Endometrial growth and uterine blood flow: a pilot study for improving endometrial thickness in the patients with a thin endometrium

Treating refractory thin endometrium through a novel way of activation and administration of Platelet-rich plasma in sexually active women: An interventional prospective cohort clinical study

A prospective cohort study investigated the effectiveness of platelet-rich plasma (PRP) infusion for refractory thin endometrium in 38 infertile patients. Patients showed significant improvement in endometrial thickness post-PRP injection, leading to successful implantation and pregnancy. The study revealed a negative correlation between antimullerian hormone (AMH) levels and the need for PRP interventions, suggesting higher ovarian reserve may reduce the necessity for repeated treatments. This implies AMH levels could serve as a prognostic indicator for treatment outcomes, aiding clinicians in optimizing protocols and reducing patient burden. Further research is needed to confirm these findings in larger and more diverse populations, along with exploring long-term reproductive success rates post-PRP treatment.

Maternal supplementation of curcumin-olive oil nanocomposite improves uteroplacental blood flow, placental growth and antioxidant capacity in goats

This experiment was designed to investigate the impact of curcumin-olive oil nanocomposite (CONC) supplementation on uteroplacental hemodynamics and ultrasonographic measurements as well as maternal oxidative status in midgestating goats. Twelve synchronized pregnant goats (85.58 ± 1.08 days of gestation; mean ± SD) were uniformly assigned to two groups (n = 6/group); the first group received daily oral supplementation of CONC (3 mg/kg body weight; nanocurcumin [NC] group) for 32 days, and the second group was offered physiological saline (control) following the NC group timeline. The goats of both groups were examined at 3-day intervals for middle uterine (MUA) and umbilical (UMA) arteries hemodynamics (pulsatility index [PI], resistive index [RI], systole/diastole [S/D] and blood flow rate [BFR]) and diameters, uteroplacental thickness (UPT), placentomes' diameter (PD) and echogenicity, steroid hormones (progesterone and estradiol 17β), oxidative biomarkers (total antioxidant capacity [TAC], catalase [CAT], malondialdehyde [MDA]), nitric oxide (NO) and blood cells DNA integrity. The UPT (p = 0.012) and PD (p = 0.021) values were higher in the NC group than in their counterparts' control group (D11-32). There were increases in diameter (p = 0.021 and p = 0.012) and decreases (p = 0.021, p = 0.016 and p = 0.041 [MUA]; p = 0.015, p = 0.023 and p = 0.011 [UMA] respectively) in Doppler indices (PI, RI and S/D) of the MUA and UMA in the NC group compared to the control group (D14-32). On D20-32 (MUA) and D14-32 (UMA), the NC goats had higher BFR than the control group (p = 0.021, 0.018 respectively). The means of blood cells with fragmented DNA were lower (p = 0.022) in the NC group than in the control group on Days 8 and 21 postsupplementation. There were increases in CAT and NO (D20-32; p = 0.022 and p = 0.004 respectively), and TAC (D17-32; p = 0.007) levels in the NC goats compared to the control ones. The NC group had lower (p = 0.029) concentrations of MDA than the control group on Day 20 postsupplementation onward. In conclusion, oral supplementation of CONC improved uteroplacental blood flow and the antioxidant capacity of midgestating goats.

Comparison of Letrozole and Clomiphene Citrate in Pregnancy Outcomes in Patients with Polycystic Ovary Syndrome: A Systematic Review and Meta-analysis

Clomiphene citrate (CC) and letrozole are the predominant medical interventions for the management of infertility in patients with polycystic ovary syndrome (PCOS). To comprehensively summarize the evidence, a systematic review and meta-analysis of randomized clinical trials (RCTs) was carried out to assess the effect of letrozole and CC on pregnancy outcomes in PCOS patients. We searched PubMed/MEDLINE, Scopus, and Cochrane Central Register of Controlled Trials from inception to January 2023. We included RCTs conducted on PCOS women comparing letrozole to CC and assessing endometrial thickness, the number and size of follicles, and ovulation and pregnancy rates. The endpoints were summarized as risk ratio (RR) or standardized mean difference (SMD) with 95% confidence interval (CI) using the random-effects model. Heterogeneity was examined using the I2 statistic. Fifty trials met our inclusion criteria. The mean endometrial thickness was significantly higher in the letrozole group compared to CC group (SMD: 0.89; 95% CI: 0.49, 1.28; I2=97.72%); however, the number of follicles was higher in the CC group (SMD: -0.56; 95% CI: -0.96, -0.17; I2=96.34%). Furthermore, letrozole intake induced higher ovulation rate (RR: 1.20; 95% CI: 1.13, 1.26; I2=54.49%) and pregnancy rate (RR: 1.44; 95% CI: 1.28, 1.62; I2=65.58%) compared to CC. Compared to CC, letrozole has a positive effect on endometrial thickness, monofollicular development, and ovulation and pregnancy rates suggesting that letrozole may be a strong alternative to CC as a first-line medical intervention for chronic anovulation in PCOS women. Larger studies are warranted to further clarify these findings.

Sodium alginate hydrogel integrated with type III collagen and mesenchymal stem cell to promote endometrium regeneration and fertility restoration

A thinner endometrium has been linked to implantation failure, and various therapeutic strategies have been attempted to improve endometrial regeneration, including the use of mesenchymal stem cells (MSCs). However, low survival and retention rates of transplanted stem cells are main obstacles to efficient stem cell therapy in thin endometrium. Collagen type III is a key component of the extracellular matrix, plays a crucial role in promoting cell proliferation and differentiation, and has been identified as the major collagen expressed at the implantation site. Herein, composite alginate hydrogel containing recombinant type III collagen (rCo III) and umbilical cord mesenchymal stem cells are developed. rCo III serves as favorable bioactive molecule, displaying that rCo III administration promotes MSCs proliferation, stemness maintenance and migration. Moreover, rCo III administration enhances cell viability and migration of mouse endometrial stromal cells (ESCs). In a mouse model of thin endometrium, the Alg-rCo III hydrogel loaded with MSCs (MSC/Alg-rCo III) significantly induces endometrial regeneration and fertility enhancement in vivo. Further studies demonstrate that the MSC/Alg-rCo III hydrogel promoted endometrial function recovery partly by regulating mesenchymal-epithelial transition of ESCs. Taken together, the combination of Alg-rCo III hydrogel and MSCs has shown promising results in promoting endometrium regeneration and fertility restoration, and may provide new therapeutic options for endometrial disease.

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

The endometrium is a unique human tissue with an extraordinary ability to undergo a hormone-regulated cycle encompassing shedding, bleeding, scarless repair, and regeneration throughout the female reproductive cycle. The cyclical repair and regeneration of the endometrium manifest as changes in endometrial epithelialization, glandular regeneration, and vascularization. The mechanisms encompass inflammation, coagulation, and fibrinolytic system balance. However, specific conditions such as endometriosis or TCRA treatment can disrupt the process of cyclical endometrial repair and regeneration. There is uncertainty about traditional clinical treatments' efficacy and side effects, and finding new therapeutic interventions is essential. Researchers have made substantial progress in the perspective of regenerative medicine toward maintaining cyclical endometrial repair and regeneration in recent years. Such progress encompasses the integration of biomaterials, tissue-engineered scaffolds, stem cell therapies, and 3D printing. This review analyzes the mechanisms, diseases, and interventions associated with cyclical endometrial repair and regeneration. The review discusses the advantages and disadvantages of the regenerative interventions currently employed in clinical practice. Additionally, it highlights the significant advantages of regenerative medicine in this domain. Finally, we review stem cells and biologics among the available interventions in regenerative medicine, providing insights into future therapeutic strategies.

Hyperbaric oxygen therapy: a possible choice for patients with resistant thin endometrium during frozen embryo transfer treatments

BACKGROUND

Thin endometrium is considered suboptimal for embryo implantation, leading to compromised pregnancy rates without effective therapies. While some studies have reported promoted endometrial growth after a period of hyperbaric oxygen therapy (HBOT) in patients with intrauterine adhesion, there have been no reports in patients with resistant thin endometrium. The purpose of this study was to investigate the impact of HBOT on endometrium growth and pregnancy outcomes in patients with resistant thin endometrium during frozen embryo transfer (FET) treatments.

METHODS

This prospective pre-post cohort study was conducted at a university-affiliated assisted reproductive medical center between October 2021 and December 2022. Patients who had experienced at least one canceled transfer cycle due to a thin endometrium(< 7 mm) on the endometrium transformation day, despite the use of standard therapies as well as adjuvant therapies, were enrolled in the study. Patients were assigned voluntarily to either the HBOT group or the concurrent control group. The HBOT group received daily HBOT for at least 10 days during the proliferative phase, in addition to the routine endometrium preparation methods and the concurrent control group underwent cycles without HBOT. Propensity score matching (PSM) was used to ensure comparability between the groups. Both self-control and case-control comparisons were conducted. The primary outcome measured was endometrial thickness (ET) on the day of endometrium transformation. Secondary outcomes included intrauterine pregnancy rate (IPR), embryo implantation rate (IR), miscarriage rate, and others.

RESULTS

Patients in the HBOT group demonstrated a significantly thicker endometrial thickness on the day of endometrium transformation after undergoing therapy (5.76 ± 1.66 vs. 6.57 ± 1.23, P = 0.002). This improvement was accompanied by a decreased rate of cycle cancellations. Baseline parameters and endometrial thickness were comparable between the HBOT group and the concurrent control group during the cycle. The IPR was similar in patients who received cleavage-stage embryos (0.0% vs. 6.7%, P = 1.00), but significantly higher in patients in the HBOT group who received blastocysts (53.8% vs. 18.2%, P = 0.017).

CONCLUSIONS

A period of HBOT prior to endometrium transformation contributes to increased endometrial thickness and facilitates blastocyst implantation in patients with resistant thin endometrium during FET treatments.

TRIAL REGISTRATION

The trial was registered on the Chinese Clinical Trial Registry (registration no. ChiCTR2300072831, retrospectively registered).

Autologous Platelet-Rich Plasma (PRP) Efficacy on Endometrial Thickness and Infertility: A Single-Centre Experience from Romania

(1) Background: During IVF (in vitro fertilization), a proper endometrium thickness is one of the most difficult parameters to achieve and one of the most important prognostic factors of the success rate. One major problem is the high cancelation percentage in frozen embryo transfer cycles. The focus on the adjuvant methods for improving endometrium thickness is an on-going subject of interest. (2) Methods: This prospective single-arm self-control study was conducted in an IVF centre in Oradea, Romania. The patients were divided into two groups. The control group included 51 patients with at least one attempt to transfer a good-quality blastocyst, but the endometrial thickness did not surpass 7 mm under standard endometrial preparation protocol with oestradiol and with adjuvant therapy (other than PRP, such as aspirin, vitamin C, and vitamin E), and the study group included the same 51 patients that had the embryo transfer performed under the same standard endometrial preparation protocol with oestradiol preparation protocol and intrauterine PRP infusion. (3) Results: In our study, the PRP treatment had a positive impact on the parameters that were followed for the evaluation of the success rate of the embryo transfer procedure. The endometrial thickness (an increase in endometrial thickness by 0.6 mm after PRP treatment with p = 0.0001) and the clinical pregnancy rate (having a MD ± SD of 0 ± 0.38 before PRP treatment and with an increase to 0.5 ± 0.1 after the PRP treatment, p = 0.0004) were statistically significant (4) Conclusions: PRP has a positive effect in promoting endometrial proliferation, improving embryo implantation rate and clinical pregnancy rate for women with thin endometrium.

Effect of endometrial thickness on obstetric and neonatal outcomes in assisted reproduction: a systematic review and meta-analysis

PURPOSE

This systematic review and meta-analysis aimed to explore the relationship of endometrial thickness (EMT) with obstetric and neonatal outcomes in assisted reproductive cycles.

METHODS

PubMed, EMBASE, Cochrane Library and Web of Science were searched for eligible studies through April 2023. Obstetric outcomes include placenta previa, placental abruption, hypertensive disorders of pregnancy (HDP), gestational diabetes mellitus (GDM) and cesarean section (CS). Neonatal outcomes include birthweight, low birth weight (LBW), gestational age (GA), preterm birth (PTB), small for gestational age (SGA) and large for gestational age (LGA). The effect size was estimated as odds ratio (OR) or mean difference (MD) with 95% confidence interval (CI) using a random-effects model. Inter-study heterogeneity was assessed by the chi-square homogeneity test. One-study removal method was used to determine the sensitivity of the meta-analysis.

RESULTS

Nineteen studies involving 76,404 cycles were included. The pooled results revealed significant differences between the thin endometrium group and the normal group in placental abruption (OR = 2.45, 95% CI: 1.11-5.38, P = 0.03; I² = 0%), HDP (OR = 1.72, 95% CI: 1.44-2.05, P < 0.0001; I² = 0%), CS (OR = 1.33, 95% CI: 1.06-1.67, P = 0.01; I² = 77%), GA (MD = -1.27 day, 95% CI: -2.41- -1.02, P = 0.03; I² = 73%), PTB (OR = 1.56, 95% CI: 1.34-1.81, P < 0.0001; I² = 33%), birthweight (MD = -78.88 g, 95% CI: -115.79- -41.98, P < 0.0001; I² = 48%), LBW (OR = 1.84, 95% CI: 1.52-2.22, P < 0.00001; I² = 3%) and SGA (OR = 1.41, 95% CI: 1.17-1.70, P = 0.0003; I² = 15%). No statistical differences were found in placenta previa, GDM, and LGA.

CONCLUSION

Thin endometrium was associated with lower birthweight or GA and higher risks of placental abruption, HDP, CS, PTB, LBW and SGA. Therefore, these pregnancies need special attention and close follow-up by obstetricians. Due to the limited number of included studies, further studies are needed to confirm the results.

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.

Intrauterine botulinum toxin A administration promotes endometrial regeneration mediated by IGFBP3-dependent OPN proteolytic cleavage in thin endometrium

Adequate endometrial growth is a critical factor for successful embryo implantation and pregnancy maintenance. We previously reported the efficacy of intrauterine administration of botulinum toxin A (BoTA) in improving the endometrial angiogenesis and the rates of embryo implantation. Here, we further evaluated its potent therapeutic effects on the uterine structural and functional repair and elucidated underlying molecular regulatory mechanisms. This study demonstrated that a murine model of thin endometrium was successfully established by displaying dramatically decreased endometrial thickness and the rates of embryo implantation compared to normal endometrium. Interestingly, the expressions of insulin-like growth factor binding protein-3 (IGFBP3) and an active 35 kDa-form of osteopontin (OPN) were significantly reduced in thin endometrium, which were almost fully restored by intrauterine BoTA administration. Neutralization of BoTA-induced IGFBP3 subsequently suppressed proteolytic cleavage of OPN, exhibiting un-recovered endometrial thickness even in the presence of BoTA administration, suggesting that BoTA-induced endometrial regeneration might be mediated by IGFBP3-dependent OPN proteolytic cleavage. Our findings suggest that intrauterine BoTA administration improves the endometrial environment in our murine model with thin endometrium by increasing endometrial receptivity and angiogenesis in a manner dependent on the regulatory effect of IGFBP3 on OPN proteolytic cleavage, proposing BoTA as an efficient therapeutic strategy for the patients with thin endometrium.

Research progress of stem cell therapy for endometrial injury

Endometrial damage is an important factor leading to infertility and traditional conventional treatments have limited efficacy. As an emerging technology in recent years, stem cell therapy has provided new hope for the treatment of this disease. By comparing the advantages of stem cells from different sources, it is believed that menstrual blood endometrial stem cells have a good application prospect as a new source of stem cells. However, the clinical utility of stem cells is still limited by issues such as colonization rates, long-term efficacy, tumor formation, and storage and transportation. This paper summarizes the mechanism by which stem cells repair endometrial damage and clarifies the material basis of their effects from four aspects: replacement of damaged sites, paracrine effects, interaction with growth factors, and other new targets. According to the pathological characteristics and treatment requirements of intrauterine adhesion (IUA), the research work to solve the above problems from the aspects of functional bioscaffold preparation and multi-functional platform construction is also summarized. From the perspective of scaffold materials and component functions, this review will provide a reference for comprehensively optimizing the clinical application of stem cells.

Effect of Maternal Sildenafil Supplementation During Gestation on the Reproductive Performance of Sows/Gilts and Growth Performance of Neonatal Piglets

Sildenafil, a phosphodiesterase 5 (PDE-5) inhibitor, provides an alternative and effective strategy to increase uterine blood flow and vascular development, thus improving fetal development. Previous studies have shown that sildenafil attenuates fetal growth restriction in rodents, sheep, and humans. However, the effect of sildenafil intervention on fetal growth in pigs remains unclear. This study aims to evaluate the effect of dietary supplementation with sildenafil on the reproductive performance of sows and gilts. Over 700 Landrace × Large White crossbred sows in the 3rd or 4th parity were randomly assigned to the control group and the sildenafil treatment groups. In brief, sows in the treatment groups were given a basic diet supplemented with sildenafil (0.32 g/day) during different stages of gestation: (1) gestation day (GD) 0–110; (2) GD 0–30; (3) GD 30–80; (4) GD 80–110; and (5) GD 30–110. At parturition, the total number of piglets born per litter, the number of piglets born alive or dead, the average birth weight, the number of weaned piglets, and the average weaning weights were recorded and analyzed. Sildenafil supplementation throughout gestation (GD 0–110) increased both the litter size and the average birth weight. To reduce the cost of extended sildenafil supplementation, time-phased strategies were further tested. Sildenafil supplementation during early gestation (GD 0–30), mid-gestation (GD 30–80), and late gestation (GD 80–110) partially improved litter performance. Notably, sows fed sildenafil supplementation from the mid-to-late gestation period (GD 30–110) showed significantly improved litter performance, approaching the levels in the sows supplemented with sildenafil throughout the whole gestation period. Taken together, our results showed that maternal sildenafil supplementation during gestation can effectively improve the reproductive performance of sows and gilts, and enhance the growth performance of neonatal piglets, thus providing a promising and practical intervention strategy to improve reproductive management in pig farming.

Comparison of Efficacy Between Vaginal Sildenafil and Granulocyte-Colony Stimulating Factor (G-CSF) in Improving Endometrial Thickness (ET) in Infertile Women

Background

Infertility is presently an emanating preventive medicine issue with some severe societal repercussions associated with it. In India, approximately a score percent of couples bear the burden of infertility. Moreover, the declining fertility rates despite effective artificial reproductive techniques and increasing development of modern reproductive medicine from the last two censuses pose an alarm to the demographic progression data. Many studies have highlighted the importance of shifting the research focus to endometrial receptivity for increasing clinical pregnancy. 

Objective 

This research aims to compare the efficacy of treatments of vaginal sildenafil citrate and granulocyte-colony stimulating factor (G-CSF) intrauterine injection in increasing endometrial thickness (ET).

Methodology 

This was a randomized control trial (RCT) conducted over a two months period. Women seeking infertility treatment were recruited from the hospital's gynecological outpatient department (OPD). After the subjects gave informed consent, their history, clinical examination, and investigations were assessed. From the sixth day of the menstrual cycle, group A and group B had serial trans-vaginal ultra-sonographic evaluations for baseline endometrial thickness measurements. From day six to day 12 of the menstrual cycle, patients of group A were requested to self-administer per vaginal sildenafil citrate 25 mg every six hours. ET was evaluated sonographically on day 12 and day 14 of their menstrual cycle. Patients of group B received G-CSF 300 mcg/ml as intrauterine instillation on day 10 and were evaluated sonographically on day 12 and day 14 of their menstrual cycle. Patients then underwent additional therapy in the form of intrauterine injection (IUI), intracytoplasmic sperm injection with/without embryo transfer (ICSI/ET), or a natural cycle. Paired as well as unpaired t-tests were applied to the study groups to detect significant differences in the measurement of endometrial thickness before and after treatment.

Results

It was noticed that both sildenafil and G-CSF are agents for increasing endometrial thickness. The mean increase in endometrial thickness in the sildenafil treated group was 3.87 mm, while the mean increase in endometrial thickness in G-CSF treated group was 3.27 mm.

Conclusion 

This study has evidence of better results in improving endometrial thickness in infertile women by using vaginal sildenafil with respect to endometrial growth with an intrauterine infusion of granulocyte colony-stimulating factor (filgrastim, G-CSF).

Effectiveness of phosphodiesterase type 5 inhibitors on the treatment of thin endometrium and pregnancy outcomes: An systematic review

Phosphodiesterase type 5 (PDE5) inhibitors are thought to play a role in increasing endometrial thickness and increasing the success rate of pregnancy outcomes. This study was done to investigate the effects of PDE5 inhibitors on infertile women with thin endometrium and pregnancy outcomes. In this systematic review, all randomized controlled trials (RCTs) and observational studies were retrieved from databases including Institute for Scientific Information (ISI), PubMed, and Scopus by interesting keywords. A checklist was designed to collect necessary data and pregnancy outcomes, and the required items were recorded. PDE5 inhibitors through various mechanisms such as induction of vasodilatory effect through the effect on NO/cGMP signaling on vascular smooth muscle, through regulating cells proliferation and induction angiogenesis by increasing the expression of tumor suppressor factor (p53), and vascular endothelial growth factor A (VEGF-A) and downregulating inflammation by downregulating proinflammatory cytokines, affect endometrial thickness that eventually increases and pregnancy outcomes. Although PDE5s inhibitors increase endometrial thickness by different mechanisms, especially in women with thin endometrial, this does not necessarily mean that they induce a positive effect in all situations. However, their positive effects on pregnancy outcome may be affected by the time of administration, type of infertility treatment, underlying diseases such as pelvic disorders and inflammation. So in this regard, there are still ambiguous aspects that required further RCTs study in this area.

Prostaglandin and antigestagen in pyometra bitches: vascular and stereological effect

Effects of conservative treatment on uterine blood flow and morphometric findings are still unknown in bitches. Thus, this study aimed to compare uterine changes of pyometra bitches subjected to distinct modes of treatment. Pyometra bitches were assigned to: OHE (ovariohysterectomy immediately after diagnosis), Aglepristone (days 1, 2 and 8) and Associative (aglepristone treatment coupled with cloprostenol for 7 days) groups. After 9 days, bitches were ovariohysterectomized. Before surgery, uterine area was measured ultrasonographically and the uterine artery Doppler velocimetry analyzed blood flow velocity and indexes. Uterine horns were classified according to resistance index (RI) as more compromised and less compromised. Endometrial vasculature was quantitatively evaluated by color flow Doppler. Blood samples were collected to determine nitric oxide (NO) concentrations. Histological uterine structures were quantified by stereology and VEGF-A (vascular endothelial growth factor) and eNOS were (endothelial nitric oxide synthase) immunohistochemically analyzed. Aglepristone and Associative groups had lower uterine area and vascularization, and higher blood flow velocity and indexes compared to OHE group. Less compromised horn of Associative group had higher blood flow velocity compared to OHE group. Aglepristone group presented lower inflammatory infiltrate and larger uterine stroma. Associative group had lower volume density and absolute surface of endometrial cysts and lower VEGF-A expression for glandular epithelium and stromal cells. Blood NO and e-NOS immunostaining were not different among groups. In conclusion, association between aglepristone and prostaglandin is more effective in decreasing uterine vascularization and modulating uterine blood flow. Moreover, associative therapy promotes marked morphological changes.

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.

Sildenafil citrate-loaded targeted nanostructured lipid carrier enhances receptivity potential of endometrial cells via LIF and VEGF upregulation

The main objective of this research is to prepare sildenafil citrate (SC)-loaded arginyl-glycyl-aspartic acid (RGD)-containing nanostructured lipid carrier (SC-loaded NLC-RGD) and evaluate their effects on the receptivity potential of endometrial cells. Hot homogenization method was used to prepare SC-loaded NLC-RGD. Then, size, drug encapsulation, and morphology of prepared nanoparticles were studied by photon correlation spectroscopy technic, ultrafiltration method, and scanning electron microscopy, respectively. Subsequently, the influence of SC-loaded NLC-RGD on endometrial receptivity was evaluated by in vitro implantation assay. Finally, expression of vascular endothelial growth factor (VEGF), leukemia inhibitory factor (LIF), and integrin beta 3 (as endometrial receptivity markers) was assessed in SC-loaded NLC-RGD-treated endometrial cells by reverse transcription polymerase chain reaction (RT-PCR). Particles with a nano-size diameter (92.7 nm), appropriate polydispersity index (0.21), spherical morphology, and acceptable loading efficiency were prepared. In vitro implantation assay showed that SC, SC-loaded NLC, and SC-loaded NLC-RGD improve the rate of endometrial attachment potential by 1.6 ± 0.4, 1.7 ± 0.3, and 2.3 ± 0.3 times, respectively. Analysis of RT-PCR results showed the enhancing mRNA of LIF and VEGF in SC-treated endometrial cells. Results also confirmed the higher influence of SC-loaded NLC-RGD on gene expression patterns in comparison to SC. Using NLC-RGD as a carrier to deliver SC to endometrial cells is an effective approach to improve endometrial receptivity. Upregulation of LIF and VEGF is the probable mechanism by which SC enhances the endometrial receptivity potential.

Strategies for managing asherman's syndrome and endometrial atrophy: Since the classical experimental models to the new bioengineering approach

Endometrial function is essential for embryo implantation and pregnancy, but managing endometrial thickness that is too thin to support pregnancy or an endometrium of compromised functionality due to intrauterine adhesions is an ongoing challenge in reproductive medicine. Here, we review current and emerging therapeutic and experimental options for endometrial regeneration with a focus on animal models used to study solutions for Asherman's syndrome and endometrial atrophy, which both involve a damaged endometrium. A review of existing literature was performed that confirmed the lack of consensus on endometrial therapeutic options, though promising new alternatives have emerged in recent years (platelet-rich plasma, exosomes derived from stem cells, bioengineering-based techniques, endometrial organoids, among others). In the future, basic research using established experimental models of endometrial pathologies (combined with new high-tech solutions) and human clinical trials with large population sizes are needed to evaluate these emerging and new endometrial therapies.

Effects of sex and estrous cycle on the brain and plasma arginine metabolic profile in rats

L-arginine is a versatile amino acid with a number of bioactive metabolites. Increasing evidence implicates altered arginine metabolism in the aging and neurodegenerative processes. The present study, for the first time, determined the effects of sex and estrous cycle on the brain and blood (plasma) arginine metabolic profile in naïve rats. Female rats displayed significantly lower levels of L-arginine in the frontal cortex and three sub-regions of the hippocampus when compared to male rats. Moreover, female rats had significantly higher levels of L-arginine and γ-aminobutyric acid, but lower levels of L-ornithine, agmatine and putrescine, in plasma relative to male rats. The observed sex difference in brain L-arginine appeared to be independent of the enzymes involved in its metabolism, de novo synthesis and blood-to-brain transport (cationic acid transporter 1 protein expression at least), as well as circulating L-arginine. While the estrous cycle did not affect L-arginine and its metabolites in the brain, there were estrous cycle phase-dependent changes in plasma L-arginine. These findings demonstrate the sex difference in brain L-arginine in the estrous cycle-independent manner. Since peripheral blood has been increasingly used to identify biomarkers of brain pathology, the influences of sex and estrous cycle on blood arginine metabolic profile need attention when experimental research involves female rodents.

Effects of bone marrow mesenchymal stem cells on repair and receptivity of damaged endometrium in rats

AIM

This study was to investigate whether bone marrow mesenchymal stem cells (BMSCs) can repair damaged endometrium in rats and its effect on endometrial receptivity.

METHODS

A rat model of endometrial damage was established by heat injury. BMSCs were labeled with PKH26 and were transplanted into the right uterine cavity. The endometrial thickness and fertility testing were examined to assess the repair of damaged endometrium. The mass on trichrome staining was used to assess the endometrium fibrosis. The expression of integrin avβ3 and leukemia inhibitory factor (LIF) in rat endometrium was used to evaluate the endometrial receptivity.

RESULTS

After transplantation of BMSCs, the distribution of PKH26 positive cells was mainly on the damaged side in the endometrial tissues. Compared to control group, the endometrial tissue structure recovered after treatment with BMSCs. BMSCs transplantation improved the fertility of endometrial injury model rats. BMSCs decreased the area of endometrial fibrosis. The expression of integrin avβ3 and LIF in endometrium was the stronger in BMSCs treatment group than control group.

CONCLUSION

BMSCs can migrate to the endometrium and repair damaged endometrium and improve endometrium receptivity.

Injectable Mesenchymal Stem Cell-Laden Matrigel Microspheres for Endometrium Repair and Regeneration

Endometrial injury and intrauterine adhesions are increasingly reported in recent years; however, treatment options remain limited. Intravenous injection of mesenchymal stem cells (MSCs) for endometrium regeneration has limited effectiveness as the retention rate of transplanted cells is low. Hydrogel-based tissue-engineered solutions, such as MSC-seeded bioscaffolds, are reported to increase retention rates; however, a less invasive alternative is still desirable. 560-µm homogeneous Matrigel microspheres are fabricated, loading them with about 1500 MSCs and injecting them into the injured endometria of rats' uteri. This minimally invasive procedure is proved to significantly increase endometrium thickness by over onefold after 21 d (p < 0.0001) and fertility rates from 25% to 75% in impaired and repaired uteri (p < 0.001), respectively. This study provides a minimally invasive alternative to endometrium repair with the promise to establish a broad-spectrum technique for MSC transplantation.

The Effect of Sildenafil Citrate on Poor Endometrium in Patients Undergoing Frozen-Thawed Embryo Transfer following Resection of Intrauterine Adhesions: A Retrospective Study

BACKGROUND

The recent studies have shown that sildenafil citrate can enhance estrogen-induced proliferation of the endometrium in infertile women.

OBJECTIVE

This study was aimed to investigate whether sildenafil citrate could affect pregnancy outcomes in infertile women receiving frozen-thawed embryo transfer (FET) after resection of intrauterine adhesions (IUAs).

MATERIALS AND METHODS

A total of 310 subjects who met the inclusion criteria were recruited and divided into the control group (group A) and the sildenafil citrate group (or the SC group, group B). The 2 groups were, respectively, divided into 2 subgroups based on the severity of reformed adhesions: (1) group A1 (with mild IUAs) and group A2 (with moderate to severe IUAs) and (2) group B1 (with mild IUAs) and group B2 (with moderate to severe IUAs). Therapeutic effects of sildenafil citrate on the cases were evaluated after resection of IUAs during FET cycles. Endometrial thickness, endometrial pattern, and pregnancy outcomes were evaluated and compared between the 2 groups.

RESULTS

There was no significant difference in the number of embryos transferred between the 2 groups. The endometrial thickness in group B (0.80 [0.68-0.90] cm) was significantly higher than that in group A (0.73 [0.35-0.80] cm). Besides, the biochemical pregnancy rate, clinical pregnancy rate, and live birth rate (LBR) were 71.60, 50.83, and 39.17% in group B, which were significantly higher than those in group A, namely, 57.36, 34.73, and 23.68%, respectively (p < 0.05). The univariate analysis and multivariate logistic regression showed that the LBR in either subgroups of group B after vaginal sildenafil treatment was significantly higher than that in the corresponding control group (p < 0.05).

CONCLUSIONS

It was observed that the administration of sildenafil citrate during FET could effectively improve the poor endometrial conditions after FET following the resection of IUAs.

The Efficacy of Complementary and Alternative Medicine in the Treatment of Female Infertility

Female infertility is a state of fertility disorder caused by multiple reasons. The incidence of infertility for females has significantly increased due to various factors such as social pressure, late marriage, and late childbirth, and its harm includes heavy economic burden, psychological shadow, and even marriage failure. Conventional solutions, such as hormone therapy, in vitro fertilization (IVF), and embryo transfer, have the limitations of unsatisfied obstetric outcomes and serious adverse events. Currently, complementary and alternative medicine (CAM), as a new treatment for infertility, is gradually challenging the dominant position of traditional therapies in the treatment of infertility. CAM claims that it can adjust and harmonize the state of the female body from a holistic approach to achieve a better therapeutic effect and has been increasingly used by infertile women. Meanwhile, some controversial issues also appeared; that is, some randomized controlled trials (RCTs) confirmed that CAM had no obvious effect on infertility, and the mechanism of its effect could not reach a consensus. To clarify CAM effectiveness, safety, and mechanism, this paper systematically reviewed the literature about its treatment of female infertility collected from PubMed and CNKI databases and mainly introduced acupuncture, moxibustion, and oral Chinese herbal medicine. In addition, we also briefly summarized psychological intervention, biosimilar electrical stimulation, homeopathy, hyperbaric oxygen therapy, etc.

Effect of sildenafil citrate on treatment of infertility in women with a thin endometrium: a systematic review and meta-analysis

OBJECTIVE

Endometrial thickness is a prognostic factor for successful pregnancy. This meta-analysis aimed to examine the role of sildenafil citrate on infertile women with a thin endometrium.

METHODS

Two investigators independently searched the literature on sildenafil citrate and infertile women with a thin endometrium from PubMed, EMBASE, and the Cochrane Controlled Trials Register Database from inception to January 2019.

RESULTS

Nine studies involving 1452 patients were included for analysis in our study. We found that endometrial thickness in patients who received sildenafil citrate was significantly higher than that in the control group (placebo or no treatment) (weighted mean difference: 1.22; 95% confidence interval [CI]: 1.07-1.38). The radial artery resistance index was significantly lower (weighted mean difference: -0.12; 95% CI: -0.17 to -0.06), and the clinical pregnancy rate (risk ratio: 1.31; 95% CI: 1.11-1.53) and biochemical pregnancy rate (risk ratio: 1.45; 95% CI: 1.11-1.89) were significantly higher in the sildenafil citrate group compared with the control group.

CONCLUSION

Sildenafil citrate is effective in improving endometrial thickness, the clinical pregnancy rate, and the biochemical pregnancy rate in women who have a thin endometrium. This treatment is a potential therapeutic intervention for a thin endometrium.

Cell-based endometrial regeneration: current status and future perspectives

Endometrial-related disorders including Asherman's syndrome, thin endometrium, pelvic organ prolapse, and cesarean scar pregnancies can be accompanied by different symptoms such as amenorrhea, infertility, abnormal placental implantation and recurrent miscarriage. Different methods have been introduced to overcome these problems such as surgery and hormonal therapy but none of them has shown promising outcomes. On the other hand, the development of novel regenerative therapeutic strategies has opened new avenues for the treatment of endometrial-related deficiencies. In this regard, different types of scaffolds, acellular matrices and also cell therapy with adult or stem cells have been investigated for the treatment of endometrial-related deficiencies. In this paper, we review the current status of cell-based endometrium regeneration using scaffold dependent and scaffold-free methods and future perspectives in this field. Moreover, we discuss the endometrial diseases that can be candidates for cell-based treatments. Also, the cells with the potential for endometrial regeneration are explained.

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.

Relationship between temporal changes of endometrial blood flow impedance during natural and hormone replacement cycles and prediction of pregnancy during vitrified-warmed embryo transfer

AIM

This study aimed to examine the relationship between the temporal changes in endometrial blood flow impedance during natural and hormone replacement therapy (HRT) cycles and clinical outcomes of vitrified-warmed embryo transfer (ET).

METHODS

This retrospective observational cohort study included 60 women, 28 with natural, and 32 with HRT cycles, who underwent vitrified-warmed ET. Uterine radial artery resistance index (RA-RI) was measured during the natural and HRT cycles at the following time points: early follicular phase, day of the human chorionic gonadotropin injection during a natural cycle or day of progesterone administration during an HRT cycle, and day of ET.

RESULTS

The clinical pregnancy rates of the natural and HRT cycles were 32.1% and 34.4%, respectively. The RA-RI at the early follicular phase was significantly lower in the pregnant group than in the nonpregnant group with natural but not HRT cycles (p = 0.04). The odds ratio for pregnancy was 0.70 (95% confidence interval [CI], 0.52-0.95) when the RA-RI value at the early follicular phase was increased by 0.01 in the natural cycle. With the natural cycle, the area under the receiver-operating characteristic curves for the RA-RI at the early follicular phase with a threshold of 0.68 was 0.75 (95% CI, 0.57-0.93), and the positive and negative predictive values were 0.53 (95% CI, 0.37-0.59) and 0.92 (0.74-0.99), respectively.

CONCLUSION

RA-RI at the early follicular phase might be an effective and useful tool for deciding between natural or HRT cycles for vitrified-warmed ET.

Adjuvant Vaginal Use of Sildenafil Citrate in a Hormone Replacement Cycle Improved Live Birth Rates Among 10,069 Women During First Frozen Embryo Transfers

Purpose

To investigate the effects of sildenafil citrate (SC) on live birth rates (LBR) during women undergoing their first frozen embryo transfers (FET) with hormone replacement therapy (HRT).

Patients and Methods

This retrospective cohort study included a total of 10,069 infertile women with adequate endometrial thickness (≥7 mm when progesterone was initiated) in their first FET cycle with hormone replacement therapy. Women received either vaginal SC or no adjuvant during their first transfer cycle depending on patient or physician preference. In the sildenafil group, 1098 women underwent HRT FET with adjuvant vaginal use of SC, and 8971 women were included as controls. The primary outcome measure was LBR, defined as the likelihood of live birth per transfer cycle. Endometrial thickness (EMT), implantation, chemical pregnancy, clinical pregnancy, miscarriage, ongoing pregnancy, birth weight and preterm delivery (PTB) were also recorded.

Results

Baseline characteristics were comparable between the two groups. In the crude analysis, the unadjusted LBR was significantly higher in the vaginal SC group (scHRT-FET) than in the control group (HRT-FET) (40.3% vs 36.1%). After adjustment for 12 pregnancy-related confounding factors, logistic regression analysis showed that LBR remained significantly higher in the scHRT-FET group than in the HRT-FET group (adjusted odds ratio [aOR] 1.31, 95% confidence interval [CI] 1.14–1.49). Furthermore, after adjustment, the ongoing pregnancy rate was significantly higher (aOR 1.29, 95% CI 1.13–1.47), and the miscarriage rate was significantly lower (aOR 0.58, 95% CI 0.43–0.77), in the scHRT-FET group compared to the HRT-FET group. Adjuvant vaginal use of SC did not increase the endometrial thickness and had no significant effect on birth weight or PTB.

Conclusion

Adjuvant vaginal use of SC in HRT FET was associated with higher LBR and improved pregnancy outcomes in an infertile population with adequate endometrial thickness. The beneficial effect of SC may be due not to an increase in EMT but instead to improve endometrial blood flow and receptivity, which might merit clinicians’ attention for improving general IVF practices.

Beneficial effect of l-arginine in women using assisted reproductive technologies: a small-scale randomized controlled trial

This small-scale randomized controlled study aimed to examine the effect of l-arginine supplementation on the human chorionic gonadotropin (hCG)-positive rate and clinical pregnancy rate (CPR) in women undergoing assisted reproductive technology (ART) treatment for 3 months. From November 2017 to March 2018, 120 patients aged less than 40 years and planning for egg retrieval for embryo transfer were enrolled. The patients were divided into the AS2000 group (n = 36; l-arginine, 2 g; folate, 400 μg; and vitamin E, 10 mg), AS1000 group (n = 37; l-arginine, 1 g; and folate, 200 μg), and control group (n = 36). The main outcome was the hCG-positive rate or CPR in 3 months. The cumulative hCG-positive rates during the administration period were 44.2%, 54.2%, and 52.1%, and the CPRs were 39.5%, 41.7%, and 47.9% in the control, AS1000, and AS2000 groups, respectively. Odds ratios of the hCG-positive rate and CPR in the global l-arginine group (AS1000 and AS2000) versus those in the control group were 1.33 (95% confidence interval [CI], 0.62-2.90) and 1.11 (95% CI, 0.51-2.46), respectively. In the subgroup of women receiving ART because of male infertility, the hCG-positive rate and CPR were significantly increased in the l-arginine groups compared to those in the control group (13.42 [95% CI, 1.42-366.9] and 13.62 (95% CI, 1.42-367.6), respectively). Thus, arginine supplementation may be an option for women who desire pregnancy, especially those undergoing an ART program because of male infertility.

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

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

Management of a Thin Endometrium by Hysteroscopic Instillation of Platelet-Rich Plasma Into The Endomyometrial Junction: A Pilot Study

In patients whose embryo transfer has been previously canceled due to a thin endometrium, the injection of platelet-rich plasma (PRP) guided by hysteroscopy into the endomyometrial junction improves endometrial thickness and vascularity. This may well serve as a novel approach for the management of these patients. In this study, 32 patients aged between 27 and 39 years, suffering from primary or secondary infertility, were selected for hysteroscopic instillation of PRP. This cross-sectional study included a retrospective assessment of the improvement of endometrial thickness (>7 mm) on the commencement of progesterone treatment in 24 of 32 patients (75%) after hysteroscopy-guided injections of PRP into the subendometrial zone. After PRP instillation, the endometrium was 7 mm or thicker in 24 of 32 patients, and all 24 patients underwent frozen embryo transfer. Moreover, 12 of 24 patients who underwent embryo transfer conceived, whereas 10 had a clinical pregnancy with visualization of cardiac activity at 6 weeks and two had a biochemical pregnancy. Our approach of PRP injection into the subendometrial region is consistent with the histologically proven regeneration of the endometrium from the endomyometrial junction. We observed an improvement of endometrial thickness and higher pregnancy rates in cases of previously canceled embryo transfer due to a thin endometrium.

Sildenafil might impair maternal-fetal immunotolerance by suppressing myeloid-derived suppressor cells in mice

Myeloid-derived suppressor cells (MDSCs) as an important population of immune cells were found to restrain T cell function, polarize T-helper cells (Th) 1/Th2 toward Th2 response and induce regulatory T cells (Tregs), therefore enhancing the immunotolerance during pregnancy. Sildenafil has been applied for poor endometrial quality in implantation failure patients. Nevertheless, investigations have shown that sildenafil could reduce MDSCs-dependent immunosuppression. Whether sildenafil affects embryo implantation by suppressing MDSCs? To address this question, using the mice model, we investigated the amounts of immune cells in peripheral blood and endometrial cells from control group (CG), sildenafil low-dose group (LDG) and high-dose group (HDG). We found that both treatment groups displayed a marked deficiency in polymorphonuclear (PMN)-MDSCs and Th2 from mice blood and endometrium as compared to these from CG. The frequency of Tregs in endometrium from HDG was lower than those from CG. Th1/Th2 ratio in both periphery and uterus from study groups showed a significant increase as compared to those from CG. By relevance analysis, we found that the level of Tregs positively correlated with the level of PMN-MDSCs, whereas the Th1/Th2 ratio negatively correlated with the frequency of PMN-MDSCs in uterus. Moreover, there was a positive relationship between the amount of blood PMN-MDSCs and endometrial PMN-MDSCs. These results suggest that we should carefully weigh the pros and cons of using sildenafil when applied to patients with poor endometrial receptivity.

Effect of amlodipine on blood flow of preovulatory follicle in women with clomiphene resistant polycystic ovaries: a randomized controlled trial

OBJECTIVE

To detect whether amlodipine could increase pre-ovulatory follicular blood flow, thus enhancing ovulation and creating a better chance of conception in women with PCOS.

METHODS

165 women were screened of which 124 were qualified and women were equally randomized to 62 receiving clomiphene citrate and amlodipine and 62 receiving clomiphene citrate and placebo. The primary outcome was to detect if amlodipine can improve pre-ovulatory follicle blood flow studied by colour and power Doppler Pulsatility index of ovarian arteries, with drug administration. The secondary outcomes were endometrial thickness and clinical pregnancy.

RESULTS

The mean value of the ovarian arteries Pulsatility Index was significantly lower in the amlodipine group when compared to those of the placebo group (1.36 and 1.82, respectively, with P value 0.002). Mean endometrial thickness, for all women in both groups, on the day of detecting a mature follicle was significantly higher in the amlodipine group compared to the placebo group (8.99 and 7.0, respectively, with P value 0.003), and clinical pregnancy increased from 11% to 37% in the amlodipine group compared to the placebo group.

CONCLUSION

Amlodipine improves ovarian blood flow and increases the chances of conception.

TRIAL REGISTRATION

Pan African Clinical Trial Registry (http://www.pactr.org). Trial No: PAC TR201708002485292.

Cumulative Live Birth Rate in Patients With Thin Endometrium: A Real-World Single-Center Experience

Background: Studies have shown that patients with a thin endometrial thickness (EMT < 7 or 8 mm) during IVF/ICSI tend to have adverse pregnancy outcomes, and this has caused much anxiety to both patients and physicians when confronted with a thin EMT. Method: From January 2015 to December 2018, patients with a thin EMT < 7 mm on the day of hCG administration during their first GnRH agonist IVF/ICSI cycle were included. According to the hysteroscopy results, patients were classified into totally normal (Group A), normal with a specific abnormality (Group B), and adhesion before transfer (Group C). Result: For the 245 patients included, approximately 60% of the thin EMT cases were the result of an intrauterine operation. CLBR was 35.45% (67/189) in this group of patients. In regard to CLBR, there were significant differences among these three uterus condition groups irrespective of the number of oocytes retrieved (28.57 vs. 10.00 vs. 4.76%, P = 0.12 in oocyte ≤5; 61.36 vs. 44.67 vs. 23.63%, P = 0.00 in oocyte >5). In binary logistic regression analysis, age (OR = 0.09, P = 0.03), number of embryos available (OR = 1.71, P = 0.00), and uterine condition (OR = 6.77, P = 0.00 for group A; OR = 2.55, P = 0.04 for group B; Reference = group C), were significantly associated with CLBR. However, EMT and endometrial pattern had no impact on CLBR. Conclusion: An intrauterine operation was the main reason for a thin EMT. Thin EMT patients with a normal uterine cavity and endometrium had a significantly better CLBR compared with those with adhesions before transfer.

The Effect of Vaginal Sildenafil on The Outcome of Assisted Reproductive Technology Cycles in Patients with Repeated Implantation Failures: A Randomized Placebo-Controlled Trial

Background

The aim of this study was to investigate the effects of vaginal sildenafil on the outcome of patients with at least two unsuccessful in vitro fertilization/intracytoplasmic sperm injection (IVF/ICSI) attempts.

Materials and Methods

In this randomized placebo-controlled trial study, a total of 66 infertile women aged ≤38 years, with a history of normal ovarian reserve, two prior consecutive failed IVF/ICSI attempts, human chorionic gonadotropin (hCG) day endometrial thickness <7 mm in all prior IVF/ICSI cycles, normal endometrial appear- ance by either hysteroscopy, hysterosonography, or hysterosalpingography enrolled in this study. The conventional gonadotropin-releasing hormone (GnRH) protocol was used for ovarian stimulation. The patients were randomly divided into three groups: vaginal sildenafil (suppository-100 mg/daily), vaginal placebo/sildenafil (suppository-100 mg/daily), and vaginal placebo (suppository). Each patient underwent colour Doppler ultrasound on day 14 of their previous cycle to investigate any abnormalities in the uterus and adnexa. Endometrial thickness, echo pattern, uterine artery resistance, and pulsatility indices were recorded pre- and post-treatment. The primary outcome measures were implantation, chemical and clinical pregnancy rates. For data analysis, SPSS version 20 software was used. In all tests, the significance level was considered less than 0.05.

Results

There was no significant difference between three groups in endometrial thickness on the hCG injection day. The chemical pregnancy in women who received sildenafil (alone or in combination with placebo) showed a two-fold increase in comparison to the placebo group. This increase was clinically meaningful, but according to sample size, it was statistically non-significant. The results of our study showed that the implantation was higher in women who received placebo/sildenafil compared to the other groups. The abortion rate was not statistically significant among the groups.

Conclusion

Vaginal sildenafil may conceivably improve chemical pregnancy rates in repeated IVF failure patients. Further randomized clinical trials using oral or vaginal sildenafil with higher sample size are recommended (Registra- tion number: NCT03192709).

Management of thin endometrium in assisted reproduction: a clinical practice guideline from the Canadian Fertility and Andrology Society

The impact and management of thin endometrium is a common challenge for patients undergoing assisted reproduction. The objective of this Canadian Fertility and Andrology Society (CFAS) guideline is to provide evidence-based recommendations using the GRADE (Grading of Recommendations, Assessment, Development and Evaluations) framework on the assessment, impact and management of thin endometrium in assisted reproduction. The effect of endometrial thickness on pregnancy and live birth outcomes in ovarian stimulation and IVF (fresh and frozen cycles) is addressed. In addition, recommendations on the use of adjuvants to improve endometrial thickness and pregnancy outcomes are provided.

Investigation of platelet-rich plasma in increasing proliferation and migration of endometrial mesenchymal stem cells and improving pregnancy outcome of patients with thin endometrium

BACKGROUND

Platelet-rich plasma (PRP) contains abundant growth factors and is gradually used in the field of reproduction. A thin endometrium is recognized as a critical factor in embryo implantation failure. Endometrial mesenchymal stem cells (EnMSCs), which were isolated from human menstrual blood, are highly proliferative and show multiple differentiation capacity. The current study was to investigate the effect of PRP on the proliferation and migration of EnMSCs, and the effectiveness of PRP in the treatment of patients with thin endometrium.

MATERIALS AND METHODS

EnMSCs were treated with PRP in vitro, followed by measuring cell proliferation, migration, and adhesion by using CCK8, scratch, and adhesion test, respectively. Twenty patients undergoing in vitro fertilization (IVF) with refractory thin endometrium history were given PRP by infusion into the uterine cavity after the treatment of hormone replacement therapy (HRT).

RESULTS

All components of PRP significantly stimulated the growth, migration, and adhesion of EnMSCs when compared with the negative control. Cell proliferation and migration were induced by PRP in a dose-dependent manner with maximum proliferation at a 2% PRP dose. The clinical data showed that successful endometrial expansion and pregnancy were discovered in 12 patients after PRP infusion, and the pregnancy rate increased to 60%.

CONCLUSION

Intrauterine PRP infusion represents a new way for female patients with thin endometrium with poor response. This study lays the foundations for the potential treatment of thin endometrium with PRP in vivo.

Effects of growth hormone on pregnancy rates of patients with thin endometrium

PURPOSE

To investigate whether growth hormone (GH) could improve pregnancy rates of patients with thin endometrium by clinical study and laboratory experiments.

MATERIALS AND METHODS

Ninety-three patients were randomized to either the GH-received group (40) or the routine exogenous administration of estrogens control group (53) for clinical study. The human endometrial carcinoma cell line RL95-2 was used for testing the role of GH with Western blot and real-time PCR by exposure to various concentrations of GH (0.1 nM,1 nM,10 nM,100 nM).

RESULTS

Patients treated with GH had a significantly (P < 0.05) greater endometrium thickness on day 3 (7.87±0.72 vs 6.34±0.86), higher implantation rates (24.4% vs 10.5%) and greater clinical pregnancy rates (42.5% vs 18.9%) compared with the control group. No adverse events were associated with the use of GH. Administration of GH significantly up-regulated the expression of VEGF, ItgB3 and IGF-I expression in RL95-2 cells at both mRNA and protein levels (P < 0.05). AG490, an inhibitor of JAK2, nearly completely inhibited the up-regulative effect of GH through the JAK2-STAT5 pathway, and GH-induced effects could be mediated through autocrine IGF-I together with its hepatic counterpart. IGF-I mRNA was detected in the RL95-2 cells.

CONCLUSION

GH may improve pregnancy outcomes of patients with thin endometrium who undergo frozen embryo transfer by acting on human endometrial cells to promote proliferation and vascularization and to up-regulate receptivity-related molecular expression.

Autologous platelet-rich plasma infusion improves clinical pregnancy rate in frozen embryo transfer cycles for women with thin endometrium

BACKGROUND

Adequate thickness of the endometrium has been well recognized as a critical factor for embryo implantation. This was a prospective cohort study to investigate the benefits of platelet-rich plasma (PRP) for women with thin endometrium who received frozen embryo transfer (FET) program in a larger number of patients and explore the underlying mechanism.

METHODS

In this study, we investigated the effects of PRP in women with thin endometrium in FET program. 64 patients with thin endometrium (<7 mm) were recruited. PRP intrauterine infusion was given in PRP group during hormone replacement therapy (HRT) cycle in FET cycles.

RESULTS

After PRP infusion, the endometrium thickness in PRP group was 7.65 ± 0.22 mm, which was significantly thicker than that in control group (6.52 ± 0.31 mm) (P <.05). Furthermore, PRP group had lower cycle cancellation rate when compared to control group (19.05% vs. 41.18%, P <.01). The implantation rate and clinical pregnancy rate in PRP group were significantly higher than those in control group (27.94% vs 11.67%, P <.05; 44.12% vs 20%, P <.05, respectively). PRP blood contained 4 folds higher platelets and significantly greater amounts of growth factors including platelet-derived growth factor (PDGF)-AB, PDGF-BB, and transforming growth factor (TGF)-β than peripheral blood (P <.01).

CONCLUSIONS

PRP plays a positive role in promoting endometrium proliferation, improving embryo implantation rate and clinical pregnancy rate for women with thin endometrium in FET cycles.

Vasodilators for women undergoing fertility treatment

BACKGROUND

The rate of successful pregnancies brought to term has barely increased since the first assisted reproductive technology (ART) technique became available. Vasodilators have been proposed to increase endometrial receptivity, thicken the endometrium, and favour uterine relaxation, all of which could improve uterine receptivity and enhance the chances for successful assisted pregnancy.

OBJECTIVES

To evaluate the effectiveness and safety of vasodilators in women undergoing fertility treatment.

SEARCH METHODS

We searched the following electronic databases, trial registers, and websites: the Cochrane Gynaecology and Fertility Group (CGF) Specialised Register of controlled trials, the Cochrane Central Register of of Controlled Trials, via the Cochrane Register of Studies Online (CRSO), MEDLINE, Embase, PsycINFO, the Cumulative Index to Nursing and Allied Health Literature (CINAHL), Web of Knowledge, the Open System for Information on Grey Literature in Europe (OpenSIGLE), the Latin American and Caribbean Health Science Information Database (LILACS), clinical trial registries, and the reference lists of relevant articles. We conducted the search in October 2017 and applied no language restrictions.

SELECTION CRITERIA

Randomised controlled trials (RCTs) comparing vasodilators alone or in combination with other treatments versus placebo or no treatment or versus other agents in women undergoing fertility treatment.

DATA COLLECTION AND ANALYSIS

Four review authors independently selected studies, assessed risk of bias, extracted data, and calculated risk ratios (RRs). We combined study data using a fixed-effect model and assessed evidence quality using Grades of Recommendation, Assessment, Development and Evaluation Working Group (GRADE) methods. Our primary outcomes were live birth or ongoing pregnancy and vasodilator side effects. Secondary outcomes included clinical pregnancy, endometrial thickness, multiple pregnancy, miscarriage, and ectopic pregnancy.

MAIN RESULTS

We included 15 studies with a total of 1326 women. All included studies compared a vasodilator versus placebo or no treatment. We judged most of these studies as having unclear risk of bias. Overall, the quality of evidence was low to moderate for most outcomes. The main limitations were imprecision due to low numbers of events and participants and risk of bias due to unclear methods of randomisation.Vasodilators probably make little or no difference in rates of live birth compared with placebo or no treatment (RR 1.18, 95% confidence interval (CI) 0.83 to 1.69; three RCTs; N = 350; I² = 0%; moderate-quality evidence) but probably increase overall rates of side effects including headache and tachycardia (RR 2.35, 95% CI 1.51 to 3.66; four RCTs; N = 418; I² = 0%; moderate-quality evidence). Evidence suggests that if 236 per 1000 women achieve live birth with placebo or no treatment, then between 196 and 398 per 1000 will do so with the use of vasodilators.Compared with placebo or no treatment, vasodilators may slightly improve clinical pregnancy rates (RR 1.45, 95% CI 1.19 to 1.77; 11 RCTs; N = 1054; I² = 6%; low-quality evidence). Vasodilators probably make little or no difference in rates of multiple gestation (RR 1.15, 95% CI 0.55 to 2.42; three RCTs; N = 370; I² = 0%; low-quality evidence), miscarriage (RR 0.83, 95% CI 0.37 to 1.86; three RCTs; N = 350; I² = 0%; low-quality evidence), or ectopic pregnancy (RR 1.48, 95% CI 0.25 to 8.69; two RCTs; N = 250; I² = 5%; low-quality evidence). All studies found benefit for endometrial thickening, but reported effects varied (I² = 92%) and ranged from a mean difference of 0.80 higher (95% CI 0.18 to 1.42) to 3.57 higher (95% CI 3.01 to 4.13) with very low-quality evidence, so we are uncertain how to interpret these results.

AUTHORS' CONCLUSIONS

Evidence was insufficient to show whether vasodilators increase the live birth rate in women undergoing fertility treatment. However, low-quality evidence suggests that vasodilators may slightly increase clinical pregnancy rates. Moderate-quality evidence shows that vasodilators increase overall side effects in comparison with placebo or no treatment. Adequately powered studies are needed so that each treatment can be evaluated more accurately.

Novel in situ gelling vaginal sponges of sildenafil citrate-based cubosomes for uterine targeting

Sildenafil citrate (SIL), a type 5-specific phosphodiesterase inhibitor, demonstrates valuable results in the management of infertility in women; however, the absence of vaginal dosage form in addition to the associated oral adverse effects minimize its clinical performance. The present study is concerned with SIL uterine targeting following intravaginal administration via optimization of cubosomal in situ gelling sponges (CIS). An emulsification method was employed for preparation of cubosomal dispersions incorporating glyceryl monooleate as a lipid phase and poloxamer 407 as a surfactant with or without polyvinyl alcohol as a stabilizer. Cubosomes were estimated regarding entrapment efficiency (EE%), particle size, and in vitro drug release. Chitosan (2% w/w) was incorporated into the optimum formulation and then lyophilized into small sponges. For the CIS, in vivo histopathological and pharmacokinetic studies were conducted on female Wistar rats and compared with intravaginal free SIL sponges (FIS) and oral SIL solution. SIL-loaded cubosomes showed EE% ranging between 32.15 and 72.01%, particle size in the range of 150.81–446.02 nm and sustained drug release over 8 h. Histopathological study revealed a significant enlargement in endometrial thickness with congestion and dilatation of endometrial blood vessels in intravaginal CIS compared to intravaginal FIS and oral-treated groups. The pharmacokinetic study demonstrated higher AUC_0–∞ and C_max with oral administration compared to intravaginal CIS or intravaginal FIS indicating potential involvement of first uterine pass effect after intravaginal administration. Finally, intravaginal CIS could be considered as a promising platform for SIL uterine targeting with minimized systemic exposure and side effects.

Stem cell therapy in Asherman syndrome and thin endometrium: Stem cell- based therapy

The endometrium is one of the essential components of the uterus. The endometrium of human is a complex and dynamic tissue, which undergoes periods of growth and turn over during any menstrual cycle. Stem cells are initially undifferentiated cells that display a wide range of differentiation potential with no distinct morphological features. Stem cell therapy method recently has become a novel procedure for treatment of tissue injury and fibrosis in response to damage. Currently, there is massive interest in stem cells as a novel treatment method for regenerative medicine and more specifically for the regeneration of human endometrium disorder like Asherman syndrome (AS) and thin endometrium. AS also known as intrauterine adhesion (IUA) is a uterine disorder with the aberrant creation of adhesions within the uterus and/or cervix. Patients with IUA are significantly associated with menstrual abnormalities and suffer from pelvic pain. In addition, IUA might prevent implantation of the blastocyst, impair the blood supply to the uterus and early fetus, and finally result in the recurrent miscarriage or infertility in the AS patients. It has been evidenced that the transplantation of different stem cells with a diverse source in the endometrial zone had effects on endometrium such as declined the fibrotic area, an elevated number of glands, stimulated angiogenesis, the enhanced thickness of the endometrium, better formed tissue construction, protected gestation, and improved pregnancy rate. This study presents a summary of the investigations that indicate the key role of stem cell therapy in regeneration and renovation of defective parts.

Platelet-rich plasma as an adjuvant in the endometrial preparation of patients with refractory endometrium

OBJECTIVE

To improve endometrial quality and implantation rates after the administration of platelet-rich plasma in patients with refractory endometrium.

METHODS

19 patients undergoing in vitro fertilization, aged between 33 and 45 years with a history of refractory endometrium, to whom platelet rich plasma was given by infusion with a catheter into the uterine cavity on the tenth day of the hormone replacement therapy, and then 72 hours after the first administration.

RESULTS

Endometrial thicknesses >7mm was reported with the first use; and in all cases, endometrial thicknesses >9mm were evident after the second administration. The entire study group qualified for Embryo Transfer at the blastocyst stage. We had 73.7% of positive pregnancy tests, of which 26.3% yielded live births; 26.3% ongoing pregnancies; 10.5% biochemical pregnancies; 5.3% anembryonic pregnancies and 5.3% had fetal death (16 weeks).

CONCLUSIONS

Platelet-rich plasma and its biostimulation effects on the endometrial microvasculature seems to be beneficial to patients with refractory endometrium, providing an increase in endometrial receptivity and a consequent increase in implantation rates. As an autologous resource, they are easy to obtain and inexpensive. Thus, we recommend it to be included in the different protocols for endometrial preparation, including those in which a natural cycle is preferred.

Should we continue to measure endometrial thickness in modern-day medicine? The effect on live birth rates and birth weight

The evaluation of endometrial thickness (EMT) is still part of standard cycle monitoring during IVF, despite the lack of robust evidence of any value of this measurement to predict little revalidation in contemporary medical practice; other tools, however, such as endocrine profile monitoring, have become increasingly popular. The aim of this study was to reassess whether EMT affects the outcome of a fresh embryo transfer in modern-day medicine, using a retrospective, single-centre cohort of 3350 IVF cycles (2827 women) carried out between 2010 and 2014. In the multivariate regression analysis, EMT was non-linearly associated with live birth, with live birth rates being the lowest with an EMT less than 7.0 mm (21.6%; P < 0.001) and then between 7.0 mm and 9.0 mm (30.2%; P = 0.008). An EMT less than 7.0 mm was also associated with a decrease in neonatal birthweight z-scores (-0.40; 95% CI -0.69 to -0.12). In conclusion, these results reaffirm the use of EMT as a potential prognostic tool for live birth rates and neonatal birthweight in contemporary IVF, namely when considered together with other ovarian stimulation monitoring methods, such as the late-follicular endocrine profile.

Effects of Autologous Platelet-Rich Plasma on Regeneration of Damaged Endometrium in Female Rats

PURPOSE

To investigate whether autologous platelet-rich plasma (PRP) treatment can improve regeneration of the endometrium in an experimental model of ethanol-induced damage.

MATERIALS AND METHODS

Sixty female Sprague-Dawley rats were randomly assigned into three groups: control group, ethanol group, and PRP-treated group (administration of 0.25 mL of PRP into both uterine cavities 72 hours after ethanol injection). After 15 days of endometrial damage, all the animals were sacrificed during the estrous cycle, and samples were taken from the mid-uterine horn. Functional and structural recovery of the endometrium was analyzed by hematoxylin-eosin (H&E) and Masson trichrome (MT) staining, real-time polymerase chain reaction (PCR) assay, and immuno-histochemical (IHC) analyses.

RESULTS

H&E and MT staining confirmed significantly decreased fibrosis and increased cellular proliferation in the PRP-treated group, compared to the ethanol group. The endometrial areas in the ethanol and PRP-treated groups were 212.83±15.84 μm² and 262.34±12.33 μm² (p=0.065). Significantly stronger IHC expression of cytokeratin, homeobox A10 (HOXA10), vascular endothelial growth factor (VEGF), and Ki-67 was found in the PRP-treated group, compared to the ethanol group. In real-time PCR analyses, interleukin-1β mRNA was down-regulated, while c-Kit mRNA was up-regulated, in the PRP-treated group, compared to the ethanol group.

CONCLUSION

Intrauterine administration of autologous PRP stimulated and accelerated regeneration of the endometrium and also decreased fibrosis in a murine model of damaged endometrium.

Thin endometrium transcriptome analysis reveals a potential mechanism of implantation failure

Aim

Although a thin endometrium has been well recognized as a critical factor in implantation failure, little information is available regarding the molecular mechanisms. The present study investigated these mechanisms by using genome‐wide mRNA expression analysis.

Methods

Thin and normal endometrial tissue was obtained from a total of six women during the mid‐luteal phase of the menstrual cycle. The transcriptomes were analyzed with a microarray. Differentially expressed genes were classified according to Gene Ontology (GO) terms and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways.

Results

The study identified 318 up‐regulated genes and 322 down‐regulated genes in the thin endometrium, compared to the control endometrium. The GO and KEGG pathway analyses indicated that the thin endometrium possessed aberrantly activated immunity and natural killer cell cytotoxicity that was accompanied by an increased number of inflammatory cytokines, such as IFN‐γ. Various genes that were related to metabolism and anti‐oxidative stress were down‐regulated in the thin endometrium.

Conclusion

Implantation failure in the thin endometrium appears to be associated with an aberrantly activated inflammatory environment and aberrantly decreased response to oxidative stress.

The Effect of Tamoxifen on Thin Endometrium in Patients Undergoing Frozen-Thawed Embryo Transfer

Tamoxifen has played a vital role in endocrine therapy for the treatment of estrogen receptor-positive breast cancer. We examined the effect of tamoxifen in patients with a thin endometrium in frozen-thawed embryo transfer (FET) cycles and compared the improvement in endometrial thickness (EMT) and pregnancy outcomes stratified by different etiologies of thin endometrium. A total of 226 women were recruited for a new tamoxifen protocol; all had an EMT of less than 7.5 mm in previous cycles, including natural cycle (NC), hormone replacement treatment (HRT), and ovulation induction (OI) cycles. Compared with previous cycles, tamoxifen cycles showed a significantly increased EMT (from 6.11 ± 0.98 mm to 7.87 ± 1.48 mm in the NC group, from 6.24 ± 1.01 mm to 8.22 ± 1.67 mm in the HRT group, and from 6.34 ± 1.03 mm to 8.05 ± 1.58 mm in the OI group; all P < .001). Patients were further divided into 3 groups based on the causes of their thin endometrium: (1) history of intrauterine adhesion (n = 34), (2) history of uterine curettage (n = 141), and (3) polycystic ovary syndrome (PCOS; n = 51). Patients with PCOS obtained the thickest EMT (9.31 ± 1.55 mm), the lowest cycle cancellation rate (11.76%), and the highest rate of clinical pregnancy (60%) and live birth (55.56%) per transfer ( P < .001). Multivariable regression analysis showed that EMT was related to live birth (odds ratio: 1.487; 95% confidence interval: 1.172-1.887). A tamoxifen protocol improves EMT in patients after NC, HRT, and OI cycles during FET. Patients with PCOS show the most benefit from tamoxifen and achieve better pregnancy outcomes.