Placenta accreta spectrum ultrasound stage and fetal growth

Visualization of placental villi: Three-dimensional ultrasound imaging shows coral-like placental villous trees

We introduce a new microflow imaging technique, which can show the blood perfusion and morphological structure of placental villi.

Placenta accreta spectrum disorder at single-cell resolution: a loss of boundary limits in the decidua and endothelium

BACKGROUND

Placenta accreta spectrum disorders are associated with severe maternal morbidity and mortality. Placenta accreta spectrum disorders involve excessive adherence of the placenta preventing separation at birth. Traditionally, this condition has been attributed to excessive trophoblast invasion; however, an alternative view is a fundamental defect in decidual biology.

OBJECTIVE

This study aimed to gain insights into the understanding of placenta accreta spectrum disorder by using single-cell and spatially resolved transcriptomics to characterize cellular heterogeneity at the maternal-fetal interface in placenta accreta spectrum disorders.

STUDY DESIGN

To assess cellular heterogeneity and the function of cell types, single-cell RNA sequencing and spatially resolved transcriptomics were used. A total of 12 placentas were included, 6 placentas with placenta accreta spectrum disorder and 6 controls. For each placenta with placenta accreta spectrum disorder, multiple biopsies were taken at the following sites: placenta accreta spectrum adherent and nonadherent sites in the same placenta. Of note, 2 platforms were used to generate libraries: the 10× Chromium and NanoString GeoMX Digital Spatial Profiler for single-cell and spatially resolved transcriptomes, respectively. Differential gene expression analysis was performed using a suite of bioinformatic tools (Seurat and GeoMxTools R packages). Correction for multiple testing was performed using Clipper. In situ hybridization was performed with RNAscope, and immunohistochemistry was used to assess protein expression.

RESULTS

In creating a placenta accreta cell atlas, there were dramatic difference in the transcriptional profile by site of biopsy between placenta accreta spectrum and controls. Most of the differences were noted at the site of adherence; however, differences existed within the placenta between the adherent and nonadherent site of the same placenta in placenta accreta. Among all cell types, the endothelial-stromal populations exhibited the greatest difference in gene expression, driven by changes in collagen genes, namely collagen type III alpha 1 chain (COL3A1), growth factors, epidermal growth factor-like protein 6 (EGFL6), and hepatocyte growth factor (HGF), and angiogenesis-related genes, namely delta-like noncanonical Notch ligand 1 (DLK1) and platelet endothelial cell adhesion molecule-1 (PECAM1). Intraplacental tropism (adherent versus non-adherent sites in the same placenta) was driven by differences in endothelial-stromal cells with notable differences in bone morphogenic protein 5 (BMP5) and osteopontin (SPP1) in the adherent vs nonadherent site of placenta accreta spectrum.

CONCLUSION

Placenta accreta spectrum disorders were characterized at single-cell resolution to gain insight into the pathophysiology of the disease. An atlas of the placenta at single cell resolution in accreta allows for understanding in the biology of the intimate maternal and fetal interaction. The contributions of stromal and endothelial cells were demonstrated through alterations in the extracellular matrix, growth factors, and angiogenesis. Transcriptional and protein changes in the stroma of placenta accreta spectrum shift the etiologic explanation away from "invasive trophoblast" to "loss of boundary limits" in the decidua. Gene targets identified in this study may be used to refine diagnostic assays in early pregnancy, track disease progression over time, and inform therapeutic discoveries.

Placenta Previa et Percreta: A Potentially Life-Threatening Condition

Placenta percreta occurs in about 5% of placenta accreta spectrum (PAS) and causes high maternal and fetal peripartum morbidity/mortality. A 34-year-old multiparous 4G2P (1xcesarean section (CS)) was admitted to hospital at the 34th week of gestation. Transvaginal ultrasound revealed a placenta previa totalis et percreta with a small tissue layer towards the bladder. Ultrasound was crucial for further planning. An interdisciplinary setting was established based on this life-threatening diagnosis. Due to the onset of labor one day later, a CS was performed. Intraoperatively, the suspicion was confirmed of a placenta previa et percreta with CS scar infiltration. Due to the life-threatening bleeding risk, simultaneous subtotal hysterectomy was needed. The diagnosis was confirmed histologically. The higher the number of previous CS, the higher the PASrate. Placenta percreta is the most severe form of this, characterized by placental invasion through the entirety of the myometrium and possibly into extrauterine tissues. This case demonstrates the great importance of prenatal diagnosis with the realization of dimensions of this very rare finding, especially with an increasing CS rate and other associated complications. Due to the close interdisciplinary cooperation of the prenatal diagnosticians, obstetricians, and anesthesiologists with optimal care in a specialized center, the otherwise high morbidity/mortality can be minimized.