Quick study: How gene activity in the placenta could affect the health of mothers and babies

THE QUESTION: A growing fetus depends on the placenta to perform the functions of several adult organs, including exchange of oxygen, nutrients, antibodies and waste products between itself and its mother. Problems with the placenta accompany several difficulties in pregnancy, including early labor and pre-eclampsia, a potentially deadly condition characterized by high blood pressure and the presence of protein in the urine.

Can differences in the active genes of the placenta be linked to abnormalities in maternal or fetal health, or even variations in later life?

THIS STUDY: Researchers surveyed the genes of the placentas of 19 women who gave successful full-term births at Lucile Packard Children's Hospital at Stanford. The team obtained 72 samples from different regions of the placentas. They used DNA microarrays—glass slides containing more than 40,000 DNA spots representing a range of human genes—to analyze the genes expressed throughout the placenta. They also compared placental genes to those in 35 normal human tissues.

THE RESULTS: The researchers identified genes expressed differently in the various parts of the placenta. They found a unique expression pattern for a group of genes that may be associated with pre-eclampsia. They also found sets of placental genes that differed according to the gender of the fetus, which raises the intriguing possibility of gender-specific functions of the placenta.

WHO MAY BE AFFECTED: Potentially, all fetuses and pregnant women. If gene-activity profiles could indicate that the mother or the fetus is heading for trouble, an obstetrician might be inclined to intervene.

WHY IT MATTERS: This early-stage work lays a foundation that is critical for future studies looking for differences between women who have problems during pregnancy and those who don't.

CAVEATS: This study only included samples from 19 women, all of whom had healthy pregnancies. More placentas from healthy pregnancies are needed to comprehensively cover the sources of normal placental gene differences. In addition, future studies by the group will address the genetic expression of problem pregnancies.

STANFORD CONNECTION: All four authors are from the School of Medicine: Ruchira Sood, PhD, research associate; professor of pathology James Zehnder, MD; obstetrics and gynecology professor Maurice Druzin, MD, and biochemistry professor Patrick Brown, MD, PhD.

FIND THIS STUDY: in the April 4 issue of the Proceedings of the National Academy of Sciences.