Physiology of the female reproductive axis

Abnormal Uterine Bleeding

Abnormal uterine bleeding is a common problem in premenopausal women and refers to uterine bleeding that is abnormal in frequency, duration, volume, and/or regularity. Etiologies can be classified using the PALM-COIEN system. Patients should receive a comprehensive history and physical with special attention to menstrual, sexual, and family history. Physical examination needs to include a pelvic examination with speculum and bimanual components. All patients need to have a pregnancy test and CBC with platelets. Treatments vary by etiology. Medical treatments include levonorgestrel intrauterine devices, oral contraceptive pills, and tranexamic acid. Surgical treatment options include endometrial ablation and hysterectomy.

A bioengineered in situ ovary (ISO) supports follicle engraftment and live-births post-chemotherapy

Female cancer patients who have undergone chemotherapy have an elevated risk of developing ovarian dysfunction and failure. Experimental approaches to treat iatrogenic infertility are evolving rapidly; however, challenges and risks remain that hinder clinical translation. Biomaterials have improved in vitro follicle maturation and in vivo transplantation in mice, but there has only been marginal success for early-stage human follicles. Here, we developed methods to obtain an ovarian-specific extracellular matrix hydrogel to facilitate follicle delivery and establish an in situ ovary (ISO), which offers a permissive environment to enhance follicle survival. We demonstrate sustainable follicle engraftment, natural pregnancy, and the birth of healthy pups after intraovarian microinjection of isolated exogenous follicles into chemotherapy-treated (CTx) mice. Our results confirm that hydrogel-based follicle microinjection could offer a minimally invasive delivery platform to enhance follicle integration for patients post-chemotherapy.

The Role of ROS as a Double-Edged Sword in (In)Fertility: The Impact of Cancer Treatment

Simple Summary

Tumor cells are highly resistant to oxidative stress, but beyond a certain threshold, it may lead to apoptosis/necrosis. Thus, induced loss of redox balance can be a strategy used in anticancer therapies. However, the effectiveness of drugs contrasts with unknown mechanisms involved in the loss of fertility. Considering that cancer patients’ life expectancy is increasing, it raises concerns about the unknown adverse effects. Therefore, new strategies should be pursued alongside explaining to the patients their options regarding the reproduction side effects.

Abstract

Tumor cells are highly resistant to oxidative stress resulting from the imbalance between high reactive oxygen species (ROS) production and insufficient antioxidant defenses. However, when intracellular levels of ROS rise beyond a certain threshold, largely above cancer cells’ capacity to reduce it, they may ultimately lead to apoptosis or necrosis. This is, in fact, one of the molecular mechanisms of anticancer drugs, as most chemotherapeutic treatments alter redox homeostasis by further elevation of intracellular ROS levels or inhibition of antioxidant pathways. In traditional chemotherapy, it is widely accepted that most therapeutic effects are due to ROS-mediated cell damage, but in targeted therapies, ROS-mediated effects are mostly unknown and data are still emerging. The increasing effectiveness of anticancer treatments has raised new challenges, especially in the field of reproduction. With cancer patients’ life expectancy increasing, many aiming to become parents will be confronted with the adverse effects of treatments. Consequently, concerns about the impact of anticancer therapies on reproductive capacity are of particular interest. In this review, we begin with a short introduction on anticancer therapies, then address ROS physiological/pathophysiological roles in both male and female reproductive systems, and finish with ROS-mediated adverse effects of anticancer treatments in reproduction.

Telocytes in the Female Reproductive System: Up-to-Date Knowledge, Challenges and Possible Clinical Applications

From their initial description in 2005 to this day, telocytes (TCs) have been described in the ovary, uterine tubes, uterus, vagina, mammary gland, and placenta. Their morphological features, immunophenotype, physiological functions, and roles in disease have been thoroughly documented in both animal models and human subjects. TCs, with their extremely long cytoplasmic processes called telopodes, play a pivotal role in the morphological and functional interconnection of all the components of the interstitial compartment, but also with constituents of the parenchyma. Although there is no specific immunohistochemical marker for their identification, the most cited are CD 117, CD 34, platelet-derived growth factor receptor (PDGFR), vimentin, and specific markers typical for the female reproductive system (FRS)—estrogen and progesterone receptors (ER and PR). This immunophenotype provides important clues to their physiological roles. Their main functions include the regulation of hormone-dependent processes, intercellular signaling, immune surveillance, microenvironmental maintenance, and the nursing of stem cells. In a situation where TCs are functionally or morphologically decimated, many disease entities may develop, including premature ovarian failure, endometriosis, ectopic pregnancy, infertility, preeclampsia, or even breast cancer. The common denominator of many of these conditions is that their etiopathogenesis is either partially known or completely obscure. Even though the exact role of TCs in these conditions is yet to be revealed, multiple lines of research indicate that their future clinical application may enrich diagnostic-therapeutic strategies of countless conditions. TCs are also heavily debated in terms of their possible use in regenerative medicine and tissue engineering. Some of the concepts related to TC research are strongly substantiated by experimental data, while others are highly speculative. Only future research endeavors will clearly distinguish dead-end lines of research from genuine contributions to the field.

Genome-wide Association Study of Estradiol Levels and the Causal Effect of Estradiol on Bone Mineral Density

CONTEXT

Estradiol is the primary female sex hormone and plays an important role for skeletal health in both sexes. Several enzymes are involved in estradiol metabolism, but few genome-wide association studies (GWAS) have been performed to characterize the genetic contribution to variation in estrogen levels.

OBJECTIVE

Identify genetic loci affecting estradiol levels and estimate causal effect of estradiol on bone mineral density (BMD).

DESIGN

We performed GWAS for estradiol in males (n = 147 690) and females (n = 163 985) from UK Biobank. Estradiol was analyzed as a binary phenotype above/below detection limit (175 pmol/L). We further estimated the causal effect of estradiol on BMD using Mendelian randomization.

RESULTS

We identified 14 independent loci associated (P < 5 × 10-8) with estradiol levels in males, of which 1 (CYP3A7) was genome-wide and 7 nominally (P < 0.05) significant in females. In addition, 1 female-specific locus was identified. Most loci contain functionally relevant genes that have not been discussed in relation to estradiol levels in previous GWAS (eg, SRD5A2, which encodes a steroid 5-alpha reductase that is involved in processing androgens, and UGT3A1 and UGT2B7, which encode enzymes likely to be involved in estradiol elimination). The allele that tags the O blood group at the ABO locus was associated with higher estradiol levels. We identified a causal effect of high estradiol levels on increased BMD in both males (P = 1.58 × 10-11) and females (P = 7.48 × 10-6).

CONCLUSION

Our findings further support the importance of the body's own estrogen to maintain skeletal health in males and in females.

Sex Steroid Hormones as a Balancing Factor in Oral Host Microbiome Interactions

Sex steroid hormones (SSH) are cholesterol-derived molecules. They are secreted into saliva and enter the oral cavity, triggering physiological responses from oral tissues, with possible clinical implications, such as gingival inflammation and bleeding. SSH and hormonal changes affect not only oral host cells but also oral microorganisms.

Historically, most research has focused on the effect of hormonal changes on specific bacteria and yeasts. Recently a broader effect of SSH on oral microorganisms was suggested. In order to assess the role of SSH in host-microbe interactions in the oral cavity, this review focuses on how and up to what extent SSH can influence the composition and behavior of the oral microbiome. The available literature was reviewed and a comprehensive hypothesis about the role of SSH in host-microbiome interactions is presented. The limited research available indicates that SSH may influence the balance between the host and its microbes in the oral cavity.

Immune Cell Infiltration as Signatures for the Diagnosis and Prognosis of Malignant Gynecological Tumors

Background Malignant gynecological tumors are the main cause of cancer-related deaths in women worldwide and include uterine carcinosarcomas, endometrial cancer, cervical cancer, ovarian cancer, and breast cancer. This study aims to determine the association between immune cell infiltration and malignant gynecological tumors and construct signatures for diagnosis and prognosis.

Methods We acquired malignant gynecological tumor RNA-seq transcriptome data from the TCGA database. Next, the “CIBERSORT” algorithm calculated the infiltration of 22 immune cells in malignant gynecological tumors. To construct diagnosis and prognosis signatures, step-wise regression and LASSO analyses were applied, and nomogram and immune subtypes were further identified.

Results Notably, Immune cell infiltration plays a significant role in tumorigenesis and development. There are obvious differences in the distribution of immune cells in normal, and tumor tissues. Resting NK cells, M0 Macrophages, and M1 Macrophages participated in the construction of the diagnostic model, with an AUC value of 0.898. LASSO analyses identified a risk signature including T cells CD8, activated NK cells, Monocytes, M2 Macrophages, resting Mast cells, and Neutrophils, proving the prognostic value for the risk signature. We identified two subtypes according to consensus clustering, where immune subtype 3 presented the highest risk.

Conclusion We identified diagnostic and prognostic signatures based on immune cell infiltration. Thus, this study provided a strong basis for the early diagnosis and effective treatment of malignant gynecological tumors.

Functional Gene Expression Differentiation of the Notch Signaling Pathway in Female Reproductive Tract Tissues-A Comprehensive Review With Analysis

The Notch pathway involves evolutionarily conserved signaling regulating the development of the female tract organs such as breast, ovary, cervix, and uterine endometrium. A great number of studies revealed Notch aberrancies in association with their carcinogenesis and disease progression, the management of which is still challenging. The present study is a comprehensive review of the available literature on Notch signaling during the normal development and carcinogenesis of the female tract organs. The review has been enriched with our analyses of the TCGA data including breast, cervical, ovarian, and endometrial carcinomas concerning the effects of Notch signaling at two levels: the core components and downstream effectors, hence filling the lack of global overview of Notch-driven carcinogenesis and disease progression. Phenotype heterogeneity regarding Notch signaling was projected in two uniform manifold approximation and projection algorithm dimensions, preceded by the principal component analysis step reducing the data burden. Additionally, overall and disease-free survival analyses were performed with the optimal cutpoint determination by Evaluate Cutpoints software to establish the character of particular Notch components in tumorigenesis. In addition to the review, we demonstrated separate models of the examined cancers of the Notch pathway and its targets, although expression profiles of all normal tissues were much more similar to each other than to its cancerous compartments. Such Notch-driven cancerous differentiation resulted in a case of opposite association with DFS and OS. As a consequence, target genes also show very distinct profiles including genes associated with cell proliferation and differentiation, energy metabolism, or the EMT. In conclusion, the observed Notch associations with the female tract malignancies resulted from differential expression of target genes. This may influence a future analysis to search for new therapeutic targets based on specific Notch pathway profiles.

The Emerging Key Role of Klotho in the Hypothalamus-Pituitary-Ovarian Axis

The hypothalamus-pituitary-ovary axis is the most important system for regulating female reproductive endocrine function. Its dysfunction would lead to the abnormal secretion of gonadotropin-releasing hormone, follicle-stimulating hormone, or luteinizing hormone, and eventually result in the occurrence of reproductive disease, such as congenital hypogonadotropic hypogonadism, polycystic ovary syndrome, and premature ovarian failure. Recently, an anti-aging gene, Klotho, has gained broad attention in female reproductive diseases. Reports have shown that Klotho is closely correlated to the hypothalamus-pituitary-ovary axis and plays a key role in the development and progression of reproductive diseases. With this issue, we generally review the physiological and pathological role of Klotho in the hypothalamus-pituitary-ovary axis. We also review the underlying mechanisms of Klotho in promoting and preventing female reproductive diseases, which involve the dysfunction of the fibroblast growth factor-Klotho endocrine system, the abnormal signaling regulation of Wnt-β-catenin and insulin-like growth factor-1, the accumulation of oxidative stress, and the inhibition of autophagy, eventually affecting the genesis, development, ovulation, or atresia of follicles. The present review would provide new insights and potential therapeutic target strategies for clinical strategies.

Bisphenol A: an emerging threat to female fertility

Bisphenol-A (BPA) has been reported to be associated to female infertility. Indeed, BPA has been found to be more frequently detected in infertile women thus leading to hypothesize a possible effect of BPA on natural conception and spontaneous fecundity. In addition, in procedures of medically assisted reproduction BPA exposure has been found to be negatively associated with peak serum estradiol levels during gonadotropin stimulation, number of retrieved oocytes, number of normally fertilized oocytes and implantation. BPA deleterious effects are more critical during perinatal exposure, causing dysregulation of hypothalamic-pituitary-ovarian axis in pups and adults, with a precocious maturation of the axis through a damage of GnRH pulsatility, gonadotropin signaling and sex steroid hormone production. Further, BPA exposure during early lifestage may have a transgenerational effect predisposing the subsequent generations to the risk of developing BPA related disease. Experimental studies suggested that prenatal, perinatal and postnatal exposure to BPA can impair several steps of ovarian development, induce ovarian morphology rearrangement and impair ovarian function, particularly folliculogenesis, as well as can impair uterus morphology and function, in female adult animal and offspring. Finally, studies carried out in animal models have been reported the occurrence of endometriosis-like lesions after BPA exposure. Moreover, BPA exposure has been described to encourage the genesis of PCOS-like abnormalities through the impairment of the secretion of sex hormones affecting ovarian morphology and functions, particularly folliculogenesis. The current manuscript summarizes the evidence regarding the association between BPA exposure and female infertility, reviewing both clinical and preclinical studies.

Interaction of Long Noncoding RNAs and Notch Signaling: Implications for Tissue Homeostasis Loss

The Notch signaling is a crucial pathway involved in cellular development, progression, and differentiation. Deregulation of Notch signaling pathway commonly impacts tissue homeostasis, being highly associated with proliferative disorders. The long noncoding RNAs (lncRNAs), which are transcripts with more than 200 nucleotides that do not code for proteins, were already described as Notch signaling pathway-interacting molecules. Many of them act as important transcriptional and posttranscriptional regulators, affecting gene expression and targeting other regulatory molecules, such as miRNAs. Due to their strong impact on function and gene expression of Notch-related molecules, lncRNAs influence susceptibility to cancer and other diseases, and can be regarded as potential biomarkers and therapeutic targets. Along this chapter, we summarize the cross talk between the Notch signaling pathway and their most important modulating lncRNAs, as well as the pathological consequences of these interactions, in different tissues.

Regulation effect and mechanism of Sheng-Hua-Tang on female reproductive system: From experimental transcriptomic analysis to clinical applications

ETHNOPHARMACOLOGICAL RELEVANCE

Sheng-Hua-Tang (SHT) is commonly used to treat female illnesses, especially postpartum conditioning. However, its effects and mechanisms on female reproductive system remain unclear. The aim of the present study was to investigate the effect of SHT on female brain-ovary-uterus axis from bench to clinic.

MATERIALS AND METHODS

Mice were administrated SHT (200 mg/kg) orally for seven consecutive days. Brain, ovary, and uterus tissues were then collected for microarray analysis. A nationwide database analysis and a pilot randomized, open-label clinical trial were further applied to evaluate the clinical application and effects of SHT on postpartum women.

RESULTS

Microarray analysis showed that oral administration of SHT induced a cascade reaction of gene expression, with 17, 883, and 1592 genes were significantly regulated by SHT in brain, ovary, and uterus, respectively. Population-based analysis of one million subjects in Taiwan's National Health Insurance Research Database between 1997 and 2013 showed that SHT was commonly used in menstrual disorders in female population, especially dysmenorrhea, abnormal uterine bleeding, and variation of menstrual cycle. Clinical trial on postpartum women showed that oral administration SHT for one week alleviated uterine contraction pain and breast swelling pain. Furthermore, Mmp2, Mmp3, Mmp9, Mmp11, Mmp15, Oxtr, Plrl, and Tph2 gene expression affected by SHT in mice were correlated with clinical effects of SHT in human subjects.

CONCLUSION

This report provided the scientific evidences of mechanisms and clinical efficacies of SHT. Moreover, our findings might afford insights for clinical doctors in terms of SHT prescription.

Update on primary ovarian insufficiency in adolescents

PURPOSE OF REVIEW

We provide an overview of new insights into the genetic causes of primary ovarian insufficiency (POI) and address the challenges faced by clinicians who care for adolescents with this condition.

RECENT FINDINGS

In most cases, the cause of POI remains a mystery after appropriate clinical testing has been completed. Large-scale genomic sequencing approaches are uncovering new mechanisms underlying the disorder. Gene variants that affect the normal processes of primordial germ-cell proliferation and migration, oocyte meiosis, and ovarian follicle formation/activation are plausible mechanisms. Whole exome sequencing has been used to associate many of these variants with human POI. POI is a serious chronic condition with no cure. It qualifies as a rare disease and as such presents special challenges to patients, parents, and clinicians. Although the diagnosis of POI is often delayed because of the assumption that irregular menses are common among adolescents, early detection is critical for the maintenance of bone and cardiovascular health. Treatment options have focused on hormonal therapy and fertility preservation. However, many studies prove the increasing need to incorporate mental health support and a family systems approach into the management plan.

SUMMARY

Large-scale genomic sequencing has recently identified new mechanisms of POI. However, at present this testing is not clinically indicated as routine. Practice will change as genomic medicine is integrated into standard care. Adolescents with POI are best served by an integrated personal care approach centered on the patient and provided by a primary care clinician who has support from a multidisciplinary team.

Artemisinin induces hormonal imbalance and oxidative damage in the erythrocytes and uterus but not in the ovary of rats

Artemisinin is an antimalarial drug previously reported to induce neurotoxicity and embryotoxicity in animal models. This study investigated the erythrocytes and reproductive toxicity potentials of artemisinin in female rats. Animals were randomly divided into four study groups of eight rats each. The control group (group I) received corn oil, the vehicle, while groups II-IV were orally exposed to 7, 35 and 70 mg kg(-1) day(-1) of artemisinin, respectively, by gastric intubation for 7 consecutive days. Subsequently, we evaluated the impact of artemisinin on the endocrine environment and selected markers of oxidative damage and antioxidant status of the erythrocytes, ovary and uterus. Artemisinin significantly increased hydrogen peroxide (H2O2) and malondialdehyde (MDA) levels and decreased catalase, glutathione peroxidase and superoxide dismutase activities in erythrocytes and uterus of rats compared with control group (p < 0.05). However, artemisinin did not alter ovarian MDA, H2O2, glutathione levels and catalase activity, while ovarian and uterine histological assessment revealed absence of visible lesions. Moreover, artemisinin significantly decreased follicle-stimulating hormone and increased progesterone levels compared with control (p < 0.05). Thus, these data suggest that in the absence of malarial parasite infection, artemisinin induced hormonal imbalance and oxidative damage in the erythrocytes and uterus but spared the ovary of rats.