| 1. |
- Jack, C. R., et al.
(författare)
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Magnetic resonance imaging in Alzheimer's Disease Neuroimaging Initiative 2
- 2015
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Ingår i: Alzheimers & Dementia. - : Wiley. - 1552-5260 .- 1552-5279. ; 11:7, s. 740-756
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Tidskriftsartikel (refereegranskat)abstract
- Introduction: Alzheimer's Disease Neuroimaging Initiative (ADNI) is now in its 10th year. The primary objective of the magnetic resonance imaging (MRI) core of ADNI has been to improve methods for clinical trials in Alzheimer's disease (AD) and related disorders. Methods: We review the contributions of the MRI core from present and past cycles of ADNI (ADNI-1, -Grand Opportunity and -2). We also review plans for the future-ADNI-3. Results: Contributions of the MRI core include creating standardized acquisition protocols and quality control methods; examining the effect of technical features of image acquisition and analysis on outcome metrics; deriving sample size estimates for future trials based on those outcomes; and piloting the potential utility of MR perfusion, diffusion, and functional connectivity measures in multicenter clinical trials. Discussion: Over the past decade the MRI core of ADNI has fulfilled its mandate of improving methods for clinical trials in AD and will continue to do so in the future. (C) 2015 The Authors. Published by Elsevier Inc. on behalf of the Alzheimer's Association.
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| 2. |
- Insel, P. S., et al.
(författare)
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Biomarkers and cognitive endpoints to optimize trials in Alzheimer's disease
- 2015
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Ingår i: Annals of Clinical and Translational Neurology. - : Wiley. - 2328-9503. ; 2:5, s. 534-547
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Tidskriftsartikel (refereegranskat)abstract
- Objective: To find the combination of candidate biomarkers and cognitive endpoints to maximize statistical power and minimize cost of clinical trials of healthy elders at risk for cognitive decline due to Alzheimer's disease. Methods: Four-hundred and twelve cognitively normal participants were followed over 7 years. Nonlinear methods were used to estimate the longitudinal trajectories of several cognitive outcomes including delayed memory recall, executive function, processing speed, and several cognitive composites by subgroups selected on the basis of biomarkers, including APOE-epsilon 4 allele carriers, cerebrospinal fluid biomarkers (A beta(42), total tau, and phosphorylated tau), and those with small hippocampi. Results: Derived cognitive composites combining Alzheimer's Disease Assessment Scale (ADAS)-cog scores with additional delayed memory recall and executive function components captured decline more robustly across biomarker groups than any measure of a single cognitive domain or ADAS-cog alone. Substantial increases in power resulted when including only participants positive for three or more biomarkers in simulations of clinical trials. Interpretation: Clinical trial power may be improved by selecting participants on the basis of amyloid and neurodegeneration biomarkers and carefully tailoring primary cognitive endpoints to reflect the expected decline specific to these individuals.
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| 3. |
- Insel, P. S., et al.
(författare)
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The transitional association between beta-amyloid pathology and regional brain atrophy
- 2015
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Ingår i: Alzheimers & Dementia. - : Wiley. - 1552-5260 .- 1552-5279. ; 11:10, s. 1171-1179
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Tidskriftsartikel (refereegranskat)abstract
- Introduction: Alzheimer's disease (AD) is characterized by the accumulation of beta-amyloid (A beta) associated with brain atrophy and cognitive decline. The functional form to model the association between A beta and regional brain atrophy has not been well defined. To determine the relationship between Ab and atrophy, we compared the performance of the usual dichotomization of cerebrospinal fluid (CSF) A beta to identify subjects as A beta+ and A beta- with a trilinear spline model of CSF A beta. Methods: One hundred and eighty-three subjects with mild cognitive impairment and 108 cognitively normal controls with baseline CSFA beta and up to 4 years of longitudinal magnetic resonance imaging data from the Alzheimer's Disease Neuroimaging Initiative were analyzed using mixed-effects regression. Piecewise-linear splines were used to evaluate the nonlinear nature of the association between CSF A beta and regional atrophy and to identify points of acceleration of atrophy with respect to A beta. Several parameterizations of CSFA beta were compared using likelihood ratio tests and the Akaike information criterion. Periods of acceleration of atrophy in which subjects transition from CSF A beta negativity to CSFA beta positivity were estimated from the spline models and tested for significance. Results: Spline models resulted in better fits for many temporal and parietal regions compared with the dichotomous models. The trilinear model showed that periods of acceleration of atrophy varied greatly by region with early changes seen in the insula, amygdala, precuneus, hippocampus, and other temporal regions, occurring before the clinical threshold for CSF A beta positivity. Discussion: The use of piecewise-linear splines provides an improved model of the nonlinear association between CSF A beta and regional atrophy in regions implicated in the progression of AD. The important biological finding of this work is that some brain regions show periods of accelerated volume loss well before the CSFA beta(42) threshold. This implies that signs of brain atrophy develop before the current conventional definition of "preclinical AD". (C) 2015 The Alzheimer's Association. Published by Elsevier Inc. All rights reserved.
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| 4. |
- Mattsson, Niklas, 1979, et al.
(författare)
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Brain structure and function as mediators of the effects of amyloid on memory
- 2015
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Ingår i: Neurology. - : Ovid Technologies (Wolters Kluwer Health). - 0028-3878 .- 1526-632X. ; 84:11, s. 1136-1144
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Tidskriftsartikel (refereegranskat)abstract
- Objective:The objective of this study was to test whether effects of -amyloid (A) pathology on episodic memory were mediated by metabolism and gray matter volume in the early stages of Alzheimer disease.Methods:This was a prospective cohort study. We measured baseline A (using florbetapir-PET), brain function (using fluorodeoxyglucose-PET), and brain structure (using MRI). A mediation analysis was performed to test whether statistical effects of A positivity on cross-sectional and longitudinal episodic memory were mediated by hypometabolism or regional gray matter volume in cognitively healthy controls (CN, n = 280) and mild cognitive impairment (MCI, n = 463).Results:Lower memory scores were associated with A positivity (CN, mildly; MCI, strongly), smaller gray matter volumes (CN, few regions, including hippocampus; MCI, widespread), and hypometabolism. Smaller volumes and hypometabolism mediated effects of A in MCI but not in CN. The strongest individual regions mediated up to approximately 25%. A combination of brain structure and function mediated up to approximately 40%. In several regions, gray matter atrophy and hypometabolism predicted episodic memory without being associated (at p < 0.05) with A positivity.Conclusions:Changes in brain structure and function appear to be, in part, downstream events from A pathology, ultimately resulting in episodic memory deficits. However, A pathology is also strongly related to memory deficits through mechanisms that are not quantified by these imaging measurements, and episodic memory decline is partly caused by Alzheimer disease-like brain changes independently of A pathology.
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| 5. |
- Mattsson, Niklas, 1979, et al.
(författare)
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Predicting Reduction of Cerebrospinal Fluid beta-Amyloid 42 in Cognitively Healthy Controls
- 2015
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Ingår i: Jama Neurology. - : American Medical Association (AMA). - 2168-6149. ; 72:5, s. 554-560
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Tidskriftsartikel (refereegranskat)abstract
- IMPORTANCE Alzheimer disease has a long preclinical stage characterized by beta-amyloid (A beta) accumulation without symptoms. Several trials focus on this stage and use biomarkers to include A beta-positive participants, but an even earlier prevention of A beta accumulation may be an effective treatment strategy. OBJECTIVE To determine whether people who appear to be A beta negative but are at high risk for A beta positivity within the near future can be identified. DESIGN, SETTING, AND PARTICIPANTS Longitudinal biomarker cohort study involving 35 cognitively healthy individuals who underwent cerebrospinal fluid (CSF) sampling for up to 3 years during the study (October 24, 2005, to September 1, 2014). All participants had normal CSF A beta 42 levels at baseline. MAIN OUTCOMES AND MEASURES Predictors of future A beta positivity (levels of CSF A beta 42 declining below a previously validated cutoff level of 192 ng/L) tested by random forest models. Tested predictors included levels of protein in the CSF, hippocampal volume, genetics, demographics, and cognitive scores. RESULTS The CSF A beta 42 levels declined in 11 participants, and the CSF became A beta positive. The baseline CSF A beta 42 level was a strong predictor of future positivity (accuracy, 79% [95% CI, 70%-87%]). Ten of 11 decliners had baseline CSF A beta 42 levels in the lower tertile of the reference range (<225 ng/L), and 22 of 24 nondecliners had baseline CSF A beta 42 levels in the upper 2 tertiles (similar to 225 ng/L). A high CSF P-tau level was associated with decline (accuracy, 68%; 95% CI, 55%-81%). CONCLUSIONS AND RELEVANCE Baseline CSF A beta 42 levels in the lower part of the reference range are strongly associated with future A beta positivity. This finding can be used in trials on very early prevention of Alzheimer disease to identify people at high risk for Ab accumulation as defined by low CSF A beta 42 levels.
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| 6. |
- Sacuiu, Simona, 1971, et al.
(författare)
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Chronic Depressive Symptomatology in Mild Cognitive Impairment Is Associated with Frontal Atrophy Rate which Hastens Conversion to Alzheimer Dementia
- 2016
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Ingår i: American Journal of Geriatric Psychiatry. - : Elsevier BV. - 1064-7481. ; 24:2, s. 126-135
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Tidskriftsartikel (refereegranskat)abstract
- Objective: Investigate the association of chronic depressive symptomatology (chrDS) with cortical atrophy rates and conversion to Alzheimer dementia (AD) over 3 years in mild cognitive impairment (MCI). Methods: In a multicenter, clinic-based study, MCI elderly participants were selected from the Alzheimer's Disease Neuroimaging Initiative repository, based on availability of both serial structural magnetic resonance imaging and chrDS endorsed on three depression-related items from the Neuropsychiatric Inventory Questionnaire (chrDS N = 32 or no depressive symptoms N = 62) throughout follow-up. Clinical and laboratory investigations were performed every 6 months during the first 2 years and yearly thereafter (median follow-up: 3 years; interquartile range: 1.5-4.0 years). Cortical atrophy rates in 16 predefined frontotemporoparietal regions affected in major depression and AD and the rate of incident AD at follow-up. Results: ChrDS in a single domain amnestic MCI sample were associated with accelerated cortical atrophy in the frontal lobe and anterior cingulate but not with atrophy rates in temporomedial or other AD-affected regions. During follow-up, 38 participants (42.7%) developed AD. Participants with chrDS had 60% shorter conversion time to AD than those without depressive symptoms. This association remained significant in survival models adjusted for temporomedial atrophy rates and showed the same trend in models adjusted for frontal cortical atrophy rate, which all increased the risk of AD. Conclusion: Our results suggest that chrDS associated with progressive atrophy of frontal regions may represent an additional risk factor for conversion to dementia in MCI as opposite to representing typical prodromal AD symptomatology.
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| 7. |
- Skyler, Jay S, et al.
(författare)
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Differentiation of diabetes by pathophysiology, natural history, and prognosis
- 2017
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Ingår i: Diabetes. - : American Diabetes Association. - 0012-1797 .- 1939-327X. ; 66:2, s. 241-255
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Forskningsöversikt (refereegranskat)abstract
- The American Diabetes Association, JDRF, the European Association for the Study of Diabetes, and the American Association of Clinical Endocrinologists convened a research symposium, "The Differentiation of Diabetes by Pathophysiology, Natural History and Prognosis" on 10-12 October 2015. International experts in genetics, immunology, metabolism, endocrinology, and systems biology discussed genetic and environmental determinants of type 1 and type 2 diabetes risk and progression, as well as complications. The participants debated how to determine appropriate therapeutic approaches based on disease pathophysiology and stage and defined remaining research gaps hindering a personalized medical approach for diabetes to drive the field to address these gaps. The authors recommend a structure for data stratification to define the phenotypes and genotypes of subtypes of diabetes that will facilitate individualized treatment.
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| 8. |
- Ewart, L, et al.
(författare)
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Application of Microphysiological Systems to Enhance Safety Assessment in Drug Discovery
- 2018
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Ingår i: Annual review of pharmacology and toxicology. - : Annual Reviews. - 1545-4304 .- 0362-1642. ; 58, s. 65-82
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Tidskriftsartikel (refereegranskat)abstract
- Enhancing the early detection of new therapies that are likely to carry a safety liability in the context of the intended patient population would provide a major advance in drug discovery. Microphysiological systems (MPS) technology offers an opportunity to support enhanced preclinical to clinical translation through the generation of higher-quality preclinical physiological data. In this review, we highlight this technological opportunity by focusing on key target organs associated with drug safety and metabolism. By focusing on MPS models that have been developed for these organs, alongside other relevant in vitro models, we review the current state of the art and the challenges that still need to be overcome to ensure application of this technology in enhancing drug discovery.
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| 9. |
- Insel, Philip S., et al.
(författare)
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Accelerating rates of cognitive decline and imaging markers associated with β-amyloid pathology
- 2016
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Ingår i: Neurology. - 0028-3878. ; 86:20, s. 1887-1896
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Tidskriftsartikel (refereegranskat)abstract
- Objective: To estimate points along the spectrum of β-amyloid pathology at which rates of change of several measures of neuronal injury and cognitive decline begin to accelerate. Methods: In 460 patients with mild cognitive impairment (MCI), we estimated the points at which rates of florbetapir PET, fluorodeoxyglucose (FDG) PET, MRI, and cognitive and functional decline begin to accelerate with respect to baseline CSF Aβ 42. Points of initial acceleration in rates of decline were estimated using mixed-effects regression. Results: Rates of neuronal injury and cognitive and even functional decline accelerate substantially before the conventional threshold for amyloid positivity, with rates of florbetapir PET and FDG PET accelerating early. Temporal lobe atrophy rates also accelerate prior to the threshold, but not before the acceleration of cognitive and functional decline. Conclusions: A considerable proportion of patients with MCI would not meet inclusion criteria for a trial using the current threshold for amyloid positivity, even though on average, they are experiencing cognitive/functional decline associated with prethreshold levels of CSF Aβ 42. Future trials in early Alzheimer disease might consider revising the criteria regarding β-amyloid thresholds to include the range of amyloid associated with the first signs of accelerating rates of decline. © 2016 American Academy of Neurology.
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| 10. |
- Insel, Richard A, et al.
(författare)
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Staging Presymptomatic Type 1 Diabetes: A Scientific Statement of JDRF, the Endocrine Society, and the American Diabetes Association.
- 2015
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Ingår i: Diabetes Care. - : American Diabetes Association. - 1935-5548 .- 0149-5992. ; 38:10, s. 1964-1974
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Tidskriftsartikel (refereegranskat)abstract
- Insights from prospective, longitudinal studies of individuals at risk for developing type 1 diabetes have demonstrated that the disease is a continuum that progresses sequentially at variable but predictable rates through distinct identifiable stages prior to the onset of symptoms. Stage 1 is defined as the presence of β-cell autoimmunity as evidenced by the presence of two or more islet autoantibodies with normoglycemia and is presymptomatic, stage 2 as the presence of β-cell autoimmunity with dysglycemia and is presymptomatic, and stage 3 as onset of symptomatic disease. Adoption of this staging classification provides a standardized taxonomy for type 1 diabetes and will aid the development of therapies and the design of clinical trials to prevent symptomatic disease, promote precision medicine, and provide a framework for an optimized benefit/risk ratio that will impact regulatory approval, reimbursement, and adoption of interventions in the early stages of type 1 diabetes to prevent symptomatic disease.
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| 11. |
- Klepac, K., et al.
(författare)
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The G(q) signalling pathway inhibits brown and beige adipose tissue
- 2016
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Ingår i: Nature Communications. - : Springer Science and Business Media LLC. - 2041-1723. ; 7
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Tidskriftsartikel (refereegranskat)abstract
- Brown adipose tissue (BAT) dissipates nutritional energy as heat via the uncoupling protein-1 (UCP1) and BAT activity correlates with leanness in human adults. Here we profile G protein-coupled receptors (GPCRs) in brown adipocytes to identify druggable regulators of BAT. Twenty-one per cent of the GPCRs link to the G(q) family, and inhibition of G(q) signalling enhances differentiation of human and murine brown adipocytes. In contrast, activation of G(q) signalling abrogates brown adipogenesis. We further identify the endothelin/Ednra pathway as an autocrine activator of G(q) signalling in brown adipocytes. Expression of a constitutively active G(q) protein in mice reduces UCP1 expression in BAT, whole-body energy expenditure and the number of brown-like/beige cells in white adipose tissue (WAT). Furthermore, expression of G(q) in human WAT inversely correlates with UCP1 expression. Thus, our data indicate that G(q) signalling regulates brown/beige adipocytes and inhibition of G(q) signalling may be a novel therapeutic approach to combat obesity.
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| 12. |
- Lautner, Ronald, et al.
(författare)
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Preclinical effects of APOE epsilon 4 on cerebrospinal fluid A beta 42 concentrations
- 2017
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Ingår i: Alzheimers Research & Therapy. - : Springer Science and Business Media LLC. - 1758-9193. ; 9
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Tidskriftsartikel (refereegranskat)abstract
- Background: From earlier studies it is known that the APOE epsilon 2/epsilon 3/epsilon 4 polymorphism modulates the concentrations of cerebrospinal fluid (CSF) beta-amyloid(1-42) (A beta 42) in patients with cognitive decline due to Alzheimer's disease (AD), as well as in cognitively healthy controls. Here, in a large cohort consisting solely of cognitively healthy individuals, we aimed to evaluate how the effect of APOE on CSF A beta 42 varies by age, to understand the association between APOE and the onset of preclinical AD. Methods: APOE genotype and CSF A beta 42 concentration were determined in a cohort comprising 716 cognitively healthy individuals aged 17-99 from nine different clinical research centers. Results: CSF concentrations of A beta 42 were lower in APOE epsilon 4 carriers than in noncarriers in a gene dose-dependent manner. The effect of APOE epsilon 4 on CSF A beta 42 was age dependent. The age at which CSF A beta 42 concentrations started to decrease was estimated at 50 years in APOE epsilon 4-negative individuals and 43 years in heterozygous APOE epsilon 4 carriers. Homozygous APOE epsilon 4 carriers showed a steady decline in CSF A beta 42 concentrations with increasing age throughout the examined age span. Conclusions: People possessing the APOE epsilon 4 allele start to show a decrease in CSF A beta 42 concentration almost a decade before APOE epsilon 4 noncarriers already in early middle age. Homozygous APOE epsilon 4 carriers might deposit A beta 42 throughout the examined age span. These results suggest that there is an APOE epsilon 4-dependent period of early alterations in amyloid homeostasis, when amyloid slowly accumulates, that several years later, together with other downstream pathological events such as tau pathology, translates into cognitive decline.
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| 13. |
- Mackin, R. S., et al.
(författare)
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Cerebrospinal Fluid alpha-Synuclein and Lewy Body-Like Symptoms in Normal Controls, Mild Cognitive Impairment, and Alzheimer's Disease
- 2015
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Ingår i: Journal of Alzheimers Disease. - : IOS Press. - 1387-2877 .- 1875-8908. ; 43:3, s. 1007-1016
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Tidskriftsartikel (refereegranskat)abstract
- Background: Reduced cerebrospinal fluid (CSF) alpha-synuclein has been described in synucleinopathies, including dementia with Lewy bodies (DLB). Common symptoms of DLB include visual hallucinations and visuospatial and executive deficits. Co-occurrence of Lewy body pathology is common in Alzheimer's disease (AD) patients, but it is unknown if reduced CSF alpha-synuclein is associated with Lewy body-like symptomatology in AD. Objective: Determine associations between CSF alpha-synuclein and Lewy body-like symptomatology. Methods: We included 73 controls (NC), 121 mild cognitive impairment (MCI) patients, and 61 AD patients (median follow-up 3.5 years, range 0.6-7.8). We tested associations between baseline CSF alpha-synuclein and visual hallucinations and (longitudinal) cognition. Models were tested with and without co-varying for CSF total tau (T-tau), which is elevated in AD patients, and believed to reflect neurodegeneration. Results: Hallucinations were reported in 20% of AD patients, 13% of MCI patients, and 8% of NC. In AD, low CSF alpha-synuclein was associated with hallucinations. When adjusting for CSF T-tau, low CSF alpha-synuclein was associated with accelerated decline of executive function (NC, MCI, and AD), memory (MCI and AD), and language (MCI). Conclusion: The associations of low CSF alpha-synuclein with hallucinations and poor executive function, which are hallmarks of DLB, indirectly suggest that this biomarker may reflect underlying synuclein pathology. The associations with memory and language in MCI and AD suggests either that reduced CSF alpha-synuclein also partly reflects global impaired neuronal/synaptic function, or that non-specific overall cognitive deterioration is accelerated in the presence of synuclein related pathology. The findings will require autopsy verification.
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| 14. |
- Mattsson, Niklas, 1979, et al.
(författare)
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Association of brain amyloid-beta with cerebral perfusion and structure in Alzheimer's disease and mild cognitive impairment
- 2014
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Ingår i: Brain. - : Oxford University Press (OUP). - 0006-8950 .- 1460-2156. ; 137, s. 1550-1561
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Tidskriftsartikel (refereegranskat)abstract
- Patients with Alzheimer's disease have reduced cerebral blood flow measured by arterial spin labelling magnetic resonance imaging, but it is unclear how this is related to amyloid-beta pathology. Using 182 subjects from the Alzheimer's Disease Neuroimaging Initiative we tested associations of amyloid-beta with regional cerebral blood flow in healthy controls (n = 51), early (n = 66) and late (n = 41) mild cognitive impairment, and Alzheimer's disease with dementia (n = 24). Based on the theory that Alzheimer's disease starts with amyloid-beta accumulation and progresses with symptoms and secondary pathologies in different trajectories, we tested if cerebral blood flow differed between amyloid-beta-negative controls and -positive subjects in different diagnostic groups, and if amyloid-beta had different associations with cerebral blood flow and grey matter volume. Global amyloid-beta load was measured by florbetapir positron emission tomography, and regional blood flow and volume were measured in eight a priori defined regions of interest. Cerebral blood flow was reduced in patients with dementia in most brain regions. Higher amyloid-beta load was related to lower cerebral blood flow in several regions, independent of diagnostic group. When comparing amyloid-beta-positive subjects with -negative controls, we found reductions of cerebral blood flow in several diagnostic groups, including in precuneus, entorhinal cortex and hippocampus (dementia), inferior parietal cortex (late mild cognitive impairment and dementia), and inferior temporal cortex (early and late mild cognitive impairment and dementia). The associations of amyloid-beta with cerebral blood flow and volume differed across the disease spectrum, with high amyloid-beta being associated with greater cerebral blood flow reduction in controls and greater volume reduction in late mild cognitive impairment and dementia. In addition to disease stage, amyloid-beta pathology affects cerebral blood flow across the span from controls to dementia patients. Amyloid-beta pathology has different associations with cerebral blood flow and volume, and may cause more loss of blood flow in early stages, whereas volume loss dominates in late disease stages.
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| 15. |
- Mattsson, Niklas, 1979, et al.
(författare)
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CSF protein biomarkers predicting longitudinal reduction of CSF β-amyloid42 in cognitively healthy elders
- 2013
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Ingår i: Translational Psychiatry. - : Springer Science and Business Media LLC. - 2158-3188 .- 2158-3188. ; 3
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Tidskriftsartikel (refereegranskat)abstract
- β-amyloid (Ab) plaque accumulation is a hallmark of Alzheimer's disease (AD). It is believed to start many years prior to symptoms and is reflected by reduced cerebrospinal fluid (CSF) levels of the peptide Aβ1-42 (Aβ42). Here we tested the hypothesis that baseline levels of CSF proteins involved in microglia activity, synaptic function and Ab metabolism predict the development of Ab plaques, assessed by longitudinal CSF Aβ42 decrease in cognitively healthy people. Forty-six healthy people with three to four serial CSF samples were included (mean follow-up 3 years, range 2-4 years). There was an overall reduction in Aβ42 from a mean concentration of 211-195 pg ml1 after 4 years. Linear mixed-effects models using longitudinal Aβ42 as the response variable, and baseline proteins as explanatory variables (n=69 proteins potentially relevant for Ab metabolism, microglia or synaptic/neuronal function), identified 10 proteins with significant effects on longitudinal Aβ42. The most significant proteins were angiotensinconverting enzyme (ACE, P=0.009), Chromogranin A (CgA, P=0.009) and Axl receptor tyrosine kinase (AXL, P=0.009). Receiveroperating characteristic analysis identified 11 proteins with significant effects on longitudinal Aβ42 (largely overlapping with the proteins identified by linear mixed-effects models). Several proteins (including ACE, CgA and AXL) were associated with Aβ42 reduction only in subjects with normal baseline Aβ42, and not in subjects with reduced baseline Aβ42. We conclude that baseline CSF proteins related to Ab metabolism, microglia activity or synapses predict longitudinal Aβ42 reduction in cognitively healthy elders. The finding that some proteins only predict Aβ42 reduction in subjects with normal baseline Aβ42 suggest that they predict future development of the brain Ab pathology at the earliest stages of AD, prior to widespread development of Aβ plaques. © 2013 Macmillan Publishers Limited All rights reserved.
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| 16. |
- Mattsson, Niklas, 1979, et al.
(författare)
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Effects of Baseline CSF alpha-Synuclein on Regional Brain Atrophy Rates in Healthy Elders, Mild Cognitive Impairment and Alzheimer's Disease
- 2013
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Ingår i: Plos One. - : Public Library of Science (PLoS). - 1932-6203. ; 8:12
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Tidskriftsartikel (refereegranskat)abstract
- Background: Cerebrospinal fluid (CSF) alpha-synuclein is reduced in synucleinopathies, including dementia with Lewy bodies, and some studies have found increased CSF alpha-synuclein in Alzheimer's disease (AD). No study has explored effects of CSF alpha-synuclein on brain atrophy. Here we tested if baseline CSF alpha-synuclein affects brain atrophy rates and if these effects vary across brain regions, and across the cognitive spectrum from healthy elders (NL), to patients with mild cognitive impairment (MCI) and AD. Methods: Baseline CSF alpha-synuclein measurements and longitudinal structural brain magnetic resonance imaging was performed in 74 NL, 118 MCI patients and 55 AD patients. Effects of baseline CSF alpha-synuclein on regional atrophy rates were tested in 1) four pre-hoc defined regions possibly associated with Lewy body and/or AD pathology (amygdala, caudate, hippocampus, brainstem), and 2) all available regions of interest. Differences across diagnoses were tested by assessing the interaction of CSF alpha-synuclein and diagnosis (testing NL versus MCI, and NL versus AD). Results: The effects of CSF alpha-synuclein on longitudinal atrophy rates were not significant after correction for multiple comparisons. There were tendencies for effects in AD in caudate (higher atrophy rates in subjects with higher CSF alpha-synuclein, P=0.046) and brainstem (higher atrophy rates in subjects with lower CSF alpha-synuclein, P=0.063). CSF alpha-synuclein had significantly different effects on atrophy rates in NL and AD in brainstem (P=0.037) and caudate (P=0.006). Discussion: With the possible exception of caudate and brainstem, the overall weak effects of CSF alpha-synuclein on atrophy rates in NL, MCI and AD argues against CSF alpha-synuclein as a biomarker related to longitudinal brain atrophy in these diagnostic groups. Any effects of CSF alpha-synuclein may be attenuated by possible simultaneous occurrence of AD-related neuronal injury and concomitant Lewy body pathology, which may elevate and reduce CSF alpha-synuclein levels, respectively.
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| 17. |
- Mattsson, Niklas, 1979, et al.
(författare)
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Effects of cerebrospinal fluid proteins on brain atrophy rates in cognitively healthy older adults
- 2014
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Ingår i: Neurobiology of Aging. - : Elsevier BV. - 0197-4580. ; 35:3, s. 614-622
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Tidskriftsartikel (refereegranskat)abstract
- Biomarkers associated with Alzheimer's disease (AD)-like brain atrophy in healthy individuals may identify mechanisms involved in early stage AD. Aside from cerebrospinal fluid (CSF) beta-amyloid42 (A beta 42) and tau, no studies have tested associations between CSF proteins and AD-like brain atrophy. We studied 90 healthy elders, who underwent lumbar puncture at baseline, and serial magnetic resonance imaging scans for up to 4 years. We tested statistical effects of baseline CSF proteins (N = 70 proteins related to A beta 42-metabolism, microglial activity, and synaptic/neuronal function) on atrophy rates in 7 AD-related regions. Besides the effects of A beta 42 and phosphorylated tau (P-tau) that were seen in several regions, novel CSF proteins were found to have effects in inferior and middle temporal cortex (including apolipoprotein CIII, apolipoprotein D, and apolipoprotein H). Several proteins (including S100 beta and matrix metalloproteinase-3) had effects that depended on the presence of brain A beta pathology, as measured by CSF A beta 42. Other proteins (including P-tau and apolipoprotein D) had effects even after adjusting for CSF A beta 42. The statistical effects in this exploratory study were mild and not significant after correction for multiple comparisons, but some of the identified proteins may be associated with brain atrophy in healthy persons. Proteins interacting with CSF A beta 42 may be related to A beta brain pathology, whereas proteins associated with atrophy even after adjusting for CSF A beta 42 may be related to A beta-independent mechanisms. (C) 2014 Elsevier Inc. All rights reserved.
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| 18. |
- Mattsson, Niklas, 1979, et al.
(författare)
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Emerging β-amyloid pathology and accelerated cortical atrophy
- 2014
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Ingår i: JAMA Neurology. - : American Medical Association (AMA). - 2168-6149. ; 71:6, s. 725-734
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Tidskriftsartikel (refereegranskat)abstract
- IMPORTANCE The effect of β-amyloid (Aβ) accumulation on regional structural brain changes in early stages of Alzheimer disease (AD) is not well understood. OBJECTIVE To test the hypothesis that the development of Aβ pathology is related to increased regional atrophy in the brains of cognitively normal (CN) persons. DESIGN, SETTING, AND PARTICIPANTS Longitudinal clinicobiomarker cohort study involving 47 CN control subjects and 15 patients with AD dementia. All participants underwent repeated cerebrospinal fluid Aβ42 and structural magnetic resonance imaging measurements for up to 4 years. Cognitively normal controls were classified using the longitudinal cerebrospinal fluid Aβ42 data and included 13 stable Aβ negative (normal baseline Aβ42 levels, with less than the median reduction over time), 13 declining Aβ negative (normal baseline Aβ42 levels, with greater than the median reduction over time), and 21 Aβ positive (pathologic baseline Aβ42 levels). All 15 patients with AD dementia were Aβ positive. MAIN OUTCOMES AND MEASURES Group effects on regional gray matter volumes at baseline and over time, tested by linear mixed-effects models. RESULTS Baseline gray matter volumes were similar among the CN Aβ groups, but atrophy rates were increased in frontoparietal regions in the declining Aβ-negative and Aβ-positive groups and in amygdala and temporal regions in the Aβ-positive group. Aβ-positive patients with AD dementia had further increased atrophy rates in hippocampus and temporal and cingulate regions. CONCLUSIONS AND RELEVANCE Emerging Aβ pathology is coupled to increased frontoparietal (but not temporal) atrophy rates. Atrophy rates peak early in frontoparietal regions but accelerate in hippocampus, temporal, and cingulate regions as the disease progresses to dementia. Early-stage Aβ pathologymay have mild effects on local frontoparietal cortical integrity while effects in temporal regions appear later and accelerate, leading to the atrophy pattern typically seen in AD. © 2014 American Medical Association.
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| 19. |
- Molina, DM, et al.
(författare)
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The Cellular Thermal Shift Assay: A Novel Biophysical Assay for In Situ Drug Target Engagement and Mechanistic Biomarker Studies
- 2016
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Ingår i: Annual review of pharmacology and toxicology. - : Annual Reviews. - 1545-4304 .- 0362-1642. ; 56, s. 141-161
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Tidskriftsartikel (refereegranskat)abstract
- A drug must engage its intended target to achieve its therapeutic effect. However, conclusively measuring target engagement (TE) in situ is challenging. This complicates preclinical development and is considered a key factor in the high rate of attrition in clinical trials. Here, we discuss a recently developed, label-free, biophysical assay, the cellular thermal shift assay (CETSA), which facilitates the direct assessment of TE in cells and tissues at various stages of drug development. CETSA also reveals biochemical events downstream of drug binding and therefore provides a promising means of establishing mechanistic biomarkers. The implementation of proteome-wide CETSA using quantitative mass spectrometry represents a novel strategy for defining off-target toxicity and polypharmacology and for identifying downstream mechanistic biomarkers. The first year of CETSA applications in the literature has focused on TE studies in cell culture systems and has confirmed the broad applicability of CETSA to many different target families. The next phase of CETSA applications will likely encompass comprehensive animal and patient studies, and CETSA will likely serve as a very valuable tool in many stages of preclinical and clinical drug development.
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| 20. |
- Moseby-Knappe, Marion, et al.
(författare)
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Serum Neurofilament Light Chain for Prognosis of Outcome after Cardiac Arrest
- 2019
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Ingår i: JAMA Neurology. - : American Medical Association (AMA). - 2168-6149 .- 2168-6157. ; 76:1, s. 64-64
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Tidskriftsartikel (refereegranskat)abstract
- Importance: Prognostication of neurologic outcome after cardiac arrest is an important but challenging aspect of patient therapy management in critical care units. Objective: To determine whether serum neurofilament light chain (NFL) levels can be used for prognostication of neurologic outcome after cardiac arrest. Design, Setting and Participants: Prospective clinical biobank study of data from the randomized Target Temperature Management After Cardiac Arrest trial, an international, multicenter study with 29 participating sites. Patients were included between November 11, 2010, and January 10, 2013. Serum NFL levels were analyzed between August 1 and August 23, 2017, after trial completion. A total of 782 unconscious patients with out-of-hospital cardiac arrest of presumed cardiac origin were eligible. Exposures: Serum NFL concentrations analyzed at 24, 48, and 72 hours after cardiac arrest with an ultrasensitive immunoassay. Main Outcomes and Measures: Poor neurologic outcome at 6-month follow-up, defined according to the Cerebral Performance Category Scale as cerebral performance category 3 (severe cerebral disability), 4 (coma), or 5 (brain death). Results: Of 782 eligible patients, 65 patients (8.3%) were excluded because of issues with aliquoting, missing sampling, missing outcome, or transport problems of samples. Of the 717 patients included (91.7%), 580 were men (80.9%) and median (interquartile range [IQR]) age was 65 (56-73) years. A total of 360 patients (50.2%) had poor neurologic outcome at 6 months. Median (IQR) serum NFL level was significantly increased in the patients with poor outcome vs good outcome at 24 hours (1426 [299-3577] vs 37 [20-70] pg/mL), 48 hours (3240 [623-8271] vs 46 [26-101] pg/mL), and 72 hours (3344 [845-7838] vs 54 [30-122] pg/mL) (P <.001 at all time points), with high overall performance (area under the curve, 0.94-0.95) and high sensitivities at high specificities (eg, 69% sensitivity with 98% specificity at 24 hours). Serum NFL levels had significantly greater performance than the other biochemical serum markers (ie, tau, neuron-specific enolase, and S100). At comparable specificities, serum NFL levels had greater sensitivity for poor outcome compared with routine electroencephalogram, somatosensory-evoked potentials, head computed tomography, and both pupillary and corneal reflexes (ranging from 29.2% to 49.0% greater for serum NFL level). Conclusions and Relevance: Findings from this study suggest that the serum NFL level is a highly predictive marker of long-term poor neurologic outcome at 24 hours after cardiac arrest and may be a useful complement to currently available neurologic prognostication methods.
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