Mechanisms of angioregression of the corpus luteum

The corpus luteum is a transient ovarian endocrine gland that produces the progesterone necessary for the establishment and maintenance of pregnancy. The formation and function of this gland involves angiogenesis, establishing the tissue with a robust blood flow and vast microvasculature required to support production of progesterone. Every steroidogenic cell within the corpus luteum is in direct contact with a capillary, and disruption of angiogenesis impairs luteal development and function. At the end of a reproductive cycle, the corpus luteum ceases progesterone production and undergoes rapid structural regression into a nonfunctional corpus albicans in a process initiated and exacerbated by the luteolysin prostaglandin F2α (PGF2α). Structural regression is accompanied by complete regression of the luteal microvasculature in which endothelial cells die and are sloughed off into capillaries and lymphatic vessels. During luteal regression, changes in nitric oxide transiently increase blood flow, followed by a reduction in blood flow and progesterone secretion. Early luteal regression is marked by an increased production of cytokines and chemokines and influx of immune cells. Microvascular endothelial cells are sensitive to released factors during luteolysis, including thrombospondin, endothelin, and cytokines like tumor necrosis factor alpha (TNF) and transforming growth factor β 1 (TGFB1). Although PGF2α is known to be a vasoconstrictor, endothelial cells do not express receptors for PGF2α, therefore it is believed that the angioregression occurring during luteolysis is mediated by factors downstream of PGF2α signaling. Yet, the exact mechanisms responsible for angioregression in the corpus luteum remain unknown. This review describes the current knowledge on angioregression of the corpus luteum and the roles of vasoactive factors released during luteolysis on luteal vasculature and endothelial cells of the microvasculature.

Luteinizing hormone receptor promotes angiogenesis in ovarian endothelial cells of Macaca fascicularis and Homo sapiens†

Angiogenesis within the ovarian follicle is an important component of ovulation. New capillary growth is initiated by the ovulatory surge of luteinizing hormone (LH), and angiogenesis is well underway at the time of follicle rupture. LH-stimulated follicular production of vascular growth factors has been shown to promote new capillary formation in the ovulatory follicle. The possibility that LH acts directly on ovarian endothelial cells to promote ovulatory angiogenesis has not been addressed. For these studies, ovaries containing ovulatory follicles were obtained from cynomolgus macaques and used for histological examination of ovarian vascular endothelial cells, and monkey ovarian microvascular endothelial cells (mOMECs) were enriched from ovulatory follicles for in vitro studies. mOMECs expressed LHCGR mRNA and protein, and immunostaining confirmed LHCGR protein in endothelial cells of ovulatory follicles in vivo. Human chorionic gonadotropin (hCG), a ligand for LHCGR, increased mOMEC proliferation, migration and capillary-like sprout formation in vitro. Treatment of mOMECs with hCG increased cAMP, a common intracellular signal generated by LHCGR activation. The cAMP analog dibutyryl cAMP increased mOMEC proliferation in the absence of hCG. Both the protein kinase A (PKA) inhibitor H89 and the phospholipase C (PLC) inhibitor U73122 blocked hCG-stimulated mOMEC proliferation, suggesting that multiple G-proteins may mediate LHCGR action. Human ovarian microvascular endothelial cells (hOMECs) enriched from ovarian aspirates obtained from healthy oocyte donors also expressed LHCGR. hOMECs also migrated and proliferated in response to hCG. Overall, these findings indicate that the LH surge may directly activate ovarian endothelial cells to stimulate angiogenesis of the ovulatory follicle.

Granulocyte colony stimulating factor versus human chorionic gonadotropin for recurrent implantation failure in intra cytoplasmic sperm injection: a randomized clinical trial

BACKGROUND

Repeated implantation failure (RIF) is defined as the case whereby the transferred embryos fail to implant after several attempts of In vitro fertilization (IVF) which causes a profound impact on the quality of life and financial burden. Some clinical studies have confirmed that Granulocyte colony-stimulating factor (G-CSF) and human chorionic gonadotropin (HCG) can improve pregnancy outcomes and implantation rates. Hence, our study aims to compare the efficacy of G-CSF and HCG on pregnancy outcomes in RIF women who undergo intra-cytoplasmic sperm injection (ICSI).

METHODS

This randomized, single-blinded study was conducted et al.-Azhar University Hospitals, Cairo, Egypt, between 10^th October 2020 and 20^th December 2020. The study included 100 women aged 20-43 years old undergoing ICSI cycles, with a history of RIF. Patients were divided randomly into two groups: group (1): included 50 patients injected with 500 IU of intrauterine HCG on embryo transfer day, and group (2): Included 50 patients injected with G-CSF on the embryo transfer day.

RESULTS

In 100 RIF women, we found a significant improvement in pregnancy outcomes favoring G-CSF over HCG including implantation rate, chemical pregnancy, and clinical pregnancy (P < 0.0001, P = 0.0003, and P = 0.0006, respectively).

CONCLUSION

For the first time, we demonstrated a significant improvement in pregnancy outcomes favoring G-CSF over HCG in terms of implantation rate, chemical pregnancy, and clinical pregnancy.

TRIAL REGISTRATION

The study was registered on Pan African Clinical Trials Registry with the following number: PACTR202010482774275 and was approved on 2^nd October 2020.

Human Chorionic Gonadotropin and Early Embryogenesis: Review

Human chorionic gonadotropin (hCG) has four major isoforms: classical hCG, hyperglycosylated hCG, free β subunit, and sulphated hCG. Classical hCG is the first molecule synthesized by the embryo. Its RNA is transcribed as early as the eight-cell stage and the blastocyst produces the protein before its implantation. This review synthetizes everything currently known on this multi-effect hormone: hCG levels, angiogenetic activity, immunological actions, and effects on miscarriages and thyroid function.

Human Chorionic Gonadotrophin: New Pleiotropic Functions for an "Old" Hormone During Pregnancy

Human chorionic gonadotrophin (hCG) is the first specific molecule synthesized by the embryo. hCG RNA is transcribed as early as the eight-cell stage, and the blastocyst produces the protein before its implantation. hCG in the uterine microenvironment binds with its cognate receptor, luteinizing hormone/choriogonadotropin receptor (LHCGR), on the endometrial surface. This binding stimulates leukemia inhibitory factor (LIF) production and inhibits interleukin-6 (IL-6) production by epithelial cells of the endometrium. These effects ensure essential help in the preparation of the endometrium for initial embryo implantation. hCG also effects angiogenic and immunomodulatory actions as reported in many articles by our laboratories and other ones. By stimulating angiogenesis and vasculogenesis, hCG provides the placenta with an adequate maternal blood supply and optimal embryo nutrition during the invasion of the uterine endometrium. The immunomodulatory properties of hCG are numerous and important for programming maternal immune tolerance toward the embryo. The reported effects of hCG on uterine NK, Treg, and B cells, three major cell populations for the maintenance of pregnancy, demonstrate the role of this embryonic signal as a crucial immune regulator in the course of pregnancy. Human embryo rejection for hCG-related immunological reasons has been studied in different ways, and a sufficient dose of hCG seems to be necessary to maintain maternal tolerance. Different teams have studied the addition of hCG in patients suffering from recurrent miscarriages or implantation failures. hCG could also have a beneficial or a negative impact on autoimmune diseases during pregnancy. In this review, we will discuss the immunological impacts of hCG during pregnancy and if this hormone might be used therapeutically.

Aberrant endometrial steroid receptor expression in in-vitro maturation cycles despite hormonal luteal support: A pilot study

Clinical outcomes of fresh embryo transfer in non-hCG triggered in vitro maturation (IVM) cycles are inferior compared to vitrified-warmed embryo transfer. This is a prospective observational pilot study in a consecutive cohort of 31 polycystic ovary syndrome (PCOS) patients and 37 normo-ovulatory egg donors who underwent IVM without fresh embryo transfer between July 2009 and June 2014. All subjects received 150 IU of highly purified menotropin (HP-hMG) daily for three days. On cycle day 6, all patients started transdermal oestradiol (E2) at a daily dose of 9 mg. There was no human chorionic gonadotropin (hCG) trigger before oocyte retrieval (OR). Vaginal micronized progesterone was commenced on the evening after OR, at a daily dose of 600 mg. Additional luteal phase support (LPS) was administered as follows: Group A: no additional LPS; Group B: 1500 IU of hCG administered 4 h after OR and Group C: 5000 IU of hCG administered 4 h after OR + an additional injection of 5000 IU of hCG 1 day before endometrial biopsy. Endometrial biopsy for histology and immunohistochemistry (IHC) was performed on day 5 or 6 after OR. Instead of being downregulated, both PR-B and ERα in endometrial glands and stroma were moderately to strongly expressed in all three protocols, suggesting that the mid-luteal histological signature of endometrial receptivity is deficient in a non-hCG-triggered IVM cycle. Poor clinical outcomes after fresh embryo transfer following IVM are probably related to inappropriate endometrial development which may be linked to the short follicular phase of IVM cycles.

Effect of intrauterine injection of human chorionic gonadotropin before frozen-thawed embryo transfer on pregnancy outcomes in women with endometriosis

Objective

To investigate the effect of human chorionic gonadotropin (hCG) intrauterine injection before frozen–thawed embryo transfer (FET) in women with endometriosis.

Methods

This retrospective cohort study included 45 women with endometriosis who underwent hCG intrauterine injection before FET; each woman was matched with three patients with endometriosis who did not receive hCG intrauterine injection (controls). Data on pregnancy and prenatal outcomes were extracted from medical records and compared.

Results

Patients in the hCG intrauterine injection group had significantly higher rates of pregnancy and clinical pregnancy (64.4% and 57.8%, respectively) than controls (47.4% and 39.3%, respectively). Neonatal birth weight for both singletons and twins was significantly higher in the hCG group (3486 ± 458 g and 2710 ± 437 g, respectively) than in the control group (3195 ± 401 g and 2419 ± 370 g, respectively).

Conclusion

Pregnancy rate, clinical pregnancy rate, and birth weight were improved in women with endometriosis who underwent intrauterine hCG injection compared with those who did not receive hCG before FET.

Intrauterine infusion of human chorionic gonadotropin before embryo transfer in IVF/ET cycle: The critical review

Intrauterine infusion of human chorionic gonadotropin (IUI-hCG) has been proposed to improve the outcome of in vitro fertilization-embryo transfer (IVF-ET), since it plays a critical role in synchronizing endometrial and fetal development. As the early mediator from embryo, hCG promotes the decidualization, angiogenesis, maternal immune tolerance, and trophoblast invasion, favoring successful implantation of embryo. Although multiple clinical trials have been conducted to verify the efficacy of IUI-hCG on IVF-ET outcome in recent years, the findings remained controversial. The difference in study design and population might be the cause to the different consequences after administration of hCG. More importantly, the endometrial receptivity, which might affect the efficacy of IUI-hCG, has not been assessed in women receiving this intervention. Selecting the right population suitable for IUI-hCG based on known etiology would be crucial in enhancing its efficacy and minimize any possible complications. Investigation of optimal indications for IUI-hCG should be highlighted in the future.

Intrauterine administration of human chorionic gonadotropin improves the live birth rates of patients with repeated implantation failure in frozen-thawed blastocyst transfer cycles by increasing the percentage of peripheral regulatory T cells

INTRODUCTION

Repeated implantation failure (RIF) frustrates both patients and their clinicians. Our aim was to observe the effects of intrauterine administration of human chorionic gonadotropin (hCG) on pregnancy outcomes of patients who received frozen-thawed embryo transfer (FET).

METHODS

A prospective cohort study was conducted to evaluate the impact of intrauterine administration of hCG on pregnancy outcomes in FET cycles of patients with RIF from January 1st 2016 to December 31st 2016. The treatment group (n = 153, 152 cycles) received an infusion of 500 IU of hCG diluted in normal saline 3 days before embryo transfer. The control group (n = 152, 151 cycles) received embryo transfer with a previous intrauterine injection of normal saline without hCG. Early morning fasting blood samples were obtained from each patient for the measurement of peripheral regulatory T cells (Tregs) on the day of embryo transfer. The outcome parameters including Tregs in each group were compared.

RESULTS

The patients in the hCG-treated group had significantly higher clinical pregnancy rates, implantation rates and live birth rates than the controls (37.5% versus 25.17%, 29.19% versus 19.4%, 26.97% versus 17.22%, respectively). They also had significantly higher percentages of peripheral Tregs than the controls (6.1 ± 0.6% versus 5.4 ± 1.0%). In addition, the clinical pregnancy rate, implantation rate and live birth rate in patients who received blastocyst transfer were significantly higher in the hCG-treated group when compared to the control group (41.38% versus 26.44%, 42.22% versus 26.14%, 33.33% versus 17.24%, respectively). We also showed that the clinical pregnancy rate, implantation rate and live birth rate were significantly higher in hCG-treated group when compared to the control group (49.12% versus 28.07%, 49.15% versus 28.07%, 40.35% versus 17.54%, respectively) of RIF patients with blastocyst transfer under 35 years, while there was on difference in patients above 35 years.

CONCLUSIONS

Intrauterine administration of hCG significantly improves the clinical pregnancy rate, implantation rate and live birth rate in FET cycles of patients with RIF by increasing Tregs. The treatment improves the pregnancy outcomes much more for younger RIF patients transferred blastocysts.

Intrauterine administration of human chorionic gonadotropin (hCG) for subfertile women undergoing assisted reproduction

BACKGROUND

Most women undergoing assisted reproduction treatment will reach the stage of embryo transfer (ET), but the proportion of embryos that can be successfully implanted after ET has remained small since the mid-1990s. Human chorionic gonadotropin (hCG) is a hormone that is synthesised and released by the syncytiotrophoblast and has a fundamental role in embryo implantation and the early stages of pregnancy. Intrauterine administration of hCG via ET catheter during a mock procedure around the time of ET is a novel approach that has been suggested to improve the outcomes of assisted reproduction.

OBJECTIVES

To investigate whether intrauterine (intracavity) administration of hCG (IC-hCG) around the time of ET improves clinical outcomes in subfertile women undergoing assisted reproduction.

SEARCH METHODS

We performed searches on 9 January 2018 using Cochrane methods.

SELECTION CRITERIA

We looked for randomised controlled trials (RCTs) evaluating IC-hCG around the time of ET, irrespective of language and country of origin.

DATA COLLECTION AND ANALYSIS

Two review authors independently selected studies, assessed risk of bias, extracted data from studies, and attempted to contact study authors when data were missing. We performed statistical analysis using Review Manager 5. We assessed evidence quality using GRADE methods. Primary outcomes were live birth and miscarriage; secondary outcomes were clinical pregnancy rate and complications.

MAIN RESULTS

Seventeen RCTs investigated the effects of IC-hCG administration for 4751 subfertile women undergoing assisted reproduction. IC-hCG was administered in variable doses at different times before the ET. hCG was obtained from the urine of pregnant women or from cell cultures using recombinant DNA technology.Most studies (12/17) were at high risk of bias in at least one of the seven domains assessed. Common problems were unclear reporting of study methods and lack of blinding. The main limitations for evidence quality were high risk of bias and serious imprecision.For analyses of live birth and clinical pregnancy, there was considerable heterogeneity (I² > 75%) and therefore we present subgroups for dosage and stage of ET. Exploration for sources of heterogeneity revealed two key prespecified variables as important determinants: stage of ET (cleavage vs blastocyst stage) and dose of IC-hCG (< 500 international units (IU) vs ≥ 500 IU). We performed meta-analyses within subgroups defined by stage of embryo and dose of IC-hCG.Live birth rates among women having cleavage-stage ET with an IC-hCG dose < 500 IU compared to women having cleavage-stage ET without IC-hCG showed no benefit of the intervention and would be consistent with no substantive difference or disadvantage of indeterminate magnitude (risk ratio (RR) 0.76, 95% confidence interval (CI) 0.58 to 1.01; one RCT; 280 participants; I² = 0%; very low-quality evidence). In a clinic with a live birth rate of 49% per cycle, use of IC-hCG < 500 IU would be associated with a live birth rate ranging from 28% to 50%.Results show an increase in live birth rate in the subgroup of women undergoing cleavage-stage ET with an IC-hCG dose ≥ 500 IU compared to women having cleavage-stage ET without IC-hCG (RR 1.57, 95% CI 1.32 to 1.87; three RCTs; 914 participants; I² = 0%; moderate-quality evidence). At a clinic with a live birth rate of 27% per cycle, use of IC-hCG ≥ 500 IU would be associated with a live birth rate ranging from 36% to 51%.Results show no substantive differences in live birth among women having blastocyst-stage ET with an IC-hCG dose ≥ 500 IU compared to women having blastocyst-stage ET without IC-hCG (RR 0.92, 95% CI 0.80 to 1.04; two RCTs; 1666 participants; I² = 0%; moderate-quality evidence). At a clinic with a live birth rate of 36% per cycle, use of IC-hCG ≥ 500 IU would be associated with a live birth rate ranging from 29% to 38%.Evidence for clinical pregnancy among women having cleavage-stage ET with an IC-hCG dose < 500 IU showed no benefit of the intervention and would be consistent with no substantive difference or disadvantage of indeterminate magnitude (RR 0.88, 95% CI 0.70 to 1.10; one RCT; 280 participants; I² = 0%; very low-quality evidence).Results show an increase in clinical pregnancy rate in the subgroup of women having cleavage-stage ET with an IC-hCG dose ≥ 500 IU compared to women having cleavage-stage ET without IC-hCG (RR 1.49, 95% CI 1.32 to 1.68; 12 RCTs; 2186 participants; I² = 18%; moderate-quality evidence).Results show no substantive differences in clinical pregnancy among women having blastocyst-stage ET with an IC-hCG dose ≥ 500 IU (RR 0.99, 95% CI 0.85 to 1.15; four RCTs; 2091 participants; I² = 42%; moderate-quality evidence) compared to women having blastocyst-stage ET with no IC-hCG.No RCTs investigated blastocyst-stage ET with an IC-hCG dose < 500 IU.We are uncertain whether miscarriage was influenced by intrauterine hCG administration (RR 1.04, 95% CI 0.81 to 1.35; 11 RCTs; 3927 participants; I² = 0%; very low-quality evidence).Reported complications were ectopic pregnancy (four RCTs; 1073 participants; four events overall), heterotopic pregnancy (one RCT; 495 participants; one event), intrauterine death (three RCTs; 1078 participants; 22 events), and triplets (one RCT; 48 participants; three events). Events were few, and very low-quality evidence was insufficient to permit conclusions to be drawn.

AUTHORS' CONCLUSIONS

There is moderate quality evidence that women undergoing cleavage-stage transfer using an IC-hCG dose ≥ 500 IU have an improved live birth rate. There is insufficient evidence for IC-hCG treatment for blastocyst transfer. There should be further trials with live birth as the primary outcome to identify the groups of women who would benefit the most from this intervention. There was no evidence that miscarriage was reduced following IC-hCG administration, irrespective of embryo stage at transfer or dose of IC-hCG. Events were too few to allow conclusions to be drawn with regard to other complications.

Endogenous Interleukin-1β Is Implicated in Intraplaque Hemorrhage in Apolipoprotein E Gene Null Mice

BACKGROUND

Intraplaque hemorrhage (IPH) has been implicated in plaque instability and rupture in atherosclerotic lesions, although the mechanisms by which IPH progresses remain largely unknown. In this study, apolipoprotein E-deficient mice with carotid artery ligation and cuff placement around the artery were used, and pro-inflammatory cytokines that are implicated in IPH were analyzed.Methods and Results:The expression of interleukin-1β (IL-1β) increased significantly following cuff placement compared with mice with carotid artery ligation alone. IPH occurred in the cuff-placed carotid artery following treatment with the negative control (NC) small interfering RNA (siRNA). However, the occurrence was significantly reduced in the cuff-placed carotid artery following treatment with an IL-1β siRNA. Neovessel formation was significantly reduced in the carotid artery treated with the NC siRNA compared with that treated with IL-1β siRNA. IL-1β significantly inhibited the tube formation and wound healing capacities of vascular endothelial cells in vitro. Furthermore, immunostaining of matrix metalloproteinase-9 (MMP-9) significantly increased in the carotid artery treated with the NC siRNA compared with that treated with IL-1β siRNA.

CONCLUSIONS

These results suggest that endogenous IL-1β is implicated in the progression of IPH via the inhibition of physiological angiogenesis in the atherosclerotic plaque, leading to the formation of leaky neovessels. Furthermore, the stimulation of MMP-9 expression may also contribute to the formation of leaky neovessels.

Effects of intrauterine perfusion of human chorionic gonadotropin in women with different implantation failure numbers

PROBLEM

The aim of this research was to investigate the effects of the intrauterine perfusion of hCG before a frozen-thawed embryo transfer (FET) in women with different implantation failure numbers.

METHOD OF STUDY

This was a retrospective analysis of patients undergoing FET who received an intrauterine injection hCG 1000 IU before embryo transfer. The groups included women with their first implantation failure (A group, n = 26), second implantation failure (B group, n = 122), and three or more failures (C group, n = 77). Corresponding control groups (no infusion) were also included. The pregnancy rates were compared among these groups.

RESULTS

After intrauterine injection hCG, the biochemical pregnancy rates were 92.30%, 63.11%, 49.02%, and the clinical pregnancy rates were 76.92%, 54.91%, 48.05%, in the A, B, and C groups, respectively. The biochemical and clinical pregnancy rates were significantly higher in the A group than in the other groups (P < .05). The clinical pregnancy rates of the A and C groups were significantly higher than in the corresponding (no infusion) control groups (76.92% vs 56.81% and 48.05% vs 33.33%, P < .05).

CONCLUSION

Pregnancy rates decreased with the number of transplant failures. The intrauterine administration of hCG before FET significantly improved the pregnancy rates, especially after one and three or more implantation failures.

High oestradiol concentration after ovarian stimulation is associated with lower maternal serum beta-HCG concentration and neonatal birth weight

In this retrospective study, the relationship between maternal serum oestradiol and progesterone levels after fresh embryo transfer or frozen embryo transfer (FET), and serum beta-HCG levels in early pregnancy and neonatal birth weight was examined. Included for analysis were 5643 conceived singletons: 2610 after FET and 3033 after fresh embryo transfer. Outcome measures included maternal serum oestradiol, progesterone, beta-HCG levels during the peri-implantation period, birth weight and small-for-gestational-age (SGA). Results at 4, 5 and 6 weeks' gestation were as follows: serum oestradiol and progesterone levels were significantly higher in women who underwent fresh embryo transfer compared with FET (all P < 0.0001 except progesterone at 6 weeks; P = 0.009); for fresh embryo transfers, serum beta-HCG levels were significantly lower than in women who underwent FET (P < 0.0001); beta-HCG levels were negatively correlated with serum oestradiol; and birth weight was negatively correlated with serum oestradiol. Incidence of SGA in fresh embryo transfer was increased significantly compared with FET (P < 0.001). Higher maternal oestradiol levels after fresh embryo transfer was correlated with lower beta-HCG in early pregnancy, lower birth weight and higher incidence of SGA.

Effect of intrauterine injection of human chorionic gonadotropin before embryo transfer on pregnancy rate: A prospective randomized study

BACKGROUND

Human chorionic gonadotropin (hCG) as the most important factor to controlled implantation is one of the early embryonic signals in primates that is secreted by the embryo before its implantation. This study was designed to assess the effects of intrauterine injection of hCG before the embryo transfer in an in vitro fertilization (IVF) or intracytoplasmic sperm injection (ICSI) cycle on pregnancy rate in infertile patients.

MATERIALS AND METHODS

This randomized study was done on 100 infertile patients in two groups: intervention group received injection of 700 IU of intrauterine hCG 10 min before embryo transfer and control group did not receive hCG. The pregnancy rate was tested 2 weeks after embryo transfer, and if the pregnancy test was positive, a transvaginal ultrasound was performed 3 weeks later to search for signs of pregnancy, such as the presence of a gestational sac, embryo, and fetal heart rate, and confirmed as successful pregnancy.

RESULTS

Pregnancy test was positive in 13 (28.6%) of 46 patients in hCG group and in control group was positive in 6 (12.5%) of 48 patients. The pregnancy rate between hCG group and control group was not significantly different (P = 0.54). The pregnancy rate in hCG group with IVF fertilization was 20.8% and in their controls was 7.4% (P = 0.51). The pregnancy rate in hCG group with ICSI fertilization was 36.4% and in their controls was 19% (P = 0.16).

CONCLUSION

The intrauterine injection of 700 IU of hCG before embryo transfer improved pregnancy rate compared to control group but was not significantly different.

Intrauterine administration of hCG immediately after oocyte retrieval and the outcome of ICSI: a randomized controlled trial

STUDY QUESTION

Does the intrauterine administration of hCG immediately after oocyte retrieval in antagonist cycles with ICSI and fresh embryo transfer (ET) influence the implantation rate or chemical and clinical pregnancy rates?

SUMMARY ANSWER

The intrauterine administration of hCG after oocyte retrieval increases the implantation rate and chemical and clinical pregnancy rates.

WHAT IS KNOWN ALREADY

Over half of IVF/ICSI cycles fail due to implantation failure. Intrauterine administration of hCG, a few minutes before ET, increased the implantation and pregnancy rates in most but not in all studies. The effect of intrauterine administration of hCG, after oocyte retrieval, has not yet been studied.

STUDY DESIGN, SIZE, DURATION

The study was a parallel, triple-blind randomized clinical trial (RCT) performed from September 2015 to February 2016, in a university hospital. We recruited women undergoing antagonist ovarian stimulation, ICSI and ET. For an effect size of 0.2, power of 80% at a significance level of 0.05, we needed 150 participants. Accounting for a 7% dropout rate, a total of 160 women was considered appropriate. A computer-generated randomization list with a block size of 4, with 1:1 allocation was used. The treatment allocation was placed in a sealed, opaque, envelope and picked up consecutively. Immediately after oocyte retrieval, patients in the intervention and control groups were treated with intrauterine injection of hCG and saline, respectively. Participants underwent ET on Day 3. A beta-hCG test was done at 2 weeks. If positive, three transvaginal-ultrasonographies (TVSs) were done at 3, 4 and 10 weeks after ET. The participants were called up thereafter and questioned about the continuity of their pregnancy.

PARTICIPANTS/MATERIALS, SETTING, METHOD

Of 1990 women attending the infertility clinic of our university hospital, 508 were IVF/ICSI candidates during the study period, and 245 of the patients on an antagonist cycle met the criteria to be invited into our trial. Inclusion criteria were normal ovarian reserve, age ≤41, undergoing ICSI, and fresh ET and normal TSH and prolactin. Uncontrolled chronic disease, severe hydrosalpinx, severe endometriosis, morphologic embryo deficiencies, non-obstructive azospermia and high risk of severe ovarian hyperstimulation syndrome were criteria for exclusion. After taking an informed consent, a total of 158 participants were recruited, of which 80 were randomly allocated to receive intrauterine 500 IU hCG in up to 0.5 ml normal saline and 78 to receive intrauterine 0.5 ml normal saline immediately after oocyte retrieval, during general anaesthesia. ICSI was performed conventionally. The 4-8 cell embryos were transferred on the third day after oocyte retrieval. Implantation rate, chemical and clinical pregnancy rates were analysed and compared between the two groups.

MAIN RESULTS AND THE ROLE OF CHANCE

Patients' demographic and baseline characteristics were comparable. The clinical results showed statistically significant differences between the two groups regarding the biochemical pregnancy rate (59.2 versus 31.3%; P = 0.001; odds ratio (OR) = 1.88; 95% CI, 1.26-2.82; risk difference (RD) = 27.8; 95% CI, 11.2-42.3), implantation rate (37 versus 17%; P = 0.012; OR = 2.29; 95% CI, 1.02-5.14; RD = 20.2; 95% CI, 5.4-33.8), clinical pregnancy rate (50.7 versus 16.4%; P < 0.001; OR = 3.08; 95% CI, 1.71-5.55; RD = 34.3; 95% CI, 18.7-47.6) and ongoing pregnancy rate (40.1 versus 13.4%; P = 0.001; OR = 3.04; 95% CI, 1.55-5.93; RD = 27.4; 95% CI, 12.7-40.6). The abortion and ectopic pregnancy rates were not statistically different between the two groups.

LIMITATIONS, REASONS FOR CAUTION

The insertion of an intrauterine insemination catheter and the injection of a small amount of saline into the uterine cavity (without hCG) may also have some impact on implantation. This effect could be studied by comparing this intervention with another study group without any intrauterine injection.There are no specific side effects mentioned in the literature for the intrauterine administration of hCG, neither were any observed in our study, but it is best to be cautious about probable side effects, because this type of intervention is relatively new and experimental, and deserves more studies before being entered into routine clinical practice.

WIDER IMPLICATIONS OF THE FINDINGS

Intrauterine administration of hCG immediately after oocyte pick up increases its effectiveness; however, further investigations are required before this procedure can be recommended for clinical practice.

STUDY FUNDING/COMPETING INTERESTS

This study was supported by the Women's Health Research Center, Tabriz University of Medical Sciences, Iran. No external funds were used. The authors have no conflicts of interest to declare.

TRIAL REGISTRATION NUMBER

IRCT201206165485N4.

TRIAL REGISTRATION DATE

2 September 2015.

DATE OF FIRST PATIENT'S ENROLMENT

2 September 2015.

Intrauterine administration of human chorionic gonadotropin (hCG) for subfertile women undergoing assisted reproduction

BACKGROUND

Subfertility affects 15% of couples and represents the inability to conceive naturally following 12 months of regular unprotected sexual intercourse. Assisted reproduction refers to procedures involving the in vitro handling of both human gametes and represents a key option for many subfertile couples. Most women undergoing assisted reproduction treatment will reach the stage of embryo transfer (ET) but the proportion of embryos that successfully implant following ET has remained small since the mid-1990s. Human chorionic gonadotropin (hCG) is a hormone synthesised and released by the syncytiotrophoblast and has a fundamental role in embryo implantation and the early stages of pregnancy. Intrauterine administration of synthetic or natural hCG via an ET catheter during a mock procedure around the time of ET is a novel approach that has recently been suggested to improve the outcomes of assisted reproduction.

OBJECTIVES

To investigate whether the intrauterine administration of hCG around the time of ET improves the clinical outcomes in subfertile women undergoing assisted reproduction.

SEARCH METHODS

We performed a comprehensive literature search of the Cochrane Gynaecology and Fertility Group Specialised Register, Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, EMBASE, CINAHL, PsycINFO, registers of ongoing trials andreference lists of all included studies and relevant reviews (from inception to 10 November 2015), in consultation with the Cochrane Gynaecology and Fertility Group Trials Search Co-ordinator.

SELECTION CRITERIA

We included all randomised controlled trials (RCTs) evaluating intrauterine administration of hCG around the time of ET in this review irrespective of language and country of origin.

DATA COLLECTION AND ANALYSIS

Two authors independently selected studies, assessed risk of bias, extracted data from studies and attempted to contact the authors where data were missing. We performed statistical analysis using Review Manager 5 in accordance with the Cochrane Handbook for Systematic Reviews of Interventions. We assessed evidence quality using GRADE methods.

MAIN RESULTS

Twelve RCTs investigated the effect of intrauterine administration of hCG for 4038 subfertile women undergoing assisted reproduction. The intra-cavity hCG (IC-hCG) was administered in variable doses at different timings before the ET. The source of hCG was from the urine of pregnant women or from cell cultures using recombinant DNA technology.Most of the studies (9/12) were at high risk of bias in at least one of the seven domains assessed. Common problems were unclear reporting of study methods and lack of blinding. The main limitations in the overall quality of the evidence were high risk of bias and serious imprecision.For the analyses of live birth and clinical pregnancy, there was considerable heterogeneity (I(2) greater than 75%) and we did not undertake a meta-analysis. Exploration for the sources of heterogeneity identified two key pre-specified variables as important determinants: stage of ET (cleavage versus blastocyst stage) and dose of IC-hCG (less than 500 international units (IU) versus 500 IU or greater). We then performed meta-analysis for these analyses within the subgroups defined by stage of embryo and dose of IC-hCG.There was an increase in live birth rate in the subgroup of women having cleavage-stage ETs with an IC-hCG dose of 500 IU or greater compared to women having cleavage-stage ETs with no IC-hCG (risk ratio (RR) 1.57, 95% confidence interval (CI) 1.32 to 1.87, three RCTs, n = 914, I(2) = 0%, moderate quality evidence). In a clinic with a live birth rate of 25% per cycle then the use of IC-hCG -500 IU or greater would be associated with a live birth rate that varies from 33% to 46%. We did not observe a significant effect on live birth in any of the other subgroups.The was an increase in clinical pregnancy rate in the subgroup of women having cleavage-stage ETs with an IC-hCG dose of 500 IU or greater compared to women having cleavage-stage ETs with no IC-hCG (RR 1.41, 95% CI 1.25 to 1.58, seven RCTs, n = 1414, I(2) = 0%, moderate quality evidence). We did not observe a significant effect on clinical pregnancy in either of the other subgroups.There was no evidence that miscarriage was influenced by intrauterine hCG administration (RR 1.09, 95% CI 0.83 to 1.43, seven RCTs, n = 3395, I(2) = 0%, very low quality evidence).Other complications reported in the included studies were ectopic pregnancy (three RCTs, n = 915, three events overall), heterotopic pregnancy (one RCT, n = 495, one event), intrauterine death (two RCTs, n = 978, 21 events) and triplets (one RCT, n = 48, three events). There was no evidence of a difference between the groups, but there were too few events to allow any conclusions to be drawn and the evidence was very low quality.

AUTHORS' CONCLUSIONS

The pregnancy outcome for cleavage-stage ETs using an IC-hCG dose of 500 IU or greater is promising. However, given the small size and the variable quality of the trials and the fact that the positive finding was from a subgroup analysis, the current evidence for IC-hCG treatment does not support its use in assisted reproduction cycles. A definitive large clinical trial with live birth as the primary outcome is recommended. There was no evidence that miscarriage was influenced by intrauterine hCG administration, irrespective of embryo stage at transfer or dose of IC-hCG. There were too few events to allow any conclusions to be drawn with regard to other complications.

Therapeutic Potential of Human Chorionic Gonadotropin Against Painful Bladder Syndrome/Interstitial Cystitis

Painful bladder syndrome/interstitial cystitis is a debilitating chronic bladder disease that primarily affects women. The disease is due to a damage of urothelial cell lining. As a result, potassium particles and other toxic substances in urine can leak into bladder mucosa, causing the symptoms of lower abdominal/pelvic discomfort, pain, increased urination frequency, urgency, nocturia, and so on, all of which can substantially reduce the quality of daily life. There are multiple symptom reliving therapies. Among them, only pentosan polysulfate sodium, sold under the brand name of Elmiron, has been approved for oral use by US Food and Drug Administration. It provides the relief after several months of use. Based on the scientific leads presented in this article, we propose that human chorionic gonadotropin has a therapeutic potential that is worth investigating for the treatment of this disease.

Impact of TNF and IL-1β on capillary networks within engineered human adipose tissues

Inflammatory cytokines lead to capillary network disorganization and secreted factor modulation within human microvascularized engineered adipose tissues.

Regulation of inflammatory and angiogenesis mediators in a functional model of decidualized endometrial stromal cells

The mechanisms involving the expression of interleukin (IL) 1 family members in the process of preparing the endometrium to receive an embryo remain unclear. In this study, decidualization differentially skewed the balance of IL1 family receptor expression in a pattern that increases endometrial stromal cell receptivity to IL1, IL18 and IL33. Additionally, endometrial cells showed increased expression of homeobox HOXA10 and HOXA11 and LIFR, which are known to be involved in endometrial embryo receptivity. Further analyses of decidual endometrial cells revealed a significant increase in the release of potent proinflammatory, remodelling and angiogenic factors implicated in the embryo invasion process, such as VEGF (P = 0.0305), MMP9 (P = 0.0003), TIMP3 (P = 0.0001), RANTES (P = 0.0020), MCP1 (P = 0.0001) and MIF (P = 0.0068). No significant changes in endogenous IL1B secretion were observed. Decreased secretion of IL18 and decidualization increased secretion of IL33. These findings reveal a significant modulation of endometrial cell receptivity to IL1 family members during endometrial stromal cell decidualization, and suggest that the involvement of IL1 family members is important in physiological processes of endometrial receptivity, including adaptive immunology. This may be relevant to establishing a favourable uterine microenvironment for embryo implantation.

The efficacy of intrauterine injection of human chorionic gonadotropin before embryo transfer in assisted reproductive cycles: Meta-analysis

OBJECTIVES

A systematic review and meta-analysis to evaluate the effect of human chorionic gonadotropin (hCG) intrauterine injection before embryo transfer on the outcome of in vitro fertilization (IVF) and intracytoplasmic sperm injection (ICSI).

METHODS

Searches of PubMed®, EMBASE®, EBSCO, Web of Science®, SCOPUS® and Cochrane Central Register of Controlled Trials were conducted to retrieve relevant randomized controlled trials (RCTs). Data were extracted and analysed.

RESULTS

The meta-analysis included five RCTs (hCG group n = 680; control group n = 707). Intrauterine hCG injection significantly increased rates of biochemical, clinical and ongoing pregnancy compared with controls. There were no between-group differences in implantation or miscarriage rates.

CONCLUSION

Women undergoing IVF/ICSI may benefit from intrauterine hCG injection before embryo transfer.

Pregnancy and the Immune System: General Overview and the Gastroenterological Perspective

Pregnancy represents a unique immune tolerant condition that cannot be attributed merely to generalized immunosuppression. A variety of mechanisms have been described, ranging from the non-self recognition, immunomodulation of specific inflammatory cell populations and a Th2-directed shift of the immune response, which are mediated by both localized and systemic mediators. Furthermore, an inflammatory response directed toward the conceptus is no longer considered an obligatory deleterious response; instead, it is considered an important factor that is necessary for normal growth and development. These immunomodulatory changes during pregnancy may also affect concurrent conditions and alter the course of inflammatory diseases. Herein, we review the main immunomodulatory changes that occur during pregnancy and their effect on coexisting inflammatory conditions, with a specific focus on gastrointestinal disorders.

Bisphenol A modulates receptivity and secretory function of human decidual cells: an in vitro study

The human endometrium is a fertility-determining tissue and a target of steroid hormones' action. Endocrine disruptors (EDs) can exert adverse effects on the physiological function of the decidua at the maternal-fetal interface. We examined the potential effects of an ED, bisphenol A (BPA), on endometrial maturation/decidualization, receptivity, and secretion of decidual factors (biomarkers). In vitro decidualized, endometrial stromal cells from six hysterectomy specimens were treated with 1  pM-1  μM of BPA, for 24  h and assessed for cell viability and proliferation. Three non-toxic concentrations of BPA (1  μM, 1  nM, and 1  pM) were selected to study its influence on secretion of cell decidualization biomarkers (IGF-binding protein and decidual prolactin (dPRL)), macrophage migration inhibitory factor (MIF) secretion, and hormone receptors' expression (estrogen receptors (ERα and ERβ); progesterone receptors (PRA and PRB); and human chorionic gonadotropin (hCG)/LH receptor (LH-R)). The results showed a decrease in cell viability (P<0.001) in response to BPA at the level of 1  mM. At the non-toxic concentrations used, BPA perturbed the expression of ERα, ERβ, PRA, PRB, and hCG/LH-R (P<0.05). Furthermore, 1  μM of BPA reduced the mRNA transcription of dPRL (P<0.05). Secretion of MIF was stimulated by all BPA treatments, the lowest concentration (1  pM) being the most effective (P<0.001). The multi-targeted disruption of BPA on decidual cells, at concentrations commonly detected in the human population, raises great concern about the possible consequences of exposure to BPA on the function of decidua and thus its potential deleterious effect on pregnancy.

hCG stimulates angiogenic signals in lymphatic endothelial and circulating angiogenic cells

Human chorionic gonadotropin (hCG) has long been associated with the initiation and maintenance of pregnancy, where angiogenesis plays an important role. However, the function of hCG in angiogenesis and the recruitment of vascular active cells are not fully understood. In this study, the role of hCG and its receptor in circulating angiogenic and human endothelial cells, including lymphatic, uterine microvascular, and umbilical vein endothelial cells, was examined. Immunohistochemistry and immunoblot analysis were used to detect LH/hCG receptor expression and the expression of hCG-induced angiogenic molecules. HIF-1α was determined via ELISA and downstream molecules, such as CXCL12 and CXCR4, via real-time PCR. Chemotaxis was analyzed using Boyden chambers. Our results show that the LH/hCG receptor was present in all tested cells. Furthermore, hCG was able to stimulate LH/hCG-receptor-specific migration in a dose-dependent fashion and induce key angiogenic molecules, including HIF-1α, CXCL12, and CXCR4. In conclusion, our findings underscore the importance of hCG as one of the first angiogenic molecules produced by the conceptus. hCG itself alters endothelial motility, recruitment, and expression of pro-angiogenic molecules and may therefore play an important role in vascular adaption during implantation and early placental formation.

Inhibitory effect of insulin-like growth factor-binding protein-7 (IGFBP7) on in vitro angiogenesis of vascular endothelial cells in the rat corpus luteum

Angiogenesis in the developing corpus luteum (CL) is a prerequisite for establishment and maintenance of an early pregnancy. To explore the physiological significance of insulin-like growth factor-binding protein-7 (IGFBP7) in the developing CL, the effects of IGFBP7 on vascular endothelial growth factor (VEGFA)- and luteinizing hormone (LH)-induced in vitro tube formation were tested using isolated luteal microvascular endothelial cells (LECs). Capillary-like tube formation of LECs and their proliferation were stimulated by both VEGFA and LH. IGFBP7 treatment suppressed VEGFA- or LH-induced tube formation. The proliferation and migration of LECs, and phosphorylation of mitogen-activated protein kinase kinase and extracellular signal-regulated kinase 1/2 were inhibited by IGFBP7. Furthermore, IGFBP7 attenuated VEGFA-enhanced cyclooxygenase (COX)-2 mRNA expression and prostaglandin E₂ secretion. These findings suggest the possibility that luteal IGFBP7 secretion may suppress the stimulatory effect of VEGFA on angiogenesis in the early CL.

Effect of intrauterine injection of human chorionic gonadotropin before embryo transfer on clinical pregnancy rates from in vitro fertilisation cycles: a prospective study

BACKGROUND

The implantation process after embryo transfer depends on the embryo quality and endometrial receptivity. It is estimated that fifty to seventy-five per cent of pregnancies are lost due to a failure of implantation. There is evidence that there is an early secretion of human chorionic gonadotrophin before embryo implantation, and this secretion has been linked to an important function in angiogenesis and the inflammatory response that promotes the implantation process. Our objective was to determine the effects of intrauterine injection of human chorionic gonadotropin (hCG) before the embryo transfer in an in vitro fertilisation cycle.

METHODS

A prospective randomised study was conducted in Reproductive Medicine Centre PROCREA in Mexico City. Infertile patients who had a medical indication for in vitro fertilisation were studied. Two groups were included (n 210); the intervention group received an intrauterine injection of 500 IU of hCG before the embryo transfer (n 101). The control group (n 109) did not receive hCG. Comparisons were performed using a chi-square test.

RESULTS

The clinical pregnancy rate (CPR) was our principal outcome. The implantation rate was a secondary outcome. The implantation rate was significantly higher in the hCG group compared to the control group (52.4% vs 35.7%, p 0.014). The clinical pregnancy rate was also significantly higher (50.4 vs 33.0%, p 0.010). No adverse effects were observed.

CONCLUSIONS

The intrauterine injection of hCG before embryo transfer showed a significant increase in the clinical pregnancy rate. More clinical trials are needed to reproduce these results on this promising intervention. The live birth rate must be included in subsequent studies.

The Endocrine Milieu and CD4 T-Lymphocyte Polarization during Pregnancy

Acceptance of the fetal semi-allograft by the mother's immune system has become the focus of intensive research. CD4+ T cells are important actors in the establishment of pregnancy. Th1/Th2 paradigm has been expanded to include CD4+ regulatory T (Treg) and T helper 17 (Th17) cells. Pregnancy hormones exert very significant modulatory properties on the maternal immune system. In this review, we describe mechanisms by which the endocrine milieu modulates CD4 T cell polarization during pregnancy. We first focused on Treg and Th17 cells and on their importance for pregnancy. Secondly, we review the effects of pregnancy hormones [progesterone (P4) and estradiol (E2)] on immune cells previously described, with a particular attention to human chorionic gonadotropin (hCG). The importance of Treg cells for pregnancy is evidenced. They are recruited before implantation and are essential for pregnancy maintenance. Decreased number or less efficient Treg cells are implicated in fertility disorders. As for Th17 cells, the few available studies suggest that they have a negative impact on fertility. Th17 frequency is increased in infertile patients. With the combination of its pro-effects on Th2 and Treg cells and anti-effects on Th1 and Th17 cells, P4 contributes to establishment of a favorable environment for pregnancy. E2 effects are more dependent on the context but it seems that E2 promotes Treg and Th2 cells while it inhibits Th1 cells. hCG positively influences activities of Treg and uterine natural killer cells. This embryo signal is an essential actor for the success of pregnancy, both as the endocrine factor regulating P4 secretion by the ovarian corpus luteum, but also as a paracrine agent during implantation as well as an angiogenic and immunologic mediator during the course of gestation. Luteinizing hormone (LH) immune properties begin to be studied but its positive impact on Treg cells suggests that LH could be a considerable immunomodulator in the mouse.