Granulocyte-macrophage colony-stimulating factor promotes endometrial repair after injury by regulating macrophages in mice.

Intrauterine adhesion (IUA) caused by endometrial injury is a common cause of female infertility and is challenging to treat. Macrophages play a critical role in tissue repair and cyclical endometrial regeneration. Granulocyte-macrophage colony-stimulating factor (GM-CSF) has significant reparative and anti-fibrotic effects in various tissues. However, there is limited research on the role of GM-CSF in the repair of endometrial injury and the involvement of macrophages in GM-CSF-mediated endometrial repair. In this study, using a mouse model of endometrial scratching injury, we found that GM-CSF treatment accelerated the repair of endometrial injury and improved fertility. At the molecular level, we observed that GM-CSF can downregulate the transcript levels of tumor necrosis factor (TNF) in mouse bone marrow-derived macrophages (BMDMs) stimulated by lipopolysaccharide (LPS) and upregulate the expression of Arginase-1 (Arg-1) and mannose receptor C-type 1 (MRC1). Importantly, during the early and middle stages of injury, GM-CSF increased the proportion of M1-like, M2-like, and M1/M2 mixed macrophages, while in the late stage of injury, GM-CSF facilitated a decline in the number of M2-like macrophages. These findings suggest that GM-CSF may promote endometrial repair by recruiting macrophages and modulating the LPS-induced M1-like macrophages into a less inflammatory phenotype. These insights have the potential to contribute to the development of novel therapeutic approaches for the treatment of intrauterine adhesion and related infertility.

El tratamiento hormonal es imperativo para todas las pacientes: lo antes posible y siempre / Hormone treatment is imperative for all patients: As soon as possible and always

La endometriosis se considera una enfermedad inflamatoria crónica sistémica benigna y hormonodependiente que afecta aproximadamente a un 10% de las mujeres en edad fértil. Parece que cambios innatos o adquiridos de la capacidad del endometrio para implantar, invadir y crecer en un ambiente inflamatorio con dependencia estrogénica, así como la resistencia a la progesterona son características fundamentales para la aparición y desarrollo de la endometriosis. No existe, por el momento, ningún tratamiento óptimo que consiga alcanzar los cuatro objetivos básicos del tratamiento de la endometriosis: suprimir los síntomas, restaurar la fertilidad, eliminar la endometriosis visible, y evitar la progresión de la enfermedad. Puesto que la enfermedad se considera crónica, el tratamiento médico administrado, hasta la llegada de la menopausia o de una gestación, debe ser de larga duración, efectivo y seguro. Así pues, sus objetivos reales serán la reducción o eliminación de los síntomas y/o mejoría de la fertilidad. Dadas las limitaciones y riesgos de las cirugías, el tratamiento de primera elección en la actualidad es el hormonal. Este debe individualizarse en función de la edad, paridad, deseo genésico, síntomas asociados, antecedentes patológicos y preferencias de la paciente. De forma global, existen dos tipos de tratamientos de primera elección: los estroprogestágenos en regímenes extendidos o continuos y algunos progestágenos en diferentes vías de administración (dienogest, acetato de noretisterona o desogestrel por vía oral, así como el dispositivo intrauterino de levonorgestrel de alta dosis). Los diferentes tratamientos y sus pros y contras se exponen en el artículo.(AU)

Endometriosis is nowadays considered an inflammatory chronic benign disease that responds to hormone manipulation and affects up to 10% of women in fertile age. It seems that innate or acquired changes in the endometrium ability to implant, invade and grow in an inflammatory milieu with estrogenic dependence and progesterone resistance are the responsible for new endometriosis implants and contribute to perpetuate the illness. There is, at the moment, no optimal known treatment that achieves the four basic objectives for the treatment of endometriosis: treat the symptoms, improve fertility, eliminate endometrial implants, and avoid illness progression. As is now considered a chronic condition, the prescribed medical treatment, until the patient arrives to the physiological menopause status or gets pregnant, must be considered in the long term, and must be effective and safe. Therefore, the realistic objectives of the treatment are the reduction or abolishment of symptoms and/or improve fertility. As a consequence of the limitations and risks of endometriosis surgeries, the first-line treatment is hormonal. This must be individualized according to age, parity, pregnancy desire, associated symptoms, other illnesses and patients preferences. Globally, there are two main types of first-line hormonal treatments: estroprogestins in extended or continuous regimens and some progestins in different routes of administration (dienogest, norethisterone acetate or desogestrel orally, and levonorgestrel high-dose intrauterine device). The different hormonal treatments and their pros and cons are explained in the manuscript.(AU)

Transplantation of Human Placenta Derived Mitochondria Promotes Cell Communication in Endometrium in a Murine Model of Disturbed Endometrium.

OBJECTIVES: Herein, we investigated the regenerative potential of functional mitochondria to restore endometrial injury. METHODS: The endometrium was disturbed with an intrauterine injection of 95% ethanol. Regeneration of the disturbed endometrium was achieved by transplantation of human placenta derived mitochondria followed by thrombin activated platelet rich plasma (hMTx). The transplantation method provided a biomimetic gel layer that stabilized and supported the functionality of the transplanted mitochondria to flourish regeneration of the disturbed endometrium. The presence of engrafted Rhodamine B labelled mitochondria was quantified at 12, 24, 48, and 72 h after transplantation. RESULTS: Detection of human-specific mitochondria mRNA in recipient rat uterus showed significant up-regulation of MT ATP-8, MT COX-1, MT COX -3, MT COX -2, MT ATP-6 (p = 0.009) in the hMTx treated group compared to the disturbed endometrium group. The hMTx group demonstrated showed regeneration through increased expressions of α-SMA, CK-18, CK-19, Connexin-40, E Cadherin, Claudin-1, Zona Occludin as compared with disturbed endometrium group. Experimental hMTx endometrial cells had significantly higher values of activities of NADH, NADPH, Cytochrome B5, Cytochrome P450, Complex I, Complex II, Complex III, Complex IV compared with disturbed endometrium indicating the regeneration of damaged endometrial cells at 72 h. CONCLUSIONS: Intrauterine hMTx was accounted to improve endometrial junction protein thus regeneration in the disturbed endometrium. Our Data provide the first evidence that hMTx promotes endometrial regeneration in the disturbed endometrium, paving the way for the development of a novel approach to human endometrial regeneration.

Evaluation of different rat models intrauterine adhesion models and improvement of the technique for their establishment.

Intrauterine adhesion (IUA), a leading cause of uterine infertility, is characterized by endometrial fibrosis. Implementing an appropriate animal model is essential for the research on the mechanisms of IUA. In the present study, we established and evaluated different intrauterine adhesion modeling procedures in rats to provide a reference for researchers. Rat IUA models were established by mechanical injury, 95% ethanol injection, and dual (mechanical injury with infection) injury. After two estrus cycles, the female rats were mated with sexually mature male rats, and uterine tissues were obtained on the 5th day of pregnancy. Hematoxylin and eosin staining and immunohistochemical detection of cytokeratin 19 and vimentin were performed to assess the morphology of the endometrium. Masson's trichrome staining and the expression of transforming growth factor-ß1 and collagen I were used to assess the endometrium fibrosis. The expression of integrin avß3, leukemia inhibitory factor, and homeobox gene A10 in the rat endometrium was used to evaluate the endometrial receptivity. In addition, the efficiency of embryo implantation was examined in the uterus on the 8th day of pregnancy. Our study found that mechanical injury caused by a curette can be completely repaired after two estrus cycles. However, dual injury and 95% ethanol injection can be used to establish an IUA rat model, and the dual injury is closer to the clinicpathological characteristics of IUA.

Utilidad de la histeroscopia en el manejo del sangrado uterino anorma / Usefulness of hysteroscopy in the management of abnormal uterine bleeding

La histeroscopia se considera actualmente la prueba que posibilita no solo el diagnóstico, sino también el tratamiento de enfermedad intrauterina en paciente con clínica de sangrado uterino anormal causado por anomalías estructurales, como pólipos, adenomiosis, miomas submucosos, hiperplasia endometrial o cáncer de endometrio. La miniaturización del diámetro de los histeroscopios con canal de trabajo, del minirresector bipolar y de los sistemas de morcelación histeroscópica han permitido el tratamiento en régimen ambulatorio, en ocasiones en el mismo tiempo que el diagnóstico histeroscópico, aportando mayor satisfacción, reducción riesgos quirúrgicos o derivados de la anestesia y posibilitando una rápida resolución coste-efectiva de los síntomas. En este artículo se revisa la utilidad de la histeroscopia para el diagnóstico y el tratamiento de la enfermedad estructural intrauterina causante de sangrado uterino anormal.(AU)

Hysteroscopy is currently considered the test that enables not only the diagnosis but also the treatment of intrauterine pathology in patients with symptoms of abnormal uterine bleeding caused by structural abnormalities such as polyps, adenomyosis, submucosal fibroids, endometrial hyperplasia, or endometrial cancer. The miniaturization of the diameter of hysteroscopes with working channels, the bipolar mini-resector, and the hysteroscopic morcellation systems have allowed outpatient treatment, sometimes at the same time as hysteroscopic diagnosis, providing greater satisfaction, reducing surgical and/or anaesthesia risks and enabling rapid cost-effective resolution of symptoms. This article reviews the usefulness of hysteroscopy for the diagnosis and treatment of intrauterine structural pathology causing abnormal uterine bleeding.(AU)

Metástasis de carcinoma medular de tiroides en endometrio: reporte de un caso y revisión de la literatura / Metastasis of medullary thyroid carcinoma to the endometrium: A case report and review of the literature

Las metástasis uterinas de tumores extrapélvicos son raras y, cuando el útero se ve involucrado, es usualmente por extensión directa de neoplasias de órganos adyacentes. Se presenta el caso de una mujer de 68 años con antecedente de tiroidectomía total, que concurrió con incontinencia urinaria asociada a episodios de metrorragia. Se le realizó un legrado debido a un engrosamiento endometrial y se reconoció una proliferación de células neoplásicas con núcleos ovales, cromatina en «sal y pimienta», nucléolos evidentes y moderada cantidad de citoplasma eosinófilo, las cuales resultaron positivas con CKAE1/AE3, TTF-1, CEA y calcitonina. Los hallazgos histológicos e inmunohistoquímicos correspondieron a una metástasis de un carcinoma medular de tiroides.Si bien las metástasis en el útero son extremadamente infrecuentes, el sangrado uterino anormal podría ser la única expresión clínica y se debería pensar en ello cuando los antecedentes de la paciente y los hallazgos histológicos no sean característicos de una lesión primaria.(AU)

Uterine metastases from extra pelvic tumors are rare; involvement of the uterus is usually by direct neoplastic extension from adjacent organs. We report the case of a 68-year-old woman with a history of total thyroidectomy. She presented with urinary incontinence associated with episodes of metrorrhagia. Ultrasound showed a thickened endometrium. A legrado was performed and the biopsy revealed a proliferation of neoplastic cells with oval nuclei, «salt and pepper» chromatin, evident nucleoli and a moderate amount of eosinophilic cytoplasm. These cells were positive for CKAE1 / AE3, TTF-1, CEA and calcitonin. The histological and immunohistochemical findings corresponded to a metástasis from a medullary thyroid carcinoma. Although metastatic tumors in the uterus are extremely rare, they may give rise to abnormal uterine bleeding and should be considered when the patient's history and the histological findings are not characteristic of a primary lesion.(AU)

Actualización en el manejo clínico basado en la evidencia de pólipos endometriales / Update on evidence-based clinical management of endometrial polyps

Los pólipos endometriales representan un trastorno común en la práctica habitual en ginecología. Si bien se han identificado factores de riesgo asociados a su proliferación, se desconoce la causa exacta de su aparición. En ocasiones su manejo es controvertido, siendo difícil para el clínico optar en muchos casos por una actitud expectante con seguimientos periódicos dado que el riesgo de malignidad de esta entidad no es despreciable. El objetivo del presente artículo es la realización de una revisión exhaustiva de la literatura, a partir de las principales bases de datos, sobre el diagnóstico y manejo de pólipos endometriales, así como de la fisiopatología y epidemiología, con el fin de conocer la última evidencia científica sobre esta entidad.(AU)

Endometrial polyps are a common disorder in routine gynaecological practice. Although risk factors associated with their proliferation have been identified, the exact cause of their onset is unknown. Sometimes their management is controversial, in many cases it being difficult for the clinician to opt for a wait-and-see approach with periodic follow-ups, given that the risk of malignancy with this entity is not negligible. The objective of this article was to carry out an exhaustive review of the literature, based on the main databases, on the diagnosis and management of endometrial polyps, and their pathophysiology and epidemiology, to determine the latest evidence and scientific information regarding this entity.(AU)

Endometrial scratch to increase live birth rates in women undergoing first-time in vitro fertilisation: RCT and systematic review.

BACKGROUND: In vitro fertilisation is a widely used reproductive technique that can be undertaken with or without intracytoplasmic sperm injection. The endometrial scratch procedure is an in vitro fertilisation 'add-on' that is sometimes provided prior to the first in vitro fertilisation cycle, but there is a lack of evidence to support its use. OBJECTIVES: (1) To assess the clinical effectiveness, safety and cost-effectiveness of endometrial scratch compared with treatment as usual in women undergoing their first in vitro fertilisation cycle (the 'Endometrial Scratch Trial') and (2) to undertake a systematic review to combine the results of the Endometrial Scratch Trial with those of previous trials in which endometrial scratch was provided prior to the first in vitro fertilisation cycle. DESIGN: A pragmatic, multicentre, superiority, open-label, parallel-group, individually randomised controlled trial. Participants were randomised (1 : 1) via a web-based system to receive endometrial scratch or treatment as usual using stratified block randomisation. The systematic review involved searching electronic databases (undertaken in January 2020) and clinicaltrials.gov (undertaken in September 2020) for relevant trials. SETTING: Sixteen UK fertility units. PARTICIPANTS: Women aged 18-37 years, inclusive, undergoing their first in vitro fertilisation cycle. The exclusion criteria included severe endometriosis, body mass index ≥ 35 kg/m2 and previous trauma to the endometrium. INTERVENTIONS: Endometrial scratch was undertaken in the mid-luteal phase of the menstrual cycle prior to in vitro fertilisation, and involved inserting a pipelle into the cavity of the uterus and rotating and withdrawing it three or four times. The endometrial scratch group then received usual in vitro fertilisation treatment. The treatment-as-usual group received usual in vitro fertilisation only. MAIN OUTCOME MEASURES: The primary outcome was live birth after completion of 24 weeks' gestation within 10.5 months of egg collection. Secondary outcomes included implantation, pregnancy, ectopic pregnancy, miscarriage, pain and tolerability of the procedure, adverse events and treatment costs. RESULTS: One thousand and forty-eight (30.3%) women were randomised to treatment as usual (n = 525) or endometrial scratch (n = 523) and were followed up between July 2016 and October 2019 and included in the intention-to-treat analysis. In the endometrial scratch group, 453 (86.6%) women received the endometrial scratch procedure. A total of 494 (94.1%) women in the treatment-as-usual group and 497 (95.0%) women in the endometrial scratch group underwent in vitro fertilisation. The live birth rate was 37.1% (195/525) in the treatment-as-usual group and 38.6% (202/523) in the endometrial scratch group: an unadjusted absolute difference of 1.5% (95% confidence interval -4.4% to 7.4%; p = 0.621). There were no statistically significant differences in secondary outcomes. Safety events were comparable across groups. No neonatal deaths were recorded. The cost per successful live birth was £11.90 per woman (95% confidence interval -£134 to £127). The pooled results of this trial and of eight similar trials found no evidence of a significant effect of endometrial scratch in increasing live birth rate (odds ratio 1.03, 95% confidence interval 0.87 to 1.22). LIMITATIONS: A sham endometrial scratch procedure was not undertaken, but it is unlikely that doing so would have influenced the results, as objective fertility outcomes were used. A total of 9.2% of women randomised to receive endometrial scratch did not undergo the procedure, which may have slightly diluted the treatment effect. CONCLUSIONS: We found no evidence to support the theory that performing endometrial scratch in the mid-luteal phase in women undergoing their first in vitro fertilisation cycle significantly improves live birth rate, although the procedure was well tolerated and safe. We recommend that endometrial scratch is not undertaken in this population. TRIAL REGISTRATION: This trial is registered as ISRCTN23800982. FUNDING: This project was funded by the National Institute for Health Research (NIHR) Health Technology Assessment programme and will be published in full in Health Technology Assessment; Vol. 26, No. 10. See the NIHR Journals Library website for further project information.

The endometrial scratch is a simple procedure that involves 'scratching' the lining of the womb (the endometrium). Several small studies have shown that undertaking this before the first in vitro fertilisation cycle may improve live birth rates; however, other studies have contradicted this. This large study was carried out to confirm whether or not having an endometrial scratch before the first in vitro fertilisation cycle would increase the number of women having a live birth compared with those having 'usual' in vitro fertilisation treatment (known as the 'control' group). We collected information about pregnancy, miscarriage, stillbirth, pain during the procedure and costs of treatment to find out if there were any meaningful differences. A total of 1048 women aged between 18 and 37 years were randomly allocated to the two groups, so participants had a 50% chance of having the endometrial scratch. Women were followed up throughout their pregnancy to ascertain the outcome of their in vitro fertilisation cycle. Although the live birth rate was 1.5% higher in the endometrial scratch group (38.6%) than in the control group (37.1%), the difference was not large enough to show any benefit of having the procedure. Other outcomes did not differ significantly between the two groups. However, the procedure was safe and tolerable. We found that the cost of treatment was, on average, £316 per participant higher in the group that received endometrial scratch than in the control group; the difference was not large enough to show that receiving endometrial scratch was more cost-effective. We combined the results of this trial with those of previous trials that looked to answer a similar question, and found that, overall, the endometrial scratch procedure does not enhance the chances of achieving a live birth. We conclude that endometrial scratch before first-time in vitro fertilisation does not improve the outcome of treatment, and we recommend that this procedure is not undertaken prior to a first cycle of in vitro fertilisation.

Endometrial injury concurrent with hysteroscopy increases the expression of Leukaemia inhibitory factor: a preliminary study.

OBJECTIVE: It is not known by which mechanism endometrial injury increases pregnancy rates. Leukaemia inhibitory factor (LIF) is a cytokine involved in wound healing and implantation. The aim of this study was to determine the change in endometrial LIF mRNA expression before and after mechanical injury during hysteroscopy. METHODS: Forty patients with a history of two or more unsuccessful implantations who decided to undergo hysteroscopy in the proliferative phase were divided into two equal groups: one with endometrial injury (scratching group) and the other with noninjury (control group). Endometrial sampling was conducted before injury on the patients in the scratching group, and then injury was performed with monopolar needle forceps. Only diagnostic hysteroscopy was performed on the patients in the control group. Endometrial tissues were collected using a Pipelle catheter between Days 20 and 23 of the mid-luteal phase of the next cycles in both the scratching and control groups. Endometrial LIF mRNA expression was evaluated with the use of reverse-transcription polymerase chain reactions. RESULTS: Relative changes in mRNA expression levels of the LIF gene in endometrial samples taken before and after injury were calculated using the 2-ΔΔCt method, and the fold changes obtained were compared between and within the groups. Compared with preinjury values, an 11.1-fold increase was found in postinjury LIF mRNA expression in patients with monopolar forceps injury (p < 0.001). There was a 3.9-fold significant increase in postinjury LIF mRNA levels compared with those in the control group (p < 0.02). CONCLUSIONS: The fertility-promoting effect of hysteroscopy-guided mechanical endometrial injury may be mediated by LIF mRNA.

Medroxyprogesterone acetate inhibits wound closure of human endometrial epithelial cells and stromal fibroblasts in vitro.

Mucosal integrity in the endometrium is essential for immune protection. Since breaches or injury to the epithelial barrier exposes underlying tissue and is hypothesized to increase infection risk, we determined whether endogenous progesterone or three exogenous progestins (medroxyprogesterone acetate (MPA), norethindrone (NET), and levonorgestrel (LNG)) used by women as contraceptives interfere with wound closure of endometrial epithelial cells and fibroblasts in vitro. Progesterone and LNG had no inhibitory effect on wound closure by either epithelial cells or fibroblasts. MPA significantly impaired wound closure in both cell types and delayed the reestablishment of transepithelial resistance by epithelial cells. In contrast to MPA, NET selectively decreased wound closure by stromal fibroblasts but not epithelial cells. Following epithelial injury, MPA but not LNG or NET, blocked the injury-induced upregulation of HBD2, a broad-spectrum antimicrobial implicated in wound healing, but had no effect on the secretion of RANTES, CCL20 and SDF-1α. This study demonstrates that, unlike progesterone and LNG, MPA and NET may interfere with wound closure following injury in the endometrium, potentially conferring a higher risk of pathogen transmission. Our findings highlight the importance of evaluating progestins for their impact on wound repair at mucosal surfaces.

Endometriosis. Un largo camino / Endometriosis. A life-long journey

La endometriosis es una patología hormonodependiente causada por la presencia de tejido endometrial fuera de la cavidad uterina, que induce una reacción inflamatoria crónica. Tiene una prevalencia del 10% en mujeres en edad reproductiva, pudiendo alcanzar hasta el 50% entre mujeres con infertilidad. Es una enfermedad de interés creciente debido a su prevalencia y a los avances científicos ocurridos que han permitido conocer sus diferentes fenotipos, derivando en un diagnóstico más preciso y un tratamiento con un enfoque multidisciplinar. En los últimos años han cambiado muchos paradigmas en torno a esta patología, tanto en su etiopatogenia como en su diagnóstico y tratamiento. Además, han tomado interés creciente aspectos olvidados anteriormente, como su relación con las complicaciones obstétricas y sus comorbilidades asociadas. Tratamos su impacto a lo largo de la vida de las pacientes, haciendo énfasis en nuevas perspectivas que están revolucionado la manera de entender la endometriosis.(AU)

Endometriosis is a hormone-dependent disease caused by the presence of endometrial tissue outside the uterine cavity, which induces a chronic inflammatory reaction. It has a prevalence of 10% in women of reproductive age and can reach up to 50% among women with infertility. It is a disease of growing interest due to its prevalence and to the scientific advances regarding its different phenotypes, leading to a more precise diagnosis and treatment with a multidisciplinary approach. In recent years, many paradigms around this pathology have changed, both in its aetiopathogenesis and in its diagnosis and treatment. In addition, previously forgotten aspects such as the relationship with obstetric complications and the associated comorbidities have taken on increasing interest. We discuss its impact throughout the patient's life, emphasizing new perspectives that are revolutionizing the way we understand endometriosis.(AU)

Intentional endometrial injury enhances angiogenesis through increased production and activation of MMP-9 by TNF-α and MMP-3 in a mouse model.

There have been reports of improved pregnancy rates after performing intentional endometrial injuries, also known as endometrial scratching, in patients with recurrent implantation failure. In our previous study on intentional endometrial injury, we found an increased expression of matrix metalloproteinase (MMP)-3 following induced injuries to the mice endometrium. In the current study, we further examine whether the rise in MMP-3 could contribute to increased angiogenesis. Female C57B1/6 mice were obtained at 12 weeks of age, and intentional endometrial injuries were induced mechanically in the left uterine horns. Using the appropriate media, uterine-washes were performed on the injured and uninjured (control) horns of the harvested uteri. The uterine tissues were further processed for tissue lysates, histopathology and immunohistochemistry. The results show that intentional endometrial injuries caused an increase in secreted LPA in the injured horns, which were detected in the uterine-washes. In addition, LPA induced increased production of TNF-α in human endometrial epithelial cells (hEEpCs). Furthermore, TNF-α appeared to induce differential and cell-specific upregulation of the MMPs: MMP-3 was upregulated in the epithelial (hEEpCs), while MMP-9 was upregulated in the endothelial cells (human endometrial endothelial cells; hEEnCs). The upregulation of MMP-3 appeared to be necessary for the activation of MMP-9, whose active form stimulated the formation of vessel-like structure by the hEEnCs. The results of this study suggest that there may be enhanced angiogenesis following intentional endometrial injuries, which is mediated in part by TNF-α-induced and MMP-3-activated MMP-9 production.

Endometrial injury in women undergoing in vitro fertilisation (IVF).

BACKGROUND: Implantation of an embryo within the endometrial cavity is a critical step in the process of in vitro fertilisation (IVF). Previous research has suggested that endometrial injury (also known as endometrial scratching), defined as intentional damage to the endometrium, can increase the chance of pregnancy in women undergoing IVF. OBJECTIVES: To assess the effectiveness and safety of endometrial injury performed before embryo transfer in women undergoing in vitro fertilisation (IVF) including intracytoplasmic sperm injection (ICSI) and frozen embryo transfer. SEARCH METHODS: In June 2020 we searched the Cochrane Gynaecology and Fertility Group Specialised Register, CENTRAL, MEDLINE, Embase, CINAHL, LILACS, DARE and two trial registries. We also checked the reference sections of relevant studies and contacted experts in the field for any additional trials. SELECTION CRITERIA: Randomised controlled trials comparing intentional endometrial injury before embryo transfer in women undergoing IVF, versus no intervention or a sham procedure. DATA COLLECTION AND ANALYSIS: We used standard methodological procedures recommended by Cochrane. Two independent review authors screened studies, evaluated risk of bias and assessed the certainty of the evidence by using GRADE (Grading of Recommendation, Assessment, Development and Evaluation) criteria. We contacted and corresponded with study investigators as required. Due to the high risk of bias associated with many of the studies, the primary analyses of all review outcomes were restricted to studies at a low risk of bias for selection bias and other bias. Sensitivity analysis was then performed including all studies. The primary review outcomes were live birth and miscarriage. MAIN RESULTS: Endometrial injury versus control (no procedure or a sham procedure) A total of 37 studies (8786 women) were included in this comparison. Most studies performed endometrial injury by pipelle biopsy in the luteal phase of the cycle before the IVF cycle. The primary analysis was restricted to studies at low risk of bias, and included eight studies. The effect of endometrial injury on live birth is unclear as the result is consistent with no effect, or a small reduction, or an improvement (odds ratio (OR) 1.12, 95% confidence interval (CI) 0.98 to 1.28; participants = 4402; studies = 8; I2 = 15%, moderate-certainty evidence). This suggests that if the chance of live birth with IVF is usually 27%, then the chance when using endometrial injury would be somewhere between < 27% and 32%. Similarly, the effect of endometrial injury on clinical pregnancy is unclear (OR 1.08, 95% CI 0.95 to 1.23; participants = 4402; studies = 8; I2 = 0%, moderate-certainty evidence). This suggests that if the chance of clinical pregnancy from IVF is normally 32%, then the chance when using endometrial injury before IVF is between 31% and 37%. When all studies were included in the sensitivity analysis, we were unable to conduct meta-analysis for the outcomes of live birth and clinical pregnancy due to high risk of bias and statistical heterogeneity. Endometrial injury probably results in little to no difference in chance of miscarriage (OR 0.88, 95% CI 0.68 to 1.13; participants = 4402; studies = 8; I2 = 0%, moderate-certainty evidence), and this result was similar in the sensitivity analysis that included all studies. The result suggests that if the chance of miscarriage with IVF is usually 6.0%, then when using endometrial injury it would be somewhere between 4.2% and 6.8%. Endometrial injury was associated with mild to moderate pain (approximately 4 out of 10), and was generally associated with some minimal bleeding. The evidence was downgraded for imprecision due to wide confidence intervals and therefore all primary analyses were graded as moderate certainty. Higher versus lower degree of injury Only one small study was included in this comparison (participants = 129), which compared endometrial injury using two different instruments in the cycle prior to the IVF cycle: a pipelle catheter and a Shepard catheter. This trial was excluded from the primary analysis due to risk of bias. In the sensitivity analysis, all outcomes reported for this study were graded as very-low certainty due to risk of bias, and as such we were not able to interpret the study results. AUTHORS' CONCLUSIONS: The effect of endometrial injury on live birth and clinical pregnancy among women undergoing IVF is unclear. The results of the meta-analyses are consistent with an increased chance, no effect and a small reduction in these outcomes. We are therefore uncertain whether endometrial injury improves the chance of live birth or clinical pregnancy in women undergoing IVF. Endometrial injury does not appear to affect the chance of miscarriage. It is a somewhat painful procedure associated with a small amount of bleeding. In conclusion, current evidence does not support the routine use of endometrial injury for women undergoing IVF.

Adult stem cells in endometrial regeneration: Molecular insights and clinical applications.

Endometrial damage is an important cause of female reproductive problems, manifested as menstrual abnormalities, infertility, recurrent pregnancy loss, and other complications. These conditions are collectively termed "Asherman syndrome" (AS) and are typically associated with recurrent induced pregnancy terminations, repeated diagnostic curettage and intrauterine infections. Cancer treatment also has unexpected detrimental side effects on endometrial function in survivors independently of ovarian effects. Endometrial stem cells act in the regeneration of the endometrium and in repair through direct differentiation or paracrine effects. Nonendometrial adult stem cells, such as bone marrow-derived mesenchymal stem cells and umbilical cord-derived mesenchymal stem cells, with autologous and allogenic applications, can also repair injured endometrial tissue in animal models of AS and in human studies. However, there remains a lack of research on the repair of the damaged endometrium after the reversal of tumors, especially endometrial cancers. Here, we review the biological mechanisms of endometrial regeneration, and research progress and challenges for adult stem cell therapy for damaged endometrium, and discuss the potential applications of their use for endometrial repair after cancer remission, especially in endometrial cancers. Successful application of such cells will improve reproductive parameters in patients with AS or cancer. Significance: The endometrium is the fertile ground for embryos, but damage to the endometrium will greatly impair female fertility. Adult stem cells combined with tissue engineering scaffold materials or not have made great progress in repairing the injured endometrium due to benign lesions. However, due to the lack of research on the repair of the damaged endometrium caused by malignant tumors or tumor therapies, the safety and effectiveness of such stem cell-based therapies need to be further explored. This review focuses on the molecular insights and clinical application potential of adult stem cells in endometrial regeneration and discusses the possible challenges or difficulties that need to be overcome in stem cell-based therapies for tumor survivors. The development of adult stem cell-related new programs will help repair damaged endometrium safely and effectively and meet fertility needs in tumor survivors.

Endometrial injury for pregnancy following sexual intercourse or intrauterine insemination.

BACKGROUND: Intentional endometrial injury is being proposed as a technique to improve the probability of pregnancy in women undergoing assisted reproductive technologies (ART) such as in vitro fertilisation (IVF). Endometrial injury is often performed by pipelle biopsy and is a common gynaecological procedure with established safety. However, it causes a moderate degree of discomfort/pain and requires an additional pelvic examination. The effectiveness of this procedure outside of ART, in women or couples attempting to conceive via sexual intercourse or with intrauterine insemination (IUI), remains unclear. OBJECTIVES: To assess the effectiveness and safety of intentional endometrial injury performed in infertile women or couples attempting to conceive through sexual intercourse or intrauterine insemination (IUI). SEARCH METHODS: The Cochrane Gynaecology and Fertility Group Specialised Register, CENTRAL, MEDLINE, Embase, PsycINFO, CINAHL, LILACS, ISI Web of Knowledge, and clinical trial registries were searched from inception to 21 May 2020, as were conference abstracts and reference lists of relevant reviews and included studies. SELECTION CRITERIA: We included randomised controlled trials (RCTs) that evaluated any kind of intentional endometrial injury in women planning to undergo IUI or attempting to conceive spontaneously (with or without ovarian stimulation (OS)) compared to no intervention, a mock intervention, or intentional endometrial injury performed at a different time or to a higher/lower degree. DATA COLLECTION AND ANALYSIS: We used standard methodological procedures recommended by Cochrane. Primary outcomes were live birth/ongoing pregnancy and pain experienced during the procedure. Due to high risk of bias associated with many of the studies, primary analyses of all review outcomes were restricted to studies at low risk of bias. Sensitivity analysis including all studies was then performed. MAIN RESULTS: We included 23 RCTs (4035 women). Most of these studies included women with unexplained infertility. Intentional endometrial injury versus either no intervention or a sham procedure The primary analysis was restricted to studies at low risk of bias, which left only one study included. We are uncertain whether endometrial injury has an effect on the probability of live birth, as only one study is included in the analysis and the confidence interval is wide (risk ratio (RR) 1.11, 95% confidence interval (CI) 0.78 to 1.59; 1 RCT, 210 participants). Evidence suggests that if the chance of live birth with no intervention/a sham procedure is assumed to be 34%, then the chance with endometrial injury would be 27% to 55%. When all studies were included in the sensitivity analysis, we were uncertain whether endometrial injury improves live birth/ongoing pregnancy, as the evidence was of very low quality (RR 1.71, 95% CI 1.32 to 2.21; 8 RCTs, 1522 participants; I² = 16%). Evidence suggests that if the chance of live birth/ongoing pregnancy with no intervention/a sham procedure is assumed to be 13%, then the chance with endometrial injury would be 17% to 28%. A narrative synthesis conducted for the other primary outcome of pain during the procedure included studies measuring pain on a zero-to-ten visual analogue scale (VAS) or grading pain as mild/moderate/severe, and showed that most often mild to moderate pain was reported (6 RCTs, 911 participants; very low-quality evidence). Higher versus lower degree of intentional endometrial injury Evidence was insufficient to show whether there is a difference in ongoing pregnancy rates (RR 1.29, 95% CI 0.71 to 2.35; 1 RCT, 332 participants; low-quality evidence) between hysteroscopy with endometrial injury and hysteroscopy alone. Evidence suggests that if the chance of ongoing pregnancy with hysteroscopy alone is 10%, then the chance with hysteroscopy with endometrial injury would be 7% to 24%. This study did not report the primary outcomes of live birth and pain during the procedure. Timing of intentional endometrial injury Four trials compared endometrial injury performed in the cycle before IUI to that performed in the same cycle as IUI. None of these studies reported the primary outcomes of live birth/ongoing pregnancy and pain during the procedure. One study compared endometrial injury in the early follicular phase (EFP; Day 2 to 4) to endometrial injury in the late follicular phase (LFP; Day 7 to 9), both in the same cycle as IUI. The primary outcome live birth/ongoing pregnancy was not reported, but the study did report the other primary outcome of pain during the procedure assessed by a zero-to-ten VAS. The average pain score was 3.67 (standard deviation (SD) 0.7) when endometrial injury was performed in the EFP and 3.84 (SD 0.96) when endometrial injury was performed in the LFP. The mean difference was -0.17, suggesting that on average, women undergoing endometrial injury in the EFP scored 0.17 points lower on the VAS as compared to women undergoing endometrial injury in the LFP (95% CI -0.48 to 0.14; 1 RCT, 110 participants; very low-quality evidence). AUTHORS' CONCLUSIONS: Evidence is insufficient to show whether there is a difference in live birth/ongoing pregnancy between endometrial injury and no intervention/a sham procedure in women undergoing IUI or attempting to conceive via sexual intercourse. The pooled results should be interpreted with caution, as the evidence was of low to very low quality due to high risk of bias present in most included studies and an overall low level of precision. Furthermore, studies investigating the effect of timing of endometrial injury did not report the outcome live birth/ongoing pregnancy; therefore no conclusions could be drawn for this outcome. Further well-conducted RCTs that recruit large numbers of participants and minimise bias are required to confirm or refute these findings. Current evidence is insufficient to support routine use of endometrial injury in women undergoing IUI or attempting to conceive via sexual intercourse.

Uterine Scarring Leads to Adverse Pregnant Consequences by Impairing the Endometrium Response to Steroids.

Uterine surgical scarring is an increasing risk factor for adverse pregnant consequences that threaten fetal-maternal health. The detailed molecular features of scar implantation remain largely unknown. We aim to study the pathologic features of uterine surgical scarring and the mechanisms of compromised pregnancy outcomes of scar implantation. We generated a mouse model of uterine surgical scarring with a uterine incision penetrating the myometrium to endometrium to examine the pathologic changes and transcriptome profiles of uterine scarring at various postsurgery (PS) time points, as well as features of the feto-maternal interface during scar implantation. We found that uterine surgical scar recovery was consistently poor at PS3 until PS90, as shown by a reduced number of endometrial glands, inhibition of myometrial smooth muscle cell growth but excessive collagen fiber deposition, and massive leukocyte infiltration. Transcriptome annotation indicated significant chronic inflammation at the scarring site. At the peri-implantation and postimplantation stages, abnormal expression of various steroid-responsive genes at the scarring site was in parallel with lumen epithelial cell hyperplasia, inappropriate luminal closure, and disorientation of the implanted embryo, restricted stromal cell proliferation, and defective decidualization. High embryonic lethality (around 70%) before E10.5 was observed, and the small amount of survival embryos at E10.5 exhibited restricted growth and aberrant placenta defects including overinvasion of trophoblast cells into the decidua and insufficient fetal blood vessel branching in the labyrinth. The findings indicate that chronic inflammation and compromised responses to steroids in uterine scar tissues are the pivotal molecular basis for adverse pregnancy consequences of scar implantation.

Adenomyosis in mice resulting from mechanically or thermally induced endometrial-myometrial interface disruption and its possible prevention.

RESEARCH QUESTION: Do uterine procedures potentially disrupting the endometrial-myometrial interface (EMI) induce adenomyosis? DESIGN: Six prospective, randomized controlled experiments were conducted involving a total of 106 female BALB/c and 12 female C57BL/6 mice. The incidence of adenomyosis was evaluated in these two strains of mouse after mechanically induced EMI disruption (EMID), or thermally induced EMID using electrocoagulation of different intensities. Finally, the incidence was evaluated in mice that had received perioperative administration of aprepitant (an NK1R inhibitor), propranolol (a beta-blocker) or vehicle. Body weight, hot plate latency and grade of myometrial infiltration were evaluated. Histology, immunohistochemistry and histochemistry analyses were also performed. RESULTS: Mechanical injury to the EMI caused EMID. Adenomyosis developed in the majority of mice in the EMID groups 3 months after mechanically induced EMID but did not develop in the control group (83.3% in C57BL/6 mice, P = 0.015; 100% in BALB/c mice, P = 0.0002). With thermally induced EMID, adenomyosis was found in 30% of the EMID mice 10 weeks later, but the incidence increased to 66.7% if the extent of EMID damage was increased. In mice with perioperative administration of aprepitant or propranolol, the incidence of adenomyosis was reduced from 100% to 58.3% (both P = 0.00034). CONCLUSIONS: This study provides the first piece of experimental evidence that EMID resulting from iatrogenic uterine procedures can substantially increase the risk of developing adenomyosis, with the risk in proportion to the severity of disruption. More intriguingly, perioperative administration of an NK1R antagonist or beta-blocker significantly reduced the risk of developing adenomyosis.

Transplantation of Human Adipose Stem Cells Using Acellular Human Amniotic Membrane Improves Angiogenesis in Injured Endometrial Tissue in a Rat Intrauterine Adhesion Model.

Endometrial injury resulting in intrauterine adhesion is associated with extensive damage to the regenerative basal layer of the endometrium and represents a major therapeutic challenge. Human adipose stem cells (hASCs) hold promise for future clinical use in the individualized therapy of injured endometrial tissue. Here, we observed that the use of the acellular human amniotic membrane (AHAM) significantly increased the expression of angiogenic factors, including angiogenin (ANG) and vascular endothelial growth factor (VEGF), in hASCs in vitro. The three-dimensional engineered hASC-AHAM grafts significantly increased the endometrial receptivity, as increased endometrial thickness, greater numbers of endometrial glands, and higher protein levels of leukemia inhibitory factor were observed in injured endometrial tissue that was treated with these grafts compared to those detected in injured endometrial tissue that was treated with AHAM alone. In addition, the hASC-AHAM grafts significantly increased the vascular density in the injured endometrial tissue in rats, when transplanted into an injured uterine cavity. Using the EGFP+-hASC-AHAM grafts for transplantation, we confirmed that the hASCs maintained higher protein levels of ANG and VEGF in the injured uterine cavity in vivo. The results of this study suggest that the ability of the engineered hASC-AHAM grafts to repair injured endometrial tissue may be associated with their ability to promote angiogenesis through the upregulated expression of angiogenic factors in hASCs. These findings may support individualized stem cell-based therapy for endometrial disease using bioartificial grafts.

Endometrial scratch injury with office hysteroscopy before IVF/ICSI: A randomised controlled trial.

OBJECTIVE: Endometrial scratch injury (ESI) has been proposed to improve endometrial receptivity and thereby increase implantation rates in assisted reproductive technology (ART) treatment. ESI has been widely incorporated into clinical practice despite inconclusive evidence of its effect on reproductive outcomes. We aimed to assess pregnancy and live birth rates in subfertile women receiving ESI before IVF treatment in comparison to controls. STUDY DESIGN: This was a randomised controlled trial (RCT) with no blinding of participants, investigators or health care personnel. Women in ART treatment were allocated to either office hysteroscopy with ESI (ESI group) or no intervention (control group). In total 184 women in IVF/ICSI treatment with minimum one previous failed IVF/ICSI cycle, were included in the final analysis. The primary outcome was positive serum hCG (s-hCG). Secondary outcomes were ongoing pregnancy and live birth rate. Only per-protocol analyses were performed as all patients included at one centre had to be excluded. The trial is registered at ClinicalTrials.gov, NCT01743391. RESULTS: Our results showed a non-significant increase in positive s-hCG (OR 1.23, 95 % CI (0.65-2.33)), ongoing pregnancy (OR 1.52, 95 % CI (0.73-3.17)), and live birth rates (OR 1.69, 95 % CI (0.78-3.64)) per randomised woman between the ESI and the control group. CONCLUSION: We observed no significant differences in positive s-hCG or other reproductive outcomes in the ESI vs. the control group. While the crude estimates of positive reproductive outcomes were higher in the ESI group, statistical significance was not reached, and the study was not powered to show smaller differences. However, data from this study will be re-evaluated in the context of an individual participant data meta-analysis (IPD-MA) of RCTs on ESI.

Endometrial scratching for infertility: The never-ending story.

Infertility, defined as the absence of spontaneous conception after 12 months of unprotected sexual intercourses, is a major public health issue. It is estimated that up to 15% of couples suffer from infertility and that most of them will refer for counselling to infertility specialists. Concurrently, the demands for assisted reproduction techniques are steadily increasing worldwide. Endometrial scratching is an intentional endometrial injury offered to infertile women with the purpose of enhancing endometrial receptivity before intrauterine insemination or embryo transfer. Endometrial scratching is a simple and low-cost procedure that consists in a voluntary mechanical disruption of endometrial lining, with minor patients' discomfort. Whilst the data about the effectiveness of endometrial scratching in intrauterine insemination is low but coherent, there is a great deal of confusion about the role of endometrial scratching before IVF-embryo transfer cycles. The aim of this commentary is to summarize the current evidence about the effectiveness of endometrial scratching before assisted reproduction techniques and future perspectives about the use of this technique in infertile women.