Serum Levels of Mature Brain-Derived Neurotrophic Factor (BDNF) and Its Precursor proBDNF in Healthy Subjects

Abstract

BACKGROUND: Accumulating evidence points to the brain-derived neurotrophic factor (BDNF) as a bio- marker for neuropsychiatric diseases, such as major depression. Mature BDNF is synthesized from its precursor form, proBDNF. Although BDNF levels in human blood can be measured using commercially available human BDNF ELISA kits, due to limited specificity of the BDNF antibody, these kits are unable to distinguish between proBDNF and mature BDNF. In this study, we measured serum levels of proBDNF and mature BDNF in healthy subjects, using human proBDNF and BDNF ELISA kits, respectively. METHODS: Serum levels of proBDNF and mature BDNF in healthy subjects (n = 40) were measured using the sand- wich human proBDNF and BDNF ELISA kits. RESULTS: In healthy subjects, serum levels of mature BDNF were 23.71 ± 5.61 ng/mL (mean ± S.D., n=40). Serum levels of proBDNF in healthy subjects were 7.58 ± 7.68 ng/mL (mean ± S.D., n=25). However in 15 subjects, serum lev- els of proBDNF were less than the minimum detectable concentration (0.5 ng/mL) of the kit. CONCLUSIONS: This study shows that serum levels of proBDNF and mature BDNF are measurable using either the commercially available human proBDNF or BDNF ELISA kits, although the sensitivity of proBDNF kit was unaccepta- bly low. These ELISA kits may be useful for measuring proBDNF and mature BDNF in the body fluids of patients with neuropsychiatric, cardiovascular and other diseases.