| 1. |
- Andersson, Carl-Henrik, et al.
(author)
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A Genetic Variant of the Sortilin 1 Gene is Associated with Reduced Risk of Alzheimer's Disease
- 2016
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In: Journal of Alzheimer's Disease. - 1387-2877 .- 1875-8908. ; 53:4, s. 1353-1363
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Journal article (peer-reviewed)abstract
- Alzheimer's disease (AD) is a neurodegenerative disorder represented by the accumulation of intracellular tau protein and extracellular deposits of amyloid-β (Aβ) in the brain. The gene sortilin 1 (SORT1) has previously been associated with cardiovascular disease in gene association studies. It has also been proposed to be involved in AD pathogenesis through facilitating Aβ clearance by binding apoE/Aβ complexes prior to cellular uptake. However, the neuropathological role of SORT1 in AD is not fully understood. To evaluate the associations between gene variants of SORT1 and risk of AD, we performed genetic analyses in a Swedish case-control cohort. Ten single nucleotide polymorphisms (SNPs), covering the whole SORT1 gene, were selected and genotyped in 620 AD patients and 1107 controls. The SNP rs17646665, located in a non-coding region of the SORT1 gene, remained significantly associated with decreased risk of AD after multiple testing (pc = 0.0061). In addition, other SNPs were found to be nominally associated with risk of AD, as well as altered cognitive function and the CSF biomarker Aβ42, but these associations did not survive correction for multiple testing. The fact that SORT1 has been strongly associated with risk of cardiovascular disease is intriguing as cardiovascular disease is also regarded as a risk factor for AD. Finally, increased knowledge about SORT1 function has a potential to increase our understanding of APOE, the strongest risk factor for AD.
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| 2. |
- Andersson, Malin E, 1978, et al.
(author)
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Kinesin gene variability may affect tau phosphorylation in early Alzheimer's disease.
- 2007
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In: International journal of molecular medicine. - 1107-3756 .- 1791-244X. ; 20:2, s. 233-9
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Journal article (peer-reviewed)abstract
- Kinesin is a microtubule-associated motor protein that transports Alzheimer-associated amyloid precursor protein (APP) in neurons. In animal models, impaired kinesin-mediated APP transport seems to enhance formation of the neurotoxic 42 amino acid fragment of beta-amyloid (A beta 42). In man, one study suggests that a polymorphism (rs8702, 56,836G>C) in the kinesin light chain 1 gene (KNS2) may affect the risk of Alzheimer's disease (AD). To further assess KNS2 as a susceptibility gene for AD we analyzed 802 patients with sporadic AD and 286 controls, 134 longitudinally followed patients with mild cognitive impairment (MCI) and 39 cognitively stable controls for the rs8702 polymorphism. The rs8702 polymorphism did not influence risk of AD (p=0.46). However, rs8702 interacted with APOE epsilon 4 carrier status in AD (p=0.006) and influenced cerebrospinal fluid levels of hyperphosphorylated tau in MCI patients who converted to AD during follow-up (p=0.018). These findings support earlier indications that genetic variability in the KNS2 gene may play a role during early stages of AD pathogenesis.
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| 3. |
- Blennow, Kaj, 1958, et al.
(author)
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No association between the alpha2-macroglobulin (A2M) deletion and Alzheimer's disease, and no change in A2M mRNA, protein, or protein expression.
- 2000
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In: Journal of neural transmission (Vienna, Austria : 1996). - : Springer Science and Business Media LLC. - 0300-9564 .- 1435-1463. ; 107:8-9, s. 1065-79
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Journal article (peer-reviewed)abstract
- A polymorphism consisting of a deletion near the 5' splice site of exon 18 on the alpha2-macroglobulin (A2M) gene (A2M-2) has been suggested to be associated with Alzheimer's disease (AD) in family-based studies. We studied the A2M-2 allele together with the ApoE alleles in a large series on patients with AD (n = 449) and age-matched controls (n = 349). Neuropathologically confirmed diagnoses were available in 199 cases (94 AD and 107 control cases). We found no increase in A2M-2 genotype or allele frequencies in AD (27.5% and 14.6%) versus controls (26.4% and 14.9%). In contrast, a marked increase (p < 0.0001) in ApoE epsilon4 genotype or allele frequencies was found in AD (66.6% and 41.2%) as compared with controls (29.8% and 16.5%), suggesting sufficient statistical power in our sample. No relation was found between the A2M-2 and the ApoE epsilon4 allele. No change in A2M exon 17-18 mRNA size or sequence or A2M protein size was found in cases carrying the A2M-2 deletion, suggesting that there is no biological consequences of the A2M intronic deletion. No change in A2M protein level in cerebrospinal fluid was found in AD, suggesting that the A2M-2 allele does not effect the A2M protein expression in the brain. The lack of an association between the A2M-2 allele and AD in the present study, and the lack of abnormalities in the A2M mRNA or protein suggest that the A2M-2 allele is not associated with AD.
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| 4. |
- Brinkmalm-Westman, Ann, 1966, et al.
(author)
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SNAP-25 is a promising novel cerebrospinal fluid biomarker for synapse degeneration in Alzheimer's disease
- 2014
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In: Molecular Neurodegeneration. - : Springer Science and Business Media LLC. - 1750-1326. ; 9
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Journal article (peer-reviewed)abstract
- Background: Synaptic degeneration is an early pathogenic event in Alzheimer's disease, associated with cognitive impairment and disease progression. Cerebrospinal fluid biomarkers reflecting synaptic integrity would be highly valuable tools to monitor synaptic degeneration directly in patients. We previously showed that synaptic proteins such as synaptotagmin and synaptosomal-associated protein 25 (SNAP-25) could be detected in pooled samples of cerebrospinal fluid, however these assays were not sensitive enough for individual samples. Results: We report a new strategy to study synaptic pathology by using affinity purification and mass spectrometry to measure the levels of the presynaptic protein SNAP-25 in cerebrospinal fluid. By applying this novel affinity mass spectrometry strategy on three separate cohorts of patients, the value of SNAP-25 as a cerebrospinal fluid biomarker for synaptic integrity in Alzheimer's disease was assessed for the first time. We found significantly higher levels of cerebrospinal fluid SNAP-25 fragments in Alzheimer's disease, even in the very early stages, in three separate cohorts. Cerebrospinal fluid SNAP-25 differentiated Alzheimer's disease from controls with area under the curve of 0.901 (P < 0.0001). Conclusions: We developed a sensitive method to analyze SNAP-25 levels in individual CSF samples that to our knowledge was not possible previously. Our results support the notion that synaptic biomarkers may be important tools for early diagnosis, assessment of disease progression, and to monitor drug effects in treatment trials.
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| 5. |
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| 6. |
- Duits, Flora H., et al.
(author)
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The cerebrospinal fluid "Alzheimer profile": Easily said, but what does it mean?
- 2014
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In: Alzheimer's & Dementia. - : Elsevier. - 1552-5260 .- 1552-5279. ; 10:6, s. 713-723
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Journal article (peer-reviewed)abstract
- Background: We aimed to identify the most useful definition of the "cerebrospinal fluid Alzheimer profile," based on amyloid-beta(1-42) (A beta(42)), total tau, and phosphorylated tau (p-tau), for diagnosis and prognosis of Alzheimers disease (AD). Methods: We constructed eight Alzheimer profiles with previously published combinations, including regression formulas and simple ratios. We compared their diagnostic accuracy and ability to predict dementia due to AD in 1385 patients from the Amsterdam Dementia Cohort. Results were validated in an independent cohort (n = 1442). Results: Combinations outperformed individual biomarkers. Based on the sensitivity of the best performing regression formulas, cutoffs were chosen at 0.52 for the tau/A beta(42) ratio and 0.08 for the p-tau/A beta(42) ratio. Ratios performed similar to formulas (sensitivity, 91%-93%; specificity, 81%-84%). The same combinations best predicted cognitive decline in mild cognitive impairment patients. Validation confirmed these results, especially regarding the tau/A beta(42) ratio. Conclusions: A tau/A beta(42) ratio of greater than0.52 constitutes a robust cerebrospinal fluid Alzheimer profile. We recommend using this ratio to combine biomarkers.
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| 7. |
- Hansson, Oskar, et al.
(author)
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Evaluation of plasma Abeta(40) and Abeta(42) as predictors of conversion to Alzheimer's disease in patients with mild cognitive impairment.
- 2010
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In: Neurobiology of aging. - : Elsevier BV. - 1558-1497 .- 0197-4580. ; 31:3, s. 357-67
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Journal article (peer-reviewed)abstract
- Numerous studies have shown a marked decrease of beta-amyloid(42) (Abeta(42)) in the cerebrospinal fluid (CSF) of patients with incipient Alzheimer's disease (AD). However, studies on Abeta in plasma are contradictory, and show very marginal differences between patients and controls. Here, we analyzed plasma samples using a new multiplex immunoassay for simultaneous analysis of Abeta(1-40), Abeta(n-40), Abeta(1-42), and Abeta(n-42). The plasma samples were obtained at baseline from two independent cohorts of patients with mild cognitive impairment (MCI) and age-matched controls. In the first cohort, 41% of the 117 MCI cases converted to AD during a clinical follow-up period of 4-7 years. In the second cohort, 14% of the 110 MCI subjects developed AD during a clinical follow-up period of 2-4 years. None of the plasma Abeta isoforms differed between MCI patients that subsequently developed AD and healthy controls or stable MCI patients. The Cox proportional hazards model did not reveal any differences in the probability of progression from MCI to AD related to plasma Abeta levels. In contrast, low levels of Abeta(1-42) in CSF were strongly associated with increased risk of future AD. The absence of a change in plasma Abeta in incipient AD, despite the marked change in CSF, may be explained by the lack of a correlation between the levels of Abeta(1-42) in CSF and plasma. In conclusion, the results show that CSF biomarkers are better predictors of progression to AD than plasma Abeta isoforms.
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| 8. |
- Jansen, Willemijn J, et al.
(author)
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Association of Cerebral Amyloid-β Aggregation With Cognitive Functioning in Persons Without Dementia.
- 2018
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In: JAMA psychiatry. - : American Medical Association (AMA). - 2168-6238 .- 2168-622X. ; 75:1, s. 84-95
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Journal article (peer-reviewed)abstract
- Cerebral amyloid-β aggregation is an early event in Alzheimer disease (AD). Understanding the association between amyloid aggregation and cognitive manifestation in persons without dementia is important for a better understanding of the course of AD and for the design of prevention trials.To investigate whether amyloid-β aggregation is associated with cognitive functioning in persons without dementia.This cross-sectional study included 2908 participants with normal cognition and 4133 with mild cognitive impairment (MCI) from 53 studies in the multicenter Amyloid Biomarker Study. Normal cognition was defined as having no cognitive concerns for which medical help was sought and scores within the normal range on cognitive tests. Mild cognitive impairment was diagnosed according to published criteria. Study inclusion began in 2013 and is ongoing. Data analysis was performed in January 2017.Global cognitive performance as assessed by the Mini-Mental State Examination (MMSE) and episodic memory performance as assessed by a verbal word learning test. Amyloid aggregation was measured with positron emission tomography or cerebrospinal fluid biomarkers and dichotomized as negative (normal) or positive (abnormal) according to study-specific cutoffs. Generalized estimating equations were used to examine the association between amyloid aggregation and low cognitive scores (MMSE score ≤27 or memory z score≤-1.28) and to assess whether this association was moderated by age, sex, educational level, or apolipoprotein E genotype.Among 2908 persons with normal cognition (mean [SD] age, 67.4 [12.8] years), amyloid positivity was associated with low memory scores after age 70 years (mean difference in amyloid positive vs negative, 4% [95% CI, 0%-7%] at 72 years and 21% [95% CI, 10%-33%] at 90 years) but was not associated with low MMSE scores (mean difference, 3% [95% CI, -1% to 6%], P = .16). Among 4133 patients with MCI (mean [SD] age, 70.2 [8.5] years), amyloid positivity was associated with low memory (mean difference, 16% [95% CI, 12%-20%], P < .001) and low MMSE (mean difference, 14% [95% CI, 12%-17%], P < .001) scores, and this association decreased with age. Low cognitive scores had limited utility for screening of amyloid positivity in persons with normal cognition and those with MCI. In persons with normal cognition, the age-related increase in low memory score paralleled the age-related increase in amyloid positivity with an intervening period of 10 to 15 years.Although low memory scores are an early marker of amyloid positivity, their value as a screening measure for early AD among persons without dementia is limited.
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| 9. |
- Jansen, Willemijn J, et al.
(author)
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Prevalence of cerebral amyloid pathology in persons without dementia: a meta-analysis.
- 2015
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In: JAMA. - : American Medical Association (AMA). - 1538-3598 .- 0098-7484. ; 313:19, s. 1924-38
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Journal article (peer-reviewed)abstract
- Cerebral amyloid-β aggregation is an early pathological event in Alzheimer disease (AD), starting decades before dementia onset. Estimates of the prevalence of amyloid pathology in persons without dementia are needed to understand the development of AD and to design prevention studies.
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| 10. |
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