Eating Disorders and Epigenetics

The risk of eating disorders following the August 4th, 2020 explosion in Beirut and its relationship with trauma exposure and PTSD symptoms

INTRODUCTION

To date, no study has demonstrated the link between the diagnosis of provisional PTSD and ED in people exposed to the explosion of August 4th, 2020.

METHODS

Online participants were classified into 4 categories according to the degree of exposure to the explosion (unexposed, slightly exposed, moderately exposed, and severely exposed). The screening for ED was done using the standardized SCOFF questionnaire and the screening for provisional PTSD using the standardized IES-R questionnaire.

RESULTS

Our sample included 703 participants. In the bivariate analysis, there was a trend for an association between degree of exposure to the explosion and the risk of development of an ED (p = 0.055). The independent variables included in the multivariate analysis that were statistically associated with a risk of developing eating disorders are secondary school as the highest level of education (p = 0.029; OR = 2.15) and the risk of PTSD (p = 0.041; OR = 2.05) according to IES-R, specifically hyperarousal (p = 0.028; OR = 1.07) as a symptom cluster. Provisional PTSD played a mediating role, creating a partial and indirect relationship between the degree of exposure to the explosion and the risk of developing ED with a β coefficient of 0.075 (p < 0.001) CONCLUSION: The risk of PTSD according to IES-R was found to be a determinant of a higher risk of developing ED among participants exposed to the explosion in addition to mediating between the effect of exposure severity and the risk of ED. It is essential to fully assess and manage PTSD symptoms and ED patients exposed to such a psychological trauma.

Adverse childhood experiences, the risk of pregnancy complications and adverse pregnancy outcomes: a systematic review and meta-analysis

BACKGROUND

Adverse childhood experiences (ACEs) have a profound negative impact on health. However, the strength of the association between ACEs and pregnancy complications and adverse pregnancy outcomes is not well quantified or understood.

OBJECTIVE

To conduct a systematic review and meta-analysis of the association between ACEs and risk of pregnancy complications and adverse pregnancy outcomes.

SEARCH STRATEGY

A comprehensive search was conducted using PubMed, Embase, CINAHL, PsycINFO, ClinicalTrials.gov and Google scholar up to July 2022.

DATA COLLECTION AND ANALYSIS

Two reviewers independently conducted the screening and quality appraisal using a validated tool. Meta-analysis using the quality-effects model on the reported odds ratio (OR) was conducted. Heterogeneity and inconsistency were examined using the I2 statistics.

RESULTS

32 studies from 1508 met a priori inclusion criteria for systematic review, with 21 included in the meta-analysis. Pooled analyses showed that exposure to ACEs increased the risk of pregnancy complications (OR 1.37, 95% CI 1.20 to 1.57) and adverse pregnancy outcomes (OR 1.31, 95% CI 1.17 to 1.47). In sub-group analysis, maternal ACEs were associated with gestational diabetes mellitus (OR 1.39, 95% CI 1.11 to 1.74), antenatal depression (OR 1.59, 95% CI 1.15 to 2.20), low offspring birth weight (OR 1.27, 95% CI 1.02 to 1.47), and preterm delivery (OR 1.41, 95% CI 1.16 to 1.71).

CONCLUSION

The results suggest that exposure to ACEs increases the risk of pregnancy complications and adverse pregnancy outcomes. Preventive strategies, screening and trauma-informed care need to be examined to improve maternal and child health.

Mechanisms by which adverse childhood experiences, other traumas and PTSD influence the health and well-being of individuals with eating disorders throughout the life span

BACKGROUND

Multiple published sources from around the world have confirmed an association between an array of adverse childhood experiences (ACEs) and other traumatic events with eating disorders (EDs) and related adverse outcomes, including higher morbidity and mortality.

METHODS

In keeping with this Special Issue's goals, this narrative review focuses on the ACEs pyramid and its purported mechanisms through which child maltreatment and other forms of violence toward human beings influence the health and well-being of individuals who develop EDs throughout the life span. Relevant literature on posttraumatic stress disorder (PTSD) is highlighted when applicable.

RESULTS

At every level of the pyramid, it is shown that EDs interact with each of these proclaimed escalating mechanisms in a bidirectional manner that contributes to the predisposition, precipitation and perpetuation of EDs and related medical and psychiatric comorbidities, which then predispose to early death. The levels and their interactions that are discussed include the contribution of generational embodiment (genetics) and historical trauma (epigenetics), social conditions and local context, the ACEs and other traumas themselves, the resultant disrupted neurodevelopment, subsequent social, emotional and cognitive impairment, the adoption of health risk behaviors, and the development of disease, disability and social problems, all resulting in premature mortality by means of fatal complications and/or suicide.

CONCLUSIONS

The implications of these cascading, evolving, and intertwined perspectives have important implications for the assessment and treatment of EDs using trauma-informed care and trauma-focused integrated treatment approaches. This overview offers multiple opportunities at every level for the palliation and prevention of EDs and other associated trauma-related conditions, including PTSD.

A critical analysis of eating disorders and the gut microbiome

The gut microbiota, also known as our "second brain" is an exciting frontier of research across a multitude of health domains. Gut microbes have been implicated in feeding behaviour and obesity, as well as mental health disorders including anxiety and depression, however their role in the development and maintenance of eating disorders (EDs) has only recently been considered. EDs are complex mental health conditions, shaped by a complicated interplay of factors. Perhaps due to an incomplete understanding of the etiology of EDs, treatment remains inadequate with affected individuals likely to face many relapses. The gut microbiota may be a missing piece in understanding the etiology of eating disorders, however more robust scientific inquiry is needed in the field before concrete conclusions can be made. In this spotlight paper, we critically evaluate what is known about the bi-directional relationship between gut microbes and biological processes that are implicated in the development and maintenance of EDs, including physiological functioning, hormones, neurotransmitters, the central nervous system, and the immune system. We outline limitations of current research, propose concrete steps to move the field forward and, hypothesize potential clinical implications of this research. Our gut is inhabited by millions of bacteria which have more recently been referred to as "our second brain". In fact, these microbes are thought to play a role in ED behaviour, associated anxiety and depression, and even affect our weight. Recent research has dove into this field with promising findings that have the potential to be applied clinically to improve ED recovery. The present paper discusses what is known about the gut microbiome in relation to EDs and the promising implications that leveraging this knowledge, through fecal microbiome transplants, probiotics, and microbiome-directed supplemental foods, could have on ED treatment.

[Significance of DNA methylation assessment in the morphological diagnosis of brain tumours]

The review is focused on a relatively new research method in oncology - DNA methylation. Starting from the methylation of individual genes, the method is gradually expanding and becoming routine for studying the global structure of DNA methylation (methylome) in tumors of various localizations. For some tumors (carcinomas of the mammary and thyroid glands), the study of the global structure of DNA methylation is just beginning, while methylation classifiers have been proposed and successfully used in the Russian Federation for brain tumours and sarcomas. This article compares the fifth edition of the WHO Classification of tumours of the Central Neurvous System and the methylation brain classifier.

Adversity in childhood is linked to mental and physical health throughout life

The prevalence of “toxic stress” and huge downstream consequences in disease, suffering, and financial costs make prevention and early intervention crucial, say Charles A Nelson and colleagues

A review of binge eating disorder and obesity

Binge eating disorder (BED) is a mental illness characterised by recurrent binge eating episodes in the absence of appropriate compensatory behaviours. Consequently, BED is strongly associated with obesity. The current review aims to provide an update of the most relevant aspects of BED (e.g., clinical profile, aetiology and treatment approaches), in order not only to facilitate a better understanding of the disorder and its clinical consequences, but also to identify potential targets of prevention and intervention. Patients with BED often present high comorbidity with other medical conditions and psychiatric disorders. Numerous risk factors have been associated with the development and maintenance of the disorder. Moreover, although some treatments for BED have proven to be effective in addressing different key aspects of the disorder, the rates of patients that have ever received specific treatment for BED are very low. The factors involved and how to implement effective treatments will be discussed for the purpose of addressing the eating symptomatology and comorbid obesity.

Pre-clinical models of reward deficiency syndrome: A behavioral octopus

Individuals with mood disorders or with addiction, impulsivity and some personality disorders can share in common a dysfunction in how the brain perceives reward, where processing of natural endorphins or the response to exogenous dopamine stimulants is impaired. Reward Deficiency Syndrome (RDS) is a polygenic trait with implications that suggest cross-talk between different neurological systems that include the known reward pathway, neuroendocrine systems, and motivational systems. In this review we evaluate well-characterized animal models for their construct validity and as potential models for RDS. Animal models used to study substance use disorder, major depressive disorder (MDD), early life stress, immune dysregulation, attention deficit hyperactivity disorder (ADHD), post traumatic stress disorder (PTSD), compulsive gambling and compulsive eating disorders are discussed. These disorders recruit underlying reward deficiency mechanisms in multiple brain centers. Because of the widespread and remarkable array of associated/overlapping behavioral manifestations with a common root of hypodopaminergia, the basic endophenotype recognized as RDS is indeed likened to a behavioral octopus. We conclude this review with a look ahead on how these models can be used to investigate potential therapeutics that target the underlying common deficiency.

Behavioral Alterations in Mice Carrying Homozygous HDAC4 A778T Missense Mutation Associated With Eating Disorder

Eating disorders (EDs) are serious mental illnesses thought to arise from the complex gene-environment interactions. DNA methylation patterns in histone deacetylase 4 (HDAC4) locus have been associated with EDs and we have previously identified a missense mutation in the HDAC4 gene (HDAC4^A786T) that increases the risk of developing an ED. In order to evaluate the biological consequences of this variant and establish a useful mouse model of EDs, here we performed behavioral characterization of mice homozygous for Hdac4^A778T (corresponding to human HDAC4^A786T) that were further backcrossed onto C57BL/6 background. When fed high-fat diet, male, but not female, homozygous mice showed a trend toward decreased weight gain compared to their wild-type littermates. Behaviorally, male, but not female, homozygous mice spent less time in eating and exhibited reduced motivation to work for palatable food and light phase-specific decrease in locomotor activity. Additionally, homozygous Hdac4^A778T female, but not male, mice display social subordination when subjected to a tube dominance test. Collectively, these results reveal a complex sex- and circadian-dependent role of ED-associated Hdac4^A778T mutation in affecting mouse behaviors. Homozygous Hdac4^A778T mice could therefore be a useful animal model to gain insight into the neurobiological basis of EDs.

Histone deacetylase 4 (HDAC4): a new player in anorexia nervosa?

Anorexia nervosa (AN) and other eating disorders continue to constitute significant challenges for individual and public health. AN is thought to develop as a result of complex interactions between environmental triggers, psychological risk factors, sociocultural influences, and genetic vulnerability. Recent research developments have highlighted a novel potentially relevant component in the AN etiology-activity of the histone deacetylase 4 (HDAC4) gene that has emerged in several recent studies related to AN. HDAC4 is a member of the ubiquitously important family of epigenetic modifier enzymes called histone deacetylases and has been implicated in processes related to the formation and function of the central nervous system (CNS), bone, muscle, and metabolism. In a family affected by eating disorders, a missense mutation in HDAC4 (A786T) was found to segregate with the illness. The relevance of this mutation in eating-related behaviors was further confirmed with mouse models. Despite  the fact that HDAC4 has not been identified as a significant signal in genome-wide association studies in AN, several studies have found significant or near-significant methylation differences in HDAC4 locus in peripheral tissues of actively ill AN patients in comparison with different control groups. Limitations of these studies include a lack of understanding of to what extent the changes in methylation are predictive of AN as such changes might also occur as a consequence of the disease. It remains to be determined how methylation in peripheral tissues correlates with that in the CNS and how different methylation patterns affect HDAC4 expression. The present review discusses the findings and potential roles of HDAC4 in AN. Its emerging roles in learning and neuroplasticity may be specific and relevant for the etiology of AN and potentially lead to novel therapeutic approaches.

Association of Leptin Gene DNA Methylation With Diagnosis and Treatment Outcome of Anorexia Nervosa

Epigenetic alterations are increasingly implicated in the pathophysiology of anorexia nervosa (AN) but are as yet poorly understood. We investigated possible associations between the leptin gene (LEP) and the leptin receptor gene (LEPR) DNA promoter methylation and (1) a diagnosis of AN and (2) outcome after a 10 months psychotherapeutic outpatient treatment. 129 (LEPR: n = 135) patients with AN were investigated during the large scale psychotherapeutic Anorexia Nervosa Treatment Outpatient Study (ANTOP) trial, compared to 117 (LEPR: n = 119) age and height matched, normal-weight healthy controls. Blood samples were taken at baseline, the end of therapy (40 weeks) and the 12-months follow-up and compared to controls. Methylation was measured in whole blood via bisulfite sequencing. Within the promoter region 32 (LEP) and 39 CpG sites (LEPR) were analyzed. Two key findings were observed. First, LEP and LEPR methylation at baseline were lower in patients compared to controls (LEP: [%] AN: 30.94 ± 13.2 vs. controls: 34.53 ± 14.6); LEPR ([%] AN: 3.73 ± 5.4 vs. controls: 5.22 ± 8.3, mixed linear models: both P < 0.001). Second, lower DNA methylation of the LEP promoter, with a dynamic upregulation during treatment, was associated with a full recovery in AN patients (% change from baseline to follow-up in full recovery patients: +35.13% (SD: 47.56); mixed linear model: P < 0.0001). To test for potential predictive properties of mean LEP DNA methylation a LEP DNA methylation cut-off (31.25% DNA methylation) was calculated, which significantly discriminated full recovery vs. full syndrome AN patients. This cut-off was then tested in a group of previously unclassified patients (missing follow-up data of the Structured Interview for Anorexic and Bulimic disorders; n = 33). Patients below the cut-off (31.25% LEP DNA methylation) showed an increase in BMI over time, while those above the cut-off had a decrease in BMI (ANOVA at the 12-months follow-up: P = 0.0142). To our knowledge, this is the first study investigating epigenetic alterations in AN over time. Our findings indicate that LEP DNA methylation might be involved in the disease course of AN.

A study on the interplay between emerging adulthood and eating disorder symptomatology in young adults

PURPOSE

The primary aim of this study was to investigate the interplay between Arnett's five features of emerging adulthood and ED symptomatology. The secondary aim of the study was to investigate possible gender differences concerning the relation between emerging adulthood and ED symptomatology.

METHODS

337 university students (252 females and 85 males) participated in this study. Each participant was asked to anonymously complete the following questionnaires: Inventory of the Dimensions of Emerging Adulthood (IDEA), Eating Attitudes Test (EAT-26), and Social Physique Anxiety Scale (SPAS).

RESULTS

The female group scored higher in the EAT-26 diet, SPAS, IDEA self-focus and IDEA total score measurements. Additionally, in the female group, identity exploration was correlated with EAT-26 total and bulimia, experimentation/possibilities with EAT-26 total and diet, and negativity/instability with EAT-26 total, diet and bulimia as well as SPAS score. In the male groups, the only significant correlation was between SPAS and instability/negativity. Finally, identity exploration could predict a higher probability of developing ED (EAT ≥ 20) for both the female and male groups.

CONCLUSIONS

Emerging adulthood and ED were found to have a close relationship, especially for females. Identity exploration was the emerging adulthood factor that showed the highest relation to ED symptomatology in both the male and female groups. More research is necessary to investigate the specifics of this relationship.

LEVEL OF EVIDENCE

Level V, cross-sectional descriptive study.

Rigor and reproducibility in genetic research on eating disorders

OBJECTIVE

We explored both within-method and between-method rigor and reproducibility in the field of eating disorders genetics.

METHOD

We present critical evaluation and commentary on component methods of genetic research (family studies, twin studies, molecular genetic studies) and discuss both successful and unsuccessful efforts in the field.

RESULTS

Eating disorders genetics has had a number of robust results that converge across component methodologies. Familial aggregation of eating disorders, twin-based heritability estimates of eating disorders, and genome-wide association studies (GWAS) all point toward a substantial role for genetics in eating disorders etiology and support the premise that genes do not act alone. Candidate gene and linkage studies have been less informative historically.

DISCUSSION

The eating disorders field has entered the GWAS era with studies of anorexia nervosa. Continued growth of sample sizes is essential for rigorous discovery of actionable variation. Molecular genetic studies of bulimia nervosa, binge-eating disorder, and other eating disorders are virtually nonexistent and lag seriously behind other major psychiatric disorders. Expanded efforts are necessary to reveal the fundamental biology of eating disorders, inform clinical practice, and deliver new therapeutic targets.

Food Addiction and Binge Eating: Lessons Learned from Animal Models

The feeding process is required for basic life, influenced by environment cues and tightly regulated according to demands of the internal milieu by regulatory brain circuits. Although eating behaviour cannot be considered "addictive" under normal circumstances, people can become "addicted" to this behaviour, similarly to how some people are addicted to drugs. The symptoms, cravings and causes of "eating addiction" are remarkably similar to those experienced by drug addicts, and both drug-seeking behaviour as eating addiction share the same neural pathways. However, while the drug addiction process has been highly characterised, eating addiction is a nascent field. In fact, there is still a great controversy over the concept of "food addiction". This review aims to summarize the most relevant animal models of "eating addictive behaviour", emphasising binge eating disorder, that could help us to understand the neurobiological mechanisms hidden under this behaviour, and to improve the psychotherapy and pharmacological treatment in patients suffering from these pathologies.