Serum levels of brain-derived neurotrophic factor (BDNF), proBDNF and plasma 3-methoxy-4-hydroxyphenylglycol levels in chronic schizophrenia

BACKGROUND: We investigated the serum levels of brain-derived neurotrophic factor (BDNF), proBDNF and plasma 3-methoxy-4-hydroxyphenylglycol (MHPG) levels in patients with chronic schizophrenia. METHODS: Sixty-eight patients who met the DSM-IV-TR criteria and had a chronic schizophrenia (CS) duration of ≥ 5 years were enrolled. Their serum brain-derived BDNF and proBDNF levels were measured by enzyme-linked immunosorbent assays, and their plasma MHPG levels were analyzed by high-performance liquid chromatography with electrochemical detection. RESULTS: The plasma MHPG levels were significantly lower in the CS group (3.9 ± 1.8 ng/ml) compared to those in the group of 32 age- and sex-matched healthy controls (5.1 ± 2.4 ng/ml). The serum BDNF levels were significantly lower in the CS group (8.9 ± 4.8 ng/ml) compared to the control group (12.2.1 ± 6.8 ng/ml). No correlation was observed between plasma MHPG and BDNF in the CS group. CONCLUSION: These results suggest that hypo-activity of noradrenergic neurons and decreased BDNF secretion exist in chronic schizophrenic patients.