Characteristics of amniotic mesenchymal stromal cells derived from term and preterm labor

The maternal-fetal interface at single-cell resolution: uncovering the cellular anatomy of the placenta and decidua

The maternal-fetal interface represents a critical site of immunological interactions that can greatly influence pregnancy outcomes. The unique cellular composition and cell-cell interactions taking place within these tissues has spurred substantial research efforts focused on the maternal-fetal interface. With the recent advent of single-cell technologies, multiple investigators have applied such methods to gain an unprecedented level of insight into maternal-fetal communication. Here, we provide an overview of the dynamic cellular composition and cell-cell communications at the maternal-fetal interface as reported by single-cell investigations. By primarily focusing on data from pregnancies in the second and third trimesters, we aim to showcase how single-cell technologies have bolstered the foundational understanding of each cell's contribution to physiologic gestation. Indeed, single-cell technologies have enabled the examination of classical placental cells, such as the trophoblast, as well as uncovered new roles for structural cells now recognized as active participants in pregnancy and parturition, such as decidual and fetal stromal cells, which are reviewed herein. Furthermore, single-cell data investigating the ontogeny, function, differentiation, and interactions among immune cells present at the maternal-fetal interface, namely macrophages, T cells, dendritic cells, neutrophils, mast cells, innate lymphoid cells, natural killer cells, and B cells are discussed in this review. Moreover, a key output of single-cell investigations is the inference of cell-cell interactions, which has been leveraged to not only dissect the intercellular communications within specific tissues but also between compartments such as the decidua basalis and placental villi. Collectively, this review emphasizes the ways by which single-cell technologies have expanded the understanding of cell composition and cellular processes underlying pregnancy in mid-to-late gestation at the maternal-fetal interface, which can prompt their continued application to reveal new pathways and targets for the treatment of obstetrical disease.

Deciphering maternal-fetal cross-talk in the human placenta during parturition using single-cell RNA sequencing

Labor is a complex physiological process requiring a well-orchestrated dialogue between the mother and fetus. However, the cellular contributions and communications that facilitate maternal-fetal cross-talk in labor have not been fully elucidated. Here, single-cell RNA sequencing (scRNA-seq) was applied to decipher maternal-fetal signaling in the human placenta during term labor. First, a single-cell atlas of the human placenta was established, demonstrating that maternal and fetal cell types underwent changes in transcriptomic activity during labor. Cell types most affected by labor were fetal stromal and maternal decidual cells in the chorioamniotic membranes (CAMs) and maternal and fetal myeloid cells in the placenta. Cell-cell interaction analyses showed that CAM and placental cell types participated in labor-driven maternal and fetal signaling, including the collagen, C-X-C motif ligand (CXCL), tumor necrosis factor (TNF), galectin, and interleukin-6 (IL-6) pathways. Integration of scRNA-seq data with publicly available bulk transcriptomic data showed that placenta-derived scRNA-seq signatures could be monitored in the maternal circulation throughout gestation and in labor. Moreover, comparative analysis revealed that placenta-derived signatures in term labor were mirrored by those in spontaneous preterm labor and birth. Furthermore, we demonstrated that early in gestation, labor-specific, placenta-derived signatures could be detected in the circulation of women destined to undergo spontaneous preterm birth, with either intact or prelabor ruptured membranes. Collectively, our findings provide insight into the maternal-fetal cross-talk of human parturition and suggest that placenta-derived single-cell signatures can aid in the development of noninvasive biomarkers for the prediction of preterm birth.

Is Spontaneous Preterm Prelabor of Membrane Rupture Irreversible? A Review of Potentially Curative Approaches

There is still no curative treatment for the spontaneous preterm prelabor rupture of membranes (sPPROM), the main cause of premature birth. Here, we summarize the most recent methods and materials used for sealing membranes after sPPROM. A literature search was conducted between 2013 and 2023 on reported newborns after membranes were sealed or on animal or tissue culture models. Fourteen studies describing the outcomes after using an amniopatch, an immunologic sealant, or a mechanical cervical adapter were included. According to these studies, an increase in the volume of amniotic fluid and the lack of chorioamnionitis demonstrate a favorable neonatal outcome, with a lower incidence of respiratory distress syndrome and early neonatal sepsis, even if sealing is not complete and stable. In vivo and in vitro models demonstrated that amniotic stem cells, in combination with amniocytes, can spontaneously repair small defects; because of the heterogenicity of the data, it is too early to draw a thoughtful conclusion. Future therapies should focus on materials and methods for sealing fetal membranes that are biocompatible, absorbable, available, easy to apply, and easily adherent to the fetal membrane.