMLs.

METHODS

The presence of IPN and WMLs were assessed by contrast-enhanced ultrasound (CEUS) and MRI respectively. IPN was evaluated utilizing semi-quantification visual grading scale and WMLs was divided according to Fazekas grading scale. We investigated the baseline data, Fazekas grades, and IPN grades among 269 participants. We explored the influences of each variable on Fazekas grades using ordinal logistic regression and evaluated the relationship between IPN grades and WMLs Fazekas grades.

RESULTS

Increased age (OR: 1.06, P<0.001), hypertension (OR: 2.17, P=0.002), cerebral infarction (OR: 1.74, P=0.046), and elevated carotid IPN grading were significantly associated with aggravated Fazekas grades (grade 2 or 3). To be specific, people having grade 3, 2, and 1 carotid IPN were 25.84 (P<0.001), 10.64 (P<0.001), and 5.96 (P=0.010) times as likely to have elevated Fazekas grades compared with those who having grade 0 carotid IPN.

CONCLUSION

Increased carotid IPN is independently correlated with aggravated cerebral WMLs.

Carotid Artery Stiffness is Associated With Cognitive Performance in Former Smokers With and Without Chronic Obstructive Pulmonary Disease

Background Heavy smokers perform worse on neuropsychological assessment than age-matched peers. However, traditional pulmonary measures of airflow limitation and hypoxemia explain only a modest amount of variance in cognition. The current objective was to determine whether carotid artery stiffness is associated with cognition in former smokers beyond the effects of amount of smoking and pulmonary function. Methods and Results Eighty-four former smokers including individuals across a spectrum of airflow limitation severity were included: 30 without chronic obstructive pulmonary disease (Global Initiative for Chronic Obstructive Lung Disease [GOLD] 0 with normal spirometry and lung computed tomography), 31 with mild-moderate chronic obstructive pulmonary disease (GOLD 1-2), and 23 with severe-very severe chronic obstructive pulmonary disease (GOLD 3-4). Participants completed questionnaires, spirometry, carotid ultrasonography, and neuropsychological testing. Multiple linear regression was used to determine whether carotid artery stiffness is associated with neuropsychological performance in 4 cognitive domains after adjusting for age, sex, pack-years of smoking, estimated premorbid intellectual functioning, and airflow limitation. Higher carotid artery β-stiffness index was associated with reduced executive functioning-processing speed in the fully adjusted model (β=-0.49, SE=0.14; P=0.001). Lower premorbid intellectual function, male sex, and presence of airflow limitation (GOLD 1 or 2 and GOLD 3 or 4) were also associated with worse executive functioning-processing speed. β-Stiffness index was not significantly associated with performance in other cognitive domains. Conclusions Carotid artery stiffness is associated with worse performance on executive functioning-processing speed in former smokers beyond the effects of aging, amount of past smoking, severity of airflow limitation, and hypoxemia. Future research should examine whether carotid stiffness can be used to identify former smokers at risk for subsequent cognitive impairment.

Does vascular stiffness predict white matter hyperintensity burden in ischemic heart disease with preserved ejection fraction?

The survival rate of patients with ischemic heart disease (IHD) is increasing. However, survivors experience increased risk for neurological complications. The mechanisms for this increased risk are unknown. We tested the hypothesis that patients with IHD have greater carotid and cerebrovascular stiffness, and these indexes predict white matter small vessel disease. Fifty participants (age, 40-78 yr), 30 with IHD with preserved ejection fraction and 20 healthy age-matched controls, were studied using ultrasound imaging of the common carotid artery (CCA) and middle cerebral artery (MCA), as well as magnetic resonance imaging (T1, T2-FLAIR), to measure white matter lesion volume (WMLv). Carotid β-stiffness provided the primary measure of peripheral vascular stiffness. Carotid-cerebral pulse wave transit time (ccPWTT) provided a marker of cerebrovascular stiffness. Pulsatility index (PI) and resistive index (RI) of the MCA were calculated as measures of downstream cerebrovascular resistance. When compared with controls, patients with IHD exhibited greater β-stiffness [8.5 ± 3.3 vs. 6.8 ± 2.2 arbitrary units (AU); P = 0.04], MCA PI (1.1 ± 0.20 vs. 0.98 ± 0.18 AU; P = 0.02), and MCA RI (0.66 ± 0.06 vs. 0.62 ± 0.07 AU; P = 0.04). There was no difference in WMLv between IHD and control groups (0.95 ± 1.2 vs. 0.86 ± 1.4 mL; P = 0.81). In pooled patient data, WMLv correlated with both β-stiffness (R = 0.34, P = 0.02) and cerebrovascular ccPWTT (R = -0.43, P = 0.02); however, β-stiffness and ccPWTT were not associated (P = 0.13). In multivariate analysis, WMLv remained independently associated with ccPWTT (P = 0.02) and carotid β-stiffness (P = 0.04). Patients with IHD expressed greater β-stiffness and cerebral microvascular resistance. However, IHD did not increase risk of WMLv or cerebrovascular stiffness. Nonetheless, pooled data indicate that both carotid and cerebrovascular stiffness are independently associated with WMLv.NEW & NOTEWORTHY This study found that patients with ischemic heart disease (IHD) with preserved ejection fraction and normal blood pressures exhibit greater carotid β-stiffness, as well as middle cerebral artery pulsatility and resistive indexes, than controls. White matter lesion volume (WMLv) was not different between vascular pathology groups. Cerebrovascular pulse wave transit time (ccPWTT) and carotid β-stiffness independently associate with WMLv in pooled participant data, suggesting that regardless of heart disease history, ccPWTT and β-stiffness are associated with structural white matter damage.

Arterial Stiffness and Cognition Among Adults: A Systematic Review and Meta-Analysis of Observational and Longitudinal Studies

Background

To estimate the strength of the cross‐sectional and longitudinal association between arterial stiffness, measured by pulse‐wave velocity, and cognitive function, distinguishing between global cognition, executive functions, and memory and to examine the influence of demographic, clinical, and assessment characteristics on this relationship.

Methods and Results

Systematic review of MEDLINE (via PubMed), Scopus, and WOS databases from their inception to March 2019, to identify cross‐sectional and longitudinal studies on the association between pulse‐wave velocity and cognitive domains (ie, global cognition, executive functions, and memory) among adult population. A total of 29 cross‐sectional and 9 longitudinal studies support the negative relationship between arterial stiffness and cognitive function, including global cognition, executive function, and memory. Demographic, clinical, and assessment characteristics did not substantially modify the strength of this association.

Conclusions

Evidence reveals a negative association between arterial stiffness, measured using pulse‐wave velocity, and cognition, specifically executive function, memory, and global cognition. This association seems to be independent of demographic, clinical, and assessment characteristics. These results accumulate evidence supporting that pulse‐wave velocity assessment could be a useful tool to identify individuals at high risk of cognitive decline or early stages of cognitive decline, to implement interventions aimed at slowing the progression to dementia.

The association between resting-state functional magnetic resonance imaging and aortic pulse-wave velocity in healthy adults

Resting‐state functional magnetic resonance imaging (rs‐fMRI) is frequently used to study brain function; but, it is unclear whether BOLD‐signal fluctuation amplitude and functional connectivity are associated with vascular factors, and how vascular‐health factors are reflected in rs‐fMRI metrics in the healthy population. As arterial stiffening is a known age‐related cardiovascular risk factor, we investigated the associations between aortic stiffening (as measured using pulse‐wave velocity [PWV]) and rs‐fMRI metrics. We used cardiac MRI to measure aortic PWV (an established indicator of whole‐body vascular stiffness), as well as dual‐echo pseudo‐continuous arterial‐spin labeling to measure BOLD and CBF dynamics simultaneously in a group of generally healthy adults. We found that: (1) higher aortic PWV is associated with lower variance in the resting‐state BOLD signal; (2) higher PWV is also associated with lower BOLD‐based resting‐state functional connectivity; (3) regions showing lower connectivity do not fully overlap with those showing lower BOLD variance with higher PWV; (4) CBF signal variance is a significant mediator of the above findings, only when averaged across regions‐of‐interest. Furthermore, we found no significant association between BOLD signal variance and systolic blood pressure, which is also a known predictor of vascular stiffness. Age‐related vascular stiffness, as measured by PWV, provides a unique scenario to demonstrate the extent of vascular bias in rs‐fMRI signal fluctuations and functional connectivity. These findings suggest that a substantial portion of age‐related rs‐fMRI differences may be driven by vascular effects rather than directly by brain function.

Central arterial stiffness and retinal vessel calibers: the Atherosclerosis Risk in Communities Study-Neurocognitive Study

BACKGROUND

The retinal microvasculature provides a window to the cerebral vasculature and enables examination of changes in retinal caliber that may mimic those occurring in cerebrovascular disease. The association of central arterial stiffness and retinal vessel caliber in a population sample is not fully understood.

METHODS

In 1706 older adults (mean age 76.3, 58.1% women) from the population-based Atherosclerosis Risk in Communities Study, we examined the cross-sectional association of central arterial stiffness [carotid-femoral pulse wave velocity (cfPWV)] with retinal vessel calibers [central retinal arteriolar equivalent (CRAE) and central retinal vein equivalent (CRVE)]. We estimated the association of cfPWV with CRAE narrowing (<25th percentile) and CRVE widening (>75th percentile) after adjustment for age, sex, race-field center, BMI, smoking, and type 2 diabetes. We tested for effect modification by sex, hypertension, and type 2 diabetes.

RESULTS

Carotid-femoral PWV (m/s) was not associated with the odds of CRAE narrowing [odds ratio (OR): 0.99; 95% CI: 0.95-1.03]. The association of cfPWV with CRVE widening was stronger in those without hypertension (OR: 1.10; 95% CI: 1.01-1.20) versus those with hypertension (OR: 1.01 95% CI: 0.96-1.05) and slightly stronger in those with type 2 diabetes (OR: 1.07; 95% CI: 1.00-1.14) versus without type 2 diabetes (OR: 1.01; 95% CI: 0.96-1.06).

CONCLUSIONS

In older adults, cfPWV was associated with wider retinal venular caliber, particularly in individuals without hypertension. Central arterial stiffening may be associated with cerebral microvascular changes, as exhibited in its retinal vasculature component.

Heart Disease and Stroke Statistics-2020 Update: A Report From the American Heart Association

BACKGROUND

The American Heart Association, in conjunction with the National Institutes of Health, annually reports on the most up-to-date statistics related to heart disease, stroke, and cardiovascular risk factors, including core health behaviors (smoking, physical activity, diet, and weight) and health factors (cholesterol, blood pressure, and glucose control) that contribute to cardiovascular health. The Statistical Update presents the latest data on a range of major clinical heart and circulatory disease conditions (including stroke, congenital heart disease, rhythm disorders, subclinical atherosclerosis, coronary heart disease, heart failure, valvular disease, venous disease, and peripheral artery disease) and the associated outcomes (including quality of care, procedures, and economic costs).

METHODS

The American Heart Association, through its Statistics Committee, continuously monitors and evaluates sources of data on heart disease and stroke in the United States to provide the most current information available in the annual Statistical Update. The 2020 Statistical Update is the product of a full year's worth of effort by dedicated volunteer clinicians and scientists, committed government professionals, and American Heart Association staff members. This year's edition includes data on the monitoring and benefits of cardiovascular health in the population, metrics to assess and monitor healthy diets, an enhanced focus on social determinants of health, a focus on the global burden of cardiovascular disease, and further evidence-based approaches to changing behaviors, implementation strategies, and implications of the American Heart Association's 2020 Impact Goals.

RESULTS

Each of the 26 chapters in the Statistical Update focuses on a different topic related to heart disease and stroke statistics.

CONCLUSIONS

The Statistical Update represents a critical resource for the lay public, policy makers, media professionals, clinicians, healthcare administrators, researchers, health advocates, and others seeking the best available data on these factors and conditions.

When classical music relaxes the brain: An experimental study using Ultrasound Brain Tissue Pulsatility Imaging

INTRODUCTION

Recent evidence suggests that biomechanical parameters of the brain, such as Brain Tissue Pulsatility (BTP), could be involved in emotional reactivity. However, no study has investigated the impact of an emotional task on BTP. We used the ultrasound method of Tissue Pulsatility Imaging (TPI) to assess changes in BTP to exciting and relaxing classical music, in a musical perception task, as a validated paradigm to assess emotional reactivity.

METHODS

25 healthy volunteers were exposed via earphones to four 5-minute musical excerpts (two exciting and two relaxing musical excerpts) presented in a randomized order and intersected by 5 silence periods. Measures of BTP, Heart Rate (HR) and Skin Conductance (SC) were collected during the entire task.

RESULTS

The BTP significantly decreased with relaxing music compared to silence, and especially with the excerpt 'Entrance of the Shades' by Minkus. The HR and SC, but not Heart Rate Variability, were also decreased with relaxing music. We found no significant effect of exciting music.

DISCUSSION

We report, for the first time, that classical relaxing music decreases the amplitude of the brain pulsatile movements related to cerebral blood flow and mechanical properties of the brain parenchyma, which provides further evidence of the involvement of BTP in emotional reactivity. In addition, we validate the use of TPI as a non-invasive, portable and low cost tool for studies in psychophysiology, with the potential to be implemented as a biomarker in musicotherapy trials notably.

Cardiac and respiration-induced brain deformations in humans quantified with high-field MRI

Microvascular blood volume pulsations due to the cardiac and respiratory cycles induce brain tissue deformation and, as such, are considered to drive the brain's waste clearance system. We have developed a high-field magnetic resonance imaging (MRI) technique to quantify both cardiac and respiration-induced tissue deformations, which could not be assessed noninvasively before. The technique acquires motion encoded snapshot images in which various forms of motion and confounders are entangled. First, we optimized the motion sensitivity for application in the human brain. Next, we isolated the heartbeat and respiration-related deformations, by introducing a linear model that fits the snapshot series to the recorded physiological information. As a result, we obtained maps of the physiological tissue deformation with 3mm isotropic spatial resolution. Heartbeat and respiration-induced volumetric strain were significantly different from zero in the basal ganglia (median (25-75% interquartile range): 0.85·10^-3 (0.39·10^-3-1.05·10^-3), p ​= ​0.0008 and -0.28·10^-3 (-0.41·10^-3-0.06·10^-3), p ​= ​0.047, respectively. Smaller volumetric strains were observed in the white matter of the centrum semi ovale (0.28·10^-3 (0-0.59·10^-3) and -0.06·10^-3 (-0.17·10^-3-0.20·10^-3)), which was only significant for the heartbeat (p ​= ​0.02 and p ​= ​0.7, respectively). Furthermore, heartbeat-induced volumetric strain was about three times larger than respiration-induced volumetric strain. This technique opens a window on the driving forces of the human brain clearance system.

Dissociation of Cerebral Blood Flow and Femoral Artery Blood Pressure Pulsatility After Cardiac Arrest and Resuscitation in a Rodent Model: Implications for Neurological Recovery

Background

Impaired neurological function affects 85% to 90% of cardiac arrest (CA) survivors. Pulsatile blood flow may play an important role in neurological recovery after CA. Cerebral blood flow (CBF) pulsatility immediately, during, and after CA and resuscitation has not been investigated. We characterized the effects of asphyxial CA on short‐term (<2 hours after CA) CBF and femoral arterial blood pressure (ABP) pulsatility and studied their relationship to cerebrovascular resistance (CVR) and short‐term neuroelectrical recovery.

Methods and Results

Male rats underwent asphyxial CA followed by cardiopulmonary resuscitation. A multimodal platform combining laser speckle imaging, ABP, and electroencephalography to monitor CBF, peripheral blood pressure, and brain electrophysiology, respectively, was used. CBF and ABP pulsatility and CVR were assessed during baseline, CA, and multiple time points after resuscitation. Neuroelectrical recovery, a surrogate for neurological outcome, was assessed using quantitative electroencephalography 90 minutes after resuscitation. We found that CBF pulsatility differs significantly from baseline at all experimental time points with sustained deficits during the 2 hours of postresuscitation monitoring, whereas ABP pulsatility was relatively unaffected. Alterations in CBF pulsatility were inversely correlated with changes in CVR, but ABP pulsatility had no association to CVR. Interestingly, despite small changes in ABP pulsatility, higher ABP pulsatility was associated with worse neuroelectrical recovery, whereas CBF pulsatility had no association.

Conclusions

Our results reveal, for the first time, that CBF pulsatility and CVR are significantly altered in the short‐term postresuscitation period after CA. Nevertheless, higher ABP pulsatility appears to be inversely associated with neuroelectrical recovery, possibly caused by impaired cerebral autoregulation and/or more severe global cerebral ischemia.

Association Between Central Blood Pressure and Subclinical Cerebrovascular Disease in Older Adults

Elevated blood pressure (BP) level is one of the most consistently identified risk factors for silent brain disease. BP values obtained at the proximal segment of the aorta (central BP) are more directly involved than brachial BP in the pathogenesis of cardiovascular disease. However, the association between central BP and silent cerebrovascular disease has not been clearly established. Participants in the CABL (Cardiovascular Abnormalities and Brain Lesions) study (n=993; mean age, 71.7±9.3 years; 37.9% men) underwent 2-dimensional echocardiography, arterial wave reflection analysis for determination of central BPs, and brain magnetic resonance imaging. Central BPs were calculated from the radial pulse waveform. Subclinical silent cerebrovascular disease was defined as silent brain infarction and white matter hyperintensity volume. Both brachial (P=0.014) and central pulse pressure (P=0.026) were independently associated with silent brain infarctions after adjustment for clinical variables, but not adjusting for each other. None of the brachial BP values was associated with upper quartile of white matter hyperintensity volume in multivariable analysis. Both central systolic BP (P<0.001) and central pulse pressure (P<0.001) were significantly associated with upper quartile of white matter hyperintensity volume in multivariable analysis, even after adjustment for brachial BP. In a predominantly older population-based cohort, both brachial and central pulse pressure were independently associated with silent brain infarction. However, higher central systolic BP and central pulse pressure, but not brachial BP, were significantly associated with white matter hyperintensity volume.

Carotid pulse pressure and intima media thickness are independently associated with cerebral hemodynamic pulsatility in community-living older adults

Vascular aging is associated with markers of cerebrovascular impairment. Whether discrete characteristics of arterial structure and function have independent and/or additive effects on cerebral hemodynamics, however, is not completely understood. We examined the association of cerebral hemodynamics with common carotid artery intima-media thickness (IMT) and pulse pressure (PP) in 61 older adults with prevalent cardiometabolic risk but no history of cerebrovascular disease. We calculated pulsatility index (PI) and hypercapnic reactivity of the middle cerebral artery, as well as global blood flow through the extracranial arteries. The dominant effects were related to hemodynamic pulsatility. In adults with metabolic syndrome, PI was related to IMT (r = 0.48, P = 0.003) after adjustment for age and sex. Without metabolic syndrome, PI was directly related to PP (r = 0.63, P = 0.003). Across the whole cohort, PP [β (95%CI) = 0.42 (0.18, 0.67), P = 0.001] and IMT [0.42 (0.18, 0.67), P < 0.001] remained significant predictors of PI, after accounting for individual cardiometabolic risk factors. The independent and combined effects of IMT and PP were tested by binarizing PP and IMT at the sample median. Participants with both IMT and PP above their respective medians had elevated PI compared with those with both vascular markers below the median [median (interquartile range) = 1.06 (0.22) vs. 0.84 (0.14), P = 0.003)]. PI was not different from the low risk group if only one of IMT or PP were above the median. Although overall vascular burden was low, moderate associations with PI persisted, suggesting pulsatile characteristics represent one of the earliest markers linking vascular aging to changes in brain health.

Visit-to-Visit Fasting Glucose Variability in Young Adulthood and Hippocampal Integrity and Volume at Midlife

OBJECTIVE

To determine whether visit-to-visit fasting glucose (VVFG) variability in young adulthood is associated with midlife hippocampal integrity and volume.

RESEARCH DESIGN AND METHODS

Multivariable-adjusted linear regression models were used to estimate the association between VVFG variability and brain MRI variables in 543 CARDIA study participants. VVFG variability was defined by the SD of FG (SDFG), the coefficient of variation of the mean FG (CVFG), and the average real variability (ARVFG) over 25 years of follow-up. Hippocampal integrity fractional anisotropy (FA) and tissue volume standardized to intracranial volume were measured by 3T MRI at year 25.

RESULTS

After multivariable adjustment, higher FG variability (1-SD increase) was associated with lower hippocampal FA (SDFG -0.015 [95% CI -0.026, -0.004]; CVFG -0.009 [95% CI -0.018, -0.001]; ARVFG -0.011 [95% CI -0.019, -0.002]) and lower hippocampal volume (SDFG -0.012 [95% CI -0.023, -0.001]).

CONCLUSIONS

Higher VVFG variability in young adulthood is associated with lower midlife hippocampal integrity and volume, suggesting its value in predicting risk for hippocampal structural damage.

Education moderates the effects of large central artery aging on cognitive performance in middle-aged and older adults

Central artery aging, including elevated aortic stiffness, central blood pressure (BP), and pulse pressure (PP), is a novel risk factor for the development of age-associated cognitive dysfunction. Individuals with higher educational attainment may develop greater brain pathology prior to the onset of cognitive decline. However, whether education moderates relations between central artery aging and cognitive performance is unknown. We hypothesized that years of formal education would moderate the relation between central artery aging and cognitive performance in middle-aged/older (MA/O) adults (n = 113, age 67.3 ± 0.7 years). Significant interactions between education*central systolic BP (β = .21, p = .02) and education*central PP (β = .22, p = .01) demonstrated weaker associations between central BP and PP with processing speed performance in those with higher education. Similarly, education moderated the relation between aortic stiffness (carotid-femoral pulse wave velocity, cfPWV) and executive function performance (β = .21, p = .02). To test if the relation between central arterial aging and cognitive performance was captured by a predetermined education threshold, MA/O adults were secondarily categorized as ≤high school (HS) (i.e., ≤12 years, n = 36) or >HS (≥13 years, n = 77). Higher central systolic BP was associated with slower processing speed (≤HS: r = -.59, p < .001 vs. >HS: r = -.25, p = .03) and weaker executive function (r = -.39, p = .03 vs. r = -.32, p = .006). Higher cfPWV was selectively correlated with weaker executive function performance (r = -.39, p = .03) in ≤HS only and this association significantly differed between education groups. Educational attainment appears to moderate the adverse effects of central artery aging on cognitive performance among MA/O adults.

Blood Pressure Variability and Cerebral Small Vessel Disease: A Systematic Review and Meta-Analysis of Population-Based Cohorts

Background and Purpose- Blood pressure (BP) variability may increase the risk of stroke and dementia. It remains inconclusive whether BP variability is associated with cerebral small vessel disease, a common and potentially devastating subclinical disease that contributes significantly to both stroke and dementia. Methods- A systematic review and meta-analysis of prospective cohort studies that examined the association between BP variability and the presence or progression of established markers of cerebral small vessel disease, including white matter hyperintensities, lacunes, and microbleeds on magnetic resonance imaging. We searched MEDLINE, EMBASE, and Web of Science. Ten studies met the criteria for qualitative synthesis and 7 could be included in the meta-analysis. Data were synthetized using random-effect models. Results- These studies included a total of 2796 individuals aged 74 (mean) ±4 (SD) years, with a median follow-up of 4.0 years. A one SD increase in systolic BP variability was associated with increased odds of the presence or progression of white matter hyperintensities (odds ratio, 1.26 [95% CI, 1.06-1.50]). The association of systolic BP variability with the presence of lacunes (odds ratio, 0.93 [95% CI, 0.74-1.16]) and the presence of microbleeds (odds ratio, 1.13 [95% CI, 0.89-1.44]) were not statistically significant. Conclusions- A larger BP variability may be associated with a higher risk of having a higher burden of white matter hyperintensities. Targeting large BP variability has the potential to prevent cerebral small vessel disease and thereby reducing the risk of stroke and dementia. The potential issue of reverse causation and the heterogeneity in the assessment of cerebral small vessel disease markers should be better addressed in future studies.

Clinical Correlates of Aortic Stiffness and Wave Amplitude in Black Men and Women in the Community

Background

Black individuals have greater risk for cardiovascular disease (CVD) than whites. Identifying CVD risk factors associated with abnormal aortic hemodynamics in blacks may optimize CVD prevention and treatment strategies.

Methods and Results

Jackson Heart Study participants underwent applanation tonometry (2011–2016) with assessment of carotid‐femoral pulse wave velocity (CFPWV) and forward wave amplitude (FWA). CVD risk factors were assessed during examination 3 (2009–2012). We examined the association of risk factors with binary and continuous CFPWV and FWA in multivariable stepwise models. We evaluated for effect modification by sex to determine differential associations of risk factors with aortic hemodynamics in men and women. We examined 1322 individuals (mean age 66±11 years, 66% women). Age was strongly associated with elevated CFPWV (odds ratio, 4.76; 95% confidence interval, 3.84–5.89 [P<0.0001]) and FWA (odds ratio, 2.30; 95% CI, 1.98–2.69 [P<0.0001]). Men had greater odds of elevated CFPWV compared with women (odds ratio, 1.54; 95% confidence interval, 1.11–2.13 [P=0.009]). Heart rate, mean arterial pressure, and use of antihypertensive medications were associated with elevated CFPWV and FWA (all P≤0.02). Additionally, total/high‐density lipoprotein cholesterol and fasting glucose were associated with elevated CFPWV (both P≤0.002) and use of diabetes mellitus medications was associated with elevated FWA (P≤0.0001). We observed a steeper association of age and mean arterial pressure with unfavorable aortic hemodynamics in women than men.

Conclusions

In blacks in the community, differential CVD risk factors are associated with aortic stiffness and FWA. Future work may determine the impact of risk factor modification on abnormal central aortic hemodynamics and CVD outcomes.

Time-dependent impairments in learning and memory in Streptozotocin-induced hyperglycemic rats

The sedentary lifestyle is responsible for the high prevalence of diabetes which also impairs cognition including learning and memory. Various studies have highlighted the learning and memory impairments in rodent models but data regarding the timeline of their development and their correlation to biochemical parameters are scarce. So, the present study was designed to investigate the type of memory which is more susceptible to hyperglycemia and its correlation with biochemical parameters such as inflammatory cytokines, cAMP response element binding (CREB) and protein kinase B (Akt) activation. Hyperglycemia was induced using streptozotocin (STZ, 45 mg/kg i.p.) and confirmed by measuring fasting blood glucose levels after 1 week of STZ injection. Learning and memory deficits were evaluated using the Novel Object Recognition Test (NORT) and Morris water maze (MWM), and correlated with biochemical parameters (TNF-α, IL-1β, and dopamine) at 3, 6 and 9 weeks. STZ-injected rats after 3 weeks of injection demonstrated moderate hyperglycemia (blood glucose = 7.99 ± 0.62 mM) with intact learning and reference memory; however, their working memory was impaired in MWM. Severe hyperglycemia (blood glucose = 11.51 ± 0.69 mM) accompanied by impaired short, long, and working memory was evident after 6 weeks whereas learning was intact. After 9 weeks of STZ injection, hyperglycemia was more pronounced (13.69 ± 1.43 mM) and accompanied by a learning deficit in addition to short, long, and working memory impairments. The extent of hyperglycemia either in terms of duration or severity resulted in enhanced inflammation, down-regulation of the level of dopamine, protein expression of AKT and CREB, which possibly affected learning and memory negatively.

Arterial stiffness and brain integrity: A review of MRI findings

BACKGROUND

Given the increasing incidence of vascular diseases and dementia, a better understanding of the cerebrovascular changes induced by arterial stiffness is important for early identification of white and gray matter abnormalities that might antedate the appearance of clinical cognitive symptoms. Here, we review the evidence from neuroimaging demonstrating the impact of arterial stiffness on the aging brain.

METHOD

This review presents findings from recent studies examining the association between arterial stiffness, cognitive function, cerebral hypoperfusion, and markers of neuronal fiber integrity using a variety of MRI techniques.

RESULTS

Overall, changes associated with arterial stiffness indicates that the corpus callosum, the internal capsule and the corona radiata may be the most vulnerable regions to microvascular damage. In addition, the microstructural integrity of these regions appears to be associated with cognitive performance. Changes in gray matter structure have also been found to be associated with arterial stiffness and are present as early as the 5th decade. Moreover, low cerebral perfusion has been associated with arterial stiffness as well as lower cognitive performance in age-sensitive tasks such as executive function.

CONCLUSION

Considering the established relationship between arterial stiffness, brain and cognition, this review highlights the need for future studies of brain structure and function in aging to implement measurements of arterial stiffness in parallel with quantitative imaging.

Differential Effect of APOE ɛ4 Status and Elevated Pulse Pressure on Functional Decline in Cognitively Normal Older Adults

BACKGROUND/OBJECTIVE

The APOE ɛ4 allele and increased vascular risk have both been independently linked to cognitive impairment and dementia. Since few studies have characterized how these risk factors affect everyday functioning, we investigated the relationship between APOE ɛ4 genotype and elevated pulse pressure (PP) on functional change in cognitively normal participants from the Alzheimer's Disease Neuroimaging Initiative (ADNI).

METHODS

738 normally aging participants underwent APOE genotyping, and baseline PP was calculated from blood pressure indices. The Functional Activities Questionnaire (FAQ) was completed by participants' informant at baseline and 6, 12, 24, 36, and 48-month follow-up visits. Multiple linear regression and multilevel modeling were used to examine the effects of PP and APOE ɛ4 genotype on cross-sectional and longitudinal FAQ scores, respectively.

RESULTS

Adjusting for demographic and clinical covariates, results showed that both APOE ɛ4 status and elevated PP predicted greater functional difficulty trajectories across four years of follow-up. Interestingly, however, elevated PP was associated with greater functional decline over time in ɛ4 non-carriers versus carriers.

CONCLUSION

Results show that, although APOE ɛ4 status is the prominent predictor of functional difficulty for ɛ4 carriers, an effect of arterial stiffening on functional difficulty was observed in non-carriers. Future studies are needed in order to clarify the etiology of the association between PP and different brain aging processes, and further explore its utility as a marker of dementia risk. The present study underscores the importance of targeting modifiable risk factors such as elevated PP to prevent or slow functional decline and pathological brain aging.

Arterial stiffness relates to executive dysfunction in later life

Cardiovascular disease in older people is often linked with cognitive impairment, particularly in domains of executive function and processing speed. Our aims examined whether carotid-femoral pulse wave velocity (PWV) related to subtle changes of executive function and processing speed. Fifty-six individuals with subjective mood and/or cognitive concerns underwent PWV and neuropsychological assessments of processing speed (Trail Making Test Part A) and executive functioning (Delis Kaplan Executive Function System Stroop Task; Trail Making Test Part B, TMT-B). Individuals with high PWV (≥12.0m/s) had poorer performance on TMT-B, compared to low PWV (<12.0m/s), and a moderate negative correlation (r = -0.38, p = .004) between PWV and TMT-B performance. Our results confirm that in older adults at-risk for cognitive decline, early markers of CVD are associated with subtle decrements in rapid set-shifting (executive function), supporting efforts towards early detection of CVD as a secondary prevention strategy for older individuals with cognitive decline.

Plasma Vitamin C Concentrations and Cognitive Function: A Cross-Sectional Study

Vitamin-C is a water soluble molecule that humans have lost the ability to produce. Vitamin-C plays a role in CNS functions such as neuronal differentiation, maturation, myelin formation and modulation of the catecholaminergic systems. A recent systematic review by our team indicated the need for further research into the relationship between plasma vitamin C and cognition in cognitively intact participants using plasma vitamin C concentrations instead of estimates derived from food-frequency-questionnaires (FFQ), and more sensitive cognitive assessments suitable for cognitive abilities vulnerable to aging. It was hypothesized that higher plasma vitamin C concentrations would be linked with higher cognitive performance. This cross-sectional trial was conducted on healthy adults (n = 80, Female = 52, Male = 28, 24-96 years) with a range of plasma Vitamin C concentrations. Cognitive assessments included The Swinburne-University-Computerized-Cognitive-Assessment-Battery (SUCCAB) and two pen and paper tests, the Symbol-Digits-Modalities-Test (SDMT) and Hopkins-Verbal-Learning-Test-Revised (HVLT-R). The pen and paper assessments were conducted to establish whether their scores would correlate with the computerized tasks. Plasma-Vitamin C concentrations were measured using two biochemical analyses. Participants were grouped into those with plasma vitamin-C concentrations of adequate level (≥28 μmol/L) and deficient level (<28 μmol/L). The SUCCAB identified a significantly higher performance ratio (accuracy/reaction-time) in the group with adequate vitamin-C levels vs. deficient vitamin-C on the choice reaction time (M = 188 ± 4 vs. 167 ± 9, p = 0.039), immediate recognition memory (M = 81 ± 3 vs. 68 ± 6, p = 0.03), congruent Stroop (M = 134 ± 3 vs. 116 ± 7, p = 0.024), and delayed recognition tasks (M = 72 ± 2 vs. 62 ± 4, p = 0.049), after adjusting for age (p < 0.05). Significantly higher scores in immediate recall on the HVLT-R (M = 10.64 ± 0.16 vs. 9.17 ± 0.37, p = 0.001), delayed recall (M = 9.74 ± 0.22 vs. 7.64 ± 0.51, p < 0.001), total recall (M = 27.93 ± 0.48 vs. 24.19 ± 1.11, p = 0.003) were shown in participants with adequate plasma Vitamin-C concentrations, after adjusting for vitamin-C supplementation dose (p < 0.05). Similarly, higher SDMT scores were observed in participants with adequate plasma Vitamin-C concentrations (M = 49.73 ± 10.34 vs. 41.38 ± 5.06, p = 0.039), after adjusting for age (p < 0.05). In conclusion there was a significant association between vitamin-C plasma concentrations and performance on tasks involving attention, focus, working memory, decision speed, delayed and total recall, and recognition. Plasma vitamin C concentrations obtained through vitamin C supplementation did not affect cognitive performance differently to adequate concentrations obtained through dietary intake. Clinicaltrials.gov Unique Identifier: ACTRN 12615001140549, URL: https://www.anzctr.org.au/Trial/Registration/TrialReview.aspx?id=369440.

Brain arterial dilatation modifies the association between extracranial pulsatile hemodynamics and brain perivascular spaces: the Northern Manhattan Study

Pulsatile hemodynamics are associated with brain small perivascular spaces (SPVS). It is unknown whether the stiffness of intermediary arteries connecting the aorta and brain modifies this association. Participants from the Northern Manhattan Study were assessed for SPVS (defined as ≤3 mm T1 voids) and white matter hyperintensity volume (WMH) using MRI. Middle (MCA) and anterior cerebral arterial (ACA) diameters (measured on time-of-flight MRA) and CCA strain (assessed by ultrasound) were used as surrogates of stiffness. Brachial and aortic pulse pressure (PP) and aortic augmentation index (Aix, assessed by applanation tonometry) were used as markers of pulsatility. We tested whether stiffness in intermediary arteries modifies the association between extracranial pulsatility with SPVS and WMH. We found that among 941 participants (mean age 71 ± 9 years, 60% women, 66% Hispanic), the right MCA/ACA diameter was associated with right anterior SPVS (B = 0.177, P = 0.002). Brachial PP was associated with right anterior SPVS (B = 0.003, P = 0.02), and the effect size was bigger with right MCA/ACA diameter in the upper tertile (P = 0.001 for the interaction). The association between right CCA strain and ipsilateral SPVS was modified by MCA/ACA diameter, with the largest effect size in those with ipsilateral MCA/ACA diameter in the upper tertile (P = 0.001 for the interaction). Similar dose-effects and statistical interactions were replicated using aortic AIx or aortic PP. We found no evidence of effect modification between pulsatile measures and WMH by stiffness measures. In summary, pulsatile hemodynamics relate to brain SPVS, and the association is the strongest among individuals with dilated brain arteries.

Brain arterial dilatation and the risk of Alzheimer's disease

INTRODUCTION

We tested the hypothesis that brain arterial dilatation increases the risk of Alzheimer's dementia (AD).

METHODS

We studied dementia-free participants in the Washington Heights-Inwood Columbia Aging Project who had a brain MRI and post-MRI dementia adjudication. We measured the axial T2-proton density diameters of the intracranial carotids and basilar diameters and used Cox models to obtain AD hazard ratios and 95% intervals.

RESULTS

Of 953 participants (mean age 77 ± 7 y, women 64%, 71% nonwhite) followed on average for 3 ± 3 years, 76 (8%) developed AD. In a model adjusted for demographics, vascular risks, apolipoprotein E (APOE)-ε4, and white matter hyperintensities, larger carotid diameters increased the risk of AD, defined categorically as ≥ 90th percentile (HR 4.34, 1.70-11.11) or continuously (HR 1.44 per SD, 1.07-1.94).

DISCUSSION

Understanding the pathophysiology of the association between AD and brain arterial dilatation may reveal new clues to the vascular contributions to AD.

Incorporation of Novel Vascular Measures into Clinical Management: Recent Insights from the Framingham Heart Study

PURPOSE OF REVIEW

The review discusses evidence from the Framingham Heart Study that supports the assessment and utility of novel vascular and blood pressure measures to inform clinical management of blood pressure-related cardiovascular disease.

RECENT FINDINGS

Recent Framingham Heart Study investigations provide new insights into the associations of novel and traditional vascular and blood pressure measures, such as measures of aortic stiffness, components of blood pressure waves, and orthostatic change in blood pressure, with cardiovascular disease events and brain structure and function. Novel vascular measures provide opportunities for additional investigation and potential development of new interventions that are more precisely targeted at underlying pathophysiology. Inclusion of novel vascular measures should be considered in clinical practice to screen for early, subclinical disease and to stratify high-risk individuals for targeted therapies.

Carotid Flow Velocities and Blood Pressures Are Independently Associated With Cognitive Function

BACKGROUND

Few studies simultaneously addressed associations between carotid flow velocities, blood pressure (BP), and cognitive function.

MATERIALS AND METHODS

Subject without dementia (N = 1,684) underwent measurements of BP and biochemical markers. Mini-Mental State Examination (MMSE) and comprehensive neuropsychological tests were used to evaluate cognitive function. Peak systolic velocity (PSV) and end-diastolic velocity (EDV) were measured in common and internal carotid artery. Subjects with MMSE score of ≤24 (25th percentile) was defined as low MMSE. Multivariable linear and logistic regression were used to evaluate the relationship of cognitive function with carotid flow velocities and BP.

RESULTS

Carotid flow velocities (PSV: standardized β = 0.067, P = 0.0009; and EDV: standardized β = 0.067, P = 0.0021) and systolic blood pressure (standardized β = -0.061, P = 0.005) were positively and negatively associated with MMSE, respectively, in the model with adjustments for age, sex, educational attainment, nutritional status, and smoking. Similar trends were noted for the associations between flow velocities and different neuropsychological tests. By multivariable logistic regression, the group with the lowest quartile (<25th percentile) of flow velocities had increased probability of low MMSE (odds ratio: 1.538; 95% confidence intervals: 1.142 to 2.071, P = 0.0046 for PSV; and odds ratio: 1.699; 95% confidence intervals: 1.233 to 2.341; P = 0.0012 for EDV), compared to those with the highest quartile (≥75th) flow velocities.

CONCLUSION

Both low carotid flow velocity and high BP were independently and comparably associated with cognitive dysfunction.

Quantifying cardiac-induced brain tissue expansion using DENSE

Brain tissue undergoes viscoelastic deformation and volumetric strain as it expands over the cardiac cycle due to blood volume changes within the underlying microvasculature. Volumetric strain measurements may therefore provide insights into small vessel function and tissue viscoelastic properties. Displacement encoding via stimulated echoes (DENSE) is an MRI technique that can quantify the submillimetre displacements associated with brain tissue motion. Despite previous studies reporting brain tissue displacements using DENSE and other MRI techniques, a complete picture of brain tissue volumetric strain over the cardiac cycle has not yet been obtained. To address this need we implemented 3D cine-DENSE at 7 T and 3 T to investigate the feasibility of measuring cardiac-induced volumetric strain as a marker for small vessel blood volume changes. Volumetric strain over the entire cardiac cycle was computed for the whole brain and for grey and white matter tissue separately in six healthy human subjects. Signal-to-noise ratio (SNR) measurements were used to determine the voxel-wise volumetric strain noise. Mean peak whole brain volumetric strain at 7 T (mean ± SD) was (4.5 ± 1.0) × 10^-4 (corresponding to a volume expansion of 0.48 ± 0.1 mL), which is in agreement with literature values for cerebrospinal fluid that is displaced into the spinal canal to maintain a stable intracranial pressure. The peak volumetric strain ratio of grey to white matter was 4.4 ± 2.8, reflecting blood volume and tissue stiffness differences between these tissue types. The mean peak volumetric strains of grey and white matter tissue were found to be significantly different (p < 0.001). The mean SNR at 7 T and 3 T of the DENSE measurements was 22.0 ± 7.3 and 7.0 ± 2.8 respectively, which currently limits a voxel-wise strain analysis at both field strengths. We demonstrate that tissue specific quantification of volumetric strain is feasible with DENSE. This metric holds potential for studying blood volume pulsations in the ageing brain in healthy and diseased states.