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Gold L, Barci E, Brendel M, Orth M, Cheng J, Kirchleitner SV, Bartos LM, Pötter D, Kirchner MA, Unterrainer LM, Kaiser L, Ziegler S, Weidner L, Riemenschneider MJ, Unterrainer M, Belka C, Tonn JC, Bartenstein P, Niyazi M, von Baumgarten L, Kälin RE, Glass R, Lauber K, Albert NL, Holzgreve A. The Traumatic Inoculation Process Affects TSPO Radioligand Uptake in Experimental Orthotopic Glioblastoma. Biomedicines 2024; 12:188. [PMID: 38255293 PMCID: PMC10813339 DOI: 10.3390/biomedicines12010188] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2023] [Revised: 01/10/2024] [Accepted: 01/11/2024] [Indexed: 01/24/2024] Open
Abstract
BACKGROUND The translocator protein (TSPO) has been proven to have great potential as a target for the positron emission tomography (PET) imaging of glioblastoma. However, there is an ongoing debate about the potential various sources of the TSPO PET signal. This work investigates the impact of the inoculation-driven immune response on the PET signal in experimental orthotopic glioblastoma. METHODS Serial [18F]GE-180 and O-(2-[18F]fluoroethyl)-L-tyrosine ([18F]FET) PET scans were performed at day 7/8 and day 14/15 after the inoculation of GL261 mouse glioblastoma cells (n = 24) or saline (sham, n = 6) into the right striatum of immunocompetent C57BL/6 mice. An additional n = 25 sham mice underwent [18F]GE-180 PET and/or autoradiography (ARG) at days 7, 14, 21, 28, 35, 50 and 90 in order to monitor potential reactive processes that were solely related to the inoculation procedure. In vivo imaging results were directly compared to tissue-based analyses including ARG and immunohistochemistry. RESULTS We found that the inoculation process represents an immunogenic event, which significantly contributes to TSPO radioligand uptake. [18F]GE-180 uptake in GL261-bearing mice surpassed [18F]FET uptake both in the extent and the intensity, e.g., mean target-to-background ratio (TBRmean) in PET at day 7/8: 1.22 for [18F]GE-180 vs. 1.04 for [18F]FET, p < 0.001. Sham mice showed increased [18F]GE-180 uptake at the inoculation channel, which, however, continuously decreased over time (e.g., TBRmean in PET: 1.20 at day 7 vs. 1.09 at day 35, p = 0.04). At the inoculation channel, the percentage of TSPO/IBA1 co-staining decreased, whereas TSPO/GFAP (glial fibrillary acidic protein) co-staining increased over time (p < 0.001). CONCLUSION We identify the inoculation-driven immune response to be a relevant contributor to the PET signal and add a new aspect to consider for planning PET imaging studies in orthotopic glioblastoma models.
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Affiliation(s)
- Lukas Gold
- Department of Nuclear Medicine, LMU University Hospital, LMU Munich, Marchioninistr. 15, 81377 Munich, Germany; (L.G.)
| | - Enio Barci
- Department of Nuclear Medicine, LMU University Hospital, LMU Munich, Marchioninistr. 15, 81377 Munich, Germany; (L.G.)
- Neurosurgical Research, Department of Neurosurgery, LMU University Hospital, LMU Munich, Marchioninistr. 15, 81377 Munich, Germany
| | - Matthias Brendel
- Department of Nuclear Medicine, LMU University Hospital, LMU Munich, Marchioninistr. 15, 81377 Munich, Germany; (L.G.)
- Munich Cluster for Systems Neurology (SyNergy), LMU Munich, 81377 Munich, Germany
| | - Michael Orth
- Department of Radiation Oncology, LMU University Hospital, LMU Munich, Marchioninistr. 15, 81377 Munich, Germany
- Department of Radiation Oncology, University Hospital Tübingen, 72076 Tübingen, Germany
| | - Jiying Cheng
- Neurosurgical Research, Department of Neurosurgery, LMU University Hospital, LMU Munich, Marchioninistr. 15, 81377 Munich, Germany
| | - Sabrina V. Kirchleitner
- Department of Neurosurgery, LMU University Hospital, LMU Munich, Marchioninistr 15, 81377 Munich, Germany
| | - Laura M. Bartos
- Department of Nuclear Medicine, LMU University Hospital, LMU Munich, Marchioninistr. 15, 81377 Munich, Germany; (L.G.)
| | - Dennis Pötter
- Department of Nuclear Medicine, LMU University Hospital, LMU Munich, Marchioninistr. 15, 81377 Munich, Germany; (L.G.)
| | - Maximilian A. Kirchner
- Department of Nuclear Medicine, LMU University Hospital, LMU Munich, Marchioninistr. 15, 81377 Munich, Germany; (L.G.)
| | - Lena M. Unterrainer
- Department of Nuclear Medicine, LMU University Hospital, LMU Munich, Marchioninistr. 15, 81377 Munich, Germany; (L.G.)
| | - Lena Kaiser
- Department of Nuclear Medicine, LMU University Hospital, LMU Munich, Marchioninistr. 15, 81377 Munich, Germany; (L.G.)
| | - Sibylle Ziegler
- Department of Nuclear Medicine, LMU University Hospital, LMU Munich, Marchioninistr. 15, 81377 Munich, Germany; (L.G.)
| | - Lorraine Weidner
- Department of Neuropathology, Regensburg University Hospital, 93053 Regensburg, Germany
| | | | - Marcus Unterrainer
- Department of Nuclear Medicine, LMU University Hospital, LMU Munich, Marchioninistr. 15, 81377 Munich, Germany; (L.G.)
- DIE RADIOLOGIE, 80331 Munich, Germany
| | - Claus Belka
- Department of Radiation Oncology, LMU University Hospital, LMU Munich, Marchioninistr. 15, 81377 Munich, Germany
- German Cancer Consortium (DKTK), Partner Site Munich, 81377 Munich, Germany
- Bavarian Cancer Research Center (BZKF), 81377 Munich, Germany
| | - Joerg-Christian Tonn
- Department of Neurosurgery, LMU University Hospital, LMU Munich, Marchioninistr 15, 81377 Munich, Germany
- German Cancer Consortium (DKTK), Partner Site Munich, 81377 Munich, Germany
| | - Peter Bartenstein
- Department of Nuclear Medicine, LMU University Hospital, LMU Munich, Marchioninistr. 15, 81377 Munich, Germany; (L.G.)
- Munich Cluster for Systems Neurology (SyNergy), LMU Munich, 81377 Munich, Germany
- German Cancer Consortium (DKTK), Partner Site Munich, 81377 Munich, Germany
| | - Maximilian Niyazi
- Department of Radiation Oncology, LMU University Hospital, LMU Munich, Marchioninistr. 15, 81377 Munich, Germany
- Department of Radiation Oncology, University Hospital Tübingen, 72076 Tübingen, Germany
- German Cancer Consortium (DKTK), Partner Site Munich, 81377 Munich, Germany
- Bavarian Cancer Research Center (BZKF), 81377 Munich, Germany
| | - Louisa von Baumgarten
- Department of Neurosurgery, LMU University Hospital, LMU Munich, Marchioninistr 15, 81377 Munich, Germany
- German Cancer Consortium (DKTK), Partner Site Munich, 81377 Munich, Germany
- Bavarian Cancer Research Center (BZKF), 81377 Munich, Germany
| | - Roland E. Kälin
- Neurosurgical Research, Department of Neurosurgery, LMU University Hospital, LMU Munich, Marchioninistr. 15, 81377 Munich, Germany
| | - Rainer Glass
- Neurosurgical Research, Department of Neurosurgery, LMU University Hospital, LMU Munich, Marchioninistr. 15, 81377 Munich, Germany
| | - Kirsten Lauber
- Department of Radiation Oncology, LMU University Hospital, LMU Munich, Marchioninistr. 15, 81377 Munich, Germany
- German Cancer Consortium (DKTK), Partner Site Munich, 81377 Munich, Germany
| | - Nathalie L. Albert
- Department of Nuclear Medicine, LMU University Hospital, LMU Munich, Marchioninistr. 15, 81377 Munich, Germany; (L.G.)
- German Cancer Consortium (DKTK), Partner Site Munich, 81377 Munich, Germany
- Bavarian Cancer Research Center (BZKF), 81377 Munich, Germany
| | - Adrien Holzgreve
- Department of Nuclear Medicine, LMU University Hospital, LMU Munich, Marchioninistr. 15, 81377 Munich, Germany; (L.G.)
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