BDNF function as a potential mediator of bipolar disorder and post-traumatic stress disorder comorbidity

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.

Correlation of brain-derived neurotrophic factor with severity of depression and treatment response

Background

Brain-derived neurotrophic factor (BDNF) is a modulator of neuroplasticity in the brain. It plays an important role in the pathophysiology of depression through the stress pathway. The information about correlation of BDNF levels with depression severity and treatment response in Indian population is scarce.

Methods

Consecutive 60 never treated cases with depression reporting to a large tertiary care psychiatry unit and 60 healthy matched controls from 01 January 2016 to 31 December 2016 were enrolled for study. Sociodemographic data were collected. Diagnosis of depression was carried out as per International Classification of Diseases-10th revision (ICD-10) diagnostic criteria for research. The Hamilton Rating Scale for Depression (HRSD) was administered and accordingly scored. Venous blood for BDNF levels was collected from all cases and controls. Cases were reassessed after 04 weeks of treatment with HRSD and BDNF levels.

Results

The mean level of serum BDNF among cases (18.56 ng/ml) was found to be reduced significantly as compared with healthy controls (32.41 ng/ml). The mean serum BDNF level (18.56 ng/ml) in never treated cases was significantly negatively correlated with the median clinical HRSD score (18.5). There was a significant increase in the mean level of serum BDNF after antidepressant treatment.

Conclusion

The study has revealed statistically significant low levels of serum BDNF in cases not exposed to treatment with depression compared with healthy controls. There was significant negative correlation of levels of serum BDNF with depression severity. The levels of serum BDNF significantly increased after four weeks of treatment.

Oxytocin receptor genes moderate BDNF epigenetic methylation by childhood trauma

OBJECTIVES

Gene-Environment (G × E) interaction is of increasing importance in understanding the pathophysiology of posttraumatic stress disorder (PTSD). This study investigated the interaction effect of childhood traumatic experience and epigenetic methylation of brain-derived neurotrophic factor (BDNF) and a possible moderating effect of oxytocin receptor (OXTR) gene rs53576.

METHODS

Ninety-nine patients with PTSD and 81 healthy controls (HCs) were recruited. Clinical assessments, including the childhood trauma questionnaire (CTQ) and posttraumatic stress disorder Checklist (PCL) were performed. BDNF methylation and OXTR genotyping (A vs. G allele) were conducted through blood sampling. A two-way multivariate analysis and a moderated regression analysis were conducted to investigate the moderating effect of the OXTR gene on the relationship between CTQ and BDNF methylation.

RESULTS

As for the HC group, the interaction effect of the CTQ and OXTR genotype was significant on BDNF methylation, and the moderation model showed that CTQ and OXTR group are significant predictors of BDNF methylation. In the G-OXTR type, the high CTQ group showed a greater BDNF methylation level. As for the PTSD group, no interaction or moderation effects were found.

LIMITATIONS

The present study did not control the dosage, duration of medications, and different trauma types and the assessment of childhood trauma was based on self-report.

CONCLUSIONS

These results suggested that childhood traumatic experience showed a significant impact on BDNF methylation, and OXTR genes have a moderating effect on this epigenetic mechanism in people who have experienced the childhood traumatic episodes.

Berberine Facilitates Extinction and Prevents the Return of Fear

Exposure to a catastrophic event or intense stimulation can trigger fear memories, and the threatening memories persist even over a lifetime. Exposure therapy is based on extinction learning and is widely used to treat fear-related disorders, but its effect on remote fear memory is modest. Berberine, an isoquinoline alkaloid derived from Coptis chinensis or Berberis spp., has been recently reported to exert a diversity of pharmacological effects on the central nervous system, such as facilitating extinction of drug memory. Here, we explored the effect of berberine on extinction of fear memory using a classical contextual fear conditioning (CFC) paradigm, which is Pavlovian conditioning, can rapidly create fear memories related to contexts. Twenty-four hours or 30 days after CFC training, mice were subjected to context extinction (10 days) to extinguish their behaviors and treated with 12.5 or 25 mg/kg berberine intragastrically 1 or 6 h after each extinction session, followed by reinstatement and spontaneous recovery tests. The results showed that intragastric administration of 25 mg/kg berberine 1 h after extinction significantly promoted the extinction of recent and remote fear memories and prevented reinstatement and spontaneous recovery of extinguished fear in mice. These findings indicate that berberine combined with extinction training could serve as a promising novel avenue for the treatment of fear-related disorders.

Effects of growth hormone-releasing hormone receptor antagonist MIA-602 in mice with emotional disorders: a potential treatment for PTSD

Anxiety and depression have been suggested to increase the risk for post-traumatic stress disorders (PTSD). A link between all these mental illnesses, inflammation and oxidative stress is also well established. Recent behavior studies by our group clearly demonstrate a powerful anxiolytic and antidepressant-like effects of a novel growth hormone releasing hormone (GHRH) antagonist of MIAMI class, MIA-690, probably related to modulatory effects on the inflammatory and oxidative status. In the present work we investigated the potential beneficial effects of MIA-602, another recently developed GHRH antagonist, in mood disorders, as anxiety and depression, and the possible brain pathways involved in its protective activity, in adult mice. MIA-602 exhibited antinflammatory and antioxidant effects in ex vivo and in vivo experimental models, inducing anxiolytic and antidepressant-like behavior in mice subcutaneously treated for 4 weeks. The beneficial effect of MIA-602 on inflammatory and oxidative status and synaptogenesis resulting in anxiolytic and antidepressant-like effects could be related by increases of nuclear factor erythroid 2-related factor 2 (Nrf2) and of brain-derived neurotrophic factor (BDNF) signaling pathways in the hippocampus and prefrontal cortex. These results strongly suggest that GHRH analogs should be tried clinically for the treatment of mood disorders including PTSD.

Association study of BDNF Val66Met gene polymorphism with bipolar disorder and lithium treatment response in Indian population

BACKGROUND

The association of the Val66Met (rs6265) polymorphism in the brain-derived neurotrophic factor (BDNF) gene with bipolar disorder (BD) and response to lithium treatment has been suggested, though inconsistently. The considerable diversity of allele frequency across different populations contributes to this. There is no data from South Asia till date. Hence, we examined the association of this polymorphism in BD cases from India, and its association with lithium treatment response.

METHODS

BD patients (N = 301) were recruited from the clinical services of National Institute of Mental Health and Neurosciences (NIMHANS), India. Lithium treatment response for 190 BD subjects was assessed using Alda scale by NIMH life charts. Patients with total score ⩾7 were defined as lithium responders (N = 115) and patients with score <7 were defined as lithium non-responders (N = 75). Healthy controls (N = 484) with no lifetime history of neuropsychiatric illness or a family history of mental illness were recruited as control set. Genotyping was performed by TaqMan genotyping assay.

RESULTS

Genotype and allele frequency of BDNF Val66Met SNP was significantly different (χ2 = 7.78, p = 0.02) in cases compared to controls, and the Val(G) allele was more frequent (χ2 = 7.08, p = 0.008) in BD patients. However, no significant difference is noted in genotype or allele frequencies of this polymorphism between the lithium responders and non-responders.

CONCLUSIONS

The Val(G) allele of BDNF Val66Met polymorphism is associated with risk of BD in this sample, but it is not related to response to lithium.

Psychologically Traumatic Oxidative Stress; A Comprehensive Review of Redox Mechanisms and Related Inflammatory Implications

The organism's energy requirements for homeostatic balance are covered by the redox mechanisms. Yet in case of psychologically traumatic stress, allostatic regulations activate both pro-oxidant and antioxidant molecules as well as respective components of the inflammatory system. Thus a new setpoint of dynamic interactions among redox elements is reached. Similarly, a multifaceted interplay between redox and inflammatory fields is activated with the mediation of major effector systems such as the immune system, Hypothalamic-Pituitary-Adrenal axis, kynurenine, and the glycaemic regulatory one. In case of sustained and/or intense traumatic stress the prophylactic antioxidant components are inadequate to provide the organism with neuroprotection finally culminating in Oxidative Stress and subsequently to cellular apoptosis. In parallel multiple inflammatory systems trigger and/or are triggered by the redox systems in tight fashion so that the causation sequence appears obscure. This exhaustive review aims at the comprehension of the interaction among components of the redox system as well as to the collection of disperse findings relative to the redox-inflammatory interplay in the context of traumatic stress so that new research strategies could be developed.

The potential role of Piper guineense (black pepper) in managing geriatric brain aging: a review

Brain aging is one of the unavoidable aspects of geriatric life. As one ages, changes such as the shrinking of certain parts (particularly the frontal cortex, which is vital to learning and other complex mental activities) of the brain may occur. Consequently, communications between neurons are less effective, and blood flow to the brain could also decrease. Efforts made at the biological level for repair become inadequate, leading to the accumulation of β-amyloid peptide in the brain faster than its probable degradation mechanism, resulting in cognitive malfunction. Subsequent clinical usage of drugs in battling related brain-aging ailments has been associated with several undesirable side effects. However, recent research has investigated the potential use of natural compounds from food in combating such occurrences. This review provides information about the use of Piper guineense (black pepper) as a possible agent in managing brain aging because of its implications for practical brain function. P. guineense contains an alkaloid (piperine) reported to be an antioxidant, anti-depressant, and central nervous system stimulant. This alkaloid and other related compounds are neuroprotective agents that reduce lipid oxidation and inhibit tangles in the brain tissues.

Omega-3 Rich Oils Attenuate ADHD-Like Behaviour Induced by Dietary Monosodium Glutamate in Rats

&lt;b&gt;Background and Objective:&lt;/b&gt; Attention Deficit Hyperactivity Disorder (ADHD) is a neurodevelopmental disorder characterized by inattention, hyperactivity and cognitive dysfunction. The present study was designed to examine the possible modulatory effect of Fish, Walnuts or Fenugreek Oils against Attention Deficit Hyperactivity Disorder (ADHD)-like Behavior induced by Monosodium Glutamate (MSG) in Rats. &lt;b&gt;Materials and Methods:&lt;/b&gt; Fifty weaning rats were divided into five groups, (each group contain 10 rats) as follows: Group 1: Normal control rats were fed on a balanced diet. Groups from 2-5 rats were fed on a balanced diet+MSG (0.4 g kg&lt;sup&gt;&lt;/sup&gt;&lt;sup&gt;1&lt;/sup&gt; diet), Group 2 served as a positive control group whereas group 3, 4 and 5 treated with Fish, Walnuts and Fenugreek oil, respectively, (200 mg kg&lt;sup&gt;&lt;/sup&gt;&lt;sup&gt;1&lt;/sup&gt; b.wt.) by intra-gastric tube. Biochemical and behavioural parameters were tested as well as microscopic examination of brain tissue was done. &lt;b&gt;Results:&lt;/b&gt; MSG ingestion caused marked disruption in locomotors activity, memory function and brain tissue structure along with significant abnormalities in some bio-markers and reduction in the gene expression level of Bcl-2 in brain tissue. However, treatment with the tested oils showed remarkable effect by reversing the condition. &lt;b&gt;Conclusion:&lt;/b&gt; Dietary supplementation with walnut; fenugreek or fish oils at the tested dose could modulate the condition of ADHD in rats.

Investigating rare pathogenic/likely pathogenic exonic variation in bipolar disorder

Bipolar disorder (BD) is a serious mental illness with substantial common variant heritability. However, the role of rare coding variation in BD is not well established. We examined the protein-coding (exonic) sequences of 3,987 unrelated individuals with BD and 5,322 controls of predominantly European ancestry across four cohorts from the Bipolar Sequencing Consortium (BSC). We assessed the burden of rare, protein-altering, single nucleotide variants classified as pathogenic or likely pathogenic (P-LP) both exome-wide and within several groups of genes with phenotypic or biologic plausibility in BD. While we observed an increased burden of rare coding P-LP variants within 165 genes identified as BD GWAS regions in 3,987 BD cases (meta-analysis OR = 1.9, 95% CI = 1.3-2.8, one-sided p = 6.0 × 10-4), this enrichment did not replicate in an additional 9,929 BD cases and 14,018 controls (OR = 0.9, one-side p = 0.70). Although BD shares common variant heritability with schizophrenia, in the BSC sample we did not observe a significant enrichment of P-LP variants in SCZ GWAS genes, in two classes of neuronal synaptic genes (RBFOX2 and FMRP) associated with SCZ or in loss-of-function intolerant genes. In this study, the largest analysis of exonic variation in BD, individuals with BD do not carry a replicable enrichment of rare P-LP variants across the exome or in any of several groups of genes with biologic plausibility. Moreover, despite a strong shared susceptibility between BD and SCZ through common genetic variation, we do not observe an association between BD risk and rare P-LP coding variants in genes known to modulate risk for SCZ.

Evidence of altered metabolism of cellular membranes in bipolar disorder comorbid with post-traumatic stress disorder

In proton magnetic resonance spectroscopy (¹H MRS) studies, aberrant levels of choline-containing compounds that include glycerophosphocholine plus phosphocholine (GPC+PC), can signify alterations in the metabolism of cellular membrane phospholipids (MPLs) from a healthy baseline. In a recent ¹H MRS study, we reported increased GPC+PC in cortical and subcortical areas of adult patients with bipolar disorder I (BP-I). Post-traumatic stress disorder (PTSD) can worsen the severity of BP-I, but it is unclear whether the effect of a PTSD comorbidity in BP-I is associated with altered MPL metabolism. The purpose of this study was to re-investigate the ¹H MRS data to determine whether the regional extent of elevated GPC+PC was greater in BP-I patients with PTSD (BP-I_/wPTSD) compared to BP-I without comorbid PTSD (BP-I_/woPTSD) patients and healthy controls. GPC+PC levels from four brain areas [the anterior cingulate cortex (ACC), anterior-dorsal ACC, caudate, and putamen] were measured in 14 BP-I_/wPTSD, 36 BP-I_/woPTSD, and 44 healthy controls using a multi-voxel ¹H MRS approach on a 3 Tesla system with high spatial resolution and absolute quantification. Results show a significant increase in GPC+PC levels from the caudate and putamen of BP-I_/wPTSD patients compared to healthy controls (P<0.05) and in the putamen compared to BP-I_/woPTSD patients (P<0.05). These findings are consistent with evidence of elevated degradation of MPLs in the neuropil that is more pronounced in BP-I patients with comorbid PTSD.

Computational analysis of deleterious single nucleotide polymorphisms in catechol O-Methyltransferase conferring risk to post-traumatic stress disorder

Post-traumatic stress disorder (PTSD) is one of the prevalent neurological disorder which is drawing increased attention over the past few decades. Major risk factors for PTSD can be categorized into environmental and genetic factors. Among the genetic risk factors, polymorphisms in the catechol-O-methyltransferase (COMT) gene is known to be associated with the risk for PTSD. In the present study, we analysed the impact of deleterious single nucleotide polymorphisms (SNPs) in the COMT gene conferring risk to PTSD using computational based approaches followed by molecular dynamic simulations. The data on COMT gene associated with PTSD were collected from several databases including Online Mendelian Inheritance in Man (OMIM) search. Datasets related to SNP were downloaded from the dbSNP database. To study the structural and dynamic effects of COMT wild type and mutant forms, we performed molecular dynamics simulations (MD simulations) at a time scale of 300 ns. Results from screening the SNPs using the computational tools SIFT and Polyphen-2 demonstrated that the SNP rs4680 (V158M) in COMT has a deleterious effect with phenotype in PTSD. Results from the MD simulations showed that there is some major fluctuations in the structural features including root mean square deviation (RMSD), radius of gyration (Rg), root mean square fluctuation (RMSF) and secondary structural elements including α-helices, sheets and turns between wild-type (WT) and mutant forms of COMT protein. In conclusion, our study provides novel insights into the deleterious effects and impact of V158M mutation on COMT protein structure which plays a key role in PTSD.

Association of Brain-Derived Neurotrophic Factor rs6265 G>A polymorphism and Post-traumatic Stress Disorder susceptibility: A systematic review and meta-analysis

BACKGROUND

Previous studies have shown that the brain-derived neurotrophic factor (BDNF) rs6265 G > A polymorphism is closely related post-traumatic stress disorder (PTSD) risk. However, the results were not consistent. We therefore conducted a meta-analysis to explore the underlying relationships between BDNF rs6265 G > A polymorphism and PTSD risk.

MATERIALS AND METHODS

Five online databases were searched, and all related studies were reviewed up to July 1, 2020. Odds ratios (ORs) and corresponding 95% confidence intervals (CIs) were calculated to examine the statistical power of each genetic model. In addition, heterogeneity, sensitivity accumulative analysis, and publication bias were examined to check the statistical power.

RESULT

Overall, 16 publications involving 5,369 subjects were included in this systematic review and 11 case-control studies were analyses in meta-analysis. The pooled results indicated an increasing risk of A allele mutations with PTSD risk. Moreover, the sequential subgroup analysis also demonstrated some similar situations in Asian populations and other groups.

CONCLUSION

Current meta-analysis suggests that the BDNF rs6265 G > A polymorphism might be involved in PTSD susceptibility.

Genotype-expression interactions for BDNF across human brain regions

Background

Genetic variations in brain-derived neurotrophic factor (BDNF) are associated with various psychiatric disorders including depression, obsessive-compulsive disorder, substance use disorders, and schizophrenia; altered gene expression triggered by these genetic variants may serve to create these phenotypes. But genotype-expression interactions for this gene have not been well-studied across brain regions relevant for psychiatric disorders.

Results

At false discovery rate (FDR) of 10% (q < 0.1), a total of 61 SNPs were associated with BDNF expression in cerebellum (n = 209), 55 SNPs in cortex (n = 205), 48 SNPs in nucleus accumbens (n = 202), 47 SNPs in caudate (n = 194), and 58 SNPs in cerebellar hemisphere (n = 175). We identified a set of 30 SNPs in 2 haplotype blocks that were associated with alterations in expression for each of these 5 regions. The first haplotype block included variants associated in the literature with panic disorders (rs16917204), addiction (rs11030104), bipolar disorder (rs16917237/rs2049045), and obsessive-compulsive disorder (rs6265). Likewise, variants in the second haplotype block have been previously associated with disorders such as nicotine addiction, major depressive disorder (rs988748), and epilepsy (rs6484320/rs7103411).

Conclusions

This work supports the association of variants within BDNF for expression changes in these key brain regions that may contribute to common behavioral phenotypes for disorders of compulsion, impulsivity, and addiction. These SNPs should be further investigated as possible therapeutic and diagnostic targets to aid in management of these and other psychiatric disorders.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12864-021-07525-1.

Psychedelics in Psychiatry: Neuroplastic, Immunomodulatory, and Neurotransmitter Mechanisms

Mounting evidence suggests safety and efficacy of psychedelic compounds as potential novel therapeutics in psychiatry. Ketamine has been approved by the Food and Drug Administration in a new class of antidepressants, and 3,4-methylenedioxymethamphetamine (MDMA) is undergoing phase III clinical trials for post-traumatic stress disorder. Psilocybin and lysergic acid diethylamide (LSD) are being investigated in several phase II and phase I clinical trials. Hence, the concept of psychedelics as therapeutics may be incorporated into modern society. Here, we discuss the main known neurobiological therapeutic mechanisms of psychedelics, which are thought to be mediated by the effects of these compounds on the serotonergic (via 5-HT_2A and 5-HT_1A receptors) and glutamatergic [via N-methyl-d-aspartate (NMDA) and α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptors] systems. We focus on 1) neuroplasticity mediated by the modulation of mammalian target of rapamycin-, brain-derived neurotrophic factor-, and early growth response-related pathways; 2) immunomodulation via effects on the hypothalamic-pituitary-adrenal axis, nuclear factor ĸB, and cytokines such as tumor necrosis factor-α and interleukin 1, 6, and 10 production and release; and 3) modulation of serotonergic, dopaminergic, glutamatergic, GABAergic, and norepinephrinergic receptors, transporters, and turnover systems. We discuss arising concerns and ways to assess potential neurobiological changes, dependence, and immunosuppression. Although larger cohorts are required to corroborate preliminary findings, the results obtained so far are promising and represent a critical opportunity for improvement of pharmacotherapies in psychiatry, an area that has seen limited therapeutic advancement in the last 20 years. Studies are underway that are trying to decouple the psychedelic effects from the therapeutic effects of these compounds. SIGNIFICANCE STATEMENT: Psychedelic compounds are emerging as potential novel therapeutics in psychiatry. However, understanding of molecular mechanisms mediating improvement remains limited. This paper reviews the available evidence concerning the effects of psychedelic compounds on pathways that modulate neuroplasticity, immunity, and neurotransmitter systems. This work aims to be a reference for psychiatrists who may soon be faced with the possibility of prescribing psychedelic compounds as medications, helping them assess which compound(s) and regimen could be most useful for decreasing specific psychiatric symptoms.

Environmental Risk Factors for Bipolar Disorders and High-Risk States in Adolescence: A Systematic Review

Background and objectives: A deeper comprehension of the role that environmental risk factors play in the development of adolescent Bipolar Disorder (BD), as well as in the evolution of high-risk states for BD, may entangle further prevention and treatment advances. The present systematic review is aimed at critically summarizing evidence about the role that environmental risk factors play in the development of BD in adolescence and their interaction with BD high-risk states. Materials and Methods: MEDLINE/Pubmed, Scopus and Web of Science datasets were systematically searched until 4 September 2020. Original studies that reported information about the role of environmental risk factors in the development of BD during adolescence, or assessing their influence on the development of psychopathology in high-risk states for BD, were considered for inclusion. Two blind researchers performed title/abstract, full-text screening, and hand-screening of relevant references. The risk of bias was assessed by means of the Newcastle-Ottawa Scale. Results: Fourteen studies were included in the review. Negative stressful life events, particularly sexual and physical abuse, but also emotional mistreatment, were associated with more severe psychopathology in adolescents with BD, as well as with higher risk for developing mood disorders in BD offspring. Similar findings were detected for familial environment-related features, such as parental rejection and low perceived care, while no univocal results were found when analyzing familial functioning. Conclusions: The present systematic review confirmed the relevant role that environmental risk factors, particularly negative stressful live events and family-related features, play in the development of BD psychopathology during adolescence. Future studies are expected to clarify possible further environmental factors that may be implicated in the development of BD during youth that may serve as target of prevention and early treatment strategies.

Peripheral blood levels of brain-derived neurotrophic factor in patients with post-traumatic stress disorder (PTSD): A systematic review and meta-analysis

BACKGROUND

Brain-derived neurotrophic factor (BDNF) plays a crucial role in the survival, differentiation, growth, and plasticity of the central nervous system (CNS). Post-traumatic stress disorder (PTSD) is a complex syndrome that affects CNS function. Evidence indicates that changes in peripheral levels of BDNF may interfere with stress. However, the results are mixed. This study investigates whether blood levels of BDNF in patients with post-traumatic stress disorder (PTSD) are different.

METHODS

We conducted a systematic search in the major electronic medical databases from inception through September 2019 and identified Observational studies that measured serum levels of BDNF in patients with PTSD compared to controls without PTSD.

RESULTS

20 studies were eligible to be included in the present meta-analysis. Subjects with PTSD (n = 909) showed lower BDNF levels compared to Non-PTSD controls (n = 1679) (SMD = 0.52; 95% confidence interval: 0.18 to 0.85). Subgroup meta-analyses confirmed higher levels of BDNF in patients with PTSD compared to non-PTSD controls in plasma, not serum, and in studies that used sandwich ELISA, not ELISA, for BDNF measurement. Meta-regressions showed no significant effect of age, gender, NOS, and sample size.

CONCLUSIONS

PTSD patients had increased serum BDNF levels compared to healthy controls. Our finding of higher BDNF levels in patients with PTSD supports the notion that PTSD is a neuroplastic disorder.

Prevalence of childhood trauma among adults with affective disorder using the Childhood Trauma Questionnaire: A meta-analysis

BACKGROUND

Childhood trauma is associated with major depressive disorder (MDD) and bipolar disorder (BD) in adults. However, no meta-analysis was performed on the prevalence of different types of childhood trauma in adults with affective disorders, using the Childhood Trauma Questionnaire (CTQ).

METHODS

Four databases were used to search articles regarding the prevalence of childhood emotional abuse (CEA), childhood physical abuse (CPA), childhood sexual abuse (CSA), childhood physical neglect (CPN), and childhood emotional neglect (CEN) in patients with MDD and BD using the CTQ.

RESULTS

A total of 17 and 11 articles were found analyzing patients with MDD and BD, respectively. A pooled prevalence rate of 33.0% and 30.0% for CEA, 17.0% and 18.0% for CPA, 19.0% and 22.0% for CSA, 37.0% and 31.0% for CEN, and 31% and 30.0% for CPN was found in patients with MDD and BD respectively. A difference in 95% confidence interval in the CSA rate between men and women was found in patients with MDD in the gender subgroup and in the rate of some types of childhood trauma in the continent subgroup in both patient types.

LIMITATIONS

A limited number of articles were included in some continents, thus, the heterogeneity in the meta-analysis was generally high.

CONCLUSION

The prevalence of CEA, CEN, and CPN in patients with affective disorders was relatively high, whereas that of CPA and CSA was relatively low. These childhood traumas might be affected by continent and gender.

A randomized controlled trial comparing the clinical efficacy and cost-effectiveness of eye movement desensitization and reprocessing (EMDR) and integrated EMDR-Dialectical Behavioural Therapy (DBT) in the treatment of patients with post-traumatic stress disorder and comorbid (Sub)clinical borderline personality disorder: study design

BACKGROUND

Comorbidity between Posttraumatic Stress Disorder (PTSD) and Borderline Personality Disorder (BPD) is high. There is growing motivation among clinicians to offer PTSD treatments - such as Eye Movement Desensitization and Reprocessing (EMDR) - to patients with PTSD and comorbid BPD. However, a large subgroup with comorbid BPD does not sufficiently respond to PTSD treatment and is more likely to be excluded or to dropout from treatment. Dialectical Behaviour Therapy (DBT) for BPD is well established and although there is some evidence that DBT combined with DBT Prolonged Exposure (DBT + DBT PE) is twice as effective in reducing PTSD symptoms than DBT alone, the comparative efficacy of integrated PTSD-DBT and PTSD-only treatment has not been investigated yet. The current study will therefore evaluate the comparative clinical efficacy and cost-effectiveness of EMDR-DBT and EMDR-only in patients with PTSD and comorbid (sub)clinical BPD. Moreover, it is not clear yet what treatment works best for which individual patient. The current study will therefore evaluate neurobiological predictors and mediators of the individual response to treatment.

METHOD

A randomized controlled trial comparing the clinical efficacy and cost-effectiveness of integrated EMDR-DBT (n = 63) and EMDR-only (n = 63) in treatment-seeking adult patients with PTSD and comorbid (sub)clinical BPD. In addition, neurobiological predictors and mediators of treatment outcome, such as hair cortisol, FKBP5 and BDNF protein levels and FKBP5 and BDNF methylation status, are measured through hair and blood samples.

DISCUSSION

This is the first study to compare the clinical efficacy and cost-effectiveness of integrated EMDR-DBT and EMDR-only in patients with PTSD and comorbid (sub)clinical BPD, while simultaneously identifying individual predictors and mediators of treatment response. Results will reveal which treatment works best for which individual patient, thereby guiding individual treatment choices and personalizing psychiatry.

TRIAL REGISTRATION

Clinical Trials, NCT03833453 . Retrospectively registered, 15 March 2019.

Predicting stress resilience and vulnerability: brain-derived neurotrophic factor and rapid eye movement sleep as potential biomarkers of individual stress responses

STUDY OBJECTIVES

To examine the rapid eye movement sleep (REM) response to mild stress as a predictor of the REM response to intense stress and brain-derived neurotrophic factor (BDNF) as a potential biomarker of stress resilience and vulnerability.

METHODS

Outbred Wistar rats were surgically implanted with electrodes for recording electroencephalography (EEG) and electromyogram (EMG) and intraperitoneal Data loggers to record body temperature. Blood was also obtained to measure circulating BDNF. After recovery, rats were exposed to mild stress (novel chamber, NC) and later intense stress (shock training, ST), followed by sleep recording. Subsequently, rats were separated into resilient (Res; n=27) or vulnerable (Vul; n = 15) based on whether or not there was a 50% or greater decrease in REM after ST compared to baseline. We then compared sleep, freezing, and the stress response (stress-induced hyperthermia, SIH) across groups to determine the effects of mild and intense stress to determine if BDNF was predictive of the REM response.

RESULTS

REM totals in the first 4 hours of sleep after exposure to NC predicted REM responses following ST with resilient animals having higher REM and vulnerable animals having lower REM. Resilient rats had significantly higher baseline peripheral BDNF compared to vulnerable rats.

CONCLUSIONS

These results show that outbred rats display significant differences in post-stress sleep and peripheral BDNF identifying these factors as potential markers of resilience and vulnerability prior to traumatic stress.

Childhood trauma, psychiatric disorders, and criminality in women: Associations with serum levels of brain-derived neurotrophic factor

Psychiatric disorders and childhood trauma are highly prevalent in female inmates. Brain-derived neurotrophic factor (BDNF) plays a number of roles in neuronal survival, structure, and function. Data in the literature suggest that it is a neurobiological substrate that moderates the impact of childhood adversities on the late expression of psychiatric disorders. The aim of this study was to determine whether five childhood trauma subtypes-physical abuse, sexual abuse, emotional abuse, physical neglect, and emotional neglect-are associated with adult psychiatric disorders, BDNF levels, and criminality among incarcerated women. This was a cross-sectional study involving a consecutive sample of 110 women, divided into three groups of women (forensic - mentally ill who committed crimes, clinical psychiatric inpatients and healthy controls). The Childhood Trauma Questionnaire and the Mini-International Neuropsychiatric Interview-Plus were applied in the whole sample, and BDNF levels were measured in a sub-sample of 54 women. The rates of mental illness and childhood trauma were high in the forensic group. Emotional abuse was higher in the clinical and forensic groups than in the healthy control group. Lower BDNF levels were associated with emotional abuse in the forensic group as well as with sexual abuse in the healthy control group. After multinomial logistic regression, lower levels of BDNF, higher levels of emotional abuse and the presence of familial offense were considered factors related to clinical psychiatric group. The results of this study underscore the idea that BDNF may be an important factor related to the development of diseases and criminality in women who are victims of childhood trauma, becoming a possible biological marker.

Anxiolytic Effect of Alcohol-Water Extracted Suanzaoren-Wuweizi Herb-Pair by Regulating ECS-BDNF-ERK Signaling Pathway Expression in Acute Restraint Stress Male Rats

Herb-pairs are the basic units of composition in Chinese herbal formulae, where the bridge linking Chinese medicine and prescription consists of two Chinese medicine herbs. The Suanzaoren-Wuweizi herb-pair (SWHP) is commonly used as a sedative or tranquilizer. SWHP has been demonstrated to exert an antianxiety effect in animal models of anxiety. However, little information about its mechanism is available and the effects of SWHP have not been investigated. This study examined the effects of SWHP on ameliorating anxiety-like behaviors by regulating endocannabinoids system (ECS)-brain-derived neurotrophic factor (BDNF)-extracellular regulated protein kinases (ERK) signaling pathway expression, induced by restraint stress (RS) procedures. The antianxiety effects of SWHP on RS rats were then examined through the open-field test (OF) and the elevated plus maze test (EPM). The concentration of BNDF, ERK1/2, p-ERK1/2, cAMP-response element binding protein (CREB), and p-CREB expression in the prefrontal cortex and hippocampus of the rats was then measured by western blot. The number of positive cells of CB1 and CB2 in the rats' hippocampus CA1 region was measured by immunohistochemistry. These results gave compelling evidence that SWHP could modify anxiety-like behaviors of RS rats through regulation of the ECS-BDNF-ERK signaling pathway. Our study demonstrated that SWHP improved anxiety-like behaviors in RS rat models by regulating the ECS-BDNF-ERK signaling pathway. The findings indicate that SWHP may have a therapeutic application in the RS model of anxiety disorder, which proposes a potential new direction for research into anxiety disorders regarding mechanisms and the development of novel antianxiety drugs.

Role of DRD2 and ALDH2 genes in bipolar II disorder with and without comorbid anxiety disorder

The presence of comorbid anxiety disorders (AD) and bipolar II disorders (BP-II) compounds disability complicates treatment, worsens prognosis, and has been understudied. The genes involved in metabolizing dopamine and encoding dopamine receptors, such as aldehyde dehydrogenase 2 (ALDH2) and dopamine D2 receptor (DRD2) genes, may be important to the pathogenesis of BP-II comorbid with AD. We aimed to clarify ALDH2 and DRD2 genes for predisposition to BP-II comorbid with and without AD. The sample consisted of 335 subjects BP-II without AD, 127 subjects BP-II with AD and 348 healthy subjects as normal control. The genotypes of the ALDH2 and DRD2 Taq-IA polymorphisms were determined using polymerase chain reactions plus restriction fragment length polymorphism analysis. Logistic regression analysis showed a statistically significant association between DRD2 Taq-I A1/A2 genotype and BP-II with AD (OR = 2.231, P = 0.021). Moreover, a significant interaction of the DRD2 Taq-I A1/A1 and the ALDH2*1*1 genotypes in BP-II without AD was revealed (OR = 5.623, P = 0.001) compared with normal control. Our findings support the hypothesis that a unique genetic distinction between BP-II with and without AD, and suggest a novel association between DRD2 Taq-I A1/A2 genotype and BP-II with AD. Our study also provides further evidence that the ALDH2 and DRD2 genes interact in BP-II, particularly BP-II without AD.

Interaction between job stress, serum BDNF level and the BDNF rs2049046 polymorphism in job burnout

BACKGROUND

Some studies have shown that long-term exposure to job stress could result in burnout, and BDNF polymorphism may play an important role in its psychopathological mechanism. However, the inter-relationships between the job-related stress, serum BDNF level, BDNF genotype and job burnout have not been examined. This study was to explore the job stress × BDNF rs2049046 interaction and the role of serum BDNF level in job burnout in a Chinese Han population.

METHODS

Using a cross-sectional design, 205 healthy subjects were recruited from a public institution in Beijing and assessed for job stress using the House and Rizzo's Work Stress Scale, and job burnout using the Maslach Burnout Inventory (MBI). The BDNF rs2049046 polymorphism was genotyped and serum BDNF (sBDNF) levels were assayed in all of subjects.

RESULTS

The correlations between the job stress score and two burnout subscale scores (emotional exhaustion and cynicism) were significant (both p < 0.001), but not with professional efficacy. There were no significant main effects of the BDNF rs2049046 genotype on burnout, and no significant correlation was observed between sBDNF levels and job burnout. However, the interaction between the job stress and the BDNF rs2049046 genotype (F = 2.709, df = 2, 183, p = 0.032) or between the job stress and sBDNF levels on burnout was significant (t = -2.132, p = 0.035). To be specific, the individuals with the BDNF rs2049046 AT genotype showed a greater susceptibility to the burnout cynicism compared to AA homozygote only in medium-stress group (F = 4.327, df = 1,117, p = 0.015). The individuals who had lower sBDNF showed higher burnout level than those who had higher sBDNF in low-stress group.

CONCLUSIONS

Our findings suggest that the BDNF system may interact with job stress to affect burnout, showing that interaction between BDNF rs2049046 and job stress or the interaction between BDNF levels with work stress on certain burnout dimensions.

Cannabinoids as an Emerging Therapy for Posttraumatic Stress Disorder and Substance Use Disorders

Posttraumatic Stress Disorder (PTSD) is a leading psychiatric disorder that mainly affects military and veteran populations but can occur in anyone affected by trauma. PTSD treatment remains difficult for physicians because most patients with PTSD do not respond to current pharmacological treatment. Psychotherapy is effective, but time consuming and expensive. Substance use disorder is often concurrent with PTSD, which leads to a significant challenge for PTSD treatment. Cannabis has recently received widespread attention for the potential to help many patient populations. Cannabis has been reported as a coping tool for patients with PTSD and preliminary legalization data indicate Cannabis use may reduce the use of more harmful drugs, such as opioids. Rigorous clinical studies of Cannabis could establish whether Cannabis-based medicines can be integrated into treatment regimens for both PTSD and substance use disorder patients.

Genetics of resilience: Implications from genome-wide association studies and candidate genes of the stress response system in posttraumatic stress disorder and depression

Resilience is the ability to cope with critical situations through the use of personal and socially mediated resources. Since a lack of resilience increases the risk of developing stress-related psychiatric disorders such as posttraumatic stress disorder (PTSD) and major depressive disorder (MDD), a better understanding of the biological background is of great value to provide better prevention and treatment options. Resilience is undeniably influenced by genetic factors, but very little is known about the exact underlying mechanisms. A recently published genome-wide association study (GWAS) on resilience has identified three new susceptibility loci, DCLK2, KLHL36, and SLC15A5. Further interesting results can be found in association analyses of gene variants of the stress response system, which is closely related to resilience, and PTSD and MDD. Several promising genes, such as the COMT (catechol-O-methyltransferase) gene, the serotonin transporter gene (SLC6A4), and neuropeptide Y (NPY) suggest gene × environment interaction between genetic variants, childhood adversity, and the occurrence of PTSD and MDD, indicating an impact of these genes on resilience. GWAS on PTSD and MDD provide another approach to identifying new disease-associated loci and, although the functional significance for disease development for most of these risk genes is still unknown, they are potential candidates due to the overlap of stress-related psychiatric disorders and resilience. In the future, it will be important for genetic studies to focus more on resilience than on pathological phenotypes, to develop reasonable concepts for measuring resilience, and to establish international cooperations to generate sufficiently large samples.

The Relationships Between Stress, Mental Disorders, and Epigenetic Regulation of BDNF

Brain-derived neurotrophic factor (BDNF), a critical member of the neurotrophic family, plays an important role in multiple stress-related mental disorders. Although alterations in BDNF in multiple brain regions of individuals experiencing stress have been demonstrated in previous studies, it appears that a set of elements are involved in the complex regulation. In this review, we summarize the specific brain regions with altered BDNF expression during stress exposure. How various environmental factors, including both physical and psychological stress, affect the expression of BDNF in specific brain regions are further summarized. Moreover, epigenetic regulation of BDNF, including DNA methylation, histone modification, and noncoding RNA, in response to diverse types of stress, as well as sex differences in the sensitivity of BDNF to the stress response, is also summarized. Clarification of the underlying role of BDNF in the stress process will promote our understanding of the pathology of stress-linked mental disorders and provide a potent target for the future treatment of stress-related illness.

Post-traumatic stress burden in a sample of hospitalized patients with Bipolar Disorder: Which impact on clinical correlates and suicidal risk?

BACKGROUND

Increasing evidence suggests Bipolar Disorder (BD) to be frequently associated to a history of traumatic experiences and Post-traumatic Stress Disorder (PTSD), with consequent greater symptoms severity, number of hospitalizations and worsening in quality of life. The aim of the present study was to investigate the lifetime exposure to traumatic events and PTSD rates in-patients with BD and to analyze the relationships between PTSD symptoms, clinical characteristics and severity of the mood disorder.

METHODS

A consecutive sample of 212 in-patients with a DSM-5 diagnosis of BD was enrolled at the psychiatric unit of a major University hospital in Italy and assessed by the SCID-5 and MOOD Spectrum-Self Report lifetime version (MOODS-SR). Socio-demographic characteristics, clinical features, substance or alcohol abuse, history of suicide related behaviors were also collected.

RESULTS

Lifetime trauma exposure emerged in 72.3% subjects, with a DSM-5 PTSD diagnosis reported by 35.6%. Patients with PTSD showed more frequently a (hypo)manic episode at onset, alcohol or substance abuse, psychotic features, suicide behaviors, higher scores in almost all the MOODS-SR domains, compared to those without PTSD.

LIMITATIONS

Cross sectional study. Lack of data about the time since trauma exposure or PTSD onset.

CONCLUSIONS

Our findings show a history of multiple traumatic experiences in hospitalized patients with BD besides high rates of PTSD, with the co-occurrence of these conditions appearing to be related to a more severe BD. Detailed investigation of post-traumatic stress symptoms is recommended for the relevant implications on the choice of a tailored treatment and the prognosis assessment.

Effects of COMT rs4680 and BDNF rs6265 polymorphisms on brain degree centrality in Han Chinese adults who lost their only child

Losing one's only child is a major traumatic life event that may lead to posttraumatic stress disorder (PTSD); however, not all parents who experience this trauma develop PTSD. Genetic variants are associated with the risk of developing PTSD. Catechol-O-methyltransferase (COMT) rs4680 and brain-derived neurotrophic factor (BDNF) rs6265 are two most well-described single-nucleotide polymorphisms that relate to stress response; however, the neural mechanism underlying their effects on adults who lost an only child remains poorly understood. Two hundred and ten Han Chinese adults who had lost their only child (55 with PTSD and 155 without PTSD) were included in this imaging genetics study. Participants were divided into subgroups according to their COMT rs4680 and BDNF rs6265 genotypes. Degree Centrality (DC)-a resting-state fMRI index reflecting the brain network communication-was compared with a three-way (PTSD diagnosis, COMT, and BDNF polymorphisms) analysis of covariance. Diagnosis state had a significant effect on DC in bilateral inferior parietal lobules and right middle frontal gyrus (MFG), where PTSD adults showed weaker DC. BDNF × diagnosis interaction effect was found in the right MFG and hippocampus, and these two regions were reversely modulated. Also, there was a significant COMT × BDNF interaction effect in left cuneus, middle temporal gyrus, right inferior occipital gyrus, and bilateral putamen, independent of PTSD diagnosis. These findings suggest that the modulatory effect of BDNF polymorphism on the MFG and hippocampus may contribute to PTSD development in bereaved adults. Interactions of COMT × BDNF polymorphisms modulate some cortices and basal ganglia, irrespective of PTSD development.

A model of human endogenous retrovirus (HERV) activation in mental health and illness

Despite strong evidence for the heritability of major depressive disorder (MDD), efforts to identify causal genes have been disappointing. Furthermore, although there is strong support for life stress as a major predictor of MDD, there are also considerable individual differences in susceptibility and resilience that remain poorly understood. Efforts to identify specific gene-by-environment risk factors produced results that were initially encouraging, but that were not supported by later large-scale studies. Here I propose a novel mechanism that could address the "missing heritability" of MDD, the role of environmental risk factors, and individual differences in susceptibility and resilience. This mechanism focuses on a class of transposable elements, Human Endogenous Retroviruses (HERVs), which make up approximately 8% of the human genome as the result of ancient retroviral infections that entered mammalian germ lines throughout the course of evolution. My primary hypothesis is that exposure to either exogenous viruses or traumatic experiences can activate HERVs in the brain to cause depressive (and possibly other psychiatric) symptoms. My secondary hypothesis is that individual differences in vulnerability or resilience result from the balance of activated HERVs with pathogenic versus protective functions in the brain. Future research can test these hypotheses by analysis of postmortem human brain tissue from donors with known viral or trauma histories; animal studies manipulating HERV expression; cell culture studies examining regulatory mechanisms of HERV expression; and from brain imaging studies of individuals with known HERV-expression. Such research may reveal novel functions of HERVs in neural tissue and may lead to a new generation of psychiatric interventions designed to target aberrant HERV activation.

Genetic predictor of current suicidal ideation in US service members deployed to Iraq and Afghanistan

OBJECTIVE

Suicide is one of the ten leading causes of death in United States and the suicide rate in the military population has increased since the start of the Iraq and Afghanistan wars. However, few biomarkers for current suicidal ideation (CSI) have been identified. The current study examined the association of four candidate genes with CSI in active duty US Army Special Operations Command and National Guard units (n = 3,889) who served in Iraq and Afghanistan between November 2009 and July 2014.

METHODS

Current PTSD symptoms and CSI were assessed using the PTSD Checklist (PCL) and PHQ-9, respectively. Traumatic events were assessed using items from the Life Events Checklist (LEC) that met the DSM-IV PTSD criteria of a traumatic stressor. All genotypes of saliva DNA were discriminated using the TaqMan 5'-exonuclease assay.

RESULTS

The associations between CSI and brain-derived neurotrophic factor (BDNF), FK506 binding protein (FKBP5), catechol-O-methyltransferase (COMT), or S100A10 (p11) were examined. We found CSI was associated with BDNF (OR = 1.5, 95% CI = 1.5-1.8, P = 0.0002), but not FKBP5, COMT and p11. Female soldiers reported CSI more often than males (χ2 = 7.403, p = 0.0065), although gender did not affect CSI severity. In addition, associations were found between CSI and depression, PTSD, and BDNF, but not traumatic events. The BDNF Val66Met contributed to the severity of CSI even after adjusting to PTSD, depression and LEC.

CONCLUSIONS

The associations of BDNF with CSI and its severity suggest that BDNF may be a predictor of suicidal risk and present an opportunity to develop laboratory tools with clinical implications in suicide prevention and treatment.

Increased 5-HT2C receptor editing predisposes to PTSD-like behaviors and alters BDNF and cytokines signaling

Post-traumatic stress disorder (PTSD) is a trauma- and stress-related disorder with dysregulated fear responses and neurobiological impairments, notably at neurotrophic and inflammation levels. Understanding the mechanisms underlying this disease is crucial to develop PTSD models that meet behavioral and neurobiological validity criteria as well as innovative therapeutic approaches. Serotonin 2C receptors (5-HT2CR) are known for their important role in anxiety, and mice having only the fully edited VGV isoform of 5-HT2CR, which thereby overexpressed brain 5-HT2CR, are of special interest to study PTSD predisposition. Innate and conditioned fear-related behaviors were assessed in VGV and wild-type mice. mRNA expression of brain-derived neurotrophic factor (BDNF), tissue-plasminogen activator (tPA), and pro-inflammatory cytokines (IL-6, IL-1β, and calcineurin) were measured by qRT-PCR. The effect of acute and chronic paroxetine was evaluated on both behavior and gene expression. VGV mice displayed greater fear expression, extensive fear extinction deficits, and fear generalization. Paroxetine restored fear extinction in VGV mice when administered acutely and decreased innate fear and fear generalization when administered chronically. In parallel, Bdnf, tPA, and pro-inflammatory cytokines mRNA levels were dysregulated in VGV mice. Bdnf and tPA mRNA expression was decreased in the hippocampus but increased in the amygdala, and chronic paroxetine normalized Bdnf mRNA levels both in the amygdala and the hippocampus. Amygdalar calcineurin mRNA level in VGV mice was also normalized by chronic paroxetine. VGV-transgenic mice displayed behavioral and neurobiological features that could be accessory to the investigation of PTSD and its treatment. Furthermore, these data point out to the role of 5-HT2CR in neuroplasticity and neuroinflammation.

The clinical applications and practical relevance of human conditioning paradigms for posttraumatic stress disorder

The classical conditioning paradigm of fear learning has spawned a number of experimental variations for the explanation of posttraumatic stress disorder (PTSD) etiology. These paradigms include extinction learning and recall, fear inhibition, fear generalization, and conditioned avoidance. As such, each of these paradigms have significant applications for understanding the development, maintenance, treatment, and relapse of the fear-related features of PTSD. In the present review, we describe each of these conditioning-based paradigms with reference to the clinical applications, and supported by case examples from patients with severe PTSD symptoms. We also review the neurobiological models of conditioning and extinction in animals, psychiatrically healthy humans, and PTSD patients, and discuss the current balance of evidence suggesting a number of biological, behavioral, and cognitive mechanisms/moderators of the conditioning and extinction process in experimental and clinical contexts.

The interaction of BDNF Val66Met, PTSD, and child abuse on psychophysiological reactivity and HPA axis function in a sample of Gulf War Veterans

INTRODUCTION

While the BDNF Val66Met polymorphism has been linked to various psychological disorders, limited focus has been on its relationship to posttraumatic stress disorder (PTSD) and early traumas such as child abuse. Therefore, we assessed whether Val66Met was associated with fear potentiated psychophysiological response and HPA axis dysfunction and whether PTSD status or child abuse history moderated these outcomes in a sample of Veterans.

METHODS

226 and 173 participants engaged in a fear potentiated acoustic startle paradigm and a dexamethasone suppression test (DST) respectively. Fear conditions included no, ambiguous, and high threat conditions. Psychophysiological response measures included electromyogram (EMG), skin conductance response (SCR), and heart rate. The Clinician Administered PTSD Scale (CAPS) and the Trauma History Questionnaire (THQ) were used to assess PTSD status and child abuse history respectively.

RESULTS

Met allele carriers exhibited greater SCR magnitudes in the no and ambiguous threat conditions (p < 0.01 and p < 0.05 respectively). Met carriers with PTSD exhibited greater physiological response magnitudes in the ambiguous (SCR, p < 0.001) and high threat conditions (SCR and heart rate, both p ≤ 0.005). Met carrier survivors of child abuse exhibited blunted heart rate magnitudes in the high threat condition (p < 0.01). Met allele carries with PTSD also exhibited greater percent cortisol suppression (p < 0.005).

LIMITATIONS

Limitations included small sample size and the cross-sectional nature of the data.

CONCLUSIONS

The Val66met may impact PTSD susceptibility differentially via enhanced threat sensitivity and HPA axis dysregulation. Child abuse may moderate Val66Met's impact on threat reactivity. Future research should explore how neuronal mechanisms might mediate this risk.

Chemogenetic Manipulation of Dorsal Hippocampal Astrocytes Protects Against the Development of Stress-enhanced Fear Learning

Maladaptive behavioral outcomes following stress have been associated with immune dysregulation. For example, we have previously reported that stress-induced dorsal hippocampal interleukin-1β signaling is critical to the development of stress-enhanced fear learning (SEFL). In parallel, astroglial signaling has been linked to the development of post-traumatic stress disorder (PTSD)-like phenotypes and our most recent studies have revealed astrocytes as the predominant cellular source of stress-induced IL-1β. Here, we used chemogenetic technology and morphological analyses to further explore dorsal hippocampal astrocyte function in the context of SEFL. Using a glial-expressing DREADD construct (AAV8-GFAP-hM4Di(Gi)-mCherry), we show that dorsal hippocampal astroglial G_i activation is sufficient to attenuate SEFL. Furthermore, our data provide the first initial evidence to support the function of the glial-DREADD construct employed. Specifically, we find that CNO (clozapine-n-oxide) significantly attenuated colocalization of the G_i-coupled DREADD receptor and cyclic adenosine monophosphate (cAMP), indicating functional inhibition of cAMP production. Subsequent experiments examined dorsal hippocampal astrocyte volume, surface area, and synaptic contacts (colocalization with postsynaptic density 95 (PSD95)) following exposure to severe stress (capable of inducing SEFL). While severe stress did not alter dorsal hippocampal astrocyte volume or surface area, the severe stressor exposure reduced dorsal hippocampal PSD95 immunoreactivity and the colocalization analysis showed reduced PSD95 colocalized with astrocytes. Collectively, these data provide evidence to support the functional efficacy of the glial-expressing DREADD employed, and suggest that an astrocyte-specific manipulation, activation of astroglial G_i signaling, is sufficient to protect against the development of SEFL, a PTSD-like behavior.

Changes in Brain-Derived Neurotrophic Factor Expression Influence Sleep-Wake Activity and Homeostatic Regulation of Rapid Eye Movement Sleep

Study Objectives

Brain-derived neurotrophic factor (BDNF) expression and homeostatic regulation of rapid eye movement (REM) sleep are critical for neurogenesis and behavioral plasticity. Accumulating clinical and experimental evidence suggests that decreased BDNF expression is causally linked with the development of REM sleep-associated neuropsychiatric disorders. Therefore, we hypothesize that BDNF plays a role in sleep–wake (S–W) activity and homeostatic regulation of REM sleep.

Methods

Male and female wild-type (WT; BDNF +/+) and heterozygous BDNF (KD; BDNF +/−) rats were chronically implanted with S–W recording electrodes to quantify baseline S–W activity and REM sleep homeostatic regulatory processes during the light phase.

Results

Molecular analyses revealed that KD BDNF rats had a 50% decrease in BDNF protein levels. During baseline S–W activity, KD rats exhibited fewer REM sleep episodes that were shorter in duration and took longer to initiate. Also, the baseline S–W activity did not reveal any sex difference. During the 3-hour selective REM sleep deprivation, KD rats failed to exhibit a homeostatic drive for REM sleep and did not exhibit rebound REM sleep during the recovery S–W period.

Conclusion

Interestingly, both genotypes did not reveal any sex difference in the quality and/or quantity of REM sleep. Collectively, these results, for the first time, unequivocally demonstrate that an intact BDNF system in both sexes is a critical modulator for baseline and homeostatic regulation of REM sleep. This study further suggests that heterozygous BDNF knockdown rats are a useful animal model for the study of the cellular and molecular mechanisms of sleep regulation and cognitive functions of sleep.

Hippocampal BDNF in physiological conditions and social isolation

Exposure of an organism to chronic psychosocial stress may affect brain-derived neurotrophic factor (BDNF) expression that has been implicated in the etiology of psychiatric disorders, such as depression. Given that depression in humans has been linked with social stress, the chronic social stress paradigms for modeling psychiatric disorders in animals have thus been developed. Chronic social isolation in animal models generally causes changes in hypothalamic-pituitary-adrenal axis functioning, associated with anxiety- and depressive-like behaviors. Also, this chronic stress causes downregulation of BDNF protein and mRNA in the hippocampus, a stress-sensitive brain region closely related to the pathophysiology of depression. In this review, we discuss the current knowledge regarding the structure, function, intracellular signaling, inter-individual differences and epigenetic regulation of BDNF in both physiological conditions and depression and changes in corticosterone levels, as a marker of stress response. Since BDNF levels are age dependent in humans and rodents, this review will also highlight the effects of adolescent and adult chronic social isolation models of both genders on the BDNF expression.

Brain-Derived Neurotropic Factor Val66Met Polymorphism and Posttraumatic Stress Disorder among Survivors of the 1998 Dongting Lake Flood in China

OBJECTIVE

This study mainly aimed to explore the association between brain-derived neurotropic factor (BDNF) Val66Met polymorphism and posttraumatic stress disorder (PTSD) among flood survivors in China.

METHODS

Individuals who experienced the 1998 Dongting Lake flood in Southeast Huarong, China, were enrolled in this study. Qualified health personnel carried out face-to-face interviews with participants. PTSD was identified using PTSD Checklist-Civilian version (PCL-C). Blood samples were collected from the participants to extract DNA for genotyping.

RESULTS

A total of 175 participants were enrolled in this study. The prevalence of PTSD among flood survivors at 17-year follow-up was 16.0% (28/175). Individuals with PTSD were more likely to be female, experience at least three flood-related stressors, experience at least three postflood stressors, and carry the Met than those without PTSD. Compared with Val/Val homozygotes, Met carriers had higher scores of PCL-C (mean ± standard error: 23.60 ± 7.23 versus 27.19 ± 9.48, P < 0.05). Multivariable logistic regression analysis indicated that Met carriers (aOR = 4.76, 95% CI = 1.02-22.15, P < 0.05) were more likely to develop PTSD than Val/Val homozygotes.

CONCLUSIONS

Met carriers for BDNF rs6265 are at higher risk of developing PTSD and also exhibit more severe PTSD symptoms than Val/Val homozygotes among flood survivors in China.

Clinical correlates of plasma brain-derived neurotrophic factor in post-traumatic stress disorder spectrum after a natural disaster

Clinical correlates of plasma Brain-Derived Neurotrophic Factor (BDNF) have been investigated in a clinical population with Post Traumatic Stress Disorder (PTSD) symptoms and healthy control subjects who survived to the L'Aquila 2009 earthquake. Twenty-six outpatients and 14 control subjects were recruited. Assessments included: Structured Clinical Interview for DSM-IV Axis-I disorders Patient Version, Trauma and Loss Spectrum-Self Report (TALS-SR) for post-traumatic spectrum symptoms. Thirteen patients were diagnosed as Full PTSD and 13 as Partial PTSD. The subjects with full-blown PTSD showed lower BDNF level than subjects with partial PTSD and controls. Different relationship patterns of BDNF with post-traumatic stress spectrum symptoms have been reported in the three samples. Our findings add more insight on the mechanisms regulating BDNF levels in response to stress and further proofs of the utility of the distinction of PTSD into full and partial categories.

Activation of Sigma-1 receptor ameliorates anxiety-like behavior and cognitive impairments in a rat model of post-traumatic stress disorder

Among learning and memory processes, fear memories are crucial in some psychiatric disorders like post-traumatic stress disorder (PTSD). Accumulating evidence shows that the sigma-1 receptor (Sig-1R) has comprehensive involvement in cognitive impairment and neuroprotective effects. It has also been reported that BDNF appears to enhance extinction of fear in anxiety disorders via the MAPK signaling cascade. However, it remains unclear whether BDNF-TrkB-MAPK pathway may be mechanistically involved in the therapeutic effect of sigma-1 receptor in the development of PTSD. To address this question, rats were subjected to a classical single-prolonged stress procedure (SPS) and kept undisturbed for 7 days. After that, rats were re-stressed by re-exposure to the forced swim component of SPS (RSPS). Behavior tests were subsequently performed to assess anxiety and cognitive impairments. Furthermore, we analyzed the expression of BDNF and the phosphorylation of TrkB and three MAPK pathways, namely, the ERK, JNK and p38. We found that the levels of BDNF and p-TrkB were increased following the RSPS procedure, which were reversed by the administration of PRE-084. Meanwhile, among the three MAPK signaling pathways, only the p-ERK expression was increased following the RSPS procedure. Collectively, our results indicate that BDNF-TrkB-ERK signaling pathway may be involved in the activation of sigma-1 receptor to yield therapeutic benefits for PTSD.

The centrality of fear extinction in linking risk factors to PTSD: A narrative review

Recent prospective studies in emergency services have identified impaired fear extinction learning and memory to be a significant predictor of Posttraumatic Stress Disorder (PTSD), complementing a wealth of cross-sectional evidence of extinction deficits associated with the disorder. Additional fields of research show specific risk factors and biomarkers of the disorder, including candidate genotypes, stress and sex hormones, cognitive factors, and sleep disturbances. Studies in mostly nonclinical populations also reveal that the aforementioned factors are involved in fear extinction learning and memory. Here, we provide a comprehensive narrative review of the literature linking PTSD to these risk factors, and linking these risk factors to impaired fear extinction. On balance, the evidence suggests that fear extinction may play a role in the relationship between risk factors and PTSD. Should this notion hold true, this review carries important implications for the improvement of exposure-based treatments, as well as strategies for the implementation of treatment.

Post-traumatic stress disorder risk and brain-derived neurotrophic factor Val66Met

Brain-derived neurotrophic factor (BDNF), which regulates neuronal survival, growth differentiation, and synapse formation, is known to be associated with depression and post-traumatic stress disorder (PTSD). However, the molecular mechanism for those mental disorders remains unknown. Studies have shown that BDNF is associated with PTSD risk and exaggerated startle reaction (a major arousal manifestation of PTSD) in United States military service members who were deployed during the wars in Iraq and Afghanistan. The frequency of the Met/Met in BDNF gene was greater among those with PTSD than those without PTSD. Among individuals who experienced fewer lifetime stressful events, the Met carriers have significantly higher total and startle scores on the PTSD Checklist than the Val/Val carriers. In addition, subjects with PTSD showed higher levels of BDNF in their peripheral blood plasma than the non-probable-PTSD controls. Increased BDNF levels and startle response were observed in both blood plasma and brain hippocampus by inescapable tail shock in rats. In this paper, we reviewed these data to discuss BDNF as a potential biomarker for PTSD risk and its possible roles in the onset of PTSD.

The BDNF Valine 68 to Methionine Polymorphism Increases Compulsive Alcohol Drinking in Mice That Is Reversed by Tropomyosin Receptor Kinase B Activation

BACKGROUND

The valine 66 to methionine (Met) polymorphism within the brain-derived neurotrophic factor (BDNF) sequence reduces activity-dependent BDNF release and is associated with psychiatric disorders in humans. Alcoholism is one of the most prevalent psychiatric diseases. Here, we tested the hypothesis that this polymorphism increases the severity of alcohol abuse disorders.

METHODS

We generated transgenic mice carrying the mouse homolog of the human Met66BDNF allele (Met68BDNF) and used alcohol-drinking paradigms in combination with viral-mediated gene delivery and pharmacology.

RESULTS

We found that Met68BDNF mice consumed excessive amounts of alcohol and continued to drink despite negative consequences, a hallmark of addiction. Importantly, compulsive alcohol intake was reversed by overexpression of the wild-type valine68BDNF allele in the ventromedial prefrontal cortex of the Met68BDNF mice or by systemic administration of the tropomyosin receptor kinase B agonist, LM22A-4.

CONCLUSIONS

Our findings suggest that carrying this BDNF allele increases the risk of developing uncontrolled and excessive alcohol drinking that can be reversed by directly activating the BDNF receptor, tropomyosin receptor kinase B. Importantly, this work identifies a potential therapeutic strategy for the treatment of compulsive alcohol drinking in humans carrying the Met66BDNF allele.

Gene expression in the aging human brain: an overview

PURPOSE OF REVIEW

The review aims to provide a summary of recent developments in the study of gene expression in the aging human brain.

RECENT FINDINGS

Profiling differentially expressed genes or 'transcripts' in the human brain over the course of normal aging has provided valuable insights into the biological pathways that appear activated or suppressed in late life. Genes mediating neuroinflammation and immune system activation in particular, show significant age-related upregulation creating a state of vulnerability to neurodegenerative and neuropsychiatric disease in the aging brain. Cellular ionic dyshomeostasis and age-related decline in a host of molecular influences on synaptic efficacy may underlie neurocognitive decline in later life. Critically, these investigations have also shed light on the mobilization of protective genetic responses within the aging human brain that help determine health and disease trajectories in older age. There is growing interest in the study of pre and posttranscriptional regulators of gene expression, and the role of noncoding RNAs in particular, as mediators of the phenotypic diversity that characterizes human brain aging.

SUMMARY

Gene expression studies in healthy brain aging offer an opportunity to unravel the intricately regulated cellular underpinnings of neurocognitive aging as well as disease risk and resiliency in late life. In doing so, new avenues for early intervention in age-related neurodegenerative disease could be investigated with potentially significant implications for the development of disease-modifying therapies.

Does BDNF Val66Met Polymorphism Confer Risk for Posttraumatic Stress Disorder?

BACKGROUND

Evidence has indicated that BDNF (brain-derived neurotrophic factor) Val66Met genetic variant could be linked to the development of posttraumatic stress disorder (PTSD). However, clinical observations studying the BDNF polymorphism and the risk of PTSD yielded contradictory results. In this meta-analysis we evaluated the association between BDNF Val66Met and PTSD risk.

METHOD

Systematic searches in online databases retrieved 6 relevant publications. Different inherited models were utilized to perform the pooled analysis. Subgroup analyses and sensitive analyses based on Hardy-Weinberg equilibrium (HWE) test results were also carried out.

RESULTS

Our study did not found a significant overall effect of BDNF Val66Met on the susceptibility to PTSD under various genetic models. In contrast, subgroup analyses suggested that the stress status of the control group, but not ethnicity, may influence the relationship of BDNF Val66Met with PTSD risk. After the exclusion of a study that was not in HWE, our conclusions remained unchanged during the influence analyses.

CONCLUSIONS

This meta-analysis suggested no genetic association of BDNF Val66Met with vulnerability to PTSD. Further research studies are warranted to clarify the impact of BDNF variants on the occurrence of PTSD.

Neither cortisol nor brain-derived neurotrophic factor is associated with serotonin transporter in bipolar disorder

Converging evidence indicates the hypothalamus-pituitary-adrenal axis and serotonergic neurons exert reciprocal modulatory actions. Likewise, brain-derived neurotrophic factor (BDNF) has been implicated as a growth and differentiation factor in the development of serotonergic neurons. The aim of this study was to examine the interaction of cortisol and BDNF on serotonin transporter (SERT) in bipolar disorder (BD). Twenty-eight BD and 28 age- and gender-matched healthy controls (HCs) were recruited. (123)I-ADAM with single-photon emission computed tomography (SPECT) was applied for measurement of SERT availability in the brain, which included the midbrain, thalamus, putamen and caudate. Ten milliliters of venous blood was withdrawn, when the subject underwent SPECT, for the measurement of the plasma concentration of cortisol and BDNF. SERT availability was significantly decreased in the midbrain and caudate of BD compared with HCs, whereas plasma concentration of cortisol and BDNF did not show a significant difference. The linear mixed-effect model revealed that there was a significant interaction of group and cortisol on SERT availability of the midbrain, but not BDNF. Linear regression analyses by groups revealed that cortisol was associated with SERT availability in the midbrain in the HCs, but not in BD. Considering previous studies, which showed a significant association of cortisol with SERT availability in the HCs and major depressive disorder (MDD), our result replicated a similar finding in HCs. However, the negative finding of the association of cortisol and SERT availability in BD, which was different from MDD, suggests a different role for cortisol in the pathophysiology of mood disorder.

Development of a cost-efficient novel method for rapid, concurrent genotyping of five common single nucleotide polymorphisms of the brain derived neurotrophic factor (BDNF) gene by tetra-primer amplification refractory mutation system

Brain derived neurotrophic factor (BDNF) is a molecular trophic factor that plays a key role in neuronal survival and plasticity. Single nucleotide polymorphisms (SNPs) of the BDNF gene have been associated with specific phenotypic traits in a large number of neuropsychiatric disorders and the response to psychotherapeutic medications in patient populations. Nevertheless, due to study differences and occasionally contrasting findings, substantial further research is required to understand in better detail the association between specific BDNF SNPs and these psychiatric disorders. While considerable progress has been made recently in developing advanced genotyping platforms of SNPs, many high-throughput probe- or array-based detection methods currently available are limited by high costs, slow processing times or access to advanced instrumentation. The polymerase chain reaction (PCR)-based, tetra-primer amplification refractory mutation system (T-ARMS) method is a potential alternative technique for detecting SNP genotypes efficiently, quickly, easily, and cheaply. As a tool in psychopathology research, T-ARMS was shown to be capable of detecting five common SNPs in the BDNF gene (rs6265, rs988748, rs11030104, 11757G/C and rs7103411), which are all SNPs with previously demonstrated clinical relevance to schizophrenia and depression. The present technique therefore represents a suitable protocol for many research laboratories to study the genetic correlates of BDNF in psychiatric disorders. Copyright Copyright © 2015 John Wiley & Sons, Ltd.

Insulin-like growth factor 2 mitigates depressive behavior in a rat model of chronic stress

Depression is a common psychiatric disorder associated with chronic stress. Insulin-like growth factor 2 (IGF2) is a growth factor that serves important roles in the brain during development and at adulthood. Here, the role of IGF2 expression in the hippocampus was investigated in a rat model of depression. A chronic restraint stress (CRS) model of depression was established in rats, exhibiting depression-like behavior as assessed with the sucrose preference test (SPT) and forced swimming test (FST), and with evaluation of the corticosterone levels. Hippocampal IGF2 levels were significantly lower in rats suffering CRS than in controls, as were levels of pERK1/2 and GluR1. Lentivirus-mediated hippocampal IGF2 overexpression alleviated depressive behavior in restrained rats, elevated the levels of pERK1/2 and GluR1 proteins, but it did not affect the expression of pGSK3β, GluR2, NMDAR1, and NMDAR2A. These results suggest the chronic restraint stress induces depressive behavior, which may be mediated by ERK-dependent IGF2 signaling, pointing to an antidepressant role for this molecular pathway.

Presence of psychological distress symptoms associated with onset-related life events in patients with treatment-refractory depression

BACKGROUND

Previous studies have reported that various non-life-threatening life events could cause psychological distress symptoms like posttraumatic stress disorder in adults and adolescents. We examined whether patients with treatment-refractory depression (TRD) perceive their experiences of life events, of which they think as triggering the onset of depression, as more serious psychological distress symptoms than remitted or mildly symptomatic patients with major depressive disorder (MDD).

METHODS

This study employed a cross-sectional design. We recruited 78 outpatients consisting of 31 TRD patients, 31 remitted MDD patients, and 16 mildly symptomatic MDD patients. We adopted the Impact of Event Scale-Revised (IES-R) to assess the severity of psychological distress symptoms associated with the events that patients thought as triggering the onset of depression. We also evaluated clinical features and variables including the Hamilton Depression Rating Scale (HDRS).

RESULTS

The mean [±SD] score of the IES-R in patients with TRD (46.7 [15.1]) was significantly higher than in remitted (10.3 [9.9], p<0.001) or mildly symptomatic (31.3 [7.7], p<0.001) patients with MDD. The HDRS scores showed significant correlations with those of the IES-R among all patients (r=0.811).

LIMITATIONS

This study was not able to exclude the possibility that the severity of psychological distress symptoms associated with onset-related events could influence the difficult therapeutic course in patients with TRD due to the cross-sectional design.

CONCLUSIONS

This study demonstrated that patients with TRD perceive their onset-related life events as serious psychological distress symptoms. This result contributes to understanding the pathophysiology of TRD.