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Burri C, Salzmann S, Wandel J, Hoffmann L, Považay B, Meier C, Frenz M. Real-time OCT feedback-controlled RPE photodisruption in ex vivo porcine eyes using 8 microsecond laser pulses. BIOMEDICAL OPTICS EXPRESS 2023; 14:6328-6349. [PMID: 38420306 PMCID: PMC10898567 DOI: 10.1364/boe.503941] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/22/2023] [Revised: 10/24/2023] [Accepted: 11/12/2023] [Indexed: 03/02/2024]
Abstract
Selective retinal pigment epithelium (RPE) photodisruption requires reliable real-time feedback dosimetry (RFD) to prevent unwanted overexposure. In this study, optical coherence tomography (OCT) based RFD was investigated in ex vivo porcine eyes exposed to laser pulses of 8 µs duration (wavelength: 532 nm, exposure area: 90 × 90 µm2, radiant exposure: 247 to 1975 mJ/µm2). For RFD, fringe washouts in time-resolved OCT M-scans (central wavelength: 870 nm, scan rate: 85 kHz) were compared to an RPE cell viability assay. Statistical analysis revealed a moderate correlation between RPE lesion size and applied treatment energy, suggesting RFD adaptation to inter- and intraindividual RPE pigmentation and ocular transmission.
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Affiliation(s)
- Christian Burri
- optoLab, Institute for Human Centered Engineering, Bern University of Applied Sciences, Biel, Switzerland
- Biomedical Photonics Group, Institute of Applied Physics, University of Bern, Bern, Switzerland
| | - Simon Salzmann
- optoLab, Institute for Human Centered Engineering, Bern University of Applied Sciences, Biel, Switzerland
| | - Jasmin Wandel
- Institute for Optimisation and Data Analysis, Bern University of Applied Sciences, Burgdorf, Switzerland
| | - Leonie Hoffmann
- optoLab, Institute for Human Centered Engineering, Bern University of Applied Sciences, Biel, Switzerland
| | - Boris Považay
- optoLab, Institute for Human Centered Engineering, Bern University of Applied Sciences, Biel, Switzerland
| | - Christoph Meier
- optoLab, Institute for Human Centered Engineering, Bern University of Applied Sciences, Biel, Switzerland
| | - Martin Frenz
- Biomedical Photonics Group, Institute of Applied Physics, University of Bern, Bern, Switzerland
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Deng S, Huang S, Yang A, Muir ER. Imaging ocular water inflow in the mouse with deuterium oxide MRI. Magn Reson Imaging 2023; 101:47-53. [PMID: 36965834 PMCID: PMC11104035 DOI: 10.1016/j.mri.2023.03.017] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2023] [Accepted: 03/21/2023] [Indexed: 03/27/2023]
Abstract
Abnormal intraocular fluid flow or clearance is involved with a variety of eye diseases such as glaucoma and diabetic retinopathy, but measurement of water exchange dynamics in the vitreous and aqueous remain challenging. 2H MRI can be used to image deuterium oxide (D₂O) as a tracer, but the signal-to-noise ratio for deuterium is low due to its low concentration, which has hampered its application to imaging the eye. To overcome this challenge, we investigated the feasibility of direct D2O MRI to measure water dynamics in the mouse eye. The balanced steady-state free precession (bSSFP) sequence provided substantially higher signal-to-noise ratio for imaging D2O in fluid compared to standard gradient echo and spin echo sequences. bSSFP allowed dynamic imaging of intraocular water inflow in the mouse with 41 s temporal resolution. The inflow rate in the vitreous was found to be faster than in the aqueous. These studies demonstrate the feasibility of in vivo imaging of water inflow dynamics into the both the vitreous and aqueous in mice, which could be useful in studies of abnormal fluid exchange in rodent models of eye disease.
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Affiliation(s)
- Shengwen Deng
- Department of Radiology, University Hospitals Cleveland Medical Center and Case Western Reserve University, Cleveland, OH, United States; Research Imaging Institute, University of Texas Health Science Center, San Antonio, TX, United States
| | - Shiliang Huang
- Research Imaging Institute, University of Texas Health Science Center, San Antonio, TX, United States
| | - Alivia Yang
- Department of Radiology, School of Medicine, Stony Brook University, Stony Brook, NY, United States
| | - Eric R Muir
- Research Imaging Institute, University of Texas Health Science Center, San Antonio, TX, United States; Department of Radiology, School of Medicine, Stony Brook University, Stony Brook, NY, United States.
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Zhang X, Zhang J. The human brain in a high altitude natural environment: A review. Front Hum Neurosci 2022; 16:915995. [PMID: 36188182 PMCID: PMC9520777 DOI: 10.3389/fnhum.2022.915995] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2022] [Accepted: 07/25/2022] [Indexed: 12/04/2022] Open
Abstract
With the advancement of in vivo magnetic resonance imaging (MRI) technique, more detailed information about the human brain at high altitude (HA) has been revealed. The present review aimed to draw a conclusion regarding changes in the human brain in both unacclimatized and acclimatized states in a natural HA environment. Using multiple advanced analysis methods that based on MRI as well as electroencephalography, the modulations of brain gray and white matter morphology and the electrophysiological mechanisms underlying processing of cognitive activity have been explored in certain extent. The visual, motor and insular cortices are brain regions seen to be consistently affected in both HA immigrants and natives. Current findings regarding cortical electrophysiological and blood dynamic signals may be related to cardiovascular and respiratory regulations, and may clarify the mechanisms underlying some behaviors at HA. In general, in the past 10 years, researches on the brain at HA have gone beyond cognitive tests. Due to the sample size is not large enough, the current findings in HA brain are not very reliable, and thus much more researches are needed. Moreover, the histological and genetic bases of brain structures at HA are also needed to be elucidated.
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Affiliation(s)
- Xinjuan Zhang
- Institute of Brain Diseases and Cognition, School of Medicine, Xiamen University, Xiamen, China
- Department of Physiology, School of Medicine, Xiamen University, Xiamen, China
| | - Jiaxing Zhang
- Institute of Brain Diseases and Cognition, School of Medicine, Xiamen University, Xiamen, China
- Department of Physiology, School of Medicine, Xiamen University, Xiamen, China
- *Correspondence: Jiaxing Zhang,
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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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Lucas-Ruiz F, Galindo-Romero C, Albaladejo-García V, Vidal-Sanz M, Agudo-Barriuso M. Mechanisms implicated in the contralateral effect in the central nervous system after unilateral injury: focus on the visual system. Neural Regen Res 2021; 16:2125-2131. [PMID: 33818483 PMCID: PMC8354113 DOI: 10.4103/1673-5374.310670] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2020] [Revised: 11/21/2020] [Accepted: 01/11/2021] [Indexed: 12/21/2022] Open
Abstract
The retina, as part of the central nervous system is an ideal model to study the response of neurons to injury and disease and to test new treatments. During the last decade is becoming clear that unilateral lesions in bilateral areas of the central nervous system trigger an inflammatory response in the contralateral uninjured site. This effect has been better studied in the visual system where, as a rule, one retina is used as experimental and the other as control. Contralateral retinas in unilateral models of retinal injury show neuronal degeneration and glial activation. The mechanisms by which this adverse response in the central nervous system occurs are discussed in this review, focusing primarily on the visual system.
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Affiliation(s)
- Fernando Lucas-Ruiz
- Departamento de Oftalmología, Facultad de Medicina, Universidad de Murcia and Instituto Murciano de Investigación Biosanitaria-Virgen de la Arrixaca (IMIBArrixaca) Murcia, Spain
| | - Caridad Galindo-Romero
- Departamento de Oftalmología, Facultad de Medicina, Universidad de Murcia and Instituto Murciano de Investigación Biosanitaria-Virgen de la Arrixaca (IMIBArrixaca) Murcia, Spain
| | - Virginia Albaladejo-García
- Departamento de Oftalmología, Facultad de Medicina, Universidad de Murcia and Instituto Murciano de Investigación Biosanitaria-Virgen de la Arrixaca (IMIBArrixaca) Murcia, Spain
| | - Manuel Vidal-Sanz
- Departamento de Oftalmología, Facultad de Medicina, Universidad de Murcia and Instituto Murciano de Investigación Biosanitaria-Virgen de la Arrixaca (IMIBArrixaca) Murcia, Spain
| | - Marta Agudo-Barriuso
- Departamento de Oftalmología, Facultad de Medicina, Universidad de Murcia and Instituto Murciano de Investigación Biosanitaria-Virgen de la Arrixaca (IMIBArrixaca) Murcia, Spain
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Cortical Visual Impairment in Childhood: 'Blindsight' and the Sprague Effect Revisited. Brain Sci 2021; 11:brainsci11101279. [PMID: 34679344 PMCID: PMC8533908 DOI: 10.3390/brainsci11101279] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2021] [Revised: 09/14/2021] [Accepted: 09/24/2021] [Indexed: 11/29/2022] Open
Abstract
The paper discusses and provides support for diverse processes of brain plasticity in visual function after damage in infancy and childhood in comparison with injury that occurs in the adult brain. We provide support and description of neuroplastic mechanisms in childhood that do not seemingly exist in the same way in the adult brain. Examples include the ability to foster the development of thalamocortical connectivities that can circumvent the lesion and reach their cortical destination in the occipital cortex as the developing brain is more efficient in building new connections. Supporting this claim is the fact that in those with central visual field defects we can note that the extrastriatal visual connectivities are greater when a lesion occurs earlier in life as opposed to in the neurologically mature adult. The result is a significantly more optimized system of visual and spatial exploration within the ‘blind’ field of view. The discussion is provided within the context of “blindsight” and the “Sprague Effect”.
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7
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In vivo MRI evaluation of early postnatal development in normal and impaired rat eyes. Sci Rep 2021; 11:15513. [PMID: 34330952 PMCID: PMC8324881 DOI: 10.1038/s41598-021-93991-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/25/2020] [Accepted: 07/01/2021] [Indexed: 11/08/2022] Open
Abstract
This study employed in vivo 7-T magnetic resonance imaging (MRI) to evaluate the postnatal ocular growth patterns under normal development or neonatal impairments in Sprague-Dawley rats. Using T2-weighted imaging on healthy rats from postnatal day (P) 1 (newborn) to P60 (adult), the volumes of the anterior chamber and posterior chamber (ACPC), lens, and vitreous humor increased logistically with ACPC expanding by 33-fold and the others by fivefold. Intravitreal potassium dichromate injection at P1, P7, and P14 led to T1-weighted signal enhancement in the developing retina by 188-289%. Upon unilateral hypoxic-ischemic encephalopathy at P7, monocular deprivation at P15, and monocular enucleation at P1, T2-weighted imaging of the adult rats showed decreased ocular volumes to different extents. In summary, in vivo high-field MRI allows for non-invasive evaluation of early postnatal development in the normal and impaired rat eyes. Chromium-enhanced MRI appeared effective in examining the developing retina before natural eyelid opening at P14 with relevance to lipid metabolism. The reduced ocular volumes upon neonatal visual impairments provided evidence to the emerging problems of why some impaired visual outcomes cannot be solely predicted by neurological assessments and suggested the need to look into both the eye and the brain under such conditions.
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Spectral-domain OCT changes in retina and optic nerve in children with hypoxic-ischaemic encephalopathy. Graefes Arch Clin Exp Ophthalmol 2020; 259:1343-1355. [PMID: 33141256 PMCID: PMC8102460 DOI: 10.1007/s00417-020-04996-y] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2020] [Revised: 10/08/2020] [Accepted: 10/23/2020] [Indexed: 12/19/2022] Open
Abstract
Purpose To evaluate the effect of neonatal hypoxic–ischaemic injury on the retina and the optic nerve and to correlate ocular damage with systemic parameters, laboratory tests, neurological imaging and therapeutic hypothermia at birth. Methods Forty-one children with hypoxic–ischaemic encephalopathy (HIE) at birth (9.09 ± 3.78 years) and a control group of 38 healthy subjects (9.57 ± 3.47 years) were enrolled in a cohort study. The HIE population was divided into three subgroups, based on the degree of encephalopathy according to Sarnat score and the treatment with therapeutic hypothermia (TH): Sarnat score I not treated with hypothermia, Sarnat score II-III treated with TH and Sarnat score II-III not subjected to TH. Total macular thickness, individual retinal layers and peripapillary nerve fibre layer thickness were measured with spectral-domain optical coherence tomography. Clinical data of perinatal period of HIE children were collected: APGAR score, pH and base excess of funiculus blood at birth, apnoea duration, brain ultrasound, cerebral MRI ischaemic lesions and blood chemistry tests. Results Children with Sarnat score I did not show a reduction of peripapillary nerve fibres and ganglion cell layer compared to the control group (p = 0.387, p = 0.316). Peripapillary nerve fibre layer was 109.06 ± 7.79 μm in children with Sarnat score II-III treated with TH, 108.31 ± 7.83 μm in subjects with Sarnat score II-III not subjected to TH and 114.27 ± 6.81 μm in the control group (p = 0.028, p = 0.007). Ganglion cell layer was thinner in children with Sarnat score II-III treated with TH (50.31 ± 5.13 μm) compared to the control group (54.04 ± 2.81 μm) (p = 0.01). Inner retinal layers damage correlated with C-reactive protein and lactate dehydrogenase increase, while higher levels of total bilirubin were protective against retinal impairment (p < 0.05). Cerebral oedema was related to peripapillary nerve fibre layer damage (p = 0.046). Conclusions Thickness reduction of inner retinal layer and peripapillary nerve fibre impairment was related to encephalopathy severity. Ocular damage was associated with inflammation and cerebral oedema following hypoxic–ischaemic damage.
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Ma F, Li T, Kozak I, Shang Q, Ma J. Novel observations in choroidal osteoma by multispectral imaging: a pilot case series. Int Ophthalmol 2020; 40:3413-3430. [PMID: 32734445 DOI: 10.1007/s10792-020-01528-9] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2020] [Accepted: 07/20/2020] [Indexed: 12/01/2022]
Abstract
PURPOSE To identify novel tumor-specific features of ossification by using multispectral imaging (MSI) in patients diagnosed with choroidal osteoma. METHODS Six eyes of 5 patients previously diagnosed with choroidal osteoma by ocular ultrasonography and orbital computerized tomography were observed with multispectral imaging (MSI). Traditional multimodal imaging, including color fundus photograph (CFP) and enhanced depth-imaging-optical coherence tomography (EDI-OCT), fundus autofluorescence (FAF), indocyanine green angiography/fundus fluorescein angiography (ICGA/FFA), was performed. Osseous features detected by MSI such as calcification and decalcification were characterized and compared with other imaging modalities. RESULTS In all 3 eyes with calcified choroidal osteoma (100%), MSI featured by the homogeneous reflectance in 550 nm but the beehive appearance in 600-680 nm and homogenous hyper-reflectance in 780-850 nm', indicating the compact bone in the outer layers and bone trabecula in the middle layer (Sandwich sign). The pigmentary change showed high agreement between MSI and FAF. In other 3 eyes with extensive decalcification, MSI was able to differentiate the inactive portion of the osteoma from the decalcified area. The inactive portion was characterized by geographic hyper-reflective islands with higher reflectivity border (floating island sign). Decalcified portion was featured by increased definition and reflectivity from osteoma. Partial decalcification and total decalcification can be differentiated in one decalcifying eye (33.3%). MSI revealed better the presence and border of the osteoma compared with FFA, FAF and MC (100%) in all six eyes in our study. CONCLUSIONS MSI presented characteristic osseous-related features of choroidal osteoma, providing clear evidence for differentiating osteoblastic and osteoclastic regions and noncalcifying regions. It can contribute to en-face visualization of choroidal osteomas at different stages, providing new insight into the spectrum behavior of CO.
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Affiliation(s)
- Feiyan Ma
- Department of Ophthalmology, The Second Hospital of Hebei Medical University, Shijiazhaung, 050000, Hebei Province, China
| | - Tianhang Li
- Department of Ophthalmology, The Second Hospital of Hebei Medical University, Shijiazhaung, 050000, Hebei Province, China
| | - Igor Kozak
- Moorfields Eye Hospitals UAE, Abu Dhabi, United Arab Emirates
| | - Qingli Shang
- Department of Ophthalmology, The Second Hospital of Hebei Medical University, Shijiazhaung, 050000, Hebei Province, China.
| | - Jingxue Ma
- Department of Ophthalmology, The Second Hospital of Hebei Medical University, Shijiazhaung, 050000, Hebei Province, China.
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Subclinical Retinal versus Brain Findings in Infants with Hypoxic Ischemic Encephalopathy. Graefes Arch Clin Exp Ophthalmol 2020; 258:2039-2049. [PMID: 32472201 DOI: 10.1007/s00417-020-04738-0] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2020] [Revised: 04/28/2020] [Accepted: 05/06/2020] [Indexed: 12/19/2022] Open
Abstract
PURPOSE To detect retinal features and abnormalities on optical coherence tomography (OCT) without pupil dilation and relate these to brain injury in infants with a clinical diagnosis of hypoxic ischemic encephalopathy (HIE). METHODS Under an institutional review board-approved protocol, we imaged eight infants without pharmacologic mydriasis, using handheld, non-contact spectral-domain (Leica Microsystems, IL) or investigational swept-source OCT at the bedside in an intensive care nursery, after birth (depending on primary clinical care team permission based on health status) and weekly until discharge. The newborn infant with HIE is neurologically unstable; therefore, pharmacologic mydriasis and stimulation with visible light for retinal examination are usually avoided. We analyzed images for retinal pathologies, central foveal thickness, and retinal nerve fiber layer (RNFL) thickness at the papillomacular bundle and compared them to historical controls and published normative data, HIE clinical assessment, and abnormalities on brain magnetic resonance imaging (MRI). RESULTS On OCT, three of eight infants had bilateral multiple small macular and perimacular cystoid spaces; two of these three infants also had pronounced retinal ganglion cell layer thinning and severe brain injury on MRI and the third had bilateral paracentral acute middle maculopathy and mild brain injury on MRI. Other findings in HIE infant eyes included abnormally thin fovea and thin RNFL and markers of retinal immaturity such as the absence of sub-foveal photoreceptor development and sub-foveal fluid. CONCLUSIONS Bedside handheld OCT imaging within the first 2 weeks of life revealed retinal injury in infants with HIE-related brain injury. Future studies may determine the relationship between acute/subacute retinal abnormalities and brain injury severity and neurodevelopmental outcomes in HIE.
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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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12
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Ophthalmic outcomes following neonatal hypoxic ischaemic encephalopathy; oculomotor, biometric and refractive data in early childhood. Eye (Lond) 2019; 33:1152-1157. [PMID: 30837711 DOI: 10.1038/s41433-019-0390-6] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2018] [Revised: 02/11/2019] [Accepted: 02/20/2019] [Indexed: 11/08/2022] Open
Abstract
OBJECTIVES To investigate the functional and structural impact of neonatal hypoxic ischaemic encephalopathy (HIE) on childhood visual development. METHODS In a prospective study, the neurocognitive outcomes of 42 children with a history of neonatal HIE were assessed serially up to 5 years. For the ophthalmic component of the study, visual, refractive, orthoptic and ocular biometry measurements were obtained in 32 children, with axial length measurements estimated using the IOLMaster. RESULTS For the 32 children who completed the ophthalmic component of the study, severity of HIE grade was determined to be mild, moderate, or severe in 18 (56.3%), 13 (40.6%), and 1 (3.1%) cases, respectively. One (3.1%) child was classed as visually impaired. Twelve (37.5%) were found to have ametropia. Mean (±SD) axial length was 22.09 (±0.81) mm, within the normal range for the age of this cohort. Seven of the 42 (16.7%) children who were involved in the larger neurodevelopmental arm of the study had clinical evidence of a squint. There was no correlation between the severity of HIE grade at birth and axial length or occurrence of squint. CONCLUSIONS Neonatal HIE is associated with a higher incidence of squint compared with the general paediatric population. This occurred irrespective of severity of HIE grade. The ocular biometry measurements were consistent with published normative data, and no significant difference in ocular biometry was demonstrated between HIE severity groups.
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δ-Opioid Receptor-Nrf-2-Mediated Inhibition of Inflammatory Cytokines in Neonatal Hypoxic-Ischemic Encephalopathy. Mol Neurobiol 2018; 56:5229-5240. [PMID: 30560518 DOI: 10.1007/s12035-018-1452-7] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2018] [Accepted: 12/07/2018] [Indexed: 12/11/2022]
Abstract
Neonatal hypoxic-ischemic encephalopathy (HIE) causes serious neurological disability; there are, however, currently few promising therapies for it. We have recently shown that δ-opioid receptor (DOR) is neuroprotective by downregulating TNF-α. Since hypoxia-ischemia (HI) triggers a robust inflammatory response, which exacerbates HI brain damage, we investigated, in this study, whether DOR activation could regulate inflammatory cytokine expression, thereby playing a protective effect on the neonatal brain under HI. Twenty-five neonatal rats were randomly divided into five groups: (1) control (control); (2) HI; (3) HI with saline (HI + NS); (4) DOR activation with UFP-512 (a potent and specific DOR agonist) under HI conditions (HI + U); and (5) DOR inhibition using NT treatment under HI conditions (HI + NT). The rats were sacrificed by decapitation at 24 h after HI, and their brains were rapidly removed for measurements. The protein expression of TNF-α, IL-6, ICAM-1, IL-10, IL-18, NQO-1, Nrf-2, and HO-1 was measured using Western blot. In the hemispheres exposed to HI, DOR activation significantly decreased the expressions of TNF-α, IL-6, and ICAM-1 in the cortex, while it significantly increased IL-10 and had no effect on IL-18 in the same region. In contrast, DOR had no appreciable effect on inflammatory cytokine expression in non-cortical tissues including hippocampal, subcortical, and cerebellar tissues. Moreover, HI stress triggered an upregulation of Nrf-2 nuclear protein as well as some of its downstream anti-inflammatory genes such as HO-1 and NQO-1 in the cortex, while DOR activation further augmented such a protective reaction against HI injury. DOR plays an important role in protecting against HI by regulating the expression of inflammatory and anti-inflammatory cytokines in the cortex, which is likely mediated by the Nrf-2/HO-1/NQO-1 signaling.
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14
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Dumanska H, Veselovsky N. Short-term hypoxia induces bidirectional pathological long-term plasticity of neurotransmission in visual retinocollicular pathway. Exp Eye Res 2018; 179:25-31. [PMID: 30393125 DOI: 10.1016/j.exer.2018.10.014] [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: 08/10/2018] [Revised: 10/16/2018] [Accepted: 10/22/2018] [Indexed: 10/28/2022]
Abstract
Using the paired patch-clamp technique, we studied the effects of short-term hypoxia on retinocollicular synaptic transmission in an originally-developed coculture of dissociated retinal cells and superficial superior colliculus (SSC) neurons. Pharmacologically isolated N-methyl-D-aspartate receptor (NMDA)-, α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptor (AMPA)- and gamma-aminobutyric acid receptor (GABAA)-mediated postsynaptic currents (PSCs) were evoked in SSC neurons by generation action potentials in presynaptic retinal ganglion cells. Spontaneous and miniature PSCs were recorded in SSC neurons in the absence of presynaptic stimulation. Short-term (up to 5 min) hypoxia induced long-term potentiation of NMDA transmission, long-term depression of GABAA neurotransmission and temporary suppression of AMPA transmission. Also, we observed hypoxia-induced reduction of voltage-dependent magnesium blockade of evoked NMDA response. Evoked, spontaneous and miniature postsynaptic currents were analyzed in terms of a binomial model. This analysis revealed that hypoxia acts mainly presynaptically on excitatory neurotransmission and both pre‒ and postsynaptically on inhibitory retinocollicular transmission. Thus, we showed for the first time hypoxia-induced bidirectional long-term plasticity of the retinocollicular synaptic transmission. The results obtained reflect the electrophysiological basis of hypoxia-involved pathological lesion of the retinocollicular pathway.
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Affiliation(s)
- Hanna Dumanska
- Bogomoletz Institute of Physiology, National Academy of Sciences of Ukraine, Department of Neuronal Networks Physiology, 4 Bogomoletz Street, Kyiv, 01024, Ukraine.
| | - Nickolai Veselovsky
- Bogomoletz Institute of Physiology, National Academy of Sciences of Ukraine, Department of Neuronal Networks Physiology, 4 Bogomoletz Street, Kyiv, 01024, Ukraine.
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15
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Smith NM, Giacci MK, Gough A, Bailey C, McGonigle T, Black AMB, Clarke TO, Bartlett CA, Swaminathan Iyer K, Dunlop SA, Fitzgerald M. Inflammation and blood-brain barrier breach remote from the primary injury following neurotrauma. J Neuroinflammation 2018; 15:201. [PMID: 29981582 PMCID: PMC6035802 DOI: 10.1186/s12974-018-1227-0] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2018] [Accepted: 06/15/2018] [Indexed: 01/09/2023] Open
Abstract
BACKGROUND Following injury to the central nervous system, increased microglia, secretion of pro- and anti-inflammatory cytokines, and altered blood-brain barrier permeability, a hallmark of degeneration, are observed at and immediately adjacent to the injury site. However, few studies investigate how regions remote from the primary injury could also suffer from inflammation and secondary degeneration. METHODS Adult female Piebald-Viral-Glaxo (PVG) rats underwent partial transection of the right optic nerve, with normal, age-matched, unoperated animals as controls. Perfusion-fixed brains and right optic nerves were harvested for immunohistochemical assessment of inflammatory markers and blood-brain barrier integrity; fresh-frozen brains were used for multiplex cytokine analysis. RESULTS Immediately ventral to the optic nerve injury, immunointensity of both the pro-inflammatory biomarker inducible nitric oxide synthase (iNOS) and the anti-inflammatory biomarker arginase-1 (Arg1) increased at 7 days post-injury, with colocalization of iNOS and Arg1 immunoreactivity within individual cells. CD11b+ and CD45+ cells were increased 7 days post-injury, with altered BBB permeability still evident at this time. In the lower and middle optic tract and superior colliculus, IBA1+ resident microglia were first increased at 3 days; ED1+ and CD11b+ cells were first increased in the middle and upper tract and superior colliculus 7 days post-injury. Increased fibrinogen immunoreactivity indicative of altered BBB permeability was first observed in the contralateral upper tract at 3 days and middle tract at 7 days post-injury. Multiplex cytokine analysis of brain homogenates indicated significant increases in the pro-inflammatory cytokines, IL-2 and TNFα, and anti-inflammatory cytokine IL-10 1 day post-injury, decreasing to control levels at 3 days for TNFα and 7 days for IL-2. IL-10 was significantly elevated at 1 and 7 days post-injury with a dip at 3 days post-injury. CONCLUSIONS Partial injury to the optic nerve induces a complex remote inflammatory response, characterized by rapidly increased pro- and anti-inflammatory cytokines in brain homogenates, increased numbers of IBA1+ cells throughout the visual pathways, and increased CD11b+ and ED1+ inflammatory cells, particularly towards the synaptic terminals. BBB permeability can increase prior to inflammatory cell infiltration, dependent on the brain region.
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Affiliation(s)
- Nicole M Smith
- School of Molecular Sciences, The University of Western Australia, Stirling Hwy, Perth, Western Australia, 6009, Australia
| | - Marcus K Giacci
- Experimental and Regenerative Neurosciences, School of Biological Sciences, The University of Western Australia, Stirling Hwy, Perth, Western Australia, 6009, Australia
| | - Alexander Gough
- Experimental and Regenerative Neurosciences, School of Biological Sciences, The University of Western Australia, Stirling Hwy, Perth, Western Australia, 6009, Australia
| | - Charlotte Bailey
- School of Molecular Sciences, The University of Western Australia, Stirling Hwy, Perth, Western Australia, 6009, Australia
| | - Terence McGonigle
- Curtin Health Innovation Research Institute, Curtin University, Verdun St, Nedlands, Western Australia, Australia
| | - Anna M B Black
- Curtin Health Innovation Research Institute, Curtin University, Verdun St, Nedlands, Western Australia, Australia
| | - Thomas O Clarke
- Curtin Health Innovation Research Institute, Curtin University, Verdun St, Nedlands, Western Australia, Australia
| | - Carole A Bartlett
- Experimental and Regenerative Neurosciences, School of Biological Sciences, The University of Western Australia, Stirling Hwy, Perth, Western Australia, 6009, Australia.,Curtin Health Innovation Research Institute, Curtin University, Verdun St, Nedlands, Western Australia, Australia
| | - K Swaminathan Iyer
- School of Molecular Sciences, The University of Western Australia, Stirling Hwy, Perth, Western Australia, 6009, Australia
| | - Sarah A Dunlop
- Experimental and Regenerative Neurosciences, School of Biological Sciences, The University of Western Australia, Stirling Hwy, Perth, Western Australia, 6009, Australia
| | - Melinda Fitzgerald
- Experimental and Regenerative Neurosciences, School of Biological Sciences, The University of Western Australia, Stirling Hwy, Perth, Western Australia, 6009, Australia. .,Curtin Health Innovation Research Institute, Curtin University, Verdun St, Nedlands, Western Australia, Australia. .,Perron Institute for Neurological and Translational Science, Sarich Neuroscience Research Institute, Verdun St, Nedlands, Western Australia, 6009, Australia.
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16
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Li D, Li S, Zeng X. Analysis of alterations in white matter integrity of adult patients with comitant exotropia. J Int Med Res 2018; 46:1963-1972. [PMID: 29569963 PMCID: PMC5991243 DOI: 10.1177/0300060518763704] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Objective This study was performed to investigate structural abnormalities of the white matter in patients with comitant exotropia using the tract-based spatial statistics (TBSS) method. Methods Diffusion tensor imaging data from magnetic resonance images of the brain were collected from 20 patients with comitant exotropia and 20 age- and sex-matched healthy controls. The FMRIB Software Library was used to compute the diffusion measures, including fractional anisotropy (FA), mean diffusivity (MD), axial diffusivity (AD), and radial diffusivity (RD). These measures were obtained using voxel-wise statistics with threshold-free cluster enhancement. Results The FA values in the right inferior fronto-occipital fasciculus (IFO) and right inferior longitudinal fasciculus were significantly higher and the RD values in the bilateral IFO, forceps minor, left anterior corona radiata, and left anterior thalamic radiation were significantly lower in the comitant exotropia group than in the healthy controls. No significant differences in the MD or AD values were found between the two groups. Conclusions Alterations in FA and RD values may indicate the underlying neuropathologic mechanism of comitant exotropia. The TBSS method can be a useful tool to investigate neuronal tract participation in patients with this disease.
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Affiliation(s)
- Dan Li
- Department of Radiology, The 117970 First Affiliated Hospital of Nanchang University , Nanchang, Jiangxi Province, China
| | - Shenghong Li
- Department of Radiology, The 117970 First Affiliated Hospital of Nanchang University , Nanchang, Jiangxi Province, China
| | - Xianjun Zeng
- Department of Radiology, The 117970 First Affiliated Hospital of Nanchang University , Nanchang, Jiangxi Province, China
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17
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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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18
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Li L, Yuan Y, Chen L, Li M, Ji P, Gong J, Zhao Y, Zhang H. Gadolinium-enhanced 7.0 T magnetic resonance imaging assessment of the aqueous inflow in rat eyes in vivo. Exp Eye Res 2017; 162:18-26. [DOI: 10.1016/j.exer.2017.06.019] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2016] [Revised: 06/23/2017] [Accepted: 06/23/2017] [Indexed: 01/09/2023]
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19
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Magnetic resonance imaging study of eye congenital birth defects in mouse model. Mol Vis 2017; 23:572-578. [PMID: 28848319 PMCID: PMC5561137] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2017] [Accepted: 08/08/2017] [Indexed: 12/02/2022] Open
Abstract
PURPOSE Embryonic eyelid closure is a well-documented morphogenetic episode in mammalian eye development. Detection of eyelid closure defect in humans is a major challenge because eyelid closure and reopen occur entirely in utero. As a consequence, congenital eye defects that are associated with failure of embryonic eyelid closure remain unknown. To fill the gap, we developed a mouse model of defective eyelid closure. This preliminary work demonstrates that the magnetic resonance imaging (MRI) approach can be used for the detection of extraocular muscle abnormalities in the mouse model. METHODS Mice with either normal (Map3k1+/- ) or defective (Map3k1-/- ) embryonic eyelid closure were used in this study. Images of the extraocular muscles were obtained with a 9.4 T high resolution microimaging MRI system. The extraocular muscles were identified, segmented, and measured in each imaging slice using an in-house program. RESULTS In agreement with histological findings, the imaging data show that mice with defective embryonic eyelid closure develop less extraocular muscle than normal mice. In addition, the size of the eyeballs was noticeably reduced in mice with defective embryonic eyelid closure. CONCLUSIONS We demonstrated that MRI can potentially be used for the study of extraocular muscle in the mouse model of the eye open-at-birth defect, despite the lack of specificity of muscle group provided by the current imaging resolution.
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20
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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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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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Diaz R, Miguel PM, Deniz BF, Confortim HD, Barbosa S, Mendonça MCP, Cruz‐Höfling MA, Pereira LO. Environmental enrichment attenuates the blood brain barrier dysfunction induced by the neonatal hypoxia‐ischemia. Int J Dev Neurosci 2016; 53:35-45. [DOI: 10.1016/j.ijdevneu.2016.06.006] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2016] [Revised: 06/08/2016] [Accepted: 06/16/2016] [Indexed: 12/27/2022] Open
Affiliation(s)
- Ramiro Diaz
- Programa de Pós Graduação em NeurociênciasUniversidade Federal do Rio Grande do SulPorto AlegreRSBrazil
| | - Patrícia Maidana Miguel
- Programa de Pós Graduação em NeurociênciasUniversidade Federal do Rio Grande do SulPorto AlegreRSBrazil
| | - Bruna Ferrary Deniz
- Programa de Pós Graduação em NeurociênciasUniversidade Federal do Rio Grande do SulPorto AlegreRSBrazil
| | - Heloísa Deola Confortim
- Programa de Pós Graduação em NeurociênciasUniversidade Federal do Rio Grande do SulPorto AlegreRSBrazil
| | - Sílvia Barbosa
- Programa de Pós Graduação em NeurociênciasUniversidade Federal do Rio Grande do SulPorto AlegreRSBrazil
- Departamento de Ciências MorfológicasUniversidade Federal do Rio Grande do SulPorto AlegreRSBrazil
| | - Monique Culturato Padilha Mendonça
- Departamento de Farmacologia, Faculdade de Ciências MédicasUniversidade Estadual de Campinas (UNICAMP)CampinasSPBrazil
- Departamento de Bioquímica e Biologia TecidualInstituto de Biologia (IB), Universidade Estadual de Campinas (UNICAMP)CampinasSPBrazil
| | - Maria Alice Cruz‐Höfling
- Departamento de Farmacologia, Faculdade de Ciências MédicasUniversidade Estadual de Campinas (UNICAMP)CampinasSPBrazil
- Departamento de Bioquímica e Biologia TecidualInstituto de Biologia (IB), Universidade Estadual de Campinas (UNICAMP)CampinasSPBrazil
| | - Lenir Orlandi Pereira
- Programa de Pós Graduação em NeurociênciasUniversidade Federal do Rio Grande do SulPorto AlegreRSBrazil
- Departamento de Ciências MorfológicasUniversidade Federal do Rio Grande do SulPorto AlegreRSBrazil
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24
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Etminan M. Risk of intracranial hypertension with intrauterine levonorgestrel: reply. Ther Adv Drug Saf 2016; 7:25-6. [PMID: 26834961 DOI: 10.1177/2042098615621264] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Affiliation(s)
- Mahyar Etminan
- Therapeutic Evaluation Unit, Child & Family Research Institute of British Columbia, Faculty of Medicine, University of British Columbia, A4-198 WS 2, 709-650 West 28 Avenue, Vancouver, BC, Canada
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25
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Jung WB, Im GH, Chung JJ, Ahn SY, Jeon TY, Chang YS, Park WS, Kim JH, Kim KS, Lee JH. Neuroplasticity for spontaneous functional recovery after neonatal hypoxic ischemic brain injury in rats observed by functional MRI and diffusion tensor imaging. Neuroimage 2015; 126:140-50. [PMID: 26589335 DOI: 10.1016/j.neuroimage.2015.11.032] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2015] [Revised: 11/09/2015] [Accepted: 11/13/2015] [Indexed: 01/24/2023] Open
Abstract
For infants and children, an incredible resilience from injury is often observed. There is growing evidence that functional recovery after brain injury might well be a consequence of the reorganization of the neural network as a process of neuroplasticity. We demonstrate the presence of neuroplasticity at work in spontaneous recovery after neonatal hypoxic ischemic (HI) injury, by elucidating a precise picture in which such reorganization takes place using functional MRI techniques. For all 12 siblings, 6 rats were subjected to severe HI brain injury and 6 rats underwent sham operation only. Severe HI brain injury was induced to postnatal day 7 (p7) Sprague-Dawley rats according to the Rice-Vannucci model (right carotid artery occlusion followed by 150min of hypoxia with 8% O2 and 92% of N2). Brain activation maps along with anatomical and functional connectivity maps related to the sensory motor function were obtained at adult (p63) using blood oxygen level dependent (BOLD)-functional MRI (fMRI), resting state-functional MRI (rs-fMRI) and diffusion tensor imaging (DTI); each of these MRI data was related to sensory motor functional outcome. In-depth investigation of the functional MRI data revealed: 1) intra-hemispheric expansion of BOLD signal activation in the contralesional undamaged hemisphere for ipsilesional forepaw stimuli to include the M2 and Cg1 in addition to the S1 and M1 wide spreading in the anterior and posterior directions, 2) inter-hemispheric transfer of BOLD signal activation for contralesional forepaw stimuli, normally routed to the injured hemisphere, to analogous sites in the contralesional undamaged hemisphere, localized newly to the M1 and M2 with a reduced portion of the S1, 3) inter-hemispheric axonal disconnection and axonal rewiring within the undamaged hemisphere as shown through DTI, and 4) increased functional interactions within the cingulate gyrus in the HI injured rats as shown through rs-fMRI. The BOLD signal amplitudes as well as DTI and rs-fMRI data well correlate with behavioral tests (tape to remove). We found that function normally utilizing what would be the injured hemisphere is transferred to the uninjured hemisphere, and functionality of the uninjured hemisphere remains not untouched but is also rewired in an expansion corresponding to the newly formed sensorimotor function from both the contralesional and the ipsilesional sides. The conclusion drawn from the data in our current study is that enhanced motor function in the contralesional hemisphere governs both the normal and damaged sides, indicating that active plasticity with brain laterality was spontaneously generated to overcome functional loss and established autonomously through normal experience via modification of neural circuitry for neonatal HI injured brain.
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Affiliation(s)
- Won-Beom Jung
- Department of Radiology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul 06351, South Korea; Department of Global Biomedical Engineering, Sungkyunkwan University, Suwon 16419, South Korea
| | - Geun Ho Im
- Center for Molecular and Cellular Imaging, Samsung Biomedical Research Institute, Seoul 06351, South Korea
| | - Julius Juhyun Chung
- Department of Radiology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul 06351, South Korea; Samsung Advanced Institute of Health Science and Technology, Sungkyunkwan University, Seoul 06351, South Korea
| | - So-Yoon Ahn
- Department of Pediatrics Division of Neonatology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul 06351, South Korea
| | - Tae Yeon Jeon
- Department of Radiology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul 06351, South Korea
| | - Yun Sil Chang
- Samsung Advanced Institute of Health Science and Technology, Sungkyunkwan University, Seoul 06351, South Korea; Department of Pediatrics Division of Neonatology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul 06351, South Korea
| | - Won Soon Park
- Department of Pediatrics Division of Neonatology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul 06351, South Korea
| | - Ji Hye Kim
- Department of Radiology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul 06351, South Korea
| | - Ki-Soo Kim
- Department of Pediatrics Division of Neonatology, Asan Medical Center, University of Ulsan School of Medicine, Seoul 05535, South Korea
| | - Jung Hee Lee
- Department of Radiology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul 06351, South Korea; Department of Global Biomedical Engineering, Sungkyunkwan University, Suwon 16419, South Korea; Samsung Advanced Institute of Health Science and Technology, Sungkyunkwan University, Seoul 06351, South Korea.
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26
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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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27
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Altered contralateral sensorimotor system organization after experimental hemispherectomy: a structural and functional connectivity study. J Cereb Blood Flow Metab 2015; 35:1358-67. [PMID: 25966942 PMCID: PMC4527994 DOI: 10.1038/jcbfm.2015.101] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/27/2014] [Accepted: 04/10/2015] [Indexed: 12/18/2022]
Abstract
Hemispherectomy is often followed by remarkable recovery of cognitive and motor functions. This reflects plastic capacities of the remaining hemisphere, involving large-scale structural and functional adaptations. Better understanding of these adaptations may (1) provide new insights in the neuronal configuration and rewiring that underlies sensorimotor outcome restoration, and (2) guide development of rehabilitation strategies to enhance recovery after hemispheric lesioning. We assessed brain structure and function in a hemispherectomy model. With MRI we mapped changes in white matter structural integrity and gray matter functional connectivity in eight hemispherectomized rats, compared with 12 controls. Behavioral testing involved sensorimotor performance scoring. Diffusion tensor imaging and resting-state functional magnetic resonance imaging were acquired 7 and 49 days post surgery. Hemispherectomy caused significant sensorimotor deficits that largely recovered within 2 weeks. During the recovery period, fractional anisotropy was maintained and white matter volume and axial diffusivity increased in the contralateral cerebral peduncle, suggestive of preserved or improved white matter integrity despite overall reduced white matter volume. This was accompanied by functional adaptations in the contralateral sensorimotor network. The observed white matter modifications and reorganization of functional network regions may provide handles for rehabilitation strategies improving functional recovery following large lesions.
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28
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Li Q, Zhai L, Jiang Q, Qin W, Li Q, Yin X, Guo M. Tract-based spatial statistics analysis of white matter changes in children with anisometropic amblyopia. Neurosci Lett 2015; 597:7-12. [PMID: 25899779 DOI: 10.1016/j.neulet.2015.04.027] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2015] [Revised: 04/15/2015] [Accepted: 04/16/2015] [Indexed: 10/23/2022]
Abstract
Amblyopia is a neurological disorder of vision that follows abnormal binocular interaction or visual deprivation during early life. Previous studies have reported multiple functional or structural cortical alterations. Although white matter was also studied, it still cannot be clarified clearly which fasciculus was affected by amblyopia. In the present study, tract-based spatial statistics analysis was applied to diffusion tensor imaging (DTI) to investigate potential diffusion changes of neural tracts in anisometropic amblyopia. Fractional anisotropy (FA) value was calculated and compared between 20 amblyopic children and 18 healthy age-matched controls. In contrast to the controls, significant decreases in FA values were found in right optic radiation (OR), left inferior longitudinal fasciculus/inferior fronto-occipital fasciculus (ILF/IFO) and right superior longitudinal fasciculus (SLF) in the amblyopia. Furthermore, FA values of these identified tracts showed positive correlation with visual acuity. It can be inferred that abnormal visual input not only hinders OR from well developed, but also impairs fasciculi associated with dorsal and ventral visual pathways, which may be responsible for the amblyopic deficiency in object discrimination and stereopsis. Increased FA was detected in right posterior part of corpus callosum (CC) with a medium effect size, which may be due to compensation effect. DTI with subsequent measurement of FA is a useful tool for investigating neuronal tract involvement in amblyopia.
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Affiliation(s)
- Qian Li
- Department of Radiology, Tianjin Medical University Cancer Institute and Hospital, National Clinical Research Center of Cancer, Key Laboratory of Cancer Prevention and Therapy, Tianjin, China
| | - Liying Zhai
- School of Medical Imaging, Tianjin Medical University, Tianjin, China
| | - Qinying Jiang
- School of Medical Imaging, Tianjin Medical University, Tianjin, China; Institute of Neuroscience, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai, China
| | - Wen Qin
- Department of Radiology, Tianjin Medical University General Hospital, Tianjin, China
| | - Qingji Li
- Department of Pediatric Strabismus and Amblyopia, Tianjin Aier Ophthalmology Hospital, Tianjin, China
| | - Xiaohui Yin
- Department of Radiology, Tianjin Medical University General Hospital, Tianjin, China
| | - Mingxia Guo
- School of Medical Imaging, Tianjin Medical University, Tianjin, China.
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