Novel test may predict risk for mood disorders by assessing brain protein

Researchers have developed a novel test to predict mood disorders based on levels of a protein found in the brain, according to study results published in Journal of Psychiatric Research.

“Although the associations between low serum mature brain-derived neurotrophic factor (mBDNF) levels and depression have been shown previously, many studies have used commercially available mBDNF Enzyme-Linked Immunosorbent Assay (ELISA) kits that are not very specific and may cross react with the precursor of BDNF (proBDNF),” Liying Lin, a PhD student at the University of South Australia, told Healio Psychiatry. “Importantly, these two proteins have opposite functions, with mBDNF promoting nerve cell survival while proBDNF promotes nerve cell death. Therefore, it is critical to measure their levels separately.”

Lin and colleagues sought to assess the change of mBDNF and proBDNF levels in the peripheral blood, and they used a specific ELISA to investigate their diagnostic value in the mood disorders. 

Results showed significantly decreased serum mBDNF levels among 90 individuals with MDD and 15 with bipolar disorder; however, there was no significant change among 14 individuals who were suicidal vs. a control group of 96 individuals. Among MDD subgroups, the serum mBDNF level for patients with MDD who had severe symptoms was significantly lower than those with moderate symptoms. Antidepressant-free patients had significantly lower serum mBDNF levels vs. antidepressant-treated patients.

For MDD and bipolar disorder, serum mBDNF yielded good diagnostic effectiveness, with sensitivity and specificity around 80% to 83%. In lymphocytes of MDD patients, levels of mBDNF, proBDNF and its receptor sortilin were upregulated compared with control subjects. The researchers noted confirmation of the reduction of serum mBDNF level in MDD and bipolar disorder according to specific ELISA assays for mBDNF.

“The etiology and mechanisms underlying depression are not well understood,” Lin said. “Furthermore, about 30% of patients with MDD do not respond to current treatments. Blood mBDNF and proBDNF may serve as objective biological markers of major depression and bipolar disorder and may assist clinicians in assessment of patients and developing a personalized treatment plan.”