scholarly journals In Vivo Imaging of Local Inflammation: Monitoring LPS-Induced CD80/CD86 Upregulation by PET

2020 ◽  
Author(s):  
Marco F. Taddio ◽  
Claudia A. Castro Jaramillo ◽  
Peter Runge ◽  
Alain Blanc ◽  
Claudia Keller ◽  
...  
Keyword(s):  
Immune Cells ◽  
Immune Cell ◽  
Ex Vivo ◽  
Tracer Uptake ◽  
Local Inflammation ◽  
Inoculation Site ◽  
Positron Emission ◽  
Pet Ct ◽  
Antigen Presenting

Abstract Purpose The co-stimulatory molecules CD80 and CD86 are upregulated on activated antigen-presenting cells (APC). We investigated whether local APC activation, induced by subcutaneous (s.c.) inoculation of lipopolysaccharides (LPS), can be imaged by positron emission tomography (PET) with CD80/CD86-targeting 64Cu-labelled abatacept. Procedures Mice were inoculated s.c. with extracellular-matrix gel containing either LPS or vehicle (PBS). Immune cell populations were analysed by flow cytometry and marker expression by RT-qPCR. 64Cu-NODAGA-abatacept distribution was analysed using PET/CT and ex vivo biodistribution. Results The number of CD80+ and CD86+ immune cells at the LPS inoculation site significantly increased a few days after inoculation. CD68 and CD86 expression were higher at the LPS than the PBS inoculation site, and CD80 was only increased at the LPS inoculation site. CTLA-4 was highest 10 days after LPS inoculation, when CD80/CD86 decreased again. A few days after inoculation, 64Cu-NODAGA-abatacept distribution to the inoculation site was significantly higher for LPS than PBS (4.2-fold). Co-administration of unlabelled abatacept or human immunoglobulin reduced tracer uptake. The latter reduced the number of CD86+ immune cells at the LPS inoculation site. Conclusions CD80 and CD86 are upregulated in an LPS-induced local inflammation, indicating invasion of activated APCs. 64Cu-NODAGA-abatacept PET allowed following APC activation over time.

Abstract 530: In vivo DVT Inflammation Presages Vein Wall Injury, and is Ameliorated by Statin Therapy

2017 ◽  
Vol 37 (suppl_1) ◽  
Author(s):  
Chase W Kessinger ◽  
Guanming Qi ◽  
Ahmed Tawakol ◽  
Peter K Henke ◽  
Farouc A Jaffer
Keyword(s):  
Statin Therapy ◽  
Fdg Pet ◽  
Ex Vivo ◽  
Vena Cava ◽  
Standard Uptake Value ◽  
Vein Wall ◽  
Positron Emission ◽  
Pet Ct ◽  
Fdg Pet Ct

Objective: Inflammation mediates early venous thrombosis (VT) resolution and can induce vein wall scarring (VWS), a key driver of the morbid post-thrombotic syndrome (PTS). Statins exhibit anti-inflammatory properties, and may positively impact VWS after VT. However, whether early inflammation contributes to this process and can be detected is not known. In this study, we hypothesized that early VT inflammation detected by 18F-fludeoxyglucose (FDG) positron emission tomography/computed tomography (PET/CT) could predict subsequent VWS and that both VT inflammation and VWS would be attenuated by statin therapy. Methods: Stasis VT was induced by complete ligation in male C57BL/6J mice (n=55) in either the infrarenal inferior vena cava (IVC, n=42) or right jugular vein (n=13). IVC VT mice were randomized to statin or control groups. Statin (rosuvastatin 5mg/kg) was given by oral gavage starting one day prior to VT induction; control mice received PBS. All mice underwent survival FDG-PET/CT venography imaging on day 2. FDG-PET inflammation signals (standard uptake value (SUV), SUVmax, target-to-background ratios (TBR)) were measured. Picrosirius red staining of day 14 VT sections measured vein wall collagen/thickness. Ex vivo VT tissue gamma counting of a subgroup was performed at day 2. Whole-thrombus protein/mRNA and VT tissue sections assessed neutrophil content. Results: FDG-PET/CT at day 2 revealed increased FDG uptake in jugular VT over the contralateral sham surgery vein (p<0.001). Statin-treated mice showed a decrease in FDG-PET SUV, SUVmax and TBR (p<0.05 for all). Whole-thrombus analyses and tissue section immunostaining showed reduced thrombus neutrophil content at day 2, without reducing GLUT1 or MPO expression (p>0.05). At day 14, statin therapy significantly reduced VWS (p=0.02). In mice undergoing survival imaging, the day 2 FDG-PET VT inflammation signal correlated significantly with the magnitude of day 14 VWS (IVC VT r=0.74, p<0.001) and jugular models of VT (r=0.62, p=0.02). Conclusions: Quantitative FDG inflammation imaging demonstrates that early VT inflammation presages subsequent VWS, and is ameliorated by prophylactic statin therapy. The overall findings support the concept that statins and could reduce VWS and PTS.

scholarly journals Synthesis and Biological Evaluation of a Radiolabeled PET Probe for Visualization of In Vivo α-Fucosidase Expression

2021 ◽  
Vol 14 (8) ◽  
pp. 745
Author(s):  
Jonathan Cotton ◽  
Chris Marc Goehring ◽  
Anna Kuehn ◽  
Andreas Maurer ◽  
Kerstin Fuchs ◽  
...  
Keyword(s):  
Ex Vivo ◽  
Sodium Hydride ◽  
Biological Evaluation ◽  
Tracer Uptake ◽  
Mouse Serum ◽  
Molar Activity ◽  
Pet Tracer ◽  
Positron Emission

The acidic hydrolase α-fucosidase (AF) is a biomarker for maladies such as cancer and inflammation. The most advanced probes for α-fucosidase are unfortunately constrained to ex vivo or in vitro applications. The in vivo detection and quantification of AF using positron emission tomography would allow for better discovery and diagnosis of disease as well as provide better understanding of disease progression. We synthesized, characterized, and evaluated a radiolabeled small molecule inhibitor of AF based on a known molecule. The radiosynthesis involved the 11C methylation of a phenoxide, which was generated in situ by ultrasonification of the precursor with sodium hydride. The tracer was produced with a decay corrected yield of 41.7 ± 16.5% and had a molar activity of 65.4 ± 30.3 GBq/μmol. The tracer was shown to be stable in mouse serum at 60 min. To test the new tracer, HCT116 colorectal carcinoma cells were engineered to overexpress human AF. In vitro evaluation revealed 3.5-fold higher uptake in HCT116AF cells compared to HCT116 controls (26.4 ± 7.8 vs. 7.5 ± 1.0 kBq/106 cells). Static PET scans 50 min post injection revealed 2.5-fold higher tracer uptake in the HCT116AF tumors (3.0 ± 0.8%ID/cc (n = 6)) compared with the controls (1.2 ± 0.8 (n = 5)). Dynamic scans showed higher uptake in the HCT116AF tumors at all time-points (n = 2). Ex vivo analysis of the tumors, utilizing fluorescent DDK2 antibodies, confirmed the expression of human AF in the HCT116AF xenografts. We have developed a novel PET tracer to image AF in vivo and will now apply this to relevant disease models.

Comparison of 68Ga- and fluorescence-labeled microspheres for measurement of relative pulmonary perfusion in anesthetized pigs

2018 ◽  
Vol 57 (03) ◽  
pp. 100-107
Author(s):  
Martin Scharffenberg ◽  
Anne Naumann ◽  
Thomas Bluth ◽  
Marcelo de Abreu ◽  
Jörg Kotzerke ◽  
...  
Keyword(s):  
Prone Position ◽  
Ex Vivo ◽  
Pulmonary Perfusion ◽  
Mechanically Ventilated ◽  
Ex Vivo Perfusion ◽  
Positron Emission ◽  
Pet Ct ◽  
Ct Data ◽  
Perfusion Measurements

Summary Aim: We compared 68Gallium (68Ga)- and fluorescence-labeled microspheres for measurement of pulmonary perfusion distribution in anesthetized pigs without lung injury. Methods: In two mechanically ventilated pigs, the distribution of pulmonary perfusion was marked in vivo with 68Ga- and fluorescence-labeled microspheres in supine and prone position. After each injection, the distribution of 68Ga-labeled microspheres was measured in vivo with positron emission tomography/ computed tomography (PET/CT) in the position in which microspheres were injected and vice versa. The distribution of fluorescence-labeled microspheres was measured ex vivo. Perfusion distributions were compared between methods and postures within four lung regions and along the ventro-dorsal gradient. After each injection of 68Ga-labeled microspheres, changes in ventro-dorsal perfusion gradients induced by repositioning were compared for volume- and mass-normalized PET/CT measurements. Results: Regional and gradient analyses of in vivo and ex vivo measurements, respectively, consistently revealed higher pulmonary perfusion in dorsal than ventral regions in supine positioned animals. Both methods showed more pronounced perfusion gradients in supine compared to prone position. Changes in animal position were associated with alterations in the ventro-dorsal perfusion gradient when volume-, but not mass-normalization was conducted for PET/CT data. Conclusions: Ex vivo fluorescence- and in vivo 68Ga-labeled microspheres measurements revealed similar perfusion distributions. Mass-normalized perfusion measurements by 68Ga-labeled microspheres and PET/CT were not affected by positioning artifacts.

Molecular Imaging Targeting Corticotropin Releasing Hormone Receptor for Corticotropinoma: A Changing Paradigm

2020 ◽  
Author(s):  
Rama Walia ◽  
Rahul Gupta ◽  
Anil Bhansali ◽  
Rosario Pivonello ◽  
Rajender Kumar ◽  
...  
Keyword(s):  
Molecular Imaging ◽  
Cushing’S Syndrome ◽  
Cushing's Syndrome ◽  
Tracer Uptake ◽  
Releasing Hormone ◽  
Positron Emission ◽  
Pet Ct ◽  
Gallium 68 ◽  
Operative Findings

Abstract Background Corticotrophin releasing hormone (CRH) is the major regulator of ACTH secretion from the anterior pituitary and acts via CRH-1 receptors (CRH-1R). Corticotropinoma though autonomous still retain their responsiveness to CRH and hence, we hypothesize that in vivo detection of CRH-1 receptors on pituitary adenoma using Gallium-68 ( 68Ga) tagged CRH can indicate the functionality of adenoma and combining it with Positron emission tomography-computed tomography (PET-CT) can provide requisite anatomical information. Methods Subjects with ACTH dependent Cushing's syndrome (CS) [n = 27, 24: Cushing's disease (CD), 3: ectopic Cushing's syndrome (ECS)] underwent 68Ga CRH PET-CT. Two nuclear medicine physicians read these images for adenoma delineation and superimposed them on MRI sella. The information so provided was used for intra-operative navigation and compared with operative and histopathological findings. Findings 68Ga CRH PET-CT correctly delineated corticotropinoma in all the 24 cases of CD, including the ten cases with size &lt; 6mm (four cases negative on MRI). Corticotropinoma location on 68Ga CRH PET fusion images with MRI were concordant with operative findings and further confirmed on histopathology. There was no tracer uptake in pituitary in two patients with ECS while in another, the diffuse uptake in pituitary suggested ectopic CRH production. Conclusion 68Ga CRH PET-CT represents a novel non-invasive molecular imaging targeting CRH receptors that not only delineates corticotropinoma and provides surgeon with valuable information for intra-operative tumour navigation but also helps in differentiating pituitary from extra-pituitary source of ACTH dependent Cushing’s syndrome.

scholarly journals Tracking distinct microglia subpopulations with photoconvertible Dendra2 in vivo

2021 ◽  
Vol 18 (1) ◽  
Author(s):  
Eric B. Miller ◽  
Sarah J. Karlen ◽  
Kaitryn E. Ronning ◽  
Marie E. Burns
Keyword(s):  
Immune Cells ◽  
Large Scale ◽  
Fluorescent Protein ◽  
Immune Cell ◽  
Neuronal Damage ◽  
Ex Vivo ◽  
Fluorescent Markers ◽  
Immune Cell Subpopulations ◽  
Cell Subpopulations

Abstract Background The ability to track individual immune cells within the central nervous system has revolutionized our understanding of the roles that microglia and monocytes play in synaptic maintenance, plasticity, and neurodegenerative diseases. However, distinguishing between similar subpopulations of mobile immune cells over time during episodes of neuronal death and tissue remodeling has proven to be challenging. Methods We recombineered a photoconvertible fluorescent protein (Dendra2; D2) downstream of the Cx3cr1 promoter commonly used to drive expression of fluorescent markers in microglia and monocytes. Like the popular Cx3cr1–GFP line (Cx3cr1+/GFP), naïve microglia in Cx3cr1–Dendra2 mice (Cx3cr1+/D2) fluoresce green and can be noninvasively imaged in vivo throughout the CNS. In addition, individual D2-expressing cells can be photoconverted, resulting in red fluorescence, and tracked unambiguously within a field of green non-photoconverted cells for several days in vivo. Results Dendra2-expressing retinal microglia were noninvasively photoconverted in both ex vivo and in vivo conditions. Local in vivo D2 photoconversion was sufficiently robust to quantify cell subpopulations by flow cytometry, and the protein was stable enough to survive tissue processing for immunohistochemistry. Simultaneous in vivo fluorescence imaging of Dendra2 and light scattering measurements (Optical Coherence Tomography, OCT) were used to assess responses of individual microglial cells to localized neuronal damage and to identify the infiltration of monocytes from the vasculature in response to large scale neurodegeneration. Conclusions The ability to noninvasively and unambiguously track D2-expressing microglia and monocytes in vivo through space and time makes the Cx3cr1–Dendra2 mouse model a powerful new tool for disentangling the roles of distinct immune cell subpopulations in neuroinflammation.

scholarly journals Reprogramming Immune Cells for Enhanced Cancer Immunotherapy: Targets and Strategies

2021 ◽  
Vol 12 ◽  
Author(s):  
Yan Dong ◽  
Zhuo Wan ◽  
Xiaotong Gao ◽  
Guodong Yang ◽  
Li Liu
Keyword(s):  
Immune Cells ◽  
Causes Of Death ◽  
Immune Cell ◽  
Ex Vivo ◽  
Immune Surveillance ◽  
Public Health Problem ◽  
Major Public Health Problem ◽  
The Past ◽  
Cancer Types

Cancer is one of the leading causes of death and a major public health problem all over the world. Immunotherapy is becoming a revolutionary clinical management for various cancer types. Restoration of aberrant immune surveillance on cancers has achieved markable progress in the past years by either in vivo or ex vivo engineering of the immune cells. Here, we summarized the central roles of immune cells in tumor progression and regression, and the existing and emerging strategies for different immune cell-based immunotherapies. In addition, the current challenges and the potential solutions in translating the immunotherapies into the clinic are also discussed.

scholarly journals Evaluation of [68Ga]Ga-DOTA-TCTP-1 for the Detection of Metalloproteinase 2/9 Expression in Mouse Atherosclerotic Plaques

Molecules ◽  
2018 ◽  
Vol 23 (12) ◽  
pp. 3168 ◽  
Author(s):  
Max Kiugel ◽  
Sanna Hellberg ◽  
Meeri Käkelä ◽  
Heidi Liljenbäck ◽  
Tiina Saanijoki ◽  
...  
Keyword(s):  
Ex Vivo ◽  
Low Density Lipoprotein ◽  
Density Lipoprotein ◽  
Tracer Uptake ◽  
Atherosclerotic Plaques ◽  
Positron Emission ◽  
Pre Treatment ◽  
Targeting Peptide ◽  
Gallium 68

Background: The expression of matrix metalloproteinases 2/9 (MMP-2/9) has been implicated in arterial remodeling and inflammation in atherosclerosis. We evaluated a gallium-68 labeled peptide for the detection of MMP-2/9 in atherosclerotic mouse aorta. Methods: We studied sixteen low-density lipoprotein receptor deficient mice (LDLR-/-ApoB100/100) kept on a Western-type diet. Distribution of intravenously-injected MMP-2/9-targeting peptide, [68Ga]Ga-DOTA-TCTP-1, was studied by combined positron emission tomography (PET) and contrast-enhanced computed tomography (CT). At 60 min post-injection, aortas were cut into cryosections for autoradiography analysis of tracer uptake, histology, and immunohistochemistry. Zymography was used to assess MMP-2/9 activation and pre-treatment with MMP-2/9 inhibitor to assess the specificity of tracer uptake. Results: Tracer uptake was not visible by in vivo PET/CT in the atherosclerotic aorta, but ex vivo autoradiography revealed 1.8 ± 0.34 times higher tracer uptake in atherosclerotic plaques than in normal vessel wall (p = 0.0029). Tracer uptake in plaques correlated strongly with the quantity of Mac-3-positive macrophages (R = 0.91, p < 0.001), but weakly with MMP-9 staining (R = 0.40, p = 0.099). Zymography showed MMP-2 activation in the aorta, and pre-treatment with MMP-2/9 inhibitor decreased tracer uptake by 55% (p = 0.0020). Conclusions: The MMP-2/9-targeting [68Ga]Ga-DOTA-TCTP-1 shows specific uptake in inflamed atherosclerotic lesions; however, a low target-to-background ratio precluded in vivo vascular imaging. Our results suggest, that the affinity of gelatinase imaging probes should be steered towards activated MMP-2, to reduce the interference of circulating enzymes on the target visualization in vivo.

scholarly journals 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

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Marion Chomet ◽  
Maxime Schreurs ◽  
Ricardo Vos ◽  
Mariska Verlaan ◽  
Esther J. Kooijman ◽  
...  
Keyword(s):  
Pet Imaging ◽  
Ex Vivo ◽  
Tracer Uptake ◽  
Tumor Uptake ◽  
Preclinical Models ◽  
Recovery Coefficient ◽  
Tumor Bearing ◽  
Pet Ct ◽  
Ex Vivo Biodistribution

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.

scholarly journals Aerosolized In Vivo 3D Localization of Nose-to-Brain Nanocarrier Delivery Using Multimodality Neuroimaging in a Rat Model—Protocol Development

Pharmaceutics ◽  
2021 ◽  
Vol 13 (3) ◽  
pp. 391
Author(s):  
Michael C. Veronesi ◽  
Brian D. Graner ◽  
Shih-Hsun Cheng ◽  
Marta Zamora ◽  
Hamideh Zarrinmayeh ◽  
...  
Keyword(s):  
Rat Model ◽  
Ex Vivo ◽  
Region Of Interest ◽  
Ct Imaging ◽  
Pet Tracer ◽  
Positron Emission ◽  
Pet Ct ◽  
Activity Measurements ◽  
The Brain

The fate of intranasal aerosolized radiolabeled polymeric micellar nanoparticles (LPNPs) was tracked with positron emission tomography/computer tomography (PET/CT) imaging in a rat model to measure nose-to-brain delivery. A quantitative temporal and spatial testing protocol for new radio-nanotheranostic agents was sought in vivo. LPNPs labeled with a zirconium 89 (89Zr) PET tracer were administered via intranasal or intravenous delivery, followed by serial PET/CT imaging. After 2 h of continuous imaging, the animals were sacrificed, and the brain substructures (olfactory bulb, forebrain, and brainstem) were isolated. The activity in each brain region was measured for comparison with the corresponding PET/CT region of interest via activity measurements. Serial imaging of the LPNPs (100 nm PLA–PEG–DSPE+89Zr) delivered intranasally via nasal tubing demonstrated increased activity in the brain after 1 and 2 h following intranasal drug delivery (INDD) compared to intravenous administration, which correlated with ex vivo gamma counting and autoradiography. Although assessment of delivery from nose to brain is a promising approach, the technology has several limitations that require further development. An experimental protocol for aerosolized intranasal delivery is presented herein, which may provide a platform for better targeting the olfactory epithelium.

scholarly journals A human antibody selective for transthyretin amyloid removes cardiac amyloid through phagocytic immune cells

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Aubin Michalon ◽  
Andreas Hagenbuch ◽  
Christian Huy ◽  
Evita Varela ◽  
Benoit Combaluzier ◽  
...  
Keyword(s):  
Immune Cells ◽  
Ex Vivo ◽  
Phase 1 ◽  
Hereditary Disease ◽  
Elderly Subjects ◽  
Human Antibody ◽  
Cardiac Amyloid ◽  
Healthy Elderly ◽  
Ongoing Phase

AbstractTransthyretin amyloid (ATTR) cardiomyopathy is a debilitating disease leading to heart failure and death. It is characterized by the deposition of extracellular ATTR fibrils in the myocardium. Reducing myocardial ATTR load is a therapeutic goal anticipated to translate into restored cardiac function and improved patient survival. For this purpose, we developed the selective anti-ATTR antibody NI301A, a recombinant human monoclonal immunoglobulin G1. NI301A was cloned following comprehensive analyses of memory B cell repertoires derived from healthy elderly subjects. NI301A binds selectively with high affinity to the disease-associated ATTR aggregates of either wild-type or variant ATTR related to sporadic or hereditary disease, respectively. It does not bind physiological transthyretin. NI301A removes ATTR deposits ex vivo from patient-derived myocardium by macrophages, as well as in vivo from mice grafted with patient-derived ATTR fibrils in a dose- and time-dependent fashion. The biological activity of ATTR removal involves antibody-mediated activation of phagocytic immune cells including macrophages. These data support the evaluation of safety and tolerability of NI301A in an ongoing phase 1 clinical trial in patients with ATTR cardiomyopathy.

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