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- Ismail, MA, et al.
(författare)
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27-Hydroxycholesterol impairs neuronal glucose uptake through an IRAP/GLUT4 system dysregulation
- 2017
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Ingår i: The Journal of experimental medicine. - : Rockefeller University Press. - 1540-9538 .- 0022-1007. ; 214:3, s. 699-717
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Tidskriftsartikel (refereegranskat)abstract
- Hypercholesterolemia is associated with cognitively deteriorated states. Here, we show that excess 27-hydroxycholesterol (27-OH), a cholesterol metabolite passing from the circulation into the brain, reduced in vivo brain glucose uptake, GLUT4 expression, and spatial memory. Furthermore, patients exhibiting higher 27-OH levels had reduced 18F-fluorodeoxyglucose uptake. This interplay between 27-OH and glucose uptake revealed the engagement of the insulin-regulated aminopeptidase (IRAP). 27-OH increased the levels and activity of IRAP, countered the IRAP antagonist angiotensin IV (AngIV)–mediated glucose uptake, and enhanced the levels of the AngIV-degrading enzyme aminopeptidase N (AP-N). These effects were mediated by liver X receptors. Our results reveal a molecular link between cholesterol, brain glucose, and the brain renin-angiotensin system, all of which are affected in some neurodegenerative diseases. Thus, reducing 27-OH levels or inhibiting AP-N maybe a useful strategy in the prevention of the altered glucose metabolism and memory decline in these disorders.
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- Papathoma, PE, et al.
(författare)
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A replication study, systematic review and meta-analysis of automated image-based diagnosis in parkinsonism
- 2022
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Ingår i: Scientific reports. - : Springer Science and Business Media LLC. - 2045-2322. ; 12:1, s. 2763-
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Tidskriftsartikel (refereegranskat)abstract
- Differential diagnosis of parkinsonism early upon symptom onset is often challenging for clinicians and stressful for patients. Several neuroimaging methods have been previously evaluated; however specific routines remain to be established. The aim of this study was to systematically assess the diagnostic accuracy of a previously developed 18F-fluorodeoxyglucose positron emission tomography (FDG-PET) based automated algorithm in the diagnosis of parkinsonian syndromes, including unpublished data from a prospective cohort. A series of 35 patients prospectively recruited in a movement disorder clinic in Stockholm were assessed, followed by systematic literature review and meta-analysis. In our cohort, automated image-based classification method showed excellent sensitivity and specificity for Parkinson Disease (PD) vs. atypical parkinsonian syndromes (APS), in line with the results of the meta-analysis (pooled sensitivity and specificity 0.84; 95% CI 0.79–0.88 and 0.96; 95% CI 0.91 –0.98, respectively). In conclusion, FDG-PET automated analysis has an excellent potential to distinguish between PD and APS early in the disease course and may be a valuable tool in clinical routine as well as in research applications.
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- Berntsson, Shala, et al.
(författare)
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11c-methionine PET combined with advanced MRI for the preoperative evaluation of suspected diffuse low-grade gliomas
- 2012
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Ingår i: Neuro-Oncology. - : Oxford University Press (OUP). - 1522-8517 .- 1523-5866. ; 14:suppl 3, s. iii11-iii12
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- PURPOSE: To evaluate positron emission tomography (PET) with the tracer 11C-methionine (MET) combined with perfusion- and diffusion MRI (pMRI and dMRI) for the preoperative evaluation of patients with suspected diffuse low-grade gliomas (DLGG).MATERIALS AND METHODS: In this prospective study with institutional review board approval, 25 patients with suspected DLGG in cortical structures (n=24) were examined with 11C-methionine PET (MET PET), pMRI and dMRI. The hot spot (HS) in the tumor, i.e. the area with highest MET uptake, was used as a reference region for evaluating maximum relative cerebral blood volume (rCBVmax) and minimum apparent diffusion coefficient values (ADCmin) by MRI. The concordance between MET PET, pMRI and dMRI, as single parameters and combined, was assessed with respect to histological tumor diagnosis, which was available for 18 patients.RESULTS: In all but one patient tumor diagnosis was confirmed. The region showing highest rCBVmax corresponded with the HS region identified by MET PET in all cases, and a positive correlation between MET uptake and rCBVmax was found (Spearman: r=0.67, P < 0.0001). The concordance between MET uptake and rCBVmax in predicting malignancy grade of gliomas was 67%. MET uptake in the HS was inversely correlated with ADCmin values measured in this region (Spearman: r=-0.54, p < 0.005).CONCLUSION: MET PET combined with advanced MRI facilitates the identification of specific regions of interest for histological tumor diagnosis and thereby provides a powerful tool in the preoperative evaluation of DLGG.
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- Bucci, M., et al.
(författare)
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Profiling of plasma biomarkers in the context of memory assessment in a tertiary memory clinic
- 2023
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Ingår i: Translational Psychiatry. - 2158-3188. ; 13:1
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Tidskriftsartikel (refereegranskat)abstract
- Plasma biomarkers have shown promising performance in research cohorts in discriminating between different stages of Alzheimer's disease (AD). Studies in clinical populations are necessary to provide insights on the clinical utility of plasma biomarkers before their implementation in real-world settings. Here we investigated plasma biomarkers (glial fibrillary acidic protein (GFAP), tau phosphorylated at 181 and 231 (pTau181, pTau231), amyloid & beta; (A & beta;) 42/40 ratio, neurofilament light) in 126 patients (age = 65 & PLUSMN; 8) who were admitted to the Clinic for Cognitive Disorders, at Karolinska University Hospital. After extensive clinical assessment (including CSF analysis), patients were classified as: mild cognitive impairment (MCI) (n = 75), AD (n = 25), non-AD dementia (n = 16), no dementia (n = 9). To refine the diagnosis, patients were examined with [F-18]flutemetamol PET (A & beta;-PET). A & beta;-PET images were visually rated for positivity/negativity and quantified in Centiloid. Accordingly, 68 A & beta;+ and 54 A & beta;- patients were identified. Plasma biomarkers were measured using single molecule arrays (SIMOA). Receiver-operated curve (ROC) analyses were performed to detect A & beta;-PET+ using the different biomarkers. In the whole cohort, the A & beta;-PET centiloid values correlated positively with plasma GFAP, pTau231, pTau181, and negatively with A & beta;42/40 ratio. While in the whole MCI group, only GFAP was associated with A & beta; PET centiloid. In ROC analyses, among the standalone biomarkers, GFAP showed the highest area under the curve discriminating A & beta;+ and A & beta;- compared to other plasma biomarkers. The combination of plasma biomarkers via regression was the most predictive of A & beta;-PET, especially in the MCI group (prior to PET, n = 75) (sensitivity = 100%, specificity = 82%, negative predictive value = 100%). In our cohort of memory clinic patients (mainly MCI), the combination of plasma biomarkers was sensitive in ruling out A & beta;-PET negative individuals, thus suggesting a potential role as rule-out tool in clinical practice.
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- Chiotis, K., et al.
(författare)
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Longitudinal changes of tau PET imaging in relation to hypometabolism in prodromal and Alzheimer's disease dementia
- 2018
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Ingår i: Molecular Psychiatry. - : Springer Science and Business Media LLC. - 1359-4184 .- 1476-5578. ; 23:7, s. 1666-1673
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Tidskriftsartikel (refereegranskat)abstract
- The development of tau-specific positron emission tomography (PET) tracers allows imaging in vivo the regional load of tau pathology in Alzheimer's disease (AD) and other tauopathies. Eighteen patients with baseline investigations enroled in a 17-month follow-up study, including 16 with AD (10 had mild cognitive impairment and a positive amyloid PET scan, that is, prodromal AD, and six had AD dementia) and two with corticobasal syndrome. All patients underwent PET scans with [F-18]THK5317 (tau deposition) and [F-18]FDG (glucose metabolism) at baseline and follow-up, neuropsychological assessment at baseline and follow-up and a scan with [C-11]PIB (amyloid-beta deposition) at baseline only. At a group level, patients with AD (prodromal or dementia) showed unchanged [F-18]THK5317 retention over time, in contrast to significant decreases in [F-18]FDG uptake in temporoparietal areas. The pattern of changes in [F-18]THK5317 retention was heterogeneous across all patients, with qualitative differences both between the two AD groups (prodromal and dementia) and among individual patients. High [F-18]THK5317 retention was significantly associated over time with low episodic memory encoding scores, while low [F-18]FDG uptake was significantly associated over time with both low global cognition and episodic memory encoding scores. Both patients with corticobasal syndrome had a negative [C-11]PIB scan, high [F-18]THK5317 retention with a different regional distribution from that in AD, and a homogeneous pattern of increased [F-18]THK5317 retention in the basal ganglia over time. These findings highlight the heterogeneous propagation of tau pathology among patients with symptomatic AD, in contrast to the homogeneous changes seen in glucose metabolism, which better tracked clinical progression.
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