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

The KSR1/MEK/ERK signaling pathway promotes the progression of intrauterine adhesions

Kinase suppressor of Ras 1 (KSR1) serves as a scaffold protein within the RAS-RAF pathway and plays a role in tumorigenesis, immune regulation, cell proliferation, and apoptosis. However, the specific role of KSR1 in the formation and progression of fibrotic diseases, such as intrauterine adhesions (IUA), remains unclear. This study aims to investigate KSR1 expression in IUA and the mechanisms underlying its role in promoting IUA progression. KSR1 was found to be significantly overexpressed in the endometrium of both IUA model rats and patients with IUA. KSR1 is positively involved in the regulation of proliferation, migration, and fibrosis (FN1, Collagen I, α-SMA) in immortalized human endometrial stromal cells (THESCs). Furthermore, KSR1 knockdown was observed to inhibit the fibrosis, proliferation, and migration of transforming growth factor-β1 (TGF-β1)-induced THESCs. Further studies demonstrated that the key proteins of the MEK/ERK signaling pathway, p-MEK1 and p-ERK1/2, were significantly overexpressed in the uterus of IUA rats. In vitro rescue experiments confirmed that the MEK/ERK pathway inhibitor U0126 (An ERK inhibitor) effectively suppressed the enhanced fibrosis, proliferation, and migration induced by KSR1 overexpression. In conclusion, this study demonstrates that KSR1 promotes IUA by enhancing proliferation, migration, and fibrosis of endometrial stromal cells via the MEK/ERK signaling pathway.

Contrast-enhanced ultrasonography combined with microbubbles for uterine disorders: Current trends and future perspectives

Uterine disorders, including fibroids, polyps, and carcinomas, represent significant health concerns for women. Conventional diagnostic methods, including ultrasound and magnetic resonance imaging, often lack the sensitivity required to accurately delineate and evaluate these lesions. Consequently, there is a growing need for advanced imaging techniques to enhance both diagnostic precision and therapeutic decision-making. Standard imaging modalities typically provide low resolution, limiting their effectiveness in evaluating uterine pathology and determining optimal treatment strategies. In this context, microbubbles combined with contrast-enhanced ultrasonography offer a promising solution. This technique enhances the visualization of vascular patterns and tissue perfusion, facilitating a more accurate assessment of uterine lesions. Contrast-enhanced ultrasonography is less invasive, is more cost-effective, and offers real-time evaluation of vascular characteristics, making it a valuable tool for diagnosing uterine abnormalities. This review explores the clinical utility of contrast-enhanced ultrasonography with microbubbles in uterine diseases, focusing on its diagnostic accuracy, comparison with traditional imaging techniques, and its potential to improve the management of uterine pathology.

Comparison of hysteroscopic adhesiolysis with electrosurgery instrument or hysteroscopic scissors in the treatment of intrauterine adhesions of infertile or recurrent pregnancy loss women

OBJECTIVE

To investigate pregnancy outcomes following hysteroscopic adhesiolysis (HA) in patients with recurrent pregnancy loss (RPL) or infertility.

DESIGN

Retrospective cohort study.

SETTING

University-affiliated hospital.

SUBJECTS

According to the inclusion and exclusion criteria of this study, finally, a total of 461 subjects were included.

INTERVENTIONS

HA performed using either an electrosurgical instrument or hysteroscopic scissors.

MAIN OUTCOME MEASURES

Pregnancy outcomes post-HA.

RESULTS

A total of 461 patients were included in the study, with follow-up periods ranging from 1 to 6 years. The mean age was 29.48 ± 3.25 years. Hysteroscopic scissors demonstrated greater efficiency in restoring the uterine cavity compared to electrosurgical instruments (88.1% vs. 80.0%, p = 0.025). Post-HA, the pregnancy rate was approximately 75.3% (347/461), with a live birth rate of 55.9% (251/449). No significant differences were found between the electrosurgical instrument and hysteroscopic scissors groups regarding improvements in menstrual flow or fertility outcomes (all p > 0.05). Kaplan-Meier time-dependent cumulative curves for pregnancy and live birth rates after HA indicated that over 50% of patients achieved pregnancy within one year, with the pregnancy rate plateauing at 2 years and the live birth rate at 3 years.

CONCLUSION

Our findings suggest that HA can improve fertility outcomes for patients with RPL or infertility within 2 to 3 years following surgery. Hysteroscopic scissors proved more effective than electrosurgical instruments in restoring the uterine cavity, although no differences were observed between the techniques in terms of menstrual flow or fertility improvements. All in all, our study suggests that standardized HA procedures, the implementation of proactive intraoperative and postoperative measures to prevent the recurrence of intrauterine adhesions (IUA), and an active conception plan following HA are key factors in improving reproductive outcomes for these patients with RPL or infertility.

Ru single-atom nanozymes targeting ROS-ferroptosis pathways for enhanced endometrial regeneration in intrauterine adhesion therapy

Intrauterine adhesion (IUA) presents a significant challenge in gynecology, characterized by excessive fibrosis and compromised reproductive function, leading to severe infertility. Although biocompatible hydrogels integrated with stem cells offer a promising approach for IUA therapy, clinical applications remain limited. Recent studies have highlighted the role of ferroptosis and reactive oxygen species (ROS) in IUA pathogenesis, yet strategies targeting ferroptosis through antioxidant stress are underexplored. This study investigates the therapeutic effects and mechanisms of a Ru-Single-Atom Nanozyme (Ru-SAN) incorporated into chitosan hydrogel for treating IUA. Ru-SAN, which mimics the enzyme activities of catalase, superoxide dismutase, and glutathione peroxidase, effectively clears excess ROS and shows promise in treating oxidative stress-induced diseases. The results demonstrate the superior antioxidative capabilities of Ru-SAN, significantly suppressing the ROS-ferroptosis cycle at the injury site. This creates a favorable microenvironment for post-injury repair by inhibiting inflammation, enhancing mesenchymal-to-epithelial transformation, promoting angiogenesis, and polarizing M2 macrophages. Importantly, it mitigates adverse repair outcomes from inflammation and excessive collagen fiber deposition, ultimately restoring uterine glandular structures and thickness, thereby achieving the ultimate goal of restoring fertility and live birth rates. In conclusion, our study delineates a pioneering therapeutic approach leveraging the antioxidant properties of Ru-SAN to target ferroptosis, thereby offering an efficacious treatment for IUA.

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

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

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

Introduction

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

Methods

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

Results

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

Discussion

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

Integral Roles of the TGFβ Signaling Pathway in Uterine Function and Disease

The uterus is a complex organ that requires precise signaling networks to mediate functions necessary for homeostasis and reproductive processes. The transforming growth factor β (TGFβ) superfamily regulates integral signaling pathways throughout many physiological processes, including cell proliferation, differentiation, and development. In this review, we summarize the current understanding of how the TGFβ signaling family controls key uterine functions, with a specific focus on the endometrium. These uterine functions include endometrial receptivity, implantation, decidualization, placentation, remodeling, and regeneration. Improving our understanding of the signaling networks that regulate these processes is integral to identifying, diagnosing, and treating uterine and reproductive diseases such as endometriosis, adenomyosis, recurrent pregnancy loss, and recurrent implantation failure.

Lactobacillus-Loaded Easily Injectable Hydrogel Promotes Endometrial Repair via Long-Term Retention and Microenvironment Modulation

Regeneration of the injured endometrium, particularly the functional layer, is crucial for the prevention of uterine infertility. At present, clinical treatment using sodium hyaluronate hydrogel injection is limited by its relatively low fluidity, short-term retention, and insufficient bioactive ingredients, so it is necessary to develop an advanced healing-promoting hydrogel. The modulation of the microenvironment by Lactobacillus presents a bioactive component that can facilitate the regeneration of the functional layer. Our study introduces a multifunctional Lactobacillus-loaded poly(N-isopropylacrylamide)-grafted bacterial cellulose (BC-g-PN@L) hydrogel designed with superior injectability and in situ stability. At 25 °C (room temperature), a uniform distribution is achieved with a low injection pressure of only 7.90 kPa. At 37 °C (body temperature), the BC-g-PN@L hydrogel forms a robust three-dimensional nanonetwork, providing space and substance exchange channels for Lactobacillus to maintain its viability and bioactivity. Enhanced by the hydrophobic isopropyl groups in poly(N-isopropylacrylamide) side chains and the rigid bacterial cellulose substrates, the BC-g-PN@L hydrogel exhibits prolonged retention properties in the uterine cavity, persisting for over 21 days. These attributes endow the BC-g-PN@L hydrogel with versatile pro-healing capacity and microenvironment modulation in a rat model of endometrial injury. Our BC-g-PN@L hydrogel promotes the development of advanced injectable hydrogels to facilitate both histological and functional repair of the injured endometrium.

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.

The Application of Nano Drug Delivery Systems in Female Upper Genital Tract Disorders

The prevalence of female reproductive system disorders is increasing, especially among women of reproductive age, significantly impacting their quality of life and overall health. Managing these diseases effectively is challenging due to the complex nature of the female reproductive system, characterized by dynamic physiological environments and intricate anatomical structures. Innovative drug delivery approaches are necessary to facilitate the precise regulation and manipulation of biological tissues. Nanotechnology is increasingly considered to manage reproductive system disorders, for example, nanomaterial imaging allows for early detection and enhances diagnostic precision to determine disease severity and progression. Additionally, nano drug delivery systems are gaining attention for their ability to target the reproductive system successfully, thereby increasing therapeutic efficacy and decreasing side effects. This comprehensive review outlines the anatomy of the female upper genital tract by highlighting the complex mucosal barriers and their impact on systemic and local drug delivery. Advances in nano drug delivery are described for their sustainable therapeutic action and increased biocompatibility to highlight the potential of nano drug delivery strategies in managing female upper genital tract disorders.

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.

Retrospective Analysis of Effective Management Strategies for Primary Amenorrhea of Reproductive Age in Saudi Arabia

Primary amenorrhea, the absence of menstruation by age 15, can have significant implications for reproductive health and overall well-being. This retrospective study aimed to evaluate the effectiveness of various management strategies for primary amenorrhea among women of reproductive age in Saudi Arabia. Medical records of 63 eligible patients from 2018 to 2023 were analyzed, assessing diagnostic methods, treatment modalities, and associated outcomes. The findings revealed that hormonal therapy was the most commonly employed management strategy (50.0%) and demonstrated the highest rate of achieving menstrual regularity (62.5%). Surgical interventions were utilized in 28.1% of cases, with a 50.0% rate of symptom resolution. Lifestyle modifications were less frequent (21.9%) but showed a moderate rate of symptom resolution (35.7%). Logistic regression analysis identified age, underlying etiology, and management strategy as significant predictors of treatment success. Subgroup analyses highlighted the efficacy of hormonal therapy and lifestyle modifications for genetic etiologies, while surgical interventions were more effective for anatomical causes. The study underscores the importance of a comprehensive diagnostic approach and personalized treatment plans tailored to individual patient characteristics. Despite limitations, the findings contribute to the understanding of optimal management strategies for primary amenorrhea and emphasize the need for multidisciplinary collaboration in addressing this complex condition.

Short-term reproductive outcomes analysis and prediction of the modified uterine stent treatment for mild to moderate intrauterine adhesions: experience at a single institution

BACKGROUND

To evaluate the efficacy of modified uterine stent in the treatment of mild-to-moderate intrauterine adhesions and explore the relative indicators affecting prognosis prediction.

METHODS

A total of 115 patients with mild-to-moderate intrauterine adhesions received a modified uterine stent placement after hysteroscopy adhesiolysis. The second-look hysteroscopy operated after 3 months surgery, and the third-look hysteroscopy operated after 6 months surgery if necessary. The stent was removed when the cavity shape was repaired, then the reproductive outcomes were followed up one year.

RESULTS

Menstrual blood volume, endometrial thickness and volume had increased significantly after 3 months surgery. The rates of cavity repaired were 86.96% (100/115) after 3 months surgery and 100% (115/115) after 6 months surgery cumulatively. Endometrial thickness after 3-months surgery was positively associated with uterine cavity shape repaired (P<0.01). The receive operating characteristic (ROC) curve showed the rate of uterine cavity shape repaired predicted by the model was 0.92, based on the endometrial thickness after 3-months surgery. The rate of pregnancy was 86.09% (99/115) in one year, while the rate of miscarriage accounted for 26.26% (26/99). The median time interval between stent removal and subsequent conception was 3 months. It showed adhesion recurrence was the risk factor for subsequent pregnancy (P<0.01).

CONCLUSIONS

A modified uterine stent placement under hysteroscopy was an effective approach for mild-to-moderate intrauterine adhesions, which is easy to operate and worthy for clinical promotion. Endometrial thickness measured by ultrasonography probably has predictive value in adhesion recurrence and subsequent pregnancy.

TRIAL REGISTRATION

ChiCTR2100051524. Date of registration (retrospectively registered): 26/09/2021.

Characteristics of the hormonal background in women with abnormal uterine bleeding and extragenital disorders

OBJECTIVE

Aim: To establish the peculiarities of the hormonal background in women with abnormal uterine bleeding and extragenital disorders.

PATIENTS AND METHODS

Materials and Methods: The study involved examination of 100 women of reproductive age with concomitant ED and AUB (MG). CG included 50 healthy women. MG women were additionally divided into subgroups depending on the detected pathological changes in the uterine cavity. When examining the hormonal status, concentrations of FSH, LH, estradiol, progesterone, and leptin in BS were determined. Additionally, the level of 25-hydroxyvitamin D ((25-OH) D) was determined.

RESULTS

Results: The decrease in FSH level in subgroups of GP, PSL, EH, EHL was 1.8-2.4 times (KWT, p<0.01). LH in BS of MG patients was statistically lower than that of CG patients (MWT, p=0.0083). The lowest level of LH was registered in patients with EHL, which was 2 times lower than this indicator in CG. A statistically significant increase in the level of estradiol was registered in 73% of MG patients (MWT, p=0.044). The lowest level of progesterone was registered in patients with EHL - 8.40, which is 4.7 times lower than in CG (MWT, p=0.0021). A statistically significant increase in the level of leptin in BS was observed in MG patients (KWT, p=0.0021). The highest level of leptin was found in women with AFP, 2.3 times higher than CG indicators. A statistically significant correlation between the level of leptin and BMI (r=0.86, p=0.011) and a statistically significant (p=0.023) correlation between the level of leptin and estradiol in BS of patients of the examined groups (r=0.42) were revealed. In 87% of MG women, vitamin D deficiency was observed in BS (KWT, p=0.03). A statistically significant (p=0.01) negative correlation between the level of estradiol and vitamin D in the BS of female patients was revealed (r=-0.61, p=0.01).

CONCLUSION

Conclusions: Women of reproductive age with AUB and ED were found to have disorders in the hypothalamic-pituitary-ovarian system. Most patients are characterized by an elevated level of leptin, the concentration of which is closely correlated with BMI, and an elevated level of estradiol is correlated with the level of vitamin D.