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Wuensche TE, Stergiou N, Mes I, Verlaan M, Schreurs M, Kooijman EJM, Janssen B, Windhorst AD, Jensen A, Asuni AA, Bang-Andersen B, Beaino W, Dongen GAMS, Vugts DJ. Advancing 89Zr-immuno-PET in neuroscience with a bispecific anti-amyloid-beta monoclonal antibody - The choice of chelator is essential. Theranostics 2022; 12:7067-7079. [PMID: 36276653 PMCID: PMC9576608 DOI: 10.7150/thno.73509] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2022] [Accepted: 08/27/2022] [Indexed: 11/05/2022] Open
Abstract
The accelerated approval of the monoclonal antibody (mAb) aducanumab as a treatment option for Alzheimer's Disease and the continued discussions about its efficacy have shown that a better understanding of immunotherapy for the treatment of neurodegenerative diseases is needed. 89Zr-immuno-PET could be a suitable tool to open new avenues for the diagnosis of CNS disorders, monitoring disease progression, and assessment of novel therapeutics. Herein, three different 89Zr-labeling strategies and direct radioiodination with 125I of a bispecific anti-amyloid-beta aducanumab derivate, consisting of aducanumab with a C-terminal fused anti-transferrin receptor binding single chain Fab fragment derived from 8D3 (Adu-8D3), were compared ex vivo and in vivo with regard to brain uptake and target engagement in an APP/PS1 Alzheimer's disease mouse model and wild type animals. Methods: Adu-8D3 and a negative control antibody, based on the HIV specific B12 antibody also carrying C-terminal fused 8D3 scFab (B12-8D3), were each conjugated with NCS-DFO, NCS-DFO*, or TFP-N-suc-DFO-Fe-ester, followed by radiolabeling with 89Zr. 125I was used as a substitute for 124I for labeling of both antibodies. 30 µg of radiolabeled mAb, corresponding to approximately 6 MBq 89Zr or 2.5 MBq 125I, were injected per mouse. PET imaging was performed 1, 3 and 7 days post injection (p.i.). All mice were sacrificed on day 7 p.i. and subjected to ex vivo biodistribution and brain autoradiography. Immunostaining on brain tissue was performed after autoradiography for further validation. Results:Ex vivo biodistribution revealed that the brain uptake of [89Zr]Zr-DFO*-NCS-Adu-8D3 (2.19 ±0.12 %ID/g) was as high as for its 125I-analog (2.21 ±0.15 %ID/g). [89Zr]Zr-DFO-NCS-Adu-8D3 and [89Zr]Zr-DFO-N-suc-Adu-8D3 showed significantly lower uptake (< 0.65 %ID/g), being in the same range as for the 89Zr-labeled controls (B12-8D3). Autoradiography of [89Zr]Zr-DFO*-NCS-Adu-8D3 and [125I]I-Adu-8D3 showed an amyloid-beta related granular uptake pattern of radioactivity. In contrast, the [89Zr]Zr-DFO-conjugates and the control antibody groups did not show any amyloid-beta related uptake pattern, indicating that DFO is inferior for 89Zr-immuno-PET imaging of the brain in comparison to DFO* for Adu-8D3. This was confirmed by day 7 PET images showing only amyloid-beta related brain uptake for [89Zr]Zr-DFO*-NCS-Adu-8D3. In wild type animals, such an uptake was not observed. Immunostaining showed a co-localization of all administered Adu-8D3 conjugates with amyloid-beta plaques. Conclusion: We successfully demonstrated that 89Zr-immuno-PET is suitable for imaging and quantifying amyloid-beta specific brain uptake using a bispecific aducanumab brain shuttling antibody, Adu-8D3, but only when using the novel chelator DFO*, and not DFO, for labeling with 89Zr.
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Ebenau JL, Visser D, Kroeze LA, van Leeuwenstijn MSSA, van Harten AC, Windhorst AD, Golla SVS, Boellaard R, Scheltens P, Barkhof F, van Berckel BNM, van der Flier WM. Longitudinal change in ATN biomarkers in cognitively normal individuals. Alzheimers Res Ther 2022; 14:124. [PMID: 36057616 PMCID: PMC9440493 DOI: 10.1186/s13195-022-01069-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2022] [Accepted: 08/23/2022] [Indexed: 04/14/2023]
Abstract
BACKGROUND Biomarkers for amyloid, tau, and neurodegeneration (ATN) have predictive value for clinical progression, but it is not clear how individuals move through these stages. We examined changes in ATN profiles over time, and investigated determinants of change in A status, in a sample of cognitively normal individuals presenting with subjective cognitive decline (SCD). METHODS We included 92 individuals with SCD from the SCIENCe project with [18F]florbetapir PET (A) available at two time points (65 ± 8y, 42% female, MMSE 29 ± 1, follow-up 2.5 ± 0.7y). We additionally used [18F]flortaucipir PET for T and medial temporal atrophy score on MRI for N. Thirty-nine individuals had complete biomarker data at baseline and follow-up, enabling the construction of ATN profiles at two time points. All underwent extensive neuropsychological assessments (follow-up time 4.9 ± 2.8y, median number of visits n = 4). We investigated changes in biomarker status and ATN profiles over time. We assessed which factors predisposed for a change from A- to A+ using logistic regression. We additionally used linear mixed models to assess change from A- to A+, compared to the group that remained A- at follow-up, as predictor for cognitive decline. RESULTS At baseline, 62% had normal AD biomarkers (A-T-N- n = 24), 5% had non-AD pathologic change (A-T-N+ n = 2,) and 33% fell within the Alzheimer's continuum (A+T-N- n = 9, A+T+N- n = 3, A+T+N+ n = 1). Seventeen subjects (44%) changed to another ATN profile over time. Only 6/17 followed the Alzheimer's disease sequence of A → T → N, while 11/17 followed a different order (e.g., reverted back to negative biomarker status). APOE ε4 carriership inferred an increased risk of changing from A- to A+ (OR 5.2 (95% CI 1.2-22.8)). Individuals who changed from A- to A+, showed subtly steeper decline on Stroop I (β - 0.03 (SE 0.01)) and Stroop III (- 0.03 (0.01)), compared to individuals who remained A-. CONCLUSION We observed considerable variability in the order of ATN biomarkers becoming abnormal. Individuals who became A+ at follow-up showed subtle decline on tests for attention and executive functioning, confirming clinical relevance of amyloid positivity.
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de Ligt R, Westerhout J, Grossouw D, Buters TP, Rissmann R, Burggraaf J, Windhorst AD, Tozer S, Pappa G, Wall B, Bury D, Mason DR, Vaes WHJ. Assessment of dermal absorption of aluminium from a representative antiperspirant formulation using a (26Al)Al microtracer approach: a follow-up study in humans. Toxicol Res (Camb) 2022; 11:511-519. [PMID: 35782644 PMCID: PMC9244721 DOI: 10.1093/toxres/tfac029] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2021] [Revised: 03/21/2022] [Accepted: 05/05/2022] [Indexed: 11/22/2022] Open
Abstract
A follow-up study was performed in 12 healthy women to evaluate systemic exposure to aluminium following topical application of a representative antiperspirant formulation under real-life use conditions (part A) and to assess the local fate of topically applied aluminium by taking additional tape strips and skin biopsies (Part B). A simple roll-on formulation, containing the maximal possible radioactive dose, was prepared with [26Al] aluminium-labeled chlorohydrate (ACH). The microtracer of [26Al] was used to distinguish aluminium from the natural background, using accelerator mass spectrometry. [26Al] aluminiumcitrate was administered intravenously to estimate the dermal fraction absorbed. Despite the 25-fold increase of the topical dose compared with the previous study, only 12 blood samples gave results above the lower limit of quantitation (0.118 fg/mL). The most reliable estimates of the dermal fraction absorbed are derived from noncompartmental analysis with the urine data. By using the intravenous dose to normalize the urinary excretion to 100% bioavailability, the best estimate of the fraction absorbed of [26Al] from a topical application of [26Al]-aluminium-labeled chlorohydrate in an antiperspirant formulation was 0.00052%. Part B of the study demonstrated that the majority of the aluminium in the formulation remained associated with the external layers of the skin without penetration through the skin.
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Meijer L, Böszörményi KP, Bakker J, Koopman G, Mooij P, Verel D, Fagrouch Z, Verstrepen BE, Funke U, Mooijer MPJ, Langermans JAM, Verschoor EJ, Windhorst AD, Stammes MA. Novel application of [ 18F]DPA714 for visualizing the pulmonary inflammation process of SARS-CoV-2-infection in rhesus monkeys (Macaca mulatta). Nucl Med Biol 2022; 112-113:1-8. [PMID: 35660200 PMCID: PMC9148436 DOI: 10.1016/j.nucmedbio.2022.05.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2022] [Revised: 05/12/2022] [Accepted: 05/19/2022] [Indexed: 11/06/2022]
Abstract
Rationale The aim of this study was to investigate the application of [18F]DPA714 to visualize the inflammation process in the lungs of SARS-CoV-2-infected rhesus monkeys, focusing on the presence of pulmonary lesions, activation of mediastinal lymph nodes and surrounded lung tissue. Methods Four experimentally SARS-CoV-2 infected rhesus monkeys were followed for seven weeks post infection (pi) with a weekly PET-CT using [18F]DPA714. Two PET images, 10 min each, of a single field-of-view covering the chest area, were obtained 10 and 30 min after injection. To determine the infection process swabs, blood and bronchoalveolar lavages (BALs) were obtained. Results All animals were positive for SARS-CoV-2 in both the swabs and BALs on multiple timepoints pi. The initial development of pulmonary lesions was already detected at the first scan, performed 2-days pi. PET revealed an increased tracer uptake in the pulmonary lesions and mediastinal lymph nodes of all animals from the first scan obtained after infection and onwards. However, also an increased uptake was detected in the lung tissue surrounding the lesions, which persisted until day 30 and then subsided by day 37–44 pi. In parallel, a similar pattern of increased expression of activation markers was observed on dendritic cells in blood. Principal conclusions This study illustrates that [18F]DPA714 is a valuable radiotracer to visualize SARS-CoV-2-associated pulmonary inflammation, which coincided with activation of dendritic cells in blood. [18F]DPA714 thus has the potential to be of added value as diagnostic tracer for other viral respiratory infections. [18F]DPA714 PET can visualize alterations in the lungs after a SARS-CoV-2 infection. The PET signal increases in unaffected lung tissue till day 30 post infection. Dendritic cell activation in blood is increased till day 30/37 post infection
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Rotteveel L, Kurakula K, Kooijman EJM, Schuit RC, Verlaan M, Schreurs M, Beaino W, van Dinther MAH, Ten Dijke P, Lammertsma AA, Poot AJ, Bogaard HJ, Windhorst AD. Synthesis and preclinical evaluation of [ 11C]LR111 and [ 18F]EW-7197 as PET tracers of the activin-receptor like kinase-5. Nucl Med Biol 2022; 112-113:9-19. [PMID: 35660796 DOI: 10.1016/j.nucmedbio.2022.05.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2022] [Revised: 05/12/2022] [Accepted: 05/19/2022] [Indexed: 10/18/2022]
Abstract
The transforming growth factor β (TGFβ) pathway plays a complex role in cancer biology, being involved in both tumour suppression as well as promotion. Overactive TGFβ signalling has been linked to multiple diseases, including cancer, pulmonary arterial hypertension, and fibrosis. One of the key meditators within this pathway is the TGFβ type I receptor, also termed activin receptor-like kinase 5 (ALK5). ALK5 expression level is a key determinant of TGFβ signalling intensity and duration, and perturbation has been linked to diseases. A validated ALK5 positron emission tomography (PET) tracer creates an opportunity, therefore, to study its role in human diseases. To develop ALK5 PET tracers, two small molecule ALK5 kinase inhibitors were selected as lead compounds, which were labelled with carbon-11 and fluorine-18, respectively. [11C]LR111 was synthesized with a yield of 17 ± 6%, a molar activity of 126 ± 79 GBq·μmol-1 and a purity of >95% (n = 44). [18F]EW-7197 was synthesized with a yield of 10 ± 5%, a molar activity of 183 ± 126 GBq·μmol-1 and a purity of >95% (n = 11). Metabolic stability was evaluated in vivo in mice, showing 39 ± 2% of intact [11C]LR111 and 21 ± 2% of intact [18F]EW-7197 in blood plasma at 45 min p.i. In vitro binding experiments were conducted in breast cancer MDA-MB-231 and lung cancer A431 cell lines. In addition, both tracers were used for PET imaging in MDA-MB-231 xenograft models. Selective uptake of [18F]EW-7197 and [11C]LR111 was observed in MDA-MB-231 cells, in the MDA-MB-231 tumour xenografts in vivo and in the autoradiograms. As [11C]LR111 and [18F]EW-7197 showed selectivity of binding to ALK5 in vivo and in vitro. Both tracers are thereby valuable tools for the detection of ALK5 activity.
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Lumen D, Vugts D, Chomet M, Imlimthan S, Sarparanta M, Vos R, Schreurs M, Verlaan M, Lang PA, Hippeläinen E, Beaino W, Windhorst AD, Airaksinen AJ. Pretargeted PET Imaging with a TCO-Conjugated Anti-CD44v6 Chimeric mAb U36 and [ 89Zr]Zr-DFO-PEG 5-Tz. Bioconjug Chem 2022; 33:956-968. [PMID: 35442642 PMCID: PMC9121349 DOI: 10.1021/acs.bioconjchem.2c00164] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
![]()
The recent advances
in the production of engineered antibodies
have facilitated the development and application of tailored, target-specific
antibodies. Positron emission tomography (PET) of these antibody-based
drug candidates can help to better understand their in vivo behavior. In this study, we report an in vivo proof-of-concept
pretargeted immuno-PET study where we compare a pretargeting vs targeted
approach using a new 89Zr-labeled tetrazine as a bio-orthogonal
ligand in an inverse electron demand Diels–Alder (IEDDA) in vivo click reaction. A CD44v6-selective chimeric monoclonal
U36 was selected as the targeting antibody because it has potential
in immuno-PET imaging of head-and-neck squamous cell carcinoma (HNSCC).
Zirconium-89 (t1/2 = 78.41 h) was selected
as the radionuclide of choice to be able to make a head-to-head comparison
of the pretargeted and targeted approaches. [89Zr]Zr-DFO-PEG5-Tz ([89Zr]Zr-3) was synthesized and
used in pretargeted PET imaging of HNSCC xenografts (VU-SCC-OE) at
24 and 48 h after administration of a trans-cyclooctene
(TCO)-functionalized U36. The pretargeted approach resulted in lower
absolute tumor uptake than the targeted approach (1.5 ± 0.2 vs
17.1 ± 3.0% ID/g at 72 h p.i. U36) but with comparable tumor-to-non-target
tissue ratios and significantly lower absorbed doses. In conclusion,
anti-CD44v6 monoclonal antibody U36 was successfully used for 89Zr-immuno-PET imaging of HNSCC xenograft tumors using both
a targeted and pretargeted approach. The results not only support
the utility of the pretargeted approach in immuno-PET imaging but
also demonstrate the challenges in achieving optimal in vivo IEDDA reaction efficiencies in relation to antibody pharmacokinetics.
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Högnäsbacka A, Poot AJ, Vugts DJ, van Dongen GAMS, Windhorst AD. The Development of Positron Emission Tomography Tracers for In Vivo Targeting the Kinase Domain of the Epidermal Growth Factor Receptor. Pharmaceuticals (Basel) 2022; 15:ph15040450. [PMID: 35455447 PMCID: PMC9033078 DOI: 10.3390/ph15040450] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2022] [Revised: 03/24/2022] [Accepted: 03/25/2022] [Indexed: 11/16/2022] Open
Abstract
Multiple small molecule PET tracers have been developed for the imaging of the epidermal growth factor receptor (EGFR). These tracers target the tyrosine kinase (TK) domain of the receptor and have been used for both quantifying EGFR expression and to differentiate between EGFR mutational statuses. However, the approaches for in vivo evaluation of these tracers are diverse and have resulted in data that are hard to compare. In this review, we analyze the historical development of the in vivo evaluation approaches, starting from the first EGFR TK PET tracer [11C]PD153035 to tracers developed based on TK inhibitors used for the clinical treatment of mutated EGFR expressing non-small cell lung cancer like [11C]erlotinib and [18F]afatinib. The evaluation of each tracer has been compiled to allow for a comparison between studies and ultimately between tracers. The main challenges for each group of tracers are thereafter discussed. Finally, this review addresses the challenges that need to be overcome to be able to efficiently drive EGFR PET imaging forward.
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Steinz MM, Ezdoglian A, Khodadust F, Molthoff CFM, Srinivasarao M, Low PS, Zwezerijnen GJC, Yaqub M, Beaino W, Windhorst AD, Tas SW, Jansen G, van der Laken CJ. Folate Receptor Beta for Macrophage Imaging in Rheumatoid Arthritis. Front Immunol 2022; 13:819163. [PMID: 35185910 PMCID: PMC8849105 DOI: 10.3389/fimmu.2022.819163] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2021] [Accepted: 01/11/2022] [Indexed: 12/30/2022] Open
Abstract
Non-invasive imaging modalities constitute an increasingly important tool in diagnostic and therapy response monitoring of patients with autoimmune diseases, including rheumatoid arthritis (RA). In particular, macrophage imaging with positron emission tomography (PET) using novel radiotracers based on differential expression of plasma membrane proteins and functioning of cellular processes may be suited for this. Over the past decade, selective expression of folate receptor β (FRβ), a glycosylphosphatidylinositol-anchored plasma membrane protein, on myeloid cells has emerged as an attractive target for macrophage imaging by exploiting the high binding affinity of folate-based PET tracers. This work discusses molecular, biochemical and functional properties of FRβ, describes the preclinical development of a folate-PET tracer and the evaluation of this tracer in a translational model of arthritis for diagnostics and therapy-response monitoring, and finally the first clinical application of the folate-PET tracer in RA patients with active disease. Consequently, folate-based PET tracers hold great promise for macrophage imaging in a variety of (chronic) inflammatory (autoimmune) diseases beyond RA.
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van der Wildt B, Janssen B, Pekošak A, Stéen EJL, Schuit RC, Kooijman EJM, Beaino W, Vugts DJ, Windhorst AD. Correction to Novel Thienopyrimidine-Based PET Tracers for P2Y 12 Receptor Imaging in the Brain. ACS Chem Neurosci 2022; 13:847. [PMID: 35191680 PMCID: PMC9060419 DOI: 10.1021/acschemneuro.2c00110] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
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Tuncel H, Boellaard R, Coomans EM, Hollander-Meeuwsen MD, de Vries EFJ, Glaudemans AWJM, Feltes PK, García DV, Verfaillie SCJ, Wolters EE, Sweeney SP, Ryan JM, Ivarsson M, Lynch BA, Schober P, Scheltens P, Schuit RC, Windhorst AD, De Deyn PP, van Berckel BNM, Golla SSV. Validation and test–retest repeatability performance of parametric methods for [11C]UCB-J PET. EJNMMI Res 2022; 12:3. [PMID: 35072802 PMCID: PMC8786991 DOI: 10.1186/s13550-021-00874-8] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2021] [Accepted: 12/24/2021] [Indexed: 12/02/2022] Open
Abstract
[11C]UCB-J is a PET radioligand that binds to the presynaptic vesicle glycoprotein 2A. Therefore, [11C]UCB-J PET may serve as an in vivo marker of synaptic integrity. The main objective of this study was to evaluate the quantitative accuracy and the 28-day test–retest repeatability (TRT) of various parametric quantitative methods for dynamic [11C]UCB-J studies in Alzheimer’s disease (AD) patients and healthy controls (HC). Eight HCs and seven AD patients underwent two 60-min dynamic [11C]UCB-J PET scans with arterial sampling over a 28-day interval. Several plasma-input based and reference-region based parametric methods were used to generate parametric images using metabolite corrected plasma activity as input function or white matter semi-ovale as reference region. Different parametric outcomes were compared regionally with corresponding non-linear regression (NLR) estimates. Furthermore, the 28-day TRT was assessed for all parametric methods. Spectral analysis (SA) and Logan graphical analysis showed high correlations with NLR estimates. Receptor parametric mapping (RPM) and simplified reference tissue model 2 (SRTM2) BPND, and reference Logan (RLogan) distribution volume ratio (DVR) regional estimates correlated well with plasma-input derived DVR and SRTM BPND. Among the multilinear reference tissue model (MRTM) methods, MRTM1 had the best correspondence with DVR and SRTM BPND. Among the parametric methods evaluated, spectral analysis (SA) and SRTM2 were the best plasma-input and reference tissue methods, respectively, to obtain quantitatively accurate and repeatable parametric images for dynamic [11C]UCB-J PET.
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Coomans EM, Tomassen J, Ossenkoppele R, Golla SSV, den Hollander M, Collij LE, Weltings E, van der Landen S, Wolters EE, Windhorst AD, Barkhof F, de Geus EJ, Scheltens P, Visser PJ, van Berckel BNM, den Braber A. Genetically identical twins show comparable tau PET load and spatial distribution. Brain 2022; 145:3571-3581. [PMID: 35022652 PMCID: PMC9586544 DOI: 10.1093/brain/awac004] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2021] [Revised: 11/05/2021] [Accepted: 11/26/2021] [Indexed: 11/13/2022] Open
Abstract
Tau accumulation starts during the preclinical phase of Alzheimer’s disease and is closely associated with cognitive decline. For preventive purposes, it is important to identify factors associated with tau accumulation and spread. Studying genetically identical twin-pairs may give insight into genetic and environmental contributions to tau pathology, as similarities in identical twin-pairs largely result from genetic factors, while differences in identical twin-pairs can largely be attributed to non-shared, environmental factors. This study aimed to examine similarities and dissimilarities in a cohort of genetically identical older twin-pairs in (i) tau load; and (ii) spatial distribution of tau, measured with 18F-flortaucipir PET. We selected 78 genetically identical twins (39 pairs; average age 73 ± 6 years), enriched for amyloid-β pathology and APOE ε4 carriership, who underwent dynamic 18F-flortaucipir PET. We extracted binding potentials (BPND) in entorhinal, temporal, widespread neocortical and global regions, and examined within-pair similarities in BPND using age and sex corrected intra-class correlations. Furthermore, we tested whether twin-pairs showed a more similar spatial 18F-flortaucipir distribution compared to non-twin pairs, and whether the participant’s co-twin could be identified solely based on the spatial 18F-flortaucipir distribution. Last, we explored whether environmental (e.g. physical activity, obesity) factors could explain observed differences in twins of a pair in 18F-flortaucipir BPND. On visual inspection, Alzheimer’s disease-like 18F-flortaucipir PET patterns were observed, and although we mainly identified similarities in twin-pairs, some pairs showed strong dissimilarities. 18F-flortaucipir BPND was correlated in twins in the entorhinal (r = 0.40; P = 0.01), neocortical (r = 0.59; P < 0.01) and global (r = 0.56; P < 0.01) regions, but not in the temporal region (r = 0.20; P = 0.10). The 18F-flortaucipir distribution pattern was significantly more similar between twins of the same pair [mean r = 0.27; standard deviation (SD) = 0.09] than between non-twin pairings of participants (mean r = 0.01; SD = 0.10) (P < 0.01), also after correcting for proxies of off-target binding. Based on the spatial 18F-flortaucipir distribution, we could identify with an accuracy of 86% which twins belonged to the same pair. Finally, within-pair differences in 18F-flortaucipir BPND were associated with within-pair differences in depressive symptoms (0.37 < β < 0.56), physical activity (−0.41 < β < −0.42) and social activity (−0.32 < β < −0.36) (all P < 0.05). Overall, identical twin-pairs were comparable in tau load and spatial distribution, highlighting the important role of genetic factors in the accumulation and spreading of tau pathology. Considering also the presence of dissimilarities in tau pathology in identical twin-pairs, our results additionally support a role for (potentially modifiable) environmental factors in the onset of Alzheimer’s disease pathological processes, which may be of interest for future prevention strategies.
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Barca C, Griessinger CM, Faust A, Depke D, Essler M, Windhorst AD, Devoogdt N, Brindle KM, Schäfers M, Zinnhardt B, Jacobs AH. Expanding Theranostic Radiopharmaceuticals for Tumor Diagnosis and Therapy. Pharmaceuticals (Basel) 2021; 15:13. [PMID: 35056071 PMCID: PMC8780589 DOI: 10.3390/ph15010013] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2021] [Revised: 12/16/2021] [Accepted: 12/16/2021] [Indexed: 02/06/2023] Open
Abstract
Radioligand theranostics (RT) in oncology use cancer-type specific biomarkers and molecular imaging (MI), including positron emission tomography (PET), single-photon emission computed tomography (SPECT) and planar scintigraphy, for patient diagnosis, therapy, and personalized management. While the definition of theranostics was initially restricted to a single compound allowing visualization and therapy simultaneously, the concept has been widened with the development of theranostic pairs and the combination of nuclear medicine with different types of cancer therapies. Here, we review the clinical applications of different theranostic radiopharmaceuticals in managing different tumor types (differentiated thyroid, neuroendocrine prostate, and breast cancer) that support the combination of innovative oncological therapies such as gene and cell-based therapies with RT.
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van Dam MA, Vuijk FA, Stibbe JA, Houvast RD, Luelmo SAC, Crobach S, Shahbazi Feshtali S, de Geus-Oei LF, Bonsing BA, Sier CFM, Kuppen PJK, Swijnenburg RJ, Windhorst AD, Burggraaf J, Vahrmeijer AL, Mieog JSD. Overview and Future Perspectives on Tumor-Targeted Positron Emission Tomography and Fluorescence Imaging of Pancreatic Cancer in the Era of Neoadjuvant Therapy. Cancers (Basel) 2021; 13:6088. [PMID: 34885196 PMCID: PMC8656821 DOI: 10.3390/cancers13236088] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2021] [Revised: 11/25/2021] [Accepted: 11/28/2021] [Indexed: 02/05/2023] Open
Abstract
BACKGROUND Despite recent advances in the multimodal treatment of pancreatic ductal adenocarcinoma (PDAC), overall survival remains poor with a 5-year cumulative survival of approximately 10%. Neoadjuvant (chemo- and/or radio-) therapy is increasingly incorporated in treatment strategies for patients with (borderline) resectable and locally advanced disease. Neoadjuvant therapy aims to improve radical resection rates by reducing tumor mass and (partial) encasement of important vascular structures, as well as eradicating occult micrometastases. Results from recent multicenter clinical trials evaluating this approach demonstrate prolonged survival and increased complete surgical resection rates (R0). Currently, tumor response to neoadjuvant therapy is monitored using computed tomography (CT) following the RECIST 1.1 criteria. Accurate assessment of neoadjuvant treatment response and tumor resectability is considered a major challenge, as current conventional imaging modalities provide limited accuracy and specificity for discrimination between necrosis, fibrosis, and remaining vital tumor tissue. As a consequence, resections with tumor-positive margins and subsequent early locoregional tumor recurrences are observed in a substantial number of patients following surgical resection with curative intent. Of these patients, up to 80% are diagnosed with recurrent disease after a median disease-free interval of merely 8 months. These numbers underline the urgent need to improve imaging modalities for more accurate assessment of therapy response and subsequent re-staging of disease, thereby aiming to optimize individual patient's treatment strategy. In cases of curative intent resection, additional intra-operative real-time guidance could aid surgeons during complex procedures and potentially reduce the rate of incomplete resections and early (locoregional) tumor recurrences. In recent years intraoperative imaging in cancer has made a shift towards tumor-specific molecular targeting. Several important molecular targets have been identified that show overexpression in PDAC, for example: CA19.9, CEA, EGFR, VEGFR/VEGF-A, uPA/uPAR, and various integrins. Tumor-targeted PET/CT combined with intraoperative fluorescence imaging, could provide valuable information for tumor detection and staging, therapy response evaluation with re-staging of disease and intraoperative guidance during surgical resection of PDAC. METHODS A literature search in the PubMed database and (inter)national trial registers was conducted, focusing on studies published over the last 15 years. Data and information of eligible articles regarding PET/CT as well as fluorescence imaging in PDAC were reviewed. Areas covered: This review covers the current strategies, obstacles, challenges, and developments in targeted tumor imaging, focusing on the feasibility and value of PET/CT and fluorescence imaging for integration in the work-up and treatment of PDAC. An overview is given of identified targets and their characteristics, as well as the available literature of conducted and ongoing clinical and preclinical trials evaluating PDAC-targeted nuclear and fluorescent tracers.
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Stergiou N, Wünsche T, Mes I, Schreurs M, Verlaan M, Kooijman E, Windhorst AD, Dongen GAMS, Helboe L, Vergo S, Christensen S, Asuni AA, Jensen A, Bang‐Andersen B, Vugts D, Beaino W. Visualization of brain targets with
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Zr‐immuno‐PET using a novel bispecific amyloid ß monoclonal antibody. Alzheimers Dement 2021. [DOI: 10.1002/alz.053052] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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van der Wildt B, Janssen B, Pekošak A, Stéen EJL, Schuit RC, Kooijman EJM, Beaino W, Vugts DJ, Windhorst AD. Novel Thienopyrimidine-Based PET Tracers for P2Y 12 Receptor Imaging in the Brain. ACS Chem Neurosci 2021; 12:4465-4474. [PMID: 34757711 PMCID: PMC8640995 DOI: 10.1021/acschemneuro.1c00641] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
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The P2Y12 receptor (P2Y12R) is uniquely expressed
on microglia in the brain, and its expression level directly depends
on the microglial activation state. Therefore, P2Y12R provides
a promising imaging marker for distinguishing the pro- and anti-inflammatory
microglial phenotypes, both of which play crucial roles in neuroinflammatory
diseases. In this study, three P2Y12R antagonists were
selected from the literature, radiolabeled with carbon-11 or fluorine-18,
and evaluated in healthy Wistar rats. Brain imaging was performed
with and without blocking of efflux transporters P-glycoprotein and breast cancer resistance protein using tariquidar.
Low brain uptake in healthy rats was observed for all tracers at baseline
conditions, whereas blocking of efflux transporters resulted in a
strong (6–7 fold) increase in brain uptake for both of them.
Binding of the most promising tracer, [18F]3, was further evaluated by in vitro autoradiography on rat brain
sections, ex vivo metabolite studies, and in vivo P2Y12R blocking studies. In vitro binding of [18F]3 on rat brain sections indicated high P2Y12R targeting
with approximately 70% selective and specific binding. At 60 min post-injection,
over 95% of radioactivity in the brain accounted for an intact tracer.
In blood plasma, still 40% intact tracer was found, and formed metabolites
did not enter the brain. A moderate P2Y12R blocking effect
was observed in vivo by positron emission tomography (PET) imaging
with [18F]3 (p = 0.04). To
conclude, three potential P2Y12R PET tracers were obtained
and analyzed for P2Y12R targeting in the brain. Unfortunately,
the brain uptake appeared low. Future work will focus on the design
of P2Y12R inhibitors with improved physicochemical characteristics
to reduce efflux transport and increase brain penetration.
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Coomans EM, Tomassen J, Ossenkoppele R, Golla SSV, den Hollander ME, Collij LE, Weltings E, Hoogland N, Wolters EE, Windhorst AD, Barkhof F, de Geus EJ, Scheltens P, Visser PJ, Van Berckel BN, den Braber A. Genetically identical twins are highly similar in levels and spatial distribution of tau pathology: A [
18
F]flortaucipir PET study. Alzheimers Dement 2021. [DOI: 10.1002/alz.054879] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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Pees A, Beaino W, Kooijman EJM, Schreurs M, Verlaan M, Schuit RC, Vosjan MJWD, Engelsman AF, Windhorst AD, Vugts DJ. Synthesis and evaluation of [ 18F]cinacalcet for the imaging of parathyroid hyperplasia. Nucl Med Biol 2021; 102-103:97-105. [PMID: 34743064 DOI: 10.1016/j.nucmedbio.2021.10.003] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2021] [Revised: 09/15/2021] [Accepted: 10/23/2021] [Indexed: 10/20/2022]
Abstract
INTRODUCTION Parathyroid hyperplasia is a disease characterized by overactive parathyroid glands secreting increased levels of parathyroid hormone. Surgical removal of the parathyroid glands is the standard treatment but requires precise pre-operative localization of the glands. However, currently available imaging modalities show limited sensitivity. Since positron emission tomography (PET) is a molecular imaging technique with high accuracy and sensitivity, our aim was to develop a new PET tracer for overactive parathyroid glands imaging by radiolabelling cinacalcet, a drug binding to the calcium-sensing receptor of the parathyroid glands. METHODS [18F]Cinacalcet was synthesized by copper-catalysed [18F]trifluoromethylation of a boronic acid precursor using high molar activity [18F]fluoroform. Ex vivo biodistribution and metabolism were evaluated in 12 healthy male Wistar rats at 5, 15, 45 and 90 min. PET scans were performed at baseline and after blocking with NPS R-568. RESULTS [18F]Cinacalcet was obtained in an overall radiosynthesis time of 1 h with a radiochemical purity of 98 ± 1%, a radiochemical yield of 8 ± 4% (overall, n = 7, corrected for decay) and a molar activity of 40 ± 11 GBq/μmol (n = 7, at EOS). The ex vivo biodistribution showed uptake in the thyroid and parathyroid glands as well as in other glands such as adrenals, salivary glands and pancreas. The tracer was rapidly cleared from the blood via liver and kidneys and showed fast metabolism. PET images confirmed uptake in the target organ. However, in a blocking study with NPS R-568 specific binding of [18F]cinacalcet to the CaSR could not be confirmed. CONCLUSIONS [18F]Cinacalcet was successfully synthesized. First in vivo experiments in healthy rats showed uptake of the tracer in the target organ and fast metabolism, encouraging further in vivo evaluation of this tracer.
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Bidesi NSR, Vang Andersen I, Windhorst AD, Shalgunov V, Herth MM. The role of neuroimaging in Parkinson's disease. J Neurochem 2021; 159:660-689. [PMID: 34532856 PMCID: PMC9291628 DOI: 10.1111/jnc.15516] [Citation(s) in RCA: 25] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2021] [Revised: 09/09/2021] [Accepted: 09/10/2021] [Indexed: 11/29/2022]
Abstract
Parkinson's disease (PD) is a neurodegenerative disorder that affects millions of people worldwide. Two hallmarks of PD are the accumulation of alpha-synuclein and the loss of dopaminergic neurons in the brain. There is no cure for PD, and all existing treatments focus on alleviating the symptoms. PD diagnosis is also based on the symptoms, such as abnormalities of movement, mood, and cognition observed in the patients. Molecular imaging methods such as magnetic resonance imaging (MRI), single-photon emission computed tomography (SPECT), and positron emission tomography (PET) can detect objective alterations in the neurochemical machinery of the brain and help diagnose and study neurodegenerative diseases. This review addresses the application of functional MRI, PET, and SPECT in PD patients. We provide an overview of the imaging targets, discuss the rationale behind target selection, the agents (tracers) with which the imaging can be performed, and the main findings regarding each target's state in PD. Molecular imaging has proven itself effective in supporting clinical diagnosis of PD and has helped reveal that PD is a heterogeneous disorder, which has important implications for the development of future therapies. However, the application of molecular imaging for early diagnosis of PD or for differentiation between PD and atypical parkinsonisms has remained challenging. The final section of the review is dedicated to new imaging targets with which one can detect the PD-related pathological changes upstream from dopaminergic degeneration. The foremost of those targets is alpha-synuclein. We discuss the progress of tracer development achieved so far and challenges on the path toward alpha-synuclein imaging in humans.
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Wolters EE, Papma JM, Verfaillie SCJ, Visser D, Weltings E, Groot C, van der Ende EL, Giannini LAA, Tuncel H, Timmers T, Boellaard R, Yaqub M, van Assema DME, Kuijper DA, Segbers M, Rozemuller AJM, Barkhof F, Windhorst AD, van der Flier WM, Pijnenburg YAL, Scheltens P, van Berckel BNM, van Swieten JC, Ossenkoppele R, Seelaar H. [ 18F]Flortaucipir PET Across Various MAPT Mutations in Presymptomatic and Symptomatic Carriers. Neurology 2021; 97:e1017-e1030. [PMID: 34210823 PMCID: PMC8448551 DOI: 10.1212/wnl.0000000000012448] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2021] [Accepted: 06/07/2021] [Indexed: 11/15/2022] Open
Abstract
OBJECTIVE To assess the [18F]flortaucipir binding distribution across MAPT mutations in presymptomatic and symptomatic carriers. METHODS We compared regional [18F]flortaucipir binding potential (BPND) derived from a 130-minute dynamic [18F]flortaucipir PET scan in 9 (pre)symptomatic MAPT mutation carriers (4 with P301L [1 symptomatic], 2 with R406W [1 symptomatic], 1 presymptomatic L315R, 1 presymptomatic S320F, and 1 symptomatic G272V carrier) with 30 cognitively normal controls and 52 patients with Alzheimer disease. RESULTS [18F]Flortaucipir BPND images showed overall highest binding in the symptomatic carriers. This was most pronounced in the symptomatic R406W carrier in whom tau binding exceeded the normal control range in the anterior cingulate cortex, insula, amygdala, temporal, parietal, and frontal lobe. Elevated medial temporal lobe BPND was observed in a presymptomatic R406W carrier. The single symptomatic carrier and 1 of the 3 presymptomatic P301L carriers showed elevated [18F]flortaucipir BPND in the insula, parietal, and frontal lobe compared to controls. The symptomatic G272V carrier exhibited a widespread elevated cortical BPND, with at neuropathologic examination a combination of 3R pathology and encephalitis. The L315R presymptomatic mutation carrier showed higher frontal BPND compared to controls. The BPND values of the S320F presymptomatic mutation carrier fell within the range of controls. CONCLUSION Presymptomatic MAPT mutation carriers already showed subtle elevated tau binding, whereas symptomatic MAPT mutation carriers showed a more marked increase in [18F]flortaucipir BPND. Tau deposition was most pronounced in R406W MAPT (pre)symptomatic mutation carriers, which is associated with both 3R and 4R tau accumulation. Thus, [18F]flortaucipir may serve as an early biomarker for MAPT mutation carriers in mutations that cause 3R/4R tauopathies.
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Feiner IVJ, Longo B, Gómez-Vallejo V, Calvo J, Chomet M, Vugts DJ, Windhorst AD, Padro D, Zanda M, Rejc L, Llop J. Comparison of analytical methods for antibody conjugates with application in nuclear imaging - Report from the trenches. Nucl Med Biol 2021; 102-103:24-33. [PMID: 34492606 DOI: 10.1016/j.nucmedbio.2021.08.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2021] [Accepted: 08/15/2021] [Indexed: 10/20/2022]
Abstract
INTRODUCTION Monoclonal antibodies (mAbs) are widely used in nuclear imaging. Radiolabelling with positron emitting radionuclides, typically radiometals, requires the incorporation of a bifunctional chelator for the formation of the radiometal-mAb complex. Additionally, mAbs can be conjugated with small molecules capable to undergo bioorthogonal click reactions in vivo, enabling pre-targeting strategies. The determination of the number of functionalities attached to the mAb is critically important to ensure a good labelling yield or to guarantee pre-targeting efficacy. In this work, we compare three different analytical methods for the assessment of average functionalisation and heterogeneity of the conjugated mAbs. METHODS Two selected mAbs (Trastuzumab and Bevacizumab) were randomly conjugated through lysine residues with 3-10 equivalents p-isothiocyanatobenzyl-desferrioxamine (p-NCS-Bz-DFO) or 20-200 equivalents trans-cyclooctene-N-hydroxysuccinimide ester (TCO-NHS). The DFO- or TCO-to-mAb ratio were determined using three different methods: direct titration (radiometric for DFO-conjugated mAbs, photometric for TCO-conjugated mAbs), MALDI/TOF MS mass analysis (Matrix-Assisted Laser Desorption-Ionization/Time of Flight Mass Spectrometry), and UPLC/ESI-TOF MS mass analysis (Ultra High Performance Liquid Chromatography/Electrospray Ionization-Time of Flight Mass Spectrometry). RESULTS Radiometric and photometric titrations provided information on the average number of DFO and TCO functionalities per mAb respectively. MALDI/TOF MS provided equivalent results to those obtained by titration, although investigation of the heterogeneity of the resulting mixture was challenging and inaccurate. UPLC/ESI-TOF MS resulted in good peak resolution in the case of DFO-conjugated mAbs, where an accurate discrimination of the contribution of mono-, di- and tri-substituted mAbs could be achieved by mathematical fitting of the spectra. However, UPLC/ESI-TOF MS was unable to discriminate between different conjugates when the smaller TCO moiety was attached to the mAbs. CONCLUSIONS The three techniques offered comparable results in terms of determining the average number of conjugates per mAb. Additionally, UPLC/ESI-TOF MS was able to shed a light on the heterogeneity of the resulting functionalised mAbs, especially in the case of DFO-conjugated mAbs. Finally, while using a single analytical method might not be a reliable way to determine the average functionalisation and assess the heterogeneity of the sample, a combination of these methods could substantially improve the characterization of mAb conjugates.
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Pees A, Vosjan MJWD, Chai JY, Cha H, Chi DY, Windhorst AD, Vugts DJ. Evaluating N-difluoromethyltriazolium triflate as a precursor for the synthesis of high molar activity [ 18 F]fluoroform. J Labelled Comp Radiopharm 2021; 64:466-476. [PMID: 34382259 PMCID: PMC9293032 DOI: 10.1002/jlcr.3939] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2021] [Revised: 08/01/2021] [Accepted: 08/03/2021] [Indexed: 01/24/2023]
Abstract
The trifluoromethyl group is a prominent motif in biologically active compounds and therefore of great interest for the labeling with the positron emitter fluorine‐18 for positron emission tomography (PET) imaging. Multiple labeling strategies have been explored in the past; however, most of them suffer from low molar activity due to precursor degradation. In this study, the potential of 1‐(difluoromethyl)‐3‐methyl‐4‐phenyl‐1H‐1,2,3‐triazol‐3‐ium triflate as precursor for the synthesis of the [18F]trifluoromethylation building block [18F]fluoroform with high molar activity was investigated. The triazolium precursor was reacted under various conditions with [18F]fluoride, providing [18F]fluoroform with radiochemical yields (RCY) and molar activities (Am) comparable and even superior with already existing methods. Highest molar activities (Am = 153 ± 14 GBq/μmol, dc, EOS) were observed for the automated procedure on the Neptis® perform module. Due to its easy handling and good RCY and Am in the [18F]fluoroform synthesis, the triazolium precursor is a valuable alternative to already known precursors.
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Beaino W, Janssen B, Vugts DJ, de Vries HE, Windhorst AD. Towards PET imaging of the dynamic phenotypes of microglia. Clin Exp Immunol 2021; 206:282-300. [PMID: 34331705 PMCID: PMC8561701 DOI: 10.1111/cei.13649] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2021] [Revised: 07/21/2021] [Accepted: 07/21/2021] [Indexed: 02/06/2023] Open
Abstract
There is increasing evidence showing the heterogeneity of microglia activation in neuroinflammatory and neurodegenerative diseases. It has been hypothesized that pro‐inflammatory microglia are detrimental and contribute to disease progression, while anti‐inflammatory microglia play a role in damage repair and remission. The development of therapeutics targeting the deleterious glial activity and modulating it into a regenerative phenotype relies heavily upon a clearer understanding of the microglia dynamics during disease progression and the ability to monitor therapeutic outcome in vivo. To that end, molecular imaging techniques are required to assess microglia dynamics and study their role in disease progression as well as to evaluate the outcome of therapeutic interventions. Positron emission tomography (PET) is such a molecular imaging technique, and provides unique capabilities for non‐invasive quantification of neuroinflammation and has the potential to discriminate between microglia phenotypes and define their role in the disease process. However, several obstacles limit the possibility for selective in vivo imaging of microglia phenotypes mainly related to the poor characterization of specific targets that distinguish the two ends of the microglia activation spectrum and lack of suitable tracers. PET tracers targeting translocator protein 18 kDa (TSPO) have been extensively explored, but despite the success in evaluating neuroinflammation they failed to discriminate between microglia activation statuses. In this review, we highlight the current knowledge on the microglia phenotypes in the major neuroinflammatory and neurodegenerative diseases. We also discuss the current and emerging PET imaging targets, the tracers and their potential in discriminating between the pro‐ and anti‐inflammatory microglia activation states.
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van der Wildt B, Nezam M, Kooijman EJ, Reyes ST, Shen B, Windhorst AD, Chin FT. Evaluation of carbon-11 labeled 5-(1-methyl-1H-pyrazol-4-yl)-N-(2-methyl-5-(3-(trifluoromethyl)benzamido)phenyl)nicotinamide as PET tracer for imaging of CSF-1R expression in the brain. Bioorg Med Chem 2021; 42:116245. [DOI: 10.1016/j.bmc.2021.116245] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2021] [Revised: 05/25/2021] [Accepted: 05/26/2021] [Indexed: 12/14/2022]
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Chomet M, Schreurs M, Vos R, Verlaan M, Kooijman EJ, Poot AJ, Boellaard R, Windhorst AD, van Dongen GA, Vugts DJ, Huisman MC, Beaino W. Performance of nanoScan PET/CT and PET/MR for quantitative imaging of 18F and 89Zr as compared with ex vivo biodistribution in tumor-bearing mice. EJNMMI Res 2021; 11:57. [PMID: 34117946 PMCID: PMC8197690 DOI: 10.1186/s13550-021-00799-2] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2021] [Accepted: 06/02/2021] [Indexed: 12/29/2022] Open
Abstract
INTRODUCTION The assessment of ex vivo biodistribution is the preferred method for quantification of radiotracers biodistribution in preclinical models, but is not in line with current ethics on animal research. PET imaging allows for noninvasive longitudinal evaluation of tracer distribution in the same animals, but systemic comparison with ex vivo biodistribution is lacking. Our aim was to evaluate the potential of preclinical PET imaging for accurate tracer quantification, especially in tumor models. METHODS NEMA NU 4-2008 phantoms were filled with 11C, 68Ga, 18F, or 89Zr solutions and scanned in Mediso nanoPET/CT and PET/MR scanners until decay. N87 tumor-bearing mice were i.v. injected with either [18F]FDG (~ 14 MBq), kept 50 min under anesthesia followed by imaging for 20 min, or with [89Zr]Zr-DFO-NCS-trastuzumab (~ 5 MBq) and imaged 3 days post-injection for 45 min. After PET acquisition, animals were killed and organs of interest were collected and measured in a γ-counter to determine tracer uptake levels. PET data were reconstructed using TeraTomo reconstruction algorithm with attenuation and scatter correction and regions of interest were drawn using Vivoquant software. PET imaging and ex vivo biodistribution were compared using Bland-Altman plots. RESULTS In phantoms, the highest recovery coefficient, thus the smallest partial volume effect, was obtained with 18F for both PET/CT and PET/MR. Recovery was slightly lower for 11C and 89Zr, while the lowest recovery was obtained with 68Ga in both scanners. In vivo, tumor uptake of the 18F- or 89Zr-labeled tracer proved to be similar irrespective whether quantified by either PET/CT and PET/MR or ex vivo biodistribution with average PET/ex vivo ratios of 0.8-0.9 and a deviation of 10% or less. Both methods appeared less congruent in the quantification of tracer uptake in healthy organs such as brain, kidney, and liver, and depended on the organ evaluated and the radionuclide used. CONCLUSIONS Our study suggests that PET quantification of 18F- and 89Zr-labeled tracers is reliable for the evaluation of tumor uptake in preclinical models and a valuable alternative technique for ex vivo biodistribution. However, PET and ex vivo quantification require fully described experimental and analytical procedures for reliability and reproducibility.
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Tuncel H, Boellaard R, Coomans EM, de Vries EFJ, Glaudemans AWJM, Feltes PK, García DV, Verfaillie SCJ, Wolters EE, Sweeney SP, Ryan JM, Ivarsson M, Lynch BA, Schober P, Scheltens P, Schuit RC, Windhorst AD, De Deyn PP, van Berckel BNM, Golla SSV. Kinetics and 28-day test-retest repeatability and reproducibility of [ 11C]UCB-J PET brain imaging. J Cereb Blood Flow Metab 2021; 41:1338-1350. [PMID: 34013797 PMCID: PMC8138337 DOI: 10.1177/0271678x20964248] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/11/2020] [Revised: 08/19/2020] [Accepted: 09/27/2020] [Indexed: 11/18/2022]
Abstract
[11C]UCB-J is a novel radioligand that binds to synaptic vesicle glycoprotein 2A (SV2A). The main objective of this study was to determine the 28-day test-retest repeatability (TRT) of quantitative [11C]UCB-J brain positron emission tomography (PET) imaging in Alzheimer's disease (AD) patients and healthy controls (HCs). Nine HCs and eight AD patients underwent two 60 min dynamic [11C]UCB-J PET scans with arterial sampling with an interval of 28 days. The optimal tracer kinetic model was assessed using the Akaike criteria (AIC). Micro-/macro-parameters such as tracer delivery (K1) and volume of distribution (VT) were estimated using the optimal model. Data were also analysed for simplified reference tissue model (SRTM) with centrum semi-ovale (white matter) as reference region. Based on AIC, both 1T2k_VB and 2T4k_VB described the [11C]UCB-J kinetics equally well. Analysis showed that whole-brain grey matter TRT for VT, DVR and SRTM BPND were -2.2% ± 8.5, 0.4% ± 12.0 and -8.0% ± 10.2, averaged over all subjects. [11C]UCB-J kinetics can be well described by a 1T2k_VB model, and a 60 min scan duration was sufficient to obtain reliable estimates for both plasma input and reference tissue models. TRT for VT, DVR and BPND was <15% (1SD) averaged over all subjects and indicates adequate quantitative repeatability of [11C]UCB-J PET.
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