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Leach BI, Lister D, Adams SR, Bykowski J, Schwartz AB, McConville P, Dimant H, Ahrens ET. Cryo-Fluorescence Tomography as a Tool for Visualizing Whole-Body Inflammation Using Perfluorocarbon Nanoemulsion Tracers. Mol Imaging Biol 2024:10.1007/s11307-024-01926-w. [PMID: 39023693 DOI: 10.1007/s11307-024-01926-w] [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: 10/30/2023] [Revised: 05/30/2024] [Accepted: 06/03/2024] [Indexed: 07/20/2024]
Abstract
PURPOSE We explore the use of intravenously delivered fluorescent perfluorocarbon (PFC) nanoemulsion tracers and multi-spectral cryo-fluorescence tomography (CFT) for whole-body tracer imaging in murine inflammation models. CFT is an emerging technique that provides high-resolution, three-dimensional mapping of probe localization in intact animals and tissue samples, enabling unbiased validation of probe biodistribution and minimizes reliance on laborious histological methods employing discrete tissue panels, where disseminated populations of PFC-labeled cells may be overlooked. This methodology can be used to streamline the development of new generations of non-invasive, cellular-molecular imaging probes for in vivo imaging. PROCEDURES Mixtures of nanoemulsions with different fluorescent emission wavelengths were administered intravenously to naïve mice and models of acute inflammation, colitis, and solid tumor. Mice were euthanized 24 h post-injection, frozen en bloc, and imaged at high resolution (~ 50 µm voxels) using CFT at multiple wavelengths. RESULTS PFC nanoemulsions were visualized using CFT within tissues of the reticuloendothelial system and inflammatory lesions, consistent with immune cell (macrophage) labeling, as previously reported in in vivo magnetic resonance and nuclear imaging studies. The CFT signals show pronounced differences among fluorescence wavelengths and tissues, presumably due to autofluorescence, differential fluorescence quenching, and scattering of incident and emitted light. CONCLUSIONS CFT is an effective and complementary methodology to in vivo imaging for validating PFC nanoemulsion biodistribution at high spatial localization, bridging the resolution gap between in vivo imaging and histology.
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Affiliation(s)
- Benjamin I Leach
- Department of Radiology, University of California, San Diego, La Jolla, CA, 92093, USA
| | | | - Stephen R Adams
- Department of Pharmacology, University of California, San Diego, La Jolla, CA, 92093, USA
| | - Julie Bykowski
- Department of Radiology, University of California, San Diego, La Jolla, CA, 92093, USA
| | - Amy B Schwartz
- Department of Radiology, University of California, San Diego, La Jolla, CA, 92093, USA
| | | | | | - Eric T Ahrens
- Department of Radiology, University of California, San Diego, La Jolla, CA, 92093, USA.
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Yang H, Howerton B, Brown L, Izumi T, Cheek D, Brandon JA, Marti F, Gedaly R, Adatorwovor R, Chapelin F. Magnetic Resonance Imaging of Macrophage Response to Radiation Therapy. Cancers (Basel) 2023; 15:5874. [PMID: 38136418 PMCID: PMC10742077 DOI: 10.3390/cancers15245874] [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: 09/30/2023] [Revised: 12/01/2023] [Accepted: 12/14/2023] [Indexed: 12/24/2023] Open
Abstract
BACKGROUND Magnetic resonance imaging (MRI) is a non-invasive imaging modality which, in conjunction with biopsies, provide a qualitative assessment of tumor response to treatment. Intravenous injection of contrast agents such as fluorine (19F) nanoemulsions labels systemic macrophages, which can, then, be tracked in real time with MRI. This method can provide quantifiable insights into the behavior of tumor-associated macrophages (TAMs) in the tumor microenvironment and macrophage recruitment during therapy. METHODS Female mice received mammary fat pad injections of murine breast or colon cancer cell lines. The mice then received an intravenous 19F nanoemulsion injection, followed by a baseline 19F MRI. For each cancer model, half of the mice then received 8 Gy of localized radiation therapy (RT), while others remained untreated. The mice were monitored for two weeks for tumor growth and 9F signal using MRI. RESULTS Across both cohorts, the RT-treated groups presented significant tumor growth reduction or arrest, contrary to the untreated groups. Similarly, the fluorine signal in treated groups increased significantly as early as four days post therapy. The fluorine signal change correlated to tumor volumes irrespective of time. CONCLUSION These results demonstrate the potential of 19F MRI to non-invasively track macrophages during radiation therapy and its prognostic value with regard to tumor growth.
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Affiliation(s)
- Harrison Yang
- F. Joseph Halcomb III, M.D. Department of Biomedical Engineering, University of Kentucky, Lexington, KY 40506, USA; (H.Y.); (L.B.)
| | - Brock Howerton
- Shu Chien-Gene Lay Department of Bioengineering, University of California San Diego, La Jolla, CA 92093, USA;
| | - Logan Brown
- F. Joseph Halcomb III, M.D. Department of Biomedical Engineering, University of Kentucky, Lexington, KY 40506, USA; (H.Y.); (L.B.)
| | - Tadahide Izumi
- Lucille Parker Markey Cancer Center, University of Kentucky, Lexington, KY 40536, USA; (T.I.); (F.M.); (R.G.)
- Department of Toxicology and Cancer Biology, University of Kentucky, Lexington, KY 40536, USA
| | - Dennis Cheek
- Department of Radiation Medicine, University of Kentucky, Lexington, KY 40536, USA;
| | - J. Anthony Brandon
- Sanders Brown Center on Aging, University of Kentucky, Lexington, KY 40508, USA;
| | - Francesc Marti
- Lucille Parker Markey Cancer Center, University of Kentucky, Lexington, KY 40536, USA; (T.I.); (F.M.); (R.G.)
- Department of Surgery, Transplant Division, University of Kentucky, Lexington, KY 40506, USA
| | - Roberto Gedaly
- Lucille Parker Markey Cancer Center, University of Kentucky, Lexington, KY 40536, USA; (T.I.); (F.M.); (R.G.)
- Department of Surgery, Transplant Division, University of Kentucky, Lexington, KY 40506, USA
| | - Reuben Adatorwovor
- Department of Biostatistics, University of Kentucky, Lexington, KY 40536, USA;
| | - Fanny Chapelin
- Shu Chien-Gene Lay Department of Bioengineering, University of California San Diego, La Jolla, CA 92093, USA;
- Department of Radiology, University of California San Diego, La Jolla, CA 92093, USA
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Flocke V, Temme S, Bouvain P, Grandoch M, Flögel U. Noninvasive assessment of metabolic turnover during inflammation by in vivo deuterium magnetic resonance spectroscopy. Front Immunol 2023; 14:1258027. [PMID: 37841266 PMCID: PMC10568178 DOI: 10.3389/fimmu.2023.1258027] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2023] [Accepted: 09/11/2023] [Indexed: 10/17/2023] Open
Abstract
Background Inflammation and metabolism exhibit a complex interplay, where inflammation influences metabolic pathways, and in turn, metabolism shapes the quality of immune responses. Here, glucose turnover is of special interest, as proinflammatory immune cells mainly utilize glycolysis to meet their energy needs. Noninvasive approaches to monitor both processes would help elucidate this interwoven relationship to identify new therapeutic targets and diagnostic opportunities. Methods For induction of defined inflammatory hotspots, LPS-doped Matrigel plugs were implanted into the neck of C57BL/6J mice. Subsequently, 1H/19F magnetic resonance imaging (MRI) was used to track the recruitment of 19F-loaded immune cells to the inflammatory focus and deuterium (2H) magnetic resonance spectroscopy (MRS) was used to monitor the metabolic fate of [6,6-2H2]glucose within the affected tissue. Histology and flow cytometry were used to validate the in vivo data. Results After plug implantation and intravenous administration of the 19F-containing contrast agent, 1H/19F MRI confirmed the infiltration of 19F-labeled immune cells into LPS-doped plugs while no 19F signal was observed in PBS-containing control plugs. Identification of the inflammatory focus was followed by i.p. bolus injection of deuterated glucose and continuous 2H MRS. Inflammation-induced alterations in metabolic fluxes could be tracked with an excellent temporal resolution of 2 min up to approximately 60 min after injection and demonstrated a more anaerobic glucose utilization in the initial phase of immune cell recruitment. Conclusion 1H/2H/19F MRI/MRS was successfully employed for noninvasive monitoring of metabolic alterations in an inflammatory environment, paving the way for simultaneous in vivo registration of immunometabolic data in basic research and patients.
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Affiliation(s)
- Vera Flocke
- Experimental Cardiovascular Imaging, Institute for Molecular Cardiology, Heinrich Heine University Düsseldorf, Düsseldorf, Germany
| | - Sebastian Temme
- Department of Anaesthesiology, University Hospital Düsseldorf, Düsseldorf, Germany
- University Hospital Düsseldorf, Cardiovascular Research Institute Düsseldorf (CARID), Düsseldorf, Germany
| | - Pascal Bouvain
- Experimental Cardiovascular Imaging, Institute for Molecular Cardiology, Heinrich Heine University Düsseldorf, Düsseldorf, Germany
| | - Maria Grandoch
- University Hospital Düsseldorf, Cardiovascular Research Institute Düsseldorf (CARID), Düsseldorf, Germany
- Institute for Translational Pharmacology, Heinrich Heine University Düsseldorf, Düsseldorf, Germany
| | - Ulrich Flögel
- Experimental Cardiovascular Imaging, Institute for Molecular Cardiology, Heinrich Heine University Düsseldorf, Düsseldorf, Germany
- University Hospital Düsseldorf, Cardiovascular Research Institute Düsseldorf (CARID), Düsseldorf, Germany
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