Renin-angiotensin system blockade and cognitive function in patients at high risk of cardiovascular disease: analysis of data from the ONTARGET and TRANSCEND studies

Blood pressure-lowering interventions to prevent dementia: a systematic review and meta-analysis

: Our objective was to study the preventive effect of lowering blood pressure (BP) by medication and/or lifestyle changes on incident all-cause dementia, Alzheimer's disease and vascular dementia. In this systematic review, we included randomized controlled trials with a BP-lowering intervention. Of the nine included trials, seven assessed the effect of antihypertensive medication and two of a lifestyle or combined intervention. In the intervention arm, 1041 out of 29 029 (3.6%) participants were diagnosed with dementia compared with 1090 out of 28 653 (3.8%) controls during a median follow-up of 3.9 years [range 2-10], resulting in a pooled risk ratio of 0.93 (95% confidence interval 0.84-1.02; I 16%). Three trials specified dementia subtypes, with no significant effect on Alzheimer's disease or vascular dementia. To conclude, lowering BP by medication and/or lifestyle changes did not lead to a significantly reduced risk of dementia. This appeared independent of dementia subtype.

Associations of Angiotensin Converting Enzyme-1 and Angiotensin II Blood Levels and Cognitive Function

BACKGROUND

Emerging evidence suggests a possible role of the renin angiotensin system in the pathophysiologic process of Alzheimer's disease, of which angiotensin converting enzyme-1 (ACE-1) and angiotensin II (ANGII) are important proteins. Few studies evaluated associations between blood ACE-1 and none between ANGII levels, and cognition.

OBJECTIVE

Our pilot study was aimed to examine associations between blood ACE-1 and ANG II levels and cognitive function in non-demented participants at baseline and over a 1-year period.

METHODS

56 participants were included from the Brain Health Substudy of the Baltimore Experience Corps Study. Linear regression analysis, adjusting for confounders, was used to determine associations between baseline ACE-1 and ANGII, and baseline and 1-year follow-up measures of psychomotor and processing speed, executive function, verbal learning memory and working memory, and whether these associations were mediated by blood pressure.

RESULTS

Participants were predominantly female (75%), African-American (93%), with mean age of 67.8 years and education of 14.3 years. There were no associations between baseline ACE-1 or ANGII levels and cognitive function; however, there were significant association between baseline ACE-1 levels and 1-year follow-up Trail Making Test, Part A (β= 0.003, p = 0.04) and Digit Span (β= -0.001, p = 0.02).

CONCLUSIONS

In this cognitively intact sample, elevated ACE-1 levels were associated with worse processing speed and working memory after 1 year. Findings from this pilot study suggest that changes in the RAS are associated with alterations in cognitive function warranting further assessment of the role of RAS in neurodegenerative disorders.

Efficacy and safety of leuprorelin acetate for subjects with spinal and bulbar muscular atrophy: pooled analyses of two randomized-controlled trials

BACKGROUND

Spinal and bulbar muscular atrophy (SBMA) is an adult-onset, hereditary neuromuscular disease characterized by muscle atrophy, weakness, contraction fasciculation, and bulbar involvement. Although the causative gene, androgen receptor, has been identified, the development of novel therapeutics for SBMA is incomplete. In this study, the efficacy and safety of leuprorelin acetate administration for patients with SBMA, using the pooled data of two randomized-controlled trials, was studied.

METHODS

Two randomized double-blinded studies (JASMITT-06DB and JASMITT-11DB) were done as multicentric, investigator-initiated clinical trials in Japan. In both studies, eligible patients were randomly assigned 1:1 to receive leuprorelin acetate administration once per 12 weeks for 48 weeks. The primary endpoint was the longitudinal change of pharyngeal barium residues from the baseline data measured with videofluorographic swallowing analyses. The pooled analysis plan was decided upon after the 06B study was finished and before the 11DB study began.

RESULTS

The primary endpoint difference between the leuprorelin group and the placebo group was pharyngeal barium residue after initial swallowing, - 4.12% (95% CI, - 8.40-0.15; p = 0.058). The primary endpoint of this study does not reach significant results, although inter-group differences of pharyngeal barium residues after the initial swallowing indicated that leuprorelin acetate may be effective at each assessment point in both study groups.

CONCLUSIONS

The efficacy of leuprorelin acetate for patients with SBMA was statistically similar in two randomized-controlled trials, and suggested that leuprorelin acetate may be effective and safe. Further investigations are needed to clarify the promising efficacy of the drug.

Augmentation of Extinction and Inhibitory Learning in Anxiety and Trauma-Related Disorders

Although the fear response is an adaptive response to threatening situations, a number of psychiatric disorders feature prominent fear-related symptoms caused, in part, by failures of extinction and inhibitory learning. The translational nature of fear conditioning paradigms has enabled us to develop a nuanced understanding of extinction and inhibitory learning based on the molecular substrates to systems neural circuitry and psychological mechanisms. This knowledge has facilitated the development of novel interventions that may augment extinction and inhibitory learning. These interventions include nonpharmacological techniques, such as behavioral methods to implement during psychotherapy, as well as device-based stimulation techniques that enhance or reduce activity in different regions of the brain. There is also emerging support for a number of psychopharmacological interventions that may augment extinction and inhibitory learning specifically if administered in conjunction with exposure-based psychotherapy. This growing body of research may offer promising novel techniques to address debilitating transdiagnostic fear-related symptoms.

Neurofibrillary Tangles and Conversion to Mild Cognitive Impairment with Certain Antihypertensives

BACKGROUND

Individuals taking renin angiotensin system (RAS) acting antihypertensives exhibit slower cognitive decline and are less likely to progress from mild cognitive impairment (MCI) to Alzheimer's disease (AD), but the mechanism remains unclear.

OBJECTIVE

We tested the hypothesis that individuals taking RAS acting antihypertensives exhibit less AD-related neuropathology and slower disease progression than individuals taking non-RAS acting antihypertensives.

METHOD

Participants included 83 individuals with MCI who were taking an antihypertensive at baseline, had at least two follow-up visits, and had postmortem neuropathological data. Participants were old (M = 83.1 years), 32% male, well educated (M = 15.7 years), and 9.2% Black.

RESULTS

RAS medication users (N = 38) were less likely to progress to AD than non-RAS users (N = 45). RAS users exhibited fewer neurofibrillary tangles than non-RAS users in the hippocampal CA1 region (p < 0.01), entorhinal cortex (p = 0.03), and the angular gyrus, inferior temporal, mid-frontal cortex, and superior frontal (p = 0.01).

CONCLUSION

Prevention or clearance of neurofibrillary tangles represents a mechanism by which RAS medications may slow disease progression.

Connecting the brain cholesterol and renin-angiotensin systems: potential role of statins and RAS-modifying medications in dementia

Millions of people worldwide receive agents targeting the renin-angiotensin system (RAS) to treat hypertension or statins to lower cholesterol. The RAS and cholesterol metabolic pathways in the brain are autonomous from their systemic counterparts and are interrelated through the cholesterol metabolite 27-hydroxycholesterol (27-OHC). These systems contribute to memory and dementia pathogenesis through interference in the amyloid-beta cascade, vascular mechanisms, glucose metabolism, apoptosis, neuroinflammation and oxidative stress. Previous studies examining the relationship between these treatments and cognition and dementia risk have produced inconsistent results. Defining the blood-brain barrier penetration of these medications has been challenging, and the mechanisms of action on cognition are not clearly established. Potential biases are apparent in epidemiological and clinical studies, such as reverse epidemiology, indication bias, problems defining medication exposure, uncertain and changing doses, and inappropriate grouping of outcomes and medications. This review summarizes current knowledge of the brain cholesterol and RAS metabolism and the mechanisms by which these pathways affect neurodegeneration. The putative mechanisms of action of statins and medications inhibiting the RAS will be examined, together with prior clinical and animal studies on their effects on cognition. We review prior epidemiological studies, analysing their strengths and biases, and identify areas for future research. Understanding the pathophysiology of the brain cholesterol system and RAS and their links to neurodegeneration has enormous potential. In future, well-designed epidemiological studies could identify potential treatments for Alzheimer's disease (AD) amongst medications that are already in use for other indications.

Antihypertension drugs in prevention of cognition disorder and dementia: focus on calcium channel blockers and diuretics

Arterial hypertension is associated with elevated risk of cognition decline and vascular dementia development, as the Alzheimer disease development. Therefore, antihypertension therapy might be of preventive value. The review is focused on literary data that witness on, despite controversial, evidence of cerebroprotective action of the range of antihypertension medications. Especially, dihydropyridine calcium antagonists, diuretics and some blockers of renin-angiotensin-aldosterone system. These act not only via blood pressure decrease, but due to additional specific neuroprotective mechanisms. This makes it to consider calcium antagonists and diuretics as a major component of systemic hypertension management, incl. elderly and senile patients, aiming to prevent cognition decline and dementia of various types development.

Nitrendipine, among the calcium channels antagonists, and indapamide among diuretics have acquired the broadest evidence that points on their cerebroprotective properties.

The association of multiple anti-hypertensive medication classes with Alzheimer's disease incidence across sex, race, and ethnicity

BACKGROUND

Antihypertensive treatments have been shown to reduce the risk of Alzheimer's disease (AD). The renin-angiotensin system (RAS) has been implicated in AD, and thus RAS-acting AHTs (angiotensin converting enzyme inhibitors (ACEIs), and angiotensin-II receptor blockers (ARBs)) may offer differential and additional protective benefits against AD compared with other AHTs, in addition to hypertension management.

METHODS

In a retrospective cohort design, we examined the medical and pharmacy claims of a 20% sample of Medicare beneficiaries from 2007 to 2013, and compared rates of AD diagnosis for 1,343,334 users of six different AHT drug treatments, 65 years of age or older (4,215,338 person-years). We compared AD risk between RAS and non-RAS AHT drug users, and between ACEI users and ARB users, by sex and race/ethnicity. Models adjusted for age, socioeconomic status, underlying health, and comorbidities.

FINDINGS

RAS-acting AHTs were slightly more protective against onset of AD than non-RAS-acting AHTs for males, (male OR = 0.931 (CI: 0.895-0.969)), but not so for females (female OR = 0.985 (CI: 0.963-1.007)). Relative to other AHTs, ARBs were superior to ACEIs for both men (male ARB OR = 0.834 (CI: 0.788-0.884); male ACEI OR = 0.978 (CI: 0.939-1.019)) and women (female ARB OR = 0.941 (CI: 0.913-0.969); female ACEI OR = 1.022 (CI: 0.997-1.048)), but only in white men and white and black women. No association was shown for Hispanic men and women.

CONCLUSION

Hypertension management treatments that include RAS-acting ARBs may, in addition to lowering blood pressure, reduce AD risk, particularly for white and black women and white men. Additional studies and clinical trials that include men and women from different racial and ethnic groups are needed to confirm these findings. Understanding the potentially beneficial effects of certain RAS-acting AHTs in high-risk populations is of great importance.

The association between blood pressure variability (BPV) with dementia and cognitive function: a systematic review and meta-analysis protocol

BACKGROUND

A body of empirical work demonstrates that wide fluctuations in a person's blood pressure across consecutive measures, known as blood pressure variability (BPV), hold prognostic value to predict stroke and transient ischemic attack. However, the magnitude of association between BPV and other neurological outcomes remains less clear. This systematic review aims to pool together data regarding BPV with respect to incident dementia, cognitive impairment, and cognitive function.

METHODS

Electronic databases (MEDLINE, EMBASE, and SCOPUS) will be searched for the key words blood pressure variability and outcomes of dementia, cognitive impairment, and cognitive function. Authors and reference lists of included studies will also be contacted to identify additional published and unpublished studies. Eligibility criteria are as follows: population-adult humans (over 18 years but with no upper age limit) without dementia at baseline, with or without elevated blood pressure, or from hypertensive populations (systolic blood pressure ≥ 140 mmHg and/or diastolic blood pressure ≥ 90 mmHg or use of antihypertensive drug for hypertension) and from primary care, community cohort, electronic database registry, or randomized controlled trial (RCT); exposure-any metric of BPV (systolic, diastolic or both) over any duration; comparison-persons without dementia who do not have elevated BPV; and outcome-dementia, cognitive impairment, cognitive function at follow-up from standardized neurological assessment, or cognitive testing. Article screening will be undertaken by two independent reviewers with disagreements resolved through discussion. Data extraction will include original data specified as hazard ratios, odds ratios, correlations, regression coefficients, and original cell data if available. Risk of bias assessment will be undertaken by two independent reviewers. Meta-analytic methods will be used to synthesize the data collected relating to the neurological outcomes with Comprehensive Meta-Analysis Version 2.0 (Biostat Inc., Engelwood, NJ).

DISCUSSION

This systematic review aims to clarify whether BPV is associated with elevated risk for dementia, cognitive impairment, and cognitive function. An evaluation of the etiological links between BPV with incident dementia might inform evidence-based clinical practice and policy concerning blood pressure measurement and hypertension management. The review will identify sources of heterogeneity and may inform decisions on whether it is feasible and desirable to proceed with an individual participant data meta-analysis.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO CRD42017081977.

Exploiting Drug-Apolipoprotein E Gene Interactions in Hypertension to Preserve Cognitive Function: The 3-City Cohort Study

OBJECTIVES

The objective was to test the hypothesis that antihypertensive drugs have a differential effect on cognition in carriers and noncarriers of the apolipoprotein ε4 (APOE4) polymorphism.

DESIGN

Prospective population-based cohort, France.

SETTING AND PARTICIPANTS

A total of 3359 persons using antihypertensive drugs (median age 74 years, 62% women) were serially assessed up to 10 years follow-up.

MEASURES

Exposure to antihypertensive drug use was established in the first 2 years. Cognitive function was assessed at baseline, 2, 4, 7, and 10 years with a validated test battery covering global cognition, verbal fluency, immediate visual recognition memory, processing speed, and executive function. Clinically significant change in cognitive function was determined using reliable change indices represented as z scores and analyzed with linear mixed-models.

RESULTS

From 3359 persons exposed to antihypertensive drugs, 653 were APOE4 carriers (5.1% homozygous, 94.9% heterozygous) and median follow-up was 5.2 years (interquartile range 3.7-8.0). In APOE4 carriers, improved general cognitive function over time was associated with exposure to angiotensin converting enzyme inhibitors [β = .14; 95% confidence interval (CI) .06-.23, P = .001] and angiotensin receptor blockers (β = .11; 95% CI .02-.21, P = .019). Improved verbal fluency was associated with angiotensin converting enzyme inhibitors (β = .11; 95% CI .03-.20, P = .012).

CONCLUSIONS

Renin-angiotensin-system blockade was associated with improved general cognitive function in APOE4 carriers. Findings did not support renin-angiotensin-system drugs' lipophilicity or ability to cross the blood-brain barrier as potential mechanisms. The findings have implications for selecting the optimal antihypertensive drug in older populations at risk of cognitive decline and dementia.

The depressor axis of the renin–angiotensin system and brain disorders: a translational approach

All the components of the classic renin–angiotensin system (RAS) have been identified in the brain. Today, the RAS is considered to be composed mainly of two axes: the pressor axis, represented by angiotensin (Ang) II/angiotensin-converting enzyme/AT1 receptors, and the depressor and protective one, represented by Ang-(1–7)/ angiotensin-converting enzyme 2/Mas receptors. Although the RAS exerts a pivotal role on electrolyte homeostasis and blood pressure regulation, their components are also implicated in higher brain functions, including cognition, memory, anxiety and depression, and several neurological disorders. Overactivity of the pressor axis of the RAS has been implicated in stroke and several brain disorders, such as cognitive impairment, dementia, and Alzheimer or Parkinson’s disease. The present review is focused on the role of the protective axis of the RAS in brain disorders beyond its effects on blood pressure regulation. Furthermore, the use of drugs targeting centrally RAS and its beneficial effects on brain disorders are also discussed.

Clinical Trials of Blood Pressure Lowering and Antihypertensive Medication: Is Cognitive Measurement State-of-the-Art?

Randomized controlled trials of blood pressure (BP) lowering and antihypertensive medication use on cognitive outcomes have often been disappointing, reporting mixed findings and small effect sizes. We evaluate the extent to which cognitive assessment protocols used in these trials approach state-of-the-art. Overall, we find that a primary focus on cognition and the systematic selection of cognitive outcomes across trials take a backseat to other trial goals. Twelve trials investigating change in cognitive functioning were examined and none met criteria for state-of-the-art assessment, including use of at least 4 tests indexing 2 cognitive domains. Four trials investigating incident dementia were also examined. Each trial used state-of-the-art diagnostic criteria to assess dementia, although follow-up periods were relatively short, with only 2 trials lasting for at least 3 years. Weaknesses in each trial may act to obscure or weaken the positive effects of BP lowering on cognitive functioning. Improving trial designs in terms of cognitive outcomes selected and length of follow-up periods employed could lead to more promising findings. We offer logical steps to achieve state-of-the-art assessment protocols, with examples, in hopes of improving future trials.

Exaggerated blood pressure variability is associated with memory impairment in very elderly patients

We investigated the association between working memory (WM) impairment and blood pressure variability (BPV) in very elderly patients. Japanese outpatients ≥80 years who engaged in normal activities of daily living were the study cohort. WM function was evaluated by a simple visual WM test consisting of 3 figures. We considered the number of figures recalled by the patient his/her test score. We defined the patients with a score of 0 or 1 as those with WM impairment and those with scores of 2 or 3 as those without. To investigate the relative risk of WM impairment, we evaluated each patient's 24 hour ambulatory systolic blood pressure (SBP) and its weighted standard deviation (SD_SBP ), office SBP, and the visit-to-visit SD_SBP during the 1 year period from the patient's enrollment. A total of 66 patients (mean 84 ± 3.6 years) showed WM impairment, and 431 patients (mean 83 ± 3.1 years) showed no WM impairment. There were no significant differences in 24 hour ambulatory SBP or office SBP between these two groups. However, the WM impairment patients showed significantly higher weighted SD_SBP and visit-to-visit SD_SBP values compared to the no-impairment group even after adjusting for age. Among these ≥80-year-old patients, those with the highest quartile of both weighted SD_SBP (≥21.4 mm Hg) and visit-to-visit SD_SBP (≥14.5 mm Hg) showed the highest relative risk (odds ratio 3.52, 95% confidence interval 1.42-8.72) for WM impairment. Exaggerated blood pressure variability parameters were significantly associated with working memory impairment in very elderly individuals.

Effects of a new nutraceutical combination on cognitive function in hypertensive patients

Background

Chronic increased arterial blood pressure has been associated with executive dysfunction, slowing of attention and mental processing speed, and later with memory deficits. Due to the absence of a concrete therapeutic approach to this pathophysiological process, in the last decades there has been an increasing interest in the use of nutraceuticals, especially those with antioxidant properties, which own strong neuroprotective potential, that may help to improve cognitive function and to delay the onset of dementia.

Results

We evaluated the effects of the treatment with a new nutraceutical preparation containing different molecules with potent antioxidant properties (AkP05, IzzeK®) and placebo on a cohort of thirty-six hypertensive patients. At baseline, neuropsychological evaluation, arterial stiffness and biochemical parameters of the subjects were comparable. After 6 months of treatment, there was a significant reduction of the augmentation index in the AkP05-treated group. Moreover, the measurement of cognitive function, evaluated with MoCA test and Word Match Testing, showed a significant improvement in patients receiving the active treatment. In addition, the group treated with nutraceutical reached a better Stroop test score, while subjects that received placebo did not showed any improvement. Finally, a positive relationship between SBP variation and the psychometric assessment with the EQ-VAS scale was observed only in the active treatment group.

Conclusions

In this study, we demonstrated that the therapy with a new nutraceutical preparation is able to significantly increase the scores of important neuropsychological tests in hypertensive patients already on satisfactory blood pressure control. Although future studies are needed to better characterize the molecular mechanisms involved, these results candidate the new nutraceutical combination as a possible therapeutic strategy to support the cerebrovascular functions and delay the onset of dementia in hypertensive patients.

The Rationale and Design of the Reducing Pathology in Alzheimer's Disease through Angiotensin TaRgeting (RADAR) Trial

BACKGROUND

Anti-hypertensives that modify the renin angiotensin system may reduce Alzheimer's disease (AD) pathology and reduce the rate of disease progression.

OBJECTIVE

To conduct a phase II, two arm, double-blind, placebo-controlled, randomized trial of losartan to test the efficacy of Reducing pathology in Alzheimer's Disease through Angiotensin TaRgeting (RADAR).

METHODS

Men and women aged at least 55 years with mild-to-moderate AD will be randomly allocated 100 mg encapsulated generic losartan or placebo once daily for 12 months after successful completion of a 2-week open-label phase and 2-week placebo washout to establish drug tolerability. 228 participants will provide at least 182 subjects with final assessments to provide 84% power to detect a 25% difference in atrophy rate (therapeutic benefit) change over 12 months at an alpha level of 0.05. We will use intention-to-treat analysis, estimating between-group differences in outcomes derived from appropriate (linear or logistic) multivariable regression models adjusting for minimization variables.

RESULTS

The primary outcome will be rate of whole brain atrophy as a surrogate measure of disease progression. Secondary outcomes will include changes to 1) white matter hyperintensity volume and cerebral blood flow; 2) performance on a standard series of assessments of memory, cognitive function, activities of daily living, and quality of life. Major assessments (for all outcomes) and relevant safety monitoring of blood pressure and bloods will be at baseline and 12 months. Additional cognitive assessment will also be conducted at 6 months along with safety blood pressure and blood monitoring. Monitoring of blood pressure, bloods, and self-reported side effects will occur during the open-label phase and during the majority of the post-randomization dispensing visits.

CONCLUSION

This study will identify whether losartan is efficacious in the treatment of AD and whether definitive Phase III trials are warranted.

A U-shaped Association Between Blood Pressure and Cognitive Impairment in Chinese Elderly

OBJECTIVES

Higher or lower blood pressure may relate to cognitive impairment, whereas the relationship between blood pressure and cognitive impairment among the elderly is not well-studied. The study objective was to determine whether blood pressure is associated with cognitive impairment in the elderly, and, if so, to accurately describe the association.

DESIGN

Cross-sectional data from the sixth wave of the Chinese Longitudinal Healthy Longevity Survey (CLHLS) conducted in 2011.

SETTING

Community-based setting in longevity areas in China.

PARTICIPANTS

A total of 7144 Chinese elderly aged 65 years and older were included in the sample.

MEASURES

Systolic blood pressures (SBP) and diastolic blood pressures (DBP) were measured, pulse pressure (PP) was calculated as (SBP) - (DBP) and mean arterial pressures (MAP) was calculated as 1/3(SBP) + 2/3(DBP). Cognitive function was assessed via a validated Mini-Mental State Examination (MMSE).

RESULTS

Based on the results of generalized additive models (GAMs), U-shaped associations were identified between cognitive impairment and SBP, DBP, PP, and MAP. The cutpoints at which risk for cognitive impairment (MMSE <24) was minimized were determined by quadratic models as 141 mm Hg, 85 mm Hg, 62 mm Hg, and 103 mm Hg, respectively. In the logistic models, U-shaped associations remained for SBP, DBP, and MAP but not PP. Below the identified cutpoints, each 1-mm Hg decrease in blood pressure corresponded to 0.7%, 1.1%, and 1.1% greater risk in the risk of cognitive impairment, respectively. Above the cutpoints, each 1-mm Hg increase in blood pressure corresponded to 1.2%, 1.8%, and 2.1% greater risk of cognitive impairment for SBP, DBP, and MAP, respectively.

CONCLUSION

A U-shaped association between blood pressure and cognitive function in an elderly Chinese population was found. Recognition of these instances is important in identifying the high-risk population for cognitive impairment and to individualize blood pressure management for cognitive impairment prevention.

Blood pressure from mid- to late life and risk of incident dementia

OBJECTIVE

To determine the association between blood pressure during midlife (40-64 years) to late life (≥65 years) and risk of incident dementia.

METHODS

This study included 1,440 (758 women, mean age 69 ± 6 years) Framingham Offspring participants who were free of dementia and attended 5 consecutive examinations at 4-year intervals starting at midlife (1983-1987, mean age 55 years) until late life (1998-2001, mean 69 years) and subsequently were followed up for incident dementia (mean 8 years). We determined the effect of midlife hypertension (≥140/90 mm Hg), late life hypertension, lower late life blood pressure (<100/70 mm Hg), persistence of hypertension during mid- to late life, and steep decline in blood pressure from mid- to late life over an 18-year exposure period.

RESULTS

During the follow-up period, 107 participants (71 women) developed dementia. Using multivariable Cox proportional hazards models, we found that midlife systolic hypertension (hazard ratio [HR] 1.57, 95% confidence interval [CI] 1.05-2.35) and persistence of systolic hypertension into late life (HR 1.96, 95% CI 1.25-3.09) were associated with an elevated risk of incident dementia. However, in individuals with low to normal blood pressure (≤140/90 mm Hg) at midlife, a steep decline in systolic blood pressure during mid- to late life was also associated with a >2-fold increase in dementia risk (HR 2.40, 95% CI 1.39-4.15).

CONCLUSIONS

Elevated blood pressure during midlife, persistence of elevated blood pressure into late life, and, among nonhypertensives, a steep decline in blood pressure during mid- to late life were associated with an increased dementia risk in a community-based cohort. Our data highlight the potential sustained cognitive benefits of lower blood pressures in midlife but also suggest that declining blood pressure in older adults with prehypertension or normotension, but not in those with hypertension, may be a risk marker for dementia.

Defining Optimal Brain Health in Adults: A Presidential Advisory From the American Heart Association/American Stroke Association

Cognitive function is an important component of aging and predicts quality of life, functional independence, and risk of institutionalization. Advances in our understanding of the role of cardiovascular risks have shown them to be closely associated with cognitive impairment and dementia. Because many cardiovascular risks are modifiable, it may be possible to maintain brain health and to prevent dementia in later life. The purpose of this American Heart Association (AHA)/American Stroke Association presidential advisory is to provide an initial definition of optimal brain health in adults and guidance on how to maintain brain health. We identify metrics to define optimal brain health in adults based on inclusion of factors that could be measured, monitored, and modified. From these practical considerations, we identified 7 metrics to define optimal brain health in adults that originated from AHA's Life's Simple 7: 4 ideal health behaviors (nonsmoking, physical activity at goal levels, healthy diet consistent with current guideline levels, and body mass index <25 kg/m2) and 3 ideal health factors (untreated blood pressure <120/<80 mm Hg, untreated total cholesterol <200 mg/dL, and fasting blood glucose <100 mg/dL). In addition, in relation to maintenance of cognitive health, we recommend following previously published guidance from the AHA/American Stroke Association, Institute of Medicine, and Alzheimer's Association that incorporates control of cardiovascular risks and suggest social engagement and other related strategies. We define optimal brain health but recognize that the truly ideal circumstance may be uncommon because there is a continuum of brain health as demonstrated by AHA's Life's Simple 7. Therefore, there is opportunity to improve brain health through primordial prevention and other interventions. Furthermore, although cardiovascular risks align well with brain health, we acknowledge that other factors differing from those related to cardiovascular health may drive cognitive health. Defining optimal brain health in adults and its maintenance is consistent with the AHA's Strategic Impact Goal to improve cardiovascular health of all Americans by 20% and to reduce deaths resulting from cardiovascular disease and stroke by 20% by the year 2020. This work in defining optimal brain health in adults serves to provide the AHA/American Stroke Association with a foundation for a new strategic direction going forward in cardiovascular health promotion and disease prevention.

Relationship Between Antihypertensive Medications and Cognitive Impairment: Part I. Review of Human Studies and Clinical Trials

Purpose of review

There is an established association between hypertension and increased risk of poor cognitive performance and dementia including Alzheimer’s disease; however, associations between antihypertensive medications (AHMs) and dementia risk are less consistent. An increased interest in AHM has resulted in expanding publications; however, none of the recent reviews are comprehensive. Our extensive review includes 15 observational and randomized controlled trials (RCTs) published over the last 5 years, assessing the relationship between AHM and cognitive impairment.

Recent findings

All classes of AHM showed similar result patterns in human studies with the majority of study results reporting point estimates below one and only a small number of studies (N = 15) reporting statistically significant results in favor of a specific class.

Summary

Only a small number of studies reported statistically significant results in favor of a specific class of AHM. Methodological limitations of the studies prevent definitive conclusions. Further work is now needed to evaluate the class of AHM and cognitive outcomes in future RCTs, with a particular focus on the drugs with the promising results in both animals and human observational studies.

Electronic supplementary material

The online version of this article (doi:10.1007/s11906-016-0674-1) contains supplementary material, which is available to authorized users.

Relationship Between Antihypertensive Medications and Cognitive Impairment: Part II. Review of Physiology and Animal Studies

PURPOSE OF REVIEW

There is an established association between hypertension and increased risk of poor cognitive performance and dementia including Alzheimer's disease; however, associations between antihypertensive medications (AHM) and dementia risk are less clear. An increased interest in AHM has resulted in expanding publications; however, none of the recent reviews provide comprehensive review. Our extensive review includes 24 mechanistic animal and human studies published over the last 5 years assessing relationship between AHM and cognitive function.

RECENT FINDINGS

All classes of AHM showed similar result patterns in animal studies. The mechanism by which AHM exert their effect was extensively studied by evaluating well-established pathways of AD disease process, including amyloid beta (Aβ), vascular, oxidative stress and inflammation pathways, but only few studies evaluated the blood pressure lowering effect on the AD disease process. Methodological limitations of the studies prevent comprehensive conclusions prior to further work evaluating AHM in animals and larger human observational studies, and selecting those with promising results for future RCTs.

Defining the Relationship Between Hypertension, Cognitive Decline, and Dementia: a Review

Hypertension is a highly prevalent condition which has been established as a risk factor for cardiovascular and cerebrovascular disease. Although the understanding of the relationship between cardiocirculatory dysfunction and brain health has improved significantly over the last several decades, it is still unclear whether hypertension constitutes a potentially treatable risk factor for cognitive decline and dementia. While it is clear that hypertension can affect brain structure and function, recent findings suggest that the associations between blood pressure and brain health are complex and, in many cases, dependent on factors such as age, hypertension chronicity, and antihypertensive medication use. Whereas large epidemiological studies have demonstrated a consistent association between high midlife BP and late-life cognitive decline and incident dementia, associations between late-life blood pressure and cognition have been less consistent. Recent evidence suggests that hypertension may promote alterations in brain structure and function through a process of cerebral vessel remodeling, which can lead to disruptions in cerebral autoregulation, reductions in cerebral perfusion, and limit the brain's ability to clear potentially harmful proteins such as β-amyloid. The purpose of the current review is to synthesize recent findings from epidemiological, neuroimaging, physiological, genetic, and translational research to provide an overview of what is currently known about the association between blood pressure and cognitive function across the lifespan. In doing so, the current review also discusses the results of recent randomized controlled trials of antihypertensive therapy to reduce cognitive decline, highlights several methodological limitations, and provides recommendations for future clinical trial design.

Treatment options and considerations for hypertensive patients to prevent dementia

INTRODUCTION

Dementia is a worldwide health concern, which leads to loss of autonomy. To date no curative treatment is available so focus on modifiable risk factors is of particular interest. Hypertension, particularly midlife high blood pressure, has been associated with an increased risk for cognitive decline and dementia including vascular dementia (VAD) and Alzheimer disease (AD). In this context, antihypertensive treatments might have a preventive effect. The objective of this review was to examine the relationship between antihypertensive therapy and cognitive decline or dementia. Areas covered: A literature search was conducted using PUBMED and the COCHRANE LIBRARY for publications from 1990 onwards mentioning cognitive decline, AD, Vad, mixed dementia, vascular cognitive impairment, hypertension and antihypertensive therapy. Thirty-nine relevant publications including 20 longitudinal studies, 10 randomized-controlled trials and 9 meta-analyses were taken into account. Expert opinion: Most observational studies have suggested a potential preventive effect of antihypertensive therapies on cognitive decline and dementia, particularly calcium channel blockers and renin-angiotensin system blockers. Randomized clinical trials and meta-analyses provided more conflicting results potentially due to methodological issues. In conclusion, antihypertensive therapies may reduce cognitive decline and incidence of dementia. Further randomized clinical trials conducted in populations at higher risk of cognitive decline, with longer periods of follow-up and cognition as the primary outcome are still needed.

Memory is preserved in older adults taking AT1 receptor blockers

Background

Prior work suggests that some but not all antihypertensive treatments may benefit cognition and risk for Alzheimer’s disease, independent of stroke. Angiotensin II receptor blockers (ARBs) have been highlighted as one antihypertensive drug class that may confer greatest benefit.

Methods

The participants comprised 1626 nondemented adults, aged 55–91 years, recruited from Alzheimer’s Disease Neuroimaging Initiative sites. Three groups were compared: ARB users (HTN-ARBs), other antihypertensive drug users (HTN-Other), and normotensives. In post hoc analyses, we also examined (1) users of ARBs and angiotensin-converting enzyme inhibitors (ACEIs), (2) users of blood-brain barrier (BBB)-crossing ARBs and users of non-BBB-crossing ARBs, and (3) users of BBB-crossing ARBs and ACEIs (BBB crossers) and users of non-BBB-crossing ARBs and ACEIs (BBB noncrossers). Groups were compared regarding cognition and magnetic resonance imaging measures of brain volume and white matter hyperintensities (WMH), using analysis of covariance and multilevel models.

Results

At baseline, the HTN-Other group performed worse than normotensives on Rey Auditory Verbal Learning Test (RAVLT) Immediate Recall (p = 0.002), Delayed Recall (p < 0.001), Recognition Memory (p = 0.001), and Trails A (p < 0.001) and B (p = 0.01). ARB users performed better than the HTN-Other group on Recognition Memory (p = 0.04) and worse than normotensives on Trails A (p = 0.04). The HTN-Other group performed worse than normotensives on Logical Memory Immediate (p = 0.02) and Delayed Recall over the 3-year follow-up (p = 0.007). Over the follow-up period, those taking BBB-crossing ARBs performed better than the HTN-Other group on AVLT Delayed Recall (p = 0.04), Logical Memory Immediate (p = 0.02), and Delayed Recall (p = 0.05). They also had fewer WMH than the HTN-Other group (p = 0.008) and those taking non-BBB-crossing ARBs (p = 0.05). There were no group differences in brain volume. Users of BBB-crossing medications (ARBs or ACEIs) showed better performance on AVLT Delayed Recall over time than all other groups, including normotensives (all p < 0.01), and had less WMH volume over time than the BBB noncrossers group (p = 0.03), although they had more WMH volume than normotensives (p = 0.01). The BBB noncrossers group performed worse than normotensives on Logical Memory Delayed Recall over time (p = 0.01), but the BBB crossers group was not significantly different (p = 0.13).

Conclusions

Hypertensive participants demonstrated worse baseline memory and executive function, as well as greater memory decline, over the 3-year follow-up than normotensives, unless they were ARB users, who showed preserved memory compared with those taking other antihypertensive drugs. Users of BBB-crossing ARBs showed superior memory performance over time compared with other antihypertensive drug users and had less WMH volume. Users of BBB-crossing medications (ARBs or ACEIs) showed better list-learning memory performance over time than all other groups, including normotensives, and had less WMH volume over time than users of non-BBB-crossing medications. These findings demonstrate that ARBs, especially those of the BBB-crossing variety, are associated with greater memory preservation and less WMH volume than other antihypertensive medications.

Electronic supplementary material

The online version of this article (doi:10.1186/s13195-017-0255-9) contains supplementary material, which is available to authorized users.

Enhanced interstitial fluid drainage in the hippocampus of spontaneously hypertensive rats

Hypertension is associated with cognitive decline and various forms of dementia, including Alzheimer’s disease. In animal models of hypertension, many of Alzheimer’s disease characteristics are recapitulated, including brain atrophy, cognitive decline, amyloid β accumulation and blood brain barrier dysfunction. Removal of amyloid β and other waste products depends in part on clearance via the brain interstitial fluid (ISF). Here we studied the impact of hypertension on ISF drainage, using spontaneously hypertensive rats (SHR) and normotensive Wistar Kyoto rats (WKY). At 8 months, high (500 kD) and low (3 kD) fluorescent molecular weight tracers released passively into the hippocampus showed a drastically enhanced spreading in SHR. Tracer spreading was inhomogeneous, with accumulation at ISF-CSF borders, around arteries, and towards the stratum lacunosum moleculare. These locations stained positively for the astrocyte marker GFAP, and aquaporin 4. Despite enhanced dispersion, clearance of tracers was not affected in SHR. In conclusion, these data indicate enhanced bulk flow of ISF in the hippocampus of hypertensive rats. ISF drains along astrocytes towards the cerebrospinal fluid compartment, which leads to sieving of high molecular weight solutes. Sieving may lead to a local increase in the concentration of waste products and potentially promotes the aggregation of amyloid β.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Effectiveness of a 6-year multidomain vascular care intervention to prevent dementia (preDIVA): a cluster-randomised controlled trial

BACKGROUND

Cardiovascular risk factors are associated with an increased risk of dementia. We assessed whether a multidomain intervention targeting these factors can prevent dementia in a population of community-dwelling older people.

METHODS

In this open-label, cluster-randomised controlled trial, we recruited individuals aged 70-78 years through participating general practices in the Netherlands. General practices within each health-care centre were randomly assigned (1:1), via a computer-generated randomisation sequence, to either a 6-year nurse-led, multidomain cardiovascular intervention or control (usual care). The primary outcomes were cumulative incidence of dementia and disability score (Academic Medical Center Linear Disability Score [ALDS]) at 6 years of follow-up. The main secondary outcomes were incident cardiovascular disease and mortality. Outcome assessors were masked to group assignment. Analyses included all participants with available outcome data. This trial is registered with ISRCTN, number ISRCTN29711771.

FINDINGS

Between June 7, 2006, and March 12, 2009, 116 general practices (3526 participants) within 26 health-care centres were recruited and randomly assigned: 63 (1890 participants) were assigned to the intervention group and 53 (1636 participants) to the control group. Primary outcome data were obtained for 3454 (98%) participants; median follow-up was 6·7 years (21 341 person-years). Dementia developed in 121 (7%) of 1853 participants in the intervention group and in 112 (7%) of 1601 participants in the control group (hazard ratio [HR] 0·92, 95% CI 0·71-1·19; p=0·54). Mean ALDS scores measured during follow-up did not differ between groups (85·7 [SD 6·8] in the intervention group and 85·7 [7·1] in the control group; adjusted mean difference -0·02, 95% CI -0·38 to 0·42; p=0·93). 309 (16%) of 1885 participants died in the intervention group, compared with 269 (16%) of 1634 participants in the control group (HR 0·98, 95% CI 0·80-1·18; p=0·81). Incident cardiovascular disease did not differ between groups (273 [19%] of 1469 participants in the intervention group and 228 [17%] of 1307 participants in the control group; HR 1·06, 95% CI 0·86-1·31; p=0·57).

INTERPRETATION

A nurse-led, multidomain intervention did not result in a reduced incidence of all-cause dementia in an unselected population of older people. This absence of effect might have been caused by modest baseline cardiovascular risks and high standards of usual care. Future studies should assess the efficacy of such interventions in selected populations.

FUNDING

Dutch Ministry of Health, Welfare and Sport; Dutch Innovation Fund of Collaborative Health Insurances; and Netherlands Organisation for Health Research and Development.

Angiotensin II type 1 receptor blockade by telmisartan prevents stress-induced impairment of memory via HPA axis deactivation and up-regulation of brain-derived neurotrophic factor gene expression

Physical and psychological aspects of chronic stress continue to be a persistent clinical problem for which new pharmacological treatment strategies are aggressively sought. By the results of our previous work it has been demonstrated that telmisartan (TLM), an angiotensin type 1 receptor (AT1) blocker (ARB) and partial agonist of peroxisome proliferator-activated receptor gamma (PPARγ), alleviates stress-induced cognitive decline. Understanding of mechanistic background of this phenomenon is hampered by both dual binding sites of TLM and limited data on the consequences of central AT1 blockade and PPARγ activation. Therefore, a critical need exists for progress in the characterization of this target for pro-cognitive drug discovery. An unusual ability of novel ARBs to exert various PPARγ binding activities is commonly being viewed as predominant over angiotensin blockade in terms of neuroprotection. Here we aimed to verify this hypothesis using an animal model of chronic psychological stress (Wistar rats restrained 2.5h daily for 21days) with simultaneous oral administration of TLM (1mg/kg), GW9662 - PPARγ receptor antagonist (0.5mg/kg), or both in combination, followed by a battery of behavioral tests (open field, elevated plus maze, inhibitory avoidance - IA, object recognition - OR), quantitative determination of serum corticosterone (CORT) and evaluation of brain-derived neurotrophic factor (BDNF) gene expression in the medial prefrontal cortex (mPFC) and hippocampus (HIP). Stressed animals displayed decreased recall of the IA behavior (p<0.001), decreased OR (p<0.001), substantial CORT increase (p<0.001) and significantly downregulated expression of BDNF in the mPFC (p<0.001), which were attenuated in rats receiving TLM and TLM+GW9662. These data indicate that procognitive effect of ARBs in stressed subjects do not result from PPAR-γ activation, but AT1 blockade and subsequent hypothalamus-pituitary-adrenal axis deactivation associated with changes in primarily cortical gene expression. This study confirms the dual activities of TLM that controls hypertension and cognition through AT1 blockade.

p38 MAPK Inhibition Improves Synaptic Plasticity and Memory in Angiotensin II-dependent Hypertensive Mice

The pathogenesis of hypertension-related cognitive impairment has not been sufficiently clarified, new molecular targets are needed. p38 MAPK pathway plays an important role in hypertensive target organ damage. Activated p38 MAPK was seen in AD brain tissue. In this study, we found that long-term potentiation (LTP) of hippocampal CA1 was decreased, the density of the dendritic spines on the CA1 pyramidal cells was reduced, the p-p38 protein expression in hippocampus was elevated, and cognitive function was impaired in angiotensin II-dependent hypertensive C57BL/6 mice. In vivo, using a p38 heterozygous knockdown mice (p38(KI/+)) model, we showed that knockdown of p38 MAPK in hippocampus leads to the improvement of cognitive function and hippocampal synaptic plasticity in angiotensin II-dependent p38(KI/+) hypertensive mice. In vitro, LTP was improved in hippocampal slices from C57BL/6 hypertensive mice by treatment with p38MAPK inhibitor SKF86002. Our data demonstrated that p38 MAPK may be a potential therapeutic target for hypertension-related cognitive dysfunction.

Effects of vascular risk factors, statins, and antihypertensive drugs on PiB deposition in cognitively normal subjects

INTRODUCTION

Hypertension, hypercholesterolemia, and obesity increase the risk of dementia. Although their detection is commonly followed by an introduction of treatment, little is known about how medications frequently used to treat vascular risk affect amyloid deposition.

METHODS

A cross-sectional study of 156 subjects who underwent positron emission tomography with PiB. Using linear regression, we tested whether blood pressure, cholesterol, overweight/obese status, angiotensin receptor blockers (ARBs), beta-blockers, diuretics, angiotensin converting enzyme inhibitors, and statins predicted amyloid deposition.

RESULTS

The use of ARBs (β = -.15, P = .044) and diuretics (β = -.20, P = .006) predicted less amyloid accumulation; older age (β = .29, P < .001) and statins (β = .23, P = .004) were related to greater amyloid deposition. Overweight and/or obese women had more cortical amyloid than their peers.

DISCUSSION

Prospective studies should confirm effects of drugs and increased body weight on amyloid accumulation and establish whether they translate into measurable clinical outcomes. Women may be more susceptible to harmful effects of obesity.

Effects of Blood Pressure Lowering With Different Antihypertensive Agents on Cognitive Function and Plasma Brain-derived Neurotrophic Factor Levels: A Comparative Study

PURPOSE

Hypertension is a risk factor for cognitive impairment (CI). However, the specific effect of antihypertensive therapy on cognitive function is still controversial. We aimed to investigate the effect of antihypertensive agents targeting the renin-angiotensin system (RAS) on CI and brain-derived neurotropic factor (BDNF).

METHODS

We included 62 patients who had been using the same antihypertensive agent for at least 3 months. Patients who had relevant conditions that could contribute to CI were excluded. After subjects were divided into 3 groups according to their current antihypertensive medication, the cognitive status of each patient was assessed by the mini-mental state examination (MMSE). BDNF and plasma renin activity were evaluated.

RESULTS

There was a negative association between systolic blood pressure and MMSE independent of medication (rho = -0.251, P = 0.049). There was no significant correlation between MMSE and BDNF. The MMSE score was slightly higher in the non-RAS group, but the difference did not reach statistical significance (P = 0.09). There was also no significant difference in BDNF levels between study groups (P = 0.32). Mean plasma renin activity levels were significantly lower in the non-RAS group compared with the angiotensin converting enzyme inhibitor and angiotensin receptor blocker groups (P = 0.007).

CONCLUSIONS

We suggest that the essential intervention for CI in hypertensive patients is appropriate for blood pressure control.

Evidence-Based Heart Failure Medications and Cognition

BACKGROUND

The etiology of cognitive impairment in heart failure (HF) is controversial and likely multifactorial. Physicians may hesitate to prescribe evidence-based HF medication because of concerns related to potential negative changes in cognition among a population that is already frequently impaired. We conducted a study to determine if prescription of evidence-based HF medications (specifically, β-blockers, angiotensin-converting enzyme inhibitors, angiotensin-receptor blocking agents, diuretics, and aldosterone inhibitors) was associated with cognition in a large HF sample.

METHODS

A total of 612 patients completed baseline data collection for the Rural Education to Improve Outcomes in Heart Failure clinical trial, including information about medications. Global cognition was evaluated using the Mini-Cog.

RESULTS

The sample mean (SD) age was 66 (13) years, 58% were men, and 89% were white. Global cognitive impairment was identified in 206 (34%) of the 612 patients. Prescription of evidence-based HF medications was not related to global cognitive impairment in this sample. This relationship was maintained even after adjusting for potential confounders (eg, age, education, and comorbid burden).

CONCLUSION

Prescription of evidence-based HF medications is not related to low scores on a measure of global cognitive function in rural patients with HF.

Antihypertensive Therapies and Cognitive Function: a Review

Increasing life expectancy has made old age-related health problems like dementia and cognitive decline more prevalent, and these are rapidly becoming important causes of disability and poor quality of life, causing significant add-ons to health-care costs worldwide. Hypertension is the most important modifiable vascular risk factor for the development and progression of both cognitive decline and dementia. In many observational and randomized studies, antihypertensive therapies have been shown to be beneficial in slowing cognitive decline. However, due to observed discrepancies by these studies, there is a lack of consensus on the best antihypertensive strategy for the prevention or slowing of cognitive decline. It is also not clear whether the beneficial effect of antihypertensive therapy is due to the use of a specific class of agents or combination therapy. Thus, we present a comprehensive review of overall antihypertensive therapies and cognition and of the individual antihypertensive therapy classes with their specific protective mechanisms and available clinical evidence behind their effect on cognitive function.

Risk of dementia in seniors with newly diagnosed diabetes: a population-based study

OBJECTIVE

To study whether diabetes onset in late life is a risk factor for dementia.

RESEARCH DESIGN AND METHODS

We conducted a population-based matched cohort study using provincial health data from Ontario, Canada. Seniors with (n = 225,045) and without newly diagnosed diabetes (n = 668,070) between April 1995 and March 2007 were followed until March 2012 for a new diagnosis of dementia. Cox proportional hazards modeling was used to compare the risk of dementia between groups after adjusting for baseline cardiovascular disease, chronic kidney disease (CKD), hypertension, and other risk factors.

RESULTS

Over this period, we observed 169,114 new cases of dementia. Individuals with diabetes had a modestly higher incidence of dementia (2.68 vs. 2.62 per 100 person-years) than those without diabetes. In the fully adjusted Cox model, the risk of dementia was 16% higher among our subgroup with diabetes (hazard ratio [HR] 1.16 [95% CI 1.15-1.18]). Adjusted HRs for dementia were 1.20 (95% CI 1.17-1.22) and 1.14 (95% CI 1.12-1.16) among men and women, respectively. Among seniors with diabetes, the risk of dementia was greatest in those with prior cerebrovascular disease (HR 2.03; 95% CI 1.88-2.19), peripheral vascular disease (HR 1.47; 95% CI 1.19-1.82), and CKD (HR 1.44; 95% CI 1.38-1.51), and those with one or more hospital visits for hypoglycemia (HR 1.73; 95% CI 1.62-1.84).

CONCLUSIONS

In this population-based study, newly diagnosed diabetes was associated with a 16% increase in the risk of dementia among seniors. Preexisting vascular disease and severe hypoglycemia were the greatest risk factors for dementia in seniors with diabetes.

Angiotensin receptor blockers and risk of dementia: cohort study in UK Clinical Practice Research Datalink

Aims

This was a cohort study to evaluate whether individuals exposed to angiotensin receptor blockers have a reduced risk of dementia compared with those exposed to angiotensin-converting enzyme inhibitors.

Methods

The study included new users of angiotensin receptor blockers or angiotensin-converting enzyme inhibitors (from 1995 to 2010) from UK primary care practices contributing to the Clinical Research Practice Datalink. The association between exposure to angiotensin receptor blockers and the risk of incident dementia was analysed using a Cox model, adjusting for age, sex, body mass index, diabetes, hypertension, heart failure, statin use, socioeconomic status, alcohol, smoking, number of consultations and calendar year.

Results

A total of 426 089 persons were included in the primary analysis, with 45 541 persons exposed to angiotensin receptor blockers and the remainder to angiotensin-converting enzyme inhibitors. The total number of new diagnoses of dementia was 6517. There was weak evidence of a decreased risk of dementia with exposure to angiotensin receptor blockers, with follow-up beginning at 1 year after the start of treatment (adjusted hazard ratio 0.92, 95% confidence interval 0.85–1.00). An analysis restricted to the first 12 months after the index date showed a larger effect on dementia risk (adjusted hazard ratio 0.60, 95% confidence interval 0.50–0.72).

Conclusions

A small reduction in dementia risk was seen with angiotensin receptor blockers in comparison to angiotensin-converting enzyme inhibitors. However, the strongest association was seen in early follow-up, suggesting that the inverse association is unlikely to be causal, but instead reflects other important but unmeasured differences between angiotensin receptor blocker and angiotensin-converting enzyme inhibitor users.

Checking the STEP-Associated Trafficking and Internalization of Glutamate Receptors for Reduced Cognitive Deficits: A Machine Learning Approach-Based Cheminformatics Study and Its Application for Drug Repurposing

BACKGROUND

Alzheimer's disease, a lethal neurodegenerative disorder that leads to progressive memory loss, is the most common form of dementia. Owing to the complexity of the disease, its root cause still remains unclear. The existing anti-Alzheimer's drugs are unable to cure the disease while the current therapeutic options have provided only limited help in restoring moderate memory and remain ineffective at restricting the disease's progression. The striatal-enriched protein tyrosine phosphatase (STEP) has been shown to be involved in the internalization of the receptor, N-methyl D-aspartate (NMDR) and thus is associated with the disease. The present study was performed using machine learning algorithms, docking protocol and molecular dynamics (MD) simulations to develop STEP inhibitors, which could be novel anti-Alzheimer's molecules.

METHODS

The present study deals with the generation of computational predictive models based on chemical descriptors of compounds using machine learning approaches followed by substructure fragment analysis. To perform this analysis, the 2D molecular descriptors were generated and machine learning algorithms (Naïve Bayes, Random Forest and Sequential Minimization Optimization) were utilized. The binding mechanisms and the molecular interactions between the predicted active compounds and the target protein were modelled using docking methods. Further, the stability of the protein-ligand complex was evaluated using MD simulation studies. The substructure fragment analysis was performed using Substructure fingerprint (SubFp), which was further explored using a predefined dictionary.

RESULTS

The present study demonstrates that the computational methodology used can be employed to examine the biological activities of small molecules and prioritize them for experimental screening. Large unscreened chemical libraries can be screened to identify potential novel hits and accelerate the drug discovery process. Additionally, the chemical libraries can be searched for significant substructure patterns as reported in the present study, thus possibly contributing to the activity of these molecules.

Cognitive function in patients with diabetes mellitus: guidance for daily care

Diabetes mellitus is associated with an increase in the risk of dementia and the proportion of patients who convert from mild cognitive impairment (MCI) to dementia. In addition to MCI and dementia, the stages of diabetes-associated cognitive dysfunction include subtle cognitive changes that are unlikely to affect activities of daily life or diabetes self-management. These diabetes-associated cognitive decrements have structural brain correlates detectable with brain MRI, but usually show little progression over time. Although cognitive decrements do not generally represent a pre-dementia stage in patients below the age of 60-65 years, in older individuals these subtle cognitive changes might represent the earliest stages of a dementia process. Acknowledgment of diabetes-associated cognitive decrements can help to improve understanding of patients' symptoms and guide management. Future challenges are to establish the importance of screening for cognitive impairment in people with diabetes, to identify those at increased risk of accelerated cognitive decline at an early stage, and to develop effective treatments.

Antihypertensive drugs, prevention of cognitive decline and dementia: a systematic review of observational studies, randomized controlled trials and meta-analyses, with discussion of potential mechanisms

BACKGROUND

Chronic hypertension, particularly midlife high blood pressure, has been associated with an increased risk for cognitive decline and dementia. In this context, antihypertensive drugs might have a preventive effect, but the association remains poorly understood.

OBJECTIVES

The aim of this systematic review was to examine all published findings that investigated this relationship and discuss the mechanisms underlying the potential benefits of antihypertensive medication use.

METHODS

A literature search was conducted using MEDLINE, Embase, and the Cochrane Library for publications from 1990 onwards mentioning hypertension, antihypertensive drugs, cognitive decline, and dementia.

RESULTS

A total of 38 relevant publications, corresponding to 18 longitudinal studies, 11 randomized controlled trials, and nine meta-analyses were identified from the 10,251 articles retrieved in the literature search. In total, 1,346,176 subjects were included in these studies; the average age was 74 years. In the seven longitudinal studies assessing the effect of antihypertensive medication on cognitive impairment or cognitive decline, antihypertensive drugs appeared to be beneficial. Of the 11 longitudinal studies that assessed the effect of antihypertensive medication on incidence of dementia, only three did not find a significant protective effect. Antihypertensive medication could decrease the risk of not only vascular dementia but also Alzheimer's disease. Four randomized controlled trials showed a potentially preventive effect of antihypertensive drugs on the incidence of dementia or cognitive decline: SYST-EUR (Systolic Hypertension in Europe Study) I and II, with a 55% reduction in dementia risk (3.3 vs. 7.4 cases per 1,000 patient years; p<0.001); HOPE (Heart Outcomes Prevention Evaluation), with a 41% reduction in cognitive decline associated with stroke (95% confidence interval [CI] 6-63); and PROGRESS (Perindopril Protection against Recurrent Stroke Study), with a 19% reduction in cognitive decline (95% CI 4-32; p=0.01). Meta-analyses have sometimes produced conflicting results, but this may be due to methodological considerations. The lack of homogeneity across study designs, patient populations, exposition, outcomes, and duration of follow-up are the most important methodological limitations that might explain the discrepancies between some of these studies.

CONCLUSION

Antihypertensive drugs, particularly calcium channel blockers and renin-angiotensin system blockers, may be beneficial in preventing cognitive decline and dementia. However, further randomized controlled trials with longer periods of follow-up and cognition as the primary outcome are needed to confirm these findings.