bims-reprim 2022-02-13 papers

Issue of 2022–02–13
eight papers selected by
Iva Filipovic, Karolinska Institutet

J Reprod Immunol. 2022 Jan 29. pii: S0165-0378(22)00017-1. [Epub ahead of print]150 103489

Eutopic endometrial immune profile of infertility-patients with and without endometriosis.

Nadine Freitag, Dunja M Baston-Buest, Jan-Steffen Kruessel, Udo R Markert, Tanja N Fehm, Alexandra P Bielfeld.

There is growing evidence that changes in the eutopic endometrial immune profile are a cause of endometriosis-associated infertility. Women affected by endometriosis experience a 2-fold increased risk of infertility compared to healthy controls. In our study we aimed to map out endometrial expressions of uterine natural killer cells, plasma cells, macrophages and the chemokine CXC-motif ligand 1 (CXCL1) as well as its main receptors CXC-motif receptor 2 (CXCR2) and Syndecan-1 in infertility-patients with endometriosis. 36 infertility patients were included of which 19 suffered from endometriosis and 17 served as a control cohort. All patients underwent endometrial scratching in the secretory phase and immunohistochemical staining which was evaluated by three independent observers. In endometriosis-patients, a higher concentration of macrophages coincided with an elevated number of uterine natural killer cells or plasma cells. Patients with endometriosis also showed a higher endothelial expression of VEGF-A. Furthermore, absence of stromal expression of SDC-1 was associated with an elevated level of uNK in general. Therefore, our study links endometriosis to an altered immune cell population in the eutopic endometrium, which might be a new approach to diagnosing endometriosis in infertility patients.

Keywords: Endometriosis; Endometrium; Human; Immune cells; Infertility

DOI: https://doi.org/10.1016/j.jri.2022.103489

Trends Immunol. 2022 Feb 04. pii: S1471-4906(22)00007-2. [Epub ahead of print]

Maternal inflammation and its ramifications on fetal neurodevelopment.

Ho-Keun Kwon, Gloria B Choi, Jun R Huh.

Exposure to heightened inflammation in pregnancy caused by infections or other inflammatory insults has been associated with the onset of neurodevelopmental and psychiatric disorders in children. Rodent models have provided unique insights into how this maternal immune activation (MIA) disrupts brain development. Here, we discuss the key immune factors involved, highlight recent advances in determining the molecular and cellular pathways of MIA, and review how the maternal immune system affects fetal development. We also examine the roles of microbiomes in shaping maternal immune function and the development of autism-like phenotypes. A comprehensive understanding of the gut bacteria-immune-neuro interaction in MIA is essential for developing diagnostic and therapeutic measures for high-risk pregnant women and identifying targets for treating inflammation-induced neurodevelopmental disorders.

DOI: https://doi.org/10.1016/j.it.2022.01.007

Fertil Steril. 2022 Feb 03. pii: S0015-0282(21)02225-1. [Epub ahead of print]

Endometrial cytokines in patients with and without endometriosis evaluated for infertility.

Hilde Jørgensen, Peter Fedorcsak, Keith Isaacson, Erin Tevonian, Amy Xiao, Michael Beste, Erik Qvigstad, Douglas Lauffenburger, Linda Griffith.

OBJECTIVE: To evaluate whether endometrial molecular profiles distinguish subsets of patients according to clinical characteristics, and to infer dysregulated immune networks, by measuring cytokines, chemokines, and growth factors in endometrial biopsy specimens from a cohort of infertile women with a high incidence of endometriosis.
DESIGN: Prospective cohort study.
SETTING: Department of Gynecology at a university hospital.
PATIENT(S): Patients undergoing laparoscopy for infertility assessment (n = 103).
INTERVENTION(S): Endometrial biopsies were performed during surgery. Fertility outcome and clinical parameters were registered preoperatively and after 6 months.
MAIN OUTCOME MEASURE(S): The concentrations of 48 factors in endometrial biopsy specimens were analyzed with respect to clinical status in univariate and multivariate frameworks.
RESULT(S): The concentrations of 44 factors from endometrial tissues of 74 patients were suitable for analysis. Although the tissue concentrations of interleukin (IL)15, IL-7, and interferon γ-induced protein (IP)-10 were individually lower in patients with endometriosis than in those without endometriosis, the differences were not significant after multiple comparison. However, multivariate modeling incorporating covariation showed separation between subsets of endometriotic and nonendometriotic patients, based predominantly on IP-10, monocyte chemoattractant protein-1, IL-16, and IL-18; this result was independent of cycle and fertility status. Analysis restricted to endometrial tissues from the secretory phase separated endometriotic and nonendometriotic patients by a combination of IL-15, IP-10, monocyte chemoattractant protein-1, IL-16, and IL-18. This combination suggests a uterine natural killer cell defect. We found no significant correlations between endometrial cytokines and fertility outcome.
CONCLUSION(S): A molecular signature in endometrial tissue was able to distinguish endometriotic from nonendometriotic patients, implicating uterine natural killer cells in endometriosis.

Keywords: Cytokine; endometrial biopsy; endometriosis; infertility

DOI: https://doi.org/10.1016/j.fertnstert.2021.11.024

Hum Reprod Open. 2022 ;2022(1): hoab043

The role of endometrial B cells in normal endometrium and benign female reproductive pathologies: a systematic review.

Mengni Shen, Elizabeth O'Donnell, Gabriela Leon, Ana Kisovar, Pedro Melo, Krina Zondervan, Ingrid Granne, Jennifer Southcombe.

STUDY QUESTION: What are the similarities and differences in endometrial B cells in the normal human endometrium and benign reproductive pathologies?
SUMMARY ANSWER: Endometrial B cells typically constitute <5% of total endometrial CD45+ lymphocytes, and no more than 2% of total cells in the normal endometrium, and while their relative abundance and phenotypes vary in benign gynaecological conditions, current evidence is inconsistent.
WHAT IS KNOWN ALREADY: B cells are vitally important in the mucosal immune environment and have been extensively characterized in secondary lymphoid organs and tertiary lymphoid structures (TLSs), with the associated microenvironment germinal centre. However, in the endometrium, B cells are largely overlooked, despite the crucial link between autoimmunity and reproductive pathologies and the fact that B cells are present in normal endometrium and benign female reproductive pathologies, scattered or in the form of lymphoid aggregates (LAs). A comprehensive summary of current data investigating B cells will facilitate our understanding of endometrial B cells in the endometrial mucosal immune environment.
STUDY DESIGN SIZE DURATION: This systematic review retrieved relevant studies from four databases (MEDLINE, EMBASE, Web of Science Core Collection and CINAHL) from database inception until November 2021.
PARTICIPANTS/MATERIALS SETTING METHODS: The search strategy combined the use of subject headings and relevant text words related to 'endometrium', 'B cells' and B-cell derivatives, such as 'antibody' and 'immunoglobulin'. Non-benign diseases were excluded using cancer-related free-text terms, and searches were limited to the English language and human subjects. Only peer-reviewed research papers were included. Each paper was graded as 'Good', 'Fair' or 'Poor' quality based on the NEWCASTLE-OTTAWA quality assessment scale. Only 'Good' quality papers were included.
MAIN RESULTS AND THE ROLE OF CHANCE: Twenty-seven studies met the selection criteria and were included in this review: 10 cross-sectional studies investigated B cells in the normal endometrium; and 17 case-control studies compared the characteristics of endometrial B cells in control and benign female reproductive pathologies including endometritis, endometriosis, infertility, abnormal uterine bleeding, endometrial polyps and uterine fibroids. In all studies, B cells were present in the endometrium, scattered or in the form of LAs. CD20+ B cells were more abundant in patients with endometritis, but the data were inconsistent as to whether B-cell numbers were increased in endometriosis and patients with reproductive pathologies.
LIMITATIONS REASONS FOR CAUTION: Although only 'good' quality papers were included in this systematic review, there were variations in patients' age, diagnostic criteria for different diseases and sample collection time among included studies. Additionally, a large number of the included studies only used immunohistochemistry as the identification method for endometrial B cells, which may fail to provide an accurate representation of the numbers of endometrial B cells.
WIDER IMPLICATIONS OF THE FINDINGS: Histological studies found that endometrial B cells are either scattered or surrounded by T cells in LAs: the latter structure seems to be under hormonal control throughout the menstrual cycle and resembles TLSs that have been observed in other tissues. Further characterization of endometrial B cells and LAs could offer insights to endometrial B-cell function, particularly in the context of autoimmune-associated pathologies, such as endometriosis. Additionally, clinicians should be aware of the limited value of diagnosing plasma cell infiltration using only CD138.
STUDY FUNDING/COMPETING INTERESTS: This study was funded by Finox Biotech. The authors have no conflicts of interest to declare.
PROSPERO REGISTRATION NUMBER: This systematic review was registered in PROSPERO in January 2020 (PROSPERO ID: CRD42020152915).

Keywords: B cells; endometriosis; endometrium; female infertility; immunology; infertility; recurrent miscarriage

DOI: https://doi.org/10.1093/hropen/hoab043

Hum Reprod. 2022 Feb 11. pii: deac019. [Epub ahead of print]

Uterine fluid microRNAs are dysregulated in women with recurrent implantation failure.

Carolina von Grothusen, Caroline Frisendahl, Vijayachitra Modhukur, Parameswaran Grace Lalitkumar, Maire Peters, Omid R Faridani, Andres Salumets, Nageswara Rao Boggavarapu, Kristina Gemzell-Danielsson.

STUDY QUESTION: Is the composition of microRNAs (miRNAs) in uterine fluid (UF) of women with recurrent implantation failure (RIF) different from that of healthy fertile women?
SUMMARY ANSWER: The composition of miRNAs in UF of women with RIF is different from that of healthy fertile women and the dysregulated miRNAs are associated with impaired endometrial receptivity and embryo implantation.
WHAT IS KNOWN ALREADY: It has previously been demonstrated that the miRNAs secreted from endometrial cells into the UF contribute to the achievement of endometrial receptivity. Endometrial miRNAs are dysregulated in women with RIF.
STUDY DESIGN, SIZE, DURATION: In this descriptive laboratory case-control study, miRNA abundancy was compared between UF collected during implantation phase from healthy fertile women (n = 17) and women with RIF (n = 34), which was defined as three failed IVF cycles with high-quality embryos.
PARTICIPANTS/MATERIALS, SETTING, METHODS: Recruitment of study subjects and sampling of UF were performed at two university clinics in Stockholm, Sweden and Tartu, Estonia. The study participants monitored their menstrual cycles using an LH test kit. The UF samples were collected on Day LH + 7-9 by flushing with saline. Samples were processed for small RNA sequencing and mapped for miRNAs. The differential abundance of miRNAs in UF was compared between the two groups using differential expression analysis (DESeq2). Further downstream analyses, including miRNA target gene prediction (miRTarBase), Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis (g:Profiler) and external validation using relevant published data, were performed on the dysregulated miRNAs. Two miRNAs were technically validated with quantitative real-time PCR (RT-PCR).
MAIN RESULTS AND THE ROLE OF CHANCE: After processing of the sequencing data, there were 15 samples in the healthy fertile group and 33 samples in the RIF group. We found 61 differentially abundant UF miRNAs (34 upregulated and 27 downregulated) in RIF compared to healthy women with a false discovery rate of <0.05 and a fold change (FC) of ≤-2 or ≥2. When analyzed with published literature, we found that several of the differentially abundant miRNAs are expressed in endometrial epithelial cells and have been reported in endometrial extracellular vesicles and in association with endometrial receptivity and RIF. Their predicted target genes were further expressed both in the trophectodermal cells of blastocyst-stage embryos and endometrial mid-secretory epithelial cells, as assessed by publicly available single-cell transcriptome-sequencing studies. Pathway analysis further revealed that 25 pathways, having key roles in endometrial receptivity and implantation, were significantly enriched. Hsa-miR-486-5p (FC -20.32; P-value = 0.004) and hsa-miR-92b-3p (FC -9.72; P-value = 0.004) were successfully technically validated with RT-PCR.
LARGE SCALE DATA: The data are available in Gene Expression Omnibus (GEO) at https://www.ncbi.nlm.nih.gov/geo/ with GEO accession number: GSE173289.
LIMITATIONS, REASONS FOR CAUTION: This is a descriptive study with a limited number of study participants. Moreover, the identified differentially abundant miRNAs should be validated in a larger study cohort, and the predicted miRNA target genes and enriched pathways in RIF need to be confirmed and further explored in vitro.
WIDER IMPLICATIONS OF THE FINDINGS: RIF is a major challenge in the current IVF setting with no diagnostic markers nor effective treatment options at hand. For the first time, total miRNAs have been extensively mapped in receptive phase UF of both healthy women with proven fertility and women diagnosed with RIF. Our observations shed further light on the molecular mechanisms behind RIF, with possible implications in future biomarker and clinical treatment studies.
STUDY FUNDING/COMPETING INTEREST(S): This work was financially supported by the Swedish Research Council (2017-00932), a joint grant from Region Stockholm and Karolinska Institutet (ALF Medicine 2020, FoUI-954072), Estonian Research Council (PRG1076), Horizon 2020 innovation (ERIN, EU952516) and European Commission and Enterprise Estonia (EU48695). The authors have no competing interests to declare for the current study.

Keywords: embryo-endometrial crosstalk; endometrial receptivity; in vitro fertilization; infertility; microRNAs; recurrent implantation failure; uterine fluid

DOI: https://doi.org/10.1093/humrep/deac019

Hum Reprod. 2022 Feb 11. pii: deac022. [Epub ahead of print]

Use of 'omics for endometrial timing: the cycle moves on.

John D Aplin, Adam Stevens.

For some years, the prospect of precise and personalized timing of the endometrial cycle for optimal embryo replacement has been held out as a potential solution to low implantation rates. It is envisaged that a receptive state can be defined and reached at a predictable time, and embryo replacement performed in synchrony. In the last century, morphological changes characteristic of the mid secretory phase were defined in precisely timed cycles in women of proven fertility, but when deviations from this standardized schedule occur, their significance for implantation has remained uncertain. 'Omics technologies have been widely advocated for staging the endometrial cycle and defining a set of biochemical requirements for implantation, but after two decades of research, improvements to pregnancy rates have not followed, and there is a striking lack of agreement regarding the molecular characterization of the receptive state. Some of the rationale underlying these problems is now emerging with the application of higher-level computational and biological methodology. Here, we consider the challenges of defining an endometrial phenotype that can support implantation and continuing pregnancy. Receptivity may be an emergent trait depending on contributions from multiple proteins that have low pathway connectivity. We recommend that authors choose language which rigorously avoids the implication that protocols for molecular staging of the mid secretory phase inherently identify a state of receptivity to the implanting blastocyst.

Keywords: ART; ERA; embryo implantation; embryo transfer; endometrium; genomics; proteomics; receptivity; transcriptomics; window

DOI: https://doi.org/10.1093/humrep/deac022

Nat Rev Endocrinol. 2022 Feb 08.

Uterine bleeding: how understanding endometrial physiology underpins menstrual health.

Varsha Jain, Rohan R Chodankar, Jacqueline A Maybin, Hilary O D Critchley.

Menstruation is a physiological process that is typically uncomplicated. However, up to one third of women globally will be affected by abnormal uterine bleeding (AUB) at some point in their reproductive years. Menstruation (that is, endometrial shedding) is a fine balance between proliferation, decidualization, inflammation, hypoxia, apoptosis, haemostasis, vasoconstriction and, finally, repair and regeneration. An imbalance in any one of these processes can lead to the abnormal endometrial phenotype of AUB. Poor menstrual health has a negative impact on a person's physical, mental, social, emotional and financial well-being. On a global scale, iron deficiency and iron deficiency anaemia are closely linked with AUB, and are often under-reported and under-recognized. The International Federation of Gynecology and Obstetrics have produced standardized terminology and a classification system for the causes of AUB. This standardization will facilitate future research endeavours, diagnosis and clinical management. In a field where no new medications have been developed for over 20 years, emerging technologies are paving the way for a deeper understanding of the biology of the endometrium in health and disease, as well as opening up novel diagnostic and management avenues.

DOI: https://doi.org/10.1038/s41574-021-00629-4

Reprod Fertil. 2021 Jan;2(1): 47-57

Pelvic pain correlates with peritoneal macrophage abundance not endometriosis.

Douglas A Gibson, Frances Collins, Bianca De Leo, Andrew W Horne, Philippa T K Saunders.

Endometriosis is a chronic neuroinflammatory pain condition affecting ~180 million women worldwide. Surgical removal or hormonal suppression of endometriosis lesions only relieves pain symptoms in some women and symptomatic relapse following treatment is common. Identifying factors that contribute to pain is key to developing new therapies. We collected peritoneal fluid samples and clinical data from a cohort of women receiving diagnostic laparoscopy for suspected endometriosis (n = 52). Peritoneal fluid immune cells were analysed by flow cytometry and data compared with pain scores determined using the pain domain of the Endometriosis Health Profile Questionnaire (EHP-30) in order to investigate the association between peritoneal immune cells and pain symptoms. Pain scores were not different between women with or without endometriosis, nor did they differ according to disease stage; consistent with a poor association between disease presentation and pain symptoms. However, linear regression and correlation analysis demonstrated that peritoneal macrophage abundance correlated with the severity of pelvic pain. CD14high peritoneal macrophages negatively correlated with pain scores whereas CD14low peritoneal macrophages were positively correlated, independent of diagnostic outcome at laparoscopy. Stratification by pain subtype, rather than endometriosis diagnosis, resulted in the most robust correlation between pain and macrophage adundance. Pain score strongly correlated with CD14high (P = 0.007) and CD14low (P = 0.008) macrophages in patients with non-menstrual pain and also in patients who reported dysmennorhea (CD14high P = 0.021, CD14low P = 0.019) or dysparunia (CD14high P = 0.027, CD14low P = 0.031). These results provide new insight into the association between peritoneal macrophages and pelvic pain which may aid the identification of future therapeutic targets.
Lay summary: Endometriosis is a common condition where cells similar to those that line the womb are found elsewhere in the body. It is associated with inflammation and pain in the pelvis and affects ~180 million women worldwide. Current treatments are not effective for all patients and we, therefore, need to understand what causes pain in order to develop new treatments. We investigated the types of immune cells present within the pelvis of women undergoing investigation for suspected endometriosis. Disease diagnosis and stage (I-IV) was recorded along with pain score determined by questionnaire. We characterised the immune cells present and compared them to disease stage and pain score. We found that pelvic pain was linked to the abundance of immune cells but, surprisingly, not to disease stage. These findings suggest that immune cells are closely associated with pain severity in endometriosis and may be good targets for future endometriosis treatments.

Keywords: endometriosis; macrophage; pain; peritoneal

DOI: https://doi.org/10.1530/RAF-20-0072