scholarly journals A Semi Rigid Novel Hydroxamate AMPED-Based Ligand for 89Zr PET Imaging

Molecules ◽  
2021 ◽  
Vol 26 (19) ◽  
pp. 5819
Author(s):  
Lisa Russelli ◽  
Francesco De Rose ◽  
Loredana Leone ◽  
Sybille Reder ◽  
Markus Schwaiger ◽  
...  
Keyword(s):  
Pet Imaging ◽  
Ex Vivo ◽  
Small Animal ◽  
Biologically Active ◽  
Small Animal Pet ◽  
Organ Distribution ◽  
Complexing Agent ◽  
Distribution Studies

In this work, we designed, developed, characterized, and investigated a new chelator and its bifunctional derivative for 89Zr labeling and PET-imaging. In a preliminary study, we synthesized two hexadentate chelators named AAZTHAS and AAZTHAG, based on the seven-membered heterocycle AMPED (6-amino-6-methylperhydro-1,4-diazepine) with the aim to increase the rigidity of the 89Zr complex by using N-methyl-N-(hydroxy)succinamide or N-methyl-N-(hydroxy)glutaramide pendant arms attached to the cyclic structure. N-methylhydroxamate groups are the donor groups chosen to efficiently coordinate 89Zr. After in vitro stability tests, we selected the chelator with longer arms, AAZTHAG, as the best complexing agent for 89Zr presenting a stability of 86.4 ± 5.5% in human serum (HS) for at least 72 h. Small animal PET/CT static scans acquired at different time points (up to 24 h) and ex vivo organ distribution studies were then carried out in healthy nude mice (n = 3) to investigate the stability and biodistribution in vivo of this new 89Zr-based complex. High stability in vivo, with low accumulation of free 89Zr in bones and kidneys, was measured. Furthermore, an activated ester functionalized version of AAZTHAG was synthesized to allow the conjugation with biomolecules such as antibodies. The bifunctional chelator was then conjugated to the human anti-HER2 monoclonal antibody Trastuzumab (Tz) as a proof of principle test of conjugation to biologically active molecules. The final 89Zr labeled compound was characterized via radio-HPLC and SDS-PAGE followed by autoradiography, and its stability in different solutions was assessed for at least 4 days.

scholarly journals Iodine-124 PET quantification of organ-specific delivery and expression of NIS-encoding RNA

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Matthias Miederer ◽  
Stefanie Pektor ◽  
Isabelle Miederer ◽  
Nicole Bausbacher ◽  
Isabell Sofia Keil ◽  
...  
Keyword(s):  
Cell Lines ◽  
Ex Vivo ◽  
Small Animal ◽  
Protein Translation ◽  
The Body ◽  
Small Animal Pet ◽  
Animal Pet ◽  
Organ Specific

Abstract Background RNA-based vaccination strategies tailoring immune response to specific reactions have become an important pillar for a broad range of applications. Recently, the use of lipid-based nanoparticles opened the possibility to deliver RNA to specific sites within the body, overcoming the limitation of rapid degradation in the bloodstream. Here, we have investigated whether small animal PET/MRI can be employed to image the biodistribution of RNA-encoded protein. For this purpose, a reporter RNA coding for the sodium-iodide-symporter (NIS) was in vitro transcribed in cell lines and evaluated for expression. RNA-lipoplex nanoparticles were then assembled by complexing RNA with liposomes at different charge ratios, and functional NIS protein translation was imaged and quantified in vivo and ex vivo by Iodine-124 PET upon intravenous administration in mice. Results NIS expression was detected on the membrane of two cell lines as early as 6 h after transfection and gradually decreased over 48 h. In vivo and ex vivo PET/MRI of anionic spleen-targeting or cationic lung-targeting NIS-RNA lipoplexes revealed a visually detectable rapid increase of Iodine-124 uptake in the spleen or lung compared to control-RNA-lipoplexes, respectively, with minimal background in other organs except from thyroid, stomach and salivary gland. Conclusions The strong organ selectivity and high target-to-background acquisition of NIS-RNA lipoplexes indicate the feasibility of small animal PET/MRI to quantify organ-specific delivery of RNA.

scholarly journals Preclinical and clinical study on [18F]DRKXH1: a novel β-amyloid PET tracer for Alzheimer’s disease

2021 ◽  
Author(s):  
MiaoMiao Xu ◽  
Jun Guo ◽  
JiaCheng Gu ◽  
LinLin Zhang ◽  
ZiHao Liu ◽  
...  
Keyword(s):  
Transgenic Mice ◽  
Ex Vivo ◽  
Small Animal ◽  
Small Animal Pet ◽  
Animal Pet ◽  
In Vitro Autoradiography ◽  
Healthy Control ◽  
The Brain

Abstract Background The deposition of β-amyloid (Aβ) in the brain is a biomarker of Alzheimer’s disease (AD). Highly sensitive Aβ positron emission tomography (PET) imaging plays an essential role in diagnosing and evaluating the therapeutic effects of AD. Aim To synthesize a new Aβ tracer [18F]DRKXH1 (5-(4-(6-(2-[18]fluoroethoxy)ethoxy)imidazo[1,2-alpha]pyridin-2-yl)phenyl) and evaluate the tracer performance by biodistribution analysis, in vivo small-animal PET-CT dynamic scan, ex vivo and in vitro autoradiography, and PET in human subjects. Methods [18F]DRKXH1 was synthesized automatically by the GE FN module. Log D (pH 7.4) and biodistribution of [18F]DRKXH1 were investigated. Small-animal-PET was used for [18F]DRKXH1 and [18F]AV45 imaging study in AD transgenic mice (APPswe/PSEN1dE9) and age-matched normal mice. The distribution volume ratios (DVR) and standardized uptake value ratios (SUVRs) were calculated with the cerebellum as the reference region. The deposition of Aβ plaques in the brain of AD transgenic mice was determined by ex vivo autoradiography and immunohistochemistry. In vitro autoradiography was performed in the postmortem brain sections of AD patients and healthy controls. Two healthy control subjects and one AD patient was subjected to in vivo PET study using [18F]DRKXH1. Results The yield of [18F]DRKXH1 was 40%, and the specific activity was 156.64 ± 11.55 GBq/μmol. [18F]DRKXH1 was mainly excreted through the liver and kidney. The small-animal PET study showed high initial brain uptake and rapid washout of [18F]DRKXH1. The concentration of [18F]DRKXH1 was detected in the cortex and hippocampus of AD transgenic mice brain. The cortex DVR of AD transgenic mice was higher than that of WT mice (P < 0.0001). Moreover, the SUVRs of AD transgenic mice were higher than those of WT mice based on the 0–60-min dynamic scanning. In vitro autoradiography showed a significant concentration of tracer in the Aβ plaque-rich areas in the brain of AD transgenic mice. The DVR value of [18F]-DRKXH1 is higher than that of [18F]-AV45 (1.29 ± 0.05 vs. 1.05 ± 0.08; t = 5.33, P = 0.0003). Autoradiography of postmortem human brain sections showed [18F]DRKXH1-labeled Aβ plaques in the AD brain. The AD patients had high retention in cortical regions, while healthy control subjects had uniformly low radioactivity uptake. Conclusions [18F]DRKXH1 is an Aβ tracer with high sensitivity in preclinical study and has the potential for in vivo detection of the human brain.

scholarly journals Translational Development of a Zr-89-Labeled Inhibitor of Prostate-specific Membrane Antigen for PET Imaging in Prostate Cancer

2021 ◽  
Author(s):  
Sergio Muñoz Vázquez ◽  
Heike Endepols ◽  
Thomas Fischer ◽  
Samir-Ghali Tawadros ◽  
Melanie Hohberg ◽  
...  
Keyword(s):  
Pet Imaging ◽  
Biochemical Recurrence ◽  
Small Animal ◽  
Small Animal Pet ◽  
Prostate Specific Membrane Antigen ◽  
Tumor Xenografts ◽  
Time Points ◽  
Specific Membrane

Abstract Purpose We present here a Zr-89-labeled inhibitor of prostate-specific membrane antigen (PSMA) as a complement to the already established F-18- or Ga-68-ligands. Procedures The precursor PSMA-DFO (ABX) was used for Zr-89-labeling. This is not an antibody, but a peptide analogue of the precursor for the production of [177Lu]Lu-PSMA-617. The ligand [89Zr]Zr-PSMA-DFO was compared with [68Ga]Ga-PSMA-11 and [18F]F-JK-PSMA-7 in vitro by determination of the Kd value, cellular uptake, internalization in LNCaP cells, biodistribution studies with LNCaP prostate tumor xenografts in mice, and in vivo by small-animal PET imaging in LNCaP tumor mouse models. A first-in-human PET was performed with [89Zr]Zr-PSMA-DFO on a patient presenting with a biochemical recurrence after brachytherapy and an ambiguous intraprostatic finding with [18F]F-JK-PSMA-7 but histologically benign cells in a prostate biopsy 7 months previously. Results [89Zr]Zr-PSMA-DFO was prepared with a radiochemical purity ≥ 99.9% and a very high in vitro stability for up to 7 days at 37 °C. All radiotracers showed similar specific cellular binding and internalization, in vitro and comparable tumor uptake in biodistribution experiments during the first 5 h. The [89Zr]Zr-PSMA-DFO achieved significantly higher tumor/background ratios in LNCaP tumor xenografts (tumor/blood: 309 ± 89, tumor/muscle: 450 ± 38) after 24 h than [68Ga]Ga-PSMA-11 (tumor/blood: 112 ± 57, tumor/muscle: 58 ± 36) or [18F]F-JK-PSMA-7 (tumor/blood: 175 ± 30, tumor/muscle: 114 ± 14) after 4 h (p < 0.01). Small-animal PET imaging demonstrated in vivo that tumor visualization with [89Zr]Zr-PSMA-DFO is comparable to [68Ga]Ga-PSMA-11 or [18F]F-JK-PSMA-7 at early time points (1 h p.i.) and that PET scans up to 48 h p.i. clearly visualized the tumor at late time points. A late [89Zr]Zr-PSMA-DFO PET scan on a patient with biochemical recurrence (BCR) had demonstrated intensive tracer accumulation in the right (SUVmax 13.25, 48 h p.i.) and in the left prostate lobe (SUV max 9.47), a repeat biopsy revealed cancer cells on both sides. Conclusion [89Zr]Zr-PSMA-DFO is a promising PSMA PET tracer for detection of tumor areas with lower PSMA expression and thus warrants further clinical evaluation.

Evaluation of A Novel GLP-1R Ligand for PET Imaging of Prostate Cancer

2019 ◽  
Vol 19 (4) ◽  
pp. 509-514 ◽  
Author(s):  
Yuanyuan Yue ◽  
Yuping Xu ◽  
Lirong Huang ◽  
Donghui Pan ◽  
Zhicheng Bai ◽  
...  
Keyword(s):  
Prostate Cancer ◽  
Pet Imaging ◽  
Ex Vivo ◽  
Xenograft Model ◽  
Small Animal ◽  
Small Animal Pet ◽  
Great Promise ◽  
Western Blots ◽  
Biodistribution Studies

Background:Glucagon-like peptide 1 receptor (GLP-1R) is an important biomarker for diagnosis and therapy of the endocrine cancers due to overexpression. Recently, in human prostate cancer cell lines the receptor was also observed, therefore it may be a potential target for the disease. 18F-Al-NOTA-MAL-Cys39- exendin-4 holds great promise for GLP-1R. Therefore, the feasibility of the 18F-labeled exendin-4 analog for prostate cancer imaging was investigated.Methods:New probe 18F-Al-NOTA-MAL-Cys39-exendin-4 was made through one-step fluorination. Prostate cancer PC3 cell xenograft model mice were established to primarily evaluate the imaging properties of the tracer via small animal PET studies in vivo. Pathological studies and Western Blots were also performed.Results:PC-3 prostate xenografts were clearly imaged under baseline conditions. At 30 and 60 min postinjection, the tumor uptakes were 2.90±0.41%ID/g and 2.26±0.32 %ID/g respectively. The presence of cys39-exendin-4 significantly reduced the tumor uptake to 0.82±0.10 %ID/g at 60 min p.i. Findings of ex vivo biodistribution studies were similar to those of in vivo PET imaging. The tumors to blood and muscles were significantly improved with the increase of time due to rapid clearance of the tracer from normal organs. Low levels of radioactivity were also detected in the GLP-1R positive tumor and normal organs after coinjection with excessive unlabeled peptides. Immunohistochemistry and Western Blots results confirmed that GLP-1R was widely expressed in PC-3 prostate cancers.Conclusion:18F-Al labeled exendin-4 analog might be a promising tracer for in vivo detecting GLP-1R positive prostate cancer with the advantage of facile synthesis and favorable pharmacokinetics. It may be useful in differential diagnosis, molecularly targeted therapy and prognosis of the cancers.

scholarly journals In Vivo Imaging of Peripheral Benzodiazepine Receptors in Mouse Lungs: A Biomarker of Inflammation

2005 ◽  
Vol 4 (4) ◽  
pp. 7290.2005.05133 ◽  
Author(s):  
Matthew J. Hardwick ◽  
Ming-Kai Chen ◽  
Kwamena Baidoo ◽  
Martin G. Pomper ◽  
Tomás R. Guilarte
Keyword(s):  
In Vivo Imaging ◽  
Ex Vivo ◽  
Inflammatory Diseases ◽  
Imaging Techniques ◽  
Benzodiazepine Receptors ◽  
Small Animal ◽  
Small Animal Pet ◽  
Planar Imaging ◽  
Peripheral Benzodiazepine Receptors

The ability to visualize the immune response with radioligands targeted to immune cells will enhance our understanding of cellular responses in inflammatory diseases. Peripheral benzodiazepine receptors (PBR) are present in monocytes and neutrophils as well as in lung tissue. We used lipopolysaccharide (LPS) as a model of inflammation to assess whether the PBR could be used as a noninvasive marker of inflammation in the lungs. Planar imaging of mice administrated 10 or 30 mg/kg LPS showed increased [123I]-( R)-PK11195 radioactivity in the thorax 2 days after LPS treatment relative to control. Following imaging, lungs from control and LPS-treated mice were harvested for ex vivo gamma counting and showed significantly increased radioactivity above control levels. The specificity of the PBR response was determined using a blocking dose of nonradioactive PK11195 given 30 min prior to radiotracer injection. Static planar images of the thorax of nonradioactive PK11195 pretreated animals showed a significantly lower level of radiotracer accumulation in control and in LPS-treated animals ( p < .05). These data show that LPS induces specific increases in PBR ligand binding in the lungs. We also used in vivo small-animal PET studies to demonstrate increased [11C]-( R)-PK11195 accumulation in the lungs of LPS-treated mice. This study suggests that measuring PBR expression using in vivo imaging techniques may be a useful biomarker to image lung inflammation.

Abstract 1767: Feasibility of In Vivo Cardiac Stem Cell Tracking, by SPECT and PET Imaging, Using the Sodium-iodide Symporter as Reporter Gene

Circulation ◽  
2007 ◽  
Vol 116 (suppl_16) ◽  
Author(s):  
John Terrovitis ◽  
Keng Fai Kwok ◽  
Riikka Läutamaki ◽  
James M Engles ◽  
Andreas S Barth ◽  
...  
Keyword(s):  
Stem Cell ◽  
Reporter Gene ◽  
Cell Tracking ◽  
Ex Vivo ◽  
Small Animal ◽  
Cell Labeling ◽  
Sodium Iodide Symporter ◽  
Cell Injection

Background. Stem cells offer the promise of cardiac repair. Stem cell labeling is a prerequisite to tracking cell fate in vivo . Aim. To develop a reporter gene that permits in vivo stem cell labeling. We examined the sodium-iodide symporter (NIS), a protein that is not expressed in the heart, but promotes cellular uptake of 99m Tc or 124 I, thus permitting cell tracking by SPECT or PET imaging, respectively. Methods. The human NIS gene ( h NIS) was expressed in rat cardiac derived stem cells (rCDCs) using lentivirus driven by the CAG or CMV promoter. NIS function in transduced cells was confirmed by in vitro 99m Tc uptake. Eleven rats were injected with 1 or 2 million rCDCs intramyocardially immediately after LAD ligation; 6 with CMV-NIS and 5 with CAG-NIS cells. Dual isotope SPECT imaging was performed on a small animal SPECT/CT system, using 99m Tc for cell detection and 201 Tl for myocardial delineation, 24 hrs after cell injection. PET was performed on a small animal PET scanner using 124 I for cell tracking and 13 NH 3 for myocardial delineation, 48hrs after cell injection. Contrast Ratio (CR) was defined as [(signal in the cells)-(signal in blood pool)]/signal in blood pool. High resolution ex vivo SPECT scans of explanted hearts (n=3) were obtained to confirm that in vivo signal was derived from the cell injection site. The presence of h NIS mRNA was confirmed in injected hearts after animal sacrifice (n=2), by real-time RT-PCR. Results. NIS expression in rCDCs did not affect cell viability/proliferation (p=0.718, ctr vs NIS). In vitro 99m Tc uptake was 6.0±0.9% vs 0.07±0.05, without and with perchlorate (specific NIS blocker), respectively. NIS-transduced rCDCs were easily visualized as spots of 99m Tc or 124 I uptake within a perfusion deficit in the SPECT and PET images. CR was considerably higher when cells were transduced by the CMV-NIS virus in comparison to the CAG-NIS virus (70±40% vs 28±29%, p=0.085). Ex vivo small animal SPECT imaging confirmed that in vivo 99m Tc signals were localized to the injection sites. PCR confirmed the presence of h NIS mRNA in injected hearts. Conclusion. NIS expression allows non invasive in vivo stem cell tracking in the myocardium, using both SPECT and PET. This reporter gene has great potential for translation in future clinical applications.

scholarly journals An in-vitro assay using human spermatozoa to detect toxicity of biologically active substances

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Tino Vollmer ◽  
Börje Ljungberg ◽  
Vera Jankowski ◽  
Joachim Jankowski ◽  
Griet Glorieux ◽  
...  
Keyword(s):  
Ex Vivo ◽  
Toxicity Testing ◽  
Biologically Active ◽  
Human Spermatozoa ◽  
Vitro Assay ◽  
Cellular Behavior ◽  
Novel Method ◽  
Set Up

Abstract Identifying the key toxic players within an in-vivo toxic syndrome is crucial to develop targeted therapies. Here, we established a novel method that characterizes the effect of single substances by means of an ex-vivo incubation set-up. We found that primary human spermatozoa elicit a distinct motile response on a (uremic) toxic milieu. Specifically, this approach describes the influence of a bulk toxic environment (uremia) as well as single substances (uremic toxins) by real-time analyzing motile cellular behavior. We established the human spermatozoa-based toxicity testing (HSTT) for detecting single substance-induced toxicity to be used as a screening tool to identify in-vivo toxins. Further, we propose an application of the HSTT as a method of clinical use to evaluate toxin-removing interventions (hemodialysis).

scholarly journals New 55Co-labeled Albumin-Binding Folate Derivatives as Potential PET Agents for Folate Receptor Imaging

2019 ◽  
Vol 12 (4) ◽  
pp. 166 ◽  
Author(s):  
Lauren L. Radford ◽  
Solana Fernandez ◽  
Rebecca Beacham ◽  
Retta El Sayed ◽  
Renata Farkas ◽  
...  
Keyword(s):  
Folate Receptor ◽  
Small Animal ◽  
Small Animal Pet ◽  
Receptor Imaging ◽  
Albumin Binding ◽  
Liver Uptake ◽  
Biodistribution Studies ◽  
Positron Emission

Overexpression of folate receptors (FRs) on different tumor types (e.g., ovarian, lung) make FRs attractive in vivo targets for directed diagnostic/therapeutic agents. Currently, no diagnostic agent suitable for positron emission tomography (PET) has been adopted for clinical FR imaging. In this work, two 55Co-labeled albumin-binding folate derivatives-[55Co]Co-cm10 and [55Co]Co-rf42-with characteristics suitable for PET imaging have been developed and evaluated. High radiochemical yields (≥95%) and in vitro stabilities (≥93%) were achieved for both compounds, and cell assays demonstrated FR-mediated uptake. Both 55Co-labeled folate conjugates demonstrated high tumor uptake of 17% injected activity per gram of tissue (IA/g) at 4 h in biodistribution studies performed in KB tumor-bearing mice. Renal uptake was similar to other albumin-binding folate derivatives, and liver uptake was lower than that of previously reported [64Cu]Cu-rf42. Small animal PET/CT images confirmed the biodistribution results and showed the clear delineation of FR-expressing tumors.

scholarly journals Improved Detection of Molecular Markers of Atherosclerotic Plaques Using Sub-Millimeter PET Imaging

Molecules ◽  
2020 ◽  
Vol 25 (8) ◽  
pp. 1838 ◽  
Author(s):  
Jessica Bridoux ◽  
Sara Neyt ◽  
Pieterjan Debie ◽  
Benedicte Descamps ◽  
Nick Devoogdt ◽  
...  
Keyword(s):  
Pet Imaging ◽  
Ex Vivo ◽  
High Sensitivity ◽  
Radiochemical Yield ◽  
Control Group ◽  
Complexing Agent ◽  
Atherosclerotic Plaques ◽  
Atherosclerotic Lesions ◽  
Pet Ct

Since atherosclerotic plaques are small and sparse, their non-invasive detection via PET imaging requires both highly specific radiotracers as well as imaging systems with high sensitivity and resolution. This study aimed to assess the targeting and biodistribution of a novel fluorine-18 anti-VCAM-1 Nanobody (Nb), and to investigate whether sub-millimetre resolution PET imaging could improve detectability of plaques in mice. The anti-VCAM-1 Nb functionalised with the novel restrained complexing agent (RESCA) chelator was labelled with [18F]AlF with a high radiochemical yield (>75%) and radiochemical purity (>99%). Subsequently, [18F]AlF(RESCA)-cAbVCAM1-5 was injected in ApoE−/− mice, or co-injected with excess of unlabelled Nb (control group). Mice were imaged sequentially using a cross-over design on two different commercially available PET/CT systems and finally sacrificed for ex vivo analysis. Both the PET/CT images and ex vivo data showed specific uptake of [18F]AlF(RESCA)-cAbVCAM1-5 in atherosclerotic lesions. Non-specific bone uptake was also noticeable, most probably due to in vivo defluorination. Image analysis yielded higher target-to-heart and target-to-brain ratios with the β-CUBE (MOLECUBES) PET scanner, demonstrating that preclinical detection of atherosclerotic lesions could be improved using the latest PET technology.

Sign in / Sign up

Export Citation Format

Share Document