Multifunctional aspects of allopregnanolone in stress and related disorders

Antidepressant effects of activation of infralimbic cortex via upregulation of BDNF and β-catenin in an estradiol withdrawal model

RATIONALE

Clinical and preclinical studies have demonstrated that estradiol withdrawal after delivery is one of important factors involved in the pathogenesis of postpartum depression (PPD). The infralimbic cortex (IL) is related to anxiety and mood disorders. Whether IL neurons mediate PPD is still unclear.

OBJECTIVES

This study was to observe the antidepressant effect and expression of BDNF and β-catenin in IL by allopregnanolone (ALLO) treatment or the selective activation or inhibition of IL neurons using a chemogenetic approach in a pseudopregnancy model of PPD.

METHODS

Administration of estradiol combined with progesterone and the abrupt withdrawal of estradiol simulated the pregnancy and early postpartum periods to induce depression in ovariectomized rats. The relative expression levels of β-catenin and BDNF were observed by western blotting.

RESULTS

Immobility time was significantly increased in the forced swim test and open-arm movement was reduced in the elevated plus maze test in the estradiol-withdrawn rats. After ALLO treatment, the immobility time were lower and open-arm traveling times higher than those of the estradiol-withdrawn rats. Meanwhile, the expression level of BDNF or β-catenin in the IL was reduced significantly in estradiol-withdrawn rats, which was prevented by treatment with ALLO. The hM3Dq chemogenetic activation of pyramidal neurons in the IL reversed the immobility and open-arm travel time trends in the estradiol-withdrawal rat model, but chemogenetic inhibition of IL neurons failed to affect this. Upregulated BDNF and β-catenin expression and increased c-Fos in the basolateral amygdala were found following IL neuron excitation in model rats.

CONCLUSIONS

Our results demonstrated that pseudopregnancy and estradiol withdrawal produced depressive-like behavior and anxiety. ALLO treatment or specific excitement of IL pyramidal neurons relieved abnormal behaviors and upregulated BDNF and β-catenin expression in the IL in the PPD model, suggesting that hypofunction of IL neurons may be involved in the pathogenesis of PPD.

Mitochondrial might: powering the peripartum for risk and resilience

The peripartum period, characterized by dynamic hormonal shifts and physiological adaptations, has been recognized as a potentially vulnerable period for the development of mood disorders such as postpartum depression (PPD). Stress is a well-established risk factor for developing PPD and is known to modulate mitochondrial function. While primarily known for their role in energy production, mitochondria also influence processes such as stress regulation, steroid hormone synthesis, glucocorticoid response, GABA metabolism, and immune modulation - all of which are crucial for healthy pregnancy and relevant to PPD pathology. While mitochondrial function has been implicated in other psychiatric illnesses, its role in peripartum stress and mental health remains largely unexplored, especially in relation to the brain. In this review, we first provide an overview of mitochondrial involvement in processes implicated in peripartum mood disorders, underscoring their potential role in mediating pathology. We then discuss clinical and preclinical studies of mitochondria in the context of peripartum stress and mental health, emphasizing the need for better understanding of this relationship. Finally, we propose mitochondria as biological mediators of resilience to peripartum mood disorders.

Zuranolone - synthetic neurosteroid in treatment of mental disorders: narrative review

With each passing year, the number of people suffering from mental disorders grows at a disturbing speed. Neuroactive steroids are a new promising group of drugs with the potential for use in many diseases like postpartum depression, postnatal psychosis, major depression, insomnia, bipolar disorder, and Parkinson's tremor, due to their ability to modulate the activity of GABAA receptor. Neurosteroids are progesterone metabolites that are synthesized from cholesterol or steroid hormones in various brain regions. They regulate neuronal development, regeneration, and neurotransmission. They are implicated in mood disorders, anxiety disorders, schizophrenia, PTSD, and impulsive aggression. Neurosteroids have been studied for their potential to prevent or treat neurodegenerative diseases such as Alzheimer's disease and HIV-associated dementia. They can promote neurogenesis, neuronal survival, myelination, and memory function. They can also affect the growth and sensitivity of hormone-dependent brain tumors such as gliomas. Zuranolone, a newly registered neurosteroid drug has shown huge flexibility in both clinical and ambulatory treatment thanks to its pharmacokinetic traits, especially the possibility for oral administration, unlike its predecessor Brexanolone. Zuranolone is a synthetic positive allosteric modulator of the GABAA receptor that can be taken orally. The review aims to summarize the current knowledge on zuranolone as a novel neurosteroid drug for various mental disorders, especially for postpartum mental disorders for which this drug was meant originally. It covers studies indexed in the PubMed, Scopus, and Web of Science databases published since 2017. Keywords used in the search, as well as inclusion and exclusion criteria, are given in the aims and methodology section. The review explains the evidence for the role of neurosteroids, especially allopregnanolone, in the pathophysiology and treatment of postpartum depression. It discusses the mechanisms of neurosteroid action, the changes in neurosteroid levels during pregnancy and postpartum, and the clinical trials of brexanolone and zuranolone, two synthetic analogs of allopregnanolone, for postpartum depression. It provides an overview of the biosynthesis and metabolism of neurosteroids in the central and peripheral nervous system. Furthermore, it explains the different sources and pathways of neurosteroid production and the factors that influence their synthesis and regulation, such as stress, hormones, drugs, and genetic variations. The review also explores the potential relevance of neurosteroids for other psychiatric disorders, such as major depression, bipolar disorder, post-traumatic stress disorder (PTSD), schizophrenia, and premenstrual dysphoric disorder. Finally, it highlights the associations between neurosteroid levels and symptom severity and the effects of neurosteroid modulation on mood, cognition, and neuroplasticity.

Gestational stress decreases postpartum mitochondrial respiration in the prefrontal cortex of female rats

Postpartum depression (PPD) is a major psychiatric complication of childbirth, affecting up to 20% of mothers, yet remains understudied. Mitochondria, dynamic organelles crucial for cell homeostasis and energy production, share links with many of the proposed mechanisms underlying PPD pathology. Brain mitochondrial function is affected by stress, a major risk factor for development of PPD, and is linked to anxiety-like and social behaviors. Considering the importance of mitochondria in regulating brain function and behavior, we hypothesized that mitochondrial dysfunction is associated with behavioral alterations in a chronic stress-induced rat model of PPD. Using a validated and translationally relevant chronic mild unpredictable stress paradigm during late gestation, we induced PPD-relevant behaviors in adult postpartum Wistar rats. In the mid-postpartum, we measured mitochondrial function in the prefrontal cortex (PFC) and nucleus accumbens (NAc) using high-resolution respirometry. We then measured protein expression of mitochondrial complex proteins and 4-hydroxynonenal (a marker of oxidative stress), and Th1/Th2 cytokine levels in PFC and plasma. We report novel findings that gestational stress decreased mitochondrial function in the PFC, but not the NAc of postpartum dams. However, in groups controlling for the effects of either stress or parity alone, no differences in mitochondrial respiration measured in either brain regions were observed compared to nulliparous controls. This decrease in PFC mitochondrial function in stressed dams was accompanied by negative behavioral consequences in the postpartum, complex-I specific deficits in protein expression, and increased Tumor Necrosis Factor alpha cytokine levels in plasma and PFC. Overall, we report an association between PFC mitochondrial respiration, PPD-relevant behaviors, and inflammation following gestational stress, highlighting a potential role for mitochondrial function in postpartum health.

Exploring Novel Therapeutic Approaches for Depressive Disorders: The Role of Allopregnanolone Agonists

Depressive disorders are caused due to the impaired functioning of important brain networks. Recent studies have also shown that it is caused by a significant reduction in the levels of allopregnanolone, which is a progesterone metabolite. Newer treatment modalities are now focusing on the usage of neuroactive steroids, such as allopregnanolone, in various depressive disorders. Our aim was to provide a comprehensive literature review on the clinical aspects of the allopregnanolone agonists brexanolone and zuranolone with reference to the physiological role of allopregnanolone. Brexanolone was approved by the FDA in 2019 for the treatment of postpartum depression and has greatly influenced further research into potential drugs such as zuranolone, which is currently undergoing phase 3 of clinical trials. Although these drugs exhibit improvement in symptoms of depressive disorders along with notable side effects, further research is required for their future clinical use.

Validation of an ELISA kit to measure allopregnanolone in human and equine hair

In humans, allopregnanolone plays important roles in a number of different neurodegenerative disorders, and it has been proposed for use in some therapies. Horses are commonly used as animal models for human neurodegenerative diseases, mental and behavioral disorders, and neuropsychiatric disorders, and there is interest in using hair as a biological sample to study hormones in these conditions. We validated the use of a commercial ELISA kit (DetectX allopregnanolone kit; Arbor Assays), which was designed for serum, plasma, feces, urine, and tissue samples, to assess allopregnanolone in hair samples from 30 humans and 63 horses. The ELISA kit had good precision (intra- and inter-assay CVs: 6.4% and 11.0% for equine hair; 7.3% and 11.0% for human hair, respectively), sensitivity (50.4 pg/mL for both equine and human hair), and accuracy (parallelism and recovery tests) in determining allopregnanolone concentrations in hair from both species. The allopregnanolone concentrations in human hair were 7.3-79.1 pg/mg; the concentrations were 286 ± 141 pg/mg (x̄ ± SD) in mares on the day of parturition and 16.9 ± 5.5 pg/mg in nonpregnant mares. The DetectX ELISA kit offered a simple and accessible analysis of allopregnanolone in human and equine hair samples.

Biological Mechanisms in Pregnant Women With Anxiety (Happy Mother-Healthy Baby Supplement Study): Protocol for a Longitudinal Mixed Methods Observational Study

BACKGROUND

Anxiety and depression are common in the perinatal period and negatively affect the health of the mother and baby. Our group has developed "Happy Mother-Healthy Baby" (HMHB), a cognitive behavioral therapy-based psychosocial intervention to address risk factors specific to anxiety during pregnancy in low- and middle-income countries (LMICs).

OBJECTIVE

The purpose of this study is to examine biological mechanisms that may be linked to perinatal anxiety in conjunction with a randomized controlled trial of HMHB in Pakistan.

METHODS

We are recruiting 120 pregnant women from the Holy Family Hospital, a public facility in Rawalpindi, Pakistan. Participants are assessed for at least mild anxiety symptoms using the Hospital Anxiety and Depression Scale (ie, a score ≥8 on the anxiety scale is necessary for inclusion in the anxiety groups and <8 for inclusion in the healthy control group). Women who meet the criteria for an anxiety group are randomized into either the HMHB intervention group or an enhanced usual care (EUC) control group. Participants receive HMHB or EUC throughout pregnancy and undergo blood draws at 4 time points (baseline, second trimester, third trimester, and 6 weeks post partum). We will assess peripheral cytokine concentrations using a multiplex assay and hormone concentrations using gas chromatography and mass spectrometry. The statistical analysis will use generalized linear models and mixed effects models to assess the relationships across time among anxiety, immune dysregulation, and hormone levels, and to assess whether these biological factors mediate the relationship between anxiety and birth and child development outcomes.

RESULTS

Recruitment started on October 20, 2020, and data collection was completed on August 31, 2022. The start date for recruitment for this biological supplement study was delayed by approximately half a year due to the COVID-19 pandemic. The trial was registered at ClinicalTrials.gov (NCT03880032) on September 22, 2020. The last blood samples were shipped to the United States on September 24, 2022, where they will be processed for analysis.

CONCLUSIONS

This study is an important addition to the HMHB randomized controlled trial of an intervention for antenatal anxiety. The intervention itself makes use of nonspecialist providers and, if effective, will represent an important new tool for the treatment of antenatal anxiety in LMICs. Our biological substudy is one of the first attempts to link biological mechanisms to antenatal anxiety in an LMIC in the context of a psychosocial intervention, and our findings have the potential to significantly advance our knowledge of the biological pathways of perinatal mental illness and treatment efficacy.

TRIAL REGISTRATION

ClinicalTrials.gov NCT03880032; https://clinicaltrials.gov/ct2/show/NCT03880032.

INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID)

DERR1-10.2196/43193.

White Matter Microstructure Is Associated with Serum Neuroactive Steroids and Psychological Functioning

Military service members are at increased risk for mental health issues, and comorbidity with mild traumatic brain injury (mTBI) is common. Largely overlapping symptoms between conditions suggest a shared pathophysiology. The present work investigates the associations among white matter microstructure, psychological functioning, and serum neuroactive steroids that are part of the stress-response system. Diffusion-weighted brain imaging was acquired from 163 participants (with and without military affiliation) and free-water-corrected fractional anisotropy (FAT) was extracted. Associations between serum neurosteroid levels of allopregnanolone (ALLO) and pregnenolone (PREGNE), psychological functioning, and whole-brain white matter microstructure were assessed using regression models. Moderation models tested the effect of mTBI and comorbid post-traumatic stress disorder (PTSD) and mTBI on these associations. ALLO is associated with whole-brain white matter FAT (β = 0.24, t = 3.05, p = 0.006). This association is significantly modulated by PTSD+mTBI comorbidity (β = 0.00, t = 2.50, p = 0.027), although an mTBI diagnosis alone did not significantly impact this association (p = 0.088). There was no significant association between PREGNE and FAT (p = 0.380). Importantly, lower FAT is associated with poor psychological functioning (β = -0.19, t = -2.35, p = 0.020). This study provides novel insight into a potential common pathophysiological mechanism of neurosteroid dysregulation underlying the high risk for mental health issues in military service members. Further, comorbidity of PTSD and mTBI may bring the compensatory effects of the brain's stress response to their limit. Future research is needed to investigate whether neurosteroid regulation may be a promising tool for restoring brain health and improving psychological functioning.

A focus on Rho/ROCK signaling pathway: An emerging therapeutic target in depression

Depression is the most common mental health disorder worldwide; however, the exact cellular and molecular mechanisms of this major depressive disorder are unclear so far. Experimental studies have demonstrated that depression is associated with significant cognitive impairment, dendrite spine loss, and reduction in connectivity among neurons that contribute to symptoms associated with mood disorders. Rho/Rho-associated coiled-coil containing protein kinase (ROCK) receptors are exclusively expressed in the brain and Rho/ROCK signaling has gained considerable attention as it plays a crucial role in the development of neuronal architecture and structural plasticity. Chronic stress-induced activation of the Rho/ROCK signaling pathway promotes neuronal apoptosis and loss of neural processes and synapses. Interestingly, accumulated evidence has identified Rho/ROCK signaling pathways as a putative target for treating neurological disorders. Furthermore, inhibition of the Rho/ROCK signaling pathway has proven to be effective in different models of depression, which signify the potential benefits of clinical Rho/ROCK inhibition. The ROCK inhibitors extensively modulate antidepressant-related pathways which significantly control the synthesis of proteins, and neuron survival and ultimately led to the enhancement of synaptogenesis, connectivity, and improvement in behavior. Therefore, the present review refines the prevailing contribution of this signaling pathway in depression and highlighted preclinical shreds of evidence for employing ROCK inhibitors as disease-modifying targets along with possible underlying mechanisms in stress-associated depression.

Altered visual cortex excitability in premenstrual dysphoric disorder: Evidence from magnetoencephalographic gamma oscillations and perceptual suppression

Premenstrual dysphoric disorder (PMDD) is a psychiatric condition characterized by extreme mood shifts during the luteal phase of the menstrual cycle (MC) due to abnormal sensitivity to neurosteroids and unbalanced neural excitation/inhibition (E/I) ratio. We hypothesized that in women with PMDD in the luteal phase, these factors would alter the frequency of magnetoencephalographic visual gamma oscillations, affect modulation of their power by excitatory drive, and decrease perceptual spatial suppression. Women with PMDD and control women were examined twice-during the follicular and luteal phases of their MC. We recorded visual gamma response (GR) while modulating the excitatory drive by increasing the drift rate of the high-contrast grating (static, 'slow', 'medium', and 'fast'). Contrary to our expectations, GR frequency was not affected in women with PMDD in either phase of the MC. GR power suppression, which is normally associated with a switch from the 'optimal' for GR slow drift rate to the medium drift rate, was reduced in women with PMDD and was the only GR parameter that distinguished them from control participants specifically in the luteal phase and predicted severity of their premenstrual symptoms. Over and above the atypical luteal GR suppression, in both phases of the MC women with PMDD had abnormally strong GR facilitation caused by a switch from the 'suboptimal' static to the 'optimal' slow drift rate. Perceptual spatial suppression did not differ between the groups but decreased from the follicular to the luteal phase only in PMDD women. The atypical modulation of GR power suggests that neuronal excitability in the visual cortex is constitutively elevated in PMDD and that this E/I imbalance is further exacerbated during the luteal phase. However, the unaltered GR frequency does not support the hypothesis of inhibitory neuron dysfunction in PMDD.

The relationship of potential biomarkers with psychological resilience and post-traumatic growth in female patients with breast cancer

While investigating psychosocial factors on resilience and post-traumatic growth draws attention, research on biological correlates is limited. We investigated the relationship between post-traumatic growth, resilience, post-traumatic stress, and potential biomarkers in female patients with breast cancer (n = 71) from the general surgery or oncology clinics. They completed the Post-Traumatic Growth Inventory (PTGI), Connor Davidson Psychological Resilience Scale (CD-RISC), Brief Resilience Scale (BRS), PTSD Checklist for DSM-V, and Hospital Anxiety and Depression Scale. Blood samples were collected for NPY, ALLO, DHEA-S, testosterone, cortisol, and hsCRP levels. The relationship between biochemical parameters and the scales was investigated in the whole patient group and in the subgroup of patients who perceived breast cancer as traumatic. When all the patients were evaluated, hsCRP and depression scores were significantly and positively correlated; and hsCRP, BRS score, and PTGI change in self-perception subscale score were significantly and negatively correlated. There was a significant positive correlation between the ALLO level and the psychological resilience (CD-RISC) score in the patient group who perceived breast cancer as traumatic. It was observed that psychological resilience and PTG were positively correlated, and that multiple biomarkers were associated with psychological resilience in female breast cancer patients. Especially findings regarding ALLO levels and psychological resilience could be a new target for future research.

A Nested Case-Control Study of Allopregnanolone and Preterm Birth in the Healthy Start Cohort

Context

Chronic stress is a risk factor for preterm birth; however, objective measures of stress in pregnancy are limited. Maternal stress biomarkers may fill this gap. Steroid hormones and neurosteroids such as allopregnanolone (ALLO) play important roles in stress physiology and pregnancy maintenance and therefore may be promising for preterm birth prediction.

Objective

We evaluated maternal serum ALLO, progesterone, cortisol, cortisone, pregnanolone, and epipregnanolone twice in gestation to evaluate associations with preterm birth.

Methods

We performed a nested case-control study using biobanked fasting serum samples from the Healthy Start prebirth cohort. We included healthy women with a singleton pregnancy and matched preterm cases with term controls (1:1; N = 27 per group). We used a new HPLC-tandem mass spectrometry assay to quantify ALLO and five related steroids. We used ANOVA, Fisher exact, χ², t test, and linear and logistic regression as statistical tests.

Results

Maternal serum ALLO did not associate with preterm birth nor differ between groups. Mean cortisol levels were significantly higher in the preterm group early in pregnancy (13w0d-18w0d; P < 0.05) and higher early pregnancy cortisol associated with increased odds of preterm birth (at 13w0d; odds ratio, 1.007; 95% CI, 1.0002-1.014). Progesterone, cortisone, pregnanolone, and epipregnanolone did not associate with preterm birth.

Conclusion

The findings from our pilot study suggest potential utility of cortisol as a maternal serum biomarker for preterm birth risk assessment in early pregnancy. Further evaluation using larger cohorts and additional gestational timepoints for ALLO and the other analytes may be informative.

Allopregnanolone: Regenerative therapeutic to restore neurological health

Chronic stress has been proposed as a driver of altered brain structure and function, including the pathogenesis of neurodegenerative diseases and a driver of disease progression. A key outcome of stress in the brain is structural remodeling of neural architecture, which may be a sign of successful adaptation, whereas persistence of these changes when stress ends indicate failed resilience. Neuroendocrine homeostasis and stress response are mainly dependent upon the functioning of the hypothalamic-pituitary-adrenal axis. Neurosteroids will fluctuate depending on whether the stress is acute or chronic. Advancements in neurosteroid research have led to the identification of multiple targets for drug development, but the most promising innovative target may be neurogenesis, given its potential impact in neurodegenerative disorders like Alzheimer's disease. Allopregnanolone is an endogenous pregnane neurosteroid and a reduced metabolite of progesterone, which acts as a potent allosteric modulator and direct activator of the GABA-chloride channel complex. Perhaps the most intriguing finding related to the potential therapeutic effects of allopregnanolone is its potential to promote neuroregeneration.

Effect of progesterone administration in male and female smokers on nicotine withdrawal and neural response to smoking cues: role of progesterone conversion to allopregnanolone

BACKGROUND

Progesterone administration has therapeutic effects in tobacco use disorder (TUD), with females benefiting more than males. Conversion of progesterone to the neurosteroid allopregnanolone is hypothesized to partly underlie the therapeutic effects of progesterone; however, this has not been investigated clinically.

METHODS

Smokers (n = 18 males, n = 21 females) participated in a randomized, double-blind, placebo-controlled crossover study of 200 mg progesterone daily across 4 days of abstinence. The ratio of allopregnanolone:progesterone was analyzed in relationship to nicotine withdrawal, smoking urges, mood states, subjective nicotine effects, and neural response to smoking cues.

RESULTS

Allopregnanolone:progesterone ratio interacted with sex to predict withdrawal symptoms (p = 0.047), such that females with higher allopregnanolone:progesterone ratios reported lower withdrawal severity (b = - 0.98 [- 1.95, - 0.01]; p = 0.048). In addition, allopregnanolone:progesterone ratio interacted with sex to predict confusion (p = 0.014) and fatigue (p = 0.034), such that females with higher allopregnanolone:progesterone ratios reported less confusion (b = - 0.45 [- 0.78, - 0.12]; p = 0.008) and marginally lower fatigue (b = - 0.50 [- 1.03, 0.02]; p = 0.062. Irrespective of sex, higher ratios of allopregnanolone:progesterone were associated with stronger "good effects" of nicotine (b = 8.39 [2.58, 14.20]); p = 0.005) and weaker "bad effects" of nicotine (b = - 7.13 [- 13.53, - 0.73]; p = 0.029).

CONCLUSIONS

Conversion of progesterone to allopregnanolone correlated with smoking-related outcomes in both sex-dependent and sex-independent ways. Sex-dependent effects suggest that conversion of progesterone to allopregnanolone may contribute to greater therapeutic benefits in females but not males with TUD. Trial registration Clinicaltrials.gov registration, retrospectively registered: NCT01954966; https://clinicaltrials.gov/ct2/show/NCT01954966 \.

Allopregnanolone: An overview on its synthesis and effects

Allopregnanolone, a 3α,5α-progesterone metabolite, acts as a potent allosteric modulator of the γ-aminobutyric acid type A receptor. In the present review, the synthesis of this neuroactive steroid occurring in the nervous system is discussed with respect to physiological and pathological conditions. In addition, its physiological and neuroprotective effects are also reported. Interestingly, the levels of this neuroactive steroid, as well as its effects, are sex-dimorphic, suggesting a possible gender medicine based on this neuroactive steroid for neurological disorders. However, allopregnanolone presents low bioavailability and extensive hepatic metabolism, limiting its use as a drug. Therefore, synthetic analogues or a different therapeutic strategy able to increase allopregnanolone levels have been proposed to overcome any pharmacokinetic issues.

Review of Allopregnanolone Agonist Therapy for the Treatment of Depressive Disorders

Objective

This paper reviews the current literature available for the efficacy and safety of allopregnanolone agonists and discusses considerations for their place in therapy.

Literature Search

A literature search was conducted utilizing PubMed, clinicaltrials.gov, and the manufacturer's website.

Data Synthesis

One phase II trial and two phase III trials evaluating the efficacy and safety of brexanolone were identified. Brexanolone demonstrated efficacy through significantly reduced Hamilton Depression Rating Scale (HAM-D) scores compared to placebo in the treatment of postpartum depression (PPD). Noted adverse effects were somnolence and dizziness, excessive sedation, and loss of consciousness. One published phase II study and the interim results of two phase III trials and one phase II trial on zuranolone were included in this review. Zuranolone, an oral allopregnanolone agonist, is given as a single, 14-day course. A significant reduction in HAM-D scores was demonstrated in patients with major depressive disorder (MDD) at 15 and 28 days compared to placebo. Interim results for zuranolone in PPD and bipolar disorder (BPD) show promising reductions in HAM-D scores. Adverse effects included sedation, dizziness, and headache.

Place in Therapy

Allopregnanolone agonists seem to have a role in PPD when weighing the quick onset of action and potential risks of untreated PPD. The class of medications is limited by the single course for this indication and may fit as a bridge to maintenance therapy with selective serotonin reuptake inhibitors (SSRIs). Brexanolone, specifically, is hindered by the long infusion time, hospitalization associated with administration, and risk evaluation and mitigation strategy program. Zuranolone may also have a role in MDD or BPD, but more data are needed.

Conclusion

Allopregnanolone agonists present a novel mechanism of action in the treatment of depressive disorders. Clinical trials and interim results support significant reductions in depression scores for brexanolone in PPD, and for zuranolone in PPD, MDD, and BPD.

Neurosteroidogenic enzymes: CYP11A1 in the central nervous system

Neurosteroids, steroid hormones synthesized locally in the nervous system, have important neuromodulatory and neuroprotective effects in the central nervous system. Progress in neurosteroid research has led to the successful translation of allopregnanolone into an approved therapy for postpartum depression. However, there is insufficient evidence to support the assumption that steroidogenesis is exactly the same between the nervous system and the periphery. This review focuses on CYP11A1, the only enzyme currently known to catalyze the first reaction in steroidogenesis to produce pregnenolone, the precursor to all other steroids. Although CYP11A1 mRNA has been found in brain of many mammals, the presence of CYP11A1 protein has been difficult to detect, particularly in humans. Here, we highlight the discrepancies in the current evidence for CYP11A1 in the central nervous system and propose new directions for understanding neurosteroidogenesis, which will be crucial for developing neurosteroid-based therapies for the future.

Prenatal Exposure to Bisphenols and Phthalates and Postpartum Depression: The Role of Neurosteroid Hormone Disruption

CONTEXT

Postpartum depression (PPD) is a serious psychiatric disorder. While causes remain poorly understood, perinatal sex hormone fluctuations are an important factor, and allopregnanolone in particular has emerged as a key determinant. Although synthetic environmental chemicals such as bisphenols and phthalates are known to affect sex hormones, no studies have measured allopregnanolone and the consequences of these hormonal changes on PPD have not been interrogated.

OBJECTIVE

To investigate associations of repeated measures of urinary bisphenols and phthalates in early and midpregnancy with serum pregnenolone, progesterone, allopregnanolone, and pregnanolone concentrations in midpregnancy and PPD symptoms at 4 months postpartum.

METHODS

Prospective cohort study of 139 pregnant women recruited between 2016 and 2018. Bisphenols and phthalates were measured in early and midpregnancy urine samples. Serum sex steroid hormone concentrations were measured in midpregnancy. PPD was assessed at 4 months postpartum using the Edinburgh Postnatal Depression Scale (EPDS). Multiple informant models were fit using generalized estimating equations. Serum levels of allopregnanolone, progesterone, pregnanolone, and pregnenolone were examined as log-transformed continuous variables. PPD symptoms were examined as continuous EPDS scores and dichotomously with scores ≥10 defined as PPD.

RESULTS

Di-n-octyl phthalate (DnOP) and diisononyl phthalate (DiNP) metabolites were associated with reduced progesterone concentrations. Log-unit increases in ∑DnOP and ∑DiNP predicted 8.1% (95% CI -15.2%, -0.4%) and 7.7% (95% CI -13.3%, -1.7%) lower progesterone, respectively. ∑DnOP was associated with increased odds of PPD (odds ratio 1.48; 95% CI 1.04, 2.11).

CONCLUSION

Endocrine disrupting chemicals may influence hormonal shifts during pregnancy as well as contribute to PPD.

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.

Risk of Depression Associated With Finasteride Treatment

BACKGROUND

Finasteride is one of several inhibitors of the 5α-reductase that converts testosterone to dihydrotestosterone used to treat hair loss and benign prostatic enlargement. Emerging clinical observations indicate that such treatment may be associated with depression, anxiety, and possibly increased suicidal risks, in addition to sexual dysfunction, even after its discontinuation.

METHODS

We carried out a systematic review of reports pertaining to association of finasteride treatment with clinical depression or other adverse psychiatric effects. We analyzed reported risks of depression by pooling of rates and by meta-analysis of comparisons of subjects treated with finasteride or not.

FINDINGS

Crude pooled rates of depressive symptoms with versus without finasteride were 3.33% (confidence interval, 3.22%-3.44%) versus 2.54% (2.44%-2.64%); random-effects meta-analysis yielded an odds ratio of 2.14 (1.40-3.27) (both P < 0.0001). In addition, risk of suicidal ideation or behavior was greater with versus without finasteride (21.2% [21.0%-21.5%] vs 14.0% [13.8%-14.2%], P < 0.0001), and risk of sustained sexual dysfunction was high (60.1% [37.3%-82.9%]).

CONCLUSIONS

The findings support a growing impression that finasteride is associated with adverse psychiatric effects that can persist in association with sexual dysfunction after discontinuing finasteride treatment.

Endocrinological effects of social exclusion and inclusion: Experimental evidence for adaptive regulation of female fecundity

When current conditions are probabilistically less suitable for successful reproduction than future conditions, females may prevent or delay reproduction until conditions improve. Throughout human evolution, social support was likely crucial to female reproductive success. Women may thus have evolved fertility regulation systems sensitive to cues from the social environment. However, current understanding of how psychological phenomena might affect female ovarian function is limited. In this study, we examined whether cues of reduced social support-social ostracism-impact women's hormone production. Following an in-lab group bonding task, women were randomly assigned to a social exclusion (n = 88) or social inclusion (n = 81) condition. After social exclusion, women with low background levels of social support experienced a decrease in estradiol relative to progesterone. In contrast, socially-included women with low background social support experienced an increase in estradiol relative to progesterone. Hormonal changes in both conditions occurred specifically when women were in their mid-to-late follicular phase, when baseline estradiol is high and progesterone is low. Follow-up analyses revealed that these changes were primarily driven by changes in progesterone, consistent with existing evidence for disruption of ovarian function following adrenal release of follicular-phase progesterone. Results offer support for a potential mechanism by which fecundity could respond adaptively to the loss or lack of social support.

Maternal Distress and Offspring Neurodevelopment: Challenges and Opportunities for Pre-clinical Research Models

Pre-natal exposure to acute maternal trauma or chronic maternal distress can confer increased risk for psychiatric disorders in later life. Acute maternal trauma is the result of unforeseen environmental or personal catastrophes, while chronic maternal distress is associated with anxiety or depression. Animal studies investigating the effects of pre-natal stress have largely used brief stress exposures during pregnancy to identify critical periods of fetal vulnerability, a paradigm which holds face validity to acute maternal trauma in humans. While understanding these effects is undoubtably important, the literature suggests maternal stress in humans is typically chronic and persistent from pre-conception through gestation. In this review, we provide evidence to this effect and suggest a realignment of current animal models to recapitulate this chronicity. We also consider candidate mediators, moderators and mechanisms of maternal distress, and suggest a wider breadth of research is needed, along with the incorporation of advanced -omics technologies, in order to understand the neurodevelopmental etiology of psychiatric risk.

Progesterone - Friend or foe?

Estradiol is the "prototypic" sex hormone of women. Yet, women have another sex hormone, which is often disregarded: Progesterone. The goal of this article is to provide a comprehensive review on progesterone, and its metabolite allopregnanolone, emphasizing three key areas: biological properties, main functions, and effects on mood in women. Recent years of intensive research on progesterone and allopregnanolone have paved the way for new treatment of postpartum depression. However, treatment for premenstrual syndrome and premenstrual dysphoric disorder as well as contraception that women can use without risking mental health problems are still needed. As far as progesterone is concerned, we might be dealing with a two-edged sword: while its metabolite allopregnanolone has been proven useful for treatment of PPD, it may trigger negative symptoms in women with PMS and PMDD. Overall, our current knowledge on the beneficial and harmful effects of progesterone is limited and further research is imperative.

PPAR and functional foods: Rationale for natural neurosteroid-based interventions for postpartum depression

Allopregnanolone, a GABAergic neurosteroid and progesterone derivative, was recently approved by the Food and Drug Administration for the treatment of postpartum depression (PPD). Several mechanisms appear to be involved in the pathogenesis of PPD, including neuroendocrine dysfunction, neuroinflammation, neurotransmitter alterations, genetic and epigenetic modifications. Recent evidence highlights the higher risk for incidence of PPD in mothers exposed to unhealthy diets that negatively impact the microbiome composition and increase inflammation, all effects that are strongly correlated with mood disorders. Conversely, healthy diets have consistently been reported to decrease the risk of peripartum depression and to protect the body and brain against low-grade systemic chronic inflammation. Several bioactive micronutrients found in the so-called functional foods have been shown to play a relevant role in preventing neuroinflammation and depression, such as vitamins, minerals, omega-3 fatty acids and flavonoids. An intriguing molecular substrate linking functional foods with improvement of mood disorders may be represented by the peroxisome-proliferator activated receptor (PPAR) pathway, which can regulate allopregnanolone biosynthesis and brain-derived neurotropic factor (BDNF) and thereby may reduce inflammation and elevate mood. Herein, we discuss the potential connection between functional foods and PPAR and their role in preventing neuroinflammation and symptoms of PPD through neurosteroid regulation. We suggest that healthy diets by targeting the PPAR-neurosteroid axis and thereby decreasing inflammation may offer a suitable functional strategy to prevent and safely alleviate mood symptoms during the perinatal period.

Physiopathological role of the enzymatic complex 5α-reductase and 3α/β-hydroxysteroid oxidoreductase in the generation of progesterone and testosterone neuroactive metabolites

The enzymatic complex 5α-reductase (5α-R) and 3α/3β-hydroxysteroid oxidoreductase (HSOR) is expressed in the nervous system, where it transforms progesterone (PROG) and testosterone (T) into neuroactive metabolites. These metabolites regulate myelination, brain maturation, neurotransmission, reproductive behavior and the stress response. The expression of 5α-R and 3α-HSOR and the levels of PROG and T reduced metabolites show regional and sex differences in the nervous system and are affected by changing physiological conditions as well as by neurodegenerative and psychiatric disorders. A decrease in their nervous tissue levels may negatively impact the course and outcome of some pathological events. However, in other pathological conditions their increased levels may have a negative impact. Thus, the use of synthetic analogues of these steroids or 5α-R modulation have been proposed as therapeutic approaches for several nervous system pathologies. However, further research is needed to fully understand the consequences of these manipulations, in particular with 5α-R inhibitors.

The long-term but not short-term use of benzodiazepine impairs motoric function and upregulates amyloid β in part through the suppression of translocator protein

Many elderly American women use CNS depressant benzodiazepine (BZD) to ameliorate anxiety or insomnia. However, the chronic use of BZD (cBZD) is prevalent, causing adverse effects of BZD that include movement deficit. We previously reported that cBZD upregulates neurotoxic amyloid β42 (Aβ42) and downregulates neuroprotective translocator protein (TSPO) in the cerebellum, the brain area of movement and balance. The aim of the current study is two-fold: 1) to determine a direct effect of TSPO (inhibition) on cBZD-induced Aβ42 and Aβ-associated molecules; Aβ-producing-protein presenilin-1 (PS1) and Aβ-degrading-enzyme neprilysin and 2) to determine whether Aβ42 upregulation and motoric deficit occur upon a long-term (cBZD) rather than a short-term BZD (sBZD) treatment. Old female mice received BZD (lorazepam) for 20 days (cBZD) or 3 days (sBZD) with or without prototype TSPO ligand PK11195 and were tested for motoric performance for 3 days using Rotarod. ELISA was conducted to measure Aβ42 level and neprilysin activity in cerebellum. RT-PCR and immunoblot were conducted to measure the mRNA and protein levels of TSPO, PS1, and neprilysin. cBZD treatment decreased TSPO and neprilysin but increased Aβ42 accompanied by motoric deficit. Chronic PK11195 treatment acted as a TSPO inhibitor by suppressing TSPO expression and mimicked or exacerbated the effects of cBZD on all parameters measured except for PS1. None of the molecular and behavioral changes induced by cBZD were reproduced by sBZD treatment. These data suggest that cBZD upregulates Aβ42 and downregulates neprilysin in part through TSPO inhibition, the mechanisms distinct from sBZD, collectively contributing to motoric deficit.

An alternative theory for hormone effects on sex differences in PTSD: The role of heightened sex hormones during trauma

Women are at least twice as susceptible to developing post-traumatic stress disorder (PTSD) compared to men. Although most research seeking to explain this discrepancy has focussed on the role of oestradiol during fear extinction learning, the role of progesterone has been overlooked, despite relatively consistent findings being reported concerning the role of progesterone during consolidation of emotional and intrusive memories. In this review article, we outline literature supporting the role of progesterone on memory formation, with particular emphasis on potential memory-enhancing properties of progesterone when subjects are placed under stress. It is possible that progesterone directly and indirectly exerts memory-enhancing effects at the time of trauma, which is an effect that may not be necessarily captured during non-stressful paradigms. We propose a model whereby progesterone's steroidogenic relationship to cortisol and brain-derived neurotrophic factor in combination with elevated oestradiol may enhance emotional memory consolidation during trauma and therefore present a specific vulnerability to PTSD formation in women, particularly during the mid-luteal phase of the menstrual cycle.

Antidepressant-like effect of fluoxetine may depend on translocator protein activity and pretest session duration in forced swimming test in mice

The antidepressant-like effect of fluoxetine (20 mg/kg i.p.) has been assessed using the forced swimming test (FST) in IRC (CD-1) mice exposed or not to a pretest session of different duration (5 or 20 min). The influence of the mitochondrial translocator protein (TSPO) activity on the antidepressant-like effect of fluoxetine (20 mg/kg i.p.) in the FST was also studied. The antidepressant-like effect of fluoxetine was observed only in mice subjected to a 5-min pretest session 24 h before the FST. The TSPO antagonist PK11195 [1-(2-chlorophenyl)-N-methyl-N-(1-methylpropyl)-3-isoquinolinecarboxamide; 1 or 3 mg/kg i.p.] inhibited the antidepressant activity of fluoxetine in the FST. In the present study, fluoxetine or PK11195 was administered for a short duration. We suppose that the functional activity of TSPO may depend on a pretest session and that using this procedure is necessary to detect antidepressant activity of fluoxetine-like drugs.

Effectiveness of self-empowerment-affirmation-relaxation (Self-EAR) program for postpartum blues mothers: A randomize controlled trial

Background and Objecvites:

Approximately 55-85% of women worldwide have experienced postpartum blues (PPB) during 6-9 weeks after delivery without receiving the counseling program; more than 20% of them have developed into postpartum depression. Study objectives were to evaluate the effect of the Self-EAR program to improve the postpartum blues scores and serum allopregnanolone level among newly blues mothers.

Methods:

During June 2015 to May 2016, the randomized controlled trial was conducted among 76 Nulliparous blues mothers who were screened with Stein’s postpartum blues scores ≥ 3. All participants were randomly assigned either to the intervention group (Self-EAR program) and the control group (standard postpartum care program). The Self-EAR program was transformed into audio files which were installed in an MP3 digital device before providing it to the intervention group in order to be implemented at home three times per day for four weeks. Participants were assessed at baseline, 1-month, 2-month and 3-month follow-up for serum allopregnanolone level. Data were analyzed by using descriptive statistic, chi-square test, t-test, and repeated measure analysis of variance.

Result:

After the 3-month follow-up, the results revealed positive effects of the Self-EAR program on postpartum blues scores (p-value=0.002) and serum allopregnanolone concertation (p-value=0.001). The participants in the intervention group had experienced significantly lower postpartum blues scores; on the other hand, they had significantly higher serum allopregnanolone level when compared with the control group.

Conclusions:

The findings suggested that the Self-EAR program was effective to improve postpartum blues scores and allopregnanolone level among newly postpartum blues mothers.

Neurosteroids: non-genomic pathways in neuroplasticity and involvement in neurological diseases

Neurosteroids are neuroactive brain-born steroids. They can act through non-genomic and/or through genomic pathways. Genomic pathways are largely described for steroid hormones: the binding to nuclear receptors leads to transcription regulation. Pregnenolone, Dehydroepiandrosterone, their respective sulfate esters and Allopregnanolone have no corresponding nuclear receptor identified so far whereas some of their non-genomic targets have been identified. Neuroplasticity is the capacity that neuronal networks have to change their structure and function in response to biological and/or environmental signals; it is regulated by several mechanisms, including those that involve neurosteroids. In this review, after a description of their biosynthesis, the effects of Pregnenolone, Dehydroepiandrosterone, their respective sulfate esters and Allopregnanolone on their targets will be exposed. We then shall highlight that neurosteroids, by acting on these targets, can regulate neurogenesis, structural and functional plasticity. Finally, we will discuss the therapeutic potential of neurosteroids in the pathophysiology of neurological diseases in which alterations of neuroplasticity are associated with changes in neurosteroid levels.

FGIN-1-27, an agonist at translocator protein 18 kDa (TSPO), produces anti-anxiety and anti-panic effects in non-mammalian models

FGIN-1-27 is an agonist at the translocator protein 18 kDa (TSPO), a cholesterol transporter that is associated with neurosteroidogenesis. This protein has been identified as a peripheral binding site for benzodiazepines; in anamniotes, however, a second TSPO isoform that is absent in amniotes has been implicated in erythropoiesis. Functional conservation of the central benzodiazepine-binding site located in the GABA_A receptors has been demonstrated in anamniotes and amniotes alike; however, it was not previously demonstrated for TSPO. The present investigation explored the behavioral effects of FGIN-1-27 on an anxiety test in zebrafish (Danio rerio, Family: Cyprinide) and on a mixed anxiety/panic test on wall lizards (Tropidurus oreadicus, Family: Tropiduridae). Results showed that FGIN-1-27 reduced anxiety-like behavior in the zebrafish light/dark preference test similar to diazepam, but with fewer sedative effects. Similarly, FGIN-1-27 also reduced anxiety- and fear-like behaviors in the defense test battery in wall lizards, again producing fewer sedative-like effects than diazepam; the benzodiazepine was also unable to reduce fear-like behaviors in this species. These results A) underline the functional conservation of TSPO in defensive behavior in anamniotes; B) strengthen the proposal of using anamniote behavior as models in behavioral pharmacology; and C) suggest TSPO/neurosteroidogenesis as a target in treating anxiety disorders.

Progesterone for smoking relapse prevention following delivery: A pilot, randomized, double-blind study

INTRODUCTION

Close to half of women who were smokers prior to conception quit smoking in pregnancy, when endogenous progesterone levels are high. However, at least half resume pre-pregnancy smoking levels within weeks after delivery and when progesterone levels drop. The current pilot study tested the feasibility and preliminary efficacy of postpartum progesterone replacement in preventing relapse to smoking in postpartum women with a history of pre-pregnancy smoking.

METHODS

This was an 8-week, double-blind, parallel, randomized, placebo-controlled pilot trial of 41 women with a history of pre-pregnancy smoking who achieved abstinence by 32 weeks of gestation. Immediately following delivery women were randomized to oral micronized progesterone (200mg twice daily) or placebo via computerized urn randomization program. The main outcome measures were descriptions of study feasibility: recruitment and retention. Secondary outcomes were 7-day point prevalence of abstinence at week 8, time to relapse and smoking cravings.

RESULTS

The trial was feasible with adequate randomization, 64% (41/64) of eligible women, and trial retention, 78% (32/41) completed the trial. Women taking progesterone were 1.8 times more likely to be abstinent during week 8 and took longer to relapse (10 vs. 4 weeks) compared to the placebo group, although these differences did not reach statistical significance. After adjusting for age and pre-quit smoking level, the number needed to treat was 7. There was a 10% greater decline per week in craving ratings in the progesterone group compared to placebo (β=-0.10, 95% CI: -0.15, -0.04, p<0.01). No serious adverse events occurred during the trial.

CONCLUSIONS

These preliminary findings support the promise of progesterone treatment in postpartum smokers and could constitute a therapeutic breakthrough.If these preliminary findings can be evaluated and replicated in a larger study with sufficient power, this may constitute an acceptable and safe smoking relapse prevention strategy for use during lactation.

Calcium-engaged Mechanisms of Nongenomic Action of Neurosteroids

BACKGROUND

Neurosteroids form the unique group because of their dual mechanism of action. Classically, they bind to specific intracellular and/or nuclear receptors, and next modify genes transcription. Another mode of action is linked with the rapid effects induced at the plasma membrane level within seconds or milliseconds. The key molecules in neurotransmission are calcium ions, thereby we focus on the recent advances in understanding of complex signaling crosstalk between action of neurosteroids and calcium-engaged events.

METHODS

Short-time effects of neurosteroids action have been reviewed for GABAA receptor complex, glycine receptor, NMDA receptor, AMPA receptor, G protein-coupled receptors and sigma-1 receptor, as well as for several membrane ion channels and plasma membrane enzymes, based on available published research.

RESULTS

The physiological relevance of neurosteroids results from the fact that they can be synthesized and accumulated in the central nervous system, independently from peripheral sources. Fast action of neurosteroids is a prerequisite for genomic effects and these early events can significantly modify intracellular downstream signaling pathways. Since they may exert either positive or negative effects on calcium homeostasis, their role in monitoring of spatio-temporal Ca2+ dynamics, and subsequently, Ca2+-dependent physiological processes or initiation of pathological events, is evident.

CONCLUSION

Neurosteroids and calcium appear to be the integrated elements of signaling systems in neuronal cells under physiological and pathological conditions. A better understanding of cellular and molecular mechanisms of nongenomic, calcium-engaged neurosteroids action could open new ways for therapeutic interventions aimed to restore neuronal function in many neurological and psychiatric diseases.

Adapting to Stress: Understanding the Neurobiology of Resilience

There is significant variation in the way individuals react and respond to extreme stress and adversity. While some individuals develop psychiatric conditions such as posttraumatic stress disorder or major depressive disorder, others recover from stressful experiences without displaying significant symptoms of psychological ill-health, demonstrating stress-resilience. To understand why some individuals exhibit characteristics of a resilient profile, the interplay between neurochemical, genetic, and epigenetic processes over time needs to be explained. In this review, we examine the hormones, neuropeptides, neurotransmitters, and neural circuits associated with resilience and vulnerability to stress-related disorders. We debate how this increasing body of knowledge could also be useful in the creation of a stress-resilient profile. Additionally, identification of the underlying neurobiological components related to resilience may offer a contribution to improved approaches toward the prevention and treatment of stress-related disorders.

Lower allopregnanolone during pregnancy predicts postpartum depression: An exploratory study

Current evidence is mixed on the role of progesterone and its metabolites in perinatal mood and anxiety disorders. We measured second and third trimester (T2 and T3) progesterone (PROG) and allopregnanolone (ALLO) levels by ELISA and postpartum depression (PPD) by clinician interview (DSM-IV criteria) in 60 pregnant women with a prior diagnosis of a mood disorder. Methods included multivariate and logistic regression with general linear mixed effect models. We found that, after adjustment, every additional ng/mL of T2 ALLO resulted in a 63% (95% CI 13% to 84%, p=0.022) reduction in the risk of developing PPD. Our findings extend previous work connecting ALLO and depression within pregnancy, and indicate that the relationship between pregnancy ALLO and PPD is worth further exploration in a larger sample.

Hormonal systems, human social bonding, and affiliation

Which hormones are implicated in human social bonding and affiliation? And how does field research speak to this issue? We begin by laying out a broad view of how endocrine hormones in general modulate life history allocations of energy and other resources, and the ways in which their neuromodulatory functions must be understood within a broader conceptualization of how they have been shaped to affect allocations. We then turn to four specific hormones or hormone families that have received much attention: oxytocin, opioids, prolactin, and progesterone. Each plays a role in regulating psychological capacities and propensities that underlie individuals' interactions with important social targets. Yet in no case is it clear exactly what regulatory roles these hormones play. We suggest several directions for future research.

Maternal care and affective behavior in female offspring: Implication of the neurosteroid/GABAergic system

In female rats, the proestrus phase of the estrous cycle is associated with decreased levels of anxiety-like and depressive-like behavior relative to the metestrus phase. Progesterone likely modulate these behaviors, in part through the influence of its metabolite, allopregnanolone (THP) on hippocampal GABA_AR subunit expression. As natural variations in maternal care have been found to influence both progesterone levels at proestrus and anxiety-like behavior in female offspring, we sought to investigate the importance of maternal care and the estrous cycle on affective behavior in female rats that had received Low or High levels of licking/grooming (LG) during early life. Subjects were tested for anxiety-like behavior in the elevated plus maze at proestrus or metestrus or for estrous cycle-dependent changes in depressive-like anhedonic behavior with a saccharin preference test. GABA_AR subunit expression, and THP levels in the dorsal hippocampus and in plasma were also evaluated. Estrous cycle phase influenced saccharine preference and hippocampal THP level in both phenotypes. Low LG animals showed higher levels of hedonic behavior and anxiety-like behavior, irrespective of estrous cycle phase, as well as lower THP levels within the dorsal hippocampus when compared to High LG animals. Only High LG animals showed positive correlations between hippocampal THP levels and GABA_AR subunit expression, suggesting a relative insensitivity to THP's modulation of these receptor subunits in Low LG offspring. These findings suggest that natural variations in maternal care influence anxiety-like and hedonic behavior through the modulation of the neurosteroid/GABAergic system.

Why are women so vulnerable to anxiety, trauma-related and stress-related disorders? The potential role of sex hormones

Increased prevalence, severity, and burden of anxiety, trauma-related and stress-related disorders in women compared with men has been well documented. Evidence from a variety of fields has emerged suggesting that sex hormones, particularly oestradiol and progesterone, play a significant part in generation of these sex differences. In this Series paper, we aim to integrate the literature reporting on the effects of sex hormones on biological, behavioural, and cognitive pathways, to propose two broad mechanisms by which oestradiol and progesterone influence sex differences in anxiety disorders: augmentation of vulnerability factors associated with anxiety disorder development; and facilitation of the maintenance of anxious symptoms post-development. The implications for future research, along with novel approaches to psychological and pharmacological treatment of anxiety disorders, are also considered.

Increased Motor-Impairing Effects of the Neuroactive Steroid Pregnanolone in Mice with Targeted Inactivation of the GABAA Receptor γ2 Subunit in the Cerebellum

Endogenous neurosteroids and neuroactive steroids have potent and widespread actions on the brain via inhibitory GABA_A receptors. In recombinant receptors and genetic mouse models their actions depend on the α, β, and δ subunits of the receptor, especially on those that form extrasynaptic GABA_A receptors responsible for non-synaptic (tonic) inhibition, but they also act on synaptically enriched γ2 subunit-containing receptors and even on αβ binary receptors. Here we tested whether behavioral sensitivity to the neuroactive steroid agonist 5β-pregnan-3α-ol-20-one is altered in genetically engineered mouse models that have deficient GABA_A receptor-mediated synaptic inhibition in selected neuronal populations. Mouse lines with the GABA_A receptor γ2 subunit gene selectively deleted either in parvalbumin-containing cells (including cerebellar Purkinje cells), cerebellar granule cells, or just in cerebellar Purkinje cells were trained on the accelerated rotating rod and then tested for motor impairment after cumulative intraperitoneal dosing of 5β-pregnan-3α-ol-20-one. Motor-impairing effects of 5β-pregnan-3α-ol-20-one were strongly increased in all three mouse models in which γ2 subunit-dependent synaptic GABA_A responses in cerebellar neurons were genetically abolished. Furthermore, rescue of postsynaptic GABA_A receptors in Purkinje cells normalized the effect of the steroid. Anxiolytic/explorative effects of the steroid in elevated plus maze and light:dark exploration tests in mice with Purkinje cell γ2 subunit inactivation were similar to those in control mice. The results suggest that, when the deletion of γ2 subunit has removed synaptic GABA_A receptors from the specific cerebellar neuronal populations, the effects of neuroactive steroids solely on extrasynaptic αβ or αβδ receptors lead to enhanced changes in the cerebellum-generated behavior.

Oxytocin receptor DNA methylation in postpartum depression

The oxytocin receptor (OXTR) is a key regulator of stress and anxiety and may be regulated by both psychosocial risk factors and gonadal hormones, making it an attractive candidate for study in postpartum depression (PPD). The objective of this study was to investigate both serum hormone and PPD specific DNA methylation variation in the OXTR. Illumina HM450 microarray data generated in a prospective PPD cohort identified significant associations (P=0.014) with PPD in an intronic region in the OXTR located 4bp proximal to an estrogen receptor (ER) binding region. Pyrosequencing confirmed moderate evidence for an interaction of CpGs in the region with childhood abuse status to mediate PPD. These CpGs located on chr3 at positions 8810078 and 8810069 exhibited significant associations with postpartum depression scores from an independent cohort of 240 women with no prior psychiatric history. Hormone analysis suggested a PPD specific negative correlation of DNA methylation in the region with serum estradiol levels. Estradiol levels and OXTR DNA methylation exhibited a significant interaction to associate with the ratio of allopregnanolone to progesterone. Cumulatively, the data corroborate our previous hypotheses of a PPD specific increased sensitivity of epigenetic reprogramming at estrogen target genes and suggests that OXTR epigenetic variation may be an important mediator of mood relevant neuroactive steroid production.

Replication of Epigenetic Postpartum Depression Biomarkers and Variation with Hormone Levels

DNA methylation variation at HP1BP3 and TTC9B is modified by estrogen exposure in the rodent hippocampus and was previously shown to be prospectively predictive of postpartum depression (PPD) when modeled in antenatal blood. The objective of this study was to replicate the predictive efficacy of the previously established model in women with and without a previous psychiatric diagnosis and to understand the effects of changing hormone levels on PPD biomarker loci. Using a statistical model trained on DNA methylation data from N=51 high-risk women, we prospectively predicted PPD status in an independent N=51 women using first trimester antenatal gene expression levels of HP1BP3 and TTC9B, with an area under the receiver operator characteristic curve (AUC) of 0.81 (95% CI: 0.69-0.92, p<5 × 10(-4)). Modeling DNA methylation of these genes in N=240 women without a previous psychiatric diagnosis resulted in a cross-sectional prediction of PPD status with an AUC of 0.81 (95% CI: 0.68-0.93, p=0.01). TTC9B and HP1BP3 DNA methylation at early antenatal time points showed moderate evidence for association to the change in estradiol and allopregnanolone over the course of pregnancy, suggesting that epigenetic variation at these loci may be important for mediating hormonal sensitivity. In addition both loci showed PPD-specific trajectories with age, possibly mediated by age-associated hormonal changes. The data add to the growing body of evidence suggesting that PPD is mediated by differential gene expression and epigenetic sensitivity to pregnancy hormones and that modeling proxies of this sensitivity enable accurate prediction of PPD.

Steroids and endocrine disruptors--History, recent state of art and open questions

This introductory chapter provides an overview of the levels and sites at which endocrine disruptors (EDs) affect steroid actions. In contrast to the special issue of Journal of Steroid Biochemistry and Molecular Biology published three years ago and devoted to EDs as such, this paper focuses on steroids. We tried to point to more recent findings and opened questions. EDs interfere with steroid biosynthesis and metabolism either as inhibitors of relevant enzymes, or at the level of their expression. Particular attention was paid to enzymes metabolizing steroid hormones to biologically active products in target cells, such as aromatase, 5α-reductase and 3β-, 11β- and 17β-hydroxysteroid dehydrogenases. An important target for EDs is also steroid acute regulatory protein (StAR), responsible for steroid precursor trafficking to mitochondria. EDs influence receptor-mediated steroid actions at both genomic and non-genomic levels. The remarkable differences in response to various steroid-receptor ligands led to a more detailed investigation of events following steroid/disruptor binding to the receptors and to the mapping of the signaling cascades and nuclear factors involved. A virtual screening of a large array of EDs with steroid receptors, known as in silico methods (≡computer simulation), is another promising approach for studying quantitative structure activity relationships and docking. New data may be expected on the effect of EDs on steroid hormone binding to selective plasma transport proteins, namely transcortin and sex hormone-binding globulin. Little information is available so far on the effects of EDs on the major hypothalamo-pituitary-adrenal/gonadal axes, of which the kisspeptin/GPR54 system is of particular importance. Kisspeptins act as stimulators for hormone-induced gonadotropin secretion and their expression is regulated by sex steroids via a feed-back mechanism. Kisspeptin is now believed to be one of the key factors triggering puberty in mammals, and various EDs affect its expression and function. Finally, advances in analytics of EDs, especially those persisting in the environment, in various body fluids (plasma, urine, seminal fluid, and follicular fluid) are mentioned. Surprisingly, relatively scarce information is available on the simultaneous determination of EDs and steroids in the same biological material. This article is part of a Special Issue entitled 'Endocrine disruptors & steroids'.

Adverse effects of 5α-reductase inhibitors: What do we know, don't know, and need to know?

Steroids are important physiological orchestrators of endocrine as well as peripheral and central nervous system functions. One of the key processes for regulation of these molecules lies in their enzymatic processing by a family of 5α-reductase (5α-Rs) isozymes. By catalyzing a key rate-limiting step in steroidogenesis, this family of enzymes exerts a crucial role not only in the physiological control but also in pathological events. Indeed, both 5α-R inhibition and supplementation of 5α-reduced metabolites are currently used or have been proposed as therapeutic strategies for a wide array of pathological conditions. In particular, the potent 5α-R inhibitors finasteride and dutasteride are used in the treatments of benign prostatic hyperplasia (BPH), as well as in male pattern hair loss (MPHL) known as androgenetic alopecia (AGA). Recent preclinical and clinical findings indicate that 5α-R inhibitors evoke not only beneficial, but also adverse effects. Future studies should investigate the biochemical and physiological mechanisms that underlie the persistence of the adverse sexual side effects to determine why a subset of patients is afflicted with such persistence or irreversible adverse effects. Also a better focus of clinical research is urgently needed to better define those subjects who are likely to be adversely affected by such agents. Furthermore, research on the non-sexual adverse effects such as diabetes, psychosis, depression, and cognitive function are needed to better understand the broad spectrum of the effects these drugs may elicit during their use in treatment of AGA or BPH. In this review, we will summarize the state of art on this topic, overview the key unresolved questions that have emerged on the pharmacological targeting of these enzymes and their products, and highlight the need for further studies to ascertain the severity and duration of the adverse effects of 5α-R inhibitors, as well as their biological underpinnings.

Loneliness: clinical import and interventions

In 1978, when the Task Panel report to the US President's Commission on Mental Health emphasized the importance of improving health care and easing the pain of those suffering from emotional distress syndromes including loneliness, few anticipated that this issue would still need to be addressed 40 years later. A meta-analysis (Masi et al., 2011) on the efficacy of treatments to reduce loneliness identified a need for well-controlled randomized clinical trials focusing on the rehabilitation of maladaptive social cognition. We review assessments of loneliness and build on this meta-analysis to discuss the efficacy of various treatments for loneliness. With the advances made over the past 5 years in the identification of the psychobiological and pharmaceutical mechanisms associated with loneliness and maladaptive social cognition, there is increasing evidence for the potential efficacy of integrated interventions that combine (social) cognitive behavioral therapy with short-term adjunctive pharmacological treatments.

Stress and opioids: role of opioids in modulating stress-related behavior and effect of stress on morphine conditioned place preference

Research studies have defined the important role of endogenous opioids in modulating stress-associated behavior. The release of β-endorphins in the amygdala in response to stress helps to cope with a stressor by inhibiting the over-activation of HPA axis. Administration of mu opioid agonists reduces the risk of developing post-traumatic stress disorder (PTSD) following a traumatic event by inhibiting fear-related memory consolidation. Similarly, the release of endogenous enkephalin and nociceptin in the basolateral amygdala and the nucleus accumbens tends to produce the anti-stress effects. An increase in dynorphin levels during prolonged exposure to stress may produce learned helplessness, dysphoria and depression. Stress also influences morphine-induced conditioned place preference (CPP) depending upon the intensity and duration of the stressor. Acute stress inhibits morphine CPP, while chronic stress potentiates CPP. The development of dysphoria due to increased dynorphin levels may contribute to chronic stress-induced potentiation of morphine CPP. The activation of ERK/cyclic AMP responsive element-binding (CREB) signaling in the mesocorticolimbic area, glucocorticoid receptors in the basolateral amygdala, and norepinephrine and galanin system in the nucleus accumbens may decrease the acute stress-induced inhibition of morphine CPP. The increase in dopamine levels in the nucleus accumbens and augmentation of GABAergic transmission in the median prefrontal cortex may contribute in potentiating morphine CPP. Stress exposure reinstates the extinct morphine CPP by activating the orexin receptors in the nucleus accumbens, decreasing the oxytocin levels in the lateral septum and amygdala, and altering the GABAergic transmission (activation of GABAA and inactivation of GABAB receptors). The present review describes these varied interactions between opioids and stress along with the possible mechanism.