Stability analysis of vascular endothelial growth factor in cerebrospinal fluid.

Vascular endothelial growth factor (VEGF) is a promising biological marker and prognostic indicator in many neurological diseases. Although VEGF concentrations in plasma and cerebrospinal fluid (CSF) are increasingly reported, CSF-VEGF stability pre- and during-assay procedures is seldom evaluated. In the current study, we investigated VEGF variability and stability in CSF related to sample preparation, storage, and routine experimental procedures. Results showed that contaminant cell breakdown or aggregation can occur gradually before sample processing. However, after the removal of contaminant cell components, CSF-VEGF levels did not show significant changes in samples incubated at room temperature for 5 h, thawed/refrozen for 6 cycles. Samples preserved at -80 °C for up to 7 years continued to show measurable levels. Since some cellular components such as platelets contain a large amount of releasable VEGF, we conclude that CSF samples should be processed as soon as possible to carefully remove all cellular components and prevent possible consequent release of VEGF into CSF. After centrifugation to remove cellular contents, VEGF in CSF was relatively stable during routine experimental procedures and storage.