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Objectives: Antiphospholipid syndrome (APS) is an autoimmune disease driven by antiphospholipid antibodies (aPL). Currently, APS diagnosis requires a combination of clinical manifestations (thrombosis and/or obstetric morbidity) and the persistent presence of at least one criteria aPL: anti-cardiolipin antibodies (aCL), anti-β2-glycoprotein I antibodies (aβ2GPI) or lupus anticoagulant (LA). Patients with suggestive obstetric symptoms but lacking criteria aPL face diagnostic challenges. Non-criteria aPL screening may enhance discrimination. This study proposes a classification incorporating both criteria and non-criteria antibodies to improve obstetric APS diagnosis., Methods: Blood samples from non-pregnant women ( n  = 68) with a history of vascular, obstetric, or vascular and obstetric manifestations were analysed. Among them, 30 had previous diagnosis of APS. Healthy women with proven gestational success were included as controls ( n  = 16). Criteria and non-criteria (anti-phosphatidylglycerol, anti-phosphatidylethanolamine, anti-phosphatidylinositol, anti-phosphatidylserine and anti-phosphatidic acid) IgG aPL were evaluated by ELISA and coagulation tests. Based on the resulting aPL profile, patients were reclassified. Responsiveness to treatment was obtained from medical records., Results: Criteria aPL levels marginally differentiated women previously managed as obstetric APS from unexplained/other causes of obstetric morbidity. Including non-criteria aPL improved separation. The proposed classification identified an obstetric APS group that exhibits non-criteria aPL and aβ2GPI titres below the cut-off but higher than healthy women (7.88 vs. 2.47 SGU, P  = 0.006). Compared to cases of other causes of obstetric morbidity, these patients retrospectively responded better to aspirin and/or heparin treatment (71.43% vs. 11.11%, P  = 0.035)., Conclusions: Assessing non-criteria antibodies may identify isolated obstetric APS cases benefiting from established therapies., Competing Interests: The authors declare no conflict of interest., (© 2024 The Author(s). Clinical & Translational Immunology published by John Wiley & Sons Australia, Ltd on behalf of Australian and New Zealand Society for Immunology, Inc.)

Introduction: The transplacental passage of cells between a mother and her fetus, known as microchimerism, is a less studied process during pregnancy. The frequency of maternal microchimeric cells in fetal tissues in physiological pregnancies and mechanisms responsible for transplacental cell trafficking are poorly understood. This study aimed to evaluate the placental trafficking of maternal peripheral blood mononuclear cells (PBMC) using human ex vivo placenta perfusion., Methods: Ten placentas and maternal PBMC were obtained after healthy pregnancies. Flow cytometry was used to characterize PBMC subtypes. They showed a higher percentage of CD3 + T cells compared to CD56 + NK cells. The isolated PBMC were stained with a fluorescent dye and perfused through the maternal circuit of the placenta in an ex vivo perfusion system. Subsequent immunofluorescence staining for CD3 + T cells and CD56 + NK cells was performed on placental tissue sections, and the number of detectable PBMC in different tissue areas was counted using fluorescence microscopy., Results: The applied method allowed discrimination of perfused autologous maternal cells from cells resident in the placenta before perfusion. Further, it allows additional immunohistochemical labelling and distinction of immune cell subsets. Perfused PBMC were detected in all analyzed placentas, mostly in contact to the syncytiotrophoblast. CD3 + T cells were identified more frequently than CD56 + NK cells and some CD3 + T cells were found inside fetoplacental tissues and vasculature. The results indicate that also other PBMCs than T or NK cells adhere to or enter villous tissue, but they have not been specified in this analysis., Discussion: Previous studies have detected maternal cells in the fetal circulation which we could mimick in our ex vivo placenta perfusion experiments with fluorescence labelled autologous maternal PBMC. The applied experimental settings did not allow comparison of transmigration abilities of PBMC subsets, but slight modifications of the model will permit further studies of cell transfer processes and microchimerism in pregnancy., Competing Interests: Declaration of competing interest Herewith, I declare that no conflict of interest exists with any of the authors., (Copyright © 2023 The Authors. Published by Elsevier Ltd.. All rights reserved.)

Research Question: Do microRNAs (miRNAs) play a role in regulating endoplasmic reticulum stress (ERS) and unfolded protein response (UPR) in decidualized cells and endometrium associated with reproductive failures?, Design: Endometrial stromal cell line St-T1b was decidualized in vitro with 8-Br-cAMP over 5 days, or treated with the ERS inducer thapsigargin. Expression of ERS sensors, UPR markers and potential miRNA regulators was analysed by quantitative PCR. Endometrial biopsies from patients with recurrent pregnancy loss (RPL) and recurrent implantation failure (RIF) were investigated for the location of miRNA expression., Results: Decidualization of St-T1b cells resulted in increased expression of ERS sensors including ATF6α, PERK and IRE1α, and the UPR marker, CHOP. TXNIP, which serves as a link between the ERS pathway and inflammation, as well as inflammasome NLRP3 and interleukin 1β expression increased in decidualized cells. An in-silico analysis identified miR-17-5p, miR-21-5p and miR-193b-3p as miRNAs potentially involved in regulation of the ERS/UPR pathways and inflammation associated with embryo implantation. Their expression decreased significantly (P ≤ 0.0391) in non-decidualized cells in the presence of thapsigargin. Finally, expression of the selected miRNAs was localized by in-situ hybridization in stromal and glandular epithelial cells in endometrial samples from patients with RPL and RIF. Expression in stroma cells from patients with RPL was lower in comparison with stroma cells from patients with RIF., Conclusions: Decidualization in St-T1b cells is accompanied by ERS/UPR processes, associated with an inflammatory response that is potentially influenced by miR-17-5p, miR-21-5p and miR-193b-3p. These miRNAs are expressed differentially in stromal cells from patients with RPL and RIF, indicating an alteration in regulation of the ERS/UPR pathways., (Copyright © 2023 The Author(s). Published by Elsevier Ltd.. All rights reserved.)

Background: Serotonin (5-HT) is a biogenic monoamine with diverse functions in multiple human organs and tissues. During pregnancy, tightly regulated levels of 5-HT in the fetoplacental unit are critical for proper placental functions, fetal development, and programming. Despite being a non-neuronal organ, the placenta expresses a suite of homeostatic proteins, membrane transporters and metabolizing enzymes, to regulate monoamine levels. We hypothesized that placental 5-HT clearance is important for maintaining 5-HT levels in the fetoplacental unit. We therefore investigated placental 5-HT uptake from the umbilical circulation at physiological and supraphysiological levels as well as placental metabolism of 5-HT to 5-hydroxyindoleacetic acid (5-HIAA) and 5-HIAA efflux from trophoblast cells., Methods: We employed a systematic approach using advanced organ-, tissue-, and cellular-level models of the human placenta to investigate the transport and metabolism of 5-HT in the fetoplacental unit. Human placentas from uncomplicated term pregnancies were used for perfusion studies, culturing explants, and isolating primary trophoblast cells., Results: Using the dually perfused placenta, we observed a high and concentration-dependent placental extraction of 5-HT from the fetal circulation. Subsequently, within the placenta, 5-HT was metabolized to 5-hydroxyindoleacetic acid (5-HIAA), which was then unidirectionally excreted to the maternal circulation. In the explant cultures and primary trophoblast cells, we show concentration- and inhibitor-dependent 5-HT uptake and metabolism and subsequent 5-HIAA release into the media. Droplet digital PCR revealed that the dominant gene in all models was MAO-A, supporting the crucial role of 5-HT metabolism in placental 5-HT clearance., Conclusions: Taken together, we present transcriptional and functional evidence that the human placenta has an efficient 5-HT clearance system involving (1) removal of 5-HT from the fetal circulation by OCT3, (2) metabolism to 5-HIAA by MAO-A, and (3) selective 5-HIAA excretion to the maternal circulation via the MRP2 transporter. This synchronized mechanism is critical for regulating 5-HT in the fetoplacental unit; however, it can be compromised by external insults such as antidepressant drugs., (© 2023. BioMed Central Ltd., part of Springer Nature.)

Molecular communication between a pathogen and its host is crucial for a successful interplay. Extracellular vesicles (EVs) act as mediators for the delivery of molecular signals among pathogens or between pathogens and the host. Toxoplasma gondii (T. gondii), an intracellular parasite with a worldwide presence, produces EVs itself, or induces the secretion of EVs from infected host cells potentially having capacities to modulate the host immune response. T. gondii infection is particularly important during pregnancy. Depending on the gestational age at the time of infection, the parasite can be transmitted through the placenta to the fetus, causing clinical complications such as jaundice, hepatosplenomegaly, chorioretinitis, cranioencephalic abnormalities, or even death. T. gondii infection is related to a pro-inflammatory immune response in both mother and fetus, which may enhance parasite transmission, but the implication of EV signaling in this process remains unclear. In this review, we summarize the current knowledge on EV release from T. gondii and its human host cells in regard to the immunological consequences and the passage through the placenta., Competing Interests: Declaration of Competing Interest The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2023 The Authors. Published by Elsevier B.V. All rights reserved.)

Placenta accreta spectrum (PAS) is one of the major causes of maternal morbidity and mortality worldwide with increasing incidence. PAS refers to a group of pathological conditions ranging from the abnormal attachment of the placenta to the uterus wall to its perforation and, in extreme cases, invasion into surrounding organs. Among them, placenta accreta is characterized by a direct adhesion of the villi to the myometrium without invasion and remains the most common diagnosis of PAS. Here, we identify the potential regulatory miRNA and target networks contributing to placenta accreta development. Using small RNA-Seq followed by RT-PCR confirmation, altered miRNA expression, including that of members of placenta-specific miRNA clusters (e.g., C19MC and C14MC), was identified in placenta accreta samples compared to normal placental tissues. In situ hybridization (ISH) revealed expression of altered miRNAs mostly in trophoblast but also in endothelial cells and this profile was similar among all evaluated degrees of PAS. Kyoto encyclopedia of genes and genomes (KEGG) analyses showed enriched pathways dysregulated in PAS associated with cell cycle regulation, inflammation, and invasion. mRNAs of genes associated with cell cycle and inflammation were downregulated in PAS. At the protein level, NF-κB was upregulated while PTEN was downregulated in placenta accreta tissue. The identified miRNAs and their targets are associated with signaling pathways relevant to controlling trophoblast function. Therefore, this study provides miRNA:mRNA associations that could be useful for understanding PAS onset and progression., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2023 Murrieta-Coxca, Barth, Fuentes-Zacarias, Gutiérrez-Samudio, Groten, Gellhaus, Köninger, Marz, Markert and Morales-Prieto.)