Contribution of immunology to implantation failure of euploid embryos

Evaluation of the maternal systemic immune system during frozen euploid embryo transfer according to cycle outcome

Infertility affects 15 % of couples in the US, and many turn to assisted reproductive technologies, including in vitro fertilization and subsequent frozen embryo transfer (FET) to become pregnant. This study aimed to perform a broad assessment of the maternal immune system to determine if there are systemic differences on the day of FET in cycles that result in a live birth compared to those that do not. Women undergoing FET of euploid embryos were recruited and blood was collected on the day of FET as well as at early timepoints in pregnancy. Sixty immune and angiogenic proteins were measured in plasma, and gene expression of 92 immune-response related genes were evaluated in peripheral blood mononuclear cells (PBMCs). We found plasma concentrations of interleukin-13 (IL-13) and macrophage derived chemokine (MDC) were significantly lower on the day of FET in cycles that resulted in a live birth. We also found genes encoding C-C chemokine receptor type 5 (CCR5), CD8 subunit alpha (CD8A) and SMAD family member 3 (SMAD3) were upregulated in PBMCs on the day of FET in cycles that resulted in live birth. Measurements of immune mediators from maternal blood could serve as prognostic markers during FET to guide clinical decision making and further our understanding of implantation failure.

The Impacts of Inflammatory and Autoimmune Conditions on the Endometrium and Reproductive Outcomes

Background: A healthy pregnancy begins with an adequate endometrial state, even before the arrival of a blastocyst. Proper endometrial priming and the development of a tolerogenic decidua are key steps in creating the perfect environment for implantation and pregnancy. In these processes, the involvement of the maternal immune system seems to be of great relevance, modulating the different decidual immune populations to prepare the endometrium for a potential pregnancy. However, certain local pathologies of an inflammatory and autoimmune nature appear to have a direct impact on these phenomena, thus altering patients' reproductive outcomes. Methods: This literature review analyzes original articles, reviews, systematic reviews, and meta-analyses published between 1990 and 2024, concerning the impact of different inflammatory and autoimmune conditions on endometrial status and fertility. The included papers were obtained from Medline (Pubmed) and the Cochrane library. Results: There is evidence that endometriosis, adenomyosis, and chronic endometritis, through the promotion of a chronic inflammatory environment, are capable of altering endometrial immune populations, and, thus, processes essential for early pregnancy. Among other effects, these conditions have been linked to impaired decidualization, alterations in progesterone responsiveness, and hindered placentation. Similarly, antiphospholipid syndrome (APS), thyroid dysfunction, diabetes, and other pathologies related to glucose and gluten metabolism, due to their autoimmune nature, also appear to have a local impact on the uterine environment, affecting reproductive success through different mechanisms, including altered hormonal response and, again, impaired decidualization. Conclusions: The management of inflammatory and autoimmune diseases in assisted reproduction patients is gaining importance due to their direct impact on the endometrium. It is necessary to follow current expert recommendations and established therapeutic approaches in order to improve patients' prospects, ranging from antibiotic treatment in chronic endometritis to heparin and aspirin in APS, as well as hormonal treatments for endometriosis/adenomyosis or a gluten-free diet in celiac disease. All of them and the rest of the therapeutic perspectives, both current and under investigation, are presented throughout this work, assessing the possible improvements for reproductive outcomes.

Maternal-Fetal Compatibility in Recurrent Pregnancy Loss

Nowadays, recurrent pregnancy loss (RPL) is an undesirable condition suffered by many patients of reproductive age. In this scenario, certain immune cell populations and molecules, involved in maternal-fetal compatibility, have emerged as factors related with the pathogenesis of RPL. Among them, uterine Natural Killer cells (uNKs) appear to be of great relevance. These cells are involved in numerous processes during pregnancy, such as the remodeling of uterine spiral arteries or the control of trophoblast invasion. These functions are regulated by the interactions that these cells establish with the extravillous trophoblast, mainly through their Killer Immunoglobulin-like Receptors (KIRs) and the Human Leukocyte Antigen-C (HLA-C) molecules expressed by the embryo. A high level of polymorphism has been reported for both molecules involved in this interaction, with some of the possible KIR-HLA-C combinations being associated with an increased risk of RPL. However, the complexity of the maternal-fetal interface goes beyond this, as other HLA molecules also appear to be related to this reproductive pathology. In this review, we will discuss the role of uNKs in pregnancy, as well as the polymorphisms and clinical implications of KIR-HLA-C binding. We will also address the involvement of other, different HLA molecules in RPL, and the current advice on the appropriate management of patients with 'immunological mismatch', thus covering the main aspects regarding the involvement of maternal-fetal compatibility in RPL.

Exploring Natural Killer Cell Testing in Embryo Implantation and Reproductive Failure: An Overview of Techniques and Controversies

The blastocyst nidation is the most crucial stage to a successful pregnancy, as the white cells work to promote a favorable endometrial microenvironment for this process. Intriguingly, this implantation window lasts, on average, 6 days in most regular women, and its quality is affected by many pathological conditions. Since the grounds of reproductive failure in healthy couples are still uncharted, studies have widely suggested a potential hostile role of the immune system in the equilibrium of the maternal-fetal interface. In recent years, natural killer cells have been the highlight as they represent the greatest lymphocyte in the uterus and have immune surveillance through cytotoxicity during the implantation window. This review explored the main techniques used for natural killer (NK) cell testing in the implantation window over the last 13 years on the PubMed® database. Of 2167 published articles potentially relevant for the review, only thirty-three were about cell evaluation in healthy women, met the inclusion criteria, and had their methodology critically analyzed. Here, we bring a summary from the study group and sample collection to evidence comments about their findings and correlations. Meanwhile, we also summarize the current relationship between NK cells and endometrial receptivity with reproductive failure to help enhance the possibilities for future research. In conclusion, our overview points out that restricted and unstandardized methods support the controversy between the NK population and unsuccessful embryo implantation, which is an obstacle to studying why healthy eggs do not thrive and finding a solution for one of the most controversial topics in human reproduction.

The Use of Intralipid Infusions in the Prevention of Embryo Implantation Failure

Intralipids have been suggested to suppress uterine natural killer cell activity, which could potentially improve implantation rates in women with recurrent loss. We report a case of a 41-year-old African woman with recurrent pregnancy loss who had elevated uterine killer cell activity and for whom intralipid infusion was used to achieve pregnancy. We recommend routine uterine natural killer cell testing for women with recurrent pregnancy loss and further research on newer intravenous lipid emulsions in fertility medicine.

Immunological Aspects of Infertility-The Role of KIR Receptors and HLA-C Antigen

The mechanisms of immune tolerance of a mother against an antigenically foreign fetus without a concomitant loss of defense capabilities against pathogens are the factors underlying the success of a pregnancy. A significant role in human defense is played by killer immunoglobulin-like receptor (KIR) receptors, which regulate the function of the natural killer (NK) cells capable of destroying antigenically foreign cells, virus-infected cells, or tumor-lesioned cells. A special subpopulation of NK cells called uterine NK cells (uNK) is found in the uterus. Disruption of the tolerance process or overactivity of immune-competent cells can lead to immune infertility, a situation in which a woman's immune system attacks her own reproductive cells, making it impossible to conceive or maintain a pregnancy. Since the prominent role of the inflammatory response in infertility, including KIR receptors and NK cells, has been postulated, the process of antigen presentation involving major histocompatibility complex (MHC) molecules (HLA) appears to be crucial for a successful pregnancy. Proper interactions between KIR receptors on female uNK cells and HLA class I molecules, with a predominant role for HLA-C, found on the surface of germ cells, are strategically important during embryo implantation. In addition, maintaining a functional balance between activating and inhibitory KIR receptors is essential for proper placenta formation and embryo implantation in the uterus. A disruption of this balance can lead to complications during pregnancy. The discovery of links between KIR and HLA-C has provided valuable information about the complexity of maternal-fetal immune interactions that determine the success of a pregnancy. The great diversity of maternal KIR and fetal HLA-C ligands is associated with the occurrence of KIR/HLA-C combinations that are more or less favorable for reproductive success.

Immune and oxidative stress disorder in ovulation-dysfunction women revealed by single-cell transcriptome

Introduction

Ovulation dysfunction is now a widespread cause of infertility around the world. Although the impact of immune cells in human reproduction has been widely investigated, systematic understanding of the changes of the immune atlas under female ovulation remain less understood.

Methods

Here, we generated single cell transcriptomic profiles of 80,689 PBMCs in three representative statuses of ovulation dysfunction, i.e., polycystic ovary syndrome (PCOS), primary ovarian insufficiency (POI) and menopause (MENO), and identified totally 7 major cell types and 25 subsets of cells.

Results

Our study revealed distinct cluster distributions of immune cells among individuals of ovulation disorders and health. In patients with ovulation dysfunction, we observed a significant reduction in populations of naïve CD8 T cells and effector memory CD4 T cells, whereas circulating NK cells and regulatory NK cells increased.

Discussion

Our results highlight the significant contribution of cDC-mediated signaling pathways to the overall inflammatory response within ovulation disorders. Furthermore, our data demonstrated a significant upregulation of oxidative stress in patients with ovulation disorder. Overall, our study gave a deeper insight into the mechanism of PCOS, POI, and menopause, which may contribute to the better diagnosis and treatments of these ovulatory disorder.

A new method for endometrial dating using computerized virtual pathology

Endometrial dating (ED) is the process by which the menstrual cycle day is estimated and is an important tool for the evaluation of uterine status. To date, ED methods remain inaccurate and controversial. We demonstrate how the rise of computerized virtual histology changes the state of affairs and introduce a new ED method. We present the results of a clinical trial where magnified images of ex-vivo endometrial tissue samples were captured at different cycle days, together with measurements of serum hormone levels on the same day. Patient testimonies about their cycle day were also collected. Computerized image analysis, followed by statistical representation of the tissue features, allowed mathematical representation of the cycle day. The samples underwent ED histological assessment, which is currently the ED gold standard. We compared dating results from patient reports, serum hormone levels, and histology to establish their concordance level. We then compared histology-based ED with the new method ED in the secretory phase (i.e. post ovulation). The correlation coefficient between the two resulted in an R = 0.89 with a P-value of P < 10-4. The new method, Virtual Pathology Endometrial Dating (VPED), has the benefit of being a real time, in-vivo method that can be repeatedly applied without tissue damage, using a dedicated hysteroscope. One practical use of this method may be the determination of accurate real-time embryo transfer timing in IVF treatments.

Comparison of the efficacy of depot GnRH agonist protocol and the GnRH antagonist protocol in patients with repeated IVF failure: a retrospective cohort study

The aims of the research were (i) to compare the clinical outcome of IVF using follicular-phase depot gonadotropin-releasing hormone (GnRH) agonist (depot agonist) protocol and GnRH antagonist protocol in patients with repeated IVF failure (RIF), (ii) to discover the optimal ovarian stimulation protocol for this group of low prognosis patients. 801 RIF patients with normal ovarian reserve receiving in vitro fertilization/intracytoplasmic sperm injection (IVF/ICSI) were included in this retrospective study. Among them, 492 patients were treated with the depot agonist protocol, and the remaining 309 patients with the antagonist protocol. Multivariable logistic regression analysis was used to find the predictor(s) of the chance of live birth. Higher live birth rate (LBR) and clinical pregnancy rate (CPR) in fresh embryo transfer (ET) cycles were associated with the use of depot agonist compared with the antagonist protocols (44.81% vs. 27.27%, 54.64% vs. 34.93%, respectively; both p < 0.01) and depot agonist protocol was a strong predictor of live birth (OR = 2.182, 95% CI 1.355-3.514, p < 0.01). The CPR in thawed ET cycles was not significantly different between the two groups (38.12% vs. 45.26%, p > 0.05). A higher cumulative live birth rate (CLBR) was achieved in the depot agonist group (46.59% vs. 35.21%, p < 0.01). Beneficial endometrial receptivity in the depot agonist protocol contributed to a higher LBR in fresh ET cycles, rendering this protocol the preferred option in the treatment of RIF patients.

Killer Cell Immunoglobulin-like Receptor Genotypes and Reproductive Outcomes in a Group of Infertile Women: A Romanian Study

A growing body of evidence suggests that endometrial immune disorders may be responsible for endometrial dysfunctions that can lead to gynecological and obstetrical pathology. The aim of this study was to explore the potential relationship between different killer cell immunoglobulin-like receptor (KIR) genotypes and reproductive outcomes. We conducted a prospective cohort study that included 104 infertile patients undergoing an in vitro fertilization procedure. All participants underwent clinical and ultrasound examination, genetic evaluation (KIR genotyping), endometrial washing fluid sampling for cytokine determination, endometrial tissue sampling for histologic assessment and hysteroscopic evaluation. Our analysis showed statistically significant lower levels of uterine cytokines TNF-α (p = 0.001) and IL-1beta (p = 0.000) in the KIR AA genotype group as compared to KIR AB and BB among study participants with chronic endometritis. The study results suggest that the KIR AA genotype population subgroups may be more susceptible to developing endometrial disorders such as chronic endometritis. The changes in the behavior of NK cells seem to be subtle and expressed as an altered regulatory pattern.

Increased cytotoxic natural killer cells in the endometrium alone cannot be considered the immunological cause of recurrent miscarriage

OBJECTIVE

To study the distribution and gene expression of endometrial immune cell populations, especially natural killer (NK) subsets, between assisted reproductive technology patients and healthy donors and explore a possible relationship of these results with patients' killer cell immunoglobulin-like receptor (KIR) genotypes and KIR-human antigen leukocyte-C (HLA-C) binding.

DESIGN

Prospective observational cohort study.

SETTING

Clinic and university laboratories.

PATIENT(S)

Participants included 39 women with recurrent miscarriages who had undergone in vitro fertilization cycles with donated oocytes and 21 healthy oocyte donors with proven fertility.

INTERVENTION(S)

Endometrial biopsy samples were collected from both patients and donors, and the KIR genotypes of the assisted reproductive technology patients were analyzed.

MAIN OUTCOME MEASURE(S)

Endometrial gene expression (cluster of differentiation [CD] antigens and anti-inflammatory and proinflammatory interleukins) and the number and percentage of regulatory T and NK cell populations in patients and donors were determined. Subsequently, the results obtained were categorized in the group of patients by KIR genotype. Killer cell immunoglobulin-like receptor-HLA-C binding was also examined in patients, considering their KIRs.

RESULT(S)

A higher percentage of CD56dimCD16+ NK cells were observed in patients than those in healthy donors. Nevertheless, when categorizing patients by KIR genotype and comparing the KIR AA (35.9%), AB (43.6%), and BB (20.5%) groups, no statistically significant difference was observed in either endometrial gene expression or any of the immune cell populations analyzed. Finally, no differences in binding between KIR and HLA-C molecules were registered among these 3 sets of patients.

CONCLUSION(S)

The reported increase in the number of NK cells with a cytotoxic profile in the endometrium of women with a history of recurrent miscarriages cannot alone explain these events because no relationship is observed between such cellular increase and the KIR genotypes, which individually, and in combination with the different HLA-C alleles, have also been associated, by previous studies, with negative reproductive outcomes.

CLINICAL TRIAL REGISTRATION NUMBER

1405-MAD-025-JG.

Immune phenotype of the endometrium in patients with recurrent implantation failures after the transfer of genetically tested embryos in assisted reproductive technology programs

Recurrent implantation failures (RIF) in assisted reproduction programs are one of the most challenging problems. Among the factors that can adversely affect implantation, endometrial immune structural disorders may be one of the leading causes. The aim of our work was to study the immune features of the endometrium in women with RIF after genetically tested embryo transfer in comparison with fertile gestational carriers. Immune cells in endometrial samples were studied by flow cytometry and RNA expression of IL (interleukin)15, IL18, fibroblast growth factor-inducible 14 receptor (Fn14), and tumor necrosis factor-like weak inducer of apoptosis (TWEAK) by reverse polymerase chain reaction. In one-third of the cases, a unique immune profile of the endometrium, which we called the not transformed endometrial immune phenotype, was found. It is characterized by a combination of features, such as high expression of HLA-DR on natural killers (NK), increased fraction of CD16 + , and a decreased fraction of CD56bright endometrial NK. In addition, when compared to gestational carriers, patients with RIF had a greater discrepancy between IL18 mRNA expression data, reduced mean TWEAK and Fn14 levels, and increased IL18/TWEAK and IL15/Fn14 ratios. Immune abnormalities that were found in more than half of the patients (66.7 %) may be the cause of implantation failures in genetically tested embryo transfer programs.

Can endometrial thickness at baseline or maximum stimulated levels during IVF predict the presence of endometrial polyps in women with two failed embryo transfers?

PURPOSE

To evaluate whether different measurements of endometrial thickness pre-IVF cycle and during the IVF cycles as measured by transvaginal ultrasound are associated with the absence or presence of endometrial polyps.

DESIGN

A retrospective cohort study was conducted in a university-affiliated fertility center. Patients were women who underwent two embryo transfer cycles and failed to conceive.

INTERVENTIONS

hysteroscopic evaluation and resection of any masses.

RESULTS

There was no difference on comparing the groups with and without polyps in the mean endometrial thicknesses at baseline scans pre-treatment or during IVF cycle. For women who failed two embryo transfer cycles, at any given endometrial thickness the probability of the presence of a polyp was 30-40%. ROC curves failed to detect an actionable relationship with different endometrial thicknesses and the relationship with an endometrial polyp, with most areas under the curve being just above 0.5. However, once the maximum stimulated endometrial thickness was ≥ 13 mm, there was a 70% chance of a polyp being noted at hysteroscopy. This was a statistical difference in the probability of a polyp being present as compared to the lesser thicknesses (p = 0.05).

CONCLUSION

Baseline or maximum stimulated endometrial thickness at IVF fails to predict with accuracy the presence of a polyp. However, if the maximum stimulated thickness was at least 13 mm, there was a higher probability of a uterine polyp being present. Such a cutoff would nevertheless miss most polyps. At any baseline thickness on CD 2-5, a polyp has a 30-40% probability of being present in women who failed two embryo transfers. ROC curves suggest that at baseline, or maximum stimulated endometrial thickness, the ability to predict a polyp is no better than flipping a coin. As such, endometrial cavity evaluation for polyps is legitimate in women with two embryo transfers irrelevant of the baseline or stimulated thickness.

Human Leukocyte Antigen Alleles Compatibility and Immunophenotypic Profile Associations in Infertile Couples

Introduction: The maternal immune system has a major role in the successful embryo implantation and maintenance of the pregnancy. This study aimed to investigate the maternal immunophenotyping profile (percentage of Natural Killer [NK] cells and the CD4/CD8 [cluster designation] ratio in peripheral blood lymphocytes) and the HLA (Human Leukocyte Antigen)-DQA1 alleles sharing in infertile couples.

Methods: This cross-sectional study included 78 women who had experienced at least two spontaneous miscarriages and 110 women with a history of recurrent implantation failures after in vitro fertilization (IVF) or intracytoplasmic sperm injection (ICSI) and embryo transfer (ET) (IVF-ET failures). The NK cell percentage and the CD4/CD8 ratio were determined by flow cytometry. Genotyping of the HLA-DQA1 alleles was carried out for all women and their partners, and couple HLA-DQA1 compatibility was expressed as the percentage of common HLA-DQA1 alleles (totaling 35 alleles) shared between spouses to the sum of the unique alleles observed.

Results: In women with recurrent miscarriages, high values (%) of the NK population with a median (interquartile range [IQR]) of 10.3% (7.7% to 12.5%) and CD4/CD8 ratio (1.7) (1.5 to 2.1) were found. In women with IVF-ET failures, the (%) NK population (10.5%) (8.6% to 12.5%) and CD4/CD8 ratio (1.8) (1.5 to 2.1) were similarly increased (p=0.390, and p=0.490, respectively). The proportion of women with >10% NK cells was 53.8% and 58.2% in women with miscarriages and IVF-ET failures, respectively (p=0.554). The prevalence of HLA-DQA1*5 allele carriage was elevated in women with miscarriages as well as those with IVF-ET failures (52.6% and 61.8%, respectively; p=0.206). The proportion of couples with high (>50%) HLA-DQA1 sharing was 65.4% in the group with miscarriages and 73.6% in the group with IVF-ET failures, respectively (p=0.222). The CD4/CD8 ratio was statistically significantly positively correlated with the (%) NK population in women with IVF-ET failures (rho = 0.297, p=0.002) and with the (%) HLA-DQA1 sharing in the group with miscarriages (rho = 0.266, p=0.019). The couples in which both spouses were carriers of the HLA-DQA1*5 allele had an increased probability of high (>50%) HLA-DQA1 compatibility compared with the couples in which neither of the spouses carried the allele in the miscarriage group (OR = 24.3, 95% CI: 3.0 to 198.9, p<0.001), and the IVF-ET failure group (OR = 10.5, 95% CI: 2.2 to 49.8, p<0.001).

Conclusion: The peripheral NK (%) population and CD4/CD8 ratio, as well as the prevalence of the HLA-DQA1*5 allele, were elevated in women with recurrent miscarriages and IVF-ET failures. Furthermore, these couples with negative reproductive outcomes had a high percentage of HLA-DQA1 allele similarity. The presence of the HLA-DQA1*5 allele in spouses was strongly associated with overall couple HLA-DQA1 compatibility, implying that it could be used as a surrogate marker for assessing overall immunological compatibility in infertile couples.

IL-6/IL-10 and IL-1β/IL-4 ratios associated with poor ovarian response in women undergoing in-vitro fertilization

The aim of this work was to evaluate whether serum cytokines levels are associated with ovarian response in IVF. 149 patients were included in a retrospective study. Cytokines IL-2, IL-4, IL- 6, IL-8, IL-10, VEGF, IFNγ, TNFα, IL-1α, IL-1β, MCP-1 and EGF were measured by sandwich immunoassay previously to ovarian stimulation. Performing hierarchical cluster analysis, we observed that the antral follicle count, the total oocytes recovered and the MII recovered are grouped in the same cluster as the cytokines IL-2-4-6-10-1α-1β, IFNγ y TNFα. Then, we found that the ratio between IL and 6 and IL-10 was higher in low responder women (2.15 versus 1.55; p = 0.035). If we establish 0.9 as a cut-off for the IL-6/IL-10, we observed that above this value the risk of having a low response to ovarian stimulation was more than 3 times greater than below this value (22.9 % versus 6.0 %; p = 0.007). Also, the ratio IL-1β/IL-4 was higher in patients with normal or suboptimal response (0.62 versus 0.34; p = 0.034) and any patient with low response had a value greater than 0.7 (p = 0.003). As a conclusion, the IL-6/IL-10 and IL-1β/IL-4 ratios showed differences between normoresponder women and patients with low ovarian response.

Preimplantation genetic testing for aneuploidy in patients with low embryo numbers: benefit or harm?

PURPOSE

We sought to explore the utility of preimplantation genetic testing for aneuploidy (PGT-A) in a poor prognosis group of women with few embryos available for transfer.

METHODS

This was a retrospective matched cohort study examining records for first or second-cycle IVF patients with 1 to 3 blastocysts. The study group comprised 130 patients who underwent PGT-A on all embryos. The control group included 130 patients matched by age, BMI, and blastocyst number and quality who did not undergo PGT-A during the same time period.

RESULTS

The live birth rate (LBR) per embryo transfer (ET) were similar in the PGT-A and control groups, and the spontaneous abortion (SAB) rate was the same (23%). However, we found a significantly higher LBR per oocyte retrieval in the control group vs the PGT-A group (43% vs 20%, respectively) likely due to the many no-euploid cycles in the PGT-A group. In a subgroup analysis for age, the similar LBR per ET persisted in women < 38. However, in older women, there was a trend to a higher LBR per ET in the PGT-A group (43%) vs the control group (22%) but a higher LBR per oocyte retrieval in the control group (31%) vs the PGT-A group (13%).

CONCLUSIONS

Overall, we observed a significant increase in LBR per oocyte retrieval in women in the control group compared to women undergoing PGT-A, and no difference in SAB rate. Our data suggests that PGT-A has no benefit in a subpopulation of women with few embryos and may cause harm.

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

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

Proteomic alteration of endometrial tissues during secretion in polycystic ovary syndrome may affect endometrial receptivity

Embryo implantation is a complex developmental process that requires coordinated interactions among the embryo, endometrium, and the microenvironment of endometrium factors. Even though the impaired endometrial receptivity of patients with polycystic ovary syndrome (PCOS) is known, understanding of endometrial receptivity is limited. A proteomics study in three patients with PCOS and 3 fertile women was performed to understand the impaired endometrial receptivity in patients with PCOS during luteal phases. Through isobaric tags for relative and absolute quantitation (iTRAQ) analyses, we identified 232 unique proteins involved in the metabolism, inflammation, and cell adhesion molecules. Finally, our results suggested that energy metabolism can affect embryo implantation, whereas inflammation and cell adhesion molecules can affect both endometrial conversion and receptivity. Our results showed that endometrial receptive damage in patients with PCOS is not a single factor. It is caused by many proteins, pathways, systems, and abnormalities, which interact with each other and make endometrial receptive research more difficult.

Allogeneic lymphocytes immunotherapy in female infertility: Lessons learned and the road ahead

The endometrium is an essential tissue in the normal immunologic dialogue between the mother and the conceptus, which is necessary for the proper establishment and maintenance of a successful pregnancy. It's become evident that the maternal immune system plays a key role in the normal pregnancy's initiation, maintenance, and termination. In this perspective, the immune system contributes to regulating all stages of pregnancy, thus immunological dysregulation is thought to be one of the major etiologies of implantation failures. Many researchers believe that immune therapies are useful tactics for improving the live births rate in certain situations. Lymphocyte immunotherapy (LIT) is an active form of immunotherapy that, when used on the relevant subgroups of patients, has been shown in multiple trials to dramatically enhance maternal immunological balance and pregnancy outcome. The primary goal of LIT is to regulate the immune system in order to create a favorable tolerogenic immune milieu and tolerance for embryo implantation. However, there are a plethora of influential factors influencing its therapeutic benefits that merit to be addressed. The objective of our study is to discuss the mechanisms and challenges of allogeneic LIT.

The Role of Interleukins in Recurrent Implantation Failure: A Comprehensive Review of the Literature

Recurrent implantation failure (RIF) is a multifactorial condition affecting 10-15% of in vitro fertilization (IVF) couples. Data suggest that functional dysregulation of the endometrial immune system constitutes one of the main pathophysiological mechanisms leading to RIF. The aim of this article is to provide a thorough presentation and evaluation of the role of interleukins (ILs) in the pathogenesis of RIF. A comprehensive literature screening was performed summarizing current evidence. During implantation, several classes of ILs are secreted by epithelial and stromal endometrial cells, including IL-6, IL-10, IL-12, IL-15, IL-18, and the leukemia inhibitory factor. These ILs create a perplexing network that orchestrates both proliferation and maturation of uterine natural killer cells, controls the function of regulatory T and B cells inhibiting the secretion of antifetal antibodies, and supports trophoblast invasion and decidua formation. The existing data indicate associations between ILs and RIF. The extensive analysis performed herein concludes that the dysregulation of the ILs network indeed jeopardizes implantation leading to RIF. This review further proposes a mapping of future research on how to move forward from mere associations to robust molecular data that will allow an accurate profiling of ILs in turn enabling evidence-based consultancy and decision making when addressing RIF patients.

Intralipid therapy and adverse reproductive outcome: is there any evidence?

Controversy exists regarding the benefits of intravenous intralipid therapy in patients with a poor reproductive history. It is frequently reported that there is no evidence to support the effectiveness, utility or safety for this treatment. While individual studies may be perceived as weak, a systematic review and meta-analysis were performed to determine if there is any advantage to patients. PubMed, Embase and Scopus searches were performed with the target populations being either recurrent pregnancy loss (RPL), or recurrent implantation failure (RIF) undergoing assisted reproductive technology (ART) and receiving intralipid infusions. These cohorts were compared with either placebo, no intervention or alternative treatments. The most relevant outcome measures were considered to be clinical pregnancy rate (CPR), live birth rate (LBR), implantation rate (IR) and miscarriage rate (MR). Twelve studies encompassing 2676 participants met the criteria for selection and were included and reviewed. Treatment of the target population with intralipid led to an improvement in IR (Odds Ratio (OR): 2.97, 2.05–4.29), pregnancy rate (OR: 1.64, 1.31–2.04), and LBR (OR: 2.36, 1.75–3.17), with a reduction in MR (OR: 0.2, 0.14–0.30). Although intravenous intralipid is not recommended as a routine treatment for recurrent miscarriage or implantation failure, there is enough data to suggest consideration in selected patients where routine testing is unremarkable, standard treatments have failed and immunological risk factors are present. The presence of abnormal uterine natural killer (uNK) cells needs more study as a target marker to determine those who could benefit.

OUP accepted manuscript

STUDY QUESTION

Is oral Vitamin D supplementation able to modify the intrauterine milieu in terms of cytokine/chemokine pattern?

SUMMARY ANSWER

No significant differences were detected in cytokine and chemokine levels in endometrial secretions between patients undergoing ART with or without Vitamin D supplementation.

WHAT IS KNOWN ALREADY

Cytokines and chemokines secreted into the intrauterine environment are fundamental for the molecular crosstalk between the endometrium and the preimplantation embryo. Whether Vitamin D can regulate these mediators in the endometrial environment is still unclear.

STUDY DESIGN, SIZE, DURATION

This study was an analysis of a secondary outcome from the Supplementation of Vitamin D and Reproductive Outcomes—SUNDRO—clinical trial, a multicenter randomized double-blinded trial designed to explore the effects of Vitamin D replacement in women with Vitamin D levels below 30 ng/ml undergoing autologous ART cycles. Uterine fluid samples were collected from both patients supplemented with Vitamin D (n = 17) and from the placebo group (n = 32).

PARTICIPANTS/MATERIALS, SETTING, METHODS

Based on cutoff points for Vitamin D insufficiency (20–29.9 ng/ml) or deficiency (<20 ng/ml), 67% of patients in the study were insufficient, and 33% deficient, in Vitamin D, although they were considered together for the analysis. Women received a single dose of 600 000 IU 25-hydroxyvitamin D or placebo from 2 to 12 weeks before oocyte retrieval. Inclusion criteria were female age 18–39 years, with a BMI between 18 and 25 kg/m². Serum 25-hydroxyvitamin D was assessed at the time of hCG administration. Uterine fluid samples were collected during the secretory phase of the menstrual cycle preceding oocyte retrieval. The quantitative determination of 27 cytokines in endometrial secretion samples was performed by using a multiplex immunoassay.

MAIN RESULTS AND THE ROLE OF CHANCE

Uterine fluid samples were collected after a median (range) of 21 (12–41) days after the oral Vitamin D supplementation. Both the supplemented and placebo groups had Vitamin D serum levels below 30 ng/ml at baseline/time of randomization ((median 23.4 ng/ml (interquartile range 19.5–28.4) and 23.4 ng/ml (17.8–25.9), respectively). At the time of hCG administration, serum Vitamin D in supplemented subjects was significantly raised compared to the placebo group ((median 52.9 ng/ml (interquartile range 40.7–64.1) and 24.6 ng/ml (19.3–29.2), respectively, P < 0.001). Our data revealed no significant differences in uterine fluid cytokine/chemokine composition of Vitamin D-supplemented women compared with the placebo group. This finding remained when the concentrations of all mediators studied were normalized to total protein. In a further analysis, no significant differences were found in the content of cytokines/chemokines in uterine fluid from women who conceived (n = 19) compared with the nonpregnant group (n = 30).

LIMITATIONS, REASONS FOR CAUTION

Using a randomized study design (a single dose of 600 000 IU 25-hydroxyvitamin D versus placebo), we found no significant differences between groups. However, we cannot exclude that any benefit of Vitamin D supplementation may be specific for some subgroups of patients, such as those with an imbalance of T-helper 1 and T-helper 2 cell populations. The uterine secretions were collected during the menstrual cycle that preceded oocyte retrieval; therefore, it is possible the uterine fluid collection and analysis in the same cycle of the embryo transfer might have resulted in different conclusions. Moreover, the small sample size could limit the power of the study.

WIDER IMPLICATIONS OF THE FINDINGS

Our analysis of the uterine secretome profiling failed to show any significant difference in endometrial cytokine/chemokine patterns between women with oral Vitamin D supplementation and the placebo group. Vitamin D may act on the uterine environment through a different mechanism.

STUDY FUNDING/COMPETING INTEREST(S)

The study was funded by the Italian Ministry of Health following peer review in the competitive ‘Bando di Ricerca Finalizzata e Giovani Ricercatori 2013’ with reference code RF-2013-02358757. The authors declare that they have no conflict of interest.

TRIAL REGISTRATION NUMBER

EudraCT registration number: 2015-004233-27.

Histopathological evaluation of cesarean scar defect in women with cesarean scar syndrome

Purpose

To explore the histopathological findings of cesarean scar defect (CSD) and the immunological component in women with cesarean scar syndrome (CSS).

Methods

This retrospective study was conducted in a university hospital and a public hospital. A total of 63 patients with secondary infertility due to CSS who underwent laparoscopic resection of the CSD lesion were enrolled (CSS group), and 21 patients who underwent hysterectomy with a history of cesarean section were enrolled as control (non‐CSS group). We compared the differences in histopathological findings of CSD lesions by hematoxylin and eosin staining and immunohistochemistry for CD3, CD20, CD56, CD68, CD138, myeloperoxidase, and tryptase between the two groups.

Results

The frequency of presence of endometrium on the CSD surface was significantly lower (p = 0.0023) and that of adenomyosis was significantly higher (p = 0.0195) in the CSS group than in the non‐CSS group. The number of CD3‐, CD20‐, CD68‐, and tryptase‐positive cells was significantly lower in the CSS group than in the non‐CSS group; however, the number of CD138‐positive cells was significantly higher in the CSS group (p = 0.0042).

Conclusions

This study suggested that the absence of endometrium, presence of adenomyosis, and chronic inflammation in CSD contributes to secondary infertility due to CSS.

Intrauterine administration of peripheral blood mononuclear cells (PBMCs) improves embryo implantation in mice by regulating local Treg/Th17 cell balance

Immune imbalance of Treg/Th17 cells may contribute to recurrent implantation failure (RIF) during in vitro fertilization and embryo transfer (IVF-ET). In this study, we sought to determine the effect of intrauterine administration of mouse PBMCs prior to embryo implantation on endometrial receptivity and embryo implantation, and examine the underlying mechanism of Treg/Th17 cell balance following intrauterine administration of PBMCs. Pregnant mice were randomly divided into three groups: control group, embryo implantation dysfunction (EID) group, and EID with PBMCs group, and the number of embryo implantation sites was recorded during early pregnancy (Pd7.5). The balance of Treg/Th17 cells in the peripheral blood, spleen, and local implantation sites was detected during the peri-implantation period (Pd4.0) and early pregnancy (Pd7.5). The EID group demonstrated a significant decrease in the number of embryo implantation sites, while the EID with PBMCs group demonstrated higher number of embryo implantation sites compared to the EID group. The balance of Treg/Th17 cells in the peripheral blood and spleen tissues was not significantly different between the aforementioned groups. However, the local uterine ratio of the Treg/Th17 cells increased in the EID with PBMCs group compared to that in the EID group. Collectively, we found that intrauterine administration of PBMCs prior to embryo implantation effectively promotes embryo implantation rates. This may be attributed to the improvement in the local immune balance of Treg and Th17 cells compared with the overall immune balance.

Intrauterine administration of activated peripheral blood mononuclear cells in intrauterine insemination: a prospective double-blind randomized clinical trial

OBJECTIVE

To evaluate the effect of intrauterine administration of activated peripheral blood mononuclear cells (PBMC) on intrauterine insemination (IUI) success rates.

METHODS

This prospective double-blind randomized parallel clinical trial included 213 patients undergoing IUI at the Fertilys clinic. PBMC were isolated on the day of ovulation (day 0; D0) and stimulated with phytohemagglutinin (PHA) and human chorionic gonadotropin (hCG) for 48 hours (day 2; D2). Patients in the PBMC group (n = 108) underwent in utero administration of 1.10⁶ cells on D2, while patients in the control group (n = 105) were administered sperm-washing medium. Distribution of CD4 T lymphocyte populations (n = 61) was assessed on D0 and D2. Pregnancy and live birth rates were also evaluated.

RESULTS

Demographic and clinical characteristics, pregnancy rates, and live birth rates were not significantly different between the PBMC and control groups. Significantly higher levels of T helper (Th) 2, Th22, and T regulatory cells (P < 0.0001) and lower levels of Th17 cells were observed in hCG-activated PBMC at D2 than at D0.

CONCLUSION

Intrauterine administration of PBMC was not beneficial in IUI patients. New clinical approaches to better identify patients requiring endometrium immunomodulation needs to be addressed.

The identification of endometrial immune cell densities and clustering analysis in the mid-luteal phase as predictor for pregnancy outcomes after IVF-ET treatment

Changes in endometrial immune cell density has been reported to be associated with reproductive failure. The prognostic value of endometrial immune cell density measurement remains uncertain. We aimed to investigate the prognostic value of endometrial immune cells measurement on pregnancy outcome after IVF in women. In this prospective study, one hundred twenty-eight women underwent endometrial sampling in a natural cycle preceding single frozen-thawed embryo transfer (ET). Endometrial biopsy was obtained precisely 7 days after luteinizing hormone surge (LH + 7). Multiplex immunohistochemical method was employed to simultaneously stain the endometrium samples with a panel of human antibodies against CD56 for uterine natural killer (uNK) cells, CD3 and CD8 for T cell, CD3 for pan T cells and CD68 for macrophages. The density of the various immune cells and the clustering levels between them were measured. ET was performed at the blastocyst stage. Women who did not conceive had a significantly higher density of uNK cells and higher clustering level between uNK cells-and-macrophages than women who did conceive. In accordance, the prognostic value of uNK measurement on pregnancy outcome was significantly improved when combined with uNK-to-macrophage clustering analysis simultaneously. Taken together, our results suggested that uNK cells density and clustering level between uNK cells-and macrophages may be a promising predictor for successful implantation after IVF-ET.

Progesterone-induced blocking factor-mediated Th1/Th2 balance correlates with fetal arrest in women who underwent in vitro fertilization and embryo transfer

The role of progesterone-induced blocking factor (PIBF)-mediated Th1/Th2 balance in delivery outcomes of in vitro fertilization and embryo transfer (IVF-ET) has not been fully elucidated. In this study, 73 infertile women with successful IVF-ET were enrolled (16 fetal arrests and 57 live births). PIBF and IL-4 levels were significantly lower in the fetal arrest group than in the live birth group (p < 0.05). TNF-α level and Th1/Th2 ratios were significantly higher in the fetal arrest group than in the live birth group (p < 0.05). High TNF-α level and Th1/Th2 ratios were risk factors for fetal arrest, whereas increased PIBF and IL-4 levels were protective factors (P < 0.05). Increased TNF-α/IL-4 exhibited relatively strong predictive value for fetal arrest (AUC, 0.855; sensitivity, 93.8%; specificity, 71.9%). In summary, the PIBF-mediated Th1/Th2 balance is closely correlated with delivery outcomes of IVF-ET. TNF-α/IL-4 may be a predictive marker of fetal arrest.

CD19 and intraglandular CD163-positivity as prognostic indicators of pregnancy outcome in CD138-negative women with a previous fresh-embryo-transfer failure

Many factors impede embryonic implantation, and excluding obvious known factors such as chronic endometritis, the immune status of the endometrium may be related to pregnancy. Although an abundantly large number of immune cells infiltrate the endometrium during the secretory phase, whether these immune cells can be used as a predictor of prognosis in ART has not yet been clarified. In the present study we therefore retrospectively analyzed 97 CD138-negative women with a previous fresh-embryo-transfer failure. We assessed the expression of CD56+ uNK cells, CD16+ NK cells, CD57+ NK cells, CD68+ pan-macrophages, CD163+ M2 macrophages, CD4+T cells, CD8+T cells, FOXP3+ regulatory T cells, and CD19+ B cells in the endometrium by IHC to evaluate mid-luteal endometrial immune cells as prognostic indicators of pregnancy outcome in the next frozen-embryo-transfer cycle. CD19-positive cells and the intraglandular CD163-positivity rate increased significantly in the clinically non-pregnant group (0.47 % vs. 0.20 %, P =  0.021; 61 % vs. 30 %, P =  0.017). The ratios of CD4/CD8 were also higher in the non-pregnant group (1.96 vs. 1.45, P =  0.005).The area under the ROC curve of CD19 cell number alone, the intraglandular CD163-positivity alone, and CD19 number combined with the intraglandular CD163-positivity were 0.692 (95 % CI, 0.55-0.834), 0.661 (95 % CI, 0.514-0.809), and 0.748 (95 % CI, 0.614-0.882), respectively. The optimal cut-off value of CD19 was 0.464 %, and the clinical pregnancy rate and live-birth rate diminished significantly when the CD19 level was above this cut-off value. Our study suggests that CD19-positive cells and intraglandular CD163-positivity can be used as prognostic indicators of pregnancy outcome in CD138-negative patients who experienced first-fresh-embryo transfer failure.

Determining diagnostic criteria and cause of recurrent implantation failure

PURPOSE OF REVIEW

Recurrent implantation failure (RIF) refers to the absence of implantation after repeated transfer of good embryos into a normal uterus. This review discusses the diagnostic criteria and cause of RIF.

RECENT FINDINGS

Regardless of the advancements in IVF practice, RIF is still a challenge that has to be solved. Exact definition of RIF is lacking today. For the initial evaluation, a rigorous algorithmic evaluation should be compromised with an individualized principle. Factors that might affect the number and quality of the oocyte and sperm cells should be investigated in order to obtain a good-quality embryo. Embryo assessment should be performed under ideal laboratory circumstances. The uterine environment should be carefully evaluated and the embryo should be transferred into the uterus at the most receptive time. Some of the newly introduced diseases and empirical treatment strategies, such as chronic endometritis, vaginal microbiota, immunologic profile and immunomodulator treatments, can be discussed with the couple under the light of adequate evidence-based information.

SUMMARY

New diagnostic and treatment modalities are needed to be introduced, which would be safe, efficient and efficacious after well-designed randomized controlled trials.

Immunologic causes and thrombophilia in recurrent pregnancy loss

Certain miscarriages result from immunologic factors, but there is no clear identification of the precise causes of recurrent pregnancy loss (RPL). Miscarriages and RPL can arise from a disruption of maternal-fetal immune homeostasis. Remodeling of the maternal uterine spiral arteries is one of the key steps for normal growth and development of the fetus. An adequate oxygen supply is necessary for correct placentation, and it is accomplished by proper vascular changes. The development of fetal tissues creates a potential immunologic problem since the fetus can express paternal antigens and, in some cases, antigens of a gamete donor. The maternal immune system actively responds to fetal antigens, and dysregulation of this crosstalk could partly explain pregnancy complications such as miscarriages and RPL. RPL resulting from thrombophilia is primarily due to acquired thrombophilia, and therefore screening and treatment should be focused on antiphospholipid antibody syndrome.

Endometrial preparation with etanercept increased embryo implantation and live birth rates in women suffering from recurrent implantation failure during IVF

Recurrent implantation failure (RIF),  defined as ≥3 failed in vitro fertilization (IVF) cycles with the accumulated transfer of at least five embryos, plague many infertile women. The exact cause is unknown; however, evidence supports the immune system, specifically the Tumor Necrosis Factor (TNF) pathway. Etanercept (a TNFα antagonist) has been shown to improve pregnancy rates in women with rheumatoid arthritis or endometriomas; therefore, this study aimed to determine the effectiveness of etanercept for IVF in RIF women. Eighty-three RIF women were recruited from the Ingenes Institute in Mexico City for this single-arm, prospective study. All patients underwent a similar IVF protocol and received etanercept (4 × 25 mg every 72 h) after endometrial preparation, if applicable, and at embryo transfer. IVF endpoints assessed were embryo implantation (h-βCG >10 mg/dL at Day 14), the presence of a gestational sac, live birth, and birth weight. All women reported no side-effects associated with the etanercept treatment. 75.9 % of the cohort achieved embryo implantation, 74.7 % developed gestational sacs, and the ongoing pregnancy/live birth rate was at 62.7 %. However, 56.7 % of the live births were preterm (<37 weeks) and 60.5 % of the births were underweight (<2500 g). When stratified by fresh or frozen cycles or by the ova source (patient versus donor), the results were not significantly different with respect to the implantation rate, formation of gestational sacs, and the live birth rate. Here, we showed that using etanercept during endometrial preparation improves IVF outcomes in RIF women.

Endometrial receptivity and embryo implantation in carnivores-commonalities and differences with other mammalian species

Endometrial receptivity and embryo implantation processes are a major point of pregnancy failure in many mammalian species, including humans. Although reproductive biology in many carnivore species remains enigmatic, the few that have been studied so far are invaluable comparative models. The goals of this review are to (1) summarize current data on the mechanisms involved in uterine receptivity and embryo implantation in carnivores, including commonalities and differences with other mammalian species and (2) identify research priorities to better understand a key phenomenon in a critical group of mammals. Besides unique reproductive traits in some carnivores (induced vs. spontaneous ovulation in cats, ovulation at the germinal vesicle stage in dogs), preimplantation embryo development is comparable with other orders. However, the timing of implantation varies, especially in species having an embryonic diapause. Mechanisms involved in endometrial receptivity and decidualization still remain to be fully understood, but specific markers have already been identified. Importantly, the use of endogenous hormones to control the ovarian activity may impact endometrial receptivity and subsequent embryo implantation. Next, research efforts should take advantage of advanced technologies to further study embryo implantation in carnivores and to provide more relevant models to reproductive medicine or for the conservation of rare and endangered species.

Human Chorionic Gonadotrophin (hCG) Trigger-Mediated Ovulation Induction in Infertility Management in South Indian Women Undergoing IVF/ICSI Regimens: A Pilot Sexual Medicine Study with Public Health Perspective

Introduction:

Infertility is a global public health problem; cost-effective patient-friendly treatment modalities along with psychosexual intervention strategies are essential for infertility control/prevention/management among ethnically disparate populations.

Objectives:

This study aimed to assess differential in vitro fertilization (IVF) success trends among infertile women of South Indian ethnicity.

Materials and Methods:

Prospective, observational study designed in a hospital-based setting with active enrollment of infertile women undergoing IVF/intracytoplasmic sperm injection (ICSI) at Indira IVF Center, Chennai, Tamil Nadu, India (April-September 2019); inclusion criteria: age >35 years, South Indian ethnicity, married >1 year, absence of full-term clinical pregnancy, endometrial thickness <6 mm/thin endometrium; exclusion criteria: prior ≥2 IVF failures, fibroids/adenomyosis/cervical cancer/endometriosis. IVF success was determined by evaluating total frozen embryos transferred/month, average oocyte yield/donor, oocyte quality, M-II oocytes, biochemical/clinical pregnancy (beta-human chorionic gonadotropin positivity/fetal cardiac activity). Mycobacterium tuberculosis positivity was assessed by GeneXpert polymerase chain reaction-based technology, and psychosexual intervention-incorporated marital relationship counseling sessions/therapy, referrals for psychiatric assessments (cognitive impairment/schizophrenia/depression). Written informed consent of participants was taken and study was approved by Institutional Review Board.

Results:

Mean age and endometrial thickness of study participants were 33.3 years (SD ±1.9) and 8.7 mm (SD ±0.5), respectively; average Body Mass Index (BMI) and anti-müllerian hormone (AMH) levels were 28.4 kg/m2 and 4.7 ng/mL, respectively. Embryos transferred/month: 7 in April/13 in May/24 in June/36 in July/24 in August/30 in September, and pregnancies: 4/8/17/26/20/22 for the months of April, May, June, July, August, and September 2019, respectively. Subgroup stratification demonstrated M-II vs total oocytes retrieved were 76%, 73%, 60%, 71%, 77%, and 77%. Overall IVF success rates were 57% in April/62% in May/71% in June/72% in July/83% in August/73% in September; frozen embryo transfer success was 0 in April-May/67% in June/73% in July/89% in August/100% in September 2019. English/Tamil-speaking infertile women self-reported treatment-related satisfaction rates of 80% to 100%.

Conclusion:

M-II oocytes’ yield, sociodemographics of infertile women, and increasing age/aberrant AMH/BMI profiles/endometrial receptivity/diminished ovarian reserve are promising predictors of IVF/ICSI success in genetically distinct patient population subset(s). Future multicentric gene epidemiology studies with larger sample size and precision-based psychiatric assessments/interventions are warranted for development of predictive biomarkers in infertility management.

The Roles of Matrix Metalloproteinases and Their Inhibitors in Human Diseases

Matrix metalloproteinases (MMPs) are a family of zinc-dependent extracellular matrix (ECM) remodeling endopeptidases that have the capacity to degrade almost every component of the ECM. The degradation of the ECM is of great importance, since it is related to embryonic development and angiogenesis. It is also involved in cell repair and the remodeling of tissues. When the expression of MMPs is altered, it can generate the abnormal degradation of the ECM. This is the initial cause of the development of chronic degenerative diseases and vascular complications generated by diabetes. In addition, this process has an association with neurodegeneration and cancer progression. Within the ECM, the tissue inhibitors of MMPs (TIMPs) inhibit the proteolytic activity of MMPs. TIMPs are important regulators of ECM turnover, tissue remodeling, and cellular behavior. Therefore, TIMPs (similar to MMPs) modulate angiogenesis, cell proliferation, and apoptosis. An interruption in the balance between MMPs and TIMPs has been implicated in the pathophysiology and progression of several diseases. This review focuses on the participation of both MMPs (e.g., MMP-2 and MMP-9) and TIMPs (e.g., TIMP-1 and TIMP-3) in physiological processes and on how their abnormal regulation is associated with human diseases. The inclusion of current strategies and mechanisms of MMP inhibition in the development of new therapies targeting MMPs was also considered.

Live birth rate from euploid blastocysts is not associated with infertility etiology or oocyte source following frozen-thawed embryo transfer (FET): analysis of 4148 cycles reported to SART CORS

PURPOSE

To investigate whether live birth rates from euploid blastocyst frozen-thawed embryo transfer (FET) cycles are associated with infertility diagnosis or oocyte source.

DESIGN

Retrospective analysis of FET cycles reported to SART CORS in 2014.

METHODS

Data from fresh IVF cycles with preimplantation genetic testing for aneuploidy (PGT-A), linked to the first FET cycles, were collected from the 2014 SART CORS database for autologous and donor oocyte cycles. Inclusion criteria were patients undergoing FET with euploid embryos (n = 4148). Demographic data including age, BMI, prior fertility, and etiology of infertility were collected from the retrieval cycle and analyzed. Patients with uterine anomalies, preimplantation genetic testing-mutation (PGT-M) for genetic diseases, gender selection, HLA determination, or systemic and immunologic disorders were excluded. The primary outcome measure was live birth (LB) rate. Potential confounders such as age, prior fertility, and maximum baseline FSH values were analyzed with regression models as indicated.

RESULTS

Though age, maximum baseline FSH, and infertility diagnosis were significantly different, LB was similar between patients undergoing autologous or donor oocyte FET cycles. Etiology of infertility was not significantly associated with LB in autologous cycles (p = 0.95). Potential confounders such as maternal age, prior fertility, and maximum baseline FSH were not associated with outcomes; however, maternal BMI was inversely related to LB in autologous cycles, with an odds ratio of 0.97 (95% CI: 0.96-0.98 (rho = - 0.08, p < 0.01)).

CONCLUSIONS

After controlling for confounding variables, a euploid embryo derived from a donor or autologous oocyte results in similar LB in women with different infertility diagnoses.

Family history of autoimmune disease in relation to time-to-pregnancy, pregnancy loss, and live birth rate

Several autoimmune conditions have adverse effects on reproductive outcomes, but the relationship between family history of autoimmune disease in women without these conditions and pregnancy is uncertain. The objective of this study was to determine if there is an association between a family history of an autoimmune condition and time-to-pregnancy (TTP), pregnancy loss, and live birth. This was a prospective cohort study from a RCT of 1228 adult women ages 18-40, who were healthy, had no history of infertility, were actively attempting to conceive, and had one or two prior pregnancy losses. Of these, 1172 women had data available regarding family history of autoimmune conditions. Women with an affected first-degree relative had similar TTP when compared to those without a FHx (fecundability odds ratio 0.90, 95% confidence interval [CI] 0.70, 1.15). Women with an affected first-degree relative had a lower likelihood of live birth (relative risk [RR] 0.83, 95% CI 0.69, 0.99). Among women who achieved pregnancy, FHx of autoimmune disease was associated with a higher likelihood of pregnancy loss (RR 1.49, 95% CI 1.10, 2.03). Women who had a first-degree relative with an autoimmune disease had a similar TTP as unaffected women but a lower likelihood of live birth and higher risk of pregnancy loss. This information may encourage clinicians to evaluate women with a family history of autoimmune conditions prior to pregnancy and highlights the need for further studies to ascertain the effects of autoimmunity and pregnancy.

Parental human leukocyte antigen-C allotypes are predictive of live birth rate and risk of poor placentation in assisted reproductive treatment

OBJECTIVE

To study the pregnancy, miscarriages, and live birth rates (LBRs) according to maternal killer cell immunoglobulin-like receptor (KIR) genes expressed by uterine natural killer cells and paternal or oocyte donor human leukocyte antigen-C (HLA-C) genes expressed by trophoblast cells in patients with recurrent reproductive failure.

DESIGN

Prospective observational cohort study.

SETTING

Private infertility center.

PATIENT(S)

Participants included 204 women with recurrent miscarriage or recurrent implantation failure.

INTERVENTION(S)

The KIR and HLA-C genotypes of all women and HLA-C of their partners, gamete donors, miscarriage tissue, and babies were analyzed.

MAIN OUTCOME MEASURE(S)

All clinical variables (pregnancy, miscarriage, and LBRs) were analyzed and categorized based on KIR, oocyte origin, and single embryo transfer (SET)/double embryo transfer (DET).

RESULT(S)

A higher miscarriage rate was observed after DETs in KIR AA mothers (47.8% egg donation and 37.5% in vitro fertilization [IVF]) compared with KIR AB (10.5% egg donation and 12.5% IVF) or KIR BB (6.7% egg donation and 0% IVF). A significantly decreased LBR was observed after DETs with oocyte donation in KIR AA patients (4.3%) compared with KIR AB (26.3%) or BB (46.7%). The LBR decreased significantly as the fetal HLA-C2 load increased in KIR AA women.

CONCLUSION(S)

Elective SET improves the reproductive outcomes compared with DET. An increased embryo HLA-C2 load has a negative impact on the LBR in KIR AA patients. The selection of HLA-C1 over HLA-C2 donors could have a positive impact on the LBR in KIR AA patients.

CLINICAL TRIAL REGISTRATION NUMBER

NCT04052438.

Adipose tissue-derived regenerative cells improve implantation of fertilized eggs in thin endometrium

Aim: Embryo implantation and subsequent pregnancy depends on endometrial thickness. To investigate potential fertility strategies for women with thin endometrium, we explored the efficacy of adipose tissue-derived regenerative cells (ADRCs) on thin endometrium and embryo implantation in a mouse model. Materials & methods: ADRCs isolated from mouse subcutaneous fat were characterized by flow cytometry. Endometrium thickness, endometrial fibrosis, embryo implantation and angiogenesis factors were evaluated in uterine cavities of ethanol-induced thin endometrium mice with ADRC transplantation. Results: ADRCs included adipose-derived stem cells and some blood vessel component cells. ADRCs improved endometrial thickness, endometrial fibrosis and embryo implantation and augmented vascular endothelial growth factor expression in the mouse uterine. Conclusion: ADRCs may be a useful therapeutic strategy to improve fertility of women with thin endometrium.

The Role of Analysis of NK Cell Subsets in Peripheral Blood and Uterine Lavage Samples in Evaluation of Patients with Recurrent Implantation Failure

OBJECTIVE

In this study, we aimed to determine the role of analyses of NK cell subsets in peripheral blood and uterine lavage samples in evaluation of patients with unexplained RIF.

METHODS

This retrospective single-institution case-control study included two different cohorts between 2017-2019. First cohort included patients examined with peripheral blood samples for evaluation of possible immunologic problems in patients with unexplained recurrent implantation failure; in the study period, a total of 75 consecutive patients with RIF (study group; n: 42) or infertile patients without RIF (control group; n: 33) were included. Second cohort included those patients whose uterine samples were assessed for immunologic problems; RIF (study group ; n: 16) or infertile patients without RIF (control group; n: 25).

RESULTS

In the first cohort, the percentage of NK cells (CD3-CD16⁺56⁺) is statistically significantly lower (9.8 vs. 12.6, respectively, p: 0.038) in the study group than those of the controls whereas there was no statistical significance in the absolute number of NK cells (CD3-CD16⁺56⁺). In the second cohort, the only remarkable finding in uterine lavage samples was significantly increased uNKs cells (CD3-CD16^dim56^bright) percentages in controls (9.95 vs 12.7, respectively, p: 0.026) compared to those of study group.

CONCLUSION

Our data shows that the analysis of NK cell subtypes in peripheral blood does not seem appropriate to investigate the patients with RIF and we suggest that uterine lavage samples instead of peripheral blood samples be implemented and evaluated.

Intrauterine perfusion immunotherapies in recurrent implantation failures: Systematic review

Studies have investigated the gestational outcomes of new immunological therapies in the treatment of patients with recurrent implantation failure (RIF) in assisted reproductive technology (ART). The objective of this article is to assess the current state of evidence available in the literature on intrauterine perfusion immunotherapies in women undergoing ART treatments. By considering the guidelines of Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA), the authors performed systematic review by searching the databases of PubMed/MEDLINE and Scopus using the following key words: "recurrent implantation failure," "intrauterine infusion," "Platelet-Rich Plasma (PRP)," "Peripheral Blood Mononuclear Cells (PBMC)," "Granulocyte Colony-Stimulating Factor (G-CSF)," and "Human Chorionic Gonadotropin (hCG)." The authors analyzed the indications and the impact of new immunological therapies with intrauterine infusions on the pregnancy outcomes of patients undergoing ART. PRP, PBMC, G-CSF, and hCG were the four most used immunological therapies with intrauterine infusion. These new therapies appear to improve the results of ART treatments in cases of RIF. However, the small number of studies does not allow definitive conclusions about the effectiveness of these therapies.

Potential impact of maternal vitamin D status on peripheral blood and endometrium cellular immunity in women with recurrent implantation failure

PROBLEM

This study aims to evaluate the modulatory effects of vitamin D on peripheral blood and endometrial cellular immunity in women with recurrent implantation failure (RIF).

METHOD OF STUDY

One hundred and fifty-four women with RIF were identified at a fertility center from January 2018 and March 2019. Blood and endometrium samples were collected during the mid-luteal phase before IVF treatment or pregnancy. The serum vitamin D status, NK cell cytotoxicity, Th1 cytokine production, and endometrial immune cells were detected before and after vitamin D supplementation.

RESULTS

The NK cell cytotoxicity at an effector:target (E:T) ratio of 50:1 or 25:1 was significantly higher in vitamin D insufficiency group (VDI) than those in vitamin D normal group (VDN) (P < .05 each). The percentage of IFN-γ- or TNF-α-producing Th cells was significantly increased in VDI or vitamin D deficiency group (VDD) when compared with VDN (P < .05 each). The percentage of CD68⁺ macrophages on all endometrial cells in VDI and VDD was significantly higher than in VDN (P < .05 each), while no significant differences in the percentage of other endometrial immune cells among the three groups were observed. This dysregulation was significantly reduced with vitamin D supplementation.

CONCLUSION

Our findings highlighted that vitamin D may have an important role in the regulation of not only systemic but also local immune response for optimization of maternal tolerance for implantation in women with RIF. Pre-conception optimization of vitamin D status should be considered in women with RIF.

Intralipid Immunotherapy for Repeated IVF Failure

The intravenous fat emulsion, intralipid, has been hypothesised to be an effective and safe treatment for repeated in vitro fertilisation (IVF), implantation failure and pregnancy loss. This exploratory, retrospective cohort study determined pregnancy outcomes and documented adverse events associated with intralipid use. Ninety-three women were identified as having received intralipid for a history of repeated unsuccessful IVF cycles and pre-viable pregnancy loss in two Australian IVF units that independently recruited between October 2014 and July 2016. Pregnancy outcomes and adverse events were recorded in fresh and frozen embryo transfer cycles in which the infusion was administered. The 93 women who received intralipid had a clinical pregnancy rate of 40.0%, compared with 35.0% in 651 age-matched controls undergoing IVF, which was not significantly different. The intralipid group had a livebirth rate of 35.7%. Apart from flushing, which was experienced by one individual, there were no adverse events associated with intralipid use. As a prelude to definitive evidence of benefit, we did not identify a safety concern or reduced pregnancy rates in intralipid users compared to controls. Indeed, these outcomes were better than expected in a poor prognosis group. This data supports an argument for large, randomised controlled trials to determine the benefit of intralipid in the treatment of recurrent implantation failure or miscarriage.

The role of IL-10-producing B cells in repeated implantation failure patients with cellular immune abnormalities

There are a few data of the role of B cells in RIF pathogenesis. Accordingly, the objective of the current study was to determine the role of IL-10-producing B cells in RIF. Twenty-three RIF women with cellular immune abnormalities and 25 normal controls were enrolled in this experiment. Isolated naïve B cells from peripheral blood of the subjects were cultured in vitro, divided into two parts and activated by CpG ODN and imiquimod as TLR agonists. Afterwards, the number of CD19⁺ IL-10⁺ B cells was evaluated by flow cytometry and their related IL-10 cytokine level was assessed by ELISA. The mRNA expression levels of related genes in just CPG stimulated B cell population were also analyzed using real-time PCR. RIF patients exhibited a decreased level of the cells (P = 0.014, P = 0.023, respectively) and IL-10 cytokine (P = 0.009, P = 0.045, respectively) in both CPG and imiquimod stimulated B cell groups. IL-10 serum level was also lower in these patients (P = 0.0014). Additionally, we found a negative relationship between the frequency of these cells with the number of failed ET and total IgG titers in RIF patients. The mRNA levels of IL-10-producing B cells related genes (IL-10 and PD-L1) was also significantly lower in RIF women, whereas the expression of plasma cells-associated transcriptional factors (BLIMP1, IRF4, and XBP1) was higher. Summing up the obtained results, we concluded that peripheral blood IL-10-producing B cells down-regulation might result in RIF pathogenesis. It is further suggested that these cells can suppress autoantibody generation and contribute to a successful implantation.

Mediator in the Embryo-endometrium Cross-talk: Granulocyte Colony-stimulating Factor in Infertility

Successful implantation requires a receptive endometrium and a good quality egg. The challenges a physician encounters with regard to this in assisted reproductive technology are obtaining good quality embryo, achieving optimal endometrial thickness (EMT), and subsequently implantation, which is denotive of a receptive endometrium. Granulocyte colony-stimulating factor (G-CSF) has been observed to be a biomarker of oocyte quality and has been shown to enhance EMT and implantation because of its immunological effects. A systematic search for all relevant articles on G-CSF in follicular fluid and its therapeutic benefit in thin endometrium and recurrent implantation failure was performed, and peer-reviewed, full-text articles related to humans were included in the study. As a tool to determine the potentiality of oocyte, G-CSF shows promise with its predictability increasing in combination with morphological embryo scoring or interleukin 15. For the thin endometrium, G-CSF is especially useful in patients who are refractory to other treatment modalities. In recurrent implantation failure (RIF), G-CSF showed potential in a subset of patients with immunological deficiency lacking killer cell immunoglobulin-like receptor genes. This review highlights the various forms of usage of G-CSF and the effectiveness of G-CSF in infertility. G-CSF equips embryologists with a tool to determine the potentiality of oocyte and physicians with therapy for thin endometrium and RIF, especially since the available treatment options are ineffective.

Endometrium immunomodulation by intrauterine insemination administration of treated peripheral blood mononuclear cell prior frozen/thawed embryos in patients with repeated implantation failure

In assisted reproductive technology (ART) programmes, approximately 10% of infertile patients have at least two or three repeated implantation failures (RIFs) after an in vitro fertilization (IVF) protocol. Successful implantation mainly depends on local immune tolerance mechanisms involving a spectrum of cytokines, interleukins and growth factors. The latter have played pivotal roles in the recruitment of immune cells (and notably T-lymphocyte cells). In total, 250 couples participating in frozen-thawed embryo transfer programme were incorporated in a randomized clinical trial (peripheral blood mononuclear cells (PBMC) subgroup: n=122; control subgroup: n=128). In the PBMC group, a blood sample was collected 5 days before the scheduled frozen-thawed embryo transfer; PBMCs were isolated using Ficoll separation and then cultured for 72 h. Two days prior to embryo transfer, 0.4 ml of cultured PBMCs were transferred into the patient's uterus. Although the clinical pregnancy rate was higher in the PBMC group (34.4%) than in the control group (23.4%), this difference was not statistically significant (P=0.05 in a chi-squared test). Nevertheless, when we limited the analysis to patients with ≥3 RIFs (n=138), there was a significant difference in the clinical pregnancy rate between the PBMC group (38.6%) and the control group (19.7%; P=0.01). Our results imply that PBMC transfer can be part of effective fertility treatment for patients with RIF.

The Role of Epigenetics in Placental Development and the Etiology of Preeclampsia

In this review, we comprehensively present the function of epigenetic regulations in normal placental development as well as in a prominent disease of placental origin, preeclampsia (PE). We describe current progress concerning the impact of DNA methylation, non-coding RNA (with a special emphasis on long non-coding RNA (lncRNA) and microRNA (miRNA)) and more marginally histone post-translational modifications, in the processes leading to normal and abnormal placental function. We also explore the potential use of epigenetic marks circulating in the maternal blood flow as putative biomarkers able to prognosticate the onset of PE, as well as classifying it according to its severity. The correlation between epigenetic marks and impacts on gene expression is systematically evaluated for the different epigenetic marks analyzed.

Genetics and Epigenetics of Infertility and Treatments on Outcomes

CONTEXT

Infertility affects 10% of the reproductive-age population. Even the most successful treatments such as assisted reproductive technologies still result in failed implantation. In addition, adverse pregnancy outcomes associated with infertility have been attributed to these fertility treatments owing to the presumed epigenetic modifications of in vitro fertilization and in vitro embryo development. However, the diagnosis of infertility has been associated with adverse outcomes, and the etiologies leading to infertility have been associated with adverse pregnancy and long-term outcomes.

EVIDENCE ACQUISITION

We have comprehensively summarized the data available through observational, experimental, cohort, and randomized studies to better define the effect of the underlying infertility diagnosis vs the epigenetics of infertility treatments on treatment success and overall outcomes.

EVIDENCE SYNTHESIS

Most female infertility results from polycystic ovary syndrome, endometriosis, and unexplained infertility, with some cases resulting from a polycystic ovary syndrome phenotype or underlying endometriosis. In addition to failed implantation, defective implantation can lead to problems with placentation that leads to adverse pregnancy outcomes, affecting both mother and fetus.

CONCLUSION

Current research, although limited, has suggested that genetics and epigenetics of infertility diagnosis affects disease and overall outcomes. In addition, other fertility treatments, which also lead to adverse outcomes, are aiding in the identification of factors, including the supraphysiologic hormonal environment, that might affect the overall success and healthy outcomes for mother and child. Further studies, including genome-wide association studies, epigenomics studies, and experimental studies, are needed to better identify the factors leading to these outcomes.

Cytometric assessment of uterine receptivity via epithelial β3 integrin expression

RESEARCH QUESTION

Many techniques now exist to assess the receptivity status of the endometrium. Can a simple low-cost flow cytometric technique be used to rapidly assess uterine receptivity via a luteal phase endometrial biopsy?

DESIGN

Epithelial β3 integrin (EB3) evaluation was undertaken in 300 women presenting with repeated implantation failure or recurrent pregnancy loss who subsequently underwent 710 assisted reproductive technology (ART) cycles. Endometrial tissue was mechanically dissociated and evaluated using specific antibodies to capture integrin expression. Autologous and donor oocyte embryo transfers were evaluated. A 'High', 'Borderline' and 'Low' grading system was developed based on the pattern and percentage expression of EB3 relative to the total endometrial epithelium. Clinical outcomes of the resulting embryo transfers (n = 559) were analysed according to EB3 grading.

RESULTS

Based on 180 completed transfers, the clinical pregnancy rate (CPR) per embryo transferred in the donor egg cycles was 41.7%. EB3 results from women with a 'High' grading showed a superior CPR (54.0%) compared with 'Low' (22.2% CPR) or 'Borderline' (37.4%) cases (P = 0.024). Similarly, following 379 autologous oocyte transfers, the CPR was 36.1% overall, with major variations between the 'High' (43.8%), 'Low' (17.5%) and 'Borderline' (34.8%) groups (P = 0.0008). Implantation rates showed similar significant trends in the 'High' versus 'Low' groups of 40.4% versus 16% (P = 0.048) in donor oocyte transfers, and 30.8% versus 16.1% (P = 0.025) in autologous oocyte transfers.

CONCLUSIONS

The distribution patterns and percentage expression of EB3 assessed by a flow cytometry grading system shows a significant relationship to implantation rate and CPR success in ART cycles and may thus represent a useful additional tool for the assessment of uterine receptivity.