Treating patients with "thin" endometrium - an ongoing challenge

Infertility treatment using polysaccharides-based hydrogels: new strategies in tissue engineering and regenerative medicine

Infertility is a primary health issue affecting about 15% of couples of reproductive ages worldwide, leading to physical, mental, and social challenges. Advances in nanobiotechnology and regenerative medicine are opening new therapeutic horizons for infertility by developing polysaccharide-based nanostructured biomaterials. This review explores the role of tissue engineering and regenerative medicine in infertility treatment, explicitly focusing on the promising potential of polysaccharide-based hydrogels. In this context, using these biomaterials offers unique advantages, including biodegradability, biocompatibility, and the ability to mimic the natural endometrial microenvironment, making them highly effective for applications in endometrial regeneration, ovarian tissue engineering, spermatogenesis support, and controlled drug delivery. This review discusses the various properties and uses of polysaccharide-based hydrogels, like alginate, hyaluronic acid, and chitosan, in helping to restore reproductive function. While these materials hold great promise, some notable challenges to their clinical use include issues like rapid degradation, mechanical instability, and potential immune reactions. Future research should focus on developing hybrid hydrogels, investigating advanced fabrication techniques, and testing these materials in clinical settings. By combining findings from recent studies, this review aims to provide a solid foundation for researchers and clinicians looking to discover new and effective strategies for treating infertility, ultimately connecting research efforts with practical applications in healthcare.

The effect of endometrial PRP on fertility outcomes in women with implantation failure or thin endometrium

OBJECTIVE

To evaluate the effect of intrauterine platelet-rich plasma (PRP) treatment on frozen-thawed embryo transfer (FET) cycles in patients with recurrent implantation failure.

MATERIALS AND METHODS

The study group consisted of 150 patients. The patients were grouped only as those with thin endometria, those with recurrent implantation failure (RIF), and those with both thin endometria and RIF. All participants underwent frozen embryo transfer. The control group consisted of a total of 150 patients who had normal endometrial thickness and did not have a history of RIF and who presented to the clinic due to unexplained infertility. The rates of biochemical pregnancy, clinical pregnancy, miscarriage and live birth were compared among the groups in terms of fertility outcomes.

RESULTS

In 150 patients with a thin endometrium or a history of RIF who underwent PRP, the endometrial thickness was significantly greater than the pre-PRP endometrial thickness, and this value was found to be statistically significant (7.38 mm vs. 7.96 mm, p < 0.001). In the thin endometrium group, there was also a statistically significant difference between the endometrial thickness measured before and after PRP (5.85 mm vs 6.65 mm, p < 0.001). The rate of not achieving pregnancy in the RIF group without PRP was found to be significantly greater than that in the control group (53.1% vs 28.7%, p < 0.05). There was no significant difference in pregnancy rates between the PRP groups. Morever, no statistically significant relationship was found between pregnancy status and whether or not PRP was performed in RIF patients (p value > 0.05). Overall, although there was an increase in clinical pregnancy and live birth rates in the PRP group compared with the control group, this difference did not reach statistical significance.

CONCLUSION

In patients suffering from a thin endometrium or RIF, although endometrial PRP increases endometrial thickness, it does not significantly improve fertility outcomes.

Long-term therapeutic effects of allogeneic mesenchymal stem cell transplantation for intrauterine adhesions

BACKGROUND

Intrauterine adhesion (IUA), resulting from uterine trauma, is one of the major causes of female infertility. Previous studies have demonstrated that endometrial mesenchymal stem cells (eMSC) have therapeutic effects on IUA through cellular secretions. It is particularly true for most of the pre-clinical experiments performed on multiple animal models, as human-derived eMSC cannot maintain long-term engraftment in animals. Whether tissue-specific MSCs from allogeneic origin can engraft and exert long-term therapeutic efficacy has yet to be thoroughly explored.

METHODS

We established a rat IUA model to study the long-term engraftment and therapeutic effects of eMSC derived from humans and rats. Human and rat eMSC were isolated and verified by the expression of cell surface markers and the ability to differentiate into osteoblasts, adipocytes, and chondrocytes. The cells were then labeled by green fluorescence proteins (GFP) and transplanted to the rat uterus ex vivo and in vivo. The engraftment was investigated by the expression of GFP at different days after transplantation. Assessed the therapeutic effects by examining the endometrial thickness, the number of glands, and the pregnancy outcome. Significantly, we conducted a thorough assessment of the local cellular immune response following both xenograft and allograft transplantation.

RESULTS

H-eMSC were eliminated by rats' immune systems within three days after transplantation. In constrast, R-eMSC successfully engrafted and persisted in rat tissue for over ten days. Notably, R-eMSC significantly improved the pregnancy rate by enhancing endometrial thickness and increasing the number of glands, while also reducing fibrosis in rat IUA models. Additionally, the immune response to R-eMSC was generally less aggressive compared to that of xenogeneic MSCs.

CONCLUSIONS

Tissue-specific MSCs from the allogeneic origin can integrate into the repaired tissue and exert long-term therapeutic efficacy in the model of IUA. This study indicates that in addition to secreting therapeutic factors short-time, tissue-specific MSCs may engraft and participate in long-time tissue repair and regeneration.

Association between first-trimester subchorionic hematoma and pregnancy loss before 20 weeks of gestation in singleton pregnancies

To evaluate the association between a first-trimester subchorionic hematoma (SCH) and pregnancy loss before 20 weeks of gestation in singleton pregnancies. We conducted a retrospective cohort study of singleton pregnancies from January to December 2021. All patients had routine first-trimester ultrasound scans and were followed up for pregnancy outcomes. We compared pregnancy loss rates before 20 weeks in women with and without SCH and analyzed risk factors using logistic regression. Out of 1,144 singleton pregnancies, 559 (48.9%) had SCH. Women with SCH had higher rates of vaginal bleeding (38.1 vs. 23.2%, P < 0.001). SCH was independently associated with miscarriage before 20 weeks (adjusted OR 1.94, 95% CI 1.19-3.15). Earlier SCH diagnosis increased miscarriage risk (adjusted OR 2.71 for diagnosis before 7 weeks, 95% CI 1.45-5.07). SCH size was not linked to pregnancy loss, but "large" SCH increased placental abruption risk (adjusted OR 5.03, 95% CI 1.20-21.11). Dydrogesterone use appeared protective against miscarriage (adjusted OR 0.28, 95% CI 0.15-0.52). First-trimester SCH is associated with an increased risk of miscarriage before 20 weeks. Large SCHs increase the risk of placental abruption, while dydrogesterone use may reduce miscarriage risk.

Network meta-analysis of four common immunomodulatory therapies for the treatment of patients with thin endometrium

OBEJECTIVE

To compare the effectiveness of endometrial receptivity and pregnancy outcomes of four common immunomodulatory therapies for patients with thin endometrium.

METHOD

This systematic review and network meta-analysis using a literature search up to January 2024, to identify relevant trials comparing endometrial receptivity and pregnancy outcomes of human chorionic gonadotropin (hCG), platelet-rich plasma (PRP), infusion of granulocyte colony-stimulating factor (IG-CSF), and peripheral blood mononuclear cell (PBMC) for patients with thin endometrium. We used surface under the cumulative ranking (SUCRA) to ranked four common immunomodulatory therapies on endometrium thickness, implantation rate (IR), clinical pregnancy rate (CPR), and live birth rate (LBR). RoB2 and ROBINS-I were used to assess the certainty of evidence.

RESULTS

The pooled results of 22 studies showed that hCG (mean difference [MD]: 3.05, 95% confidence interval [CI]: 1.46-4.64) and PRP (MD: 0.98, 95% CI: 0.20-1.76) significantly increase endometrium thickness. The hCG was the best among the IG-CSF (MD = -2.56, 95% CI = -4.30 to -0.82), PBMC (MD = -2.75, 95% CI = -5.49 to -0.01), and PRP (MD = -2.07, 95% CI = -3.84 to -0.30) in increasing endometrium thickness. However, IG-CSF and PRP significantly improved IR (IG-CSF: risk ratio (RR; IG-CSF: RR = 1.33, 95% CI = 1.06-1.67; PRP: RR = 1.63, 95% CI = 1.19-2.23), and LBR (IG-CSF: RR = 1.53, 95% CI = 1.16-2.02; PRP: RR = 1.59, 95% CI = 1.08-2.36).

CONCLUSIONS

Available evidence reveals that hCG and subcutaneous or intrauterine CSF (SG-CSF) may be the best treatment options for current thin endometrium patients. However, future high-quality and large-scale studies are necessary to validate our findings.

Evaluation of the effect of an amniotic membrane derived bio-nano product (LifeCell) on human endometrial cells proliferation and gene expression: An in-vitro study

OBJECTIVE

Successful assisted reproductive technology (ART) requires a receptive endometrium with appropriate thickness and the presence of specific cytokines, chemokines, and growth factors. Despite advancements in ART, the success rates remain suboptimal, particularly in individuals with thin endometrium resistant to treatment. In this study, we evaluated the potential effects of LifeCell, a product of BioNano Technology, on the growth, development, and acceptance of endometrial cells.

STUDY DESIGN

We cultured endometrial cells in a defined medium with different concentrations of LifeCell and examined cell growth, development, and the expression of genes involved in endometrial receptivity.

RESULTS

Co-culture of primary human endometrial cells with 5 % Life cell solution significantly stimulated the endometrial cell growth, development and receptivity genes expression. The expression levels of FGF2 and CSF in the 72 h co-cultured were significantly increased compared with other groups (P < 0.01). HOXA10 and LIF significantly increased in the 72 h co-cultured compared with 24 h co-cultured and control groups but had no significant level compared with 48 h cocultured. HOXA10 significantly increased in the 48 h cocultured compared with control group. IL-6 and Hb-EGF increased in the 48 h co-cultured compared to other groups but had no significant level. VEGF increased in the treated groups compared to control but had no significant level. The expression of OPN, unlike the other genes, decreased in the treated group compared to the control, which was not significant.

CONCLUSIONS

These findings suggest that LifeCell may be a potential option for patients with treatment-resistant thin endometrium in cases of infertility.

Decoction of Yougui Wan combined with Wuzi Yanzong Wan ameliorates thin endometrium in a mouse model

BACKGROUND

This study aimed to determine the effect and mechanism of the Decoction of Yougui Wan combined with Wuzi Yanzong Wan (DYWWYW), a traditional Chinese herbal formula, in a mouse model with thin endometrium induced by 95% ethanol.

METHODS

Thin endometrium mice were treated with progynova (0.002 mg) as well as a low and high dose of DYWWYW (0.05 and 0.5 mL DYWWYW, respectively, diluted in 2 mL normal saline). Western blotting and qRT-PCR analyses were performed to determine the protein and mRNA expression levels, respectively, of integrin αγβ3 and leukaemia inhibitor factor (LIF) in uterus tissues. Serum oestradiol and progesterone concentrations were determined via ELISA. The remaining thin endometrium mice were mated with male mice, and the number of embryos implanted in the different groups was calculated.

RESULTS

A high dose of DYWWYW effectively ameliorated the injury of endometrium caused by 95% ethanol. The levels of oestradiol, progesterone, αγβ3 and LIF in thin endometrium mice treated with a high dose of DYWWYW were also significantly elevated. Additionally, a high dose of DYWWYW remarkably increased the number of embryo implantations in mice with thin endometrium.

CONCLUSION

DYWWYW has improvement effects on thin endometrium by elevating the levels of endogenous oestradiol, progesterone, αγβ3, and LIF in a mouse model.

Strategies and Challenges of Mesenchymal Stem Cells-Derived Extracellular Vesicles in Infertility

Having genetically related offspring remains an unattainable dream for couples with reproductive failure. Mesenchymal stem cells (MSCs) are multipotent stromal cells derived from various human tissues and organs. As critical paracrine effectors of MSCs, extracellular vesicles (EVs) can carry and deliver bioactive content, thereby participating in intercellular communication and determining cell fate. Mesenchymal stem cell-derived extracellular vesicles (MSC-EVs) have shown promising therapeutic effects, including repairing injured endometria, restoration of ovarian functions, and improving sperm quantity, morphology, and motility, owing to their regenerative potential, abundant sources, high proliferation rates, low immunogenicity, and lack of ethical issues. However, limited knowledge on purification and isolation of MSC-EVs, therapeutic effects, and unpredictable safety have caused challenges in overcoming female and male infertility. To overcome them, future studies should focus on modification/engineering of MSC-EVs with therapeutic biomolecules and combining attractive biomaterials and MSC-EVs. This review highlights the latest studies on MSC-EVs therapies in infertility and the major challenges that must be overcome before clinical translation.

GM-CSF improves endometrial receptivity in a thin endometrium rat model by upregulating HOXA10

Endometrial receptivity is a prerequisite for the success of assisted reproduction. Patients with a consistently thin endometrium frequently fail to conceive, owing to low endometrial receptivity, and there are currently very few therapeutic options available. Our previous study demonstrated that intrauterine granulocyte-macrophage colony-stimulating factor (GM-CSF) administration resulted in a significant improvement in clinical pregnancy and implantation rates and was an effective means of increasing endometrial thickness on the day of embryo transfer in patients with thin endometrium. In order to explore the underlying process, an animal model with a thin endometrium was constructed, the homeobox A10 gene (HOXA10) was downregulated, and an inhibitor of the mitogen-activated protein kinase/extracellular signal-regulated kinase pathway (MAPK/ERK) was employed. Our findings strongly suggest a marked decrease in GM-CSF levels in the thin endometrial rat model, and the suppression of HOXA10 impeded the therapeutic efficacy of GM-CSF in this model. Moreover, we showed that GM-CSF significantly increases endometrial receptivity in the rat model and upregulates HOXA10 via the MAPK/ERK pathway. Our data provide new molecular insights into the mechanisms underlying formation of a thin endometrium and highlight a novel, potential clinical treatment strategy as well as directions for further research.

Yueliang Yin Ameliorates Endometrial Receptivity in Mice with Embryo Implantation Failure by Reducing Pyroptosis and Activating BDNF/TrkB Pathway

SCOPE

Endometrial receptivity plays a vital role in embryonic implantation. Yueliang Yin is a marketed solid drink in China, also known as Bushen Cuyun Recipe (BCR), that is, assumed to have a therapeutic effect on infertility by improving endometrial receptivity. This study investigates the effects and mechanisms of BCR in protecting the endometrium.

METHODS AND RESULTS

Mice with mifepristone-induced embryo implantation failure that exhibited a decreased implantation sites number, thinner endometrium, reduced endometrial glands number, and poor pinopode expression levels are treated with BCR, and these mentioned conditions significantly improves afterward. Molecular docking shows that the main active components kaempferol, quercetin, and hesperetin of BCR stably bound to gasdermin D (GSDMD). Experimental results demonstrate that levels of GSDMD, cleaved caspase-1 and leucine-rich repeat, and pyrin domain-containing 3 and IL-1β levels in model mice are significantly decreased and expressions of brain-derived neurotrophic factor (BDNF) and tyrosine protein kinase B (TrkB) expression levels are significantly elevated after BCR treatments, and that the DNA damage is significantly reversed in BCR-treated mice.

CONCLUSIONS

BCR is potent and effective in ameliorating endometrial receptivity. The potential mechanisms of BCR on endometrial receptivity may mediate by activating BDNF/TrkB pathway activation and protecting endometrial cells' protection against pyroptosis.

Involvement of small leucine-rich proteoglycans and telocytes in thin and thick human endometrium: immunohistochemical and ultrastructural examination

Thin endometrium, defined as an endometrial thickness of less than 7 mm during the late follicular phase, is a common cause of frequent cancelation of embryo transfers or recurrent implantation failure during assisted reproductive treatment. Small proteoglycans regulate intracellular signaling cascades by bridging other matrix molecules and tissue elements, affecting cell proliferation, adhesion, migration, and cytokine concentration. The aim of the study is to investigate the role of small leucine-rich proteoglycans in the pathogenesis of thin and thick human endometrium and their differences from normal endometrium in terms of fine structure properties. Normal, thin, and thick endometrial samples were collected, and small leucine-rich proteoglycans (SLRPs), decorin, lumican, biglycan, and fibromodulin immunoreactivities were comparatively analyzed immunohistochemically. The data were compared statistically. Moreover, ultrastructural differences among the groups were evaluated by transmission electron microscopy. The immunoreactivities of decorin, lumican, and biglycan were higher in the thin endometrial glandular epithelium and stroma compared to the normal and thick endometrium (p < .001). Fibromodulin immunoreactivity was also higher in the thin endometrial glandular epithelium than in the normal and thick endometrium (p < .001). However, there was no statistical difference in the stroma among the groups. Ultrastructural features were not profoundly different among cases. Telocytes, however, were not seen in the thin endometrium in contrast to normal and thin endometrial tissues. These findings suggest a possible role of changes in proteoglycan levels in the pathogenesis of thin endometrium.

MenSCs Transplantation Improve the Viability of Injured Endometrial Cells Through Activating PI3K/Akt Pathway

Endometrial injury is one of the leading causes of female infertility and is caused by intrauterine surgery, endometrial infection, repeated abortion, or genital tuberculosis. Currently, there is little effective treatment to restore the fertility of patients with severe intrauterine adhesions and thin endometrium. Recent studies have confirmed the promising therapeutic effects of mesenchymal stem cell transplantation on various diseases with definite tissue injury. The aim of this study is to investigate the improvements of menstrual blood-derived endometrial stem cells (MenSCs) transplantation on functional restoration in the endometrium of mouse model. Therefore, ethanol-induced endometrial injury mouse models were randomly divided into two groups: the PBS-treated group, and the MenSCs-treated group. As expected, the endometrial thickness and gland number in the endometrium of MenSCs-treated mice were significantly improved compared to those of PBS-treated mice (P < 0.05), and fibrosis levels were significantly reduced (P < 0.05). Subsequent results revealed that MenSCs treatment significantly promoted angiogenesis in the injured endometrium. Simultaneously, MenSCs enhance the proliferation and antiapoptotic capacity of endometrial cells, which is likely contributed by activating the PI3K/Akt signaling pathway. Further tests also confirmed the chemotaxis of GFP-labeled MenSCs towards the injured uterus. Consequently, MenSCs treatment significantly improved the pregnant mice and the number of embryos in pregnant mice. This study confirmed the superior improvements of MenSCs transplantation on the injured endometrium and uncovered the potential therapeutic mechanism, which provides a promising alternative for patients with serious endometrial injury.

Clinical efficacy of hysteroscopic adhesiolysis combined with periodic balloon dilation for intrauterine adhesion in IVF treatment

Background

Intrauterine adhesions (IUA), arising from diverse etiological factors, pose a significant threat to female fertility, particularly during in vitro fertilization (IVF) treatment.

Objective

To assess the effectiveness of hysteroscopic adhesiolysis (HA) combined with periodic balloon dilation in treating IUA and its impact on reproductive outcomes in women undergoing IVF treatment.

Methods

A total of 234 patients diagnosed with IUA were included in this study. The IUA women were categorized into three subgroups based on the severity of adhesion. All IUA patients underwent HA separation followed by periodic balloon dilation along with hormone replacement therapy (HRT). Frozen embryo transfer was performed post-treatment, and a comparative analysis of the general characteristics and clinical outcomes among the subgroups was conducted. The control group consisted of patients who underwent their first embryo transfer of HRT cycle without any uterine abnormalities, as assessed by the propensity score matching (PSM). The clinical outcomes of IUA group and control group were compared. Multivariate logistic regression analyses were employed to investigate the risk factors associated with live birth.

Results

① The endometrial thickness was significantly increased post-operation compared to pre-operation in all three IUA subgroups (all P <0.001), with the most pronounced change observed in the severe IUA group. After treatment, normal uterine cavity was restored in 218 women (93.16%). ② The overall clinical pregnancy rate was 49.57% (116/234) and live birth rate was 29.91% (70/234). The clinical outcomes were similar among the three subgroups after first embryo transfer (all P>0.05). Multivariate logistic regression analyses revealed that age (aOR 0.878, 95% CI 0.817~0.944, P=0.001) and endometrial thickness after treatment (aOR 1.292, 95% CI 1.046~1.597, P=0.018) were the two significant risk factors for live birth rate. ③ Following the process of matching, a total of 114 patients were successfully enrolled in the control group. The baselines and the clinical outcomes were all comparable between the IUA group and control group (all P>0.05).

Conclusion

The combination of HA and periodic balloon dilation is beneficial for improving endometrial receptivity and has a significant clinical impact on patients with IUA undergoing IVF.

Effect of tamoxifen in patients with thin endometrium who underwent frozen-thawed embryo transfer cycles: a retrospective study

Introduction

Thin endometrium leads to an impaired implantation rate. The aim of the study is to compare the clinical outcomes of tamoxifen (TAM) and hormone replacement therapy (HRT) used in patients with thin endometrium (<7mm) in frozen-thawed embryo transfer (FET)cycles.

Methods

A total of 176 FET cycles with thin endometrium were retrospectively analyzed in our center from Jan 2020 to May 2022. According to patients' own will, 112 patients were allocated to the HRT group and 64 patients chose the TAM protocol. Clinical outcomes were compared between two groups.

Result

The duration of treatment was shorter in the TAM group(12.03±2.34d) than the HRT group (16.07±2.52 d), which was statistically different (p<0.05). The endometrial thickness on the transfer day of the TAM group (7.32±1.28 mm) was significantly thicker than that of the HRT group (6.85±0.89mm, p<0.05). The clinical pregnancy rate of the TAM group (50.0%) was higher than that of the HRT group (36.6%), but there was no significant difference (p >0.05). The early miscarriage rate was significantly lower in the TAM group compared with the HRT group (5.9% Vs 26.8%, adjusted OR 0.10, p<0.05), while the live birth rate was higher in the TAM group (46.9% Vs 26.8%, adjusted OR 2.24, p<0.05) compared with the HRT group.

Conclusion

For patients with thin endometrium, TAM effectively improved the endometrial thickness and increased the live birth rate. TAM can be used as an alternative protocol for patients with thin endometrium.

Association of angiotensin II and receptors in peri-implantation endometrium with microvessel density and pregnancy outcomes of women with recurrent implantation failure after embryo transfer

Purpose

Investigate whether local angiotensin II (AngII) and its AngII type 1 and 2 receptors (AT1R, AT2R) in the endometrium are different and correlate with microvessel density in women with reproductive failure and pregnancy outcomes.

Methods

Endometrium during the window of implantation from 40 women with recurrent miscarriage (RM) and 40 with recurrent implantation failure (RIF) were compared with 27 fertile women. Peri-implantation endometrium from 54 women prior to euploid embryo transfer were collected and compared in women with successful pregnancy and unsuccessful pregnancy.

Results

Compared with fertile women, expression of AT2R was significantly lower, while AT1R/AT2R expression ratio was significantly higher in the stroma of the RIF group. Endometrium arteriole MVD was significantly lower and negatively correlated with the AT1R/AT2R expression ratio in the stroma of the RIF group. No significant differences and correlations were found in the RM group. Compared with the pregnancy group, expression of AT1R and AT2R were significantly lower in all compartments, but only AT1R/AT2R ratio was significantly higher in the stroma of the non-pregnancy group. Similarly, endometrium arteriole MVD was also significantly lower and negatively correlated with the AT1R/AT2R ratio in the stroma of the non-pregnancy group.

Conclusion

Local renin-angiotensin system is dysregulated in peri-implantation endometrium and associated with abnormal angiogenesis in RIF and poor implantation outcome after embryo transfer.

Network Pharmacology Analysis of the Mechanisms Underlying the Therapeutic Effects of Yangjing Zhongyu Tang on Thin Endometrium

Purpose

Yangjing Zhongyu Tang (YJZYT) is a classic Chinese prescription for infertility treatment and exerts therapeutic effects via activity on the thin endometrium (TE). However, the major components and underlying mechanisms of YJZYT actions remain to be established. The main objectives of this study were to clarify the effects of YJZYT on the TE and provide insights into the related mechanisms based on network pharmacology and molecular docking analyses.

Methods

Network pharmacology was employed to explore the main bioactive components and targets of YJZYT. TE-related genes were obtained from the Genecards database and screened for intersections with YJZYT. The Cytoscape 3.8.2 was used to build a "compounds-disease-targets" network and molecular docking analysis performed on key targets. The mechanism of action of YJZYT was further validated in vivo using a rat model.

Results

A total of 98 YJZYT active ingredients, 2409 thin endometrium-associated genes, and 186 common targets were obtained. Through topological analysis, 10 core objectives were screened. Data from the PPI network suggest that AKT1, TNF, VEGFA, IL-6, TP53, INS, ESR1, MMP9, ALB, and ACTB serve as key targets in the action of YJZYT on TE. PI3K-Akt, TNF, apoptosis, IL-17 and MAPK were established as the main functional pathways. Molecular docking analysis revealed high affinity of the active ingredients of YJZYT, specifically, ursolic acid, palbinone, stigmasterol, and beta-sitosterol, for TNF, VEGFA, IL-6, AKT, and MMP9. YJZYT improved endometrial recovery, promoted endometrial angiogenesis, and upregulated protein expression of VEGF, PI3K, AKT, and p-AKT in the TE rat model.

Conclusion

Network pharmacological and animal studies facilitated the prediction and validation of the active components and key targets of YJZYT potentially contributing to TE. Preliminary evidence from in vivo experiments showed that YJZYT promotes angiogenesis and thin endometrial repair via regulation of the PI3K/AKT pathway, providing a reference for further research.

Treatment options for endometrial hypoproliferation

PURPOSE OF REVIEW

Endometrial hypoproliferation refers to the failure of the endometrium to reach optimal thickness during fresh or frozen embryo transfer cycles in women undergoing infertility treatment with in-vitro fertilization (IVF). This review discusses the treatment options for endometrial hypoproliferation.

RECENT FINDINGS

Apart from factors related to the embryo quality, ultrasonographic findings associated with the endometrium, such as endometrial thickness, endometrial pattern and subendometrial blood flow, are considered key factors associated with the outcome of assisted reproductive treatment. To date, a consensus has not been reached regarding the definition of thin endometrium, while thresholds of 6, 7 or 8 mm have been used in the literature. Strategies to increase endometrial thickness can be reviewed in three groups: endocrine approaches, vitamins & supplements, and new experimental therapeutic interventions. Some of the recently introduced experimental therapeutic interventions such as platelet-rich plasma injection, stem cell treatment and tissue bioengineering are exciting potential therapies that need to be further studied.

SUMMARY

Despite a large number of publications on the topic, diagnosing and treating endometrial hypoproliferation remains a challenge. Well designed studies are needed to establish a widely accepted endometrial thickness cut-off value below which endometrial hypoproliferation is diagnosed and to generate meaningful data that would allow an evidence-based discussion of available therapeutic options with patients.

The value of platelet-rich plasma in women with previous implantation failure: a systematic review and meta-analysis

OBJECTIVE

To assess the value of intrauterine PRP to improve IVF outcome in women with previous implantation failure.

METHODS

Screening of Pubmed, Web of Science, and other databases from inception to August 2022 using the keywords related to "platelet-rich plasma" OR "PRP" AND "IVF" "implantation failure." Twenty-nine studies (3308 participants) were included in our analysis, 13 were RCTs, 6 were prospective cohorts, 4 were prospective single arm, and 6 were retrospective analyses. Extracted data included settings of the study, study type, sample size, participants' characteristics, route, volume, timing of PRP administration, and outcome parameters.

RESULTS

Implantation rate was reported in 6 RCTs (886 participants) and 4 non-RCTs (732 participants). The odds ratio (OR) effect estimate was 2.62 and 2.06, with 95% CI of 1.83, 3.76, and 1.03-4.11, respectively. Endometrial thickness was compared in 4 RCTs (307 participants) and 9 non-RCTs (675 participants), which showed a mean difference of 0.93 and 1.16, with 0.59-1.27 and 0.68-1.65 95% CI, respectively.

CONCLUSION

PRP administration improves implantation, clinical pregnancy, chemical pregnancy, ongoing pregnancy, live birth rates, and endometrial thickness in women with previous implantation failure.

Efficacy of granulocyte colony-stimulating factor for infertility undergoing IVF: a systematic review and meta-analysis

OBJECTIVE

This study aimed to evaluate the effectiveness of granulocyte colony-stimulating factor (G-CSF) for infertility and recurrent spontaneous abortion.

METHODS

Existing research was searched in PubMed, Embase and Cochrane Library till Dec 2021. Randomized control trials (RCTs) that compared G-CSF administration with the control group in infertility women undergoing IVF were included. The primary outcomes included clinical pregnancy rate; the secondary outcomes included live birth rate, abortion ratebiochemical pregnancy rate, embryo implantation rate, as well as endometrial thickness.

RESULT(S)

20 RCTs were included in this study. G-CSF increased the clinical pregnancy rate (RR = 1.85; 95% CI: 1.07, 3.18) and the endometrial thickness (MD = 2.25; 95% CI: 1.58,2.92;) in patients with thin endometrium undergoing IVF. G-CSF increased the biochemical pregnancy rate (RR = 2.12; 95% CI: 1.54, 2.93), the embryo implantation rate (RR = 2.51; 95% CI: 1.82, 3.47) and the clinical pregnancy rate (RR = 1.93; 95% CI: 1.63, 2.29) in patients with a history of repeated implantation failure undergoing IVF. No differences were found in pregnancy outcomes of general IVF patients.

CONCLUSIONS

Granulocyte colony-stimulating factor is likely to be a potential option for infertility women undergoing IVF with thin endometrium or recurrent implantation failure .

TRIAL REGISTRATION

Retrospectively registered (The PROSPERO registration number: CRD42022360161).

Human Umbilical Cord Mesenchymal Stem Cell-Derived Exosome Repairs Endometrial Epithelial Cells Injury Induced by Hypoxia via Regulating miR-663a/CDKN2A Axis

Aim

Thin endometrium remains a severe clinical challenge with no effective therapy to date. We aimed at exploring the role and molecular mechanism of human umbilical cord mesenchymal stem cell- (hucMSC-) derived exosomes (hucMSC-Ex) in repairing hypoxic injury of endometrial epithelial cells (EECs).

Methods

Exosomes were harvested from the conditioned medium of hucMSC and characterized using western blot, transmission electron microscopy (TEM), flow cytometry, and nanoparticle tracking analysis (NTA). EECs were subjected to hypoxic conditions before cocultured with hucMSC-Ex. Cell viability, apoptosis, and migration were determined with CCK-8, flow cytometry, and wound healing assay, respectively. Apoptosis/EMT-related proteins were detected by western blot. The miRNA profiling was determined by RNA sequencing. The expression of miR-663a and CDKN2A was measured by qRT-PCR. MiR-663a in EECs was overexpressed by transfecting with miR-663a mimics.

Results

Mesenchymal stem cells (MSCs) markers CD73, CD90, and CD106 were positively expressed in hucMSCs. Exosome isolated from hucMSC expressed CD63 and TSG101, and were 100-150 nm in diameter. HucMSC-Ex promoted cell proliferation inhibited by hypoxia. And hucMSC-Ex also inhibited hypoxia-induced apoptosis, migration, and EMT of EECs by upregulating the expression of Bcl-2 and E-cadherin and downregulating Bax and N-cadherin levels. Further, bioinformatics research found that hucMSC-Ex coculture can significantly upregulate the expression of miR-663a and decrease the expression of CDKN2A in hypoxia-induced EECs. Furthermore, miR-663a overexpression inhibited CDKN2A expression and increased the expression of Bcl-2 and E-cadherin in hypoxia-induced EECs.

Conclusions

HucMSC-Ex promoted cell proliferation, inhibited cell apoptosis, migration, and EMT in hypoxia-induced EECs, thereby alleviating hypoxia-induced EECs injury, which may be related to its regulation of miR-663a/CDKN2A expression. Our study indicated that hucMSC-Ex might benefit for repairing thin endometrium.

P16 and P21 are involved in the pathogenesis of endometrial thinning: A cross-sectional study

P16 plays a role in the negative regulation of cell proliferation, regulating cell apoptosis to control the growth of tumor cells. P21 is a nuclear protein that suppresses DNA synthesis and inhibits cell division. This study aimed to examine the expression and roles of P16 and P21 in endometrial thinning. Thirty cases of endometrial biopsy diagnosed as endometrial thinning were assessed by p16 and p21 immunohistochemistry from March 2014 to August 2020 in Huazhong University of Science and Technology Union Shenzhen Hospital. Another thirty cases of normal endometrium in the same period were assessed as controls. The specimens underwent histological analysis, and P16 and P21 were assessed by immunohistochemistry. There were no statistically significant differences in age, menstrual cycle, BMI, sex hormone levels, gravidity and parity between the two groups (all P > .05). In the endometrial thinning group, P16 was expressed in the endometrial adenoid nucleus, cytolymph and interstitial cell nucleus. In the normal group, P16 was mainly expressed in the endometrial adenoid nucleus, with some P16 signals detected in the endometrial interstitial nucleus. P21 expression was mainly detected in the endometrial adenoid nucleus. P16 and P21 amounts in endometrial thinning cases were significantly lower than those of the normal endometrial group. There was no correlation between p16 and p21 amounts. This study revealed aberrant expression of P16 and P21 in the endometrium might be due to a compensatory effect of the thin endometrium to increase cell proliferation and suppress cell apoptosis. However, the pathological roles of P16 and P21 in endometrial thinning and the contribution of cell senescence deserve further investigation.

Network Pharmacology and Molecular Docking Approach to Reveal the Immunotherapeutic Mechanism of Cuscutae Semen in Treating Thin Endometrium

Objective. Thin endometrium is considered as a leading cause of infertility, recurrent pregnancy loss, and repeated implantation failure. The seed of Cuscutae Semen (CS) has been used to prevent aging and improve sexual function in Traditional Chinese Medicine. However, the pharmacological mechanism of CS in preventing and treating thin endometrium remains to be elucidated. Methods. Three public databases, TCMSP, GeneCards, and OMIM, were searched to collect the main active compounds and putative molecules of CS, as well as the targets of thin endometrium, respectively. The CS and thin endometrium common targets were subject to protein-protein interaction (PPI) analysis followed by functional enrichment analysis. The best binding mode of CS compounds and common target proteins was evaluated by molecular docking and analysis in the AutoDockTools. Results. In total, 11 main active compounds, 102 drug target proteins, and 70 CS and thin endometrium common targets were identified. There were 68 nodes with 722 edges in the PPI network; HIF1A, MYC, ESR1, and EGFR were the top 4 targets. After functional enrichment analysis, it was revealed that the therapeutic effects of active compounds of CS on thin endometrium were achieved through cellular response to chemical stress, transcription regulator, DNA-binding transcription factor binding, chemical carcinogenesis-receptor activation, lipid, and atherosclerosis. The molecular docking analysis revealed that the 3 active compounds of CS, quercetin, matrine, and isorhamnetin, have good binding ability with their targets, HIF1A, MYC, ESR1, and EGFR. Conclusion. Our study uncovers the main active compounds in CS and their corresponding targets related to thin endometrium which explains the pharmacological mechanism underlying therapeutic effects of CS on thin endometrium.

Granulocyte colony-stimulating factor in reproductive-related disease: Function, regulation and therapeutic effect

Granulocyte colony-stimulating factor (G-CSF) is one of the cytokines which plays important roles in embryo implantation and normal pregnancy. At the maternal-fetal interface, G-CSF can be synthesized by multiple cells, and participates in regulation of trophoblast development, endometrial decidualization, placental metabolism and angiogenesis. Moreover, as an important medium of intercellular communication, G-CSF has also been shown to exert key roles in crosstalk between cellular components at the maternal-fetal interface. Recently, our study demonstrated that G-CSF derived from M2 macrophage could promote trophoblasts invasion and migration through activating PI3K/AKT/Erk1/2 pathway, thereby involving in normal pregnancy program. Herein, we will summarize the role and regulation of G-CSF in normal pregnancy and reproductive-related disease, and the clinical applications of G-CSF in patients undergoing in vitro fertilization with thin endometrium, repeated implantation failure, and women suffered with recurrent spontaneous abortion.

The Role of Endometrial Stem/Progenitor Cells in Recurrent Reproductive Failure

Recurrent implantation failure (RIF) and recurrent pregnancy loss (RPL), collectively referred to as recurrent reproductive failure (RRF), are both challenging conditions with many unanswered questions relating to causes and management options. Both conditions are proposed to be related to an aberrant endometrial microenvironment, with different proposed aetiologies related to a restrictive or permissive endometrium for an invading embryo. The impressive regenerative capacity of the human endometrium has been well-established and has led to the isolation and characterisation of several subtypes of endometrial stem/progenitor cells (eSPCs). eSPCs are known to be involved in the pathogenesis of endometrium-related disorders (such as endometriosis) and have been proposed to be implicated in the pathogenesis of RRF. This review appraises the current knowledge of eSPCs, and their involvement in RRF, highlighting the considerable unknown aspects in this field, and providing avenues for future research to facilitate much-needed advances in the diagnosis and management of millions of women suffering with RRF.

The role of extracellular matrix on unfavorable maternal–fetal interface: focusing on the function of collagen in human fertility

Extracellular matrix (ECM) is characterized as widespread, abundant, and pluripotent. Among ECM members, collagen is widely accepted as one of the most prominent components for its essential structural property that can provide a scaffold for other components of ECM and the rich biological functions, which has been extensively used in tissue engineering. Emerging evidence has shown that the balance of ECM degradation and remodeling is vital to regulations of maternal–fetal interface including menstrual cycling, decidualization, embryo implantation and pregnancy maintenance. Moreover, disorders in these events may eventually lead to failure of pregnancy. Although the improvement of assisted conception and embryo culture technologies bring hope to many infertile couples, some unfavorable outcomes, such as recurrent implantation failure (RIF), recurrent pregnancy loss (RPL) or recurrent miscarriage (RM), keep troubling the clinicians and patients. Recently, in vitro three-dimensional (3D) model mimicking the microenvironment of the maternal–fetal interface is developed to investigate the physiological and pathological conditions of conception and pregnancy. The progress of this technology is based on clarifying the role of ECM in the endometrium and the interaction between endometrium and conceptus. Focusing on collagen, the present review summarized the degradation and regulation of ECM and its role in normal menstruation, endometrium receptivity and unsatisfying events occurring in infertility treatments, as well as the application in therapeutic approaches to improve pregnancy outcomes. More investigations about ECM focusing on the maternal–fetal interface interaction with mesenchymal stem cells or local immunoregulation may inspire new thoughts and advancements in the clinical application of infertility treatments.

Graphical abstract

Exosomes Derived From CTF1-Modified Bone Marrow Stem Cells Promote Endometrial Regeneration and Restore Fertility

Background: Thin endometrial tissue is a leading cause of embryo transfer failure, potentially contributing to sustained infertility and associated adverse outcomes. The application of exosomes derived from autologous or allogeneic bone marrow-derived stem cells (BMSCs) has been used to promote uterine repair following injury, and there is also prior evidence that stem cell transplantation can bolster fertility. Genetic modifications represent a primary approach to enhancing exosomal therapy strategies. The present study thus explored the effects of Cardiotrophin-1 (CTF1)-modified BMSCs-exo on fertility-related outcomes.

Methods: An adenoviral vector was used to generate CTF1-overexpressing BMSCs (C-BMSCs), after which exosomes were isolated from control BMSCs (BMSC-exos) and C-BMSCs (C-BMSC-exos). The angiogenic effects of C-BMSC-exo treatment were assessed through analyses of endothelial cell proliferation and tube formation. Model rats exhibiting endometrial thinning were administered C-BMSCs-exo, after which the effects of such treatment were assessed through H&E staining, Masson’s trichrome staining, and immunofluorescence analyses. The mechanistic basis for the proangiogenic effects of CTF1 as a driver of endometrial regeneration was additionally explored.

Results: C-BMSC-exo treatment of HUVECs was associated with enhanced neovascularization, as evidenced by improved in vitro proliferation, migration, and tube formation. Importantly, such treatment was also linked to tissue regeneration, neovascularization, and the suppression of localized tissue fibrosis in vivo. Regenerated endometrial tissue exhibited higher embryo receptivity and was associated with higher birth rates in treated rats. The upregulation of the JAK/PI3K/mTOR/STAT3 signaling pathways in C-BMSC-exo-treated rats may underscore the mechanistic basis whereby CTF1 can positively impact endometrial angiogenesis and regeneration.

Conclusion: Our data suggest that exosomes produced by CTF1-modified BMSCs can more effectively promote the regeneration of endometrial and myometrial tissues, driving neovascularization in a manner that improves endometrial receptivity in a rat model system, highlighting the therapeutic promise of this approach for patients diagnosed with endometrial thinning.

Diffusion kurtosis imaging for assessing endometrial fibrosis: a preliminary clinical study

PURPOSE

To investigate the feasibility of using diffusion kurtosis imaging (DKI) for the assessment of endometrial fibrosis.

METHODS

40 patients with hysteroscopy confirmed endometrial fibrosis and 30 healthy women underwent MR examination including the DKI sequence (b = 0, 500, 1000, 1500, and 2000 s/mm²). Endometrial thickness (ET), apparent diffusion coefficient (ADC), corrected ADC (D), and kurtosis of diffusion (K) were measured and compared, and the diagnostic performance of those parameters was evaluated using ROC curves analysis.

RESULTS

Patients with endometrial fibrosis had a thinner endometrium than the healthy controls (P < 0.001). They also had significantly lower ADC and D values and significantly higher K values of the endometrium than the healthy controls (all P < 0.001). ADC, D, K, and ET all performed excellently in diagnosing endometrial fibrosis, with areas under the curve (AUCs) of 0.940, 0.879, 0.860, and 0.853, respectively. ADC showed the highest AUC, demonstrating better diagnostic accuracy than K (z = 2.307, P < 0.05). However, there were no differences in AUC between D, K, and ET, or ADC, D, and ET (all P > 0.05). The reproducibility of ADC, D, and K values in patients with endometrial fibrosis and healthy controls was excellent (ICC 0.951-0.991).

CONCLUSION

DKI of the endometrium has promising potential for the noninvasive assessment of endometrial fibrosis.

Pregnancy Patterns Impact Live Birth Rate for Patients With Intrauterine Adhesions After Hysteroscopic Adhesiolysis: A Retrospective Cohort Study

Objective

The pregnancy patterns and other factors of live birth for patients with intrauterine adhesions (IUAs) were identified by analyzing the clinical features of pre-, intra-, and post-hysteroscopic adhesiolysis (HA).

Design

A total of 742 patients with IUAs who wanted to become pregnant underwent HA from January 2017 to May 2018 at the Third Xiangya Hospital of Central South University. The patient follow-up period was 2 years post-HA. A logistic regression was performed to analyze the clinical characteristics associated with a live birth for patients with IUAs. Pre-operative clinical indicators included age, gravidity, parity, abortion, IUA recurrence, menstrual patterns, disease course. Intraoperative clinical features assessed in the last operation were uterine cavity length, IUA appearance, IUA area, number of visible uterine cornua, number of visible tubal ostia, AFS scores. Pregnancy patterns were post-hysteroscopic adhesiolysis features.

Results

Among the 742 IUA patients, 348 (46.9%) had a live birth and 394 (53.1%) did not. A bivariate and binary logistic regression analysis showed that IUA patients’ pregnancy patterns, age, number of visible tubal ostia noted by a second-look hysteroscopy, and American Fertility Society (AFS) scores were significantly related to the live birth rate (P < 0.05).

Conclusions

Pregnancy patterns, age, number of visible tubal ostia, and AFS scores were significantly related to the live birth rate and may be considered potential predictors of the live birth rate in IUA patients. The indications of assisted reproductive technology (ART) might be a better choice for patients with recurrent IUAs.

Synergistic regenerative therapy of thin endometrium by human placenta-derived mesenchymal stem cells encapsulated within hyaluronic acid hydrogels

Background

Thin endometrium is a primary cause of defective endometrial receptivity, resulting in infertility or recurrent miscarriage. Much effort has been devoted toward regenerating thin endometrium by stem cell-based therapies. The human placenta-derived mesenchymal stem cells (HP-MSCs) are emerging alternative sources of MSCs with various advantages. To maximize their retention inside the uterus, we loaded HP-MSCs with cross-linked hyaluronic acid hydrogel (HA hydrogel) to investigate their therapeutic efficacy and possible underlying mechanisms.

Methods

Ethanol was injected into the mice uterus to establish the endometrium-injured model. The retention time of HP-MSCs and HA hydrogel was detected by in vivo imaging, while the distribution of HP-MSCs was detected by immunofluorescence staining. Functional restoration of the uterus was assessed by testing embryo implantation rates. The endometrial morphological alteration was observed by H&E staining, Masson staining, and immunohistochemistry. In vitro studies were further conducted using EdU, transwell, tube formation, and western blot assays.

Results

Instilled HP-MSCs with HA hydrogel (HP-MSCs-HA) exhibited a prolonged retention time in mouse uteri than normal HP-MSCs. In vivo studies showed that the HP-MSCs-HA could significantly increase the gland number and endometrial thickness (P < 0.001, P < 0.05), decrease fibrous area (P < 0.0001), and promote the proliferation and angiogenesis of endometrial cells (as indicated by Ki67 and VEGF, P < 0.05, P < 0.05, respectively) in mice injured endometrium. HP-MSCs-HA could also significantly improve the embryo implantation rate (P < 0.01) compared with the ethanol group. Further mechanistic study showed the paracrine effects of HP-MSCs. They could not only promote the proliferation and migration of human endometrial stromal cells via the JNK/Erk1/2-Stat3-VEGF pathway but also facilitate the proliferation of glandular cells via Jak2-Stat5 and c-Fos-VEGF pathway. In turn, the increased VEGF in the endometrium promoted the angiogenesis of endothelial cells.

Conclusion

Our study suggested the potential therapeutic effects and the underlying mechanisms of HP-MSCs-HA on treating thin endometrium. HA hydrogel could be a preferable delivery method for HP-MSCs, and the strategy represents a promising therapeutic approach against endometrial injury in clinical settings.

Graphical abstract

Supplementary Information

The online version contains supplementary material available at 10.1186/s13287-022-02717-2.

Frozen Blastocyst Embryo Transfer: Comparison of Protocols and Factors Influencing Outcome

Background: Various factors, including treatment protocols, can influence the outcomes of frozen embryo transfers (FETs). The study objectives were to compare different endometrial preparation protocols of FET cycles and to evaluate the factors, including the endometrial thickness (ET), that affect outcomes. Methods: This observational cohort study involved 5037 women undergoing FETs at eight tertiary clinics in the UK between January 2016 and March 2019. The endometrial preparation protocols used were natural cycle (NC-FETs), artificial hormone support cycle with oestradiol valerate but without pituitary downregulation (AC-FETs) and artificial hormone support cycle with agonist downregulation (ACDR-FETs). Results: The mean (±SD) ages across NC-FET, AC-FET and ACDR-FET groups were 36.5 (±4.2), 35.9 (±5.0) and 36.4(±4.9) years, respectively. LBRs were comparable (40.7%, 175/430; 36.8%, 986/2658; and 36.7%, 716/1949, respectively) across the three groups. Clinical pregnancy, implantation, multiple pregnancies, miscarriage and ectopic pregnancy rates were also similar. In the regression analysis of variables including age, duration of infertility, number of embryos transferred, protocol type and endometrial thickness, age was the only significant predictor of LBRs, although its predictive ability was poor (AUC: 0.55). With the overall LBR of the study population being 37.1%, the post-test probability of a live birth at an ET of <5 mm was 0%, and at 5–5.9, 6–6.9, 7–7.9 and 8–8.9 mm, the probabilities were 16.7%, 33.8%, 36.7% and 37.7%, respectively. The LBR remained above 35% up to the 14–14.9 mm range and then declined gradually to 23% for the 17–25 mm range. Conclusions: The FET outcomes were similar for the three protocols used for endometrial preparation. The protocol type and endometrial thickness were not predictive of FET outcomes; age was the only predictive variable, despite its low predictive ability.

[The role of health resort factors in preconception preparation of patients with reproductive disorders]

Reproductive dysfunction is a multifactorial problem, for the correction of which the most difficult are cases of pathology comorbidity. Individual preconception preparation, taking into account risk factors, is recognized as an effective measure to increase the chances of conception and prevent reproductive losses.

OBJECTIVE

Optimization of treatment and rehabilitation measures at the preconception stage in patients with reproductive disorders.

MATERIAL AND METHODS

The effectiveness of the use of natural and preformed physical factors in the preconception preparation of 180 women who underwent medical and rehabilitation measures in the health resort of the Altai Territory - the resort town of Belokurikha (Group 1, 79 patients) and outpatient conditions in the city of Barnaul (Group 2, 101 patients). Comprehensive spa treatment included climatotherapy, a combination of various methods: balneotherapy, peloidtherapy, physiotherapy and a prolonged course of herbal medicine.

RESULTS

In patients of the 1st group, who underwent a course of rehabilitation treatment in a sanatorium-resort environment, compared with patients of the 2nd group, early reproductive losses were less common during pregnancy (7.1% and 20.7%, respectively; p=0.04) and more frequent term deliveries occurred (92.8% and 77.2%, respectively; p=0.02). The most significant predictors of the ineffectiveness of preconception preparation were the presence in patients of: chronic cystitis and autoimmune thyroiditis with hypothyroidism; oligomenorrhea at the time of pregnancy planning; aggravated by early reproductive losses and long-term wearing of intrauterine contraception history; burdened heredity for violation of carbohydrate metabolism.

CONCLUSION

Comprehensive preconception preparation in the sanatorium-resort conditions of Belokurikha helps to increase the fertility of patients with reproductive disorders, the trophostimulating effect in the genital organs and the restoration of endometrial reception, which makes it possible to recommend this method for use in clinical practice.

Human menstrual blood-derived mesenchymal stem cells regulation of the EGF/Ras p21 pathway as a potential therapeutic target for thin endometrium

Background

Human infertility is caused by many factors, among which thin endometrium is the main reason for poor embryo implantation. Currently, stem cell therapy could be a potential approach in treating human endometrial disorder like thin endometrium. In this study, we aimed to explore the influence of menstrual stem cells from non-thin endometrium (NTE-MenSCs) and thin endometrium (TE-MenSCs) on the phenotype of endometrial epithelial cells (EECs).

Methods

The MenSCs were isolated from women with and without thin endometria, characterized and co-cultured with the EECs. The expression of cytokeratin 7 (CK7) was verified by immunofluorescence while the detection stem cell markers was determined flow cytometry. Osteogenic and adipogenic differentiation were induced in appropriate media. The quantitative real-time PCR and western blotting were respectively used for detecting the mRNA and protein expression levels, respectively. The CCK-8 assay was used for cell viability analysis whereas ELISA was used for the detection of cytokine levels.

Results

The results showed that the co-culture of NTE-MenSCs or TE-MenSCs and EECs promoted the proliferation, migration, and angiogenesis of endothelial progenitor cells differently. Furthermore, the TE-MenSCs promoted the expression of inflammation, vascularized adipose, and extracellular matrix related proteins. The epidermal growth factor (EGF)/Ras p21 pathway was found to mediate the influence of MenSCs on EECs.

Conclusions

These findings are vital in that they may promote stem cell therapy of thin endometrium and enable embryo implantation in humans with thin endometrium.

Bioengineered endometrial hydrogels with growth factors promote tissue regeneration and restore fertility in murine models

Extracellular matrix (ECM) hydrogels obtained from decellularized tissues are promising biocompatible materials for tissue regeneration. These biomaterials may provide important options for endometrial pathologies such as Asherman's syndrome and endometrial atrophy, which lack effective therapies thus far. First, we performed a proteomic analysis of a decellularized endometrial porcine hydrogel (EndoECM) to describe the specific role of ECM proteins related to regenerative processes. Furthermore, we investigated the ability of a bioengineered system-EndoECM alone or supplemented with growth factors (GFs)-to repair the endometrium in a murine model of endometrial damage. For this model, the uterine horns of female C57BL/6 mice were first injected with 70% ethanol, then four days later, they were treated with: saline (negative control); biotin-labeled EndoECM; or biotin-labeled EndoECM plus platelet-derived GF, basic fibroblast GF, and insulin-like GF 1 (EndoECM+GF). Endometrial regeneration and fertility restoration were evaluated by assessing the number of glands, endometrial area, cell proliferation, neaoangiogenesis, reduction of collagen deposition, and fertility restoration. Interestingly, regenerative effects such as an increased number of endometrial glands, increased area, high cell proliferative index, development of new blood vessels, reduction of collagen deposition, and higher pregnancy rate occurred in mice treated with EndoECM+GF. Thus, a bioengineered system based on EndoECM hydrogel supplemented with GFs may be promising for the clinical treatment of endometrial conditions such as Asherman's syndrome and endometrial atrophy. STATEMENT OF SIGNIFICANCE: In the last years, the bioengineering field has developed new and promising approaches to regenerate tissues or replace damaged and diseased tissues. Bioengineered hydrogels offer an ideal option because these materials can be used not only as treatments but also as carriers of drugs and other therapeutics. The present work demonstrates for the first time how hydrogels derived from pig endometrium loaded with growth factors could treat uterine pathologies in a mouse model of endometrial damage. These findings provide scientific evidence about bioengineered hydrogels based on tissue-specific extracellular matrix offering new options to treat human infertility from endometrial causes such as Asherman's syndrome or endometrial atrophy.

A robust metabolomics approach for the evaluation of human embryos from in vitro fertilization

The identification of the most competent embryos for transfer to the uterus constitutes the main challenge of in vitro fertilization (IVF). We established a metabolomic-based approach by applying Fourier transform infrared (FTIR) spectroscopy on 130 samples of 3-day embryo culture supernatants from 26 embryos that implanted and 104 embryos that failed. On examining the internal structure of the data by unsupervised multivariate analysis, we found that the supernatant spectra of nonimplanted embryos constituted a highly heterogeneous group. Whereas ∼40% of these supernatants were spectroscopically indistinguishable from those of successfully implanted embryos, ∼60% exhibited diverse, heterogeneous metabolic fingerprints. This observation proved to be the direct result of pregnancy's multifactorial nature, involving both intrinsic embryonic traits and external characteristics. Our data analysis strategy thus involved one-class modelling techniques employing soft independent modelling of class analogy that identified deviant fingerprints as unsuitable for implantation. From these findings, we could develop a noninvasive Fourier-transform-infrared-spectroscopy-based approach that represents a shift in the fundamental paradigm for data modelling applied in assisted-fertilization technologies.

Sildenafil Supplementation for Women Undergoing Infertility Treatments: A Systematic Review and Meta-Analysis of Randomized Controlled Trials

The aim of this systematic review and meta-analysis is to summarize data on the effectiveness of Sildenafil supplementation for women undergoing assisted reproduction techniques. This meta-analysis of randomized controlled trials (RCTs) evaluates the effects of Sildenafil administration during infertility treatments compared with a control group in infertile women. Outcomes evaluated were endometrial thickness (ETh) and the clinical pregnancy rate (CPR). The chemical pregnancy rate (ChPR) was also evaluated. Pooled results were expressed as the risk ratio (RR) or mean differences (MD) with a 95% confidence interval (95% CI). Women undergoing ovulation induction who received Sildenafil showed higher ETh and a higher CPR in comparison to controls. In this group, both the ETh and ChPR resulted in significantly higher values only with delayed start administration. Women undergoing fresh or frozen embryo transfer who received Sildenafil showed no significant advantages regarding ETh and CPR in comparison to controls. In this group, we found a significantly higher ChPR in women receiving Sildenafil. A subgroup analysis revealed significant advantages regarding ETh with oral administration for women undergoing fresh or frozen embryo transfer. Sildenafil therapy appears to improve endometrial thickness and pregnancy rate in women undergoing timed intercourses but it resulted not effective in IUI and IVF treatments. Further RCTs with rigorous methodology are still mandatory.

Granulocyte Colony-Stimulating Factor Combined With Transcutaneous Electrical Acupoint Stimulation in Treatment of Unresponsive Thin Endometrium in Frozen Embryo Transfer Cycles

Objective: This trial was designed to assess the treatment effects of granulocyte colony-stimulating factor (G-CSF) and transcutaneous electrical acupoint stimulation (TEAS) on thin endometrium in frozen-thawed embryo transfer (FET) cycles.

Methods: Ninety-nine patients with previous cancellations of embryo transfer were included, 56 of whom were prospectively treated with intrauterine perfusion of G-CSF in subsequent FET cycles. The selected patients were randomized into the G-CSF perfusion only group and the G-CSF perfusion combined with TEAS group. The other 43 patients were retrospectively included as controls.

Results: Compared to previous cycles, endometrial thickness was statistically significantly increased in the two treatment groups (5.97 ± 0.60, 7.52 ± 0.56, 6.14 ± 0.52, and 7.66 ± 0.44; P = 0.00 and 0.00, respectively). The increases in endometrial thickness suggested that no statistically significant difference was found between the two treatment groups. The G-CSF with TEAS group suggested a higher embryo implantation rate than the G-CSF perfusion only and control groups (33.33 and 29.1% and 33.33 and 17.39%; P = 0.412 and 0.091, respectively). The G-CSF combined with TEAS group demonstrated nominally higher clinical and ongoing pregnancy rates than the G-CSF perfusion-only group and controls, though, the difference was not statistically significant.

Conclusion: G-CSF has a potential role in improving endometrium thickness in patients with thin unresponsive endometrium in FET treatment cycles. In addition, when combined with TEAS, G-CSF perfusion treatment also improves the embryo implantation rate; however, randomized controlled trials are highly demanded to provide high-grade evidence regarding clinical pregnancy rate after G-CSF perfusion treatment.

Noninvasive assessment of endometrial fibrosis in patients with intravoxel incoherent motion MR imaging

Recently, few noninvasive methods have been reported to evaluate endometrial fibrosis. Our study was to investigate the feasibility of intravoxel incoherent motion (IVIM) MR imaging in the detection of endometrial fibrosis in patients with intrauterine injury. 30 patients with hysteroscopy-confirmed endometrial fibrosis and 28 healthy women were enrolled to undergo MR examination including the IVIM sequence. Endometrial thickness (ET); apparent diffusion coefficient (ADC); and IVIM parameters, including pure diffusion coefficient (D), pseudodiffusion coefficient (D*) and vascular fraction (f) were evaluated. A multivariable model combing ADC, D, and f values using binary logistic regression analysis was built to diagnose endometrial fibrosis. Endometrial fibrosis patients demonstrated lower endometrial ADC, D, f values and ET (all p < 0.05). The multivariable model, ADC, D, f values and ET performed well in diagnosing endometrial fibrosis with AUC of 0.979, 0.965, 0.920, 0.901 and 0.833, respectively. The multivariable model revealed a better diagnostic accuracy than D, f and ET (all p < 0.05). Although ADC achieved a better diagnostic value than ET (z = 2.082, p < 0.05), no difference in AUC was shown among ADC, D, and f (all p > 0.05); between ET and D (p > 0.05); and between ET and f (p > 0.05). The reproducibility of ADC, D, f and D* values in patients with endometrial fibrosis and healthy women were good to excellent (ICC: 0.614-0.951). IVIM parameters exhibit promising potential to serve as imaging biomarkers in the noninvasive assessment of endometrial fibrosis.

Determining diagnostic criteria and cause of recurrent implantation failure

PURPOSE OF REVIEW

Recurrent implantation failure (RIF) refers to the absence of implantation after repeated transfer of good embryos into a normal uterus. This review discusses the diagnostic criteria and cause of RIF.

RECENT FINDINGS

Regardless of the advancements in IVF practice, RIF is still a challenge that has to be solved. Exact definition of RIF is lacking today. For the initial evaluation, a rigorous algorithmic evaluation should be compromised with an individualized principle. Factors that might affect the number and quality of the oocyte and sperm cells should be investigated in order to obtain a good-quality embryo. Embryo assessment should be performed under ideal laboratory circumstances. The uterine environment should be carefully evaluated and the embryo should be transferred into the uterus at the most receptive time. Some of the newly introduced diseases and empirical treatment strategies, such as chronic endometritis, vaginal microbiota, immunologic profile and immunomodulator treatments, can be discussed with the couple under the light of adequate evidence-based information.

SUMMARY

New diagnostic and treatment modalities are needed to be introduced, which would be safe, efficient and efficacious after well-designed randomized controlled trials.

Approaches to Improve Endometrial Receptivity in Case of Repeated Implantation Failures

Repeated implantation failures are a constant challenge in reproductive medicine with a significant impact both on health providers and on infertile couples. Several approaches have been proposed so far as effective; however, accumulative data have clarified that most of the treatment options do not have the evidence base for a generalized application to be suggested by the relevant societies. Implantation failures are attributed to either poor quality embryos or to defected endometrial receptivity. The current review aims to summarize in a systematic way all the new trends in managing RIF via interference with endometrial receptivity. The authors focus mainly, but not exclusively, on endometrial injury prior to embryo transfer and endometrial priming with autologous cells or biological agents. To this direction, a systematic search of the Pubmed database has been conducted taking into account the emerged evidence of the last two decades. All the suggested interventions are herein presented and analyzed in terms of reproductive outcomes. It is evident that properly powered and designed randomized trials are needed to support a new standard approach in RIF treatment that will safely be incorporated in national and international guidelines.

Stem Cells and the Endometrium: From the Discovery of Adult Stem Cells to Pre-Clinical Models

Adult stem cells (ASCs) were long suspected to exist in the endometrium. Indeed, several types of endometrial ASCs were identified in rodents and humans through diverse isolation and characterization techniques. Putative stromal and epithelial stem cell niches were identified in murine models using label-retention techniques. In humans, functional methods (clonogenicity, long-term culture, and multi-lineage differentiation assays) and stem cell markers (CD146, SUSD2/W5C5, LGR5, NTPDase2, SSEA-1, or N-cadherin) facilitated the identification of three main types of endogenous endometrial ASCs: stromal, epithelial progenitor, and endothelial stem cells. Further, exogenous populations of stem cells derived from bone marrow may act as key effectors of the endometrial ASC niche. These findings are promoting the development of stem cell therapies for endometrial pathologies, with an evolution towards paracrine approaches. At the same time, promising therapeutic alternatives based on bioengineering have been proposed.

Construction and Optimization of an Endometrial Injury Model in Mice by Transcervical Ethanol Perfusion

This study aimed to establish a stable animal model of intrauterine adhesion (IUA) using a minimally invasive method that recapitulates the clinicopathologic characteristics of IUA. Mice were randomly divided into groups based on the ethanol treatment time (the EtOH-10 s, EtOH-20 s, EtOH-40 s, EtOH-1 min, and sham operation groups), and after the cervix was relaxed with phloroglucinol, the uterine horn was perfused with 95% ethanol through the cervix to induce endometrial injury. Eight days after the procedure, routine biochemical assays were performed to assess liver and kidney function; HE and Masson staining were used to assess uterine morphology and fibrosis; and immunohistochemistry was performed to evaluate the expression of CD31 and F4/80 in the endometrium. Furthermore, the fertility of mice in the EtOH-40 s group and the sham operation group was compared. As expected, the ethanol treatment time was positively correlated with the degree of uterine damage and kidney dysfunction in mice. In particular, the endometria of mice in the EtOH-40 s group were significantly thinner than those of mice in the sham operation group and exhibited severe necrosis, glandular loss, incomplete epithelial and glandular epithelial cell structure, severe tissue fibrosis, an activated inflammatory response, and a significant decrease in the number of fetuses, consistent with the clinical characteristics of severe IUA. In conclusion, this study resulted in successful establishment, by a minimally invasive transcervical ethanol perfusion technique, of a mouse model of endometrial injury, which could support an in-depth study of IUA pathogenesis and further promote the development of IUA therapies.

Endometrial regeneration with endometrial epithelium: homologous orchestration with endometrial stroma as a feeder

BACKGROUND

Thin endometrium adversely affects reproductive success rates with fertility treatment. Autologous transplantation of exogenously prepared endometrium can be a promising therapeutic option for thin endometrium; however, endometrial epithelial cells have limited expansion potential, which needs to be overcome in order to make regenerative medicine a therapeutic strategy for refractory thin endometrium. Here, we aimed to perform long-term culture of endometrial epithelial cells in vitro.

METHODS

We prepared primary human endometrial epithelial cells and endometrial stromal cells and investigated whether endometrial stromal cells and human embryonic stem cell-derived feeder cells could support proliferation of endometrial epithelial cells. We also investigated whether three-dimensional culture can be achieved using thawed endometrial epithelial cells and endometrial stromal cells.

RESULTS

Co-cultivation with the feeder cells dramatically increased the proliferation rate of the endometrial epithelial cells. We serially passaged the endometrial epithelial cells on mouse embryonic fibroblasts up to passage 6 for 4 months. Among the human-derived feeder cells, endometrial stromal cells exhibited the best feeder activity for proliferation of the endometrial epithelial cells. We continued to propagate the endometrial epithelial cells on endometrial stromal cells up to passage 5 for 81 days. Furthermore, endometrial epithelium and stroma, after the freeze-thaw procedure and sequential culture, were able to establish an endometrial three-dimensional model.

CONCLUSIONS

We herein established a model of in vitro cultured endometrium as a potential therapeutic option for refractory thin endometrium. The three-dimensional culture model with endometrial epithelial and stromal cell orchestration via cytokines, membrane-bound molecules, extracellular matrices, and gap junction will provide a new framework for exploring the mechanisms underlying the phenomenon of implantation. Additionally, modified embryo culture, so-called "in vitro implantation", will be possible therapeutic approaches in fertility treatment.

Effectiveness of electroacupuncture for thin endometrium in infertile women: study protocol for a single-blind, randomized controlled trial

BACKGROUND

Thin endometrium negatively impacts the reproductive function. Current treatments for thin endometrium do not always improve endometrial receptivity. Preliminary evidence suggests that electroacupuncture could have potential therapy for thin endometrium in infertile women. Thus, this randomized controlled trial was designed to test whether electroacupuncture can improve endometrial receptivity in infertile women with thin endometrium.

METHODS

This study is a randomized, single-blinded, controlled, clinical trial. A total of 142 eligible patients will be recruited and randomly assigned to the electroacupuncture (EA) group or the sham electroacupuncture (SEA) group in a 1:1 ratio. Participants will receive 36 sessions over three menstrual cycles (12 weeks in total), with the same acupoint prescription. The primary outcome of this trial is endometrial thickness in the midluteal phase. The secondary outcomes include endometrial pattern, resistance index (RI) and pulsatility index (PI) of bilateral uterine artery and endometrium blood flow, serum estradiol (E2) and progesterone (P), and pregnancy rate. The pregnancy rate will be evaluated during a 6-month follow-up after completion of the trial. All other outcomes will be evaluated before treatment, during the treatment of 1st, 2nd, and 3rd menstrual cycle, and 6 months after treatment.

DISCUSSION

If the outcome confirms the effectiveness of electroacupuncture for thin endometrium in infertile women, this treatment will be proposed for application in clinical practice.

TRIAL REGISTRATION

Chinese Clinical Trials Registry ChiCTR2 000029983. Registered on 18 February 2020.

Application of Hydrogel-Based Delivery System in Endometrial Repair

A receptive endometrium with proper thickness is essential for successful embryo implantation. However, endometrial injury caused by intrauterine procedures often leads to pathophysiological changes in its environment, resulting in subsequent female infertility. Among diverse treatment methods of endometrial injury, hydrogels are a class of hydrophilic three-dimensional polymeric network with biocompatibility as well as the capability of absorbing water and encapsulation, which have potential applications as a promising intrauterine controlled-release delivery system. This review summarizes recent advances in the approaches of endometrial repair and further focuses on the application of a hydrogel-based delivery system in endometrial repair, including its preparation, therapeutic loading considerations, clinical applications, as well as working mechanisms.

Application of autologous endometrial mesenchymal stromal/stem cells increases thin endometrium receptivity: a case report

Background

Pregnancy in cycles with the use of assisted reproductive technologies is possible only with the availability of good-quality embryos and a healthy receptive endometrium. The problem of lack of sensitivity of the endometrium is related to the syndrome of thin endometrium, which is caused by a number of factors. However, there is no single protocol for the treatment of this syndrome, the return/improvement of normal functionality of endometrial tissue, and obtaining the desired pregnancy.

Case presentation

We report a case of a 38-year-old Ukrainian woman with a number of unsuccessful tries at pregnancy in cycles with the use of assisted reproductive technologies. We describe a clinical case of the use of mesenchymal stem cells of the human endometrium for a woman with thin endometrial syndrome to increase its receptivity for pregnancy. The basic steps of patient management, protocol of sampling material for obtaining a cell product based on endometrial stem cells, their basic morphofunctional characteristics, and post-treatment procedures to obtain the desired pregnancy are described.

Conclusion

Application of autologous endometrial mesenchymal stem cells increases endometrial receptivity and the chance for pregnancy with use of assisted reproductive technologies.

Comparison of GnRH-a Prolonged Protocol and Short GnRH-a Long Protocol in Patients with Thin Endometrium for Assisted Reproduction: A Retrospective Cohort Study

Purpose

Gonadotrophin releasing hormone agonist (GnRH-a) is widely used for pituitary down-regulation and recruiting more follicles in assisted reproduction. However, no information is available on its value for patients with thin endometrial thickness.

Patients and Methods

This was a retrospective cohort study of 302 patients with endometrium <8 mm undergoing fresh embryo transfer at a fertility center of a university hospital from January 2016 and December 2018. In 148 cycles of the GnRH-a prolonged protocol, one depot of 3.75 mg GnRH-a was injected on day 2 of the menstrual cycle, while in 154 cycles of the short GnRH-a long protocol, 0.1 mg of GnRH-a was injected daily from the mid-luteal phase. The live birth rate and clinical pregnancy rate were compared between the two groups. Other outcome measures included the implantation rate, miscarriage rate, and characteristics of stimulation procedures.

Results

Live birth rates and clinical pregnancy rates were significantly higher in the GnRH-a prolonged protocol group than in the other group (36.5% vs 20.8%, P=0.002; 43.9% vs 28.2%, P=0.006, respectively). The live birth rate was significantly increased in the prolonged protocol group (crude OR: 2.190, 95% CI: 1.311, 3.660; adjusted OR: 2.458, 95% CI: 1.430, 4.224) compared with that in the reference group. The implantation rate of the former group was also significantly higher than that of the latter group (35.4% vs 15.9%, P=0.000). There was no significant difference in miscarriage rates between the two protocols. In terms of stimulation procedures, the GnRH-a prolonged protocol group required significantly higher Gn time (10.9 vs 9.5 days, P=0.000) and Gn consumption (2625.0 vs 2047.5 IU, P=0.000) than the short GnRH-a long protocol group.

Conclusion

The GnRH-a prolonged protocol in fresh embryo transfer cycles yielded better clinical outcomes of patients with thin endometrium than the short GnRH-a long protocol.

Improving reproductive outcomes of intrauterine insemination: Does endometrial scratch injury help? A randomised controlled trial

OBJECTIVE(S)

Current evidence suggests that endometrial injury improves clinical pregnancy rate while having no effect on miscarriages in women undergoing IVF/ICSI. However, there is no substantial evidence to advocate the use of endometrial injury to benefit the outcomes of IUI treatment. Additionally, there is no clear consensus about the ideal timing, underlying mechanism and optimum intensity of endometrial injury required. The study examines the effect of intentional endometrial injury/scratch in the early proliferative phase of stimulated cycle on reproductive outcomes (clinical and ongoing pregnancy rates and miscarriage occurrence) of intra-uterine insemination treatment (IUI).

STUDY DESIGN, SIZE, DURATION

This prospective, randomized control interventional study was conducted in a tertiary level teaching institution from April 2018 to February 2020. 150 eligible couples requiring IUI treatment who agreed to participate were randomly allocated on 1:1 basis to either control or intervention group. The trial participants received up to 3 cycles ovulation induction with clomiphene citrate and intra-uterine insemination. In addition, women in intervention group were subjected to endometrial scratch injury on day 6-7 of their stimulated cycle. 154 cycles in control arm and 128 cycles in intervention group were analyzed for clinical pregnancy, miscarriages and pain experienced by the women during endometrial scratch injury using the statistical package SPSS (version 21).

RESULT

Similar cumulative clinical pregnancy rates (12.5% Vs 13.6%, RR 1.21, 95% CI 0.44-3.37, p = 0.713), biochemical pregnancy rates (17.1% vs 22.9%, RR 1.43, CI 0.59-3.47, p = 0.421) and ongoing pregnancy rates (10.93% Vs 11.47%, RR 1.05, CI 0.35-3.21, p = 924) were observed in control and intervention arms. Likewise, the relative risk of miscarriage occurrence in the intervention arm was 1.32 (95% CI 0.39-4.32, p = 1.000) which was not statistically different from control group. Mean pain score of 6.93 on numerical pain rating scale was experienced by women whilst having endometrial scratch injury.

CONCLUSIONS

There is insufficient evidence to defend the use of endometrial scratch injury in intra-uterine insemination treatment, as it is moderately painful and have uncertain beneficial influence on reproductive outcomes.

Inflammatory Demyelinating Pseudotumor With Liver Dysfunction: IgG4 Related Disease With Primary Biliary Cholangitis

Immunoglobulin G4 related disease (IgG4-RD) is a recently recognized immune-mediated disease which is far from understanding. A case of inflammatory demyelinating pseudotumor had been confirmed as IgG4-RD according to pathology features and clinical context. Combined with liver dysfunction, IgG4 related sclerotic cholangitis was suspected. However, primary biliary cholangitis was finally diagnosed by immune marks and histopathological findings. This is the first report in which mass lesions in the brain parenchyma were caused by IgG4-RD while liver dysfunction was due to primary biliary cholangitis. The clinical features of IgG4-RD are miscellaneous, and the accumulation of case reports might enrich clinicians experience and broaden their horizons about this condition.

Perivascular Stem Cell-Derived Cyclophilin A Improves Uterine Environment with Asherman's Syndrome via HIF1α-Dependent Angiogenesis

Asherman's syndrome (AS) is characterized by intrauterine adhesions or fibrosis resulting from scarring inside the endometrium. AS is associated with infertility, recurrent miscarriage, and placental abnormalities. Although mesenchymal stem cells show therapeutic promise for the treatment of AS, the molecular mechanisms underlying its pathophysiology remain unclear. We ascertained that mice with AS, like human patients with AS, suffer from extensive fibrosis, oligo/amenorrhea, and infertility. Human perivascular stem cells (hPVSCs) from umbilical cords repaired uterine damage in mice with AS, regardless of their delivery routes. In mice with AS, embryo implantation is aberrantly deferred, which leads to intrauterine growth restriction followed by no delivery at term. hPVSC administration significantly improved implantation defects and subsequent poor pregnancy outcomes via hypoxia inducible factor 1α (HIF1α)-dependent angiogenesis in a dose-dependent manner. Pharmacologic inhibition of HIF1α activity hindered hPVSC actions on pregnancy outcomes, whereas stabilization of HIF1α activity facilitated such actions. Furthermore, therapeutic effects of hPVSCs were not observed in uterine-specific HIF1α-knockout mice with AS. Secretome analyses of hPVSCs identified cyclophilin-A as the major paracrine factor for hPVSC therapy via HIF1α-dependent angiogenesis. Collectively, we demonstrate that hPVSCs-derived cyclophilin-A facilitates HIF1α-dependent angiogenesis to ameliorate compromised uterine environments in mice with AS, representing the major pathophysiologic features of humans with AS.