| 1. |
- de la Vega, Maria Pagnon, et al.
(author)
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The Uppsala APP deletion causes early onset autosomal dominant Alzheimer's disease by altering APP processing and increasing amyloid beta fibril formation
- 2021
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In: Science Translational Medicine. - : American Association for the Advancement of Science (AAAS). - 1946-6234 .- 1946-6242. ; 13:606
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Journal article (peer-reviewed)abstract
- Point mutations in the amyloid precursor protein gene (APP) cause familial Alzheimer's disease (AD) by increasing generation or altering conformation of amyloid beta (A beta). Here, we describe the Uppsala APP mutation (Delta 690-695), the first reported deletion causing autosomal dominant AD. Affected individuals have an age at symptom onset in their early forties and suffer from a rapidly progressing disease course. Symptoms and biomarkers are typical of AD, with the exception of normal cerebrospinal fluid (CSF) A beta 42 and only slightly pathological amyloid-positron emission tomography signals. Mass spectrometry and Western blot analyses of patient CSF and media from experimental cell cultures indicate that the Uppsala APP mutation alters APP processing by increasing beta-secretase cleavage and affecting alpha-secretase cleavage. Furthermore, in vitro aggregation studies and analyses of patient brain tissue samples indicate that the longer form of mutated A beta, A beta Upp1-42(Delta 19-24), accelerates the formation of fibrils with unique polymorphs and their deposition into amyloid plaques in the affected brain.
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| 2. |
- Degerman Gunnarsson, Malin, 1969-
(author)
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Biomarkers as Monitors of Drug Effect, Diagnostic Tools and Predictors of Deterioration Rate in Alzheimer’s Disease
- 2013
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Doctoral thesis (other academic/artistic)abstract
- Decreased amyloid-ß42 (Aß42), increased total tau (t-tau) and phosphorylated tau (p-tau) in cerebrospinal fluid (CSF) reflect histopathological core changes in the most common dementia disorder, Alzheimer’s disease (AD). They discriminate AD from healthy controls and predict conversion to AD with a relatively high accuracy. Memantine, an uncompetitive NMDA-receptor antagonist, is indicated for symptomatic treatment of AD. The first aim of this thesis was to investigate effects of memantine on CSF concentrations of Aβ42, tau and p-tau. Secondly, the aim was to explore the relation between these CSF biomarkers and retention of the amyloid biomarker Pittsburgh compound B using positron emission tomography (PIB PET), regional glucose metabolism measured with 18Fluoro-2-deoxy-d-glucose (FDG) PET and neuropsychological test performance. The third aim was to investigate their possible utility as predictors of future rate of AD dementia deterioration. All patients in the studies were recruited from the Memory Clinic, Uppsala University Hospital. In study I CSF p-tau concentrations in 11 AD patients were reduced after twelve months treatment with memantine, indicating that this compound may affect a key pathological process in AD. Results from study II showed that the concentrations of CSF Aß42 are lower in PIB+ patients than in PIB- patients, and that the PIB retention was stable during 12 months. In study III 10 patients with the diagnoses AD (6 PIB+/4 PIB-) and 8 subjects (1 PIB+/7 PIB-) with frontotemporal dementia were included. PIB+ patients had lower psychomotor speed measured by performance on the Trail Making Test A and impaired visual episodic memory compared to the PIB- patients. The initial clinical diagnoses were changed in 33% of the patients (6/18) during follow-up. Study IV is the first-ever report of an association between high CSF tau and dying in severe dementia. These 196 AD patients were followed up to nine years after baseline lumbar puncture. Moreover, CSF t-tau concentrations above median was associated with an increased risk of rapid cognitive decline (OR 3.31 (95% CI 1.53-7.16), independently of baseline functional stage. Thus, a clear association between high levels of CSF t-tau and p-tau and a more aggressive course of the disease was shown.
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| 3. |
- Degerman Gunnarsson, Malin, et al.
(author)
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High Tau Levels in Cerebrospinal Fluid Predict Rapid Decline and Increased Dementia Mortality in Alzheimer's Disease
- 2014
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In: Dementia and Geriatric Cognitive Disorders. - : S. Karger AG. - 1420-8008 .- 1421-9824. ; 37:3-4, s. 196-206
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Journal article (peer-reviewed)abstract
- Objective: Cerebrospinal fluid (CSF) amyloid beta(42) (A beta(42)), total tau (t-tau) and phosphorylated tau (p-tau) are useful as predictors of conversion from mild cognitive impairment (MCI) to Alzheimer's disease (AD) dementia. However, results are contradictory as to whether these biomarkers reflect the future rate of clinical decline. Methods: This is a retrospective study on 196 patients with AD [mild/moderate AD (n = 72) or AD-MCI (n = 124) at baseline] with a follow-up period of 2-9 years' duration (median 6 years). Lumbar punctures were performed at baseline as a part of the diagnostic procedure. Results: We found an increased risk of rapid cognitive decline defined as a drop in the Mini-Mental State Examination score of = 4 points/year in patients with CSF t-tau concentrations above the median (OR 3.31, 95% CI 1.53-7.16) and CSF p-tau above the median (OR 2.53, 95% CI 1.21-5.26). Patients with CSF t-tau in the highest quartile had a higher risk of dying in severe dementia (HR 4.67, 95% CI 1.16-18.82). Conclusions: In this large AD cohort, we found an association between high levels of CSF t-tau and p-tau and a more aggressive course of the disease, measured as a rapid cognitive decline and a higher risk of dying in severe dementia.
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| 4. |
- Degerman Gunnarsson, Malin, et al.
(author)
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Pittsburgh compound-B and Alzheimer's disease biomarkers in CSF, plasma and urine: An exploratory study.
- 2010
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In: Dementia and geriatric cognitive disorders. - Basel : S. Karger AG. - 1421-9824 .- 1420-8008. ; 29:3, s. 204-12
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Journal article (peer-reviewed)abstract
- BACKGROUND: The positron emission tomography (PET) radiotracer Pittsburgh Compound-B (PIB) is an in vivo ligand for measuring beta-amyloid (Abeta) load. Associations between PET PIB and cerebrospinal fluid (CSF) Abeta1-42 and apolipoprotein E epsilon4 (APOE epsilon4) have been observed in several studies, but the relations between PIB uptake and other biomarkers of Alzheimer's disease (AD) are less investigated. METHOD: PET PIB, PET 18Fluoro-2-deoxy-D-glucose and different AD biomarkers were measured twice in CSF, plasma and urine 12 months apart in 10 patients with a clinical diagnosis of mild to moderate AD. RESULTS: PIB retention was constant over 1 year, inversely related to low CSF Abeta1-42 (p = 0.01) and correlated positively to the numbers of the APOE epsilon4 allele (0, 1 or 2) (p = 0.02). There was a relation between mean PIB retention and CSF ApoE protein (r = -0.59, p = 0.07), and plasma cystatin C (r = -0.56, p = 0.09). CONCLUSION: PIB retention is strongly related to CSF Abeta1-42, and to the numbers of the APOE epsilon4 allele.
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| 5. |
- Degerman Gunnarsson, Malin, et al.
(author)
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Re-evaluation of clinical dementia diagnoses with PET-PIB
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Other publication (other academic/artistic)abstract
- Objectives: There is an overlap regarding Pittsburgh Compound-B (PIB) retention in patients clinically diagnosed as Alzheimer’s disease (AD) and non-AD dementia. The aim of the present study was to investigate whether there are any differences between PIB+ and PIB PIB- patients in a mixed cohort of patients with neurodegenerative dementia of mild severity regarding neuropsychological test performance and regional cerebral glucose metabolism measured with 18 Fluoro-2-deoxy-d-glucose (FDG) PET.Methods: Eighteen patients clinically diagnosed as probable AD or frontotemporal dementia were examined with PIB PET, FDG PET and neuropsychological tests and followed for 5-9 years in a clinical setting.Results: The PIB+ patients (7/18) had slower psychomotor speed and more impaired visual episodic memory than the PIB- patients, otherwise performance did not differ between groups. The initial clinical diagnoses were changed in one third of the patients (6/18) during follow-up. Conclusions: The subtle differences in neuropsychological performance, the overlap of hypometabolic patterns and clinical features between AD and non-AD dementia highlight the need of amyloid biomarkers and readiness to re-evaluate the initial diagnosis.
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| 6. |
- Degerman Gunnarsson, Malin, et al.
(author)
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Re-Evaluation of Clinical Dementia Diagnoses with Pittsburgh Compound B Positron Emission Tomography
- 2013
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In: Dementia and Geriatric Cognitive Disorders Extra. - Basel : S. Karger. - 1664-5464. ; 3:1, s. 472-481
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Journal article (peer-reviewed)abstract
- Objectives: There is an overlap regarding Pittsburgh compound B (PIB) retention in patients clinically diagnosed as Alzheimer's disease (AD) and non-AD dementia. The aim of the present study was to investigate whether there are any differences between PIB-positive and PIB-negative patients in a mixed cohort of patients with neurodegenerative dementia of mild severity regarding neuropsychological test performance and regional cerebral glucose metabolism measured with [18F]fluoro-2-deoxy-d-glucose (FDG) positron emission tomography (PET). Methods: Eighteen patients clinically diagnosed as probable AD or frontotemporal dementia were examined with PIB PET, FDG PET and neuropsychological tests and followed for 5-9 years in a clinical setting. Results: The PIB-positive patients (7 out of 18) had slower psychomotor speed and more impaired visual episodic memory than the PIB-negative patients; otherwise performance did not differ between the groups. The initial clinical diagnoses were changed in one third of the patients (6 out of 18) during follow-up. Conclusions: The subtle differences in neuropsychological performance, the overlap of hypometabolic patterns and clinical features between AD and non-AD dementia highlight the need for amyloid biomarkers and a readiness to re-evaluate the initial diagnosis.
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| 7. |
- Degerman Gunnarsson, Malin, et al.
(author)
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Reduction of Phosphorylated Tau during Memantine Treatment of Alzheimer's Disease
- 2007
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In: Dementia and Geriatric Cognitive Disorders. - : S. Karger AG. - 1420-8008 .- 1421-9824. ; 24:4, s. 247-252
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Journal article (peer-reviewed)abstract
- Background: Memantine is a moderate affinity N-methyl-D-aspartate receptor antagonist approved for treatment of Alzheimer's disease (AD). In AD, tau is abnormally hyperphosphorylated. However, no significant changes of phosphorylated tau levels in CSF are found at follow-up in studies with AD patients. It has been shown in vitro that memantine reverse induced abnormal hyperphosphorylation of tau in hippocampal neurons of rats. Methods: Eleven AD patients were examined with cognitive tests and interviews of relatives. CSF analyses were performed before starting treatment with memantine as well as after 1 year. Results: A statistically significant reduction of CSF phosphorylated tau at the 1-year follow-up was seen, from median 126 (interquartile range 107-153) to 108 (88-133) ng/l (p = 0.018). No statistically significant differences of total tau or A42 were found. Conclusion: The results may reflect effects of memantine on a key pathological feature in AD in line with previous in vitro findings.
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| 8. |
- Emami Khoonsari, Payam, et al.
(author)
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Chitinase-3-like protein 1 (CH3L1) and Neurosecretory protein VGF (VGF) as two novel CSF biomarker candidates for improved diagnostics in Alzheimer’s disease
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Other publication (other academic/artistic)abstract
- Alzheimer’s disease (AD) is a chronic neurodegenerative disorder characterized by amyloid-β (Aβ) plaque deposition and accumulation of intracellular neurofibrillary tangles. This pathology is mirrored in the cerebrospinal fluid (CSF), where decreased Aβ42 together with increased total (t-tau) and phospho-tau (p-tau) today is used as a diagnostic marker. Although these biomarkers have a fairly good sensitivity and specificity, additional biomarkers are needed to further improve the accuracy for early disease detection and to monitor disease development. In this study, we used mass spectrometry-based shotgun proteomics to investigate the CSF proteome of patients with AD and mild cognitive impairment (MCI) as well as of non-demented controls. By combining the diagnostic markers (Aβ42, total t-tau, and p-tau) with a selection of proteomics biomarkers, the accuracy of predicting MCI to AD conversion increased from 83% to 92% with a specificity of 1.0 and sensitivity of 0.86. Among these markers, the levels of protein chitinase-3-like protein 1 (CH3L1) were significantly higher in AD and MCI converters compared to controls. In addition to Aβ42, t-tau, and p-tau the protein CH3L1 contributed mostly to the prediction accuracy. We also found statistically significant lower CSF levels of the neurosecretory protein VGF (VGF) in AD compared to controls. Taken together, our findings suggest that incorporating new CSF biomarkers can further enhance early diagnosis of AD.
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| 9. |
- Emami Khoonsari, Payam, et al.
(author)
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Improved Differential Diagnosis of Alzheimer's Disease by Integrating ELISA and Mass Spectrometry-Based Cerebrospinal Fluid Biomarkers
- 2019
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In: Journal of Alzheimer's Disease. - : IOS PRESS. - 1387-2877 .- 1875-8908. ; 67:2, s. 639-651
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Journal article (peer-reviewed)abstract
- Background: Alzheimer's disease (AD) is diagnosed based on a clinical evaluation as well as analyses of classical biomarkers: A beta(42), total tau (t-tau), and phosphorylated tau (p-tau) in cerebrospinal fluid (CSF). Although the sensitivities and specificities of the classical biomarkers are fairly good for detection of AD, there is still a need to develop novel biochemical markers for early detection of AD. Objective: We explored if integration of novel proteins with classical biomarkers in CSF can better discriminate AD from non-AD subjects. Methods: We applied ELISA, mass spectrometry, and multivariate modeling to investigate classical biomarkers and the CSF proteome in subjects (n = 206) with 76 AD patients, 74 mild cognitive impairment (MCI) patients, 11 frontotemporal dementia (FTD) patients, and 45 non-dementia controls. The MCI patients were followed for 4-9 years and 21 of these converted to AD, whereas 53 remained stable. Results: By combining classical CSF biomarkers with twelve novel markers, the area of the ROC curves (AUROCS) of distinguishing AD and MCl/AD converters from non-AD were 93% and 96%, respectively. The FTDs and non-dementia controls were identified versus all other groups with AUROCS of 96% and 87%, respectively. Conclusions: Integration of new and classical CSF biomarkers in a model-based approach can improve the identification of AD, FTD, and non-dementia control subjects.
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| 10. |
- Englund, Hillevi, 1980-, et al.
(author)
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Oligomerization partially explains the lowering of Aβ42 in Alzheimer's disease cerebrospinal fluid
- 2009
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In: Neuro-degenerative diseases. - : S. Karger AG. - 1660-2862 .- 1660-2854. ; 6:4, s. 139-147
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Journal article (peer-reviewed)abstract
- Background/aim: The lowering of natively analyzed Aβ42 in cerebrospinal fluid (CSF) is used as a diagnostic tool in Alzheimer’s disease (AD). Presence of Aβ oligomers can interfere with such analyses causing underestimation of Aβ levels due to epitope masking. The aim was to investigate if the lowering of CSF Aβ42 seen is caused by oligomerization. Methods: Aβ42 was analyzed under both denaturing and non-denaturing conditions. An Aβ42 oligomer ratio was calculated from these quantifications. Presence of oligomers leads to Aβ42 epitope masking during non-denaturing assays, resulting in a higher ratio. Results: The Aβ42 oligomer ratio was used for assessment of oligomerized Aβ in human CSF, after being evaluated in transgenic mouse brain homogenates. AD and mild cognitive impairment (MCI) samples displayed the expected decrease in natively measured Aβ42 compared to healthy controls and frontotemporal dementia, but not when analyzing under denaturing conditions. Accordingly, AD and MCI CSF had a higher Aβ42 oligomer ratio in CSF. Conclusion: Combining denaturing and non-denaturing quantifications of Aβ42 into an oligomer ratio enables assessment of Aβ oligomers in biological samples. The increased Aβ42 oligomer ratio for AD and MCI indicates presence of oligomers in CSF and that the lowering of natively measured Aβ42 is caused by oligomerization.
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