Selenium concentration in cerebrospinal fluid samples from a paediatric population.

Selenium is an important trace element for brain function. Our objective was to analyse cerebrospinal fluid (CSF) selenium (Se) in 89 paediatric patients. We also studied correlations between Se and other biochemical variables (age, CSF protein concentrations and glutathione peroxidase activity and plasma Se values). Cerebrospinal fluid Se values showed a significant negative correlation with the age of patients (r = -0.476; p < 0.0001), and positive with CSF total protein concentrations and GPX activity (r = 0.446, p < 0.001; r = 0.431; p = 0.001, respectively). No association was observed between plasma and CSF Se concentrations. Median CSF Se values were 32 times lower when compared with those for plasma. In conclusion, CSF Se concentrations depend on age and total CSF protein values. The association observed between CSF Se and GPX activity suggests that Se quantification might be a reflection of some Se-dependent protein function. Cerebrospinal fluid Se values were independent of serum Se concentrations.