Real-Time Molecular Imaging of Tricarboxylic Acid Cycle Metabolism in Vivo by Hyperpolarized 1-^(13)C Diethyl Succinate

The Krebs tricarboxylic acid cycle (TCA) is central to metabolic energy production and is known to be altered in many disease states. Real-time molecular imaging of the TCA cycle in vivo will be important in understanding the metabolic basis of several diseases. Positron emission tomography (PET) with FDG-glucose (2-[^(18)F]fluoro-2-deoxy-d-glucose) is already being used as a metabolic imaging agent in clinics. However, FDG-glucose does not reveal anything past glucose uptake and phosphorylation. We have developed a new metabolic imaging agent, hyperpolarized diethyl succinate-1-^(13)C-2,3-d_2 , that allows for real-time in vivo imaging and spectroscopy of the TCA cycle. Diethyl succinate can be hyperpolarized via parahydrogen-induced polarization (PHIP) in an aqueous solution with signal enhancement of 5000 compared to Boltzmann polarization. ^(13)C magnetic resonance spectroscopy (MRS) and magnetic resonance imaging (MRI) were achieved in vivo seconds after injection of 10–20 μmol of hyperpolarized diethyl succinate into normal mice. The downstream metabolites of hyperpolarized diethyl succinate were identified in vivo as malate, succinate, fumarate, and aspartate. The metabolism of diethyl succinate was altered after exposing the animal to 3-nitropropionate, a known irreversible inhibitor of succinate dehydrogenase. On the basis of our results, hyperpolarized diethyl succinate allows for real-time in vivo MRI and MRS with a high signal-to-noise ratio and with visualization of multiple steps of the TCA cycle. Hyperpolarization of diethyl succinate and its in vivo applications may reveal an entirely new regime wherein the local status of TCA cycle metabolism is interrogated on the time scale of seconds to minutes with unprecedented chemical specificity and MR sensitivity

Rapid Evaluation of Mutant Exon-11 in c-kit in a Recurrent MCT Case Using CD117 Immunocytofluorescence, FACS-Cell Sorting, and PCR

A 13-year-old, poodle-mixed, male dog was referred to the oncology unit in our faculty's small animal teaching hospital with the problem of rapid recurrent MCT. The owner and the veterinarian would like to use a tyrosine kinase inhibitor (TKI) for the dog. Therefore, fine-needle aspiration (FNA) was performed to collect the MCT cells and these cells were submitted to our laboratory for the detection of internal-tandem-duplicated (ITD) mutation of exon-11 in c-kit, prior to the treatment. The aim of this paper is to demonstrate the use of combinatorial protocol for the rapid evaluation of ITD mutation in MCT cells harvested by FNA. However, there was no ITD-mutant exon-11 that had been observed in this case

IS-16 Innovation on Microfluidics-based Device for Single Cell Analysis, A Canine Cutaneous Mast Cell Tumor Model

Recently, our laboratory, Companion Animal Cancer Research Unit, CAC-RU is interested in cancer stem cell (CSC) analysis both at the single cell and the tissue-based levels. However, cellular heterogeneity is still the major hassle for our comprehension in CSC biology. Therefore, to overcome and eradicate this big obstacles, a single cell analysis method must be established. Our laboratory has finally setup and integrated the microfluidics-based single cell analysis into our CSC researches under the association with Department of Mechanical Engineering, Faculty of Engineering, Chulalongkorn University and Thai Micro-electronic Centre, NECTEC, Ministry of Science and Technology, Thailand and Faculty of Medical Technic, Mahidol University since 2013 till present

Change in Brain Magnetic Resonance Spectroscopy after Treatment during Acute HIV Infection

Objective: Single voxel proton magnetic resonance spectroscopy (MRS) can be used to monitor changes in brain inflammation and neuronal integrity associated with HIV infection and its treatments. We used MRS to measure brain changes during the first weeks following HIV infection and in response to antiretroviral therapy (ART). Methods: Brain metabolite levels of N-acetyl aspartate (NAA), choline (tCHO), creatine (CR), myoinositol (MI), and glutamate and glutamine (GLX) were measured in acute HIV subjects (n = 31) and compared to chronic HIV+individuals (n = 26) and HIV negative control subjects (n = 10) from Bangkok, Thailand. Metabolites were measured in frontal gray matter (FGM), frontal white matter (FWM), occipital gray matter (OGM), and basal ganglia (BG). Repeat measures were obtained in 17 acute subjects 1, 3 and 6 months following initiation of ART. Results: After adjustment for age we identified elevated BG tCHO/CR in acute HIV cases at baseline (median 14 days after HIV infection) compared to control (p = 0.0014), as well as chronic subjects (p = 0.0023). A similar tCHO/CR elevation was noted in OGM; no other metabolite abnormalities were seen between acute and control subjects. Mixed longitudinal models revealed resolution of BG tCHO/CR elevation after ART (p = 0.022) with tCHO/CR similar to control subjects at 6 months. Interpretation We detected cellular inflammation in the absence of measurable neuronal injury within the first month of HIV infection, and normalization of this inflammation following acutely administered ART. Our findings suggest that early ART may be neuroprotective in HIV infection by mitigating processes leading to CNS injury

Modeling neurocognitive and neurobiological recovery in addiction

This book focuses on "what to know" and "how to apply" information, prioritizing novel principles and delineating cutting-edge assessment, phenotyping and treatment tools

Big GABA II: Water-referenced edited MR spectroscopy at 25 research sites

Accurate and reliable quantification of brain metabolites measured in vivo using 1H magnetic resonance spectroscopy (MRS) is a topic of continued interest. Aside from differences in the basic approach to quantification, the quantification of metabolite data acquired at different sites and on different platforms poses an additional methodological challenge. In this study, spectrally edited γ-aminobutyric acid (GABA) MRS data were analyzed and GABA levels were quantified relative to an internal tissue water reference. Data from 284 volunteers scanned across 25 research sites were collected using GABA+ (GABA + co-edited macromolecules (MM)) and MM-suppressed GABA editing. The unsuppressed water signal from the volume of interest was acquired for concentration referencing. Whole-brain T1-weighted structural images were acquired and segmented to determine gray matter, white matter and cerebrospinal fluid voxel tissue fractions. Water-referenced GABA measurements were fully corrected for tissue-dependent signal relaxation and water visibility effects. The cohort-wide coefficient of variation was 17% for the GABA + data and 29% for the MM-suppressed GABA data. The mean within-site coefficient of variation was 10% for the GABA + data and 19% for the MM-suppressed GABA data. Vendor differences contributed 53% to the total variance in the GABA + data, while the remaining variance was attributed to site- (11%) and participant-level (36%) effects. For the MM-suppressed data, 54% of the variance was attributed to site differences, while the remaining 46% was attributed to participant differences. Results from an exploratory analysis suggested that the vendor differences were related to the unsuppressed water signal acquisition. Discounting the observed vendor-specific effects, water-referenced GABA measurements exhibit similar levels of variance to creatine-referenced GABA measurements. It is concluded that quantification using internal tissue water referencing is a viable and reliable method for the quantification of in vivo GABA levels

Dopamine and Glutamate in Antipsychotic-Responsive Compared With Antipsychotic-Nonresponsive Psychosis: A Multicenter Positron Emission Tomography and Magnetic Resonance Spectroscopy Study (STRATA)

The variability in the response to antipsychotic medication in schizophrenia may reflect between-patient differences in neurobiology. Recent cross-sectional neuroimaging studies suggest that a poorer therapeutic response is associated with relatively normal striatal dopamine synthesis capacity but elevated anterior cingulate cortex (ACC) glutamate levels. We sought to test whether these measures can differentiate patients with psychosis who are antipsychotic responsive from those who are antipsychotic nonresponsive in a multicenter cross-sectional study. 1H-magnetic resonance spectroscopy (1H-MRS) was used to measure glutamate levels (Glucorr) in the ACC and in the right striatum in 92 patients across 4 sites (48 responders [R] and 44 nonresponders [NR]). In 54 patients at 2 sites (25 R and 29 NR), we additionally acquired 3,4-dihydroxy-6-[18F]fluoro-L-phenylalanine (18F-DOPA) positron emission tomography (PET) to index striatal dopamine function (Kicer, min−1). The mean ACC Glucorr was higher in the NR than the R group after adjustment for age and sex (F1,80 = 4.27; P = .04). This was associated with an area under the curve for the group discrimination of 0.59. There were no group differences in striatal dopamine function or striatal Glucorr. The results provide partial further support for a role of ACC glutamate, but not striatal dopamine synthesis, in determining the nature of the response to antipsychotic medication. The low discriminative accuracy might be improved in groups with greater clinical separation or increased in future studies that focus on the antipsychotic response at an earlier stage of the disorder and integrate other candidate predictive biomarkers. Greater harmonization of multicenter PET and 1H-MRS may also improve sensitivity

Significant Effects of Antiretroviral Therapy on Global Gene Expression in Brain Tissues of Patients with HIV-1-Associated Neurocognitive Disorders

Antiretroviral therapy (ART) has reduced morbidity and mortality in HIV-1 infection; however HIV-1-associated neurocognitive disorders (HAND) persist despite treatment. The reasons for the limited efficacy of ART in the brain are unknown. Here we used functional genomics to determine ART effectiveness in the brain and to identify molecular signatures of HAND under ART. We performed genome-wide microarray analysis using Affymetrix U133 Plus 2.0 Arrays, real-time PCR, and immunohistochemistry in brain tissues from seven treated and eight untreated HAND patients and six uninfected controls. We also determined brain virus burdens by real-time PCR. Treated and untreated HAND brains had distinct gene expression profiles with ART transcriptomes clustering with HIV-1-negative controls. The molecular disease profile of untreated HAND showed dysregulated expression of 1470 genes at p<0.05, with activation of antiviral and immune responses and suppression of synaptic transmission and neurogenesis. The overall brain transcriptome changes in these patients were independent of histological manifestation of HIV-1 encephalitis and brain virus burdens. Depending on treatment compliance, brain transcriptomes from patients on ART had 83% to 93% fewer dysregulated genes and significantly lower dysregulation of biological pathways compared to untreated patients, with particular improvement indicated for nervous system functions. However a core of about 100 genes remained similarly dysregulated in both treated and untreated patient brain tissues. These genes participate in adaptive immune responses, and in interferon, cell cycle, and myelin pathways. Fluctuations of cellular gene expression in the brain correlated in Pearson's formula analysis with plasma but not brain virus burden. Our results define for the first time an aberrant genome-wide brain transcriptome of untreated HAND and they suggest that antiretroviral treatment can be broadly effective in reducing pathophysiological changes in the brain associated with HAND. Aberrantly expressed transcripts common to untreated and treated HAND may contribute to neurocognitive changes defying ART