Perinatal depression and DNA methylation of oxytocin-related genes: a study of mothers and their children

A history of depression and prenatal depression are associated with a lower likelihood of breastfeeding initiation and maintenance, and more breastfeeding problems

PURPOSE

This study tests the hypotheses that lifetime history of depression, and prenatal depression, are associated with a reduced likelihood of breastfeeding initiation (giving the baby any breastmilk during the first week of life) and breastfeeding maintenance (giving the baby breastmilk for at least 6 months), and a greater likelihood of reporting breastfeeding problems.

METHODS

We analyzed data from the Norwegian Mother, Father, and Child cohort study (MoBa), N = 78,307. Mothers reported a lifetime history of depression during the second trimester of pregnancy, and current symptoms of depression during the third trimester using the Hopkins Symptoms Checklist short version (SCL-8). At six months postpartum, mothers self-reported breastfeeding initiation, maintenance, and difficulties.

RESULTS

Using binary logistic regression analyses, we report that a lifetime history of depression is associated with a lower likelihood of breastfeeding initiation (OR = 0.751, 95%CI = 0.650-0.938), breastfeeding maintenance (OR = 0.712, 95%CI = 0.669-0.785), and a greater likelihood of breastfeeding difficulties (OR = 1.86, 95%CI = 1.72-2.06). Similarly, prenatal depression was associated with a lower likelihood of breastfeeding initiation (OR = 0.904, 95%CI = 0.878-0.929), breastfeeding maintenance (OR = 0.929, 95%CI = 0.920-0.938), and a greater likelihood of breastfeeding difficulties (OR = 1.10, 95%CI = 1.09-1.12). Results remained largely unchanged when covaried for several confounding variables, including medication use.

CONCLUSION

We provide novel evidence that pre-conception and prenatal symptoms of depression are associated with breastfeeding outcomes. This information could be used to identify women very early in pregnancy who may need additional support with breastfeeding. There is also a need to fully understand the biopsychosocial mechanisms that mediate the relationship between depression prior to birth and breastfeeding outcomes.

The impact of the early environment on oxytocin receptor epigenetics and potential therapeutic implications

Oxytocin research is rapidly evolving and increasingly reveals that epigenetic modifications to the oxytocin receptor gene (OXTR) are functional, plastic, and reliable components of oxytocinergic system function. This review outlines how OXTR epigenetics are shaped by the early life environment, impact social-developmental outcomes, and have strong potential to serve as therapeutic targets. We first establish the malleability of OXTR epigenetics in infancy in both animal models and humans through research demonstrating the impact of the early life environment on OXTR DNA methylation (OXTRm) and subsequent social behavior. Next, we detail how OXTRm serves as a predictive mechanism for neurodevelopmental outcomes in animal models of social behavior such as the prairie vole, and summarize the role of OXTRm in psychiatric disorders, emotional processing, and attachment behavior in humans. We discuss the potential of further OXTRm research to improve oxytocin therapeutics by highlighting how a deeper knowledge of OXTRm could improve the therapeutic potential of exogenous oxytocin, how OXTRm may impact additional cellular mechanisms with therapeutic potential including control of the perinatal GABA switch, and how early life therapies may target the tuning of endogenous OXTRm. Finally, we review limitations of previous oxytocin research and make recommendations for future research. IMPACT: Previous research into oxytocin therapeutics has been hampered by methodological difficulties that may be improved by assay of the oxytocin receptor gene (OXTR) and its methylation (OXTRm) Key sites of OXTRm modification link early life exposures to developmental and behavioral outcomes OXTRm appears to have a critical period of development in early life Epigenetic modification of the oxytocin receptor gene could serve as a powerful target for therapeutic interventions.

Role of sexually dimorphic oxytocin receptor-expressing neurons in the anteroventral periventricular nucleus on maternal behavior

Oxytocin is a neuropeptide produced by magnocellular neurosecretory neurons located primarily in the supraoptic nucleus and paraventricular nucleus of the hypothalamus. The long axons of these neurons project to the neurohypophysis where oxytocin is released into the general circulation in response to the physiological demands. Oxytocin plays critical roles in female reproductive physiology, specifically in uterine contraction during labor and milk ejection while nursing. Oxytocin is also called "the love hormone" due to its modulatory roles in prosocial behaviors, including social recognition, maternal behavior, and pair bonding. Oxytocin influences behaviors by binding to oxytocin receptors (OXTR) located in various parts of the brain. Previously, we discovered a group of estrogen-dependent OXTR neurons that is exclusively present in the anteroventral periventricular nucleus (AVPV) of females but not of males. The female-specific expression of OXTR in the AVPV is a rare case of neurochemically-demonstrated, all-or-none sexual dimorphism in the brain. In this review, the cellular characterization and functional significance of the sexually dimorphic OXTR neurons in the AVPV as well as the clinical implications of the research will be discussed.

Epigenetic mechanisms in depression: Implications for pathogenesis and treatment

The risk of depression is influenced by both genetic and environmental factors. It has been suggested that epigenetic mechanisms may mediate the risk of depression following exposure to adverse life events. Epigenetics encompasses stable alterations in gene expression that are controlled through transcriptional, post-transcriptional, translational, or post-translational processes, including DNA modifications, chromatin remodeling, histone modifications, RNA modifications, and non-coding RNA (ncRNA) regulation, without any changes in the DNA sequence. In this review, we explore recent research advancements in the realm of epigenetics concerning depression. Furthermore, we evaluate the potential of epigenetic changes as diagnostic and therapeutic biomarkers for depression.

Social zebrafish: Danio rerio as an emerging model in social neuroendocrinology

The fitness benefits of social life depend on the ability of animals to affiliate with others and form groups, on dominance hierarchies within groups that determine resource distribution, and on cognitive capacities for recognition, learning and information transfer. The evolution of these phenotypes is coupled with that of neuroendocrine mechanisms, but the causal link between the two remains underexplored. Growing evidence from our research group and others demonstrates that the tools available in zebrafish, Danio rerio, can markedly facilitate progress in this field. Here, we review this evidence and provide a synthesis of the state-of-the-art in this model system. We discuss the involvement of generalized motivation and cognitive components, neuroplasticity and functional connectivity across social decision-making brain areas, and how these are modulated chiefly by the oxytocin-vasopressin neuroendocrine system, but also by reward-pathway monoamine signaling and the effects of sex-hormones and stress physiology.

The DNA methylation landscape of the human oxytocin receptor gene (OXTR): data-driven clusters and their relation to gene expression and childhood adversity

The oxytocin receptor gene (OXTR) is of interest when investigating the effects of early adversity on DNA methylation. However, there is heterogeneity regarding the selection of the most promising CpG sites to target for analyses. The goal of this study was to determine functionally relevant clusters of CpG sites within the OXTR CpG island in 113 mother-infant dyads, with 58 of the mothers reporting childhood maltreatment (CM). OXTR DNA methylation was analyzed in peripheral/umbilical blood mononuclear cells. Different complexity reduction approaches were used to reduce the 188 CpG sites into clusters of co-methylated sites. Furthermore, associations between OXTR DNA methylation (cluster- and site-specific level) and OXTR gene expression and CM were investigated in mothers. Results showed that, first, CpG sections differed strongly regarding their statistical utility for research of individual differences in DNA methylation. Second, cluster analyses and Partial Least Squares (PLS) suggested two clusters consisting of intron1/exon2 and the protein-coding region of exon3, respectively, as most strongly associated with outcome measures. Third, cross-validated PLS regression explained 7% of variance in CM, with low cross-validated variance explained for the prediction of gene expression. Fourth, substantial mother-child correspondence was observed in correlation patterns within the identified clusters, but only modest correspondence outside these clusters. This study makes an important contribution to the mapping of the DNA methylation landscape of the OXTR CpG island by highlighting clusters of CpG sites that show desirable statistical properties and predictive value. We provide a Companion Web Application to facilitate the choice of CpG sites.

Postpartum depression: aetiology, pathogenesis and the role of nutrients and dietary supplements in prevention and management

Postpartum depression (PPD) is a challenging psychological disorder faced by 10-30% of mothers across the globe. In India, it occurs among 22% of mothers. Its aetiology and pathophysiology aren't fully understood as of today but multiple theories on the interplay of hormones, neurotransmitters, genetics, epigenetics, nutrients, socio-environmental factors, etc. exist. Nutrients are not only essential for the synthesis of neurotransmitters, but they may also indirectly influence genomic pathways that methylate DNA, and there is evidence for molecular associations between nutritional quality and psychological well-being. Increased behavioural disorders have been attributed to macro- and micronutrient deficiencies, and dietary supplementation has been effective in treating several neuropsychiatric illnesses. Nutritional deficiencies occur frequently in women, especially during pregnancy and breastfeeding. The aim of this study was to perform a comprehensive literature review of evidence-based research in order to identify, gather and summarize existing knowledge on PPD's aetiology, pathophysiology, and the role of nutrients in its prevention as well as management. The possible mechanisms of action of nutrients are also presented here. Study findings show that the risk of depression increases when omega-3 fatty acid levels are low. Both fish oil and folic acid supplements have been used to effectively treat depression. Antidepressant efficacy is lowered by folate insufficiency. Folate, vitamin B12, iron, etc. deficiencies are more prevalent in depressed people than in non-depressed people. Serum cholesterol levels and plasma tryptophan levels are found to be inversely correlated with PPD. Serum vitamin D levels were associated inversely with perinatal depression. These findings highlight the importance of adequate nutrition in the antepartum period. Given that nutritional therapies can be affordable, safe, simple to use, and are typically well-accepted by patients, more focus should be placed on dietary variables in PPD.

Neonatal Care Unit Interventions on Preterm Development

Prematurity is becoming a real public health issue as more and more children are being born prematurely, alongside a higher prevalence of neurodevelopmental disorders. Early intervention programs in Neonatal Intensive Care Units (NICUs) correspond to these uni- or multi-sensorial solicitations aiming to prevent and detect complications in order to support the development of preterm infants. This article aims to distinguish sensory intervention programs according to the gradient of the type of solicitations, uni- or multi-modal, and according to the function of the person who performs these interventions. Uni-sensorial interventions are essentially based on proprioceptive, gustatory, or odorant solicitations. They allow, in particular, a reduction of apneas that support the vegetative states of the preterm infant. On the other hand, the benefits of multi-sensory interventions seem to have a longer-term impact. Most of them allow the support of the transition from passive to active feeding, an increase in weight, and the improvement of sleep-wake cycles. These solicitations are often practiced by caregivers, but the intervention of parents appears optimal since they are the main co-regulators of their preterm child's needs. Thus, it is necessary to co-construct and train the parents in this neonatal care.

DNA methylation in regulatory elements of the FKBP5 and NR3C1 gene in mother-child binomials with depression

BACKGROUND

The FKBP5 and NR3C1 genes play an important role in stress response, thus impacting mental health. Stress factor exposure in early life, such as maternal depression, may contribute to epigenetic modifications in stress response genes, increasing the susceptibility to different psychopathologies. The present study aimed to evaluate the DNA methylation profile in maternal-infant depression in regulatory regions of the FKBP5 gene and the alternative promoter of the NR3C1 gene.

METHODS

We evaluated 60 mother-infant pairs. The levels of DNA methylation were analyzed by the MSRED-qPCR technique.

RESULTS

We observed an increased DNA methylation profile in the NR3C1 gene promoter in children with depression and children exposed to maternal depression (p < 0.05). In addition, we observed a correlation of DNA methylation between mothers and offspring exposed to maternal depression. This correlation shows a possible intergenerational effect of maternal MDD exposure on the offspring. For FKBP5, we found a decrease in DNA methylation at intron 7 in children exposed to maternal MDD during pregnancy and a correlation of DNA methylation between mothers and children exposed to maternal MDD (p < 0.05).

LIMITATIONS

Although the individuals of this study are a rare group, the sample size of the study was small, and we evaluated the DNA methylation of only one CpG site for each region.

CONCLUSION

These results indicate changes in DNA methylation levels in regulatory regions of FKBP5 and NR3C1 in the mother-child MDD context and represent a potential target of studies to understand the depression etiology and how it occurs between generations.

Protective Role and Functional Engineering of Neuropeptides in Depression and Anxiety: An Overview

Behavioral disorders, such as anxiety and depression, are prevalent globally and touch children and adults on a regular basis. Therefore, it is critical to comprehend how these disorders are affected. It has been demonstrated that neuropeptides can influence behavior, emotional reactions, and behavioral disorders. This review highlights the majority of the findings demonstrating neuropeptides' behavioral role and functional engineering in depression and anxiety. Gut-brain peptides, hypothalamic releasing hormone peptides, opioid peptides, and pituitary hormone peptides are the four major groups of neuropeptides discussed. Some neuropeptides appear to promote depression and anxiety-like symptoms, whereas others seem to reduce it, all depending on the receptors they are acting on and on the brain region they are localized in. The data supplied here are an excellent starting point for future therapy interventions aimed at treating anxiety and depression.

Roles of the Oxytocin Receptor (OXTR) in Human Diseases

The oxytocin receptor (OXTR), encoded by the OXTR gene, is responsible for the signal transduction after binding its ligand, oxytocin. Although this signaling is primarily involved in controlling maternal behavior, it was demonstrated that OXTR also plays a role in the development of the nervous system. Therefore, it is not a surprise that both the ligand and the receptor are involved in the modulation of behaviors, especially those related to sexual, social, and stress-induced activities. As in the case of every regulatory system, any disturbances in the structures or functions of oxytocin and OXTR may lead to the development or modulation of various diseases related to the regulated functions, which in this case include either mental problems (autism, depression, schizophrenia, obsessive-compulsive disorders) or those related to the functioning of reproductive organs (endometriosis, uterine adenomyosis, premature birth). Nevertheless, OXTR abnormalities are also connected to other diseases, including cancer, cardiac disorders, osteoporosis, and obesity. Recent reports indicated that the changes in the levels of OXTR and the formation of its aggregates may influence the course of some inherited metabolic diseases, such as mucopolysaccharidoses. In this review, the involvement of OXTR dysfunctions and OXTR polymorphisms in the development of different diseases is summarized and discussed. The analysis of published results led us to suggest that changes in OXTR expression and OXTR abundance and activity are not specific to individual diseases, but rather they influence processes (mostly related to behavioral changes) that might modulate the course of various disorders. Moreover, a possible explanation of the discrepancies in the published results of effects of the OXTR gene polymorphisms and methylation on different diseases is proposed.

Foreign Nationality, Family Psychiatry History and Pregestational Neoplastic Disease as Predictors of Perinatal Depression in a Cohort of Healthy Pregnant and Puerperal Women during the COVID-19 Pandemic

Background: Perinatal depression (PND) represents one of the most common mental disorders in the pregnancy and/or postpartum period, with a 5-25% prevalence rate. Our aim was to investigate predictors associated with PND in a cohort of pregnant and puerperal women based in an Italian setting during the COVID-19 pandemic. Methods: We retrospectively recruited 199 (55 pregnant and 144 puerperal) women, afferent to our Perinatal Mental Outpatient Service of Ancona (Italy). Participants were administered an ad hoc case-report form, Whooley Questions (WQ), the General Health Questionnaire-12 (GHQ-12), the Stress Holmes-Rahe scale (HR) and the Edinburgh Postnatal Depression Scale (EPDS). Results: Around 10% of the sample had a confirmed PND. Being a foreigner woman (RR = 3.8), having a positive psychiatric family history (RR = 5.3), a pre-pregnancy medical comorbidity (RR = 1.85) and a comorbid medical illness occurring during the pregnancy (RR = 2) were much likely associated with PND. Multiple linear regression analysis demonstrated that GHQ, medium- and high-risk at the HR, foreign nationality, positive family psychiatric history, and neoplastic disease before conception significantly predicted EPDS [F(1, 197) = 10.086, R2 = 0.324, p < 0.001]. Limitations: The sample size, poor heterogeneity in terms of socio-demographic, clinical and gynecological-obstetric characteristics, the cross-sectional design of the study. Conclusions: Our study showed a set of predictors associated with a higher risk for the PND onset, including gestational and pregestational medical disease. Our findings outline the need to screen all fertile women, particularly in gynecological and medical settings, in order to identify at-risk women for PND and promptly suggest a psychiatric consultation.

Maternal distress, DNA methylation, and fetal programing of stress physiology in Brazilian mother-infant pairs

Maternal prenatal psychosocial stress is associated with adverse hypothalamic-pituitary-adrenal axis (HPAA) function among infants. Although the biological mechanisms influencing this process remain unknown, altered DNA methylation is considered to be one potential mechanism. We investigated associations between maternal prenatal psychological distress, infant salivary DNA methylation, and stress physiology at 12 months. Mother's distress was measured via depression and anxiety in early and late pregnancy in a cohort of 80 pregnant adolescents. Maternal hair cortisol was collected during pregnancy. Saliva samples were collected from infants at 12 months to quantify DNA methylation of three stress-related genes (FKBP5, NR3C1, OXTR) (n = 62) and diurnal cortisol (n = 29). Multivariable linear regression was used to test for associations between prenatal psychological distress, and infant DNA methylation and cortisol. Hair cortisol concentrations in late pregnancy were negatively associated with two sites of FKBP5 (site 1: B = -22.33, p = .003; site 2: B = -15.60, p = .012). Infants of mothers with elevated anxiety symptoms in late pregnancy had lower levels of OXTR2 CpG2 methylation (B = -2.17, p = .03) and higher evening salivary cortisol (B = 0.41, p = .03). Furthermore, OXTR2 methylation was inversely associated with evening cortisol (B = -0.14, p-value ≤ .001). Our results are, to our knowledge, the first evidence that the methylation of the oxytocin receptor may contribute to the regulation of HPAA during infancy.

DNA Methylation in Depression and Depressive-Like Phenotype: Biomarker or Target of Pharmacological Intervention?

Major depressive disorder (MDD) is a debilitating psychiatric disorder, the third leading global cause of disability. Regarding aetiopathogenetic mechanisms involved in the onset of depressive disorders, the interaction between genetic vulnerability traits and environmental factors is believed to play a major role. Although much is still to be elucidated about the mechanisms through which the environment can interact with genetic background shaping the disease risk, there is a general agreement about a key role of epigenetic marking. In this narrative review, we focused on the association between changes in DNA methylation patterns and MDD or depressive-like phenotype in animal models, as well as mechanisms of response to antidepressant drugs. We discussed studies presenting DNA methylation changes at specific genes of interest and profiling analyses in both patients and animal models of depression. Overall, we collected evidence showing that DNA methylation could not only be considered as a promising epigenetic biomarker of pathology but could also help in predicting antidepressant treatment efficacy. Finally, we discussed the hypothesis that specific changes in DNA methylation signature could play a role in aetiopathogenetic processes as well as in the induction of antidepressant effect.

OXTRHigh stroma fibroblasts control the invasion pattern of oral squamous cell carcinoma via ERK5 signaling

The Pattern Of Invasion (POI) of tumor cells into adjacent normal tissues clinically predicts postoperative tumor metastasis/recurrence of early oral squamous cell carcinoma (OSCC), but the mechanisms underlying the development of these subtypes remain unclear. Focusing on the highest score of POIs (Worst POI, WPOI) present within each tumor, we observe a disease progression-driven shift of WPOI towards the high-risk type 4/5, associated with a mesenchymal phenotype in advanced OSCC. WPOI 4-5-derived cancer-associated fibroblasts (CAFs^WPOI4-5), characterized by high oxytocin receptor expression (OXTR^High), contribute to local-regional metastasis. OXTR^High CAFs induce a desmoplastic stroma and CCL26 is required for the invasive phenotype of CCR3⁺ tumors. Mechanistically, OXTR activates nuclear ERK5 transcription signaling via Gαq and CDC37 to maintain high levels of OXTR and CCL26. ERK5 ablation reprograms the pro-invasive phenotype of OXTR^High CAFs. Therefore, targeting ERK5 signaling in OXTR^High CAFs is a potential therapeutic strategy for OSCC patients with WPOI 4-5.

Worst pattern of invasion (WPOI) is a parameter used to quantify tumor invasiveness of oral squamous cell carcinoma (OSCC). Here the authors show that a fibroblast subset characterized by the expression of the oxytocin receptor is enriched in highly invasive WPOI 4-5 OSCC tumors and can be targeted to reduce the desmoplastic stroma and tumor metastasis.

The shared mother-child epigenetic signature of neglect is related to maternal adverse events

Studies of DNA methylation have revealed the biological mechanisms by which life adversity confers risk for later physical and mental health problems. What remains unknown is the “biologically embedding” of maternal adverse experiences resulting in maladaptive parenting and whether these epigenetic effects are transmitted to the next generation. This study focuses on neglectful mothering indexed by a severe disregard for the basic and psychological needs of the child. Using the Illumina Human Methylation EPIC BeadChip in saliva samples, we identified genes with differentially methylated regions (DMRs) in those mothers with (n = 51), versus those without (n = 87), neglectful behavior that present similar DMRs patterns in their children being neglected versus non-neglected (n = 40 vs. 75). Mothers reported the emotional intensity of adverse life events. After covariate adjustment and multiple testing corrections, we identified 69 DMRs in the mother epigenome and 42 DMRs in the child epigenome that were simultaneously above the α = 0.01 threshold. The common set of nine DMRs contained genes related to childhood adversity, neonatal and infant diabetes, child neurobehavioral development and other health problems such as obesity, hypertension, cancer, posttraumatic stress, and the Alzheimer’s disease; four of the genes were associated with maternal life adversity. Identifying a shared epigenetic signature of neglect linked to maternal life adversity is an essential step in breaking the intergenerational transmission of one of the most common forms of childhood maltreatment.

Possible oxytocin-related biomarkers in anxiety and mood disorders

Anxiety and mood disorders are prevalent, disabling, and frequently difficult to treat. Such disorders are often comorbid and share similar characteristics. For more accurate diagnosis and improved treatment, a deeper understanding of the pathophysiology of anxiety and mood disorders is important. Oxytocin, a neuropeptide synthesized in the hypothalamus, affects human psychology and behaviors such as social and affiliative behaviors, fear and emotion processing, and stress regulation. Thus, oxytocin is believed to exert anxiolytic and antidepressant-like effects. This review article provides an overview of clinical studies on relationships between the oxytocin system and anxiety and mood disorders, focusing on oxytocin-related biomarker findings. Biomarkers used in such studies include central and peripheral oxytocin levels, analysis of oxytocin-related genes, and expression levels of oxytocin and oxytocin receptor genes in postmortem brains. Although a growing number of studies support the presence of oxytocinergic effects on anxiety and mood disorders, study results are heterogeneous and inconclusive. Moderating factors such as the characteristics of study populations, including sex, age, context, early life adversity, and attachment styles in patient cohorts, might affect the heterogeneity of the study results. Limitations in existing research such as small sample sizes, large dependence on peripheral sources of oxytocin, and inconsistent results between immunoassay methods complicate the interpretation of existing findings.

Dysfunctions of brain oxytocin signaling: Implications for poor mothering

Good mothering has profound impact on both the mother's and the young's well-being. Consequently, experiencing inadequate maternal care - or even neglect - in the first stages of life is a major risk factor for the development of psychiatric disorders, and even for poor parenting towards the future offspring. Thus, understanding the neurobiological basis of maternal neglect becomes crucial. Along with other neurotransmitters and neuropeptides, oxytocin (OXT) has long been known as one of the main modulators of maternal behavior. In rodents, disruptions of central OXT transmission have been associated with poor maternal responses, like impaired onset of nursing behaviors, and reduced care and defense of the pups. Importantly, such behavioral and molecular deficits can be transmitted through generations, creating a vicious circle of low-quality maternal behavior. Similarly, evidence from human studies shows that OXT signaling is defective in conditions of inadequate mothering and child neglect. On those premises, this review aims at providing a comprehensive overview of animal and human studies linking perturbed OXT transmission to poor maternal behavior. Considering the important fallouts of inadequate maternal responses, we believe that unraveling the alterations in OXT transmission might provide useful insights for a better understanding of maternal neglect and, ultimately, for future intervention approaches.

Love and longevity: A Social Dependency Hypothesis

Mammals, including humans, are reliant for survival and reproduction on adaptations associated with sociality and physiological investment, which can be linked to interactions with their parents or other bonded adult conspecifics. A wide range of evidence in human and non-human mammal species links social behaviors and relationships - including those characterized by what humans call "love" - to positive health and longevity. In light of this evidence, we propose a Social Dependency Hypothesis of Longevity, suggesting that natural selection has favored longer and healthier adult lives in species or in individuals exhibiting enhanced caregiver responsibilities contributing to the success of the next generation. In highlighting cellular, physiological, and behavioral effects of mammalian reproductive hormones, we examine the specific hypothesis that the neuropeptide oxytocin links longevity to the benefits of parental investment and associated relationships. Oxytocin is a pleiotropic molecule with anti-oxidant and anti-inflammatory properties, capable of regulating the hypothalamic-pituitary-adrenal axis, the parasympathetic nervous system and other systems associated with the management of various challenges, including chronic diseases and therefore may be crucial to establishing the maximum longevity potential of a species or an individual.

DNA methylation in stress and depression: from biomarker to therapeutics

Epigenetic mechanisms such as DNA methylation (DNAm) have been associated with stress responses and increased vulnerability to depression. Abnormal DNAm is observed in stressed animals and depressed individuals. Antidepressant treatment modulates DNAm levels and regulates gene expression in diverse tissues, including the brain and the blood. Therefore, DNAm could be a potential therapeutic target in depression. Here, we reviewed the current knowledge about the involvement of DNAm in the behavioural and molecular changes associated with stress exposure and depression. We also evaluated the possible use of DNAm changes as biomarkers of depression. Finally, we discussed current knowledge limitations and future perspectives.

The Methylation of Clock Genes in Perinatal Depression: Which Role for Oxytocin?

Background: Perinatal Depression (PD) is a widespread disabling condition that is hypothesized to be associated with abnormalities in circadian rhythms and neuropeptide release including oxytocin (OXT). Methods: Fourty-four pregnant women (28 with PD, and 16 controls) were evaluated through the Edinburgh Postnatal Depression Scale (EPDS), the State/Trait Anxiety Inventory Form Y (STAI-Y), and the Prenatal Attachment Inventory (PAI). A blood sample was collected from all participants, and OXT plasma levels, DNA methylation of clock genes, as well as of FOXp3 and HERV-W were measured. Linear regression analyses were performed to assess the effect of oxytocin on the methylation of selected genes. Continuous ordinal regression models was further applied to see if the score of rating scales was associated to gene methylation, adjusting for oxytocin-methylation interaction. Results: OXT plasma levels were positively associated with CRY1 methylation. Women with higher OXT plasma levels showed an association between higher degree of CRY2 methylation (thus, reduced expression) and lower EPDS (OR = 0.21; P = 0.043) and STAI-S scores (OR = 6.96; P = 0.019). Finally, with high OXT levels, hypermethylation of CRY1 was associated to higher scores on the PAI (OR = 2.74; P = 0.029) while higher methylation of HERV-W related to lower PAI scores (OR = 0.273; P = 0.019). Conclusion: Our results suggest a possible protective role played by oxytocin in the development of PD by promoting a favorable methylation profile characterized by reduced expression of CRY1 and CRY2. Moreover, oxytocin strengthens the association between maternal prenatal attachment with a favorable pattern of methylation of clock genes and HERV-W, which is essential for pregnancy outcomes.

Review of eating disorders and oxytocin receptor polymorphisms

BACKGROUND AND AIMS

Oxytocin, a nine amino acid peptide synthesised in the hypothalamus, has been widely recognised for its role in anxiolysis, bonding, sociality, and appetite. It binds to the oxytocin receptor (OXTR)-a G-protein coupled receptor-that is stimulated by the actions of oestrogen both peripherally and centrally. Studies have implicated OXTR genotypes in conferring either a risk or protective effect in autism, schizophrenia, and eating disorders (ED). There are numerous DNA variations of this receptor, with the most common DNA variation being in the form of the single nucleotide polymorphisms (SNPs). Two OXTR SNPs have been most studied in relation to ED: rs53576 and rs2254298. Each SNP has the same allelic variant that produces genotypes AA, AG, and GG. In this critical review we will evaluate the putative role of rs53576 and rs2254298 SNPs in ED. Additionally, this narrative review will consider the role of gene-environment interactions in the development of ED pathology.

FINDINGS

The OXTR SNPs rs53576 and rs2254298 show independent associations between the A allele and restrictive eating behaviours. Conversely, the G allele of the OXTR rs53576 SNP is associated with binging behaviours, findings that were also evident in neuroanatomy. One study found the A allele of both OXTR SNPs to confer risk for more severe ED symptomatology while the G allele conferred some protective effect. An interaction between poor maternal care and rs2254298 AG/AA genotype conferred increased risk for binge eating and purging in women.

CONCLUSIONS

Individual OXTR SNP are unlikely in themselves to explain complex eating disorders but may affect the expression of and/or effectiveness of the OXTR. A growing body of G x E work is indicating that rs53576G homozygosity becomes disadvantageous for later mental health under early adverse conditions but further research to extend these findings to eating pathology is needed. The GWAS approach would benefit this area of knowledge.

The association of oxytocin with major depressive disorder: role of confounding effects of antidepressants

Major depressive disorder is a genetic susceptible disease, and a psychiatric syndrome with a high rate of incidence and recurrence. Because of its complexity concerning etiology and pathogenesis, the cure rate of first-line antidepressants is low. In recent years, accumulative evidences revealed that oxytocin act as a physiological or pathological participant in a variety of complex neuropsychological activities, including major depressive disorder. Six electronic databases (Web of Science, PubMed, Scopus, Google Scholar, CNKI, and Wanfang) were employed for researching relevant publications. At last, 226 articles were extracted. The current review addresses the correlation of the oxytocin system and major depressive disorder. Besides, we summarize the mechanisms by which the oxytocin system exerts potential antidepressant effects, including regulating neuronal activity, influencing neuroplasticity and regeneration, altering neurotransmitter release, down regulating hypothalamic-pituitary-adrenal axis, anti-inflammatory, antioxidation, and genetic effects. Increasing evidence shows that oxytocin and its receptor gene may play a potential role in major depressive disorder. Future research should focus on the predictive ability of the oxytocin system as a biomarker, as well as its role in targeted prevention and early intervention of major depressive disorder.

Is There an Association Between Oxytocin Levels in Plasma and Pregnant Women's Mental Health?

BACKGROUND: Mood and anxiety disorders are prevalent in women during peripartum. AIMS: Purpose of the present article was to study the relationship between oxytocin (OT) plasma levels and affective symptoms in women during the third trimester of pregnancy. METHODS: Thirty-four pregnant women (13 with an affective disorder, 9 with preeclampsia, and 12 controls) were evaluated through the Edinburgh Postnatal Depression Scale (EPDS), the State/Trait Anxiety Inventory Form Y (STAI-Y), and the Prenatal Attachment Inventory (PAI). A blood sample was collected from all participants, and OT plasma levels have been compared between diagnostic groups. The total sample has been divided into two groups, according to OT median plasma levels, and compared using (a) χ² tests for qualitative variables and (b) a multivariate analysis of covariance for quantitative ones. RESULTS: No statistically significant difference was found among the diagnostic groups in terms of OT plasma levels (F = 0.49, p = .62). Women with lower OT plasma levels, independent from the presence of preeclampsia or an affective disorder, showed worse EPDS and STAI-S total scores than individuals with higher hormone levels (F = 5.93, p = .02 and F = 7.57, p = .01, respectively). CONCLUSIONS: OT may play a role in the etiology of anxious/depressive symptoms during perinatal period independent from a medical or psychiatric diagnosis. This result has a clear effect on the quality of the relationship of patients with mental health professionals, including nurses, and higher levels of this hormone, in the light of its anxiolytic and antidepressive effect, may make easier medical and nursing procedures.

LncRNA Gm14205 induces astrocytic NLRP3 inflammasome activation via inhibiting oxytocin receptor in postpartum depression

Postpartum depression (PPD) is a kind of mental disorder characterized by persistent low emotions in puerperium. The most significant physiological change in postpartum is lactation which is regulated by oxytocin receptor (OXTR). However, whether OXTR is related to pathological process of PPD and the potential mechanism still remain unclear. In the present study, we prepared hormone-simulated pregnancy (HSP)-induced PPD mouse model and found that the protein level of OXTR in hippocampus of PPD model mice was down-regulated and Nod-like receptor protein 3 (NLRP3) inflammasome was activated. We identified five long non-coding RNAs (lncRNAs) related to PPD by transcriptome sequencing, including three up-regulated and two down-regulated. The five lncRNAs were associated with the signaling pathway of OXTR according to the bioinformatics analysis. Furthermore, we focused on one of the five lncRNAs, Gm14205, and found that it targeted OXTR which inhibited astrocytic NLRP3 inflammasome activation in hippocampal primary astrocytes. These findings illustrate that OXTR has protective effects in PPD by inhibiting NLRP3 inflammasome activation and provides a new strategy for targeting lncRNA Gm14205 in the pathogenesis of PPD.

Epigenetics in Families: Covariance between Mother and Child Methylation Patterns

Theory and research both point at epigenetic processes affecting both parenting behavior and child functioning. However, little is known about the convergence of mother and child’s epigenetic patterns in families. Therefore, the current study investigated epigenetic covariance in mother–child dyads’ methylation levels regarding four stress-regulation related genes (5HTT, NR3C1, FKBP5, and BDNF). Covariance was tested in a general population sample, consisting of early adolescents (M_age = 11.63, SD_age = 2.3) and mothers (N = 160 dyads). Results showed that mother and offspring 5HTT and NR3C1 methylation patterns correlated. Furthermore, when averaged across genes, methylation levels strongly correlated. These findings partially supported that child and parent methylation levels covary. It might be important to consider this covariance to understand maladaptive parent–child relationships.

The role of epigenetics in perinatal depression: Are there any candidate biomarkers?

BACKGROUND

Approximately 12% of all women will be affected by Perinatal Depression (PD), a condition associated with an increased risk for low birth weight, preterm birth, preeclampsia, maternal suicide and infanticide. The identification of biomarkers for PD could be useful for early identification and for the development of new treatments. Purpose of the present manuscript is to review the potential epigenetic biomarkers which were associated with PD.

METHODS

We performed a bibliographic research on PubMed, in order to find studies that proposed epigenetic biomarkers for PD. A total of 9 studies met our inclusion criteria.

RESULTS

Most available data are concordant in showing that women affected by PD have epigenetic alterations versus Healthy Controls (HC), especially with regard to Hypothalamic Pituitary Adrenal (HPA) axis, oxytocin system, inflammatory response, neuronal differentiation and circadian rhythms. PD might be characterized by specific epigenetic changes; however, the available data are preliminary.

LIMITATIONS

Many articles report results obtained on a limited sample size, in different cell types or tissues. Furthermore, sometimes the studies selected a restricted number of genes. As a result, most available data have not been replicated.

CONCLUSIONS

Epigenetic changes of different biological systems could be involved in the etiology of PD. However, until now data are too scanty to draw definitive conclusions. Future studies with larger samples can confirm the results and hypothesis presented in this review.

A variation in the infant oxytocin receptor gene modulates infant hippocampal volumes in association with sex and prenatal maternal anxiety

Genetic variants in the oxytocin receptor (OTR) have been linked to distinct social phenotypes, psychiatric disorders and brain volume alterations in adults. However, to date, it is unknown how OTR genotype shapes prenatal brain development and whether it interacts with maternal prenatal environmental risk factors on infant brain volumes. In 105 Finnish mother-infant dyads (44 female, 11-54 days old), the association of offspring OTR genotype rs53576 and its interaction with prenatal maternal anxiety (revised Symptom Checklist 90, gestational weeks 14, 24, 34) on infant bilateral amygdalar, hippocampal and caudate volumes were probed. A sex-specific main effect of rs53576 on infant left hippocampal volumes was observed. In boys compared to girls, left hippocampal volumes were significantly larger in GG-homozygotes compared to A-allele carriers. Furthermore, genotype rs53576 and prenatal maternal anxiety significantly interacted on right hippocampal volumes irrespective of sex. Higher maternal anxiety was associated both with larger hippocampal volumes in A-allele carriers than GG-homozygotes, and, though statistically weak, also with smaller right caudate volumes in GG-homozygotes than A-allele carriers. Our study results suggest that OTR genotype enhances hippocampal neurogenesis in male GG-homozygotes. Further, prenatal maternal anxiety might induce brain alterations that render GG-homozygotes compared to A-allele carriers more vulnerable to depression.

Postpartum Depression: Current Status and Possible Identification Using Biomarkers

Postpartum depression (PPD) is a serious health issue that can affect about 15% of the female population within after giving birth. It often conveys significant negative consequences to the offsprings. The symptoms and risk factors are somewhat similar to those found in non-postpartum depression. The main difference resides in the fact that PPD is triggered by postpartum specific factors, including especially biological changes in the hormone levels. Patients are usually diagnosed using a questionnaire onsite or in a clinic. Treatment of PPD often involves psychotherapy and antidepressant medications. In recent years, there have been more researches on the identification of biological markers for PPD. In this review, we will focus on the current research status of PPD, with an emphasis on the recent progress made on the identification of PPD biomarkers.

Early life variations in temperature exposure affect the epigenetic regulation of the paraventricular nucleus in female rat pups

Early life maternal care received has a profound effect on later-life behaviour in adult offspring, and previous studies have suggested epigenetic mechanisms are involved. Changes in thyroid hormone receptor signalling may be related to differences in maternal care received and DNA methylation modifications. We investigated the effects of variations in temperature exposure (a proxy of maternal contact) and licking-like tactile stimulation on these processes in week-old female rat pups. We assessed thyroid hormone receptor signalling by measuring circulating triiodothyronine and transcript abundance of thyroid hormone receptors and the thyroid hormone-responsive genes DNA methyltransferase 3a and oxytocin in the paraventricular nucleus of the hypothalamus. DNA methylation of the oxytocin promoter was assessed in relation to changes in thyroid hormone receptor binding. Repeated room temperature exposure was associated with a decrease in thyroid hormone receptor signalling measures relative to nest temperature exposure, while acute room temperature exposure was associated with an increase. Repeated room temperature exposure also increased thyroid hormone receptor binding and DNA methylation at the oxytocin promoter. These findings suggest that repeated room temperature exposure may affect DNA methylation levels as a consequence of alterations in thyroid hormone receptor signalling.

Early Life Stress Induced DNA Methylation of Monoamine Oxidases Leads to Depressive-Like Behavior

Major depressive disorder (MDD) is coming to be the regarded as one of the leading causes for human disabilities. Due to its complicated pathological process, the etiology is still unclear and the treatment is still targeting at the monoamine neurotransmitters. Early life stress has been known as a major cause for MDD, but how early life stress affects adult monoaminergic activity is not clear either. Recently, DNA methylation is considered to be the key mechanism of epigenetics and might play a role in early life stress induced mental illness. DNA methylation is an enzymatic covalent modification of DNA, has been one of the main epigenetic mechanisms investigated. The metabolic enzyme for the monoamine neurotransmitters, monoamine oxidases A/B (MAO A/MAO B) are the prime candidates for the investigation into the role of DNA methylation in mental disorders. In this review, we will review recent advances about the structure and physiological function of monoamine oxidases (MAO), brief narrative other factors include stress induced changes, early life stress, perinatal depression (PD) relationship with other epigenetic changes, such as DNA methylation, microRNA (miRNA). This review will shed light on the epigenetic changes involved in MDD, which may provide potential targets for future therapeutics in depression pathogenesis.

Developments in the discovery and design of intranasal antidepressants

INTRODUCTION

Depression remains a major cause of morbidity worldwide; consequently, there is a need in neuropsychiatry for new antidepressants with a rapid onset of action. Intranasal administration of antidepressants is an attractive and promising approach to the treatment of mental disorders, as this route is noninvasive, offers a fast onset of action and improved drug bioavailability, allows a drug dose reduction, as well as gives the possibility to bypass the blood-brain barrier and reduce the number of systemic side effects.

AREAS COVERED

This review is a comprehensive discussion of the available intranasal drugs that have found application as antidepressants. The results of relevant clinical studies are presented. Additionally, the use of nanotechnology-based formulations for enhancing the intranasal delivery of antidepressants is briefly described.

EXPERT OPINION

Intranasal drug delivery has a huge potential for antidepressant administration, but its use in the treatment of central nervous system disorders is currently very limited. The nasal route of antidepressant delivery is noninvasive, improves drug bioavailability, as well as allows to overcome the problem with the blood-brain barrier, gastrointestinal absorption, and first-pass metabolism. In our opinion, fast-acting intranasal antidepressants will be widely used in the treatment of mental disorders in the future.

The role of glucocorticoid and mineralocorticoid receptor DNA methylation in antenatal depression and infant stress regulation

Understanding fetal programming pathways that underpin the relationship between maternal and offspring mental health necessitates an exploration of potential role of epigenetic variation in early development. Two genes involved in stress response regulation, the glucocorticoid and mineralocorticoid receptors (NR3C1 and NR3C2) have been a focus in understanding stressful exposures and mental health outcomes. Data were obtained from 236 pregnant women from the Mercy Pregnancy Emotional Wellbeing Study (MPEWS), a selected pregnancy cohort, recruited in early pregnancy. Depression was measured using the Structured Clinical Interview for DSM-IV (SCID-IV) and repeated measures of the Edinburgh Postnatal Depression Scale (EPDS). Antidepressant use, stressful events and anxiety symptoms were measured. NR3C1 and NR3C2 DNA methylation was measured in placental and infant buccal samples. Infant cortisol was measured in repeat saliva samples across a task. This study found maternal early pregnancy depressive disorder and symptoms were associated with lower DNA methylation at NR3C2 CpG_24 in placental tissue. There were no significant differences for depression or antidepressant use for DNA methylation of NR3C1. Antenatal depression was associated with lower infant cortisol reactivity at 12 months. DNA methylation in CpG_24 site in NR3C2 in placental samples suppressed the relationship between early maternal depressive symptoms and infant cortisol reactivity. These findings show a relationship between antenatal depression, NR3C2 DNA methylation and infant cortisol response providing support for a specific fetal programming pathway. Further research is required to examine the stability of this epigenetic mark across childhood and long-term mental health outcomes.

Regulation of social behaviors by p-Stat3 via oxytocin and its receptor in the nucleus accumbens of male Brandt's voles (Lasiopodomys brandtii)

Social behavior plays a significant role in the formation of social structure and population regulation in both animals and humans. Oxytocin (OXT) and its receptor (OXTR) are well known for regulating social behaviors, but their upstream regulating factors are rarely investigated. We hypothesized that the phosphorylation of the signal transducer and activator of transcription 3 (p-Stat3) may regulate social and aggressive behaviors via the OXT system in the nucleus accumbens (NAc). To test this hypothesis, OXT, p-Stat3 inhibitor, OXTR antagonist, and OXT plus p-Stat3 inhibitor were infused, respectively, into the NAc in the brain of male Brandt's voles (Lasiopodomys brandtii) - a social rodent species in grassland of Inner Mongolia, China. Our data showed that blockage of p-Stat3-Tyr⁷⁰⁵ signaling pathway in the NAc not only increased aggressive behavior but also impaired social recognition of male Brandt's voles via its effects on the expression of local OXT and OXTR. These results have illustrated a novel signaling pathway of p-Stat3-Tyr⁷⁰⁵ in regulating social behaviors via the OXT system.

Epigenetic signatures of attachment insecurity and childhood adversity provide evidence for role transition in the pathogenesis of perinatal depression

Early life adversity and insecure attachment style are known risk factors for perinatal depression. The biological pathways linking these experiences, however, have not yet been elucidated. We hypothesized that overlap in patterns of DNA methylation in association with each of these phenomena could identify genes and pathways of importance. Specifically, we wished to distinguish between allostatic-load and role-transition hypotheses of perinatal depression. We conducted a large-scale analysis of methylation patterns across 5 × 106 individual CG dinucleotides in 54 women participating in a longitudinal prospective study of perinatal depression, using clustering-based criteria for significance to control for multiple comparisons. We identified 1580 regions in which methylation density was associated with childhood adversity, 3 in which methylation density was associated with insecure attachment style, and 6 in which methylation density was associated with perinatal depression. Shorter telomeres were observed in association with childhood trauma but not with perinatal depression or attachment insecurity. A detailed analysis of methylation density in the oxytocin receptor gene revealed similar patterns of DNA methylation in association with perinatal depression and with insecure attachment style, while childhood trauma was associated with a distinct methylation pattern in this gene. Clinically, attachment style was strongly associated with depression only in pregnancy and the early postpartum, whereas the association of childhood adversity with depression was time-invariant. We concluded that the broad DNA methylation signature and reduced telomere length associated with childhood adversity could indicate increased allostatic load across multiple body systems, whereas perinatal depression and attachment insecurity may be narrower phenotypes with more limited DNA methylation signatures outside the CNS, and no apparent association with telomere length or, by extension, allostatic load. In contrast, the finding of matching DNA methylation patterns within the oxytocin receptor gene for perinatal depression and attachment insecurity is consistent with the theory that the perinatal period is a time of activation of existing attachment schemas for the purpose of structuring the mother-child relationship, and that such activation may occur in part through specific patterns of methylation of the oxytocin receptor gene.

Epigenetics, Gender, and Sex in the Diagnosis of Depression

Background :

A marked sexual dimorphism exists in psychiatric diagnoses. Culture derived gender bias in diagnostic criteria is one explanation. Adverse childhood events, including sexual and physical abuse, are more reliable and consistent predictors of later psychiatric diagnoses, including depression and post-traumatic stress disorder. Some interesting interactions between genes and experience have been uncovered, but the primary effect appears to be epigenetic with life experience altering gene expression and being transmitted to subsequent generations.

Objectives :

To determine if reconceptualizing depression as encompassing both internalizing and externalizing strategies would eliminate gender differences in the diagnosis of depression

Methods :

We reviewed 74 life stories of patients, collected during a study of the effect of physicians’ knowing patients’ life stories on the quality of the doctor-patient relationship. Looking at diagnoses, the prevalence of women to men was 2.9 to 1. We redefined depression as a response to being in a seemingly hopeless situation accompanied by despair, either externalizing ((more often diagnosed as substance use disorders, impulse control disorders, antisocial personality disorder, or bipolar disorder) or internalizing (the more standard diagnosis of depression). Then we reviewed these life stories from that perspective to determine how many would be diagnosed as depressed.

Results :

With this reconceptualization of depression, the sex ratio changed to 1.2 to 1.

Conclusions:

From this perspective, men and women are equally likely to respond to hopelessness, though men are more socialized to externalize and women to internalize. Considering depression in this way may help to better identify men at risk for suicide.

Sleep quality is associated with vasopressin methylation in pregnant and postpartum women with a history of psychosocial stress

BACKGROUND

The relationship between disturbed sleep and stress is well-documented. Sleep disorders and stress are highly prevalent during the perinatal period, and both are known to contribute to a number of adverse maternal and foetal outcomes. Arginine vasopressin (AVP) is a hormone and a neuropeptide that is involved in stress response, social bonding and circadian regulation of the sleep-wake cycle. Whether the AVP system is involved in regulation of stress response and sleep quality in the context of the perinatal mental health is currently unknown. The objective of the present study was to assess the relationship between levels of cumulative and ongoing psychosocial risk, levels of disordered sleep and AVP methylation in a community sample of pregnant and postpartum women.

METHODS

A sample of 316 participants completed a battery of questionnaires during the second trimester of pregnancy (PN2, 12-14 weeks gestation), third trimester (PN3, 32-34 weeks gestation), and at 7-9 weeks postpartum (PP). Disordered sleep was measured using the Sleep Symptom Checklist at PN2, PN3 and PP; cumulative psychosocial risk was assessed with the Antenatal Risk Questionnaire (ANRQ) at PN2; salivary DNA was collected at the follow-up (FU, 2.9 years postpartum); and % methylation were calculated for AVP and for two of the three AVP receptor genes (AVPR1a and AVPR1b). Women were separated into high (HighPR) and low (LowPR) psychosocial risk groups, based on their scores on the ANRQ.

RESULTS

Women in the HighPR group had significantly worse sleep disturbances during PN2 (p < .001) and PN3 (p < .001), but not at PP (p = .146) than women in the LowPR group. In HighPR participants only, methylation of AVP at intron 1 negatively correlated with sleep disturbances at PN2 (r_s=-.390, p = .001), PN3 (r_s=-.384, p = .002) and at PP (r_s= -.269, p = .032). There was no association between sleep disturbances and AVPR1a or AVPR1b methylation, or between sleep disturbances and any of the AVP methylation for the LowPR group. Lastly, cumulative psychosocial stress was a moderator for the relationship between AVP intron 1 methylation and disordered sleep at PN2 (p < .001, adjusted R² = .105), PN2 (p < .001, adjusted R² = .088) and PP (p = .003, adjusted R² = .064).

CONCLUSIONS

Our results suggest that cumulative psychosocial stress exacerbates sleep disorders in pregnant women, and that salivary DNA methylation patterns of the AVP gene may be seen as a marker of biological predisposition to stress and sleep reactivity during the perinatal period. Further research is needed to establish causal links between AVP methylation, sleep and stress.

The NeMo real-time fMRI neurofeedback study: protocol of a randomised controlled clinical intervention trial in the neural foundations of mother-infant bonding

INTRODUCTION

Most mothers feel an immediate, strong emotional bond with their newborn. On a neurobiological level, this is accompanied with the activation of the brain reward systems, including the striatum. However, approximately 10% of all mothers report difficulties to bond emotionally with their infant and display impaired reward responses to the interaction with their infant which might have long-term negative effects for the child's development. As previous studies suggest that activation of the striatal reward system can be regulated through functional MRI (fMRI)-based neurofeedback (NFB), we have designed and investigate fMRI-NFB training to treat maternal bonding difficulties.

METHODS AND ANALYSIS

In the planned trial, mothers will be presented pictures of their infant and real-time fMRI (rtfMRI), peripheral measures, neural, endocrine, psychophysiological and behavioural measures will be assessed. Mothers with bonding difficulties (n=68) will be randomised to one of two double-blind intervention groups at 4-6 months postpartum. They will participate in three repeated NFB training sessions with rtfMRI-NFB training to increase activation of (a) the ventral striatum or (b) the anterior cingulate. Interview data and real-time mother-infant interaction behaviour pre-intervention, post-intervention and at follow-up will serve as clinical outcome measures.

ETHICS AND DISSEMINATION

Study procedures are in line with the recommendations of the World Medical Association (revised Declaration of Helsinki) and were approved by the Ethics Committee of the Medical Faculty, s-450/2017, Heidelberg University. All participants will provide written informed consent after receiving a detailed oral and written explanation of all procedures and can withdraw their consent at any time without negative consequence. Results will be internationally published and disseminated, to further the discussion on non-pharmacological treatment options in complex mental disorders.

TRIAL REGISTRATION NUMBER

DRKS00014570; Pre-results.

The association between hormones and antipsychotic use: a focus on postpartum and menopausal women

During the postpartum and menopausal periods of women's lives, there is a well-established and significant drop of circulating estrogens. This may be the reason why both these periods are associated with an increased risk for onset or exacerbation of psychiatric disorders. Whether symptoms are mainly affective or mainly psychotic, these disorders are frequently treated with antipsychotic medications, which calls for an examination of the relationship between hormone replacement and antipsychotic agents at these time periods. The aim of this narrative review is to summarize what is known about the association of hormones and antipsychotics in the postnatal period and at menopause. In the review, we focus on estrogen and oxytocin hormones and include, for the most part, only papers published within the last 10 years. Both estradiol and oxytocin have at various times been implicated in the etiology of postpartum disorders, and estrogens, sometimes combined with progesterone, have been tested as potential treatments for these conditions. The role of estradiol as an adjunct to antipsychotics in the prevention of postpartum relapses is currently controversial. With respect to oxytocin, studies are lacking. Psychosis in menopausal and postmenopausal women has been successfully treated with estrogens and selective estrogen-receptor modulators, mainly raloxifene, in addition to antipsychotics. Some symptoms appear to respond better than others. No oxytocin study has specifically targeted postmenopausal women. Because of feedback mechanisms, there is a theoretical danger of therapy with exogenous hormones interfering with endogenous secretion and disturbing the balance among inter-related hormones. When used with antipsychotics, hormones may also affect the metabolism and, hence, the brain level of specific antipsychotics. This makes treatment with antipsychotics plus hormones complicated. Dose, timing and route of intervention may all prove critical to efficacy. While much remains unknown, this literature review indicates that, within standard dose ranges, the combination of hormones and antipsychotics for postnatal and menopausal women suffering severe mental distress can be beneficial, and is safe.

Methylation analysis for postpartum depression: a case control study

BACKGROUND

Postpartum depression (PPD) is a major depressive disorder that occurs after childbirth. Objective diagnostic and predictive methods for PPD are important for early detection and appropriate intervention. DNA methylation has been recognized as a potential biomarker for major depressive disorder. In this study, we used methylation analysis and peripheral blood to search for biomarkers that could to lead to the development a predictive method for PPD.

METHODS

Study participants included 36 pregnant women (18 cases and 18 controls determined after childbirth). Genome-wide DNA methylation profiles were obtained by analysis with an Infinium Human Methylation 450BeadChip. The association of DNA methylation status at each DNA methylation site with PPD was assessed using linear regression analysis. We also conducted functional enrichment analysis of PPD using The Database for Annotation, Visualization and Integrated Discovery 6.8 to explore enriched functional-related gene groups for PPD.

RESULTS

In the analysis with postpartum depressed state as an independent variable, the difference in methylation frequency between the postpartum non-depressed group and the postpartum depressed group was small, and sites with genome-wide significant differences were not confirmed. After analysis by The Database for Annotation, Visualization and Integrated Discovery 6.8, we revealed four gene ontology terms, including axon guidance, related to postpartum depression.

CONCLUSIONS

These findings may help with the development of an objective predictive method for PPD.

The maternal reward system in postpartum depression

The experience of motherhood is most often emotionally positive and rewarding, but for many new mothers suffering from postpartum depression (PPD), this is not the case. Preclinical and clinical research has sought to uncover brain changes underlying PPD in order to gain a better understanding of how this disorder develops. This review focuses on the mesolimbic dopamine system, particularly the ventral tegmental area-nucleus accumbens pathway which has been implicated in the regulation of critical functions disrupted in PPD including mood, motivation, and mothering. Specifically, we discuss normative changes in the mesolimbic system during motherhood in both rodents and humans and how these are impacted in PPD. We also consider modulation of mesolimbic dopamine by the hypothalamic neuropeptide oxytocin and how oxytocin-dopamine interactions regulate mood and mothering during the postpartum period. In addition to providing an overview of reward mechanisms in PPD, our goal is to highlight open questions which warrant further research.

The interaction between oxytocin receptor gene methylation and maternal behavior on children's early theory of mind abilities

Theory of mind, the ability to represent the mental states of others, is an important social cognitive process, which contributes to the development of social competence. Recent research suggests that interactions between gene and environmental factors, such as oxytocin receptor gene (OXTR) polymorphisms and maternal parenting behavior, may underlie individual differences in children's theory of mind. However, the potential influence of DNA methylation of OXTR remains unclear. The current study investigated the roles of OXTR methylation, maternal behavior, and their statistical interaction on toddlers' early emerging theory of mind abilities. Participants included a community sample of 189 dyads of mothers and their 2- to 3-year-old children, whose salivary DNA was analyzed. Results indicated that more maternal structuring behavior was associated with better performance, on a battery of three theory of mind tasks, while higher OXTR methylation within exon 3 was associated with poorer performance. A significant interaction also emerged, such that OXTR methylation was related to theory of mind among children whose mothers displayed less structuring, when controlling for children's age, sex, ethnicity, number of child-aged siblings, verbal ability, and maternal education. Maternal structuring behavior may buffer the potential negative impact of hypermethylation on OXTR gene expression and function.

Pharmacotherapy of Postpartum Depression: Current Approaches and Novel Drug Development

Postpartum depression is one of the most common complications of childbirth. Untreated postpartum depression can have substantial adverse effects on the well-being of the mother and child, negatively impacting child cognitive, behavioral, and emotional development with lasting consequences. There are a number of therapeutic interventions for postpartum depression including pharmacotherapy, psychotherapy, neuromodulation, and hormonal therapy among others, most of which have been adapted from the treatment of major depressive disorder outside of the peripartum period. Current evidence of antidepressant treatment for postpartum depression is limited by the small number of randomized clinical trials, underpowered samples, and the lack of long-term follow-up. The peripartum period is characterized by rapid and significant physiological change in plasma levels of endocrine hormones, peptides, and neuroactive steroids. Evidence supporting the role of neuroactive steroids and γ-aminobutyric acid (GABA) in the pathophysiology of postpartum depression led to the investigation of synthetic neuroactive steroids and their analogs as potential treatment for postpartum depression. Brexanolone, a soluble proprietary intravenous preparation of synthetic allopregnanolone, has been developed. A recent series of open-label and placebo-controlled randomized clinical trials of brexanolone in postpartum depression demonstrated a rapid reduction in depressive symptoms, and has led to the submission for regulatory approval to the US Food and Drug Administration (decision due in March 2019). SAGE-217, an allopregnanolone analog, with oral bioavailability, was recently tested in a randomized, double-blind, placebo-controlled phase III study in severe postpartum depression, with reportedly positive results. Finally, a 3β-methylated synthetic analog of allopregnanolone, ganaxolone, is being tested in both intravenous and oral forms, in randomized, double-blind, placebo-controlled phase II studies in severe postpartum depression.

Sex differences in depression: Insights from clinical and preclinical studies

Depression represents a global mental health concern, and disproportionally affects women as they are twice more likely to be diagnosed than men. In this review, we provide a summary of evidence to support the notion that differences in depression between men and women span multiple facets of the disease, including epidemiology, symptomology, treatment, and pathophysiology. Through a lens of biological sex, we overview depression-related transcriptional patterns, changes in neuroanatomy and neuroplasticity, and immune signatures. We acknowledge the unique physiological and behavioral demands of pregnancy and motherhood by devoting special attention to depression occurring in the peripartum period. Specifically, we discuss issues surrounding the presentation, time course, treatment, and neurobiology of peripartum depression. We write this review with the intention of highlighting the encouraging advancements in our understanding of sex differences in depression, while underscoring the gaps that remain. A more systematic consideration of biological sex as a variable in depression research will be critical in the discovery and development of pharmacotherapies that are efficacious for both men and women.