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Schraven S, Brück R, Rosenhain S, Lemainque T, Heines D, Noormohammadian H, Pabst O, Lederle W, Gremse F, Kiessling F. CT- and MRI-Aided Fluorescence Tomography Reconstructions for Biodistribution Analysis. Invest Radiol 2024; 59:504-512. [PMID: 38038691 DOI: 10.1097/rli.0000000000001052] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/02/2023]
Abstract
OBJECTIVES Optical fluorescence imaging can track the biodistribution of fluorophore-labeled drugs, nanoparticles, and antibodies longitudinally. In hybrid computed tomography-fluorescence tomography (CT-FLT), CT provides the anatomical information to generate scattering and absorption maps supporting a 3-dimensional reconstruction from the raw optical data. However, given the CT's limited soft tissue contrast, fluorescence reconstruction and quantification can be inaccurate and not sufficiently detailed. Magnetic resonance imaging (MRI) can overcome these limitations and extend the options for tissue characterization. Thus, we aimed to establish a hybrid CT-MRI-FLT approach for whole-body imaging and compared it with CT-FLT. MATERIALS AND METHODS The MRI-based hybrid imaging approaches were established first by scanning a water and coconut oil-filled phantom, second by quantifying Cy7 concentrations of inserts in dead mice, and finally by analyzing the biodistribution of AF750-labeled immunoglobulins (IgG, IgA) in living SKH1 mice. Magnetic resonance imaging, acquired with a fat-water-separated mDixon sequence, CT, and FLT were co-registered using markers in the mouse holder frame filled with white petrolatum, which was solid, stable, and visible in both modalities. RESULTS Computed tomography-MRI fusion was confirmed by comparing the segmentation agreement using Dice scores. Phantom segmentations showed good agreement, after correction for gradient linearity distortion and chemical shift. Organ segmentations in dead and living mice revealed adequate agreement for fusion. Marking the mouse holder frame and the successful CT-MRI fusion enabled MRI-FLT as well as CT-MRI-FLT reconstructions. Fluorescence tomography reconstructions supported by CT, MRI, or CT-MRI were comparable in dead mice with 60 pmol fluorescence inserts at different locations. Although standard CT-FLT reconstruction only considered general values for soft tissue, skin, lung, fat, and bone scattering, MRI's more versatile soft tissue contrast enabled the additional consideration of liver, kidneys, and brain. However, this did not change FLT reconstructions and quantifications significantly, whereas for extending scattering maps, it was important to accurately segment the organs and the entire mouse body. The various FLT reconstructions also provided comparable results for the in vivo biodistribution analyses with fluorescent immunoglobulins. However, MRI additionally enabled the visualization of gallbladder, thyroid, and brain. Furthermore, segmentations of liver, spleen, and kidney were more reliable due to better-defined contours than in CT. Therefore, the improved segmentations enabled better assignment of fluorescence signals and more differentiated conclusions with MRI-FLT. CONCLUSIONS Whole-body CT-MRI-FLT was implemented as a novel trimodal imaging approach, which allowed to more accurately assign fluorescence signals, thereby significantly improving pharmacokinetic analyses.
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Affiliation(s)
- Sarah Schraven
- From the Institute for Experimental Molecular Imaging, RWTH Aachen University, Aachen, Germany (S.S., R.B., S.R., T.L., D.H., W.L., F.G., F.K.); Institute of Molecular Medicine, RWTH Aachen University, Aachen, Germany (H.N., O.P.); Gremse-IT GmbH, Aachen, Germany (S.R., F.G.); Department for Diagnostic and Interventional Radiology, RWTH Aachen University, Aachen, Germany (T.L.); Helmholtz Institute for Biomedical Engineering, RWTH Aachen University, Aachen, Germany (F.K.); and Fraunhofer MEVIS, Institute for Medical Image Computing, Aachen, Germany (F.K.)
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Schraven S, Rosenhain S, Brueck R, Wiechmann TM, Pola R, Etrych T, Lederle W, Lammers T, Gremse F, Kiessling F. Dye labeling for optical imaging biases drug carriers' biodistribution and tumor uptake. NANOMEDICINE : NANOTECHNOLOGY, BIOLOGY, AND MEDICINE 2023; 48:102650. [PMID: 36623712 DOI: 10.1016/j.nano.2023.102650] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/08/2022] [Revised: 12/25/2022] [Accepted: 12/27/2022] [Indexed: 01/08/2023]
Abstract
Biodistribution analyses of nanocarriers are often performed with optical imaging. Though dye tags can interact with transporters, e.g., organic anion transporting polypeptides (OATPs), their influence on biodistribution was hardly studied. Therefore, this study compared tumor cell uptake and biodistribution (in A431 tumor-bearing mice) of four near-infrared fluorescent dyes (AF750, IRDye750, Cy7, DY-750) and dye-labeled poly(N-(2-hydroxypropyl)methacrylamide)-based nanocarriers (dye-pHPMAs). Tumor cell uptake of hydrophobic dyes (Cy7, DY-750) was higher than that of hydrophilic dyes (AF750, IRDye750), and was actively mediated but not related to OATPs. Free dyes' elimination depended on their hydrophobicity, and tumor uptake correlated with blood circulation times. Dye-pHPMAs circulated longer and accumulated stronger in tumors than free dyes. Dye labeling significantly influenced nanocarriers' tumor accumulation and biodistribution. Therefore, low-interference dyes and further exploration of dye tags are required to achieve the most unbiased results possible. In our assessment, AF750 and IRDye750 best qualified for labeling hydrophilic nanocarriers.
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Affiliation(s)
- Sarah Schraven
- Institute for Experimental Molecular Imaging, RWTH Aachen University, Forckenbeckstrasse 55, 52074 Aachen, Germany
| | - Stefanie Rosenhain
- Institute for Experimental Molecular Imaging, RWTH Aachen University, Forckenbeckstrasse 55, 52074 Aachen, Germany; Gremse-IT GmbH, Dennewartstrasse 25, 52068 Aachen, Germany
| | - Ramona Brueck
- Institute for Experimental Molecular Imaging, RWTH Aachen University, Forckenbeckstrasse 55, 52074 Aachen, Germany
| | - Tim Marvin Wiechmann
- Institute for Experimental Molecular Imaging, RWTH Aachen University, Forckenbeckstrasse 55, 52074 Aachen, Germany
| | - Robert Pola
- Institute of Macromolecular Chemistry, Czech Academy of Sciences, Heyrovského nám. 2, 162 06 Prague, Czech Republic
| | - Tomáš Etrych
- Institute of Macromolecular Chemistry, Czech Academy of Sciences, Heyrovského nám. 2, 162 06 Prague, Czech Republic
| | - Wiltrud Lederle
- Institute for Experimental Molecular Imaging, RWTH Aachen University, Forckenbeckstrasse 55, 52074 Aachen, Germany
| | - Twan Lammers
- Institute for Experimental Molecular Imaging, RWTH Aachen University, Forckenbeckstrasse 55, 52074 Aachen, Germany
| | - Felix Gremse
- Institute for Experimental Molecular Imaging, RWTH Aachen University, Forckenbeckstrasse 55, 52074 Aachen, Germany; Gremse-IT GmbH, Dennewartstrasse 25, 52068 Aachen, Germany
| | - Fabian Kiessling
- Institute for Experimental Molecular Imaging, RWTH Aachen University, Forckenbeckstrasse 55, 52074 Aachen, Germany; Helmholtz Institute for Biomedical Engineering, RWTH Aachen University, Aachen, Germany; Fraunhofer MEVIS, Institute for Medical Image Computing, Aachen, Germany.
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Man F, Tang J, Swedrowska M, Forbes B, T M de Rosales R. Imaging drug delivery to the lungs: Methods and applications in oncology. Adv Drug Deliv Rev 2023; 192:114641. [PMID: 36509173 PMCID: PMC10227194 DOI: 10.1016/j.addr.2022.114641] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2022] [Revised: 11/25/2022] [Accepted: 11/26/2022] [Indexed: 12/14/2022]
Abstract
Direct delivery to the lung via inhalation is arguably one of the most logical approaches to treat lung cancer using drugs. However, despite significant efforts and investment in this area, this strategy has not progressed in clinical trials. Imaging drug delivery is a powerful tool to understand and develop novel drug delivery strategies. In this review we focus on imaging studies of drug delivery by the inhalation route, to provide a broad overview of the field to date and attempt to better understand the complexities of this route of administration and the significant barriers that it faces, as well as its advantages. We start with a discussion of the specific challenges for drug delivery to the lung via inhalation. We focus on the barriers that have prevented progress of this approach in oncology, as well as the most recent developments in this area. This is followed by a comprehensive overview of the different imaging modalities that are relevant to lung drug delivery, including nuclear imaging, X-ray imaging, magnetic resonance imaging, optical imaging and mass spectrometry imaging. For each of these modalities, examples from the literature where these techniques have been explored are provided. Finally the different applications of these technologies in oncology are discussed, focusing separately on small molecules and nanomedicines. We hope that this comprehensive review will be informative to the field and will guide the future preclinical and clinical development of this promising drug delivery strategy to maximise its therapeutic potential.
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Affiliation(s)
- Francis Man
- School of Cancer & Pharmaceutical Sciences, King's College London, London, SE1 9NH, United Kingdom
| | - Jie Tang
- School of Biomedical Engineering & Imaging Sciences, King's College London, London SE1 7EH, United Kingdom
| | - Magda Swedrowska
- School of Cancer & Pharmaceutical Sciences, King's College London, London, SE1 9NH, United Kingdom
| | - Ben Forbes
- School of Cancer & Pharmaceutical Sciences, King's College London, London, SE1 9NH, United Kingdom
| | - Rafael T M de Rosales
- School of Biomedical Engineering & Imaging Sciences, King's College London, London SE1 7EH, United Kingdom.
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Höltke C, Alsibai W, Grewer M, Stölting M, Geyer C, Eisenblätter M, Wildgruber M, Helfen A. How Different Albumin-Binders Drive Probe Distribution of Fluorescent RGD Mimetics. Front Chem 2021; 9:689850. [PMID: 34504831 PMCID: PMC8421774 DOI: 10.3389/fchem.2021.689850] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2021] [Accepted: 08/09/2021] [Indexed: 11/13/2022] Open
Abstract
The biodistribution of medical imaging probes depends on the chemical nature of the probe and the preferred metabolization and excretion routes. Especially targeted probes, which have to reach a certain (sub)cellular destination, have to be guided to the tissue of interest. Therefore, small molecular probes need to exhibit a well-balanced polarity and lipophilicity to maintain an advantageous bioavailability. Labelled antibodies circulate for several days due to their size. To alter the biodistribution behavior of probes, different strategies have been pursued, including utilizing serum albumin as an inherent transport mechanism for small molecules. We describe here the modification of an existing fluorescent RGD mimetic probe targeted to integrin αvβ3 with three different albumin binding moieties (ABMs): a diphenylcyclohexyl (DPCH) group, a p-iodophenyl butyric acid (IPBA) and a fatty acid (FA) group with the purpose to identify an optimal ABM for molecular imaging applications. All three modifications result in transient albumin binding and a preservation of the target binding capability. Spectrophotometric measurements applying variable amounts of bovine serum albumin (BSA) reveal considerable differences between the compounds concerning their absorption and emission characteristics and hence their BSA binding mode. In vivo the modified probes were investigated in a murine U87MG glioblastoma xenograft model over the course of 1 wk by fluorescence reflectance imaging (FRI) and fluorescence mediated tomography (FMT). While the unmodified probe was excreted rapidly, the albumin-binding probes were accumulating in tumor tissue for at least 5 days. Considerable differences between the three probes in biodistribution and excretion characteristics were proved, with the DPCH-modified probe showing the highest overall signal intensities, while the FA-modified probe exhibits a low but more specific fluorescent signal. In conclusion, the modification of small molecular RGD mimetics with ABMs can precisely fine-tune probe distribution and offers potential for future clinical applications.
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Affiliation(s)
- Carsten Höltke
- Clinic for Radiology, University Hospital Münster, Münster, Germany
| | - Wael Alsibai
- Clinic for Radiology, University Hospital Münster, Münster, Germany
| | - Martin Grewer
- Clinic for Radiology, University Hospital Münster, Münster, Germany
| | - Miriam Stölting
- Clinic for Radiology, University Hospital Münster, Münster, Germany
| | - Christiane Geyer
- Clinic for Radiology, University Hospital Münster, Münster, Germany
| | - Michel Eisenblätter
- Clinic for Radiology, University Hospital Münster, Münster, Germany.,Department of Radiology, University Hospital Freiburg, Freiburg, Germany
| | - Moritz Wildgruber
- Clinic for Radiology, University Hospital Münster, Münster, Germany.,Department of Radiology, University Hospital, LMU Munich, Munich, Germany
| | - Anne Helfen
- Clinic for Radiology, University Hospital Münster, Münster, Germany
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Mixing Matrix-corrected Whole-body Pharmacokinetic Modeling Using Longitudinal Micro-computed Tomography and Fluorescence-mediated Tomography. Mol Imaging Biol 2021; 23:963-974. [PMID: 34231106 PMCID: PMC8578052 DOI: 10.1007/s11307-021-01623-y] [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: 02/23/2021] [Revised: 04/30/2021] [Accepted: 06/06/2021] [Indexed: 10/29/2022]
Abstract
PURPOSE Pharmacokinetic modeling can be applied to quantify the kinetics of fluorescently labeled compounds using longitudinal micro-computed tomography and fluorescence-mediated tomography (μCT-FMT). However, fluorescence blurring from neighboring organs or tissues and the vasculature within tissues impede the accuracy in the estimation of kinetic parameters. Contributions of elimination and retention activities of fluorescent probes inside the kidneys and liver can be hard to distinguish by a kinetic model. This study proposes a deconvolution approach using a mixing matrix to model fluorescence contributions to improve whole-body pharmacokinetic modeling. PROCEDURES In the kinetic model, a mixing matrix was applied to unmix the fluorescence blurring from neighboring tissues and blood vessels and unmix the fluorescence contributions of elimination and retention in the kidney and liver compartments. Accordingly, the kinetic parameters of the hepatobiliary and renal elimination routes and five major retention sites (the kidneys, liver, bone, spleen, and lung) were investigated in simulations and in an in vivo study. In the latter, the pharmacokinetics of four fluorescently labeled compounds (indocyanine green (ICG), HITC-iodide-microbubbles (MB), Cy7-nanogels (NG), and OsteoSense 750 EX (OS)) were evaluated in BALB/c nude mice. RESULTS In the simulations, the corrected modeling resulted in lower relative errors and stronger linear relationships (slopes close to 1) between the estimated and simulated parameters, compared to the uncorrected modeling. For the in vivo study, MB and NG showed significantly higher hepatic retention rates (P<0.05 and P<0.05, respectively), while OS had smaller renal and hepatic retention rates (P<0.01 and P<0.01, respectively). Additionally, the bone retention rate of OS was significantly higher (P<0.01). CONCLUSIONS The mixing matrix correction improves pharmacokinetic modeling and thus enables a more accurate assessment of the biodistribution of fluorescently labeled pharmaceuticals by μCT-FMT.
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Vøls KK, Kjelgaard-Hansen M, Ley CD, Hansen AK, Petersen M. In vivo fluorescence molecular tomography of induced haemarthrosis in haemophilic mice: link between bleeding characteristics and development of bone pathology. BMC Musculoskelet Disord 2020; 21:241. [PMID: 32290832 PMCID: PMC7158129 DOI: 10.1186/s12891-020-03267-5] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/25/2019] [Accepted: 04/03/2020] [Indexed: 12/17/2022] Open
Abstract
Background Haemophilic arthropathy is a chronic and debilitating joint disease caused by recurrent spontaneous joint bleeds in patients with haemophilia. Understanding how characteristics of individual joint bleeds relate to the subsequent development of arthropathy could improve management and prevention of this joint disease. Here, we aimed to explore relations between joint bleed characteristics and development of bone pathology in a mouse model of haemophilic arthropathy by using novel in vivo imaging methodology. Methods We characterised induced knee bleeds in a murine model of haemophilic arthropathy by quantitative in vivo fluorescence molecular tomography (FMT) and by measurements of changes in the diameter of the injured knee. Wild-type mice and non-injured haemophilic mice acted as controls. Development of arthropathy was characterised by post mortem evaluation of bone pathology by micro-CT 14 days after bleed-induction. In an in vitro study, we assessed the effect of blood on the quantification of fluorescent signal with FMT. Results In most injured haemophilic mice, we observed significant loss of trabecular bone, and half of the mice developed pathological bone remodelling. Development of pathological bone remodelling was associated with significantly increased fluorescent signal and diameter of the injured knee just 1 day after induction of the bleed. Further, a correlation between the fluorescent signal 1 day after induction of the bleed and loss of trabecular bone reached borderline significance. In the in vitro study, we found that high concentrations of blood significantly decreased the fluorescent signal. Conclusion Our results add novel insights on the pathogenesis of haemophilic arthropathy and underline the importance of the acute phase of joint bleeds for the subsequent development of arthropathy.
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Affiliation(s)
- K K Vøls
- Global Drug Discovery, Novo Nordisk A/S, Novo Nordisk Park 1, 2760, Maaloev, Denmark. .,Veterinary and Animal Sciences, University of Copenhagen, Frederiksberg, Denmark.
| | - M Kjelgaard-Hansen
- Veterinary Clinical Sciences, University of Copenhagen, Frederiksberg, Denmark
| | - C D Ley
- Global Drug Discovery, Novo Nordisk A/S, Novo Nordisk Park 1, 2760, Maaloev, Denmark
| | - A K Hansen
- Veterinary and Animal Sciences, University of Copenhagen, Frederiksberg, Denmark
| | - M Petersen
- Global Drug Discovery, Novo Nordisk A/S, Novo Nordisk Park 1, 2760, Maaloev, Denmark
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Mannheim JG, Kara F, Doorduin J, Fuchs K, Reischl G, Liang S, Verhoye M, Gremse F, Mezzanotte L, Huisman MC. Standardization of Small Animal Imaging-Current Status and Future Prospects. Mol Imaging Biol 2019; 20:716-731. [PMID: 28971332 DOI: 10.1007/s11307-017-1126-2] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
The benefit of small animal imaging is directly linked to the validity and reliability of the collected data. If the data (regardless of the modality used) are not reproducible and/or reliable, then the outcome of the data is rather questionable. Therefore, standardization of the use of small animal imaging equipment, as well as of animal handling in general, is of paramount importance. In a recent paper, guidance for efficient small animal imaging quality control was offered and discussed, among others, the use of phantoms in setting up a quality control program (Osborne et al. 2016). The same phantoms can be used to standardize image quality parameters for multi-center studies or multi-scanners within center studies. In animal experiments, the additional complexity due to animal handling needs to be addressed to ensure standardized imaging procedures. In this review, we will address the current status of standardization in preclinical imaging, as well as potential benefits from increased levels of standardization.
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Affiliation(s)
- Julia G Mannheim
- Werner Siemens Imaging Center, Department of Preclinical Imaging and Radiopharmacy, Eberhard Karls University Tuebingen, Roentgenweg 13, 72076, Tuebingen, Germany.
| | - Firat Kara
- Bio-Imaging Lab, University of Antwerp, Antwerp, Belgium
| | - Janine Doorduin
- Department of Nuclear Medicine and Molecular Imaging, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands
| | - Kerstin Fuchs
- Werner Siemens Imaging Center, Department of Preclinical Imaging and Radiopharmacy, Eberhard Karls University Tuebingen, Roentgenweg 13, 72076, Tuebingen, Germany
| | - Gerald Reischl
- Werner Siemens Imaging Center, Department of Preclinical Imaging and Radiopharmacy, Eberhard Karls University Tuebingen, Roentgenweg 13, 72076, Tuebingen, Germany
| | - Sayuan Liang
- Bio-Imaging Lab, University of Antwerp, Antwerp, Belgium
| | | | - Felix Gremse
- Institute for Experimental Molecular Imaging, RWTH Aachen University Clinic, Aachen, Germany
| | - Laura Mezzanotte
- Optical Molecular Imaging, Department of Radiology, Erasmus Medical Center, Rotterdam, The Netherlands
| | - Marc C Huisman
- Department of Radiology and Nuclear Medicine, VU University Medical Center, Amsterdam, The Netherlands
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Hage C, Gremse F, Griessinger CM, Maurer A, Hoffmann SH, Osl F, Pichler BJ, Kiessling F, Scheuer W, Pöschinger T. Comparison of the Accuracy of FMT/CT and PET/MRI for the Assessment of Antibody Biodistribution in Squamous Cell Carcinoma Xenografts. J Nucl Med 2017; 59:44-50. [DOI: 10.2967/jnumed.117.197178] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2017] [Accepted: 07/25/2017] [Indexed: 11/16/2022] Open
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Rawashdeh WA, Zuo S, Melle A, Appold L, Koletnik S, Tsvetkova Y, Beztsinna N, Pich A, Lammers T, Kiessling F, Gremse F. Noninvasive Assessment of Elimination and Retention using CT-FMT and Kinetic Whole-body Modeling. Am J Cancer Res 2017; 7:1499-1510. [PMID: 28529633 PMCID: PMC5436509 DOI: 10.7150/thno.17263] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2016] [Accepted: 01/16/2017] [Indexed: 11/25/2022] Open
Abstract
Fluorescence-mediated tomography (FMT) is a quantitative three-dimensional imaging technique for preclinical research applications. The combination with micro-computed tomography (µCT) enables improved reconstruction and analysis. The aim of this study is to assess the potential of µCT-FMT and kinetic modeling to determine elimination and retention of typical model drugs and drug delivery systems. We selected four fluorescent probes with different but well-known biodistribution and elimination routes: Indocyanine green (ICG), hydroxyapatite-binding OsteoSense (OS), biodegradable nanogels (NG) and microbubbles (MB). µCT-FMT scans were performed in twenty BALB/c nude mice (5 per group) at 0.25, 2, 4, 8, 24, 48 and 72 h after intravenous injection. Longitudinal organ curves were determined using interactive organ segmentation software and a pharmacokinetic whole-body model was implemented and applied to compute physiological parameters describing elimination and retention. ICG demonstrated high initial hepatic uptake which decreased rapidly while intestinal accumulation appeared for around 8 hours which is in line with the known direct uptake by hepatocytes followed by hepatobiliary elimination. Complete clearance from the body was observed at 48 h. NG showed similar but slower hepatobiliary elimination because these nanoparticles require degradation before elimination can take place. OS was strongly located in the bones in addition to high signal in the bladder at 0.25 h indicating fast renal excretion. MB showed longest retention in liver and spleen and low signal in the kidneys likely caused by renal elimination or retention of fragments. Furthermore, probe retention was found in liver (MB, NG and OS), spleen (MB) and kidneys (MB and NG) at 72 h which was confirmed by ex vivo data. The kinetic model enabled robust extraction of physiological parameters from the organ curves. In summary, µCT-FMT and kinetic modeling enable differentiation of hepatobiliary and renal elimination routes and allow for the noninvasive assessment of retention sites in relevant organs including liver, kidney, bone and spleen.
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