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NMR Biomed. 2017 Jul;30(7). doi: 10.1002/nbm.3717. Epub 2017 Mar 8.

Sensitivity of diffusion MRI to perilesional reactive astrogliosis in focal ischemia.

Author information

1
Department of Neuroscience, Medical University of South Carolina, Charleston, SC, USA.
2
Department of Radiology and Radiological Science, Medical University of South Carolina, Charleston, SC, USA.
3
Center for Biomedical Imaging, Medical University of South Carolina, Charleston, SC, USA.
4
Department of Public Health Sciences, Medical University of South Carolina, Charleston, SC, USA.
5
Department of Diagnostic Radiology, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Pokfulam, Hong Kong, SAR, China.
6
Department of Health Science and Research, Medical University of South Carolina, Charleston, SC, USA.

Abstract

Reactive astrogliosis is a response to injury in the central nervous system that plays an essential role in inflammation and tissue repair. It is characterized by hypertrophy of astrocytes, alterations in astrocyte gene expression and astrocyte proliferation. Reactive astrogliosis occurs in multiple neuropathologies, including stroke, traumatic brain injury and Alzheimer's disease, and it has been proposed as a possible source of the changes in diffusion magnetic resonance imaging (dMRI) metrics observed with these diseases. In this study, the sensitivity of dMRI to reactive astrogliosis was tested in an animal model of focal acute and subacute ischemia induced by the vasoconstricting peptide, endothelin-1. Reactive astrogliosis in perilesional cortex was quantified by calculating the astrocyte surface density as determined with a glial fibrillary acidic protein (GFAP) antibody, whereas perilesional diffusion changes were measured in vivo with diffusional kurtosis imaging. We found substantial changes in the surface density of GFAP-positive astrocyte processes and modest changes in dMRI metrics in the perilesional motor cortex following stroke. Although there are time point-specific correlations between dMRI and histological measures, there is no definitive evidence for a causal relationship.

KEYWORDS:

GFAP; MRI; astrogliosis; diffusion; imaging; ischemia; perilesional; stereology

PMID:
28272771
PMCID:
PMC5759343
DOI:
10.1002/nbm.3717
[Indexed for MEDLINE]
Free PMC Article

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