| 1. |
- Allentoft, Morten E., et al.
(författare)
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Population genomics of post-glacial western Eurasia
- 2024
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Ingår i: Nature. - 0028-0836 .- 1476-4687. ; 625:7994, s. 301-311
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Tidskriftsartikel (refereegranskat)abstract
- Western Eurasia witnessed several large-scale human migrations during the Holocene1–5. Here, to investigate the cross-continental effects of these migrations, we shotgun-sequenced 317 genomes—mainly from the Mesolithic and Neolithic periods—from across northern and western Eurasia. These were imputed alongside published data to obtain diploid genotypes from more than 1,600 ancient humans. Our analyses revealed a ‘great divide’ genomic boundary extending from the Black Sea to the Baltic. Mesolithic hunter-gatherers were highly genetically differentiated east and west of this zone, and the effect of the neolithization was equally disparate. Large-scale ancestry shifts occurred in the west as farming was introduced, including near-total replacement of hunter-gatherers in many areas, whereas no substantial ancestry shifts happened east of the zone during the same period. Similarly, relatedness decreased in the west from the Neolithic transition onwards, whereas, east of the Urals, relatedness remained high until around 4,000 bp, consistent with the persistence of localized groups of hunter-gatherers. The boundary dissolved when Yamnaya-related ancestry spread across western Eurasia around 5,000 bp, resulting in a second major turnover that reached most parts of Europe within a 1,000-year span. The genetic origin and fate of the Yamnaya have remained elusive, but we show that hunter-gatherers from the Middle Don region contributed ancestry to them. Yamnaya groups later admixed with individuals associated with the Globular Amphora culture before expanding into Europe. Similar turnovers occurred in western Siberia, where we report new genomic data from a ‘Neolithic steppe’ cline spanning the Siberian forest steppe to Lake Baikal. These prehistoric migrations had profound and lasting effects on the genetic diversity of Eurasian populations.
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| 2. |
- Allentoft, Morten E., et al.
(författare)
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100 ancient genomes show repeated population turnovers in Neolithic Denmark
- 2024
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Ingår i: Nature. - 0028-0836 .- 1476-4687. ; 625, s. 329-337
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Tidskriftsartikel (refereegranskat)abstract
- Major migration events in Holocene Eurasia have been characterized genetically at broad regional scales1–4. However, insights into the population dynamics in the contact zones are hampered by a lack of ancient genomic data sampled at high spatiotemporal resolution5–7. Here, to address this, we analysed shotgun-sequenced genomes from 100 skeletons spanning 7,300 years of the Mesolithic period, Neolithic period and Early Bronze Age in Denmark and integrated these with proxies for diet (13C and 15N content), mobility (87Sr/86Sr ratio) and vegetation cover (pollen). We observe that Danish Mesolithic individuals of the Maglemose, Kongemose and Ertebølle cultures form a distinct genetic cluster related to other Western European hunter-gatherers. Despite shifts in material culture they displayed genetic homogeneity from around 10,500 to 5,900 calibrated years before present, when Neolithic farmers with Anatolian-derived ancestry arrived. Although the Neolithic transition was delayed by more than a millennium relative to Central Europe, it was very abrupt and resulted in a population turnover with limited genetic contribution from local hunter-gatherers. The succeeding Neolithic population, associated with the Funnel Beaker culture, persisted for only about 1,000 years before immigrants with eastern Steppe-derived ancestry arrived. This second and equally rapid population replacement gave rise to the Single Grave culture with an ancestry profile more similar to present-day Danes. In our multiproxy dataset, these major demographic events are manifested as parallel shifts in genotype, phenotype, diet and land use.
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| 3. |
- Clayton, Emma L., et al.
(författare)
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Early microgliosis precedes neuronal loss and behavioural impairment in mice with a frontotemporal dementia-causing CHMP2B mutation
- 2017
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Ingår i: Human Molecular Genetics. - : Oxford University Press (OUP). - 0964-6906 .- 1460-2083. ; 26:5, s. 873-887
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Tidskriftsartikel (refereegranskat)abstract
- Frontotemporal dementia (FTD)-causing mutations in the CHMP2B gene lead to the generation of mutant C-terminally truncated CHMP2B. We report that transgenic mice expressing endogenous levels of mutant CHMP2B developed late-onset brain volume loss associated with frank neuronal loss and FTD-like changes in social behaviour. These data are the first to show neurodegeneration in mice expressing mutant CHMP2B and indicate that our mouse model is able to recapitulate neurodegenerative changes observed in FTD. Neuroinflammation has been increasingly implicated in neurodegeneration, including FTD. Therefore, we investigated neuroinflammation in our CHMP2B mutant mice. We observed very early microglial proliferation that develops into a clear pro-inflammatory phenotype at late stages. Importantly, we also observed a similar inflammatory profile in CHMP2B patient frontal cortex. Aberrant microglial function has also been implicated in FTD caused by GRN, MAPT and C9orf72 mutations. The presence of early microglial changes in our CHMP2B mutant mice indicates neuroinflammation may be a contributing factor to the neurodegeneration observed in FTD.
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| 4. |
- Jansen, Willemijn J, et al.
(författare)
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Prevalence Estimates of Amyloid Abnormality Across the Alzheimer Disease Clinical Spectrum.
- 2022
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Ingår i: JAMA neurology. - : American Medical Association (AMA). - 2168-6157 .- 2168-6149. ; 79:3, s. 228-243
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Tidskriftsartikel (refereegranskat)abstract
- One characteristic histopathological event in Alzheimer disease (AD) is cerebral amyloid aggregation, which can be detected by biomarkers in cerebrospinal fluid (CSF) and on positron emission tomography (PET) scans. Prevalence estimates of amyloid pathology are important for health care planning and clinical trial design.To estimate the prevalence of amyloid abnormality in persons with normal cognition, subjective cognitive decline, mild cognitive impairment, or clinical AD dementia and to examine the potential implications of cutoff methods, biomarker modality (CSF or PET), age, sex, APOE genotype, educational level, geographical region, and dementia severity for these estimates.This cross-sectional, individual-participant pooled study included participants from 85 Amyloid Biomarker Study cohorts. Data collection was performed from January 1, 2013, to December 31, 2020. Participants had normal cognition, subjective cognitive decline, mild cognitive impairment, or clinical AD dementia. Normal cognition and subjective cognitive decline were defined by normal scores on cognitive tests, with the presence of cognitive complaints defining subjective cognitive decline. Mild cognitive impairment and clinical AD dementia were diagnosed according to published criteria.Alzheimer disease biomarkers detected on PET or in CSF.Amyloid measurements were dichotomized as normal or abnormal using cohort-provided cutoffs for CSF or PET or by visual reading for PET. Adjusted data-driven cutoffs for abnormal amyloid were calculated using gaussian mixture modeling. Prevalence of amyloid abnormality was estimated according to age, sex, cognitive status, biomarker modality, APOE carrier status, educational level, geographical location, and dementia severity using generalized estimating equations.Among the 19097 participants (mean [SD] age, 69.1 [9.8] years; 10148 women [53.1%]) included, 10139 (53.1%) underwent an amyloid PET scan and 8958 (46.9%) had an amyloid CSF measurement. Using cohort-provided cutoffs, amyloid abnormality prevalences were similar to 2015 estimates for individuals without dementia and were similar across PET- and CSF-based estimates (24%; 95% CI, 21%-28%) in participants with normal cognition, 27% (95% CI, 21%-33%) in participants with subjective cognitive decline, and 51% (95% CI, 46%-56%) in participants with mild cognitive impairment, whereas for clinical AD dementia the estimates were higher for PET than CSF (87% vs 79%; mean difference, 8%; 95% CI, 0%-16%; P=.04). Gaussian mixture modeling-based cutoffs for amyloid measures on PET scans were similar to cohort-provided cutoffs and were not adjusted. Adjusted CSF cutoffs resulted in a 10% higher amyloid abnormality prevalence than PET-based estimates in persons with normal cognition (mean difference, 9%; 95% CI, 3%-15%; P=.004), subjective cognitive decline (9%; 95% CI, 3%-15%; P=.005), and mild cognitive impairment (10%; 95% CI, 3%-17%; P=.004), whereas the estimates were comparable in persons with clinical AD dementia (mean difference, 4%; 95% CI, -2% to 9%; P=.18).This study found that CSF-based estimates using adjusted data-driven cutoffs were up to 10% higher than PET-based estimates in people without dementia, whereas the results were similar among people with dementia. This finding suggests that preclinical and prodromal AD may be more prevalent than previously estimated, which has important implications for clinical trial recruitment strategies and health care planning policies.
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| 5. |
- Johannsen, A., et al.
(författare)
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Effects of stabilized stannous fluoride dentifrice on dental calculus, dental plaque, gingivitis, halitosis and stain: A systematic review
- 2019
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Ingår i: Heliyon. - : Elsevier BV. - 2405-8440. ; 5:12
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Tidskriftsartikel (refereegranskat)abstract
- Objectives: The aim of the present systematic review was to examine the scientific evidence for the efficacy of stabilized stannous fluoride (SnF2) dentifrice in relation to dental calculus, dental plaque, gingivitis, halitosis and staining. Data and sources: Medline OVID, Embase.com, and the Cochrane Library were searched from database inception until June 2017. Six researchers independently selected studies, extracted data, and assessed methodological quality. A meta-analysis of the 6-month gingivitis studies was done. Risk of bias was estimated using a checklist from the Swedish Agency for Health Technology Assessment (SBU, 2018). Study selection: Two studies on dental calculus, 21 on dental plaque and gingivitis, 4 on halitosis, and 5 on stain met the inclusion criteria. Risk of bias was high for the studies on dental calculus, halitosis, and stain, and varied for the dental plaque and gingivitis studies. Significant reductions in dental calculus and in halitosis were reported for the SnF2 dentifrice; no differences in stain reduction were noted. A meta-analysis on gingivitis found better results for the SnF2 dentifrice compared to other dentifrices, though the results of the individual trials in the metaanalysesshowed a substantial heterogeneity. Conclusions: The present review found that stabilized SnF2 toothpaste had a positive effect on the reduction of dental calculus build-up, dental plaque, gingivitis, stain and halitosis. A tendency towards a more pronounced effect than using toothpastes not containing SnF2 was found. However, a new generation of well conducted randomized trials are needed to further support these findings. Clinical relevance: Adding a SnF2 toothpaste to the daily oral care routine is an easy strategy that may have multiple oral health benefits.
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| 6. |
- Konradsson, Katarina, et al.
(författare)
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Stabilized stannous fluoride dentifrice in relation to dental caries, dental erosion and dentin hypersensitivity: A systematic review
- 2020
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Ingår i: American Journal of Dentistry. - : Mosher & Linder. - 0894-8275. ; 33:2, s. 95-105
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Tidskriftsartikel (refereegranskat)abstract
- Purpose: To review the scientific evidence for the efficacy of stabilized stannous fluoride (SnF2) dentifrice in relation to dental caries, dental erosion and dentin hypersensitivity. Methods: Medline OVID, Embase.com, and the Cochrane Library were searched until January 2018. Two researchers independently selected studies according to inclusion and exclusion criteria, data were extracted, the risk of bias in eligible studies was assessed and a meta-analysis was performed wherever feasible. Results: Three studies on dental caries, eight studies on dental erosion and 11 on dentin hypersensitivity were included. Risk of bias was judged as high for most of the caries and erosion studies and low or medium for the hypersensitivity studies. A similar or slightly higher anti-caries activity compared with nonstannous fluoride dentifrices was observed. Stannous fluoride showed a greater anti-erosive potential in seven of the eight studies. A mean difference score in favor of stannous fluoride dentifrices compared with controls was found in a meta-analysis including six 8-week hypersensitivity studies.
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| 7. |
- Küçükali, Fahri, et al.
(författare)
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Whole-exome rare-variant analysis of Alzheimer's disease and related biomarker traits
- 2023
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Ingår i: Alzheimer's & Dementia. - : John Wiley & Sons. - 1552-5260 .- 1552-5279. ; 19:6, s. 2317-2331
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Tidskriftsartikel (refereegranskat)abstract
- INTRODUCTION: Despite increasing evidence of a role of rare genetic variation in the risk of Alzheimer's disease (AD), limited attention has been paid to its contribution to AD-related biomarker traits indicative of AD-relevant pathophysiological processes.METHODS: We performed whole-exome gene-based rare-variant association studies (RVASs) of 17 AD-related traits on whole-exome sequencing (WES) data generated in the European Medical Information Framework for Alzheimer's Disease Multimodal Biomarker Discovery (EMIF-AD MBD) study (n = 450) and whole-genome sequencing (WGS) data from ADNI (n = 808).RESULTS: Mutation screening revealed a novel probably pathogenic mutation (PSEN1 p.Leu232Phe). Gene-based RVAS revealed the exome-wide significant contribution of rare coding variation in RBKS and OR7A10 to cognitive performance and protection against left hippocampal atrophy, respectively.DISCUSSION: The identification of these novel gene-trait associations offers new perspectives into the role of rare coding variation in the distinct pathophysiological processes culminating in AD, which may lead to identification of novel therapeutic and diagnostic targets.
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| 8. |
- Rostgaard, Nina, et al.
(författare)
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TMEM106B and ApoE polymorphisms in CHMP2B-mediated frontotemporal dementia (FTD-3)
- 2017
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Ingår i: Neurobiology of Aging. - : Elsevier BV. - 0197-4580. ; 59, s. 1-221
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Tidskriftsartikel (refereegranskat)abstract
- Single-nucleotide polymorphisms in the TMEM106B gene have been identified as a risk factor in frontotemporal dementia (FTD). The major allele of SNP rs3173615 is a risk factor in sporadic FTD, whereas the minor allele seems protective in GRN- and C9orf72-mediated FTD. The role of apolipoprotein E (ApoE) in FTD is uncertain, though an established risk factor in Alzheimer's disease. In a unique Danish family, inherited FTD is caused by a mutation in the CHMP2B gene located on chromosome 3 (FTD-3). In this family, both risk factors TMEM106B and ApoE were analyzed and correlated to age at onset (AAO) and progression in terms of age at institutionalization (AAI) and age at death (AAD). Although TMEM106B and CHMP2B share cellular function in that both localize to endolysosomes, TMEM106B genotypes appeared to have no influence on the clinical disease course. ApoE ε4 was found to be a protective factor with later AAO and AAI, whereas ε2 seemed to aggravate the disease with earlier AAO and AAD. These results indicate ApoE ε2 as a risk factor in FTD-3 and suggest a protective role of ε4.
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| 9. |
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| 10. |
- Bos, Isabelle, et al.
(författare)
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The frequency and influence of dementia risk factors in prodromal Alzheimer's disease
- 2017
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Ingår i: Neurobiology of Aging. - : Elsevier. - 0197-4580 .- 1558-1497. ; 56, s. 33-40
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Tidskriftsartikel (refereegranskat)abstract
- We investigated whether dementia risk factors were associated with prodromal Alzheimer's disease (AD) according to the International Working Group-2 and National Institute of Aging-Alzheimer's Association criteria, and with cognitive decline. A total of 1394 subjects with mild cognitive impairment from 14 different studies were classified according to these research criteria, based on cognitive performance and biomarkers. We compared the frequency of 10 risk factors between the subgroups, and used Cox-regression to examine the effect of risk factors on cognitive decline. Depression, obesity, and hypercholesterolemia occurred more often in individuals with low-AD-likelihood, compared with those with a high-AD-likelihood. Only alcohol use increased the risk of cognitive decline, regardless of AD pathology. These results suggest that traditional risk factors for AD are not associated with prodromal AD or with progression to dementia, among subjects with mild cognitive impairment. Future studies should validate these findings and determine whether risk factors might be of influence at an earlier stage (i.e., preclinical) of AD.
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| 11. |
- Buerger, Katharina, et al.
(författare)
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Validation of Alzheimer's disease CSF and plasma biological markers: the multicentre reliability study of the pilot European Alzheimer's Disease Neuroimaging Initiative (E-ADNI).
- 2009
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Ingår i: Experimental gerontology. - : Elsevier BV. - 1873-6815 .- 0531-5565. ; 44:9, s. 579-85
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Alzheimer's Disease Neuroimaging Initiatives ("ADNI") aim to validate neuroimaging and biochemical markers of Alzheimer's disease (AD). Data of the pilot European-ADNI (E-ADNI) biological marker programme of cerebrospinal fluid (CSF) and plasma candidate biomarkers are reported. METHODS: Six academic EADC centres recruited 49 subjects (healthy controls, subjects with mild cognitive impairment (MCI) and AD). We measured CSF beta-amyloid 42 (CSF Abeta42), total tau-protein (t-tau), phosphorylated tau-proteins (P-tau181, P-tau231), plasma beta-amyloid 40 and 42 (Abeta40/Abeta42). Immediate fresh shipment was compared to freezing and later shipment on dry ice. RESULTS: CSF T-tau (fresh samples) was increased in AD versus controls (p=0.049), CSF Abeta42 (frozen samples) was decreased in MCI and AD (p=0.02), as well as plasma Abeta40 (fresh and frozen samples) in AD (p=0.049 and p=0.016). Pooled values of neurochemical parameters and ratios thereof were different between centres (p<0.005). Analysis of frozen samples yielded higher diagnostic accuracy than immediate fresh shipment with 100% (fresh: 100%) correctly classified in control subjects, 100% (78%) in MCI, 91% (91%) in AD. CONCLUSION: The use of frozen rather than fresh samples renders higher diagnostic accuracy within a multicentre context. We confirmed the feasibility of a multicentre AD biomarker programme for future clinical trials.
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| 12. |
- Frisoni, Giovanni B, et al.
(författare)
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The pilot European Alzheimer's Disease Neuroimaging Initiative of the European Alzheimer's Disease Consortium.
- 2008
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Ingår i: Alzheimer's & dementia : the journal of the Alzheimer's Association. - : Wiley. - 1552-5279. ; 4:4, s. 255-64
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: In North America, the Alzheimer's Disease Neuroimaging Initiative (ADNI) has established a platform to track the brain changes of Alzheimer's disease. A pilot study has been carried out in Europe to test the feasibility of the adoption of the ADNI platform (pilot E-ADNI). METHODS: Seven academic sites of the European Alzheimer's Disease Consortium (EADC) enrolled 19 patients with mild cognitive impairment (MCI), 22 with AD, and 18 older healthy persons by using the ADNI clinical and neuropsychological battery. ADNI compliant magnetic resonance imaging (MRI) scans, cerebrospinal fluid, and blood samples were shipped to central repositories. Medial temporal atrophy (MTA) and white matter hyperintensities (WMH) were assessed by a single rater by using visual rating scales. RESULTS: Recruitment rate was 3.5 subjects per month per site. The cognitive, behavioral, and neuropsychological features of the European subjects were very similar to their U.S. counterparts. Three-dimensional T1-weighted MRI sequences were successfully performed on all subjects, and cerebrospinal fluid samples were obtained from 77%, 68%, and 83% of AD patients, MCI patients, and controls, respectively. Mean MTA score showed a significant increase from controls (left, right: 0.4, 0.3) to MCI patients (0.9, 0.8) to AD patients (2.3, 2.0), whereas mean WMH score did not differ among the three diagnostic groups (between 0.7 and 0.9). The distribution of both MRI markers was comparable to matched US-ADNI subjects. CONCLUSIONS: Academic EADC centers can adopt the ADNI platform to enroll MCI and AD patients and older controls with global cognitive and structural imaging features remarkably similar to those of the US-ADNI.
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| 13. |
- Holm, Ida Elisabeth, et al.
(författare)
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A reassessment of the neuropathology of frontotemporal dementia linked to chromosome 3
- 2007
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Ingår i: Journal of Neuropathology and Experimental Neurology. - 1554-6578. ; 66:10, s. 884-891
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Tidskriftsartikel (refereegranskat)abstract
- A large Danish family has previously been reported in which autosomal dominant frontotemporal dementia (FTD) is genetically linked to chromosome 3 (FTD-3). A mutation was recently identified in the CHMP2B gene that is probably responsible for causing disease in this family. Because of its neuropathologic findings, FTD-3 was originally categorized as a subtype of frontotemporal lobar degeneration, termed "dementia lacking distinctive histopathology." We now report a reevaluation of the neuropathologic changes in this family. Postmortem material from 4 affected family members was available for examination. Gross examination revealed generalized cortical atrophy that was most severe in frontal and temporal cortices. Microscopy showed loss of cortical neurons. microvacuolation of layer 11, mild gliosis, and demyelination of the deep white matter. Results of immunohistochemical staining for alpha-synuclein, prion protein, neurofilament, and tau protein were unremarkable. Variable numbers of small, round, ubiquitin-positive cytoplasmic inclusions were present in the dentate granule layer of the hippocampus in all 4 cases. Rare ubiquitin-positive inclusions were also found in frontal and temporal cortical neurons. These inclusions were also positive for p62 but not for TDP-43. The finding of ubiquitin- and p62-positive, TDP-43-neaative cytoplasmic inclusions in the hippocampus and neocortex suggests reclassification of the neuropathology of FTD-3 as a unique subtype of frontotemporal lobar degeneration with ubiquitin-positive inclusions that are TDP-43 -negative.
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| 14. |
- Jansen, Willemijn J, et al.
(författare)
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Association of Cerebral Amyloid-β Aggregation With Cognitive Functioning in Persons Without Dementia.
- 2018
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Ingår i: JAMA psychiatry. - : American Medical Association (AMA). - 2168-6238 .- 2168-622X. ; 75:1, s. 84-95
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Tidskriftsartikel (refereegranskat)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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| 15. |
- Jansen, Willemijn J, et al.
(författare)
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Prevalence of cerebral amyloid pathology in persons without dementia: a meta-analysis.
- 2015
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Ingår i: JAMA. - : American Medical Association (AMA). - 1538-3598 .- 0098-7484. ; 313:19, s. 1924-38
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Tidskriftsartikel (refereegranskat)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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| 16. |
- Kim, Min, et al.
(författare)
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Primary fatty amides in plasma associated with brain amyloid burden, hippocampal volume, and memory in the European Medical Information Framework for Alzheimer's Disease biomarker discovery cohort
- 2019
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Ingår i: Alzheimer's & Dementia. - : Elsevier. - 1552-5260 .- 1552-5279. ; 15:6, s. 817-827
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Tidskriftsartikel (refereegranskat)abstract
- INTRODUCTION: A critical and as-yet unmet need in Alzheimer's disease (AD) is the discovery of peripheral small molecule biomarkers. Given that brain pathology precedes clinical symptom onset, we set out to test whether metabolites in blood associated with pathology as indexed by cerebrospinal fluid (CSF) AD biomarkers.METHODS: This study analyzed 593 plasma samples selected from the European Medical Information Framework for Alzheimer's Disease Multimodal Biomarker Discovery study, of individuals who were cognitively healthy (n = 242), had mild cognitive impairment (n = 236), or had AD-type dementia (n = 115). Logistic regressions were carried out between plasma metabolites (n = 883) and CSF markers, magnetic resonance imaging, cognition, and clinical diagnosis.RESULTS: Eight metabolites were associated with amyloid β and one with t-tau in CSF, these were primary fatty acid amides (PFAMs), lipokines, and amino acids. From these, PFAMs, glutamate, and aspartate also associated with hippocampal volume and memory.DISCUSSION: PFAMs have been found increased and associated with amyloid β burden in CSF and clinical measures.
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| 17. |
- Mattsson, Niklas, et al.
(författare)
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Prevalence of the apolipoprotein E epsilon 4 allele in amyloid beta positive subjects across the spectrum of Alzheimers disease
- 2018
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Ingår i: Alzheimer's & Dementia. - : ELSEVIER SCIENCE INC. - 1552-5260 .- 1552-5279. ; 14:7, s. 913-924
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Tidskriftsartikel (refereegranskat)abstract
- Introduction: Apolipoprotein E (APOE) epsilon 4 is the major genetic risk factor for Alzheimers disease (AD), but its prevalence is unclear because earlier studies did not require biomarker evidence of amyloid beta(A beta) pathology. Methods: We included 3451 A beta+ subjects (853 AD-type dementia, 1810 mild cognitive impairment, and 788 cognitively normal). Generalized estimating equation models were used to assess APOE epsilon 4 prevalence in relation to age, sex, education, and geographical location. Results: The APOE epsilon 4 prevalence was 66% in AD-type dementia, 64% in mild cognitive impairment, and 51% in cognitively normal, and it decreased with advancing age in A beta+ cognitively normal and A beta+ mild cognitive impairment (P amp;lt;.05) but not in A beta+ AD dementia (P =.66). The prevalence was highest in Northern Europe but did not vary by sex or education. Discussion: The APOE E4 prevalence in AD was higher than that in previous studies, which did not require presence of A beta pathology. Furthermore, our results highlight disease heterogeneity related to age and geographical location. (C) 2018 the Alzheimers Association. Published by Elsevier Inc. All rights reserved.
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| 18. |
- Mattsson, Niklas, et al.
(författare)
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Prevalence of the apolipoprotein E ε4 allele in amyloid β positive subjects across the spectrum of Alzheimer's disease
- 2018
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Ingår i: Alzheimer's and Dementia. - : Wiley. - 1552-5260 .- 1552-5279. ; 14:7, s. 913-924
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Tidskriftsartikel (refereegranskat)abstract
- Introduction: Apolipoprotein E (APOE) ε4 is the major genetic risk factor for Alzheimer's disease (AD), but its prevalence is unclear because earlier studies did not require biomarker evidence of amyloid β (Aβ) pathology. Methods: We included 3451 Aβ+ subjects (853 AD-type dementia, 1810 mild cognitive impairment, and 788 cognitively normal). Generalized estimating equation models were used to assess APOE ε4 prevalence in relation to age, sex, education, and geographical location. Results: The APOE ε4 prevalence was 66% in AD-type dementia, 64% in mild cognitive impairment, and 51% in cognitively normal, and it decreased with advancing age in Aβ+ cognitively normal and Aβ+ mild cognitive impairment (P <.05) but not in Aβ+ AD dementia (P =.66). The prevalence was highest in Northern Europe but did not vary by sex or education. Discussion: The APOE ε4 prevalence in AD was higher than that in previous studies, which did not require presence of Aβ pathology. Furthermore, our results highlight disease heterogeneity related to age and geographical location.
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| 19. |
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| 20. |
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| 21. |
- Shi, Liu, et al.
(författare)
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Dickkopf-1 Overexpression in vitro Nominates Candidate Blood Biomarkers Relating to Alzheimer's Disease Pathology.
- 2020
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Ingår i: Journal of Alzheimer's disease : JAD. - : IOS Press. - 1875-8908 .- 1387-2877. ; 77:3, s. 1353-1368
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Tidskriftsartikel (refereegranskat)abstract
- Previous studies suggest that Dickkopf-1 (DKK1), an inhibitor of Wnt signaling, plays a role in amyloid-induced toxicity and hence Alzheimer's disease (AD). However, the effect of DKK1 expression on protein expression, and whether such proteins are altered in disease, is unknown.We aim to test whether DKK1 induced protein signature obtained in vitro were associated with markers of AD pathology as used in the amyloid/tau/neurodegeneration (ATN) framework as well as with clinical outcomes.We first overexpressed DKK1 in HEK293A cells and quantified 1,128 proteins in cell lysates using aptamer capture arrays (SomaScan) to obtain a protein signature induced by DKK1. We then used the same assay to measure the DKK1-signature proteins in human plasma in two large cohorts, EMIF (n = 785) and ANM (n = 677).We identified a 100-protein signature induced by DKK1 in vitro. Subsets of proteins, along with age and apolipoprotein E ɛ4 genotype distinguished amyloid pathology (A + T-N-, A+T+N-, A+T-N+, and A+T+N+) from no AD pathology (A-T-N-) with an area under the curve of 0.72, 0.81, 0.88, and 0.85, respectively. Furthermore, we found that some signature proteins (e.g., Complement C3 and albumin) were associated with cognitive score and AD diagnosis in both cohorts.Our results add further evidence for a role of DKK regulation of Wnt signaling in AD and suggest that DKK1 induced signature proteins obtained in vitro could reflect theATNframework as well as predict disease severity and progression in vivo.
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| 22. |
- Shi, Liu, et al.
(författare)
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Discovery and validation of plasma proteomic biomarkers relating to brain amyloid burden by SOMAscan assay.
- 2019
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Ingår i: Alzheimer's & dementia : the journal of the Alzheimer's Association. - : Wiley. - 1552-5279 .- 1552-5260. ; 15:11, s. 1478-1488
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Tidskriftsartikel (refereegranskat)abstract
- Plasma proteins have been widely studied as candidate biomarkers to predict brain amyloid deposition to increase recruitment efficiency in secondary prevention clinical trials for Alzheimer's disease. Most such biomarker studies are targeted to specific proteins or are biased toward high abundant proteins.4001 plasma proteins were measured in two groups of participants (discovery group=516, replication group=365) selected from the European Medical Information Framework for Alzheimer's disease Multimodal Biomarker Discovery study, all of whom had measures of amyloid.A panel of proteins (n=44), along with age and apolipoprotein E (APOE) ε4, predicted brain amyloid deposition with good performance in both the discovery group (area under the curve=0.78) and the replication group (area under the curve=0.68). Furthermore, a causal relationship between amyloid and tau was confirmed by Mendelian randomization.The results suggest that high-dimensional plasma protein testing could be a useful and reproducible approach for measuring brain amyloid deposition.
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| 23. |
- Shi, Liu, et al.
(författare)
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Replication study of plasma proteins relating to Alzheimer's pathology.
- 2021
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Ingår i: Alzheimer's & dementia : the journal of the Alzheimer's Association. - : Wiley. - 1552-5279 .- 1552-5260. ; 17:9, s. 1452-1464
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Tidskriftsartikel (refereegranskat)abstract
- This study sought to discover and replicate plasma proteomic biomarkers relating to Alzheimer's disease (AD) including both the "ATN" (amyloid/tau/neurodegeneration) diagnostic framework and clinical diagnosis.Plasma proteins from 972 subjects (372 controls, 409 mild cognitive impairment [MCI], and 191 AD) were measured using both SOMAscan and targeted assays, including 4001 and 25 proteins, respectively.Protein co-expression network analysis of SOMAscan data revealed the relation between proteins and "N" varied across different neurodegeneration markers, indicating that the ATN variants are not interchangeable. Using hub proteins, age, and apolipoprotein E ε4 genotype discriminated AD from controls with an area under the curve (AUC) of 0.81 and MCI convertors from non-convertors with an AUC of 0.74. Targeted assays replicated the relation of four proteins with the ATN framework and clinical diagnosis.Our study suggests that blood proteins can predict the presence of AD pathology as measured in the ATN framework as well as clinical diagnosis.
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| 24. |
- Stamate, Daniel, et al.
(författare)
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A metabolite-based machine learning approach to diagnose Alzheimer-type dementia in blood : Results from the European Medical Information Framework for Alzheimer disease biomarker discovery cohort
- 2019
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Ingår i: Alzheimer’s & Dementia. - : John Wiley & Sons. - 2352-8737. ; 5:C, s. 933-938
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Tidskriftsartikel (refereegranskat)abstract
- IntroductionMachine learning (ML) may harbor the potential to capture the metabolic complexity in Alzheimer Disease (AD). Here we set out to test the performance of metabolites in blood to categorize AD when compared to CSF biomarkers.MethodsThis study analyzed samples from 242 cognitively normal (CN) people and 115 with AD‐type dementia utilizing plasma metabolites (n = 883). Deep Learning (DL), Extreme Gradient Boosting (XGBoost) and Random Forest (RF) were used to differentiate AD from CN. These models were internally validated using Nested Cross Validation (NCV).ResultsOn the test data, DL produced the AUC of 0.85 (0.80–0.89), XGBoost produced 0.88 (0.86–0.89) and RF produced 0.85 (0.83–0.87). By comparison, CSF measures of amyloid, p‐tau and t‐tau (together with age and gender) produced with XGBoost the AUC values of 0.78, 0.83 and 0.87, respectively.DiscussionThis study showed that plasma metabolites have the potential to match the AUC of well‐established AD CSF biomarkers in a relatively small cohort. Further studies in independent cohorts are needed to validate whether this specific panel of blood metabolites can separate AD from controls, and how specific it is for AD as compared with other neurodegenerative disorders.
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| 25. |
- Wallgren, Jakob, 1987-
(författare)
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An insight into the metabolism of New Psychoactive Substances : Structural elucidation of urinary metabolites of synthetic cannabinoids and fentanyl analogues using synthesized reference standards
- 2020
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- New Psychoactive Substances (NPS) is an umbrella term covering hundreds of substances across different drug groups. Many of these substances were originally developed for therapeutic use but have later appeared on the recreational drug market. The use of NPS has been associated with many outbreaks leading to hospitalizations and has been implicated in numerous fatalities worldwide. To be able to analytically detect drugs in a forensic setting is vital in the fight against the abuse of NPS. One of the most notable challenges in detection of NPS is the identification of major urinary metabolites for use as biomarkers. Furthermore, given the lack of reference standards in most metabolism studies, the major urinary metabolites can often only be tentatively determined.This thesis describes the synthesis and analysis of potential metabolites used to identify the exact structures of major metabolites of the synthetic cannabinoid AKB-48, fentanyl and five fentanyl analogues in authentic human urine samples and/or hepatocyte incubations. Synthetic targets were chosen based on previous metabolism studies by our research group. Subsequently, synthetic routes were developed to produce numerous potential metabolites across the studied NPS. The synthesized reference standards were analyzed by LC-QTOF-MS alongside hepatocyte drug incubations and authentic human urine samples. Comparison of the resulting analytical data was used to determine the exact structures of many metabolites. This includes urinary metabolites of AKB-48 with a single hydroxyl group situated on a secondary carbon of the adamantane moiety, or position 3 or 5 of the pentyl side chain. For the studied fentanyls, the β-OH and the 4’-OH metabolites were abundant metabolites identified in hepatocyte incubations while the 4’-OH, 4’-OH-3’-OMe and 3’,4’-diOH were the favored metabolic motifs among the metabolites identified in urine.Additionally, a concise synthetic route to produce synthetic cannabinoid metabolites with the 4-OH-5F pentyl side chain motif was developed and demonstrated for four synthetic cannabinoids. These findings and the developed synthetic routes can be used to provide forensic toxicology laboratories with urinary biomarkers for drug detection. Moreover, the synthesized reference standards of major metabolites can be studied to better understand the toxicity of their parent drugs.
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| 26. |
- Westwood, Sarah, et al.
(författare)
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Validation of Plasma Proteomic Biomarkers Relating to Brain Amyloid Burden in the EMIF-Alzheimer's Disease Multimodal Biomarker Discovery Cohort
- 2020
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Ingår i: Journal of Alzheimer's Disease. - : IOS Press. - 1387-2877 .- 1875-8908. ; 74:1, s. 213-225
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Tidskriftsartikel (refereegranskat)abstract
- We have previously investigated, discovered, and replicated plasma protein biomarkers for use to triage potential trials participants for PET or cerebrospinal fluid measures of Alzheimer's disease (AD) pathology. This study sought to undertake validation of these candidate plasma biomarkers in a large, multi-center sample collection. Targeted plasma analyses of 34 proteins with prior evidence for prediction of in vivo pathology were conducted in up to 1,000 samples from cognitively healthy elderly individuals, people with mild cognitive impairment, and in patients with AD-type dementia, selected from the EMIF-AD catalogue. Proteins were measured using Luminex xMAP, ELISA, and Meso Scale Discovery assays. Seven proteins replicated in their ability to predict in vivo amyloid pathology. These proteins form a biomarker panel that, along with age, could significantly discriminate between individuals with high and low amyloid pathology with an area under the curve of 0.74. The performance of this biomarker panel remained consistent when tested in apolipoprotein E ɛ4 non-carrier individuals only. This blood-based panel is biologically relevant, measurable using practical immunocapture arrays, and could significantly reduce the cost incurred to clinical trials through screen failure.
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| 27. |
- Xu, Jin, et al.
(författare)
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Sex-Specific Metabolic Pathways Were Associated with Alzheimer's Disease (AD) Endophenotypes in the European Medical Information Framework for AD Multimodal Biomarker Discovery Cohort
- 2021
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Ingår i: Biomedicines. - : MDPI. - 2227-9059. ; 9:11
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: physiological differences between males and females could contribute to the development of Alzheimer's Disease (AD). Here, we examined metabolic pathways that may lead to precision medicine initiatives.METHODS: We explored whether sex modifies the association of 540 plasma metabolites with AD endophenotypes including diagnosis, cerebrospinal fluid (CSF) biomarkers, brain imaging, and cognition using regression analyses for 695 participants (377 females), followed by sex-specific pathway overrepresentation analyses, APOE ε4 stratification and assessment of metabolites' discriminatory performance in AD.RESULTS: In females with AD, vanillylmandelate (tyrosine pathway) was increased and tryptophan betaine (tryptophan pathway) was decreased. The inclusion of these two metabolites (area under curve (AUC) = 0.83, standard error (SE) = 0.029) to a baseline model (covariates + CSF biomarkers, AUC = 0.92, SE = 0.019) resulted in a significantly higher AUC of 0.96 (SE = 0.012). Kynurenate was decreased in males with AD (AUC = 0.679, SE = 0.046).CONCLUSIONS: metabolic sex-specific differences were reported, covering neurotransmission and inflammation pathways with AD endophenotypes. Two metabolites, in pathways related to dopamine and serotonin, were associated to females, paving the way to personalised treatment.
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