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Bruno F, Fiorucci L, Ravera E. Sensitivity considerations on denoising series of spectra by singular value decomposition. MAGNETIC RESONANCE IN CHEMISTRY : MRC 2023; 61:373-379. [PMID: 36840610 DOI: 10.1002/mrc.5338] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/18/2023] [Revised: 02/17/2023] [Accepted: 02/22/2023] [Indexed: 05/11/2023]
Abstract
When acquiring series of spectra ( T 1 , T 2 , CP buildup curves, etc.) on samples with poor SNR, we are usually faced with choosing between taking a few points with a large number of scans to maximize the SNR or more points with a smaller number of scans to maximize the information content. In this Letter, we show how low-rank decomposition can be used to denoise a series of spectra, reducing the trade-off between the number of scans and the number of experiments.
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Affiliation(s)
- Francesco Bruno
- CERM and Department of Chemistry "Ugo Schiff", University of Florence, Sesto Fiorentino, 50019, Italy
- Consorzio Interuniversitario Risonanze Magnetiche di Metalloproteine, Sesto Fiorentino, 50019, Italy
| | - Letizia Fiorucci
- CERM and Department of Chemistry "Ugo Schiff", University of Florence, Sesto Fiorentino, 50019, Italy
- Consorzio Interuniversitario Risonanze Magnetiche di Metalloproteine, Sesto Fiorentino, 50019, Italy
| | - Enrico Ravera
- CERM and Department of Chemistry "Ugo Schiff", University of Florence, Sesto Fiorentino, 50019, Italy
- Consorzio Interuniversitario Risonanze Magnetiche di Metalloproteine, Sesto Fiorentino, 50019, Italy
- Florence Data Science, University of Florence, Firenze, 50134, Italy
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2
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Bacigaluppi M, Sferruzza G, Butti E, Ottoboni L, Martino G. Endogenous neural precursor cells in health and disease. Brain Res 2019; 1730:146619. [PMID: 31874148 DOI: 10.1016/j.brainres.2019.146619] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2019] [Revised: 11/25/2019] [Accepted: 12/19/2019] [Indexed: 12/15/2022]
Abstract
Neurogenesis persists in the adult brain of mammals in the subventricular zone (SVZ) of the lateral ventricles and in the subgranular zone (SGZ) of the dentate gyrus (DG). The complex interactions between intrinsic and extrinsic signals provided by cells in the niche but also from distant sources regulate the fate of neural stem/progenitor cells (NPCs) in these sites. This fine regulation is perturbed in aging and in pathological conditions leading to a different NPC behavior, tailored to the specific physio-pathological features. Indeed, NPCs exert in physiological and pathological conditions important neurogenic and non-neurogenic regulatory functions and participate in maintaining and protecting brain tissue homeostasis. In this review, we discuss intrinsic and extrinsic signals that regulate NPC activation and NPC functional role in various homeostatic and non-homeostatic conditions.
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Affiliation(s)
- Marco Bacigaluppi
- Neuroimmunology Unit and Department of Neurology, Institute of Experimental Neurology, San Raffaele Hospital and Università Vita- Salute San Raffaele, Via Olgettina 60, 20132 Milano, Italy.
| | - Giacomo Sferruzza
- Neuroimmunology Unit and Department of Neurology, Institute of Experimental Neurology, San Raffaele Hospital and Università Vita- Salute San Raffaele, Via Olgettina 60, 20132 Milano, Italy
| | - Erica Butti
- Neuroimmunology Unit and Department of Neurology, Institute of Experimental Neurology, San Raffaele Hospital and Università Vita- Salute San Raffaele, Via Olgettina 60, 20132 Milano, Italy
| | - Linda Ottoboni
- Neuroimmunology Unit and Department of Neurology, Institute of Experimental Neurology, San Raffaele Hospital and Università Vita- Salute San Raffaele, Via Olgettina 60, 20132 Milano, Italy
| | - Gianvito Martino
- Neuroimmunology Unit and Department of Neurology, Institute of Experimental Neurology, San Raffaele Hospital and Università Vita- Salute San Raffaele, Via Olgettina 60, 20132 Milano, Italy
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Suwabe K, Hyodo K, Byun K, Ochi G, Fukuie T, Shimizu T, Kato M, Yassa MA, Soya H. Aerobic fitness associates with mnemonic discrimination as a mediator of physical activity effects: evidence for memory flexibility in young adults. Sci Rep 2017; 7:5140. [PMID: 28698596 PMCID: PMC5506056 DOI: 10.1038/s41598-017-04850-y] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2017] [Accepted: 05/24/2017] [Indexed: 11/09/2022] Open
Abstract
A physically active lifestyle has beneficial effects on hippocampal memory function. A potential mechanism for this effect is exercise-enhanced hippocampal plasticity, particularly in the dentate gyrus (DG). Within hippocampal memory formation, the DG plays a crucial role in pattern separation, which is the ability to discriminate among similar experiences. Computational models propose a theoretical hypothesis that enhanced DG-mediated pattern separation leads to “memory flexibility”–a selective improvement in the ability to overcome moderate levels of mnemonic interference. Thus, in the current cross-sectional study of healthy young adults, we tested the working hypothesis that aerobic fitness, as a physiological indicator of endurance capacity associated with physical activity, is strongly associated with mnemonic discrimination at moderate interference levels. When divided the sample (n = 75) based on a median split of aerobic fitness, the higher fitness group had better discrimination performance for moderate interference levels compared to the lower fitness group, namely, exhibited memory flexibility. Moreover, aerobic fitness levels were positively associated with discrimination performance for moderate interference levels, as a mediator of physical activity effects. This evidence suggests that aerobic fitness levels are associated with hippocampal DG-related memory, which is consistent with literature showing positive effect of physical exercise on hippocampal memory.
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Affiliation(s)
- Kazuya Suwabe
- Laboratory of Exercise Biochemistry and Neuroendocrinology, Faculty of Health and Sport Sciences, University of Tsukuba, Ibaraki, 305-8574, Japan.,Department of Sports Neuroscience, Advanced Research Initiative for Human High Performance (ARIHHP), Faculty of Health and Sport Sciences, University of Tsukuba, Ibaraki, 305-8574, Japan
| | - Kazuki Hyodo
- Laboratory of Exercise Biochemistry and Neuroendocrinology, Faculty of Health and Sport Sciences, University of Tsukuba, Ibaraki, 305-8574, Japan.,Physical Fitness Research Institute, Meiji Yasuda Life Foundation of Health and Welfare, Tokyo, 192-0001, Japan
| | - Kyeongho Byun
- Department of Sports Neuroscience, Advanced Research Initiative for Human High Performance (ARIHHP), Faculty of Health and Sport Sciences, University of Tsukuba, Ibaraki, 305-8574, Japan.,Department of Neurobiology and Behavior, Center for the Neurobiology of Learning and Memory, University of California, Irvine, 92697-3800, CA, USA
| | - Genta Ochi
- Laboratory of Exercise Biochemistry and Neuroendocrinology, Faculty of Health and Sport Sciences, University of Tsukuba, Ibaraki, 305-8574, Japan.,Department of Sports Neuroscience, Advanced Research Initiative for Human High Performance (ARIHHP), Faculty of Health and Sport Sciences, University of Tsukuba, Ibaraki, 305-8574, Japan
| | - Takemune Fukuie
- Laboratory of Exercise Biochemistry and Neuroendocrinology, Faculty of Health and Sport Sciences, University of Tsukuba, Ibaraki, 305-8574, Japan.,Department of Sports Neuroscience, Advanced Research Initiative for Human High Performance (ARIHHP), Faculty of Health and Sport Sciences, University of Tsukuba, Ibaraki, 305-8574, Japan
| | - Takeshi Shimizu
- Sports Research & Development Core, University of Tsukuba, Ibaraki, 305-8574, Japan
| | - Morimasa Kato
- Department of Health and Nutrition, Yonezawa Nutrition University of Yamagata Prefecture, Yonezawa, 992-0025, Japan
| | - Michael A Yassa
- Department of Sports Neuroscience, Advanced Research Initiative for Human High Performance (ARIHHP), Faculty of Health and Sport Sciences, University of Tsukuba, Ibaraki, 305-8574, Japan.,Department of Neurobiology and Behavior, Center for the Neurobiology of Learning and Memory, University of California, Irvine, 92697-3800, CA, USA
| | - Hideaki Soya
- Laboratory of Exercise Biochemistry and Neuroendocrinology, Faculty of Health and Sport Sciences, University of Tsukuba, Ibaraki, 305-8574, Japan. .,Department of Sports Neuroscience, Advanced Research Initiative for Human High Performance (ARIHHP), Faculty of Health and Sport Sciences, University of Tsukuba, Ibaraki, 305-8574, Japan.
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Zhou IY, Fuss TL, Igarashi T, Jiang W, Zhou X, Cheng LL, Sun PZ. Tissue Characterization with Quantitative High-Resolution Magic Angle Spinning Chemical Exchange Saturation Transfer Z-Spectroscopy. Anal Chem 2016; 88:10379-10383. [PMID: 27709896 PMCID: PMC5441684 DOI: 10.1021/acs.analchem.6b03137] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Chemical exchange saturation transfer (CEST) provides sensitive magnetic resonance (MR) contrast for probing dilute compounds via exchangeable protons, serving as an emerging molecular imaging methodology. CEST Z-spectrum is often acquired by sweeping radiofrequency saturation around bulk water resonance, offset by offset, to detect CEST effects at characteristic chemical shift offsets, which requires prolonged acquisition time. Herein, combining high-resolution magic angle spinning (HRMAS) with concurrent application of gradient and rf saturation to achieve fast Z-spectral acquisition, we demonstrated the feasibility of fast quantitative HRMAS CEST Z-spectroscopy. The concept was validated with phantoms, which showed excellent agreement with results obtained from conventional HRMAS MR spectroscopy (MRS). We further utilized the HRMAS Z-spectroscopy for fast ex vivo quantification of ischemic injury with rodent brain tissues after ischemic stroke. This method allows rapid and quantitative CEST characterization of biological tissues and shows potential for a host of biomedical applications.
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Affiliation(s)
- Iris Yuwen Zhou
- Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital and Harvard Medical School, Charlestown, MA, USA
| | - Taylor L. Fuss
- Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital and Harvard Medical School, Charlestown, MA, USA
- Department of Pathology, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA
| | - Takahiro Igarashi
- Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital and Harvard Medical School, Charlestown, MA, USA
- Department of Neurological Surgery, Nihon University School of Medicine, Tokyo, Japan
| | - Weiping Jiang
- Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital and Harvard Medical School, Charlestown, MA, USA
- State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, National Center for Magnetic Resonance in Wuhan, Wuhan Institute of Physics and Mathematics, Chinese Academy of Sciences, Wuhan, China
| | - Xin Zhou
- State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, National Center for Magnetic Resonance in Wuhan, Wuhan Institute of Physics and Mathematics, Chinese Academy of Sciences, Wuhan, China
| | - Leo L. Cheng
- Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital and Harvard Medical School, Charlestown, MA, USA
- Department of Pathology, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA
| | - Phillip Zhe Sun
- Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital and Harvard Medical School, Charlestown, MA, USA
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5
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Dong Z. Proton MRS and MRSI of the brain without water suppression. PROGRESS IN NUCLEAR MAGNETIC RESONANCE SPECTROSCOPY 2015; 86-87:65-79. [PMID: 25919199 DOI: 10.1016/j.pnmrs.2014.12.001] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/10/2014] [Revised: 12/11/2014] [Accepted: 12/12/2014] [Indexed: 06/04/2023]
Abstract
Water suppression (WS) techniques have played a vital role in the commencement and development of in vivo proton magnetic resonance spectroscopy (MRS, including spectroscopic imaging - MRSI). WS not only made in vivo proton MRS functionally available but also made its applications conveniently accessible, and it has become an indispensable tool in most of the routine applications of in vivo proton MR spectroscopy. On the other hand, WS brought forth some challenges. Therefore, various techniques of proton MRS without WS have been developed since the pioneering work in the late 1990s. After more than one and a half decades of advances in both hardware and software, non-water-suppressed proton MRS is coming to the stage of maturity and seeing increasing application in biomedical research and clinical diagnosis. In this article, we will review progress in the technical development and applications of proton MRS without WS.
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Affiliation(s)
- Zhengchao Dong
- Division of Translational Imaging and MRI Unit, Department of Psychiatry, Columbia University, USA; Division of Translational Imaging and MRI Unit, New York State Psychiatric Institute, USA.
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Costa V, Lugert S, Jagasia R. Role of adult hippocampal neurogenesis in cognition in physiology and disease: pharmacological targets and biomarkers. Handb Exp Pharmacol 2015; 228:99-155. [PMID: 25977081 DOI: 10.1007/978-3-319-16522-6_4] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Adult hippocampal neurogenesis is a remarkable form of brain structural plasticity by which new functional neurons are generated from adult neural stem cells/precursors. Although the precise role of this process remains elusive, adult hippocampal neurogenesis is important for learning and memory and it is affected in disease conditions associated with cognitive impairment, depression, and anxiety. Immature neurons in the adult brain exhibit an enhanced structural and synaptic plasticity during their maturation representing a unique population of neurons to mediate specific hippocampal function. Compelling preclinical evidence suggests that hippocampal neurogenesis is modulated by a broad range of physiological stimuli which are relevant in cognitive and emotional states. Moreover, multiple pharmacological interventions targeting cognition modulate adult hippocampal neurogenesis. In addition, recent genetic approaches have shown that promoting neurogenesis can positively modulate cognition associated with both physiology and disease. Thus the discovery of signaling pathways that enhance adult neurogenesis may lead to therapeutic strategies for improving memory loss due to aging or disease. This chapter endeavors to review the literature in the field, with particular focus on (1) the role of hippocampal neurogenesis in cognition in physiology and disease; (2) extrinsic and intrinsic signals that modulate hippocampal neurogenesis with a focus on pharmacological targets; and (3) efforts toward novel strategies pharmacologically targeting neurogenesis and identification of biomarkers of human neurogenesis.
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Affiliation(s)
- Veronica Costa
- Roche Pharmaceutical Research and Early Development, Neuroscience Ophthalmology and Rare Diseases (NORD), Roche Innovation Center Basel, 124 Grenzacherstrasse, 4070, Basel, Switzerland
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7
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Park JH, Lee H, Makaryus R, Yu M, Smith SD, Sayed K, Feng T, Holland E, Van der Linden A, Bolwig TG, Enikolopov G, Benveniste H. Metabolic profiling of dividing cells in live rodent brain by proton magnetic resonance spectroscopy (1HMRS) and LCModel analysis. PLoS One 2014; 9:e94755. [PMID: 24819091 PMCID: PMC4018321 DOI: 10.1371/journal.pone.0094755] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2013] [Accepted: 03/19/2014] [Indexed: 02/04/2023] Open
Abstract
Rationale Dividing cells can be detected in the live brain by positron emission tomography or optical imaging. Here we apply proton magnetic resonance spectroscopy (1HMRS) and a widely used spectral fitting algorithm to characterize the effect of increased neurogenesis after electroconvulsive shock in the live rodent brain via spectral signatures representing mobile lipids resonating at ∼1.30 ppm. In addition, we also apply the same 1HMRS methodology to metabolically profile glioblastomas with actively dividing cells growing in RCAS-PDGF mice. Methods 1HMRS metabolic profiles were acquired on a 9.4T MRI instrument in combination with LCModel spectral analysis of: 1) rat brains before and after ECS or sham treatments and 2) RCAS-PDGF mice with glioblastomas and wild-type controls. Quantified 1HMRS data were compared to post-mortem histology. Results Dividing cells in the rat hippocampus increased ∼3-fold after ECS compared to sham treatment. Quantification of hippocampal metabolites revealed significant decreases in N-acetyl-aspartate but no evidence of an elevated signal at ∼1.3 ppm (Lip13a+Lip13b) in the ECS compared to the sham group. In RCAS-PDGF mice a high density (22%) of dividing cells characterized glioblastomas. Nile Red staining revealed a small fraction (3%) of dying cells with intracellular lipid droplets in the tumors of RCAS-PDGF mice. Concentrations of NAA were lower, whereas lactate and Lip13a+Lip13b were found to be significantly higher in glioblastomas of RCAS-PDGF mice, when compared to normal brain tissue in the control mice. Conclusions Metabolic profiling using 1HMRS in combination with LCModel analysis did not reveal correlation between Lip13a+Lip13b spectral signatures and an increase in neurogenesis in adult rat hippocampus after ECS. However, increases in Lip13a+Lip13b were evident in glioblastomas suggesting that a higher density of actively dividing cells and/or the presence of lipid droplets is necessary for LCModel to reveal mobile lipids.
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Affiliation(s)
- June-Hee Park
- Cold Spring Harbor Laboratory, Cold Spring Harbor, New York, United States of America
| | - Hedok Lee
- Department of Anesthesiology, Stony Brook Medicine, Stony Brook, New York, United States of America
| | - Rany Makaryus
- Department of Anesthesiology, Stony Brook Medicine, Stony Brook, New York, United States of America
| | - Mei Yu
- Department of Anesthesiology, Stony Brook Medicine, Stony Brook, New York, United States of America
| | - S. David Smith
- Department of Anesthesiology, Stony Brook Medicine, Stony Brook, New York, United States of America
| | - Kasim Sayed
- Cold Spring Harbor Laboratory, Cold Spring Harbor, New York, United States of America
| | - Tian Feng
- Department of Applied Mathematics and Statistics, Stony Brook University, New York, United States of America
| | - Eric Holland
- Division of Human Biology, Fred Hutchinson Cancer Research Center, Seattle, Washington, United States of America
| | - Annemie Van der Linden
- Department of Biomedical Sciences, Bio-Imaging Laboratory, University of Antwerp, Belgium
| | - Tom G. Bolwig
- Neuropsychiatry Laboratory, Copenhagen University Hospital, Copenhagen, Denmark
| | - Grigori Enikolopov
- Cold Spring Harbor Laboratory, Cold Spring Harbor, New York, United States of America
| | - Helene Benveniste
- Department of Anesthesiology, Stony Brook Medicine, Stony Brook, New York, United States of America
- Department of Radiology, Stony Brook Medicine, Stony Brook, New York, United States of America
- * E-mail:
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8
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Células madre: implicaciones en el desarrollo de tumores cerebrales. RADIOLOGIA 2012; 54:221-30. [DOI: 10.1016/j.rx.2011.05.014] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2011] [Accepted: 05/06/2011] [Indexed: 12/17/2022]
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9
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Matos Rojas I, Bertholdo D, Castillo M. Stem cells: Implications in the development of brain tumors. RADIOLOGIA 2012. [DOI: 10.1016/j.rxeng.2012.07.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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10
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Hepatic lipid composition differs between ob/ob and ob/+ control mice as determined by using in vivo localized proton magnetic resonance spectroscopy. MAGNETIC RESONANCE MATERIALS IN PHYSICS BIOLOGY AND MEDICINE 2012; 25:381-9. [PMID: 22441585 DOI: 10.1007/s10334-012-0310-2] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/20/2011] [Revised: 02/24/2012] [Accepted: 02/24/2012] [Indexed: 12/21/2022]
Abstract
OBJECT Hepatic lipid accumulation is associated with nonalcoholic fatty liver disease, and the metabolic syndrome constitutes an increasing medical problem. In vivo proton magnetic resonance spectroscopy ((1)H MRS) allows the assessment of hepatic lipid levels noninvasively and also yields information on the fat composition due to its high spectral resolution. MATERIALS AND METHODS We applied (1)H MRS at 9.4T to study lipid content and composition in eight leptin-deficient ob/ob mice as a model of obesity and in four lean ob/+ control mice at 24 weeks of age. PRESS sequence was used. For accurate estimation of signal intensity, differences in relaxation behavior of individual signals were accounted for each mouse individually. Also, in order to minimize spectral degrading due to motion artifacts, respiration gating was applied. RESULTS Significant differences between ob/ob and ob/+ control mice were found in both lipid content and composition. The mean chain length was found to be significantly longer in ob/ob mice with a higher fraction of monounsaturated lipids. CONCLUSION (1)H MRS enables accurate assessment in hepatic lipids in mice, which is attractive for mechanistic studies of altered metabolism given the large number of genetically engineered mouse models available.
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11
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Quantitative proton magnetic resonance spectroscopy and spectroscopic imaging of the brain: a didactic review. Top Magn Reson Imaging 2011; 21:115-28. [PMID: 21613876 DOI: 10.1097/rmr.0b013e31821e568f] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
This article presents background information related to methodology for estimating brain metabolite concentration from magnetic resonance spectroscopy (MRS) and magnetic resonance spectroscopic imaging measurements of living human brain tissue. It reviews progress related to this methodology, with emphasis placed on progress reported during the past 10 years. It is written for a target audience composed of radiologists and magnetic resonance imaging technologists. It describes in general terms the relationship between MRS signal amplitude and concentration. It then presents an overview of the many practical problems associated with deriving concentration solely from absolute measured signal amplitudes and demonstrates how a various signal calibration approaches can be successfully used. The concept of integrated signal amplitude is presented with examples that are helpful for qualitative reading of MRS data as well as for understanding the methodology used for quantitative measurements. The problems associated with the accurate measurement of individual signal amplitudes in brain spectra having overlapping signals from other metabolites and overlapping nuisance signals from water and lipid are presented. Current approaches to obtaining accurate amplitude estimates with least-squares fitting software are summarized.
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12
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Lagace DC. Does the endogenous neurogenic response alter behavioral recovery following stroke? Behav Brain Res 2011; 227:426-32. [PMID: 21907736 DOI: 10.1016/j.bbr.2011.08.045] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2011] [Revised: 08/26/2011] [Accepted: 08/29/2011] [Indexed: 12/22/2022]
Abstract
In response to stroke, the adult brain has the remarkable ability to enhance the proliferation of new cells, which form new neurons in restricted regions. This review focuses on studies that have directly tested the hypothesis that neurogenesis contributes to post-stroke behavioral recovery. The translational potential of this area of research is critically assessed with respect to the selection of appropriate stroke models, subjects, neurogenic regions examined, behavioral tests used, and experimental timecourse. Building upon those studies that suggest an association between endogeneous neurogenesis and improved stroke recovery, we are nonetheless left with the challenge to demonstrate a causal link between neurogenesis and behavioral recovery using new technology.
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Affiliation(s)
- Diane C Lagace
- Department of Cellular and Molecular Medicine, University of Ottawa, Ontario, Canada.
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13
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Couillard-Despres S, Vreys R, Aigner L, Van der Linden A. In vivo monitoring of adult neurogenesis in health and disease. Front Neurosci 2011; 5:67. [PMID: 21603226 PMCID: PMC3093743 DOI: 10.3389/fnins.2011.00067] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2011] [Accepted: 04/27/2011] [Indexed: 01/09/2023] Open
Abstract
Adult neurogenesis, i.e., the generation of new neurons in the adult brain, presents an enormous potential for regenerative therapies of the central nervous system. While 5-bromo-2'-deoxyuridine labeling and subsequent histology or immunohistochemistry for cell-type-specific markers is still the gold standard in studies of neurogenesis, novel techniques, and tools for in vivo imaging of neurogenesis have been recently developed and successfully applied. Here, we review the latest progress on these developments, in particular in the area of magnetic resonance imaging (MRI) and optical imaging. In vivo in situ labeling of neural progenitor cells (NPCs) with micron-sized iron oxide particles enables longitudinal visualization of endogenous progenitor cell migration by MRI. The possibility of genetic labeling for cellular MRI was demonstrated by using the iron storage protein ferritin as the MR reporter-gene. However, reliable and consistent results using ferritin imaging for monitoring endogenous progenitor cell migration have not yet been reported. In contrast, genetic labeling of NPCs with a fluorescent or bioluminescent reporter has led to the development of some powerful tools for in vivo imaging of neurogenesis. Here, two strategies, i.e., viral labeling of stem/progenitor cells and transgenic approaches, have been used. In addition, the use of specific promoters for neuronal progenitor cells such as doublecortin increases the neurogenesis-specificity of the labeling. Naturally, the ultimate challenge will be to develop neurogenesis imaging methods applicable in humans. Therefore, we certainly need to consider other modalities such as positron emission tomography and proton magnetic resonance spectroscopy ((1)H-MRS), which have already been implemented for both animals and humans. Further improvements of sensitivity and neurogenesis-specificity are nevertheless required for all imaging techniques currently available.
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Loewenbrück KF, Fuchs B, Hermann A, Brandt M, Werner A, Kirsch M, Schwarz S, Schwarz J, Schiller J, Storch A. Proton MR spectroscopy of neural stem cells: does the proton-NMR peak at 1.28 ppm function as a biomarker for cell type or state? Rejuvenation Res 2011; 14:371-81. [PMID: 21548757 DOI: 10.1089/rej.2010.1102] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
Recently, a peak at 1.28 ppm in proton magnetic resonance spectroscopy ((1)H-MRS) of neural stem cells (NSCs) was introduced as a noninterventional biomarker for neurogenesis in vivo. This would be an urgently needed requisite for translational studies in humans regarding the beneficial role of adult neurogenesis for the structural and functional integrity of the brain. However, many concerns have risen about the validity of the proposed signal as a specific marker for NSCs. The peak has also been related to cell-type-independent phenomena such as apoptosis or necrosis. Thus, we compared the 1.28-ppm peak in various immature stem cell populations, including embryonic stem cells, mouse embryonic fibroblasts, embryonic stem cell- and induced pluripotent stem cell-derived NSCs, ex vivo isolated embryonic NSCs, as well as mature and tumor cell types from different germ layers. To correlate the integral peak intensity with cell death, we induced both apoptosis with camptothecin and necrosis with sodium azide. A peak at 1.28 ppm was found in most cell types, and in most, but not all, NSCH cultures, demonstrating no specificity for NSCs. The intensities of the 1.28-ppm resonance significantly correlated with the rate of apoptosis, but not with the rate of necrosis, cell cycle phase distribution, cell size, or type. Multiple regression analysis displayed a significant predictive value of the peak intensity for apoptosis only. In this context, its specificity for apoptosis as a major selection process during neurogenesis may suggest this resonance as an indirect marker for neurogenesis in vivo.
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Affiliation(s)
- Kai F Loewenbrück
- Department of Neurology and Center for RegenerativeTherapies Dresden (CRTD), Dresden University of Technology, Fetscherstrasse 74, Dresden, Germany
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15
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Sierra A, Encinas JM, Maletic-Savatic M. Adult human neurogenesis: from microscopy to magnetic resonance imaging. Front Neurosci 2011; 5:47. [PMID: 21519376 PMCID: PMC3075882 DOI: 10.3389/fnins.2011.00047] [Citation(s) in RCA: 65] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2011] [Accepted: 03/23/2011] [Indexed: 01/18/2023] Open
Abstract
Neural stem cells reside in well-defined areas of the adult human brain and are capable of generating new neurons throughout the life span. In rodents, it is well established that the new born neurons are involved in olfaction as well as in certain forms of memory and learning. In humans, the functional relevance of adult human neurogenesis is being investigated, in particular its implication in the etiopathology of a variety of brain disorders. Adult neurogenesis in the human brain was discovered by utilizing methodologies directly imported from the rodent research, such as immunohistological detection of proliferation and cell-type specific biomarkers in postmortem or biopsy tissue. However, in the vast majority of cases, these methods do not support longitudinal studies; thus, the capacity of the putative stem cells to form new neurons under different disease conditions cannot be tested. More recently, new technologies have been specifically developed for the detection and quantification of neural stem cells in the living human brain. These technologies rely on the use of magnetic resonance imaging, available in hospitals worldwide. Although they require further validation in rodents and primates, these new methods hold the potential to test the contribution of adult human neurogenesis to brain function in both health and disease. This review reports on the current knowledge on adult human neurogenesis. We first review the different methods available to assess human neurogenesis, both ex vivo and in vivo and then appraise the changes of adult neurogenesis in human diseases.
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Affiliation(s)
- Amanda Sierra
- Department of Pediatrics, Baylor College of Medicine, Jan and Dan Duncan Neurological Research Institute at Texas Children's HospitalHouston, TX, USA
| | - Juan M. Encinas
- Department of Pediatrics, Baylor College of Medicine, Jan and Dan Duncan Neurological Research Institute at Texas Children's HospitalHouston, TX, USA
| | - Mirjana Maletic-Savatic
- Department of Pediatrics, Baylor College of Medicine, Jan and Dan Duncan Neurological Research Institute at Texas Children's HospitalHouston, TX, USA
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