60 YEARS OF NEUROENDOCRINOLOGY: The hypothalamo-pituitary-gonadal axis

Serum kisspeptin as a promising biomarker for PCOS: a mini review of current evidence and future prospects

Polycystic ovary syndrome (PCOS) is a prevalent endocrine disorder affecting women of reproductive age, characterised by its multifactorial nature and intricate interplay of genetic, hormonal, and environmental factors. As the search for reliable biomarkers intensifies, serum kisspeptin emerges as a promising candidate due to its central role in regulating the hypothalamic-pituitary-gonadal (HPG) axis. This review aims to consolidate the evolving understanding of kisspeptin as a potential PCOS biomarker, comprehensively exploring its physiological basis, diagnostic challenges in PCOS, and clinical implications. Diagnostic challenges in PCOS are addressed, underscoring the limitations of current criteria and the need for objective and standardised biomarkers. Kisspeptin's introduction as a potential biomarker brings forth both promises and challenges in terms of its diagnostic utility. The review recognises the importance of standardisation in research methodologies and emphasises the exploration of genetic polymorphisms to enhance kisspeptin's robustness as a diagnostic tool.

Organophosphate pesticide chlorpyrifos and its metabolite 3,5,6-trichloropyridinol downregulate the expression of genes essential for spermatogenesis in caprine testes

Organophosphate pesticides have potent endocrine disrupting effects, hence banned in many countries. However, many organophosphates like chlorpyrifos, malathion et cetera continue to be used in some countries (Wołejko et al., 2022; Wołejko et al., 2022)including India. Fodder mediated ingestion of these substances may be harmful for livestock fertility. We have investigated the effect of the widely used organophosphate pesticide chlorpyrifos (CPF) and its metabolite, 3,5,6-trichloropyridinol (TCPy) on the expression of genes essential for spermatogenesis in goat testicular tissue. The testicular Sertoli cells (Sc) regulate germ cell division and differentiation under the influence of follicle stimulating hormone (FSH) and testosterone (T). Impaired FSH and T mediated signalling in Sc can compromise spermatogenesis leading to sub-fertility/infertility. As Sc express receptors (R) for FSH and T, they are highly susceptible to the endocrine disrupting effects of pesticides affecting fertility by dysregulating the functioning of Sc. Our results indicated that exposure to different concentrations of CPF and TCPy can compromise Sc function by downregulating the expression of FSHR and AR which was associated with a concomitant decline in the expression of genes essential for germ cell division and differentiation, like KITLG, INHBB, CLDN11 and GJA1. CPF also induced a significant reduction in the activity of acetylcholinesterase in the testes and increased the total testicular antioxidant capacity. Our results suggested that CPF and its metabolite TCPy may induce reproductive toxicity by dysregulating the expression of Sc specific genes essential for spermatogenesis.

Synaptic connectome of a neurosecretory network in the Drosophila brain

Hormones mediate inter-organ signaling which is crucial in orchestrating diverse behaviors and physiological processes including sleep and activity, feeding, growth, metabolism and reproduction. The pars intercerebralis and pars lateralis in insects represent major hubs which contain neurosecretory cells (NSC) that produce various hormones. To obtain insight into how hormonal signaling is regulated, we have characterized the synaptic connectome of NSC in the adult Drosophila brain. Identification of neurons providing inputs to multiple NSC subtypes implicates diuretic hormone 44-expressing NSC as a major coordinator of physiology and behavior. Surprisingly, despite most NSC having dendrites in the subesophageal zone (primary taste processing center), gustatory inputs to NSC are largely indirect. We also deciphered pathways via which diverse olfactory inputs are relayed to NSC. Further, our analyses revealed substantial inputs from descending neurons to NSC, suggesting that descending neurons regulate both endocrine and motor output to synchronize physiological changes with appropriate behaviors. In contrast to NSC inputs, synaptic output from NSC is sparse and mostly mediated by corazonin NSC. Therefore, we additionally determine putative paracrine interconnectivity between NSC subtypes and hormonal pathways from NSC to peripheral tissues by analyzing single-cell transcriptomic datasets. Our comprehensive characterization of the Drosophila neurosecretory network connectome provides a platform to understand complex hormonal networks and how they orchestrate animal behaviors and physiology.

Peripheral administration of a κ-opioid receptor agonist nalfurafine inactivates gonadotropin-releasing hormone pulse generator activity in goats

Neurons co-expressing kisspeptin, neurokinin B, and dynorphin A (KNDy neurons), located in the arcuate nucleus (ARC) of the hypothalamus, are indicated to be the gonadotropin-releasing hormone (GnRH) pulse generator. Dynorphin A is reported to suppress GnRH pulse generator activity. Nalfurafine is a selective agonist of the κ-opioid receptor (KOR), a receptor for dynorphin A, clinically used as an anti-pruritic drug. This study aimed to evaluate the effects of nalfurafine on GnRH pulse generator activity and luteinizing hormone (LH) pulses using female goats. Nalfurafine (0, 2, 4, 8, or 16 μg/head) was intravenously injected into ovariectomized Shiba goats. The multiple unit activity (MUA) in the ARC area was recorded, and plasma LH concentrations were measured 2 and 48 h before and after injection, respectively. The MUA volley interval during 0-2 h after injection was significantly increased in the nalfurafine 8 and 16 μg groups compared with the vehicle group. In 0-2 h after injection, the number of LH pulses was significantly decreased in the nalfurafine 8 and 16 μg groups, and the mean and baseline LH were significantly decreased in all nalfurafine-treated groups (2, 4, 8, and 16 μg) compared with the vehicle group. These results suggest that nalfurafine inhibits the activity of the GnRH pulse generator in the ARC, thus suppressing pulsatile LH secretion. Therefore, nalfurafine could be used as a reproductive inhibitor in mammals.

Capillary connections between sensory circumventricular organs and adjacent parenchyma enable local volume transmission

Among contributors to diffusible signaling are portal systems which join two capillary beds through connecting veins (Dorland 2020). Portal systems allow diffusible signals to be transported in high concentrations directly from one capillary bed to the other without dilution in the systemic circulation. Two portal systems have been identified in the brain. The first was discovered almost a century ago and connects the median eminence to the anterior pituitary gland (Popa & Fielding 1930). The second was discovered a few years ago, and links the suprachiasmatic nucleus to the organum vasculosum of the lamina terminalis, a sensory circumventricular organ (CVO) (Yao et al. 2021). Sensory CVOs bear neuronal receptors for sensing signals in the fluid milieu (McKinley et al. 2003). They line the surface of brain ventricles and bear fenestrated capillaries, thereby lacking blood brain barriers. It is not known whether the other sensory CVOs, namely the subfornical organ (SFO), and area postrema (AP) form portal neurovascular connections with nearby parenchymal tissue. This has been difficult to establish as the structures lie at the midline and protrude into the ventricular space. To preserve the integrity of the vasculature of CVOs and their adjacent neuropil, we combined iDISCO clearing and light-sheet microscopy to acquire volumetric images of blood vessels. The results indicate that there is a portal pathway linking the capillary vessels of the SFO and the posterior septal nuclei, namely the septofimbrial nucleus and the triangular nucleus of the septum. Unlike the latter arrangement, the AP and the nucleus of the solitary tract share their capillary beds. Taken together, the results reveal that all three sensory circumventricular organs bear specialized capillary connections to adjacent neuropil, providing a direct route for diffusible signals to travel from their source to their targets.

MRAP2a Binds and Modulates Activity and Localisation of Prokineticin Receptor 1 in Zebrafish

The prokineticin system plays a role in hypothalamic neurons in the control of energy homeostasis. Prokineticin receptors (PKR1 and PKR2), like other G-protein-coupled receptors (GPCRs) are involved in the regulation of energy intake and expenditure and are modulated by the accessory membrane protein 2 of the melanocortin receptor (MRAP2). The aim of this work is to characterise the interaction and regulation of the non-melanocortin receptor PKR1 by MRAP2a in zebrafish (zMRAP2a) in order to use zebrafish as a model for the development of drugs targeting accessory proteins that can alter the localisation and activity of GPCRs. To this end, we first showed that zebrafish PKR1 (zPKR1) is able to interact with both zMRAP2a and human MRAP2 (hMRAP2). This interaction occurs between the N-terminal region of zPKR1 and the C-terminal domain of zMRAP2a, which shows high sequence identity with hMRAP2 and a similar propensity for dimer formation. Moreover, we demonstrated that in Chinese hamster ovary (CHO) cells, zMRAP2a or hMRAP2 are able to modulate zPKR1 activation induced by zebrafish PK2 (zPK2) resulting in an impaired ERK and STAT3 activation.

Therapeutic potential of the linalool against cadmium-induced testicular tissue damage

Cadmium (Cd) is a heavy metal that has harmful effects and is one of the contaminants found in the environment. Cd exposure causes important pathophysiological processes, such as reproductive toxicity. Linalool (Lnl) is a monoterpene, a component of essential oils known to be produced synthetically. Additionally, Lnl has many important beneficial effects, such as anti-inflammatory and antioxidant effects. The objective of this study is to determine whether Lnl has a healing impact in opposition to testicular tissue damage due to Cd exposure. In the study, 28 male rats were divided at random into four equal groups (n = 7). No treatment was applied to the control group. CdCl2 was applied intraperitoneally to the Cd group at a dose of 3 mg/kg for the first 7 days of the trial. For the Cd + Lnl group, 3 mg/kg CdCl2 was applied intraperitoneally for the first 7 days of the trial, and 100 mg/kg/day Lnl was applied. Upon completion of all applications, the rats were sacrificed and blood samples and testicular tissue were taken. Cd exposure caused histopathological changes, oxidative stress, inflammation, and an increase in apoptotic cells in testicular tissue. However, Cd altered endocrine hormones in the hypothalamic-pituitary-gonad axis. However, Lnl application against Cd exposure was able to regulate the negativity caused by Cd in both testicular tissue and endocrine hormone levels. In conclusion, Lnl may be a potential therapeutic strategy against Cd-induced reproductive toxicity. We believe that Lnl has a high potential for further studies to determine its detailed mechanisms of action and cellular signaling pathways.

Endometriosis, Pain, and Related Psychological Disorders: Unveiling the Interplay among the Microbiome, Inflammation, and Oxidative Stress as a Common Thread

Endometriosis (EM), a chronic condition in endometrial tissue outside the uterus, affects around 10% of reproductive-age women, significantly affecting fertility. Its prevalence remains elusive due to the surgical confirmation needed for diagnosis. Manifesting with a range of symptoms, including dysmenorrhea, dyschezia, dysuria, dyspareunia, fatigue, and gastrointestinal discomfort, EM significantly impairs quality of life due to severe chronic pelvic pain (CPP). Psychological manifestations, notably depression and anxiety, frequently accompany the physical symptoms, with CPP serving as a key mediator. Pain stems from endometrial lesions, involving oxidative stress, neuroinflammation, angiogenesis, and sensitization processes. Microbial dysbiosis appears to be crucial in the inflammatory mechanisms underlying EM and associated CPP, as well as psychological symptoms. In this scenario, dietary interventions and nutritional supplements could help manage EM symptoms by targeting inflammation, oxidative stress, and the microbiome. Our manuscript starts by delving into the complex relationship between EM pain and psychological comorbidities. It subsequently addresses the emerging roles of the microbiome, inflammation, and oxidative stress as common links among these abovementioned conditions. Furthermore, the review explores how dietary and nutritional interventions may influence the composition and function of the microbiome, reduce inflammation and oxidative stress, alleviate pain, and potentially affect EM-associated psychological disorders.

Menarche-a journey into womanhood: age at menarche and health-related outcomes in East Asians

STUDY QUESTION

Are there associations of age at menarche (AAM) with health-related outcomes in East Asians?

SUMMARY ANSWER

AAM is associated with osteoporosis, Type 2 diabetes (T2D), glaucoma, and uterine fibroids, as demonstrated through observational studies, polygenic risk scores, genetic correlations, and Mendelian randomization (MR), with additional findings indicating a causal effect of BMI and T2D on earlier AAM.

WHAT IS KNOWN ALREADY

Puberty timing is linked to adult disease risk, but research predominantly focuses on European populations, with limited studies in other groups.

STUDY DESIGN, SIZE, DURATION

We performed an AAM genome-wide association study (GWAS) with 57 890 Han Taiwanese females and examined the association between AAM and 154 disease outcomes using the Taiwanese database. Additionally, we examined genetic correlations between AAM and 113 diseases and 67 phenotypes using Japanese GWAS summary statistics.

PARTICIPANTS/MATERIALS, SETTING, METHODS

We performed AAM GWAS and gene-based GWAS studies to obtain summary statistics and identify potential AAM-related genes. We applied phenotype, polygenic risk scores, and genetic correlation analyses of AAM to explore health-related outcomes, using multivariate regression and linkage disequilibrium score regression analyses. We also explored potential bidirectional causal relationships between AAM and related outcomes through univariable and multivariable MR analyses.

MAIN RESULTS AND THE ROLE OF CHANCE

Fifteen lead single-nucleotide polymorphisms and 24 distinct genes were associated with AAM in Taiwan. AAM was genetically associated with later menarche and menopause, greater height, increased osteoporosis risk, but lower BMI, and reduced risks of T2D, glaucoma, and uterine fibroids in East Asians. Bidirectional MR analyses indicated that higher BMI/T2D causally leads to earlier AAM.

LIMITATIONS, REASONS FOR CAUTION

Our findings were specific to Han Taiwanese individuals, with genetic correlation analyses conducted in East Asians. Further research in other ethnic groups is necessary.

WIDER IMPLICATIONS OF THE FINDINGS

Our study provides insights into the genetic architecture of AAM and its health-related outcomes in East Asians, highlighting causal links between BMI/T2D and earlier AAM, which may suggest potential prevention strategies for early puberty.

STUDY FUNDING/COMPETING INTEREST(S)

The work was supported by China Medical University, Taiwan (CMU110-S-17, CMU110-S-24, CMU110-MF-49, CMU111-SR-158, CMU111-MF-105, CMU111-MF-21, CMU111-S-35, CMU112-SR-30, and CMU112-MF-101), the China Medical University Hospital, Taiwan (DMR-111-062, DMR-111-153, DMR-112-042, DMR-113-038, and DMR-113-103), and the Ministry of Science and Technology, Taiwan (MOST 111-2314-B-039-063-MY3, MOST 111-2314-B-039-064-MY3, MOST 111-2410-H-039-002-MY3, and NSTC 112-2813-C-039-036-B). The funders had no influence on the data collection, analyses, or conclusions of the study. No conflict of interests to declare.

TRIAL REGISTRATION NUMBER

N/A.

Mechanisms of Male Reproductive Sterility Triggered by Dysbiosis of Intestinal Microorganisms

The intestinal microbiota, comprised of bacteria, archaea, and phages, inhabits the gastrointestinal tract of the organism. Male reproductive sterility is currently a prominent topic in medical research. Increasing research suggests that gut microbiota dysbiosis can result in various reproductive health problems. This article specifically investigates the impact of gut microbiota dysbiosis on male reproductive infertility development. Gut microbiota imbalances can disrupt the immune system and immune cell metabolism, affecting testicular growth and sperm production. This dysfunction can compromise the levels of hormones produced and secreted by the endocrine glands, affecting male reproductive health. Furthermore, imbalance of the gut microbiota can disrupt the gut-brain-reproductive axis, resulting in male reproductive infertility. This article explores how the imbalance of the gut microbiota impacts male reproductive infertility through immune regulation, endocrine regulation, and interactions of the gut-brain-reproductive axis, concluding with recommendations for prevention and treatment.

Foxp2 deficiency impairs reproduction by modulating the hypothalamic-pituitary-gonadal axis in zebrafish†

FOXP2 was initially characterized as a transcription factor linked to speech and language disorders. Single-cell RNA sequencing reveals that Foxp2 is enriched in the gonadotrope cluster of the pituitary gland and colocalized with the hormones LHB and FSHB in chickens and mice, implying that FOXP2 might be associated with reproduction in vertebrates. Herein, we investigated the roles of foxp2 in reproduction in a Foxp2-deficient zebrafish model. The results indicated that the loss of Foxp2 inhibits courtship behavior in adult male zebrafish. Notably, Foxp2 deficiency disrupts gonad development, leading to retardation of follicle development and a decrease in oocytes in females at the full-growth stage, among other phenotypes. The transcriptome analysis (RNA-seq) also revealed that differentially expressed genes clustered into the estrogen signaling and ovarian steroidogenesis-related signaling pathways. In addition, we found that Foxp2 deficiency could modulate the hypothalamic-pituitary-gonadal axis, especially the regulation of lhb and fshb expression, in zebrafish. In contrast, the injection of human chorionic gonadotropin, a specific LH agonist, partially rescues Foxp2-impaired reproduction in zebrafish, suggesting that Foxp2 plays an important role in the regulation of reproduction via the hypothalamic-pituitary-gonadal axis in zebrafish. Thus, our findings reveal a new role for Foxp2 in the regulation of reproduction in vertebrates.

The effects of inhaled pollutants on reproduction in marginalized communities: a contemporary review

Important differences in health that are closely linked with social disadvantage exist within and between countries. According to the World Health Organization, life expectancy and good health continue to increase in many parts of the world, but fail to improve in other parts of the world, indicating that differences in life expectancy and health arise due to the circumstances in which people grow, live, work, and age, and the systems put in place to deal with illness. Marginalized communities experience higher rates of certain diseases and more deaths compared to the general population, indicating a profound disparity in health status. Although several factors place marginalized communities at high risk for poor health outcomes, one important factor is exposure to air pollutants. Marginalized communities and minorities are exposed to higher levels of air pollutants than the majority population. Interestingly, a link exists between air pollutant exposure and adverse reproductive outcomes, suggesting that marginalized communities may have increased reproductive disorders due to increased exposure to air pollutants compared to the general population. This review summarizes different studies showing that marginalized communities have higher exposure to air pollutants, the types of air pollutants present in our environment, and the associations between air pollution and adverse reproductive outcomes, focusing on marginalized communities.

Etiology of Male Infertility: an Update

Spermatogenesis is a complex process of germ cell division and differentiation that involves extensive cross-talk between the developing germ cells and the somatic testicular cells. Defective endocrine signaling and/or intrinsic defects within the testes can adversely affect spermatogenic progression, leading to subfertility/infertility. In recent years, male infertility has been recognized as a global public health concern, and research over the last few decades has elucidated the complex etiology of male infertility. Congenital reproductive abnormalities, genetic mutations, and endocrine/metabolic dysfunction have been demonstrated to be involved in infertility/subfertility in males. Furthermore, acquired factors like exposure to environmental toxicants and lifestyle-related disorders such as illicit use of psychoactive drugs have been shown to adversely affect spermatogenesis. Despite the large body of available scientific literature on the etiology of male infertility, a substantial proportion of infertility cases are idiopathic in nature, with no known cause. The inability to treat such idiopathic cases stems from poor knowledge about the complex regulation of spermatogenesis. Emerging scientific evidence indicates that defective functioning of testicular Sertoli cells (Sc) may be an underlying cause of infertility/subfertility in males. Sc plays an indispensable role in regulating spermatogenesis, and impaired functional maturation of Sc has been shown to affect fertility in animal models as well as humans, suggesting abnormal Sc as a potential underlying cause of reproductive insufficiency/failure in such cases of unexplained infertility. This review summarizes the major causes of infertility/subfertility in males, with an emphasis on infertility due to dysregulated Sc function.

Neurotensin agonist PD149163 modulates lipopolysaccharide induced inflammation and oxidative stress in the female reproductive system of mice

Inflammation-mediated reproductive health problems in females have become an emerging concern. The present investigation was aimed to elucidate the efficacy of the PD149163, agonist of the type I neurotensin receptor, in preventing/ameliorating the lipopolysaccharide (LPS) induced inflammation of the female reproductive system of the mice. Female Swiss Albino Mice (8 weeks old) were maintained in three groups (6/group): Group I as Control, Group II and Group III were exposed to intraperitoneal (i.p) LPS (1 mg/kg bw) for 5 days followed by treatment with PD149163 (100 μg/kg BW i.p.) to Group III (LPS + PD) for 28 days. After termination of the experiment on 29th day, plasma levels of inflammatory cytokines, LH, FSH, estradiol, corticosterone, oxidative stress effects in the ovary and histopathological study of the ovary and uterine horn were done. LPS-induced inflammation of the ovary and uterine horn was ameliorated/prevented by PD149163 as reflected in the reduced histopathological scores, significant elevation of the plasma anti-inflammatory cytokine IL-10 and decrease of the pro inflammatory cytokines TNF-α and IL-6. Significant decrease of lipid peroxide, increase of antioxidant defense enzymes, Superoxide dismutase and Catalase in the ovary indicated reduction of oxidative stress. The plasma levels of the reproduction related hormones and corticosterone were restored. PD149163 acts as an anti-inflammatory and anti-oxidative agent in modulation of inflammation in the female reproductive system (ovary & uterine horn). These findings suggest that the therapeutic potential of the analogs of neurotensin including PD149163 should be explored for the treatment of the female reproductive health issues.

Aspartame Intake Delayed Puberty Onset in Female Offspring Rats and Girls

SCOPE

The disturbance of the hypothalamic-pituitary-gonadal (HPG) axis, gut microbiota (GM) community, and short-chain fatty acids (SCFAs) is a triggering factor for pubertal onset. The study investigates the effects of the long-term intake of aspartame on puberty and GM in animals and humans.

METHODS AND RESULTS

Aspartame-fed female offspring rats result in vaginal opening time prolongation, serum estrogen reduction, and serum luteinizing hormone elevation. , 60 mg kg-1 aspartame treatment decreases the mRNA levels of gonadotropin-releasing hormone (GnRH), Kiss1, and G protein-coupled receptor 54 (GPR54), increases the mRNA level of RFamide-related peptide-3 (RFRP-3), and decreases the expression of GnRH neurons in the hypothalamus. Significant differences in relative bacterial abundance at the genus levels and decreased fecal SCFA levels are noted by 60 mg kg-1 aspartame treatment. Among which, Escherichia-Shigella is negatively correlated with several SCFAs. In girls, high-dose aspartame consumption decreases the risk of precocious puberty.

CONCLUSIONS

Aspartame reduces the chance of puberty occurring earlier than usual in female offspring and girls. Particularly, 60 mg kg-1 aspartame-fed female offspring delays pubertal onset through the dysregulation of HPG axis and GM composition by inhibiting the Kiss1/GPR54 system and inducing the RFRP-3. An acceptable dose of aspartame should be recommended during childhood.

Maternal Age at Menarche Genes Determines Fetal Growth Restriction Risk

We aimed to explore the potential link of maternal age at menarche (mAAM) gene polymorphisms with risk of the fetal growth restriction (FGR). This case (FGR)-control (FGR free) study included 904 women (273 FGR and 631 control) in the third trimester of gestation examined/treated in the Departments of Obstetrics. For single nucleotide polymorphism (SNP) multiplex genotyping, 50 candidate loci of mAAM were chosen. The relationship of mAAM SNPs and FGR was appreciated by regression procedures (logistic/model-based multifactor dimensionality reduction [MB-MDR]) with subsequent in silico assessment of the assumed functionality pithy of FGR-related loci. Three mAAM-appertain loci were FGR-linked to genes such as KISS1 (rs7538038) (effect allele G-odds ratio (OR)allelic = 0.63/pperm = 0.0003; ORadditive = 0.61/pperm = 0.001; ORdominant = 0.56/pperm = 0.001), NKX2-1 (rs999460) (effect allele A-ORallelic = 1.37/pperm = 0.003; ORadditive = 1.45/pperm = 0.002; ORrecessive = 2.41/pperm = 0.0002), GPRC5B (rs12444979) (effect allele T-ORallelic = 1.67/pperm = 0.0003; ORdominant = 1.59/pperm = 0.011; ORadditive = 1.56/pperm = 0.009). The haplotype ACA FSHB gene (rs555621*rs11031010*rs1782507) was FRG-correlated (OR = 0.71/pperm = 0.05). Ten FGR-implicated interworking models were founded for 13 SNPs (pperm ≤ 0.001). The rs999460 NKX2-1 and rs12444979 GPRC5B interplays significantly influenced the FGR risk (these SNPs were present in 50% of models). FGR-related mAAM-appertain 15 polymorphic variants and 350 linked SNPs were functionally momentous in relation to 39 genes participating in the regulation of hormone levels, the ovulation cycle process, male gonad development and vitamin D metabolism. Thus, this study showed, for the first time, that the mAAM-appertain genes determine FGR risk.

Analysis of the association between testosterone and cardiovascular disease potential risk factor apolipoprotein B in adult males without cancer: national health and nutrition examination survey 2011-2016

Background

Over the years, there has been extensive exploration of the association between testosterone and lipid profiles, yet the precise mechanisms underlying their interaction remain incompletely elucidated. Similarly, there is a dearth of research on the correlation between serum apolipoprotein B (apoB) and serum total testosterone (TT), particularly within specific populations.

Methods

We conducted a cross-sectional study to assess the relationship between serum TT concentration and serum apoB concentration. Using the National Health and Nutrition Examination Survey (NHANES) from 2011 to 2016, we employed weighted generalized linear models, weighted univariate, weighted multivariate analysis, and smooth curve fitting to assist in exploring the relationship between serum TT and apoB. Serum apoB concentration served as the independent variable, and serum TT concentration as the dependent variable. ApoB was divided into four quartiles-Q1 (<0.7g/L, N=691), Q2 (≥0.7g/L to <0.9g/L, N=710), Q3 (≥0.9g/L to <1.1g/L, N=696), and Q4 (≥1.1g/L, N=708)-thereby further solidifying the stable association between the two. Additionally, the application of smooth curve fitting will contribute to a more detailed elucidation of the specific relationship between serum TT concentration and serum apoB concentration under different factors (Drinking, Smoke, Diabetes, Hypertension, and High cholesterol level.).

Results

The results indicate a negative correlation between serum TT concentration and apoB concentration (β=-113.4; 95% CI: -146.6, -80.2; P<0.001). After adjusting for confounding variables, the negative correlation between apoB concentration and TT concentration remains significant (β=-61.0; 95% CI: -116.7, -5.2; P=0.040). When apoB concentration was converted from a continuous variable to a categorical variable (quartiles: Q1<0.7g/L; Q2:≥0.7g/L to<0.9g/L; Q3:≥0.9g/L to <1.1g/L; Q4: ≥1.1g/L), TT level of participants in the highest quartile (≥1.1g/L) was -47.2 pg/mL (95% CI: -91.2, -3.3; P=0.045) lower than that in the lowest quartile (<0.7g/L). The smooth curve fitting diagram revealed differences in the relationship between TT concentration and apoB among individuals with different cardiovascular disease (CVD) risk factors.

Conclusions

This study elucidates a robust inverse correlation between serum TT concentration and apoB concentration, maintaining statistical significance even upon adjustment for confounding factors. These findings present a promising avenue for addressing the prevention and treatment of low testosterone and CVD.

Causal Relationship Between Sleep Traits and Hypothalamic-Pituitary-Target Gland Axis Function: A Mendelian Randomization Study

Background

In recent years, multiple observational studies have confirmed the association between sleep traits and various human physiopathological states. However, the causal relationship between sleep traits and hypothalamic-pituitary-target gland axis (HPTGA) function remains unknown.

Methods

We obtained summary statistics on sleep traits (insomnia, chronotype, and sleep duration (long and short)) from the UK Biobank database. Data related to the HPTGA functions were obtained from the publicly available database. Subsequently, a two-sample Mendelian randomization (MR) analysis was performed to investigate the causal relationship between different sleep traits and the HPTGA function. Reverse MR analysis was conducted to examine the direction of causality.

Results

The MR analysis results suggested that chronotype is associated with decreased levels of six hormones in HPTGA. Sleep duration was causally associated with decreased levels of free thyroxine and progesterone. Both long and short sleep durations are detrimental to the secretion of prolactin-releasing peptide, somatostatin, and plasma cortisol, while short sleep duration can promote progesterone secretion. After gender stratification, we found that female reproductive function is more susceptible to the influence of unfavorable sleep traits.

Conclusion

Our MR analysis indicated a significant causal association between chronotype and suppressed gonadal function in healthy adult humans, with no apparent gender-specific effect. Extreme sleep durations were also found to be detrimental to the maintenance of normal HPTGA secretion function. Compared to males, gonadal function in the female cohort is more susceptible to extreme sleep habits. Subsequent observational studies are urgently needed to confirm the underlying mechanisms.

Epigenetics of inflammation in hypothalamus pituitary gonadal and neuroendocrine disorders

The hormone producing hypothalamus, pituitary and gonadal are arranged in hierarchy to form the hypothalamic-pituitary-gonadal axis (HPG axis). The axis is neuroendocrine in nature and releases hormones in response to the inputs from nervous systems. The axis maintains homeostasis and ensures smooth body functions, particularly those related to growth and reproduction. A deregulated HPG axis, such as observed under inflammation and other conditions, is therefore associated with several disorders such as polycystic ovary syndrome, functional hypothalamic amenorrhea etc. Several factors, both genetic as well as environmental, in addition to aging, obesity etc. affect HPG axis with resulting effects on puberty, sexual maturation and reproductive health. More research is now indicative of a role of epigenetics in mediating these HPG-affecting factors. Hypothalamus-secreted gonadotropin-releasing hormone is important for eventual release of sex hormones and it is subjected to several neuronal and epigenetic regulations. Gene promoter methylation as well as histone methylations and acetylations form the backbone of epigenetic regulation of HPG-axis, as the incoming reports suggest. Epigenetic events also mediate several feedback mechanisms within HPG axis and between HPG axis and the central nervous system. In addition, data is emerging for a role of non-coding RNAs, particularly the miRNAs, in regulation and normal functioning of HPG axis. Thus, the epigenetic interactions need better understanding to understand the functioning and regulation of HPG axis.

Metabolic hormones are integral regulators of female reproductive health and function

The female reproductive system is strongly influenced by nutrition and energy balance. It is well known that food restriction or energy depletion can induce suppression of reproductive processes, while overnutrition is associated with reproductive dysfunction. However, the intricate mechanisms through which nutritional inputs and metabolic health are integrated into the coordination of reproduction are still being defined. In this review, we describe evidence for essential contributions by hormones that are responsive to food intake or fuel stores. Key metabolic hormones-including insulin, the incretins (glucose-dependent insulinotropic polypeptide and glucagon-like peptide-1), growth hormone, ghrelin, leptin, and adiponectin-signal throughout the hypothalamic-pituitary-gonadal axis to support or suppress reproduction. We synthesize current knowledge on how these multifaceted hormones interact with the brain, pituitary, and ovaries to regulate functioning of the female reproductive system, incorporating in vitro and in vivo data from animal models and humans. Metabolic hormones are involved in orchestrating reproductive processes in healthy states, but some also play a significant role in the pathophysiology or treatment strategies of female reproductive disorders. Further understanding of the complex interrelationships between metabolic health and female reproductive function has important implications for improving women's health overall.

Reproductive Profile of Neuronal Androgen Receptor Knockout Female Mice With a Low Dose of DHT

Hyperandrogenism and polycystic ovarian syndrome result from the imbalance or increase of androgen levels in females. Androgen receptor (AR) mediates the effects of androgens, and this study examines whether neuronal AR plays a role in reproduction under normal and increased androgen conditions in female mice. The neuron-specific AR knockout (KO) mouse (SynARKO) was generated from a female mouse (synapsin promoter driven Cre) and a male mouse (Ar fl/y). Puberty onset and the levels of reproductive hormones such as LH, FSH, testosterone, and estradiol were comparable between the control and the SynARKO mice. There were no differences in cyclicity and fertility between the control and SynARKO mice, with similar impairment in both groups on DHT treatment. Neuronal AR KO, as in this SynARKO mouse model, did not alleviate the infertility associated with DHT treatment. These studies suggest that neuronal AR KO neither altered reproductive function under physiological androgen levels, nor restored fertility under hyperandrogenic conditions.

Advances in steroid research from the pioneering neurosteroid concept to metabolomics: New insights into pregnenolone function

Advances in neuroendocrinology have led to major discoveries since the 19th century, identifying adaptive loops for maintaining homeostasis. One of the most remarkable discoveries was the concept of neurosteroids, according to which the brain is not only a target but also a source of steroid production. The identification of new membrane steroid targets now underpins the neuromodulatory effects of neurosteroids such as pregnenolone, which is involved in functions mediated by the GPCR CB1 receptor. Structural analysis of steroids is a key feature of their interactions with the phospholipid membrane, receptors and resulting activity. Therefore, mass spectrometry-based methods have been developed to elucidate the metabolic pathways of steroids, the ultimate approach being metabolomics, which allows the identification of a large number of metabolites in a single sample. This approach should enable us to make progress in understanding the role of neurosteroids in the functioning of physiological and pathological processes.

Pseudorabies virus inhibits progesterone-induced inactivation of TRPML1 to facilitate viral entry

Viral infection is a significant risk factor for fertility issues. Here, we demonstrated that infection by neurotropic alphaherpesviruses, such as pseudorabies virus (PRV), could impair female fertility by disrupting the hypothalamus-pituitary-ovary axis (HPOA), reducing progesterone (P4) levels, and consequently lowering pregnancy rates. Our study revealed that PRV exploited the transient receptor potential mucolipin 1 (TRPML1) and its lipid activator, phosphatidylinositol 3,5-bisphosphate (PI(3,5)P2), to facilitate viral entry through lysosomal cholesterol and Ca2+. P4 antagonized this process by inducing lysosomal storage disorders and promoting the proteasomal degradation of TRPML1 via murine double minute 2 (MDM2)-mediated polyubiquitination. Overall, the study identifies a novel mechanism by which PRV hijacks the lysosomal pathway to evade P4-mediated antiviral defense and impair female fertility. This mechanism may be common among alphaherpesviruses and could contribute significantly to their impact on female reproductive health, providing new insights for the development of antiviral therapies.

Developmental programming of production and reproduction in dairy cows: II. Association of gestational stage of maternal exposure to heat stress with offspring's birth weight, milk yield, reproductive performance and AMH concentration during the first lactation period

Although the negative effect of maternal exposure to heat stress on production and reproduction of offspring has been reported, there are some discrepancies among various studies about which gestational stage is more critical in this regard. Therefore, the present research was conducted to identify during which stage(s) of pregnancy maternal exposure to heat stress would lead to more dramatic decrease in productive and reproductive performance of offspring. To this end, offspring were classified based on the gestational stage they were in utero exposed to heat stress into four categories, including heat stress exposure (HSE) during only the first trimester of gestation (HSE1), HSE during the first and second trimester of gestation (HSE2), HSE during the second and third trimester of gestation (HSE3) and HSE during only the third trimester of gestation (HSE4). In study I, data of birth weight, milk yield and reproductive variables of 11,788 offspring and data of the month they were conceived were retrieved. In study II, blood samples (n = 521) were collected from offspring in various categories of HSE for measurement of serum AMH. Offspring in HSE1 and HSE2 categories were heavier than offspring in HSE3 and HSE4 categories (P < 0.0001). Offspring in HSE1 and HSE3 categories had the lowest and highest milk production, respectively (P < 0.05). First service conception rate was the greatest and worst in HSE1 and HSE4 categories, respectively (P < 0.05). Service per conception and calving to conception interval were greater in HSE2 than HSE4 category (P < 0.05). Concentration of AMH was lower in HSE1 than HSE4 category (P < 0.05). In conclusion, the present study indicated that the early stage of gestation could be a more critical period for the negative impact of in utero heat stress on developmental programming of milk production and ovarian reserves. Yet an evident temporal pattern for the adverse effect of maternal heat stress on developmental programming of reproductive performance in offspring was not found.

Therapeutic Potential of Targeting Prokineticin Receptors in Diseases

The prokineticins (PKs) were discovered approximately 20 years ago as small peptides inducing gut contractility. Today, they are established as angiogenic, anorectic, and proinflammatory cytokines, chemokines, hormones, and neuropeptides involved in variety of physiologic and pathophysiological pathways. Their altered expression or mutations implicated in several diseases make them a potential biomarker. Their G-protein coupled receptors, PKR1 and PKR2, have divergent roles that can be therapeutic target for treatment of cardiovascular, metabolic, and neural diseases as well as pain and cancer. This article reviews and summarizes our current knowledge of PK family functions from development of heart and brain to regulation of homeostasis in health and diseases. Finally, the review summarizes the established roles of the endogenous peptides, synthetic peptides and the selective ligands of PKR1 and PKR2, and nonpeptide orthostatic and allosteric modulator of the receptors in preclinical disease models. The present review emphasizes the ambiguous aspects and gaps in our knowledge of functions of PKR ligands and elucidates future perspectives for PK research. SIGNIFICANCE STATEMENT: This review provides an in-depth view of the prokineticin family and PK receptors that can be active without their endogenous ligand and exhibits "constitutive" activity in diseases. Their non- peptide ligands display promising effects in several preclinical disease models. PKs can be the diagnostic biomarker of several diseases. A thorough understanding of the role of prokineticin family and their receptor types in health and diseases is critical to develop novel therapeutic strategies with safety concerns.

Selective Modulation of the Keratoconic Stromal Microenvironment by FSH and LH

Keratoconus (KC) affects the corneal structure, with thinning and bulging outward into a conelike shape. Irregular astigmatism and decreased visual acuity appear during puberty and progress into the mid-30s, with unpredictable disease severity. The cause of KC is recognized as multifactorial, but remains poorly understood. Hormone imbalances are a significant modulator of the onset of KC. This study sought to investigate the role of gonadotropins, follicle-stimulating hormone (FSH), and luteinizing hormone (LH) in KC, using a three-dimensional, self-assembled matrix in vitro model. Healthy corneal fibroblasts and human KC cells in the corneal stroma were isolated, cultured, and stimulated with stable vitamin C to promote extracellular matrix assembly. Cultures were further stimulated with 2.5 or 10 mIU/mL FSH and 5 or 35 mIU/mL LH. Samples were evaluated for cell proliferation and morphology via BrdU assay and imaging; protein expression was assessed via Western blot analysis. Proliferation was significantly greater in human KC cells compared to healthy corneal fibroblasts with LH stimulation, but no changes were found with FSH stimulation. Additionally, in sex hormone receptors, fibrotic markers, proteoglycans, and members of the gonadotropin signaling pathway were significantly changed, largely driven by exogenous LH. The impact of exogenous FSH/LH in the KC stromal microenvironment was demonstrated. These results highlight the need to further examine the role of FSH/LH in KC and in human corneal homeostasis.

Overactivation of GnRH neurons is sufficient to trigger polycystic ovary syndrome-like traits in female mice

BACKGROUND

Polycystic ovary syndrome (PCOS) is the most common endocrine disorder leading to anovulatory infertility. Abnormalities in the central neuroendocrine system governed by gonadotropin-releasing hormone (GnRH) neurons might be related to ovarian dysfunction in PCOS, although the link in this disordered brain-to-ovary communication remains unclear. Here, we manipulated GnRH neurons using chemogenetics in adult female mice to unveil whether chronic overaction of these neurons would trigger PCOS-like hormonal and reproductive impairments.

METHODS

We used adult Gnrh1cre female mice to selectively target and express the designer receptors exclusively activated by designer drugs (DREADD)-based chemogenetic tool hM3D(Gq) in hypophysiotropic GnRH neurons. Chronic chemogenetic activation protocol was carried out with clozapine N-oxide (CNO) i.p. injections every 48 h over a month. We evaluated the reproductive and hormonal profile before, during, and two months after chemogenetic manipulations.

FINDINGS

We discovered that the overactivation of GnRH neurons was sufficient to disrupt reproductive cycles, promote hyperandrogenism, and induce ovarian dysfunction. These PCOS features were detected with a long-lasting neuroendocrine dysfunction through abnormally high luteinizing hormone (LH) pulse secretion. Additionally, the GnRH-R blockade prevented the establishment of long-term neuroendocrine dysfunction and androgen excess in these animals.

INTERPRETATION

Taken together, our results show that hyperactivity of hypothalamic GnRH neurons is a major driver of reproductive and hormonal impairments in PCOS and suggest that antagonizing the aberrant GnRH signaling could be an efficient therapeutic venue for the treatment of PCOS.

FUNDING

European Research Council (ERC) under the European Union's Horizon 2020 research and innovation program (grant agreement n◦ 725149).

A Scientometric Evaluation of COVID-19 and Male Reproductive Research

The COVID-19 pandemic due to the SARS-CoV-2 coronavirus showed acute and prolonged effects on human health. In addition, over the past four years, there has been a tremendous surge in COVID-19-related scientific publications, as shown by bibliometric and scientometric studies. However, such analysis of the scientific literature is lacking in the area of male reproduction. The current scientometric study analyzes publication characteristics of articles related to male reproduction and COVID-19 infection. We used the Scopus database to analyze scientometric data (the number of publications, journals, countries, type of documents, and subject area) related to COVID-19 and male reproductive research. Our literature search identified 345 articles related to COVID-19 and male reproductive research. Most of the articles were published in the USA (n = 72), Italy (n = 55), and China (n = 51). Such research was mainly focused around medicine (57.1%), followed by biochemistry, genetics, and molecular biology (25.7%). Also, in the area of male reproduction, only 37.1% (n = 128) of the articles contributed towards original research, whereas 52.8% (n = 182) were review articles and editorials focusing more on sexual dysfunction than infertility. Such a small number of studies published on COVID-19-related effects on male reproduction warrants a significant increase in research, which is required to decipher the mechanism(s) underlying SARS-CoV-2 infection-associated impairment of male reproductive function.

Developmental programming of production and reproduction in dairy cows: I. Association of maternal parity with offspring's birth weight, milk yield, reproductive performance and AMH concentration during the first lactation period

Multiparous dams have been reported to produce offspring with greater fertility and higher AMH concentration, as a marker of ovarian reserves, as compared with nulliparous and primiparous dams. Yet it has remained to be addressed whether this phenomenon can still be true for old multiparous cows which might experience some geriatric changes in their reproductive system. Therefore, the present study was conducted to evaluate the productive and reproductive performance of offspring with different maternal parity. To this end, offspring were classified based on their maternal parities into four categories, including offspring of nulliparous (no previous parity), primiparous (one previous parity), young multiparous (two to six previous parities) and old multiparous (seven or more previous parities) dams. In study I, data of birth weight, milk yield and reproductive variables of 11,788 offspring and data of their maternal parity were retrieved. In study II, blood samples (n = 521) were collected from offspring with various maternal parity for measurement of serum AMH. Birth weight was the lowest in the offspring of nulliparous dams (P < 0.0001) and it was lower in offspring of primiparous and old multiparous dams than offspring of young multiparous dams (P < 0.05). Milk production was the lowest in offspring of old multiparous dams (P < 0.01), and it was lower in offspring of young multiparous dams than offspring of nulliparous and primiparous dams (P < 0.0001). Offspring of old multiparous dams had greater first service conception rate, less services per conception and shorter calving to conception interval than offspring of nulliparous, primiparous and young multiparous dams (P < 0.05). Furthermore, AMH concentration was higher in offspring of old multiparous dams than offspring of nulliparous and primiparous dams (P < 0.05). In conclusion, the present study revealed greater milk production in offspring resulting from dams with lower parity, probably due to the genetic selection for improvement of milk production in dairy cows which imparts the younger generations greater genetic merits for milk production. Reproductive performance, however, was greater in offspring born to dams with higher parity, particularly those born to old multiparous dams, and this phenomenon might be related to their lower milk production and higher AMH concentration.

Neural substrates underlying rhythmic coupling of female reproductive and thermoregulatory circuits

Coordinated fluctuations in female reproductive physiology and thermoregulatory output have been reported for over a century. These changes occur rhythmically at the hourly (ultradian), daily (circadian), and multi-day (ovulatory) timescales, are critical for reproductive function, and have led to the use of temperature patterns as a proxy for female reproductive state. The mechanisms underlying coupling between reproductive and thermoregulatory systems are not fully established, hindering the expansion of inferences that body temperature can provide about female reproductive status. At present, numerous digital tools rely on temperature to infer the timing of ovulation and additional applications (e.g., monitoring ovulatory irregularities and progression of puberty, pregnancy, and menopause are developed based on the assumption that reproductive-thermoregulatory coupling occurs across timescales and life stages. However, without clear understanding of the mechanisms and degree of coupling among the neural substrates regulating temperature and the reproductive axis, whether such approaches will bear fruit in particular domains is uncertain. In this overview, we present evidence supporting broad coupling among the central circuits governing reproduction, thermoregulation, and broader systemic physiology, focusing on timing at ultradian frequencies. Future work characterizing the dynamics of reproductive-thermoregulatory coupling across the lifespan, and of conditions that may decouple these circuits (e.g., circadian disruption, metabolic disease) and compromise female reproductive health, will aid in the development of strategies for early detection of reproductive irregularities and monitoring the efficacy of fertility treatments.

Effect of Hypoglycemic Drugs on Kisspeptin Expression in the Hypothalamic Arcuate Nucleus of PCOS Rats

Background

To investigate the change in hypothalamic kisspeptin-1 (Kiss1) expression during the development of polycystic ovary syndrome (PCOS) and hypoglycemic drug intervention.

Methods

Letrozole lavage was used to construct a polycystic ovary rat model. After successful modeling, we treated PCOS rats with metformin, pioglitazone, and acarbose, and we then observed changes in weight, estrus, glucose tolerance, insulin resistance, sex hormones, and hypothalamic kiss1 expression.

Results

PCOS rats exhibited increased body weight, abnormal estrous cycle, impaired glucose tolerance, insulin resistance, increased testosterone level, increased luteinizing hormone level, and increased Kiss1 expression in the hypothalamus. However, intervention with metformin, pioglitazone, and acarbose improved the reproductive and metabolic disorders as well as reduced hypothalamic Kiss1 expression.

Conclusion

The expression of hypothalamic Kiss1 may play an important role in the pathogenesis of PCOS. Metformin, pioglitazone, and acarbose may reduce the expression of hypothalamic Kiss1 by improving insulin resistance, thereby improving reproductive and metabolic disorders in PCOS rats.

The role of GnRH in Tibetan male sheep and goat reproduction

The hypothalamic-pituitary-gonadal (HPG) axis connects the hypothalamus, pituitary gland, and gonads. The regulation of reproductive processes includes integrating various factors from structural functions and environmental conditions in the HPG axis, with the outcome indication of these processes being the pulsatile secretion of gonadotropin-releasing hormone (GnRH) from the hypothalamus. These factors include feed consumption and nutritional condition, sex steroids, season/photoperiod, pheromones, age, and stress. GnRH pulsatile secretion affects the pattern of gonadotropin secretion of follicle-stimulating hormone (FSH) and luteinizing hormone (LH), which then regulates both endocrine function and gamete maturation in the gonads. This regulates gonadotropins and testosterone (T) production. There is evidence that in males, GnRH participates in a variety of host behavioural and physiological processes such as the release of reproductive hormones, progression of spermatogenesis and sperm function, aggressive behaviour, and physiological metabolism. GnRH activates receptors expressed on Leydig cells and Sertoli cells, respectively to stimulate T secretion and spermatogenesis in the testis. Photoperiod affects the reproductive system of the hypothalamic-pituitary axis via rhythmic diurnal melatonin secretion. Increased release of melatonin promotes sexual activity, GnRH production, LH stimulation, and T production. This induces testicular functions, spermatogenesis, and puberty. GnRH reduces the release of LH by the pituitary through the cascade effect and decreases plasma concentration of T. Gut microbiota maintain sex steroid homeostasis and may induce reduction in reproduction productivity. Recently, findings of kisspeptin-neurokinin-dynorphin neuronal network in the brain have resulted in fast advances in how GnRH secretion is controlled. Emerging studies have also indicated that other neuropeptide analogues could be used in control reproduction procedures in various goat and sheep breeds. The Tibetan male sheep and goats reproduce on a seasonal basis and have high reproductive performance. This is a review for the role of GnRH in Tibetan male sheep and goats reproduction. This is intended to enhance reproductive knowledge for understanding the key roles of GnRH relating to male reproductive efficiency of Tibetan sheep or goats.

DNA Damage Repair Pathways in Prostate Cancer: A Narrative Review of Molecular Mechanisms, Emerging Biomarkers and Therapeutic Targets in Precision Oncology

Prostate cancer (PCa) has a distinct molecular signature, including characteristic chromosomal translocations, gene deletions and defective DNA damage repair mechanisms. One crucial pathway involved is homologous recombination deficiency (HRD) and it is found in almost 20% of metastatic castrate-resistant PCa (mCRPC). Inherited/germline mutations are associated with a hereditary predisposition to early PCa development and aggressive behavior. BRCA2, ATM and CHECK2 are the most frequently HRD-mutated genes. BRCA2-mutated tumors have unfavorable clinical and pathological characteristics, such as intraductal carcinoma. PARP inhibitors, due to the induction of synthetic lethality, have been therapeutically approved for mCRPC with HRD alterations. Mutations are detected in metastatic tissue, while a liquid biopsy is utilized during follow-up, recognizing acquired resistance mechanisms. The mismatch repair (MMR) pathway is another DNA repair mechanism implicated in carcinogenesis, although only 5% of metastatic PCa is affected. It is associated with aggressive disease. PD-1 inhibitors have been used in MMR-deficient tumors; thus, the MMR status should be tested in all metastatic PCa cases. A surrogate marker of defective DNA repair mechanisms is the tumor mutational burden. PDL-1 expression and intratumoral lymphocytes have ambivalent predictive value. Few experimental molecules have been so far proposed as potential biomarkers. Future research may further elucidate the role of DNA damage pathways in PCa, revealing new therapeutic targets and predictive biomarkers.

Maternal Age at Menarche Gene Polymorphisms Are Associated with Offspring Birth Weight

In this study, the association between maternal age at menarche (AAM)-related polymorphisms and offspring birth weight (BW) was studied. The work was performed on a sample of 716 pregnant women and their newborns. All pregnant women underwent genotyping of 50 SNPs of AAM candidate genes. Regression methods (linear and Model-Based Multifactor Dimensionality Reduction (MB-MDR)) with permutation procedures (the indicator p_perm was calculated) were used to identify the correlation between SNPs and newborn weight (transformed BW values were analyzed) and in silico bioinformatic examination was applied to assess the intended functionality of BW-associated loci. Four AAM-related genetic variants were BW-associated including genes such as POMC (rs7589318) (β_additive = 0.202/p_perm = 0.015), KDM3B (rs757647) (β_recessive = 0.323/p_perm = 0.005), INHBA (rs1079866) (β_additive = 0.110/p_perm = 0.014) and NKX2-1 (rs999460) (β_recessive = -0.176/p_perm = 0.015). Ten BW-significant models of interSNPs interactions (p_perm ≤ 0.001) were identified for 20 polymorphisms. SNPs rs7538038 KISS1, rs713586 RBJ, rs12324955 FTO and rs713586 RBJ-rs12324955 FTO two-locus interaction were included in the largest number of BW-associated models (30% models each). BW-associated AAM-linked 22 SNPs and 350 proxy loci were functionally related to 49 genes relevant to pathways such as the hormone biosynthesis/process and female/male gonad development. In conclusion, maternal AMM-related genes polymorphism is associated with the offspring BW.

Proteomics in the study of female fertility: an update

INTRODUCTION

Female fertility has been a field of interest for the scientific community throughout the years. The contribution of proteomics in the study of female fertility as well as female infertility and in vitro fertilization (IVF) has been significant. Proteomics is a recently developed field, extensively applied to the identification and quantification of proteins, which could be used as potential biomarkers in a diagnostic, prognostic, or predictive manner in a variety of medical conditions.

AREAS COVERED

The present review focuses on proteomic studies of the oocyte and endometrial environment as well as on conditions related to infertility, such as polycystic ovarian syndrome, endometriosis, obesity, and unexplained infertility. Moreover, this review presents studies that have been done in an effort to search for fertility biomarkers in individuals following the IVF procedure.

EXPERT OPINION

The comprehension of the molecular pathways behind female fertility and infertility could contribute to the diagnosis, prognosis, and prediction of infertility. Moreover, the identification of proteomic biomarkers for IVF cycles could predict the possible outcome of an IVF cycle, prevent an unsuccessful IVF, and monitor the IVF cycle in a personalized manner, leading to increased success rates. [Figure: see text].

Pre- and postnatal developmental exposure to the polychlorinated biphenyl mixture aroclor 1221 alters female rat pituitary gonadotropins and estrogen receptor alpha levels

Polychlorinated-biphenyls (PCBs) are industrial compounds, which were widely used in manufacturing of electrical parts and transformers. Despite being banned in 1979 due to human health concerns, they persist in the environment. In humans and experimental model systems, PCBs elicit toxicity in part by acting as endocrine-disrupting chemicals (EDCs). Aroclor 1221 (A1221) is a weakly estrogenic PCB mixture known to alter reproductive function in rodents. EDCs can impact hormone signaling at any level of the hypothalamic-pituitary-gonadal (HPG) axis, and we investigated the effects of A1221 exposure during the prenatal and postnatal developmental periods on pituitary hormone and steroid receptor expression in female rats. Examining offspring at 3 ages, postnatal day 8 (P8), P32 and P60, we found that prenatal exposure to A1221 increased P8 neonate pituitary luteinizing hormone beta (Lhb) mRNA and LHβ gonadotrope cell number while decreasing LH serum hormone concentration. No changes in pituitary hormone or hormone receptor gene expression were observed peri-puberty at P32. In reproductively mature rats at P60, we found pituitary follicle stimulating hormone beta (Fshb) mRNA levels increased by prenatal A1221 exposure with no corresponding alterations in FSH hormone or FSHβ expressing cell number. Estrogen receptor alpha (ERα) mRNA and protein levels were also increased at P60, but only following postnatal A1221 dosing. Together, these data illustrate that exposure to the PCB A1221, during critical developmental windows, alters pituitary gonadotropin hormone subunits and ERα levels in offspring at different phases of maturation, potentially impacting reproductive function in concert with other components of the HPG axis.

The impact of biological clock and sex hormones on the risk of disease

Molecular clocks are responsible for defining 24-h cycles of behaviour and physiology that are called circadian rhythms. Several structures and tissues are responsible for generating these circadian rhythms and are named circadian clocks. The suprachiasmatic nucleus of the hypothalamus is believed to be the master circadian clock receiving light input via the optic nerve and aligning internal rhythms with environmental cues. Studies using both in vivo and in vitro methodologies have reported the relationship between the molecular clock and sex hormones. The circadian system is directly responsible for controlling the synthesis of sex hormones and this synthesis varies according to the time of day and phase of the estrous cycle. Sex hormones also directly interact with the circadian system to regulate circadian gene expression, adjust biological processes, and even adjust their own synthesis. Several diseases have been linked with alterations in either the sex hormone background or the molecular clock. So, in this chapter we aim to summarize the current understanding of the relationship between the circadian system and sex hormones and their combined role in the onset of several related diseases.

Chromosomal and gonadal factors regulate microglial sex effects in the aging brain

Biological sex contributes to phenotypic sex effects through genetic (sex chromosomal) and hormonal (gonadal) mechanisms. There are profound sex differences in the prevalence and progression of age-related brain diseases, including neurodegenerative diseases. Inflammation of neural tissue is one of the most consistent age-related phenotypes seen with healthy aging and disease. The pro-inflammatory environment of the aging brain has primarily been attributed to microglial reactivity and adoption of heterogeneous reactive states dependent upon intrinsic (i.e., sex) and extrinsic (i.e., age, disease state) factors. Here, we review sex effects in microglia across the lifespan, explore potential genetic and hormonal molecular mechanisms of microglial sex effects, and discuss currently available models and methods to study sex effects in the aging brain. Despite recent attention to this area, significant further research is needed to mechanistically understand the regulation of microglial sex effects across the lifespan, which may open new avenues for sex informed prevention and treatment strategies.

Evidence that elevation of maternal somatic cell count could lead to production of offspring with inferior reproductive and productive performance in dairy cows during the first lactation period

Although the effect of mastitis on reproduction and production of lactating dairy cows has been vastly studied, little information is available about the association of maternal udder health status with offspring reproduction and production. Therefore, the present research was conducted to study the association between maternal average monthly somatic cell count (SCC) with reproduction, anti-Müllerian hormone (AMH) concentration, udder health status and milk production in the offspring. Based on maternal average monthly SCC (MSCC), offspring were classified into five categories including MSCC1 (SCC <200,000; n = 3005), MSCC2 (200,000 ≤ SCC <400,000; n = 252), MSCC3 (400,000 ≤ SCC <600,000; n = 103), MSCC4 (600,000 ≤ SCC <800,000; n = 40) and MSCC5 (SCC ≥800,000; n = 61). Data associated with reproduction, production and udder health status of offspring were retrieved from the herd database. In addition, blood samples were collected from a subset of offspring (n = 136) for measurement of serum AMH, as a reliable marker of ovarian reserves. Offspring in MSCC5 category had more services per conception and longer calving to conception interval than offspring in MSCC1 and MSCC2 categories (P < 0.05). The average number of SCC and risk of clinical mastitis in the offspring were not associated with MSCC (P > 0.05). But offspring in MSCC5 category produced less milk, fat and protein than offspring in MSCC1 category (P < 0.05). In addition, AMH concentration was lower in MSCC5 than MSCC1 category (P < 0.05). In conclusion, the present study showed that elevated maternal average monthly SCC could culminate in birth of offspring with inferior reproductive performance, smaller size of ovarian reserves and lower level of milk production during the first lactation period.

The Hypothalamic-Pituitary-Gonadal Axis in Men with Schizophrenia

Schizophrenia is a severe mental disorder with a chronic, progressive course. The etiology of this condition is linked to the interactions of multiple genes and environmental factors. The earlier age of onset of schizophrenia, the higher frequency of negative symptoms in the clinical presentation, and the poorer response to antipsychotic treatment in men compared to women suggests the involvement of sex hormones in these processes. This article aims to draw attention to the possible relationship between testosterone and some clinical features in male schizophrenic patients and discuss the complex nature of these phenomena based on data from the literature. PubMed, Web of Science, and Google Scholar databases were searched to select the papers without limiting the time of the publications. Hormone levels in the body are regulated by many organs and systems, and take place through the neuroendocrine, hormonal, neural, and metabolic pathways. Sex hormones play an important role in the development and function of the organism. Besides their impact on secondary sex characteristics, they influence brain development and function, mood, and cognition. In men with schizophrenia, altered testosterone levels were noted. In many cases, evidence from available single studies gave contradictory results. However, it seems that the testosterone level in men affected by schizophrenia may differ depending on the phase of the disease, types of clinical symptoms, and administered therapy. The etiology of testosterone level disturbances may be very complex. Besides the impact of the illness (schizophrenia), stress, and antipsychotic drug-induced hyperprolactinemia, testosterone levels may be influenced by, i.a., obesity, substances of abuse (e.g., ethanol), or liver damage.

TGFBR3L is associated with gonadotropin production in non-functioning gonadotroph pituitary neuroendocrine tumours

PURPOSE

Transforming growth factor-beta receptor 3-like (TGFBR3L) is a pituitary enriched membrane protein selectively detected in gonadotroph cells. TGFBR3L is named after transforming growth factor-beta receptor 3 (TGFBR3), an inhibin A co-receptor in mice, due to sequence identity to the C-terminal region. We aimed to characterize TGFBR3L detection in a well-characterized, prospectively collected cohort of non-functioning pituitary neuroendocrine tumours (NF-PitNETs) and correlate it to clinical data.

METHODS

144 patients operated for clinically NF-PitNETs were included. Clinical, radiological and biochemical data were recorded. Immunohistochemical (IHC) staining for FSHβ and LHβ was scored using the immunoreactive score (IRS), TGFBR3L and TGFBR3 were scored by the percentage of positive stained cells.

RESULTS

TGFBR3L staining was selectively present in 52% of gonadotroph tumours. TGFBR3L was associated to IRS of LHβ (median 2 [IQR 0-3] in TGFBR3L negative and median 6 [IQR 3-9] in TGFBR3L positive tumours, p < 0.001), but not to the IRS of FSHβ (p = 0.32). The presence of TGFBR3L was negatively associated with plasma gonadotropin concentrations in males (P-FSH median 5.5 IU/L [IQR 2.9-9.6] and median 3.0 [IQR 1.8-5.6] in TGFBR3L negative and positive tumours respectively, p = 0.008) and P-LH (median 2.8 IU/L [IQR 1.9-3.7] and median 1.8 [IQR 1.1-3.0] in TGFBR3L negative and positive tumours respectively, p = 0.03). TGFBR3 stained positive in 22% (n = 25) of gonadotroph tumours with no correlation to TGFBR3L.

CONCLUSION

TGFBR3L was selectively detected in half (52%) of gonadotroph NF-PitNETs. The association to LHβ staining and plasma gonadotropins suggests that TGFBR3L may be involved in hormone production in gonadotroph NF-PitNETs.

Day-night and seasonal variation of human gene expression across tissues

Circadian and circannual cycles trigger physiological changes whose reflection on human transcriptomes remains largely uncharted. We used the time and season of death of 932 individuals from GTEx to jointly investigate transcriptomic changes associated with those cycles across multiple tissues. Overall, most variation across tissues during day-night and among seasons was unique to each cycle. Although all tissues remodeled their transcriptomes, brain and gonadal tissues exhibited the highest seasonality, whereas those in the thoracic cavity showed stronger day-night regulation. Core clock genes displayed marked day-night differences across multiple tissues, which were largely conserved in baboon and mouse, but adapted to their nocturnal or diurnal habits. Seasonal variation of expression affected multiple pathways, and it was enriched among genes associated with the immune response, consistent with the seasonality of viral infections. Furthermore, they unveiled cytoarchitectural changes in brain regions. Altogether, our results provide the first combined atlas of how transcriptomes from human tissues adapt to major cycling environmental conditions. This atlas may have multiple applications; for example, drug targets with day-night or seasonal variation in gene expression may benefit from temporally adjusted doses.

Androgen receptor signaling and pyrethroids: Potential male infertility consequences

Infertility is a global health concern inflicting a considerable burden on the global economy and a severe socio-psychological impact. Approximately 15% of couples suffer from infertility globally, with a male factor contribution of approximately 50%. However, male infertility remains largely unexplored, as the burden of infertility is mostly assigned to female people. Endocrine-disrupting chemicals (EDCs) have been proposed as one of the factors causing male infertility. Pyrethroids represent an important class of EDCs, and numerous studies have associated pyrethroid exposure with impaired male reproductive function and development. Therefore, the present study investigated the potentially toxic effects of two common pyrethroids, cypermethrin and deltamethrin, on androgen receptor (AR) signaling. The structural binding characterization of cypermethrin and deltamethrin against the AR ligand-binding pocket was performed using Schrodinger's induced fit docking (IFD) approach. Various parameters were estimated, such as binding interactions, binding energy, docking score, and IFD score. Furthermore, the AR native ligand, testosterone, was subjected to similar experiments against the AR ligand-binding pocket. The results revealed commonality in the amino acid-binding interactions and overlap in other structural parameters between the AR native ligand, testosterone, and the ligands, cypermethrin and deltamethrin. The estimated binding energy values of cypermethrin and deltamethrin were very high and close to those calculated for AR native ligand, testosterone. Taken together, the results of this study suggested potential disruption of AR signaling by cypermethrin and deltamethrin, which may result in androgen dysfunction and subsequent male infertility.

Revisiting the gonadotropic regulation of mammalian spermatogenesis: evolving lessons during the past decade

Spermatogenesis is a multi-step process of male germ cell (Gc) division and differentiation which occurs in the seminiferous tubules of the testes under the regulation of gonadotropins - Follicle Stimulating Hormone (FSH) and Luteinising hormone (LH). It is a highly coordinated event regulated by the surrounding somatic testicular cells such as the Sertoli cells (Sc), Leydig cells (Lc), and Peritubular myoid cells (PTc). FSH targets Sc and supports the expansion and differentiation of pre-meiotic Gc, whereas, LH operates via Lc to produce Testosterone (T), the testicular androgen. T acts on all somatic cells e.g.- Lc, PTc and Sc, and promotes the blood-testis barrier (BTB) formation, completion of Gc meiosis, and spermiation. Studies with hypophysectomised or chemically ablated animal models and hypogonadal (hpg) mice supplemented with gonadotropins to genetically manipulated mouse models have revealed the selective and synergistic role(s) of hormones in regulating male fertility. We here have briefly summarized the present concept of hormonal control of spermatogenesis in rodents and primates. We also have highlighted some of the key critical questions yet to be answered in the field of male reproductive health which might have potential implications for infertility and contraceptive research in the future.

Population PK and Semimechanistic PK/PD Modeling and Simulation of Relugolix Effects on Testosterone Suppression in Men with Prostate Cancer

Relugolix, the first orally active, nonpeptide gonadotropin-releasing hormone receptor antagonist, is approved in the United States and the European Union for the treatment of adult patients with advanced prostate cancer. The recommended dosing regimen is a 360-mg loading dose followed by a 120-mg daily dose. Relugolix and testosterone concentration data and clinical information from two phase I studies, two phase II studies, and the phase III safety and efficacy study (HERO) were used to develop a population pharmacokinetic (PopPK) model and a semimechanistic population pharmacokinetic/pharmacodynamic (PopPK/PD) model that characterized relugolix exposure and its relationship to testosterone concentrations. Age, body weight, and Black/African American race had at most minimal effects on relugolix exposure or testosterone concentrations with no clinical relevance. Simulations using the PopPK/PD model confirmed the recommended dosing regimen of relugolix, with the median simulated testosterone concentrations predicted to achieve castration levels (< 50 ng/dL) and profound castration levels (< 20 ng/dL) by day 2 and day 9, respectively, and demonstrated that 97.3% and 85.5% of the patients remained at castration levels (< 50 ng/dL) upon temporary interruption of treatment for 7 days and 14 days, respectively. Collectively, simulations based on the PopPK and PopPK/PD models were consistent with actual data from clinical studies, reflecting the high predictiveness of the models and supporting the reliability of model-based simulations. These models can be used to provide guidance regarding dosing recommendations under various circumstances (e.g., temporary interruption of treatment, if needed) for relugolix.

Estradiol-dependent hypocretinergic/orexinergic behaviors throughout the estrous cycle

RATIONALE

The female menstrual or estrous cycle and its associated fluctuations in circulating estradiol (E2), progesterone, and other gonadal hormones alter orexin or hypocretin peptide production and receptor activity. Depending on the estrous cycle phase, the transcription of prepro-orexin mRNA, post-translational modification of orexin peptide, and abundance of orexin receptors change in a brain region-specific manner. The most dramatic changes occur in the hypothalamus, which is considered the starting point of the hypothalamic-pituitary-gonadal axis as well as the hub of orexin-producing neurons. Thus, hypothalamus-regulated behaviors, including arousal, feeding, reward processing, and the stress response depend on coordinated efforts between E2, progesterone, and the orexin system. Given the rise of orexin therapeutics for various neuropsychiatric conditions including insomnia and affective disorders, it is important to delineate the behavioral outcomes of this drug class in both sexes, as well as within different time points of the female reproductive cycle.

OBJECTIVES

Summarize how the menstrual or estrous cycle affects orexin system functionality in animal models in order to predict how orexin pharmacotherapies exert varying degrees of behavioral effects across the dynamic hormonal milieu.

Autophagy: A Double-Edged Sword in Male Reproduction

Autophagy, an evolutionarily conserved cell reprogramming mechanism, exists in all eukaryotic organisms. It is a fundamental and vital degradation/recycling pathway that removes undesirable components, such as cytoplasmic organelles, misfolded proteins, viruses, and intracellular bacteria, to provide energy and essential materials for organisms. The success of male reproduction depends on healthy testes, which are mainly composed of seminiferous tubules and mesenchyme. Seminiferous tubules are composed of Sertoli cells (SCs) and various germ cells, and the main functional part of mesenchyme are Leydig cells (LCs). In recent years, a large amount of evidence has confirmed that autophagy is active in many cellular events associated with the testes. Autophagy is not only important for testicular spermatogenesis, but is also an essential regulatory mechanism for the ectoplasmic specialization (ES) integrity of SCs, as well as for the normal function of the blood-testes barrier (BTB). At the same time, it is active in LCs and is crucial for steroid production and for maintaining testosterone levels. In this review, we expanded upon the narration regarding the composition of the testes; summarized the regulation and molecular mechanism of autophagy in SCs, germ cells, and LCs; and concluded the roles of autophagy in the process of spermatogenesis and testicular endocrinology. Through integrating the latest summaries and advances, we discuss how the role of autophagy is a double-edged sword in the testes and may provide insight for future studies and explorations on autophagy in male reproduction.