Maternal Age at Holocaust Exposure and Maternal PTSD Independently Influence Urinary Cortisol Levels in Adult Offspring

Role of Epigenetic Modification in the Intergeneration Transmission of War Trauma

War trauma has been linked to changes in the neuroendocrine and immunological systems and increases the risk of physical disorders. Traumatic events during the war may have long-term repercussions on psychological and biological parameters in future generations, implying that traumatic stress may have transgenerational consequences. This article addresses how epigenetic mechanisms, which are a key biological mechanism for dynamic adaptation to environmental stressors, may help explain the long-term and transgenerational consequences of trauma. In war survivors, epigenetic changes in genes mediating the hypothalamus-pituitary-adrenal axis, as well as the immune system, have been reported. These genetic modifications may cause long-term changes in the stress response as well as physical health risks. Also, the finding of biomarkers for diagnosing the possibility of psychiatric illnesses in people exposed to stressful conditions such as war necessitates extensive research. While epigenetic research has the potential to further our understanding of the effects of trauma, the findings must be interpreted with caution because epigenetic molecular mechanisms is only one piece of a complicated puzzle of interwoven biological and environmental components.

DNA methylation in blood cells is associated with cortisol levels in offspring of mothers who had prenatal post‐traumatic stress disorder

Maternal stress during pregnancy is associated with differential DNA methylation in offspring and disrupted cortisol secretion. This study aimed to determine methylation signatures of cortisol levels in children, and whether associations differ based on maternal post-traumatic stress disorder (PTSD). Blood epigenome-wide methylation and fasting cortisol levels were measured in 118 offspring of mothers recruited from the Kosovo Rehabilitation Centre for Torture Victims. Mothers underwent clinically administered assessment for PTSD using Diagnostic and Statistical Manual of Mental Disorders. Correlations between offspring methylation and cortisol levels were examined using epigenome-wide analysis, adjusting for covariates. Subsequent analysis focussed on a priori selected genes involved in the hypothalamic-pituitary-adrenal (HPA) axis stress signalling. Methylation at four sites were correlated with cortisol levels (cg15321696, r = -0.33, cg18105800, r = +0.33, cg00986889, r = -0.25, and cg15920527, r = -0.27). In adjusted multivariable regression, when stratifying based on prenatal PTSD status, significant associations were only found for children born to mothers with prenatal PTSD (p < 0.001). Several sites within HPA axis genes were also associated with cortisol levels in the maternal PTSD group specifically. There is evidence that methylation is associated with cortisol levels, particularly in offspring born to mothers with prenatal PTSD. However, larger studies need to be carried out to independently validate these findings.

Germ Cell Drivers: Transmission of Preconception Stress Across Generations

Exposure to stress can accelerate maturation and hasten reproduction. Although potentially adaptive, the trade-off is higher risk for morbidity and mortality. In humans, the intergenerational effects of stress have been demonstrated, but the precise mechanisms are unknown. Strikingly, even if parental stress occurs prior to conception, as adults, their offspring show worse mental and physical health. Emerging evidence primarily from preclinical models suggests that epigenetic programming may encode preconception stress exposures in germ cells, potentially impacting the phenotype of the offspring. In this narrative review, we evaluate the strength of the evidence for this mechanism across animals and humans in both males and females. The strongest evidence comes from studies of male mice, in which paternal preconception stress is associated with a host of phenotypic changes in the offspring and stress-induced changes in the small non-coding RNA content in sperm have been implicated. Two recent studies in men provide evidence that some small non-coding RNAs in sperm are responsive to past and current stress, including some of the same ones identified in mice. Although preliminary evidence suggests that findings from mice may map onto men, the next steps will be (1) considering whether stress type, severity, duration, and developmental timing affect germ cell epigenetic markers, (2) determining whether germ cell epigenetic markers contribute to disease risk in the offspring of stress-exposed parents, and (3) overcoming methodological challenges in order to extend this research to females.

Update on the neurodevelopmental theory of depression: is there any 'unconscious code'?

Depression is currently one of the most common psychiatric disorders and the number of patients receiving antidepressant treatment is increasing every year. Therefore, it is essential to understand the underlying mechanisms that are associated with higher prevalence of depression. The main component leading to the change in functioning, in the form of apathy, anhedonia, lack of motivation and sleep disturbances, is stress. This is the factor that in recent decades—due to the civilization speed, dynamic technological development as well as competitiveness and competition in relationships—significantly affects the psychophysical condition, which results in an increase in the prevalence of civilization diseases, including depression. To understand the mechanism of susceptibility to this disease, one should consider the significant role of the interaction between immune and nervous systems. Their joint development from the moment of conception is a matrix of later predispositions, both associated with the mobilization of the proinflammatory pathways (TNFα, IL-1β, IL-6) and associated with psychological coping with stress. Such an early development period is associated with epigenetic processes that are strongly marked in prenatal development up to 1 year of age and determinate the characteristic phenotype for various forms of pathology, including depression. Regarding the inflammatory hypothesis of depression, interleukin 17 (IL-17), among other proinflammatory cytokines, might play an important role in the development of depressive disorders. It is secreted by Th17 cells, crossed the placental barrier and acts on the brain structures of the fetus by increasing IL-17 receptor levels and affecting the intensity of its signaling in the brain.

Hair Cortisol as a Marker of Intergenerational Heritage of War? A Study of Veterans and Their Offspring

OBJECTIVE

Posttraumatic stress disorder (PTSD) has been associated with lower circulating cortisol levels in specific subgroups, which have also been found in the offspring of people with PTSD. The analysis of hair cortisol concentrations (HCC) is a recent methodology which is used to assess long-term systemic cortisol levels. We aimed to study veterans with war-related lifetime PTSD and their respective offspring with regards to HCC. We also studied the influence of lifetime major depressive disorder (MDD), war experiences, and childhood adversities on HCC in these groups.

METHODS

31 male veterans with PTSD and 28 without PTSD and 69 adult offspring were studied. HCC were quantified by liquid chromatography tandem-mass spectrometry.

RESULTS

No differences in HCC were found between veterans with and without PTSD, or between their respective offspring. Veterans without MDD showed a positive association between total war exposure and HCC. Veterans reporting more frequent childhood physical abuse had lower HCC. Veterans-with-PTSD's offspring with MDD had increased HCC compared to offspring without MDD. Offspring's exposure to more frequent childhood physical abuse was negatively associated with HCC in those without MDD.

CONCLUSION

HCC did not appear to constitute a marker of intergenerational heritage of war-related PTSD, except in the case of veteranswith-PTSD's offspring with MDD. Our data suggest that HCC is a marker of adult reported childhood physical abuse.

Intergenerational Effects of Maternal Holocaust Exposure on FKBP5 Methylation

OBJECTIVE

There is growing evidence that exposure to trauma prior to conception can affect offspring. The authors have reported that adult offspring of Holocaust survivors showed lower methylation of FK506 binding protein 5 (FKBP5) intron 7, site 6 compared with Jewish comparison volunteers. The present study sought to replicate this finding in a larger sample and to examine parental and offspring correlates of observed effects.

METHODS

Cytosine methylation was measured in blood using pyrosequencing. The independent replication sample consisted of 125 Holocaust offspring and 31 control subjects. Additional analyses, performed in a larger sample of 147 offspring and 40 control subjects that included the 31 previously studied participants, examined associations of parental trauma-related variables (i.e., sex of the exposed parent, parental posttraumatic stress disorder, age at Holocaust exposure) and offspring characteristics (i.e., childhood trauma exposure, lifetime psychiatric diagnoses, psychotropic medication use, FKBP5 rs1360780 genotype, FKBP5 gene expression, and neuroendocrine measures) with offspring FKBP5 methylation.

RESULTS

FKBP5 site 6 methylation was significantly lower in Holocaust offspring than in control subjects, an effect associated with maternal Holocaust exposure in childhood and with lower offspring self-reported anxiety symptoms. FKBP5 gene expression was elevated in Holocaust offspring. FKBP5 methylation was associated with indices of glucocorticoid sensitivity but not with basal FKBP5 gene expression.

CONCLUSIONS

This study replicates and extends the previously observed decrement in FKBP5 intron 7, site 6 methylation in Holocaust offspring. The predominance of this effect in offspring of mothers exposed during childhood implicates maternal developmental programming as a putative mechanism.

Maternal early life maltreatment and psychopathology affect the next generation: Alterations in post-awakening cortisol levels of primary school-aged children

Early life maltreatment (ELM) has severe and lasting effects on the individual, which might also impact the next generation. On an endocrine level, the hypothalamus-pituitary-adrenal axis has been suggested to play an important role in the interplay between ELM and the development of mental disorders. Several studies have revealed that maternal post-awakening cortisol concentration, maternal sensitivity, maternal ELM and psychopathology are associated with children's cortisol levels. We investigated the post-awakening cortisol concentrations in 6- to 11-year-old children (N = 53) whose mothers either had experienced ELM and had developed a lifetime mental disorder (N = 15 ELM and disorder group), had experienced ELM without developing a mental disorder (N = 12 ELM-only group), or had neither experienced ELM nor developed a mental disorder (N = 26 HC-group). Furthermore, we assessed maternal post-awakening cortisol concentrations, maternal psychopathology, and sensitivity. Multilevel analysis revealed higher cortisol at awakening (S1) levels in children of mothers with ELM and disorder. Maternal cortisol at awakening (S1) also predicted the child's cortisol at awakening (S1), and no effect of maternal sensitivity could be found. The current results replicate an attunement of cortisol levels (S1) between mothers and children and suggest an association between the children's endocrine stress system and maternal factors such as ELM and psychopathology.

The 24-hour urinary cortisol in post-traumatic stress disorder: A meta-analysis

Objective

Previous studies found inconsistent results on the relationship between post-traumatic stress disorder (PTSD) and concentrations of 24-hour (24-h) urinary cortisol. This study performed a systematic review and meta-analysis to summarize previous findings on this relationship.

Methods

We searched in the databases of Web of Science, PubMed, Embase, and Psyc-ARTICLES for articles published before September 2018. We used the random-effects model with restricted maximum-likelihood estimator to synthesize the effect sizes by calculating the standardized mean difference (SMD) and assessing its significance.

Results

Six hundred and nineteen articles were identified from the preceding databases and 20 of them were included in the meta-analysis. Lower concentrations of 24-h urinary cortisol were observed in patients with PTSD when compared with the controls (SMD = -0.49, 95%CI [-0.91; -0.07], p = 0.02). Subgroup analysis revealed that the concentrations of 24-h urinary cortisol were lower in PTSD patients than in the controls for studies that included female participants or studies that included participants from the United States of America.

Conclusions

Overall, decreased levels of 24-h urinary cortisol were linked with the pathophysiology of PTSD. Nonetheless, more studies should be conducted to validate the molecular underpinnings of urine cortisol degeneration in PTSD.

Does epigenetic 'memory' of early-life stress predispose to chronic pain in later life? A potential role for the stress regulator FKBP5

Animal behaviours are affected not only by inherited genes but also by environmental experiences. For example, in both rats and humans, stressful early-life events such as being reared by an inattentive mother can leave a lasting trace and affect later stress response in adult life. This is owing to a chemical trace left on the chromatin attributed to so-called epigenetic mechanisms. Such an epigenetic trace often has consequences, sometimes long-lasting, on the functioning of our genes, thereby allowing individuals to rapidly adapt to a new environment. One gene under such epigenetic control is FKBP5, the gene that encodes the protein FKPB51, a crucial regulator of the stress axis and a significant driver of chronic pain states. In this article, we will discuss the possibility that exposure to stress could drive the susceptibly to chronic pain via epigenetic modifications of genes within the stress axis such as FKBP5. The possibility that such modifications, and therefore, the susceptibility to chronic pain, could be transmitted across generations in mammals and whether such mechanisms may be evolutionarily conserved across phyla will also be debated. This article is part of the Theo Murphy meeting issue 'Evolution of mechanisms and behaviour important for pain'.

Intergenerational consequences of the Holocaust on offspring mental health: a systematic review of associated factors and mechanisms

Exposure to war and violence has major consequences for society at large, detrimental impact on people's individual lives, and may also have intergenerational consequences. To gain more insight into these intergenerational consequences, research addressing the impact of the Holocaust on offspring is an important source of information. The aim of the current study was to systematically review the mechanisms of intergenerational consequences by summarizing characteristics in Holocaust survivors and their offspring suggested to impact the offspring's mental health. We focused on: 1) parental mental health problems, 2) (perceived) parenting and attachment quality, 3) family structure, especially parental Holocaust history, 4) additional stress and life events, and 5) psychophysiological processes of transmission. We identified 23 eligible studies published between 2000 and 2018. Only Holocaust survivor studies met the inclusion criteria. Various parent and child characteristics and their interaction were found to contribute to the development of psychological symptoms and biological and epigenetic variations. Parental mental health problems, perceived parenting, attachment quality, and parental gender appeared to be influential for the mental well-being of their offspring. In addition, having two survivor parents resulted in higher mental health problems compared to having one survivor parent. Also, there was evidence suggesting that Holocaust survivor offspring show a heightened vulnerability for stress, although this was only evident in the face of actual danger. Finally, the results also indicate intergenerational effects on offspring cortisol levels. Clinical and treatment implications are discussed.

Intergenerational transmission of trauma effects: putative role of epigenetic mechanisms

This paper reviews the research evidence concerning the intergenerational transmission of trauma effects and the possible role of epigenetic mechanisms in this transmission. Two broad categories of epigenetically mediated effects are highlighted. The first involves developmentally programmed effects. These can result from the influence of the offspring's early environmental exposures, including postnatal maternal care as well as in utero exposure reflecting maternal stress during pregnancy. The second includes epigenetic changes associated with a preconception trauma in parents that may affect the germline, and impact fetoplacental interactions. Several factors, such as sex-specific epigenetic effects following trauma exposure and parental developmental stage at the time of exposure, explain different effects of maternal and paternal trauma. The most compelling work to date has been done in animal models, where the opportunity for controlled designs enables clear interpretations of transmissible effects. Given the paucity of human studies and the methodological challenges in conducting such studies, it is not possible to attribute intergenerational effects in humans to a single set of biological or other determinants at this time. Elucidating the role of epigenetic mechanisms in intergenerational effects through prospective, multi-generational studies may ultimately yield a cogent understanding of how individual, cultural and societal experiences permeate our biology.

Cultural trauma and epigenetic inheritance

The question of whether and how the effects of cultural trauma can be transmitted intergenerationally from parents to offspring, or even to later generations, has evoked interest and controversy in academic and popular forums. Recent methodological advances have spurred investigations of potential epigenetic mechanisms for this inheritance, representing an exciting area of emergent research. Epigenetics has been described as the means through which environmental influences “get under the skin,” directing transcriptional activity and influencing the expression or suppression of genes. Over the past decade, this complex environment–biology interface has shown increasing promise as a potential pathway for the intergenerational transmission of the effects of trauma. This article reviews challenges facing research on cultural trauma, biological findings in trauma and posttraumatic stress disorder, and putative epigenetic mechanisms for transmission of trauma effects, including through social, intrauterine, and gametic pathways. Implications for transmission of cultural trauma effects are discussed, focused on the relevance of cultural narratives and the possibilities of resilience and adaptivity.

The public reception of putative epigenetic mechanisms in the transgenerational effects of trauma

There has been great interest in the possibility that effects of trauma might be passed from parent to offspring through epigenetic mechanisms. This topic has stimulated discussion and controversy in the scientific literature, the popular press, and culture at large. This article describes the initial observations that have led to recent examinations of epigenetic mechanisms in association with effects of parental trauma exposure on offspring. Epigenetic research in animals has provided models for how such effects might be transmitted. However, the attribution of any specific epigenetic mechanisms in human studies of offspring of trauma survivors is premature at this time. The article describes some of the ways in which initial epigenetic findings in the offspring of trauma survivors have been represented in the popular media. Reports have ranged from overly simplistic and sensationalistic claims to global dismissals. The authors discuss the importance of clarity in language when describing epigenetic findings for lay audiences, the need to emphasize the limitations as well as the promise of research on intergenerational transmission of trauma effects, and the importance of countering popular interpretations that imply a reductionist biological determinism. Scientists have an obligation to assist in translating important research findings and nascent avenues of research to the public. It is important to recognize the ways in which this research may unintentionally be received as supporting a narrative of permanent and significant damage in offspring, rather than contributing to discussions of potential resilience, adaptability, and mutability in biological systems affected by stress.

Effects of interpersonal violence-related post-traumatic stress disorder (PTSD) on mother and child diurnal cortisol rhythm and cortisol reactivity to a laboratory stressor involving separation

Women who have experienced interpersonal violence (IPV) are at a higher risk to develop posttraumatic stress disorder (PTSD), with dysregulation of the hypothalamic-pituitary-adrenal (HPA) axis and impaired social behavior. Previously, we had reported impaired maternal sensitivity and increased difficulty in identifying emotions (i.e. alexithymia) among IPV-PTSD mothers. One of the aims of the present study was to examine maternal IPV-PTSD salivary cortisol levels diurnally and reactive to their child's distress in relation to maternal alexithymia. Given that mother-child interaction during infancy and early childhood has important long-term consequences on the stress response system, toddlers' cortisol levels were assessed during the day and in response to a laboratory stressor. Mothers collected their own and their 12-48month-old toddlers' salivary samples at home three times: 30min after waking up, between 2-3pm and at bedtime. Moreover, mother-child dyads participated in a 120-min laboratory session, consisting of 3 phases: baseline, stress situation (involving mother-child separation and exposure to novelty) and a 60-min regulation phase. Compared to non-PTSD controls, IPV-PTSD mothers - but not their toddlers, had lower morning cortisol and higher bedtime cortisol levels. As expected, IPV-PTSD mothers and their children showed blunted cortisol reactivity to the laboratory stressor. Maternal cortisol levels were negatively correlated to difficulty in identifying emotions. Our data highlights PTSD-IPV-related alterations in the HPA system and its relevance to maternal behavior. Toddlers of IPV-PTSD mothers also showed an altered pattern of cortisol reactivity to stress that potentially may predispose them to later psychological disorders.

Elevated cortisol in healthy female adolescent offspring of mothers with posttraumatic stress disorder

Offspring with maternal PTSD are at increased risk of developing PTSD themselves. Alterations in the hypothalamic-pituitary-adrenal (HPA) axis may play a role and have been noted in offspring, although evidence is mostly from adult offspring with PTSD symptoms themselves. The present study of adolescent girls (N=472) and their mothers (n=18 with lifetime PTSD versus n=454 with no PTSD) sought to determine whether healthy, non-affected offspring of mothers with PTSD would exhibit altered HPA axis function. Saliva samples were collected from the adolescent girls at waking, 30min after waking, and 8 pm on 3 consecutive days. Offspring whose mothers were diagnosed with PTSD demonstrated higher cortisol awakening response (CAR; Cohen's d=0.58) and greater total cortisol output (Cohen's d=0.62). In this preliminary study, higher cortisol levels during adolescence among offspring of mothers with PTSD may index a vulnerability in these at-risk youth.

Site-specific methylation changes in the glucocorticoid receptor exon 1F promoter in relation to life adversity: systematic review of contributing factors

There has been recent interest in epigenetics in psychiatry since it offers a means of understanding how stressful life experiences, in interaction with the genotype, result in epigenetic changes that result in altered gene expression, ultimately affecting the risk for mental disorders. Many studies focused on methylation of the glucocorticoid receptor exon 1F promoter following an initial observation that changes in this region could be modulated by the environment. This review examines all published studies that have attempted to measure methylation in this region using different techniques, several tissue types, populations at different behavioral state and stages of development. Methodological issues have been raised with the aim of attempting to understand methylation quantification and site of action. We propose that it is useful to examine whether methylation at specific sites within the promoter region may be particularly relevant to psychiatric vulnerability to stress-related outcomes.