Expression pattern of the water channel aquaporin-4 in human gliomas is associated with blood-brain barrier disturbance but not with patient survival

Arne Warth, Perikles Simon, David Capper, Benjamin Goeppert, Ghazaleh Tabatabai, Hajo Herzog, Klaus Dietz, Florian Stubenvoll, Rami Ajaaj, Ralf Becker, Michael Weller, Richard Meyermann, Hartwig Wolburg, Michel Mittelbronn*

*Corresponding author for this work

Research output: Contribution to journalArticleResearchpeer-review

111 Citations (Scopus)

Abstract

Aquaporin-4 (AQP4), the most prominent CNS water channel, is restricted to the glia limitans and astrocytic endfeet. We previously showed the loss of spatial AQP4 expression in glioblastomas and a redistribution across the cell surface. However, opposing AQP4 functions have been described: protective in vasogenic but detrimental in cytotoxic brain edema. Thus, specific AQP4 induction to prevent or reduce vasogenic edema is suggested. To elucidate the AQP4 role in brain tumors, we investigated 189 WHO grade I-IV gliomas by immunohistochemistry and the prognostic significance for patients' survival. In gliomas, a remarkable de novo AQP4 redistribution was observed in comparison with normal CNS tissue. Surprisingly, the highest membraneous staining levels were seen in pilocytic astrocytomas WHO grade I and grade IV glioblastomas, both significantly higher than in WHO grade II astrocytomas. AQP4 up-regulation was associated with brain edema formation; however, no association between survival and WHO grade-dependent AQP4 expression was seen. Hence, AQP4 redistribution may go along with other tumor properties, such as vascular proliferation and resulting blood-brain barrier disturbance, features usually prominent in pilocytic astrocytomas WHO I and glioblastomas WHO grade IV. In summary, our findings question the protective role of AQP4 in vasogenic brain edema. Although AQP4 was associated with brain edema formation, one has to question the suitability of AQP4 induction as a promising approach in vasogenic brain edema prevention and treatment. In addition, our results provide unexpectedly high AQP4 levels in pilocytic astrocytomas and present AQP4 as tumor progression marker in WHO grade II-IV astrocytomas.

Original languageEnglish
Pages (from-to)1336-1346
Number of pages11
JournalJournal of Neuroscience Research
Volume85
Issue number6
DOIs
Publication statusPublished - 1 May 2007
Externally publishedYes

Keywords

  • Aquaporin-4
  • Brain edema
  • Human glioma
  • Survival

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