The Erythrosense as a Real-Time Biomarker to Reveal the Presence of Enhanced Red Blood Cell Aggregability in Atherothrombosis

Associations between cardiometabolic multimorbidity and cerebrospinal fluid biomarkers of Alzheimer's disease pathology in cognitively intact adults: the CABLE study

BACKGROUND

Cardiometabolic multimorbidity is associated with an increased risk of dementia, but the pathogenic mechanisms linking them remain largely undefined. We aimed to assess the associations of cardiometabolic multimorbidity with cerebrospinal fluid (CSF) biomarkers of Alzheimer's disease (AD) pathology to enhance our understanding of the underlying mechanisms linking cardiometabolic multimorbidity and AD.

METHODS

This study included 1464 cognitively intact participants from the Chinese Alzheimer's Biomarker and LifestylE (CABLE) database. Cardiometabolic diseases (CMD) are a group of interrelated disorders such as hypertension, diabetes, heart diseases (HD), and stroke. Based on the CMD status, participants were categorized as CMD-free, single CMD, or CMD multimorbidity. CMD multimorbidity is defined as the coexistence of two or more CMDs. The associations of cardiometabolic multimorbidity and CSF biomarkers were examined using multivariable linear regression models with demographic characteristics, the APOE ε4 allele, and lifestyle factors as covariates. Subgroup analyses stratified by age, sex, and APOE ε4 status were also performed.

RESULTS

A total of 1464 individuals (mean age, 61.80 years; age range, 40-89 years) were included. The markers of phosphorylated tau-related processes (CSF P-tau181: β = 0.165, P = 0.037) and neuronal injury (CSF T-tau: β = 0.065, P = 0.033) were significantly increased in subjects with CMD multimorbidity (versus CMD-free), but not in those with single CMD. The association between CMD multimorbidity with CSF T-tau levels remained significant after controlling for Aβ42 levels. Additionally, significantly elevated tau-related biomarkers were observed in patients with specific CMD combinations (i.e., hypertension and diabetes, hypertension and HD), especially in long disease courses.

CONCLUSIONS

The presence of cardiometabolic multimorbidity was associated with tau phosphorylation and neuronal injury in cognitively normal populations. CMD multimorbidity might be a potential independent target to alleviate tau-related pathologies that can cause cognitive impairment.

Cognition and drug adherence to oral hypoglycemic and antihypertensive agents in older adults

Background and objectives: Chronic disorders such as diabetes mellitus type II and hypertension have been associated with cognitive decline in older adults. It is unclear whether adherence to antihypertensive and oral hypoglycemic agents impact cognitive health. The objectives are to study the association between adherence to antihypertensive and oral hypoglycemic agents and cognitive status in community-living older adults. Methods: We used data from a large representative sample of older adults (N=2,286) covered under a public drug insurance plan in Quebec and participating in Quebec's health survey on older adults (ESA-study) with a Mini-Mental State Examination (MMSE) score ≥22 at baseline (T1) and examined one year later (T2). Participants with hypertension and diabetes mellitus type II were identified according to criteria used in the Canadian Chronic Disease Surveillance System. Antihypertensive and oral hypoglycemic prescriptions delivered were ascertained via Quebec's pharmaceutical database (RAMQ). Medication adherence was calculated using the medication possession ratio as a continuous variable in the year prior to and following baseline interview. Multivariate linear regressions were used to study the percentage change in MMSE scores between interviews (T1,T2) as a function of adherence to antihypertensive and oral hypoglycemic agents (before and after T1) controlling for potential confounders. Results: In participants with diabetes mellitus type II only, adherence to oral hypoglycemics was not associated with a change in MMSE scores. In participants with hypertension only, the change in MMSE scores was associated with adherence to antihypertensives (β 1.23; 95%CI: 0.29-2.17). In participants with comorbid hypertension and diabetes mellitus type II, the change in MMSE scores was associated with adherence to both antihypertensive and oral hypoglycemic agents (β 0.75; 95%CI: 0.01-1.48). Conclusions: Adherence to oral hypoglycemic agents and antihypertensive agents among older adults with hypertension and comorbid diabetes mellitus type II can have a preserving effect on cognitive health in older adults. Further research on the long-term impact on cognition is recommended.

Sex and Age Differences in the Association of Blood Pressure and Hypertension with Cognitive Function in the Elderly: The Rancho Bernardo Study

OBJECTIVES

This study examines sex and age differences in associations of systolic and diastolic blood pressure (SBP, DBP), pulse pressure and hypertension with cognitive function in a community-dwelling population.

DESIGN

Cross-sectional study.

SETTING

Research clinic visit in 1988-91.

PARTICIPANTS

Participants were 693 men and 1022 women aged 50-97 Measurements: Blood pressure was measured and 12 cognitive function tests were administered.

RESULTS

Average age was 73.8±9.9 in men and 73.2±9.3 in women; 62.6% of men and 63.4% of women were hypertensive (SBP≥140 mmHg, DBP≥90 mmHg, or antihypertensive medication use). Each 5-unit increment in SBP, DBP, or pulse pressure and categorical hypertension was associated with significantly increased odds of poor verbal fluency performance in men and poor Trails B performance in women, with strongest associations for hypertension (OR=1.97, CI:1.01,3.85 in men; OR=1.51, CI:1.01,2.26 in women). After age stratification, associations remained statistically significant in younger (<80 years ) but not older (≥80 years) participants.

CONCLUSION

Blood pressure as a continuous or categorical variable was associated with poor performance on cognitive function tests, but domains varied by sex and associations were found only in those younger than 80 years. The absent associations in those aged 80 years and older could support the hypothesis that increased blood flow is required to maintain cerebral perfusion with advancing age, or could reflect a survivor effect.

Brain Oscillations Elicited by the Cold Pressor Test: A Putative Index of Untreated Essential Hypertension

Objective

Essential hypertension is associated with reduced pain sensitivity of unclear aetiology. This study explores this issue using the Cold Pressor Test (CPT), a reliable pain/stress model, comparing CPT-related EEG activity in first episode hypertensives and controls.

Method

22 untreated hypertensives and 18 matched normotensives underwent 24-hour ambulatory blood pressure monitoring (ABPM). EEG recordings were taken before, during, and after CPT exposure.

Results

Significant group differences in CPT-induced EEG oscillations were covaried with the most robust cardiovascular differentiators by means of a Canonical Analysis. Positive correlations were noted between ABPM variables and Delta (1–4 Hz) oscillations during the tolerance phase; in high-alpha (10–12 Hz) oscillations during the stress unit and posttest phase; and in low-alpha (8–10 Hz) oscillations during CPT phases overall. Negative correlations were found between ABPM variables and Beta2 oscillations (16.5–20 Hz) during the posttest phase and Gamma (28.5–45 Hz) oscillations during the CPT phases overall. These relationships were localised at several sites across the cerebral hemispheres with predominance in the right hemisphere and left frontal lobe.

Conclusions

These findings provide a starting point for increasing our understanding of the complex relationships between cerebral activation and cardiovascular functioning involved in regulating blood pressure changes.

No Evidence of Causal Effects of Blood Pressure on Cognition in the Population at Large

The large body of literature on the association between blood pressure (BP) and cognitive functioning has yielded mixed results, possibly due to the presence of non-linear effects across age, or because BP affects specific brain areas differently, impacting more on some cognitive skills than on others. If a robust association was detected among BP and specific cognitive tasks, the causal nature of reported associations between BP and cognition could be investigated in twin data, which allow a test of alternative explanations, including genetic pleiotropy. The present study first examines the association between BP and cognition in a sample of 1,140 participants with an age range between 10 and 86 years. Linear and quadratic effects of systolic BP (SBP) and diastolic BP (DBP) on cognitive functioning were examined for 17 tests across five functions. Associations were corrected for effects of sex and linear and quadratic effects of age. Second, to test a causal model, data from 123 monozygotic (MZ) twin pairs were analyzed to test whether cognitive functioning of the twins with the higher BP was different from that of the co-twins with lower BP. Associations between BP and cognitive functioning were absent for the majority of the cognitive tests, with the exception of a lower speed of emotion identification and verbal reasoning in subjects with high diastolic BP. In the MZ twin pair analyses, no effects of BP on cognition were found. We conclude that in the population at large, BP level is not associated with cognitive functioning in a clinically meaningful way.

Hypertension is associated with cognitive decline in elderly people at high risk for dementia

Cardiovascular risk factors including hypertension (HTN) have been shown to increase the risk of Alzheimer disease. The current study investigated whether individuals with HTN are more susceptible to increased cognitive decline and whether the influence of HTN on cognitive decline varied as a function of dementia severity. A total of 224 nursing home and assisted living residents, with a mean age of 84.9 (±7.6) years, were assessed longitudinally with Mini Mental State Exams (MMSEs) and Clinical Dementia Ratings (CDR). Baseline dementia status was defined by the CDR score. As described in , MMSE scores in persons with HTN and questionable dementia (CDR = 0.5) declined significantly faster than nonhypertensive questionably demented persons. Hypertensive participants did not decline significantly faster than nonhypertensive participants in persons with intact cognition (CDR = 0) or frank dementia (CDR ≥ 1). These results suggest an increased risk of subsequent cognitive decline in hypertensive individuals who are especially vulnerable to developing dementia and raises the possibility that avoiding or controlling HTN might reduce the rate of cognitive decline in cognitively vulnerable individuals, potentially delaying their conversion to full-fledged dementia.

Association between white matter microstructure, executive functions, and processing speed in older adults: the impact of vascular health

Cerebral white matter damage is not only a commonly reported consequence of healthy aging, but is also associated with cognitive decline and dementia. The aetiology of this damage is unclear; however, individuals with hypertension have a greater burden of white matter signal abnormalities (WMSA) on MR imaging than those without hypertension. It is therefore possible that elevated blood pressure (BP) impacts white matter tissue structure which in turn has a negative impact on cognition. However, little information exists about whether vascular health indexed by BP mediates the relationship between cognition and white matter tissue structure. We used diffusion tensor imaging to examine the impact of vascular health on regional associations between white matter integrity and cognition in healthy older adults spanning the normotensive to moderate-severe hypertensive BP range (43-87 years; N = 128). We examined how white matter structure was associated with performance on tests of two cognitive domains, executive functioning (EF) and processing speed (PS), and how patterns of regional associations were modified by BP and WMSA. Multiple linear regression and structural equation models demonstrated associations between tissue structure, EF and PS in frontal, temporal, parietal, and occipital white matter regions. Radial diffusivity was more prominently associated with performance than axial diffusivity. BP only minimally influenced the relationship between white matter integrity, EF and PS. However, WMSA volume had a major impact on neurocognitive associations. This suggests that, although BP and WMSA are causally related, these differential metrics of vascular health may act via independent pathways to influence brain structure, EF and PS.

Program of rehabilitative exercise and education to avert vascular events after non-disabling stroke or transient ischemic attack (PREVENT Trial): a multi-centred, randomised controlled trial

BACKGROUND

Despite lack of outward signs, most individuals after non-disabling stroke (NDS) and transient ischemic attack (TIA) have significant cardiovascular and cerebrovascular disease and are at high risk of a major stroke, hospitalization for other vascular events, or death. Most have multiple modifiable risk factors (e.g., hypertension, physical inactivity, hyperlipidaemia, diabetes, tobacco consumption, psychological stress). In addition, accelerated rates of depression, cognitive decline, and poor quality of sleep have been reported following TIA, which correlate with poor functional outcomes and reduced quality of life. Thus, NSD and TIA are important warning signs that should not be overlooked. The challenge is not unlike that facing other 'silent' conditions - to identify a model of care that is effective in changing people's current behaviors in order to avert further morbidity.

METHODS/DESIGN

A single blind, randomized controlled trial will be conducted at two sites to compare the effectiveness of a program of rehabilitative exercise and education versus usual care in modifying vascular risk factors in adults after NDS/TIA. 250 adults within 90 days of being diagnosed with NDS/TIA will be randomly allocated to a 12-week program of exercise and education (PREVENT) or to an outpatient clinic assessment and discussion of secondary prevention recommendations with return clinic visits as indicated (USUAL CARE). Primary outcome measures will include blood pressure, waist circumference, 12-hour fasting lipid profile, and 12-hour fasting glucose/hemoglobin A1c. Secondary measures will include exercise capacity, walking endurance, physical activity, cognitive function, depression, goal attainment and health-related quality of life. Outcome assessment will be conducted at baseline, post-intervention, and 6- and 12-month follow-ups. Direct health care costs incurred over one year by PREVENT versus USUAL CARE participants will also be compared. Ethical approval for the trial has been obtained from the relevant Human Research Ethics Boards.

DISCUSSION

Whether timely delivery of an adapted cardiac rehabilitation model is effective in attaining and maintaining vascular risk reduction targets in adults after NDS/TIA is not yet known. We anticipate that the findings of this trial will make a meaningful contribution to the knowledge base regarding secondary stroke prevention.

Cognitive function and antihypertensive treatment in the elderly: a 6-year follow-up study

Both antihypertensive treatment and statins were proved to reduce mortality and morbidity from cardiovascular disease in the elderly. Yet their effect on cognitive functions of the elderly is unclear. In this study, 518 elderly were interviewed at their home six years ago. BP was measured and antihypertensive drug treatment and cognitive functions were evaluated. 318 of the original sample were re-examined (81% of the survivors). We evaluated the selective survival in relation to changes in BP, the specific drug usage and cognitive functioning. Beta blocker treatment increased the odds of survival but also the odds of decline in MMSE and memory scores. ACE-I treatment was also associated with decline in memory. Subjects treated with CCB had improved MMSE scores, memory, and performed better on tasks requiring concentration. Statins treatment in this study did not show any affect on cognitive functions. Although most subjects were treated by more than one antihypertensive drug, less than half were normalized at baseline and only one quarter at follow-up. Despite the low normalization rate, antihypertensive treatment regimen had been hardly changed during the six years follow-up. The use of statins, however, increased dramatically: from 6% at baseline to almost half at follow-up. According to our findings CCB emerges as the best option for reducing BP in elderly patients. It appeared to improve cognitive functions without hampering survival.

Association between white matter hyperintensities and executive decline in mild cognitive impairment is network dependent

White matter hyperintensities (WMH) in Mild Cognitive Impairment (MCI) have been associated with impaired executive functioning, although contradictory findings have been reported. The aim of this study was to examine whether WMH location influenced the relation between WMH and executive functioning in MCI participants (55-90 years) in the European multicenter memory-clinic-based DESCRIPA study, who underwent MRI scanning at baseline (N = 337). Linear mixed model analysis was performed to test the association between WMH damage in three networks (frontal-parietal, frontal-subcortical and frontal-parietal-subcortical network) and change in executive functioning over a 3-year period. WMH in the frontal-parietal and in the frontal-parietal-subcortical network were associated with decline in executive functioning. However, the frontal-subcortical network was not associated with change in executive functioning. Our results suggest that parietal WMH are a significant contributor to executive decline in MCI and that investigation of WMH in the cerebral networks supporting cognitive functions provide a new way to differentiate stable from cognitive declining MCI individuals.

Cognitive impairment and hypertension among Chinese nonagenarians and centenarians

In this study, we explore the association between hypertension and cognitive impairment in the very elderly, using a sample ranging in age from 90 to 108 years. This work was conducted as a cross-sectional study. Our population included 782 unrelated Chinese nonagenarians and centenarians (67.5% women, mean age 93.62 years). The mean cognitive function score for the sample was 14.95 (s.d.: 5.99, range: 0-28). There were no significant differences between individuals with and without hypertension with regard to cognitive function scores (14.95+/-6.01 vs. 14.95+/-5.82, P=0.997) or cognitive impairment prevalence (59.52 vs. 59.42, P=0.976). There were also no significant differences in the prevalence of hypertension (56.99 vs. 57.10, P=0.976) or in the levels of arterial blood pressure (including systolic blood pressure (SBP) and diastolic blood pressure (DBP)) (139.86+/-22.69 vs. 140.28+/-23.51, P=0.799 and 73.05+/-12.07 vs. 72.11+/-12.06, P=0.678, for SBP and DBP, respectively) between individuals with and without cognitive impairment. Multiple logistic regression showed that cognitive impairment and hypertension were not risk factors for each other (odds ratio (OR) of cognitive impairment as a function of increased hypertension: 0.938 (0.655, 1.341); OR of hypertension as a function of increased cognitive impairment: 0.920 (0.643, 1.317)). In summary, we found that cognitive impairment was not directly correlated with hypertension among Chinese nonagenarians and centenarians.

Less Alzheimer disease neuropathology in medicated hypertensive than nonhypertensive persons

OBJECTIVE

To test the hypothesis that use of antihypertensive medication is associated with lower Alzheimer disease (AD) neuropathology.

METHODS

This was a postmortem study of 291 brains limited to those with normal neuropathology or with uncomplicated AD neuropathology (i.e., without other dementia-associated neuropathology) in persons with or without hypertension (HTN) who were and were not treated with antihypertensive medications. Neuritic plaque (NP) and neurofibrillary tangle (NFT) densities, quantified in selected brain regions according to the Consortium to Establish a Registry for Alzheimer's Disease (CERAD) neuropathologic criteria, with additional cortical NP counts, yielded 24 neuropathologic regional measures or summaries. Medicated hypertension (HTN-med; n = 77), nonmedicated HTN (HTN-nomed; n = 42), and non-HTN (no-HTN; n = 172) groups were compared by analyses of variance.

RESULTS

The HTN-med group had significantly less neuropathology than the no-HTN group. The no-HTN group averaged over 50% higher mean NP and NFT ratings, and double the mean NP count, of the HTN-med group. The HTN-nomed group had significantly more neuropathology than the HTN-med group, but not significantly less than the no-HTN group.

CONCLUSIONS

There was substantially less Alzheimer disease (AD) neuropathology in the medicated hypertension group than the nonhypertensive group, which may reflect a salutary effect of antihypertensive medication against AD-associated neuropathology.

Management of hypertension and cerebrovascular disease in the elderly

Cardiovascular disease and stroke disproportionately affect the elderly. The risk for stroke and transient ischemic attack increases exponentially with age. Blood pressure is a potent modifiable target for reducing the risk for stroke in the elderly. In elderly patients with isolated systolic hypertension and those with intracranial atherosclerotic disease, blood pressure lowering has consistently been shown to be well tolerated and effective in reducing the risk for stroke and its complications. Evidence suggests that ambulatory blood pressure monitoring may provide a more sensitive means of detecting patients at risk and monitoring therapeutic effect. Agents that modify the renin-angiotensin system, particularly angiotensin receptor blockers, may confer additional benefit in stroke protection beyond blood pressure lowering. Several clinical trials currently in progress promise to provide guidance regarding the optimal choice of agent and degree of blood pressure lowering for prevention of stroke and cognitive decline in elderly patients.

Blood pressure is associated with cognitive impairment in young hypertensives

AIMS

The present study was conducted to assess the effects of duration of hypertension, systolic hypertension, diastolic hypertension, drug compliance and class-of-drug on cognitive functions.

METHODS AND RESULTS

A cohort of young hypertensive subjects was recruited after obtaining informed consent. Subjects with confounding factors, e.g., substance use, neurological disorders, endocrinopathies, inflammatory conditions, psychiatric illnesses, etc., were excluded. Their average systolic and diastolic blood pressure since onset of illness and prescribed drugs were noted from the records. Compliance was assessed with the help of information from subjects as well as the close relatives. MMSE and a battery of neuropsychological tests (Digit Span Test, Trail Making Test Form B, Stroop Test, Visuospatial Working Memory Matrix and Word Fluency Test) was applied to all the participants. Multivariate regression analysis was used for the assessment of associations and one-way ANOVA was performed to assess differences in the mean. Analysis showed that mean age of study subject was 52 years and average duration of hypertension was 9 years. Fourteen percent subjects had obvious cognitive impairment as suggested by MMSE score less than 23. However, when cut-off score was lowered to 20, only 6% subjects fell into this category. Diastolic blood pressure had significant negative association with all of the cognitive measures except Trail Making Test, which was, on the contrary, significantly and negatively associated with systolic blood pressure. Duration of hypertension did not influence cognitive performance in this study. Effect of drug compliance was somewhat variable, but in general good compliance was associated with better cognitive performance. Beta-Blocker therapy hampered cognitive performance, whereas the best performance, especially on tests of semantic memory and pre-frontal functions was seen in subjects taking calcium channel blockers.

CONCLUSIONS

Diastolic hypertension was associated with significant impairment of cognitive functions in younger subjects. On the other hand good compliance and calcium channel blockers had protective effect on hypertension induced cognitive impairment, especially on the prefrontal functions.

Hypertension, vascular cognitive disorders and neuroprotection

OBJECTIVE

The role of the antihypertensive therapy in preventing vascular cognitive disorders in elderly persons without a history of stroke is a matter of debate. This review focuses on cognitive disorders in elderly hypertensive patients.

METHODS

Relevant papers were identified by searches in PubMed from 1946 until February 2007 using the keywords 'cerebral blood flow autoregulation', 'vascular cognitive disorders', 'neuroimaging in hypertension', 'antihypertensive treatment' and 'neuroprotection in cerebral ischemia'.

RESULTS

Excessive blood pressure lowering in patients with long-standing hypertension may increase the risk of cerebral hypoperfusion, white matter lesions and consequent cognitive decline. White matter lesions have been found in the majority of patients with long-standing hypertension. They correlate with vascular cognitive disorders, particularly impairments of attention and executive function, while memory is relatively preserved. Cerebral small vessel disease in elderly patients should be taken into account when antihypertensive treatment is considered. Renin-angiotensin blockade, some calcium channel blockers and statins are thought to possess neuroprotective action.

CONCLUSION

For prevention of cerebral hypoperfusion in elderly hypertensives blood pressure lowering should be cautiously controlled. The increased risk of white matter lesions is an indication for early neuroprotection. The combination of renin-angiotensin blockade or calcium channel blockers with statins may become a promising preventive strategy against cognitive decline in elderly hypertensives. Cerebral white matter protection is a future challenge.

Clinical pharmacology in the geriatric patient

Geriatric patients are a subset of older people with multiple comorbidities that usually have significant functional implications. Geriatric patients have impaired homeostasis and wide inter-individual variability. Comprehensive geriatric assessment captures the complexity of the problems that characterize frail older patients and can be used to guide management, including prescribing. Prescribing for geriatric patients requires an understanding of the efficacy of the medication in frail older people, assessment of the risk of adverse drug events, discussion of the harm:benefit ratio with the patient, a decision about the dose regime and careful monitoring of the patient's response. This requires evaluation of evidence from clinical trials, application of the evidence to frail older people through an understanding of changes in pharmacokinetics and pharmacodynamics, and attention to medication management issues. Given that most disease occurs in older people, and that older people are the major recipients of drug therapy in the Western world, increased research and a better evidence base is essential to guide clinicians who manage geriatric patients.

The effects of blood pressure reduction on cognitive function: a review of effects based on pooled data from clinical trials

OBJECTIVE

To review systematically and synthesize quantitatively the evidence from completed randomized, controlled trials of blood pressure reduction on cognitive performance.

METHODS

MEDLINE, EMBASE and Cochrane databases were searched to identify randomized, controlled trials that measured the effect of blood pressure reduction on cognitive performance. Additional studies were identified by searching bibliographies of retrieved articles and contacting experts in the field. Data were extracted on study quality, blood pressure, performance on cognitive function tests, antihypertensive treatment regimens and the duration of treatment. Studies were reviewed and abstracted independently by two trained researchers.

RESULTS

Sixteen studies with 19 501 subjects were identified. Modest reductions in blood pressure (< 5/3 mmHg) in 13 860 subjects were associated with improvements in Mini Mental State Examination score [weighted mean difference (WMD) = 0.19; 95% confidence interval (CI) = 0.19-0.19] and performance on immediate (WMD = 0.62; 95% CI = 0.21-1.02) and delayed (WMD = 0.67; 95% CI = 0.23-1.11) logical memory tasks. However, studies in 2380 subjects that included tests of perceptual processing and learning capacity (trail making test-A, paired associated learning test) showed impaired performance (WMD = -1.12 s; 95% CI = -1.22 to -1.02 and WMD = -0.04; 95% CI = -0.04 to -0.04) on these tests.

CONCLUSION

Blood pressure lowering may have a heterogeneous effect on different aspects of cognitive function. Future studies with specific cognitive end-points are needed for greater clarity to guide practice.