Vasculogenesis and angiogenesis in the endometrium during menstrual cycle and implantation

Unveiling the Regulatory Role of LncRNA MYU in Hypoxia-Induced Angiogenesis via the miR-23a-3p Axis in Endothelial Cells

Background: Angiogenesis is essential for various physiological and pathological processes, such as embryonic development and cancer cell proliferation, migration, and invasion. Long noncoding RNAs (lncRNAs) play pivotal roles in normal homeostasis and disease processes by regulating gene expression through various mechanisms, including competing endogenous RNAs (ceRNAs) of target microRNAs (miRNAs). The lncRNA MYU is known to promote prostate cancer proliferation via the miR-184/c-Myc regulatory axis and to be upregulated in vascular endothelial cells under hypoxic conditions, which often occurs in solid tumors. In the present study, we investigated whether MYU might affect cancer growth by regulating angiogenesis in vascular endothelial cells under hypoxia. Methods: The expression of MYU-regulated miR-23a-3p and interleukin-8 (IL-8) in HUVEC cell lines was examined using qRT-PCR. The CCK-8 assay, EdU assay, wound-healing assay, and tube-formation assay were used to assess the effects of MYU on cell proliferation, migration, and tube formation of HUVEC cells in vitro. The dual-luciferase reporter assay was performed to examine the effects of miR-23a-3p on MYU and IL-8 expression. Results: We found that the overexpression of MYU and knockdown of miR-23a-3p in human umbilical vein endothelial cells (HUVECs) under hypoxia promoted cell proliferation, migration, and tube formation. Mechanistically, MYU was shown to bind competitively to miR-23a-3p, thereby preventing miR-23a-3p binding to the 3' untranslated region of IL-8 mRNA. In turn, increased production of pro-angiogenic IL-8 promoted HUVEC proliferation, migration, and tube formation under hypoxia. Conclusion: This study identified a new role for lncRNA MYU as a ceRNA for miR-23a-3p and uncovered a novel MYU-miR-23a-3p-IL-8 regulatory axis for angiogenesis. MYU and/or miR-23a-3p may thus represent new targets for the treatment of hypoxia-related diseases by promoting angiogenesis.

Endometrial decidualization status modulates endometrial microvascular complexity and trophoblast outgrowth in gelatin methacryloyl hydrogels

The endometrium undergoes rapid cycles of vascular growth, remodeling, and breakdown during the menstrual cycle and pregnancy. Decidualization is an endometrial differentiation process driven by steroidal sex hormones that is critical for blastocyst-uterine interfacing and blastocyst implantation. Certain pregnancy disorders may be linked to decidualization processes. However, much remains unknown regarding the role of decidualization and reciprocal trophoblast-endometrial interactions on endometrial angiogenesis and trophoblast invasion. Here, we report an engineered endometrial microvascular network embedded in gelatin hydrogels that displays morphological and functional patterns of decidualization. Vessel complexity and biomolecule secretion are sensitive to decidualization and affect trophoblast motility, but that signaling between endometrial and trophoblast cells was not bi-directional. Although endometrial microvascular network decidualization status influences trophoblast cells, trophoblast cells did not induce structural changes in the endometrial microvascular networks. These findings add to a growing literature that the endometrium has biological agency at the uterine-trophoblast interface during implantation. Finally, we form a stratified endometrial tri-culture model, combining engineered microvascular networks with epithelial cells. These endometrial microvascular networks provide a well-characterized platform to investigate dynamic changes in angiogenesis in response to pathological and physiological endometrial states.

HIF-1α regulates DcR3 to promote the development of endometriosis

OBJECTIVE

The aim of this study was to investigate the expression and clinical significance of HIF-1α and DcR3 in endometriosis by analysing clinical case data. Tissue samples were collected for tissue chip analysis and staining, and human endometrial stromal cells were isolated and cultured for cell experiments. Additionally, experiments were conducted on collected peritoneal fluid to explore the association and role of HIF-1α and DcR3 in endometriosis.

STUDY DESIGN

Patients who visited the Department of Obstetrics and Gynaecology at Central Hospital in Fengxian District, Shanghai, from January 2018 to December 2021 were recruited for this controlled study. Clinical data and tissue chip staining results were collected for multiple regression analysis on the clinical significance of HIF-1α and DcR3. Endometrial tissue, ovarian cysts, and pelvic fluid were collected, and human endometrial stromal cells were cultured. The impact of HIF-1α on DcR3 in different oxygen environments and its role in endometriosis were investigated through PCR, Western blotting, enzyme-linked immunosorbent assay, as well as adhesion and migration assays.

RESULTS

In patients with endometriosis, the expression of DcR3 and HIF-1α was found to be upregulated and correlated in ectopic endometrium. The expression of DcR3 served as an indicator of the severity of endometriosis. Hypoxia induced the expression of DcR3, which was regulated by HIF-1α and promoted migration and adhesion.

CONCLUSION

DcR3 can be used as a clinical indicator to assess the severity of endometriosis. The hypoxic environment in endometriosis enhances disease progression by regulating DcR3 through HIF-1α.

CREB1 Is Involved in miR-134-5p-Mediated Endometrial Stromal Cell Proliferation, Apoptosis, and Autophagy

The successful establishment of endometrial receptivity is a key factor in ensuring the fertility of ewes and their economic benefits. Hu sheep have attracted attention due to their high fecundity and year-round estrus. In this study, we found that in the luteal phase, the uterine gland density, uterine coefficient, and number of uterine caruncles of high-fertility Hu sheep were higher than those of low-fertility Hu sheep. Thousands of differentially expressed genes were identified in the endometrium of Hu sheep with different fertility potential using RNA sequencing (RNA-Seq). Several genes involved in endometrial receptivity were screened using bioinformatics analysis. The qRT-PCR analysis further revealed the differential expression of cAMP reactive element binding protein-1 (CREB1) in the Hu sheep endometrium during the estrous cycle. Functionally, our results suggested that CREB1 significantly affected the expression level of endometrial receptivity marker genes, promoted cell proliferation by facilitating the transition from the G1 phase to the S phase, and inhibited cell apoptosis and autophagy. Moreover, we observed a negative linear correlation between miR-134-5p and CREB1 in the endometrium. In addition, CREB1 overexpression prevented the negative effect of miR-134-5p on endometrial stromal cell (ESC) growth. Taken together, these data indicated that CREB1 was regulated by miR-134-5p and may promote the establishment of uterine receptivity by regulating the function of ESCs. Moreover, this study provides new theoretical references for identifying candidate genes associated with fertility.

Molecular Factors Involved in the Reproductive Morphophysiology of Female Domestic Cat (Felis catus)

The domestic cat (Felis catus) is considered an important model for the study of feline reproductive morphophysiology. However, although the morphological changes and clinical signs that occur during the estrous cycle and pregnancy are well known, little is known about the molecular mechanisms involved in the reproductive physiology of this animal species. Thus, this paper reviews the current knowledge about the modulation and expression profile of hormonal, immunological, redox, and growth mediators involved in the uterine, ovarian, and placental morphophysiology of domestic cats.

Cuyun Recipe ameliorates pregnancy loss by regulating macrophage polarization and hypercoagulable state during the peri-implantation period in an ovarian hyperstimulation mouse model

BACKGROUND

The Chinese herbal prescription Cuyun Recipe (CYR) has been widely used to treat clinical infertility and has shown good efficacy. Animal experiments have shown that CYR can promote implantation in mice, however, the exact mechanism underlying the implantation has not been elucidated.

PURPOSE

To investigate the effect and mechanism of CYR on regulating macrophage polarization and hypercoagulability during the peri-implantation period in mice with ovarian hyperstimulation.

METHODS

An ovarian hyperstimulation mouse model was developed, followed by treatment with CYR. Mice were sacrificed on day (D)4.5, D6, or D8 of gestation. The number of implantation sites, the pathological changes of the uterus and ovaries were assessed. The polarization of monocytes/macrophages in the spleen and endometrium, the expression and localization of cytokines were further detected. Furthermore, analyses of hypercoagulable state of the blood were also performed.

RESULTS

Treatment with CYR increased the average number of implantation sites, promoted angiogenesis in endometrial, and regulated monocytes/macrophages and the cytokine levels. Moreover, CYR downregulated the overexpression of D-dimer and fgl2 after ovarian hyperstimulation.

CONCLUSION

CYR facilitates embryo implantation by alleviating ovarian hyperstimulation, promoting endometrial decidualization and angiogenesis, regulating macrophage polarization, and reversing the hypercoagulable state of the blood.

Field-of-view optimized and constrained undistorted single-shot study of intravoxel incoherent motion and diffusion-weighted imaging of the uterus during the menstrual cycle: a prospective study

PURPOSE

This study aimed to compare the variability of the uterus during the menses phase (MP), follicular phase (FP), and luteal phase (LP) of the menstrual cycle using intravoxel incoherent motion diffusion-weighted imaging (IVIM-DWI).

METHODS

This prospective study was conducted at the Guangdong Provincial Hospital of Traditional Chinese Medicine between January 2022 and January 2023. Women of childbearing age (18-45 years) with appropriate progesterone levels were included in this study. Conventional magnetic resonance imaging and IVIM-DWI scans were performed during the MP, FP, and LP. The differences in IVIM-DWI-derived parameters between these phases were then compared, and the overlap was quantitatively described.

RESULTS

The apparent diffusion coefficient (ADC) and pure molecular diffusion coefficient (D) values from the endometrium, uterine junctional zone (UJZ), and myometrium indicated statistical differences between the MP and FP and the MP and LP (ADC: endometrium, both P < 0.001; UJZ, P = 0.008 and P < 0.001, respectively; myometrium, P = 0.033 and P = 0.006, respectively; D: endometrium, both P < 0.001; UJZ, P = 0.008 and P = 0.006, respectively; myometrium, P = 0.041 and P = 0.045, respectively). The perfusion-related diffusion coefficient (D*) values from the myometrium indicated statistical differences between the FP and MP and the FP and LP (D*: myometrium, P = 0.049 and P = 0.009, respectively). The overlapping endometrium ratios between the MP and FP or LP were lower than 50% in the ADC and D values (ADC: overlapping of MP and FP: 33.33%, overlapping of MP and LP: 23.33%; D: overlapping of MP and FP: 40.00%, overlapping of MP and LP: 43.33%).

CONCLUSION

The ADC and IVIM-derived parameters indicated differences in the uterus in diverse phases of the menstrual cycle, especially in the endometrium in relation to ADC and D values.

Unveiling the angiogenic effects of cannabinoids: Enhancers or inhibitors?

Cannabinoids are compounds found in the cannabis sativa plant. Cannabinoids, such as delta-9-tetrahydrocannabinol (THC) and cannabidiol (CBD), have potential therapeutic benefits in various medical conditions. Some can activate the cannabinoid receptors type-1 and -2 (CB1 and CB2), that are part of the endocannabinoid system (ECS), alongside the endocannabinoids and their metabolic enzymes. The ECS regulates physiological and cognitive processes and is a potential therapeutic target for a wide range of health conditions like chronic pain, anxiety, and neurodegenerative diseases. Synthetic cannabinoids, are associated with serious health risks, including addiction, psychosis, and death. Nonetheless, some of these molecules are also being explored for pharmacological applications. Angiogenesis is the process of forming new blood vessels from existing ones, crucial for growth, repair, and tissue maintenance. Dysregulation of this process is associated with several diseases, including cancer, diabetic retinopathy and reproductive pathologies, such as preeclampsia. Recent data suggests that cannabinoids may affect angiogenesis. Here, we reviewed their impact on pro-angiogenic factors, extracellular matrix enzymes and inhibitors, immune-inflammatory responses, angiogenic pathways and functional assays, focusing on the main compounds for each cannabinoid class: THC and CBD for phytocannabinoids, anandamide (AEA) and 2-arachidonoylglycerol (2-AG) for endocannabinoids and WIN-55, JWH-133, XLR-11, LYR-7 and LYR-8, for the synthetic cannabinoids. Despite conflicting reports about the actions of phytocannabinoids and endocannabinoids on angiogenesis, the ability to modulate the angiogenic process is undoubtedly confirmed. This may open a new therapeutical route for angiogenesis-related pathologies. In addition, synthetic cannabinoids present anti-angiogenic actions in several cell models, hinting their potential as anti-angiogenic drugs.

Angiogenic Microvascular Wall Shear Stress Patterns Revealed Through Three-dimensional Red Blood Cell Resolved Modeling

The wall shear stress (WSS) exerted by blood flowing through microvascular capillaries is an established driver of new blood vessel growth, or angiogenesis. Such adaptations are central to many physiological processes in both health and disease, yet three-dimensional (3D) WSS characteristics in real angiogenic microvascular networks are largely unknown. This marks a major knowledge gap because angiogenesis, naturally, is a 3D process. To advance current understanding, we model 3D red blood cells (RBCs) flowing through rat angiogenic microvascular networks using state-of-the-art simulation. The high-resolution fluid dynamics reveal 3D WSS patterns occurring at sub-endothelial cell (EC) scales that derive from distinct angiogenic morphologies, including microvascular loops and vessel tortuosity. We identify the existence of WSS hot and cold spots caused by angiogenic surface shapes and RBCs, and notably enhancement of low WSS regions by RBCs. Spatiotemporal characteristics further reveal how fluctuations follow timescales of RBC "footprints." Altogether, this work provides a new conceptual framework for understanding how shear stress might regulate EC dynamics in vivo.

Decreased Gene Expression of Antiangiogenic Factors in Endometrial Cancer: qPCR Analysis and Machine Learning Modelling

Endometrial cancer (EC) is an increasing health concern, with its growth driven by an angiogenic switch that occurs early in cancer development. Our study used publicly available datasets to examine the expression of angiogenesis-related genes and proteins in EC tissues, and compared them with adjacent control tissues. We identified nine genes with significant differential expression and selected six additional antiangiogenic genes from prior research for validation on EC tissue in a cohort of 36 EC patients. Using machine learning, we built a prognostic model for EC, combining our data with The Cancer Genome Atlas (TCGA). Our results revealed a significant up-regulation of IL8 and LEP and down-regulation of eleven other genes in EC tissues. These genes showed differential expression in the early stages and lower grades of EC, and in patients without deep myometrial or lymphovascular invasion. Gene co-expressions were stronger in EC tissues, particularly those with lymphovascular invasion. We also found more extensive angiogenesis-related gene involvement in postmenopausal women. In conclusion, our findings suggest that angiogenesis in EC is predominantly driven by decreased antiangiogenic factor expression, particularly in EC with less favourable prognostic features. Our machine learning model effectively stratified EC based on gene expression, distinguishing between low and high-grade cases.

The role of inflammatory biomarkers in the development and progression of pre-eclampsia: a systematic review and meta-analysis

Background

Pre-eclampsia (PE) is a pregnancy complication associated with maternal and fetal morbidity and mortality. Among the potential pathogenesis discussed, inflammation is considered an essential initiator of PE. Previous studies have compared the levels of various inflammatory biomarkers that indicate the existence of PE; however, the relative levels of pro-inflammatory and anti-inflammatory biomarkers and their dynamic changes during PE progression remain unclear. This knowledge is essential to explain the occurrence and progression of the disease.

Objective

We aimed to identify the relationship between inflammatory status and PE using inflammatory biomarkers as indicators. We also discussed the underlying mechanism by which inflammatory imbalance contributes to PE by comparing the relative levels of pro-inflammatory and anti-inflammatory biomarkers. Furthermore, we identified additional risk factors for PE.

Methods

We reviewed PubMed, Embase, and the Cochrane Library for articles published until 15th September 2022. Original articles that investigated inflammatory biomarkers in PE and normal pregnancy were included. We selected healthy pregnant women as controls. The inflammatory biomarkers in the case and control groups were expressed as standardized mean differences and 95% confidence intervals using a random-effects model. Study quality was assessed using the Newcastle-Ottawa Scale. Publication bias was assessed using Egger's test.

Results

Thirteen articles that investigated 2,549 participants were included in this meta-analysis. Patients with PE had significantly higher levels of C-reactive protein (CRP), interleukin (IL)-4, IL-6, IL-8, IL-10, and tumor necrosis factor (TNF) than the controls. CRP and pro-inflammatory cytokine levels were higher than those of anti-inflammatory cytokines. Patients with gestational age > 34 weeks had significantly higher IL-6 and TNF levels. Patients with higher systolic blood pressure had significantly higher IL-8, IL-10, and CRP levels.

Conclusion

Inflammatory imbalance is an independent risk factor for PE development. Impairment of the anti-inflammatory system is a crucial initiating factor for PE development. Failed autoregulation, manifested as prolonged exposure to pro-inflammatory cytokines, leads to PE progression. Higher levels of inflammatory biomarkers suggest more severe symptoms, and pregnant women after 34 weeks of gestation are more susceptible to PE.

Vascularisation in Deep Endometriosis: A Systematic Review with Narrative Outcomes

Deep endometriosis (DE) is the most severe subtype of endometriosis, with the hallmark of lesions infiltrating adjacent tissue. Abnormal vascularisation has been implicated in contributing to endometriosis lesion development in general, and how vascularisation influences the pathogenesis of DE, in particular, is of interest. This systematic review followed the PRISMA guidelines to elucidate and examine the evidence for DE-specific vascularisation. A literature search was performed using MEDLINE, Embase, PubMed, Scopus, Cochrane CENTRAL Library and Europe PubMed Central databases. The databases were searched from inception to the 13 March 2023. A total of 15 studies with 1125 patients were included in the review. The DE lesions were highly vascularised, with a higher microvessel density (MVD) than other types of endometriotic lesions, eutopic endometrium from women with endometriosis and control tissue. Vascular endothelial growth factor, its major subtype (VEGF-A) and associated receptor (VEGFR-2) were significantly increased in the DE lesions compared to superficial endometriosis, eutopic endometrium and control tissue. Progestin therapy was associated with a significant decrease in the MVD of the DE lesions, explaining their therapeutic effect. This review comprehensively summarises the available literature, reporting abnormal vascularisation to be intimately related to the pathogenesis of DE and presents potentially preferential therapeutic targets for the medical management of DE.

CmPn/CmP Signaling Networks in the Maintenance of the Blood Vessel Barrier

Cerebral cavernous malformations (CCMs) arise when capillaries within the brain enlarge abnormally, causing the blood-brain barrier (BBB) to break down. The BBB serves as a sophisticated interface that controls molecular interactions between the bloodstream and the central nervous system. The neurovascular unit (NVU) is a complex structure made up of neurons, astrocytes, endothelial cells (ECs), pericytes, microglia, and basement membranes, which work together to maintain blood-brain barrier (BBB) permeability. Within the NVU, tight junctions (TJs) and adherens junctions (AJs) between endothelial cells play a critical role in regulating the permeability of the BBB. Disruptions to these junctions can compromise the BBB, potentially leading to a hemorrhagic stroke. Understanding the molecular signaling cascades that regulate BBB permeability through EC junctions is, therefore, essential. New research has demonstrated that steroids, including estrogens (ESTs), glucocorticoids (GCs), and metabolites/derivatives of progesterone (PRGs), have multifaceted effects on blood-brain barrier (BBB) permeability by regulating the expression of tight junctions (TJs) and adherens junctions (AJs). They also have anti-inflammatory effects on blood vessels. PRGs, in particular, have been found to play a significant role in maintaining BBB integrity. PRGs act through a combination of its classic and non-classic PRG receptors (nPR/mPR), which are part of a signaling network known as the CCM signaling complex (CSC). This network couples both nPR and mPR in the CmPn/CmP pathway in endothelial cells (ECs).

Immunomodulation of the Vaginal Ecosystem by Ligilactobacillus salivarius CECT 30632 Improves Pregnancy Rates among Women with Infertility of Unknown Origin or Habitual Abortions

In this study, the probiotic potential of Ligilactobacillus salivarius CECT 30632 was assessed, including properties specifically related with gynecological targets. This strain displayed co-aggregative and antimicrobial activity against a wide spectrum of vaginal pathogens while being respectful with the growth of vaginal lactobacilli. The strain produced a high concentration of lactic acid and displayed α-amylase activity when assayed in vitro. It showed a noticeable survival rate after exposition to conditions similar to those present in the human digestive tract and was adhesive to both vaginal and intestinal cells. Subsequently, their capacity to increase pregnancy rates among women with habitual abortion or infertility of unknown origin was studied. Administration of L. salivarius CECT 30632 (~9 log₁₀ CFU) daily for a maximum of six months to these women was safe and led to a successful pregnancy rate of 67.5% (80% and 55% for women with repetitive abortion and infertile women, respectively). Significant differences in Nugent score, vaginal pH, and vaginal concentrations of lactobacilli, TGF-β, and VEFG were observed when the samples collected before the intervention were compared with those collected after the treatment among those women who got pregnant. Therefore, this strain can modulate the vaginal ecosystem and lead to better fertility outcomes.

Ultrasound Molecular Imaging of Neovascularization for Evaluation of Endometrial Receptivity Using Magnetic iRGD-Modified Lipid-Polymer Hybrid Microbubbles

BACKGROUND

Angiogenesis plays an important role in endometrial receptivity, determining the response of the endometrium to the blastocyst at the early stage of embryo implantation. During the application of assisted reproduction technologies, it is very important to evaluate the status of uterine angiogenesis before deciding on embryo implantation. Targeted microbubbles (MBs)-based ultrasound molecular imaging (UMI) can noninvasively detect the expression status of biomarkers at the molecular level, thereby being a potential diagnosis strategy for various diseases and their therapeutic evaluation.

METHODS

The iRGD-lipopeptide (DSPE-PEG2000-iRGD) conjugate was prepared with iRGD peptides and DSPE-PEG2000-maleimide through the Michael-type addition reaction. Then, the magnetic iRGD-modified lipid-polymer hybrid MBs (Mag-iLPMs) were prepared with the double-emulsification-solvent-evaporation method. Magnetic targeting of Mag-iLPMs was confirmed under the microscope, followed by a rectangular magnet. Next, the in vitro targeted binding of MBs to murine brain-derived endothelial cells.3 (bEnd.3) and human umbilical vein endothelial cells (HUVEC) were evaluated. The ratio of MBs binding to bEnd.3 and HUVEC at the same field was also compared. For in vivo studies, bolus injections of targeted or control MBs were randomly administrated to non-pregnant or pregnant rats on day 5. Then, the uteri were imaged using a VisualSonics Vevo 2100 ultrasound system (Fujifilm VisualSonics Inc., Ontario, Canada) equipped with a high-frequency transducer. Ultrasonic imaging signals were acquired from Mag-iLPMs, and compared with Mag-LPMs, iLPMs, and LPMs.

RESULTS

The Mag-iLPMs showed excellent performance in ultrasound contrast imaging and binding affinity to target cells. Using the magnetic field, 10.5- and 12.47-fold higher binding efficiency to bEnd.3 and HUVEC were achieved compared to non-magnetic iLPMs, respectively. Significantly enhanced UMI signals were also observed in the uteri of rats intravenously injected pregnant rats (6.58-fold higher than rats injected with iLPMs).

CONCLUSION

We provided a powerful ultrasonic molecular functional imaging tool for uterine angiogenesis evaluation before embryonic implantation.

Platelet-rich plasma treatment in patients with refractory thin endometrium and recurrent implantation failure: A comprehensive review

Refractory thin endometrium and recurrent implantation failure are among the most challenging infertility-related factors hindering successful pregnancy. Several adjuvant therapies have been investigated to increase endometrial thickness and the pregnancy rate, but the treatment effect is still minimal, and for many patients, these treatment methods can be quite costly and difficult to approach. Platelet-rich plasma (PRP) is an autologous concentration of platelets in plasma and has recently been elucidated as a better treatment option for these patients. PRP is rich in cytokines and growth factors, which are suggested to exert a regenerative effect at the level of the injured tissue. Another advantage of PRP is that it is easily obtained from the patient’s own blood. We aimed to review the recent findings of PRP therapy used for patients with refractory thin endometrium and recurrent implantation failure.

Effects of smoking on the tissue regeneration-associated functions of human endometrial stem cells via a novel target gene SERPINB2

BACKGROUND

Smokers directly inhale mainstream cigarette smoke, which contains numerous known and potential toxic substances, and thus, smoking is expected to have broad harmful effects that cause tissue injury and dysfunction. Interestingly, many studies have suggested that the recent decline in female fertility and increased rate of spontaneous abortion could be associated with increased smoking rates. Indeed, women that smoked for 10 years or more were reported to have a ~ 20% higher infertility rate than women that had never smoked. However, the reasons for the underlying harmful aspects of smoking on female fertility remain a matter of debate. Importantly, a previous study revealed that resident endometrial stem cell deficiency significantly limits the cyclic regeneration potential of endometrium, which, in turn, decreases successful pregnancy outcomes. In this context, we postulated that exposure to mainstream cigarette smoke extracts might decrease female fertility by inhibiting the functions of resident endometrial stem cells.

METHODS

We investigated whether cigarette mainstream smoke exposure directly inhibits various tissue regeneration-associated functions of endometrial stem cells, such as self-renewal, migration, pluripotency, and differentiation capacity in vitro. Next, we determined whether SERPINB2 mediates cigarette smoke-induced suppressive effects on various tissue regeneration-associated functions by depleting SERPINB2 expression with specific shRNA targeting SERPINB2. Mice were injected intraperitoneally with low (0.5 mg/kg) or high (1 mg/kg) doses of cigarette smoke extract (10 times for two weeks), and endometrial stem cells were then isolated from mice uterine tissues.

RESULTS

We found that exposure to cigarette smoke extracts remarkably suppressed various tissue regeneration-associated functions of endometrial stem cells, such as self-renewal, migration, multilineage differentiation ability, and pluripotency in vitro and in vivo by activating the SERPINB2 gene. Indeed, cigarette smoke-induced inhibitory effects on various endometrial stem cell functions were significantly abolished by SERPINB2 knockdown.

CONCLUSIONS

These findings provide valuable information on the harmful effects of cigarette smoking on resident endometrial stem cells and hopefully will facilitate the developments of promising therapeutic strategies for subfertile or infertile women that smoke cigarettes.

The Value of Intratumoral and Extratumoral Microvessel Density for the Tumor-dominated Area in the Endometrial Carcinoma

OBJECTIVE

Microvessel density (MVD) measuring angiogenesis can influence clinicopathologic variables in endometrial carcinoma (EC). MVD is usually assessed in the densest vascular area the tumor, but the distinction between intratumoral and extratumoral MVD is not reported, and tumor-dominated area is not examined for MVD in the EC in the literature.

MATERIALS AND METHODS

A total of 151 cases with EC, which had hysterectomy from 2005 to 2020, were included. All histopathologic parameters were re-evaluated blindly. MVD was counted in the intratumoral (densest tumoral and vascular area) and extratumoral (periphery of the tumor, tumor invasion tip, densest tumoral, and vascular area) areas using immunohistochemical CD31 expression.

RESULTS

Large tumor size, deep myometrial invasion, high grade, nonendometrioid tumor type, cervix invasion, lymph node metastasis, human epidermal growth factor receptor 2 positivity, stage III to IV, substantial lymphovascular invasion, and overall survival had significant relations with intratumoral and extratumoral MVD ( P <0.05). Age and lymphoplasmacytic inflammation showed marginal significance for extratumoral MVD. Extratumoral and intratumoral MVD had high (near-perfect) agreement (κ=0.870, P =0.001). Cervix invasion, stage III to IV, high grade, intratumoral, and extratumoral MVD were correlated with lower overall survival in the multivariate analyses.

CONCLUSION

High MVD had an impact on the behavior and prognosis of EC and may be a potential indicator for antiangiogenic treatments for aggressive tumors. Although intratumoral and extratumoral MVD in the tumor-dominated area have mostly similar effects in our study, this situation can be cleared more by further investigations.

Autophagy: A Key Player in Pancreatic Cancer Progression and a Potential Drug Target

Pancreatic cancer is known to have the lowest survival outcomes among all major cancers, and unfortunately, this has only been marginally improved over last four decades. The innate characteristics of pancreatic cancer include an aggressive and fast-growing nature from powerful driver mutations, a highly defensive tumor microenvironment and the upregulation of advantageous survival pathways such as autophagy. Autophagy involves targeted degradation of proteins and organelles to provide a secondary source of cellular supplies to maintain cell growth. Elevated autophagic activity in pancreatic cancer is recognized as a major survival pathway as it provides a plethora of support for tumors by supplying vital resources, maintaining tumour survival under the stressful microenvironment and promoting other pathways involved in tumour progression and metastasis. The combination of these features is unique to pancreatic cancer and present significant resistance to chemotherapeutic strategies, thus, indicating a need for further investigation into therapies targeting this crucial pathway. This review will outline the autophagy pathway and its regulation, in addition to the genetic landscape and tumor microenvironment that contribute to pancreatic cancer severity. Moreover, this review will also discuss the mechanisms of novel therapeutic strategies that inhibit autophagy and how they could be used to suppress tumor progression.

Effects of hysterosalpingo-contrast sonography examination on endometrial receptivity among women with unexplained infertility

PURPOSE

Hysterosalpingo-contrast sonography (HyCoSy) is the preferred method for evaluating fallopian tubal patency, and it is associated with improved rates of natural pregnancy among infertile patients. However, the mechanism underlying the improvement in pregnancy rates following HyCoSy remains unclear. This study aimed to investigate the effect of HyCoSy examination on endometrial receptivity as well as pregnancy rates among infertile women.

METHODS

This prospective study included 120 women with unexplained infertility who visited our department between June 2018 and February 2021. These patients were classified into the study group (n = 60) and the control group (n = 60) depending on their willingness to undergo three-dimensional HyCoSy in the present cycle (study group) or 6 months later (control group). Endometrial characteristics, including endometrial thickness and pattern as well as the endometrial blood flow distribution pattern, were measured twice by transvaginal Doppler ultrasonography in the preovulatory phase before and after HyCoSy examination. Participants were followed for 6 months to observe the outcome of spontaneous conception.

RESULTS

Compared with the control group, the study group had a significantly higher cumulative pregnancy rate at 6 months after HyCoSy (21.6% [13/60] vs 5.0% [3/60], P = 0.007). More patients in the study group showed improved endometrial blood flow distribution (P = 0.021, χ² = 7.699), but no differences in endometrial thickness and pattern were observed between the groups (P > 0.05).

CONCLUSION

HyCoSy examination may improve endometrial perfusion and has a therapeutic effect on improving spontaneous pregnancy among women with unexplained infertility.

Therapeutic Effects and Repair Mechanism of HGF Gene-Transfected Mesenchymal Stem Cells on Injured Endometrium

There are many studies on the advantages of using mesenchymal stem cells (MSCs) that secrete various paracrine factors for repairing endometrial injury. However, the stability and effectiveness of MSCs require improvement to become a viable therapy. Hepatocyte growth factor (HGF), one of the cytokines secreted by MSCs, promotes vascular repair and mesenchymal to epithelial transformation (MET). Therefore, HGF likely promotes the repair process of the endometrium. We prepared MSCs transfected with the HGF gene to explore its repair effects and mechanism using a damaged endometrium mouse model. HGF gene-transfected MSCs were prepared by electroporation. The transfected MSCs retained their cellular characteristics and significantly increased the expression of HGF ( $P<0.01$ ). HGF gene-transfected MSCs helped damaged endometrium to recover its morphological characteristics, improved proliferation and decreased apoptosis of endometrial cells, increased the expression of endometrial vascular growth-related factors, and activated phosphorylated c-Met and AKT in the mouse endometrial damage model ( $P<0.05$ ). Compared with normal MSCs, HGF gene-transfected MSCs produced a more significant effect on damaged endometrial epithelium repair by activating the HGF/c-Met and downstream signaling pathways. Our results indicate that HGF gene-transfected MSCs provide an effective and promising tool for injured endometrium therapy.

Maternal and Fetal-Placental Effects of Etanercept Treatment During Rats’ Pregnancy

Etanercept is a tumor necrosis factor alpha (TNF-α) inhibitor chronically used to treat autoimmune diseases. However, the use of etanercept during pregnancy still needs to be further investigated. The aim of this study is to evaluate the etanercept treatment during pregnancy, analyzing maternal reproductive performance, fetal outcomes, and placental repercussions. Wistar rats (200–250 g) were mated and randomly distributed into two experimental groups: control and etanercept (n = 10 animals/group). Treatments with etanercept (0.8 mg/kg, s.c.), or saline (control group) were carried out on days 0, 6, 12, and 18 of gestation. On the morning of the 21st day of pregnancy, rats were euthanized in a CO₂ chamber and submitted to laparotomy to remove the fetuses, placentas, ovaries, and maternal organs. There were no differences between groups in the following parameters: water and food consumption; placental efficiency; reproductive parameters, including number of corpora lutea and implants, reabsorption, and pre- and post-implantation losses. However, etanercept treatment increased liver weight, reduced fetal and placental weight, decreased the placental junction zone, reduced the percentage of normal fetuses, and increased visceral or skeletal fetal abnormalities. Therefore, etanercept resulted in damages more related to fetus and placenta. However, more studies with different doses are required to better predict possible injuries elicited using etanercept during pregnancy.

Human amniotic mesenchymal stem cells combined with PPCNg facilitate injured endometrial regeneration

BACKGROUND

Caused by the injury to the endometrial basal layer, intrauterine adhesions (IUA) are characterized by uterine cavity obliteration, leading to impaired fertility. Human amniotic mesenchymal stem cells (hAMSCs) have the potential to promote endometrial regeneration mainly through paracrine ability. PPCNg is a thermoresponsive biomaterial consisted of Poly (polyethylene glycol citrate-co-N-isopropylacrylamide) (PPCN) mixed with gelatin, which has been reported as a scaffold for stem cell transplantation. This study aims to investigate the therapeutic effect of hAMSCs combined with PPCNg transplantation in promoting the regeneration of injured endometrium.

METHODS

hAMSCs were cultured in different concentrates of PPCNg in vitro, and their proliferation, apoptosis and cell cycle were examined by CCK-8 assay and flow cytometry. Immunofluorescence was used to determine the MSCs specific surface markers. The expression of pluripotent genes was analyzed by qRT-PCR. The multiple-lineage differentiation potential was further evaluated by detecting the differentiation-related genes using qRT-PCR and specific staining. The Sprague-Dawley (SD) rat IUA model was established with 95% ethanol. hAMSCs combined with PPCNg were transplanted through intrauterine injection. The retention of DiR-labeled hAMSCs was observed by vivo fluorescence imaging. The endometrium morphology was assessed using hematoxylin and eosin (H&E) and Masson staining. Immunohistochemistry staining was performed to detect biomarkers related to endometrial proliferation, re-epithelialization, angiogenesis and endometrial receptivity. The function of regenerated endometrium was evaluated by pregnancy tests.

RESULTS

hAMSCs maintained normal cell proliferation, apoptosis and cell cycle in PPCNg. Immunofluorescence and qRT-PCR showed that hAMSCs cultured in PPCNg and hAMSCs cultured alone expressed the same surface markers and pluripotent genes. hAMSCs exhibited normal multilineage differentiation potential in PPCNg. Vivo fluorescence imaging results revealed that the fluorescence intensity of hAMSCs combined with PPCNg intrauterine transplantation was stronger than that of direct hAMSCs intrauterine transplantation. Histological assays showed the increase in the thickness of endometrial and the number of endometrial glands, and the remarkably decrease in the fibrosis area in the PPCNg/hAMSCs group. The expressions of Ki-67, CK7, CK19, VEGF, ER and PR were significantly increased in the PPCNg/hAMSCs group. Moreover, the number of implanted embryos and pregnancy rate were significantly higher in the PPCNg/hAMSCs group than in the hAMSCs group.

CONCLUSIONS

PPCNg is suitable for growth, phenotype maintenance and multilineage differentiation of hAMSCs. hAMSCs combined with PPCNg intrauterine transplantation can facilitate the regeneration of injured endometrium by improving utilization rates of hAMSCs, and eventually restore reproductive capacity.

OUP accepted manuscript

STUDY QUESTION

Can the accuracy of timing of luteal phase endometrial biopsies based on urinary ovulation testing be improved by measuring the expression of a small number of genes and a continuous, non-categorical modelling approach?

SUMMARY ANSWER

Measuring the expression levels of six genes (IL2RB, IGFBP1, CXCL14, DPP4, GPX3 and SLC15A2) is sufficient to obtain substantially more accurate timing estimates and to assess the reliability of timing estimates for each sample.

WHAT IS KNOWN ALREADY

Commercially available endometrial timing approaches based on gene expression require large gene sets and use a categorical approach that classifies samples as pre-receptive, receptive or post-receptive.

STUDY DESIGN, SIZE, DURATION

Gene expression was measured by RTq-PCR in different sample sets, comprising a total of 664 endometrial biopsies obtained 4–12 days after a self-reported positive home ovulation test. A further 36 endometrial samples were profiled by RTq-PCR as well as RNA-sequencing.

PARTICIPANTS/MATERIALS, SETTING, METHODS

A computational procedure, named ‘EndoTime’, was established that models the temporal profile of each gene and estimates the timing of each sample. Iterating these steps, temporal profiles are gradually refined as sample timings are being updated, and confidence in timing estimates is increased. After convergence, the method reports updated timing estimates for each sample while preserving the overall distribution of time points.

MAIN RESULTS AND THE ROLE OF CHANCE

The Wilcoxon rank-sum test was used to confirm that ordering samples by EndoTime estimates yields sharper temporal expression profiles for held-out genes (not used when determining sample timings) than ordering the same expression values by patient-reported times (GPX3: P < 0.005; CXCL14: P < 2.7e−6; DPP4: P < 3.7e−13). Pearson correlation between EndoTime estimates for the same sample set but based on RTq-PCR or RNA-sequencing data showed a high degree of congruency between the two (P = 8.6e−10, R² = 0.687). Estimated timings did not differ significantly between control subjects and patients with recurrent pregnancy loss or recurrent implantation failure (P > 0.05).

LARGE SCALE DATA

The RTq-PCR data files are available via the GitHub repository for the EndoTime software at https://github.com/AE-Mitchell/EndoTime, as is the code used for pre-processing of RTq-PCR data. The RNA-sequencing data are available on GEO (accession GSE180485).

LIMITATIONS, REASONS FOR CAUTION

Timing estimates are informed by glandular gene expression and will only represent the temporal state of other endometrial cell types if in synchrony with the epithelium. Methods that estimate the day of ovulation are still required as these data are essential inputs in our method. Our approach, in its current iteration, performs batch correction such that larger sample batches impart greater accuracy to timing estimations. In theory, our method requires endometrial samples obtained at different days in the luteal phase. In practice, however, this is not a concern as timings based on urinary ovulation testing are associated with a sufficient level of noise to ensure that a variety of time points will be sampled.

WIDER IMPLICATIONS OF THE FINDINGS

Our method is the first to assay the temporal state of luteal-phase endometrial samples on a continuous domain. It is freely available with fully shared data and open-source software. EndoTime enables accurate temporal profiling of any gene in luteal endometrial samples for a wide range of research applications and, potentially, clinical use.

STUDY FUNDING/COMPETING INTEREST(S)

This study was supported by a Wellcome Trust Investigator Award (Grant/Award Number: 212233/Z/18/Z) and the Tommy's National Miscarriage Research Centre. None of the authors have any competing interests. J.L. was funded by the Biotechnology and Biological Sciences Research Council (UK) through the Midlands Integrative Biology Training Partnership (MIBTP, BB/M01116X/1).

Killer Timing: The Temporal Uterine Natural Killer Cell Differentiation Pathway and Implications for Female Reproductive Health

Natural killer (NK) cells are the predominant maternal uterine immune cell component, and they densely populate uterine mucosa to promote key changes in the post-ovulatory endometrium and in early pregnancy. It is broadly accepted that (a) immature, inactive endometrial NK (eNK) cells in the pre-ovulatory endometrium become activated and transition into decidual NK (dNK) cells in the secretory stage, peri-implantation endometrium, and continue to mature into early pregnancy; and (b) that secretory-stage and early pregnancy dNK cells promote uterine vascular growth and mediate trophoblast invasion, but do not exert their killing function. However, this may be an overly simplistic view. Evidence of specific dNK functional killer roles, as well as opposing effects of dNK cells on the uterine vasculature before and after conception, indicates the presence of a transitory secretory-stage dNK cell (s-dNK) phenotype with a unique angiodevelopmental profile during the peri-implantation period, that is that is functionally distinct from the angiomodulatory dNK cells that promote vessel destabilisation and vascular cell apoptosis to facilitate uterine vascular changes in early pregnancy. It is possible that abnormal activation and differentiation into the proposed transitory s-dNK phenotype may have implications in uterine pathologies ranging from infertility to cancer, as well as downstream effects on dNK cell differentiation in early pregnancy. Further, dysregulated transition into the angiomodulatory dNK phenotype in early pregnancy will likely have potential repercussions for adverse pregnancy outcomes, since impaired dNK function is associated with several obstetric complications. A comprehensive understanding of the uterine NK cell temporal differentiation pathway may therefore have important translational potential due to likely NK phenotypic functional implications in a range of reproductive, obstetric, and gynaecological pathologies.

Differential expression of Hsa-miR-517a/b in placental tissue may contribute to the pathogenesis of preeclampsia

Objective:

Preeclampsia (PE) is a pregnancy hypertensive disorder that affects both maternal and fetal health. Many studies have investigated possible mechanisms in the pathogenesis of PE although the role of the placenta is undeniable. Evaluation of placental-specific microRNAs may provide additional data about the pathogenic mechanism of PE. This study compared the expression levels of Hsa-miR-517a/b in placental tissues obtained from PE patients and healthy controls.

Material and Methods:

One hundred tissues were obtained from fetal and maternal sides of the placenta of PE patients and healthy controls. Expression analysis was performed using quantitative real-time polymerase chain reaction.

Results:

Hsa-miR-517a/b level was significantly decreased in PE compared to controls (expression ratio: 0.40; p=0.007). Down-regulation of Hsa-miR-517a/b was also detected in fetal-side placental samples when compared to maternal-side in PE (expression ratio: 0.33; p=0.04). Furthermore, decreased expression of Hsa-miR-517a/b was detected in fetal-side tissue from PE cases compared to fetal-side samples from healthy pregnancies (expression ratio: 0.36; p=0.03). In maternal-side placental samples the expression level did not differ between PE and healthy pregnancies (p=0.1).

Conclusion:

These results demonstrate a differential expression of Hsa-miR-517a/b within placentas in pregnancies affected by PE and between placentas from PE and healthy pregnancies. Further studies are required to investigate a possible role for Hsa-miR-517a/b in the pathogenesis of PE.

The impact of fine particulate matter (PM) on various beneficial functions of human endometrial stem cells through its key regulator SERPINB2

Fine particulate matter (PM) has a small diameter but a large surface area; thus, it may have broad toxic effects that subsequently damage many tissues of the human body. Interestingly, many studies have suggested that the recent decline in female fertility could be associated with increased PM exposure. However, the precise mechanisms underlying the negative effects of PM exposure on female fertility are still a matter of debate. A previous study demonstrated that resident stem cell deficiency limits the cyclic regenerative capacity of the endometrium and subsequently increases the pregnancy failure rate. Therefore, we hypothesized that PM exposure induces endometrial tissue damage and subsequently reduces the pregnancy rate by inhibiting various beneficial functions of local endometrial stem cells. Consistent with our hypothesis, we showed for the first time that PM exposure significantly inhibits various beneficial functions of endometrial stem cells, such as their self-renewal, transdifferentiation, and migratory capacities, in vitro and in vivo through the PM target gene SERPINB2, which has recently been shown to be involved in multiple stem cell functions. In addition, the PM-induced inhibitory effects on the beneficial functions of endometrial stem cells were significantly diminished by SERPINB2 depletion. Our findings may facilitate the development of promising therapeutic strategies for improving reproductive outcomes in infertile women.

Airborne pollutants may reduce female fertility through their debilitating effects on the stem cells that maintain the endometrium, the interior lining of the uterus. Recent evidence suggests that toxic byproducts from fossil fuels known as ‘particulate matter’ represent a danger to women’s reproductive health. South Korean researchers led by Ji-Won Jung, Korea Centers for Disease Control and Prevention, and In-Sun Hong, Gachon University, Incheon, have investigated this risk by exposing cultured human endometrial stem cells to diesel-derived particulate matter. These stem cells normally maintain the endometrium, allowing embryonic implantation to take place, but exposure to particulate matter greatly impaired the cells’ regenerative function. Mice exposed to particulate matter exhibited similar impairments of endometrial maintenance. The researchers identified a molecular pathway associated with this response that could guide development of fertility-restoring treatments.

The Spiny Mouse—A Menstruating Rodent to Build a Bridge From Bench to Bedside

Menstruation, the cyclical breakdown of the uterine lining, is arguably one of evolution's most mysterious reproductive strategies. The complexity and rarity of menstruation within the animal kingdom is undoubtedly a leading contributor to our current lack of understanding about menstrual function and disorders. In particular, the molecular and environmental mechanisms that drive menstrual and fertility dysregulation remain ambiguous, owing to the restricted opportunities to study menstruation and model menstrual disorders in species outside the primates. The recent discovery of naturally occurring menstruation in the Egyptian spiny mouse (Acomys cahirinus) offers a new laboratory model with significant benefits for prospective research in women's health. This review summarises current knowledge of spiny mouse menstruation, with an emphasis on spiral artery formation, inflammation and endocrinology. We offer a new perspective on cycle variation in menstrual bleeding between individual animals, and propose that this is indicative of fertility success. We discuss how we can harness our knowledge of the unique physiology of the spiny mouse to better understand vascular remodelling and its implications for successful implantation, placentation, and foetal development. Our research suggests that the spiny mouse has the potential as a translational research model to bridge the gap between bench to bedside and provide improved reproductive health outcomes for women.

Solving the Puzzle: What Is the Role of Progestogens in Neovascularization?

Ovarian sex steroids can modulate new vessel formation and development, and the clarification of the underlying mechanism will provide insight into neovascularization-related physiological changes and pathological conditions. Unlike estrogen, which mainly promotes neovascularization through activating classic post-receptor signaling pathways, progesterone (P4) regulates a variety of downstream factors with angiogenic or antiangiogenic effects, exerting various influences on neovascularization. Furthermore, diverse progestins, the synthetic progesterone receptor (PR) agonists structurally related to P4, have been used in numerous studies, which could contribute to unequal actions. As a result, there have been many conflicting observations in the past, making it difficult for researchers to define the exact role of progestogens (PR agonists including naturally occurring P4 and synthetic progestins). This review summarizes available evidence for progestogen-mediated neovascularization under physiological and pathological circumstances, and attempts to elaborate their functional characteristics and regulatory patterns from a comprehensive perspective.

The influence of biological and lifestyle factors on circulating cell-free DNA in blood plasma

Research and clinical use of circulating cell-free DNA (cirDNA) is expanding rapidly; however, there remain large gaps in our understanding of the influence of lifestyle and biological factors on the amount of cirDNA present in blood. Here, we review 66 individual studies of cirDNA levels and lifestyle and biological factors, including exercise (acute and chronic), alcohol consumption, occupational hazard exposure, smoking, body mass index, menstruation, hypertension, circadian rhythm, stress, biological sex and age. Despite technical and methodological inconsistences across studies, we identify acute exercise as a significant influence on cirDNA levels. Given the large increase in cirDNA induced by acute exercise, we recommend that controlling for physical activity prior to blood collection is routinely incorporated into study design when total cirDNA levels are of interest. We also highlight appropriate selection and complete reporting of laboratory protocols as important for improving the reproducibility cirDNA studies and ability to critically evaluate the results.

Stem cell-based therapy for ameliorating intrauterine adhesion and endometrium injury

Intrauterine adhesion refers to endometrial repair disorders which are usually caused by uterine injury and may lead to a series of complications such as abnormal menstrual bleeding, recurrent abortion and secondary infertility. At present, therapeutic approaches to intrauterine adhesion are limited due to the lack of effective methods to promote regeneration following severe endometrial injury. Therefore, to develop new methods to prevent endometrial injury and intrauterine adhesion has become an urgent need. For severely damaged endometrium, the loss of stem cells in the endometrium may affect its regeneration. This article aimed to discuss the characteristics of various stem cells and their applications for uterine tissue regeneration.

PPP2R2A affects embryonic implantation by regulating the proliferation and apoptosis of Hu sheep endometrial stromal cells

Embryonic implantation is a complex reproductive physiological process in mammals. Although several endometrial proteins affecting embryonic implantation have been reported in the past, there are still potential endometrial proteins that have been neglected, and their specific regulatory mechanisms are unclear. This study demonstrated that protein phosphatase 2A regulatory subunit B55α (PPP2R2A) served as a novel regulator in medication of sheep embryonic implantation in vitro. Our results showed that sheep PPP2R2A encoded 447 amino acids and shared 91.74%-92.36% amino acid sequences with its orthologs compared with other species. Meanwhile, PPP2R2A was widely expressed in sheep uterine tissues, and it could regulate the expression levels of key regulators of embryonic implantation in endometrial stromal cells (ESCs). Knockdown of PPP2R2A significantly inhibited cell proliferation by blocking cell cycle transfer G0/G1 into S phase accompanied by downregulation of CDK2, CDK4, CCND1, CCNE1 and upregulation of P21. In contrast to PPP2R2A overexpression, PPP2R2A interference greatly promoted cell apoptosis and the expression of BAX, CASP3, CASP9 and BAX/BCL-2. Taken together, these results suggest that PPP2R2A, as a novel regulatory factor, affects embryonic implantation via regulating the proliferation and apoptosis of Hu sheep ESCs in vitro.

The Absence of Extracellular Cold-Inducible RNA-Binding Protein (eCIRP) Promotes Pro-Angiogenic Microenvironmental Conditions and Angiogenesis in Muscle Tissue Ischemia

Extracellular Cold-inducible RNA-binding protein (eCIRP), a damage-associated molecular pattern, is released from cells upon hypoxia and cold-stress. The overall absence of extra- and intracellular CIRP is associated with increased angiogenesis, most likely induced through influencing leukocyte accumulation. The aim of the present study was to specifically characterize the role of eCIRP in ischemia-induced angiogenesis together with the associated leukocyte recruitment. For analyzing eCIRPs impact, we induced muscle ischemia via femoral artery ligation (FAL) in mice in the presence or absence of an anti-CIRP antibody and isolated the gastrocnemius muscle for immunohistological analyses. Upon eCIRP-depletion, mice showed increased capillary/muscle fiber ratio and numbers of proliferating endothelial cells (CD31⁺/CD45⁻/BrdU⁺). This was accompanied by a reduction of total leukocyte count (CD45⁺), neutrophils (MPO⁺), neutrophil extracellular traps (NETs) (MPO⁺CitH3⁺), apoptotic area (ascertained via TUNEL assay), and pro-inflammatory M1-like polarized macrophages (CD68⁺/MRC1⁻) in ischemic muscle tissue. Conversely, the number of regenerative M2-like polarized macrophages (CD68⁺/MRC1⁺) was elevated. Altogether, we observed that eCIRP depletion similarly affected angiogenesis and leukocyte recruitment as described for the overall absence of CIRP. Thus, we propose that eCIRP is mainly responsible for modulating angiogenesis via promoting pro-angiogenic microenvironmental conditions in muscle ischemia.

The effect of absent blood flow on the zebrafish cerebral and trunk vasculature

The role of blood flow in vascular development is complex and context-dependent. In this study, we quantify the effect of the lack of blood flow on embryonic vascular development on two vascular beds, namely the cerebral and trunk vasculature in zebrafish. We perform this by analysing vascular topology, endothelial cell (EC) number, EC distribution, apoptosis, and inflammatory response in animals with normal blood flow or absent blood flow. We find that absent blood flow reduced vascular area and EC number significantly in both examined vascular beds, but the effect is more severe in the cerebral vasculature, and severity increases over time. Absent blood flow leads to an increase in non-EC-specific apoptosis without increasing tissue inflammation, as quantified by cerebral immune cell numbers and nitric oxide. Similarly, while stereotypic vascular patterning in the trunk is maintained, intra-cerebral vessels show altered patterning, which is likely to be due to vessels failing to initiate effective fusion and anastomosis rather than sprouting or path-seeking. In conclusion, blood flow is essential for cellular survival in both the trunk and cerebral vasculature, but particularly intra-cerebral vessels are affected by the lack of blood flow, suggesting that responses to blood flow differ between these two vascular beds.

Vascular biology of uterine fibroids: connecting fibroids and vascular disorders

Fibroids are benign tumors caused by the proliferation of myometrial smooth muscle cells in the uterus that can lead to symptoms such as abdominal pain, constipation, urinary retention, and infertility. While traditionally thought of as a disease process intrinsic to the uterus, accumulating evidence suggests that fibroid growth may be linked with the systemic vasculature system, although cell-intrinsic factors are certainly of principal importance in their inception. Fibroids are associated with essential hypertension and preeclampsia, as well as atherosclerosis, for reasons that are becoming increasingly elucidated. Factors such as the renin-angiotensin-aldosterone system, estrogen, and endothelial dysfunction all likely play a role in fibroid pathogenesis. In this review, we lay out a framework for reconceptualizing fibroids as a systemic vascular disorder, and discuss how pharmaceutical agents and other interventions targeting the vasculature may aid in the novel treatment of fibroids.

Total and endothelial cell-derived cell-free DNA in blood plasma does not change during menstruation

Assays measuring cell-free DNA (cfDNA) in blood have widespread potential in modern medicine. However, a comprehensive understanding of cfDNA dynamics in healthy individuals is required to assist in the design of assays that maximise the signal driven by pathological changes, while excluding fluctuations that are part of healthy physiological processes. The menstrual cycle involves major remodelling of endometrial tissue and associated apoptosis, yet there has been little investigation of the impact of the menstrual cycle on cfDNA levels. Paired plasma samples were collected from 40 healthy women on menstruating (M) and non-menstruating (NM) days of their cycle. We measured total cfDNA by targeting ALU repetitive sequences and measured endothelial-derived cfDNA by methylation-specific qPCR targeting an endothelium-unique unmethylated CDH5 DNA region. CfDNA integrity and endothelial cfDNA concentration, but not total cfDNA, are consistent across time between NM and M. No significant changes in total (ALU-115 p = 0.273; ALU-247 p = 0.385) or endothelial cell specific (p = 0.301) cfDNA were observed, leading to the conclusion that menstrual status at the time of diagnostic blood collection should not have a significant impact on the quantitation of total cfDNA and methylation-based cancer assays.

Activation of Blood Vessel Development in Endometrial Stromal Cells In Vitro Cocultured with Human Peri-Implantation Embryos Revealed by Single-Cell RNA-Seq

In humans, the maternal endometrium participates in the physical and physiological interaction with the blastocyst to begin implantation. A bidirectional crosstalk is critical for normal implantation and then a successful pregnancy. While several studies have used animal models or cell lines to study this step, little knowledge was acquired to address the role of endometrial cells in humans. Here, we analyzed single-cell sequencing data from a previous study including 24 non-coculture endometrial stromal cells (EmSCs) and 57 EmSCs after coculture with embryos. We further explored the transcriptomic changes in EmSCs and their interactions with trophoblast cells after coculture. Differentially expressed gene (DEG) analysis showed 1783 upregulated genes and 569 downregulated genes in the cocultured embryos. Weight gene coexpression network and gene ontology analysis of these DEGs showed a higher expression of RAMP1, LTBP1, and LRP1 in EmSCs after coculture, indicating the enrichment of biological processes in blood vessel development and female pregnancy. These data imply that EmSCs start blood vessel development at the implantation stage. Compared with endometrium data in vivo at the implantation window, key pathways including epithelial cell development and oxygen response were involved at this stage. Further analysis using CellphoneDB shed light on the interactions between EmSCs and embryonic trophoblasts, suggesting the important role of integrins and fibroblast growth factor pathways during implantation. Taken together, our work reveals the synchronization signaling and pathways happening at the implantation stage involving the acquisition of receptivity in EmSCs and the interaction between EmSCs and trophoblast cells.

Absence of Cold-Inducible RNA-Binding Protein (CIRP) Promotes Angiogenesis and Regeneration of Ischemic Tissue by Inducing M2-Like Macrophage Polarization

Cold-inducible RNA-binding protein (CIRP) is an intracellular RNA-chaperone and extracellular promoter of inflammation, which is increasingly expressed and released under conditions of hypoxia and cold stress. The functional relevance of CIRP for angiogenesis and regeneration of ischemic muscle tissue has never been investigated and is the topic of the present study. We investigated the role of CIRP employing CIRP deficient mice along with a hindlimb model of ischemia-induced angiogenesis. 1 and 7 days after femoral artery ligation or sham operation, gastrocnemius muscles of CIRP-deficient and wildtype mice were isolated and processed for (immuno-) histological analyses. CIRP deficient mice showed decreased ischemic tissue damage as evidenced by Hematoxylin and Eosin staining, whereas angiogenesis was enhanced as demonstrated by increased capillary/muscle fiber ratio and number of proliferating endothelial (CD31⁺/BrdU⁺) cells on day 7 after surgery. Moreover, CIRP deficiency resulted in a reduction of total leukocyte count (CD45⁺), neutrophils (myeloperoxidase, MPO⁺), neutrophil extracellular traps (NETs) (MPO⁺/CitH3⁺), and inflammatory M1-like polarized macrophages (CD68⁺/MRC1^-), whereas the number of tissue regenerating M2-like polarized macrophages (CD68⁺/MRC1^-) was increased in ischemic tissue samples. In summary, we show that the absence of CIRP ameliorates angiogenesis and regeneration of ischemic muscle tissue, most likely by influencing macrophage polarization in direction to regenerative M2-like macrophages.

Kisspeptin/Kiss1r system and angiogenic and immunological mediators at the maternal-fetal interface of domestic cats

The Kisspeptin/Kiss1r system is a key regulator of reproduction by stimulating gonadotrophin-releasing hormone and luteinizing hormone release, and in vitro studies have shown that Kisspeptin can modulate angiogenesis and immune function, factors that are also essential for reproduction However, there are no studies on the expression of Kisspeptin/Kiss1r at the maternal-fetal interface in domestic cats and its relationship with angiogenic and immunological mediators. Thus, our objective was to evaluate the spatiotemporal expression profile of Kisspeptin/Kiss1r and angiogenic and immunological mediators in the uterus and placenta of domestic cats during pregnancy. Uterus and placenta samples were collected from cats in mid pregnancy (N = 6) and late pregnancy (N = 6), in addition to uterus from non-pregnant cats in diestrus (N = 7), to evaluate protein and gene expression of kisspeptin (Kiss1), kisspeptin receptor (Kiss1r), vascular endothelial growth factor (VEGF), tyrosine kinase receptor (Flk-1), placental growth factor (PLGF), interferon gamma (INFγ), migration inhibiting factor (MIF), tumor necrosis factor (TNFα), interleukins (IL6 and IL10) by immunohistochemistry and quantitative polymerase chain reaction. Pregnancy increased the uterine expression of Kiss1 and Kiss1r, especially at the late pregnancy, in addition to upregulating INFy, MIF, Vegf, Il10, and Tnf and downregulating Plgf. Higher placental expression of Kiss1r and Plgf mRNA occurred at the late pregnancy, while the expression of Kiss1, VEGF, Flk-1, INFy, TNFα, Il6, and IL10 was higher in the mid of pregnancy. A positive correlation between Kiss1 and Tnf was observed in the placenta, while Kiss1r had a negative correlation with Infγ, Il6, and Il10. The findings reveal that Kisspeptin/Kiss1r and angiogenic and immunological mediators at the maternal-fetal interface of pregnant cat have a gene correlation and are modulated by the gestational age. These data suggest possible functional links of Kisspeptin in placental angiogenesis and immunology.

The Role of TNF-α and Anti-TNF-α Agents during Preconception, Pregnancy, and Breastfeeding

Tumor necrosis factor-alpha (TNF-α) is a multifunctional Th1 cytokine and one of the most important inflammatory cytokines. In pregnancy, TNF-α influences hormone synthesis, placental architecture, and embryonic development. It was also shown that increased levels of TNF-α are associated with pregnancy loss and preeclampsia. Increased TNF-α levels in complicated pregnancy draw attention to trophoblast biology, especially migratory activity, syncytialisation, and endocrine function. Additionally, elevated TNF-α levels may affect the maternal-fetal relationship by altering the secretory profile of placental immunomodulatory factors, which in turn affects maternal immune cells. There is growing evidence that metabolic/pro-inflammatory cytokines can program early placental functions and growth in the first trimester of pregnancy. Furthermore, early pregnancy placenta has a direct impact on fetal development and maternal immune system diseases that release inflammatory (e.g., TNF-α) and immunomodulatory factors, such as chronic inflammatory rheumatic, gastroenterological, or dermatological diseases, and may result in an abnormal release of cytokines and chemokines in syncytiotrophoblasts. Pregnancy poses a challenge in the treatment of chronic disease in patients who plan to have children. The activity of the disease, the impact of pregnancy on the course of the disease, and the safety of pharmacotherapy, including anti-rheumatic agents, in pregnancy should be considered.

Steroid hormones and first trimester vascular remodeling

Successful implantation and placentation require neoangiogenesis and the remodeling of the uterine spiral arteries. Progesterone and estradiol control various of the placental functions, but their role in vascular remodeling remains controversial. Therefore, this chapter aims to summarize the current knowledge regarding the role of steroid hormones in the uteroplacental vascular remodeling during the first trimester of gestation.

An update on platelet-rich plasma (PRP) therapy in endometrium and ovary related infertilities: clinical and molecular aspects

Administration of platelet-rich plasma (PRP) is one of the well-recommended strategies for the treatment of endometrium- and ovary-associated infertility. Due to the autologous source of PRP, minimal risks for disease transmission and immunogenic and allergic responses are expected in this method. Despite the extensive use of PRP in medicine, its precise mechanism of action in endometrial and ovarian tissues is still unknown. Nevertheless, the induction of cell proliferation, chemotaxis, regeneration, extracellular matrix synthesis, remodeling, angiogenesis, and epithelialization are the main pathways for PRP to affect female reproductive organs. Given the promising results of previous studies, it is necessary to standardize PRP preparation protocols for different therapeutic purposes and also clearly determine appropriate inclusion and exclusion criteria for recruiting patients. In the current review, we presented a summary of studies on PRP therapy for endometrium- and ovary-associated infertility with a focus on the possible mechanisms by which PRP enhances endometrial receptivity and regenerates ovarian function.Abbreviations: PRP: platelet-rich plasma; ART: assisted reproductive technology; POF: premature ovarian failure; TGF: transforming growth factors; PDGF: platelet-derived growth factors; IGF-I: insulin-like growth factor-1; HGF: hepatocyte growth factor; EGF: epidermal growth factor; FGF: fibroblast growth factor; VEGF: vascular endothelial growth factor; ADP: adenosine diphosphate, ATP: adenosine triphosphate; PDGF: platelet-derived growth factor; COX2: cyclooxygenase-2; TP53: tumor protein 53; ER-α: estrogen receptors alpha; ER-β: estrogen receptors beta; PR: progesterone receptor; RIF: recurrent implantation failure; G-CSF: granulocyte colony-stimulating factor; iNOS: inducible nitric oxide synthase; NF-kβ: nuclear factor kappa beta; MMPs: matrix metalloproteinases; Col1a1: collagen type I alpha 1; IL: interleukin; FSH: follicle-stimulating hormone; AMH: anti-Mullerian hormone; GDF-9: growth differentiation factor 9.

Application of Ligilactobacillus salivarius CECT5713 to Achieve Term Pregnancies in Women with Repetitive Abortion or Infertility of Unknown Origin by Microbiological and Immunological Modulation of the Vaginal Ecosystem

In this study, the cervicovaginal environment of women with reproductive failure (repetitive abortion, infertility of unknown origin) was assessed and compared to that of healthy fertile women. Subsequently, the ability of Ligilactobacillus salivarius CECT5713 to increase pregnancy rates in women with reproductive failure was evaluated. Vaginal pH and Nugent score were higher in women with reproductive failure than in fertile women. The opposite was observed regarding the immune factors TGF-β 1, TFG-β 2, and VEFG. Lactobacilli were detected at a higher frequency and concentration in fertile women than in women with repetitive abortion or infertility. The metataxonomic study revealed that vaginal samples from fertile women were characterized by the high abundance of Lactobacillus sequences, while DNA from this genus was practically absent in one third of samples from women with reproductive failure. Daily oral administration of L. salivarius CECT5713 (~9 log₁₀ CFU/day) to women with reproductive failure for a maximum of 6 months resulted in an overall successful pregnancy rate of 56%. The probiotic intervention modified key microbiological, biochemical, and immunological parameters in women who got pregnant. In conclusion, L. salivarius CECT5713 has proved to be a good candidate to improve reproductive success in women with reproductive failure.

Biomaterial strategies to replicate gynecological tissue

Properties of native tissue can inspire biomimetic in vitro models of gynecological disease.

Gonadotropin-releasing hormone analogs: Mechanisms of action and clinical applications in female reproduction

Extra-hypothalamic GnRH and extra-pituitary GnRH receptors exist in multiple human reproductive tissues, including the ovary, endometrium and myometrium. Recently, new analogs (agonists and antagonists) and modes of GnRH have been developed for clinical application during controlled ovarian hyperstimulation for assisted reproductive technology (ART). Additionally, the analogs and upstream regulators of GnRH suppress gonadotropin secretion and regulate the functions of the reproductive axis. GnRH signaling is primarily involved in the direct control of female reproduction. The cellular mechanisms and action of the GnRH/GnRH receptor system have been clinically applied for the treatment of reproductive disorders and have widely been introduced in ART. New GnRH analogs, such as long-acting GnRH analogs and oral nonpeptide GnRH antagonists, are being continuously developed for clinical application. The identification of the upstream regulators of GnRH, such as kisspeptin and neurokinin B, provides promising potential to develop these upstream regulator-related analogs to control the hypothalamus-pituitary-ovarian axis.

Effects of Erbuzhuyu Decoction Combined with Acupuncture on Endometrial Receptivity Are Associated with the Expression of miR-494-3p

Background/Aim

Erbuzhuyu decoction (EBZYD) is a traditional Chinese medicine (TCM) formula and has been used in infertility treatment. Meanwhile, acupuncture is also used to treat female infertility. However, it is unclear whether EBZYD combined with acupuncture has better therapeutic effect. The aim of this study was to explore the effect of EBZYD combined with acupuncture and investigate its mechanism in superovulation mice.

Methods

The mice received the treatment of EBZYD, acupuncture, EBZYD combined with acupuncture, or miR-494-3p agomir combined with EBZYD and acupuncture. The blastocysts' number, endometrial microstructure, and endometrial thickness were observed, followed by the detection of endometrial receptivity-related factors, PI3K/Akt/mTOR pathway-related proteins, and miR-494-3p expression using quantitative real-time polymerase chain reaction (qRT-PCR) or western blot. Luciferase reporter assay was performed to confirm the targeting relationship between HOXA10 and miR-494-3p.

Results

EBZYD combined with acupuncture treatment could increase the number of blastocysts, pinopodes, endometrial thickness, and the expression of endometrial receptivity-related factors, and the treatment effect of EBZYD combined with acupuncture was better than EBZYD or acupuncture alone. In addition, EBZYD combined with acupuncture treatment activated PI3K/Akt/mTOR pathway and inhibited the expression of miR-494-3p. HOXA10 is one of the target genes of miR-494-3p. Overexpression of miR-494-3p reversed the therapeutic effect of EBZYD combined with acupuncture and suppressed the expression of HOXA10 and the activity of PI3K/Akt/mTOR pathway.

Conclusion

This study suggests that EBZYD combined with acupuncture could improve endometrial receptivity in superovulation mice via miR-494-3p/HOXA10 axis.

Biomaterials for Bioprinting Microvasculature

Microvasculature functions at the tissue and cell level, regulating local mass exchange of oxygen and nutrient-rich blood. While there has been considerable success in the biofabrication of large- and small-vessel replacements, functional microvasculature has been particularly challenging to engineer due to its size and complexity. Recently, three-dimensional bioprinting has expanded the possibilities of fabricating sophisticated microvascular systems by enabling precise spatiotemporal placement of cells and biomaterials based on computer-aided design. However, there are still significant challenges facing the development of printable biomaterials that promote robust formation and controlled 3D organization of microvascular networks. This review provides a thorough examination and critical evaluation of contemporary biomaterials and their specific roles in bioprinting microvasculature. We first provide an overview of bioprinting methods and techniques that enable the fabrication of microvessels. We then offer an in-depth critical analysis on the use of hydrogel bioinks for printing microvascularized constructs within the framework of current bioprinting modalities. We end with a review of recent applications of bioprinted microvasculature for disease modeling, drug testing, and tissue engineering, and conclude with an outlook on the challenges facing the evolution of biomaterials design for bioprinting microvasculature with physiological complexity.

Long non-coding RNA366.2 controls endometrial epithelial cell proliferation and migration by upregulating WNT6 as a ceRNA of miR-1576 in sheep uterus

Long non-coding RNAs (lncRNAs) play an important regulatory role in mammalian fecundity. Currently, most studies are primarily concentrated on ovarian lncRNAs, ignoring the influence of uterine lncRNAs on the fecundity of female sheep. In this study, we found a higher density of uterine glands and endometrial microvessel density (MVD) in high prolificacy group of Hu sheep compared to low prolificacy groups (p < 0.05) as well as an increased level of serum placental growth factor (PLGF). Hundreds of differentially expressed (DE) lncRNAs were identified in Hu sheep with different fecundity by RNA sequencing (RNA-seq), and their targets were enriched in some signaling pathways involved in endometrial functions, such as the estrogen signaling pathway, nuclear factor kappa B (NF-κB) signaling pathway, oxytocin signaling pathway, and Wnt signaling pathway. Furthermore, the underlying mechanisms of competitive endogenous RNA (ceRNA) of lncRNA366.2-miR-1576- WNT6 were determined by bioinformatics analysis. Functionally, our results indicated that lncRNA366.2 promoted endometrial epithelial cell (EEC) proliferation, migration, and growth factor expression by sponging miR-1576 to upregulate WNT6 expression and activate the Wnt/β-catenin pathway. Taken together, our research indicated the regulatory mechanism of the lncRNA366.2-miR-1576-WNT6 in EEC proliferation and migration. Furthermore, this study provides a new theoretical reference for the identification of candidate genes related to fecundity.