Blood levels of brain derived neurotrophic factor in women with bipolar disorder and healthy control women

Abstract

Background Brain-derived neurotrophic factor (BDNF) protein has been implicated in the pathophysiology of mood disorders, with early data suggesting that blood levels may vary by severity of mood symptoms. BDNF polymorphism, val66met, has also been implicated in mood disorders. Methods Euthymic women with bipolar disorder (BD) (n=47) and healthy control women (n=26), ages 18–45, were clinically rated using the Montgomery-Asberg Depression Rating Scale (MADRS) and sampled for plasma BDNF concentration, with a subset undergoing genetic analysis for the val66met. Results BD and control groups did not differ on any demographic variables, nor in plasma BDNF levels or val66met polymorphism. Plasma BDNF concentration did not differ by val66met or BD subtype, nor was it correlated with age or illness duration. Within women with BD, lower plasma BDNF concentrations were significantly associated with higher MADRS scores, even after controlling for psychotropic medication use and illness duration. Limitations The sample was relatively small and exclusive to women, with further research needed to investigate the links between BDNF markers and mood symptom severity in both men and women. Conclusions The study provides a gender-specific investigation of plasma BDNF levels and mood, and the results add further evidence of a significant interplay between BDNF markers and psychiatric symptomatology. Further, this association did not appear to be confounded by use of psychotropic medication. Studies with larger samples of both genders are needed to further delineate this relationship.

Peripheral blood brain-derived neurotrophic factor in bipolar disorder: a comprehensive systematic review and meta-analysis

“…Blinding of laboratory staff to the clinical state of participants was reported in eight studies. 21,26,46,50,53,56,63,65 One study reported assigning samples randomly through enzyme-linked immunosorbent assay procedures. 26 Risk of bias and study quality within studies.…”

“…BDNF genotype was investigated in three of the included studies, with two finding no association between the Val66Met BDNF gene single-nucleotide polymorphism and BDNF levels, 40,50 and one study finding lower BDNF levels in bipolar disorder patients carrying the Met allele compared with Val homozygotes. 46 A recent meta-analysis, however, did not find any association between the BDNF Val66Met polymorphism and bipolar disorder.…”

Association between brain-derived neurotrophic factor genetic polymorphism Val66Met and susceptibility to bipolar disorder: a meta-analysis

“…Twenty-one case–control association studies met our criteria for the meta-analysis (Table 1 ). Data from four studies [ 26 - 29 ] were excluded due to the partial overlap with a larger sample size case–control study [ 30 ], and data from six studies were excluded due to less than 100 subjects in either patient group or control group [ 31 - 36 ]. Additionally, the case–control sample from a genome-wide association study was also excluded from current meta-analysis [ 37 ].…”

BDNF–TrkB signaling as a therapeutic target in neuropsychiatric disorders

“…174 A recent study comparing BDNF levels in first major depressive episode patients suffering either from bipolar or major depression found that while both groups showed significantly reduced plasma BDNF, those suffering bipolar disorder had even lower BDNF levels than did the major depression patients. 175 However, other studies found either no decrease in plasma BDNF in patients compared with controls 176 or even an increase in plasma BDNF compared with controls. 177 One study found that improvement in symptoms resulting from quetiapine treatment was accompanied by increases in BDNF in patients with depressive episodes and decreases in BDNF in patients with manic or mixed episodes, 178 suggesting differential BDNF alteration according to polarity of disease, adding a layer of complexity in analyzing the role of BDNF.…”