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Glutamate Uptake Is Not Impaired by Hypoxia in a Culture Model of Human Fetal Neural Stem Cell-Derived Astrocytes. Genes (Basel) 2022; 13:genes13030506. [PMID: 35328060 PMCID: PMC8953426 DOI: 10.3390/genes13030506] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2022] [Revised: 03/04/2022] [Accepted: 03/09/2022] [Indexed: 02/04/2023] Open
Abstract
Hypoxic ischemic injury to the fetal and neonatal brain is a leading cause of death and disability worldwide. Although animal and culture studies suggest that glutamate excitotoxicity is a primary contributor to neuronal death following hypoxia, the molecular mechanisms, and roles of various neural cells in the development of glutamate excitotoxicity in humans, is not fully understood. In this study, we developed a culture model of human fetal neural stem cell (FNSC)-derived astrocytes and examined their glutamate uptake in response to hypoxia. We isolated, established, and characterized cultures of FNSCs from aborted fetal brains and differentiated them into astrocytes, characterized by increased expression of the astrocyte markers glial fibrillary acidic protein (GFAP), excitatory amino acid transporter 1 (EAAT1) and EAAT2, and decreased expression of neural stem cell marker Nestin. Differentiated astrocytes were exposed to various oxygen concentrations mimicking normoxia (20% and 6%), moderate and severe hypoxia (2% and 0.2%, respectively). Interestingly, no change was observed in the expression of the glutamate transporter EAAT2 or glutamate uptake by astrocytes, even after exposure to severe hypoxia for 48 h. These results together suggest that human FNSC-derived astrocytes can maintain glutamate uptake after hypoxic injury and thus provide evidence for the possible neuroprotective role of astrocytes in hypoxic conditions.
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Fiskum V, Sandvig A, Sandvig I. Silencing of Activity During Hypoxia Improves Functional Outcomes in Motor Neuron Networks in vitro. Front Integr Neurosci 2021; 15:792863. [PMID: 34975426 PMCID: PMC8716921 DOI: 10.3389/fnint.2021.792863] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2021] [Accepted: 12/01/2021] [Indexed: 11/13/2022] Open
Abstract
The effects of hypoxia, or reduced oxygen supply, to brain tissue can be disastrous, leading to extensive loss of function. Deoxygenated tissue becomes unable to maintain healthy metabolism, which leads to increased production of reactive oxygen species (ROS) and loss of calcium homoeostasis, with damaging downstream effects. Neurons are a highly energy demanding cell type, and as such they are highly sensitive to reductions in oxygenation and some types of neurons such as motor neurons are even more susceptible to hypoxic damage. In addition to the immediate deleterious effects hypoxia can have on neurons, there can be delayed effects which lead to increased risk of developing neurodegenerative diseases such as amyotrophic lateral sclerosis (ALS), even if no immediate consequences are apparent. Furthermore, impairment of the function of various hypoxia-responsive factors has been shown to increase the risk of developing several neurodegenerative disorders. Longitudinal assessment of electrophysiological network activity is underutilised in assessing the effects of hypoxia on neurons and how their activity and communication change over time following a hypoxic challenge. This study utilised multielectrode arrays and motor neuron networks to study the response to hypoxia and the subsequent development of the neuronal activity over time, as well as the effect of silencing network activity during the hypoxic challenge. We found that motor neuron networks exposed to hypoxic challenge exhibited a delayed fluctuation in multiple network activity parameters compared to normoxic networks. Silencing of activity during the hypoxic challenge leads to maintained bursting activity, suggesting that functional outcomes are better maintained in these networks and that there are activity-dependent mechanisms involved in the network damage following hypoxia.
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Affiliation(s)
- Vegard Fiskum
- Department of Neuromedicine and Movement Science, Faculty of Medicine and Health Sciences, Norwegian University of Science and Technology, Trondheim, Norway
| | - Axel Sandvig
- Department of Neuromedicine and Movement Science, Faculty of Medicine and Health Sciences, Norwegian University of Science and Technology, Trondheim, Norway
- Department of Neurology, St. Olav’s Hospital, Trondheim University Hospital, Trondheim, Norway
- Department of Pharmacology and Clinical Neurosciences, Division of Neuro, Head, and Neck, Umeå University Hospital, Umeå, Sweden
- Department of Community Medicine and Rehabilitation, Umeå University, Umeå, Sweden
| | - Ioanna Sandvig
- Department of Neuromedicine and Movement Science, Faculty of Medicine and Health Sciences, Norwegian University of Science and Technology, Trondheim, Norway
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3
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Bheemanapally K, Ibrahim MMH, Briski KP. HPLC-electrospray ionization-mass spectrometry optimization by high-performance design of experiments for astrocyte glutamine measurement. JOURNAL OF MASS SPECTROMETRY : JMS 2021; 56:e4680. [PMID: 33462970 PMCID: PMC7874509 DOI: 10.1002/jms.4680] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/02/2020] [Revised: 11/01/2020] [Accepted: 11/04/2020] [Indexed: 06/12/2023]
Abstract
The amino acid glutamine (Gln) is a likely source of energy in the brain during neuroglucopenia. Effects of glucose deficiency on astrocyte Gln homeostasis remain unclear, as analytical tools of requisite sensitivity for quantification of intracellular levels of this molecule are not currently available. Here, a primary hypothalamic astrocyte culture model was used in conjunction with design of experiments (DOE)-refined high-performance liquid chromatography-electrospray ionization-mass spectrometry (LC-ESI-MS) methodology to investigate the hypothesis that glucoprivation alters astrocyte Gln content in a sex-specific manner. Critical mass spectrometric parameters for Gln derivative chromatographic response were identified by comparing the performance of central composite design, Box-Behnken design, and Optimal Design (OD)-A, -D, -I, -Distance, and -Modified Distance DOE models. The outcomes showed that the OD-A-generated response was superior relative to other design outcomes. Forecasted surface plot critical mass spectrometric parameters were maximized by OD-A, OD-Distance, and OD-Modified Distance designs. OD-A produced a high-performance method that yielded experimental run and forecasted surface plot maximal responses. Optimized mass spectrometric analysis of male versus female astrocyte Gln content provides novel evidence that glucoprivation significantly depletes this amino acid in female, but not in male, and that this sex-specific response may involve differential sensitivity to estrogen receptor signaling. This technological advance will facilitate efforts to ascertain how distinctive physiological and pathophysiological stimuli impact astrocyte Gln metabolism in each sex.
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Affiliation(s)
- Khaggeswar Bheemanapally
- School of Basic Pharmaceutical and Toxicological Sciences, College of Pharmacy, University of Louisiana Monroe, Monroe, Louisiana, 71201, USA
| | - Mostafa M H Ibrahim
- School of Basic Pharmaceutical and Toxicological Sciences, College of Pharmacy, University of Louisiana Monroe, Monroe, Louisiana, 71201, USA
| | - Karen P Briski
- School of Basic Pharmaceutical and Toxicological Sciences, College of Pharmacy, University of Louisiana Monroe, Monroe, Louisiana, 71201, USA
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Stovell MG, Mada MO, Carpenter TA, Yan JL, Guilfoyle MR, Jalloh I, Welsh KE, Helmy A, Howe DJ, Grice P, Mason A, Giorgi-Coll S, Gallagher CN, Murphy MP, Menon DK, Hutchinson PJ, Carpenter KL. Phosphorus spectroscopy in acute TBI demonstrates metabolic changes that relate to outcome in the presence of normal structural MRI. J Cereb Blood Flow Metab 2020; 40:67-84. [PMID: 30226401 PMCID: PMC6927074 DOI: 10.1177/0271678x18799176] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Metabolic dysfunction is a key pathophysiological process in the acute phase of traumatic brain injury (TBI). Although changes in brain glucose metabolism and extracellular lactate/pyruvate ratio are well known, it was hitherto unknown whether these translate to downstream changes in ATP metabolism and intracellular pH. We have performed the first clinical voxel-based in vivo phosphorus magnetic resonance spectroscopy (31P MRS) in 13 acute-phase major TBI patients versus 10 healthy controls (HCs), at 3T, focusing on eight central 2.5 × 2.5 × 2.5 cm3 voxels per subject. PCr/γATP ratio (a measure of energy status) in TBI patients was significantly higher (median = 1.09) than that of HCs (median = 0.93) (p < 0.0001), due to changes in both PCr and ATP. There was no significant difference in PCr/γATP between TBI patients with favourable and unfavourable outcome. Cerebral intracellular pH of TBI patients was significantly higher (median = 7.04) than that of HCs (median = 7.00) (p = 0.04). Alkalosis was limited to patients with unfavourable outcome (median = 7.07) (p < 0.0001). These changes persisted after excluding voxels with > 5% radiologically visible injury. This is the first clinical demonstration of brain alkalosis and elevated PCr/γATP ratio acutely after major TBI. 31P MRS has potential for non-invasively assessing brain injury in the absence of structural injury, predicting outcome and monitoring therapy response.
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Affiliation(s)
- Matthew G Stovell
- Division of Neurosurgery, Department of Clinical Neurosciences, University of Cambridge, Cambridge, UK
| | - Marius O Mada
- Wolfson Brain Imaging Centre, Department of Clinical Neurosciences, University of Cambridge, Cambridge, UK
| | - T Adrian Carpenter
- Wolfson Brain Imaging Centre, Department of Clinical Neurosciences, University of Cambridge, Cambridge, UK
| | - Jiun-Lin Yan
- Division of Neurosurgery, Department of Clinical Neurosciences, University of Cambridge, Cambridge, UK.,Department of Neurosurgery, Keelung Chang Gung Memorial Hospital, Chang Gung University College of Medicine, Taoyuan, Taiwan
| | - Mathew R Guilfoyle
- Division of Neurosurgery, Department of Clinical Neurosciences, University of Cambridge, Cambridge, UK
| | - Ibrahim Jalloh
- Division of Neurosurgery, Department of Clinical Neurosciences, University of Cambridge, Cambridge, UK
| | - Karen E Welsh
- Wolfson Brain Imaging Centre, Department of Clinical Neurosciences, University of Cambridge, Cambridge, UK
| | - Adel Helmy
- Division of Neurosurgery, Department of Clinical Neurosciences, University of Cambridge, Cambridge, UK
| | - Duncan J Howe
- Department of Chemistry, University of Cambridge, Cambridge, UK
| | - Peter Grice
- Department of Chemistry, University of Cambridge, Cambridge, UK
| | - Andrew Mason
- Department of Chemistry, University of Cambridge, Cambridge, UK
| | - Susan Giorgi-Coll
- Division of Neurosurgery, Department of Clinical Neurosciences, University of Cambridge, Cambridge, UK
| | - Clare N Gallagher
- Division of Neurosurgery, Department of Clinical Neurosciences, University of Cambridge, Cambridge, UK.,Division of Neurosurgery, Department of Clinical Neurosciences, University of Calgary, Calgary, Alberta, Canada
| | - Michael P Murphy
- MRC Mitochondrial Biology Unit, University of Cambridge, Cambridge, UK
| | - David K Menon
- Wolfson Brain Imaging Centre, Department of Clinical Neurosciences, University of Cambridge, Cambridge, UK.,Division of Anaesthesia, Department of Medicine, University of Cambridge, Cambridge, UK
| | - Peter J Hutchinson
- Division of Neurosurgery, Department of Clinical Neurosciences, University of Cambridge, Cambridge, UK.,Wolfson Brain Imaging Centre, Department of Clinical Neurosciences, University of Cambridge, Cambridge, UK
| | - Keri Lh Carpenter
- Division of Neurosurgery, Department of Clinical Neurosciences, University of Cambridge, Cambridge, UK.,Wolfson Brain Imaging Centre, Department of Clinical Neurosciences, University of Cambridge, Cambridge, UK
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Intracellular Neuroprotective Mechanisms in Neuron-Glial Networks Mediated by Glial Cell Line-Derived Neurotrophic Factor. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2019; 2019:1036907. [PMID: 31827666 PMCID: PMC6885812 DOI: 10.1155/2019/1036907] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/15/2019] [Accepted: 10/19/2019] [Indexed: 12/28/2022]
Abstract
Glial cell line-derived neurotrophic factor (GDNF) has a pronounced neuroprotective effect in various nervous system pathologies, including ischaemic brain damage and neurodegenerative diseases. In this work, we studied the effect of GDNF on the ultrastructure and functional activity of neuron-glial networks during acute hypoxic exposure, a key damaging factor in numerous brain pathologies. We analysed the molecular mechanisms most likely involved in the positive effects of GDNF. Hypoxia modelling was performed on day 14 of culturing primary hippocampal cells obtained from mouse embryos (E18). GDNF (1 ng/ml) was added to the culture medium 20 min before oxygen deprivation. Acute hypoxia-induced irreversible changes in the ultrastructure of neurons and astrocytes led to the loss of functional Сa2+ activity and neural network disruption. Destructive changes in the mitochondrial apparatus and its functional activity characterized by an increase in the basal oxygen consumption rate and respiratory chain complex II activity during decreased stimulated respiration intensity were observed 24 hours after hypoxic injury. At a concentration of 1 ng/ml, GDNF maintained the functional metabolic network activity in primary hippocampal cultures and preserved the structure of the synaptic apparatus and number of mature chemical synapses, confirming its neuroprotective effect. GDNF maintained the normal structure of mitochondria in neuronal outgrowth but not in the soma. Analysis of the possible GDNF mechanism revealed that RET kinase, a component of the receptor complex, and the PI3K/Akt pathway are crucial for the neuroprotective effect of GDNF. The current study also revealed the role of GDNF in the regulation of HIF-1α transcription factor expression under hypoxic conditions.
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Yager JY. Glucose and Perinatal Brain Injury—Questions and Controversies. Neurology 2019. [DOI: 10.1016/b978-0-323-54392-7.00009-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
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8
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Downs DM, Bazurto JV, Gupta A, Fonseca LL, Voit EO. The three-legged stool of understanding metabolism: integrating metabolomics with biochemical genetics and computational modeling. AIMS Microbiol 2018; 4:289-303. [PMID: 31294216 PMCID: PMC6604926 DOI: 10.3934/microbiol.2018.2.289] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2018] [Accepted: 04/02/2018] [Indexed: 12/23/2022] Open
Abstract
Traditional biochemical research has resulted in a good understanding of many aspects of metabolism. However, this reductionist approach is time consuming and requires substantial resources, thus raising the question whether modern metabolomics and genomics should take over and replace the targeted experiments of old. We proffer that such a replacement is neither feasible not desirable and propose instead the tight integration of modern, system-wide omics with traditional experimental bench science and dedicated computational approaches. This integration is an important prerequisite toward the optimal acquisition of knowledge regarding metabolism and physiology in health and disease. The commentary describes advantages and drawbacks of current approaches to assessing metabolism and highlights the challenges to be overcome as we strive to achieve a deeper level of metabolic understanding in the future.
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Affiliation(s)
- Diana M Downs
- Department of Microbiology, University of Georgia, Athens, GA, 30602, USA
| | - Jannell V Bazurto
- Department of Biological Sciences, University of Idaho, Moscow, ID, 83844, USA
| | - Anuj Gupta
- Department of Biomedical Engineering, Georgia Institute of Technology, 950 Atlantic Drive, Suite 2115, Atlanta, GA, 30332-2000, USA
| | - Luis L Fonseca
- Department of Biomedical Engineering, Georgia Institute of Technology, 950 Atlantic Drive, Suite 2115, Atlanta, GA, 30332-2000, USA
| | - Eberhard O Voit
- Department of Biomedical Engineering, Georgia Institute of Technology, 950 Atlantic Drive, Suite 2115, Atlanta, GA, 30332-2000, USA
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9
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Abstract
Cell metabolism is a key determinant factor for the pluripotency and fate commitment of Stem Cells (SCs) during development, ageing, pathological onset and progression. We derived and cultured selected subpopulations of rodent fetal, postnatal, adult Neural SCs (NSCs) and postnatal glial progenitors, Olfactory Ensheathing Cells (OECs), respectively from the subventricular zone (SVZ) and the olfactory bulb (OB). Cell lysates were analyzed by proton Nuclear Magnetic Resonance (1H-NMR) spectroscopy leading to metabolites identification and quantitation. Subsequent multivariate analysis of NMR data by Principal Component Analysis (PCA), and Partial Least Square Discriminant Analysis (PLS-DA) allowed data reduction and cluster analysis. This strategy ensures the definition of specific features in the metabolic content of phenotypically similar SCs sharing a common developmental origin. The metabolic fingerprints for selective metabolites or for the whole spectra demonstrated enhanced peculiarities among cell types. The key result of our work is a neat divergence between OECs and the remaining NSC cells. We also show that statistically significant differences for selective metabolites characterizes NSCs of different ages. Finally, the retrived metabolome in cell cultures correlates to the physiological SC features, thus allowing an integrated bioengineering approach for biologic fingerprints able to dissect the (neural) SC molecular specificities.
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10
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Marina N, Kasymov V, Ackland GL, Kasparov S, Gourine AV. Astrocytes and Brain Hypoxia. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2016; 903:201-7. [PMID: 27343098 DOI: 10.1007/978-1-4899-7678-9_14] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Astrocytes provide the structural and functional interface between the cerebral circulation and neuronal networks. They enwrap all intracerebral arterioles and capillaries, control the flux of nutrients as well as the ionic and metabolic environment of the neuropil. Astrocytes have the ability to adjust cerebral blood flow to maintain constant PO2 and PCO2 of the brain parenchyma. Release of ATP in the brainstem, presumably by local astrocytes, helps to maintain breathing and counteract hypoxia-induced depression of the respiratory network. Astrocytes also appear to be involved in mediating hypoxia-evoked changes in blood-brain barrier permeability, brain inflammation, and neuroprotection against ischaemic injury. Thus, astrocytes appear to play a fundamental role in supporting neuronal function not only in normal conditions but also in pathophysiological states when supply of oxygen to the brain is compromised.
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Affiliation(s)
- Nephtali Marina
- Neuroscience, Physiology & Pharmacology, University College London, London, UK
| | - Vitaliy Kasymov
- Neuroscience, Physiology & Pharmacology, University College London, London, UK
| | - Gareth L Ackland
- Experimental Medicine, Wolfson Institute for Biomedical Research, University College London, London, UK
| | - Sergey Kasparov
- Department of Physiology and Pharmacology, University of Bristol, Bristol, UK
| | - Alexander V Gourine
- Neuroscience, Physiology & Pharmacology, University College London, London, UK.
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11
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Duarte TM, Carinhas N, Silva AC, Alves PM, Teixeira AP. ¹H-NMR protocol for exometabolome analysis of cultured mammalian cells. Methods Mol Biol 2014; 1104:237-247. [PMID: 24297420 DOI: 10.1007/978-1-62703-733-4_16] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
(1)H-Nuclear magnetic resonance ((1)H-NMR) spectroscopy is a powerful technique to analyze the composition of complex mixtures based on the particular proton fingerprint of each molecule. Here we describe a protocol for exometabolome analysis of mammalian cells using this technique, including sample preparation, spectra acquisition, and integration. The potential of this technique is exemplified by application to cultures of a Chinese hamster ovary (CHO) cell line. The average error associated to this method is under 3% and the limit of quantification for all metabolites analyzed is below 180 μM.
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Affiliation(s)
- Tiago M Duarte
- Instituto de Tecnologia Química e Biológica, Universidade Nova de Lisboa, Oeiras, Portugal
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12
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Characterisation of endothelin-1-induced intrastriatal lesions within the juvenile and adult rat brain using MRI and 31P MRS. Transl Stroke Res 2013; 4:351-67. [PMID: 24323302 DOI: 10.1007/s12975-013-0258-1] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2012] [Revised: 03/11/2013] [Accepted: 03/18/2013] [Indexed: 01/12/2023]
Abstract
Improved non-invasive magnetic resonance (MR) characterisation of in vivo models of focal ischaemic insults such as transient ischaemic attack (TIA) and perinatal arterial ischaemic stroke (AIS) may assist diagnosis, outcome prediction and treatment design. The classic middle cerebral artery occlusion (MCAO) model of ischaemic stroke is well documented in MR studies but generates extensive and complex lesions involving an acute inflammatory response and de-occlusion that immediately restores circulation. By contrast, intrastriatal microinjection of the potent vasoconstrictor, endothelin-1 (ET-1), induces a focal, reversible and low-flow ischaemia in the absence of a typical inflammatory response, which gradually restores blood flow over several hours and may be more relevant to TIA and AIS pathology. This study presents the first comprehensive longitudinal MR characterisation of the real-time anatomical [T1-weighted (T1-w)/T2-weighted (T2-w)], pathophysiological [apparent diffusion coefficient (ADC), cerebral blood volume, gadolinium contrast imaging of blood-brain barrier (BBB) integrity] and metabolic [phosphorus magnetic resonance spectroscopy (31P MRS)] evolution of a purely ischaemic ET-1-induced lesion within the juvenile and adult rat brain. ET-1-induced cytotoxic oedema was visualised on T2-w magnetic resonance imaging (MRI), inconsistent with the conventional notion that it cannot be detected using anatomical MRI. There was no immunohistochemical evidence of an acute inflammatory response or loss of BBB integrity, thus excluding a vasogenic oedema contribution to the pathology. Maximal T2-w intensity correlated with the lowest ADC value in both age groups, re-emphasising the purely ischaemic nature of the lesion and the absence of vasogenic oedema. Furthermore, extensive acute T1-w hypointensity was observed in the presence of cytotoxic oedema-induced T2-w changes, whereas other authors have shown that increased T1 values following MCAO reflect vasogenic oedema. Intriguingly, the lesion border exhibited hyperintensity on T2-w and ADC MRI at later time points, and the former may be a consequence of phagocytosis-induced fatty droplet deposition by macrophages detected immunohistochemically. In spite of a chronically reduced ADC, typically associated with ischaemia-induced energy failure, a 31P MRS-detectable reduction in the phosphocreatine (PCr) to gamma adenosine triphosphate (γATP) ratio was not observed at any time point in either age group, suggesting dissociation of tissue water diffusion and metabolic changes within the ET-1-induced lesion.
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Saggu R, Morrison B, Lowe JP, Pringle AK. Interleukin-1beta does not affect the energy metabolism of rat organotypic hippocampal-slice cultures. Neurosci Lett 2011; 508:114-8. [PMID: 22215116 DOI: 10.1016/j.neulet.2011.12.032] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2011] [Revised: 12/16/2011] [Accepted: 12/19/2011] [Indexed: 11/28/2022]
Abstract
The aim of this study was to examine the effect of the archetypal pro-inflammatory cytokine, interleukin-1beta (IL-1β), on high-energy phosphate levels within an ex vivo rat organotypic hippocampal-slice culture (OHSC) preparation using phosphorus ((31)P) magnetic resonance spectroscopy (MRS). Intrastriatal microinjection of IL-1β induces a chronic reduction in the apparent diffusion coefficient (ADC) of tissue water, which may be indicative of metabolic failure as established by in vivo models of acute cerebral ischaemia. The OHSC preparation enables examination of the effects of IL-1β on brain parenchyma per se, independent of the potentially confounding effects encountered in vivo such as perfusion changes, blood-brain barrier (BBB) breakdown and leukocyte recruitment. (31)P MRS is a technique that can detect multiple high-energy phosphate metabolites within a sample non-invasively. Here, for the first time, we characterise the energy metabolism of OHSCs using (31)P MRS and demonstrate that IL-1β does not compromise high-energy phosphate metabolism. Thus, the chronic reduction in ADC observed in vivo is unlikely to be a consequence of metabolic failure.
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Affiliation(s)
- Raman Saggu
- Department of Biochemistry, South Parks Road, University of Oxford, South Parks Road, OX1 3QU, UK.
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14
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Amaral AI, Teixeira AP, Martens S, Bernal V, Sousa MFQ, Alves PM. Metabolic alterations induced by ischemia in primary cultures of astrocytes: merging 13C NMR spectroscopy and metabolic flux analysis. J Neurochem 2010; 113:735-48. [PMID: 20141568 DOI: 10.1111/j.1471-4159.2010.06636.x] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Disruption of brain energy metabolism is the hallmark of cerebral ischemia, a major cause of death worldwide. Astrocytes play a key role in the regulation of brain metabolism and their vulnerability to ischemia has been described. Aiming to quantify the effects of an ischemic insult in astrocytic metabolism, primary cultures of astrocytes were subjected to 5 h of oxygen and glucose deprivation in a bioreactor. Flux distributions, before and after ischemia, were estimated by metabolic flux analysis using isotopic information and the consumption/secretion rates of relevant extracellular metabolites as constraints. During ischemia and early recovery, 30% of cell death was observed; several metabolic alterations were also identified reflecting a metabolic response by the surviving cells. In the early recovery ( approximately 10 h), astrocytes up-regulated glucose utilization by 30% and increased the pentose phosphate pathway and tricarboxylic acid cycle fluxes by three and twofold, respectively. Additionally, a two to fivefold enhancement in branched-chain amino acids catabolism suggested the importance of anaplerotic molecules to the fast recovery of the energetic state, which was corroborated by measured cellular ATP levels. Glycolytic metabolism was predominant in the late recovery. In summary, this work demonstrates that changes in fluxes of key metabolic pathways are implicated in the recovery from ischemia in astrocytes.
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Affiliation(s)
- Ana I Amaral
- Instituto de Tecnologia Química e Biológica - Universidade Nova de Lisboa, and Instituto de Biologia Experimental e Tecnológica, Oeiras, Portugal
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15
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Tsai S, Rawson DM, Zhang T. Development of cryopreservation protocols for early stage zebrafish (Danio rerio) ovarian follicles using controlled slow cooling. Theriogenology 2009; 71:1226-33. [PMID: 19250661 DOI: 10.1016/j.theriogenology.2009.01.014] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2008] [Revised: 01/21/2009] [Accepted: 01/25/2009] [Indexed: 10/21/2022]
Abstract
Cryopreservation of germplasm of aquatic species offers many benefits to the fields of aquaculture, conservation and biomedicine. Although successful fish sperm cryopreservation has been achieved with many species, there has been no report of successful cryopreservation of fish embryos and late stage oocytes which are large, chilling sensitive and have low membrane permeability. In the present study, cryopreservation of early stage zebrafish ovarian follicles was studied for the first time using controlled slow freezing. The effect of cryoprotectant, freezing medium, cooling rate, method for cryoprotectant removal, post-thaw incubation time and ovarian follicle developmental stage were investigated. Stages I and II ovarian follicles were frozen in 4M methanol and 3M DMSO in either L-15 medium or KCl buffer. Ovarian follicle viability was assessed using trypan blue, FDA+PI staining and ADP/ATP assay. The results showed that KCl buffer was more beneficial than L-15 medium, methanol was more effective than DMSO, optimum cooling rates were 2-4 degrees C/min, stepwise removal of cryoprotectant improved ovarian follicle viability significantly and stage I ovarian follicles were more sensitive to freezing. The results also showed that FDA+PI staining and ADP/ATP assay were more sensitive than TB staining. The highest follicle viabilities after post-thaw incubation for 2h obtained with FDA+PI staining were 50.7+/-4.0% although ADP/ATP ratios of the cryopreserved follicles were significantly increased indicating increased cell damage. Studies are currently being carried out on in vitro maturation of these cryopreserved ovarian follicles.
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Affiliation(s)
- S Tsai
- LIRANS Institute of Research in the Applied Natural Sciences, University of Bedfordshire, Luton, UK
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Malthankar-Phatak GH, Patel AB, Xia Y, Hong S, Chowdhury GMI, Behar KL, Orina IA, Lai JCK. Effects of continuous hypoxia on energy metabolism in cultured cerebro-cortical neurons. Brain Res 2008; 1229:147-54. [PMID: 18621040 DOI: 10.1016/j.brainres.2008.06.074] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2008] [Revised: 06/19/2008] [Accepted: 06/23/2008] [Indexed: 12/18/2022]
Abstract
Mechanisms underlying hypoxia-induced neuronal adaptation have not been fully elucidated. In the present study we investigated glucose metabolism and the activities of glycolytic and TCA cycle enzymes in cerebro-cortical neurons exposed to hypoxia (3 days in 1% of O2) or normoxia (room air). Hypoxia led to increased activities of LDH (194%), PK (90%), and HK (24%) and decreased activities of CS (15%) and GDH (34%). Neurons were incubated with [1-(13)C]glucose for 45 and 120 min under normoxic or hypoxic (120 min only) conditions and 13C enrichment determined in the medium and cell extract using 1H-{13C}-NMR. In hypoxia-treated neurons [3-(13)C]lactate release into the medium was 428% greater than in normoxia-treated controls (45-min normoxic incubation) and total flux through lactate was increased by 425%. In contrast glucose oxidation was reduced significantly in hypoxia-treated neurons, even when expressed relative to total cellular protein, which correlated with the reduced activities of the measured mitochondrial enzymes. The results suggest that surviving neurons adapt to prolonged hypoxia by up-regulation of glycolysis and down-regulation of oxidative energy metabolism, similar to certain other cell types. The factors leading to adaptation and survival for some neurons but not others remain to be determined.
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Affiliation(s)
- Gauri H Malthankar-Phatak
- Campus Box 8334, Department of Biomedical and Pharmaceutical Sciences, College of Pharmacy and Biomedical Research Institute, Idaho State University, Pocatello, ID 83209, USA
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17
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Suszynski TM, Wildey GM, Falde EJ, Cline GW, Maynard KS, Ko N, Sotiris J, Naji A, Hering BJ, Papas KK. The ATP/DNA ratio is a better indicator of islet cell viability than the ADP/ATP ratio. Transplant Proc 2008; 40:346-50. [PMID: 18374063 DOI: 10.1016/j.transproceed.2008.01.061] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Abstract
Real-time, accurate assessment of islet viability is critical for avoiding transplantation of nontherapeutic preparations. Measurements of the intracellular ADP/ATP ratio have been recently proposed as useful prospective estimates of islet cell viability and potency. However, dead cells may be rapidly depleted of both ATP and ADP, which would render the ratio incapable of accounting for dead cells. Since the DNA of dead cells is expected to remain stable over prolonged periods of time (days), we hypothesized that use of the ATP/DNA ratio would take into account dead cells and may be a better indicator of islet cell viability than the ADP/ATP ratio. We tested this hypothesis using mixtures of healthy and lethally heat-treated (HT) rat insulinoma cells and human islets. Measurements of ATP/DNA and ADP/ATP from the known mixtures of healthy and HT cells and islets were used to evaluate how well these parameters correlated with viability. The results indicated that ATP and ADP were rapidly (within 1 hour) depleted in HT cells. The fraction of HT cells in a mixture correlated linearly with the ATP/DNA ratio, whereas the ADP/ADP ratio was highly scattered, remaining effectively unchanged. Despite similar limitations in both ADP/ADP and ATP/DNA ratios, in that ATP levels may fluctuate significantly and reversibly with metabolic stress, the results indicated that ATP/DNA was a better measure of islet viability than the ADP/ATP ratio.
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Affiliation(s)
- T M Suszynski
- Diabetes Institute for Immunology and Transplantation, Department of Surgery, University of Minnesota, Minneapolis, Minnesota 55455, USA
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18
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Fonseca LL, Monteiro MAR, Alves PM, Carrondo MJT, Santos H. Cultures of rat astrocytes challenged with a steady supply of glutamate: New model to study flux distribution in the glutamate-glutamine cycle. Glia 2005; 51:286-96. [PMID: 15834952 DOI: 10.1002/glia.20209] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Glutamate metabolism in astrocytes was studied using an experimental setup that simulates the role of neurons (glutamate producers and glutamine consumers) by the addition of glutaminase to the culture medium. Thereby, a steady supply of glutamate was imposed at the expense of glutamine, and the stress intensity was manipulated by changing the glutaminase concentration. Glutamate supply rates in the range 8-23 nmol/min/mg protein were examined for periods of up to 48 h. When the glutamate supply rate exceeded the uptake rate of this amino acid, a transient increase in the extracellular concentration of glutamate was observed. In response to this stress, the fluxes through the glutamate transporter and glutamine synthetase were increased considerably, and the extracellular concentration of glutamate was eventually restored to a low level. The increased levels of glutamine synthetase were demonstrated by immunoblotting analysis. The effect on glutamate metabolism of the transaminase inhibitor, aminooxyacetic acid (AOAA), and of NH4Cl was also investigated. The supply of glutamate caused a concomitant reduction in the levels of phosphocreatine, phosphoethanolamine, and phosphocholine without affecting the ATP pool. Glutamine synthetase was shown to be is a key element in the control of glutamate metabolism in astrocytic cultures. The metabolic fate of glutamate depends greatly on the time of endurance to the challenge: in naive cells, glutamate was primarily metabolized through the transaminase pathway, while in well-adapted cells glutamate was converted almost exclusively through glutamine synthetase.
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Affiliation(s)
- Luís L Fonseca
- Instituto de Tecnologia Química e Biológica, Universidade Nova de Lisboa, Oeiras, Portugal
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19
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Farahani R, Pina-Benabou MH, Kyrozis A, Siddiq A, Barradas PC, Chiu FC, Cavalcante LA, Lai JCK, Stanton PK, Rozental R. Alterations in metabolism and gap junction expression may determine the role of astrocytes as ?good samaritans? or executioners. Glia 2005; 50:351-361. [PMID: 15846800 DOI: 10.1002/glia.20213] [Citation(s) in RCA: 73] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Our knowledge of astroglia and their physiological and pathophysiological role(s) in the central nervous system (CNS) has grown during the past decade, revealing a complex picture. It is becoming increasingly clear that glia play a significant role in the homeostasis and function of the CNS and that neurons should no longer be considered the only cell type that responds, both rapidly and slowly, to electrochemical activity. We discuss recent advances in the field with an emphasis on the impact of hypoxia and ischemia on astrocytic metabolism and the functional relationship between glucose metabolism and gap junctions in astrocytes. We also address the controversy over whether astrocytic gap junctions mediate protection or killing of neurons during or after hypoxic or ischemic insults.
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Affiliation(s)
- Reza Farahani
- Department of Pediatrics, Albert Einstein College of Medicine, Bronx, New York
| | - Mara H Pina-Benabou
- Department of Cell Biology and Anatomy, New York Medical College, Valhalla, New York
| | - Andreas Kyrozis
- Department of Neurology, Albert Einstein College of Medicine, Bronx, New York
| | - Ayesha Siddiq
- Department of Cell Biology and Anatomy, New York Medical College, Valhalla, New York
| | - Penha C Barradas
- Instituto de Biologia Roberto Alcantara Gomes, Universidade do Estado do Rio de Janeiro, Rio de Janeiro, Brazil
| | - Fung-Chow Chiu
- Institute of Molecular Medicine and Genetics, Medical College of Georgia, Augusta, Georgia
| | - Leny A Cavalcante
- Instituto de Biofisica C. Chagas Filho, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
| | - James C K Lai
- Department of Pharmaceutical Sciences, College of Pharmacy, Idaho State University, Pocatello, Idaho
| | - Patric K Stanton
- Department of Cell Biology and Anatomy, New York Medical College, Valhalla, New York
- Department of Neurology, New York Medical College, Valhalla, New York
| | - Renato Rozental
- Department of Cell Biology and Anatomy, New York Medical College, Valhalla, New York
- Department of Obstetrics and Anesthesiology, New York Medical College, Valhalla, New York
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20
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Kahlert S, Reiser G. Glial perspectives of metabolic states during cerebral hypoxia—calcium regulation and metabolic energy. Cell Calcium 2004; 36:295-302. [PMID: 15261485 DOI: 10.1016/j.ceca.2004.02.009] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2004] [Accepted: 02/18/2004] [Indexed: 11/23/2022]
Abstract
Cooperation between astrocytes and neurons is a unique interaction between two highly specialized cell types of the brain. Therefore, lack of nutrient supply during ischemia requires tight coordination of metabolism between astrocytes and neurons to keep the brain functions intact. To understand the impact of energy limitation on astrocytes, the functions of astrocytes have to be considered: (i) supplementation of neuronal cells, (ii) modulation of the extracellular milieu, mainly of the glutamate level, and (iii) elimination of reactive oxygen species (ROS). In cultured astrocytes and neurons inhibition of oxidative phosphorylation, using rotenone, was tested. Interestingly, this had only a negligible effect on Ca2+ homeostasis in astrocytes, even in combination with a severe glutamate stress. In contrast, in neurons glutamate in the presence of rotenone induced Ca2+ deregulation. Ca2+ homeostasis is very critical for cell survival. A massive and prolonged Ca2+ rise will lead to deregulation of many processes in such a way that the cells affected can hardly survive. Ca2+ homeostasis depends on the energy-consuming processes, which maintain the steep gradient between intracellular and extracellular Ca2+ concentration. Deprivation of oxygen and glucose during ischemia leads to a depletion of ATP in the brain, due to inhibited glycolytic and mitochondrial activity, whereas energy-consuming processes like ion pumps drain the ATP pools. On the other hand, specific mechanisms can protect brain structures against the massive insult of ischemia. Glycogen, stored in astrocytes, can maintain both neurons and astrocytes alive during short limitation of oxygen and glucose. Moreover, astrocytes can fuel ATP generation by providing lactate for neurons.
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Affiliation(s)
- Stefan Kahlert
- Institut für Neurobiochemie, Medizinische Fakultät der Otto-von-Guericke-Universität Magdeburg, Leipziger Strabetae 44, D-39120 Magdeburg, Germany
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21
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Bischof MG, Mlynarik V, Brehm A, Bernroider E, Krssak M, Bauer E, Madl C, Bayerle-Eder M, Waldhäusl W, Roden M. Brain energy metabolism during hypoglycaemia in healthy and type 1 diabetic subjects. Diabetologia 2004; 47:648-51. [PMID: 15298341 DOI: 10.1007/s00125-004-1362-2] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
AIMS/HYPOTHESIS This study aimed to examine brain energy metabolism during moderate insulin-induced hypoglycaemia in Type 1 diabetic patients and healthy volunteers. METHODS Type 1 diabetic patients (mean diabetes duration 13 +/- 2.5 years; HbA1c 6.8 +/- 0.3%) and matched controls were studied before, during (0-120 min) and after (120-240 min) hypoglycaemic (approximately 3.0 mmol/l) hyperinsulinaemic (1.5 mU x kg(-1) min(-1)) clamp tests. Brain energy metabolism was assessed by in vivo 31P nuclear magnetic resonance spectroscopy of the occipital lobe (3 Tesla, 10-cm surface coil). RESULTS During hypoglycaemia, the diabetic patients showed blunted endocrine counter-regulation. Throughout the study, the phosphocreatine:gamma-ATP ratios were lower in the diabetic patients (baseline: controls 3.08 +/- 0.29 vs diabetic patients 2.65 +/- 0.43, p<0.01; hypoglycaemia: 2.97 +/- 0.38 vs 2.60 +/- 0.35, p<0.05; recovery: 3.01 +/- 0.28 vs 2.60 +/- 0.35, p<0.01). Intracellular pH increased in both groups, being higher in diabetic patients (7.096 +/- 0.010 vs. 7.107 +/- 0.015, p<0.04), whereas intracellular magnesium concentrations decreased in both groups (controls: 377 +/- 33 vs 321 +/- 39; diabetic patients: 388 +/- 47 vs 336 +/- 68 micromol/l; p<0.05). CONCLUSIONS/INTERPRETATION Despite a lower cerebral phosphocreatine:gamma-ATP ratio in Type 1 diabetic patients at baseline, this ratio does not change in control or diabetic patients during modest hypoglycaemia. However, both groups exhibit subtle changes in intracellular pH and intracellular magnesium concentrations.
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Affiliation(s)
- M G Bischof
- Division of Endocrinology and Metabolism, Department of Internal Medicine III, University of Vienna Medical School, Austria
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22
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Sá Santos S, Fonseca LL, Monteiro MAR, Carrondo MJT, Alves PM. Culturing primary brain astrocytes under a fully controlled environment in a novel bioreactor. J Neurosci Res 2004; 79:26-32. [PMID: 15602759 DOI: 10.1002/jnr.20279] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
We report the first approach for growth and maintenance of primary astrocytes on a fully controlled environment. For this purpose, cells were immobilized in Cytodex microcarriers and grown in a stirred tank bioreactor. The distribution of astrocytes at the microcarrier surface was visualized using confocal microscopy and glial fibrillary acidic protein (GFAP) labeling, a specific glial probe. Crucial bioreaction parameters such as agitation rate, microcarrier type, and concentration, as well as cell inoculum concentration were assessed. Cytodex 3 proved the best microcarrier for astrocyte growth, with the highest cell densities obtained for 6 g/l of Cytodex 3 using an inoculum of approx. 0.15 x 10(6) cells/ml in vessels operated at 60 rpm, using a refeed operational mode consisting of complete medium replacement every 5 days. Using such optimized conditions, cells were maintained in steady-state for approximately 24 days, allowing online monitoring and control of environmental variables such as temperature, pH, and O(2). To test further the advantages of this fully controlled system, astrocytes were also subjected to hypoxic stress for 5 hr; the cell number was not affected by hypoxia but the glycolytic flux was enhanced during the stress imposed. The culture system described is a novel tool to study brain cell metabolism, allowing sampling over time and the monitoring of cellular behavior through stressful conditions and during recovery.
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Affiliation(s)
- Sónia Sá Santos
- Instituto de Biologia Experimental e Tecnológica/Instituto de Tecnologia Química e Biológica (IBET/ITQB), 2781-901 Oeiras, Portugal
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23
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Strauss KA, Morton DH. Type I glutaric aciduria, part 2: a model of acute striatal necrosis. AMERICAN JOURNAL OF MEDICAL GENETICS. PART C, SEMINARS IN MEDICAL GENETICS 2003; 121C:53-70. [PMID: 12888986 DOI: 10.1002/ajmg.c.20008] [Citation(s) in RCA: 103] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
Type I glutaric aciduria (GA1) is an inborn error of organic acid metabolism that is associated with acute neurological crises, typically precipitated by an infectious illness. The neurological crisis coincides with swelling, metabolic depression, and necrosis of basal ganglia gray matter, especially the putamina and can be visualized as focal, stroke-like, signal hyperintensity on MRI. Here we focus on the stroke-like nature of striatal necrosis and its similarity to brain injury that occurs in infants after hypoxia-ischemia or systemic intoxication with 3-nitropropionic acid (NPA). These conditions share several features including abrupt onset, preferential effect in the striatum and age-specific susceptibility. The pathophysiology of the conditions is reviewed and a model proposed herein. We encourage investigators to test this model in an appropriate experimental system.
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Affiliation(s)
- Kevin A Strauss
- Clinic for Special Children, 535 Bunker Hill Road, Strasburg, PA 17579, USA.
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24
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Corkill RG, Garnett MR, Blamire AM, Rajagopalan B, Cadoux-Hudson TAD, Styles P. Multi-modal MRI in normal pressure hydrocephalus identifies pre-operative haemodynamic and diffusion coefficient changes in normal appearing white matter correlating with surgical outcome. Clin Neurol Neurosurg 2003; 105:193-202. [PMID: 12860514 DOI: 10.1016/s0303-8467(03)00010-6] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Magnetic resonance techniques were used to investigate haemodynamic abnormalities and their consequences in normal pressure hydrocephalus (NPH) and to assess changes in these parameters following surgery. Eleven patients with NPH were studied pre- and post-operatively using perfusion and diffusion weighted imaging and compared with ten age-matched controls. Pre-operative periventricular relative cerebral blood volume (rCBV) was reduced in patients (0.76+/-0.11) compared with control (1.16+/-0.16, P<0.01). There was no difference between outcome groups and no change in haemodynamic parameters following surgery. The periventricular apparent diffusion coefficient (ADC) was elevated in the poor outcome group (1.67+/-0.3 x 10(-3) mm(2) s(-1)) compared with both controls (1.04+/-0.4 x 10(-3) mm(2) s(-1), P<0.05) and the good outcome group (0.99+/-0.3 x 10(-3) mm(2) s(-1), P<0.05) despite appearing normal on conventional imaging. In white matter hyperintensities (WMH), rCBV was reduced (0.70+/-0.12 vs. 1.00+/-0.10, P<0.01), and the ADC was increased (1.98+/-0.6 vs. 1.04+/-0.4 x 10(-3) mm(2) s(-1), P<0.05) compared with the same anatomical location in controls. As low rCBV and high ADC is characteristic of chronic infarction, the findings in WMH regions suggest they are irreversibly damaged. Normal appearing periventricular tissue rCBV was reduced, implying that significant haemodynamic consequences contribute to symptoms in NPH. The elevated pre-operative ADC of the same region, was correlated with poor outcome, and may, therefore, be useful in selecting patients for surgery.
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Affiliation(s)
- Robin G Corkill
- Department of Biochemistry, MRC Biochemical and Clinical Magnetic Resonance Unit, University of Oxford, John Radcliffe Hospital, Headington, OX3 9DU, Oxford, UK
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25
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Ghatnekar GS, Gracz HS, Smoak IW. 13C-NMR study of hypoglycemia-induced glycolytic changes in embryonic mouse heart. TERATOLOGY 2002; 66:267-72. [PMID: 12397636 DOI: 10.1002/tera.10103] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
BACKGROUND Glucose metabolites can be detected in embryonic mouse tissues using 13C-NMR spectroscopy. The advantage of this method is in its chemical specificity and the ability to follow metabolic changes. METHODS In this study, CD-1 mice were mated and embryos excised on gestational day (GD) 10.5 (plug = GD 0.5). Hearts were isolated and cultured in 150 mg/dl glucose (normoglycemic medium) or 40 mg/dl glucose (hypoglycemic medium) for 6 hr. 13C-labeled glucose comprised 62%-64% of total glucose in the culture medium. Pre- and postculture media were treated with deuterated water (D2O), and 13C spectra were obtained using a Bruker Avance 500 MHz spectrometer operating at 11.744 tesla (125.7 MHz for 13C). NMR spectra demonstrated resonances for 13C-glucose in preculture normoglycemic and hypoglycemic media. Postculture spectra for normoglycemic and hypoglycemic media demonstrated 13C-glucose signals as well as a signal for 13C-lactate. Area under the curve (AUC) was measured for the [1-(13)C-glucose] resonance from preculture media and the [3-(13)C-lactate] resonance from postculture media. The ratios of AUC for postculture [3-(13)C-lactate] to preculture [1-(13)C-glucose] were calculated and found to be higher in hypoglycemic than in normoglycemic media. RESULTS Our results confirm earlier findings using radiolabeled substrates and suggest that 13C-NMR spectroscopy can be used to study glucose metabolism in isolated embryonic hearts exposed to hypoglycemia. CONCLUSIONS NMR effectively measures glucose and its metabolite, lactate, in the same spectrum and thus determines metabolic flux in the isolated embryonic heart after exposure to hypoglycemia and normoglycemia. This method could evaluate glucose metabolism in embryonic tissues following other teratogenic exposures.
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Affiliation(s)
- Gautam S Ghatnekar
- Department of Molecular Biomedical Sciences, College of Veterinary Medicine, North Carolina State University, Raleigh, North Carolina 27606, USA.
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26
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Fonseca LL, Alves PM, Carrondo MJ, Santos H. Effect of ethanol on the metabolism of primary astrocytes studied by (13)C- and (31)P-NMR spectroscopy. J Neurosci Res 2001; 66:803-11. [PMID: 11746405 DOI: 10.1002/jnr.10039] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Nuclear magnetic resonance was used as the primary technique to investigate the effect of ethanol (40, 80, and 160 mM) on the levels of high-energy phosphates, glycolytic flux, anaplerotic and oxidative fluxes to the tricarboxylic acid (TCA) cycle, the contribution of the pentose phosphate pathway (PPP), and the uptake and release of amino acids on primary cultures of rat astrocytes. On line (31)P-NMR spectroscopy showed that long-term exposure to ethanol caused a drop in the levels of ATP and phosphocreatine. The ratio between the fluxes through the pyruvate dehydrogenase and pyruvate carboxylase reactions also decreased, whereas the glycolytic flux and the ratio between formation of lactate and glucose consumption increased when cells were exposed to acute doses of ethanol. Flux through the pentose phosphate pathway was not affected. The uptake of cysteine and the release of glutamine were stimulated by ethanol, whereas the release of methionine was inhibited. Moreover, the fractional enrichment in serine was enhanced. The changes in the amino acid metabolism are interpreted as a response to oxidative stress induced by ethanol.
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Affiliation(s)
- L L Fonseca
- Instituto de Tecnologia Química e Biológica, Universidade Nova de Lisboa, Rua de Quinta Grande, 6, 2780-156 Oeiras, Portugal
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27
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Beckmann N, Gentsch C, Baumann D, Bruttel K, Vassout A, Schoeffter P, Loetscher E, Bobadilla M, Perentes E, Rudin M. Current awareness. NMR IN BIOMEDICINE 2001; 14:217-222. [PMID: 11357188 DOI: 10.1002/nbm.669] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
In order to keep subscribers up-to-date with the latest developments in their field, John Wiley & Sons are providing a current awareness service in each issue of the journal. The bibliography contains newly published material in the field of NMR in biomedicine. Each bibliography is divided into 9 sections: 1 Books, Reviews ' Symposia; 2 General; 3 Technology; 4 Brain and Nerves; 5 Neuropathology; 6 Cancer; 7 Cardiac, Vascular and Respiratory Systems; 8 Liver, Kidney and Other Organs; 9 Muscle and Orthopaedic. Within each section, articles are listed in alphabetical order with respect to author. If, in the preceding period, no publications are located relevant to any one of these headings, that section will be omitted.
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Affiliation(s)
- N Beckmann
- Core Technologies Area, Novartis Pharma AG, CH-4002 Basel, Switzerland
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