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

Racial/Ethnic Disparities in Use of Angiotensin II Receptor Type 2/4 Stimulatory Vs. Inhibitory Antihypertensive Among Hypertensive Adults in the USA

OBJECTIVES

Studies showed angiotensin II type 2 receptor/angiotensin II type 4 receptor (AT2R/AT4R) stimulatory antihypertensive was associated with a lower risk of dementia and cognitive impairment compared to the inhibitory one. This study aimed to identify the racial and ethnic differences in using these agents among the USA adults with hypertension.

METHODS

A cross-sectional study was conducted using data from the Medical Expenditure Panel Survey (MEPS, 2016-2019). Individuals with a diagnosis of hypertension or self-reported hypertension and without dementia or Alzheimer's disease diagnosis were included in the analysis. We applied two multivariable logistic regressions to compare racial/ethnic differences in AT2R/AT4R stimulatory antihypertensive use and AT2R/AT4R inhibitory antihypertensive use, adjusting for covariates.

RESULTS

Twenty-four thousand five hundred eighty-one individuals with hypertension and without dementia or Alzheimer's disease were identified. Among non-Hispanic Whites, 72.39% were using AT2R/AT4R inhibitory antihypertensive agents, vs. 66.97% using AT2R/AT4R stimulatory antihypertensive agents. In contrast, both non-Hispanic Black and Asian Americans were using more AT2R/AT4R stimulatory agents than inhibitory ones (16.40% vs. 12.16% and 4.79% vs. 3.43%, respectively). Compared to non-Hispanic White, non-Hispanic Black (OR 1.980, 95% CI 1.839-2.132) and non-Hispanic Asian Americans (OR 1.545, 95% CI 1.356-1.761) were significantly associated with higher odds of prescribing AT2R/AT4R stimulatory agents, while Hispanics (OR 0.744, 95% CI 0.685-0.808) were associated with lower odds of prescribing AT2R/AT4R inhibitory agents compared to non-Hispanic Whites.

CONCLUSIONS

The results showed that the high-dementia risk populations like non-Hispanic Black and Asian American races are proportionally prescribed with higher use of low-dementia risk antihypertensive agents, compared to non-Hispanic Whites.

Antihypertensive drug classes and risk of incident dementia: a multinational population-based cohort study

BACKGROUND

Angiotensin-converting enzyme inhibitors (ACEIs) and angiotensin-II receptor blockers (ARBs) are first-line antihypertensive drugs for many patients, and influencing angiotensin systems may play a role in dementia risk. This study aimed to investigate whether exposure to different antihypertensive drug classes compared with ACEI affects the risk of dementia and pathological dementia subtypes in a large multinational database study.

METHODS

This was a multinational population-based cohort study using electronic health databases in Hong Kong, the UK, Sweden and Australia. A common protocol was used to harmonise the study design. An active comparator, a new user design, was applied to compare the risk of all-cause dementia between different antihypertensive drug classes, with secondary outcomes of Alzheimer's disease (AD) and vascular dementia (VaD). Adjusted Cox proportional hazards models with inverse probability of treatment weighting were used to generate results in each study site and were pooled in meta-analysis.

RESULTS

One million nine hundred twenty-five thousand, five hundred sixty-three individuals were included across the four databases with a median follow-up ranging from 5.6 to 8.4 years. Compared to ACEI, initiation with ARB was associated with a reduced risk of incident all-cause dementia [hazard ratio (HR): 0.92, 95% confidence interval (CI): 0.89-0.94] and VaD (HR 0.87, 95% CI 0.78-0.96) but not AD.

CONCLUSIONS

This is the largest multinational cohort study conducted to date investigating different classes of antihypertensive drugs and the risk of incident dementia. When initiating antihypertensives, physicians and patients should consider the reduced risk of all-cause dementia and VaD with ARB compared with ACEI in their risk-benefit assessment.

Comparative effects of angiotensin II stimulating and inhibiting antihypertensives on dementia risk: a systematic review and meta-analysis

Studies comparing the effects of Angiotensin II (Ang-II) stimulating and inhibiting antihypertensive medications (AHMs) on dementia risk have reported inconsistent findings. Based on the PRISMA guidelines, this study was performed to pool these findings. We searched PubMed, Scopus, Embase Ovid, PsycINFO, and CINAHL from inception to 22 May 2024 for randomised controlled trials (RCTs) and observational studies that compared the use of Ang-II stimulating (thiazides, Ang-II receptor blockers, and dihydropyridine calcium channel blockers) and inhibiting AHMs (β-blockers, angiotensin-converting enzyme inhibitors, and non-dihydropyridine calcium channel blockers) and the subsequent risk of developing dementia. Two reviewers independently performed study selection, data extraction, and quality assessment. Random effects meta-analysis models were used to calculate hazard ratios (HRs) or risk ratios (RRs) with their confidence intervals (CIs). All-cause dementia was the primary outcome. Alzheimer's disease (AD), vascular dementia (VD), and mild cognitive impairment (MCI) were secondary outcomes. We included 18 studies with 1,883,283 participants. Observational studies showed that the use of Ang-II stimulating AHMs reduced the risk of all-cause dementia by 13% (HR = 0.87; 95% CI = 0.82-0.93) compared with Ang-II inhibiting AHMs. The risk of AD was reduced by 12% (HR = 0.88; 95% CI = 0.86-0.90), VD by 19% (HR = 0.81; 95% CI = 0.72-0.91), and MCI by 24% (HR = 0.76; 95% CI = 0.68-0.85) in these studies. A meta-analysis of four RCTs revealed a non-significant 8% reduction in dementia risk with Ang-II stimulating AHMs versus control (RR = 0.92; 95% CI = 0.79-1.08). Observational evidence suggests that Ang-II stimulating AHMs may offer neuroprotective benefits relative to Ang-II inhibiting AHMs.

The Use of Antihypertensive Medication and In Vivo Alzheimer's Disease Pathology

OBJECTIVE

We investigated whether the use of antihypertensive medication (AHM) is associated with in vivo Alzheimer's Disease (AD) pathologies in older adults with hypertension and examined if the effect differs by drug-class and blood-brain barrier (BBB) permeability of the drug.

METHODS

This cross-sectional study recruited participants from the Korean Brain Aging Study for the Early Diagnosis and Prevention of Alzheimer's Disease. Participants comprised both cognitively normal and impaired older adults diagnosed with hypertension (n = 408). All participants underwent comprehensive clinical assessment and [11C] Pittsburgh Compound B positron emission tomography (PET) for measurement of cerebral β-amyloid (Aβ) deposition. Additionally, a subset of participants (n = 120) was subjected to [18F] AV-1451 PET to assess tau deposition.

RESULTS

The AHM group (n = 227) exhibited significantly lower Aβ deposition (B [SE] = -0.104 [0.037], p = 0.006) compared to the non-AHM group (n = 181), even after controlling for age, sex, apolipoprotein E ε4-positivity, vascular risk factors, and mean arterial blood pressure. Further analysis by AHM class showed an association between the use of renin-angiotensin system inhibitors (RASi) and less Aβ deposition (B [SE] = -0.143[0.049], p = 0.004). No significant relationships were observed between the use of BBB-permeable AHM and Aβ deposition. Additionally, associations between AHM use and tau deposition did not reach statistical significance.

INTERPRETATION

Our findings suggest that AHM use may be associated with lower Aβ burden in older adults with hypertension. Further studies exploring the underlying mechanism, particularly related to RASi, may provide insights into new therapeutic targets for AD. ANN NEUROL 2025.

Unveiling the potential of intranasal delivery of renin-angiotensin system drugs: Insights on the pharmacokinetics of irbesartan

The therapeutic interest of renin-angiotensin system (RAS) drugs for the treatment of neuroinflammation has been recently acknowledged. Nevertheless, most of them display limited passage across the blood-brain barrier (BBB). Therefore, this study investigated the potential of intranasal (IN) delivery of six RAS drugs to circumvent the BBB and attain the brain, envisioning its future use in central nervous system (CNS) neuroinflammatory diseases, such as Alzheimer's disease (AD). Captopril, enalaprilat, irbesartan, lisinopril, losartan and valsartan were firstly screened based on their impact on the viability of nasal, lung, and neuronal cell lines and their apparent permeability (Papp) across porcine olfactory mucosa. Irbesartan, identified as the one with the best safety and permeability balance, was selected for pharmacokinetic characterization following single and multidose IN administration to CD-1 mice. The results were compared to those obtained by intravenous (IV) injection to assess direct nose-to-brain drug delivery. Olfactory toxicity and anxiety were also evaluated after multidose IN treatment. Irbesartan IN administration significantly enhanced brain targeting, with a 3-fold increase in the maximum concentration (Cmax) and a 2.5-fold increase in the area under the curve (AUCt) in the brain compared to IV route. The drug exhibited a tmax of 15 min post-IN administration and achieved a brain targeting efficiency of 239.56%, with a significant direct transport percentage of 58.26%. Multidose administration indicated no systemic or tissue accumulation, with accumulation ratio (Rac) values below 1.0, and no significant olfactory toxicity. Overall, the study highlights the potential of IN delivery of irbesartan as a promising strategy to improve brain targeting and therapeutic outcomes in CNS diseases such as AD, providing an effective approach to bypass BBB limitations.

Association between risk of Alzheimer's disease and related dementias and angiotensin receptor Ⅱ blockers treatment for individuals with hypertension in high-volume claims data

BACKGROUND

Findings regarding the protective effect of Angiotensin II receptor blockers (ARBs) against Alzheimer's disease and related dementias (AD/ADRD) and cognitive decline have been inconclusive.

METHODS

Individuals with hypertension who do not have any prior ADRD diagnosis were included in this retrospective cohort study from Optum's de-identified Clinformatics® Data Mart. We identified antihypertensive medication (AHM) drug classes and subclassified ARBs by blood-brain barrier (BBB) permeability. We compared baseline characteristics and used the Kaplan-Meier (KM) survival curve and adjusted Cox proportional hazards (PH) model for survival analyses.

FINDINGS

From 6,390,826 individuals with hypertension, there were 1,839,176 ARB users, 3,366,841 non-ARB AHM users, and 1,184,809 AHM non-users. The unadjusted KM curve showed that ARB users had lower cumulative hazard than other AHM users or AHM non-users (P < 0.0001). In Cox PH analysis, ARB users showed a 20% lower adjusted hazard of developing ADRD compared to angiotensin-converting enzyme inhibitor (ACEI) users and a 29% and 18% reduced hazard when compared to non-ARB/ACEI AHM users and AHM non-users (all P < 0.0001). Consumption of BBB-crossing ARBs was linked to a lower hazard of ADRD development than non-BBB-crossing ARBs, undetermined ARBs, and non-consumption of AHMs by 11%, 25%, and 31% (all P < 0.0001).

INTERPRETATION

This study suggests that ARBs are superior to ACEIs, non-ARB/ACEI AHMs, or non-use of AHMs in reducing the hazard of ADRD among patients with hypertension. Also, BBB-permeability in ARBs was associated with lower ADRD incidence. There is no cure for AD, ADRD, or vascular dementia; hence, these findings are significant in preventing those disorders in an inexpensive, convenient, and safe way. Limitations in claims data should be considered when interpreting our findings.

FUNDING

This research was supported by the National Institute on Aging grants (R01AG084236, R01AG083039, RF1AG072799, R56AG074604).

The role of eprosartan in the management of essential hypertension: literature review and expert opinion

INTRODUCTION

Eprosartan is an angiotensin receptor blocker (ARB) used for management of essential hypertension. With unique pharmacological characteristics, dual action mechanism, and clinical effectiveness, eprosartan offers additional advantages over other ARBs in specific patient populations.

AREAS COVERED

A comprehensive review of the literature was performed across publicly available databases, with no time limitations, to ensure the inclusion of all relevant studies. The review focuses on presenting the efficacy and safety profile of eprosartan, alone or in combination with other agents. Additionally, it explores the etiology of hypertension concerning the structure and function of angiotensin II type 1 receptors. Further, the efficacy of eprosartan in special populations and its additional benefits are also discussed.

EXPERT OPINION

Eprosartan effectively reduces blood pressure (BP), with a 24-hour BP-lowering effect at 600 mg/day. Eprosartan demonstrates similar or better efficacy than other ARBs, such as telmisartan and losartan, particularly in managing coagulation-related abnormalities and peripheral resistance. In combination therapy, eprosartan with hydrochlorothiazide significantly enhances BP reduction. Eprosartan is well-tolerated, with a low incidence of adverse events, making it a reliable choice for long-term hypertension management across various patient populations, such as those with comorbid diabetes and renal disease and older adults.

Angiotensin Converting Enzyme (ACE) expression in microglia reduces amyloid β deposition and neurodegeneration by increasing SYK signaling and endolysosomal trafficking

Genome-wide association studies (GWAS) have identified many gene polymorphisms associated with an increased risk of developing Late Onset Alzheimer's Disease (LOAD). Many of these LOAD risk-associated alleles alter disease pathogenesis by influencing microglia innate immune responses and lipid metabolism. Angiotensin Converting Enzyme (ACE), a GWAS LOAD risk-associated gene best known for its role in regulating systemic blood pressure, also enhances innate immunity and lipid processing in peripheral myeloid cells, but a role for ACE in modulating the function of myeloid-derived microglia remains unexplored. Using novel mice engineered to express ACE in microglia and CNS associated macrophages (CAMs), we find that ACE expression in microglia reduces Aβ plaque load, preserves vulnerable neurons and excitatory synapses, and greatly reduces learning and memory abnormalities in the 5xFAD amyloid mouse model of Alzheimer's Disease (AD). ACE-expressing microglia show enhanced Aβ phagocytosis and endolysosomal trafficking, increased clustering around amyloid plaques, and increased SYK tyrosine kinase activation downstream of the major Aβ receptors, TREM2 and CLEC7A. Single microglia sequencing and digital spatial profiling identifies downstream SYK signaling modules that are expressed by ACE expression in microglia that mediate endolysosomal biogenesis and trafficking, mTOR and PI3K/AKT signaling, and increased oxidative phosphorylation, while gene silencing or pharmacologic inhibition of SYK activity in ACE-expressing microglia abrogates the potentiated Aβ engulfment and endolysosomal trafficking. These findings establish a role for ACE in enhancing microglial immune function and they identify a potential use for ACE-expressing microglia as a cell-based therapy to augment endogenous microglial responses to Aβ in AD.

The central renin-angiotensin system: A genetic pathway, functional decoding, and selective target engagement characterization in humans

Accumulating evidence suggests that the brain renin angiotensin system (RAS) plays a pivotal role in the regulation of cognition and behavior as well as in the neuropathology of neurological and mental disorders. The angiotensin II type 1 receptor (AT1R) mediates most functional and neuropathology-relevant actions associated with the central RAS. However, an overarching comprehension to guide translation and utilize the therapeutic potential of the central RAS in humans is currently lacking. We conducted a comprehensive characterization of the RAS using an innovative combination of transcriptomic gene expression mapping, image-based behavioral decoding, and pre-registered randomized controlled discovery-replication pharmacological resting-state functional magnetic resonance imaging (fMRI) trials (N = 132) with a selective AT1R antagonist. The AT1R exhibited a particular dense expression in a subcortical network encompassing the thalamus, striatum, and amygdalo-hippocampal formation. Behavioral decoding of the AT1R gene expression brain map showed an association with memory, stress, reward, and motivational processes. Transient pharmacological blockade of the AT1R further decreased neural activity in subcortical systems characterized by a high AT1R expression, while increasing functional connectivity in the cortico-basal ganglia-thalamo-cortical circuitry. Effects of AT1R blockade on the network level were specifically associated with the transcriptomic signatures of the dopaminergic, opioid, acetylcholine, and corticotropin-releasing hormone signaling systems. The robustness of the results was supported in an independent pharmacological fMRI trial. These findings present a biologically informed comprehensive characterization of the central AT1R pathways and their functional relevance on the neural and behavioral level in humans.

Intranasal irbesartan reverts cognitive decline and activates the PI3K/AKT pathway in an LPS-induced neuroinflammation mice model

BACKGROUND

New strategies are urgently needed to manage and delay the development of Alzheimer's disease (AD). Neuroinflammation is a significant contributor to cognitive decline in neurodegenerative diseases, including AD. Angiotensin receptor blockers (ARBs) and angiotensin converting enzyme inhibitors (ACEIs) protect hypertensive patients against AD, but the cellular and molecular mechanisms underlying these effects remain unknown. In light of this, the protective effects of three ARBs and three ACEIs against neuroinflammation and cognitive decline were investigated through comprehensive pharmacologicalin vitro/in vivoscreening.

METHODS

BV-2 microglia cells were exposed tolipopolysaccharide (LPS) and treated with ARBs and ACEIs to provide initial insights into the anti-inflammatory properties of the drugs. Subsequently, irbesartan was selected, and its efficacy was evaluated inC57/BL6 male miceintranasally administered with irbesartan and injected with LPS. Long-term memory and depressive-like behavior were evaluated; dendritic spines were measured as well as neuroinflammation, neurodegeneration and cognitive decline biomarkers.

RESULTS

Irbesartan mitigated memory loss and depressive-like behavior in mice treated with LPS, probably because itincreased spine density, ameliorated synapsis dysfunction and activated the PI3K/AKT pathway. Irbesartan elevated the levels of hippocampalsuperoxide dismutase2 andglutathione peroxidaseandsuppressed LPS-induced astrogliosis.

CONCLUSIONS

Overall, this study provides compelling evidence that multiple intranasal administrations of irbesartan can effectively prevent LPS-induced cognitive decline by activating pathways involved in neuroprotection and anti-inflammatory events. These findings underscore the potential of irbesartan as a preventive strategy against the development of AD and other neurodegenerative conditions associated with neuroinflammation.

Exposure to angiotensin-converting enzyme inhibitors that cross the blood-brain barrier and the risk of dementia among patients with human immunodeficiency virus

More than one million people in the United States and over 38 million people worldwide are living with human immunodeficiency virus (HIV) infection. Antiretroviral therapy (ART) greatly improves the health of people living with HIV (PLWH); however, the increased life longevity of PLWH has revealed consequences of HIV-associated comorbidities. HIV can enter the brain and cause inflammation even in individuals with well-controlled HIV infection. The quality of life for PLWH can be compromised by cognitive deficits and memory loss, termed HIV-associated neurological disorders (HAND). HIV-associated dementia is a related but distinct diagnosis. Common causes of dementia in PLWH are similar to the general population and can affect cognition. There is an urgent need to identify treatments for the aging PWLH population. We previously developed AI-based biomedical literature mining systems to uncover a potential novel connection between HAND the renin-angiotensin system (RAAS), which is a pharmacological target for hypertension. RAAS-targeting anti-hypertensives are gaining attention for their protective benefits in several neurocognitive disorders. To our knowledge, the effect of RAAS-targeting drugs on the cognition of PLWH development of dementia has not previously been analyzed. We hypothesized that exposure to angiotensin-converting enzyme inhibitors (ACEi) that cross the blood brain barrier (BBB) reduces the risk/occurrence of dementia in PLWH. We report a retrospective cohort study of electronic health records (EHRs) to examine the proposed hypothesis using data from the United States Department of Veterans Affairs, in which a primary outcome of dementia was measured in controlled cohorts of patients exposed to BBB-penetrant ACEi versus those unexposed to BBB-penetrant ACEi. The results reveal a statistically significant reduction in dementia diagnosis for PLWH exposed to BBB-penetrant ACEi. These results suggest there is a potential protective effect of BBB ACE inhibitor exposure against dementia in PLWH that warrants further investigation.

Angiotensin Receptor Blockers and Cognition: a Scoping Review

PURPOSE OF REVIEW

To provide an overview of the association between angiotensin II receptor blocker (ARB) use and cognitive outcomes.

RECENT FINDINGS

ARBs have previously shown greater neuroprotection compared to other anti-hypertensive classes. The benefits are primarily attributed to the ARB's effect on modulating the renin-angiotensin system via inhibiting the Ang II/AT1R pathway and activating the Ang II/AT2R, Ang IV/AT4R, and Ang-(1-7)/MasR pathways. These interactions are associated with pleiotropic neurocognitive benefits, including reduced β-amyloid accumulation and abnormal hyperphosphorylation of tau, ameliorated brain hypo-fusion, reduced neuroinflammation and synaptic dysfunction, better neurotoxin clearing, and blood-brain barrier function restoration. While ACEis also inhibit AT1R, they simultaneously lower Ang II and block the Ang II/AT2R and Ang IV/AT4R pathways that counterbalance the potential benefits. ARBs may be considered an adjunctive approach for neuroprotection. This preliminary evidence, coupled with their underlying mechanistic pathways, emphasizes the need for future long-term randomized trials to yield more definitive results.

Environmental, Sociocultural, Behavioral, and Biological Factors Associated with Cognitive Decline, Alzheimer's Disease, and Other Types of Dementia in Black Americans

Purpose of Review

This narrative review summarizes environmental, sociocultural, behavioral, and biological factors associated with cognitive decline and dementia in Black Americans.

Recent Findings

Variations in environmental factors (education, toxins) contribute to poor cognition in Blacks. Historical context, early-life educational experiences, and environmental exposures should be considered for addressing late-life cognitive disparities. Sociocultural (stress, discrimination, social networks, social activity, loneliness) and behavioral (depression, coping, health behaviors) factors can have positive and negative implications for cognitive aging. Given these factors are not consistently shown to play a role in maintaining cognition in Blacks, further examination is needed. Cardiometabolic conditions increase the risk of cognitive issues and are more common in Blacks; thus, examination of biological mechanisms (inflammation, vascular changes, etc.) warrants further study.

Summary

Future studies should explore the impact of education and segregation and identify mechanisms linking stress and discrimination to cognitive outcomes. Further, culturally tailored programs focused on preventative behaviors are needed to enhance health outcomes and reduce disparities.

Sex Differences in the Preventive Effect of Cardiovascular and Metabolic Therapeutics on Dementia

Dementia is a clinical syndrome characterized by progressive impairment of cognitive and functional abilities. As currently applied treatments for dementia can only delay the progression of dementia and cannot fundamentally cure it, much attention is being paid to reducing its incidence by preventing the associated risk factors. Cardiovascular and metabolic diseases are well-known risk factors for dementia, and many studies have attempted to prevent dementia by treating these risk factors. Growing evidence suggests that sex-based factors may play an important role in the pathogenesis of dementia. Therefore, a deeper understanding of the differences in the effects of drugs based on sex may help improve their effectiveness. In this study, we reviewed sex differences in the impact of therapeutics targeting risk factors for dementia, such as cardiovascular and metabolic diseases, to prevent the incidence and/or progression of dementia.

Soluble and insoluble protein aggregates, endoplasmic reticulum stress, and vascular dysfunction in Alzheimer's disease and cardiovascular diseases

Dementia refers to a particular group of symptoms characterized by difficulties with memory, language, problem-solving, and other thinking skills that affect a person's ability to perform everyday activities. Alzheimer's disease (AD) is the most common form of dementia, affecting about 6.2 million Americans aged 65 years and older. Likewise, cardiovascular diseases (CVDs) are a major cause of disability and premature death, impacting 126.9 million adults in the USA, a number that increases with age. Consequently, CVDs and cardiovascular risk factors are associated with an increased risk of AD and cognitive impairment. They share important age-related cardiometabolic and lifestyle risk factors, that make them among the leading causes of death. Additionally, there are several premises and hypotheses about the mechanisms underlying the association between AD and CVD. Although AD and CVD may be considered deleterious to health, the study of their combination constitutes a clinical challenge, and investigations to understand the mechanistic pathways for the cause-effect and/or shared pathology between these two disease constellations remains an active area of research. AD pathology is propagated by the amyloid β (Aβ) peptides. These peptides give rise to small, toxic, and soluble Aβ oligomers (SPOs) that are nonfibrillar, and it is their levels that show a robust correlation with the extent of cognitive impairment. This review will elucidate the interplay between the effects of accumulating SPOs in AD and CVDs, the resulting ER stress response, and their role in vascular dysfunction. We will also address the potential underlying mechanisms, including the possibility that SPOs are among the causes of vascular injury in CVD associated with cognitive decline. By revealing common mechanistic underpinnings of AD and CVD, we hope that novel experimental therapeutics can be designed to reduce the burden of these devastating diseases. Graphical abstract Alzheimer's disease (AD) pathology leads to the release of Aβ peptides, and their accumulation in the peripheral organs has varying effects on various components of the cardiovascular system including endoplasmic reticulum (ER) stress and vascular damage. Image created with BioRender.com.

Angiotensin-II stimulating vs. inhibiting antihypertensive drugs and the risk of Alzheimer's disease or related dementia in a large cohort of older patients with colorectal cancer

Background

Several previous studies showed that patients who received angiotensin II-stimulating antihypertensive medications had a lower incident dementia rate than those angiotensin II-inhibiting antihypertensive users, but no study has been conducted in long-term cancer survivors.

Objectives

To determine the risk of Alzheimer's disease (AD) and related dementia (ADRD) associated with the types of antihypertensive medications in a large cohort of survivors with colorectal cancer in 2007-2015 with follow-up from 2007 to 2016.

Methods

We identified 58,699 men and women with colorectal cancer aged 65 or older from the Surveillance, Epidemiology, and End Results (SEER)-Medicare linked database in 17 SEER areas in 2007-2015 with follow-up to 2016, who were free of any diagnosed ADRD at the baseline (within 12 months prior to and 12 months after the date of diagnosis for colorectal cancer). All patients who were defined as having hypertension by ICD diagnosis code or received antihypertensive drugs during this baseline 2-year period were classified into 6 groups based on whether they received angiotensin-II stimulating or inhibiting antihypertensive drugs.

Results

Crude cumulative incidence rates of AD and ADRD were similar between those who received angiotensin II-stimulating antihypertensive medications (4.3% and 21.7%) and those receiving angiotensin II-inhibiting antihypertensive medications (4.2% and 23.5%). As compared to patients who received angiotensin II-stimulating antihypertensive drugs, those who received angiotensin II-inhibiting antihypertensives were significantly more likely to develop AD (adjusted hazard ratio: 1.15, 95% CI: 1.01-1.32), vascular dementias (1.27, 1.06-1.53), and total ADRD (1.21, 1.14-1.28) after adjusting for potential confounders. These results remained similar after adjusting for medication adherence and considering death as a competing risk.

Conclusions

The risk of AD and ADRD in patients with hypertension who received angiotensin II-inhibiting antihypertensive medications was higher than in those receiving angiotensin II-stimulating antihypertensive drugs in patients with colorectal cancer.

The effect of race and co-morbidities on Alzheimer's disease based on Medicare data

INTRODUCTION

Alzheimer's disease (AD) incidence is thought to be higher among Black than White individuals.

METHODS

We studied the US Medicare population from 2000 to 2018. Cox regression was used to determine the roles of race and co-morbidities for AD incidence.

RESULTS

We studied 11,880,906 Medicare beneficiaries, with 774,548 AD cases. Hazard ratios (HRs) by increasing numbers of co-morbidities (1-7) were 1.51, 2.00, 2.55, 3.16, 2.89, 4.77, and 5.65. Among those with no co-morbidities, Black individuals had a lower rate than those who are White (HR = 0.69), while among those with one more co-morbidities, Black individuals had a higher rate (HR = 1.19). The presence of hypertension increased AD rates by 14% for White individuals, but 69% for those who are Black.

DISCUSSION

More co-morbidities was strongly associated with higher AD rates. The higher rates for Black versus White individuals was apparent only for those with co-morbidities and appears driven both by more co-morbidities, and the greater effect of hypertension.

HIGHLIGHTS

Black individuals have been shown to have higher Alzheimer's disease (AD) rates than those who are White. Some co-morbidities are known to increase AD risk. Among those In Medicare data with no co-morbidities, Black individuals have less risk than those who are White. Among those with co-morbidities, Black individuals have higher rates than those who are White. Hypertension results in a much stronger increase in AD risk for Black versus White individuals.

The effect of novel antihypertensive drug valsartan on lysozyme aggregation: A combined in situ and in silico study

Protein misfolding can result in amyloid fiber aggregation, which is associated with various types of diseases. Therefore, preventing or treating abnormally folded proteins may provide therapeutic intervention for these diseases. Valsartan (VAL) is an angiotensin II receptor blocker (ARB) that is used to treat hypertension. In this study, we examine the anti-aggregating effect of VAL against hen egg-white lysozyme (HEWL) amyloid fibrils through spectroscopy, docking, and microscopic analysis. In vitro formation of HEWL amyloid fibrils was indicated by increased turbidity, RLS (Rayleigh light scattering), and ThT fluorescence intensity. 10 μM VAL, amyloid/aggregation was inhibited up to 83% and 72% as measured by ThT and RLS respectively. In contrast, 100 μM VAL significantly increases the fibril aggregation of HEWL. CD spectroscopy results show a stabilization of HEWL α-helical structures in the presence of 10 μM VAL while the increase in β-sheet was detected at 100 μM concentration of VAL. The hydrophobicity of HEWL was increased at 100 μM VAL, suggesting the promotion of aggregation via its self-association. Steady-state quenching revealed that VAL and HEWL interact spontaneously via hydrogen bonds and van der Waals forces. Transmission electron microscopy (TEM) images illustrate that the needle-like fibers of HEWL amyloid were reduced at 10 μM VAL, while at 100 μM the fibrils of amyloid were increased. Additionally, our computational studies showed that VAL could bind to two binding sites within HEWL. In the BS-1 domain of HEWL, VAL binds to ASN⁵⁹, ILE⁹⁸, ILE⁵⁸, TRP¹⁰⁸, VAL¹⁰⁹, SER⁵⁰, ASP⁵², ASN⁵⁹, ALA¹⁰⁷, and TRP¹⁰⁸ residues with a binding energy of -9.72 kcal mol^-1. Also, it binds to GLU⁷, ALA¹⁰, ALA¹¹, CYS⁶, ARG¹²⁸, and ARG¹⁴ in the BS-2 domain with a binding energy of -5.89 kcal mol^-1. VAL, therefore, appears to have dual effect against HEWL aggregation. We suggest that VAL stabilizes HEWL's aggregation-prone region (APR) at 10 μM, preventing aggregation. Also, we assume that at 100 μM, VAL occupies BS-2 beside BS-1 and destabilizes the folding structure of HEWL, resulting in aggregation. Further studies are needed to investigate the mechanism of action and determine its potential side effects.

Blood-brain barrier permeable β-blockers linked to lower risk of Alzheimer's disease in hypertension

Alzheimer's disease is a neurodegenerative disorder in which the pathological accumulation of amyloid-β and tau begins years before symptom onset. Emerging evidence suggests that β-blockers (β-adrenergic antagonists) increase brain clearance of these metabolites by enhancing CSF flow. Our objective was to determine whether β-blocker treatments that easily cross the blood-brain barrier reduce the risk of Alzheimer's disease compared to less permeable β-blockers. Data from the Danish national registers were used to identify a retrospective cohort of individuals with hypertension, and those treated with β-blockers were included in the analysis. People with indications for β-blocker use other than hypertension (e.g. heart failure) were only retained in a sensitivity analysis. β-blockers were divided into three permeability groups: low, moderate and high. We used multivariable cause-specific Cox regression to model the effect of β-blocker blood-brain barrier permeability on time to dementia outcomes, adjusting for baseline comorbidities, demographics and socioeconomic variables. Death was modelled as a competing risk. The 10-year standardized absolute risk was estimated as the averaged person-specific risks per treatment. In a cohort of 69 081 (median age = 64.4 years, 64.8% female) people treated with β-blockers for hypertension, highly blood-brain barrier-permeable β-blockers were associated with reduced risk of Alzheimer's disease versus low permeability β-blockers (-0.45%, P < 0.036). This effect was specific to Alzheimer's diagnoses and did not extend to dementia in general. Propensity score analysis matching high and low blood-brain barrier-permeable patients also detected a decreased Alzheimer's risk (-0.92%, P < 0.001) in the high permeability group compared to the low, as did a 1-year landmark analysis (-0.57%, P < 0.029) in which events within the first year of follow-up were ignored as likely unrelated to treatment. Our results suggest that amongst people taking β-blockers for hypertension, treatment with highly blood-brain barrier permeable β-blockers reduces the risk of Alzheimer's disease compared to low permeability drugs. Our findings support the hypothesis that highly permeable β-blockers protect against Alzheimer's disease by promoting waste brain metabolite clearance.

Effect of Antihypertensive Drug (Chlorothiazide) on Fibrillation of Lysozyme: A Combined Spectroscopy, Microscopy, and Computational Study

Amyloid fibrils abnormally accumulate together in the human body under certain conditions, which can result in lethal conditions. Thus, blocking this aggregation may prevent or treat this disease. Chlorothiazide (CTZ) is a diuretic and is used to treat hypertension. Several previous studies suggest that diuretics prevent amyloid-related diseases and reduce amyloid aggregation. Thus, in this study we examine the effects of CTZ on hen egg white lysozyme (HEWL) aggregation using spectroscopic, docking, and microscopic approaches. Our results showed that under protein misfolding conditions of 55 °C, pH 2.0, and 600 rpm agitation, HEWL aggregated as evidenced by the increased turbidity and Rayleigh light scattering (RLS). Furthermore, thioflavin-T, as well as trans electron microscope (TEM) analysis confirmed the formation of amyloid structures. An anti-aggregation effect of CTZ is observed on HEWL aggregations. Circular dichroism (CD), TEM, and Thioflavin-T fluorescence show that both CTZ concentrations reduce the formation of amyloid fibrils as compared to fibrillated. The turbidity, RLS, and ANS fluorescence increase with CTZ increasing. This increase is attributed to the formation of a soluble aggregation. As evidenced by CD analysis, there was no significant difference in α-helix content and β-sheet content between at 10 µM CTZ and 100 µM. A TEM analysis of HEWL coincubated with CTZ at different concentrations validated all the above-mentioned results. The TEM results show that CTZ induces morphological changes in the typical structure of amyloid fibrils. The steady-state quenching study demonstrated that CTZ and HEWL bind spontaneously via hydrophobic interactions. HEWL-CTZ also interacts dynamically with changes in the environment surrounding tryptophan. Computational results revealed the binding of CTZ to ILE⁹⁸, GLN⁵⁷, ASP⁵², TRP¹⁰⁸, TRP⁶³, TRP⁶³, ILE⁵⁸, and ALA¹⁰⁷ residues in HEWL via hydrophobic interactions and hydrogen bonds with a binding energy of -6.58 kcal mol^-1. We suggest that at 10 µM and 100 μM, CTZ binds to the aggregation-prone region (APR) of HEWL and stabilizes it, thus preventing aggregation. Based on these findings, we can conclude that CTZ has antiamyloidogenic activity and can prevent fibril aggregation.

Hypertension and hyperhomocysteinemia as modifiable risk factors for Alzheimer's disease and dementia: New evidence, potential therapeutic strategies, and biomarkers

This review summarizes recent evidence on how mid-life hypertension, hyperhomocysteinemia (HHcy) and blood pressure variability, as well as late-life hypotension, exacerbate Alzheimer's disease (AD) and dementia risk. Intriguingly, HHcy also increases the risk for hypertension, revealing the importance of understanding the relationship between comorbid cardiovascular risk factors. Hypertension-induced dementia presents more evidently in women, highlighting the relevance of sex differences in the impact of cardiovascular risk. We summarize each major antihypertensive drug class's effects on cognitive impairment and AD pathology, revealing how carbonic anhydrase inhibitors, diuretics modulating cerebral blood flow, have recently gained preclinical evidence as promising treatment against AD. We also report novel vascular biomarkers for AD and dementia risk, highlighting those associated with hypertension and HHcy. Importantly, we propose that future studies should consider hypertension and HHcy as potential contributors to cognitive impairment, and that uncovering the underlying molecular mechanisms and biomarkers would aid in the identification of preventive strategies.

Recent Updates on the Development of Therapeutics for the Targeted Treatment of Alzheimer's Disease

Alzheimer's disease (AD) is a complicated, multifaceted, irreversible, and incurable neurotoxic old age illness. Although NMDA (N-methyl D-aspartate)-receptor antagonists, cholinesterase repressors, and their pairings have been approved for the treatment, they are useful for short symptomatic relief. Researchers throughout the globe have been constantly working to uncover the therapy of Alzheimer's disease as new candidates must be determined, and newer treatment medicines must be developed. The aim of this review is to address recent advances in medication research along with new Alzheimer's disease therapy for diverse targets. Information was gathered utilizing a variety of internet resources as well as websites, such as ALZFORUM (alzforum.org) and clinicaltrials.gov. In contrast to other domains, the proposed medicines target amyloids (secretases, A42 generation, neuroinflammation, amyloid precipitation, and immunization), tau proteins (tau phosphorylation/aggregation and immunotherapy), and amyloid deposition. Despite tremendous advancement in our understanding of the underlying pathophysiology of Alzheimer's disease, the FDA (Food and Drug Administration) only approved aducanumab for diagnosis and treatment in 2003. Hence, novel treatment tactics are needed to find and develop therapeutic medicines to combat Alzheimer's disease.

Deciphering mechanisms of action of ACE inhibitors in neurodegeneration using Drosophila models of Alzheimer's disease

Alzheimer's disease (AD) is a devastating neurodegenerative disorder for which there is no cure. Recently, several studies have reported a significant reduction in the incidence and progression of dementia among some patients receiving antihypertensive medications such as angiotensin-converting enzyme inhibitors (ACE-Is) and angiotensin receptor blockers (ARBs). Why these drugs are beneficial in some AD patients and not others is unclear although it has been shown to be independent of their role in regulating blood pressure. Given the enormous and immediate potential of ACE-Is and ARBs for AD therapeutics it is imperative that we understand how they function. Recently, studies have shown that ACE-Is and ARBs, which target the renin angiotensin system in mammals, are also effective in suppressing neuronal cell death and memory defects in Drosophila models of AD despite the fact that this pathway is not conserved in flies. This suggests that the beneficial effects of these drugs may be mediated by distinct and as yet, identified mechanisms. Here, we discuss how the short lifespan and ease of genetic manipulations available in Drosophila provide us with a unique and unparalleled opportunity to rapidly identify the targets of ACE-Is and ARBs and evaluate their therapeutic effectiveness in robust models of AD.

In the prevention of dementia, the focus should be on early and consistent treatment of hypertension

The brain is among the target organs of hypertension. Patients with hypertension have a higher risk of developing stroke as well as experiencing a decline in cognitive functions and dementia. Changes in the white matter and atrophy of the grey matter of the brain induced by high blood pressure develop insidiously since the onset of hypertension, even in young individuals. The effect of high blood pressure on the vessel wall cumulates in time; therefore, hypertension in younger people implies an increased risk of dementia in older age. Hypertension in young age cannot be considered a benign condition. Hypertension in middle age increases the risk of dementia by 61 %. Consistent and early hypertension control can reverse the adverse development towards dementia and lack of self-sufficiency in the patient. Data comparing individual antihypertensive drugs in terms of preventing dementia are scarce. However, renin angiotensin system blockers have been found to protect against Alzheimer's disease more than other classes of antihypertensive drugs. To achieve rapid and effective hypertension control, a combination of antihypertensive drugs is usually required. Using a fixed-dose triple combination of perindopril, indapamide, and amlodipine, blood pressure targets of < 130/80 mm Hg can be achieved within three months in 93 % of patients.

A risk prediction model based on machine learning for early cognitive impairment in hypertension: Development and validation study

Background

Clinical practice guidelines recommend early identification of cognitive impairment in individuals with hypertension with the help of risk prediction tools based on risk factors.

Objective

The aim of this study was to develop a superior machine learning model based on easily collected variables to predict the risk of early cognitive impairment in hypertensive individuals, which could be used to optimize early cognitive impairment risk assessment strategies.

Methods

For this cross-sectional study, 733 patients with hypertension (aged 30-85, 48.98% male) enrolled in multi-center hospitals in China were divided into a training group (70%) and a validation group (30%). After least absolute shrinkage and selection operator (LASSO) regression analysis with 5-fold cross-validation determined the modeling variables, three machine learning classifiers, logistic regression (LR), XGBoost (XGB), and gaussian naive bayes (GNB), were developed. The area under the ROC curve (AUC), accuracy, sensitivity, specificity, and F1 score were used to evaluate the model performance. Shape Additive explanation (SHAP) analysis was performed to rank feature importance. Further decision curve analysis (DCA) assessed the clinical performance of the established model and visualized it by nomogram.

Results

Hip circumference, age, education levels, and physical activity were considered significant predictors of early cognitive impairment in hypertension. The AUC (0.88), F1 score (0.59), accuracy (0.81), sensitivity (0.84), and specificity (0.80) of the XGB model were superior to LR and GNB classifiers.

Conclusion

The XGB model based on hip circumference, age, educational level, and physical activity has superior predictive performance and it shows promise in predicting the risk of cognitive impairment in hypertensive clinical settings.

Neuroprotective effect of angiotensin II receptor blockers on the risk of incident Alzheimer's disease: A nationwide population-based cohort study

Background

Recent studies on renin-angiotensin system (RAS) inhibitors have reported a reduced risk of Alzheimer's disease (AD). Nevertheless, the effect of RAS inhibitor type and blood-brain barrier (BBB) permeability on the risk of AD is still unknown.

Objectives

To assess the effects of RAS inhibitors on the risk of AD based on the type and BBB permeability and investigate the cumulative duration-response relationship.

Methods

This was a population-based retrospective cohort study using the Korean Health Insurance Review and Assessment database records from 2008 to 2019. The data of patients diagnosed with ischemic heart disease between January 2009 and June 2009 were identified for inclusion in the analyses. Propensity score matching was used to balance RAS inhibitor users with non-users. The association between the use of RAS inhibitors and incident AD was evaluated using a multivariate Cox proportional hazard regression model. The results are presented in adjusted hazard ratios (aHRs) and 95% confidence intervals (CIs).

Results

Among the 57,420 matched individuals, 7,303 developed AD within the follow-up period. While the use of angiotensin-converting enzyme inhibitors (ACEIs) was not significantly associated with AD risk, the use of angiotensin II receptor blockers (ARBs) showed a significant association with reduced risk of incident AD (aHR = 0.94; 95% CI = 0.90-0.99). Furthermore, the use of BBB-crossing ARBs was associated with a lower risk of AD (aHR = 0.83; 95% CI = 0.78-0.88) with a cumulative duration-response relationship. A higher cumulative dose or duration of BBB-crossing ARBs was associated with a gradual decrease in AD risk (P for trend < 0.001). No significant association between the use of ACEIs and the risk of AD was observed regardless of BBB permeability.

Conclusion

Long-term use of BBB-crossing ARBs significantly reduced the risk of AD development. The finding may provide valuable insight into disease-modifying drug options for preventing AD in patients with cardiovascular diseases.

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.

Migraine Pharmacological Treatment and Cognitive Impairment: Risks and Benefits

Migraine is a common neurological disorder impairing the quality of life of patients. The condition requires, as an acute or prophylactic line of intervention, the frequent use of drugs acting on the central nervous system (CNS). The long-term impact of these medications on cognition and neurodegeneration has never been consistently assessed. The paper reviews pharmacological migraine treatments and discusses their biological and clinical effects on the CNS. The different anti-migraine drugs show distinct profiles concerning neurodegeneration and the risk of cognitive deficits. These features should be carefully evaluated when prescribing a pharmacological treatment as many migraineurs are of scholar or working age and their performances may be affected by drug misuse. Thus, a reconsideration of therapy guidelines is warranted. Furthermore, since conflicting results have emerged in the relationship between migraine and dementia, future studies must consider present and past pharmacological regimens as potential confounding factors.

Vulnerability to Hypertension Is a Major Determinant of Racial Disparities in Alzheimer's Disease Risk

BACKGROUND

Higher incidence levels of Alzheimer's disease (AD) in Black Americans are well documented. However, quantitative explanations of this disparity in terms of risk-factor diseases acting through well-defined pathways are lacking.

METHODS

We applied a Blinder-Oaxaca-based algorithm modified for censored data to a 5% random sample of Medicare beneficiaries age 65+ to explain Black/White disparities in AD risk in terms of differences in exposure and vulnerability to morbidity profiles based on 10 major AD-risk-related diseases.

RESULTS

The primary contribution to racial disparities in AD risk comes from morbidity profiles that included hypertension with about 1/5th of their contribution due to differences in prevalence (exposure effect) and 4/5ths to differences in the effects of the morbidity profile on AD risk (vulnerability effect). In total, disease-related effects explained a higher proportion of AD incidence in Black Americans than in their White counterparts.

CONCLUSIONS

Disease-related causes may represent some of the most straightforward targets for targeted interventions aimed at the reduction of racial disparities in health among US older adults. Hypertension is a manageable and potentially preventable condition responsible for the majority of the Black/White differences in AD risk, making mitigation of the role of this disease in engendering higher AD incidence in Black Americans a prominent concern.

KG-Predict: A knowledge graph computational framework for drug repurposing

The emergence of large-scale phenotypic, genetic, and other multi-model biochemical data has offered unprecedented opportunities for drug discovery including drug repurposing. Various knowledge graph-based methods have been developed to integrate and analyze complex and heterogeneous data sources to find new therapeutic applications for existing drugs. However, existing methods have limitations in modeling and capturing context-sensitive inter-relationships among tens of thousands of biomedical entities. In this paper, we developed KG-Predict: a knowledge graph computational framework for drug repurposing. We first integrated multiple types of entities and relations from various genotypic and phenotypic databases to construct a knowledge graph termed GP-KG. GP-KG was composed of 1,246,726 associations between 61,146 entities. KG-Predict then aggregated the heterogeneous topological and semantic information from GP-KG to learn low-dimensional representations of entities and relations, and further utilized these representations to infer new drug-disease interactions. In cross-validation experiments, KG-Predict achieved high performances [AUROC (the area under receiver operating characteristic) = 0.981, AUPR (the area under precision-recall) = 0.409 and MRR (the mean reciprocal rank) = 0.261], outperforming other state-of-art graph embedding methods. We applied KG-Predict in identifying novel repositioned candidate drugs for Alzheimer's disease (AD) and showed that KG-Predict prioritized both FDA-approved and active clinical trial anti-AD drugs among the top (AUROC = 0.868 and AUPR = 0.364).

Validation of myasthenia gravis diagnosis in the older Medicare population

INTRODUCTION/AIMS

Administrative health data has been increasingly used to study the epidemiology of myasthenia gravis (MG) but a case ascertainment algorithm is lacking. We aimed to develop a valid algorithm for identifying MG patients in the older population with Medicare coverage.

METHODS

Local older patients (age ≥65) who received healthcare at the Cleveland Clinic and possessed Medicare coverage in 2014 and 2015 were selected. Potential MG patients were identified by using a combination of ICD9 or ICD10 codes for MG and MG-related text-word search. Diagnosis was categorized as "definite MG", "possible MG" or "non-MG" after review of clinical summaries by 5 neuromuscular specialists. Performances of various algorithms were tested by use of the definite MG cohort as a reference standard, and calculation of sensitivity, specificity, and predictive values.

RESULTS

A total of 118 988 local older patients with Medicare coverage were identified. Usage of MG ICD codes and text-word search resulted in 125 patients with definite and 67 with possible MG. A total of 45 algorithms involving ICD usage, medication prescription, and specialty visit were tested. The best performing algorithm was identified as 2 office visits using MG ICD codes separated by at least 4 weeks or 1 hospital discharge and 1 office visit each using MG ICD codes separated by at least 4 weeks within the two-year period, resulting in a sensitivity and positive predictive value of 80% for identifying definite MG patients.

DISCUSSION

Algorithms using ICD codes can reliably identify patients with MG with a high degree of accuracy.

Targeting brain Renin-Angiotensin System for the prevention and treatment of Alzheimer's disease: Past, present and future

Alzheimer's disease (AD) is a well-known neurodegenerative disease characterized by the presence of two main hallmarks - Tau hyperphosphorylation and Aβ deposits. Notwithstanding, in the last few years the scientific evidence about the drivers of AD have been changing and nowadays age-related vascular alterations and several cardiovascular risk factors have been shown to trigger the development of AD. In this context, drugs targeting the Renin Angiotensin System (RAS), commonly used for the treatment of hypertension, are evidencing a high potential to delay AD development due to their action on brain RAS. Indeed, the ACE 1/Ang II/AT1R axis is believed to be upregulated in AD and to be responsible for deleterious effects such as increased oxidative stress, neuroinflammation, blood-brain barrier (BBB) hyperpermeability, astrocytes dysfunction and a decrease in cerebral blood flow. In contrast, the alternative axis - ACE 1/Ang II/AT2R; ACE 2/Ang (1-7)/MasR; Ang IV/ AT4R(IRAP) - seems to counterbalance the deleterious effects of the principal axis and to exert beneficial effects on memory and cognition. Accordingly, retrospective studies demonstrate a reduced risk of developing AD among people taking RAS medication as well as several in vitro and in vivo pre-clinical studies as it is herein critically reviewed. In this review, we first revise, at a glance, the pathophysiology of AD focused on its classic hallmarks. Secondly, an overview about the impact of the RAS on the pathophysiology of AD is also provided, focused on their four essential axes ACE 1/Ang II/AT2R; ACE 2/Ang (1-7)/MasR; Ang IV/ AT4R(IRAP) and ACE 1/Ang II/AT1R. Finally, the therapeutic potential of available drugs targeting RAS on AD, namely angiotensin II receptor blockers (ARBs) and angiotensin converting enzyme inhibitors (ACEIs), is highlighted and data supporting this hope will be presented, from in vitro and in vivo pre-clinical to clinical studies.

Dysregulation of ACE-1 in normal aging and the early stages of Alzheimer's disease

An imbalance in the renin-angiotensin system (RAS) is associated with cognitive decline and disease pathology in Alzheimer's disease (AD). In this study, we have investigated changes in the brain angiotensin-converting enzyme-1 (ACE-1) and angiotensin-II (Ang-II), and the counter-regulatory angiotensin-converting enzyme-2 (ACE-2), in the frontal and temporal cortex during normal aging and in the early stages of AD. We studied a cohort of normal aging (n=121) (19-95y age-at-death) from the Sudden Death Brain Bank, University of Edinburgh, UK, and AD and age-matched controls (n=60) from the South West Dementia Brain Bank, University of Bristol, UK, stratified according to Braak tangle stage (BS): 0-II, III-IV (intermediate disease) and V-VI (end-stage disease). ACE-1 and ACE-2 enzyme activity were measured using fluorogenic peptide activity assays. ACE-1, ACE-2, and angiotensin-II (Ang-II) protein level was measured by ELISA. In both regions, ACE-1 protein and Ang-II levels correlated positively with age whereas ACE-1 enzyme activity was inversely related to age. ACE-1 protein correlated positively with Ang-II, whilst ACE-1 activity correlated inversely with Ang-II in normal ageing. ACE-1 enzyme activity was elevated at an early/intermediate stage i.e. BS III-IV compared to BS 0-II in the temporal cortex in AD. ACE-2 protein and enzyme activity were unchanged with aging and in AD. In conclusion, ACE-1 activity is induced in the early stages of AD independently from normal physiological age-related changes in ACE-1 protein.

Hypertension-induced cognitive impairment: from pathophysiology to public health

Hypertension affects two-thirds of people aged >60 years and significantly increases the risk of both vascular cognitive impairment and Alzheimer's disease. Hypertension compromises the structural and functional integrity of the cerebral microcirculation, promoting microvascular rarefaction, cerebromicrovascular endothelial dysfunction and neurovascular uncoupling, which impair cerebral blood supply. In addition, hypertension disrupts the blood-brain barrier, promoting neuroinflammation and exacerbation of amyloid pathologies. Ageing is characterized by multifaceted homeostatic dysfunction and impaired cellular stress resilience, which exacerbate the deleterious cerebromicrovascular effects of hypertension. Neuroradiological markers of hypertension-induced cerebral small vessel disease include white matter hyperintensities, lacunar infarcts and microhaemorrhages, all of which are associated with cognitive decline. Use of pharmaceutical and lifestyle interventions that reduce blood pressure, in combination with treatments that promote microvascular health, have the potential to prevent or delay the pathogenesis of vascular cognitive impairment and Alzheimer's disease in patients with hypertension.

Frailty Modifies the Association of Hypertension With Cognition in Older Adults: Evidence From the ELSI-Brazil

BACKGROUND

The relationship between hypertension and cognition in later life is controversial. We investigated whether the association of hypertension with cognition differs in older adults according to the frailty status using cross-sectional data from the Brazilian Longitudinal Study of Aging, a nationally representative sample of adults aged ≥50 years.

METHOD

Hypertension was defined by a medical diagnosis or measured blood pressure ≥140/90 mm Hg. Frailty status was assessed using the Cardiovascular Health Study criteria. We estimated the association of hypertension and systolic and diastolic blood pressure with global cognition, orientation, memory, and verbal fluency z-scores, using multiple linear regression models. We also investigated interactions between hypertension and frailty on cognitive performance and impairment.

RESULTS

We evaluated 8609 participants (mean age = 61.9 ± 9.6 years, 53% women). Participants with hypertension (59% of adults aged 50-64 and 77% of those aged ≥65 years) had poorer scores for global cognitive performance than those without hypertension, especially among adults aged 50-64 years (β = -0.09; 95% confidence interval = -0.15, -0.04; p = .001). However, frailty modified the associations of hypertension with cognitive performance and impairment in those aged ≥65 years (p-values for interaction = .01 and .02, respectively). Among nonfrail older adults, hypertension was associated with cognitive impairment. In contrast, among frail older adults, hypertension was related to better global and memory cognitive z-scores.

CONCLUSIONS

Hypertension was associated with worse cognitive performance. Among older adults, hypertension was related to cognitive impairment only in nonfrail participants. Frailty evaluation may help clinicians offer personalized hypertension management in older adults.

Blood-Brain Barrier Crossing Renin-Angiotensin Drugs and Cognition in the Elderly: A Meta-Analysis

[Figure: see text].

Association between renin-angiotensin-aldosterone system inhibitors and risk of dementia: A meta-analysis

OBJECTIVE

To evaluate the association of all RAAS inhibitors, ACE inhibitors (ACEIs) and angiotensin II receptor blockers (ARBs) on dementia onset (any dementia, Alzheimer's disease and vascular dementia) using a meta-analytic approach.

METHODS

A systematic MEDLINE search was carried out to identify all observational studies published up to the 30th September 2020 evaluating the association between RAAS inhibitors and risk of dementia. Studies were included if original investigations considering incident dementia cases, with ACEIs and/or ARBs as exposure and other antihypertensives (AHs) use as reference, and if reporting association estimates and relative variability measures. Random effect pooled relative risks (pRR) and the corresponding 95% confidence intervals (95%CI) were calculated according to DerSimonian and Laird's (DL) or to Hartung Knapp Sidik Jonkman (HKSJ) method depending on the number of studies and between-studies heterogeneity. A linear mixed meta-regression model (MM) was applied to take into account correlation among association estimates from the same study.

RESULTS

15 studies were included in the meta-analysis. ARBs but not ACEIs' use led to a significant reduction of the risk of any dementia (pRR 0.78, 95%CI_MM 0.70-0.87) and Alzheimer's disease (pRR 0.73, 95%CI_MM 0.60-0.90). Moreover, when compared to ACEIs, ARBs reduced of 14% the risk of any dementia (pRR 0.86, 95%CI_DL 0.79-0.94).

CONCLUSIONS

ARBs but not ACEIs led to a reduction in the risk of any dementia. The difference between ARBs and ACEIs in terms of preventive effectiveness could be due to distinct profiles of antagonism towards independent receptor pathways or to differential influences on amyloid metabolism.

Association between exenatide use and incidence of Alzheimer's disease

INTRODUCTION

Recent developments suggest that insulin-sensitizing agents used to treat type II diabetes (T2DM) may also prove useful in reducing the risk of Alzheimer's disease (AD). The objective of this study is to analyze the association between exenatide use among Medicare beneficiaries with T2DM and the incidence of AD.

METHODS

We performed a retrospective cohort analysis on claims data from a 20% random sample of Medicare beneficiaries with T2DM from 2007 to 2013 (n = 342,608). We compared rates of incident AD between 2009 and 2013 according to exenatide use in 2007-2008, measured by the number of 30-day-equivalent fills. We adjusted for demographics, comorbidities, and use of other drugs. Unmeasured confounding was assessed with an instrumental variables approach.

RESULTS

The sample was mostly female (65%), White (76%), and 74 years old on average. Exenatide users were more likely to be male (38% vs. 35%), White (87% vs. 76%), and younger (by 4.2 years) than non-users. Each additional 30-day-equivalent claim was associated with a 2.4% relative reduction in incidence (odds ratio 0.976; 95% confidence interval 0.963-0.989; P < .001). There was no evidence of unmeasured confounding.

DISCUSSION

Exenatide use is associated with a reduced incidence of AD among Medicare beneficiaries aged 65 years or older with T2DM. The association shown in this study warrants consideration by clinicians prescribing insulin sensitizing agents to patients.

The use of angiotensin-converting enzyme inhibitors vs. angiotensin receptor blockers and cognitive decline in Alzheimer's disease: the importance of blood-brain barrier penetration and APOE ε4 carrier status

Background

The antihypertensive angiotensin receptor blockers (ARBs) and angiotensin-converting enzyme inhibitors (ACE-Is) have similar indications and mechanisms of action, but prior work suggests divergence in their effects on cognition.

Methods

Participants in the National Alzheimer’s Coordinating Center database with a clinical diagnosis of dementia due to Alzheimer’s disease (AD) using an ACE-I or an ARB at any visit were selected. The primary outcome was delayed recall memory on the Wechsler Memory Scale Revised – Logical Memory IIA. Other cognitive domains were explored, including attention and psychomotor processing speed (Trail Making Test [TMT]-A and Digit Symbol Substitution Test [DSST]), executive function (TMT-B), and language and semantic verbal fluency (Animal Naming, Vegetable Naming, and Boston Naming Tests). Random slopes mixed-effects models with inverse probability of treatment weighting were used, yielding rate ratios (RR) or regression coefficients (B), as appropriate to the distribution of the data. Apolipoprotein (APOE) ε4 status and blood-brain barrier (BBB) penetrance were investigated as effect modifiers.

Results

Among 1689 participants with AD, ARB use (n = 578) was associated with 9.4% slower decline in delayed recall performance over a mean follow-up of 2.28 years compared with ACE-I use (n = 1111) [RR = 1.094, p = 0.0327]; specifically, users of BBB-crossing ARBs (RR = 1.25, p = 0.002), BBB-crossing ACE-Is (RR = 1.16, p = 0.010), and non-BBB-crossing ARBs (RR = 1.20, p = 0.005) had better delayed recall performance over time compared with non-BBB-crossing ACE-I users. An interaction with APOE ε4 status (drug × APOE × time RR = 1.196, p = 0.033) emerged; ARBs were associated with better delayed recall scores over time than ACE-Is in non-carriers (RR = 1.200, p = 0.003), but not in carriers (RR = 1.003, p = 0.957). ARB use was also associated with better performance over time on the TMT-A (B = 2.023 s, p = 0.0004) and the DSST (B = 0.573 symbols, p = 0.0485), and these differences were significant among APOE ε4 non-carriers (B = 4.066 s, p = 0.0004; and B = 0.982 symbols, p = 0.0230; respectively). Some differences were seen also in language and verbal fluency among APOE ε4 non-carriers.

Conclusions

Among APOE ε4 non-carriers with AD, ARB use was associated with greater preservation of memory and attention/psychomotor processing speed, particularly compared to ACE-Is that do not cross the blood-brain-barrier.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13195-021-00778-8.

Recent advances on drug development and emerging therapeutic agents for Alzheimer's disease

Alzheimer's disease (AD) is a neurodegenerative old age disease that is complex, multifactorial, unalterable, and progressive in nature. The currently approved therapy includes cholinesterase inhibitors, NMDA-receptor antagonists and their combination therapy provides only temporary symptomatic relief. Sincere efforts have been made by the researchers globally to identify new targets, discover, and develop novel therapeutic agents for the treatment of AD. This brief review article is intended to cover the recent advances in drug development and emerging therapeutic agents for AD acting at different targets. The article is compiled using various scientific online databases and by referring to clinicaltrials.gov and ALZFORUM (alzforum.org) websites. The upcoming therapies act on one or more targets including amyloids (secretases, Aβ₄₂ production, amyloid deposition, and immunotherapy), tau proteins (tau phosphorylation/aggregation and immunotherapy) and neuroinflammation in addition to other miscellaneous targets. Despite the tremendous improvement in our understanding of the underlying pathophysiology of AD, only aducanumab was approved by FDA for the treatment of AD in 18 years i.e., since 2003. Hence, it is concluded that novel therapeutic strategies are required to discover and develop therapeutic agents to fight against the century old AD.

Drug therapies for chronic conditions and risk of Alzheimer's disease and related dementias: A scoping review

INTRODUCTION

Most older Americans use drug therapies for chronic conditions. Several are associated with risk of Alzheimer's disease and related dementias (ADRD).

METHODS

A scoping review was used to identify drug classes associated with increasing or decreasing ADRD risk. We analyzed size, type, and findings of the evidence.

RESULTS

We identified 29 drug classes across 11 therapeutic areas, and 404 human studies. Most common were studies on drugs for hypertension (93) or hyperlipidemia (81). Fewer than five studies were identified for several anti-diabetic and anti-inflammatory drugs. Evidence was observational only for beta blockers, proton pump inhibitors, benzodiazepines, and disease-modifying anti-rheumatic drugs. For 13 drug classes, 50% or more of the studies reported consistent direction of effect on risk of ADRD.

DISCUSSION

Future research targeting drug classes with limited/non-robust evidence, examining sex, racial heterogeneity, and separating classes by molecule, will facilitate understanding of associated risk, and inform clinical and policy efforts to alleviate the growing impact of ADRD.

Associations between brain amyloid accumulation and the use of angiotensin-converting enzyme inhibitors versus angiotensin receptor blockers

Some studies suggest that angiotensin II type 1 receptor blockers (ARBs) may protect against memory decline more than angiotensin-converting enzyme inhibitors (ACE-Is), but few have examined possible mechanisms. We assessed longitudinal differences between ARB versus ACE-I users in global and sub-regional amyloid-β accumulation by ¹⁸F-florbetapir. In cognitively normal older adults (n= 142), propensity-weighted linear mixed-effects models showed that ARB versus ACE-I use was associated with slower amyloid-β accumulation in the cortex, and specifically in the caudal anterior cingulate and precuneus, and in the precentral and postcentral gyri. In amyloid-positive participants with Alzheimer's disease dementia or mild cognitive impairment (n = 169), ARB versus ACE-I use was not associated with different rates of amyloid-β accumulation. Apolipoprotein E ε4 carrier status explained some heterogeneity in the different rates of amyloid-β accumulation between users of ARBs versus ACE-Is in the study. Replicative studies and clinical trials are warranted to confirm potential benefits of ARBs on rates of amyloid-β accumulation in the contexts of Alzheimer's disease prevention and treatment.

Renin-Angiotensin System and Alzheimer's Disease Pathophysiology: From the Potential Interactions to Therapeutic Perspectives

New roles of the Renin-Angiotensin System (RAS), apart from fluid homeostasis and Blood Pressure (BP) regulation, are being progressively unveiled, since the discoveries of RAS alternative axes and local RAS in different tissues, including the brain. Brain RAS is reported to interact with pathophysiological mechanisms of many neurological and psychiatric diseases, including Alzheimer's Disease (AD). Even though AD is the most common cause of dementia worldwide, its pathophysiology is far from elucidated. Currently, no treatment can halt the disease course. Successive failures of amyloid-targeting drugs have challenged the amyloid hypothesis and increased the interest in the inflammatory and vascular aspects of AD. RAS compounds, both centrally and peripherally, potentially interact with neuroinflammation and cerebrovascular regulation. This narrative review discusses the AD pathophysiology and its possible interaction with RAS, looking forward to potential therapeutic approaches. RAS molecules affect BP, cerebral blood flow, neuroinflammation, and oxidative stress. Angiotensin (Ang) II, via angiotensin type 1 receptors may promote brain tissue damage, while Ang-(1-7) seems to elicit neuroprotection. Several studies dosed RAS molecules in AD patients' biological material, with heterogeneous results. The link between AD and clinical conditions related to classical RAS axis overactivation (hypertension, heart failure, and chronic kidney disease) supports the hypothesized role of this system in AD. Additionally, RAStargeting drugs as Angiotensin Converting Enzyme inhibitors (ACEis) and Angiotensin Receptor Blockers (ARBs) seem to exert beneficial effects on AD. Results of randomized controlled trials testing ACEi or ARBs in AD are awaited to elucidate whether AD-RAS interaction has implications on AD therapeutics.

Alzheimer's disease and related dementias risk: Comparing users of non-selective and M3-selective bladder antimuscarinic drugs

PURPOSE

Bladder antimuscarinic (BAM) drug use is associated with increased risk of Alzheimer's disease and related dementias (ADRD). It is hypothesized that BAMs with non-selective receptor binding may increase ADRD risk more than M3-selective BAMs. This study compared ADRD risk for users of non-selective and M3-selective BAMs and examines ADRD risk associated with overall BAM use.

METHODS

Retrospective cohort study of Medicare claims for 71 688 individuals who used BAM drugs during 2007-2009 without an ADRD diagnosis. We compared ADRD incidence (2011-2016) between non-selective BAM users (fesoterodine, flavoxate, oxybutynin, tolterodine, trospium) and M3-selective BAM users (darifenacin, solifenacin). Logistic regressions compared individuals using target drugs in the same category of total standardized daily doses (TSDD) as a standardized measure of drug exposure, and adjusted for age, sex, race/ethnicity, healthcare utilization, other medication use, socioeconomic status, and comorbidities. Secondary analyses compared ADRD risk associated with different doses of BAMs overall.

RESULTS

Non-selective BAM use (compared to M3-selective) was not significantly associated with ADRD incidence. Odds ratios for non-selective use were 0.97 (CI: 0.89-1.04) for 1-364 TSDD, 0.94 (CI: 0.83-1.06) for 365-729, 1.00 (CI: 0.87-1.16) for 730-1094, and 1.03 (CI: 0.88-1.20) for >1094. Higher TSDD of BAMs overall (combining both non-selective and M3-selective BAMs), when compared to 1-364 TSDD, were associated with increased ADRD incidence (OR = 1.05 (CI: 0.99-1.10) for 365-729, OR = 1.11 (CI: 1.05-1.17) for 730-1094, and OR = 1.10 (CI: 1.04-1.15) for >1094).

CONCLUSIONS

Non-selective and M3-selective BAM users had similar odds of ADRD incidence, and BAM use overall was significantly associated with ADRD incidence.

Increases in hypertension-induced cerebral microhemorrhages exacerbate gait dysfunction in a mouse model of Alzheimer's disease

Clinical studies show that cerebral amyloid angiopathy (CAA) associated with Alzheimer's disease (AD) and arterial hypertension are independent risk factors for cerebral microhemorrhages (CMHs). To test the hypothesis that amyloid pathology and hypertension interact to promote the development of CMHs, we induced hypertension in the Tg2576 mouse model of AD and respective controls by treatment with angiotensin II (Ang II) and the NO synthesis inhibitor L-NAME. The number, size, localization, and neurological consequences (gait alterations) of CMHs were compared. We found that compared to control mice, in TG2576 mice, the same level of hypertension led to significantly increased CMH burden and exacerbation of CMH-related gait alterations. In hypertensive TG2576 mice, CMHs were predominantly located in the cerebral cortex at the cortical-subcortical boundary, mimicking the clinical picture seen in patients with CAA. Collectively, amyloid pathologies exacerbate the effects of hypertension, promoting the genesis of CMHs, which likely contribute to their deleterious effects on cognitive function. Therapeutic strategies for prevention of CMHs that reduce blood pressure and preserve microvascular integrity are expected to exert neuroprotective effects in high-risk elderly AD patients.

Research Progress of Alzheimer's Disease Therapeutic Drugs: Based on Renin-Angiotensin System Axis

It is widely recognized that Alzheimer's disease (AD) has a complicate link to renin-angiotensin system (RAS). It is known that cerebrovascular disease has some connections with AD, but most of the studies are still conducted in parallel or independently. Although previous research came up with large number of hypotheses about the pathogenesis of AD, it does not include the mechanism of RAS-related regulation of AD. It has been found that many components of RAS have been changed in AD. For example, the multifunctional and high-efficiency vasoconstrictor Ang II and Ang III with similar effects are changed under the action of other RAS signal peptides; these signal peptides are believed to help improve nerve injury and cognitive function. These changes may lead to neuropathological changes of AD, and progressive defects of cognitive function, which are association with some hypotheses of AD. The role of RAS in AD gradually attracts our attention, and RAS deserved to be considered carefully in the pathogenesis of AD. This review discusses the mechanisms of RAS participating in the three current hypotheses of AD: neuroinflammation, oxidative stress and amyloid-β protein (Aβ) hypothesis, as well as the drugs that regulate RAS systems already in clinical or in clinical trials. It further demonstrates the importance of RAS in the pathogenesis of AD, not only because of its multiple aspects of participation, which may be accidental, but also because of the availability of RAS drugs, which can be reused as therapies of AD.

Association of Angiotensin II-Stimulating Antihypertensive Use and Dementia Risk: Post Hoc Analysis of the PreDIVA Trial

OBJECTIVE

To assess whether angiotensin II-stimulating antihypertensives (thiazides, dihydropyridine calcium channel blockers, and angiotensin I receptor blockers) convey a lower risk of incident dementia compared to angiotensin II-inhibiting antihypertensives (angiotensin-converting enzyme inhibitors, β-blockers, and nondihydropyridine calcium channel blockers), in accordance with the "angiotensin hypothesis."

METHODS

We performed Cox regression analyses of incident dementia (or mortality as competing risk) during 6-8 years of follow-up in a population sample of 1,909 community-dwelling individuals (54% women) without dementia, aged 70-78 (mean 74.5 ± 2.5) years.

RESULTS

After a median of 6.7 years of follow-up, dementia status was available for 1,870 (98%) and mortality for 1,904 (>99%) participants. Dementia incidence was 5.6% (27/480) in angiotensin II-stimulating, 8.2% (59/721) in angiotensin II-inhibiting, and 6.9% (46/669) in both antihypertensive type users. Adjusted for dementia risk factors including blood pressure and medical history, angiotensin II-stimulating antihypertensive users had a 45% lower incident dementia rate (hazard ratio [HR], 0.55; 95% CI, 0.34-0.89) without excess mortality (HR, 0.86; 95% CI, 0.64-1.16), and individuals using both types had a nonsignificant 20% lower dementia rate (HR, 0.80; 95% CI,0.53-1.20) without excess mortality (HR, 0.97; 95% CI, 0.76-1.24), compared to angiotensin II-inhibiting antihypertensive users. Results were consistent for subgroups based on diabetes and stroke history, but may be specific for individuals without a history of cardiovascular disease.

CONCLUSIONS

Users of angiotensin II-stimulating antihypertensives had lower dementia rates compared to angiotensin II-inhibiting antihypertensive users, supporting the angiotensin hypothesis. Confounding by indication must be examined further, although subanalyses suggest this did not influence results. If replicated, dementia prevention could become a compelling indication for older individuals receiving antihypertensive treatment.

Vascular contributions to cognitive impairment and dementia (VCID): A report from the 2018 National Heart, Lung, and Blood Institute and National Institute of Neurological Disorders and Stroke Workshop

Vascular contributions to cognitive impairment and dementia (VCID) are characterized by the aging neurovascular unit being confronted with and failing to cope with biological insults due to systemic and cerebral vascular disease, proteinopathy including Alzheimer's biology, metabolic disease, or immune response, resulting in cognitive decline. This report summarizes the discussion and recommendations from a working group convened by the National Heart, Lung, and Blood Institute and the National Institute of Neurological Disorders and Stroke to evaluate the state of the field in VCID research, identify research priorities, and foster collaborations. As discussed in this report, advances in understanding the biological mechanisms of VCID across the wide spectrum of pathologies, chronic systemic comorbidities, and other risk factors may lead to potential prevention and new treatment strategies to decrease the burden of dementia. Better understanding of the social determinants of health that affect risks for both vascular disease and VCID could provide insight into strategies to reduce racial and ethnic disparities in VCID.