Fetus specific T cell modulation during fertilization, implantation and pregnancy

Pregnancies through oocyte donation. A mini review of pathways involved in placental dysfunction

Pregnancies resulting from assisted reproductive techniques (ART) are increasingly prevalent worldwide. While most pregnancies conceived through in-vitro fertilization (IVF) progress without complications, mounting evidence suggests that these pregnancies are at a heightened risk of adverse perinatal outcomes. Specifically, IVF pregnancies involving oocyte donation have garnered attention due to numerous reports indicating an elevated risk profile for pregnancy-related complications within this subgroup of patients. The precise mechanisms contributing to this increased risk of complications remain incompletely understood. Nonetheless, it is likely that they are mediated by an abnormal immune response at the fetal-maternal interface. Additionally, these outcomes may be influenced by baseline patient characteristics, such as the etiology of infertility, absence of corpus luteum, and variations in endometrial preparation protocols, among other factors. This review aims to succinctly summarize the most widely accepted mechanisms that potentially contribute to the onset of placental dysfunction in pregnancies conceived through oocyte donation.

Altered Thermal Behavior of Blood Plasma Proteome Related to Inflammatory Cytokines in Early Pregnancy Loss

Early pregnancy loss (EPL) is a relatively common pathology of which almost 50% of cases remain idiopathic. In the search for novel biomarkers, differential scanning calorimetry (DSC) is intensively used to characterize the thermodynamic behavior of blood plasma/serum proteome in health and disease. Herein, for the first time, we investigate the DSC denaturation profiles of blood plasma derived from patients suffering EPL compared to healthy pregnant and non-pregnant women. Data analysis reveals that 58% of the EPL thermograms differ significantly from those of healthy pregnant women. Thermal stabilization of a fraction of albumin-assigned transition with concomitant suppression of the major and enhancement of the globulin-assigned transition are characteristic features of EPL calorimetric profiles that could be used as a new indicator of a risk pregnancy. The presented results suggest an altered composition or intermolecular interactions of the plasma proteome of women with EPL. In addition, the alterations of the EPL thermograms correlate with the increased blood levels of tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6) and a higher prevalence of the polymorphism in the plasminogen activator inhibitor type-1 (PAI-1) gene, suggesting an expression of an overall enhanced immune response. The concomitant changes in plasma thermograms confirm the potential of the DSC approach for distinguishing changes in the pathological state of the blood plasma proteome.

Histology Atlas of the Developing Mouse Placenta

The use of the mouse as a model organism is common in translational research. This mouse-human similarity holds true for placental development as well. Proper formation of the placenta is vital for development and survival of the maturing embryo. Placentation involves sequential steps with both embryonic and maternal cell lineages playing important roles. The first step in placental development is formation of the blastocyst wall (approximate embryonic days [E] 3.0-3.5). After implantation (∼E4.5), extraembryonic endoderm progressively lines the inner surface of the blastocyst wall (∼E4.5-5.0), forming the yolk sac that provides histiotrophic support to the embryo; subsequently, formation of the umbilical vessels (∼E8.5) supports transition to the chorioallantoic placenta and hemotrophic nutrition. The fully mature ("definitive") placenta is established by ∼E12.5. Abnormal placental development often leads to embryonic mortality, with the timing of death depending on when placental insufficiency takes place and which cells are involved. This comprehensive macroscopic and microscopic atlas highlights the key features of normal and abnormal mouse placental development from E4.5 to E18.5. This in-depth overview of a transient (and thus seldom-analyzed) developmental tissue should serve as a useful reference to aid researchers in identifying and describing mouse placental changes in engineered, induced, and spontaneous disease models.

Pro- and Anti-Inflammatory Cytokines in the First Trimester-Comparison of Missed Miscarriage and Normal Pregnancy

The advantage in response of Th2 over Th1 is observed in normal pregnancy in peripheral blood. A disturbance of this balance can lead to symptoms of miscarriage and pregnancy loss. The aim of this study was to evaluate the pro- and anti-inflammatory cytokines in sera of women who were diagnosed with missed miscarriage in the first trimester and to compare this systemic immune response to the response in women with normal pregnancy. The study group consisted of 61 patients diagnosed with missed miscarriage. In total, 19 healthy women with uncomplicated first trimester created the control group. Cytokines were determined in the maternal serum by ELISA. The analysis included INF-γ, TNF-α, Il-1β, Il-4, Il-5, Il-6, Il-9, Il-10, Il-13 and TGF-β1. Th1 cytokine levels in the study group reached slightly higher values for INF-γ, Il-1β and slightly lower for IL-6 and TNF-α. In turn, Th2 cytokine levels in the study group were slightly higher (Il-9, Il-13), significantly higher (Il4, p = 0.015; Il-5, p = 0.0003) or showed no differences with the control group (Il-10). Slightly lower concentration involved only TGF-β1. Analysis of the correlation between levels of pro- and anti-inflammatory cytokines resulted in some discrepancies, without showing predominance of a specific immune response. The results did not confirm that women with missed miscarriage had an advantage in any type of immune response in comparison to women with normal pregnancy.

Insights Into Extracellular Vesicle/Exosome and miRNA Mediated Bi-Directional Communication During Porcine Pregnancy

Spontaneous fetal loss is one of the most important challenges that commercial pig industry is still facing in North America. Research over the decade provided significant insights into some of the associated mechanisms including uterine capacity, placental efficiency, deficits in vasculature, and immune-inflammatory alterations at the maternal-fetal interface. Pigs have unique epitheliochorial placentation where maternal and fetal layers lay in opposition without any invasion. This has provided researchers opportunities to accurately tease out some of the mechanisms associated with maternal-fetal interface adaptations to the constantly evolving needs of a developing conceptus. Another unique feature of porcine pregnancy is the conceptus derived recruitment of immune cells during the window of conceptus attachment. These immune cells in turn participate in pregnancy associated vascular changes and contribute toward tolerance to the semi-allogeneic fetus. However, the precise mechanism of how maternal-fetal cells communicate during the critical times in gestation is not fully understood. Recently, it has been established that bi-directional communication between fetal trophoblasts and maternal cells/tissues is mediated by extracellular vesicles (EVs) including exosomes. These EVs are detected in a variety of tissues and body fluids and their role has been described in modulating several physiological and pathological processes including vascularization, immune-modulation, and homeostasis. Recent literature also suggests that these EVs (exosomes) carry cargo (nucleic acids, protein, and lipids) as unique signatures associated with some of the pregnancy associated pathologies. In this review, we provide overview of important mechanisms in porcine pregnancy success and failure and summarize current knowledge about the unique cargo containing biomolecules in EVs. We also discuss how EVs (including exosomes) transfer their contents into other cells and regulate important biological pathways critical for pregnancy success.

Innate Lymphoid Cells and Adaptive Immune Cells Cross-Talk: A Secret Talk Revealed in Immune Homeostasis and Different Inflammatory Conditions

The inflammatory immune response has evolved to protect the host from different pathogens, allergens, and endogenous death or damage-associated molecular patterns. Both innate and adaptive immune components are crucial in inducing an inflammatory immune response depending on the stimulus type and its duration of exposure or the activation of the primary innate immune response. As the source of inflammation is removed, the aggravated immune response comes to its homeostatic level. However, the failure of the inflammatory immune response to subside to its normal level generates chronic inflammatory conditions, including autoimmune diseases and cancer. Innate lymphoid cells (ILCs) are newly discovered innate immune cells, which are present in abundance at mucosal surfaces, including lungs, gastrointestinal tract, and reproductive tract. Also, they are present in peripheral blood circulation, skin, and lymph nodes. They play a crucial role in generating the pro-inflammatory immune response during diverse conditions. On the other hand, adaptive immune cells, including different types of T and B cells are major players in the pathogenesis of autoimmune diseases (type 1 diabetes mellitus, rheumatoid arthritis, psoriasis, and systemic lupus erythematosus, etc.) and cancers. Thus the article is designed to discuss the immunological role of different ILCs and their interaction with adaptive immune cells in maintaining the immune homeostasis, and during inflammatory autoimmune diseases along with other inflammatory conditions (excluding pathogen-induced inflammation), including cancer, graft-versus-host diseases, and human pregnancy.

NK cell subsets in idiopathic recurrent miscarriage and renal transplant patients

The present review article compares NK cell subsets and cytokine patterns determined in the peripheral blood as well as results of functional in-vitro assays using peripheral NK cells of idiopathic recurrent miscarriage (iRM) patients with corresponding results obtained in female healthy controls and female renal transplant recipients with good long-term graft function. Immune mechanisms, inducing transplant rejection in long-term transplant recipients might also be able to induce rejection of semi-allogeneic fetal cells in patients with iRM. Consequently, the immune status of transplant recipients with good stable long-term graft function should be different from the immune status of iRM patients. iRM patients show a strong persistent cytotoxic NK cell response in the periphery. Simultaneously, immunostimulatory Th1 as well as immunosuppressive Th2 type lymphocytes in the blood are strongly activated but plasma levels of immunosuppressive Th2 type cytokines are abnormally low. In-vitro, unstimulated NK cell cultures of iRM patients show a strong spontaneous TGF-ß1 release in the supernatant but lower TGF-ß1 levels after stimulation with tumor cell line K562, suggesting strong consumption of TGF-ß1 by pre-activated NK cells of iRM patients that might contribute to the low systemic Th2 type plasma levels. iRM patients do not show a systemic switch to a Th2 type cytokine pattern and one might hypothesize that low TGF-ß plasma levels indicate low TGF-ß levels in the micromilieu immediately before fetal rejection. Persistent TGF-ß deficiency implies a persistent unfavorable micromilieu for pregnancy resulting in failing tolerance induction due to lack of TGF-ß, a condition that might contribute to iRM.

Expression of E2A in mid-secretory endometrium of women suffering from recurrent miscarriage

E2A is involved in promoting forkhead box P3 (FOXP3) and retinoid-related orphan receptor gamma t (RORγt) gene transcription, which are pivotal transcription factors of T regulatory cells and Th17 cells, respectively. Little is known about the involvement of E2A in pregnancy process. This study aimed to investigate the expression of E2A, cytotoxic T-lymphocyte-associated protein 4 (CTLA-4), and Foxp3 in luteal phase endometrium of women suffering recurrent miscarriage (RM) (n=21) and control group (n=11) by immunohistochemistry, with the Vectra® automated quantitative pathology imaging system for analysis. The percentage of E2A+ cells and CTLA-4+ cells was significantly higher in the endometrium of women with RM than in the controls. There was positive correlation between E2A and CTLA-4 (r=0.523, P=0.002), E2A and FOXP3 (r=0.380, P=0.032), and FOXP3 and CTLA-4 (r=0.625, P=0.000) in the mid-secretory phase of endometrium for all subjects. It was concluded that the abnormal expression of endometrial E2A existed in mid-secretory endometrium of women with RM, and there was a positive correlation between E2A and FOXP3, and E2A and CTLA-4, suggesting the possible regulation role of E2A involved in regulating endometrium receptivity.

Pregnancy and spontaneous fetal loss: A pig perspective

Pigs have a unique, non-invasive epitheliochorial placenta where maternal and fetal layers lay in apposition. Indentation of fetal capillaries into the trophoblasts and maternal capillaries into the uterine epithelium reduce the distance between the fetal and maternal blood, ensuring nutrient transfer for proper conceptus development. Another unique feature of pig pregnancy is conceptus-mediated immune cell enrichment during the early stages of conceptus attachment (around gestation Day 15). This period coincides with the development of vasculature networks at the maternal-fetal interface, which is critical for successful conceptus growth. Specific chemokines, their receptors, and chemokine decoy receptor networks coordinate this immune cell enrichment and the positioning at the maternal-fetal interface. The recruited immune cells, in turn, adopt a specialized phenotype to support key processes of maternal-fetal adaptations, including tolerance to the semi-allogeneic fetus and supporting vascularization. Disturbance in coordinated cross talk between the conceptus and maternal endometrium is an important mechanism associated with spontaneous fetal loss. The exact mechanism of fetal loss is still not yet identified, although research in the last two decades point to various factors including genetics, nutrition, uterine capacity, placental efficiency, and imbalanced immune factors at the maternal-fetal interface. In this review, we summarize some of the recent advances in endometrial immune cell functions and their regulation. We also provide insights into endometrial/placental transcriptome, microRNA biology, and extravesicular transport across the maternal-fetal interface, as well as their potential implications in porcine pregnancy success or failure.

Bone mesenchymal stem cells improve pregnancy outcome by inducing maternal tolerance to the allogeneic fetus in abortion-prone matings in mouse

INTRODUCTION

The successful pregnancy depends on maternal immune tolerance against the fetus. It has been reported that MSCs (mesenchymal stem cells) could play a regulatory role on immune cells such as CD4⁺T cells, macrophages and NK cells, but their effect on recurrent miscarriage is unknown.

STUDY DESIGN

In a prospective study, the abortion-prone (CBA/J × DBA/2) H-2^d × H-2^k mice were utilized. Female CBA/J mice (8-10 weeks old) were injected with vehicle or MSCs via tail vein or uterine horns, and 14 days later, they were mated with DBA/2 males for the following experiments.

RESULTS

Comparing with the control group, the embryo resorption rate in MSCs-horn injection group was dramatically decreased. MSCs were mainly located at the maternal-fetal interface, indicating that the reduction of resorption rate was due to MSCs' local effect. No matter which treatment was given, there was no significant difference in the levels of IL-4, IL-10, TNF-α and IFN-γ in CD4⁺T cells and IL-10 and IL-12 in macrophages in spleens among each group. However, in contrast to other groups, the levels of IL-4 and IL-10 in CD4⁺T cells localized at the maternal-fetal interface in MSCs-horn injection group were dramatically increased, and TNF-α and IFN-γ levels were notably decreased. While IL-10 expressed in macrophages was obviously higher than other groups and IL-12 in macrophages was significantly lower than other groups.

CONCLUSIONS

The findings indicate that MSCs injection through uterine horns could decrease embryo resorption rate.

Immunologic challenges of human reproduction: an evolving story

Characterization of the implanting human fetus as an allograft prompted a field of research in reproductive immunology that continues to fascinate and perplex scientists. Paternal- or partner-derived alloantigens are present in the maternal host at multiple times during the reproductive process. They begin with exposure to semen, continue through implantation and placentation, and may persist for decades in the form of fetal microchimerism. Changes in maternal immune responses that allow allogenic fertilization and survival of semiallogenic concepti to delivery must be balanced with a continued need to respond appropriately to pathogenic invaders, commensals, cell or tissue damage, and any tendency toward malignant transformation. This complex and sophisticated balancing act is essential for survival of mother, fetus, and the species itself. We will discuss concepts of alloimmune recognition, tolerance, and ignorance as they pertain to mammalian reproduction with a focus on human reproduction, maternal immune modulation, and the very earliest events in the reproductive process, fertilization and implantation.

What is wrong with the regulatory T cells and foetomaternal tolerance in women with recurrent miscarriages?

Couples of whom the woman has had a miscarriage have two major concerns: the cause and possible risk of recurrence. Unfortunately, a significant proportion of cases of recurrent miscarriage (RM) remain unexplained despite detailed investigation. Because data suggest that regulatory T cells (Treg) are involved in the maternal acceptance of the allogeneic foetus, RM could possibly be explained by a disturbance of the Treg network. The possible role of Tregs in RM is described in this review, as well as their potential application in diagnostics and therapeutic intervention trials.

Complexes of trophoblastic peptides and heat shock protein 70 as a novel contraceptive vaccine in a mouse model

The concept of contraceptive vaccines has interested reproductive biologists and immunologists for nearly 2 decades, but no approach has been approved. In this study, a new immunocontraceptive vaccine that targets placental trophoblasts was expored. We demonstrated that after in-vitro binding with heat shock protein 70, trophoblast-derived peptides can activate T cells both in vitro and in vivo. The activated T cells have a Th1 bias and specifically cause cytolysis of trophoblasts, leading to the termination of pregnancy. Such activated T cells seem to have an effect on early gestation, rather than influencing preimplantation. We did not observe side-effects of this vaccine in mice. In conclusion, a novel contraceptive strategy is described that uses heat shock protein 70-trophoblastic peptide complexes to generate a specific T-cell immune response against placental trophoblasts. This type of vaccine targeting the post-implantation phase does not generate a permanent effect but possibly raises an ethical issue.

T regulatory markers expression in unexplained recurrent spontaneous abortion

OBJECTIVE

To evaluate expression of glucocorticoid-induced tumor necrosis factor receptor (GITR), cytotoxic T lymphocyte-associated antigen 4 (CTLA-4) and IL-10 in peripheral blood mononuclear cells (PBMCs) of 20 women with unexplained recurrent spontaneous abortion (URSA) compared to 20 normal non-pregnant women (NNP) during luteal phase in the window of implantation.

METHODS

Quantitative real-time PCR (qRT-PCR) was performed using the Taqman method for expression of GITR and SYBR Green method for expression of CTLA-4 and IL-10.

RESULTS

Expression of CTLA-4 in the NNPs (median; interquartile range; 3; 1.8-10) was significantly higher than the URSAs (0.72; 0.26-3.81, p = 0.015). Expression of GITR in the NNPs (53; 10-139) was significantly higher than the URSAs (6; 3-27, p = 0.005). However, IL-10 expression in the URSAs was significantly higher than the NNPs, did not meet a significant value. A significant correlation was found between CTLA-4 and GITR expression in the study population (p = 0.0001).

CONCLUSIONS

Expression of CTLA-4 and GITR were significantly down-regulated in the URSAs compared to NNPs at the window of implantation, which shows the essential role of Treg cells in creating an immunological privileged site for fetus as an allograft at the maternal-fetal interface by high expression levels of CTLA-4 and GITR during a normal pregnancy.

Regulatory T cells ameliorate intrauterine growth retardation in a transgenic rat model for preeclampsia

Preeclampsia is a multisystemic syndrome during pregnancy that is often associated with intrauterine growth retardation. Immunologic dysregulation, involving T cells, is implicated in the pathogenesis. The aim of this study was to evaluate the effect of upregulating regulatory T cells in an established transgenic rat model for preeclampsia. Application of superagonistic monoclonal antibody for CD28 has been shown to effectively upregulate regulatory T cells. In the first protocol (treatment protocol), we applied 1 mg of CD28 superagonist or control antibody on days 11 and 15 of pregnancy. In the second protocol (prevention protocol), the superagonist or control antibody was applied on days 1, 5, and 9. Superagonist increased regulatory T cells in circulation and placenta from 8.49±2.09% of CD4-positive T cells to 23.50±3.05% and from 3.85±1.45% to 23.27±7.64%, respectively. Blood pressure and albuminuria (30.6±15.1 versus 14.6±5.5 mg/d) were similar in the superagonist or control antibody-treated preeclamptic group for both protocols. Rats treated with CD28 superagonist showed increased pup weights in the prevention protocol (2.66±0.03 versus 2.37±0.05 g) and in the treatment protocol (3.04±0.04 versus 2.54±0.1 g). Intrauterine growth retardation, calculated by brain:liver weight ratio, was also decreased by the superagonist in both protocols. Further analysis of brain development revealed a 20% increase in brain volume by the superagonist. Induction of regulatory T cells in the circulation and the uteroplacental unit in an established preeclamptic rat model had no influence on maternal hypertension and proteinuria. However, it substantially improved fetal outcome by ameliorating intrauterine growth retardation.

Post-partum reactivation of chronic hepatitis B virus infection among hepatitis B e-antigen-negative women

AIM: To investigate the frequency and timing of post-partum chronic hepatitis B virus (HBV) reactivation and identify its pre-partum predictors.

METHODS: Forty-one hepatitis B e antigen (HBeAg)-negative chronic HBV infected pregnant women were prospectively evaluated between the 28^th and the 32^nd week of gestation. Subjects were re-evaluated at 3-mo intervals during the first post-partum year and every 6 mo during the following years. HBV DNA was determined using real-time reverse transcription polymerase chain reaction (Cobas TaqMan HBV Test) with a lower detection limit of 8 IU/mL. Post-partum reactivation (PPR) was defined as abnormal alanine aminotransaminase (ALT) levels and HBV DNA above 2000 IU/mL.

RESULTS: Fourteen out of 41 women (34.1%) had pre-partum HBV DNA levels > 2000 IU/mL, 18 (43.9%) had levels < 2000 IU/mL and 9 (21.9%) had undetectable levels. Fourteen women were lost to follow-up (failure to return). PPR occurred in 8 of the 27 (29.6%) women evaluated, all within the first 6 mo after delivery (5 at month 3; 3 at month 6). Five of the 6 (83.3%) women with pre-partum HBV DNA > 10000 IU/mL exhibited PPR compared with 3 of the 21 (14.3%) women with HBV DNA < 10000 IU/mL (two with HBV DNA > 2000 and the third with HBV DNA of 1850 IU/mL), P = 0.004. An HBV DNA level ≥ 10000 IU/mL independently predicted post-partum HBV infection reactivation (OR = 57.02, P = 0.033). Mean pre-partum ALT levels presented a non-significant increase in PPR cases (47.3 IU/L vs 22.2 IU/L, respectively, P = 0.094).

CONCLUSION: In the present study, PPR occurred in approximately 30% of HBeAg-negative pregnant women; all events were observed during the first semester after delivery. Pre-partum HBV DNA level > 10000 IU/mL predicted PPR.

Maternal HLA-C2 and 14 bp insertion in HLA-G is associated with recurrent implantation failure after in vitro fertilization treatment

The major rate-limiting step in in vitro fertilization (IVF) success appears to be the implantation of the semi-allogeneic embryo into the maternal endometrium. To determine possible risk factors of recurrent failure of embryos to implant, we investigated immunogenetic determinants as level of human leukocyte antigen (HLA) histocompatibility, frequency of killer-cell immunoglobulin-like receptors (KIR) and HLA-C alleles and HLA-G polymorphism. We DNA typed women with recurrent implantation failure (RIF) and their partners for classical HLA Class I, HLA Class II, HLA-G and KIR alleles and compared these results with couples with successful embryo implantation after their first IVF and normal fertile couples. No association was found between RIF and the degree of histocompatibility between partners or sharing of a specific antigen. Also, no significant difference in KIR haplotype or combination of HLA-C group and KIR was observed. We did find a higher frequency of HLA-C2 and a higher frequency of 14 base pair (bp) insertion in HLA-G in women with RIF. Therefore we conclude that the degree of histocompatibility between partners is not a determining factor for the occurrence of RIF. However, presence of the HLA-C2 allotype and the HLA-G allele with a 14 bp insertion is a significant risk factor.

Fetal-maternal interface: a chronicle of allogeneic coexistence

The existence of allogeneic cells within an individual has been demonstrated in multiple fields such as hematopoietic stem cell or solid organ transplantation, non-depleted blood transfusions and the most common form which is bidirectional maternal-fetal cell trafficking, whereby cells from the fetus pass through the placental barrier. In order to graphically illustrate this early natural phenomenon that initiates the journey of a child’s cells within the mother’s blood and other tissues, we used a new procedure in microscopy imaging generating Large Scale Panoramic Pictures (LSPP). This technique can also be extended to explore a broad diversity of experimental models.

An immunological basis for chronic histiocytic intervillositis in recurrent fetal loss

PROBLEM

Chronic histiocytic intervillositis (CHIV) is a rare type of placental pathology that is associated with reproductive loss at all gestational ages. The aim of the study was to investigate the relationship between the severity of CHIV and the outcome of pregnancy and to compare the immune response between CHIV patients and controls to explore an immunological origin of CHIV.

METHOD OF STUDY

Microscopic slides were reviewed and scored according to a previously published grading system in 30 pregnancies of 22 CHIV patients. Partner-specific mixed lymphocyte reactions, cytotoxic T-lymphocyte precursor frequencies (CTLpf), and anti-HLA antibodies were determined in four patients and seven controls.

RESULTS

Higher CHIV scores are associated with worse pregnancy outcome. CHIV patients demonstrated a higher CTLpf against their partner compared to non-complicated pregnancies (P = 0.03). The CTLpf was extremely high in 75% of the patients. Antipaternal HLA antibodies were only present in 75% of the CHIV patients compared to none of the controls (P = 0.02).

CONCLUSION

CHIV scores seem to be associated with the severity of adverse pregnancy outcome. High antipaternal cellular (T-cell) and humoral (B-cell) response to partner-specific CTLpf and the presence of anti-HLA antibodies directed to the partner suggest an immunologic origin of CHIV.

The Placenta in Toxicology. Part II

During pregnancy, the maternal immune system is challenged by the semiallogeneic fetus, which must be tolerated without compromising fetal or maternal health. This review updates the systemic and local immune changes taking place during human pregnancy, including some examples in rodents. Systemic changes are induced by contact of maternal blood with placental factors and include enhanced innate immunity with increased activation of granulocytes and nonclassical monocytes. Although a bias toward T helper (Th2) and regulatory T cell (Treg) immunity has been associated with healthy pregnancy, the relationship between different circulating Th cell subsets is not straightforward. Instead, these adaptations appear most evidently at the fetal–maternal interface, where for instance Tregs are enriched and promote fetal tolerance. Also innate immune cells, that is, natural killer cells and macrophages, are enriched, constituting the majority of decidual leukocytes. These cells not only contribute to immune regulation but also aid in establishing the placenta by promoting trophoblast recruitment and angiogenesis. Thus, proper interaction between leukocytes and placental trophoblasts is necessary for normal placentation and immune adaptation. Consequently, spontaneous maladaptation or interference of the immune system with toxic substances may be important contributing factors for the development of pregnancy complications such as preeclampsia, preterm labor, and recurrent miscarriages.

Donor chimera model for tolerance induction in transplantation

Tolerance induction is the basis of a successful transplantation with the goal being the re-establishment of homeostasis after transplantation. Non-autograft transplantation disrupts this maintenance drastically which would be avoided by administration of a novel procedure. At present, the blood group antigens and the genotypes of the donor and recipient are cross-matched before transplantation combined with a drug regimen that confers general immunosuppression. But the 'specific' unresponsiveness of the recipient to the donor organ, implied by 'tolerance', is not achieved in this process. This article introduces the 'donor chimera model' via the concept of the 'closed transplantation loop' approach for tolerance induction which seeks to limit the use of immunosuppressive therapy after transplantation.

Defective soil for a fertile seed? Altered endometrial development is detrimental to pregnancy success

Background

Synchronous development of the endometrium (to achieve a receptive state) and of the embryo is essential for successful implantation and ongoing pregnancy. Endometrial receptivity exists only for a finite time in a menstrual cycle and the endometrium is refractory to embryo implantation outside of this window. Administration of hormones to stimulate multifollicular development within the ovary, integral to the majority of assisted reproduction (ART) protocols, dramatically alters the hormonal milieu to which the endometrium is exposed versus normal menstrual cycles. Endometrial maturation may be profoundly affected by this altered endocrine environment.

Aim

Compare endometrial histology in fertile women, fertile women undergoing hormonal stimulation for oocyte donation and infertile women undergoing fresh embryo transfers in an ART cycle with further comparisons between women who did or did not become pregnant. Examine the presence of leukocytes and markers of endometrial maturation.

Methods

Endometrial histology was examined by hematoxylin and eosin staining with a semi quantitative scoring method developed to compare histological appearance of tissues. The presence of leukocytes and developmental markers was examined by immunohistochemistry and scored.

Results

Endometrial histology was dramatically altered upon stimulation for ART. However, those women who became pregnant presented with significantly less alterations in histological endometrial maturation. Numbers and activation status of leukocyte populations were also altered within the endometria stimulated for ART, with neutrophils undergoing degranulation, usually observed only pre-menstrually.

Conclusion

We propose that such developmental changes render the endometrium hostile to the embryo and that modifications to ART protocols should be considered to take account of the requirement for endometrial receptivity and hence increase pregnancy rates.

Peripheral blood stem cell transplants do not result in endometrial stromal engraftment

OBJECTIVE

To determine whether peripheral blood stem cell transplant (PBSCT) result in engraftment of donor stem cells in the recipient uterus.

DESIGN

Prospective clinical and laboratory research.

SETTING

Translational medicine research hospital. PATIENT(S)/ANIMAL(S): Macaque and human bone marrow transplant recipients.

INTERVENTION(S)

Rhesus macaques received autologous transduced immunoselected cytokine-mobilized CD34+ cells after total body irradiation. Vector constructs expressed green fluorescent protein. In the human subjects, prior PBSCT subjects underwent endometrial biopsy and bone marrow aspiration. Macaque and human endometrial and bone marrow cells were isolated and cultured. Fluorescent microscopy, flow cytometry, and polymerase chain reaction (PCR) were used to evaluate for the presence of donor-derived cells.

MAIN OUTCOME MEASURE(S)

Presence of donor cells in recipient endometrium and bone marrow stroma.

RESULT(S)

The macaque endometrial cells did not exhibit evidence of green fluorescent protein labeling. Human endometrial cells were cultured and the absence of donor blood contamination was verified. The PCR evaluation of the human endometrial cells did not demonstrate evidence of donor short tandem repeats.

CONCLUSION(S)

The PBSCT did not result in engraftment of donor-derived cells in the endometrium.

Neonatal phytoestrogen exposure alters oviduct mucosal immune response to pregnancy and affects preimplantation embryo development in the mouse

Treatment of neonatal mice with the phytoestrogen genistein (50 mg/kg/day) results in complete female infertility caused in part by preimplantation embryo loss in the oviduct between Days 2 and 3 of pregnancy. We previously demonstrated that oviducts of genistein-treated mice are "posteriorized" as compared to control mouse oviducts because they express numerous genes normally restricted to posterior regions of the female reproductive tract (FRT), the cervix and vagina. We report here that neonatal genistein treatment resulted in substantial changes in oviduct expression of genes important for the FRT mucosal immune response, including immunoglobulins, antimicrobials, and chemokines. Some of the altered immune response genes were chronically altered beginning at the time of neonatal genistein treatment, indicating that these alterations were a result of the posteriorization phenotype. Other alterations in oviduct gene expression were observed only in early pregnancy, immediately after the FRT was exposed to inflammatory or antigenic stimuli from ovulation and mating. The oviduct changes affected development of the surviving embryos by increasing the rate of cleavage and decreasing the trophectoderm-to-inner cell mass cell ratio at the blastocyst stage. We conclude that both altered immune responses to pregnancy and deficits in oviduct support for preimplantation embryo development in the neonatal genistein model are likely to contribute to infertility phenotype.