Placental pathology, corticotropin-releasing hormone, timing of parturition, and fetal growth in the pregnancy outcomes and community health study

Perfluorooctanoic acid induces transcriptomic alterations in second trimester human cytotrophoblasts

Poly- and perfluroroalkylated substances (PFAS) are a major class of surfactants used in industry applications and consumer products. Despite efforts to reduce the usage of PFAS due to their environmental persistence, compounds such as perfluorooctanoic acid (PFOA) are widely detected in human blood and tissue. Although growing evidence supports that prenatal exposures to PFOA and other PFAS are linked to adverse pregnancy outcomes, the target organs and pathways remain unclear. Recent investigations in mouse and human cell lines suggest that PFAS may impact the placenta and impair trophoblast function. In this study, we investigated the effects of PFOA on cytotoxicity and the transcriptome in cultured second trimester human cytotrophoblasts (CTBs). We show that PFOA significantly reduces viability and induces cell death at 24 h, in a concentration-dependent manner. At subcytotoxic concentrations, PFOA impacted expression of hundreds of genes, including several molecules (CRH, IFIT1, and TNFSF10) linked with lipid metabolism and innate immune response pathways. Furthermore, in silico analyses suggested that regulatory factors such as peroxisome proliferator-activated receptor-mediated pathways may be especially important in response to PFOA. In summary, this study provides evidence that PFOA alters primary human CTB viability and gene pathways that could contribute to placental dysfunction and disease.

Extracellular vesicles from maternal uterine cells exposed to risk factors cause fetal inflammatory response

Background

Fetal cell-derived exosomes (extracellular vesicles, 40–160 nm) are communication channels that can signal parturition by inducing inflammatory changes in maternal decidua and myometrium. Little is known about maternal cell-derived exosomes and their functional roles on the fetal side. This study isolated and characterized exosomes from decidual and myometrial cells grown under normal and inflammatory/oxidative stress conditions and determined their impact on fetal membrane cells.

Methods

Decidual and myometrial cells were grown under standard culture conditions (control) or exposed for 48 h to cigarette smoke extract or tumor necrosis factor-α, as proxies for oxidative stress and inflammation, respectively. Exosomes were isolated from media (differential ultra-centrifugation followed by size exclusion chromatography), quantified (nano particle tracking analysis), and characterized in terms of their size and morphology (cryo-electron microscopy), markers (dot blot), and cargo contents (proteomics followed by bioinformatics analysis). Maternal exosomes (10⁹/mL) were used to treat amnion epithelial cells and chorion trophoblast cells for 24 h. The exosome uptake by fetal cells (confocal microscopy) and the cytokine response (enzyme-linked immunosorbent assays for IL-6, IL-10, and TNF-α) was determined.

Results

Exosomes from both decidual and myometrial cells were round and expressed tetraspanins and endosomal sorting complexes required for transport (ESCRT) protein markers. The size and quantity was not different between control and treated cell exosomes. Proteomic analysis identified several common proteins in exosomes, as well as unique proteins based on cell type and treatment. Compared to control exosomes, pro-inflammatory cytokine release was higher in both amnion epithelial cell and chorion trophoblast cell media when the cells had been exposed to exosomes from decidual or myometrial cells treated with either cigarette smoke extract or tumor necrosis factor-α. In chorion trophoblast cells, anti-inflammatory IL-10 was increased by exosomes from both decidual and myometrial cells.

Conclusion

Various pathophysiological conditions cause maternal exosomes to carry inflammatory mediators that can result in cell type dependent fetal inflammatory response.

Associations Between Placental Corticotropin-Releasing Hormone, Maternal Cortisol, and Birth Outcomes, Based on Placental Histopathology

Preterm birth remains the leading cause of neonatal morbidity and mortality, with complex biochemical pathways requiring continued understanding and assessment. The objective of this study is to assess the associations between maternal cortisol and placental corticotropin-releasing hormone (placental CRH) concentrations with birth outcomes when stratified by placental histopathology. We conducted an analysis of 112 singleton pregnancies who received betamethasone between 23 and 34 weeks' gestation. Maternal blood and saliva were collected prior to betamethasone administration and samples assayed for plasma cortisol (pCort), salivary cortisol (sCort), and placental CRH levels. Placental findings were characterized as inflammatory, maternal vascular underperfusion (MVU), or no pathology, and compared for the outcomes of placental CRH, pCort, and sCort levels, gestational age at birth (GAB), and birthweight percentiles (BWP). Thirty-six subjects were characterized as inflammatory, 38 as MVU, and 38 without placental abnormalities. Histopathology groups differed significantly on placental CRH levels, GAB, and BWP. Post hoc tests suggested that the MVU group had higher placental CRH than the inflammatory or no pathology groups, and despite delivering earlier than the other two groups, the inflammatory group had infants with significantly higher BWP. No differences existed between groups in terms of mean plasma or sCort levels. Higher placental CRH and pCort levels were associated with earlier GAB in the overall sample, but when split by group, these associations remained significant only among the MVU group. Higher placental CRH was also associated with lower BWP in the overall sample but did not remain significant when split by group. Higher sCort was associated with lower BWP only in the MVU group. There is differentiation of placental CRH, cortisol, and birth outcomes when evaluated by placental histopathology. This highlights the importance of evaluating birth outcomes within the context of placental histopathology.