title: Aquaporin-4 expression in the cerebrospinal fluid in congenital human hydrocephalus.
abstract: BACKGROUND
  Aquaporin-4 (AQP4) is a water channel mainly located in the ventricular ependymal cells (brain-CSF barrier), the sub-ependymal glia, glia limitans and in end-feet of astrocytes in at the blood-brain barrier (BBB).
  
  
  METHODS
  In the present work, the expression of AQP4 in the cerebrospinal fluid (CSF) in control and congenital human hydrocephalus infants (obstructive and communicating), was analysed by Western-blot and enzyme immunoassay (ELISA).
  
  
  RESULTS
  AQP4 was found to be high compared to the control in the CSF in congenital hydrocephalus patients. Western-blot showed higher values for AQP4 than controls in communicating hydrocephalus (communicating: 38.3%, control: 6.9% p < 0.05) although the increase was not significant in obstructive hydrocephalus (obstructive: 14.7%). The AQP4 quantification by ELISA also showed that, the mean concentration of AQP4 in CSF was significantly higher in communicating hydrocephalus (communicating: 11.32 ± 0.69 ng/ml, control: 8.61 ± 0.31 ng/ml; p < 0.05). However, there was no increase over control in obstructive hydrocephalus (obstructive: 8.65 ± 0.80 ng/ml).
  
  
  CONCLUSIONS
  AQP4 has a modulatory effect on ependyma stability and acts in CSF production and reabsorption. Therefore, the increase of AQP4 in the CSF in congenital hydrocephalus could be due to the fact that AQP4 passes from the parenchyma to the CSF and this AQP4 movement may be a consequence of ependyma denudation.
authors: Departamento de Anatomía, Facultad de Medicina, Universidad de La Laguna, La Laguna, Tenerife, Canary Island, Spain. acastane@ull.es.
authors: Leandro
authors: L
authors: Castañeyra-Ruiz
authors: Ibrahim
authors: I
authors: González-Marrero
authors: Juan M
authors: JM
authors: González-Toledo
authors: Agustin
authors: A
authors: Castañeyra-Ruiz
authors: Héctor
authors: H
authors: de Paz-Carmona
authors: Agustín
authors: A
authors: Castañeyra-Perdomo
authors: Emilia M
authors: EM
authors: Carmona-Calero
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