Repairing and Regenerating Injured Endometrium Methods

Comprehensive single-cell transcriptome analysis of autologous platelet-rich plasma therapy on human thin endometrium

Therapeutics for thin endometrium (TE) have emerged, with autologous platelet-rich plasma (PRP) therapy gaining significant attention. In the present study, ten eligible TE patients were recruited for PRP infusion. Endometrial tissue biopsies collected before and after PRP therapy (paired samples) were subjected to single-cell RNA sequencing (scRNA-seq). Additionally, haematoxylin and eosin (HE) and immunohistochemistry (IHC) were employed to validate changes in protein markers. The results demonstrated PRP therapy increased the average endometrial thickness in these patients. Cellular trajectory reconstruction analysis using gene counts and expression (CytoTRACE) scores indicated that high-stemness cells were more enriched in proliferating stromal cells (pStr) or stromal cells (Str) in post-PRP samples, while greater stemness was observed in glandular epithelial cells (GE) and luminal epithelial cells (LE). Gene set variation analysis (GSVA) revealed significant differences in mesenchymal‒epithelial transition (MET)-related gene signature scores between paired samples. Furthermore, an increased number of macrophages, particularly M1-type macrophages, was detected in post-PRP samples. As the first study to investigate the effects of PRP therapy via transcriptomic analysis, our findings suggest PRP therapy may enhance high-stemness, stimulate MET, and boost macrophage function. These insights contribute to a better understanding of the mechanisms underlying PRP therapy and its potential in treating TE patients.

Human embryonic stem cell-derived immunity-and-matrix-regulatory cells promote endometrial repair and fertility restoration in IUA rats

BACKGROUND

Intrauterine adhesion (IUA) refers to endometrial fibrosis resulting from endometrial injury and infection. In promoting the repair of the endometrium, mesenchymal stem cells therapy has shown great potential. However, adult-derived mesenchymal stem cells (MSCs) are associated with several challenges, including invasive manipulation, susceptibility to contamination, and low proliferative capacity. Immunity-and-matrix-regulatory cells (IMRCs) derived from human embryonic stem cells exhibit enhanced immunomodulatory and anti-fibrotic capabilities. Despite their success in treating lung injury and fibrosis, membranous nephropathy, and acute liver failure, their therapeutic potential in IUA remains undetermined.

METHODS

TGF-β1-induced human endometrial stromal cells (HESCs) were utilized to construct the IUA cell model and were treated with IMRCs conditioned medium. Morphological changes in the cells were observed, and RT-qPCR and Western blot analyses were employed to detect the expression of relevant markers during the process of epithelial-mesenchymal transition (EMT) in vitro. The IUA rat model was established using the dual injury method and subsequently treated with intrauterine infusion of IMRCs. HE and Masson staining were used to assess endometrial damage, repair and the extent of fibrosis. Fertility assays were performed to compare the effectiveness of IMRCs and umbilical cord mesenchymal stem cells (UCMSCs) in improving endometrial function in IUA rats. Sequencing analysis of IMRCs-derived exosomes (Exos) was conducted to identify specific miRNAs and the pathways they target.

RESULTS

TGF-β1 treatment induced HESCs to undergo fibrotic transformation and express fibrosis-related markers, while treatment with IMRCs conditioned medium inhibited TGF-β1-induced fibrosis. IUA rats were treated with intrauterine infusion of IMRCs. IMRCs facilitated the repair of damaged endometrium, restored the structure of the uterine cavity, and reduced collagen deposition. IMRCs reversed the process of endometrial EMT in rats with IUA, upregulated the expression of epithelial markers, and downregulated the expression of mesenchymal markers. IMRCs further exerted antifibrotic effects by reducing inflammatory responses. Fertility recovery in rats receiving intrauterine infusion of IMRCs was superior to that in rats receiving intrauterine infusion of UCMSCs. Specific miRNAs in Exos, including miR-27b-3p, miR-145-5p, and miR-16-5p, directly target Smad2, inhibit Smad2 phosphorylation, and modulate the TGF-β/Smad pathway.

CONCLUSIONS

Our study demonstrated that IMRCs inhibited TGF-β1-induced fibrosis in HESCs, suppressed the EMT process ex vivo, reduced the inflammatory response, and reversed endometrial damage and fibrosis in IUA rats. IMRCs exerted their effects through the paracrine pathway, with specific miRNAs in Exos downregulating the TGF-β/Smad signaling pathway to inhibit uterine endometrial fibrosis. IMRCs provide a new direction for the treatment of IUA.

Development of regenerative therapies targeting fibrotic endometrium in intrauterine adhesion or thin endometrium to restore uterine function

Intrauterine adhesions (IUA) and thin endometrium (TE) represent significant challenges in human reproduction. The condition arises frequently from damage to the endometrial basal layer, leading to fibrous tissue replacing the functional endometrium and impairing the uterus's ability to accept embryo implantation. Conventional treatments, mainly including hysteroscopic adhesiolysis and estrogen therapies, have shown limited success, particularly in severe cases. Regenerative medicine, with its focus on stem cell-based therapies and biomaterials, offers a promising avenue for restoring endometrial function and structure. This review synthesizes the current landscape of endometrial regeneration, focusing on the therapeutic potential of stem cells, the supportive role of biomaterials, and the importance of understanding molecular mechanisms to develop effective strategies for reconstruction of endometrial functional and fertility restoration.

Development and functional evaluation of recombinant type III collagen intrauterine implant gel

Intrauterine adhesion (IUA) is a prevalent complication arising from uterine surgery, significantly impacting women's fertility and overall quality of life. The conventional clinical approach involves hysteroscopic separation of uterine adhesions, though this method poses operational challenges and carries risks of postoperative re-adhesion. Alternatively, the intraoperative placement of intrauterine devices or support balloons can act as a physical barrier to prevent adhesion formation. However, its effectiveness is limited and it may result in secondary damage to the endothelial tissue. To tackle these challenges, we have engineered a temperature-responsive hydrogel incorporating Pluronic HP407/HP188 pharmaceutical excipients and recombinant type III collagen (rCol III) as a bioactive element. Upon in situ injection into the uterine cavity, this hydrogel transitions from a sol-gel phase to a gel in response to body temperature changes, thereby minimizing nonspecific distribution and prolonging the duration of treatment. In vitro studies demonstrate that rCol III temperature-responsive hydrogels exhibit favorable biocompatibility, exhibit a recruitment effect on human endometrial stromal cells, suppress the expression of the fibrotic factor transforming growth factor beta 1 and promote angiogenesis. To evaluate its efficacy in preventing IUA via in vivo experiments, we employed sexually mature female rats for IUA modeling and compared its performance with a commercially available product, cross-linked sodium hyaluronate gel. The results indicate that rCol III temperature-responsive hydrogels significantly enhance retention at the injury site, substantially promote endometrial regeneration, augment endometrial blood supply and reduce abnormal fibrin deposition. This study suggests that rCol III temperature-responsive hydrogels can effectively prevent post-surgical uterine adhesions, highlighting their potential as a promising adhesion prevention strategy.

Defining optimal electrospun membranes to enhance biological activities of human endometrial MSCs

Introduction

Human endometrial mesenchymal stem cells (H-EMSCs) can inhibit endometrial fibrosis and repair damaged endometrium. However, direct cell injection into dam-aged endometrium shows limited cell survival. Cell seeding onto biomaterial-based electrospun membranes could improve H-EMSCs' survival and prolong their stay at the damaged endometrium. Polycaprolactone (PCL), silk fibroin (SF) and hyaluronic acid (HA) are synthetic or natural biomaterials used by the biomedicine field, however, their effects on the biological activities of H-EMSCs remain unclear.

Methods

In this study, CD90+CD73+CD45- H-EMSCs were extracted from human endometrium and H-EMSCs showed enhanced adhesion, proliferation on PCL-HA vs. PCL, PCL-SF, establishing the potential of the composite to address cell survival issues.

Results

H-EMSCs cultured on PCL-HA showed decreased IL-6 gene expression and increased IL-10, VEGFA, TGF-β gene expression vs. PCL-SF, establishing the potential to create a favorable micro-environment for generating vascularized endometrial tissues. PCL, PCL-SF, PCL-HA all supported CD90 and Meflin expression of the seeded H-EMSCs, establishing PCL as a platform to form enhanced biomaterial composites for endometrial repair in the future.

Discussion

This study provided significant evidence sup-porting the potential of appropriately tailored composites of PCL and HA to moder-ate inflammation and wound-healing, which can be applied for endometrial tissue repair and regeneration.

Lower expression of colony-stimulating factor 2, an embryokine, in the endometrial epithelium of old cows

Context Infertility increases with age in various animals, including cows, owing to unknown mechanisms. The glandular and luminal epithelia of the bovine uterus synthesise and secrete colony-stimulating factor 2 (CSF2), which is a well-studied embryokine. We recently reported the possibility of fibrosis in the uteri of old cows. However, the relationship between CSF2 expression and fibrosis has not yet been clarified. Aims We tested the hypothesis that the endometrial epithelia of old cows have lower CSF2 expression compared to in heifers, and that myofibroblasts [alpha-smooth muscle actin (αSMA)-positive fibroblasts] increase near the epithelium of old cows. Methods We collected caruncle and intercaruncle samples from post-pubertal, growing, nulliparous heifers (n =6; 24.7±1.3months old) and old multiparous cows (n =6; 128.5±15.4months old). We analysed mRNA and protein expression, along with fluorescent immunohistochemistry for CSF2, anti-collagen type IV, anti-Müllerian hormone type 2 receptor, and anti-αSMA. Key results Quantitative reverse transcription polymerase chain reaction and western blot analysis revealed lower CSF2 expression in the caruncle and intercaruncle of old cows than in young heifers. Fluorescence microscopy using the same antibodies and anti-collagen type IV, anti-Müllerian hormone type 2 receptor, and anti-αSMA antibodies showed increased fibroblasts and αSMA signals near the epithelium of old cows compared to young heifers. Conclusion CSF2 expression was lower in endometrial epithelia of old cows compared to those in heifers, and myofibroblasts increased near the epithelia of old cows. Implications Lower CSF2 may play an important role in age-related infertility.

Association between first-trimester subchorionic hematoma and pregnancy loss before 20 weeks of gestation in singleton pregnancies

To evaluate the association between a first-trimester subchorionic hematoma (SCH) and pregnancy loss before 20 weeks of gestation in singleton pregnancies. We conducted a retrospective cohort study of singleton pregnancies from January to December 2021. All patients had routine first-trimester ultrasound scans and were followed up for pregnancy outcomes. We compared pregnancy loss rates before 20 weeks in women with and without SCH and analyzed risk factors using logistic regression. Out of 1,144 singleton pregnancies, 559 (48.9%) had SCH. Women with SCH had higher rates of vaginal bleeding (38.1 vs. 23.2%, P < 0.001). SCH was independently associated with miscarriage before 20 weeks (adjusted OR 1.94, 95% CI 1.19-3.15). Earlier SCH diagnosis increased miscarriage risk (adjusted OR 2.71 for diagnosis before 7 weeks, 95% CI 1.45-5.07). SCH size was not linked to pregnancy loss, but "large" SCH increased placental abruption risk (adjusted OR 5.03, 95% CI 1.20-21.11). Dydrogesterone use appeared protective against miscarriage (adjusted OR 0.28, 95% CI 0.15-0.52). First-trimester SCH is associated with an increased risk of miscarriage before 20 weeks. Large SCHs increase the risk of placental abruption, while dydrogesterone use may reduce miscarriage risk.

A multicentre, randomized, double-blind, placebo-controlled trial of topical oestradiol gel for endometrial regeneration after induced abortion

STUDY QUESTION

Is topical oestradiol gel effective in promoting endometrial regeneration after a surgical abortion?

SUMMARY ANSWER

Topical oestradiol gel is effective in promoting endometrial regeneration after a surgical abortion with few side-effects.

WHAT IS KNOWN ALREADY

Oestrogen is effective in promoting endometrial regeneration. Transdermal oestrogen has been widely used in clinical practice for endometrial regeneration after induced abortion, but high-level evidence is limited.

STUDY DESIGN, SIZE, DURATION

We conducted a multicentre, superiority, randomized, double-blind, placebo-controlled trial. Between 9 March 2022 and 21 February 2023, 200 women were assigned in a 1:1 ratio to receive either oestradiol gel (treatment) and or oestradiol gel simulant (control) for 28 days. The participants were scheduled to have their endometrial thickness (mm) measured by ultrasonographic scan at 21-23 days post-abortion. The trial was blinded for participants, investigators, medical staff, and statistical analysts until final unblinding.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Participants were women undergoing induced abortion within 10 weeks of gestation. A total of 200 participants were enrolled, with 100 in each group. Eighty-eight (88%) in the treatment group and 82 (82%) in the control group completed the study as per the protocol and were included in the per-protocol set (PPS). The intent-to-treat (ITT) analysis included all participants randomized to the study groups and used inverse probability weighting to account for loss to follow-up.

MAIN RESULTS AND THE ROLE OF CHANCE

The ITT analysis showed revealed significantly greater endometrial thickness in the treatment group (mean 8.1 ± 2.5 mm) compared to the control group (mean 6.9 ± 2.1 mm) 21-23 days postabortion (mean difference 1.2 mm, 95% CI 0.7 to 1.9; P < 0.001). The median time to menstrual return was shorter in the treatment group (34 days, inter-quartile range [IQR] 30-38) than in the control group (35 days, IQR 32-42), with a difference of -1 day (95% CI -2.3 to -0.9; P = 0.036). No differences were observed in the timing or volume of bleeding in the first post-abortion cycle. The PPS analysis mirrored the ITT findings. Adverse events were minimal (6% versus 8%), and the blood profile, liver, kidney and coagulation test results were comparable between groups (all P > 0.05).

LIMITATIONS, REASONS FOR CAUTION

Loss to follow-up was 11% in the treatment group and 15% of controls, with no significant difference (P > 0.05). Inconsistencies in the timing of the ultrasonographic scans may have affected the accuracy of endometrial thickness measurements.

WIDER IMPLICATIONS OF THE FINDINGS

Our findings suggest that topical oestrogen supplementation immediately after abortion within the first 10 weeks of gestation improves endometrial regeneration and growth, thereby potentially increasing the chances of a successful subsequent pregnancy. Clinical application of these findings may improve endometrial health management practices and provide a perspective on fertility treatment and women's reproductive health.

STUDY FUNDING/COMPETING INTEREST(S)

This study was supported by a grant (FW-HKKT2021111501900) from Jianmin Pharmaceutical Group Co., Ltd (JMPG), Wuhan, Hubei, China. Both the oestradiol gel and the simulant were provided by JMPG. The funding source had no role in the study. X.Y.L. reports JMPG grant funding paid to their institutions. All other authors declare no competing interests.

TRIAL REGISTRATION NUMBER

CHiCTR2100053565.

TRIAL REGISTRATION DATE

24 November 2021.

DATE OF FIRST PATIENT’S ENROLMENT

9 March 2022.

Effects of platelet-rich fibrin on human endometrial stromal cells behavior in comparison to platelet-rich plasma

Introduction

Intrauterine transfusion of platelet-rich plasma (PRP) has become a new treatment for thin endometrium (TE) in recent years, but its low efficacy due to rapid release of growth factors limits its clinical use. Platelet-rich fibrin (PRF) starts the coagulation cascade reaction immediately after the blood comes into contact with the test tube. The natural coagulation process results in stable platelet activation and the slow release of growth factors.

Methods

In our study, primary human endometrial stromal cells (hESCs) were extracted from endometrial tissue. PRP and PRF were prepared from the patient cubital vein blood. Stromal cells were cultured in conditioned medium supplemented with PRP and PRF. Differences in cell behavior were observed by cell proliferation test and cell migration test. The relative expression levels of apoptotic Bax and antiapoptotic Bcl-2 genes were measured by qRT-PCR. The release of growth factors from PRP and PRF was detected by ELISA.

Results

We found that both PRP and PRF inhibited apoptosis of hESCs, which favored cell proliferation and migration. In addition, PRF releases growth factors for a longer period of time compared to PRP.

Discussion

PRF offer a more sustained therapeutic effect compared to PRP, which provides a new idea for endometrial regeneration and repair.

Advances in Nanomedicine and Biomaterials for Endometrial Regeneration: A Comprehensive Review

The endometrium is an extremely important component of the uterus and is crucial for individual health and human reproduction. However, traditional methods still struggle to ideally repair the structure and function of damaged endometrium and restore fertility. Therefore, seeking and developing innovative technologies and materials has the potential to repair and regenerate damaged or diseased endometrium. The emergence and functionalization of various nanomedicine and biomaterials, as well as the proposal and development of regenerative medicine and tissue engineering techniques, have brought great hope for solving these problems. In this review, we will summarize various nanomedicine, biomaterials, and innovative technologies that contribute to endometrial regeneration, including nanoscale exosomes, nanomaterials, stem cell-based materials, naturally sourced biomaterials, chemically synthesized biomaterials, approaches and methods for functionalizing biomaterials, as well as the application of revolutionary new technologies such as organoids, organ-on-chips, artificial intelligence, etc. The diverse design and modification of new biomaterials endow them with new functionalities, such as microstructure or nanostructure, mechanical properties, biological functions, and cellular microenvironment regulation. It will provide new options for the regeneration of endometrium, bring new hope for the reconstruction and recovery of patients' reproductive abilities.

Efficacy and prognostic factors of combined administration of progesterone and estriol valerate tablets for preventing intrauterine adhesions in patients with early missed abortion following dilation and curettage

OBJECTIVE

To investigate the therapeutic efficacy and prognostic factors of combined administration of estriol valerate tablets and progesterone for the prevention of intrauterine adhesions (IUA) in patients with early missed abortion (EMA) after dilation and curettage.

METHODS

Clinical data of 120 EMA patients undergoing dilation and curettage at Ganzhou People's Hospital from July 2021 to June 2023 were collected for this retrospective study. The 120 enrolled patients were divided into two groups, with 70 patients in the study group receiving both estriol valerate tablets and progesterone for the prevention of IUA, and 50 in the control group undergoing no such treatments at all. The therapeutic efficacy of IUA prevention in patients was compared between the two groups. Subsequently, patients who developed IUA were categorized into the adhesion group (n = 23) and those who did not into the non-adhesion group (n = 97). The clinical data of patients were compared between the adhesion group and the non-adhesion group. Both univariate and multivariate logistic regression analyses were performed to identify the risk factors of IUA in patients with EMA after dilation and curettage. Receiver Operating Characteristic (ROC) curves were drawn to analyze the predictive value of independent risk factors for IUA in patients with EMA after dilation and curettage.

RESULTS

The study group showed a notably higher excellent and good response rate than the control group in IUA prevention (92.00% vs. 82.00%, P = 0.035). Logistic regression analysis revealed that a history of multiple previous miscarriages (P: 0.018; OR: 0.120; 95% CI: 0.02-2.119), relatively small endometrial volume (P: 0.001; OR: 0.026; 95% CI: 0.003-0.210), relatively thin endometrial thickness (P: 0.001; OR: 32.123; 95% CI: 4.339-237.807) and lack of preventive treatment (P: 0.051; OR: 0.211; 95% CI: 0.048-0.935) were independent risk factors for the occurrence of IUA in patients with EMA after dilation and curettage. ROC curve-based analysis showed that these risk factors; encompassing, the number of previous miscarriages, endometrial volume, endometrial thickness and preventive treatment, had a notably higher efficacy in jointly predicting the occurrence of IUA in EMA patients following dilation and curettage in comparison to an individual risk factor alone.

CONCLUSION

The occurrence of IUA in patients with EMA following dilation and curettage is influenced by several factors, including the number of previous miscarriages, the volume and thickness of the endometrium, and preventive treatments. To minimize the risk of IUA, it is crucial to implement proactive interventions prior to uterine surgeries. It was found that a combination therapy involving estriol valerate tablets and progesterone could effectively prevent the development of IUA in patients with EMA after dilation and curettage.

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.

Effect of estradiol after bacterial infection on the Wnt/β-catenin pathway in bovine endometrium epithelial cells and organoids

Endometritis is a disease caused by a postpartum bacterial infection with a poor prognosis that primarily affects dairy cows. Three-dimensional organoids have been used as a model for endometritis, because they exhibit a structure comparable to that of the endometrium, demonstrating both expansibility and hormone responsiveness. These characteristics render them an ideal platform for in vitro investigations of endometrial diseases. Estradiol (E2) is an endogenous steroid hormone with demonstrated anti-inflammatory properties, and the objective of this study was to determine the mechanism by which E2 modulates the inflammatory response and the Wnt signal transduction pathway in bovine endometrial epithelial cells and organoids following E. coli infection. We present the techniques for isolating and culturing primary bovine endometrial epithelial cells (BEECs), and producing endometrial organoids. For the experiments, the endometrial epithelial cells and organoids were infected with E. coli for 1 h, followed by incubation with E2 for 12 h. The mRNA and protein expressions of the inflammation-related genes, IL-1β, IL-6, TLR4, and NF-κB, as well as the Wnt pathway-related genes, Wnt4, β-catenin, c-Myc, and CyclinD1, were assessed using real-time quantitative-PCR and western blotting, respectively. The CCK8 viable cell counting assay was utilized to determine the optimal concentration of the Wnt inhibitor, IWR-1. The mRNA and protein expression of Wnt pathway-related genes was assessed following IWR-1 treatment, while the expression levels of proliferation-associated genes (Ki67, PCNA) and barrier repair genes (occludin, claudin, and Zo-1) in BEECs and organoids were evaluated after E2 treatment. The results of this study show that mRNA expression of the inflammatory genes, IL-1β, TLR4, and NF-κB (P < 0.05) decreased in BEECs following E2 treatment compared to the E. coli group. The protein expression of the IL-1β, IL-6, TLR4 and NF-κB genes was also inhibited (P < 0.05). Similar results were observed in tests on the organoids. Our findings demonstrate that E2 significantly upregulates the expression of Wnt-related genes, including β-catenin and c-Myc, while concurrently downregulating the expression of GSK3β (P < 0.05). Next, we treated E. coli-infected BEECs and organoids with the Wnt inhibitor, IWR-1. Compared with E. coli and E. coli + E2, the expression of mRNA and protein from Wnt 4, β-catenin, and CyclinD1 in E. coli + E2 and E. coli + IWR-1 was down-regulated (P < 0.05). The expression of the proliferation genes, Ki67, PCNA, and the tight junction genes, occludin, claudin1, and Zo-1, in organoids was significantly higher than that in BEECs (P < 0.05). In summary, we found strong potential for E2 mitigation of the E. coli-induced inflammatory response in BEECs and organoids, through activation of the Wnt pathway. In addition, the proliferation and repair capacity of organoids was much higher than that of BEECs.

Multiomics insights into the female reproductive aging

The human female reproductive lifespan significantly diminishes with age, leading to decreased fertility, reduced fertility quality and endocrine function disorders. While many aspects of aging in general have been extensively documented, the precise mechanisms governing programmed aging in the female reproductive system remain elusive. Recent advancements in omics technologies and computational capabilities have facilitated the emergence of multiomics deep phenotyping. Through the application and refinement of various high-throughput omics methods, a substantial volume of omics data has been generated, deepening our comprehension of the pathogenesis and molecular underpinnings of reproductive aging. This review highlights current and emerging multiomics approaches for investigating female reproductive aging, encompassing genomics, epigenomics, transcriptomics, proteomics, metabolomics, and microbiomics. We elucidate their influence on fundamental cell biology and translational research in the context of reproductive aging, address the limitations and current challenges associated with multiomics studies, and offer a glimpse into future prospects.