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Vos SJB, Delvenne A, Jack CR, Thal DR, Visser PJ. The clinical importance of suspected non-Alzheimer disease pathophysiology. Nat Rev Neurol 2024; 20:337-346. [PMID: 38724589 DOI: 10.1038/s41582-024-00962-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/04/2024] [Indexed: 06/06/2024]
Abstract
The development of biomarkers for Alzheimer disease (AD) has led to the origin of suspected non-AD pathophysiology (SNAP) - a heterogeneous biomarker-based concept that describes individuals with normal amyloid and abnormal tau and/or neurodegeneration biomarker status. In this Review, we describe the origins of the SNAP construct, along with its prevalence, diagnostic and prognostic implications, and underlying neuropathology. As we discuss, SNAP can be operationalized using different biomarker modalities, which could affect prevalence estimates and reported characteristics of SNAP in ways that are not yet fully understood. Moreover, the underlying aetiologies that lead to a SNAP biomarker profile, and whether SNAP is the same in people with and without cognitive impairment, remains unclear. Improved insight into the clinical characteristics and pathophysiology of SNAP is of major importance for research and clinical practice, as well as for trial design to optimize care and treatment of individuals with SNAP.
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Affiliation(s)
- Stephanie J B Vos
- Department of Psychiatry and Neuropsychology, Alzheimer Centrum Limburg, School for Mental Health and Neuroscience, Maastricht University, Maastricht, Netherlands.
| | - Aurore Delvenne
- Department of Psychiatry and Neuropsychology, Alzheimer Centrum Limburg, School for Mental Health and Neuroscience, Maastricht University, Maastricht, Netherlands
| | - Clifford R Jack
- Department of Radiology, Mayo Clinic and Foundation, Rochester, MN, USA
| | - Dietmar R Thal
- Laboratory for Neuropathology, Department of Imaging and Pathology and Leuven Brain Institute, KU Leuven, Leuven, Belgium
- Department of Pathology, University Hospital Leuven, Leuven, Belgium
| | - Pieter Jelle Visser
- Department of Psychiatry and Neuropsychology, Alzheimer Centrum Limburg, School for Mental Health and Neuroscience, Maastricht University, Maastricht, Netherlands
- Alzheimer Center Amsterdam, Department of Neurology, Amsterdam Neuroscience, Vrije Universiteit Amsterdam, Amsterdam UMC, Amsterdam, Netherlands
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Rizzi L, Balthazar MLF. Mini-review: The suspected non-Alzheimer's disease pathophysiology. Neurosci Lett 2021; 764:136208. [PMID: 34478819 DOI: 10.1016/j.neulet.2021.136208] [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] [Received: 07/18/2021] [Revised: 08/13/2021] [Accepted: 08/24/2021] [Indexed: 11/17/2022]
Abstract
Suspected non-Alzheimer's disease pathophysiology (SNAP) is a biomarker-based concept that underlying etiology has not been completely understood. Refers to a group of individuals that are negative for amyloid biomarkers and positive for p-Tau and/or neurodegeneration. SNAP causes great research interest because it is not clear if they have a different biological basis from Alzheimer's disease (AD), or are in an early stage of AD itself. The pathological processes behind SNAP need to be clarified. This mini-review aims to summarize the main characteristics of SNAP, besides reporting challenges and promising biomarkers related to the concept.
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Affiliation(s)
- Liara Rizzi
- Department of Neurology, University of Campinas (UNICAMP), Campinas, SP, Brazil.
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Biomarker profiles of Alzheimer's disease and dynamic of the association between cerebrospinal fluid levels of β-amyloid peptide and tau. PLoS One 2019; 14:e0217026. [PMID: 31086391 PMCID: PMC6516653 DOI: 10.1371/journal.pone.0217026] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2019] [Accepted: 05/02/2019] [Indexed: 02/07/2023] Open
Abstract
Objective To investigate the relationship between cerebrospinal fluid (CSF) β-amyloid peptide (Aβ42) and CSF Tau in a large population of patients referred to memory clinics for investigation of cognitive dysfunction. Methods We analyzed Alzheimer’s disease (AD) biomarkers in CSF taken from 3565 patients referred to 18 French memory clinics. Patients were classified into four profiles according to levels of CSF biomarkers (A: amyloidosis, N: neurodegeneration). The association between CSF Tau and CSF Aβ42 were analyzed using general linear regression models, in the overall population and stratified by biomarkers profiles. We compared linear and quadratic models using Akaike information criterion. We also assessed change in biomarker profiles in a subset of patients who had 2 assessments of biomarkers. Results CSF Tau was negatively associated with CSF Aβ42 in the overall population, following a non-linear quadratic model. However, the nature of this association was different in the 4 profiles: positive association in A-N- profile, negative association in A-N+ and A+N+ profiles, lack of association in A+N- patients. When considering patients with longitudinal data on profiles, 36% of those initially classified as A-N+ evolved to an A+N+ profile. Conclusions The nature of the association between CSF Aβ42 and CFS Tau depends on the A/N profiles of patients. These results suggest an increase in CSF Aβ42 early in the disease before its decline while tau pathology progresses, this pattern is particularly observed in non-APOE4 subjects. This phenomenon may explain why some patients with neurodegeneration only markers convert to an AD profile (A+N+) over time.
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Paquet C, Bouaziz-Amar E, Cognat E, Volpe-Gillot L, Haddad V, Mahieux F, Dekimeche S, Defontaines B, Chabriat H, Belin C, Texeira A, Goutagny S, Questel F, Azuar J, Sellier PO, Laplanche JL, Hugon J, Dumurgier J. Distribution of Cerebrospinal Fluid Biomarker Profiles in Patients Explored for Cognitive Disorders. J Alzheimers Dis 2018; 64:889-897. [DOI: 10.3233/jad-180240] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Affiliation(s)
- Claire Paquet
- Cognitive Neurology Center, Lariboisière – Fernand Widal Hospital, AP-HP, Paris, France
- Inserm U942, Universite Paris Diderot, Sorbonne Paris Cité, Paris, France
| | - Elodie Bouaziz-Amar
- Department of Biochemistry, Lariboisière – Fernand Widal Hospital, AP-HP, Paris, France
| | - Emmanuel Cognat
- Cognitive Neurology Center, Lariboisière – Fernand Widal Hospital, AP-HP, Paris, France
- Inserm U942, Universite Paris Diderot, Sorbonne Paris Cité, Paris, France
| | | | - Victor Haddad
- Department of Geriatrics, Saint Camille Hospital, Bry-sur-Marnes, France
| | - Florence Mahieux
- Department of Geriatrics, Sainte-Perrine Hospital, Paris, France
| | - Siham Dekimeche
- Departmentof Geriatrics, Les Gonesses Hospital, Gonesses, France
| | | | - Hugues Chabriat
- Department of Neurology, Lariboisière – Fernand Widal Hospital, AP-HP, Paris, France
| | | | - Antonio Texeira
- Department of Geriatrics, Lariboisière – Fernand Widal Hospital, AP-HP, Paris, France
| | | | - Frank Questel
- Department of Psychiatry, Lariboisière – Fernand Widal Hospital, AP-HP, Paris, France
| | - Julien Azuar
- Department of Psychiatry, Lariboisière – Fernand Widal Hospital, AP-HP, Paris, France
| | - Pierre-Olivier Sellier
- Department of Internal Medicine, Lariboisière – Fernand Widal Hospital, AP-HP, Paris, France
| | - Jean-Louis Laplanche
- Department of Biochemistry, Lariboisière – Fernand Widal Hospital, AP-HP, Paris, France
| | - Jacques Hugon
- Cognitive Neurology Center, Lariboisière – Fernand Widal Hospital, AP-HP, Paris, France
- Inserm U942, Universite Paris Diderot, Sorbonne Paris Cité, Paris, France
| | - Julien Dumurgier
- Cognitive Neurology Center, Lariboisière – Fernand Widal Hospital, AP-HP, Paris, France
- Inserm U942, Universite Paris Diderot, Sorbonne Paris Cité, Paris, France
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