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While COVID-19 research has seen an explosion in the literature, the impact of pandemic-related societal and lifestyle disruptions on brain health among the uninfected remains underexplored. However, a global increase in the prevalence of fatigue, brain fog, depression and other "sickness behavior"-like symptoms implicates a possible dysregulation in neuroimmune mechanisms even among those never infected by the virus. We compared fifty-seven 'Pre-Pandemic' and fifteen 'Pandemic' datasets from individuals originally enrolled as control subjects for various completed, or ongoing, research studies available in our records, with a confirmed negative test for SARS-CoV-2 antibodies. We used a combination of multimodal molecular brain imaging (simultaneous positron emission tomography / magnetic resonance spectroscopy), behavioral measurements, imaging transcriptomics and serum testing to uncover links between pandemic-related stressors and neuroinflammation. Healthy individuals examined after the enforcement of 2020 lockdown/stay-at-home measures demonstrated elevated brain levels of two independent neuroinflammatory markers (the 18 kDa translocator protein, TSPO, and myoinositol) compared to pre-lockdown subjects. The serum levels of two inflammatory markers (interleukin-16 and monocyte chemoattractant protein-1) were also elevated, although these effects did not reach statistical significance after correcting for multiple comparisons. Subjects endorsing higher symptom burden showed higher TSPO signal in the hippocampus (mood alteration, mental fatigue), intraparietal sulcus and precuneus (physical fatigue), compared to those reporting little/no symptoms. Post-lockdown TSPO signal changes were spatially aligned with the constitutive expression of several genes involved in immune/neuroimmune functions. This work implicates neuroimmune activation as a possible mechanism underlying the non-virally-mediated symptoms experienced by many during the COVID-19 pandemic. Future studies will be needed to corroborate and further interpret these preliminary findings.

Whether brain matter volume is correlated with cognitive functioning and higher intelligence is controversial. We explored this relationship by analysis of data collected on 193 healthy young and older adults through the "Leipzig Study for Mind-Body-Emotion Interactions" (LEMON) study. Our analysis involved four cognitive measures: fluid intelligence, crystallized intelligence, cognitive flexibility, and working memory. Brain subregion volumes were determined by magnetic resonance imaging. We normalized each subregion volume to the estimated total intracranial volume and conducted training simulations to compare the predictive power of normalized volumes of large regions of the brain (i.e., gray matter, cortical white matter, and cerebrospinal fluid), normalized subcortical volumes, and combined normalized volumes of large brain regions and normalized subcortical volumes. Statistical tests showed significant differences in the performance accuracy and feature importance of the subregion volumes in predicting cognitive skills for young and older adults. Random forest feature selection analysis showed that cortical white matter was the key feature in predicting fluid intelligence in both young and older adults. In young adults, crystallized intelligence was best predicted by caudate nucleus, thalamus, pallidum, and nucleus accumbens volumes, whereas putamen, amygdala, nucleus accumbens, and hippocampus volumes were selected for older adults. Cognitive flexibility was best predicted by the caudate, nucleus accumbens, and hippocampus in young adults and caudate and amygdala in older adults. Finally, working memory was best predicted by the putamen, pallidum, and nucleus accumbens in the younger group, whereas amygdala and hippocampus volumes were predictive in the older group. Thus, machine learning predictive models demonstrated an age-dependent association between subcortical volumes and cognitive measures. These approaches may be useful in predicting the likelihood of age-related cognitive decline and in testing of approaches for targeted improvement of cognitive functioning in older adults. ispartof: HUMAN BRAIN MAPPING vol:44 issue:2 pages:801-812 ispartof: location:United States status: published

BACKGROUND: Patients with recurrent glioblastoma (GBM) are often treated with antiangiogenic agents, such as bevacizumab (BEV). Despite therapeutic promise, conventional MRI methods fail to help determine which patients may not benefit from this treatment. PURPOSE: To use MR spectroscopic imaging (MRSI) with intermediate and short echo time to measure corrected myo-inositol (mI)normalized by contralateral creatine (hereafter, mI/c-Cr) in participants with recurrent GBM treated with BEV and to investigate whether such measurements can help predict survivorship before BEV initiation (baseline) and at 1 day, 4 weeks, and 8 weeks thereafter. MATERIALS AND METHODS: In this prospective longitudinal study (2016–2020), spectroscopic data on mI—a glial marker and osmoregulator within the brain—normalized by contralateral creatine in the intratumoral, contralateral, and peritumoral volumes of patients with recurrent GBM were evaluated. Area under the receiver operating characteristic curve (AUC) was calculated for all volumes at baseline and 1 day, 4 weeks, and 8 weeks after treatment to determine the ability of mI/c-Cr to help predict survivorship. RESULTS: Twenty-one participants (median age ± standard deviation, 62 years ± 12; 15 men) were evaluated. Lower mI/c-Cr in the tumor before and during BEV treatment was predictive of poor survivorship, with receiver operating characteristic analyses showing an AUC of 0.75 at baseline, 0.87 at 1 day after treatment, and 1 at 8 weeks after. A similar result was observed in contralateral normal-appearing tissue and the peritumoral volume, with shorter-term survivors having lower levels of mI/c-Cr. In the contralateral volume, a lower ratio of mI to creatine (hereafter, mI/Cr) predicted shorter-term survival at baseline and all other time points. Within the peritumoral volume, lower mI/c-Cr levels were predictive of shorter-term survival at baseline (AUC, 0.80), at 1 day after treatment (AUC, 0.93), and at 4 weeks after treatment (AUC, 0.68). CONCLUSION: Lower levels of myo-inositol normalized by contralateral creatine within intratumoral, contralateral, and peritumoral volumes were predictive of poor survivorship and antiangiogenic treatment failure as early as before bevacizumab treatment. Adapting MR spectroscopic imaging alongside conventional MRI modalities conveys critical information regarding the biologic characteristics of tumors to help better treat individuals with recurrent glioblastoma. Clinical trial registration no. NCT02843230 © RSNA, 2021 Online supplemental material is available for this article.

Magnetic resonance spectroscopy (MRS) and functional MRI (fMRI), related through common biophysical bases, provide complementary information about brain function. The link between MRS and fMRI measures is of interest, especially in the ultra-rare, metabolic disease late-onset GM2 gangliosidosis (LOGG). Imaging studies on LOGG have been few and far between, with cerebellar atrophy and neurochemical impairments being the most prominent findings. However, it remains unknown as to how these neurochemical aberrations relate to neurofunctional characteristics. The goal of this study (7 LOGG, 7 age/sex matched controls) was to assess the relationship between MRS concentrations and fMRI measures derived from the same MRS ROI (cerebellum, thalamus, precuneus) in LOGG. To quantify the communication between MRS regions and rest of the brain, we employed graph measures estimated from resting-state fMRI functional connectivity. We found that one such measure, local efficiency, which quantifies the aggregate relationship between a MRS region and rest of the brain, was significantly associated with N-acetylaspartate (NAA) in the cerebellum and thalamus (pp=0.002). These findings hint at a model of impaired neurochemical concentrations in these regions, leading to aberrant communication between them and rest of the brain, which may exacerbate disease progression. Future research must replicate these findings in larger cohorts, and further investigate such abnormalities in the cerebellum, thalamus and precuneus in this ultra-rare neurological disease.

BACKGROUND Fibromyalgia is a centralized multidimensional chronic pain syndrome, but its pathophysiology is not fully understood. METHODS We applied 3D magnetic resonance spectroscopic imaging (MRSI), covering multiple cortical and subcortical brain regions, to investigate the association between neuro-metabolite (e.g. combined glutamate and glutamine, Glx; myo-inositol, mIno; and combined (total) N-acetylaspartate and N-acetylaspartylglutamate, tNAA) levels and multidimensional clinical/behavioural variables (e.g. pain catastrophizing, clinical pain severity and evoked pain sensitivity) in women with fibromyalgia (N = 87). RESULTS Pain catastrophizing scores were positively correlated with Glx and tNAA levels in insular cortex, and negatively correlated with mIno levels in posterior cingulate cortex (PCC). Clinical pain severity was positively correlated with Glx levels in insula and PCC, and with tNAA levels in anterior midcingulate cortex (aMCC), but negatively correlated with mIno levels in aMCC and thalamus. Evoked pain sensitivity was negatively correlated with levels of tNAA in insular cortex, MCC, PCC and thalamus. CONCLUSIONS These findings support single voxel placement targeting nociceptive processing areas in prior 1 H-MRS studies, but also highlight other areas not as commonly targeted, such as PCC, as important for chronic pain pathophysiology. Identifying target brain regions linked to multidimensional symptoms of fibromyalgia (e.g. negative cognitive/affective response to pain, clinical pain, evoked pain sensitivity) may aid the development of neuromodulatory and individualized therapies. Furthermore, efficient multi-region sampling with 3D MRSI could reduce the burden of lengthy scan time for clinical research applications of molecular brain-based mechanisms supporting multidimensional aspects of fibromyalgia. SIGNIFICANCE This large N study linked brain metabolites and pain features in fibromyalgia patients, with a better spatial resolution and brain coverage, to understand a molecular mechanism underlying pain catastrophizing and other aspects of pain transmission. Metabolite levels in self-referential cognitive processing area as well as pain-processing regions were associated with pain outcomes. These results could help the understanding of its pathophysiology and treatment strategies for clinicians.

Brain lesions caused by Cryptococcus neoformans or C. gattii (cryptococcomas) are typically difficult to diagnose correctly and treat effectively, but rapid differential diagnosis and treatment initiation are crucial for good outcomes. In previous studies, cultured cryptococcal isolates and ex vivo lesion material contained high concentrations of the virulence factor and fungal metabolite trehalose. Here, we studied the in vivo metabolic profile of cryptococcomas in the brain using magnetic resonance spectroscopy (MRS) and assessed the relationship between trehalose concentration, fungal burden, and treatment response in order to validate its suitability as marker for early and noninvasive diagnosis and its potential to monitor treatment in vivo. We investigated the metabolites present in early and late stage cryptococcomas using in vivo 1H MRS in a murine model and evaluated changes in trehalose concentrations induced by disease progression and antifungal treatment. Animal data were compared to 1H and 13C MR spectra of Cryptococcus cultures and in vivo data from 2 patients with cryptococcomas in the brain. In vivo MRS allowed the noninvasive detection of high concentrations of trehalose in cryptococcomas and showed a comparable metabolic profile of cryptococcomas in the murine model and human cases. Trehalose concentrations correlated strongly with the fungal burden. Treatment studies in cultures and animal models showed that trehalose concentrations decrease following exposure to effective antifungal therapy. Although further cases need to be studied for clinical validation, this translational study indicates that the noninvasive MRS-based detection of trehalose is a promising marker for diagnosis and therapeutic follow-up of cryptococcomas.

Aging is associated with alterations in the brain including structural and metabolic changes. Previous research has focused on neurometabolite level differences associated to age in a variety of brain regions, but the relationship among metabolites across the brain has been much less studied. Investigating these relationships can reveal underlying neurometabolic processes, their interdependency, and their progress throughout the lifespan. Using

BACKGROUND Recurrent glioblastoma (rGBM) patients are often treated with anti-angiogenic agents such as bevacizumab (BEV). Despite therapeutic promise, conventional MR methods fail to determine which patients may not benefit. PURPOSE: The purpose of this study was to utilize magnetic resonance spectroscopic imaging (MRSI) with intermediate and short echo time to generate corrected Myo-inositol normalized by contralateral creatine (mI/c-Cr) in patients with rGBM treated with BEV and investigate whether it can predict survivorship prior to BEV initiation (baseline) and at 1-day, 4-weeks, and 8-weeks thereafter. METHODS We conducted a prospective, longitudinal study and evaluated spectroscopic data of myo-inositol (mI), a glial marker and osmoregulator within the brain, normalized to contralateral-creatine (mI/c-Cr) in the intratumoral, contralateral normal appearing white matter, and peritumoral volumes of rGBM patients. Area under the ROC curve (AUC) was calculated for all volumes at baseline, 1-day, 4-weeks, and 8-weeks after treatment to determine mI/c-Cr’s ability to predict survivorship. RESULTS 21 participants (62 ± 12 years, 15 men) were evaluated. Lower mI/c-Cr in the tumor prior to and during BEV treatment predicted poor survivorship, with ROC analyses illustrating an AUC of 0.75 at baseline, 0.87 at 1-day, and 1 at 8 weeks. Lower levels of mI/c-Cr were also observed in the contralateral and the peritumoral volumes for shorter-term survivors. In the contralateral volume, lower mI/Cr was predictive of shorter-term survival at baseline and all other timepoints. Within the peritumoral volume, lower mI/c-Cr was predictive of shorter-term survival at baseline (AUC=0.80), 1-day (AUC=0.93), and 4-weeks (AUC=0.68). CONCLUSIONS Lower levels of mI/c-Cr within intratumoral, contralateral, and peritumoral volumes were predictive of poor survivorship and anti-angiogenic treatment failure as early as one month before BEV treatment. Acquiring MRSI alongside conventional MR imaging modalities can convey critical information regarding tumor microenvironment that informs management of patients with rGBM.

SummaryBackgroundThe impact of COVID-19 on human health extends beyond the morbidity and death toll directly caused by the SARS-CoV-2 virus. In fact, accumulating evidence indicates a global increase in the incidence of fatigue, brain fog and depression, including among non-infected, since the pandemic onset. Motivated by previous evidence linking those symptoms to neuroimmune activation in other pathological contexts, we hypothesized that subjects examined after the enforcement of lockdown/stay-at-home measures would demonstrate increased neuroinflammation.MethodsWe performed simultaneous brain Positron Emission Tomography / Magnetic Resonance Imaging in healthy volunteers either before (n=57) or after (n=15) the 2020 Massachusetts lockdown, using [11C]PBR28, a radioligand for the glial marker 18 kDa translocator protein (TSPO). First, we compared [11C]PBR28 signal across pre- and post-lockdown cohorts. Then, we evaluated the link between neuroinflammatory signals and scores on a questionnaire assessing mental and physical impacts of the pandemic. Further, we investigated multivariate associations between the spatial pattern of [11C]PBR28 post-lockdown changes and constitutive brain gene expression in post-mortem brains (Allen Human Brain Atlas). Finally, in a subset (n=13 pre-lockdown; n=11 post-lockdown), we also used magnetic resonance spectroscopy to quantify brain (thalamic) levels of myoinositol (mIns), another neuroinflammatory marker.FindingsBoth [11C]PBR28 and mIns signals were overall stable pre-lockdown, but markedly elevated after lockdown, including within brain regions previously implicated in stress, depression and “sickness behaviors”. Moreover, amongst the post-lockdown cohort, subjects endorsing higher symptom burden showed higher [11C]PBR28 PET signal compared to those reporting little/no symptoms. Finally, the post-lockdown [11C]PBR28 signal changes were spatially aligned with the constitutive expression of several genes highly expressed in glial/immune cells and/or involved in neuroimmune signaling.InterpretationOur results suggest that pandemic-related stressors may have induced sterile neuroinflammation in healthy individuals that were not infected with SARS-CoV-2. This work highlights the possible impact of the COVID-19 pandemic-related lifestyle disruptions on human brain health.FundingR01-NS094306-01A1, R01-NS095937-01A1, R01-DA047088-01, The Landreth Family Foundation.

Objective Our study aimed to quantify structural changes in relation to metabolic abnormalities in the cerebellum, thalamus, and parietal cortex of patients with late-onset GM2-gangliosidosis (LOGG), which encompasses late-onset Tay-Sachs disease (LOTS) and Sandhoff disease (LOSD). Methods We enrolled 10 patients with LOGG (7 LOTS, 3 LOSD) who underwent a neurological assessment battery and 7 age-matched controls. Structural MRI and MRS were performed on a 3 T scanner. Structural volumes were obtained from FreeSurfer and normalized by total intracranial volume. Quantified metabolites included N-acetylaspartate (NAA), choline (Cho), myo-inositol (mI), creatine (Cr), and combined glutamate-glutamine (Glx). Metabolic concentrations were corrected for partial volume effects. Results Structural analyses revealed significant cerebellar atrophy in the LOGG cohort, which was primarily driven by LOTS patients. NAA was lower and mI higher in LOGG, but this was also significantly driven by the LOTS patients. Clinical ataxia deficits (via the Scale for the Assessment and Rating of Ataxia) were associated with neuronal injury (via NAA), neuroinflammation (via mI), and volumetric atrophy in the cerebellum. Interpretation The decrease of NAA in the cerebellum suggests that, in addition to cerebellar atrophy, there is ongoing impaired neuronal function and/or loss, while an increase in mI indicates possible neuroinflammation in LOGG (more so within the LOTS subvariant). Quantifying cerebellar atrophy in relation to neurometabolic differences in LOGG may lead to improvements in assessing disease severity, progression, and pharmacological efficacy. Lastly, additional neuroimaging studies in LOGG are required to contrast LOTS and LOSD more accurately.

Zuzana Skubalova,1,2 Simona Rex,1,2 Martina Sukupova,1 Martin Zahalka,1 Petr Skladal,3 Jan Pribyl,3 Hana Michalkova,1,2 Akila Weerasekera,4 Vojtech Adam,1,2 Zbynek Heger1,2 1Department of Chemistry and Biochemistry, Mendel University in Brno, Brno, Czech Republic; 2Central European Institute of Technology, Brno University of Technology, Brno, Czech Republic; 3Central European Institute of Technology, Masaryk University, Brno, Czech Republic; 4Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Harvard Medical School, Charlestown, MA, USACorrespondence: Zbynek HegerDepartment of Chemistry and Biochemistry, Mendel University in Brno, Zemedelska 1, Brno CZ-613 00, Czech RepublicTel +420-5-4513-3350Fax +420-5-4521-2044Email heger@mendelu.czIntroduction: The present study reports on examination of the effects of encapsulating the tyrosine kinase inhibitors (TKIs) vandetanib and lenvatinib into a biomacromolecular ferritin-based delivery system.Methods: The encapsulation of TKIs was performed via two strategies: i) using an active reversible pH-dependent reassembly of ferritin´s quaternary structure and ii) passive loading of hydrophobic TKIs through the hydrophobic channels at the junctions of ferritin subunits. After encapsulation, ferritins were surface-functionalized with folic acid promoting active-targeting capabilities.Results: The physico-chemical and nanomechanical analyses revealed that despite the comparable encapsulation efficiencies of both protocols, the active loading affects stability and rigidity of ferritins, plausibly due to their imperfect reassembly. Biological experiments with hormone-responsive breast cancer cells (T47-D and MCF-7) confirmed the cytotoxicity of encapsulated and folate-targeted TKIs to folate-receptor positive cancer cells, but only limited cytotoxic effects to healthy breast epithelium. Importantly, the long-term cytotoxic experiments revealed that compared to the pH-dependent encapsulation, the passively-loaded TKIs exert markedly higher anticancer activity, most likely due to undesired influence of harsh acidic environment used for the pH-dependent encapsulation on the TKIs’ structural and functional properties.Conclusion: Since the passive loading does not require a reassembly step for which acids are needed, the presented investigation serves as a solid basis for future studies focused on encapsulation of small hydrophobic molecules.Keywords: drug delivery, nanomedicine, lenvatinib, vandetanib

The weak association between disability levels and "peripheral" (ie, knee) findings suggests that central nervous system alterations may contribute to the pathophysiology of knee osteoarthritis (KOA). Here, we evaluated brain metabolite alterations in patients with KOA, before and after total knee arthroplasty (TKA), using 1H-magnetic resonance spectroscopy (MRS). Thirty-four presurgical patients with KOA and 13 healthy controls were scanned using a PRESS sequence (TE = 30 ms, TR = 1.7 seconds, voxel size = 15 × 15 × 15 mm). In addition, 13 patients were rescanned 4.1 ± 1.6 (mean ± SD) weeks post-TKA. When using creatine (Cr)-normalized levels, presurgical KOA patients demonstrated lower N-acetylaspartate (NAA) (P0.001), higher myoinositol (mIns) (P0.001), and lower Choline (Cho) (P0.05) than healthy controls. The mIns levels were positively correlated with pain severity scores (r = 0.37, P0.05). These effects reached statistical significance also using water-referenced concentrations, except for the Cho group differences (P ≥ 0.067). Post-TKA patients demonstrated an increase in NAA (P0.01), which returned to the levels of healthy controls (P0.05), irrespective of metric. In addition, patients demonstrated postsurgical increases in Cr-normalized (P0.001), but not water-referenced mIns, which were proportional to the NAA/Cr increases (r = 0.61, P0.05). Because mIns is commonly regarded as a glial marker, our results are suggestive of a possible dual role for neuroinflammation in KOA pain and post-TKA recovery. Moreover, the apparent postsurgical normalization of NAA, a putative marker of neuronal integrity, might implicate mitochondrial dysfunction, rather than neurodegenerative processes, as a plausible pathophysiological mechanism in KOA. More broadly, our results add to a growing body of literature suggesting that some pain-related brain alterations can be reversed after peripheral surgical treatment.

Currently TAR DNA binding protein 43 (TDP-43) pathology, underlying Amyotrophic Lateral Sclerosis (ALS), remains poorly understood which hinders both clinical diagnosis and drug discovery efforts. To better comprehend the disease pathophysiology, positron emission tomography (PET) and multi-parametric magnetic resonance imaging (mp-MRI) provide a non-invasive mode to investigate molecular, structural, and neurochemical abnormalities in vivo. For the first time, we report the findings of a longitudinal PET-MR study in the TDP-43A315T ALS mouse model, investigating disease-related changes in the mouse brain. 2-deoxy-2-[18F]fluoro-D-glucose [18F]FDG PET showed significantly lowered glucose metabolism in the motor and somatosensory cortices of TDP-43A315T mice whereas metabolism was elevated in the region covering the bilateral substantia nigra, reticular and amygdaloid nucleus between 3 and 7 months of age, as compared to non-transgenic controls. MR spectroscopy data showed significant changes in glutamate + glutamine (Glx) and choline levels in the motor cortex and hindbrain of TDP-43A315T mice compared to controls. Cerebral blood flow (CBF) measurements, using an arterial spin labelling approach, showed no significant age- or group-dependent changes in brain perfusion. Diffusion MRI indices demonstrated transient changes in different motor areas of the brain in TDP-43A315T mice around 14 months of age. Cytoplasmic TDP-43 proteinaceous inclusions were observed in the brains of symptomatic, 18-month-old mice, but not in non-symptomatic transgenic or wild-type mice. Our results reveal that disease- and age-related functional and neurochemical alterations, together with limited structural changes, occur in specific brain regions of transgenic TDP-43A315T mice, as compared to their healthy counterparts. Altogether these findings shed new light on TDP-43A315T disease pathogenesis and may prove useful for clinical management of ALS. ispartof: Neuroimage-Clinical vol:27 ispartof: location:Netherlands status: published

Suboptimal inhibitory control is a major factor contributing to motor/cognitive deficits in older age and pathology. Here, we provide novel insights into the neurochemical biomarkers of inhibitory control in healthy young and older adults and highlight putative neurometabolic correlates of deficient inhibitory functions in normal aging. Age-related alterations in levels of glutamate–glutamine complex (Glx), N-acetylaspartate (NAA), choline (Cho), and myo-inositol (mIns) were assessed in the right inferior frontal gyrus (RIFG), pre-supplementary motor area (preSMA), bilateral sensorimotor cortex (SM1), bilateral striatum (STR), and occipital cortex (OCC) with proton magnetic resonance spectroscopy (1H-MRS). Data were collected from 30 young (age range 18–34 years) and 29 older (age range 60–74 years) adults. Associations between age-related changes in the levels of these metabolites and performance measures or reactive/proactive inhibition were examined for each age group. Glx levels in the right striatum and preSMA were associated with more efficient proactive inhibition in young adults but were not predictive for reactive inhibition performance. Higher NAA/mIns ratios in the preSMA and RIFG and lower mIns levels in the OCC were associated with better deployment of proactive and reactive inhibition in older adults. Overall, these findings suggest that altered regional concentrations of NAA and mIns constitute potential biomarkers of suboptimal inhibitory control in aging.

Brain multivoxel MR spectroscopic imaging was performed in 3 consecutive patients with coronavirus disease 2019 (COVID-19). These included 1 patient with COVID-19-associated necrotizing leukoencephalopathy, another patient who had a recent pulseless electrical activity cardiac arrest with subtle white matter changes, and a patient without frank encephalopathy or a recent severe hypoxic episode. The MR spectroscopic imaging findings were compared with those of 2 patients with white matter pathology not related to Severe Acute Respiratory Syndrome coronavirus 2 infection and a healthy control subject. The NAA reduction, choline elevation, and glutamate/glutamine elevation found in the patient with COVID-19-associated necrotizing leukoencephalopathy and, to a lesser degree, the patient with COVID-19 postcardiac arrest, follow a similar pattern as seen with the patient with delayed posthypoxic leukoencephalopathy. Lactate elevation was most pronounced in the patient with COVID-19 necrotizing leukoencephalopathy.

In a longitudinal rat model of alcohol consumption, we showed that exposure to alcohol decreased the concentration of glutamate in the prefrontal cortex, whereas a normalization occurred during abstinence. 18F-FPEB PET scans revealed that pre-exposure mGluR5 availability in the nucleus accumbens was associated with future alcohol preference. Finally, alcohol exposure induced a decrease in mGluR5 availability in the bilateral hippocampus and amygdala compared with baseline, and in the hippocampus and striatum compared with saccharin (Figure). ispartof: ADDICTION BIOLOGY vol:24 issue:4 pages:696-706 ispartof: location:United States status: published

Cocaine addiction is a disorder that still lacks diagnostic biomarkers or effective pharmacotherapy. We present findings in a rat model of cocaine self-administration that was followed-up longitudinally using the metabotropic glutamate receptor 5 (mGluR5) tracer 18F-FPEB positron emission tomography (PET), proton magnetic resonance spectroscopy (1H-MRS) and behavioral tests. Methods: Forty-two Wistar rats were scanned with 18F-FPEB PET and 1H-MRS before and after sucrose or IV cocaine self-administration, during withdrawal and relapse. All animals performed a rodent Iowa Gambling Task (rIGT) at baseline to evaluate decision-making. Baseline values were used in a mixed model to assess associations with later cocaine use and follow-up measurements were compared to the values before drug exposure. Results: Pre-exposure rIGT scores were significantly related to both cocaine and sucrose use during the drug-exposure phase. However, only cocaine self-administration induced a decrease in 18F-FPEB binding. This decrease was most pronounced in the bilateral hippocampus, where mGluR5 availability correlated with the amount of cocaine used during relapse. Compared to the sucrose group, a larger decrease was observed in the hippocampo-prefrontal cortex pathway. Pre-exposure glutamate and glycine concentrations in the prefrontal cortex were significantly associated with cocaine use during the drug-exposure phase. Moreover, prefrontal glutamate exhibited a distinct, reversible decrease when animals had access to cocaine, but not sucrose. Conclusion: Baseline values of prefrontal glutamate and glycine are associated with future cocaine use. Furthermore, baseline rIGT scores are associated with both sucrose and cocaine. Finally, we found that both glutamate concentration and mGluR5 availability decrease during exposure to cocaine. ispartof: Journal of Nuclear Medicine vol:59 issue:6 pages:952-959 ispartof: location:United States status: published

Converging preclinical evidence links extrastriatal dopamine release and glutamatergic transmission via the metabotropic glutamate receptor 5 (mGluR5) to the rewarding properties of alcohol. To date, human evidence is lacking on how and where in the brain these processes occur. Mesocorticolimbic dopamine release upon intravenous alcohol administration and mGluR5 availability were measured in 11 moderate social drinkers by single-session [18F]fallypride and [18F]FPEB positron emission tomography, respectively. Additionally, baseline and postalcohol glutamate and glutamine levels in the anterior cingulate cortex (ACC) were measured by using proton-magnetic resonance spectroscopy. To investigate differences in reward domains linked to both neurotransmitters, regional imaging data were related to subjective alcohol responses. Alcohol induced significant [18F]fallypride displacement in the prefrontal cortex (PFC), temporal and parietal cortices and thalamus (P

Recently, several promising treatments for high-grade gliomas (HGGs) failed to provide significant benefit when translated from the preclinical setting to patients. Improving the animal models is fundamental to overcoming this translational gap. To address this need, we developed and comprehensively characterized a new in vivo model based on the orthotopic implantation of CT-2A cells cultured in neurospheres (NS/CT-2A). Murine CT-2A methylcholanthrene-induced HGG cells (C57BL/6 background) were cultured in monolayers (ML) or NS and orthotopically inoculated in syngeneic animals. ML/CT-2A and NS/CT-2A tumors’ characterization included the analysis of tumor growth, immune microenvironment, glioma stem cells (GSCs), vascularization and metabolites. The immuno-modulating properties of NS/CT-2A and ML/CT-2A cells on splenocytes were tested in vitro. Mice harboring NS/CT-2A tumors had a shorter survival than those harboring ML/CT-2A tumors (P=0.0033). Compared to standard ML/CT-2A tumors, NS/CT-2A tumors showed more abundant GSCs (P=0.0002 and 0.0770 for Nestin and CD133, respectively) and regulatory T cells (Tregs, P=0.0074), and a strong tendency towards an increased vascularization (P=0.0503). There were no significant differences in metabolites’ composition between NS/ and ML/CT-2A tumors. In vitro, NS were able to drive splenocytes towards a more immunosuppressive status by reducing CD8+ T cells (P=0.0354) and by promoting Tregs (P=0.0082), macrophages (MF, P=0.0019) and their M2 subset (P=0.0536). Compared to standard ML/CT-2A tumors, NS/CT-2A tumors show a more aggressive phenotype with increased immunosuppression and GSCs proliferation. Because of these specific features, the NS/CT-2A model represents a clinically relevant platform in the search for new HGG treatments aimed at reducing immunosuppression and eliminating GSCs., SCOPUS: ar.j, info:eu-repo/semantics/published

Fibromyalgia is a multidimensional chronic pain syndrome. It is thought to result mainly from central nervous system dysfunction, but its working mechanism is not fully understood. In this study, we applied multi-slice magnetic resonance spectroscopy imaging (MRSI) to investigate the relationship between brain metabolite (e.g., combined glutamate and glutamine, Glx; myo-inositol, mIno; and combined N-acetylaspartate and N-acetylaspartylglutamate; tNAA) levels and the severity of multidimensional clinical/behavioral metrics (e.g., pain catastrophizing, clinical pain severity, and evoked pain sensitivity) in fibromyalgia patients (N=87). Fibromyalgia patients showed greater pain catastrophizing and hyperalgesia compared with age-matched healthy controls (N=40). In fibromyalgia patients, pain catastrophizing scale scores were positively correlated with Glx and tNAA levels in the insular cortex, and were negatively correlated with mIno levels in the posterior cingulate cortex (PCC). Clinical pain severity showed positive correlations with Glx levels in the insular and PCC, and with tNAA levels in the anterior middle cingulate cortex (aMCC), but negatively with mIno levels in the aMCC and thalamus. The level of tNAA in the insular cortex, MCC, PCC, and thalamus, were negatively correlated with evoked pain sensitivity. These results highlight the utility of MRSI in the understanding of molecular mechanisms underlying multidimensional aspects of fibromyalgia. This work was supported by the NIH (National Institute of Arthritis and Musculoskeletal and Skin Diseases grant R01-AR064367, National Center for Complementary and Integrative Health grants R01-AT007550, R61-AT009306, and P01-AT AT009965, and National Center for Research Resources grants P41-RR14075, S10-RR021110, and S10-RR023043). Development of MRSI pulse sequence and processing was funded by NIH/NCI grants K22CA178269 and R01CA211080.

The weak association between disability levels and “peripheral” (i.e., knee) findings suggests that central nervous system alterations may contribute to the pathophysiology of knee osteoarthritis (KOA). Here, we evaluated brain metabolite alterations in KOA patients, before and after total knee arthroplasty (TKA), using 1H-magnetic resonance spectroscopy (MRS). Thirty-four pre-surgical KOA patients and 13 healthy controls were scanned using a PRESS sequence (TE=30ms, TR=1.7s, voxel size=15 × 15 × 15mm). Additionally, a subset of patients (n=13) were re-scanned 4.1±1.6 (mean±SD) weeks post-TKA. When using Creatine (Cr)-normalized levels, pre-surgical KOA patients demonstrated lower N-acetylaspartate (NAA) (p≤0.01) and higher myoinositol (mIns) (p≤0.001), compared to healthy controls. The mIns levels were positively correlated with pain severity scores (r=0.37, p 0.05), irrespective of metric. Additionally, patients demonstrated post-surgical increases in Cr-normalized (p

Heritable temperament traits have been linked to several neuropsychiatric illnesses, including disorders associated with metabotropic glutamate receptor 5 (mGluR5) and dopaminergic dysfunctions. Considering its modulating effect on neurotransmission, we hypothesized that cerebral mGluR5 availability is associated with temperament traits in healthy humans. Methods: Forty-four nonsmoking healthy volunteers (mean age +/- SD, 40 +/- 14 y; age range, 22-66 y; 22 women) were included in this cross-sectional investigation. Brain mGluR5 availability was quantified on both a voxel-by-voxel and a volume-of-interest basis using the total distribution volume of the radioligand F-18-3-fluoro-5-[(pyridin-3-yl)ethynyl]benzonitrile (F-18-FPEB) with 90-min dynamic PET and arterial input function. Moreover, glutamate-glutamine concentrations in the anterior cingulate cortex were measured using MR spectroscopy. These measures were related to the temperament traits of the 240-item Cloninger temperament and character inventory using a regression analysis with age and sex as nuisance variables. Results: High novelty-seeking temperament was robustly associated with increased mGluR5 availability in various regions including the thalamus (r = 0.71; the strongest association), amygdala, parahippocampus, insula, anterior and posterior cingulate cortex, and several primary sensory areas (all r > 0.58; P < 0.05, corrected for familywise error). These associations were specific because no correlations were found with other temperament scales or with spectroscopic measures of glutamatergic transmission. Conclusion: Overall, these data posit mGluR5 in key paralimbic areas as a strong determinant of the temperament trait novelty seeking. These data add to our understanding of how brain neurochemistry accounts for the variation in human behavior and strongly support further research on mGluR5 as a potential therapeutic target in neuropsychiatric disorders associated with abnormal novelty-seeking behaviors.

Previous MRI and proton spectroscopy (1H-MRS) studies have revealed impaired neuronal integrity and altered neurometabolite concentrations in the motor cortex of patients with amyotrophic lateral sclerosis (ALS). Here, we aim to use MRI with conventional and novel MRS sequences to further investigate neurometabolic changes in the motor cortex of ALS patients and their relation to clinical parameters. We utilized the novel HERMES (Hadamard Encoding and Reconstruction of MEGA-Edited Spectroscopy) MRS sequence to simultaneously quantify the inhibitory neurotransmitter GABA and antioxidant glutathione in ALS patients (n = 7) and healthy controls (n = 7). In addition, we have also quantified other MRS observable neurometabolites using a conventional point-resolved MR spectroscopy (PRESS) sequence in ALS patients (n = 20) and healthy controls (n = 20). We observed a trend towards decreasing glutathione concentrations in the motor cortex of ALS patients (p = 0.0842). In addition, we detected a 11% decrease in N-acetylaspartate (NAA) (p = 0.025), a 15% increase in glutamate + glutamine (Glx) (p = 0.0084) and a 21% increase in myo-inositol (mIns) (p = 0.0051) concentrations for ALS patients compared to healthy controls. Furthermore, significant positive correlations were found between GABA-NAA (p = 0.0480; Rρ = 0.7875) and NAA-mIns (p = 0.0448; Rρ = −0.4651) levels among the patients. NAA levels in the bulbar-onset patient group were found to be significantly (p = 0.0097) lower compared to the limb-onset group. A strong correlation (p

In a longitudinal rat model of alcohol consumption, we showed that exposure to alcohol decreased the concentration of glutamate in the prefrontal cortex, whereas a normalization occurred during abstinence. 18F-FPEB PET scans revealed that pre-exposure mGluR5 availability in the nucleus accumbens was associated with future alcohol preference. Finally, alcohol exposure induced a decrease in mGluR5 availability in the bilateral hippocampus and amygdala compared with baseline, and in the hippocampus and striatum compared with saccharin (Figure).To study the role of the glutamatergic system in alcohol abuse disorders, we conducted a longitudinal study of alcohol exposure in rats. Rats were followed with

Several lines of evidence point to alterations in glutamatergic signaling in Parkinson's disease (PD) and levodopa-induced dyskinesia (LID), involving the metabotropic glutamate receptor type 5 (mGluR5). Using small-animal positron emission tomography (PET) with [18F]FPEB and proton magnetic resonance spectroscopy, we investigated cerebral changes in the mGluR5 and glutamate/glutamine availability invivo in PD rats and following onset of LIDs. In parallel, behavioral tests were performed. Comparing PD to control rats, mGluR5 binding potential was decreased in a cluster comprising the bilateral caudate-putamen (CP), ipsilateral motor cortex and somatosensory cortex, and the contralateral somatosensory cortex and parietal association cortex, with the most pronounced reduction in the ipsilateral CP. mGluR5 binding potentials were not significantly altered upon levodopa (L-DOPA) treatment. However, following L-DOPA, an increase in relative mGluR5 uptake was present in the contralateral motor cortex and somatosensory cortex. Glutamate and glutamine concentrations did not differ between control and untreated PD rats or between hemispheres. Though, glutamine levels were higher in the contralateral CP of saline- and L-DOPA-treated rats as compared to the ipsilateral side. Relative mGluR5 uptake in the CP of levodopa-treated rats was also found positively correlated with abnormal involuntary movement scores. Conclusively, mGluR5 availability and glutamine concentrations in the CP are involved in PD, whereas mGluR5 availability in cortical regions may be involved in LID pathology.

Converging preclinical evidence links extrastriatal dopamine release and glutamatergic transmission via the metabotropic glutamate receptor 5 (mGluR5) to the rewarding properties of alcohol. To date, human evidence is lacking on how and where in the brain these processes occur. Mesocorticolimbic dopamine release upon intravenous alcohol administration and mGluR5 availability were measured in 11 moderate social drinkers by single-session [

Aging is associated with gradual alterations in the neurochemical characteristics of the brain, which can be assessed in-vivo with proton-magnetic resonance spectroscopy (1H-MRS). However, the impact of these age-related neurochemical changes on functional motor behavior is still poorly understood. Here, we address this knowledge gap and specifically focus on the neurochemical integrity of the left sensorimotor cortex (SM1) and the occipital lobe (OCC), as both regions are main nodes of the visuomotor network underlying bimanual control. 1H-MRS data and performance on a set of bimanual tasks were collected from a lifespan (20–75 years) sample of 86 healthy adults. Results indicated that aging was accompanied by decreased levels of N-acetylaspartate (NAA), glutamate-glutamine (Glx), creatine ​+ ​phosphocreatine (Cr) and myo-inositol (mI) in both regions, and decreased Choline (Cho) in the OCC region. Lower NAA and Glx levels in the SM1 and lower NAA levels in the OCC were related to poorer performance on a visuomotor bimanual coordination task, suggesting that NAA could serve as a potential biomarker for the integrity of the motor system supporting bimanual control. In addition, lower NAA, Glx, and mI levels in the SM1 were found to be correlates of poorer dexterous performance on a bimanual dexterity task. These findings highlight the role for 1H-MRS to study neurochemical correlates of motor performance across the adult lifespan. This work was supported by the KU Leuven Special Research Fund (grant C16/15/070), the Research Foundation – Flanders (FWO; G.089818N), the Excellence of Science grant (EOS, 30446199, MEMODYN), and the Francqui Foundation awarded to SPS and coworkers. AW and UH acknowledge financial support by the EC-FP7 MC ITN ’TRANSACT’ 2012 (No. 316679) and the KU Leuven program financing ‘IMIR’ (PF10/017). BRK acknowledges financial support by European Union’s Horizon 2020 research and innovation programme under the Marie Skłodowska-Curie grant agreement (No. 703490) and a postdoctoral fellowship from the Research Foundation-Flanders (FWO; No 132635). The authors wish to thank Joren Bosman and Jeroen Buvé for assistance with data processing.

Two identical 5'GACG3' tetra-loop motifs with different stem sequences (called H2 and H3) are found in the 5' end region of Moloney Murine Leukemia Virus (MMLV) genomic RNA. They play important roles in RNA dimerization and encapsidation through two identical tetra-loops (5'GACG3') forming a loop-to-loop kissing complex, the smallest RNA kissing complex ever found in nature. We examined the effects of a loop-closing base pair as well as a stem sequence on the conformational stability of the kissing complex. UV melting analysis and gel electrophoresis were performed on eight RNA sequences mimicking the H2 and H3 hairpin tetra-loops with variation in loop-closing base pairs. Our results show that changing the loop-closing base pair from the wildtype (5'A·U3' for H3, 5'U·A3' for H2) to 5'G·C3'/5'C·G3' has significant effect on the stability of the kissing complexes: the substitution to 5'C·G3' significantly decreases both thermal and mechanical stability, while switching to the 5'G·C3' significantly increases the mechanical stability only. The kissing complexes with the wildtype loop-closing base pairs (5'A·U3' for H3 and 5'U·A3' for H2) show different stability when attached to a different stem sequence (H2 stem vs. H3 stem). This suggests that not only the loop-closing base pair itself, but also the stem sequence, affects the conformational stability of the RNA kissing complex.