Added Value of Scintillating Element in Cerenkov-Induced Photodynamic Therapy.

Cerenkov-induced photodynamic therapy (CR-PDT) with the use of Gallium-68 (68Ga) as an unsealed radioactive source has been proposed as an alternative strategy to X-ray-induced photodynamic therapy (X-PDT). This new strategy still aims to produce a photodynamic effect with the use of nanoparticles, namely, AGuIX. Recently, we replaced Gd from the AGuIX@ platform with Terbium (Tb) as a nanoscintillator and added 5-(4-carboxyphenyl succinimide ester)-10,15,20-triphenylporphyrin (P1) as a photosensitizer (referred to as AGuIX@Tb-P1). Although Cerenkov luminescence from 68Ga positrons is involved in nanoscintillator and photosensitizer activation, the cytotoxic effect obtained by PDT remains controversial. Herein, we tested whether free 68Ga could substitute X-rays of X-PDT to obtain a cytotoxic phototherapeutic effect. Results were compared with those obtained with AGuIX@Gd-P1 nanoparticles. We showed, by Monte Carlo simulations, the contribution of Tb scintillation in P1 activation by an energy transfer between Tb and P1 after Cerenkov radiation, compared to the Gd-based nanoparticles. We confirmed the involvement of the type II PDT reaction during 68Ga-mediated Cerenkov luminescence, id est, the transfer of photon to AGuIX@Tb-P1 which, in turn, generated P1-mediated singlet oxygen. The effect of 68Ga on cell survival was studied by clonogenic assays using human glioblastoma U-251 MG cells. Exposure of pre-treated cells with AGuIX@Tb-P1 to 68Ga resulted in the decrease in cell clone formation, unlike AGuIX@Gd-P1. We conclude that CR-PDT could be an alternative of X-PDT.

Clickable C-Glycosyl Scaffold for the Development of a Dual Fluorescent and [18F]fluorinated Cyanine-Containing Probe and Preliminary In Vitro/Vivo Evaluation by Fluorescence Imaging.

Considering the individual characteristics of positron emission tomography (PET) and optical imaging (OI) in terms of sensitivity, spatial resolution, and tissue penetration, the development of dual imaging agents for bimodal PET/OI imaging is a growing field. A current major breakthrough in this field is the design of monomolecular agent displaying both a radioisotope for PET and a fluorescent dye for OI. We took advantage of the multifunctionalities allowed by a clickable C-glycosyl scaffold to gather the different elements. We describe, for the first time, the synthesis of a cyanine-based dual PET/OI imaging probe based on a versatile synthetic strategy and its direct radiofluorination via [18F]F-C bond formation. The non-radioactive dual imaging probe coupled with two c(RGDfK) peptides was evaluated in vitro and in vivo in fluorescence imaging. The binding on αvß3 integrin (IC50 = 16 nM) demonstrated the efficiency of the dimeric structure and PEG linkers in maintaining the affinity. In vivo fluorescence imaging of U-87 MG engrafted nude mice showed a high tumor uptake (40- and 100-fold increase for orthotopic and ectopic brain tumors, respectively, compared to healthy brain). In vitro and in vivo evaluations and resection of the ectopic tumor demonstrated the potential of the conjugate in glioblastoma cancer diagnosis and image-guided surgery.

Morcellement du corps et chirurgie bariatrique. De l'organique au corporel dans leur rapport aux logiques structrurelles / Body fragmentation and bariatric surgery. From the organic to the corporeal in their relationship to structural logics / Fragmentação do corpo e cirurgia bariátrica. Do orgânico ao corpóreo em sua relação com a lógica estrutural / Fragmentación corporal y cirurgía bariátrica. De lo orgánico a lo corpóreo en su relación con las lógicas estructurales

Les auteurs, cliniciens et chercheurs en psychopathologie, développent un phénomène psychique transtructurel rencontré chez des patients obèses opérés d'une chirurgie bariatrique: des fantasmes et des délires de morcellement corporel. C'est à partir d'un cas clinique de névrose et un autre de psychose, que l'impact psychique de la chirurgie bariatrique sera étudié, avec la mise en lumière d'une altération de l'image du corps et de ses sensations qui serait à l'origine de ce phénomène de morcellement.

The authors, clinicians, and researchers in psychopathology, developed a trans-structural psychic phenomenon found in obese patients who have undergone bariatric surgery: fantasies and delusions of body fragmentation. The psychic impact of bariatric surgery was studied based on a clinical case of neurosis and another one of psychosis, highlighting an alteration of body image and its sensations which would be at the origin of this phenomenon of fragmentation.

Resumos Os autores, clínicos e pesquisadores em psicopatologia, desenvolvem um fenômeno psíquico transestrutural encontrado em pacientes obesos submetidos à cirurgia bariátrica: fantasias e delírios de fragmentação do corpo. Com base em um caso clínico de neurose e outro de psicose, será estudado o impacto psíquico da cirurgia bariátrica, destacando uma alteração na imagem do corpo e suas sensações, que estariam na origem desse fenômeno de fragmentação.

Los autores, clínicos e investigadores en el campo de la psicopatología, desarrollan un fenómeno psíquico transestructural encontrado en pacientes obesos sometidos a la cirugía bariátrica: fantasías y delirios de fragmentación del cuerpo. Desde un caso clínico de neurosis y otro de psicosis, se estudiará el impacto psíquico de la cirugía bariátrica, destacando una alteración de la imagen corporal y de sus sensaciones, que serían el origen de este fenómeno de fragmentación.

Multi-tracer and multiparametric PET imaging to detect the IDH mutation in glioma: a preclinical translational in vitro, in vivo, and ex vivo study.

BACKGROUND: This translational study explores multi-tracer PET imaging for the non-invasive detection of the IDH1 mutation which is a positive prognostic factor in glioma. METHODS: U87 human high-grade glioma (HGG) isogenic cell lines with or without the IDH1 mutation (CRISP/Cas9 method) were stereotactically grafted into rat brains, and examined, in vitro, in vivo and ex vivo. PET imaging sessions, with radiotracers specific for glycolytic metabolism ([18F]FDG), amino acid metabolism ([18F]FDopa), and inflammation ([18F]DPA-714), were performed sequentially during 3-4 days. The in vitro radiotracer uptake was expressed as percent per million cells. For each radiotracer examined in vivo, static analyses included the maximal and mean tumor-to-background ratio (TBRmax and TBRmean) and metabolic tumor volume (MTV). Dynamic analyses included the distribution volume ratio (DVR) and the relative residence time (RRT) extracted from a reference Logan model. Ex vivo analyses consisted of immunological analyses. RESULTS: In vitro, IDH1+ cells (i.e. cells expressing the IDH1 mutation) showed lower levels of [18F]DPA-714 uptake compared to IDH1- cells (p < 0.01). These results were confirmed in vivo with lower [18F]DPA-714 uptake in IDH+ tumors (3.90 versus 5.52 for TBRmax, p = 0.03). Different values of [18F]DPA-714 and [18F] FDopa RRT (respectively 11.07 versus 22.33 and 2.69 versus - 1.81 for IDH+ and IDH- tumors, p < 0.02) were also observed between the two types of tumors. RRT [18F]DPA-714 provided the best diagnostic performance to discriminate between the two cell lines (AUC of 100%, p < 0.01). Immuno-histological analyses revealed lower expression of Iba-1 and TSPO antibodies in IDH1+ tumors. CONCLUSIONS: [18F]DPA-714 and [18F] FDopa both correlate with the presence of the IDH1 mutation in HGG. These radiotracers are therefore good candidates for translational studies investigating their clinical applications in patients.

Fully Automated Macro- and Microfluidic Production of [68Ga]Ga-Citrate on mAIO® and iMiDEVTM Modules.

68Ga-radionuclide has gained importance due to its availability via 68Ge/68Ga generator or cyclotron production, therefore increasing the number of 68Ga-based PET radiopharmaceuticals available in clinical practice. [68Ga]Ga-citrate PET has been shown to be prominent for detection of inflammation/infection of the musculoskeletal, gastrointestinal, respiratory, and cardiovascular systems. Automation and comparison between conventional and microfluidic production of [68Ga]Ga-citrate was performed using miniAllInOne® (Trasis) and iMiDEV™ (PMB-Alcen) synthetic modules. Fully automated procedures were elaborated for cGMP production of tracer. In order to facilitate the tracer approval as a radiopharmaceutical for clinical use, a new method for radiochemical identity determination by HPLC analysis to complement standard TLC radiochemical purity measurement was developed. The results showed higher radiochemical yields when using MCX cartridge on the conventional module mAIO®, while a PS-H+ cation exchanger was shown to be preferred for integration into the microfluidic cassette of iMiDEV™ module. In this study, the fully automated radiosynthesis of [68Ga]Ga-citrate using different synthesizers demonstrated reliable and reproducible radiochemical yields. In order to demonstrate the applicability of [68Ga]Ga-citrate, in vitro and in vivo studies were performed showing similar characteristics of the tracer obtained using macro- and microfluidic ways of production.

Preliminary Study of New Gallium-68 Radiolabeled Peptide Targeting NRP-1 to Detect Brain Metastases by Positron Emission Tomography.

Due to their very poor prognosis and a fatal outcome, secondary brain tumors are one of the biggest challenges in oncology today. From the point of view of the early diagnosis of these brain micro- and macro-tumors, the sensitivity and specificity of the diagnostic tools constitute an obstacle. Molecular imaging, such as Positron Emission Tomography (PET), is a promising technique but remains limited in the search for cerebral localizations, given the commercially available radiotracers. Indeed, the [18F]FDG PET remains constrained by the physiological fixation of the cerebral cortex, which hinders the visualization of cerebral metastases. Tumor angiogenesis is recognized as a crucial phenomenon in the progression of malignant tumors and is correlated with overexpression of the neuropilin-1 (NRP-1) receptor. Here, we describe the synthesis and the photophysical properties of the new gallium-68 radiolabeled peptide to target NRP-1. The KDKPPR peptide was coupled with gallium-68 anchored into a bifunctional NODAGA chelating agent, as well as Cy5 for fluorescence detection. The Cy5 absorbance spectra did not change, whereas the molar extinction coefficient (ε) decreased drastically. An enhancement of the fluorescence quantum yield (φF) could be observed due to the better water solubility of Cy5. [68Ga]Ga-NODAGA-K(Cy5)DKPPR was radiosynthesized efficiently, presented hydrophilic properties (log D = -1.86), and had high in vitro stability (>120 min). The molecular affinity and the cytotoxicity of this new chelated radiotracer were evaluated in vitro on endothelial cells (HUVEC) and MDA-MB-231 cancer cells (hormone-independent and triple-negative line) and in vivo on a brain model of metastasis in a nude rat using the MDA-MB-231 cell line. No in vitro toxicity has been observed. The in vivo preliminary experiments showed promising results, with a high contrast between the healthy brain and metastatic foci for [68Ga]Ga-NODAGA-K(Cy5)DKPPR.

Implementation of iMiDEV™, a new fully automated microfluidic platform for radiopharmaceutical production.

iMiDEV™ microfluidic system is a new automated tool for a small-scale production of radiopharmaceuticals. This new radiochemistry module utilizes microfluidic cassettes capable of producing diversified radiopharmaceuticals in liquid phase reactions in an automated synthesizer. The user interface is intuitive and designed to give the operator all the information required and to allow driving the synthesis either manually or fully automatically. In this work, we have demonstrated liquid phase reaction and presented the first results of an efficient fully automated [18F]NaF radiosynthesis on the iMiDEV™ platform. Different parameters such as a type of cyclotron targets, initial activity, concentration and volume of the fluoride-18 targetry have been investigated in order to elaborate the optimised radiolabelling of the ligand. Single and double sodium [18F]fluoride synthesis procedures have been successfully developed using two chambers of the cassette. A single-dose of radiotracer was produced in an average radiochemical yield of 87% (decay corrected) within 8 min and quality control tests were performed as per European Pharmacopoeia.

Synthesis of a DOTA-C-glyco bifunctional chelating agent and preliminary in vitro and in vivo study of [68Ga]Ga-DOTA-C-glyco-RGD.

The design of bifunctional chelating agents (BFCA) allowing straightforward radiometal labelling of biomolecules is a current challenge. We report herein the development of a bifunctional chelating agent based on a DOTA chelator linked to a C-glycosyl compound, taking advantage of the robustness and hydrophilicity of this type of carbohydrate derivative. This new BFCA was coupled with success by CuAAC with c(RGDfK) for αvß3 integrin targeting. As attested by in vitro evaluation, the conjugate DOTA-C-glyco-c(RGDfC) demonstrated high affinity for αvß3 integrins (IC50 of 42 nM). [68Ga]Ga-DOTA-C-glyco-c(RGDfK) was radiosynthesized straightforwardly and showed high hydrophilic property (log D 7.4 = -3.71) and in vitro stability (>120 min). Preliminary in vivo PET study of U87MG engrafted mice gave evidence of an interesting tumor-to-non-target area ratio. All these data indicate that [68Ga]Ga-DOTA-C-glyco-c(RGDfK) allows monitoring of αvß3 expression and could thus be used for cancer diagnosis. The DOTA-C-glycoside BFCA reported here could also be used with various ligands and chelating other (radio)metals opening a broad scope of applications in imaging modalities and therapy.

C-glyco"RGD" as αIIbß3 and αvß integrin ligands for imaging applications: Synthesis, in vitro evaluation and molecular modeling.

The design of conjugates displaying simultaneously high selectivity and high affinity for different subtypes of integrins is a current challenge. The arginine-glycine-aspartic acid amino acid sequence (RGD) is one of the most efficient short peptides targeting these receptors. We report herein the development of linear and cyclic fluoro-C-glycoside"RGD" conjugates, taking advantage of the robustness and hydrophilicity of C-glycosides. As attested by in vitro evaluation, the design of these C-glyco"RGD" with a flexible three-carbon triazolyl linker allows distinct profiles towards αIIbß3 and αvß3 integrins. Molecular-dynamics simulations confirm the suitability of cyclic C-glyco-c(RGDfC) to target αvß3 integrin. These C-glyco"RGD" could become promising biological tools in particular for Positron Emission Tomography imaging.

PET imaging of 68Ga-NODAGA-RGD, as compared with 18F-fluorodeoxyglucose, in experimental rodent models of engrafted glioblastoma.

BACKGROUND: Tracers triggering αvß3 integrins, such as certain RGD-containing peptides, were found promising in previous pilot studies characterizing high-grade gliomas. However, only limited comparisons have been performed with current PET tracers. This study aimed at comparing the biodistribution of 18F-fluorodeoxyglucose (18F-FDG) with that of 68Ga-NODAGA-RGD, an easily synthesized monomeric RGD compound with rapid kinetics, in two different rodent models of engrafted human glioblastoma. METHODS: Nude rodents bearing human U87-MG glioblastoma tumor xenografts in the flank (34 tumors in mice) or in the brain (5 tumors in rats) were analyzed. Kinetics of 68Ga-NODAGA-RGD and of 18F-FDG were compared with PET imaging in the same animals, along with additional autohistoradiographic analyses and blocking tests for 68Ga-NODAGA-RGD. RESULTS: Both tracers showed a primary renal route of clearance, although with faster clearance for 68Ga-NODAGA-RGD resulting in higher activities in the kidneys and bladder. The tumor activity from 68Ga-NODAGA-RGD, likely corresponding to true integrin binding (i.e., suppressed by co-injection of a saturating excess of unlabeled RGD), was found relatively high, but only at the 2nd hour following injection, corresponding on average to 53% of total tumor activity. Tumor uptake of 68Ga-NODAGA-RGD decreased progressively with time, contrary to that of 18F-FDG, although 68Ga-NODAGA-RGD exhibited 3.4 and 3.7-fold higher tumor-to-normal brain ratios on average compared to 18F-FDG in mice and rat models, respectively. Finally, ex-vivo analyses revealed that the tumor areas with high 68Ga-NODAGA-RGD uptake also exhibited the highest rates of cell proliferation and αv integrin expression, irrespective of cell density. CONCLUSIONS: 68Ga-NODAGA-RGD has a high potential for PET imaging of glioblastomas, especially for areas with high integrin expression and cell proliferation, although PET recording needs to be delayed until the 2nd hour following injection in order to provide sufficiently high integrin specificity.

Synthesis and preliminary in vivo evaluation of new [18F]fluoro-inositols as Positron Emission Tomography radiotracers.

This study describes the synthesis and radiosynthesis of eight new [18F]fluoro-inositol-based radiotracers in myo- and scyllo-inositol configuration. These radiotracers are equipped with a propyl linker bearing fluorine-18. This fluorinated arm is either on a hydroxyl group, i.e. O-alkylated inositols, or on the cyclohexyl backbone, i.e. C-branched derivatives. To modulate lipophilicity, inositols were synthesized in acetylated or hydroxylated form. Automated radiosynthesis was performed on the AllInOne module and the radiotracers were produced in good radiochemical yields (15-31.5% dc). Preliminary in vivo preclinical evaluation of these eight [18F]fluoro-inositols as Positron Emission Tomography (PET) imaging agents in a breast tumour-bearing mouse model was performed and compared with [18F]-2-fluoro-2-deoxy-d-glucose ([18F]FDG). Amongst the different inositols, [18F]myo-2 showed the highest tumour uptake 2.34±0.39%ID/g, revealing the potential of this tracer for monitoring breast cancer.

Synthesis and revised stereochemical assignment of C-allyl glucopyranosides and derivatives.

α- and ß-C-allylglucopyranosides and hydroxy-, bromo- and azido-derivatives were prepared through allylation at C-1 of methyl 2,3,4,6-tetra-O-benzyl-D-glucopyranoside or 1-O-acetyl-2,3,4,6-tetra-O-benzyl-D-glucopyranose and subsequent chemical modifications of the alkene on the anomeric arm. However, we picked out some discordance between some recent published studies and our results. After a thorough work of characterization and NMR analysis, we unambiguously confirmed α and ß stereochemistry of the two series of compounds and fully described for the first time ß-C-propyl alcohol, bromide and azide of 2,3,4,6-tetra-O-benzyl-D-glucopyranose.

Diastereoselective synthesis of new O-alkylated and C-branched inositols and their corresponding fluoro analogues.

Efficient routes were developed for the diastereoselective synthesis of new O-alkylated and C-branched inositols and their corresponding fluoro analogues. The key steps of the synthesis were the easy accessibility of different types of arms in term of configuration (myo and scyllo), the linking method and length, which could modulate the biological properties. These inositol derivatives, bearing an arm terminated either with a hydroxy group or a fluorine atom, could be interesting candidates for diastereoisomeric intermediates and biological evaluations, especially for PET imaging experiments.

Development of 6-[(18) F]fluoro-carbohydrate-based prosthetic groups and their conjugation to peptides via click chemistry.

This work describes the development of new 6-[(18) F]fluoro-carbohydrate-based prosthetic groups equipped with an azido arm that are able to participate in copper(I)-catalyzed cycloadditions for (18) F labeling of biomolecules under mild conditions. The radiolabeling in high radiochemical yields (up to 68 ± 6%) of these different prosthetic groups is presented. The flexibility of the azido arm introduced on the carbohydrate moieties allows efficient click reactions with different alkyne functionalized peptides such as gluthation or Arg-Gly-Asp derivatives in order to prepare glycopeptides. The radiosyntheses of (18) F-labeled glycopeptides proceed in high radiochemical yields (up to 76%) in an automated process with excellent radiochemical purity. The addition of a sugar moiety on peptides should enhance the bioavailability, pharmacokinetic, and in vivo clearance properties of these glycopeptides, compared with the unlabeled native peptide, and these properties are highly favorable for positron emission tomography imaging. A high uptake of (18) F-ß-gluco-c(RGDfC) is shown by positron emission tomography imaging in a subcutaneous abscess model in the rat, revealing the potential of this tracer to monitor integrin expression as a part of inflammation and/or angiogenesis processes.

Fully automated production of sodium [(18)F]fluoride on AllInOne and miniAllInOne synthesizers.

A fully automated production of the imaging agent sodium [(18)F]fluoride ([(18)F]NaF) on two different modules commercialized by Trasis®, the AllInOne and the miniAllInOne, is reported. Both modules allow to prepare [(18)F]NaF in good radiochemical yield (around 97%) in less than 4min with the same specifications. Quality control of [(18)F]NaF produced by this way was performed according to the US and European Pharmacopeia monograph requirements.

'Click' glycosylation of peptides through cysteine propargylation and CuAAC.

'Click' glycosylation of cysteine-containing peptides were carried out in good yield by Copper(I)-catalyzed Azide-Alkyne Cycloaddition (CuAAC). For that peptides were functionalized though direct propargylation of the cysteine residue allowing their use in CuAAC with suitable free or protected azido sugars of gluco, manno and galacto configuration. Among these free and protected glycopeptides a series of 'glycoRGD' peptides were obtained and submitted to in vitro platelet aggregation tests, showing that the pseudoglycosylation of the adhesion sequence lowers the IC50 value and thus could improve the in vivo pharmacokinetic properties.