Endothelial function and white matter hyperintensities in older adults with cardiovascular disease

Cerebrovascular Endothelial Dysfunction: Role of BACE1

Dysfunctional endothelium is increasingly recognized as a mechanistic link between cardiovascular risk factors and dementia, including Alzheimer disease. BACE1 (β-site amyloid-β precursor protein-cleaving enzyme 1) is responsible for β-processing of APP (amyloid-β precursor protein), the first step in the production of Aβ (amyloid-β) peptides, major culprits in the pathogenesis of Alzheimer disease. Under pathological conditions, excessive activation of BACE1 exerts detrimental effects on endothelial function by Aβ-dependent and Aβ-independent mechanisms. High local concentration of Aβ in the brain blood vessels is responsible for the loss of key vascular protective functions of endothelial cells. More recent studies recognized significant contribution of Aβ-independent proteolytic activity of endothelial BACE1 to the pathogenesis of endothelial dysfunction. This review critically evaluates existing evidence supporting the concept that excessive activation of BACE1 expressed in the cerebrovascular endothelium impairs key homeostatic functions of the brain blood vessels. This concept has important therapeutic implications. Indeed, improved understanding of the mechanisms of endothelial dysfunction may help in efforts to develop new approaches to the protection and preservation of healthy cerebrovascular function.

Hypertension, Neurodegeneration, and Cognitive Decline

Elevated blood pressure is a well-established risk factor for age-related cognitive decline. Long linked to cognitive impairment on vascular bases, increasing evidence suggests a potential association of hypertension with the neurodegenerative pathology underlying Alzheimer disease. Hypertension is well known to disrupt the structural and functional integrity of the cerebral vasculature. However, the mechanisms by which these alterations lead to brain damage, enhance Alzheimer pathology, and promote cognitive impairment remain to be established. Furthermore, critical questions concerning whether lowering blood pressure by antihypertensive medications prevents cognitive impairment have not been answered. Recent developments in neurovascular biology, brain imaging, and epidemiology, as well as new clinical trials, have provided insights into these critical issues. In particular, clinical and basic findings on the link between neurovascular dysfunction and the pathobiology of neurodegeneration have shed new light on the overlap between vascular and Alzheimer pathology. In this review, we will examine the progress made in the relationship between hypertension and cognitive impairment and, after a critical evaluation of the evidence, attempt to identify remaining knowledge gaps and future research directions that may advance our understanding of one of the leading health challenges of our time.

Subthalamic deep brain stimulation improves vascular endothelial function in Parkinson's disease

OBJECTIVES

Vascular health (white matter change, vascular risk factor, angiogenesis, microvascular alteration) is associated with clinical progression or levodopa-induced dyskinesia in PD. Vascular endothelial function is known to reflect the earliest vascular change. While DBS can improve motor and non-motor symptoms, the effect of DBS on vascular endothelial function is unknown. Thus, we aimed to investigate whether DBS surgery could impact vascular endothelial function in PD.

METHOD

A total of 20 PD patients were recruited. Vascular endothelial function was evaluated with flow-mediated dilation (FMD). FMD was investigated before and after one year of DBS surgery.

RESULTS

FMD improved (6.01 ± 1.58 to 6.84 ± 1.57, p = 0.027). While the level of homocysteine slightly decreased (13.8 ± 4.1 to 13.0 ± 3.2, p = 0.05), there was no significant correlation between FMD changes and homocysteine levels (r = 0.42, p = 0.065). FMD change was associated with baseline age (r = -0.59, p = 0.006) but not with disease duration (p = 0.73), baseline UPDRS III (p = 0.81), change of UPDRS III and dyskinesia, and LEDD change (p = 0.94). Multivariate linear regression analysis revealed that only age (B = -0.139; p = 0.024) was significantly and inversely correlated with the change of FMD.

CONCLUSIONS

We found that STN-DBS improves vascular endothelial function in PD. Further studies are needed to clarify the exact pathogenesis and clinical implication of beneficial effects on vascular endothelial dysfunction in PD.

Association between lipid variability and the risk of mortality in cancer patients not receiving lipid-lowering agents

Aim

We investigated the association between total cholesterol (TC), low-density lipoprotein (LDL) cholesterol, high-density lipoprotein (HDL) cholesterol, and triglyceride (TG) variability and cancer patient mortality risk.

Methods

We retrospectively analyzed 42,539 cancer patients who were not receiving lipid-lowering agents and who had at least three TC measurements within 2 years of their initial cancer diagnosis. Using a multivariable Cox regression model, the risk of mortality was evaluated.

Results

In multivariable analysis, Q2 (adjusted hazard ratio [aHR]: 1.32, 95% confidence interval (CI): 1.24-1.41), Q3 (aHR: 1.66, 95% CI: 1.56-1.76), and Q4 (aHR: 1.96, 95% CI: 1.84-2.08) of coefficient of variation (CV) in TC were significantly associated with mortality risk compared to Q1, showing a linear association between higher TC variability and mortality (P for trend<0.001). Q2 (aHR: 1.34, 95% CI: 1.06-1.77), Q3 (aHR: 1.40, 95% CI: 1.06-1.85), and Q4 (aHR: 1.50, 95% CI: 1.14-1.97) were all significantly associated with a higher risk of death compared to Q1 in multivariable Cox regression for the association between CV in LDL and all-cause mortality (P for trend=0.005).

Conclusion

In cancer patients who do not receive lipid-lowering agents, high variability in total cholesterol and LDL cholesterol levels was found to pose significant role in mortality risk.

Early therapeutic effects of an Angiopoietin-1 mimetic peptide in middle-aged rats with vascular dementia

Background

Vascular Dementia (VaD) refers to dementia caused by cerebrovascular disease and/or reduced blood flow to the brain and is the second most common form of dementia after Alzheimer's disease. We previously found that in middle-aged rats subjected to a multiple microinfarction (MMI) model of VaD, treatment with AV-001, a Tie2 receptor agonist, significantly improves short-term memory, long-term memory, as well as improves preference for social novelty compared to control MMI rats. In this study, we tested the early therapeutic effects of AV-001 on inflammation and glymphatic function in rats subjected to VaD.

Methods

Male, middle-aged Wistar rats (10-12 m), subjected to MMI, were randomly assigned to MMI and MMI + AV-001 treatment groups. A sham group was included as reference group. MMI was induced by injecting 800 ± 200, 70-100 μm sized, cholesterol crystals into the internal carotid artery. Animals were treated with AV-001 (1 μg/Kg, i.p.) once daily starting at 24 h after MMI. At 14 days after MMI, inflammatory factor expression was evaluated in cerebrospinal fluid (CSF) and brain. Immunostaining was used to evaluate white matter integrity, perivascular space (PVS) and perivascular Aquaporin-4 (AQP4) expression in the brain. An additional set of rats were prepared to test glymphatic function. At 14 days after MMI, 50 μL of 1% Tetramethylrhodamine (3 kD) and FITC conjugated dextran (500 kD) at 1:1 ratio were injected into the CSF. Rats (4-6/group/time point) were sacrificed at 30 min, 3 h, and 6 h from the start of tracer infusion, and brain coronal sections were imaged using a Laser scanning confocal microscope to evaluate tracer intensities in the brain.

Result

Treatment of MMI with AV-001 significantly improves white matter integrity in the corpus callosum at 14 days after MMI. MMI induces significant dilation of the PVS, reduces AQP4 expression and impairs glymphatic function compared to Sham rats. AV-001 treatment significantly reduces PVS, increases perivascular AQP4 expression and improves glymphatic function compared to MMI rats. MMI significantly increases, while AV-001 significantly decreases the expression of inflammatory factors (tumor necrosis factor-α (TNF-α), chemokine ligand 9) and anti-angiogenic factors (endostatin, plasminogen activator inhibitor-1, P-selectin) in CSF. MMI significantly increases, while AV-001 significantly reduces brain tissue expression of endostatin, thrombin, TNF-α, PAI-1, CXCL9, and interleukin-6 (IL-6).

Conclusion

AV-001 treatment of MMI significantly reduces PVS dilation and increases perivascular AQP4 expression which may contribute to improved glymphatic function compared to MMI rats. AV-001 treatment significantly reduces inflammatory factor expression in the CSF and brain which may contribute to AV-001 treatment induced improvement in white matter integrity and cognitive function.

Differential association of endothelial function with brain structure in youth with versus without bipolar disorder

BACKGROUND

Mood symptoms and disorders are associated with impaired endothelial function, a marker of early atherosclerosis. Given the increased vascular burden and neurostructural differences among individuals with mood disorders, we investigated the endothelial function and brain structure interface in relation to youth bipolar disorder (BD).

METHODS

This cross-sectional case-controlled study included 115 youth, ages 13-20 years (n = 66 BD; n = 49 controls [CG]). Cortical thickness and volume for regions of interest (ROI; insular cortex, ventrolateral prefrontal cortex [vlPFC], temporal lobe) were acquired from FreeSurfer processed T1-weighted MRI images. Endothelial function was assessed using pulse amplitude tonometry, yielding a reactive hyperemia index (RHI). ROI and vertex-wise analyses controlling for age, sex, obesity, and intracranial volume investigated for RHI-neurostructural associations, and RHI-by-diagnosis interactions.

RESULTS

In ROI analyses, higher RHI (i.e., better endothelial function) was associated with lower thickness in the insular cortex (β = -0.19, p_FDR = 0.03), vlPFC (β = -0.30, p_FDR = 0.003), and temporal lobe (β = -0.22, p_FDR = 0.01); and lower temporal lobe volume (β = -0.16, p_FDR = 0.01) in the overall sample. In vertex-wise analyses, higher RHI was associated with lower cortical thickness and volume in the insular cortex, prefrontal cortex (e.g., vlPFC), and temporal lobe. Additionally, higher RHI was associated with lower vlPFC and temporal lobe volume to a greater extent in youth with BD vs. CG.

CONCLUSIONS

Better endothelial function was associated with lower regional brain thickness and volume, contrasting the hypothesized associations. Additionally, we found evidence that this pattern was exaggerated in youth with BD. Future studies examining the direction of the observed associations and underlying mechanisms are warranted.

Simulating the multicausality of Alzheimer's disease with system dynamics

INTRODUCTION

In Alzheimer's disease (AD), cognitive decline is driven by various interlinking causal factors. Systems thinking could help elucidate this multicausality and identify opportune intervention targets.

METHODS

We developed a system dynamics model (SDM) of sporadic AD with 33 factors and 148 causal links calibrated with empirical data from two studies. We tested the SDM's validity by ranking intervention outcomes on 15 modifiable risk factors to two sets of 44 and 9 validation statements based on meta-analyses of observational data and randomized controlled trials, respectively.

RESULTS

The SDM answered 77% and 78% of the validation statements correctly. Sleep quality and depressive symptoms yielded the largest effects on cognitive decline with which they were connected through strong reinforcing feedback loops, including via phosphorylated tau burden.

DISCUSSION

SDMs can be constructed and validated to simulate interventions and gain insight into the relative contribution of mechanistic pathways.

The effect of levodopa treatment on vascular endothelial function in Parkinson's disease

OBJECTIVE

There has been increasing awareness that micro-vascular alteration or vascular inflammation has been associated with levodopa-induced dyskinesia in PD. Vascular endothelial function assessed by flow mediated dilation (FMD) is known to reflect early microvascular change. We compare the impact of levodopa or dopamine agonist treatment on the change of FMD in de novo PD patients.

METHODS

This retrospective study used a selected sample from registry. We identified de-novo PD patients who underwent FMD at baseline, and follow-up FMD after 1 year (± 2 month) of levodopa (n = 18) or dopamine agonist (n = 18) treatment.

RESULTS

FMD decreased after levodopa (8.60 ± 0.46 to 7.21 ± 0.4, p = 0.002) but there were no significant changes after DA treatment (8.33 ± 0.38 to 8.22 ± 0.33, p = 0.26). Homocysteine rose (11.52 ± 0.45 to 14.33 ± 0.68, p < 0.05) during levodopa treatment, but dopamine agonist had no effect (10.59 ± 0.38 to 11.38 ± 0.67, p = 0.184). Correlation analysis revealed that the changes in homocysteine level had non-significant correlation with FMD change (r =  - 0.30, p = 0.06). FMD change was not associated with age (p = 0.47), disease duration (p = 0.81), baseline motor UPDRS (p = 0.43), motor UPDRS change (p = 0.64), levodopa equivalent dose change (p = 0.65).

CONCLUSIONS

We found that 1-year levodopa treatment may adversely affect vascular endothelial function in de novo PD. Further studies are needed to clarify the exact pathogenesis and clinical implication of levodopa-induced endothelial dysfunction in PD.

Cardiovascular profiles associated with white matter hyperintensities in healthy young women

Women who experience hypertension in pregnancy have increased risk of both chronic hypertension and dementia. High blood pressure is associated with increased evidence of white matter hyperintensities (WMH) in brain imaging. WMH are disruptions of the white matter of the brain that occur with demyelination and axonal degeneration, are associated with vascular disease, occur more frequently in people with hypertension, and are associated with cognitive impairment. We evaluated the relationship between WMH and subclinical cardiovascular function in healthy young nulliparous women and women with a history of early-onset preeclampsia. Sixty-two reproductive-aged women were assessed during the follicular phase of the menstrual cycle after a 3-day sodium/potassium-controlled diet. Half of participants had a history of early-onset preeclampsia, and half were nulliparous. Blood was drawn to assess inflammatory markers. Cardiovascular assessments included tonometric blood pressure monitoring, volume loading to assess vascular compliance, echocardiography to assess cardiac ejection time, brachial pulse wave velocity of the brachial artery, assessing cardiovascular stiffness, and brachial artery flow mediated vasodilation to assess endothelial mediated dilatory response. T2 fluid-attenuated inversion recovery (FLAIR) MRI imaging was obtained. Two raters, blinded to cardiovascular assessments and pregnancy history, reviewed MRI scans for evidence of WMH using the Fazekas rating scale. WMHs were detected in 17 women; 45 had normal white matter structure. Participants with Fazekas score>0 had exaggerated response to volume loading compared to women with a Fazekas score of 0 and longer cardiac ejection times. Fazekas scores >0 had lower brachial flow-mediated vasodilation and increased white blood count compared to those with no evidence of WMH. Women with WMH had reduced cardiovascular compliance, and a trend towards decreased endothelial responsiveness compared to those without WMH. These data demonstrated that the relationship between cardiovascular and brain health was detectable in young, healthy, reproductive-aged women, and may play a role in later development of clinical disease. These findings may help identify women who are at risk for cognitive decline and pathological aging.

Hypertension, Neurovascular Dysfunction, and Cognitive Impairment

Hypertension affects a significant proportion of the adult and aging population and represents an important risk factor for vascular cognitive impairment and late-life dementia. Chronic high blood pressure continuously challenges the structural and functional integrity of the cerebral vasculature, leading to microvascular rarefaction and dysfunction, and neurovascular uncoupling that typically impairs cerebral blood supply. Hypertension disrupts blood-brain barrier integrity, promotes neuroinflammation, and may contribute to amyloid deposition and Alzheimer pathology. The mechanisms underlying these harmful effects are still a focus of investigation, but studies in animal models have provided significant molecular and cellular mechanistic insights. Remaining questions relate to whether adequate treatment of hypertension may prevent deterioration of cognitive function, the threshold for blood pressure treatment, and the most effective antihypertensive drugs. Recent advances in neurovascular biology, advanced brain imaging, and detection of subtle behavioral phenotypes have begun to provide insights into these critical issues. Importantly, a parallel analysis of these parameters in animal models and humans is feasible, making it possible to foster translational advancements. In this review, we provide a critical evaluation of the evidence available in experimental models and humans to examine the progress made and identify remaining gaps in knowledge.

Exercise as therapy for neurodevelopmental and cognitive dysfunction in people with a Fontan circulation: A narrative review

People with a Fontan circulation are at risk of neurodevelopmental delay and disability, and cognitive dysfunction, that has significant implications for academic and occupational attainment, psychosocial functioning, and overall quality of life. Interventions for improving these outcomes are lacking. This review article discusses current intervention practices and explores the evidence supporting exercise as a potential intervention for improving cognitive functioning in people living with a Fontan circulation. Proposed pathophysiological mechanisms underpinning these associations are discussed in the context of Fontan physiology and avenues for future research are recommended.

Association between visit-to-visit lipid variability and incident cancer: a population-based cohort study

Dyslipidaemia is associated with increased cancer risk. However, the prognostic value of visit-to-visit lipid variability (VVLV) is unexplored in this regard. To investigate the associations between VVLV and the risk of incident cancer, we conducted a retrospective cohort study on adult patients attending a family medicine clinic in Hong Kong during 2000-2003, excluding those with <3 tests for low-density lipoprotein cholesterol (LDL-C), high-density lipoprotein cholesterol (HDL-C), triglycerides, and total cholesterol (TC) each, those with prior cancer diagnosis, and those with <1 year of follow-up. Visit-to-visit LDL-C, HDL-C, TC, and triglycerides variabilities were measured by the coefficient of variation (CV). Patients were followed up until 31^st December 2019 for the primary outcome of incident cancer. Altogether, 69,186 patients were included (26,679 males (38.6%); mean age 60±13 years; mean follow-up 16±3 years); 7958 patients (11.5%) had incident cancer. Higher variability of LDL-C, HDL-C, TC, and TG was associated with higher risk of incident cancer. Patients in the third tercile of the CV of LDL-C (adjusted hazard ratio (aHR) against first tercile 1.06 [1.00, 1.12], p=0.049), HDL-C (aHR 1.37 [1.29, 1.44], p<0.001), TC (aHR 1.10 [1.04, 1.17], p=0.001), and TG (aHR 1.11 [1.06, 1.18], p<0.001) had the highest risks of incident cancer. Among these, only HDL-C variability remained associated with the risk of incident cancer in users of statins/fibrates. To conclude, higher VVLV was associated with significantly higher long-term risks of incident cancer. VVLV may be a clinically useful tool for cancer risk stratification.

The Influence of Serum Uric Acid on the Brain and Cognitive Dysfunction

Uric acid is commonly known for its bad reputation. However, it has been shown that uric acid may be actively involved in neurotoxicity and/or neuroprotection. These effects could be caused by oxidative stress or inflammatory processes localized in the central nervous system, but also by other somatic diseases or systemic conditions. Our interest was to summarize and link the current data on the possible role of uric acid in cognitive functioning. We also focused on the two putative molecular mechanisms related to the pathological effects of uric acid-oxidative stress and inflammatory processes. The hippocampus is a prominent anatomic localization included in expressing uric acid's potential impact on cognitive functioning. In neurodegenerative and mental disorders, uric acid could be involved in a variety of ways in etiopathogenesis and clinical presentation. Hyperuricemia is non-specifically observed more frequently in the general population and after various somatic illnesses. There is increasing evidence to support the hypothesis that hyperuricemia may be beneficial for cognitive functioning because of its antioxidant effects but may also be a potential risk factor for cognitive dysfunction, in part because of increased inflammatory activity. In this context, gender specificities must also be considered.

Pathogeneses and Imaging Features of Cerebral White Matter Lesions of Vascular Origins

White matter lesion (WML), also known as white matter hyperintensities or leukoaraiosis, was first termed in 1986 to describe the hyperintense signals on T2-weighted imaging (T2WI) and fluid-attenuated inversion recovery (FLAIR) maps. Over the past decades, a growing body of pathophysiological findings regarding WMLs have been discovered and discussed. Currently, the generally accepted WML pathogeneses mainly include hypoxia-ischemia, endothelial dysfunction, blood-brain barrier disruption, and infiltration of inflammatory mediators or cytokines. However, none of them can explain the whole dynamics of WML formation. Herein, we primarily focus on the pathogeneses and neuroimaging features of vascular WMLs. To achieve this goal, we searched papers with any type published in PubMed from 1950 to 2020 and cross-referenced the keywords including “leukoencephalopathy”, “leukoaraiosis”, “white matter hyperintensity”, “white matter lesion”, “pathogenesis”, “pathology”, “pathophysiology”, and “neuroimaging”. Moreover, references of the selected articles were browsed and searched for additional pertinent articles. We believe this work will supply the robust references for clinicians to further understand the different WML patterns of varying vascular etiologies and thus make customized treatment.

Age Moderates Associations of Hypertension, White Matter Hyperintensities, and Cognition

BACKGROUND

Hypertension and white matter hyperintensities (WMH) are mutually associated risk factors for cognitive impairment. However, age may modify the associations between hypertension and WMH, and their links to cognitive impairment.

OBJECTIVE

We evaluated the interaction between age and hypertension on WMH, and the age-stratified associations of hypertension and WMH with cognition.

METHODS

Key measures include systolic blood pressure (SBP), WMH (modified Fazekas visual ratings of cranial MRI), and the Montreal Cognitive Assessment (MoCA). Participants (N = 488) with prodromal and mild dementia were age-stratified (≤49, 50-59, 60-69,≥70), and considered hypertensive if their SBP≥140 mmHg. The interaction between age strata and hypertension on WMH, and age-stratified associations of hypertension and WMH with cognition, were evaluated using multiple linear regression analyses. Analyses controlled for other risk factors for WMH and cognitive impairment.

RESULTS

Age moderated the association between SBP and WMH. Hypertension was associated with higher WMH only in those aged 60-69, and WMH trends across age bands differed between those with and without hypertension. Finally, WMH and SBP≥140 were independently associated with lower MoCA scores within the 50-59 age band, while WMH alone was associated with poorer MoCA scores in the≥70 age band.

CONCLUSION

In adults with prodromal or mild dementia, hypertension was associated with WMH specifically in the 60-69 age strata. Associations between hypertension and WMH with poorer cognition also differed across age bands. Future studies will be needed to investigate whether blood pressure management to slow cognitive decline by targeting WMH may be age dependent.

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.

Pulse Pressure, Cognition, and White Matter Lesions: A Mediation Analysis

This study aimed to investigate the effects of pulse pressure (PP) on cognition and the role of white matter lesions (WMLs) in mediating this association. We enrolled 3,009 participants from the SPRINT-MIND study. Of those, 755 participants underwent brain magnetic resonance imaging. Cognitive tests were summarized in five cognition domains, including global cognition, executive function, attention, memory, and language. Multiple linear regression models were employed to analyze PP in association with cognition, and mediation analysis was applied to determine the role of WMLs in the association between PP and cognition. We found that PP was negatively linearly associated with global cognition (β = −0.048, P = 0.008), executive function (β = −0.014, P = 0.040), attention (β = −0.013, P = 0.035), memory (β = −0.021, P = 0.045), and language (β = −0.020, P = 0.001), respectively. Furthermore, PP was not significantly associated with brain component volume changes, except for WMLs (β = 0.029, P = 0.044). Additionally, mediation analysis showed that increased WML volume contributed to 10.8% of global cognition, 9.5% of executive function, 10.6% of memory, and 7.2% of language decline associated with PP. Exposure to higher PP levels was associated with poor cognitive performance, and WMLs partially moderated the influence of PP on cognition.

Microalbuminuria as a potential biomarker for Parkinson's disease severity: A hypothesis

Parkinson's disease (PD) is the second most common neurodegenerative condition characterized by motor and non-motor symptoms causing a great burden in patients' quality of life. PD has been associated with various metabolic factors such as diabetes, hypertension, and more recently chronic kidney disease where proteinuria has been associated with an increased risk. The presence of small amounts of albumin in urine, microalbuminuria, is a common biomarker for endothelial damage and a predictive factor for not only cardiovascular but also neurological dysfunction. Multiple studies have assessed potential biomarkers for PD progression with great heterogeneity, we hypothesize the use of microalbuminuria as a potential marker that correlates with PD severity and might represent a feasible and simple method of evaluating PD patients in clinical practice. Evidence supporting the present hypothesis comes from oxidative stress, insulin resistance, and endothelial dysfunction. Oxidative stress is a key element in PD pathogenesis; studies have shown lower antioxidant capacity as PD progresses. On the other side, insulin signaling plays an important role in neuronal growth and survival, with its resistance being associated with PD. Microalbuminuria has been associated with both processes; increased levels of oxidative stress markers and decreased insulin sensitivity, hence its screening in PD might reflect these common pathological mechanisms. Moreover, the low vitamin D levels observed in PD patients, which are correlated with endothelial dysfunction and disease severity, might contribute to microalbuminuria induction. More evidence on this vascular approach comes from white matter lesions (WML), observed in brain imaging, which have been significantly associated with motor and non-motor function in PD patients and are independently associated with microalbuminuria. In this manner, an oxidant and insulin resistant environment, along with low vitamin D levels in PD patients, which are associated with microalbuminuria, might contribute altogether to WML. As the latter are correlated with motor and non-motor function, microalbuminuria might thus give insight on PD status. Prospective cohort studies with an adequate sample size, follow-up, and a thorough battery of clinical tests for PD are needed to confirm this hypothesis.

C-reactive protein and risk of cognitive decline: The REGARDS study

Markers of systemic inflammation are associated with increased risk of cognitive impairment, but it is unclear if they are associated with a faster rate of cognitive decline and whether this relationship differs by race. Our objective was to examine the association of baseline C-reaction protein (CRP) with cognitive decline among a large racially diverse cohort of older adults. Participants included 21,782 adults aged 45 and older (36% were Black, Mean age at baseline 64) from the REasons for Geographic And Racial Differences in Stroke (REGARDS) study. CRP was measured at baseline and used as a continuous variable or a dichotomous grouping based on race-specific 90th percentile cutoffs. Cognitive measures of memory and verbal fluency were administered every 2 years for up to 12 years. Latent growth curve models evaluated the association of CRP on cognitive trajectories, adjusting for relevant demographic and health factors. We found that higher CRP was associated with worse memory (B = -.039, 95% CI [-.065,-.014]) and verbal fluency at baseline (B = -.195, 95% CI [-.219,-.170]), but not with rate of cognitive decline. After covariate adjustment, the association of CRP on memory was attenuated (B = -.005, 95% CI [-.031,-.021]). The association with verbal fluency at baseline, but not over time, remained (B = -.042, 95% CI [-.067,-.017]). Race did not modify the association between CRP and cognition. Findings suggest that levels of CRP at age 45+, are a marker of cognitive impairment but may not be suitable for risk prediction for cognitive decline.

Cognition, Brain Structure, and Brain Function in Individuals with Obesity and Related Disorders

PURPOSE OF REVIEW

Obesity is one of the most serious public health concerns. Excess adipose tissue, particularly with a centralized distribution, is associated with cognitive decline. Indeed, obesity has been associated with a number of adverse changes in brain function and structure that can be detected by neuroimaging techniques. These obesity-associated changes in the brain are associated with cognitive dysfunction.

RECENT FINDINGS

While the pathways by which excess adipose tissue affects brain function are not fully understood, available evidence points towards insulin resistance, inflammation, and vascular dysfunction, as possible mechanisms responsible for the observed relations between obesity and cognitive impairment. It appears that weight loss is related to better brain and cognitive outcomes and that cognitive impairment due to obesity may be reversible.

Prospectively Collected Cardiovascular Biomarkers and White Matter Hyperintensity Volume in Ischemic Stroke Patients

BACKGROUND

Few prospective cohort studies collect detailed information on stroke characteristics among individuals who experience ischemic stroke, including white matter hyperintensity volume, and thus cannot explore how prospectively collected biomarkers prior to the stroke influence white matter hyperintensity volume. We explored the association between a large panel of prospectively collected lipid and inflammatory biomarkers and white matter hyperintensity volume among participants in the Women's Health Study with incident ischemic stroke.

METHODS

Among Women's Health Study participants with first ischemic stroke who had baseline serum biomarkers and available magnetic resonance imaging, we measured white matter hyperintensity volume using a validated semi-automated method. Linear regression was used to explore the associations between biomarkers and log-transformed white matter hyperintensity volume.

RESULTS

After multivariate adjustment, a 1% increment in HbA1c% was associated with an increase in white matter hyperintensity volume (P value = .05). Evidence of a nonlinear association between high density lipoprotein cholesterol levels and ApoA1 levels with white matter hyperintensity volume was noted (P values for nonlinearity = .01 and .001, respectively). No other biomarkers were significantly associated with white matter hyperintensity volume.

CONCLUSIONS

Chronic hyperglycemia as evidenced by HbA1c levels measured years prior to stroke is associated with white matter hyperintensity volume at the time of stroke. Additional research is needed to explain why low levels of high density lipoprotein cholesterol levels and ApoA1 may be associated with similar white matter hyperintensity volume as high levels.

Obesity-related cognitive impairment: The role of endothelial dysfunction

Obesity is a global pandemic associated with macro- and microvascular endothelial dysfunction. Microvascular endothelial dysfunction has recently emerged as a significant risk factor for the development of cognitive impairment. In this review, we present evidence from clinical and preclinical studies supporting a role for obesity in cognitive impairment. Next, we discuss how obesity-related hyperinsulinemia/insulin resistance, systemic inflammation, and gut dysbiosis lead to cognitive impairment through induction of endothelial dysfunction and disruption of the blood brain barrier. Finally, we outline the potential clinical utility of dietary interventions, exercise, and bariatric surgery in circumventing the impacts of obesity on cognitive function.

Abdominal fatness and cerebral white matter hyperintensity

Although obesity has been proven as a risk factor of metabolic and cardiovascular diseases, there have been few studies addressing the association between obesity and cerebral white matter hyperintensity (WMH) volume with controversial findings. In this study, we evaluated the relationship between abdominal fat distribution and WMH volume in a neurologically healthy population. We performed an observational study in a consecutive series of subjects who were examined during voluntary health check-ups between January 2006 and December 2013. We directly measured both visceral adipose tissue (VAT) and subcutaneous adipose tissue (SAT) using abdominal computed tomography. The WMH volumes were also recorded quantitatively. A total of 2504 subjects were included in this study. In multivariate analysis, the relationship between SAT and WMH volume remained significant (β = -0.170, standard error [SE] = 0.065, P = .006) after adjusting for confounding factors. The protective effects of SAT on the WMH volume were more prominent in female participants (β = -0.295, SE = 0.138, P = .033) and in severely obese participants (β = -0.358, SE = 0.167, P = .033). Conclusively, we demonstrated a negative association between SAT and WMH volume in a healthy population.

Association between periodontitis and cognitive impairment: Analysis of national health and nutrition examination survey (NHANES) III

OBJECTIVES

Periodontitis has been hypothesized as being one of the most common potential risk factors for the development of dementia and cognitive impairment. In order to investigate the relationship between periodontitis and cognition impairment, the National Health and Nutrition Examination Survey (NHANES) database was analysed after adjusting for potential confounding factors, including age and other systemic co-morbidities.

MATERIALS AND METHODS

In total, 4,663 participants aged 20-59 years who had received full-mouth periodontal examination and undergone the cognitive functional test were enrolled. The grade of periodontal disease was categorized into severe, moderate, and mild. Cognitive function examinations, including the simple reaction time test (SRTT), symbol digit substitution test (SDST), and serial digit learning test (SDLT), were adopted for the evaluation of cognitive impairment.

RESULTS

The subjects with mild and moderate to severe periodontitis had higher SDLT and SDST scores, which indicated decreased cognitive function, compared with the healthy group. After adjusting for demographic factors, education, smoking, cardiovascular diseases, and laboratory data, periodontitis was significantly correlated with elevated SDST and SDLT scores (p values for trend = 0.014 and 0.038, respectively) by generalized linear regression models.

CONCLUSION

Our study highlighted that periodontal status was associated with cognitive impairment in a nationally representative sample of US adults.

Plasma Metabolites Associated with Brain MRI Measures of Neurodegeneration in Older Adults in the Atherosclerosis Risk in Communities⁻Neurocognitive Study (ARIC-NCS)

Background: Plasma metabolites are associated with cognitive and physical function in the elderly. Because cerebral small vessel disease (SVD) and neurodegeneration are common causes of cognitive and physical function decline, the primary objective of this study was to investigate the associations of six plasma metabolites (two plasma phosphatidylcholines [PCs]: PC aa C36:5 and PC aa 36:6 and four sphingomyelins [SMs]: SM C26:0, SM [OH] C22:1, SM [OH] C22:2, SM [OH] C24:1) with magnetic resonance imaging (MRI) features of cerebral SVD and neurodegeneration in older adults. Methods: This study included 238 older adults in the Atherosclerosis Risk in Communities study at the fifth exam. Multiple linear regression was used to assess the association of each metabolite (log-transformed) in separate models with MRI measures except lacunar infarcts, for which binary logistic regression was used. Results: Higher concentrations of plasma PC aa C36:5 had adverse associations with MRI features of cerebral SVD (odds ratio of 1.69 [95% confidence interval: 1.01, 2.83] with lacunar infarct, and beta of 0.16 log [cm3] [0.02, 0.30] with log [White Matter Hyperintensities (WMH) volume]) while higher concentrations of 3 plasma SM (OH)s were associated with higher total brain volume (beta of 12.0 cm3 [5.5, 18.6], 11.8 cm3 [5.0, 18.6], and 7.3 cm3 [1.2, 13.5] for SM [OH] C22:1, SM [OH] C22:2, and SM [OH] C24:1, respectively). Conclusions: This study identified associations between certain plasma metabolites and brain MRI measures of SVD and neurodegeneration in older adults, particularly higher SM (OH) concentrations with higher total brain volume.

Neurovascular and Cognitive Dysfunction in Hypertension

Hypertension has emerged as a leading cause of age-related cognitive impairment. Long known to be associated with dementia caused by vascular factors, hypertension has more recently been linked also to Alzheimer disease-the major cause of dementia in older people. Thus, although midlife hypertension is a risk factor for late-life dementia, hypertension may also promote the neurodegenerative pathology underlying Alzheimer disease. The mechanistic bases of these harmful effects remain to be established. Hypertension is well known to alter in the structure and function of cerebral blood vessels, but how these cerebrovascular effects lead to cognitive impairment and promote Alzheimer disease pathology is not well understood. Furthermore, critical questions also concern whether treatment of hypertension prevents cognitive impairment, the blood pressure threshold for treatment, and the antihypertensive agents to be used. Recent advances in neurovascular biology, epidemiology, brain imaging, and biomarker development have started to provide new insights into these critical issues. In this review, we will examine the progress made to date, and, after a critical evaluation of the evidence, we will highlight questions still outstanding and seek to provide a path forward for future studies.

Association Between Endothelial Function and Cognitive Performance in Patients With Coronary Artery Disease During Cardiac Rehabilitation

OBJECTIVE

Subtle cognitive deficits indicating early neural risk are common in the clinical presentation of coronary artery disease (CAD). Although deterioration may be mitigated by exercise, cognitive response to exercise is heterogeneous. Vasculopathy including endothelial dysfunction is a hallmark of CAD and may play an important role in impairing neural adaptation to exercise. This study aimed to assess peripheral measurements of endothelial function as predictors of cognitive performance in CAD participants undertaking cardiac rehabilitation (CR).

METHODS

CAD patients (N = 64) undergoing CR were recruited for this prospective observational study. Neuropsychological and endothelial function assessments were performed at baseline and after 3 months of CR. Z-scores for overall cognitive performance and specific cognitive domains (verbal and visuospatial memory, processing speed, and executive function) were calculated. Endothelial function was measured by the reactive hyperemia index (RHI) using peripheral arterial tonometry. Cross-sectional and longitudinal associations between RHI and overall cognition were assessed using linear regressions and mixed models, respectively. Domain-specific associations were also explored.

RESULTS

Although lower RHI was not associated with overall cognition at baseline (b = 0.26, p = .10), an increased RHI was significantly associated with an improvement in overall cognition (b = 0.55, p = .030) over 3 months. Lower RHI was associated with poorer verbal memory (β = 0.28, p = .027) at baseline and an increased RHI over 3 months was associated with an improvement in processing speed (b = 0.42, p = .033).

CONCLUSIONS

RHI may be a clinically useful predictor of cognitive change and might provide insight into the etiology of cognitive dysfunction in patients with CAD.

Exercise Improves Vascular Function, but does this Translate to the Brain?

The number of adults with Alzheimer’s disease (AD) or related dementia is expected to increase exponentially. Interventions aimed to reduce the risk and progression of AD and dementia are critical to the prevention and treatment of this devastating disease. Aging and cardiovascular disease risk factors are associated with reduced vascular function, which can have important clinical implications, including brain health. The age-associated increase in blood pressure and impairment in vascular function may be attenuated or even reversed through lifestyle behaviors. Greater volumes of habitual exercise and higher cardiorespiratory fitness are associated with beneficial effects on vascular health and cognition. Exercise and cardiorespiratory fitness may be most important during midlife, as physical activity and cardiorespiratory fitness during the middle-aged years are associated with future cognitive function. The extent to which exercise, and more specifically aerobic exercise, influences the cerebral circulation is not well established. In this review, we present our working hypothesis showing how cerebrovascular function may be a mediating factor underlying the association between exercise and cognition, as well as discuss recent studies evaluating the effect of exercise interventions on the cerebral circulation.

Microvascular Endothelial Function and Neurocognition Among Adults With Major Depressive Disorder

BACKGROUND

Cardiovascular risk factors (CVRFs) and endothelial dysfunction have been associated independently with poorer neurocognition in middle-aged adults, particularly on tests of frontal lobe function. However, to our knowledge, no studies have examined markers of microvascular dysfunction on neurocognition or the potential interaction between macro- and microvascular biomarkers on neurocognition in middle-aged and older adults with major depressive disorder (MDD).

METHODS

Participants included 202 adults with MDD who were not receiving mental health treatment. Microvascular endothelial function was assessed using a noninvasive marker of forearm reactive hyperemia velocity while macrovascular endothelial function was assessed using flow-mediated dilation (FMD) of the brachial artery. CVRFs were assessed using the Framingham Stroke Risk Profile and fasting lipid levels. A standardized neurocognitive assessment battery was used to assess three cognitive domains: executive function, working memory, and verbal memory.

RESULTS

Greater microvascular dysfunction was associated with poorer neurocognition across all three domains. Microvascular function continued to predict verbal memory performance after accounting for background factors and CVRFs. Macro- and microvascular function interacted to predict working memory performance (F = 4.51_{1, 178}, p = 0.035), with a similar nonsignificant association for executive function (F = 2.73_{1, 178}, p = 0.095), with moderate associations observed between microvascular function and neurocognition in the presence of preserved FMD (r₆₁ = 0.40, p = 0.001), but not when FMD was impaired (r₆₃ = -0.05, p = 0.675).

CONCLUSION

Greater microvascular dysfunction is associated with poorer neurocognition among middle-aged and older adults. This association was strongest in participants with preserved macrovascular function.

Sympathetic Overactivity Based on Heart-Rate Variability in Patients with Obstructive Sleep Apnea and Cerebral Small-Vessel Disease

Background and Purpose

Obstructive sleep apnea (OSA) is associated with cerebral white-matter changes (WMC), but the underlying mechanisms are not completely understood. Our aim was to identify the cardiovascular autonomic characteristics during sleep that are associated with cerebral WMC in OSA patients.

Methods

We recruited subjects from our sleep-center database who underwent both polysomnography and brain MRI within a 1-year period. Sixty patients who had OSA with WMC (OSA+WMC), 44 patients who had OSA without WMC (OSA−WMC), and 31 control subjects who had neither OSA nor WMC were analyzed. Linear and nonlinear indices of heart-rate variability (HRV) were analyzed in each group according to different sleep stages and also over the entire sleeping period.

Results

Among the nonlinear HRV indices, the Poincaré ratio (SD12) during the entire sleep period was significantly increased in the OSA+WMC group, even after age adjustment. Meanwhile, detrended fluctuation analysis 1 during non-rapid-eye-movement sleep tended to be lowest in the OSA+WMC group. These indices were altered regardless of the presence of hypertension or diabetes. In the subgroup analysis of middle-aged OSA patients, approximate entropy during rapid-eye-movement sleep was significantly lower in OSA+WMC patients than in OSA−WMC patients. Overall, the nonlinear HRV indices suggest that sympathetic activity was higher in the OSA+WMC group than in the OSA−WMC and control groups.

Conclusions

Our findings suggest that dysregulation of HRV, especially overactivation of sympathetic tone, could be a pathophysiologic mechanism underlying the development of WMC in OSA patients.

Arterial stiffness is associated with depression in middle-aged men - the Maastricht Study

BACKGROUND

Arterial stiffening may underlie the association between depression and cardiovascular disease (CVD), but reported data are inconsistent. We investigated the associations between aortic stiffness and major depressive disorder (MDD) and depressive symptoms, and whether these differed by sex and age.

METHODS

We measured carotid to femoral pulse wave velocity (cfPWV) using applanation tonometry, and we assessed depression using the Mini-International Neuropsychiatric Interview (MINI) and the Patient Health Questionnaire-9 (PHQ-9) in a cohort of participants from The Maastricht Study. Logistic and negative binominal models were adjusted for age, type 2 diabetes mellitus (T2DM), mean arterial pressure (MAP) and CVD risk factors.

RESULTS

We included 2757 participants in our analyses (48.8% men, mean age 59.8 ± 8.1 yr, 27% T2DM). We found that cfPWV was associated with MDD in men (fully adjusted odds ratio [OR] 2.36, 95% confidence interval [CI] 1.45-3.84), but not in women (OR 1.57, 95% CI 0.93-2.66), aged 60 years or younger. The ORs were not significant in individuals older than 60 years (men: OR 1.03, 95% CI 0.63-1.68; women: OR 0.64, 95% CI 0.32-1.31). Similarly, cfPWV was associated with a higher PHQ-9 score in men (rate ratio 1.28, 95% CI 1.09-1.52), but not in women (rate ratio 1.11, 95% CI 0.99-1.23), aged 60 years or younger. Associations were not significant in individuals older than 60 years (men: rate ratio 0.96, 95% CI 0.84-1.08; women: rate ratio 1.00, 95% CI 0.90-1.12).

LIMITATIONS

We cannot rule out reversed causation in this cross-sectional study.

CONCLUSION

Greater aortic stiffness is associated with MDD and depressive symptoms among middle-aged men and to a lesser extent in women, whereas this association was not observed in old age.

Arterial stiffness is associated with depression in middle-aged men - the Maastricht Study

BACKGROUND

Arterial stiffening may underlie the association between depression and cardiovascular disease (CVD), but reported data are inconsistent. We investigated the associations between aortic stiffness and major depressive disorder (MDD) and depressive symptoms, and whether these differed by sex and age.

METHODS

We measured carotid to femoral pulse wave velocity (cfPWV) using applanation tonometry, and we assessed depression using the Mini-International Neuropsychiatric Interview (MINI) and the Patient Health Questionnaire-9 (PHQ-9) in a cohort of participants from The Maastricht Study. Logistic and negative binominal models were adjusted for age, type 2 diabetes mellitus (T2DM), mean arterial pressure (MAP) and CVD risk factors.

RESULTS

We included 2757 participants in our analyses (48.8% men, mean age 59.8 ± 8.1 yr, 27% T2DM). We found that cfPWV was associated with MDD in men (fully adjusted odds ratio [OR] 2.36, 95% confidence interval [CI] 1.45-3.84), but not in women (OR 1.57, 95% CI 0.93-2.66), aged 60 years or younger. The ORs were not significant in individuals older than 60 years (men: OR 1.03, 95% CI 0.63-1.68; women: OR 0.64, 95% CI 0.32-1.31). Similarly, cfPWV was associated with a higher PHQ-9 score in men (rate ratio 1.28, 95% CI 1.09-1.52), but not in women (rate ratio 1.11, 95% CI 0.99-1.23), aged 60 years or younger. Associations were not significant in individuals older than 60 years (men: rate ratio 0.96, 95% CI 0.84-1.08; women: rate ratio 1.00, 95% CI 0.90-1.12).

LIMITATIONS

We cannot rule out reversed causation in this cross-sectional study.

CONCLUSION

Greater aortic stiffness is associated with MDD and depressive symptoms among middle-aged men and to a lesser extent in women, whereas this association was not observed in old age.

Low-grade albuminuria is associated with poor memory performance in the nondemented Chinese elderly with type 2 diabetes

Recent studies have correlated cognitive function with albuminuria. We investigated the association between low-grade albuminuria and cognitive performance in nondemented elderly with type 2 diabetes in Fuzhou, China. Between January, 2013 and December, 2014, a retrospective study was performed in 815 patients with type 2 diabetes (398 female and 417 male patients), ages ≥60 years, with normal urinary albumin to creatinine ratios (UACR <30 mg/g). Patients were stratified into tertiles based on UACR levels (lowest tertile, UACR <5.8 mg/g; highest tertile, UACR ≥18.1 mg/g). Cognitive function was measured using the Mini Mental State Examination. UACR tertiles correlated directly (p < 0.05) with age, duration of diabetes, systolic blood pressure (SBP), and pulse wave velocity (PWV). Patients in the second and highest tertiles performed significantly worse on memory and language than those in the lowest UACR tertile (p < 0.05). The association between UACR and memory loss was stronger in patients younger than 70 years of age and in those with a history of diabetes for less than 10 years. Low-grade albuminuria is associated with poor memory performance, especially in the youngest old (60-69 years) and in those with shorter duration of diabetes (< 10 years). Type 2 diabetics with urinary albumin excretion in the upper normal range were also at risk for declining memory performance.

Understanding a role for hypoxia in lesion formation and location in the deep and periventricular white matter in small vessel disease and multiple sclerosis

The deep and periventricular white matter is preferentially affected in several neurological disorders, including cerebral small vessel disease (SVD) and multiple sclerosis (MS), suggesting that common pathogenic mechanisms may be involved in this injury. Here we consider the potential pathogenic role of tissue hypoxia in lesion development, arising partly from the vascular anatomy of the affected white matter. Specifically, these regions are supplied by a sparse vasculature fed by long, narrow end arteries/arterioles that are vulnerable to oxygen desaturation if perfusion is reduced (as in SVD, MS and diabetes) or if the surrounding tissue is hypoxic (as in MS, at least). The oxygen crisis is exacerbated by a local preponderance of veins, as these can become highly desaturated 'sinks' for oxygen that deplete it from surrounding tissues. Additional haemodynamic deficiencies, including sluggish flow and impaired vasomotor reactivity and vessel compliance, further exacerbate oxygen insufficiency. The cells most vulnerable to hypoxic damage, including oligodendrocytes, die first, resulting in demyelination. Indeed, in preclinical models, demyelination is prevented if adequate oxygenation is maintained by raising inspired oxygen concentrations. In agreement with this interpretation, there is a predilection of lesions for the anterior and occipital horns of the lateral ventricles, namely regions located at arterial watersheds, or border zones, known to be especially susceptible to hypoperfusion and hypoxia. Finally, mitochondrial dysfunction due to genetic causes, as occurs in leucodystrophies or due to free radical damage, as occurs in MS, will compound any energy insufficiency resulting from hypoxia. Viewing lesion formation from the standpoint of tissue oxygenation not only reveals that lesion distribution is partly predictable, but may also inform new therapeutic strategies.

Cerebral white matter hyperintensity is associated with intracranial atherosclerosis in a healthy population

BACKGROUND AND AIMS

Cerebral white matter hyperintensity (WMH) is commonly found in ischemic stroke patients, especially when accompanied by intracranial atherosclerosis (ICAS). However, the relationship between WMH and ICAS in a healthy population has not been evaluated.

METHODS

A total of 3159 healthy subjects who underwent health checkups, including brain magnetic resonance imaging and angiography, were enrolled. ICAS was defined as an occlusion or more than 50% stenosis of intracranial vessels on magnetic resonance angiography. Volumes of WMH were quantitatively rated.

RESULTS

Eighty-two (2.6%) subjects had ICAS. The mean age of the cohort was 56 years, and the median volume of WMH was 1.02 [0.20-2.60] mL. In a multivariate analysis, ICAS [β = 0.331, 95% confidence interval (CI) = 0.086 to 0.576, p = 0.008] was significantly associated with WMH volumes after adjusting confounders. Age (β = 0.046, 95% CI = 0.042 to 0.050, p < 0.001), hypertension (β = 0.113, 95% CI = 0.017 to 0.210, p = 0.021), and diabetes (β = 0.154, 95% CI = 0.043 to 0.265, p = 0.006) were also significant, independently of ICAS. The ICAS (+) group had more frequent vascular risk factors including hypertension, diabetes, and statin use, than the ICAS (-) group, and these tendencies increased when WMH was accompanied by ICAS.

CONCLUSIONS

ICAS is associated with larger WMH volume in a healthy population. Close observation of this group and strict control of vascular risk factors are needed.

Analysis of risk factors in patients with leukoaraiosis

To investigate the risk factors for leukoaraiosis (LA) and the correlation between risk factors and LA.The study comprised 92 patients with diagnoses of LA (LA group) and 56 non-LA individuals (control group). Data were collected for the following: age, gender, fasting blood glucose, total cholesterol, triglyceride, high- and low-density lipoprotein cholesterol, uric acid, creatinine, and histories of smoking, hypertension, and diabetes. Levels of serum asymmetric dimethylarginine (ADMA) were detected by enzyme-linked immunosorbent assay.Univariate analysis showed statistical significance between the 2 groups in age, histories of hypertension and smoking, uric acid, creatinine, and levels of serum ADMA (P < 0.05). Binary logistic analysis showed that age (P < 0.0001), hypertension (P = 0.0101), and serum ADMA (P = 0.0206) were related to LA. Pearson correlation analysis showed that levels of serum ADMA correlated with uric acid (r = 0.184, P = 0.025) and creatinine (r = 0.169, P = 0.04).Age, hypertension, and levels of serum ADMA were independent risk factors for LA. Serum ADMA levels may be related to uric acid and creatinine.

Impact of Hypertension on Cognitive Function: A Scientific Statement From the American Heart Association

BACKGROUND

Age-related dementia, most commonly caused by Alzheimer disease or cerebrovascular factors (vascular dementia), is a major public health threat. Chronic arterial hypertension is a well-established risk factor for both types of dementia, but the link between hypertension and its treatment and cognition remains poorly understood. In this scientific statement, a multidisciplinary team of experts examines the impact of hypertension on cognition to assess the state of the knowledge, to identify gaps, and to provide future directions.

METHODS

Authors with relevant expertise were selected to contribute to this statement in accordance with the American Heart Association conflict-of-interest management policy. Panel members were assigned topics relevant to their areas of expertise, reviewed the literature, and summarized the available data.

RESULTS

Hypertension disrupts the structure and function of cerebral blood vessels, leads to ischemic damage of white matter regions critical for cognitive function, and may promote Alzheimer pathology. There is strong evidence of a deleterious influence of midlife hypertension on late-life cognitive function, but the cognitive impact of late-life hypertension is less clear. Observational studies demonstrated a cumulative effect of hypertension on cerebrovascular damage, but evidence from clinical trials that antihypertensive treatment improves cognition is not conclusive.

CONCLUSIONS

After carefully reviewing the literature, the group concluded that there were insufficient data to make evidence-based recommendations. However, judicious treatment of hypertension, taking into account goals of care and individual characteristics (eg, age and comorbidities), seems justified to safeguard vascular health and, as a consequence, brain health.

Diabetes mellitus and white matter hyperintensity

White matter hyperintensity (WMH) is a brain lesion detected as a high-intensity area in magnetic resonance imaging T2 and fluid-attenuated inversion recovery images, and it has been suggested that WMH reflects damage to small vessels in periventricular and subcortical areas. Although WMH has been linked to the incidence of stroke, more recently it has been clarified that WMH is also associated with progression of cognitive decline and functional disability, which are components of so-called geriatric syndrome. In addition to hypertension, which is the classical risk factor for WMH, evidence has been accumulating to suggest that diabetes mellitus could also be associated with WMH progression, and some studies have shown that WMH severity is correlated with cognitive decline in patients with diabetes. The factors that accelerate WMH formation in elderly patients with diabetes remain poorly defined. It is considered that insulin resistance is an exacerbating factor, but the effects of hypertension, dyslipidemia or other vascular risk factors have yet be clarified, and further studies are required.

Relationships among psychoneurological symptoms and levels of C-reactive protein over 2 years in women with early-stage breast cancer

PURPOSE

The aim of the present study was to explore clusters of psychoneurological symptoms and inflammation (levels of C-reactive protein) over time in a cohort of women with early-stage breast cancer. Specifically, we examined the relationships among affective symptoms (depression, anxiety, fatigue, sleep disturbances, pain, and perceived stress), domains of cognitive performance, and levels of peripheral C-reactive over a period of 2 years.

METHODS

This was a prospective, longitudinal study of 77 women diagnosed with early-stage breast cancer. Data collection, including symptom questionnaires, performance-based cognitive testing, and blood draws, took place at 5 time points: prior to initiating adjuvant chemotherapy, prior to the fourth chemotherapy treatment, and at 6, 12, and 24 months after the initiation of chemotherapy.

RESULTS

Exploratory factor analysis with varimax orthogonal rotation was used to examine the covariance among symptoms at each visit. Using the factor scores and weighted sums, three clusters were identified: global cognition, affective symptoms, and cognitive efficiency. Peripheral levels of C-reactive protein were inversely correlated with the cognitive efficiency factor across time.

CONCLUSIONS

The findings suggest that objectively measured domains of cognitive function occur independently of other affective symptoms that are commonly reported by women with breast cancer in long-term survivorship. The cognitive efficiency symptom cluster may be amenable to interventions targeted to biological influences that reduce levels of C-reactive protein.

Vascular Function in Alzheimer's Disease and Vascular Dementia

We investigated vascular functioning in patients with a clinical and radiological diagnosis of either Alzheimer's disease (AD) or vascular dementia (VaD) and examined a possible relationship between vascular function and cognitive status. Twenty-seven patients with AD, 23 patients with VaD, and 26 healthy control patients underwent measurements of flow-mediated dilation (FMD), ankle-brachial index (ABI), cardioankle vascular index (CAVI), and intima-media thickness (IMT). The FMD was significantly lower in patients with AD or VaD compared to controls. There were no significant differences in ABI, CAVI, or IMT among the 3 groups. A significant correlation was found between Mini-Mental State Examination (MMSE) scores and FMD. Furthermore, a multiple regression analysis revealed that FMD was significantly predicted by MMSE scores. These results suggest that endothelial involvement plays a role in AD pathogenesis, and FMD may be more sensitive than other surrogate methods (ABI, CAVI, and IMT) for detecting early-stage atherosclerosis and/or cognitive decline.

Higher Visit-to-Visit Low-Density Lipoprotein Cholesterol Variability Is Associated With Lower Cognitive Performance, Lower Cerebral Blood Flow, and Greater White Matter Hyperintensity Load in Older Subjects

Background:

Recently, it was shown that intraindividual variation in low-density lipoprotein cholesterol (LDL-C) predicts both cerebrovascular and cardiovascular events. We aimed to examine whether this extends to cognitive function and examined possible pathways using a magnetic resonance imaging substudy.

Methods:

We investigated the association between LDL-C variability and 4 cognitive domains at month 30 in 4428 participants of PROSPER (PROspective Study of Pravastatin in the Elderly at Risk). Additionally, we assessed the association of LDL-C variability with neuroimaging outcomes in a subset of 535 participants. LDL-C variability was defined as the intraindividual standard deviation over 4 postbaseline LDL-C measurements, and all analyses were adjusted for mean LDL-C levels and cardiovascular risk factors.

Results:

Higher LDL-C variability was associated with lower cognitive function in both the placebo and pravastatin treatment arms. Associations were present for selective attention ( P =0.017 and P =0.11, respectively), processing speed ( P =0.20 and P =0.029), and memory (immediate recall, P =0.002 and P =0.006; delayed recall, P =0.001 and P ≤0.001). Furthermore, higher LDL-C variability was associated with lower cerebral blood flow in both trial arms ( P =0.031 and P =0.050) and with greater white matter hyperintensity load in the pravastatin arm ( P =0.046). No evidence was found for interaction between LDL-C variability and pravastatin treatment for both cognitive and magnetic resonance imaging outcomes.

Conclusions:

We found that higher visit-to-visit variability in LDL-C, independently of mean LDL-C levels and statin treatment, is associated with lower cognitive performance, lower cerebral blood flow, and greater white matter hyperintensity load.

Serum antioxidant levels associated with subcortical ischemic vascular disease

OBJECTIVE

We aimed to examine changes in serum bilirubin and uric acid (ua) levels in subcortical ischemic vascular disease (Sivd). in addition, we investigated if altered serum bilirubin and ua levels correlate with the subtypes of Sivd as well as the severity of leukoaraiosis (la).

METHODS

this cross-sectional study included 1098 consecutive patients with slight symptoms, such as dizziness, vertigo etc. according to magnetic resonance imaging (Mri) appearances, they were divided into either Sivd group or controls (Cn), and the Sivd group was further grouped in lacunar infarction (li) and la subtypes, as well as different grades. Serum bilirubin and ua levels were determined by the vanadate oxidase method and enzymatic method respectively, after at least an eight hour overnight fasting, in all subjects.

RESULTS

the bilirubin level was obviously lower while the ua level was significantly higher in the Sivd group when compared with the controls. Moreover, the la subgroup presented more significant changes in bilirubin and ua when compared to the li subgroup in both males and females. the correlation was positive between the ua levels and the la severity (r=0.134, p=0.006). Multivariate regression analysis revealed that the odds ratio (95% Ci) for Sivd in the lowest tertile of total bilirubin (tbil<9.58 μmol/l) and highest tertile of ua (ua>339 μmol/l) were 2.702(1.936-3.770) and 2.135(1.521-2.996) respectively after adjusting for confounding variables.

CONCLUSION

Serum bilirubin levels were lower, whereas ua levels were higher in Sivd patients when compared with controls in both males and females, especially in la patients. Moreover, serum ua levels positively correlated to la severity.

Red Blood Cell Distribution Width Is Associated with Severity of Leukoaraiosis

Red blood cell distribution width (RDW) is one of the routine hematologic parameters reported in the complete blood count test, which has been recognized as strong prognostic marker for various medical conditions, especially cardiovascular disease. We evaluated that RDW was also associated with the leukoaraiosis; common radiological finding of brain and that has been strongly associated with risk of stroke and dementia. In the present study, we included 1006 non-stroke individuals who underwent brain MRI and routine complete blood count test including RDW. Fazekas scale was used to measure the severity of leukoaraiosis based on fluid-attenuated inversion recovery image, and the severity was dichotomized to mild-degree (Fazekas scale: 0–1) and severe-degree leukoaraiosis (Fazekas scale: 2–3). Univariate and multivariate logistic regression models were constructed to evaluate independent risk factor for severe-degree of leukoaraiosis. Mean age of 1006 subjects was 64.34 ± 9.11 year, and mean of RDW was 12.97 ± 0.86%. The severe-degree of leukoaraiosis (Fazekas scale ≥ 2) was found in 28.83%. In the multivariate logistic regression, 4^th quartile of RDW (> 13.3%) were significantly associated with the presence of severe-degree of leukoaraiosis (adjusted odds ratio, 1.87; 95% confidence interval, 1.20–2.92) compared to the 1^st quartile of RDW (< 12.5%). The significance was not changed after adjustments for hemoglobin and other hematologic indices. These findings suggest that RDW is independently associated with severity of leukoaraiosis.

Individual variability of cerebral autoregulation, posterior cerebral circulation and white matter hyperintensity

KEY POINTS

Cerebral autoregulation (CA) is a key mechanism to protect brain perfusion in the face of changes in arterial blood pressure, but little is known about individual variability of CA and its relationship to the presence of brain white matter hyperintensity (WMH) in older adults, a type of white matter lesion related to cerebral small vessel disease (SVD). This study demonstrated the presence of large individual variability of CA in healthy older adults during vasoactive drug-induced changes in arterial pressure assessed at the internal carotid and vertebral arteries. We also observed, unexpectedly, that it was the 'over-' rather than the 'less-reactive' CA measured at the vertebral artery that was associated with WMH severity. These findings challenge the traditional concept of CA and suggest that the presence of cerebral SVD, manifested as WMH, is associated with posterior brain hypoperfusion during acute increase in arterial pressure.

ABSTRACT

This study measured the individual variability of static cerebral autoregulation (CA) and determined its associations with brain white matter hyperintensity (WMH) in older adults. Twenty-seven healthy older adults (13 females, 66 ± 6 years) underwent assessment of CA during steady-state changes in mean arterial pressure (MAP) induced by intravenous infusion of sodium nitroprusside (SNP) and phenylephrine. Cerebral blood flow (CBF) was measured using colour-coded duplex ultrasonography at the internal carotid (ICA) and vertebral arteries (VA). CA was quantified by a linear regression slope (CA slope) between percentage changes in cerebrovascular resistance (CVR = MAP/CBF) and MAP relative to baseline values. Periventricular and deep WMH volumes were measured with T2-weighted magnetic resonance imaging. MAP was reduced by -11 ± 7% during SNP, and increased by 21 ± 8% during phenylephrine infusion. CA demonstrated large individual variability with the CA slopes ranging from 0.37 to 2.20 at the ICA and from 0.17 to 3.18 at the VA; no differences in CA were found between the ICA and VA. CA slopes measured at the VA had positive correlations with the total and periventricular WMH volume (r = 0.55 and 0.59, P < 0.01). Collectively, these findings demonstrated the presence of large individual variability of CA in older adults, and that, when measured in the posterior cerebral circulation, it is the higher rather than lower CA reactivity that is associated with WMH severity.

Flow-Mediated Dilation and Neurocognition: Systematic Review and Future Directions

BACKGROUND

Previous literature indicates that flow-mediated dilation (FMD) is associated with impaired cognition among patients with stroke. The relationship between FMD and cognition in individuals without cerebrovascular disease has yet to be systematically reviewed.

METHODS

The literature was searched using MEDLINE. Exclusion criteria were as follows: focus on neurological disease (e.g., stroke), animal studies, no quantitative measure of endothelial function or cognition, newborn studies, articles with no original data, and articles that are irrelevant to the topic of interest. Neurocognitive tests were categorized in the following domains: executive function, memory (general, working, episodic/semantic, verbal, visual), global cognitive function, information processing speed, language, psychomotor speed, and visual-spatial ability.

RESULTS

The search yielded 700 articles, of which 10 articles, consisting of 2791 participants, met the criteria for inclusion. Most studies conclude that impaired FMD is associated with poorer neuropsychological functioning, particularly in executive functioning (effect sizes: r = 0.07-0.58) and working memory tasks (effect sizes: r = 0.19-0.39). No association was found between other subdomains of memory and FMD. Visual spatial tasks, information processing speed, language tasks, and global cognition were not associated with FMD overall; however fewer studies examined these domains.

CONCLUSIONS

Even in the absence of cerebrovascular disease, there are links between cognition, particularly executive tasks, and vascular function. Public health implications include the potential value of examining FMD as a predictor of cognitive decline, as well as the potential value of improving cognition through pharmacological and behavioral interventions that improve vascular function. Future studies incorporating neuroimaging measures of cerebral blood flow are warranted.