Micro-positron Emission Research Articles

Static magnetic field induces abnormality of glucose metabolism in rats’ brain and results in anxiety-like behavior

In this study, fifty-four male Wistar rats were randomly divided into four groups according to the static magnetic field (SMF) intensity, namely, control, low-intensity, moderate-intensity, and high-intensity groups. The rats' whole body was exposed to a superconducting magnet exposure source. The exposure SMF intensity for the low-intensity, moderate-intensity, and high-intensity groups was 50 m T, 100 m T, and 200 m T, respectively, and the exposure time was 1 h/day for consecutive 15 days. After different exposure times, glucose metabolism in rats' brain was evaluated by micro-positron emission tomography (micro-PET), and the expression of hexokinase 1(HK1) and 6-phosphate fructokinase-1(PFK1) was detected by western blot. The exploration and locomotion abilities of the rats were evaluated by conducting open field test (OFT). Furthermore, pathological changes of rats' brain were observed under a microscope by using hematoxylin–eosin staining. PET results showed that moderate-intensity SMFs could cause fluctuant changes in glucose metabolism in rats' brain and the abnormalities were SMF intensity dependent. The expression of the two rate-limiting enzymes HK1 and PFK1 in glucose metabolism in brain significantly decreased after SMF exposure. The OFT showed that the total distance, surrounding distance, activity time, and climbing and standing times significantly decreased after SMF exposure. The main pathological changes in the brain were pyknosis, edema of neurons, and slight widening of the perivascular space, which occurred after 15 times of exposure. This study indicated that SMF exposure could lead to abnormal glucose metabolism in the brain and might result in anxiety-like behaviors.

Synthesis and Evaluation of Fluorine-18 Labeled 2-Phenylquinoxaline Derivatives as Potential Tau Imaging Agents.

In this study, three pairs of optically pure 18F-labeled 2-phenylquinoxaline derivatives were evaluated as Tau imaging agents for the diagnosis of Alzheimer's disease (AD). The chiral 2-fluoromethyl-1,2-ethylenediol side chain was attached to the 2-phenylquinoxaline backbone to increase hydrophilicity, thereby improving the binding affinity of the probe to tangles and their selectivity toward Tau tangles over β-amyloid plaques (Aβ). These probes displayed excellent fluorescent properties and high selectivity for tangles on brain sections from transgenic mice (rTg4510) and AD patients. Quantitative binding assays with AD homogenates showed that the probes (R)-5 and (S)-16 have a high affinity (Ki = 4.1 and 10.3 nM, respectively) and high selectivity (30.5-fold and 34.6-fold, respectively) for tangles over Aβ. The high affinity and selectivity of (R)-[18F]5 and (S)-[18F]16 for tangles were further confirmed with autoradiography on AD brain tissue in vitro. In addition, they displayed sufficient blood-brain barrier penetration (7.06% and 10.95% ID/g, respectively) and suitable brain kinetics (brain2min/brain60min = 10.1, 6.5 respectively) in normal mice. Ex vivo metabolism studies and micro-positron emission computed tomography (PET) revealed high brain biostability, good brain kinetic properties, and low nonspecific binding for (S)-[18F]16. Together, these results demonstrate that (R)-[18F]5 and (S)-[18F]16 are promising PET probes for Tau tangles imaging.

Gastrodin - A potential drug used for the treatment of Tourette Syndrome

Gastrodin (Gas) represents the major active component of Gastrodia elata, a Chinese herb. Clinically, Gas is widely used for its sedative, anticonvulsive and neuroprotective properties. This work aimed to assess Gas for its efficacy in Tourette Syndrome (TS) treatment. Twenty-four rats were randomized to the blank control (n = 6) and experimental (n = 18) groups. The experimental group was administered continuous injection of 3, 3′-iminodipropionitrile (IDPN) intraperitoneally for 7 days, and subdivided into the IDPN + NS, IDPN + Hal, and IDPN + Gas groups (n = 6). The control and IDPN + NS groups received saline intragastrically, while the IDPN + Hal and IDPN + Gas groups were administered Gas and Haloperidol, respectively, for 8 weeks. Then, micro-positron emission tomography (PET) was performed for measuring the density and brain distribution of dopamine D2 receptors (D2Rs), dopamine transporters (DATs), 5-HT2A receptors (5-HT2ARs) and 5-HT transporters (SERTs). According to stereotypical behavior experiments, IDPN significantly induced abnormal stereotypical behaviors in rats in comparison with control animals. In addition, micro-PET revealed that by reducing the amounts of D2Rs and increasing those of DATs, Gas could significantly reduce stereotypical TS-like behaviors in this rat model system. Furthermore, Gas treatment reduced the density of SERTs, which could indirectly decrease DA release. The current study demonstrated that Gas could be effective in treating TS.

Pre- and early postnatal enriched environmental experiences prevent neonatal hypoxia-ischemia late neurodegeneration via metabolic and neuroplastic mechanisms.

Prenatal and early postnatal periods are important for brain development and neural function. Neonatal insults such as hypoxia-ischemia (HI) causes prolonged neural and metabolic dysregulation, affecting central nervous system maturation. There is evidence that brain hypometabolism could increase the risk of adult-onset neurodegenerative diseases. However, the impact of non-pharmacologic strategies to attenuate HI-induced brain glucose dysfunction is still underexplored. This study investigated the long-term effects of early environmental enrichment in metabolic, cell, and functional responses after neonatal HI. Thereby, male Wistar rats were divided according to surgical procedure, sham, and HI (performed at postnatal day 3), and the allocation to standard (SC) or enriched condition (EC) during gestation and lactation periods. In-vivo cerebral metabolism was assessed by means of [18 F]-FDG micro-positron emission tomography, and cognitive, biochemical, and histological analyses were performed in adulthood. Our findings reveal that HI causes a reduction in glucose metabolism and glucose transporter levels as well as hyposynchronicity in metabolic brain networks. However, EC during prenatal or early postnatal period attenuated these metabolic disturbances. A positive correlation was observed between [18 F]-FDG values and volume ratios in adulthood, indicating that preserved tissue by EC is metabolically active. EC promotes better cognitive scores, as well as down-regulation of amyloid precursor protein in the parietal cortex and hippocampus of HI animals. Furthermore, growth-associated protein 43 was up-regulated in the cortex of EC animals. Altogether, results presented support that EC during gestation and lactation period can reduce HI-induced impairments that may contribute to functional decline and progressive late neurodegeneration.

A novel PET tracer 18F-deoxy-thiamine: synthesis, metabolic kinetics, and evaluation on cerebral thiamine metabolism status

BackgroundSome neuropsychological diseases are associated with abnormal thiamine metabolism, including Korsakoff–Wernicke syndrome and Alzheimer’s disease. However, in vivo detection of the status of brain thiamine metabolism is still unavailable and needs to be developed.MethodsA novel PET tracer of 18F-deoxy-thiamine was synthesized using an automated module via a two-step route. The main quality control parameters, such as specific activity and radiochemical purity, were evaluated by high-performance liquid chromatography (HPLC). Radiochemical concentration was determined by radioactivity calibrator. Metabolic kinetics and the level of 18F-deoxy-thiamine in brains of mice and marmosets were studied by micro-positron emission tomography/computed tomography (PET/CT). In vivo stability, renal excretion rate, and biodistribution of 18F-deoxy-thiamine in the mice were assayed using HPLC and γ-counter, respectively. Also, the correlation between the retention of cerebral 18F-deoxy-thiamine in 60 min after injection as represented by the area under the curve (AUC) and blood thiamine levels was investigated.ResultsThe 18F-deoxy-thiamine was stable both in vitro and in vivo. The uptake and clearance of 18F-deoxy-thiamine were quick in the mice. It reached the max standard uptake value (SUVmax) of 4.61 ± 0.53 in the liver within 1 min, 18.67 ± 7.04 in the kidney within half a minute. The SUV dropped to 0.72 ± 0.05 and 0.77 ± 0.35 after 60 min of injection in the liver and kidney, respectively. After injection, kidney, liver, and pancreas exhibited high accumulation level of 18F-deoxy-thiamine, while brain, muscle, fat, and gonad showed low accumulation concentration, consistent with previous reports on thiamine distribution in mice. Within 90 min after injection, the level of 18F-deoxy-thiamine in the brain of C57BL/6 mice with thiamine deficiency (TD) was 1.9 times higher than that in control mice, and was 3.1 times higher in ICR mice with TD than that in control mice. The AUC of the tracer in the brain of marmosets within 60 min was 29.33 ± 5.15 and negatively correlated with blood thiamine diphosphate levels (r = − 0.985, p = 0.015).ConclusionThe 18F-deoxy-thiamine meets the requirements for ideal PET tracer for in vivo detecting the status of cerebral thiamine metabolism.

Relationship between the invasion of lymphocytes and cytokines in the tumor microenvironment and the interval after single brachytherapy hypofractionated radiotherapy and conventional fractionation radiotherapy in non-small cell lung Cancer

BackgroundThe effect of brachytherapy on lymphocytes and cytokines in the tumor microenvironment is unclear. This study aimed to analyze the relationship between the invasion of lymphocytes and cytokines in the tumor microenvironment and the interval after single brachytherapy hypofractionated radiotherapy (SBHFRT) and conventional fractionation radiotherapy (CFRT) in non-small cell lung cancer (NSCLC).MethodsLewis tumor-bearing mice were randomly divided into control, CFRT, and SBHFRT groups. On days 7 and 14 after radiation, the expression levels of CD86+, CD4+, CD8+, and Foxp3+ cells, and levels of Ki-67+ protein were detected by immunohistochemistry, and the tumor necrosis rate was calculated. Following this, the levels of interleukin-10 (IL-10), IL-12, and interferon-γ (IFN-γ) were detected by enzyme-linked immunosorbent assay. The apoptosis rate was evaluated via flow cytometry. The tumor volume and tumor growth inhibition rate (TGIR) were calculated on day 14. Tumor metabolism was assessed via 18F-FDG micropositron emission tomography/computer tomography.ResultsThe tumor volume reduced by 22.0% and TGIR increased by 92.2% (p < 0.05) in the SBHFRT group. Further, on days 7 and 14 after radiation, tumor metabolism, Ki-67+ and Foxp3+ expression levels, and IL-10 levels were lower, and tumor necrosis and apoptosis rates; CD86+, CD4+, and CD8+ expression levels; and IL-12 and IFN-γ levels were higher in the SBHFRT group than in the CFRT group, particularly on day 7.ConclusionSBHFRT could lead to more accumulation of dendritic cells, anti-tumor lymphocytes, and cytokines, and further reduce the aggregation of immunosuppressive lymphocytes and cytokines in the tumor microenvironment compared with CFRT, and the difference was the most obvious on day 7 after radiation. The clinical significance of the findings remains to be further verified.

Feasibility study of 68Ga-labeled CART cells for in vivo tracking using micro-positron emission tomography imaging.

Clinical tracking of chimeric antigen receptor (CAR) T cells in vivo by positron emission tomography (PET) imaging is an area of intense interest. But the long-livedpositron emitter-labeled CAR T cells stay in the liver and spleen for days or even weeks. Thus, the excessive absorbed effective dose becomes a major biosafety issue leading it difficult for clinical translation. In this study we used68Ga, a commercially available short-livedpositron emitter, to label CAR T cells for noninvasive cell tracking in vivo. CAR T cells could be tracked in vivo by 68Ga-PET imaging for at least 6 h. We showed a significant correlation between the distribution of 89Zr and 68Ga-labeled CAR T cells in the same tissues (lungs, liver, and spleen). The distribution and homing behavior of CAR T cells at the early period is highly correlated with the long-term fate of CAR T cells in vivo. And the effective absorbed dose of 68Ga-labeled CAR T cells is only one twenty-fourth of 89Zr-labeled CAR T cells, which was safe for clinical translation. We conclude the feasibility of 68Ga instead of 89Zr directly labeling CAR T cells for noninvasive tracking of the cells in vivo at an early stage based on PET imaging. This method provides a potential solution to the emerging need for safe and practical PET tracer for cell tracking clinically.

Positron emission tomography imaging of a novel Anxa1-targeted peptide 18 F-Al-NODA-Bn-p-SCN-GGGRDN-IF7 in A431 cancer mouse models.

Annexin 1 (Anxa1) is a highly specific surface marker of tumor vasculature in the lung and prostate solid tumors. The IF7 peptide was modified with a hydrophilic linker, GGGRDN, and coupled with a new bifunctional chelating agent NODA-Bn-p-SCN. The resulting peptides (NODA-Bn-p-SCN-GGGRDN-IF7) were successfully labeled with Al18 F. The targeting characteristics of the radiolabeled peptides were evaluated in the Anxa1 positive A431 tumor model. Micro-positron emission tomography (micro-PET) imaging revealed that the A431 tumors were clearly visualized (5.74 ± 1.13%ID/g, 3.92 ± 0.78%ID/g and 1.30 ± 0.43%ID/g at 0.5, 1, and 2 h post-injection, respectively). Anxa1 binding specificity was also demonstrated by reduced tumor uptake after co-injection with excessive unlabeled GGGRDN-IF7 peptide at 30, 60, and 120 min post-injection. 18 F-Al-NODA-Bn-p-SCN-GGGRDN-IF7 might be a potential PET imaging agent for detecting Anxa1 levels in cancers due to the favorable characteristics such as convenient synthesis, specific Anxa1 targeting, and good tumor uptakes.

Visualization of translocator protein (18kDa) (TSPO) in the retina of diabetic retinopathy rats using fluorine-18-DPA-714.

To investigate the feasibility of a noninvasive method for imaging translocator protein (18kDa) (TSPO) in the retina of diabetic retinopathy (DR) rats using fluorine-18-DPA-714 ([18F]-DPA-714) micro-positron emission tomography (PET)/X-ray computed tomography (CT). Sprague-Dawley (SD) rats were intraperitoneally injected with streptozocin (STZ) (65mgkg-1, ip) to induce diabetes mellitus (DM). The TSPO in both eyes was detected by PET/CT using [18F]-DPA-714 12weeks after the establishment of the DM model. The mean standardized uptake value (SUVmean) was analyzed. Western blot and quantitative real-time polymerase chain reaction (PCR) were performed to detect the TSPO protein and mRNA levels in the retina. PET/CT results showed that the SUV of [18F]-DPA-714 was markedly reduced in the retina of DR rats compared with that of normal controls 12weeks after diabetes induction. The SUVmean of regions of interest (ROIs) in the retinas of DR and normal control rats was 0.883 ± 0.078 and 2.525 ± 0.213 (P < 0.001), respectively. The results of PET/CT were in line with the Western blots and quantitative real-time PCR. The PET results demonstrated that TSPO was decreased in the early stage of DR. [18F]-DPA-714 PET/CT appears to be a useful noninvasive imaging method for detecting TSPO in the retina. A decrease in the TSPO level in the retina may play an important role in the development of DR.

Hybrid Imaging Agents for Pretargeting Applications Based on Fusarinine C-Proof of Concept.

Hybrid imaging combining the beneficial properties of radioactivity and optical imaging within one imaging probe has gained increasing interest in radiopharmaceutical research. In this study, we modified the macrocyclic gallium-68 chelator fusarinine C (FSC) by conjugating a fluorescent moiety and tetrazine (Tz) moieties. The resulting hybrid imaging agents were used for pretargeting applications utilizing click reactions with a trans-cyclooctene (TCO) tagged targeting vector for a proof of principle both in vitro and in vivo. Starting from FSC, the fluorophores Sulfocyanine-5, Sulfocyanine-7, or IRDye800CW were conjugated, followed by introduction of one or two Tz motifs, resulting in mono and dimeric Tz conjugates. Evaluation included fluorescence microscopy, binding studies, logD, protein binding, in vivo biodistribution, µPET (micro-positron emission tomography), and optical imaging (OI) studies. 68Ga-labeled conjugates showed suitable hydrophilicity, high stability, and specific targeting properties towards Rituximab-TCO pre-treated CD20 expressing Raji cells. Biodistribution studies showed fast clearance and low accumulation in non-targeted organs for both SulfoCy5- and IRDye800CW-conjugates. In an alendronate-TCO based bone targeting model the dimeric IRDye800CW-conjugate resulted in specific targeting using PET and OI, superior to the monomer. This proof of concept study showed that the preparation of FSC-Tz hybrid imaging agents for pretargeting applications is feasible, making such compounds suitable for hybrid imaging applications.

Explicit tracking of CO2-flow at the core scale using micro-Positron Emission Tomography (μPET)

Safe subsurface sequestration of carbon dioxide (CO2) is becoming increasingly important to meet climate goals and curb atmospheric CO2 concentrations. The world-wide CO2 storage capacity in carbonate formations is significant; within deep, saline aquifers and through several CO2-enhanced oil recovery projects, with associated CO2 storage. Carbonates are complex, both in terms of heterogeneity and reactivity, and improved core scale and sub core-scale analysis of CO2 flow phenomena is necessary input to simulators, aiming to establish large-scale behavior. This paper presents a recent advancement in in-situ imaging of CO2 flow, utilizing high-resolution micro-Positron Emission Tomography and radioactive tracer [11C]arbon dioxide to explicitly track CO2 during dynamic flow and subsequent trapping at the core scale. Unsteady state water injection (imbibition) and CO2 injection (drainage) were performed in a low-permeable chalk core at elevated pressure conditions. Short-lived radioisotopes were used to label water and CO2, respectively, and facilitated explicit tracking of each phase separately during single phase injection. Local flow patterns and dynamic spatial fluid saturations were determined from in-situ imaging during each experimental step. Initial miscible displacement revealed displacement heterogeneities in the chalk core, and dynamic image data was used to disclose and quantify local permeability variations. Radial permeability variations influenced subsequent flow patterns, where CO2 predominantly flooded the higher-permeability outer part of the core, leaving a higher water saturation in the inner core volume. Injection of water after CO2 flooding is proposed to be the most rapid and effective way to ensure safe storage, by promoting capillary trapping of CO2. PET imaging showed that presence of CO2 reduced the flow of water in higher-permeability areas, improving sweep efficiency and promoting a nearly ideal core-scale displacement. Alternate injections of water and gas is also expected to improve sweep efficiency and contribute to improved oil recovery and CO2 storage on larger scales. Sub-core analysis showed that residually trapped CO2 was evenly distributed in the chalk core, occupying 40% of the pore volume after ended water injection. Micro-Positron Emission Tomography yielded excellent small-scale resolution of both water and CO2 flow, and may contribute to unlocking fluid flow dynamics and determining mechanisms on the millimeter scale; presenting a unique opportunity in experimental core-scale evaluations of CO2 storage and security.

Benefit of Later-Time-Point PET Imaging of HER3 Expression Using Optimized Radiocobalt-Labeled Affibody Molecules.

HER3-binding affibody molecules are a promising format for visualization of HER3 expression. Cobalt-55, a positron-emitting isotope, with a half-life of 17.5 h, allows for next-day imaging. We investigated the influence of the charge of the radiocobalt–chelator complex on the biodistribution of anti-HER3 affibody molecule (HE)3-ZHER3 and compared the best radiocobalt-labeled variant with a recently optimized gallium-labeled variant. Affibody conjugates (HE)3-ZHER3-X (X = NOTA, NODAGA, DOTA, DOTAGA) were labeled with [57Co]Co (surrogate for 55Co). Affinity measurements, binding specificity and cellular processing were studied in two HER3-expressing cancer cell lines. Biodistribution was studied 3 and 24 h post-injection (pi) in mice with HER3-expressing BxPC-3 xenografts and compared to [68Ga]Ga-(HE)3-ZHER3-NODAGA. Micro-single-photon emission tomography/computed tomography (microSPECT/CT) and micro-positron emission tomography/computed tomography (microPET/CT) imaging was performed 3 and 24 h pi. Stably labeled conjugates bound to HER3 with subnanomolar affinity. [57Co]Co-(HE)3-ZHER3-DOTA had the best tumor retention and a significantly lower concentration in blood than other conjugates, leading to superior tumor-to-blood and tumor-to-liver ratios 24 h pi. Compared to [68Ga]Ga-(HE)3-ZHER3-NODAGA 3 h pi, [57Co]Co-(HE)3-ZHER3-DOTA provided superior imaging contrast in liver 24 h pi. Concluding, the composition and charge of the [57Co]Co–chelator complex influenced the uptake in tumors and normal tissue. [57Co]Co-(HE)3-ZHER3-DOTA provided the best imaging properties among the cobalt-labeled conjugates. Delayed imaging of HER3 expression with [57Co]Co-(HE)3-ZHER3-DOTA improved imaging contrast compared to early-time-point imaging with [68Ga]Ga-(HE)3-ZHER3-NODAGA.

World Trade Center-Cardiorespiratory and Vascular Dysfunction: Assessing the Phenotype and Metabolome of a Murine Particulate Matter Exposure Model

Vascular changes occur early in the development of obstructive airways disease. However, the vascular remodeling and dysfunction due to World Trade Center-Particulate Matter (WTC-PM) exposure are not well described and are therefore the focus of this investigation. C57Bl/6 female mice oropharyngeally aspirated 200 µg of WTC-PM53 or phosphate-buffered saline (PBS) (controls). 24-hours (24-hrs) and 1-Month (1-M) after exposure, echocardiography, micro-positron emission tomography(µ-PET), collagen quantification, lung metabolomics, assessment of antioxidant potential and soluble-receptor for advanced glycation end products (sRAGE) in bronchoalveolar lavage(BAL) and plasma were performed. 24-hrs post-exposure, there was a significant reduction in (1) Pulmonary artery(PA) flow-velocity and pulmonary ejection time(PET) (2) Pulmonary acceleration time(PAT) and PAT/PET, while (3) Aortic ejection time(AET) and velocity time integral(VTI) were increased, and (4) Aortic acceleration time (AAT)/AET, cardiac output and stroke volume were decreased compared to controls. 1-M post-exposure, there was also significant reduction of right ventricular diameter as right ventricle free wall thickness was increased and an increase in tricuspid E, A peaks and an elevated E/A. The pulmonary and cardiac standard uptake value and volume 1-M post-exposure was significantly elevated after PM-exposure. Similarly, α-smooth muscle actin(α-SMA) expression, aortic collagen deposition was elevated 1-M after PM exposure. In assessment of the metabolome, prominent subpathways included advanced glycation end products (AGEs), phosphatidylcholines, sphingolipids, saturated/unsaturated fatty acids, eicosanoids, and phospholipids. BAL superoxide dismutase(SOD), plasma total-antioxidant capacity activity, and sRAGE (BAL and plasma) were elevated after 24-hrs. PM exposure and associated vascular disease are a global health burden. Our study shows persistent WTC-Cardiorespiratory and Vascular Dysfunction (WTC-CaRVD), inflammatory changes and attenuation of antioxidant potential after PM exposure. Early detection of vascular disease is crucial to preventing cardiovascular deaths and future work will focus on further identification of bioactive therapeutic targets.

Evaluation of Pan-SSTRs Targeted Radioligand [64Cu]NOTA-PA1 Using Micro-PET Imaging in Xenografted Mice

64Cu-labeled new pan-somatostatin receptors (pan-SSTRs) probe PA1 was synthesized, characterized, and evaluated by in vitro and in vivo experiments. [64Cu]NOTA-PA1 was obtained with high specific activity, high radiochemical purity, and good stability. Cell uptake of [64Cu]NOTA-PA1 was higher than that of [64Cu]DOTA-TATE in MCF-7, A549, BGC823, and HT-29 cell lines. [64Cu]NOTA-PA1 showed high binding affinity for SSTRs expressed in A549 cells. The in vivo biodistribution and micropositron emission tomography (micro-PET) imaging studies of [64Cu]NOTA-PA1 revealed good detection ability in MCF-7 and A549 xenografted nude mice. The radiosynthesis, quality control, and preliminary biological evaluation of [64Cu]NOTA-PA1 have broaden the application of radiolabeled octreotide for SSTRs imaging, which could act as a potential multisubtypes targeted radiotracer for imaging SSTRs-positive tumors.

Deep Brain Stimulation of the Medial Forebrain Bundle in a Rodent Model of Depression: Exploring Dopaminergic Mechanisms with Raclopride and Micro-PET

Background: Deep brain stimulation (DBS) of the medial forebrain bundle (MFB) can reverse depressive-like symptoms clinically and in experimental models of depression, but the mechanisms of action are unknown. Objectives: This study investigated the role of dopaminergic mechanisms in MFB stimulation-mediated behavior changes, in conjunction with raclopride administration and micropositron emission tomography (micro-PET). Methods: Flinders Sensitive Line (FSL) rats were allocated into 4 groups: FSL (no treatment), FSL+ (DBS), FSL.R (FSL with raclopride), and FSL.R+ (FSL with raclopride and DBS). Animals were implanted with bilateral electrodes targeting the MFB and given 11 days access to raclopride in the drinking water with or without concurrent continuous bilateral DBS over the last 10 days. Behavioral testing was conducted after stimulation. A PET scan using [¹⁸F]desmethoxyfallypride was performed to determine D2 receptor availability before and after raclopride treatment. Changes in gene expression in the nucleus accumbens and the hippocampus were assessed using quantitative polymerase chain reaction. Results: Micro-PET imaging showed that raclopride administration blocked 36% of the D2 receptor in the striatum, but the relative level of blockade was reduced/modulated by stimulation. Raclopride treatment enhanced depressive-like symptoms in several tasks, and the MFB DBS partially reversed the depressive-like phenotype. The raclopride-treated MFB DBS animals had increased levels of mRNA coding for dopamine receptor D1 and D2 suggestive of a stimulation-mediated increase in dopamine receptors. Conclusion: Data suggest that chronic and continuous MFB DBS could act via the modulation of the midbrain dopaminergic transmission, including impacting on the postsynaptic dopamine receptor profile.

Ketamine inhibits aerobic glycolysis in colorectal cancer cells by blocking the NMDA receptor‐CaMK II‐c‐Myc pathway

Aerobic glycolysis plays a crucial role in cancer progression. Ketamine is often used for cancer pain relief in clinical settings. Moreover, ketamine inhibits proliferation and induces apoptosis in many cancer cell types. However, the anti-tumour mechanism of ketamine is still poorly understood. In the present study, we survey whether and how ketamine inhibits aerobic glycolysis in colon cancer cells. Glycolysis of colon cancer cells was determined by detecting the extracellular acidification rate in HT29 and SW480 cells. Quantitative real-time PCR was employed to determine mRNA expression. Calcium levels were detected with a Fluo-3 AM fluorescence kit. Micro-positron emission tomography/computed tomography (microPET/CT) imaging was employed to assess glycolysis in the tumours of the xenograft model. Ketamine treatment inhibited colon cancer cell viability and migration in HT29 and SW480 cells. Moreover, ketamine decreased aerobic glycolysis and decreased the expression of glycolysis-related proteins in HT29 and SW480 cells. MicroPET/CT demonstrated that ketamine decreased 18F-FDG uptake in the xenograft model. In addition, ketamine inhibited c-Myc expression and CaMK II phosphorylation and decreased calcium levels. Further, dizocilpine (an NMDAR inhibitor), and KN93 (a CaMK II inhibitor), decreased CaMK II phosphorylation, c-Myc expression, and cancer cell glycolysis; these results were similar to those with ketamine treatment. Furthermore, the anti-tumour effect of ketamine was counteracted by rapastinel (an NMDAR activator). Ketamine inhibited aerobic glycolysis in colon cancer cells probably by blocking the NMDA receptor-CaMK II-c-Myc pathway, thus attenuating colon cancer cell viability and migration.

Electroacupuncture attenuates cognition impairment via anti-neuroinflammation in an Alzheimer\u2019s disease animal model

BackgroundAlzheimer’s disease (AD) is a neurodegenerative disorder characterized by progressive loss of cognitive abilities and memory leading to dementia. Electroacupuncture (EA) is a complementary alternative medicine approach, applying an electrical current to acupuncture points. In clinical and animal studies, EA causes cognitive improvements in AD and vascular dementia. However, EA-induced changes in cognition and microglia-mediated amyloid β (Aβ) degradation have not been determined yet in AD animals. Therefore, this study investigated the EA-induced molecular mechanisms causing cognitive improvement and anti-inflammatory activity in five familial mutation (5XFAD) mice, an animal model of AD.Methods5XFAD mice were bilaterally treated with EA at the Taegye (KI3) acupoints three times per week for 2 weeks. To evaluate the effects of EA treatment on cognitive functions, novel object recognition and Y-maze tests were performed with non-Tg, 5XFAD (Tg), and EA-treated 5XFAD (Tg + KI3) mice. To examine the molecular mechanisms underlying EA effects, western blots, immunohistochemistry, and micro-positron emission tomography scans were performed. Furthermore, we studied synapse ultrastructures with transmission electron microscopy and used electrophysiology to investigate EA effects on synaptic plasticity in 5XFAD mice.ResultsEA treatment significantly improved working memory and synaptic plasticity, alleviated neuroinflammation, and reduced ultrastructural degradation of synapses via upregulation of synaptophysin and postsynaptic density-95 protein in 5XFAD mice. Furthermore, microglia-mediated Aβ deposition was reduced after EA treatment and coincided with a reduction in amyloid precursor protein.ConclusionsOur findings demonstrate that EA treatment ameliorates cognitive impairment via inhibition of synaptic degeneration and neuroinflammation in a mouse model of AD.

Development and Characterization of a Genetic Mouse Model of KRAS Mutated Colorectal Cancer.

Patients with KRAS mutated colorectal cancer (CRC) represent a cohort with unmet medical needs, with limited options of FDA-approved therapies. Representing 40–45% of all CRC patients, they are considered ineligible to receive anti-EGFR monoclonal antibodies that have added a significant therapeutic benefit for KRAS wild type CRC patients. Although several mouse models of CRC have been developed during the past decade, one genetically resembling the KRAS mutated CRC is yet to be established. In this study C57 BL/6 mice with truncated adenomatous polyposis coli (APC) floxed allele was crossed with heterozygous KRAS floxed outbred mice to generate an APCf/f KRAS+/f mouse colony. In another set of breeding, APC floxed mice were crossed with CDX2-Cre-ERT2 mice and selected for APCf/f CDX2-Cre-ERT2 after the second round of inbreeding. The final model of the disease was generated by the cross of the two parental colonies and viable APC f/f KRAS +/f CDX2-Cre-ERT2 (KPC: APC) were genotyped and characterized. The model animals were tamoxifen (TAM) induced to generate tumors. Micro-positron emission tomography (PET) scan was used to detect and measure tumor volume and standard uptake value (SUV). Hematoxylin and eosin (H&E) staining was performed to establish neoplasm and immunohistochemistry (IHC) was performed to determine histological similarities with human FFPE biopsies. The MSI/microsatellite stable (MSS) status was determined. Finally, the tumors were extensively characterized at the molecular level to establish similarities with human CRC tumors. The model KPC: APC animals are conditional mutants that developed colonic tumors upon induction with tamoxifen in a dose-dependent manner. The tumors were confirmed to be malignant within four weeks of induction by H&E staining and higher radioactive [18F] fluoro-2-deoxyglucose (FDG) uptake (SUV) in micro-PET scan. Furthermore, the tumors histologically and molecularly resembled human colorectal carcinoma. Post tumor generation, the KPC: APC animals died of cachexia and rectal bleeding. Implications: This model is an excellent preclinical platform to molecularly characterize the KRAS mutated colorectal tumors and discern appropriate therapeutic strategies to improve disease management and overall survival.

Micro-PET Imaging Demonstrates 3-O-β-D-Glucopyranosyl Platycodigenin as an Effective Metabolite Affects Permeability of Cell Membrane and Improves Dosimetry of [18F]-Phillygenin in Lung Tissue.

Platycodon grandiflorum, as a traditional medicinal plant, is commonly used in the treatment of pulmonary disease. Platycodon saponins are proposed as active ingredients. However, the role of secondary saponin metabolites (SSM) in the traditional use of Platycodon has not yet been fully clarified. In this study, [18F]-phillygenin ([18F]-PH) probe was synthesized and thereby used as a tracer for micro-positron emission tomography scanning to explore the effects of platycodon saponins. The membrane permeability with different SSM was evaluated in vitro based on the dye-carrying capacity of fluorescein isothiocyanate. The results showed that total platycodon saponins improved the dosimetry of [18F]-PH in the lung tissue, and an SSM named 3-O-β-D-glucopyranosyl platycodigenin (GPD682) appreciably changed the distribution of drugs both in vitro and in vivo. We propose that GPD682 could be utilized as an important ingredient to help drug delivery to the lung tissue and improve the treatment of respiratory disease.

The TGF-β/Smad Pathway Inhibitor SB431542 Enhances The Antitumor Effect Of Radiofrequency Ablation On Bladder Cancer Cells.

BackgroundDespite progress achieved in bladder cancer (BC) treatment, the prognosis of patients with advanced BC (ie, metastasized from the bladder to other organs) is poor. Although mortality in cases of low-grade BC is rare, the treatment, such as a radical cystectomy, often has a serious impact on the quality of life. Thus, research is needed to identify more effective treatment strategies and this work is aiming to examine the potential application of combination of radiofrequency ablation (RFA) and SB435142, a inhibitor of transforming growth factor β (TGFβ)/Smad pathway.MethodsBC cells were transplanted into nude mice (thymusdeficiency Bal B/c) to form subcutaneous tumors. The mice with subcutaneous tumors were then treated with RFA and oral administration of SB431542, an inhibitor of TGFβ/Smad signaling pathway. The antitumor effect of RFA was measured by tumor proliferation curves and micro-positron emission computed tomography (micro-PET). The effect of SB431542 on epithelial–mesenchymal transition (EMT) related regulators in subcutaneous tumor tissues formed by BC cells were examined by quantitative real-time polymerase chain reaction (qPCR) experiments.ResultsThe SB431542 treatment enhanced the antitumor effect of RFA on subcutaneous growth of BCs. SB431542 also decreased EMT-related regulators in subcutaneous tumor tissues formed by BC cells in nude mice.ConclusionSB431542 enhances the effect of RFA on BC.