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

Associations of TNF-RII rs1061622 With Post-Traumatic Stress Disorder and Their Interplays on Serum Lipids Levels in Adolescents

OBJECTIVE

To verify effects of rs1061622 at tumor necrosis factor-α receptor II (TNF-RII) gene (TNF-RII) on post-traumatic stress disorder (PTSD) and its interactive effects with PTSD on serum lipids levels in adolescents.

METHODS

PTSD was measured by PTSD Checklist-Civilian Version (PCL-C) in 699 adolescent survivors at 6 months after Wenchuan earthquake in China. A polymerase chain reaction and restriction fragment length polymorphism assay were utilized for TNF-RII rs1061622 genotyping followed by verification using DNA sequencing. Serum triglycerides (TG), total cholesterol (TC), high-density lipoprotein cholesterol (HDL-C), and low-density lipoprotein cholesterol were tested using routine methods.

RESULTS

G (deoxyguanine) allele carriers had higher PCL-C scores than TT (deoxythymidine) homozygotes in female subjects. Female adolescents had higher PCL-C scores than male subjects in TT homozygotes. Predictors of PTSD prevalence and severity were different between G allele carriers and TT homozygotes. Subjects with PTSD had lower TG, TG/HDL-C, TC/HDL-C, and higher HDL-C than adolescents without PTSD in male G allele carriers. G allele carriers had higher TG/HDL-C and TC/HDL-C than TT homozygotes in male adolescents without PTSD, and lower TG and TG/HDL-C in male PTSD patients. G allele carriers had higher TG than TT homozygotes only in female adolescents without PTSD.

CONCLUSION

These results suggest reciprocal actions of TNF-RII rs1061622 with other factors on PTSD severity, interplays of TNF-RII rs1061622 with PTSD on serum lipid levels, and novel treatment strategies for PTSD and comorbidities of PTSD with hyperlipidemia among adolescents with different genetic backgrounds of TNF-RII rs1061622 after experiencing traumatic events.

The influence of the BDNF Val66Met genotype on emotional recognition memory in post-traumatic stress disorder

Dysregulated consolidation of emotional memories is a core feature of posttraumatic stress disorder (PTSD). Brain Derived Neurotrophic Factor (BDNF) influences synaptic plasticity and emotional memory consolidation. The BDNF Val66Met polymorphism has been associated with PTSD risk and memory deficits respectively, although findings have been inconsistent, potentially due to a failure to control for important confounds such as sex, ethnicity, and the timing/extent of previous trauma experiences. Furthermore, very little research has examined the impact of BDNF genotypes on emotional memory in PTSD populations. This study investigated the interaction effects of Val66Met and PTSD symptomatology in an emotional recognition memory task in 234 participants divided into healthy control (n = 85), trauma exposed (TE: n = 105) and PTSD (n = 44) groups. Key findings revealed impaired negative recognition memory in PTSD compared to control and TE groups and in participants with the Val/Met compared to the Val/Val genotype. There was a group × genotype interaction showing no Met effect in the TE group despite significant effects in PTSD and controls. Results suggest that people previously exposed to trauma who do not develop PTSD may be protected from the BDNF Met effect, however more research is needed to replicate findings and to explore the epigenetic and neural processes involved.

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.

Neurobiology of BDNF in fear memory, sensitivity to stress, and stress-related disorders

Brain-derived neurotrophic factor (BDNF) is widely accepted for its involvement in resilience and antidepressant drug action, is a common genetic locus of risk for mental illnesses, and remains one of the most prominently studied molecules within psychiatry. Stress, which arguably remains the "lowest common denominator" risk factor for several mental illnesses, targets BDNF in disease-implicated brain regions and circuits. Altered stress-related responses have also been observed in animal models of BDNF deficiency in vivo, and BDNF is a common downstream intermediary for environmental factors that potentiate anxiety- and depressive-like behavior. However, BDNF's broad functionality has manifested a heterogeneous literature; likely reflecting that BDNF plays a hitherto under-recognized multifactorial role as both a regulator and target of stress hormone signaling within the brain. The role of BDNF in vulnerability to stress and stress-related disorders, such as posttraumatic stress disorder (PTSD), is a prominent example where inconsistent effects have emerged across numerous models, labs, and disciplines. In the current review we provide a contemporary update on the neurobiology of BDNF including new data from the behavioral neuroscience and neuropsychiatry literature on fear memory consolidation and extinction, stress, and PTSD. First we present an overview of recent advances in knowledge on the role of BDNF within the fear circuitry, as well as address mounting evidence whereby stress hormones interact with endogenous BDNF-TrkB signaling to alter brain homeostasis. Glucocorticoid signaling also acutely recruits BDNF to enhance the expression of fear memory. We then include observations that the functional common BDNF Val66Met polymorphism modulates stress susceptibility as well as stress-related and stress-inducible neuropsychiatric endophenotypes in both man and mouse. We conclude by proposing a BDNF stress-sensitivity hypothesis, which posits that disruption of endogenous BDNF activity by common factors (such as the BDNF Val66Met variant) potentiates sensitivity to stress and, by extension, vulnerability to stress-inducible illnesses. Thus, BDNF may induce plasticity to deleteriously promote the encoding of fear and trauma but, conversely, also enable adaptive plasticity during extinction learning to suppress PTSD-like fear responses. Ergo regulators of BDNF availability, such as the Val66Met polymorphism, may orchestrate sensitivity to stress, trauma, and risk of stress-induced disorders such as PTSD. Given an increasing interest in personalized psychiatry and clinically complex cases, this model provides a framework from which to experimentally disentangle the causal actions of BDNF in stress responses, which likely interact to potentiate, produce, and impair treatment of, stress-related psychiatric disorders.

Influence of childhood trauma and brain-derived neurotrophic factor Val66Met polymorphism on posttraumatic stress symptoms and cortical thickness

Interaction between childhood trauma and genetic factors influences the pathophysiology of posttraumatic stress disorder (PTSD). This study examined the interaction effect of childhood trauma and brain-derived neurotrophic factor (BDNF) Val66Met polymorphism on PTSD symptoms and brain cortical thickness. A total of 216 participants (133 healthy volunteers and 83 PTSD patients) were recruited. T1-weighted structural magnetic resonance imaging, BDNF rs6265 genotyping through blood sampling, and clinical assessments including the childhood trauma questionnaire (CTQ) and posttraumatic stress disorder Checklist (PCL) were performed. A moderated regression analysis, two-way multivariate analysis of covariance, and correlation analysis were conducted. An interaction between the CTQ and the BDNF polymorphism significantly influenced PTSD symptom severity. In fact, people with rs6265 Val/Val genotype and higher CTQ scores showed higher PCL scores. Additionally, this interaction was significant on both left fusiform and transverse temporal gyri thickness. Furthermore, the thickness of both brain regions was significantly correlated with psychological symptoms including depression, anxiety, rumination, and cognitive emotion regulation methods; yet this was mainly observed in people with the Val/Val genotype. The interaction between childhood trauma and BDNF polymorphism significantly influences both PTSD symptoms and cortical thickness and the Val/Val genotype may increase the risk in Korean population.

Interplays of estrogen receptor alpha gene rs2234693 with post-traumatic stress disorder influence serum glucose and lipids profiles in Chinese adolescents

Both post-traumatic stress disorder (PTSD) and estrogen receptor alpha (ESR1) gene rs2234693 were reported to influence serum glucose and lipids profiles. However, their interactions on serum glucose and lipids profiles have not been reported. A total of 708 Chinese Han high school students were recruited at 6th months after the 2008 Wenchuan Earthquake. Serum concentrations of fasting blood glucose (FBG), fasting blood insulin (FBI), total cholesterol (TC), triglyceride (TG), low-density lipoprotein cholesterol (LDL-C) and high-density lipoprotein cholesterol (HDL-C) were detected. Body mass index (BMI) and homeostatic model assessment of insulin resistance (HOMA-IR) were calculated. PTSD was assessed by the PTSD Checklist Civilian Version (PCL-C). Variants of ESR1 rs2234693 was analyzed by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) analyses and verified by DNA sequencing. The male subjects with PTSD had a trend of higher FBG (p = 0.077) and significantly higher FBI and HOMA-IR than male controls. The PTSD subjects had significantly higher levels of FBG, FBI, HOMA-IR and HDL-C than the controls only in the male C allele carriers irrespective of adjustment for age and BMI. In the male controls group, the C allele carriers had significantly lower HDL-C than the TT homozygotes regardless of adjustment for age and BMI. In female PTSD group, the C allele carriers had significantly higher TC/HDL-C and LDL-C/HDL-C than the TT homozygotes after adjustment for age and BMI. These results suggest the interplays of ESR1 rs2234693 with PTSD influence serum glucose and lipids profiles with a gender dependent manner.

Correlations of Four Genetic Single Nucleotide Polymorphisms in Brain-Derived Neurotrophic Factor with Posttraumatic Stress Disorder

OBJECTIVE

To investigate the correlations of four genetic single nucleotide polymorphisms (SNPs) of brain-derived neurotrophic factor (BDNF) with posttraumatic stress disorder (PTSD).

METHODS

A total of 300 patients with sporadic PTSD and 150 healthy subjects (the control group) were selected according to the diagnostic criteria of PTSD (DSM-IV), and the genotypes of the BDNF SNPs G-712A, C270T, rs6265, and rs7103411 were detected by polymerase chain reaction and direct DNA sequencing to determine intergroup differences in the genotypes and allele frequencies; the p values were corrected with the permutation test.

RESULTS

The genotypes and allele frequencies of the SNPs G-712A, rs6265, and rs7103411 of BDNF showed no significant intergroup differences (p>0.05). However, the genotype and allele frequencies of C270T showed significant differences between the PTSD group and the control group (p<0.05).

CONCLUSION

The SNP C270T of BDNF may be associated with PTSD. Individuals carrying the polymorphic T allele of C270T may be more likely to suffer from PTSD.

Longitudinal interplays of estrogen receptor alpha gene rs9340799 with social-environmental factors on post-traumatic stress disorder in Chinese Han adolescents after Wenchuan earthquake

Indirect evidences suggested associations of estrogen receptor alpha (ESR1) with post-traumatic stress disorder (PTSD). However, the relationship between rs9340799 on ESR1 gene and PTSD has not been reported yet. The present study was to explore the longitudinal changes of prevalence and severity of PTSD in adolescents with different genotypes of rs9340799 after the 2008 Wenchuan earthquake. Social-environmental factors were collected by questionnaires in 465 high school students. Variants of rs9340799 were determined by polymerase chain reaction-restriction fragment length polymorphism analyses and verified by DNA sequencing. PTSD symptoms were assessed by PTSD Checklist-Civilian Version (PCL-C) at 6, 12, and 18 months after the earthquake. The female AA homozygotes had a trend of higher prevalence of PTSD and significantly higher PCL-C scores than the female G allele carriers at 6 months after the earthquake. The female students had higher prevalence of PTSD and higher PCL-C scores than the male subjects at 6 months in the AA homozygotes, but not in the G allele carriers. Consecutive decreases in PCL-C scores were observed only in the female AA homozygotes. Only in the female, the AA genotype was the risk factor and predictor of PCL-C scores at 6 months. Potential factors of PTSD prevalence and predictors of PCL-C scores were different between the AA homozygotes and G allele carriers at different time during the follow-up. These results suggest gene-environment interactions may occur among rs9340799 and social-environmental factors, and influence the development and natural rehabilitation of PTSD in the course after stressed by the earthquake.

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.

Association between social support and post-traumatic stress disorder symptoms among Chinese patients with ovarian cancer: A multiple mediation model

Post-traumatic stress disorder (PTSD) symptoms can develop after person experiences one or more traumatic events. Little research, however, has been done on PTSD symptoms of patients with ovarian cancer. The present study aimed to estimate the prevalence of PTSD symptoms in patients with ovarian cancer in China; the effects of demographic and clinical variables on PTSD symptoms; multiple mediation roles in the association between social support and PTSD symptoms in patients with ovarian cancer in China. We collected demographic and clinical information of patients with ovarian cancer in the first and second hospitals of China Medical University between January 1, 2014 and December 31, 2015. Qualified patients were asked to complete the Posttraumatic Stress Disorder Checklist-Civilian Version (PCL-C), Duke-UNC Functional Social Support Questionnaire, Herth Hope Index (HHI), and Resilience Scale-14 (RS-14). 201 patients provided responses. We performed hierarchical linear regression to assess the correlation between social support and PTSD symptoms and bootstrapping to test the mediating role of hope and resilience as potential mediators. After controlling demographic and clinical characteristics, social support negatively correlated with PTSD symptoms (β = -0.406, P < 0.01). Social support explained 14.7% of the variance in PTSD symptoms. Hope and resilience explained 17.0% of the variance in PTSD symptoms. The proportion of the hope mediating effect was 43.37% for social support and the proportion of the resilience mediating effect was 10.64% for social support. Hope and resilience partly mediated the correlation between social support and PTSD symptoms despite accounting for different proportions of the mediating effect. Future intervention plans should pay more attention to social support as well as hope and resilience to prevent, relieve and treat PTSD symptoms.

The Effects of a BDNF Val66Met Polymorphism on Posttraumatic Stress Disorder: A Meta-Analysis

OBJECTIVE

Given evidence that posttraumatic stress disorder (PTSD) is moderately heritable, a number of studies utilizing candidate gene approaches have attempted to examine the potential contributions of theoretically relevant genetic variation. Some of these studies have found sup port for a brain-derived neurotrophic factor (BDNF) variant, Val66Met, in the risk of developing PTSD, while others have failed to find this link.

METHODS

This study sought to reconcile these conflicting findings using a meta-analysis framework. Analyses were also used to determine whether there is significant heterogeneity in the link between this variant and PTSD. We conducted a systematic review of the literature on BDNF and PTSD from the PsycINFO and PubMed databases. A total of 11 studies were included in the analysis.

RESULTS

Findings indicate a marginally significant effect of the BDNF Val66Met variant on PTSD (p < 0.1). However, of the 11 studies included, only 2 suggested an effect with a non-zero confidence interval, one of which showed a z score of 3.31. We did not find any evidence for heterogeneity.

CONCLUSIONS

Findings from this meta-analytic investigation of the published literature provide little support for the Val66Met variant of BDNF as a predictor of PTSD. Future well-powered agnostic genome-wide association studies with more refined phenotyping are needed to clarify genetic influences on PTSD.

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.

A Case-Control Study and Meta-Analysis Reveal BDNF Val66Met Is a Possible Risk Factor for PTSD

Posttraumatic stress disorder (PTSD) is a debilitating condition that develops in some people after exposure to a traumatic event. Brain-derived neurotrophic factor (BDNF) is highly expressed in the mammalian brain and is thought to be involved in learning and memory processes. A nonsynonymous polymorphism in the BDNF gene, rs6265 (Val66Met), has been hypothesised to be associated with PTSD. Association studies examining the Val66Met polymorphism and PTSD have been inconclusive, likely due to the variability in type of trauma exposure analysed. Vietnam veterans (n = 257) screened for PTSD and controlled for trauma exposure were genotyped for BDNF Val66Met. The association was not significant so we incorporated our data into a meta-analysis to obtain greater statistical power. A comprehensive search of more than 1237 articles revealed eight additional studies suitable for meta-analysis (n = 3625). A random-effects meta-analysis observed a potential protective factor of the Val/Val genotype. After removing two studies with violation of Hardy-Weinberg equilibrium, findings for the Val/Val genotype reached significance. Subgroup analyses confirmed a trend for this finding. Limitations of some studies that inform this meta-analysis include poorly screened controls and a lack of examination of population stratification. Effectively designed studies should inform this line of research in the future.