TY - JOUR
T1 - Long-term effects of neonatal hypoxia-ischemia on structural and physiological integrity of the eye and visual pathway by multimodal MRI
AU - Chan, Kevin C.
AU - Kancherla, Swarupa
AU - Fan, Shu Juan
AU - Wu, Ed X.
N1 - Publisher Copyright:
© 2015 The Association for Research in Vision and Ophthalmology, Inc.
PY - 2015/12/9
Y1 - 2015/12/9
N2 - 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 hypoxiaischemia 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 hypoxicischemic 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.
AB - 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 hypoxiaischemia 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 hypoxicischemic 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.
KW - Contrast-enhanced MRI
KW - Diffusion tensor imaging
KW - Neonatal hypoxia-ischemia
KW - Ocular tissue permeability
KW - Visual pathway integrity
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U2 - 10.1167/iovs.14-14287
DO - 10.1167/iovs.14-14287
M3 - Article
C2 - 25491295
AN - SCOPUS:84921306130
SN - 0146-0404
VL - 56
SP - 1
EP - 9
JO - Investigative Ophthalmology and Visual Science
JF - Investigative Ophthalmology and Visual Science
IS - 1
ER -