Brain-derived neurotrophic factor, impaired glucose metabolism, and bipolar disorder course

• Published in: Bipolar disorders Vol. 18; no. 4; pp. 373 - 378
• Main Authors: Mansur, Rodrigo B, Santos, Camila M, Rizzo, Lucas B, Asevedo, Elson, Cunha, Graccielle R, Noto, Mariane N, Pedrini, Mariana, Zeni-Graiff, Maiara, Cordeiro, Quirino, Vinberg, Maj, Kapczinski, Flavio, McIntyre, Roger S, Brietzke, Elisa
• Format: Journal Article
• Language: English
• Published: Denmark Blackwell Publishing Ltd 01-06-2016
• Subjects: Adult; Alcohol Drinking - epidemiology; Biomarkers - blood; bipolar disorder; Bipolar Disorder - blood; Bipolar Disorder - diagnosis; Bipolar Disorder - drug therapy; Bipolar Disorder - physiopathology; brain-derived neurotrophic factor; Brain-Derived Neurotrophic Factor - blood; Brazil; diabetes; Diabetes Mellitus, Type 2 - metabolism; Diabetes Mellitus, Type 2 - psychology; Diagnostic and Statistical Manual of Mental Disorders; Disease Progression; Female; Glucose - metabolism; Humans; impaired glucose metabolism; Male; Middle Aged; Prediabetic State - metabolism; Prediabetic State - psychology; Risk Factors; Smoking - epidemiology; Statistics as Topic; bipolar disorder; brain-derived neurotrophic factor; diabetes; impaired glucose metabolism
• ISSN: 1398-5647; 1399-5618
• DOI: 10.1111/bdi.12399

Objectives
The neurotrophin brain‐derived neurotrophic factor (BDNF) has been proposed as a potential biomarker in bipolar disorder (BD). However, current evidence is limited and results have been highly heterogeneous. This study aimed to assess the moderating effect of impaired glucose metabolism (IGM) on plasma levels of BDNF in individuals with BD, and on the relationship between BDNF and variables of illness course.
Methods
We measured and compared the plasma levels of BDNF in individuals with BD (n=57) and healthy controls (n=26). IGM was operationalized as pre‐diabetes or type 2 diabetes mellitus. Information related to current and past psychiatric/medical history, as well as prescription of pharmacological treatments was also captured.
Results
Individuals with BD had lower levels of BDNF, relative to healthy controls, after adjustment for age, gender, current medications, smoking, alcohol use, and IGM (P=.046). There was no effect of IGM (P=.860) and no interaction between BD diagnosis and IGM (P=.893). Peripheral BDNF levels were positively correlated with lifetime depressive episodes (P<.001), psychiatric hospitalizations (P=.001) and suicide attempts (P=.021). IGM moderated the association between BDNF and the number of previous mood episodes (P<.001), wherein there was a positive correlation in euglycemic participants and a negative correlation in individuals with IGM.
Conclusions
BD is independently associated with lower levels of BDNF; IGM may modify the relationship between BDNF and BD course, suggesting an interactive effect of BDNF with metabolic status on illness progression.