Brain-derived neurotrophic factor and neuron-specific enolase, but not S100 β, levels are associated to the occurrence of delirium in intensive care unit patients

Abstract

Purpose The aim of this study was to determine the association between serum concentrations of brain-derived neurotrophic factor (BDNF), neuron-specific enolase (NSE), and S100 β and the occurrence of delirium in critically ill patients. Material and Methods This case-control study included 30 patients with delirium and 30 matched controls in a 16-bed general intensive care unit (ICU). Serum BDNF, NSE, and S100 concentrations were determined by enzyme-linked immunosorbent assay assays at the time of ICU admission and on the day before delirium was diagnosed. Delirium was diagnosed by confusion assessment method for the ICU. Results At ICU admission, serum BDNF levels were significantly higher in delirious patients than in nondelirious controls (2.89 ± 1.48 vs 1.79 ± 0.89 ng/mL, respectively). When we compared serum S100 levels, there were no significant differences between the groups. Neuron-specific enolase values were significantly higher in the delirious patients than in the nondelirious controls (0.79 ± 0.03 ng/mL vs 0.59 ± 0.01 ng/mL, respectively). When patients who earlier developed delirium were separately analyzed, it was determined that serum NSE and BDNF levels at admission were significant higher only in this group. Conclusions Our results suggest that admission serum BDNF and NSE levels are associated with the occurrence of delirium in ICU patients.