Physiology of the Endometrium and Regulation of Menstruation

Vaginal Progesterone to Prevent Spontaneous Preterm Birth in Women With a Sonographic Short Cervix: The Story of the PREGNANT Trial

The PREGNANT trial was a randomized, placebo-controlled, multicenter trial designed to determine the efficacy and safety of vaginal progesterone (VP) to reduce the risk of birth < 33 weeks and of neonatal complications in women with a sonographic short cervix (10 to 20 mm) in the mid-trimester (19 to 23 6/7 wk). Patients allocated to receive VP had a 45% lower rate of preterm birth (8.9% vs 16.1%; relative risk = 0.55; 95% CI: 0.33-0.92). Neonates born to mothers allocated to VP had a 60% reduction in the rate of respiratory distress syndrome. This article reviews the background, design, execution, interpretation, and impact of the PREGNANT Trial.

Abnormal uterine bleeding: The well-known and the hidden face

Abnormal uterine bleeding (AUB) is a bleeding from the uterine corpus that is abnormal in regularity, volume, frequency or duration. It encompasses heavy menstrual bleeding, irregular menstrual bleeding and intermenstrual bleeding, which are common symptoms among women of reproductive age, impacting their overall well-being. Menstruation involves interactions between endometrial epithelial and stromal cells, immune cell influx, and changes in endometrial vasculature. These events resemble an inflammatory response with increased vessel permeability, tissue breakdown, and the arrival of innate immune cells. However, the mechanisms of menstrual cessation are poorly understood. AUB can be related to structural causes (polyp, adenomyosis, leiomyoma, malignancy/hyperplasia) and nonstructural conditions (coagulopathy, ovulatory dysfunction, endometrial, iatrogenic). While transvaginal ultrasound is the primary method for the screening of intracavitary lesions, saline infusion sonohysterography is more accurate to detect endometrial polyps and submucous leiomyomas, while hysteroscopy with biopsy remains the reference method for a definitive diagnosis. The main goals in managing AUB are addressing and correcting the underlying primary cause, if possible, and establishing a regular bleeding pattern or amenorrhea, which can be done with antifibrinolytic agents, progestins, gonadotropin-releasing hormone agonists and antagonists, or surgical interventions, each one with specific indications and limitations. Further research is necessary to assess the effectiveness and the long-term effects of various medical and surgical treatments. Meanwhile, the availability of diagnostic methods such as transvaginal ultrasound and hysteroscopy and the universal distribution of medical treatments for AUB should be prioritized by policymakers to minimize the diagnostic and treatment delay and thus reduce the risk of AUB-related anemia and the need of hysterectomy.

Bioengineering approaches for the endometrial research and application

The endometrium undergoes a series of precise monthly changes under the regulation of dynamic levels of ovarian hormones that are characterized by repeated shedding and subsequent regeneration without scarring. This provides the potential for wound healing during endometrial injuries. Bioengineering materials highlight the faithful replication of constitutive cells and the extracellular matrix that simulates the physical and biomechanical properties of the endometrium to a larger extent. Significant progress has been made in this field, and functional endometrial tissue bioengineering allows an in-depth investigation of regulatory factors for endometrial and myometrial defects in vitro and provides highly therapeutic methods to alleviate obstetric and gynecological complications. However, much remains to be learned about the latest progress in the application of bioengineering technologies to the human endometrium. Here, we summarize the existing developments in biomaterials and bioengineering models for endometrial regeneration and improving the female reproductive potential.

Injury Incidence, Severity, and Type Across the Menstrual Cycle in Female Footballers: A Prospective Three Season Cohort Study

PURPOSE

The aim of the study was to assess the influence of menstrual cycle phase on injury incidence, severity, and type in elite female professional footballers over three seasons.

METHODS

Time-loss injuries and menstrual cycle data were prospectively recorded for 26 elite female football players across three seasons. The menstrual cycle was categorized into four phases using a standardized model: menstruation (phase 1; P1), remainder of follicular phase (phase 2; P2), early luteal (phase 3; P3), and premenstrual phase (phase 4; P4). Injury incidence rates (IIR) and ratios (IIRR) were calculated for overall injuries, injury severity, type, contact vs noncontact, and game/training.

RESULTS

A total of 593 cycles across 13,390 d were tracked during the study, and 74 injuries from 26 players were eligible for analysis. When comparing IIR between phases (reference: P1), overall injury rates were highest in P4 (IIRR, 2.30 (95% confidence interval, 0.99-5.34; P = 0.05)). When examining rates by injury severity and type, IIR values were also highest in P4 for ≤7 d' time-loss (4.40 (0.93-20.76; P = 0.06)), muscle-specific (6.07 (1.34-27.43; P = 0.02)), and noncontact (3.05 (1.10-8.50; P = 0.03)) injuries. Muscle-specific (IIRR P3/P1, 5.07 (1.16-22.07; P = 0.03)) and ≤7 d' time-loss (4.47 (1.01-19.68; P = 0.05)) injury risk was also significantly higher in P3. Muscle injuries were the most prevalent subtype ( n = 41). No anterior cruciate ligament injuries were recorded across the monitoring period.

CONCLUSIONS

Injury risk was significantly elevated during the luteal phase of the menstrual cycle (P3 and P4) among elite female professional footballers. Further research is urgently needed to better understand the influence of the menstrual cycle on injury risk and to develop interventions to mitigate risk.

Evolution of biotechnological advances and regenerative therapies for endometrial disorders: a systematic review

BACKGROUND

The establishment and maintenance of pregnancy depend on endometrial competence. Asherman syndrome (AS) and intrauterine adhesions (IUA), or endometrial atrophy (EA) and thin endometrium (TE), can either originate autonomously or arise as a result from conditions (i.e. endometritis or congenital hypoplasia), or medical interventions (e.g. surgeries, hormonal therapies, uterine curettage or radiotherapy). Affected patients may present an altered or inadequate endometrial lining that hinders embryo implantation and increases the risk of poor pregnancy outcomes and miscarriage. In humans, AS/IUA and EA/TE are mainly treated with surgeries or pharmacotherapy, however the reported efficacy of these therapeutic approaches remains unclear. Thus, novel regenerative techniques utilizing stem cells, growth factors, or tissue engineering have emerged to improve reproductive outcomes.

OBJECTIVE AND RATIONALE

This review comprehensively summarizes the methodologies and outcomes of emerging biotechnologies (cellular, acellular, and bioengineering approaches) to treat human endometrial pathologies. Regenerative therapies derived from human tissues or blood which were studied in preclinical models (in vitro and in vivo) and clinical trials are discussed.

SEARCH METHODS

A systematic search of full-text articles available in PubMed and Embase was conducted to identify original peer-reviewed studies published in English between January 2000 and September 2023. The search terms included: human, uterus, endometrium, Asherman syndrome, intrauterine adhesions, endometrial atrophy, thin endometrium, endometritis, congenital hypoplasia, curettage, radiotherapy, regenerative therapy, bioengineering, stem cells, vesicles, platelet-rich plasma, biomaterials, microfluidic, bioprinting, organoids, hydrogel, scaffold, sheet, miRNA, sildenafil, nitroglycerine, aspirin, growth hormone, progesterone, and estrogen. Preclinical and clinical studies on cellular, acellular, and bioengineering strategies to repair or regenerate the human endometrium were included. Additional studies were identified through manual searches.

OUTCOMES

From a total of 4366 records identified, 164 studies (3.8%) were included for systematic review. Due to heterogeneity in the study design and measured outcome parameters in both preclinical and clinical studies, the findings were evaluated qualitatively and quantitatively without meta-analysis. Groups using stem cell-based treatments for endometrial pathologies commonly employed mesenchymal stem cells (MSCs) derived from the human bone marrow or umbilical cord. Alternatively, acellular therapies based on platelet-rich plasma (PRP) or extracellular vesicles are gaining popularity. These are accompanied by the emergence of bioengineering strategies based on extracellular matrix (ECM)-derived hydrogels or synthetic biosimilars that sustain local delivery of cells and growth factors, reporting promising results. Combined therapies that target multiple aspects of tissue repair and regeneration remain in preclinical testing but have shown translational value. This review highlights the myriad of therapeutic material sources, administration methods, and carriers that have been tested.

WIDER IMPLICATIONS

Therapies that promote endometrial proliferation, vascular development, and tissue repair may help restore endometrial function and, ultimately, fertility. Based on the existing evidence, cost, accessibility, and availability of the therapies, we propose the development of triple-hit regenerative strategies, potentially combining high-yield MSCs (e.g. from bone marrow or umbilical cord) with acellular treatments (PRP), possibly integrated in ECM hydrogels. Advances in biotechnologies together with insights from preclinical models will pave the way for developing personalized treatment regimens for patients with infertility-causing endometrial disorders such as AS/IUA, EA/TE, and endometritis.

REGISTRATION NUMBER

https://osf.io/th8yf/.

Excessive proliferating cell nuclear antigen attenuates endometrial adhesive capacity and decidualization in patients with recurrent implantation failure

STUDY QUESTION

Does the expression of proliferating cell nuclear antigen (PCNA) in the endometrium regulate endometrial receptivity in patients with recurrent implantation failure (RIF)?

SUMMARY ANSWER

A high abundance of PCNA attenuates endometrial adhesive capacity and decidualization in patients with RIF.

WHAT IS KNOWN ALREADY

Aberrant expression of PCNA has been discovered in multiple infertility-related disorders. However, the expression pattern and role of PCNA in the establishment of endometrial receptivity and endometrial decidualization in patients with RIF remain unclear.

STUDY DESIGN, SIZE, DURATION

We analysed the expression of PCNA in mid-secretory endometrial tissues from 24 patients with RIF and 24 healthy women. Additionally, PCNA expression levels were measured in proliferative and mid-secretory phase endometrial tissue samples from women with regular menstrual cycles and in decidual tissue samples taken from ten women during normal early pregnancy (n = 10 per phase for each group). The function and regulatory mechanisms of PCNA in endometrial adhesive capacity and endometrial decidualization were investigated using BeWo spheroids, Ishikawa cells, and human endometrial stromal cells (HESCs).

PARTICIPANTS/MATERIALS, SETTING, METHODS

The expression of PCNA in mid-secretory endometrial tissues of patients with RIF and women with normal endometrium and in endometrial tissue at different stages of the menstrual cycle and in decidualized tissues was analysed by RT-qPCR, western blot, and immunohistochemistry staining (IHC). Furthermore, the number of BeWo spheroids directly attached to the Ishikawa cell monolayers, and the potential molecular mechanisms involved, were compared between cells overexpressing PCNA and a control group. Additionally, the effect and regulatory mechanisms of PCNA on the decidualization of HESCs in vitro were investigated.

MAIN RESULTS AND THE ROLE OF CHANCE

Our findings indicated that the abundance of PCNA was dramatically greater in mid-secretory endometrial tissues from patients with RIF than in those from women with healthy endometrium. The expression of PCNA increased in the proliferative phase of the menstrual cycle but decreased gradually in the mid-secretory phase and in decidual tissues. Interestingly, PCNA was expressed in both human endometrial epithelial cells (HEECs) and HESCs. In Ishikawa cells, PCNA overexpression dramatically reduced the endometrial adhesive capacity by inhibiting the expression of adhesion molecules (E-cadherin and integrin β3) and activating the FAK/paxillin signalling pathway. Furthermore, in HESCs, PCNA overexpression attenuated endometrial decidualization by activating the AKT/β-catenin signalling pathway and increasing tight junctions between cells by upregulating ZO-1 and occludin expression. In addition, PCNA-ELAVL1 interactions were confirmed by coimmunoprecipitation in decidualized HESCs.

LARGE SCALE DATA

N/A.

LIMITATIONS, REASONS FOR CAUTION

The functional analysis of PCNA was limited by the number of human endometrial tissues. A larger sample size is required to further explore the potential roles of PCNA during embryo implantation. Moreover, the present results should be taken with caution, as only a few of the embryos that were transferred in RIF patients population underwent preimplantation genetic testing for embryonic chromosome aneuploidies (PGT-A), despite embryo ploidy testing being significant in the diagnosis of unexplained RIF.

WIDER IMPLICATIONS OF THESE FINDINGS

High PCNA expression attenuates endometrial adhesive capacity and decidualization in patients with RIF. These findings provide new insights into the potential mechanisms underlying the occurrence of implantation failure.

STUDY FUNDING/COMPETING INTEREST(S)

This work was supported by the National Natural Science Foundation of China (82101698), Shandong Provincial Natural Science Foundation (ZR2021MH012), and the Science and Technology Plan of Yantai (2023YD021 and 2022YD031). The authors have no conflicts of interest to disclose.

TRIAL REGISTRATION NUMBER

N/A.

Injectable, stable, and biodegradable hydrogel with platelet-rich plasma induced by l-serine and sodium alginate for effective treatment of intrauterine adhesions

The combination of pharmacological and physical barrier therapy is a highly promising strategy for treating intrauterine adhesions (IUAs), but there lacks a suitable scaffold that integrates good injectability, proper mechanical stability and degradability, excellent biocompatibility, and non-toxic, non-rejection therapeutic agents. To address this, a novel injectable, degradable hydrogel composed of poly(ethylene glycol) diacrylate (PEGDA), sodium alginate (SA), and l-serine, and loaded with platelet-rich plasma (PRP) (referred to as PSL-PRP) is developed for treating IUAs. l-Serine induces rapid gelation within 1 min and enhances the mechanical properties of the hydrogel, while degradable SA provides the hydrogel with strength, toughness, and appropriate degradation capabilities. As a result, the hydrogel exhibits an excellent scaffold for sustained release of growth factors in PRP and serves as an effective physical barrier. In vivo testing using a rat model of IUAs demonstrates that in situ injection of the PSL-PRP hydrogel significantly reduces fibrosis and promotes endometrial regeneration, ultimately leading to fertility restoration. The combined advantages make the PSL-PRP hydrogel very promising in IUAs therapy and in preventing adhesions in other internal tissue wounds.

Endometrial Proliferative Phase-Centered View of Transcriptome Dynamics across the Menstrual Cycle

The endometrium, the inner mucosal lining of the uterus, undergoes complex molecular and cellular changes across the menstrual cycle in preparation for embryo implantation. Transcriptome-wide analyses have mainly been utilized to study endometrial receptivity, the prerequisite for successful implantation, with most studies, so far, comparing the endometrial transcriptomes between (i) secretory and proliferative endometrium or (ii) mid-secretory and early secretory endometrium. In the current study, we provide a complete transcriptome description of the endometrium across the entire menstrual cycle and, for the first time, comprehensively characterize the proliferative phase of the endometrium. Our temporal transcriptome analysis includes five time points including the mid-proliferative, late proliferative (peri-ovulatory phase), early secretory, mid-secretory, and late secretory phases. Thus, we unveil exhaustively the transitions between the consecutive proliferative and secretory phases, highlighting their unique gene expression profiles and possible distinct biological functions. The transcriptome analysis reveals many differentially expressed genes (DEGs) across the menstrual cycle, most of which are phase-specific. As an example of coordinated gene activity, the expression profile of histone-encoding genes within the HIST cluster on chromosome 6 shows an increase in cluster activity during the late proliferative and a decline during the mid-secretory phase. Moreover, numerous DEGs are shared among all phases. In conclusion, in the current study, we delineate the endometrial proliferative phase-centered view of transcriptome dynamics across the menstrual cycle. Our data analysis highlights significant transcriptomic and functional changes occurring during the late proliferative phase-an essential transition point from the proliferative phase to the secretory phase. Future studies should explore how the biology of the late proliferative phase endometrium impacts the achievement of mid-secretory endometrial receptivity or contributes to molecular aberrations leading to embryo implantation failure.

Exosomes Derived from Mesenchymal Stem Cells Increase the Viability of Damaged Endometrial Cells via the miR-99b-5p/PCSK9 Axis

The aim of this article was to investigate whether exosomes derived from bone marrow mesenchymal stem cells repair damaged endometrial stromal cells (EnSCs) through the miR-99b-5p/PCSK9 axis. Exosomes derived from bone marrow mesenchymal stem cells (BMSC-exos) were isolated by ultracentrifugation and characterized using transmission electron microscopy and nanoflow cytometry. A mifepristone-induced EnSC injury model was established in vitro, and the uptake of BMSC-exos was assessed. EnSCs were divided into three groups: the normal group (ctrl), EnSC injury group (model), and BMSC-exo treatment group. The effects of BMSC-exos on EnSC proliferation, apoptosis, and vascular endothelial growth factor (VEGF) expression were assessed by coculturing MSC-exos with endometrial cells. Furthermore, high-throughput sequencing was used to identify differentially expressed genes (DEGs). Through bioinformatics analysis, reverse transcription-quantitative polymerase chain reaction, western blotting, the CCK8 assay, immunohistochemistry, and dual-luciferase experiments, the potential mechanism by which BMSC-exos-derived miRNAs repair EnSC injury was studied. BMSC-exos expressed the marker proteins CD9 and CD63. Laser confocal microscopy showed that BMSC-exos could enter damaged EnSCs. In the BMSC-exos-EnSC coculture group compared with the model group, BMSC-exos significantly increased the proliferation of damaged EnSCs and inhibited cell apoptosis in a dose-dependent manner. The expression levels of Caspase-3, Caspase-9, Bax, and VEGF mRNA were significantly downregulated in the BMSC-exos-EnSC coculture group, whereas Bcl-2 expression was upregulated. We identified 28 overlapping DEGs between the model and ctrl groups and between the BMSC-exo and model groups. Transfection with miR-99b-5p mimics significantly decreased PCSK9 gene expression and inhibited the expression of the autophagy-related proteins Beclin-1 and LC3-II/I and apoptosis, thereby promoting EnSC proliferation. Transfection with a miR-99b-5p inhibitor showed the opposite effects. Beclin-1, LC3-II/I, and PCSK9 expression in the thin endometrium was significantly increased. miR-99b-5p promoted cell proliferation by targeting PCSK9. BMSC-exos promoted endometrial proliferation, and miR-99b-5p inhibited cell apoptosis and promoted EnSC proliferation by targeting PCSK9, providing a new target for the treatment of thin endometrium.

Interleukin 6 at menstruation promotes the proliferation and self-renewal of endometrial mesenchymal stromal/stem cells through the WNT/β-catenin signaling pathway

Background

At menstruation, the functional layer of the human endometrium sheds off due to the trigger of the release of inflammatory factors, including interleukin 6 (IL-6), as a result of a sharp decline in progesterone levels, leading to tissue breakdown and bleeding. The endometrial mesenchymal stem-like cells (CD140b+CD146+ eMSC) located in the basalis are responsible for the cyclical regeneration of the endometrium after menstruation. Endometrial cells from the menstruation phase have been proven to secrete a higher amount of IL-6 and further enhance the self-renewal and clonogenic activity of eMSC. However, the IL-6-responsive mechanism remains unknown. Thus, we hypothesized that IL-6 secreted from niche cells during menstruation regulates the proliferation and self-renewal of eMSC through the WNT/β-catenin signaling pathway.

Methods

In this study, the content of IL-6 across the menstrual phases was first evaluated. Coexpression of stem cell markers (CD140b and CD146) with interleukin 6 receptor (IL-6R) was confirmed by immunofluorescent staining. In vitro functional assays were conducted to investigate the effect of IL-6 on the cell activities of eMSC, and the therapeutic role of these IL-6- and WNT5A-pretreated eMSC on the repair of injured endometrium was observed using an established mouse model.

Results

The endometrial cells secrete a high amount of IL-6 under hypoxic conditions, which mimic the physiological microenvironment in the menstruation phase. Also, the expression of IL-6 receptors was confirmed in our eMSC, indicating their capacity to respond to IL-6 in the microenvironment. Exogenous IL-6 can significantly enhance the self-renewal, proliferation, and migrating capacity of eMSC. Activation of the WNT/β-catenin signaling pathway was observed upon IL-6 treatment, while suppression of the WNT/β-catenin signaling impaired the stimulatory role of IL-6 on eMSC activities. IL-6- and WNT5A-pretreated eMSC showed better performance during the regeneration of the injured mouse endometrium.

Conclusion

We demonstrate that the high level of IL-6 produced by endometrial cells at menstruation can induce the stem cells in the human endometrium to proliferate and migrate through the activation of the WNT/β-catenin pathway. Treatment of eMSC with IL-6 and WNT5A might enhance their therapeutic potential in the regeneration of injured endometrium.

Incorporation of Decidual Stromal Cells Derived Exosomes in Sodium Alginate Hydrogel as an Innovative Therapeutic Strategy for Advancing Endometrial Regeneration and Reinstating Fertility

Intrauterine adhesion (IUA) stands as a prevalent medical condition characterized by endometrial fibrosis and scar tissue formation within the uterine cavity, resulting in infertility and, in severe cases, recurrent miscarriages. Cell therapy, especially with stem cells, offers an alternative to surgery, but concerns about uncontrolled differentiation and tumorigenicity limit its use. Exosomes, more stable and immunogenicity-reduced than parent cells, have emerged as a promising avenue for IUA treatment. In this study, a novel approach has been proposed wherein exosomes originating from decidual stromal cells (DSCs) are encapsulated within sodium alginate hydrogel (SAH) scaffolds to repair endometrial damage and restore fertility in a mouse IUA model. Current results demonstrate that in situ injection of DSC-derived exosomes (DSC-exos)/SAH into the uterine cavity has the capability to induce uterine angiogenesis, initiate mesenchymal-to-epithelial transformation (MET), facilitate collagen fiber remodeling and dissolution, promote endometrial regeneration, enhance endometrial receptivity, and contribute to the recovery of fertility. RNA sequencing and advanced bioinformatics analysis reveal miRNA enrichment in exosomes, potentially supporting endometrial repair. This finding elucidates how DSC-exos/SAH mechanistically fosters collagen ablation, endometrium regeneration, and fertility recovery, holding the potential to introduce a novel IUA treatment and offering invaluable insights into the realm of regenerative medicine.

Cell Chirality of Micropatterned Endometrial Microvascular Endothelial Cells

Chirality is an intrinsic cellular property that describes cell polarization biases along the left-right axis, apicobasal axis, or front-rear axes. Cell chirality plays a significant role in the arrangement of organs in the body as well as in the orientation of organelles, cytoskeletons, and cells. Vascular networks within the endometrium, the mucosal inner lining of the uterus, commonly display spiral architectures that rapidly form across the menstrual cycle. Herein, the role of endometrial-relevant extracellular matrix stiffness, composition, and soluble signals on endometrial endothelial cell chirality is systematically examined using a high-throughput microarray. Endometrial endothelial cells display marked patterns of chirality as individual cells and as cohorts in response to substrate stiffness and environmental cues. Vascular networks formed from endometrial endothelial cells also display shifts in chirality as a function of exogenous hormones. Changes in cellular-scale chirality correlate with changes in vascular network parameters, suggesting a critical role for cellular chirality in directing endometrial vessel network organization.

Impact of DEHP exposure on female reproductive health: Insights into uterine effects

Several endocrine disrupting compounds released from plastics, including polyfluoroalkyl substances, bisphenols, flame retardants, phthalates and others, are of great concern to human health due to their high toxicity. This review discusses the effects of di-(2-ethylhexyl) phthalate (DEHP), the most common member of the phthalate family, on female reproduction. In vitro and in vivo studies link DEHP exposure to impaired hypothalamic-pituitary-ovarian s (HPO) axis function, alteration of steroid-hormone levels and dysregulation of their receptors, and changes in uterine morphophysiology. In addition, high urinary DEPH levels have been associated with several reproductive disorders in women, including endometriosis, fibromyoma, fetal growth restriction and pregnancy loss. These data suggest that DEHP may be involved in the pathophysiology of various female reproductive diseases. Therefore, exposure to these compounds should be considered a concern in clinician surveillance practices for women at reproductive age and should be regulated to protect their health and that of their progeny.

Determinants of dysmenorrhoea among female adolescents: results from a community-based cohort study in Amsterdam

RESEARCH QUESTION

What is the contribution of sociodemographic, psychosocial, lifestyle and reproductive factors up to the age of 11-12 years to the occurrence of dysmenorrhoea at age 15-16 years within the Amsterdam Born Children and their Development (ABCD) study?

DESIGN

Data of 1038 female adolescents were used. Participants' baseline characteristics were obtained using self-reported questionnaires up to the age of 11-12 years, as well as the obstetric information of their mothers during pregnancy. Dysmenorrhoea was assessed at the age of 15-16 years, and was deemed to be present if an adolescent reported menstrual abdominal and/or back pain and therefore took medication and/or hormonal contraception. Using a backward selection approach, potential determinants of dysmenorrhoea were selected and multivariable associations were determined.

RESULTS

The overall prevalence of dysmenorrhoea was 49.5% among the participants. Intake of 3-4.5 sugar-sweetened beverages/day (P = 0.035) and higher gynaecological age (i.e. years since menarche) (P < 0.001) were significantly associated with higher occurrence of dysmenorrhoea in the final model, which explained 8.1% of the total variance in the occurrence of dysmenorrhoea. No significant associations were found between the occurrence of dysmenorrhoea and sociodemographic or psychosocial factors.

CONCLUSIONS

This investigation of various potential risk factors for dysmenorrhoea suggests that diet and reproductive factors are particularly important predictors of the occurrence of dysmenorrhoea among young adolescents. Specifically, intake of sugar-sweetened beverages and higher gynaecological age were predictive of the occurrence of dysmenorrhoea. Other lifestyle factors were also identified as possible risk factors. Using this knowledge, effective strategies can be developed to reduce the burden of dysmenorrhoea among adolescents, and to provide appropriate care for those suffering from the condition.

Minerals and the Menstrual Cycle: Impacts on Ovulation and Endometrial Health

The role of minerals in female fertility, particularly in relation to the menstrual cycle, presents a complex area of study that underscores the interplay between nutrition and reproductive health. This narrative review aims to elucidate the impacts of minerals on key aspects of the reproductive system: hormonal regulation, ovarian function and ovulation, endometrial health, and oxidative stress. Despite the attention given to specific micronutrients in relation to reproductive disorders, there is a noticeable absence of a comprehensive review focusing on the impact of minerals throughout the menstrual cycle on female fertility. This narrative review aims to address this gap by examining the influence of minerals on reproductive health. Each mineral's contribution is explored in detail to provide a clearer picture of its importance in supporting female fertility. This comprehensive analysis not only enhances our knowledge of reproductive health but also offers clinicians valuable insights into potential therapeutic strategies and the recommended intake of minerals to promote female reproductive well-being, considering the menstrual cycle. This review stands as the first to offer such a detailed examination of minerals in the context of the menstrual cycle, aiming to elevate the understanding of their critical role in female fertility and reproductive health.

Single-cell analysis reveals insights into epithelial abnormalities in ovarian endometriosis

Ovarian endometriosis is characterized by the growth of endometrial tissue within the ovary, causing infertility and chronic pain. However, its pathophysiology remains unclear. Utilizing high-precision single-cell RNA sequencing, we profile the normal, eutopic, and ectopic endometrium from 34 individuals across proliferative and secretory phases. We observe an increased proportion of ciliated cells in both eutopic and ectopic endometrium, characterized by a diminished expression of estrogen sulfotransferase, which likely confers apoptosis resistance. After translocating to ectopic lesions, endometrial epithelium upregulates nicotinamide N-methyltransferase expression that inhibits apoptosis by promoting deacetylation and subsequent nuclear exclusion of transcription factor forkhead box protein O1, thereby leading to the downregulation of the apoptotic gene BIM. Moreover, epithelial cells in ectopic lesions elevate HLA class II complex expression, which stimulates CD4+ T cells and consequently contributes to chronic inflammation. Altogether, our study provides a comprehensive atlas of ovarian endometriosis and highlights potential therapeutic targets for modulating apoptosis and inflammation.

Roles of bone morphogenetic proteins in endometrial remodeling during the human menstrual cycle and pregnancy

BACKGROUND

During the human menstrual cycle and pregnancy, the endometrium undergoes a series of dynamic remodeling processes to adapt to physiological changes. Insufficient endometrial remodeling, characterized by inadequate endometrial proliferation, decidualization and spiral artery remodeling, is associated with infertility, endometriosis, dysfunctional uterine bleeding, and pregnancy-related complications such as preeclampsia and miscarriage. Bone morphogenetic proteins (BMPs), a subset of the transforming growth factor-β (TGF-β) superfamily, are multifunctional cytokines that regulate diverse cellular activities, such as differentiation, proliferation, apoptosis, and extracellular matrix synthesis, are now understood as integral to multiple reproductive processes in women. Investigations using human biological samples have shown that BMPs are essential for regulating human endometrial remodeling processes, including endometrial proliferation and decidualization.

OBJECTIVE AND RATIONALE

This review summarizes our current knowledge on the known pathophysiological roles of BMPs and their underlying molecular mechanisms in regulating human endometrial proliferation and decidualization, with the goal of promoting the development of innovative strategies for diagnosing, treating and preventing infertility and adverse pregnancy complications associated with dysregulated human endometrial remodeling.

SEARCH METHODS

A literature search for original articles published up to June 2023 was conducted in the PubMed, MEDLINE, and Google Scholar databases, identifying studies on the roles of BMPs in endometrial remodeling during the human menstrual cycle and pregnancy. Articles identified were restricted to English language full-text papers.

OUTCOMES

BMP ligands and receptors and their transduction molecules are expressed in the endometrium and at the maternal-fetal interface. Along with emerging technologies such as tissue microarrays, 3D organoid cultures and advanced single-cell transcriptomics, and given the clinical availability of recombinant human proteins and ongoing pharmaceutical development, it is now clear that BMPs exert multiple roles in regulating human endometrial remodeling and that these biomolecules (and their receptors) can be targeted for diagnostic and therapeutic purposes. Moreover, dysregulation of these ligands, their receptors, or signaling determinants can impact endometrial remodeling, contributing to infertility or pregnancy-related complications (e.g. preeclampsia and miscarriage).

WIDER IMPLICATIONS

Although further clinical trials are needed, recent advancements in the development of recombinant BMP ligands, synthetic BMP inhibitors, receptor antagonists, BMP ligand sequestration tools, and gene therapies have underscored the BMPs as candidate diagnostic biomarkers and positioned the BMP signaling pathway as a promising therapeutic target for addressing infertility and pregnancy complications related to dysregulated human endometrial remodeling.

Effect of endometrial biopsy method on ribonucleic acid quality and gene expression analysis in patients with leiomyoma

Objective

To compare ribonucleic acid (RNA) quantity and purity in tissue collected with different endometrial sampling methods to establish the optimal tool for use in endometrial gene expression studies.

Design

Observational study.

Setting

University hospital.

Patients

Fourteen patients with submucosal leiomyomas.

Interventions

Unguided biopsies were obtained using a low-pressure suction device before hysteroscopy from 14 patients with submucosal leiomyomas followed by guided biopsy with a resectoscope loop. Fifty-seven samples were collected: 25 obtained using a suction device and 32 with a loop.

Main Outcome Measures

Total biopsy weight, RNA purity, and RNA yield for each collection method. After complementary deoxyribonucleic acid synthesis, HOXA10 expression was measured by quantitative polymerase chain reaction in the endometrium overlying and remote from the leiomyoma, as similar expression throughout the cavity was a prerequisite for the use of unguided biopsy method.

Results

The median weight of the samples was significantly larger when obtained with the low-pressure suction device than with the resectoscope loop (153 vs. 20 mg). The RNA yield was similar (suction curette, 1,625 ng/mg; resectoscope loop, 1,779 ng/mg). The A260-to-A280 ratio was satisfactory for 94.7 % of the samples, with no difference between the groups. The endometrial expression of HOXA10 was similar in areas overlying the leiomyoma compared with that in remote endometrial sites (2-ΔCt = 0.0224 vs. 0.0225).

Conclusions

Low-pressure endometrial suction devices provide tissue samples with acceptable RNA purity and quantity for gene expression studies. The expression of HOXA10 did not differ between endometrial sampling sites even in the presence of leiomyomas.

Impaired bone morphogenetic protein (BMP) signaling pathways disrupt decidualization in endometriosis

Endometriosis is linked to increased infertility and pregnancy complications due to defective endometrial decidualization. We hypothesized that identification of altered signaling pathways during decidualization could identify the underlying cause of infertility and pregnancy complications. Our study reveals that transforming growth factor β (TGFβ) pathways are impaired in the endometrium of individuals with endometriosis, leading to defective decidualization. Through detailed transcriptomic analyses, we discovered abnormalities in TGFβ signaling pathways and key regulators, such as SMAD4, in the endometrium of affected individuals. We also observed compromised activity of bone morphogenetic proteins (BMP), a subset of the TGFβ family, that control endometrial receptivity. Using 3-dimensional models of endometrial stromal and epithelial assembloids, we showed that exogenous BMP2 improved decidual marker expression in individuals with endometriosis. Our findings reveal dysfunction of BMP/SMAD signaling in the endometrium of individuals with endometriosis, explaining decidualization defects and subsequent pregnancy complications in these individuals.

COVID-19 and abnormal uterine bleeding: potential associations and mechanisms

The impact of COVID-19 on menstruation has received a high level of public and media interest. Despite this, uncertainty exists about the advice that women and people who menstruate should receive in relation to the expected impact of SARS-CoV-2 infection, long COVID or COVID-19 vaccination on menstruation. Furthermore, the mechanisms leading to these reported menstrual changes are poorly understood. This review evaluates the published literature on COVID-19 and its impact on menstrual bleeding, discussing the strengths and limitations of these studies. We present evidence consistent with SARS-CoV-2 infection and long COVID having an association with changes in menstrual bleeding parameters and that the impact of COVID vaccination on menstruation appears less significant. An overview of menstrual physiology and known causes of abnormal uterine bleeding (AUB) is provided before discussing potential mechanisms which may underpin the menstrual disturbance reported with COVID-19, highlighting areas for future scientific study. Finally, consideration is given to the effect that menstruation may have on COVID-19, including the impact of the ovarian sex hormones on acute COVID-19 severity and susceptibility and reported variation in long COVID symptoms across the menstrual cycle. Understanding the current evidence and addressing gaps in our knowledge in this area are essential to inform public health policy, direct the treatment of menstrual disturbance and facilitate development of new therapies, which may reduce the severity of COVID-19 and improve quality of life for those experiencing long COVID.

Unveiling the Role of Endometrial CD-138: A Comprehensive Review on Its Significance in Infertility and Early Pregnancy

This review comprehensively examines the role of endometrial CD-138 (syndecan-1) in the context of infertility and early pregnancy. The endometrium, a dynamic tissue responsive to hormonal cues, plays a central role in fertility, and understanding the molecular intricacies governing its function is crucial. CD-138, a cell surface proteoglycan, emerges as a critical player expressed by various endometrial cell types. Our exploration encompasses a brief overview of the endometrium, introducing CD-138 as a significant molecular entity. The rationale for the review underscores the importance of elucidating endometrial factors in fertility and addresses existing knowledge gaps related to CD-138. Throughout the review, we unravel the multifaceted nature of CD-138 and its involvement in infertility, highlighting its potential as a diagnostic marker. Furthermore, insights into CD-138's role during early pregnancy, including trophoblast-endothelial interactions, are discussed. In conclusion, the findings underscore the clinical implications of CD-138, suggesting its utility in diagnostics and offering prospects for targeted therapeutic interventions. The identified knowledge gaps propel future research directions, promising to deepen our understanding of this enigmatic molecule and its transformative potential in reproductive medicine.

Reproductive physiology with emphasis on endometrial cycles of woolly and uakari monkeys-A literature review

The ability of a species to withstand human impact depends on its life history characteristics, including social, ranging, and reproductive activity. The genera Lagothrix and Cacajao are more susceptible to anthropic action than small-sized primates due to their slower life histories, more restricted geographical ranges, and lower population densities. This narrative literature review aimed to gather scientific information available from the last 60 years on the reproductive biology of females of the genera Lagothrix and Cacajao. Most studies on the genus Lagothrix, mainly focused on L. lagothricha and L. l. poeppigii, present important advances on reproductive strategies, reproductive productivity, functional morphology and physiology, including seasonality, sexual cycle, gestation and fetal development in captive and free-living populations. Contrary, there is much less known about the reproductive biology of the genus Cacajao, with studies on free-living C. calvus and C. melanocephalus highlighting reproductive behavior, and basic description of the sexual cycle, gestation, and lactation. Unfortunately, the morphology of the female genital organs is only described in C. calvus, and there is still scarce information about the menstrual activity and the placenta. This literature review encourages primatologists, morphophysiologists, reproductive specialists, and ecologists to conduct comprehensive studies of these species to better understand the gaps in knowledge about reproduction, their relationship with their environment, including climatic and social variables. Understanding the integrative reproductive biology of these species will be a clue for improving the assessment of the resilience capacity of free-living populations and, consequently, establishing more appropriate management programs, and for the development of ex situ management techniques for the conservation of the species.

What do we know about why women bleed and what do we not know?

Women or people with a uterus are vulnerable to both normal and abnormal bleeding. During the reproductive years, the uterus is prepared physiologically to accept an embryo and support its growth and development during pregnancy, or in the absence of implantation of an embryo, recycle through the process of menstruation and accept an embryo a month or so later. If fertilization takes place and an embryo or embryos implant in the uterus, the fetal trophoblast, or outer cell layer of the embryo, invades and dilates the maternal spiral arteries and forms the placenta. No matter when in gestation a pregnancy ends, at the conclusion of pregnancy, the placenta should separate from the wall of the uterus and be expelled. Abnormal bleeding occurs during pregnancy or after delivery when the normal uteroplacental interface has not been established or is interrupted; during miscarriage; during ectopic pregnancy; during premature separation of the placenta; or during postpartum hemorrhage. Heavy menstrual bleeding, a subset of abnormal menstrual bleeding, can be quantitatively defined as >80 mL of blood loss per cycle. Unlike postpartum hemorrhage, heavy menstrual bleeding is significantly associated with an underlying bleeding disorder. While there is other reproductive tract bleeding in women, notably bleeding at the time of ovulation or with a life-threatening ruptured ectopic pregnancy, the unique bleeding that women experience is predominantly uterine in origin. Many of the unique aspects of uterine hemostasis, however, remain unknown.

Extensive heterogeneity in the expression of steroid receptors in superficial peritoneal endometriotic lesions

RESEARCH QUESTION

Is the expression of steroid hormone receptors (oestrogen receptor-α and progesterone receptor A/B) and proliferative markers (Bcl-2 and Ki67) uniform among superficial peritoneal endometriotic lesions?

DESIGN

A retrospective cohort study of 24 patients with surgically and histologically confirmed endometriosis. Immunofluorescence was used to determine the proportion of oestrogen receptor-α (ERα), progesterone receptor A/B, Bcl-2 and Ki67 positive cells in 271 endometriotic lesions (defined as endometriotic gland profile/s within an individual region of CD10 stromal immunostaining from a single biopsy) from 67 endometriotic biopsies from 24 patients. Data were analysed to examine associations related to menstrual cycle stage, lesion location and gland morphology.

RESULTS

Oestrogen receptor-α and progesterone receptor A/B expression in superficial peritoneal endometriotic lesions was extremely heterogeneous. Bcl-2 immunostaining in endometriotic lesions was also variable, whereas Ki67 immunostaining was minimal. Menstrual cycle stage associations were limited in steroid hormone receptor and Bcl-2 expression in lesions. Patterns in progesterone receptor A/B and Bcl-2 immunostaining were associated with lesion location. Bcl-2 was differentially expressed, based on lesion gland morphology.

CONCLUSIONS

These data demonstrate considerable diversity in the expression of steroid hormone receptors and Bcl-2 between lesions, even within an individual patient.

Impaired receptivity of thin endometrium: therapeutic potential of mesenchymal stem cells

The endometrium is a resilient and highly dynamic tissue, undergoing cyclic renewal in preparation for embryo implantation. Cyclic endometrial regeneration depends on the intact function of several cell types, including parenchymal, endothelial, and immune cells, as well as adult stem cells that can arise from endometrial or extrauterine sources. The ability of the endometrium to undergo rapid, repeated regeneration without scarring is unique to this tissue. However, if this tissue renewal process is disrupted or dysfunctional, women may present clinically with infertility due to endometrial scarring or persistent atrophic/thin endometrium. Such disorders are rate-limiting in the treatment of female infertility and in the success of in vitro fertilization because of a dearth of treatment options specifically targeting the endometrium. A growing number of studies have explored the potential of adult stem cells, including mesenchymal stem cells (MSCs), to treat women with disorders of endometrial regeneration. MSCs are multipotent adult stem cells with capacity to differentiate into cells such as adipocytes, chondrocytes, and osteoblasts. In addition to their differentiation capacity, MSCs migrate toward injured sites where they secrete bioactive factors (e.g. cytokines, chemokines, growth factors, proteins and extracellular vesicles) to aid in tissue repair. These factors modulate biological processes critical for tissue regeneration, such as angiogenesis, cell migration and immunomodulation. The MSC secretome has therefore attracted significant attention for its therapeutic potential. In the uterus, studies utilizing rodent models and limited human trials have shown a potential benefit of MSCs and the MSC secretome in treatment of endometrial infertility. This review will explore the potential of MSCs to treat women with impaired endometrial receptivity due to a thin endometrium or endometrial scarring. We will provide context supporting leveraging MSCs for this purpose by including a review of mechanisms by which the MSC secretome promotes regeneration and repair of nonreproductive tissues.

Theoretical Studies on the Quantitative Structure-Toxicity Relationship of Polychlorinated Biphenyl Congeners Reveal High Affinity Binding to Multiple Human Nuclear Receptors

Polychlorinated biphenyls (PCBs) are organic chemicals consisting of a biphenyl structure substituted with one to ten chlorine atoms, with 209 congeners depending on the number and position of the chlorine atoms. PCBs are widely known to be endocrine-disrupting chemicals (EDCs) and have been found to be involved in several diseases/disorders. This study takes various molecular descriptors of these PCBs (e.g., molecular weight) and toxicity endpoints as molecular activities, investigating the possibility of correlations via the quantitative structure-toxicity relationship (QSTR). This study then focuses on molecular docking and dynamics to investigate the docking behavior of the strongest-binding PCBs to nuclear receptors and compares these to the docking behavior of their natural ligands. Nuclear receptors are a family of transcription factors activated by steroid hormones, and they have been investigated to consider the impact of PCBs on humans in this context. It has been observed that the docking affinity of PCBs is comparable to that of the natural ligands, but they are inferior in terms of stability and interacting forces, as shown by the RMSD and total energy values. However, it is noted that most nuclear receptors respond to PCBs similarly to how they respond to their natural ligands-as shown in the RMSF plots-the most similar of which are seen in the ER, THR-β, and RAR-α. However, this study is performed purely in silico and will need experimental verification for validation.

Proposal for targeted, neo-evolutionary-oriented, secondary prevention of early-onset endometriosis and adenomyosis. Part I: pathogenic aspects

The potential for repeated ovulation and menstruation is thought to have provided a Darwinian advantage during the Palaeolithic. Reproductive conditions remained relatively stable until the pre-industrial era, characterized by late menarche, very young age at first birth, multiple pregnancies, and prolonged periods of lactational amenorrhoea. For hundreds of thousands of years, menstruators experienced few ovulatory cycles, even though they were genetically adapted to ovulate and menstruate every month. In the post-industrial era, the age at menarche gradually declined, the age at first birth progressively increased, and breastfeeding became optional and often of short duration. This created a mismatch between genetic adaptation and socio-environmental evolution, so that what was initially a probable reproductive advantage subsequently contributed to increased susceptibility to diseases associated with lifetime oestrogen exposure, such as ovarian, endometrial and breast cancer and, hypothetically, also those associated with the number of ovulatory menstruations, such as endometriosis and adenomyosis. The incidence of endometriosis shows a steep and progressive increase around the age of 25 years, but given the consistently reported delay in diagnosis, the actual incidence curve should be shifted to the left, supporting the possibility that the disease has its roots in adolescence. This raises the question of whether, from an evolutionary point of view, anovulation and amenorrhoea should not still be considered the physiological state, especially in the postmenarchal period. However, an increase in the frequency of endometriosis in recent decades has not been demonstrated, although this deserves further epidemiological investigation. In addition, as endometriosis occurs in a minority of individuals exposed to retrograde menstruation, other important pathogenic factors should be scrutinised. Research should be resumed to explore in more detail the transtubal reflux of not only blood, but also endometrial cells, and whether they are systematically present in the peritoneal fluid after menstruation. If repetitive ovulatory menstruation during the early reproductive years is shown to increase the risk of endometriosis and adenomyosis development and progression in susceptible individuals, hormonal interventions could be used as secondary prevention in symptomatic adolescents.

Endometrial protein expression and phosphorylation landscape decipher aberrant insulin and mTOR signalling in patients with recurrent pregnancy loss

RESEARCH QUESTION

What are the proteomic and phosphoproteomic differences between the endometrium of women with recurrent pregnancy loss (RPL) and the endometrium of healthy control women during the proliferative and secretory phases of the menstrual cycle?

DESIGN

In total, 54 endometrial samples were collected during the proliferative and secretory phases from women with RPL (n = 28) and healthy controls (n = 26). Comprehensive proteomic and phosphoproteomic analyses were conducted using label-free liquid chromatography-tandem mass spectrometry (n = 44), and verified through Western blotting (n = 10). Three comparison groups were established: total RPL endometrium versus total control endometrium; RPL proliferative endometrium versus control proliferative endometrium; and RPL secretory endometrium versus control secretory endometrium.

RESULTS

Differentially expressed proteins and differentially phosphorylated proteins were identified in the three comparison groups. Combining pathway enrichment, network analysis and soft clustering analysis, the insulin/cyclic nucleotide signalling pathway and AMPK/mTOR signalling pathway were identified as the major contributors to the aberration of RPL endometrium. Western blotting verified altered expression of four proteins: cAMP-dependent protein kinase type I-β regulatory subunit, adenylate cyclase type 3, 5'-AMP-activated protein kinase catalytic subunit α-2 and phosphatidate phosphatase LPIN2.

CONCLUSIONS

This exploratory study provides insights into the differentiated protein expression and phosphorylation profiles of the endometrium of women with RPL in both the proliferative and sectretory phases of the menstrual cycle. The results highlight potential proteins associated with the pathogenesis of RPL that may serve as potential indicators for RPL. The findings contribute to the identification of potential targets for RPL treatment as well as its pathogenesis.

Associations Among Menstrual Cycle Length, Coronavirus Disease 2019 (COVID-19), and Vaccination

OBJECTIVE

To assess whether coronavirus disease 2019 (COVID-19) is associated with menstrual cycle length changes and, if so, how that compares with those undergoing vaccination or no event (control).

METHODS

We conducted a retrospective cohort analysis in which we analyzed prospectively tracked cycle-length data from users of a period tracker application who also responded to a survey regarding COVID-19 symptoms and vaccination. We restricted our sample to users aged 16-45 years, with normal cycle lengths (24-38 days) and regular tracking behavior during the five cycles around COVID-19 symptoms or vaccination or a similar time period for those experiencing no event (control group). We calculated the within-user change in cycle length (days) from the three consecutive cycles preevent average (either vaccination, disease, or neither; cycles 1-3) to the event (cycle 4) and postevent (cycle 5) cycles. We used mixed-effects models to estimate the age- and country-adjusted difference in change in cycle length across the groups.

RESULTS

We included 6,514 users from 110 countries representing 32,570 cycles (COVID-19 symptoms: 1,450; COVID-19 vaccination: 4,643; control: 421). The COVID-19 cohort experienced a 1.45-day adjusted increase in cycle length during cycle 4 (COVID-19) compared with their three preevent cycles (95% CI 0.86-2.04). The vaccinated group experienced a 1.14-day adjusted increase in cycle length during cycle 4 (COVID-19 vaccine) compared with their preevent average (95% CI 0.60-1.69). The control group (neither vaccine nor disease) experienced a 0.68-day decrease (95% CI -1.18 to -0.19) in a similar time period. Post hoc tests showed no significant differences in the magnitude of changes between the COVID-19 and vaccination cohorts. In both cohorts, cycle length changes disappeared in the postevent cycle.

CONCLUSION

Experiencing COVID-19 is associated with a small change in cycle length similar to COVID-19 vaccination. These changes resolve quickly within the next cycle.

Detection and quantification of various microplastics in human endometrium based on laser direct infrared spectroscopy

The pollution of microplastics (MPs) has received widespread attention with the increasing usage of plastics in recent years. MPs could enter the human body and exist in the circulatory system. Endometrium, with rich blood vessels, acts as an essential role in human health and female fertility. However, there is no study reporting the MPs exposure in human endometrium. We collected the endometrium samples to detect the presence of MPs qualitatively and quantitatively via laser direct infrared. We found that there was a total of 13 types of MPs existing in the collected samples, among which 6 special types of MPs were with both high abundance and high detection rate. The abundance of these MPs ranged from 0 to 117 particles/100 mg, with a median abundance of 21 particles/100 mg. Most detected MPs, accounting for 88.35 %, were in small size (20-100 μm). Among small-size MPs, ethylene-acrylic acid copolymer ranked first while polyethylene accounted for the largest proportion among large-size MPs (100-500 μm). Correlation analysis indicated there was no significant relationship between age and MP abundance or BMI and MP abundance. We also designed a questionnaire to investigate lifestyle and daily habits, aiming at revealing the potential relationship between MP exposure and living habits. We discovered that some drinking habits and chewing gum were significantly correlated with a higher level of MP exposure. For the first time, we identified the presence of MPs in human endometrium and clarified the potential connections between MP exposure and lifestyle. Further studies are still necessary to explore more underlying information.

Nanostrategy of Targeting at Embryonic Trophoblast Cells Using CuO Nanoparticles for Female Contraception

Effective contraceptives have been comprehensively adopted by women to prevent the negative consequences of unintended pregnancy for women, families, and societies. With great contributions of traditional hormonal drugs and intrauterine devices (IUDs) to effective female contraception by inhibiting ovulation and deactivating sperm, their long-standing side effects on hormonal homeostasis and reproductive organs for females remain concerns. Herein, we proposed a nanostrategy for female contraceptives, inducing embryonic trophoblast cell death using nanoparticles to prevent embryo implantation. Cupric oxide nanoparticles (CuO NPs) were adopted in this work to verify the feasibility of the nanostrategy and its contraceptive efficacy. We carried out the in vitro assessment on the interaction of CuO NPs with trophoblast cells using the HTR8/SVneo cell line. The results showed that the CuO NPs were able to be preferably uptaken into cells and induced cell damage via a variety of pathways including oxidative stress, mitochondrial damage, DNA damage, and cell cycle arrest to induce cell death of apoptosis, ferroptosis, and cuproptosis. Moreover, the key regulatory processes and the key genes for cell damage and cell death caused by CuO NPs were revealed by RNA-Seq. We also conducted in vivo experiments using a rat model to examine the contraceptive efficacy of both the bare CuO NPs and the CuO/thermosensitive hydrogel nanocomposite. The results demonstrated that the CuO NPs were highly effective for contraception. There was no sign of disrupting the homeostasis of copper and hormone, or causing inflammation and organ damage in vivo. In all, this nanostrategy exhibited huge potential for contraceptive development with high biosafety, efficacy, clinical translation, nonhormonal style, and on-demand for women.

Exploring distinct properties of endometrial stem cells through advanced single-cell analysis platforms

The endometrium is a dynamic tissue that undergoes cyclic changes in response to ovarian hormones during the menstrual cycle. These changes are crucial for pregnancy establishment and maintenance. Endometrial stem cells play a pivotal role in endometrial regeneration and repair by differentiating into various cell types within the endometrium. However, their involvement in endometrial disorders such as endometriosis, infertility, and endometrial cancer is still not fully understood yet. Traditional bulk sequencing methods have limitations in capturing heterogeneity and complexity of endometrial stem cell populations. To overcome these limitations, recent single-cell analysis techniques, including single-cell RNA sequencing (scRNA-Seq), single-cell ATAC sequencing (scATAC-Seq), and spatial transcriptomics, have emerged as valuable tools for studying endometrial stem cells. In this review, although there are still many technical limitations that require improvement, we will summarize the current state-of-the-art single-cell analysis techniques for endometrial stem cells and explore their relevance to related diseases. We will discuss studies utilizing various single-cell analysis platforms to identify and characterize distinct endometrial stem cell populations and investigate their dynamic changes in gene expression and epigenetic patterns during menstrual cycle and differentiation processes. These techniques enable the identification of rare cell populations, capture heterogeneity of cell populations within the endometrium, and provide potential targets for more effective therapies.

Effects of SARS-CoV-2 Vaccination on Menstrual Cycle: An Italian Survey-Based Study

Vaccination against SARS-CoV-2 has played a critical role in controlling the spread of the pandemic. The main side effects of SARS-CoV-2 vaccination include fever and fatigue; however, the potential impacts on menstrual cycles are to be determined. Given the limited number of studies suggesting menstrual changes post vaccination, this study investigates the correlation between COVID-19 vaccines and menstrual cycle changes in fertile-aged Italian women. A questionnaire was distributed from 1 October to 31 November 2022, focusing on menstrual rhythm and flow changes post vaccination. The analysis involved 471 participants. The study observed a shift from a regular to an irregular menstrual rhythm (p < 0.001), and changes in menstrual duration (p = 0.008 and p < 0.001 for first and second doses, respectively) and flow volume (p < 0.001). Most patients with irregular rhythms were vaccinated in the proliferative phase of their cycle. Within six months post vaccination, 74.2% of women with irregular post-vaccination rhythms reported a return to normality. These findings indicate primarily transient menstrual changes following mRNA COVID-19 vaccination, suggesting the vaccines' safety for women of reproductive age.

Aspects of human uterine creatine metabolism during the menstrual cycle and at term pregnancy†

Creatine metabolism likely contributes to energy homeostasis in the human uterus, but whether this organ synthesizes creatine and whether creatine metabolism is adjusted throughout the menstrual cycle and with pregnancy are largely unknown. This study determined endometrial protein expression of creatine-synthesizing enzymes arginine:glycine amidinotransferase (AGAT) and guanidinoacetate methyltransferase (GAMT), creatine kinase (CKBB), and the creatine transporter (SLC6A8) throughout the menstrual cycle in fertile and primary infertile women. It also characterized creatine metabolism at term pregnancy, measuring aspects of creatine metabolism in myometrial and decidual tissue. In endometrial samples, AGAT, GAMT, SLC6A8, and CKBB were expressed in glandular and luminal epithelial cells. Except for SLC6A8, the other proteins were also located in stromal cells. Irrespective of fertility, AGAT, GAMT, and SLC6A8 high-intensity immunohistochemical staining was greatest in the early secretory phase of the menstrual cycle. During the proliferative phase, staining for SLC6A8 protein was greater (P = 0.01) in the primary infertile compared with the fertile group. Both layers of the term pregnant uterus contained creatine, phosphocreatine, guanidinoacetic acid, arginine, glycine, and methionine; detectable gene and protein expression of AGAT, GAMT, CKBB, and ubiquitous mitochondrial CK (uMt-CK); and gene expression of SLC6A8. The proteins AGAT, GAMT, CKBB, and SLC6A8 were uniformly distributed in the myometrium and localized to the decidual glands. In conclusion, endometrial tissue has the capacity to produce creatine and its capacity is highest around the time of fertilization and implantation. Both layers of the term pregnant uterus also contained all the enzymatic machinery and substrates of creatine metabolism.

Peony Pollen Protects against Primary Dysmenorrhea in Mice by Inhibiting Inflammatory Response and Regulating the COX2/PGE2 Pathway

Peony pollen contains multiple nutrients and components and has been used as a traditional Chinese medicine with a long history, but the effect of the treatment of primary dysmenorrhea remains to be clarified. The aim of this study is to investigate the therapeutic effect of peony pollen on primary dysmenorrhea mice and the potential mechanism. A uterus contraction model in vitro and primary dysmenorrhea mice were used to evaluate the treatment effect of peony pollen on primary dysmenorrhea. The primary dysmenorrhea mice were treated with 62.5 mg/kg, 125 mg/kg, or 250 mg/kg of peony pollen, and the writhing response, latency period, histopathological changes in the uterus, prostaglandin E2 (PGE2) and prostaglandin F2α (PGF2α) levels, and infiltration of neutrophils and macrophages were investigated. Protein expression of interleukin 1 β (IL-1β), interleukin 6 (IL-6), NOD-like receptor thermal protein domain associated protein 3 (NLRP3), cyclooxygenase-2 (COX-2), microsomal prostaglandin-E synthase 1 (mPGEs-1), BCL2-Associated X (Bax), B-cell lymphoma-2 (BCL-2), caspase-3, and cleaved caspase-3 were detected by Western blot, and the oxidative stress related marker malondialdehyde (MDA), superoxide dismutase (SOD), glutathione peroxidase (GSH-Px), and reactive oxygen species (ROS) were evaluated. Peony pollen could attenuate spontaneous or oxytocin-induced uterus contractions in vitro. Moreover, peony pollen decreased the writhing times, prolonged the writhing latency, and reduced the pathological damage of uterine tissues. Furthermore, the inflammatory cell infiltration and the protein expression of IL-1β, IL-6, and NLRP3 were decreased. The COX-2/PGE2 pathway was inhibited; oxidative stress and apoptosis in the uterus also improved in the uterus of primary dysmenorrhea mice. Peony pollen exerts a positive effect on primary dysmenorrhea by inhibiting the inflammatory response and modulating oxidative stress and apoptosis by regulating the COX-2/PGE2 pathway.

Imaging biomarker for quantitative analysis of endometrial injury based on optical coherence tomography/ultrasound integrated imaging mode

Precise evaluation of endometrial injury is significant to clinical decision-making in gynecological disease and assisted reproductive technology. However, there is a lack of assessment methods for endometrium in vivo. In this research, we intend to develop quantitative imaging markers with optical coherence tomography (OCT)/ultrasound (US) integrated imaging system through intrauterine endoscopic imaging. OCT/US integrated imaging system was established as our previous research reported. The endometrial injury model was established and after treatment, OCT/US integrated imaging and uterus biopsy was performed to evaluate the endometrial thickness, number of superficial fold, and intrauterine area. According to the results, three quantitative indexes acquired from OCT/US image and HE staining have the same trend and have a strong relationship with the severity of the endometrial injury. Accordingly, we developed three imaging markers for quantitative analysis of endometrial injury in vivo, which provided a precise mode for endometrium evaluation in clinical practice.

Cyclical endometrial repair and regeneration: Molecular mechanisms, diseases, and therapeutic interventions

The endometrium is a unique human tissue with an extraordinary ability to undergo a hormone-regulated cycle encompassing shedding, bleeding, scarless repair, and regeneration throughout the female reproductive cycle. The cyclical repair and regeneration of the endometrium manifest as changes in endometrial epithelialization, glandular regeneration, and vascularization. The mechanisms encompass inflammation, coagulation, and fibrinolytic system balance. However, specific conditions such as endometriosis or TCRA treatment can disrupt the process of cyclical endometrial repair and regeneration. There is uncertainty about traditional clinical treatments' efficacy and side effects, and finding new therapeutic interventions is essential. Researchers have made substantial progress in the perspective of regenerative medicine toward maintaining cyclical endometrial repair and regeneration in recent years. Such progress encompasses the integration of biomaterials, tissue-engineered scaffolds, stem cell therapies, and 3D printing. This review analyzes the mechanisms, diseases, and interventions associated with cyclical endometrial repair and regeneration. The review discusses the advantages and disadvantages of the regenerative interventions currently employed in clinical practice. Additionally, it highlights the significant advantages of regenerative medicine in this domain. Finally, we review stem cells and biologics among the available interventions in regenerative medicine, providing insights into future therapeutic strategies.

Endometrial TGFβ signaling fosters early pregnancy development by remodeling the fetomaternal interface

The endometrium is a unique and highly regenerative tissue with crucial roles during the reproductive lifespan of a woman. As the first site of contact between mother and embryo, the endometrium, and its critical processes of decidualization and immune cell recruitment, play a leading role in the establishment of pregnancy, embryonic development, and reproductive capacity. These integral processes are achieved by the concerted actions of steroid hormones and a myriad of growth factor signaling pathways. This review focuses on the roles of the transforming growth factor β (TGFβ) pathway in the endometrium during the earliest stages of pregnancy through the lens of immune cell regulation and function. We discuss how key ligands in the TGFβ family signal through downstream SMAD transcription factors and ultimately remodel the endometrium into a state suitable for embryo implantation and development. We also focus on the key roles of the TGFβ signaling pathway in recruiting uterine natural killer cells and their collective remodeling of the decidua and spiral arteries. By providing key details about immune cell populations and TGFβ signaling within the endometrium, it is our goal to shed light on the intricate remodeling that is required to achieve a successful pregnancy.

Why Does Your Uterus Become Malignant? The Impact of the Microbiome on Endometrial Carcinogenesis

The aim of this review was to describe the uterine microbiome composition that has been analyzed so far and describe potential pathways in the carcinogenesis of the endometrium. The microbiome in the uterine environment is involved in apoptosis and proliferation during the menstruation cycle, pregnancy maintenance, and immune system support. However, bacteria in the uterus could stimulate inflammation, which when chronic results in malignancy. An altered gut microbiota initiates an inflammatory response through microorganism-associated molecular patterns, which leads to intensified steroidogenesis in the ovaries and cancers. Moreover, intestinal bacteria secreting the enzyme β-glucuronidase may increase the level of circulating estrogen and, as a result, be influential in gynecological cancers. Both the uterine and the gut microbiota play a pivotal role in immune modulation, which is why there is a demand for further investigation from both the diagnostic and the therapeutic perspectives.

A cell abundance analysis based on efficient PAM clustering for a better understanding of the dynamics of endometrial remodelling

BACKGROUND

Single-cell RNA sequencing (scRNA-seq) is a powerful tool for investigating cell abundance changes during tissue regeneration and remodeling processes. Differential cell abundance supports the initial clustering of all cells; then, the number of cells per cluster and sample are evaluated, and the dependence of these counts concerning the phenotypic covariates of the samples is studied. Analysis heavily depends on the clustering method. Partitioning Around Medoids (PAM or k-medoids) represents a well-established clustering procedure that leverages the downstream interpretation of clusters by pinpointing real individuals in the dataset as cluster centers (medoids) without reducing dimensions. Of note, PAM suffers from high computational costs and memory requirements.

RESULTS

This paper proposes a method for differential abundance analysis using PAM as a clustering method and negative binomial regression as a statistical model to relate covariates to cluster/cell counts. We used this approach to study the differential cell abundance of human endometrial cell types throughout the natural secretory phase of the menstrual cycle. We developed a new R package -scellpam-, that incorporates an efficient parallel C++ implementation of PAM, and applied this package in this study. We compared the PAM-BS clustering method with other methods and evaluated both the computational aspects of its implementation and the quality of the classifications obtained using distinct published datasets with known subpopulations that demonstrate promising results.

CONCLUSIONS

The implementation of PAM-BS, included in the scellpam package, exhibits robust performance in terms of speed and memory usage compared to other related methods. PAM allowed quick and robust clustering of sets of cells with a size ranging from 70,000 to 300,000 cells. https://cran.r-project.org/web/packages/scellpam/index.html . Finally, our approach provides important new insights into the transient subpopulations associated with the fertile time frame when applied to the study of changes in the human endometrium during the secretory phase of the menstrual cycle.

A case of delayed postoperative bleeding after excision of endometrial polyp using resectoscope in an infertile woman with von Willebrand disease:a case report and literature review

Von Willebrand disease (VWD) is a bleeding disorder caused by a congenital quantitative reduction, deficiency, or qualitative abnormality of the von Willebrand factor (VWF). Here, we report a case of delayed postoperative bleeding in an infertile woman with endometrial polyps complicated by VWD. The patient was a 39-year-old infertile woman with type 2A VWD. At 38 years of age, she was referred to our hospital for infertility and heavy menstrual bleeding. Hysteroscopy revealed a 15-mm polyp lesion in the uterus. The patient was scheduled for transcervical resection (TCR) of the endometrial polyp. Gonadotropin-releasing hormone agonists were preoperatively administered to prevent menstruation. The VWF-containing concentrate was administered for 3 days according to guidelines. The patient was discharged on postoperative day 3 after confirming the absence of uterine bleeding. Uterine bleeding began on postoperative day 6. The patient was readmitted on postoperative day 7 and treated with VWF-containing concentrate for 5 days, after which hemostasis was confirmed. TCR surgery for endometrial lesions is classified as a minor surgery, and guidelines recommend short-term VWF-containing concentrate replacement. However, it should be kept in mind that only short-term VWF-containing concentrate replacement may cause rebleeding postoperatively.

Epigenetic Dysregulation in Endometriosis: Implications for Pathophysiology and Therapeutics

Endometriosis is a prevalent gynecological condition associated with pelvic pain and infertility. Despite more than a century of research, the etiology of endometriosis still eludes scientific consensus. This lack of clarity has resulted in suboptimal prevention, diagnosis, and treatment options. Evidence of genetic contributors to endometriosis is interesting but limited; however, significant progress has been made in recent years in identifying an epigenetic role in the pathogenesis of endometriosis through clinical studies, in vitro cell culture experiments, and in vivo animal models. The predominant findings include endometriosis-related differential expression of DNA methyltransferases and demethylases, histone deacetylases, methyltransferases, and demethylases, and regulators of chromatin architecture. There is also an emerging role for miRNAs in controlling epigenetic regulators in the endometrium and endometriosis. Changes in these epigenetic regulators result in differential chromatin organization and DNA methylation, with consequences for gene expression independent of a genetic sequence. Epigenetically altered expression of genes related to steroid hormone production and signaling, immune regulation, and endometrial cell identity and function have all been identified and appear to play into the pathophysiological mechanisms of endometriosis and resulting infertility. This review summarizes and critically discusses early seminal findings, the ever-growing recent evidence of epigenetic contributions to the pathophysiology of endometriosis, and implications for proposed epigenetically targeted therapeutics.

Endometrial receptivity in women of advanced age: an underrated factor in infertility

BACKGROUND

Modern lifestyle has led to an increase in the age at conception. Advanced age is one of the critical risk factors for female-related infertility. It is well known that maternal age positively correlates with the deterioration of oocyte quality and chromosomal abnormalities in oocytes and embryos. The effect of age on endometrial function may be an equally important factor influencing implantation rate, pregnancy rate, and overall female fertility. However, there are only a few published studies on this topic, suggesting that this area has been under-explored. Improving our knowledge of endometrial aging from the biological (cellular, molecular, histological) and clinical perspectives would broaden our understanding of the risks of age-related female infertility.

OBJECTIVE AND RATIONALE

The objective of this narrative review is to critically evaluate the existing literature on endometrial aging with a focus on synthesizing the evidence for the impact of endometrial aging on conception and pregnancy success. This would provide insights into existing gaps in the clinical application of research findings and promote the development of treatment options in this field.

SEARCH METHODS

The review was prepared using PubMed (Medline) until February 2023 with the keywords such as 'endometrial aging', 'receptivity', 'decidualization', 'hormone', 'senescence', 'cellular', 'molecular', 'methylation', 'biological age', 'epigenetic', 'oocyte recipient', 'oocyte donation', 'embryo transfer', and 'pregnancy rate'. Articles in a language other than English were excluded.

OUTCOMES

In the aging endometrium, alterations occur at the molecular, cellular, and histological levels suggesting that aging has a negative effect on endometrial biology and may impair endometrial receptivity. Additionally, advanced age influences cellular senescence, which plays an important role during the initial phase of implantation and is a major obstacle in the development of suitable senolytic agents for endometrial aging. Aging is also accountable for chronic conditions associated with inflammaging, which eventually can lead to increased pro-inflammation and tissue fibrosis. Furthermore, advanced age influences epigenetic regulation in the endometrium, thus altering the relation between its epigenetic and chronological age. The studies in oocyte donation cycles to determine the effect of age on endometrial receptivity with respect to the rates of implantation, clinical pregnancy, miscarriage, and live birth have revealed contradictory inferences indicating the need for future research on the mechanisms and corresponding causal effects of women's age on endometrial receptivity.

WIDER IMPLICATIONS

Increasing age can be accountable for female infertility and IVF failures. Based on the complied observations and synthesized conclusions in this review, advanced age has been shown to have a negative impact on endometrial functioning. This information can provide recommendations for future research focusing on molecular mechanisms of age-related cellular senescence, cellular composition, and transcriptomic changes in relation to endometrial aging. Additionally, further prospective research is needed to explore newly emerging therapeutic options, such as the senolytic agents that can target endometrial aging without affecting decidualization. Moreover, clinical trial protocols, focusing on oocyte donation cycles, would be beneficial in understanding the direct clinical implications of endometrial aging on pregnancy outcomes.

The pathophysiological role of estrogens in the initial stages of pregnancy: molecular mechanisms and clinical implications for pregnancy outcome from the periconceptional period to end of the first trimester

BACKGROUND

Estrogens regulate disparate female physiological processes, thus ensuring reproduction. Altered estrogen levels and signaling have been associated with increased risks of pregnancy failure and complications, including hypertensive disorders and low birthweight babies. However, the role of estrogens in the periconceptional period and early pregnancy is still understudied.

OBJECTIVE AND RATIONALE

This review aims to summarize the current evidence on the role of maternal estrogens during the periconceptional period and the first trimester of pregnancies conceived naturally and following ART. Detailed molecular mechanisms and related clinical impacts are extensively described.

SEARCH METHODS

Data for this narrative review were independently identified by seven researchers on Pubmed and Embase databases. The following keywords were selected: 'estrogens' OR 'estrogen level(s)' OR 'serum estradiol' OR 'estradiol/estrogen concentration', AND 'early pregnancy' OR 'first trimester of pregnancy' OR 'preconceptional period' OR 'ART' OR 'In Vitro Fertilization (IVF)' OR 'Embryo Transfer' OR 'Frozen Embryo Transfer' OR 'oocyte donation' OR 'egg donation' OR 'miscarriage' OR 'pregnancy outcome' OR 'endometrium'.

OUTCOMES

During the periconceptional period (defined here as the critical time window starting 1 month before conception), estrogens play a crucial role in endometrial receptivity, through the activation of paracrine/autocrine signaling. A derailed estrogenic milieu within this period seems to be detrimental both in natural and ART-conceived pregnancies. Low estrogen levels are associated with non-conception cycles in natural pregnancies. On the other hand, excessive supraphysiologic estrogen concentrations at time of the LH peak correlate with lower live birth rates and higher risks of pregnancy complications. In early pregnancy, estrogen plays a massive role in placentation mainly by modulating angiogenic factor expression-and in the development of an immune-tolerant uterine micro-environment by remodeling the function of uterine natural killer and T-helper cells. Lower estrogen levels are thought to trigger abnormal placentation in naturally conceived pregnancies, whereas an estrogen excess seems to worsen pregnancy development and outcomes.

WIDER IMPLICATIONS

Most current evidence available endorses a relation between periconceptional and first trimester estrogen levels and pregnancy outcomes, further depicting an optimal concentration range to optimize pregnancy success. However, how estrogens co-operate with other factors in order to maintain a fine balance between local tolerance towards the developing fetus and immune responses to pathogens remains elusive. Further studies are highly warranted, also aiming to identify the determinants of estrogen response and biomarkers for personalized estrogen administration regimens in ART.

Upregulated RPA2 in endometrial tissues of repeated implantation failure patients impairs the endometrial decidualization

PURPOSE

To investigate the expression and underlying mechanism of RPA2 in endometrium of patients with repeated implantation failure (RIF).

METHODS

In this study, we retrieved the expression profiles from GEO databases and filtered the differentially expressed genes between RIF and the fertile control group. Ultimately, RPA2 was confirmed as a target gene. RPA2 expression in endometrial tissues of RIF patients, the control group, and different phases was detected by RT-qPCR, immunohistochemistry, and Western blotting. The role of RPA2 in endometrial decidualization was performed by in vitro decidualization inducing by 8-Br-cAMP and MPA. Furthermore, RT-qPCR was used to detect changes in the decidual biomarkers after transfection of RPA2 overexpression vector in human endometrium stromal cell (HESC).

RESULTS

RPA2 was significantly upregulated in the mid-secretory endometrium of patients with RIF. As a proliferation-related gene, RPA2 was obviously higher expressed at proliferative phase during the normal menstrual cycles. Moreover, the downregulation of RPA2 was discovered during decidualization of HESC. Furthermore, RPA2 overexpression impaired decidualization by inhibiting the expression of prolactin (PRL) and insulin-like growth factor-binding protein 1 (IGFBP1).

CONCLUSIONS

Our finding indicated that aberrant upregulation of RPA2 attenuated decidualization of HESC in RIF women and provided new potential therapeutic targets.

Chromosomal polymorphisms and susceptibility to menstrual disorders: a retrospective analysis of 24,578 women

PURPOSE

To evaluate the association between the polymorphic variants of chromosomes and menstrual disorders.

METHODS

The data from our previous retrospective, single-center cohort study were re-analyzed. Women with regular menstruation were included as controls. Women with menstrual cycle abnormalities were subgrouped according to reproductive causes. The frequency of chromosomal polymorphisms was compared between groups. Regression analysis was used to adjust for potential confounding variables.

RESULT

A total of 24,578 women composed of 8062 women with regular cycles as the control group and 16,516 women as the menstrual cycle irregularity group were included. When compared with the control group, the incidence of chromosomal polymorphisms in the total menstrual cycle irregularity group, Polycystic ovary syndrome group, and Primary ovarian insufficiency group were significantly higher (4.49% versus 5.34%, P = 0.004, 4.49% versus 5.35%, P = 0.018 and 4.49% versus 5.94%, P = 0.002, respectively). The incidences of inv(9) in the Primary ovarian insufficiency group were significantly higher than that in the control individuals (1.0% versus 1.6%, P = 0.024). Logistic regression analysis showed an effect of chromosomal polymorphisms on menstrual cycle irregularity (OR: 1.62, 95% CI: 1.234-2.187, P = 0.007; adjusted OR: 1.46, 95% CI: 1.153-1.819, P < 0.001). The result demonstrated an effect of chromosomal polymorphisms on the Primary ovarian insufficiency group (OR: 2.52, 95% CI: 1.307-5.177, P < 0.001; adjusted OR: 2.61, 95% CI: 1.371-4.605, P < 0.001).

CONCLUSION

The study suggests chromosomal polymorphisms adversely affect female menstrual cycle irregularity.

Reduced endometrial expression of histone deacetylase 3 in women with adenomyosis who complained of heavy menstrual bleeding

RESEARCH QUESTION

What role, if any, does histone deacetylase 3 (HDAC3) play in adenomyosis-associated heavy menstrual bleeding (HMB)?

DESIGN

Seventy-two women with adenomyosis-associated HMB were recruited. Of these, 37 women reported moderate/heavy bleeding (MHB) and the remaining 35 women reported excessive bleeding (EXB). The stiffness of adenomyotic lesions and neighbouring endometrial-myometrial interface (EMI) was measured by transvaginal elastosonography, and full-thickness uterine tissue columns were processed for Masson trichrome staining and immunohistochemistry analyses. The protein expression levels of HDAC3 in endometrial cells cultured on substrates of different stiffnesses, and the protein concentrations of nuclear factor-κB (NF-κB) p65 subunit with HDAC3 suppression were evaluated. Mouse experiments were performed to assess the effect of adenomyosis on Hdac3 expression, endometrial repair and bleeding, and to evaluate the effect of HDAC3 inhibition on endometrial repair.

RESULTS

Compared with controls, the endometrial staining of HDAC3 was significantly lower in women with adenomyosis-associated HMB, concomitant with a greater extent of fibrosis. The stiffness of lesions and neighbouring EMI was significantly higher in the EXB group compared with the MHB group, as was the extent of fibrosis in lesions, their neighboring EMI and endometrium. Expression of HDAC3 was reduced significantly when endometrial epithelial cells were cultured in stiff substrates. Suppression of HDAC3 abrogated the activation and signalling of NF-κB. Mice with induced adenomyosis exhibited reduced Hdac3 staining and elevated fibrosis in endometrium, concomitant with disrupted endometrial repair and more bleeding. Hdac3 inhibition resulted in botched inflammation and increased bleeding.

CONCLUSIONS

Lesional fibrosis results in reduced endometrial HDAC3 expression and subsequent disruption in NF-κB signalling and inflammation, leading to adenomyosis-associated HMB.

Effectiveness of Zhenqi Buxue Oral Liquid Combined with Progesterone for Treatment of Oligomenorrhea and Hypomenorrhea with Qi-Blood and Kidney (Shen) Essence Deficiency: A Randomized Controlled Trial

OBJECTIVE

To evaluate the effectiveness and safety of Zhenqi Buxue Oral Liquid (ZQ), progesterone capsules, and their combination in treating oligomenorrhea and hypomenorrhea with qi-blood and Kidney (Shen) essence deficiency.

METHODS

This was a prospective, randomized, multi-center controlled trial between June 2022 to December 2022. Ninety-six oligomenorrhea and hypomenorrhea patients with qi-blood and Shen essence deficiency were randomly assigned to receive ZQ (ZQ group, 29 cases), progesterone capsules (PG group, 32 cases), or the combined Chinese and Western medicine (COM group, 31 cases) at a ratio of 1:1:1. Patients in the ZQ or PG group took daily 10 mL twice a day of ZQ or 200 mg once a day of progesterone capsules for 10 consecutive days on day 15 of the menstrual cycle respectively, and patients in the COM group received the same ZQ combined with progesterone capsules. The treatment course lasted for 3 months and follow-up was performed at 1 and 3 months after the end of treatment. Primary endpoint was the menstrual Traditional Chinese Medicine Syndrome Scale (TCMSS) scores. Secondary endpoints included pictorial blood loss assessment chart (PBAC) scores, clinical efficacy rate, 36-item Short Form Health Survey (SF-36) scores, sex hormones and thickness of endometrium. Adverse events (AEs) were recorded.

RESULTS

TCMSS scores after 1- and 3-month treatment in all groups were significantly lower than those at baseline (P<0.05). Only TCMSS scores after 3-month treatment in the ZQ and COM groups continuously decreased compared with those after 1-month treatment in the same group (P<0.01). TCMSS scores after 3-month treatment in the ZQ and COM groups were significantly lower than those in the PG group (P<0.05, P<0.01). Compared with baseline, PBAC scores in the ZQ and COM groups after 3 months of treatment were also significantly higher (both P<0.01). The total effective rates of TCM syndrome of 3-month treatment were significantly improved in all groups compared with that after 1 month of treatment (P<0.05). The total effective rate of the COM group was the highest in the 3rd month of treatment and significantly higher than that of PG group alone (P<0.05). Compared with baseline, only the SF-36 scores of COM group were significantly improved after 3 months of treatment (P<0.05). No serious adverse reactions were observed after treatment.

CONCLUSIONS

The combination of ZQ and PG, or ZQ only had better effects on reducing TCMSS scores compared with PG, and COM showed the higher total effective rate compared with monotherapy. Besides, COM could effectively improve menstrual blood loss and quality of life. ZQ combined with PG may be an effective and safe option for oligomenorrhea and hypomenorrhea patients with qi-blood and Shen essence deficiency.

Endometriosis: Classification, pathophysiology, and treatment options

The human endometrium is a complex hormone-target tissue consisting of two layers: the lower basalis, and the upper functionalis. The latter of the two goes through a cycle of thickening and shedding without residual scarring or loss of function. This cycle, known as the menstrual cycle, occurs on a monthly basis in most of healthy reproductive-age women. It is, however, associated with a number of reproductive diseases, endometriosis being one of them. Endometriosis is defined as the presence of endometrium at ectopic sites within the peritoneum or, more rarely, other locations outside the abdominal area. It affects around 6-10% of reproductive-age women in the world and causes debilitating pain, heavy menstrual bleeding, pain during penetrative sex, and infertility. The etiology of the disease is not yet fully understood but the generally accepted theory is that the endometriotic lesions originate from viable eutopic endometrial cells that flow back into the peritoneum through the process of retrograde menstruation. Endometriosis is usually classified into four stages: minimal, mild, moderate, and severe, though it is important to note that the presentation of symptoms does not necessarily correspond to the disease progression. The immune system plays an important role in supporting the viability and growth of ectopic endometriotic tissue, all the while promoting chronic inflammation at the lesion sites, which causes prolonged pain. There is no definitive cure for endometriosis, but there are several options for symptom management, including laparoscopy, hormonal therapy, the use of NSAIDs, dietary changes, exercise, and, in cases when all conservative treatments fail, hysterectomy.

Changes in the immunophenotype of endometrium during implantation window receptivity formation in healthy fertile women

INTRODUCTION

Endometrial receptivity is largely determined by the immunophenotype of endometrium, especially uterine NK-cells (uNK). Immune component is directly involved in the formation of favourable microenvironment for the blastocyst implantation and placenta formation, but the way it changes during the maturation of endometrial tissue in healthy fertile women is still underexplored.

METHODS

The endometrium was collected from 47 healthy oocyte donors after controlled ovarian stimulation: 23 women on the day of oocytes retrieval (OR) and 24 women on the term of implantation window (IW). The OR group was analysed, published previously and used as a comparison group to show the dynamic of changes. Isolated endometrial lymphocytes and peripheral blood samples were stained with monoclonal antibodies and analysed according to the three-color flow cytometry protocol.

RESULTS

The proportion of NK-cells (CD3-CD56+) in endometrium grew significantly in the implantation window compared to the oocytes retrieval day. NK-cells acquired a more differentiated phenotype from the day of OR until IW: the expression of CD8 and CD158a significantly increased, while the expression of HLA-DR significantly decreased. Significant correlations between peripheral blood and endometrial NK-cells were found in CD8 expression during OR and IW, CD335(p46)neg and CD335(p46)++ subsets during IW term.

DISCUSSION

Immunophenotype of receptive endometrium forms due to the accumulation of uNK-cells, which actively proliferate, become mature, differentiative, and ready to meet the embryo. Endometrial immunophenotype is peculiar and specific but not autonomic and isolated. Differentiation (CD8 on NK-cells), and activity (p46 on NK-cells) of peripheral blood lymphocytes is reflected in endometrial lymphocytes profile, and therefore the research of peripheral blood immunophenotype is relevant.