The Distributional Characteristics of M2 Macrophages in the Placental Chorionic Villi are Altered Among the Term Pregnant Women With Uncontrolled Type 2 Diabetes Mellitus

Disruption of the SP-A/SP-R210L (MYO18Aα) pathway prolongs gestation and reduces fetal survival during lipopolysaccharide-induced parturition in late gestation

Prolonged labor can lead to infection, fetal distress, asphyxia, and life-threatening harm to both the mother and the baby. Surfactant protein A (SP-A) was shown to contribute to the maintenance of pregnancy and timing of term labor. SP-A modulates the stoichiometric expression of the SP-R210L and SP-R210S isoforms of the SP-R210 receptor on alveolar macrophages (AMs). Lack of SP-R210L dysregulates macrophage inflammatory responses. We asked whether SP-A alters normal and inflammation-induced parturition through SP-R210 using SP-A- and SP-R210L-deficient mice. Labor and delivery of time-pregnant mice were monitored in real time using a time-lapse infrared camera. Intrauterine injection with either vehicle or Escherichia coli lipopolysaccharide (LPS) on embryonic (E) day 18.5 post coitus was used to assess the effect of gene disruption in chorioamnionitis-induced labor. We report that either lack of SP-A or disruption of SP-R210L delays parturition by 0.40 and 0.55 days compared with controls, respectively. LPS induced labor at 0.60, 1.01, 0.40, 1.00, and 1.31 days earlier than PBS controls in wild type (WT), SP-A-deficient, littermate controls, heterozygous, and homozygous SP-R210L-deficient mice, respectively. Lack of SP-A reduced litter size in PBS-treated mice, whereas the total number of pups delivered was similar in all LPS-treated mice. The number of live pups, however, was significantly reduced by 50%-70% in SP-A and SP-R210L-deficient mice compared with controls. Differences in gestational length were not associated with intrauterine growth restriction. The present findings support the novel concept that the SP-A/SP-R210 pathway modulates timely labor and delivery and supports fetal lung barrier integrity during fetal-to-neonatal transition in term pregnancy.NEW & NOTEWORTHY To our knowledge, this study is the first to report that SP-A prevents delay of labor and inflammation-induced stillbirth through the receptor SP-R210L.

The interplay of inflammation and placenta in maternal diabetes: insights into Hofbauer cell expression patterns

Introduction

Inflammation of the placenta is harmful to both the fetus and the mother. Inflammation is strongly associated with diabetes, a common complication of pregnancy. Hofbauer cells (HBCs), unique immune system cells of fetal origin in the placenta, play complex roles, including growth of placental villi and their branching, stromal remodelling, and angiogenesis.

Methods

Our study investigated the expression of IL-1β, IL-10, CYP2C8, CYP2C9, CYP2J2 and sEH in HBCs from patients with type 1 diabetes mellitus (T1DM) and gestational diabetes mellitus (GDM) compared to healthy controls using immunohistochemistry. We also assessed the structure of the villus stroma using Masson´s trichrome.

Results

In T1DM, HBCs showed inflammatory activation characterised by increased IL-1β and decreased CYP epoxygenase expression compared to normal placentas. Conversely, significant inflammation in HBCs appeared less likely in GDM, as levels of IL-1β and CYP epoxygenases remained stable compared to normal placentas. However, GDM showed a significant increase in sEH expression. Both types of diabetes showed delayed placental villous maturation and hypovascularisation, with GDM showing a more pronounced effect.

Conclusion

The expression profiles of IL-1β, CYP epoxygenases and sEH significantlly differ between controls and diabetic placentas and between T1DM and GDM. These facts suggest an association of the CYP epoxygenase-EETs-sEH axis with IL-1β expression as well as villous stromal hypovascularisation. Given the stable high expression of IL-10 in both controls and both types of diabetes, it appears that immune tolerance is maintained in HBCs.

Characterization of Hofbauer cell polarization and VEGF localization in human term placenta from active and inactive pregnant individuals

Physical activity (PA) during pregnancy is associated with parental and fetal health benefits; however, the mechanisms through which these benefits arise are yet to be fully understood. In healthy pregnancies Hofbauer cells (HBCs) comprise a heterogenous population containing CD206+ and CD206- phenotypes. In healthy pregnancies, CD206+ represent the majority, while dysregulations have been associated with pathological conditions. HBCs have also been identified as potential drivers of angiogenesis. As PA induces changes in macrophage polarization in non-pregnant populations, this novel study examined the relationship between PA and HBC polarization and to identify which HBC phenotypes express VEGF. Participants were classified as active or inactive, and immunofluorescence cell-labelling was used to quantify total HBCs, CD206+ HBCs, and the proportion of total HBCs expressing CD206. Immunofluorescent colocalization assessed which phenotypes expressed VEGF. Protein and mRNA expression of CD68 and CD206 were measured in term placenta tissue using Western blot and RT-qPCR, respectively. Both CD206+ and CD206- HBCs expressed VEGF. The proportion of CD206+ HBCs was elevated in active individuals; however, CD206 protein expression was observed to be lower in active participants. Combined with a lack of significant differences in CD206 mRNA levels, these findings suggest potential PA-mediated responses in HBC polarization and CD206 translational regulation.

Hyperglycemia disturbs trophoblast functions and subsequently leads to failure of uterine spiral artery remodeling

Uterine spiral artery remodeling is necessary for fetal growth and development as well as pregnancy outcomes. During remodeling, trophoblasts invade the arteries, replace the endothelium and disrupt the vascular smooth muscle, and are strictly regulated by the local microenvironment. Elevated glucose levels at the fetal-maternal interface are associated with disorganized placental villi and poor placental blood flow. Hyperglycemia disturbs trophoblast proliferation and invasion via inhibiting the epithelial-mesenchymal transition, altering the protein expression of related proteases (MMP9, MMP2, and uPA) and angiogenic factors (VEGF, PIGF). Besides, hyperglycemia influences the cellular crosstalk between immune cells, trophoblast, and vascular cells, leading to the failure of spiral artery remodeling. This review provides insight into molecular mechanisms and signaling pathways of hyperglycemia that influence trophoblast functions and uterine spiral artery remodeling.

Isolation of Decidual Macrophages and Hofbauer Cells from Term Placenta-Comparison of the Expression of CD163 and CD80

(1) Background: Placental immune cells are playing a very important role in a successful placentation and the prevention of pregnancy complications. Macrophages dominate in number and relevance in the maternal and the fetal part of the placenta. The evidence on the polarization state of fetal and maternal macrophages involved in both, healthy and pregnancy-associated diseases, is limited. There is no representative isolation method for the direct comparison of maternal and fetal macrophages so far. (2) Material and Methods: For the isolation of decidual macrophages and Hofbauer cells from term placenta, fresh tissue was mechanically dissected and digested with trypsin and collagenase A. Afterwards cell enrichment was increased by a Percoll gradient. CD68 is represented as pan-macrophage marker, the surface markers CD80 and CD163 were further investigated. (3) Results: The established method revealed a high cell yield and purity of the isolated macrophages and enabled the comparison between decidual macrophages and Hofbauer cells. No significant difference was observed in the percentage of single CD163⁺ cells in the distinct macrophage populations, by using FACS and immunofluorescence staining. A slight increase of CD80⁺ cells could be found in the decidual macrophages. Considering the percentage of CD80⁺CD163⁻ and CD80⁻CD163⁺ cells we could not find differences. Interestingly we found an increased number of double positive cells (CD80⁺CD163⁺) in the decidual macrophage population in comparison to Hofbauer cells. (4) Conclusion: In this study we demonstrate that our established isolation method enables the investigation of decidual macrophages and Hofbauer cells in the placenta. It represents a promising method for direct cell comparison, enzyme independently, and unaffected by magnetic beads, to understand the functional subsets of placental macrophages and to identify therapeutic targets of pregnancy associated diseases.