Human Endometrium-Derived Adventitial Cell Spheroid-Loaded Antimicrobial Microneedles for Uterine Regeneration.

Asherman's syndrome (AS) occurs as a consequence of severe damage to the endometrial basalis, usually leading to menstrual abnormalities, infertility, and recurrent miscarriage in women. Currently, human endometrium-derived adventitial cells (En-ADVs) are considered ideal seed cells with high pluripotency for regenerative medicine. However, critical issues such as noninvasive repair of tissues, targeting of native stem cells, and continuous action in the injured sites are not well resolved. Herein, En-ADV spheroid-loaded hierarchical microneedles (MN/En-ADV) for in situ intrauterine repair are developed. The flexible microneedles are fabricated with gelatin methacryloyl and lactoferrin, imparting the characteristics of rapid degradation and antimicrobial activity. Benefiting from an array of microwells on microneedles, En-ADVs can rapidly form 3D cell spheroids, which display higher potential for cell proliferation, differentiation, and migration than dissociated cells. With the application of MN/En-ADV, the repaired uteri show well-defined myometrial regeneration, angiogenesis, and an increase of endometrial receptivity in a rat AS model. Notably, embryos are able to implant in the reconstructed sites and remain viable, indicating that this system promotes the restoration of both normal morphology and reproductive function in the injured uterus. It is anticipated that multifunctional MN/En-ADV can be an ideal candidate for versatile in situ tissue regeneration.

Glycomics reveal that ST6GAL1-mediated sialylation regulates uterine lumen closure during implantation.

OBJECTIVES: Implantation failure is a major cause of prenatal mortality. The uterine lumen closure contributes to embryo adhesion to the uterus, but its underlying mechanisms are largely unknown. Our previous study has reported that endometrial fold extension can lead to uterine lumen closure in pigs. The objective of this study was to reveal molecular mechanisms of the uterine lumen closure by characterizing the molecular basis of the endometrial fold extension during implantation in pigs. MATERIALS AND METHODS: Uterine and endometrium tissues during implantation were collected in pigs. MALDI-TOF MS was used to characterize the N-glycomic profiles. Histochemistry, siRNA transfection, Western blotting, lectin immumoprecipitation, mass spectrometry and assays of wounding healing and cell aggregation were performed to investigate the molecular basis. RESULTS: We observed that uterine luminal epithelium (LE) migrated collectively during endometrial fold extension. For the first time, we identified a large number of N-glycan compositions from endometrium during implantation using MALDI-TOF MS. Notably, the α2,6-linked sialic acid and ST6GAL1 were highly expressed in uterine LE when the endometrial folds extended greatly. Subsequently, the role of ST6GAL1-mediated 2,6-sialylation in collective epithelial migration was demonstrated. Finally, we found that ST6GAL1-mediated α2,6-sialylation of E-cadherin may participate in collective migration of uterine LE. CONCLUSIONS: The study reveals a mechanism of uterine lumen closure by identifying that ST6GAL1-mediated α2,6-sialylation of cell adhesion molecules contributes to endometrial fold extension through regulating collective migration of uterine LE.

Analysis of Healing of Rat Uterine Wall After Full-Thickness Surgical Incision.

We studied the dynamics of morphological changes in the operated segment of the uterine horn of Sprague-Dawley rats during the first 2 weeks of the wound-healing process after a full-thickness surgical incision with regard to the estrous cycle phase. Morphometric parameters of injured uterine right horn were compared with those in the intact left horn of the same animal as a control of changes determined by the hormonal background. It was found that the uterine epithelium in the focus of injury was restored as soon as on day 2 after surgery under the influence of estrous cycle hormones. By day 4, the wound space was completely filled with the endometrial tissue on the side of the uterine lumen and coved by the attached adipose tissue of the mesentery on the side of the abdominal cavity. The thickness of the uterine wall and the uterine lumen differed most strongly between the operated and intact uterine horns during the first 3 days and on day 6 after surgery. The size of the healing area increased during the first three days and reached the peak value by day 3, but then decreased to minimum by day 6.

AG-205 Upregulates Enzymes Involved in Cholesterol Biosynthesis and Steroidogenesis in Human Endometrial Cells Independently of PGRMC1 and Related MAPR Proteins.

An inappropriate response to progestogens in the human endometrium can result in fertility issues and jeopardize progestin-based treatments against pathologies such as endometriosis. PGRMC1 can mediate progesterone response in the breast and ovaries but its endometrial functions remain unknown. AG-205 is an alleged PGRMC1 inhibitor but its specificity was recently questioned. We added AG-205 in the cultures of two endometrial cell lines and performed a transcriptomic comparison. AG-205 significantly increased expression of genes coding enzymes of the cholesterol biosynthetic pathway or of steroidogenesis. However, these observations were not reproduced with cells transfected with siRNA against PGRMC1 or its related proteins (MAPRs). Furthermore, AG-205 retained its ability to increase expression of selected target genes even when expression of PGRMC1 or all MAPRs was concomitantly downregulated, indicating that neither PGRMC1 nor any MAPR is required to mediate AG-205 effect. In conclusion, although AG-205 has attractive effects encouraging its use to develop therapeutic strategies, for instance against breast cancer, our study delivers two important warning messages. First, AG-205 is not specific for PGRMC1 or other MAPRs and its mechanisms of action remain unclear. Second, due to its effects on genes involved in steroidogenesis, its use may increase the risk for endometrial pathologies resulting from imbalanced hormones concentrations.

Outcomes of Deferoxamine Action on H2O2-Induced Growth Inhibition and Senescence Progression of Human Endometrial Stem Cells.

Mesenchymal stem cells (MSCs) are broadly applied in regenerative therapy to replace cells that are lost or impaired during disease. The low survival rate of MSCs after transplantation is one of the major limitations heavily influencing the success of the therapy. Unfavorable microenvironments with inflammation and oxidative stress in the damaged regions contribute to MSCs loss. Most of the strategies developed to overcome this obstacle are aimed to prevent stress-induced apoptosis, with little attention paid to senescence-another common stress reaction of MSCs. Here, we proposed the strategy to prevent oxidative stress-induced senescence of human endometrial stem cells (hMESCs) based on deferoxamine (DFO) application. DFO prevented DNA damage and stress-induced senescence of hMESCs, as evidenced by reduced levels of reactive oxygen species, lipofuscin, cyclin D1, decreased SA-ß-Gal activity, and improved mitochondrial function. Additionally, DFO caused accumulation of HIF-1α, which may contribute to the survival of H2O2-treated cells. Importantly, cells that escaped senescence due to DFO preconditioning preserved all the properties of the initial hMESCs. Therefore, once protecting cells from oxidative damage, DFO did not alter further hMESCs functioning. The data obtained may become the important prerequisite for development of a new strategy in regenerative therapy based on MSCs preconditioning using DFO.

Combination of Ferulic Acid, Ligustrazine and Tetrahydropalmatine attenuates Epithelial-mesenchymal Transformation via Wnt/ß-catenin Pathway in Endometriosis.

Previously the potential therapeutic action of ferulic acid, ligustrazine and tetrahydropalmatine (FLT) are discovered with unclear mechanism in rat autograft endometriosis. However, the effect of FLT on endometrial cells and allograft endometriosis is still unclear. This study is designed to elucidate the influence of FLT on epithelial-mesenchymal transformation in allograft endometriosis and endometrium cells. In vivo, fluorescent xenogeneic endometriosis model was established. In vitro, invasion and metastasis were analyzed after treating FLT. Epithelial-mesenchymal transformation and Wnt/ß-catenin pathway were inspected in vitro and in vivo. Activator or inhibitor of Wnt/ß-catenin signaling was performed to inspect mechanism of epithelial-mesenchymal transformation. In vivo, FLT not only decreased fluorescent intensity and volume of ectopic lesion, but also ameliorated pathological morphology. E2 and PROG levels in serum were reduced by FLT. In endometrial cells, FLT significantly inhibited the invasion and metastasis. Meantime, epithelial-mesenchymal transformation was reversed, accompanied by suppression of Wnt/ß-catenin pathway. In-depth study, activation of Wnt/ß-catenin pathway lead to promotion of epithelial-mesenchymal transformation, which was reversed by FLT. FLT prevented fluorescent allograft endometriosis and endometrium cells, which was related to suppress epithelial-mesenchymal transformation through inactivating Wnt/ß-catenin pathway. The findings disclose molecular mechanism of epithelial-mesenchymal transformation in endometriosis by FLT, and contribute to further application.

Menstrual flow as a non-invasive source of endometrial organoids.

Assessment of the endometrium often necessitates a biopsy, which currently involves an invasive, transcervical procedure. Here, we present an alternative technique based on deriving organoids from menstrual flow. We demonstrate that organoids can be derived from gland fragments recovered from menstrual flow. To confirm they faithfully reflect the in vivo state we compared organoids derived from paired scratch biopsies and ensuing menstrual flow from patients undergoing in vitro fertilisation (IVF). We demonstrate that the two sets of organoids share the same transcriptome signature, derivation efficiency and proliferation rate. Furthermore, they respond similarly to sex steroids and early-pregnancy hormones, with changes in morphology, receptor expression, and production of 'uterine milk' proteins that mimic those during the late-secretory phase and early pregnancy. This technique has wide-ranging impact for non-invasive investigation and personalised approaches to treatment of common gynaecological conditions, such as endometriosis, and reproductive disorders, including failed implantation after IVF and recurrent miscarriage.

Frozen-thawed embryo transfers: time to adopt a more "natural" approach?

The increasing use of frozen-thawed embryo transfer (FET) cycles has magnified the focus on endometrial preparation protocols in assisted reproduction. Emerging evidence suggests that natural cycle (NC) FETs are associated with improved outcomes, and that providers should consider increasing the utilization of NC FET at the expense of the currently favored artificial cycle (AC) FET as primary method for endometrial preparation.

Endometrial extracellular vesicles of recurrent implantation failure patients inhibit the proliferation, migration, and invasion of HTR8/SVneo cells.

PURPOSE: Endometrial extracellular vesicles are essential in regulating trophoblasts' function. This study aims to investigate whether endometrial extracellular vesicles (EVs) from recurrent implantation failure (RIF) patients inhibit the proliferation, invasion, and migration of HTR8/SVneo cells. METHODS: Eighteen RIF patients and thirteen fertile women were recruited for endometria collection. Endometrial cells isolated from the endometria were cultured and modulated by hormones, and the conditioned medium was used for EV isolation. EVs secreted by the endometrial cells of RIF patients (RIF-EVs) or fertile women (FER-EVs) were determined by Western blotting, nanoparticle tracking analysis, and transmission electron microscopy. Fluorescence-labeled EVs were used to visualize internalization by HTR8/SVneo cells. RIF-EVs and FER-EVs were co-cultured with HTR8/SVneo cells. Cell Counting Kit-8, transwell invasion, and wound closure assays were performed to determine cellular proliferation, invasion, and migration, respectively, in different treatments. RESULTS: RIF-EVs and FER-EVs were bilayer membrane vesicles, ranging from 100 to 150 nm in size, that expressed the classic EV markers Alix and CD9. RIF-EVs and FER-EVs were internalized by HTR8/SVneo cells within 2 h. The proliferation rate in the FER-EV group was significantly higher than that in the RIF-EV group at 20 µg/mL. Moreover, the invasion and migration capacity of trophoblast cells were decreased in the RIF-EV group relative to the FER-EV group at 20 µg/mL. CONCLUSION: Endometrial EVs from RIF patients inhibited the functions of trophoblasts by decreasing their proliferation, migration, and invasive capacity. Such dysregulations induced by RIF-EVs may provide novel insights for better understanding the pathogenesis of implantation failure.

Isolation, Culture, and Characterization of Primary Bovine Endometrial, Epithelial, and Stromal Cells for 3D In Vitro Tissue Models.

Efficient isolation, characterization, and culture of endometrial epithelial cells and stromal fibroblasts from calf uteri collected at the slaughterhouse is key to develop useful 3D culture tissue models to investigate uterine physiology and pathology without the need of performing invasive procedures to recover tissue samples.Here we provide a detail methodology that gives consistently pure and viable populations of distinct primary bovine endometrial cells.

Endometrial compaction does not predict live birth rate in single euploid frozen embryo transfer cycles.

PURPOSE: To evaluate whether endometrial compaction using sequential transvaginal ultrasound is associated with improved live birth rates in medicated single euploid frozen embryo transfer (FET) cycles. METHODS: Prospective observational cohort study at a private fertility clinic. Patients who underwent FETs between January and December 2018 were assessed for inclusion. The change in endometrial thickness between the end of the estrogen phase and the day before embryo transfer, measured by sequential transvaginal ultrasound, was used to categorize cycles with compaction (≥ 5%), no change, or expansion (≥ 5%). FET cycle outcomes were then compared between groups. The primary outcome was live birth. Secondary outcomes include clinical pregnancy rate and rate of spontaneous abortion. RESULTS: Of the 259 single euploid medicated FETs performed during the study period, only 43/259 (16.6%) of the cycles demonstrated ≥ 5% compaction, whereas 152/259 (58.7%) expanded and 64/259 (24.7%) were unchanged. Live birth rates did not differ between cycles with compaction (58.1%), no change (54.7%), or expansion (58.6%), p = 0.96. Clinical pregnancy and spontaneous abortion rates were also similar between groups. CONCLUSION: The vast majority of cycles did not demonstrate endometrial compaction. Endometrial compaction is not associated with live birth rate or spontaneous abortion rate in medicated single euploid FETs in this cohort.

Integrating LCM-Based Spatio-Temporal Transcriptomics Uncovers Conceptus and Endometrial Luminal Epithelium Communication that Coordinates the Conceptus Attachment in Pigs.

Attachment of conceptus to the endometrial luminal epithelium (LE) is a critical event for early placentation in Eutheria. Since the attachment occurs at a particular site within the uterus, a coordinated communication between three spatially distinct compartments (conceptus and endometrial LE from two anatomical regions of the uterus to which conceptus attaches and does not attach) is essential but remains to be fully characterized. Using the laser capture microdissection (LCM) technique, we firstly developed an approach that can allow us to pair the pig conceptus sample with its nearby endometrial epithelium sample without losing the native spatial information. Then, a comprehensive spatio-temporal transcriptomic profile without losing the original conceptus-endometrium coordinates was constructed. The analysis shows that an apparent difference in transcriptional responses to the conceptus exists between the endometrial LE from the two anatomically distinct regions in the uterus. In addition, we identified the communication pathways that link the conceptus and endometrial LE and found that these pathways have important roles in conceptus attachment. Furthermore, a number of genes whose expression is spatially restricted in the two different anatomical regions within the uterus were characterized for the first time and two of them (SULT2A1 and MEP1B) may cooperatively contribute to establish conceptus attachment in pigs. The results from our study have implications in understanding of conceptus/embryo attachment in pigs and other large polytocous species.

Obesity and IVF: weighing in on the evidence.

Obesity is associated with serious health risks, and its rising prevalence represents a growing public health emergency. Ongoing research into the association of obesity and assisted reproductive technology (ART) outcomes aims to disentangle selective detrimental effects of obesity on the oocyte and the endometrium. More translational studies involving women with severe obesity and in the third-party reproduction setting will help improve the standard of care in the provision of ART services for obese patients.

Detection of early placental hormone production in embryo transfer cycles lacking a corpus luteum.

PURPOSE: This study sought to identify the initiation of placental hormonal production as defined by the production of endogenous estradiol (E2) and progesterone (P4) in a cohort of patients undergoing programmed endometrial preparation cycles with single embryo transfers resulting in live-born singletons. METHODS: In this retrospective cohort study, patients undergoing either programmed frozen-thawed embryo transfer (FET) with autologous oocytes or donor egg recipient (DER) cycles with fresh embryos were screened for inclusion. Only patients who underwent a single embryo transfer, had a single gestational sac, and a resultant live-born singleton were included. All patients were treated with E2 patches and intramuscular progesterone injections. Main outcome measures were serial E2 and P4, with median values calculated for cycle days 28 (baseline), or 4w0d gestational age (GA), through 60, or 8w4d GA. The baseline cycle day (CD) 28 median value was compared to each daily median cycle day value using the Wilcoxon signed rank test. RESULTS: A total of 696 patients, 569 using autologous oocytes in programmed FET cycles and 127 using fresh donor oocytes, from 4/2013 to 4/2019 met inclusion criteria. Serum E2 and P4 levels stayed consistent initially and then began to increase daily. Compared to baseline CD 28 E2 (415 pg/mL), the serum E2 was significantly elevated at 542 pg/mL (P < 0.001) beginning on CD 36 (5w1d GA). With respect to baseline CD 28 P4 (28.1 ng/mL), beginning on CD 48 (6w6d GA), the serum P4 was significantly elevated at 31.6 ng/mL (P < 0.001). CONCLUSION: These results demonstrate that endogenous placental estradiol and progesterone production may occur by CD 36 and CD 48, respectively, earlier than traditionally thought.

The impact of timing modified natural cycle frozen embryo transfer based on spontaneous luteinizing hormone surge.

PURPOSE: To evaluate whether adjusting timing of modified natural cycle frozen embryo transfer (mNC-FET) 1 day earlier in the setting of a spontaneous LH surge has an impact on pregnancy outcomes. METHODS: This retrospective cohort study evaluated all mNC-FET with euploid blastocysts from May 1, 2016 to March 30, 2019, at a single academic institution. Standard protocol for mNC-FET included ultrasound monitoring and hCG trigger when the dominant follicle and endometrial lining were appropriately developed. Patients had serum LH, estradiol, and progesterone checked on day of trigger. If LH was ≥ 20 mIU/mL, trigger was given that day and FET was performed 6 days after surge (LH/HCG+6), with the intent of transferring 5 days after ovulation. If LH was < 20 mIU/mL, FET was performed 7 days after trigger (hCG+7). Primary outcomes included clinical pregnancy and live birth rates. To account for correlation between cycles, a generalized estimating equation (GEE) method for multivariable logistic regression was used. RESULTS: Four hundred fifty-three mNC-FET cycles met inclusion criteria, of which 205 were in the LH/HCG+6 group and 248 were in the HCG+7 group. The overall clinical pregnancy rate was 64% and clinical miscarriage rate was 4.8%, with similar rates between the two groups. The overall live birth rate was 60.9% (61.0% in LH/HCG+6 group and 60.9% in HCG+7 group). After implementing GEE, the odds of CP (aOR 0.97, 95% CI [0.65-1.45], p = 0.88) and LB (aOR 0.98, 95% CI [0.67-1.45], p = 0.93) were similar in both groups. CONCLUSIONS: In our study cohort, mNC-FET based on LH/HCG+6 versus HCG+7 had similar pregnancy outcomes.

miR-34a/c induce caprine endometrial epithelial cell apoptosis by regulating circ-8073/CEP55 via the RAS/RAF/MEK/ERK and PI3K/AKT/mTOR pathways.

microRNAs (miRNAs) and circular RNAs (circRNAs) are important for endometrial receptivity establishment and embryo implantation in mammals. miR-34a and miR-34c are highly expressed in caprine receptive endometrium (RE). Herein, the functions and mechanisms of miR-34a/c in caprine endometrial epithelial cell (CEEC) apoptosis and RE establishment were investigated. miR-34a/c downregulated the expression level of centrosomal protein 55 (CEP55) and were sponged by circRNA8073 (circ-8073), thereby exhibiting a negative interaction in CEEC. miR-34a/c induced CEEC apoptosis by targeting circ-8073/CEP55 through the regulation of the RAS/RAF/MEK/ERK and phosphoitide 3-kinase (PI3K)/protein kinase B (AKT)/mammalian target of rapamycin (mTOR) pathways. Positive and negative feedback loops and cross-talk were documented between the RAS/RAF/MEK/ERK and PI3K/AKT/mTOR pathways. miR-34a/c regulated the levels of RE marker genes, including forkhead box M1, vascular endothelial growth factor, and osteopontin (OPN). These results suggest that miR-34a/c not only induce CEEC apoptosis by binding to circ-8073 and CEP55 via the RAS/RAF/MEK/ERK and PI3K/AKT/mTOR pathways, but may also regulate RE establishment in dairy goats.

Evidence from three cohort studies on the expression of MUC16 around the time of implantation suggests it is an inhibitor of implantation.

PURPOSE: To examine the expression of MUC16 in the endometrium peri-implantation period in three different cohort studies. METHODS: This was a retrospective observational cohort study. A total of 245 participants were recruited in three separate cohort studies: (1) women with recurrent miscarriage (n = 50) and fertile controls (n = 29); (2) women who had high (n = 20) or normal (n = 20) progesterone on the day of hCG trigger in ovarian stimulation cycle for IVF; and (3) women who did (n = 95) or did not (n = 31) conceive following frozen embryo transfer in HRT cycles. All subjects had archived endometrial samples precisely taken on LH+7 in natural cycles, or hCG+6 in ovarian stimulation cycles, or P+5 in HRT cycles. The H-score (median, range) of MUC16 in the luminal epithelium and glandular epithelium was determined by using immunohistochemistry. RESULTS: The median (range) of H-score of MUC16 in the luminal epithelium (1) in women with recurrent pregnancy loss was 23.7 (0-300), which was significantly (P < 0.05) lower than that of 118.4 (7.7-300) in fertile controls; (2) in women with elevated progesterone on the day of hCG administration (147.8, 18.0-230.1), significantly (P < 0.05) higher than that of women with normal progesterone (61.0, 2.3-205.3); (3) in women who conceived (23.1, 0-250.3), significantly (P < 0.001) lower than that in women who did not conceive (58.4, 0-300). CONCLUSION: The expression of MUC16 in all three cohort studies is consistent with it being an inhibitor of implantation.

Upregulation of Toll-like receptor 4 through anti-miR-Let-7a enhances blastocyst attachment to endometrial cells in mice.

Despite encouraging advances in fertility technology, the success rate of an ongoing pregnancy is relatively low and predominantly associated with implantation failure. Inflammatory responses are beneficial in the fetomaternal interface and supposedly accelerate the chances for successful implantation. The current study aims to determine the effect of Toll-like receptor 4 (TLR4) overexpression in mouse blastocysts via Let-7a downregulation using intracytoplasmic sperm injection-sperm-mediated gene transfer on embryo attachment rate. The pLenti-III-GFP-miR-Off-Let-7a vector was transmitted to oocytes derived via in vitro maturation (IVM) and in vivo oocytes by using NaOH-treated spermatozoa. Let-7a and TLR4 expression levels were evaluated by quantitative real-time polymerase chain reaction (qRT-PCR), immunocytochemistry, and western blot analysis in both oocytes and embryos. Blastocyst adhesion on the endometrial cells was monitored by microscopic analysis. qRT-PCR results showed that Let-7a expression decreased in the IVM (GV-MII) oocytes compared to the in vivo oocyte (MII) group (p < .05). TLR4 showed a higher expression in GV-MII oocytes at both the gene and protein levels (p < .05). Following anti-miR-Let-7a transmission, the TLR4 expression level was significantly upregulated in embryos compared with the control groups (p < .05). Attachment and migration of trophoblasts cells towards endometrial cells dramatically increased compared to the control group (p < .05). Based on our results, we concluded that Let-7a might mediate embryo attachment through regulation of TLR4 expression levels.

Early pregnancy loss: the default outcome for fertilized human oocytes.

Early pregnancy loss is by far the most frequent outcome of human reproduction. It occurs when despite the timely interaction of gametes and initiation of embryogenesis and implantation of the conceptus, pregnancy continuance fails. From a clinical perspective, early pregnancy loss represents a neglected but relevant issue because of the high incidence, the evolving and yet not fully elucidated mechanism, the possible association with other relevant medical conditions, and the potential psychological sequelae. Our growing understanding of the dialog established between the embryo and the endometrium provides new insights into the etiology of pregnancy loss. Aneuploidies as a cause of early pregnancy loss are known for a long time, but there is now evidence that endometrium is not a passive player. An active selection aimed at impeding implantation of unhealthy embryos actually occurs at the endometrial interface. The concept of selectivity is substituting the one of mere receptivity.

Adenosine-5'-triphosphate suppresses proliferation and migration capacity of human endometrial stem cells.

Extracellular ATP through the activation of the P2X and P2Y purinergic receptors affects the migration, proliferation and differentiation of many types of cells, including stem cells. High plasticity, low immunogenicity and immunomodulation ability of mesenchymal stem cells derived from human endometrium (eMSCs) allow them to be considered a prominent tool for regenerative medicine. Here, we examined the role of ATP in the proliferation and migration of human eMSCs. Using a wound healing assay, we showed that ATP-induced activation of purinergic receptors suppressed the migration ability of eMSCs. We found the expression of one of the ATP receptors, the P2X7 receptor in eMSCs. In spite of this, cell activation with specific P2X7 receptor agonist, BzATP did not significantly affect the cell migration. The allosteric P2X7 receptor inhibitor, AZ10606120 also did not prevent ATP-induced inhibition of cell migration, confirming that inhibition occurs without P2X7 receptor involvement. Flow cytometry analysis showed that high concentrations of ATP did not have a cytotoxic effect on eMSCs. At the same time, ATP induced the cell cycle arrest, suppressed the proliferative and migration capacity of eMSCs and therefore could affect the regenerative potential of these cells.