Calcium channel blockers and risk of AD: the Baltimore Longitudinal Study of Aging

Hypertension & dementia: Pathophysiology & potential utility of antihypertensives in reducing disease burden

Dementia is a common cause of disability and dependency among the elderly due to its progressive neurodegenerative nature. As there is currently no curative therapy, it is of major importance to identify new ways to reduce its prevalence. Hypertension is recognised as a modifiable risk factor for dementia, particularly for the two most common subtypes; vascular dementia (VaD) and Alzheimer's disease (AD). From the current literature, identified through a comprehensive literature search of PubMed and Cochrane Library, this review aims to establish the stage in adulthood when hypertension becomes a risk for cognitive decline and dementia, and whether antihypertensive treatment is effective as a preventative therapy. Observational studies generally found hypertension in mid-life (age 45-64) to be correlated with an increased risk of cognitive decline and dementia incidence, including both VaD and AD. Hypertension manifesting in late life (age ≥ 65) was demonstrated to be less of a risk, to the extent that incidences of high blood pressure (BP) in the very elderly (age ≥ 75) may even be related to reduced incidence of dementias. Despite the evidence linking hypertension to dementia, there were conflicting findings as to whether the use of antihypertensives was beneficial for its prevention and this conflicting evidence and inconsistent results could be due to the methodological differences between the reviewed observational and randomised controlled trials. Furthermore, dihydropyridine calcium channel blockers and potassium-sparing diuretics were proposed to have neuroprotective properties in addition to BP lowering. Overall, if antihypertensives are confirmed to be beneficial by larger-scale homogenous trials with longer follow-up durations, treatment of hypertension, particularly in mid-life, could be an effective strategy to considerably lower the prevalence of dementia. Furthermore, greater clarification of the neuroprotective properties that some antihypertensives possess will allow for better clinical practice guidance on the choice of antihypertensive class for both BP lowering and dementia prevention.

L-type calcium channel antagonist isradipine age-dependently decreases plaque associated dystrophic neurites in 5XFAD mouse model

Epidemiological studies suggest that L-type calcium channel (LTCC) antagonists may reduce the incidence of age-associated neurodegenerative diseases including Alzheimer's disease (AD). However, the neuroprotective mechanism of LTCC antagonists is unknown. Amyloid-β (Aβ) pathology disrupts intracellular calcium signaling, which regulates lysosomes and microglial responses. Neurons near Aβ plaques develop dystrophic neurites, which are abnormal swellings that accumulate lysosomes. Further, microglia accumulate around Aβ plaques and secrete inflammatory cytokines. We hypothesized that antagonism of LTCCs with isradipine would reduce Aβ plaque-associated dystrophic neurites and inflammatory microglia in the 5XFAD mouse model by restoring normal intracellular calcium regulation. To test this hypothesis, we treated 6- and 9-month-old 5XFAD mice with isradipine and tested behavior, examined Aβ plaques, microglia, and dystrophic neurites. We found that isradipine treatment age-dependently reduces dystrophic neurites and leads to trending decreases in Aβ but does not modulate plaque associated microglia regardless of age. Our findings provide insight into how antagonizing LTCCs alters specific cell types in the Aβ plaque environment, providing valuable information for potential treatment targets in future AD studies.

Angiotensin II Receptor Blockers Reduce Tau/Aß42 Ratio: A Cerebrospinal Fluid Biomarkers’ Case-Control Study

(1) Background: The role of antihypertensives in Alzheimer’s Disease (AD) prevention is controversial. This case-control study aims to assess whether antihypertensive medication has a protective role by studying its association with amyloid and tau abnormal levels. Furthermore, it suggests a holistic view of the involved pathways between renin-angiotensin drugs and the tau/amyloidß42 ratio (tau/Aß42 ratio); (2) Methods: The medical records of the participant patients were reviewed, with a focus on prescribed antihypertensive drugs and clinical variables, such as arterial blood pressure. The Anatomical Therapeutic Chemical classification was used to classify each drug. The patients were divided into two groups: patients with AD diagnosis (cases) and cognitively healthy patients (control); (3) Results: Age and high systolic blood pressure are associated with a higher risk of developing AD. In addition, combinations of angiotensin II receptor blockers are associated with a 30% lower t-tau/Aß42 ratio than plain angiotensin-converting enzyme inhibitor consumption; (4) Conclusions: Angiotensin II receptor blockers may play a potential role in neuroprotection and AD prevention. Likewise, several mechanisms, such as the PI3K/Akt/GSK3ß or the ACE1/AngII/AT1R axis, may link cardiovascular pathologies and AD presence, making its modulation a pivotal point in AD prevention. The present work highlights the central pathways in which antihypertensives may affect the presence of pathological amyloid and tau hyperphosphorylation.

Antihypertensive medication classes and the risk of dementia over a decade of follow-up

INTRODUCTION

Use of angiotensin II (ATII)-stimulating antihypertensive medication (AHM), including angiotensin receptor blockers (ARBs) and dihydropyridine calcium channel blockers (CCBs), has been associated with lower dementia risk. Previous studies had relatively short follow-up periods. The aim of this study is to investigate if these effects are sustained over longer periods.

METHODS

This post hoc observational analysis was based on data from a dementia prevention trial (preDIVA and its observational extension), among Dutch community-dwelling older adults without prior diagnosis of dementia. Differential associations between AHM classes and incident dementia were studied after 7.0 and 10.4 years, based on the median follow-up durations of dementia cases and all participants.

RESULTS

After 7 years, use of ATII-stimulating antihypertensives [hazard ratio = 0.68, 95% confidence interval (CI) = 0.47-1.00], ARBs (hazard ratio = 0.54, 95% CI = 0.31-0.94) and dihydropyridine CCBs (hazard ratio = 0.52, 95% CI = 0.30-0.91) was associated with lower dementia risk. After 10.4 years, associations for ATII-stimulating antihypertensives, ARBs and dihydropyridine CCBs attenuated (hazard ratio = 0.80, 95% CI = 0.61-1.04; hazard ratio = 0.75, 95% CI = 0.53-1.07; hazard ratio = 0.73, 95% CI = 0.51-1.04 respectively), but still suggested lower dementia risk when compared with use of other AHM classes. Results could not be explained by competing risk of mortality.

CONCLUSION

Our results suggest that use of ARBs, dihydropyridine CCBs and ATII-stimulating antihypertensives is associated with lower dementia risk over a decade, although associations attenuate over time. Apart from methodological aspects, differential effects of antihypertensive medication classes on incident dementia may in part be temporary, or decrease with ageing.

Effects of Hypertension on Alzheimer's Disease and Related Disorders

PURPOSE OF REVIEW

To review the pathophysiology of hypertension in Alzheimer's disease and related dementias and explore the current landscape of clinical trials involving treatment of hypertension to improve cognition.

RECENT FINDINGS

Hypertension is increasingly recognized as a contributor to cognitive impairment. Clinical trials that explore blood pressure reductions with cognitive outcomes have been promising. Various antihypertensives have been evaluated in clinical trials, with growing interest in those agents that impact the renin-angiotensin-aldosterone system due to its own association with cognitive impairment. No antihypertensive agent has been found to be superior to others in reducing cognitive impairment risk or conferring neuroprotective benefits. In this review, the pathophysiology of and clinical trial data involving hypertension and dementia will be explored. Hypertension is a significant risk factor for the development of neurodegenerative dementias, and clinical trials have been overall favorable in improving cognition by reductions in blood pressure using antihypertensive agents.

Protofibrillar Amyloid Beta Modulation of Recombinant hCaV2.2 (N-Type) Voltage-Gated Channels

Cav2.2 channels are key regulators of presynaptic Ca²⁺ influx and their dysfunction and/or aberrant regulation has been implicated in many disease states; however, the nature of their involvement in Alzheimer's disease (AD) is less clear. In this short communication, we show that recombinant hCav2.2/b_1b/a₂d₁ channels are modulated by human synthetic AD-related protofibrillar amyloid beta Ab_1-42 peptides. Structural studies revealed a time-dependent increase in protofibril length, with the majority of protofibrils less than 100 nm at 24 h, while at 48 h, the majority were longer than 100 nm. Cav2.2 modulation by Ab_1-42 was different between a 'low' (100 nM) and 'high' (1 µM) concentration in terms of distinct effects on individual biophysical parameters. A concentration of 100 nM Ab_1-42 caused no significant changes in the measured biophysical properties of Cav2.2 currents. In contrast, 1 µM Ab_1-42 caused an inhibitory decrease in the current density (pA/pF) and maximum conductance (Gmax), and a depolarizing shift in the slope factor (k). These data highlight a differential modulation of Cav2.2 channels by the Ab_1-42 peptide. Discrete changes in the presynaptic Ca²⁺ flux have been reported to occur at an early stage of AD; therefore, this study reveals a potential mechanistic link between amyloid accumulation and Ca_v2.2 channel modulation.

Novel Polyhydroquinoline-Hydrazide-Linked Schiff's Base Derivatives: Multistep Synthesis, Antimicrobial, and Calcium-Channel-Blocking Activities

Polyhydroquinoline (PHQ) are the unsymmetrical Hantzsch derivatives of 1,4-dihydropyridines with several biological applications. In this work, twenty-five (3-27) new Schiff's base derivatives of polyhydroquinoline hydrazide were synthesized in excellent to good yields by a multi-component reaction. The structures of the synthesized products (1-27) were deduced with the help of spectroscopic techniques, such as 1H-, 13C -NMR, and HR-ESI-MS. The synthesized products (1-27) were tested for their antibacterial and in vitro calcium -channel-blocking (CCB) potentials using the agar-well diffusion method, and isolated rat aortic ring preparations, respectively. Among the series, sixteen compounds were found to inhibit the growth of Escherichia coli and Enterococcus faecalis. Among them, compound 17 was observed to be the most potent one at a dose 2 µg/mL, with an 18 mm zone of inhibition against both bacteria when it was compared with the standard drug amoxicillin. Eight compounds showed CCB activity of variable potency; in particular, compound 27 was more potent, with an EC50 value of 0.7 (0.3-1.1) µg/mL, indicating their CCB effect.

Post-Translational Modification of Cav1.2 and its Role in Neurodegenerative Diseases

Cav1.2 plays an essential role in learning and memory, drug addiction, and neuronal development. Intracellular calcium homeostasis is disrupted in neurodegenerative diseases because of abnormal Cav1.2 channel activity and modification of downstream Ca²⁺ signaling pathways. Multiple post-translational modifications of Cav1.2 have been observed and seem to be closely related to the pathogenesis of neurodegenerative diseases. The specific molecular mechanisms by which Cav1.2 channel activity is regulated remain incompletely understood. Dihydropyridines (DHPs), which are commonly used for hypertension and myocardial ischemia, have been repurposed to treat PD and AD and show protective effects. However, further studies are needed to improve delivery strategies and drug selectivity. Better knowledge of channel modulation and more specific methods for altering Cav1.2 channel function may lead to better therapeutic strategies for neurodegenerative diseases.

Blood Pressure Levels and Risks of Dementia: a Nationwide Study of 4.5 Million People

There are inconsistent results on the impacts of controlling blood pressure (BP) on the risk of dementia. We investigated the association between BP and risk of dementia subtypes by antihypertensive treatment and comorbidities. Using the Korean National Health Insurance Service-Health Screening Database from 2009 to 2012, a total of 4 522 447 adults aged 60+ years without a history of dementia were analyzed and followed up for a mean of 5.4 years. Individuals were classified according to their baseline systolic BP (SBP) and diastolic BP; SBP 130 to <140 mm Hg and diastolic BP 80 to <90 mm Hg were used as reference groups. The risk of overall dementia and probable Alzheimer disease was significantly higher in the SBP≥160 and lower SBP groups. These U-shaped associations were consistent regardless of antihypertensive use or comorbidities. The risk of probable vascular dementia (VaD) was not higher among lower SBP groups and increased gradually as SBP increased. Although there was a linear association between SBP and the risk of probable VaD in individuals not taking antihypertensives or without comorbidities, there was a U-shaped association in individuals taking antihypertensives or with comorbidities. Patterns of association between diastolic BP and risk of probable Alzheimer disease or probable VaD were similar to those with SBP, except for the risk of probable VaD in individuals taking antihypertensives. In conclusion, risks of probable Alzheimer disease and probable VaD were different among lower BP groups. Although the risk of dementia appears higher in people with lower BP receiving antihypertensives, this finding may be affected by comorbidities.

Burden and correlates of cognitive impairment among hypertensive patients in Tanzania: a cross-sectional study

BACKGROUND

The evolution of cognitive impairment of vascular origin is increasingly becoming a prominent health threat particularly in this era where hypertension is the leading contributor of global disease burden and overall health loss. Hypertension is associated with the alteration of the cerebral microcirculation coupled by unfavorable vascular remodeling with consequential slowing of mental processing speed, reduced abstract reasoning, loss of linguistic abilities, and attention and memory deficits. Owing to the rapidly rising burden of hypertension in Tanzania, we sought to assess the prevalence and correlates of cognitive impairment among hypertensive patients attending a tertiary cardiovascular hospital in Tanzania.

METHODOLOGY

A hospital-based cross-sectional study was conducted at Jakaya Kikwete Cardiac Institute, a tertiary care public teaching hospital in Dar es Salaam, Tanzania between March 2020 and February 2021. A consecutive sampling method was utilized to recruit consented hypertensive outpatients during their scheduled clinic visit. General Practitioner Assessment of Cognition (GPCOG) Score was utilized in the assessment of cognitive functions. All statistical analyses utilized STATA v11.0 software. Pearson Chi square and Student's T-test were used to compare categorical and continuous variables respectively. Logistic regression analyses were used to assess for factors associated with cognitive impairment. Odd ratios with 95% confidence intervals and p-values are reported. All tests were 2-sided and p < 0.05 was used to denote a statistical significance.

RESULTS

A total of 1201 hypertensive patients were enrolled in this study. The mean age was 58.1 years and females constituted nearly two-thirds of the study population. About three quarters had excess body weight, 16.6% had diabetes, 7.7% had history of stroke, 5.7% had heart failure, 16.7% had renal dysfunction, 53.7% had anemia, 27.7% had hypertriglyceridemia, 38.5% had elevated LDL, and 2.4% were HIV-infected. Nearly two-thirds of participants had uncontrolled blood pressure and 8.7% had orthostatic hypotension. Overall, 524 (43.6%) of participants had cognitive impairment. During bivariate analysis in a logistic regression model of 16 characteristics, 14 parameters showed association with cognitive functions. However, after controlling for confounders, multivariate analysis revealed ≤primary education (OR 3.5, 95%CI 2.4-5.2, p < 0.001), unemployed state (OR 1.7, 95%CI 1.2-2.6, p < 0.01), rural habitation (OR 1.8, 95%CI 1.1-2.9, p = 0.01) and renal dysfunction (OR 1.7, 95%CI 1.0-2.7, p = 0.04) to have independent association with cognitive impairment.

CONCLUSION

This present study underscore that cognitive decline is considerably prevalent among individuals with systemic hypertension. In view of this, it is pivotal to incorporate cognitive assessment in routine evaluation of hypertensive patients.

Pharmacological treatment of hypertension in people without prior cerebrovascular disease for the prevention of cognitive impairment and dementia

BACKGROUND

This is an update of a Cochrane Review first published in 2006 (McGuinness 2006), and previously updated in 2009 (McGuinness 2009). Hypertension is a risk factor for dementia. Observational studies suggest antihypertensive treatment is associated with lower incidences of cognitive impairment and dementia. There is already clear evidence to support the treatment of hypertension after stroke.

OBJECTIVES

To assess whether pharmacological treatment of hypertension can prevent cognitive impairment or dementia in people who have no history of cerebrovascular disease.

SEARCH METHODS

We searched the Specialised Register of the Cochrane Dementia and Cognitive Improvement Group, CENTRAL, MEDLINE, Embase, three other databases, as well as many trials registries and grey literature sources, most recently on 7 July 2020.

SELECTION CRITERIA

We included randomised controlled trials (RCTs) in which pharmacological interventions to treat hypertension were given for at least 12 months. We excluded trials of pharmacological interventions to lower blood pressure in non-hypertensive participants. We also excluded trials conducted solely in people with stroke.

DATA COLLECTION AND ANALYSIS

Two authors independently assessed trial quality and extracted data. We contacted study authors for additional information. We collected information regarding incidence of dementia, cognitive decline, change in blood pressure, adverse effects and quality of life. We assessed the certainty of evidence using GRADE.

MAIN RESULTS

We included 12 studies, totaling 30,412 participants, in this review. Eight studies compared active treatment with placebo. Of the four non-placebo-controlled studies, two compared intensive versus standard blood pressure reduction. The two final included studies compared different classes of antihypertensive drug. Study durations varied from one to five years. The combined result of four placebo-controlled trials that reported incident dementia indicated no evidence of a difference in the risk of dementia between the antihypertensive treatment group and the placebo group (236/7767 versus 259/7660, odds ratio (OR) 0.89, 95% confidence interval (CI) 0.72 to 1.09; very low certainty evidence, downgraded due to study limitations and indirectness). The combined results from five placebo-controlled trials that reported change in Mini-Mental State Examination (MMSE) may indicate a modest benefit from antihypertensive treatment (mean difference (MD) 0.20, 95% CI 0.10 to 0.29; very low certainty evidence, downgraded due to study limitations, indirectness and imprecision). The certainty of evidence for both cognitive outcomes was downgraded on the basis of study limitations and indirectness. Study durations were too short, overall, to expect a significant difference in dementia rates between groups. Dementia and cognitive decline were secondary outcomes for most studies. Additional sources of bias include: the use of antihypertensive medication by the placebo group in the placebo-controlled trials; failure to reach recruitment targets; and early termination of studies on safety grounds. Meta-analysis of the placebo-controlled trials reporting results found a mean change in systolic blood pressure of -9.25 mmHg (95% CI -9.73, -8.78) between treatment (n = 8973) and placebo (n = 8820) groups, and a mean change in diastolic blood pressure of -2.47 mmHg (95% CI -2.70, -2.24) between treatment (n = 7700) and placebo (n = 7509) groups (both low certainty evidence downgraded on the basis of study limitations and inconsistency). Three trials - SHEP 1991, LOMIR MCT IL 1996 and MRC 1996 - reported more withdrawals due to adverse events in active treatment groups than placebo groups. Participants on active treatment in Syst Eur 1998 were less likely to discontinue treatment due to side effects, and participants on active treatment in HYVET 2008 reported fewer 'serious adverse events' than in the placebo group. There was no evidence of a difference in withdrawals rates between groups in SCOPE 2003, and results were unclear for Perez Stable 2000 and Zhang 2018. Heterogeneity precluded meta-analysis. Five of the placebo-controlled trials provided quality of life (QOL) data. Heterogeneity again precluded meta-analysis. SHEP 1991, Syst Eur 1998 and HYVET 2008 reported no evidence of a difference in QOL measures between active treatment and placebo groups over time. The SCOPE 2003 sub-study (Degl'Innocenti 2004) showed a smaller drop in QOL measures in the active treatment compared to the placebo group. LOMIR MCT IL 1996 reported an improvement in a QOL measure at twelve months in one active treatment group and deterioration in another.

AUTHORS' CONCLUSIONS

High certainty randomised controlled trial evidence regarding the effect of hypertension treatment on dementia and cognitive decline does not yet exist. The studies included in this review provide low certainty evidence (downgraded primarily due to study limitations and indirectness) that pharmacological treatment of hypertension, in people without prior cerebrovascular disease, leads to less cognitive decline compared to controls. This difference is below the level considered clinically significant. The studies included in this review also provide very low certainty evidence that pharmacological treatment of hypertension, in people without prior cerebrovascular disease, prevents dementia.

Calcium channel blockers, survival and ischaemic stroke in patients with dementia: a Swedish registry study

BACKGROUND

The effect of calcium channel blockers (CCB) on mortality and ischaemic stroke risk in dementia patients is understudied.

OBJECTIVES

To calculate the risk of death and ischaemic stroke in dementia patients treated with CCBs, considering individual agents and dose response.

METHODS

Longitudinal cohort study with 18 906 hypertensive dementia patients from the Swedish Dementia Registry (SveDem), 2008-2014. Other Swedish national registries contributed information on comorbidities, dispensed medication and outcomes. Individual CCB agents and cumulative defined daily doses (cDDD) were considered.

RESULTS

In patients with hypertension and dementia, nifedipine was associated with increased mortality risk (aHR 1.32; CI 1.01-1.73; P < 0.05) compared to non-CCB users. Patients diagnosed with Alzheimer's dementia (AD) or dementia with Lewy bodies/Parkinson's disease dementia (DLB-PDD) taking amlodipine had lower mortality risk (aHR, 0.89; CI, 0.80-0.98; P < 0.05 and aHR 0.58; CI, 0.38-0.86; P < 0.01, respectively), than those taking other CCBs. Amlodipine was associated with lower stroke risk in patients with Alzheimer's dementia compared to other CCBs (aHR 0.63; CI, 0.44-0.89; P < 0.05). Sensitivity analyses with propensity score-matched cohorts repeated the results for nifedipine (aHR 1.35; 95% CI, 1.02-1.78; P < 0.05) and amlodipine in AD (aHR, 0.87; CI, 0.78-0.97; P < 0.05) and DLB-PDD (aHR, 0.56, 95%CI, 0.37-0.85; P < 0.05).

CONCLUSION

Amlodipine was associated with reduced mortality risk in dementia patients diagnosed with AD and DLB-PDD. AD patients using amlodipine had a lower risk of ischaemic stroke compared to other CCB users.

The Utility of Cerebrovascular Reactivity MRI in Brain Rehabilitation: A Mechanistic Perspective

Cerebrovascular control and its integration with other physiological systems play a key role in the effective maintenance of homeostasis in brain functioning. Maintenance, restoration, and promotion of such a balance are one of the paramount goals of brain rehabilitation and intervention programs. Cerebrovascular reactivity (CVR), an index of cerebrovascular reserve, plays an important role in chemo-regulation of cerebral blood flow. Improved vascular reactivity and cerebral blood flow are important factors in brain rehabilitation to facilitate desired cognitive and functional outcomes. It is widely accepted that CVR is impaired in aging, hypertension, and cerebrovascular diseases and possibly in neurodegenerative syndromes. However, a multitude of physiological factors influence CVR, and thus a comprehensive understanding of underlying mechanisms are needed. We are currently underinformed on which rehabilitation method will improve CVR, and how this information can inform on a patient's prognosis and diagnosis. Implementation of targeted rehabilitation regimes would be the first step to elucidate whether such regimes can modulate CVR and in the process may assist in improving our understanding for the underlying vascular pathophysiology. As such, the high spatial resolution along with whole brain coverage offered by MRI has opened the door to exciting recent developments in CVR MRI. Yet, several challenges currently preclude its potential as an effective diagnostic and prognostic tool in treatment planning and guidance. Understanding these knowledge gaps will ultimately facilitate a deeper understanding for cerebrovascular physiology and its role in brain function and rehabilitation. Based on the lessons learned from our group's past and ongoing neurorehabilitation studies, we present a systematic review of physiological mechanisms that lead to impaired CVR in aging and disease, and how CVR imaging and its further development in the context of brain rehabilitation can add value to the clinical settings.

The Impact of Disease Comorbidities in Alzheimer's Disease

A wide range of comorbid diseases is associated with Alzheimer's disease (AD), the most common neurodegenerative disease worldwide. Evidence from clinical and molecular studies suggest that chronic diseases, including diabetes, cardiovascular disease, depression, and inflammatory bowel disease, may be associated with an increased risk of AD in different populations. Disruption in several shared biological pathways has been proposed as the underlying mechanism for the association between AD and these comorbidities. Notably, inflammation is a common dysregulated pathway shared by most of the comorbidities associated with AD. Some drugs commonly prescribed to patients with diabetes and cardiovascular disease have shown promising results in AD patients. Systems-based biology studies have identified common genetic factors and dysregulated pathways that may explain the relationship of comorbid disorders in AD. Nonetheless, the precise mechanisms for the occurrence of disease comorbidities in AD are not entirely understood. Here, we discuss the impact of the most common comorbidities in the clinical management of AD patients.

Antihypertensive Medication Classes and the Risk of Dementia: A Systematic Review and Network Meta-Analysis

OBJECTIVES

To systematically review and synthesize the evidence on differential associations between antihypertensive medication (AHM) classes and the risk of incident dementia.

DESIGN

Systematic review and random effects frequentist network meta-analysis. Embase, MEDLINE, and the Cochrane library were searched from origin to December 2019.

SETTING AND PARTICIPANTS

Randomized controlled trials (RCTs) and prospective cohort studies that compared associations of different AHM classes with incident all-cause dementia and/or Alzheimer's disease over at least 1 year of follow-up.

MEASURES

All cause dementia and/or Alzheimer's disease.

RESULTS

Fifteen observational studies and 7 RCTs were included. Data on AHM classes were available for 649,790 participants and dementia occurred in 19,600 (3.02%). Network meta-analysis showed that in observational studies, treatment with either calcium channel blockers (CCBs) or angiotensin II receptor blockers (ARBs) was associated with lower dementia risks than treatment with other antihypertensives: CCBs vs angiotensin converting enzyme inhibitors (ACE inhibitors) (HR=0.84, 95% CI 0.74-0.95), beta blockers (HR=0.83, 95% CI 0.73-0.95) and diuretics (HR=0.89, 95% CI 0.78-1.01) and ARBs vs ACE inhibitors (HR=0.88, 95% CI 0.81-0.97), beta blockers (HR=0.87, 95% CI 0.77-0.99), and diuretics (HR=0.93, 95% CI 0.83-1.05). There were insufficient RCTs to create a robust network based on randomized data alone.

CONCLUSIONS AND IMPLICATIONS

Recommending CCBs or ARBs as preferred first-line antihypertensive treatment may significantly reduce the risk of dementia. If corroborated in a randomized setting, these findings reflect a low-cost and scalable opportunity to reduce dementia incidence worldwide.

Glia-Driven Neuroinflammation and Systemic Inflammation in Alzheimer's Disease

The neuroinflammatory hypothesis of Alzheimer's disease (AD) was proposed more than 30 years ago. The involvement of the two main types of glial cells microglia and astrocytes, in neuroinflammation, was suggested early on. In this review, we highlight that the exact contributions of reactive glia to AD pathogenesis remain difficult to define, likely due to the heterogeneity of glia populations and alterations in their activation states through the stages of AD progression. In the case of microglia, it is becoming apparent that both beneficially and adversely activated cell populations can be identified at various stages of AD, which could be selectively targeted to either limit their damaging actions or enhance beneficial functions. In the case of astrocytes, less information is available about potential subpopulations of reactive cells; it also remains elusive whether astrocytes contribute to the neuropathology of AD by mainly gaining neurotoxic functions or losing their ability to support neurons due to astrocyte damage. We identify L-type calcium channel blocker, nimodipine, as a candidate drug for AD, which potentially targets both astrocytes and microglia. It has already shown consistent beneficial effects in basic experimental and clinical studies. We also highlight the recent evidence linking peripheral inflammation and neuroinflammation. Several chronic systemic inflammatory diseases, such as obesity, type 2 diabetes mellitus, and periodontitis, can cause immune priming or adverse activation of glia, thus exacerbating neuroinflammation and increasing risk or facilitating the progression of AD. Therefore, reducing peripheral inflammation is a potentially effective strategy for lowering AD prevalence.

Calcium-Handling Defects and Neurodegenerative Disease

Calcium signaling is critical to neuronal function and regulates highly diverse processes such as gene transcription, energy production, protein handling, and synaptic structure and function. Because there are many common underlying calcium-mediated pathological features observed across several neurological conditions, it has been proposed that neurodegenerative diseases have an upstream underlying calcium basis in their pathogenesis. With certain diseases such as Alzheimer's, Parkinson's, and Huntington's, specific sources of calcium dysregulation originating from distinct neuronal compartments or channels have been shown to have defined roles in initiating or sustaining disease mechanisms. Herein, we will review the major hallmarks of these diseases, and how they relate to calcium dysregulation. We will then discuss neuronal calcium handling throughout the neuron, with special emphasis on channels involved in neurodegeneration.

Blood Pressure and Risks of Cognitive Impairment and Dementia: A Systematic Review and Meta-Analysis of 209 Prospective Studies

Controversies persist regarding the association between blood pressure (BP) and the risks of cognitive impairment and dementia due to inconsistent definitions of BP exposure and varying population characteristics. Here, we searched PubMed and performed a meta-analysis of the influence of BP exposure on the risks of cognitive disorders in prospective studies. Dose-response analyses were performed to illustrate the existence of linear/nonlinear relationships. The credibility of each meta-analysis was evaluated according to the risk of bias, inconsistency, and imprecision. Of the 31 628 citations, 209 were included in our systematic review, among which 136 were eligible for the meta-analysis. Overall, stronger associations were found in midlife than late-life. Moderate-quality evidence indicated that midlife hypertension was related to a 1.19- to 1.55-fold excess risk of cognitive disorders. Dose-response analyses of 5 studies indicated that midlife systolic BP >130 mm Hg was associated with an increased risk of cognitive disorders. With regard to BP exposure in late-life, high systolic BP, low diastolic BP, excessive BP variability, and orthostatic hypotension were all associated with an increased dementia risk. Encouragingly, the use of antihypertensive medications exhibited a 21% reduction in dementia risk. The U-shaped dose-response curve indicated that the protective window of diastolic BP level was between 90 and 100 mm Hg for low risk of Alzheimer disease. The relationships between BP variables and cognitive disorders are age- and BP type-dependent. Antihypertensive medications were associated with a reduced risk of dementia. However, the optimal dose, duration, and type for preventing cognitive disorders warrant further investigation.

Verapamil and Alzheimer's Disease: Past, Present, and Future

Verapamil is a phenylalkylamine class calcium channel blocker that for half a century has been used for the treatment of cardiovascular diseases. Nowadays, verapamil is also considered as a drug option for the treatment of several neurological and psychiatric disorders, such as cluster headache, bipolar disorders, epilepsy, and neurodegenerative diseases. Here, we review insights into the potential preventive and therapeutic role of verapamil on Alzheimer’s disease (AD) based on limited experimental and clinical data. Pharmacological studies have shown that verapamil has a wide therapeutic spectrum, including antihypertensive, anti-inflammatory, and antioxidative effects, regulation of the blood-brain barrier function, due to its effect on P-glycoprotein, as well as adjustment of cellular calcium homeostasis, which may result in the delay of AD onset or ameliorate the symptoms of patients. However, the majority of the AD individuals are on polypharmacotherapy, and the interactions between verapamil and other drugs need to be considered. Therefore, for an appropriate and successful AD treatment, a personalized approach is more than necessary. A well-known narrow pharmacological window of verapamil efficacy may hinder this approach. It is therefore important to note that the verapamil efficacy may be conditioned by different factors. The onset, grade, and brain distribution of AD pathological hallmarks, the time-sequential appearances of AD-related cognitive and behavioral dysfunction, the chronobiologic and gender impact on calcium homeostasis and AD pathogenesis may somehow be influencing that success. In the future, such insights will be crucial for testing the validity of verapamil treatment on animal models of AD and clinical approaches.

Targeting microglia L-type voltage-dependent calcium channels for the treatment of central nervous system disorders

Calcium (Ca²⁺ ) is a ubiquitous mediator of a multitude of cellular functions in the central nervous system (CNS). Intracellular Ca²⁺ is tightly regulated by cells, including entry via plasma membrane Ca²⁺ permeable channels. Of specific interest for this review are L-type voltage-dependent Ca²⁺ channels (L-VDCCs), due to their pleiotropic role in several CNS disorders. Currently, there are numerous approved drugs that target L-VDCCs, including dihydropyridines. These drugs are safe and effective for the treatment of humans with cardiovascular disease and may also confer neuroprotection. Here, we review the potential of L-VDCCs as a target for the treatment of CNS disorders with a focus on microglia L-VDCCs. Microglia, the resident immune cells of the brain, have attracted recent attention for their emerging inflammatory role in several CNS diseases. Intracellular Ca²⁺ regulates microglia transition from a resting quiescent state to an "activated" immune-effector state and is thus a valuable target for manipulation of microglia phenotype. We will review the literature on L-VDCC expression and function in the CNS and on microglia in vitro and in vivo and explore the therapeutic landscape of L-VDCC-targeting agents at present and future challenges in the context of Alzheimer's disease, Parkinson's disease, Huntington's disease, neuropsychiatric diseases, and other CNS disorders.

Does Treating Vascular Risk Factors Prevent Dementia and Alzheimer's Disease? A Systematic Review and Meta-Analysis

BACKGROUND

Epidemiological evidence has associated Alzheimer's disease (AD) with vascular risk factors (VRFs), but whether treatment of VRFs reduces the incidence of dementia and AD is uncertain.

OBJECTIVE

To conduct a systematic review and meta-analysis to summarize available data on the impact of treatment of VRFs on dementia and AD incidence.

METHODS

Pertinent studies published until 1 January 2018 were identified from PubMed. Both randomized controlled trials (RCT) and prospective studies that investigated the impact of treatment of VRFs on dementia or AD incidence were included.

RESULTS

Eight RCTs and 52 prospective studies were identified. Antihypertensive treatment was associated with a non-significant reduced risk of dementia in RCTs (n = 5; relative risk [RR], 0.84; 95% confidence interval [CI], 0.69-1.02) and prospective studies (n = 3; RR, 0.77; 95% CI, 0.58-1.01) and with reduced AD risk in prospective studies (n = 5; RR = 0.78; 95% CI, 0.66-0.91). In prospective studies, treatment of hyperlipidemia with statins, but not nonstatin lipid-lowering agents, was associated with reduced risk of dementia (n = 17; RR, 0.77; 95% CI, 0.63-0.95) and AD (n = 13; RR, 0.86; 95% CI, 0.80-0.92). The single RCT on statins and dementia incidence showed no association. Data from one RCT and six prospective studies did not support a beneficial impact of antidiabetic drugs or insulin therapy on dementia risk.

CONCLUSION

Current evidence indicates that antihypertensives and statins might reduce the incidence of dementia and AD. Further trials to determine the effect of VRF on AD are needed.

Nitrendipine and Dementia: Forgotten Positive Facts?

Nowadays, there are about 50 million people suffering from dementia worldwide. In 2030, it is expected that there will be 82 million people living with dementia and in 2050, their number should reach 152 million. This increase in the number of people with dementia results in significant social and economic problems. Therefore, researchers attempt to reduce risk factors causing the development of dementia such as high blood pressure. Epidemiological studies have shown that hypertension increases the risk of dementia at an older age. It can, therefore, be assumed that hypertension therapy will reduce the risk of dementia. However, previous clinical studies have shown that the efficacy of different antihypertensive drugs differs in this respect. The drug group that appears to be the most effective in these analyses is calcium channel blockers (CCBs). The most significant preventive efficacy in terms of protection against dementia has been demonstrated with nitrendipine. Its use is, therefore, particularly advantageous in elderly patients with systolic hypertension who are at high risk of dementia. The purpose of this study is to restore the discussion on the prevention of vascular dementia and Alzheimer’s dementia with nitrendipine in indicated hypertonic patients. The authors performed a literature search of available sources describing the issue of dementia, hypertension and its treatment with nitrendipine. In addition, they made a comparison and evaluation of relevant findings. The results of the detected research studies indicate that nitrendipine is able to reduce the incidence of dementia [Alzheimer’s disease (AD), vascular and mixed] by 55%. The treatment of 1,000 patients with nitrendipine for 5 years may prevent 20 cases of dementia. However, what has not yet been explained is the temporal link between hypertension and dementia due to the long-time intervals between hypertension and the development of dementia.

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.

Effect of SSRI and calcium channel blockers on depression symptoms and cognitive function in elderly persons treated for hypertension: three city cohort study

ABSTRACTBackground:Emerging genetic, ex-vivo, and clinical trial evidence indicates that calcium channel blockers (CCB) can improve mood and cognitive function. The objective of this study was to examine the effect of selective serotonin reuptake inhibitor (SSRI) therapy augmented with CCB on depression and cognitive decline in an elderly population with hypertension.

METHODS

Prospective study of 296 persons treated with SSRI and antihypertensive drugs. Baseline and two year clinic assessments were used to categorize participants as users of SSRI + CCB (n = 53) or users of SSRI + other antihypertensives (n = 243). Clinic visits were performed up to four times in a ten-year period to assess depression and cognitive function.

RESULTS

The sample mean age was 75.2 ± 5.47 years and 78% of participants were female. At two year follow-up there was a significant group by time interaction showing lower Center for Epidemiological Studies-Depression (CESD) scores in the SSRI + CCB group, F(1,291) = 4.13, p = 0.043, η2p = 0.014. Over ten-years follow-up, SSRI + CCB use was associated with improved general cognitive function (Mini-Mental State Examination: β = 0.97; 95% CI 0.14 to 1.81, p = 0.023) and immediate visual memory (Boston Visual Retention Test: β = 0.69; 95% CI 0.06 to 1.32, p = 0.033).

CONCLUSION

The findings provide general population evidence that SSRI augmentation with CCB may improve depression and cognitive function.

Nilvadipine in mild to moderate Alzheimer disease: A randomised controlled trial

BACKGROUND

This study reports the findings of the first large-scale Phase III investigator-driven clinical trial to slow the rate of cognitive decline in Alzheimer disease with a dihydropyridine (DHP) calcium channel blocker, nilvadipine. Nilvadipine, licensed to treat hypertension, reduces amyloid production, increases regional cerebral blood flow, and has demonstrated anti-inflammatory and anti-tau activity in preclinical studies, properties that could have disease-modifying effects for Alzheimer disease. We aimed to determine if nilvadipine was effective in slowing cognitive decline in subjects with mild to moderate Alzheimer disease.

METHODS AND FINDINGS

NILVAD was an 18-month, randomised, placebo-controlled, double-blind trial that randomised participants between 15 May 2013 and 13 April 2015. The study was conducted at 23 academic centres in nine European countries. Of 577 participants screened, 511 were eligible and were randomised (258 to placebo, 253 to nilvadipine). Participants took a trial treatment capsule once a day after breakfast for 78 weeks. Participants were aged >50 years, meeting National Institute of Neurological and Communicative Disorders and Stroke/Alzheimer's disease Criteria (NINCDS-ADRDA) for diagnosis of probable Alzheimer disease, with a Standardised Mini-Mental State Examination (SMMSE) score of ≥12 and <27. Participants were randomly assigned to 8 mg sustained-release nilvadipine or matched placebo. The a priori defined primary outcome was progression on the Alzheimer's Disease Assessment Scale Cognitive Subscale-12 (ADAS-Cog 12) in the modified intention-to-treat (mITT) population (n = 498), with the Clinical Dementia Rating Scale sum of boxes (CDR-sb) as a gated co-primary outcome, eligible to be promoted to primary end point conditional on a significant effect on the ADAS-Cog 12. The analysis set had a mean age of 73 years and was 62% female. Baseline demographic and Alzheimer disease-specific characteristics were similar between treatment groups, with reported mean of 1.7 years since diagnosis and mean SMMSE of 20.4. The prespecified primary analyses failed to show any treatment benefit for nilvadipine on the co-primary outcome (p = 0.465). Decline from baseline in ADAS-Cog 12 on placebo was 0.79 (95% CI, -0.07-1.64) at 13 weeks, 6.41 (5.33-7.49) at 52 weeks, and 9.63 (8.33-10.93) at 78 weeks and on nilvadipine was 0.88 (0.02-1.74) at 13 weeks, 5.75 (4.66-6.85) at 52 weeks, and 9.41 (8.09-10.73) at 78 weeks. Exploratory analyses of the planned secondary outcomes showed no substantial effects, including on the CDR-sb or the Disability Assessment for Dementia. Nilvadipine appeared to be safe and well tolerated. Mortality was similar between groups (3 on nilvadipine, 4 on placebo); higher counts of adverse events (AEs) on nilvadipine (1,129 versus 1,030), and serious adverse events (SAEs; 146 versus 101), were observed. There were 14 withdrawals because of AEs. Major limitations of this study were that subjects had established dementia and the likelihood that non-Alzheimer subjects were included because of the lack of biomarker confirmation of the presence of brain amyloid.

CONCLUSIONS

The results do not suggest benefit of nilvadipine as a treatment in a population spanning mild to moderate Alzheimer disease.

TRIAL REGISTRATION

Clinicaltrials.gov NCT02017340, EudraCT number 2012-002764-27.

Antihypertensive Medication Regimen Intensity and Incident Dementia in an Older Population

OBJECTIVE

To investigate the association between antihypertensive medication regimen intensity and risk of incident dementia in an older population.

DESIGN

Prospective, longitudinal cohort study.

PARTICIPANTS/SETTING

A total of 1208 participants aged ≥78 years, free of dementia, and residing in central Stockholm at baseline (2001-2004).

MEASUREMENTS

Participants were examined at 3- and 6-year follow-up to detect incident dementia. Data were collected through face-to-face interviews, clinical examinations, and laboratory tests. Data on antihypertensive use were obtained by a physician through patient self-report, visual inspection, or medical records. Cox proportional hazards models were used to compute hazard ratios (HRs) and 95% confidence intervals (CIs) for the association between time-varying antihypertensive regimen intensity and incident dementia after adjusting for potential confounders.

RESULTS

During the follow-up period, 125 participants were diagnosed with dementia. Participants who developed dementia were more likely to have vascular disease at baseline (66.4% vs 55.3%, P = .02). In fully adjusted analyses, the number of antihypertensive classes (HR 0.68, 95% CI 0.55-0.84) and total prescribed daily dose (HR 0.70, 95% CI 0.57-0.86) were significantly associated with reduced dementia risk. After considering all-cause mortality as a competing risk, the number (HR 0.75, 95% CI 0.62-0.91) and doses (HR 0.71, 95% CI 0.59-0.86) of antihypertensive classes, and the independent use of diuretics (HR 0.66, 95% CI 0.44-0.99), were significantly associated with lower dementia risk.

CONCLUSIONS

Greater intensity of antihypertensive drug use among older people may be associated with reduced incidence of dementia.

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.

Amlodipine, an L-type calcium channel blocker, protects against chlorpromazine-induced neurobehavioural deficits in mice

This study investigated the modulatory and chemopreventive benefit of amlodipine (AML), a dihydropyridine calcium channel antagonist, against neurobehavioural abnormalities (NAs) associated with chlorpromazine (CPZ) toxicity in mice. Adult mice were divided into five groups of six animals/group. Group 1 (control) was administered saline (10 mL/kg i.p.). Group 2 received CPZ (2 mg/kg i.p.). Groups 3 and 4 received bromocriptine (BMC, 2.5 mg/kg s.c.) and AML (1 mg/kg s.c.), respectively, while group 5 received their combination. Groups 3-5 later received CPZ 30 min after initial treatments. Animals were subjected to neurobehavioural tests and euthanized 18 h later. CPZ-induced NAs were characterized by significant increase (P < 0.001) in cataleptic behaviour and lowered (P < 0.05) spontaneous activity reaction time in mice. There were also significant (P < 0.001) increases in malondialdehyde levels and decreased locomotion plus learning and memory parameters (P < 0.05-0.001). AML pretreatment alone did not alleviate CPZ-induced motor deficits in the mice. While pretreatment with BMC alone attenuated CPZ-associated catalepsy, its combination with AML further protected mice against NAs. Furthermore, BMC pretreatment did not affect CPZ-induced increase in malondialdehyde level, but AML or BMC+AML significantly (P < 0.05) decreased malondialdehyde in the CPZ-treated rats. Reduced glutathione levels and activities of superoxide dismutase and catalase remained elevated in all treatment groups. In conclusion, data from this study suggest possible chemopreventive benefit of AML alone or in combination with BMC against CPZ-associated neurobehavioural deficits. The ameliorative effect of AML may be related to its antioxidant and/or calcium channel blocking property.

Covalently anchored sulfamic acid on cellulose as heterogeneous solid acid catalyst for the synthesis of structurally symmetrical and unsymmetrical 1,4-dihydropyridine derivatives

A novel heterogeneous solid acid catalyst has been prepared by covalent grafting of chlorosulphonic acid on amino-functionalized cellulose (Cell–Pr-NHSO₃H).

Antihypertensive withdrawal for the prevention of cognitive decline

BACKGROUND

Clinical trials and observational data have variously shown a protective, harmful or neutral effect of antihypertensives on cognitive function. In theory, withdrawal of antihypertensives could improve cerebral perfusion and reduce or delay cognitive decline. However, it is also plausible that withdrawal of antihypertensives may have a detrimental effect on cognition through increased incidence of stroke or other vascular events.

OBJECTIVES

To assess the effects of complete withdrawal of at least one antihypertensive medication on incidence of dementia, cognitive function, blood pressure and other safety outcomes in cognitively intact and cognitive impaired adults.

SEARCH METHODS

We searched ALOIS, the specialised register of the Cochrane Dementia and Cognitive Improvement Group, with additional searches conducted in MEDLINE, Embase, PsycINFO, CINAHL, LILACS, Web of Science Core Collection, ClinicalTrials.gov and the World Health Organization Portal/ICTRP on 12 December 2015. There were no language or date restrictions applied to the electronic searches, and no methodological filters were used to restrict the search.

SELECTION CRITERIA

We included randomised controlled trials (RCTs) and controlled clinical trials (CCTs) provided they compared withdrawal of antihypertensive medications with continuation of the medications and included an outcome measure assessing cognitive function or a clinical diagnosis of dementia. We included studies with healthy participants, but we also included studies with participants with all grades of severity of existing dementia or cognitive impairment.

DATA COLLECTION AND ANALYSIS

Two review authors examined titles and abstracts of citations identified by the search for eligibility, retrieving full texts where needed to identify studies for inclusion, with any disagreement resolved by involvement of a third author. Data were extracted independently on primary and secondary outcomes. We used standard methodological procedures expected by Cochrane.The primary outcome measures of interest were changes in global and specific cognitive function and incidence of dementia; secondary outcomes included change in systolic and diastolic blood pressure, mortality, adverse events (including cardiovascular events, hospitalisation and falls) and adherence to withdrawal. The quality of the evidence was evaluated using the GRADE approach.

MAIN RESULTS

We included two RCTs investigating withdrawal of antihypertensives in 2490 participants. There was substantial clinical heterogeneity between the included studies, therefore we did not combine data for our primary outcome. Overall, the quality of included studies was high and the risk of bias was low. Neither study investigated incident dementia.One study assessed withholding previously prescribed antihypertensive drugs for seven days following acute stroke. Cognition was assessed using telephone Mini-Mental State Examination (t-MMSE) and Telephone Interview for Cognitive Status (TICS-M) at 90 days as a secondary outcome. The t-MMSE score was a mean of 1.0 point higher in participants who withdrew antihypertensive medications compared to participants who continued them (95% confidence interval (CI) 0.35 to 1.65; 1784 participants) and the TICS-M was a mean of 2.10 points higher (95% CI 0.69 to 3.51; 1784 participants). However, in both cases the evidence was of very low quality downgraded due to risk of bias, indirectness and evidence from a single study. The other study was community based and included participants with mild cognitive impairment. Drug withdrawal was for 16 weeks. Cognitive performance was assessed using a composite of at least five out of six cognitive tests. There was no evidence of a difference comparing participants who withdrew antihypertensive medications and participants who continued (mean difference 0.02 points, 95% CI -0.19 to 0.21; 351 participants). This evidence was of low quality and was downgraded due to risk of bias and evidence from single study.In one study, the systolic blood pressure after seven days of withdrawal was 9.5 mmHg higher in the intervention compared to the control group (95% CI 7.43 to 11.57; 2095 participants) and diastolic blood pressure was 5.1 mmHg higher (95% CI 3.86 to 6.34; 2095 participants). This evidence was low quality, downgraded due to indirectness, because the data must be interpreted in the context of the wider study looking at glyceryl trinitrate administration or not, and evidence from a single study. In the other study, systolic blood pressure increased by 7.4 mmHg in the withdrawal group compared to the control group (95% CI 7.08 to 7.72; 356 participants) and diastolic blood pressure increased by 2.6 mmHg (95% CI 2.42 to 2.78; 356 participants). This was moderate quality evidence, downgraded as evidence was from a single study. We combined data for mortality and cardiovascular events. There was no clear evidence that antihypertensive medication withdrawal affected adverse events, although there was a possible trend to increased cardiovascular events in the large post-stroke study (pooled mortality risk ratio 0.88, 95% CI 0.72 to 1.08; 2485 participants; and cardiovascular events risk ratio 1.29, 95% CI 0.96 to 1.72). Certain prespecified outcomes of interest (falls, hospitalisation) were not reported.

AUTHORS' CONCLUSIONS

The effects of withdrawing antihypertensive medications on cognition or prevention of dementia are uncertain. There was a signal of a positive effect in one study looking at withdrawal after acute stroke but these results are unlikely to be generalisable to non-stroke settings and were not a primary outcome of the study. Withdrawing antihypertensive drugs was associated with increased blood pressure. It is unlikely to increase mortality at three to four months' follow-up, although there was a signal from one large study looking at withdrawal after stroke that withdrawal was associated an increase in cardiovascular events.

A 10-year follow-up study of the association between calcium channel blocker use and the risk of dementia in elderly hypertensive patients

Calcium channel blockers (CCBs) are widely used for reducing blood pressure of hypertensive patients. Recent reports document the beneficial effects of CCB for preventing dementia; however, the results are controversial. We aim to evaluate the risk of developing dementia among elderly hypertensive patients treated with CCB.We designed a retrospective population-based cohort study using the records of the National Health Insurance Research Database of Taiwan dated from 2000 to 2010. The study cohort comprised 82,107 hypertensive patients of more than 60 years of age, and 4004 propensity score (PS)-matched pairs were selected according to age, sex, year of hypertension diagnosis, and baseline comorbidities. We employed a robust Cox proportional hazard model to estimate the hazard ratio (HR) of developing dementia in the PS-matched cohort.The annual incidence of dementia in the CCB-exposure group was significantly lower than that in the comparator group (3.9 vs 6.9 per 1000 person-years, P < 0.01) during the follow-up period (4.4 ± 2.5 years). Based on the PS-matched cohort, the adjusted HR of dementia in the CCB-exposure group was significantly lower than that in comparator group (HR = 0.53, 95% confidence interval: 0.39-0.72, P < 0.01). Sensitivity and subgroup analyses also confirmed similar findings.Our results provided evidence for an association between CCB use and a lower risk of developing dementia among the elderly hypertensive patients. Further studies are required to explore the causal relationship between CCB use and dementia.

Amlodipine treatment of hypertension associates with a decreased dementia risk

Hypertension has been shown to be a risk factor for development of dementia. However, medical treatment of hypertension failed to reduce consistently the risk of dementia. Experimental study pointed to the possibility of difference between different calcium channel blockers (CCB) in their neuro-protective effect. The aim of our study was to evaluate the risk of dementia during treatment of hypertension with different CCBs. This is a retrospective cohort study based on electronic database of a large public health care organization. Study period was 11 years and it included patients aged 40-75 years old, having diagnosis of hypertension without diagnosis of dementia at the starting point, treated with either single specific CCB (study group) or with other than CCBs antihypertensive medications (control group) for at least 30 months during the study period. A total of 15,664 patients that satisfied these criteria were identified: 3,884 were treated with amlodipine, 2,062 were treated with nifedipine, 609 were treated with lercanidipine, and 9,109 never received CCBs. Dementia developed in 765 (4.9%) patients. Adjusted hazard ratio (HR) for dementia in patients treated with amlodipine, nifedipine, and lercanidipine was 0.60 (p < 0.001), 0.89 (NS), and 0.90 (NS). Decreased adjusted HR of dementia with amlodipine was demonstrated in the patients aged 60 or more (HR 0.61 [0.49-0.77], p < 0.001), but not in the patients aged less than 60 years old. This study shows that amlodipine therapy may be associated with a decreased dementia risk in hypertensive individuals older than 60 years, compared to those treated without CCBs.

Antihypertensive drug use and risk of cognitive decline in the very old: an observational study - the Newcastle 85+ Study

OBJECTIVES

Older adults are a fast growing group in society and are at high risk of hypertension, cognitive decline and dementia. Antihypertensive drugs, particularly calcium channel blockers (CCB), have been associated with a decreased risk of cognitive decline and dementia. We used observational data to examine the association between antihypertensive drug class and change in cognitive function.

METHODS

The Newcastle 85+ Study is a population-based cohort study recruiting individuals aged 85 (born in 1921) via general/family practices in Newcastle/North Tyneside, United Kingdom. Data, including blood pressure, antihypertensive drug use and cognitive function [assessed using the Standardized Mini-Mental State Exam (SMMSE)], were collected at baseline and 3-year follow-up.

RESULTS

The study population comprised 238 participants with a diagnosis of hypertension, prescribed antihypertensive drug treatment and with baseline and follow-up SMMSE assessment. There was an association between CCB use and less cognitive decline over 3 years (rate of decline was lower by 1.29 SMMSE points (95% confidence interval 0.16-2.42; P = 0.03) compared with those taking other antihypertensive classes after adjustment for age, sex, years of education, baseline SMMSE score, smoking, BMI, baseline blood pressure, and incident cerebrovascular event. This finding was even stronger in the cognitively intact (SMMSE >24), wherein rate of cognitive decline was lower by 1.33 SMMSE points (95% confidence interval 0.30-2.37; P = 0.01), but was not seen for other antihypertensive classes.

CONCLUSION

Findings provide support for an association between CCB use and a lower rate of cognitive decline in very old adults with hypertension.

A systematic review of calcium channel blocker use and cognitive decline/dementia in the elderly

OBJECTIVE

Treating hypertension in those aged at least 80 years is now recommended; however, the best antihypertensive to choose remains unexplored. Calcium channel blocker (CCB) use has been associated with a decreased risk of incident dementia in a younger hypertensive group but with an increased risk of cognitive decline in the very elderly. Either result could have a large impact on a vulnerable population. The aim of this review was to assess the evidence relating CCB use to later cognitive decline or dementia in the very elderly.

METHODS

A systematic review of the literature was carried out. The databases Medline, PubMed, Embase and Psychinfo were searched from 1980 to 22 August 2013. Abstracts were reviewed by two independent reviewers and papers meeting the inclusion criteria were extracted.

RESULTS

One thousand, nine hundred and sixty-eight records were reviewed and 10 articles reporting on nine studies retained and extracted. Data were primarily from cohort studies. Only one reported a randomized controlled trial comparing CCBs with placebo. Populations, comparator groups, follow-up times, outcomes and exposure varied and overall results were mixed. It was not possible to combine all studies, but those reporting Alzheimer's disease outcomes were combined to produce an overall risk ratio of 0.79 (95% confidence interval 0.53-1.17).

CONCLUSION

At present, there is no clear evidence to suggest that CCB use increases or decreases risk of cognitive decline or dementia in the very elderly. A robust clinical trial is now required to resolve this.

Introduction of a novel nanosized N-sulfonated Brönsted acidic catalyst for the promotion of the synthesis of polyhydroquinoline derivatives via Hantzsch condensation under solvent-free conditions

In this research NS-C₄(DABCO-SO₃H)₂)·4Cl as a new nano sized N-sulfonic acid was prepared and characterized using different types of methods including FT-IR, ¹H NMR, ¹³C NMR, mass, XRD, TGA, SEM and AFM analysis.

Dantrolene, a treatment for Alzheimer disease?

Alzheimer disease (AD) is a fatal progressive disease and the most common form of dementia without effective treatments. Previous studies support that the disruption of endoplasmic reticulum Ca through overactivation of ryanodine receptors plays an important role in the pathogenesis of AD. Normalization of intracellular Ca homeostasis could be an effective strategy for AD therapies. Dantrolene, an antagonist of ryanodine receptors and an FDA-approved drug for clinical treatment of malignant hyperthermia and muscle spasms, exhibits neuroprotective effects in multiple models of neurodegenerative disorders. Recent preclinical studies consistently support the therapeutic effects of dantrolene in various types of AD animal models and were summarized in the current review.

Potential for specific dihydropyridine calcium channel blockers to have a positive impact on cognitive function in humans: a systematic review

BACKGROUND

There is some evidence to suggest a possible association between calcium channel blocker (CCB) use and a lower decline in cognitive function compared with use of other hypertensive treatments. In particular, there is an emerging interest in the potential for specific CCBs, particularly the dihydropyridine CCBs nitrendipine, nicardipine, cilnidipine, lercandipine, nimodipine, azelnidipine and nilvadipine. The aim of this review was to assess the evidence relating to these specific CCBs and incident cognitive decline or dementia in humans.

METHODS

A systematic review of the literature was carried out. The databases MEDLINE, Embase and PsychINFO were searched from 1980 to 18 April 2014. All abstracts were reviewed by two independent reviewers.

RESULTS

From 753 unique records, 16 full text articles were examined and three retained. The three articles reported data from two studies. A 12-week double-blind randomized controlled trial of nitrendipine compared with cilazapril and a longer and larger double-blind placebo-controlled trial also of nitrendipine, namely the Systolic Hypertension in Europe trial (SYST-EUR). Nitrendipine was associated with a reduction in incident dementia in the SYST-EUR trial. There was no association seen for cognitive outcomes in the smaller trial.

CONCLUSION

At present there is limited evidence to suggest that nitrendipine may be associated with reduction in incident dementia. This association comes from a single trial and needs to be replicated. Furthermore, there is no high-quality evidence for any of the other potential candidate CCBs.

Anticholinesterase and antioxidant investigations of crude extracts, subsequent fractions, saponins and flavonoids of atriplex laciniata L.: potential effectiveness in Alzheimer's and other neurological disorders

Background

Atriplex laciniata L. was investigated for phenolic, flavonoid contents, antioxidant, anticholinesterase activities, in an attempt to explore its effectiveness in Alzheimer’s and other neurological disorders. Plant crude methanolic extract (Al.MeF), subsequent fractions; n-hexane (Al.HxF), chloroform (Al.CfF), ethyl acetate (Al.EaF), aqueous (Al.WtF), Saponins (Al.SPF) and Flavonoids (Al.FLVF) were investigated for DPPH, ABTS and H₂O₂ free radical scavenging activities. Further these extracts were subjected to acetylcholinesterase (AChE) & butyrylcholinesterase (BChE) inhibitory activities using Ellman’s assay. Phenolic and Flavonoid contents were determined and expressed in mg Gallic acid GAE/g and Rutin RTE/g of samples respectively.

Results

In DPPH free radicals scavenging assay, Al.FLVF, Al.SPF and Al.MeF showed highest activity causing 89.41 ± 0.55, 83.37 ± 0.34 and 83.37 ± 0.34% inhibition of free radicals respectively at 1 mg/mL concentration. IC₅₀ for these fractions were 33, 83 and 82 μg/mL respectively. Similarly, plant extracts showed high ABTS scavenging potential, i.e. Al.FLVF (90.34 ± 0.55), Al.CfF (83.42 ± 0.57), Al.MeF (81.49 ± 0.60) with IC₅₀ of 30, 190 and 70 μg/ml respectively. further, H₂O₂ percent scavenging was highly appraised in Al.FLVF (91.29 ± 0.53, IC₅₀ 75), Al.SPF (85.35 ± 0.61, IC₅₀ 70) and Al.EaF (83.48 ± 0.67, IC₅₀ 270 μg/mL). All fractions exhibited concentration dependent AChE inhibitory activity as; Al.FLVF, 88.31 ± 0.57 (IC₅₀ 70 μg/mL), Al.SPF, 84.36 ± 0.64 (IC₅₀ 90 μg/mL), Al.MeF, 78.65 ± 0.70 (IC₅₀ 280 μg/mL), Al.EaF, 77.45 ± 0.46 (IC₅₀ 270 μg/mL) and Al.WtF 72.44 ± 0.58 (IC₅₀ 263 μg/mL) at 1 mg/mL. Likewise the percent BChE inhibitory activity was most obvious in Al.FLVF 85.46 ± 0.62 (IC₅₀ 100 μg/mL), Al.CfF 83.49 ± 0.46 (IC₅₀ 160 μg/mL), Al.MeF 82.68 ± 0.60 (IC₅₀ 220 μg/mL) and Al.SPF 80.37 ± 0.54 (IC₅₀ 120 μg/mL).

Conclusions

These results stipulate that A. laciniata is enriched with phenolic and flavonoid contents that possess significant antioxidant and anticholinestrase effects. This provide pharmacological basis for the presence of compounds that may be effective in Alzheimer’s and other neurological disorders.

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.

Cognitive impairment and cardiovascular diseases in the elderly. A heart-brain continuum hypothesis

The aging population is increasing and, therefore, a higher prevalence of cardiac disease is emerging; including hypertension, coronary artery disease, atrial fibrillation and chronic heart failure. Large cohort studies have revealed a relationship among increased risk for cognitive impairment and dementia in cardiovascular diseases probably due to embolic stroke or chronic cerebral hypoperfusion. Thus, the aim of the present review is to overview the studies that investigate the presence and/or the development of cognitive impairments and dementia in patients with varied types of cardiovascular disease. Finally, a continuum among hypertension, coronary artery disease, atrial fibrillation and chronic heart failure with to the development of cognitive impairment and progression to dementia has been hypothesized.

NILVAD protocol: a European multicentre double-blind placebo-controlled trial of nilvadipine in mild-to-moderate Alzheimer's disease

INTRODUCTION

This study is a European multicentre, randomised, double-blind, placebo-controlled trial investigating the efficacy and safety of nilvadipine as a disease course modifying treatment for mild-to-moderate Alzheimer's disease (AD) in a phase III study that will run for a period of 82 weeks with a treatment period of 78 weeks.

METHODS AND ANALYSIS

Adult patients, males and females over 50 years with mild-to-moderate AD as defined by the National Institute of Neurological and Communicative Disorders and Stroke/Alzheimer's disease and Related Disorders Association (NINCDS-ADRDA) criteria, will be included in the study. It aims to recruit a total of 500 patients with AD; 250 in the nilvadipine group and 250 in the placebo group. Participants will be randomised to receive nilvadipine, an 8 mg overencapsulated, sustained release capsule, or a matching overencapsulated placebo (sugar pill) for a period of 78 weeks of treatment. The primary efficacy outcome measure in this study is the change in cognitive function as assessed by the Alzheimer's disease Assessment Scale (ADAS-Cog 12) from baseline to the end of treatment duration (78 weeks). There are two key secondary outcome measures, the Clinical Dementia Rating Scale Sum of Boxes (CDR-sb) and the Disability Assessment for Dementia (DAD). If a statistically significant effect is seen in the primary outcome, CDR-sb will be considered to be a coprimary end point and only the DAD will contribute to the secondary outcome analysis.

ETHICS AND DISSEMINATION

The study and all subsequent amendments have received ethical approval within each participating country according to national regulations. Each participant will provide written consent to participate in the study. All participants will remain anonymised throughout and the results of the study will be published in an international peer-reviewed journal.

TRIAL REGISTRATION NUMBER

EUDRACT Reference Number: 2012-002764-27.

Calcium channel blockers and dementia

Degenerative dementia is mainly caused by Alzheimer's disease and/or cerebrovascular abnormalities. Disturbance of the intracellular calcium homeostasis is central to the pathophysiology of neurodegeneration. In Alzheimer's disease, enhanced calcium load may be brought about by extracellular accumulation of amyloid-β. Recent studies suggest that soluble forms facilitate influx through calcium-conducting ion channels in the plasma membrane, leading to excitotoxic neurodegeneration. Calcium channel blockade attenuates amyloid-β-induced neuronal decline in vitro and is neuroprotective in animal models. Vascular dementia, on the other hand, is caused by cerebral hypoperfusion and may benefit from calcium channel blockade due to relaxation of the cerebral vasculature. Several calcium channel blockers have been tested in clinical trials of dementia and the outcome is heterogeneous. Nimodipine as well as nilvadipine prevent cognitive decline in some trials, whereas other calcium channel blockers failed. In trials with a positive outcome, BP reduction did not seem to play a role in preventing dementia, indicating a direct protecting effect on neurons. An optimization of calcium channel blockers for the treatment of dementia may involve an increase of selectivity for presynaptic calcium channels and an improvement of the affinity to the inactivated state. Novel low molecular weight compounds suitable for proof-of-concept studies are now available.