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

Possible neurocognitive benefits of exercise in persons with heart failure

More than 6 million Americans have heart failure (HF) and more than 500,000 are diagnosed each year. In addition to its many adverse medical consequences, HF is also a significant risk factor for neurological disorders like Alzheimer's disease and associated with cognitive impairment long prior to the onset of these conditions. Converging bodies of literature suggest cognitive dysfunction in HF may be at least partially modifiable. One key mechanism for cognitive improvement is improved cerebral blood flow, which may be possible with exercise in patients with HF. This brief review provides a model for the likely neurocognitive benefits of exercise in HF and encourages further work in this area.

The presence of cerebral and/or systemic endothelial dysfunction in patients with leukoaraiosis--a case control pilot study

BACKGROUND

In spite of high prevalence and clinical relevance of leukoaraiosis (LA), its pathophysiology is still incompletely understood. Theories of ischaemic genesis and a leaky blood-brain barrier are contradictory yet could share a common denominator-endothelial dysfunction (cerebral, systemic or both), which has not been studied thoroughly in LA.

METHODS

Thirty patients with LA (58 years (SD 7)) and 30 gender- and age-matched controls without LA (55 years (SD 6)) were recruited. The vascular risk factors (VRF) were identical in both groups. Cerebral endothelial function was determined by cerebrovascular reactivity to L-arginine (CVR). Systemic endothelial function was determined by flow-mediated dilatation (FMD) of the brachial artery after hyperaemia. All participants underwent a brain MRI to search for radiological signs of LA that was classified according to the Fazekas score. Linear regression was used to explore the correlation between CVR and FMD in patients with LA. A 95 % confidence interval was used. For any statistical test used in the study, p ≤ 0.050 was regarded as statistically significant.

RESULTS

We found a marked and significant decrease in both CVR (9.6 % (SD 3.2) vs. 15.8 % (SD 6.1), p < 0.001) and FMD (4.8 % (SD 3.1) vs. 7.4 % (SD 3.8), p = 0.004) in LA patients compared to controls. Both CVR (7.4 % (SD 3.1) vs. 12.2 % (SD 2.6), p = 0.001) and FMD (3.0 % (SD 2.2) vs. 6.4 % (SD 3.1), p = 0.011) were significantly decreased in LA subgroup Fazekas 3 compared to subgroup Fazekas 1. CVR and FMD significantly positively correlated (b = 0.192, 95 % CI = 0.031-0.354, p = 0.02).

CONCLUSIONS

The results of our pilot study suggest that patients with LA have a significant impairment of both cerebral and systemic endothelial function that is larger than could be expected based on present VRF. Endothelial dysfunction increases in parallel with LA severity and correlates between cerebral and systemic arterial territory. Overall, our results suggest a so far unknown "intrinsic" generalised endothelial dysfunction in patients with LA that could be involved in LA pathophysiology. This interesting issue needs to be confirmed in larger samples since it could help better understand the mechanisms underlying LA.

Slowed peak resting frequency and MEG overactivation in survivors of severe sepsis and septic shock

OBJECTIVE

Survivors of severe sepsis and septic shock suffer from residual severe cognitive impairments, which persist even years after intensive care unit (ICU) discharge. As the awareness of long-term consequences gradually grows, research has focused on cognitive impairments via questionnaires, but only few have focused on structural or electrophysiological features, such as the peak resting frequency, which is commonly seen as a hallmark of brain function.

METHODS

We aimed to analyze the long-term progression of the peak resting activity in terms of frequency and power in sepsis survivors. Healthy individuals with no history of ICU stay served as controls. Data were collected three times (shortly, 6 and 12 months after ICU discharge) in sepsis survivors and three times in controls. Participants also underwent behavioral neuropsychological assessment.

RESULTS

Sepsis survivors exhibited significantly higher spectral power of the dominant peak, which was shifted towards lower frequencies. Within one year, resting frequency increased to the level of controls, but power did not decrease. We observed a close correlation between resting frequency and mental status.

CONCLUSIONS

Results support the assumption of a causal relationship between brain oscillations and behavioral performance.

SIGNIFICANCE

We suggest that the postseptic frequency shift is due to abnormal thalamocortical dynamics.

Telomere G-tail Length is a Promising Biomarker Related to White Matter Lesions and Endothelial Dysfunction in Patients With Cardiovascular Risk: A Cross-sectional Study

Background

The telomeric 3′-overhang (G-tail) length is essential for the biological effects of telomere dysfunction in vitro, but the association of length with aging and cardiovascular risk is unclear in humans. We investigated the association between the telomere G-tail length of leukocytes and cardiovascular risk, age-related white matter changes (ARWMCs), and endothelial function.

Methods

Patients with a history of cerebrovascular disease and comorbidity were enrolled (n = 102; 69 males and 33 females, 70.1 ± 9.2 years). Total telomere and telomere G-tail lengths were measured using a hybridization protection assay. Endothelial function was evaluated by ultrasound assessment of brachial flow-mediated dilation (FMD).

Findings

Shortened telomere G-tail length was associated with age and Framingham risk score (P = 0.018 and P = 0.012). In addition, telomere G-tail length was positively correlated with FMD values (P = 0.031) and negatively with the severity of ARWMCs (P = 0.002). On multivariate regression analysis, telomere G-tail length was independently associated with FMD values (P = 0.022) and the severity of ARWMCs (P = 0.033), whereas total telomere length was not associated with these indicators.

Interpretation

Telomere G-tail length is associated with age and vascular risk factors, and might be superior to total telomere length as a marker of endothelial dysfunction and ARWMC severity.

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Telomere G-tail length was measured using a hybridization protection assay in patients with vascular risk factors.

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Telomere G-tail length was independently related to endothelial function and age-related white matter changes.

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Telomere G-tail length might be a promising biomarker of vascular damage.

Metabolic determinants of white matter hyperintensity burden in patients with ischemic stroke

OBJECTIVE

Increasing white matter hyperintensity (WMH) burden is linked to risk of stroke and poor post-stroke outcomes. While the biology of WMH remains ill-defined, several lines of evidence implicate endothelial dysfunction. In this study, we sought to assess the association between metabolic markers of endothelial dysfunction and WMH severity in patients with acute ischemic stroke (AIS).

METHODS

In this retrospective study, consecutive subjects, ≥18 years of age, admitted to our ED with AIS, brain MRI, and blood homocysteine (Hcy) and hemoglobin A1c (HgbA1c) measurements were eligible for this analysis. WMH volume (WMHV) was quantified using a validated semi-automated algorithm and log-transformed for linear regression analyses.

RESULTS

There were 809 AIS subjects included (mean age 65.57±14.7, median WMHV 6.25 cm3 (IQR 2.8-13.1)). In univariate analysis, age, female gender, race, ethnicity, systolic blood pressure, history of hypertension, atrial fibrillation, coronary artery disease, prior stroke, and current alcohol and tobacco use (all p<0.05), as well as Hcy (p<0.0001) and HgbA1c levels (p=0.0005) were associated with WMHV. However, only Hcy (β=0.11, p=0.003) and HgbA1c levels (β=0.1, p=0.008) independently predicted WMHV in the multivariate model, along with age (β=0.03, p<0.0001), race (β=0.39, p=0.01), ethnicity (β=-0.11, p=0.03), and current alcohol use (β=0.26, p=0.002).

CONCLUSIONS

Elevated levels of Hcy and HgbA1c have been previously linked to endothelial dysfunction related to oxidative stress. The association between Hcy and HgbA1c and WMH burden in AIS suggests that the degree of endothelial dysfunction may be greater in patients with increased WMHV, and may in part explain the relationship between WMHV and poor post-stroke outcomes.

Endothelial dysfunction is associated with the severity of cerebral small vessel disease

The pathogenesis of cerebral small vessel disease, a disease that involves white matter lesions (WMLs) and cerebral microbleeds (CMBs), is thought to be associated with endothelial dysfunction. Flow-mediated dilation (FMD) has been used to measure endothelium-dependent vasodilation. The aim of this study was to investigate the association between endothelial function (as measured by FMD) and cerebral small vessel disease. Patients with a history of cerebrovascular disease and comorbidities were enrolled in this study (n=102; 69 males, 70.1±9.2 years). The patients were divided into two groups according to the severity of WMLs, which were assessed by Fazekas classification; grades 0 to 1 as mild WMLs group and grades 2 to 3 as severe WMLs group. A gradient-echo MRI was performed in 96 patients (94.1%) to evaluate whether CMBs were present. The patients in the severe WMLs group (n=40) were older (P=0.001), more frequently exhibited hypertension (P=0.045) and diabetes mellitus (P=0.026) and possessed lower FMD values (P<0.001) than the patients in the mild WMLs group (n=62). CMBs were observed in 30 patients (31.3%). Using receiver operating characteristic curves, the optimal FMD cutoff values for predicting the presence of severe WMLs and CMBs were 3.9% and 3.7%, respectively. On multivariate logistic analysis, FMD <4.0% (odds ratio 9.50; 95% confidence interval 3.55-28.83) was independently associated with severe WMLs. Additionally, FMD <3.8% (5.82; 2.23-16.50) was also associated with the presence of CMBs. Endothelial dysfunction as evaluated by FMD may be predictive of the severity of cerebral small vessel disease.

Serum IgG antibody levels to periodontal microbiota are associated with incident Alzheimer disease

Background

Periodontitis and Alzheimer disease (AD) are associated with systemic inflammation. This research studied serum IgG to periodontal microbiota as possible predictors of incident AD.

Methods

Using a case-cohort study design, 219 subjects (110 incident AD cases and 109 controls without incident cognitive impairment at last follow-up), matched on race-ethnicity, were drawn from the Washington Heights-Inwood Columbia Aging Project (WHICAP), a cohort of longitudinally followed northern Manhattan residents aged >65 years. Mean follow-up was five years (SD 2.6). In baseline sera, serum IgG levels were determined for bacteria known to be positively or negatively associated with periodontitis (Porphyromonas gingivalis, Tannerella forsythia, Actinobacillus actinomycetemcomitans Y4, Treponema denticola, Campylobacter rectus, Eubacterium nodatum, and Actinomyces naeslundii genospecies-2). In all analyses, we used antibody threshold levels shown to correlate with presence of moderate-severe periodontitis.

Results

Mean age was 72 years (SD 6.9) for controls, and 79 years (SD 4.6) for cases (p<0.001). Non-Hispanic Whites comprised 26%, non-Hispanic Blacks 27%, and Hispanics 48% of the sample. In a model adjusting for baseline age, sex, education, diabetes mellitus, hypertension, smoking, prior history of stroke, and apolipoprotein E genotype, high anti-A. naeslundii titer (>640 ng/ml, present in 10% of subjects) was associated with increased risk of AD (HR = 2.0, 95%CI: 1.1–3.8). This association was stronger after adjusting for other significant titers (HR = 3.1, 95%CI: 1.5–6.4). In this model, high anti-E. nodatum IgG (>1755 ng/ml; 19% of subjects) was associated with lower risk of AD (HR = 0.5, 95%CI: 0.2–0.9).

Conclusions

Serum IgG levels to common periodontal microbiota are associated with risk for developing incident AD.

Erectile dysfunction, vascular risk, and cognitive performance in late middle age

Vascular disease is the most common etiology of erectile dysfunction (ED). Men with ED are at a 65% increased relative risk of developing coronary heart disease and a 43% increased risk of stroke within 10 years. Vascular disease is associated with cognitive impairment; ED-an overt manifestation of vascular dysfunction-could also signal early compromised cognition. We sought to determine whether cognitive differences existed between men with ED and healthy peers. Our sample consisted of 651 men (ages 51-60 years) from the Vietnam Era Twin Study of Aging. ED was associated with poorer cognitive performance, particularly on attention-executive-psychomotor speed tasks. ED remained significantly associated with cognition after inclusion of other cardiovascular risk factors (including hypertension, high cholesterol, body mass index, and smoking). These findings underscore the importance of further study of ED as a predictor of cognitive and cardiovascular health. (PsycINFO Database Record (c) 2014 APA, all rights reserved).

Association of intracranial atherosclerotic stenosis with severity of white matter hyperintensities

BACKGROUND AND PURPOSE

White matter hyperintensities (WMHs) on magnetic resonance imaging (MRI) have been linked to small-vessel disease, but the precise pathogenesis underlying WMHs remains unclear. Studies about an association of WMHs with extracranial atherosclerotic stenosis (ECAS) showed conflicting results and the relationship of WMHs with intracranial atherosclerotic stenosis (ICAS) is uncertain.

METHODS

A cross-sectional study of 679 consecutive Korean patients with acute ischaemic stroke (mean age 67.8 ± 12.6; 395 males) who underwent brain MRI/MR angiography was conducted. Severity of deep WMHs (d-WMHs, n = 560) and periventricular WMHs (p-WMHs, n = 590) was rated separately and compared across three groups: ICAS (n = 318), ECAS (n = 71) and no cerebral atherosclerotic stenosis (NCAS) (n = 290).

RESULTS

The ICAS group showed a higher d-WMH/p-WMH score (1.62 ± 0.85/1.65 ± 0.79) than both the ECAS (1.25 ± 0.87/1.23 ± 0.78) and NCAS (1.19 ± 0.92/1.24 ± 0.81) groups (P < 0.001 for all). Patients with a greater number of ICAS were more likely to have higher scores of d-WMH/p-WMH (P < 0.001 for all). Patients with higher scores of d-WMH/p-WMH had a higher incidence of ICAS (P < 0.001 for all), but not of ECAS or NCAS. In multivariable analysis, a dose-response relationship was observed between the extent of ICAS versus WMHs. Compared with one ICAS lesion, for d-WMHs the odds ratio (OR) = 2.61 [95% confidence interval (CI) 0.95-7.20] for two ICAS lesions and OR = 3.37 (1.10-10.32) for ≥3 ICAS lesions; whilst for p-WMHs (score ≥2) OR = 1.70 (95% CI 0.96-2.98) for two ICAS lesions and OR = 2.02 (1.15-3.55) for ≥3 ICAS lesions.

CONCLUSION

ICAS is independently associated with progressively greater WMH burden. The association of ICAS with WMH severity appears to be stronger than that of ECAS/NCAS in the Korean (Asian) stroke population.

Increased body mass index makes an impact on brain white-matter integrity in adults with remitted first-episode mania

BACKGROUND

Obesity is increasingly prevalent in bipolar disorder (BD) but data about the impact of elevated body mass index (BMI) on brain white-matter integrity in BD are sparse. Based on extant literature largely from structural magnetic resonance imaging (MRI) studies, we hypothesize that increased BMI is associated with decreased fractional anisotropy (FA) in the frontal, temporal, parietal and occipital brain regions early in the course of BD.

METHOD

A total of 26 euthymic adults (12 normal weight and 14 overweight/obese) with remitted first-episode mania (FEM) and 28 controls (13 normal weight and 15 overweight/obese) matched for age, handedness and years of education underwent structural MRI and diffusion tensor imaging scans.

RESULTS

There are significant effects of diagnosis by BMI interactions observed especially in the right parietal lobe (adjusted F(1,48) = 5.02, p = 0.030), occipital lobe (adjusted F(1,48) = 10.30, p = 0.002) and temporal lobe (adjusted F(1,48) = 7.92, p = 0.007). Specifically, decreased FA is found in the right parietal (F(1,48) = 5.864, p = 0.023) and occipital lobes (F(1,48) = 4.397, p = 0.047) within overweight/obese patients compared with normal-weight patients with FEM. Compared with overweight/obese controls, decreased FA is observed in right parietal (F(1,48) = 6.708, p = 0.015), temporal (F(1,48) = 10.751, p = 0.003) and occipital (F(1,48) = 9.531, p = 0.005) regions in overweight/obese patients with FEM.

CONCLUSIONS

Our findings suggest that increased BMI affects temporo-parietal-occipital brain white-matter integrity in FEM. This highlights the need to further elucidate the relationship between obesity and other neural substrates (including subcortical changes) in BD which may clarify brain circuits subserving the association between obesity and clinical outcomes in BD.

C-reactive protein and cognition are unrelated to leukoaraiosis

Elevated serum levels of C-reactive protein (CRP) have been associated with leukoaraiosis in elderly brain. However, several studies indicate that leukoaraiosis is associated with an increased risk of cognitive impairment. It is unknown how the effect of CRP on cognition is mediated by leukoaraiosis. The purpose of this study is to assess the relationship between serum levels of CRP, the presence of leukoaraiosis, and cognitive impairment in a population of coronary patients over 50 years old. CRP levels explained 7.18% (P: 0.002) of the variance of the MMSE. The adjustment for the presence of leukoaraiosis little changed this variance (5.98%, P: 0.005), indicating that only a small portion of the CRP influence on cognition was mediated via leukoaraiosis. Patients with CRP levels ≥5.0 had 2.9 (95% CI: 1.26–6.44) times more chance to present cognitive impairment (P: 0.012). We found that elevated serum levels of CRP were associated with increased risk of cognitive impairment in elderly and it was not mediated by presence of leukoaraiosis.

Characterizing white matter health and organization in atherosclerotic vascular disease: a diffusion tensor imaging study

Atherosclerotic vascular disease (AVD) is endemic to the developed world, with known negative outcomes for cognition and brain health. The effects of AVD on the white matter fibers of the brain have not yet been studied using diffusion tensor imaging (DTI). This study examined differences in fractional anisotropy (FA) between AVD and healthy comparison (HC) participants, and described the regional patterns of FA in each group. AVD participants were hypothesized to have lower FA than HC participants, indicating abnormalities in white matter health or organization. 1.5 T diffusion tensor imaging was performed in 35 AVD and 22 HC participants. Mean FA measures were calculated for the white matter of the whole brain, as well for individual lobes. Globally and in every brain region measured except the temporal lobes, there were significant effects of group where AVD participants had lower FA values than their HC counterparts. Group differences in FA remained significant when controlled for white matter hyperintensity (WMH) volume, suggesting that FA detects white matter abnormality above and beyond what is measurable using the older WMH technique. These findings suggest a likely neural substrate underlying the changes in cognition and mood reported in atherosclerotic vascular disease patients.

Albuminuria and cognitive decline in people with diabetes and normal renal function

BACKGROUND AND OBJECTIVES

Diabetes mellitus is associated with increased risk of cognitive impairment. This study examines whether microvascular disease, as measured by albuminuria and decline in estimated GFR (eGFR), is associated with cognitive decline during 3.3 years of follow-up in individuals with diabetes with a normal baseline eGFR (approximately 90 ml/min per 1.73 m(2)).

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

Participants were from the Action to Control Cardiovascular Risk in Diabetes Memory in Diabetes study (N=2977; mean age 62.5 ± 5.8 years; recruitment from August 2003 to December 2005, followed through June 2009), which examined the association of intensive versus standard glucose control on cognitive function. Participants underwent three neuropsychologic tests at baseline, 20 months, and 40 months. Tests included information processing speed, verbal memory, and executive function. Mixed-effects models were used to assess the association of albuminuria and eGFR on the percentage decline in each test.

RESULTS

Participants with albuminuria at baseline and follow-up (persistent albuminuria) (-5.8% [95% confidence interval (CI), -7.3 to -4.2]) and participants with albuminuria at follow-up but none at baseline (progressive albuminuria) (-4.1% [95% CI, -5.6 to -2.7]) had greater percentage declines on information processing speed than participants without albuminuria at baseline and at follow-up (no albuminuria) (-2.6% [95% CI, -3.4 to -1.9]) (P=0.001 and P=0.10, respectively). There were borderline percentage changes in the test of verbal memory (4.8% [95% CI, 2.4 to 7.1] and 4.7% [95% CI, 2.5 to 7.0] versus 7.1% [95% CI, 6.0 to 8.3]; P=0.11 and P=0.08, respectively). On logistic regression analysis, persistent albuminuria (odds ratio, 1.37 [95% CI, 1.09 to 1.72]) and progressive albuminuria (odds ratio, 1.25 [95% CI, 1.02 to 1.56]) were associated with a ≥ 5% decline in information processing speed scores but not with verbal memory or executive function performance. A 1 ml/min per 1.73 m(2) per year eGFR decline had a borderline association with decline in tests of cognitive function.

CONCLUSIONS

Persistent albuminuria and progressive albuminuria are associated with a decline in cognitive function in relatively young individuals with diabetes with unimpaired eGFR. These findings do not rule out the possibility of other processes causing cognitive decline.

Arterial stiffness and endothelial function are related to brain aging and episodic memory in community-dwelling middle-aged and older adults

Evaluation of: Tsao CW, Seshadri S, Beiser AS et al. Relations of arterial stiffness and endothelial function to brain aging in the community. Neurology 81, 1–8 (2013). This study reports the association between arterial stiffness and pressure pulsatility in middle-aged and older community-dwelling adults. As part of the Stroke- and Dementia-free Framingham Offspiring Study, 1587 participants were studied for tonometric arterial stiffness and endothelial function (years 1998–2001), and had MRI brain scans and cognitive assessments (1990–2002). The measures of the central aortic hemodynamics (e.g., carotid–femoral pulse wave velocity and mean arterial and central pulse pressure) were associated with greater white matter hyperintensity volumes and lower total cerebral brain volumes; this association was stronger for participants aged 65 years or older. The mean arterial and central pulse pressure were also associated with reduced verbal memory (p < 0.05) but not executive function. The brachial artery endothelial function was not associated with cerebral changes. These findings indicate that peripheral vascular changes are related not only to distal cerebral microvascular pathology, but may also be used as a surrogate marker for subclinical stages of cognitive dysfunction.

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

OBJECTIVE

To determine the association of arterial stiffness and pressure pulsatility, which can damage small vessels in the brain, with vascular and Alzheimer-type brain aging.

METHODS

Stroke- and dementia-free Framingham Offspring Study participants (n = 1,587, 61 ± 9 years, 45% male) underwent study of tonometric arterial stiffness and endothelial function (1998-2001) and brain MRI and cognition (1999-2002). We related carotid-femoral pulse wave velocity (CFPWV), mean arterial and central pulse pressure, and endothelial function to vascular brain aging by MRI (total cerebral brain volume [TCBV], white matter hyperintensity volume, silent cerebral infarcts) and vascular and Alzheimer-type cognitive aging (Trails B minus Trails A and logical memory-delayed recall, respectively).

RESULTS

Higher CFPWV was associated with lower TCBV, greater white matter hyperintensity volume, and greater prevalence of silent cerebral infarcts (all p < 0.05). Each SD greater CFPWV was associated with lower TCBV equivalent to 1.2 years of brain aging. Mean arterial and central pulse pressure were associated with greater white matter hyperintensity volume (p = 0.005) and lower TCBV (p = 0.02), respectively, and worse verbal memory (both p < 0.05). Associations of tonometry variables with TCBV and white matter hyperintensity volume were stronger among those aged 65 years and older vs those younger than 65 years (p < 0.10 for interaction). Brachial artery endothelial function was unrelated to MRI measures (all p > 0.05).

CONCLUSIONS

Greater arterial stiffness and pressure pulsatility are associated with brain aging, MRI vascular insults, and memory deficits typically seen in Alzheimer dementia. Future investigations are warranted to evaluate the potential impact of prevention and treatment of unfavorable arterial hemodynamics on neurocognitive outcomes.

Interactive relations of blood pressure and age to subclinical cerebrovascular disease

OBJECTIVE

To examine interactive relations of blood pressure (BP) and age to MRI indices of subclinical cerebrovascular disease in middle-aged to older adults.

METHODS

One hundred and thirteen stroke-free and dementia-free, community-dwelling adults (ages 54-81 years; 65% men; 91% white) engaged in (1) clinical assessment of resting SBP and DBP; (2) MRI rated for periventricular white matter hyperintensities (WMH) and deep WMH silent brain infarction (SBI) and brain atrophy (i.e. ventricular enlargement and sulcal widening ). Principal components analysis of the MRI ratings yielded a two-component solution--(1) periventricular and deep WMH SBI; and (2) ventricular enlargement, sulcal widening.

RESULTS

Relations of SBP, DBP and pulse pressure (PP) (and their interactions with age) to each MRI component were examined in multiple regression analyses adjusted for age, sex, fasting plasma glucose and cholesterol, and antihypertensives. For component 1, results indicated significant interactions of SBP and PP with age (P < 0.05); higher levels of SBP and PP were associated with greater white matter disease and brain infarction at younger ages (≤ 68 years). Significant interactions of SBP and DBP with age were also noted for component 2 (P < 0.05); higher levels of BP were associated with greater brain atrophy at younger ages (≤ 63 years).

CONCLUSION

: Higher BP and PP are associated with greater subclinical cerebrovascular disease most prominently in the 'young old'. Appropriate management of hypertension and arterial stiffening may be critical to the preservation of brain structure with ageing.

Brain diffusion changes in obstructive sleep apnoea syndrome

BACKGROUND

Obstructive sleep apnoea syndrome (OSAS) is a disorder characterized by repeated apnoeic episodes during sleep. Neurocognitive changes secondary to OSAS are likely to occur due to hypoxia in certain brain locations. Advances in magnetic resonance imaging technology, such as diffusion-weighted imaging (DWI), enable non-invasive and accurate identification of OSAS-induced changes.

OBJECTIVE

We aimed to use DWI to investigate changes in the brain secondary to hypoxia in OSAS.

METHODS

Eighty-eight patients underwent polysomnography and were classified as non-OSAS, mild-moderate OSAS and severe OSAS sufferers. DWI was used to evaluate 14 areas of the brain, and apparent diffusion coefficients (ADCs) were calculated. We investigated whether there were differences in the ADC values in specific areas of the brain between the non-OSAS and OSAS patients.

RESULTS

We measured the ADC values of the 68 newly diagnosed OSAS patients (21 mild, 15 moderate and 32 severe) and of 20 healthy controls. There were significant increases in the ADC values in the hippocampus, amygdala and putamen in OSAS patients. Compared to the non-OSAS subjects, the ADC values of the putamen in severe OSAS patients, those of the hippocampus in moderate or severe OSAS patients and those of the amygdala in moderate OSAS patients were significantly increased. A negative correlation between the lowest oxygen saturation during sleep and the ADC values of the hippocampus and amygdala was found.

CONCLUSIONS

Increased ADC levels in the hippocampus, amygdala and putamen in OSAS patients indicate hypoxia and likely cause vasogenic oedema in specific regions of the brain.

Pulse pressure and mild cognitive impairment

OBJECTIVE

Patients with suboptimal blood pressure (BP) control may remain with an elevated cardiovascular risk and risk for cognitive impairment. Pulse pressure (PP) assessed with ambulatory BP monitoring (ABPM) or self-measurement so far has been an underestimated risk factor for target organ damage.

METHODS

One hundred and forty-eight patients were screened: 51 men (34.5%) and 97 women (65.5%), mean age 64.16 ± 11.18 years and a mean hypertension history of 13.1 ± 11.05 years. We gathered full medical and hypertension history, physical examination, laboratory screening and ambulatory blood pressure monitoring. Neuropsychological profile was assessed with tests (NPTs): Mini Mental State Examination (MMSE) and Montreal Cognitive Assessment (MoCA).

RESULTS

Regression analysis found a correlation between day and night PP and NPT results. Mann-Whitney Test (α less than 0.05) was used to find a significant difference (P = 0.02 for MMSE) in the mean values of the NPT results between the groups with PP more than 50 and PP 50  mmHg or less. The result was not age dependent. There was also a significant difference between mean values of day-PP (P = 0.01) and night-PP (P = 0.02) between patients with cognitive impairment and those without (respectively more than 55  mmHg and less than 55  mmHg).

CONCLUSION

Elevated PP during the day, the night or with self-measurement is correlated with cognitive impairment. It is a marker of large artery stiffness and target organ damage not only in the very elderly, but also in younger individuals (mean age 64.16 years).

Cerebral perfusion is associated with white matter hyperintensities in older adults with heart failure

Cognitive impairment is common in heart failure (HF) and believed to be the result of cerebral hypoperfusion and subsequent brain changes including white matter hyperintensities (WMHs). The current study examined the association between cerebral blood flow and WMHs in patients with HF and the relationship between WMHs and cognitive impairment. Sixty-nine patients with HF completed the Mini-Mental State Examination (MMSE) and underwent echocardiography, transcranial Doppler sonography for cerebral blood flow velocity of the middle cerebral artery, and brain magnetic resonance imaging. Multivariable hierarchical regression analyses controlling for medical and demographic characteristics as well as intracranial volume showed reduced cerebral blood flow velocity of the middle cerebral artery was associated with greater WMHs (β=-0.34, P=.02). Follow-up regression analyses adjusting for the same medical and demographic factors in addition to cerebral perfusion also revealed marginal significance between increased WMHs and poorer performance on the MMSE (β=-0.26, P=.05). This study suggests that reduced cerebral perfusion is associated with greater WMHs in older adults with HF. These findings support the widely proposed mechanism of cognitive impairment in HF patients and prospective studies are needed to confirm these results.

Reduced heart rate recovery is associated with poorer cognitive function in older adults with cardiovascular disease

Cardiovascular disease (CVD) in older adults has been associated with varying degrees of cognitive dysfunction. Several mechanisms may explain this association, including impaired cardiovascular reactivity to autonomic nervous system (ANS) signaling. Reduced heart rate recovery following a stress test may be considered an indication of impaired ANS function (i.e., reduced parasympathetic activity). Participants were 47 older adults (53–83 years) who underwent a treadmill stress test and were administered a comprehensive neuropsychological battery upon entry to phase II cardiac rehabilitation. Reduced parasympathetic activity was associated with impaired cognitive performance on a measure of global cognitive function and on tasks of speeded executive function and confrontation naming. These relationships suggest that changes in autonomic function may be mechanistically related to the impaired cognitive function prevalent in CVD patients.

Cognitive impairment in diabetic patients: Can diabetic control prevent cognitive decline?

It is well recognized that the prevalence of dementia is higher in diabetic patients than non‐diabetic subjects. The incidence of diabetes has been increasing because of dramatic changes in lifestyles, and combined with longer lifespans as a result of advances in medical technology, this has brought about an increase in the number of elderly diabetic patients. Together, aging and diabetes have contributed to dementia becoming a serious problem. Progression to dementia reduces quality of life, and imposes a burden on both patients themselves and the families supporting them. Therefore, preventing the complication of dementia will become more and more important in the future. Although many mechanisms have been considered for an association between diabetes and cognitive dysfunction, glucose metabolism abnormalities such as hyperglycemia and hypoglycemia, and insulin action abnormalities such as insulin deficiency and insulin resistance can be causes of cognitive impairment. Recent large‐scale longitudinal studies have found an association between glycemic control and cognitive decline, although it is still unclear how cognitive decline might be prevented by good glycemic control. However, at an early stage, it is necessary to detect moderate cognitive dysfunction and try to reduce the risk factors for it, which should result in prevention of dementia, as well as vascular events. In the present review, in addition to outlining an association between diabetes and cognitive function, we discuss how glycemic control and cognitive decline are related.

Augmentation index is related to white matter lesions

The augmentation index (AIx) is a measure of pulse wave reflection from peripheral muscular conduit arteries, and is assumed to increase with stiffened arteries. A white matter lesion (WML) is generally regarded as a chronic ischemic lesion, which is associated with cerebral small-vessel arteriosclerosis. The aim of this study is to elucidate the effect of pulse wave reflection on the brain. Carotid AIx was measured in a total of 205 neurologically normal adults. The correlations between AIx and WML were investigated. Two categories of WML were evaluated, periventricular hyperintensity (PVH) and deep and subcortical white matter hyperintensity (DSWMH). On univariate analysis, AIx was significantly correlated with the grades of PVH and DSWMH (P=0.0001, respectively). On multivariate analysis, AIx was correlated with PVH and DSWMH, independent of other risk factors such as age or blood pressure. Pulse wave reflection from small vessels may influence the genesis of WML.

Structural brain changes and cognition in relation to markers of vascular dysfunction

The aim was to investigate the relationship between blood markers of vascular dysfunction with brain microstructural changes and cognition. Eighty-six participants from the Barcelona-Asymptomatic Intracranial Atherosclerosis (AsIA) neuropsychology study were included. Subjects were 50-65 years old, free from dementia and without history of vascular disease. We assessed correlations of blood levels of inflammatory biomarkers (C-reactive protein [CRP] and resistin) and fibrinolysis inhibitors (plasminogen activator inhibitor-1 [PAI-1] and A-lipoprotein (Lp (a)) with fractional anisotropy (FA) measurements of diffusion tensor images (DTI), regional gray matter (GM) volumes and performance in several cognitive domains. Increasing levels of C-reactive protein and PAI-1 levels were associated with white matter (WM) integrity loss in corticosubcortical pathways and association fibers of frontal and temporal lobes, independently of age, sex and vascular risk factors. PAI-1 was also related to lower speed and visuomotor/coordination. None of the biomarkers were related to gray matter volume changes. Our findings suggest that inflammation and dysregulation of the fibrynolitic system may be involved in the pathological mechanisms underlying the WM damage seen in cerebrovascular disease and subsequent cognitive impairment.

Functional magnetic resonance imaging of working memory reveals frontal hypoactivation in middle-aged adults with cognitive complaints

Older adults with cardiovascular disease (CVD) often complain about cognitive difficulties including reduced processing speed and attention. On cross-sectional examination, such reports relate more closely to mood than to cognitive performance; yet, in longitudinal studies, these complaints have foreshadowed cognitive decline over time. To test the hypothesis that self-reported cognitive difficulties reflect early changes in brain function, we examined cognitive complaints and depression in relation to blood oxygen level dependent (BOLD) response to a cognitive task in middle-aged adults at risk for CVD. Forty-nine adults (ages 40 to 60 years) completed a measure of perceived cognitive dysfunction (Cognitive Difficulties Scale), medical history questionnaire, neuropsychological assessment and functional magnetic resonance imaging (fMRI) during a working memory task. Increased report of cognitive difficulties was significantly associated with weaker task-related activation in the right superior frontal/ middle frontal gyrus (F(4,44) = 3.26; p = .020, CDS ß = -0.39; p = .009) and the right inferior frontal gyrus (F(4,44) = 3.14; p = .024, CDS ß = -0.45; p = .003), independent of age, education, and self-reported depressive symptoms. Lower activation intensity in the right superior frontal gyrus was related to trends toward poorer task performance. Thus, self-reported cognitive difficulties among cognitively normal middle-aged adults may provide important clinical information about early brain vulnerability that should be carefully monitored.

CAMTA1 T polymorphism is associated with neuropsychological test performance in older adults with cardiovascular disease

BACKGROUND

Cardiovascular disease has long been associated with poor neurocognitive outcome, with multiple pathophysiological mechanisms that are linked to cognitive impairment in older adults. Although less frequently examined, insulin dysregulation is known to affect vascular function and the associated brain dysfunction in cardiovascular disease. Accordingly, genetic factors tied to insulin regulation may make certain people with cardiovascular disease more susceptible to cognitive dysfunction. Specifically, the calmodulin-binding transcription activator 1 (CAMTA1) genotype, which has been examined as a risk factor for Type 2 diabetes and has been linked to reduced episodic memory performance in healthy young adults, is a potential candidate gene.

METHODS

Blood samples were obtained from 113 older adults with cardiovascular disease who also underwent neuropsychological testing. Carriers of either one or two copies of the T allele of CAMTA1 were categorized into one group (n = 63), whereas non-carriers were categorized into a second group (n = 50).

RESULTS

Analyses showed that carriers of the T allele performed more poorly on tests of attention, executive function, and psychomotor speed, but not on tests of memory. Carriers of the T allele also performed more poorly on a measure of global cognitive function.

CONCLUSIONS

Results indicate that CAMTA1 genotype is associated with cognitive function in older adults with cardiovascular disease, because carriers of the T allele performed more poorly on tests of attention, executive function, and psychomotor speed. Contrary to expectations, there were no differences in memory performance among carriers and non-carriers of the T allele. Given these mixed findings, further studies are necessary to elucidate the association between CAMTA1 and cognition, particularly gene expression and neuroimaging studies.

Slowing down: age-related neurobiological predictors of processing speed

Processing speed, or the rate at which tasks can be performed, is a robust predictor of age-related cognitive decline and an indicator of independence among older adults. This review examines evidence for neurobiological predictors of age-related changes in processing speed, which is guided in part by our source based morphometry findings that unique patterns of frontal and cerebellar gray matter predict age-related variation in processing speed. These results, together with the extant literature on morphological predictors of age-related changes in processing speed, suggest that specific neural systems undergo declines and as a result slow processing speed. Future studies of processing speed – dependent neural systems will be important for identifying the etiologies for processing speed change and the development of interventions that mitigate gradual age-related declines in cognitive functioning and enhance healthy cognitive aging.

Functional MR imaging evidence of altered functional activation in metabolic syndrome

BACKGROUND AND PURPOSE

MetS is a cluster of risk factors associated with significant cardiovascular morbidity and mortality and diminished cognitive function. Given that little is known about the early signs of brain vulnerability related to persistent metabolic dysfunction, we set out to determine whether cognitively healthy middle-aged individuals with MetS exhibit an altered cerebrovascular response to a cognitive challenge relative to those without MetS.

MATERIALS AND METHODS

Forty neurologically healthy adults aged 40-60 years (19 with MetS and 21 healthy controls) performed a 2-back verbal working memory task during fMRI. We compared BOLD responses between the 2 groups in 8 a priori regions of interest previously shown to be associated with the 2-back in patients with cardiovascular disease.

RESULTS

Age, education level, sex distribution, cognitive and emotional functioning, and task performance (accuracy and reaction time) were not different between the groups. Compared with healthy controls, individuals with MetS demonstrated a lower 2-back-related BOLD response in the right superior frontal gyrus, right superior parietal lobule, and left inferior parietal lobule.

CONCLUSIONS

This study provides preliminary evidence that cognitively intact middle-aged individuals with MetS exhibit significant alterations in cerebrovascular response to a cognitive challenge. Our results also demonstrate that fMRI may identify early brain changes associated with MetS.

Obesity is associated with reduced white matter integrity in otherwise healthy adults

Existing work demonstrates that obesity is independently associated with cognitive dysfunction and macrostructural brain changes; however, little is known about the association between obesity and white matter (WM) integrity. We explore this relationship in a large cohort of otherwise healthy subjects. The present study classified 103 adult participants from the Brain Resource International Database between 21 and 86 years of age without history of neurological, medical, or psychiatric illness according to BMI (normal weight, overweight, obese) and subjected them to diffusion tensor imaging (DTI). Resulting fractional anisotropy (FA) indexes for the corpus callosum and fornix were examined in relation to BMI and age in a multiple regression framework. Results indicated that increasing BMI was independently associated with lower FA in the genu, splenium, and fornix, and a BMI × age interaction emerged for FA in the splenium and body of the corpus callosum. When categorized, obese persons demonstrated lower FA than normal and overweight persons for all WM indexes, but no FA differences emerged between overweight and normal persons. Results indicate both a direct association between obesity and reduced WM tract integrity and an interaction between obesity and aging processes on certain WM tracts in otherwise healthy adults. While such findings suggest a possible role for adiposity in WM dysfunction and associated cognitive deficits, prospective studies are needed to clarify the nature of these relationships and elucidate underlying mechanisms.

Association of vascular health and neurocognitive performance in overweight adults with high blood pressure

The relationship between vascular health--including flow-mediated dilation (FMD) and intima medial thickness (IMT)--and neurocognitive performance was examined in a sample of 124 sedentary, middle-aged adults with high blood pressure (systolic blood pressure, SBP, 130-159 mmHg or diastolic blood pressure, DBP, 85-99 mmHg) who were overweight or obese (body mass index 25.0-39.99 kg/m²). Patients completed a neuropsychological test battery, including measures of executive function and psychomotor speed, and measures of IMT and FMD were obtained. Hierarchical multiple regression analyses were used to investigate the association between vascular measures and neurocognitive performance after controlling for demographic factors and cerebrovascular risk factors. Higher levels of FMD predicted better executive function (b = 0.90, p = .045). Greater IMT tended to be associated with slower psychomotor speed (b = -0.82, p = .084), with the effect attenuated after controlling for FMD. Impaired FMD is associated with worse neurocognitive functioning among overweight adults with high blood pressure.

Insulin sensitivity as a mediator of the relationship between BMI and working memory-related brain activation

Midlife obesity is associated with cognitive deficits and cerebral atrophy in older age. However, little is known about the early signs of these deleterious brain effects or the physiological mechanisms that underlie them. Functional magnetic resonance imaging (fMRI) allows us to detect early changes in brain response to cognitive challenges while behavioral performance is still intact. Accordingly, we examined the impact of obesity on functional activation during a 2-Back task in 32 cognitively normal middle-aged adults, who were classified into normal, overweight, and obese groups according to BMI. Additionally, we examined insulin sensitivity as a potential mediator of the relationship between BMI and brain activation. Insulin sensitivity is of special interest because insulin is strongly associated with both obesity and central nervous system functioning. Group differences in task-related brain activation were examined in a priori regions of interest (ROIs) using ANOVA. The obese BMI group displayed significantly lower task-related activation in the right parietal cortex, BA 40/7, (F(2,29) = 5.26, P = 0.011) than the normal (P = 0.016) and overweight (P = 0.047) BMI groups. Linear regression and bootstrapping methods for assessing indirect effects indicated that insulin sensitivity fully mediated the relationship between task-related activation in the right parietal cortex and BMI ((F(3,28) = 9.03, P = 0.000), β = 0.611, P = 0.001, 95% confidence interval: -2.548 to -0.468). In conclusion, obesity in middle age was related to alterations in brain activation during a cognitive challenge and this association appeared to be mediated by insulin sensitivity.

Systemic vascular function, measured with forearm flow mediated dilatation, in acute and stable cerebrovascular disease: a case-control study

Background

Acute ischaemic stroke is associated with alteration in systemic markers of vascular function. We measured forearm vascular function (using forearm flow mediated dilatation) to clarify whether recent acute ischaemic stroke/TIA is associated with impaired systemic vascular function.

Methods

Prospective case control study enrolling 17 patients with recent acute ischaemic stroke/TIA and 17 sex matched controls with stroke more than two years previously. Forearm vascular function was measured using flow medicated dilatation (FMD).

Results

Flow mediated dilatation was 6.0 ± 1.1% in acute stroke/TIA patients and 4.7 ± 1.0% among control subjects (p = 0.18). The mean paired difference in FMD between subjects with recent acute stroke and controls was 1.25% (95% CI -0.65, 3.14; p = 0.18). Endothelium independent dilatation was measured in six pairs of participants and was similar in acute stroke/TIA patients (22.6 ± 4.3%) and control subjects (19.1 ± 2.6%; p = 0.43).

Conclusions

Despite the small size of this study, these data indicate that recent acute stroke is not necessarily associated with a clinically important reduction in FMD.

Is endothelial dysfunction of cerebral small vessel responsible for white matter lesions after chronic cerebral hypoperfusion in rats?

Cerebral white matter (WM) lesions contribute to cognitive impairment and motor dysfunction in the elderly. Intercellular adhesion molecule-1 (ICAM-1) and vascular cell adhesion molecule-1 (VCAM-1) are two important adhesion molecules that are upregulated during endothelial activation. Data from recent studies have suggested that ICAM-1 levels are related to progression of white matter hyperintensities (WMH) on MRI. In the present study, we hypothesized that ICAM-1 and VCAM-1 are involved in the endothelial dysfunction and the subsequent WM lesions after chronic cerebral hypoperfusion. Rats underwent bilateral common carotid artery ligation. They were divided into the lipoic acid group and the saline (vehicle) group. RT-PCR and double immunofluorescence for ICAM-1, VCAM-1, endothelial cells (staining positive for von Willebrand factor, vWF), reactive astrocytes (GFAP staining) and activated microglia/macrophages/(CD11b/c staining) were analyzed at baseline and at 1, 3, 7, 14 and 28 days after hypoperfusion. The severity of the WM lesions in the corpus callosum, internal capsule, and external capsule of both hemispheres was graded by luxol fast blue staining. RT-PCR and double immunofluorescence analysis of white matter from rats that had received lipoic acid (100mg/kg/day) for 28 days exhibited markedly reduced expression of ICAM-1 and VCAM-1 over endothelial cells compared with that of rats receiving saline. In the rats treated with lipoic acid, the WM lesions after chronic cerebral hypoperfusion were significantly less severe, and the number of reactive astrocytes and activated microglia/macrophages (CD11b/c staining) were also significantly lower as compared with the saline-treated rats. These findings indicate that endothelial dysfunction plays a critical role in overexpression of ICAM-1 and VCAM-1, glial cell activation and WM lesions after chronic cerebral hypoperfusion and suggest the potential value of lipoic acid as a therapeutic tool in cerebrovascular WM lesions. Our results also provide support for endothelial activation being involved in early pathogenesis of WM lesions and suggest that therapies that stabilize the endothelium may have a role in preventing WM lesions progression.

Longitudinal trajectories of cognitive decline among older adults with cardiovascular disease

BACKGROUND

The long-term course of cognitive impairments secondary to cardiovascular disease (CVD) is unclear. In this study, we prospectively investigated the temporal pattern, rate and hierarchy of cognitive decline attributable to CVD--a risk factor for the development of vascular cognitive impairment (VCI)--and examined the influence of cardiac surgery and heart failure on cognitive decline.

METHODS

A total of 172 older adults with CVD were administered a comprehensive battery of neuropsychological tests at study entry, and at 12 and 36 months thereafter. Random coefficient regressions were used to investigate the temporal course, rate and hierarchy of cognitive decline, as well as to examine the effect of heart failure (reported by 21% of the sample) and cardiac surgery (reported by 44% of the sample) on trajectories of cognitive change.

RESULTS

The course of decline in cognition was linear for language and attention-executive function-psychomotor speed, and curvilinear for visuospatial abilities, memory and overall cognition. The decline in attention-executive function-psychomotor speed was smaller than the decline in other domains. The greatest decline occurred in visuospatial abilities. The rate of decline in cognition was not altered by a history of heart failure. Patients who had undergone cardiac surgery exhibited slower deceleration in their rates of decline in overall cognition. At baseline, patients with a history of heart failure had comparatively poorer attention-executive function-psychomotor speed, overall cognition and, to a lesser extent, visuospatial scores.

CONCLUSION

There is measurable decline in neurocognitive function among patients with CVD. This decline is linear in some cognitive domains and curvilinear in others and is not attributable to the normal aging process. Cardiac surgery, but not heart failure, significantly affects the trajectory of cognitive decline. Because most vascular risk factors are modifiable, preventive measures such as lifestyle changes may be useful in retarding cognitive decline among patients with CVD, thus preventing the onset of VCI.

Cognitive profile of chronic kidney disease and hemodialysis patients without dementia

BACKGROUND/AIMS

The high risk and prevalence of dementia among patients with chronic kidney disease (CKD) and in those receiving hemodialysis (HD) may be preceded by mild cognitive impairment (MCI). We aimed to assess cognitive function in CKD and HD patients with no history of stroke or dementia, in order to identify and characterize early cognitive deficits.

METHODS

24 CKD and 27 HD male outpatients without history of cerebrovascular or neurodegenerative disease underwent comprehensive neuropsychological testing in an observational cross-sectional study. Test results were used to categorize patients into MCI subtypes.

RESULTS

All subjects scored ≥28 on the Mini-Mental State Examination. The prevalence of executive function was at least 25% in both groups and memory impairment occurred in 13% of the HD patients and 15% of those with CKD. MCI occurred in 76% of the group and HD patients showed a higher prevalence of MCI compared to CKD patients (89 vs. 63%) with a preponderance (>70%) of cases across both groups classified as non-amnestic MCI.

CONCLUSION

Predialysis CKD and HD patients have a high prevalence of MCI despite normal global cognitive function. MCI was more prevalent among the HD patients and deficits more frequently resulted in non-amnestic MCI.

Functional imaging of working memory and peripheral endothelial function in middle-aged adults

The current study examined the relationship between a prognostic indicator of vascular health, flow-mediated dilation (FMD), and working memory-related brain activation in healthy middle-aged adults. Forty-two participants underwent functional magnetic resonance imaging while completing a 2-Back working memory task. Brachial artery endothelial-dependent flow-mediated dilation (FMD) was assessed using B-mode ultrasound. The relationship between FMD and task-related brain activation in a priori regions of interest was modeled using hierarchical linear regression. Brachial FMD, was significantly related to reduced working memory-related activation in the right superior parietal lobule (beta=0.338, p=0.027), independent of age, sex, systolic blood pressure, and full scale IQ (F(5,36)=2.66, p=0.038). These data provide preliminary support for the association between a preclinical marker of endothelial dysfunction and cerebral hemodynamic alterations in healthy middle-aged adults. Considering the modifiable nature of endothelial function, additional investigations on the prognostic significance of FMD on future cognitive impairment are warranted.

Association of C-reactive protein with cognitive impairment

BACKGROUND

High-sensitivity C-reactive protein (hsCRP) is a biomarker of cardiovascular risk that is suggested to be a biomarker for cognitive impairment.

OBJECTIVE

To explore the association between hsCRP and cognitive impairment.

DESIGN

Cross-sectional analysis of a population-based community aging study.

SETTING

Northern Manhattan, New York, New York.

OTHER PARTICIPANTS

One thousand three hundred thirty-one participants from a longitudinal study of aging without dementia and with available hsCRP and neuropsychological testing data at baseline.

MAIN OUTCOME MEASURES

Four cognitive scores (memory, visuospatial, executive, and language impairment) derived from a neuropsychological battery. Cognitive impairment was defined by scores below 1.5 SDs of demographically corrected means.

RESULTS

Participants in the highest hsCRP tertile had higher adjusted odds of impaired memory (odds ratio [OR], 1.5; 95% confidence interval [CI], 1.0-2.1; P = .03) than participants in the lowest tertile. Subjects in the highest hsCRP tertile also had greater odds of visuospatial impairment (OR, 1.6; 95% CI, 1.0-2.3; P = .03). Higher hsCRP was not associated with executive or language impairment. Persons with at least 1 APOE epsilon4 allele and hsCRP in the highest tertile had the greatest odds of impaired memory (OR, 2.7; 95% CI, 1.6-4.4).

CONCLUSIONS

High hsCRP may be a marker of memory and visuospatial impairment in the elderly. The role of APOE epsilon4 requires further exploration.

Periodontitis is associated with cognitive impairment among older adults: analysis of NHANES-III

BACKGROUND

Periodontitis is ubiquitous and associated with serological evidence of exposure to periodontal organisms, systemic inflammation and vascular disease. Dementia is a major public health problem likely related to a complex interaction between genetics and diseases associated with systemic inflammation, including diabetes, smoking and stroke.

METHODS

To assess relationships between systemic exposure to periodontal pathogens and cognitive test outcomes, data were analysed from the Third National Health and Nutrition Examination Survey (NHANES-III), a nationally representative cross sectional observational study among older adults. We included 2355 participants >or=60 years who completed measures of cognition and Poryphyromonas gingivalis IgG. Using SUDAAN, logistic regression models examined the association of P gingivalis IgG with cognitive test performance.

RESULTS

Poor immediate verbal memory (<5/9 points) was prevalent in 5.7% of patients, and 6.5% overall had impaired delayed recall (<4/9); 22.1% had difficulty with serial subtractions (<5/5 trials correct). Individuals with the highest P gingivalis IgG (>119 ELISA Units (EU)) were more likely to have poor delayed verbal recall (OR 2.89, 95% CI 1.14 to 7.29) and impaired subtraction (OR 1.95, 95% CI 1.22 to 3.11) than those with the lowest (

CONCLUSION

A serological marker of periodontitis is associated with impaired delayed memory and calculation. Further exploration of relationships between oral health and cognition is warranted.

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Key Words Collapse

MESH Headings

• Age Factors
• Aged
• Cognition
• Cognition Disorders/complications
• Cognition Disorders/epidemiology
• Cross-Sectional Studies
• Female
• Humans
• Immunoglobulin G/blood
• Male
• Middle Aged
• Nutrition Surveys
• Periodontitis/complications
• Periodontitis/epidemiology
• Periodontitis/immunology
• Porphyromonas gingivalis/immunology

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Grants

• T32 NS007153 NINDS NIH HHS
• T32 NS007153-23 NINDS NIH HHS
• 5-T32-NS07153-23 NINDS NIH HHS

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Affiliation(s)

J M Noble Gertrude H Sergievsky Center, Columbia University Medical Center, New York, NY, USA.
L N Borrell
P N Papapanou
M S V Elkind
N Scarmeas
C B Wright

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Subjective cognitive complaints relate to white matter hyperintensities and future cognitive decline in patients with cardiovascular disease

OBJECTIVE

Elderly patients with cardiovascular disease (CVD) often report cognitive difficulties including reduced cognitive processing speed and attention. On cross-sectional examination, such reports relate more closely to mood than to objective measures of cognitive performance, thus questioning the validity of subjective cognitive complaints as a marker of neurodegenerative processes. This study examined the longitudinal relationship among self-reported cognitive difficulties, depression, and performance on objective tests of global cognition in patients with CVD.

PARTICIPANTS AND METHODS

Forty-seven patients with CVD (aged 55-85 years) completed a measure of perceived cognitive dysfunction (Cognitive Difficulties Scale [CDS]), a medical history questionnaire, the Dementia Rating Scale (DRS), and the Beck Depression Inventory (BDI) at baseline and 12 months later. Baseline brain imaging was available on a small subsample (N = 17).

RESULTS

Hierarchical linear regression revealed that increased report of cognitive difficulties at baseline was significantly associated with poorer DRS performance at follow-up (F[3, 43] = 4.45, p = 0.008, CDS partial r = -0.30, p = 0.048), independent of age, education, baseline DRS, and BDI scores. Greater perceived cognitive dysfunction at baseline also related to higher level of white matter lesions (r = 0.53, df = 15, p = 0.028).

CONCLUSIONS

Self-reported cognitive difficulties may reflect early changes in cognitive aging that are difficult to detect using global cognitive screening measures at a single time point. However, these perceived difficulties relate to objectively measured cognitive decline over time. Thus, they may provide important clinical information about early neurodegenerative processes that should be carefully monitored.

Circadian variation in the circulatory responses to exercise: relevance to the morning peaks in strokes and cardiac events

Sudden cardiac and cerebral events are most common in the morning. A fundamental question is whether these events are triggered by the increase in physical activity after waking, and/or a result of circadian variation in the responses of circulatory function to exercise. Although signaling pathways from the master circadian clock in the suprachiasmatic nuclei to sites of circulatory control are not yet understood, it is known that cerebral blood flow, autoregulation and cerebrovascular reactivity to changes in CO(2) are impaired in the morning and, therefore, could explain the increased risk of cerebrovascular events. Blood pressure (BP) and the rate pressure product (RPP) show marked 'morning surges' when people are studied in free-living conditions, making the rupture of a fragile atherosclerotic plaque and sudden cardiac event more likely. Since cerebral autoregulation is reduced in the morning, this surge in BP may also exacerbate the risk of hemorrhagic and ischemic strokes in the presence of other acute and chronic risk factors. Increased sympathetic activity, decreased endothelial function, and increased platelet aggregability could also be important in explaining the morning peak in cardiac and cerebral events but how these factors respond to exercise at different times of day is unclear. Evidence is emerging that the exercise-related responses of BP and RPP are increased in the morning when prior sleep is controlled. We recommend that such 'semi-constant routine' protocols are employed to examine the relative influence of the body clock and exogenous factors on the 24-h variation in other circulatory factors.

P-selectin 1087G/A polymorphism is associated with neuropsychological test performance in older adults with cardiovascular disease

BACKGROUND AND PURPOSE

There is growing evidence that the cell adhesion molecule P-selectin (SELP) contributes to the adverse vascular processes that promote cognitive impairment in individuals with cardiovascular disease. Previous research has shown that SELP genotypes moderate circulating levels of P-selectin and that patients undergoing coronary artery bypass graft with the SELP 1087A allele were less likely to show postoperative cognitive decline and more likely to exhibit lower levels of C-reactive protein than noncarriers. Thus, we expected that carriers of the 1087A allele (n=43) would exhibit better cognitive functioning than persons with 2 1087G alleles (n=77) and that C-reactive protein levels would be important for this relationship.

METHODS

One hundred twenty older adults with diagnosed cardiovascular disease were recruited from outpatient cardiology clinics. Each participant underwent a comprehensive neuropsychological test battery and a blood draw.

RESULTS

Participants with the SELP 1087A allele performed more poorly on tests of attention (Trail Making Test A: t[116]=3.20, P=0.002), executive function (Trail Making Test B: t[116]=2.89, P=0.005), psychomotor speed (Digit-Symbol Coding: t[117]=2.54, P=0.012), and memory (California Verbal Learning Test Discrimination: t[116]=2.05, P=0.04). There were no significant differences between the SELP genotype groups on demographic/medical variables or C-reactive protein levels.

CONCLUSIONS

Contrary to expectations, the present analyses showed that older patients with cardiovascular disease with the SELP 1087A allele performed more poorly on neuropsychological testing. Findings from the present study were counter to previous research with coronary artery bypass graft candidates. Further work using neuroimaging and alternative measures of cardiovascular function is needed to clarify the mechanisms of this association.

A fMRI Study of Verbal Working Memory, Cardiac Output, and Ejection Fraction in Elderly Patients with Cardiovascular Disease

Cardiovascular disease (CVD) is associated with cognitive deficits even in the absence of stroke. We examined the relationship between cardiac performance, as measured by cardiac output (CO) and ejection fraction (EF), and brain activity during a verbal working memory (VWM) task in elderly CVD patients who tend to be at increased risk for vascular cognitive impairments. Seventeen patients were recruited from a cohort participating in an ongoing prospective study examining the effects of CVD on cognitive function in the elderly. Participants were diagnosed with CVD (age 68±8) and completed a 2-back VWM task in a 1.5T fMRI paradigm. CO and EF were calculated from echocardiogram measures. Task-related activation was averaged in a priori regions of interest. The relationship between CO, EF, and 2-back-related activity was modeled using partial correlations (two-tailed p<.05) controlling for age and 2-back accuracy. All participants were globally cognitively intact as indicated by Mini-Mental Status Exam and Dementia Rating Scale scores. Mean accuracy on the 2-back was 78±9% while reaction time averaged 1,027±192 ms. Mean CO and EF values showed a large range (CO: 3.55 to 6.31; EF: 0.36 to 0.76) but average values were within the normal range. After controlling for age and 2-back accuracy, lower EF was related to decrease in left insula activity (r=0.61, p=0.03). There were trends for EF to be related to accuracy (r=0.47, p=0.09) and reaction time (r=-0.48, p=0.09). CO was also related to insula activity (r=0.60, p=0.04) and activity in the supplementary motor area activity (r=0.66, p=0.01). Cardiac performance was related to decreased efficiency in task related brain areas and tended to be related to performance on a VWM task in elderly patients with CVD. Results have implications for a line of investigation indicating that cardiac and systemic vascular indices could be used as proxy measures to examine mechanisms of cerebrovascular dysfunction in the elderly.

Vascular structure and function is correlated to cognitive performance and white matter hyperintensities in older hypertensive patients with subjective memory complaints

BACKGROUND AND PURPOSE

Arterial stiffening and thickening and endothelial dysfunction may be associated with cognitive decline or white matter hyperintensities (WMH) independently of blood pressure level. We aimed to investigate, using an integrative approach, the relative contributions of structural and functional vascular factors to the degree of cognitive impairment (primary outcome) and the severity of WMH (secondary outcome) in elderly hypertensive patients with subjective memory complaints, a group prone to dementia.

METHODS

A prospective, dedicated, cross-sectional population of 198 elderly hypertensive patients (mean age 69.3+/-6.2 years) with subjective memory complaints underwent a full set of cognitive function assessments, brain MRI with semiquantification of WMH, carotid ultrasonography, carotid-femoral pulse wave velocity, brachial endothelial function, and plasma von Willebrand Factor measurements.

RESULTS

After adjustment for the usual cardiovascular risk factors, increased arterial stiffness (as assessed by pulse wave velocity) was significantly and independently associated with memory impairment in men. The severity of WMH was independently associated with increased carotid intima media thickness and stiffness (as assessed by augmentation index) as well as with increased age and plasma levels of von Willebrand Factor, a biomarker of endothelial dysfunction.

CONCLUSIONS

Our data suggest that vascular abnormalities, independently of blood pressure levels, may play a role in the setting of subjective memory complaints as well as of WMH in elderly hypertensive patients. Arterial thickness and stiffness as well as endothelial function should be assessed simultaneously and may represent additional targets for the prevention of subjective memory complaints and WMH.