| 1. |
- Herukka, Sanna-Kaisa, et al.
(författare)
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Amyloid-beta and Tau Dynamics in Human Brain Interstitial Fluid in Patients with Suspected Normal Pressure Hydrocephalus
- 2015
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Ingår i: Journal of Alzheimer's Disease. - 1387-2877 .- 1875-8908. ; 46:1, s. 261-269
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Tidskriftsartikel (refereegranskat)abstract
- Background: Amyloid-beta (A beta(1-42)), total tau (T-tau), and phosphorylated tau (P-tau(181)) in the cerebrospinal fluid (CSF) are the most promising biomarkers of Alzheimer's disease (AD). Still, little is known about the dynamics of these molecules in the living brain. In a transgenic mouse brain, soluble A beta decreases with increasing age and advanced A beta pathology as seen similarly in CSF. Objective: To assess the relationship between AD-related pathological changes in human brain tissue, ventricular and lumbar CSF, and brain interstitial fluid (ISF). Methods: Altogether 11 patients with suspected idiopathic normal pressure hydrocephalus underwent frontal cortical brain biopsy, 24-h intraventricular pressure monitoring, and a microdialysis procedure. AD-related biomarkers were analyzed from brain tissue, CSF, and ISF. Results: ISF T-tau levels decreased strongly within the first 12 h, then plateauing until the end of the experiment. A beta(1-42) and P-tau(181) remained stable during the experiment (n = 3). T-tau and P-tau were higher in the ISF than in ventricular or lumbar CSF, while A beta(1-42) levels were within similar range in both CSF and ISF samples. ISF P-tau correlated with the ventricular CSF T-tau (r = 0.70, p = 0.017) and P-tau(181) (r = 0.64, p = 0.034). Five patients with amyloid pathology in the brain biopsy tended to reveal lower ISF A beta(1-42) levels than those six without amyloid pathology. Conclusions: This is the first study to report ISF A beta and tau levels in the human brain without significant brain injury. The set-up used enables sampling from the brain ISF for at least 24 h without causing adverse effects due to the microdialysis procedure to follow the dynamics of the key molecules in AD pathogenesis in the living brain at various stages of the disease.
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| 2. |
- Laitera, Tiina, et al.
(författare)
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The Expression of Transthyretin and Amyloid-beta Protein Precursor is Altered in the Brain of Idiopathic Normal Pressure Hydrocephalus Patients
- 2015
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Ingår i: Journal of Alzheimer's Disease. - 1387-2877 .- 1875-8908. ; 48:4, s. 959-968
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Tidskriftsartikel (refereegranskat)abstract
- Background: Idiopathic normal pressure hydrocephalus (iNPH) is a dementing condition in which Alzheimer's disease (AD)related amyloid-beta (A beta) plaques are frequently observed in the neocortex. iNPH patients with prominent A beta pathology show AD-related alterations in amyloid-beta protein precursor (A beta PP) processing resulting from increased gamma-secretase activity. Objectives: Our goal was to assess potential alterations in the global gene expression profile in the brain of iNPH patients as compared to non-demented controls and to evaluate the levels of the identified targets in the cerebrospinal fluid (CSF) of iNPH patients. Methods: The genome-wide expression profile of similar to 35,000 probes was assessed in the RNA samples obtained from 22 iNPH patients and eight non-demented control subjects using a microarray chip. The soluble levels of sA beta PP alpha, sA beta PP beta, and transthyretin (TTR) were measured from the CSF of 102 iNPH patients using ELISA. Results: After correcting the results for multiple testing, significant differences in the expression of TTR and A beta PP were observed between iNPH and control subjects. The mRNA levels of TTR were on average 17-fold lower in iNPH samples compared to control samples. Conversely, the expression level of A beta PP was on average three times higher in iNPH samples as compared to control samples. Interestingly, the expression of beta-secretase (ADAM10) was also increased in iNPH patients. In the lumbar CSF samples, soluble TTR levels showed a significant positive correlation with sA beta PP alpha and sA beta PP beta, but TTR levels did not predict the brain pathology or the shunt response. Conclusions: These findings suggest differences in the expression profile of key factors involved in AD-related cellular events in the brain of iNPH patients.
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| 3. |
- Laiterä, Tiina, et al.
(författare)
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Effects of Alzheimer's Disease-Associated Risk Loci on Amyloid-β Accumulation in the Brain of Idiopathic Normal Pressure Hydrocephalus Patients
- 2017
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Ingår i: Journal of Alzheimer's Disease. - 1387-2877 .- 1875-8908. ; 55:3, s. 995-1003
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Idiopathic normal pressure hydrocephalus (iNPH) is a dementing condition featuring characteristic symptoms, ventriculomegaly, and normal or slightly elevated cerebrospinal fluid pressure. In Alzheimer's disease (AD) patients, diffuse aggregates of amyloid-β (Aβ) and neurofibrillary hyperphosphorylated tau are detected in the neocortex of the brain, while similar accumulation of Aβ is also detected in iNPH. Recent genome-wide association studies have identified several novel risk loci for AD, potentially affecting Aβ-related cellular processes. Apart from the apolipoprotein E ɛ4 allele (APOE4), the risk effect of single loci is low, emphasizing the importance of the polygenic risk score approach when assessing the combined effects.OBJECTIVE: To study the effects of AD-associated individual and polygenic risk score of single nucleotide polymorphisms (SNPs) on the accumulation of Aβ in the brain samples of iNPH patients.METHODS: A sample set of frontal cortex biopsies from 188 iNPH patients were divided into two groups according to the Aβ pathology. After the genotyping of the AD-associated risk loci, polygenic risk score was calculated for each iNPH patient and subsequently analyzed in relation to Aβ deposition.RESULTS: Apart from the APOE4, none of the SNPs revealed a statistically significant effect on the accumulation of Aβ in iNPH. Also, the non-APOE4 polygenic risk score did not associate with Aβ deposition.CONCLUSION: Novel AD-associated risk genes have no significant effect on Aβ accumulation in the brain of iNPH patients. However, APOE4 affects the Aβ deposition in the brain of iNPH and AD patients in a similar manner.
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| 4. |
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| 5. |
- Luikku, Antti J., et al.
(författare)
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Multimodal analysis to predict shunt surgery outcome of 284 patients with suspected idiopathic normal pressure hydrocephalus
- 2016
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Ingår i: Acta Neurochirurgica. - : Springer Science and Business Media LLC. - 0001-6268 .- 0942-0940. ; 158:12, s. 2311-2319
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Tidskriftsartikel (refereegranskat)abstract
- Optimal selection of idiopathic normal pressure hydrocephalus (iNPH) patients for shunt surgery is challenging. Disease State Index (DSI) is a statistical method that merges multimodal data to assist clinical decision-making. It has previously been shown to be useful in predicting progression in mild cognitive impairment and differentiating Alzheimer's disease (AD) and frontotemporal dementia. In this study, we use the DSI method to predict shunt surgery response for patients with iNPH. In this retrospective cohort study, a total of 284 patients (230 shunt responders and 54 non-responders) from the Kuopio NPH registry were analyzed with the DSI. Analysis included data from patients' memory disorder assessments, age, clinical symptoms, comorbidities, medications, frontal cortical biopsy, CT/MRI imaging (visual scoring of disproportion between Sylvian and suprasylvian subarachnoid spaces, atrophy of medial temporal lobe, superior medial subarachnoid spaces), APOE genotyping, CSF AD biomarkers, and intracranial pressure. Our analysis showed that shunt responders cannot be differentiated from non-responders reliably even with the large dataset available (AUC = 0.58). Prediction of the treatment response in iNPH is challenging even with our extensive dataset and refined analysis. Further research of biomarkers and indicators predicting shunt responsiveness is still needed.
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| 6. |
- Luikku, Antti J., et al.
(författare)
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Predicting Development of Alzheimer's Disease in Patients with Shunted Idiopathic Normal Pressure Hydrocephalus
- 2019
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Ingår i: Journal of Alzheimer's Disease. - 1387-2877 .- 1875-8908. ; 71:4, s. 1233-1243
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Tidskriftsartikel (refereegranskat)abstract
- Background: Idiopathic normal pressure hydrocephalus (iNPH) patients often develop Alzheimer's disease (AD) related brain pathology. Disease State Index (DSI) is a method to combine data from various sources for differential diagnosis and progression of neurodegenerative disorders.Objective: To apply DSI to predict clinical AD in shunted iNPH-patients in a defined population.Methods: 335 shunted iNPH-patients (median 74 years) were followed until death (n = 185) or 6/2015 (n = 150). DSI model (including symptom profile, onset age of NPH symptoms, atrophy of medial temporal lobe in CT/MRI, cortical brain biopsy finding, and APOE genotype) was applied. Performance of DSI model was evaluated with receiver operating characteristic (ROC) curve analysis.Results: A total of 70 (21%) patients developed clinical AD during median follow-up of 5.3 years. DSI-model predicted clinical AD with moderate effectiveness (AUC= 0.75). Significant factors were cortical biopsy (0.69), clinical symptoms (0.66), and medial temporal lobe atrophy (0.66).Conclusion: We found increased occurrence of clinical AD in previously shunted iNPH patients as compared with general population. DSI supported the prediction of AD. Cortical biopsy during shunt insertion seems indicated for earlier diagnosis of comorbid AD.
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| 7. |
- Martiskainen, Henna, et al.
(författare)
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Transcriptomics and mechanistic elucidation of Alzheimer's disease risk genes in the brain and in vitro models
- 2015
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Ingår i: Neurobiology of Aging. - : Elsevier BV. - 0197-4580 .- 1558-1497. ; 36:2, s. 1221e15-1221e28
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Tidskriftsartikel (refereegranskat)abstract
- In this study, we have assessed the expression and splicing status of genes involved in the pathogenesis or affecting the risk of Alzheimer's disease (AD) in the postmortem inferior temporal cortex samples obtained from 60 subjects with varying degree of AD-related neurofibrillary pathology. These subjects were grouped based on neurofibrillary pathology into 3 groups: Braak stages 0-II, Braak stages III-IV, and Braak stages V-VI. We also examined the right frontal cortical biopsies obtained during life from 22 patients with idiopathic shunt-responding normal pressure hydrocephalus, a disease that displays similar pathologic alterations as seen in AD. These 22 patients were categorized according to dichotomized amyloid-β positive or negative pathology in the biopsies. We observed that the expression of FRMD4A significantly decreased, and the expression of MS4A6A significantly increased in relation to increasing AD-related neurofibrillary pathology. Moreover, the expression of 2 exons in both CLU and TREM2 significantly increased with increase in AD-related neurofibrillary pathology. However, a similar trend toward increased expression in CLU and TREM2 was observed with most of the studied exons, suggesting a global change in the expression rather than altered splicing. Correlation of gene expression with well-established AD-related factors, such as α-, β-, and γ-secretase activities, brain amyloid-β42 levels, and cerebrospinal fluid biomarkers, revealed a positive correlation between β-secretase activity and the expression of TREM2 and BIN1. In expression quantitative trait loci analysis, we did not detect significant effects of the risk alleles on gene expression or splicing. Analysis of the normal pressure hydrocephalus biopsies revealed no differences in the expression or splicing profiles of the studied genes between amyloid-β positive and negative patients. Using the protein-protein interaction-based in vitro pathway analysis tools, we found that downregulation of FRMD4A associated with increased APP-β-secretase interaction, increased amyloid-β40 secretion, and altered phosphorylation of tau. Taken together, our results suggest that the expression of FRMD4A, MS4A6A, CLU, and TREM2 is altered in relation to increasing AD-related neurofibrillary pathology, and that FRMD4A may play a role in amyloidogenic and tau-related pathways in AD. Therefore, investigation of gene expression changes in the brain and effects of the identified genes on disease-associated pathways in vitro may provide mechanistic insights on how alterations in these genes may contribute to AD pathogenesis.
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| 8. |
- Solomon, Alina, et al.
(författare)
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Effect of the Apolipoprotein E Genotype on Cognitive Change During a Multidomain Lifestyle Intervention A Subgroup Analysis of a Randomized Clinical Trial
- 2018
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Ingår i: JAMA Neurology. - : American Medical Association (AMA). - 2168-6149 .- 2168-6157. ; 75:4, s. 462-470
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Tidskriftsartikel (refereegranskat)abstract
- IMPORTANCE The role of the apolipoprotein E (APOE) epsilon 4 allele as an effect modifier in lifestyle interventions to prevent cognitive impairment is still unclear. OBJECTIVE To examine whether the APOE epsilon 4 allele modifies the previously reported significant cognitive benefits of a multidomain lifestyle intervention (prespecified subgroup analysis). DESIGN, SETTING, AND PARTICIPANTS The Finnish Geriatric Intervention Study to Prevent Cognitive Impairment and Disability (FINGER) was a randomized clinical trial in 6 centers across Finland (screening and randomization performed from September 7, 2009, through November 24, 2011; intervention duration, 2 years). Data analysis was performed from August 1, 2015, to March 31, 2016. The study population was at-risk older individuals from the general population. Inclusion criteria were age of 60 to 77 years; Cardiovascular Risk Factors, Aging, and Dementia risk score of at least 6 points; and cognition at a mean level or slightly lower than expected for age. Individuals with dementia or substantial cognitive impairment and conditions that prevented cooperation or safe engagement in the intervention were excluded. APOE genotype data were available for 1175 of the 1260 participants. INTERVENTIONS Participants were randomly assigned in a 1: 1 ratio to a multidomain intervention group (diet, exercise, cognitive training, and vascular risk management) or a control group (general health advice). Group allocation was not actively disclosed to participants, and outcome assessors were masked to group allocation. MAIN OUTCOMES AND MEASURES Primary outcome was change in cognition measured through a comprehensive neuropsychological test battery. Analysis was based on modified intention to treat (participants with at least 1 postbaseline assessment). RESULTS A total of 1109 participants (mean [SD] age, 69.3 [4.7] years; 514 [46.3%] female) were included in the analysis: 362 APOE epsilon 4 allele carriers (173 intervention and 189 control) and 747 noncarriers (380 intervention and 367 control). The APOE epsilon 4 carriers and noncarriers were not significantly different at baseline (except for serum cholesterol level). The difference between the intervention and control groups in annual neuropsychological test battery total score change was 0.037 (95% CI, 0.001 to 0.073) among carriers and 0.014 (95% CI, -0.011 to 0.039) among noncarriers. Intervention effect was not significantly different between carriers and noncarriers (0.023; 95% CI, -0.021 to 0.067). CONCLUSIONS AND RELEVANCE Healthy lifestyle changesmay be beneficial for cognition in older at-risk individuals even in the presence of APOE-related genetic susceptibility to dementia. Whether such benefits are more pronounced in APOE epsilon 4 carriers compared with noncarriers should be further investigated. The findings also emphasize the importance of early prevention strategies that target multiple modifiable risk factors simultaneously.
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