How Traumatic Experiences Leave Their Signature on the Genome: An Overview of Epigenetic Pathways in PTSD

MicroRNAs as biomarker and novel therapeutic target for posttraumatic stress disorder in Veterans

Posttraumatic stress disorder (PTSD) is a common psychiatric disorder for military Veterans, characterized by hyperarousal, intrusive thoughts, flashbacks, hypervigilance, and distress after experiencing traumatic events. Some of the known physiological effects of PTSD include hypothalamic-pituitary-adrenal (HPA)-axis imbalance, a cortical function resulting in neuronal deficit and changes in behavior. Moreover, excessive discharge of inflammatory molecules and a dysregulated immune system are implicated in the pathophysiology of PTSD. Due to complex nature of this disorder, the biological underpinnings of PTSD remain inexplicable. Investigating novel biomarkers to understanding the pathogenesis of PTSD may reflect the underlying molecular network for therapeutic use and treatment. Circulatory microRNAs (miRNAs) and exosomes are evolving biomarkers that have shown a key role in psychiatric and neurological disorders including PTSD. Given the unique nature of combat trauma, as well as evidence that a large portion of Veterans do not benefit from frontline treatments, focus on veterans specifically is warranted. In the present review, we delineate the identification and role of several miRNAs in PTSD among veterans. An association of miRNA with HPA-axis regulation through FKBP5, a key modulator in PTSD is discussed as an emerging molecule in psychiatric diseases. We conclude that miRNAs may be used as circulatory biomarker detection in Veterans with PTSD.

Gender Beneath the Skull: Agency, Trauma and Persisting Stereotypes in Neuroepigenetics

Epigenetics stands in a complex relationship to issues of sex and gender. As a scientific field, it has been heavily criticized for disproportionately targeting the maternal body and reproducing deterministic views of biological sex (Kenney and Müller, 2017; Lappé, 2018; Richardson et al., 2014). And yet, it also represents the culmination of a long tradition of engaging with developmental biology as a feminist cause, because of the dispersal of the supposed 'master code' of DNA among wider cellular, organismic and ecological contexts (Keller, 1988). In this paper, we explore a number of tensions at the intersection of sex, gender and trauma that are playing out in the emerging area of neuroepigenetics - a relatively new subfield of epigenetics specifically interested in environment-brain relations through epigenetic modifications in neurons. Using qualitative interviews with leading scientists, we explore how trauma is conceptualized in neuroepigenetics, paying attention to its gendered dimensions. We address a number of concerns raised by feminist STS researchers in regard to epigenetics, and illustrate why we believe close engagement with neuroepigenetic claims, and neuroepigenetic researchers themselves, is a crucial step for social scientists interested in questions of embodiment and trauma. We argue this for three reasons: (1) Neuroepigenetic studies are recognizing the agential capacities of biological materials such as genes, neurotransmitters and methyl groups, and how they influence memory formation; (2) Neuroepigenetic conceptions of trauma are yet to be robustly coupled with social and anthropological theories of violence (Eliot, 2021; Nelson, 2021; Walby, 2013); (3) In spite of the gendered assumptions we find in neuroepigenetics, there are fruitful spaces - through collaboration - to be conceptualizing gender beyond culture-biology and nature-nurture binaries (Lock and Nguyen, 2010). To borrow Gravlee's (2009: 51) phrase, we find reason for social scientists to consider how gender is not only constructed, but how it may "become biology" via epigenetic and other biological pathways. Ultimately, we argue that a robust epigenetic methodology is one which values the integrity of expertise outside its own field, and can have an open, not empty mind to cross-disciplinary dialogue.

Epigenetics of the developing and aging brain: Mechanisms that regulate onset and outcomes of brain reorganization

Brain development is a life-long process that encompasses several critical periods of transition, during which significant cognitive changes occur. Embryonic development, puberty, and reproductive senescence are all periods of transition that are hypersensitive to environmental factors. Rather than isolated episodes, each transition builds upon the last and is influenced by consequential changes that occur in the transition before it. Epigenetic marks, such as DNA methylation and histone modifications, provide mechanisms by which early events can influence development, cognition, and health outcomes. For example, parental environment influences imprinting patterns in gamete cells, which ultimately impacts gene expression in the embryo which may result in hypersensitivity to poor maternal nutrition during pregnancy, raising the risks for cognitive impairment later in life. This review explores how epigenetics induce and regulate critical periods, and also discusses how early environmental interactions prime a system towards a particular health outcome and influence susceptibility to disease or cognitive impairment throughout life.

Suppression, but not reappraisal, is associated with inflammation in trauma-exposed veterans

BACKGROUND

Emotion dysregulation can elicit inflammatory activity. The current study examined whether specific maladaptive and adaptive emotion regulation strategies were associated with inflammatory markers in trauma-exposed veterans, above and beyond PTSD.

METHODS

In a cohort study, 606 participants exposed to a Criterion A trauma and recruited from Veteran Health Administration facilities completed fasting blood draws, the Emotion Regulation Questionnaire, and the Clinician Administered PTSD Scale-IV. Inflammation was assessed with high sensitivity C-reactive protein (hsCRP), white blood cell count (WBC), and fibrinogen levels. An inflammation index was created by summing standardized log-transformed levels of the three biomarkers. Our primary linear regression models were adjusted for sex, age, race, education, income, creatinine, and PTSD.

RESULTS

Suppression, but not cognitive reappraisal, was significantly associated with higher levels of the inflammatory index (β = 0.14, p = 0.001). Parallel analyses for the individual inflammatory markers also showed suppression, but not reappraisal, was significantly associated with higher hsCRP (β = 0.11, p = 0.01), WBC (β = 0.11, p = 0.01), and fibrinogen (β = 0.10, p = 0.02).

CONCLUSIONS

Emotional suppression is related to elevated systemic inflammation independent of PTSD. Cognitive reappraisal is unrelated to inflammation. Findings suggest over-utilization of maladaptive, rather than under-utilization of adaptive, emotion regulation strategies may be associated with systemic inflammation in trauma-exposed veterans.

Trauma-informed care and practice for eating disorders: personal and professional perspectives of lived experiences

BACKGROUND

Learning about the life stories of patients who have experienced a severe eating disorder (ED), but also traumas that led to PTSD, dissociative disorders, and other comorbidities, has great value to clinicians in their efforts to deliver trauma-informed care (TIC). Many investigators have been researching and writing about these issues for years, and strong scientific evidence has emerged, indicating that trauma is a significant risk factor for the development of EDs, particularly in its bulimic forms.

PURPOSE

Peer-reviewed literature contains scarce input from people with "lived experiences". Hearing and "sitting with" such individuals are extremely useful in clinical practice and research. Further, encouraging patients to put words to their pain has recognized therapeutic effects. These lived experiences are often demonstrative of key elements of what professionals need to know about evaluating and treating patients with EDs and co-occurring trauma-related disorders.

METHOD/RESULTS

The principal author invited two courageous recovered ED advocates and writers (June Alexander and Jenni Schaefer), who have gone public about their ED-PTSD experiences, to recount their life stories and treatment experiences (both positive and negative). Dr. Brewerton then offers his professional perspectives on the course of their treatment experiences put in the context of ongoing relevant clinical research.

CONCLUSION

Their and other patients' experiences have great power to guide professionals toward trauma-informed care, more integrated practice, and theoretically improved outcomes.

LEVEL OF EVIDENCE

Level V.

FGF21 regulates insulin sensitivity following long-term chronic stress

Objective

Post-traumatic stress disorder (PTSD) increases type 2 diabetes risk, yet the underlying mechanisms are unclear. We investigated how early-life exposure to chronic stress affects long-term insulin sensitivity.

Methods

C57Bl/6J mice were exposed to chronic variable stress for 15 days (Cvs) and then recovered for three months without stress (Cvs3m).

Results

Cvs mice showed markedly increased plasma corticosterone and hepatic insulin resistance. Cvs3m mice exhibited improved whole-body insulin sensitivity along with enhanced adipose glucose uptake and skeletal muscle mitochondrial function and fatty acid oxidation. Plasma FGF21 levels were substantially increased and associated with expression of genes involved in fatty acid oxidation and formation of brown-like adipocytes. In humans, serum FGF21 levels were associated with stress coping long time after the exposure.

Conclusions

Early-life exposure to chronic stress leads to long term improvements in insulin sensitivity, oxidative metabolism and adipose tissue remodeling. FGF21 contributes to a physiological memory mechanism to maintain metabolic homeostasis.

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Early-life exposure of mice to stress (CVS) causes acute insulin resistance but improves long-term insulin sensitivity.

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3 months after stress, mice had enhanced adipose glucose uptake and higher skeletal muscle mitochondrial function.

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Plasma FGF21 and gene expression for formation of brown-like adipocytes were substantially increased long after stress.

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In humans, serum FGF21 levels were associated with the ability to cope with stress long time after the exposure.