Statin-induced T-lymphocyte modulation and neuroprotection following experimental subarachnoid hemorrhage

Robert E. Ayer, Robert P. Ostrowski, Takashi Sugawara, Qingy Ma, Nazanin Jafarian, Jiping Tang, John H. Zhang

Research output: Chapter in Book/Report/Conference proceedingConference contribution

Abstract

Introduction: Statins influence immune system activities through mechanisms independent of their lipid-lowering properties. T cells can be subdivided based on cytokine secretion patterns into two subsets: T-helper cells type 1 (Th1) and type 2 (Th2). Independent laboratory studies have shown statins to be potent inducers of a Th2 switch in immune cell response and be neuroprotective in several models of central nervous system (CNS) disease. This study was the first to evaluate the immune modulating effects of statins in subarachnoid hemorrhage (SAH). Methods: Simvastatin was administered to rats intraperitoneally in two dosages (1 and 20 mg/kg) 30 min after the induction of SAH using endovascular perforation. Neurological scores were assessed 24 h later. Animals were then sacrificed, and samples of cortex and brain stem were tested for expression of the T-regulatory cell cytokine transforming growth factor (TGF) β1, as well as interleukin (IL) 1β, a proinflammatory cytokine associated with Th1 immune responses. The presence of TGF-β1 secreting T cells was evaluated with the use of brain slices. Results: SAH significantly impaired neurological function in all SAH groups (treated and untreated) versus sham. Animals treated with high-dose simvastatin had less neurological impairment than both untreated and low-dose groups. Cortical and brain-stem levels of TGF-β1 were significantly elevated following SAH in the high-dose group. IL-1β was significantly elevated following the induction of SAH but was inhibited by high-dose simvastatin. Double-labeled fluorescent immunohistochemical data demonstrated the presence of lymphocytes in the subarachnoid and perivascular spaces following SAH. Expression of TGF-β1 by lymphocytes was markedly increased following treatment with high-dose simvastatin. Conclusion: The present study elucidated the potential role of a Th2 immune switch in statin provided neuroprotection following SAH.

Original languageEnglish
Title of host publicationCerebral Vasospasm
Subtitle of host publicationNeurovascular Events After Subarachnoid Hemorrhage
PublisherSpringer-Verlag Wien
Pages259-266
Number of pages8
ISBN (Print)9783709111918
DOIs
StatePublished - 2013

Publication series

NameActa Neurochirurgica, Supplementum
Volume115
ISSN (Print)0065-1419
ISSN (Electronic)0001-6268

ASJC Scopus Subject Areas

  • Surgery
  • Clinical Neurology

Keywords

  • Early brain injury
  • Endovascular perforation model
  • Simvastatin
  • Subarachnoid hemorrhage
  • TGF-β1
  • Th2 lymphocytes
  • Th3 lymphocytes

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