Reduced hippocampal manganese-enhanced MRI (MEMRI) signal during pilocarpine-induced status epilepticus: Edema or apoptosis?

Reduced hippocampal manganese-enhanced MRI (MEMRI) signal during pilocarpine-induced status epilepticus: Edema or apoptosis?

Author Malheiros, Jackeline Moraes Autor UNIFESP Google Scholar
Persike, Daniele Suzete Autor UNIFESP Google Scholar
Cardoso de Castro, Leticia Urbana Google Scholar
Cunha Sanches, Talita Rojas Google Scholar
Andrade, Lucia da Conceicao Google Scholar
Tannus, Alberto Google Scholar
Covolan, Luciene Autor UNIFESP Google Scholar
Institution Universidade Federal de São Paulo (UNIFESP)
Universidade de São Paulo (USP)
Abstract Manganese-enhanced MRI (MEMRI) has been considered a surrogate marker of Ca+2 influx into activated cells and tracer of neuronal active circuits. However, the induction of status epilepticus (SE) by kainic acid does not result in hippocampal MEMRI hypersignal, in spite of its high cell activity. Similarly, short durations of status (5 or 15 min) induced by pilocarpine did not alter the hippocampal MEMRI, while 30 min of SE even reduced MEMRI signal Thus, this study was designed to investigate possible explanations for the absence or decrease of MEMRI signal after short periods of SE. We analyzed hippocampal caspase-3 activation (to evaluate apoptosis), T-2 relaxometry (tissue water content) and aquaporin 4 expression (water-channel protein) of rats subjected to short periods of pilocarpine-induced SE. for the time periods studied here, apoptotic cell death did not contribute to the decrease of the hippocampal MEMRI signal. However, T-2 relaxation was higher in the group of animals subjected to 30 min of SE than in the other SE or control groups. This result is consistent with higher AQP-4 expression during the same time period. Based on apoptosis and tissue water content analysis, the low hippocampal MEMRI signal 30 min after SE can potentially be attributed to local edema rather than to cell death. (C) 2014 Elsevier B.V. All rights reserved.
Keywords Pilocarpine
Epilepsy
Manganese-enhanced magnetic resonance imaging
Edema
Apoptosis
Hippocampus
Language English
Sponsor Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
Grant number FAPESP: 05/56663-1
FAPESP: 07/52911-6
Date 2014-05-01
Published in Epilepsy Research. Amsterdam: Elsevier B.V., v. 108, n. 4, p. 644-652, 2014.
ISSN 0920-1211 (Sherpa/Romeo, impact factor)
Publisher Elsevier B.V.
Extent 644-652
Origin http://dx.doi.org/10.1016/j.eplepsyres.2014.02.007
Access rights Closed access
Type Article
Web of Science ID WOS:000335623100005
URI http://repositorio.unifesp.br/handle/11600/37730

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