Modern Tech Teases out Important Role of the Placenta

The placenta, sometimes called afterbirth, is described as an organ that develops in the uterus during pregnancy. It acts as something of an interface between the mother’s womb and the unborn baby, connected via the umbilical cord. It provides oxygen and nutrients to the baby. The placenta attaches to the wall of the uterus.

Although research has been conducted on placentas for decades, three important studies were recently published related to the science of the placenta.

One of the studies, conducted by researchers at the Wellcome Trust Sanger Institute in the UK, The Cavendish Laboratory at the University of Cambridge, and the European Bioinformatics Institute, also in Cambridge, UK, was published in the journal Nature. The researchers described the transcriptomes of approximately 70,000 single cells from first-trimester placentas with matched maternal blood and decidual cells.

A second study, conducted by researchers at the University of Massachusetts Medical School, was published in the journal Nature Biotechnology. This research is related to the first in that it describes ways to silence gene expression of specific genes in the placenta that are linked to preterm preeclampsia. They identify short interfering RNAs (siRNAs) that can selectively silence the three sFLT1 mRNA isoforms that are responsible for placental overexpression of sFLT1, or soluble vascular endothelial growth factor receptor of placental origin.

The third research, by researchers with the University of Cambridge in the UK, was also published in Nature. They developed three-dimensional organoids, or mini-placentas, that mimic real placentas in the laboratory, and can be used as models too research the organ.

The New York Times also describes the Human Placenta Project at a Baltimore meeting, where researchers have developed techniques to study the placenta in real time. “That work,” The Times writes, “could help doctors diagnose dangerous complications in pregnancy—including pre-eclampsia (a form of high blood pressure), preterm birth and fetal growth restriction—early enough to intervene. It might also help to reveal why boys are much more vulnerable than girls to disorders of brain development, including schizophrenia, ADHD, autism, dyslexia and Tourette syndrome.”

Daniel R. Weinberg, director of the Lieber Institute for Brain Development in Baltimore, Md., told The Times, “The missing link between complications during pregnancy and development of the fetal brain has been hiding in plain sight for a long time. It’s the placenta.”

It’s not as if research hasn’t been conducted on the placenta. In the 1980s, C. Maureen Sander at Michigan State University ran the Placental Tissue Registry and conducted pathology research on human placentas. And chorionic villus sampling (CVS), a form of prenatal diagnosis that samples a tiny piece of the placenta, has been used to identify chromosome abnormalities like Down syndrome for decades.

But clearly, new molecular techniques have identified an even broader role at the genetic level of the placenta. They have also allowed for more study of the placenta while it is developing and performing its role in the mother, rather than post-delivery. “That’s too late,” George R. Saade, chief of obstetrics at the University of Texas Medical Branch, told The Times. “It’s like studying cardiac disease or any other medical condition just by doing an autopsy.”

In 2014, the National Institutes of Health (NIH) invested $80 million in placenta research in hopes of developing noninvasive methods for detecting placenta-based problems earlier. Many of the tests were only able to identify problems in the third trimester, which was too late for effective treatments.

Some researchers think magnetic resonance imaging (MRK) would be the most sensitive way of identifying placental problems. Research published in 2016 suggests that there is no link between MRI exposure during pregnancy and fetal or childhood outcomes. But many note that MRI isn’t used often in obstetricians’ offices, while ultrasounds machines are. And recent advances in ultrasound technology has improved the machine’s focus, including the ability to observe small blood vessels, and another called elastography that can examine the liver and measure the density of placental tissue.

Mostly pregnant women see their obstetricians almost weekly in the third trimester of pregnancy, but only intermittently during the first trimester. It’s possible, that as these types of screening and imaging tests become more useful, there will be more screening earlier in the pregnancy, where possible interventions can identify and prevent pregnancy complications.