Positron Emission Tomography Imaging of Cell Trafficking: A Method of Cell Radiolabeling.

Stem cell and chimeric antigen receptor (CAR) T-cell therapies are emerging as promising therapeutics for organ regeneration and as immunotherapy for various cancers. Despite significant progress having been made in these areas, there is still more to be learned to better understand the pharmacokinetics and pharmacodynamics of the administered therapeutic cells in the living system. For noninvasive, in vivo tracking of cells with positron emission tomography (PET), a novel [Zr]Zr-p-isothiocyanatobenzyl-desferrioxamine ([Zr]Zr-DBN)-mediated cell radiolabeling method has been developed utilizing Zr (t1/2 78.

Design, Synthesis, and Preliminary Evaluation of [Ga]Ga-NOTA-Insulin as a PET Probe in an Alzheimer's Disease Mouse Model.

Aberrant insulin signaling has been considered one of the risk factors for the development of Alzheimer's disease (AD) and has drawn considerable attention from the research community to further study its role in AD pathophysiology. Herein, we describe the development of an insulin-based novel positron emission tomography (PET) probe, [Ga]Ga-NOTA-insulin, to noninvasively study the role of insulin in AD. The developed PET probe [Ga]Ga-NOTA-insulin showed a significantly higher uptake (0.

A new solid target design for the production of Zr and radiosynthesis of high molar activity [Zr]Zr-DBN.

Due to the advent of various biologics like antibodies, proteins, cells, viruses, and extracellular vesicles as biomarkers for disease diagnosis, progression, and as therapeutics, there exists a need to have a simple and ready to use radiolabeling synthon to enable noninvasive imaging trafficking studies. Previously, we reported [Zr]zirconium--isothiocyanatobenzyl-desferrioxamine ([Zr]Zr-DBN) as a synthon for the radiolabeling of biologics to allow PET imaging of cell trafficking. In this study, we focused on improving the molar activity (A) of [Zr]Zr-DBN, by enhancing Zr production on a low-energy cyclotron and developing a new reverse phase HPLC method to purify [Zr]Zr-DBN.

Dynamic Imaging of Chimeric Antigen Receptor T Cells with [18F]Tetrafluoroborate Positron Emission Tomography/Computed Tomography.

T cells genetically engineered to express chimeric antigen receptors (CAR) have shown unprecedented results in pivotal clinical trials for patients with B cell malignancies or multiple myeloma (MM). However, numerous obstacles limit the efficacy and prohibit the widespread use of CAR T cell therapies due to poor trafficking and infiltration into tumor sites as well as lack of persistence in vivo. Moreover, life-threatening toxicities, such as cytokine release syndrome or neurotoxicity, are major concerns.

Corrigendum: Evaluation of Zn, Cu, and Se Levels in the North American Autism Spectrum Disorder Population.

[This corrects the article DOI: 10.3389/fnmol.2021.

Development of a Clinically Relevant Reporter for Chimeric Antigen Receptor T-cell Expansion, Trafficking, and Toxicity.

Although chimeric antigen receptor T (CART)-cell therapy has been successful in treating certain hematologic malignancies, wider adoption of CART-cell therapy is limited because of minimal activity in solid tumors and development of life-threatening toxicities, including cytokine release syndrome (CRS). There is a lack of a robust, clinically relevant imaging platform to monitor expansion and trafficking to tumor sites. To address this, we utilized the sodium iodide symporter (NIS) as a platform to image and track CART cells.

Non-invasive immunoPET imaging of PD-L1 using anti-PD-L1-B11 in breast cancer and melanoma tumor model.

Introduction: Immunotherapy targeting PD-1/PD-L1 immune checkpoint inhibition (ICI) is efficacious in various solid and hematologic malignancies. However, the response rate to PD-1/PD-L1 therapy is only 15-35%. To obtain optimal clinical response to ICI therapies, a reliable assessment of tumor PD-L1 expression is needed to select appropriate patients, and a non-invasive imaging-based assessment of PD-L1 expression is critically needed.

Evaluation of Zn, Cu, and Se Levels in the North American Autism Spectrum Disorder Population.

Metal ion dyshomeostasis and disparate levels of biometals like zinc (Zn), copper (Cu), and selenium (Se) have been implicated as a potential causative factor for Autism Spectrum Disorder (ASD). In this study, we have enrolled 129 children (aged 2-4 years) in North America, of which 64 children had a diagnosis of ASD and 65 were controls. Hair, nail, and blood samples were collected and quantitatively analyzed for Zn, Cu and Se using inductively coupled plasma mass spectrometry (ICP-MS).

[Zr]Zr-DBN labeled cardiopoietic stem cells proficient for heart failure.

Introduction: Radiolabeling of stem cells with a positron emitting radioisotope represents a major advancement in regenerative biotherapy enabling non-invasive imaging. To assess the value of such an approach in a clinically relevant scenario, the tolerability and therapeutic aptitude of [Zr]zirconium-p-isothiocyanatobenzyl-desferrioxamine ([Zr]Zr-DBN) labeled human cardiopoietic stem cells (CPs) were evaluated in a model of ischemic heart failure.

Methods And Results: [Zr]Zr-DBN based radiolabeling of human CPs yielded [Zr]Zr-DBN-CPs with radioactivity yield of 0.

Cell Therapy by Ectopic Hepatocyte Transplantation Treats the Porcine Tyrosinemia Model of Acute Liver Failure.

The effectiveness of cell-based therapies to treat liver failure is often limited by the diseased liver environment. Here, we provide preclinical proof of concept for hepatocyte transplantation into lymph nodes as a cure for liver failure in a large-animal model with hereditary tyrosinemia type 1 (HT1), a metabolic liver disease caused by deficiency of fumarylacetoacetate hydrolase (FAH) enzyme. Autologous porcine hepatocytes were transduced with a lentiviral vector carrying the pig gene and transplanted into mesenteric lymph nodes.

Cyclotron Production of PET Radiometals in Liquid Targets: Aspects and Prospects.

The present review describes the methodological aspects and prospects of the production of Positron Emission Tomography (PET) radiometals in a liquid target using low-medium energy medical cyclotrons. The main objective of this review is to delineate and discuss the critical factors involved in the liquid target production of radiometals, including type of salt solution, solution composition, beam energy, beam current, the effect of irradiation duration (length of irradiation) and challenges posed by in-target chemistry in relation with irradiation parameters. We also summarize the optimal parameters for the production of various radiometals in liquid targets.

Catechol-Based Functionalizable Ligands for Gallium-68 Positron Emission Tomography Imaging.

Four tris-bidentate catecholamide (CAM) ligands were synthesized, characterized, and evaluated as ligands for radiolabeling of gallium-68 for positron emission tomography (PET). Three of those ligands, 2,2-Glu-CAM, 3,3-Glu-CAM, and TREN-bisGlyGlu-CAM, incorporate ligand caps that contain a pendant carboxylic group for further conjugation to targeting moieties. The acyclic ligands all exhibited high (>80%) radiolabeling yields after short reaction times (<10 min) at room temperature, a distinct advantage over macrocyclic analogues that display slower kinetics.

Dual-Isotope SPECT Imaging with NIS Reporter Gene and Duramycin to Visualize Tumor Susceptibility to Oncolytic Virus Infection.

Noninvasive dual-imaging methods that provide an early readout on tumor permissiveness to virus infection and tumor cell death could be valuable in optimizing development of oncolytic virotherapies. Here, we have used the sodium iodide symporter (NIS) and I radiotracer to detect infection and replicative spread of an oncolytic vesicular stomatitis virus (VSV) in VSV-susceptible (MPC-11 tumor) versus VSV-resistant (CT26 tumor) tumors in BALB/c mice. In conjunction, tumor cell death was imaged simultaneously using technetium (Tc)-duramycin that binds phosphatidylethanolamine in apoptotic and necrotic cells.

Radiation induced oxidation of [F]fluorothia fatty acids under cGMP manufacturing conditions.

Objective: The objectives of the present work were to optimize and validate the synthesis and stability of 14(R,S)-[F]fluoro-6-thia-heptadecanoic acid ([F]FTHA) and 16-[F]fluoro-4-thia-palmitic acid ([F]FTP) under cGMP conditions for clinical applications.

Methods: Benzyl-14-(R,S)-tosyloxy-6-thiaheptadecanoate and methyl 16-bromo-4-thia-palmitate were used as precursors for the synthesis of [F]FTHA and [F]FTP, respectively. For comparison, a fatty acid analog lacking a thia-substitution, 16-[F]fluoro-palmitic acid ([F]FP), was synthesized from the precursor methyl 16-bromo-palmitate.

Cyclotron production of Ga in a liquid target: Effects of solution composition and irradiation parameters.

Objectives: To optimize Ga production using a liquid cyclotron target, investigations were performed to compare production yields using different concentrations of [Zn]Zn(NO), nitric acid, and irradiation parameters.

Methods: Different concentrations of [Zn]Zn(NO) (0.6 M, 1.

Enhanced noninvasive imaging of oncology models using the NIS reporter gene and bioluminescence imaging.

Noninvasive bioluminescence imaging (BLI) of luciferase-expressing tumor cells has advanced pre-clinical evaluation of cancer therapies. Yet despite its successes, BLI is limited by poor spatial resolution and signal penetration, making it unusable for deep tissue or large animal imaging and preventing precise anatomical localization or signal quantification. To refine pre-clinical BLI methods and circumvent these limitations, we compared and ultimately combined BLI with tomographic, quantitative imaging of the sodium iodide symporter (NIS).

Cloning, function, and localization of human, canine, and Drosophila ZIP10 (SLC39A10), a Zn transporter.

Zinc (Zn) is the second most abundant trace element, but is considered a micronutrient, as it is a cofactor for many enzymes and transcription factors. Whereas Zn deficiency can cause cognitive immune or metabolic dysfunction and infertility, excess Zn is nephrotoxic. As for other ions and solutes, Zn is moved into and out of cells by specific membrane transporters: ZnT, Zip, and NRAMP/DMT proteins.

Noninvasive evaluation of fat-carbohydrate metabolic switching in heart and contracting skeletal muscle.

The ability of heart and skeletal muscle (SM) to switch between fat and carbohydrate oxidation is of high interest in the study of metabolic diseases and exercise physiology. Positron emission tomography (PET) imaging with the glucose analog 2-[F]fluoro-2-deoxy-glucose (F-FDG) provides a noninvasive means to quantitate glucose metabolic rates. However, evaluation of fatty acid oxidation (FAO) rates by PET has been limited by the lack of a suitable FAO probe.

New transgenic NIS reporter rats for longitudinal tracking of fibrogenesis by high-resolution imaging.

Fibrogenesis is the underlying mechanism of wound healing and repair. Animal models that enable longitudinal monitoring of fibrogenesis are needed to improve traditional tissue analysis post-mortem. Here, we generated transgenic reporter rats expressing the sodium iodide symporter (NIS) driven by the rat collagen type-1 alpha-1 (Col1α1) promoter and demonstrated that fibrogenesis can be visualized over time using SPECT or PET imaging following activation of NIS expression by rotator cuff (RC) injury.

[F]Tetrafluoroborate ([F]TFB) and its analogs for PET imaging of the sodium/iodide symporter.

Sodium/iodide symporter (NIS)-mediated iodide uptake in thyroid follicular cells is the basis of clinical utilization of radioiodines. The cloning of the NIS gene enabled applications of NIS as a reporter gene in both preclinical and translational research. Non-invasive NIS imaging with radioactive iodides and iodide analogs has gained much interest in recent years for evaluation of thyroid cancer and NIS reporter expression.

Hepatocyte spheroids as an alternative to single cells for transplantation after ex vivo gene therapy in mice and pig models.

Background: Autologous hepatocyte transplantation after ex vivo gene therapy is an alternative to liver transplantation for metabolic liver disease. Here we evaluate ex vivo gene therapy followed by transplantation of single-cell or spheroid hepatocytes.

Methods: Pig and mouse hepatocytes were isolated, labeled with zirconium-89 and returned to the liver as single cells or spheroids.

Reassessment of the Transport Mechanism of the Human Zinc Transporter SLC39A2.

The human zinc transporter SLC39A2, also known as ZIP2, was shown to mediate zinc transport that could be inhibited at pH <7.0 and stimulated by HCO, suggesting a Zn/HCO cotransport mechanism [Gaither, L. A.

Synthesis and evaluation of F-hexafluorophosphate as a novel PET probe for imaging of sodium/iodide symporter in a murine C6-glioma tumor model.

Noninvasive imaging of iodide uptake via the sodium/iodide symporter (NIS) has received great interest for evaluation of thyroid cancer and reporter imaging of NIS-expressing viral therapies. In this study, we investigate F-labeled hexafluorophosphate (HFP or PF) as a high-affinity iodide analog for NIS imaging. F-HFP was synthesized by radiofluorination of phosphorus pentafluoride·N-methylpyrrolidine complex and evaluated in human NIS (hNIS)-expressing C6 glioma cells and a C6 glioma xenograft mouse model.

Safety, pharmacokinetics, metabolism and radiation dosimetry of F-tetrafluoroborate (F-TFB) in healthy human subjects.

Background: F-Tetrafluoroborate (F-TFB) is a promising iodide analog for PET imaging of thyroid cancer and sodium/iodide symporter (NIS) reporter activity in viral therapy applications. The aim of this study was to evaluate the safety, pharmacokinetics, biodistribution, and radiation dosimetry of high-specific activity F-TFB in healthy human subjects.

Methods: F-TFB was synthesized with specific activity of 3.

First PET Imaging Studies With 63Zn-Zinc Citrate in Healthy Human Participants and Patients With Alzheimer Disease.

Abnormalities in zinc homeostasis are indicated in many human diseases, including Alzheimer disease (AD). Zn-zinc citrate was developed as a positron emission tomography (PET) imaging probe of zinc transport and used in a first-in-human study in 6 healthy elderly individuals and 6 patients with clinically confirmed AD. Dynamic PET imaging of the brain was performed for 30 minutes following intravenous administration of Zn-zinc citrate (∼330 MBq).