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[Background]: Obesity proceeds with important physiological and microstructural alterations in the brain, but the precise relationships between the diet and feeding status, its physiological responses, and the observed neuroimaging repercussions, remain elusive. Here, we implemented a mouse model of high fat diet (HFD) feeding to explore specific associations between diet, feeding status, phenotypic and endocrine repercussions, and the resulting microstructural and metabolic alterations in the brain, as detected by diffusion tensor imaging (DTI) and neurochemical metabolic profiling. [Methods]: Brain DTI images were acquired from adult male C57BL6/J mice after 6 weeks of HFD, or standard diet (SD) administrations, both under the fed, and overnight fasted conditions. Metabolomic profiles of the cortex (Ctx), hippocampus (Hipc), and hypothalamus (Hyp) were determined by 1H high-resolution magic angle spinning (HRMAS) spectroscopy, in cerebral biopsies dissected after microwave fixation. Mean diffusivity (MD), fractional anisotropy (FA) maps, and HRMAS profiles were complemented with determinations of phenotypic alterations and plasma levels of appetite-related hormones, measured by indirect calorimetry and multiplex assays, respectively. We used Z-score and alternating least squares scaling (ALSCAL) analysis to investigate specific associations between diet and feeding status, physiological, and imaging parameters. [Results]: HFD induced significant increases in body weight and the plasma levels of glucose and fatty acids in the fed and fasted conditions, as well as higher cerebral MD (Ctx, Hipc, Hyp), FA (Hipc), and mobile saturated fatty acids resonances (Ctx, Hipc, Hyp). Z-score and ASLCAL analysis identified the precise associations between physiological and imaging variables. [Conclusions]: The present study reveals that diet and feeding conditions elicit prominent effects on specific imaging and spectroscopic parameters of the mouse brain that can be associated to the alterations in phenotypic and endocrine variables. Together, present results disclose a neuro-inflammatory response to HFD, characterized primarily by vasogenic edema and compensatory responses in osmolyte concentrations., The authors disclosed receipt of the following financial support for research, authorship, and/or publication of this article; Ministry of Science and Innovation (SAF2017-83043-R), and Community of Madrid (S2017/BMD-3688), both to SC and PLL. IG is a predoctoral fellow of the Ministry of Innovation and Science (BES-2015-075202); BL holds a senior investigator contract from CSIC; PLL, SC, and LB are CSIC staff members.

© 2019 Lizarbe, Fernández-Pérez, Caz, Largo, Vallejo, López-Larrubia and Cerdán., The hypothalamus is the principal regulator of global energy balance, enclosing additionally essential neuronal centers for glucose-sensing and osmoregulation. Disturbances in these tightly regulated neuronal networks are thought to underlie the development of severe pandemic syndromes, including obesity and diabetes. In this work, we investigate in vivo the response of individual hypothalamic nuclei to the i.p. administration of glucose or vehicle solutions, using two groups of adult male C57BL6/J fasted mice and a combination of non-invasive T2∗-weighted and diffusion-weighted functional magnetic resonance imaging (fMRI) approaches. MRI parameters were assessed in both groups of animals before, during and in a post-stimulus phase, following the administration of glucose or vehicle solutions. Hypothalamic nuclei depicted different patterns of activation characterized by: (i) generalized glucose-induced increases of neuronal activation and perfusion-markers in the lateral hypothalamus, arcuate and dorsomedial nuclei, (ii) cellular shrinking events and decreases in microvascular blood flow in the dorsomedial, ventromedial and lateral hypothalamus, following the administration of vehicle solutions and (iii) increased neuronal activity markers and decreased microperfusion parameters in the ARC nuclei of vehicle-administered animals. Immunohistochemical studies performed after the post-stimulus phase confirmed the presence of c-Fos immunoreactive neurons in the arcuate nucleus (ARC) from both animal groups, with significantly higher numbers in the glucose-treated animals. Together, our results reveal that fMRI methods are able to detect in vivo diverse patterns of glucose or vehicle-induced effects in the different hypothalamic nuclei., This work was supported in part by grants SAF-2014-53739-R, SAF2017-83043-R, and S2017/BMD-3688 to SC and PL-L, and grant BFU2014-52149-R and BFU2017-89336-R to MV.

© 2019 Gandía-González, Cerdán, Barrios, López-Larrubia, Feijoó, Palpan, Roda and Solivera., [Objective]: We assess the efficacy of the metabolomic profile from glioma biopsies in providing estimates of postsurgical Overall Survival in glioma patients., [Methods]: Tumor biopsies from 46 patients bearing gliomas, obtained neurosurgically in the period 1992–1998, were analyzed by high resolution 1H magnetic resonance spectroscopy (HR- 1H MRS), following retrospectively individual postsurgical Overall Survival up to 720 weeks., [Results]: The Overall Survival profile could be resolved in three groups; Short (shorter than 52 weeks, n = 19), Intermediate (between 53 and 364 weeks, n = 19) or Long (longer than 365 weeks, n = 8), respectively. Classical histopathological analysis assigned WHO grades II–IV to every biopsy but notably, some patients with low grade glioma depicted unexpectedly Short Overall Survival, while some patients with high grade glioma, presented unpredictably Long Overall Survival. To explore the reasons underlying these different responses, we analyzed HR-1H MRS spectra from acid extracts of the same biopsies, to characterize the metabolite patterns associated to OS predictions. Poor prognosis was found in biopsies with higher contents of alanine, acetate, glutamate, total choline, phosphorylcholine, and glycine, while more favorable prognosis was achieved in biopsies with larger contents of total creatine, glycerol-phosphorylcholine, and myo-inositol. We then implemented a multivariate analysis to identify hierarchically the influence of metabolomic biomarkers on OS predictions, using a Classification Regression Tree (CRT) approach. The CRT based in metabolomic biomarkers grew up to three branches and split into eight nodes, predicting correctly the outcome of 94.7% of the patients in the Short Overall Survival group, 78.9% of the patients in the Intermediate Overall Survival group, and 75% of the patients in the Long Overall Survival group, respectively., [Conclusion]: Present results indicate that metabolic profiling by HR-1H MRS improves the Overall Survival predictions derived exclusively from classical histopathological gradings, thus favoring more precise therapeutic decisions., This work was supported in part by grants PI2017/00361 from Instituto de Investigación Carlos III to JR, grant B2017/BMD-3688 from the Community of Madrid to JR and SC, and grant PI-0143-2016 from the Regional Ministry of Health of the Regional Government of Andalucía to JS.

© 2019 by the authors., Despite important advances in multimodal therapeutic options, glioblastoma (GBM), the most frequent and aggressive form of all astrocytomas, remains with a median overall survival period of 15 months. A direct correlation between GBM hypoxia and higher aggressiveness, poor prognosis and greater resistance to different treatments has been established. However, because of intratumoral and interindividual heterogeneity, it has not been possible to assess accurately the hypoxia degree from physiopathological parameters or neuroimaging methods. This study aims to develop and evaluate a magnetic resonance imaging (MRI) approach to identify more precisely those tumors that could improve the outcome through an oxygen targeted therapy. Methods: To assess the efficacy of radiotherapy in animals irradiated under air and oxygen breathing, we implemented a GBM animal model obtained by intracranial injection of glioma C6 cells in rats. MRI studies, based on the oxygen-induced contrast in blood (BOLD) and tissues (TOLD), were carried out to evaluate the effect of the modulation in oxygen breathing conditions on the tumors in vivo. The efficacy of the oxygen breathing therapies was determined by the relative tumor volume at the end of the experiment, compared to its size on the day before the treatment. Results: Our results categorized the tumors in responding, non-responding and intermediate behaviors. While BOLD analysis did not show any statistical difference between animals, either breathing air or oxygen, TOLD parameters allowed for the identification of the tumors with higher responses to hyperoxygenic radiotherapy. Conclusions: The non-invasive oxygen enhanced MRI acquisitions proposed here show promising potential to identify those tumors that would generally improve their response to a hypoxia targeted treatment., This work was supported by grants from the Ministry of Economy, Industry and Competitiveness (SAF2017-83043-R), and by the Program MULTITARGET&VIEW-CM from the Community of Madrid (S-BIO-0170-2006), involving contributions from FEDER and FSE funds.

The effects of long-term lead (Pb) exposure producing a blood Pb concentration of lower than 20 μg/dL, i.e. below that associated with overt neurological deficits in occupationally exposed individuals, was studied in adult rats. In order to assess gender differences, we performed parallel behavioral experiments in male and female rats. Exposure to Pb acetate (50 ppm in drinking water) for 6 months induced motor and cognitive alterations, however these effects were gender- and task-dependent. Chronic lead exposure impaired spatial learning assessed in the Morris water maze test (MWM) in both genders, whereas it only induced hyperactivity in the open field and impaired motor coordination in the rotarod test, only in male rats. Hyperactivity in male rats was accompanied by an increase in extracellular level of acetylcholine in the prefrontal cortex. Extracellular dopamine concentration in the prefrontal cortex was unaffected by lead exposure whereas serotonin concentration in the same brain area was significantly decreased in both male and female rats exposed to lead. These results unveil new molecular mechanisms underlying neuropsychiatric alterations induced by chronic lead exposure. © 2013 Published by Elsevier Ltd., This work was supported by a grant from the Ministerio de Ciencia e Innovación CTQ2010-20960-C02-02.

Development of neovasculature is a necessary requirement for tumour growth and it provides additional opportunities for therapeutic intervention. However, current antiangiogenic therapies have limited efficacy, mostly because of the development of resistance. Hence, characterization of new antiangiogenic molecular targets is of considerable clinical interest. We report that a calmodulin-binding domain (CaM-BD) deletion mutant of the growth factor receptor bound protein 7 (Grb7) (denoted Grb7Δ) impairs tumour growth and associated angiogenesis in vivo. We implanted glioma C6 cells in rat brains transfected with an enhanced yellow fluorescent protein (EYFP) chimera of Grb7∆, its EYFP-Grb7 wild type counterpart, and EYFP alone. We systematically followed intracerebral growth of the tumours, their cellularity and the functional performance of tumour-associated microvasculature using magnetic resonance imaging, including anatomical T1W and T2W images and functional diffusion and perfusion parameters. Tumours grown from implanted C6 cells expressing EYFP-Grb7Δ developed slower, became smaller and presented lower apparent cellularity than those derived from cells expressing EYFP-Grb7 and EYFP. Vascular perfusion measurements within tumours derived from EYFP-Grb7∆-expressing cells showed significantly lower cerebral blood flow (CBF), cerebral blood volume (CBV) and mean transit time (MTT) values. These findings were independently validated by histological and immunohistochemical techniques. Taken together, these findings confirm that the CaM-BD of Grb7 plays an important role in tumour growth and associated angiogenesis in vivo, thus identifying this region of the protein as a novel target for antiangiogenic treatment.

Type 2 diabetes mellitus has been associated with obesity, metabolic syndrome, cardiovascular diseases and cancer. Attempts have been made for early diagnosis and finding effective drugs to prevent severe consequences and ameliorate the symptoms of this disorder. In this work, the pharmacological properties of VO(dmpp) 2, [bis(1,2-dimethyl-3-hydroxy-4-pyridinonato) oxovanadium(IV)], were in vivo evaluated. For 4 weeks fatty Zucker rats were subjected to a daily dose of VO(dmpp) 2 (44 μmol/kg) and their metabolic profile was followed by assessing different biological parameters at established time points: body weight, subcutaneous fat width and hepatic triglyceride content determined by magnetic resonance imaging and spectroscopy, respectively. A glucose tolerance test was performed at the end of the experiment. After treatment, treated obese rats presented a weight significantly lower than the non-treated obese animals (359.0 ± 11.1 vs. 433.5 ± 6.2 g, P < 0.05), a thinner subcutaneous fat width, and a statistically significant decrease in hepatic triglyceride content (5.41 ± 0.59 vs. 21.03 ± 1.40%, P < 0.0005). Additionally, the glucose intolerant profile of fatty Zucker rats was completely reversed in treated animals (102.3 ± 2.1 vs. 172.4 ± 1.3 mg/100 mL; P < 0.0005). These results reinforce the therapeutic action of VO(dmpp) 2 which shows particular effects on lipid metabolism. © 2012 Elsevier Inc. All rights reserved., This work was supported by the grant CTQ2010-20960-C02-02 from Ministerio de Ciencia e Innovación, Spain, to Pilar López-Larrubia.

Hepatic triglyceride (HTG) accumulation from peripheral dietary sources and from endogenous de novo lipogenesis (DNL) was quantified in adult Sprague–Dawley rats by combining in vivo localized 1H MRS measurement of total hepatic lipid with a novel ex vivo2H NMR analysis of HTG 2H enrichment from 2H-enriched body water. The methodology for DNL determination needs further validation against standard methodologies. To examine the effect of a high-fat diet on HTG concentrations and sources, animals (n = 5) were given high-fat chow for 35 days. HTG accumulation, measured by in vivo1H MRS, increased significantly after 1 week (3.85 ± 0.60% vs 2.13 ± 0.34% for animals fed on a standard chow diet, P, Funded by: Portuguese Foundation for Science and Technology. Grant Numbers: SFRH/BD/17010/2005, POCTI/QUI/55603/2004 and Portuguese Foundation for Science and Technology/Luso-Espanhola Collaborative Actions. Grant Number: GRICES/CSIC 00620.

We evaluate the contribution of leptin-dependent anorexigenic pathways and neuropeptide Y (NPY)-dependent orexigenic pathways to the changes in hypothalamic water diffusion parameters observed in vivo by functional diffusion weighted MRI (fDWI). Mice genetically deficient in leptin (B6.V-Lep/J) or NPY (129S-Npy/J) and the corresponding wild-type controls, were subjected to sequential isocaloric feeding, fasting and recovery regimes. Non-invasive fDWI measurements were performed under these conditions, and complemented with parallel determinations of food and water consumption, respiratory exchange ratio (RER), locomotor activity and endocrine profiles. Control mice showed significant increases in hypothalamic water diffusion parameters upon fasting, returning to normal values in the recovery period. Leptin deficient mice depicted permanently increased water diffusion parameters under all feeding conditions as compared to wild type controls, without important changes upon fasting or recovery. These results paralleled sustained increases in food and water intake, significantly augmented body weight, and decreased RER values or locomotor activity, thus configuring an obese phenotype. NPY-deficient mice showed significantly reduced increases (or even slight decreases) in the water diffusion parameters upon fasting as compared to wild type controls, paralleled by decreased food and water intake during the recovery period. In conclusion, leptin deficiency results in sustained orexigenic stimulation, leading to increased water diffusion parameters, while NPY deficiency lead to reduced orexigenic stimulation and water diffusion parameters. Diffusion changes are proposed to reflect net astrocytic volume changes induced by the balance between the orexigenic and anorexigenic firings of AgRP/NPY and POMC/CART neurons, respectively. Together, our results suggest that fDWI provides an adequate tool to investigate hypothalamic appetite disorders., This work was supported in part by Grants SAF-2008-01327, SAF2011-23622 and IPT-2012-1331-006000 to SC, Grant CTQ-2010-20960-C02-02 to PLL, Grants S-BIO-2006-0170 and S2010/BMD-2349 to S.C. and PLL. BL held a predoctoral fellowship from the Spanish Ministry of Science and Technology (BES 2009-027615).

This is an Open Access article distributed under the terms of the Creative Commons Attribution License., [Background]: Glioblastoma, the most frequent and aggressive of all astrocytomas, presents a clear predominance in male humans, but the assessment of sexual differences in its tumourigenesis and growth has received little attention so far. In this study, we aim to identify gender-dependent surrogate markers in an animal model of this cancer by means of magnetic resonance (MR) imaging and biochemical and behavioural studies., [Methods]: A high-grade glioma model developed in male and female rats was used. Multiparametric magnetic resonance images and localized spectra were acquired. The MR parameters linked to tumoural features were quantified. Motor and metabolic activity was also assessed. Postmortem analyses were carried out to measure indicators of malignancy, tumoural metabolism and viability of the blood-brain barrier (BBB)., [Results]: Statistically significant differences dependent on the animal sex were found in the study of pathological indicators like oedema, inflammation, cellularity and microvasculature. Results suggest higher cell proliferative rate, inflammation and vasogenic oedema and or necrosis in glioma-bearing male rats. Haemodynamic parameters measured indicated a major disruption of the BBB, postmortem confirmed, in this sex. Metabolomic and energetic metabolism activity data are in agreement with a major malignancy and aggressiveness of this cancer model on males., [Conclusions]: Gender differences should be taken into account in preclinical studies of glioblastoma models, in the characterization of the tumoural behaviour and consequently in the development and validation of new therapeutic approaches. MR imaging and spectroscopy allow to non-invasively monitor this sexual dimorphism in the diagnosis and prognosis of brain cancer., This work was supported by grants from Ministerio de Ciencia e Innovación (CTQ2010-20960-C02-02) and Comunidad de Madrid (S-BIO-0170-2006)., We acknowledge the support of the publication fee by the CSIC Open Access Publication Support Initiative through its Unit of Information Resources for Research (URICI).

et al., [Background & Aims]: Low-grade cytotoxic oedema is considered a main contributor to the neurological (motor and cognitive) alterations in patients with hepatic encephalopathy (HE). This assumption is mainly based on studies with cultured astrocytes treated with very large ammonia concentrations or with animal models of acute liver failure with strong HE. However, the possible contribution of cerebral oedema (vasogenic or cytotoxic) to cognitive or motor alterations in chronic mild HE has not been demonstrated. The aim of this work was to assess whether cerebral oedema contributes to cognitive and/or motor alterations in rats with chronic mild HE. [Methods]: Motor activity and coordination and different types of learning and memory were assessed in rats with porta-caval shunts (PCS). Brain oedema was assessed by gravimetry in cerebellum and cortex and apparent diffusion coefficient (ADC) by magnetic resonance in 16 areas. [Results]: Four weeks after surgery, PCS rats show reduced motor activity and coordination, impaired ability to learn a conditional discrimination task in the Y maze and reduced spatial memory in the Morris water maze. PCS rats did not show increased brain water content at 4 or 10 weeks or changes in ADC at 4 weeks. At 10 weeks, increased ADC in some areas is compatible with vasogenic but not cytotoxic oedema. [Conclusion]: Cerebral oedema is not involved in motor and cognitive alterations in rats (and likely in humans) with mild HE. Proper understanding of the mechanisms responsible for the neurological alterations in HE is necessary to design efficient treatments. © 2013 John Wiley & Sons A/S., Financial support: Supported by grants from Ministerio Ciencia Innovación Spain (SAF2011-23051; CSD2008-00005), Consellería Educación (PROMETEO-2009-027; ACOMP/2011/053; ACOMP/2012/066) and Sanitat (AP-004/11) Generalitat Valenciana.

et al., Treatment of patients with acute liver failure (ALF) is unsatisfactory and mortality remains unacceptably high. Blocking NMDA receptors delays or prevents death of rats with ALF. The underlying mechanisms remain unclear. Clarifying these mechanisms will help to design more efficient treatments to increase patient's survival. The aim of this work was to shed light on the mechanisms by which blocking NMDA receptors delays rat's death in ALF. ALF was induced by galactosamine injection. NMDA receptors were blocked by continuous MK-801 administration. Edema and cerebral blood flow were assessed by magnetic resonance. The time course of ammonia levels in brain, muscle, blood, and urine; of glutamine, lactate, and water content in brain; of glomerular filtration rate and kidney damage; and of hepatic encephalopathy (HE) and intracranial pressure was assessed. ALF reduces kidney glomerular filtration rate (GFR) as reflected by reduced inulin clearance. GFR reduction is due to both reduced renal perfusion and kidney tubular damage as reflected by increased Kim-1 in urine and histological analysis. Blocking NMDA receptors delays kidney damage, allowing transient increased GFR and ammonia elimination which delays hyperammonemia and associated changes in brain. Blocking NMDA receptors does not prevent cerebral edema or blood-brain barrier permeability but reduces or prevents changes in cerebral blood flow and brain lactate. The data show that dual protective effects of MK-801 in kidney and brain delay cerebral alterations, HE, intracranial pressure increase and death. NMDA receptors antagonists may increase survival of patients with ALF by providing additional time for liver transplantation or regeneration. © 2013 Springer Science+Business Media New York., Supported by grants from Ministerio de Ciencia Innovacion Spain (SAF2008-00062, SAF2011-23051; CSD2008-00005; PS09/00806; PI10/01434) and Consellería Educación (PROMETEO-2009-027; ACOMP/2011/053; ACOMP/2012/066) and Conselleria Sanitat (AP-043-10, AP-004/11, AP-087/11) Generalitat Valenciana.

This is an open-access article distributed under the terms of the Creative Commons Attribution License., We review the role of neuroglial compartmentation and transcellular neurotransmitter cycling during hypothalamic appetite regulation as detected by Magnetic Resonance Imaging (MRI) and Spectroscopy (MRS) methods. We address first the neurochemical basis of neuroendocrine regulation in the hypothalamus and the orexigenic and anorexigenic feed-back loops that control appetite. Then we examine the main MRI and MRS strategies that have been used to investigate appetite regulation. Manganese-enhanced magnetic resonance imaging (MEMRI), Blood oxygenation level-dependent contrast (BOLD), and Diffusion-weighted magnetic resonance imaging (DWI) have revealed Mn(2+) accumulations, augmented oxygen consumptions, and astrocytic swelling in the hypothalamus under fasting conditions, respectively. High field (1)H magnetic resonance in vivo, showed increased hypothalamic myo-inositol concentrations as compared to other cerebral structures. (1)H and (13)C high resolution magic angle spinning (HRMAS) revealed increased neuroglial oxidative and glycolytic metabolism, as well as increased hypothalamic glutamatergic and GABAergic neurotransmissions under orexigenic stimulation. We propose here an integrative interpretation of all these findings suggesting that the neuroendocrine regulation of appetite is supported by important ionic and metabolic transcellular fluxes which begin at the tripartite orexigenic clefts and become extended spatially in the hypothalamus through astrocytic networks becoming eventually MRI and MRS detectable., This work was supported in part by grants SAF-2008-01327 and SAF2011-23622 to Sebastián Cerdán, grant CTQ-2010-20960-C02-02 to Pilar López, grants S-BIO-2006-0170 and S2010/BMD-2349 to Sebastián Cerdán, Pilar López-Larrubia, and Manuel Sánchez-Montañés. Blanca Lizarbe and Ania Benitez held predoctoral fellowships from the Spanish Ministry of Science and Technology (BES2009-027615) and the Spanish Agency for International Cooperation and Development.

This is an Open Access article distributed under the terms of the Creative Commons Attribution License.-- et al., [Background]: Mesenchymal stem cells (MSCs) have been promoted as an attractive option to use as cellular delivery vehicles to carry anti-tumor agents, owing to their ability to home into tumor sites and secrete cytokines. Multiple isolated populations have been described as MSCs, but despite extensive in vitro characterization, little is known about their in vivo behavior.The aim of this study was to investigate the efficacy and efficiency of different MSC lineages derived from five different sources (bone marrow, adipose tissue, epithelial endometrium, stroma endometrium, and amniotic membrane), in order to assess their adequacy for cell-based anti-tumor therapies. Our study shows the crucial importance of understanding the interaction between MSCs and tumor cells, and provides both information and a methodological approach, which could be used to develop safer and more accurate targeted therapeutic applications. [Methods]: We first measured the in vivo migration capacity and effect on tumor growth of the different MSCs using two imaging techniques: (i) single-photon emission computed tomography combined with computed tomography (SPECT-CT), using the human sodium iodine symporter gene (hNIS) and (ii) magnetic resonance imaging using superparamagnetic iron oxide. We then sought correlations between these parameters and expression of pluripotency-related or migration-related genes. [Results]: Our results show that migration of human bone marrow-derived MSCs was significantly reduced and slower than that obtained with the other MSCs assayed and also with human induced pluripotent stem cells (hiPSCs). The qPCR data clearly show that MSCs and hiPSCs exert a very different pluripotency pattern, which correlates with the differences observed in their engraftment capacity and with their effects on tumor growth. [Conclusion]: This study reveals differences in MSC recruitment/migration toward the tumor site and the corresponding effects on tumor growth. Three observations stand out: 1) tracking of the stem cell is essential to check the safety and efficacy of cell therapies; 2) the MSC lineage to be used in the cell therapy needs to be carefully chosen to balance efficacy and safety for a particular tumor type; and 3) different pluripotency and mobility patterns can be linked to the engraftment capacity of the MSCs, and should be checked as part of the clinical characterization of the lineage., This work was supported by FIS (PI080750), DGA (PI041/08, B84, PI086/09), MMA Fund (ICS/08/0050), PROMETEO/2008/163; CTQ-2010-20960-C02-02; S2010/BMD-2349, PIPAMER-0912, and PIPAMER-1214. CB-L was funded by fellowships ICS/08/0050 and DGA PI-086/09, GM by PIPAMER-0912, and PMD by the Araid Fund.

We investigated the behavioural effects of short-term lead (Pb) exposure in adult rats producing blood Pb concentration (, This work was supported by the grant from the Ministerio de Ciencia e Innovación CTQ2010-20960-C02-02.

Diffusion-weighted imaging (DWI) allows the assessment of the water apparent diffusion coefficient (ADC), a measure of tissue water diffusivity which is altered during different pathological conditions such as cerebral oedema. By means of DWI, we repeatedly measured in the same rats apparent diffusion coefficient ADC in different brain areas (motor cortex (MCx), somato-sensory cortex (SCx), caudate-putamen (CPu), hippocampus (Hip), mesencephalic reticular formation (RF), corpus callosum (CC) and cerebellum (Cb)) after 1 week, 4 and 12 weeks of lead acetate exposure via drinking water (50 or 500ppm). After 12 weeks of lead exposure rats received albumin-Evans blue complex administration and were sacrified 1h later. Blood-brain barrier permeability and water tissue content were determined in order to evaluate their relationship with ADC changes. Chronic exposure to lead acetate (500ppm) for 4 weeks increased ADC values in Hip, RF and Cb but no in other brain areas. After 12 weeks of lead acetate exposure at 500ppm ADC is significantly increased also in CPu and CC. Brain areas displaying high ADC values after lead exposure showed also an increased water content and increased BBB permeability to Evans blue-albumin complex. Exposure to 50ppm for 12 weeks increased ADC values and BBB permeability in the RF and Cb. In summary, chronic lead exposure induces cerebral oedema in the adult brain depending on the brain area and the dose of exposure. RF and Cb appeared the most sensitive brain areas whereas cerebral cortex appears resistant to lead-induced cerebral oedema., This work was supported by the grant from the Ministerio de Ciencia y Innovación CTQ2009-14146-C02-02.

Experimental models of traumatic brain injury (TBI) provide a useful tool for understanding the cerebral metabolic changes induced by this pathological condition. Here, we report on the time course of changes in cerebral metabolites after TBI and its correlation with early brain morphological changes using a combination of high-resolution proton magnetic resonance spectroscopy ( 1H MRS) and magnetic resonance imaging (MRI). Adult male Sprague-Dawley rats were subjected to closed head impact and examined by MRI at 1, 9, 24, 48, and and 72 h after the injury. Extracts from funnel frozen rat brains were then obtained and analyzed quantitatively by high-resolution 1H MRS. Finally, statistical multivariate analysis was carried out to identify the combination of cerebral metabolites that best described the time evolution of diffuse TBI. The temporal changes observed in the concentration of cerebral metabolites followed three different patterns. The first pattern included taurine, threonine, and glycine, with concentrations peaking 24 h after the injury. The second pattern included glutamate, GABA, and alanine, with concentrations remaining elevated between 24 and 48 h post-injury. The third one involved creatine-phosphocreatine, N-acetylaspartate, and myo-inositol, with concentrations peaking 48 h after the injury. A multivariate stepwise discriminant analysis revealed that the combination of the organic osmolytes taurine and myo-inositol allowed optimal discrimination among the different time groups. Our findings suggest that the profile of some specific brain molecules that play a role as organic osmolytes can be used to follow-up the progression of the early diffuse brain edema response induced by TBI. © Mary Ann Liebert, Inc., This work was partly supported by Spanish Ministry of Education and Science (grants SAF 2001-224 and SAF 2004-03197 to J.M.R. and S.C.) and by Spanish Ministry of Health (grants FISss C03/08, C03/10, and G03/155 to J.M.R. and S.C.).

Acute ammonia intoxication leads to rapid death, which is prevented by blocking N-methyl-d-aspartate (NMDA) receptors. The subsequent mechanisms leading to death remain unclear. Brain edema seems an important step. The aim of this work was to study the effects of acute ammonia intoxication on different cerebral parameters in vivo using magnetic resonance and to assess which effects are mediated by NMDA receptors activation. To assess edema induction, we injected rats with ammonium acetate and measured apparent diffusion coefficient (ADC) in 16 brain areas. We also analyzed the effects on T1, T2, and T2* maps and whether these effects are prevented by blocking NMDA receptors. The effects of acute ammonia intoxication are different in different brain areas. T1 relaxation time is reduced in eight areas. T2 relaxation time is reduced only in ventral thalamus and globus pallidus. ADC values increased in hippocampus, caudate-putamen, substantia nigra and cerebellar cortex, reflecting vasogenic edema. ADC decreased in hypothalamus, reflecting cytotoxic edema. Myo-inositol increased in cerebellum and substantia nigra, reflecting vasogenic edema. N-acetyl-aspartate decreased in cerebellum, reflecting neuronal damage. Changes in N-acetyl-aspartate, T1 and T2 are prevented by blocking NMDA receptors with MK-801 while changes in ADC or myo-inositol (induction of edema) are not. © 2007 The Authors., This work was supported by grants from Ministerio de Educación y Ciencia (SAF2004-0001-E and SAF2005-06089) and from Ministerio de Sanidad (Red G03-155 and FIS PI050253) of Spain and by grants from Consellería de Empresa, Universidad y Ciencia (Grupos03/001, GV04B-012, GVS05/082, ACOMP06/005; ACOMP/2007/002) and AP005/06 from Conselleria de Sanitat of Generalitat Valenciana. T.B. Rodrigues was supported by fellowship from Fundacao para a Ciencia e tecnologia/Ministerio da Ciencia e Ensino Superior-Portugal (SFRH/BD/5407/2001).