Synergistic regenerative therapy of thin endometrium by human placenta-derived mesenchymal stem cells encapsulated within hyaluronic acid hydrogels

Autologous PRP therapy for thin endometrium: A self-controlled case series study across menstrual cycles

OBJECTIVES

Thin endometrium (TE) compromises endometrial receptivity, often leading to implantation failure and lower clinical pregnancy rates. As autologous platelet-rich plasma (PRP) emerges as a potential remedy, the present study focused on its therapeutic effects on TE in infertile women who underwent frozen embryo transfer.

STUDY DESIGN

Patients with TE who underwent frozen embryo transfer treatment in our hospital were included. To diminish individual variability, a self-controlled series approach was used. Two menstrual study cycles were arranged for each participant before the actual embryo transfer cycle; PRP treatment was conducted in the second cycle. Key metrics analyzed included endometrial thickness and the expression of specific endometrial biomarkers including HOXA-10, Ki67, and αvβ3 integrin. Transvaginal ultrasound was employed to measure endometrial thickness on Days 11 and 14, and an endometrial biopsy was conducted on progesterone Day 5 of the first two cycles. Pregnancy outcomes were observed after the embryo transfer cycle.

RESULTS

PRP treatment significantly increased the median endometrial thickness, from 5.8 mm to 6.5 mm (P = 0.0066). Additionally, PRP treatment resulted in a statistically significant increase in the H-score for all endometrial markers. Importantly, during the subsequent embryo transfer cycle with PRP treatment, two patients successfully achieved pregnancies, both culminating in live births.

CONCLUSIONS

These findings emphasize the potential of PRP in improving endometrial conditions, especially for individuals grappling with thin endometrium issues, as underscored by this self-comparison methodology.

Human Amniotic Epithelial Stem Cells Alleviate Autoimmune Premature Ovarian Insufficiency in Mice by Targeting Granulosa Cells via AKT/ERK Pathways

Autoimmune factors play an important role in premature ovarian insufficiency (POI). Human amniotic epithelial stem cells (hAESCs) have recently shown promising treatment effects on chemotherapy-induced POI. However, the therapeutic efficacy and underlying mechanisms of hAESCs in autoimmune POI remain to be investigated. In this study, we showed for the first time that intravenous transplantation of hAESCs could reside in the ovary of zona pellucida 3 peptide (pZP3) induced autoimmune POI mice model for at least 4 weeks. hAESCs could improve ovarian function and fertility, alleviate inflammation and reduce apoptosis of granulosa cells (GCs) in autoimmune POI mice. The transcriptome analysis of mice ovaries and in vitro co-cultivation experiments suggest that activation of the AKT and ERK pathways may be the key mechanism in the therapeutic effect of hAESCs. Our work provides the theoretical and experimental foundation for optimizing the administration of hAESCs, as well as the clinical application of hAESCs in autoimmune POI patients.

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

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

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.

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/.

Validity of stem cell-loaded scaffolds to facilitate endometrial regeneration and restore fertility: a systematic review and meta-analysis

Objective

Various stem cell-loaded scaffolds have demonstrated promising endometrial regeneration and fertility restoration. This study aimed to evaluate the efficacy of stem cell-loaded scaffolds in treating uterine injury in animal models.

Methods

The PubMed, Embase, Scopus, and Web of Science databases were systematically searched. Data were extracted and analyzed using Review Manager version 5.4. Improvements in endometrial thickness, endometrial glands, fibrotic area, and number of gestational sacs/implanted embryos were compared after transplantation in the stem cell-loaded scaffolds and scaffold-only group. The standardized mean difference (SMD) and confidence interval (CI) were calculated using forest plots.

Results

Thirteen studies qualified for meta-analysis. Overall, compared to the scaffold groups, stem cell-loaded scaffolds significantly increased endometrial thickness (SMD = 1.99, 95% CI: 1.54 to 2.44, P < 0.00001; I² = 16%) and the number of endometrial glands (SMD = 1.93, 95% CI: 1.45 to 2.41, P < 0.00001; I² = 0). Moreover, stem cell-loaded scaffolds present a prominent effect on improving fibrosis area (SMD = -2.50, 95% CI: -3.07 to -1.93, P < 0.00001; I² = 36%) and fertility (SMD = 3.34, 95% CI: 1.58 to 5.09, P = 0.0002; I² = 83%). Significant heterogeneity among studies was observed, and further subgroup and sensitivity analyses identified the source of heterogeneity. Moreover, stem cell-loaded scaffolds exhibited lower inflammation levels and higher angiogenesis, and cell proliferation after transplantation.

Conclusion

The evidence indicates that stem cell-loaded scaffolds were more effective in promoting endometrial repair and restoring fertility than the scaffold-only groups. The limitations of the small sample sizes should be considered when interpreting the results. Thus, larger animal studies and clinical trials are needed for further investigation.

Systematic review registration

https://www.crd.york.ac.uk/PROSPERO, identifier CRD42024493132.

Janus adhesive microneedle patch loaded with exosomes for intrauterine adhesion treatment

Intrauterine adhesions (IUAs) are common sequelae of cervical mucosa damage caused by uterine curettage. Establishing an anti-adhesion barrier between the damaged endometrium with a sustained-release drug capability and hence promoting endogenous regeneration of the endometrium is an available treatment for IUA. However, current therapy lacks long-term intracavitary residence, drug-delivery permeability, and tissue anti-adhesion to the endometrium. Here, we report the design of a Janus microneedle patch consisting of two layers: an adhesive inner layer with an exosomes-loaded microneedle, which endows the patch with a tissue adhesive capability as well as transdermal drug-delivery capability; and an anti-adhesion outer layer, which prevents the intrauterine membrane from postoperative adhesion. This Janus adhesive microneedle patch firmly adhered to uterine tissue, and sustainedly released ∼80% of the total loaded exosomes in 7 days, hence promoting the expression of vascular- and endothelial-related cell signals. Furthermore, the anti-adhesive layer of the microneedle patch exhibited low cell and protein adhesion performance. In rats, the microneedle patch successfully prevented uterine adhesions, improved endometrial angiogenesis, proliferation, and hormone response levels. This study provides a stable anti-adhesion barrier as well as efficient drug-release capability treatment for intrauterine adhesion treatment.

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.

Research progress on the STAT signaling pathway in pregnancy and pregnancy-associated disorders

Signal transducer and activator of transcription (STAT) proteins, pivotal regulators of signaling cascades, undergo activation in response to the stimulation of cytokines and growth factors, and participate in biological processes, including inflammation, immune responses, cell proliferation, and differentiation. During the process of pregnancy, STAT signaling is involved in regulating embryonic implantation, endometrial decidualization, and establishing and maintaining maternal-fetal immune tolerance. Increasing evidence suggests that aberrant STAT signaling contributes to the occurrence and development of pregnancy disorders, including repeated implantation failure (RIF), preeclampsia (PE), recurrent spontaneous abortion (RSA), preterm birth (PTB) and gestational diabetes mellitus (GDM). Elucidating the molecular mechanisms of the STAT signaling pathway holds promise for further understanding the establishment and maintenance of normal pregnancy, and thereby providing potent targets and strategic avenues for the prevention and management of ailments associated with pregnancy. In this review, we summarized the roles of the STAT signaling pathway and its related regulatory function in embryonic implantation, endometrial decidualization, and maternal-fetal immune tolerance. In conclusion, in-depth research on the mechanism of the STAT signaling pathway not only enhances our understanding of normal pregnancy processes but also offers STAT-based therapeutic approaches to protect women from the burden of pregnancy-related disorders.

Injectable collagen hydrogel combines human umbilical cord mesenchymal stem cells to promote endometrial regeneration in rats with thin endometrium

The regeneration of thin endometrium still remains as a great challenge in the field of reproductive medicine. Stem cells-based therapy has been considered as a promising strategy for the restoration of thin endometrium. However, the low transplantation and retention rate of stem cells and loss of stemness due to in vitro expansion limits the therapeutic efficacy. In our study, we combined collagen hydrogel and human umbilical cord mesenchymal stem cells (uMSCs) for improving the regeneration of thin endometrium, by using the potent pluripotency and low immunogenicity of uMSCs and collagen hydrogel that promotes the anchorage and proliferation of stem cells. Results showed that collagen hydrogel has favorable biocompatibility and the capacity to enhance the cell viability and expression of stemness-associated genes (including organic cation/carnitine transporter4 (Oct-4), Nanog homeobox (Nanog) and SRY-box transcription factor 2 (SOX2)) of uMSCs. The combination of collagen hydrogel and uMSCs prolonged the retention time of the constructs in the uterine cavity and improved endometrial thickness compared with uMSCs alone, leading to increase the fertility of the rats with thin endometrium. These highlighted therapeutic prospects of collagen hydrogel combined with uMSCs for the minimally invasive therapy of thin endometrium in the clinic.

Sodium alginate hydrogel integrated with type III collagen and mesenchymal stem cell to promote endometrium regeneration and fertility restoration

A thinner endometrium has been linked to implantation failure, and various therapeutic strategies have been attempted to improve endometrial regeneration, including the use of mesenchymal stem cells (MSCs). However, low survival and retention rates of transplanted stem cells are main obstacles to efficient stem cell therapy in thin endometrium. Collagen type III is a key component of the extracellular matrix, plays a crucial role in promoting cell proliferation and differentiation, and has been identified as the major collagen expressed at the implantation site. Herein, composite alginate hydrogel containing recombinant type III collagen (rCo III) and umbilical cord mesenchymal stem cells are developed. rCo III serves as favorable bioactive molecule, displaying that rCo III administration promotes MSCs proliferation, stemness maintenance and migration. Moreover, rCo III administration enhances cell viability and migration of mouse endometrial stromal cells (ESCs). In a mouse model of thin endometrium, the Alg-rCo III hydrogel loaded with MSCs (MSC/Alg-rCo III) significantly induces endometrial regeneration and fertility enhancement in vivo. Further studies demonstrate that the MSC/Alg-rCo III hydrogel promoted endometrial function recovery partly by regulating mesenchymal-epithelial transition of ESCs. Taken together, the combination of Alg-rCo III hydrogel and MSCs has shown promising results in promoting endometrium regeneration and fertility restoration, and may provide new therapeutic options for endometrial disease.

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

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

Effect of collagen endometrial patch loaded with adipose-derived mesenchymal stem cells on endometrial regeneration in rats with a thin endometrium

Background

This study aimed to investigate the effects of a collagen endometrial patch (EM patch) loaded with adipose-derived mesenchymal stem cells (ADSCs) on endometrial regeneration in a rat model with thin endometrium.

Materials and methods

Thin endometrium was induced in female rats and divided into treatment groups as outlined: control, group 1(G1), local injection of ADSCs into the uterus, group 2 (G2), an EM patch without ADSCs, group 3 (G3), and an EM patch loaded with ADSCs, group 4 (G4). The rats were euthanized at either two weeks or four weeks after modeling and treatment followed by histological and biochemical analyses to examine the regenerative effects on the injured endometrium.

Results

Transplantation of the ADSC-loaded EM patch significantly promoted endometrial proliferation and increased the luminal epithelial area. Two weeks after treatment, the mean number of von Villebrand factor (vWF)+ or cluster of differentiation (CD) 31+-stained blood vessels was significantly higher in G4 than in G1 and G2. The mRNA and protein expression levels of TGF-β and FGF2 were significantly upregulated in G4 compared to those in the control. G4 exhibited significantly increased LIF mRNA levels and immunoreactivity compared with the other groups at both two weeks and four weeks after treatment. Cell tracking after ADSCs treatment revealed the presence of a substantial number of ADSCs grafted in the uterine tissues of G4, whereas a low number of ADSCs that were focally clustered were present in G2.

Conclusion

Transplantation of EM patches loaded with ADSCs resulted in the histological and biochemical restoration of an injured endometrium. The strategic integration of EM patches and ADSCs holds significant promise as an innovative therapeutic approach for effectively treating impaired endometrial conditions.

Exploration of eMSCs with HA-GEL system in repairing damaged endometrium after endometrial cancer with fertility-sparing treatment

Despite the high complete response rate of fertility-sparing treatment in early-stage endometrial cancer (EC), the low pregnancy rate is a clinical challenge. Whether endometrium-derived mesenchymal stem cells (eMSCs) can repair damaged endometrium after EC reversal remains unclear. This study explored the potential therapeutic effects of eMSCs with suitable scaffold materials on endometrial damage caused by EC. Here, appropriate engineering scaffold materials were compared to identify the most suitable materials to carry eMSCs. Then, safety and efficacy evaluations of eMSCs with a suitable hyaluronic acid hydrogel (eMSCs/HA-GEL) were investigated in in vivo experiments with subcutaneous xenotransplantation in Balb/C nude mice and a model of endometrial mechanical injury in rats. HA-GEL has minimal cytotoxicity to eMSCs compared to other materials. Then, in vitro experiments demonstrate that eMSCs/HA-GEL enhance the inhibitory effects of progestins on EC cell biological behaviors. eMSCs/HA-GEL significantly inhibit EC cell growth and have no potential safety hazards of spontaneous tumorigenesis in Balb/C nude mouse subcutaneous xenotransplantation assays. eMSCs/HA-GEL intrauterine transplantation effectively increases endometrial thickness and glandular number, improves endometrial blood supply, reduces fibrotic areas, and improves pregnancy rates in a rat endometrial mechanical injury model. GFP-eMSCs/HA-GEL intrauterine transplantation in rats shows more GFP-eMSCs in the endometrium than GFP-eMSCs transplantation alone, and no tumor formation or suspicious cell nodules are found in the liver, kidney, or lung tissues. Our results reveal the safety and efficacy of eMSCs/HA-GEL in animal models and provide preliminary evidence for the use of eMSCs/HA-GEL as a treatment for EC-related endometrial damage.

Biomimetic Gland Models with Engineered Stratagems

As extensively distributed tissues throughout the human body, glands play a critical role in various physiological processes. Therefore, the construction of biomimetic gland models in vitro has aroused great interest in multiple disciplines. In the biological field, the researchers focus on optimizing the cell sources and culture techniques to reconstruct the specific structures and functions of glands, such as the emergence of organoid technology. From the perspective of biomedical engineering, the generation of biomimetic gland models depends on the combination of engineered scaffolds and microfluidics, to mimic the in vivo environment of glandular tissues. These engineered stratagems endowed gland models with more biomimetic features, as well as a wide range of application prospects. In this review, we first describe the biomimetic strategies for constructing different in vitro gland models, focusing on the role of microfluidics in promoting the structure and function development of biomimetic glands. After summarizing several common in vitro models of endocrine and exocrine glands, the applications of gland models in disease modelling, drug screening, regenerative medicine, and personalized medicine are enumerated. Finally, we conclude the current challenges and our perspective of these biomimetic gland models.

Human endometrium-derived mesenchymal stem/stromal cells application in endometrial-factor induced infertility

Endometrial-factor induced infertility remains one of the most significant pathology among all fertility disorders. Stem cell-based therapy is considered to be the next-generation approach. However, there are still issues about successfully retrieving human endometrium-derived mesenchymal stem/stromal cells (hEnMSCs). Moreover, we need to establish a better understanding of the effect of hEnMSCs on the endometrial recovery and the clinical outcome. According to these challenges we created a multi-step study. Endometrium samples were collected from females undergoing assisted reproductive technology (ART) procedure due to couple infertility. These samples were obtained using an endometrium scratching. The hEnMSCs were isolated from endometrium samples and characterized with flow cytometry analysis. Groups of endometrium injured female mice were established by the mechanical injury to uterine horns and the intraperitoneal chemotherapy. The hEnMSCs suspension was injected to some of the studied female mice at approved time intervals. Histological changes of mice uterine horns were evaluated after Masson's trichrome original staining, hematoxylin and eosin (H&E) staining. The fertility assessment of mice was performed by counting formed embryo implantation sites (ISs). The expression of fibrosis related genes (Col1a1, Col3a1, Acta2, and CD44) was evaluated by the reverse transcription-quantitative polymerase chain reaction (RT-qPCR). Results showed that endometrium scratching is an effective procedure for mesenchymal stem/stromal cells (MSCs) collection from human endometrium. Isolated hEnMSCs met the criteria for defining MSCs. Moreover, hEnMSCs-based therapy had a demonstrably positive effect on the repair of damaged uterine horns, including a reduction of fibrosis, intensity of inflammatory cells such as lymphocytes and polymorphonuclear cells (PMNs) and the number of apoptotic bodies. The injured mice which recieved hEnMSCs had higher fertility in comparison to the untreated mice. Gene expression was reflected in histology changes and outcomes of conception. In conclusion, hEnMSCs demonstrated a positive impact on endometrium restoration and outcomes of endometrial-factor induced infertility. Further exploration is required in order to continue exploring the multifactorial associations between stem cell therapy, gene expression, endometrial changes and reproductive health, so we can identify individually effective and safe treatment strategies for endometrial-factor induced infertility, which is caused by mechanical effect or chemotherapy, in daily clinical practise.

Exploring the future potential of mesenchymal stem/stromal cells and their derivatives to support assisted reproductive technology for female infertility applications

Women's infertility impacts the quality of life of both patients and couples and has multifaceted dimensions that increase the number of challenges associated with female infertility and how to face them. Female reproductive disorders, such as premature ovarian failure (POF), endometriosis, Asherman syndrome (AS), polycystic ovary syndrome (PCOS), and preeclampsia, can stimulate infertility. In the last decade, translational medicine has advanced, and scientists are focusing on infertility therapy with innovative attitudes. Recent investigations have suggested that stem cell treatments could be safe and effective. Stem cell therapy has established a novel method for treating women's infertility as part of a regeneration approach. The chief properties and potential of mesenchymal stem/stromal cells (MSCs) in the future of women's infertility should be considered by researchers. Due to their high abundance, great ability to self-renew, and high differentiation capacity, as well as less ethical concerns, MSC-based therapy has been found to be an effective alternative strategy to the previous methods for treating female infertility, such as intrauterine insemination, in vitro fertilization, medicines, and surgical procedures. These types of stem cells exert their beneficial role by releasing active mediators, promoting cell homing, and contributing to immune modulation. Here we first provide an overview of MSCs and their crucial roles in both biological and immunological processes. The next large chapter covers current preclinical and clinical studies on the application of MSCs to treat various female reproductive disorders. Finally, we deliberate on the extant challenges that hinder the application of MSCs in female infertility and suggest plausible measures to alleviate these impediments.

Treatment strategies for intrauterine adhesion: focus on the exosomes and hydrogels

Intrauterine adhesion (IUA), also referred to as Asherman Syndrome (AS), results from uterine trauma in both pregnant and nonpregnant women. The IUA damages the endometrial bottom layer, causing partial or complete occlusion of the uterine cavity. This leads to irregular menstruation, infertility, or repeated abortions. Transcervical adhesion electroreception (TCRA) is frequently used to treat IUA, which greatly lowers the prevalence of adhesions and increases pregnancy rates. Although surgery aims to disentangle the adhesive tissue, it can exacerbate the development of IUA when the degree of adhesion is severer. Therefore, it is critical to develop innovative therapeutic approaches for the prevention of IUA. Endometrial fibrosis is the essence of IUA, and studies have found that the use of different types of mesenchymal stem cells (MSCs) can reduce the risk of endometrial fibrosis and increase the possibility of pregnancy. Recent research has suggested that exosomes derived from MSCs can overcome the limitations of MSCs, such as immunogenicity and tumorigenicity risks, thereby providing new directions for IUA treatment. Moreover, the hydrogel drug delivery system can significantly ameliorate the recurrence rate of adhesions and the intrauterine pregnancy rate of patients, and its potential mechanism in the treatment of IUA has also been studied. It has been shown that the combination of two or more therapeutic schemes has broader application prospects; therefore, this article reviews the pathophysiology of IUA and current treatment strategies, focusing on exosomes combined with hydrogels in the treatment of IUA. Although the use of exosomes and hydrogels has certain challenges in treating IUA, they still provide new promising directions in this field.

Network Pharmacology Analysis of the Mechanisms Underlying the Therapeutic Effects of Yangjing Zhongyu Tang on Thin Endometrium

Purpose

Yangjing Zhongyu Tang (YJZYT) is a classic Chinese prescription for infertility treatment and exerts therapeutic effects via activity on the thin endometrium (TE). However, the major components and underlying mechanisms of YJZYT actions remain to be established. The main objectives of this study were to clarify the effects of YJZYT on the TE and provide insights into the related mechanisms based on network pharmacology and molecular docking analyses.

Methods

Network pharmacology was employed to explore the main bioactive components and targets of YJZYT. TE-related genes were obtained from the Genecards database and screened for intersections with YJZYT. The Cytoscape 3.8.2 was used to build a "compounds-disease-targets" network and molecular docking analysis performed on key targets. The mechanism of action of YJZYT was further validated in vivo using a rat model.

Results

A total of 98 YJZYT active ingredients, 2409 thin endometrium-associated genes, and 186 common targets were obtained. Through topological analysis, 10 core objectives were screened. Data from the PPI network suggest that AKT1, TNF, VEGFA, IL-6, TP53, INS, ESR1, MMP9, ALB, and ACTB serve as key targets in the action of YJZYT on TE. PI3K-Akt, TNF, apoptosis, IL-17 and MAPK were established as the main functional pathways. Molecular docking analysis revealed high affinity of the active ingredients of YJZYT, specifically, ursolic acid, palbinone, stigmasterol, and beta-sitosterol, for TNF, VEGFA, IL-6, AKT, and MMP9. YJZYT improved endometrial recovery, promoted endometrial angiogenesis, and upregulated protein expression of VEGF, PI3K, AKT, and p-AKT in the TE rat model.

Conclusion

Network pharmacological and animal studies facilitated the prediction and validation of the active components and key targets of YJZYT potentially contributing to TE. Preliminary evidence from in vivo experiments showed that YJZYT promotes angiogenesis and thin endometrial repair via regulation of the PI3K/AKT pathway, providing a reference for further research.

Functionalized Human Umbilical Cord Mesenchymal Stem Cells and Injectable HA/Gel Hydrogel Synergy in Endometrial Repair and Fertility Recovery

Intrauterine adhesions (IUA) caused by endometrial injury are one of the main causes of female infertility. The current treatments for endometrial injury offer limited clinical benefits and cannot improve endometrial receptivity and pregnancy outcomes. Tissue engineering and regenerative medicine are considered potential solutions to address this concern and may offer effective treatment methods for the regeneration of injured human endometrium. Herein, we prepared an injectable hydrogel based on oxidized hyaluronic acid (HA-CHO) and hydrazide-grafted gelatin (Gel-ADH). The injectable hydrogel showed satisfactory biocompatibility when mixed with human umbilical cord mesenchymal stem cells (hUCMSCs). In an endometrial injury rat model, the treatment with hUCMSCs-loaded injectable hydrogel significantly enhanced the thickness of the endometrium and increased the abundance of blood vessels and glands in the injured endometrium compared to the control group. The hUCMSCs-loaded injectable hydrogel treatment significantly reduced endometrial fibrosis, decreased the expression of the pro-inflammatory factors (IL-1β and IL-6) and increased the expression of the anti-inflammatory factor (IL-10). This treatment induced endometrial VEGF expression by activating the MEK/ERK1/2 signaling pathway. Moreover, this treatment improved endometrial receptivity to the embryo and restored the embryo implantation rate similar to the sham group (48% in the sham group vs 46% in the treatment group), and this treatment achieved pregnancy and live birth in rats with endometrial injury. In addition, we also preliminarily validated the safety of this treatment in the maternal rats and fetuses. Collectively, our study showed that the hUCMSCs-loaded injectable hydrogel hold potential as an effective treatment strategy promoting rapid recovery of endometrial injury, and this hydrogel is a promising biomaterial for regenerative medicine applications. STATEMENT OF SIGNIFICANCE: : 1. Oxidized hyaluronic acid (HA-CHO)/hydrazide-grafted gelatin (Gel-ADH) hydrogel combined with human umbilical cord mesenchymal stem cells (hUCMSCs) are effective in improving the regeneration of endometrium in the endometrial injury rat model. 2. The hUCMSCs-loaded hydrogel treatment promotes the expression of endometrial VEGF through MEK/ERK1/2 signaling pathway and regulates the balance of inflammatory factors. 3. The embryo implantation and live birth rates restore to normal level in the endometrial injury rat model, and the hydrogel has no adverse effects on maternal rats, fetuses, and offspring development after the treatments.

Macromolecule-based hydrogels nanoarchitectonics with mesenchymal stem cells for regenerative medicine: A review

The role of regenerative medicine in clinical therapies is becoming increasingly vital. Under specific conditions, mesenchymal stem cells (MSCs) are capable of differentiating into mesoblastema (i.e., adipocytes, chondrocytes, and osteocytes) and other embryonic lineages. Their application in regenerative medicine has attracted a great deal of interest among researchers. To maximize the potential applications of MSCs, materials science could provide natural extracellular matrices and provide an effective means to understand the various mechanisms of differentiation for the growth of MSCs. Pharmaceutical fields are represented among the research on biomaterials by macromolecule-based hydrogel nanoarchitectonics. Various biomaterials have been used to prepare hydrogels with their unique chemical and physical properties to provide a controlled microenvironment for the culture of MSCs, laying the groundwork for future practical applications in regenerative medicine. This article currently describes and summarizes the sources, characteristics, and clinical trials of MSCs. In addition, it describes the differentiation of MSCs in various macromolecule-based hydrogel nanoarchitectonics and highlights the preclinical studies of MSCs-loaded hydrogel materials in regenerative medicine conducted over the past few years. Finally, the challenges and prospects of MSC-loaded hydrogels are discussed, and the future development of macromolecule-based hydrogel nanoarchitectonics is outlined by comparing the current literature.

Exosome-Based Regimen Rescues Endometrial Fibrosis in Intrauterine Adhesions Via Targeting Clinical Fibrosis Biomarkers

Intrauterine adhesions (IUA), which is characterized by endometrial fibrosis, continue to be the most common cause of uterine infertility globally. Our work revealed that 3 fibrotic progression markers (Vimentin, COL5A2, and COL1A1) were significantly increased in the endometrium of IUA patients. Mesenchymal stem cell-derived exosomes (EXOs) have been recently revealed as a cell-free therapy for fibrosis diseases. Nevertheless, the application of EXOs is restricted by the short residency duration in the target tissue. To overcome this limitation, herein, we reported an exosome-based regimen (EXOs-HP) that thermosensitive poloxamer hydrogel possessed the ability to efficiently promote the residency duration of EXOs in the uterine cavity. By downregulating fibrotic progression markers (Vimentin, COL5A2, and COL1A1), EXOs-HP could significantly restore the function and structure of the injured endometrium in the IUA model. Our work provides the theoretical and experimental foundation of EXOs-HP in treating IUA, highlighting the clinical potential of topical EXOs-HP delivery system in IUA patients.

β-Lactoglobulin affects the oxidative status and viability of equine endometrial progenitor cells via lncRNA-mRNA-miRNA regulatory associations

The β-lactoglobulin (β-LG) was previously characterized as a mild antioxidant modulating cell viability. However, its biological action regarding endometrial stromal cell cytophysiology and function has never been considered. In this study, we investigated the influence of β-LG on the cellular status of equine endometrial progenitor cells under oxidative stress. The study showed that β-LG decreased the intracellular accumulation of reactive oxygen species, simultaneously ameliorating cell viability and exerting an anti-apoptotic effect. However, at the transcriptional level, the reduced mRNA expression of pro-apoptotic factors (i.e. BAX and BAD) was accompanied by decreased expression of mRNA for anti-apoptotic BCL-2 and genes coding antioxidant enzymes (CAT, SOD-1, GPx). Still, we have also noted the positive effect of β-LG on the expression profile of transcripts involved in endometrial viability and receptivity, including ITGB1, ENPP3, TUNAR and miR-19b-3p. Finally, the expression of master factors of endometrial decidualization, namely prolactin and IGFBP1, was increased in response to β-LG, while non-coding RNAs (ncRNAs), that is lncRNA MALAT1 and miR-200b-3p, were upregulated. Our findings indicate a novel potential role of β-LG as a molecule regulating endometrial tissue functionality, promoting viability and normalizing the oxidative status of endometrial progenitor cells. The possible mechanism of β-LG action includes the activation of ncRNAs essential for tissue regeneration, such as lncRNA MALAT-1/TUNAR and miR-19b-3p/miR-200b-3p.

Repairing and Regenerating Injured Endometrium Methods

Good endometrium is the prerequisite and guarantee for reproduction and maternal and child health. Endometrial injury caused by operation or non-operation can lead to menstrual irregularities, amenorrhea, abortion, infertility, and other gynecological diseases to bother women. Intrauterine adhesions (IUA) and thin endometrium are common diseases caused by abnormal repair after endometrium damage. The incidence of IUA is not low after uterine operative surgery, and the recurrence is pretty high after uterine adhesiolysis. At present, there were many methods for endometrial repair in clinic or in the laboratory, but the efficacy was different from methods to methods. They are mainly including estrogen therapy, stem cell therapy, complementary medicine therapy, and some physical barrier therapy. In order to guide the effective repair and regeneration of endometrium in clinic, this paper reviews the merit and demerit of these methods for endometrium regeneration and repair that have been proved to be effective in experiments and clinical in recent years.

Fibroblast growth factor 1 ameliorates thin endometrium in rats through activation of the autophagic pathway

Background: Thin endometrium is a reproductive disorder that affects embryo implantation. There are several therapies available for this disease, however they are not so effective. Fibroblast growth factor 1 (FGF1) is a member of fibroblast growth factor superfamily (FGFs), and it has been demonstrated that FGF1 expression was altered in samples collected from patients with thin endometrium. However, it is unclear if FGF1 could improve thin endometrium. The aim of this study was to investigate whether FGF1 have a therapeutic effect on thin endometrium. Methods: A model of thin endometrium induced by ethanol was constructed to investigate the effect and mechanism of action of FGF1 in thin endometrium. In the characterization experiments, 6-8 weeks female rats (n = 40) were divided into four groups: i) Control group; ii) Sham group; iii) Injured group; (iv) FGF1 therapy group. Endometrial tissues would be removed after three sexuel cycles after molding. Morphology and histology of the endometrium were evaluated by visual and hematoxylin and eosin staining. Masson staining and expression of α-SMA in endometrium showed the degree of endometrial fibrosis. Western blotting (PCNA、vWF and Vim) and immunohistochemistry (CK19 and MUC-1) demonstrated the effect of FGF1 on cell proliferation and angiogenesis. Moreover, immunohistochemistry (ER and PR) was used to explore the function of endometrium. The remaining rats (n = 36) were divided into three groups: i) Injured group; ii) FGF1 therapy group; and iii) 3-methyladenine. Western blotting (p38、p-p38、PI3K 、SQSTM1/p62、beclin-1 and LC3) was used to explore the mechanisms of FGF1. Results: In FGF1 therapy group, the morphology and histology of endometrium improved compared with the model group. Masson staining and the expression level of α-SMA showed that FGF1 could decrease the fibrotic area of endometrium. Besides, changes in ER and PR expression in the endometrium suggested that FGF1 could restore endometrium-related functions. Western blotting and immunohistochemistry revealed that PCNA, vWF, Vim, CK19 and MUC-1 were significantly increased after FGF1 treatment compared with the thin endometrium. In addition, Western blotting showed that p38, p-p38, PI3K, SQSTM1/p62, beclin-1 and LC3 levels were higher in FGF1 group than in the injured group. Conclusion: FGF1 application cured the thin endometrium caused by ethanol through autophagy mechanism.

Recent Developments in Biomaterial-Based Hydrogel as the Delivery System for Repairing Endometrial Injury

Endometrial injury caused by intrauterine surgery often leads to pathophysiological changes in the intrauterine environment, resulting in infertility in women of childbearing age. However, clinical treatment strategies, especially for moderate to severe injuries, often fail to provide satisfactory therapeutic effects and pregnancy outcomes. With the development of reproductive medicine and materials engineering, researchers have developed bioactive hydrogel materials, which can be used as a physical anti-adhesion barrier alone or as functional delivery systems for intrauterine injury treatment by loading stem cells or various active substances. Studies have demonstrated that the biomaterial-based hydrogel delivery system can provide sufficient mechanical support and improve the intrauterine microenvironment, enhance the delivery efficiency of therapeutic agents, prolong intrauterine retention time, and perform efficiently targeted repair compared with ordinary drug therapy or stem cell therapy. It shows the promising application prospects of the hydrogel delivery system in reproductive medicine. Herein, we review the recent advances in endometrial repair methods, focusing on the current application status of biomaterial-based hydrogel delivery systems in intrauterine injury repair, including preparation principles, therapeutic efficacy, repair mechanisms, and current limitations and development perspectives.