A high incidence of apolipoprotein E ε4 allele in middle-aged non-demented subjects with cerebral amyloid β protein deposits

We examined the apolipoprotein E (ApoE) genotypes of 19 middle-aged non-demented subjects with cerebral amyloid β protein (Aβ) deposits, and compared the results with those of 16 patients with sporadic Alzheimer’s disease (AD) and those of 34 age-matched controls. The frequency of the ApoE ɛ4 allele was higher (P = 0.0256) in these 19 subjects (0.211) than in controls (0.059), and was close to that in AD patients (0.281). This result suggests that middle-aged non-demented subjects with cerebral Aβ deposits are at high risk of developing AD, and that the diffuse Aβ deposits in these cases represent an early stage of AD pathology. We speculate that in the majority of late-onset sporadic AD patients, cerebral Aβ deposition commences when these patients are in their forties or fifties, and that the pathological process progresses gradually, taking 20 to 30 years for clinical manifestation of dementia. Received: 16 March 1998 / Revised, accepted: 29 June 1998     

Lack of association between schizophrenia and the apolipoprotein E ε4 allele

The association between the 4 allele of the apolipoprotein E (APOE) gene and Alzheimer's disease (AD) has been reported. In order to examine if the 4 allele may play a role also in schizophrenia, another mental disorder, patients (n=87) and control subjects (n=57) were genotyped for APOE. No significant difference was found between the groups. The data indicate that the APOE gene is not of major importance for the genesis of schizophrenia.     

Decreased brain creatine levels in elderly apolipoprotein E ε4 carriers

Summary. Apolipoprotein E (ApoE) genotype has been shown to influence results in neuroimaging studies using a number of various imaging modalities. No in vivo data exists on whether or not there are ApoE-related changes observable by proton magnetic resonance spectroscopy (MRS). In this study we measured absolute peak areas of proton MR spectra obtained from the occipital cortex in 22 non-demented elderly with (n = 8) or without (n = 14) the ApoE ε4 allele. No statistically significant differences were found in levels of N-acetyl aspartate, myo-inositol, or choline containing compounds between the groups. Instead, compared with the non-carriers, the levels of creatine were significantly lower in the ε4 carriers, suggesting increased metabolic demands in the brain of the ε4 carriers. The levels of creatine also correlated significantly with age and performance on the Mini-Mental State Examination test in the ε4 carriers, but not in the non-carriers. These findings may be of significant clinical interest as potential indicator of incipient AD, and also from therapeutical point of view given the potential neuroprotective effects of creatine. Received February 18, 2002; accepted August 5, 2002 Published online December 9, 2002 Acknowledgements This study was supported by the Research Council for Health of the Academy of Finland, the Finnish Neurology Foundation, the Instrumentarium Research Foundation, and the Farmos Research Foundation. Authors' address: M. Laakso, Department of Neurology, Bldg. 5, Kuopio University Hospital, P.O.Box 1777, 70211 Kuopio, Finland, e-mail: mikko.laakso@uku.fi Abbreviations AD Alzheimer's disease, ApoE apolipoprotein E, MI myo-inositol, MMSE Mini-Mental State Examination, MRI magnetic resonance imaging, MRS magnetic resonance spectroscopy, NAA N-acetyl aspartate.     

Impact of the apolipoprotein E ε4 allele on early Parkinson's disease progression

ObjectiveEmerging evidence shows that apolipoprotein E (APOE) ε4 exacerbates alpha-synuclein pathology. We aimed to investigate whether the APOE ε4 allele contributes to early Parkinson's disease (PD) progression.MethodsThis cohort study included 361 early PD patients who were classified as APOE ε4 carriers (n = 90) and noncarriers (n = 271). The patients underwent yearly motor and nonmotor assessments covering neuropsychiatric, sleep-related, and autonomic symptoms over 5 years of follow-up. Dopamine transporter (DAT) imaging was conducted at baseline and the 1-, 2-, and 4-year follow-up visits.ResultsThe APOE ε4 carriers had steeper declines in the Montreal Cognitive Assessment score (p=0.005) and the semantic fluency test score (p=0.012) than the noncarriers. No significant between-group differences in the longitudinal changes in motor, other nonmotor, and DAT imaging variables were observed.ConclusionsOur exploratory analyses show that only cognitive performance was negatively affected by the APOE ε4 allele in the progression of early PD. More specifically, this allele was associated with poorer performance in semantic verbal fluency among cognitive domains.     

Adiposity measures predict olfactory processing speed in older adult carriers of the apolipoprotein E ε4 allele

ObjectiveThe current study investigated the relationship between adiposity and P3 latency.MethodsFifty-one adults in two age groups (18–25 and 65+) participated. Odor stimuli were delivered via olfactometer as participants focused on a computer screen. Each stimulus was followed by presentation on the screen of four odor identification choices. Participants attempted identification by button press. Olfactory event-related potentials (OERPs) were recorded. BMI and waist circumference were measured as indicators of adiposity.ResultsIn bivariate analyses with all participants included, positive correlations for P3 latency with both BMI and waist circumference were observed, indicating that as adiposity increased latencies also increased. When each age group was separately examined, correlations between adiposity measures and latency remained statistically significant for older adults. Furthermore, ApoE ε4 allele status was examined. Latencies remained positively correlated with adiposity in older adult ε4 carriers; but not in non-carriers.ConclusionsThis study indicates that adiposity predicts olfactory processing speed in older adults, specifically in ε4 carriers.SignificanceThe results suggest that olfactory processing speed may be a useful measure for detecting and following the effects of adiposity on brain integrity and cognitive function in those at genetic risk for AD.     

APOE ε4 influences β-amyloid deposition in primary progressive aphasia and speech apraxia

BackgroundApolipoprotein E ε4 (APOE ε4) is a risk factor for β-amyloid deposition in Alzheimer's disease dementia. Its influence on β-amyloid deposition in speech and language disorders, including primary progressive aphasia (PPA), is unclear.MethodsOne hundred thirty subjects with PPA or progressive speech apraxia underwent APOE genotyping and Pittsburgh compound B (PiB) PET scanning. The relationship between APOE ε4 and PiB status, as well as severity and regional distribution of PiB, was assessed.ResultsForty-five subjects had an APOE ε4 allele and 60 subjects were PiB-positive. The odds ratio for a subject with APOE ε4 being PiB-positive compared with a subject without APOE ε4 being PiB-positive was 10.2 (95% confidence interval, 4.4–25.5; P < .0001). The APOE ε4 allele did not influence regional PiB distribution or severity.ConclusionAPOE ε4 increases the risk of β-amyloid deposition in PPA and progressive speech apraxia but does not influence regional β-amyloid distribution or severity.     

Prevalence of the apolipoprotein E ε4 allele in amyloid β positive subjects across the spectrum of Alzheimer's disease

Introduction

Apolipoprotein E (APOE) ε4 is the major genetic risk factor for Alzheimer's disease (AD), but its prevalence is unclear because earlier studies did not require biomarker evidence of amyloid β (Aβ) pathology.

Presence of apolipoprotein E on extracellular neurofibrillary tangles and on meningeal blood vessels precedes the Alzheimer β-amyloid deposition

The localization of apolipoprotein E (ApoE) has been examined immunohistochemically in the autopsied brains of middle-aged and old-aged control subjects, with and without amyloid protein (A) deposits, and of Alzheimer's disease patients. Senile plaques were consistently labeled with ApoE antiserum even in the very early stage of senile plaque formation seen in the fifth decade. In the cerebellar molecular layer, small dots of ApoE immunoreactivity, which were prominent in the Alzheimer's disease subjects, were observed in addition to immunoreactivity in diffuse plaques. ApoE antisera labeled all of the extracellular neurofibrillary tangles (NFT), whereas only a small minority of extracellular NFT were positive for A. A punctate pattern of ApoE immunoreactivity was seen at the media of the meningeal vessels lacking amyloid, when senile plaques were present in the nearby cortex. In the early stage of amyloid angiopathy, the distribution of ApoE immunoreactivity was much more extensive than that of A positivity. These findings suggest that ApoE accumulates in the early stage of senile plaque formation and, furthermore, that ApoE accumulation precedes A deposition in extracellular NFT and amyloid angiopathy.     

Association of apolipoprotein E ε4 allele with cognitive impairment in patients with epilepsy and interaction with phenytoin monotherapy

Cognitive impairment implicates many factors beyond phenytoin monotherapy in patients with epilepsy. Apolipoprotein E ε4 allele has been reported to play a role in severe memory impairment that ultimately progresses to Alzheimer's disease (AD); however, knowledge about its role in cognitive impairment in patients with epilepsy is lacking. Our study proposes the possible involvement of the APOE ε4 allele in cognitive impairment in patients with epilepsy which is further worsened by phenytoin monotherapy. Assessment of the APOE ε4 allele in a population with epilepsy will help to identify the patients vulnerable to cognitive impairment and, therefore, the corrective therapy that needs to be addressed.     

The insertion polymorphism in angiotensin-converting enzyme gene associated with the APOE ε4 allele increases the risk of late-onset Alzheimer disease

Several studies have shown that a common insertion (I)/deletion (D) polymorphism of angiotensin-converting enzyme (ACE) gene may confer an increased risk of late-onset Alzheimer disease (LOAD). However, the result has not been replicated by all studies. In order to clarify the role of the polymorphism for the occurrence of LOAD in Chinese and the possibility of a synergistic effect with the apolipoprotein E allele 4 on the risk of Alzheimer disease, we examined the ACE and APOE genotypes in a Chinese sample consisting of 104 sporadic LOAD patients and 128 healthy controls. An obvious difference of allelic and genotypic distributions of ACE I/D polymorphism between cases and controls was observed (chi2 = 6.61, df = 2, p = 0.037 by genotype; chi2 = 4.67, df = 1, p = 0.031 by allele). And ACE I allele carriers showed an increased risk for LOAD developing (chi2 = 6.59, df = 1, p =0.01, OR = 2.91, 95% CI 1.25-6.77). After stratifying by APOE epsilon 4 status, the increased LOAD risks associated with I allele carriers only in the APOE epsilon 4 noncarriers was seen (chi2 = 4.12, df = 1, p = 0.042). Logistic regression analysis of total subjects demonstrated a more than sevenfold increase in the risk of developing LOAD in subjects carrying both the ACE I allele and the APOE epsilon 4 (OR = 7.39, 95% CI 2.50-21.89, p < 0.001). Our data revealed that ACE I/D polymorphism is considered to be an additional risk factor, which has strong synergistic interaction with APOE epsilon 4 on the risk of LOAD.     

Physical activity modifies the influence of apolipoprotein E ε4 allele and type 2 diabetes on dementia and cognitive impairment among older Mexican Americans

Introduction

The etiologies of dementia are complex and influenced by genetic and environmental factors including medical conditions.

Apolipoprotein E4 promotes the early deposition of Aβ42 and then Aβ40 in the elderly

The apolipoprotein Eɛ4 allele (ApoEɛ4) is associated with a selective increase in deposition of the 40-amino acid form of the β-amyloid peptide (Aβ40) in end-stage Alzheimer’s disease. To determine how apoE genotype affects the early events in β-amyloid pathogenesis, we analyzed the medial temporal lobes of 244 elderly persons who were not clinically demented using antibodies selective for the C termini of Aβ40 and Aβ42. We found that: (1) the number of both Aβ42- and Aβ40-positive senile plaques increase with age; (2) Aβ42 appears at younger ages, and in more amyloid deposits, than does Aβ40 in all ApoE groups; (3) when compared at similar ages, older persons with ApoEɛ4 are more likely to have Aβ42- and Aβ40-immunoreactive deposits than are persons without ApoEɛ4; (4) Aβ40-containing plaques arise at least a decade later than do Aβ42 plaques, and are seldom found in the medial temporal lobe of older persons lacking ApoEɛ4; and (5) in the absence of overt Alzheimer’s disease, cerebral amyloid angiopathy is rare in the elderly, but in our sample was significantly augmented in ApoEɛ4 homozygotes. We conclude that ApoEɛ4 hastens the onset of Aβ42 deposition in the senescent brain, which in turn fosters the earlier evolution of fibrillar, Aβ40-positive plaques, thereby increasing the risk of Alzheimer’s disease. Received: 18 June 1999 / Revised: 8 October 1999 / Accepted: 12 October 1999     

Apolipoprotein E ε4 genotype status is not associated with neuroimaging outcomes in a large cohort of HIV+ individuals

Previous neuroimaging studies suggest a negative relationship between the apolipoprotein (ApoE) ε4 allele and brain integrity in human immunodeficiency virus (HIV)-infected (HIV+) individuals, although the presence of this relationship across adulthood remains unclear. The purpose of this study is to clarify the discrepancies using a large, diverse group of HIV+ individuals and multiple imaging modalities sensitive to HIV. The association of ApoE ε4 with structural neuroimaging and magnetic resonance spectroscopy (MRS) was examined in 237 HIV+ individuals in the CNS HIV Anti-Retroviral Therapy Effects Research (CHARTER) study. Cortical and subcortical gray matter, abnormal and total white matter, ventricles, sulcal cerebrospinal fluid (CSF), and cerebellar gray matter, white matter, and CSF volumes, and MRS concentrations of myo-inositol, creatine, N-acetyl-aspartate, and choline in the frontal white matter (FWM), frontal gray matter (FGM), and basal ganglia were examined. Secondary analyses explored this relationship separately in individuals ≥50 years old (n?=?173) and <50 years old (n?=?63). No significant differences were observed between ApoE ε4+ (ApoE ε3/ε4 and ApoE ε4/ε4) individuals (n?=?69) and ApoE ε4? (ApoE ε2/ε3 and ApoE ε3/ε3) individuals (n?=?167). When individuals were further divided by age, no significant genotype group differences were identified in individuals <50 or ≥50 years of age on any neuroimaging outcome. The ApoE ε4 allele did not affect brain integrity in this large, diverse sample of HIV+ individuals. The effects of ApoE ε4 may not be apparent until more advanced ages and may be more prominent when present along with other risk factors for neuronal damage.     

Amyloid-β 1-42 levels are modified by apolipoprotein E ε4 in Creutzfeldt-Jakob disease in a similar manner as in Alzheimer's disease

The presence of apolipoprotein E (ApoE) ε4 allele is a risk factor for Alzheimer's disease (AD) and associated with a more pronounced reduction of amyloid-β 1-42 (Aβ1-42) in the cerebrospinal fluid (CSF). Because a decrease of Aβ1-42 and increase of tau protein levels, both important biomarkers for AD, are also reported in Creutzfeldt-Jakob disease (CJD), we analyzed if a similar relationship can be observed in this rapid progressive dementia. Our study included 309 patients with sporadic CJD (147 neuropathologically confirmed and 162 probable cases). We analyzed the role of ApoE ε4 in sporadic CJD (sCJD), in particular the influence on the CSF-markers 14-3-3 protein, tau protein, neuron-specific enolase, S100 protein, Aβ1-42, and Aβ1-40. No differences in the ApoE ε4 allele frequency and ApoE genotype distribution between sCJD and published healthy controls were observed. The ApoE ε4 allele had no effect on disease duration or age at onset. We detected a dose-dependent ApoE ε4 effect on the decrease of Aβ1-42 in sCJD. ApoE ε4 carriers with one ApoE ε4 allele showed significantly reduced Aβ1-42 values (p < 0.0001) in comparison with non-carriers. ApoE ε4 allele is not a risk factor for sCJD but modifies the Aβ1-42 levels in CSF in a similar manner as in AD. Based on our results in sCJD patients, we hypothesize that the ApoE ε4 effect on Aβ1-42 values might not be disease-specific.     

Cognitive function correlations with apolipoprotein Eε4 single nucleotide polymorphism in 1 000 elderly patients following general anesthesia A randomized controlled study

BACKGROUND: Cognitive dysfunction occurs in elderly patients following general anesthesia, and this might be associated with genetics. Studies have shown that theε4 allele gene is closely associated with senile dementia.OBJECTIVE: To compare and analyze the correlations between cognitive dysfunction and single nucleotide polymorphism of apolipoprotein E (ApoE) following inhaJation or intravenous anesthesia.DESIGN, TIME AND SETTING: A randomized, controlled study was performed. The patients were recruited from the Department of Anesthesia, Second Affiliated Hospital, Medical College, Xi'an Jiaotong University, China between May 2005 and December 2008. Genetic analyses were conducted at the Departments of Neuroanatomy and Forensic Medicine, Medical College, Xi'an Jiaotong University, China.PARTICIPANTS: A total of 1 000 patients of ASA Ⅰ-Ⅱ grade, without genetic connection, were enrolled in this study, comprising 520 males and 480 females, aged (70.1±4.6) years and weighing (57.3±7.5) kg. No patients suffered from cognitive dysfunction.METHODS: The patients were equally and randomly divided into intravenous anesthesia and gas anesthesia groups. Total intravenous anesthesia and inhaled anesthesia were used. Genomic DNA from whole blood was extracted. The ApoE gene was amplified by PCR. Restriction fragment length polymorphism of ApoE gene was analyzed. Cognitive function was evaluated by Mini-Mental State Examination (MMSE). Patients scoring < 25 points were diagnosed with cognitive dysfunction.MAIN OUTCOME MEASURES: Correlation of ApoE gene frequency and ApoEε4 allele to MMSE scores was measured.RESULTS: MMSE scores in patients from the gas anesthesia group significantly decreased 3 days after surgery, compared with the intravenous anesthesia group. The proportion of patients that scored < 25 points was significantly greater in the gas anesthesia group compared with the intravenous anesthesia group 3 days after surgery. Reduced MMSE scores closely correlated with expression of the ApoEε4 allele in the gas anesthesia group (odds ratio=2.83; 95% confidence interval was 1.25-6.39, P<0.05). However, decreased MMSE scores did not closely correlated with expression of the ApoEε4 allele in the intravenous anesthesia group (odds ratio=0.96; 95% confidence interval was 0.37-2.39, P>0.05).CONCLUSION: Results demonstrated a correlation between cognitive dysfunction and ApoE single nucleotide polymorphism in elderly patients after gas anesthesia. However, no relationship between cognitive dysfunction and ApoE single nucleotide polymorphism was determined in elderly patients following intravenous anesthesia. Therefore, elderly patients, especially those expressing the ApoEε4 gene, should be cautiously exposed to gas anesthesia.     

Reduction of β-amyloid deposits by γ-secretase inhibitor is associated with the attenuation of secondary damage in the ipsilateral thalamus and sensory functional improvement after focal cortical infarction in hypertensive rats

Abnormal β-amyloid (Aβ) deposits in the thalamus have been reported after cerebral cortical infarction. In this study, we investigated the association of Aβ deposits, with the secondary thalamic damage after focal cortical infarction in rats. Thirty-six stroke-prone renovascular hypertensive rats were subjected to distal middle cerebral artery occlusion (MCAO) and then randomly divided into MCAO, vehicle, and N-[N-(3,5-difluorophenacetyl)--alanyl]-S-phenylglycine t-butyl ester (DAPT) groups and 12 sham-operated rats as control. The DAPT was administered orally at 72 hours after MCAO. Seven days after MCAO, sensory function, neuron loss, and glial activation and proliferation were evaluated using adhesive removal test, Nissl staining, and immunostaining, respectively. Thalamic Aβ accumulation was evaluated using immunostaining and enzyme-linked immunosorbent assay (ELISA). Compared with vehicle group, the ipsilateral thalamic Aβ, neuronal loss, glial activation and proliferation, and the mean time to remove the stimulus from right forepaw significantly decreased in DAPT group. The mean time to remove the stimulus from the right forepaw and thalamic Aβ burden were both negatively correlated with the number of thalamic neurons. These findings suggest that Aβ deposits are associated with the secondary thalamic damage. Reduction of thalamic Aβ by γ-secretase inhibitor may attenuate the secondary damage and improve sensory function after cerebral cortical infarction.