Catalytic properties of the purified rat hepatic cytosolic cholesteryl ester hydrolase

Alzheimer's disease (AD) is a heterogeneous entity presenting as sporadic and familial disease. In familial AD, there is evidence for genetic linkage to a yet undefined gene on chromosome 14 in early-onset pedigrees and on chromosome 19 in late-onset pedigrees. In a few early-onset kindreds, there were mutations in the amyloid precursor gene on chromosome 21. There is an increased frequency of apolipoprotein E (ApoE) epsilon4 allele in patients with late-onset AD. We studied the clinical presentation and profile of cognitive deficits in 58 AD patients at the early stage of the disease. We divided the AD patients into subgroups of sporadic late-onset (SLO) (> or = 65 years), familial late-onset (FLO) (> or = 65 years), sporadic early-onset (SEO) (<65 years), and familial early-onset (FEO) (<65 years) patients and into three subgroups according to their ApoE genotype zero epsilon4, one epsilon4, and two epsilon4 alleles. The AD subgroups did not differ in the global clinical severity of dementia or the duration of the disease. SLO, FLO, SEO, and FEO subgroups did not differ in clinical characteristics such as occurrence of rigidity, hypokinesia, tremor, myoclonus, hallucinations, delusions, or epileptic seizures nor in the profile of deficits on tests assessing memory, language, visuospatial, executive, and praxic functions. The epsilon4++ allele frequency was 0.43 for all AD patients and did not differ across subgroups divided according to the familial aggregation and age of onset. Patients with two epsilon4 alleles had earlier age at onset of dementia than those with no epsilon4 allele (63 +/- 9 versus 68 +/- 9 years), but otherwise the clinical symptoms and signs were not related to the ApoE genotype. However, the AD patients with two epsilon 4 alleles had lowest scores on memory tests and differed significantly from those with one or zero epsilon4 allele in the delayed list learning (p<0.05) and from those with zero epsilon4 allele in the immediate and delayed story recall. In contrast, verbal functions were better preserved in two epsilon4 patients than in those with other ApoE genotypes. This study failed to confirm the earlier reports of severe aphasia, agnosia, and apraxia in familial AD patients, but the clinical phenotype was similar irrespective to the familial aggregation. However, AD patients with two epsilon4 alleles are characterized by more severe memory loss and earlier age of onset than those without the epsilon4 allele.     

ApoE allele frequencies in Italian sporadic and familial Alzheimer's disease

Recent studies have provided evidence of association of apolipoprotein E (ApoE) epsilon 4 allele and late onset familial and sporadic Alzheimer's disease (AD). Epidemiological studies have established allelic variation at the ApoE locus. We have analyzed the ApoE gene polymorphism in a sample of 446 Italian subjects. Our data confirm a significant association between epsilon 4 allele and sporadic AD. The frequency of epsilon 4 allele in early onset familial AD patients was comparable to control values suggesting that epsilon 4 allele does not represent a risk factor for early onset familial AD (EOFAD). Moreover, we found a not previously reported association between ApoE epsilon 2 allele and sporadic AD and EOFAD.     

Apolipoprotein E genotype as a risk factor in Japanese patients with early-onset and late-onset Alzheimer's disease

Recent studies have provided evidence of an association of apolipoprotein E (apoE) epsilon 4 allele and late-onset sporadic Alzheimer's disease (AD). Some studies have shown the possibility that apoE epsilon 4 is a risk factor of developing AD in early-onset type. We have analyzed the apoE gene polymorphism in a sample of 310 Japanese AD subjects and 237 age-matched Japanese controls. We divided the sporadic AD patients into two subgroups of 237 late-onset (> 65 years) and 73 early-onset (< or = 65 years) patients, and into three subgroups according to their apoE genotype, no epsilon 4, one epsilon 4, and two epsilon 4 alleles. Our data confirmed an association between epsilon 4 allele and early-onset AD and late-onset AD. The odds ratios (95% confidence interval) referred to no epsilon 4 allele for AD were 3.4 (1.7-7.0) for one epsilon 4 allele and 20.3 (2.5-166.6) for two epsilon 4 alleles in early-onset type, and 6.7 (3.9-11.3) for one epsilon 4 allele and 19.0 (2.5-145.6) for two epsilon 4 alleles in late-onset type. These ratios were significantly increased in both early-onset AD and late-onset AD. Kaplan-Meier survival analysis, which estimates the age of onset for subjects with no, one, and two epsilon 4 alleles in early-onset and late-onset type, revealed a significant dose effect where each additional epsilon 4 allele made the age of onset earlier (p < 0.0001). The age of onset is 9.7 years earlier for two epsilon 4 bearers and 3.9 years earlier for one epsilon 4 bearers than no epsilon 4 bearers in late-onset AD, 2.9 years earlier for two epsilon 4 bearers and 1.4 years earlier for one epsilon 4 bearers than no epsilon 4 bearers in early-onset AD. Moreover, we studied an association between apoE epsilon 2 allele and early-onset AD and late-onset AD. There was a significantly decreased frequency of apoE epsilon 2 allele in patients with late-onset AD (p = 0.026), although the frequency of apoE epsilon 2 was not changed significantly in early-onset AD (p = 0.360). The odds ratios referred to no epsilon 2 allele for AD were 1.9 (0.6-5.7) for one epsilon 2 allele in early-onset type, and 0.4 (0.2-0.9) for one epsilon 2 allele in late-onset type. Our study suggested the difference in the effect of apoE genotype on developing AD between early-onset and late-onset type in Japanese patients.     

Molecular genetics of Alzheimer's disease--presenilin and other genes

We examined mutations of presenilin 1 (PS1), presenilin 2 (PS2) and amyloid precursor protein (APP) in 30 Japanese familial Alzheimer's disease (FAD) and 34 isolated cases of Alzheimer's disease (AD). We found mutations of PS1 in 17% of early onset FAD (H163R, H163R, R269H, E273A, G384A) and in a case (H163R) of isolated AD. The remaining cases were free from mutations in PS1, PS2 and APP. Since only a part of them could he explained by ApoE epsilon 4, we concluded that important genes are missing. We also examined association of apolipoprotein E (ApoE)epsilon 4, allele A of alpha 1-antichymotrypsin (ACT), 5 repeat allele of very low density lipoprotein receptor (VLDLR) and Alzheimer's disease. We confirmed that ApoE espilon 4 is significantly more frequent in both FAD and isolated AD cases than controls. We could not see any significant association in the ACT polymorphism. The 5 repeat allele of VLDLR was slightly but significantly more frequent in AD cases than controls. However, association with ApoE epsilon 4 was not seen in our study.     

Co-expression of beta-amyloid precursor protein (betaAPP) and apolipoprotein E in cell culture: analysis of betaAPP processing

Apolipoprotein E (ApoE) is the major genetic risk factor for Alzheimer's disease (AD). The ApoE4 allele is associated with earlier disease onset and greater cerebral deposition of the amyloid beta peptide (Abeta), the major constituent of senile (amyloid) plaques. The molecular mechanism underlying these effects of ApoE4 remains unclear; ApoE alleles could have different influences on Abeta production, extracellular aggregation, or clearance. Because the missense mutations on chromosomes 14 and 21 that cause familial forms of AD appear to lead to increased secretion of Abeta, it is important to determine whether ApoE4 has a similar effect. Here, we have examined the effects of all three ApoE alleles on the processing of betaAPP and the secretion of Abeta in intact cells. We established neural (HS683 human glioma) and non-neural (Chinese hamster ovary) cell culture systems that constitutively secrete both ApoE and Abeta at concentrations like those in human cerebrospinal fluid. betaAPP metabolites, generated in the presence of each ApoE allele, were analysed and quantified by two methods: immunoprecipitation and phosphorimaging, and ELISA. We detected no consistent allele-specific effects of ApoE on betaAPP processing in either cell type. Our data suggest that the higher amyloid burden found in AD subjects expressing ApoE4 is not due to increased amyloidogenic processing of betaAPP, in contrast to findings in AD linked to chromosome 14 or 21. These co-expressing cell lines will be useful in the further search for the effects of ApoE on Abeta aggregation or clearance under physiologically relevant conditions.     

Effect of apolipoprotein E genotype on Alzheimer's disease neuropathology in a cohort of elderly Norwegians

A cohort of elderly Norwegians dying in nursing homes in the Oslo region have been genotyped for the Apolipoprotein E (ApoE) gene. Alzheimer's disease (AD) cortical neuropathology and clinical evidence of dementia were used to assign cases without evidence of other confounding neuropathology. Senile plaque (SP) and neurofibrillary tangle (NFT) densities in frontal, temporal and parietal cortex were then correlated with ApoE genotype to determine any relationship between ApoE genotype and AD pathology. Comparisons with ApoE epsilon 3, epsilon 4 and epsilon 2 allele dosage failed to show any significant effect on cortical SP densities in any cortical area. NFT densities were increased by epsilon 4 allele dosage in the frontal cortex but not in other cortical regions. A reduction was seen in cortical NFT densities with epsilon 2 allele, though again this was not consistently significant in any of the groups. The epsilon 3 allele failed to show any consistent effect on cortical NFT densities. Assessment by individual genotypes showed epsilon 2/3 < epsilon 2/4 < epsilon 3/3 < epsilon 3/4 < epsilon 4/4 which had highest cortical NFT densities in all areas. By genotype, SP densities were generally of the order epsilon 2/4 < epsilon 2/3 < epsilon 3/3 < epsilon 4/4 < epsilon 3/4 though in none of the groups was this significant. Duration of disease showed no consistent effect on neuropathological burden. ApoE genotype may have an effect on determining whether individuals suffer from AD and the age at onset of disease but may only have a minimal effect on pathology burden.     

Costs of cancer research: financial and personal

INTRODUCTION: The HLA-A2 allele has recently been considered as a risk factor in AD by advancing the age at onset of the disease, especially in subjects who were homozygous for the apoE epsilon4 allele. MATERIAL AND METHODS: We examined the distribution of apoE genotypes and A2 allele as a function of age at onset in 109 patients with sporadic and familial AD. RESULTS: In the early onset (< or =60 years) and late onset (>75 years) AD groups, there was, respectively, a 2.2 year and a 2.7 year earlier onset in the A2 positive cases. Age effect was not apparent in the middle onset (61-75 years) AD group. The effect of A2 allele on the age at onset was not different between familial and sporadic AD cases. The presence or absence of the A2 allele did not modify mean age at onset in the groups homozygous and heterozygous for epsilon4, and in cases with no epsilon4 alleles. CONCLUSION: Though the sample size was small, there is a trend in favor of an A2 effect on age at onset. Additionally, there is no evidence of interaction between A2 and apoE epsilon4 alleles on age at onset of AD.     

Apolipoprotein E polymorphism in elderly east Africans

Current advances have shown the apolipoprotein E (APOE)-epsilon 4 allele to be highly associated with late-onset familial and sporadic Alzheimer's disease (AD) in Western populations. The association of APOE allele frequencies and dementia remain unknown in populations from developing countries. We recently initiated a project to examine APOE frequencies in non-demented and demented elderly East Africans. Blood DNA collected from two hospital-based populations showed that the APOE allele frequencies in a group of non-demented 67 Tanzanians over the age of 65 years were found to be 14% for epsilon 2, 61% for epsilon 3 and 25% for epsilon 4. By comparison, the frequency of APOE-epsilon 4 in an age-matched demented group was also 25%. Assessment of APOE genotypes in the group of elderly Kenyan subjects from Nairobi also revealed high frequencies of the epsilon 4 allele with no clear difference in frequency between demented and non-demented subjects. Our preliminary observations suggest that elderly East Africans with no apparent clinical AD possess relatively high APOE-epsilon 4 allele frequencies compared to normal ageing subjects from Western countries including African-Americans. These results appear similar to those reported in a recent study in Nigerian Africans where a lack of correlation between APOE-epsilon 4 allele frequency and Alzheimer type of dementia was noted, and imply that APOE-epsilon 4 allele may not necessarily be a risk factor in some populations of Africa.     

Analysis of the butyrylcholinesterase gene and nearby chromosome 3 markers in Alzheimer disease

The K-variant of butyrylcholinesterase (BCHE-K) recently has been reported to be associated with Alzheimer disease (AD) in carriers of the epsilon4 allele of the apolipoprotein E (APOE) gene. We have re-examined the frequency of the BCHE-K allele in a large data set of both sporadic and familial cases of AD disease, and we have also examined the segregation of three genetic markers on chromosome 3 near BCHE . Our data neither support an association of BCHE-K with sporadic or familial AD, nor do they suggest the existence of another gene nearby on chromosome 3 as a common cause of familial AD.     

Apolipoprotein E epsilon 4 allele distribution in alcoholic dementia and in Alzheimer's disease in Japan

The apolipoprotein E epsilon 4 allele has been associated with both familial and sporadic Alzheimer's disease (AD). Given its possible role in nerve repair and growth, it is plausible that apolipoprotein E may be a common denominator in the pathogenesis of several dementing diseases. Therefore, we investigated epsilon 4 frequencies in demented and nondemented alcoholics, as well as in patients with sporadic AD and controls in Japan. No significant differences in allele frequencies was found between demented and nondemented alcoholics and controls, while a significant association was demonstrated between AD and the epsilon 4 allele. These results support a specific role of epsilon 4 in the pathogenesis of AD, rather than a more general role for epsilon 4 in dementing illnesses.     

Advances in the research on Alzheimer's disease--overview]

The number of patients suffering from dementia in Japan has been estimated to exceed 1,250,000 and is expected to increase rapidly in the near future. It is quickly becoming a serious medical and social issue. Alzheimer's disease (AD) is a leading cause of dementia, and can be classified into two genetic categories: single-gene and polygenic diseases. Familial Alzheimer's disease (FAD) is classified as a single-gene disease, while sporadic AD is classified as a polygenic disease which involves multiple genetic and environmental factors. Using positional cloning, most of the genes which lead to FAD have recently been identified e.g., the amyloid precursor protein (APP) gene on chromosome 21, presenilin I on chromosome 14 and presenilin II on chromosome 1. Recent studies indicate that mutations in these genes can result in either overproduction of A beta or in production of A beta 1-42. Although the accumulation of A beta has been suggested to be the "primary cause" not only in FAD but also in sporadic AD, it remains unclear how neurodegeneration in AD is related to the accumulation of A beta. The discovery of ApoE4 as a major genetic risk factor for AD has created a new step of research on AD as a polygenic disease. Although it is confirmed that the presence of the ApoE4 allele greatly accelerates age at onset of AD, the role of ApoE4 as a risk factor for AD remains to be fully elucidated. Now that major genes involved in the pathogenesis of AD have been identified, future research should be directed toward elucidation of the molecular mechanisms of how these gene products are involved in the pathogenesis of AD on protein as well as cellular levels.     

Apolipoprotein E-associated risk for Alzheimer's disease in the African-American population is genotype dependent

As a part of our ongoing study on Alzheimer's disease (AD) in elderly African Americans, we obtained clinical assessment and apolipoprotein E (ApoE) genotype data on 288 individuals (including 60 with AD). The ApoE epsilon4 allele frequency was significantly increased in AD patients compared with controls. The age-adjusted odds ratio (OR) for AD in epsilon4 homozygotes was 4.83 (95% confidence interval [CI], 1.71-13.64) compared with the epsilon3/epsilon3 genotype, but the OR for AD with the epsilon3/epsilon4 genotype did not reach significance (1.20; 95% CI, 0.58-2.45). These findings suggest that the association between ApoE epsilon4 and AD is weaker in African Americans than in whites.     

Spatiotemporally periodic patterns in symmetrically coupled map lattices

Alzheimer's disease patients have increased frequency of apolipoprotein E allele c4, suggesting apoE4 is a risk factor determining disease. ApoE binds A beta amyloid peptide with great avidity in vitro and in the neuritic plaque. Potentially, binding of A beta to apolipoprotein E could increase A beta neurotoxicity. However, in hippocampal cultures, 0.1 microM apolipoprotein E eliminated the neurotoxicity of 10 microM A beta. Neuronal rescue was dose-dependent and occurred even after 48 hours exposure to A beta, but was overwhelmed by excess A beta. Thus, interaction between these proteins does not directly increase A beta neurotoxicity, and the role of ApoE in Alzheimer's disease remains to be elucidated.     

18O exchange in suspensions of red blood cells: determination of parameters of mass spectrometer inlet system

A variety of anatomic and functional neuroimaging findings are associated with Alzheimer's disease (AD). One of the strongest imaging associations identified is between AD and hippocampal atrophy. The epsilon4 allele of the apolipoprotein E (ApoE) gene increases the risk of developing AD and lowers the mean age of onset of the disease. The purpose of this study was to assess the association between hippocampal volume and ApoE polymorphisms in elderly control subjects and in patients with probable AD. We performed magnetic resonance imaging-based volume measurements of the hippocampus in 125 cognitively normal elderly controls and 62 patients with probable AD. ApoE genotyping was performed by using standard methods. Hippocampal volumes were significantly smaller in AD cases than in control subjects. Hippocampal volumes did not differ significantly within either clinical group on the basis of ApoE genotype. Both the epsilon4 allele of ApoE and hippocampal atrophy were significantly but independently associated with AD.     

The apolipoprotein E allele epsilon 4 is overrepresented in patients with the Lewy body variant of Alzheimer's disease

We determined apolipoprotein E (ApoE) genotypes in 122 autopsied demented patients. The frequency of the ApoE epsilon 4 allele was 39.6% in Alzheimer's disease (AD), 29.0% in the Lewy body variant of AD (LBV), and 6.25% in diffuse Lewy body disease. For AD and LBV patients, the epsilon 4 frequency was significantly higher than that reported in nondemented controls (10 to 15%). Therefore, LBV and AD share ApoE epsilon 4 as a genetic risk factor, providing further evidence that these conditions overlap.     

Abundance of the longer A beta 42 in neocortical and cerebrovascular amyloid beta deposits in Swedish familial Alzheimer's disease and Down's syndrome

Recent studies have demonstrated the deposition of amyloid beta (A beta) protein with carboxyl- and aminoterminal heterogeneity in cortical and cerebrovascular deposits of Alzheimer's disease (AD). Using carboxyl end-terminal specific antibodies to A beta peptides, we examined the immunocytochemical distribution of A beta 40 and A beta 42 species in brain tissue from a Swedish subject with familial AD (FAD) bearing the double mutation at codons 670/671 in the amyloid beta precursor protein (A beta PP), and from subjects with Down's syndrome and sporadic AD. In the Swedish subject, we found profound parenchymal A beta deposits and cerebral amyloid angiopathy in all four cortical lobes and cerebellum. A beta 42 was evident in almost all parenchymal deposits as well as many vascular deposits. Although A beta 40 was present in meningeal and intraparenchymal vessels, deposits containing this shorter peptide reactivity were sparse. Surprisingly, our observations in Swedish FAD showing a remarkable abundance of A beta 42 in both parenchymal and vascular deposits were qualitatively similar to the Down's syndrome and most sporadic AD cases, and to previously published A beta PP717 FAD. While previous transfection studies in different cell cultures indicate substantially increased soluble A beta production and A beta 40 species to be predominant, it would appear that the double A beta PP mutations in Swedish FAD largely result in the deposition of the longer A beta 42 in vivo.     

Progress of the molecular genetic analysis for Alzheimer's disease

The pathogenesis of Alzheimer's disease (AD) remains unclear. We ascertained 57 Japanese families with early onset familial Alzheimer's disease (EOFAD; mean onset age < 65 years). Screening the known beta/A4 amyloid precursor protein (APP) mutations in familial AD by a simplified PCR product detection system disclosed only one EOFAD with the APP717Val-Ile mutation (AD1 locus). Four of 6 families showing a positive linkage to AD3 locus had four different mutations on the presenilin 1 gene. These mutations were Val 96 Phe, Ile223Thr, His163Arg and splicing mutation with an AG-AA substitution at the acceptor site of intron 9. The allele frequency of APOE-e4 of late-onset and early-onset AD was significantly higher than that of age-matched controls (p < 0.0001). These results suggest that APOE-e4 (AD2 locus) is a susceptibility gene for AD in the Japanese population, regardless of the age at onset. It is probable that the risk for AD in most subjects is likely to arise from the cumulative effects of environmental factors along with various genetic factors. Advances in molecular biology and molecular genetics have enabled us to more easily understand these genetic factors.     

Alzheimer's disease: interaction of apolipoprotein E genotype, family history of dementia, gender, education, ethnicity, and age of onset

We evaluated 197 patients with predominantly late-onset Alzheimer's disease (AD) who belonged to several ethnic groups and analyzed the relationship of age of onset of AD to the presence or absence of several risk factors in this entire group of patients. The apolipoprotein E (apoE) epsilon 4 allele frequency, which was 29% in all patients (compared with the reported population mean of 13.7%, p < 0.001, did not vary significantly between ethnic groups but declined significantly with increasing age. The apoE epsilon 2 allele frequency was 3%, compared with the reported population mean of 7.4% (p = 0.001). The frequency of a positive family history of dementia in first-degree relatives (FH +) (overall 45%) did not vary significantly between ethnic groups. ApoE epsilon 4-positive (epsilon 4+) patients tended to have a higher FH + rate (58%) than apoE epsilon 4-negative (epsilon 4-) patients (40%) (p = 0.02). When the potential risk factors of gender, education, FH+ status, and epsilon 4+ status were examined together in a multiple linear-regression analysis, FH+ and epsilon 4+ status (but not gender or education) were significant (they were both associated with an earlier age of onset of AD). In a post-hoc analysis, we found a reduced age of onset in women, but not men, who were both FH + and epsilon 4+. Additionally, those probands who were epsilon 4+ were more likely to inherit the disease from their mothers than their fathers. The mechanism by which epsilon 4+ and FH+ status operate as risk factors may be by their effect on the age of onset of AD.     

Real-time NMR studies on folding of mutants of barnase and chymotrypsin inhibitor 2

Apolipoprotein E (apo E) epsilon4 is a risk factor for sporadic and late-onset familial Alzheimer's disease, but it is not well known whether the apo E is associated with spinocerebellar degeneration. We studied the frequency of apo E allele in 59 olivopontocerebellar atrophy (OPCA) patients, including 13 pathologically confirmed cases. The distribution of the apo E allele frequency did not differ between OPCA patients and controls. Apo E allele does not influence the development of OPCA.     

No association between the low density lipoprotein receptor-related protein (LRP) gene and late-onset Alzheimer's disease in a community-based sample

It is now commonly known that possession of the epsilon4 allele of the apolipoprotein E (APOE) gene confers an increased risk for both familial and sporadic Alzheimer's disease (AD), in a dose-dependent way. Other genes that may play a role in AD, either through independent association with the disease or through modification of the existing APOE risk, have been reported with conflicting results. One such gene, the low density lipoprotein receptor-related protein (LRP) gene, was recently reported by two groups to be associated with AD, although the groups identified different risk-conferring alleles. Both studies were based on clinic-derived AD populations (one American, one French), and both reported only marginally significant results. We have genotyped a community-based AD and control population at this LRP polymorphism and find no association between the variants at that polymorphism and the occurrence of AD. Further, despite the biochemical relationship between LRP and the ApoE protein, we find no significant statistical interaction between the alleles at these loci.