1
|
Dupulthys S, Dujardin K, Anné W, Pollet P, Vanhaverbeke M, McAuliffe D, Lammertyn PJ, Berteloot L, Mertens N, De Jaeger P. Single-lead electrocardiogram Artificial Intelligence model with risk factors detects atrial fibrillation during sinus rhythm. Europace 2024; 26:euad354. [PMID: 38079535 PMCID: PMC10872711 DOI: 10.1093/europace/euad354] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2023] [Accepted: 11/22/2023] [Indexed: 02/18/2024] Open
Abstract
AIMS Guidelines recommend opportunistic screening for atrial fibrillation (AF), using a 30 s single-lead electrocardiogram (ECG) recorded by a wearable device. Since many patients have paroxysmal AF, identification of patients at high risk presenting with sinus rhythm (SR) may increase the yield of subsequent long-term cardiac monitoring. The aim is to evaluate an AI-algorithm trained on 10 s single-lead ECG with or without risk factors to predict AF. METHODS AND RESULTS This retrospective study used 13 479 ECGs from AF patients in SR around the time of diagnosis and 53 916 age- and sex-matched control ECGs, augmented with 17 risk factors extracted from electronic health records. AI models were trained and compared using 1- or 12-lead ECGs, with or without risk factors. Model bias was evaluated by age- and sex-stratification of results. Random forest models identified the most relevant risk factors. The single-lead model achieved an area under the curve of 0.74, which increased to 0.76 by adding six risk factors (95% confidence interval: 0.74-0.79). This model matched the performance of a 12-lead model. Results are stable for both sexes, over ages ranging from 40 to 90 years. Out of 17 clinical variables, 6 were sufficient for optimal accuracy of the model: hypertension, heart failure, valvular disease, history of myocardial infarction, age, and sex. CONCLUSION An AI model using a single-lead SR ECG and six risk factors can identify patients with concurrent AF with similar accuracy as a 12-lead ECG-AI model. An age- and sex-matched data set leads to an unbiased model with consistent predictions across age groups.
Collapse
Affiliation(s)
- Stijn Dupulthys
- RADar Learning and Innovation Centre, AZ Delta, Deltalaan 1, 8800 Roeselare, Belgium
| | - Karl Dujardin
- Department of Cardiology, AZ Delta, Roeselare, Belgium
| | - Wim Anné
- Department of Cardiology, AZ Delta, Roeselare, Belgium
| | - Peter Pollet
- Department of Cardiology, AZ Delta, Roeselare, Belgium
| | | | | | - Pieter-Jan Lammertyn
- RADar Learning and Innovation Centre, AZ Delta, Deltalaan 1, 8800 Roeselare, Belgium
| | - Louise Berteloot
- RADar Learning and Innovation Centre, AZ Delta, Roeselare, Belgium
| | - Nathalie Mertens
- RADar Learning and Innovation Centre, AZ Delta, Deltalaan 1, 8800 Roeselare, Belgium
| | - Peter De Jaeger
- RADar Learning and Innovation Centre, AZ Delta, Deltalaan 1, 8800 Roeselare, Belgium
- Department of Medicine and Life Sciences, Hasselt University, Martelarenlaan 42, 3500 Hasselt, Belgium
| |
Collapse
|
2
|
Michiels L, Thijs L, Mertens N, Sunaert S, Vandenbulcke M, Bormans G, Verheyden G, Koole M, Van Laere K, Lemmens R. In Vivo Detection of Neurofibrillary Tangles by 18F-MK-6240 PET/MR in Patients With Ischemic Stroke. Neurology 2023; 100:e62-e71. [PMID: 36302665 DOI: 10.1212/wnl.0000000000201344] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2022] [Accepted: 08/17/2022] [Indexed: 12/31/2022] Open
Abstract
BACKGROUND AND OBJECTIVES The risk of developing Alzheimer disease is increased after stroke, and this association may not solely be driven by traditional vascular risk factors. Neuronal death leads to the release of tau proteins, which can become dephosphorylated, rephosphorylated, or hyperphosphorylated in the setting of ischemia, possibly leading to formation of neurofibrillary tangles (NFT). Therefore, a potential synergistic effect between development of tauopathy and cerebrovascular lesion burden may contribute to cognitive decline after stroke. We explored the spatial and temporal distribution of NFT after ischemic stroke in vivo by using 18F-MK-6240 PET. METHODS We included patients with a first ischemic stroke to undergo longitudinal 18F-MK-6240 PET/MR within 2-4 weeks and 6 months after stroke. For cross-sectional analyses, we also included age-matched healthy controls. We delineated 5 volumes of interest based on T2 FLAIR and T1 MR data: the ischemic lesion, 3 consecutive peri-ischemic areas, and the remaining ipsilesional hemisphere. We performed region-based voxel-wise partial volume correction on the PET data and calculated standardized uptake value ratios (SUVRs) with the cerebellum as the reference region. RESULTS We did not quantify PET scans of patients within the first month after stroke (n = 17; median age 73 years [interquartile range {IQR}: 62-82 years]) because the signal intensity was influenced by blood-brain barrier breakdown hampering a reliable data analysis. At 6 months after the event (n = 13; median age 71 years [IQR: 60-79 years]), 18F-MK-6240 SUVR was increased in the ischemic lesion compared with 20 age-matched healthy controls (median age 71.5 years [IQR: 66-76 years]; ratiolesion/controls = 1.62 ± 0.54; 1-sample t test: p = 0.0015) and gradually decreased in the surrounding tissue (1-way within-subject analysis of variance [F{1.2, 14.8} = 18.0, p = 0.00043]). DISCUSSION These findings suggest that NFT may form after ischemic stroke and spread in the peri-ischemic brain parenchyma. Further follow-up is required to gain more insight into the spatial and temporal dynamics of this tauopathy after ischemic stroke.
Collapse
Affiliation(s)
- Laura Michiels
- From the Department of Neurosciences (L.M., S.S., M.V., R.L.), Leuven Brain Institute, Belgium; VIB, Center for Brain & Disease Research (L.M., R.L), Laboratory of Neurobiology, Belgium; Department of Neurology (L.M., R.L.), University Hospitals Leuven, Belgium; Department of Rehabilitation Sciences (L.T., G.V.), KU Leuven, Belgium; Nuclear Medicine and Molecular Imaging (N.M., M.K., K.V.L.), Department of Imaging and Pathology, KU Leuven, Belgium; Translational MRI (S.S.), Department of Imaging and Pathology, KU Leuven, Belgium; Department of Radiology (S.S.), University Hospitals Leuven, Belgium; Department of Geriatric Psychiatry (M.V.), University Psychiatric Centre, KU Leuven, Belgium; Department of Pharmaceutical and Pharmacological Sciences (G.B.), KU Leuven, Belgium; and Division of Nuclear Medicine (K.V.L.), University Hospitals Leuven, Belgium.
| | - Liselot Thijs
- From the Department of Neurosciences (L.M., S.S., M.V., R.L.), Leuven Brain Institute, Belgium; VIB, Center for Brain & Disease Research (L.M., R.L), Laboratory of Neurobiology, Belgium; Department of Neurology (L.M., R.L.), University Hospitals Leuven, Belgium; Department of Rehabilitation Sciences (L.T., G.V.), KU Leuven, Belgium; Nuclear Medicine and Molecular Imaging (N.M., M.K., K.V.L.), Department of Imaging and Pathology, KU Leuven, Belgium; Translational MRI (S.S.), Department of Imaging and Pathology, KU Leuven, Belgium; Department of Radiology (S.S.), University Hospitals Leuven, Belgium; Department of Geriatric Psychiatry (M.V.), University Psychiatric Centre, KU Leuven, Belgium; Department of Pharmaceutical and Pharmacological Sciences (G.B.), KU Leuven, Belgium; and Division of Nuclear Medicine (K.V.L.), University Hospitals Leuven, Belgium
| | - Nathalie Mertens
- From the Department of Neurosciences (L.M., S.S., M.V., R.L.), Leuven Brain Institute, Belgium; VIB, Center for Brain & Disease Research (L.M., R.L), Laboratory of Neurobiology, Belgium; Department of Neurology (L.M., R.L.), University Hospitals Leuven, Belgium; Department of Rehabilitation Sciences (L.T., G.V.), KU Leuven, Belgium; Nuclear Medicine and Molecular Imaging (N.M., M.K., K.V.L.), Department of Imaging and Pathology, KU Leuven, Belgium; Translational MRI (S.S.), Department of Imaging and Pathology, KU Leuven, Belgium; Department of Radiology (S.S.), University Hospitals Leuven, Belgium; Department of Geriatric Psychiatry (M.V.), University Psychiatric Centre, KU Leuven, Belgium; Department of Pharmaceutical and Pharmacological Sciences (G.B.), KU Leuven, Belgium; and Division of Nuclear Medicine (K.V.L.), University Hospitals Leuven, Belgium
| | - Stefan Sunaert
- From the Department of Neurosciences (L.M., S.S., M.V., R.L.), Leuven Brain Institute, Belgium; VIB, Center for Brain & Disease Research (L.M., R.L), Laboratory of Neurobiology, Belgium; Department of Neurology (L.M., R.L.), University Hospitals Leuven, Belgium; Department of Rehabilitation Sciences (L.T., G.V.), KU Leuven, Belgium; Nuclear Medicine and Molecular Imaging (N.M., M.K., K.V.L.), Department of Imaging and Pathology, KU Leuven, Belgium; Translational MRI (S.S.), Department of Imaging and Pathology, KU Leuven, Belgium; Department of Radiology (S.S.), University Hospitals Leuven, Belgium; Department of Geriatric Psychiatry (M.V.), University Psychiatric Centre, KU Leuven, Belgium; Department of Pharmaceutical and Pharmacological Sciences (G.B.), KU Leuven, Belgium; and Division of Nuclear Medicine (K.V.L.), University Hospitals Leuven, Belgium
| | - Mathieu Vandenbulcke
- From the Department of Neurosciences (L.M., S.S., M.V., R.L.), Leuven Brain Institute, Belgium; VIB, Center for Brain & Disease Research (L.M., R.L), Laboratory of Neurobiology, Belgium; Department of Neurology (L.M., R.L.), University Hospitals Leuven, Belgium; Department of Rehabilitation Sciences (L.T., G.V.), KU Leuven, Belgium; Nuclear Medicine and Molecular Imaging (N.M., M.K., K.V.L.), Department of Imaging and Pathology, KU Leuven, Belgium; Translational MRI (S.S.), Department of Imaging and Pathology, KU Leuven, Belgium; Department of Radiology (S.S.), University Hospitals Leuven, Belgium; Department of Geriatric Psychiatry (M.V.), University Psychiatric Centre, KU Leuven, Belgium; Department of Pharmaceutical and Pharmacological Sciences (G.B.), KU Leuven, Belgium; and Division of Nuclear Medicine (K.V.L.), University Hospitals Leuven, Belgium
| | - Guy Bormans
- From the Department of Neurosciences (L.M., S.S., M.V., R.L.), Leuven Brain Institute, Belgium; VIB, Center for Brain & Disease Research (L.M., R.L), Laboratory of Neurobiology, Belgium; Department of Neurology (L.M., R.L.), University Hospitals Leuven, Belgium; Department of Rehabilitation Sciences (L.T., G.V.), KU Leuven, Belgium; Nuclear Medicine and Molecular Imaging (N.M., M.K., K.V.L.), Department of Imaging and Pathology, KU Leuven, Belgium; Translational MRI (S.S.), Department of Imaging and Pathology, KU Leuven, Belgium; Department of Radiology (S.S.), University Hospitals Leuven, Belgium; Department of Geriatric Psychiatry (M.V.), University Psychiatric Centre, KU Leuven, Belgium; Department of Pharmaceutical and Pharmacological Sciences (G.B.), KU Leuven, Belgium; and Division of Nuclear Medicine (K.V.L.), University Hospitals Leuven, Belgium
| | - Geert Verheyden
- From the Department of Neurosciences (L.M., S.S., M.V., R.L.), Leuven Brain Institute, Belgium; VIB, Center for Brain & Disease Research (L.M., R.L), Laboratory of Neurobiology, Belgium; Department of Neurology (L.M., R.L.), University Hospitals Leuven, Belgium; Department of Rehabilitation Sciences (L.T., G.V.), KU Leuven, Belgium; Nuclear Medicine and Molecular Imaging (N.M., M.K., K.V.L.), Department of Imaging and Pathology, KU Leuven, Belgium; Translational MRI (S.S.), Department of Imaging and Pathology, KU Leuven, Belgium; Department of Radiology (S.S.), University Hospitals Leuven, Belgium; Department of Geriatric Psychiatry (M.V.), University Psychiatric Centre, KU Leuven, Belgium; Department of Pharmaceutical and Pharmacological Sciences (G.B.), KU Leuven, Belgium; and Division of Nuclear Medicine (K.V.L.), University Hospitals Leuven, Belgium
| | - Michel Koole
- From the Department of Neurosciences (L.M., S.S., M.V., R.L.), Leuven Brain Institute, Belgium; VIB, Center for Brain & Disease Research (L.M., R.L), Laboratory of Neurobiology, Belgium; Department of Neurology (L.M., R.L.), University Hospitals Leuven, Belgium; Department of Rehabilitation Sciences (L.T., G.V.), KU Leuven, Belgium; Nuclear Medicine and Molecular Imaging (N.M., M.K., K.V.L.), Department of Imaging and Pathology, KU Leuven, Belgium; Translational MRI (S.S.), Department of Imaging and Pathology, KU Leuven, Belgium; Department of Radiology (S.S.), University Hospitals Leuven, Belgium; Department of Geriatric Psychiatry (M.V.), University Psychiatric Centre, KU Leuven, Belgium; Department of Pharmaceutical and Pharmacological Sciences (G.B.), KU Leuven, Belgium; and Division of Nuclear Medicine (K.V.L.), University Hospitals Leuven, Belgium
| | - Koen Van Laere
- From the Department of Neurosciences (L.M., S.S., M.V., R.L.), Leuven Brain Institute, Belgium; VIB, Center for Brain & Disease Research (L.M., R.L), Laboratory of Neurobiology, Belgium; Department of Neurology (L.M., R.L.), University Hospitals Leuven, Belgium; Department of Rehabilitation Sciences (L.T., G.V.), KU Leuven, Belgium; Nuclear Medicine and Molecular Imaging (N.M., M.K., K.V.L.), Department of Imaging and Pathology, KU Leuven, Belgium; Translational MRI (S.S.), Department of Imaging and Pathology, KU Leuven, Belgium; Department of Radiology (S.S.), University Hospitals Leuven, Belgium; Department of Geriatric Psychiatry (M.V.), University Psychiatric Centre, KU Leuven, Belgium; Department of Pharmaceutical and Pharmacological Sciences (G.B.), KU Leuven, Belgium; and Division of Nuclear Medicine (K.V.L.), University Hospitals Leuven, Belgium
| | - Robin Lemmens
- From the Department of Neurosciences (L.M., S.S., M.V., R.L.), Leuven Brain Institute, Belgium; VIB, Center for Brain & Disease Research (L.M., R.L), Laboratory of Neurobiology, Belgium; Department of Neurology (L.M., R.L.), University Hospitals Leuven, Belgium; Department of Rehabilitation Sciences (L.T., G.V.), KU Leuven, Belgium; Nuclear Medicine and Molecular Imaging (N.M., M.K., K.V.L.), Department of Imaging and Pathology, KU Leuven, Belgium; Translational MRI (S.S.), Department of Imaging and Pathology, KU Leuven, Belgium; Department of Radiology (S.S.), University Hospitals Leuven, Belgium; Department of Geriatric Psychiatry (M.V.), University Psychiatric Centre, KU Leuven, Belgium; Department of Pharmaceutical and Pharmacological Sciences (G.B.), KU Leuven, Belgium; and Division of Nuclear Medicine (K.V.L.), University Hospitals Leuven, Belgium
| |
Collapse
|
3
|
Michiels L, Thijs L, Mertens N, Coremans M, Vandenbulcke M, Verheyden G, Koole M, Van Laere K, Lemmens R. Longitudinal Synaptic Density PET with 11 C-UCB-J 6 Months After Ischemic Stroke. Ann Neurol 2022; 93:911-921. [PMID: 36585914 DOI: 10.1002/ana.26593] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2022] [Revised: 11/30/2022] [Accepted: 12/28/2022] [Indexed: 01/01/2023]
Abstract
OBJECTIVE The purpose of this study was to explore longitudinal changes in synaptic density after ischemic stroke in vivo with synaptic vesicle protein 2A (SV2A) positron emission tomography (PET). METHODS We recruited patients with an ischemic stroke to undergo 11 C-UCB-J PET/MR within the first month and 6 months after the stroke. We investigated longitudinal changes of partial volume corrected 11 C-UCB-J standardized uptake value ratio (SUVR; relative to centrum semiovale) within the ischemic lesion, peri-ischemic area and unaffected ipsilesional and contralesional grey matter. We also explored crossed cerebellar diaschisis at 6 months. Additionally, we defined brain regions potentially influencing upper limb motor recovery after stroke and studied 11 C-UCB-J SUVR evolution in comparison to baseline. RESULTS In 13 patients (age = 67 ± 15 years) we observed decreasing 11 C-UCB-J SUVR in the ischemic lesion (ΔSUVR = -1.0, p = 0.001) and peri-ischemic area (ΔSUVR = -0.31, p = 0.02) at 6 months after stroke compared to baseline. Crossed cerebellar diaschisis as measured with 11 C-UCB-J SUVR was present in 11 of 13 (85%) patients at 6 months. The 11 C-UCB-J SUVR did not augment in ipsilesional or contralesional brain regions associated with motor recovery. On the contrary, there was an overall trend of declining 11 C-UCB-J SUVR in these brain regions, reaching statistical significance only in the nonlesioned part of the ipsilesional supplementary motor area (ΔSUVR = -0.83, p = 0.046). INTERPRETATION At 6 months after stroke, synaptic density further declined in the ischemic lesion and peri-ischemic area compared to baseline. Brain regions previously demonstrated to be associated with motor recovery after stroke did not show increases in synaptic density. ANN NEUROL 2023.
Collapse
Affiliation(s)
- Laura Michiels
- Department of Neurosciences, KU Leuven, Leuven, Belgium.,Laboratory of Neurobiology, VIB, Center for Brain & Disease Research, Leuven, Belgium.,Department of Neurology, University Hospitals Leuven, Leuven, Belgium.,Leuven Brain Institute, Leuven, Belgium
| | - Liselot Thijs
- Department of Rehabilitation Sciences, KU Leuven, Leuven, Belgium
| | - Nathalie Mertens
- Nuclear Medicine and Molecular Imaging, Department of Imaging and Pathology, KU Leuven, Leuven, Belgium
| | - Marjan Coremans
- Department of Rehabilitation Sciences, KU Leuven, Leuven, Belgium
| | - Mathieu Vandenbulcke
- Department of Neurosciences, KU Leuven, Leuven, Belgium.,Leuven Brain Institute, Leuven, Belgium.,Department of Geriatric Psychiatry, University Psychiatric Centre, Leuven, Belgium
| | - Geert Verheyden
- Department of Rehabilitation Sciences, KU Leuven, Leuven, Belgium
| | - Michel Koole
- Nuclear Medicine and Molecular Imaging, Department of Imaging and Pathology, KU Leuven, Leuven, Belgium
| | - Koen Van Laere
- Leuven Brain Institute, Leuven, Belgium.,Nuclear Medicine and Molecular Imaging, Department of Imaging and Pathology, KU Leuven, Leuven, Belgium.,Department of Nuclear Medicine, University Hospitals Leuven, Leuven, Belgium
| | - Robin Lemmens
- Department of Neurosciences, KU Leuven, Leuven, Belgium.,Laboratory of Neurobiology, VIB, Center for Brain & Disease Research, Leuven, Belgium.,Department of Neurology, University Hospitals Leuven, Leuven, Belgium.,Leuven Brain Institute, Leuven, Belgium
| |
Collapse
|
4
|
Mertens N, Michiels L, Vanderlinden G, Vandenbulcke M, Lemmens R, Van Laere K, Koole M. Impact of meningeal uptake and partial volume correction techniques on [ 18F]MK-6240 binding in aMCI patients and healthy controls. J Cereb Blood Flow Metab 2022; 42:1236-1246. [PMID: 35062837 PMCID: PMC9207493 DOI: 10.1177/0271678x221076023] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
[18F]MK-6240 is a second-generation tau PET-tracer to quantify neurofibrillary tangles in-vivo. However, individually variable levels of meningeal uptake induce spill-in-effects into the cortex, complicating [18F]MK-6240 PET quantification. Group SUVR differences between age-matched HC subgroups with varying extracerebral uptake (EC-low/mixed/high), and between aMCI and each HC subgroup were assessed without and with partial volume correction (PVC). Both Müller-Gartner (MG-)PVC and region-based voxelwise (RBV-)PVC, with the latter also correcting for extracerebral spill-in-effects, were implemented. Between HC groups, where no differences are to be expected, HC EC-high showed spill-in differences compared to HC EC-low when no PVC was applied while for MG-PVC, differences were reduced and, for RBV-PVC, no statistically significant differences were observed. Between aMCI and HC, cortical SUVR differences were statistically significant, both without and with PVC, but modulated by the varying meningeal uptake in HC subgroups when no PVC was applied. After applying PVC, correlations to clinical parameters improved and effect sizes between HC and aMCI increased, independent of the HC-subgroup. Therefore, appropriate PVC with correction for extracerebral spill-in-effects is recommended to minimize the impact of varying meningeal uptake on cortical differences between HC and aMCI.
Collapse
Affiliation(s)
- Nathalie Mertens
- Nuclear Medicine and Molecular Imaging, University Hospital and KU Leuven, Leuven, Belgium
| | - Laura Michiels
- Department of Neurosciences, Experimental Neurology, KU Leuven - University of Leuven, Leuven, Belgium.,VIB, Center for Brain & Disease Research, Laboratory of Neurobiology, Leuven, Belgium.,Department of Neurology, University Hospitals Leuven, Leuven, Belgium
| | - Greet Vanderlinden
- Nuclear Medicine and Molecular Imaging, University Hospital and KU Leuven, Leuven, Belgium
| | - Mathieu Vandenbulcke
- Department of Neurosciences, Experimental Neurology, KU Leuven - University of Leuven, Leuven, Belgium.,Old-Age Psychiatry, University Hospital and KU Leuven, Leuven, Belgium
| | - Robin Lemmens
- Department of Neurosciences, Experimental Neurology, KU Leuven - University of Leuven, Leuven, Belgium.,VIB, Center for Brain & Disease Research, Laboratory of Neurobiology, Leuven, Belgium.,Department of Neurology, University Hospitals Leuven, Leuven, Belgium
| | - Koen Van Laere
- Nuclear Medicine and Molecular Imaging, University Hospital and KU Leuven, Leuven, Belgium.,Division of Nuclear Medicine, University Hospitals Leuven, Belgium
| | - Michel Koole
- Nuclear Medicine and Molecular Imaging, University Hospital and KU Leuven, Leuven, Belgium
| |
Collapse
|
5
|
Mertens N, Sunaert S, Van Laere K, Koole M. The Effect of Aging on Brain Glucose Metabolic Connectivity Revealed by [18F]FDG PET-MR and Individual Brain Networks. Front Aging Neurosci 2022; 13:798410. [PMID: 35221983 PMCID: PMC8865456 DOI: 10.3389/fnagi.2021.798410] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2021] [Accepted: 12/27/2021] [Indexed: 11/13/2022] Open
Abstract
Contrary to group-based brain connectivity analyses, the aim of this study was to construct individual brain metabolic networks to determine age-related effects on brain metabolic connectivity. Static 40–60 min [18F]FDG positron emission tomography (PET) images of 67 healthy subjects between 20 and 82 years were acquired with an integrated PET-MR system. Network nodes were defined by brain parcellation using the Schaefer atlas, while connectivity strength between two nodes was determined by comparing the distribution of PET uptake values within each node using a Kullback–Leibler divergence similarity estimation (KLSE). After constructing individual brain networks, a linear and quadratic regression analysis of metabolic connectivity strengths within- and between-networks was performed to model age-dependency. In addition, the age dependency of metrics for network integration (characteristic path length), segregation (clustering coefficient and local efficiency), and centrality (number of hubs) was assessed within the whole brain and within predefined functional subnetworks. Overall, a decrease of metabolic connectivity strength with healthy aging was found within the whole-brain network and several subnetworks except within the somatomotor, limbic, and visual network. The same decrease of metabolic connectivity was found between several networks across the whole-brain network and the functional subnetworks. In terms of network topology, a less integrated and less segregated network was observed with aging, while the distribution and the number of hubs did not change with aging, suggesting that brain metabolic networks are not reorganized during the adult lifespan. In conclusion, using an individual brain metabolic network approach, a decrease in metabolic connectivity strength was observed with healthy aging, both within the whole brain and within several predefined networks. These findings can be used in a diagnostic setting to differentiate between age-related changes in brain metabolic connectivity strength and changes caused by early development of neurodegeneration.
Collapse
Affiliation(s)
- Nathalie Mertens
- Nuclear Medicine and Molecular Imaging, Department of Imaging and Pathology, KU Leuven, Leuven, Belgium
- *Correspondence: Nathalie Mertens,
| | - Stefan Sunaert
- Translational MRI, Department of Imaging and Pathology, KU Leuven, Leuven, Belgium
- Department of Radiology, University Hospitals Leuven, Leuven, Belgium
| | - Koen Van Laere
- Nuclear Medicine and Molecular Imaging, Department of Imaging and Pathology, KU Leuven, Leuven, Belgium
- Division of Nuclear Medicine, University Hospitals Leuven, Leuven, Belgium
| | - Michel Koole
- Nuclear Medicine and Molecular Imaging, Department of Imaging and Pathology, KU Leuven, Leuven, Belgium
| |
Collapse
|
6
|
Michiels L, Mertens N, Thijs L, Radwan A, Sunaert S, Vandenbulcke M, Verheyden G, Koole M, Van Laere K, Lemmens R. Changes in synaptic density in the subacute phase after ischemic stroke: A 11C-UCB-J PET/MR study. J Cereb Blood Flow Metab 2022; 42:303-314. [PMID: 34550834 PMCID: PMC9122519 DOI: 10.1177/0271678x211047759] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Functional alterations after ischemic stroke have been described with Magnetic Resonance Imaging (MRI) and perfusion Positron Emission Tomography (PET), but no data on in vivo synaptic changes exist. Recently, imaging of synaptic density became available by targeting synaptic vesicle protein 2 A, a protein ubiquitously expressed in all presynaptic nerve terminals. We hypothesized that in subacute ischemic stroke loss of synaptic density can be evaluated with 11C-UCB-J PET in the ischemic tissue and that alterations in synaptic density can be present in brain regions beyond the ischemic core. We recruited ischemic stroke patients to undergo 11C-UCB-J PET/MR imaging 21 ± 8 days after stroke onset to investigate regional 11C-UCB-J SUVR (standardized uptake value ratio). There was a decrease (but residual signal) of 11C-UCB-J SUVR within the lesion of 16 stroke patients compared to 40 healthy controls (ratiolesion/controls = 0.67 ± 0.28, p = 0.00023). Moreover, 11C-UCB-J SUVR was lower in the non-lesioned tissue of the affected hemisphere compared to the unaffected hemisphere (ΔSUVR = -0.17, p = 0.0035). The contralesional cerebellar hemisphere showed a lower 11C-UCB-J SUVR compared to the ipsilesional cerebellar hemisphere (ΔSUVR = -0.14, p = 0.0048). In 8 out of 16 patients, the asymmetry index suggested crossed cerebellar diaschisis. Future research is required to longitudinally study these changes in synaptic density and their association with outcome.
Collapse
Affiliation(s)
- Laura Michiels
- Department of Neurosciences, KU Leuven, Leuven, Belgium.,VIB, Center for Brain & Disease Research, Laboratory of Neurobiology, Leuven, Belgium.,Department of Neurology, University Hospitals Leuven, Leuven, Belgium
| | - Nathalie Mertens
- Nuclear Medicine and Molecular Imaging, 26657KU Leuven, Department of Imaging and Pathology, KU Leuven, Leuven, Belgium
| | - Liselot Thijs
- Department of Rehabilitation Sciences, 26657KU Leuven, KU Leuven, Leuven, Belgium
| | - Ahmed Radwan
- Translational MRI, 26657KU Leuven, Department of Imaging and Pathology, KU Leuven, Leuven, Belgium
| | - Stefan Sunaert
- Translational MRI, 26657KU Leuven, Department of Imaging and Pathology, KU Leuven, Leuven, Belgium.,Department of Radiology, University Hospitals Leuven, Leuven, Belgium
| | - Mathieu Vandenbulcke
- VIB, Center for Brain & Disease Research, Laboratory of Neurobiology, Leuven, Belgium.,Department of Geriatric Psychiatry, University Psychiatric Centre, KU Leuven, Leuven, Belgium
| | - Geert Verheyden
- Department of Rehabilitation Sciences, 26657KU Leuven, KU Leuven, Leuven, Belgium
| | - Michel Koole
- Nuclear Medicine and Molecular Imaging, 26657KU Leuven, Department of Imaging and Pathology, KU Leuven, Leuven, Belgium
| | - Koen Van Laere
- Nuclear Medicine and Molecular Imaging, 26657KU Leuven, Department of Imaging and Pathology, KU Leuven, Leuven, Belgium.,Division of Nuclear Medicine, University Hospitals Leuven, Leuven, Belgium
| | - Robin Lemmens
- Department of Neurosciences, KU Leuven, Leuven, Belgium.,VIB, Center for Brain & Disease Research, Laboratory of Neurobiology, Leuven, Belgium.,Department of Neurology, University Hospitals Leuven, Leuven, Belgium
| |
Collapse
|
7
|
Mertens N, Schmidt ME, Hijzen A, Van Weehaeghe D, Ravenstijn P, Depre M, de Hoon J, Van Laere K, Koole M. Minimally invasive quantification of cerebral P2X7R occupancy using dynamic [ 18F]JNJ-64413739 PET and MRA-driven image derived input function. Sci Rep 2021; 11:16172. [PMID: 34373571 PMCID: PMC8352986 DOI: 10.1038/s41598-021-95715-y] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2021] [Accepted: 07/29/2021] [Indexed: 01/21/2023] Open
Abstract
[18F]JNJ-64413739 has been evaluated as PET-ligand for in vivo quantification of purinergic receptor subtype 7 receptor (P2X7R) using Logan graphical analysis with a metabolite-corrected arterial plasma input function. In the context of a P2X7R PET dose occupancy study, we evaluated a minimally invasive approach by limiting arterial sampling to baseline conditions. Meanwhile, post dose distribution volumes (VT) under blocking conditions were estimated by combining baseline blood to plasma ratios and metabolite fractions with an MR angiography driven image derived input function (IDIF). Regional postdose VT,IDIF values were compared with corresponding VT,AIF estimates using a arterial input function (AIF), in terms of absolute values, test–retest reliability and receptor occupancy. Compared to an invasive AIF approach, postdose VT,IDIF values and corresponding receptor occupancies showed only limited bias (Bland–Altman analysis: 0.06 ± 0.27 and 3.1% ± 6.4%) while demonstrating a high correlation (Spearman ρ = 0.78 and ρ = 0.98 respectively). In terms of test–retest reliability, regional intraclass correlation coefficients were 0.98 ± 0.02 for VT,IDIF compared to 0.97 ± 0.01 for VT,AIF. These results confirmed that a postdose IDIF, guided by MR angiography and using baseline blood and metabolite data, can be considered for accurate [18F]JNJ-64413739 PET quantification in a repeated PET study design, thus avoiding multiple invasive arterial sampling and increasing dosing flexibility.
Collapse
Affiliation(s)
- Nathalie Mertens
- Nuclear Medicine and Molecular Imaging, Department of Imaging and Pathology, University Hospital and KU Leuven, Herestraat 49, 3000, Leuven, Belgium.
| | | | - Anja Hijzen
- Janssen Research and Development, Beerse, Belgium
| | - Donatienne Van Weehaeghe
- Nuclear Medicine and Molecular Imaging, Department of Imaging and Pathology, University Hospital and KU Leuven, Herestraat 49, 3000, Leuven, Belgium
| | | | - Marleen Depre
- Center for Clinical Pharmacology, University Hospital and KU Leuven, Leuven, Belgium
| | - Jan de Hoon
- Center for Clinical Pharmacology, University Hospital and KU Leuven, Leuven, Belgium
| | - Koen Van Laere
- Nuclear Medicine and Molecular Imaging, Department of Imaging and Pathology, University Hospital and KU Leuven, Herestraat 49, 3000, Leuven, Belgium
| | - Michel Koole
- Nuclear Medicine and Molecular Imaging, Department of Imaging and Pathology, University Hospital and KU Leuven, Herestraat 49, 3000, Leuven, Belgium
| |
Collapse
|
8
|
De Vocht J, Blommaert J, Devrome M, Radwan A, Van Weehaeghe D, De Schaepdryver M, Ceccarini J, Rezaei A, Schramm G, van Aalst J, Chiò A, Pagani M, Stam D, Van Esch H, Lamaire N, Verhaegen M, Mertens N, Poesen K, van den Berg LH, van Es MA, Vandenberghe R, Vandenbulcke M, Van den Stock J, Koole M, Dupont P, Van Laere K, Van Damme P. Use of Multimodal Imaging and Clinical Biomarkers in Presymptomatic Carriers of C9orf72 Repeat Expansion. JAMA Neurol 2021; 77:1008-1017. [PMID: 32421156 PMCID: PMC7417970 DOI: 10.1001/jamaneurol.2020.1087] [Citation(s) in RCA: 39] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Question Can metabolic brain changes be detected in presymptomatic individuals who are carriers of a hexanucleotide repeat expansion in the C9orf72 gene (preSxC9) using time-of-flight fluorine 18–labeled fluorodeoxyglucose positron emission tomographic imaging and magnetic resonance imaging, and what is the association between the mutation and clinical and fluid biomarkers of amyotrophic lateral sclerosis and frontotemporal dementia? Findings In a case-control study including 17 preSxC9 participants and 25 healthy controls, fluorine 18–labeled fluorodeoxyglucose positron emission tomographic imaging noted significant clusters of relative hypometabolism in frontotemporal regions, the insular cortices, basal ganglia, and thalami in the preSxC9 participants. Use of this strategy allowed detection of changes at an individual level. Meaning Glucose metabolic changes appear to occur early in the sequence of events leading to manifest amyotrophic lateral sclerosis and frontotemporal dementia. Fluorine 18–labeled fluorodeoxyglucose positron emission tomographic imaging may provide a sensitive biomarker of a presymptomatic phase of disease. Importance During a time with the potential for novel treatment strategies, early detection of disease manifestations at an individual level in presymptomatic carriers of a hexanucleotide repeat expansion in the C9orf72 gene (preSxC9) is becoming increasingly relevant. Objectives To evaluate changes in glucose metabolism before symptom onset of amyotrophic lateral sclerosis or frontotemporal dementia in preSxC9 using simultaneous fluorine 18–labeled fluorodeoxyglucose ([18F]FDG positron emission tomographic (PET) and magnetic resonance imaging as well as the mutation’s association with clinical and fluid biomarkers. Design, Setting, and Participants A prospective, case-control study enrolled 46 participants from November 30, 2015, until December 11, 2018. The study was conducted at the neuromuscular reference center of the University Hospitals Leuven, Leuven, Belgium. Main Outcomes and Measures Neuroimaging data were spatially normalized and analyzed at the voxel level at a height threshold of P < .001, cluster-level familywise error–corrected threshold of P < .05, and statistical significance was set at P < .05 for the volume-of-interest level analysis, using Benjamini-Hochberg correction for multiple correction. W-score maps were computed using the individuals serving as controls as a reference to quantify the degree of [18F]FDG PET abnormality. The threshold for abnormality on the W-score maps was designated as an absolute W-score greater than or equal to 1.96. Neurofilament levels and performance on cognitive and neurologic examinations were determined. All hypothesis tests were 1-sided. Results Of the 42 included participants, there were 17 with the preSxC9 mutation (12 women [71%]; mean [SD] age, 51 [9] years) and 25 healthy controls (12 women [48%]; mean [SD] age, 47 [10] years). Compared with control participants, significant clusters of relative hypometabolism were found in frontotemporal regions, basal ganglia, and thalami of preSxC9 participants and relative hypermetabolism in the peri-Rolandic region, superior frontal gyrus, and precuneus cortex. W-score frequency maps revealed reduced glucose metabolism with local maxima in the insular cortices, central opercular cortex, and thalami in up to 82% of preSxC9 participants and increased glucose metabolism in the precentral gyrus and precuneus cortex in up to 71% of preSxC9 participants. Other findings in the preSxC9 group were upper motor neuron involvement in 10 participants (59%), cognitive abnormalities in 5 participants (29%), and elevated neurofilament levels in 3 of 16 individuals (19%) who underwent lumbar puncture. Conclusions and Relevance The results suggest that [18F]FDG PET can identify glucose metabolic changes in preSxC9 at an individual level, preceding significantly elevated neurofilament levels and onset of symptoms.
Collapse
Affiliation(s)
- Joke De Vocht
- KU Leuven, Department of Neurosciences, Experimental Neurology, B-3000 Leuven, Belgium.,KU Leuven, University Hospitals Leuven, University Psychiatric Center, Adult Psychiatry, B-3000 Leuven, Belgium.,University Hospitals Leuven, Department of Neurology, B-3000 Leuven, Belgium.,VIB - Center of Brain & Disease Research, Laboratory of Neurobiology, B-3000 Leuven, Belgium
| | | | - Martijn Devrome
- KU Leuven, University Hospitals Leuven, Department of Imaging and Pathology, Division of Nuclear Medicine, B-3000 Leuven, Belgium
| | - Ahmed Radwan
- KU Leuven, Department of Imaging and Pathology, Translational MRI, B-3000 Leuven, Belgium
| | - Donatienne Van Weehaeghe
- KU Leuven, University Hospitals Leuven, Department of Imaging and Pathology, Division of Nuclear Medicine, B-3000 Leuven, Belgium
| | - Maxim De Schaepdryver
- KU Leuven, Department of Neurosciences, Laboratory for Molecular Neurobiomarker Research, B-3000 Leuven, Belgium
| | - Jenny Ceccarini
- KU Leuven, University Hospitals Leuven, Department of Imaging and Pathology, Division of Nuclear Medicine, B-3000 Leuven, Belgium
| | - Ahmadreza Rezaei
- KU Leuven, University Hospitals Leuven, Department of Imaging and Pathology, Division of Nuclear Medicine, B-3000 Leuven, Belgium
| | - Georg Schramm
- KU Leuven, University Hospitals Leuven, Department of Imaging and Pathology, Division of Nuclear Medicine, B-3000 Leuven, Belgium
| | - June van Aalst
- KU Leuven, University Hospitals Leuven, Department of Imaging and Pathology, Division of Nuclear Medicine, B-3000 Leuven, Belgium
| | - Adriano Chiò
- ALS Center, Rita Levi Montalcini Department of Neuroscience, University of Turin, Turin, Italy
| | - Marco Pagani
- Institute of Cognitive Sciences and Technologies, CNR, Rome, Italy.,Medical Radiation Physics and Nuclear Medicine, Karolinska University Hospital, Stockholm, Sweden
| | - Daphne Stam
- KU Leuven, Leuven Brain Institute, Laboratory for Translational Neuropsychiatry, B-3000 Leuven, Belgium
| | - Hilde Van Esch
- University Hospitals Leuven, Center for Human Genetics, B-3000 Leuven, Belgium
| | - Nikita Lamaire
- University Hospitals Leuven, Department of Neurology, B-3000 Leuven, Belgium
| | - Marianne Verhaegen
- KU Leuven, University Hospitals Leuven, University Psychiatric Center, Adult Psychiatry, B-3000 Leuven, Belgium
| | - Nathalie Mertens
- KU Leuven, University Hospitals Leuven, Department of Imaging and Pathology, Division of Nuclear Medicine, B-3000 Leuven, Belgium
| | - Koen Poesen
- KU Leuven, Department of Neurosciences, Laboratory for Molecular Neurobiomarker Research, B-3000 Leuven, Belgium
| | - Leonard H van den Berg
- Brain Center Rudolf Magnus, Department of Neurology, University Medical Center Utrecht, Utrecht, the Netherlands
| | - Michael A van Es
- Brain Center Rudolf Magnus, Department of Neurology, University Medical Center Utrecht, Utrecht, the Netherlands
| | - Rik Vandenberghe
- University Hospitals Leuven, Department of Neurology, B-3000 Leuven, Belgium.,KU Leuven, Department of Neurosciences, Laboratory for Cognitive Neurology, B-3000 Leuven, Belgium
| | - Mathieu Vandenbulcke
- KU Leuven, Leuven Brain Institute, Laboratory for Translational Neuropsychiatry, B-3000 Leuven, Belgium.,KU Leuven, University Psychiatric Center, Geriatric Psychiatry, B-3000 Leuven, Belgium
| | - Jan Van den Stock
- KU Leuven, Leuven Brain Institute, Laboratory for Translational Neuropsychiatry, B-3000 Leuven, Belgium.,KU Leuven, University Psychiatric Center, Geriatric Psychiatry, B-3000 Leuven, Belgium
| | - Michel Koole
- KU Leuven, University Hospitals Leuven, Department of Imaging and Pathology, Division of Nuclear Medicine, B-3000 Leuven, Belgium
| | - Patrick Dupont
- KU Leuven, Department of Neurosciences, Laboratory for Cognitive Neurology, B-3000 Leuven, Belgium
| | - Koen Van Laere
- KU Leuven, University Hospitals Leuven, Department of Imaging and Pathology, Division of Nuclear Medicine, B-3000 Leuven, Belgium
| | - Philip Van Damme
- KU Leuven, Department of Neurosciences, Experimental Neurology, B-3000 Leuven, Belgium.,University Hospitals Leuven, Department of Neurology, B-3000 Leuven, Belgium.,VIB - Center of Brain & Disease Research, Laboratory of Neurobiology, B-3000 Leuven, Belgium
| |
Collapse
|
9
|
Fransen K, Boen F, Vansteenkiste M, Mertens N, Vande Broek G. The power of competence support: The impact of coaches and athlete leaders on intrinsic motivation and performance. Scand J Med Sci Sports 2017; 28:725-745. [DOI: 10.1111/sms.12950] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/17/2017] [Indexed: 11/26/2022]
Affiliation(s)
- K. Fransen
- Department of Kinesiology; KU Leuven; Leuven Belgium
| | - F. Boen
- Department of Kinesiology; KU Leuven; Leuven Belgium
| | | | - N. Mertens
- Department of Kinesiology; KU Leuven; Leuven Belgium
| | | |
Collapse
|
10
|
Gerbershagen H, Dagtekin O, Mertens N, Isenberg J, Sabatowski R, Petzke F. 531 PREVALENCE AND SEVERITY OF CHRONIC PAIN AFTER PELVIC RING FRACTURE. Eur J Pain 2009. [DOI: 10.1016/s1090-3801(09)60534-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Affiliation(s)
- H.J. Gerbershagen
- Department of Anesthesiology, University Medical Center Utrecht, Utrecht, Netherlands
| | - O. Dagtekin
- Department of Anesthesiology, University of Cologne, Cologne, Germany
| | - N. Mertens
- Department of Anesthesiology, University of Cologne, Cologne, Germany
| | - J. Isenberg
- Department of Traumatology and Orthopedics, Hospital Nordstad, Hannover, Germany
| | - R. Sabatowski
- Department of Anesthesiology, Technical University of Dresden, Dresden, Germany
| | - F. Petzke
- Department of Anesthesiology, University of Cologne, Cologne, Germany
| |
Collapse
|
11
|
Tinke A, Carnicer A, Govoreanu R, Scheltjens G, Lauwerysen L, Mertens N, Vanhoutte K, Brewster M. Particle shape and orientation in laser diffraction and static image analysis size distribution analysis of micrometer sized rectangular particles. POWDER TECHNOL 2008. [DOI: 10.1016/j.powtec.2007.11.017] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
|
12
|
Van de Wiele C, Revets H, Mertens N. Radioimmunoimaging. Advances and prospects. Q J Nucl Med Mol Imaging 2004; 48:317-25. [PMID: 15640795] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/01/2023]
Abstract
The advent of biotechnology has made it possible to overcome the undesired host antiglobulin response evidenced following the injection of rodent antibodies for radioimmunoimaging; initially through the construction of chimeric and CDR-grafted antibodies and more recently through the derivation of completely human antibodies. Available platforms for derivation of completely human antibodies include phage- and ribosome-display techniques and transgenic mice that are deleted in their own antibody genes and reconstituted with large parts of the genes encoding for human antibodies. Additionally, biotechnology has made it possible to tailor affinity, respectively through CDR-walking or chain schuffling, and avidity, respectively through manifold engineering, of antibodies and derivatives. More recent developments include the development of highly stable single domain binders based on the use of a conserved framework region and a highly variable antigen-binding site, using other proteins or molecules that are smaller in size and easier to manufacture than antibodies. Finally, novel technologies have been and are being developed optimizing the concept of pretargeting.
Collapse
Affiliation(s)
- C Van de Wiele
- Department of Nuclear Medicine, University Hospital, Ghent, Belgium.
| | | | | |
Collapse
|
13
|
De Wilde G, Mertens N, Boone E, De Vreese B, Van Beeumen J, Fiers W, Haegeman G. Expression in Escherichia coli of the death domain of the human p55 tumor necrosis factor receptor. Protein Expr Purif 2001; 23:226-32. [PMID: 11676596 DOI: 10.1006/prep.2001.1499] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The p55 tumor necrosis factor receptor (TNF-RI) is the main receptor by which TNF exerts its effects. The signaling capacity largely depends on the presence of an intact C-terminal protein-protein interaction domain, a so-called death domain (DD). Here we report the expression and purification of the human TNF-RI DD as a fusion with the Escherichia coli thioredoxin A (TRX) protein. When expressed under control of the bacteriophage T7 promoter, TRX-DD accumulates as a soluble protein in the cytoplasm of E. coli. The TRX-DD protein was released from the cells into the periplasmic fraction after osmotic shock. Due to self-association of the DD, a large part of the material appeared as multimers; it could be removed by selective precipitation and a combination of ion-exchange and size-exclusion chromatography. This purification protocol yielded 30 mg of purified, monomeric protein from 1 liter of shake-flask culture. The purified TRX-DD was found to be functional as it still bound to the TNF-RI-associated DD protein and the intracellular part of TNF-RI. We conclude that TRX-DD is correctly folded and can be used for further structure/function analysis.
Collapse
MESH Headings
- Antigens, CD/chemistry
- Antigens, CD/genetics
- Antigens, CD/isolation & purification
- Cloning, Molecular
- Escherichia coli
- Humans
- Protein Structure, Tertiary
- Receptors, Tumor Necrosis Factor/chemistry
- Receptors, Tumor Necrosis Factor/genetics
- Receptors, Tumor Necrosis Factor/isolation & purification
- Receptors, Tumor Necrosis Factor, Type I
- Recombinant Fusion Proteins/chemistry
- Recombinant Fusion Proteins/genetics
- Recombinant Fusion Proteins/isolation & purification
- Thioredoxins/genetics
Collapse
Affiliation(s)
- G De Wilde
- Department of Molecular Biology, Gent University and Flanders Interuniversity Institute for Biotechnology, 9000 Gent, Belgium
| | | | | | | | | | | | | |
Collapse
|
14
|
Schoonjans R, Willems A, Schoonooghe S, Leoen J, Grooten J, Mertens N. A new model for intermediate molecular weight recombinant bispecific and trispecific antibodies by efficient heterodimerization of single chain variable domains through fusion to a Fab-chain. Biomol Eng 2001; 17:193-202. [PMID: 11337278 DOI: 10.1016/s1389-0344(01)00066-1] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Due to their specificity and versatility in use, bispecific antibodies (BsAbs) are promising therapeutic tools in tomorrow's medicine, provided sufficient BsAb can be produced. Expression systems favoring efficient heterodimerization of intermediate-sized bispecific antibodies will significantly improve existing production methods. Recombinant BsAb can be made by fusing single chain variable fragments (scFv) to a heterodimerization domain. We compare the efficiency of the isolated CL and CH1 constant domains with complete Fab chains to drive heterodimerization of BsAbs in mammalian cells. We found that the isolated CL:CH1 domain interaction was inefficient for secretion of heterodimers. However, when the complete Fab chains were used, secretion of a heterodimerized bispecific antibody was successful. Since the Fab chain encodes a binding specificity on its own, bispecific (BsAb) or trispecific (TsAb) antibodies can be made by C-terminal fusion of scFv molecules to the L or Fd Fab chains. This gave rise to disulphide stabilized Fab-scFv BsAb (Bibody)or Fab-(scFv)2 TsAb (Tribody) of intermediate molecular size. Heterodimerization of the L and Fd-containing fusion proteins was very efficient, and up to 90% of all secreted antibody fragments was in the desired heterodimerized format. All building blocks remained functional in the fusion product, and the bispecific character of the molecules as well as the immunological functionality was demonstrated.
Collapse
Affiliation(s)
- R Schoonjans
- Department of Molecular Biology, Molecular Immunology Unit, Flanders Interuniversity, Institute for Biotechnology (VIB), University of Ghent, K.L. Ledeganckstraat 35, B-9000 Ghent, Belgium
| | | | | | | | | | | |
Collapse
|
15
|
Abstract
Bispecific antibodies (BsAb) are promising therapeutic tools in tomorrow's medicine. Expression systems favoring efficient heterodimerization of intermediate-sized bispecific antibodies will significantly improve existing production methods. By C-terminal fusion of scFv molecules to the Fd- and the L-chains efficient heterodimerization in mammalian cells was obtained and a novel intermediate sized, disulfide stabilized BsAb could be efficiently produced. This type of antibody derivative easily allows for the production of trispecific antibodies, BsAb with bivalent binding for one antigen, or immunoconjugates.
Collapse
Affiliation(s)
- R Schoonjans
- Department of Molecular Biology, University of Gent, Belgium
| | | | | | | |
Collapse
|
16
|
Schoonjans R, Willems A, Schoonooghe S, Fiers W, Grooten J, Mertens N. Fab chains as an efficient heterodimerization scaffold for the production of recombinant bispecific and trispecific antibody derivatives. J Immunol 2000; 165:7050-7. [PMID: 11120833 DOI: 10.4049/jimmunol.165.12.7050] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Due to their multispecificity and versatility, bispecific Abs (BsAbs) are promising therapeutic tools in tomorrow's medicine. Especially intermediate-sized BsAbs that combine body retention with tissue penetration are valuable for therapy but necessitate expression systems that favor heterodimerization of the binding sites for large-scale application. To identify heterodimerization domains to which single-chain variable fragments (scFv) can be fused, we compared the efficiency of heterodimerization of CL and CH1 constant domains with complete L and Fd chains in mammalian cells. We found that the isolated CL:CH1 domain interaction was inefficient for secretion of heterodimers. However, when the complete L and Fd chains were used, secretion of L:Fd heterodimers was highly successful. Because these Fab chains contribute a binding moiety, C-terminal fusion of a scFv molecule to the L and/or Fd chains generated BsAbs or trispecific Abs (TsAbs) of intermediate size (75-100 kDa). These disulfide-stabilized bispecific Fab-scFv ("bibody") and trispecific Fab-(scFv)(2) ("tribody") heterodimers represent up to 90% of all secreted Ab fragments in the mammalian expression system and possess fully functional binding moieties. Furthermore, both molecules recruit and activate T cells in a tumor cell-dependent way, whereby the trispecific derivative can exert this activity to two different tumor cells. Thus we propose the use of the disulfide-stabilized L:Fd heterodimer as an efficient platform for production of intermediate-sized BsAbs and TsAbs in mammalian expression systems.
Collapse
MESH Headings
- Adjuvants, Immunologic/chemical synthesis
- Adjuvants, Immunologic/genetics
- Adjuvants, Immunologic/metabolism
- Adjuvants, Immunologic/pharmacology
- Animals
- Antibodies, Bispecific/biosynthesis
- Antibodies, Bispecific/genetics
- Antibodies, Bispecific/pharmacology
- Binding Sites, Antibody/genetics
- Cell Line
- Cytotoxicity, Immunologic/genetics
- Dimerization
- Drug Stability
- Humans
- Immunoglobulin Constant Regions/genetics
- Immunoglobulin Constant Regions/metabolism
- Immunoglobulin Fab Fragments/genetics
- Immunoglobulin Fab Fragments/metabolism
- Immunoglobulin Variable Region/genetics
- Immunoglobulin Variable Region/metabolism
- Lymphocyte Activation/genetics
- Mice
- Mice, Inbred BALB C
- Mice, Inbred C3H
- Protein Structure, Tertiary/genetics
- Recombinant Fusion Proteins/biosynthesis
- Recombinant Fusion Proteins/immunology
- Recombinant Fusion Proteins/pharmacology
- T-Lymphocytes/immunology
- Tumor Cells, Cultured
Collapse
Affiliation(s)
- R Schoonjans
- Molecular Immunology Unit, Department of Molecular Biology, Flanders Interuniversity Institute for Biotechnology, Ghent University, Ghent, Belgium
| | | | | | | | | | | |
Collapse
|
17
|
Abstract
The mRNA encoding the major capsid protein of phage T7 (T7g10) is highly expressed in Escherichia coli. In common with other highly expressed T7 genes, the 5' end of this mRNA contains a stem-loop structure, while transcription termination at the phage T7 T phi terminator generates a stable 3'-end stem-loop structure. We assessed the influence of these structures on the expression level of T7g10 and on the functional stability of the mRNA. Each one of the 5'- or 3'-hairpin structures was sufficient to increase the functional stability of the T7g10 mRNA more than twofold. A duplication of the 3' T phi-terminator slightly increased the mRNA stability further. Also, differences in the observed functional half-life could be correlated with the expression level of the T7g10 derivatives when these were partially induced. Our data suggest that mRNA stabilization by a 5' stem-loop structure can occur even in the absence of a stem-loop structure that protects RNA against 3' exonucleases.
Collapse
Affiliation(s)
- N Mertens
- Department of Molecular Biology, Flanders interuniversity Institute of Biotechnology (VIB), University of Gent, Belgium
| | | | | |
Collapse
|
18
|
Mertens N, Remaut E, Fiers W. Versatile, multi-featured plasmids for high-level expression of heterologous genes in Escherichia coli: overproduction of human and murine cytokines. Gene X 1995; 164:9-15. [PMID: 7590329 DOI: 10.1016/0378-1119(95)00505-z] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
We describe the construction, expression characteristics and some applications of a versatile dual-promoter expression plasmid for heterologous gene expression in Escherichia coli which contains both lambda pL and PT7 promoters. Furthermore, the plasmid is optimized to allow the expression of mature coding sequences without compromising the strength of the highly efficient PT7 or of the T7g10 ribosome-binding site. The effect of the the naturally occurring RNA loops at both the 5' and 3' ends of the T7g10 mRNA on expression was also examined. A double T7 RNA polymerase transcription terminator was inserted to ensure more reliable transcription termination and a higher expression level of the preceding gene. Further improvements involve a clockwise orientation of the promoters to minimize read-through transcription from plasmid promoters, a largely extended multiple cloning site, an antisense phage T3 promoter and a phage f1-derived, single-stranded replication origin. Variants of this plasmid allow for the production of fusion proteins with part of T7g10, a hexahistidine peptide and an enterokinase recognition site. The potential of these expression vectors is demonstrated by comparing the expression levels of a number of mammalian cytokines (human tumor necrosis factor, human immune interferon, human and murine interleukins 2, murine interleukin 4 and murine fibroblast interferon), using these expression plasmids.
Collapse
Affiliation(s)
- N Mertens
- Laboratory of Molecular Biology, University of Gent, Belgium
| | | | | |
Collapse
|
19
|
Zhang J, Vandevyver C, Stinissen P, Mertens N, van den Berg-Loonen E, Raus J. Activation and clonal expansion of human myelin basic protein-reactive T cells by bacterial superantigens. J Autoimmun 1995; 8:615-32. [PMID: 7492354 DOI: 10.1016/0896-8411(95)90012-8] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Autoreactive T cells specific for myelin basic protein (MBP) are part of the normal T cell repertoire and are present both in patients with multiple sclerosis (MS) and healthy individuals. There is evidence suggesting in vivo activation and persistent clonal expansion of MBP-reactive T cells in MS. This study was undertaken to investigate the potential role of bacterial superantigens (SA) in the activation of MBP-reactive T cells. Twenty-seven MBP-reactive T cell clones generated from 10 MS patients and one normal individual were examined for reactivity to SA, in association with their T cell receptor V beta gene usage. The majority of the clones responded to at least one of the SA tested, staphylococcal enterotoxins (SEA and SEB) and toxic shock syndrome toxin-1 (TSST-1). The clones reactive to SEA and SEB expressed various V beta genes while T cell reactivity to TSST-1 correlated with the V beta 2 expression. Furthermore, circulating MBP-reactive T cells could be expanded from lymphocyte cultures primarily exposed to respective SA in more than 50% of MS patients and normal individuals tested. However, activation and expansion of circulating MBP-reactive T cells by SA was not directly associated with the disease. This study lends support to the potential role of SA in the activation of MBP-reactive T cells and suggests that an altered regulatory mechanism may account for further expansion and persistence of MBP-reactive T cells in MS.
Collapse
Affiliation(s)
- J Zhang
- Multiple Sclerosis Research and Immunology Unit, Dr. Willems Instituut, Diepenbeek, Belgium
| | | | | | | | | | | |
Collapse
|
20
|
Vandevyver C, Mertens N, van den Elsen P, Medaer R, Raus J, Zhang J. Clonal expansion of myelin basic protein-reactive T cells in patients with multiple sclerosis: restricted T cell receptor V gene rearrangements and CDR3 sequence. Eur J Immunol 1995; 25:958-68. [PMID: 7537675 DOI: 10.1002/eji.1830250416] [Citation(s) in RCA: 73] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Myelin basic protein (MBP)-reactive T cells are thought to play an important role in the pathogenesis of multiple sclerosis (MS). In some patients with MS, these autoreactive T cells display a limited heterogeneity in their epitope recognition and T cell receptor (TCR) variable (V) gene usage. These individual-dependent properties of MBP-reactive T cells have led to the speculation that they may represent clonal expansion in vivo in some MS patients. In the present study, 51 MBP-reactive T cell clones derived from patients with MS and healthy individuals were examined for their epitope recognition and the TCR V alpha and V beta gene rearrangements. The V gene junctional region sequences of identified alpha and beta genes were further analyzed to probe their clonal origins, as the sequences are unique for individual clones. Our data showed that 26 clones derived from nine patients with MS shared a predominant reactivity to the immunodominant regions of MBP, 84-102, 110-129 and 143-168, and used various TCR V alpha and V beta rearrangements. The V gene usage of the clones was restricted to certain V alpha V beta combination(s) in a given MS patient, but varied among different patients. The sequence analysis revealed that the clones generated from a given patient shared a limited or a single junctional region sequence pattern(s), indicating their oligoclonal or monoclonal origin(s). In contrast, 25 MBP-reactive T cell clones derived from normal individuals exhibited unfocused epitope recognition and V gene usage. Thus, the limited heterogeneity of MBP-reactive T cells in their structural and functional characteristics reflects their clonal expansion in vivo in some patients with MS.
Collapse
Affiliation(s)
- C Vandevyver
- Dr. L. Willems-Institut, Multiple Sclerosis Research and Immunology Unit, Diepenbeek, Belgium
| | | | | | | | | | | |
Collapse
|
21
|
Mertens N, Remaut E, Fiers W. Tight transcriptional control mechanism ensures stable high-level expression from T7 promoter-based expression plasmids. Biotechnology (N Y) 1995; 13:175-9. [PMID: 9634760 DOI: 10.1038/nbt0295-175] [Citation(s) in RCA: 70] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
One of the more efficient systems for high-level expression of cloned genes in Escherichia coli makes use of a phage T7 late promoter whose activity depends on a regulatable transcription unit supplying the specific T7 RNA polymerase. Using various T7 RNA polymerase/T7 promoter-based vector host systems with differential control on expression of the T7 RNA polymerase, we document that leaky expression of the latter is responsible for the frequently observed loss of the culture's ability to express genes of interest. We further show that the inability to achieve detectable expression levels can be overcome by using a tightly repressed expression system. We describe a novel and efficient control system in which basal level expression of T7 RNA polymerase is attenuated by a series of tandemly arranged transcription terminators. The plasmids also incorporate the phage lambda-derived nutL/N protein antitermination function, allowing conditional reversion of attenuation upon induction. The applicability of the system is illustrated by the strictly regulatable, high-level production of several cytokines of human and murine origin.
Collapse
Affiliation(s)
- N Mertens
- Laboratory of Molecular Biology, University of Gent, Belgium.
| | | | | |
Collapse
|
22
|
Henkel R, Stalf T, Mertens N, Miska W, Schill WB. Outer dense fibres of human spermatozoa: partial characterization and possible physiological functions. Int J Androl 1994; 17:68-73. [PMID: 8026872 DOI: 10.1111/j.1365-2605.1994.tb01222.x] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
The outer dense fibres are accessory fibres in the spermatozoon. They represent up to 30% of the protein portion in human spermatozoa and are involved in sperm progressive motility. If outer dense fibres are missing or developed poorly, spermatozoa are only locally motile. For isolation of the outer dense fibres, human spermatozoa were sonicated at 25 kHz and the flagella were separated by density gradient centrifugation in Percoll. Thereafter, membranes and fibrous sheath were dissolved under reducing conditions in the cationic detergent cetyltrimethylammonium bromide for 30, 60 and 90 min, respectively. The isolation steps were monitored by phase contrast microscopy and electron microscopy. After SDS-polyacrylamide gel electrophoresis and silver staining of isolated outer dense fibres, two protein bands at 55 and 67 kDa could be detected. By means of rhodamine B staining, no phosphorus could be detected in the outer dense fibre proteins.
Collapse
Affiliation(s)
- R Henkel
- Department of Dermatology and Andrology, Justus Liebig-University of Giessen, Germany
| | | | | | | | | |
Collapse
|
23
|
Guisez Y, Demolder J, Mertens N, Raeymaekers A, Plaetinck G, Robbens J, Vandekerckhove J, Remaut E, Fiers W. High-level expression, purification, and renaturation of recombinant murine interleukin-2 from Escherichia coli. Protein Expr Purif 1993; 4:240-6. [PMID: 8390881 DOI: 10.1006/prep.1993.1031] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
A murine interleukin-2 (mIL-2)-encoding cDNA, isolated from a stimulated EL4 mRNA library, was used to construct several expression plasmids directing synthesis of the mature protein in Escherichia coli. The expression was under control of either the PTrp or the PL promoter. Using these systems, a high-level expression of between 10 and 35% of the total cellular protein was obtained. The mIL-2 protein, present as insoluble inclusion bodies, could be solubilized in a chaotropic mixture and was partially purified by preparative gel filtration under denaturing conditions. After renaturation, the protein was further purified to homogeneity by anion-exchange chromatography. Depending on the fermentation, induction, and renaturation conditions, the yield ranged between 0.35 and 1 mg of purified mIL-2/g wet cells. The specific biological activity was about 10(7) units/mg and the endotoxin content < 4 ng/mg pure recombinant protein.
Collapse
Affiliation(s)
- Y Guisez
- Laboratory of Molecular Biology, University, Gent, Belgium
| | | | | | | | | | | | | | | | | |
Collapse
|
24
|
|
25
|
Kessler M, Mertens N, Hurault de Ligny B, Huriet C. [Acute renal failure linked to treatment with glafenine and its derivatives]. Therapie 1982; 37:455-60. [PMID: 6127819] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
|
26
|
Mertens N, Vandeputte M, Dryon L, Massart DL. [Fluorine determination in lemonades and mineral waters (author's transl)]. J Pharm Belg 1982; 37:53-8. [PMID: 7077513] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
|