Serum and plasma BDNF levels in major depression: a replication study and meta-analyses

Area of Science:

• Neuroscience
• Psychiatry
• Biochemistry

Background:

• Major depression (MD) is associated with altered brain-derived neurotrophic factor (BDNF) signaling.
• Previous studies indicate decreased serum and plasma BDNF levels in MD patients.

Purpose of the Study:

• To replicate findings on BDNF levels in MD patients.
• To conduct meta-analyses on serum and plasma BDNF levels in MD.
• To investigate the influence of gender on BDNF levels in MD.

Main Methods:

• Replication study analyzing serum BDNF levels.
• Two meta-analyses: one on serum BDNF (489 patients/483 controls) and one on plasma BDNF (161 patients/211 controls).
• Subgroup analyses for gender differences.

Main Results:

• Replication study showed decreased serum BDNF and down-regulation of mature BDNF (mBDNF) in MD patients.
• Meta-analyses confirmed reduced serum BDNF (P<0.0001) and plasma BDNF (P=0.02) in MD.
• No significant gender difference in serum BDNF effect size (P=0.18).

Conclusions:

• Peripheral BDNF alterations are evident in major depression.
• Results support further research into BDNF as a biomarker for MD diagnosis and personalized therapy.