Apolipoprotein E polymorphism in patients with Alzheimer's disease, vascular dementia and ischemic cerebrovascular disease

Genetic Susceptibility Variants of Vascular Dementia among Asians: A Systematic Review and Meta-Analysis

INTRODUCTION

Vascular dementia (VaD), a neurocognitive impairment directly related to vascular injury, is the second most common cause of age-related dementia. Although numerous studies have investigated candidate genetic polymorphisms associated with VaD in Asia, the genetics of VaD remains unclear.

METHODS

This review provides an updated meta-analysis of genetic polymorphisms associated with VaD in Asians, using the PRISMA guidelines. Published literature up to May 2021 was extracted from the PubMed, Scopus, Ovid, and EBSCOhost databases. Meta-analysis was conducted using the Open Meta analyst, Review Manager, and MedCalc® Statistical Software. Trial sequential analysis (TSA) was performed using TSA viewer software.

RESULTS

A total of 46 eligible studies, comprising 23 genes and 35 single nucleotide polymorphisms, were retrieved. The meta-analysis was conducted on the following genetic polymorphisms, APOE ε2/3/4, MTHFR rs1801131, ACE rs4340 (I/D) gene polymorphism, and a PSEN1 intron 8 variant. The pooled odds ratio (ORs) revealed a significant increase in the risk of VaD in the apolipoprotein E (APOE) ε4 allelic model (OR, 1.79, p < 0.001), and the methylenetetrahydrofolate reductase (MTHFR) rs1801133 polymorphism T allele in the allelic model (OR, 1.23, p = 0.013).

CONCLUSION

Our findings provide evidence that genetic polymorphisms of the APOE ε4 allele and MTHFR rs1801133 T allele increase the risk of developing VaD in Asians. However, future large-scale investigations examining particularly on South-Eastern and West-Asian populations are highly recommended.

Alzheimer’s Disease: An Update and Insights Into Pathophysiology

Alzheimer’s disease (AD) is an irreversible brain disorder associated with slow, progressive loss of brain functions mostly in older people. The disease processes start years before the symptoms are manifested at which point most therapies may not be as effective. In the hippocampus, the key proteins involved in the JAK2/STAT3 signaling pathway, such as p-JAK2-Tyr1007 and p-STAT3-Tyr705 were found to be elevated in various models of AD. In addition to neurons, glial cells such as astrocytes also play a crucial role in the progression of AD. Without having a significant effect on tau and amyloid pathologies, the JAK2/STAT3 pathway in reactive astrocytes exhibits a behavioral impact in the experimental models of AD. Cholinergic atrophy in AD has been traced to a trophic failure in the NGF metabolic pathway, which is essential for the survival and maintenance of basal forebrain cholinergic neurons (BFCN). In AD, there is an alteration in the conversion of the proNGF to mature NGF (mNGF), in addition to an increase in degradation of the biologically active mNGF. Thus, the application of exogenous mNGF in experimental studies was shown to improve the recovery of atrophic BFCN. Furthermore, it is now coming to light that the FGF7/FGFR2/PI3K/Akt signaling pathway mediated by microRNA-107 is also involved in AD pathogenesis. Vascular dysfunction has long been associated with cognitive decline and increased risk of AD. Vascular risk factors are associated with higher tau and cerebral beta-amyloid (Aβ) burden, while synergistically acting with Aβ to induce cognitive decline. The apolipoprotein E4 polymorphism is not just one of the vascular risk factors, but also the most prevalent genetic risk factor of AD. More recently, the research focus on AD shifted toward metabolisms of various neurotransmitters, major and minor nutrients, thus giving rise to metabolomics, the most important “omics” tool for the diagnosis and prognosis of neurodegenerative diseases based on an individual’s metabolome. This review will therefore proffer a better understanding of novel signaling pathways associated with neural and glial mechanisms involved in AD, elaborate potential links between vascular dysfunction and AD, and recent developments in “omics”-based biomarkers in AD.

Apolipoprotein E ε4 Polymorphism as a Risk Factor for Ischemic Stroke: A Systematic Review and Meta-Analysis

Introduction

Rising studies indicate that the apolipoprotein E (APOE) gene is related to the susceptibility of ischemic stroke (IS). However, certain consensus is limited by the lack of a large sample size of researches. This meta-analysis was performed to explore the potential association between the APOE gene and IS.

Methods

To identify relevant case control studies in English publications by October 2020, we searched PubMed, Embase, Web of Science, and the Cochrane Library. Pooled odds ratios (ORs) with fixed- or random-effect models and corresponding 95% confidence intervals (CIs) were calculated to analyze potential associations.

Results

A total of 55 researches from 32 countries containing 12207 IS cases and 27742 controls were included. The association between APOE gene ε4 mutation and IS was confirmed (ε4 vs. ε3 allele: pooled OR = 1.374, 95% CI, 1.214-1.556; ε2/ε4 vs. ε3/ε3: pooled OR = 1.233, 95% CI, 1.056-1.440; ε3/ε4 vs. ε3/ε3: pooled OR = 1.340, 95% CI, 1.165-1.542; ε4/ε4 vs. ε3/ε3: pooled OR = 1.833, 95% CI, 1.542-2.179; and APOE ε4 carriers vs. non-ε4 carriers: pooled OR = 1.377; 95% CI, 1.203-1.576). Interestingly, APOE ε4 mutation showed a dose-response correlation with IS risk (ε4/ε4 vs. ε2/ε4: pooled OR = 1.625; 95% CI, 1.281-2.060; ε4/ε4 vs. ε3/ε4: pooled OR = 1.301; 95% CI, 1.077-1.571). Similar conclusions were drawn in the small artery disease (SAD) subtype, but not in large artery atherosclerosis (LAA) or in cardioaortic embolism (CE), by subgroup analysis.

Conclusions

These observations reveal that specific APOE ε4 mutation was significantly associated with the risk of IS in a dose-dependent manner, while APOE ε4 mutation was related to SAD subtype onset without a cumulative effect.

Vascular Risk Factors and Alzheimer's Disease: Blood-Brain Barrier Disruption, Metabolic Syndromes, and Molecular Links

Alzheimer's disease (AD) is a neurodegenerative disorder, marked by cortical and hippocampal deposition of amyloid-β (Aβ) plaques and neurofibrillary tangles and cognitive impairment. Studies indicate a prominent link between cerebrovascular abnormalities and the onset and progression of AD, where blood-brain barrier (BBB) dysfunction and metabolic disorders play key risk factors. Pericyte degeneration, endothelial cell damage, astrocyte depolarization, diminished tight junction integrity, and basement membrane disarray trigger BBB damage. Subsequently, the altered expression of low-density lipoprotein receptor-related protein 1 and receptor for advanced glycation end products at the microvascular endothelial cells dysregulate Aβ transport across the BBB. White matter lesions and microhemorrhages, dyslipidemia, altered brain insulin signaling, and insulin resistance contribute to tau and Aβ pathogenesis, and oxidative stress, mitochondrial damage, inflammation, and hypoperfusion serve as mechanistic links between pathophysiological features of AD and ischemia. Deregulated calcium homeostasis, voltage gated calcium channel functioning, and protein kinase C signaling are also common mechanisms for both AD pathogenesis and cerebrovascular abnormalities. Additionally, APOE polymorphic alleles that characterize impaired cerebrovascular integrity function as primary genetic determinants of AD. Overall, the current review enlightens key vascular risk factors for AD and underscores pathophysiologic relationship between AD and vascular dysfunction.

Clinical Profiles of Arteriolosclerosis and Alzheimer Disease at Mild Cognitive Impairment and Mild Dementia in a National Neuropathology Cohort

OBJECTIVE

We sought to evaluate early clinical differences between cerebral arteriolosclerosis (pARTE), Alzheimer disease (pAD), and AD with arteriolosclerosis (ADARTE).

METHODS

Using National Alzheimer's Coordinating Center neuropathology diagnoses, we defined pARTE (n=21), pAD (n=203), and ADARTE (n=158) groups. We compared demographics, medical history, psychometrics, neuropsychiatric symptoms, and apolipoprotein E (APOE) allele variants across neuropathology groups. Retrospective timepoints were first evaluation with Global Clinical Dementia Rating (CDR) score of 0.5 and 1.0, via the CDR Dementia Staging Instrument, corresponding to mild cognitive impairment (MCI) and mild dementia, respectively.

RESULTS

In MCI, clinical differences were minimal but pARTE subjects were older, had later onset cognitive decline, and progressed less severely than pAD. In mild dementia, pAD subjects were younger and had earlier onset of decline. Neuropsychiatric (depression) and psychometric (Logical Memory Delayed Recall, Trails B) differences also emerged between the groups. In MCI, APOE4 associated with worse Logical Memory Delayed Recall in pAD and ADARTE. In mild dementia, APOE4 associated with better animal fluency in pAD, but with better Trails A performance and more neuropsychiatric symptoms (Neuropsychiatric Inventory Questionnaire) in ADARTE.

CONCLUSIONS

Differences between pARTE, pAD, and ADARTE emerge at mild dementia rather than MCI. APOE4 has varied cognitive and psychiatric impact dependent on neuropathology group and stage.

Identification of a Rare PSEN1 Mutation (Thr119Ile) in Late-Onset Alzheimer's Disease With Early Presentation of Behavioral Disturbance

Alzheimer's disease (AD) is the most common form of neurodegenerative dementia. In this study, whole genome sequencing identifies one rare and likely pathogenic mutation in the presenilin 1 (PSEN1) gene (c.356C > T, p.T119I) associated with a frontal variant of AD. Affected individuals in the kindred developed late-onset cognitive decline accompanied with early presentation of psychiatric symptoms. Positive amyloid PiB PET tracing suggested presence of pathophysiological biomarker for AD. Whole genome sequencing analysis evaluated rare coding mutations in susceptible genes for various types of dementia and supported the role of PSEN1 as a causal gene. Identification of this T119I variant in PSEN1 might broaden the spectrum of genetic basis and clinical diversity of familial AD.

Genetics of Vascular Dementia: Systematic Review and Meta-Analysis

BACKGROUND

Vascular dementia (VaD) is the second most common type of dementia. So far, little is known about the contribution of genetic polymorphisms to the risk of VaD. Many candidate genetic polymorphisms have been examined in a large number of studies. However, due to the conflicting results, the genetics of VaD is still behind the shadow.

OBJECTIVE

We conducted a comprehensive meta-analysis on associations between genetic polymorphisms of any gene and VaD to investigate the genetics of VaD.

METHOD

We sought the published studies of associations between any genetic polymorphism and VaD and critically appraised them. We assessed the effects of genetic models by calculating pooled odds ratios (ORs), investigating the origin of heterogeneity by subgroup analysis, and testing the robustness by random effect model and sensitivity analysis.

RESULTS

69 studies with 4,462 cases and 11,583 controls were included. We identified APOE ɛ2/ɛ3/ɛ4 and additional four genetic polymorphisms including MTHFR C677T, PON1 L55M, TGF-β1 +29C/T, and TNF-α -850C/T associated with VaD. Tested by random effect model and sensitivity analysis, the pooled results show nice robustness.

CONCLUSIONS

Our comprehensive meta-analysis highlighted the genetic contribution to sporadic VaD. Because of the small amount of data on associations between genetic polymorphisms, except for APOE, and VaD, more studies are needed to test the existing genetic polymorphisms and detect other related genetic variants.

Polymorphisms of the neurotrophic factor-3 (NTF-3) in Alzheimer's disease: rs6332 associated with onset time and rs6489630 T allele exhibited a protective role

Because of its implications in neuroprotection, formation of long lasting memories and a disturbed function in Alzheimer's disease (AD), neurotrophin-3 (NTF-3) may represent an appropriate candidate gene conferring risk to AD. Recently, two single nucleotide polymorphisms (SNPs) (rs6489630 and rs6332) within the NTF-3 gene have been associated with AD in a Japanese population. Because of the importance of this finding, we analyzed the NTF-3 polymorphism in a Han Chinese sample consisting of 138 AD patients and 115 age-matched normal controls (NCs). In ApoE-ɛ4 non-carriers, a negative gene dose-association was found between the A allele of rs6332 and the onset time of AD. Individuals homozygous for the A allele developed AD significantly earlier than those homozygous for the G allele (mean age ± SD: 63.72 ± 9.08 versus 69.75 ± 6.03, p = 0.023). Moreover, in male subjects, we found the rs6489630 T allele to be protective against AD (OR 0.494; 95% CI 0.274-0.891; p value = 0.018) compared to C allele carriers. Due to a small number of patients showing homozygosity for the T allele in rs6489630 (n = 5), all of which were normal subjects, the result needs to be confirmed in a larger sample. The results suggest a gene dose-association between the A allele of rs6332 and the onset of AD in ɛ4 non-carriers, as well as the NTF-3 rs6489630 polymorphism being a relevant risk factor for AD in patients lacking the ApoE-ɛ4 allele in this Chinese sample.

Why therapies for Alzheimer's disease do not work: Do we have consensus over the path to follow?

Alzheimer's disease (AD) represents a personal tragedy of enormous magnitude, which imposes a daunting worldwide challenge for health-care providers and society as well. In last five decades, global research in clinics and laboratories has illuminated many features of this sinister and eventually fatal disease. Notwithstanding this development, the Alzheimer's research apparently has come across a phase of disappointment and a little reservation about the direction to follow. Persistently distressing controversies and a significant number of missing facts shed further uncertainty about the path forward. A detailed description of some of the main controversies in AD research may assist the field towards finding a resolution. Here I reviewed some alarming concerns or controversies related to these primary issues and emphasized on a possible mechanism to settle them.

Influence of the rs1080985 Single Nucleotide Polymorphism of the CYP2D6 Gene and APOE Polymorphism on the Response to Donepezil Treatment in Patients with Alzheimer's Disease in China

Background/Aim

Recent data have indicated that the rs1080985 single nucleotide polymorphism (SNP) of the cytochrome P450 (CYP) 2D6 and the common apolipoprotein E (APOE) gene may affect the response to donepezil in patients with Alzheimer's disease (AD). We investigated this association in Chinese patients with mild-to-moderate AD.

Methods

In this prospective cohort study, analyses of CYP2D6 and APOE were conducted in 208 native Chinese patients with mild-to-moderate AD. All patients were treated with donepezil 5 mg/day for 6 months, and the response to treatment was assessed using the Mini-Mental State Examination.

Results

No significant differences between responders (68.9%) and nonresponders (31.1%) to donepezil treatment (6 months' duration) were observed in the distribution of the CYP2D6 rs1080985 SNP, common APOE polymorphism or a combination of the two.

Conclusions

Our results suggest that neither the CYP2D6 nor the APOE polymorphism influences the 6-month response to donepezil treatment in a Chinese population with AD.

Apolipoprotein Ε ε4 frequency is increased among Chinese patients with frontotemporal dementia and Alzheimer's disease

The relationship between the apolipoprotein E (ApoE) ε4 genotype and an increased risk of developing Alzheimer's disease (AD) has been well established in Caucasians but is less established among other ethnicities. ApoE ε4 has also been associated with several other neurological disorders. Whether ApoΕ4 ε4 is a risk factor for frontotemporal dementia (FTD) remains controversial. This study examined 432 patients with AD, 62 with FTD, and 381 sex- and age-matched controls. The ApoE ε4 allele frequency was significantly increased among patients in the AD and FTD groups compared with controls. The frequency of the ApoΕ ε4 allele was 24.86% in late-onset AD (p < 0.01), 18.02% in early-onset AD (p < 0.01), 16.13% in FTD (p < 0.01), and 7.34% in controls. ApoΕ ε4 prevalence was similar in the FTD and AD groups. The present study suggests that the ApoE ε4 allele is a risk factor for both disorders.

Apolipoprotein E gene polymorphism in a Chinese population with vascular dementia: a meta-analysis

BACKGROUND

Apolipoprotein E (ApoE) gene has been reported to be associated with the development of vascular dementia (VD); however, results from observational studies are conflicting.

METHODS

We surveyed all case-control studies on ApoE gene and VD patients with comprehensive search and review of the references. A meta-analysis was performed to demonstrate the association of ApoE gene with VD by random effects models. The association was assessed by odds ratio (OR) with 95% confidence intervals (CI).

RESULTS

A total of 18 studies including 935 patients and 1,686 controls were eligible and abstracted. ApoE ε3/4 and ε4/4 genotype, as well as ε4 allele (OR = 1.95, 95% CI: 1.52-2.49; OR = 3.47, 95% CI: 1.85-6.51 and OR = 2.12, 95% CI: 1.64-2.74, respectively) were associated with an increased risk of VD, while ApoE ε3/3 genotype and ε3 allele (OR = 0.65, 95% CI: 0.53-0.79 and OR = 0.65, 95% CI: 0.53-0.80, respectively) trended to protect against VD. There was no significant difference in ApoE ε2 allele frequency, ε2/2, ε2/3 or ε2/4 genotype between VD and controls (OR = 0.85, 95% CI: 0.61-1.17; OR = 0.89, 95% CI: 0.39-2.01; OR = 0.82, 95% CI: 0.61-1.09 and OR = 1.03, 95% CI: 0.57-1.84, respectively).

CONCLUSIONS

Our results support a genetic association between ApoE polymorphism and VD in the Chinese population.

Lack of association between apolipoprotein E polymorphism and vascular dementia in Koreans

To investigate an association of vascular dementia (VD) with the apolipoprotein E (APOE) polymorphism, the APOE polymorphism of 100 VD patients, 100 age- and gender-matched Alzheimer disease (AD) patients, and 200 age- and gender-matched nondemented control (NC) subjects was genotyped. The distribution of APOE polymorphism was compared. Neither the APOE epsilon4 allele nor the APOE epsilon2 allele was more prevalent in the VD patients compared with the NC subjects (P > .1 by the chi 2 test), which was the case when both men and women were analyzed separately (P > .1 by the chi2 test) and when young patients (75 years old or less) and old patients (more than 75 years old) were analyzed separately (P > .1 by the chi2 test). The estimated statistical power was over 0.80 when the odds ratios (OR) for VD conferred to the APOE epsilon4 are assumed to be higher than 2.2 and the type I error probability is set at 0.05, which is much higher than the power of the previous studies on the VD/APOE association. In conclusion, the results suggested that APOE epsilon4 allele does not confer the risk for VD, and even if it does, it does so very modestly.

Genetics of ischaemic stroke among persons of non-European descent: a meta-analysis of eight genes involving approximately 32,500 individuals

BACKGROUND

Ischaemic stroke in persons of European descent has a genetic basis, but whether the stroke-susceptibility alleles, the strength of any association, and the extent of their attributable risks are the same in persons of non-European descent remains unanswered. Whether ethnicity itself has a relevant or substantial contribution on those effect estimates is controversial. Comparative analyses between the ethnic groups may allow general conclusions to be drawn about polygenic disorders.

METHODS AND FINDINGS

We performed a literature-based systematic review of genetic association studies in stroke in persons of non-European descent. Odds ratios (ORs) and 95% confidence intervals (CIs) were determined for each gene-disease association using fixed and random effect models. We further performed a comparative genetic analysis across the different ethnic groups (including persons of European descent derived from our previous meta-analysis) to determine if genetic risks varied by ethnicity. Following a review of 500 manuscripts, eight candidate gene variants were analysed among 32,431 individuals (12,883 cases and 19,548 controls), comprising mainly Chinese, Japanese, and Korean individuals. Of the eight candidate genes studied, three were associated with ischaemic stroke: the angiotensin I converting enzyme (ACE) insertion/deletion (I/D) polymorphism with a mean OR of 1.90 (95% CI 1.23-2.93) in the Chinese and 1.74 (95% CI 0.88-3.42) in the Japanese; the summary OR for the C677T variant of 5,10-methylenetetrahydrofolate reductase (MTHFR) was 1.18 (95% CI 0.90-1.56) in Chinese and 1.34 (95% CI 0.87-2.06) in Koreans; and the pooled OR for the apolipoprotein E (APOE) gene was 2.18 (95% CI 1.52-3.13) in Chinese and 1.51 (95% CI 0.93-2.45) in Japanese. Comparing the commonly investigated stroke genes among the Asian groups against studies in persons of European descent, we found an absence of any substantial qualitative or quantitative interaction for ORs by ethnicity. However, the number of individuals recruited per study in the studies of persons of non-European descent was significantly smaller compared to studies of persons of European descent, despite a similar number of studies conducted per gene.

CONCLUSIONS

These data suggest that genetic associations studied to date for ischaemic stroke among persons of non-European descent are similar to those for persons of European descent. Claims of differences in genetic effects among different ethnic populations for complex disorders such as stroke may be overstated. However, due to the limited number of gene variants evaluated, the relatively smaller number of individuals included in the meta-analyses of persons of non-European descent in stroke, and the possibility of publication bias, the existence of allele variants with differential effects by ethnicity cannot be excluded.

The apolipoprotein E epsilon4-allele and antihypertensive treatment are associated with increased risk of cerebral MRI white matter hyperintensities

OBJECTIVE

Apolipoprotein E-epsilon4 (APOE-epsilon4) is a potential risk factor for cerebral vascular disease. The aim of the present study was to examine the relative importance of APOE-epsilon4 and other relevant risk factors for the extent of cerebral white matter hyperintensity (WMH) in a community-based sample of elderly subjects.

MATERIALS AND METHODS

From a cohort of 976 subjects born in 1914, APOE genotype was determined and MRI examinations were carried out in 75 subjects. WMH were rated using a standard semi-quantitative method. ANOVA and regression analyses were conducted to explore the relative importance of the potential risk factors.

RESULTS

APOE genotype and antihypertensive treatment were significantly associated with severity of total WMH load (P < 0.05).

CONCLUSIONS

The study confirmed the association between APOE-epsilon4 and WMH. Pharmaceutical treatment for arterial hypertension was also associated with the total burden of WMH in this study.

Apolipoprotein E epsilon4 allele frequency in vascular dementia

AIM

The aim of the study was to investigate whether possession of the epsilon4 allelic form of the apolipoprotein E (APOE) gene increases the risk of developing vascular dementia (VaD).

METHODS

APOE allele and genotype frequencies were determined by PCR in 89 patients with possible and probable VaD and compared with those in 97 patients with possible and probable Alzheimer's disease (AD) of similar age of disease onset and ethnic background, and with 766 control subjects drawn from the same geographical region.

RESULTS

The APOE epsilon4 allele frequency in all 97 patients with possible and probable AD was significantly higher (p < 0.001) than that in control subjects. However, the APOE epsilon4 allele frequency in all 89 patients with possible and probable VaD was also significantly higher (p < 0.001) than that in control subjects, but not significantly different from that in AD. The APOE epsilon4 allele frequency was similarly, and still significantly (p < 0.001), increased when only those patients with probable AD or probable VaD were considered.

CONCLUSION

Possession of APOE epsilon4 allele increases the risk of VaD.

Differences in risk factors for dementia with neurodegenerative traits and for vascular dementia

In 229 patients with dementia and in 144 control subjects, polymorphisms of apolipoprotein E (ApoE), low-density-lipoprotein (LDL)-receptor-related protein, alpha(2)-macroglobulin, interleukin (IL) 1beta, angiotensin-converting enzyme and of methylene tetrahydrofolate reductase genes were investigated. In plasma, antibodies against Chlamydia pneumoniae and lipids were determined. Dementia was classified as probable Alzheimer's disease (AD), probable dementia of vascular origin (VaD) and mixed dementia (MD). An association of the disease with ApoE and IL-1beta polymorphism and increased levels of LDL cholesterol were observed in AD and in MD but not in VaD.

Fluvastatin Ameliorates Podocyte Injury in Proteinuric RatsviaModulation of Excessive Rho Signaling

Statins have been reported to confer renoprotection in several experimental models of renal disease through pleiotropic actions. The roles of statins in glomerular podocytes have not been explored. The objective of this study was to evaluate the effects of fluvastatin on podocyte and tubulointerstitial injury in puromycin aminonucleoside (PAN)-induced nephrosis. PAN induced massive proteinuria and serum creatinine elevation on day 7, which were significantly suppressed by fluvastatin. Immunofluorescence studies of podocyte-associated proteins nephrin and podocin revealed diminished and discontinuous staining patterns in rats with PAN nephrosis, indicating severe podocyte injury. Fluvastatin treatment dramatically mitigated the abnormal staining profiles. Reduction of nephrin expression by PAN and its reversal by fluvastatin were confirmed by quantitative analyses. By electron microscopy, effacement of foot processes was ameliorated in fluvastatin-treated rats. Fluvastatin also mitigated tubulointerstitial damage in PAN nephrosis, with the repression of PAN-induced NF-kappaB and activator protein-1 activation in the kidneys. In addition, expression of activated membrane-bound small GTPase RhoA was markedly increased in the glomeruli of PAN nephrosis, which was inhibited by fluvastatin treatment. In cultured podocytes, fluvastatin suppressed PAN-evoked activation of RhoA and actin cytoskeletal reorganization. Furthermore, fasudil, a specific Rho-kinase inhibitor, successfully ameliorated PAN-induced podocyte damage and proteinuria. In summary, fluvastatin alleviated podocyte and tubulointerstitial injury in PAN nephrosis. The beneficial effects of fluvastatin on podocytes can be attributable to direct modulation of excessive RhoA activity. Our data suggest a therapeutic role for statins in clinical conditions that are relevant to podocyte injury.

A haplotype of the methylenetetrahydrofolate reductase gene is protective against late-onset Alzheimer's disease

Epidemiological studies have shown that elevated plasma homocysteine (Hcy) levels play an important role in the pathogenesis of Alzheimer's disease (AD). In spite of the evidence that a C677T polymorphism in the methylenetetrahydrofolate reductase (MTHFR) gene elevates plasma Hcy levels, the impact of the C677T polymorphism on the development of AD is controversial. Here, we performed a genetic case-control study in a Japanese population to investigate whether three polymorphisms of the MTHFR gene, C677T (Ala222Val), A1298C (Glu429Ala), and A1793G (Arg594Gln), are associated with the development of late-onset AD (LOAD). In our study, the MTHFR gene had four major regional haplotypes: Haplotype A (677C-1298A-1793G), Haplotype B (677T-1298A-1793G), Haplotype C (677C-1298C-1793G), and Haplotype D (677C-1298C-1793A). The frequency of Haplotype C in LOAD was significantly lower than that in control group. Furthermore, the benefit conferred by the presence of at least one Haplotype C was stronger in LOAD patients who lacked the ApoE 4 allele (OR=0.293; 95% CI=0.115-0.744; P=0.010). The results indicate that Haplotype C of the MTHFR gene is protective against the development of LOAD.

The regulatory region polymorphisms of the MTHFR gene are not associated with Alzheimer's disease

Recent epidemiological studies have emphasized the impact of elevated blood homocysteine levels on the pathogenesis of Alzheimer's disease (AD). In spite of a significant impact of a MTHFR C677T polymorphism on the blood homocysteine levels, the association between the C677T polymorphism and AD remains controversial. Therefore, other unidentified genetic factor(s) that regulate blood homocysteine levels may exist. Here, we have analyzed the 5'-upstream region of the MTHFR gene and examined AD patients (n = 223) and nondemented individuals (n = 323) for polymorphisms in the 5'-upstream region of the MTHFR gene. We identified two polymorphisms (-713G/A and -393C/A, upstream of the start codon). We found no significant relationship between AD and the 5'-upstream region polymorphisms of the MTHFR gene. Thus, our study does not reinforce the hypothesis of an independent involvement of the MTHFR gene upstream region polymorphisms in AD risk.

Apolipoprotein E Polymorphism in Ischemic Cerebrovascular Diseases and Vascular Dementia Patients in Taiwan

This study aims to clarify the association between apolipoprotein E gene (ApoE) polymorphism, ischemic cerebrovascular diseases (ICVD) and vascular dementia (VaD) in Taiwan Chinese. 277 patients with ICVD, 49 patients with probable VaD and 112 controls were recruited for this study. Distributions of ApoE epsilon4 carriers and allele frequencies were 28.5 and 14.5% for patients with ICVD, 20.4 and 10.2% for patients with VaD, whereas these values were 22.9 and 11.6% for controls. Distributions of ApoE epsilon2 carriers and allele frequencies were 10.1 and 5.2% for ICVD patients, 6.1 and 3.1% for VaD patients, but 12.5 and 8.0% for controls. There were no differences between ICVD patients and controls, or VaD patients and controls in their epsilon4 carriers. Those patients aged 65 and under, carrying the epsilon2 allele, had a lower risk of developing ICVD and VaD than did their counterparts. These findings suggest that ApoE epsilon4 plays no significant role in the development of ICVD and VaD, but that ApoE epsilon2 has a protective effect with regard to the development of ICVD and VaD for Taiwan Chinese below the age of 65.

Is Alzheimer's disease a neurodegenerative or a vascular disorder? Data, dogma, and dialectics

The cause of Alzheimer's disease (AD) is unknown. This gap in knowledge has created a stumbling block in the search for a genuinely effective treatment or cure for this dementia. This article summarises the arguments for a causal role for either amyloid deposition or cerebrovascular pathology as the primary trigger in the development of non-genetic AD. A bare-bones survey of the published research reveals no compelling evidence that amyloid deposition is neurotoxic in human beings or that it results in neurodegenerative changes involving synaptic, metabolic, or neuronal loss in human or transgenic-mouse brains. By contrast, the data supporting AD as a primary vascular disorder are more convincing. Findings suggesting a vascular cause of AD come from epidemiological, neuroimaging, pathological, pharmacotherapeutic, and clinical studies. The consensus of these studies indicates that chronic brain hypoperfusion is linked to AD risk factors, AD preclinical detection and pharmacotherapeutic action of AD symptoms.

Apolipoprotein e gene polymorphism as a risk factor for ischemic cerebrovascular disease

The possible association of apolipoprotein E (apoE) DNA polymorphism with ischemic cerebrovascular disease was evaluated in 65 patients who had suffered completed stroke or transient ischemic attack and 330 healthy controls. ApoE genotypes were determined by restriction isotyping/MADGE analysis. Significant difference in apoE genotype frequencies between case and control group was observed (p<0.01). Patients affected by ischemic stroke had higher frequency of E4 allele and lower E2 allele than age-matched control subjects. Compared with persons without E4 allele, carriers of an E4 allele had 2.1 times higher risk of incident stroke. Our results indicate that the apoE gene polymorphism may be a risk factor for the development of ischemic cerebrovascular disease in Serbian population..

Apolipoprotein E in Taiwan Chinese patients with dementia

To clarify whether Alzheimer's disease (AD) and vascular dementia (VaD) share the same risk factors in Taiwan Chinese patients. Using the criteria of the NINCDS- ADRDA and NINDS-AIREN, 154 AD patients, 30 VaD patients, and 112 controls were enrolled. Their apolipoprotein E (ApoE) genes, extracted from peripheral blood leukocytes, were analyzed. The epsilon4 allele frequency was significantly higher in AD patients than in the control group. The odds ratio of carrying at least one copy of the epsilon4 allele in AD patients is 2.7 compared with control subjects. There was no significant difference between the VaD patients and the control subjects in their ApoE epsilon4 or epsilon2 allele frequency. The present study demonstrates a strong association between the ApoE epsilon4 allele and AD, but not between the ApoE epsilon4 allele and VaD. This suggests that AD and VaD do not share the same pathogenesis and deserve further investigation.

Association between apolipoprotein E4 and rehabilitation outcome in hospitalized ischemic stroke patients

OBJECTIVE

To determine the value of apolipoprotein E4 (APOE*E4) allele in predicting discharge impairment and disability in ischemic stroke patients after acute rehabilitation.

DESIGN

Prospective study comparing results of rehabilitation in patients with different APOE genotypes.

SETTING

Acute neurologic rehabilitation department in Israel.

PARTICIPANTS

One hundred one consecutive patients 75 years old or less with a first ischemic stroke.

INTERVENTIONS

Not applicable.

MAIN OUTCOME MEASURE

Impairment, as measured by the National Institutes of Health Stroke Scale (NIHSS), and disability, as assessed with the FIM trade mark instrument.

RESULTS

On admission, there was no significant difference in the FIM or NIHSS measurements between the apo E4 group and other patients, but the prevalence of aphasia was 2.07 times more frequent in those with the APOE*E4 genotype (95% confidence interval, 0.98-4.4). A logistic regression model demonstrated that score measurements on admission were highly predictive of the NIHSS score at discharge (receiver operator curve=96.1%), whereas the presence of the APOE*E4 genotype did not add significantly to the model in predicting poorer rehabilitation treatment outcome as measured by the FIM or the NIHSS.

CONCLUSIONS

The presence of the apo E4 allele did not predict a poorer outcome of rehabilitation treatment after ischemic stroke, but it was associated with an increased prevalence of aphasia. Further studies are warranted to confirm this association.

Pentosidine and N(epsilon)-(carboxymethyl)-lysine in Alzheimer's disease and vascular dementia

Increasing evidence suggests an interaction of oxidative stress and the formation of advanced glycation end products (AGE) in the onset and progression of Alzheimer's disease. We studied levels of pentosidine and N(epsilon)-(carboxymethyl)-lysine (CML) in serum and cerebrospinal fluid (CSF) of 15 patients with probable Alzheimer's disease (AD), 20 patients with vascular dementia (VD), and 31 control subjects (14 matched for age, and 17 younger patients). AGE protein concentrations in CSF did not differ within controls when divided into two subgroups by age. We found significantly elevated levels of CML in CSF of AD patients and of pentosidine in CSF of patients suffering from vascular dementia when compared to controls. The concentrations of pentosidine and CML in serum apparently did not relate directly to CSF values, suggesting influence of extra-cerebral factors in serum samples. It is concluded that AGE proteins are differentially affected in these types of dementia, depending on the specific neuropathology. Furthermore, measurements of AGE products in vivo should rely on CSF rather than blood samples.

Genetic analysis of vascular factors in Alzheimer's disease

Genetic risk factors for Alzheimer's disease (AD) have been extensively examined. Several risk factors for AD are shared with vascular dementia (VaD). We performed genetic case-control studies on polymorphisms of the apolipoprotein E (ApoE) gene, the methylene tetrahydrofolate reductase (MTHFR) gene, and the angiotensin-converting enzyme (ACE) gene. The most acceptable genetic risk factor for the development of AD is the ApoE epsilon-4 (ApoE epsilon4) allele. ApoE promoter polymorphisms have also been reported to be associated with AD. As expected, the ApoE epsilon4 allele had strong association with AD in our samples. The ApoE epsilon4 allele was also estimated as a risk factor for VaD. An ApoE promoter polymorphism (-291T/G) did not show positive association with AD or any other diseases. Common MTHFR phenotypes are thought to genetically regulate blood homocysteine level, which has been associated with AD. We failed to show independent associations between AD and the common MTHFR polymorphisms (C677T and A1298C). A deletion polymorphism at intron 16 of the ACE gene has also been associated with AD. In our study, we found a significant ethnic difference of the genotype distribution, but failed to replicate the positive association between the I allele and AD.

Apolipoprotein E epsilon 4 allele is not associated with the cognitive impairment in community-dwelling normal elderly individuals

OBJECTIVES

The aim of this study was to examine whether the APOE epsilon 4 allele also confers a risk for the cognitive impairment in normal aging.

METHODS

We administered all the eight neuropsychological tests from the CERAD neuropsychological battery to the CVD-free, community-dwelling normal elderly individuals, and compared their performance by the occurrence of the APOE epsilon 4 allele.

RESULTS

Either the impact of APOE epsilon 4 allele itself or its interaction terms with age and gender of the subjects did not influence the performance of the eight neuropsychological tests (epsilon p > 0.1 by ANCOVA).

CONCLUSIONS

The APOE epsilon 4 allele is not a risk factor for the cognitive decline in normal elderly individuals regardless of age and gender.

Apolipoprotein E genotype and cognitive impairment in community-dwelling black older adults

OBJECTIVE

The relationship between the epsilon 4 allele of the apolipoprotein E gene (APOE-epsilon4) located on chromosome 19 and Alzheimer's disease is well documented among Caucasian populations. However, the findings of research addressing the link between APOE polymorphism and neurocognitive functioning in populations of African origin from around the world have been equivocal. Therefore, the current study explored the relation of APOE-epsilon4 with cognitive impairment in a sample of community-dwelling English-speaking elderly blacks.

METHODS

All participants (N = 57) were recruited consecutively from a community memory-screening program at a University affiliated Memory Disorders Clinic and evaluated using standardized assessment procedures. Cognitive impairment was classified according to an age and education adjusted Mini-Mental State Exam score of less than 24 as well as poorer functioning on a measure of delayed verbal memory.

RESULTS

Increased risk for global cognitive dysfunction (OR = 9.5, 95 percent CI = 2.3-55.3, p = .004) and poorer verbal recall performance (beta = -.36, p = .006) were linked with the APOE epsilon4 allele after controlling for the potentially confounding effects of age, education, and gender.

CONCLUSIONS

This investigation supports the role of APOE polymorphism in determining neurocognitive impairment among black elders residing in the community.

Apolipoprotein E polymorphism and cognitive impairment in a bi-ethnic community-dwelling elderly sample

The epsilon 4 (epsilon 4) and epsilon 2 (epsilon 2) alleles of the apolipoprotein gene (APOE) located on chromosome 19 have been associated with increased and decreased risk for Alzheimer disease (AD) in older adults, respectively. However, there is a dearth of studies examining the relation of APOE polymorphism with cognitive functioning among community-dwelling ethnic minority elderly. This study examined the risk for cognitive impairment associated with the APOE epsilon 4 and epsilon 2 alleles in a community-based cohort of non-Hispanic white (NHW; N = 739) and white Hispanics (WH; N=321). All patients were recruited consecutively from a memory-screening program and evaluated using standardized assessment procedures. Cognitive impairment was classified according to an age and education adjusted Folstein Mini-Mental State Exam (MMSAdj) score of less than 24. The results indicated the APOE epsilon 4 allele was associated with increased risk for cognitive dysfunction in NHW and WH after controlling for the effects of age, education, and gender. This risk was generally observed to be dose-dependent, with greater risk among epsilon 4 homozygotes in relation to epsilon 4 heterozygotes. The epsilon 2 allele of APOE did not confer decreased risk for cognitive impairment among NHW and WH. This study supports the relation of APOE polymorphism to cognitive dysfunction among two ethnic populations residing in the community.

High expression of apolipoprotein E mRNA in the brains with sporadic Alzheimer's disease

In order to study progressive dementia in Alzheimer's disease (AD) patients, we analyzed the gene expression of apolipoprotein E (apoE). ApoE mRNA level in the brains of patients with AD was determined by the reverse transcriptase-polymerase chain reaction (RT-PCR) method. ApoE genotype and the promoter polymorphisms (-491A/T, Th1/E47cs) were determined by the PCR restriction fragment length polymorphism method. The apoE mRNA level was significantly higher in the AD group than the control group (p < 0.05). ApoE mRNA in the AD group with apoE epsilon 4 was also significantly higher than that in the control group with apoE epsilon 4 (p < 0.05). Our result did not indicate the possibility that the promoter polymorphisms modulate the apoE mRNA level. The higher level of apoE mRNA in AD with apoE epsilon4 may play an important role in the development of AD.

Neuronal apoptosis by apolipoprotein E4 through low-density lipoprotein receptor-related protein and heterotrimeric GTPases

The epsilon4 genotype of apolipoprotein E (apoE4) is the most established predisposing factor in Alzheimer's disease (AD); however, it remains unclear how apoE4 contributes to the pathophysiology. Here, we report that the apoE4 protein (ApoE4) evokes apoptosis in neuronal cells through the low-density lipoprotein receptor-related protein (LRP) and heterotrimeric GTPases. We examined neuron/neuroblastoma hybrid F11 cells and found that these cells were killed by 30 microg/ml ApoE4, but not by 30 microg/ml ApoE3. ApoE4-induced death occurred with typical features for apoptosis in time- and dose-dependent manners, and was observed in SH-SY5Y neuroblastomas, but not in glioblastomas or non-neuronal Chinese hamster ovary cells. Activated, but not native, alpha2-macroglobulin suppressed this ApoE4 toxicity. Suppression by the antisense oligonucleotide to LRP and inhibition by low nanomolar concentrations of LRP-associated protein RAP provided evidence for the involvement of LRP. The involvement of heterotrimeric GTPases was demonstrated by the findings that (1) ApoE4-induced death was suppressed by pertussis toxin (PTX), but not by heat-inactivated PTX; and (2) transfection with PTX-resistant mutant cDNAs of Galpha(i) restored the toxicity of ApoE4 restricted by PTX. We thus conclude that one of the neurotoxic mechanisms triggered by ApoE4 is to activate a cell type-specific apoptogenic program involving LRP and the G(i) class of GTPases and that the apoE4 gene may play a direct role in the pathogenesis of AD and other forms of dementia.

Neuronal cell apoptosis by a receptor-binding domain peptide of ApoE4, not through low-density lipoprotein receptor-related protein

Since an apolipoprotein E4 (ApoE4) peptide composed of the low-density lipoprotein (LDL) receptor-related protein (LRP)-binding domain [ApoE4(141-149)(2) or ApoE(141-155)(2)] exerts neurotoxicity in primary neurons and neuronal cell lines, it has been controversial whether these effects are mediated by LRP. Here, we examined whether ApoE4(141-149)(2)-induced toxicity is mediated by LRP in a neuronal cell system where ApoE4 toxicity is mediated by LRP: serum-deprived F11 neuronal cells. In these cells, where ApoE4 exerted toxicity by apoptosis in a manner sensitive to both caspase inhibitors and pertussis toxin (PTX), ApoE4(141-149)(2) also caused cell death by apoptosis but in a caspase-inhibitor-resistant, PTX-resistant manner. ApoE4(141-149)(2)-induced death was not inhibited by antisense oligonucleotides to LRP. Therefore, we conclude that ApoE4(141-149)(2) is able to exert neurotoxicity without involving LRP.

Cerebral hypoperfusion, capillary degeneration, and development of Alzheimer disease

Considerable clinical and experimental data have shown that cerebral perfusion is progressively decreased during increased aging and that this decrease in brain blood flow is significantly greater in Alzheimer disease (AD). The authors propose that advanced aging with a comorbid condition, such as a vascular risk factor, which further decreases cerebral perfusion, promotes a critically attained threshold of cerebral hypoperfusion (CATCH). With time, CATCH induces brain capillary degeneration and suboptimal delivery of energy substrates to neuronal tissue. Because glucose is the main fuel of brain cells, its impaired delivery, with the deficient delivery of oxygen, compromises neuronal stability because the supply for aerobic glycolysis fails to meet brain tissue demand. The outcome of CATCH is a metabolic cascade that involves, among other things, mitochondrial dysfunction, oxidative stress, decreased adenosine triphosphate production, abnormal protein synthesis, cell ionic pump deficiency, signal transduction defects, and neurotransmission failure. These events contribute to the progressive cognitive decline characteristic of patients with AD, as well as regional anatomic pathology, consisting of synaptic loss, senile plaques, neurofibrillary tangles, tissue atrophy, and neurodegeneration. CATCH identifies the clinical heterogeneic pattern that characterizes AD because it provides compelling evidence that any of a multitude of different etiopathophysiologic vascular risk factors, in the presence of advanced aging, can lead to AD. The evidence in support of CATCH as the pathogenic trigger of AD is crystallized in this review.

A polymorphism in the cystatin C gene is a novel risk factor for late-onset Alzheimer's disease

OBJECTIVE

To investigate whether or not a coding polymorphism in the cystatin C gene (CST3) contributes risk for AD.

DESIGN

A case-control genetic association study of a Caucasian dataset of 309 clinic- and community-based cases and 134 community-based controls.

RESULTS

The authors find a signficant interaction between the GG genotype of CST3 and age/age of onset on risk for AD, such that in the over-80 age group the GG genotype contributes two-fold increased risk for the disease. The authors also see a trend toward interaction between APOE epsilon4-carrying genotype and age/age of onset in this dataset, but in the case of APOE the risk decreases with age. Analysis of only the community-based cases versus controls reveals a significant three-way interaction between APOE, CST3 and age/age of onset.

CONCLUSION

The reduced or absent risk for AD conferred by APOE in older populations has been well reported in the literature, prompting the suggestion that additional genetic risk factors confer risk for later-onset AD. In the author's dataset the opposite effects of APOE and CST3 genotype on risk for AD with increasing age suggest that CST3 is one of the risk factors for later-onset AD. Although the functional significance of this coding polymorphism has not yet been reported, several hypotheses can be proposed as to how variation in an amyloidogenic cysteine protease inhibitor may have pathologic consequences for AD.

Vascular dementia : incidence and risk factors in the Canadian study of health and aging

BACKGROUND AND PURPOSE

Very few population-based studies have systematically examined incident vascular dementia (VaD). From the Canadian Study of Health and Aging cohort, incidence rates of VaD were determined and risk factors analyzed.

METHODS

This was a cohort incidence study that followed 8623 subjects presumed to be free of dementia over a 5-year period. The risk factors were examined with a nested prospective case-control study. Exposure was determined by means of a risk factor questionnaire administered to the subject or a proxy at the beginning of the study.

RESULTS

On the basis of 38 476 person-years at risk, the annual incidence rate was estimated to be 2.52 per thousand undemented Canadians (95% CI 2. 02 to 3.02). Including an estimation of the probability of VaD among the decedents, this figure rose to 3.79. For the risk factors study, 105 incident cases of VaD according to the NINCDS-AIREN criteria were compared with 802 control subjects. Significant risk factors were: age (OR=1.05), residing in a rural area (2.03), living in an institution (2.33), diabetes (2.15), depression (2.41), apolipoprotein E epsilon4 (2.34), hypertension for women (2.05), heart problems for men (2.52), taking aspirin (2.33), and occupational exposure to pesticides or fertilizers (2.05). Protective factors were eating shellfish (0.46) and regular exercise for women (0.46). There was no relation with sex, education, or alcohol.

CONCLUSIONS

The study confirmed some previously reported risk factors but also suggested new ones. It raised concerns about the prescription of aspirin and perhaps other factors related to rural life.

Chlamydia pneumoniae and cardiovascular disease: an evolutionary perspective on infectious causation and antibiotic treatment

Evolutionary considerations implicate infectious causation of atherosclerosis and help to resolve different risk factors as parts of an overall process of disease causation. An evolutionary approach also provides insight for the timing of research efforts to provide better control of pathogen evolution. In particular, evolutionary considerations emphasize the need to understand the transmissibility of Chlamydia pneumoniae from systemic infections in order to control the evolution of antibiotic resistance.

Estrogen receptor gene polymorphisms in patients with Alzheimer's disease, vascular dementia and alcohol-associated dementia

The association between the estrogen receptor (ER-alpha) gene and dementia was examined in 223 patients with Alzheimer's disease (AD), 66 with vascular dementia (VD), 17 with alcohol-associated dementia (ALD) and 134 healthy elderly control subjects. The PvuII and XbaI restriction fragment length polymorphisms of the ER-alpha gene were represented as Pp (PvuII) and Xx (XbaI), with capital letters signifying the absence of restriction sites and small letters the presence of restriction sites. We found that the frequency of the ER-alpha gene P allele and X allele in the late-onset AD (LOAD) group (P allele was 0.51, X allele was 0.30) was significantly higher than that in controls (P 0.38, p < 0.01; X 0.20, p < 0.01), and that the frequency of the ER-alpha gene P allele and PP genotype was significantly different between apolipoprotein E epsilon4 carriers and noncarriers in LOAD. These findings suggest that the genotype of the ER-alpha gene may be specific in LOAD, and that the ER-alpha gene was an additional risk for LOAD.

Which vascular lesions are of importance in vascular dementia?

Most necropsy surveys of dementia have found that vascular disease is second only to Alzheimer's disease as a cause of dementia. Alzheimer's disease and cerebrovascular disease also often coexist. The purpose of the present study was to determine the nature of the cerebrovascular lesions that are most significant in producing dementia. These were analyzed in a group of cases of dementia in which only vascular pathology was present and, in particular, no more than trivial amounts of Alzheimer-type pathology were present. The cerebrovascular lesions in this group of cases were compared with those in a group of stroke cases who were nondemented and a group of elderly cases without stroke or dementia. Severe cribriform change and deep white/grey matter micro-infarcts were significantly more common in the test group than in either of the control groups, whereas single macroscopic infarcts were more common in the stroke control group than either of the other two groups. Thus, microvascular deep white and grey matter lesions, but not macroscopic infarction, were significant in vascular dementia. The results of this study will be discussed in relation to the view that microvascular lesions may also contribute to dementia in subjects with more extensive Alzheimer-type pathology and thus lower the threshold at which Alzheimer-type pathology becomes clinically manifest.

Intake of flavonoids and risk of dementia

It has been postulated that oxidative stress may play a key role in dementia. This is substantiated by the recent discovery of the protective effect of wine. In wine, the flavonoids--powerful antioxidant substances also contained in tea, fruits and vegetables--have been thought to offer such protection. We investigated whether flavonoid intake could be associated with a lower incidence of dementia in a cohort of 1367 subjects above 65 years of age (Paquid). A questionnaire was used to evaluate their intake of flavonoids and subjects were followed-up for 5 years between 1991 and 1996: 66 incident cases of dementia were observed. We estimated the relative risk (RR) of dementia according to tertiles of flavonoid intake using a Cox model. The age-adjusted RR of dementia was 0.55 for the two highest tertiles compared to the lowest (95% CI: 0.34-0.90; p = 0.02). After additional adjustment for gender, education, weight and vitamin C intake, the RR was 0.49 (95% CI: 0.26-0.92; p = 0.04). We conclude that the intake of antioxidant flavonoids is inversely related to the risk of incident dementia.

Apolipoprotein E phenotypes in healthy normal controls and demented subjects with Alzheimer's disease and vascular dementia in Mie Prefecture of Japan

In order to clarify the association between apolipoprotein E4 (ApoE4) and the pathogenesis of Alzheimer's disease (AD), we analyzed the distribution of the apolipoprotein E (ApoE) phenotypes and the frequency of the apo E alleles epsilon2, epsilon3, and epsilon4 in Japanese healthy controls (n = 1090, an average age of 51.2+/-12.6 years) and demented patients (n=103, mean age of 73.6+/-9.2 years). Demented subjects were divided into three subgroups: early-onset AD group (EOAD; n=25, mean age 63.0+/-6.2 years), late-onset AD group (LOAD; n=33, mean age 79.3+/-5.1 years), and vascular dementia group (VD; n=45, mean age 75.3+/-8.0 years). The apolipoprotein E phenotype was determined by isoelectric focusing and immunoblotting. There were no significant differences in the distribution of the apo E phenotypes by gender or age, and the estimated frequencies of epsilon2, epsilon3 and epsilon4 were 0.05, 0.86 and 0.09, respectively, in the normal controls. There was a significant difference in the distribution of the apo E phenotypes between LOAD and elderly controls aged more than 65 years (P<0.0001). The distribution of the apo E phenotypes in EOAD was the same as that in LOAD. The frequency of the epsilon4 allele was significantly higher in LOAD (0.35, P<0.0001) and EOAD (0.28, P<0.0001) than that in the control subjects (0.07), but not in VD (0.12, P=0.1630). The present findings suggest that ApoE4 is related with both EOAD and LOAD, but not with VD, and support the hypothesis that it is a genetic risk factor of AD.

No association between apolipoprotein A-IV codon 360 mutation and late-onset Alzheimer's disease in the Japanese population

Human apolipoprotein A-IV (apoA-IV) is genetically polymorphic, the apoA-IV polymorphism being controlled by two alleles, apoA-IV1 and apoA-IV2. The association between the apoA-IV2 allele and late-onset Alzheimer's disease (LOAD) has been reported in Caucasian populations. We investigated the codon 360 mutation of the apoA-IV gene allele frequency in 173 LOAD and in 158 age-matched control subjects of the Japanese population, and we found that the allele frequency of apoA-IV2 in the Japanese population was very rare and was extremely lower than in Caucasian populations. We conclude that there was no association between apoA-IV genotype and LOAD in the Japanese population. Copyrightz1999S.KargerAG,Basel