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The aggregation of ß-amyloid peptides is associated to neurodegeneration in Alzheimer's disease (AD) patients. Consequently, the inhibition of both oligomerization and fibrillation of ß-amyloid peptides is considered a plausible therapeutic approach for AD. Herein, the synthesis of new naphthalene derivatives and their evaluation as anti-ß-amyloidogenic agents are presented. Molecular dynamic simulations predicted the formation of thermodynamically stable complexes between the compounds, the Aß1-42 peptide and fibrils. In human microglia cells, these compounds inhibited the aggregation of Aß1-42 peptide. The lead compound 8 showed a high affinity to amyloid plaques in mice brain ex vivo assays and an adequate log Poct/PBS value. Compound 8 also improved the cognitive function and decreased hippocampal ß-amyloid burden in the brain of 3xTg-AD female mice. Altogether, our results suggest that 8 could be a novel therapeutic agent for AD.
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Doença de Alzheimer/tratamento farmacológico , Peptídeos beta-Amiloides/antagonistas & inibidores , Naftalenos/farmacologia , Fármacos Neuroprotetores/farmacologia , Fragmentos de Peptídeos/antagonistas & inibidores , Agregados Proteicos/efeitos dos fármacos , Agregação Patológica de Proteínas/tratamento farmacológico , Doença de Alzheimer/metabolismo , Peptídeos beta-Amiloides/metabolismo , Animais , Astrócitos/efeitos dos fármacos , Astrócitos/metabolismo , Relação Dose-Resposta a Droga , Camundongos , Camundongos Endogâmicos C57BL , Simulação de Dinâmica Molecular , Estrutura Molecular , Naftalenos/síntese química , Naftalenos/química , Fármacos Neuroprotetores/síntese química , Fármacos Neuroprotetores/química , Fragmentos de Peptídeos/metabolismo , Agregação Patológica de Proteínas/metabolismo , Relação Estrutura-Atividade , TermodinâmicaRESUMO
Objective: The aim of this study was to develop an emulgel for the treatment of rosacea, applying quality by design (QbD).Methods: An emulgel designed to release the active pharmaceutical ingredients (APIs), metronidazole and niacinamide, via an emollient formulation that favors residence time and attenuates facial redness would be an excellent vehicle to develop to treat rosacea. It was decided to design first a vehicle presenting the attributes established in the quality target product profile, and then, after selecting the best formulation, to load the APIs in it to optimize the final emulgel. A design of experiments was introduced to study the effect of formulation variables on quality attributes (adhesion, phase separation by mechanical stress and viscosity) of the emulgels. Response surface methodology and desirability functions were applied for data analysis. After optimization, the final emulgel was further characterized by assay and in vitro release of APIs, attenuation of facial redness, and compared to commercially available metronidazole products regarding API release.Results: The final emulgel gradually released both APIs, reaching approximately 88% within the first 4 h, and their profiles were well described by the Higuchi model. Only a light attenuation effect to conceal facial redness was achieved.Conclusions: A metronidazole and niacinamide emulgel, also providing cosmetic assistance, was developed using QbD. The emulgel releases metronidazole faster than the creams, but more gradually than the commercially available gel, providing a realistic time frame of drug delivery in accordance with the expected time of residence of the adhesive emulgel over the affected facial area.
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Géis/administração & dosagem , Géis/química , Rosácea/tratamento farmacológico , Química Farmacêutica/métodos , Cosméticos/administração & dosagem , Cosméticos/química , Sistemas de Liberação de Medicamentos/métodos , Liberação Controlada de Fármacos , Excipientes/química , Humanos , Metronidazol/administração & dosagem , Metronidazol/química , Niacinamida/administração & dosagem , Niacinamida/química , Viscosidade/efeitos dos fármacosRESUMO
The development of new radiopharmaceuticals for the detection of hidden infection foci has great relevance for early detection and the selection of the correct treatment, particularly in immunosuppressed patients. In that sense, the labelling of antimicrobial peptides (AMPs) that are capable of binding specifically to the pathogenic microorganism which causes the infection, should provide a sufficiently specific agent, able to distinguish an infection from a sterile inflammation. Defensins are particularly interesting molecules with antimicrobial activity, the EcgDf1 defensin was identified from the genome of a Uruguayan native plant, Erythrina crista-galli, the 'Ceibo' tree. Our group has previously reported a synthetic biologically active short analogue EcgDf21 (ERFTGGHCRGFRRRCFCTKHC) successfully labelled with 99mTc. Herein we present a shorter analogue which also preserves the γ-core domain, as a pharmacophore for a potential infection detection agent. This peptide was derivatized with the bifunctional chelating agent 1,4,7-triazacyclononane-1,4,7-triacetic acid (NOTA) through a lysine linker in the amino-terminal group (NOTA-KGHCRGFRRRC) and radiolabelled with 68Ga ([68Ga]Ga-NOTA-K-EcgDf1(10)). The [68Ga]Ga-NOTA-K-EcgDf1(10) labelling procedure rendered a product with high radiochemical purity and stability in the labelling milieu. The Log P value indicated that the complex has a hydrophilic behaviour, confirmed by the biodistribution profile. The [68Ga]Ga-NOTA-K-EcgDf1(10) complex demonstrated specific binding to cultures of Candida albicans and Aspergillus niger. Its biodistribution showed renal elimination and low accumulation in the rest of the body. It was possible to successfully differentiate sterile inflammation from infection by PET images in nude mice with a target/non-target ratio of 3.3 for C. albicans and 3.7 for A. niger, respectively.
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Defensinas , Radioisótopos de Gálio , Tomografia por Emissão de Pósitrons , Compostos Radiofarmacêuticos , Animais , Humanos , Camundongos , Sequência de Aminoácidos , Defensinas/química , Radioisótopos de Gálio/química , Peptídeos/química , Tomografia por Emissão de Pósitrons/métodos , Compostos Radiofarmacêuticos/química , Distribuição Tecidual , Compostos de Organotecnécio/químicaRESUMO
BACKGROUND: Angiogenesis is a process that many tumors depend on for growth, development, and metastasis. Vascular endothelial growth factor (VEGF) is one of the major players in tumor angiogenesis in several tumor types, including melanoma. VEGF inhibition is achieved by bevacizumab, a humanized monoclonal antibody that binds with high affinity to VEGF and prevents its function. In order to successfully enable in vivo VEGF expression imaging in a murine melanoma model, we previously labeled bevacizumab with [99mTc]Tc. We observed that this was feasible, but it had prolonged blood circulation and delayed tumor uptake. OBJECTIVE: The aim of this study was to develop a radiolabeled Fab bevacizumab fragment, [99mTc]Tc-HYNICFab( bevacizumab), for non-invasive in vivo VEGF expression molecular imaging. METHODS: Flow cytometry was used to examine VEGF presence in the murine melanoma cell line (B16-F10). Bevacizumab was digested with papain for six hours at 37°C to produce Fab(bevacizumab), which was then conjugated to NHS-HYNIC-Tfa for radiolabeling with [99mTc]Tc. Stability and binding affinity assays were also evaluated. Biodistribution and single photon emission computed tomography/computed tomography (SPECT/CT) were performed at 1, 3, and 6 h (n = 4) after injection of [99mTc]Tc-HYNIC-Fab(Bevacizumab) in normal and B16-F10 tumor-bearing C57Bl/6J mice. RESULTS: Using flow cytometry, it was shown that the B16-F10 murine melanoma cell line has intracellular VEGF expression. Papain incubation resulted in the complete digestion of bevacizumab with good purity and homogeneity. The radiolabeling yield of [99mTc]Tc-HYNIC-Fab(bevacizumab) was 85.00 ± 6.06%, with a specific activity of 291.87 ± 18.84 MBq/mg (n=3), showing in vitro stability. Binding assays demonstrated significant intracellular in vitro VEGF expression. Fast blood clearance and high kidney and tumor uptake were observed in biodistribution and SPECT/CT studies. CONCLUSIONS: We present the development and evaluation of [99mTc]Tc-HYNIC-Fab(bevacizumab), a novel molecular VEGF expression imaging agent that may be used for precision medicine in melanoma and potentially in other VEGF-expressing tumors.
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Alzheimer's disease (AD) involves a neurodegenerative process that has not yet been prevented, reversed, or stopped. Continuing with the search for natural pharmacological treatments, flavonoids are a family of compounds with proven neuroprotective effects and multi-targeting behavior. The American genus Dalea L. (Fabaceae) is an important source of bioactive flavonoids. In this opportunity, we tested the neuroprotective potential of three prenylated flavanones isolated from Dalea species in a new in vitro pre-clinical AD model previously developed by us. Our approach consisted in exposing neural cells to conditioned media (3xTg-AD ACM) from neurotoxic astrocytes derived from hippocampi and cortices of old 3xTg-AD mice, mimicking a local neurodegenerative microenvironment. Flavanone 1 and 3 showed a neuroprotective effect against 3xTg-AD ACM, being 1 more active than 3. The structural requirements to afford neuroprotective activity in this model are a 5'-dimethylallyl and 4'-hydroxy at the B ring. In order to search the mechanistic performance of the most active flavanone, we focus on the flavonoid-mediated regulation of GSK-3ß-mediated tau phosphorylation previously reported. Flavanone 1 treatment decreased the rise of hyperphosphorylated tau protein neuronal levels induced after 3xTg-AD ACM exposure and inhibited the activity of GSK-3ß. Finally, direct exposure of these neurotoxic 3xTg-AD astrocytes to flavanone 1 resulted in toxicity to these cells and reduced the neurotoxicity of 3xTg-AD ACM as well. Our results allow us to present compound 1 as a natural prenylated flavanone that could be used as a precursor to development and design of future drug therapies for AD.
Assuntos
Doença de Alzheimer , Flavanonas , Fármacos Neuroprotetores , Camundongos , Animais , Doença de Alzheimer/tratamento farmacológico , Doença de Alzheimer/metabolismo , Glicogênio Sintase Quinase 3 beta/metabolismo , Camundongos Transgênicos , Proteínas tau/metabolismo , Flavanonas/farmacologia , Flavanonas/uso terapêutico , Fármacos Neuroprotetores/farmacologia , Fármacos Neuroprotetores/uso terapêutico , Modelos Animais de Doenças , Fosforilação , Peptídeos beta-Amiloides/metabolismoRESUMO
Neurodegenerative diseases such as Alzheimer's disease have been classically studied from a purely neuronocentric point of view. More recent evidences support the notion that other cell populations are involved in disease progression. In this sense, the possible pathogenic role of glial cells like astrocytes is increasingly being recognized. Once faced with tissue damage signals and other stimuli present in disease environments, astrocytes suffer many morphological and functional changes, a process referred as reactive astrogliosis. Studies from murine models and humans suggest that these complex and heterogeneous responses could manifest as disease-specific astrocyte phenotypes. Clear understanding of disease-associated astrocytes is a necessary step to fully disclose neurodegenerative processes, aiding in the design of new therapeutic and diagnostic strategies. In this work, we present the transcriptomics characterization of neurotoxic astrocytic cultures isolated from adult symptomatic animals of the triple transgenic mouse model of Alzheimer's disease (3xTg-AD). According to the observed profile, 3xTg-AD neurotoxic astrocytes show various reactivity features including alteration of the extracellular matrix and release of pro-inflammatory and proliferative factors that could result in harmful effects to neurons. Moreover, these alterations could be a consequence of stress responses at the endoplasmic reticulum and mitochondria as well as of concomitant metabolic adaptations. Present results support the hypothesis that adaptive changes of astrocytic function induced by a stressed microenvironment could later promote harmful astrocyte phenotypes and further accelerate or induce neurodegenerative processes.
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Doença de Alzheimer , Humanos , Camundongos , Animais , Doença de Alzheimer/metabolismo , Camundongos Transgênicos , Astrócitos/metabolismo , Transcriptoma , Modelos Animais de DoençasRESUMO
The role of monoamine oxidase A (MAO-A) in the aggressiveness of prostate cancer (PCa) has been established in recent years. The molecular imaging of MAO-A expression could offer a noninvasive tool for the visualization and quantification of highly aggressive PCa. This study reports the synthesis and preclinical evaluation of 11C- and 18F-labeled MAO-A inhibitors as positron emission tomography (PET) tracers for proof-of-concept studies in animal models of PCa. Good manufacturing practice production and quality control of these radiotracers using an automated platform was achieved. PET imaging was performed in an LNCaP tumor model with high MAO-A expression. The tumor-to-muscle (T/M) uptake ratio of [11C]harmine (4.5 ± 0.5) was significantly higher than that for 2-[18F]fluoroethyl-harmol (2.3 ± 0.7) and [11C]clorgyline (2.0 ± 0.1). A comparable ex vivo biodistribution pattern in all radiotracers was observed. Furthermore, the tumor uptake of [11C]harmine showed a dramatic reduction (T/M = 1) in a PC3 tumor model with limited MAO-A expression, and radioactivity uptake in LNCaP tumors was blocked in the presence of nonradioactive harmine. Our findings suggest that [11C]harmine may serve as an attractive PET probe for the visualization of MAO-A expression in highly aggressive PCa. These radiotracers have the potential for clinical translation and may aid in the development of personalized therapeutic strategies for PCa patients.
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Emerging evidence suggests that immune receptors may participate in many aging-related processes such as energy metabolism, inflammation, and cognitive decline. CD300f, a TREM2-like lipid-sensing immune receptor, is an exceptional receptor as it integrates activating and inhibitory cell-signaling pathways that modulate inflammation, efferocytosis, and microglial metabolic fitness. We hypothesize that CD300f can regulate systemic aging-related processes and ultimately healthy lifespan. We closely followed several cohorts of two strains of CD300f-/- and WT mice of both sexes for 30 months and observed an important reduction in lifespan and healthspan in knockout mice. This was associated with systemic inflammaging, increased cognitive decline, reduced brain glucose uptake observed by 18FDG PET scans, enrichment in microglial aging/neurodegeneration phenotypes, proteostasis alterations, senescence, increased frailty, and sex-dependent systemic metabolic changes. Moreover, the absence of CD300f altered macrophage immunometabolic phenotype. Taken together, we provide strong evidence suggesting that myeloid cell CD300f immune receptor contributes to healthy aging.
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Disfunção Cognitiva , Envelhecimento Saudável , Masculino , Feminino , Camundongos , Animais , Macrófagos/metabolismo , Inflamação/metabolismo , Microglia/metabolismo , Camundongos Knockout , Disfunção Cognitiva/metabolismoRESUMO
Alzheimer's disease has been considered mostly as a neuronal pathology, although increasing evidence suggests that glial cells might play a key role in the disease onset and progression. In this sense, astrocytes, with their central role in neuronal metabolism and function, are of great interest for increasing our understanding of the disease. Thus, exploring the morphological and functional changes suffered by astrocytes along the course of this disorder has great therapeutic and diagnostic potential. In this work we isolated and cultivated astrocytes from symptomatic 9-10-months-old adult 3xTg-AD mice, with the aim of characterizing their phenotype and exploring their pathogenic potential. These "old" astrocytes occurring in the 3xTg-AD mouse model of Alzheimer's Disease presented high proliferation rate and differential expression of astrocytic markers compared with controls. They were neurotoxic to primary neuronal cultures both, in neuronal-astrocyte co-cultures and when their conditioned media (ACM) was added into neuronal cultures. ACM caused neuronal GSK3ß activation, changes in cytochrome c pattern, and increased caspase 3 activity, suggesting intrinsic apoptotic pathway activation. Exposure of neurons to ACM caused different subcellular responses. ACM application to the somato-dendritic domain in compartmentalised microfluidic chambers caused degeneration both locally in soma/dendrites and distally in axons. However, exposure of axons to ACM did not affect somato-dendritic nor axonal integrity. We propose that this newly described old 3xTg-AD neurotoxic astrocytic population can contribute towards the mechanistic understanding of the disease and shed light on new therapeutical opportunities.
Assuntos
Doença de Alzheimer , Síndromes Neurotóxicas , Doença de Alzheimer/metabolismo , Peptídeos beta-Amiloides/metabolismo , Animais , Astrócitos/metabolismo , Modelos Animais de Doenças , Camundongos , Camundongos Transgênicos , Neurônios/metabolismo , Síndromes Neurotóxicas/metabolismoRESUMO
In vivo receptor targeting with radiolabelled peptide-based probes is an attractive approach for the development of novel radiotracers for molecular imaging. This work presents the development and characterization of two novel neuropeptide Y analogues labelled with a positron emitter 68 Ga, for potential use in breast cancer imaging. Both analogues share the same amino acid sequence and were derivatized with NOTA through either a lysine linker (L1) or an acetylated lysine (L2). In both cases, a single product with radiochemical purity higher than 95% was obtained. The two complexes were hydrophilic, showed remarkable in vitro stability, good cellular uptake, binding affinity in the nanomolar range and high cellular internalization rate. Biodistribution studies revealed low blood uptake and elimination through the urinary tract. The addition of an acetyl group in the spacer increased the lipophilicity of C2 and modified the reactivity of the ε-amino group of the lysine which resulted in lower protein binding and lower percentage of injected dose in bladder and urine. The tumour versus muscle ratio was (3.8 ± 0.4) for 68 Ga-L1 and (4.7 ± 0.4) for 68 Ga-L2. These results encourage performing further studies in order to complete the evaluation of both tracers as potential radiopharmaceutical for breast cancer imaging.
Assuntos
Neoplasias da Mama/diagnóstico por imagem , Radioisótopos de Gálio/química , Neuropeptídeo Y/química , Compostos Radiofarmacêuticos/química , Aminas/química , Sequência de Aminoácidos , Animais , Transporte Biológico , Cinerradiografia , Feminino , Humanos , Lisina/química , Camundongos Nus , Neoplasias Experimentais , Neuropeptídeo Y/sangue , Neuropeptídeo Y/farmacocinética , Neuropeptídeo Y/urina , Ligação Proteica , Compostos Radiofarmacêuticos/sangue , Compostos Radiofarmacêuticos/farmacocinética , Compostos Radiofarmacêuticos/urina , Coloração e Rotulagem , Relação Estrutura-Atividade , Distribuição TecidualRESUMO
Neurodegenerative diseases (NDs) represent a global problem on public health, with a growing incidence as human longevity increases. Currently, although there are palliative strategies available for most of these diseases, there is a lack of effective therapies for their cure. Flavonoids are extensively studied for their multi-target behavior. Among numerous biological activities, it has been reported that they act at the CNS level, presenting neuroprotective activity through different mechanisms of action. Dalea L. (Fabaceae) is an American genus, with about 172 species. Dalea elegans Gillies ex. Hook. & Arn and Dalea pazensis Rusby, both South American species, are the important source of natural compounds of the prenylated flavanones type. In the present study, five prenylated flavanones isolated from Dalea species were assayed for their neuroprotective activity in two in vitro models of neurodegeneration. Flavanones 1 and 2 exhibited neuroprotective effects against oxidative stress-induced death in both models, granular cerebellar neurons and (NGF)-differentiated PC12 cells. Structure-activity relationships were also reported. Our results indicated that an 8-prenyl group at the A-ring accompanied by an unsubstituted B-ring, or a 2',4'-dihydroxy-5'-dimethylallyl substitution, lead to the most potent flavanones. Furthermore, in silico studies were performed, and several putative targets in NDs were identified for compounds 1 and 2. Between them, the enzyme acetylcholinesterase was selected for its validation in vitro. The present in vitro and in silico results imply that prenylated flavanones 1 and 2 may be useful in the development and design of future strategies for the treatment of NDs diseases.
Assuntos
Simulação por Computador , Fabaceae/química , Flavanonas/química , Flavanonas/farmacologia , Fármacos Neuroprotetores/química , Fármacos Neuroprotetores/farmacologia , Prenilação , Animais , Diferenciação Celular/efeitos dos fármacos , Flavanonas/isolamento & purificação , Neurônios/citologia , Neurônios/efeitos dos fármacos , Neurônios/metabolismo , Fármacos Neuroprotetores/isolamento & purificação , Estresse Oxidativo/efeitos dos fármacos , Células PC12 , Ratos , Relação Estrutura-AtividadeRESUMO
BACKGROUND: The ß-amyloid radiotracer [11C] PiB is extensively used for the Positron Emission Tomography (PET) diagnosis of Alzheimer's Disease and related dementias. For clinical use, [11C] PiB is produced using the 11C-methylation method ([11C] Methyl iodide or [11C] methyl triflate as 11C-methylation agents), which represents the most employed 11C-labelling strategy for the synthesis of 11C-radiopharmaceuticals. Recently, the use of direct [11C]CO2 fixation for the syntheses of 11C-tracers has gained interest in the radiochemical community due to its importance in terms of radiochemical versatility and for permitting the direct employment of the cyclotron-produced precursor [11C]CO2. This paper presents an optimised alternative one-pot methodology of [11C]CO2 fixation-reduction for the rapid synthesis of [11C] PiB using an automated commercial platform and its quality control. RESULTS: [11C] PiB was obtained from a (25.9 ± 13.2)% (Average ± Variation Coefficient, n = 3) (end of synthesis, decay corrected) radiochemical yield from trapped [11C]CO2 after 1 min of labelling time using PhSiH3 / TBAF as the fixation-reduction system in Diglyme at 150 °C. The radiochemical purity was higher than 95% in all cases, and the molar activity was (61.4 ± 1.6) GBq/µmol. The radiochemical yield and activity (EOS) of formulated [11C] PiB from cyclotron-produced [11C]CO2 was (14.8 ± 12.1)%, decay corrected) and 9.88 GBq (± 6.0%), respectively. These are higher values compared to that of the 11C-methylation method with [11C]CH3OTf (~ 8.3%). CONCLUSIONS: The viability of the system PhSiH3 / TBAF to efficiently promote the radiosynthesis of [11C] PiB via direct [11C]CO2 fixation-reduction has been demonstrated. [11C] PiB was obtained through a fully automated radiosynthesis with a satisfactory yield, purity and molar activity. According to the results, the one-pot methodology employed could reliably yield sufficiently high tracer amounts for preclinical and clinical use.
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BACKGROUND: The SR101 N-(3-[18F]Fluoropropyl) sulfonamide ([18F]SRF101) is a Sulforhodamine 101 derivative that was previously synthesised by our group. The fluorescent dye SR101 has been reported as a marker of astroglia in the neocortex of rodents in vivo. OBJECTIVE: The aim of this study was to perform a toxicological evaluation of [18F]SRF101 and to estimate human radiation dosimetry based on preclinical studies. METHODS: Radiation dosimetry studies were conducted based on biokinetic data obtained from a mouse model. A single-dose toxicity study was carried out. The toxicological limit chosen was <100 µg, and allometric scaling with a safety factor of 100 for unlabelled SRF101 was selected. RESULTS: The absorbed and effective dose estimated using OLINDA/EXM V2.0 for male and female dosimetric models presented the same tendency. The highest total absorbed dose values were for different sections of the intestines. The mean effective dose was 4.03 x10-3 mSv/MBq and 5.08 x10-3 mSv/MBq for the male and female dosimetric models, respectively, using tissue-weighting factors from ICRP-89. The toxicity study detected no changes in the organ or whole-body weight, food consumption, haematologic or clinical chemistry parameters. Moreover, lesions or abnormalities were not found during the histopathological examination. CONCLUSION: The toxicological evaluation of SRF101 verified the biosafety of the radiotracer for human administration. The dosimetry calculations revealed that the radiation-associated risk of [18F]SRF101 would be of the same order as other 18F radiopharmaceuticals used in clinical applications. These study findings confirm that the novel radiotracer would be safe for use in human PET imaging.
Assuntos
Radioquímica/métodos , Compostos Radiofarmacêuticos/toxicidade , Rodaminas/toxicidade , Sulfonamidas/toxicidade , Animais , Feminino , Fluordesoxiglucose F18/química , Masculino , Camundongos , Doses de Radiação , Radiometria , Compostos Radiofarmacêuticos/síntese química , Rodaminas/química , Sulfonamidas/síntese químicaRESUMO
Cocaine exposure disrupts the maternal behavior of lactating rats, yet it is less known whether it alters the affective changes that accompany motherhood. As the long-term action of cocaine on anxiety varies according to the developmental stage of the individuals, this study aimed to compare the effect of a chronic treatment with cocaine to adult and adolescent non-pregnant females on their anxiety-like behavior and basal brain metabolic activity during lactation. Thus, adult and adolescent virgin rats were exposed to cocaine (0.0 or 15.0 mg/kg ip) during 10 days and were mated four days later. Anxiety behavior was evaluated on postpartum days 3-4 in the elevated plus maze test, and the basal brain glucose metabolism was determined on postpartum days 7-9 by means of [18F] fluorodeoxyglucose positron emission tomography. Cocaine treatment during adulthood increased the anxiety-like behavior of lactating females whereas its administration during adolescence decreased it. Also, the basal glucose metabolism of the medial prefrontal cortex differed between lactating females treated with cocaine during adulthood and adolescence. These differential effects of cocaine, according to the age at which the drug was administered, support the idea that the adolescent and adult brains have a distinct susceptibility to this drug, which leads to divergent long-term changes in the neural circuits that regulate anxiety during lactation.
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Fatores Etários , Ansiedade/metabolismo , Cocaína/farmacologia , Animais , Transtornos de Ansiedade/metabolismo , Encéfalo/metabolismo , Cocaína/metabolismo , Transtornos Relacionados ao Uso de Cocaína/metabolismo , Inibidores da Captação de Dopamina/farmacologia , Feminino , Glucose/metabolismo , Lactação/efeitos dos fármacos , Comportamento Materno/efeitos dos fármacos , Aprendizagem em Labirinto/efeitos dos fármacos , Período Pós-Parto/efeitos dos fármacos , Córtex Pré-Frontal/efeitos dos fármacos , Gravidez , RatosRESUMO
The aim of this study was quantitative comparison between 68Ga-Gallgas positron emission tomography (PET) and 99mTc-Technegas single photon emission computed tomography (SPECT) for lung ventilation function assessment in patients with moderate-to-severe obstructive pulmonary disease and to identify image-derived texture features correlating to the physiologic parameters. Five patients with moderate-to-severe chronic obstructive pulmonary disease with PET and SPECT lung ventilation scans were selected for this study. Threshold-based segmentations were used to compare ventilated regions between both imaging techniques. Histograms of both scans were compared to reveal main differences in distributions of radiotracers. Volumes of segmentation as well as 50 textural features measured in the pulmonary region were correlated to the forced expiratory volume in 1 s (FEV1) as the relevant physiological variable. A better peripheral distribution of the radiotracer was observed in PET scans for three out of five patients. A segmentation threshold of 27% and 31% for normalized scans, for PET and SPECT respectively, was found optimal for volume correlation with FEV1. A high correlation (Pearson correlation coefficient >0.9) was found between 16 texture features measured from SPECT and 7 features measured from PET and FEV1. Quantitative measurements revealed different tracer distribution in both techniques. These results suggest that tracer distribution patterns may depend on the cause of the pulmonary obstruction. We found several texture features measured from SPECT to correlate to FEV1.
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Neurodegenerative diseases have mainly been associated with neuronal death. Recent investigations have shown that astroglia may modulate neuroinflammation in the early and late stages of the disease. [11C]Deuterodeprenyl ([11C]DED) is a tracer that has been used for reactive astrocyte detection in Alzheimer's disease, Creutzfeldt-Jakob disease and amyotrophic lateral sclerosis, among others, with some limitations. To develop a new radiotracer for detecting astrocytosis and overcoming associated difficulties, we recently reported the synthesis of a sulfonamide derivative of Sulforhodamine 101 (SR101), labeled with 18F, namely SR101 N-(3-[18F]Fluoropropyl) sulfonamide ([18F]2B-SRF101). The red fluorescent dye SR101 has been used as a specific marker of astroglia in the neocortex of rodents using in vivo models. In the present work we performed a biological characterisation of the new tracer including biodistribution and micro-PET/computed tomography (CT) images. PET/CT studies with [11C]DED were also done to compare with [18F]2B-SRF101 in order to assess its potential as an astrocyte marker. Biodistribution studies with [18F]2B-SRF101 were carried out in C57BL6J black and transgenic (3xTg) mice. A hepatointestinal metabolization as well as the pharmacokinetic profile were determined, showing appropriate characteristics to become a PET diagnostic agent. Dynamic PET/CT studies were carried out with [18F]2B-SRF101 and [11C]DED to evaluate the distribution of both tracers in the brain. A significant difference in [18F]2B-SRF101 uptake was especially observed in the cortex and hippocampus, and it was higher in 3xTg mice than it was in the control group. These results suggested that [18F]2B-SRF101 is a promising candidate for more extensive evaluation as an astrocyte tracer. The difference observed for [18F]2B-SRF101 was not found in the case of [11C]DED. The comparative studies between [18F]2B-SRF101 and [11C]DED suggest that both tracers have different roles as astrocytosis markers in this animal model, and could provide different and complementary information at the same time. In this way, by means of a multitracer approach, useful information could be obtained for the staging of the disease.
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BACKGROUND: Alzheimer's disease (AD) is the most common form of dementia. Neuroimaging methods have widened the horizons for AD diagnosis and therapy. The goals of this work are the synthesis of 2-(3-fluoropropyl)-6-methoxynaphthalene (5) and its [18F]-radiolabeled counterpart ([18F]Amylovis), the in silico and in vitro comparative evaluations of [18F]Amylovis and [11C]Pittsburg compound B (PIB) and the in vivo preclinical evaluation of [18F]Amylovis in transgenic and wild mice. METHODS: Iron-catalysis cross coupling reaction, followed by fluorination and radiofluorination steps were carried out to obtain 5 and 18F-Amylovis. Protein/Aß plaques binding, biodistribution, PET/CT Imaging and immunohistochemical studies were conducted in healthy/transgenic mice. RESULTS: The synthesis of 5 was successful obtained. Comparative in silico studies predicting that 5 should have affinity to the Aß-peptide, mainly through π-π interactions. According to a dynamic simulation study the ligand-Aß peptide complexes are stable in simulation-time (ΔG = -5.31 kcal/mol). [18F]Amylovis was obtained with satisfactory yield, high radiochemical purity and specific activity. The [18F]Amylovis log Poct/PBS value suggests its potential ability for crossing the blood brain barrier (BBB). According to in vitro assays, [18F]Amylovis has an adequate stability in time. Higher affinity to Aß plaques were found for [18F]Amylovis (Kd 0.16 nmol/L) than PIB (Kd 8.86 nmol/L) in brain serial sections of 3xTg-AD mice. Biodistribution in healthy mice showed that [18F]Amylovis crosses the BBB with rapid uptake (7 %ID/g at 5 min) and good washout (0.11±0.03 %ID/g at 60 min). Comparative PET dynamic studies of [18F]Amylovis in healthy and transgenic APPSwe/PS1dE9 mice, revealed a significant high uptake in the mice model. CONCLUSION: The in silico, in vitro and in vivo results justify that [18F]Amylovis should be studied as a promissory PET imaging agent to detect the presence of Aß senile plaques.
Assuntos
Radioisótopos de Carbono/química , Radioisótopos de Flúor/química , Radioisótopos de Flúor/farmacologia , Naftalenos/química , Neuroimagem/métodos , Placa Amiloide/diagnóstico por imagem , Tomografia por Emissão de Pósitrons combinada à Tomografia Computadorizada , Radioquímica/métodos , Compostos Radiofarmacêuticos/síntese química , Compostos Radiofarmacêuticos/farmacologia , Animais , Simulação por Computador , Imuno-Histoquímica , Masculino , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Endogâmicos C57BL , Distribuição TecidualRESUMO
BACKGROUND: Overexpression of prostatic membrane antigen (PSMA) is associated with the progression and prognosis of prostate cancer. There are numerous studies using this peptide with the 68Ga radionuclide. Previous methods to synthetize 18F-labeled PSMA ligands with complexes [18F]AlF2+ have been achieved. However, these reported syntheses were performed manually, using small volumes. Therefore it is only possible to have the radiopharmaceutical on a small scale, for use in preclinical studies. 18F-labelled tracers allow higher doses increasing the number of examined patients. In addition, late images can be acquired in the case of uptake in lymph nodes, to discard inflammation. It is important to transfer the manual synthesis to an automatic module, producing a batch of the radiopharmaceutical with high activity in a safe and effective way. The aim of this work was to optimize the labeling of [18F]AlF-[GLU-UREA-LYS(AHX)-HBED-CC] in a Tracerlab FXFN® (GE) platform. RESULTS: The labeling up to the reactor corroborates the formation of the complex [18F]AlF-PSMA. After purification by HPLC, the radiopharmaceutical was achieved with a radiochemical purity higher than 90%. The quality control of the final product fulfilled all the requirements in agreement with USP, such as radiochemical purity (greater than 90%) and residual solvents. [18F]AlF-PSMA was obtained with a yield of 18 ± 3% (n = 7), not decay corrected (NCD) starting off from 500 to 2000 mCi the 18F and with a radiochemical purity of 95 ± 3% (n = 7). The product verified stability in the final formulation vial during 4 hs and in human plasma up to 1 h. CONCLUSION: The proposed method allowed the production of [18F]AlF-PSMA with suitable radiochemical purity in a commercial platform. High activities were achieved, with a simple and robust methodology appropriate for clinical purposes.
RESUMO
Positron emission tomography (PET) imaging of misfolded protein aggregates that form in neurodegenerative processes of the brain is key to providing a robust marker for improved diagnosis and evaluation of treatments. We report the development of advanced radiotracer candidates based on the sulfoxide scaffold found in proton pump inhibitors (lansoprazole, prevacid) with inherent affinity to neurofibrillary tangles in Alzheimer's disease and related disorders (e.g., dementia with Lewy bodies and the frontotemporal degeneration syndrome). First-in-man results obtained with [18F]lansoprazole and N-methyl-[18F]lansoprazole were used to guide the design of a set of 24 novel molecules with suitable properties for neuroimaging with PET. Compounds were synthesized and characterized pharmacologically, and the binding affinity of the compounds to synthetic human tau-441 fibrils was determined. Selectivity of binding was assessed using α-synuclein and ß-amyloid fibrils to address the key misfolded proteins of relevance in dementia. To complete the pharmacokinetic profiling in vitro, plasma protein binding and lipophilicity were investigated. Highly potent and selective new radiotracer candidates were identified for further study.
RESUMO
BACKGROUND: Glycine N-methyltransferase is an enzyme overexpressed in some neoplastic tissues. It catalyses the methylation of glycine using S-adenosyl methionine (SAM or AdoMet) as substrate. SAM is involved in a great variety of biochemical processes, including transmethylation reactions. Thus, [11C]SAM could be used to evaluate transmethylation activity in tumours. The only method reported for [11C]SAM synthesis is an enzymatic process with several limitations. We propose a new chemical method to obtain [11C]SAM, through a one-pot synthesis. METHOD: The optimization of [11C]SAM synthesis was carried out in the automated TRACERlab® FX C Pro module. Different labelling conditions were performed varying methylating agent, precursor amount, temperature and reaction time. The compound was purified using a semipreparative HPLC. Radiochemical stability, lipophilicity and plasma protein binding were evaluated. RESULTS: The optimum labelling conditions were [11C]CH3OTf as the methylating agent, 5 mg of precursor dissolved in formic acid at 60 °C for 1 minute. [11C]SAM was obtained as a diastereomeric mixture. Three batches were produced and quality control was performed according to specifications. [11C]SAM was stable in final formulation and in plasma. Log POCT obtained for [11C]SAM was (-2,01 ± 0,07) (n=4), and its value for plasma protein binding was low. CONCLUSION: A new chemical method to produce [11C]SAM was optimized. The radiotracer was obtained as a diastereomeric mixture with a 53:47 [(R,S)-isomer: (S,S)-isomer] ratio. The compound was within the quality control specifications. In vitro stability was verified. This compound is suitable to perform preclinical and clinical evaluations.