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Meehan C, Lecocq S, Penner G. A reproducible approach for the use of aptamer libraries for the identification of Aptamarkers for brain amyloid deposition based on plasma analysis. PLoS One 2024; 19:e0307678. [PMID: 39190656 PMCID: PMC11349097 DOI: 10.1371/journal.pone.0307678] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2024] [Accepted: 07/10/2024] [Indexed: 08/29/2024] Open
Abstract
An approach for the agnostic identification and validation of aptamers for the prediction of a medical state from plasma analysis is presented in application to a key risk factor for Alzheimer's disease. brain amyloid deposition. This method involved the use of a newly designed aptamer library with sixteen random nucleotides interspersed with fixed sequences called a Neomer library. The Neomer library approach enables the direct application of the same starting library on multiple plasma samples, without the requirement for pre-enrichment associated with the traditional approach. Eight aptamers were identified as a result of the selection process and screened across 390 plasma samples by qPCR assay. Results were analysed using multiple machine learning algorithms from the Scikit-learn package along with clinical variables including cognitive status, age and sex to create predictive models. An Extra Trees Classifier model provided the highest predictive power. The Neomer approach resulted in a sensitivity of 0.88. specificity of 0.76. and AUC of 0.79. The only clinical variables that were included in the model were age and sex. We conclude that the Neomer approach represents a clear improvement for the agnostic identification of aptamers (Aptamarkers) that bind to unknown biomarkers of a medical state.
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Affiliation(s)
- Cathal Meehan
- NeoVentures Biotechnology Europe SAS, Villejuif Bio Park, Villejuif, France
| | - Soizic Lecocq
- NeoVentures Biotechnology Europe SAS, Villejuif Bio Park, Villejuif, France
| | - Gregory Penner
- NeoVentures Biotechnology Europe SAS, Villejuif Bio Park, Villejuif, France
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Lojo-Ramírez JA, Guerra-Gómez M, Marín-Cabañas AM, Fernández-Rodríguez P, Bernal Sánchez-Arjona M, Franco-Macías E, García-Solís D. Correlation Between Amyloid PET Imaging and Discordant Cerebrospinal Fluid Biomarkers Results in Patients with Suspected Alzheimer's Disease. J Alzheimers Dis 2024; 97:447-458. [PMID: 38143353 DOI: 10.3233/jad-230744] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2023]
Abstract
BACKGROUND Although the concordance between cerebrospinal fluid (CSF) Alzheimer's disease (AD) biomarkers and amyloid-PET findings is well known, there are no data regarding the concordance of amyloid-PET with inconclusive CSF values of amyloid-β (Aβ)1 - 42 and p-tau for the diagnosis of AD. OBJECTIVE To investigate the relationship between the amyloid-PET results with discordant AD biomarkers values in CSF (Aβ1 - 42+/p-tau-or Aβ1 - 42-/p-tau+). METHODS An observational retrospective study, including 62 patients with mild cognitive impairment (32/62) or dementia (30/62), suspicious of AD who had undergone a lumbar puncture to determine CSF AD biomarkers, and presented discordant values in CSF between Aβ1 - 42 and p-tau (Aβ1 - 42+/p-tau-or Aβ1 - 42-/p-tau+). All of them, underwent an amyloid-PET with 18F-Florbetaben. An extensive neuropsychological testing as part of their diagnostic process (MMSE and TMA-93), was performed, and it was also obtained the Global Deterioration Scale. RESULTS Comparing the discordant CSF results of each patient with the cerebral amyloid-PET results, we found that in the group with Aβ1 - 42+ and p-tau-CSF values, the amyloid-PET was positive in 51.2% and negative in 48.8% of patients, while in the group with Aβ1 - 42-and p-Tau+ CSF values, the amyloid-PET was positive in 52.6% of patients and negative in 47.4% of them. No significant association was found (p = 0.951) between the results of amyloid-PET and the two divergent groups in CSF. CONCLUSIONS No significant relationship was observed between the results of discordant AD biomarkers in CSF and the result of amyloid-PET. No trend in amyloid-PET results was observed in relation to CSF biomarker values.
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Affiliation(s)
| | - Miriam Guerra-Gómez
- Department of Nuclear Medicine, Virgen del Rocío University Hospital, Seville, Spain
| | | | | | | | - Emilio Franco-Macías
- Memory Unit, Department of Neurology, Virgen del Rocío University Hospital, Seville, Spain
| | - David García-Solís
- Department of Nuclear Medicine, Virgen del Rocío University Hospital, Seville, Spain
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Discordant Amyloid Status Diagnosis in Alzheimer’s Disease. Biomedicines 2022; 10:biomedicines10112880. [DOI: 10.3390/biomedicines10112880] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2022] [Revised: 11/04/2022] [Accepted: 11/07/2022] [Indexed: 11/12/2022] Open
Abstract
Introduction: Early and accurate Alzheimer’s disease (AD) diagnosis has evolved in recent years by the use of specific methods for detecting its histopathological features in concrete cases. Currently, biomarkers in cerebrospinal fluid (CSF) and imaging techniques (amyloid PET) are the most used specific methods. However, some results between both methods are discrepant. Therefore, an evaluation of these discrepant cases is required. Objective: The aim of this work is to analyze the characteristics of cases showing discrepancies between methods for detecting amyloid pathology. Methodology: Patients from the Neurology Department of La Fe Hospital (n = 82) were diagnosed using both methods (CSF biomarkers and amyloid-PET). Statistical analyses were performed using logistic regression, and sex and age were included as covariables. Additionally, results of standard neuropsychological evaluations were taken into account in our analyses. Results: The comparison between CSF biomarker (Aβ42) and amyloid PET results showed that around 18% of cases were discrepant—mainly CFS-negative and PET-positive cases had CSF levels close to the cut-off point. In addition, a correlation between the episodic memory test and CSF biomarkers levels was observed. However, the same results were not obtained for other neuropsychological domains. In general, CSF- and PET-discrepant cases showed altered episodic memory in around 66% of cases, while 33% showed normal performance. Conclusions: In common clinical practice at tertiary memory centers, result discrepancies between tests of amyloid status are far more common than expected. However, episodic memory tests remain an important support method for AD diagnosis, especially in cases with discrepant results between amyloid PET and CSF biomarkers.
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Bouwman FH, Frisoni GB, Johnson SC, Chen X, Engelborghs S, Ikeuchi T, Paquet C, Ritchie C, Bozeat S, Quevenco F, Teunissen C. Clinical application of CSF biomarkers for Alzheimer's disease: From rationale to ratios. ALZHEIMER'S & DEMENTIA (AMSTERDAM, NETHERLANDS) 2022; 14:e12314. [PMID: 35496374 PMCID: PMC9044123 DOI: 10.1002/dad2.12314] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/21/2021] [Revised: 03/01/2022] [Accepted: 03/28/2022] [Indexed: 12/15/2022]
Abstract
Biomarker testing is recommended for the accurate and timely diagnosis of Alzheimer's disease (AD). Using illustrative case narratives we consider how cerebrospinal fluid (CSF) biomarker tests may be used in different presentations of cognitive impairment to facilitate timely and differential diagnosis, improving diagnostic accuracy, providing prognostic information, and guiding personalized management in diverse scenarios. Evidence shows that (1) CSF ratios are superior to amyloid beta (Aβ)1-42 alone; (2) concordance of CSF ratios to amyloid positron emission tomography (PET) is better than Aβ1-42 alone; and (3) phosphorylated tau (p-tau)/Aβ1-42 ratio is superior to p-tau alone. CSF biomarkers are recommended for the exclusion of AD as the underlying cause of cognitive impairment, diagnosis of AD at an early stage, differential diagnosis of AD in individuals presenting with other neuropsychiatric symptoms, accurate diagnosis of AD in an atypical presentation, and for clinical trial enrichment. Highlights Cerebrospinal fluid (CSF) Alzheimer's disease (AD) biomarker testing may be underused outside specialist centers.CSF biomarkers improve diagnostic accuracy, guiding personalized management of AD.CSF ratios (amyloid beta [Aβ]1-42/Aβ1-40 and phosphorylated tau/Aβ1-42) perform better than single markers.CSF ratios produce fewer false-negative and false-positive results than individual markers.CSF biomarkers should be included in diagnostic work-up of AD and mild cognitive impairment due to AD.
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Affiliation(s)
- Femke H. Bouwman
- Alzheimer Center AmsterdamAmsterdam NeuroscienceAmsterdam UMCVrije Universiteit AmsterdamAmsterdamthe Netherlands
| | | | - Sterling C. Johnson
- University of Wisconsin‐Madison, and Geriatric Research Education and Clinical Center of the William S. Middleton Memorial Veterans HospitalMadisonWisconsinUSA
| | | | - Sebastiaan Engelborghs
- Center for Neurosciences (C4N)Vrije Universiteit Brussel, and Department of Neurology/Brussels Integrated Center for Brain and Memory (Bru‐BRAIN)Universitair Ziekenhuis Brussel, Brussels, and Department of Biomedical SciencesUniversity of AntwerpAntwerpBelgium
| | | | - Claire Paquet
- Université de ParisCognitive Neurology Center Lariboisière Hospital GHU APHP NordINSERMU1144ParisFrance
| | - Craig Ritchie
- University of Edinburgh, and Brain Health ScotlandEdinburghUK
| | | | | | - Charlotte Teunissen
- Department of Clinical ChemistryNeurochemistry LaboratoryAmsterdam NeuroscienceAmsterdam UMCVrije Universiteit AmsterdamAmsterdamthe Netherlands
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Gouilly D, Tisserand C, Nogueira L, Saint-Lary L, Rousseau V, Benaiteau M, Rafiq M, Carlier J, Milongo-Rigal E, Pagès JC, Pariente J. Taking the A Train? Limited Consistency of Aβ42 and the Aβ42/40 Ratio in the AT(N) Classification. J Alzheimers Dis 2021; 83:1033-1038. [PMID: 34397413 DOI: 10.3233/jad-210236] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
The consistency of cerebrospinal fluid amyloid-β (Aβ)42/40 ratio and Aβ 42 has not been assessed in the AT(N) classification system. We analyzed the classification changes of the dichotomized amyloid status (A+/A-) in 363 patients tested for Alzheimer's disease biomarkers after Aβ 42 was superseded by the Aβ 42/40 ratio. The consistency of Aβ 42 and the Aβ 42/40 ratio was very low. Notably, the proportions of "false" A+T-patients were considerable (74-91%) and corresponded mostly to patients not clinically diagnosed with Alzheimer's disease. Our results suggest that the interchangeability of Aβ 42/40 ratio and Aβ 42 is limited for classifying patients in clinical setting using the AT(N) scheme.
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Affiliation(s)
| | - Camille Tisserand
- Department of Cognitive Neurology, Epilepsy and Movement Disorders, CHU Toulouse Purpan, France
| | - Leonor Nogueira
- Department of Cell Biology and Cytology, CHU Toulouse Purpan, France
| | - Laura Saint-Lary
- Center of Clinical Investigation, CHU Toulouse Purpan (CIC1436), France
| | - Vanessa Rousseau
- Center of Clinical Investigation, CHU Toulouse Purpan (CIC1436), France
| | - Marie Benaiteau
- Department of Cognitive Neurology, Epilepsy and Movement Disorders, CHU Toulouse Purpan, France
| | - Marie Rafiq
- Department of Cognitive Neurology, Epilepsy and Movement Disorders, CHU Toulouse Purpan, France
| | - Jasmine Carlier
- Department of Cognitive Neurology, Epilepsy and Movement Disorders, CHU Toulouse Purpan, France
| | - Emilie Milongo-Rigal
- Department of Cognitive Neurology, Epilepsy and Movement Disorders, CHU Toulouse Purpan, France
| | | | - Jérémie Pariente
- Toulouse Neuroimaging Center, Toulouse, France.,Department of Cognitive Neurology, Epilepsy and Movement Disorders, CHU Toulouse Purpan, France
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Carrera-Muñoz I, Triguero-Cueva L, Romero-Fábrega JC, Triviño-Ibáñez EM, Vilchez-Carrillo R, Carnero-Pardo C, Gómez-Río M. PET-Amyloid After Inconclusive Cerebrospinal Fluid Biomarkers in Clinical Practice. Is it Necessary to Duplicate Procedures? Curr Alzheimer Res 2020; 17:698-708. [PMID: 33167840 DOI: 10.2174/1567205017666201109092637] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2020] [Revised: 09/01/2020] [Accepted: 10/13/2020] [Indexed: 11/22/2022]
Abstract
INTRODUCTION In the absence of a gold standard for in vivo Alzheimer disease (AD) diagnosis, AD biomarkers such as cerebrospinal fluid biomarkers (CSF-B) and PET-Amyloid are considered diagnostically useful in clinical practice guidelines and have consensual appropriate use criteria (AUC). However, little evidence has been published on their utilization in the clinical setting or on approaches to mismatched results. The objective of this work was to evaluate the use of AD biomarkers in clinical practice, focusing on the implementation of PET-Amyloid in cases of inconclusive CSF-B. METHODS This naturalistic, ambispective case series included patients fulfilling AUC for CSF-B and PET-Amyloid whose CSF-B results were non-diagnostic (target population), analyzing the diagnostic certainty, the treatment approach, and the relationship between CSF-B and PET-Amyloid results. RESULTS Out of 2373 eligible patients, AD biomarkers were studied in 417 (17.6%), most frequently due to cognitive impairment in under 65-year-olds, using CSF-B in 311 patients and PET-Amyloid in 150. CSF-B results were non-diagnostic for 44 patients (52.3% male; aged 60.9±6.6 years), who then underwent PET-Amyloid study, which was positive in 31. A 'k' coefficient of 0.108 was obtained between CSF-B and PET-amyloid (54.5% concordance). In multivariate regression analysis, Aβ42 was the only significant predictor (p= 0.018) of a positive PET-Amyloid result. In the target population, PETAmyloid increased diagnostic confidence by 53.7% (p <0.001) and modified the therapeutic approach in 36.4% of cases. CONCLUSION These findings support the duplication of AD biomarkers and demonstrate that the implementation of PET-Amyloid provides an early and certain diagnosis to guide appropriate treatment.
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Affiliation(s)
- Ismael Carrera-Muñoz
- Department of Neurology, Virgen de las Nieves University Hospital, Cognitive and Behavioral Neurology Unit,
Granada, Spain
| | - Lucía Triguero-Cueva
- Department of Neurology, Virgen de las Nieves University Hospital, Cognitive and Behavioral Neurology Unit,
Granada, Spain
| | - Juan C Romero-Fábrega
- Department of Neurology, Virgen de las Nieves University Hospital, Cognitive and Behavioral Neurology Unit,
Granada, Spain
| | - Eva M Triviño-Ibáñez
- Department of Nuclear Medicine, Virgen de las Nieves University Hospital, Granada, Spain
| | - Rosa Vilchez-Carrillo
- Department of Neurology, Virgen de las Nieves University Hospital, Cognitive and Behavioral Neurology Unit,
Granada, Spain
| | - Cristóbal Carnero-Pardo
- Fidyan Neurocenter, Granada, Spain,IBS Granada Bio-Health Research Institute, Granada, Spain
| | - Manuel Gómez-Río
- Department of Neurology, Virgen de las Nieves University Hospital, Cognitive and Behavioral Neurology Unit,
Granada, Spain,Department of Nuclear Medicine, Virgen de las Nieves University Hospital, Granada, Spain
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