浜谷 敏生

Purpose: Since 1986, the Japan Society of Obstetrics and Gynecology assisted reproductive technology (ART) registry system has collected data on national ART use and outcomes trends in Japan. Herein, we describe the characteristics and outcomes of ART cycles registered during 2020 and compare the results with those from 2019. Methods and Results: In 2020, 621 ART facilities participated in the registration. The total number of registered cycles was 449 900, and there were 60 381 live births, which decreased from the previous year (1.79% and 0.36% decrease, respectively). The number of freeze-all in vitro fertilization (IVF) and intracytoplasmic sperm injection (ICSI) cycles increased in 2020, and the number of neonates born was 2282 for IVF-embryo transfer (ET) cycles and 2596 for ICSI cycles, which had decreased from the previous year. Frozen–thawed ET (FET) cycles had slightly increased from 2019 (0.04%). In 2020, 215 285 FET cycles were conducted, resulting in 76 196 pregnancies and 55 503 neonates. Single ET was performed in 81.6% of fresh transfers and 85.1% of frozen–thawed cycles, respectively, resulting in over 97% singleton pregnancies/livebirths rates. Conclusion: Despite the COVID-19 pandemic during 2020, the overall number of ART cycles and neonates born demonstrated only a slight decrease in 2020 compared with 2019.

AIM: This study aimed to clarify the impact of coronavirus disease 2019 on gynecology practice in Japan, in particular, on surgeries for benign gynecological diseases. METHODS: An online questionnaire was distributed to 966 facilities in Japan, including core facilities, facilities participating in perinatal and gynecologic oncology registries, and facilities certified for training by the Japanese Society of Obstetrics and Gynecology Endoscopy. The number of surgeries performed was compared between 2019 and 2020, when the novel coronavirus disease was prevalent. RESULTS: Five hundred and eighty (58.2%) facilities responded. The total number of surgeries decreased from 129 648 in 2019 to 118 565 in 2020, by 8.5%, for all surgical procedures. However, there was a clear increase in the number of robotic surgeries performed in 2020 compared to that in 2019 for all populations. The number of total hysterectomies decreased markedly from 15 385 in 2019 to 12 531 in 2020, a fall of 10.1%. CONCLUSIONS: The number of surgeries for benign gynecological diseases decreased by 8.5% in 2020 compared to that in 2019. This value is among the lowest in the world.

Abstract Objective To generate an effective embryo prediction model and identify a non-invasive evaluation method by analyzing microRNAs (miRNAs) in embryo culture medium. Design Analysis of microRNA profiles from spent culture medium of blastocysts with good morphology that did or did not result in pregnancy. Setting Clinical and experimental research. Patients Sixty patients who underwent thawed embryo transfer of blastocysts after intracytoplasmic sperm injection. Intervention(s) None. Main outcome measure(s) The association of miRNA abundance levels secreted by blastocysts in culture medium and implantation success. Results Our RNA sequencing analysis found a total of 53 differentially expressed miRNAs in the culture media of pregnancy and non-pregnancy groups. Twenty-one miRNAs were analyzed for their potential to predict implantation success. Eight miRNAs (hsa-miR-191-5p, hsa-miR-320a, hsa-miR-92a-3p, hsa-miR-509-3p, hsa-miR-378a-3p, hsa-miR-28-3p, hsa-miR-512-5p, and hsa-miR-181a-5p) were further extracted from the results of a logistic regression analysis of qPCR Ct values. A prediction model for high-quality blastocysts was generated using the eight miRNAs, with an average accuracy of 0.82 by 5-fold cross validation. Conclusion We isolated blastocyst miRNAs that may predict implantation success and created a model to predict viable embryos. Increasing the number of investigated cases and further studying the effect of each miRNA on embryonic development is needed to refine the miRNA-based predictive model.

PURPOSE: In 2017, the first guidelines for fertility preservation in cancer patients were published in Japan. However, the impact of the guidelines remains unknown. Therefore, the authors conducted a nationwide survey on cryopreservation procedures in the period from shortly before to after publication of the guidelines (2016-2019) and compared the results with our previous survey (2011-2015). The authors also surveyed reproductive specialists' awareness of the guidelines and implementation problems. METHODS: The authors sent a questionnaire to 618 assisted reproductive technology facilities certified by the Japanese Society of Obstetrics and Gynecology. RESULTS: The authors received responses from 395 institutions (63.8%). Among them, 144 institutions conducted cryopreservation for cancer patients (vs. 126 in 2011-2015) and performed 2537 embryo or oocyte and 178 ovarian tissue cryopreservation procedures (vs. 1085 and 122, respectively). Compared with the previous period, indications were more varied and protocols for controlled ovarian stimulation were more standardized. Reproductive specialists' interest in oncofertility was high, but many reported three main difficulties: selecting a treatment method, storing samples in the long term, and securing the necessary human resources. CONCLUSIONS: The practice of fertility preservation in cancer patients in Japan has been considerably affected by the first Japanese guidelines.

副腎皮質過形成(congenital adrenal hyperplasia:CAH)およびAZF遺伝子の欠失は、いずれも非閉塞性無精子症(NOA)の原因となりうる遺伝子異常である。今回我々は、CAHとAZFc部分欠失を合併した男性不妊症の事例に対して、精巣内精子採取術(TESE)および顕微授精(ICSI)により妊娠に至った事例を経験したので報告する。症例は、41歳男性と38歳女性の夫婦である。夫はCAHと診断されステロイド補充療法が実施されたものの、射出精液中に運動精子が認められず、NOAが疑われた。染色体検査およびAZF遺伝子検査がなされた結果、AZFcの部分欠失を認めた。以上を踏まえてTESEおよびICSIにより妊娠が成立したが、児は子宮内胎児死亡に至った。CAHとAZF遺伝子欠失とを原因とするNOAの事例においてもTESEが有用であることが示唆された。(著者抄録)

Purpose: Since 2007, the Japan Society of Obstetrics and Gynecology (JSOG) has collected cycle-based data for assisted reproductive technology (ART) in an online registry. Here, we present the characteristics and treatment outcomes of ART cycles registered during 2018. Methods: The Japanese ART registry consists of cycle-specific information for all ART treatment cycles implemented at 621 participating facilities. We conducted descriptive analyses for such cycles registered for 2018. Results: In total, 454 893 treatment cycles and 56 979 neonates were reported in 2018: both increased from 2017. The mean maternal age was 38.0 years (standard deviation ± 4.7). Of 247 402 oocyte retrievals, 118 378 (47.8%) involved freeze-all-embryos cycles; fresh embryo transfer (ET) was performed in 50 463 cycles: a decreasing trend since 2015. A total of 199 914 frozen-thawed ET cycles were reported, resulting in 69 357 pregnancies and 49 360 neonates born. Single ET (SET) was performed in 82.2% of fresh transfers and 83.4% of frozen-thawed cycles, with singleton pregnancy/live birth rates of 97.2%/97.2% and 97.0%/97.2%, respectively. Conclusions: Total ART cycles and subsequent live births increased in 2018. SET was performed in over 80% of cases, and the mode of ET has shifted continuously from using fresh embryos to frozen-thawed ones compared with previous years.

＜文献概要＞早期子宮体癌や子宮内膜異型増殖症(AEH)に対する妊孕性温存療法の適応は,子宮に限局し,筋層浸潤を伴わないIA期相当の子宮体癌でかつ類内膜癌G1,またはAEHであり,高用量酢酸メドロキシプロゲステロン(MPA)400〜600mg/日の内服を行う。病理学的に病変消失を確認したのちは月経発来を誘導したうえで生殖専門医へ紹介し,適切な不妊治療を早急に開始することが肝要である。MPA療法後は再発リスクが高いために,積極的に生殖補助医療を実施し,早期の妊娠成立を目指すべきである。また,不妊治療中も再発の可能性に留意し,子宮内膜生検などの評価を定期的に施行しなければならない。

Aim: Women undergoing infertility treatment often need to balance work and fertility treatment. Therefore, we evaluated the quality of life (QOL) and impact of infertility treatment on Japanese working women and their careers. Methods: We conducted an online questionnaire at 18 clinics in Japan. Responses were collected from 835 women, 713 of whom were working. The participants were divided into three groups based on treatment stage. Data were collected using the FertiQoL and an original questionnaire created by the authors. The Mann–Whitney U test and a multinomial logistic analysis were used. Results: Approximately 90% of the participants felt that treatment could hinder their work and 8% had quit their jobs. Low QOL was associated with sadness and despair due to infertility and mood disorders, disruptions to life and work, and the complicated medications and procedures involved in treatment. Social isolation and the effect of fertility treatment on daily life and work strongly hindered the careers of working women in the third stage of treatment (in vitro fertilization and intracytoplasmic sperm injection). Approximately 70% of the participants required support to subsidize treatment costs and sought shorter working hours and flextime systems. Only 55% informed their workplaces about the fertility treatment, but about 70% easily gained understanding by informing them. Conclusions: For many working women, infertility treatment posed barriers to their careers, which could explain the low QOL. Urgent introduction of a support system is necessary in Japan, and understanding and social acceptance of infertility appears to be important.

Purpose: The Japan Society of Obstetrics and Gynecology (JSOG) has collected cycle-based assisted reproductive technology (ART) data in an online registry since 2007. Herein, we present the characteristics and treatment outcomes of ART cycles registered during 2017. Methods: We collected cycle-specific information for all ART cycles implemented at participating facilities and performed descriptive analysis. Results: In total, 448,210 treatment cycles and 56,617 neonates (1 in 16.7 neonates born in Japan) were reported in 2017, increased from 2016; the number of initiated fresh cycles decreased for the first time ever. The mean patient age was 38.0 years (standard deviation 4.6). A total 110,641 of 245,205 egg retrieval cycles (45.1%) were freeze-all cycles; fresh embryo transfer (ET) was performed in 55,720 cycles. A total 194,415 frozen-thawed ET cycles were reported, resulting in 66,881 pregnancies and 47,807 neonates born. Single ET (SET) was performed in 81.8% of fresh transfers and 83.4% of frozen cycles, with singleton pregnancy/live birth rates of 97.5%/97.3% and 96.7%/96.6%, respectively. Conclusions: Total ART cycles and subsequent live births increased continuously in 2017, whereas the number of initiated fresh cycles decreased. SET was performed in over 80% of cases, and ET shifted from using fresh embryos to frozen ones.

© 2019 The Authors Zygotic genome activation (ZGA) begins after fertilization and is essential for establishing pluripotency and genome stability. However, it is unclear how ZGA genes prevent mitotic errors. Here we show that knockout of the ZGA gene Zscan5b, which encodes a SCAN domain with C2H2 zinc fingers, causes a high incidence of chromosomal abnormalities in embryonic stem cells (ESCs), and leads to the development of early-stage cancers. After irradiation, Zscan5b-deficient ESCs displayed significantly increased levels of γ-H2AX despite increased expression of the DNA repair genes Rad51l3 and Bard. Re-expression of Zscan5b reduced γ-H2AX content, implying a role for Zscan5b in DNA damage repair processes. A co-immunoprecipitation analysis showed that Zscan5b bound to the linker histone H1, suggesting that Zscan5b may protect chromosomal architecture. Our report demonstrates that the ZGA gene Zscan5b is involved in genomic integrity and acts to promote DNA damage repair and regulate chromatin dynamics during mitosis. In this article, Yamada and colleagues show that Zscan5b deficiency increases DNA stress, compromises chromosomal structure during mitosis, and leads to the development of early-stage cancers. Zscan5b deficiency may offer a murine model of human chromosomal breakage syndromes.

© 2018, United States & Canadian Academy of Pathology. Tetraspanin CD9 is essential for sperm–egg fusion and also contributes to uterine repair through microexosome formation. Microexosomes share CD9 with exosomes and are released from eggs and uterine epithelial cells. However, the mechanism for the formation of microexosomes remains unknown. To address this issue, we examined membrane localization and extracellular release of CD9 proteins using uterine epithelial cells and secretions in mice and humans. In mice, CD9 localized predominantly on the basal region of the plasma membrane and relocated to the apical region upon embryo implantation. Furthermore, extracellular CD9 proteins were detected in uterine secretions of mice and women undergoing infertility treatment, but were below detectable levels in supernatants of pluripotent stem cells. Ultrastructural analysis demonstrated that membrane projections were shortened and the number of mitochondria was reduced in uterine epithelial cells lacking Cd9 genes. Our results suggest that CD9 repositioning and release affect both membrane structures and mitochondrial state in the uterus, and contribute to female fertility.

Reproductive capacity in women starts to decline beyond their mid-30s and pregnancies in older women result in higher rates of miscarriage with aneuploidy. Age-related decline in fertility is strongly attributed to ovarian aging, diminished ovarian reserves, and decreased developmental competence of oocytes. In this review, we discuss the underlying mechanisms of age-related decline in oocyte quality, focusing on oxidative stress (OS) in oocytes. The primary cause is the accumulation of spontaneous damage to the mitochondria arising from increased reactive oxygen species (ROS) in oocytes, generated by the mitochondria themselves during daily biological metabolism. Mitochondrial dysfunction reduces ATP synthesis and influences the meiotic spindle assembly responsible for chromosomal segregation. Moreover, reproductively aged oocytes produce a decline in the fidelity of the protective mechanisms against ROS, namely the ROS-scavenging metabolism, repair of ROS-damaged DNA, and the proteasome and autophagy system for ROS-damaged proteins. Accordingly, increased ROS and increased vulnerability of oocytes to ROS lead to spindle instability, chromosomal abnormalities, telomere shortening, and reduced developmental competence of aged oocytes.

© 2018 The Authors Mitochondria are the powerhouses of eukaryotic cells and their positioning contributes to fertilization and early developmental processes. We report that sperm fusion triggers Ca2+ oscillations and mitochondrial movement toward fused sperm (mitochondrial chemotaxis) in mouse eggs. Mitochondria functioned in Ca2+ storage and were colocalized with endoplasmic reticulum (ER) during Ca2+ oscillations. Mitochondria then moved toward the fused sperm. Sperm extracts lacking nuclei induced Ca2+ oscillations, but did not promote mitochondrial chemotaxis. Our results suggest that sperm fusion motivates Ca2+ oscillation-independent mitochondrial chemotaxis. This phenomenon indicates that egg mitochondria interact with sperm materials, presumably nuclear substances, and their network tethers egg and sperm nuclei at the early stage of zygote formation.

© 2018 Molecular Biology Society of Japan and John Wiley & Sons Australia, Ltd In bacteria, a polymer of inorganic phosphate (Pi) (inorganic polyphosphate; polyP) is enzymatically produced and consumed as an alternative phosphate donor for adenosine triphosphate (ATP) production to protect against nutrient starvation. In vertebrates, polyP has been dismissed as a “molecular fossil” due to the lack of any known physiological function. Here, we have explored its possible role by producing transgenic (TG) mice widely expressing Saccharomyces cerevisiae exopolyphosphatase 1 (ScPPX1), which catalyzes hydrolytic polyP degradation. TG mice were produced and displayed reduced mitochondrial respiration in muscles. In female TG mice, the blood concentration of lactic acid was enhanced, whereas ATP storage in liver and brain tissues was reduced significantly. Thus, we suggested that the elongation of polyP reduces the intracellular Pi concentration, suppresses anaerobic lactic acid production, and sustains mitochondrial respiration. Our results provide an insight into the physiological role of polyP in mammals, particularly in females.

© 2018 The Authors Autophagic recycling of cell parts is generally termed as the opposite of cell death. Here, we explored the relation between cell death and autophagy by examining granulosa cell layers that control oocyte quality, which is important for the success of fertilization. Granulosa cell layers were collected from infertile women and morphologically divided into four types, viz., mature (MCCs), immature (ICCs), and dysmature cumulus cells (DCCs), and mural granulosa cells (MGCs). Microtubule-associated protein light chain 3 (LC3), which is involved in autophagosome formation, was expressed excessively in DCCs and MGCs, and their chromosomal DNA was highly fragmented. However, autophagy initiation was limited to MGCs, as indicated by the expression of membrane-bound LC3-II and autophagy-related protein 7 (ATG7), an enzyme that converts LC3-I to LC3-II. Although pro-LC3 was accumulated, autophagy was disabled in DCCs, resulting in cell death. Our results suggest the possibility that autophagy-independent accumulation of pro-LC3 proteins leads to the death of human granulosa cells surrounding the oocytes and presumably reduces oocyte quality and female fertility.

The ubiquitin-proteasome system, which is initiated by a single ubiquitin-activating enzyme E1 (UBE1), is involved in male reproduction via spermatogenesis and function in mammals. Here we explored the influence of UBE1-specific inhibitor, 4[4-(5-nitro-furan-2-ylmethylene)-3,5-dioxo-pyrazolidin-1-yl]-benzoic acid ethyl ester (pyrazone-41 or PYR-41) in female reproduction. UBE-1 was detected by immunoblotting and immunocytochemistry in mouse eggs and was localized mainly under the egg plasma membrane. PYR-41 pretreatment suppresses the development of eggs into two-cell embryos. Specifically, pretreatment retarded sperm enlargement and meiotic chromosomal division after sperm-egg fusion. PYR-41 pretreatment disturbed β-catenin, a well-known target protein for ubiquitination, localization under the egg plasma membrane and on spindle microtubules in wild-type eggs. Otherwise, PYR-41 treatment had no effect on the two-cell development of eggs lacking β-catenin. Our results raise the possibility that inhibition of the ubiquitin-proteasome system suppresses sperm enlargement through impaired β-catenin-mediated mechanism.

To evaluate the clinical efficacy of a procedure comprising a combination of Percoll continuous density gradient and modified swim-up techniques for the removal of human immunodeficiency virus type 1 (HIV-1) from the semen of HIV-1 infected males, a total of 129 couples with an HIV-1 positive male partner and an HIV-1 negative female partner (serodiscordant couples) who were treated at Keio University Hospital between January 2002 and April 2012 were examined. A total of 183 ejaculates from 129 HIV-1 infected males were processed. After swim-up, we successfully collected motile sperms at a recovery rate as high as 100.0% in cases of normozoospermia (126/126 ejaculates), oligozoospermia (6/6), and asthenozoospermia (36/36). The recovery rate of oligoasthenozoospermia was 86.7% (13/15). In processed semen only four ejaculates (4/181:2.2%) showed viral nucleotide sequences consistent with those in the blood of the infected males. After using these sperms, no horizontal infections of the female patients and no vertical infections of the newborns were observed. Furthermore, no obvious adverse effects were observed in the offspring. This protocol allowed us to collect HIV-1 negative motile sperms at a high rate, even in male factor cases. We concluded that our protocol is clinically effective both for decreasing HIV-1 infections and for yielding a healthy child.

To investigate pregnancy outcomes in women after abdominal radical trachelectomy (RT) for early-stage cervical cancer.|The patients' background, fertility, and pregnancy outcomes were reviewed in a total of 61 pregnancies in 48 of 172 women who underwent abdominal RT at Keio University Hospital between September 2002 and December 2013.|There were 5 women with stage IA1, 2 with stage IA2, and 41 with stage IB1. Histological types were as follows: squamous cell carcinoma (n = 36), adenocarcinoma (n = 10), and adenosquamous cell carcinoma (n = 2). The pregnancy rate of women attempting to conceive after abdominal RT was 44% (48/109). The mean ± SD duration from abdominal RT to conception was 3.1 ± 1.9 years. Of 61 pregnancies, 42 pregnancies were achieved by fertility treatment (in vitro fertilization-embryo transfer, 39; intrauterine insemination, 3). After excluding one pregnancy without detailed clinical information, there were 42 live births (5 in 22-27 weeks, 11 in 28-33weeks, 20 in 34-36 weeks, and 6 in 37-38 weeks), 13 miscarriages, and 5 ongoing pregnancies. While there were 10 first trimester miscarriages, 3 pregnancies ended in the second trimester owing to chorioamnioniti

Background: Patients hoping to preserve their fertility receive conservative treatment with high-dose medroxyprogesterone acetate (MPA) for well-differentiated endometrioid adenocarcinoma (EC) or atypical endometrial hyperplasia (AEH). Such treatment generally involves frequent intrauterine operations, including dilation and curettage (D&C) and endometrial biopsy (EMB), which could result in endometritis, endometrial thinning, or intrauterine adhesion. In turn, any of these outcomes could adversely affect implantation and pregnancy development. The current study thus aimed to identify factors that might affect pregnancy following conservative treatment by MPA. Methods: We compared a pregnancy group (45 patients) with a non-pregnancy group (53 patients) of MPA-treated patients to evaluate the factors affecting clinical pregnancy establishment. We undertook a multivariate logistic regression analysis based on factors shown by univariate analysis to be significantly different between the groups. Univariate analysis identified number of D&C, endometrial thickness, duration of MPA administration, age of pregnancy permission (the age at which a patient was first allowed to attempt pregnancy after disappearance of the lesion), period of disappearance of lesions, and recurrence as independent variables. Results: The odds ratios (95 % confidence interval) of multivariate analysis for disease recurrence, endometrial thickness during ovulation, and age of pregnancy permission were 0.283 (0.102-0.785), 1.677 (1.251-2.248), and 0.889 (0.792-0.998), respectively. There was no significant difference in the other independent variables between groups. Conclusions: We identified three factors considered to affect pregnancy establishment following conservative treatment with MPA: recurrence, endometrial thickness during ovulation, and the age of the pregnancy permission. Introduction of infertility treatment including assisted reproductive technology (ART) soon after achieving tumor disappearance by MPA would therefore be beneficial for patients with disease recurrence, thin endometrium, or a higher age of pregnancy permission.

The present review aims to ascertain whether different infertility etiologies share particular genes and/or molecular pathways with other pathologies and are associated with distinct and particular risks of later-life morbidity and mortality. In order to reach this aim, we use two different sources of information: (1) a public web server named DiseaseConnect (http://disease-connect.org) focused on the analysis of common genes and molecular mechanisms shared by diseases by integrating comprehensive omics and literature data; and (2) a literature search directed to find clinical comorbid relationships of infertility etiologies with only those diseases appearing after infertility is manifested. This literature search is performed because DiseaseConnect web server does not discriminate between pathologies emerging before, concomitantly or after infertility is manifested. Data show that different infertility etiologies not only share particular genes and/or molecular pathways with other pathologies but they have distinct clinical relationships with other diseases appearing after infertility is manifested. In particular, (1) testicular and high-grade prostate cancer in male infertility; (2) non-fatal stroke and endometrial cancer, and likely non-fatal coronary heart disease and ovarian cancer in polycystic ovary syndrome; (3) osteoporosis, psychosexual dysfunction, mood disorders and dementia in premature ovarian failure; (4) breast and ovarian cancer in carriers of BRCA1/2 mutations in diminished ovarian reserve; (5) clear cell and endometrioid histologic subtypes of invasive ovarian cancer, and likely low-grade serous invasive ovarian cancer, melanoma and non-Hodgkin lymphoma in endometriosis; and (6) endometrial and ovarian cancer in idiopathic infertility. The present data endorse the principle that the occurrence of a disease (in our case infertility) is non-random in the population and suggest that different infertility etiologies are genetically and clinically linked with other diseases in single meta-diseases. This finding opens new insights for clinicians and reproductive biologists to treat infertility problems using a phenomic approach instead of considering infertility as an isolated and exclusive disease of the reproductive system/hypothalamic-pituitary-gonadal axis. In agreement with a previous validation analysis of the utility of DiseaseConnect web server, the present study does not show a univocal correspondence between common gene expression and clinical comorbid relationship. Further work is needed to untangle the potential genetic, epigenetic and phenotypic relationships that may be present among different infertility etiologies, morbid conditions and physical/cognitive traits.

Recently, infertility treatment-related psychological effects are receiving increased attention. However, whether sexual satisfaction is reduced amongst infertile couples remains to be elucidated. In this study, sexual satisfaction of Japanese infertile couples was assessed using a validated questionnaire designed to assess the male and female partner individually, and the couple as a whole for the first time. This study randomly included 170 infertile couples seen at the outpatient clinic and 170 couples that had recently achieved spontaneous pregnancy. All couples were given the Japanese version of the Golombok-Rust Inventory of Sexual Satisfaction (GRISS). In couples aged 35 years or older, the male partners showed significantly worse sexual satisfaction scores than the female partners. Sexual satisfaction also deteriorated with therapeutic interventions, with mental factors affected more than physical factors. Therapeutic interventions such as timed sexual intercourse and assisted reproductive technology were considered emotionally stressful for infertile couples, with sexual satisfaction accordingly lower in this group than in couples achieving spontaneous pregnancy. GRISS successfully evaluated lower sexual satisfaction associated with infertility, and hence is a useful tool for identifying couples whose sexual satisfaction could be enhanced by counselling or other stress-reduction modalities.

We induced differentiation of human amnion-derived mesenchymal stem cells (AMCs) and menstrual blood-derived mesenchymal stem cells (MMCs) into endometrial stroma-like cells, which could be useful for cell therapy to support embryo implantation. Interestingly, the expression patterns of surface markers were similar among AMCs, MMCs, and endometrial stromal cells. In addition, whereas treatment with estrogen and progesterone was not very effective for decidualizing AMCs and MMCs, treatment with 8-Br-cAMP prompted remarkable morphological changes in these cells as well as increased expression of decidualization markers (prolactin and insulin-like growth factor binding protein-1) and attenuated expression of surface markers unique to mesenchymal stem cells. These results demonstrated that bone marrow-derived stem cells, which are considered a potential source of endometrial progenitor cells, as well as AMCs and MMCs show in vitro decidualization potential, which is characteristic of endometrial stromal cells.