Protective effect of anti-hypertensive treatment on cognitive function in essential hypertension: analysis of published clinical data

Enhancing Fear Extinction: Pharmacological Approaches

Extinction is the process by which the memory of a learned conditioned association decreases over time and with introduction of new associations. It is a vital part of fear learning, and it is critical to recovery in multiple fear-related disorders, including Specific and Social Phobias, Panic Disorder, Obsessive Compulsive Disorder (OCD), and Posttraumatic Stress Disorder (PTSD). The process of extinction is also the underlying mechanism for recovery in gold-standard therapies for PTSD, including prolonged exposure, cognitive processing therapy, eye movement desensitization and procession, as well as other empirically-based paradigms. Pharmacological modulators of extinction are thus promising targets for treatment of fear-related disorders. We focus here on emerging psychopharmacological treatments to facilitate extinction: D-cycloserine, scopolamine, losartan, ketamine, and 3,4-methylenedioxymethamphetamine. We also provide an overview of recent advances in molecular pathways that show promise as targets for extincion and inhibitory learning, including pathways related to cannabinoid, brain-derived neurotrophic factor, hypothalamic-pituitary-adrenal signaling, and promising work in neurosteroid compounds.

The Correlation between Two Angiotensin-Converting Enzyme Inhibitor's Concentrations and Cognition

Both lisinopril and enalapril are angiotensin-converting enzyme (ACE) drugs and widely used in the treatment of hypertension. Enalapril does not cross the blood-brain barrier, but lisinopril is centrally active. Our goal was to find out if there was a link between the actual concentration of ACE inhibitors and cognition and if there was a detectable difference between the two types of ACE inhibitors. Asymptomatic, non-treated patients were diagnosed by screening and the hypertension was confirmed by ambulatory blood pressure monitoring (ABPM). A battery of cognitive tests was used to assess the impact of randomly assigning participants to receive either lisinopril or enalapril. All neurocognitive functions were measured, especially the most affected by conditions of compromised perfusion pressures, such as hypertension, which are attention and executive functions. The lisinopril concentration showed a significant inverse correlation with mosaic test (coeff. = -0.5779) and seemed to have a significant negative effect on perceptual motor skills (coeff. = -0.5779), complex attention (coeff. = -0.5104) and learning (coeff. = -0.5202). Compared with enalapril, lisinopril is less successful in improving the components of cognitive functions.

Exercise Normalized the Hippocampal Renin-Angiotensin System and Restored Spatial Memory Function, Neurogenesis, and Blood-Brain Barrier Permeability in the 2K1C-Hypertensive Mouse

Hypertension is associated with blood-brain barrier alteration and brain function decline. Previously, we established the 2-kidney,1-clip (2K1C) hypertensive mice model by renin-angiotensin system (RAS) stimulating. We found that 2K1C-induced hypertension would impair hippocampus-related memory function and decrease adult hippocampal neurogenesis. Even though large studies have investigated the mechanism of hypertension affecting brain function, there remains a lack of efficient ways to halt this vicious effect. The previous study indicated that running exercise ameliorates neurogenesis and spatial memory function in aging mice. Moreover, studies showed that exercise could normalize RAS activity, which might be associated with neurogenesis impairment. Thus, we hypothesize that running exercise could ameliorate neurogenesis and spatial memory function impairment in the 2K1C-hypertension mice. In this study, we performed 2K1C surgery on eight-weeks-old C57BL/6 mice and put them on treadmill exercise one month after the surgery. The results indicate that running exercise improves the spatial memory and neurogenesis impairment of the 2K1C-mice. Moreover, running exercise normalized the activated RAS and blood-brain barrier leakage of the hippocampus, although the blood pressure was not decreased. In conclusion, running exercise could halt hypertension-induced brain impairment through RAS normalization.

Visit-to-Visit Blood Pressure Variability and Longitudinal Tau Accumulation in Older Adults

BACKGROUND

Elevated blood pressure variability (BPV) is predictive of dementia, independent of average blood pressure levels, but neuropathological mechanisms remain unclear. We examined whether BPV in older adults is related to tau accumulation in brain regions vulnerable to Alzheimer disease and whether relationships are modified by apoϵ4 carrier status.

METHODS

Two hundred eighty-six Alzheimer's Disease Neuroimaging Initiative participants without history of dementia underwent 3 to 4 blood pressure measurements over 12 months and ≥1 tau positron emission tomography thereafter. BPV was calculated as variability independent of mean. Each scan determined tau burden (standardized uptake value ratio) for a temporal meta-region of interest, including burden from entorhinal cortex, amygdala, parahippocampus, fusiform, inferior temporal, and middle temporal. Bayesian linear growth modeling examined the role of BPV, apolipoprotein ϵ4 carrier status, and time on regional tau accumulation after controlling for several variables, including baseline hypertension.

RESULTS

Elevated BPV was related to tau accumulation at follow-up in a temporal meta-region, independent of average blood pressure levels (ß, 0.89 [95% credible interval, 0.86-0.92]) and especially in entorhinal cortex (ß, 2.57 [95% credible interval, 2.15-2.99]). Apoϵ4 carriers with elevated BPV had the fastest tau accumulation at follow-up (ß, 1.73 [95% credible interval, 0.47-3.03]).

CONCLUSIONS

BPV is related to tau accumulation in brain regions vulnerable to Alzheimer disease, independent of average blood pressure. APOEϵ4 modified this relationship. Bidirectionality of findings is possible. BPV may represent a marker of vascular dysfunction related to early-stage tau pathology contributing to Alzheimer disease.

Antemortem Visit-To-Visit Blood Pressure Variability Predicts Cerebrovascular Lesion Burden in Autopsy-Confirmed Alzheimer's Disease

BACKGROUND

Blood pressure variability is linked to Alzheimer's disease (AD) risk and MRI-based markers of cerebrovascular disease. Less is known about the role of blood pressure variability in postmortem evaluation of cerebrovascular disease and AD.

OBJECTIVE

To determine whether antemortem blood pressure variability predicts cerebrovascular and AD pathology and follow-up cognitive change in autopsy-confirmed AD.

METHODS

National Alzheimer's Coordinating Center participants (n = 513) underwent 3-4 approximately annual blood pressure measurements and were confirmed to have AD at postmortem evaluation. A subset (n = 493) underwent neuropsychological evaluation at follow-up. Regression models examined relationships between blood pressure variability and cerebrovascular and AD pathological features and follow-up cognitive change.

RESULTS

Elevated blood pressure variability predicted increased postmortem cerebrovascular lesion burden (ß = 0.26 [0.10, 0.42]; p = 0.001; R2 = 0.12). Increased blood pressure variability predicted specific cerebrovascular lesion severity, including atherosclerosis in the Circle of Willis (OR = 1.22 [1.03, 1.44]; p = 0.02) and cerebral arteriolosclerosis (OR = 1.32 [1.04, 1.69]; p = 0.03). No significant relationships were observed between blood pressure variability and AD pathological findings, including Braak & Braak stage, neuritic plaques or diffuse plaques, or cerebral amyloid angiopathy, or follow-up cognitive decline.

CONCLUSION

Findings suggest that elevated blood pressure variability is related to postmortem cerebrovascular lesion burden in autopsy-confirmed AD, independent of average blood pressure and AD neuropathology. Blood pressure fluctuation may selectively promote atherosclerotic and arteriolosclerotic brain lesions with potential implications for cognitive impairment and dementia.

Enhanced purification protocol for the angiotensin-converting enzyme from bovine systems and investigation of the in vitro effect of some active substances

Angiotensin-converting enzyme (ACE, EC 3.4.15.1) synthesized by endothelial cells and responsible for the regulation of blood pressure was purified from the bovine lung with affinity chromatography method. The purification rate of the ACE of the bovine lung was calculated as 1748- fold. Optimum pH and optimum temperature for the purified ACE were found to be 7.6 and 35-40 °C, respectively. The purity and molecular weight of the ACE were designated with SDS-PAGE. The ACE was found to have three subunits with molecular weights of 57 kDa, 66 kDa, and 190 kDa. Then, the total molecular weight of the ACE was designated as 303 kDa with gel filtration chromatography. The effects of ACE inhibitors captopril, fosinopril, lisinopril, and beta-blockers propranolol, atenolol, and diuretic triamterene on ACE activity were studied. ACE inhibitors lisinopril, captopril, fosinopril, and diuretic triamterene demonstrated an inhibition effect on ACE activity. Beta-blockers indicated no effect on ACE. IC₅₀ values of captopril, fosinopril, lisinopril, and triamterene from the graphical equation were calculated as 0.835 nM, 1.159 μM, 4.085 nM, and 227 μM, respectively. The inhibition type and K_i values of these compounds were determined from Lineweaver-Burk plots. Captopril, fosinopril, lisinopril, and triamterene demonstrated a non-competitive inhibition effect on ACE activity. K_i constants were found as 1.057 nM, 1.675 μM, 6.449 nM, and 419.5 μM, respectively. Captopril indicated the highest inhibitor effect with an IC₅₀ value of 0.835 nM.

Long-term effect of masked hypertension management on cognitive functions in geriatric age: geriatric MASked hypertension and cognition follow-up study (G-MASH-cog MONITOR)

OBJECTIVES

Masked hypertension, defined as nonelevated clinic blood pressure with elevated out of clinic blood pressure, has been associated with increased cardiovascular events, mortality and cognitive impairment. No evidence exists regarding the effect of treating masked hypertension. In this study, we followed-up the patients in the G-MASH-cog study for 1 year and aimed to examine the effect of the management of masked hypertension on cognitive functions.

METHODS

The G-MASH-cog study participants were followed-up for 1 year. In masked hypertensive individuals, lifestyle modification and antihypertensive treatment (perindopril or amlodipine) were initiated for blood pressure control. Measurements of cognitive tests and ambulatory blood pressure monitoring at baseline and at 1-year follow-up were compared.

RESULTS

A total of 61 patients (30 in masked hypertension group; 31 in normotensive group) were included. Mean age was 72.3 ± 5.1 and 59% of the participants were female. Compared with baseline ambulatory blood pressure measurement results, patients with masked hypertension had significantly lower ambulatory blood pressure measurement results after 1-year follow-up. The quick mild cognitive impairment test (Q-MCI-TR) score increased with antihypertensive treatment (Q-MCI score at baseline = 41(19-66.5), at 1 year = 45.5 (22-70), P = 0.005) in masked hypertensive patients. In the final model of the mixed-effects analysis, when adjusted for covariates, interaction effect of the masked hypertension treatment with time was only significant in influencing the changes in Q-MCI scores over time in patients aged between 65 and 74 years (P = 0.002).

CONCLUSIONS

Treatment of masked hypertension in older adults was associated with improvement in cognitive functions.

Longitudinal trajectories of metabolic syndrome on different neurocognitive domains: a cohort study from the Taiwan biobank

Metabolic syndrome (MetS) brings considerable effects on cognitive function, but trajectories within remain unclear. We investigated the interactions between distinct MetS components and cognitive domains. A total of 5693 participants from the Taiwan biobank during 2008–2018 were enrolled. Participants were classified as either normal or as having MetS at two time points; i.e., study entry and follow-up. At both the time points, cognitive evaluations using the Mini-Mental State Examination (MMSE) were conducted. The hazard ratios (HRs) of mild cognitive impairment (MCI) and dementia were higher in participants meeting more diagnostic components of MetS. Of the five criteria of MetS, three were significantly associated with MCI and dementia: high blood pressure (MCI: HR = 1.203, p < 0.001; dementia: HR = 1.345, p < 0.001), abdominal obesity (MCI: HR = 1.137, p = 0.006; dementia: HR = 1.442, p < 0.001), and low high-density lipoprotein (HDL) level (MCI: HR = 1.149, p = 0.007; dementia: HR = 1.364, p < 0.001). Of the cognitive domains measured, three were significantly associated with MetS; namely, orientation, language, and visuospatial abilities. Participants who were initially diagnosed with MetS but were normal at follow-up had an HR of 1.374 for dementia (p = 0.019), which was beyond our expectations. The undiminished risk of cognitive decline in subjects returning to normal status illustrated that neural injury caused by MetS takes a long time to get repaired. Consequently, earlier detection and management of adjustable risk factors of MetS should be encouraged to minimize the damage.

Brain Renin-Angiotensin System at the Intersect of Physical and Cognitive Frailty

The renin–angiotensin system (RAS) was initially considered to be part of the endocrine system regulating water and electrolyte balance, systemic vascular resistance, blood pressure, and cardiovascular homeostasis. It was later discovered that intracrine and local forms of RAS exist in the brain apart from the endocrine RAS. This brain-specific RAS plays essential roles in brain homeostasis by acting mainly through four angiotensin receptor subtypes; AT₁R, AT₂R, MasR, and AT₄R. These receptors have opposing effects; AT₁R promotes vasoconstriction, proliferation, inflammation, and oxidative stress while AT₂R and MasR counteract the effects of AT₁R. AT₄R is critical for dopamine and acetylcholine release and mediates learning and memory consolidation. Consequently, aging-associated dysregulation of the angiotensin receptor subtypes may lead to adverse clinical outcomes such as Alzheimer’s disease and frailty via excessive oxidative stress, neuroinflammation, endothelial dysfunction, microglial polarization, and alterations in neurotransmitter secretion. In this article, we review the brain RAS from this standpoint. After discussing the functions of individual brain RAS components and their intracellular and intracranial locations, we focus on the relationships among brain RAS, aging, frailty, and specific neurodegenerative diseases, such as Alzheimer’s disease, Parkinson’s disease, and vascular cognitive impairment, through oxidative stress, neuroinflammation, and vascular dysfunction. Finally, we discuss the effects of RAS-modulating drugs on the brain RAS and their use in novel treatment approaches.

Dementia and the heart failure patient

Heart and brain disorders more frequently co-exist than by chance alone, due to having common risk factors and a degree of interaction. In the setting of heart failure (HF) in the elderly strokes, dementia, and depression are all common and can produce a particularly difficult series of clinical problems to manage. Loss of ability to self-care can lead to very poor quality of life and a dramatic increase in health care expenditure. The Heart Failure Association of the ESC as part of its workshop on physiological monitoring of the complex multi-morbid HF patient reviewed screening, monitoring, prevention, and management of cognitive decline within the setting of HF.

The Oxford study of Calcium channel Antagonism, Cognition, Mood instability and Sleep (OxCaMS): study protocol for a randomised controlled, experimental medicine study

Background

The discovery that voltage-gated calcium channel genes such as CACNA1C are part of the aetiology of psychiatric disorders has rekindled interest in the therapeutic potential of L-type calcium channel (LTCC) antagonists. These drugs, licensed to treat hypertension and angina, have previously been used in bipolar disorder, but without clear results. Neither is much known about the broader effects of these drugs on the brain and behaviour.

Methods

The Oxford study of Calcium channel Antagonism, Cognition, Mood instability and Sleep (OxCaMS) is a high-intensity randomised, double-blind, placebo-controlled experimental medicine study on the effect of the LTCC antagonist nicardipine in healthy young adults with mood instability. An array of cognitive, psychiatric, circadian, physiological, biochemical and neuroimaging (functional magnetic resonance imaging and magnetoencephalography) parameters are measured during a 4-week period, with randomisation to drug or placebo on day 14. We are interested in whether nicardipine affects the stability of these measures, as well as its overall effects. Participants are genotyped for the CACNA1C risk polymorphism rs1006737.

Discussion

The results will clarify the potential of LTCC antagonists for repurposing or modification for use in psychiatric disorders in which cognition, mood and sleep are affected.

Trial registration

ISRCTN, ISRCTN33631053. Retrospectively registered on 8 June 2018 (applied 17 May 2018).

Electronic supplementary material

The online version of this article (10.1186/s13063-019-3175-0) contains supplementary material, which is available to authorized users.

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.

Changes in Cognitive Function Following Bariatric Surgery: a Systematic Review

Increased body mass is directly associated with reduced cognitive function. The aim of this study was to systematically review the effect of bariatric weight loss surgery on cognitive function. A comprehensive and unrestricted literature search was conducted using the following databases: MEDLINE, EMBASE, PubMed, Scopus, Web of Sciences, and the Cochrane Library. A total of 414 publications were identified, of which 18 were included in the final review. Cognitive function as measured by a number of different assessment tools was shown to improve following surgically induced weight loss in most studies. Significant and rapid weight loss resulting from bariatric surgery is associated with prompt and sustained improvements in cognitive function including memory, executive function, and cognitive control.

Comparative Solid-State Stability of Perindopril Active Substance vs. Pharmaceutical Formulation

This paper presents the results obtained after studying the thermal stability and decomposition kinetics of perindopril erbumine as a pure active pharmaceutical ingredient as well as a solid pharmaceutical formulation containing the same active pharmaceutical ingredient (API). Since no data were found in the literature regarding the spectroscopic description, thermal behavior, or decomposition kinetics of perindopril, our goal was the evaluation of the compatibility of this antihypertensive agent with the excipients in the tablet under ambient conditions and to study the effect of thermal treatment on the stability of perindopril erbumine. ATR-FTIR (Attenuated Total Reflectance Fourier Transform Infrared) spectroscopy, thermal analysis (thermogravimetric mass curve (TG-thermogravimetry), derivative thermogravimetric mass curve (DTG), and heat flow (HF)) and model-free kinetics were chosen as investigational tools. Since thermal behavior is a simplistic approach in evaluating the thermal stability of pharmaceuticals, in-depth kinetic studies were carried out by classical kinetic methods (Kissinger and ASTM E698) and later with the isoconversional methods of Friedman, Kissinger-Akahira-Sunose and Flynn-Wall-Ozawa. It was shown that the main thermal degradation step of perindopril erbumine is characterized by activation energy between 59 and 69 kJ/mol (depending on the method used), while for the tablet, the values were around 170 kJ/mol. The used excipients (anhydrous colloidal silica, microcrystalline cellulose, lactose, and magnesium stearate) should be used in newly-developed generic solid pharmaceutical formulations, since they contribute to an increased thermal stability of perindopril erbumine.

Towards Optimal Heart Failure Care: Couples-Oriented Strategies to Improve Patient Adherence and Health Outcomes

Psychosocial factors play an important role in the development and progression of cardiovascular diseases (CVD), such as chronic heart failure (CHF). In particular, psycho-cognitive disturbance is common in CHF, which presents additional challenges to secondary prevention and management strategies. This review provides a summary of the contemporary psycho-cardiology literature, including coverage of common mood and cognitive symptoms, and explores some of the pathophysiologic evidence linking psycho-cognition to CHF, with particular emphasis on sympathetic nervous system activation and neuroendocrine functioning. Social support is identified as a strategy by which to reduce depressive symptoms, manage cognitive impairment and to, potentially, improve health outcomes through improved patient self care and adherence. Recent research outcomes suggest that the integration of family caregivers into CHF psycho-educational disease management programs, as providers and recipients of support, may achieve best outcomes. In this regard, couples-oriented strategies that promote communication, emotional attachment and support may enhance health-promoting behaviours in patients and their partners.

Brain angiotensin-(1-7)/Mas axis: A new target to reduce the cardiovascular risk to emotional stress

Emotional stress is now considered a risk factor for several diseases including cardiac arrhythmias and hypertension. It is well known that the activation of neuroendocrine and autonomic mechanisms features the response to emotional stress. However, its link to cardiovascular diseases and the regulatory mechanisms involved remain to be further comprehended. The renin-angiotensin system (RAS) plays an important role in homeostasis on all body systems. Specifically in the brain, the RAS regulates a number of physiological aspects. Recent data indicate that the activation of angiotensin-converting enzyme/angiotensin II/AT1 receptor axis facilitates the emotional stress responses. On the other hand, growing evidence indicates that its counterregulatory axis, the angiotensin-converting enzyme 2 (ACE2)/(Ang)iotensin-(1-7)/Mas axis, reduces anxiety and attenuates the physiological responses to emotional stress. The present review focuses on angiotensin-(1-7)/Mas axis as a promising target to attenuate the physiological response to emotional stress reducing the risk of cardiovascular diseases.

Vascular risk factors aggravate the progression of Alzheimer's disease: a 3-year follow-up study of Chinese population

PURPOSE

To explore the correlation of vascular risk factors for Alzheimer's disease (AD) in Chinese population.

METHODS

A total of 123 outpatients with probable AD followed up for 3 years were investigated. Severity of cognitive impairment and functional ability was assessed using Mini-Mental State Examination (MMSE) and modified activities of daily living (ADLs), respectively. The incidence of vascular risk factors was studied in patients with AD.

RESULTS

Univariate analysis showed significance difference in MMSE and ADL scores between patients with and without vascular risk factors (P < .05). Multiple regression analysis showed age, education, hyperhomocysteinemia, and hypertension were significant variables associated with annual MMSE, while there were no significant correlations between annual MMSE and sex, initial MMSE, diabetes, and so on.

CONCLUSIONS

Vascular risk factors are common comorbidities in patients with AD in China, with younger, better educated ones showing faster cognitive decline. Hypertension and hyperhomocysteinemia may also aggravate the progression, and it is important to prevent and treat patients with AD.

Angiotensin type 1 receptor inhibition enhances the extinction of fear memory

BACKGROUND

The current effective treatment options for posttraumatic stress disorder (PTSD) are limited, and therefore the need to explore new treatment strategies is critical. Pharmacological inhibition of the renin-angiotensin system is a common approach to treat hypertension, and emerging evidence highlights the importance of this pathway in stress and anxiety. A recent clinical study from our laboratory provides evidence supporting a role for the renin-angiotensin system in the regulation of the stress response in patients diagnosed with PTSD.

METHODS

With an animal model of PTSD and the selective angiotensin receptor type 1 (AT1) antagonist losartan, we investigated the acute and long-term effects of AT1 receptor inhibition on fear memory and baseline anxiety. After losartan treatment, we performed classical Pavlovian fear conditioning pairing auditory cues with footshocks and examined extinction behavior, gene expression changes in the brain, as well as neuroendocrine and cardiovascular responses.

RESULTS

After cued fear conditioning, both acute and 2-week administration of losartan enhanced the consolidation of extinction memory but had no effect on fear acquisition, baseline anxiety, blood pressure, and neuroendocrine stress measures. Gene expression changes in the brain were also altered in mice treated with losartan for 2 weeks, in particular reduced amygdala AT1 receptor and bed nucleus of the stria terminalis c-Fos messenger RNA levels.

CONCLUSIONS

These data suggest that AT1 receptor antagonism enhances the extinction of fear memory and therefore might be a beneficial therapy for PTSD patients who have impairments in extinction of aversive memories.

Angiotensin and Alzheimer´s disease: therapeutic prospects

This review describes the features of Alzheimer's disease and discusses the evidence that antihypertensive therapies may be beneficial in its treatment and prevention. Drugs acting via the renin-angiotensin system are considered and it is suggested that these drugs may produce their effects via mechanisms other than by their antihypertensive actions. Using evidence from animal studies, the role of angiotensin as a neurotransmitter and its involvement in the control of normal cognitive function is described. Studies of angiotensin and human cognition are reviewed along with studies investigating the possible link between disorders of the system, either inherited or acquired, and the symptoms of Alzheimer's disease. The therapeutic potential of screening for markers of renin-angiotensin abnormality for the prediction of Alzheimer's disease is considered, as is the potential use of agents known to influence the renin-angiotensin system in the treatment or prevention of the disease.

Can bariatric surgery reduce risk of Alzheimer's disease?

Recent studies demonstrate that obesity is independently associated with poor neurocognitive outcomes, including cognitive impairment, increased risk for dementia, and regional alterations in brain structure. Bariatric surgery is an effective treatment for obesity and initial findings suggest that it may result in cognitive improvements. The current paper reviews and integrates recent research in this area, with a focus on potential mediators and moderators of neuropsychological outcome in bariatric surgery patients, including anesthetic and nutritional complications, and proposes novel avenues for continued study in this area.

A Comparison of Cognitive and Everyday Functional Performance among Older Adults With and Without Hypertension

Secondary data analyses examined the differences in cognitive and instrumental activities of daily living (IADL) performance among hypertensive individuals taking one of four classes of antihypertensive medications, hypertensive individuals not taking any antihypertensive medications, and normotensive individuals (N=770). After adjusting for covariates, significant group differences were evident on all measures (speed of processing, motor speed, reaction time, ps < .05) except memory and Timed IADL (ps > .05). Follow-up a priori planned comparisons compared hypertensive individuals not on medications to each of the four antihypertensive medication groups. Results indicated that only those on beta blockers (BB) were significantly slower in speed of processing (ps < .05). A priori planned comparisons also revealed that normotensive individuals had better cognitive performance on measures of processing speed, motor speed, and reaction time than hypertensive individuals regardless of antihypertensive medication use. Additionally, normotensive individuals performed significantly better on memory (Digit and Spatial Span) than individuals with hypertension on medications. No differences were found between groups on memory (Hopkins Verbal Learning Test) or Timed IADL performance. With regard to antihypertensive medications, the use of BBs was associated with slowed processing speed. These analyses provide empirical evidence that hypertension primarily impacts speed of processing, but not severe enough to affect IADL performance. Given the contribution of processing speed to memory and executive function performance, this is an important finding. Clinicians need to take into consideration the potential negative impact that BBs may have on cognition when determining the best treatment of hypertension among older adult patients.

Antemortem pulse pressure elevation predicts cerebrovascular disease in autopsy-confirmed Alzheimer's disease

Elevated pulse pressure (PP) is associated with cognitive decline and increased risk of Alzheimer's disease (AD) in older adults, although the mechanisms behind these associations remain unclear. To address this question, we examined whether antemortem late-life PP elevation predicted vascular or AD pathology in autopsy-confirmed AD patients. Sixty-five elderly patients (mean age 74.2 years) clinically diagnosed with possible or probable AD underwent neuropsychological testing and blood pressure examinations. Postmortem histopathological measures of cerebrovascular disease (CVD) and AD neuropathology were later obtained on these same patients. We expected that antemortem PP elevation, but not standard blood pressure measures such as systolic or diastolic blood pressure, would predict the autopsy-based presence of CVD, and possibly AD pathology, in elderly AD patients. Results demonstrated that antemortem PP elevation was associated with the presence and severity of CVD at autopsy. For every 5 mmHg increase in antemortem PP there was an estimated 36% increase in the odds of having CVD at autopsy. Additionally, PP accounted for 12% of variance in CVD severity. No significant associations were present for cerebral amyloid angiopathy or Braak and Braak staging of the severity of AD pathology. Other standard blood pressure measures also did not significantly predict neuropathology. The association between antemortem PP and CVD at autopsy suggests that in older adults with AD, PP elevation may increase the risk of CVD. These findings may have treatment implications since some antihypertensive medications specifically address the pulsatile component of blood pressure (e.g., renin-angiotensin system inhibitors, calcium channel blockers).

Cognitive decline and the default American lifestyle

OBJECTIVES

Upward trends in IQ, education, and mental work suggest that cognitive function among seniors should be rising strongly across cohorts. There is little sign of such improvement in recent decades, and some analyses find poorer function in the newer cohorts. This essay explores possible explanations of the anomaly.

METHODS

Major long-term trends that might increase cognitive impairment are reviewed, and their implications are considered.

RESULTS

Physical activity is declining, food is increasingly manufactured, body fat is increasing, diabetes and metabolic syndrome are on the rise, the number of prescription drugs per person is increasing, and the proportion of the population either old or obese is growing.

DISCUSSION

Technological and economic development may lower the cognitive function needed for survival. They also lower physical activity in daily life. Sedentary work, transportation, and leisure undermine the aerobic and metabolic fitness required for the brain to perform well. Some prescription drugs impair cognitive function, and others do so when taken for many years or in combination with others. The growing fraction of the population that is either old or obese may further lower physical activity norms and requirements and substitute medical intervention for health, accelerating a trend toward cognitive impairment.

Effect of phlorotannins isolated from Ecklonia cava on angiotensin I-converting enzyme (ACE) inhibitory activity

Inhibition of angiotensin I-converting enzyme (ACE) activity is the most common mechanism underlying the lowering of blood pressure. In the present study, five organic extracts of a marine brown seaweed Ecklonia cava were prepared by using ethanol, ethyl acetate, chloroform, hexane, and diethyl ether as solvents, which were then tested for their potential ACE inhibitory activities. Ethanol extract showed the strongest ACE inhibitory activity with an IC(50) value of 0.96 mg/ml. Five kinds of phlorotannins, phloroglucinol, triphlorethol-A, eckol, dieckol, and eckstolonol, were isolated from ethanol extract of E. cava, which exhibited potential ACE inhibition. Dieckol was the most potent ACE inhibitor and was found to be a non-competitive inhibitor against ACE according to Lineweaver-Burk plots. Dieckol had an inducible effect on the production of NO in EAhy926 cells without having cytotoxic effect. The results of this study indicate that E. cava could be a potential source of phlorotannins with ACE inhibitory activity for utilization in production of functional foods.

Cognitive impairment in common, noncentral nervous system medical conditions of adults and the elderly

Common, noncentral nervous system medical conditions linked with cognitive impairment in adults and the elderly include: acute respiratory distress syndrome; cancer; chronic kidney disease; chronic obstructive pulmonary disease; coronary heart disease; hypertension; obesity (bariatric surgical candidates); obstructive sleep apnea; and type 2 diabetes. Cross-condition comparison of the nature and frequency of cognitive impairment is difficult as these conditions often coexist, and there exists no consensus as to the definition of cognitive impairment, nor the optimal number and type of neuropsychological tests required for evaluation. There is as yet no clear evidence for condition-specific profiles of cognitive impairment. Rather, a generalized profile consisting of subclinical levels of impairment in attention, processing speed, executive, and memory functions from bilateral frontal-subcortical ischemia fits across all conditions. This profile: occurs only in subgroups of patients; is inconsistently related to measures of illness severity; is unrelated to patient self-report or level of functional independence; is exacerbated by very high levels of emotional distress; and is reversible in some cases but can also progress to frank neurological disease (dementia) in others, especially the elderly, when multiple conditions coexist, and/or when medical condition severity progresses.

Improved memory function 12 weeks after bariatric surgery

BACKGROUND

Growing evidence has shown that obesity is associated with poor neurocognitive outcomes. Bariatric surgery has been shown to be an effective intervention for morbid obesity and can result in improvement of many co-morbid medical conditions that are associated with cognitive dysfunction. The effects of bariatric surgery on cognition are unknown.

METHODS

We performed a prospective study total of 150 subjects (109 bariatric surgery patients enrolled in the Longitudinal Assessment of Bariatric Surgery project and 41 obese control subjects who had not undergone bariatric surgery). These 150 subjects completed a cognitive evaluation at baseline and at 12 weeks of follow-up. The demographic, medical, and psychosocial information was also collected to elucidate the possible mechanisms of change.

RESULTS

Many bariatric surgery patients exhibited impaired performance on cognitive testing at baseline (range 4.6-23.9%). However, the surgery patients were no more likely to exhibit a decline on ≥2 cognitive tests at 12 weeks of follow-up than were the obese controls [12.84% versus 23.26%; chi-square (1) = 2.51, P = .11]. Group comparisons using repeated measures multivariate analysis of variance showed that the surgery patients had improved memory performance at 12 weeks of follow-up [λ = .86, F(4, 147) = 5.88, P <.001]; however, the memory performance of the obese controls had actually declined. Regression analyses showed that the surgery patients without hypertension had better short delay recall at 12 weeks than those with hypertension [β = .31, P = .005], although the other demographic and medical variables were largely unrelated to the test performance.

CONCLUSION

The present results suggest that cognitive impairment is common in bariatric surgery patients, although these deficits might be at least partly reversible. Future studies are needed to clarify the underlying mechanisms, in particular, longitudinal studies using neuroimaging and blood markers.

AVR/NAVR deficiency lowers blood pressure and differentially affects urinary concentrating ability, cognition, and anxiety-like behavior in male and female mice

Arginine vasopressin (AVP) and angiotensin II (ANG II) are distinct peptide hormones involved in multiple organs modulating renal, cardiovascular, and brain functions. They achieve these functions via specific G protein-coupled receptors, respectively. The AVR/NAVR locus encodes two overlapping V2-type vasopressin isoreceptors: angiotensin-vasopressin receptor (AVR) responding to ANG II and AVP equivalently, and nonangiotensin vasopressin receptor (NAVR), which binds vasopressin exclusively. AVR and NAVR are expressed from a single gene by alternative promoter usage that is synergistically upregulated by testosterone and estrogen. This study tested the hypothesis that AVR/NAVR modulates urinary concentrating ability, blood pressure, and cognitive performance in vivo in a sex-specific manner. We developed a C57BL/6 inbred AVR/NAVR(-/-) knockout mouse that showed lower blood pressure in both male and female subjects and a urinary-concentrating defect restricted to male mice. We also detected sex-specific effects on cognitive and anxiety-like behaviors. AVR/NAVR(-/-) male mice exhibited impaired visuospatial and associative learning, while female mice showed improved performance in both type of cognition. AVR/NAVR deficiency produced an anxiolytic-like effect in female mice, while males were unaffected. Analysis of AVR- and NAVR-mediated phosphorylation/dephosphorylation of signaling proteins revealed activation/deactivation of known modulators of cognitive function. Our studies identify AVR/NAVR as key receptors involved in blood pressure regulation and sex-specific modulation of renal water homeostasis, cognitive function, and anxiety-like behavior. As such, the AVR/NAVR receptor system provides a molecular mechanism for sexually diergic traits and a putative common pathway for the emerging association of hypertension and cognitive decline and dementia.

Effects of health status on word finding in aging

OBJECTIVES

To evaluate effects of health status on word-finding difficulty in aging, adjusting for the known contributors of education, sex, and ethnicity.

DESIGN

Cross-sectional.

SETTING

Community.

PARTICIPANTS

Two hundred eighty-four adults aged 55 to 85 (48.6% female) participating in an ongoing longitudinal study of language in aging.

MEASUREMENTS

Medical, neurological, and laboratory evaluations to determine health status and presence or absence of hypertension and diabetes mellitus. Lexical retrieval evaluated with the Boston Naming Test (BNT) and Action Naming Test.

RESULTS

Unadjusted regression models showed that presence of diabetes mellitus was not related to naming. Presence of hypertension was associated with significantly lower accuracy on both tasks (P<.02). Adjustment for demographics attenuated the effect of hypertension (P<.08). For the BNT, a variable combining presence, treatment, and control of hypertension was marginally significant (P<.10), with subjects with uncontrolled hypertension being least accurate (91.4%). Previously observed findings regarding the effects of age, education, sex, and ethnicity were confirmed.

CONCLUSION

In this sample of older adults, hypertension contributed to the word-finding difficulty of normal aging, but diabetes mellitus did not.

Effects of health status on word finding in aging

OBJECTIVES

To evaluate effects of health status on word-finding difficulty in aging, adjusting for the known contributors of education, sex, and ethnicity.

DESIGN

Cross-sectional.

SETTING

Community.

PARTICIPANTS

Two hundred eighty-four adults aged 55 to 85 (48.6% female) participating in an ongoing longitudinal study of language in aging.

MEASUREMENTS

Medical, neurological, and laboratory evaluations to determine health status and presence or absence of hypertension and diabetes mellitus. Lexical retrieval evaluated with the Boston Naming Test (BNT) and Action Naming Test.

RESULTS

Unadjusted regression models showed that presence of diabetes mellitus was not related to naming. Presence of hypertension was associated with significantly lower accuracy on both tasks (P<.02). Adjustment for demographics attenuated the effect of hypertension (P<.08). For the BNT, a variable combining presence, treatment, and control of hypertension was marginally significant (P<.10), with subjects with uncontrolled hypertension being least accurate (91.4%). Previously observed findings regarding the effects of age, education, sex, and ethnicity were confirmed.

CONCLUSION

In this sample of older adults, hypertension contributed to the word-finding difficulty of normal aging, but diabetes mellitus did not.

Reinventing the ACE inhibitors: some old and new implications of ACE inhibition

Since their inception, angiotensin-converting enzyme (ACE) inhibitors have been used as first-line therapy for the treatment of cardiovascular and renal diseases. They restore the balance between the vasoconstrictive salt-retentive and hypertrophy-causing peptide angiotensin II (Ang II) and bradykinin, a vasodilatory and natriuretic peptide. As ACE is a promiscuous enzyme, ACE inhibitors alter the metabolism of a number of other vasoactive substances. ACE inhibitors decrease systemic vascular resistance without increasing heart rate and promote natriuresis. They have been proven effective in the treatment of hypertension, and reduce mortality in congestive heart failure and left ventricular dysfunction after myocardial infarction. They inhibit ischemic events and stabilize plaques. Furthermore, they delay the progression of diabetic nephropathy and neuropathy and act as antioxidants. Ongoing studies have elucidated protective roles for them in both memory-related disorders and cancer. Lastly, N- and C-domain selective ACE inhibitors have led to new uses for ACE inhibitors.

Angiotensin-converting enzyme inhibitors and cognitive decline in older adults with hypertension: results from the Cardiovascular Health Study

BACKGROUND

Hypertension (HTN) is a risk factor for dementia, and animal studies suggest that centrally active angiotensin-converting enzyme (ACE) inhibitors (those that cross the blood-brain barrier) may protect against dementia beyond HTN control.

METHODS

Participants in the Cardiovascular Health Study Cognition Substudy with treated HTN and no diagnosis of congestive heart failure (n = 1054; mean age, 75 years) were followed up for a median of 6 years to determine whether cumulative exposure to ACE inhibitors (as a class and by central activity), compared with other anti-HTN agents, was associated with a lower risk of incident dementia, cognitive decline (by Modified Mini-Mental State Examination [3MSE]), or incident disability in instrumental activities of daily living (IADLs).

RESULTS

Among 414 participants who were exposed to ACE inhibitors and 640 who were not, there were 158 cases of incident dementia. Compared with other anti-HTN drugs, there was no association between exposure to all ACE inhibitors and risk of dementia (hazard ratio [HR], 1.01; 95% confidence interval [CI], 0.88-1.15), difference in 3MSE scores (-0.32 points per year; P = .15), or odds of disability in IADLs (odds ratio [OR], 1.06; 95% CI, 0.99-1.14). Adjusted results were similar. However, centrally active ACE inhibitors were associated with 65% less decline in 3MSE scores per year of exposure (P = .01), and noncentrally active ACE inhibitors were associated with a greater risk of incident dementia (adjusted HR, 1.20; 95% CI, 1.00-1.43 per year of exposure) and greater odds of disability in IADLs (adjusted OR, 1.16; 95% CI, 1.03-1.30 per year of exposure) compared with other anti-HTN drugs.

CONCLUSIONS

While ACE inhibitors as a class do not appear to be independently associated with dementia risk or cognitive decline in older hypertensive adults, there may be within-class differences in regard to these outcomes. These results should be confirmed with a randomized clinical trial of a centrally active ACE inhibitor in the prevention of cognitive decline and dementia.

Nicardipine: a hypotensive dihydropyridine-type calcium antagonist with a peculiar cerebrovascular profile

Control of blood pressure protects against the development of cerebrovascular lesions, stroke, and vascular dementia (VaD). Cerebrovascular disease is increasingly recognized as a cause of cognitive impairment and dementia primarily in the elderly. Nicardipine is a dihydropyridine-type calcium channel blocker (CCB) with a peculiar cerebrovascular profile developed approximately 30 years ago. This study has reviewed the main controlled clinical studies investigating the use of nicardipine in pathologies associated with cerebrovascular injury, such as subarachnoid haemorrhage (SAH), acute stroke, and VaD. SAH is a main cerebrovascular indication of CCBs. In this indication, CCBs prevent vasospasm and improve clinical outcomes. Nimodipine represents the CCB more investigated in this indication. Former studies did not demonstrate a clear advantage of nicardipine versus nimodipine in SAH. A more recent approach using implants of nicardipine prolonged-release showed a decreased incidence of vasospasm, delayed ischemic deficits, and improved clinical outcome after severe SAH. Controlled trials have shown the effectiveness of the drug in preventing stroke. Increasing evidence suggests some benefit of some CCBs in VaD or mixed degenerative and vascular dementia. In this setting, nicardipine has been investigated in approximately 6,000 patients, with an improvement of cognitive deterioration in more than 60% of patients treated. The pronounced anti-hypertensive activity of nicardipine and its safety and effectiveness in cognitive domain suggest its reconsideration in the treatment of cognitive impairment of vascular origin as well as for reducing the risk of recurrent stroke in patients at high risk of it.

Ang II and Ang IV: unraveling the mechanism of action on synaptic plasticity, memory, and epilepsy

The central angiotensin system plays a crucial role in cardiovascular regulation. More recently, angiotensin peptides have been implicated in stress, anxiety, depression, cognition, and epilepsy. Angiotensin II (Ang II) exerts its actions through AT(1) and AT(2) receptors, while most actions of its metabolite Ang IV were believed to be independent of AT(1) or AT(2) receptor activation. A specific binding site with high affinity for Ang IV was discovered and denominated "AT(4) receptor". The beneficiary effects of AT(4) ligands in animal models for cognitive impairment and epileptic seizures initiated the search for their mechanism of action. This proved to be a challenging task, and after 20 years of research, the nature of the "AT(4) receptor" remains controversial. Insulin-regulated aminopeptidase (IRAP) was first identified as the high-affinity binding site for AT(4) ligands. Recently, the hepatocyte growth factor receptor c-MET was also proposed as a receptor for AT(4) ligands. The present review focuses on the effects of Ang II and Ang IV on synaptic transmission and plasticity, learning, memory, and epileptic seizure activity. Possible interactions of Ang IV with the classical AT(1) and AT(2) receptor subtypes are evaluated, and other potential mechanisms by which AT(4) ligands may exert their effects are discussed. Identification of these mechanisms may provide a valuable target in the development in novel drugs for the treatment of cognitive disorders and epilepsy.

Cognitive-enhancing effects of angiotensin IV

Angiotensin IV is a derivative of the potent vasoconstrictor angiotensin II and it has been shown to enhance acquisition, consolidation and recall in animal models of learning and memory when administered centrally or peripherally. Whether changes in angiotensin IV activity underlie the cognitive effects of those cardiovascular drugs designed to disrupt the peripheral renin-angiotensin system in humans remains undetermined, but angiotensin IV appears to be a worthy candidate for consideration in drug development programmes. The mechanism of action of angiotensin IV is still debated, although its AT₄ receptor has been convincingly identified as being insulin-regulated amino peptidase, which is also known as oxytocinase and placental leucine aminopeptidase. It is speculated that angiotensin IV may interact with insulin-regulated amino peptidase to enhance neuronal glucose uptake, prevent metabolism of other neuroactive peptides, induce changes in extracellular matrix molecules, or induce release of acetylcholine and/or dopamine. All of these things may be responsible for the beneficial effects on cognition, but none of them are yet proven. Importantly, strain differences in murine responses to angiotensin IV suggest that some individuals may benefit from drugs targeted to the AT₄ receptor whilst others may be refractory. At present it thus appears that those individuals with the poorest baseline cognition may receive greatest benefit, but possible genetic differences in responses to angiotensin IV cannot be ruled-out.

Assessment of patients with mild concussion in the emergency department

OBJECTIVES

(1) To test the validity of the Standardized Assessment of Concussion (SAC) in characterizing the early evolution of concussion-related symptoms and mental status changes in the emergency department (ED) setting and (2) to compare it to the Conner's Continuous Performance Test 2nd Edition (CPT-II).

DESIGN

Prospective within-subject (repeated measures) design.

PARTICIPANTS

Sixty-two persons with concussion (Glasgow Coma Scale = 15) and negative head computed tomographic scan results were examined on arrival in the ED and 3 and 6 hours later.

SETTING

A large urban, tertiary medical center ED.

MAIN OUTCOME MEASURES

SAC; CPT-II; Post-Concussion Symptom Scale-Revised (PCS-R).

RESULTS

SAC and CPT-II scores improved significantly over the time course in the ED. Symptoms did not correlate with improvement, with many subjects complaining of headache or nausea after their scores improved. The average initial score on the SAC was 21 +/- 5.4/30.

CONCLUSION

The SAC appears sensitive to the acute changes following concussion. It may be a useful tool for clinicians in detecting mental status changes after a concussion, when Glasgow Coma Scale and radiologic findings are normal.

Rationale, design and methods of the OSCAR study: observational study on cognitive function and systolic blood pressure reduction in hypertensive patients

Data from several recent clinical trials have suggested a beneficial effect of antihypertensive medications on preservation of cognitive function. Eprosartan, an angiotensin type-1 receptor antagonist (ARA) with dual action on both pre- and postsynaptic angiotensin type 1 receptors, may be effective in the control of SBP and the prevention of cognitive decline. The OSCAR (Observational Study on Cognitive function And SBP Reduction) study is an international longitudinal observational study with a duration of 6 months intended to examine the impact of the ARA eprosartan on cognitive function (assessed using the Mini-Mental State Examination [MMSE]) and control of systolic blood pressure (SBP) in a large international population of hypertensive patients managed in a standard primary care setting. A total of 100,000 hypertensive patients, aged >or=50 years and with SBP of >140 mmHg will be recruited by more than 20 000 primary care physicians in 27 countries. These patients will receive eprosartan 600 mg once a day for 6 months. The MMSE, a globally validated cognitive screening test, will be performed at baseline, and after 6 months of treatment. After the first month of monotherapy, eprosartan treatment may, at the absolute discretion of individual investigators, be supplemented with other antihypertensive medications for the remainder of the study. The primary outcome indices are the mean relative change in MMSE score and the absolute change from baseline in SBP in the study population as a whole and in subsets of patients according to various factors among them: ethnicity, comorbidities (i.e. target organ damage, diabetes), baseline cognitive level and baseline blood pressure level. The secondary objectives are to identify factors influencing SBP and MMSE changes. The OSCAR trial is the first international observational study focusing on MMSE in a wide international cohort of hypertensive patients. The results are expected in 2007.

Effect of chronic angiotensin converting enzyme inhibition on spatial memory and anxiety-like behaviours in rats

Angiotensin converting enzyme inhibitors (ACEis) are widely used anti-hypertensive agents that are also reported to have positive effects on mood and cognition. The present study examined the influence of the ACEi, perindopril, on cognitive performance and anxiety measures in rats. Two groups of rats were treated orally for one week with the ACEi, perindopril, at doses of 0.1 and 1.0mg/kg/day. Learning was assessed by the reference memory task in the water maze, comparing treated to control rats. Over five training days both perindopril-treated groups learnt the location of the submerged platform in the water maze task significantly faster than control rats. A 60s probe trial on day 6 showed that the 1.0mg/kg/day group spent significantly longer time in the training quadrant than control rats. This improved performance in the swim maze task was not due to the effect of perindopril on motor activity or the anxiety levels of the rats as perindopril-treated and control animals behaved similarly in activity boxes and on the elevated+maze. These results confirm the anecdotal human studies that ACEis have a positive influence on cognition and provide possibilities for ACEis to be developed into therapies for memory loss.

Angiotensin II: multitasking in the brain

In addition to controlling systemic blood pressure, angiotensin II (Ang II) has several roles in the brain, including the regulation of cerebrovascular flow and the reaction to stress. In order to clarify the central effects of Ang II and its type 1 (AT1) receptors, we reviewed the literature reporting recent research on the effects of pretreatment with the AT1-receptor blocker, candesartan, on experimental ischemia, cerebrovascular remodeling, and inflammation in spontaneously hypertensive rats (SHRs), and the responses to stress induced by isolation and by cold-restraint. Angiotensin II regulates the brain circulation through stimulation of AT1-receptors located in the cerebrovascular endothelium and central pathways. SHRs express greater numbers of endothelial AT1-receptors and a central sympathetic overdrive, resulting in pathological cerebrovascular growth, inflammation, decreased cerebrovascular compliance, and enhanced vulnerability to brain ischemia. Sustained central AT1-receptor antagonism reverses these effects. Sustained reduction of AT1-receptor stimulation before stress prevents the hormonal and sympathoadrenal stress responses during isolation and prevents the gastric ulceration stress response to cold-restraint, indicating that increased AT1-receptor stimulation is essential to enhance the central sympathetic response and the formation and release of corticotropin-releasing factor (CRF) and arginine vasopressin that occur during stress. AT1-receptor blocking agents reverse the cortical alterations in CRF1 and benzodiazepine receptors characteristic of isolation stress, effects probably related to their anti-anxiety effect in rodents. Sustained reduction of Ang II tone by AT1-receptor antagonism could be considered as a preventive and therapeutic approach for brain ischemia and stress-related and mood disorders. Additional preclinical studies and controlled clinical trials are necessary to confirm the efficacy of this novel therapeutic approach.

The effects of blood pressure lowering on development of cognitive impairment and dementia in patients without apparent prior cerebrovascular disease

BACKGROUND

Hypertension and cognitive impairment are prevalent in older people. It is known that hypertension is a direct risk factor for vascular dementia and recent studies have suggested hypertension also impacts upon prevalence of Alzheimer's disease. The question is therefore whether treatment of hypertension lowers the rate of cognitive decline.

OBJECTIVES

To assess the effects of blood pressure lowering treatments for the prevention of dementia and cognitive decline in patients with hypertension but no history of cerebrovascular disease.

SEARCH STRATEGY

The trials were identified through a search of CDCIG's Specialised Register, CENTRAL, MEDLINE, EMBASE, PsycINFO and CINAHL on 27 April 2005.

SELECTION CRITERIA

Randomized, double-blind, placebo controlled trials in which pharmacological or non-pharmacological interventions to lower blood pressure were given for at least six months.

DATA COLLECTION AND ANALYSIS

Two independent reviewers assessed trial quality and extracted data. The following outcomes were assessed: incidence of dementia, cognitive change from baseline, blood pressure level, incidence and severity of side effects and quality of life.

MAIN RESULTS

Three trials including 12,091 hypertensive subjects were identified. Average age was 72.8 years. Participants were recruited from industrialised countries. Mean blood pressure at entry across the studies was 170/84 mmHg. All trials instituted a stepped care approach to hypertension treatment, starting with a calcium-channel blocker, a diuretic or an angiotensin receptor blocker. The combined result of the three trials reporting incidence of dementia indicated no significant difference between treatment and placebo (Odds Ratio (OR) = 0.89, 95% CI 0.69, 1.16). Blood pressure reduction resulted in a 11% relative risk reduction of dementia in patients with no prior cerebrovascular disease but this effect was not statistically significant (p = 0.38) and there was considerable heterogeneity between the trials. The combined results from the two trials reporting change in Mini Mental State Examination (MMSE) did not indicate a benefit from treatment (Weighted Mean Difference (WMD) = 0.10, 95% CI -0.03, 0.23). Both systolic and diastolic blood pressure levels were reduced significantly in the two trials assessing this outcome (WMD = -7.53, 95% CI -8.28, -6.77 for systolic blood pressure, WMD = -3.87, 95% CI -4.25, -3.50 for diastolic blood pressure). Two trials reported adverse effects requiring discontinuation of treatment and the combined results indicated a significant benefit from placebo (OR = 1.18, 95% CI 1.06, 1.30). When analysed separately, however, more patients on placebo in SCOPE were likely to discontinue treatment due to side effects; the converse was true in SHEP 1991. Quality of life data could not be analysed in the three studies. There was difficulty with the control group in this review as many of the control subjects received antihypertensive treatment because their blood pressures exceeded pre-set values. In most cases the study became a comparison between the study drug against a usual antihypertensive regimen.

AUTHORS' CONCLUSIONS

There was no convincing evidence from the trials identified that blood pressure lowering prevents the development of dementia or cognitive impairment in hypertensive patients with no apparent prior cerebrovascular disease. There were significant problems identified with analysing the data, however, due to the number of patients lost to follow-up and the number of placebo patients given active treatment. This introduced bias. More robust results may be obtained by analysing one year data to reduce differential drop-out or by conducting a meta-analysis using individual patient data.

Effects of age and hypertension status on cognition: the Veterans Affairs Normative Aging Study

The authors examined the influence of age and hypertensive status (normotensive, controlled, untreated, or uncontrolled) on several cognitive tests via multiple regression in 357 nondemented, community-dwelling older men (mean age=67 years) whose hypertensive status was stable over 3 years and who had no medical comorbidities. Age was negatively associated with performance on all but 1 test. Age interacted with hypertensive status on verbal fluency and word list immediate recall; older uncontrolled hypertensives exhibited significantly larger age decrements on these tests compared with normotensives. These findings suggest that uncontrolled hypertension produces specific cognitive deficits beyond those attributable to age alone. These and previous findings illustrate that health conditions such as hypertension should be regularly considered in studies of "normal" cognitive aging.

Diagnosis of hypertension and high blood pressure levels negatively affect cognitive function in older adults

BACKGROUND

Hypertension is associated with diminished performance on tests of cognitive function. The degree to which those diagnosed with hypertension have controlled blood pressure (BP) levels may be a critical determinant of cognitive outcomes. Persons with hypertension and poorly controlled BP are likely to display the worst performance on cognitive tests.

PURPOSE

The purpose is to examine potential interactive relations of hypertension diagnostic status and current BP levels to cognitive function.

METHODS

Participants were 101 healthy older adults (ages 53-84, 62% male, 90% White, 29% diagnosed with hypertension) who engaged in biomedical and neuropsychological assessment.

RESULTS

After statistical adjustment for age and education, persons with high BP performed more poorly than those with normal BP on the Visual Reproductions-Immediate and Delayed Recall and the Grooved Pegboard tests. Diagnosed hypertension was related to poorer performance on the Grooved Pegboard tests. An interaction of diagnosed hypertension and BP level revealed that those diagnosed with hypertension and also having poorly controlled BP levels performed least well on the Grooved Pegboard tests and the Trail Making Test-Part A.

CONCLUSION

Irrespective of prior diagnostic status, individuals with high BP displayed compromised performance on tests of nonverbal memory, motor speed, and manual dexterity. However, as compared to the other groups, those diagnosed with hypertension and also having poorly controlled BP elevation were most vulnerable to difficulties on tests of perceptuo-motor speed, motor speed, and manual dexterity. These findings suggest the need for increased attention to preventative efforts with respect to BP assessment and control in older adults to help preserve cognitive function.

Angiotensin as a target for the treatment of Alzheimer’s disease, anxiety and depression

The brain renin-angiotensin system (RAS), which is comprised of a variety of peptides including angiotensin II, angiotensin III and angiotensin IV acting on AT<inf>1</inf>, AT<inf>2</inf> and AT<inf>4</inf> receptors, is important in cognition and anxiety. Perturbation of the RAS improves basal cognition and reverses age-, scopolamine-, ethanol- and diabetes-induced deficits. In studies of dementias and Alzheimer's disease (AD), some studies have shown that antihypertensive drugs, including angiotensin-converting enzyme inhibitors, have some moderate effects on cognitive decline, but that the angiotensin receptor antagonist losartan has a significantly beneficial effect. These findings suggest that angiotensin receptor ligands may have potential in the prevention or even reversal of vascular dementias and AD. With respect to depression and anxiety, there is similar experimental evidence from animal models that drugs acting on the RAS may be antidepressant or anxiolytic, but insufficient clinical data exist. Such effects, if proven, could promote the use of such agents in the treatment of hypertension coexisting with depression or anxiety.