The ACE Insertion Deletion polymorphism relates to dementia by metabolic phenotype, APOEepsilon4, and age of dementia onset

Genetic polymorphisms in the renin-angiotensin system and cognitive decline in Parkinson's disease

Background

Renin-angiotensin system (RAS) influences the central nervous system not only through its peripheral impact—the brain possesses its own local RAS. Studies showed altered RAS components in Parkinson’s disease (PD) and their association with oxidative stress which may be linked to neurodegeneration and dementia. Moreover, the protective functions of RAS blockade antagonists against cognitive decline and dementia have been suggested. This study aimed to examine whether genetic variability in RAS genes correlates with cognitive decline in PD.

Methods and results

We genotyped single nucleotide polymorphisms (SNPs) in angiotensinogen (AGT: rs699, rs4762), angiotensin II receptors (AGTR1: rs5186 and AGTR2: rs5194, rs1403543) genes, as well as insertion/deletion polymorphism in the angiotensin-converting enzyme (ACE I/D) gene in 256 PD patients, divided into three groups: without cognitive decline, with mild cognitive impairment and with PD dementia. We did not find any significant differences in the frequencies of the analysed polymorphisms in any of the groups.

Conclusions

Despite no direct correlation between the investigated polymorphisms in RAS genes and cognitive decline in PD, we believe the impact of those genotypes may be indirect, affecting RAS blockade treatment.

Supplementary Information

The online version contains supplementary material available at 10.1007/s11033-021-06569-6.

Arterial Blood Pressure Variability and Other Vascular Factors Contribution to the Cognitive Decline in Parkinson's Disease

Dementia is one of the most disabling non-motor symptoms in Parkinson’s disease (PD). Unlike in Alzheimer’s disease, the vascular pathology in PD is less documented. Due to the uncertain role of commonly investigated metabolic or vascular factors, e.g., hypertension or diabetes, other factors corresponding to PD dementia have been proposed. Associated dysautonomia and dopaminergic treatment seem to have an impact on diurnal blood pressure (BP) variability, which may presumably contribute to white matter hyperintensities (WMH) development and cognitive decline. We aim to review possible vascular and metabolic factors: Renin-angiotensin-aldosterone system, vascular endothelial growth factor (VEGF), hyperhomocysteinemia (HHcy), as well as the dopaminergic treatment, in the etiopathogenesis of PD dementia. Additionally, we focus on the role of polymorphisms within the genes for catechol-O-methyltransferase (COMT), apolipoprotein E (APOE), vascular endothelial growth factor (VEGF), and for renin-angiotensin-aldosterone system components, and their contribution to cognitive decline in PD. Determining vascular risk factors and their contribution to the cognitive impairment in PD may result in screening, as well as preventive measures.

ACE gene missense mutation in a case with early-onset, rapid progressing dementia

The population of early-onset Alzheimer’s disease (EOAD) accounts for 1%–2% of the total population of Alzheimer’s disease, and genetic mutations are more common in EOAD. The first symptom of the patient in the present case report was the decline in memories of recent events, and the disease progressed rapidly in the following 2 years. Genetic testing has revealed the presence of genetic mutations (c.A479G, p.N160S) of ACE, which causes the 160th codon of the ACE protein to change from aspartic acid to serine, and at the same time genotype of apolipoprotein E (APOE) is ɛ3/ɛ4. We think that this patient carries the mutation type of the sensitive gene ACE and the risk gene APOE of Alzheimer’s disease, and this is the reason why the disease progressed rapidly. Moreover, we discussed ACE genetic mutation’s meaning in EOAD progression.

Increased Risk of Dementia in Subjective Cognitive Decline if CT Brain Changes are Present

Background:

Subjective cognitive decline (SCD) has low predictive value for incident dementia.

Objectives:

We examined whether CT detectable brain changes add predictive value to SCD in a population sample with high scores on the Mini-Mental State Examination.

Methods:

Subjective reports of memory and executive function were gathered in a non-demented population sample ≥70 years (n = 921). CT-brain was performed at baseline (n = 626). Brain atrophy, infarcts, and white matter lesions (WMLs) were classified using visual ratings. Dementia incidence was evaluated periodically during 12 years.

Results:

The prevalence of SCD was 32.5% among individuals without dementia. During follow-up, 151 individuals (16.4%) developed dementia. The risk of dementia was increased in SCD, and increased further with WMLs and cortical atrophy present. However, the positive predictive values for incident dementia were low, 25% in SCD and 41% in SCD with WMLs and cortical atrophy.

Conclusion:

Our observations add clinical value to the use of SCD and CT to select relevant populations for interventions against dementia, but more stringent screening methods are necessary to reach individuals at risk.

Atrial fibrillation increases the risk of dementia amongst older adults even in the absence of stroke

BACKGROUND

Atrial fibrillation increases risk of stroke, and thus risk of cognitive impairment and dementia. Emerging evidence suggests an association also in the absence of stroke. We aimed to examine the association between atrial fibrillation and incident dementia, with and without exclusion of individuals with stroke, and if sex and genetic factors modify the possible association.

METHODS

In 2000-2001, a population-based sample of 70-year-olds (N = 561) underwent comprehensive somatic and neuropsychiatric examinations, as part of the Gothenburg H70 Birth Cohort Studies. Participants were followed up at age 75 and 79. Atrial fibrillation at baseline was identified through ECG, proxy-reports and the National Patient Register (NPR). Stroke at baseline and follow-up was identified through self-reports, proxy-reports and the NPR. Dementia at baseline and follow-up was diagnosed according to the DSM-III-R criteria based on neuropsychiatric examinations, proxy-reports and the NPR.

RESULTS

Individuals with atrial fibrillation had an almost threefold increased risk of dementia during 12-year follow-up (HR 2.8; 95% CI 1.3-5.7; P = 0.004), and this risk remained after excluding individuals with stroke at baseline and follow-up. After stratification for sex, the association was only found amongst men (HR 4.6; 95% CI 1.9-11.2; P < 0.001, interaction sex*atrial fibrillation; P = 0.047) and noncarriers of the APOE ε4 allele (HR 4.2; 95% CI 1.8-9.7; P < 0.001, interaction APOE*atrial fibrillation; P = 0.128). Population attributable risk for dementia resulting from atrial fibrillation was 13%.

CONCLUSION

The relevance for atrial fibrillation as an indicator of subclinical brain vascular risk needs to be further explored. In addition, patients with atrial fibrillation should be screened for cognitive symptoms.

The ACE Gene Is Associated with Late-Life Major Depression and Age at Dementia Onset in a Population-Based Cohort

OBJECTIVE

Depression and dementia in the elderly have been suggested to share similar risk factors and pathogenetic background, and recently the authors reported that the APOEɛ4 allele is a risk factor for both disorders in the general population. The aim of the present study was to examine the influence of the well-known polymorphisms rs1799752 in the angiotensin-converting enzyme (ACE) and rs5186 in the angiotensin receptor II type 1 (AGTR1) on late-life depression and dementia in a population-based Swedish cohort of older individuals followed over 12 years.

METHODS

In 2000-2001, 900 individuals underwent neuropsychiatric and neuropsychological examinations. Follow-up evaluations were performed in 2005-2006 and 2009-2010, and register data on dementia to 2012 were included. Cross-sectional associations between genotypes/alleles and depression and dementia at baseline and between genotypes/alleles and depression on at least one occasion during the study period and dementia onset to 2012 were investigated.

RESULTS

As previously found for rs1799752 in ACE, rs5186 in AGTR1 was associated with dementia at baseline (OR: 3.25 [CI: 1.42-7.06], z = 2.90, p = 0.004). These associations became substantially weaker, or disappeared, when dementia onset to 2012 was included. For rs1799752 this could be explained by a significant association with age at onset (mean: 79.5 [SD: 6.45] years for risk-genotype carriers and 81.7 [SD: 7.12] years for carriers of other genotypes, b = -2.43, t = -2.38, df = 192, p = 0.02). When individuals with major depression on at least one occasion were analyzed, a significant association (OR: 2.14 [95% CI: 1.13-4.20], z = 2.28, p = 0.02), remaining after exclusion of dementia, with rs1799752 in ACE was found.

CONCLUSION

In this population-based sample of older individuals, genetic variations in ACE seem to be important both for late-life major depression and dementia.

Antihypertensive Therapies and Cognitive Function: a Review

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

Cholesterol in mild cognitive impairment and Alzheimer's disease in a birth cohort over 14 years

Animal epidemiological and clinical studies suggest that cholesterol is a risk factor for Alzheimer's disease (AD). Nevertheless, the relation of cholesterol to mild cognitive impairment (MCI), influence of APOE genotype and its changes in lifespan is controversial. We investigated the potential impact of plasma total cholesterol (TC) on development of MCI and AD in the interdisciplinary longitudinal study on adult development and aging, a representative birth cohort (born 1930-1932), examined in 1993/1994 (VT1), 1997/1998 (VT2), and 2005/2007 (VT3). Of 500 participants at baseline, 381 survived and were examined at VT3. After exclusion of participants with lifetime prevalence of major psychiatric diseases or mild cognitive disorder due to a medical condition, 222 participants were included in the analysis. At VT3, 82 participants had MCI, 22 participants had AD, and 118 were in good health. Participants with MCI and AD at VT3 evidenced higher TC levels at VT1 than those who were healthy. Higher TC levels at baseline were associated with an increased risk for cognitive disorders at VT3 (highest vs. lowest quartile: OR 2.64, 95 % CI 1.12-6.23, p < 0.05). Over the 14 year follow-up, TC levels declined in those with MCI and AD, but remained stable in those who remained healthy. These findings were not modified by APOE genotype or use of cholesterol-lowering medications. Our findings demonstrate that higher TC levels are observed long before the clinical manifestation of MCI and AD in patients without psychiatric or somatic comorbidities and are independent of APOE genotype.

Hypertension, brain damage and cognitive decline

Loss of cognitive function is one the most devastating manifestations of ageing and vascular disease. Cognitive decline is rapidly becoming an important cause of disability worldwide and contributes significantly to increased mortality. There is growing evidence that hypertension is the most important modifiable vascular risk factor for development and progression of both cognitive decline and dementia. High blood pressure contributes to cerebral small and large vessel disease resulting in brain damage and dementia. A decline in cerebrovascular reserve capacity and emerging degenerative vascular wall changes underlie complete and incomplete brain infarcts, haemorrhages and white matter hyperintensities. This review discusses the complexity of factors linking hypertension to brain functional and structural changes, and to cognitive decline and dementia. The evidence for possible clinical markers useful for prevention of decreased cognitive ability, as well as recent data on vascular mechanism in the pathogenesis of cognitive decline, and the role of antihypertensive therapies in long-term prevention of late-life cognitive decline will be reviewed.

ACE polymorphism and use of ACE inhibitors: effects on memory performance

Memory is an important cognition function, being fundamental to the development and independence of individuals. Our aim was to investigate the influence apolipoprotein E (APOE) and angiotensin I-converting enzyme (ACE) polymorphism and ACE inhibitors use, besides their interaction on memory performance of healthy subjects over 50 years. The sample consisted of 205 subjects assessed for five types of episodic memory, using Wechsler Memory Scale-Revised (WMS-R), who answered a questionnaire about drug use and were assessed for the ACE insertion/deletion polymorphism and APOE polymorphism. We found no influence of the APOE gene. The use of ACE inhibitors beneficially influenced learning ability scores (p = 0.02). Besides, I allele carriers of ACE polymorphism showed higher verbal memory scores compared with homozygous DD. Also, we observed an interaction influencing learning ability between the ACE polymorphism and the use of inhibitors, the beneficial influence of the I allele was present only in individuals who make use of ACE inhibitors. We conclude that the ACE gene has influence on memory performance, and that this influence is modulated by ACE inhibitors use.

Personality factors moderate the associations between apolipoprotein genotype and cognitive function as well as late onset Alzheimer disease

OBJECTIVES

We tested the hypothesis that neuroticism moderates the association between APOE (apolipoprotein E) genotype and two major outcomes, cognitive function and Alzheimer disease. We also explored whether other personality dimensions (extraversion, openness to experience, agreeableness, and conscientiousness) moderate the associations of APOE with these outcomes.

DESIGN

Primary analyses of existing randomized clinical trial data.

SAMPLE

Six-hundred two older adults (mean age of 78 years at baseline).

MEASUREMENTS

APOE genotype, the NEO-Five Factor Inventory, the Alzheimer's Disease Assessment Scale-Cognitive: measured every 6 months for 6.5 years) and relevant covariates.

RESULTS

Fully adjusted multivariate analyses showed that the association between the presence of APOE [Latin Small Letter Open E]-4 allele(s) and both outcomes was evident among individuals with high levels of neuroticism and extraversion but not among persons with low levels of these traits.

CONCLUSIONS

Phenotypic personality dimensions, primarily neuroticism and extraversion, moderate the relationship between APOE [Latin Small Letter Open E]-4 genotype and cognitive outcomes among older adults. Future research is needed to elucidate the physiological processes involved in these particular phenotype-genotype interactions.

Gene by neuroticism interaction and cognitive function among older adults

OBJECTIVES

Both apolipoprotein E (ApoE) ε-4 allele(s) and elevated trait neuroticism, the tendency to experience distress, are associated with cognitive function among older adults. We predicted that neuroticism moderates the association between ApoE and cognitive function and also explored whether other personality dimensions (openness to experience, agreeableness, extraversion, and conscientiousness) affect the association between ApoE status and cognitive function.

METHOD

Five-hundred and ninety-seven older adults (mean age of 78 years) enrolled in the Ginkgo Evaluation of Memory study completed the NEO five-factor inventory of personality. Cognitive function was assessed via the cognitive portion of the Alzheimer's Disease Assessment Scale, and a blood sample for ApoE genotyping was drawn.

RESULTS

As hypothesized, regression analysis indicated that neuroticism moderated the relationship between the presence of ApoE ε-4 and cognitive function. Individuals with high neuroticism scores had significantly lower scores on the cognitive portion of the Alzheimer's Disease Assessment Scale compared with individuals with low neuroticism scores, but this was true only among carriers of ApoE ε-4 (interaction effect β = 0.124, p = 0.028). There was scant evidence that other personality dimensions moderate the association between ApoE ε-4 and cognitive function.

CONCLUSIONS

Cognitive function may be affected by ApoE and neuroticism acting in tandem. Research on the underlying physiological mechanisms by which neuroticism amplifies the effect of ApoE ε-4 is warranted. The study of genotype by phenotype interactions provides an important and useful direction for the study of cognitive function among older adults and for the development of novel prevention programs.

The genetic architecture of Alzheimer's disease: beyond APP, PSENs and APOE

Alzheimer's disease (AD) is a complex disorder with a clear genetic component. Three genes have been identified as the cause of early onset familial AD (EOAD). The most common form of the disease, late onset Alzheimer's disease (LOAD), is, however, a sporadic one presenting itself in later stages of life. The genetic component of this late onset form of AD has been the target of a large number of studies, because only one genetic risk factor (APOE4) has been consistently associated with the disease. However, technological advances allow new approaches in the study of complex disorders. In this review, we discuss the new results produced by genome wide association studies, in light of the current knowledge of the complexity of AD genetics.