| 1. |
- Alawode, Deborah O T, et al.
(författare)
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Transitioning from cerebrospinal fluid to blood tests to facilitate diagnosis and disease monitoring in Alzheimer's disease.
- 2021
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Ingår i: Journal of internal medicine. - : Wiley. - 1365-2796 .- 0954-6820. ; 290:3, s. 583-601
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Tidskriftsartikel (refereegranskat)abstract
- Alzheimer's disease (AD) is increasingly prevalent worldwide, and disease-modifying treatments may soon be at hand; hence now, more than ever, there is a need to develop techniques that allow earlier and more secure diagnosis. Current biomarker-based guidelines for AD diagnosis, which have replaced the historical symptom-based guidelines, rely heavily on neuroimaging and cerebrospinal fluid (CSF) sampling. Whilst these have greatly improved the diagnostic accuracy of AD pathophysiology, they are less practical for application in primary care, population-based and epidemiological settings, or where resources are limited. In contrast, blood is a more accessible and cost-effective source of biomarkers in AD. In this review paper, using the recently proposed amyloid, tau and neurodegeneration [AT(N)] criteria as a framework towards a biological definition of AD, we discuss recent advances in biofluid-based biomarkers, with a particular emphasis on those with potential to be translated into blood-based biomarkers. We provide an overview of the research conducted both in CSF and in blood to draw conclusions on biomarkers that show promise. Given the evidence collated in this review, plasma neurofilament light chain (N), and phosphorylated tau (p-tau; T) show particular potential for translation into clinical practice. However, p-tau requires more comparisons to be conducted between its various epitopes before conclusions can be made as to which one most robustly differentiates AD from non-AD dementias. Plasma amyloid beta (A) would prove invaluable as an early screening modality, but it requires very precise tests and robust pre-analytical protocols.
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| 2. |
- Ashton, Nicholas J., et al.
(författare)
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Effects of pre-analytical procedures on blood biomarkers for Alzheimer's pathophysiology, glial activation, and neurodegeneration.
- 2021
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Ingår i: Alzheimer's & dementia (Amsterdam, Netherlands). - : Wiley. - 2352-8729. ; 13:1
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Tidskriftsartikel (refereegranskat)abstract
- We tested how tube types (ethylenediaminetetraacetic acid [EDTA], serum, lithium heparin [LiHep], and citrate) and freeze-thaw cycles affect levels of blood biomarkers for Alzheimer's disease (AD) pathophysiology, glial activation, and neuronal injury.Amyloid beta (Aβ)42, Aβ40, phosphorylated tau181 (p-tau181), glial fibrillary acidic protein, total tau (t-tau), neurofilament light, and phosphorylated neurofilament heavy protein were measured using single molecule arrays.LiHep demonstrated the highest mean value for all biomarkers. Tube types were highly correlated for most biomarkers (r > 0.95) but gave significantly different absolute concentrations. Weaker correlations between tube types were found for Aβ42/40 (r = 0.63-0.86) and serum t-tau (r = 0.46-0.64). Freeze-thaw cycles highly influenced levels of serum Aβ and t-tau (P < .0001), and minor decreases in EDTA Aβ40 and EDTA p-tau181 were found after freeze-thaw cycle 4 (P < .05).The same tube type should be used in research studies on blood biomarkers. Individual concentration cut-offs are needed for each tube type in all tested biomarkers despite being highly correlated. Serum should be avoided for Aβ42, Aβ40, and t-tau. Freeze-thaw cycles > 3 should be avoided for p-tau181.
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| 3. |
- Benussi, Alberto, et al.
(författare)
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Diagnostic and prognostic value of serum NfL and p-Tau181 in frontotemporal lobar degeneration.
- 2020
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Ingår i: Journal of neurology, neurosurgery, and psychiatry. - : BMJ. - 1468-330X .- 0022-3050. ; 91:9, s. 960-967
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Tidskriftsartikel (refereegranskat)abstract
- To assess the diagnostic and prognostic value of serum neurofilament light (NfL) and serum phospho-Tau181 (p-Tau181) in a large cohort of patients with frontotemporal lobar degeneration (FTLD).In this retrospective study, performed on 417 participants, we analysed serum NfL and p-Tau181 concentrations with an ultrasensitive single molecule array (Simoa) approach. We assessed the diagnostic values of serum biomarkers in the differential diagnosis between FTLD, Alzheimer's disease (AD) and healthy ageing; their role as markers of disease severity assessing the correlation with clinical variables, cross-sectional brain imaging and neurophysiological data; their role as prognostic markers, considering their ability to predict survival probability in FTLD.We observed significantly higher levels of serum NfL in patients with FTLD syndromes, compared with healthy controls, and lower levels of p-Tau181 compared with patients with AD. Serum NfL concentrations showed a high accuracy in discriminating between FTLD and healthy controls (area under the curve (AUC): 0.86, p<0.001), while serum p-Tau181 showed high accuracy in differentiating FTLD from patients with AD (AUC: 0.93, p<0.001). In FTLD, serum NfL levels correlated with measures of cognitive function, disease severity and behavioural disturbances and were associated with frontotemporal atrophy and indirect measures of GABAergic deficit. Moreover, serum NfL concentrations were identified as the best predictors of survival probability.The assessment of serum NfL and p-Tau181 may provide a comprehensive view of FTLD, aiding in the differential diagnosis, in staging disease severity and in defining survival probability.
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| 4. |
- Brum, Wagner S., et al.
(författare)
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Biological variation estimates of Alzheimer's disease plasma biomarkers in healthy individuals
- 2024
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Ingår i: Alzheimer's and Dementia. - 1552-5260 .- 1552-5279. ; 20:2, s. 1284-1297
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Tidskriftsartikel (refereegranskat)abstract
- INTRODUCTION: Blood biomarkers have proven useful in Alzheimer's disease (AD) research. However, little is known about their biological variation (BV), which improves the interpretation of individual-level data. METHODS: We measured plasma amyloid beta (Aβ42, Aβ40), phosphorylated tau (p-tau181, p-tau217, p-tau231), glial fibrillary acidic protein (GFAP), and neurofilament light chain (NfL) in plasma samples collected weekly over 10 weeks from 20 participants aged 40 to 60 years from the European Biological Variation Study. We estimated within- (CVI) and between-subject (CVG) BV, analytical variation, and reference change values (RCV). RESULTS: Biomarkers presented considerable variability in CVI and CVG. Aβ42/Aβ40 had the lowest CVI (≈ 3%) and p-tau181 the highest (≈ 16%), while others ranged from 6% to 10%. Most RCVs ranged from 20% to 30% (decrease) and 25% to 40% (increase). DISCUSSION: BV estimates for AD plasma biomarkers can potentially refine their clinical and research interpretation. RCVs might be useful for detecting significant changes between serial measurements when monitoring early disease progression or interventions. Highlights Plasma amyloid beta (Aβ42/Aβ40) presents the lowest between- and within-subject biological variation, but also changes the least in Alzheimer's disease (AD) patients versus controls. Plasma phosphorylated tau variants significantly vary in their within-subject biological variation, but their substantial fold-changes in AD likely limits the impact of their variability. Plasma neurofilament light chain and glial fibrillary acidic protein demonstrate high between-subject variation, the impact of which will depend on clinical context. Reference change values can potentially be useful in monitoring early disease progression and the safety/efficacy of interventions on an individual level. Serial sampling revealed that unexpectedly high values in heathy individuals can be observed, which urges caution when interpreting AD plasma biomarkers based on a single test result.
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| 5. |
- Chatterjee, Pratishtha, et al.
(författare)
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Diagnostic and prognostic plasma biomarkers for preclinical Alzheimer's disease.
- 2022
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Ingår i: Alzheimer's & dementia : the journal of the Alzheimer's Association. - : Wiley. - 1552-5279. ; 18:6, s. 1141-1154
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Tidskriftsartikel (refereegranskat)abstract
- This study involved a parallel comparison of the diagnostic and longitudinal monitoring potential of plasma glial fibrillary acidic protein (GFAP), total tau (t-tau), phosphorylated tau (p-tau181 and p-tau231), and neurofilament light (NFL) in preclinical Alzheimer's disease (AD).Plasma proteins were measured using Simoa assays in cognitively unimpaired older adults (CU), with either absence (Aβ-) or presence (Aβ+) of brain amyloidosis.Plasma GFAP, t-tau, p-tau181, and p-tau231 concentrations were higher in Aβ+ CU compared with Aβ- CU cross-sectionally. GFAP had the highest effect size and area under the curve (AUC) in differentiating between Aβ+ and Aβ- CU; however, no statistically significant differences were observed between the AUCs of GFAP, p-tau181, and p-tau231, but all were significantly higher than the AUC of NFL, and the AUC of GFAP was higher than the AUC of t-tau. The combination of a base model (BM), comprising the AD risk factors, age, sex, and apolipoprotein E gene (APOE) ε4 status with GFAP was observed to have a higher AUC (>90%) compared with the combination of BM with any of the other proteins investigated in the current study. Longitudinal analyses showed increased GFAP and p-tau181 in Aβ+ CU and increased NFL in Aβ- CU, over a 12-month duration. GFAP, p-tau181, p-tau231, and NFL showed significant correlations with cognition, whereas no significant correlations were observed with hippocampal volume.These findings highlight the diagnostic and longitudinal monitoring potential of GFAP and p-tau for preclinical AD.
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| 6. |
- Correia, M., et al.
(författare)
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Early plasma biomarker dynamic profiles are associated with acute ischemic stroke outcomes
- 2022
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Ingår i: European Journal of Neurology. - : Wiley. - 1351-5101 .- 1468-1331. ; 29:6, s. 1630-1642
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Tidskriftsartikel (refereegranskat)abstract
- Background Early outcome prediction after acute ischemic stroke (AIS) might be improved with blood-based biomarkers. We investigated whether the longitudinal profile of a multi-marker panel could predict the outcome of successfully recanalized AIS patients. Methods We used ultrasensitive single-molecule array (Simoa) to measure glial fibrillary acidic protein (GFAP), neurofilament light chain (NfL), total-tau (t-tau) and ELISA for brevican in a prospective study of AIS patients with anterior circulation large vessel occlusion successfully submitted to thrombectomy. Plasma was obtained at admission, upon treatment, 24 h and 72 h after treatment. Clinical and neuroimaging outcomes were assessed independently. Results Thirty-five patients (64.8%) had good early clinical or neuroimaging outcome. Baseline biomarker levels did not distinguish between outcomes. However, longitudinal intra-individual biomarker changes followed different dynamic profiles with time and according to outcome. GFAP levels exhibited an early and prominent increase between admission and just after treatment. NfL increase was less pronounced between admission and up to 24 h. T-tau increased between treatment and 24 h. Interestingly, GFAP rate-of-change (pg/ml/h) between admission and immediately after recanalization had a good discriminative capacity between clinical outcomes (AUC = 0.88, p < 0.001), which was higher than admission CT-ASPECTS (AUC = 0.75, p < 0.01). T-tau rate-of-change provided moderate discriminative capacity (AUC = 0.71, p < 0.05). Moreover, in AIS patients with admission CT-ASPECTS <9 both GFAP and NfL rate-of-change were good outcome predictors (AUC = 0.82 and 0.77, p < 0.05). Conclusion Early GFAP, t-tau and NfL rate-of-change in plasma can predict AIS clinical and neuroimaging outcome after successful recanalization. Such dynamic measures match and anticipate neuroimaging predictive capacity, potentially improving AIS patient stratification for treatment, and targeting individualized stroke care.
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| 7. |
- Dittrich, Anna, 1972, et al.
(författare)
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Association of Chronic Kidney Disease With Plasma NfL and Other Biomarkers of Neurodegeneration: The H70 Birth Cohort Study in Gothenburg.
- 2023
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Ingår i: Neurology. - 1526-632X. ; 101:3, s. e277-e288
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Tidskriftsartikel (refereegranskat)abstract
- Studies associate chronic kidney disease (CKD) with neurodegeneration. This study investigated the relationship between kidney function, blood, CSF, and structural brain MRI markers of neurodegeneration in a sample including individuals with and without CKD.Participants from the Gothenburg H70 Birth Cohort Study, with data on plasma neurofilament light (P-NfL), estimated glomerular filtration rate (eGFR), and structural brain MRI were included. Participants were invited to also have the CSF collected. The primary endpoint of this study was to determine any association between CKD and P-NfL. Secondary endpoints included cross-sectional associations between CKD, eGFR, and CSF-derived and MRI-derived markers of neurodegeneration and Alzheimer disease (AD) pathology (MRI: cortical thickness, hippocampal volume, lateral ventricle volume, and white matter lesion volume; CSF: β-amyloid (Aβ) 42, Aβ42/40, Aβ42/p-tau, t-tau, p-tau, and NfL). Participants with P-NfL and eGFR at baseline were re-examined on eGFR, 5.5 (5.3-6.1) years (median; IQR) after the first visit, and the predictive value of P-NfL levels on incident CKD was estimated longitudinally, using a Cox proportional hazards model.We included 744 participants, 668 without CKD (age 71 [70-71] years, 50% males) and 76 with CKD (age 71 [70-71] years, 39% males). Biomarkers from the CSF were analyzed in 313 participants. A total of 558 individuals returned for a re-examination of eGFR (75% response rate, age 76 [76; 77] years, 48% males, 76 new cases of CKD). Participants with CKD had higher P-NfL levels than those with normal kidney function (median; 18.8 vs 14.1 pg/mL, p < 0.001), while MRI and CSF markers were similar between the groups. P-NfL was independently associated with CKD after adjustment for confounding variables, including hypertension and diabetes (OR; 3.231, p < 0.001), in a logistic regression model. eGFR and CSF Aβ 42/40: R = 0.23, p = 0.004 correlated in participants with Aβ42 pathology. P-NfL levels in the highest quartile were associated with incident CKD at follow-up (HR; 2.39 [1.21: 4.72]).In a community-based cohort of 70-year olds, P-NfL was associated with both prevalent and incident CKD, while CSF and/or imaging measures did not differ by CKD status. Participants with CKD and dementia presented similar levels of P-NfL.
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| 8. |
- Dittrich, Anna, 1972, et al.
(författare)
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Plasma and CSF NfL are differentially associated with biomarker evidence of neurodegeneration in a community-based sample of 70-year-olds
- 2022
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Ingår i: Alzheimer's & Dementia: Diagnosis, Assessment & Disease Monitoring. - : Wiley. - 2352-8729. ; 14:1
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Tidskriftsartikel (refereegranskat)abstract
- Neurofilament light protein (NfL) in cerebrospinal fluid (CSF) and plasma (P) are suggested to be interchangeable markers of neurodegeneration. However, evidence is scarce from community-based samples. NfL was examined in a small-scale sample of 287 individuals from the Gothenburg H70 Birth cohort 1944 study, using linear models in relation to CSF and magnetic resonance imaging (MRI) biomarker evidence of neurodegeneration. CSF-NfL and P-NfL present distinct associations with biomarker evidence of Alzheimer's disease (AD) pathology and neurodegeneration. P-NfL was associated with several markers that are characteristic of AD, including smaller hippocampal volumes, amyloid beta (A beta)(42), A beta(42/40), and A beta(42)/t-tau (total tau). CSF-NfL demonstrated associations with measures of synaptic and neurodegeneration, including t-tau, phosphorylated tau (p-tau), and neurogranin. Our findings suggest that P-NfL and CSF-NfL may exert different effects on markers of neurodegeneration in a small-scale community-based sample of 70-year-olds.
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| 9. |
- Erickson, Pontus, et al.
(författare)
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Prevalence and Clinical Implications of a β-Amyloid-Negative, Tau-Positive Cerebrospinal Fluid Biomarker Profile in Alzheimer Disease.
- 2023
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Ingår i: JAMA neurology. - 2168-6157. ; 80:9, s. 969-79
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Tidskriftsartikel (refereegranskat)abstract
- Knowledge is lacking on the prevalence and prognosis of individuals with a β-amyloid-negative, tau-positive (A-T+) cerebrospinal fluid (CSF) biomarker profile.To estimate the prevalence of a CSF A-T+ biomarker profile and investigate its clinical implications.This was a retrospective cohort study of the cross-sectional multicenter University of Gothenburg (UGOT) cohort (November 2019-January 2021), the longitudinal multicenter Alzheimer Disease Neuroimaging Initiative (ADNI) cohort (individuals with mild cognitive impairment [MCI] and no cognitive impairment; September 2005-May 2022), and 2 Wisconsin cohorts, Wisconsin Alzheimer Disease Research Center and Wisconsin Registry for Alzheimer Prevention (WISC; individuals without cognitive impairment; February 2007-November 2020). This was a multicenter study, with data collected from referral centers in clinical routine (UGOT) and research settings (ADNI and WISC). Eligible individuals had 1 lumbar puncture (all cohorts), 2 or more cognitive assessments (ADNI and WISC), and imaging (ADNI only) performed on 2 separate occasions. Data were analyzed on August 2022 to April 2023.Baseline CSF Aβ42/40 and phosphorylated tau (p-tau)181; cognitive tests (ADNI: modified preclinical Alzheimer cognitive composite [mPACC]; WISC: modified 3-test PACC [PACC-3]). Exposures in the ADNI cohort included [18F]-florbetapir amyloid positron emission tomography (PET), magnetic resonance imaging (MRI), [18F]-fluorodeoxyglucose PET (FDG-PET), and cross-sectional tau-PET (ADNI: [18F]-flortaucipir, WISC: [18F]-MK6240).Primary outcomes were the prevalence of CSF AT biomarker profiles and continuous longitudinal global cognitive outcome and imaging biomarker trajectories in A-T+ vs A-T- groups. Secondary outcomes included cross-sectional tau-PET.A total of 7679 individuals (mean [SD] age, 71.0 [8.4] years; 4101 male [53%]) were included in the UGOT cohort, 970 individuals (mean [SD] age, 73 [7.0] years; 526 male [54%]) were included in the ADNI cohort, and 519 individuals (mean [SD] age, 60 [7.3] years; 346 female [67%]) were included in the WISC cohort. The prevalence of an A-T+ profile in the UGOT cohort was 4.1% (95% CI, 3.7%-4.6%), being less common than the other patterns. Longitudinally, no significant differences in rates of worsening were observed between A-T+ and A-T- profiles for cognition or imaging biomarkers. Cross-sectionally, A-T+ had similar tau-PET uptake to individuals with an A-T- biomarker profile.Results suggest that the CSF A-T+ biomarker profile was found in approximately 5% of lumbar punctures and was not associated with a higher rate of cognitive decline or biomarker signs of disease progression compared with biomarker-negative individuals.
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| 10. |
- Gleerup, H. S., et al.
(författare)
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Saliva Neurofilament Light Chain Is Not a Diagnostic Biomarker for Neurodegeneration in a Mixed Memory Clinic Population
- 2021
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Ingår i: Frontiers in Aging Neuroscience. - : Frontiers Media SA. - 1663-4365. ; 13
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Tidskriftsartikel (refereegranskat)abstract
- Neurodegeneration and axonal injury result in an increasing release of neurofilament light chain (NfL) into bodily fluids, including cerebrospinal fluid (CSF) and blood. Numerous studies have shown that NfL levels in CSF and blood are increased in neurodegenerative disorders and monitor neurodegeneration. Saliva is an easily accessible biofluid that could be utilized as a biofluid measurement of Alzheimer's disease (AD) biomarkers. In this study, for the first time, salivary NfL was measured and compared to plasma NfL in a consecutive cohort of patients referred to cognitive assessments. In two mixed memory clinic cohorts, saliva samples were taken from 152 patients, AD (n = 49), mild cognitive impairment (MCI) (n = 47), non-AD (n = 56), and also 17 healthy controls. In addition, 135 also had a matching plasma sample. All saliva and plasma samples were analyzed for NfL, and the association between saliva and plasma NfL and CSF levels of total tau (t-tau), phosphorylated tau (p-tau), and beta amyloid 1-42 (A beta 42) were investigated. In total, 162/169 had quantifiable levels of salivary NfL by single molecule array (Simoa). No statistically significant differences were found in salivary NfL concentration across the diagnostic groups, but as expected, significant increases were found for plasma NfL in dementia cases (P < 0.0001). There was no association between saliva and plasma NfL levels. Furthermore, saliva NfL did not correlate with CSF A beta 42, p-tau, or tau concentrations. In conclusion, NfL is detectable in saliva but does not reflect neurodegeneration in the brain.
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