| 1. |
- Buerger, Katharina, et al.
(författare)
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CSF phosphorylated tau protein correlates with neocortical neurofibrillary pathology in Alzheimer's disease.
- 2006
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Ingår i: Brain. - : Oxford University Press (OUP). - 0006-8950 .- 1460-2156. ; 129:Pt 11, s. 3035-41
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Tidskriftsartikel (refereegranskat)abstract
- Hyperphosphorylated tau protein (P-tau) in CSF is a core biomarker candidate of Alzheimer's disease. Hyperphosphorylation of tau is thought to lead to neurofibrillary changes, a neuropathological hallmark of this type of dementia. Currently, the question is unresolved whether CSF levels of P-tau reflect neurofibrillary changes within the brain of a patient with the illness. Twenty-six patients were included with intra-vitam CSF as well as post-mortem neuropathological data. In the CSF, P-tau phosphorylated at threonine 231 (P-tau231P) was analysed. Post-mortem, scores of neurofibrillary tangles (NFT) and neuritic plaques (NP) were assessed in frontal, temporal, parietal and hippocampal cortical areas. In the same cortical regions, load of hyperphosphorylated tau protein (HP-tau load) was determined. Concentrations of P-tau231P were measured in frontal cortex homogenates. We found significant correlations between CSF P-tau231P concentrations and scores of NFTs and HP-tau load in all neocortical regions studied. The score of NPs was correlated with CSF P-tau231P only within the frontal cortex. There was a correlation between P-tau231P in CSF and brain homogenates. These findings indicate that CSF P-tau231P may serve as an in vivo surrogate biomarker of neurofibrillary pathology in Alzheimer's disease.
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| 2. |
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| 3. |
- Cervenka, Simon, et al.
(författare)
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Support for dopaminergic hypoactivity in restless legs syndrome : a PET study on D2-receptor binding
- 2006
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Ingår i: Brain. - Karolinska Univ Hosp Solna, Dept Clin Neurosci, Psychol Sect, Karolinska Inst, SE-17176 Stockholm, Sweden. Karolinska Univ Hosp Huddinge, Div Clin Pharmacol, Dept Lab Med, Stockholm, Sweden. Karolinska Univ Hosp Huddinge, Dept Neurol, Stockholm, Sweden. GlaxoSmithKline Inc, Translat Med & Genet, Cambridge, England. Univ Manchester, Wolfson Mol Imaging Ctr, Manchester, Lancs, England. GlaxoSmithKline Inc, Neurol Discovery Med, Harlow, Essex, England. : OXFORD UNIV PRESS. - 0006-8950 .- 1460-2156. ; 129, s. 2017-2028
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Tidskriftsartikel (refereegranskat)abstract
- Clinical observations support a central role of the dopamine system in restless legs syndrome (RLS) but previous imaging studies of striatal dopamine D2-receptors have yielded inconclusive results. Extrastriatal dopaminergic function has hitherto not been investigated. Sixteen RLS patients naive to dopaminergic drugs and sixteen matched control subjects were examined with PET. [C-11]Raclopride and [C-11]FLB 457 were used to estimate D2-receptor availability in striatum and extrastriatal regions, respectively. Examinations were performed both in the morning (starting between 10:00 and 12:00 h) and evening (starting at 18:00 h). Measures were taken to monitor and control for head movement during data acquisition. In the striatum, patients had significantly higher [C-11]raclopride binding potential (BP) values than controls. In extrastriatal regions, [C-11]FLB 457 BP was higher in patients than controls, and in the regional analysis the difference was statistically significant in subregions of thalamus and the anterior cingulate cortex. The diurnal variability in BP with [C-11]FLB 457 and [C-11]raclopride was within the previously reported test-retest reproducibility for both radioligands. The study supports involvement of the dopamine system in both striatal and extrastriatal brain regions in the pathophysiology of RLS. The brain regions where differences in D2-receptor binding were shown are implicated in the regulation of affective and motivational aspects of sensory processing, suggesting a possible pathway for sensory symptoms in RLS. Increased D2-receptor availability in RLS may correspond to higher receptor densities or lower levels of endogenous dopamine. Both interpretations are consistent with the hypothesis of hypoactive dopaminergic neurotransmission in RLS, as increased receptor levels can be owing to receptor upregulation in response to low levels of endogenous dopamine. The results do not support variations in dopamine D2-receptor availability as a correlate to the diurnal rhythm of RLS symptoms.
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| 4. |
- Donadio, Vincenzo, et al.
(författare)
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Phosphorylated α-synuclein in skin Schwann cells : a new biomarker for multiple system atrophy
- 2023
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Ingår i: Brain. - : Oxford University Press. - 0006-8950 .- 1460-2156. ; 146:3, s. 1065-1074
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Tidskriftsartikel (refereegranskat)abstract
- Multiple system atrophy (MSA) is characterized by accumulation of phosphorylated α-synuclein (p-syn) as glial cytoplasmic inclusions in the brain and a specific biomarker for this disorder is urgently needed. We aimed at investigating if p-syn can also be detected in skin Remak non-myelinating Schwann cells (RSCs) as Schwann cell cytoplasmic inclusions (SCCi) and may represent a reliable clinical biomarker for MSA.This cross-sectional diagnostic study evaluated skin p-syn in 96 patients: 46 with probable MSA (29 with parkinsonism type MSA and 17 with cerebellar type MSA), 34 with Parkinson's disease (PD) and 16 with dementia with Lewy bodies (DLB). We also included 50 healthy control subjects. Patients were recruited from five different medical centres. P-syn aggregates in skin sections were stained by immunofluorescence, followed by analyses with confocal microscopy and immuno-electron microscopy. All analyses were performed in a blinded fashion.Overall, p-syn aggregates were found in 78% of MSA patients and 100% of patients with PD/DLB, whereas they could not be detected in controls. As for neuronal aggregates 78% of MSA patients were positive for p-syn in somatic neurons, whereas all PD/DLB patients were positive in autonomic neurons. When analysing the presence of p-syn in RSCs, 74% of MSA patients were positive, whereas no such SCCi could be observed in PD/DLB patients. Analyses by immuno-electron microscopy confirmed that SCCi were only found in cases with MSA and thus absent in those with PD/DLB.In conclusion, our findings demonstrate that (i) fibrillar p-syn in RSCs is a pathological hallmark of MSA and may be used as a specific and sensitive disease biomarker; (ii) in Lewy body synucleinopathies (PD/DLB) only neurons contain p-syn deposits; and (iii) the cell-specific deposition of p-syn in the skin thus mirrors that of the brain in many aspects and suggests that non-myelinated glial cells are also involved in the MSA pathogenesis.
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| 5. |
- Ebrahimi-Fakhari, Darius, et al.
(författare)
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Defining the clinical, molecular and imaging spectrum of adaptor protein complex 4-associated hereditary spastic paraplegia
- 2020
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Ingår i: Brain. - OXFORD ENGLAND : Oxford University Press (OUP). - 0006-8950 .- 1460-2156. ; 143:10, s. 2929-2944
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Tidskriftsartikel (refereegranskat)abstract
- Bi-allelic loss-of-function variants in genes that encode subunits of the adaptor protein complex 4 (AP-4) lead to prototypical yet poorly understood forms of childhood-onset and complex hereditary spastic paraplegia: SPG47 (AP4B1), SPG50 (AP4M1), SPG51 (AP4E1) and SPG52 (AP4S1). Here, we report a detailed cross-sectional analysis of clinical, imaging and molecular data of 156 patients from 101 families. Enrolled patients were of diverse ethnic backgrounds and covered a wide age range (1.0-49.3 years). While the mean age at symptom onset was 0.8 +/- 0.6 years [standard deviation (SD), range 0.2-5.0], the mean age at diagnosis was 10.2 +/- 8.5 years (SD, range 0.1-46.3). We define a set of core features: early-onset developmental delay with delayed motor milestones and significant speech delay (50% non-verbal); intellectual disability in the moderate to severe range; mild hypotonia in infancy followed by spastic diplegia (mean age: 8.4 +/- 5.1 years, SD) and later tetraplegia (mean age: 16.1 +/- 9.8 years, SD); postnatal microcephaly (83%); foot deformities (69%); and epilepsy (66%) that is intractable in a subset. At last follow-up, 36% ambulated with assistance (mean age: 8.9 +/- 6.4 years, SD) and 54% were wheelchair-dependent (mean age: 13.4 +/- 9.8 years, SD). Episodes of stereotypic laughing, possibly consistent with a pseudobulbar affect, were found in 56% of patients. Key features on neuroimaging include a thin corpus callosum (90%), ventriculomegaly (65%) often with colpocephaly, and periventricular white-matter signal abnormalities (68%). Iron deposition and polymicrogyria were found in a subset of patients. AP4B1-associated SPG47 and AP4M1-associated SPG50 accounted for the majority of cases. About two-thirds of patients were born to consanguineous parents, and 82% carried homozygous variants. Over 70 unique variants were present, the majority of which are frameshift or nonsense mutations. To track disease progression across the age spectrum, we defined the relationship between disease severity as measured by several rating scales and disease duration. We found that the presence of epilepsy, which manifested before the age of 3 years in the majority of patients, was associated with worse motor outcomes. Exploring genotype-phenotype correlations, we found that disease severity and major phenotypes were equally distributed among the four subtypes, establishing that SPG47, SPG50, SPG51 and SPG52 share a common phenotype, an 'AP-4 deficiency syndrome'. By delineating the core clinical, imaging, and molecular features of AP-4-associated hereditary spastic paraplegia across the age spectrum our results will facilitate early diagnosis, enable counselling and anticipatory guidance of affected families and help define endpoints for future interventional trials.
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| 6. |
- Engler, Henry, et al.
(författare)
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Two-year follow-up of amyloid deposition in patients with Alzheimer's disease
- 2006
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Ingår i: Brain. - : Oxford University Press (OUP). - 0006-8950 .- 1460-2156. ; 129:Pt 11, s. 2856-2866
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Tidskriftsartikel (refereegranskat)abstract
- Beta amyloid is one of the major histopathological hallmarks of Alzheimer's disease. We recently reported in vivo imaging of amyloid in 16 Alzheimer patients, using the PET ligand N-methyl[11C]2-(4'-methylaminophenyl)-6-hydroxy-benzothiazole (PIB). In the present study we rescanned these 16 Alzheimer patients after 2.0 +/- 0.5 years and have described the interval change in amyloid deposition and regional cerebral metabolic rate for glucose (rCMRGlc) at follow-up. Sixteen patients with Alzheimer's disease were re-examined by means of PET, using PIB and 2-[18F]fluoro-2-deoxy-d-glucose (FDG) after 2.0 +/- 0.5 years. The patients were all on cholinesterase inhibitor treatment and five also on treatment with the N-methyl-d-aspartate (NMDA) antagonist memantine. In order to estimate the accuracy of the PET PIB measurements, four additional Alzheimer patients underwent repeated examinations with PIB within 20 days (test-retest). Relative PIB retention in cortical regions differed by 3-7% in the test-retest study. No significant difference in PIB retention was observed between baseline and follow-up while a significant (P < 0.01) 20% decrease in rCMRGlc was observed in cortical brain regions. A significant negative correlation between rCMRGlc and PIB retention was observed in the parietal cortex in the Alzheimer patients at follow-up (r = 0.67, P = 0.009). A non-significant decline in Mini-Mental State Examination (MMSE) score from 24.3 +/- 3.7 (mean +/- standard deviation) to 22.7 +/- 6.1 was measured at follow-up. Five of the Alzheimer patients showed a significant decline in MMSE score of >3 (21.4 +/- 3.5 to 15.6 +/- 3.9, P < 0.01) (AD-progressive) while the rest of the patients were cognitively more stable (MMSE score = 25.6 +/- 3.1 to 25.9 +/- 3.7) (AD-stable) compared with baseline. A positive correlation (P = 0.001) was observed in the parietal cortex between Rey Auditory Verbal Learning (RAVL) test score and rCMRGlc at follow-up while a negative correlation (P = 0.018) was observed between RAVL test and PIB retention in the parietal at follow-up. Relatively stable PIB retention after 2 years of follow-up in patients with mild Alzheimer's disease suggests that amyloid deposition in the brain reaches a plateau by the early clinical stages of Alzheimer's disease and therefore may precede a decline in rCMRGlc and cognition. It appears that anti-amyloid therapies will need to induce a significant decrease in amyloid load in order for PIB PET images to detect a drug effect in Alzheimer patients. FDG imaging may be able to detect a stabilization of cerebral metabolism caused by therapy administered to patients with a clinical diagnosis of Alzheimer's disease.
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| 7. |
- Fang, Fang, et al.
(författare)
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Suicide among patients with amyotrophic lateral sclerosis
- 2008
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Ingår i: Brain. - Oxford, United Kingdom : Oxford University Press (OUP). - 0006-8950 .- 1460-2156. ; 131, s. 2729-2733
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Tidskriftsartikel (refereegranskat)abstract
- Studies on the suicide risk among patients with amyotrophic lateral sclerosis (ALS) in countries without legalized euthanasia or assisted suicide are important additions to data on the wish to die of these patients. We conducted a population-based cohort study in Sweden between 1965 and 2004, which comprised of 6642 patients with incident ALS identified from the Swedish Inpatient Register. We calculated the standardized mortality ratios (SMRs) of suicide among the patients using the suicide rates of the general Swedish population as a reference. In total, 21 patients committed suicide during follow-up, compared to the predicted 3.6 suicides. Thus, we noted an almost 6-fold increased risk for suicide among ALS patients [SMR 5.8, 95% confidence interval (CI) 3.6-8.8]. Patients who committed suicide were, on average, around 7 years younger at the time of their first period of hospitalization than patients who did not commit suicide. The highest relative risk for suicide was observed within the first year after the patients first period of hospitalization (SMR 11.2, 95% CI 5.8-19.6). After that, the relative risks decreased with time after hospitalization (P-value for trend = 0.006), but remained elevated 3 years later. The relative risks of suicide among ALS patients did not show a clear trend over time in contrast to the decreasing trend of relative risks for suicide among patients with cancer during the same period. Patients with ALS are at excess risk of suicide in Sweden and the relative risk is higher during the earlier stage of the disease.
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| 8. |
- Ferrucci, Veronica, et al.
(författare)
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Metastatic group 3 medulloblastoma is driven by PRUNE1 targeting NME1–TGF-β–OTX2–SNAIL via PTEN inhibitio
- 2018
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Ingår i: Brain. - : Oxford University Press (OUP). - 0006-8950 .- 1460-2156. ; 141:5, s. 1300-1319
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Tidskriftsartikel (refereegranskat)abstract
- Genetic modifications during development of paediatric groups 3 and 4 medulloblastoma are responsible for their highly metastatic properties and poor patient survival rates. PRUNE1 is highly expressed in metastatic medulloblastoma group 3, which is characterized by TGF-β signalling activation, c-MYC amplification, and OTX2 expression. We describe the process of activation of the PRUNE1 signalling pathway that includes its binding to NME1, TGF-β activation, OTX2 upregulation, SNAIL (SNAI1) upregulation, and PTEN inhibition. The newly identified small molecule pyrimido-pyrimidine derivative AA7.1 enhances PRUNE1 degradation, inhibits this activation network, and augments PTEN expression. Both AA7.1 and a competitive permeable peptide that impairs PRUNE1/NME1 complex formation, impair tumour growth and metastatic dissemination in orthotopic xenograft models with a metastatic medulloblastoma group 3 cell line (D425-Med cells). Using whole exome sequencing technology in metastatic medulloblastoma primary tumour cells, we also define 23 common ‘non-synonymous homozygous’ deleterious gene variants as part of the protein molecular network of relevance for metastatic processes. This PRUNE1/TGF-β/OTX2/PTEN axis, together with the medulloblastoma-driver mutations, is of relevance for future rational and targeted therapies for metastatic medulloblastoma group 3.
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| 9. |
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| 10. |
- Ibanez, L., et al.
(författare)
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Multi-ancestry GWAS reveals excitotoxicity associated with outcome after ischaemic stroke
- 2022
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Ingår i: Brain. - : Oxford University Press (OUP). - 0006-8950 .- 1460-2156. ; 145:7, s. 2394-2406
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Tidskriftsartikel (refereegranskat)abstract
- During the first hours after stroke onset, neurological deficits can be highly unstable: some patients rapidly improve, while others deteriorate. This early neurological instability has a major impact on long-term outcome. Here, we aimed to determine the genetic architecture of early neurological instability measured by the difference between the National Institutes of Health Stroke Scale (NIHSS) within 6 h of stroke onset and NIHSS at 24 h. A total of 5876 individuals from seven countries (Spain, Finland, Poland, USA, Costa Rica, Mexico and Korea) were studied using a multi-ancestry meta-analyses. We found that 8.7% of NIHSS at 24 h of variance was explained by common genetic variations, and also that early neurological instability has a different genetic architecture from that of stroke risk. Eight loci (1p21.1, 1q42.2, 2p25.1, 2q31.2, 2q33.3, 5q33.2, 7p21.2 and 13q31.1) were genome-wide significant and explained 1.8% of the variability suggesting that additional variants influence early change in neurological deficits. We used functional genomics and bioinformatic annotation to identify the genes driving the association from each locus. Expression quantitative trait loci mapping and summary data-based Mendelian randomization indicate that ADAM23 (log Bayes factor = 5.41) was driving the association for 2q33.3. Gene-based analyses suggested that GRIA1 (log Bayes factor = 5.19), which is predominantly expressed in the brain, is the gene driving the association for the 5q33.2 locus. These analyses also nominated GNPAT (log Bayes factor = 7.64) ABCB5 (log Bayes factor = 5.97) for the 1p21.1 and 7p21.1 loci. Human brain single-nuclei RNA-sequencing indicates that the gene expression of ADAM23 and GRIA1 is enriched in neurons. ADAM23, a presynaptic protein and GRIA1, a protein subunit of the AMPA receptor, are part of a synaptic protein complex that modulates neuronal excitability. These data provide the first genetic evidence in humans that excitotoxicity may contribute to early neurological instability after acute ischaemic stroke. Ibanez et al. perform a multi-ancestry meta-analysis to investigate the genetic architecture of early stroke outcomes. Two of the eight genome-wide significant loci identified-ADAM23 and GRIA1-are involved in synaptic excitability, suggesting that excitotoxicity contributes to neurological instability after ischaemic stroke.
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