Quantification of total apolipoprotein E and its isoforms in cerebrospinal fluid from patients with neurodegenerative diseases

Abstract Background The human APOE gene, which codes for apolipoprotein E (apoE), has three major polymorphic alleles: ε2, ε3, and ε4 that give rise to amino acid substitutions. APOE-ε4 is a strong risk factor of sporadic Alzheimer’s disease (AD) but the reason why is still unknown despite intense r...

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Main Authors: K. Minta, G. Brinkmalm, S. Janelidze, S. Sjödin, E. Portelius, E. Stomrud, H. Zetterberg, K. Blennow, O. Hansson, U. Andreasson
Format: Article
Language:English
Published: BMC 2020-02-01
Series:Alzheimer’s Research & Therapy
Subjects:
Online Access:https://doi.org/10.1186/s13195-020-00585-7
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author K. Minta
G. Brinkmalm
S. Janelidze
S. Sjödin
E. Portelius
E. Stomrud
H. Zetterberg
K. Blennow
O. Hansson
U. Andreasson
author_facet K. Minta
G. Brinkmalm
S. Janelidze
S. Sjödin
E. Portelius
E. Stomrud
H. Zetterberg
K. Blennow
O. Hansson
U. Andreasson
author_sort K. Minta
collection DOAJ
description Abstract Background The human APOE gene, which codes for apolipoprotein E (apoE), has three major polymorphic alleles: ε2, ε3, and ε4 that give rise to amino acid substitutions. APOE-ε4 is a strong risk factor of sporadic Alzheimer’s disease (AD) but the reason why is still unknown despite intense research for more than 20 years. The aim of the study was to investigate if the concentrations of total apoE and the specific apoE isoforms in cerebrospinal fluid (CSF) differ between various neurodegenerative diseases and control individuals, as well as among the APOE genotypes. Methods Quantification of total apoE and specific apoE isoforms (E2, E3, and E4) in CSF was performed using high-resolution parallel reaction monitoring mass spectrometry. In total, 1820 individuals were involved in the study including clinically diagnosed AD patients (n = 228), cognitively unimpaired (CU) patients (n = 896), and patients with other neurodegenerative disorders (n = 696). Follow-up data was available for 100 individuals, assessed at two time points. Subjects were dichotomized based on an Aβ42/40 CSF concentration ratio cut-off into Aβ positive (Aβ+, < 0.091) and Aβ negative (Aβ−, > 0.091) groups. Results Even though there was a significant increase of total apoE in the amyloid β-positive (Aβ+) group compared with amyloid β-negative (Aβ−) individuals (p < 0.001), the magnitude of the effect was very small (AUC = 0.55). Moreover, CSF total apoE concentrations did not differ between Aβ− CU controls and clinically diagnosed AD patients. There was a difference in concentration between isoforms in heterozygous individuals in an isoform-dependent manner (E2 < E3 < E4) (p < 0.001, AUC = 0.64–0.69), and these associations remained when dichotomizing the samples into Aβ+ and Aβ− groups (p < 0.01, AUC = 0.63–0.74). In the cohort with follow-up samples, neither total apoE nor isoform-specific apoE concentrations differed between the two time points (p > 0.05). Conclusions The results indicate that neither the concentrations of total apoE nor the different apoE isoforms in CSF are associated with APOE-ε4 carrier status, Aβ status, or clinical dementia diagnoses.
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spelling doaj.art-1cc063aa72d2400893123db4cd563d4b2022-12-21T22:44:17ZengBMCAlzheimer’s Research & Therapy1758-91932020-02-0112111110.1186/s13195-020-00585-7Quantification of total apolipoprotein E and its isoforms in cerebrospinal fluid from patients with neurodegenerative diseasesK. Minta0G. Brinkmalm1S. Janelidze2S. Sjödin3E. Portelius4E. Stomrud5H. Zetterberg6K. Blennow7O. Hansson8U. Andreasson9Department of Psychiatry and Neurochemistry, Institute of Neuroscience and Physiology, the Sahlgrenska Academy at the University of GothenburgDepartment of Psychiatry and Neurochemistry, Institute of Neuroscience and Physiology, the Sahlgrenska Academy at the University of GothenburgClinical Memory Research Unit, Department of Clinical Sciences, Lund UniversityDepartment of Psychiatry and Neurochemistry, Institute of Neuroscience and Physiology, the Sahlgrenska Academy at the University of GothenburgDepartment of Psychiatry and Neurochemistry, Institute of Neuroscience and Physiology, the Sahlgrenska Academy at the University of GothenburgClinical Memory Research Unit, Department of Clinical Sciences, Lund UniversityDepartment of Psychiatry and Neurochemistry, Institute of Neuroscience and Physiology, the Sahlgrenska Academy at the University of GothenburgDepartment of Psychiatry and Neurochemistry, Institute of Neuroscience and Physiology, the Sahlgrenska Academy at the University of GothenburgClinical Memory Research Unit, Department of Clinical Sciences, Lund UniversityDepartment of Psychiatry and Neurochemistry, Institute of Neuroscience and Physiology, the Sahlgrenska Academy at the University of GothenburgAbstract Background The human APOE gene, which codes for apolipoprotein E (apoE), has three major polymorphic alleles: ε2, ε3, and ε4 that give rise to amino acid substitutions. APOE-ε4 is a strong risk factor of sporadic Alzheimer’s disease (AD) but the reason why is still unknown despite intense research for more than 20 years. The aim of the study was to investigate if the concentrations of total apoE and the specific apoE isoforms in cerebrospinal fluid (CSF) differ between various neurodegenerative diseases and control individuals, as well as among the APOE genotypes. Methods Quantification of total apoE and specific apoE isoforms (E2, E3, and E4) in CSF was performed using high-resolution parallel reaction monitoring mass spectrometry. In total, 1820 individuals were involved in the study including clinically diagnosed AD patients (n = 228), cognitively unimpaired (CU) patients (n = 896), and patients with other neurodegenerative disorders (n = 696). Follow-up data was available for 100 individuals, assessed at two time points. Subjects were dichotomized based on an Aβ42/40 CSF concentration ratio cut-off into Aβ positive (Aβ+, < 0.091) and Aβ negative (Aβ−, > 0.091) groups. Results Even though there was a significant increase of total apoE in the amyloid β-positive (Aβ+) group compared with amyloid β-negative (Aβ−) individuals (p < 0.001), the magnitude of the effect was very small (AUC = 0.55). Moreover, CSF total apoE concentrations did not differ between Aβ− CU controls and clinically diagnosed AD patients. There was a difference in concentration between isoforms in heterozygous individuals in an isoform-dependent manner (E2 < E3 < E4) (p < 0.001, AUC = 0.64–0.69), and these associations remained when dichotomizing the samples into Aβ+ and Aβ− groups (p < 0.01, AUC = 0.63–0.74). In the cohort with follow-up samples, neither total apoE nor isoform-specific apoE concentrations differed between the two time points (p > 0.05). Conclusions The results indicate that neither the concentrations of total apoE nor the different apoE isoforms in CSF are associated with APOE-ε4 carrier status, Aβ status, or clinical dementia diagnoses.https://doi.org/10.1186/s13195-020-00585-7Alzheimer’s diseaseApolipoprotein ECerebrospinal fluidMass spectrometry
spellingShingle K. Minta
G. Brinkmalm
S. Janelidze
S. Sjödin
E. Portelius
E. Stomrud
H. Zetterberg
K. Blennow
O. Hansson
U. Andreasson
Quantification of total apolipoprotein E and its isoforms in cerebrospinal fluid from patients with neurodegenerative diseases
Alzheimer’s Research & Therapy
Alzheimer’s disease
Apolipoprotein E
Cerebrospinal fluid
Mass spectrometry
title Quantification of total apolipoprotein E and its isoforms in cerebrospinal fluid from patients with neurodegenerative diseases
title_full Quantification of total apolipoprotein E and its isoforms in cerebrospinal fluid from patients with neurodegenerative diseases
title_fullStr Quantification of total apolipoprotein E and its isoforms in cerebrospinal fluid from patients with neurodegenerative diseases
title_full_unstemmed Quantification of total apolipoprotein E and its isoforms in cerebrospinal fluid from patients with neurodegenerative diseases
title_short Quantification of total apolipoprotein E and its isoforms in cerebrospinal fluid from patients with neurodegenerative diseases
title_sort quantification of total apolipoprotein e and its isoforms in cerebrospinal fluid from patients with neurodegenerative diseases
topic Alzheimer’s disease
Apolipoprotein E
Cerebrospinal fluid
Mass spectrometry
url https://doi.org/10.1186/s13195-020-00585-7
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