| 1. |
- George, Sonia, et al.
(författare)
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Lesion of the subiculum reduces the spread of amyloid beta pathology to interconnected brain regions in a mouse model of Alzheimer's disease.
- 2014
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Ingår i: Acta Neuropathologica Communications. - : Springer Science and Business Media LLC. - 2051-5960. ; 2:1
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Tidskriftsartikel (refereegranskat)abstract
- The progressive development of Alzheimer's disease (AD) pathology follows a spatiotemporal pattern in the human brain. In a transgenic (Tg) mouse model of AD expressing amyloid precursor protein (APP) with the arctic (E693G) mutation, pathology spreads along anatomically connected structures. Amyloid-β (Aβ) pathology first appears in the subiculum and is later detected in interconnected brain regions, including the retrosplenial cortex. We investigated whether the spatiotemporal pattern of Aβ pathology in the Tg APP arctic mice to interconnected brain structures can be interrupted by destroying neurons using a neurotoxin and thereby disconnecting the neural circuitry.
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| 2. |
- Nielsen, Henrietta, et al.
(författare)
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NG2 cells, a new trail for Alzheimer's disease mechanisms?
- 2013
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Ingår i: Acta Neuropathologica Communications. - : Springer Science and Business Media LLC. - 2051-5960. ; 1:1
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Tidskriftsartikel (refereegranskat)abstract
- Neuron Glial 2 (NG2) cells are glial cells known to serve as oligodendrocyte progenitors as well as modulators of the neuronal network. Altered NG2 cell morphology and up-regulation as well as increased shedding of the proteoglycan NG2 expressed on the cell surface have been described in rodent models of brain injury. Here we describe alterations in the human NG2 cell population in response to pathological changes characteristic of Alzheimer's disease (AD).
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| 3. |
- Antonios, Gregory, et al.
(författare)
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N-truncated Abeta starting with position four : early intraneuronal accumulation and rescue of toxicity using NT4X-167, a novel monoclonal antibody
- 2013
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Ingår i: Acta neuropathologica communications. - : Springer Science and Business Media LLC. - 2051-5960. ; 1:1, s. 56-
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: The amyloid hypothesis in Alzheimer disease (AD) considers amyloid β peptide (Aβ) deposition causative in triggering down-stream events like neurofibrillary tangles, cell loss, vascular damage and memory decline. In the past years N-truncated Aβ peptides especially N-truncated pyroglutamate AβpE3-42 have been extensively studied. Together with full-length Aβ1-42 and Aβ1-40, N-truncated AβpE3-42 and Aβ4-42 are major variants in AD brain. Although Aβ4-42 has been known for a much longer time, there is a lack of studies addressing the question whether AβpE3-42 or Aβ4-42 may precede the other in Alzheimer's disease pathology.RESULTS: Using different Aβ antibodies specific for the different N-termini of N-truncated Aβ, we discovered that Aβ4-x preceded AβpE3-x intraneuronal accumulation in a transgenic mouse model for AD prior to plaque formation. The novel Aβ4-x immunoreactive antibody NT4X-167 detected high molecular weight aggregates derived from N-truncated Aβ species. While NT4X-167 significantly rescued Aβ4-42 toxicity in vitro no beneficial effect was observed against Aβ1-42 or AβpE3-42 toxicity. Phenylalanine at position four of Aβ was imperative for antibody binding, because its replacement with alanine or proline completely prevented binding. Although amyloid plaques were observed using NT4X-167 in 5XFAD transgenic mice, it barely reacted with plaques in the brain of sporadic AD patients and familial cases with the Arctic, Swedish and the presenilin-1 PS1Δ9 mutation. A consistent staining was observed in blood vessels in all AD cases with cerebral amyloid angiopathy. There was no cross-reactivity with other aggregates typical for other common neurodegenerative diseases showing that NT4X-167 staining is specific for AD.CONCLUSIONS: Aβ4-x precedes AβpE3-x in the well accepted 5XFAD AD mouse model underlining the significance of N-truncated species in AD pathology. NT4X-167 therefore is the first antibody reacting with Aβ4-x and represents a novel tool in Alzheimer research.
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| 4. |
- García-Ayllón, María-Salud, et al.
(författare)
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CSF Presenilin-1 complexes are increased in Alzheimer's disease.
- 2013
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Ingår i: Acta neuropathologica communications. - : Springer Science and Business Media LLC. - 2051-5960. ; 1:1
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Tidskriftsartikel (refereegranskat)abstract
- Presenilin-1 (PS1) is the active component of the amyloid precursor protein cleaving γ-secretase complex. PS1 protein is a transmembrane protein containing multiple hydrophobic regions which presence in cerebrospinal fluid (CSF) has not been measured to date. This study assesses whether PS1 and other components of the γ-secretase complex are present in CSF.
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| 5. |
- Kalimo, Hannu, et al.
(författare)
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The Arctic AβPP mutation leads to Alzheimer's disease pathology with highly variable topographic deposition of differentially truncated Aβ
- 2013
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Ingår i: Acta neuropathologica communications. - : Springer Science and Business Media LLC. - 2051-5960. ; 1:1, s. 60-
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: The Arctic mutation (p.E693G/p.E22G)fs within the β-amyloid (Aβ) region of the β-amyloid precursor protein gene causes an autosomal dominant disease with clinical picture of typical Alzheimer's disease. Here we report the special character of Arctic AD neuropathology in four deceased patients.RESULTS: Aβ deposition in the brains was wide-spread (Thal phase 5) and profuse. Virtually all parenchymal deposits were composed of non-fibrillar, Congo red negative Aβ aggregates. Congo red only stained angiopathic vessels. Mass spectrometric analyses showed that Aβ deposits contained variably truncated and modified wild type and mutated Aβ species. In three of four Arctic AD brains, most cerebral cortical plaques appeared targetoid with centres containing C-terminally (beyond aa 40) and variably N-terminally truncated Aβ surrounded by coronas immunopositive for Aβx-42. In the fourth patient plaque centres contained almost no Aβ making the plaques ring-shaped. The architectural pattern of plaques also varied between different anatomic regions. Tau pathology corresponded to Braak stage VI, and appeared mainly as delicate neuropil threads (NT) enriched within Aβ plaques. Dystrophic neurites were scarce, while neurofibrillary tangles were relatively common. Neuronal perikarya within the Aβ plaques appeared relatively intact.CONCLUSIONS: In Arctic AD brain differentially truncated abundant Aβ is deposited in plaques of variable numbers and shapes in different regions of the brain (including exceptional targetoid plaques in neocortex). The extracellular non-fibrillar Aβ does not seem to cause overt damage to adjacent neurons or to induce formation of neurofibrillary tangles, supporting the view that intracellular Aβ oligomers are more neurotoxic than extracellular Aβ deposits. However, the enrichment of NTs within plaques suggests some degree of intra-plaque axonal damage including accumulation of hp-tau, which may impair axoplasmic transport, and thereby contribute to synaptic loss. Finally, similarly as the cotton wool plaques in AD resulting from exon 9 deletion in the presenilin-1 gene, the Arctic plaques induced only modest glial and inflammatory tissue reaction.
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| 6. |
- Leinonen, Ville, et al.
(författare)
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Diagnostic effectiveness of quantitative [¹⁸F]flutemetamol PET imaging for detection of fibrillar amyloid β using cortical biopsy histopathology as the standard of truth in subjects with idiopathic normal pressure hydrocephalus.
- 2014
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Ingår i: Acta neuropathologica communications. - : Springer Science and Business Media LLC. - 2051-5960. ; 2, s. 46-
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Tidskriftsartikel (refereegranskat)abstract
- INTRODUCTION: PET imaging of amyloid-β (Aβ) in vivo holds promise for aiding in earlier diagnosis and intervention in Alzheimer's disease (AD) and mild cognitive impairment. AD-like Aβ pathology is a common comorbidity in patients with idiopathic normal pressure hydrocephalus (iNPH). Fifty patients with iNPH needing ventriculo-peritoneal shunting or intracranial pressure monitoring underwent [18F]flutemetamol PET before (N = 28) or after (N = 22) surgery. Cortical uptake of [18F]flutemetamol was assessed visually by blinded reviewers, and also quantitatively via standard uptake value ratio (SUVR) in specific neocortical regions in relation to either cerebellum or pons reference region: the cerebral cortex of (prospective studies) or surrounding (retrospective studies) the biopsy site, the contralateral homolog, and a calculated composite brain measure. Aβ pathology in the biopsy specimen (standard of truth [SoT]) was measured using Bielschowsky silver and thioflavin S plaque scores, percentage area of grey matter positive for monoclonal antibody to Aβ (4G8), and overall pathology impression. We set out to find (1) which pair(s) of PET SUVR and pathology SoT endpoints matched best, (2) whether quantitative measures of [18F]flutemetamol PET were better for predicting the pathology outcome than blinded image examination (BIE), and (3) whether there was a better match between PET image findings in retrospective vs. prospective studies.RESULTS: Of the 24 possible endpoint/SoT combinations, the one with composite-cerebellum SUVR and SoT based on overall pathology had the highest Youden index (1.000), receiver operating characteristic area under the curve (1.000), sensitivity (1.000), specificity (1.000), and sum of sensitivity and specificity for the pooled data as well as for the retrospective and prospective studies separately (2.00, for all 3). The BIE sum of sensitivity and specificity, comparable to that for quantitation, was highest using Bielschowsky silver as SoT for all SUVRs (ipsilateral, contralateral, and composite, for both reference regions). The composite SUVR had a 100% positive predictive value (both reference regions) for the overall pathology diagnosis. All SUVRs had a 100% negative predictive value for the Bielschowsky silver result.CONCLUSION: Bielschowsky silver stain and overall pathology judgment showed the strongest associations with imaging results.
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| 7. |
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| 8. |
- Abdellah, Tebani, et al.
(författare)
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Annotation of pituitary neuroendocrine tumors with genome-wide expression analysis
- 2021
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Ingår i: Acta neuropathologica communications. - : BioMed Central (BMC). - 2051-5960. ; 9:1
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Tidskriftsartikel (refereegranskat)abstract
- Pituitary neuroendocrine tumors (PitNETs) are common, generally benign tumors with complex clinical characteristics related to hormone hypersecretion and/or growing sellar tumor mass. PitNETs can be classified based on the expression pattern of anterior pituitary hormones and three main transcriptions factors (TF), SF1, PIT1 and TPIT that regulate differentiation of adenohypophysial cells. Here, we have extended this classification based on the global transcriptomics landscape using tumor tissue from a well-defined cohort comprising 51 PitNETs of different clinical and histological types. The molecular profiles were compared with current classification schemes based on immunohistochemistry. Our results identified three main clusters of PitNETs that were aligned with the main pituitary TFs expression patterns. Our analyses enabled further identification of specific genes and expression patterns, including both known and unknown genes, that could distinguish the three different classes of PitNETs. We conclude that the current classification of PitNETs based on the expression of SF1, PIT1 and TPIT reflects three distinct subtypes of PitNETs with different underlying biology and partly independent from the expression of corresponding hormones. The transcriptomic analysis reveals several potentially targetable tumor-driving genes with previously unknown role in pituitary tumorigenesis.
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| 9. |
- Ashton, Nicholas J., et al.
(författare)
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Increased plasma neurofilament light chain concentration correlates with severity of post-mortem neurofibrillary tangle pathology and neurodegeneration
- 2019
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Ingår i: Acta Neuropathologica Communications. - : Springer Science and Business Media LLC. - 2051-5960. ; 7:1
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Tidskriftsartikel (refereegranskat)abstract
- Alzheimer's disease (AD) is pathologically characterized by the accumulation of amyloid-β (Aβ) plaques, neurofibrillary tangles and widespread neuronal loss in the brain. In recent years, blood biomarkers have emerged as a realistic prospect to highlight accumulating pathology for secondary prevention trials. Neurofilament light chain (NfL), a marker of axonal degeneration, is robustly elevated in the blood of many neurological and neurodegenerative conditions, including AD. A strong relationship with cerebrospinal fluid (CSF) NfL suggests that these biomarker modalities reflect the same pathological process. Yet, the connection between blood NfL and brain tissue pathology has not been directly compared. In this study, longitudinal plasma NfL from cognitively healthy controls (n = 12) and AD participants (n = 57) were quantified by the Simoa platform. On reaching post-mortem, neuropathological assessment was performed on all participants, with additional frozen and paraffin-embedded tissue acquired from 26 participants for further biochemical (Aβ1-42, Aβ1-40, tau) and histological (NfL) evaluation. Plasma NfL concentrations were significantly increased in AD and correlated with cognitive decline, independent of age. Retrospective stratification based on Braak staging revealed that baseline plasma NfL concentrations were associated with higher neurofibrillary tangle pathology at post-mortem. Longitudinal increases in plasma NfL were observed in all Braak groupings; a significant negative association, however, was found between plasma NfL at time point 1 and both its rate of change and annual percentage increase. Immunohistochemical evaluation of NfL in the medial temporal gyrus (MTG) demonstrated an inverse relationship between Braak stages and NfL staining. Importantly, a significant negative correlation was found between the plasma NfL measurement closest to death and the level of NfL staining in the MTG at post-mortem. For the first time, we demonstrate that plasma NfL associates with the severity of neurofibrillary tangle pathology and neurodegeneration in the post-mortem brain.
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| 10. |
- Bady, Pierre, et al.
(författare)
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DNA methylation-based age acceleration observed in IDH wild-type glioblastoma is associated with better outcome - including in elderly patients
- 2022
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Ingår i: Acta neuropathologica communications. - : BMC. - 2051-5960. ; 10:1
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Tidskriftsartikel (refereegranskat)abstract
- Elderly patients represent a growing proportion of individuals with glioblastoma, who however, are often excluded from clinical trials owing to poor expected prognosis. We aimed at identifying age-related molecular differences that would justify and guide distinct treatment decisions in elderly glioblastoma patients. The combined DNA methylome (450 k) of four IDH wild-type glioblastoma datasets, comprising two clinical trial cohorts, was interrogated for differences based on the patients age, DNA methylation (DNAm) age acceleration (DNAm age "Horvath-clock" minus patient age), DNA methylation-based tumor classification (Heidelberg), entropy, and functional methylation of DNA damage response (DDR) genes. Age dependent methylation included 19 CpGs (p-value <= 0.1, Bonferroni corrected), comprising a CpG located in the ELOVL2 gene that is part of a 13-gene forensic age predictor. Most of the age related CpGs (n = 16) were also associated with age acceleration that itself was associated with a large number of CpGs (n = 50,551). Over 70% age acceleration-associated CpGs (n = 36,348) overlapped with those associated with the DNA methylation based tumor classification (n = 170,759). Gene set enrichment analysis identified associated pathways, providing insights into the biology of DNAm age acceleration and respective commonalities with glioblastoma classification. Functional methylation of several DDR genes, defined as correlation of methylation with gene expression (r <= -0.3), was associated with age acceleration (n = 8), tumor classification (n = 12), or both (n = 4), the latter including MGMT. DNAm age acceleration was significantly associated with better outcome in both clinical trial cohorts, whereof one comprised only elderly patients. Multivariate analysis included treatment (RT, RT/TMZ -> TMZ; TMZ, RT), MGMT promoter methylation status, and interaction with treatment. In conclusion, DNA methylation features of age acceleration are an integrative part of the methylation-based tumor classification (RTK I, RTK II, MES), while patient age seems hardly reflected in the glioblastoma DNA methylome. We found no molecular evidence justifying other treatments in elderly patients, not owing to frailty or co-morbidities.
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