Plasma BDNF Level in Major Depression: Biomarker of the Val66Met BDNF Polymorphism and of the Clinical Course in Met Carrier Patients

Plasma and Platelet Brain-Derived Neurotrophic Factor (BDNF) Levels in Bipolar Disorder Patients with Post-Traumatic Stress Disorder (PTSD) or in a Major Depressive Episode Compared to Healthy Controls

Post-traumatic stress disorder (PTSD) is a highly disabling mental disorder arising after traumatism exposure, often revealing critical and complex courses when comorbidity with bipolar disorder (BD) occurs. To search for PTSD or depression biomarkers that would help clinicians define BD presentations, this study aimed at preliminarily evaluating circulating brain-derived-neurotrophic factor (BDNF) levels in BD subjects with PTSD or experiencing a major depressive episode versus controls. Two bloodstream BDNF components were specifically investigated, the storage (intraplatelet) and the released (plasma) ones, both as adaptogenic/repair signals during neuroendocrine stress response dynamics. Bipolar patients with PTSD (n = 20) or in a major depressive episode (n = 20) were rigorously recruited together with unrelated healthy controls (n = 24) and subsequently examined by psychiatric questionnaires and blood samplings. Platelet-poor plasma (PPP) and intraplatelet (PLT) BDNF were measured by ELISA assays. The results showed markedly higher intraplatelet vs. plasma BDNF, confirming platelets' role in neurotrophin transport/storage. No between-group PPP-BDNF difference was reported, whereas PLT-BDNF was significantly reduced in depressed BD patients. PLT-BDNF negatively correlated with mood scores but not with PTSD items like PPP-BDNF, which instead displayed opposite correlation trends with depression and manic severity. Present findings highlight PLT-BDNF as more reliable at detecting depression than PTSD in BD, encouraging further study into BDNF variability contextually with immune-inflammatory parameters in wider cohorts of differentially symptomatic bipolar patients.

[The relationship between the rs6265 polymorphism of the BDNF gene and the level of serum neurotrophic factor in patients with Parkinson's disease]

OBJECTIVE

To evaluate the clinical features and the level of serum brain-derived neurotrophic factor (BDNF) in groups of patients with Parkinson's disease (PD) differentiated by the genotypes of BDNF polymorphism (rs6265).

MATERIAL AND METHODS

The level of serum BDNF in the biomarkers' multiplex panel of neurodegenerative diseases (HNDG3MAG-36K) was assessed in 134 PD patients. Allele discrimination was carried out by real-time PCR using TaqMan probes for the analysis of BDNF rs6265 polymorphism in groups of patients and controls (n=192) matched for sex, age and ethnicity.

RESULTS

Comparing the distribution of rs6265 genotypes and alleles between groups of patients and controls no significant differences were found (p>0.05). Serum BDNF levels varied significantly by genotype (rs6265) among PD patients. Minimum mean serum BDNF level (320.1±164.6 pg/ml) was noted for individuals with the AA genotype, which significantly differs from the corresponding indicator among individuals with GA (2944.2±1590.6 pg/ml; p=0.0001) and GG genotypes (2949.4±1620.6 pg/ml; p=3.9×10-5). The concentration of BDNF significantly differed between patients with different forms of PD (p=0.0007) and increased as the stage of the disease progressed according to Hoehn and Yahr staging scale (p=1.0×10-6).

CONCLUSION

The BDNF rs6265 polymorphism was not associated with the development of PD in the studied population. The variability of the mean serum BDNF level was established depending on the genotype of the BDNF polymorphism in PD patients and a number of clinical features.

Variation of Circulating Brain-Derived Neurotrophic Factor (BDNF) in Depression: Relationships with Inflammatory Indices, Metabolic Status and Patients' Clinical Features

This study seeks to offer a contribution to the method of subtyping major depressed patients by exploring the possible relationships between circulating brain-derived neurotrophic factor (BDNF), different peripheral inflammatory/metabolic markers in the blood and clinical characteristics. Thirty-nine patients, thoroughly diagnosed according to the DSM-5 criteria, underwent a comprehensive set of evaluations encompassing structured interviews, rating scales and a panel of blood tests. Correlation and comparison analyses were carried out by means of non-parametric statistical tests. Concurrently, a principal component analysis was performed to explain biochemical variance. The findings of our research unveiled that leukocyte counts, their ratios and other inflammatory parameters are positively correlated with depression scores. Moreover, we found variations within the BDNF pools of depressed patients. Specifically, higher levels of platelet-poor plasma BDNF (PPP-BDNF) were correlated with augmented inflammatory markers in patients showing specific episode characteristics, whereas reduced platelet BDNF (PLT-BDNF) provided a better indication of the changes that were linked to a diagnosis of long-term depression. Our findings suggest that PPP-BDNF and PLT-BDNF might differentiate depression conditions. They also imply usefulness in appraising peripheral biomarker profiles in patients for a deeper characterization of major depressive episodes. At the same time, it is plausible that they might constitute novel avenues for developing more tailored therapeutic strategies for patients with MDs.

BDNF-related mutations in major depressive disorder: a systematic review

OBJECTIVE

A better understanding of the genetic, molecular and cellular mechanisms of brain-derived neurotrophic factor (BDNF) and its association with neuroplasticity could play a pivotal role in finding future therapeutic targets for novel drugs in major depressive disorder (MDD). Because there are conflicting results regarding the exact role of BDNF polymorphisms in MDD still, we set out to systematically review the current evidence regarding BDNF-related mutations in MDD.

METHODS

We conducted a keyword-guided search of the PubMed and Embase databases, using 'BDNF' or 'brain-derived neurotrophic factor' and 'major depressive disorder' and 'single-nucleotide polymorphism'. We included all publications in line with our exclusion and inclusion criteria that focused on BDNF-related mutations in the context of MDD.

RESULTS

Our search yielded 427 records in total. After screening and application of our eligibility criteria, 71 studies were included in final analysis. According to present overall scientific data, there is a possibly major pathophysiological role for BDNF neurotrophic systems to play in MDD. However, on the one hand, the synthesis of evidence makes clear that likely no overall association of BDNF-related mutations with MDD exists. On the other hand, it can be appreciated that solidifying evidence emerged on specific significant sub-conditions and stratifications based on various demographic, clinico-phenotypical and neuromorphological variables.

CONCLUSIONS

Further research should elucidate specific BDNF-MDD associations based on demographic, clinico-phenotypical and neuromorphological variables. Furthermore, biomarker approaches, specifically combinatory ones, involving BDNF should be further investigated.

The Relationship Among BDNF Val66Met Polymorphism, Plasma BDNF Level, and Trait Anxiety in Chinese Patients With Panic Disorder

BACKGROUND

Brain-derived neurotrophic factor (BDNF) is a candidate for susceptibility locus of Panic disorder (PD). However, the findings about the role of the BDNF Val66Met variant in PD were not consistent. Till now, the relationship between BDNF Val66Met polymorphism and anxiety-related traits in PD patients has been rarely explored. This study aimed to explore the relationship among BDNF Val66Met polymorphism, plasma BDNF level and anxiety-related trait in Chinese PD patients.

METHOD

This multi-center study included 116 PD patients and 99 health controls. We detected single-nucleotide polymorphism (SNP) of BDNF rs6265 (Val66Met) and BDNF plasma level in the two groups. In addition, PD patients were administered the State-Trait Anxiety Inventory (STAI), Panic Disorder Severity Scale-Chinese Version (PDSS-CV) and Hamilton Anxiety Rating Scale (HAMA-14). Quantitative comparison of the differences of BDNF concentration among subjects with different genotypes and association between BDNF Val66Met genotype and trait anxiety were performed.

RESULTS

There were no significant differences in the genotype frequency (p = 0.79) or allele frequency (p = 0.88) between PD patients and health controls. BDNF plasma levels of PD patients were significantly lower than those in control group (p = 0.003). BDNF plasma levels of the Met/Met genotype were significantly lower than those of Val/Met genotype in PD patients (p = 0.033). PD patients carried Met/Met genotype showed significantly higher scores in STAI trait compared to those carried Val/Val genotype (p = 0.045) and Val/Met genotype (p = 0.018). STAI trait scores of PD patients with agoraphobia were significantly higher than those of patients without agoraphobia (p < 0.05). The ANCOVA showed that the dependent variable STAI trait score was significantly affected by factor "genotype" (Val/Val, Val/Met, Met/Met, p = 0.029), and covariate "agoraphobia" (p = 0.008). In this model, 11.5% of the variance of the STAI trait score was explained by the BDNF genotype. Contrast analysis showed STAI trait scores of Met/Met subjects were significantly higher than those of Val/Met (p = 0.018) and Val/Val individuals (p = 0.045).

CONCLUSION

We found that anxiety trait was associated with the BDNF polymorphism in PD patients. BDNF Met/Met genotype may decrease plasma BDNF level and increase trait anxiety in panic disorder.

Hippocampal miR-206-3p participates in the pathogenesis of depression via regulating the expression of BDNF

As a widely-known neuropsychiatric disorder, the exact pathogenesis of depression remains elusive. MiRNA-206 (miR-206) is conventionally known as one of the myomiRs and has two forms: miR-206-3p and miR-206-5p. Recently, miR-206 has been demonstrated to regulate the biosynthesis of brain-derived neurotrophic factor (BDNF), a very popular target involved in depression and antidepressant responses. Here we assumed that miR-206 may play a role in depression, and various methods including the chronic social defeat stress (CSDS) model of depression, quantitative real-time reverse transcription PCR, western blotting, immuofluorescence and virus-mediated gene transfer were used together. It was found that CSDS robustly increased the level of miR-206-3p but not miR-206-5p in the hippocampus. Both genetic overexpression of hippocampal miR-206-3p and intranasal administration of AgomiR-206-3p induced not only notable depressive-like behaviors but also significantly decreased hippocampal BDNF signaling cascade and neurogenesis in naïve C57BL/6J mice. In contrast, both genetic knockdown of hippocampal miR-206-3p and intranasal administration of AntagomiR-206-3p produced significant antidepressant-like effects in the CSDS model of depression. Furthermore, it was found that the antidepressant-like effects induced by miR-206-3p inhibition require the hippocampal BDNF-TrkB system. Taken together, hippocampal miR-206-3p participates in the pathogenesis of depression by regulating BDNF biosynthesis and is a feasible antidepressant target.

Effect of vortioxetine vs. escitalopram on plasma BDNF and platelet serotonin in depressed patients

Escitalopram and vortioxetine are efficacious antidepressants. They directly target serotonin (5-HT) system, but vortioxetine mechanism of action is distinct from the one of selective serotonin reuptake inhibitors (SSRIs). Treatment with SSRIs decrease platelet 5-HT concentration and increase peripheral brain-derived neurotrophic factor (BDNF) levels. Since vortioxetine has a multimodal mechanism of action, it is expected to have a greater effect on circulatory BDNF concentration, compared to conventional antidepressants. This longitudinal study aimed to explore and compare the effects of 4-weeks of treatment with vortioxetine and escitalopram on plasma BDNF and platelet 5-HT concentration in patients with major depressive disorder (MDD). The results revealed that vortioxetine significantly increased plasma BDNF concentration (p = .018) and significantly decreased platelet 5-HT concentration (p < .001). Treatment with escitalopram significantly decreased platelet 5-HT concentration (p < .001), but it did not affect plasma BDNF concentration (p = .379). Response to vortioxetine was not predicted by baseline plasma BDNF or platelet 5-HT concentration, but response to escitalopram was predicted by baseline platelet 5-HT concentration. These effects might be due to vortioxetine unique mechanism of action, but the clinical implications are unclear. It remains to be determined whether this finding extends during long-term vortioxetine treatment, and which, if any, clinical effects emerge from BDNF increase.

Associations between brain-derived neurotrophic factor and cognitive impairment in panic disorder

INTRODUCTION

Our study was designed to examine the relationship between Brain-Derived Neurotrophic Factor (BDNF) genotypes (rs6265, Val66Met), BDNF plasma levels, and cognitive impairment in Chinese patients with panic disorder (PD).

METHODS

Total 85 patients with PD and 91 healthy controls finally completed all assessments. The severity of panic symptoms and whole anxiety of PD was measured by Panic Disorder Severity Scale-Chinese Version (PDSS-CV) and Hamilton Anxiety Scale (HAMA-14). Montreal Cognitive Assessment (MoCA) and some neurocognitive measures were conducted to evaluate the cognitive performance. All participants were detected for the plasma BDNF levels and BDNF Val66Met polymorphism before assessment and treatment.

RESULTS

No significant differences were found in the BDNF allele frequencies and the BDNF genotype distributions between healthy controls and PD patients. BDNF Met/Met genotype was associated with lower BDNF plasma levels in PD patients, and PD patients with BDNF Met/Met genotype had the lower scores in the attention and speed of processing domains compared to those with Val/Val and Met/Val genotype (p's < .05). Among PD patients, the BDNF plasma levels showed moderate positive correlations with Stroop interference (r = .60, p < .001). Using the MoCA data, the BDNF plasma levels were correlated with delayed memory (r = .50, p < .001), verbal learning (r = .45, p < .001), and total scores of MoCA (r = .51, p < .001).

CONCLUSIONS

The BDNF Met/Met genotype may be associated with lower BDNF plasma levels and cognitive impairments in PD patients.

Genetic Variation Associated With Depressive Symptoms in Breast Cancer Patients: A Systematic Review

BACKGROUND

Depressive symptoms are highly prevalent in breast cancer patients. These symptoms can contribute to lower treatment adherence, increased healthcare charges, and higher mortality rates. Growing evidence suggests that genetic variations may be associated with depressive symptom susceptibility.

OBJECTIVE

To comprehensively review current findings on the association of genetic variations with depressive symptoms in breast cancer patients.

METHODS

A literature search was conducted using keywords such as gene variation, single-nucleotide polymorphism, depression/depressive symptoms, and breast cancer. Four hundred articles were retrieved from PubMed, Web of Science, CINAHL, and PsycINFO, yielding 9 full-text, data-based articles. The study quality was assessed using the STrengthening the REporting of Genetic Association studies guideline.

RESULTS

Genetic polymorphisms in brain-derived neurotrophic factor (BDNF), interferon γ receptor 1 (IFNGR1), interleukin-6 (IL-6), tumor necrosis factor α (TNFA), and IL-1B were found to be associated with depressive symptoms among breast cancer patients. The role of serotonin transporter gene linked promotor region (5-HTTLPR) functional polymorphisms on depressive symptoms was inconclusive. The overall quality of reporting results and methods was medium.

CONCLUSIONS

This is the first review of genetic variations related to differences in levels of depressive symptoms among breast cancer patients. Genetic polymorphisms in inflammatory, neuronal system, and signal transduction pathways can influence the susceptibility. However, more research regarding this topic is needed to further clarify genetic risk factors.

IMPLICATIONS FOR PRACTICE

Healthcare providers may determine patients at higher risk of developing depression and symptom outcomes if genetic biomarkers with good sensitivity/specificity are provided. This knowledge can potentially help the development of personalized treatment and decision making for those patients.

Association between plasma dipeptidyl peptidase-4 activity to brain-derived neurotrophic factor ratio and depressive symptoms in middle-aged and older adults with normal glucose tolerance: A cross-sectional study

Objectives: Attenuation of brain-derived neurotrophic factor (BDNF) availability and increased dipeptidyl peptidase-4 (DPP4) activity have both been reported to link to the pathogenesis of depression. The aim of this study was to test the correlation between depressive symptoms and plasma DPP4 activity to BDNF ratio (DBR).Methods: We evaluated DPP4 activity, BDNF, oxidative stress parameters and inflammatory markers and calculated DBR in a cross-sectional sample of 1640 non-diabetic participants.Results: DPP4 activity was negatively related to BDNF in participants with and without depressive symptoms (r= -0.351 and r= -0.404, p<.001). Nitrotyrosine and 8-iso-PGF2a mediated 18.4 and 12.6% of the total effect of DPP4 activity on BDNF, respectively. 8-iso-PGF2a, nitrotyrosine, C-reactive protein, interleukin-6 and PHQ-9 score progressively increased across DBR quartiles. Participants whose DBRs were in the highest quartile had 2.64-fold increased odds (OR = 3.03) of depressive symptoms. The depressive symptoms risk increased more with lower levels of BDNF and higher levels of DPP4 activity (p<.05).Conclusions: Our data suggested inverse correlation between DPP4 activity and BDNF through the oxidative stress mediator. The positive relationship between DBR and depressive symptoms risk raises feasibility of identifying DBR as a novel biological marker or even a possible therapeutic target for depression.

Assessing BDNF as a mediator of the effects of exercise on depression

Brain-derived neurotrophic factor (BDNF) is associated with neuronal growth and reduced BDNF has been implicated in depression. A recent meta-analysis documented reliable effects of exercise on BDNF levels (Szuhany et al., 2015); although, few studies included participants with mental health conditions. In this study, we examine whether increased exercise was associated with enhanced BDNF response in depressed patients, and whether this change mediated clinical benefits. A total of 29 depressed, sedentary participants were randomized to receive either behavioral activation (BA) plus an exercise or stretching prescription. Blood was collected prior to (resting BDNF levels) and following an exercise test (pre-to post-exercise BDNF change) at four points throughout the study. Participants also completed depression and exercise assessments. BDNF increased significantly across all assessment points (p < 0.001, d = 0.83). Changes in BDNF from pre-to post-exercise were at a moderate effect for the interaction of exercise and time which did not reach significance (p = 0.13, d = 0.53), with a similar moderate, non-significant effect for resting BDNF levels (p = 0.20, d = 0.49). Contrary to hypotheses, change in resting BDNF or endpoint change in BDNF was not associated with changes in depression. In an intervention that included active treatment (BA), we could not verify an independent predictive effect for changes in BDNF across the trial. Overall, this study adds to the literature showing reliable effects of acute exercise on increasing BDNF and extends this research to the infrequently studied depressed population, but does not clarify the mechanism behind exercise benefits for depression. CLINICAL TRIALS REGISTRY (CLINICALTRIALS.GOV): NCT02176408, "Efficacy of Adjunctive Exercise for the Behavioral Treatment of Major Depression".

SOD2 genetic polymorphism (rs4880) has no impact on 6-month response to antidepressant treatment and inflammatory biomarkers in depressed patients

Two thirds of patients suffering from a major depressive episode (MDE) do not reach a complete response with antidepressant drugs. This lack of response is due to several factors, including genetic determinants. Since major depressive disorder is associated with inflammatory and oxidative stress abnormalities, the metabolism of superoxide anions might be involved in non-response to antidepressant drugs. Superoxide anions are metabolized by manganese-dependent superoxide dismutase (SOD2) in the mitochondria. A functional genetic polymorphism (SOD2, rs4880), responsible of a 40% reduction in enzyme activity, is associated with anti-inflammatory response of rosuvastatin. We investigated the association of ala-allele of SOD2 rs4880 and both antidepressant efficacy and inflammatory parameters in patients treated for a MDE with antidepressant drugs. The Hamilton Depression Rating Scale (HDRS) score and levels of plasma CRP and inflammatory cytokines were assessed at baseline, one month (M1), 3 months (M3) and 6 months (M6) after antidepressant treatment. They were compared according to SOD2 genetic polymorphism. Of the 484 patients studied, 361 (74.6%) carried the ala-allele (Ala group), 123 (25.4%) of them had Val/Val genotype (Val/Val group). No significant difference was observed between the Ala and Val/Val groups neither for baseline clinical characteristics, nor for HDRS scores, response/remission rates, plasma CRP and cytokine levels throughout the study. The rs4880 SOD2 genetic polymorphism was not associated with the clinical response and cytokines levels after antidepressant treatment. These data suggest that SOD2 is not a major genetic determinant of antidepressant response. Other genes of the oxidative stress pathways should be explored in further studies.

Mechanisms of Panax ginseng action as an antidepressant

OBJECTIVES

Panax ginseng, a well-known traditional Chinese medicine with multiple pharmacological activities, plays a crucial role in modulating mood disorders. Several recent studies have identified an underlying role of Panax ginseng in the prevention and treatment of depression. However, the cellular and molecular mechanisms remain unclear.

MATERIALS AND METHODS

In this review, we summarized the recent progress of antidepressant effects and underlying mechanisms of Panax ginseng and its representative herbal formulae.

RESULTS

The molecular and cellular mechanisms of Panax ginseng and its herbal formulae include modulating monoamine neurotransmitter system, upregulating the expression of neurotrophic factors, regulating the function of HPA axis, and anti-inflammatory action.

CONCLUSIONS

Therefore, this review may provide theoretical bases and clinical applications for the treatment of depression by Panax ginseng and its representative herbal formulae.

HOMA-IR increase after antidepressant treatment in depressed patients with the Met allele of the Val66Met BDNF genetic polymorphism

BACKGROUND

The brain-derived neurotrophic factor (BDNF) Val66Met polymorphism is associated with response to antidepressant drugs in depressed patients and with metabolic side effects after antipsychotic treatment. This study aims to assess the association between this polymorphism and insulin resistance after antidepressant treatment in depressed patients.

METHODS

One hundred forty-eight Caucasian patients with a current unipolar major depressive episode (DSM IV-TR) were genotyped for the BDNF Val66Met polymorphism and assessed at baseline and after 3 and 6 months of antidepressant treatment for the 'Homoeostasis model assessment of insulin resistance' (HOMA-IR) index, a valid measure of insulin resistance based on fasting plasma insulinaemia and glycaemia. Because validity assumptions were fulfilled, data were analysed using analysis of variance for repeated measures.

RESULTS

The 52 (35%) Met carriers and 96 (65%) Val/Val patients were not different at baseline for clinical characteristics and HOMA-IR. A significant Val66Met × time interaction (p = 0.02), a significant time effect (p = 0.03) and a significant Val66Met effect (p = 0.0497) were shown for HOMA-IR. A significant Val66Met × time interaction (p = 0.01) and a significant time effect (p = 0.003) were shown for fasting glycaemia. HOMA-IR and fasting glycaemia changes after antidepressant treatment were significantly higher in Met carrier than in Val/Val patients (HOMA-IR changes: Met: 0.71 ± 3.29 v. Val/Val: -0.16 ± 1.34, t = 2.3, df = 146, p = 0.02, glycaemia changes: Met: 0.09 ± 0.30 v. Val/Val: 0.02 ± 0.16, t = -2.0, df = 146, p = 0.045).

CONCLUSIONS

The Met allele of the Val66Met BDNF polymorphism confers to depressed patients a higher risk of insulin-resistance after antidepressant treatment. These patients could benefit from specific monitoring of metabolism and preventive measures.

BDNF Genotype and Baseline Serum Levels in Relation to Electroconvulsive Therapy Effectiveness in Treatment-Resistant Depressed Patients

OBJECTIVES

Electroconvulsive therapy (ECT) represents one of the most effective therapies for treatment-resistant depression (TRD). The brain-derived neurotrophic factor (BDNF) is a neurotrophin implicated in major depressive disorder and in the effects of different therapeutic approaches, including ECT. Both BDNF peripheral levels and Val66Met polymorphism have been suggested as biomarkers of treatment effectiveness. The objective of this study was to test the potential of serum BDNF levels and Val66Met polymorphism in predicting ECT outcome in TRD patients.

METHODS

Seventy-four TRD patients scheduled to undergo ECT were included in the study. Illness severity was assessed through the Montgomery and Asberg Depression Rating Scale before beginning ECT (T0), the day after the end of ECT (T1), and 1 month after the end of ECT (T2). At T1, patients were classified as responders/nonresponders and remitters/nonremitters, whereas at T2, they were classified as sustained responders/nonresponders and sustained remitters/nonremitters. Serum concentrations of BDNF were measured at T0, and the BDNF Val66Met polymorphism was genotyped.

RESULTS

No difference in BDNF concentrations was observed in responders versus nonresponders, in remitters versus nonremitters, in sustained responders versus sustained nonresponders, and in sustained remitters versus sustained nonremitters. No association of Val66Met polymorphism was detected with both the response and the remission status.

CONCLUSIONS

Baseline serum BDNF levels and the BDNF Val66Met polymorphism showed no clinical utility in predicting ECT outcome in TRD patients.

Investigating the Contribution of NPSR1, IL-6 and BDNF Polymorphisms to Depressive and Anxiety Symptoms in Hemodialysis Patients

AIMS

Psychological symptoms are prevalent in hemodialysis (HD) patients. Previous investigations showed that brain-derived neurotrophic factor (BDNF) and interleukin-6 (IL-6) as well as the interaction with neuropeptide S receptor 1 (NPSR1) are linked to the development of psychological distress. This study examined the association of polymorphisms of genes encoding these proteins with depression and anxiety in a representative group of Jordanian HD patients.

METHODS

A total of 302 HD patients were involved in the study and categorized into three groups based on the Hospital Anxiety and Depression Scale, HADS-D or HADS-A scores as follows: normal (<7), mild (8-10) and moderate-severe (11-21). Single nucleotide polymorphism (SNP) of NPSR1 Asn107Ile (rs324981), IL-6 G174C (rs1800795), and BDNF Val66Met (rs6265) was genotyped using blood samples.

RESULTS

The frequency of Ile-allele of NPSR1 Asn107Ile was significantly higher in patients with moderate-severe HADS-A scores versus normal (53% vs. 40.8%, p = .035). Using ordinal regression analysis, Asn-allele of NPSR1 polymorphism was nominally significantly associated with a lower risk of anxiety (OR = 0.57, CI: 0.33-0.97, p = .038) after adjusting for other covariates. A marginally significant difference in genotype distribution of IL-6 G174C was observed among patients according to HADS-D scores (p = .05). Furthermore, carriers of IL-6174 CC genotype showed lower median IL-6 serum concentration versus carriers of GG genotype (5.2 vs. 1.35 pg/mL, p < .05).

CONCLUSIONS

The results support the genetic role of NPSR1 in the pathogenesis of anxiety and suggest that carriers of NPSR1 Ile-allele are at increased risk of anxiety in HD patients. Neither BDNF Val66Met nor IL-6 G174C were linked to psychological symptoms. Future studies among other ethnicities are necessary to verify the observations.

Screening of brain-derived neurotrophic factor (BDNF) single nucleotide polymorphisms and plasma BDNF levels among Malaysian major depressive disorder patients

Background

Brain-derived neurotrophic factor (BDNF) is a neurotrophin found in abundance in brain regions such as the hippocampus, cortex, cerebellum and basal forebrain. It has been associated with the risk of susceptibility to major depressive disorder (MDD). This study aimed to determine the association of three BDNF variants (rs6265, rs1048218 and rs1048220) with Malaysian MDD patients.

Methods

The correlation of these variants to the plasma BDNF level among Malaysian MDD patients was assessed. A total of 300 cases and 300 matched controls recruited from four public hospitals within the Klang Valley of Selangor State, Malaysia and matched for age, sex and ethnicity were screened for BDNF rs6265, rs1048218 and rs1048220 using high resolution melting (HRM).

Findings

BDNF rs1048218 and BDNF rs1048220 were monomorphic and were excluded from further analysis. The distribution of the alleles and genotypes for BDNF rs6265 was in Hardy-Weinberg equilibrium for the controls (p = 0.13) but was in Hardy Weinberg disequilibrium for the cases (p = 0.011). Findings from this study indicated that having BDNF rs6265 in the Malaysian population increase the odds of developing MDD by 2.05 folds (95% CI = 1.48–3.65). Plasma from 206 cases and 206 controls were randomly selected to measure the BDNF level using enzyme-linked immunosorbent assay (ELISA). A significant decrease in the plasma BDNF level of the cases as compared to controls (p<0.0001) was observed. However, there was no evidence of the effect of the rs6265 genotypes on the BDNF level indicating a possible role of other factors in modulating the BDNF level that warrants further investigation.

Conclusion

The study indicated that having the BDNF rs6265 allele (A) increase the risk of developing MDD in the Malaysian population suggesting a possible role of BDNF in the etiology of the disorder.

The roles of brain-derived neurotrophic factor (BDNF) and glial cell line-derived neurotrophic factor (GDNF) in predicting treatment remission in a Chinese Han population with generalized anxiety disorder

Neurotrophic factors, particularly brain-derived neurotrophic factor (BDNF) and glial cell line-derived neurotrophic factor (GDNF), are involved in neuroplasticity in the nervous system. To explore the characteristics of BDNF and GDNF and their roles in predicting treatment remission in a Chinese Han population with generalized anxiety disorder (GAD), 85 GAD patients were treated with escitalopram or venlafaxine randomly for 8 weeks. The serum BDNF/GDNF levels were detected, while Hamilton Anxiety Rating Scale (HAMA) scores were measured at baseline and after 8 weeks of treatment. The differences in serum BDNF/GDNF levels between GAD patients (n = 85) and healthy controls (n = 73) and between remission and nonremission were then compared. The serum BDNF levels were lower in GAD patients (1197.24 ± 367.41 µg/L) than in healthy controls (1378.09 ± 382.46 µg/L) (P < 0.05). The serum GDNF levels were also lower in GAD patients (10.19 ± 9.86 µg/L) than in healthy controls (13.73 ± 9.44 µg/L) (P < 0.05). The BDNF level was negatively correlated with baseline HAMA score (P < 0.05). The GDNF level was negatively correlated with baseline HAMA score (P < 0.05). The BDNF level was positively correlated with GDNF level (P < 0.05). Both baseline BDNF/GDNF levels in remission and nonremission showed no statistically significant differences. No significant correlation was found between baseline BDNF level and the HAMA reduction rate or between baseline GDNF levels and the HAMA reduction rate. Both serum BDNF and GDNF were demonstrated to be potential biomarkers of GAD, it seems that serum BDNF and GDNF levels can be used to assess the baseline anxiety severity of GAD but cannot serve as a factor to predict treatment remission.

BDNF plasma levels and genotype in depression and the response to electroconvulsive therapy

BACKGROUND

Brain derived neurotrophic factor (BDNF) has been implicated in the pathophysiology of depression and the antidepressant response. Electroconvulsive therapy (ECT) is reported to increase BDNF levels in blood, though only a small number of studies have been conducted to date.

OBJECTIVE

Our objectives were to: 1) compare plasma BDNF levels in medicated patients with depression and controls; 2) assess the effect of ECT on plasma BDNF levels in medicated patients with depression; 3) explore the relationship between plasma BDNF levels and the Val66Met (rs6265) BDNF polymorphism; and 4) examine the relationship between plasma BDNF levels and clinical symptoms and outcomes with ECT.

METHODS

Plasma BDNF levels were analyzed in samples from 61 medicated patients with a major depressive episode and 50 healthy controls, and in patient samples following a course of ECT. Fifty-two samples from the depressed patient group were genotyped for the Val66Met BDNF polymorphism.

RESULTS

There was no difference in plasma BDNF levels between the control and depressed groups, and there was no difference in plasma BDNF levels in patients following treatment with ECT. In line with previous reports, we show that, in medicated patients with depression, Met-carriers had higher plasma BDNF levels than Val-carriers, though genotype was not related to clinical response. We found no association between plasma BDNF levels and depression severity or the clinical response to ECT.

CONCLUSIONS

Our results suggest that plasma BDNF does not represent a suitable candidate biomarker for determining the therapeutic response to ECT.