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LA-ICP-MS bioimaging demonstrated disturbance of metal ions in the brain of Parkinson's disease model mouse undergoing manganese-enhanced MRI. Anal Bioanal Chem 2022; 414:5561-5571. [PMID: 35275218 DOI: 10.1007/s00216-022-03994-9] [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: 12/24/2021] [Revised: 02/10/2022] [Accepted: 02/25/2022] [Indexed: 11/01/2022]
Abstract
Manganese-enhanced MRI (MEMRI) is a powerful tool to study neuronal activity and microarchitecture in vivo. Yet the influence of exogenous manganese on the brain of the Parkinson's disease (PD) model mouse is poorly understood. Laser ablation connected to inductively coupled plasma mass spectrometry (LA-ICP-MS) imaging for tissue section is an ideal tool to simultaneously analyze the metabolism of endogenous metal ions. In this study, DJ-1 knockout PD model mice were subjected to an MnCl2 saline treatment and the distribution of Mn and several other endogenous metal ions in brain regions was assessed by MEMRI and LA-ICP-MS imaging. The results demonstrated that Mn mainly deposited in subcortical regions, such as ventricles, hippocampus (HC), medial preoptic nucleus (MPO), lateral septal nucleus (LS), and ventromedial hypothalamic nucleus (VMH). The enhanced signal-to-noise ratio (S/N) determined by MEMRI for Mn is closely related to the signal in LA-ICP-MS imaging. Significantly, the treatment of MnCl2 disturbs the homeostasis of iron, zinc, copper, and calcium in the DJ-1 mouse, which could result in more severe symptoms of PD. Therefore, the application of MEMRI in the study of neurological disease must be made with caution.
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Komatsu C, van der Merwe Y, He L, Kasi A, Sims JR, Miller MR, Rosner IA, Khatter NJ, Su AJA, Schuman JS, Washington KM, Chan KC. In vivo MRI evaluation of anterograde manganese transport along the visual pathway following whole eye transplantation. J Neurosci Methods 2022; 372:109534. [PMID: 35202613 PMCID: PMC8940646 DOI: 10.1016/j.jneumeth.2022.109534] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2021] [Revised: 02/12/2022] [Accepted: 02/18/2022] [Indexed: 11/17/2022]
Abstract
BACKGROUND Since adult mammalian retinal ganglion cells cannot regenerate after injury, we have recently established a whole-eye transplantation (WET) rat model that provides an intact optical system to investigate potential surgical restoration of irreversible vision loss. However, it remains to be elucidated whether physiological axoplasmic transport exists in the transplanted visual pathway. New Method: We developed an in vivo imaging model system to assess WET integration using manganese-enhanced magnetic resonance imaging (MEMRI) in rats. Since Mn2+ is a calcium analogue and an active T1-positive contrast agent, the levels of anterograde manganese transport can be evaluated in the visual pathways upon intravitreal Mn2+ administration into both native and transplanted eyes. RESULTS No significant intraocular pressure difference was found between native and transplanted eyes, whereas comparable manganese enhancement was observed between native and transplanted intraorbital optic nerves, suggesting the presence of anterograde manganese transport after WET. No enhancement was detected across the coaptation site in the higher visual areas of the recipient brain. Comparison with Existing Methods: Existing imaging methods to assess WET focus on either the eye or local optic nerve segments without direct visualization and longitudinal quantification of physiological transport along the transplanted visual pathway, hence the development of in vivo MEMRI. CONCLUSION Our established imaging platform indicated that essential physiological transport exists in the transplanted optic nerve after WET. As neuroregenerative approaches are being developed to connect the transplanted eye to the recipient's brain, in vivo MEMRI is well-suited to guide strategies for successful WET integration for vision restoration. Keywords (Max 6): Anterograde transport, magnetic resonance imaging, manganese, neuroregeneration, optic nerve, whole-eye transplantation.
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Affiliation(s)
- Chiaki Komatsu
- Department of Plastic and Reconstructive Surgery, Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA, United States
| | - Yolandi van der Merwe
- Department of Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh, PA, United States
| | - Lin He
- Department of Plastic and Reconstructive Surgery, Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA, United States; Department of Plastic, Aesthetic & Maxillofacial Surgery, the First Affiliated Hospital of Xi'an Jiaotong University, Xi'an, Shaanxi, China
| | - Anisha Kasi
- Department of Ophthalmology, NYU Grossman School of Medicine, NYU Langone Health, New York University, New York, NY, United States
| | - Jeffrey R Sims
- Department of Ophthalmology, NYU Grossman School of Medicine, NYU Langone Health, New York University, New York, NY, United States
| | - Maxine R Miller
- Department of Plastic and Reconstructive Surgery, Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA, United States; Department of Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh, PA, United States
| | - Ian A Rosner
- Department of Plastic and Reconstructive Surgery, Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA, United States
| | - Neil J Khatter
- Division of Plastic and Reconstructive Surgery, Department of Surgery, University of Colorado, Denver, CO, United States; William Beaumont School of Medicine, Oakland University, Rochester, MI, United States
| | - An-Jey A Su
- Department of Plastic and Reconstructive Surgery, Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA, United States; Division of Plastic and Reconstructive Surgery, Department of Surgery, University of Colorado, Denver, CO, United States
| | - Joel S Schuman
- Department of Ophthalmology, NYU Grossman School of Medicine, NYU Langone Health, New York University, New York, NY, United States; Neuroscience Institute, NYU Grossman School of Medicine, NYU Langone Health, New York University, New York, NY, United States; Center for Neural Science, College of Arts and Science, New York University, New York, NY, United States; Department of Biomedical Engineering, Tandon School of Engineering, New York University, New York, NY, United States
| | - Kia M Washington
- Department of Plastic and Reconstructive Surgery, Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA, United States; Department of Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh, PA, United States; Division of Plastic and Reconstructive Surgery, Department of Surgery, University of Colorado, Denver, CO, United States; Veterans Administration Pittsburgh Healthcare System, Pittsburgh, PA, United States
| | - Kevin C Chan
- Department of Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh, PA, United States; Department of Ophthalmology, NYU Grossman School of Medicine, NYU Langone Health, New York University, New York, NY, United States; Neuroscience Institute, NYU Grossman School of Medicine, NYU Langone Health, New York University, New York, NY, United States; Center for Neural Science, College of Arts and Science, New York University, New York, NY, United States; Department of Biomedical Engineering, Tandon School of Engineering, New York University, New York, NY, United States; Department of Radiology, NYU Grossman School of Medicine, NYU Langone Health, New York University, New York, NY, United States.
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Becq GJPC, Habet T, Collomb N, Faucher M, Delon-Martin C, Coizet V, Achard S, Barbier EL. Functional connectivity is preserved but reorganized across several anesthetic regimes. Neuroimage 2020; 219:116945. [DOI: 10.1016/j.neuroimage.2020.116945] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2019] [Revised: 04/21/2020] [Accepted: 05/11/2020] [Indexed: 12/12/2022] Open
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4
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Malheiros JM, Andreeta MB, Polli RS, Paiva FF, Tannús A, Guinsburg R, Covolan L. Adult brain activation in response to pain is changed by neonatal painful stimulation according to sex: A manganese-enhanced MRI study. Eur J Neurosci 2020; 53:571-587. [PMID: 32852090 DOI: 10.1111/ejn.14948] [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: 09/02/2019] [Revised: 07/27/2020] [Accepted: 08/13/2020] [Indexed: 11/30/2022]
Abstract
Although it is known that nociceptive stimulation in the first postnatal week in rats is useful to model preterm pain, resulting in activation of specific brain areas, as assessed in vivo using manganese-enhanced magnetic resonance imaging (MEMRI), little is known about its long-term effects and sex specificity. Here we aimed to investigate whether inflammatory pain induced in male and female adult rats modify the pattern of brain activation between animals subjected or not to neonatal pain. For this, Complete Freund's adjuvant (CFA) was injected into the left hind paw of rat pups on postnatal day 1 (P1) or P8 to induce inflammatory response. During adulthood, CFA-treated and control animals were injected with CFA 1 hr prior MRI. MEMRI has the ability to enhance the contrast of selective brain structures in response to a specific stimulus, as the pain. MEMRI responses were consistent with activation of nociceptive pathways and these responses were reduced in animals treated with CFA on P1, but increased in animals treated on P8, mainly in the female group. In agreement, P8 female group showed exacerbated responses in the thermal nociceptive test. Using MEMRI, we conclude that the natural ability of adult rats to recognize and react to pain exposition is modified by neonatal painful exposition, mainly among females.
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Affiliation(s)
| | - Mariane B Andreeta
- Instituto de Física de São Carlos, Universidade de São Paulo, São Carlos, Brazil
| | - Roberson S Polli
- Instituto de Ciência e Tecnologia, Universidade Federal de São Paulo, São José dos Campos, Brazil
| | - Fernando F Paiva
- Centro de Imagens e Espectroscopia in vivo por Ressonância Magnética (CIERMag), Instituto de Física de São Carlos, Universidade de São Paulo, São Carlos, Brazil
| | - Alberto Tannús
- Centro de Imagens e Espectroscopia in vivo por Ressonância Magnética (CIERMag), Instituto de Física de São Carlos, Universidade de São Paulo, São Carlos, Brazil
| | - Ruth Guinsburg
- Disciplina de Pediatria Neonatal, Departamento de Pediatria, Universidade Federal de São Paulo, São Paulo, Brazil
| | - Luciene Covolan
- Departamento de Fisiologia, Universidade Federal de São Paulo, São Paulo, Brazil
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5
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Xiao Z, Tang Z, Wu L, Feng X, Sun X, Tang W, Wang J, Jin L, Wang R. Manganese-enhanced magnetic resonance imaging in the whole visual pathway: chemical identification and neurotoxic changes. Acta Radiol 2019; 60:1653-1662. [PMID: 30922072 DOI: 10.1177/0284185119840227] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Affiliation(s)
- Zebin Xiao
- Department of Radiology, Eye & ENT Hospital of Shanghai Medical School, Fudan University, Shanghai, PR China
| | - Zuohua Tang
- Department of Radiology, Eye & ENT Hospital of Shanghai Medical School, Fudan University, Shanghai, PR China
| | - Lingjie Wu
- Department of Otolaryngology, Eye & ENT Hospital of Shanghai Medical School, Fudan University, Shanghai, PR China
| | - Xiaoyuan Feng
- Department of Radiology, Huashan Hospital of Shanghai Medical School, Fudan University, Shanghai, PR China
| | - Xinghuai Sun
- Department of Ophthalmology & Visual Science, Eye & ENT Hospital of Shanghai Medical School, State Key Laboratory of Medical Neurobiology, Institutes of Brain Science, Fudan University, Key Laboratory of Myopia, NHFPC (Fudan University), and Shanghai Key Laboratory of Visual Impairment and Restoration, Fudan University, Shanghai, PR China
| | - Weijun Tang
- Department of Radiology, Huashan Hospital of Shanghai Medical School, Fudan University, Shanghai, PR China
| | - Jie Wang
- Department of Radiotherapy, Eye & ENT Hospital of Shanghai Medical School, Fudan University, Shanghai, PR China
| | - Lixin Jin
- Siemens Ltd., Healthcare Sector, Shanghai, PR China
| | - Rong Wang
- Department of Radiology, Eye & ENT Hospital of Shanghai Medical School, Fudan University, Shanghai, PR China
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6
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Dong CM, Leong ATL, Manno FA, Lau C, Ho LC, Chan RW, Feng Y, Gao PP, Wu EX. Functional MRI Investigation of Audiovisual Interactions in Auditory Midbrain. ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. ANNUAL INTERNATIONAL CONFERENCE 2019; 2018:5527-5530. [PMID: 30441589 DOI: 10.1109/embc.2018.8513629] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
The brain integrates information from different sensory modalities to form a representation of the environment and facilitate behavioral responses. The auditory midbrain or inferior colliculus (IC) is a pivotal station in the auditory system, integrating ascending and descending information from various auditory sources and cortical systems. The present study investigated the modulation of auditory responses in the IC by visual stimuli of different frequencies and intensities in rats using functional MRI (fMRI). Low-frequency (1 Hz) high-intensity visual stimulus suppressed IC auditory responses. However, high-frequency (10 Hz) or low-intensity visual stimuli did not alter the IC auditory responses. This finding demonstrates that cross-modal processing occurs in the IC in a manner that depends on the stimulus. Furthermore, only low-frequency high-intensity visual stimulus elicited responses in non-visual cortical regions, suggesting that the above cross-modal modulation effect may arise from top-down cortical feedback. These fMRI results provide insight to guide future studies of cross-modal processing in sensory pathways.
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7
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Deng W, Faiq MA, Liu C, Adi V, Chan KC. Applications of Manganese-Enhanced Magnetic Resonance Imaging in Ophthalmology and Visual Neuroscience. Front Neural Circuits 2019; 13:35. [PMID: 31156399 PMCID: PMC6530364 DOI: 10.3389/fncir.2019.00035] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2019] [Accepted: 04/26/2019] [Indexed: 12/21/2022] Open
Abstract
Understanding the mechanisms of vision in health and disease requires knowledge of the anatomy and physiology of the eye and the neural pathways relevant to visual perception. As such, development of imaging techniques for the visual system is crucial for unveiling the neural basis of visual function or impairment. Magnetic resonance imaging (MRI) offers non-invasive probing of the structure and function of the neural circuits without depth limitation, and can help identify abnormalities in brain tissues in vivo. Among the advanced MRI techniques, manganese-enhanced MRI (MEMRI) involves the use of active manganese contrast agents that positively enhance brain tissue signals in T1-weighted imaging with respect to the levels of connectivity and activity. Depending on the routes of administration, accumulation of manganese ions in the eye and the visual pathways can be attributed to systemic distribution or their local transport across axons in an anterograde fashion, entering the neurons through voltage-gated calcium channels. The use of the paramagnetic manganese contrast in MRI has a wide range of applications in the visual system from imaging neurodevelopment to assessing and monitoring neurodegeneration, neuroplasticity, neuroprotection, and neuroregeneration. In this review, we present four major domains of scientific inquiry where MEMRI can be put to imperative use — deciphering neuroarchitecture, tracing neuronal tracts, detecting neuronal activity, and identifying or differentiating glial activity. We deliberate upon each category studies that have successfully employed MEMRI to examine the visual system, including the delivery protocols, spatiotemporal characteristics, and biophysical interpretation. Based on this literature, we have identified some critical challenges in the field in terms of toxicity, and sensitivity and specificity of manganese enhancement. We also discuss the pitfalls and alternatives of MEMRI which will provide new avenues to explore in the future.
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Affiliation(s)
- Wenyu Deng
- NYU Langone Eye Center, Department of Ophthalmology, NYU School of Medicine, NYU Langone Health, New York University, New York, NY, United States
| | - Muneeb A Faiq
- NYU Langone Eye Center, Department of Ophthalmology, NYU School of Medicine, NYU Langone Health, New York University, New York, NY, United States
| | - Crystal Liu
- NYU Langone Eye Center, Department of Ophthalmology, NYU School of Medicine, NYU Langone Health, New York University, New York, NY, United States
| | - Vishnu Adi
- NYU Langone Eye Center, Department of Ophthalmology, NYU School of Medicine, NYU Langone Health, New York University, New York, NY, United States
| | - Kevin C Chan
- NYU Langone Eye Center, Department of Ophthalmology, NYU School of Medicine, NYU Langone Health, New York University, New York, NY, United States.,Department of Radiology, NYU School of Medicine, NYU Langone Health, New York University, 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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8
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Evaluation of nuisance removal for functional MRI of rodent brain. Neuroimage 2019; 188:694-709. [DOI: 10.1016/j.neuroimage.2018.12.048] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2018] [Revised: 12/12/2018] [Accepted: 12/22/2018] [Indexed: 12/17/2022] Open
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9
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Cloyd RA, Koren SA, Abisambra JF. Manganese-Enhanced Magnetic Resonance Imaging: Overview and Central Nervous System Applications With a Focus on Neurodegeneration. Front Aging Neurosci 2018; 10:403. [PMID: 30618710 PMCID: PMC6300587 DOI: 10.3389/fnagi.2018.00403] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2018] [Accepted: 11/23/2018] [Indexed: 12/16/2022] Open
Abstract
Manganese-enhanced magnetic resonance imaging (MEMRI) rose to prominence in the 1990s as a sensitive approach to high contrast imaging. Following the discovery of manganese conductance through calcium-permeable channels, MEMRI applications expanded to include functional imaging in the central nervous system (CNS) and other body systems. MEMRI has since been employed in the investigation of physiology in many animal models and in humans. Here, we review historical perspectives that follow the evolution of applied MRI research into MEMRI with particular focus on its potential toxicity. Furthermore, we discuss the more current in vivo investigative uses of MEMRI in CNS investigations and the brief but decorated clinical usage of chelated manganese compound mangafodipir in humans.
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Affiliation(s)
- Ryan A Cloyd
- Department of Physiology, University of Kentucky, Lexington, KY, United States.,College of Medicine, University of Kentucky, Lexington, KY, United States.,Sanders-Brown Center on Aging, University of Kentucky, Lexington, KY, United States
| | - Shon A Koren
- Department of Physiology, University of Kentucky, Lexington, KY, United States.,Sanders-Brown Center on Aging, University of Kentucky, Lexington, KY, United States.,Department of Neuroscience & Center for Translational Research in Neurodegenerative Disease, University of Florida, Gainesville, FL, United States
| | - Jose F Abisambra
- Department of Physiology, University of Kentucky, Lexington, KY, United States.,Sanders-Brown Center on Aging, University of Kentucky, Lexington, KY, United States.,Department of Neuroscience & Center for Translational Research in Neurodegenerative Disease, University of Florida, Gainesville, FL, United States.,Spinal Cord and Brain Injury Research Center, University of Kentucky, Lexington, KY, United States
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10
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Sato C, Sawada K, Wright D, Higashi T, Aoki I. Isotropic 25-Micron 3D Neuroimaging Using ex vivo Microstructural Manganese-Enhanced MRI (MEMRI). Front Neural Circuits 2018; 12:110. [PMID: 30574072 PMCID: PMC6291442 DOI: 10.3389/fncir.2018.00110] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2018] [Accepted: 11/23/2018] [Indexed: 12/27/2022] Open
Abstract
MRI observations following in vivo administration of Mn2+ [manganese (Mn)-enhanced MRI, MEMRI] have been used as an excellent morphological and functional MRI tool for in vivo preclinical studies. To detect brain three-dimensional (3D) microstructures, we improved the ex vivo MEMRI method for mouse brains after in vivo Mn administration and obtained high-resolution MRIs using a cryogenic radiofrequency (RF) coil. Male C57BL/6 mice (n = 8) were injected with 50 mM MnCl2 intravenously and MEMRIs of the brain were acquired in vivo after 24 h, followed by perfusion fixation with a 4% paraformaldehyde (PFA) solution. High-resolution 25-μm isotropic MRIs were successfully acquired from the extracted brain tissue and could identify the brain microstructures, especially in the hippocampus [the pyramidal cell layer through CA1–3 and the dentate gyrus (DG) granular layers (GLs)], cell layers of cerebellum, three sub-regions of the deep cerebellar nucleus, and white matter (WM) structures [e.g., the fasciculus retroflexus (fr) and optic tract in the thalamus]. The following technical conditions were also examined: (i) the longitudinal stability of Mn-enhanced ex vivo tissue after in vivo administration; and (ii) the effects of mixing glutaraldehyde (GA) with the fixative solution for the preservation of in vivo MEMRI contrast. Our results indicate that ex vivo MEMRI observations made shortly after fixation maintain the contrast observed in vivo. This research will be useful for non-destructive whole-brain pathological analysis.
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Affiliation(s)
- Chika Sato
- Department of Molecular Imaging and Theranostics, National Institute of Radiological Sciences, National Institutes for Quantum and Radiological Science and Technology (QST), Chiba, Japan.,Group of Quantum-State Controlled MRI, QST, Chiba, Japan
| | - Kazuhiko Sawada
- Department of Nutrition, Faculty of Medical and Health Sciences, Tsukuba International University, Ibaraki, Japan
| | - David Wright
- Department of Neuroscience, Central Clinical School, Monash University, Melbourne, VIC, Australia.,Florey Institute of Neuroscience and Mental Health, Parkville, VIC, Australia
| | - Tatsuya Higashi
- Department of Molecular Imaging and Theranostics, National Institute of Radiological Sciences, National Institutes for Quantum and Radiological Science and Technology (QST), Chiba, Japan.,Group of Quantum-State Controlled MRI, QST, Chiba, Japan
| | - Ichio Aoki
- Department of Molecular Imaging and Theranostics, National Institute of Radiological Sciences, National Institutes for Quantum and Radiological Science and Technology (QST), Chiba, Japan.,Group of Quantum-State Controlled MRI, QST, Chiba, Japan
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11
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Age-related Changes in Eye, Brain and Visuomotor Behavior in the DBA/2J Mouse Model of Chronic Glaucoma. Sci Rep 2018; 8:4643. [PMID: 29545576 PMCID: PMC5854610 DOI: 10.1038/s41598-018-22850-4] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2016] [Accepted: 03/02/2018] [Indexed: 12/19/2022] Open
Abstract
Although elevated intraocular pressure (IOP) and age are major risk factors for glaucoma, their effects on glaucoma pathogenesis remain unclear. This study examined the onset and progression of glaucomatous changes to ocular anatomy and physiology, structural and physiological brain integrity, and visuomotor behavior in the DBA/2J mice via non-invasive tonometry, multi-parametric magnetic resonance imaging (MRI) and optokinetic assessments from 5 to 12 months of age. Using T2-weighted MRI, diffusion tensor MRI, and manganese-enhanced MRI, increasing IOP elevation at 9 and 12 months old coincided with anterior chamber deepening, altered fractional anisotropy and radial diffusivity of the optic nerve and optic tract, as well as reduced anterograde manganese transport along the visual pathway respectively in the DBA/2J mice. Vitreous body elongation and visuomotor function deterioration were observed until 9 months old, whereas axial diffusivity only decreased at 12 months old in diffusion tensor MRI. Under the same experimental settings, C57BL/6J mice only showed modest age-related changes. Taken together, these results indicate that the anterior and posterior visual pathways of the DBA/2J mice exhibit differential susceptibility to glaucomatous neurodegeneration observable by in vivo multi-modal examinations.
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12
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Schroeter A, Grandjean J, Schlegel F, Saab BJ, Rudin M. Contributions of structural connectivity and cerebrovascular parameters to functional magnetic resonance imaging signals in mice at rest and during sensory paw stimulation. J Cereb Blood Flow Metab 2017; 37:2368-2382. [PMID: 27596833 PMCID: PMC5531337 DOI: 10.1177/0271678x16666292] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Previously, we reported widespread bilateral increases in stimulus-evoked functional magnetic resonance imaging signals in mouse brain to unilateral sensory paw stimulation. We attributed the pattern to arousal-related cardiovascular changes overruling cerebral autoregulation thereby masking specific signal changes elicited by local neuronal activity. To rule out the possibility that interhemispheric neuronal communication might contribute to bilateral functional magnetic resonance imaging responses, we compared stimulus-evoked functional magnetic resonance imaging responses to unilateral hindpaw stimulation in acallosal I/LnJ, C57BL/6, and BALB/c mice. We found bilateral blood-oxygenation-level dependent signal changes in all three strains, ruling out a dominant contribution of transcallosal communication as reason for bilaterality. Analysis of functional connectivity derived from resting-state functional magnetic resonance imaging, revealed that bilateral cortical functional connectivity is largely abolished in I/LnJ animals. Cortical functional connectivity in all strains correlated with structural connectivity in corpus callosum as revealed by diffusion tensor imaging. Given the profound influence of systemic hemodynamics on stimulus-evoked functional magnetic resonance imaging outcomes, we evaluated whether functional connectivity data might be affected by cerebrovascular parameters, i.e. baseline cerebral blood volume, vascular reactivity, and reserve. We found that effects of cerebral hemodynamics on functional connectivity are largely outweighed by dominating contributions of structural connectivity. In contrast, contributions of transcallosal interhemispheric communication to the occurrence of ipsilateral functional magnetic resonance imaging response of equal amplitude to unilateral stimuli seem negligible.
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Affiliation(s)
- Aileen Schroeter
- 1 Institute for Biomedical Engineering, University and ETH Zurich, Zurich, Switzerland.,2 Neuroscience Center Zurich, University and ETH Zurich, Zurich, Switzerland
| | - Joanes Grandjean
- 1 Institute for Biomedical Engineering, University and ETH Zurich, Zurich, Switzerland.,2 Neuroscience Center Zurich, University and ETH Zurich, Zurich, Switzerland
| | - Felix Schlegel
- 1 Institute for Biomedical Engineering, University and ETH Zurich, Zurich, Switzerland.,2 Neuroscience Center Zurich, University and ETH Zurich, Zurich, Switzerland
| | - Bechara J Saab
- 2 Neuroscience Center Zurich, University and ETH Zurich, Zurich, Switzerland.,3 Preclinical Laboratory for Translational Research into Affective Disorders, University of Zurich Hospital for Psychiatry, Zurich, Switzerland
| | - Markus Rudin
- 1 Institute for Biomedical Engineering, University and ETH Zurich, Zurich, Switzerland.,2 Neuroscience Center Zurich, University and ETH Zurich, Zurich, Switzerland.,4 Institute of Pharmacology and Toxicology, University of Zurich, Zurich, Switzerland
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13
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Tang Z, Wang J, Xiao Z, Sun X, Feng X, Tang W, Chen Q, Wu L, Wang R, Zhong Y, Wang W, Luo J. Manganese-enhanced magnetic resonance imaging combined with electrophysiology in the evaluation of visual pathway in experimental rat models with monocular blindness. Brain Behav 2017; 7:e00731. [PMID: 28729937 PMCID: PMC5516605 DOI: 10.1002/brb3.731] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/12/2016] [Revised: 04/15/2017] [Accepted: 04/17/2017] [Indexed: 12/12/2022] Open
Abstract
PURPOSE Our study aimed to explore the feasibility of manganese-enhanced magnetic resonance imaging (MEMRI) combined with visual evoked potentials (VEP) and auditory evoked visual cortex responses (AVR) in evaluating for the establishment of visual/auditory compensatory pathways after monocular blindness. MATERIALS AND METHODS A total of 14 healthy neonatal male Sprague-Dawley rats were randomly divided into two groups (n = 7 for Groups A and B). Right optic nerve (ON) transection was performed on the 7 rats of Group A to obtain a monocularly blind model, and the 7 rats of Group B were chosen as the control group. Four months later, 400 mmol MnCl2 was injected into the left eye in both groups via intravitreal injection. The changes in the visual pathways projected from the blind eye and the remaining eye in Group A and the normal eyes in Group B were compared to determine if new visual compensatory pathways were established. Additionally, VEP tests were performed to determine complete blindness, and AVR examinations were performed to help identify the generation of auditory compensatory function. RESULTS The VEP test indicated complete visual loss after ON transection. In the monocularly blind rats, the contrast-to-noise ratio (CNR) of ON, optic tract (OT), lateral geniculate nucleus (LGN), superior colliculus (SC), optic radiation (OR) and visual cortex (VC) of visual pathway projected from the left eye was significantly higher than that of the right pathway (p < .001). Moreover, the CNR of ON, OT, LGN, SC, OR and VC in the visual pathway projected from the left eye of monocularly blind rats was significantly lower than those of normal rats (p < .05). The AVR results revealed that the corresponding bilateral visual cortex in monocularly blind rats did not respond to the auditory stimulus or showed dissimilation with the low frequency. CONCLUSION MEMRI combined with electrophysiology, including VEP and AVR, may be potentially helpful in the evaluation of the possible generation of new visual/auditory compensatory pathways after monocular blindness.
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Affiliation(s)
- Zuohua Tang
- Department of Radiology Eye and ENT Hospital of Shanghai Medical School Fudan University Shanghai China
| | - Jie Wang
- Department of Radiotherapy Eye and ENT Hospital of Shanghai Medical School Fudan University Shanghai China
| | - Zebin Xiao
- Department of Radiology Eye and ENT Hospital of Shanghai Medical School Fudan University Shanghai China
| | - Xinghuai Sun
- State Key Laboratory of Medical Neurobiology Department of Ophthalmology Eye and ENT Hospital of Shanghai Medical School Institutes of Brain Science Fudan University Shanghai China
| | - Xiaoyuan Feng
- Department of Radiology Huashan Hospital of Shanghai Medical School Fudan University Shanghai China
| | - Weijun Tang
- Department of Radiology Huashan Hospital of Shanghai Medical School Fudan University Shanghai China
| | - Qian Chen
- State Key Laboratory of Medical Neurobiology Department of Ophthalmology Eye and ENT Hospital of Shanghai Medical School Institutes of Brain Science Fudan University Shanghai China
| | - Lingjie Wu
- Department of Otolaryngology Eye and ENT Hospital of Shanghai Medical School Fudan University Shanghai China
| | - Rong Wang
- Department of Radiology Eye and ENT Hospital of Shanghai Medical School Fudan University Shanghai China
| | - Yufeng Zhong
- Department of Radiology Eye and ENT Hospital of Shanghai Medical School Fudan University Shanghai China
| | - Wentao Wang
- Central Laboratory Eye and ENT Hospital of Shanghai Medical School Fudan University Shanghai China
| | - Jianfeng Luo
- Health Statistics Shanghai Medical School Fudan University Shanghai China
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14
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Sperry MM, Kandel BM, Wehrli S, Bass KN, Das SR, Dhillon PS, Gee JC, Barr GA. Mapping of pain circuitry in early post-natal development using manganese-enhanced MRI in rats. Neuroscience 2017; 352:180-189. [PMID: 28391012 PMCID: PMC7276061 DOI: 10.1016/j.neuroscience.2017.03.052] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2016] [Revised: 03/08/2017] [Accepted: 03/28/2017] [Indexed: 12/14/2022]
Abstract
Premature or ill full-term infants are subject to a number of noxious procedures as part of their necessary medical care. Although we know that human infants show neural changes in response to such procedures, we know little of the sensory or affective brain circuitry activated by pain. In rodent models, the focus has been on spinal cord and, more recently, midbrain and medulla. The present study assesses activation of brain circuits using manganese-enhanced magnetic resonance imaging (MEMRI). Uptake of manganese, a paramagnetic contrast agent that is transported across active synapses and along axons, was measured in response to a hindpaw injection of dilute formalin in 12-day-old rat pups, the age at which rats begin to show aversion learning and which is roughly the equivalent of full-term human infants. Formalin induced the oft-reported biphasic response at this age and induced a conditioned aversion to cues associated with its injection, thus demonstrating the aversiveness of the stimulation. Morphometric analyses, structural equation modeling and co-expression analysis showed that limbic and sensory paths were activated, the most prominent of which were the prefrontal and anterior cingulate cortices, nucleus accumbens, amygdala, hypothalamus, several brainstem structures, and the cerebellum. Therefore, both sensory and affective circuits, which are activated by pain in the adult, can also be activated by noxious stimulation in 12-day-old rat pups.
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Affiliation(s)
- M M Sperry
- Department of Bioengineering, University of Pennsylvania, United States
| | - B M Kandel
- Penn Image Computing and Science Laboratory, Department of Radiology, University of Pennsylvania, United States
| | - S Wehrli
- NMR Core, Children's Hospital of Philadelphia, United States
| | - K N Bass
- Anesthesiology and Critical Care Medicine, Children's Hospital of Philadelphia, Perelman School of Medicine, University of Pennsylvania, United States
| | - S R Das
- Penn Image Computing and Science Laboratory, Department of Radiology, University of Pennsylvania, United States
| | - P S Dhillon
- Penn Image Computing and Science Laboratory, Department of Radiology, University of Pennsylvania, United States
| | - J C Gee
- Penn Image Computing and Science Laboratory, Department of Radiology, University of Pennsylvania, United States
| | - G A Barr
- Anesthesiology and Critical Care Medicine, Children's Hospital of Philadelphia, Perelman School of Medicine, University of Pennsylvania, United States.
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15
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Tang Z, Wu L, Xiao Z, Sun X, Feng X, Chen Q, Fan J, Wang J, Wang W, Luo J, Jin L. Manganese-enhanced MR imaging (MEMRI) combined with electrophysiology in the study of cross-modal plasticity in binocularly blind rats. Int J Dev Neurosci 2017; 61:12-20. [PMID: 28539242 DOI: 10.1016/j.ijdevneu.2017.05.002] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2017] [Revised: 05/17/2017] [Accepted: 05/17/2017] [Indexed: 12/18/2022] Open
Abstract
Our study aimed to determine and verify the establishment of visual to auditory cross-modal plasticity using manganese-enhanced MR imaging (MEMRI) combined with examinations of the visual evoked potential (VEP), auditory brainstem response (ABR) and bilateral visual cortex response to a bilateral auditory stimulus (AVR). Fourteen healthy male Sprague-Dawley newborn rats were randomly divided into 2 groups (n=7 per group). Optic nerve transection was performed in the 7 rats of Group A three weeks after birth to obtain binocularly blind models, and the 7 rats of Group B were maintained as the control group. The VEP was measured to ensure complete binocular blindness. Four months after the operation, MnCl2 was injected into the left inner ear perilymph of all rats, and an MRI examination was performed 24h after injection. Then, ABR and AVR were measured to detect the generation of auditory compensatory function. The results of the VEP have confirmed complete binocular blindness. The normalized signal intensity of the bilateral medial geniculate nucleus, auditory cortex, visual center (including the lateral geniculate nucleus, superior colliculus and visual cortex) and right hippocampus in binocularly blind rats was significantly increased compared with that in normal rats (P≤0.005), which was confirmed by measurement of the ABR and AVR. Our results suggested that MEMRI combined with electrophysiology can show changes in the auditory and visual pathways of binocularly blind rats and demonstrate the generation of an auditory compensatory pathway.
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Affiliation(s)
- Zuohua Tang
- Department of Radiology, Eye & ENT Hospital of Shanghai Medical School, Fudan University, Shanghai, 200031, China.
| | - Lingjie Wu
- Department of Otolaryngology, Eye & ENT Hospital of Shanghai Medical School, Fudan University, Shanghai, 200031, China
| | - Zebin Xiao
- Department of Radiology, Eye & ENT Hospital of Shanghai Medical School, Fudan University, Shanghai, 200031, China
| | - Xinghuai Sun
- Department of Ophthalmology, Eye & ENT Hospital of Shanghai Medical School, State Key Laboratory of Medical Neurobiology, Institutes of Brain Science, Fudan University, Shanghai, 200031, China.
| | - Xiaoyuan Feng
- Department of Radiology, Huashan Hospital of Shanghai Medical School, Fudan University, Shanghai, 200040, China
| | - Qian Chen
- Department of Ophthalmology, Eye & ENT Hospital of Shanghai Medical School, State Key Laboratory of Medical Neurobiology, Institutes of Brain Science, Fudan University, Shanghai, 200031, China
| | - Jiawen Fan
- Department of Ophthalmology, Eye & ENT Hospital of Shanghai Medical School, State Key Laboratory of Medical Neurobiology, Institutes of Brain Science, Fudan University, Shanghai, 200031, China
| | - Jie Wang
- Department of Radiotherapy, Eye & ENT Hospital of Shanghai Medical School, Fudan University, Shanghai, 200031, China
| | - Wentao Wang
- Central Laboratory, Eye & ENT Hospital of Shanghai Medical School, Fudan University, Shanghai, 200031, China
| | - Jianfeng Luo
- Health Statistics, Shanghai Medical School, Fudan University, Shanghai, 200031, China
| | - Lixin Jin
- Siemens Ltd. Healthcare sector, Shanghai, 201318, China
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16
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Chen Y, Shi CY, Li Y, Hu YT, Han HB, Sun XD, Salvi SS, Ma ZZ. Ability of Mn(2+) to Permeate the Eye and Availability of Manganese-enhanced Magnetic Resonance Imaging for Visual Pathway Imaging via Topical Administration. Chin Med J (Engl) 2017; 129:1822-9. [PMID: 27453232 PMCID: PMC4976571 DOI: 10.4103/0366-6999.186630] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
Background: Manganese-enhanced magnetic resonance imaging (MEMRI) for visual pathway imaging via topical administration requires further research. This study investigated the permeability of the corneal epithelium and corneal toxicity after topical administration of Mn2+ to understand the applicability of MEMRI. Methods: Forty New Zealand rabbits were divided into 0.05 mol/L, 0.10 mol/L, and 0.20 mol/L groups as well as a control group (n = 10 in each group). Each group was further subdivided into epithelium-removed and epithelium-intact subgroups (n = 5 in each subgroup). Rabbits were given 8 drops of MnCl2 in 5 min intervals. The Mn2+ concentrations in the aqueous and vitreous humors were analyzed using inductively coupled plasma-mass spectrometry at different time points. MEMRI scanning was carried out to image the visual pathway after 24 h. The corneal toxicity of Mn2+ was evaluated with corneal imaging and pathology slices. Results: Between the aqueous and vitreous humors, there was a 10 h lag for the peak Mn2+ concentration times. The intraocular Mn2+ concentration increased with the concentration gradients of Mn2+ and was higher in the epithelium-removed subgroup than that in the epithelium-intact subgroup. The enhancement of the visual pathway was achieved in the 0.10 mol/L and 0.20 mol/L epithelium-removed subgroups. The corresponding peak concentrations of Mn2+ were 5087 ± 666 ng/ml, 22920 ± 1188 ng/ml in the aqueous humor and 884 ± 78 ng/ml, 2556 ± 492 ng/ml in the vitreous body, respectively. Corneal injury was evident in the epithelium-removed and 0.20 mol/L epithelium-intact subgroups. Conclusions: The corneal epithelium is a barrier to Mn2+, and the iris and lens septum might be another intraocular barrier to the permeation of Mn2+. An elevated Mn2+ concentration contributes to the increased permeation of Mn2+, higher MEMRI signal, and corneal toxicity. The enhancement of the visual pathway requires an effective Mn2+ concentration in the vitreous body.
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Affiliation(s)
- Yao Chen
- Department of Ophthalmology, Key Laboratory of Vision Loss and Restoration, Ministry of Education, Peking University Third Hospital, Beijing 100191, China
| | - Chun-Yan Shi
- Department of Radiology, Key Laboratory of Magnetic Resonance Imaging Equipment and Technology, Peking University Third Hospital, Beijing 100083, China
| | - Ying Li
- Department of Ophthalmology, Key Laboratory of Vision Loss and Restoration, Ministry of Education, Peking University Third Hospital, Beijing 100191, China
| | - Yun-Tao Hu
- Department of Ophthalmology, Beijing Tsinghua Chang Gung Hospital, Beijing 102218, China
| | - Hong-Bin Han
- Department of Radiology, Key Laboratory of Magnetic Resonance Imaging Equipment and Technology, Peking University Third Hospital, Beijing 100083, China
| | - Xiao-Dong Sun
- Department of Ophthalmology, Affiliated First People's Hospital of Shanghai Jiao Tong University, Shanghai 200080, China
| | - Satyajeet S Salvi
- Department of Ophthalmology, Beijing Tsinghua Chang Gung Hospital, Beijing 102218, China
| | - Zhi-Zhong Ma
- Department of Ophthalmology, Key Laboratory of Vision Loss and Restoration, Ministry of Education, Peking University Third Hospital, Beijing 100191, China
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17
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Chan KC, Zhou IY, Liu SS, van der Merwe Y, Fan SJ, Hung VK, Chung SK, Wu WT, So KF, Wu EX. Longitudinal Assessments of Normal and Perilesional Tissues in Focal Brain Ischemia and Partial Optic Nerve Injury with Manganese-enhanced MRI. Sci Rep 2017; 7:43124. [PMID: 28230106 PMCID: PMC5322351 DOI: 10.1038/srep43124] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2016] [Accepted: 01/19/2017] [Indexed: 01/07/2023] Open
Abstract
Although manganese (Mn) can enhance brain tissues for improving magnetic resonance imaging (MRI) assessments, the underlying neural mechanisms of Mn detection remain unclear. In this study, we used Mn-enhanced MRI to test the hypothesis that different Mn entry routes and spatiotemporal Mn distributions can reflect different mechanisms of neural circuitry and neurodegeneration in normal and injured brains. Upon systemic administration, exogenous Mn exhibited varying transport rates and continuous redistribution across healthy rodent brain nuclei over a 2-week timeframe, whereas in rodents following photothrombotic cortical injury, transient middle cerebral artery occlusion, or neonatal hypoxic-ischemic brain injury, Mn preferentially accumulated in perilesional tissues expressing gliosis or oxidative stress within days. Intravitreal Mn administration to healthy rodents not only allowed tracing of primary visual pathways, but also enhanced the hippocampus and medial amygdala within a day, whereas partial transection of the optic nerve led to MRI detection of degrading anterograde Mn transport at the primary injury site and the perilesional tissues secondarily over 6 weeks. Taken together, our results indicate the different Mn transport dynamics across widespread projections in normal and diseased brains. Particularly, perilesional brain tissues may attract abnormal Mn accumulation and gradually reduce anterograde Mn transport via specific Mn entry routes.
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Affiliation(s)
- 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, Pittsburgh, Pennsylvania, United States.,Department of Bioengineering, Swanson School of Engineering, 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.,Louis J. Fox Center for Vision Restoration, University of Pittsburgh, Pittsburgh, Pennsylvania, United States.,New York University (NYU) Langone Eye Center, NYU Langone Medical Center, Department of Ophthalmology, NYU School of Medicine, New York, New York, United States.,Department of Electrical and Electronic Engineering, The University of Hong Kong, Pokfulam, Hong Kong, China
| | - Iris Y Zhou
- Department of Electrical and Electronic Engineering, The University of Hong Kong, Pokfulam, Hong Kong, China.,Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital and Harvard Medical School, Charlestown, Massachusetts, United States
| | - Stanley S Liu
- NeuroImaging Laboratory, University of Pittsburgh, Pittsburgh, Pennsylvania, United States
| | - Yolandi van der Merwe
- 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, Pittsburgh, Pennsylvania, United States.,Department of Bioengineering, Swanson School of Engineering, University of Pittsburgh, Pittsburgh, Pennsylvania, United States
| | - Shu-Juan Fan
- Department of Electrical and Electronic Engineering, The University of Hong Kong, Pokfulam, Hong Kong, China
| | - Victor K Hung
- School of Biomedical Sciences, The University of Hong Kong, Pokfulam, Hong Kong, China
| | - Sookja K Chung
- School of Biomedical Sciences, The University of Hong Kong, Pokfulam, Hong Kong, China.,Department of Ophthalmology, The University of Hong Kong, Pokfulam, Hong Kong, China
| | - Wu-Tian Wu
- School of Biomedical Sciences, The University of Hong Kong, Pokfulam, Hong Kong, China
| | - Kwok-Fai So
- School of Biomedical Sciences, The University of Hong Kong, Pokfulam, Hong Kong, China.,Department of Ophthalmology, The University of Hong Kong, Pokfulam, Hong Kong, China
| | - Ed X Wu
- Department of Electrical and Electronic Engineering, The University of Hong Kong, Pokfulam, Hong Kong, China.,School of Biomedical Sciences, The University of Hong Kong, Pokfulam, Hong Kong, China
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18
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Gesnik M, Blaize K, Deffieux T, Gennisson JL, Sahel JA, Fink M, Picaud S, Tanter M. 3D functional ultrasound imaging of the cerebral visual system in rodents. Neuroimage 2017; 149:267-274. [PMID: 28167348 PMCID: PMC5387157 DOI: 10.1016/j.neuroimage.2017.01.071] [Citation(s) in RCA: 56] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2016] [Revised: 01/27/2017] [Accepted: 01/30/2017] [Indexed: 12/11/2022] Open
Abstract
3D functional imaging of the whole brain activity during visual task is a challenging task in rodents due to the complex tri-dimensional shape of involved brain regions and the fine spatial and temporal resolutions required to reveal the visual tract. By coupling functional ultrasound (fUS) imaging with a translational motorized stage and an episodic visual stimulation device, we managed to accurately map and to recover the activity of the visual cortices, the Superior Colliculus (SC) and the Lateral Geniculate Nuclei (LGN) in 3D. Cerebral Blood Volume (CBV) responses during visual stimuli were found to be highly correlated with the visual stimulus time profile in visual cortices (r=0.6), SC (r=0.7) and LGN (r=0.7). These responses were found dependent on flickering frequency and contrast, and optimal stimulus parameters for largest CBV increases were obtained. In particular, increasing the flickering frequency higher than 7 Hz revealed a decrease of visual cortices response while the SC response was preserved. Finally, cross-correlation between CBV signals exhibited significant delays (d=0.35 s +/−0.1 s) between blood volume response in SC and visual cortices in response to our visual stimulus. These results emphasize the interest of fUS imaging as a whole brain neuroimaging modality for brain vision studies in rodent models.
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Affiliation(s)
- Marc Gesnik
- Institut Langevin, ESPCI Paris, PSL Research University, CNRS UMR 7587, INSERM U979, 75012 Paris, France.
| | - Kevin Blaize
- Institut de la Vision, Sorbonne Universités UPMC, University of Paris 06, INSERM UMR_S 968, CNRS UMR 7210, 75012 Paris, France
| | - Thomas Deffieux
- Institut Langevin, ESPCI Paris, PSL Research University, CNRS UMR 7587, INSERM U979, 75012 Paris, France
| | - Jean-Luc Gennisson
- Institut Langevin, ESPCI Paris, PSL Research University, CNRS UMR 7587, INSERM U979, 75012 Paris, France
| | - José-Alain Sahel
- Institut de la Vision, Sorbonne Universités UPMC, University of Paris 06, INSERM UMR_S 968, CNRS UMR 7210, 75012 Paris, France; Fondation Ophtalmologique Adolphe de Rothschild, 75019 Paris, France; CHNO des Quinze-Vingts, DHU Sight Restore, INSERM-DGOS CIC 1423, 75012 Paris, France; Department of Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh, 15213 PA, USA; Academie des Sciences, Paris
| | - Mathias Fink
- Institut Langevin, ESPCI Paris, PSL Research University, CNRS UMR 7587, INSERM U979, 75012 Paris, France
| | - Serge Picaud
- Institut de la Vision, Sorbonne Universités UPMC, University of Paris 06, INSERM UMR_S 968, CNRS UMR 7210, 75012 Paris, France
| | - Mickaël Tanter
- Institut Langevin, ESPCI Paris, PSL Research University, CNRS UMR 7587, INSERM U979, 75012 Paris, France
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19
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Huang H, Lovell JF. Advanced Functional Nanomaterials for Theranostics. ADVANCED FUNCTIONAL MATERIALS 2017; 27:1603524. [PMID: 28824357 PMCID: PMC5560626 DOI: 10.1002/adfm.201603524] [Citation(s) in RCA: 134] [Impact Index Per Article: 19.1] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/02/2023]
Abstract
Nanoscale materials have been explored extensively as agents for therapeutic and diagnostic (i.e. theranostic) applications. Research efforts have shifted from exploring new materials in vitro to designing materials that function in more relevant animal disease models, thereby increasing potential for clinical translation. Current interests include non-invasive imaging of diseases, biomarkers and targeted delivery of therapeutic drugs. Here, we discuss some general design considerations of advanced theranostic materials and challenges of their use, from both diagnostic and therapeutic perspectives. Common classes of nanoscale biomaterials, including magnetic nanoparticles, quantum dots, upconversion nanoparticles, mesoporous silica nanoparticles, carbon-based nanoparticles and organic dye-based nanoparticles, have demonstrated potential for both diagnosis and therapy. Variations such as size control and surface modifications can modulate biocompatibility and interactions with target tissues. The needs for improved disease detection and enhanced chemotherapeutic treatments, together with realistic considerations for clinically translatable nanomaterials will be key driving factors for theranostic agent research in the near future.
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Affiliation(s)
- Haoyuan Huang
- Department of Biomedical Engineering, University at Buffalo, State University of New York, Buffalo, New York, 14260, United States
| | - Jonathan F Lovell
- Department of Biomedical Engineering, University at Buffalo, State University of New York, Buffalo, New York, 14260, United States
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20
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Gálosi R, Szalay C, Aradi M, Perlaki G, Pál J, Steier R, Lénárd L, Karádi Z. Identifying non-toxic doses of manganese for manganese-enhanced magnetic resonance imaging to map brain areas activated by operant behavior in trained rats. Magn Reson Imaging 2016; 37:122-133. [PMID: 27889621 DOI: 10.1016/j.mri.2016.11.017] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2016] [Revised: 11/21/2016] [Accepted: 11/22/2016] [Indexed: 12/13/2022]
Abstract
Manganese-enhanced magnetic resonance imaging (MEMRI) offers unique advantages such as studying brain activation in freely moving rats, but its usefulness has not been previously evaluated during operant behavior training. Manganese in a form of MnCl2, at a dose of 20mg/kg, was intraperitoneally infused. The administration was repeated and separated by 24h to reach the dose of 40mg/kg or 60mg/kg, respectively. Hepatotoxicity of the MnCl2 was evaluated by determining serum aspartate aminotransferase, alanine aminotransferase, total bilirubin, albumin and protein levels. Neurological examination was also carried out. The animals were tested in visual cue discriminated operant task. Imaging was performed using a 3T clinical MR scanner. T1 values were determined before and after MnCl2 administrations. Manganese-enhanced images of each animal were subtracted from their baseline images to calculate decrease in the T1 value (ΔT1) voxel by voxel. The subtracted T1 maps of trained animals performing visual cue discriminated operant task, and those of naive rats were compared. The dose of 60mg/kg MnCl2 showed hepatotoxic effect, but even these animals did not exhibit neurological symptoms. The dose of 20 and 40mg/kg MnCl2 increased the number of omissions and did not affect the accuracy of performing the visual cue discriminated operant task. Using the accumulated dose of 40mg/kg, voxels with a significant enhanced ΔT1 value were detected in the following brain areas of the visual cue discriminated operant behavior performed animals compared to those in the controls: the visual, somatosensory, motor and premotor cortices, the insula, cingulate, ectorhinal, entorhinal, perirhinal and piriform cortices, hippocampus, amygdala with amygdalohippocampal areas, dorsal striatum, nucleus accumbens core, substantia nigra, and retrorubral field. In conclusion, the MEMRI proved to be a reliable method to accomplish brain activity mapping in correlation with the operant behavior of freely moving rodents.
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Affiliation(s)
- Rita Gálosi
- Institute of Physiology, Medical School of University of Pécs, Pécs, Hungary.
| | - Csaba Szalay
- Institute of Physiology, Medical School of University of Pécs, Pécs, Hungary.
| | | | - Gábor Perlaki
- Neurosurgery Clinic, Medical School of University of Pécs, Pécs, Hungary; Pécs Diagnostic Center, Pécs, Hungary
| | - József Pál
- Neurosurgery Clinic, Medical School of University of Pécs, Pécs, Hungary
| | - Roy Steier
- Neurosurgery Clinic, Medical School of University of Pécs, Pécs, Hungary.
| | - László Lénárd
- Institute of Physiology, Medical School of University of Pécs, Pécs, Hungary; Molecular Neuroendocrinology and Neurophysiology Research Group, Szentágothai Research Center, University of Pécs, Pécs, Hungary
| | - Zoltán Karádi
- Institute of Physiology, Medical School of University of Pécs, Pécs, Hungary; Molecular Neuroendocrinology and Neurophysiology Research Group, Szentágothai Research Center, University of Pécs, Pécs, Hungary
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21
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Kancherla S, Kohler WJ, van der Merwe Y, Chan KC. In Vivo Evaluation of the Visual Pathway in Streptozotocin-Induced Diabetes by Diffusion Tensor MRI and Contrast Enhanced MRI. PLoS One 2016; 11:e0165169. [PMID: 27768755 PMCID: PMC5074510 DOI: 10.1371/journal.pone.0165169] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2016] [Accepted: 10/07/2016] [Indexed: 02/07/2023] Open
Abstract
Visual function has been shown to deteriorate prior to the onset of retinopathy in some diabetic patients and experimental animal models. This suggests the involvement of the brain's visual system in the early stages of diabetes. In this study, we tested this hypothesis by examining the integrity of the visual pathway in a diabetic rat model using in vivo multi-modal magnetic resonance imaging (MRI). Ten-week-old Sprague-Dawley rats were divided into an experimental diabetic group by intraperitoneal injection of 65 mg/kg streptozotocin in 0.01 M citric acid, and a sham control group by intraperitoneal injection of citric acid only. One month later, diffusion tensor MRI (DTI) was performed to examine the white matter integrity in the brain, followed by chromium-enhanced MRI of retinal integrity and manganese-enhanced MRI of anterograde manganese transport along the visual pathway. Prior to MRI experiments, the streptozotocin-induced diabetic rats showed significantly smaller weight gain and higher blood glucose level than the control rats. DTI revealed significantly lower fractional anisotropy and higher radial diffusivity in the prechiasmatic optic nerve of the diabetic rats compared to the control rats. No apparent difference was observed in the axial diffusivity of the optic nerve, the chromium enhancement in the retina, or the manganese enhancement in the lateral geniculate nucleus and superior colliculus between groups. Our results suggest that streptozotocin-induced diabetes leads to early injury in the optic nerve when no substantial change in retinal integrity or anterograde transport along the visual pathways was observed in MRI using contrast agent enhancement. DTI may be a useful tool for detecting and monitoring early pathophysiological changes in the visual system of experimental diabetes non-invasively.
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Affiliation(s)
- Swarupa Kancherla
- NeuroImaging Laboratory, University of Pittsburgh, Pittsburgh, PA, United States of America
- UPMC Eye Center, Ophthalmology and Visual Science Research Center, Department of Ophthalmology, School of Medicine, University of Pittsburgh, Pittsburgh, PA, United States of America
| | - William J. Kohler
- NeuroImaging Laboratory, University of Pittsburgh, Pittsburgh, PA, United States of America
- UPMC Eye Center, Ophthalmology and Visual Science Research Center, Department of Ophthalmology, School of Medicine, University of Pittsburgh, Pittsburgh, PA, United States of America
| | - Yolandi van der Merwe
- NeuroImaging Laboratory, University of Pittsburgh, Pittsburgh, PA, United States of America
- UPMC Eye Center, Ophthalmology and Visual Science Research Center, Department of Ophthalmology, School of Medicine, University of Pittsburgh, Pittsburgh, PA, United States of America
- Department of Bioengineering, Swanson School of Engineering, University of Pittsburgh, Pittsburgh, PA, United States of America
- McGowan Institute for Regenerative Medicine, University of Pittsburgh, Pittsburgh, PA, United States of America
- Louis J. Fox Center for Vision Restoration, University of Pittsburgh, Pittsburgh, PA, United States of America
| | - Kevin C. Chan
- NeuroImaging Laboratory, University of Pittsburgh, Pittsburgh, PA, United States of America
- UPMC Eye Center, Ophthalmology and Visual Science Research Center, Department of Ophthalmology, School of Medicine, University of Pittsburgh, Pittsburgh, PA, United States of America
- Department of Bioengineering, Swanson School of Engineering, University of Pittsburgh, Pittsburgh, PA, United States of America
- McGowan Institute for Regenerative Medicine, University of Pittsburgh, Pittsburgh, PA, United States of America
- Louis J. Fox Center for Vision Restoration, University of Pittsburgh, Pittsburgh, PA, United States of America
- Center for the Neural Basis of Cognition, University of Pittsburgh and Carnegie Mellon University, Pittsburgh, PA, United States of America
- Department of Electrical and Electronic Engineering, The University of Hong Kong, Hong Kong, China
- * E-mail:
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22
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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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23
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Chan RW, Ho LC, Zhou IY, Gao PP, Chan KC, Wu EX. Structural and Functional Brain Remodeling during Pregnancy with Diffusion Tensor MRI and Resting-State Functional MRI. PLoS One 2015; 10:e0144328. [PMID: 26658306 PMCID: PMC4675543 DOI: 10.1371/journal.pone.0144328] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2015] [Accepted: 11/17/2015] [Indexed: 01/25/2023] Open
Abstract
Although pregnancy-induced hormonal changes have been shown to alter the brain at the neuronal level, the exact effects of pregnancy on brain at the tissue level remain unclear. In this study, diffusion tensor imaging (DTI) and resting-state functional MRI (rsfMRI) were employed to investigate and document the effects of pregnancy on the structure and function of the brain tissues. Fifteen Sprague-Dawley female rats were longitudinally studied at three days before mating (baseline) and seventeen days after mating (G17). G17 is equivalent to the early stage of the third trimester in humans. Seven age-matched nulliparous female rats served as non-pregnant controls and were scanned at the same time-points. For DTI, diffusivity was found to generally increase in the whole brain during pregnancy, indicating structural changes at microscopic levels that facilitated water molecular movement. Regionally, mean diffusivity increased more pronouncedly in the dorsal hippocampus while fractional anisotropy in the dorsal dentate gyrus increased significantly during pregnancy. For rsfMRI, bilateral functional connectivity in the hippocampus increased significantly during pregnancy. Moreover, fractional anisotropy increase in the dentate gyrus appeared to correlate with the bilateral functional connectivity increase in the hippocampus. These findings revealed tissue structural modifications in the whole brain during pregnancy, and that the hippocampus was structurally and functionally remodeled in a more marked manner.
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Affiliation(s)
- 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
| | - Leon C. Ho
- 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
| | - Patrick P. Gao
- 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
| | - Kevin C. Chan
- UPMC Eye Center, Ophthalmology and Visual Science Research Center, Department of Ophthalmology, University of Pittsburgh, Pittsburgh, PA, United States of America
| | - 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
- * E-mail:
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24
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Nau AC, Murphy MC, Chan KC. Use of sensory substitution devices as a model system for investigating cross-modal neuroplasticity in humans. Neural Regen Res 2015; 10:1717-9. [PMID: 26807088 PMCID: PMC4705765 DOI: 10.4103/1673-5374.169612] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/15/2015] [Indexed: 12/24/2022] Open
Affiliation(s)
- Amy C. Nau
- 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
| | - Matthew C. Murphy
- 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, Pittsburgh, PA, USA
| | - Kevin C. Chan
- 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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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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26
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Szulc KU, Lerch JP, Nieman BJ, Bartelle BB, Friedel M, Suero-Abreu GA, Watson C, Joyner AL, Turnbull DH. 4D MEMRI atlas of neonatal FVB/N mouse brain development. Neuroimage 2015; 118:49-62. [PMID: 26037053 DOI: 10.1016/j.neuroimage.2015.05.029] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2014] [Revised: 05/11/2015] [Accepted: 05/13/2015] [Indexed: 11/19/2022] Open
Abstract
The widespread use of the mouse as a model system to study brain development has created the need for noninvasive neuroimaging methods that can be applied to early postnatal mice. The goal of this study was to optimize in vivo three- (3D) and four-dimensional (4D) manganese (Mn)-enhanced MRI (MEMRI) approaches for acquiring and analyzing data from the developing mouse brain. The combination of custom, stage-dependent holders and self-gated (motion-correcting) 3D MRI sequences enabled the acquisition of high-resolution (100-μm isotropic), motion artifact-free brain images with a high level of contrast due to Mn-enhancement of numerous brain regions and nuclei. We acquired high-quality longitudinal brain images from two groups of FVB/N strain mice, six mice per group, each mouse imaged on alternate odd or even days (6 3D MEMRI images at each day) covering the developmental stages between postnatal days 1 to 11. The effects of Mn-exposure, anesthesia and MRI were assessed, showing small but significant transient effects on body weight and brain volume, which recovered with time and did not result in significant morphological differences when compared to controls. Metrics derived from deformation-based morphometry (DBM) were used for quantitative analysis of changes in volume and position of a number of brain regions. The cerebellum, a brain region undergoing significant changes in size and patterning at early postnatal stages, was analyzed in detail to demonstrate the spatiotemporal characterization made possible by this new atlas of mouse brain development. These results show that MEMRI is a powerful tool for quantitative analysis of mouse brain development, with great potential for in vivo phenotype analysis in mouse models of neurodevelopmental diseases.
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Affiliation(s)
- Kamila U Szulc
- Skirball Institute of Biomolecular Medicine, New York University School of Medicine, New York, NY, USA; Biomedical Imaging, New York University School of Medicine, New York, NY, USA
| | - Jason P Lerch
- Mouse Imaging Centre, Hospital for Sick Children, Toronto, ON, Canada; Department of Medical Biophysics, University of Toronto, Toronto, ON, Canada
| | - Brian J Nieman
- Mouse Imaging Centre, Hospital for Sick Children, Toronto, ON, Canada; Department of Medical Biophysics, University of Toronto, Toronto, ON, Canada; Ontario Institute for Cancer Research, Toronto, ON, Canada
| | - Benjamin B Bartelle
- Skirball Institute of Biomolecular Medicine, New York University School of Medicine, New York, NY, USA; Molecular Biophysics Graduate Programs, New York University School of Medicine, New York, NY, USA
| | - Miriam Friedel
- Mouse Imaging Centre, Hospital for Sick Children, Toronto, ON, Canada
| | - Giselle A Suero-Abreu
- Skirball Institute of Biomolecular Medicine, New York University School of Medicine, New York, NY, USA; Biomedical Imaging, New York University School of Medicine, New York, NY, USA
| | - Charles Watson
- Health Sciences, Curtin University, Perth, Western Australia, Australia
| | - Alexandra L Joyner
- Developmental Biology Program, Sloan-Kettering Institute, New York, NY, USA
| | - Daniel H Turnbull
- Skirball Institute of Biomolecular Medicine, New York University School of Medicine, New York, NY, USA; Biomedical Imaging, New York University School of Medicine, New York, NY, USA; Molecular Biophysics Graduate Programs, New York University School of Medicine, New York, NY, USA; Department of Radiology, New York University School of Medicine, New York, NY, USA; Department of Pathology, New York University School of Medicine, New York, NY, USA.
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27
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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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Ho LC, Sigal IA, Jan NJ, Squires A, Tse Z, Wu EX, Kim SG, Schuman JS, Chan KC. Magic angle-enhanced MRI of fibrous microstructures in sclera and cornea with and without intraocular pressure loading. Invest Ophthalmol Vis Sci 2014; 55:5662-72. [PMID: 25103267 DOI: 10.1167/iovs.14-14561] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
PURPOSE The structure and biomechanics of the sclera and cornea are central to several eye diseases such as glaucoma and myopia. However, their roles remain unclear, partly because of limited noninvasive techniques to assess their fibrous microstructures globally, longitudinally, and quantitatively. We hypothesized that magic angle-enhanced magnetic resonance imaging (MRI) can reveal the structural details of the corneoscleral shell and their changes upon intraocular pressure (IOP) elevation. METHODS Seven ovine eyes were extracted and fixed at IOP = 50 mm Hg to mimic ocular hypertension, and another 11 eyes were unpressurized. The sclera and cornea were scanned at different angular orientations relative to the main magnetic field inside a 9.4-Tesla MRI scanner. Relative MRI signal intensities and intrinsic transverse relaxation times (T2 and T2*) were determined to quantify the magic angle effect on the corneoscleral shells. Three loaded and eight unloaded tendon samples were scanned as controls. RESULTS At magic angle, high-resolution MRI revealed distinct scleral and corneal lamellar fibers, and light/dark bands indicative of collagen fiber crimps in the sclera and tendon. Magic angle enhancement effect was the strongest in tendon and the least strong in cornea. Loaded sclera, cornea, and tendon possessed significantly higher T2 and T2* than unloaded tissues at magic angle. CONCLUSIONS Magic angle-enhanced MRI can detect ocular fibrous microstructures without contrast agents or coatings and can reveal their MR tissue property changes with IOP loading. This technique may open up new avenues for assessment of the biomechanical and biochemical properties of ocular tissues in aging and in diseases involving the corneoscleral shell.
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Affiliation(s)
- Leon C Ho
- NeuroImaging Laboratory, University of Pittsburgh, Pittsburgh, Pennsylvania, United States
| | - 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 Department of Bioengineering, Swanson School of Engineering, University of Pittsburgh, Pittsburgh, Pennsylvania, United States
| | - Ning-Jiun Jan
- UPMC Eye Center, Ophthalmology and Visual Science Research Center, Department of Ophthalmology, School of Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania, United States Department of Bioengineering, Swanson School of Engineering, University of Pittsburgh, Pittsburgh, Pennsylvania, United States
| | - Alexander Squires
- Medical Robotics Lab, College of Engineering, University of Georgia, Athens, Georgia, United States
| | - Zion Tse
- Medical Robotics Lab, College of Engineering, University of Georgia, Athens, Georgia, United States
| | - Ed X Wu
- Department of Electrical and Electronic Engineering, The University of Hong Kong, Pokfulam, Hong Kong, China
| | - Seong-Gi Kim
- NeuroImaging Laboratory, University of Pittsburgh, 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 the Neural Basis of Cognition, University of Pittsburgh and Carnegie Mellon University, Pittsburgh, Pennsylvania, United States
| | - 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 Department of Bioengineering, Swanson School of Engineering, University of Pittsburgh, Pittsburgh, Pennsylvania, United States Clinical and Translational Science Institute, University of Pittsburgh, Pittsburgh, Pennsylvania, United States
| | - Kevin C Chan
- NeuroImaging Laboratory, University of Pittsburgh, Pittsburgh, Pennsylvania, United States UPMC Eye Center, Ophthalmology and Visual Science Research Center, Department of Ophthalmology, School of Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania, United States Department of Bioengineering, Swanson School of Engineering, 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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29
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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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