Excessive turnover of cells in the placenta may trigger an unnatural increase in blood pressure that puts mother and baby at risk, researchers say.
It's called preeclampsia, a condition that can develop after the 20th week of pregnancy, prompting an unhealthy increase in the mother's blood pressure that can result in premature delivery. Georgia Health Sciences University researchers want to know if dead placental cells in some cases produce an exaggerated immune response that constricts blood vessels and raises blood pressure.
"During pregnancy, there is a natural turnover of trophoblasts - the main cell type in the placenta," said Dr. Stella Goulopoulou, a postdoctoral fellow in the Medical College of Georgia Department of Physiology at GHSU. "In pregnancies with preeclampsia, we see exaggerated rates of cell death compared to normal pregnancies."
When those cells die, they can release their mitochondria, or powerhouse, which then binds to a key receptor, Toll-like receptor 9, and causes an inflammatory response. Previous research has linked mitochondria released by damaged or dead cells to inflammatory responses associated with sepsis and heart failure.
"Blood vessels, like other tissues, have receptors that respond to mitochondrial DNA and other components of the mitochondria," Goulopoulou said. "DNA from the mitochondria can specifically activate Toll-like receptor 9, which is present in blood vessels. In our experiments, we found that activating Toll-like receptor 9 causes the blood vessels to constrict more than normal."
Goulopoulou has received a $25,000 Vision Grant from the Preeclampsia Foundation to study whether that is behind the generalized global inflammation and if that ultimately impairs the growing baby's supply of nutrients and oxygen. Vision Grants provide initial funding for novel lines of research to encourage young investigators to study causes and treatments of preeclampsia.
"The placenta is a dynamic tissue," she said. "We think it is the source of the mitochondria implicated in preeclampsia because it is the only tissue that undergoes such cell turnover during pregnancy. It also goes away, in most cases, when the placenta and baby are delivered."