FRONTIERS IN NEUROENDOCRINOLOGY

The oxytocin system in patients with craniopharyngioma: A systematic review
Mann A, Kalitsi J, Jani K, Martins D, Kapoor RR and Paloyelis Y
Craniopharyngioma is a benign tumour affecting the hypothalamic and pituitary regions, which are involved in the production and secretion of oxytocin. We conducted a systematic review to assess dysregulation of the oxytocin system in craniopharyngioma and associations with neurobehavioural, eating, and metabolic abnormalities. Eight studies (n = 72 patients) were included. Evidence for dysfunction of the endogenous oxytocin system in craniopharyngioma is limited and mixed. While no significant differences in baseline salivary oxytocin concentrations were reported between patients with craniopharyngioma and controls, patients with craniopharyngioma were found to have blunted salivary oxytocin response following exercise stimulation and this was associated with greater state anxiety and higher BMI. Studies administering exogenous oxytocin are sparse and do not meet required standards. Hypothalamic damage may pose an additional mechanism of oxytocin dysregulation. Improving understanding of the oxytocin system in craniopharyngioma could be pivotal for exploring the potential therapeutic role of exogenous oxytocin in this condition.
Progestagens and progesterone receptor modulation: Effects on the brain, mood, stress, and cognition in females
Bencker C, Gschwandtner L, Nayman S, Grikšienė R, Nguyen B, Nater UM, Guennoun R, Sundström-Poromaa I, Pletzer B, Bixo M and Comasco E
Progesterone is a highly lipophilic gonadal hormone that can influence behavior and mental health through its receptors in the brain. Fluctuations in progesterone levels across critical periods of a females life are associated with increased susceptibility to mental conditions. This review highlights the effects of progestagens, including progesterone and synthetic progestins, on the brain, mood, stress, and cognition in females. The primary focus is on experimental pharmacological research that teases out the distinct effects of progestagens from those of estrogens. Additionally, the key literature on puberty, the menstrual cycle, pregnancy, perimenopause, hormonal contraceptives, and menopausal hormone therapy is reviewed, although conclusions are limited by the nested effects of progestagens and estrogens. Single study-findings suggest an influence of progesterone on amygdala reactivity related to processing of emotional stimuli and memory. In patients with premenstrual dysphoric disorder, progesterone receptor modulation improves premenstrual mood symptoms and potentially enhances fronto-cingulate control over emotion processing. The interaction between progestagens and the systems involved in the regulation of stress seems to influence subjective experiences of mood and stress. Sparse studies investigating the effects of progestin-only contraceptives suggest effects of progestagens on the brain, mood, and stress. Progesterone and progestins used for contraception can influence neural processes as myelination and neuroprotection, exerting protective effects against stroke. Concerning menopausal hormonal therapy, the effects of progestins are largely unknown. Levels of progesterone as well as type, administration route, timing, dose regimen, metabolism, and intracellular activity of progestins in hormonal contraceptives and menopausal hormonal therapy are factors whose effects remain to be elucidated. Altogether, current knowledge highlights the potential role of progestagens in females health but also calls for well-designed pharmaco-behavioral studies disentangling the effects of progestagens from those of estrogens.
Insulin-like growth factor-1 and cognitive health: Exploring cellular, preclinical, and clinical dimensions
Hayes CA, Wilson D, De Leon MA, Mustapha MJ, Morales S, Odden MC and Ashpole NM
Age and insulin-like growth factor-1 (IGF-1) have an inverse association with cognitive decline and dementia. IGF-1 is known to have important pleiotropic functions beginning in neurodevelopment and extending into adulthood such as neurogenesis. At the cellular level, IGF-1 has pleiotropic signaling mechanisms through the IGF-1 receptor on neurons and neuroglia to attenuate inflammation, promote myelination, maintain astrocytic functions for homeostatic balances, and neuronal synaptogenesis. In preclinical rodent models of aging and transgenic models of IGF-1, increased IGF-1 improves cognition in a variety of behavioral paradigms along with reducing IGF-1 via knockout models being able to induce cognitive impairment. At the clinical levels, most studies highlight that increased levels of IGF-1 are associated with better cognition. This review provides a comprehensive and up-to-date evaluation of the association between IGF-1 and cognition at the cellular signaling levels, preclinical, and clinical levels.
Unraveling sex differences in maternal and paternal care impacts on social behaviors and neurobiological responses to early-life adversity
Walker SL and Glasper ER
Early-life stress (ELS) affects the development of prosocial behaviors and social-cognitive function, often leading to structural brain changes and increased psychosocial disorders. Recent studies suggest that mother- and father-child relationships independently influence social development in a sex-specific manner, but the effects of impaired father-child relationships are often overlooked. This review examines preclinical rodent studies to explore how parental neglect impacts neuroplasticity and social behaviors in offspring. We highlight that disruptions in maternal interactions may affect male pups more in uniparental rodents, while impaired paternal interactions in biparental rodents tend to impact female pups more. Due to limited research, the separate effects of maternal and paternal neglect on brain development and social behaviors in biparental species remain unclear. Addressing these gaps could clarify the sex-specific mechanisms underlying social and neurobiological deficits following parental neglect.
Neurosteroid replacement approaches for improving outcomes after compromised pregnancies and preterm birth
Hirst JJ, Palliser HK, Pavy C, Shaw JC and Moloney RA
The levels of the key neurosteroid of pregnancy, allopregnanolone, are very high in the fetal and maternal brain compared to after birth. These levels are maintained by the placenta which forms a placental connection to fetal brain development. Maternal stresses depress placental synthesis resulting in a fall in allopregnanolone levels leading deficits in myelination that continue into childhood. This contributes to an increased incidence of behavioural disorders. Supplementing neurosteroid action with allopregnanolone analogues or raising endogenous production with mitochondrial translocator protein (TSPO) ligands reverses these deficits. Preterm birth leads to an early dramatic loss of neurosteroid support for brain development leading to marked deficits in myelination and susceptibility to hypoxic-ischaemic injury. Postnatal treatment with the allopregnanolone analogue ganaxolone improves myelination and reduces hyperactive behaviour. TSPO ligands such as emapunil have been shown to improve oligodendrocyte maturation. These findings support the use of allopregnanolone supplementation approaches after pregnancy compromises to improve outcome.
Endocrine disrupting effects on morphological synaptic plasticity
Zsarnovszky A, Alymbaeva D, Jocsak G, Szabo C, Mária Schilling-Tóth B and Sandor Kiss D
Neural regulation of the homeostasis depends on healthy synaptic function. Adaptation of synaptic functions to physiological needs manifests in various forms of synaptic plasticity (SP), regulated by the normal hormonal regulatory circuits. During the past several decades, the hormonal regulation of animal and human organisms have become targets of thousands of chemicals that have the potential to act as agonists or antagonists of the endogenous hormones. As the action mechanism of these endocrine disrupting chemicals (EDCs) came into the focus of research, a growing number of studies suggest that one of the regulatory avenues of hormones, the morphological form of SP, may well be a neural mechanism affected by EDCs. The present review discusses known and potential effects of some of the best known EDCs on morphological synaptic plasticity (MSP). We highlight molecular mechanisms altered by EDCs and indicate the growing need for more research in this area of neuroendocrinology.
Melatonin and brain barriers: The protection conferred by melatonin to the blood-brain barrier and blood-cerebrospinal fluid barrier
Mineiro R, Rodrigues Cardoso M, Catarina Duarte A, Santos C, Cipolla-Neto J, Gaspar do Amaral F, Costa D and Quintela T
The blood-brain barrier and the blood-cerebrospinal fluid barrier separate the blood from brain tissue and cerebrospinal fluid. These brain barriers are important to maintain homeostasis and complex functions by protecting the brain from xenobiotics and harmful endogenous compounds. The disruption of brain barriers is a characteristic of neurologic diseases. Melatonin is a lipophilic hormone that is mainly produced by the pineal gland. The blood-brain barrier and the blood-cerebrospinal fluid barriers are melatonin-binding sites. Among the several melatonin actions, the most characteristic one is the regulation of sleep-wake cycles, melatonin has anti-inflammatory and antioxidant properties. Since brain barriers disruption can arise from inflammation and oxidative stress, knowing the influence of melatonin on the integrity of brain barriers is extremely important. Therefore, the objective of this review is to gather and discuss the available literature about the regulation of brain barriers by melatonin.
Brain alteration of autoimmune thyroid disease: Neuropsychiatric impact, neuroimaging insights, and neurobiological implications
Wei Q, Zhang H, Guan H, Song X and Zhou H
Autoimmune thyroid disease (AITD) is the most common organ-specific autoimmune disease, characterized by thyroid function disorder and autoimmune imbalance. Previous studies have demonstrated the decreased quality of life and neuropsychiatric manifestations in AITD patients, including anxiety, depression, cognitive impairment and affective disorder. These problems also plague the euthyroid AITD patients. Advanced neuroimaging techniques were well carried out and employed as an explanatory instrument for the above intriguing phenomenon. In recent years, an increasing number of neuroimaging studies have reported that these neuropsychiatric manifestations are accompanied by significant structural and functional brain alterations in AITD patients, mainly involved in neurocognitive and emotional regions, despite the underlying neurobiological mechanism is still unclear. The existing studies suggest that the potential pathogenesis of the neuropsychiatric manifestations and brain alterations does not depend on a single factor, but may result from a combination of thyroid function dysfunction, metabolic disorders, dysregulated autoimmune and trans-synaptic degeneration.
Effect of 5-alpha reductase inhibitors in animal models of Parkinson's disease
Bourque M, Morissette M, Isenbrandt A, Giatti S, Melcangi RC, Carta M, Frau R, Bortolato M, Soulet D and Di Paolo T
Parkinson's disease (PD) is characterized by motor symptoms due to loss of brain dopamine and non-motor symptoms, including gastrointestinal disorders. Although there is no cure for PD, symptomatic treatments are available. L-Dopa is the gold standard PD therapy, but most patients develop dyskinesias (LID), which are challenging to manage. Amantadine is recognized as the most effective drug for LID, but its adverse effects limit the use in patients. Here we review how 5α-reductase inhibitors (5ARIs), drugs used to treat benign prostatic hyperplasia and alopecia, exhibit beneficial effects in PD animal models. 5ARIs show neuroprotective properties in brain and gut dopaminergic systems, and reduce dyskinesias in rodent model of PD. Additionally, the 5ARI finasteride dampened dopaminergic-induced drug gambling in PD patients. Neuroprotection and antidyskinetic activities of 5ARIs in animal models of PD suggest their potential repurposing in men with PD to address gut dysfunction, protect brain DA and inhibit dyskinesias.
Astrogenesis in the hypothalamus: A life-long process contributing to the development and plasticity of neuroendocrine networks
Sharif A and Prevot V
Astrocytes are now recognized as integral components of neural circuits, regulating their maturation, activity and plasticity. Neuroendocrinology has provided fertile ground for revealing the diverse strategies used by astrocytes to regulate the physiological and behavioural outcomes of neural circuit activity in response to internal and environmental inputs. However, the development of astrocytes in the hypothalamus has received much less attention than in other brain regions such as the cerebral cortex and spinal cord. In this review, we synthesize our current knowledge of astrogenesis in the hypothalamus across various life stages. A distinctive feature of hypothalamic astrogenesis is that it persists all throughout lifespan, and involves multiple cellular sources corresponding to radial glial cells during early development, followed by tanycytes, parenchymal progenitors and locally dividing astrocytes. Astrogenesis in the hypothalamus is closely coordinated with the maturation of hypothalamic neurons. This coordination is exemplified by recent findings in neurons producing gonadotropin-releasing hormone, which actively shape their astroglial environment during infancy to integrate functionally into their neural network and facilitate sexual maturation, a process vulnerable to endocrine disruption. While hypothalamic astrogenesis shares common principles with other brain regions, it also exhibits specific features in its dynamics and regulation, both at the inter- and intra-regional levels. These unique properties emphasize the importance of further exploration. Additionally, we discuss the experimental strategies used to assess astrogenesis in the hypothalamus and their potential bias and limitations. Understanding the mechanisms of hypothalamic astrogenesis throughout life will be crucial for comprehending the development and function of the hypothalamus under both physiological and pathological conditions.
Hypothalamic neurons fully or partially expressing the dopaminergic phenotype: development, distribution, functioning and functional significance. A review
Ugrumov MV
The hypothalamus is a key link in neuroendocrine regulations, which are provided by neuropeptides and dopamine. Until the late 1980 s, it was believed that, along with peptidergic neurons, hypothalamus contained dopaminergic neurons. Over time, it has been shown that besides dopaminergic neurons expressing the dopamine transporter and dopamine-synthesizing enzymes - tyrosine hydroxylase (TH) and aromatic L-amino acid decarboxylase (AADC) - the hypothalamus contains neurons expressing only TH, only AADC, both enzymes or only dopamine transporter. The end secretory product of TH neurons is L-3,4-dihydroxyphenylalanine, while that of AADC neurons and bienzymatic neurons lacking the dopamine transporter is dopamine. During ontogenesis, especially in the perinatal period, monoenzymatic neurons predominate in the hypothalamic neuroendocrine centers. It is assumed that L-3,4-dihydroxyphenylalanine and dopamine are released into the neuropil, cerebral ventricles, and blood vessels, participating in the regulation of target cell differentiation in the perinatal period and the functioning of target cells in adulthood.
Is melanin-concentrating hormone in the medial preoptic area a signal for the decline of maternal care in late postpartum?
Li M
This manuscript proposes that melanin-concentrating hormone (MCH) in the medial preoptic area (MPOA) is an neurochemical signal evolved to trigger the declining process of maternal care. MCH in the MPOA appears only after parturition and is progressively increased with the progression of lactation, while maternal behavior declines progressively. Intra-MPOA injection of MCH decreases active maternal responses. MCH is also highly responsive to infant characteristics and maternal condition. Behavioral changes induced by MCH in late postpartum period are conducive to the decline of infant-directed maternal behavior. The MPOA MCH system may mediate the maternal behavior decline by suppressing the maternal approach motivation and/or increasing maternal withdrawal via its inhibitory action onto the mesolimbic dopamine D/D receptors and its stimulating action on serotonin 5-HT receptors in the ventral tegmental area. Research into the MCH maternal effects will enhance our understanding of the neurochemical mechanisms underlying the maternal behavior decline.
Novel insights into the activating transcription factor 4 in Alzheimer's disease and associated aging-related diseases: Mechanisms and therapeutic implications
Zhang N, Nao J, Zhang S and Dong X
Ageing is inherent to all human beings, most mechanistic explanations of ageing results from the combined effects of various physiological and pathological processes. Additionally, aging pivotally contributes to several chronic diseases. Activating transcription factor 4 (ATF4), a member of the ATF/cAMP response element-binding protein family, has recently emerged as a pivotal player owing to its indispensable role in the pathophysiological processes of Alzheimer's disease and aging-related diseases. Moreover, ATF4 is integral to numerous biological processes. Therefore, this article aims to comprehensively review relevant research on the role of ATF4 in the onset and progression of aging-related diseases, elucidating its potential mechanisms and therapeutic approaches. Our objective is to furnish scientific evidence for the early identification of risk factors in aging-related diseases and pave the way for new research directions for their treatment. By elucidating the signaling pathway network of ATF4 in aging-related diseases, we aspire to gain a profound understanding of the molecular and cellular mechanisms, offering novel strategies for addressing aging and developing related therapeutics.
Emotion recognition and regulation in males: Role of sex and stress steroids
Ilkevič E, Hausmann M and Grikšienė R
Understanding emotions in males is crucial given their higher susceptibility to substance use, interpersonal violence, and suicide compared to females. Steroid hormones are assumed to be critical biological factors that affect and modulate emotion-related behaviors, together with psychological and social factors. This review explores whether males' abilities to recognize emotions of others and regulate their own emotions are associated with testosterone, cortisol, and their interaction. Higher levels of testosterone were associated with improved recognition and heightened sensitivity to threatening faces. In contrast, higher cortisol levels positively impacted emotion regulation ability. Indirect evidence from neuroimaging research suggested a link between higher testosterone levels and difficulties in cognitive emotion regulation. However, this notion must be investigated in future studies using different emotion regulation strategies and considering social status. The present review contributes to the understanding of how testosterone and cortisol affect psychological well-being and emotional behavior in males.
The emerging role of rapid corticosteroid actions on excitatory and inhibitory synaptic signaling in the brain
Joëls M, Karst H and Tasker JG
Over the past two decades, there has been increasing evidence for the importance of rapid-onset actions of corticosteroid hormones in the brain. Here, we highlight the distinct rapid corticosteroid actions that regulate excitatory and inhibitory synaptic transmission in the hypothalamus, the hippocampus, basolateral amygdala, and prefrontal cortex. The receptors that mediate rapid corticosteroid actions are located at or close to the plasma membrane, though many of the receptor characteristics remain unresolved. Rapid-onset corticosteroid effects play a role in fast neuroendocrine feedback as well as in higher brain functions, including increased aggression and anxiety, and impaired memory retrieval. The rapid non-genomic corticosteroid actions precede and complement slow-onset, long-lasting transcriptional actions of the steroids. Both rapid and slow corticosteroid actions appear to be indispensable to adapt to a continuously changing environment, and their imbalance can increase an individual's susceptibility to psychopathology.
The research landscape concerning environmental factors in neurodevelopmental disorders: Endocrine disrupters and pesticides-A review
Sánchez RM, Bermeo Losada JF and Marín Martínez JA
In recent years, environmental epidemiology and toxicology have seen a growing interest in the environmental factors that contribute to the increased prevalence of neurodevelopmental disorders, with the purpose of establishing appropriate prevention strategies. A literature review was performed, and 192 articles covering the topic of endocrine disruptors and neurodevelopmental disorders were found, focusing on polychlorinated biphenyls, polybrominated diphenyl ethers, bisphenol A, and pesticides. This study contributes to analyzing their effect on the molecular mechanism in maternal and infant thyroid function, essential for infant neurodevelopment, and whose alteration has been associated with various neurodevelopmental disorders. The results provide scientific evidence of the association that exists between the environmental neurotoxins and various neurodevelopmental disorders. In addition, other possible molecular mechanisms by which pesticides and endocrine disruptors may be associated with neurodevelopmental disorders are being discussed.
From means to meaning in the study of sex/gender differences and similarities
Sanchis-Segura C and Wilcox RR
The incorporation of sex and gender (S/G) related factors is commonly acknowledged as a necessary step to advance towards more personalized diagnoses and treatments for somatic, psychiatric, and neurological diseases. Until now, most attempts to integrate S/G-related factors have been reduced to identifying average differences between females and males in behavioral/ biological variables. The present commentary questions this traditional approach by highlighting three main sets of limitations: 1) Issues stemming from the use of classic parametric methods to compare means; 2) challenges related to the ability of means to accurately represent the data within groups and differences between groups; 3) mean comparisons impose a results' binarization and a binary theoretical framework that precludes advancing towards precision medicine. Alternative methods free of these limitations are also discussed. We hope these arguments will contribute to reflecting on how research on S/G factors is conducted and could be improved.
Celebrating 60 years of neuroendocrinology
Galea LAM
Editorial- State of the art on steroids and the nervous system: In memory of Giancarlo
Melcangi RC, Giatti S and Gotti S
Nestorone (segesterone acetate) effects on neuroregeneration
Sitruk-Ware R, Sussman H, Brinton R, Schumacher M, Singer P, Kumar N, De Nicola AF, El-Etr M, Guennoun R and V Borlongan C
Nestorone® (segesterone acetate) is a progestin with a chemical structure closely related to progesterone with high affinity and selectivity for the progesterone receptor without significant interaction with other steroid receptors. It has been developed for female and male contraception and is FDA-approved in a first long-acting contraceptive vaginal system for female contraception. Its safety has been extensively demonstrated in both preclinical and clinical studies for contraceptive indications. Nestorone was found to display neuroprotective and neuroregenerative activity in animal models of various central nervous system diseases, including multiple sclerosis, stroke, and amyotrophic lateral sclerosis. Reviewed herein are neuroprotective and myelin- regenerating properties of Nestorone in various animal models and its translational potential as a therapeutic agent for debilitating neurological diseases for which limited therapeutic options are available (Table 1).
Sex and gender in health research: intersectionality matters
Subramaniapillai S, Am Galea L, Einstein G and de Lange AM
Research policies aiming to integrate sex and gender in scientific studies are receiving increased attention in academia. Incorporating these policies into health research is essential for improving targeted and equitable healthcare outcomes, by considering both disparities and similarities between individuals relating to sex and gender. Although these efforts are both urgent and critical, only an intersectional approach, which considers broad and multidimensional aspects of an individual's identity, can provide a complete understanding of the factors that impact health. In this commentary, we emphasize that it is crucial to examine how sex and gender intersect with factors such as culture, ethnicity, minority status, and socioeconomic conditions to influence health outcomes. To approach health equity, we must consider disparities linked to both biological and environmental factors, in order to facilitate evidence-based health interventions with tangible impact.