Frequency of subclinical heart disease in elderly persons with dementia

Regional variability of the impact of cardiometabolic diseases on incident dementia in United States Medicare beneficiaries

INTRODUCTION

Understanding the impact of cardiometabolic diseases (CMDs) on dementia risk can inform primary preventative measures.

METHODS

We leveraged a nationwide, population-based Medicare dataset of 20,789,037 beneficiaries (756,321 with incident dementia and 20,032,716 controls) from 2017 to compute the individual and combined population attributable fractions (PAFs) of dementia attributed to eight CMDs, adjusted for age, sex, and race. We mapped PAFs at the county level to investigate the geospatial patterns of CMD burden on dementia across the United States.

RESULTS

The nationwide combined weighted PAF for the eight CMDs was 37% overall, with hypertension (9.6%), ischemic heart disease (6.7%), and chronic heart failure (5.7%) associated with the greatest attributable fractions of dementia cases. The greatest fraction of county-level dementia cases attributed to CMDs were in the Southeastern United States.

DISCUSSION

A substantial proportion of incident dementia cases in the United States can be attributed to CMDs, especially in the Southeastern United States.

HIGHLIGHTS

Investigated the combined effect of cardiometabolic diseases (CMDs) on dementia. Used novel geospatial techniques to map the burden of dementia attributed to CMDs. If eight CMDs are mitigated, 37% of incident dementia cases could be eliminated. Identified regions of the United States with high CMD burden on dementia.

Dementia is associated with worse procedural outcomes after mitral valve transcatheter edge-to-edge repair

BACKGROUND

Patients with dementia are at increased risk for adverse events following valvular surgery. Outcomes after mitral transcatheter edge-to-edge repair (TEER) for mitral regurgitation in this vulnerable population are not well understood.

METHODS

We queried the National Inpatient Sample database for all hospitalizations for mitral TEER between 2016 and 2019. Patients with a validated diagnosis code for dementia were identified by ICD-10 codes and compared to a matched cohort of non-dementia patients using multivariable regression analysis. The primary outcome was in-hospital mortality. Secondary outcomes were hospital length of stay, discharge to nursing facility, total hospital charges, and in-hospital adverse events.

RESULTS

24,550 hospitalizations for mitral TEER were identified, including 880 patients (3.6 %) with dementia. Dementia was associated with higher in-hospital mortality (OR 4.31, 95 % CI 2.65 to 6.99, p < 0.001), prolonged length of hospital stay (OR 1.33, 95 % CI 1.12 to 1.57, p 0.001), higher discharge rate to nursing facility (OR 2.71, 95 % CI 2.13-3.44, p < 0.001), and higher rate of in-hospital adverse events including delirium (OR 5.88, 95 % CI 4.06 to 8.52, p < 0.001) and acute stroke (OR 8.87, 95 % CI 5.01 to 15.70, p < 0.001).

CONCLUSIONS

Dementia is associated with worse post-procedural outcomes after mitral TEER. Further investigation is needed to elucidate mechanisms of poor clinical outcomes and guide shared decision-making in this vulnerable population.

Cardiac Dysfunction in a Mouse Vascular Dementia Model of Bilateral Common Carotid Artery Stenosis

Background: Cardiac function is associated with cognitive function. Previously, we found that stroke and traumatic brain injury evoke cardiac dysfunction in mice. In this study, we investigate whether bilateral common carotid artery stenosis (BCAS), a model that induces vascular dementia (VaD) in mice, induces cardiac dysfunction. Methods: Late-adult (6-8 months) C57BL/6J mice were subjected to sham surgery (n = 6) or BCAS (n = 8). BCAS was performed by applying microcoils (0.16 mm internal diameter) around both common carotid arteries. Cerebral blood flow and cognitive function tests were performed 21-28 days post-BCAS. Echocardiography was conducted in conscious mice 29 days after BCAS. Mice were sacrificed 30 days after BCAS. Heart tissues were isolated for immunohistochemical evaluation and real-time PCR assay. Results: Compared to sham mice, BCAS in mice significantly induced cerebral hypoperfusion and cognitive dysfunction, increased cardiac hypertrophy, as indicated by the increased heart weight and the ratio of heart weight/body weight, and induced cardiac dysfunction and left ventricular (LV) enlargement, indicated by a decreased LV ejection fraction (LVEF) and LV fractional shortening (LVFS), increased LV dimension (LVD), and increased LV mass. Cognitive deficits significantly correlated with cardiac deficits. BCAS mice also exhibited significantly increased cardiac fibrosis, increased oxidative stress, as indicated by 4-hydroxynonenal and NADPH oxidase-2, increased leukocyte and macrophage infiltration into the heart, and increased cardiac interleukin-6 and thrombin gene expression. Conclusions: BCAS in mice without primary cardiac disease provokes cardiac dysfunction, which, in part, may be mediated by increased inflammation and oxidative stress.

The Heart of the Alzheimer's: A Mindful View of Heart Disease

Purpose of Review: This review summarizes the current evidence for the involvement of proteotoxicity and protein quality control systems defects in diseases of the central nervous and cardiovascular systems. Specifically, it presents the commonalities between the pathophysiology of protein misfolding diseases in the heart and the brain. Recent Findings: The involvement of protein homeostasis dysfunction has been for long time investigated and accepted as one of the leading pathophysiological causes of neurodegenerative diseases. In cardiovascular diseases instead the mechanistic focus had been on the primary role of Ca2+ dishomeostasis, myofilament dysfunction as well as extracellular fibrosis, whereas no attention was given to misfolding of proteins as a pathogenetic mechanism. Instead, in the recent years, several contributions have shown protein aggregates in failing hearts similar to the ones found in the brain and increasing evidence have highlighted the crucial importance that proteotoxicity exerts via pre-amyloidogenic species in cardiovascular diseases as well as the prominent role of the cellular response to misfolded protein accumulation. As a result, proteotoxicity, unfolding protein response (UPR), and ubiquitin-proteasome system (UPS) have recently been investigated as potential key pathogenic pathways and therapeutic targets for heart disease. Summary: Overall, the current knowledge summarized in this review describes how the misfolding process in the brain parallels in the heart. Understanding the folding and unfolding mechanisms involved early through studies in the heart will provide new knowledge for neurodegenerative proteinopathies and may prepare the stage for targeted and personalized interventions.

Integrative Multi-Omics Analysis in Calcific Aortic Valve Disease Reveals a Link to the Formation of Amyloid-Like Deposits

Calcific aortic valve disease (CAVD) is the most prevalent valvular heart disease in the developed world, yet no pharmacological therapy exists. Here, we hypothesize that the integration of multiple omic data represents an approach towards unveiling novel molecular networks in CAVD. Databases were searched for CAVD omic studies. Differentially expressed molecules from calcified and control samples were retrieved, identifying 32 micro RNAs (miRNA), 596 mRNAs and 80 proteins. Over-representation pathway analysis revealed platelet degranulation and complement/coagulation cascade as dysregulated pathways. Multi-omics integration of overlapping proteome/transcriptome molecules, with the miRNAs, identified a CAVD protein–protein interaction network containing seven seed genes (apolipoprotein A1 (APOA1), hemoglobin subunit β (HBB), transferrin (TF), α-2-macroglobulin (A2M), transforming growth factor β-induced protein (TGFBI), serpin family A member 1 (SERPINA1), lipopolysaccharide binding protein (LBP), inter-α-trypsin inhibitor heavy chain 3 (ITIH3) and immunoglobulin κ constant (IGKC)), four input miRNAs (miR-335-5p, miR-3663-3p, miR-21-5p, miR-93-5p) and two connector genes (amyloid beta precursor protein (APP) and transthyretin (TTR)). In a metabolite–gene–disease network, Alzheimer’s disease exhibited the highest degree of betweenness. To further strengthen the associations based on the multi-omics approach, we validated the presence of APP and TTR in calcified valves from CAVD patients by immunohistochemistry. Our study suggests a novel molecular CAVD network potentially linked to the formation of amyloid-like structures. Further investigations on the associated mechanisms and therapeutic potential of targeting amyloid-like deposits in CAVD may offer significant health benefits.

Heart and Brain: Complex Relationships for Left Ventricular Dysfunction

PURPOSE OF REVIEW

This review summarizes the evidence for the established vascular/hypoperfusion model and explores the new hypothesis that configures the heart/brain axis as an organ system where similar pathogenic mechanisms exploit physiological and pathological changes.

RECENT FINDINGS

Although associated by common risk factors, similar epidemiological stratification and common triggers (including inflammation, oxidative stress, and hypoxia), heart failure and Alzheimer's disease have been, for long time, viewed as pathogenically separate illnesses. The silos began to be broken down with the awareness that vascular dysfunction, and loss of cardiac perfusion pump power, trigger biochemical changes, contributing to the typical hallmark of Alzheimer's disease (AD)-the accumulation of Aβ plaques and hyperphosphorylated Tau tangles. Compromised blood flow to the brain becomes the paradigm for the "heart-to-head" connection. Compelling evidence of common genetic variants, biochemical characteristics, and the accumulation of Aβ outside the brain suggests a common pathogenesis for heart failure (HF) and AD. These new findings represent just the beginning of the understanding the complex connection between AD and HF requiring further studies and interdisciplinary approaches. Altogether, the current evidence briefly summarized in this review, highlight a closer and complex relationship between heart failure and Alzheimer's that goes beyond the vascular/perfusion hypothesis. Genetic and biochemical evidence begin to suggest common pathogenic mechanisms between the two diseases involving a systemic defect in the folding of protein or a seeding at distance of the misfolded proteins from one organ to the other.

Beneficial effects of resveratrol and exercise training on cardiac and aortic function and structure in the 3xTg mouse model of Alzheimer's disease

Background: Studies have indicated an association between Alzheimer’s disease (AD) and increased risk of developing cardiovascular complications. Lifestyle modifiable factors, such as exercise and diet, are known to prevent cardio-cerebral disease. Recent studies demonstrate that hearts from early onset triple-transgenic AD mice exhibit pathologies, but it is not clear whether cardiovascular function is altered in this model. Methods: In this study, we measured in vivo cardiovascular function in 7-month-old male 3xTg mice and age-matched wild-type (WT) mice using high-frequency high-resolution ultrasound imaging. Results: Our findings indicated that aortic root measurements and interventricular septal dimensions were similar in 3xTg and wild-type mice. Systolic function, expressed as ejection fraction and fractional shortening, were decreased in 3xTg mice. Late (A) ventricular filling velocities, the early/atrial (E/A) ratio, and mitral valve deceleration time, all indices of diastolic function, were increased in 3xTg mice compared to WT mice. Treadmill exercise training and resveratrol supplementation in the diet for 5 months improved ejection fraction, fractional shortening, and restored diastolic deceleration times. Pulse wave velocity was ~33% higher in 3xTg, and accompanied by a significant increase in elastin fiber fragmentation within the aortic wall, which was associated with decrease in elastin content and fiber length. Aortic wall and adventitia thickness were increased in 3xTg mice compared to the WT group. Exercise training and resveratrol supplementation, or both, improved overall aortic morphology with no change in pulse wave velocity. Conclusion: Taken together, the results indicate that the aberrations in cardiac function and aortic elastin morphology observed in the 3xTg mouse model of AD can be prevented with exercise training and treatment with resveratrol. The benefits of regular exercise training and resveratrol supplementation of heart and aortic structure in the 3xTg mouse support the value of healthy lifestyle factors on cardiovascular health.

Qi Fu Yin-a Ming Dynasty Prescription for the Treatment of Dementia

The Traditional Chinese Medicine (TCM) theory that “kidneys give rise to marrow, and the brain is the sea of marrow” has been a guide for the clinical application of kidney, qi and blood tonics for prevention and treatment of dementia and improvement in memory. As low resistance end-organs, both the brain and the kidneys are subjected to blood flow of high volumes throughout the cardiac cycle. Alzheimer’s disease and vascular dementia are two common causes of dementia, and it is increasingly recognized that many older adults with dementia have both AD and vascular pathologies. The underlying molecular mechanisms are incompletely understood, but may involve atherosclerosis, vascular dysfunction, hypertension, type 2 diabetes, history of cardiac disease and possibly, kidney dysfuntion, leading to reduced erythropoietin production, anemia, brain energy deficit and slow excitotoxicity. During the Ming Dynasty, Zhang Jing-Yue used Qi Fu Yin (seven blessings decoction), comprising Panax ginseng, Rehmannia glutinosa, Angelica polymorpha, Atractylodes macrocephala, Glycyrrhiza uralensis, Ziziphus jujube, and Polygala tenuifolia to boost qi and blood circulation, strengthen the heart, and calm the spirit—skillfully linking heart, spleen, kidney, qi, blood and brain as a whole to treat age-related dementia. The purpose of this review is to outline TCM concepts for the treatment of dementia and illustrated with a historical prescription for the treatment of the condition, with the hope that this description may lead to advances in its management.

Cerebral Perfusion Enhancing Interventions: A New Strategy for the Prevention of Alzheimer Dementia

Cardiovascular and cerebrovascular diseases are major risk factors in the development of cognitive impairment and Alzheimer's disease (AD). These cardio-cerebral disorders promote a variety of vascular risk factors which in the presence of advancing age are prone to markedly reduce cerebral perfusion and create a neuronal energy crisis. Long-term hypoperfusion of the brain evolves mainly from cardiac structural pathology and brain vascular insufficiency. Brain hypoperfusion in the elderly is strongly associated with the development of mild cognitive impairment (MCI) and both conditions are presumed to be precursors of Alzheimer dementia. A therapeutic target to prevent or treat MCI and consequently reduce the incidence of AD aims to elevate cerebral perfusion using novel pharmacological agents. As reviewed here, the experimental pharmaca include the use of Rho kinase inhibitors, neurometabolic energy boosters, sirtuins and vascular growth factors. In addition, a compelling new technique in laser medicine called photobiomodulation is reviewed. Photobiomodulation is based on the use of low level laser therapy to stimulate mitochondrial energy production non-invasively in nerve cells. The use of novel pharmaca and photobiomodulation may become important tools in the treatment or prevention of cognitive decline that can lead to dementia.

Left ventricular hypertrophy in association with cognitive impairment: a systematic review and meta-analysis

Left ventricular hypertrophy (LVH) is a marker of prolonged exposure to high blood pressure and a predictor of cardiovascular disease risk. The objective of the current study was to investigate its association with cognitive function. Following standard guidelines, pairs of independent reviewers screened 2359 articles to search for studies that addressed the research question, extracted data and evaluated the quality of the studies using the Newcastle-Ottawa scale; authors were contacted for additional data. A random-effects meta-analysis and a meta-regression analysis were performed. Eighteen eligible studies using various methodologies and of varying quality were identified. However, both cross-sectional and prospective studies were indicative of a positive association between LVH and cognitive impairment or cognitive performance and decline in both population-based and patient-based subjects. The meta-analysis showed an increased risk of cognitive impairment among subjects with LVH in population-based studies (9 studies; 28 648 subjects; odds ratio (OR): 1.40, 95% confidence interval (CI): 1.18-1.66) and studies exclusively on hypertensive subjects (3 studies; 1262 subjects; OR: 2.14, 95% CI: 1.39-3.30). The effect was stronger when assessing LVH by echocardiography rather than electrocardiogram and was retained in the sensitivity analyses of prospective and highest quality studies and studies adjusting for hypertension or blood pressure levels. No heterogeneity or publication bias was documented, whereas the presence of hypertension seemed to reinforce the reported association, as derived from the meta-regression analysis. There is evidence suggesting an independent association of LVH with cognitive impairment. Because of the highly heterogeneous methodologies, future large prospective studies with clinically defined dementia outcomes are needed to replicate the findings.

Associations between Sleep, Cortisol Regulation, and Diet: Possible Implications for the Risk of Alzheimer Disease

Accumulation of proteinaceous amyloid β plaques and tau oligomers may occur several years before the onset of Alzheimer disease (AD). Under normal circumstances, misfolded proteins get cleared by proteasome degradation, autophagy, and the recently discovered brain glymphatic system, an astroglial-mediated interstitial fluid bulk flow. It has been shown that the activity of the glymphatic system is higher during sleep and disengaged or low during wakefulness. As a consequence, poor sleep quality, which is associated with dementia, might negatively affect glymphatic system activity, thus contributing to amyloid accumulation. The diet is another important factor to consider in the regulation of this complex network. Diets characterized by high intakes of refined sugars, salt, animal-derived proteins and fats and by low intakes of fruit and vegetables are associated with a higher risk of AD and can perturb the circadian modulation of cortisol secretion, which is associated with poor sleep quality. For this reason, diets and nutritional interventions aimed at restoring cortisol concentrations may ease sleep disorders and may facilitate brain clearance, consequentially reducing the risk of cognitive impairment and dementia. Here, we describe the associations that exist between sleep, cortisol regulation, and diet and their possible implications for the risk of cognitive impairment and AD.

Executive function, but not memory, associates with incident coronary heart disease and stroke

OBJECTIVE

To evaluate the association of performance in cognitive domains executive function and memory with incident coronary heart disease and stroke in older participants without dementia.

METHODS

We included 3,926 participants (mean age 75 years, 44% male) at risk for cardiovascular diseases from the Prospective Study of Pravastatin in the Elderly at Risk (PROSPER) with Mini-Mental State Examination score ≥24 points. Scores on the Stroop Color-Word Test (selective attention) and the Letter Digit Substitution Test (processing speed) were converted to Z scores and averaged into a composite executive function score. Likewise, scores of the Picture Learning Test (immediate and delayed memory) were transformed into a composite memory score. Associations of executive function and memory were longitudinally assessed with risk of coronary heart disease and stroke using multivariable Cox regression models.

RESULTS

During 3.2 years of follow-up, incidence rates of coronary heart disease and stroke were 30.5 and 12.4 per 1,000 person-years, respectively. In multivariable models, participants in the lowest third of executive function, as compared to participants in the highest third, had 1.85-fold (95% confidence interval [CI] 1.39-2.45) higher risk of coronary heart disease and 1.51-fold (95% CI 0.99-2.30) higher risk of stroke. Participants in the lowest third of memory had no increased risk of coronary heart disease (hazard ratio 0.99, 95% CI 0.74-1.32) or stroke (hazard ratio 0.87, 95% CI 0.57-1.32).

CONCLUSION

Lower executive function, but not memory, is associated with higher risk of coronary heart disease and stroke. Lower executive function, as an independent risk indicator, might better reflect brain vascular pathologies.

Heart failure and Alzheimer's disease

It has recently been proposed that heart failure is a risk factor for Alzheimer's disease. Decreased cerebral blood flow and neurohormonal activation due to heart failure may contribute to the dysfunction of the neurovascular unit and cause an energy crisis in neurons. This leads to the impaired clearance of amyloid beta and hyperphosphorylation of tau protein, resulting in the formation of amyloid beta plaques and neurofibrillary tangles. In this article, we will summarize the current understanding of the relationship between heart failure and Alzheimer's disease based on epidemiological studies, brain imaging research, pathological findings and the use of animal models. The importance of atherosclerosis, myocardial infarction, atrial fibrillation, blood pressure and valve disease as well as the effect of relevant medications will be discussed.

Altered diastolic function and aortic stiffness in Alzheimer's disease

Background

Alzheimer’s disease (AD) is closely linked to cardiovascular risk factors.

Methods

Echocardiographic studies were performed, including left ventricular diastolic functions, left and right atrial conduction times, and arterial stiffness parameters, namely stiffness index, pressure-strain elastic modulus, and distensibility, on 29 patients with AD and 24 age-matched individuals with normal cognitive function.

Results

The peak mitral flow velocity of the early rapid filling wave (E) was lower, and the peak velocity of the late filling wave caused by atrial contraction (A), deceleration time of peak E velocity, and isovolumetric relaxation time were higher in the AD group. The early myocardial peak (E_a) velocity was significantly lower in AD patients, whereas the late diastolic (A_a) velocity and E/E_a ratio were similar between the two groups. In Alzheimer patients, stiffness index and pressure-strain elastic modulus were higher, and distensibility was significantly lower in the AD group compared to the control. Interatrial electromechanical delay was significantly longer in the AD group.

Conclusion

Our findings suggest that patients with AD are more likely to have diastolic dysfunction, higher atrial conduction times, and increased arterial stiffness compared to the controls of same sex and similar age.

Primary prevention of Alzheimer's disease: is it an attainable goal?

Alzheimer's disease (AD) is the leading cause of dementia, and the most prevalent neurodegenerative disease in the elderly. The prevalence of AD is predicted to rise as life expectancy grows across populations. The exact cause of this devastating disease is still unknown; however, it is an aging-related multi-factorial disorder, and growing evidence supports the contribution of modifiable environmental factors to unmodifiable factors such as gene and ageing itself. The recent advancement of methodologies and techniques for early diagnosis of AD facilitates the investigation of strategies to reduce the risk for AD progression in the earliest stages of the disease. Pharmacological attempts at curing, halting or modifying it have, by and large, been unsuccessful, and no breakthrough is seen in the near future. However, a lot of elements that seem to contribute to the disease such as risk factors have been identified, mainly from epidemiological and basic research studies. Many of these are amenable to lifestyle modification. Therefore, prevention in the preclinical stage is likely the most effective way to decrease the incidence of this age-associated dreadful neurodegenerative condition, and its associated burden for individuals and society. We provide an overview of modifiable risk factors for AD along with the supporting evidence.

Cardioprotection and anticholinesterases in patients with Alzheimer's disease: time for reappraisal

Background/Aim

Traditional risk factors, like impaired transmitral flow in diastolic filling [vortex formation time (VFT) as echocardiographic parameter], contribute to Alzheimer's disease (AD). Moreover, we observed that acetylcholinesterase inhibitors provide a significant cardioprotection. We assessed the pathogenetic role of VFT as early cardiovascular risk factor in 23 AD patients and 24 controls.

Results

The results showed no statistical difference between the two groups, but the VFT values were significantly lower in nontreated AD patients, and higher value were observed in AD patients treated with anticholinesterases.

Conclusions

The results support the beneficial effects of anticholinesterases on the cardiovascular system of AD patients. Thus, the transition to evidence-based medicine and an in vivo model of cardiomyocytes might strengthen these results.

QT dispersion in mild cognitive impairment: a possible tool for predicting the risk of progression to dementia?

OBJECTIVE

The aim of this research was to investigate relationships between cognitive function and non-invasive, repeatable cardiac parameters in elderly subjects suffering from mild cognitive impairment (MCI) or Alzheimer's disease (AD).

METHODS

Two hundred and twenty-four community-living elderly subjects, 31 AD patients, 77 MCI patients, and 116 cognitively normal subjects (CNS), were evaluated for cognitive abilities (Mini Mental State Examination score (MMSE)) and for electrocardiographic [corrected heart rate QT interval dispersion (QTcD)] and echocardiographic [Left ventricular ejection fraction (LVEF)] parameters.

RESULTS

Mean values of LVEF were not significantly different between the three groups; QTcD mean values were significantly lower in CNS group than in subjects with MCI and AD. The Pearson Product Moment Correlation test, carried out in the three study groups, showed a significant inverse correlation between QTcD and MMSE score (r = -0.357; p < 0.01) in the group of MCI patients, only. In multivariable-adjusted linear regression tests, QTcD (p = 0.030) and education (p = 0.021) are associated with MMSE score in MCI group. Only the parameter of education appears to predict MMSE in CNS group; none of these parameters appear to predict MMSE in the group of patients with AD.

CONCLUSION

The association between QTcD and MMSE requires cautious interpretation and further extensive investigation. However, if confirmed by longitudinal studies, the finding could play a role in the management of the subjects with MCI.

Heart disease as a risk factor for dementia

As life expectancy lengthens, dementia is becoming a significant human condition in terms of its prevalence and cost to society worldwide. It is important in that context to understand the preventable and treatable causes of dementia. This article exposes the link between dementia and heart disease in all its forms, including coronary artery disease, myocardial infarction, atrial fibrillation, valvular disease, and heart failure. This article also explores the cardiovascular risk factors and emphasizes that several of them are preventable and treatable. In addition to medical therapies, the lifestyle changes that may be useful in retarding the onset of dementia are also summarized.

Cardiovascular risk factors promote brain hypoperfusion leading to cognitive decline and dementia

Heart disease is the major leading cause of death and disability in the world. Mainly affecting the elderly population, heart disease and its main outcome, cardiovascular disease, have become an important risk factor in the development of cognitive decline and Alzheimer's disease (AD). This paper examines the evidence linking chronic brain hypoperfusion induced by a variety of cardiovascular deficits in the development of cognitive impairment preceding AD. The evidence indicates a strong association between AD and cardiovascular risk factors, including ApoE(4), atrial fibrillation, thrombotic events, hypertension, hypotension, heart failure, high serum markers of inflammation, coronary artery disease, low cardiac index, and valvular pathology. In elderly people whose cerebral perfusion is already diminished by their advanced age, additional reduction of cerebral blood flow stemming from abnormalities in the heart-brain vascular loop ostensibly increases the probability of developing AD. Evidence also suggests that a neuronal energy crisis brought on by relentless brain hypoperfusion may be responsible for protein synthesis abnormalities that later result in the classic neurodegenerative lesions involving the formation of amyloid-beta plaques and neurofibrillary tangles. Insight into how cardiovascular risk factors can induce progressive cognitive impairment offers an enhanced understanding of the multifactorial pathophysiology characterizing AD and ways at preventing or managing the cardiovascular precursors of this dementia.

Nutritional determinants of cognitive aging and dementia

The objective of this review is to provide an overview of nutritional factors involved in cognitive aging and dementia with a focus on nutrients that are also important in neurocognitive development. Several dietary components were targeted, including antioxidant nutrients, dietary fats and B-vitamins. A critical review of the literature on each nutrient group is presented, beginning with laboratory and animal studies of the underlying biological mechanisms, followed by prospective epidemiological studies and randomised clinical trials. The evidence to date is fairly strong for protective associations of vitamin E from food sources, the n-3 fatty acid, DHA, found in fish, a high ratio of polyunsaturated to saturated fats, and vitamin B12 and folate. Attention to the level of nutrient intake is crucial for interpreting the literature and the inconsistencies across studies. Most of the epidemiological studies that observe associations have sufficient numbers of individuals who have both low and adequate nutrient status. Few of the randomised clinical trials are designed to target participants who have low baseline status before randomising to vitamin supplement treatments, and this may have resulted in negative findings. Post-hoc analyses by some of the trials reveal vitamin effects in individuals with low baseline intakes. The field of diet and dementia is a relatively young area of study. Much further work needs to be done to understand dietary determinants of cognitive aging and diseases. Further, these studies must be particularly focused on the levels of nutrient intake or status that confer optimum or suboptimal brain functioning.

Patients with Alzheimer disease have altered transmitral flow: echocardiographic analysis of the vortex formation time

OBJECTIVE

There is considerable epidemiologic evidence that Alzheimer disease (AD) is linked to cardiovascular risk factors and associated with an increased risk of symptomatic left ventricular (LV) dysfunction. Formation of a vortex alongside a diastolic jet signifies an efficient blood transport mechanism. The vortex formation time (VFT) is an index of optimal conditions for vortex formation. We hypothesized that AD and its associated cardiovascular risk factors impair diastolic transmitral flow efficiency and, therefore, shift the VFT value out of its optimal range.

METHODS

Echocardiographic studies were performed on 45 participants in total: 22 patients with AD diagnosed according to the American Psychiatric Association's criteria and 23 age-matched individuals as a control group with cognitive function within normal limits.

RESULTS

The echocardiographic ratio of the early to atrial phases of the LV filling velocities was significantly lower in the AD group (mean +/- SD, 0.67 +/- 14) when compared with the control individuals (0.79 +/- 0.14; P = .003). The interventricular septum diastolic thickness, left ventricular posterior wall diastolic thickness, and right ventricular end-diastolic diameter were significantly higher in the AD group (P <or= 0.04). The mitral annular diameters in the control and AD groups were nearly identical (P = .725). The time-velocity integral of the E wave had a lower value in the AD group than in the control group (P = .05), whereas the VFT was significantly lower in the AD group (P = .018).

CONCLUSIONS

Our study suggests that patients with AD have impaired transmitral flow efficiency of diastolic filling, as measured by the VFT, compared with age-matched control individuals.

Carotid artery ultrasound and echocardiography testing to lower the prevalence of Alzheimer's disease

The use of two clinic office techniques, carotid artery ultrasound and echocardiography (CAUSE), to detect deficient brain blood flow delivery in the healthy, cognitively normal, older individual is proposed. Evidence indicates that persistent heart-to-brain blood flow deficit involving low cardiac output or low ejection fraction and carotid artery narrowing can promote cognitive impairment and that such impairment may lead to Alzheimer's disease (AD) or vascular dementia (VaD). A number of independent epidemiologic studies reported cardiovascular and cerebrovascular disease to be risk factors to AD and VaD. The clinical rationale for CAUSE is to detect and prevent progression of cognitive dysfunction in elderly persons and is based on the general understanding that mild cognitive impairment is a preclinical threshold to AD or VaD with high conversion rates to either dementia. The use of CAUSE is anticipated to prevent or attenuate, by appropriate clinical management, mild cognitive impairment arising from persistent brain hypoperfusion, a condition implicated in the promotion of cognitive impairment in the elderly and a common preclinical feature seen in AD and VaD. As detection of lowered cerebral perfusion from cardiac and carotid artery pathology is achieved using these cost-effective, noninvasive, and relatively accurate ultrasound procedures, a significant reduction in the number of new AD and VaD cases would be anticipated after appropriate patient treatment. In this context, a brief summary is presented outlining recent medical and surgical treatments that may improve cerebral blood flow insufficiency. The merit of CAUSE in screening and treating mentally healthy elderly persons who are identified as being at risk of cognitive decline is that it could blunt the soaring socioeconomic impact that will hammer the health care system of many nations by the mounting dementia prevalence rate expected in the next 25 years. A 5- year delay in the onset of AD could reduce the prevalence of AD by 50%. We are making preparations to test the merit of CAUSE in a clinical study of a cognitively healthy elderly population.

Acoustically evoked immediate early gene expression in the pallium of female túngara frogs

In anurans, much is known about the role of the auditory midbrain in processing conspecific calls, but comparatively little is known about the role of the pallium. To address this deficiency, we investigated the induction of the immediate early gene egr-1 by natural mate chorus in the medial, dorsal, lateral, and ventral pallium of female túngara frogs. We found strong acoustically evoked egr-1 expression in the dorsal medial pallium (p < 0.01) and ventral pallium (p = 0.02), with a weaker effect in the lateral pallium (p = 0.05). In the ventral pallium, acoustically induced egr-1 expression was stronger in the anterior portion. Measures of movement and olfactory activity could not explain a significant portion of acoustically evoked pallial egr-1 expression. In contrast, egr-1 expression in the auditory midbrain covaried with egr-1 expression in the dorsal medial pallium and ventral pallium, suggesting that their activity was coupled with auditory activity. Taken together, these results suggest that the acoustically evoked egr-1 expression in the dorsal medial pallium and ventral pallium were a direct result of auditory stimulation. Furthermore, although both anatomical and electrophysiological evidence demonstrate that multiple modalities overlap in the frog pallium, our results show that a multimodal stimulus is not required to activate pallial neurons. Although the functional role of the frog pallium is not known, our results demonstrate that species-specific sounds activate spatially segregated and anatomically distinct areas of the frog pallium, inviting further investigation into the role of the frog pallium in acoustic communication.

Depressive symptoms, vascular risk factors, and Alzheimer's disease

BACKGROUND

Depressive symptoms in the elderly are associated with an increased Alzheimer's disease (AD) risk. We sought to determine whether the association between depressive symptoms and AD is explained by a history of vascular risk factors and stroke.

METHODS

Five hundred and twenty-six elderly persons from New York City without dementia at baseline were followed for a mean of 5 years. Depressive symptoms were assessed using the 17-item Hamilton Depression Rating Scale (HAM). Incident AD was ascertained using standard criteria. Diabetes, hypertension, heart disease, current smoking and stroke were ascertained by self-report. Proportional hazards regression was used to relate HAM scores to incident AD.

RESULTS

HAM scores were higher in persons with hypertension, heart disease, and stroke, which in turn were related to higher AD risk. AD risk increased with increasing HAM scores as a continuous logarithmically transformed variable (HR for one point increase=1.4; 95% CI=1.1,1.8) and as a categorical variable (HR for HAM >or= 10=3.4; 95% CI=1.5,8.1; p for trend=0.004 with HAM=0 as the reference). These results were virtually unchanged after adjustment for vascular risk factors and stroke, individually (HR for HAM >or= 10=3.4; 95% CI=1.5,8.1; p for trend = 0.004), and in a composite measure (HR for HAM >or= 10=3.0; 95% CI=1.2,7.8; p for trend=0.02).

CONCLUSION

The prospective relation between depressive symptoms and AD is not explained by a history of vascular risk factors and stroke, suggesting that other mechanisms may account for this association.