Aquaporin-4 expression is increased in oedematous human brain tumours

J Neurol Neurosurg Psychiatry. 2002 Feb;72(2):262-5. doi: 10.1136/jnnp.72.2.262.


Aquaporin-4 (AQP4) is a highly conserved water channel protein. In rats, AQP4 is expressed in astrocyte foot processes and is important in brain water homeostasis. AQP4 expression has not been investigated in non-neoplastic human brain or oedematous brain tumours, where water homeostasis is disrupted. Therefore, immunohistochemistry was used to study AQP4 expression in non-neoplastic and neoplastic human brain and blood-brain barrier permeability was assessed using contrast enhanced computed tomograms. AQP4 was present around microvessels in five specimens of non-neoplastic brain and five low grade (Daumas-Duport I or II) astrocytomas. AQP4 was massively upregulated in four and absent in one high grade (Daumas-Duport III or IV) astrocytoma. Massive upregulation of AQP4 was also found in reactive astrocytes in five metastatic adenocarcinomas. There was significant (p<0.0001) correlation between blood-brain barrier opening and upregulated AQP4 expression. Increased AQP4 expression in high grade astrocytomas and adenocarcinomas may facilitate the flow of oedema fluid.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adenocarcinoma / pathology
  • Adenocarcinoma / secondary
  • Adult
  • Aged
  • Aquaporin 4
  • Aquaporins / analysis*
  • Astrocytes / pathology
  • Astrocytoma / pathology*
  • Blood-Brain Barrier / physiology
  • Brain / pathology
  • Brain Edema / pathology*
  • Brain Neoplasms / pathology*
  • Brain Neoplasms / secondary
  • Capillary Permeability / physiology
  • Female
  • Glial Fibrillary Acidic Protein / analysis
  • Humans
  • Male
  • Microcirculation / pathology
  • Middle Aged
  • Water-Electrolyte Balance / physiology


  • AQP4 protein, human
  • Aquaporin 4
  • Aquaporins
  • Glial Fibrillary Acidic Protein