The functioning of the hypothalamic-pituitary-adrenal (HPA) axis in postpartum depressive states: a systematic review

Comparison of CUMS at different pregnancy stages, maternal separation, and their effects on offspring in postpartum depression mouse models

Due to the diversity of postpartum depression (PPD) patients and the complexity of associated pathophysiological changes, most current animal models cannot accurately simulate PPD-like symptoms. In this study, we established a reliable animal model for PPD by inducing chronic unpredictable mild stress (CUMS) at different stages (pre-pregnancy, pregnancy, or postnatal) in female mice, followed by maternal separation (MS) from day 2-21 after delivery. The results for female mice subjected to pre-pregnancy stress were not statistically significant due to a lower conception rate. However, female mice exposed to CUMS during either the gestational or postnatal stage, followed by MS, successfully exhibited PPD-like symptoms. The models were deemed effective based on observed behavioral abnormalities, impaired hippocampal neuron functioning, and reduced serum concentrations of neurotransmitters (5-HT, GABA, and NE). Additionally, mice that underwent gestational CUMS followed by MS displayed a more dysfunctional hypothalamic-pituitary-adrenal (HPA) axis and more severe uterine inflammation. The study also investigated the impact of PPD on the behavior and neurodevelopment of adolescent offspring through behavioral tests, enzyme-linked immunosorbent assay (ELISA), hematoxylin-eosin (HE) staining, and western blotting (WB). The results indicated that adolescent offspring of mothers with PPD exhibited behavioral and neurodevelopmental disorders, with male offspring being more susceptible than females. Female mice exposed to both CUMS and MS during the postnatal period had more severe adverse effects on their offspring compared to the other model groups.

Postpartum Depression: Etiology, Treatment, and Consequences for Maternal Care

Postpartum depression (PPD) is a disabling condition that has recently shown an increase in prevalence, becoming an essential public health problem. This study is a qualitative review summarizing the most frequent risk factors associated with PPD, evaluating molecular aspects of PPD and current approaches to detect and prevent PPD. The most prevalent risk factors were detected in the areas of economic and social factors, obstetrical history, lifestyle, and history of mental illness. Research on the genetic basis for PPD has taken place in recent years to identify the genes responsible for establishing targeted therapeutic methods and understanding its pathogenesis. The most frequently studied candidate gene was the serotonin transporter gene (SERT) associated with PPD. Among biological studies, antidepressants and psychological interventions provided the most evidence of successful intervention. The obstetrician can serve an essential role in screening for and treating PPD. Postpartum women with risk factors should be screened using the Edinburgh Postnatal Depression Scale (EPDS), but, at the moment, there are no prevention programs in Europe. In conclusion, data from this review increase concerns among this vulnerable population and can be used to design a screening tool for high-risk pregnant women and create a prevention program.

Processed Polygonatum cyrtonema Hua attenuates postpartum depression in rat model by regulating monoamines and hormones

Background

Polygonatum cyrtonema Hua is a traditional Chinese medicinal food herb which can regulate the liver and Qi, nourish the heart and blood, moisten the lungs and nourish the kidneys with the potential to treat emotional diseases. However, few studies have explored the effects of Polygonatum cyrtonema Hua on postpartum depression. Therefore, we investigated whether processed Polygonatum cyrtonema Hua could improve postpartum depression in rat models by regulating monoamines and hormones.

Methods

Female Sprague-Dawley rats were randomized into normal control (0.9%Nacl), Sham operation (0.9%Nacl), postpartum depression model (0.9%Nacl), fluoxetine (2.5 mg/kg Fluoxetine), low, medium and high dose of processed Polygonatum cyrtonema Hua (2.5 g/kg, 5 g/kg, 10 g/kg) groups. Rats in these groups received drug intervention, and then subjected to Open-field test and Forced swimming test. Brain tissues and serum samples were collected and used to quantify levels of monoamines, hypothalamic-pituitary-adrenal axis and serum Estradiol. The status of neuronal cells in hippocampus 1 region was examined through hematoxylin-eosin staining, whereas expression of estrogen receptor α and β was detected by immunohistochemistry.

Results

Rats in the model group showed decreased mobility time, the disorder of neuronal cells in hippocampus 1 area, and decreased concentration of 5-hydroxytryptamine and dopamine in brain tissue, norepinephrine and estradiol in serum as well as estrogen receptor α and β expression. They also exhibited increased adrenocorticotropic hormone, corticosterone and corticotropin releasing hormone in serum. However, the treatment with processed Polygonatum cyrtonem Hua or fluoxetine reversed the above abnormalities.

Conclusion

The H group showed significant improvement in postpartum depression in rats, and processed Polygonatum cyrtonema Hua can be used as a developing drug for the prevention or treatment of depression.

Investigation of Hypothalamic Pituitary Adrenal Axis and Oxytocinergic System Changes in a Pragmatic Randomized Controlled Feasibility Trial of Acupuncture for Antenatal Depression

Background: Antenatal depression is common and associated with detrimental impacts on women and their families. Disrupted neuroendocrine functioning is reported in women experiencing perinatal mental health disturbances. Preliminary randomized controlled trial (RCT) evidence suggests acupuncture may provide a safe and effective adjunct treatment; however, underlying mechanisms of effect are unclear. We conducted an RCT examination of acupuncture for the management of antenatal depressive symptomologies, which included oxytocinergic and hypothalamic pituitary adrenal (HPA) axis system evaluations. This article reports postintervention changes to cortisol: dehydroepiandrosterone (DHEA) ratios, and oxytocin (OT) hormone concentrations. Methods: Fifty-seven women with Edinburgh Postnatal Depression Scale (EPDS) scores ≥13 were randomized to receive individually tailored depressed specific acupuncture, progressive muscle relaxation (PMR) attention comparator, or treatment as usual (TAU). Weekly 1-h sessions were conducted for 8 weeks (24-31 of pregnancy). Preintervention and postintervention saliva samples were collected. Results: Postintervention mean cortisol: DHEA ratio differences were not significantly predicted by group allocation (n = 46, p = 0.065). Two-group comparisons demonstrated cortisol: DHEA ratios were significantly increased and predicted by group allocation when acupuncture was compared to TAU (p = 0.039); however, not between acupuncture and PMR (p = 0.179), or PMR and TAU (p = 0.421). Postintervention OT concentrations were not significantly predicted by group allocation. Limitations: Small sample size and posthoc analysis Conclusion: Findings suggest positive regulation of the HPA axis may be an underlying mechanism by which acupuncture provided the significant improvements to antenatal depression, stress, and distress observed in this cohort. Trial Registration: Registered on March 19, 2015, with the Australian New Zealand Clinical Trials Registry (ACTRN12615000250538).

The role of the hypothalamic-pituitary-adrenal axis in depression across the female reproductive lifecycle: current knowledge and future directions

The aim of this narrative review is to consolidate knowledge on the role of the hypothalamic-pituitary-adrenal (HPA) axis in depression pathophysiology at different reproductive stages across the female lifespan. Despite growing evidence about the impact of gonadal hormones on mood disorders, no previous review has examined the interaction between such hormonal changes and the HPA axis within the context of depressive disorders in women. We will focus on HPA axis function in depressive disorders at different reproductive stages including the menstrual cycle (e.g., premenstrual dysphoric disorder [PMDD]), perinatally (e.g., postpartum depression), and in perimenopausal depression. Each of these reproductive stages is characterized by vast physiological changes and presents major neuroendocrine reorganization. The HPA axis is one of the main targets of such functional alterations, and with its key role in stress response, it is an etiological factor in vulnerable windows for depression across the female lifespan. We begin with an overview of the HPA axis and a brief summary of techniques for measuring HPA axis parameters. We then describe the hormonal milieu of each of these key reproductive stages, and integrate information about HPA axis function in depression across these reproductive stages, describing similarities and differences. The role of a history of stress and trauma exposure as a contributor to female depression in the context of HPA axis involvement across the reproductive stages is also presented. This review advances the pursuit of understanding common biological mechanisms across depressive disorders among women. Our overarching goal is to identify unmet needs in characterizing stress-related markers of depression in women in the context of hormonal changes across the lifespan, and to support future research in women's mental health as it pertains to pathophysiology, early diagnosis, and treatment targets.

The contributions of parental lactation on offspring development: It's not udder nonsense!

The Developmental Origins of Health and Disease (DOHaD) hypothesis describes how maternal stress exposures experienced during critical periods of perinatal life are linked to altered developmental trajectories in offspring. Perinatal stress also induces changes in lactogenesis, milk volume, maternal care, and the nutritive and non-nutritive components of milk, affecting short and long-term developmental outcomes in offspring. For instance, selective early life stressors shape the contents of milk, including macro/micronutrients, immune components, microbiota, enzymes, hormones, milk-derived extracellular vesicles, and milk microRNAs. In this review, we highlight the contributions of parental lactation to offspring development by examining changes in the composition of breast milk in response to three well-characterized maternal stressors: nutritive stress, immune stress, and psychological stress. We discuss recent findings in human, animal, and in vitro models, their clinical relevance, study limitations, and potential therapeutic significance to improving human health and infant survival. We also discuss the benefits of enrichment methods and support tools that can be used to improve milk quality and volume as well as related developmental outcomes in offspring. Lastly, we use evidence-based primary literature to convey that even though select maternal stressors may modulate lactation biology (by influencing milk composition) depending on the severity and length of exposure, exclusive and/or prolonged milk feeding may attenuate the negative in utero effects of early life stressors and promote healthy developmental trajectories. Overall, scientific evidence supports lactation to be protective against nutritive and immune stressors, but the benefits of lactation in response to psychological stressors need further investigation.

Targeting the Arginine Vasopressin V1b Receptor System and Stress Response in Depression and Other Neuropsychiatric Disorders

A healthy stress response is critical for good mental and overall health and promotes neuronal growth and adaptation, but the intricately balanced biological mechanisms that facilitate a stress response can also result in predisposition to disease when that equilibrium is disrupted. The hypothalamic-pituitary-adrenal (HPA) axis neuroendocrine system plays a critical role in the body's response and adaptation to stress, and vasopressinergic regulation of the HPA axis is critical to maintaining system responsiveness during chronic stress. However, exposure to repeated or excessive physical or emotional stress or trauma can shift the body's stress response equilibrium to a "new normal" underpinned by enduring changes in HPA axis function. Exposure to early life stress due to adverse childhood experiences can also lead to lasting neurobiological changes, including in HPA axis function. HPA axis impairment in patients with depression is considered among the most reliable findings in biological psychiatry, and chronic stress has been shown to play a major role in the pathogenesis and onset of depression and other neuropsychiatric disorders. Modulating HPA axis activity, for example via targeted antagonism of the vasopressin V_1b receptor, is a promising approach for patients with depression and other neuropsychiatric disorders associated with HPA axis impairment. Despite favorable preclinical indications in animal models, demonstration of clinical efficacy for the treatment of depressive disorders by targeting HPA axis dysfunction has been challenging, possibly due to the heterogeneity and syndromal nature of depressive disorders. Measures of HPA axis function, such as elevated cortisol levels, may be useful biomarkers for identifying patients who may benefit from treatments that modulate HPA axis activity. Utilizing clinical biomarkers to identify subsets of patients with impaired HPA axis function who may benefit is a promising next step in fine-tuning HPA axis activity via targeted antagonism of the V_1b receptor.

The Value of HPA Axis Hormones as Biomarkers for Screening and Early Diagnosis of Postpartum Depression: Updated Information About Methodology

Because of the high prevalence of postpartum depression (PPD) and the suffering involved, early diagnosis is urgent; however, current screening tools and diagnosis are inadequate. In addition to conventional methods such as the Edinburgh Postnatal Depression Scale and clinical interviews, several hormones in the hypothalamic-pituitary-adrenal (HPA) axis, such as corticotrophin-releasing hormone, adrenocorticotropic hormone, and cortisol, have been considered because of their critical roles in stress regulation in the mothers. The study designs are complicated, however, and so the effectiveness of these hormones as biomarkers for PPD is still controversial. Such inconsistency may have resulted from the variation in methodology between studies. The methodology problems in the investigation of PPD and HPA axis hormones have not been reported extensively. We therefore sought to summarize the methodological problems of studies published in the past decade, including the strengths and weaknesses of the examinations and the technological difficulties involved. Our findings suggest that (a) suitable samples and appropriate detection methods would reduce heterogeneity among trials; (b) the cutoff value of the scale test should be carefully selected for determining the performance of biomarker tests; (c) evaluation methods and criteria should be chosen with consideration of the tools feasible for use in local hospitals and population; and (d) the cost of diagnosis should be reduced. We hope that these findings provide insight for future investigations of HPA axis hormones as biomarkers for screening and early diagnosis of PPD.

Factors influencing the microbial composition of human milk

Aside from nutritional components, human milk is rich in microorganisms. Through breastfeeding these microorganisms are introduced to the infant gut where they may transiently or persistently colonize it. Therefore, the human milk microbiota may be an important factor which shapes the infant gut microbiota further influencing infant health and disease. In the current review we aim to give a brief updated insight into the putative origin of the human milk microbiota, its constituents and the possible factors that shape it. Understanding the factors that determine the human milk microbiota composition and function will aid developing optimal postnatal feeding and intervention strategies to reduce the risk of communicable and noncommunicable diseases.

The Role of HPA Axis and Allopregnanolone on the Neurobiology of Major Depressive Disorders and PTSD

Under stressful conditions, the hypothalamic-pituitary-adrenal (HPA) axis acts to promote transitory physiological adaptations that are often resolved after the stressful stimulus is no longer present. In addition to corticosteroids (e.g., cortisol), the neurosteroid allopregnanolone (3α,5α-tetrahydroprogesterone, 3α-hydroxy-5α-pregnan-20-one) participates in negative feedback mechanisms that restore homeostasis. Chronic, repeated exposure to stress impairs the responsivity of the HPA axis and dampens allopregnanolone levels, participating in the etiopathology of psychiatric disorders, such as major depressive disorder (MDD) and post-traumatic stress disorder (PTSD). MDD and PTSD patients present abnormalities in the HPA axis regulation, such as altered cortisol levels or failure to suppress cortisol release in the dexamethasone suppression test. Herein, we review the neurophysiological role of allopregnanolone both as a potent and positive GABAergic neuromodulator but also in its capacity of inhibiting the HPA axis. The allopregnanolone function in the mechanisms that recapitulate stress-induced pathophysiology, including MDD and PTSD, and its potential as both a treatment target and as a biomarker for these disorders is discussed.

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.

Light therapy for mood disorders

In this chapter, light therapy for mood disorders is discussed, including mood disorders during and after pregnancy. In the introduction, we discuss the symptomatology, etiology, and treatment of a specific type of mood disorder, seasonal affective disorder, since it kick-started the first clinical trials with light therapy. Second, we elaborate on the pathophysiology of mood disorders, in particular in the peripartum period. Next, we present an overview of the proposed working mechanisms of light therapy, followed by a discussion of the clinical trials that have followed after the initial research in seasonal affective disorder. Finally, we also focus on the limitations of these trials, such as considerable heterogeneity among studies and many methodological shortcomings. This is complemented by a number of suggestions for future research. Further studies are needed, which stems from the fact that the results have not always been consistent. Despite this, light therapy may be a promising treatment option for various types of mood disorders, since it shows a significant reduction in symptoms in many patients with few adverse effects.

Pregnancy, postpartum and parity: Resilience and vulnerability in brain health and disease

Risk and resilience in brain health and disease can be influenced by a variety of factors. While there is a growing appreciation to consider sex as one of these factors, far less attention has been paid to sex-specific variables that may differentially impact females such as pregnancy and reproductive history. In this review, we focus on nervous system disorders which show a female bias and for which there is data from basic research and clinical studies pointing to modification in disease risk and progression during pregnancy, postpartum and/or as a result of parity: multiple sclerosis (MS), depression, stroke, and Alzheimer's disease (AD). In doing so, we join others (Shors, 2016; Galea et al., 2018a) in aiming to illustrate the importance of looking beyond sex in neuroscience research.

Chronic psychosocial stress during pregnancy affects maternal behavior and neuroendocrine function and modulates hypothalamic CRH and nuclear steroid receptor expression

Postpartum depression (PPD) affects up to 20% of mothers and has negative consequences for both mother and child. Although exposure to psychosocial stress during pregnancy and abnormalities in the hypothalamic pituitary adrenal (HPA) axis have been linked to PPD, molecular changes in the brain that contribute to this disease remain unknown. This study utilized a novel chronic psychosocial stress paradigm during pregnancy (CGS) to investigate the effects of psychosocial stress on maternal behavior, neuroendocrine function, and gene expression changes in molecular regulators of the HPA axis in the early postpartum period. Postpartum female mice exposed to CGS display abnormalities in maternal behavior, including fragmented and erratic maternal care patterns, and the emergence of depression and anxiety-like phenotypes. Dysregulation in postpartum HPA axis function, evidenced by blunted circadian peak and elevation of stress-induced corticosterone levels, was accompanied by increased CRH mRNA expression and a reduction in CRH receptor 1 in the paraventricular nucleus of the hypothalamus (PVN). We further observed decreased PVN expression of nuclear steroid hormone receptors associated with CRH transcription, suggesting these molecular changes could underlie abnormalities in postpartum HPA axis and behavior observed. Overall, our study demonstrates that psychosocial stress during pregnancy induces changes in neuroendocrine function and maternal behavior in the early postpartum period and introduces our CGS paradigm as a viable model that can be used to further dissect the molecular defects that lead to PPD.

Neurophysiological and cognitive changes in pregnancy

The hormonal fluctuations in pregnancy drive a wide range of adaptive changes in the maternal brain. These range from specific neurophysiological changes in the patterns of activity of individual neuronal populations, through to complete modification of circuit characteristics leading to fundamental changes in behavior. From a neurologic perspective, the key hormone changes are those of the sex steroids, estradiol and progesterone, secreted first from the ovary and then from the placenta, the adrenal glucocorticoid cortisol, as well as the anterior pituitary peptide hormone prolactin and its pregnancy-specific homolog placental lactogen. All of these hormones are markedly elevated during pregnancy and cross the blood-brain barrier to exert actions on neuronal populations through receptors expressed in specific regions. Many of the hormone-induced changes are in autonomic or homeostatic systems. For example, patterns of oxytocin and prolactin secretion are dramatically altered to support novel physiological functions. Appetite is increased and feedback responses to metabolic hormones such as leptin and insulin are suppressed to promote a positive energy balance. Fundamental physiological systems such as glucose homeostasis and thermoregulation are modified to optimize conditions for fetal development. In addition to these largely autonomic changes, there are also changes in mood, behavior, and higher processes such as cognition. This chapter summarizes the hormonal changes associated with pregnancy and reviews how these changes impact on brain function, drawing on examples from animal research, as well as available information about human pregnancy.

Preterm birth as a risk factor for postpartum depression: A systematic review and meta-analysis

BACKGROUND

This systematic review aimed to critically analyze the studies that explored preterm birth as risk factor for postpartum depression in the last 10 years.

METHODS

Two independent researchers performed a systematic review of indexed studies in PubMed/Medline, Web of Science and PsycInfo database. The PRISMA for reporting systematic review model was used to conduct data extraction. A meta-analysis was performed including a sub-group of studies.

RESULTS

The final sample consisted of 26 studies and 12 were included in the meta-analysis. Most of the studies supported the association between preterm birth (PTB) and postpartum depression (PPD). However, 8 studies did not find such association and, even among studies with positive findings, results were heterogeneous, given the methodological discrepancies among the studies. The meta-analysis provided evidence of higher risk for PPD among mothers of preterm infants in assessments performed up to 24 weeks after childbirth.

LIMITATIONS

Most of the studies did not consider the role of important confounding variables, such as previous history of depression. Heterogeneity of assessment tools and cut-off scores were also considered a limitation.

CONCLUSIONS

Further prospective population-based studies with an integrative approach of PPD are needed to provide consistent evidence of such association. Important confounding variables and biological measures implicated in PPD should be considered. Our findings highlight the importance of maternal mental health care in this target population, as preterm birth experience seem to affect both babies and mothers. We encourage PPD assessment for mothers of preterm infants, especially in the early postpartum period.

Human Milk Microbiome and Maternal Postnatal Psychosocial Distress

Human milk contains many bioactive components, including bacteria, which are transferred to the developing infant through breastfeeding. Milk bacteria appear to, amongst others, originate from the maternal gut. A mother’s postnatal psychosocial distress may alter maternal gut microbiota, which in turn may affect the bacteria present in milk. The aim of this study was to explore whether maternal postnatal psychosocial distress was related to alterations in the relative abundances of specific bacteria and to milk microbial diversity. Healthy mothers (N = 77; N = 51 with complete data) collected breast milk samples at 2, 6, and 12 weeks postpartum and filled in mood questionnaires on experienced stress, anxiety, and depressive symptoms at 6 weeks postpartum. A metataxonomic approach (16S rRNA gene sequencing (region V3 and V4) using Illumina MiSeq technology) was used to assess bacterial abundances and diversity. For the group as a whole, an increase in diversity of the milk bacterial community was observed during the first 3 months of breastfeeding (Shannon index). This general increase in diversity appears to be explained by an increase of Lactobacillus and other minor genera, together with a decrease in Staphylococcus. With respect to psychological distress and milk microbial composition, no significant differences in the relative abundance of major bacterial genera were detected between women with high (N = 13) and low (N = 13) psychosocial distress. However, progressive and distinct changes in the content of Firmicutes, Proteobacteria, and Bacteroidetes at the phylum level and Acinetobacter, Flavobacterium, and Lactobacillus at the genera level were observed in milk samples of women with low psychosocial distress. With respect to milk microbial diversity, high maternal psychosocial distress, compared to low maternal psychosocial distress, was related to significantly lower bacterial diversity in milk at 3 months post-delivery. Anxiety, stress, and depressive symptoms separately were unrelated to specific bacterial profiles. The current study suggests a potential relation between maternal psychosocial distress and milk microbiota, providing first evidence of a possible mechanism through which post-partum psychological symptoms may affect infant development and health.

Withdrawal of plasma estradiol is associated with increased anxiety reported by women in the first 12 hours after delivery

The aim of this study was to verify if the fall of plasma concentrations of steroid hormones in the first 12 h postpartum would be associated with changes in the same period in the emotional state of healthy women. Subjective and hormonal data were collected from 14 women (28.5 ± 7.1 years old) at zero (only hormones), 1, 2, 6 and 12 h after delivery. Subjective measures were taken using the Visual Analogue Mood Scale (VAMS), which consists of four factors (anxiety, sedation, discomfort, and cognitive impairment). Cortisol was measured by radioimmunoassay and estradiol and progesterone by chemiluminescence immunoassay. Women reported a significant increase in anxiety (relative increase: 43.8%±77.6) and discomfort (125.9%±218.5) within the 12 h postpartum. There were also significant decreases in the plasma concentration of estradiol (relative decrease: 96.5%±3.1), progesterone (78.1%±8.7) and cortisol (71.7%±18.0). The relative decrease in estradiol concentrations was significantly correlated with the relative increase in anxiety. No significant associations between progesterone and cortisol concentrations and subjective measures were observed. Changes of estradiol but not of progesterone and cortisol concentrations were associated with changes in the reported emotional state of healthy women in the immediate postpartum period. The role of this association as a predictor of mood disorders in the postpartum period should be explored in further studies.