Meta-analysis on the use of hyaluronic acid gel to prevent intrauterine adhesion after intrauterine operations

Incidence of intrauterine adhesion after ultrasound-guided manual vacuum aspiration (USG-MVA) for first-trimester miscarriages: a prospective cohort study

PURPOSE

Ultrasound-guided manual vacuum aspiration (USG-MVA) is a feasible and effective outpatient treatment to treat early pregnancy loss.

METHODS

This was a prospective observational study at a university-affiliated hospital. All women undergoing either a USG-MVA or electric vacuum aspiration (EVA) were invited to return 3-6 months later for follow-up at which women completed a questionnaire to document their post-evacuation menstrual and reproductive history, and underwent a hysteroscopy if they were not pregnant. The severity of intrauterine adhesion (IUA), if present, was graded (Stage I-III) according to the American fertility society classification.

RESULTS

A total of 292 women had a hysteroscopy after their initial surgical evacuation, USG-MVA 169(57.9%) versus EVA 123(42.1%). Women undergoing EVA as opposed to a USG-MVA had a 12.9% higher incidence of IUA (24.1% vs. 37.0%, p = 0.042) equivalent to 1.84 times higher risk (95% CI 1.01-3.34; p = 0.048). Women having EVA continued to show an increased but not statistically significant trend towards an increased risk of IUA after adjusting for the type of miscarriage (aOR = 1.3; 95% CI 0.66-2.50; p = 0.46).

CONCLUSION

There were no significant differences in their reproductive outcomes and fewer women post-USG-MVA complained of hypomenorrhea. IUA may still occur in women undergoing USG-MVA but it is lower than the rate in women undergoing EVA. Clinical trials registry The trial was registered with the Centre for Clinical Research and Biostatistics - Clinical Trials Registry (CCRBCTR), a partner registry of the WHO Primary Registry-Chinese Clinical Trials Registry (ChiCTR) with a Unique Trial Number: CUHK_CCRB00541 on 22 Dec 2016.

VitroGel-loaded human MenSCs promote endometrial regeneration and fertility restoration

Introduction: Intrauterine adhesions (IUA), also known as Asherman's syndrome, is caused by trauma to the pregnant or non-pregnant uterus, which leads to damaged endometrial basal lining and partial or total occlusion of the uterine chambers, resulting in abnormal menstruation, infertility, or recurrent miscarriage. The essence of this syndrome is endometrial fibrosis. And there is no effective treatment for IUA to stimulate endometrial regeneration currently. Recently, menstrual blood-derived stem cells (MenSCs) have been proved to hold therapeutic promise in various diseases, such as myocardial infarction, stroke, diabetes, and liver cirrhosis. Methods: In this study, we examined the effects of MenSCs on the repair of uterine adhesions in a rat model, and more importantly, promoted such therapeutic effects via a xeno-free VitroGel MMP carrier. Results: This combined treatment reduced the expression of inflammatory factors, increased the expression of anti-inflammatory factors, restricted the area of endometrial fibrosis, diminished uterine adhesions, and partially restored fertility, showing stronger effectiveness than each component alone and almost resembling the sham group. Discussion: Our findings suggest a highly promising strategy for IUA treatment.

Extracellular Vesicles Derived from Mesenchymal Stem Cells as Cell-Free Therapy for Intrauterine Adhesion

Intrauterine adhesion (IUA) can occur after trauma to the basal layer of the endometrium, contributing to severe complications in females, such as infertility and amenorrhea. To date, the proposed therapeutic strategies are targeted to relieve IUA, such as hysteroscopic adhesiolysis, Foley catheter balloon, and hyaluronic acid injection have been applied in the clinic. However, these approaches showed limited effects in alleviating endometrial fibrosis and thin endometrium. Mesenchymal stem cells (MSCs) can offer the potential for endometrium regeneration owing to reduce inflammation and release growth factors. On this basis, MSCs have been proposed as promising methods to treat intrauterine adhesion. However, due to the drawbacks of cell therapy, the possible therapeutic use of extracellular vesicles released by stem cells is raising increasing interest. The paracrine effect, mediated by MSCs derived extracellular vehicles (MSC-EVs), has recently been suggested as a mechanism for their therapeutic properties. Here, we summarizes the main pathological mechanisms involved in intrauterine adhesion, the biogenesis and characteristics of extracellular vesicles, explaining how these vesicles could provide new opportunities for MSCs.

HYSTEROSCOPIC MYOMECTOMY

Leiomyomas are the most common pelvic tumors. Submucosal fibroids are a common cause of abnormal bleeding and infertility. Hysteroscopic myomectomy is the definitive management of symptomatic submucosal fibroids, with high efficacy and safety. Several techniques have been introduced over time and will be covered in depth in this manuscript. Advances in optics, fluid management, electrosurgery, smaller diameter scopes, and tissue removal systems, along with improved training have contributed to improving the safety and efficiency of hysteroscopic myomectomy.

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

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

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

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

Application of Bioactive Hydrogels for Functional Treatment of Intrauterine Adhesion

Intrauterine adhesion (IUA) is a common endometrial disease and one of the main causes of infertility in women of childbearing age. Current treatment strategies, such as hysteroscopic adhesion resection, hysteroscopic transcervical resection of adhesion (TCRA), the use of local hormone drugs, and anti-adhesion scaffold implantation, do not provide a satisfactory pregnancy outcome for moderate-severe IUA, which presents a great challenge in reproductive medicine. With the development of material engineering, various bioactive and functional hydrogels have been developed using natural and synthetic biomaterials. These hydrogels are not only used as barely physical barriers but are also designed as vectors of hormone drugs, growth factors, and stem cells. These characteristics give bioactive hydrogels potentially important roles in the prevention and treatment of IUA. However, there is still no systematic review or consensus on the current advances and future research direction in this field. Herein, we review recent advances in bioactive hydrogels as physical anti-adhesion barriers, in situ drug delivery systems, and 3D cell delivery and culture systems for seeded cells in IUA treatment. In addition, current limitations and future perspectives are presented for further research guidance, which may provide a comprehensive understanding of the application of bioactive hydrogels in intrauterine adhesion treatment.

Focus on the Primary Prevention of Intrauterine Adhesions: Current Concept and Vision

Intrauterine adhesion (IUA), and its severe form Asherman syndrome (Asherman’s syndrome), is a mysterious disease, often accompanied with severe clinical problems contributing to a significant impairment of reproductive function, such as menstrual disturbance (amenorrhea), infertility or recurrent pregnancy loss. Among these, its correlated infertility may be one of the most challenging problems. Although there are many etiologies for the development of IUA, uterine instrumentation is the main cause of IUA. Additionally, more complicated intrauterine surgeries can be performed by advanced technology, further increasing the risk of IUA. Strategies attempting to minimize the risk and reducing its severity are urgently needed. The current review will expand the level of our knowledge required to face the troublesome disease of IUA. It is separated into six sections, addressing the introduction of the normal cyclic endometrial repairing process and its abruption causing the formation of IUA; the etiology and prevalence of IUA; the diagnosis of IUA; the classification of IUA; the pathophysiology of IUA; and the primary prevention of IUA, including (1) delicate surgical techniques, such as the use of surgical instruments, energy systems, and pre-hysteroscopic management, (2) barrier methods, such as gels, intrauterine devices, intrauterine balloons, as well as membrane structures containing hyaluronate–carboxymethylcellulose or polyethylene oxide–sodium carboxymethylcellulose as anti-adhesive barrier.

Recent developments in bio-scaffold materials as delivery strategies for therapeutics for endometrium regeneration

Intrauterine adhesions (IUAs) refer to the repair disorder after endometrial injury and may lead to uterine infertility, recurrent miscarriage, abnormal menstrual bleeding, and other obstetric complications. It is a pressing public health issue among women of childbearing age. Presently, there are limited clinical treatments for IUA, and there is no sufficient evidence that these treatment modalities can effectively promote regeneration after severe endometrial injury or improve pregnancy outcome. The inhibitory pathological micro-environment is the main factor hindering the repair of endometrial damaged tissues. To address this, tissue engineering and regenerative medicine have been achieving promising developments. Particularly, biomaterials have been used to load stem cells or therapeutic factors or construct an in situ delivery system as a treatment strategy for endometrial injury repair. This article comprehensively discusses the characteristics of various bio-scaffold materials and their application as stem cell or therapeutic factor delivery systems constructed for uterine tissue regeneration.

Reproductive performance of women with and without intrauterine adhesions following recurrent dilatation and curettage for miscarriage: long-term follow-up of a randomized controlled trial

STUDY QUESTION

Are the long-term reproductive outcomes following recurrent dilatation and curettage (D&C) for miscarriage in women with identified and treated intrauterine adhesions (IUAs) comparable to women without IUAs.

SUMMARY ANSWER

Reproductive outcomes in women with identified and treated IUAs following recurrent D&C for miscarriage are impaired compared to women without IUAs; fewer ongoing pregnancies and live births are achieved with a prolonged time to a live birth.

WHAT IS KNOWN ALREADY

The Prevention of Adhesions Post Abortion (PAPA) study showed that application of auto-crosslinked hyaluronic acid (ACP) gel, an absorbable barrier in women undergoing recurrent D&C for miscarriage resulted in a lower rate of IUAs, 13% versus 31% (relative risk 0.43, 95% CI 0.22 to 0.83), lower mean adhesion score and significant less moderate to severe IUAs. It is unclear what the impact is of IUAs on long-term reproductive performance.

STUDY DESIGN, SIZE, DURATION

This was a follow-up of the PAPA study, a multicenter randomized controlled trial evaluating the application of ACP gel in women undergoing recurrent D&C for miscarriage. All included women received a diagnostic hysteroscopy 8-12 weeks after randomization to evaluate the uterine cavity and for adhesiolysis if IUAs were present. Here, we present the reproductive outcomes in women with identified and treated IUAs versus women without IUAs, 46 months after randomization.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Between December 2011 and July 2015, 152 women with a first-trimester miscarriage with at least one previous D&C, were randomized for D&C alone or D&C with immediate intrauterine application of ACP gel. Participants were approached at least 30 months after randomization to evaluate reproductive performance, obstetric and neonatal outcomes and cycle characteristics. Additionally, the medical files of all participants were reviewed. Main outcome was ongoing pregnancy. Outcomes of subsequent pregnancies, time to conception and time to live birth were also recorded.

MAIN RESULTS AND THE ROLE OF CHANCE

In women pursuing a pregnancy, 14/24 (58%) ongoing pregnancies were recorded in women with identified and treated IUAs versus 80/89 (90%) ongoing pregnancies in women without IUAs odds ratio (OR) 0.18 (95% CI 0.06 to 0.50, P-value <0.001). Documented live birth was also lower in women with IUAs; 13/24 (54%) with versus 75/89 (84%) without IUAs, OR 0.22 (95% CI: 0.08 to-0.59, P-value 0.004). The median time to conception was 7 months in women with identified and treated IUAs versus 5 months in women without IUAs (hazard ratio (HR) 0.84 (95% CI 0.54 to 1.33)) and time to conception leading to a live birth 15 months versus 5.0 months (HR 0.54 (95% CI: 0.30 to 0.97)). In women with identified and treated IUAs, premature deliveries were recorded in 3/16 (19%) versus 4/88 (5%) in women without IUAs, P-value 0.01. Complications were recorded in respectively 12/16 (75%) versus 26/88 (30%), P-value 0.001. No differences were recorded in mean birth weight between the groups.

LIMITATIONS, REASONS FOR CAUTION

In the original PAPA study, randomization was applied for ACP gel application. Comparing women with and without IUAs is not in line with the randomization and therefore confounding of the results cannot be excluded. IUAs, if visible during routine hysteroscopy after randomization were removed as part of the study protocol; the influence of IUAs on reproductive outcome may therefore be underestimated. Women undergoing a recurrent D&C for miscarriage were included, a specific group likely to generate clinically significant adhesions. The findings should therefore not be generalized to all women undergoing D&C for miscarriage.

WIDER IMPLICATIONS OF THE FINDINGS

As IUAs have an impact on reproductive performance, even after hysteroscopic adhesiolysis, primary prevention is essential. Expectative and medical management should therefore be considered as serious alternatives for D&C in women with a miscarriage. In case D&C is necessary, application of ACP gel should be considered.

STUDY FUNDING/COMPETING INTEREST(S)

The original PAPA study (NTR 3120) was an investigator initiated study that was funded by the Foundation for scientific investigation in Obstetrics and Gynaecology of the Saint Lucas Andreas Hospital (currently renamed OLVG Oost), SWOGA. The syringes containing ACP gel were received from Anika Therapeutics, the manufacturer of Hyalobarrier® Gel Endo. The current follow-up study was also an investigator-initiated study without funding. The funder and sponsor had no role in the design of this follow-up study, data collection, data analysis, data interpretation, trial design, patient recruitment, writing of the report or any aspect pertinent to the study. ABH, RAL, JAFH and JWRT have no conflict to declare. HAMB reports being a member of safety board research Womed.

TRIAL REGISTRATION NUMBER

Netherlands Trial Register NTR 3120.

Efficacy of Applying Hyaluronic Acid Gels in the Primary Prevention of Intrauterine Adhesion after Hysteroscopic Myomectomy: A Meta-Analysis of Randomized Controlled Trials

Intrauterine adhesion (IUA), which mainly occurs after intrauterine surgery or an inflammatory process, is an important but often neglected condition in women of reproductive age. The presentation of IUA varies greatly, ranging from symptom-free to severe, with amenorrhea or infertility. With much advanced development of intrauterine instruments, more intrauterine diseases can be successfully cured by hysteroscopic surgery. Among these, submucosal myoma is one of the best examples. Submucosal myomas are often related to abnormal bleeding, anemia, and possible infertility or miscarriage. However, submucosal myoma after hysteroscopic myomectomy may be complicated by IUA in various grades of severity, and its incidence and prevalence might be nearly one-quarter to one-third of patients, suggesting an urgent need for efforts to decrease the risk of developing IUA after hysteroscopic myomectomy. Many strategies have been reported to be useful for this purpose, and intrauterine application of anti-adhesive gels, such as polyethylene oxide–sodium carboxymethylcellulose (PEO-NaCMC) or auto-crosslinked hyaluronic acid (ACHA), has become increasingly popular in routine clinical practice. This meta-analysis is aimed at investigating the effect of ACHA on the primary prevention of IUA formation after hysteroscopic myomectomy. A pooled analysis of three studies (hysteroscopic surgeries for fibroids, polyps, and septum) including 242 women showed that using PEO-NaCMC or ACHA gel decreased the IUA rate with an odds ratio (OR) of 0.364 (95% confidence interval (CI) 0.189–0.703, p = 0.03). Pooled analysis of two studies that limited the use of ACHA in 119 women showed that the application of ACHA gel for the primary prevention of IUA in patients after hysteroscopic myomectomy led to a statistically significant reduction of the development of IUA postoperatively (OR 0.285, 95% CI 0.116–0.701, p = 0.006). All of this suggests that the use of ACHA gel in patients after hysteroscopic myomectomy could significantly reduce de novo IUA, although more evidence is needed.

Mini-Review of the New Therapeutic Possibilities in Asherman Syndrome-Where Are We after One Hundred and Twenty-Six Years?

Asherman syndrome is a multifaceted condition describing the partial or complete removal of the uterine cavity and/or cervical canal. It is a highly debatable topic because of its pronounced influence on both reproductive outcomes and gynaecologic symptoms. The latest reports demonstrated that trauma to the endometrium is the main cause of intrauterine adhesion formation. Left untreated, such adhesions gradually lead to a range of repercussions ranging from mild to severe. Considering the lack of non-invasive approaches, the advent of hysteroscopy has revolutionized the entire field, being otherwise considered the most efficient tool offering new directions and amplifying the chances of treating the Asherman syndrome.

Crosslinked Hyaluronic Acid Gels for the Prevention of Intrauterine Adhesions after a Hysteroscopic Myomectomy in Women with Submucosal Myomas: A Prospective, Randomized, Controlled Trial

Intrauterine adhesion (IUA), fibrosis, and scarring resulting from damage to the endometrium is a rare but serious clinical disease, contributing to a significant impairment of reproductive function. Uterine instrumentation, especially that of a hysteroscopic myomectomy, has become the main cause of IUA. Therefore, a prospective randomized controlled study to assess the effectiveness and short-term safety of the use of hyaluronic acid gels in the prevention of IUA after a hysteroscopic myomectomy and an evaluation of the characteristics of IUA observed at follow-up are presented here. A total of 70 patients were analyzed at the end of 16 March 2020. The results show that the incidence of IUA in women who underwent a hysteroscopic myomectomy is 21.4% (15/70), overall. Women treated with hyaluronic acid gels have a statistically significantly lower incidence of IUAs than non-treated women (12.8% vs. 39.1%, p = 0.012). In addition, women in the anti-adhesive gel treatment group had a dramatically reduced severity of IUA than women in the no-treatment group (p = 0.002). Further analysis shows that the International Federation of Gynecology and Obstetrics (FIGO) classification type and the use of anti-adhesive gels are independent factors associated with moderate and severe degrees of IUA formation. The results here highlight the significant therapeutic benefits of the application of hyaluronic acid gels in women undergoing a hysteroscopic myomectomy, especially for those patients with a uterine myoma classified as FIGO type 2. Since the risk of IUA after a hysteroscopic myomectomy is high, especially for patients who have not received prophylactic anti-adhesive gels, the application of hyaluronic acid gels as a prevention strategy is highly recommended. More studies are encouraged to confirm our observation.