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Towner RA, Saunders D, Smith N, Towler W, Cruz M, Do S, Maher JE, Whitaker K, Lerner M, Morton KA. Assessing long-term neuroinflammatory responses to encephalopathy using MRI approaches in a rat endotoxemia model. GeroScience 2018; 40:49-60. [PMID: 29417380 PMCID: PMC5832664 DOI: 10.1007/s11357-018-0009-z] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2017] [Accepted: 01/30/2018] [Indexed: 02/08/2023] Open
Abstract
Sepsis-associated encephalopathy (SAE) induces neuroinflammation, which is associated with cognitive impairment (CI). CI is also correlated with aging. We used contrast-enhanced magnetic resonance imaging (MRI), perfusion MRI, and MR spectroscopy to assess long-term alterations in BBB permeability, microvascularity, and metabolism, respectively, in a rat lipopolysaccharide-induced SAE model. Free radical-targeted molecular MRI was used to detect brain radical levels at 24 h and 1 week post-LPS injection. CE-MRI showed increased Gd-DTPA uptake in LPS rat brains at 24 h in cerebral cortex, hippocampus, thalamus, and perirhinal cortex regions. Increased MRI signal intensities were observed in LPS rat brains in cerebral cortex, perirhinal cortex, and hippocampus regions 1 week post-LPS. Long-term BBB dysfunction was detected in the cerebral cortex at 6 weeks post-LPS. Increased relative cerebral blood flow (rCBF) in cortex and thalamus regions at 24 h, decreased cortical and hippocampal rCBF at 6 weeks, decreased cortical rCBF at 3 and 12 weeks, and increased thalamus rCBF at 6 weeks post-LPS, were detected. MRS indicated that LPS-exposed rat brains had decreased: NAA/Cho metabolite ratios at 1, 3, 6, and 12 weeks; Cr/Cho at 1, 3, and 12 weeks; and Myo-Ins/Cho at 1, 3, and 6 weeks post-LPS. Free radical imaging detected increased radical levels in LPS rat brains at 24 h and 1 week post-LPS. LPS-exposed rats were compared to saline-treated controls. We clearly demonstrated BBB dysfunction, impaired vascularity, and decreased brain metabolites, as measures of long-term neuroinflammatory indicators, as well as increased free radicals in a LPS-induced rat SAE model.
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Affiliation(s)
- Rheal A Towner
- Advanced Magnetic Resonance Center, Oklahoma Medical Research Foundation, 825 N.E. 13th Street, Oklahoma City, OK, 73104, USA.
- Oklahoma Nathan Shock Aging Center, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA.
- Oklahoma Center for Neuroscience, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA.
| | - D Saunders
- Advanced Magnetic Resonance Center, Oklahoma Medical Research Foundation, 825 N.E. 13th Street, Oklahoma City, OK, 73104, USA
| | - N Smith
- Advanced Magnetic Resonance Center, Oklahoma Medical Research Foundation, 825 N.E. 13th Street, Oklahoma City, OK, 73104, USA
| | - W Towler
- Advanced Magnetic Resonance Center, Oklahoma Medical Research Foundation, 825 N.E. 13th Street, Oklahoma City, OK, 73104, USA
| | - M Cruz
- Advanced Magnetic Resonance Center, Oklahoma Medical Research Foundation, 825 N.E. 13th Street, Oklahoma City, OK, 73104, USA
| | - S Do
- Advanced Magnetic Resonance Center, Oklahoma Medical Research Foundation, 825 N.E. 13th Street, Oklahoma City, OK, 73104, USA
| | - J E Maher
- Advanced Magnetic Resonance Center, Oklahoma Medical Research Foundation, 825 N.E. 13th Street, Oklahoma City, OK, 73104, USA
| | - K Whitaker
- Advanced Magnetic Resonance Center, Oklahoma Medical Research Foundation, 825 N.E. 13th Street, Oklahoma City, OK, 73104, USA
| | - M Lerner
- Department of Surgery Research Laboratory, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA
| | - K A Morton
- Department of Radiology and Imaging Sciences, University of Utah School of Medicine, Salt Lake City, UT, USA
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