Brain-derived neurotrophic factor (BDNF) Val66Met polymorphism in schizophrenia is associated with age at onset and symptoms.
ABSTRACT Brain-derived neurotrophic factor (BDNF) is a neurotrophic factor that promotes several functions of neurons and modulates neurotransmissions. It has been reported that there are alterations of BDNF levels in schizophrenic brains and that BDNF gene expressional changes would be responsible for the etiology of schizophrenia. Recent studies have shown that a variation of BDNF gene (Val66Met polymorphism) affects the function of neurons, and is associated with several neurological and psychiatrical disorders. We investigated the relationship between BDNF Val66Met polymorphism and the onset age as well as levels of clinical symptoms in 159 of chronic schizophrenia in-patients diagnosed by DSM-IV. The mean onset ages were 27.5+/-9.5 for BDNF Val/Val, 25.5+/-7.4 for BDNF Val/Met and 22.9+/-6.0 for BDNF Met/Met and this polymorphism was significantly associated with age at onset (P=0.023). The mean Brief Psychiatric Rating Scale scores (BPRS) were significantly different among those three groups (P=0.003). No significant differences were demonstrated comparing the BDNF genotype distributions of positive and negative family history (P=0.21). Our investigation indicates that the BDNF gene Val66Met polymorphism is related to the onset age of schizophrenia and the levels of clinical symptoms that remain after long-term antipsychotic treatment.
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ABSTRACT: Brain-derived neurotrophic factor (BDNF) has been implicated in the pathophysiology of schizophrenia, yet its role in the development of specific symptoms is unclear. Methamphetamine (METH) users have an increased risk of psychosis and schizophrenia, and METH-treated animals have been used extensively as a model to study the positive symptoms of schizophrenia. We investigated whether METH treatment in BDNF heterozygous (HET) mutant mice has cumulative effects on sensorimotor gating, including the disruptive effects of psychotropic drugs. BDNF HETs and wildtype (WT) littermates were treated during young adulthood with METH and, following a 2-week break, prepulse inhibition (PPI) was examined. At baseline, BDNF HETs showed reduced PPI compared to WT mice irrespective of METH pre-treatment. An acute challenge with amphetamine (AMPH) disrupted PPI but male BDNF HETs were more sensitive to this effect, irrespective of METH pre-treatment. In contrast, female mice treated with METH were less sensitive to the disruptive effects of AMPH, and there were no effects of BDNF genotype. Similar changes were not observed in the response to an acute apomorphine (APO) or MK-801 challenge. These results show that genetically-induced reduction of BDNF caused changes in a behavioral endophenotype relevant to the positive symptoms of schizophrenia. However, major sex differences were observed in the effects of a psychotropic drug challenge on this behavior. These findings suggest sex differences in the effects of BDNF depletion and METH treatment on the monoamine signaling pathways that regulate PPI. Given that these same pathways are thought to contribute to the expression of positive symptoms in schizophrenia, this work suggests that there may be significant sex differences in the pathophysiology underlying these symptoms. Elucidating these sex differences may be important for our understanding of the neurobiology of schizophrenia and developing better treatments strategies for the disorder.Frontiers in Cellular Neuroscience 06/2013; 7:92. DOI:10.3389/fncel.2013.00092 · 4.18 Impact Factor
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ABSTRACT: Cannabis use may be considered as an additional risk factor in a diathesis-stress model of schizophrenia where the risk of developing the illness would be higher in genetic vulnerable people. In this regard, much of the research on cannabis and psychosis is currently focusing on gene-environment interactions. The present review will focus on the interaction between genes and cannabis exposure in the development of psychotic symptoms and schizophrenia and the biological mechanisms of cannabis. Cannabis use has been shown to act together with other environmental factors such as childhood trauma or urbanicity producing synergistic dopamine sensitization effects. Studies on gene-environment interaction have mainly included genetic variants involved in the regulation of the dopaminergic system. The most promising genetic variants in this field are COMT, CNR1, BDNF, AKT1 and NRG1. Additionally, the interaction with other environmental factors and possible gene-gene interactions are considered in the etiological model.Current pharmaceutical design 06/2012; 18(32):5024-35. DOI:10.2174/138161212802884609 · 3.29 Impact Factor
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ABSTRACT: Auditory P50 sensory gating deficits correlate with genetic risk for schizophrenia and constitute a plausible endophenotype for the disease. The well-supported role of catechol-O-methyltransferase (COMT), brain-derived neurotrophic factor (BDNF) and neuregulin 1 (NRG1) genes in neurodevelopment and cognition make a strong theoretical case for their influence on the P50 endophenotype. The possible role of NRG1, COMT Val158Met and BDNF Val66Met gene polymorphisms on the P50 endophenotype was examined in a large sample consisting of psychotic patients, their unaffected relatives and unrelated healthy controls using linear regression analyses. Although P50 deficits were present in patients and their unaffected relatives, there was no evidence for an association between NRG1, COMT Val158Met or BDNF Val66Met genotypes and the P50 endophenotype. The evidence from our large study suggests that any such association between P50 indices and NRG1, COMT Val158Met or BDNF Val66Met genotypes, if present, must be very subtle.Psychological Medicine 02/2011; 41(2):263-76. DOI:10.1017/S003329170999239X · 5.43 Impact Factor