The BDNF Val66Met polymorphism and plasma brain-derived neurotrophic factor levels in Han Chinese patients with bipolar disorder and schizophrenia.
OBJECTIVE
Brain-derived neurotropic factor (BDNF) is widely distributed in the peripheral and central nervous systems. BDNF and its gene polymorphism may be important in synaptic plasticity and neuron survival, and may become a key target in the physiopathology of several mental illnesses. To elucidate the role of BDNF, we compared the plasma BDNF levels and the BDNF Val66Met gene variants effect in several mental disorders.


METHODS
We enrolled 644 participants: 177 patients with bipolar I disorder (BP-I), 190 with bipolar II disorder (BP-II), 151 with schizophrenia, and 126 healthy controls. Their plasma BDNF levels and BDNF Val66Met single nucleotide polymorphisms (SNP) were checked before pharmacological treatment.


RESULTS
Plasma levels of BDNF were significantly lower in patients with schizophrenia than in healthy controls and patients with bipolar disorder (F = 37.667, p<0.001); the distribution of the BDNF Val66Met SNP was not different between groups (χ(2) = 5.289, p = 0.507). Nor were plasma BDNF levels significantly different between Met/Met, Met/Val, and Val/Val carriers in each group, which indicated that the BDNF Val66Met SNP did not influence plasma BDNF levels in our participants. Plasma BDNF levels were, however, significantly negatively correlated with depression scores in patients with bipolar disorder and with negative symptoms in patients with schizophrenia.


CONCLUSIONS
We conclude that plasma BDNF profiles in different mental disorders are not affected by BDNF Val66Met gene variants, but by the process and progression of the illness itself.
Department of Neurology, School of Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan; Department of Psychiatry, National Cheng Kung University, Taiwan. Electronic address: shioulan@mail.ncku.edu.tw.
Shiou-Lan
SL
Chen
Department of Psychiatry, National Cheng Kung University, Taiwan; National Cheng Kung University Hospital, Taiwan; Addiction Research Center, National Cheng Kung University, Taiwan.
Sheng-Yu
SY
Lee
Department of Psychiatry, National Cheng Kung University, Taiwan; Institute of Allied Health Sciences, College of Medicine, National Cheng Kung University, Taiwan.
Yun-Hsuan
YH
Chang
Department of Psychiatry, National Cheng Kung University, Taiwan; Neuropharmacology Section, Laboratory of Pharmacology and Chemistry, National Institute of Environmental Health Sciences/National Institutes of Health, Research Triangle Park, NC, USA.
Shih-Heng
SH
Chen
Department of Psychiatry, National Cheng Kung University, Taiwan; Neuropharmacology Section, Laboratory of Pharmacology and Chemistry, National Institute of Environmental Health Sciences/National Institutes of Health, Research Triangle Park, NC, USA.
Chun-Hsien
CH
Chu
Department of Psychiatry, National Cheng Kung University, Taiwan; National Cheng Kung University Hospital, Taiwan.
Tzu-Yun
TY
Wang
Department of Psychiatry, National Cheng Kung University, Taiwan; National Cheng Kung University Hospital, Taiwan; Addiction Research Center, National Cheng Kung University, Taiwan.
Po-See
PS
Chen
Department of Psychiatry, National Cheng Kung University, Taiwan; National Cheng Kung University Hospital, Taiwan; Addiction Research Center, National Cheng Kung University, Taiwan.
I-Hui
IH
Lee
Department of Psychiatry, National Cheng Kung University, Taiwan; National Cheng Kung University Hospital, Taiwan; Addiction Research Center, National Cheng Kung University, Taiwan.
Yen-Kuang
YK
Yang
Neuropharmacology Section, Laboratory of Pharmacology and Chemistry, National Institute of Environmental Health Sciences/National Institutes of Health, Research Triangle Park, NC, USA.
Jau-Shyong
JS
Hong
Department of Psychiatry, National Cheng Kung University, Taiwan; National Cheng Kung University Hospital, Taiwan; Institute of Allied Health Sciences, College of Medicine, National Cheng Kung University, Taiwan; Addiction Research Center, National Cheng Kung University, Taiwan; Institute of Behavior Medicine, National Cheng Kung University, Taiwan; Center for Neuropsychiatric Research, National Health Research Institutes, Taiwan. Electronic address: rblu@mail.ncku.edu.tw.
Ru-Band
RB
Lu
D000328:Adult; D000704:Analysis of Variance; D044466:Asian People / Q000208:ethnology / Q000235:genetics; D001714:Bipolar Disorder / Q000097:blood / Q000208:ethnology / Q000235:genetics*; D019208:Brain-Derived Neurotrophic Factor / Q000097:blood* / Q000235:genetics*; D005260:Female; D005787:Gene Frequency; D020022:Genetic Predisposition to Disease / Q000235:genetics*; D005838:Genotype; D006801:Humans; D008297:Male; D008715:Methionine / Q000235:genetics; D008875:Middle Aged; D020641:Polymorphism, Single Nucleotide / Q000235:genetics*; D012559:Schizophrenia / Q000097:blood / Q000208:ethnology / Q000235:genetics*; D014633:Valine / Q000235:genetics; D055815:Young Adult
D019208:Brain-Derived Neurotrophic Factor; C579455:BDNF protein, human; D008715:Methionine; D014633:Valine
BDNF Val66Met gene; Bipolar disorders; Plasma BDNF; Schizophrenia