An association study between the Val66Met polymorphism of the BDNF gene and postpartum depression

Potential therapeutic effects of Chinese herbal medicine in postpartum depression: Mechanisms and future directions

ETHNOPHARMACOLOGICAL RELEVANCE

Postpartum depression (PPD) is a common psychiatric disorder in women after childbirth. Per data from epidemiologic studies, PPD affects about 5%-26.32% of postpartum mothers worldwide. Biological factors underlying this condition are multiple and complex and have received extensive inquiries for the roles they play in PPD. Chinese herbal medicine (CHM), which is widely used as a complementary and alternative therapy for neurological disorders, possesses multi-component, multi-target, multi-access, and low side effect therapeutic characteristics. CHM has already shown efficacy in the treatment of PPD, and a lot more research exploring the mechanisms of its potential therapeutic effects is being conducted.

AIM OF THE REVIEW

This review provides an in-depth and comprehensive overview of the underlying mechanisms of PPD, as well as samples the progress made in researching the potential role of CHM in treating the disorder.

MATERIALS AND METHODS

Literature was searched comprehensively in scholarly electronic databases, including PubMed, Web of Science, Scopus, CNKI and WanFang DATA, using the search terms "postpartum depression", "genetic", "hormone", "immune", "neuroinflammation", "inflammation", "neurotransmitter", "neurogenesis", "brain-gut axis", "traditional Chinese medicine", "Chinese herbal medicine", "herb", and an assorted combination of these terms.

RESULTS

PPD is closely associated with genetics, as well as with the hormones, immune inflammatory, and neurotransmitter systems, neurogenesis, and gut microbes, and these biological factors often interact and work together to cause PPD. For example, inflammatory factors could suppress the production of the neurotransmitter serotonin by inducing the regulation of tryptophan-kynurenine in the direction of neurotoxicity. Many CHM constituents improve anxiety- and depression-like behaviors by interfering with the above-mentioned mechanisms and have shown decent efficacy clinically against PPD. For example, Shen-Qi-Jie-Yu-Fang invigorates the neuroendocrine system by boosting the hormone levels of hypothalamic pituitary adrenal (HPA) and hypothalamic pituitary gonadal (HPG) axes, regulating the imbalance of Treg/T-helper cells (Th) 17 and Th1/Th2, and modulating neurotransmitter system to play antidepressant roles. The Shenguiren Mixture interferes with the extracellular signal-regulated kinase (ERK) pathway to enhance the number, morphology and apoptosis of neurons in the hippocampus of PPD rats. Other herbal extracts and active ingredients of CHM, such as Paeoniflorin, hypericin, timosaponin B-III and more, also manage depression by remedying the neuroendocrine system and reducing neuroinflammation.

CONCLUSIONS

The pathogenesis of PPD is complex and diverse, with the main pathogenesis not clear. Still, CHM constituents, like Shen-Qi-Jie-Yu-Fang, the Shenguiren Mixture, Paeoniflorin, hypericin and other Chinese Medicinal Formulae, active monomers and Crude extracts, treats PPD through multifaceted interventions. Therefore, developing more CHM components for the treatment of PPD is an essential step forward.

Risk Factors for Postpartum Depression Based on Genetic and Epigenetic Interactions

Postpartum depression (PPD) is a serious mood disorder that tends to occur after the delivery, which may bring lifelong consequences to women and their families in terms of family relationships, social relationships, and mental health. Currently, various risk factors including environmental factors and genetic factors that may induce postpartum depression have been extensively studied. In this review, we suggest that postpartum women's susceptibility to postpartum depression may be the result of the interaction between the genes associated with postpartum depression as well as the interaction between genetic and environmental factors. We reviewed the genes that have been studied in postpartum depression, including genes related to the synthesis, metabolism, and transport of monoamine neurotransmitters, key molecules of the HPA axis, and the kynurenine pathway. These studies have found more or less gene-gene and gene-environment interactions, so we will discuss these issues in more detail. However, so far, the conclusions of these risk factors, especially genetic factors, are not completely consistent in the occurrence and exacerbation of symptoms in postpartum depression, and it is not clear how these risk factors specifically participate in the pathological mechanism of the disease and play a role. We conclude that the role of genetic polymorphisms, including genetic and epigenetic processes, in the occurrence and development of postpartum depression, is complex and ambiguous. We also note that interactions between multiple candidate genes and the environment have been suggested as causes of depression, suggesting that more definitive research is needed to understand the heritability and susceptibility of PPD. Overall, our work supports the hypothesis that postpartum depression is more likely to be caused by a combination of multiple genetic and environmental factors than by a single genetic or environmental influence.

A pilot study of multilevel analysis of BDNF in paternal and maternal perinatal depression

Depression in the perinatal period is common in mothers worldwide. Emerging research indicates that fathers are also at risk of developing perinatal depression. However, knowledge regarding biological risk factors and pathophysiological mechanisms of perinatal depression is still scarce, particularly in fathers. It has been suggested that the neurotrophin BDNF may play a role in maternal perinatal depression; however, there is currently no data regarding paternal perinatal depression. For this pilot study, 81 expecting parents were recruited and assessed at several time points. We screened for depression using EPDS and MADRS, investigated several psychosocial variables, and took blood samples for BDNF val66met genotyping, epigenetic, and protein analysis. Between pregnancy and 12 months postpartum (pp), we found that 3.7 to 15.7% of fathers screened positive for depression, and 9.6 to 24% of mothers, with at least a twofold increased prevalence in both parents using MADRS compared with EPDS. We also identified several psychosocial factors associated with perinatal depression in both parents. The data revealed a trend that lower BDNF levels correlated with maternal depressive symptoms at 3 months pp. In the fathers, no significant correlations between BDNF and perinatal depression were found. Pregnant women demonstrated lower BDNF methylation and BDNF protein expression compared with men; however, these were found to increase postpartum. Lastly, we identified correlations between depressive symptoms and psychosocial/neurobiological factors. The data suggest that BDNF may play a role in maternal perinatal depression, but not paternal.

Sex steroids-induced neurogenesis in adult brain: a better look at mechanisms and mediators

Adult neurogenesis is the production of new nerve cells in the adult brain. Neurogenesis is a clear example of the neuroplasticity phenomenon which can be observed in most of mammalian species, including human beings. This phenomenon occurs, at least, in two regions of the brain: the subgranular zone of the dentate gyrus in hippocampus and the ventricular zone of lateral ventricles. Numerous studies have investigated the relationship between sex steroid hormones and neurogenesis of adult brain; of which, mostly concentrated on the role of estradiol. It has been shown that estrogen plays a significant role in this process through both classic and non-classic mechanisms, including a variety of different growth factors. Therefore, the objective of this review is to investigate the role of female sex steroids with an emphasis on estradiol and also its potential implications for regulating the neurogenesis in the adult brain.

Genome-wide gene expression changes in postpartum depression point towards an altered immune landscape

Maternal postpartum depression (PPD) is a significant public health concern due to the severe negative impact on maternal and child health and well-being. In this study, we aimed to identify genes associated with PPD. To do this, we investigated genome-wide gene expression profiles of pregnant women during their third trimester of pregnancy and tested the association of gene expression with perinatal depressive symptoms. A total of 137 women from a cohort from the University of North Carolina, USA were assessed. The main phenotypes analysed were Edinburgh Postnatal Depression Scale (EPDS) scores at 2 months postpartum and PPD (binary yes/no) based on an EPDS cutoff of 10. Illumina NextSeq500/550 transcriptomic sequencing from whole blood was analysed using the edgeR package. We identified 71 genes significantly associated with postpartum depression scores at 2 months, after correction for multiple testing at 5% FDR. These included several interesting candidates including TNFRSF17, previously reported to be significantly upregulated in women with PPD and MMP8, a matrix metalloproteinase gene, associated with depression in a genome-wide association study. Functional annotation of differentially expressed genes revealed an enrichment of immune response-related biological processes. Additional analysis of genes associated with changes in depressive symptoms from recruitment to 2 months postpartum identified 66 genes significant at an FDR of 5%. Of these genes, 33 genes were also associated with depressive symptoms at 2 months postpartum. Comparing the results with previous studies, we observed that 15.4% of genes associated with PPD in this study overlapped with 700 core maternal genes that showed significant gene expression changes across multiple brain regions (P = 7.9e-05) and 29-53% of the genes were also associated with estradiol changes in a pharmacological model of depression (P values range = 1.2e-4-2.1e-14). In conclusion, we identified novel genes and validated genes previously associated with oestrogen sensitivity in PPD. These results point towards the role of an altered immune transcriptomic landscape as a vulnerability factor for PPD.

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.

Association between serum BDNF levels and maternal perinatal depression: A review: Special Section on "Translational and Neuroscience Studies in Affective Disorders" Section Editor, Maria Nobile MD, PhD

INTRODUCTION

A large amount of studies demonstrated reduced serum Brain-Derived Neurotrophic Factor (BDNF) levels in stress-related and depressive disorders. However, it is still unclear if a similar deficit in BDNF concentrations might also characterize maternal perinatal depression.

METHODS

We performed a bibliographic search on PUBMED of all the studies investigating the association between maternal BDNF levels and perinatal depression. The inclusion criteria were met by thirteen studies.

RESULTS

Overall, the majority of the studies reported a significant reduction in serum BDNF levels among depressed mothers compared to healthy mothers either during pregnancy or in the postpartum period. Moreover, some studies also demonstrated that the BDNF reduction could be more evident in those depressed mothers with perinatal stressful life events and suicide risk.

LIMITATIONS

BDNF were collected at different time points across the studies. Potential confounding factors, including the clinical characteristics of the samples employed by the original studies, might have influenced the results.

CONCLUSIONS

So far, the evidences suggested the presence of decreased BDNF concentrations in perinatal depressive disorders. However, further studies are needed in order to confirm the role of BDNF in this disorder.

A systematic review investigating if genetic or epigenetic markers are associated with postnatal depression

BACKGROUND

Postnatal depression (PND) is common, affects the health of the mother, the development of the infant and places a large financial burden on services. Genetic and epigenetic biomarkers for PND could potentially improve the accuracy of current antenatal screening approaches. The aim of this systematic review is to report on the evidence for an association between genetic or epigenetic factors and postnatal depression.

METHOD

A systematic search of five databases (Medline, EMBASE, PILOT, PsychINFO and SCOPUS) was carried out using the following (MeSh) terms and keywords: postpartum, depression, postnatal depression, genetics, genetic polymorphisms and epigenetics. Inclusion criteria were applied and quality of studies was assessed using guidelines from the HuGE Review Handbook (Little and Higgins, 2006).

RESULTS

Following removal of duplicate articles, 543 remained; of these 37 met the inclusion criteria. Positive associations have been reported between PND and polymorphisms in the HMNC1, COMT, MAOT, PRKCB, ESR1, SLC6A4 genes in the presence of stressful life events, the BDNF gene when the postnatal period occurs during autumn and winter months and the OXT and OXTR genes in the presence of childhood adversity experienced by the mother. Epigenetic interactions with genotype, estrogen, and childhood adversity were identified that are predictive of PND.

LIMITATIONS

The number of studies investigating some of the markers was small and grey literature was not included.

CONCLUSION

This review highlights the importance of examining the interaction between epigenetic, genetic, hormonal and environmental factors in order to fully understand the risk factors for PND and to improve the accuracy of current antenatal and early postnatal screening procedures. Women susceptible to PND appear to have heightened epigenetic sensitivity to the physiological changes of childbirth or to environmental factors conferred by genotype.

Postpartum Depression: Pathophysiology, Treatment, and Emerging Therapeutics

Postpartum depression (PPD) is common, disabling, and treatable. The strongest risk factor is a history of mood or anxiety disorder, especially having active symptoms during pregnancy. As PPD is one of the most common complications of childbirth, it is vital to identify best treatments for optimal maternal, infant, and family outcomes. New understanding of PPD pathophysiology and emerging therapeutics offer the potential for new ways to add to current medications, somatic treatments, and evidence-based psychotherapy. The benefits and potential harms of treatment, including during breastfeeding, are presented.

Pathophysiological mechanisms implicated in postpartum depression

This review aims to summarize the diverse proposed pathophysiological mechanisms contributing to postpartum depression, highlighting both clinical and basic science research findings. The risk factors for developing postpartum depression are discussed, which may provide insight into potential neurobiological underpinnings. The evidence supporting a role for neuroendocrine changes, neuroinflammation, neurotransmitter alterations, circuit dysfunction, and the involvement of genetics and epigenetics in the pathophysiology of postpartum depression are discussed. This review integrates clinical and preclinical findings and highlights the diversity in the patient population, in which numerous pathophysiological changes may contribute to this disorder. Finally, we attempt to integrate these findings to understand how diverse neurobiological changes may contribute to a common pathological phenotype. This review is meant to serve as a comprehensive resource reviewing the proposed pathophysiological mechanisms underlying postpartum depression.

Gene expression profile in peripheral blood mononuclear cells of postpartum depression patients

Postpartum depression (PPD) is a common mental health problem that causes maternal suffering and various negative consequences for offspring. The pathogenesis of PPD and the causes of consequences for offspring remain largely unknown. Here, we applied RNA sequencing to sequence the whole transcriptomes of peripheral blood mononuclear cells (PBMCs) from PPD patients (Edinburgh Postnatal Depression Scale [EPDS] score ≥13) and control subjects (EPDS = 0). We found that PPD was positively correlated with multiple genes involved in energy metabolism, neurodegenerative diseases and immune response, while negatively correlated with multiple genes in mismatch repair and cancer-related pathways. Remarkably, genes associated with appetite regulation and nutrient response were differentially expressed between PPD and control subjects. Then, we employed a postnatal growth retardation model by repeated immobilization stress (IS) stimulation to maternal mice. The expression of appetite regulation and nutrient response-related genes in the PBMCs of IS mice and in the hypothalamus of their offspring were also affected. In conclusion, this study provides a comprehensive characterization of the PBMCs transcriptome in PPD and suggests that maternal stress may affect appetite regulation and nutrient response in the hypothalamus of offspring mice.

Parallels between Postpartum Disorders in Humans and Preweaning Piglet Mortality in Sows

Simple Summary

Humans and sows are both highly social species that exhibit a wide variety of maternal behaviors and responsivity to pregnancy and parturition. Piglet crushing is a production and welfare concern for the swine industry. Similar to rates of postpartum depression in humans, the performance of piglet crushing is more likely in first-time mothers. Furthermore, hormonal profiles and social factors that influence the development of this disease in humans mirror those observed in sows surrounding parturition. This article reviews the biological, social, and management factors that may be contributing to this problem of piglet crushing through the lens of how postpartum depression develops in humans. Utilizing knowledge from human psychology and animal welfare science may provide producers with management tools to mitigate piglet crushing and provide new insight into the factors that contribute to human postpartum disorders.

Abstract

Pregnancy and parturition in all mammals is accompanied with physical, psychological, social, and hormonal shifts that impact the mother physically and psychologically. Pre-weaning piglet mortality continues to be a major welfare and economic issue in U.S. swine production, running at 12–15% with crushing by the sow the major cause. Much research has focused on farrowing environment design, yet the fact that little progress has been made emphasizes that psychosocial factors may impact rates of postpartum disorders (PPD). There is a mismatch between evolved adaptations and contemporary psychosocial and management practices. Many factors associated with the development of PPD in humans are mirrored in sows that perform piglet crushing. These factors include poor mental welfare (anxiety, difficulty coping with stress), a lack of experience, a lack of social support, and individual differences in their sensitivity to hormone concentrations. Understanding what strategies are effective in preventing PPD in humans may have welfare and production benefits for sows—and sows may be a possible model for better understanding PPD in humans.

Reproductive Affective Disorders: a Review of the Genetic Evidence for Premenstrual Dysphoric Disorder and Postpartum Depression

PURPOSE OF REVIEW

The purpose of this study is to review and summarize the literature exploring the genetic basis for premenstrual dysphoric disorder (PMDD) and postpartum depression (PPD).

RECENT FINDINGS

There is more evidence for a genetic basis for PPD than for PMDD, but only when PPD is defined as beginning in the immediate postpartum time period. Familial, genome-wide linkage and association studies, and candidate gene studies, most in the past 10 years, have examined the genetic etiology of reproductive affective disorders, including PMDD and PPD. The most commonly studied genes include SERT, COMT, MAOA, BDNF, and ESR1 and 2. This qualitative review of the recent literature finds limited evidence so far for the genetic basis for PMDD, with both familial and candidate gene studies having negative or conflicting results. Evidence is stronger for the genetic basis for PPD, with positive associations found in family studies and in several genes associated with major depression as well as genes involved in estrogen signaling but only when PPD onset is shortly after delivery. Epigenetic biomarkers on genes responsive to estrogen have also been found to predict PPD. Our findings underscore the need for additional studies with larger samples, as well as the crucial importance of timing in the definition of PPD for genetic studies.

Serum BDNF concentration after delivery is associated with development of postpartum depression: A 3-month follow up study

BACKGROUND

Our aim was to determine whether there is a relationship between serum brain-derived neurotrophic factor (BDNF) and postpartum depression (PPD) in a cohort Chinese population.

METHODS

From May 1, 2014, to September 30, 2014, all eligible women not on medication for depression giving birth at the Fourth Affiliated Hospital of Harbin Medical University were consecutively recruited and followed up for 3 months. At 3 months postpartum, women were screened for depression using the Edinburgh Postnatal Depression Scale (EPDS). The primary outcome measure was an EPDS score of > or =12. Enzyme-linked immunosorbent assay (ELISA) was used to measure serum levels of BDNF at admission. Multivariate analyses were performed using logistic regression models.

RESULTS

During the study period, 340 women were enrolled and completed follow-up. In those women, 37 women (10.9%) were considered as meeting criteria for PPD. Serum BDNF levels in women without PPD were significantly higher than those in women with PPD (P<0.0001). Based on the ROC curve, the optimal cutoff value of serum BDNF levels as an indicator for screening of PPD was estimated to be 12.0ng/ml, which yielded a sensitivity of 82.8% and a specificity of 72.6%, with the area under the curve at 0.809 (95%CI, 0.731-0.887). In multivariate analysis, there was an increased risk of PPD associated with BDNF levels ≤12.0ng/ml (OR 7.243, 95% CI: 3.883-12.746; P<0.0001) after adjusting for possible confounders.

CONCLUSION

The present study demonstrates a strong relationship between reduced serum BDNF levels at admission and the development of PPD within the 3 months.

Perinatal Major Depression Biomarkers: A systematic review

Postpartum depression, now termed perinatal depression by the DSM-5, is a clinically relevant disorder reaching 15% of incidence. Although it is quite frequent and associated with high social dysfunction, only recently its underpinning biological pathways have been explored, while multiple and concomitant risk factors have been identified (e.g. psychosocial stress). Peripartum depression usually has its onset during the third trimester of pregnancy or in the postpartum, being one of the most common medical complications in new mothers. Purpose of the present review is to summarize the state of art of biological biomarkers involved in the pathogenesis of perinatal depression, in view of the fact that suboptimal prenatal milieu can induce permanent damage in subsequent offspring life and have a negative impact on mother-child relationship. Furthermore, parents' biological changes due to medical/psychiatric disorders or stress exposure could influence offspring life: a concept known as 'intergenerational transmission', acting by variations into gametes and the gestational uterine environment. Given the evidence that perinatal mental disorders involve risks for the mother and offspring, the search for reliable biomarkers in high-risk mothers actually represents a medical priority to prevent perinatal depression.

Brain Reward Pathway Dysfunction in Maternal Depression and Addiction: A Present and Future Transgenerational Risk

Two research areas that could benefit from a greater focus on the role of the reward pathway are maternal depression and maternal addiction. Both depression and addiction in mothers are mediated by deficiencies in the reward pathway and represent substantial risks to the health of offspring and future generations. This targeted review discusses maternal reward deficits in depressed and addicted mothers, neural, genetic, and epigenetic mechanisms, and the transgenerational transmission of these deficits from mother to offspring. Postpartum depression and drug use disorders may entail alterations in the reward pathway, particularly in striatal and prefrontal areas, which may affect maternal attachment to offspring and heighten the risk of transgenerational effects on the oxytocin and dopamine systems. Alterations may involve neural circuitry changes, genetic factors that impact monoaminergic neurotransmission, as well as growth factors such as BDNF and stress-associated signaling in the brain. Improved maternal reward-based preventative measures and treatments may be specifically effective for mothers and their offspring suffering from depression and/or addiction.

Bidirectional psychoneuroimmune interactions in the early postpartum period influence risk of postpartum depression

More than 500,000 U.S. women develop postpartum depression (PPD) annually. Although psychosocial risks are known, the underlying biology remains unclear. Dysregulation of the immune inflammatory response and the hypothalamic-pituitary-adrenal (HPA) axis are associated with depression in other populations. While significant research on the contribution of these systems to the development of PPD has been conducted, results have been inconclusive. This is partly because few studies have focused on whether disruption in the bidirectional and dynamic interaction between the inflammatory response and the HPA axis together influence PPD. In this study, we tested the hypothesis that disruption in the inflammatory-HPA axis bidirectional relationship would increase the risk of PPD. Plasma pro- and anti-inflammatory cytokines were measured in women during the 3rd trimester of pregnancy and on Days 7 and 14, and Months 1, 2, 3, and 6 after childbirth. Saliva was collected 5 times the day preceding blood draws for determination of cortisol area under the curve (AUC) and depressive symptoms were measured using the Edinburgh Postpartum Depression Survey (EPDS). Of the 152 women who completed the EPDS, 18% were depressed according to EDPS criteria within the 6months postpartum. Cortisol AUC was higher in symptomatic women on Day 14 (p=.017). To consider the combined effects of cytokines and cortisol on predicting symptoms of PPD, a multiple logistic regression model was developed that included predictors identified in bivariate analyses to have an effect on depressive symptoms. Results indicated that family history of depression, day 14 cortisol AUC, and the day 14 IL8/IL10 ratio were significant predictors of PPD symptoms. One unit increase each in the IL8/IL10 ratio and cortisol AUC resulted in 1.50 (p=0.06) and 2.16 (p=0.02) fold increases respectively in the development of PPD. Overall, this model correctly classified 84.2% of individuals in their respective groups. Findings suggest that variability in the complex interaction between the inflammatory response and the HPA axis influence the risk of PPD.

Depressive symptoms, pain, and sexual dysfunction over the first year following vaginal or cesarean delivery: A prospective longitudinal study

BACKGROUND

Childbirth has a significant impact on maternal health, and the high rate of cesarean delivery is a global health concern. Few studies have used validated measures to explore depression, pain, and sexual dysfunction following vaginal or cesarean delivery over a prolonged time period.

OBJECTIVE

We examined the associations between vaginal and cesarean delivery and depressive symptoms, pain, and sexual function during the 1-year postpartum period.

DESIGN

A prospective, five-time-point longitudinal study.

SETTING

Maternity unit at a medical center.

PARTICIPANTS

A total of 351 of 736 women completed a questionnaire that described demographic characteristics, depressive symptoms, and pain levels at 3-5 days postpartum, and updated personal data, depressive symptoms, pain levels, and sexual function at 4-6 weeks and at 3, 6, and 12 months after delivery.

METHODS

Differences between the vaginal and cesarean groups in depressive symptoms, pain, and sexual function and trends of changes in these factors over the first postpartum year were examined.

RESULTS

Compared with the vaginal birth group, the cesarean birth group had a significantly higher prevalence of depressive symptoms at 3 months (p=0.03); higher scores for non-localized pain at 3-5 days (p<0.001), 4-6 weeks (p=0.03), and 3 months (p=0.046); higher scores for abdominal pain at 3-5 days (p<0.001), 4-6 weeks (p<0.001), and 6 months (p=0.01); lower perineal pain scores at 3-5 days (p <0.001); and higher sexual desire scores (p=0.04) but lower sexual satisfaction scores (p=0.02) at 4-6 weeks. Differences between the vaginal and cesarean groups were significant (p=0.01, p=0.049, respectively) in terms of the decrease in non-localized pain from 3-5 days to 4-6 weeks postpartum and the increase in sexual desire from 4-6 weeks to 3 months postpartum.

CONCLUSIONS

Cesarean delivery was associated with an increased prevalence of depressive symptoms at 3 months and higher pain levels that persisted at 6 months postpartum in Taiwan. We found no difference in sexual function between vaginal and cesarean delivery after 6 weeks postpartum, and no differences in the trends related to depressive symptoms or in sexual functioning (except for desire) within 1 year postpartum.

Postpartum depression: A systematic review of the genetics involved

Postpartum depression is one of the most prevalent psychopathologies. Its prevalence is estimated to be between 10% and 15%. Despite its multifactorial etiology, it is known that genetics play an important role in the genesis of this disorder. This paper reviews epidemiological evidence supporting the role of genetics in postpartum depression (PPD). The main objectives of this review are to determine which genes and polymorphisms are associated with PPD and discuss how this association may occur. In addition, this paper explores whether these genes are somehow related to or even the same as those linked to Major Depression (MD). To identify gaps in the current knowledge that require investigation, a systematic review was conducted in the electronic databases PubMed, LILACS and SciELO using the index terms “postpartum depression” and “genetics”. Literature searches for articles in peer-reviewed journals were made until April 2014. PPD was indexed 56 times with genetics. The inclusion criteria were articles in Portuguese, Spanish or English that were available by institutional means or sent by authors upon request; this search resulted in 20 papers. Genes and polymorphisms traditionally related to MD, which are those involved in the serotonin, catecholamine, brain-derived neurotrophic factor and tryptophan metabolism, have been the most studied, and some have been related to PPD. The results are conflicting and some depend on epigenetics, which makes the data incipient. Further studies are required to determine the genes that are involved in PPD and establish the nature of the relationship between these genes and PPD.

The Influence of genetic factors on peripartum depression: A systematic review

BACKGROUND

This systematic review aimed to explore the potential influence of genetic factors on the symptoms of peripartum depression and to critically analyze the methodologies employed by the examined studies.

METHODS

A systematic review of the literature indexed prior to July 2014 identified 200 articles. After applying the inclusion and exclusion criteria, 39 papers were included.

RESULTS

The papers predominantly featured a molecular genetic approach (n=35), and the majority examined polymorphisms (n=27). Most studies used samples of Caucasians living in high income countries. The results suggest that the influence of genetic factors become more consistent when methodological variations among the studies are considered. Environmental stressors are also important variables that influence the relationship between genetic factors and peripartum depressive states. In addition, differences in the influence of genetic factors were observed depending upon the precise time point during pregnancy or the postpartum period that was examined in the studies. The late stages of pregnancy and the early postpartum period were times of greater genetic vulnerability.

LIMITATIONS

This study was limited by the small number of papers reviewed and by the lack of information regarding whether the effects of genetics on peripartum depression are specific to certain ethnicities and/or stressors.

CONCLUSIONS

Genetic studies of perinatal depression reinforce a pathophysiological role of the hormonal changes inherent in the childbirth period. However, the distinction between depressive episodes that begin during pregnancy from those that begin during the postpartum period can still be useful to improve our understanding of the physiopathology of depressive disorders.

The role of reproductive hormones in postpartum depression

Despite decades of research aimed at identifying the causes of postpartum depression (PPD), PPD remains common, and the causes are poorly understood. Many have attributed the onset of PPD to the rapid perinatal change in reproductive hormones. Although a number of human and nonhuman animal studies support the role of reproductive hormones in PPD, several studies have failed to detect an association between hormone concentrations and PPD. The purpose of this review is to examine the hypothesis that fluctuations in reproductive hormone levels during pregnancy and the postpartum period trigger PPD in susceptible women. We discuss and integrate the literature on animal models of PPD and human studies of reproductive hormones and PPD. We also discuss alternative biological models of PPD to demonstrate the potential for multiple PPD phenotypes and to describe the complex interplay of changing reproductive hormones and alterations in thyroid function, immune function, hypothalamic-pituitary-adrenal (HPA) axis function, lactogenic hormones, and genetic expression that may contribute to affective dysfunction. There are 3 primary lines of inquiry that have addressed the role of reproductive hormones in PPD: nonhuman animal studies, correlational studies of postpartum hormone levels and mood symptoms, and hormone manipulation studies. Reproductive hormones influence virtually every biological system implicated in PPD, and a subgroup of women seem to be particularly sensitive to the effects of perinatal changes in hormone levels. We propose that these women constitute a "hormone-sensitive" PPD phenotype, which should be studied independent of other PPD phenotypes to identify underlying pathophysiology and develop novel treatment targets.

Biological and psychosocial predictors of postpartum depression: systematic review and call for integration

Postpartum depression (PPD) adversely affects the health and well being of many new mothers, their infants, and their families. A comprehensive understanding of biopsychosocial precursors to PPD is needed to solidify the current evidence base for best practices in translation. We conducted a systematic review of research published from 2000 through 2013 on biological and psychosocial factors associated with PPD and postpartum depressive symptoms. Two hundred fourteen publications based on 199 investigations of 151,651 women in the first postpartum year met inclusion criteria. The biological and psychosocial literatures are largely distinct, and few studies provide integrative analyses. The strongest PPD risk predictors among biological processes are hypothalamic-pituitary-adrenal dysregulation, inflammatory processes, and genetic vulnerabilities. Among psychosocial factors, the strongest predictors are severe life events, some forms of chronic strain, relationship quality, and support from partner and mother. Fully integrated biopsychosocial investigations with large samples are needed to advance our knowledge of PPD etiology.

Using animal models to study post-partum psychiatric disorders

The post-partum period represents a time during which all maternal organisms undergo substantial plasticity in a wide variety of systems in order to ensure the well-being of the offspring. Although this time is generally associated with increased calmness and decreased stress responses, for a substantial subset of mothers, this period represents a time of particular risk for the onset of psychiatric disorders. Thus, post-partum anxiety, depression and, to a lesser extent, psychosis may develop, and not only affect the well-being of the mother but also place at risk the long-term health of the infant. Although the risk factors for these disorders, as well as normal peripartum-associated adaptations, are well known, the underlying aetiology of post-partum psychiatric disorders remains poorly understood. However, there have been a number of attempts to model these disorders in basic research, which aim to reveal their underlying mechanisms. In the following review, we first discuss known peripartum adaptations and then describe post-partum mood and anxiety disorders, including their risk factors, prevalence and symptoms. Thereafter, we discuss the animal models that have been designed in order to study them and what they have revealed about their aetiology to date. Overall, these studies show that it is feasible to study such complex disorders in animal models, but that more needs to be done in order to increase our knowledge of these severe and debilitating mood and anxiety disorders.

Association study of the estrogen receptor gene ESR1 with postpartum depression--a pilot study

Perinatal mood disorders, such as postpartum depression (PPD), are costly for society, with potentially serious consequences for mother and child. While multiple genes appear to play a role in PPD susceptibility, the contributions of specific genetic variations remain unclear. Previously implicated as a candidate gene, the estrogen receptor alpha gene (ESR1) is a key player in mediating hormonal differences during pregnancy and the postpartum period. This study addresses genetic factors in perinatal mood disorders, testing nine polymorphisms in ESR1. Two hundred fifty-seven postpartum women were screened for mood disorders, including 52 women with PPD and 32 without any symptoms of mood disorders. We detected a significant association for the upstream TA microsatellite repeat with Edinburgh Postnatal Depression Scale scores (p = 0.007). The same variant was also associated with the occurrence of PPD. Separately, 11 candidate functional polymorphisms in 7 additional genes were genotyped to investigate gene-gene interaction with the ESR1 TA repeat, identifying a potential interaction with the serotonin transporter. Our results support a role for ESR1 in the etiology of PPD, possibly through the modulation of serotonin signaling. Our findings for ESR1 could have broad implications for other disorders and therapies that involve estrogens.

Bridging animal and human models of exercise-induced brain plasticity

Significant progress has been made in understanding the neurobiological mechanisms through which exercise protects and restores the brain. In this feature review, we integrate animal and human research, examining physical activity effects across multiple levels of description (neurons up to inter-regional pathways). We evaluate the influence of exercise on hippocampal structure and function, addressing common themes such as spatial memory and pattern separation, brain structure and plasticity, neurotrophic factors, and vasculature. Areas of research focused more within species, such as hippocampal neurogenesis in rodents, also provide crucial insight into the protective role of physical activity. Overall, converging evidence suggests exercise benefits brain function and cognition across the mammalian lifespan, which may translate into reduced risk for Alzheimer's disease (AD) in humans.

Biological aspects of postpartum depression

In comparison with the vast epidemiological literature on postpartum depression (PPD), relatively few studies have examined the biological aspects of the disorder. However, research into the biological mechanisms of PPD is a challenging task, as normal pregnancy and the postpartum period cause adaptive endocrine changes, which would otherwise be considered pathological in nonpregnant women. This review focuses on the adaptive changes of childbearing and nursing, which ultimately may put women at increased risk of PPD. In light of the normal physiology, the authors also attempt to describe the current evidence of the biological changes associated with the development of depression in the postpartum period, including ovarian steroids, the hypothalamic-pituitary-adrenal axis, the serotonergic neurotransmitter system, the thyroid system and inflammatory markers. In addition, current knowledge on candidate genes associated with PPD is reviewed.

Brain-derived neurotrophic factor serum levels and genotype: association with depression during interferon-α treatment

Depression has been associated with inflammation, and inflammation may both influence and interact with growth factors such as brain-derived neurotrophic factor (BDNF). Both the functional Val66Met BDNF polymorphism (rs6265) and BDNF levels have been associated with depression. It is thus plausible that decreased BDNF could mediate and/or moderate cytokine-induced depression. We therefore prospectively employed the Beck Depression Inventory-II (BDI-II), the Hospital Anxiety and Depression Scale (HADS), and the Montgomery-Asberg Depression Rating Scale (MADRS) in 124 initially euthymic patients during treatment with interferon-alpha (IFN-α), assessing serum BDNF and rs6265. Using mixed-effect repeated measures, lower pretreatment BDNF was associated with higher depression symptoms during IFN-α treatment (F144,17.2=6.8; P<0.0001). However, although the Met allele was associated with lower BDNF levels (F1,83.0=5.0; P=0.03), it was only associated with increased MADRS scores (F4,8.9=20.3; P<0.001), and not the BDI-II or HADS. An exploratory comparison of individual BDI-II items indicated that the Met allele was associated with suicidal ideation, sadness, and worthlessness, but not neurovegetative symptoms. Conversely, the serotonin transporter promoter polymorphism (5-HTTLPR) short allele was associated with neurovegetative symptoms such as insomnia, poor appetite and fatigue, but not sadness, worthlessness, or suicidal ideation. IFN-α therapy further lowered BDNF serum levels (F4,37.7=5.0; P=0.003), but this decrease occurred regardless of depression development. The findings thus do not support the hypothesis that decreasing BDNF is the primary pathway by which IFN-α worsens depression. Nonetheless, the results support the hypothesis that BDNF levels influence resiliency against developing inflammatory cytokine-associated depression, and specifically to a subset of symptoms distinct from those influenced by 5-HTTLPR.

Reprint of: Effects of BDNF polymorphisms on brain function and behavior in health and disease

Brain-derived neurotrophic factor (BDNF), the most abundant neurotrophin in the brain, serves an important role during brain development and in synaptic plasticity. Given its pleiotropic effects in the central nervous system, BDNF has been implicated in cognitive function and personality development as well as the pathogenesis of various psychiatric disorders. Thus, BDNF is considered an attractive candidate gene for the study of healthy and diseased brain function and behaviors. Over the past decade, many studies have tested BDNF genetic association, particularly its functional Val66Met polymorphism, with psychiatric diseases, personality disorders, and cognitive function. Although many reports indicated a possible role for BDNF genetic effects in mental problems or brain function, other reports were unable to replicate the findings. The conflicting results in BDNF genetic studies may result from confounding factors such as age, gender, other environmental factors, sample size, ethnicity and phenotype assessment. Future studies with more homogenous populations, well-controlled confounding factors, and well-defined phenotypes are needed to clarify the BDNF genetic effects on mental diseases and human behaviors.

Postpartum depressive symptoms and the BDNF Val66Met functional polymorphism: effect of season of delivery

Postpartum depression (PPD) is an often underdiagnosed and undertreated mood disorder, with negative impact on the mother's and infant's health. Seasonal variation has been discussed as a risk factor for PPD. Candidate genes, such as those encoding for the brain-derived neurotrophic factor (BDNF), serotonin transporter (5-HTT), and Period2 (PER2), have been associated with depression and seasonal disorders. The present study is aimed to examine whether functional polymorphic variants, BDNF Val66Met, 5-HTTLPR, or PER2 SNP 10870, are associated with PPD symptoms and whether these genetic polymorphisms interact with season in predicting PPD symptoms. This case-control study comprised of 275 women from a population-based cohort of delivering women in Sweden, who completed a questionnaire containing the Edinburgh postnatal depression scale (EPDS) at 6 weeks and 6 months postpartum. Stressful life events (SLEs) and maternity stressors were also assessed. The results did not reveal any statistically significant overall association between the studied genetic polymorphisms and PPD symptoms. However, a significant association between BDNF Met66 carrier status and development of PPD symptoms at 6 weeks postpartum, even when controlling for prepartum and postpartum environmental risk factors, was evident among mothers delivering during autumn/winter. No gene-gene interactions were found but a cumulative effect was detected with carriers of a greater number of 5-HTTLPR S and BDNFVal66Met Met alleles reporting higher EPDS scores, if delivered during autumn/winter. Our findings propose a role of the BDNF gene in the development of PPD symptoms, potentially mediated by season of delivery.

Interaction between BDNF Val66Met and childhood stressful life events is associated to affective memory bias in men but not women

Recent meta-analyses point towards a pathogenic role of the Val66Met variant of the brain-derived neurotrophic factor (BDNF) in major depressive disorder, specifically in males. We investigated whether BDNF Val66Met shows a male-specific interaction with childhood stressful life events on affective memory bias, a cognitive susceptibility factor for depression. Healthy volunteers (n=430; 272 females and 158 males) were genotyped for BDNF Val66Met (rs6265) and completed the self-referent encoding task and a childhood stressful life events scale. BDNF Met carriers reporting childhood events tended to recall a lower proportion of positive words compared to Val/Val homozygotes reporting childhood events. Sex-specific analyses revealed that the BDNF genotype×childhood events interaction was significant in male participants and not in female participants. The results suggest that in males, BDNF Val66Met interacts with childhood life events, increasing the cognitive susceptibility markers of depression. In females, this effect may be independent of BDNF Val66Met.

Effects of BDNF polymorphisms on brain function and behavior in health and disease

Brain-derived neurotrophic factor (BDNF), the most abundant neurotrophin in the brain, serves an important role during brain development and in synaptic plasticity. Given its pleiotropic effects in the central nervous system, BDNF has been implicated in cognitive function and personality development as well as the pathogenesis of various psychiatric disorders. Thus, BDNF is considered an attractive candidate gene for the study of healthy and diseased brain function and behaviors. Over the past decade, many studies have tested BDNF genetic association, particularly its functional Val66Met polymorphism, with psychiatric diseases, personality disorders, and cognitive function. Although many reports indicated a possible role for BDNF genetic effects in mental problems or brain function, other reports were unable to replicate the findings. The conflicting results in BDNF genetic studies may result from confounding factors such as age, gender, other environmental factors, sample size, ethnicity and phenotype assessment. Future studies with more homogenous populations, well-controlled confounding factors, and well-defined phenotypes are needed to clarify the BDNF genetic effects on mental diseases and human behaviors.

The role of BDNF genetic polymorphisms in bipolar disorder with psychiatric comorbidities

BACKGROUND

Bipolar disorder (BD) is a complex disorder where genetic factors play a major role in its etiology. Probably, no other axis I diagnosis has a co-morbidity prevalence as high as BD. Since BDNF is involved in different ways in various psychiatric disorders we hypothesized that its genetic polymorphisms could be associated with the co-morbidity phenomenon in BD.

METHODS

We studied 320 subjects (160 BD patients and 160 healthy controls). Genotyping was performed using made-to-order TaqMan genotyping assays (rs4923463, rs6265, rs2049045, and rs7103411). Statistical analyses were performed using UNPHASED version 3.0.12 and Haploview 4.1.

RESULTS

No genotypic, allelic or haplotype differences were found between bipolar patients and healthy controls. Concerning exclusively the rs4923463 (G/G) there was a significant association with alcoholism (p=0.009), smoking (p=0.006) and violent suicide attempt (p=0.03). We further found that the G-G haplotype (rs4923463-rs2049045) (adjusted p=0.029) and the G-T haplotype (rs4923463-rs7103411) (adjusted p=0.029) were significantly more frequent in the group with alcoholism co-morbidity when compared with the group without this co-morbidity.

LIMITATIONS

Sample size and retrospective assessment of suicide behavior and psychiatric comorbidities.

CONCLUSIONS

The results obtained in our study indicate that BDNF variants may confer susceptibility to additional psychiatric diagnosis in BD.