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Mannes PZ, Barnes CE, Latoche JD, Day KE, Nedrow JR, Lee JS, Tavakoli S. 2-deoxy-2-[ 18F]fluoro-D-glucose Positron Emission Tomography to Monitor Lung Inflammation and Therapeutic Response to Dexamethasone in a Murine Model of Acute Lung Injury. Mol Imaging Biol 2023; 25:681-691. [PMID: 36941514 PMCID: PMC10027262 DOI: 10.1007/s11307-023-01813-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2022] [Revised: 01/30/2023] [Accepted: 03/07/2023] [Indexed: 03/23/2023]
Abstract
PURPOSE To image inflammation and monitor therapeutic response to anti-inflammatory intervention using 2-deoxy-2-[18F]fluoro-D-glucose ([18F]FDG) positron emission tomography (PET) in a preclinical model of acute lung injury (ALI). PROCEDURES Mice were intratracheally administered lipopolysaccharide (LPS, 2.5 mg/kg) to induce ALI or phosphate-buffered saline as the vehicle control. A subset of mice in the ALI group received two intraperitoneal doses of dexamethasone 1 and 24 h after LPS. [18F]FDG PET/CT was performed 2 days after the induction of ALI. [18F]FDG uptake in the lungs was quantified by PET (%ID/mLmean and standardized uptake value (SUVmean)) and ex vivo γ-counting (%ID/g). The severity of lung inflammation was determined by quantifying the protein level of inflammatory cytokines/chemokines and the activity of neutrophil elastase and glycolytic enzymes. In separate groups of mice, flow cytometry was performed to estimate the contribution of individual immune cell types to the total pulmonary inflammatory cell burden under different treatment conditions. RESULTS Lung uptake of [18F]FDG was significantly increased during LPS-induced ALI, and a decreased [18F]FDG uptake was observed following dexamethasone treatment to an intermediate level between that of LPS-treated and control mice. Protein expression of inflammatory biomarkers and the activity of neutrophil elastase and glycolytic enzymes were increased in the lungs of LPS-treated mice versus those of control mice, and correlated with [18F]FDG uptake. Furthermore, dexamethasone-induced decreases in cytokine/chemokine protein levels and enzyme activities correlated with [18F]FDG uptake. Neutrophils were the most abundant cells in LPS-induced ALI, and the pattern of total cell burden during ALI with or without dexamethasone therapy mirrored that of [18F]FDG uptake. CONCLUSIONS [18F]FDG PET noninvasively detects lung inflammation in ALI and its response to anti-inflammatory therapy in a preclinical model. However, high [18F]FDG uptake by bone, brown fat, and myocardium remains a technical limitation for quantification of [18F]FDG in the lungs.
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Affiliation(s)
- Philip Z Mannes
- Department of Radiology, University of Pittsburgh, Pittsburgh, PA, USA
- Medical Scientist Training Program, University of Pittsburgh, Pittsburgh, PA, USA
| | - Clayton E Barnes
- Department of Radiology, University of Pittsburgh, Pittsburgh, PA, USA
| | - Joseph D Latoche
- Department of Medicine, University of Pittsburgh, Pittsburgh, PA, USA
| | - Kathryn E Day
- Department of Medicine, University of Pittsburgh, Pittsburgh, PA, USA
| | - Jessie R Nedrow
- Department of Radiology, University of Pittsburgh, Pittsburgh, PA, USA
- Department of Medicine, University of Pittsburgh, Pittsburgh, PA, USA
| | - Janet S Lee
- Division of Pulmonary, Allergy, and Critical Care Medicine, Department of Medicine, University of Pittsburgh, Pittsburgh, PA, USA
| | - Sina Tavakoli
- Department of Radiology, University of Pittsburgh, Pittsburgh, PA, USA.
- Department of Medicine, University of Pittsburgh, Pittsburgh, PA, USA.
- Heart, Lung, Blood, and Vascular Medicine Institute, University of Pittsburgh Medical Center, Pittsburgh, PA, USA.
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Gulhane AV, Chen DL. Overview of positron emission tomography in functional imaging of the lungs for diffuse lung diseases. Br J Radiol 2022; 95:20210824. [PMID: 34752146 PMCID: PMC9153708 DOI: 10.1259/bjr.20210824] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Positron emission tomography (PET) is a quantitative molecular imaging modality increasingly used to study pulmonary disease processes and drug effects on those processes. The wide range of drugs and other entities that can be radiolabeled to study molecularly targeted processes is a major strength of PET, thus providing a noninvasive approach for obtaining molecular phenotyping information. The use of PET to monitor disease progression and treatment outcomes in DLD has been limited in clinical practice, with most of such applications occurring in the context of research investigations under clinical trials. Given the high costs and failure rates for lung drug development efforts, molecular imaging lung biomarkers are needed not only to aid these efforts but also to improve clinical characterization of these diseases beyond canonical anatomic classifications based on computed tomography. The purpose of this review article is to provide an overview of PET applications in characterizing lung disease, focusing on novel tracers that are in clinical development for DLD molecular phenotyping, and briefly address considerations for accurately quantifying lung PET signals.
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Affiliation(s)
- Avanti V Gulhane
- Department of Radiology, University of Washington School of Medicine, Seattle, United States
| | - Delphine L Chen
- Department of Radiology, University of Washington School of Medicine, Seattle, United States
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HaileMariam M, Yu Y, Singh H, Teklu T, Wondale B, Worku A, Zewude A, Mounaud S, Tsitrin T, Legesse M, Gobena A, Pieper R. Protein and Microbial Biomarkers in Sputum Discern Acute and Latent Tuberculosis in Investigation of Pastoral Ethiopian Cohort. Front Cell Infect Microbiol 2021; 11:595554. [PMID: 34150670 PMCID: PMC8212885 DOI: 10.3389/fcimb.2021.595554] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2020] [Accepted: 03/22/2021] [Indexed: 01/01/2023] Open
Abstract
Differential diagnosis of tuberculosis (TB) and latent TB infection (LTBI) remains a public health priority in high TB burden countries. Pulmonary TB is diagnosed by sputum smear microscopy, chest X-rays, and PCR tests for distinct Mycobacterium tuberculosis (Mtb) genes. Clinical tests to diagnose LTBI rely on immune cell stimulation in blood plasma with TB-specific antigens followed by measurements of interferon-γ concentrations. The latter is an important cytokine for cellular immune responses against Mtb in infected lung tissues. Sputum smear microscopy and chest X-rays are not sufficiently sensitive while both PCR and interferon-γ release assays are expensive. Alternative biomarkers for the development of diagnostic tests to discern TB disease states are desirable. This study's objective was to discover sputum diagnostic biomarker candidates from the analysis of samples from 161 human subjects including TB patients, individuals with LTBI, negative community controls (NCC) from the province South Omo, a pastoral region in Ethiopia. We analyzed 16S rRNA gene-based bacterial taxonomies and proteomic profiles. The sputum microbiota did not reveal statistically significant differences in α-diversity comparing the cohorts. The genus Mycobacterium, representing Mtb, was only identified for the TB group which also featured reduced abundance of the genus Rothia in comparison with the LTBI and NCC groups. Rothia is a respiratory tract commensal and may be sensitive to the inflammatory milieu generated by infection with Mtb. Proteomic data supported innate immune responses against the pathogen in subjects with pulmonary TB. Ferritin, an iron storage protein released by damaged host cells, was markedly increased in abundance in TB sputum compared to the LTBI and NCC groups, along with the α-1-acid glycoproteins ORM1 and ORM2. These proteins are acute phase reactants and inhibit excessive neutrophil activation. Proteomic data highlight the effector roles of neutrophils in the anti-Mtb response which was not observed for LTBI cases. Less abundant in the sputum of the LTBI group, compared to the NCC group, were two immunomodulatory proteins, mitochondrial TSPO and the extracellular ribonuclease T2. If validated, these proteins are of interest as new biomarkers for diagnosis of LTBI.
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Affiliation(s)
- Milkessa HaileMariam
- Aklilu Lemma Institute of Pathobiology, Addis Ababa University, Addis Ababa, Ethiopia
| | - Yanbao Yu
- J. Craig Venter Institute, Rockville, MD, United States
| | - Harinder Singh
- J. Craig Venter Institute, Rockville, MD, United States
| | - Takele Teklu
- Aklilu Lemma Institute of Pathobiology, Addis Ababa University, Addis Ababa, Ethiopia
- Department of Immunology and Molecular Biology, University of Gondar, Gondar, Ethiopia
| | - Biniam Wondale
- Aklilu Lemma Institute of Pathobiology, Addis Ababa University, Addis Ababa, Ethiopia
- Department of Biology, Arba Minch University, Arba Minch, Ethiopia
| | - Adane Worku
- Aklilu Lemma Institute of Pathobiology, Addis Ababa University, Addis Ababa, Ethiopia
| | - Aboma Zewude
- Aklilu Lemma Institute of Pathobiology, Addis Ababa University, Addis Ababa, Ethiopia
| | | | - Tamara Tsitrin
- J. Craig Venter Institute, Rockville, MD, United States
| | - Mengistu Legesse
- Aklilu Lemma Institute of Pathobiology, Addis Ababa University, Addis Ababa, Ethiopia
| | - Ameni Gobena
- Aklilu Lemma Institute of Pathobiology, Addis Ababa University, Addis Ababa, Ethiopia
| | - Rembert Pieper
- J. Craig Venter Institute, Rockville, MD, United States
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Chang CW, Chiu CH, Lin MH, Wu HM, Yu TH, Wang PY, Kuo YY, Huang YY, Shiue CY, Huang WS, Yeh SHH. GMP-compliant fully automated radiosynthesis of [ 18F]FEPPA for PET/MRI imaging of regional brain TSPO expression. EJNMMI Res 2021; 11:26. [PMID: 33725191 PMCID: PMC7966678 DOI: 10.1186/s13550-021-00768-9] [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: 12/02/2020] [Accepted: 03/03/2021] [Indexed: 12/02/2022] Open
Abstract
Background Expression of translocator protein (TSPO) on the outer mitochondrial membrane of activated microglia is strongly associated with neuroinflammation. The second-generation PET ligand [18F]FEPPA specifically binds TSPO to enable in vivo visualization and quantification of neuroinflammation. We optimized a fully automated radiosynthesis method and evaluated the utility of [18F]FEPPA, the second-generation PET ligand specifically binds TSPO, in a mouse model of systemic LPS challenge to detect TSPO-associated signals of central and peripheral inflammation. In vivo dynamic PET/MR imaging was performed in LPS-induced and control mice after [18F]FEPPA administration. The relationship between the [18F]FEPPA signal and the dose of LPS was assessed. The cytokine levels (i.e., TNF-α, Il-1β, Il-6) in LPS-induced mice were measured by RT-PCR. Standard uptake value (SUV), total volume of distribution (VT) and area under the curve (AUC) were determined based on the metabolite-uncorrected plasma input function. Western blotting and immunostaining were used to measure TSPO expression in the brain. Results The fully automated [18F]FEPPA radiosynthesis produced an uncorrected radiochemical yield of 30 ± 2% within 80 min, with a radiochemical purity greater than 99% and specific activity of 148.9‒216.8 GBq/µmol. Significant differences were observed in the brain after [18F]FEPPA administration: SUV, VT and AUC were 1.61 ± 0.1, 1.25 ± 0.12 and 1.58 ± 0.09-fold higher in LPS-injected mice than controls. TNF-α, Il-1β and Il-6 mRNA levels were also elevated in the brains of LPS-injected mice. Western blotting revealed TSPO (p < 0.05) and Iba-1 (p < 0.01) were upregulated in the brain after LPS administration. In LPS-injected mice, TSPO immunoactivity colocalized with Iba-1 in the cerebrum and TSPO was significantly overexpressed in the hippocampus and cerebellum. The peripheral organs (heart, lung) of LPS-injected mice had higher [18F]FEPPA signal-to-noise ratios than control mice. Conclusions Based on the current data on ligand specificity and selectivity in central tissues using 7 T PET/MR imaging, we demonstrate that [18F]FEPPA accumulations significant increased in the specific brain regions of systemic LPS-induced neuroinflammation (5 mg/kg). Future investigations are needed to determine the sensitivity of [18F]FEPPA as a biomarker of neuroinflammation as well as the correlation between the PET signal intensity and the expression levels of TSPO. Supplementary Information The online version contains supplementary material available at 10.1186/s13550-021-00768-9.
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Affiliation(s)
- Chi-Wei Chang
- Department of Nuclear Medicine, Taipei Veterans General Hospital, Taipei, Taiwan.,Department of Medical Imaging and Radiological Technology, The Institute of Radiological Sciences, Tzu Chi University of Science and Technology, Hualien City, Taiwan.,Department of Biomedical Engineering and Environmental Sciences, National Tsinghua University, Hsinchu, Taiwan
| | - Chuang-Hsin Chiu
- Department of Nuclear Medicine, Tri-Service General Hospital, Taipei, Taiwan
| | - Ming-Hsien Lin
- Department of Nuclear Medicine, Cheng Hsin General Hospital, Taipei, Taiwan.,Department of Nuclear Medicine, Camillian Saint Mary's Hospital Luodong, Yilan, Taiwan
| | - Hung-Ming Wu
- Department of Neurology, Changhua Christian Hospital, Changhua, Taiwan
| | - Tsung-Hsun Yu
- Brain Research Center, National Yang Ming Chiao Tung University, No. 155, Sec. 2, Linong Street, Taipei, 112, Taiwan
| | - Pao-Yeh Wang
- Brain Research Center, National Yang Ming Chiao Tung University, No. 155, Sec. 2, Linong Street, Taipei, 112, Taiwan
| | - Yu-Yeh Kuo
- Brain Research Center, National Yang Ming Chiao Tung University, No. 155, Sec. 2, Linong Street, Taipei, 112, Taiwan
| | - Ya-Yao Huang
- PET Center, Department of Nuclear Medicine, National Taiwan University Hospital, Taipei, 100, Taiwan.,Molecular Imaging Center, National Taiwan University, Taipei, Taiwan
| | - Chyng-Yann Shiue
- Molecular Imaging Center, National Taiwan University, Taipei, Taiwan.,PET Center, Department of Nuclear Medicine, Tri-Service General Hospital, Taipei, Taiwan
| | - Wen-Sheng Huang
- Department of Nuclear Medicine, Taipei Veterans General Hospital, Taipei, Taiwan.,Department of Nuclear Medicine, Taipei Medical University Hospital, Taipei, Taiwan
| | - Skye Hsin-Hsien Yeh
- Brain Research Center, National Yang Ming Chiao Tung University, No. 155, Sec. 2, Linong Street, Taipei, 112, Taiwan.
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5
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Adhikari A, Singh P, Mahar KS, Adhikari M, Adhikari B, Zhang MR, Tiwari AK. Mapping of Translocator Protein (18 kDa) in Peripheral Sterile Inflammatory Disease and Cancer through PET Imaging. Mol Pharm 2021; 18:1507-1529. [PMID: 33645995 DOI: 10.1021/acs.molpharmaceut.1c00002] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Positron emission tomography (PET) imaging of the translocator 18 kDa protein (TSPO) with radioligands has become an effective means of research in peripheral inflammatory conditions that occur in many diseases and cancers. The peripheral sterile inflammatory diseases (PSIDs) are associated with a diverse group of disorders that comprises numerous enduring insults including the cardiovascular, respiratory, gastrointestinal, or musculoskeletal system. TSPO has recently been introduced as a potential biomarker for peripheral sterile inflammatory diseases (PSIDs). The major critical issue related to PSIDs is its timely characterization and localization of inflammatory foci for proper therapy of patients. As an alternative to metabolic imaging, protein imaging expressed on immune cells after activation is of great importance. The five transmembrane domain translocator protein-18 kDa (TSPO) is upregulated on the mitochondrial cell surface of macrophages during inflammation, serving as a potential ligand for PET tracers. Additionally, the overexpressed TSPO protein has been positively correlated with various tumor malignancies. In view of the association of escalated TSPO expression in both disease conditions, it is an immensely important biomarker for PET imaging in oncology and PSIDs. In this review, we summarize the most outstanding advances on TSPO-targeted PSIDs and cancer in the development of TSPO ligands as a potential diagnostic tool, specifically discussing the last five years.
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Affiliation(s)
- Anupriya Adhikari
- Department of Chemistry, Babasaheb Bhimrao Ambedkar University, (A Central University), Lucknow, Uttar Pradesh 226025, India
| | - Priya Singh
- Department of Chemistry, Babasaheb Bhimrao Ambedkar University, A Central University, Lucknow, Uttar Pradesh 226025, India
| | - Kamalesh S Mahar
- Birbal Sahni Institute of Palaeosciences, Lucknow, Uttar Pradesh 226007, India
| | - Manish Adhikari
- The George Washington University, Washington, D.C. 20052, United States
| | - Bhawana Adhikari
- Plasma Bio-science Research Center, Kwangwoon University, Seoul 01897, South Korea
| | - Ming-Rong Zhang
- Department of Advanced Nuclear Medicine Sciences, National Institute of Radiological Sciences, National Institutes for Quantum and Radiological Science and Technology, Chiba 263-8555, Japan
| | - Anjani Kumar Tiwari
- Department of Chemistry, Babasaheb Bhimrao Ambedkar University, (A Central University), Lucknow, Uttar Pradesh 226025, India
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Vass L, Fisk M, Lee S, Wilson FJ, Cheriyan J, Wilkinson I. Advances in PET to assess pulmonary inflammation: A systematic review. Eur J Radiol 2020; 130:109182. [DOI: 10.1016/j.ejrad.2020.109182] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2020] [Revised: 05/27/2020] [Accepted: 07/07/2020] [Indexed: 12/12/2022]
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Keller T, López-Picón FR, Krzyczmonik A, Forsback S, Kirjavainen AK, Takkinen JS, Alzghool O, Rajander J, Teperi S, Cacheux F, Damont A, Dollé F, Rinne JO, Solin O, Haaparanta-Solin M. [ 18F]F-DPA for the detection of activated microglia in a mouse model of Alzheimer's disease. Nucl Med Biol 2018; 67:1-9. [PMID: 30317069 DOI: 10.1016/j.nucmedbio.2018.09.001] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2018] [Revised: 09/03/2018] [Accepted: 09/23/2018] [Indexed: 02/06/2023]
Abstract
INTRODUCTION Neuroinflammation is associated with several neurological disorders, including Alzheimer's disease (AD). The translocator protein 18 kDa (TSPO), due to its overexpression during microglial activation and relatively low levels in the brain under normal neurophysiological conditions, is commonly used as an in vivo biomarker for neuroinflammation. Reported here is the preclinical evaluation of [18F]F-DPA, a promising new TSPO-specific radioligand, as a tool for the detection of activated microglia at different ages in the APP/PS1-21 mouse model of AD and a blocking study to determine the specificity of the tracer. METHODS [18F]F-DPA was synthesised by the previously reported electrophilic 18F-fluorination methodology. In vivo PET and ex vivo brain autoradiography were used to observe the tracer distribution in the brains of APP/PS1-21 and wildtype mice at different ages (4.5-24 months). The biodistribution and degree of metabolism of [18F]F-DPA were analysed and the specificity of [18F]F-DPA for its target was determined by pre-treatment with PK11195. RESULTS The in vivo PET imaging and ex vivo brain autoradiography data showed that [18F]F-DPA uptake in the brains of the transgenic animals increased with age, however, there was a drop in the tracer uptake at 19 mo. Despite the slight increase in [18F]F-DPA uptake with age in healthy animal brains, significant differences between wildtype and transgenic animals were seen in vivo at 9 months and ex vivo already at 4.5 months. The specificity study demonstrated that PK11195 can be used to significantly block [18F]F-DPA uptake in all the brain regions studied. CONCLUSIONS In vivo time activity curves plateaued at approximately 20-40 min suggesting that this is the optimal imaging time. Significant differences in vivo are seen at 9 and 12 mo. Due to the higher resolution, ex vivo autoradiography with [18F]F-DPA can be used to visualise activated microglia at an early stage of AD pathology.
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Affiliation(s)
- Thomas Keller
- Radiopharmaceutical Chemistry Laboratory, Turku PET Centre, University of Turku, Finland.
| | - Francisco R López-Picón
- PET Preclinical Imaging Laboratory, Turku PET Centre, University of Turku, Finland; MediCity Research Laboratory, University of Turku, Finland
| | - Anna Krzyczmonik
- Radiopharmaceutical Chemistry Laboratory, Turku PET Centre, University of Turku, Finland
| | - Sarita Forsback
- Radiopharmaceutical Chemistry Laboratory, Turku PET Centre, University of Turku, Finland; Department of Chemistry, University of Turku, Finland
| | - Anna K Kirjavainen
- Radiopharmaceutical Chemistry Laboratory, Turku PET Centre, University of Turku, Finland
| | - Jatta S Takkinen
- PET Preclinical Imaging Laboratory, Turku PET Centre, University of Turku, Finland; MediCity Research Laboratory, University of Turku, Finland
| | - Obada Alzghool
- PET Preclinical Imaging Laboratory, Turku PET Centre, University of Turku, Finland; MediCity Research Laboratory, University of Turku, Finland
| | - Johan Rajander
- Accelerator Laboratory, Turku PET Centre, Åbo Akademi University, Finland
| | - Simo Teperi
- Department of Biostatistics, University of Turku, Finland
| | - Fanny Cacheux
- CEA, I2BM, Service Hospitalier Frédéric Joliot, Orsay, France
| | | | - Frédéric Dollé
- CEA, I2BM, Service Hospitalier Frédéric Joliot, Orsay, France
| | - Juha O Rinne
- Turku PET Centre, Division of Clinical Neurosciences, Turku University Hospital, Turku, Finland
| | - Olof Solin
- Radiopharmaceutical Chemistry Laboratory, Turku PET Centre, University of Turku, Finland; Department of Chemistry, University of Turku, Finland; Accelerator Laboratory, Turku PET Centre, Åbo Akademi University, Finland
| | - Merja Haaparanta-Solin
- PET Preclinical Imaging Laboratory, Turku PET Centre, University of Turku, Finland; MediCity Research Laboratory, University of Turku, Finland
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TSPO in diverse CNS pathologies and psychiatric disease: A critical review and a way forward. Pharmacol Ther 2018; 194:44-58. [PMID: 30189290 DOI: 10.1016/j.pharmthera.2018.09.003] [Citation(s) in RCA: 101] [Impact Index Per Article: 16.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
The use of Translocator Protein 18 kDa (TSPO) as a clinical neuroimaging biomarker of brain injury and neuroinflammation has increased exponentially in the last decade. There has been a furious pace in the development of new radiotracers for TSPO positron emission tomography (PET) imaging and its use has now been extensively described in many neurological and mental disorders. This fast pace of research and the ever-increasing number of new laboratories entering the field often times lack an appreciation of the historical perspective of the field and introduce dogmatic, but unproven facts, related to the underlying neurobiology of the TSPO response to brain injury and neuroinflammation. Paradoxically, while in neurodegenerative disorders and in all types of CNS pathologies brain TSPO levels increase, a new observation in psychiatric disorders such as schizophrenia is decreased brain levels of TSPO measured by PET. The neurobiological bases for this new finding is currently not known, but rigorous experimental design using multiple experimental approaches and careful interpretation of results is critically important to provide the methodological and/or biological underpinnings to this new observation. This review provides a perspective of the early history of validating TSPO as a biomarker of brain injury and neuroinflammation and a critical analysis of controversial topics in the literature related to the cellular sources of the TSPO response. The latter is important in order to provide the correct interpretation of PET studies in neurodegenerative and psychiatric disorders. Furthermore, this review proposes some yet to be explored explanations to new findings in psychiatric disorders and new approaches to quantitatively assess the glial sources of the TSPO response in order to move the field forward.
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Abstract
Lung inflammatory diseases contribute significantly to the socioeconomic burden of disease. Yet very few new, effective therapies for respiratory disease have been approved for use. A major contributing factor is the lack of biomarkers that can accurately quantify the lung inflammatory burden and can be used to understand the contribution of lung inflammation to loss in lung function. Molecular imaging approaches can detect and quantify the recruitment and activation of specific immune cells in lung inflammation. We review the clinical techniques used to image lung inflammation, provide an overview of clinical and emerging PET techniques for quantifying lung inflammation, and discuss potential clinical applications.
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Affiliation(s)
| | - Delphine L Chen
- Washington University School of Medicine, St. Louis, Missouri
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10
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Biesmans S, Acton PD, Cotto C, Langlois X, Ver Donck L, Bouwknecht JA, Aelvoet SA, Hellings N, Meert TF, Nuydens R. Effect of stress and peripheral immune activation on astrocyte activation in transgenic bioluminescent Gfap-luc mice. Glia 2015; 63:1126-37. [PMID: 25690758 DOI: 10.1002/glia.22804] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2013] [Accepted: 01/22/2015] [Indexed: 12/13/2022]
Abstract
Neuroinflammation and the accompanying activation of glial cells is an important feature of many neurodegenerative conditions. It is known that factors such as peripheral infections and stress can influence immune processes in the brain. However, the effect of these stressors on astrocyte activation in vivo remains elusive. In this study, transgenic Gfap-luc mice expressing the luciferase gene under the transcriptional control of the glial fibrillary acidic protein promoter were used to quantify the kinetics of in vivo astrocyte activation following immune challenges relevant to clinical inflammation. It was found that astrocytes respond rapidly to peripheral immune activation elicited by either bacterial lipopolysaccharide (LPS) or the viral mimetic polyinosinic:polycytidylic acid (poly(I:C)). By measuring bioluminescence and 18-kDa translocator protein radioligand binding in the same animal it was observed that LPS induces both astrocyte as well as microglial activation at 6 h post-administration. Furthermore, the astrocyte response decreased upon repeated systemic LPS injections, indicating development of tolerance to the LPS challenge. Finally, restraining Gfap-luc mice for 1 h daily on 5 consecutive days did not affect brain bioluminescence, thereby indicating that sub-chronic stress does not influence astrocyte activation under unchallenged conditions. However, stressed animals showed a reduced response to a subsequent systemic LPS injection, suggesting that the immune system is compromised in these animals. Here, we demonstrate that Gfap-luc mice can be used to study astrocyte activation in response to stimuli relevant for clinical inflammation and that this approach may provide a more complete characterization of existing and novel models of neuroinflammation
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Affiliation(s)
- Steven Biesmans
- Biomedical Research Institute, Hasselt University, Agoralaan C Building, Diepenbeek, Belgium; Neurosciences, Janssen Research & Development, A Division of Janssen Pharmaceutica NV, Beerse, Belgium
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11
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Gammon ST, Foje N, Brewer EM, Owers E, Downs CA, Budde MD, Leevy WM, Helms MN. Preclinical anatomical, molecular, and functional imaging of the lung with multiple modalities. Am J Physiol Lung Cell Mol Physiol 2014; 306:L897-914. [DOI: 10.1152/ajplung.00007.2014] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
In vivo imaging is an important tool for preclinical studies of lung function and disease. The widespread availability of multimodal animal imaging systems and the rapid rate of diagnostic contrast agent development have empowered researchers to noninvasively study lung function and pulmonary disorders. Investigators can identify, track, and quantify biological processes over time. In this review, we highlight the fundamental principles of bioluminescence, fluorescence, planar X-ray, X-ray computed tomography, magnetic resonance imaging, and nuclear imaging modalities (such as positron emission tomography and single photon emission computed tomography) that have been successfully employed for the study of lung function and pulmonary disorders in a preclinical setting. The major principles, benefits, and applications of each imaging modality and technology are reviewed. Limitations and the future prospective of multimodal imaging in pulmonary physiology are also discussed. In vivo imaging bridges molecular biological studies, drug design and discovery, and the imaging field with modern medical practice, and, as such, will continue to be a mainstay in biomedical research.
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Affiliation(s)
- Seth T. Gammon
- Department of Cancer Systems Imaging, The University of Texas MD Anderson Cancer Center, Houston, Texas
| | - Nathan Foje
- Department of Biological Sciences, Notre Dame Integrated Imaging Facility, Notre Dame, Indiana
| | - Elizabeth M. Brewer
- Department of Pediatrics Center for Cystic Fibrosis and Airways Disease Research, Emory University, Atlanta, Georgia
| | - Elizabeth Owers
- Department of Biological Sciences, Notre Dame Integrated Imaging Facility, Notre Dame, Indiana
| | - Charles A. Downs
- Nell Hodgson Woodruff School of Nursing, Emory University, Atlanta, Georgia; and
| | - Matthew D. Budde
- Department of Neurosurgery, Medical College of Wisconsin, Milwaukee, Wisconsin
| | - W. Matthew Leevy
- Department of Biological Sciences, Notre Dame Integrated Imaging Facility, Notre Dame, Indiana
| | - My N. Helms
- Department of Pediatrics Center for Cystic Fibrosis and Airways Disease Research, Emory University, Atlanta, Georgia
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12
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Foss CA, Harper JS, Wang H, Pomper MG, Jain SK. Noninvasive molecular imaging of tuberculosis-associated inflammation with radioiodinated DPA-713. J Infect Dis 2013; 208:2067-74. [PMID: 23901092 DOI: 10.1093/infdis/jit331] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
BACKGROUND Increased expression of translocator protein (TSPO) is a feature of microglial and macrophage activation. Since activated macrophages are key components of tuberculosis-associated inflammation, we evaluated radioiodinated DPA-713, a synthetic ligand of TSPO, for in vivo imaging of host response. METHODS Mice were infected with aerosolized Mycobacterium tuberculosis and evaluated using whole-body [(125)I]iodo-DPA-713 single-photon emission computed tomography (SPECT). Ex vivo biodistribution and correlative immunofluorescence studies were also performed. RESULTS [(125)I]Iodo-DPA-713 SPECT imaging clearly delineated tuberculosis-associated pulmonary inflammation in live animals. Biodistribution studies confirmed radiotracer specificity for inflamed pulmonary tissues. Immunofluorescence studies demonstrated that TSPO is highly expressed in CD68(+) macrophages and phagocytic cells within tuberculosis lesions and that [(125)I]DPA-713 specifically accumulates within these cells. Coadministration of excess unlabelled DPA-713 abrogated both the SPECT and ex vivo fluorescence signals. Lesion-specific signal-to-noise ratios were significantly higher with [(125)I]iodo-DPA-713 SPECT (4.06 ± 0.52) versus [(18)F]fluorodeoxyglucose (FDG) positron emission tomography (PET) (2.00 ± 0.28) performed in the same mice (P = .004). CONCLUSIONS [(125)I]Iodo-DPA-713 accumulates specifically in tuberculosis-associated inflammatory lesions by selective retention within macrophages and phagocytic cells. [(125)I]Iodo-DPA-713 SPECT provides higher lesion-specific signal-to-noise ratios than [(18)F]FDG PET and may prove to be a more specific biomarker to monitor tuberculosis in situ.
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Joo HK, Lee YR, Lim SY, Lee EJ, Choi S, Cho EJ, Park MS, Ryoo S, Park JB, Jeon BH. Peripheral benzodiazepine receptor regulates vascular endothelial activations via suppression of the voltage-dependent anion channel-1. FEBS Lett 2012; 586:1349-55. [PMID: 22616995 DOI: 10.1016/j.febslet.2012.03.049] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2012] [Revised: 03/18/2012] [Accepted: 03/22/2012] [Indexed: 01/22/2023]
Abstract
Peripheral benzodiazepine receptor (PBR) is a multifunctional protein mainly found on the outer mitochondrial membrane. PBR expression is increased by tumor necrosis factor-α (TNF-α) in endothelial cells. Adenoviral overexpression of PBR inhibits monocyte adhesion, VCAM-1, and ICAM-1 expression in TNF-α-activated endothelial cells. Rotenone, cyclosporine A, and bongkrekic acid suppress TNF-α-induced VCAM-1 expression. Overexpression of PBR inhibits voltage-dependent anion channel-1 (VDAC-1) expression and the silencing of PBR increases VDAC-1 expression in endothelial cells. Moreover, TNF-α-induced VCAM-1 expression is suppressed by VDAC-1 gene silencing. PBR overexpression significantly decreases TNF-α-induced mitochondrial reactive oxygen species and MnSOD expression. These results suggest that PBR can inhibit endothelial activation and this action is related to the inhibition of mitochondrial ROS and/or VDAC-1 expression in endothelial cells.
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Affiliation(s)
- Hee Kyoung Joo
- Infectious Signaling Network Research Center and Research Institute for Medical Sciences, Department of Physiology, School of Medicine, Chungnam National University, Daejeon, Republic of Korea
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Kumata K, Yui J, Hatori A, Fujinaga M, Yanamoto K, Yamasaki T, Kawamura K, Wakizaka H, Nengaki N, Yoshida Y, Ogawa M, Fukumura T, Zhang MR. Synthesis and Evaluation of Novel Carbon-11 Labeled Oxopurine Analogues for Positron Emission Tomography Imaging of Translocator Protein (18 kDa) in Peripheral Organs. J Med Chem 2011; 54:6040-9. [DOI: 10.1021/jm200516a] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Katsushi Kumata
- Department of Molecular Probes, Molecular Imaging Center, National Institute of Radiological Sciences, 4-9-1 Anagawa, Inage-ku, Chiba 263-8555, Japan
| | - Joji Yui
- Department of Molecular Probes, Molecular Imaging Center, National Institute of Radiological Sciences, 4-9-1 Anagawa, Inage-ku, Chiba 263-8555, Japan
| | - Akiko Hatori
- Department of Molecular Probes, Molecular Imaging Center, National Institute of Radiological Sciences, 4-9-1 Anagawa, Inage-ku, Chiba 263-8555, Japan
| | - Masayuki Fujinaga
- Department of Molecular Probes, Molecular Imaging Center, National Institute of Radiological Sciences, 4-9-1 Anagawa, Inage-ku, Chiba 263-8555, Japan
| | - Kazuhiko Yanamoto
- Department of Molecular Probes, Molecular Imaging Center, National Institute of Radiological Sciences, 4-9-1 Anagawa, Inage-ku, Chiba 263-8555, Japan
| | - Tomoteru Yamasaki
- Department of Molecular Probes, Molecular Imaging Center, National Institute of Radiological Sciences, 4-9-1 Anagawa, Inage-ku, Chiba 263-8555, Japan
| | - Kazunori Kawamura
- Department of Molecular Probes, Molecular Imaging Center, National Institute of Radiological Sciences, 4-9-1 Anagawa, Inage-ku, Chiba 263-8555, Japan
| | - Hidekatsu Wakizaka
- Department of Molecular Probes, Molecular Imaging Center, National Institute of Radiological Sciences, 4-9-1 Anagawa, Inage-ku, Chiba 263-8555, Japan
| | - Nobuki Nengaki
- Department of Molecular Probes, Molecular Imaging Center, National Institute of Radiological Sciences, 4-9-1 Anagawa, Inage-ku, Chiba 263-8555, Japan
- SHI Accelerator Service Co. Ltd., 5-9-11 Kitashinagawa, Shinagawa-ku, Tokyo 141-8686, Japan
| | - Yuichiro Yoshida
- Department of Molecular Probes, Molecular Imaging Center, National Institute of Radiological Sciences, 4-9-1 Anagawa, Inage-ku, Chiba 263-8555, Japan
- SHI Accelerator Service Co. Ltd., 5-9-11 Kitashinagawa, Shinagawa-ku, Tokyo 141-8686, Japan
| | - Masanao Ogawa
- Department of Molecular Probes, Molecular Imaging Center, National Institute of Radiological Sciences, 4-9-1 Anagawa, Inage-ku, Chiba 263-8555, Japan
- SHI Accelerator Service Co. Ltd., 5-9-11 Kitashinagawa, Shinagawa-ku, Tokyo 141-8686, Japan
| | - Toshimitsu Fukumura
- Department of Molecular Probes, Molecular Imaging Center, National Institute of Radiological Sciences, 4-9-1 Anagawa, Inage-ku, Chiba 263-8555, Japan
| | - Ming-Rong Zhang
- Department of Molecular Probes, Molecular Imaging Center, National Institute of Radiological Sciences, 4-9-1 Anagawa, Inage-ku, Chiba 263-8555, Japan
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Zheng J, Boisgard R, Siquier-Pernet K, Decaudin D, Dollé F, Tavitian B. Differential Expression of the 18 kDa Translocator Protein (TSPO) by Neoplastic and Inflammatory Cells in Mouse Tumors of Breast Cancer. Mol Pharm 2011; 8:823-32. [DOI: 10.1021/mp100433c] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Affiliation(s)
- Jinzi Zheng
- Laboratoire d'Imagerie Moléculaire Expérimentale, Université Paris Sud, INSERM Unit 1023, 4 Place du Général Leclerc, F-91400 Orsay, France
| | - Raphaël Boisgard
- Laboratoire d'Imagerie Moléculaire Expérimentale, Université Paris Sud, INSERM Unit 1023, 4 Place du Général Leclerc, F-91400 Orsay, France
| | - Karine Siquier-Pernet
- Laboratoire d'Imagerie Moléculaire Expérimentale, Université Paris Sud, INSERM Unit 1023, 4 Place du Général Leclerc, F-91400 Orsay, France
| | - Didier Decaudin
- Laboratory of Preclinical Investigation, Institut Curie, 26 rue d'Ulm, F-75248 Paris, France
| | - Frédéric Dollé
- Institut d'Imagerie BioMédicale, Service Hospitalier Frédéric Joliot, Commissariat a l'Énergie Atomique, 4 Place du Général Leclerc, F-91400, France
| | - Bertrand Tavitian
- Laboratoire d'Imagerie Moléculaire Expérimentale, Université Paris Sud, INSERM Unit 1023, 4 Place du Général Leclerc, F-91400 Orsay, France
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In vivo imaging and quantitative analysis of TSPO in rat peripheral tissues using small-animal PET with [18F]FEDAC. Nucl Med Biol 2010; 37:853-60. [DOI: 10.1016/j.nucmedbio.2010.04.183] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2010] [Revised: 04/19/2010] [Accepted: 04/19/2010] [Indexed: 11/23/2022]
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Ito F, Toyama H, Kudo G, Suzuki H, Hatano K, Ichise M, Katada K, Ito K, Sawada M. Two activated stages of microglia and PET imaging of peripheral benzodiazepine receptors with [11C]PK11195 in rats. Ann Nucl Med 2010; 24:163-9. [DOI: 10.1007/s12149-009-0339-0] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2009] [Accepted: 12/08/2009] [Indexed: 11/28/2022]
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18
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Kiesewetter DO, Lang L, Ma Y, Bhattacharjee AK, Gao ZG, Joshi BV, Melman A, de Castro S, Jacobson KA. Synthesis and characterization of [76Br]-labeled high-affinity A3 adenosine receptor ligands for positron emission tomography. Nucl Med Biol 2009; 36:3-10. [PMID: 19181263 DOI: 10.1016/j.nucmedbio.2008.10.003] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2008] [Revised: 10/02/2008] [Accepted: 10/13/2008] [Indexed: 11/19/2022]
Abstract
INTRODUCTION Bromine-76-radiolabeled analogues of previously reported high-affinity A(3) adenosine receptor (A(3)AR) nucleoside ligands have been prepared as potential radiotracers for positron emission tomography. METHODS The radiosyntheses were accomplished by oxidative radiobromination on the N(6)-benzyl moiety of trimethyltin precursors. Biodistribution studies of the kinetics of uptake were conducted in awake rats. RESULTS We prepared an agonist ligand {[(76)Br](1'S,2'R,3'S,4'R,5'S)-4'-{2-chloro-6-[(3-bromophenylmethyl)amino]purin-9-yl}-1'-(methylaminocarbonyl)bicyclo[3.1.0]hexane-2',3'-diol (MRS3581)} in 59% radiochemical yield with a specific activity of 19.5 GBq/micromol and an antagonist ligand {[(76)Br](1'R,2'R,3'S,4'R,5'S)-4'-(6-(3-bromobenzylamino)-2-chloro-9H-purin-9-yl)bicyclo[3.1.0]hexane-2',3'-diol (MRS5147)} in 65% radiochemical yield with a specific activity of 22 GBq/micromol. The resultant products exhibited the expected high affinity (K(i) approximately 0.6 nM) and specific binding at the human A(3)AR in vitro. Biodistribution studies in the rat showed uptake in the organs of excretion and metabolism. The antagonist MRS5147 exhibited increasing uptake in testes, an organ that contains significant quantities of A(3)AR, over a 2-h time course, which suggests the presence of a specific A(3)AR retention mechanism. CONCLUSION We were able to compare uptake of the [(76)Br]-labeled antagonist MRS5147 to [(76)Br]agonist MRS3581. The antagonist MRS5147 shows increasing uptake in the testes, an A(3)AR-rich tissue, suggesting that this ligand may have promise as a molecular imaging agent.
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Affiliation(s)
- Dale O Kiesewetter
- Positron Emission Tomography Radiochemistry Group, NIBIB, Clinical Center, National Institutes of Health, Bethesda, MD 20892, USA.
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Kropholler MA, Boellaard R, Elzinga EH, van der Laken CJ, Maruyama K, Kloet RW, Voskuyl AE, Dijkmans BAC, Lammertsma AA. Quantification of (R)-[11C]PK11195 binding in rheumatoid arthritis. Eur J Nucl Med Mol Imaging 2008; 36:624-31. [DOI: 10.1007/s00259-008-0987-7] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2008] [Accepted: 10/09/2008] [Indexed: 10/21/2022]
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20
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PET scanning of macrophages in patients with scleroderma fibrosing alveolitis. Nucl Med Biol 2008; 35:901-9. [DOI: 10.1016/j.nucmedbio.2008.10.001] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2008] [Revised: 08/11/2008] [Accepted: 10/01/2008] [Indexed: 11/17/2022]
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21
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Uptake of inflammatory cell marker [11C]PK11195 into mouse atherosclerotic plaques. Eur J Nucl Med Mol Imaging 2008; 36:73-80. [DOI: 10.1007/s00259-008-0919-6] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2008] [Accepted: 08/01/2008] [Indexed: 10/21/2022]
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22
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Cappelli A, Mancini A, Sudati F, Valenti S, Anzini M, Belloli S, Moresco RM, Matarrese M, Vaghi M, Fabro A, Fazio F, Vomero S. Synthesis and biological characterization of novel 2-quinolinecarboxamide ligands of the peripheral benzodiazepine receptors bearing technetium-99m or rhenium. Bioconjug Chem 2008; 19:1143-53. [PMID: 18510350 DOI: 10.1021/bc700437g] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Potential receptor imaging agents based on Tc-99m for the in vivo visualization of the peripheral benzodiazepine receptor (PBR) have been designed on the basis of the information provided by the previously published structure-affinity relationship studies, which suggested the existence of tolerance to voluminous substituents in the receptor area interacting with 3-position of the quinoline nucleus of 2-quinolinecarboxamides 5. In the first step of the investigation, the stereoelectronic features of the above-indicated receptor area were also probed by means of 4-phenyl-3-[(1-piperazinyl)methyl]-2-quinolinecarboxamide derivatives bearing different substituents on the terminal piperazine nitrogen atom (compounds 6a-f). The structure-affinity relationship data confirmed the existence of a tolerance to bulky lipophilic substituents and stimulated the design of bifunctional ligands based on the 4-phenyl-3-[(1-piperazinyl)methyl]-2-quinolinecarboxamide moiety (compounds 6h,j,k,m). The submicromolar PBR affinity of rhenium complexes 6j,m suggests that the presence of their metal-ligand moieties with encaged rhenium is fairly compatible with the interaction with the PBR binding site. Thus, in order to obtain information on the in vivo behavior of these bifunctional ligands, (99m)Tc-labeled compounds 6h,k were synthesized and evaluated in preliminary biodistribution and single photon emission tomography (SPET) studies. The results suggest that both tracers do not present a clear preferential distribution in tissues rich in PBR, probably because of their molecular dimensions, which may hamper both the intracellular diffusion toward PBR and the interaction with the binding site.
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Affiliation(s)
- Andrea Cappelli
- Dipartimento Farmaco Chimico Tecnologico and European Research Centre for Drug Discovery and Development, Università degli Studi di Siena, Via A. Moro, 53100 Siena, Italy.
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Deane NG, Manning HC, Foutch AC, Washington MK, Aronow BJ, Aronow BA, Bornhop DJ, Coffey RJ. Targeted imaging of colonic tumors in smad3-/- mice discriminates cancer and inflammation. Mol Cancer Res 2007; 5:341-9. [PMID: 17426249 DOI: 10.1158/1541-7786.mcr-06-0225] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
The peripheral benzodiazepine receptor (PBR) is a trans-mitochondrial membrane protein that modulates steroid biosynthesis. Recently, up-regulation and nuclear localization of PBR has been shown to be associated with colon, prostate, and breast cancer. PBR has been targeted by the exogenous synthetic ligand, PK11195, for various purposes including imaging. To capitalize on these observations, we developed a high-throughput, noninvasive, in vivo imaging approach to detect spontaneously arising colonic tumors in mice using a novel PBR-targeted molecular imaging agent (NIR-conPK11195). NIR-conPK11195 localized and was retained in colonic adenomas and carcinomas in Smad3(-/-) mice but not in non-neoplastic hamartomas or chronically inflamed colonic tissue. Using a fluorescence signal-to-noise ratio of > or =4-fold 13 h after injection of the agent, we detected colonic tumors with a sensitivity of 67% and a specificity of 86% in a cohort of 37 Smad3(-/-) mice and control littermates. Furthermore, using oral administration of dextran sulfate to induce colonic inflammation, we showed that the clearance profile of NIR-conPK11195 distinguished transient uptake in inflammatory tissue from longer term retention in tumors. Taken together, these results indicate that NIR-conPK11195 is a promising optical molecular imaging tool to rapidly screen for colonic tumors in mice and to discriminate inflammation from cancer.
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Affiliation(s)
- Natasha G Deane
- Department of Surgery and Division of Surgical Oncology, Vanderbilt University, Nashville, TN 37235, USA
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Solon EG. Autoradiography: high-resolution molecular imaging in pharmaceutical discovery and development. Expert Opin Drug Discov 2007; 2:503-14. [DOI: 10.1517/17460441.2.4.503] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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25
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Chen DL, Schuster DP. Imaging pulmonary inflammation with positron emission tomography: a biomarker for drug development. Mol Pharm 2007; 3:488-95. [PMID: 17009847 DOI: 10.1021/mp060050w] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Methods currently used to assess lung and airway inflammation are often poorly quantitative, invasive, nonspecific, or insensitive. Positron emission tomography (PET) with [18F]fluorodeoxyglucose [18F]FDG), on the other hand, is a noninvasive, highly sensitive imaging technique that can be used to quantify pulmonary inflammation. [18F]FDG, an analogue of glucose, is taken up by the same transporters that take up glucose into the cell; therefore, [18F]FDG uptake tracks cellular glucose transport, which is highly correlated to the rate of cellular glucose metabolism. Recent studies in animal models of neutrophilic lung inflammation, as well as in patients with inflammatory lung disease, indicate that increased [18F]FDG uptake by the lungs correlates with the number of activated neutrophils recovered from the lungs. Therefore, the in vivo measurement of pulmonary glucose metabolism is a measure of neutrophil burden within the lungs. We propose that FDG-PET imaging can be used as a measurable biomarker in the development of drug therapies targeting lung inflammation.
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Affiliation(s)
- Delphine L Chen
- Mallinckrodt Institute of Radiology and Department of Internal Medicine, Washington University School of Medicine, St Louis, Missouri 63110, USA.
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