The impact of chronic endometritis on endometrial fibrosis and reproductive prognosis in patients with moderate and severe intrauterine adhesions: a prospective cohort study

Correlation of hysteroscopic findings of chronic endometritis with CD138 immunohistochemistry and their correlation with pregnancy outcomes

PURPOSE

To investigate the correlation between hysteroscopic findings of chronic endometritis and CD138 immunohistochemistry positive in endometritis and to analyze the pregnancy outcomes and associated risk factors following embryo transfer in women diagnosed with chronic endometritis via hysteroscopy.

METHODS

A retrospective observational study carried out at the Reproductive Medicine Center of Tangdu Hospital of Air Force Medical University, from January 2021 to December 2021, was performed by obtaining data from 194 medical records of women who underwent hysteroscopies for infertility and were diagnosed with chronic endometritis based on Delphi criteria. Spearman correlation analysis was used to evaluate the correlation between hysteroscopic findings and endometrial CD138 immunohistochemistry. The study also observed the differences in relevant indexes between the CD138-positive and CD138-negative groups after embryo transfer and analyzed factors influencing implantation failure using logistic regression analysis.

RESULTS

The correlation analysis between hysteroscopic findings and CD138 immunohistochemistry showed that micropolyps were correlated with CD138 immunohistochemistry positivity. The correlation coefficient was 0.32 (P < 0.01). After embryo transfer, the clinical pregnancy rate of the CD138-positive group was lower compared to that of the CD138-negative group [64.79% (46/71) vs. 81.30% (100/123), P < 0.05]. The results of the multivariate logistic regression analysis revealed that age (P = 0.43) and CD138 immunohistochemistry positivity (P = 0.008) were the independent risk factors for predicting whether or not embryo implantation was successful.

CONCLUSION

Hysteroscopic findings do not correlate strongly with endometrial CD138 immunohistochemistry, and chronic endometritis cannot be diagnosed by hysteroscopy alone. CD138 immunohistochemistry positivity is an independent factor contributing to the decrease in clinical pregnancy rate following embryo transfer.

Risk factors of chronic endometritis in women who have undergone hysteroscopy: a prospective nested case-control study

There is limited research on risk factors for chronic endometritis regarding reproductive history and clinical symptoms. Thus, this nested case-control study identified risk factors for chronic endometritis in women who have undergone hysteroscopy. Endometrial tissue sections were obtained from 502 women with intrauterine disorders who underwent hysteroscopy. Chronic endometritis was diagnosed via CD138 immunostaining. The women were divided into two groups: 271 women without chronic endometritis and 231 women with chronic endometritis. The prevalence of chronic endometritis was 46%. Univariate logistic regression revealed that prolonged menstruation and intermenstrual bleeding were associated with chronic endometritis, and subsequent multivariate logistic regression analyses showed that these were further independently associated. With univariable logistic regression, the gravidity and abortion history were correlated with chronic endometritis; however, no significant correlation was found with the adjusted odds ratio (OR) of 0.74 (95% confidence interval [CI] 0.46-1.19) or 0.76 (95% CI 0.58-1.11), respectively. No significant correlation was found between caesarean section history and the rates of chronic endometritis. No significant difference was found in all other variables between the three groups with > 5, ≤ 5 plasma cells and in a unknown group. Prolonged menstruation and intermenstrual bleeding were risk factors associated with chronic endometritis. Chronic endometritis should be considered and CD138 immunohistochemical examination should be recommended in women with these symptoms.

Analysis of factors affecting the prognosis of patients with intrauterine adhesions after transcervical resection of adhesions

OBJECTIVES

To study the factors affecting the prognosis of patients with intrauterine adhesions (IUAs) after transcervical resection of adhesions (TCRA), analyze the reproductive outcome, and guide prognostic improvements.

DESIGN

Prospective study.

PATIENTS

Our study included 292 patients diagnosed with IUAs who underwent follow-up office hysteroscopy at Shenyang Women's and Children's Hospital between June 2018 and June 2022.

INTERVENTIONS

Patients were divided into case (52 patients whose hysteroscopy results indicated the presence of IUAs) and nocase (240 patients whose uterine cavity had returned to normal shape without obvious adhesion) groups on the basis of the results of a 2-month follow-up hysteroscopy following TCRA. Clinical data were collected and compared with various influencing factors, and the combined effect of these factors was assessed using multifactorial logistic regression analysis. A nomogram prediction model was constructed and internally validated on the basis of multifactorial analysis.

MAIN OUTCOME MEASURES

Intrauterine re-adhesion was observed at a 2-month follow-up after TCRA.

RESULTS

Postoperative re-adhesion occurred in 52 of 292 patients with IUAs. Multifactorial binary logistic regression analysis showed that IUA barrier gel reapplication 5 days after TCRA was a protective factor. In contrast, the preoperative American Fertility Society scores demonstrated that severe IUAs and chronic endometritis were risk factors. The results of the multifactorial analysis were used to build a nomogram model, and the area under the curve value of the nomogram model for predicting postoperative recurrence was 0.914 (95% confidence interval: 0.864-0.956). The bootstrap method was subsequently used to resample 1,000 times for internal validation. The results showed that the internal validation C-index was 0.9135, and the calibration and ideal curves were well-matched.

CONCLUSION

The prognosis of patients with IUAs after TCRA is related to the severity of preoperative IUAs, presence of chronic endometritis, and IUA barrier gel reapplication 5 days after TCRA. Therefore, clinicians should monitor patients using targeted data to reduce recurrence risk after TCRA and improve the prognosis of patients with IUAs.

Vaginal microbiome dysbiosis as a novel noninvasive biomarker for detection of chronic endometritis in infertile women

OBJECTIVE

To identify the vaginal microbial signature in women with chronic endometritis (CE) and investigate the potential of vaginal microbiome characterization as a novel diagnostic tools for CE.

METHODS

A cross-sectional study was conducted to compare the characteristics of the vaginal microbiome in 98 women who underwent endometrial biopsy for routine clinical inspection of infertility (49 women diagnosed with CE and 49 with non-CE). The vaginal microbiome was analyzed using 16S ribosomal RNA gene amplicon sequencing. The study included an analysis of diversity, bacterial abundance, and microbial function. In addition, microbial markers were identified, and a CE classifier was developed.

RESULTS

The relative abundances of genera, including Bifidobacterium, Prevotella and Gardnerella, were found to be different between the two groups. Analysis of the Kyoto Encyclopedia of Genes and Genomes pathways reported differential expression in metabolism-related pathways in the two groups. We identified four microbial markers of CE (Enterobacter, Prevotella, Faecalibacterium, and Phascolarctobacterium) and developed a predictive classifier for diagnosing CE, achieving an area under the curve of 83.26%.

CONCLUSION

The results of the current study revealed that, compared with the non-CE controls, patients with CE have a different vaginal microbiota, highlighting the diagnostic significance of the vaginal microbiome as a promising noninvasive biomarker in detecting CE.

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.

Correlation between hysteroscopic features and specific microbial species in women with chronic endometritis

Objective and rationale

Chronic endometritis (CE) has recently been associated with unexplained infertility and recurrent miscarriages. The current gold standard for CE detection is histopathological examination. However, office hysteroscopy and endometrial cultures are also significant, due to the possible link between CE and various microorganisms. Bacterial colonization of the endometrium has been associated with reduced success rates of in vitro fertilisation embryo transfer. Few studies have tried to correlate CE hysteroscopy findings with pathogenic microorganisms. This prospective cohort study sought to establish whether hysteroscopic diagnostic lesions correlate with specific microbial species.

Methods

The study encompassed women undergoing diagnostic tests for a range of subfertility health issues. 189 women completed the standard office diagnostic hysteroscopy (DH). 181 had also endometrial samples taken for microbial culture investigation. Correlation analysis (χ2 and Fisher's exact test) between hysteroscopic findings suggestive of CE and endometrial cultures was carried out. Logistic regression models were also fitted to measure whether a positive endometrial culture could affect CE conditions.

Results

A significant association of E. coli was observed between the hysteroscopically characterized CE + group with focal hyperplasia, when compared to the non-CE group. Logistic regression analysis revealed that women positive for E. coli were 4.423 times more likely to have focal endometrial hyperplasia. No other significant correlations were identified between DH and positive endometrial cultures.

Conclusions

The presence of E. coli in the endometrium was significantly correlated with focal hyperplasia findings from hysteroscopy, emphasizing the importance of microbial cultures in the diagnosis and targeted treatment of CE in women with subfertility.

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.

The timing for embryo transfer after antibiotic therapy for chronic endometritis

OBJECTIVE

To explore the optimal timing of embryo transfer after the first round treatment of chronic endometritis (CE) in vitro.

MATERIALS AND METHODS

A total of 184 patients were recruited from a retrospective analysis of a large university-affiliated reproduction center in 2021. Some people chose to undergo embryo transfer in the same menstrual cycle with the first round of antibiotic treatment (Group 1, n = 29). Others received embryo transfer in the next cycle after the first round of treatment (Group 2, n = 69) or even one cycle later (Group 3，n = 96).

RESULTS

Patients in Group 1 got significantly lower biochemical pregnancy rate and clinical pregnancy rate and live birth rate than Group 2 (p < 0.05) and also Group 3 (p < 0.05). Then after comparing the influence factors, we found embryo transfer in the next cycle after antibiotic treatment had a higher clinical pregnancy rate than group 1 (OR = 3.2 p < 0.05) and group 3(OR = 2.5, p < 0.05). The live birth rate in group 2 was higher than group 1(OR = 3.5, p < 0.05).

CONCLUSION

These findings illustrate that embryo transfer in the next menstrual cycle is the optimal time. Embryo transfer in the same menstrual cycle with the first round of treatment reduces the pregnancy rate.

Mechanism of Smilax china L. in the treatment of intrauterine adhesions based on network pharmacology, molecular docking and experimental validation

BACKGROUND

Smilax china L. (SCL) is a traditional herbal medicine for the potential treatment of intrauterine adhesion (IUA). However, the mechanisms of action have not yet been determined. In this study, we explored the effects and mechanisms of SCL in IUA by network pharmacology, molecular docking and molecular biology experiments.

METHODS

Active ingredients and targets of SCL were acquired from TCMSP and SwissTargetPrediction. IUA-related targets were collected from the GeneCards, DisGeNET, OMIM and TTD databases. A protein‒protein interaction (PPI) network was constructed by Cytoscape 3.9.1 and analysed with CytoHubba and CytoNCA to identify the core targets. The DAVID tool was used for GO and KEGG enrichment analyses. Furthermore, molecular docking was employed to assess the interaction between the compounds and key targets. Finally, the mechanisms and targets of SCL in IUA were verified by cellular experiments and western blot.

RESULTS

A total of 196 targets of SCL were identified, among which 93 were related to IUA. Topological and KEGG analyses results identified 15 core targets that were involved in multiple pathways, such as inflammation, apoptosis, and PI3K/AKT signalling pathways. Molecular docking results showed that the active compounds had good binding to the core targets. In vitro experiments showed that astilbin (AST), a major component of SCL, significantly reduced TGF-β-induced overexpression of fibronectin (FN), activation of the PI3K/AKT signalling pathway and the expression of downstream factors (NF-κB and BCL2) in human endometrial stromal cells, suggesting that AST ameliorates IUA by mediating the PI3K/AKT/NF-κB and BCL2 proteins.

CONCLUSIONS

AST, a major component of SCL, may be a potential therapeutic agent for IUA. Moreover, its mechanism is strongly associated with regulation of the PI3K/AKT signalling pathway and the downstream NF-κB and BCL2 proteins. This study will provide new strategies that utilize AST for the treatment of IUA.

Punicalagin improves inflammation and oxidative stress in rat model of pelvic inflammatory disease

Pelvic inflammatory disease (PID) is one of the major public health concerns accounting for 30% of infertility and 50% of ectopic pregnancy cases due to severe inflammation and fibrosis. Punicalagin® are known to exhibit potent anti-inflammatory activity. The aim of this study was to demonstrate the anti-inflammatory and antioxidant effects of Punicalagin®, against pelvic inflammatory disease in rats. Female Sprague Dawley rats (n = 24) were divided into 6 groups (n = 4) as control, PID, prophylactic (low dose and high dose) and therapeutic group (low dose and high dose). PID model was constructed by implanting the rat cervix with mixed microbe (Escherichia Coli and Staphylococcus Aureus) solution. Prophylactic group was gavaged with 3 mg/kg (low dose) and 6 mg/kg (high dose) Punicalagin® daily starting one day before PID induction and therapeutic group was gavaged with 3 mg/kg (low dose) and 6 mg/kg (high dose) Punicalagin® daily starting 1 day after confirmation of PID model. Rats were sacrificed at the end of experiment and samples from upper genital tract were collected for ELISA, antioxidant assay and histopathological examination. According to results, obvious signs of inflammation and oxidative stress including infiltration of neutrophils and significantly raised levels of cytokines, and oxidative stress markers were observed in PID group when compared to control group. Punicalagin® significantly decreased the levels of IL-1β, catalase and lipid peroxidation in both prophylactic and therapeutic groups when compared to PID group. Punicalagin® also decreased the infiltration of leucocytes in uterus of prophylactic and therapeutic group when compared to PID group, as determined by histological examination. On basis of these results, we concluded that Punicalagin® showed anti-inflammatory and antioxidant potential in rat model of pelvic inflammatory disease and could be used as possible therapeutic agent in treatment of PID.

Comparison of clinical effectiveness and subsequent fertility between hysteroscopic resection and vaginal repair in patients with cesarean scar defect: a prospective observational study

OBJECTIVE

To evaluate the clinical effectiveness and pregnancy rate after hysteroscopic resection (HR) and/or vaginal repair (VR) in patients with cesarean scar defect (CSD).

METHODS

This prospective observational study enrolled 191 patients who received CSD surgery in the First affiliated hospital of Sun Yat-sen University between September 2019 to February 2022 (96 in HR and 95 in VR, respectively). Patient follow-up were performed three months after surgery in both groups by transvaginal ultrasound to confirm the presence of fluid in the niche, along with the resolution of prolonged menses at the same time. The primary outcome was the clinical effectiveness between HR and VR, identified by the resolution of prolonged menses.

RESULTS

The rates of niche-fluid disappearance (70.1% vs 60.2%, P = 0.176) and prolonged menses resolution (74.8% vs 80.0%, P = 0.341) were comparable for HR and VR. A subgroup analysis for niche size revealed that HR provides patients with small niche a more favorable rate of menstrual resolution compared to VR (size of niche ≤ 15 mm2, aOR = 3.423, 95% confidence interval [CI] 1.073-10.918), but patients with large niche experience a lower rate of resolution compared to VR (size of niche > 25 mm2, aOR = 0.286, 95% CI 0.087- 0.938). During follow-up, 41 patients who wanted to conceive became pregnant. Kaplan-Meier estimates of the cumulative probability of pregnancy at 12 months and 24 months were 47.1% (95% CI: 34.5%, 58.8%) and 63.8% (95% CI: 52.5%, 72.9%), respectively. The median pregnancy time was 22 months (95% CI: 14.2, 29.8) after VR and 12 months (95% CI: 8.3, 15.7, Gehan-Breslow-Wilcoxon P = 0.021) after HR. Among patients with subsequent infertility, 31.6% achieved pregnancy by unassisted mode and 29.8% by IVF/ICSI. Moreover, among patients with previously failed IVF/ICSI treatment, 60% (12/20) obtained pregnancy, including 71.4% (10/14) after HR and 33.3% (2/6) after VR.

CONCLUSIONS

Hysteroscopic resection is as effective as vaginal repair at relieving symptoms of CSD-associated prolonged menses. Hysteroscopic resection is the modality of choice with an improvement in prolonged menses for small niche, while vaginal might be considered for a large niche. Furthermore, surgical intervention could improve the clinical pregnancy rate of CSD patients. All of these provide evidence for the individualized management of CSD.

Mechanisms of Regeneration and Fibrosis in the Endometrium

The uterine lining (endometrium) regenerates repeatedly over the life span as part of its normal physiology. Substantial portions of the endometrium are shed during childbirth (parturition) and, in some species, menstruation, but the tissue is rapidly rebuilt without scarring, rendering it a powerful model of regeneration in mammals. Nonetheless, following some assaults, including medical procedures and infections, the endometrium fails to regenerate and instead forms scars that may interfere with normal endometrial function and contribute to infertility. Thus, the endometrium provides an exceptional platform to answer a central question of regenerative medicine: Why do some systems regenerate while others scar? Here, we review our current understanding of diverse endometrial disruption events in humans, nonhuman primates, and rodents, and the associated mechanisms of regenerative success and failure. Elucidating the determinants of these disparate repair processes promises insights into fundamental mechanisms of mammalian regeneration with substantial implications for reproductive health.

The efficacy and influence factors analysis of Mifepristone combined with estrogen-progesterone in the treatment of incomplete abortion

To analyze the efficacy and influencing factors of Mifepristone combined with estrogen-progesterone sequential therapy (Femoston) in the treatment of incomplete abortion. This retrospective cohort study included 93 patients with incomplete abortion. All patients took 50 mg of Mifepristone 2 times a day for 5 days and then took Femoston once a day (starting with estradiol tablets/2 mg) for 28 days. Without any indication of intrauterine residue by ultrasonic examination was judged to be effective. According to statistical analysis, this study calculated the effective rate and analyzed its influencing factors. A 2-sided value of P < .05 was considered statistically significant. The total response rate of the treatment regimen was 86.67%. body mass index was a significant influencing factor for treatment outcome (OR 0.818, 95% confidence interval 0.668-0.991, P = .041). For patients with incomplete abortion, Mifepristone combined with estrogen-progesterone sequential therapy has a remarkable therapeutic effect. Patients with a lower body mass index may respond much more significantly to this treatment regimen.

Homogenous subpopulation of human mesenchymal stem cells and their extracellular vesicles restore function of endometrium in an experimental rat model of Asherman syndrome

BACKGROUND

Asherman syndrome (AS), or intrauterine adhesions, is a main cause of infertility in reproductive age women after endometrial injury. Mesenchymal stem cells (MSCs) and their extracellular vesicles (EVs) are promising candidates for therapies that repair damaged endometria. However, concerns about their efficacy are attributed to heterogeneity of the cell populations and EVs. A homogenous population of MSCs and effective EV subpopulation are needed to develop potentially promising therapeutic options in regenerative medicine.

METHODS

AS model was induced by mechanical injury in adult rat uteri. Then, the animals were treated immediately with homogeneous population of human bone marrow-derived clonal MSCs (cMSCs), heterogenous parental MSCs (hMSCs), or cMSCs-derived EV subpopulations (EV20K and EV110K). The animals were sacrificed two weeks post-treatment and uterine horns were collected. The sections were taken, and hematoxylin-eosin was used to examine the repair of endometrial structure. Fibrosis was measured by Masson's trichrome staining and α-SMA and cell proliferation by Ki67 immunostaining. The function of the uteri was explored by the result of mating trial test. Expression changes of TNFα, IL-10, VEGF, and LIF were assayed by ELISA.

RESULTS

Histological analysis indicated fewer glands, thinner endometria, increased fibrotic areas, and decreased proliferation of epithelial and stroma of the uteri in the treated compared with intact and sham-operated animals. However, these parameters improved after transplantation of both types of cMSCs and hMSCs and/or both cryopreserved EVs subpopulations. The cMSCs demonstrated more successful implantation of the embryos in comparison with hMSCs. The tracing of the transplanted cMSCs and EVs showed that they migrated and localized in the uteri. Protein expression analysis results demonstrated downregulation of proinflammatory factor TNFα and upregulation of anti-inflammatory cytokine IL-10, and endometrial receptivity cytokines VEGF and LIF in cMSC- and EV20K-treated animals.

CONCLUSION

Transplantation of MSCs and EVs contributed to endometrial repair and restoration of reproductive function, likely by inhibition of excessive fibrosis and inflammation, enhancement of endometrial cell proliferation, and regulation of molecular markers related to endometrial receptivity. Compared to classical hMSCs, cMSCs were more efficient than hMSCs in restoration of reproductive function. Moreover, EV20K is more cost-effective and feasible for prevention of AS in comparison with conventional EVs (EV110K).

Reproductive outcomes of women with moderate to severe intrauterine adhesions after transcervical resection of adhesion: A systematic review and meta-analysis

BACKGROUND

Intrauterine adhesions (IUA) refers to the adhesion of the inner wall of the uterus, resulting in complete or partial occlusion of the uterine cavity, which causes a series of symptoms. Transcervical resection of adhesion (TCRA) is the standard surgical method for patients with IUA. However, the recurrence rate of women with moderate to severe IUA is high and it has raised a big concern about the reproductive outcomes.

METHODS

We conducted a scoping review by using 4 databases, including Google Scholar, PubMed, Scopus, Embase, and web of science, to retrieve relevant literature from September 1, 2001, to February 1, 2023, and to explore the reproductive outcomes in women with moderate to severe IUA after TCRA treatment. Following defined guidelines, data extraction was carried out by 2 researchers, and the findings were examined by 2 senior academics. The papers were evaluated by 2 reviewers using the inclusion and exclusion criteria. Using a form developed especially for this study, pertinent information was retrieved, including the first author, research design, study duration, age, intervention measurement, pregnancy rate, techniques of conception, and live birth rate. Two researchers conducted a quality assessment to determine any potential bias using the Cochrane technique and the Newcastle-Ottawa scale. RevMan 5.4.1 (The Cochrane Collaboration, London, United Kingdom) was used for data analysis, while I2 was used to evaluate heterogeneity.

RESULTS

In total, this study included 2099 participants. After a detailed systematic review and meta-analyses, the results showed that pregnancy and live birth rates were increased significantly after TCRA, and the risk difference of the pregnancy rate was 1.75 [1.17, 2.62]. Besides, in 2 retrospective studies, the risk difference of live birth rate was 2.26, with a 95% confidence interval of 1.99 to 2.58. Moreover, the menstrual status of women also was improved, and the risk difference of hypermenorrhoea and amenorrhea were -0.28 [-0.37, -0.19] and -0.06 [0.26, 0.13], respectively.

CONCLUSIONS

Taken together, TCRA is the useful strategy for the treatment of moderate to severe IUA to enhance the reproductive outcomes in women.

A comparison of special intrauterine balloons and intrauterine contraceptive devices in the treatment of intrauterine adhesions

PURPOSE

This study aimed to compare the efficacy of a special kind of intrauterine balloon (IUB) and that of an intrauterine contraception device (IUD) for patients with intrauterine adhesions (IUAs) after transcervical resection of adhesion (TCRA).

METHODS

In this retrospective cohort study, after TCRA, 31 patients received a special IUB, and 38 patients received an IUD. The Fisher exact test, logistic regression method, Kaplan-Meier method and Cox proportional hazards regression model were used for statistical analysis. A two-sided value of P < 0.05 was considered statistically significant.

RESULTS

The readhesion rate significantly differed between the IUB group and IUD group, at 15.39% and 54.06%, respectively (P = 0.002). For recurrent moderate IUA, patients in the IUB group had lower scores than patients in the IUD group (P = 0.035). There was a significant difference in the intrauterine pregnancy rate of IUA patients in the IUB group and IUD group after treatment, with rates of 55.56% and 14.29%, respectively (P = 0.015).

CONCLUSION

Patients in the special IUB group had better outcomes than those in the IUD group, which has a certain guiding significance for clinical work.

Injectable self-assembled dual-crosslinked alginate/recombinant collagen-based hydrogel for endometrium regeneration

The disadvantages of mainstream therapies for endometrial injury are difficult to resolve, herein, we suggest an omnibearing improvement strategy by introducing an injectable multifunctional self-assembled dual-crosslinked sodium alginate/recombinant collagen hydrogel. The hydrogel possessed a reversible and dynamic double network based on dynamic covalent bonds and ionic interactions, which also contributed to excellent capability in viscosity and injectability. Moreover, it was also biodegradable with a suitable speed, giving off active ingredients during the degradation process and eventually disappearing completely. In vitro tests exhibited that the hydrogel was biocompatible and able to enhance endometrial stromal cells viability. These features synergistically promoted cell multiplication and maintenance of endometrial hormone homeostasis, which accelerated endometrial matrix regeneration and structural reconstruction after severe injury in vivo. Furthermore, we explored the interrelation between the hydrogel characteristics, endometrial structure, and postoperative uterine recovery, which would benefit deep research on regulation of uterine repair mechanism and optimization of hydrogel materials. The injectable hydrogel could achieve favourable therapeutic efficacy without the need of exogenous hormones or cells, which would be of clinical value in endometrium regeneration.

Chronic endometritis positively correlates with the aggravation of intrauterine adhesions but has limited effects on reproductive prognosis with antibiotic application

OBJECTIVE

To assess the effect of chronic endometritis (CE) diagnosed by CD138 staining on the aggravation of intrauterine adhesions (IUAs), and the reproductive prognosis after transcervical resection of adhesions (TCRA).

METHODS

Sixty-three patients with severe IUAs (group A) and 119 patients with moderate IUAs (group B) were included in this retrospective study. TCRA and endometrial biopsy with CD138 staining were performed. Participants in each group were classified into two subgroups: CE group and NCE group (without CE). Patients were treated with a course of oral antibiotics for 2 weeks after TCRA. Embryo transfer would be performed if patients had embryos after operations.

RESULTS

Increased incidence of CE was found in group A (18/63, 28.57%) compared with group B (18/119, 15.13%) (P = 0.030). No significant differences were found in the comparisons of chemical pregnancy rate, early miscarriage rate, or full-term pregnancy rate between the CE group and NCE group (P > 0.05), in either the subgroup analysis of group A and group B, or the total analysis.

CONCLUSION

CE has a positive correlation with the aggravation of IUAs. CE did not have a negative impact on the reproductive prognosis of patients with moderate or severe IUAs after TCRA followed by antibiotic administration.

Prevalence of and risk factors for chronic endometritis in patients with intrauterine disorders after hysteroscopic surgery

OBJECTIVE

To identify the prevalence of and risk factors for chronic endometritis (CE) in patients with intrauterine disorders and the therapeutic efficacy of hysteroscopic surgery in the treatment of CE without antibiotic therapy.

DESIGN

Prospective cohort study.

SETTING

Hospital specializing in reproductive medicine.

PATIENT(S)

The study population consisted of 350 women with infertility, of whom 337 were recruited, who underwent hysteroscopic surgery between November 2018 and June 2021. Eighty-nine consecutive patients without intrauterine disorders were also recruited as controls.

INTERVENTION(S)

Endometrial samples were collected during the surgery for CD138 immunostaining for the diagnosis of CE. In women diagnosed with CE, endometrial biopsy was performed without antibiotic use in the subsequent menstrual cycle.

MAIN OUTCOME MEASURE(S)

Prevalence of and risk factors for CE in intrauterine disorders and therapeutic effects of hysteroscopic surgery on CE.

RESULT(S)

The prevalence of CE with ≥5 CD138-positive cells in women with no intrauterine disorder and with endometrial polyps, myomas, intrauterine adhesions (IUAs), and septate uterus was 15.7%, 85.7%, 69.0%, 78.9%, and 46.2%, respectively. A multivariate analysis revealed that CE was diagnosed significantly more often in the endometrial polyp (odds ratio, 27.69; 95% confidence interval, 15.01-51.08) and IUA groups (odds ratio, 8.85; 95% confidence interval, 3.26-24.05). The rate of recovery from CE with surgery in women with endometrial polyps, myomas, IUA, and septate uterus was 89.7%, 100%, 92.8%, and 83.3%, respectively.

CONCLUSION(S)

Endometrial polyp and IUA were risk factors for CE. Most CE cases with intrauterine disorders were cured with hysteroscopic surgery without antibiotic therapy, regardless of the type of intrauterine abnormalities.

A LIGHT-HVEM/LTβR axis contributes to the fibrosis of intrauterine adhesion

Intrauterine adhesion (IUA) is a fibrotic disease, with complex and multifactorial process, causing menstrual disorders, pregnancy loss or infertility. LIGHT (also named TNFSF14), mainly expressed by immune cells, has been reported to be associated with tissue fibrosis. However, the features of immunocyte subsets, the expression and roles of LIGHT and its receptor HVEM (herpes virus entry mediator) and LTβR (lymphotoxin beta receptor) in IUA remain largely unknown. Compared with the control group, we observed increased ratios of CD45⁺ cells, neutrophils, T cells, macrophages and decreased natural killer cells proportion, and high LIGHT expression on CD4⁺ T cells and macrophages in IUA endometrium. Further analysis showed there was a positive correlation between upregulated profibrotic factors (e.g., ɑ-smooth muscle actin, transforming growth factor β1) and HVEM in IUA endometrial tissue. More importantly, recombinant human LIGHT protein directly up-regulated the expression of HVEM, LTβR, profibrotic and proinflammatory factors expression in human endometrial stromal cells. These findings reveal abnormal changes of immune cell subsets proportion and the overexpression of LIGHT-HVEM/LTβR axis in IUA endometrium, should contribute to inflammation and fibrosis formation of IUA.

Infectious Inflammatory Processes and the Role of Bioactive Agent Released from Imino-Chitosan Derivatives Experimental and Theoretical Aspects

The paper focuses on the development of a multifractal theoretical model for explaining drug release dynamics (drug release laws and drug release mechanisms of cellular and channel-type) through scale transitions in scale space correlated with experimental data. The mathematical model has been developed for a hydrogel system prepared from chitosan and an antimicrobial aldehyde via covalent imine bonds. The reversible nature of the imine linkage points for a progressive release of the antimicrobial aldehyde is controlled by the reaction equilibrium shifting to the reagents, which in turn is triggered by aldehyde consumption in the inhibition of the microbial growth. The development of the mathematical model considers the release dynamic of the aldehyde in the scale space. Because the release behavior is dictated by the intrinsic properties of the polymer–drug complex system, they were explained in scale space, showing that various drug release dynamics laws can be associated with scale transitions. Moreover, the functionality of a Schrödinger-type differential equation in the same scale space reveals drug release mechanisms of channels and cellular types. These mechanisms are conditioned by the intensity of the polymer–drug interactions. It was demonstrated that the proposed mathematical model confirmed a prolonged release of the aldehyde, respecting the trend established by in vitro release experiments. At the same time, the properties of the hydrogel recommend its application in patients with intrauterine adhesions (IUAs) complicated by chronic endometritis as an alternative to the traditional antibiotics or antifungals.

Increased serum LOXL2 concentration in pelvic inflammatory disease with pelvic adhesion

Background

Lysyl oxidase-like 2 (LOXL2) belongs to a family of the LOX secretory enzyme, which involves the cross-linkage of extracellular matrix (ECM) proteins. Here, we aimed to analyze the correlation between serum LOXL2 and pelvic adhesion in chronic pelvic inflammatory disease (PID).

Methods

A total of 143 patients with PID and 130 healthy controls were included in this study. The serum levels of LOXL2 were measured using enzyme-linked immunosorbent assay (ELISA) kits. The patients were divided into non-adhesion group (102 cases) and adhesion group (41 cases).

Results

It was found that the serum level of LOXL2 expression was elevated in PID patients compared with healthy controls, and was elevated in PID patients with pelvic adhesion compared to patients without adhesion. In all PID patients, serum LOXL2 level was positively correlated with matrix metalloproteinases-9 (MMP-9), transforming growth factor-β (TGF-β1), whole blood viscosity (WBV) at low shear rate (LSR), WBV at high shear rate (HSR), and hematocrit (HcT). Multivariate logistic regression analysis showed that serum LOXL2 level was an independent risk factor for pelvic adhesion in PID patients (OR = 1.058; 95% CI = 1.030–1.086, P < 0.001).

Conclusions

Serum LOXL2 level not only predicts the presence of PID, but serum LOXL2 concentration is also associated with the presence of pelvic adhesions.

Reproductive outcomes and reproductive tract microbiota shift in women with moderate-to-severe intrauterine adhesions following 30-day post-hysteroscopic placement of balloon stents or intrauterine contraceptive devices: A randomized controlled trial

BACKGROUND

Intrauterine adhesions (IUA) develop in up to 20% of women with a history of abortion. After hysteroscopic adhesiolysis, balloon stents are usually placed for seven days to prevent recurrence. The efficacy of prolonged use (30 days) of balloon stents has not been determined.

METHODS

The trial was conducted from June 2019 to March 2021. Ninety-one patients who underwent hysteroscopic adhesiolysis for moderate or severe IUA were randomized to receive a 30-day placement of a balloon stent (n = 44) or an intrauterine device (IUD) (n = 47). The primary outcomes were the ongoing pregnancy and miscarriage rates assessed at 15-19 months. The secondary outcomes were the recurrence of IUA and the American Fertility Society (AFS) intrauterine adhesion scores at the first and second hysteroscopies, the diagnosis of new chronic endometritis at the second-look hysteroscopy, and the vaginal/uterine microbiome assessed using 16S rRNA sequencing. The trial was registered at Chinese Clinical Trial Registry (ChiCTR1900023306).

FINDINGS

The ongoing pregnancy rates (balloon 56·4% versus IUD 57·1%) and miscarriage rates (balloon 10·3% versus IUD 22·9%) were not significantly different between the groups. No differences in the recurrence of IUA, reduction of AFS scores, or new endometritis rates were detected. The bacterial load in the uterus and vagina increased in the IUD group but not in the balloon group.

INTERPRETATION

Balloon placement has a similar effect on ongoing pregnancy rates as intrauterine device (IUD) placement. Patients who underwent balloon placement had a lower miscarriage rate, although the difference was not significant. There were no differences in the recurrence rate of IUA, reduction of American Fertility Society scores, or rate of new chronic endometritis. The balloon stent has less effects on the uterine microbiota.

FUNDING

National Natural Science Foundation of China (81802593).

Making More Womb: Clinical Perspectives Supporting the Development and Utilization of Mesenchymal Stem Cell Therapy for Endometrial Regeneration and Infertility

The uterus is a homeostatic organ, unwavering in the setting of monthly endometrial turnover, placental invasion, and parturition. In response to ovarian steroid hormones, the endometrium autologously prepares for embryo implantation and in its absence will shed and regenerate. Dysfunctional endometrial repair and regeneration may present clinically with infertility and abnormal menses. Asherman's syndrome is characterized by intrauterine adhesions and atrophic endometrium, which often impacts fertility. Clinical management of infertility associated with abnormal endometrium represents a significant challenge. Endometrial mesenchymal stem cells (MSC) occupy a perivascular niche and contain regenerative and immunomodulatory properties. Given these characteristics, mesenchymal stem cells of endometrial and non-endometrial origin (bone marrow, adipose, placental) have been investigated for therapeutic purposes. Local administration of human MSC in animal models of endometrial injury reduces collagen deposition, improves angiogenesis, decreases inflammation, and improves fertility. Small clinical studies of autologous MSC administration in infertile women with Asherman's Syndrome suggested their potential to restore endometrial function as evidenced by increased endometrial thickness, decreased adhesions, and fertility. The objective of this review is to highlight translational and clinical studies investigating the use of MSC for endometrial dysfunction and infertility and to summarize the current state of the art in this promising area.

Chronic endometritis: A prevalent yet poorly understood entity

OBJECTIVE

To examine the prevalent understanding of and management approaches to chronic endometritis among obstetricians/gynecologists.

METHODS

In a cross-sectional observational study, 262 members of national and international professional obstetrician/gynecologist societies were surveyed via anonymous electronic survey that investigated knowledge of the pathophysiology, diagnostic criteria, clinical implications, and treatment strategies for chronic endometritis. Statistical analyses of results were performed using Fisher's exact tests, chi square tests and odds ratios with 95% confidence intervals. A two-sided P < 0.05 was deemed statistically significant.

RESULTS

Responses identified a concerning spectrum of deficiencies in the understanding of the pathophysiology of chronic endometritis, in awareness of clinical presentation of chronic endometritis, and in the understanding of methodology/ies that allow diagnosis of chronic endometritis. Heterogeneities in management approaches to chronic endometritis were apparent.

CONCLUSION

Our findings underscore a need for targeted efforts to gain clarity on chronic endometritis and to establish evidence-based consensus for good clinical practice. In the absence of a clear understanding of chronic endometritis diagnosis, we posit that the prevalent inconsistencies are likely inflicting unquantified and underappreciated burdens on patients and healthcare systems. We propose consideration for a task force to examine existing literature and create standards for good practice for a prevalent condition.

Impact of oral antibiotic treatment for chronic endometritis on pregnancy outcomes in the following frozen-thawed embryo transfer cycles of infertile women: a cohort study of 640 embryo transfer cycles

OBJECTIVE

To investigate the therapeutic effect of antibiotic treatment on pregnancy outcomes in the following frozen-thawed embryo transfer cycles of infertile women.

DESIGN

Retrospective study.

SETTING

University assisted reproduction unit.

PATIENT(S)

A total of 640 women were included. Among them, the number of CD138+ cells per high-power field (CD138+/HPF) in the endometrium at the first evaluation was 0 in 88 women; 315 women had 1-4 CD138+/HPF and the remaining 237 had ≥5 CD138+/HPF. Finally, 26 of 237 women had persistent chronic endometritis (PCE) diagnosed.

INTERVENTION(S)

Hysteroscopy and endometrial biopsy were performed in the proliferative phase. After antibiotic treatment, endometrial biopsy samples were collected again.

MAIN OUTCOME MEASURE(S)

Live birth rate.

RESULT(S)

No significant difference in pregnancy outcomes was found between women with CD138+/HPF = 0 and those with CD138+/HPF 1-4. The cure rate was 89.0% in women with CD138+/HPF ≥5 after treatment. The implantation rate (51.6% vs. 32.3%, relative risk [RR] 2.23, 95% confidence interval [CI] 1.07-4.66), clinical pregnancy rate (65.7% vs. 42.3%, RR 2.62, 95% CI 1.17-5.86), live birth rate (52.1% vs. 30.7%, RR 2.45, 95% CI 1.04-5.76), and cumulative live birth rate (64.2% vs. 38.5%, RR 2.88, 95% CI 1.27-6.51) were all significantly higher in women with CD138+/HPF ≤4 than in women with PCE.

CONCLUSION(S)

CD138+/HPF ≤4 in the endometrium had no negative impact on pregnancy outcomes. Antibiotic treatment was an effective way to improve the reproductive outcomes of women with CD138+/HPF ≥5. PCE was associated with poorer pregnancy outcomes.

Induction of the epithelial-mesenchymal transition in the endometrium by chronic endometritis in infertile patients

Background

The purpose of the present study was to evaluate the relationship between chronic endometritis and the epithelial-mesenchymal transition in the endometrium of infertile patients in the implantation phase.

Methods

Endometrial biopsy specimens from 66 infertility patients were analyzed. The presence of chronic endometritis was investigated by immunostaining for CD138. Immunohistochemical staining for E-cadherin, N-cadherin, Slug, and Snail was performed, and the expression profiles were statistically analyzed according to the presence of chronic endometritis. When the loss of E-cadherin expression and/or the positive expression of N-cadherin was detected, the specimen was considered epithelial-mesenchymal transition-positive. Epithelial-mesenchymal transition-positive cases were also statistically analyzed according to the presence of chronic endometritis. The characteristics of the patients in the epithelial-mesenchymal transition-positive and epithelial-mesenchymal transition-negative groups were compared. The association between variables, including age, body mass index, gravidity, parity, and each causative factor of infertility and epithelial-mesenchymal transition positivity was analyzed.

Results

The rates of the loss of E-cadherin expression, the gain of N-cadherin and epithelial-mesenchymal transition positivity were significantly higher in chronic endometritis patients. The expression of Slug, cytoplasmic Snail, and nuclear Snail was also detected at significantly higher rates in chronic endometritis patients. Chronic endometritis were related to the epithelial-mesenchymal transition.

Conclusion

The epithelial-mesenchymal transition was frequently detected in the endometrium in infertile patients with chronic endometritis. Since the epithelial-mesenchymal transition is associated with chronic endometritis, the epithelial-mesenchymal transition appears to be involved in the alteration of mechanisms of implantation.

Impact of chronic endometritis in infertility: a SWOT analysis

Chronic endometritis is a pathology often associated with reproductive failure, but there are still no clear recommendations on whether its inclusion in the initial study of infertile couples is necessary. In this discussion paper, based on a SWOT (Strengths, Weaknesses, Opportunities, Threats) analysis, the different aspects of the repercussions of chronic endometritis in fertility are evaluated. To avoid possible subjectivity in the analysis and results of this study, the researchers followed the Oxford criteria for the evaluation of evidence. The results from the evaluation of the reviewed literature seem to indicate that, pending new evidence, it would be advisable not to include chronic endometritis in the initial baseline study before assisted reproduction in order not to delay other assisted reproduction treatments. However, it would be advisable in cases of repetitive implantation failure and pregnancy loss after having undergone IVF with viable embryos and before continuing with costly reproductive processes, since results could be improved. The development of randomized studies assessing the impact of antibiotic treatment as a possible therapeutic option in infertile women with chronic endometritis, as well as the possible impact on endometrial microbiota and receptivity/implantation, would allow for the establishment of more precise clinical guidelines in this regard.

3D Bioprinting a human iPSC-derived MSC-loaded scaffold for repair of the uterine endometrium

Common events in the clinic, such as uterine curettage or inflammation, may lead to irreversible endometrial damage, often resulting in infertility in women of childbearing age. Currently, tissue engineering has the potential to achieve tissue manipulation, regeneration, and growth, but personalization and precision remain challenges. The application of "3D cell printing" is more in line with the clinical requirements of tissue repair. In this study, a porous grid-type human induced pluripotent stem cell-derived mesenchymal stem cell (hiMSC)-loaded hydrogel scaffold was constructed using a 3D bioprinting device. The 3D-printed hydrogel scaffold provided a permissive in vitro living environment for hiMSCs and significantly increased the survival duration of transplanted hiMSCs when compared with hiMSCs administered locally in vivo. Using an endometrial injury model, we found that hiMSC transplantation can cause early host immune responses (the serological immune response continued for more than 1 month, and the local immune response continued for approximately 1 week). Compared with the sham group, although the regenerative endometrium failed to show full restoration of the normal structure and function of the lining, implantation of the 3D-printed hiMSC-loaded scaffold not only promoted the recovery of the endometrial histomorphology (endometrial tissue and gland regeneration) and the regeneration of endometrial cells (stromal cells and epithelial cells) and endothelial cells but also improved endometrial receptivity functional indicators, namely, pinopode formation and leukemia inhibitory factor and αvβ3 expression, which partly restored the embryo implantation and pregnancy maintenance functions of the injured endometrium. These indicators were significantly better in the 3D-printed hiMSC-loaded scaffold group than in the unrepaired (empty) group, the hiMSCs alone group and the 3D scaffold group, and the empty group showed the worst repair results. Our study confirm that the 3D-printed hiMSC-loaded hydrogel scaffold may be a promising material for endometrial repair.

Transplantation of Human Amnion Epithelial Cells Improves Endometrial Regeneration in Rat Model of Intrauterine Adhesions

Intrauterine adhesions (IUAs) are characterized by the injury of endometrium due to curettage and/or endometritis. The loss of functional endometrium in uterine cavity usually results in hypomenorrhea, amenorrhea, infertility, and/or recurrent pregnancy loss. Recently, stem cell transplantation has been applied to promote the endometrial regeneration. Human amnion epithelial cells (hAECs) have been shown to have stem cell characteristics. In this study, we found that PKH26-labeled hAECs were mainly distributed in the basal layer of endometrium after transplantation, and hAEC transplantation, including uterine injection and tail vein injection, could increase pregnancy rate and the number of embryos in rat model of IUAs. Moreover, hAEC transplantation was demonstrated to increase the endometrial thickness, promote the proliferation of glands and blood vessels, and decrease fibrotic areas in the endometrium. The immunohistochemical and quantitative polymerase chain reaction analysis showed the upregulated expression of growth factors, such as basic fibroblast growth factor (bFGF), vascular endothelial growth factor (VEGF), insulin-like growth factor-1 (IGF-1) after hAEC transplantation; and the downregulated expression of collagen type I alpha 1 (COL1A1), tissue inhibitor of metalloproteinase-1 (TIMP-1), and transforming growth factor-β (TGF-β), all of which are associated with the extracellular matrix (ECM) deposition after hAEC transplantation. The mRNA sequencing indicated that platelet-derived growth factor-C (PDGF-C), thrombospondin-1 (THBS1), connective tissue growth factor (CTGF), Wnt5a, and Snai2 were significantly modulated in treatment groups. These results indicate that hAEC transplantation promotes endometrial regeneration and the restoration of fertility in rat model of IUAs.

Chronic endometritis and reproductive failure: Role of syndecan-1

Chronic endometritis (CE) is an unusual inflammatory condition characterized by endometrial plasmacyte infiltration. It has a high prevalence in women with reproductive failure. Because of its characteristic localization patterns and molecular functions, syndecan-1 has been identified as a biomarker of plasmacyte, and syndecan-1 immunohistochemistry (IHC) becomes the most dependable diagnostic method for CE. In this review, we discuss the association between CE and reproductive failure, the clinicopathological characterization of CE, the function and expression of syndecan-1, the progress of syndecan-1 IHC in the diagnosis of CE, and the prediction of reproductive outcome.

Exosomes Derived from Adipose Mesenchymal Stem Cells Restore Functional Endometrium in a Rat Model of Intrauterine Adhesions

Intrauterine adhesion (IUA) caused by endometrial injury is one of the important causes of infertility in women of reproductive age and requires advanced treatment strategies. Increasing evidence suggests that the therapeutic effects of mesenchymal stem cells (MSC) mainly depend on their capacity to secrete paracrine factors and are mediated by MSC-derived exosomes. This study aimed to identify exosomes derived from adipose-derived mesenchymal stem cells (ADSC-exo) and explore the therapeutic potential in IUA rat models. ADSC-exo exhibited classic cup-shaped morphology with a positive expression of Alix and CD63 and were mainly concentrated at 109.5 nm. In IUA model, treatment with ADSC-exo maintained normal uterine structure, promoted endometrial regeneration and collagen remodeling, and enhanced the expression of integrin-β3, LIF, and VEGF. An improved receptivity of the regenerated endometrium was confirmed. Our findings demonstrated that ADSC-exo promoted endometrial regeneration and fertility restoration. It suggested that topical administration of ADSC-exo in uterus could be a promising strategy for patients suffering severe intrauterine adhesions and infertility.