Role of the endometrial tripod interleukin-18, -15, and -12 in inadequate uterine receptivity in patients with a history of repeated in vitro fertilization–embryo transfer failure

Decidualized human endometrial stromal cells are sensors of hormone withdrawal in the menstrual inflammatory cascade

Menstruation is a complex process dependent on premenstrual release of inflammatory mediators and proteolytic enzymes from endometrial cells. Endometrial leukocytes are traditionally considered to be the major source of the inflammatory factors. However, evidence is emerging to suggest a role for decidualized endometrial stromal cells in the premenstrual inflammatory cascade. We sought to determine if withdrawal of hormone support (estrogen and progesterone) from decidualized endometrial stromal cells, in a model mimicking the precise timing leading to menstruation, activated inflammatory signaling pathways and downstream release of inflammatory mediators. Human endometrial stromal cells decidualized gradually over 12 days of estradiol and progestin treatment as evidenced by an increase in prolactin secretion. Withdrawal of hormone support from decidualized stromal cells resulted in a decrease in cytoplasmic IkappaB and a progressive increase in nuclear accumulation of NF-kappaB, as demonstrated by Western immunoblot and immunocytochemical analyses. Concomitant with nuclear translocation of NF-kappaB, hormone withdrawal led to production of a host of inflammatory mediators by the decidualized stromal cells, including IFN-alpha, IL-6, CCL11, GM-CSF, CCL2, IL1-RA, CXCL10, CXCL8, IL-12, IL-15, VEGF, and CCL5. Elevation of inflammatory mediators was not observed, however, upon hormone withdrawal in cells treated with the NF-kappaB inhibitor BAY 11-7085. Decidualized stromal cells are likely highly sensitive sensors of changing hormone levels. This provides a mechanism by which decidualized stromal cells may recruit inflammatory leukocytes into the premenstrual endometrium and contribute to the intense inflammation underlying this unique physiological process.

Inflammation, NK cells and implantation: friend and foe (the good, the bad and the ugly?): replacing placental viviparity in an evolutionary perspective

This review summarises an invited talk presented at the 2012 ESRI/ASRI meeting in Hamburg, concerning current views of inflammation in pregnancy, which is timely given that the effects of a local injury in the uterus acts to favour implantation. Recalling that inflammation can be good (it is useful and necessary for implantation), bad (in implantation failure, RSA) and ugly (at the extreme, endometriosis is associated with pain and infertility) leads to consideration of its status in pregnancy. Its role in implantation and the fact that pregnancy maintains some aspects of inflammation throughout, leads to revision of not only concepts of immunosuppression and the Th1/Th2 paradigm, but also the feto-maternal relationship as seen since Medawar's hypotheses were advanced. This is examined from an evolutionary perspective, which should lead to further review of our perception of uterine NK cells, and the emergence of Treg cells to control some aspects of adaptive immunity, which appeared long after placentation.

Endometrial gene expression in the early luteal phase is impacted by mode of triggering final oocyte maturation in recFSH stimulated and GnRH antagonist co-treated IVF cycles

STUDY QUESTION

Do differences in endometrial gene expression exist after ovarian stimulation with four different regimens of triggering final oocyte maturation and luteal phase support in the same patient?

SUMMARY ANSWER

Significant differences in the expression of genes involved in receptivity and early implantation were seen between the four protocols.

WHAT IS KNOWN ALREADY

GnRH agonist triggering is an alternative to hCG triggering in GnRH antagonist co-treated cycles, resulting in an elimination of early ovarian hyperstimulation syndrome. Whereas previous studies have revealed a low ongoing clinical pregnancy rate after GnRH agonist trigger due to a high early pregnancy loss rate, despite supplementation with the standard luteal phase support, more recent studies, employing a 'modified' luteal phase support including a bolus of 1500 IU hCG on the day of oocyte aspiration, have reported ongoing pregnancy rates similar to those seen after hCG triggering.

STUDY DESIGN, SIZE DURATION

A prospective randomized study was performed in four oocyte donors recruited from an oocyte donation program during the period 2010-2011.

PARTICIPANTS, MATERIALS, SETTING, METHODS

Four oocyte donors in a university IVF center each prospectively underwent four consecutive stimulation protocols, with different modes of triggering final oocyte maturation and a different luteal phase support, followed by endometrial biopsy on Day 5 after oocyte retrieval. The following protocols were used: (A) 10 000 IU hCG and standard luteal phase support, (B) GnRH agonist (triptorelin 0.2 mg), followed by 1500 IU hCG 35 h after triggering final oocyte maturation, and standard luteal phase support, (C) GnRH agonist (triptorelin 0.2 mg) and standard luteal phase support and (D) GnRH agonist (triptorelin 0.2 mg) without luteal phase support. Microarray data analysis was performed with GeneSpring GX 11.5 (RMA algorithm). Pathway and network analysis was performed with the gene ontology software Ingenuity Pathways Analysis (Ingenuity® Systems, www.ingenuity.com, Redwood City, CA, USA). Samples were grouped and background intensity values were removed (cutoff at the lowest 20th percentile). A one-way ANOVA test (P< 0.05) was performed with Benjamini-Hochberg multiple testing correction.

MAIN RESULTS

Significant differences were seen in endometrial gene expression, related to the type of ovulation trigger and luteal phase support. However, the endometrial gene expression after the GnRH agonist trigger and a modified luteal phase support (B) was similar to the pattern seen after the hCG trigger (A).

LIMITATIONS, REASONS FOR CAUTION

The study was performed in four oocyte donors only; however, it is a strength of the study that the same donor underwent four consecutive stimulation protocols within 1 year to avoid inter-individual variations.

WIDER IMPLICATIONS OF THE FINDINGS

These endometrial gene-expression findings support the clinical reports of a non-significant difference in live birth rates between the GnRH agonist trigger and the hCG trigger, when the GnRH agonist trigger is followed by a bolus of 1500 IU hCG at 35 h post trigger in addition to the standard luteal phase support.

STUDY FUNDING/ COMPETING INTERESTS

This study was supported by an un-restricted research grant by MSD Belgium.

TRIAL REGISTRATION NUMBER

EudraCT number 2009-009429-26, protocol number 997 (P06034).

The correlation of autoantibodies and uNK cells in women with reproductive failure

There is conflicting evidence on the role of autoimmune disorders in reproductive failure, including recurrent miscarriage (RM) and recurrent implantation failure (RIF), after in vitro fertilisation (IVF). Several commonly studied autoimmune markers in women with reproductive failure include antiphospholipid antibodies (APAs), thyroid peroxidase antibodies (TPA) and uterine natural killer (uNK) cells. However, there have not been any studies that have examined the correlation of these markers in women with reproductive failure. To determine if women who tested positive for autoantibodies (APA and thyroid peroxidase antibodies) have significantly higher uNK cell numbers than women who tested negative for these antibodies, the percentage of stromal cells that stained positive for CD56 was identified by immunocytochemistry in endometrial biopsies from 42 women with unexplained RM (29 women tested negative for autoantibodies and 13 women tested positive for autoantibodies) and 40 women with unexplained RIF (30 women tested negative for autoantibodies and 10 women tested positive for autoantibodies). Biopsies were obtained on days LH+7 to LH+9. There was no significant difference in uNK cell numbers between women with unexplained RM who tested negative and those who tested positive for autoantibodies. Similarly, there was no significant difference in uNK cell numbers between women with unexplained RIF who tested negative and those who tested positive for autoantibodies. In women with reproductive failure the presence of autoantibodies does not appear to affect the numbers of uNK cells in the endometrium around the time of implantation.

Peri-implantation glucocorticoid administration for assisted reproductive technology cycles

BACKGROUND

In order to improve embryo implantation for in vitro fertilisation (IVF) or intracytoplasmic sperm injection (ICSI) cycles the use of glucocorticoids has been advocated. It has been proposed that glucocorticoids may improve the intrauterine environment by acting as immunomodulators to reduce the uterine natural killer (NK) cell count and normalise the cytokine expression profile in the endometrium and by suppression of endometrial inflammation.

OBJECTIVES

To investigate whether the administration of glucocorticoids around the time of implantation improved clinical outcomes in subfertile women undergoing IVF or ICSI when compared to no glucocorticoid administration.

SEARCH METHODS

The Cochrane Menstrual Disorders and Subfertility Group Trials Register (September 2011), the Cochrane Central Register of Controlled Trials (CENTRAL) (September 2011), MEDLINE (1966 to September 2011), EMBASE (1976 to September 2011), CINAHL (1982 to September 2011) and Science Direct (1966 to September 2011) were searched. Reference lists of relevant articles and relevant conference proceedings were handsearched.

SELECTION CRITERIA

All randomised controlled trials (RCTs) addressing the research question were included.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed eligibility and quality of trials and extracted relevant data.

MAIN RESULTS

Fourteen studies (involving 1879 couples) were included. Three studies reported live birth rate and these did not identify a significant difference after pooling the (preliminary) results (OR 1.21, 95% CI 0.67 to 2.19). With regard to pregnancy rates, there was also no evidence that glucocorticoids improved clinical outcome (13 RCTs; OR 1.16, 95% CI 0.94 to 1.44). However, a subgroup analysis of 650 women undergoing IVF (6 RCTs) revealed a significantly higher pregnancy rate for women using glucocorticoids (OR 1.50, 95% CI 1.05 to 2.13). There were no significant differences in adverse events, but these were poorly and inconsistently reported.

AUTHORS' CONCLUSIONS

Overall, there was no clear evidence that administration of peri-implantation glucocorticoids in ART cycles significantly improved the clinical outcome. The use of glucocorticoids in a subgroup of women undergoing IVF (rather than ICSI) was associated with an improvement in pregnancy rates of borderline statistical significance and should be interpreted with care. These findings were limited to the routine use of glucocorticoids and cannot be extrapolated to women with autoantibodies, unexplained infertility or recurrent implantation failure. Further well designed randomised studies are required to elucidate the possible role of this therapy in well defined patient groups.

Stimulation of the endometrium with high-grade blastocyst culture supernatant (SEHB) can improve pregnancy outcome for couples undergoing intracytoplasmic sperm injection (ICSI): a randomized clinical trial

PURPOSE

To evaluate the impact of stimulating the endometrium with high-grade blastocyst culture supernatant (SEHB) perfusion before blastocyst transfer (BT) on implantation rate, pregnancy rate, and pregnancy outcome in ICSI cycles.

MATERIALS AND METHODS

Ninety-four infertile couples who were referred to the Valiasr department of Imam Hospital complex between January 2010 and March 2011 enrolled in this randomized clinical trial. They were randomly divided into only BT or SEHB groups. Implantation rates, pregnancy rates, abortion, preterm and term delivery rates were compared between the two groups.

RESULTS

Implantation rates and pregnancy rates did not differ significantly between the two groups. The abortion rate was significantly higher in the BT only group while term delivery was significantly higher in SEHB group. Odds ratios of term delivery and abortion were 4.5 (p = 0.001) and 0.3 (p = 0.04), respectively.

CONCLUSION

The SEHB application may improve pregnancy outcome in infertile couples who are candidates for the ICSI reproductive method.

Commitment of decidual haematopoietic progenitor cells in first trimester pregnancy

PROBLEM  The aim of this study was to investigate the phenotype and commitment of decidual haematopoietic progenitor cells (HPCs) in healthy pregnant women and in women with early miscarriage. METHOD OF STUDY  Peripheral blood and decidual tissue from healthy and pathological pregnant women were examined for HPCs and lymphoid progenitors using flow cytometric analysis. RESULTS  Compared with peripheral blood, we found a significant increase in decidual HPCs in both healthy pregnant women and women with spontaneous abortion. T/NK, natural killer (NK), gamma-delta and NKT cell progenitors were identified in all peripheral blood and decidual samples. In pathologic pregnant women, the ratios of decidual T/NK and NK cell progenitors were significantly increased compared with healthy pregnant controls. CONCLUSION  We demonstrated decidual cells with haematopoietic progenitor cell phenotype in human decidua. Increased levels of NK progenitors in the decidua of women with early spontaneous abortion suggest a dysregulation of this pathway that may contribute to pregnancy failure.

Recent advances in understanding immunology of reproductive failure

Aspects of the immunological relationship between mother and conceptus still remain a mystery, although the recent advances in molecular biology have enlightened some of the parameters that participate in fetomaternal cross-talk during implantation. The atypical expression of major histocompatibility complex (MHC), the specific role of some hormones and cytokines, as well as the temporal and spatial distributions of uterine natural killer cells, represent substantive parameters of fetomaternal immunotolerance during implantation. Although human maternal and fetal immunology is difficult to investigate, aberrant immune responses and an imbalanced cytokine network may be related to infertility, implantation failures after IVF and recurrent pregnancy losses. In this review, immunological and interacting factors involved in human reproductive failure are summarized and critically evaluated.

TWEAK appears as a modulator of endometrial IL-18 related cytotoxic activity of uterine natural killers

Background

TWEAK (Tumor necrosis factor like WEAK inducer of apoptosis) is highly expressed by different immune cells and triggers multiple cellular responses, including control of angiogenesis. Our objective was to investigate its role in the human endometrium during the implantation window, using an ex-vivo endometrial microhistoculture model. Indeed, previous results suggested that basic TWEAK expression influences the IL-18 related uNK recruitment and local cytotoxicity.

Methodology/Principal Findings

Endometrial biopsies were performed 7 to 9 days after the ovulation surge of women in monitored natural cycles. Biopsies were cut in micro-pieces and cultured on collagen sponge with appropriate medium. Morphology, functionality and cell death were analysed at different time of the culture. We used this ex vivo model to study mRNA expressions of NKp46 (a uNK cytotoxic receptor) and TGF-beta1 (protein which regulates uNK cytokine production) after adjunction of excess of recombinant IL-18 and either recombinant TWEAK or its antibody. NKp46 protein expression was also detailed by immunohistochemistry in selected patients with high basic mRNA level of IL-18 and either low or high mRNA level of TWEAK. The NKp46 immunostaining was stronger in patients with an IL-18 over-expression and a low TWEAK expression, when compared with patients with both IL-18 and TWEAK high expressions. We did not observe any difference for TWEAK expression when recombinant protein IL-18 or its antibody was added, or conversely, for IL-18 expression when TWEAK or its antibody was added in the culture medium. In a pro-inflammatory environment (obtained by an excess of IL-18), inhibition of TWEAK was able to increase significantly NKp46 and TGF-beta1 mRNA expressions.

Conclusions/Significance

TWEAK doesn't act on IL-18 expression but seems to control IL-18 related cytotoxicity on uNK cells when IL-18 is over-expressed. Thus, TWEAK appears as a crucial physiological modulator to prevent endometrial uNK cytotoxicity in human.

Implantation Failure, Etiology, Diagnosis and Treatment

Embryonic implantation is a complex interaction between the embryo and the endometrium. Despite great investigative effort this process is still obscure. Contrary to the great advancement in patient care, follicular recruitment, oocyte quality and aspiration, embryo quality, culture and cryopreservation, our understanding of the implantation process did not enhance as much, and the tools to intervene within this process are limited. The implantation of the transferred embryos still remains the major limiting factor in IVF. Here we will review the current literature on the maternal (uterine, hematologic, immunologic and others) and embryonic factors that are associated with repeated implantation failure (RIF) and describe the various therapeutic approaches to cope with them. In addition, we will present our conclusive recommendations on how to investigate and manage RIF based on the literature and our own experience.

Uterine natural killer cells in peri-implantation endometrium from women with repeated implantation failure after IVF

Several studies have suggested that endometrial uNK (CD56+) cells may play a role in implantation. The aim of this study was to investigate the number of CD56+, CD16+ and CD69+ cells in the unstimulated endometrium of women with recurrent implantation failure after IVF. The percentage of stromal cells positive for CD56, CD16 and CD69 was identified by immunocytochemistry in endometrial biopsies from 15 normal control women and 40 women with recurrent implantation failure. All biopsies were obtained on days LH+7 to LH+9. The density of CD56+ cells in endometrium from women with repeated implantation failure after IVF [median (range) CD56+ cell density=14.5% (1.5-71.4%)] was significantly higher (P=0.005) than in endometrium from control women [5% (2.1-19.2%)]. There was no significant difference in the densities of CD16+ and CD69+ cells in the endometrium from women in the two groups. The increased density of CD56+ cells in the endometrium of women with recurrent implantation failure suggests that these cells are directly involved in the implantation process; alternatively this may indicate a general endometrial defect in these women, which leads to the inability of the embryo to implant.

Fetal rejection: infertility and immunity

Defective reaction toward fetal alloantigens could result in both recurrent spontaneous abortions (RSAs) and recurrent early pregnancy failures (REPFs), the latter existing in couples with unexplained infertility and multiple failures of implantation after in vitro fertilization embryo transfer. Immunological mechanisms leading to RSA and REPF seem to be different, although both syndromes probably have a genetic background that has not been identified so far. Despite the fact that antiphospholipid syndrome is a well-established cause of repeated pregnancy loss, the role of different autoantibodies existing in RSA and REPF patients needs to be elucidated. Immunotherapy is believed to correct the detrimental immune reactions; however, its real effectiveness and safety for the treatment of distinct forms of pregnancy loss need to be reconsidered.

Reduced percentage of natural killer cells associated with impaired cytokine network in the secretory endometrium of infertile women with polycystic ovary syndrome

OBJECTIVE

To evaluate lymphocyte subset distribution in the secretory endometrium from infertile patients with polycystic ovary syndrome (PCOS), and the expression of the cytokines known to play a role in determining the endometrial lymphocyte pattern.

DESIGN

Experimental clinical study.

SETTING

Outpatient clinic in a university hospital.

PATIENT(S)

Twenty-eight patients with PCOS (PCOS group) and 6 fertile patients (control group).

INTERVENTION(S)

On days 22-26 of a spontaneous cycle, subjects underwent endometrial biopsies.

MAIN OUTCOMES MEASURE(S)

In 19 of 28 patients with PCOS and 6 controls with a late secretory endometrium, the percentage and phenotype of lymphocyte subsets were analyzed by flow cytometry. In the late secretory endometrium of 11 patients with PCOS and 3 controls, the expression of interleukins 15 and 18 and of chemokine ligand 10 was also analysed by polymerase chain reaction.

RESULT(S)

In patients with PCOS the percentage of CD56+/CD16- and of CD56bright/CD16- cells was significantly lower (median [confidence interval]: 38% [31%-52.7%] vs. 63.7% [57.7%-69%] and 17.4% [8%-41.6%] vs. 52% [43%-60%], respectively), whereas the percentage of CD3+ was significantly higher (45% [33.3%-64%] vs. 26.1% [21%-32%]) as compared with controls. Accordingly, polymerase chain reaction analysis revealed a significantly lower expression of interleukins 15 and 18 and of chemokine ligand 10 in patients with PCOS than in controls.

CONCLUSION(S)

Results demonstrated an abnormal percentage of endometrial lymphocyte subsets, associated with an impaired cytokine network in patients with PCOS. This could explain the poor reproductive potential in these patients.

STOX1 overexpression in choriocarcinoma cells mimics transcriptional alterations observed in preeclamptic placentas

BACKGROUND

Mutations in STOX1 were proposed to be causal for predisposing to preeclampsia, a hypertensive disorder originating from placental defects, affecting up to 10% of human pregnancies. However, after the first study published in 2005 three other groups have dismissed the polymorphism described in the first paper as a causal mutation.

METHODOLOGY AND PRINCIPAL FINDINGS

In the present study, we have produced a choriocarcinoma cell line overexpressing STOX1. This overexpression results in transcriptional modification of 12.5% of the genes, some of them being direct targets as shown by chromatin immunoprecipitation. STOX1 overexpression correlates strongly and specifically with transcriptomic alterations in preeclamptic placentas (r = 0.30, p = 9.10(-7)). Numerous known key modulators of preeclampsia (such as Endoglin, Syncytin, human chorionic gonadotrophin -hCG-, and Glial Cell Missing Homolog -GCM1-) were modified in these transformed choriocarcinoma cells.

CONCLUSIONS

Our results contribute to reconcile contradictory data concerning the involvement of STOX1 in preeclampsia. In addition, they strongly suggest that anomalies in STOX1 expression are associated with the onset of preeclampsia, thus indicating that this gene should be the target of future studies. Our cellular model could constitute an invaluable resource for studying specific aspects of this human disease.

The increase in metallothionein and ectopic decidual immunoreactivity with respect to the progression of labor at term and the lack of analogical changes in placental abruption

PROBLEM

The coexistence of immune and decidual cells is related to the development of a resistance to immune-mediated apoptosis in both ectopic and eutopic decidua. This unique feature of endometrial cells seems to be linked with the expression of metallothionein (MT), an inhibitor of apoptosis.

METHOD OF STUDY

The MT immunoreactivity level was assessed in 82 eutopic (CC) and ectopic (cesarean scar deciduosis - CSD) decidual tissue samples obtained from patients during cesarean sections at term and from patients on whom cesarean sections were performed on account of placental abruption (PA).

RESULT

Statistically, significantly higher levels of MT immunoreactivity were found in eutopic and ectopic decidua sampled during cesarean sections performed on patients with advanced labor when compared to the levels found in tissues sampled during cesarean sections on patients without labor. No differences were observed in the MT immunoreactivity levels in decidual tissue samples derived from patients who had undergone cesarean sections on account of PA with respect to the progression of labor at the time of the surgical procedure. Statistically, the decidual MT immunoreactivity levels were significantly higher in the PA than the CC subgroups and in the PA than the CSD subgroups correlating with the stage of labor.

CONCLUSION

MT in decidual cells seems to be responsible for the proper coexistence between decidual cells and activated immune cells that infiltrate both eutopic and ectopic decidua during cesarean section and PA.

The role of decidual natural killer cells in normal placentation and in the pathogenesis of preeclampsia

Adequate invasion of the human placenta during the first weeks of pregnancy is a critical step in ensuring both fetal and maternal health. A rapidly expanding body of evidence suggests that decidual natural killer (dNK) cells, a distinct population of CD56brightCD16- lymphocytes, are key regulators of this complex process. Experiments using murine models and in vitro evidence using human tissue cultures suggest that dNK cells modulate extravillous trophoblast (EVT) invasion and remodelling of maternal spiral arteries via both contact-dependent and contact-independent mechanisms. In addition, the differential expression of surface receptors by dNK cells may have a role in determining reproductive success through modulation of the maternal immune system at the time of implantation and placentation. The roles of cytokines, chemokines, and growth factors secreted by dNK cells and their influence on EVT migration, invasion, and pseudovasculogenesis are of particular interest. We reviewed the available experimental evidence related to the functional relationships between dNK cells and trophoblasts at the time of placentation to elucidate potential clinical correlations with human pathologies, including preeclampsia, recurrent pregnancy loss, IVF failure, and placenta accreta.

Gene expression profiling of human peri-implantation endometria between natural and stimulated cycles

OBJECTIVE

To investigate the effect of high serum E(2) levels in gonadotropin-stimulated cycles (hCG+7) on the gene expression patterns of human endometrium compared with natural cycles on the seventh day of LH surge (LH+7) and elucidate the underlying molecular changes that may be related to endometrial receptivity.

DESIGN

Observational study.

SETTING

University Hospital.

PATIENTS(S)

Infertile patients with normal menstrual cycles undergoing IVF treatment.

INTERVENTION(S)

Gonadotropin stimulation and endometrial biopsy.

MAIN OUTCOME MEASURE(S)

Gene expression by microarray and quantitative polymerase chain reaction (qPCR).

RESULT(S)

Endometrial samples from natural (n = 5) and stimulated (n = 8) cycles were collected. Patients in the stimulated cycles were classified as moderate (n = 4) or excessive (n = 4) responders if their serum E(2) levels on the day of administration of hCG were <or=20,000 pmol/L or >20,000 pmol/L, respectively. The RNA transcripts were profiled by Affymetrix HG-U133A microarray. Clustering and principal component analysis demonstrated a significant difference (>or=2-fold) in the expression patterns of 411 genes among the three groups. Putative estrogen response elements or progesterone response elements were identified in the promoter regions of 49 differentially expressed genes of diverse biologic functions. The qPCR confirmed the microarray result in 47 endometrial samples.

CONCLUSION(S)

High serum E(2) and/or progesterone modulate the gene expression profiles of human endometrium and may affect endometrial receptivity.

Polymorphisms in the interleukin-12/18 genes and recurrent spontaneous abortion

PROBLEM

Interleukin (IL) IL-12/IL-18 are involved in uterine NK cells control of uterine vascular development. Polymorphisms in the IL-12/IL-18 genes could modify the cytokine balance, which might result in an increased susceptibility to recurrent spontaneous abortion (RSA).

METHOD OF STUDY

A case-control study was conducted to determine the association between the IL12 (I/D) and IL18 (-607C>A, -137G>C) gene polymorphisms and the risk of RSA in 125 women with RSA and in 136 controls.

RESULTS

The frequencies of DD, ID, II for IL-12 were, 25.6%, 52.8% and 21.6% respectively, in patients versus 21.3%, 51.5% and 27.2% respectively in controls; the frequencies of CC, CA, AA genotypes for IL-18 (-607) were, 34.4%, 54.4% and 11.2% respectively in patients versus 30.1%, 58.1% and 11.8% respectively in controls; the frequencies of GG, GC, CC genotypes for IL-18(-137) were 47.2%, 43.2% and 9.6% respectively in patients and 45.6%, 46.3% and 8.1% respectively in controls.

CONCLUSION

IL-12B and IL-18 promoter gene polymorphisms were not associated with RSA in our women.

Angiogenesis in implantation

PROBLEM

Implantation failure and early pregnancy loss are common following natural conceptions and they are particularly important clinical hurdles to overcome following assisted reproduction attempts. The importance of adequate vascular development and maintenance during implantation has recently become a major focus of investigation.

MATERIALS AND METHODS

Review of current published literature was undertaken to summerize the cells and cell products that regulate tissue vascularity during implantation.

RESULTS

Vascular development at the maternal fetal interface can be regulated by a number of different cell types; two principal candidates are trophoblast and natural killer cells. A wide range of soluble factors, some with well established angiogenic functions as well as other more novel factors, can contribute to vascular development and maintenance at the maternal-fetal interface.

CONCLUSIONS

Robust vascular development occurs during implantation and early placentation of normal pregnancies. Studies to define the extent and mechanisms by which defects in vascularity contribute to human implantation failure and early miscarriage need to be undertaken.

Cytokines: Important for implantation?

PROBLEM

Cytokines are obviously very important in an established pregnancy, but what about human embryo implantation?

METHODS

Literature review.

RESULTS

We first discuss the necessity and limits of animal models, and then review the few cytokines which have been demonstrated by knock-out methods to be absolutely necessary for embryo implantation using in animal models. We then review what is known or discussed about the role of other cytokines as deduced from quantitative and/or qualitative dysregulation in animals and in humans.

CONCLUSIONS

Cytokines are indeed involved in implantation as they are in ongoing pregnancy and delivery. Relevance to infertility and recurrent pregnancy loss is discussed.

RCAS1 decidual immunoreactivity in severe pre-eclampsia: immune cell presence and activity

PROBLEM

Pre-eclampsia seems to be related to the disturbance of immune tolerance regulation during pregnancy. Receptor-binding cancer antigen expressed on SiSo cells (RCAS1) decidual level alterations were concomitant with changes in immune cell number and activity in decidua. As decidual immunomodulating activity participates in the development of immune tolerance during pregnancy, we aimed to evaluate the immunoreactivity level of decidual RCAS1 with respect to the presence and activity of immune cells.

METHOD OF STUDY

RCAS1, CD3, CD56, CD69, and CD25 immunoreactivity was assessed by immunohistochemistry in 30 decidual samples derived from patients with severe pre-eclampsia (sPE) and from a healthy control group.

RESULTS

RCAS1 immunoreactivity was statistically significantly higher in decidual tissue samples derived from patients with sPE tissue than in those derived from healthy patients in whom elective cesarean section at term was performed. A statistically significantly lower number of CD56(+) and CD3(+) cells and lower immunoreactivity level of CD69 were found in patients with sPE compared with those from the control group.

CONCLUSION

The limited immune cells infiltration in decidua during sPE is associated with increase in RCAS1 decidual level.

[Physiology of implantation]

This article explains why we have had to come to a central role for innate immunity rather than the threat of maternal rejection of the foetal allograft. We encompass briefly the role of inflammation in implantation, not only for invasion adhesion, but also to prepare future "tolerance". In this context, we envisage the role of TWEAK and complement.

Prognostic value of the measurement of uterine natural killer cells in the endometrium of women with recurrent miscarriage

BACKGROUND

Studies in mice suggest that CD56 + uterine natural killer (uNK) cells play an important role in implantation. Studies in humans have described an increase in the number of uNK cells in the non-pregnant mid-secretory endometrium of women with unexplained recurrent miscarriage (RM). However, the predictive value of uNK cell number in the maintenance of pregnancy is controversial.

METHODS

A blind retrospective study was undertaken. The percentage of stromal cells positive for CD56 was identified by immunocytochemistry in endometrial biopsies from 10 normal control women and 87 women with unexplained RM, of whom 51 became pregnant following biopsy. Biopsies were obtained on days LH + 7 to LH + 9.

RESULTS

As in previous studies, the number of uNK cells in the 87 women with RM (mean 11.2% range 1.1-41.4%) was significantly higher (P = 0.013) than in the control women (mean 6.2% range 2.2-13.9%). No significance difference in uNK numbers was observed between 19 women who miscarried (mean 9.6% range 1.7-25.0%) and 32 women who had a live birth (mean 13.3% range 1.1-41.4%) in a subsequent pregnancy.

CONCLUSIONS

In this study numbers of uNK cells in the peri-implantation endometrium of women with unexplained recurrent miscarriage did not predict subsequent pregnancy outcome.

The Th1/Th2 paradigm: still important in pregnancy?

The enunciation of the T helper 1/T helper 2 (Th1/Th2) paradigm in pregnancy has represented a major step forward in our understanding of physiological and pathologic materno-foetal relationship. However, recent developments in studies of the implantation process and in the emergence of the uterine vascular bed and its control by natural killer cells and cytokines suggest that one must go beyond this hitherto useful scheme. In this review, we replace the emergence of the paradigm in its historical context and then emphasises what it does explain and what it no longer account for. A final reappraisal of the paradigm is suggested.

Oocyte aneuploidy mechanisms are different in two situations of increased chromosomal risk: older patients and patients with recurrent implantation failure after in vitro fertilization

OBJECTIVE

To clarify the mechanisms underlying oocyte abnormalities in meiosis: meiotic nondisjunction of a whole chromosome or premature separation of sister chromatids in two situations of increased chromosomal risk.

DESIGN

Preconception diagnosis by first polar-body analysis in two situations of increased chromosomal risk.

SETTING

Departments of reproductive biology, cytogenetics, gynecology, and obstetrics.

PATIENT(S)

First polar body analysis was proposed to 76 patients (91 cycles) for advanced age (AMA; n = 30, 36 cycles), recurrent implantation failure (RIF; >10 embryos transferred without implantation; n = 32, 36 cycles), or both (AMA + RIF; n = 14, 19 cycles), before their intracytoplasmic sperm injection procedure.

INTERVENTION(S)

First polar-body analysis using fluorescence in situ hybridization.

MAIN OUTCOME MEASURE(S)

Mechanisms and frequency of aneuploidy.

RESULT(S)

Three hundred eighty-four oocytes were analyzed by fluorescence in situ hybridization, 130 from women >38 years of age, 171 from women with RIF, and 83 from women with both indications. The oocyte abnormality rate was similar in the three groups, respectively, 38.5%, 40.4%, and 45.8%. The aneuploidy mechanisms were different for women >38 years of age who had no previous implantation failure (AMA) compared with women of whatever age who had implantation failure (P<.05 vs. RIF; P<.001 vs. AMA+RIF), with, respectively, for the AMA, RIF, and AMA+RIF groups, 72.2%, 56.6%, and 49.2% premature separation of sister chromatids and 27.8%, 43.4%, and 50.8% meiotic nondisjunction. In the two implantation-failure groups, we distinguished a subgroup (22% in the RIF group and 33% in AMA+RIF group) of patients with >2/3 abnormal oocytes, suggesting a meiosis alteration.

CONCLUSION(S)

The mechanisms accounting for oocyte aneuploidy differed in the two clinical situations of advanced maternal age and RIF. Advanced maternal-age aneuploidy was linked to a loss of sister chromatid cohesion that led to one single chromatid abnormality, whereas implantation failure is a much more heterogeneous situation.