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

A double network composite hydrogel with enhanced transdermal delivery by ultrasound for endometrial injury repair and fertility recovery

Endometrial injury and resulting female infertility pose significant clinical challenges due to the notable shortcomings of traditional treatments. Herein, we proposed a double network composite hydrogel, CSMA-RC-Zn-PNS, which forms a physical barrier on damaged tissue through photo-crosslinking while enabling sustained release of the active ingredient PNS. Based on this, we developed a combined strategy to enhance transdermal delivery efficiency using ultrasound cavitation. In vitro experiments demonstrated that CSMA-RC-Zn-PNS exhibits excellent biosafety, biodegradability, and promotes cell proliferation, migration, and tube formation, along with antioxidant and antibacterial properties. In a rat endometrial injury model, the ultrasound cavitation effect was demonstrated to enhance transdermal delivery efficiency, and the ability of CSMA-RC-Zn-PNS to promote endometrial regeneration, anti-fibrosis and fertility restoration was verified. Overall, this strategy combining CSMA-RC-Zn-PNS hydrogel and ultrasound treatment shows promising applications in endometrial regeneration and female reproductive health.

Novel therapeutic strategies for Asherman's syndrome: Endometrial regeneration using menstrual blood-derived stem cells

Endometrium is vital to the establishment of pregnancy through its cyclical regeneration, which, when disrupted, can lead to endometrial thinning and Asherman's syndrome (AS). AS is characterized by infertility, pelvic pain, menstrual irregularities, and placental complications. Currently, treatments such as hysteroscopic adhesiolysis and hormone replacement therapy have demonstrated variable efficacy with limited clinical evidence. Recent developments in cell therapy have introduced menstrual blood-derived mesenchymal stem cells (MenSCs) as a promising alternative therapeutic strategy. Menstrual blood offers a noninvasive, periodically available source of mesenchymal stem cells, MenSCs for endometrial regeneration. This review comprehensively examines the endometrial regenerative process, pathophysiology of AS, and therapeutic prospects of MenSCs, underscoring the need for continued research to optimize treatment strategies.

Umbilical cord-derived mesenchymal stem cells combined with kaempferol synergistically promote repair of damaged endometrium by modulating JAK2/STAT3 signaling pathway

Intrauterine adhesion (IUA) is a disease caused by endometrial damage without effective treatments. Stem cell therapy has been initiated as a new attempt to repair and regenerate injured tissues. However, the therapeutic efficacy of stem cell therapy is limited. Kaempferol is a natural flavonoid with various beneficial effects. In this study, our goal is to investigate the roles of kaempferol combined with umbilical cord-derived mesenchymal stem cells (UCMSCs) in IUA. UCMSCs were collected from human umbilical cords. The multilineage differentiation potential of human UCMSCs was evaluated by Oil Red O staining, Alizarin Red S staining, and Alcian Blue staining. The phenotype profile of human UCMSCs was assessed by flow cytometry. CCK-8 and Transwell assays were performed to detect cell viability and migration. The IUA rat model was established. Histological changes were examined by hematoxylin-eosin staining and Masson staining. Gene expression was evaluated by western blotting and immunofluorescence. Kaempferol (10 μM) promoted the migration and proliferation of human UCMSCs in vitro. Additionally, kaempferol/UCMSCs combination treatment recovered endometrial injury and inhibited endometrial fibrosis and epithelial-mesenchymal transition occurrence in IUA rat models. Mechanistically, kaempferol/UCMSCs combination treatment inhibited JAK2/STAT3 pathway. Kaempferol/UCMSCs combination treatment can promote the repair of damaged endometrium by decreasing endometrial fibrosis. The inactivation of JAK2/STAT3 pathway is greatly responsible for the protective effect of kaempferol/UCMSCs combination treatment.

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

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

JHP-7 (QLLEELKR), a heptapeptide derived from Jinhua ham, may ameliorate intrauterine adhesion (IUA) via inhibiting inflammatory response and apoptosis

OBJECTIVE

This study aimed to investigate the effect of JHP-7(QLLEELKR) derived from Jinhua ham on IUA, in order to provide new methods and new ideas for the clinical treatment of IUA.

METHODS

The JHP-7 was synthesized by solid-phase peptide synthesis (SPPS). An in vitro model (human endometrial epithelial cells (HEECs) induced by 10 ng/mL TGF-β1) and an in vivo model (C57BL/6 mice induced by mechanical curettage and LPS stimulation) were used in the study. In vitro, HEEC were co-cultured with TGF-β1with or without JHP-7 (1 μM and 10 μM) for 48 h, followed by RT-qPCR and Western blotting analysis. Meanwhile, the fluorescent ROS probe was employed to assess oxidative stress levels. In vivo, IUA mice were preventively treated with JHP-7 (150 μg/kg/d and 300 μg/kg/d) for 14 days, after which uterine tissues were collected for histopathological evaluation using H&E and Masson staining, as well as molecular analysis via RT-qPCR and Western blotting to measure mRNA and protein expression levels.

RESULTS

In vitro, JHP-7 significantly inhibited the expression of proinflammatory and fibrosis markers, reduced the ROS, and protected endometrial function. Further studies showed that JHP-7 inhibited the apoptosis of TGF-β1-induced HEECs, and reduced the expression of TLR4, p-NF-κB, and p-MAPK. In vivo, JHP-7 significantly improved the uterine morphology and reduced collagen deposition in IUA mice. Reduced expression of TLR4, MyD88, p-NF-κB, p-MAPK and up-regulating expression of Bcl2 were also detected after JHP-7 treatment.

CONCLUSION

JHP-7 could ameliorate IUA via inhibiting inflammation and apoptosis, which may be related to the TLR4/MyD88/MAPK/NF-κB signaling pathway.

Therapeutic strategies: Bioactive hydrogels oxidized sodium alginate/strontium/betamethasone for preventing intrauterine adhesion

Intrauterine adhesion (IUA) is an endometrial damage repair disorder that leads to menstrual loss, amenorrhea, and infertility in women; therefore, addressing this dilemma is a critical challenge. In this study, a multifunctional hydrogel, comprising oxidized sodium alginate (OSA), strontium carbonate (SrCO3), and betamethasone 21-phosphate sodium (BSP), was formulated to facilitate angiogenesis, reduce fibrosis, and support tissue repair in the treatment of IUA. The composite hydrogels showed significant bioactivity on human endometrial stromal cells (HESCs) and human umbilical vein endothelial cells (HUVECs), promoting the injured HESCs repair, reversing the degree of fibrosis to a certain extent, and enhancing the proliferation and migration of HUVECs. These results were also verified in the IUA model of sexually mature female rats. Compared with the model group, the selection of the appropriate hydrogel significantly increased endometrial thickness (p < 0.01), the number of glands (p < 0.001), decreased the degree of fibrosis (p < 0.05), and Vimentin (p < 0.01), CK19 (p < 0.01), CD31 (p < 0.01), and Ki67 (p < 0.01) molecular expression increased remarkably. In summary, in situ injection of this multifunctional hydrogel into the uterine cavity not only serves as a physical barrier, isolating the damaged endometrium, but also gradually releases drugs as the hydrogel degrades. This multifunctional hydrogel promotes endometrial proliferation and angiogenesis while reducing fibrosis, and provides therapeutic strategies for patients with clinical IUA.

Progress in Polysaccharide-Based Hydrogels for Preventing Postoperative Adhesions: A Review

Postoperative adhesions are common complications following surgery, often accompanied by pain and inflammation that significantly diminish patients' quality of life. Moreover, managing postoperative adhesions incurs substantial cost, imposing a considerable financial burden on both patients and healthcare systems. Traditional anti-adhesion materials are confronted with limitations, such as inadequate tissue adherence in a moist environment and poor degradability, underscoring the urgent need for more effective solutions. Recently, polysaccharide-based hydrogels have received considerable attention for their potential in preventing postoperative adhesions. The hydrogels not only facilitate wound healing but also effectively reduce inflammation, providing a promising approach to preventing postoperative adhesions. This review provides an extensive analysis of the progress made in the development of polysaccharide-based hydrogels for postoperative anti-adhesion therapy. It highlights their principal benefits, outlines future research trajectories, and addresses the ongoing challenges that need to be overcome.

Endothelial senescence induced by PAI-1 promotes endometrial fibrosis

Intrauterine adhesions (IUAs), also known as Asherman's syndrome (AS), represent a significant cause of uterine infertility for which effective treatment remains elusive. The endometrium's ability to regenerate cyclically depends heavily on the growth and regression of its blood vessels. However, trauma to the endometrial basal layer can disrupt the subepithelial capillary plexus, impeding regeneration. This damage results in the replacement of native cells with fibroblasts and myofibroblasts, ultimately leading to fibrosis. Endothelial cells (ECs) play a pivotal role in the vascular system, extending beyond their traditional barrier function. Through single-cell sequencing and experimental validation, we discovered that ECs undergo senescence in IUA patients, impairing angiogenesis and fostering stromal cell fibrosis. Further analysis revealed significant interactions between ECs and PAI-1+ stromal cells. PAI-1, derived from stromal cells, promotes EC senescence via the urokinase-type plasminogen activator receptor (uPAR). Notably, prior to fibrosis onset, TGF-β upregulates PAI-1 expression in stromal cells in a SMAD dependent manner. In an IUA mouse model, inhibiting PAI-1 mitigated EC senescence and endometrial fibrosis. Our findings underscore the crucial role of EC senescence in IUA pathogenesis, contributing to vascular reduction and fibrosis. Targeting PAI-1 represents a promising therapeutic strategy to suppress EC senescence and alleviate endometrial fibrosis, offering new insights into the treatment of IUAs.

Smart design in biopolymer-based hemostatic sponges: From hemostasis to multiple functions

Uncontrolled hemorrhage remains the leading cause of death in clinical and emergency care, posing a major threat to human life. To achieve effective bleeding control, many hemostatic materials have emerged. Among them, nature-derived biopolymers occupy an important position due to the excellent inherent biocompatibility, biodegradability and bioactivity. Additionally, sponges have been widely used in clinical and daily life because of their rapid blood absorption. Therefore, we provide the overview focusing on the latest advances and smart designs of biopolymer-based hemostatic sponge. Starting from the component, the applications of polysaccharide and polypeptide in hemostasis are systematically introduced, and the unique bioactivities such as antibacterial, antioxidant and immunomodulation are also concerned. From the perspective of sponge structure, different preparation processes can obtain unique physical properties and structures, which will affect the material properties such as hemostasis, antibacterial and tissue repair. Notably, as development frontier, the multi-functions of hemostatic materials is summarized, mainly including enhanced coagulation, antibacterial, avoiding tumor recurrence, promoting tissue repair, and hemorrhage monitoring. Finally, the challenges facing the development of biopolymer-based hemostatic sponges are emphasized, and future directions for in vivo biosafety, emerging materials, multiple application scenarios and translational research are proposed.

Hysteroscopic Endometrial Defect Following Adenomyomectomy and Incidence of Placenta Accreta Spectrum and Uterine Rupture Complications for Subsequent Pregnancy

Adenomyomectomy, a therapeutic option for women with adenomyosis who wish to preserve their fertility, has been reported to pose a risk of developing placenta accreta spectrum (PAS) and uterine rupture in future pregnancies. However, the specific clinical factors contributing to these occurrences remain elusive. This study aimed to explore the association between hysteroscopic findings after adenomyomectomy and the incidence of PAS in subsequent pregnancies. We conducted a retrospective analysis of 10 patients (11 pregnancies) who had undergone hysteroscopy following adenomyomectomy and had later delivered at our hospital. In 6/10 patients, postoperative hysteroscopy revealed endometrial defects. However, subsequent evaluations confirmed endometrial restoration within 7-21 months, with five patients achieving pregnancy afterward. The only other patient conceived naturally without waiting for endometrial restoration, resulting in uterine rupture from the site of the placenta percreta. The incidence of clinically diagnosed PAS during cesarean section was 100% (1/1) in pregnancies with preconceptional endometrial defects, 20% (1/5) in those with endometrial restoration, and 0% (0/5) in pregnancies without endometrial defects. Similarly, the incidence of pathologically diagnosed PAS was 100% (1/1), 60% (3/5), and 20% (1/5) in these groups, respectively. Thus, endometrial defects were frequently detected after adenomyomectomy and recovered over time, whereas one patient without endometrial restoration developed uterine rupture complicated by PAS. This study demonstrates that while the presence of an endometrial defect identified by postoperative hysteroscopy may be a risk factor for the occurrence of PAS in subsequent pregnancies, allowing sufficient recovery time for the endometrium may help reduce the risk of uterine rupture.

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.

Integrating Network Pharmacology and In Vitro Experimental Verification Revealing Bushenhuoxue Recipe Against Intrauterine Adhesions via PI3K-AKT Signaling Pathway

We aimed to investigate therapeutic effect of Bushenhuoxue recipe in intrauterine adhesions (IUA) and explore the underlying molecular mechanism via integrating network pharmacology and in vitro experimental verification. The active compounds and gene targets of Bushenhuoxue recipe were screened in the TCMSP database and the IUA-related genes were identified using GeneCards database by the keyword "Intrauterine adhesions". Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis were conducted to reveal the underlying molecular mechanism of Bushenhuoxue recipe treating IUA. T-HESC cells were inducted to fibrotic state using TGF-β1 of 10 ng/ml concentration treating for 24 h. RT-qPCR or western blot was used to demonstrate the expression levels of fibrosis markers (COL1A1 and α-SMA) and KEGG pathway markers. Cell counting kit-8 (CCK8) assay was performed to illustrate the cell viability of endometrial stromal cell. The treatment of Bushenhuoxue recipe could significantly inhibit the proliferation and fibrosis of endometrial stromal cells. We obtained a total of 169 no-repeat ingredients of Bushenhuoxue recipe and 3044 corresponding targets. After taking intersection with 4230 no-repeat IUA-related genes, a total of 83 target genes related to both Bushenhuoxue recipe and IUA were finally identified. KEGG analysis found that PI3K-AKT signaling pathway might be the key pathway. Further experiment revealed that PI3K-AKT signaling pathway was significantly activated in endometrial stromal cells of fibrotic state and the treatment of Bushenhuoxue recipe could inhibit the PI3K-AKT signaling pathway. Further rescue assay demonstrated that Bushenhuoxue recipe suppressed the proliferation and fibrosis of endometrial stromal cells via PI3K-AKT signaling pathway. Bushenhuoxue recipe suppresses the proliferation and fibrosis of endometrial stromal cells via PI3K-AKT signaling pathway, eventually inhibiting the progression of IUA.

Restoration of Pregnancy Function Using a GT/PCL Biofilm in a Rabbit Model of Uterine Injury

Biomaterial scaffolds have been used successfully to promote the regenerative repair of small endometrial lesions in small rodents, providing partial restoration of gestational function. The use of rabbits in this study allowed us to investigate a larger endometrial tissue defect and myometrial injury model. A gelatin/polycaprolactone (GT/PCL) gradient-layer biofilm was sutured at the defect to guide the reconstruction of the original tissue structure. Twenty-eight days postimplantation, the uterine cavity had been restored to its original morphology, endometrial growth was accompanied by the formation of glands and blood vessels, and the fragmented myofibers of the uterine smooth muscle had begun to resemble the normal structure of the lagomorph uterine cavity, arranging in a circular luminal pattern and a longitudinal serosal pattern. In addition, the repair site supported both embryonic implantation into the placenta and normal embryonic development. Four-dimensional label-free proteomic analysis identified the cell adhesion molecules, phagosome, ferroptosis, rap1 signaling pathways, hematopoietic cell lineage, complement and coagulation cascades, tricarboxylic acid cycle, carbon metabolism, and hypoxia inducible factor (HIF)-1 signaling pathways as important in the endogenous repair process of uterine tissue injury, and acetylation of protein modification sites upregulated these signaling pathways.

The Combination of Super-Active Platelet Lysate and Acellular Amniotic Membrane Enhances Endometrial Receptivity, While Simultaneously Facilitating Endometrial Repair in Rats

Purpose

To investigate the combined effects of super-active platelet lysate (sPL) and acellular amniotic membrane (AAM) in promoting endometrial repair and enhancing endometrial receptivity in rats.

Methods

The characteristics of sPL-AAM were examined through scanning electron microscopy, contact angle tester, and release experiments. We aimed to establish a rat model for endometrial injury. We divided sixty-four rats into four groups: the Injury group (Control group), the AAM group, the sPL group, and the sPL-AAM group. Our study compared the endometrial thickness, gland count, and fibrotic area recovery in rats at 6 days and 18 days post-treatment. Immunohistochemistry was utilized to assess the expressions of CD34 and ANG. Additionally, we used ELISA to detect the levels of IL-6 and TNF-α, while Western Blot was employed to compare the expressions of CK19, Integrin β3, and TGF-β1. One month after the treatment, we evaluated and compared the pregnancy recovery among the groups.

Results

Compared to the Injury group, the sPL-AAM group demonstrated enhanced endometrial regeneration in rats at both 6 days and 18 days post-treatment, resulting in a favorable pregnancy outcome. This was achieved by promoting angiogenesis, suppressing the inflammatory response, and reducing fibrosis. The observed effects were superior to those of the sPL group alone. While sPL, when administered alone, showed some degree of endometrial restoration at 6 days post-treatment, its efficacy was diminished at 18 days post-treatment. The impact of AAM alone appeared inconspicuous compared to the injury group. This suggests that sPL serves as the primary agent in facilitating endometrial repair, while AAM functions as a carrier to extend the duration of sPL's effectiveness.

Conclusion

sPL-AAM can release effective cytokines, repair endometrial damage in rats, enhance endometrial receptivity, and ultimately improve pregnancy outcomes.

Engraftment of self-renewing endometrial epithelial organoids promotes endometrial regeneration by differentiating into functional glands in rats

Introduction

Extensive trauma frequently disrupts endometrial regeneration by diminishing endometrial stem cells/progenitor cells, affecting female fertility. While bone marrow mesenchymal stem cell (BMSC) transplantation has been suggested as an approach to address endometrial injury, it comes with certain limitations. Recent advancements in endometrial epithelial organoids (EEOs) have displayed encouraging potential for endometrial regeneration. Therefore, this study aims to explore whether EEOs surpass BMSCs in their ability to repair injured endometrium and to examine whether the restoration process involves the integration of EEOs into the endometrial tissue of the recipient.

Methods

We developed rat EEOs (rEEOs) mimicking the features of the rat endometrium. Subsequently, we created a rat model of endometrial injury to compare the effects of rEEOs and rat BMSCs (rBMSCs) on endometrial regeneration and reproductive recovery. Bulk RNA-sequencing analysis was conducted to further investigate the capacity of rEEOs for endometrial regeneration and to identify discrepancies between rEEOs and rBMSCs. Additionally, to track the fate of the transplanted cells in vivo, we transplanted green fluorescent protein (GFP) -labelled rEEOs or red fluorescent protein (RFP) -labelled rBMSCs.

Results

In a rat model of endometrial injury, we observed that fertility recovery in rats transplanted with rEEOs was more comparable to that of normal rats than in those treated with rBMSC. rEEOs possess a high concentration of endometrial epithelial stem/progenitor cells and secrete vascular endothelial growth factor (VEGF)-A to promote endometrial neovascularization. Significantly, we observed that cells from GFP-labelled rEEOs could integrate and differentiate into functional glands within the injured endometrium of recipient rats.

Discussion

EEOs offer a transformative approach to address the challenges of endometrial trauma. Their remarkable regenerative potential holds promise for the restoration of damaged endometrium. As we venture into the future, the concept of utilizing patient-specific EEOs for transplantation emerges as a tantalizing prospect. However, the EEOs in our experiments were mainly cultured in Matrigel, which has barriers to clinical translation as a biomaterial, a new biomaterial to be explored. Secondly, our experiments have been successful only in rat models, and more efforts need to be made before clinical translation.

Interceed combined with bone marrow mesenchymal stem cells improves endometrial receptivity of intrauterine adhesion

Background

This study aimed to investigate the impact of intrauterine adhesions (IUA) therapy and endometrial receptivity by implanting autologous bone marrow mesenchymal stem cells (BMSCs) into the Interceed and subsequently placing them in the uterine cavity of rats.

Methods

Fifty rats were divided into 5 groups according to the random number table method (10 rats in each group). Following the development of the IUA model through mechanical injury, the animals were categorized into different treatment groups: the IUA model (intrauterine perfusion of saline), Interceed therapy (intrauterine placement of Interceed), BMSCs therapy (intrauterine perfusion of BMSCs), BMSCs + Interceed therapy (intrauterine placement of BMSCs + Interceed), and a control group (intrauterine perfusion of saline). The Hematoxylin-eosin (HE) staining technique was employed to identify and assess the pathological alterations in the endometrium. Additionally, it facilitated the quantification of endometrial glands and the determination of endometrial thickness. Masson staining was used to detect fibrosis in rat uterus. The number of microvascular density (MVD) was detected by immunohistochemistry (IHC). Real-time quantitative reverse transcription polymerase chain reaction (qRT-PCR) and Western blot were used to detect the levels of leukemia inhibitory factor (LIF), integrin ανβ3, and vascular endothelial growth factor (VEGF) in uterine tissue. Male and female rats were combined in cages for reproductive and conception evaluation.

Results

In comparison to the control, the number of endometrial glands in the IUA model was significantly reduced, and the degree of endometrial thinning and fibrosis was significantly increased (p < 0.05). Compared with the IUA model, the number of endometrial glands did not exhibit any significant alterations in endometrial thickness and MVD number. The expressions of LIF, integrin ανβ3, and VEGF in the uterine tissue were not significantly improved with Interceed therapy, resulting in no significant improvement in the pregnancy rate (p > 0.05). The number of endometrial glands, endometrial thickness, and MVD in the BMSCs therapy group were significantly increased. Moreover, the expressions of LIF, integrin ανβ3, and VEGF in uterine tissue exhibited a significant increase, leading to a comparatively higher pregnancy rate (p < 0.05). In the BMSCs + Interceed therapy group, the number of endometrial glands, endometrial thickness, and MVD were significantly increased, and the expressions of LIF, integrin ανβ3, and VEGF in uterine tissue were significantly increased as well, along with a corresponding rise in the pregnancy rate (p < 0.05).

Conclusion

The intrauterine placement of Interceed combined with BMSCs in IUA rats can thicken the damaged endometrium, increase the number of glands, promote endometrial angiogenesis, improve endometrial receptivity, and increase the rate of pregnancy in IUA rats.

Mechanistic insights into intrauterine adhesions

Intrauterine adhesions (IUA), also known as Asherman's syndrome, arise from damage to the basal layer of the endometrium, frequently caused by intrauterine interventions. This damage leads to nonregenerative healing of endometrium resulting in replacement by fibrous connective tissue, which bring about the adherence of opposing endometrium to render the uterine cavity and/or cervical canal partially or completely obliterated. IUA is a common cause of the refractory uterine infertility. Hysteroscopy is the gold standard for diagnosis of IUA. However, the method of accurately predicting the likelihood of achieving a live birth in the future remains established. Classical treatments have shown limited success, particularly in severe cases. Therefore, utilizing new research methods to deepen the understanding of the pathogenesis of IUA will facilitate the new treatment approaches to be found. In this article we briefly described the advances in the pathogenesis of IUA, with focus on inflammation and parenchymal cellular homeostasis disruption, defects in autophagy and the role of ferroptosis, and we also outlined the progress in IUA therapy.

Transcriptomics of tissue exosomes to investigate miR-195-5p's amelioration of endometrial fibrosis via the YAP-Smad7 pathway: an animal study

BACKGROUND

A significant research gap exists regarding the role of tissue exosomes in intrauterine adhesions (IUAs). This study aims to investigate the involvement of miR-195-5p and its regulatory network in IUAs through the analysis of tissue exosomes.

METHODS

Exosomes from rat uterine tissue with intrauterine adhesions were analyzed via transcriptomics to identify downstream target genes of miR-195-5p, cross-referencing with the human endometrial transcriptomics database GSE224093. Dual luciferase labeling confirmed miRNA-target gene interactions. The therapeutic efficacy of a miR-195-5p agonist was assessed in vivo through HE staining, Masson staining, and mating tests. The mechanisms underlying extracellular matrix (ECM) deposition and myofibroblast transdifferentiation in endometrial fibrosis were investigated both in vitro and in vivo using RT-PCR, Western Blot, immunofluorescence, and immunohistochemistry. Migration ability of endometrial stromal cells was evaluated using CCK8, scratch tests, and Transwell assays. Finally, the clinical potential of miR-195-5p was compared with autologous adipose-derived mesenchymal stem cells.

RESULTS

The expression of miR-195-5p in uterine tissue exosomes from intrauterine adhesions was found to be decreased. Treatment with a miR-195-5p agonist resulted in improved endometrial health, reduced fibrosis, increased glandular density, and enhanced birth rates in rats. Both in vivo and in vitro experiments confirmed that miR-195-5p decreased ECM deposition, reduced myofibroblast transdifferentiation, and inhibited the migration of endometrial stromal cells. This was achieved through the downregulation of YAP expression in the Hippo pathway and the upregulation of Smad7. Notably, the therapeutic efficacy of miR-195-5p agonists was comparable to that of stem cell therapy, offering promising avenues for clinical application.

CONCLUSIONS

Differential expression of miR-195-5p in tissue exosomes can reduce ECM deposition and myofibroblast transdifferentiation, improving endometrial fibrosis by regulating the YAP-Smad7 pathway in the Hippo signaling cascade.

Hydrogel Strategies for Female Reproduction Dysfunction

Infertility is an important issue for human reproductive health, with over half of all cases of infertility associated with female factors. Dysfunction of the complex female reproductive system may cause infertility. In clinical practice, female infertility is often treated with oral medications and/or surgical procedures, and ultimately with assisted reproductive technologies. Owing to their excellent biocompatibility, low immunogenicity, and adjustable mechanical properties, hydrogels are emerging as valuable tools in the reconstruction of organ function, supplemented by tissue engineering techniques to increase their structure and functionality. Hydrogel-based female reproductive reconstruction strategies targeting the pathological mechanisms of female infertility may provide alternatives for the treatment of ovarian, endometrium/uterine, and fallopian tube dysfunction. In this review, we provide a general introduction to the basic physiology and pathology of the female reproductive system, the limitations of current infertility treatments, and the lack of translation from animal models to human reproductive physiology. We further provide an overview of the current and future potential applications of hydrogels in the treatment of female reproductive system dysfunction, highlighting the great prospects of hydrogel-based strategies in the field of translational medicine, along with the significant challenges to be overcome.

Apelin-13 alleviates intrauterine adhesion by inhibiting epithelial-mesenchymal transition of endometrial epithelial cells and promoting angiogenesis

Intrauterine adhesion (IUA) is a common complication of surgical manipulation of the uterine cavity such as abortion. The pathology of IUA is characterized by fibrosis, but the pathogenesis is not fully understood. The function of Apelin-13 in IUA and related mechanisms were investigated in this study. The IUA rat model was established. The pathological changes and fibrosis degree of rat uterine tissues were detected by HE and Masson staining after intraperitoneal injection of Apelin-13. Epithelial-mesenchymal transition (EMT) of endometrial epithelial cells and endothelial-mesenchymal transition (EnMT) of vein endothelial cells were induced by TGF-β1. Tube-forming assay using HUVEC was implemented to detect the effect of Apelin-13 upon angiogenesis. IHC staining, immunofluorescence staining, and Western blot were conducted to detect the expression levels of EMT markers, angiogenesis, and key proteins of the TGF-β1/Smad signaling. Apelin-13 significantly alleviated IUA and fibrosis, and increased endometrial thickness and gland number in IUA rats. In addition, Apelin-13 significantly reversed EMT and EnMT induced by IUA modeling and TGF-β1, promoted the tube-forming ability of HUVEC, and up-regulated the expression of angiogenesis-related proteins. Mechanistically, Apelin-13 significantly suppressed smad2/3 phosphorylation and inhibited the TGF-β1/Smad signaling via its receptor APJ. Apelin-13 might alleviate IUA via repressing the TGF-β1/Smad pathway and is expected to be a potent therapeutic option for the clinical treatment of IUA.

Ultrasound-Responsive Hydrogel Incorporated with TGF-β Mimetic Peptides for Endometrium Recovery to Restore Fertility

Unavoidable damage to the basal layer of the endometrium has a huge negative impact on a woman's reproductive health and menstrual cycle. However, it is difficult for medicine to penetrate a series of biological barriers toward the basal layer in the deeper area of the endometrium. To meet this challenge, we developed an ultrasound-responsive hydrogel incorporated with a transforming growth factor-beta (TGF-β) mimetic peptide to enhance pregnancy outcomes by restoring the function of a wounded endometrium due to its deep-tissue-penetration capability. In vitro studies revealed that the TGF-β-mimetic-peptide-loaded hydrogel could achieve 64.35% of cell migration under ultrasound stimulation even in phosphate-buffered saline of pH 6.0. Upon in situ sonication at the uterus, carboxymethyl chitosan can be released from degraded hydrogel to open tight junctions with reduced interstitial pressure by ultrasound to promote deep penetration. Rat studies revealed that the penetration capability of TGF-β-mimetic-peptide-loaded hydrogel with sonication was 1.6 times higher than that of the control group. Besides the rat uterine model, ex vivo human uterine tissue was also collected and imaged, demonstrating up to ∼700 μm of tissue penetration depth. In addition, compared to control groups, effective uterus recovery without intrauterine stenosis and endometrial cavity fluid was observed from rats with severe uterine injury treated by TGF-β-mimetic-peptide-loaded hydrogel. In addition, fertility restoration in the endometrial injury model was observed after treatment with such an ultrasound-responsive hydrogel incorporated with TGF-β mimetic peptides. Overall, this work provides an effective approach to treating endometrial injury for enhanced pregnancy outcomes.

Current advances in understanding endometrial epithelial cell biology and therapeutic applications for intrauterine adhesion

The human endometrium is a highly regenerative tissue capable of undergoing scarless repair during the menstruation and postpartum phases. This process is mediated by endometrial adult stem/progenitor cells. During the healing of endometrial injuries, swift reepithelization results in the rapid covering of the wound surface and facilitates subsequent endometrial restoration. The involvement of endogenous endometrial epithelial stem cells, stromal cells, and bone marrow-derived cells in the regeneration of the endometrial epithelium has been a subject of prolonged debate. Increasing evidence suggests that the regeneration of the endometrial epithelium mainly relies on epithelial stem cells rather than stromal cells and bone marrow-derived cells. Currently, no consensus has been established on the identity of epithelial stem cells in the epithelial compartment. Several markers, including stage-specific embryonic antigen-1 (SSEA-1), sex-determining region Y-box 9 (SOX9), neural-cadherin (N-cadherin), leucine-rich-repeat-containing G-protein-coupled receptor 5 (LGR5), CD44, axis inhibition protein 2 (Axin2), and aldehyde dehydrogenase 1A1 (ALDH1A1), have been suggested as potential candidate markers for endometrial epithelial stem cells. The identification of endometrial epithelial stem cells contributes to our understanding of endometrial regeneration and offers new therapeutic insights into diseases characterized by regenerative defects in the endometrium, such as intrauterine adhesion. This review explores different perspectives on the origins of human and mouse endometrial epithelial cells. It summarizes the potential markers, locations, and hierarchies of epithelial stem cells in both human and mouse endometrium. It also discusses epithelial cell-based treatments for intrauterine adhesion, hoping to inspire further research and clinical application of endometrial epithelial stem cells.

Biomimicking trilayer scaffolds with controlled estradiol release for uterine tissue regeneration

Scaffold-based tissue engineering provides an efficient approach for repairing uterine tissue defects and restoring fertility. In the current study, a novel trilayer tissue engineering scaffold with high similarity to the uterine tissue in structure was designed and fabricated via 4D printing, electrospinning and 3D bioprinting for uterine regeneration. Highly stretchable poly(l-lactide-co-trimethylene carbonate) (PLLA-co-TMC, "PTMC" in short)/thermoplastic polyurethane (TPU) polymer blend scaffolds were firstly made via 4D printing. To improve the biocompatibility, porous poly(lactic acid-co-glycolic acid) (PLGA)/gelatin methacryloyl (GelMA) fibers incorporated with polydopamine (PDA) particles were produced on PTMC/TPU scaffolds via electrospinning. Importantly, estradiol (E2) was encapsulated in PDA particles. The bilayer scaffolds thus produced could provide controlled and sustained release of E2. Subsequently, bone marrow derived mesenchymal stem cells (BMSCs) were mixed with gelatin methacryloyl (GelMA)-based inks and the formulated bioinks were used to fabricate a cell-laden hydrogel layer on the bilayer scaffolds via 3D bioprinting, forming ultimately biomimicking trilayer scaffolds for uterine tissue regeneration. The trilayer tissue engineering scaffolds thus formed exhibited a shape morphing ability by transforming from the planar shape to tubular structures when immersed in the culture medium at 37°C. The trilayer tissue engineering scaffolds under development would provide new insights for uterine tissue regeneration.

Droplet Microfluidics Powered Hydrogel Microparticles for Stem Cell-Mediated Biomedical Applications

Stem cell-related therapeutic technologies have garnered significant attention of the research community for their multi-faceted applications. To promote the therapeutic effects of stem cells, the strategies for cell microencapsulation in hydrogel microparticles have been widely explored, as the hydrogel microparticles have the potential to facilitate oxygen diffusion and nutrient transport alongside their ability to promote crucial cell-cell and cell-matrix interactions. Despite their significant promise, there is an acute shortage of automated, standardized, and reproducible platforms to further stem cell-related research. Microfluidics offers an intriguing platform to produce stem cell-laden hydrogel microparticles (SCHMs) owing to its ability to manipulate the fluids at the micrometer scale as well as precisely control the structure and composition of microparticles. In this review, the typical biomaterials and crosslinking methods for microfluidic encapsulation of stem cells as well as the progress in droplet-based microfluidics for the fabrication of SCHMs are outlined. Moreover, the important biomedical applications of SCHMs are highlighted, including regenerative medicine, tissue engineering, scale-up production of stem cells, and microenvironmental simulation for fundamental cell studies. Overall, microfluidics holds tremendous potential for enabling the production of diverse hydrogel microparticles and is worthy for various stem cell-related biomedical applications.

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

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

miR-340-3p-modified bone marrow mesenchymal stem cell-derived exosomes inhibit ferroptosis through METTL3-mediated m6A modification of HMOX1 to promote recovery of injured rat uterus

BACKGROUND

Ferroptosis is associated with the pathological progression of hemorrhagic injury and ischemia-reperfusion injury. According to our previous study, exosomes formed through bone marrow mesenchymal stem cells modified with miR-340-3p (MB-exos) can restore damaged endometrium. However, the involvement of ferroptosis in endometrial injury and the effect of MB-exos on ferroptosis remain elusive.

METHODS

The endometrial injury rat model was developed. Exosomes were obtained from the supernatants of bone marrow mesenchymal stromal cells (BMSCs) and miR-340/BMSCs through differential centrifugation. We conducted RNA-seq analysis on endometrial tissues obtained from the PBS and MB-exos groups. Ferroptosis was induced in endometrial stromal cells (ESCs) by treating them with erastin or RSL3, followed by treatment with B-exos or MB-exos. We assessed the endometrial total m6A modification level after injury and subsequent treatment with B-exos or MB-exos by methylation quantification assay. We performed meRIP-qPCR to analyze m6A modification-regulated endogenous mRNAs.

RESULTS

We reveal that MB-exos facilitate the injured endometrium to recover by suppressing ferroptosis in endometrial stromal cells. The injured endometrium showed significantly upregulated N6-methyladenosine (m6A) modification levels; these levels were attenuated by MB-exos through downregulation of the methylase METTL3. Intriguingly, METTL3 downregulation appears to repress ferroptosis by stabilizing HMOX1 mRNA, thereby potentially elucidating the mechanism through which MB-exos inhibit ferroptosis in ESCs. We identified YTHDF2 as a critical m6A reader protein that contributes to HMOX1 mRNA degradation. YTHDF2 facilitates HMOX1 mRNA degradation by identifying the m6A binding site in the 3'-untranslated regions of HMOX1. In a rat model, treatment with MB-exos ameliorated endometrial injury-induced fibrosis by inhibiting ferroptosis in ESCs. Moreover, METTL3 short hairpin RNA-mediated inhibition of m6A modification enhanced the inhibitory effect of MB-exos on ferroptosis in endometrial injury.

CONCLUSIONS

Thus, these observations provide new insights regarding the molecular mechanisms responsible for endometrial recovery promotion by MB-exos and highlight m6A modification-dependent ferroptosis inhibition as a prospective therapeutic target to attenuate endometrial injury.

Biomaterial Fg/P(LLA-CL) regulates macrophage polarization and recruitment of mesenchymal stem cells after endometrial injury

The process of endometrial repair after injury involves the synergistic action of various cells including immune cells and stem cells. In this study, after combing Fibrinogen(Fg) with poly(L-lacticacid)-co-poly(ε-caprolactone)(P(LLA-CL)) by electrospinning, we placed Fg/P(LLA-CL) into the uterine cavity of endometrium-injured rats, and bioinformatic analysis revealed that Fg/P(LLA-CL) may affect inflammatory response and stem cell biological behavior. Therefore, we verified that Fg/P(LLA-CL) could inhibit the lipopolysaccharide (LPS)-stimulated macrophages from switching to the pro-inflammatory M1 phenotype in vitro. Moreover, in the rat model of endometrial injury, Fg/P(LLA-CL) effectively promoted the polarization of macrophages towards the anti-inflammatory M2 phenotype and enhanced the presence of mesenchymal stem cells at the injury site. Overall, Fg/P(LLA-CL) exhibits significant influence on macrophage polarization and stem cell behavior in endometrial injury, justifying further exploration for potential therapeutic applications in endometrial and other tissue injuries.

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

OBJECTIVE

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

METHODS

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

RESULTS

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

CONCLUSION

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

Restoration of functional endometrium in an intrauterine adhesion rat model with endometrial stromal cells transplantation

BACKGROUND

Intrauterine adhesion (IUA) as a prevalent gynecological disease is developed from infection or trauma. However, therapeutic strategies to repair damaged endometrium are relatively limited. Emerging studies have shed light on the crucial role of endometrial stromal cells (EnSCs) in the process of uterine endometrial regeneration. EnSCs isolated from the uterine endometrium have similar characteristics to mesenchymal stem cells (MSCs). However, it is still unknown whether EnSCs could be used as donor cells to treat IUA. The aim of this study was to evaluate the potential efficacy of EnSCs in treating rat IUA.

METHODS

Human EnSCs were isolated from the endometrial tissue of healthy female donors and subjected to extensive expansion and culture in vitro. Immunofluorescence, flow cytometry, cell proliferation assay, trilineage differentiation experiment, and decidualization assay were used to characterize the biological properties of EnSCs. We evaluated the immunoregulatory potential of EnSCs by analyzing their secreted cytokines and conducting bulk RNA sequencing after IFN-γ treatment. After EnSCs were transplanted into the uterine muscle layer in IUA rats, their therapeutic effects and underlying mechanisms were analyzed using histological analysis, Q-PCR, fertility and pregnancy outcome assay, and transcriptome analysis.

RESULTS

We successfully isolated EnSCs from the endometrium of human donors and largely expanded in vitro. EnSCs exhibited characteristics of mesenchymal stem cells and retained responsiveness to sex hormones. Following IFN-γ stimulation, EnSCs upregulated the anti-inflammatory cytokines and activated immunosuppressive molecules. Xenogeneic transplantation of EnSCs successfully repaired injured endometrium and significantly restored the pregnancy rate in IUA rats. Mechanistically, the therapeutic effects of EnSCs on IUA endometrium functioned through anti-inflammation, anti-fibrosis and the secretion of regeneration factor.

CONCLUSIONS

Due to their large expansion ability, immunoregulatory properties, and great potential in treating IUA, EnSCs, as a valuable source of donor cells, could offer a potential treatment avenue for injury-induced IUA.

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.

Bio-distribution and toxicity potential of human umbilical cord mesenchymal stem cells in cynomolgus monkeys

Mesenchymal stem cells (MSCs) have demonstrated promising advantages in the therapies of many diseases, while its multi-directional differentiation potential and immunotoxicity are the major concerns hindered their clinical translation. In this study, human umbilical Mesenchymal stem cell (hUC-MSCs) were labeled with a near-infrared fluorescent dye DiR before infused into cynomolgus monkeys, and the amount of hUC-MSCs in the peripheral blood were dynamically estimated from 5 min to 28 days post a single administration at 3 × 106 cells/kg and 2 × 107 cells/kg intravenously. As results, some hUC-MSCs distributed to the whole body within 5 min, while most of the cells accumulate in the lungs along with the systemic blood circulation, and subsequently released into the blood. The toxicity potentials of hUC-MSCs were investigated in another 30 cynomolgus monkeys, and the cells were repeatedly administrated at doses of 3 × 106 cells/kg and 2 × 107 cells/kg for 5 times on a weekly basis, with a recovery period of 1 months. hUC-MSCs showed no obvious toxic effects in cynomolgus monkeys, except xenogeneic immune rejection to human stem cells. Low levels of the hUC-MSC gene were detected in the peripheral blood of a few animals administered 2 × 107 cells/kg at 30 min subsequent to the first and last administration, and there was no significant difference in the copy number of the hUC-MSC gene in the blood samples compared with the first and last administration, indicating that the hUC-MSC was not significantly amplified in vivo, and it its safe in non-human primates. Our study for the first time verified the safety of long-term use of hUC-MSCs in primates. We have pioneered a technology for the real-time detection of hUC-MSCs in peripheral blood and provide dynamicand rapid monitoring of the distribution characteristics of hUC-MSCs in vivo. Here, we provide data supporting the application of such products for clinical treatment and the application of stem cells in major refractory diseases and regenerative medicine.

Histological study of telocytes in mice intrauterine adhesion model and their positive effect on mesenchymal stem cells in vitro

Intrauterine adhesions (IUA), the main cause of secondary infertility in women, result from irreversible fibrotic repair of the endometrium due to inflammation or human factors, accompanied by disruptions in the repair function of endometrial stem cells. This significantly impacts the physical and mental health of women in their childbearing years. Telocytes (TCs), a distinctive type of interstitial cells found in various tissues and organs, play diverse repair functions due to their unique spatial structure. In this study, we conduct the inaugural exploration of the changes in TCs in IUA disease and their potential impact on the function of stem cells. Our results show that in vivo, through double immunofluorescence staining (CD34+/Vimentin+; CD34+/CD31-), as endometrial fibrosis deepens, the number of TCs gradually decreases, telopodes shorten, and the three-dimensional structure becomes disrupted in the mouse IUA mode. In vitro, TCs can promote the proliferation and cycle of bone mesenchymal stem cells (BMSCs) by promoting the Wnt/β-catenin signaling pathway, which were inhibited using XAV939. TCs can promote the migrated ability of BMSCs and contribute to the repair of stem cells during endometrial injury. In addition, TCs can inhibit the apoptosis of BMSCs through the Bcl-2/Bax pathway. In conclusion, our study demonstrates, for the first time, the resistance role of TCs in IUA disease, shedding light on their potential involvement in endometrial repair through the modulation of stem cell function.

Injectable "Homing-Like" Bioactive Short-Fibers for Endometrial Repair and Efficient Live Births

The prevalence of infertility caused by endometrial defects is steadily increasing, posing a significant challenge to women's reproductive health. In this study, injectable "homing-like" bioactive decellularized extracellular matrix short-fibers (DEFs) of porcine skin origin are innovatively designed for endometrial and fertility restoration. The DEFs can effectively bind to endometrial cells through noncovalent dipole interactions and release bioactive growth factors in situ. In vitro, the DEFs effectively attracted endometrial cells through the "homing-like" effect, enabling cell adhesion, spreading, and proliferation on their surface. Furthermore, the DEFs effectively facilitated the proliferation and angiogenesis of human primary endometrial stromal cells (HESCs) and human umbilical vein endothelial cells (HUVECs), and inhibited fibrosis of pretreated HESCs. In vivo, the DEFs significantly accelerated endometrial restoration, angiogenesis, and receptivity. Notably, the deposition of endometrial collagen decreased from 41.19 ± 2.16% to 14.15 ± 1.70% with DEFs treatment. Most importantly, in endometrium-injured rats, the use of DEFs increased the live birth rate from 30% to an impressive 90%, and the number and development of live births close to normal rats. The injectable "homing-like" bioactive DEFs system can achieve efficient live births and intrauterine injection of DEFs provides a new promising clinical strategy for endometrial factor infertility.

Umbilical cord mesenchymal stem cell-derived exosomes inhibits fibrosis in human endometrial stromal cells via miR-140-3p/FOXP1/Smad axis

Endometrial fibrosis is the histologic appearance of intrauterine adhesion (IUA). Emerging evidences demonstrated umbilical cord mesenchymal stem cell-derived exosomes (UCMSC-exo) could alleviate endometrial fibrosis. But the specific mechanism is not clear. In this study, we explored the effect of UCMSC-exo on endometrial fibrosis, and investigated the possible role of miR-140-3p/FOXP1/Smad axis in anti-fibrotic properties of UCMSC-exo. UCMSC-exo were isolated and identified. Transforming growth factor-β (TGF-β) was used to induce human endometrial stromal cell (HESC) fibrosis. Dual luciferase assay was performed to verify the relationship between miR-140-3p and FOXP1. The expressions of fibrotic markers, SIP1, and p-Smad2/p-Smad3 in HESCs stimulated with UCMSC-exo were detected by western blot. In addition, the effects of miR-140-3p mimic, miR-140-3p inhibitor and FOXP1 over-expression on endometrial fibrosis were assessed. The isolated UCMSC-exo had a typical cup-shaped morphology and could be internalized into HESCs. The expressions of fibrotic markers were significantly increased by TGF-β, which was reversed by UCMSC-exo. MiR-140-3p in UCMSC-exo ameliorated TGf-β-induced HESCs fibrosis. FOXP1 was identified as the direct target of miR-140-3p, which could inversely regulate miR-140-3p's function on HESCs fibrosis. Furthermore, we demonstrated that miR-140-3p in UCMSC-exo regulated Smad signal pathway to exert the anti-fibrotic effect in HESCs. The anti-fibrotic effect of UCMSC-derived exosomes against HESC fibrosis was at least partially achieved by miR-140-3p/FOXP1/Smad axis.

Human umbilical cord-derived mesenchymal stem cells and auto-crosslinked hyaluronic acid gel complex for treatment of intrauterine adhesion

OBJECTIVE

The purpose of this study was to explore the therapeutic characteristics of mesenchymal stem cells generated from human umbilical cord (hUC-MSCs) when utilized in conjunction with auto-crosslinked hyaluronic acid gel (HA-gel) for the management of intrauterine adhesion (IUA). The goal was to see how this novel therapy could enhance healing and improve outcomes for IUA patients.

METHODS

In this study, models of intrauterine adhesion (IUA) were established in Sprague-Dawley (SD) rats, which were then organized and divided into hUC-MSCs groups. The groups involved: hUC-MSCs/HA-gel group, control group, and HA-gel group. Following treatment, the researchers examined the uterine cavities and performed detailed analyses of the endometrial tissues to determine the effectiveness of the interventions.

RESULTS

The results indicated that in comparison with to the control group, both HA-gel, hUC-MSCs, and hUC-MSCs/HA-gel groups showed partial repair of IUA. However, in a more notable fashion transplantation of hUC-MSCs/HA-gel complex demonstrated significant dual repair effects. Significant outcomes were observed in the group treated with hUC-MSCs and HA-gel, they showed thicker endometrial layers, less fibrotic tissue, and a higher number of endometrial glands. This treatment strategy also resulted in a significant improvement in fertility restoration, indicating a profound therapeutic effect.

CONCLUSIONS

The findings of this study suggest that both HA-gel, hUC-MSCs, and hUC-MSCs/HA-gel complexes have the potential for partial repair of IUA and fertility restoration caused by endometrium mechanical injury. Nonetheless, the transplantation of the hUC-MSCs/HA-gel complex displayed exceptional dual healing effects, combining effective anti-adhesive properties with endometrial regeneration stimuli.

Minimally invasive delivery of human umbilical cord-derived mesenchymal stem cells by an injectable hydrogel via Diels-Alder click reaction for the treatment of intrauterine adhesions

Intrauterine adhesions (IUA) are the most common cause of uterine infertility, and conventional treatments have not consistently achieved satisfactory pregnancy rates. Stem cell therapy shows promising potential for the clinical treatment of IUA. Although various advanced biomaterials have been designed for delivering stem cells to the uterine cavity, there remain significant challenges, particularly in devising therapeutic strategies for clinical application that minimize surgical incisions and conform to the intricate structure of uterine cavity. Herein, an injectable hydrogel loaded with human umbilical cord-derived mesenchymal stem cells (UCMSCs) was synthesized via the Diels-Alder click reaction for endometrial regeneration and fertility restoration, exhibiting suitable mechanical properties, good biocompatibility, and desirable degradation properties. Notably, this hydrogel permitted minimally invasive administration and integrated seamlessly with surrounding tissue. Our study revealed that the UCMSCs-laden injectable hydrogel enhanced cell proliferation, migration, angiogenesis, and exhibited anti-fibrotic effects in vitro. The implantation of this hydrogel significantly facilitated endometrium regeneration and restored fertility in a rat endometrial damage model. Mechanistically, in vivo results indicated that the UCMSCs-laden injectable hydrogel effectively promoted macrophage recruitment and facilitated M2 phenotype polarization. Collectively, this hydrogel demonstrated efficacy in regenerating damaged endometrium, leading to the restoration of fertility. Consequently, it holds promise as a potential therapeutic strategy for endometrial damage and fertility decline arising from intrauterine adhesions. STATEMENT OF SIGNIFICANCE: Severe endometrial traumas frequently lead to intrauterine adhesions and subsequent infertility. Stem cell therapy shows promising potential for the clinical treatment of IUA; however, challenges remain, including low delivery efficiency and compromised stem cell activity during the delivery process. In this study, we fabricated an injectable hydrogel loaded with UCMSCs via the Diels-Alder click reaction, which exhibited unique bioorthogonality. The in situ-gelling hydrogels could be introduced through a minimally invasive procedure and adapt to the intricate anatomy of the uterus. The UCMSCs-laden injectable hydrogel promoted endometrial regeneration and fertility restoration in a rat endometrial damage model, efficaciously augmenting macrophage recruitment and promoting their polarization to the M2 phenotype. The administration of UCMSCs-laden injectable hydrogel presents a promising therapeutic strategy for patients with severe intrauterine adhesion.

Hypoxic bone marrow mesenchymal stem cell exosomes promote angiogenesis and enhance endometrial injury repair through the miR-424-5p-mediated DLL4/Notch signaling pathway

Background

Currently, bone marrow mesenchymal stem cells (BMSCs) have been reported to promote endometrial regeneration in rat models of mechanically injury-induced uterine adhesions (IUAs), but the therapeutic effects and mechanisms of hypoxic BMSC-derived exosomes on IUAs have not been elucidated.

Objective

To investigate the potential mechanism by which the BMSCS-derived exosomal miR-424-5p regulates IUA angiogenesis through the DLL4/Notch signaling pathway under hypoxic conditions and promotes endometrial injury repair.

Methods

The morphology of the exosomes was observed via transmission electron microscopy, and the expression of exosome markers (CD9, CD63, CD81, and HSP70) was detected via flow cytometry and Western blotting. The expression of angiogenesis-related genes (Ang1, Flk1, Vash1, and TSP1) was detected via RT‒qPCR, and the expression of DLL4/Notch signaling pathway-related proteins (DLL4, Notch1, and Notch2) was detected via Western blotting. Cell proliferation was detected by a CCK-8 assay, and angiogenesis was assessed via an angiogenesis assay. The expression of CD3 was detected by immunofluorescence. The endometrial lesions of IUA rats were observed via HE staining, and the expression of CD3 and VEGFA was detected via immunohistochemistry.

Results

Compared with those in exosomes from normoxic conditions, miR-424-5p was more highly expressed in the exosomes from hypoxic BMSCs. Compared with those in normoxic BMSC-derived exosomes, the proliferation and angiogenesis of HUVECs were significantly enhanced after treatment with hypoxic BMSC-derived exosomes, and these effects were weakened after inhibition of miR-424-5p. miR-424-5p can target and negatively regulate the expression of DLL4, promote the expression of the proangiogenic genes Ang1 and Flk1, and inhibit the expression of the antiangiogenic genes Vash1 and TSP1. The effect of miR-424-5p can be reversed by overexpression of DLL4. In IUA rats, treatment with hypoxic BMSC exosomes and the miR-424-5p mimic promoted angiogenesis and improved endometrial damage.

Conclusion

The hypoxic BMSC-derived exosomal miR-424-5p promoted angiogenesis and improved endometrial injury repair by regulating the DLL4/Notch signaling pathway, which provides a new idea for the treatment of IUAs.

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.

Establishment and comparison of different procedures for modeling intrauterine adhesion in rats: A preliminary study

The establishment of a stable animal model for intrauterine adhesion (IUA) can significantly enhance research on the pathogenesis and pathological changes of this disease, as well as on the development of innovative therapeutic approaches. In this study, three different modeling methods, including phenol mucilage combined mechanical scraping, ethanol combined mechanical scraping and ethanol modeling alone were designed. The morphological characteristics of the models were evaluated. The underlying mechanisms and fertility capacity of the ethanol modeling group were analyzed and compared to those of the sham surgery group. All three methods resulted in severe intrauterine adhesions, with ethanol being identified as a reliable modeling agent and was subsequently subjected to further evaluation. Immunohistochemistry and RT-PCR results indicated that the ethanol modeling group exhibited an increase in the degree of fibrosis and inflammation, as well as a significant reduction in endometrial thickness, gland number, vascularization, and endometrial receptivity, ultimately resulting in the loss of fertility capacity. The aforementioned findings indicate that the intrauterine perfusion of 95 % ethanol is efficacious in inducing the development of intrauterine adhesions in rats. Given its cost-effectiveness, efficacy, and stability in IUA formation, the use of 95 % ethanol intrauterine perfusion may serve as a novel platform for evaluating innovative anti-adhesion materials and bioengineered therapies.

Long noncoding RNAs regulate intrauterine adhesion and cervical cancer development and progression

Intrauterine adhesion, one of reproductive system diseases in females, is developed due to endometrial injury, such as infection, trauma, uterine congenital abnormalities and uterine curettage. Intrauterine adhesion affects female infertility and causes several complications, including amenorrhoea, hypomenorrhoea, and recurrent abortion. Cervical cancer is one of the common gynecological tumors and the fourth leading cancer-related death in women worldwide. Although the treatments of cervical cancer have been improved, the advanced cervical cancer patients have a low survival rate due to tumor recurrence and metastasis. The molecular mechanisms of intrauterine adhesion and cervical tumorigenesis have not been fully elucidated. In recent years, long noncoding RNAs (lncRNAs) have been known to participate in intrauterine adhesion and cervical carcinogenesis. Therefore, in this review, we will summarize the role of lncRNAs in regulation of intrauterine adhesion development and progression. Moreover, we will discuss the several lncRNAs in control of cervical oncogenesis and progression. Furthermore, we highlight that targeting lncRNAs could be used for treatment of intrauterine adhesion and cervical cancer.

Endometrial mesenchymal stromal/stem cells improve regeneration of injured endometrium in mice

BACKGROUND

The monthly regeneration of human endometrial tissue is maintained by the presence of human endometrial mesenchymal stromal/stem cells (eMSC), a cell population co-expressing the perivascular markers CD140b and CD146. Endometrial regeneration is impaired in the presence of intrauterine adhesions, leading to infertility, recurrent pregnancy loss and placental abnormalities. Several types of somatic stem cells have been used to repair the damaged endometrium in animal models, reporting successful pregnancy. However, the ability of endometrial stem cells to repair the damaged endometrium remains unknown.

METHODS

Electrocoagulation was applied to the left uterine horn of NOD/SCID mice causing endometrial injury. Human eMSC or PBS was then injected into the left injured horn while the right normal horn served as controls. Mice were sacrificed at different timepoints (Day 3, 7 and 14) and the endometrial morphological changes as well as the degree of endometrial injury and repair were observed by histological staining. Gene expression of various inflammatory markers was assessed using qPCR. The functionality of the repaired endometrium was evaluated by fertility test.

RESULTS

Human eMSC successfully incorporated into the injured uterine horn, which displayed significant morphological restoration. Also, endometrium in the eMSC group showed better cell proliferation and glands formation than the PBS group. Although the number of blood vessels were similar between the two groups, gene expression of VEGF-α significantly increased in the eMSC group. Moreover, eMSC had a positive impact on the regeneration of both stromal and epithelial components of the mouse endometrium, indicated by significantly higher vimentin and CK19 protein expression. Reduced endometrial fibrosis and down-regulation of fibrosis markers were also observed in the eMSC group. The eMSC group had a significantly higher gene expression of anti-inflammatory factor Il-10 and lower mRNA level of pro-inflammatory factors Ifng and Il-2, indicating the role of eMSC in regulation of inflammatory reactions. The eMSC group showed higher implantation sites than the PBS group, suggesting better endometrial receptivity with the presence of newly emerged endometrial lining.

CONCLUSIONS

Our findings suggest eMSC improves regeneration of injured endometrium in mice.

Endometrium procurement and transplantation restores fertility in rats

RESEARCH QUESTION

Can rat endometrium be successfully procured and transplanted, and can a similar method be used to procure human endometrium?

DESIGN

Rat endometrium was procured using an endometrium stripping method and transplanted into female Sprague-Dawley rats. Macroscopic and histological changes, endometrial receptivity-related protein concentrations and fertility were assessed. Additionally, a preliminary experiment was conducted to procure human endometrium using a similar method.

RESULTS

Endometrium was successfully procured from both rats and humans, which contained intact endometrium and parts of the adjacent inner annulus myometrium. Endometrium auto-transplantation was conducted in rats and the procedure lasted a total of 41.3 ± 5.7 min with a mean blood loss of 0.09 ± 0.04 g. The transplanted endometrium survived well, but a fibrotic zone formed between the transplant and recipient tissue. Compared with sham rats, those with endometrium transplantation had similar endometrial thickness and endometrial gland numbers but reduced vascular density at 8 weeks after surgery. Endometrium transplantation also retained expression of the endometrial receptivity-related proteins leukaemia inhibitory factor and vascular endothelial growth factor. In contrast to non-pregnancy in the stripped horn, a mean of 5.0 ± 2.7 fetuses developed in the transplanted horn, and full-term live fetuses were conceived in the horns with transplanted endometrium.

CONCLUSIONS

Endometrium procurement by stripping method can obtain an intact and functional endometrium, and endometrium transplantation can reconstruct the uterine cavity and restore fertility in rats.

Study on the Mechanism of Estrogen Regulating Endometrial Fibrosis After Mechanical Injury Via MIR-21-5P/PPARΑ/FAO Axis

BACKGROUND

Intrauterine adhesion (IUA) caused by endometrial mechanical injury has been found as a substantial risk factor for female infertility (e.g., induced abortion). Estrogen is a classic drug for the repair of endometrial injury, but its action mechanism in the clinical application of endometrial fibrosis is still unclear.

OBJECTIVE

To explore the specific action mechanism of estrogen treatment on IUA.

METHODS

The IUA model in vivo and the isolated endometrial stromal cells (ESCs) model in vitro were built. Then CCK8 assay, Real-Time PCR, Western Blot and Dual- Luciferase Reporter Gene assay were applied to determine the targeting action of estrogen on ESCs.

RESULTS

It was found that 17β-estradiol inhibited fibrosis of ESCs by down-regulating miR-21-5p level and activating PPARα signaling. Mechanistically, miR-21-5p significantly reduced the inhibitory effect of 17β-estradiol on fibrotic ESCs (ESCs-F) and its maker protein (e.g., α-SMA, collagen I, and fibronectin), where targeting to PPARα 3'- UTR and blocked its activation and transcription, thus lowering expressions of fatty acid oxidation (FAO) associated key enzyme, provoking fatty accumulation and reactive oxygen species (ROS) production, resulting in endometrial fibrosis. Nevertheless, the PPARα agonist caffeic acid counteracted the facilitation action of miR-21-5p on ESCs-F, which is consistent with the efficacy of estrogen intervention.

CONCLUSION

In brief, the above findings revealed that the miR-21-5p/PPARα signal axis played an important role in the fibrosis of endometrial mechanical injury and suggested that estrogen might be a promising agent for its progression.

Effects of treatment with stem cell-derived extracellular vesicles in preclinical rodent models of intrauterine adhesion: A meta-analysis

Background

Intrauterine adhesion (IUA) results from serious complications of intrauterine surgery or infection and mostly remains incurable. Small extracellular vesicles (sEVs) derived from mesenchymal stem cells (MSCs) have emerged as a potential new approach for the treatment of IUA; however, their impact is not fully understood. Here, we performed a meta-analysis summarizing the effects of sEVs on IUA in preclinical rodent models.

Methods

This meta-analysis included searches of PubMed, EMBASE, Cochrane, and the Web of Science databases from January 1, 1997, to April 1, 2022, to identify studies reporting the therapeutic effect of sEVs on rodent preclinical animal models of IUA. We compared improvements in endometrial thickness, endometrial gland number, fibrosis area, embryo number, vascular endothelial growth factor (VEGF), transforming growth factor β1 (TGFβ1), and leukemia inhibitory factor (LIF) levels after treatment.

Results

Our search included 100 citations, of which 7 met the inclusion criteria, representing 231 animals. Compared with that in the control group, the fibrosis area in the sEV-treated group was significantly reduced (standardized mean difference (SMD) = -6.87，95 % confidence interval (CI) = -9.67 to -4.07). The number of glands increased after the intervention (95 % CI, 3.72-7.68; P = 0.000). Endometrial thickness was significantly improved in the sEV-treated group (SMD = 2.57, 95 % CI, 1.62-3.52).

Conclusions

This meta-analysis is highlighting that sEV treatment can improve the area of endometrial fibrosis, as well as VEGF, and LIF level, in a mouse IUA model. This knowledge of these findings will provide new insights into future preclinical research.

Quantification of Endometrial Fibrosis Using Noninvasive MRI T2 Mapping: Initial Findings

BACKGROUND

Endometrial fibrosis may cause infertility. Accurate evaluation of endometrial fibrosis helps clinicians to schedule timely therapy.

PURPOSE

To explore T2 mapping for assessing endometrial fibrosis.

STUDY TYPE

Prospective.

POPULATION

Ninety-seven women with severe endometrial fibrosis (SEF) and 21 patients with mild to moderate endometrial fibrosis (MMEF), diagnosed by hysteroscopy, and 37 healthy women.

FIELD STRENGTH/SEQUENCE

3T, T2-weighted turbo spin echo (T2-weighted imaging) and multi-echo turbo spin echo (T2 mapping) sequences.

ASSESSMENT

Endometrial MRI parameters (T2, thickness [ET], area [EA], and volume [EV]) were measured by N.Z. and Q.H. (9- and 4-years' experience in pelvic MRI) and compared between the three subgroups. A multivariable model including MRI parameters and clinical variables (including age and body mass index [BMI]) was developed to predict endometrial fibrosis assessed by hysteroscopy.

STATISTICAL TESTS

Kruskal-Wallis; ANOVA; Spearman's correlation coefficient (rho); area under the receiver operating characteristic curve (AUC); binary logistic regression; intraclass correlation coefficient (ICC). P value <0.05 for statistical significance.

RESULTS

Endometrial T2, ET, EA, and EV of MMEF patients (185 msec, 8.2 mm, 168 mm2 , and 2181 mm3 ) and SEF patients (164 msec, 6.7 mm, 120 mm2 , and 1762 mm3 ) were significantly lower than those of healthy women (222 msec, 11.7 mm, 316 mm2 , and 3960 mm3 ). Endometrial T2 and ET of SEF patients were significantly lower than those of MMEF patients. Endometrial T2, ET, EA, and EV were significantly correlated to the degree of endometrial fibrosis (rho = -0.623, -0.695, -0.694, -0.595). There were significant strong correlations between ET, EA, and EV in healthy women and MMEF patients (rho = 0.850-0.908). Endometrial MRI parameters and the multivariable model accurately distinguished MMEF or SEF from normal endometrium (AUCs >0.800). Age, BMI, and MRI parameters in univariable analysis and age and T2 in multivariable analysis significantly predicted endometrial fibrosis. The reproducibility of MRI parameters was excellent (ICC, 0.859-0.980).

DATA CONCLUSION

T2 mapping has potential to noninvasively and quantitatively evaluate the degree of endometrial fibrosis.

EVIDENCE LEVEL

2 Technical Efficacy: Stage 2.

Novel therapeutic strategies for injured endometrium: intrauterine transplantation of menstrual blood‑derived cells from infertile patients

BACKGROUND

Menstrual blood-derived cells show regenerative potential as a mesenchymal stem cell and may therefore be a novel stem cell source of treatment for refractory infertility with injured endometrium. However, there have been few pre-clinical studies using cells from infertile patients, which need to be addressed before establishing an autologous transplantation. Herein, we aimed to investigate the therapeutic capacity of menstrual blood-derived cells from infertile patients on endometrial infertility.

METHODS

We collected menstrual blood-derived cells from volunteers and infertile patients and confirmed their mesenchymal stem cell phenotype by flow cytometry and induction of tri-lineage differentiation. We compared the proliferative and paracrine capacities of these cells. Furthermore, we also investigated the regenerative potential and safety concerns of the intrauterine transplantation of infertile patient-derived cells using a mouse model with mechanically injured endometrium.

RESULTS

Menstrual blood-derived cells from both infertile patients and volunteers showed phenotypic characteristics of mesenchymal stem cells. In vitro proliferative and paracrine capacities for wound healing and angiogenesis were equal for both samples. Furthermore, the transplantation of infertile patient-derived cells into uterine horns of the mouse model ameliorated endometrial thickness, prevented fibrosis, and improved fertility outcomes without any apparent complications.

CONCLUSIONS

In our pre-clinical study, intrauterine transplantation of menstrual blood-derived cells may be a novel and attractive stem cell source for the curative and prophylactic therapy for injured endometrium. Further studies will be warranted for future clinical application.

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.

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.

Effect of stem cell conditional medium-loading adhesive hydrogel on TGF-β1-induced endometrial stromal cell fibrosis

Introduction: Uterine adhesion (IUA) is a severe complication that results from uterine operations or uterine infections. Hysteroscopy is considered the gold standard for the diagnosis and treatment of uterine adhesions. Yet, this invasive procedure leads to re-adhesions after hysteroscopic treatment. Hydrogels loading functional additives (e.g., placental mesenchymal stem cells (PC-MSCs)) that can act as physical barriers and promote endometrium regeneration are a good solution. However, traditional hydrogels lack tissue adhesion which makes them unstable under a rapid turnover of the uterus, and PC-MSCs have biosafety risks when used as functional additives. Methods: In this study, we coupled an adhesive hydrogel with a PC-MSCs conditioned medium (CM) to form a hybrid of gel and functional additives (CM/Gel-MA). Results and Discussion: Our experiments show that CM/Gel-MA enhances the activity of endometrial stromal cells (ESCs), promotes cell proliferation, and reduces the expression of α-SMA, collagen I, CTGF, E-cadherin, and IL-6, which helps to reduce the inflammatory response and inhibit fibrosis. We conclude that CM/Gel-MA can more potentially prevent IUA by combining the physical barriers from adhesive hydrogel and functional promotion from CM.