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

Thermosensitive hydrogel as a sustained release carrier for mesenchymal stem cell-derived extracellular vesicles in the treatment of intrauterine adhesion

Intrauterine adhesion (IUA), a prevalent etiology of female infertility, is attributed to endometrial damage. However, conventional therapeutic interventions for IUA are plagued by high recurrence rates. Human umbilical cord mesenchymal stem cell-derived extracellular vesicles (hUCMSC-EVs) demonstrate the promising therapeutic effects on IUA, but the current efficacy of extracellular vesicles (EVs) is hindered by lower retention and bioavailability. In this study, a thermosensitive hydrogel was utilized as a prolonged release carrier to improve the retention and bioavailability of hUCMSC-EVs in IUA treatment. The hydrogel-EVs complex effectively prolonged EVs retention in human endometrial stromal cells and an IUA mouse model. The complex exhibited superior protection against cellular injury, significantly alleviated endometrial damage, inhibited fibrosis, suppressed inflammation, and improved fertility compared to EVs alone. The results indicated that thermosensitive hydrogel enhanced the therapeutic capacity of EVs for IUA by prolonging their retention in the uterine environment. The hydrogel-EVs complex provides a novel strategy for the sustained release of hUCMSC-EVs in the treatment of IUA.

Pregnancy and perinatal outcomes in pregnancies following frozen embryo transfer (FET) after transcervical resection of adhesions (TCRA): A retrospective cohort study with propensity score matching analysis

OBJECTIVE

To compare the pregnancy and perinatal outcomes of frozen-thawed embryo transfer (FET) in patients following transcervical resection of adhesions (TCRA) versus patients with normal uterine morphology, and to investigate the factors influencing pregnancy outcomes in patients undergoing FET after TCRA.

METHODS

We retrospectively analyzed FET cycles from September 2014 to September 2023, comparing patients with normal uterine morphology to those with intrauterine adhesions (IUAs) treated with TCRA. Propensity score matching (PSM) adjusted for confounding factors. LASSO regression and multivariate logistic regression identified predictors of outcomes, which were visually represented in nomograms. Model performance was assessed using calibration curves, ROC curves, and DCA, with bootstrap method for internal validation.

RESULTS

Post-PSM analysis showed higher live birth rates in patients with normal uterine morphology after clinical pregnancy (75.1% vs. 61.7%, P < 0.001). No significant differences were noted in clinical pregnancy rates and perinatal outcomes between the groups. Factors influencing clinical pregnancy in FET after TCRA included basal progesterone levels, endometrial thickness, parity, infertility cause, embryo stage at transfer, number and quality of embryos transferred, IUA severity, and TCRA surgical procedures. Body mass index, basal LH levels, and day 14 HCG levels post-embryo transfer were determinants of live birth outcome.

CONCLUSION

FET cycles following TCRA showed a lower rate of successful live births, but TCRA did not increase adverse perinatal outcome risks. Our study introduces an innovative predictive model for clinical pregnancy and live birth outcomes in patients undergoing FET following TCRA, addressing a significant void in existing research.

Synthesis of Cyclodextrin-Based Multifunctional Biocompatible Hydrogels and Their Use in the Prevention of Intrauterine Adhesions (Asherman's Syndrome) after Surgical Injury

Asherman's syndrome, which can occur during the regeneration of damaged uterine tissue after surgical interventions, is a significant health problem in women. This study aimed to acquire and characterize cyclodextrin-based hydrogels, which can be used to prevent Asherman's syndrome, and investigate their effectiveness with biomedical applications. A series of hydrogels were synthesized from the cross-linking of β-cyclodextrin and different polyphenols with epoxy-functional PEG. Their chemical, physical, and biological properties were subsequently determined. The results demonstrated that the cyclodextrin-based hydrogels had a porous structure, high swelling ratio, good injectability, drug release ability, and antioxidant activity. Cell culture results illustrated that the hydrogels had no significant cytotoxicity toward L929 fibroblast cells. Considering all properties, the β-CD-PEG-600-Ec hydrogel showed the most satisfactory properties rather than other ones. The potential of this hydrogel in preventing Asherman's syndrome was evaluated in a rat model. The results revealed that the β-estradiol- and melatonin-loaded cyclodextrin-based multifunctional hydrogel group both structurally and mechanically showed an antiadhesion effect in the uterus and a therapeutic effect on the damage with the β-estradiol and melatonin that it contains compared to the Asherman (ASH) group. This double drug-loaded hydrogel can be a promising candidate for preventing Asherman's syndrome due to its versatile properties.

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.

Incorporation of Decidual Stromal Cells Derived Exosomes in Sodium Alginate Hydrogel as an Innovative Therapeutic Strategy for Advancing Endometrial Regeneration and Reinstating Fertility

Intrauterine adhesion (IUA) stands as a prevalent medical condition characterized by endometrial fibrosis and scar tissue formation within the uterine cavity, resulting in infertility and, in severe cases, recurrent miscarriages. Cell therapy, especially with stem cells, offers an alternative to surgery, but concerns about uncontrolled differentiation and tumorigenicity limit its use. Exosomes, more stable and immunogenicity-reduced than parent cells, have emerged as a promising avenue for IUA treatment. In this study, a novel approach has been proposed wherein exosomes originating from decidual stromal cells (DSCs) are encapsulated within sodium alginate hydrogel (SAH) scaffolds to repair endometrial damage and restore fertility in a mouse IUA model. Current results demonstrate that in situ injection of DSC-derived exosomes (DSC-exos)/SAH into the uterine cavity has the capability to induce uterine angiogenesis, initiate mesenchymal-to-epithelial transformation (MET), facilitate collagen fiber remodeling and dissolution, promote endometrial regeneration, enhance endometrial receptivity, and contribute to the recovery of fertility. RNA sequencing and advanced bioinformatics analysis reveal miRNA enrichment in exosomes, potentially supporting endometrial repair. This finding elucidates how DSC-exos/SAH mechanistically fosters collagen ablation, endometrium regeneration, and fertility recovery, holding the potential to introduce a novel IUA treatment and offering invaluable insights into the realm of regenerative medicine.

Intrauterine adhesion

Intrauterine adhesions (IUA) occurred in the reproductive-age women are a big economic and health problem, resulting in severe impairment of social, psychological and physical function of the female genital organs. IUA-related symptoms or signs are varied greatly from free of symptoms or ambiguous symptoms (an incidental finding during the intervention) to ceased menstruation and loss of fecundability. The underlying pathophysiology is not completely understood, but intrauterine damage with broken basal layers of the endometrium formatting scar tissues or fibrosis in the endometrium with subsequently causing partial or complete occlusion of the uterine cavity may be a well-accepted hypothesis. Previously, infection is the most common cause to develop IUA, but now, intrauterine surgery may be a critical cause contributing to the majority of cases of IUA. In the current review, update information about the etiology, epidemiology, pathophysiology, sequelae and prevention of IUA will be renewed. We emphasize the importance of awareness of IUA, and primary prevention should be considered in the routine clinical practice if intrauterine surgery has been applied, based on uncertainty of ideal treatment for the established IUA and unpredictable outcomes after IUA treatment. So far, evidence supports that hyaluronic acid with/without other strategy is the most valuable and effective method to reduce the formation and re-formation of IUA as well as to achieve the best fertility outcome.

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.

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.