Production and physiological function of granulocyte colony-stimulating factor in non-pregnant human endometrial stromal cells

Recombinant human granulocyte colony stimulating factor (rhG-CSF) participates in the progression of implantation via the hsa_circ_0001550-miRNA-mRNA interaction network

Inadequate endometrial receptivity is a key factor affecting the successful implantation of embryos. Recombinant human granulocyte colony stimulating factor (rhG-CSF) can increase endometrial thickness and improve the outcomes of assisted reproductive technologies (ARTs). In this preliminary study, the function and possible molecular mechanisms of recombinant human granulocyte colony stimulating factor (rhG-CSF) which affects endometrial receptivity and implantation in human Embryonic Stem Cells (hESCs) were investigated. The cell viability of endometrial stromal cells treated with rhG-CSF 0.5 ng/ml for 24 h was significantly increased. Moreover, the expression of hsa_circ_0001550 was downregulated in endometrial stromal cells treated with rhG-CSF. Furthermore, the hsa_circ_0001550-miRNA-mRNA network was constructed and the downstream target genes (including 4 miRNAs and 117 mRNAs) of hsa_circ_0001550 were mainly involved in the cAMP and calcium signalling pathways, which play important roles in regulating endometrial receptivity and embryo implantation. We conclude that rhG-CSF participates in the regulation of embryo implantation by regulating the hsa_circ_0001550-miRNA-mRNA interaction network.

Treatment options for endometrial hypoproliferation

PURPOSE OF REVIEW

Endometrial hypoproliferation refers to the failure of the endometrium to reach optimal thickness during fresh or frozen embryo transfer cycles in women undergoing infertility treatment with in-vitro fertilization (IVF). This review discusses the treatment options for endometrial hypoproliferation.

RECENT FINDINGS

Apart from factors related to the embryo quality, ultrasonographic findings associated with the endometrium, such as endometrial thickness, endometrial pattern and subendometrial blood flow, are considered key factors associated with the outcome of assisted reproductive treatment. To date, a consensus has not been reached regarding the definition of thin endometrium, while thresholds of 6, 7 or 8 mm have been used in the literature. Strategies to increase endometrial thickness can be reviewed in three groups: endocrine approaches, vitamins & supplements, and new experimental therapeutic interventions. Some of the recently introduced experimental therapeutic interventions such as platelet-rich plasma injection, stem cell treatment and tissue bioengineering are exciting potential therapies that need to be further studied.

SUMMARY

Despite a large number of publications on the topic, diagnosing and treating endometrial hypoproliferation remains a challenge. Well designed studies are needed to establish a widely accepted endometrial thickness cut-off value below which endometrial hypoproliferation is diagnosed and to generate meaningful data that would allow an evidence-based discussion of available therapeutic options with patients.

Granulocyte colony-stimulating factor in reproductive-related disease: Function, regulation and therapeutic effect

Granulocyte colony-stimulating factor (G-CSF) is one of the cytokines which plays important roles in embryo implantation and normal pregnancy. At the maternal-fetal interface, G-CSF can be synthesized by multiple cells, and participates in regulation of trophoblast development, endometrial decidualization, placental metabolism and angiogenesis. Moreover, as an important medium of intercellular communication, G-CSF has also been shown to exert key roles in crosstalk between cellular components at the maternal-fetal interface. Recently, our study demonstrated that G-CSF derived from M2 macrophage could promote trophoblasts invasion and migration through activating PI3K/AKT/Erk1/2 pathway, thereby involving in normal pregnancy program. Herein, we will summarize the role and regulation of G-CSF in normal pregnancy and reproductive-related disease, and the clinical applications of G-CSF in patients undergoing in vitro fertilization with thin endometrium, repeated implantation failure, and women suffered with recurrent spontaneous abortion.

3D-printed hydrogel scaffold-loaded granulocyte colony-stimulating factor sustained-release microspheres and their effect on endometrial regeneration

After injury, the endometrium cannot self-repair or regenerate because damages of the basal layer of the uterine, which often lead to intrauterine adhesions (IUAs), which can cause serious problems such...

Functional changes of immune cells: signal of immune tolerance of the ectopic lesions in endometriosis?

RESEARCH QUESTION

What is the potential role of immune cells and their inflammatory cytokines in the pathogenesis, development and establishment of endometriosis?

DESIGN

Peritoneal fluid from 59 women (43 with endometriosis and 16 controls) who had undergone laparoscopic surgery was analysed. Changes in the population of innate and adaptive immune cells, cytokines, chemokines and growth factor expression were measured by flow cytometry, Luminex Technology and enzyme-linked immunosorbent assay.

RESULTS

No differences were found in the frequencies of the innate and adaptive immune cells between women with and without endometriosis. In the peritoneal fluid of women with endometriosis, IL-1β, IL-1RN, IL-2, IL-4, IL-8, IL-10, IL-12 (p70), IL-17α, FGF2, G-CSF, MCP-1, MIP-1α and TNF-α were significantly increased compared with controls. A correlation between IL-2, MCP-1, MIP-1α, TNF-α and the severity of endometriosis was observed. The concentration of neopterin, a possible biomarker for this disease, was increased in women with endometriosis compared with controls.

CONCLUSIONS

The functional activity of immune cells seemed to be reduced despite their numbers remaining unchanged. The data indicate that a shift of T_H cytokine profile occurs, which increases the T_H1-T_H2 ratio. This is driven by the increased levels of the cytokines (TNF-α and IL-2) in women with severe endometriosis.

Endometrial stromal cell inflammatory phenotype during severe ovarian endometriosis as a cause of endometriosis-associated infertility

RESEARCH QUESTION

Do endometrial stromal cells from primary infertile patients with severe ovarian endometriosis display differential secretory profiles of inflammation-associated cytokines during the implantation window that may cause infertility?

DESIGN

Forty-eight cytokines were measured in conditioned medium of isolated endometrial stromal cells obtained from primary infertile patients without endometriosis (control group, n = 12) or with stage IV ovarian endometriosis (ovarian endometriosis group, n = 14) using multiplex assays. Key cytokines showing differential secretory profiles were validated using Western immunoblotting. Cellular phenotypic validation was carried out in vitro by comparing proliferation and migration capacity between control (n = 6) and ovarian endometriosis (n = 7) groups.

RESULTS

CCL3, CCL4, CCL5, CXCL10, FGF2, IFNG, IL1RN, IL5, TNFA, and VEGF could be detected only in the conditioned media of stromal cells obtained from the ovarian endometriosis group. Among other cytokines detected in the conditioned media of both groups, CCL2 (P = 0.0018), CSF3 (P = 0.0017), IL1B (P = 0.0066), IL4 (P = 0.036), IL6 (P = 0.0039) and IL13 (P = 0.036) were found to be higher, whereas the concentration of IL18 was lower (P = 0.023) in the ovarian endometriosis group. Concentrations of CCL2, IL1B, IL4 and IL13 in conditioned medium reflected significant diagnostic performance for predicting ovarian endometriosis. Cellular phenotypic validation in vitro revealed an enhanced proliferative phenotype (P = 0.046) with no change in cell migratory capacity of endometrial stromal cells from the ovarian endometriosis group.

CONCLUSIONS

Endometrial stromal cells derived from severe ovarian endometriosis samples displayed a hyperinflammatory and hyperproliferative bias in the endometrial stroma during the 'window of implantation' putatively causing loss of fecundability.

Evaluation of granulocyte colony-stimulating factor on the treatment of thin endometrium during frozen-thawed embryo transfer cycles: a retrospective cohort study

The aim of this study was to evaluate the effect of granulocyte colony-stimulating factor (G-CSF) on thin endometrium (≤7 mm) in women undergoing frozen-thawed embryo transfer (FET). This retrospective cohort study includes 271 infertile patients with thin endometrium. 117 patients who received intrauterine perfusion of G-CSF before the day of administration of progesterone were defined as G-CSF group, whereas 154 patients who refused to use G-CSF treatment were defined as control group. In the G-CSF group, significantly higher endometrial thickness was observed after G-CSF perfusion (p < .001). When we divided the G-CSF group into two subgroups according to whether they conceived, the endometrial thickness increased from 6.02 ± 0.92 mm to 6.98 ± 1.20 mm in the conception group (p < .001) and from 6.21 ± 0.96 mm to 6.87 ± 1.16 mm in the non-conception group (p < .001). However, there were no significant differences between the two subgroups in respect to the endometrial thickness both before and after G-CSF perfusion. The implantation rate, hCG positive rate and clinical pregnancy rate were similar between G-CSF group and control group. Thus, our study fails to demonstrate that G-CSF has the potential to improve pregnancy outcome but has the potential to increase endometrial thickness of the women with thin endometrium in FET cycles.

Intrauterine G-CSF Administration in Recurrent Implantation Failure (RIF): An Rct

This study investigates the effects of intrauterine G-CSF on endometrial thickness, clinical pregnancy rate and live birth rate in a recurrent implantation failure (RIF) group with normal endometrium. This study was designed as a prospective randomized controlled trial with the involvement of 157 RIF group pati; ents. The RIF group was formed on the basis of the RIF criteria: "The failure to achieve a clinical pregnancy after the transfer of at least four good-quality embryos in a minimum of three fresh or frozen cycles to a woman under the age of 40 years. The study sample included 82 patients in the G-CSF group who received G-CSF once a day on hCG. The procedure was performed by administering 30 mIU of Leucostim®(Filgrastim [G-CSF] 30 mIU/mL; DEM Medical, Dong-A; South Korea) through slow infusion into the endometrial cavity using a soft embryo transfer catheter. Normal saline of 1 mL was infused into the endometrial cavity in the same way in 75 patients in the control group. The standard ICSI procedure was used for all patients, and fresh cycle embryos were transferred on the third or fifth day. No statistically significant difference was identified in clinical pregnancy rates, miscarriage rates and live birth rates between the G-CSF group and the control group (p = 0.112, p = 0.171, p = 0.644, respectively), and no difference was observed between the two groups regarding endometrial thickness (p = 0.965). The intervention of administration G-CSF into the uterine cavity in RIF patients with normal endometrium, did not alter the endometrial thickness, clinical pregnancy rates, or live birth rates.

Granulocyte-colony stimulating factor administration for subfertile women undergoing assisted reproduction

BACKGROUND

Granulocyte-colony stimulating factor (G-CSF) seems to play an important role in the process of embryo implantation and continuation of pregnancy. It has been used during in vitro fertilisation (IVF) treatment for subfertile women with chronically thin endometrium and those with previous multiple IVF failures. It is currently unknown whether G-CSF is effective in improving results following assisted reproductive technology (ART).

OBJECTIVES

To evaluate the effectiveness and safety of G-CSF in women undergoing ART.

SEARCH METHODS

We searched the Cochrane Gynaecology and Fertility Group Specialised Register, CENTRAL, MEDLINE, Embase, ClinicalTrials.gov, and the World Health Organization International Clinical Trials Registry Platform in February 2019. We searched reference lists of relevant articles and handsearched relevant conference proceedings.

SELECTION CRITERIA

Randomised controlled trials (RCTs) comparing G-CSF administration versus no treatment or placebo in subfertile women undergoing IVF treatment.

DATA COLLECTION AND ANALYSIS

Two review authors independently screened studies, extracted data, and assessed risk of bias. The primary outcomes were live-birth rate and miscarriage rate following G-CSF administration. We have reported ongoing pregnancy rate in cases where studies did not report live birth but reported ongoing pregnancy. Secondary outcomes were clinical pregnancy rate, multiple pregnancy rate, adverse events, ectopic pregnancy rate, small for gestational age at birth, abnormally adherent placenta, and congenital anomaly rate. We analysed data using risk ratio (RR), Peto odds ratio and a fixed-effect model. We assessed the quality of the evidence using the GRADE criteria.

MAIN RESULTS

We included 15 trials involving 622 women who received G-CSF and 631 women who received placebo or no additional treatment during IVF. The main limitations in the quality of the evidence were inadequate reporting of study methods and high risk of performance bias due to lack of blinding. We assessed only two of the 15 included trials as at a low risk of bias. None of the trials reported the primary effectiveness outcome of live-birth rate. We are uncertain whether G-CSF administration improves ongoing pregnancy rate compared to control in subfertile women undergoing ART (RR 1.42, 95% confidence interval (CI) 0.83 to 2.42; 2 RCTs; participants = 263; I² = 0%; very low-quality evidence). For a typical clinic with 14% ongoing pregnancy rate, G-CSF administration would be expected to result in ongoing pregnancy rates between 12% and 35%. We are uncertain whether G-CSF administration reduces miscarriage rate (Peto odds ratio 0.55, 95% CI 0.17 to 1.83; 3 RCTs; participants = 391; I² = 0%; very low-quality evidence) compared to the control group in subfertile women undergoing ART. We are uncertain whether G-CSF administration improves overall clinical pregnancy rate compared to control in subfertile women undergoing ART (RR 1.63, 95% CI 1.32 to 2.01; 14 RCTs; participants = 1253; I² = 13%; very low-quality evidence). For a typical clinic with 17% clinical pregnancy rate, G-CSF administration would be expected to result in clinical pregnancy rates between 23% and 35%. In the unselected IVF population, we are uncertain whether G-CSF administration improves clinical pregnancy rate compared to the control group (RR 1.11, 95% CI 0.77 to 1.60; 3 RCTs; participants = 404; I² = 0%; low-quality evidence). G-CSF administration may improve clinical pregnancy rate in women with two or more previous IVF failures compared to the control group (RR 2.11, 95% CI 1.56 to 2.85; 7 RCTs; participants = 643; I² = 0%; low-quality evidence). In subfertile women with thin endometrium undergoing ART, we are uncertain whether G-CSF administration improves clinical pregnancy rate compared to the control group (RR 1.58, 95% CI 0.95 to 2.63; 4 RCTs; participants = 206; I² = 30%; low-quality evidence). No study reported on multiple pregnancy rate. Only four trials reported adverse events as an outcome, and none of them reported any major adverse events following either G-CSF administration or placebo/no treatment.

AUTHORS' CONCLUSIONS

In subfertile women undergoing ART, we are uncertain whether the administration of G-CSF improves ongoing pregnancy or overall clinical pregnancy rates or reduces miscarriage rate compared to no treatment or placebo, whether in all women or those with thin endometrium, based on very low-quality evidence. Low-quality evidence suggests that G-CSF administration may improve clinical pregnancy rate in women with two or more IVF failures, but the included studies had unclear allocation concealment or were at high risk of performance bias.

Granulocyte‐colony stimulating factor administration for subfertile women undergoing assisted reproduction

This is a protocol for a Cochrane Review (Intervention). The objectives are as follows:

To evaluate the effectiveness and safety of granulocyte‐colony stimulating factor in women undergoing ART.

Effect of Increased Endometrial Thickness and Implantation Rate by Granulocyte Colony-Stimulating Factor on Unresponsive Thin Endometrium in Fresh In Vitro Fertilization Cycles: A Randomized Clinical Trial

BACKGROUND

The correlation between endometrial thickness and receptivity has been mentioned in various studies. This study investigated the effect of granulocyte colony-stimulating factor in treating thin endometrium of infertile women who were chosen for in vitro fertilization in our infertility clinic in 2014 and 2015.

METHODS

In this randomized clinical trial, 28 women who were chosen for in vitro fertilization and had endometrial thickness of less than 6 mm on the day of human chorionic gonadotropin (hCG) injection were included in the study. They were randomly divided into two groups: investigation and control groups. In investigation group (n = 13) one granulocyte colony-stimulating factor vial (300 micrograms in 1 mL) was infused into the uterus within five minutes by embryo transfer catheter. In control group (n = 15) 1 mL of saline was injected into the uterus with the same catheter.

RESULTS

There were significant differences between the two groups in terms of means of endometrial thickness on oocyte retrieval day (P = 0.001), embryo transfer day (P = 0.001), hCG injections (P = 0.001), and implantation rates (P = 0.001).

CONCLUSION

Granulocyte colony-stimulating factor can increase endometrial thickness in women treated with in vitro fertilization. RCT Code is 201406046063N2.

The efficacy of intrauterine instillation of granulocyte colony-stimulating factor in infertile women with a thin endometrium: A pilot study

Objective

The study aimed to investigate the efficacy of intrauterine instillation of granulocyte colony-stimulating factor (G-CSF) on the day of ovulation triggering or oocyte retrieval in infertile women with a thin endometrium.

Methods

Fifty women whose endometrial thickness (EMT) was ≤8 mm at the time of triggering during at least one previous in vitro fertilization (IVF) cycle and an index IVF cycle were selected. On the day of triggering (n=12) or oocyte retrieval (n=38), 300 µg of G-CSF was instilled into the uterine cavity.

Results

In the 50 index IVF cycles, the mean EMT was 7.2±0.6 mm on the triggering day and increased to 8.5±1.5 mm on the embryo transfer day (p<0.001). The overall clinical pregnancy rate was 22.0%, the implantation rate was 15.9%, and the ongoing pregnancy rate was 20%. The clinical pregnancy rate (41.7% vs. 15.8%), the implantation rate (26.7% vs. 11.7%), and the ongoing pregnancy rate (41.7% vs. 13.2%) were higher when G-CSF was instilled on the triggering day than when it was instilled on the retrieval day, although this tendency was likewise not statistically significant. Aspects of the stimulation process and mean changes in EMT were similar in women who became pregnant and women who did not.

Conclusion

Intrauterine instillation of G-CSF enhanced endometrial development and resulted in an acceptable pregnancy rate. Instillation of G-CSF on the triggering day showed better outcomes. G-CSF instillation should be considered as a strategy for inducing endometrial growth and good pregnancy results in infertile women with a thin endometrium.

Whether G-CSF administration has beneficial effect on the outcome after assisted reproductive technology? A systematic review and meta-analysis

BACKGROUND

Previous studies have explored the effect of granulocyte colony stimulating factor (G-CSF) administration on the outcome of assisted reproductive technology (ART), and came into controversial conclusions. The present meta-analysis aims to assess whether G-CSF administration has beneficial effect on the outcome after ART.

METHOD

The electronic databases Pubmed, Embase and Google Scholar were searched up to May 2016. Articles that studied the effect of G-CSF administration on the outcome after ART were included in the present meta-analysis. Odds ratio (OR) with 95 % confidence interval (95 % CI) were calculated to assess the effect of G-CSF administration on the outcome after ART. The outcomes of interest were implantation rate (IR) and pregnancy rate (PR).

RESULTS

Four cohort studies with 1101 embryos transplantation assessed the effect of G-CSF administration on IR and 6 studies with 621 cycles assessed the role of G-CSF administration in PR. Meta-analysis did not found an increased embryo IR in G-CSF administration cycles [OR 1.59 (95 % CI 0.74-3.41). whereas the PR with G-CSF administration was significantly higher compared with cases without G-CSF administration [OR 2.03 (95 % CI 1.19-3.46)]. Additionally, we found that G-CSF administrated subcutaneously resulted in significantly higher PR [OR 3.12 (95 % CI 1.67-5.81)] and IR [OR 2.82 (95 % CI 1.29-6.15)] compared with control group, whereas G-CSF administrated via local uterine infusion had no beneficial effect on the PR [OR 1.42 (95 % CI 0.91-2.24)] and IR [OR 1.10 (95 % CI 0.76-1.60)] after ART.

CONCLUSIONS

G-CSF administration may have beneficial effect on clinical pregnancy outcome after ART. Subcutaneous injection may be an optimal route of G-CSF administration. Further cohort studies are required to explore the mechanisms undergone the effect and investigate the best route and dose of G-CSF administration.

Effects of Granulocyte Colony-Stimulating Factor (GCSF) on Persistent Thin Endometrium in Frozen Embryo Transfer (FET) Cycles

OBJECTIVE

To predict the effectiveness of granulocyte colony-stimulating factor (GCSF) in the treatment of persistent thin endometrium resistant to other treatments in frozen embryo transfer (FET) cycles.

STUDY DESIGN

This is a hospital-based prospective study.

PATIENTS

Thirty-five women with persistent thin endometrium (<7 mm) resistant to standard treatments were involved in this study.

INTERVENTIONS

Intrauterine infusion of GCSF (300 mcg/1 ml) was done in patients with thin endometrium on day 14 of FET cycles, and their endometrial thicknesses were measured after 48 h of infusion.

MAIN OUTCOME MEASURES

The primary outcome was an increase in endometrial thickness and the secondary outcome measures were chemical and clinical pregnancies.

RESULTS

The endometrial thickness increased from 5.86 ± 0.58 to 6.58 ± 0.84 mm after GCSF infusion. In 19 of the 35 participants (54.28 %) endometrial thickness increased to ≥7 mm and they subsequently underwent embryo transfer. Of these, 3 (15.78 %) patients had chemical pregnancy, but there was no clinical pregnancy. In 16 participants, embryo transfer was canceled in view of insufficient endometrial thickness (<7 mm).

CONCLUSION

GCSF caused a small increase in endometrial thickness in women with persistent thin endometrium, but there was no improvement in their pregnancy rates.

Profiles of cytokines secreted by isolated human endometrial cells under the influence of chorionic gonadotropin during the window of embryo implantation

BACKGROUND

Several studies have indicated that human pre-implantation embryo-derived chorionic gonadotropin (hCG) may influence the implantation process by its action on human endometrial epithelial and stromal cells. Despite reports indicating that hCG acts on these cells to affect the production of several cytokines and growth factors (e.g., MIF, IGF-I, VEGF, LIF, IL-11, GMCSF, CXL10 and FGF2), our understanding of the integral influence of hCG on paracrine interactions between endometrial stromal and epithelial cells during implantation is very limited.

METHODS

In the present study, we examined the profile of 48 cytokines in the conditioned media of primary cell cultures of human implantation stage endometrium. Endometrial epithelial cells (group 1; n = 20), stromal cells (group 2; n = 20), and epithelial plus stromal cells (group 3; n = 20) obtained from mid-secretory stage endometrial samples (n = 60) were grown on collagen and exposed to different doses (0, 1, 10 and 100 IU/ml) of rhCG for 24 h in vitro. Immunochemical and qRT-PCR methods were used to determine cytokine profiles. Enrichment and process networks analyses were implemented using a list of cytokines showing differential secretion in response to hCG.

RESULTS

Under basal conditions, endometrial epithelial and stromal cells exhibited cell type-specific profiles of secreted cytokines. Administration of hCG (100 IU) resulted in significantly (P < 0.05) different cytokine secretion profiles indicative of macropinocytic transport (HGF, MCSF) in epithelial cells, signal transduction (CCL4, FGF2, IL-1b, IL-6, IL-17, VEGF) in stromal cells, and epithelial-mesenchymal transition (FGF2, HGF, IL-1b, TNF) in mixed cells. Overall, the administration of hCG affected cytokines involved in the immune response, chemotaxis, inflammatory changes, proliferation, cell adhesion and apoptosis.

CONCLUSIONS

CG can influence the function of the endometrium during blastocyst implantation via its differential action on endometrial epithelial and stromal cells. CG may also affect complex paracrine processes in the different endometrial cell types.

A pilot cohort study of granulocyte colony-stimulating factor in the treatment of unresponsive thin endometrium resistant to standard therapies

STUDY QUESTION

Is thin endometrium unresponsive to standard treatments expandable by intrauterine perfusion with granulocyte colony-stimulating factor (G-CSF)?

SUMMARY ANSWER

This cohort study is supportive of the effectiveness of G-CSF in expanding chronically unresponsive endometria.

WHAT IS KNOWN ALREADY

In a previous small case series, we reported the successful off-label use of G-CSF in four consecutive patients, who had previously failed to expand their endometria beyond 6.9 mm with the use of standard treatments.

STUDY DESIGN, SIZE AND DURATION

In a prospective observational cohort pilot study over 18 months, we described 21 consecutive infertile women with endometria <7 mm on the day of hCG administration in their first IVF cycles at our center. All previous cycles using traditional treatments with estradiol, sildenafil citrate (Viagra™) and/or beta-blockers had been unsuccessful. G-CSF (Nupogen™) was administered per intrauterine catheter by slow infusion before noon on the day of hCG administration. If the endometrium had not reached at least a 7-mm within 48h, a second infusion was given following oocyte retrieval. Primary and secondary main outcomes were an increase in endometrial thickness and clinical pregnancy, respectively. Endometrial thickness was assessed by vaginal ultrasound at the most expanded area of the endometrial stripe.

PARTICIPANTS/MATERIALS, SETTINGS AND METHOD

This study was uncontrolled, each patient serving as her own control in a prospective evaluation of endometrial thickness. The mean ± SD age of the cohort was 40.5 ± 6.6 years, gravidity was 1.8 ± 2.1 (range 0-7) and parity was 0.4 ± 1.1 (range 0-4); 76.2% of women had, based on age-specific FSH and anti-Müllerian hormone, an objective diagnosis of diminished ovarian reserve and had failed 2.0 ± 2.1 prior IVF cycles elsewhere.

MAIN RESULTS AND THE ROLE OF CHANCE

With 5.2 ± 1.9 days between G-CSF perfusions and embryo transfers, endometrial thickness increased from 6.4 ± 1.4 to 9.3 ± 2.1 mm (P < 0.001). The Δ in change was 2.9 ± 2.0 mm, and did not vary between conception and non-conception cycles. A 19.1% ongoing clinical pregnancy rate was observed, excluding one ectopic pregnancy.

LIMITATIONS AND REASONS FOR CAUTION

Small sample size (but a highly selected patient population) in an uncontrolled cohort study and in unselected first IVF cycles at our center.

WIDER IMPLICATIONS OF THE FINDINGS

This pilot study supports the utility of G-CSF in the treatment of chronically thin endometrium and suggests that such treatment will, in very adversely affected patients, result in low but very reasonable clinical pregnancy rates.

STUDY FUNDING/COMPETING INTEREST(S)

This work was supported by the Foundation for Reproductive Medicine, New York, New York, USA, a not-for-profit research foundation and intramural grants from the Center for Human Reproduction (CHR)-New York. N.G. and D.H.B. are members of the board of the Foundation for Reproductive Medicine. N.G. is owner of CHR-New York, where the study was conducted. N.G. and D.H.B. have been recipients of research awards, travel grants and speaker honoraria from various pharmaceutical and medical device companies. None of these companies was, however, in any way associated with the materials and the manuscript presented here. N.G. and D.H.B. are listed as co-inventors on a number of awarded and still pending U.S. patents, none related to the materials presented here. N.G. is on the board of a medically related company, not in any way associated with the data presented here.

Decidualization of the human endometrial stromal cell: an enigmatic transformation

Changes in human endometrium are essential to allow the establishment of pregnancy. These changes are induced in vivo by progesterone, and include appearance within the tissue of a specific uterine natural killer cell, characterized by an abundant expression of CD56. Changes also occur in the stromal cells, which undergo a characteristic decidualization reaction. Decidualized stromal cells are derived from the fibroblast-like cells within the endometrium, which maintain their progesterone receptors in the presence of progesterone. Prolonged exposure to progesterone induces a rounded cell characterized by release of prolactin and insulin-like growth factor binding protein-1 (IGFBP-1), and expression of tissue factor. Additional changes include the secretion of interleukin (IL)-15, vascular endothelial growth factor, and surface expression of zinc dependent metalloproteinases such as CD10 and CD13. In vitro, elevated intracellular cAMP as well as progesterone is necessary for decidualization. In vivo, these conditions may be provided by progesterone from the corpus luteum, by prostaglandin E, a stimulator of adenyl cyclase, and relaxin, which has recently been shown to be a phosphodiesterase inhibitor. Given the co-distribution of uterine natural killer cells and decidualized stromal cells, a mutual interaction might provide the correct regulatory environment for successful implantation, and penetration of the maternal blood vessels by trophoblastic cells.