The role of allopregnanolone in depression and anxiety

Changes in neuroactive steroids, neurotrophins and immunological biomarkers after monotherapy 8-week rTMS treatment and their relationship with neurocognitive functions in depression

Repetitive transcranial magnetic stimulation (rTMS) has proven effective in the treatment of major depression. The underlying mechanisms of action are still poorly understood. We aimed to evaluate the changes in the levels of neuroactive steroids, neurotrophins and immunological biomarkers before and after rTMS treatment and assess the relationship of this change between clinical response and cognitive functions after monotherapy rTMS treatment. Twenty-three patients with major depressive disorder (MDD) and 25 matched healthy controls were included in the study. The Hamilton Depression Rating Scale (HDRS), Trail Making Test A and B forms and Digit Span Test were administered. Biomarkers (BDNF, TNF-α, IL-1ß, NAS) were run in the peripheral blood at the end of the first month that rTMS was administered daily and at the end of the 2nd month when that rTMS was administered once a week. Appropriate conditions were provided so that the relevant biomarkers were not affected by the biorhythm. After rTMS monotherapy, an increase in BDNF and allopregnanolone, a decrease in TNF-α, IL-1ß, DHEA, and DHEA-S levels was found to be statistically significant. The scores on cognitive tests increased with the treatment. Positive significant correlations was found between BDNF levels and cognitive tests at the end of the first and second months. Our findings suggest that the effects of rTMS treatment may be related to the neuroendocrine, neurotrophin, and immunological mechanisms. rTMS treatment is found to have positive effects on cognitive functions in the short term.

5β-reduced neuroactive steroids as modulators of growth and viability of postnatal neurons and glia

Endogenous neurosteroids (NS) and their synthetic analogs, neuroactive steroids (NAS), are potentially useful drug-like compounds affecting the pathophysiology of miscellaneous central nervous system disorders (e.g. Alzheimer´s disease, epilepsy, depression, etc.). Additionally, NS have been shown to promote neuron viability and neurite outgrowth upon injury. The molecular, structural and physicochemical basis of the NS effect on neurons is so far not fully understood, and the development of new, biologically relevant assays is essential for their comparative analysis and for assessment of their mechanism of action. Here, we report the development of a novel, plate-based, high-content in vitro assay for screening of NS and newly synthesized, 5β-reduced NAS for the promotion of postnatal neuron survival and neurite growth using fluorescent, postnatal mixed cortical neuron cultures isolated from thy1-YFP transgenic mice. The screen allows a detailed time course analysis of different parameters, such as the number of neurons or neurite lengths of 7-day, in vitro neuron cultures. Using the screen, we identify a new NAS, compound 42, that promotes the survival and growth of postnatal neurons significantly better than several endogenous NS (dehydroepiandrosterone, progesterone, and allopregnanolone). Interestingly, we demonstrate that compound 42 also promotes the proliferation of glia (in particular oligodendrocytes) and that the glial function is critical for its neuron growth support. Computational analysis of the biological data and calculated physicochemical properties of tested NS and NAS demonstrated that their biological activity is proportional to their lipophilicity. Together, the screen proves useful for the selection of neuron-active NAS and the comparative evaluation of their biologically relevant structural and physicochemical features.

Neurosteroids: A potential target for neuropsychiatric disorders

Neurosteroids are steroids produced by endocrine glands and subsequently entering the brain, and also include steroids synthesis in the brain. It has been widely known that neurosteroids influence many neurological functions, including neuronal signaling, synaptic adaptations, and neuroprotective effects. In addition, abnormality in the synthesis and function of neurosteroids has been closely linked to neuropsychiatric disorders, such as Alzheimer's disease (AD), schizophrenia (SZ), and epilepsy. Given their important role in brain pathophysiology and disorders, neurosteroids offer potential therapeutic targets for a variety of neuropsychiatric diseases, and that therapeutic strategies targeting neurosteroids probably exert beneficial effects. We therefore summarized the role of neurosteroids in brain physiology and neuropsychiatric disorders, and introduced the recent findings of synthetic neurosteroid analogues for potential treatment of neuropsychiatric disorders, thereby providing insights for further research in the future.

Neuroactive Steroids, Toll-like Receptors, and Neuroimmune Regulation: Insights into Their Impact on Neuropsychiatric Disorders

Pregnane neuroactive steroids, notably allopregnanolone and pregnenolone, exhibit efficacy in mitigating inflammatory signals triggered by toll-like receptor (TLR) activation, thus attenuating the production of inflammatory factors. Clinical studies highlight their therapeutic potential, particularly in conditions like postpartum depression (PPD), where the FDA-approved compound brexanolone, an intravenous formulation of allopregnanolone, effectively suppresses TLR-mediated inflammatory pathways, predicting symptom improvement. Additionally, pregnane neurosteroids exhibit trophic and anti-inflammatory properties, stimulating the production of vital trophic proteins and anti-inflammatory factors. Androstane neuroactive steroids, including estrogens and androgens, along with dehydroepiandrosterone (DHEA), display diverse effects on TLR expression and activation. Notably, androstenediol (ADIOL), an androstane neurosteroid, emerges as a potent anti-inflammatory agent, promising for therapeutic interventions. The dysregulation of immune responses via TLR signaling alongside reduced levels of endogenous neurosteroids significantly contributes to symptom severity across various neuropsychiatric disorders. Neuroactive steroids, such as allopregnanolone, demonstrate efficacy in alleviating symptoms of various neuropsychiatric disorders and modulating neuroimmune responses, offering potential intervention avenues. This review emphasizes the significant therapeutic potential of neuroactive steroids in modulating TLR signaling pathways, particularly in addressing inflammatory processes associated with neuropsychiatric disorders. It advances our understanding of the complex interplay between neuroactive steroids and immune responses, paving the way for personalized treatment strategies tailored to individual needs and providing insights for future research aimed at unraveling the intricacies of neuropsychiatric disorders.

Effect of nutritional interventions on the psychological symptoms of premenstrual syndrome in women of reproductive age: a systematic review of randomized controlled trials

CONTEXT

Premenstrual syndrome (PMS) affects approximately 48% of women of reproductive age worldwide. It can lead to functional impairment, lower quality of life, and decreased work productivity. Despite the availability of medical treatment options, women are seeking alternative interventions because of concerns of harmful side effects and limited evidence of efficacy associated with pharmacological treatments. To date, high-quality research investigating the effects of dietary and nutrient intervention on PMS is limited.

OBJECTIVE

This systematic review investigated the effect of nutritional interventions on the psychological symptoms of PMS.

DATA SOURCES

Five electronic databases were searched for randomized controlled trials (RCTs) published in English from inception to October 2022. Trials eligible for inclusion were nutritional intervention studies involving women of reproductive age that measured PMS-associated psychological outcomes.

DATA EXTRACTION

Articles were selected using prespecified inclusion criteria. Data screening and extraction and risk-of-bias assessments were conducted by 3 independent reviewers using article screening software and the Cochrane Risk of Bias 2 tool.

DATA ANALYSIS

Thirty-two articles reporting on 31 RCTs involving 3254 participants, ranging in age from 15 to 50 years were included and narratively reviewed. Only 1 of the included studies had a low risk of bias. Treatment with vitamin B6, calcium, and zinc consistently had significant positive effects on the psychological symptoms of PMS. There was insufficient evidence to support the effects of vitamin B1, vitamin D, whole-grain carbohydrates, soy isoflavones, dietary fatty acids, magnesium, multivitamin supplementation, or PMS-specific diets.

CONCLUSIONS

There is some evidence to support the use of nutritional interventions for improving psychological symptoms of PMS. However, more research using consistent protocols, procedures to minimize risk of bias, intention-to-treat analysis, and clearer reporting is required to provide conclusive nutritional recommendations for improving PMS-related psychological outcomes.

PROSPERO REGISTRATION NO

CRD42022369999.

Microbial and metabolomic profiles of type 1 diabetes with depression: A case-control study

BACKGROUND

Depression is the most common psychological disorder in patients with type 1 diabetes (T1D). However, the characteristics of microbiota and metabolites in these patients remain unclear. This study aimed to investigate microbial and metabolomic profiles and identify novel biomarkers for T1D with depression.

METHODS

A case-control study was conducted in a total of 37 T1D patients with depression (TD+), 35 T1D patients without depression (TD-), and 29 healthy controls (HCs). 16S rRNA gene sequencing and liquid chromatography-mass spectrometry (LC-MS) metabolomics analysis were conducted to investigate the characteristics of microbiota and metabolites. The association between altered microbiota and metabolites was explored by Spearman's rank correlation and visualized by a heatmap. The microbial signatures to discriminate TD+ from TD- were identified by a random forest (RF) classifying model.

RESULTS

In microbiota, 15 genera enriched in TD- and 2 genera enriched in TD+, and in metabolites, 14 differential metabolites (11 upregulated and 3 downregulated) in TD+ versus TD- were identified. Additionally, 5 genera (including Phascolarctobacterium, Butyricimonas, and Alistipes from altered microbiota) demonstrated good diagnostic power (area under the curve [AUC] = 0.73; 95% CI, 0.58-0.87). In the correlation analysis, Butyricimonas was negatively correlated with glutaric acid (r = -0.28, p = 0.015) and malondialdehyde (r = -0.30, p = 0.012). Both Phascolarctobacterium (r = 0.27, p = 0.022) and Alistipes (r = 0.31, p = 0.009) were positively correlated with allopregnanolone.

CONCLUSIONS

T1D patients with depression were characterized by unique profiles of gut microbiota and serum metabolites. Phascolarctobacterium, Butyricimonas, and Alistipes could predict the risk of T1D with depression. These findings provide further evidence that the microbiota-gut-brain axis is involved in T1D with depression.

The role of neurosteroids in posttraumatic stress disorder and alcohol use disorder: A review of 10 years of clinical literature and treatment implications

Rates of alcohol use disorder (AUD) are increasing in men and women and there are high rates of concurrent posttraumatic stress disorder (PTSD) and AUD. AUD and PTSD synergistically increase symptomatology and negatively affect treatment outcomes; however, there are very limited pharmacological treatments for PTSD/AUD. Neurosteroids have been implicated in the underlying neurobiological mechanisms of both PTSD and AUD and may be a target for treatment development. This review details the past ten years of research on pregnenolone, progesterone, allopregnanolone, pregnanolone, estradiol, testosterone and dehydroepiandrosterone/dehydroepiandrosterone-sulfate (DHEA/DHEA-S) in the context of PTSD and AUD, including examination of trauma/alcohol-related variables, such as stress-reactivity. Emerging evidence that exogenous pregnenolone, progesterone, and allopregnanolone may be promising, novel interventions is also discussed. Specific emphasis is placed on examining the application of sex as a biological variable in this body of literature, given that women are more susceptible to both PTSD diagnoses and stress-related alcohol consumption.

Prelimbic and infralimbic responsivity to amygdala input is modified by gonadal hormones in parallel to low anxiety-like behavior in ovariectomized rats

Gonadal hormones may influence sexual activity by reducing anxiety. The basolateral amygdala (BLA) and prelimbic (PL) and infralimbic (IL) cortical regions comprise a loop that is related to fear, anxiety, and social behavior. In female ovariectomized rats, actions of estradiol, progesterone, and sequential estradiol and progesterone administration were explored in the open field test (OFT) and plus maze test (PMT) to evaluate signs of anxiety-like behavior. The three hormonal treatments reduced indicators of anxiety in the PMT but did not influence behavior in the OFT. In the same behaviorally tested rats under urethane anesthesia, single-unit extracellular recordings were obtained from the PL and IL during electrical stimulation of the BLA. The analysis of 250 ms peristimulus histograms showed that BLA stimulation produced two kinds of response. A small group of neurons increased their firing rate after BLA stimulation. Most neurons exhibited a reduction of spiking. Neurons that increased their firing rate after BLA stimulation did not show any difference with the hormonal treatments. In neurons that were inhibited by BLA stimulation, estradiol reduced the neuronal firing rate in the PL and IL, and progesterone alone and the sequential administration of estradiol followed by progesterone administration 24 h later (priming) increased the firing rate during the 240 ms before BLA stimulation. Analyses of responsivity of the PL and IL during electrical stimulation of the BLA indicated that estradiol, progesterone, and estradiol followed by progesterone administration 24 h later (priming) reduced inhibitory actions of the BLA on the PL but not IL. In the BLA-IL connection, progesterone exacerbated the inhibitory response. These findings indicate that anxiolytic actions of estradiol, progesterone, and estradiol followed by progesterone administration 24 h later (priming) correspond to lower BLA-PL responsivity. Actions of progesterone on BLA-IL responsivity appear to contribute to sexual activity by interacting with other forebrain structures that are also related to sexual receptivity.

Evaluation of Midazolam-Ketamine-Allopregnanolone Combination Therapy against Cholinergic-Induced Status Epilepticus in Rats

Status epilepticus (SE) is a life-threatening development of self-sustaining seizures that becomes resistant to benzodiazepines when treatment is delayed. Benzodiazepine pharmacoresistance is thought in part to result from internalization of synaptic GABAA receptors, which are the main target of the drug. The naturally occurring neurosteroid allopregnanolone is a therapy of interest against SE for its ability to modulate all isoforms of GABAA receptors. Ketamine, an N-methyl-D-aspartate (NMDA) receptor antagonist, has been partially effective in combination with benzodiazepines in mitigating SE-associated neurotoxicity. In this study, allopregnanolone as an adjunct to midazolam or midazolam-ketamine combination therapy was evaluated for efficacy against cholinergic-induced SE. Adult male rats implanted with electroencephalographic (EEG) telemetry devices were exposed to the organophosphorus chemical (OP) soman (GD) and treated with an admix of atropine sulfate and HI-6 at 1 minute after exposure followed by midazolam, midazolam-allopregnanolone, or midazolam-ketamine-allopregnanolone 40 minutes after seizure onset. Neurodegeneration, neuronal loss, and neuroinflammation were assessed 2 weeks after GD exposure. Seizure activity, EEG power integral, and epileptogenesis were also compared among groups. Overall, midazolam-ketamine-allopregnanolone combination therapy was effective in reducing cholinergic-induced toxic signs and neuropathology, particularly in the thalamus and hippocampus. Higher dosage of allopregnanolone administered in combination with midazolam and ketamine was also effective in reducing EEG power integral and epileptogenesis. The current study reports that there is a promising potential of neurosteroids in combination with benzodiazepine and ketamine treatments in a GD model of SE. SIGNIFICANCE STATEMENT: Allopregnanolone, a naturally occurring neurosteroid, reduced pathologies associated with soman (GD) exposure such as epileptogenesis, neurodegeneration, and neuroinflammation, and suppressed GD-induced toxic signs when used as an adjunct to midazolam and ketamine in a delayed treatment model of soman-induced status epilepticus (SE) in rats. However, protection was incomplete, suggesting that further studies are needed to identify optimal combinations of antiseizure medications and routes of administration for maximal efficacy against cholinergic-induced SE.

Neurosteroids: mechanistic considerations and clinical prospects

Like other classes of treatments described in this issue's section, neuroactive steroids have been studied for decades but have risen as a new class of rapid-acting, durable antidepressants with a distinct mechanism of action from previous antidepressant treatments and from other compounds covered in this issue. Neuroactive steroids are natural derivatives of progesterone but are proving effective as exogenous treatments. The best understood mechanism is that of positive allosteric modulation of GABAA receptors, where subunit selectivity may promote their profile of action. Mechanistically, there is some reason to think that neuroactive steroids may separate themselves from liabilities of other GABA modulators, although research is ongoing. It is also possible that intracellular targets, including inflammatory pathways, may be relevant to beneficial actions. Strengths and opportunities for further development include exploiting non-GABAergic targets, structural analogs, enzymatic production of natural steroids, precursor loading, and novel formulations. The molecular mechanisms of behavioral effects are not fully understood, but study of brain network states involved in emotional processing demonstrate a robust influence on affective states not evident with at least some other GABAergic drugs including benzodiazepines. Ongoing studies with neuroactive steroids will further elucidate the brain and behavioral effects of these compounds as well as likely underpinnings of disease.

Post-Finasteride Syndrome And Post-Ssri Sexual Dysfunction: Two Clinical Conditions Apparently Distant, But Very Close

Post-finasteride syndrome and post-SSRI sexual dysfunction, are two poorly explored clinical conditions in which men treated for androgenetic alopecia with finasteride or for depression with SSRI antidepressants show persistent side effects despite drug suspension (e.g., sexual dysfunction, psychological complaints, sleep disorders). Because of some similarities in the symptoms, common pathological mechanisms are proposed here. Indeed, as discussed, clinical studies and preclinical data obtained so far suggest an important role for brain modulators (i.e., neuroactive steroids), neurotransmitters (i.e., serotonin, and cathecolamines), and gut microbiota in the context of the gut-brain axis. In particular, the observed interconnections of these signals in these two clinical conditions may suggest similar etiopathogenetic mechanisms, such as the involvement of the enzyme converting norepinephrine into epinephrine (i.e., phenylethanolamine N-methyltransferase). However, despite the current efforts, more work is still needed to advance the understanding of these clinical conditions in terms of diagnostic markers and therapeutic strategies.

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.

Research Trends and Hot Spots of Allopregnanolone Research in the Last 20 Years: A Bibliometric Analysis

Background

Allopregnanolone is a kind of neuroactive steroid or neurosteroid in the central nervous system that acts as an endogenenous GABAA receptor positive modulator. However, at present, no comprehensive bibliometric analysis regarding allopregnanolone research is available. In our study, we intend to analyze the research trends and hot spots related to allopregnanolone in the past 20 years.

Methods

We searched for allopregnanolone related articles and reviews between 2004 and 2023 from the Web of Science Core Collection database. Then, the bibliometric analysis was conducted using VOSviewer, CiteSpace, Microsoft Excel 2019, as well as the online bibliometric analysis platform (http://bibliometric.com/).

Results

A total of 1841 eligible publications were identified. The number of annual publications and citations was generally on the rise. Among countries, the United States ranked first in overall publications, citations, international cooperation, and the number of research institutions. The University of North Carolina was the most active institution, conducting numerous preclinical and clinical work that focusing on allopregnanolone treatment for diverse psychiatric or neurologic disorders. As for authors, Dr. Frye CA, Morrow AL, and Pinna G were identified as the top three prolific scholars due to their great publications and citations. Based on the publication clusters and citation bursts analysis, the keyword co-occurrence network, the strongest citation bursts, and co-cited references analysis, the hot spots in recent years included "depression", "postpartum depression", "GABAA receptor", and so on.

Conclusion

Allopregnanolone is still a popular area of research, and the United States leads the way in this area. Dr. Frye CA, Morrow AL, Pinna G, and their teams contributed greatly to the mechanism study and translation study of allopregnanolone. The use of allopregnanolone for the treatment of psychiatric or neurologic disorders, especially postpartum depression, is the current hot spot. However, the underlying mechanisms of anti-depression are still not clear, deserving more in-depth research.

Testosterone and Prolactin Perturbations Possibly Associated with Reduced Levels of β-Arrestin1 in Mononuclear Leukocytes of Women with Premenstrual Dysphoric Disorder

Previously, we reported that a reduction in β-Arrestin1 protein levels in peripheral blood mononuclear leukocytes (PBMC) significantly correlated with the severity of depression symptoms in women with premenstrual dysphoric disorder (PMDD). This study aimed to determine whether the reduced premenstrual β-Arrestin1 protein levels were associated with changes in the regulator for late luteal phase progesterone secretion. The study participants (n = 25) were non-pregnant women between 18 and 42 years of age not taking any antidepressants or receiving therapy and experiencing the luteal phase of menstruation. ELISA determined the β-Arrestin1 protein in PBMC; testosterone and prolactin levels from the plasma were determined by radioimmunoassay. Reduced levels of β-Arrestin1 protein in women with Hamilton Rating Scale for Depression (HAM-D) scores above 19 were observed alongside significantly higher plasma testosterone and prolactin concentrations. Understanding the mechanism underlying the initiation of PMDD will allow for identification of a key perturbed metabolic enzyme that can serve as a target for drug development to ensure the alleviation of PMDD, which has been suggested earlier as a risk factor for developing major depressive disorders.

Neurosteroids and translocator protein 18 kDa (TSPO) in depression: implications for synaptic plasticity, cognition, and treatment options

There is need for novel fast acting treatment options in affective disorders. 3α-reduced neurosteroids such as allopregnanolone are powerful positive allosteric modulators of GABAA receptors and target also extrasynaptic receptors. Their synthesis is mediated by the translocator protein 18 kDa (TSPO). TSPO ligands not only promote endogenous neurosteroidogenesis, but also exert a broad spectrum of functions involving modulation of mitochondrial activity and acting as anti-inflammatory and neuroregenerative agents. Besides affective symptoms, in depression cognitive impairment can be frequently observed, which may be ameliorated through targeting of extrasynaptic GABAA receptors either via TSPO ligands or exogenously administered 3α-reduced neurosteroids. Interestingly, recent findings indicate an enhanced activation of the complement system, e.g., enhanced expression of C1q, both in depression and dementia. It is of note that benzodiazepines have been shown to reduce long-term potentiation and to cause cognitive decline. Intriguingly, TSPO may be crucial in mediating the effects of benzodiazepines on synaptic pruning. Here, we discuss how benzodiazepines and TSPO may interfere with synaptic pruning. Moreover, we highlight recent developments of TSPO ligands and 3α-reduced neurosteroids as therapeutic agents. Etifoxine is the only clinically available TSPO ligand so far and has been studied in anxiety disorders. Regarding 3α-reduced neurosteroids, brexanolone, an intravenous formulation of allopregnanolone, has been approved for the treatment of postpartum depression and zuranolone, an orally available 3α-reduced neurosteroid, is currently being studied in major depressive disorder and postpartum depression. As such, 3α-reduced neurosteroids and TSPO ligands may constitute promising treatment approaches for affective disorders.

GABAA receptors as targets for treating affective and cognitive symptoms of depression

In the past 20 years, our understanding of the pathophysiology of depression has evolved from a focus on an imbalance of monoaminergic neurotransmitters to a multifactorial picture including an improved understanding of the role of glutamatergic excitatory and GABAergic inhibitory neurotransmission. FDA-approved treatments targeting the glutamatergic [esketamine for major depressive disorder (MDD)] and GABAergic (brexanolone for peripartum depression) systems have become available. This review focuses on the GABAA receptor (GABAAR) system as a target for novel antidepressants and discusses the mechanisms by which modulation of δ-containing GABAARs with neuroactive steroids (NASs) or of α5-containing GABAARs results in antidepressant or antidepressant-like actions and discusses clinical data on NASs. Moreover, a potential mechanism by which α5-GABAAR-positive allosteric modulators (PAMs) may improve cognitive deficits in depression is presented.

GABA-ergic Modulators: New Therapeutic Approaches to Premenstrual Dysphoric Disorder

Premenstrual dysphoric disorder (PMDD) is characterized by the predictable onset of mood and physical symptoms secondary to gonadal steroid fluctuation during the luteal phase of the menstrual cycle. Although menstrual-related affective dysfunction is responsible for considerable functional impairment and reduction in quality of life worldwide, currently approved treatments for PMDD are suboptimal in their effectiveness. Research over the past two decades has suggested that the interaction between allopregnanolone, a neurosteroid derivative of progesterone, and the gamma-aminobutyric acid (GABA) system represents an important relationship underlying symptom genesis in reproductive-related mood disorders, including PMDD. The objective of this narrative review is to discuss the plausible link between changes in GABAergic transmission secondary to the fluctuation of allopregnanolone during the luteal phase and mood impairment in susceptible individuals. As part of this discussion, we explore promising findings from early clinical trials of several compounds that stabilize allopregnanolone signaling during the luteal phase, including dutasteride, a 5-alpha reductase inhibitor; isoallopregnanolone, a GABA-A modulating steroid antagonist; and ulipristal acetate, a selective progesterone receptor modulator. We then reflect on the implications of these therapeutic advances, including how they may promote our knowledge of affective regulation more generally. We conclude that these and other studies of PMDD may yield critical insight into the etiopathogenesis of affective disorders, considering that (1) symptoms in PMDD have a predictable onset and offset, allowing for examination of affective state kinetics, and (2) GABAergic interventions in PMDD can be used to better understand the relationship between mood states, network regulation, and the balance between excitatory and inhibitory signaling in the brain.

Towards understanding the biology of premenstrual dysphoric disorder: From genes to GABA

Premenstrual dysphoric disorder (PMDD) is a severe mood disorder, with affective symptoms that rise and fall in concert with the hormonal fluctuations of the menstrual cycle. PMDD's pathophysiology is poorly understood. This review describes recent research on potential biological contributors to PMDD, with a focus on neuroactive steroids, genetics, neuroimaging and cellular studies. Studies suggest that a key contributor is abnormal central nervous system (CNS) response to fluctuations in neuroactive steroid hormones. Imaging studies are limited but support alterations in serotonergic and GABA transmission. Genetic studies suggest heritability, yet specific genetic contributors have not been characterized. Finally, recent cutting-edge cellular studies indicate an underlying vulnerability to the effect of sex hormones at a cellular level. Overall the findings across studies do not yet fit together into a complete description of the underlying biology of PMDD. It is possible that PMDD consists of biological subtypes, and future research may benefit from a subtyping approach.

Profiling GABA(A) Receptor Subunit Expression in the Hippocampus of PMDD Rat Models Based on TCM Theories

γ-Aminobutyric acid type A receptors (GABAARs) play an important role in cognitive and emotional regulation and are related to the hippocampus. However, little is known regarding patterns of hippocampal GABAAR subunit expression in rat models of premenstrual dysphoric disorder (PMDD). This study investigated the above changes by establishing two PMDD rat models based on Traditional Chinese Medicine (TCM) theories, namely, PMDD liver-qi invasion syndrome (PMDD-LIS) and PMDD liver-qi depression syndrome (PMDD-LDS). Behavioral tests were used to detect depression and irritability emotion. Western blot analysis was used to investigate protein levels of GABAAR α1, α2, α4, α5, β2, β3, and δ subunits, whereas ultra-high performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) analysis was performed to determine gamma-aminobutyric acid (GABA) and glutamate (Glu) levels in the hippocampus across each group. Concurrently, behavioral data indicated that the PMDD-LDS and PMDD-LIS rat models had been successfully established. GABAAR α2, α5, β2, and δ subunit was significantly upregulated, whereas α4 was significantly downregulated (P < 0.05) in PMDD-LDS rat models relative to controls. On the other hand, GABAAR α1, α2, and β3 were significantly downregulated while α4 and β2 were significantly upregulated in PMDD-LIS rat models relative to the control group (P < 0.05). Moreover, GABA levels significantly decreased, while Glu and the ratio of glutamate to GABA increased in PMDD-LIS rat models (P < 0.05). Conversely, GABA and Glu levels significantly decreased, whereas the ratio of glutamate to GABA increased in PMDD-LIS rat models (P < 0.05). Conclusively, our results revealed differential expression of GABAAR α1, α2, α4, α5, β2, β3, and δ subunits between PMDD-LIS and PMDD-LDS rat models, suggesting that they may be biomarkers in the pathogenesis of PMDD.

Progesterone and Its Metabolites Play a Beneficial Role in Affect Regulation in the Female Brain

Premenstrual dysphoric disorder is a female affective disorder that is defined by mood symptoms. The condition is linked to unstable progesterone concentrations. Progestin supplementation is given in cases of threatened or recurrent miscarriage and for luteal phase support. Progesterone is essential for implantation, immune tolerance, and modulation of uterine contractility. For a long time, the administration of progestins was associated with an unfavorable impact on mood, leading to negative affect, and, therefore, was contraindicated in existing mood disorders. Establishing the role of the natural progesterone derivative allopregnanolone in advances in the treatment of postpartum depression has shed new light on the general pathophysiology of mood disorders. Allopregnanolone directly interacts with gamma-aminobutyric acid type A (GABA-A) receptors even at nanomolar concentrations and induces significant anti-depressant, anti-stress, sedative, and anxiolytic effects. Postpartum depression is caused by a rapid drop in hormones and can be instantly reversed by the administration of allopregnanolone. Premenstrual dysphoric disorder can also be considered to result from insufficient neuroactive steroid action due to low progesterone derivative concentration, unstable hormone levels, or decreased receptor sensitivity. The decrease in progesterone levels in perimenopause is also associated with affective symptoms and an exacerbation of some psychosomatic syndromes. Bioidentical progesterone supplementation encounters several obstacles, including limited absorption, first-pass effect, and rapid metabolism. Hence, non-bioidentical progestins with better bioavailability were widely applied. The paradoxical, unfavorable effect of progestins on mood can be explained by the fact that progestins suppress ovulation and disturb the endocrine function of the ovary in the luteal phase. Moreover, their distinct chemical structure prevents their metabolism to neuroactive, mood-improving derivatives. A new understanding of progesterone-related mood disorders can translate the study results from case series and observational studies to cohort studies, clinical trials, and novel, effective treatment protocols being developed.

Biomarkers and treatments for mood disorders encompassing the neurosteroid and endocannabinoid systems

Mood disorders, including major depressive disorder, postpartum depression, post-traumatic stress disorder and suicidality are highly prevalent, associated with a significant economic burden, and remain poorly diagnosed and poorly treated psychiatric conditions. In part, this may result from the lack of biomarkers that can guide precision medicine with individualized treatments for millions of individuals who suffer these debilitating conditions worldwide. While several biomarker candidates have been proposed for mood disorders, none has been implemented in clinical practice and the treatment still relies in the prescription of selective serotonin reuptake inhibitors that shows mixed efficacy and significant side effects. Both neurosteroid biosynthesis and the endocannabinoid system have recently provided evidence for pharmacological targets to improve mood symptoms and the neuroactive steroid allopregnanolone has recently been approved by the USA Food and Drug Administration for the treatment of post-partum depression. Clinical studies also show efficacy for the management of major depression and more studies are being conducted to study efficacy in post-traumatic stress disorder. Likewise, the endocannabinoid-like modulator, N-palmioyl ethanolamide (PEA) has shown efficacy in the treatment of major depression and bipolar disorder. While these new agents are coming forward in the field of neuropsychopharmacology as a new generation of fast-acting antidepressants, the hypothesis of whether their deficits underlying mood disorders could constitute valid predictive biomarkers to facilitate diagnosis and treatment of these conditions is under consideration.

Novel antidepressant drugs: Beyond monoamine targets

Treatment of major depressive disorder (MDD) including treatment-resistant depression (TRD) remains a major unmet need. Although there are several classes of dissimilar antidepressant drugs approved for MDD, the current drugs have either limited efficacy or are associated with undesirable side effects and withdrawal symptoms. The efficacy and side effects of antidepressant drugs are mainly attributed to their actions on different monoamine neurotransmitters (serotonin, norepinephrine, and dopamine). Development of new antidepressants with novel targets beyond the monoamine pathways may fill the unmet need in treatment of MDD and TRD. The recent approval of intranasal Esketamine (glutamatergic agent) in conjunction with an oral antidepressant for the treatment of adult TRD patients was the first step toward expanding beyond the monoamine targets. Several other glutamatergic (AXS-05, REL-1017, AV-101, SLS-002, AGN24175, and PCN-101) and GABAergic (brexanolone, zuranolone, and ganaxolone) drugs are currently in different stages of clinical development for MDD, TRD and other indications. The renaissance of psychedelic drugs and the emergence of preliminary positive clinical trial results with psilocybin, Ayahuasca, 5-methoxy-N,N-dimethyltryptamine (5-MeO-DMT), and lysergic acid diethylamide (LSD) may pave the way towards establishing this class of drugs as effective therapies for MDD, TRD and other neuropsychiatric disorders. Going beyond the monoamine targets appears to be an effective strategy to develop novel antidepressant drugs with superior efficacy, safety, and tolerability for the improved treatment of MDD and TRD.

Premenstrual disorders: Premenstrual syndrome and premenstrual dysphoric disorder

Recently, the term premenstrual disorders (PMDs), which includes premenstrual syndrome and premenstrual dysphoric disorder as a continuum, has been proposed. Although the precise etiology of PMDs remains unknown, the involvement of hormonal fluctuations is clear. The brain transmitters, serotonin and γ-amino butyric acid, also seem to be involved. Serotonin reuptake inhibitors and oral contraceptives are the current mainstay of treatment, but these are insufficient. Even the currently used prospective two-period symptom diary is not widely used in actual clinical practice, creating a major problem of discrepancy between research and clinical practice. In this review, I would like to outline the latest information and problems in the etiology, diagnosis, and treatment of PMDs, with an emphasis on promising new therapies.

Understanding the Role of Oxidative Stress, Neuroinflammation and Abnormal Myelination in Excessive Aggression Associated with Depression: Recent Input from Mechanistic Studies

Aggression and deficient cognitive control problems are widespread in psychiatric disorders, including major depressive disorder (MDD). These abnormalities are known to contribute significantly to the accompanying functional impairment and the global burden of disease. Progress in the development of targeted treatments of excessive aggression and accompanying symptoms has been limited, and there exists a major unmet need to develop more efficacious treatments for depressed patients. Due to the complex nature and the clinical heterogeneity of MDD and the lack of precise knowledge regarding its pathophysiology, effective management is challenging. Nonetheless, the aetiology and pathophysiology of MDD has been the subject of extensive research and there is a vast body of the latest literature that points to new mechanisms for this disorder. Here, we overview the key mechanisms, which include neuroinflammation, oxidative stress, insulin receptor signalling and abnormal myelination. We discuss the hypotheses that have been proposed to unify these processes, as many of these pathways are integrated for the neurobiology of MDD. We also describe the current translational approaches in modelling depression, including the recent advances in stress models of MDD, and emerging novel therapies, including novel approaches to management of excessive aggression, such as anti-diabetic drugs, antioxidant treatment and herbal compositions.

Involvement of the GABAergic system in PTSD and its therapeutic significance

The neurobiological mechanism of post-traumatic stress disorder (PTSD) is poorly understood. The inhibition of GABA neurons, especially in the amygdala, is crucial for the precise regulation of the consolidation, expression, and extinction of fear conditioning. The GABAergic system is involved in the pathophysiological process of PTSD, with several studies demonstrating that the function of the GABAergic system decreases in PTSD patients. This paper reviews the preclinical and clinical studies, neuroimaging techniques, and pharmacological studies of the GABAergic system in PTSD and summarizes the role of the GABAergic system in PTSD. Understanding the role of the GABAergic system in PTSD and searching for new drug targets will be helpful in the treatment of PTSD.

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.

Sex steroid hormones in depressive disorders as a basis for new potential treatment strategies

The sex steroid hormones (SSHs) such as testosterone, estradiol, progesterone, and their metabolites have important organizational and activational impacts on the brain during critical periods of brain development and in adulthood. A variety of slow and rapid mechanisms mediate both organizational and activational processes via intracellular or membrane receptors for SSHs. Physiological concentrations and distribution of SSHs in the brain result in normal brain development. Nevertheless, dysregulation of hormonal equilibrium may result in several mood disorders, including depressive disorders, later in adolescence or adulthood. Gender differences in cognitive abilities, emotions as well as the 2-3 times higher prevalence of depressive disorders in females, were already described. This implies that SSHs may play a role in the development of depressive disorders. In this review, we discuss preclinical and clinical studies linked to SSHs and development of depressive disorders. Our secondary aim includes a review of up-to-date knowledge about molecular mechanisms in the pathogenesis of depressive disorders. Understanding these molecular mechanisms might lead to significant treatment adjustments for patients with depressive disorders and to an amelioration of clinical outcomes for these patients. Nevertheless, the impact of SSHs on the brain in the context of the development of depressive disorders, progression, and treatment responsiveness is complex in nature, and depends upon several factors in concert such as gender, age, comorbidities, and general health conditions.

What we know about the role of corticosteroids in psychiatric disorders; evidence from animal and clinical studies

Corticosteroids, often known as steroids, are anti-inflammatory medicine prescribed for various conditions. There is accumulating evidence of immune dysregulation in major psychiatric disorders. Significant changes in concentrations of inflammatory biomarkers (i.e., IL-6 and TNF-a) have been previously reported in individuals with schizophrenia, autistic individuals, and depressive patients. Thus, systemic corticosteroids can be used as an adjuvant treatment to reduce inflammation in major psychiatric disorders. However, despite their well-known potent anti-inflammatory and immunosuppressant properties, this treatment is often associated with increased severity of several psychiatric symptoms and relapse. This article reviews the available literature on psychiatric and cognitive changes during corticosteroid therapy. Specifically, we will provide data on the good and the bad of corticosteroid therapy in autism, schizophrenia, mood disorders, and PTSD. This review will summarize the vital role of corticosteroid therapy in social and cognitive behavior.

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 \.

Do neurosteroids have impact on depression and cognitive functions in cases with acromegaly?

OBJECTIVE

Neurosteroids (NSs) are a distinct hormone group and, they are known for their contribution into the status of mood and cognitive functions. Whether they are also involved in the mood disturbances and cognition in acromegaly is not known. Herein we aimed to evaluate the relation of mood status and cognitive functions with the NS levels in cases with acromegaly.

DESIGN

A total of 33 cases with acromegaly composed the acromegaly group (AG) and, 30 age and gender-matched cases without acromegaly composed the control group (CG). The levels of Allopregnanolone (AP), pregnenolone (PRG), 24S-hydroxycholesterol (24OHC), dehydroepiandrosterone (DHEA), dehydroepiandrosterone sulfate (DHEAS), androsterone (ADT), GH and IGF-1 were measured in each group. Beck Depression Inventory (BDI) was used to assess depressive symptoms, whereas an extensive neuropsychological assessment with several neurocognitive tests were carried out for each subject by an experienced psychologist.

RESULTS

Cases with acromegaly had lower 24OHC and DHEA levels (p = 0.002 and p = 0.007, respectively) in comparison to CG. Of the cognitive functions time to complete 1 s Series was significantly higher and, the scores on Switching Verbal Fluency Test, Boston Naming Test (BNT)-semantic and BNT-phonological, the highest learning point of Oktem Verbal Memory Processes Test (VMPT) were significantly lower in cases with acromegaly in comparison to those in controls (p = 0.004, p = 0.01, p < 0.001, p = 0.02 and p = 0.05, respectively). KAS-perseveration errors were higher in CG (p = 0.03). In AG the levels of AP were negatively correlated with the scores on Months backward Test (MBT), Animal Naming Test, Construction, BNT-spontaneous and positively correlated with BNT-incorrect answers; PRG was positively correlated with VMPT-retention scores, ADT was negatively correlated with MBT and 3 s Series scores, DHEAS was positively correlated with VMPT-the highest learning point whereas it was negatively correlated with MBT scores. Additionally, the scores on BDI were positively correlated with DHEA levels in AG.

CONCLUSION

Cognitive changes may be encountered in acromegaly and, neurosteroids may contribute to the changes in certain cognitive functions.

Reduced Hippocampal and Anterior Cingulate Expression of Antioxidant Enzymes and Membrane Progesterone Receptors in Alzheimer's Disease with Depression

BACKGROUND

Major depressive disorder (MDD) is a risk factor for dementia including that caused by Alzheimer's disease (AD). Both MDD and AD have a higher prevalence in women than men, and estrogen-related processes have been implicated in this sex difference.

OBJECTIVE

To identify if enhanced oxidative stress and decreased expression of the memory enhancer insulin-like growth factor 2 (IGF2), each implicated separately in MDD and AD, are exaggerated in individuals with both AD and MDD compared to those with AD.

METHODS

Expression of target genes are determined by qPCR in postmortem hippocampus (Hip) and anterior cingulate cortex (ACC) of individuals with dementia and autopsy confirmed AD and those of AD+MDD.

RESULTS

Transcript levels of the antioxidant enzymes catalase (CAT) and superoxide dismutase 1 (SOD1), as well as IGF2 and its receptor (IGF2R) were significantly lower in the Hip and ACC of individuals with both AD and MDD compared to those with AD and no MDD. Expressions of Progestin and AdipoQ Receptor Family Member 7 (PAQR7, alias progesterone receptor alpha, mPRa) and PAQR8 (mPRβ), receptors that bind neurosteroids, were also lower in the Hip and ACC of AD+MDD samples compared to those of AD without MDD. Correlations among these transcripts revealed that estrogen receptor 2 (ESR2) and mPR β are direct or indirect regulators of the expression of the antioxidant enzymes and IGF2R.

CONCLUSION

Reduced levels of antioxidant enzymes, decreased IGF2 expression, and diminished estrogen or membrane progesterone receptor-dependent processes might be more pronounced in the subpopulation of individuals with AD and MDD than without MDD.

The Allopregnanolone Response to Acute Stress in Females: Preclinical and Clinical Studies

The neuroactive steroid allopregnanolone ((3α,5α)-3-hydroxypregnan-20-one or 3α,5α-THP) plays a key role in the response to stress, by normalizing hypothalamic-pituitary-adrenal (HPA) axis function to restore homeostasis. Most studies have been conducted on male rats, and little is known about the allopregnanolone response to stress in females, despite that women are more susceptible than men to develop emotional and stress-related disorders. Here, we provide an overview of animal and human studies examining the allopregnanolone responses to acute stress in females in the context of stress-related neuropsychiatric diseases and under the different conditions that characterize the female lifespan associated with the reproductive function. The blunted allopregnanolone response to acute stress, often observed in female rats and women, may represent one of the mechanisms that contribute to the increased vulnerability to stress and affective disorders in women under the different hormonal fluctuations that occur throughout their lifespan. These studies highlight the importance of targeting neuroactive steroids as a therapeutic approach for stress-related disorders in women.

Pleiotropic endophenotypic and phenotype effects of GABAergic neurosteroid synthesis deficiency in posttraumatic stress disorder

PTSD is associated with deficits in synthesis of progesterone metabolites such as allopregnanolone and pregnanolone that potently facilitate gamma-amino-butyric acid (GABA) effects at GABA_A receptors. These neurosteroids modulate neuronal firing rate, regional brain connectivity, and activation of amygdala-mediated autonomic nervous system, hypothalamic-pituitary-adrenal axis, and behavioral reactions to unconditioned and conditioned threat. They also play critical roles in learning and memory processes such as extinction and extinction retention and inhibit toll-like receptor activation of intracellular pro-inflammatory pathways. Deficient synthesis of these neurosteroids thus may contribute to individually variable PTSD clinical phenotypes encompassing symptom severity, capacity for PTSD recovery, and vulnerability to common PTSD-comorbidities such as major depression, chronic pain, alcohol and nicotine dependence, cardiovascular disease, metabolic syndrome, reproductive disorders, and autoimmune conditions.

Pregnane neurosteroids exert opposite effects on GABA and glycine-induced chloride current in isolated rat neurons

The ability of endogenous neurosteroids (NSs) with pregnane skeleton modified at positions C-3 and C-5 to modulate the functional activity of inhibitory glycine receptors (GlyR) and ionotropic ɣ-aminobutyric acid receptors (GABA_A R) was estimated. The glycine and GABA-induced chloride current (I_Gly and I_GABA ) were measured in isolated pyramidal neurons of the rat hippocampus and in isolated rat cerebellar Purkinje cells, respectively. Our experiments demonstrated that pregnane NSs affected I_GABA and I_Gly in a different manner. At low concentrations (up to 5 μM), tested pregnane NSs increased or did not change the peak amplitude of the I_GABA , but reduced the I_Gly by decreasing the peak amplitude and/or accelerating desensitization. Namely, allopregnanolone (ALLO), epipregnanolone (EPI), pregnanolone (PA), pregnanolone sulfate (PAS) and 5β-dihydroprogesterone (5β-DHP) enhanced the I_GABA in Purkinje cells. Dose-response curves plotted in the concentration range from 1 nM to 100 μM were smooth for EPI and 5β-DHP, but bell-shaped for ALLO, PA and PAS. The peak amplitude of the I_Gly was reduced by PA, PAS, and 5α- and 5β-DHP. In contrast, ALLO, ISO and EPI did not modulate it. Dose-response curves for the inhibition of the I_Gly peak amplitude were smooth for all active compounds. All NSs accelerated desensitization of the I_Gly . The dose-response relationship for this effect was smooth for ALLO, PA, PAS and 5β-DHP, but it was U-shaped for EPI, 5α-DHP and ISO. These results, together with our previous results on NSs with androstane skeleton, offer comprehensive overview for understanding the mechanisms of effects of NSs on I_Gly and I_GABA .

Translocator protein (18kDa) TSPO: a new diagnostic or therapeutic target for stress-related disorders?

Efficient treatment of stress-related disorders, such as depression, is still a major challenge. The onset of antidepressant drug action is generally quite slow, while the anxiolytic action of benzodiazepines is considerably faster. However, their long-term use is impaired by tolerance development, abuse liability and cognitive impairment. Benzodiazepines act as positive allosteric modulators of ɣ-aminobutyric acid type A (GABA_A) receptors. 3α-reduced neurosteroids such as allopregnanolone also are positive allosteric GABA_A receptor modulators, however, through a site different from that targeted by benzodiazepines. Recently, the administration of neurosteroids such as brexanolone or zuranolone has been shown to rapidly ameliorate symptoms in post-partum depression or major depressive disorder. An attractive alternative to the administration of exogenous neurosteroids is promoting endogenous neurosteroidogenesis via the translocator protein 18k Da (TSPO). TSPO is a transmembrane protein located primarily in mitochondria, which mediates numerous biological functions, e.g., steroidogenesis and mitochondrial bioenergetics. TSPO ligands have been used in positron emission tomography (PET) studies as putative markers of microglia activation and neuroinflammation in stress-related disorders. Moreover, TSPO ligands have been shown to modulate neuroplasticity and to elicit antidepressant and anxiolytic therapeutic effects in animals and humans. As such, TSPO may open new avenues for understanding the pathophysiology of stress-related disorders and for the development of novel treatment options.

The underlying sex differences in neuroendocrine adaptations relevant to Myalgic Encephalomyelitis Chronic Fatigue Syndrome

INTRODUCTION

Myalgic Encephalomyelitis/ Chronic Fatigue Syndrome (ME/CFS) is a complex multisystem disease characterised by severe and disabling new-onset symptoms of post-exertional malaise (PEM), fatigue, brain fog, and sleep dysfunction that lasts for at least six months. Accumulating evidence suggests that sex and endocrine events have a significant influence on symptom onset and moderation of ME/CFS, with female sex being one of the most consistent and credible predictive risk factors associated with diagnosis. Such sex differences suggest sex chromosomes and sex steroids may play a part in the development of the condition or moderation of symptoms, although this has yet to be explored in detail.

METHODS/AIMS

This narrative review outlines sex differences in ME/CFS in terms of vulnerability factors and clinical phenotype and explores the known sex differences in neuroendocrine systems affected in ME/CFS and how this may relate to disease risk, onset, pathophysiology, and potential treatment avenues.

CONCLUSIONS

There is clear evidence of a sex dimorphism with regards to prevalence (3:1 female preponderance), clinical phenotypes, and aetiological triggers prior to symptom onset of ME/CFS. Endocrinological events, particularly those throughout the female lifespan, are associated with ME/CFS and include reproductive menstrual cycle fluctuations, pregnancy, post-partum and perimenopause. Further, there is evidence for gonadal sex, adrenal stress and renal neuroendocrine systems as implicated in ME/CFS, including changes in estrogen, progesterone compounds, aldosterone, and cortisol levels, of which there are established sex differences. The broad effects of steroid hormones on the physiological systems may also speak to the diversity of ME/CFS symptomatology observed in patients. Further attention must be paid to sex, age, and steroid biology in ME/CFS.

The adrenal steroid profile in adolescent depression: a valuable bio-readout?

There is preliminary evidence that adrenal steroids other than cortisol may be valuable biomarkers for major depressive disorder (MDD). So far, studies have been conducted in adults only, and conclusions are limited, mainly due to small sample sizes. Therefore, the present study assessed whether adrenal steroids serve as biomarkers for adolescent MDD. In 261 depressed adolescents (170 females) treated at a single psychiatric hospital, serum adrenal steroids (progesterone, 17-hydroxyprogesterone, 21-deoxycortisol, 11-deoxycortisol, cortisol, cortisone, deoxycorticosterone, corticosterone) were determined by liquid chromatography-tandem mass spectrometry. Findings were compared to that of an age- and sex-matched reference cohort (N = 255) by nonparametric analysis of variance. Nonparametric receiver operating characteristics (ROC) analyses were conducted to evaluate the diagnostic performance of single steroids and steroid ratios to classify depression status. Sensitivity analyses considered important confounders of adrenal functioning, and ROC results were verified by cross-validation. Compared to the reference cohort, levels of deoxycorticosterone and 21-deoxycortisol were decreased (P < 0.001). All other glucocorticoid- and mineralocorticoid-related steroids were increased (P < 0.001). The corticosterone to deoxycorticosterone ratio evidenced excellent classification characteristics, especially in females (AUC: 0.957; sensitivity: 0.902; specificity: 0.891). The adrenal steroid metabolome qualifies as a bio-readout reflecting adolescent MDD by a distinct steroid pattern that indicates dysfunction of the hypothalamus-pituitary-adrenal axis. Moreover, the corticosterone to deoxycorticosterone ratio may prospectively qualify to contribute to precision medicine in psychiatry by identifying those patients who might benefit from antiglucocorticoid treatment or those at risk for recurrence when adrenal dysfunction has not resolved.

Investigational Drugs for the Treatment of Depression (Part 1): Monoaminergic, Orexinergic, GABA-Ergic, and Anti-Inflammatory Agents

Therapeutic management of depression has currently important limitations, and its low efficacy is reflected in high rates of non-response even after multiple trials of antidepressants. Almost two-thirds of the patients diagnosed with major depression who received a 4–6 weeks trial of antidepressant could not reach remission, and more than 30% of these patients are considered treatment-resistant. In bipolar depression, the situation is also discouraging if we analyze the high suicide rate, the risk for the treatment-emergent affective switch when antidepressants are added, the high rate of treatment resistance (up to 25%), and the severe functional impairments associated with these episodes. Therefore, new therapeutic agents are needed, as well as new pathogenetic models for depression. The vast majority of the currently approved antidepressants are based on the monoamine hypothesis, although new drugs exploiting different neurotransmitter pathways have been recently approved by FDA. Brexanolone, an allopregnanolone analog, is an example of such new antidepressants, and its approval for post-partum depression inspired the search for a new generation of neurosteroids and GABA-ergic modulators, with an easier way of administration and superior tolerability profile. Orexin receptors antagonists are also extensively studied for different psychiatric disorders, depression included, in phase II trials. Antiinflammatory drugs, both cyclo-oxygenase 2 inhibitors and biological therapy, are investigated in patients with depressive disorders based on the proven correlation between inflammation and mood disorders in preclinical and clinical studies. Also, a new generation of monoamine-based investigational drugs is explored, ranging from triple reuptake inhibitors to atypical antipsychotics, in patients with major depression. In conclusion, there is hope for new treatments in uni- and bipolar depression, as it became clear, after almost seven decades, that new pathogenetic pathways should be targeted to increase these patients’ response rate.

Allopregnanolone in Postpartum Depression

Postpartum depression (PPD) is a debilitating psychiatric disorder characterized by a high worldwide prevalence and serious long-term negative outcomes for both mothers and children. The lack of a specific treatment and overreliance on pharmacotherapy with limited efficacy and delayed treatment response has constituted a complication in the management of PPD. Recently, the Food and Drug Administration (FDA) in the USA approved a synthetic formulation of the GABAergic neurosteroid allopregnanolone, administered intravenously (brexanolone) for the rapid, long-lasting and effective treatment of PPD. Hereinafter, we review findings on allopregnanolone biosynthesis and GABA_A receptor plasticity in the pathophysiology of PPD. We also discuss evidence supporting the efficacy of brexanolone for the treatment of PPD, which opens a promising new horizon for neurosteroid-based therapeutics for mood disorders.

Association of Postpartum Depression with Maternal Suicide: A Nationwide Population-Based Study

BACKGROUND

To examine the association of postpartum depression (PPD) with maternal suicide in the Taiwanese population.

METHODS

We examined the medical records of women aged 18-50 years who experienced childbirth and had PPD (the study cohort, n = 2882), who experienced childbirth but did not have PPD (comparison cohort 1, n = 5764), and who neither experienced childbirth nor had PPD (comparison cohort 2, n = 5764) between 2000 and 2015. The patients were followed up until suicide, withdrawal from the National Health Insurance program, or 31 December 2015.

RESULTS

The rates of anxiety and depression symptoms, as well as the cumulative risk of suicide, were significantly higher in the study cohort. PPD was significantly correlated with an increased risk of maternal suicide and was associated with a greater risk of developing comorbidities such as hypertension, diabetes mellitus, hyperlipidemia, and stroke. The comparison cohorts did not differ significantly in terms of suicide risk.

CONCLUSION

PPD was associated with a significantly higher rate of suicide and a shorter time to suicide after childbirth. Younger age, winter, and subclinical depression and anxiety positively predicted suicide in the study cohort. To prevent maternal suicide, clinicians should be observant of subclinical depression and anxiety symptoms among patients.

A theory of the anxiolytic action of flumazenil in anxiety disorders

BACKGROUND

Anxiety disorders are highly prevalent affecting up to 33.7% of people over a lifetime. Although many treatment options are available, they are often associated with unacceptable side-effect profiles and approximately one in three patients are treatment resistant. Allopregnanolone, a neuroactive steroid acting as a positive allosteric modulator at the GABA_A receptor, is synthesised in response to stress and acts to negatively modulate the hypothalamic-pituitary-adrenal axis.

FINDINGS

After chronic exposure to and withdrawal from allopregnanolone, an increase in α₄β₂δ GABA_A receptors results in a reduced inhibitory effect of allopregnanolone, resulting in decreased inhibition and, therefore, increased neuronal excitability. The relationship between allopregnanolone and increased α₄β₂δ GABA_A receptors has been demonstrated in animal models during methamphetamine withdrawal and puberty, events both associated with stress. The effect of allopregnanolone during these events is anxiogenic, a paradoxical action to its usual anxiolytic effects. Flumazenil, the GABA_A receptor antagonist, has been shown to cause receptor internalisation of α₄β₂δ GABA_A receptors, which may results in anxiolysis.

CONCLUSION

We propose that chronic stress and chronic exposure to and withdrawal from allopregnanolone in anxiety disorders result in alterations in GABA_A receptor function, which can be corrected by flumazenil. As such, flumazenil may exhibit anxiolytic properties in patients with increased α₄β₂δ GABA_A receptor expression.

Systematic review of sex differences in the relationship between hormones and depression in HIV

BACKGROUND

Major depressive disorder is the most common neuropsychiatric comorbidity of human immunodeficiency virus (HIV), and women are more frequently affected in the general population and among those with HIV. The rate of depression in HIV is three times higher than the general population. Differences in biomarkers in neuroendocrine and inflammatory pathways are one possible explanation for the increased prevalence of depression in individuals with HIV, especially biological women. Therefore, we aimed to perform a systematic review identifying differences in neuroendocrine factors leading to depression in men versus women with HIV.

METHODS

A comprehensive search of 8 databases was performed, followed by title and abstract screening and later full-text screening by two independent researchers. A risk of bias assessment was completed.

RESULTS

Twenty-six full-text articles were included in the review. Significant correlations between depression and neuroendocrine marker levels were found for cortisol (both sexes), testosterone (only in men), oxytocin (only tested in women), and estradiol (only in women). No significant correlation between depression and hormone level was found for prolactin, dehydroepiandrosterone (DHEAS), or sex hormone binding globulin (SHBG). Nearly all studies included only men or women and did not directly compare neuroendocrine markers between the two sexes. One study found that the correlation between cortisol levels and depression scores was stronger in women than men.

CONCLUSION

Neuroendocrine systems are highly active in the brain and important in the development and persistence of mental illness. Given that HIV can, directly and indirectly, impact hormone signaling, it is likely contributing to the high rate of depression in individuals with HIV. However, few studies explore neuroactive hormones in depression and HIV, nor how this connection may differ between the sexes. More high-quality research is needed in this area to explore the link further and inform possible avenues of treatment.

Preventing Phosphorylation of the GABAAR β3 Subunit Compromises the Behavioral Effects of Neuroactive Steroids

Neuroactive steroids (NASs) have potent anxiolytic, anticonvulsant, sedative, and hypnotic actions, that reflect in part their efficacy as GABA_AR positive allosteric modulators (PAM). In addition to this, NAS exert metabotropic effects on GABAergic inhibition via the activation of membrane progesterone receptors (mPRs), which are G-protein coupled receptors. mPR activation enhances the phosphorylation of residues serine 408 and 409 (S408/9) in the β3 subunit of GABA_ARs, increasing their accumulation in the plasma membrane leading to a sustained increase in tonic inhibition. To explore the significance of NAS-induced phosphorylation of GABA_ARs, we used mice in which S408/9 in the β3 subunit have been mutated to alanines, mutations that prevent the metabotropic actions of NASs on GABA_AR function while preserving NAS allosteric potentiation of GABAergic current. While the sedative actions of NAS were comparable to WT, their anxiolytic actions were reduced in S408/9A mice. Although the induction of hypnosis by NAS were maintained in the mutant mice the duration of the loss of righting reflex was significantly shortened. Finally, ability of NAS to terminate diazepam pharmacoresistant seizures was abolished in S408/9A mice. In conclusion, our results suggest that S408/9 in the GABA_AR β3 subunit contribute to the anxiolytic and anticonvulsant efficacy of NAS, in addition to their ability to regulate the loss of righting reflex.

Deficiency of Glycosylated α-Dystroglycan in Ventral Hippocampus Bridges the Destabilization of Gamma-Aminobutyric Acid Type A Receptors With the Depressive-like Behaviors of Male Mice

BACKGROUND

Depression is a common psychiatric disorder associated with defects in GABAergic (gamma-aminobutyric acidergic) neurotransmission. α-Dystroglycan (α-DG), a cell adhesion molecule known to be essential for skeletal muscle integrity, is also present at inhibitory synapses in the central nervous system and forms a structural element in certain synapses. However, the role of α-DG in the regulation of depressive-like behaviors remains largely unknown.

METHODS

Depressive-like behaviors were induced by chronic social defeat stress in adult male mice. Surface protein was extracted by a biotin kit, and the expression of protein was detected by Western blotting. Intrahippocampal microinjection of the lentivirus or adeno-associated virus or agrin intervention was carried out using a stereotaxic instrument and followed by behavioral tests. Miniature inhibitory postsynaptic currents were recorded by whole-cell patch-clamp techniques.

RESULTS

The expression of α-DG and glycosylated α-DG in the ventral hippocampus was significantly lower in chronic social defeat stress-susceptible male mice than in control mice, accompanied by a decreased surface expression of GABA_A receptor γ2 subunit and reduced GABAergic neurotransmission. RNA interference-mediated knockdown of Dag1 increased the susceptibility of mice to subthreshold stress. Both in vivo administration of agrin and overexpression of like-acetylglucosaminyltransferase ameliorated depressive-like behaviors and restored the decrease in surface expression of GABA_A receptor γ2 subunit and the amplitude of miniature inhibitory postsynaptic currents in chronic social defeat stress-exposed mice.

CONCLUSIONS

Our findings demonstrate that glycosylated α-DG plays a role in the pathophysiological process of depressive-like behaviors by regulating the surface expression of GABA_A receptor γ2 subunit and GABAergic neurotransmission in the ventral hippocampus.

The Problem of Malnutrition Associated with Major Depressive Disorder from a Sex-Gender Perspective

Major depressive disorder (MDD) is an incapacitating condition characterized by loss of interest, anhedonia and low mood, which affects almost 4% of people worldwide. With rising prevalence, it is considered a public health issue that affects economic productivity and heavily increases health costs alone or as a comorbidity for other pandemic non-communicable diseases (such as obesity, cardiovascular disease, diabetes, inflammatory bowel diseases, etc.). What is even more noteworthy is the double number of women suffering from MDD compared to men. In fact, this sex-related ratio has been contemplated since men and women have different sexual hormone oscillations, where women meet significant changes depending on the age range and moment of life (menstruation, premenstruation, pregnancy, postpartum, menopause…), which seem to be associated with susceptibility to depressive symptoms. For instance, a decreased estrogen level promotes decreased activation of serotonin transporters. Nevertheless, sexual hormones are not the only triggers that alter neurotransmission of monoamines and other neuropeptides. Actually, different dietary habits and/or nutritional requirements for specific moments of life severely affect MDD pathophysiology in women. In this context, the present review aims to descriptively collect information regarding the role of malnutrition in MDD onset and course, focusing on female patient and especially macro- and micronutrient deficiencies (amino acids, ω3 polyunsaturated fatty acids (ω3 PUFAs), folate, vitamin B12, vitamin D, minerals…), besides providing evidence for future nutritional intervention programs with a sex-gender perspective that hopefully improves mental health and quality of life in women.

Allopregnanolone: The missing link to explain the effects of stress on tic exacerbation?

The neurosteroid allopregnanolone (3α-hydroxy-5α-pregnan-20-one; AP) elicits pleiotropic effects in the central nervous system, ranging from neuroprotective and anti-inflammatory functions to the regulation of mood and emotional responses. Several lines of research show that the brain rapidly produces AP in response to acute stress to reduce the allostatic load and enhance coping. These effects not only are likely mediated by GABA_A receptor activation but also result from the contributions of other mechanisms, such as the stimulation of membrane progesterone receptors. In keeping with this evidence, AP has been shown to exert rapid, potent antidepressant properties and has been recently approved for the therapy of moderate-to-severe postpartum depression. In addition to depression, emerging evidence points to the potential of AP as a therapy for other neuropsychiatric disorders, including anxiety, seizures, post-traumatic stress disorder and cognitive problems. Although this evidence has spurred interest in further therapeutic applications of AP, some investigations suggest that this neurosteroid may also be associated with adverse events in specific disorders. For example, our group has recently documented that AP increases tic-like manifestations in several animal models of tic disorders; furthermore, our results indicate that inhibiting AP synthesis and signalling reduces the exacerbation of tic severity associated with acute stress. Although the specific mechanisms of these effects remain partially elusive, our findings point to the possibility that the GABAergic activation by AP may also lead to disinhibitory effects, which could interfere with the ability of patients to suppress their tics. Future studies will be necessary to verify whether these mechanisms may apply to other externalising manifestations, such as impulse-control problems and manic symptoms.

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.

Association between premenstrual dysphoric disorder and perinatal depression: a systematic review

Premenstrual dysphoric disorder (PMDD) affects 1.2 to 5% of women of reproductive age. Besides significant suffering and social, occupational, and interpersonal impairment, it has been suggested that this syndrome is associated with other affective disorders, in different reproductive phases, such as pregnancy and the postpartum period. However, the literature on this association is scarce and presents great variability in terms of adopted methodology and mixed results. To analyze the relationship between PMDD and other affective disorders, aiming to contribute to the clarification of whether PMDD can be considered a risk factor for perinatal depression (PND). Following Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines, we conducted a comprehensive literature search in PubMed, EMBASE, CINAHL, PsycINFO databases. Seven original studies were included. Only one study linked PMDD with depression during pregnancy, with evidence of a positive association between PMDD and PND. This and five other studies show a positive relationship between PMDD and postpartum depression (PPD), assessed in periods ranging from 2 to 4 days to 1 year after birth. Only one study found no significant association between PMDD and PPD, assessed at 4 weeks postpartum. There seems to be a positive and significant association between PMDD and the development of perinatal depression, particularly postpartum depression. This review supports the relevance of health professionals systematically evaluating the presence of premenstrual dysphoric disorder, when monitoring women throughout the perinatal period.

Neurosteroid replacement therapy for catamenial epilepsy, postpartum depression and neuroendocrine disorders in women

Neurosteroids are involved in the pathophysiology of many neuroendocrine disorders in women. This review describes recent advancements in pharmacology of neurosteroids and emphasizes the benefits of neurosteroid replacement therapy for the management of neuroendocrine disorders such as catamenial epilepsy (CE), postpartum depression (PPD) and premenstrual brain conditions. Neurosteroids are endogenous modulators of neuronal excitability. A variety of neurosteroids are present in the brain including allopregnanolone (AP), allotetrahydro-deoxycorticosterone and androstanediol. Neurosteroids interact with synaptic and extrasynaptic GABA_A receptors in the brain. AP and related neurosteroids, which are positive allosteric modulators of GABA_A receptors, are powerful anticonvulsants, anxiolytic, antistress and neuroprotectant agents. In CE, seizures are most often clustered around a specific menstrual period in women. Neurosteroid withdrawal-linked plasticity in extrasynaptic receptors has been shown to play a key role in catamenial seizures, anxiety and other mood disorders. Based on our extensive research spanning two decades, we have proposed and championed neurosteroid replacement therapy as a rational strategy for treating disorders marked by neurosteroid-deficiency, such as CE and other related ovarian or menstrual disorders. In 2019, AP (renamed as brexanolone) was approved for treating PPD. A variety of synthetic neurosteroids are in clinical trials for epilepsy, depression and other brain disorders. Recent advancements in our understanding of neurosteroids have entered a new era of drug discovery and one that offers a high therapeutic potential for treating complex brain disorders.