Browsing by Author "Stoops, Erik"

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    Clinical and analytical comparison of six Simoa assays for plasma P-tau isoforms P-tau181, P-tau217, and P-tau231
    (BMC, 2021-12-04) Bayoumy, Sherif; Verberk, Inge M.W.; den Dulk, Ben; Hussainali, Zulaiga; Zwan, Marissa; van der Flier, Wiesje M.; Ashton, Nicholas J.; Zetterberg, Henrik; Blennow, Kaj; Vanbrabant, Jeroen; Stoops, Erik; Vanmechelen, Eugeen; Dage, Jeffrey L.; Teunissen, Charlotte E.; Neurology, School of Medicine
    Introduction: Studies using different assays and technologies showed highly promising diagnostic value of plasma phosphorylated (P-)tau levels for Alzheimer's disease (AD). We aimed to compare six P-tau Simoa assays, including three P-tau181 (Eli Lilly, ADx, Quanterix), one P-tau217 (Eli Lilly), and two P-tau231 (ADx, Gothenburg). Methods: We studied the analytical (sensitivity, precision, parallelism, dilution linearity, and recovery) and clinical (40 AD dementia patients, age 66±8years, 50%F; 40 age- and sex-matched controls) performance of the assays. Results: All assays showed robust analytical performance, and particularly P-tau217 Eli Lilly; P-tau231 Gothenburg and all P-tau181 assays showed robust clinical performance to differentiate AD from controls, with AUCs 0.936-0.995 (P-tau231 ADx: AUC = 0.719). Results obtained with all P-tau181 assays, P-tau217 Eli Lilly assay, and P-tau231 Gothenburg assay strongly correlated (Spearman's rho > 0.86), while correlations with P-tau231 ADx results were moderate (rho < 0.65). Discussion: P-tau isoforms can be measured robustly by several novel high-sensitive Simoa assays.
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    Plasma and CSF biomarkers in a memory clinic: Head-to-head comparison of phosphorylated tau immunoassays
    (Wiley, 2023) Ashton, Nicholas J.; Puig-Pijoan, Albert; Milà-Alomà, Marta; Fernández-Lebrero, Aida; García-Escobar, Greta; González-Ortiz, Fernándo; Kac, Przemysław R.; Brum, Wagner S.; Benedet, Andréa L.; Lantero-Rodriguez, Juan; Day, Theresa A.; Vanbrabant, Jeroen; Stoops, Erik; Vanmechelen, Eugeen; Triana-Baltzer, Gallen; Moughadam, Setareh; Kolb, Hartmuth; Ortiz-Romero, Paula; Karikari, Thomas K.; Minguillon, Carolina; Hernández Sánchez, Juan José; Navalpotro-Gómez, Irene; Grau-Rivera, Oriol; Manero, Rosa María; Puente-Periz, Víctor; de la Torre, Rafael; Roquer, Jaume; Dage, Jeff L.; Zetterberg, Henrik; Blennow, Kaj; Suárez-Calvet, Marc; Neurology, School of Medicine
    Introduction: Direct comparisons of the main blood phosphorylated tau immunoassays in memory clinic populations are needed to understand possible differences. Methods: In the BIODEGMAR study, 197 participants presenting with cognitive complaints were classified into an Alzheimer's disease (AD) or a non-AD cerebrospinal fluid (CSF) profile group, according to their amyloid beta 42/ phosphorylated tau (Aβ42/p-tau) ratio. We performed a head-to-head comparison of nine plasma and nine CSF tau immunoassays and determined their accuracy to discriminate abnormal CSF Aβ42/p-tau ratio. Results: All studied plasma tau biomarkers were significantly higher in the AD CSF profile group compared to the non-AD CSF profile group and significantly discriminated abnormal CSF Aβ42/p-tau ratio. For plasma p-tau biomarkers, the higher discrimination accuracy was shown by Janssen p-tau217 (r = 0.76; area under the curve [AUC] = 0.96), ADx p-tau181 (r = 0.73; AUC = 0.94), and Lilly p-tau217 (r = 0.73; AUC = 0.94). Discussion: Several plasma p-tau biomarkers can be used in a specialized memory clinic as a stand-alone biomarker to detect biologically-defined AD. Highlights: Patients with an Alzheimer's disease cerebrospinal fluid (AD CSF) profile have higher plasma phosphorylated tau (p-tau) levels than the non-AD CSF profile group. All plasma p-tau biomarkers significantly discriminate patients with an AD CSF profile from the non-AD CSF profile group. Janssen p-tau217, ADx p-tau181, and Lilly p-tau217 in plasma show the highest accuracy to detect biologically defined AD. Janssen p-tau217, ADx p-tau181, Lilly p-tau217, Lilly p-tau181, and UGot p-tau231 in plasma show performances that are comparable to their CSF counterparts.
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    Plasma biomarkers predict amyloid pathology in cognitively normal monozygotic twins after 10 years
    (Oxford University Press, 2023-02-04) den Braber, Anouk; Verberk, Inge M. W.; Tomassen, Jori; den Dulk, Ben; Stoops, Erik; Dage, Jeffrey L.; Collij, Lyduine E.; Barkhof, Frederik; Willemsen, Gonneke; Nivard, Michel G.; van Berckel, Bart N. M.; Scheltens, Philip; Visser, Pieter Jelle; de Geus, Eco J. C.; Teunissen, Charlotte E.; Neurology, School of Medicine
    Blood-based biomarkers could prove useful to predict Alzheimer's disease core pathologies in advance of clinical symptoms. Implementation of such biomarkers requires a solid understanding of their long-term dynamics and the contribution of confounding to their association with Alzheimer's disease pathology. Here we assess the value of plasma amyloid-β1-42/1-40, phosphorylated-tau181 and glial fibrillary acidic protein to detect early Alzheimer's disease pathology, accounting for confounding by genetic and early environmental factors. Participants were 200 monozygotic twins, aged ≥60 years with normal cognition from the european medical information framework for Alzheimer's disease study. All twins had amyloid-β status and plasma samples available at study enrolment. For 80 twins, additional plasma samples were available that had been collected approximately 10 years prior to amyloid-β status assessment. Single-molecule array assays were applied to measure amyloid-β1-42/1-40, phosphorylated-tau181 and glial fibrillary acidic protein. Predictive value of and longitudinal change in these biomarkers were assessed using receiver operating characteristic curve analysis and linear mixed models. Amyloid pathology could be predicted using blood-based biomarkers obtained at the time of amyloid status assessment (amyloid-β1-42/1-40: area under the curve = 0.65, P = 0.01; phosphorylated-tau181: area under the curve = 0.84, P < 0.001; glial fibrillary acidic protein: area under the curve = 0.74, P < 0.001), as well as using those obtained 10 years prior to amyloid status assessment (amyloid-β1-42/1-40: area under the curve = 0.69, P = 0.03; phosphorylated-tau181: area under the curve = 0.92, P < 0.001; glial fibrillary acidic protein: area under the curve = 0.84, P < 0.001). Longitudinally, amyloid-β1-42/1-40 levels decreased [β (SE) = -0.12 (0.01), P < 0.001] and phosphorylated-tau181 levels increased [β (SE) = 0.02 (0.01), P = 0.004]. Amyloid-β-positive individuals showed a steeper increase in phosphorylated-tau181 compared with amyloid-β-negative individuals [β (SE) = 0.06 (0.02), P = 0.004]. Also amyloid-β-positive individuals tended to show a steeper increase in glial fibrillary acidic protein [β (SE) = 0.04 (0.02), P = 0.07]. Within monozygotic twin pairs, those with higher plasma phosphorylated-tau181 and lower amyloid-β1-42/1-40 levels were more likely to be amyloid-β positive [β (SE) = 0.95 (0.26), P < 0.001; β (SE) = -0.28 (0.14), P < 0.05] indicating minimal contribution of confounding by genetic and early environmental factors. Our data support the use of amyloid-β1-42/1-40, phosphorylated-tau181 and glial fibrillary acidic protein as screening tools for Alzheimer's disease pathology in the normal aging population, which is of importance for enrolment of high-risk subjects in secondary, or even primary, prevention trials. Furthermore, these markers show potential as low-invasive monitoring tool of disease progression and possibly treatment effects in clinical trials.
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    The global Alzheimer's Association round robin study on plasma amyloid β methods
    (Wiley, 2021-10-14) Pannee, Josef; Shaw, Leslie M.; Korecka, Magdalena; Waligorska, Teresa; Teunissen, Charlotte E.; Stoops, Erik; Vanderstichele, Hugo M. J.; Mauroo, Kimberley; Verberk, Inge M. W.; Keshavan, Ashvini; Pesini, Pedro; Sarasa, Leticia; Pascual-Lucas, Maria; Fandos, Noelia; Allué, José-Antonio; Portelius, Erik; Andreasson, Ulf; Yoda, Ritsuko; Nakamura, Akinori; Kaneko, Naoki; Yang, Shieh-Yueh; Liu, Huei-Chun; Palme, Stefan; Bittner, Tobias; Mawuenyega, Kwasi G.; Ovod, Vitaliy; Bollinger, James; Bateman, Randall J.; Li, Yan; Dage, Jeffrey L.; Stomrud, Erik; Hansson, Oskar; Schott, Jonathan M.; Blennow, Kaj; Zetterberg, Henrik; Neurology, School of Medicine
    Introduction: Blood-based assays to measure brain amyloid beta (Aβ) deposition are an attractive alternative to the cerebrospinal fluid (CSF)-based assays currently used in clinical settings. In this study, we examined different blood-based assays to measure Aβ and how they compare among centers and assays. Methods: Aliquots from 81 plasma samples were distributed to 10 participating centers. Seven immunological assays and four mass-spectrometric methods were used to measure plasma Aβ concentrations. Results: Correlations were weak for Aβ42 while Aβ40 correlations were stronger. The ratio Aβ42/Aβ40 did not improve the correlations and showed weak correlations. Discussion: The poor correlations for Aβ42 in plasma might have several potential explanations, such as the high levels of plasma proteins (compared to CSF), sensitivity to pre-analytical sample handling and specificity, and cross-reactivity of different antibodies. Different methods might also measure different pools of plasma Aβ42. We, however, hypothesize that greater correlations might be seen in future studies because many of the methods have been refined during completion of this study.