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Duan F, Xiao Z, Wang Y, Sun X, Tang Z, Wang R, Guo L, Tang W, Liu T, Wang P, Zhan Y. Metabolic alterations in the visual pathway of retinitis pigmentosa rats: A longitudinal multimodal magnetic resonance imaging study with histopathological validation. NMR IN BIOMEDICINE 2022; 35:e4751. [PMID: 35478360 DOI: 10.1002/nbm.4751] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/25/2021] [Revised: 04/12/2022] [Accepted: 04/25/2022] [Indexed: 06/14/2023]
Abstract
Because retinitis pigmentosa (RP) has been shown to cause degenerative changes in the entire visual pathway, there is an urgent need to perform longitudinal assessments of RP-induced degeneration and identify imaging protocols to detect this degeneration as early as possible. In this study, we assessed a transgenic rat model of RP by using complementary noninvasive magnetic resonance imaging techniques, namely, proton magnetic resonance spectroscopy (1 H-MRS), to investigate the metabolic changes in RP. Our study demonstrated decreased concentrations and ratios to creatine (Cr) of N-acetylaspartate (NAA), glutamate (Glu), γ-aminobutyric acid (GABA), and taurine (Tau), whereas myo-inositol (Ins) and choline (Cho) were increased in the visual cortex of Royal College of Surgeons (RCS) rats compared with control rats (p < 0.05). Furthermore, with the progression of RP, the concentrations of NAA, Glu, GABA, and Tau, and the ratios of GABA/Cr and Tau/Cr significantly decreased over time, whereas the concentrations of Ins and Cho and the ratio of Ins/Cr significantly increased over time (p < 0.05). In addition, in RCS rats, NAA/Cr decreased significantly from 3 to 4 months postnatal (p < 0.001), and Cho/Cr increased significantly from 4 to 5 months postnatal (p = 0.005). Meanwhile, the 1 H-MRS indicators in 5-month postnatal RCS rats could be confirmed by immunohistochemical staining. In conclusion, with the progression of RP, the metabolic alterations in the visual cortex indicated progressive reprogramming with the decrease of neurons and axons, accompanied by the proliferation of gliocytes.
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Affiliation(s)
- Fei Duan
- Department of Radiology, Eye & ENT Hospital of Fudan University, Shanghai Medical School, Fudan University, Shanghai, China
| | - Zebin Xiao
- Department of Radiology, Eye & ENT Hospital of Fudan University, Shanghai Medical School, Fudan University, Shanghai, China
| | - Yuzhe Wang
- Department of Radiology, Eye & ENT Hospital of Fudan University, Shanghai Medical School, Fudan University, Shanghai, China
| | - Xinghuai Sun
- Department of Ophthalmology & Visual Science, Eye & ENT Hospital of Fudan University, Shanghai Medical School, Fudan University, Shanghai, China
- State Key Laboratory of Medical Neurobiology, Institutes of Brain Science, Fudan University, Shanghai, China
- Key Laboratory of Myopia, NHFPC (Fudan University), Shanghai, China
- Shanghai Key Laboratory of Visual Impairment and Restoration, Fudan University, Shanghai, China
| | - Zuohua Tang
- Department of Radiology, Eye & ENT Hospital of Fudan University, Shanghai Medical School, Fudan University, Shanghai, China
| | - Rong Wang
- Department of Radiology, Eye & ENT Hospital of Fudan University, Shanghai Medical School, Fudan University, Shanghai, China
- Department of Radiology, Huashan Hospital of Fudan University, Shanghai Medical School, Fudan University, Shanghai, China
| | - Linying Guo
- Department of Radiology, Eye & ENT Hospital of Fudan University, Shanghai Medical School, Fudan University, Shanghai, China
| | - Weijun Tang
- Department of Radiology, Huashan Hospital of Fudan University, Shanghai Medical School, Fudan University, Shanghai, China
| | - Tingting Liu
- Department of Ophthalmology & Visual Science, Eye & ENT Hospital of Fudan University, Shanghai Medical School, Fudan University, Shanghai, China
| | - Peng Wang
- Department of Radiology, Eye & ENT Hospital of Fudan University, Shanghai Medical School, Fudan University, Shanghai, China
| | - Yang Zhan
- Department of Radiology, Eye & ENT Hospital of Fudan University, Shanghai Medical School, Fudan University, Shanghai, China
- Shanghai Institute of Medical Imaging, Shanghai, China
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Lu J, Li Y, Zhang C, Yang X, Qiang J. Metabolic changes of the reduction of manganese intake in the hepatic encephalopathy rat: NMR- and MS-based metabolomics study. Biometals 2022; 35:935-953. [PMID: 35857253 DOI: 10.1007/s10534-022-00415-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2021] [Accepted: 06/18/2022] [Indexed: 11/29/2022]
Abstract
To investigate the metabolic changes in type C hepatic encephalopathy (CHE) rats after reducing manganese (Mn) intake. A total of 80 Sprague-Dawley rats were divided into control group and CHE groups (induced by intraperitoneal injection of thioacetamide at a dose of 250 mg/kg of body weight twice a week for 6 weeks). CHE rats were subdivided into 1Mn group (fed a standard diet, with 10 mg Mn/kg feed), 0.5Mn group (half-Mn diet), 0.25Mn group (quarter-Mn diet) and 0Mn group (no-Mn diet) for 4 to 8 weeks. Morris water maze (MWM), Y maze and narrow beam test (NBT) were used to evaluate cognitive and motor functions. Blood ammonia, brain Mn content, the number of GS-positive cells, and glutamine synthetase (GS) activity were measured. The metabolic changes of CHE rats were investigated using hydrogen-nuclear magnetic resonance and mass spectrometry. Multivariate statistical analysis was used to analyze the results. Significantly decreased numbers of entries in target area of MWM and Y maze, longer NBT latency and total time, higher blood ammonia, brain Mn content and GS activity were found in CHE rats. After reducing Mn intake, CHE rats had better behavioral performance, significantly lower blood ammonia, brain Mn content and GS activity. The main up-regulated metabolites were Ala, GABA, Glu, Gln, Lac, Tyr, Phe in 1Mn rats. After reducing Mn intake, metabolites returned to normal level at different degrees. Reducing Mn intake could reduce brain Mn content and blood ammonia, regulate GS activity and amino acid metabolism, ultimately improve behavioral performance in CHE rats.
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Affiliation(s)
- Jingjing Lu
- Department of Radiology, Jinshan Hospital of Fudan University, 1508 Longhang Road, Shanghai, 201508, China
| | - Ying Li
- Department of Radiology, Jinshan Hospital of Fudan University, 1508 Longhang Road, Shanghai, 201508, China
| | - Cui Zhang
- Department of Radiology, Jinshan Hospital of Fudan University, 1508 Longhang Road, Shanghai, 201508, China
| | - Xiuying Yang
- Department of Radiology, Jinshan Hospital of Fudan University, 1508 Longhang Road, Shanghai, 201508, China
| | - Jinwei Qiang
- Department of Radiology, Jinshan Hospital of Fudan University, 1508 Longhang Road, Shanghai, 201508, China.
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3
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Mendoza M, Shotbolt M, Faiq MA, Parra C, Chan KC. Advanced Diffusion MRI of the Visual System in Glaucoma: From Experimental Animal Models to Humans. BIOLOGY 2022; 11:454. [PMID: 35336827 PMCID: PMC8945790 DOI: 10.3390/biology11030454] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/01/2022] [Accepted: 03/10/2022] [Indexed: 11/18/2022]
Abstract
Glaucoma is a group of ophthalmologic conditions characterized by progressive retinal ganglion cell death, optic nerve degeneration, and irreversible vision loss. While intraocular pressure is the only clinically modifiable risk factor, glaucoma may continue to progress at controlled intraocular pressure, indicating other major factors in contributing to the disease mechanisms. Recent studies demonstrated the feasibility of advanced diffusion magnetic resonance imaging (dMRI) in visualizing the microstructural integrity of the visual system, opening new possibilities for non-invasive characterization of glaucomatous brain changes for guiding earlier and targeted intervention besides intraocular pressure lowering. In this review, we discuss dMRI methods currently used in visual system investigations, focusing on the eye, optic nerve, optic tract, subcortical visual brain nuclei, optic radiations, and visual cortex. We evaluate how conventional diffusion tensor imaging, higher-order diffusion kurtosis imaging, and other extended dMRI techniques can assess the neuronal and glial integrity of the visual system in both humans and experimental animal models of glaucoma, among other optic neuropathies or neurodegenerative diseases. We also compare the pros and cons of these methods against other imaging modalities. A growing body of dMRI research indicates that this modality holds promise in characterizing early glaucomatous changes in the visual system, determining the disease severity, and identifying potential neurotherapeutic targets, offering more options to slow glaucoma progression and to reduce the prevalence of this world's leading cause of irreversible but preventable blindness.
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Affiliation(s)
- Monica Mendoza
- Department of Biomedical Engineering, Tandon School of Engineering, New York University, New York, NY 11201, USA; (M.M.); (M.S.)
| | - Max Shotbolt
- Department of Biomedical Engineering, Tandon School of Engineering, New York University, New York, NY 11201, USA; (M.M.); (M.S.)
| | - Muneeb A. Faiq
- Department of Ophthalmology, NYU Grossman School of Medicine, NYU Langone Health, New York University, New York, NY 10017, USA; (M.A.F.); (C.P.)
| | - Carlos Parra
- Department of Ophthalmology, NYU Grossman School of Medicine, NYU Langone Health, New York University, New York, NY 10017, USA; (M.A.F.); (C.P.)
| | - Kevin C. Chan
- Department of Biomedical Engineering, Tandon School of Engineering, New York University, New York, NY 11201, USA; (M.M.); (M.S.)
- Department of Ophthalmology, NYU Grossman School of Medicine, NYU Langone Health, New York University, New York, NY 10017, USA; (M.A.F.); (C.P.)
- Department of Radiology, Neuroscience Institute, NYU Grossman School of Medicine, NYU Langone Health, New York University, New York, NY 10016, USA
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4
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Kang L, Wan C. Application of advanced magnetic resonance imaging in glaucoma: a narrative review. Quant Imaging Med Surg 2022; 12:2106-2128. [PMID: 35284278 PMCID: PMC8899967 DOI: 10.21037/qims-21-790] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2021] [Accepted: 11/26/2021] [Indexed: 04/02/2024]
Abstract
Glaucoma is a group of eye diseases characterized by progressive degeneration of the optic nerve head and retinal ganglion cells and corresponding visual field defects. In recent years, mounting evidence has shown that glaucoma-related damage may not be limited to the degeneration of retinal ganglion cells or the optic nerve head. The entire structure of the visual pathway may be degraded, and the degradation may even extend to some non-visual brain regions. We know that advanced morphological, functional, and metabolic magnetic resonance technologies provide a means to observe quantitatively and in real time the state of brain function. Advanced magnetic resonance imaging (MRI) techniques provide additional diagnostic markers for glaucoma, which are related to known potential histopathological changes. Many researchers in China and globally have conducted clinical and imaging studies on glaucoma. However, they are scattered, and we still need to systematically sort out the advanced MRI related to glaucoma. We reviewed literature published in any language and included all studies that were able to be translated into English from 1 January 1980 to 31 July 2021. Our literature search focused on emerging magnetic resonance neuroimaging techniques for the study of glaucoma. We then identified each functional area of the brain of glaucoma patients through the integration of anatomy, image, and function. The aim was to provide more information about the occurrence and development of glaucoma diseases. From the perspective of neuroimaging, our study provides a research basis to explain the possible mechanism of the occurrence and development of glaucoma. This knowledge gained from these techniques enables us to more clearly observe the damage glaucoma causes to the whole visual pathway. Our study provides new insights into glaucoma-induced changes to the brain. Our findings may enable the progress of these changes to be analyzed and inspire new neuroprotective therapeutic strategies for patients with glaucoma in the future.
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Affiliation(s)
- Longdan Kang
- Department of Ophthalmology, the First Hospital of China Medical University, Shenyang, China
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5
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Colbert MK, Ho LC, van der Merwe Y, Yang X, McLellan GJ, Hurley SA, Field AS, Yun H, Du Y, Conner IP, Parra C, Faiq MA, Fingert JH, Wollstein G, Schuman JS, Chan KC. Diffusion Tensor Imaging of Visual Pathway Abnormalities in Five Glaucoma Animal Models. Invest Ophthalmol Vis Sci 2021; 62:21. [PMID: 34410298 PMCID: PMC8383913 DOI: 10.1167/iovs.62.10.21] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Purpose To characterize the visual pathway integrity of five glaucoma animal models using diffusion tensor imaging (DTI). Methods Two experimentally induced and three genetically determined models of glaucoma were evaluated. For inducible models, chronic IOP elevation was achieved via intracameral injection of microbeads or laser photocoagulation of the trabecular meshwork in adult rodent eyes. For genetic models, the DBA/2J mouse model of pigmentary glaucoma, the LTBP2 mutant feline model of congenital glaucoma, and the transgenic TBK1 mouse model of normotensive glaucoma were compared with their respective genetically matched healthy controls. DTI parameters, including fractional anisotropy, axial diffusivity, and radial diffusivity, were evaluated along the optic nerve and optic tract. Results Significantly elevated IOP relative to controls was observed in each animal model except for the transgenic TBK1 mice. Significantly lower fractional anisotropy and higher radial diffusivity were observed along the visual pathways of the microbead- and laser-induced rodent models, the DBA/2J mice, and the LTBP2-mutant cats compared with their respective healthy controls. The DBA/2J mice also exhibited lower axial diffusivity, which was not observed in the other models examined. No apparent DTI change was observed in the transgenic TBK1 mice compared with controls. Conclusions Chronic IOP elevation was accompanied by decreased fractional anisotropy and increased radial diffusivity along the optic nerve or optic tract, suggestive of disrupted microstructural integrity in both inducible and genetic glaucoma animal models. The effects on axial diffusivity differed between models, indicating that this DTI metric may represent different aspects of pathological changes over time and with severity.
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Affiliation(s)
- Max K Colbert
- Department of Ophthalmology, NYU Grossman School of Medicine, NYU Langone Health, New York University, New York, New York, United States
| | - Leon C Ho
- Department of Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, United States
| | - Yolandi van der Merwe
- Department of Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, United States
| | - Xiaoling Yang
- Department of Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, United States
| | - Gillian J McLellan
- Department of Ophthalmology and Visual Sciences, University of Wisconsin - Madison, Madison, Wisconsin, United States.,McPherson Eye Research Institute, University of Wisconsin - Madison, Madison, Wisconsin, United States
| | - Samuel A Hurley
- Department of Radiology, University of Wisconsin - Madison, Madison, Wisconsin, United States
| | - Aaron S Field
- Department of Radiology, University of Wisconsin - Madison, Madison, Wisconsin, United States
| | - Hongmin Yun
- Department of Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, United States
| | - Yiqin Du
- Department of Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, United States
| | - Ian P Conner
- Department of Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, United States
| | - Carlos Parra
- Department of Ophthalmology, NYU Grossman School of Medicine, NYU Langone Health, New York University, New York, New York, United States
| | - Muneeb A Faiq
- Department of Ophthalmology, NYU Grossman School of Medicine, NYU Langone Health, New York University, New York, New York, United States
| | - John H Fingert
- Department of Ophthalmology and Visual Sciences, University of Iowa College of Medicine, Iowa City, Iowa, United States
| | - Gadi Wollstein
- Department of Ophthalmology, NYU Grossman School of Medicine, NYU Langone Health, New York University, New York, New York, United States.,Center for Neural Science, College of Arts and Science, New York University, New York, New York, United States.,Department of Biomedical Engineering, New York University Tandon School of Engineering, Brooklyn, New York, United States
| | - Joel S Schuman
- Department of Ophthalmology, NYU Grossman School of Medicine, NYU Langone Health, New York University, New York, New York, United States.,Center for Neural Science, College of Arts and Science, New York University, New York, New York, United States.,Department of Biomedical Engineering, New York University Tandon School of Engineering, Brooklyn, New York, United States.,Neuroscience Institute, NYU Grossman School of Medicine, NYU Langone Health, New York University, New York, New York, United States
| | - Kevin C Chan
- Department of Ophthalmology, NYU Grossman School of Medicine, NYU Langone Health, New York University, New York, New York, United States.,Center for Neural Science, College of Arts and Science, New York University, New York, New York, United States.,Department of Biomedical Engineering, New York University Tandon School of Engineering, Brooklyn, New York, United States.,Neuroscience Institute, NYU Grossman School of Medicine, NYU Langone Health, New York University, New York, New York, United States.,Department of Radiology, NYU Grossman School of Medicine, NYU Langone Health, New York University, New York, New York, United States
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6
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van der Merwe Y, Murphy MC, Sims JR, Faiq MA, Yang XL, Ho LC, Conner IP, Yu Y, Leung CK, Wollstein G, Schuman JS, Chan KC. Citicoline Modulates Glaucomatous Neurodegeneration Through Intraocular Pressure-Independent Control. Neurotherapeutics 2021; 18:1339-1359. [PMID: 33846961 PMCID: PMC8423893 DOI: 10.1007/s13311-021-01033-6] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/24/2021] [Indexed: 02/08/2023] Open
Abstract
Glaucoma is a neurodegenerative disease that causes progressive, irreversible vision loss. Currently, intraocular pressure (IOP) is the only modifiable risk factor for glaucoma. However, glaucomatous degeneration may continue despite adequate IOP control. Therefore, there exists a need for treatment that protects the visual system, independent of IOP. This study sought, first, to longitudinally examine the neurobehavioral effects of different magnitudes and durations of IOP elevation using multi-parametric magnetic resonance imaging (MRI), optokinetics and histology; and, second, to evaluate the effects of oral citicoline treatment as a neurotherapeutic in experimental glaucoma. Eighty-two adult Long Evans rats were divided into six groups: acute (mild or severe) IOP elevation, chronic (citicoline-treated or untreated) IOP elevation, and sham (acute or chronic) controls. We found that increasing magnitudes and durations of IOP elevation differentially altered structural and functional brain connectivity and visuomotor behavior, as indicated by decreases in fractional anisotropy in diffusion tensor MRI, magnetization transfer ratios in magnetization transfer MRI, T1-weighted MRI enhancement of anterograde manganese transport, resting-state functional connectivity, visual acuity, and neurofilament and myelin staining along the visual pathway. Furthermore, 3 weeks of oral citicoline treatment in the setting of chronic IOP elevation significantly reduced visual brain integrity loss and visual acuity decline without altering IOP. Such effects sustained after treatment was discontinued for another 3 weeks. These results not only illuminate the close interplay between eye, brain, and behavior in glaucomatous neurodegeneration, but also support a role for citicoline in protecting neural tissues and visual function in glaucoma beyond IOP control.
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Affiliation(s)
- Yolandi van der Merwe
- UPMC Eye Center, Eye and Ear Institute, Ophthalmology and Visual Science Research Center, Department of Ophthalmology, University of Pittsburgh, Pittsburgh, PA, USA
- Department of Bioengineering, Swanson School of Engineering, University of Pittsburgh, Pittsburgh, PA, USA
| | - Matthew C Murphy
- UPMC Eye Center, Eye and Ear Institute, Ophthalmology and Visual Science Research Center, Department of Ophthalmology, University of Pittsburgh, Pittsburgh, PA, USA
- Department of Radiology, Mayo Clinic, Rochester, MN, USA
| | - Jeffrey R Sims
- Department of Ophthalmology, NYU Grossman School of Medicine, NYU Langone Health, New York University, New York, NY, USA
| | - Muneeb A Faiq
- Department of Ophthalmology, NYU Grossman School of Medicine, NYU Langone Health, New York University, New York, NY, USA
| | - Xiao-Ling Yang
- UPMC Eye Center, Eye and Ear Institute, Ophthalmology and Visual Science Research Center, Department of Ophthalmology, University of Pittsburgh, Pittsburgh, PA, USA
| | - Leon C Ho
- UPMC Eye Center, Eye and Ear Institute, Ophthalmology and Visual Science Research Center, Department of Ophthalmology, University of Pittsburgh, Pittsburgh, PA, USA
| | - Ian P Conner
- UPMC Eye Center, Eye and Ear Institute, Ophthalmology and Visual Science Research Center, Department of Ophthalmology, University of Pittsburgh, Pittsburgh, PA, USA
- Department of Bioengineering, Swanson School of Engineering, University of Pittsburgh, Pittsburgh, PA, USA
| | - Yu Yu
- Pleryon Therapeutics Limited, Shenzhen, China
| | - Christopher K Leung
- University Eye Center, Hong Kong Eye Hospital, Hong Kong, China
- Department of Ophthalmology and Visual Sciences, The Chinese University of Hong Kong, Hong Kong, China
| | - Gadi Wollstein
- Department of Ophthalmology, NYU Grossman School of Medicine, NYU Langone Health, New York University, New York, NY, USA
- Center for Neural Science, College of Arts and Science, New York University, New York, NY, USA
| | - Joel S Schuman
- Department of Ophthalmology, NYU Grossman School of Medicine, NYU Langone Health, New York University, New York, NY, USA
- Center for Neural Science, College of Arts and Science, New York University, New York, NY, USA
- Neuroscience Institute, NYU Grossman School of Medicine, NYU Langone Health, New York University, New York, NY, USA
| | - Kevin C Chan
- UPMC Eye Center, Eye and Ear Institute, Ophthalmology and Visual Science Research Center, Department of Ophthalmology, University of Pittsburgh, Pittsburgh, PA, USA.
- Department of Bioengineering, Swanson School of Engineering, University of Pittsburgh, Pittsburgh, PA, USA.
- Department of Ophthalmology, NYU Grossman School of Medicine, NYU Langone Health, New York University, New York, NY, USA.
- Center for Neural Science, College of Arts and Science, New York University, New York, NY, USA.
- Department of Radiology, NYU Grossman School of Medicine, NYU Langone Health, New York University, New York, NY, USA.
- Neuroscience Institute, NYU Grossman School of Medicine, NYU Langone Health, New York University, New York, NY, USA.
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7
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Niendorf T, Beenakker JWM, Langner S, Erb-Eigner K, Bach Cuadra M, Beller E, Millward JM, Niendorf TM, Stachs O. Ophthalmic Magnetic Resonance Imaging: Where Are We (Heading To)? Curr Eye Res 2021; 46:1251-1270. [PMID: 33535828 DOI: 10.1080/02713683.2021.1874021] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Magnetic resonance imaging of the eye and orbit (MReye) is a cross-domain research field, combining (bio)physics, (bio)engineering, physiology, data sciences and ophthalmology. A growing number of reports document technical innovations of MReye and promote their application in preclinical research and clinical science. Realizing the progress and promises, this review outlines current trends in MReye. Examples of MReye strategies and their clinical relevance are demonstrated. Frontier applications in ocular oncology, refractive surgery, ocular muscle disorders and orbital inflammation are presented and their implications for explorations into ophthalmic diseases are provided. Substantial progress in anatomically detailed, high-spatial resolution MReye of the eye, orbit and optic nerve is demonstrated. Recent developments in MReye of ocular tumors are explored, and its value for personalized eye models derived from machine learning in the treatment planning of uveal melanoma and evaluation of retinoblastoma is highlighted. The potential of MReye for monitoring drug distribution and for improving treatment management and the assessment of individual responses is discussed. To open a window into the eye and into (patho)physiological processes that in the past have been largely inaccessible, advances in MReye at ultrahigh magnetic field strengths are discussed. A concluding section ventures a glance beyond the horizon and explores future directions of MReye across multiple scales, including in vivo electrolyte mapping of sodium and other nuclei. This review underscores the need for the (bio)medical imaging and ophthalmic communities to expand efforts to find solutions to the remaining unsolved problems and technical obstacles of MReye, with the objective to transfer methodological advancements driven by MR physics into genuine clinical value.
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Affiliation(s)
- Thoralf Niendorf
- MRI.TOOLS GmbH, Berlin, Germany.,Berlin Ultrahigh Field Facility, Max Delbrueck Center for Molecular Medicine in the Helmholtz Association, Berlin, Germany
| | - Jan-Willem M Beenakker
- Department of Ophthalmology and Department of Radiology, Leiden University Medical Centre, Leiden, The Netherlands
| | - Sönke Langner
- Institute of Diagnostic and Interventional Radiology, Pediatric Radiology and Neuroradiology, Rostock University Medical Center, Rostock, Germany
| | - Katharina Erb-Eigner
- Department of Radiology, Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität Zu Berlin, and Berlin Institute of Health, Berlin, Germany
| | - Meritxell Bach Cuadra
- Center for Biomedical Imaging (CIBM), Lausanne, Switzerland.,Department of Radiology, Lausanne University and University Hospital, Lausanne, Switzerland
| | - Ebba Beller
- Institute of Diagnostic and Interventional Radiology, Pediatric Radiology and Neuroradiology, Rostock University Medical Center, Rostock, Germany
| | - Jason M Millward
- Berlin Ultrahigh Field Facility, Max Delbrueck Center for Molecular Medicine in the Helmholtz Association, Berlin, Germany
| | | | - Oliver Stachs
- Department Life, Light & Matter, University Rostock, Rostock, Germany.,Department of Ophthalmology, Rostock University Medical Center, Rostock, Germany
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8
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Cinar E, Yuce B, Aslan F, Erbakan G. Neuroprotective Effect of Citicoline Eye Drops on Corneal Sensitivity After LASIK. J Refract Surg 2020; 35:764-770. [PMID: 31830292 DOI: 10.3928/1081597x-20191021-01] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2019] [Accepted: 10/21/2019] [Indexed: 11/20/2022]
Abstract
PURPOSE To evaluate the accelerator role of a topically administered neuroprotective eye drop (citicoline) on the recovery of corneal sensitivity after laser in situ keratomileusis (LASIK). METHODS In this prospective, controlled study, 78 eyes of 78 patients (mean age: 26.8 ± 7.6 years) were enrolled in the study group and their eyes were treated with topical citicoline three times a day for 1 month postoperatively. Seventy-eight eyes of 78 patients (mean age: 26.1 ± 7.4 years) were randomly selected as the control group and their eyes were treated with lubricant hyaluronic acid (0.15%) eye drops three times a day for 1 month. Corneal sensitivity was assessed in both groups using a Cochet-Bonnet esthesiometer at baseline and 1, 2, 3, 4, 6, 8, and 12 weeks after the LASIK procedure. RESULTS Corneal sensitivity at 1, 2, 3, 4, and 6 weeks after LASIK was significantly better in the citicoline group than the control group (P < .05 for all). Differences between the groups at 8 and 12 weeks after LASIK were not significant (P > .05). CONCLUSIONS Topically administered citicoline eye drops had beneficial effects in the early recovery of corneal sensitivity during the first 6 weeks after LASIK, suggesting that citicoline may play a significant role in accelerating corneal reinnervation. [J Refract Surg. 2019;35(12):764-770.].
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9
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Gandolfi S, Marchini G, Caporossi A, Scuderi G, Tomasso L, Brunoro A. Cytidine 5'-Diphosphocholine (Citicoline): Evidence for a Neuroprotective Role in Glaucoma. Nutrients 2020; 12:E793. [PMID: 32197303 PMCID: PMC7146438 DOI: 10.3390/nu12030793] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2020] [Revised: 03/10/2020] [Accepted: 03/16/2020] [Indexed: 02/07/2023] Open
Abstract
Glaucoma, a heterogeneous set of progressively degenerative optic neuropathies characterized by a loss of retinal ganglion cells (RGCs) and typical visual field deficits that can progress to blindness, is a neurodegenerative disease involving both ocular and visual brain structures. Although elevated intraocular pressure (IOP) remains the most important modifiable risk factor of primary open-angle glaucoma (POAG) and is the main therapeutic target in treating glaucoma, other factors that influence the disease course are involved and reaching the optimal IOP target does not stop the progression of glaucoma, as the visual field continues to narrow. In addition to a managed IOP, neuroprotection may be beneficial by slowing the progression of glaucoma and improving the visual defects. Citicoline (cytidine 5'-diphosphocholine) is a naturally occurring endogenous compound that has been investigated as a novel therapeutic agent for the management of glaucoma. Citicoline has demonstrated activity in a range of central neurodegenerative diseases, and experimental evidence suggests a it performs a neuromodulator and neuroprotective role on neuronal cells, including RGCs, associated with improvement in visual function, extension of the visual field and central benefits for the patient. This review aims to critically summarize the current evidence for the neuroprotective properties of citicoline in glaucoma.
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Affiliation(s)
- Stefano Gandolfi
- Ophthalmology Unit, Department of Biological, Biotechnological and Translational Sciences, University of Parma, Via Gramsci, 14, 43126 Parma, Italy;
| | - Giorgio Marchini
- Ophthalmology Unit, Department of Neurosciences, Biomedicine and Movement, University of Verona, P. le L. A. Scuro, 10, 37134 Verona, Italy;
| | - Aldo Caporossi
- Ophthalmology Unit, Catholic University of the Sacred Heart, Fondazione Policlinico Universitario A. Gemelli, Rome, Italy., Largo F. Vito 1, 00168 Rome, Italy;
| | - Gianluca Scuderi
- Ophthalmology Unit, St. Andrea Hospital, NESMOS Department, University of Rome “Sapienza”, Via di Grottarossa 1035/1039, 00189 Rome, Italy;
| | - Livia Tomasso
- Bausch & Lomb IOM spa Viale Martesana 12, 20090 Vimodrone (MI), Italy;
| | - Andrea Brunoro
- Bausch & Lomb IOM spa Viale Martesana 12, 20090 Vimodrone (MI), Italy;
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Zhang Z, Liu W, Huang Y, Luo L, Cai X, Liu Y, Ai L, Yan J, Lin S, Ye J. NLRP3 Deficiency Attenuates Secondary Degeneration of Visual Cortical Neurons Following Optic Nerve Injury. Neurosci Bull 2019; 36:277-288. [PMID: 31768783 DOI: 10.1007/s12264-019-00445-x] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2019] [Accepted: 07/26/2019] [Indexed: 01/22/2023] Open
Abstract
In the visual pathway, optic nerve (ON) injury may cause secondary degeneration of neurons in distal regions, such as the visual cortex. However, the role of the neuroinflammatory response in regulating secondary impairment in the visual cortex after ON injury remains unclear. The NOD-like receptor family pyrin domain containing 3 (NLRP3) is an important regulator of neuroinflammation. In this study, we established a mouse model of unilateral ON crush (ONC) and showed that the expression of NLRP3 was significantly increased in the primary visual cortex (V1) as a response to ONC and that the NLRP3 inflammasome was activated in the contralateral V1 1 days-14 days after ONC. Ablation of the NLRP3 gene significantly decreased the trans-neuronal degeneration within 14 days. Visual electrophysiological function was improved in NLRP3-/- mice. Taken together, these findings suggest that NLRP3 is a potential therapeutic target for protecting visual cortical neurons against degeneration after ON injury.
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Affiliation(s)
- Zhou Zhang
- Department of Ophthalmology, Research Institute of Surgery and Daping Hospital, Army Medical Center of the People's Liberation Army (PLA), Army Medical University, Chongqing, 400042, China
| | - Wenyi Liu
- Department of Ophthalmology, Research Institute of Surgery and Daping Hospital, Army Medical Center of the People's Liberation Army (PLA), Army Medical University, Chongqing, 400042, China
| | - Yubin Huang
- Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen, 518000, China
| | - Linlin Luo
- Department of Ophthalmology, Research Institute of Surgery and Daping Hospital, Army Medical Center of the People's Liberation Army (PLA), Army Medical University, Chongqing, 400042, China
| | - Xiaofeng Cai
- Department of Ophthalmology, Research Institute of Surgery and Daping Hospital, Army Medical Center of the People's Liberation Army (PLA), Army Medical University, Chongqing, 400042, China
| | - Yunjia Liu
- Department of Ophthalmology, Research Institute of Surgery and Daping Hospital, Army Medical Center of the People's Liberation Army (PLA), Army Medical University, Chongqing, 400042, China
| | - Liqianyu Ai
- Department of Ophthalmology, Research Institute of Surgery and Daping Hospital, Army Medical Center of the People's Liberation Army (PLA), Army Medical University, Chongqing, 400042, China
| | - Jun Yan
- Department 1, Research Institute of Surgery and Daping Hospital, Army Medical Center of the PLA, Army Medical University, Chongqing, 400042, China
| | - Sen Lin
- Department of Ophthalmology, Research Institute of Surgery and Daping Hospital, Army Medical Center of the People's Liberation Army (PLA), Army Medical University, Chongqing, 400042, China.
| | - Jian Ye
- Department of Ophthalmology, Research Institute of Surgery and Daping Hospital, Army Medical Center of the People's Liberation Army (PLA), Army Medical University, Chongqing, 400042, China.
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11
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Faiq MA, Wollstein G, Schuman JS, Chan KC. Cholinergic nervous system and glaucoma: From basic science to clinical applications. Prog Retin Eye Res 2019; 72:100767. [PMID: 31242454 PMCID: PMC6739176 DOI: 10.1016/j.preteyeres.2019.06.003] [Citation(s) in RCA: 69] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2019] [Revised: 06/19/2019] [Accepted: 06/21/2019] [Indexed: 02/08/2023]
Abstract
The cholinergic system has a crucial role to play in visual function. Although cholinergic drugs have been a focus of attention as glaucoma medications for reducing eye pressure, little is known about the potential modality for neuronal survival and/or enhancement in visual impairments. Citicoline, a naturally occurring compound and FDA approved dietary supplement, is a nootropic agent that is recently demonstrated to be effective in ameliorating ischemic stroke, traumatic brain injury, Parkinson's disease, Alzheimer's disease, cerebrovascular diseases, memory disorders and attention-deficit/hyperactivity disorder in both humans and animal models. The mechanisms of its action appear to be multifarious including (i) preservation of cardiolipin, sphingomyelin, and arachidonic acid contents of phosphatidylcholine and phosphatidylethanolamine, (ii) restoration of phosphatidylcholine, (iii) stimulation of glutathione synthesis, (iv) lowering glutamate concentrations and preventing glutamate excitotoxicity, (v) rescuing mitochondrial function thereby preventing oxidative damage and onset of neuronal apoptosis, (vi) synthesis of myelin leading to improvement in neuronal membrane integrity, (vii) improving acetylcholine synthesis and thereby reducing the effects of mental stress and (viii) preventing endothelial dysfunction. Such effects have vouched for citicoline as a neuroprotective, neurorestorative and neuroregenerative agent. Retinal ganglion cells are neurons with long myelinated axons which provide a strong rationale for citicoline use in visual pathway disorders. Since glaucoma is a form of neurodegeneration involving retinal ganglion cells, citicoline may help ameliorate glaucomatous damages in multiple facets. Additionally, trans-synaptic degeneration has been identified in humans and experimental models of glaucoma suggesting the cholinergic system as a new brain target for glaucoma management and therapy.
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Affiliation(s)
- Muneeb A Faiq
- Department of Ophthalmology, New York University (NYU) School of Medicine, NYU Langone Health, New York, NY, United States
| | - Gadi Wollstein
- Department of Ophthalmology, New York University (NYU) School of Medicine, NYU Langone Health, New York, NY, United States
| | - Joel S Schuman
- Department of Ophthalmology, New York University (NYU) School of Medicine, NYU Langone Health, New York, NY, United States
| | - Kevin C Chan
- Department of Ophthalmology, New York University (NYU) School of Medicine, NYU Langone Health, New York, NY, United States; Department of Radiology, New York University (NYU) School of Medicine, NYU Langone Health, New York, NY, United States; Center for Neural Science, Faculty of Arts and Science, New York University, New York, NY, United States.
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12
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Chen L, Li S, Cai F, Wu L, Gong H, Pei C, Zhou F, Zeng X. Altered functional connectivity density in primary angle-closure glaucoma patients at resting-state. Quant Imaging Med Surg 2019; 9:603-614. [PMID: 31143651 DOI: 10.21037/qims.2019.04.13] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Background Primary angle-closure glaucoma (PACG) is a neurodegenerative disease. Previous structural and functional studies of functional magnetic resonance imaging (fMRI) have demonstrated widespread dysfunction of spontaneous activity in the PACG brain. In this study, we applied a data-driven graph theory approach of functional connectivity density (FCD) mapping to investigate the altered local and global functional connectivity (FC) of the cortex in PACG. Methods Forty-five PACG patients (53.28±10.79 years, 17 males/28 females) and 46 well-matched healthy controls (HCs) (52.67±11.01 years,18 males/28 females) received resting-state fMRI scans. All PACG patients finished complete ophthalmologic examinations, including retinal nerve fiber layer thickness (RNFLT), intraocular pressure (IOP), average cup to disc ratio (A-C/D), and vertical cup to disc ratio (V-C/D). We calculated the between-group FCD difference for short-range and long-range in each voxel. Then, we generated the intrinsic FC of the seed region with the whole brain. Finally, correlations were investigated between FCD value of the altered regions and clinical variables. Results PACG patients showed increased short-range FCD in the left inferior frontal gyrus (IFG)/insula/parahippocampal gyrus and right IFG/insula (P<0.05, corrected), compared with the HCs. Simultaneously, the decreased regions in short-range FCD map were the occipital/cuneus/precuneus/superior parietal/postcentral lobe (P<0.05, corrected). In the PACG groups, decreased long-range FCD was observed in the left middle frontal gyrus compared to the HC (P<0.05, corrected). RNFLT was positively correlated with decreased short-range FCD value of the occipital/cuneus/precuneus/superior parietal/postcentral lobes, and the A-C/D was negatively correlated with the increased short-range FCD value of the left IFG/insula/parahippocampal gyrus, and the right IFG/insula. Conclusions Our findings suggest that PACG can induce extensive brain dysfunction, and showed different spatial distribution in short- and long-range FCD.
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Affiliation(s)
- Linglong Chen
- Department of Radiology, The First Affiliated Hospital, Nanchang University, Nanchang 330006, China
| | - Shenghong Li
- Department of Radiology, The First Affiliated Hospital, Nanchang University, Nanchang 330006, China
| | - Fengqin Cai
- Department of Radiology, The First Affiliated Hospital, Nanchang University, Nanchang 330006, China
| | - Lin Wu
- Department of Radiology, The First Affiliated Hospital, Nanchang University, Nanchang 330006, China
| | - Honghan Gong
- Department of Radiology, The First Affiliated Hospital, Nanchang University, Nanchang 330006, China
| | - Chonggang Pei
- Department of Ophthalmology, The First Affiliated Hospital, Nanchang University, Nanchang 330006, China
| | - Fuqing Zhou
- Department of Radiology, The First Affiliated Hospital, Nanchang University, Nanchang 330006, China.,Jiangxi Medical Imaging Research Institute, Nanchang 330006, China
| | - Xianjun Zeng
- Department of Radiology, The First Affiliated Hospital, Nanchang University, Nanchang 330006, China.,Jiangxi Medical Imaging Research Institute, Nanchang 330006, China
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13
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Kasi A, Faiq MA, Chan KC. In vivo imaging of structural, metabolic and functional brain changes in glaucoma. Neural Regen Res 2019; 14:446-449. [PMID: 30539811 PMCID: PMC6334611 DOI: 10.4103/1673-5374.243712] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
Glaucoma, the world’s leading cause of irreversible blindness, is a condition for which elevated intraocular pressure is currently the only modifiable risk factor. However, the disorder can continue to progress even at reduced intraocular pressure. This indicates additional key factors that contribute to the etiopathogenesis. There has been a growing amount of literature suggesting glaucoma as a neurodegenerative disease of the visual system. However, it remains debatable whether the observed pathophysiological conditions are causes or consequences. This review summarizes recent in vivo imaging studies that helped advance the understanding of early glaucoma involvements and disease progression in the brains of humans and experimental animal models. In particular, we focused on the non-invasive detection of early structural and functional brain changes before substantial clinical visual field loss in glaucoma patients; the eye-brain interactions across disease severity; the metabolic changes occurring in the brain’s visual system in glaucoma; and, the widespread brain involvements beyond the visual pathway as well as the potential behavioral relevance. If the mechanisms of glaucomatous brain changes are reliably identified, novel neurotherapeutics that target parameters beyond intraocular pressure lowering can be the promise of the near future, which would lead to reduced prevalence of this irreversible but preventable disease.
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Affiliation(s)
- Anisha Kasi
- NYU Langone Eye Center, Department of Ophthalmology, NYU School of Medicine, NYU Langone Health, New York University, New York, NY, USA
| | - Muneeb A Faiq
- NYU Langone Eye Center, Department of Ophthalmology, NYU School of Medicine, NYU Langone Health; Department of Radiology, NYU School of Medicine, NYU Langone Health; Center for Neural Science, Faculty of Arts and Science, New York University, New York, NY, USA
| | - Kevin C Chan
- NYU Langone Eye Center, Department of Ophthalmology, NYU School of Medicine, NYU Langone Health; Department of Radiology, NYU School of Medicine, NYU Langone Health; Center for Neural Science, Faculty of Arts and Science, New York University, New York, NY, USA
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14
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Metabolic Alterations Within the Primary Visual Cortex in Early Open-angle Glaucoma Patients. J Glaucoma 2018; 27:1046-1051. [DOI: 10.1097/ijg.0000000000001098] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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15
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Magnetic Resonance Spectroscopy Features of the Visual Pathways in Patients with Glaucoma. Clin Neuroradiol 2018; 29:615-621. [DOI: 10.1007/s00062-018-0728-7] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2018] [Accepted: 09/11/2018] [Indexed: 10/28/2022]
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16
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Li S, Wang X, Yang J, Lei H, Wang X, Xiang Y. Metabolic profile of visual cortex in diabetic rats measured with in vivo proton MRS. NMR IN BIOMEDICINE 2017; 30:e3783. [PMID: 28915340 DOI: 10.1002/nbm.3783] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/22/2016] [Revised: 07/09/2017] [Accepted: 07/10/2017] [Indexed: 06/07/2023]
Abstract
The purpose of the present study was to characterize the metabolic profile of the visual cortex in streptozotocin-induced Type 1 diabetic rats by means of in vivo proton MRS. Several metabolite concentration ratios in the visual cortex were calculated. In addition, postmortem histologic analyses for retinal ganglion cell (RGC) loss, optic nerve injury and visual cortex alterations were monitored. The results showed that diabetes induced several changes in visual cortex metabolites, such as reduced N-acetylaspartate, glutamate, γ-aminobutyric acid, taurine and choline-containing compound levels. Nevertheless, myo-inositol levels increased significantly as compared with controls. Remarkable RGC loss and optic nerve degeneration were observed by morphological analysis. Moreover, the results showed significant neuronal loss and glial activation in the visual cortex. These findings indicated that, besides vascular abnormalities, neuronal loss and degeneration in the visual pathway were induced due to disrupted glucose homeostasis in diabetes. Metabolic or functional abnormalities were induced in cerebral neurons of the visual cortex by diabetes.
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Affiliation(s)
- Shuang Li
- Department of Ophthalmology, the Central Hospital of Wuhan, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430014, China
| | - Xinghua Wang
- Department of Ophthalmology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430022, China
| | - Junjie Yang
- Department of Ophthalmology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430022, China
| | - Hao Lei
- National Center for Magnetic Resonance in Wuhan, State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, Wuhan Institute of Physics and Mathematics, Chinese Academy of Sciences, Wuhan, 430071, China
| | - Xuxia Wang
- National Center for Magnetic Resonance in Wuhan, State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, Wuhan Institute of Physics and Mathematics, Chinese Academy of Sciences, Wuhan, 430071, China
| | - Yi Xiang
- Department of Ophthalmology, the Central Hospital of Wuhan, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430014, China
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17
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Li J, Zhao C, Rao JS, Yang FX, Wang ZJ, Lei JF, Yang ZY, Li XG. Structural and metabolic changes in the traumatically injured rat brain: high-resolution in vivo proton magnetic resonance spectroscopy at 7 T. Neuroradiology 2017; 59:1203-1212. [PMID: 28856389 DOI: 10.1007/s00234-017-1915-y] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2017] [Accepted: 08/22/2017] [Indexed: 11/28/2022]
Abstract
PURPOSE The understanding of microstructural and metabolic changes in the post-traumatic brain injury is the key to brain damage suppression and repair in clinics. METHODS Ten female Wistar rats were traumatically injured in the brain CA1 region and above the cortex. Next, diffusion tensor magnetic resonance imaging (DTI) and proton magnetic resonance spectroscopy (1H MRS) were used to analyze the microstructural and metabolic changes in the brain within the following 2 weeks. RESULTS Anisotropy fraction (FA) and axial diffusivity (AD) of the corpus callosum (CC) began to decrease significantly at day 1, whereas radial diffusivity (RD) significantly increased immediately after injury, reflecting the loss of white matter integrity. Compared with day 3, RD decreased significantly at day 7, implicating the angioedema reduction. In the hippocampus, FA significantly increased at day 7; the choline-containing compounds (Cho) and myo-inositol (MI) remarkably increased at day 7 compared with those at day 3, indicating the proliferation of astrocytes and radial glial cells after day 7. No significant differences between DTI and 1H MRS parameters were observed between day 1 and day 3. CONCLUSION Day 1-3 after traumatic brain injury (TBI) may serve as a relatively appropriate time window for treatment planning and the following nerve repair.
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Affiliation(s)
- Jing Li
- Beijing Key Laboratory for Biomaterials and Neural Regeneration, School of Biological Science and Medical Engineering, Beihang University, Beijing, China
| | - Can Zhao
- Beijing Key Laboratory for Biomaterials and Neural Regeneration, School of Biological Science and Medical Engineering, Beihang University, Beijing, China
| | - Jia-Sheng Rao
- Beijing Key Laboratory for Biomaterials and Neural Regeneration, School of Biological Science and Medical Engineering, Beihang University, Beijing, China
| | - Fei-Xiang Yang
- Department of Neurobiology, School of Basic Medical Sciences, Capital Medical University, Beijing, China
| | - Zhan-Jing Wang
- Medical Experiment and Test Center, Capital Medical University, Beijing, 100069, China
| | - Jian-Feng Lei
- Medical Experiment and Test Center, Capital Medical University, Beijing, 100069, China
| | - Zhao-Yang Yang
- Department of Neurobiology, School of Basic Medical Sciences, Capital Medical University, Beijing, China
| | - Xiao-Guang Li
- Beijing Key Laboratory for Biomaterials and Neural Regeneration, School of Biological Science and Medical Engineering, Beihang University, Beijing, China. .,Department of Neurobiology, School of Basic Medical Sciences, Capital Medical University, Beijing, China.
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Venditti A, Frezza C, Celona D, Sciubba F, Foddai S, Delfini M, Serafini M, Bianco A. Phytochemical comparison with quantitative analysis between two flower phenotypes of Mentha aquatica L.: pink-violet and white. AIMS MOLECULAR SCIENCE 2017. [DOI: 10.3934/molsci.2017.3.288] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
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19
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Chen W, Zhang L, Xu YG, Zhu K, Luo M. Primary angle-closure glaucomas disturb regional spontaneous brain activity in the visual pathway: an fMRI study. Neuropsychiatr Dis Treat 2017; 13:1409-1417. [PMID: 28579788 PMCID: PMC5449125 DOI: 10.2147/ndt.s134258] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
OBJECTIVE To explore the underlying regional brain activity deficits in the visual cortex in patients with primary angle-closure glaucoma (PACG) relative to normal controls (NCs) using regional homogeneity (ReHo) method, and its relationship with behavioral performances. PATIENTS Twenty PACG patients (10 females, 10 males; mean age ± standard deviation [SD]: 54.42±9.46 years) and 20 age-, and sex status-matched NCs (10 females, 10 males; mean age ± SD: 53.75±9.16 years) were included in this study. MEASUREMENTS AND RESULTS Compared with NCs, patients with PACG showed significant atrophic peripapillary retinal nerve fiber layer (pRNFL) and neuroretinal rim area, increased optic disk cup-to-disc ratio (CDR) and optic disk volume (P<0.05), higher ReHo value in the left fusiform gyrus, left cerebellum anterior lobe, right frontal-temporal space, and right insula, and lower ReHo value in the bilateral middle occipital gyrus, left claustrum, and right paracentral lobule lobe. The receiver operating characteristic analysis revealed these different areas with high value of area under curve, and high degree of sensitivity and specificity. The mean beta values of these different areas were extracted. In PACG, the duration of disease showed a negative correlation with the mean beta value of left cerebellum anterior lobe (r=-0.453, P=0.045) and a positive correlation with right middle occipital gyrus (r=0.586, P=0.007); left middle occipital gyrus showed positive correlations with duration of disease (r=0.562, P=0.01) and left pRNFL (r=0.49, P=0.028); left claustrum had a positive correlation with left CDR (r=0.515, P=0.02); and right paracentral lobule lobe demonstrated a positive correlation with left pRNFL (r=0.623, P=0.003). CONCLUSION PACG is involved in abnormal spontaneous brain activity in multiple brain areas, and such changes are associated with clinical performances, which may reflect the underlying pathologic mechanism and play important roles in the initiation and progression of PACG.
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Affiliation(s)
- Wei Chen
- Department of Ophthalmology, Shaoxing People's Hospital, Shaoxing, Zhejiang, People's Republic of China
| | - Li Zhang
- Department of Ophthalmology, Shaoxing People's Hospital, Shaoxing, Zhejiang, People's Republic of China
| | - Yong-Gen Xu
- Department of Ophthalmology, Shaoxing People's Hospital, Shaoxing, Zhejiang, People's Republic of China
| | - Kai Zhu
- Department of Ophthalmology, Shaoxing People's Hospital, Shaoxing, Zhejiang, People's Republic of China
| | - Man Luo
- Department of Ophthalmology, Shaoxing People's Hospital, Shaoxing, Zhejiang, People's Republic of China
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20
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Jia X, Yu J, Liao SH, Duan XC. Biomechanics of the sclera and effects on intraocular pressure. Int J Ophthalmol 2016; 9:1824-1831. [PMID: 28003987 DOI: 10.18240/ijo.2016.12.21] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2016] [Accepted: 08/03/2016] [Indexed: 11/23/2022] Open
Abstract
Accumulating evidence indicates that glaucoma is a multifactorial neurodegenerative disease characterized by the loss of retinal ganglion cells (RGC), resulting in gradual and progressive permanent loss of vision. Reducing intraocular pressure (IOP) remains the only proven method for preventing and delaying the progression of glaucomatous visual impairment. However, the specific role of IOP in optic nerve injury remains controversial, and little is known about the biomechanical mechanism by which elevated IOP leads to the loss of RGC. Published studies suggest that the biomechanical properties of the sclera and scleral lamina cribrosa determine the biomechanical changes of optic nerve head, and play an important role in the pathologic process of loss of RGC and optic nerve damage. This review focuses on the current understanding of biomechanics of sclera in glaucoma and provides an overview of the possible interactions between the sclera and IOP. Treatments and interventions aimed at the sclera are also discussed.
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Affiliation(s)
- Xu Jia
- Department of Ophthalmology, the Second Xiangya Hospital, Central South University, Changsha 410011, Hunan Province, China
| | - Juan Yu
- Department of Ophthalmology, the First Hospital of Hunan University of Chinese Medicine, Changsha 410011, Hunan Province, China
| | - Sheng-Hui Liao
- School of Information Science and Engineering, Central South University, Changsha 410011, Hunan Province, China
| | - Xuan-Chu Duan
- Department of Ophthalmology, the Second Xiangya Hospital, Central South University, Changsha 410011, Hunan Province, China
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21
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Ho LC, Sigal IA, Jan NJ, Yang X, van der Merwe Y, Yu Y, Chau Y, Leung CK, Conner IP, Jin T, Wu EX, Kim SG, Wollstein G, Schuman JS, Chan KC. Non-invasive MRI Assessments of Tissue Microstructures and Macromolecules in the Eye upon Biomechanical or Biochemical Modulation. Sci Rep 2016; 6:32080. [PMID: 27561353 PMCID: PMC5000015 DOI: 10.1038/srep32080] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2016] [Accepted: 08/02/2016] [Indexed: 02/07/2023] Open
Abstract
The microstructural organization and composition of the corneoscleral shell (CSS) determine the biomechanical behavior of the eye, and are important in diseases such as glaucoma and myopia. However, limited techniques can assess these properties globally, non-invasively and quantitatively. In this study, we hypothesized that multi-modal magnetic resonance imaging (MRI) can reveal the effects of biomechanical or biochemical modulation on CSS. Upon intraocular pressure (IOP) elevation, CSS appeared hyperintense in both freshly prepared ovine eyes and living rat eyes using T2-weighted MRI. Quantitatively, transverse relaxation time (T2) of CSS increased non-linearly with IOP at 0-40 mmHg and remained longer than unloaded tissues after being unpressurized. IOP loading also increased fractional anisotropy of CSS in diffusion tensor MRI without apparent change in magnetization transfer MRI, suggestive of straightening of microstructural fibers without modification of macromolecular contents. Lastly, treatments with increasing glyceraldehyde (mimicking crosslinking conditions) and chondroitinase-ABC concentrations (mimicking glycosaminoglycan depletion) decreased diffusivities and increased magnetization transfer in cornea, whereas glyceraldehyde also increased magnetization transfer in sclera. In summary, we demonstrated the changing profiles of MRI contrast mechanisms resulting from biomechanical or biochemical modulation of the eye non-invasively. Multi-modal MRI may help evaluate the pathophysiological mechanisms in CSS and the efficacy of corneoscleral treatments.
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Affiliation(s)
- Leon C. Ho
- NeuroImaging Laboratory , University of Pittsburgh, Pittsburgh, PA, USA
- UPMC Eye Center, Ophthalmology and Visual Science Research Center, Department of Ophthalmology, School of Medicine, University of Pittsburgh, Pittsburgh, PA, USA
- Department of Electrical and Electronic Engineering, The University of Hong Kong, Hong Kong, China
| | - Ian A. Sigal
- UPMC Eye Center, Ophthalmology and Visual Science Research Center, Department of Ophthalmology, School of Medicine, University of Pittsburgh, Pittsburgh, PA, USA
- Department of Electrical and Electronic Engineering, The University of Hong Kong, Hong Kong, China
- McGowan Institute for Regenerative Medicine, University of Pittsburgh, Pittsburgh, PA, USA
- Louis J. Fox Center for Vision Restoration, University of Pittsburgh, Pittsburgh, PA, USA
| | - Ning-Jiun Jan
- UPMC Eye Center, Ophthalmology and Visual Science Research Center, Department of Ophthalmology, School of Medicine, University of Pittsburgh, Pittsburgh, PA, USA
- Department of Bioengineering, Swanson School of Engineering, University of Pittsburgh, Pittsburgh, PA, USA
| | - Xiaoling Yang
- NeuroImaging Laboratory , University of Pittsburgh, Pittsburgh, PA, USA
- UPMC Eye Center, Ophthalmology and Visual Science Research Center, Department of Ophthalmology, School of Medicine, University of Pittsburgh, Pittsburgh, PA, USA
| | - Yolandi van der Merwe
- NeuroImaging Laboratory , University of Pittsburgh, Pittsburgh, PA, USA
- UPMC Eye Center, Ophthalmology and Visual Science Research Center, Department of Ophthalmology, School of Medicine, University of Pittsburgh, Pittsburgh, PA, USA
- Department of Bioengineering, Swanson School of Engineering, University of Pittsburgh, Pittsburgh, PA, USA
- McGowan Institute for Regenerative Medicine, University of Pittsburgh, Pittsburgh, PA, USA
- Louis J. Fox Center for Vision Restoration, University of Pittsburgh, Pittsburgh, PA, USA
| | - Yu Yu
- Department of Chemical and Biomolecular Engineering, Hong Kong University of Science and Technology, Hong Kong, China
| | - Ying Chau
- Department of Chemical and Biomolecular Engineering, Hong Kong University of Science and Technology, Hong Kong, China
- Division of Biomedical Engineering, Hong Kong University of Science and Technology, Hong Kong, China
| | - Christopher K. Leung
- University Eye Center, Hong Kong Eye Hospital, Hong Kong, China
- Department of Ophthalmology and Visual Sciences, The Chinese University of Hong Kong, Hong Kong, China
| | - Ian P. Conner
- UPMC Eye Center, Ophthalmology and Visual Science Research Center, Department of Ophthalmology, School of Medicine, University of Pittsburgh, Pittsburgh, PA, USA
- McGowan Institute for Regenerative Medicine, University of Pittsburgh, Pittsburgh, PA, USA
- Louis J. Fox Center for Vision Restoration, University of Pittsburgh, Pittsburgh, PA, USA
| | - Tao Jin
- NeuroImaging Laboratory , University of Pittsburgh, Pittsburgh, PA, USA
| | - Ed X. Wu
- Department of Electrical and Electronic Engineering, The University of Hong Kong, Hong Kong, China
| | - Seong-Gi Kim
- NeuroImaging Laboratory , University of Pittsburgh, Pittsburgh, PA, USA
- Department of Bioengineering, Swanson School of Engineering, University of Pittsburgh, Pittsburgh, PA, USA
- McGowan Institute for Regenerative Medicine, University of Pittsburgh, Pittsburgh, PA, USA
- Center for the Neural Basis of Cognition, University of Pittsburgh and Carnegie Mellon University, Pittsburgh, PA, USA
- Center for Neuroscience Imaging Research, Institute for Basic Science, Suwon, Korea
- Department of Biomedical Engineering, Sungkyunkwan University, Suwon, Korea
| | - Gadi Wollstein
- UPMC Eye Center, Ophthalmology and Visual Science Research Center, Department of Ophthalmology, School of Medicine, University of Pittsburgh, Pittsburgh, PA, USA
- Department of Bioengineering, Swanson School of Engineering, University of Pittsburgh, Pittsburgh, PA, USA
- McGowan Institute for Regenerative Medicine, University of Pittsburgh, Pittsburgh, PA, USA
- Louis J. Fox Center for Vision Restoration, University of Pittsburgh, Pittsburgh, PA, USA
| | - Joel S. Schuman
- UPMC Eye Center, Ophthalmology and Visual Science Research Center, Department of Ophthalmology, School of Medicine, University of Pittsburgh, Pittsburgh, PA, USA
- Department of Bioengineering, Swanson School of Engineering, University of Pittsburgh, Pittsburgh, PA, USA
- McGowan Institute for Regenerative Medicine, University of Pittsburgh, Pittsburgh, PA, USA
- Center for the Neural Basis of Cognition, University of Pittsburgh and Carnegie Mellon University, Pittsburgh, PA, USA
- Clinical and Translational Science Institute, University of Pittsburgh, Pittsburgh, PA, USA
| | - Kevin C. Chan
- NeuroImaging Laboratory , University of Pittsburgh, Pittsburgh, PA, USA
- UPMC Eye Center, Ophthalmology and Visual Science Research Center, Department of Ophthalmology, School of Medicine, University of Pittsburgh, Pittsburgh, PA, USA
- Department of Bioengineering, Swanson School of Engineering, University of Pittsburgh, Pittsburgh, PA, USA
- McGowan Institute for Regenerative Medicine, University of Pittsburgh, Pittsburgh, PA, USA
- Louis J. Fox Center for Vision Restoration, University of Pittsburgh, Pittsburgh, PA, USA
- Center for the Neural Basis of Cognition, University of Pittsburgh and Carnegie Mellon University, Pittsburgh, PA, USA
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22
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Murphy MC, Conner IP, Teng CY, Lawrence JD, Safiullah Z, Wang B, Bilonick RA, Kim SG, Wollstein G, Schuman JS, Chan KC. Retinal Structures and Visual Cortex Activity are Impaired Prior to Clinical Vision Loss in Glaucoma. Sci Rep 2016; 6:31464. [PMID: 27510406 PMCID: PMC4980591 DOI: 10.1038/srep31464] [Citation(s) in RCA: 69] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2016] [Accepted: 07/18/2016] [Indexed: 12/14/2022] Open
Abstract
Glaucoma is the second leading cause of blindness worldwide and its pathogenesis remains unclear. In this study, we measured the structure, metabolism and function of the visual system by optical coherence tomography and multi-modal magnetic resonance imaging in healthy subjects and glaucoma patients with different degrees of vision loss. We found that inner retinal layer thinning, optic nerve cupping and reduced visual cortex activity occurred before patients showed visual field impairment. The primary visual cortex also exhibited more severe functional deficits than higher-order visual brain areas in glaucoma. Within the visual cortex, choline metabolism was perturbed along with increasing disease severity in the eye, optic radiation and visual field. In summary, this study showed evidence that glaucoma deterioration is already present in the eye and the brain before substantial vision loss can be detected clinically using current testing methods. In addition, cortical cholinergic abnormalities are involved during trans-neuronal degeneration and can be detected non-invasively in glaucoma. The current results can be of impact for identifying early glaucoma mechanisms, detecting and monitoring pathophysiological events and eye-brain-behavior relationships, and guiding vision preservation strategies in the visual system, which may help reduce the burden of this irreversible but preventable neurodegenerative disease.
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Affiliation(s)
- Matthew C Murphy
- NeuroImaging Laboratory, University of Pittsburgh, Pittsburgh, PA, USA.,UPMC Eye Center, Ophthalmology and Visual Science Research Center, Department of Ophthalmology, School of Medicine, University of Pittsburgh, Pittsburgh, PA, USA.,Louis J. Fox Center for Vision Restoration, University of Pittsburgh, PA, USA
| | - Ian P Conner
- NeuroImaging Laboratory, University of Pittsburgh, Pittsburgh, PA, USA.,UPMC Eye Center, Ophthalmology and Visual Science Research Center, Department of Ophthalmology, School of Medicine, University of Pittsburgh, Pittsburgh, PA, USA.,Louis J. Fox Center for Vision Restoration, University of Pittsburgh, PA, USA.,Department of Bioengineering, Swanson School of Engineering, University of Pittsburgh, PA, USA
| | - Cindy Y Teng
- NeuroImaging Laboratory, University of Pittsburgh, Pittsburgh, PA, USA.,UPMC Eye Center, Ophthalmology and Visual Science Research Center, Department of Ophthalmology, School of Medicine, University of Pittsburgh, Pittsburgh, PA, USA
| | - Jesse D Lawrence
- NeuroImaging Laboratory, University of Pittsburgh, Pittsburgh, PA, USA.,UPMC Eye Center, Ophthalmology and Visual Science Research Center, Department of Ophthalmology, School of Medicine, University of Pittsburgh, Pittsburgh, PA, USA
| | - Zaid Safiullah
- NeuroImaging Laboratory, University of Pittsburgh, Pittsburgh, PA, USA.,UPMC Eye Center, Ophthalmology and Visual Science Research Center, Department of Ophthalmology, School of Medicine, University of Pittsburgh, Pittsburgh, PA, USA
| | - Bo Wang
- UPMC Eye Center, Ophthalmology and Visual Science Research Center, Department of Ophthalmology, School of Medicine, University of Pittsburgh, Pittsburgh, PA, USA.,Louis J. Fox Center for Vision Restoration, University of Pittsburgh, PA, USA.,Department of Bioengineering, Swanson School of Engineering, University of Pittsburgh, PA, USA
| | - Richard A Bilonick
- UPMC Eye Center, Ophthalmology and Visual Science Research Center, Department of Ophthalmology, School of Medicine, University of Pittsburgh, Pittsburgh, PA, USA.,Department of Biostatistics, Graduate School of Public Health, University of Pittsburgh, PA, USA
| | - Seong-Gi Kim
- NeuroImaging Laboratory, University of Pittsburgh, Pittsburgh, PA, USA.,Department of Bioengineering, Swanson School of Engineering, University of Pittsburgh, PA, USA.,McGowan Institute for Regenerative Medicine, University of Pittsburgh, PA, USA.,Center for Neuroscience Imaging Research, Institute for Basic Science, Suwon, Korea.,Department of Biomedical Engineering, Sungkyunkwan University, Suwon, Korea
| | - Gadi Wollstein
- UPMC Eye Center, Ophthalmology and Visual Science Research Center, Department of Ophthalmology, School of Medicine, University of Pittsburgh, Pittsburgh, PA, USA.,Louis J. Fox Center for Vision Restoration, University of Pittsburgh, PA, USA.,Department of Bioengineering, Swanson School of Engineering, University of Pittsburgh, PA, USA
| | - Joel S Schuman
- UPMC Eye Center, Ophthalmology and Visual Science Research Center, Department of Ophthalmology, School of Medicine, University of Pittsburgh, Pittsburgh, PA, USA.,Louis J. Fox Center for Vision Restoration, University of Pittsburgh, PA, USA.,Department of Bioengineering, Swanson School of Engineering, University of Pittsburgh, PA, USA.,McGowan Institute for Regenerative Medicine, University of Pittsburgh, PA, USA.,Clinical and Translational Science Institute, University of Pittsburgh, Pittsburgh, PA, USA.,Center for the Neural Basis of Cognition, University of Pittsburgh and Carnegie Mellon University, Pittsburgh, PA, USA
| | - Kevin C Chan
- NeuroImaging Laboratory, University of Pittsburgh, Pittsburgh, PA, USA.,UPMC Eye Center, Ophthalmology and Visual Science Research Center, Department of Ophthalmology, School of Medicine, University of Pittsburgh, Pittsburgh, PA, USA.,Louis J. Fox Center for Vision Restoration, University of Pittsburgh, PA, USA.,Department of Bioengineering, Swanson School of Engineering, University of Pittsburgh, PA, USA.,McGowan Institute for Regenerative Medicine, University of Pittsburgh, PA, USA.,Center for the Neural Basis of Cognition, University of Pittsburgh and Carnegie Mellon University, Pittsburgh, PA, USA
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23
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In vivo proton magnetic resonance spectroscopy (1H-MRS) evaluation of the metabolite concentration of optic radiation in primary open angle glaucoma. Eur Radiol 2016; 26:4404-4412. [PMID: 26943134 PMCID: PMC5101279 DOI: 10.1007/s00330-016-4279-5] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2015] [Revised: 02/04/2016] [Accepted: 02/08/2016] [Indexed: 10/26/2022]
Abstract
OBJECTIVE To compare the metabolite concentration of optic radiation in glaucoma patients with that of healthy subjects using Proton Magnetic Resonance Spectroscopy (1H-MRS). METHODS 1H-MRS utilising the Single-Voxel Spectroscopy (SVS) technique was performed using a 3.0Tesla MRI on 45 optic radiations (15 from healthy subjects, 15 from mild glaucoma patients, and 15 from severe glaucoma patients). A standardised Volume of Interest (VOI) of 20 × 20 × 20 mm was placed in the region of optic radiation. Mild and severe glaucoma patients were categorised based on the Hodapp-Parrish-Anderson (HPA) classification. Mean and multiple group comparisons for metabolite concentration and metabolite concentration ratio between glaucoma grades and healthy subjects were obtained using one-way ANOVA. RESULTS The metabolite concentration and metabolite concentration ratio between the optic radiations of glaucoma patients and healthy subjects did not demonstrate any significant difference (p > 0.05). CONCLUSION Our findings show no significant alteration of metabolite concentration associated with neurodegeneration that could be measured by single-voxel 1H-MRS in optic radiation among glaucoma patients. KEY POINTS • Glaucoma disease has a neurodegenerative component. • Metabolite changes have been observed in the neurodegenerative process in the brain. • Using SVS, no metabolite changes in optic radiation were attributed to glaucoma.
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Network Centrality of Resting-State fMRI in Primary Angle-Closure Glaucoma Before and After Surgery. PLoS One 2015; 10:e0141389. [PMID: 26506229 PMCID: PMC4624709 DOI: 10.1371/journal.pone.0141389] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2015] [Accepted: 10/06/2015] [Indexed: 12/20/2022] Open
Abstract
Purpose Using voxel-wise degree centrality (DC), as measured by resting-state fMRI, we aimed to study alterations in the brain functional networks in patients with primary angle-closure glaucoma (PACG) and to reveal the plastic trajectories of surgery. Methods A total of 23 preoperative PACG patients (49.48 ± 14.37 years old) were recruited to undergo a resting-state fMRI scan, and 9 of them were rescanned 3 months after surgery. All PACG patients underwent a complete ophthalmologic examination, including intraocular pressure (IOP), retinal nerve fiber layer (RNFL) thickness, vertical cup to disc ratio (V C/D), and average cup to disc ratio (A C/D). Another 23 gender- and age-matched healthy controls (48.18 ± 9.40 years old) underwent scanning once for comparison. The group difference in DC was calculated in each voxel, and the correlations between the DC value and each of the clinical variables were analyzed in the PACG patients. Results Preoperative PACG (pre-PACG) patients showed significantly decreased DC in the bilateral visual cortices but increased DC in the left anterior cingulate cortex (ACC) and caudate (p < 0.05, corrected) compared with the controls. Statistical analysis showed a significantly negative correlation between DC in the bilateral visual cortices and the IOP score and between DC in the anterior cingulate cortex (ACC) and both the A C/D and V C/D scores in the pre-PACG patients. Three months after surgery, these postoperative PACG (post-PACG) patients showed a significantly increased DC in both the bilateral visual cortices and the left precentral gyrus compared with the pre-PACG patients. Conclusions Our results suggest that PACG may contribute to decreased functional centrality in the visual system and to increased degree centrality in cognition-emotional processing regions. Alterations in visual areas seem to parallel the cup to disc ratio, but not the duration of angle closure. The changes of functional centrality in PACG patients after operation may reveal the plasticity or degeneration of the visual-associated brain areas. Our findings may provide further understanding of the pathophysiology of PACG.
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25
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Ho LC, Wang B, Conner IP, van der Merwe Y, Bilonick RA, Kim SG, Wu EX, Sigal IA, Wollstein G, Schuman JS, Chan KC. In Vivo Evaluation of White Matter Integrity and Anterograde Transport in Visual System After Excitotoxic Retinal Injury With Multimodal MRI and OCT. Invest Ophthalmol Vis Sci 2015; 56:3788-800. [PMID: 26066747 DOI: 10.1167/iovs.14-15552] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
PURPOSE Excitotoxicity has been linked to the pathogenesis of ocular diseases and injuries and may involve early degeneration of both anterior and posterior visual pathways. However, their spatiotemporal relationships remain unclear. We hypothesized that the effects of excitotoxic retinal injury (ERI) on the visual system can be revealed in vivo by diffusion tensor magnetic resonance imagining (DTI), manganese-enhanced magnetic resonance imagining (MRI), and optical coherence tomography (OCT). METHODS Diffusion tensor MRI was performed at 9.4 Tesla to monitor white matter integrity changes after unilateral N-methyl-D-aspartate (NMDA)-induced ERI in six Sprague-Dawley rats and six C57BL/6J mice. Additionally, four rats and four mice were intravitreally injected with saline to compare with NMDA-injected animals. Optical coherence tomography of the retina and manganese-enhanced MRI of anterograde transport were evaluated and correlated with DTI parameters. RESULTS In the rat optic nerve, the largest axial diffusivity decrease and radial diffusivity increase occurred within the first 3 and 7 days post ERI, respectively, suggestive of early axonal degeneration and delayed demyelination. The optic tract showed smaller directional diffusivity changes and weaker DTI correlations with retinal thickness compared with optic nerve, indicative of anterograde degeneration. The splenium of corpus callosum was also reorganized at 4 weeks post ERI. The DTI profiles appeared comparable between rat and mouse models. Furthermore, the NMDA-injured visual pathway showed reduced anterograde manganese transport, which correlated with diffusivity changes along but not perpendicular to optic nerve. CONCLUSIONS Diffusion tensor MRI, manganese-enhanced MRI, and OCT provided an in vivo model system for characterizing the spatiotemporal changes in white matter integrity, the eye-brain relationships and structural-physiological relationships in the visual system after ERI.
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Affiliation(s)
- Leon C Ho
- NeuroImaging Laboratory, University of Pittsburgh, Pittsburgh, Pennsylvania, United States 2UPMC Eye Center, Ophthalmology and Visual Science Research Center, Department of Ophthalmology, School of Medicine, University of Pittsburgh, Pittsburgh, Pennsylva
| | - Bo Wang
- UPMC Eye Center, Ophthalmology and Visual Science Research Center, Department of Ophthalmology, School of Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania, United States 4Department of Bioengineering, Swanson School of Engineering, University
| | - Ian P Conner
- UPMC Eye Center, Ophthalmology and Visual Science Research Center, Department of Ophthalmology, School of Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania, United States 4Department of Bioengineering, Swanson School of Engineering, University
| | - Yolandi van der Merwe
- NeuroImaging Laboratory, University of Pittsburgh, Pittsburgh, Pennsylvania, United States 2UPMC Eye Center, Ophthalmology and Visual Science Research Center, Department of Ophthalmology, School of Medicine, University of Pittsburgh, Pittsburgh, Pennsylva
| | - Richard A Bilonick
- UPMC Eye Center, Ophthalmology and Visual Science Research Center, Department of Ophthalmology, School of Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania, United States 4Department of Bioengineering, Swanson School of Engineering, University
| | - Seong-Gi Kim
- NeuroImaging Laboratory, University of Pittsburgh, Pittsburgh, Pennsylvania, United States 4Department of Bioengineering, Swanson School of Engineering, University of Pittsburgh, Pittsburgh, Pennsylvania, United States 6McGowan Institute for Regenerative
| | - Ed X Wu
- Department of Electrical and Electronic Engineering, The University of Hong Kong, Pokfulam, Hong Kong, China
| | - Ian A Sigal
- UPMC Eye Center, Ophthalmology and Visual Science Research Center, Department of Ophthalmology, School of Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania, United States 4Department of Bioengineering, Swanson School of Engineering, University
| | - Gadi Wollstein
- UPMC Eye Center, Ophthalmology and Visual Science Research Center, Department of Ophthalmology, School of Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania, United States 5Louis J. Fox Center for Vision Restoration, University of Pittsburgh, Pi
| | - Joel S Schuman
- UPMC Eye Center, Ophthalmology and Visual Science Research Center, Department of Ophthalmology, School of Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania, United States 4Department of Bioengineering, Swanson School of Engineering, University
| | - Kevin C Chan
- NeuroImaging Laboratory, University of Pittsburgh, Pittsburgh, Pennsylvania, United States 2UPMC Eye Center, Ophthalmology and Visual Science Research Center, Department of Ophthalmology, School of Medicine, University of Pittsburgh, Pittsburgh, Pennsylva
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Liu Z, Tian J. Amplitude of low frequency fluctuation in primary open angle glaucoma: a resting state fMRI study. ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. ANNUAL INTERNATIONAL CONFERENCE 2015; 2014:6706-9. [PMID: 25571535 DOI: 10.1109/embc.2014.6945167] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Primary open angle glaucoma (POAG) is a kind of progressive neuropathy with no clear cause. In the present fMRI study, a data-driven approach was employed to map the alteration of regional spontaneous activity in POAG patients by measuring the amplitude of low-frequency fluctuation (ALFF) of the blood oxygen level-dependent (BOLD) signal. Twenty one POAG patients and 22 age and gender matched healthy subjects participated in this study. We found that the abnormal ALFF values in the POAG patients compared with healthy controls were not only detected in the visual regions but also across the whole brain. We also found the correlations between ALFF values and the POAG stages for POAG patients. We concluded that the abnormality of spontaneous brain activity in patients with POAG existed in visual cortex as well as in distal brain regions associated with sensation, motion, emotion and psychology. And the abnormal spontaneous neural activity in different brain regions could be better detected by specific frequency bands. These findings might contribute to a better understanding of the pathophysiology of POAG.
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Dekeyster E, Aerts J, Valiente-Soriano FJ, De Groef L, Vreysen S, Salinas-Navarro M, Vidal-Sanz M, Arckens L, Moons L. Ocular hypertension results in retinotopic alterations in the visual cortex of adult mice. Curr Eye Res 2015; 40:1269-83. [PMID: 25615273 DOI: 10.3109/02713683.2014.990983] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
PURPOSE Glaucoma is a group of optic neuropathies characterized by the loss of retinal ganglion cells (RGCs). Since ocular hypertension (OHT) is a main risk factor, current therapies are predominantly based on lowering eye pressure. However, a subset of treated patients continues to lose vision. More research into pathological mechanisms underlying glaucoma is therefore warranted in order to develop novel therapeutic strategies. In this study we investigated the impact of OHT from eye to brain in mice. METHODS Monocular hypertension (mOHT) was induced in CD-1 mice by laser photocoagulation (LP) of the perilimbal and episcleral veins. The impact on the retina and its main direct target area, the superficial superior colliculus (sSC), was examined via immunostainings for Brn3a, VGluT2 and GFAP. Alterations in neuronal activity in V1 and extrastriate areas V2L and V2M were assessed using in situ hybridization for the activity reporter gene zif268. RESULTS Transient mOHT resulted in diffuse and sectorial RGC degeneration. In the sSC contralateral to the OHT eye, a decrease in VGluT2 immunopositive synaptic connections was detected one week post LP, which appeared to be retinotopically linked to the sectorial RGC degeneration patterns. In parallel, hypoactivity was discerned in contralateral retinotopic projection zones in V1 and V2. Despite complete cortical reactivation 4 weeks post LP, in the sSC no evidence for recovery of RGC synapse density was found and also the concomitant inflammation was not completely resolved. Nevertheless, sSC neurons appeared healthy upon histological inspection and subsequent analysis of cell density revealed no differences between the ipsi- and contralateral sSC. CONCLUSION In addition to RGC death, OHT induces loss of synaptic connections and neuronal activity in the visual pathway and is accompanied by an extensive immune response. Our findings stress the importance of looking beyond the eye and including the whole visual system in glaucoma research.
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Affiliation(s)
- Eline Dekeyster
- a Neural Circuit Development and Regeneration Research Group, Department of Biology, KU Leuven , Leuven , Belgium
| | - Jeroen Aerts
- b Laboratory of Neuroplasticity and Neuroproteomics, Department of Biology , KU Leuven , Leuven , Belgium and
| | | | - Lies De Groef
- a Neural Circuit Development and Regeneration Research Group, Department of Biology, KU Leuven , Leuven , Belgium
| | - Samme Vreysen
- b Laboratory of Neuroplasticity and Neuroproteomics, Department of Biology , KU Leuven , Leuven , Belgium and
| | - Manuel Salinas-Navarro
- a Neural Circuit Development and Regeneration Research Group, Department of Biology, KU Leuven , Leuven , Belgium
| | - Manuel Vidal-Sanz
- c Department of Ophthalmology , University of Murcia and IMIB-Arrixaca , Murcia , Spain
| | - Lutgarde Arckens
- b Laboratory of Neuroplasticity and Neuroproteomics, Department of Biology , KU Leuven , Leuven , Belgium and
| | - Lieve Moons
- a Neural Circuit Development and Regeneration Research Group, Department of Biology, KU Leuven , Leuven , Belgium
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Brain imaging in glaucoma from clinical studies to clinical practice. PROGRESS IN BRAIN RESEARCH 2015; 221:159-75. [DOI: 10.1016/bs.pbr.2015.06.004] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
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Chan KC, Kancherla S, Fan SJ, Wu EX. Long-term effects of neonatal hypoxia-ischemia on structural and physiological integrity of the eye and visual pathway by multimodal MRI. Invest Ophthalmol Vis Sci 2014; 56:1-9. [PMID: 25491295 DOI: 10.1167/iovs.14-14287] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
PURPOSE Neonatal hypoxia-ischemia is a major cause of brain damage in infants and may frequently present visual impairments. Although advancements in perinatal care have increased survival, the pathogenesis of hypoxic-ischemic injury and the long-term consequences to the visual system remain unclear. We hypothesized that neonatal hypoxia-ischemia can lead to chronic, MRI-detectable structural and physiological alterations in both the eye and the brain's visual pathways. METHODS Eight Sprague-Dawley rats underwent ligation of the left common carotid artery followed by hypoxia for 2 hours at postnatal day 7. One year later, T2-weighted MRI, gadolinium-enhanced MRI, chromium-enhanced MRI, manganese-enhanced MRI, and diffusion tensor MRI (DTI) of the visual system were evaluated and compared between opposite hemispheres using a 7-Tesla scanner. RESULTS Within the eyeball, systemic gadolinium administration revealed aqueous-vitreous or blood-ocular barrier leakage only in the ipsilesional left eye despite comparable aqueous humor dynamics in the anterior chamber of both eyes. Binocular intravitreal chromium injection showed compromised retinal integrity in the ipsilesional eye. Despite total loss of the ipsilesional visual cortex, both retinocollicular and retinogeniculate pathways projected from the contralesional eye toward ipsilesional visual cortex possessed stronger anterograde manganese transport and less disrupted structural integrity in DTI compared with the opposite hemispheres. CONCLUSIONS High-field, multimodal MRI demonstrated in vivo the long-term structural and physiological deficits in the eye and brain's visual pathways after unilateral neonatal hypoxic-ischemic injury. The remaining retinocollicular and retinogeniculate pathways appeared to be more vulnerable to anterograde degeneration from eye injury than retrograde, transsynaptic degeneration from visual cortex injury.
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Affiliation(s)
- Kevin C Chan
- UPMC Eye Center, Ophthalmology and Visual Science Research Center, Department of Ophthalmology, School of Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania, United States
| | - Swarupa Kancherla
- UPMC Eye Center, Ophthalmology and Visual Science Research Center, Department of Ophthalmology, School of Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania, United States
| | - Shu-Juan Fan
- Laboratory of Biomedical Imaging and Signal Processing, The University of Hong Kong, Pokfulam, Hong Kong SAR, China Department of Electrical and Electronic Engineering, The University of Hong Kong, Pokfulam, Hong Kong SAR, China
| | - Ed X Wu
- Laboratory of Biomedical Imaging and Signal Processing, The University of Hong Kong, Pokfulam, Hong Kong SAR, China Department of Electrical and Electronic Engineering, The University of Hong Kong, Pokfulam, Hong Kong SAR, China
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Li K, Lu C, Huang Y, Yuan L, Zeng D, Wu K. Alteration of fractional anisotropy and mean diffusivity in glaucoma: novel results of a meta-analysis of diffusion tensor imaging studies. PLoS One 2014; 9:e97445. [PMID: 24828063 PMCID: PMC4020845 DOI: 10.1371/journal.pone.0097445] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2014] [Accepted: 04/20/2014] [Indexed: 12/31/2022] Open
Abstract
OBJECTIVES We hypothesized that a meta-analysis of existing studies may help to reveal significant changes on diffusion tensor imaging (DTI) in patients with glaucoma. Therefore, a meta-analysis was utilized to investigate the possibility that DTI can detect white matter damage in patients with glaucoma. METHODS The study design and report adhered to the PRISMA Statement guidelines. DTI studies that compared glaucoma patients and controls were surveyed using PubMed, Web of Science and EMBASE (January 2008 to September 2013). Stata was used to analyze the decrease in fractional anisotropy (FA) and increase in mean diffusivity (MD) in the optic nerve and optic radiation in patients with glaucoma. RESULTS Eleven DTI studies were identified through a comprehensive literature search, and 10 independent DTI studies of glaucoma patients were eligible for the meta-analysis. A random effects model revealed a significant FA reduction in the optic nerve and optic radiation, as well as a significant MD increase in the tracts. A heterogeneity analysis suggested that FA may be related to glaucoma severity. CONCLUSIONS Our findings revealed that the optic nerve and optic radiation were vulnerable regions in patients with glaucoma and that FA may be correlated with glaucoma severity and age. Furthermore, this study suggests that magnetic resonance imaging in patients with glaucoma may help to provide objective evidence to aid in the diagnosis and management of glaucoma.
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Affiliation(s)
- Ke Li
- Key Laboratory for NeuroInformation of Ministry of Education, University of Electronic Science and Technology of China, Chengdu, China
- School of Life Science and Technology, University of Electronic Science and Technology of China, Chengdu, China
| | - Cuixin Lu
- School of Life Science and Technology, University of Electronic Science and Technology of China, Chengdu, China
| | - Yufei Huang
- School of Life Science and Technology, University of Electronic Science and Technology of China, Chengdu, China
| | - Li Yuan
- School of Life Science and Technology, University of Electronic Science and Technology of China, Chengdu, China
| | - Dong Zeng
- Key Laboratory for NeuroInformation of Ministry of Education, University of Electronic Science and Technology of China, Chengdu, China
- School of Life Science and Technology, University of Electronic Science and Technology of China, Chengdu, China
| | - Kan Wu
- School of Life Science and Technology, University of Electronic Science and Technology of China, Chengdu, China
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Roberti G, Tanga L, Parisi V, Sampalmieri M, Centofanti M, Manni G. A preliminary study of the neuroprotective role of citicoline eye drops in glaucomatous optic neuropathy. Indian J Ophthalmol 2014; 62:549-53. [PMID: 24881599 PMCID: PMC4065503 DOI: 10.4103/0301-4738.133484] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2013] [Accepted: 02/16/2014] [Indexed: 11/29/2022] Open
Abstract
PURPOSE To study the neuroprotective effect of topical citicoline. MATERIALS AND METHODS Experimental phase to evaluate the ability of citicoline eye drops to reach the vitreous and the retina: The right eyes of 5 mice CD1 were treated with two drops per day for three days of citicoline 1% and 2% (OMK1, Omikron Italia s.r.l.), and then the vitreous was analyzed with the liquid chromatography and spectrometry mass (LC-MS/MS). Clinical phase to determine if topical citicoline is able to delay glaucoma progression, considering perimetric parameters and electro functional tests. Patients were randomized in two groups, OMK1 and OAG. The first group was treated with OMK1 three times per day, plus hypotensive therapy for two months and one month of wash out. The second group was treated only with hypotensive treatment for three months. RESULTS LC-MS/MS detected the molecule very well, and only OMK1 showed systemic absorption. Thirty-four patients were enrolled, 16 in the OMK1 and 18 in the OAG group. Perimetric parameters showed a positive trend in individual eyes of patients in OMK1 group, but these values were not statistically significant in the whole group. Retinal ganglion cells function improved as shown by reduced P50 latency (P = 0.04) and increased P50-N95 amplitude (P < 0.0001) of pattern electroretinogram, up to 30 days after the washout (P = 0.01; P = 0.002). Visual evoked potential and retino-cortical time improvement regressed after 30 days of washout. In OAG group, there was any change during the follow-up. No adverse reactions were reported in both groups. CONCLUSIONS Topical citicoline seems to have a neuroprotective action.
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Affiliation(s)
- Gloria Roberti
- Istituto di Ricerca e Cura a Carattere Scientifico Fondazione GB Bietti, Via Livenza 3, 00198, Rome, Italy
| | - Lucia Tanga
- Istituto di Ricerca e Cura a Carattere Scientifico Fondazione GB Bietti, Via Livenza 3, 00198, Rome, Italy
| | - Vincenzo Parisi
- Istituto di Ricerca e Cura a Carattere Scientifico Fondazione GB Bietti, Via Livenza 3, 00198, Rome, Italy
| | - Massimo Sampalmieri
- Istituto di Ricerca e Cura a Carattere Scientifico Fondazione GB Bietti, Via Livenza 3, 00198, Rome, Italy
| | - Marco Centofanti
- Istituto di Ricerca e Cura a Carattere Scientifico Fondazione GB Bietti, Via Livenza 3, 00198, Rome, Italy
- Dipartimento di Scienze Cliniche e Medicina Traslazionale, University of Rome Tor Vergata, Viale Oxford 81, 00133, Rome, Italy
| | - Gianluca Manni
- Istituto di Ricerca e Cura a Carattere Scientifico Fondazione GB Bietti, Via Livenza 3, 00198, Rome, Italy
- Dipartimento di Scienze Cliniche e Medicina Traslazionale, University of Rome Tor Vergata, Viale Oxford 81, 00133, Rome, Italy
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Ho LC, Conner IP, Do CW, Kim SG, Wu EX, Wollstein G, Schuman JS, Chan KC. In vivo assessment of aqueous humor dynamics upon chronic ocular hypertension and hypotensive drug treatment using gadolinium-enhanced MRI. Invest Ophthalmol Vis Sci 2014; 55:3747-57. [PMID: 24764067 DOI: 10.1167/iovs.14-14263] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
PURPOSE Although glaucoma treatments alter aqueous humor (AH) dynamics to lower intraocular pressure, the regulatory mechanisms of AH circulation and their contributions to the pathogenesis of ocular hypertension and glaucoma remain unclear. We hypothesized that gadolinium-enhanced magnetic resonance imaging (Gd-MRI) can visualize and assess AH dynamics upon sustained intraocular pressure elevation and pharmacologic interventions. METHODS Gadolinium contrast agent was systemically administered to adult rats to mimic soluble AH components entering the anterior chamber (AC) via blood-aqueous barrier. Dynamic Gd-MRI was applied to examine the signal enhancement in AC and vitreous body upon microbead-induced ocular hypertension and unilateral topical applications of latanoprost, timolol maleate, and brimonidine tartrate to healthy eyes. RESULTS Gadolinium signal time courses in microbead-induced hypertensive eyes possessed faster initial gadolinium uptake and higher peak signals in AC than control eyes, reflective of reduced gadolinium clearance upon microbead occlusion. Opposite trends were observed in latanoprost- and timolol-treated eyes, indicative of their respective drug actions on increased uveoscleral outflow and reduced AH production. The slowest initial gadolinium uptake but strongest peak signals were found in AC of both brimonidine-treated and untreated fellow eyes. These findings drew attention to the systemic effects of topical hypotensive drug treatment. Gadolinium leaked into the vitreous of microbead-induced hypertensive eyes and brimonidine-treated and untreated fellow eyes, suggestive of a compromise of aqueous-vitreous or blood-ocular barrier integrity. CONCLUSIONS Gadolinium-enhanced MRI allows spatiotemporal and quantitative evaluation of altered AH dynamics and ocular tissue permeability for better understanding the physiological mechanisms of ocular hypertension and the efficacy of antiglaucoma drug treatments.
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Affiliation(s)
- Leon C Ho
- NeuroImaging Laboratory, University of Pittsburgh, Pittsburgh, Pennsylvania, United States
| | - Ian P Conner
- UPMC Eye Center, Eye and Ear Institute, Ophthalmology and Visual Science Research Center, Department of Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, United States Department of Bioengineering, Swanson School of Engineering, University of Pittsburgh, Pittsburgh, Pennsylvania, United States Louis J. Fox Center for Vision Restoration, University of Pittsburgh, Pittsburgh, Pennsylvania, United States
| | - Chi-Wai Do
- School of Optometry, The Hong Kong Polytechnic University, Hung Hom, Hong Kong, China
| | - Seong-Gi Kim
- NeuroImaging Laboratory, University of Pittsburgh, Pittsburgh, Pennsylvania, United States UPMC Eye Center, Eye and Ear Institute, Ophthalmology and Visual Science Research Center, Department of Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, United States Department of Bioengineering, Swanson School of Engineering, University of Pittsburgh, Pittsburgh, Pennsylvania, United States McGowan Institute for Regenerative Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania, United States Center for Neuroscience Imaging Research, Institute for Basic Science, Department of Biological Science, Sungkyunkwan University, Suwon, Korea Center for the Neural Basis of Cognition, University of Pittsburgh and Carnegie Mellon University, Pittsburgh, Pennsylvania, United States
| | - Ed X Wu
- Department of Electrical and Electronic Engineering, The University of Hong Kong, Pokfulam, Hong Kong, China
| | - Gadi Wollstein
- UPMC Eye Center, Eye and Ear Institute, Ophthalmology and Visual Science Research Center, Department of Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, United States Louis J. Fox Center for Vision Restoration, University of Pittsburgh, Pittsburgh, Pennsylvania, United States
| | - Joel S Schuman
- UPMC Eye Center, Eye and Ear Institute, Ophthalmology and Visual Science Research Center, Department of Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, United States Department of Bioengineering, Swanson School of Engineering, University of Pittsburgh, Pittsburgh, Pennsylvania, United States McGowan Institute for Regenerative Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania, United States Louis J. Fox Center for Vision Restoration, University of Pittsburgh, Pittsburgh, Pennsylvania, United States
| | - Kevin C Chan
- NeuroImaging Laboratory, University of Pittsburgh, Pittsburgh, Pennsylvania, United States UPMC Eye Center, Eye and Ear Institute, Ophthalmology and Visual Science Research Center, Department of Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, United States Department of Bioengineering, Swanson School of Engineering, University of Pittsburgh, Pittsburgh, Pennsylvania, United States McGowan Institute for Regenerative Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania, United States Louis J. Fox Center for Vision Restoration, University of Pittsburgh, Pittsburgh, Pennsylvania, United States Center for the Neural Basis of Cognition, University of Pittsburgh and Carnegie Mellon University, Pittsburgh, Pennsylvania, United States
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Chan KC, Fan SJ, Chan RW, Cheng JS, Zhou IY, Wu EX. In vivo visuotopic brain mapping with manganese-enhanced MRI and resting-state functional connectivity MRI. Neuroimage 2014; 90:235-45. [PMID: 24394694 PMCID: PMC3951771 DOI: 10.1016/j.neuroimage.2013.12.056] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2013] [Revised: 12/16/2013] [Accepted: 12/23/2013] [Indexed: 12/16/2022] Open
Abstract
The rodents are an increasingly important model for understanding the mechanisms of development, plasticity, functional specialization and disease in the visual system. However, limited tools have been available for assessing the structural and functional connectivity of the visual brain network globally, in vivo and longitudinally. There are also ongoing debates on whether functional brain connectivity directly reflects structural brain connectivity. In this study, we explored the feasibility of manganese-enhanced MRI (MEMRI) via 3 different routes of Mn(2+) administration for visuotopic brain mapping and understanding of physiological transport in normal and visually deprived adult rats. In addition, resting-state functional connectivity MRI (RSfcMRI) was performed to evaluate the intrinsic functional network and structural-functional relationships in the corresponding anatomical visual brain connections traced by MEMRI. Upon intravitreal, subcortical, and intracortical Mn(2+) injection, different topographic and layer-specific Mn enhancement patterns could be revealed in the visual cortex and subcortical visual nuclei along retinal, callosal, cortico-subcortical, transsynaptic and intracortical horizontal connections. Loss of visual input upon monocular enucleation to adult rats appeared to reduce interhemispheric polysynaptic Mn(2+) transfer but not intra- or inter-hemispheric monosynaptic Mn(2+) transport after Mn(2+) injection into visual cortex. In normal adults, both structural and functional connectivity by MEMRI and RSfcMRI was stronger interhemispherically between bilateral primary/secondary visual cortex (V1/V2) transition zones (TZ) than between V1/V2 TZ and other cortical nuclei. Intrahemispherically, structural and functional connectivity was stronger between visual cortex and subcortical visual nuclei than between visual cortex and other subcortical nuclei. The current results demonstrated the sensitivity of MEMRI and RSfcMRI for assessing the neuroarchitecture, neurophysiology and structural-functional relationships of the visual brains in vivo. These may possess great potentials for effective monitoring and understanding of the basic anatomical and functional connections in the visual system during development, plasticity, disease, pharmacological interventions and genetic modifications in future studies.
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Affiliation(s)
- Kevin C Chan
- Laboratory of Biomedical Imaging and Signal Processing, The University of Hong Kong, Pokfulam, Hong Kong SAR, China; Department of Electrical and Electronic Engineering, The University of Hong Kong, Pokfulam, Hong Kong SAR, China; UPMC Eye Center, Ophthalmology and Visual Science Research Center, Louis J. Fox Center for Vision Restoration, Department of Ophthalmology, School of Medicine, University of Pittsburgh, Pittsburgh, PA, USA; Department of Bioengineering, Swanson School of Engineering, University of Pittsburgh, Pittsburgh, PA, USA; Center for the Neural Basis of Cognition, University of Pittsburgh and Carnegie Mellon University, Pittsburgh, PA, USA; McGowan Institute for Regenerative Medicine, University of Pittsburgh, Pittsburgh, PA, USA.
| | - Shu-Juan Fan
- Laboratory of Biomedical Imaging and Signal Processing, The University of Hong Kong, Pokfulam, Hong Kong SAR, China; Department of Electrical and Electronic Engineering, The University of Hong Kong, Pokfulam, Hong Kong SAR, China
| | - Russell W Chan
- Laboratory of Biomedical Imaging and Signal Processing, The University of Hong Kong, Pokfulam, Hong Kong SAR, China; Department of Electrical and Electronic Engineering, The University of Hong Kong, Pokfulam, Hong Kong SAR, China
| | - Joe S Cheng
- Laboratory of Biomedical Imaging and Signal Processing, The University of Hong Kong, Pokfulam, Hong Kong SAR, China; Department of Electrical and Electronic Engineering, The University of Hong Kong, Pokfulam, Hong Kong SAR, China
| | - Iris Y Zhou
- Laboratory of Biomedical Imaging and Signal Processing, The University of Hong Kong, Pokfulam, Hong Kong SAR, China; Department of Electrical and Electronic Engineering, The University of Hong Kong, Pokfulam, Hong Kong SAR, China
| | - Ed X Wu
- Laboratory of Biomedical Imaging and Signal Processing, The University of Hong Kong, Pokfulam, Hong Kong SAR, China; Department of Anatomy, The University of Hong Kong, Pokfulam, Hong Kong SAR, China.
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Cao P, Wu EX. Accelerating phase-encoded proton MR spectroscopic imaging by compressed sensing. J Magn Reson Imaging 2014; 41:487-95. [PMID: 24436225 DOI: 10.1002/jmri.24553] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2013] [Accepted: 12/03/2013] [Indexed: 11/06/2022] Open
Abstract
PURPOSE To develop a phase encoding reduction scheme based on compressed sensing (CS) for phase-encoded (1) H MR spectroscopic imaging (MRSI). MATERIALS AND METHODS Phantom and in vivo rat brain MRSI experiments were performed at 7 Tesla to examine the performance of CS approach and compare it with the full k-space acquisition. The CS undersampling was performed by acquiring a pseudorandom and density-varying subset of phase encodings. Residual water resonance was first removed from the undersampled k-space dataset before CS reconstruction. The CS reconstruction was performed by a linearized Bregman iteration procedure for efficiency in computing large scale L1 minimization. The spectral and spatial fidelity was evaluated by comparing spectral linewidths and metabolite maps and voxel-wise Bland-Altman analysis. RESULTS CS preserved the spectral resolution and metabolite content levels. No spectral broadening was observed, and the estimation biases of the metabolite content levels were no more than 4%. CS clearly preserved the boundaries of metabolite maps but led to slight loss of details in metabolite maps. CONCLUSION This study demonstrated the feasibility of the proposed CS approach to accelerate phase-encoded (1) H MRSI.
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Affiliation(s)
- Peng Cao
- Laboratory of Biomedical Imaging and Signal Processing, The University of Hong Kong, Pokfulam, Hong Kong SAR, China; Department of Electrical and Electronic Engineering, The University of Hong Kong, Pokfulam, Hong Kong SAR, China
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Wu L, Tang Z, Sun X, Feng X, Qian W, Wang J, Jin L. Metabolic changes in the visual cortex of binocular blindness macaque monkeys: a proton magnetic resonance spectroscopy study. PLoS One 2013; 8:e80073. [PMID: 24224037 PMCID: PMC3818303 DOI: 10.1371/journal.pone.0080073] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2013] [Accepted: 10/09/2013] [Indexed: 11/19/2022] Open
Abstract
Purpose To evaluate proton magnetic resonance spectroscopy (1H-MRS) in a study of cross-modal plasticity in the visual cortex of binocular blindness macaque monkeys. Materials and Methods Four healthy neonatal macaque monkeys were randomly divided into 2 groups, with 2 in each group. Optic nerve transection was performed in both monkeys in the experimental group (group B) to obtain binocular blindness. Two healthy macaque monkeys served as a control group (group A). After sixteen months post-procedure, 1H-MRS was performed in the visual cortex of all monkeys. We compared the peak areas of NAA, Cr, Cho, Glx and Ins and the ratios of NAA/Cr, Cho/Cr, Glx/Cr and Ins/Cr of each monkey in group B with group A. Results The peak area of NAA and the NAA/Cr ratio in the visual cortex of monkey 4 in group B were found to be dramatically decreased, the peak area of NAA slightly decreased and the NAA/Cr ratio clearly decreased in visual cortex of monkey 3 in group B than those in group A. The peak area of Ins and the Ins/Cr ratio in the visual cortex of monkey 4 in group B slightly increased. The peak area of Cho and the Cho/Cr ratio in the visual cortex of all monkeys in group B dramatically increased compared with group A. The peak area of Glx in the visual cortex of all monkeys in group B slightly increased compared with group A. Conclusions 1H-MRS could detect biochemical and metabolic changes in the visual cortex and therefore this technique can be used to provide valuable information for investigating the mechanisms of cross-modal plasticity of binocular blindness in a macaque monkey model.
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Affiliation(s)
- Lingjie Wu
- Department of Radiology, Eye and ENT Hospital of Shanghai Medical School, Fudan University, Shanghai, China
| | - Zuohua Tang
- Department of Radiology, Eye and ENT Hospital of Shanghai Medical School, Fudan University, Shanghai, China
- * E-mail: (ZHT); (XHS)
| | - Xinghuai Sun
- Department of Ophthalmology, Eye and ENT Hospital, State Key Laboratory of Medical Neurobiology, Institutes of Brain Science, Fudan University, Shanghai, China
- * E-mail: (ZHT); (XHS)
| | - Xiaoyuan Feng
- Department of Radiology, Huashan Hospital of Shanghai Medical School, Fudan University, Shanghai, China
| | - Wen Qian
- Department of Radiology, Eye and ENT Hospital of Shanghai Medical School, Fudan University, Shanghai, China
| | - Jie Wang
- Department of Radiology, Eye and ENT Hospital of Shanghai Medical School, Fudan University, Shanghai, China
| | - Lixin Jin
- Siemens Ltd. Healthcare Sector, Shanghai, China
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Zhang Y, Chen X, Wen G, Wu G, Zhang X. Proton magnetic resonance spectroscopy ((1)H-MRS) reveals geniculocalcarine and striate area degeneration in primary glaucoma. PLoS One 2013; 8:e73197. [PMID: 24009739 PMCID: PMC3756940 DOI: 10.1371/journal.pone.0073197] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2013] [Accepted: 07/17/2013] [Indexed: 11/18/2022] Open
Abstract
BACKGROUND Glaucoma is a collection of neurodegenerative diseases that affect both the retina and the central visual pathway. We investigated whether metabolites' concentrations changed in the geniculocalcarine (GCT) and the striate area of occipital lobe by proton magnetic resonance spectroscopy ((1)H-MRS), suggesting neurodegeneration of the central visual pathway in primary glaucoma. METHODOLOGY/PRINCIPAL FINDINGS 20 patients with glaucoma in both eyes were paired with 20 healthy volunteers in same gender and an age difference less than 3 years. All the participants were examined by MR imaging including T1 Flair, T2 FSE and (1)H-MRS. The T1 intensity and T2 intensity of their GCTs and striate areas were measured. The ratio of N-acetylaspartate (NAA)/Creatine (Cr), Choline (Cho)/Cr, glutamine and glutamate (Glx)/Cr were derived by multi-voxels (1)H-MRS in the GCT and the striate area of each brain hemisphere. The T1 intensity and T2 intensity had no difference between the groups. Significant decreases in NAA/Cr and Cho/Cr but no difference in Glx/Cr was found between the groups in both the GCT and the striate area. CONCLUSIONS/SIGNIFICANCE Primary glaucoma affects metabolites' concentrations in the GCT and the striate area suggesting there is ongoing neurodegenerative process.
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Affiliation(s)
- Yan Zhang
- Zhongshan Ophthalmic Center, State Key Laboratory of Ophthalmology, Sun Yat-sen University, Guangzhou, GuangDong, China
| | - Xiuyu Chen
- Department of Radiology, Nan Fang Hospital, Southern Medical University, Guangzhou, GuangDong, China
| | - Ge Wen
- Department of Radiology, Nan Fang Hospital, Southern Medical University, Guangzhou, GuangDong, China
| | - Guijun Wu
- Department of Ophthalmology, Nan Fang Hospital, Southern Medical University, Guangzhou, GuangDong, China
| | - Xuelin Zhang
- Department of Radiology, Nan Fang Hospital, Southern Medical University, Guangzhou, GuangDong, China
- * E-mail:
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Neurochemical changes within human early blind occipital cortex. Neuroscience 2013; 252:222-33. [PMID: 23954804 DOI: 10.1016/j.neuroscience.2013.08.004] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2012] [Revised: 08/01/2013] [Accepted: 08/02/2013] [Indexed: 01/01/2023]
Abstract
Early blindness results in occipital cortex neurons responding to a wide range of auditory and tactile stimuli. These changes in tuning properties are accompanied by an extensive reorganization of the occipital cortex that includes alterations in anatomical structure, neurochemical and metabolic pathways. Although it has been established in animal models that neurochemical pathways are heavily affected by early visual deprivation, the effects of blindness on these pathways in humans is still not well characterized. Here, using (1)H magnetic resonance spectroscopy in nine early blind and normally sighted subjects, we find that early blindness is associated with higher levels of creatine, choline and myo-Inositol and indications of lower levels of GABA within the occipital cortex. These results suggest that the cross-modal responses associated with early blindness may, at least in part, be driven by changes within occipital biochemical pathways.
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Chan KC, Wu EX. In vivo manganese-enhanced MRI for visuotopic brain mapping. ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. ANNUAL INTERNATIONAL CONFERENCE 2013; 2012:2279-82. [PMID: 23366378 DOI: 10.1109/embc.2012.6346417] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
This study explored the feasibility of localized manganese-enhanced MRI (MEMRI) via 3 different routes of Mn(2+) administrations for visuotopic brain mapping of retinal, callosal, cortico-subcortical, transsynaptic and horizontal connections in normal adult rats. Upon fractionated intravitreal Mn(2+) injection, Mn enhancements were observed in the contralateral superior colliculus (SC) and lateral geniculate nucleus (LGN) by 45-60% at 1-3 days after initial Mn(2+) injection and in the contralateral primary visual cortex (V1) by about 10% at 2-3 days after initial Mn(2+) injection. Direct, single-dose Mn(2+) injection to the LGN resulted in Mn enhancement by 13-21% in V1 and 8-11% in SC of the ipsilateral hemisphere at 8 to 24 hours after Mn(2+) administration. Intracortical, single-dose Mn(2+) injection to the visual cortex resulted in Mn enhancement by 53-65% in ipsilateral LGN, 15-26% in ipsilateral SC, 32-34% in the splenium of corpus callosum and 17-25% in contralateral V1/V2 transition zone at 8 to 24 hours after Mn(2+) administration. Notably, some patchy patterns were apparent near the V1/V2 border of the contralateral hemisphere. Laminar-specific horizontal cortical connections were also observed in the ipsilateral hemisphere. The current results demonstrated the sensitivity of MEMRI for assessing the neuroarchitecture of the visual brains in vivo without depth-limitation, and may possess great potentials for studying the basic neural components and connections in the visual system longitudinally during development, plasticity, pharmacological interventions and genetic modifications.
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Affiliation(s)
- Kevin C Chan
- Laboratory of Biomedical Imaging and Signal Processing and the Department of Electrical and Electronic Engineering, The University of Hong Kong, Hong Kong SAR, China.
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Duncan RO, Sample PA, Bowd C, Weinreb RN, Zangwill LM. Arterial spin labeling fMRI measurements of decreased blood flow in primary visual cortex correlates with decreased visual function in human glaucoma. Vision Res 2012; 60:51-60. [PMID: 22465941 DOI: 10.1016/j.visres.2012.03.012] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2011] [Revised: 03/17/2012] [Accepted: 03/18/2012] [Indexed: 11/18/2022]
Abstract
PURPOSE Altered metabolic activity has been identified as a potential contributing factor to the neurodegeneration associated with primary open angle glaucoma (POAG). Consequently, we sought to determine whether there is a relationship between the loss of visual function in human glaucoma and resting blood perfusion within primary visual cortex (V1). METHODS Arterial spin labeling (ASL) functional magnetic resonance imaging (fMRI) was conducted in 10 participants with POAG. Resting cerebral blood flow (CBF) was measured from dorsal and ventral V1. Behavioral measurements of visual function were obtained using standard automated perimetry (SAP), short-wavelength automated perimetry (SWAP), and frequency-doubling technology perimetry (FDT). Measurements of CBF were compared to differences in visual function for the superior and inferior hemifield. RESULTS Differences in CBF between ventral and dorsal V1 were correlated with differences in visual function for the superior versus inferior visual field. A statistical bootstrapping analysis indicated that the observed correlations between fMRI responses and measurements of visual function for SAP (r=0.49), SWAP (r=0.63), and FDT (r=0.43) were statistically significant (all p<0.05). CONCLUSIONS Resting blood perfusion in human V1 is correlated with the loss of visual function in POAG. Altered CBF may be a contributing factor to glaucomatous optic neuropathy, or it may be an indication of post-retinal glaucomatous neurodegeneration caused by damage to the retinal ganglion cells.
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Affiliation(s)
- Robert O Duncan
- Department of Behavioral Sciences, The City University of New York, York College, Jamaica, NY 11451, United States.
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Abstract
Food intake can influence neuronal functions through different modulators expressed in the brain. The present review is a report through relevant experimental findings on the effects of choline, a nutritional component found in the diet, to identify a safe and effective dietary solution that can offer some protection against neurotoxicity and neurological disorders and that can be implemented in animals and humans in a very short period of time.
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Affiliation(s)
- Elisabetta Biasi
- Department of Pharmacology and Cancer Biology, Duke Univesity Medical Center, Durham, NC 27710, USA.
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Abstract
Glaucoma is the second leading cause of blindness. It affects retinal ganglion cells and the optic nerve. However, there is emerging evidence that glaucoma also affects other components of the visual pathway and visual cortex. There is a need to employ new methods of in vivo brain evaluation to characterize these changes. Magnetic resonance (MR) techniques are well suited for this purpose. We review data on the MR evaluation of the visual pathway and the use of MR techniques in the study of glaucoma, both in humans and in animal models. These studies demonstrated decreases in optic nerve diameter, localized white matter loss and decrease in visual cortex density. Studies on rats employing manganese-enhanced MRI showed that axonal transport in the optic nerve is affected. Diffusion tensor MRI revealed signs of degeneration of the optic pathway. Functional MRI showed decreased response of the visual cortex after stimulation of the glaucomatous eye. Magnetic resonance spectroscopy demonstrated changes in metabolite levels in the visual cortex in a rat model of glaucoma, although not in glaucoma patients. Further applications of MR techniques in studies of glaucomatous brains are indicated.
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Affiliation(s)
- Michal Fiedorowicz
- Department of Experimental Pharmacology, Polish Academy of Science Medical Research Centre, Warsaw, Poland.
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Learning and memory alterations are associated with hippocampal N-acetylaspartate in a rat model of depression as measured by 1H-MRS. PLoS One 2011; 6:e28686. [PMID: 22194886 PMCID: PMC3237477 DOI: 10.1371/journal.pone.0028686] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2011] [Accepted: 11/13/2011] [Indexed: 11/25/2022] Open
Abstract
It is generally accepted that cognitive processes, such as learning and memory, are affected in depression. The present study used a rat model of depression, chronic unpredictable mild stress (CUMS), to determine whether hippocampal volume and neurochemical changes were involved in learning and memory alterations. A further aim was to determine whether these effects could be ameliorated by escitalopram treatment, as assessed with the non-invasive techniques of structural magnetic resonance imaging (MRI) and magnetic resonance spectroscopy (MRS). Our results demonstrated that CUMS had a dramatic influence on spatial cognitive performance in the Morris water maze task, and CUMS reduced the concentration of neuronal marker N-acetylaspartate (NAA) in the hippocampus. These effects could be significantly reversed by repeated administration of escitalopram. However, neither chronic stress nor escitalopram treatment influenced hippocampal volume. Of note, the learning and memory alterations of the rats were associated with right hippocampal NAA concentration. Our results indicate that in depression, NAA may be a more sensitive measure of cognitive function than hippocampal volume.
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Xiao L, Wu EX. Diffusion-weighted magnetic resonance spectroscopy: A novel approach to investigate intramyocellular lipids. Magn Reson Med 2011; 66:937-44. [DOI: 10.1002/mrm.23121] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
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Retinal metabolic changes in an experimental model of optic nerve transection by ex vivo 1H magnetic resonance spectroscopy. Neurochem Res 2011; 36:2427-33. [PMID: 21842271 DOI: 10.1007/s11064-011-0570-7] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2011] [Revised: 07/26/2011] [Accepted: 08/02/2011] [Indexed: 10/17/2022]
Abstract
This study aims to investigate the retinal metabolic processes in a rat axotomy model. Retinal metabolic changes in optic nerve transection (ONT) rat model were analyzed by (1)H magnetic resonance spectroscopy ((1)H-MRS). Retinal ganglion cells (RGCs) densities were assessed from retinal whole mounts. The retina was stained immunohistochemically with glial fibrillary acidic protein (GFAP). The results showed that the retina in ONT rats had significantly decreased concentrations of γ-aminobutyric acid (GABA), N-acetylaspartate (NAA), taurine (Tau), creatine (Cr) and increased concentrations of alanine (Ala) compared with control. Examination of glutamate (Glu), glutamine (Gln) and Glx (Glu + Gln) concentrations disclosed no significant differences. The mean density of RGCs reduced from 2,249 ± 87 cells/mm(2) in control group to 320 ± 56 cells/mm(2) in ONT group. GFAP immunoreactivity was markedly higher in ONT group than that in control group. The retinal metabolism after ONT was associated with neurotransmitter recycling/production perturbation, as well as other metabolic disequilibrium.
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Lau C, Zhou IY, Cheung MM, Chan KC, Wu EX. BOLD temporal dynamics of rat superior colliculus and lateral geniculate nucleus following short duration visual stimulation. PLoS One 2011; 6:e18914. [PMID: 21559482 PMCID: PMC3084720 DOI: 10.1371/journal.pone.0018914] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2010] [Accepted: 03/24/2011] [Indexed: 11/26/2022] Open
Abstract
BACKGROUND The superior colliculus (SC) and lateral geniculate nucleus (LGN) are important subcortical structures for vision. Much of our understanding of vision was obtained using invasive and small field of view (FOV) techniques. In this study, we use non-invasive, large FOV blood oxygenation level-dependent (BOLD) fMRI to measure the SC and LGN's response temporal dynamics following short duration (1 s) visual stimulation. METHODOLOGY/PRINCIPAL FINDINGS Experiments are performed at 7 tesla on Sprague Dawley rats stimulated in one eye with flashing light. Gradient-echo and spin-echo sequences are used to provide complementary information. An anatomical image is acquired from one rat after injection of monocrystalline iron oxide nanoparticles (MION), a blood vessel contrast agent. BOLD responses are concentrated in the contralateral SC and LGN. The SC BOLD signal measured with gradient-echo rises to 50% of maximum amplitude (PEAK) 0.2±0.2 s before the LGN signal (p<0.05). The LGN signal returns to 50% of PEAK 1.4±1.2 s before the SC signal (p<0.05). These results indicate the SC signal rises faster than the LGN signal but settles slower. Spin-echo results support these findings. The post-MION image shows the SC and LGN lie beneath large blood vessels. This subcortical vasculature is similar to that in the cortex, which also lies beneath large vessels. The LGN lies closer to the large vessels than much of the SC. CONCLUSIONS/SIGNIFICANCE The differences in response timing between SC and LGN are very similar to those between deep and shallow cortical layers following electrical stimulation, which are related to depth-dependent blood vessel dilation rates. This combined with the similarities in vasculature between subcortex and cortex suggest the SC and LGN timing differences are also related to depth-dependent dilation rates. This study shows for the first time that BOLD responses in the rat SC and LGN following short duration visual stimulation are temporally different.
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Affiliation(s)
- Condon Lau
- Laboratory of Biomedical Imaging and Signal Processing, The University of Hong Kong, Pokfulam, Hong Kong, Special Administrative Region, China
- Department of Electrical and Electronic Engineering, The University of Hong Kong, Pokfulam, Hong Kong, Special Administrative Region, China
| | - Iris Y. Zhou
- Laboratory of Biomedical Imaging and Signal Processing, The University of Hong Kong, Pokfulam, Hong Kong, Special Administrative Region, China
- Department of Electrical and Electronic Engineering, The University of Hong Kong, Pokfulam, Hong Kong, Special Administrative Region, China
| | - Matthew M. Cheung
- Laboratory of Biomedical Imaging and Signal Processing, The University of Hong Kong, Pokfulam, Hong Kong, Special Administrative Region, China
- Department of Electrical and Electronic Engineering, The University of Hong Kong, Pokfulam, Hong Kong, Special Administrative Region, China
| | - Kevin C. Chan
- Laboratory of Biomedical Imaging and Signal Processing, The University of Hong Kong, Pokfulam, Hong Kong, Special Administrative Region, China
- Department of Electrical and Electronic Engineering, The University of Hong Kong, Pokfulam, Hong Kong, Special Administrative Region, China
| | - Ed X. Wu
- Laboratory of Biomedical Imaging and Signal Processing, The University of Hong Kong, Pokfulam, Hong Kong, Special Administrative Region, China
- Department of Electrical and Electronic Engineering, The University of Hong Kong, Pokfulam, Hong Kong, Special Administrative Region, China
- Department of Anatomy, The University of Hong Kong, Pokfulam, Hong Kong, Special Administrative Region, China
- Department of Medicine, The University of Hong Kong, Pokfulam, Hong Kong, Special Administrative Region, China
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Cheung JS, Fan SJ, Gao DS, Chow AM, Yang J, Man K, Wu EX. In vivo lipid profiling using proton magnetic resonance spectroscopy in an experimental liver fibrosis model. Acad Radiol 2011; 18:377-83. [PMID: 21167757 DOI: 10.1016/j.acra.2010.10.012] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2010] [Revised: 10/27/2010] [Accepted: 10/29/2010] [Indexed: 12/19/2022]
Abstract
RATIONALE AND OBJECTIVES The aim of this study was to characterize early hepatic lipid changes in an experimental model of liver fibrosis using proton ((1)H) magnetic resonance spectroscopy (MRS) at high magnetic field in vivo. MATERIALS AND METHODS Liver fibrosis was induced in 12 Sprague-Dawley rats by twice-weekly carbon tetrachloride (CCl(4)) administration up to 4 weeks. Eight normal rats were used as controls. Single-voxel (1)H MRS experiments were performed at 7 Tesla to measure signal integrals of various lipid peaks including -CH(3), (-CH(2)-)(n), -CH(2)-C=C-CH(2)-, =C-CH(2)-C= and -CH=CH- at 0.9, 1.3, 2.0, 2.8, and 5.3 ppm, respectively, and peak from choline-containing compounds (CCC) at 3.2 ppm. Total lipid, total saturated fatty acid, total unsaturated fatty acid, total unsaturated bond, polyunsaturated bond, and CCC indices were quantified. RESULTS Significant increases (P < .01) in total lipid and total saturated fatty acid indices were found in animals with CCl(4)-induced fibrosis as compared with normal animals. In addition, total unsaturated bond and polyunsaturated bond indices of animals at 4 weeks after CCl(4) insult were significantly higher than (P < .01 and P < .05, respectively) those of normal animals and animals at 2 weeks following insult; whereas there was only significant increase (P < .01) in total unsaturated fatty acid index in animals with 4-week CCl(4) insult as compared with normal animals. CONCLUSION The hepatic lipid changes in CCl(4)-induced experimental fibrosis model were documented in vivo and longitudinally using (1)H MRS at 7 Tesla. The experimental findings suggested that total saturated fatty acid increase contributed mainly to the total lipid increase in animals with CCl(4) insult. This study also demonstrated the potential value of high field MRS to resolve lipid composition and alterations in liver fibrosis.
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Chow AM, Chan KW, Fan SJ, Yang J, Cheung JS, Khong PL, Wu EX. In vivo proton magnetic resonance spectroscopy of hepatic ischemia/reperfusion injury in an experimental model. Acad Radiol 2011; 18:246-52. [PMID: 21111640 DOI: 10.1016/j.acra.2010.09.019] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2010] [Revised: 06/02/2010] [Accepted: 09/20/2010] [Indexed: 01/03/2023]
Abstract
RATIONALE AND OBJECTIVES Hepatic ischemia/reperfusion injury (IRI) occurs during certain hepatobiliary surgeries, hemorrhagic shock, and veno-occlusive disease. Biochemical changes caused by hepatic IRI lead to hepatocellular remodeling, including cellular regeneration or irreversible apoptosis. This study aims to characterize and monitor the metabolic changes in hepatic IRI using proton magnetic resonance spectroscopy (¹H MRS). MATERIALS AND METHODS Sprague-Dawley rats (n = 8) were scanned with ¹H MRS using 5.0 × 5.0 × 5.0 mm³ voxel over a homogeneous liver parenchyma at 7 Tesla with a respiratory-gated point-resolved spectroscopy sequence at 1 day before, 6 hours, 1 day, and 1 week after 30 minutes total hepatic IRI. Signal integral ratios of choline-containing compounds (CCC), glycogen and glucose complex (Glyu), methylene proton ((-CH₂-)(n)), and methene proton (-CH=CH-) to lipid (integral sum of methyl proton (-CH₃), (-CH₂-)(n) and -CH=CH-) were quantified by areas under peaks longitudinally. RESULTS The CCC-to-lipid and Glyu-to-lipid ratios at 6 hours after IRI were significantly higher than those at 1 day before, 1 day, and 1 week after injury. The (-CH₂-)(n)-to-lipid, and -CH=CH-to-lipid ratios showed no significant differences over different time points. Hepatocellular regeneration was observed at 6 hours after IRI in histology with immunohistochemical technique. CONCLUSIONS Changes in CCC-to-lipid and Glyu-to-lipid ratios likely reflect the hepatocellular remodeling and impaired glucose utilization upon hepatic IRI, respectively. The experimental findings in the current study demonstrated that ¹H MRS is a valuable tool for characterizing either global or regional metabolic changes in liver noninvasively and longitudinally. Such capability has the potential to lead to early diagnosis and detection of impaired liver function.
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CHAN KEVINC, CHEUNG MATTHEWM, WU EDX. IN VIVOMULTIPARAMETRIC MAGNETIC RESONANCE IMAGING AND SPECTROSCOPY OF RODENT VISUAL SYSTEM. J Integr Neurosci 2010; 9:477-508. [DOI: 10.1142/s0219635210002524] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2010] [Accepted: 11/04/2010] [Indexed: 01/27/2023] Open
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Chan KC, Cheung MM, Xing KK, Zhou IY, Chow AM, Lau C, So KF, Wu EX. In vivo MRI study of the visual system in normal, developing and injured rodent brains. ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. ANNUAL INTERNATIONAL CONFERENCE 2010; 2010:5689-92. [PMID: 21097319 DOI: 10.1109/iembs.2010.5627884] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
This paper demonstrated our recent use of contrast-enhanced MRI, diffusion tensor/kurtosis imaging, proton magnetic resonance spectroscopy, and functional MRI techniques, for in vivo and global assessments of the structure, metabolism and function of the visual system in rodent studies of ocular diseases, optic neuropathies, developmental plasticity and neonatal hypoxic-ischemic brain injury at 7T. Results suggested the significant values of high-field multiparametric MRI for uncovering the processes and mechanisms of developmental and pathophysiological changes systematically along both anterior and posterior visual pathways, and may provide early diagnoses and therapeutic strategies for promoting functional recovery upon partial vision loss.
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Affiliation(s)
- Kevin C Chan
- Laboratory of Biomedical Imaging and Signal Processing and the Department of Electrical and Electronic Engineering, The University of Hong Kong, Pokfulam, Hong Kong.
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Chow AM, Zhou IY, Fan SJ, Chan KW, Chan KC, Wu EX. Metabolic changes in visual cortex of neonatal monocular enucleated rat: a proton magnetic resonance spectroscopy study. Int J Dev Neurosci 2010; 29:25-30. [DOI: 10.1016/j.ijdevneu.2010.10.002] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2010] [Revised: 08/30/2010] [Accepted: 10/01/2010] [Indexed: 01/14/2023] Open
Affiliation(s)
- April M. Chow
- Laboratory of Biomedical Imaging and Signal ProcessingThe University of Hong KongPokfulamHong Kong SARChina
- Department of Electrical and Electronic EngineeringThe University of Hong KongPokfulamHong Kong SARChina
| | - Iris Y. Zhou
- Laboratory of Biomedical Imaging and Signal ProcessingThe University of Hong KongPokfulamHong Kong SARChina
- Department of Electrical and Electronic EngineeringThe University of Hong KongPokfulamHong Kong SARChina
| | - Shu Juan Fan
- Laboratory of Biomedical Imaging and Signal ProcessingThe University of Hong KongPokfulamHong Kong SARChina
- Department of Electrical and Electronic EngineeringThe University of Hong KongPokfulamHong Kong SARChina
| | - Kannie W.Y. Chan
- Laboratory of Biomedical Imaging and Signal ProcessingThe University of Hong KongPokfulamHong Kong SARChina
- Department of Electrical and Electronic EngineeringThe University of Hong KongPokfulamHong Kong SARChina
| | - Kevin C. Chan
- Laboratory of Biomedical Imaging and Signal ProcessingThe University of Hong KongPokfulamHong Kong SARChina
- Department of Electrical and Electronic EngineeringThe University of Hong KongPokfulamHong Kong SARChina
| | - Ed X. Wu
- Laboratory of Biomedical Imaging and Signal ProcessingThe University of Hong KongPokfulamHong Kong SARChina
- Department of Electrical and Electronic EngineeringThe University of Hong KongPokfulamHong Kong SARChina
- Department of AnatomyThe University of Hong KongPokfulamHong Kong SARChina
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