BDNF serum levels in subjects developing or not post-traumatic stress disorder after trauma exposure

Effects of altered neurotransmitter Glu and GABA on post-traumatic stress disorder in rats

OBJECTIVE

Investigate the role of changes in glutamic acid (Glu), gamma-aminobutyric acid (GABA), and imbalances in Glu-to-GABA ratio (GGR) in the pathogenesis of post-traumatic stress disorder (PTSD).

METHODS

Male Sprague-Dawley rats were randomly assigned to four groups: control, PTSD, PTSD+monosodium glutamate (MSG), and PTSD+lamotrigine (LTG). The PTSD model was established using the single prolonged stress (SPS) method. Rats in the PTSD+MSG and PTSD+LTG groups received MSG and LTG via gavage, respectively. At weeks 1, 2, and 4 after successful PTSD modeling, the Morris water maze (MWM) test and open field test (OFT) were conducted. Concurrently, serum concentrations of corticosterone (CORT), epinephrine, brain-derived neurotrophic factor (BDNF), Glu, and GABA were measured. Moreover, the changes of Glu, GABA and Calcium/calmodulin-dependent protein kinase II (CAMK II) in the hippocampus were also determined.

RESULTS

In the PTSD+MSG group, the GGR in both serum and hippocampus was elevated, whereas in the PTSD+LTG group, it was decreased. In the PTSD+LTG group, the content of CAMK II in the hippocampal tissue of rats was significantly increased (p < 0.01), while serum CORT and BDNF levels were reduced (p < 0.05). The change of GGR can affect the learning and spatial memory abilities, the level of spontaneous activity and the blood biochemical indexes of rats with PTSD.

CONCLUSION

Significant alterations in the GGR reflect neurotransmitter imbalances, which can influence the pathophysiology of PTSD. Targeted neurotransmitter supplementation or antagonistic therapies may help alleviate PTSD symptoms.

Longitudinal associations between early post-injury serum BDNF levels and the development of post-traumatic stress disorder over two years

BACKGROUND

This study investigated the longitudinal associations between serum BDNF (sBDNF) levels measured early after injury and the onset of post-traumatic stress disorder (PTSD) across two years.

METHODS

Patients with moderate to severe physical injuries were enrolled from a trauma center. At baseline, sBDNF levels were measured and a comprehensive socio-demographic and clinical data were collected. The range of time from physical injuries to blood collection was 1-28 days, with a median (IQR) of 8.0 (6.0) days. PTSD diagnoses were determined at 3, 6, 12, and 24 months post-injury using the CAPS-5. Linear regression analyses assessed the relationship between sBDNF levels and PTSD diagnoses.

RESULTS

Out of 923 patients, 112 (12.1 %) developed PTSD during the study. Prevalence rates were 8.8 % at 3 months, 7.6 % at 6 months, 4.8 % at 12 months, and 3.7 % at 24 months. Significantly, lower sBDNF levels were associated with PTSD at 12 and 24 months, after adjusting for covariates and applying Bonferroni corrections, but not at earlier assessments.

LIMITATIONS

Focusing on patients with moderate to severe injuries from a single center may limit the findings' generalizability.

CONCLUSION

Early post-injury sBDNF levels are predictive biomarkers for PTSD, especially significant at 12 and 24 months post-injury.

Natural polyphenols as therapeutic candidates for mitigating neuropsychiatric symptoms in post-traumatic stress disorder: Evidence from preclinical studies

Post-traumatic stress disorder (PTSD) is a challenging mental health condition that affects millions of people worldwide after they experience traumatic events. The current medications often do not fully address the wide range of PTSD symptoms or the underlying brain mechanisms, prompting the need to explore new treatments. Polyphenols, which are natural compounds found in many plant-based foods, have gained interest due to their brain-protective, anti-inflammatory, and antioxidant benefits. This review looks at how polyphenols might help treat PTSD by influencing important brain pathways related to the disorder. We explored how polyphenols affect the stress-response system, fear-related memories, brain chemicals, and inflammation. Specifically, we discuss how compounds like resveratrol, curcumin, green tea extract, and quercetin can balance stress hormones, help reduce fear memories, regulate brain chemicals, and decrease brain inflammation. Studies with animals have provided insights into how these compounds might work to ease PTSD symptoms. Based on the preclinical studies, the present review suggests that polyphenols could be a valuable addition or alternative to current PTSD treatments. However, more research is needed to confirm these findings and to determine the best ways to use polyphenols in treating PTSD.

Effects of high intensity interval training on serum brain-derived neurotrophic factor in individuals with PTSD

BACKGROUND

Brain-derived neurotrophic factor (BDNF) is a protein important for synaptic plasticity and formation of memory. It is suggested to play an important role in the development of psychiatric disorders like post-traumatic stress disorder (PTSD). Individuals with PTSD usually show decreased BDNF levels in serum. Physical exercise has shown to be effective in increasing serum BDNF levels.

OBJECTIVE

As the most beneficial form of exercise to raise serum BDNF levels in individuals with PTSD is yet to be determined, we compared two training protocols and their effects on BDNF release. We expected that a training with higher intensity increases BDNF serum levels more than a low intensity training (LIT).

METHOD

40 participants (80% female) diagnosed with PTSD were randomized to either high-intensity interval training (HIIT) or a low intensity training group (LIT). They underwent a 12-day training period. We measured serum BDNF levels pre- and post-exercise on first and last intervention day. BDNF was controlled for platelet counts.

RESULTS

In the HIIT group there was a significant increase in serum BDNF post-exercise on both days measured, respectively when controlled for platelets. The increase was transient. Both groups did not show an increase in serum BDNF over the course of the 12-day training period.

CONCLUSION

A single session of HIIT raised serum BDNF levels in individuals with PTSD transiently. Neither HIIT nor LIT raised serum BDNF levels over the course of 12 days.

Ketamine alleviates fear memory and spatial cognition deficits in a PTSD rat model via the BDNF signaling pathway of the hippocampus and amygdala

BACKGROUND

Post-traumatic stress disorder (PTSD) is associated with traumatic stress experiences. This condition can be accompanied by learning and cognitive deficits. Studies have demonstrated that ketamine can rapidly and significantly alleviate symptoms in patients with chronic PTSD. Nonetheless, the effects of ketamine on neurocognitive impairment and its mechanism of action in PTSD remain unclear.

METHODS

In this study, different concentrations of ketamine (5, 10, 15, and 20 mg/kg, i.p.) were evaluated in rat models of single prolonged stress and electrophonic shock (SPS&S). Expression levels of brain-derived neurotrophic factor (BDNF) and post-synaptic density-95 (PSD-95) in the hippocampus (HIP) and amygdala (AMG) were determined by Western blot analysis and immunohistochemistry.

RESULTS

The data showed that rats subjected to SPS&S exhibited significant PTSD-like cognitive impairment. The effect of ketamine on SPS&S-induced neurocognitive function showed a U-shaped dose effect in rats. A single administration of ketamine at a dosage of 10-15 mg/kg resulted in significant changes in behavioral outcomes. These manifestations of improvement in cognitive function and molecular changes were reversed at high doses (15-20 mg/kg).

CONCLUSION

Overall, ketamine reversed SPS&S-induced fear and spatial memory impairment and the down-regulation of BDNF and BDNF-related PSD-95 signaling in the HIP and AMG. A dose equal to 15 mg/kg rapidly reversed the behavioral and molecular changes and promoted the amelioration of cognitive dysfunction. The enhanced association of BDNF signaling with PSD-95 effects could be involved in the therapeutic efficiency of ketamine for PTSD.

Prominent genetic variants and epigenetic changes in post-traumatic stress disorder among combat veterans

Post-traumatic stress disorder (PTSD) is one of the most widespread and disabling psychiatric disorders among combat veterans. Substantial interindividual variability in susceptibility to PTSD suggests the presence of different risk factors for this disorder. Twin and family studies confirm genetic factors as important risk factors for PTSD. In addition to genetic factors, epigenetic factors, especially DNA methylation, can be considered as a potential mechanism in changing the risk of PTSD. So far, many genetic and epigenetic association studies have been conducted in relation to PTSD. In genetic studies, many single nucleotide polymorphisms have been identified as PTSD risk factors. Meanwhile, the variations in catecholamines-related genes, serotonin transporter and receptors, brain-derived neurotrophic factor, inflammatory factors, and apolipoprotein E are the most prominent candidates. CpG methylation in the upstream regions of many genes is also considered a PTSD risk factor. Accurate identification of genetic and epigenetic changes associated with PTSD can lead to the presentation of suitable biomarkers for susceptible individuals to this disorder. This study aimed to delineate prominent genetic variations and epigenetic changes associated with post-traumatic stress disorder in military veterans who have experienced combat, focusing on genetic and epigenetic association studies.

Peripheral brain-derived neurotrophic factor (BDNF) in insomnia: A systematic review and meta-analysis

The brain-derived neurotrophic factor (BDNF) is associated with emotional and cognitive functioning, and it is considered a transdiagnostic biomarker for mental disorders. Literature on insomnia related BDNF changes yielded contrasting results and it has never been synthetized using meta-analysis. To fill this gap, we conducted a systematic review and meta-analysis of case-control studies examining the levels of peripheric BDNF in individuals with insomnia and healthy controls using the PRISMA guidelines. PubMed, Scopus, Medline, PsycINFO and CINAHL were searched up to Nov 2022. Nine studies met the inclusion criteria and were assessed using the Newcastle-Ottawa Scale. Eight studies reported sufficient data for meta-analysis. Random-effects models showed lower BDNF in subjects with insomnia (n = 446) than in controls (n = 706) (Hedge's g = -0.86, 95% CI: -1.39 to -0.32, p = .002). Leave-one-out sensitivity analysis confirmed that the pooled effect size was robust and not driven by any single study. However, given the small sample size, the cross-sectional nature of the measurement, and the high heterogeneity of included data, the results should be cautiously interpreted. Progress in the study of BDNF in insomnia is clinically relevant to better understand the mechanisms that may explain the relationship between disturbed sleep and mental disorders.

Intimate partner violence: psycho-physio-pathological sequelae for defining a holistic enriched treatment

Intimate partner violence (IPV) is a health priority, which worldwide, mainly affects women. The consequences of IPV include several psychophysiological effects. These range from altered levels of hormones and neurotrophins to difficulties in emotion regulation and cognitive impairment. Mounting evidence from preclinical studies has shown that environmental enrichment, a form of sensory-motor, cognitive, and social stimulation, can induce a wide range of neuroplastic processes in the brain which consistently improve recovery from a wide variety of somatic and psychiatric diseases. To support IPV survivors, it is essential to ensure a safe housing environment, which can serve as a foundation for environmental enrichment-based interventions. However, some concerns have been raised when supportive housing interventions focus on the economic aspects of survivors’ lives instead of the emotional ones. We thus propose a holistic intervention in which supportive housing is integrated with evidenced-based psychotherapies which could constitute an enriched therapeutic approach for IPV survivors.

Neurotrophic factors, childhood trauma and psychiatric disorders: A systematic review of genetic, biochemical, cognitive and imaging studies to identify potential biomarkers

BACKGROUND

Exposure to traumatic experience represents one of the key environmental factors influencing the risk for several psychiatric disorders, in particular when suffered during childhood, a critical period for brain development, characterized by a high level of neuroplasticity. Abnormalities affecting neurotrophic factors might play a fundamental role in the link between childhood trauma (CT) and early life stress (ELS) and psychiatric disorders.

METHODS

A systematic review was conducted, considering genetic, biochemical and expression studies along with cognitive and brain structure imaging investigations, based on PubMed and Web of Science databases (available up until November 2021), to identify potential neuroplasticity related biomarkers associated both with CT/ELS and psychiatric disorders. The search was followed by data abstraction and study quality assessment (Newcastle-Ottawa Scale).

RESULTS

103 studies met our eligibility criteria. Among them, 65 were available for genetic, 30 for biochemical and 3 for mRNA data; 45 findings were linked to specific symptomatology/pathologies, 16 with various cognitive functions, 19 with different brain areas, 6 on methylation and 36 performed on control subjects for the Brain Derived Neurotrophic Factor (BDNF); whereas 4 expression/biochemical studies covered Neurotrophin 4 (NT-4), Vascular Endothelium Growth Factor (VEGF), Epidermal Growth Factor (EGF), Fibroblast Growth Factor (FGF), and Transforming Growth Factor β1 (TGF-β1).

LIMITATIONS

Heterogeneity of assessments (biological, psychological, of symptomatology, and CT/ELS), age range and ethnicity of samples for BDNF studies; limited studies for other neurotrophins.

CONCLUSIONS

Results support the key role of BDNF (in form of Met allele) as biomarker, both at genetic and biochemical level, in mediating the effect of CT/ELS in psychiatric disorders, passing through specific cognitive functions and specific brain region architecture.

Symptom cluster profiles following traumatic orthopaedic injuries

BACKGROUND

Millions of Americans experience traumatic orthopaedic injuries (TOIs) annually. Post-injury symptoms of acute stress disorder (ASD), anxiety, depression, pain, and sleep disturbance are common. Symptoms often present in clusters. Symptom cluster profiles phenotypically characterize TOI survivors' experiences with clustered symptoms. Expression of brain-derived neurotrophic factor (BDNF) may contribute to the biological underpinnings of symptom cluster profile membership.

METHODS

We recruited hospitalized TOI survivors within 72 hours of injury. We measured symptoms of ASD with the Acute Stress Disorder Scale and symptoms of anxiety, depression, pain, and sleep disturbance with Patient-Reported Outcomes Measurement Information System (PROMIS) short forms. We measured serum BDNF concentrations with enzyme-linked immunosorbent assay (ELISA) and identified rs6265 genotypes with TaqMan real-time PCR. We performed latent profile analysis to identify the symptom cluster profiles. We identified the variables associated with symptom cluster profile membership with unadjusted and adjusted multinomial logistic regression.

RESULTS

We identified 4 symptom cluster profiles characterized by symptom severity that we labelled Physical Symptoms Only, and Mild, Moderate, and Severe Psychological Distress. Age, self-identified Black race, resilience, and serum BDNF concentrations were associated with lower odds, and female sex with higher odds, of being in the Psychological Distress clusters. Clinical characteristics and rs6265 genotypes were not associated with symptom cluster profile membership.

CONCLUSION

TOI survivors experience distinct symptom cluster profiles. Sociodemographic characteristics and serum BDNF concentrations, not clinical characteristics, were associated with symptom cluster profile membership. These findings support comprehensive symptom screening and treatment for all TOI survivors and further evaluating BDNF as a biomarker of post-injury symptom burden.

Molecular actions of sex hormones in the brain and their potential treatment use in anxiety disorders

Anxiety disorders are one of the most prevalent mood disorders that can lead to impaired quality of life. Current treatment of anxiety disorders has various adverse effects, safety concerns, or restricted efficacy; therefore, novel therapeutic targets need to be studied. Sex steroid hormones (SSHs) play a crucial role in the formation of brain structures, including regions of the limbic system and prefrontal cortex during perinatal development. In the brain, SSHs have activational and organizational effects mediated by either intracellular or transmembrane G-protein coupled receptors. During perinatal developmental periods, the physiological concentrations of SSHs lead to the normal development of the brain; however, the early hormonal dysregulation could result in various anxiety diorders later in life. Sex differences in the prevalence of anxiety disorders suggest that SSHs might be implicated in their development. In this review, we discuss preclinical and clinical studies regarding the role of dysregulated SSHs signaling during early brain development that modifies the risk for anxiety disorders in a sex-specific manner in adulthood. Moreover, our aim is to summarize potential molecular mechanisms by which the SSHs may affect anxiety disorders in preclinical research. Finally, the potential effects of SSHs in the treatment of anxiety disorders are discussed.

PTSD as an Endothelial Disease: Insights From COVID-19

SARS-CoV-2 virus, the etiologic agent of COVID-19, has affected almost every aspect of human life, precipitating stress-related pathology in vulnerable individuals. As the prevalence rate of posttraumatic stress disorder in pandemic survivors exceeds that of the general and special populations, the virus may predispose to this disorder by directly interfering with the stress-processing pathways. The SARS-CoV-2 interactome has identified several antigens that may disrupt the blood-brain-barrier by inducing premature senescence in many cell types, including the cerebral endothelial cells. This enables the stress molecules, including angiotensin II, endothelin-1 and plasminogen activator inhibitor 1, to aberrantly activate the amygdala, hippocampus, and medial prefrontal cortex, increasing the vulnerability to stress related disorders. This is supported by observing the beneficial effects of angiotensin receptor blockers and angiotensin converting enzyme inhibitors in both posttraumatic stress disorder and SARS-CoV-2 critical illness. In this narrative review, we take a closer look at the virus-host dialog and its impact on the renin-angiotensin system, mitochondrial fitness, and brain-derived neurotrophic factor. We discuss the role of furin cleaving site, the fibrinolytic system, and Sigma-1 receptor in the pathogenesis of psychological trauma. In other words, learning from the virus, clarify the molecular underpinnings of stress related disorders, and design better therapies for these conditions. In this context, we emphasize new potential treatments, including furin and bromodomains inhibitors.

The Influence of Psychotherapy on Peripheral Brain-Derived Neurotrophic Factor Concentration Levels and Gene Methylation Status: A Systematic Review

Psychotherapy is a well-established method of treating many mental disorders. It has been proven that psychotherapy leads to structural and functional changes in the brain; however, knowledge about the molecular and cellular mechanisms of these changes is limited. Neuroplasticity and one of its mediators, brain-derived neurotrophic factor (BDNF), are potential research targets in this field. To define the role of BDNF concentration in serum, or in plasma, and BDNF promoter gene methylation in saliva or leucocytes, in psychotherapy, an extensive literature search was conducted in the PubMed and Web of Science databases. The literature review was conducted based on papers published up until May 2021 that included pre and post psychotherapy measurements of either BDNF concentration levels or promoter gene methylation status. Ten studies were indicated as eligible for analysis: eight studies that investigated peripheral BDNF concentration levels, one study that investigated methylation status, and one study that included an evaluation of both subject matters. Patients underwent cognitive behavioral therapy or interpersonal psychotherapy. Patients were diagnosed with borderline personality disorder, major depressive disorder, anorexia nervosa, bulimia nervosa, or post-traumatic stress disorder. There were only three of the nine studies that showed statistically significant increases in BDNF concentration levels after psychotherapy. The two studies that involved BDNF gene methylation status showed a decrease in methylation after dialectical behavioral therapy of borderline patients.

Serum brain-derived neurotrophic factor remains elevated after long term follow-up of combat veterans with chronic post-traumatic stress disorder

Attempts to correlate blood levels of brain-derived neurotrophic factor (BDNF) with post-traumatic stress disorder (PTSD) have provided conflicting results. Some studies found a positive association between BDNF and PTSD diagnosis and symptom severity, while others found the association to be negative. The present study investigated whether serum levels of BDNF are different cross-sectionally between combat trauma-exposed veterans with and without PTSD, as well as whether longitudinal changes in serum BDNF differ as a function of PTSD diagnosis over time. We analyzed data of 270 combat trauma-exposed veterans (230 males, 40 females, average age: 33.29 ± 8.28 years) and found that, at the initial cross-sectional assessment (T0), which averaged 6 years after the initial exposure to combat trauma (SD=2.83 years), the PTSD positive group had significantly higher serum BDNF levels than the PTSD negative controls [31.03 vs. 26.95 ng/mL, t(268) = 3.921, p < 0.001]. This difference remained significant after excluding individuals with comorbid major depressive disorder, antidepressant users and controlling for age, gender, race, BMI, and time since trauma. Fifty-nine of the male veterans who participated at the first timepoint (T0) were re-assessed at follow-up evaluation (T1), approximately 3 years (SD=0.88 years) after T0. A one-way ANOVA comparing PTSD positive, "subthreshold PTSD" and control groups revealed that serum BDNF remained significantly higher in the PTSD positive group than the control group at T1 [30.05 vs 24.66 ng/mL, F(2, 56)= 3.420, p = 0.040]. Serum BDNF levels did not correlate with PTSD symptom severity at either time point within the PTSD group [r(128) = 0.062, p = 0.481 and r(28) = 0.157, p = 0.407]. Serum BDNF did not significantly change over time within subjects [t(56) = 1.269, p = 0.210] nor did the change of serum BDNF from T0 to T1 correlate with change in PTSD symptom severity within those who were diagnosed with PTSD at T0 [r(27) = -0.250, p = 0.192]. Our longitudinal data are the first to be reported in combat PTSD and suggest that higher serum BDNF levels may be a stable biological characteristic of chronic combat PTSD independent of symptom severity.

Retracing our steps to understand ketamine in depression: A focused review of hypothesized mechanisms of action

Introduction

MDD represents a significant burden worldwide, and while a number of approved treatments exist, there are high rates of treatment resistance and refractoriness. Ketamine, an N-methyl-d-aspartate receptor (NMDAR) antagonist, is a novel, rapid-acting antidepressant, however the mechanisms underlying the efficacy of ketamine are not well understood and many other mechanisms outside of NMDAR antagonism have been postulated based on preclinical data. This focused review aims to present a summary of the proposed mechanisms of action by which ketamine functions in depressive disorders supported by preclinical data and clinical studies in humans.

Methods

A literature search was completed using the PubMed and Google Scholar databases. Results were limited to clinical trials and case studies in humans that were published in English. The findings were used to compile this article.

Results

The antidepressant effects associated with ketamine are mediated via a complex interplay of mechanisms; key steps include NMDAR blockade on γ-aminobutyric acid interneurons, glutamate surge, and subsequent activation and upregulation of α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptor.

Discussion

Coadministration of ketamine for MDD with other psychotropic agents, for example benzodiazepines, may attenuate antidepressant effects. Limited evidence exists for these effects and should be evaluated on a case-by-case basis.

Translational relevance of fear conditioning in rodent models of mild traumatic brain injury

Mild traumatic brain injury (mTBI) increases the risk of posttraumatic stress disorder (PTSD) in military populations. Utilizing translationally relevant animal models is imperative for establishing a platform to delineate neurobehavioral deficits common to clinical PTSD that emerge in the months to years following mTBI. Such platforms are required to facilitate preclinical development of novel therapeutics. First, this mini review provides an overview of the incidence of PTSD following mTBI in military service members. Secondly, the translational relevance of fear conditioning paradigms used in conjunction with mTBI in preclinical studies is evaluated. Next, this review addresses an important gap in the current preclinical literature; while incubation of fear has been studied in other areas of research, there are relatively few studies pertaining to the enhancement of cued and contextual fear memory over time following mTBI. Incubation of fear paradigms in conjunction with mTBI are proposed as a novel behavioral approach to advance this critical area of research. Lastly, this review discusses potential neurobiological substrates implicated in altered fear memory post mTBI.

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.

Moderating Effects of BDNF Genetic Variants and Smoking on Cognition in PTSD Veterans

Posttraumatic stress disorder (PTSD) is frequently associated with cognitive disturbances and high prevalence of smoking. This study evaluated cognition in war veterans with PTSD and control subjects, controlled for the effect of smoking and brain derived neurotrophic factor (BDNF) rs6265 and rs56164415 genotypes/alleles. Study included 643 male war veterans with combat related PTSD and 120 healthy controls. Genotyping was done by real time PCR. Cognitive disturbances were evaluated using the Positive and Negative Syndrome Scale (PANSS) cognition subscale and the Rey-Osterrieth Complex Figure (ROCF) test scores. Diagnosis (p < 0.001), BDNF rs56164415 (p = 0.011) and smoking (p = 0.028) were significant predictors of the cognitive decline in subjects with PTSD. BDNF rs56164415 T alleles were more frequently found in subjects with PTSD, smokers and non-smokers, with impaired cognition, i.e., with the higher PANSS cognition subscale scores and with the lower ROCF immediate recall test scores. Presence of one or two BDNF rs56164415 T alleles was related to cognitive decline in PTSD. The T allele carriers with PTSD had advanced cognitive deterioration in smokers and nonsmokers with PTSD, and worse short-term visual memory function. Our findings emphasize the role of the BDNF rs56164415 T allele and smoking in cognitive dysfunction in war veterans with PTSD.

Neurosteroids and Neurotrophic Factors: What Is Their Promise as Biomarkers for Major Depression and PTSD?

Even though major depressive disorder (MDD) and post-traumatic stress disorder (PTSD) are among the most prevalent and incapacitating mental illnesses in the world, their diagnosis still relies solely on the characterization of subjective symptoms (many of which are shared by multiple disorders) self-reported by patients. Thus, the need for objective measures that aid in the detection of and differentiation between psychiatric disorders becomes urgent. In this paper, we explore the potential of neurosteroids and neurotrophic proteins as biomarkers for MDD and PTSD. Circulating levels of the GABAergic neuroactive steroid, allopregnanolone, are diminished in MDD and PTSD patients, which corroborates the finding of depleted neurosteroid levels observed in animal models of these disorders. The neurotrophic protein, brain-derived neurotropic factor (BDNF), is also reduced in the periphery and in the brain of MDD patients and depressed-like animals that express lower neurosteroid levels. Although the role of BDNF in PTSD psychopathology seems less clear and merits more research, we propose a causal link between allopregnanolone levels and BDNF expression that could function as a biomarker axis for the diagnosis of both MDD and PTSD.

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-HT2A and 5-HT1A 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.

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.

Reduced serum BDNF levels are associated with the increased risk for developing MDD: a case-control study with or without antidepressant therapy

Objective

We do not have any consistent markers for major depressive disorder (MDD) though various biological factors are involved in the pathophysiology. We aimed to evaluate the serum brain-derived neurotrophic factor (BDNF) levels in MDD patients with or without antidepressant therapy compared to healthy controls (HCs).

Results

We assessed serum BDNF levels among three groups: drug-naïve MDD patients (n = 41), drug-treated MDD patients (n = 44), and age-and sex-matched HCs (n = 82). Serum BDNF levels were measured by enzyme-linked immunosorbent assay (ELISA) kit. Serum levels of BDNF were detected significantly lower in drug-naïve MDD patients compared to HCs. No significant alterations of serum BDNF levels between drug-treated patients and HCs were identified. Significant negative correlations between serum BDNF levels and Hamilton depression rating (Ham-D) scores were observed in both drug-naïve and drug-treated MDD patients. Receiver operating characteristic (ROC) analysis showed good diagnostic value for serum BDNF levels in drug-naïve MDD patients with the area under the curve at 0.821. The present study suggests that low serum BDNF levels may be involved in the pathophysiology of MDD. The reduced serum BDNF levels might be used as an early risk assessment marker for major depression.

A longitudinal study of the associations of BDNF genotype and methylation with poststroke anxiety

BACKGROUND

Although the precise etiology of poststroke anxiety (PSA) has yet to be fully elucidated, it is known that brain-derived neurotrophic factor (BDNF) is important for neural plasticity and long-term potentiation, associated with the pathophysiology of anxiety. The expression of BDNF is regulated by epigenetic and genetic profiles. Thus, we investigated the association between BDNF methylation status and PSA at 2 weeks and 1 year after stroke while accounting for interactions with the BDNF Val66Met polymorphism.

METHODS

The baseline sample comprised 286 patients who were assessed at 2 weeks after stroke; of these patients, 222 (78%) were followed up with at 1 year after stroke. The presence of PSA was determined using the anxiety subscale of the Hospital Anxiety and Depression Scale (HADS), and the effects of BDNF methylation status and polymorphisms on PSA status were assessed with multivariate logistic regression models.

RESULTS

The prevalence of PSA was slightly lower (27 [9.4%]) at baseline, and 35 (15.8%) patients were identified as having PSA at the 1-year follow-up. Stroke patients with a higher average methylation status were more likely to have PSA at 1 year. The BDNF Val66Met polymorphism was not independently associated with PSA during either the acute or chronic phase after stroke, but there was a significant interactive effect between BDNF methylation and genotype on PSA at 2 weeks.

CONCLUSIONS

In this study, BDNF methylation in combination with the met/met BDNF polymorphism (Val66Met polymorphism) was associated with PSA. These findings may help identify patients at higher risk for PSA.

The mediating effect of trauma and stressor related symptoms and ruminations on the relationship between autistic traits and mood spectrum

An increasing number of studies highlighted significant correlations between autistic traits (AT) and mood spectrum symptoms. Moreover, recent data showed that individuals with high AT are likely to develop trauma and stressor-related disorders. This study aims to investigate the relationship between AT and mood symptoms among university students, focusing in particular on how AT interact with ruminations and trauma-related symptomatology in predicting mood symptoms. 178 students from three Italian Universities of excellence were assessed with The Structured Clinical Interview for DSM-5 (SCID-5), the Adult Autism Subthreshold Spectrum (AdAS Spectrum), the Ruminative Response Scale (RRS), the Trauma and Loss Spectrum (TALS) and the Moods Spectrum (MOODS). Considering the AdAS Spectrum total scores, 133 subjects (74.7%) were categorized as "low scorers" and 45 subjects (25.3%) as "high scorers". Students in the high scorer group showed significantly higher scores on RRS, TALS-SR and MOOD-SR total scores. Total and direct effects of AdAS Spectrum total score on MOODS-SR total score were both statistically significant. AdAS Spectrum total score also showed a significant indirect effect on MOODS-SR total score through TALS and RRS total scores. Results showed a significant relationship between AT and mood spectrum, which is partially mediated by ruminations and trauma/stressor-related symptomatology.

Post Traumatic Stress Disorder Heralding the Onset of Semantic Frontotemporal Dementia

Background:

Post traumatic stress disorder (PTSD) is associated with cognitive decline. The dementia type following PTSD is unclear.

Objective:

To assess whether PTSD is associated with a specific dementia.

Methods:

Prospective study: 46 PTSD patients (DSM-IV-TR) were followed for 6–10 years with clinical, neuropsychological, imaging evaluations for possible development of dementia.

Retrospective study:

849 dementia patients followed during 1999–2014 (509 Alzheimer’s disease, AD; 207 dementia with Lewy bodies, DLB; 90 vascular dementia, VaD; 43 frontotemporal dementia, FTD) and 287 patients with any neurological condition (including patients with/without dementia) were evaluated for the presence of PTSD in their history.

Results:

Prospective study: 8 patients developed dementia; 1 AD, 1 DLB, 6 semantic FTD (13.0% of the PTSD population). Retrospective study: 38 patients (4.5%) had a history of PTSD; 3.5% of AD, 4.3% of DLB, 14.0% of FTD, 5.6% of VaD. The percentage was higher in FTD than in AD or DLB (χ² = 10, p = 0.001, and χ² = 6, p = 0.02). At difference with AD, DLB, or VaD, FTD incidence among dementia patients with PTSD history (38 patients) was higher than in the dementia population overall (16% versus 5%, χ² = 8, p = 0.005). The impact of possible demographical/clinical confounders (age, gender, MMSE) was excluded by Poisson regression. PTSD prevalence in the comparative group without dementia matched the prevalence in the Italian general population (1.1%). PTSD prevalence in the demented comparative group matched the prevalence in our dementia retrospective cohort, 3.7%).

Discussion:

PTSD was associated with the development of semantic FTD.

Evaluation of BDNF levels in patients hospitalized for physical trauma at an emergency hospital in Porto Alegre, southern Brazil

OBJECTIVE

To assess the association between brain-derived neurotrophic factor (BDNF) levels and acute stress disorder (ASD) in patients who have suffered physical trauma.

METHODS

Data were collected at an emergency hospital in Porto Alegre, state of Rio Grande do Sul, southern Brazil. Participants were over 18 years of age, victims of physical trauma, and had been hospitalized for a minimum of 48 hours. A total of 117 hospitalized patients who agreed to participate in the research were grouped according to the shift in which blood was collected (38 subjects from the morning shift and 79 from the afternoon shift), had their BDNF levels measured and responded to other questionnaires. Respondents were further grouped by age into three ranges: 18-30, 31-50 and 51-70 years.

RESULTS

We found a significant difference in the distribution of BDNF between the two shifts in which blood samples were collected, with the afternoon group having higher BDNF levels (U = 1906.5, p = 0.018). A difference was observed only between the 18-30 group and the 51-70 group in the afternoon shift (Umorning = 1107, pmorning = 0.575; Uafternoon = 7175, pafternoon = 0.028).

CONCLUSIONS

The population whose blood samples were collected in the afternoon showed significantly higher values of BDNF compared to those of the morning shift. This same population presented lower BDNF levels when associated with ASD subtypes A1, A2, and A. We hypothesize that the lower values of BDNF measured in the morning shift were due to a response to the circadian cycle of cortisol, whose action inhibits the expression of serum neurotrophins.

Fear of cancer recurrence among breast cancer survivors could be controlled by prudent dietary modification with polyunsaturated fatty acids

BACKGROUND

The pathophysiology of fear of cancer recurrence (FCR), the leading unmet psychological need of cancer survivors, may involve the dysfunctional processing of fear memory. n-3 polyunsaturated fatty acids (PUFAs) have beneficial effects on psychiatric disorders, including depressive disorder and anxiety disorders, and are involved in fear memory processing. We hypothesized that n-3 PUFA composition is associated with FCR in cancer survivors.

METHODS

We conducted a cross-sectional study to examine the relationship between n-3 PUFAs and FCR among breast cancer survivors. Adults who had been diagnosed with invasive breast cancer and were not undergoing chemotherapy were asked to participate. Blood PUFA composition was evaluated by using capillary blood. We directly administered the Concerns About Recurrence Scale (CARS) to assess the grade of FCR.

RESULTS

Among 126 participants used for the analysis, the mean age (SD) was 58 (11) years and 47% had stage I cancer. Multiple regression analysis controlling for possible confounders, depressive symptoms, and post-traumatic stress disorder (PTSD) symptoms revealed that the alpha-linolenic acid (ALA) level was significantly inversely associated with the average score on the CARS overall fear index (beta = -0.165, p = 0.04). No significant associations were found for other PUFAs.

LIMITATIONS

Our findings were obtained from a cross-sectional study in a single institute.

CONCLUSION

These findings provide the first evidence of a beneficial effect of ALA on FCR and indicate the need for prospective study of this association. FCR among breast cancer survivors might be controllable by prudent selection of ALA-containing cooking oil.

Neuroinflammation and cognition across psychiatric conditions

Cognitive impairments reported across psychiatric conditions (ie, major depressive disorder, bipolar disorder, schizophrenia, and posttraumatic stress disorder) strongly impair the quality of life of patients and the recovery of those conditions. There is therefore a great need for consideration for cognitive dysfunction in the management of psychiatric disorders. The redundant pattern of cognitive impairments across such conditions suggests possible shared mechanisms potentially leading to their development. Here, we review for the first time the possible role of inflammation in cognitive dysfunctions across psychiatric disorders. Raised inflammatory processes (microglia activation and elevated cytokine levels) across diagnoses could therefore disrupt neurobiological mechanisms regulating cognition, including Hebbian and homeostatic plasticity, neurogenesis, neurotrophic factor, the HPA axis, and the kynurenine pathway. This redundant association between elevated inflammation and cognitive alterations across psychiatric disorders hence suggests that a cross-disorder approach using pharmacological and nonpharmacological (ie, physical activity and nutrition) anti-inflammatory/immunomodulatory strategies should be considered in the management of cognition in psychiatry.

Correlates of neurocognitive functions in individuals at ultra-high risk for psychosis - A 6-month follow-up study

Cognitive deficits are evident at the prodromal phase of psychosis. It has been noted that brain-derived neurotrophic factor (BDNF) is correlated with cognition in both preclinical and clinical studies. However, to our knowledge, no study has evaluated blood BDNF levels and their association with cognitive impairment in individuals at ultra-high risk for psychosis (UHR). We included 13 individuals at UHR and 30 healthy controls (HC) matched by sex, age, and educational level. Plasma BDNF levels were measured at baseline and 6 months. Neurocognitive functions (executive functions, speed of processing, verbal learning and memory, working memory) were examined at 6 months. Regression analyses were conducted to examine the relationship between BDNF levels and cognitive performance. BDNF levels were lower in UHR group than in HC group both at baseline and at 6 months (P = 0.001, and P = 0.007, respectively). There were no associations between plasma BDNF levels and all of the cognitive domains in both groups. Our findings showed that peripheral BDNF levels were not related to cognitive deficits in UHR and HC groups while the lower BDNF level in the former persisted up to 6 months. Further research is needed in a large sample.

Altered levels of brain-derived neurotrophic factor, proBDNF and tissue plasminogen activator in children with posttraumatic stress disorder

The current study aims to compare the serum brain-derived neurotrophic factor (BDNF), proBDNF and tissue plasminogen activator (tPA) levels in cases that have developed posttraumatic stress disorder (PTSD) in consequence of sexual abuse with those in healthy control subjects. Thirty-one female patients between 8 and 18 years of age who have been diagnosed with PTSD due to sexual abuse and thirty-one healthy female volunteer controls were included in the study. Frequency, intensity and severity of PTSD symptoms were assessed on the basis of Clinician-Administered Post-Traumatic Stress Disorder Scale for Children and Adolescents (CAPS-CA). Serum BDNF, proBDNF and tPA levels were measured by Enzyme-Linked Immunosorbent Assay (ELISA) method. Results of the present study revealed that serum levels of BDNF and proBDNF in PTSD group were significantly lower but tPA level was significantly higher as compared to healthy control subjects. There were no correlations between CAPS-CA scores and BDNF, proBDNF and tPA levels. Decreased levels of BDNF, as suggested to have a role in the etiopathogenesis of PTSD, appear to be a result of the reduction in proBDNF production. The increased tPA levels in such cases, on the other hand, can be a compensatory mechanism serving to increase the BDNF levels.

Chronic Hippocampal Abnormalities and Blunted HPA Axis in an Animal Model of Repeated Unpredictable Stress

Incidence of post-traumatic stress disorder (PTSD) ranges from 3 to 30% in individuals exposed to traumatic events, with the highest prevalence in groups exposed to combat, torture, or rape. To date, only a few FDA approved drugs are available to treat PTSD, which only offer symptomatic relief and variable efficacy. There is, therefore, an urgent need to explore new concepts regarding the biological responses causing PTSD. Animal models are an appropriate platform for conducting such studies. Herein, we examined the chronic behavioral and neurobiological effects of repeated unpredictable stress (RUS) in a mouse model. 12 weeks-old C57BL/6J male mice were exposed to a 21-day RUS paradigm consisting of exposures to a predator odor (TMT) whilst under restraint, unstable social housing, inescapable footshocks and social isolation. Validity of the model was assessed by comprehensive examination of behavioral outcomes at an acute timepoint, 3 and 6 months post-RUS; and molecular profiling was also conducted on brain and plasma samples at the acute and 6 months timepoints. Stressed mice demonstrated recall of traumatic memories, passive stress coping behavior, acute anxiety, and weight gain deficits when compared to control mice. Immunoblotting of amygdala lysates showed a dysregulation in the p75NTR/ProBDNF, and glutamatergic signaling in stressed mice at the acute timepoint. At 6 months after RUS, stressed mice had lower plasma corticosterone, reduced hippocampal CA1 volume and reduced brain-derived neurotrophic factor levels. In addition, glucocorticoid regulatory protein FKBP5 was downregulated in the hypothalamus of stressed mice at the same timepoint, together implicating an impaired hypothalamus-pituitary-adrenal-axis. Our model demonstrates chronic behavioral and neurobiological outcomes consistent with those reported in human PTSD cases and thus presents a platform through which to understand the neurobiology of stress and explore new therapeutic interventions.

Neurotrophic factors and hippocampal activity in PTSD

Although numerous studies have investigated the neurotrophic factors and hippocampal activity in posttraumatic stress disorder (PTSD) separately each other, it is unclear whether an association between neurotrophic factors and hippocampal activity is present. The aim of this study was to evaluate the functional changes in hippocampus before and after treatment with escitalopram and to associate these changes with peptides related to neuronal growth in patients with chronic PTSD and trauma survivors without PTSD. Fifteen earthquake survivors with chronic PTSD and thirteen drug naïve trauma exposed individuals without PTSD underwent fMRI scans in a block design. Serum levels of Nerve Growth Factor (NGF) and Brain Derived Neurotrophic Factor (BDNF) were measured before and after 12 weeks treatment with escitalopram. Baseline median serum level of NGF was significantly lower in patients with chronic PTSD than trauma survivors; however, 12 weeks of treatment with escitalopram significantly increased it. Higher activation was found both in left and right hippocampus for chronic PTSD group than trauma survivors. Treatment with escitalopram was significantly associated with suppression of the hyperactivation in left hippocampus in patients with chronic PTSD. Bilateral hyperactivation in hippocampus and lowered NGF may associate with neurobiological disarrangements in chronic PTSD. Treatment with escitalopram was significantly associated with both improvement in the severity of PTSD symptoms and biological alterations. Patients diagnosed with PTSD may have further and complicated deteriorations in hippocampal networks and neurotransmitter systems than individuals who had not been diagnosed with PTSD following the same traumatic experience.

Serum brain-derived neurotrophic factor in children with coeliac disease

BACKGROUND

Brain-derived neurotrophic factor (BDNF) is a neurotrophin that has a protective role in the nervous system and is involved in neural plasticity. It is abundant in the central nervous system, but is also expressed in the gastrointestinal tract. Coeliac disease (CD), characterised by intestinal inflammation, has some comorbidity with neurologic and mental disorders. The aim of this study was to evaluate circulating BDNF concentrations in patients with CD at diagnosis or on a gluten-free diet (GFD) for longer than 1 year and in healthy controls (HC).

MATERIALS AND METHODS

Fifty newly diagnosed patients with CD (aged 8.6 ± 3.7 years, 64.0% females), thirty-nine patients on GFD for longer than 1 year (aged 10.4 ± 3.4 years, 71.8% females) and 36 HC (aged 8 ± 1.7 years, 33.3% females) were included in the study. Along with anthropometric evaluation and standard blood chemistry, serum BDNF levels were measured by a specific immunoenzymatic assay.

RESULTS

Patients at diagnosis and on GFD had significantly higher BDNF levels (26 110 ± 8204 and 28 860 ± 7992 pg/mL), respectively, than HC (19 630 ± 8093 pg/mL, P < .001 for both CD groups). Patients on GFD had significantly higher BDNF levels than those at diagnosis (P = .02).

CONCLUSIONS

Serum BDNF concentrations were higher in patients with CD than in HC, regardless of their status of gluten consumption. This could be attributed either to a potential protective response to the inflammation of the intestine or to chronic stress.

Mechanisms underlying the effects of n-3 polyunsaturated fatty acids on fear memory processing and their hypothetical effects on fear of cancer recurrence in cancer survivors

The relationship of n-3 polyunsaturated fatty acids (PUFAs) and gut microbiota with brain function has been extensively reported. Here, we review how n-3 polyunsaturated fatty acids affect fear memory processing. n-3 PUFAs may improve dysfunctional fear memory processing via immunomodulation/anti-inflammation, increased BDNF, upregulated adult neurogenesis, modulated signal transduction, and microbiota-gut-brain axis normalization. We emphasize how n-3 PUFAs affect this axis and also focus on the hypothetical effects of PUFAs in fear of cancer recurrence (FCR), the primary psychological unmet need of cancer survivors. Its pathophysiology may be similar to that of post-traumatic stress disorder (PTSD), which involves dysfunctional fear memory processing. Due to fewer adverse effects than psychotropic drugs, nutritional interventions involving n-3 PUFAs should be acceptable for physically vulnerable cancer survivors. We are currently studying the relationship of FCR with n-3 PUFAs and gut microbiota in cancer survivors to provide them with a nutritional intervention that protects against FCR.

Peripheral levels of BDNF and opiate-use disorder: literature review and update

Several neurobiological factors are related to opiate-use disorder (OUD), and among them, neurotrophins have a relevant role. Brain-derived neurotrophic factor (BDNF) is a central neurotrophin involved in many neuronal processes, and it has been related to several psychiatric diseases and addictive disorders. BDNF can be measured in plasma and serum; its levels may reflect BDNF concentrations in the central nervous system (CNS) and, indirectly, CNS processes. Hence, peripheral BDNF could be a biomarker in clinical practice. This manuscript explores the findings about peripheral BDNF and OUD in humans. Opiates induce neurotoxicity in the CNS, which may be correlated with modifications in BDNF expression. Thus, basal levels of peripheral BDNF in OUD patients may be altered, which could be modified with abstinence. Also, opiates may modify epigenetic processes that may be associated with peripheral concentrations of BDNF, and in this line, withdrawal could reflect recovering processes in the CNS. Additionally, treatment modifies the peripheral concentrations of BDNF, but the clinical implications of those changes are yet not elucidated. No specific conclusion can be performed and more investigation in this area is necessary to elucidate the real potential of peripheral BDNF as a biomarker.

DBS in Treatment of Post-Traumatic Stress Disorder

Post-traumatic stress disorder (PTSD) is a debilitating psychiatric condition for which pharmacological therapy is not always solvable. Various treatments have been suggested and deep brain stimulation (DBS) is currently under investigation for patients affected by PTSD. We review the neurocircuitry and up-to-date clinical concepts which are behind the use of DBS in posttraumatic stress disorder (PTSD). The role of DBS in treatment-refractory PTSD patients has been investigated relying on both preclinical and clinical studies. DBS for PTSD is in its preliminary phases and likely to provide hope for patients with medical refractory PTSD following the results of randomized controlled studies.

No gene-by-environment interaction of BDNF Val66Met polymorphism and childhood maltreatment on anxiety sensitivity in a mixed race adolescent sample

Background: Anxiety disorders in youth are attributable to multiple causal mechanisms, comprising biological vulnerabilities, such as genetics and temperament, and unfavourable environmental influences, such as childhood maltreatment (CM). Objective: A gene-environment (G x E) interaction study was conducted to determine the interactive effect of the BDNF Val66Met polymorphism and CM to increase susceptibility to anxiety sensitivity (AS) in a sample of mixed race adolescents. Method: Participants (n = 308, mean age = 15.8 years) who were all secondary school students and who completed measures for AS and CM were genotyped for the BDNF Val66Met polymorphism. Hierarchical multiple regression analysis was conducted to assess G x E influences on AS. Age and gender were included in the models as covariates as age was significantly associated with AS total score (p < .05), and females had significantly higher AS scores than males (p < .05). Results: A main effect of CM on AS was evident (p < .05), however, no main effect of BDNF genotype on AS was observed (p > .05). A non-significant G x E effect on AS was revealed (p < .05). Conclusions: Our results suggest that CM does not have a moderating role in the relationship between the BDNF Val66Met genotype and the increased risk of anxiety-related phenotypes, such as AS. Given the exploratory nature of this study, findings require replication in larger samples and adjustment for population stratification to further explore the role of BDNF Val66Met and CM on AS in mixed race adolescents.

Synaptic Loss and the Pathophysiology of PTSD: Implications for Ketamine as a Prototype Novel Therapeutic

PURPOSE OF REVIEW

Studies of the neurobiology and treatment of PTSD have highlighted many aspects of the pathophysiology of this disorder that might be relevant to treatment. The purpose of this review is to highlight the potential clinical importance of an often-neglected consequence of stress models in animals that may be relevant to PTSD: the stress-related loss of synaptic connectivity.

RECENT FINDINGS

Here, we will briefly review evidence that PTSD might be a "synaptic disconnection syndrome" and highlight the importance of this perspective for the emerging therapeutic application of ketamine as a potential rapid-acting treatment for this disorder that may work, in part, by restoring synaptic connectivity. Synaptic disconnection may contribute to the profile of PTSD symptoms that may be targeted by novel pharmacotherapeutics.

Resilience and cross-network connectivity: A neural model for post-trauma survival

Literature on the neurobiological bases of Post-Traumatic Stress Disorder (PTSD) considers medial Prefrontal cortex (mPFC), a core region of the Default Mode Network (DMN), as a region involved in response regulation to stressors. Disrupted functioning of the DMN has been recognized at the basis of the pathophysiology of a number of mental disorders. Furthermore, in the evaluation of the protective factors to trauma consequence, an important role has been assigned to resilience. Our aim was to investigate the specific relation of resilience and PTSD symptoms severity with resting state brain connectivity in a traumatized population using magnetoencephalography (MEG), a non-invasive imaging technique with high temporal resolution and documented advantages in clinical applications. Nineteen Trauma Exposed non-PTSD (TENP) and 19 PTSD patients participated to a resting state MEG session. MEG functional connectivity of mPFC seed to the whole brain was calculated. Correlation between mPFC functional connectivity and Clinician Administered PTSD Scale (CAPS) or Connor-Davidson Resilience Scale (CD-RISC) total score was also assessed. In the whole group, it has been evidenced that the higher was the resilience, the lower was the cross-network connectivity between DMN and Salience Network (SN) nodes. Contrarily, in the TENP group, the negative correlation between resilience and DMN-SN cross-interaction disappeared, suggesting a protective role of resilience for brain functioning. Regarding our findings as a continuum between healthy and pathological after trauma outcomes, we could suggest a link between resilience and the good dialogue between the networks needed to face a traumatic event and its long-term consequence on individuals' lives.

Posttraumatic Stress Disorder: Perspectives for the Use of Deep Brain Stimulation

OBJECTIVES

Deep Brain Stimulation (DBS) has been either approved or is currently under investigation for a number of psychiatric disorders.

MATERIALS AND METHODS

We review clinical and preclinical concepts as well as the neurocircuitry that may be of relevance for the implementation of DBS in posttraumatic stress disorder (PTSD).

RESULTS

PTSD is a chronic and debilitating illness associated with dysfunction in well-established neural circuits, including the amygdala and prefrontal cortex. Although most patients often improve with medications and/or psychotherapy, approximately 20-30% are considered to be refractory to conventional treatments. In other psychiatric disorders, DBS has been investigated in treatment-refractory patients. To date, preclinical work suggests that stimulation at high frequency delivered at particular timeframes to different targets, including the amygdala, ventral striatum, hippocampus, and prefrontal cortex may improve fear extinction and anxiety-like behavior in rodents. In the only clinical report published so far, a patient implanted with electrodes in the amygdala has shown striking improvements in PTSD symptoms.

CONCLUSIONS

Neuroimaging, preclinical, and preliminary clinical data suggest that the use of DBS for the treatment of PTSD may be practical but the field requires further investigation.

Serum brain-derived neurotrophic factor (BDNF) concentrations in pregnant women with post-traumatic stress disorder and comorbid depression

There is accumulating evidence for the role of brain-derived neurotrophic factor (BDNF) in the pathophysiology of depression. However, the role of BDNF in the pathophysiology of post-traumatic stress disorder (PTSD) remains controversial, and no study has assessed BDNF concentrations among pregnant women with PTSD. We examined early-pregnancy BDNF concentrations among women with PTSD with and without depression. A total of 2928 women attending prenatal care clinics in Lima, Peru, were recruited. Antepartum PTSD and depression were evaluated using PTSD Checklist-Civilian Version (PCL-C) and Patient Health Questionnaire-9 (PHQ-9) scales, respectively. BDNF concentrations were measured in a subset of the cohort (N = 944) using a competitive enzyme-linked immunosorbent assay (ELISA). Logistic regression procedures were used to estimate odds ratios (OR) and 95 % confidence intervals (95 % CI). Antepartum PTSD (37.4 %) and depression (27.6 %) were prevalent in this cohort of low-income pregnant Peruvian women. Approximately 19.9 % of participants had comorbid PTSD-depression. Median serum BDNF concentrations were lower among women with comorbid PTSD-depression as compared with women without either condition (median [interquartile range], 20.44 [16.97-24.30] vs. 21.35 [17.33-26.01] ng/ml; P = 0.06). Compared to the referent group (those without PTSD and depression), women with comorbid PTSD-depression were 1.52-fold more likely to have low (<25.38 ng/ml) BDNF concentrations (OR = 1.52; 95 % CI 1.00-2.31). We observed no evidence of reduced BDNF concentrations among women with isolated PTSD. BDNF concentrations in early pregnancy were only minimally and non-significantly reduced among women with antepartum PTSD. Reductions in BDNF concentrations were more pronounced among women with comorbid PTSD-depression.

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.

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.

Brain-derived neurotrophic factor Val66met polymorphism and plasma levels in road traffic accident survivors

BACKGROUND

Alterations in brain-derived neurotrophic factor (BDNF) expression and release may play a role in the pathogenesis of post-traumatic stress disorder (PTSD).

DESIGN

This study evaluated road traffic accident (RTA) survivors to determine whether PTSD and trauma-related factors were associated with plasma BDNF levels and BDNF Val66Met carrier status following RTA exposure.

METHODS

One hundred and twenty-three RTA survivors (mean age 33.2 years, SD = 10.6 years; 56.9% male) were assessed 10 (SD = 4.9) days after RTA exposure. Acute stress disorder (ASD), as assessed with the Acute Stress Disorder Scale, was present in 50 (42.0%) of the participants. Plasma BDNF levels were measured with enzyme-linked immunosorbent assay and BDNF Val66Met genotyping was performed. PTSD, as assessed with the Clinician-Administered PTSD Scale, was present in 10 (10.8%) participants at 6 months follow-up.

RESULTS

Neither BDNF Val66Met genotype nor plasma BDNF was significantly associated with the presence or severity of ASD or PTSD. Plasma BDNF levels were, however, significantly correlated with the lifetime number of trauma exposures.

CONCLUSIONS

In RTA survivors, plasma BDNF levels increased with increasing number of prior trauma exposures. Plasma BDNF may, therefore, be a marker of trauma load.

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.

Agomelatine Increases BDNF Serum Levels in Depressed Patients in Correlation with the Improvement of Depressive Symptoms

BACKGROUND

Agomelatine modulates brain-derived neurotrophic factor expression via its interaction with melatonergic and serotonergic receptors and has shown promising results in terms of brain-derived neurotrophic factor increase in animal models.

METHODS

Twenty-seven patients were started on agomelatine (25mg/d). Venous blood was collected and brain-derived neurotrophic factor serum levels were measured at baseline and after 2 and 8 weeks along with a clinical assessment, including Hamilton Depression Rating Scale and Snaith-Hamilton Pleasure Scale.

RESULTS

Brain-derived neurotrophic factor serum concentration increased after agomelatine treatment. Responders showed a significant increase in brain-derived neurotrophic factor levels after 2 weeks of agomelatine treatment; no difference was observed in nonresponders. Linear regression analysis showed that more prominent brain-derived neurotrophic factor level variation was associated with lower baseline BDNF levels and greater anhedonic features at baseline.

CONCLUSIONS

Patients affected by depressive disorders showed an increase of brain-derived neurotrophic factor serum concentration after a 2-week treatment with agomelatine. The increase of brain-derived neurotrophic factor levels was found to be greater in patients with lower brain-derived neurotrophic factor levels and marked anhedonia at baseline.

Reduced severity of posttraumatic stress disorder associated with Val allele of Val66Met polymorphism at brain-derived neurotrophic factor gene among Chinese adolescents after Wenchuan earthquake

The aim of the present study was to longitudinally investigate the association of BDNF Val66Met with PTSD symptoms in Chinese Han adolescents who experienced the 2008 Wenchuan earthquake. Variants of BDNF Val66Met were identified by polymerase chain reaction-restriction fragment length polymorphism analyses and verified by DNA sequencing. PTSD symptoms were assessed by the PTSD Checklist-Civilian Version (PCL-C) among high school students at 6, 12, and 18 months after the earthquake. No differences of PTSD prevalence and PCL-C scores were found between the Val/Val homozygotes and the Met allele carriers at 6, 12, and 18 months after the earthquake regardless of gender. Decreased PTSD prevalence was observed at 12 and 18 months when compared with that at 6 months after the earthquake regardless of gender and the genotype. Meanwhile, PCL-C scores were decreased consecutively in the female subjects regardless of the genotypes. However, the scores at 18 months were lower when compared with those at 12 months in the male Val/Val homozygotes, but not in the male Met allele carriers. In addition, differences were found for the predictors of PCL-C scores and PTSD prevalence between the Val/Val homozygotes and the Met allele carriers during follow-up. These findings suggest that the association of BDNF Val66Met with PTSD is longitudinally different in Chinese Han adolescents after the 2008 Wenchuan earthquake. The Val allele may be associated with reduced PTSD severity in male adolescents in the later stage of PTSD rehabilitation during follow-up.

A Review of Posttraumatic Stress Disorder and Obesity: Exploring the Link

OBJECTIVE

The incidence of posttraumatic stress disorder (PTSD) and obesity are on the rise, and evidence continues to support the observation that individuals who have symptoms of PTSD are more likely to develop obesity in their lifetime. The incidence of obesity in individuals with PTSD, including war veterans, women, and children exposed to trauma, is not solely attributable to psychotropic medications, but actual pathophysiologic mechanisms have not been fully delineated. Additionally, there are no studies to date demonstrating that obese individuals are predisposed to developing PTSD compared to the general population. This review explores the pathogenic pathways common to both PTSD and obesity, which include inflammation, the renin-angiotensin-aldosterone system, cellular structures, and neuroendocrine activation.

DATA SOURCES AND SYNTHESIS

A PubMed search for the years 2000-2015 with the keywords PTSD and obesity was performed. There were no language restrictions.

RESULTS

More research is needed in human subjects to understand the pathogenic pathways common to both PTSD and obesity and to further clarify the direction of identified associations. Ideally, in the future, clinical interventions targeting these pathways may be able to modify the course of PTSD and obesity. The outcome of studies investigating the utility of angiotensin-converting enzyme inhibitors and angiotensin receptor blockers in the treatment of PTSD symptoms will be relevant to control both PTSD and obesity. Importantly, outcomes assessing inflammation, obesity, and cardiac function in the same subjects also should be determined.

CONCLUSION

Research is needed to reveal the multidimensional and intricate relationship between PTSD and obesity. The implications of this research would be essential for treatment, prevention, and potential public health reforms.

Brain-derived neurotropic factor polymorphisms, traumatic stress, mild traumatic brain injury, and combat exposure contribute to postdeployment traumatic stress

BACKGROUND

In addition to experiencing traumatic events while deployed in a combat environment, there are other factors that contribute to the development of posttraumatic stress disorder (PTSD) in military service members. This study explored the contribution of genetics, childhood environment, prior trauma, psychological, cognitive, and deployment factors to the development of traumatic stress following deployment.

METHODS

Both pre- and postdeployment data on 231 of 458 soldiers were analyzed. Postdeployment assessments occurred within 30 days from returning stateside and included a battery of psychological health, medical history, and demographic questionnaires; neurocognitive tests; and blood serum for the D2 dopamine receptor (DRD2), apolipoprotein E (APOE), and brain-derived neurotropic factor (BDNF) genes.

RESULTS

Soldiers who screened positive for traumatic stress at postdeployment had significantly higher scores in depression (d = 1.91), anxiety (d = 1.61), poor sleep quality (d = 0.92), postconcussion symptoms (d = 2.21), alcohol use (d = 0.63), traumatic life events (d = 0.42), and combat exposure (d = 0.91). BDNF Val66 Met genotype was significantly associated with risk for sustaining a mild traumatic brain injury (mTBI) and screening positive for traumatic stress. Predeployment traumatic stress, greater combat exposure and sustaining an mTBI while deployed, and the BDNF Met/Met genotype accounted for 22% of the variance of postdeployment PTSD scores (R (2)  = 0.22, P < 0.001). However, predeployment traumatic stress, alone, accounted for 17% of the postdeployment PTSD scores.

CONCLUSION

These findings suggest predeployment traumatic stress, genetic, and environmental factors have unique contributions to the development of combat-related traumatic stress in military service members.