PTSD and traumatic stress from gene to community and bench to bedside

A Public Health Perspective of Post-Traumatic Stress Disorder

Trauma exposure is one of the most important and prevalent risk factors for mental and physical ill-health. Prolonged or excessive stress exposure increases the risk of a wide variety of mental and physical symptoms, resulting in a condition known as post-traumatic stress disorder (PTSD). The diagnosis might be challenging due to the complex pathophysiology and co-existence with other mental disorders. The prime factor for PTSD development is exposure to a stressor, which variably, along with peritraumatic conditions, affects disease progression and severity. Additionally, many factors are thought to influence the response to the stressor, and hence reshape the natural history and course of the disease. With sufficient knowledge about the disease, preventive and intervenient methods can be implemented to improve the quality of life of the patients and to limit both the medical and economic burden of the disease. This literature review provides a highlight of up-to-date literature on traumatic stress, with a focus on causes or triggers of stress, factors that influence response to stress, disease burden, and the application of the social-ecological public health model of disease prevention. In addition, it addresses therapeutic aspects, ethnic differences in traumatic stress, and future perspectives, including potential biomarkers.

Anxiolytic and antidepressant-like effects of monoterpene tetrahydrolinalool and in silico approach of new potential targets

INTRODUCTION- The drugs currently available for treatment of anxiety and depression act through modulation of the neurotransmission systems involved in the neurobiology of the disorder, yet they of-ten present side effects, which can impair patient adherence to treatment. METHOD- This, has driven the search for new molecules with anxiolytic and antidepressant potential. Aromatic plants are rich in essential oils, and their chemical constituents, such as monoterpenes, are be-ing studied for these disorders. This study aims to evaluate the anxiolytic and antidepressant-like poten-tial of the monoterpene tetrahydrolinalool in in vivo animal models, and review pharmacological targets with validation through molecular docking. Male Swiss mice (Mus musculus) were treated with THL (37.5-600 mg kg-1 p.o.) and submitted to the elevated plus maze, open field, rota rod, and forced swim tests. In the elevated plus-maze, THL at doses of 37.5 and 75 mg kg-1 induced a significant increase in the percentage of entries (72.7 and 64.3% respectively), and lengths of stay (80.3 and 76.8% respective-ly) in the open arms tests. RESULT- These doses did not compromise locomotor activity or motor coordination in the animals. In the open field, rota rod tests, and the forced swimming model, treatment with THL significantly reduced immobility times at doses of 150, 300, and 600 mg kg-1, and by respective percentages of 69.3, 60.9 and 68.7%. CONCLUSION- In molecular docking assay, which investigated potential targets, THL presented sat-isfactory energy values for: nNOs, SGC, IL-6, 5-HT1A, NMDAr, and D1. These demonstrate the po-tential of THL (a derivative of natural origin) in in vivo and in silico models, making it a drug candidate.

Powerful Stress Relieving Medicinal Plants for Anger, Anxiety, Depression, and Stress During Global Pandemic

Consideration and improvement for anxiety and depression are important during a global pandemic. Appropriate healthcare can be obtained by paying more attention to traditional medicinal sciences. The adverse effects of stress with various symptoms can be managed by introducing plants that boost mental health. The most relevant psychological reactions in the general population related to the global pandemic are pervasive anxiety, frustration and boredom, specific and uncontrolled fear, disabling loneliness, significant lifestyle changes, and psychiatric conditions. Ginseng, chamomile, passionflower, herbal tea, lavender, saffron, kava, rose, cardamom, Chinese date, and some chief formula like yokukansan, Dan-zhi-xiao-yao-san, so-ochim-tang-gamiband, and saikokaryukotsuboreito are notable herbal treatments for mental health problems. The most common medicinal plants that have been used in Iran for the cure of stress and anxiety are Viper's-buglosses, Dracocephalum, valerian, chamomile, common hop, hawthorns, and lavender. Medicinal plants and herbs can be used for the treatment and alleviation of the negative effects of stress, anger, and depression during the global pandemic.

Cannabidiol and the corticoraphe circuit in post-traumatic stress disorder

Post-Traumatic Stress Disorder (PTSD), characterized by re-experiencing, avoidance, negative affect, and impaired memory processing, may develop after traumatic events. PTSD is complicated by impaired plasticity and medial prefrontal cortex (mPFC) activity, hyperactivity of the amygdala, and impaired fear extinction. Cannabidiol (CBD) is a promising candidate for treatment due to its multimodal action that enhances plasticity and calms hyperexcitability. CBD’s mechanism in the mPFC of PTSD patients has been explored extensively, but literature on the mechanism in the dorsal raphe nucleus (DRN) is lacking. Following the PRISMA guidelines, we examined current literature regarding CBD in PTSD and overlapping symptomologies to propose a mechanism by which CBD treats PTSD via corticoraphe circuit. Acute CBD inhibits excess 5-HT release from DRN to amygdala and releases anandamide (AEA) onto amygdala inputs. By first reducing amygdala and DRN hyperactivity, CBD begins to ameliorate activity disparity between mPFC and amygdala. Chronic CBD recruits the mPFC, creating harmonious corticoraphe signaling. DRN releases enough 5-HT to ameliorate mPFC hypoactivity, while the mPFC continuously excites DRN 5-HT neurons via glutamate. Meanwhile, AEA regulates corticoraphe activity to stabilize signaling. AEA prevents DRN GABAergic interneurons from inhibiting 5-HT release so the DRN can assist the mPFC in overcoming its hypoactivity. DRN-mediated restoration of mPFC activity underlies CBD’s mechanism on fear extinction and learning of stress coping.

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CBD reduces PTSD symptoms via the DRN and corticoraphe circuit.

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Acute effects of CBD reduce DRN-amygdala excitatory signaling to lessen the activity disparity between amygdala and mPFC.

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Chronic CBD officially resolves mPFC hypoactivity by facilitating 5-HT release from DRN to mPFC.

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CBD-facilitated endocannabinoid signaling stabilizes DRN activity and restores mPFC inhibitory control.

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Chronically administered CBD acts via the corticoraphe circuit to favor fear extinction over fear memory reconsolidation.

COVID-19 impact on high school student’s education and mental health: A cohort survey in China

BACKGROUND

The ongoing coronavirus disease 2019 (COVID-19) pandemic and the universal implementation of control measures are fundamentally affecting every aspect of our society and daily lives.

AIM

To evaluate the prevalence of post-traumatic stress disorder symptoms and their associated factors as well as the effects and attitudes towards online education in Chinese high school students.

METHODS

A total of 883 students were included. The first, second and third-year students of a high school in Lanzhou, Gansu province of China were invited to participate in this study. They were requested to involve their parents to complete the survey together. A detailed questionnaire of 65 questions was designed and divided into five sections. The survey was anonymously conducted via WeChat, a Chinese multipurpose messaging, social media and mobile payment app.

RESULTS

Overall, 32.94% of students experienced post-traumatic stress disorder due to the COVID-19 epidemic. The majority of students (60.82%) felt that online education was not (10.76%) or less effective (50.06%) in terms of gaining knowledge and improving practical and communications skills. Correlation analysis revealed that the class level, residential background and whether living with parents were significantly linked with the effectiveness and satisfaction of the online education system. Of the final year students, 74.2% said that the COVID-19 outbreak has negatively affected their preparation for the college entrance exam, and 68% of students felt that this outbreak increased psychological pressure for their college entrance examination preparation. In case of having COVID-19 symptoms during the exam, 50.7%, 13.3%, and 10.2% would notify the proctor, teacher and parents, respectively.

CONCLUSION

We found a high prevalence rate of post-traumatic stress disorder symptoms in high school students. Thus, our results call for urgent attention from both government and schools to implement effective interventions to cope with the psychological effects and the disturbance of education by COVID-19 on children.

The Collateral Impact of COVID-19 Emergency on Neonatal Intensive Care Units and Family-Centered Care: Challenges and Opportunities

The ongoing Coronavirus disease 2019 (COVID-19) pandemic is disrupting most specialized healthcare services worldwide, including those for high-risk newborns and their families. Due to the risk of contagion, critically ill infants, relatives and professionals attending neonatal intensive care units (NICUs) are undergoing a profound remodeling of the organization and quality of care. In particular, mitigation strategies adopted to combat the COVID-19 pandemic may hinder the implementation of family-centered care within the NICU. This may put newborns at risk for several adverse effects, e.g., less weight gain, more nosocomial infections, increased length of NICU stay as well as long-term worse cognitive, emotional, and social development. This article aims to contribute to deepening the knowledge on the psychological impact of COVID-19 on parents and NICU staff members based on empirical data from the literature. We also provided evidence-based indications on how to safely empower families and support NICU staff facing such a threatening emergency, while preserving the crucial role of family-centered developmental care practices.

The impact of COVID-19 pandemic outbreak on education and mental health of Chinese children aged 7-15 years: an online survey

BACKGROUND

The emerging of psychological problems triggered by COVID-19 particularly in children have been extensively highlighted and emphasized, but original research in this respect is still lagging behind. Therefore, we designed this study to evaluate the impact of COVID-19 pandemic on mental health and the effectiveness and attitudes towards online education among Chinese children aged 7-15 years.

METHODS

A detailed questionnaire, comprising of 62 questions was designed and parents or caretakers of 7 to 15 years old children were invited to participate via WeChat, a multi-purpose messaging, social media and mobile payment app, which is widely used by the Chinese population. A total of 668 parents across different regions of China were included.

RESULTS

During COVID-19 pandemic, 20.7 and 7.2% children report experiencing post-traumatic stress disorder (PTSD) and depressive symptoms due to the COVID-19 pandemic. PTSD and SMFQ-P scores are significantly higher in middle school and boarding school students compared to primary and day school students. Multiple logistic regression analysis revealed that school system and province of origin are factors significantly associated with developing PSTD symptoms. 44.3% respondents feel online education is effective in gaining knowledge and improving practical and communications skills. 78.0% believe the online education system is efficient. Overall 79.8% respondents are satisfied and children can adapt to this new education system. During the COVID-19 pandemic, we found 1 in five children have PTSD and 1 in 14 children have depressive symptoms.

CONCLUSION

In summary, COVID-19 epidemic has caused PTSD and depression symptoms among Chinese children aged 7 to 15 years. In general, a large proportion of respondents are satisfied with online education, but still a substantial proportion of students are not comfortable with this new form of learning. Authorities should optimize online education systems and implement effective interventions to cope with the psychological effects of COVID-19 on children, as it is affecting the global population and remains uncertain when it will end.

Traditional herbal medicines to overcome stress, anxiety and improve mental health in outbreaks of human coronaviruses

Mental health condition is including depression and anxiety, and they may impact wellbeing, personal relationships and productivity of both genders. Herbal medicines have been used to treatment of anxiety and depression symptoms for centuries. SARS, MERS and COVID-19 are related to coronavirus types. SARS (sever acute respiratory syndrome, China, 2002), MERS (Middle East respiratory syndrome, Saudi Arabia, 2012), and SARS-CoV-2 (2019-2020) are the main coronavirus outbreaks. Both anxiety and depression are more serious to be considered and improved for all general public during fight with these diseases. In this mini-review article, we have mentioned the key role some of the most important plants and herbs for treatment of stress and anxiety and improve mental health against SARS and SARS-CoV-2 on the basis of traditional Asian medicine, especially traditional Chinese and Persian medicine.

Four Actionable Bottlenecks and Potential Solutions to Translating Psychiatric Genetics Research: An Expert Review

BACKGROUND

Psychiatric genetics has had limited success in translational efforts. A thorough understanding of the present state of translation in this field will be useful in the facilitation and assessment of future translational progress.

PURPOSE

A narrative literature review was conducted. Combinations of 3 groups of terms were searched in EBSCOhost, Google Scholar, and PubMed. The review occurred in multiple steps, including abstract collection, inclusion/exclusion criteria review, coding, and analysis of included papers.

RESULTS

One hundred and fourteen articles were analyzed for the narrative review. Across those, 4 bottlenecks were noted that, if addressed, may provide insights and help improve and increase translation in the field of psychiatric genetics. These 4 bottlenecks are emphasizing linear translational frameworks, relying on molecular genomic findings, prioritizing certain psychiatric disorders, and publishing more reviews than experiments.

CONCLUSIONS

These entwined bottlenecks are examined with one another. Awareness of these bottlenecks can inform stakeholders who work to translate and/or utilize psychiatric genetic information. Potential solutions include utilizing nonlinear translational frameworks as well as a wider array of psychiatric genetic information (e.g., family history and gene-environment interplay) in this area of research, expanding which psychiatric disorders are considered for translation, and when possible, conducting original research. Researchers are urged to consider how their research is translational in the context of the frameworks, genetic information, and psychiatric disorders discussed in this review. At a broader level, these efforts should be supported with translational efforts in funding and policy shifts.

Psychological status of parents of hospitalized children during the COVID-19 epidemic in China

A series of unexplained pneumonia appeared in Wuhan, Hubei Province, China, which is highly contagious. The virus is prone to nervous and anxious psychological reactions. In the objective environment of complex and densely populated hospitals, it is a high-risk area for virus-transmitted infections and children generally have lower immunity who are more likely to develop infections. The results showed that the mental health problems of parents of hospitalized children during the epidemic were more serious, and the anxiety and depression were more obvious.

[Injury characteristics and therapeutic strategy of patients injured in "8·8" Jiuzhaigou earthquake]

Objective

To summarize the injury characteristics and therapeutic strategy of patients injured in "8·8" Jiuzhaigou earthquake.

Methods

The clinical data of 48 patients injured in "8·8" Jiuzhaigou earthquake who were admitted to Mianyang Central Hospital were analyzed retrospectively. There were 25 males and 23 females with an average age of 36 years (range, 5-87 years). The average interval from injury to admission was 30 hours (range, 3-53 hours). The patients from Sichuan province accounted for 45.8% (22 cases), from other province for 52.1% (25 cases), and from abroad for 2.1% (1 case). Patients were primarily hurted by collapsing houses and flying stones. Thirty-seven patients (77.1%) had single injury, mainly involving 36 patients (75.0%) in limbs, and the other 11 patients (22.9%) had multiple injuries. Ten patients (20.8%) had open fractures, including 1 case rated as typeⅠ, 2 as typeⅡ, 3 as type Ⅲa, 2 as type Ⅲb, and 2 as type Ⅲc according to Gustilo classification criteria. The abbreviated injury scale (AIS) score was 2-3 in 37 patients of single injury, and the injury severity score (ISS) was 8-22 (mean, 13.2) in 11 patients of multiple injuries. Sixteen patients (33.3%) were diagnosed as mental disorders by Hamilton rating scale for anxiety (HAMA), including 8 cases had their anxiety scores≥29, 4 cases of 21-28, 3 cases of 14-20, and 1 case of 7-13. Of the 16 patients, 2 showed suicidal tendency.

Results

Except 2 referrals, 30 patients received operation［28 patients (93.3%) for orthopaedic surgeries］and 16 patients received conservative treatment. The procedures included internal fixation, soft tissue debridement, external fixation, bipolar femoral head replacement, embolization of carotid cavernous sinus arteriovenous fistula, and amputation. Among the 46 patients treated in this hospital, 21 discharged from hospital at 2-12 days (mean, 6.7 days) after admission, the others received further rehabilitation in this hospital or local hospital. No undesirable consequence occurred in 16 patients with mental disorders. Five cases of infection occurred out of hospital were cured after debridement. No dead and nosocomial infection case reported.

Conclusion

Intensive treatment, specialist management, multidisciplinary team, and early intervention of nosocomial infection and deep venous thrombosis are the key to improve the general level of successful earthquake medical rescue.

Traumatic stress affects alcohol‑drinking behavior through cocaine‑ and amphetamine‑regulated transcript 55‑102 in the paraventricular nucleus in rats

Cumulative evidence has suggested an association between stress and alcohol self‑administration; however, less is known about the role of traumatic stress in alcohol drinking behavior. It has been reported that cocaine‑ and amphetamine‑regulated transcript (CART) 55‑102 may be involved in mediating stress responses and regulating reward and reinforcement. The aim of the present study was to evaluate the role of CART 55‑102 in alcohol drinking behavior of rats in the presence or absence of traumatic stress. Alcohol drinking behavior was examined using the two‑bottle choice drinking paradigm (one bottle contained 10% alcohol and the other contained filtered water), which was initiated 1, 3 and 7 days post‑trauma (T1, T3 and T7), for 14 days in rats; the control group was initiated from T0. The results indicated that exposure to trauma significantly increased alcohol consumption and preference, particularly drinking from T3. Immunohistochemistry revealed that the lowest level of CART 55‑102 immunoreactivity within the paraventricular nucleus (PVN) was exhibited in the T3 group. Additionally, an intra‑PVN injection of CART 55‑102 attenuated alcohol‑drinking behavior in a dose‑dependent manner, in the T3 group. Furthermore, the significant increase in circulating adrenocorticotrophic hormone (ACTH) and corticosterone (CORT) concentrations in the T3 group were inhibited by CART 55‑102 administration to the PVN, in particular CORT levels were significantly decreased. Positive correlations between alcohol preference and ACTH and CORT levels were also observed. These results indicated that CART 55‑102 in the PVN serves an inhibitory role in traumatic stress‑induced alcohol drinking behavior, possibly through disturbing hypothalamus‑pituitary‑adrenal axis hyperactivity.

Should Posttraumatic Stress Be a Disorder or a Specifier? Towards Improved Nosology Within the DSM Categorical Classification System

PURPOSE OF REVIEW

Since 1980, posttraumatic stress (PTS) disorder has been controversial because of its origin as a social construct, its discriminating trauma definition, and the Procrustean array of symptoms/clusters chosen for inclusion/exclusion. This review summarizes the history of trauma-related nosology and proposed changes, within current categorical models (trauma definitions, symptoms/clusters, subtypes/specifiers, disorders) and new models.

RECENT FINDINGS

Considering that trauma is a risk factor for virtually all mental disorders (particularly depressive, anxiety, dissociative, personality), the multi-finality of trauma (some survivors are resilient, and some develop PTS and/or non-PTS symptoms), and the various symptoms that trauma survivors express (mood, cognitive, perceptual, somatic), it is difficult to classify PTS. Because the human mind best comprehends categories, reliable classification generally necessitates using a categorical nosology but PTS defies categories (internalizing and/or externalizing, fear-based and/or numbing symptoms), the authors conclude that PTS-like DSM-5's panic attacks specifier-is currently best conceptualized as a specifier for other mental disorders.

Assessment of functional tag single nucleotide polymorphisms within the DRD2 gene as risk factors for post-traumatic stress disorder in the Han Chinese population

BACKGROUND

Gene variations related to the dopaminergic pathway have been implicated in a number of neuropsychiatric disorders, including post-traumatic stress disorder (PTSD). Dopamine D2 receptor (DRD2) has been shown to significantly contribute to neuropsychiatric disorders and may specifically contribute to predisposition to PTSD. This study aimed to evaluate the association of polymorphisms within the entire DRD2 gene with PTSD in a case-control study.

MATERIALS AND METHODS

A total of 834 unrelated Han Chinese adults, including 497 healthy volunteers and 337 patients with PTSD, were used in this study. Fifteen tag single-nucleotide polymorphisms (tSNPs) were selected spanning the entire DRD2 gene through the construction of haplotype bins. Genotypes were gathered using an improved multiplex ligation detection reaction (iMLDR) technique. Allelic frequencies and clinical characteristics were compared in two independent Han Chinese populations. Moreover, the functionality of the rs2075652 and rs7131056 polymorphisms were assessed by measuring transcriptional enhancer activities.

RESULTS

Fifteen tag SNPs were identified in the Han Chinese population and all were common SNPs. Among 15 tSNPs, two of them (rs2075652 and rs7131056) significantly associated with PTSD. PTSD individuals were more likely to carry the rs2075652A and rs7131056A allele compared to the controls (P<0.05). The haplotype GTGATCGCGCAGGCG, had a risk effect on PTSD occurrence (OR=1.75, 95% CI: 1.24-2.48, P=0.002). Additionally, the rs2075652 polymorphism contained intronic enhancer activities.

CONCLUSIONS

The rs2075652 and rs7131056 polymorphisms, and the haplotype GTGATCGCGCAGGCG within the DRD2 gene, may be potential markers to predict susceptibility to PTSD.

Preliminary, open-label, pilot study of add-on oral Δ9-tetrahydrocannabinol in chronic post-traumatic stress disorder

BACKGROUND AND OBJECTIVES

Many patients with post-traumatic stress disorder (PTSD) achieve but partial remission with current treatments. Patients with unremitted PTSD show high rates of substance abuse. Marijuana is often used as compassion add-on therapy for treatment-resistant PTSD. This open-label study evaluates the tolerance and safety of orally absorbable Δ(9)-tetrahydrocannabinol (THC) for chronic PTSD.

METHODS

Ten outpatients with chronic PTSD, on stable medication, received 5 mg of Δ(9)-THC twice a day as add-on treatment.

RESULTS

There were mild adverse effects in three patients, none of which led to treatment discontinuation. The intervention caused a statistically significant improvement in global symptom severity, sleep quality, frequency of nightmares, and PTSD hyperarousal symptoms.

CONCLUSIONS

Orally absorbable Δ(9)-THC was safe and well tolerated by patients with chronic PTSD.

Preclinical perspectives on posttraumatic stress disorder criteria in DSM-5

Posttraumatic stress disorder (PTSD) now sits within the newly created "Trauma- and Stressor-Related Disorders" section of the Diagnostic and Statistical Manual of Mental Disorders (fifth edition; DSM-5). Through the refinement and expansion of diagnostic criteria, the DSM-5 version better clarifies the broad and pervasive effects of trauma on functioning, as well as the impact of development on trauma reactions. Aggressive and dissociative symptoms are more thoroughly characterized, reflecting increasing evidence that reactions to trauma often reach beyond the domains of fear and anxiety (these latter domains were emphasized in DSM-IV). These revised criteria are supported by decades of preclinical and clinical research quantifying traumatic stress-induced changes in neurobiological and behavioral function. Several features of the DSM-5 PTSD criteria are similarly and consistently represented in preclinical animal models and humans following exposure to extreme stress. In rodent models, for example, increases in anxiety-like, helplessness, or aggressive behavior, along with disruptions in circadian/neurovegetative function, are typically induced by severe, inescapable, and uncontrollable stress. These abnormalities are prominent features of PTSD and can help us in understanding the pathophysiology of this and other stress-associated psychiatric disorders. In this article we examine some of the changes to the diagnostic criteria of PTSD in the context of trauma-related neurobiological dysfunction, and discuss implications for how preclinical data can be useful in current and future clinical conceptualizations of trauma and trauma-related psychiatric disorders.

Effects of L-theanine on posttraumatic stress disorder induced changes in rat brain gene expression

Posttraumatic stress disorder (PTSD) is characterized by the occurrence of a traumatic event that is beyond the normal range of human experience. The future of PTSD treatment may specifically target the molecular mechanisms of PTSD. In the US, approximately 20% of adults report taking herbal products to treat medical illnesses. L-theanine is the amino acid in green tea primarily responsible for relaxation effects. No studies have evaluated the potential therapeutic properties of herbal medications on gene expression in PTSD. We evaluated gene expression in PTSD-induced changes in the amygdala and hippocampus of Sprague-Dawley rats. The rats were assigned to PTSD-stressed and nonstressed groups that received either saline, midazolam, L-theanine, or L-theanine + midazolam. Amygdala and hippocampus tissue samples were analyzed for changes in gene expression. One-way ANOVA was used to detect significant difference between groups in the amygdala and hippocampus. Of 88 genes examined, 17 had a large effect size greater than 0.138. Of these, 3 genes in the hippocampus and 5 genes in the amygdala were considered significant (P < 0.05) between the groups. RT-PCR analysis revealed significant changes between groups in several genes implicated in a variety of disorders ranging from PTSD, anxiety, mood disorders, and substance dependence.

Possible association of Toll-like receptor 9 polymorphisms with cytokine levels and posttraumatic symptoms in individuals with various types of orthopaedic trauma: early findings

BACKGROUND

Although TLR9 polymorphisms may be associated with cytokine dysregulation, its role in regulation of cytokines due to bodily trauma or in relation to acute stress symptoms or posttraumatic stress symptoms (ASS/PTS) has not been evaluated.

AIMS

To assess serum cytokine levels and levels of ASS and PTS in relation to four common TLR9 single-nucleotide polymorphisms (SNPs) in individuals with various types of orthopaedic trauma.

METHODS

Forty-eight accident-injured individuals, aged 20-60 years were studied. Serum cytokine levels and TLR9 SNPS (1486T/C, 1237T/C, 1174G/A and 2848G/A) were assessed together with intensity of ASS and PTS symptoms.

RESULTS

Statistically significant higher serum levels of IL-12 and IL-1β (p<.05) were found in individuals heterozygous for TLR9-1237 (TC) than in individuals expressing the most common TLR9-1237 type (TT), while differences in levels of IL-6 were not significant. Also, marginally significant levels of IL-6 were found in individuals expressing the common TLR9-1174 (GG) compared with individuals homozygous (AA) or heterozygous (GA) for this SNP. They also had non-significant higher intensity of ASS symptoms. A trend of higher PTS levels in individuals expressing the most common type TLR9-1174 (GG) was found, contrary to homozygous (AA) and heterozygous individuals (GA).

CONCLUSIONS

The results of this pilot study suggest that accident-injured individuals with certain TLR9 polymorphisms express higher levels of pro-inflammatory cytokines (IL-1β, IL-6 and IL-12). The associations of TLR9 SNPSs with increased risk of ASS or PTS should be further studied in larger groups of such patients.

Epigenetic mechanisms in learned fear: implications for PTSD

One of the most exciting discoveries in the learning and memory field in the past two decades is the observation that active regulation of gene expression is necessary for experience to trigger lasting functional and behavioral change, in a wide variety of species, including humans. Thus, as opposed to the traditional view of 'nature' (genes) being separate from 'nurture' (environment and experience), it is now clear that experience actively drives alterations in central nervous system (CNS) gene expression in an ongoing fashion, and that the resulting transcriptional changes are necessary for experience to trigger altered long-term behavior. In parallel over the past decade, epigenetic mechanisms, including regulation of chromatin structure and DNA methylation, have been shown to be potent regulators of gene transcription in the CNS. In this review, we describe data supporting the hypothesis that epigenetic molecular mechanisms, especially DNA methylation and demethylation, drive long-term behavioral change through active regulation of gene transcription in the CNS. Specifically, we propose that epigenetic molecular mechanisms underlie the formation and stabilization of context- and cue-triggered fear conditioning based in the hippocampus and amygdala, a conclusion reached in a wide variety of studies using laboratory animals. Given the relevance of cued and contextual fear conditioning to post-traumatic stress, by extension we propose that these mechanisms may contribute to post-traumatic stress disorder (PTSD) in humans. Moreover, we speculate that epigenetically based pharmacotherapy may provide a new avenue of drug treatment for PTSD-related cognitive and behavioral function.

Pavlovian fear memory circuits and phenotype models of PTSD

Pavlovian fear conditioning, also known as classical fear conditioning is an important model in the study of the neurobiology of normal and pathological fear. Progress in the neurobiology of Pavlovian fear also enhances our understanding of disorders such as posttraumatic stress disorder (PTSD) and with developing effective treatment strategies. Here we describe how Pavlovian fear conditioning is a key tool for understanding both the neurobiology of fear and the mechanisms underlying variations in fear memory strength observed across different phenotypes. First we discuss how Pavlovian fear models aspects of PTSD. Second, we describe the neural circuits of Pavlovian fear and the molecular mechanisms within these circuits that regulate fear memory. Finally, we show how fear memory strength is heritable; and describe genes which are specifically linked to both changes in Pavlovian fear behavior and to its underlying neural circuitry. These emerging data begin to define the essential genes, cells and circuits that contribute to normal and pathological fear. This article is part of a Special Issue entitled 'Post-Traumatic Stress Disorder'.