Endometrial stem cell-derived granulocyte-colony stimulating factor attenuates endometrial fibrosis via sonic hedgehog transcriptional activator Gli2

Detection and quantification of microplastics in endometrial polyps and their role in polyp formation

With the increasing use of plastics, microplastic (MPs) pollution has garnered significant attention in recent years. Endometrial polyps are prevalent gynecological conditions in women of childbearing age, which impair endometrial receptivity and contribute to female infertility. However, no studies have yet reported the exposure of endometrial polyps to MPs. This study employed pyrolysis-gas chromatography/mass spectrometry and laser direct infrared spectroscopy to detect and compare MPs between normal endometrium and endometrial polyps. Using Py-GC/MS, we identified three main MPs in 14 normal endometrial samples and 16 endometrial polyps. The average abundance of MPs in the endometrial polyp group was significantly higher than in the normal endometrium group. The respective average abundance of polyethylene (PE), polystyrene (PS), and polyvinyl chloride (PVC) in the polyp and normal endometrium groups was 13.66 ± 2.0 vs. 7.132 ± 0.78 μg/g (p = 0.0009), 94.81 ± 10.67 vs. 69.29 ± 6.93 μg/g, and 67.67 ± 11.02 vs. 56.35 ± 6.90 μg/g. LDIR analysis revealed 13 different types of MPs, with polymethylmethacrylate being the most prevalent. Moreover, we discovered that PS microspheres can promote the proliferation and migration of endometrial stromal cells through PI3K/AKT pathway, which may be a key factor in the formation of endometrial polyps. This study is the first to explore the presence of MPs in endometrial polyps, compare the differences in MPs content between normal endometrium and endometrial polyps, and clarify the potential connection between MPs exposure and the formation of endometrial polyps. Further research is required to explore additional potential insights.

Prevention of Intrauterine Adhesion with Platelet-Rich Plasma Double-Network Hydrogel

Intrauterine adhesion (IUA) can negatively impact on pregnancy outcomes, leading to reduced pregnancy rates, secondary infertility, and an increased risk of pregnancy complications. Studies have shown that the application of platelet-rich plasma (PRP) in IUA patients is effective. However, the clinical readhesive rate of IUA after treatment is still high, especially in severe cases. Platelet-rich plasma double-network hydrogel (DN gel) is an engineered PRP double network hydrogel, which is a sodium alginate (SA) based PRP hydrogel with egg carton ion cross-linking and fibrin double network. The results of this study show that intrauterine injection of DN gel has a better effect on promoting endometrial regeneration and enhancing endometrial receptivity than PRP gel. The mechanism is analyzed through single-cell sequencing, which may be achieved by increasing the expression of neutrophils (Neut), natural killer cells (NK), and type I classical dendritic cells (cDC1) in the endometrium and inhibiting the infiltration of M2 macrophages. Overall, based on the good healing efficiency and good biocompatibility of DN gel, it is expected to become a method of treating IUA with better efficacy and faster clinical translation.

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

BACKGROUND

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

OBJECTIVE AND RATIONALE

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

SEARCH METHODS

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

OUTCOMES

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

WIDER IMPLICATIONS

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

REGISTRATION NUMBER

https://osf.io/th8yf/.

Intrauterine interventions options for preventing recurrence after hysteroscopic adhesiolysis: a systematic review and network meta-analysis of randomized controlled trials

PURPOSE

Recurrence of adhesions after hysteroscopic adhesiolysis is a challenging clinical problem without a unified management approach. Therefore, we conducted a network meta-analysis that considered both direct and indirect comparisons between interventions to identify optimal strategies for preventing recurrence.

METHODS

We searched for research trials published up to July 2023 from PubMed, Embase and the Cochrane Database. We selected randomized controlled trials comparing the use of different interventions for the prevention of adhesion recurrence, with no language or regional restrictions. We used random-effects models to assess odds ratios (OR) and mean difference (MD) with 95% confidence intervals (CI). Adverse events associated with the interventions were also assessed. This study was registered on PROSPERO, CRD42023449068.

RESULTS

Data from 21 randomized controlled trials involving 2406 patients were synthesized, including interventions with balloon, amnion, platelet-rich plasma (PRP), intrauterine device (IUD), hyaluronic acid (HA), platelet-rich fibrin (PRF), and granulocyte colony-stimulating factor (G-CSF). The top 5 interventions for change in AFS scores were: PRP + Balloon (MD = 5.44; 95% CI, 2.63-8.25), Amnion + Balloon (MD = 5.08; 95% CI, 2.71-7.44), IUD + Balloon (MD = 4.89; 95% CI, 2.49-7.30), HA + Balloon (MD = 3.80; 95% CI, 1.78-5.82), and G-CSF + Balloon (MD = 3.84; 95% CI, 1.05-6.63). There were no statistically significant differences between interventions in the recurrence rate of moderate-to-severe uterine adhesions and the clinical pregnancy rate. Most interventions were safe.

CONCLUSIONS

To our knowledge, this is the most comprehensive network meta-analysis to date of interventions for preventing postoperative intrauterine adhesion recurrence. Our results indicate that PRP + Balloon seems to be the most effective approach.

Novel therapeutic targets, including IGFBP3, of umbilical cord mesenchymal stem-cell-conditioned medium in intrauterine adhesion

Mesenchymal stem cells play important roles in repairing injured endometrium. However, the molecular targets and potential mechanism of the endometrial recipient cells for stem cell therapy in intrauterine adhesion (IUA) are poorly understood. In this study, umbilical cord mesenchymal stem-cell-conditioned medium (UCMSCs-CM) produced positive effects on a Transforming growth factor beta (TGF-β) induced IUA cell model. RNA-sequencing was performed on clinical IUA tissues, and the top 40 upregulated and top 20 downregulated mRNAs were selected and verified using high-throughput (HT) qPCR in both tissues and cell models. Based on a bioinformatic analysis of RNA-sequencing and HT-qPCR results, 11 mRNAs were uncovered to be the intervention targets of UCMSCs-CM on IUA endometrium cell models. Among them, IGFBP3 was striking as a key pathogenic gene and a potential diagnostic marker of IUA, which exhibited the area under the curve (AUC), sensitivity, specificity were 0.924, 93.1% and 80.6%, respectively in 60 endometrial tissues. The silencing of IGFBP3 exerted positive effects on the IUA cell model through partially upregulating MMP1 and KLF2. In conclusion, RNA-sequencing combined with HT qPCR based on clinical tissues and IUA cell models were used in IUA research and our results may provide some scientific ideas for the diagnosis and treatment of IUA.

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

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

Review on Additives in Hydrogels for 3D Bioprinting of Regenerative Medicine: From Mechanism to Methodology

The regeneration of biological tissues in medicine is challenging, and 3D bioprinting offers an innovative way to create functional multicellular tissues. One common way in bioprinting is bioink, which is one type of the cell-loaded hydrogel. For clinical application, however, the bioprinting still suffers from satisfactory performance, e.g., in vascularization, effective antibacterial, immunomodulation, and regulation of collagen deposition. Many studies incorporated different bioactive materials into the 3D-printed scaffolds to optimize the bioprinting. Here, we reviewed a variety of additives added to the 3D bioprinting hydrogel. The underlying mechanisms and methodology for biological regeneration are important and will provide a useful basis for future research.

SHH/GLI2-TGF-β1 feedback loop between cancer cells and tumor-associated macrophages maintains epithelial-mesenchymal transition and endoplasmic reticulum homeostasis in cholangiocarcinoma

BACKGROUND

Tumor-associated macrophages (TAMs) play a dual role in tumors. However, the factors which drive the function of TAMs in cholangiocarcinoma remain largely undefined.

METHODS

SHH signaling pathway and endoplasmic reticulum stress (ERS) indicators were detected in clinical tissues and cholangiocarcinoma cell lines. TAMs were co-cultured with cholangiocarcinoma cells under conditions of hypoxia/normoxia. Polarized TAMs were counted by flow cytometry, and TGF-β1 levels in cell supernatants were detected by ELISA. The effects of glioma-associated oncogene GLI2 on TAMs themselves and cholangiocarcinoma cells were examined by conducting interference and overexpression assays.

RESULTS

The SHH signaling pathway and ERS were both activated in tumor tissues or tumor cell lines under conditions of hypoxia. In co-culture experiments, the presence of cholangiocarcinoma cells increased the proportion of M2-polarized TAMs and the secretion of TGF-β1 by TAMs, while knockdown of SHH expression reversed those increases. Overexpression of GLI2 in TAMS or stimulation of TAMS with Hh-Ag1.5 increased their levels of TGF-β1 expression. Furthermore, under co-culture conditions, interference with GLI2 expression in TAMs reduced the tumor cell migration, invasion, and ER homeostasis induced by Hh-Ag1.5-pretreated TAMs. Under conditions of hypoxia, the presence of cholangiocarcinoma cells promoted the expression of GLI2 and TGF-β1 in Tams, and in turn, TAMs inhibited the apoptosis and promoted the migration and invasion of cholangiocarcinoma cells. In vivo, an injection of cholangiocarcinoma cells plus TAMs contributed to the growth, EMT, and ER homeostasis of tumor tissue, while an injection of TAMs with GLI2 knockdown had the opposite effects.

CONCLUSION

Cholangiocarcinoma cells regulated TAM polarization and TGF-β1 secretion via a paracrine SHH signaling pathway, and in turn, TAMs promoted the growth, EMT, and ER homeostasis of cholangiocarcinoma cells via TGF-β1.

Animal models in intrauterine adhesion research

Intrauterine adhesion (IUA) is a gynaecological disease caused by uterine cavity surgeries and infections that leads to partial or total occlusion of the uterine cavity. However, the underlying mechanism(s) and progression of the disease have not yet been identified. IUA has a high recurrence rate and poor prognosis, and effective drugs to prevent adhesion are lacking. Therefore, establishing an effective animal model of IUA is of great significance for revealing the pathogenesis of IUA and the mechanism(s) governing drug effects. Rats, mice, rabbits, and other animals are currently used to establish intrauterine adhesion models. The IUA induction methods include chemical, thermal, or mechanical damage and mechanical damage combined with an infective method. We analysed the advantages and disadvantages of various models and their clinical simulations in order to provide a precise animal model for exploring the pathogenesis, treatment strategies, and prevention of IUA.

Human umbilical cord blood-derived MSCs trans-differentiate into endometrial cells and regulate Th17/Treg balance through NF-κB signaling in rabbit intrauterine adhesions endometrium

Purpose

The fundamental cause of intrauterine adhesions (IUAs) is the destruction and reduction in stem cells in endometrial basal layer, resulting in endometrial reconstruction very difficult. The purpose of this study was to investigate the effects and underlying mechanism of human umbilical cord blood-derived mesenchymal stem cells (hUCB-MSCs) on the endometrial reconstruction after transplantation.

Methods

hUCB-MSCs were isolated and identified by flow cytometry, osteogenic, adipogenic and chondrogenic differentiation assays. The rabbit IUA models were established and set five groups (control, 14/28th day after surgery, estrogen and hUCB-MSCs treatment). The number of endometrial glands and the fibrosis rate were evaluated using HE and Masson staining, respectively. Endometrial proliferation, angiogenesis and inflammation were evaluated by immunohistochemical staining of ER, Ki-67and TGF-β1, respectively. Single-cell RNA sequencing (scRNA-seq) was applied to explore the cell differentiation trajectory after hUCB-MSCs transplanted into IUA endometrium. Finally, molecular mechanism of hUCB-MSCs repairing damaged endometrium was investigated by RNA sequencing, qRT-PCR and Western blot assays.

Results

After transplantation of the hUCB-MSCs, the increase in endometrial gland number, estrogen receptor (ER) and Ki-67 expression, and the decrease in fibrosis rate and TGF-β expression (P < 0.05), suggested the endometrial repair, angiogenesis and inflammatory suppression. The therapeutic effect of hUCB-MSCs was significantly improved compared with 28th day after surgery and estrogen group. ScRNA-seq demonstrated that the transplanted hUCB-MSCs can trans-differentiate into endometrial cells: epithelial, fibroblast and macrophage. RNA sequencing of six IUA samples combined with qRT-PCR and Western blot assays further revealed that hUCB-MSCs may regulate Th17/Treg balance through NF-κB signaling, thus inhibiting the immune response of damaged endometrium.

Conclusions

Our study demonstrated that hUCB-MSCs can repair damaged endometrium through trans-differentiation, immunomodulatory capacities and NF-κB signaling, suggesting the treatment value of hUCB-MSCs in IUA.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13287-022-02990-1.

Granulocyte colony-stimulating factor in reproductive-related disease: Function, regulation and therapeutic effect

Granulocyte colony-stimulating factor (G-CSF) is one of the cytokines which plays important roles in embryo implantation and normal pregnancy. At the maternal-fetal interface, G-CSF can be synthesized by multiple cells, and participates in regulation of trophoblast development, endometrial decidualization, placental metabolism and angiogenesis. Moreover, as an important medium of intercellular communication, G-CSF has also been shown to exert key roles in crosstalk between cellular components at the maternal-fetal interface. Recently, our study demonstrated that G-CSF derived from M2 macrophage could promote trophoblasts invasion and migration through activating PI3K/AKT/Erk1/2 pathway, thereby involving in normal pregnancy program. Herein, we will summarize the role and regulation of G-CSF in normal pregnancy and reproductive-related disease, and the clinical applications of G-CSF in patients undergoing in vitro fertilization with thin endometrium, repeated implantation failure, and women suffered with recurrent spontaneous abortion.

Exosomes Derived From CTF1-Modified Bone Marrow Stem Cells Promote Endometrial Regeneration and Restore Fertility

Background: Thin endometrial tissue is a leading cause of embryo transfer failure, potentially contributing to sustained infertility and associated adverse outcomes. The application of exosomes derived from autologous or allogeneic bone marrow-derived stem cells (BMSCs) has been used to promote uterine repair following injury, and there is also prior evidence that stem cell transplantation can bolster fertility. Genetic modifications represent a primary approach to enhancing exosomal therapy strategies. The present study thus explored the effects of Cardiotrophin-1 (CTF1)-modified BMSCs-exo on fertility-related outcomes.

Methods: An adenoviral vector was used to generate CTF1-overexpressing BMSCs (C-BMSCs), after which exosomes were isolated from control BMSCs (BMSC-exos) and C-BMSCs (C-BMSC-exos). The angiogenic effects of C-BMSC-exo treatment were assessed through analyses of endothelial cell proliferation and tube formation. Model rats exhibiting endometrial thinning were administered C-BMSCs-exo, after which the effects of such treatment were assessed through H&E staining, Masson’s trichrome staining, and immunofluorescence analyses. The mechanistic basis for the proangiogenic effects of CTF1 as a driver of endometrial regeneration was additionally explored.

Results: C-BMSC-exo treatment of HUVECs was associated with enhanced neovascularization, as evidenced by improved in vitro proliferation, migration, and tube formation. Importantly, such treatment was also linked to tissue regeneration, neovascularization, and the suppression of localized tissue fibrosis in vivo. Regenerated endometrial tissue exhibited higher embryo receptivity and was associated with higher birth rates in treated rats. The upregulation of the JAK/PI3K/mTOR/STAT3 signaling pathways in C-BMSC-exo-treated rats may underscore the mechanistic basis whereby CTF1 can positively impact endometrial angiogenesis and regeneration.

Conclusion: Our data suggest that exosomes produced by CTF1-modified BMSCs can more effectively promote the regeneration of endometrial and myometrial tissues, driving neovascularization in a manner that improves endometrial receptivity in a rat model system, highlighting the therapeutic promise of this approach for patients diagnosed with endometrial thinning.

miR-223-3p alleviates TGF-β-induced epithelial-mesenchymal transition and extracellular matrix deposition by targeting SP3 in endometrial epithelial cells

Intrauterine adhesion (IUA) is the clinical manifestation of endometrial fibrosis. The dysregulation of microRNAs (miRNAs) has been confirmed to implicate in a diversity of human diseases, including IUA. Nevertheless, the specific function of miR-223-3p in IUA remains to be clarified. Reverse transcription quantitative polymerase chain reaction analysis displayed the downregulation of miR-223-3p in IUA tissues and endometrial epithelial cells (EECs). Results from wound healing assay, Transwell assay and western blotting showed that TGF-β facilitated the migration and invasion of EECs and induced epithelial-mesenchymal transition (EMT) process as well as extracellular matrix (ECM) deposition. Overexpression of miR-223-3p in EECs was shown to suppress the effects induced by TGF-β. Bioinformatics analysis and luciferase reporter assay revealed the binding relation between miR-223-3p and SP3. SP3 was highly expressed in IUA and its expression was inversely correlated with miR-223-3p expression in IUA tissue samples. Additionally, upregulation of SP3 reversed the influence of miR-223-3p on the phenotypes of EECs. In conclusion, miR-223-3p alleviates TGF-β-induced cell migration, invasion, EMT process and ECM deposition in EECs by targeting SP3.

Endometrium Derived Stem Cells as Potential Candidates in Nervous System Repair

Limited cell division and lack of endogenous repair mechanisms in the central nervous system, hampers tissue repair following neurodegenerative diseases or tissue injuries. Unlike central nervous system; peripheral nervous system has some capacity to repair after injury, but in case of critical sized defects the use of supporting cells in the neural guidance channels seems inevitable to obtain a satisfactory functional recovery. Stem cell therapies have provided new frontiers in the repair of nervous system largely through paracrine secretion mechanisms. The therapeutic potential of stem cells differs according to their tissue of origin, mode of isolation, administration route, and passage number. During the past decades, studies have been focused on stem cells harvested from disposable tissues such as menstrual blood or biopsies from endometrium. These cells are characterized by their high differentiation and proliferation potential, ease of harvest, and lack of ethical concerns. In the current review, we will discuss the prospects and challenges of endometrial stem cells' application in nervous system repair.

3D-printed hydrogel scaffold-loaded granulocyte colony-stimulating factor sustained-release microspheres and their effect on endometrial regeneration

After injury, the endometrium cannot self-repair or regenerate because damages of the basal layer of the uterine, which often lead to intrauterine adhesions (IUAs), which can cause serious problems such...

The Top 100 Most Cited Articles on Intrauterine Adhesion: a Bibliometric Analysis

Bibliometric analysis is a statistical method that attempts to assess articles by their citations, analyzing their frequency and citation pattern, which subsequently gleans direction and guidance for future research. Over the past few years, articles focused on intrauterine adhesions have been published with increasing frequency. Nevertheless, little is known about the properties and qualities of this research, and no current analysis exists that has examined the progress in intrauterine adhesion research. Web of Science Core Collection, BIOSIS Citation Index, and MEDLINE database were searched to identify articles on intrauterine adhesion published from 1950 to October 2020. The 100 most cited articles were chosen to analyze citation count, citation density, authorship, theme, geographic distribution, time-related flux, level of evidence, and network analysis. An overwhelming majority of these 100 articles were published in the 2010s (35%). Citations per article ranged from 30 to 253. Chinese authors published the most papers in the top 100, followed by the USA, France, Israel, and Italy. The most salient study themes included operative hysteroscopy and adjunctive treatments for improving reproductive outcomes. The most common level of evidence was level II, and there was no statistical difference in the number of citations between the levels. The network analysis indicated that hysteroscopy, hysteroscopic adhesiolysis, infertility, and the reproductive outcome had a great degree of centrality in the 2000s and 2010s. In comparison, placental implantation had a great degree of centrality in the 2000s, and stem cell and fibrosis had a great degree of centrality in the 2010s. The value of IUA investigation has been gradually appreciated recently. Hysteroscopic adhesiolysis was continuously explored to achieve better reproductive outcome. Over time, the main focus of research has gradually shifted from complications to postoperative adjuvant treatment. Moreover, breakthrough progress is needed in underlying mechanism and early prevention of IUA.

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.

Development of Anti-fibrotic Therapy in Stricturing Crohn's Disease: Lessons from Randomized Trials in Other Fibrotic Diseases

Intestinal fibrosis is considered an inevitable complication of Crohn's disease (CD) that results in symptoms of obstruction and stricture formation. Endoscopic or surgical treatment is required to treat the majority of patients. Progress in the management of stricturing CD is hampered by the lack of effective anti-fibrotic therapy; however, this situation is likely to change because of recent advances in other fibrotic diseases of the lung, liver and skin. In this review, we summarized data from randomized controlled trials (RCT) of anti-fibrotic therapies in these conditions. Multiple compounds have been tested for the anti-fibrotic effects in other organs. According to their mechanisms, they were categorized into growth factor modulators, inflammation modulators, 5-hydroxy-3-methylgultaryl-coenzyme A (HMG-CoA) reductase inhibitors, intracellular enzymes and kinases, renin-angiotensin system (RAS) modulators and others. From our review of the results from the clinical trials and discussion of their implications in the gastrointestinal tract, we have identified several molecular candidates that could serve as potential therapies for intestinal fibrosis in CD.

Unresponsive thin endometrium caused by Asherman syndrome treated with umbilical cord mesenchymal stem cells on collagen scaffolds: a pilot study

Background

Unresponsive thin endometrium caused by Asherman syndrome (AS) is the major cause of uterine infertility. However, current therapies are ineffective. This study is to evaluate the effect of transplantation with collagen scaffold/umbilical cord mesenchymal stem cells (CS/UC-MSCs) on this refractory disease.

Methods

Eighteen infertile women with unresponsive thin endometrium, whose frozen–thawed embryo transfers (FETs) were cancelled due to reduced endometrial thickness (ET ≤ 5.5 mm), were enrolled in this before and after self-control prospective study. Hysteroscopic examination was performed to confirm no intrauterine adhesions, then twenty million UC-MSCs loaded onto a CS were transplanted into the uterine cavity in two consecutive menstrual cycles. Then uterine cavity was assessed through hysteroscopy after two transplants. FETs were performed in the following cycle. Pregnancy outcomes were followed up. Endometrial thickness, uterine receptivity and endometrial angiogenesis, proliferation and hormone response were compared before and after treatment.

Results

Sixteen patients completed the study. No treatment-related serious adverse events occurred. Three months after transplantation, the average ET increased from 4.08 ± 0.26 mm to 5.87 ± 0.77 mm (P < 0.001). Three of 15 patients after FET got pregnant, of whom 2 gave birth successfully and 1 had a miscarriage at 25 weeks’ gestation. One of 2 patients without FET had a natural pregnancy and gave birth normally after transplantation. Immunohistochemical analysis showed increased micro-vessel density, upregulated expression of Ki67, estrogen receptor alpha, and progesterone receptor, indicating an improvement in endometrial angiogenesis, proliferation, and response to hormones.

Conclusion

CS/UC-MSCs is a promising and potential approach for treating women with unresponsive thin endometrium caused by AS.

Trial registration

ClinicalTrials.gov NCT03724617. Registered on 26 October 2018—prospectively registered, https://register.clinicaltrials.gov/

Supplementary Information

The online version contains supplementary material available at 10.1186/s13287-021-02499-z.

The Sonic Hedgehog signaling pathway regulates autophagy and migration in ovarian cancer

Background

The Sonic Hedgehog (SHH) signaling pathway plays an important role in various types of human cancers including ovarian cancer; however, its function and underlying mechanism in ovarian cancer are still not entirely understood.

Methods

We detected the expressions of SHH and SQSTM1 in borderline ovarian tumor tissues, epithelial ovarian cancer (EOC) tissues and benign ovarian tumor tissues. Cyclopamine (Cyp, a well‐known inhibitor of SHH signaling pathway) and chloroquine (CQ, the pharmaceutical inhibitor of autophagy) were used in vivo and in vitro (autophagic flux, CCK‐8 assay, wound healing assay, transwell assay, tumor xenograft model). The mechanism of action was explored through Quantitative RT‐PCR and Western Blot.

Results

We found up‐regulation of SHH and accumulation of SQSTM1/P62 in epithelial ovarian cancer. Cyp induced autophagy through the PI3K/AKT signaling pathway. Moreover, low‐dose Cyp and chloroquine (CQ) significantly promoted the migratory ability of SKOV3 cells.

Conclusions

Our findings suggest that inhibition of the SHH pathway and autophagy may be a potential and effective therapy for the treatment of ovarian cancer.

Variations in the Profiles of Vascular-Related Factors Among Different Sub-Types of Polycystic Ovarian Syndrome in Northern China

Recently, a growing body of evidence has suggested that abnormal ovarian angiogenesis, secondary to the imbalance between various angiogenic markers, is involved in the pathogenesis of PCOS, and this has led to the use of various interventions (such as Diane-35) to restore the normal ovarian angiogenesis. Therefore, we conducted the current investigation to determine the role of such markers (endothelial growth factor (VEGF), endostatin (ES), and thrombospondin-1 (TSP-1)) in the pathogenesis of PCOS along with the associated changes in ovarian blood flow in patients with PCOS compared to healthy controls, both before and after a course of oral contraception. A total of 381 patients with PCOS and 98 healthy females of childbearing age were recruited from July 2014 to June 2017 at the Reproductive Center of the Second Affiliated Hospital of Harbin Medical University. The serum levels of VEGF, ES, and TSP-1 were determined by enzyme-linked immunosorbent assay, while ovarian perfusion was measured by the pulsatility index (PI) and resistance index (RI) by using transvaginal color Doppler ultrasound. Repeated analyses were carried out after 3 months of Diane-35 treatment. Post-treatment serum levels of luteinizing hormone (LH)/follicle stimulating hormone (FSH) ratio of patients with PCOS decreased significantly (P <0.05). The RI values of most PCOS patients increased after treatment (P<0.05), while PI was significantly increased in all patients (P<0.05). However, variable changes in the serum levels of TSP-1, VEGF, and ES after treatment were observed. Serum VEGF levels showed a negative correlation with serum LH/FSH ratio, T concentration, and ES (P <0.05), while ES levels were negatively correlated with serum T concentrations only (P<0.05). The markers of angiogenesis (VEGF, ES, and TSP-1) were expressed differently among PCOS patients, who also responded differently to the same course of Diane-35 treatment. This field still warrants further investigation to reach a more definitive conclusion.

Quercetin regulates fibrogenic responses of endometrial stromal cell by upregulating miR-145 and inhibiting the TGF-β1/Smad2/Smad3 pathway

OBJECTIVES

Aim of this study is to explore whether quercetin can inhibit the enlarged fibrogenic responses of endometrial stromal cells by increasing the level of microRNA-145 (miR-145) and mediating the TGFβ1/Smad2/Smad3 signaling pathway, and to discuss the mechanism of signal transduction, further to provide experimental basis for revealing the pathophysiological mechanism and seeking new strategies for effective prevention and treatment of endometrial fibrosis.

METHODS

The expression levels of miR-145 and TGF-β receptor 2 (TGFBR2) were detected by RT-qPCR analysis. Expressions of α-smooth muscle actin (α-SMA) and vimentin were examined by immunofluorescence staining. Cell viability was measured by MTT assay. The protein expression of collagen type 1 alpha 1 (Col1a1), α-SMA, fibronectin (FN), TGFBR2, transforming growth factor (TGF-β1), Smad2/3, phospho-Smad2/3 (p-Smad2/3) were detected by western blot analysis. The interaction between miR-145 and TGFBR2 was confirmed by dual-luciferase reporter gene assay.

RESULTS

The expression level of miR-145 was decreased, whereas TGFBR2 was increased in intrauterine adhesion tissue. The expression levels of COL1A1, α-SMA, FN, TGFBR2, and p-Smad2/3 were increased, whereas miR-145 and cell proliferation were decreased in human endometrial stromal cells (hESCs) in response to TGF-β1 stimulation in a time and dose-dependent manner, which could be reversed by quercetin. Furthermore, quercetin regulates cell fibrogenic responses of endometrial stromal cells via miR-145/TGF-β1/Smad2/Smad3 pathway.

CONCLUSIONS

These findings indicated that quercetin have a significant anti-fibrotic effect and could upregulate miR-145 and inhibit activation of TGF-β1/Smad2/Smad3 pathway to regulate TGF-β1 induced fibrogenic responses of endometrial stromal cells, which may serve as a potential therapeutic agent for endometrial fibrosis.

Overactivated sonic hedgehog signaling aggravates intrauterine adhesion via inhibiting autophagy in endometrial stromal cells

Autophagy can be dynamically induced in response to stresses and is an essential, ubiquitous intracellular recycling system that impacts the fate of damaged resident cells, thereby influencing wound healing. Endometrial fibrosis is a form of abnormal wound healing that causes intrauterine adhesion (IUA) and infertility. We previously demonstrated that overactivated sonic hedgehog (SHH) signaling exacerbated endometrial fibrosis, but the role of autophagy in this process is still unknown. Here, we report that impaired autophagy participates in SHH pathway-induced endometrial fibrosis. Endometrial stroma-myofibroblast transition accompanied by autophagy dysfunction was present in both endometrial biopsies of IUA patients and Amhr2^cre/+R26-SmoM2^+/− (AM2) transgenic mouse. Mechanistically, SHH pathway negatively regulated autophagy through pAKT-mTORC1 in a human endometrial stromal cell line (T-HESCs). Furthermore, SHH pathway-mediated fibrosis was partly counteracted by autophagy modulation in both T-HESCs and the murine IUA model. Specifically, the impact of SHH pathway inhibition (GANT61) was reversed by the pharmacological autophagy inhibitor chloroquine (CQ) or RNA interference of autophagy-related gene ATG5 or ATG7. Similar results were obtained from the murine IUA model treated with GANT61 and CQ. Moreover, promoting autophagy with rapamycin reduced fibrosis in the AM2 IUA model to baseline levels. In summary, defective autophagy is involved in SHH pathway-driven endometrial fibrosis, suggesting a potential novel molecular target for IUA treatment.

Silica Perturbs Primary Cilia and Causes Myofibroblast Differentiation during Silicosis by Reduction of the KIF3A-Repressor GLI3 Complex

The purpose of this study was to determine the effects of Kinesin family member 3A (KIF3A) on primary cilia and myofibroblast differentiation during silicosis by regulating Sonic hedgehog (SHH) signalling. Methods: Changes in primary cilia during silicosis and myofibroblast differentiation were detected in silicotic patients, experimental silicotic rats, and a myofibroblast differentiation model induced by SiO₂. We also explored the mechanisms underlying KIF3A regulation of Glioma-associated oncogene homologs (GLIs) involved in myofibroblast differentiation. Results: Primary cilia (marked by ARL13B and Ac-α-Tub) and ciliary-related proteins (IFT 88 and KIF3A) were increased initially and then decreased as silicosis progressed. Loss and shedding of primary cilia were also found during silicosis. Treatment of MRC-5 fibroblasts with silica and then transfection of KIF3A-siRNA blocked activation of SHH signalling, but increased GLI2^FL as a transcriptional activator of SRF, and reduced the inhibitory effect of GLI3^R on ACTA2. Conclusion: Our findings indicate that primary cilia are markedly altered during silicosis and the loss of KIF3A may promote myofibroblast differentiation induced by SiO₂.

Therapeutic options and drug delivery strategies for the prevention of intrauterine adhesions

Intrauterine adhesions (IUAs) are bands of fibrous tissue that form in the endometrial cavity and associated with the increased risk of abnormal menstruation, recurrent pregnancy loss, secondary infertility, and pregnancy complications. Physical barriers, including intrauterine device and hydrogel, were clinical available to prevent the post-operational IUAs. But physically separation of the injured endometrium relies on the own limited healing power and often ends with recurrence. In recent years, the mechanisms driving IUAs treatment has validated the application of hormones, and further stem cell therapy has also led to the development of novel therapeutic agents with promising efficacy in pre-clinical and initial clinical studies. Still, it is challenging to delivery the therpaeutic factors to the injured uterus. Herein, in this review, we discuss the traditional intervention methods for the prevention of IUAs, as well as novel therapeutics and delivery strategies that will most likely change the treatment paradigms for better clinical outcomes. The combination strategy that using physical barriers as the delivery carriers for therapeutics might provide new alternatives for the prevention of IUAs.

A collagen scaffold loaded with human umbilical cord-derived mesenchymal stem cells facilitates endometrial regeneration and restores fertility

In women of reproductive age, severe injuries to the endometrium are often accompanied by endometrial scar formation or intrauterine adhesions (IUAs), which can result in infertility or miscarriage. Although many approaches have been used to treat severe IUAs, high recurrence rates and endometrial thinning have limited therapeutic efficiency. In this study, a collagen scaffold (CS) loaded with human umbilical cord-derived mesenchymal stem cells (UC-MSCs) was fabricated and applied for endometrial regeneration. The CS/UC-MSCs promoted human endometrial stromal cell proliferation and inhibited apoptosis in vitro through paracrine effects. In a model of endometrial damage, transplantation with the CS/UC-MSCs maintained normal luminal structure, promoted endometrial regeneration and collagen remodeling, induced intrinsic endometrial cell proliferation and epithelium recovery, and enhanced the expression of estrogen receptor α and progesterone receptor. An improved ability of the regenerated endometrium to receive embryos was confirmed. Together, our results indicate that the CS/UC-MSCs promoted endometrial structural reconstruction and functional recovery. Topical administration of the CS/UC-MSCs after trans-cervical resection of adhesions might prevent re-adhesion, promote endometrium regeneration and improve pregnancy outcomes for patients with severe IUAs. STATEMENT OF SIGNIFICANCE: Intrauterine adhesions due to severe endometrium injuries happen frequently in clinic and become one of the crucial reasons for women's infertility or miscarriage. Therefore, how to regenerate the damaged endometrium is a big challenge. In this study, a collagen scaffold (CS) loaded with human umbilical cord-derived mesenchymal stem cells (UC-MSCs) was fabricated and applied for endometrium regeneration. Herein, UC-MSCs, known for low immunogenicity and high proliferative potential, exhibit promising potential for endometrium regeneration; and collagen scaffolds provide suitable physical support. It was proved that transplantation with CS/UC-MSCs promoted endometrial regeneration and fertility restoration. It suggested that topical administration of CS/UC-MSCs in uterus could be a promising strategy for patients suffering severe intrauterine adhesion and infertility.

Establishment and comparison of different intrauterine adhesion modelling procedures in rats

Intrauterine adhesion (IUA) is caused by endometrial damage and leads to the formation of scar fibrosis and repair disorders. We compared four different rat IUA modelling procedures in order to establish a stable animal model suitable for investigating IUA. Twenty female Sprague--Dawley rats were randomly divided into four groups. IUA was induced on one side of each rat uterus by ethanol instillation, heat stripping, mechanical injury or mechanical injury with infection (dual-injury); the other side of the uterus was left intact as a control. After 8 days the rats were sacrificed, their uteri were examined for histomorphology and expression of endometrial markers was checked using immunohistochemistry. All four IUA modelling procedures resulted in visual pathophysiological changes in the rat uterus, including stenosis, congestion and loss of elasticity. Endometrial thinning, shrinkage of glands and formation of fibrotic hyperplasia were also observed. All four procedures resulted in the downregulation of cytokeratin 18 and vimentin expression compared with control tissues, as well as the upregulation of collagen I expression. After mechanical injury and dual-injury the expression of interleukin 6 was significantly increased. Overall, our results suggest that ethanol instillation is the most stable IUA modelling procedure. Mechanical injury reliably yielded inflammatory indicators.

Human menstrual blood-derived stem cells promote the repair of impaired endometrial stromal cells by activating the p38 MAPK and AKT signaling pathways

Multiple studies have confirmed that human menstrual blood-derived stem cells (MenSCs) have potential applications in regenerative medicine or cell therapy. However, the contribution of MenSCs to endometrial repair is currently unknown. We evaluated the protective effects of MenSCs on impaired endometrial stromal cells (ESCs), as well as the signaling pathways involved in this process. Mifepristone was used to damage human ESCs, which were subsequently cocultured with MenSCs. The proliferation, apoptosis, and migration of ESCs were assessed, together with the expression of related signaling proteins including total p38 mitogen-activated protein kinase, P-p38, total protein kinase B (AKT), P-AKT, β-catenin, and vascular endothelial growth factor (VEGF). MenSCs significantly recovered the proliferation and migration ability of impaired ESCs, inhibited ESC apoptosis, and upregulated protein expression of P-AKT, P-p38, VEGF, and β-catenin. Our findings suggest that MenSC-based therapies could be promising strategies for the treatment of endometrial injury, and that AKT and p38 signaling pathways may be involved in this process.