The onset of pregnancy is marked by the formation of a zygote, while the culmination of gestation is manifested by the delivery of a fetus. Meanwhile, a successful pregnancy entails a meticulously coordinated sequence of events from embryo implantation to sustained decidualization of the uterus to placental development and childbirth. The decidual reaction, a pivotal process occurring within the endometrium during pregnancy, is finely regulated by sex steroids and cytokines. Notably, fibroblast growth factors (FGFs), particularly FGF2, play a critical role in this physiological cascade. Dysregulated FGF expression may trigger inadequate decidualization, precipitating a spectrum of adverse pregnancy outcomes, including preeclampsia, recurrent implantation failure, and miscarriage. Furthermore, the human decidua, distinct from most mammalian species and similar to great apes, undergoes regular cycles of formation and shedding, independent of the presence of the embryo in the endometrium. This process is also tightly controlled by various FGFs. In this review, we comprehensively compare diverse research decidualization models, delineate the trend of endometrial FGFs during the menstrual cycle, and provide a synopsis of endometrial diseases triggered by FGF dysregulation.
Humans ; Female ; Pregnancy ; Decidua/physiology* ; Animals ; Endometrium/physiology* ; Fibroblast Growth Factors/metabolism* ; Embryo Implantation ; Menstrual Cycle/physiology*

Embryo implantation involves a complex interaction between the embryo and the endometrium of the mother, the study of which faces a variety of problems. The modeling of endometrial epithelial organoids and endometrial assembloids provides a new way to study the process of embryo implantation in vitro. This paper summarized the latest research progress in embryo implantation, the regulation mechanism of endometrial receptivity by estrogen- progesterone coordination and embryo-derived signals, the establishment of endometrial organoids, and the development and application of endometrial assembloids in the research on mother-embryo interaction, providing new strategies for studying the communication between embryo and maternal uterus during implantation.
Endometrium/physiology* ; Organoids/cytology* ; Embryo Implantation/physiology* ; Female ; Animals ; Progesterone/pharmacology* ; Pregnancy ; Estrogens/metabolism* ; Humans

Endometrial receptivity has become the main cause of fertilization and pregnancy outcomes in infertile patients,bringing large psychological damage and economic loss to the patients and their family. In recent years,the role of non-coding RNA has increasingly been recognized. The relationship between non-coding RNA and endometrial receptivity is reviewed in this article.
Embryo Implantation ; Endometrium ; physiology ; Female ; Fertilization in Vitro ; Humans ; Pregnancy ; Pregnancy Outcome ; RNA, Untranslated ; genetics

Angiotensin-converting enzyme functions in the male reproductive system, but the extent of its function in reproduction is not fully understood. The primary objective of this work was to investigate the relationship between the testicular isoform of angiotensin-converting enzyme present in human spermatozoa and semen parameters, human embryo quality, and assisted reproduction success. A total of 81 semen samples and 635 embryos from couples undergoing oocyte donation cycles at the IVI Bilbao Clinic were analyzed. Semen parameters, embryos quality, and blastocyst development were examined according to the World Health Organization standards and the Spanish Association of Reproduction Biology Studies criteria. The percentage of testicular angiotensin-converting enzyme-positive spermatozoa and the number of molecules per spermatozoon were analyzed by flow cytometry. Both parameters were inversely correlated with human sperm motility. Higher percentages of testicular angiotensin-converting enzyme-positive spermatozoa together with fewer enzyme molecules per spermatozoon were positively correlated with better embryo quality and development. Our results suggest that embryos with a higher implantation potential come from semen samples with higher percentages of testicular angiotensin-converting enzyme-positive cells and fewer enzyme molecules per spermatozoon. Based on these findings, we propose that testicular angiotensin-converting enzyme could be used to aid embryologists in selecting better semen samples for obtaining high-quality blastocysts during in vitro fertilization procedures.
Adult ; Embryo Implantation/physiology* ; Embryo Transfer ; Embryonic Development/physiology* ; Fertility/physiology* ; Fertilization in Vitro ; Humans ; Male ; Middle Aged ; Peptidyl-Dipeptidase A/metabolism* ; Sperm Motility/physiology* ; Spermatozoa/enzymology* ; Testis/enzymology*

BACKGROUNDAt present, a diagnostic tool with high specificity for impaired endometrial receptivity, which may lead to implantation failure, remains to be developed. We aimed to assess the different endometrial microRNA (miRNA) signatures for impaired endometrial receptivity by microarray analysis.

METHODSA total of 12 repeated implantation failure (RIF) patients and 10 infertile patients, who conceived and delivered after one embryo transfer attempt, were recruited as RIF and control groups, respectively. Endometrial specimens from the window of implantation (WOI) were collected from these two groups. MiRNA microarray was conducted on seven and five samples from the RIF and control groups, respectively. Comparative, functional, and network analyses were performed for the microarray results. Quantitative real-time polymerase chain reaction (PCR) was performed on other samples to validate the expression of specific miRNAs.

RESULTSCompared with those in the control group, the expression levels of 105 miRNAs in the RIF group were found to be significantly up- or down-regulated (at least 2-fold) by microarray analysis. The most relevant miRNA functional sets of these dysregulated miRNAs were miR-30 family, human embryonic stem cell regulation, epithelial-mesenchymal transition, and miRNA tumor suppressors by tool for annotations of microRNA analysis. Network regulatory analysis found 176 miRNA-mRNA interactions, and the top 3 core miRNAs were has-miR-4668-5p, has-miR-429, and has-miR-5088. Expression levels of the 18 selected miRNAs in new samples by real-time PCR were found to be regulated with the same trend, as the result of microarray analysis.

CONCLUSIONSThere is a significant different expression of certain miRNAs in the WOI endometrium for RIF patients. These miRNAs may contribute to impaired endometrial receptivity.

Adult ; Embryo Implantation ; genetics ; physiology ; Endometrium ; metabolism ; Female ; Humans ; Infertility, Female ; genetics ; MicroRNAs ; genetics ; Microarray Analysis ; Pregnancy ; Real-Time Polymerase Chain Reaction

OBJECTIVETo investigate the influence of the rate of morphologically normal sperm (MNS) on the clinical outcomes of conventional in vitro fertilization (IVF) in patients with one retrieved oocyte.

METHODSFrom January 2013 to January 2015, a total of 256 couples with one retrieved oocyte underwent conventional IVF in our center. According to the rate of MNS, the patients were divided into two groups: MNS < 4% (134 cycles) and MNS ≥ 4% (122 cycles). We compared the rates of no transferrable embryo cycles, fertilization, cleavage, normal fertilization, abnormal fertilization, high-quality embryo and transferrable embryo between the two groups. A total of 75 fresh embryo transfer cycles were performed, 43 in the MNS < 4% group and the other 32 in the MNS ≥ 4% group. We also compared the rates of implantation, clinical pregnancy and abortion between the two groups.

RESULTSThere were no statistically significant differences between the two groups in the rates of no transferrable embryo cycles, fertilization, cleavage, normal fertilization, abnormal fertilization, high-quality embryo and transferrable embryo (P > 0.05). The rates of implantation, clinical pregnancy and abortion exhibited no remarkable differences either in the fresh embryo transfer cycles between the two groups (P > 0.05).

CONCLUSIONThe rate of MNS does not affect the clinical outcomes of conventional IVF in patients with one retrieved oocyte.

Abortion, Spontaneous ; Cleavage Stage, Ovum ; Embryo Implantation ; Female ; Fertilization ; Fertilization in Vitro ; methods ; statistics & numerical data ; Humans ; Male ; Oocyte Retrieval ; Pregnancy ; Pregnancy Rate ; Single Embryo Transfer ; statistics & numerical data ; Sperm Count ; Spermatozoa ; physiology

This study investigated the molecular markers of DS-1-47, a component of an implantation- promoting traditional Chinese medicine consisting of Astragalus mongholicus, Atractylodes macrocephala, Scutellaria baicalensis and Dipsacales, in an attempt to clarify the molecular mechanism and action targets of DS-1-47. Controlled ovarian stimulation (COS) method was used to establish the implantation dysfunction models of mice. Animals were divided into normal pregnant group, COS model group and DS-1-47 group. Laser capture microdissection-double dimensional electrophoresis-mass spectrum (LCM-DE-MS) was used to analyze the uterine protein molecules that were possibly involved in the promotion of implantation. Twenty-three proteins in DS-1-47 group were significantly changed as compared to those in COS model group, with 7 proteins down-regulated and 16 proteins up-regulated. Except for some constituent proteins, the down-regulated proteins included collagen α-1 (VI) chain, keratin 7, keratin 14, myosin regulatory light chain 12B, myosin light polypeptide 9, heat shock protein β-7, and C-U-editing enzyme APOBEC-2; the up-regulated proteins included apolipoprotein A-I, calcium regulated protein-3, proliferating cell nuclear antigen, L-xylulose reductase, and calcium binding protein. These 23 proteins that were regulated by DS-1-47 represented a broad diversity of molecule functions. The down-regulated proteins were associated with stress and immune response, and those up-regulated proteins were related to proliferation. It was suggested that these proteins were important in regulating the uterine environment for the blastocyst implantation. By identification of DS-1-47 markers, proteomic analysis coupled with functional assays is demonstrated to be a promising approach to better understand the molecular mechanism of traditional Chinese medicine.
Animals ; Drugs, Chinese Herbal ; pharmacology ; Embryo Implantation ; drug effects ; Female ; Mice ; Ovulation Induction ; Pregnancy ; Proteome ; genetics ; metabolism ; Uterus ; drug effects ; metabolism ; physiology

OBJECTIVETo investigate the role of endometrial macrophages in embryo implantation and in regulating the expression of vascular endothelial growth factor A (VEGFA) in mouse endometrium during the peri-implantation period.

METHODAt D3.5 (D0.5 defined as the morning when a vaginal plug was observed), pregnant mice were divided randomly into experimental group, control group and blank group. In the experimental group, the mice were subjected to intrauterine injection of clodronate liposomes on the left side of uterus to eliminate the macrophages, and PBS liposomes on the right side. PBS liposomes and PBS were administered in the control and blank groups, respectively. The uterine tissues were collected on D5.5 and stained with trypan blue to show the implantation sites. Flow cytometry was performed to examine the percentage of F4/80(+) CD11b(+) macrophages macrophages in the uterus. F4/80(+) macrophage population within the endometrium and ovary and changes in VEGFA expression at the implantation and non-implantation sites were examined using immunohistochemistry.

RESULTSEndometrial F4/80(+) CD11b(+) macrophages macrophages were significantly reduced by 74% following intrauterine injection of clodronate liposomes (P<0.05). The number of macrophages in the ovaries showed no significant difference among the 3 groups. In the experimental group, the left side of the uterine showed imcomplete cavity closure with a lower number of implantation site than the right side (2.20∓1.81 vs 5.10∓1.91, P<0.05). VEGFA expression at the implantation site were significantly decreased in the endometrium on the left side with macrophage suppression as compared with that on the right side (P<0.05).

CONCLUSIONEndometrial macrophages appear to modulate uterine receptivity by regulating the expression of VEGFA to affect embryo implantation, suggesting the important role of macrophages in embryo implantation.

Animals ; Embryo Implantation ; Endometrium ; physiology ; Female ; Immunohistochemistry ; Macrophages ; cytology ; Mice ; Ovary ; cytology ; Pregnancy ; Random Allocation ; Uterus ; cytology ; Vascular Endothelial Growth Factor A ; physiology

OBJECTIVETo evaluate the impact of sperm midpiece morphology observed under high-power microscope on embryo development following intracytoplasmic morphologically selected sperm injection.

METHODSMorphologically normal sperms from 57 patients undergoing intracytoplasmic sperm injection (ICSI) for male-factor infertility were selected microscopically (magnification of ×200 or 400) and subjected to motile sperm organellar morphology examination (MSOME) at high magnification of ×6000. According to the morphology of sperm medpiece, the sperms were divided into 3 groups, namely group A with a/b of 1-1.2, group B with a/b≥1.5, and group C with irregular morphology. The sperms in the 3 groups were intracytoplasmically injected in oocytes and the outcomes of the embryos were compared.

RESULTSGroups A, B, and C showed significant differences in the rate of ET-D3 top quality embryo (79.7% vs 55.6 % vs 33.3%) and implantation rate (43.2% vs 11.1% vs 0%), but not in the fertilization rate (73.3% vs 80.4% vs 63.5%), blastocyst formation rate (23.2% vs 22.2% vs 9.09%), cryopreservation rate (29.2% vs 25.0 % vs 13.0%), or D3 top quality embryo rate (35.3% vs 37.8% vs 18.8%).

CONCLUSIONSIn ICSI cycle, selecting morphologically normal sperms for intracytoplasic injection can increase the normal fertilization rate and top quality embryo rate on the transfer day and improve the implantation rate of the embryo.

Cryopreservation ; Embryo Implantation ; Embryonic Development ; Female ; Fertilization ; Humans ; Infertility, Male ; Male ; Oocytes ; Semen Analysis ; Sperm Injections, Intracytoplasmic ; Sperm Midpiece ; physiology

The aim of this study was to investigate the effect of Bu-Shen-An-Tai recipe (BSATR) and its two components (Bushen recipe, and Huoxue recipe) on endometrial morphology during peri-implantation in superovulated mice. Mice were randomly divided into five groups, including the normal (N), model (M), Bushen (BS), Huoxue (HX) and Bu-Shen-An-Tai (BH) groups. The uteri were collected on day 4 of pregnancy, and the endometrium thickness, microvessel density (MVD) and number of pinopodes observed. Compared with the M group, the endometrial thickness in the BS, HX and BH groups was significantly increased and there was a significant difference in endometrial thickness between the BS and the BH groups. The mean MVD was significantly lower in the M group than in the N group, and there was a significant increase in MVD in the BS, HX and BH groups as compared with the M group. Compared with the M group, the pinopode scores in the endometrium were significantly increased in the HX and BH groups; and the BS group had significantly higher pinipode scores than the HX and BH groups. In conclusion, the results of the present study demonstrated that the recipes (Bushen, Huoxue and BSATR) could improve the endometrial environment by regulating the endometrial thickness, MVD and the number of pinopodes at the window of implantation. Moreover, the Huoxue recipe and the BSATR were more efficient than the Bushen recipe, with the BSATR tending to have the most beneficial effects.
Animals ; Antigens, CD34 ; metabolism ; Drugs, Chinese Herbal ; chemistry ; pharmacology ; Embryo Implantation ; physiology ; Endometrium ; drug effects ; physiology ; ultrastructure ; Female ; Immunohistochemistry ; Mice ; Microscopy, Electron, Scanning ; Microvessels ; metabolism ; physiology ; Ovulation ; physiology ; Pregnancy ; Random Allocation ; Time Factors