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Vainio SK, Dickens AM, Matilainen M, López-Picón FR, Aarnio R, Eskola O, Solin O, Anthony DC, Rinne JO, Airas L, Haaparanta-Solin M. Dimethyl fumarate decreases short-term but not long-term inflammation in a focal EAE model of neuroinflammation. EJNMMI Res 2022; 12:6. [PMID: 35107664 PMCID: PMC8811048 DOI: 10.1186/s13550-022-00878-y] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2021] [Accepted: 12/27/2021] [Indexed: 12/16/2022] Open
Abstract
Background Dimethyl fumarate (DMF) is an oral immunomodulatory drug used in the treatment of autoimmune diseases. Here, we sought to study whether the effect of DMF can be detected using positron emission tomography (PET) targeting the 18-kDa translocator protein (TSPO) in the focal delayed-type hypersensitivity rat model of multiple sclerosis (fDTH-EAE). The rats were treated orally twice daily from lesion activation (day 0) with either vehicle (tap water with 0.08% Methocel, 200 µL; control group n = 4 (3 after week four)) or 15 mg/kg DMF (n = 4) in 0.08% aqueous Methocel (200 µL) for 8 weeks. The animals were imaged by PET using the TSPO tracer [18F]GE-180 in weeks 0, 1, 2, 4, 8, and 18 following lesion activation, and the non-displaceable binding potential (BPND) was calculated. Immunohistochemical staining for Iba1, CD4, and CD8 was performed in week 18, and in separate cohorts of animals, following 2 or 4 weeks of treatment. Results Using the fDTH-EAE model, DMF reduced the [18F]GE-180 BPND in the DMF-treated animals compared to control animals after 1 week of treatment (two-tailed unpaired t test, p = 0.031), but not in weeks 2, 4, 8, or 18 when imaged in vivo by PET. Immunostaining for Iba1 showed that DMF had no effect on the perilesional volume or the core lesion volume after 2 or 4 weeks of treatment, or at 18 weeks. However, the optical density (OD) measurements of CD4+ staining showed reduced OD in the lesions of the treated rats. Conclusions DMF reduced the microglial activation in the fDTH-EAE model after 1 week of treatment, as detected by PET imaging of the TSPO ligand [18F]GE-180. However, over an extended time course, reduced microglial activation was not observed using [18F]GE-180 or by immunohistochemistry for Iba1+ microglia/macrophages. Additionally, DMF did affect the infiltration of CD4+ and CD8+ T-lymphocytes at the fDTH-EAE lesion. Supplementary Information The online version contains supplementary material available at 10.1186/s13550-022-00878-y. In a focal rat DTH-EAE model of neuroinflammation, dimethyl fumarate decreases the uptake of TSPO PET tracer [18F]GE-180 in the short term. Long-term [18F]GE-180 follow-up did not indicate a treatment effect. Decreased neuroinflammation, CD4+ T cell infiltration, and CD8+ T cell infiltration were detected using immunohistochemistry.
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Affiliation(s)
- S K Vainio
- Turku PET Centre, Preclinical PET Imaging, Preclinical Imaging Laboratory, University of Turku, Tykistökatu 6 A, 20520, Turku, Finland. .,MediCity Research Laboratory, University of Turku, Turku, Finland.
| | - A M Dickens
- Department of Chemistry, University of Turku, Turku, Finland.,Turku Bioscience, Turku, Finland
| | - M Matilainen
- Faculty of Science and Engineering, Åbo Akademi University, Turku, Finland.,Turku PET Centre, University of Turku, Turku, Finland
| | - F R López-Picón
- Turku PET Centre, Preclinical PET Imaging, Preclinical Imaging Laboratory, University of Turku, Tykistökatu 6 A, 20520, Turku, Finland.,MediCity Research Laboratory, University of Turku, Turku, Finland
| | - R Aarnio
- MediCity Research Laboratory, University of Turku, Turku, Finland.,Turku PET Centre, University of Turku, Turku, Finland
| | - O Eskola
- Turku PET Centre, Radiopharmaceutical Chemistry Laboratory, University of Turku, Turku, Finland
| | - O Solin
- Accelerator Laboratory, Åbo Akademi University, Turku, Finland.,Turku PET Centre, Radiopharmaceutical Chemistry Laboratory, University of Turku, Turku, Finland
| | - D C Anthony
- Department of Pharmacology, University of Oxford, Oxford, UK
| | - J O Rinne
- Division of Clinical Neurosciences, Turku University Hospital, Turku, Finland.,Turku PET Centre, University of Turku, Turku, Finland
| | - L Airas
- Division of Clinical Neurosciences, Turku University Hospital, Turku, Finland.,Department of Clinical Medicine, University of Turku, Turku, Finland
| | - M Haaparanta-Solin
- Turku PET Centre, Preclinical PET Imaging, Preclinical Imaging Laboratory, University of Turku, Tykistökatu 6 A, 20520, Turku, Finland.,MediCity Research Laboratory, University of Turku, Turku, Finland
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Vainio SK, Dickens AM, Tuisku J, Eskola O, Solin O, Löyttyniemi E, Anthony DC, Rinne JO, Airas L, Haaparanta-Solin M. Cessation of anti-VLA-4 therapy in a focal rat model of multiple sclerosis causes an increase in neuroinflammation. EJNMMI Res 2019; 9:38. [PMID: 31073768 PMCID: PMC6509289 DOI: 10.1186/s13550-019-0508-7] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2019] [Accepted: 04/15/2019] [Indexed: 11/21/2022] Open
Abstract
Background Positron emission tomography (PET) can be used for in vivo evaluation of the pathology associated with multiple sclerosis. We investigated the use of longitudinal PET imaging and the 18-kDa translocator protein (TSPO) binding radioligand [18F]GE-180 to detect changes in a chronic multiple sclerosis-like focal delayed-type hypersensitivity experimental autoimmune encephalomyelitis (fDTH-EAE) rat model during and after anti-VLA-4 monoclonal antibody (mAb) treatment. Thirty days after lesion activation, fDTH-EAE rats were treated with the anti-VLA-4 mAb (n = 4) or a control mAb (n = 4; 5 mg/kg, every third day, subcutaneously) for 31 days. Animals were imaged with [18F]GE-180 on days 30, 44, 65, 86 and 142. Another group of animals (n = 4) was used for visualisation the microglia with Iba-1 at day 44 after a 2-week treatment period. Results After a 2-week treatment period on day 44, there was a declining trend (p = 0.067) in [18F]GE-180-binding in the anti-VLA-4 mAb-treated animals versus controls. However, cessation of treatment for 4 days after a 31-day treatment period increased [18F]GE-180 binding in animals treated with anti-VLA-4 mAb compared to the control group (p = 0.0003). There was no difference between the groups in TSPO binding by day 142. Conclusions These results demonstrated that cessation of anti-VLA-4 mAb treatment for 4 days caused a transient rebound increase in neuroinflammation. This highlights the usefulness of serial TSPO imaging in the fDTH-EAE model to better understand the rebound phenomenon.
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Affiliation(s)
- S K Vainio
- Turku PET Centre, Preclinical PET Imaging, University of Turku, Tykistökatu 6 A, 20520, Turku, Finland. .,MediCity Research Laboratory, University of Turku, Turku, Finland.
| | - A M Dickens
- Turku Centre for Biotechnology, University of Turku, Turku, Finland.,Department of Pharmacology, University of Oxford, Oxford, UK
| | - J Tuisku
- Turku PET Centre, Clinical Neurology, Turku University Hospital, Turku, Finland
| | - O Eskola
- Turku PET Centre, Radiopharmaceutical Chemistry Laboratory, University of Turku, Turku, Finland
| | - O Solin
- Turku PET Centre, Radiopharmaceutical Chemistry Laboratory, University of Turku, Turku, Finland.,Department of Chemistry, University of Turku, Turku, Finland.,Accelerator Laboratory, Åbo Akademi University, Turku, Finland
| | - E Löyttyniemi
- Department of Biostatistics, University of Turku, Turku, Finland
| | - D C Anthony
- Department of Pharmacology, University of Oxford, Oxford, UK
| | - J O Rinne
- Turku PET Centre, Clinical Neurology, Turku University Hospital, Turku, Finland
| | - L Airas
- Turku PET Centre, Clinical Neurology, Turku University Hospital, Turku, Finland.,Division of Clinical Neurosciences, Turku University Hospital, Turku, Finland.,Department of Clinical Medicine, University of Turku, Turku, Finland
| | - M Haaparanta-Solin
- Turku PET Centre, Preclinical PET Imaging, University of Turku, Tykistökatu 6 A, 20520, Turku, Finland.,MediCity Research Laboratory, University of Turku, Turku, Finland
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