Protein Linked to Pregnancy Complication
Elevated levels of HtrA1 may warn of pending preeclampsia
THURSDAY, Feb. 2, 2006 (HealthDay News) -- Elevated levels of a protein found in placental tissues may be a warning sign of preeclampsia, a dangerous pregnancy complication in which a woman's blood pressure dramatically rises, researchers report.
Dr. Brian Brost and his colleagues at the Mayo Clinic were to present their findings Wednesday at the Society for Maternal-Fetal Medicine annual meeting in Miami.
"We're the first to find this association between the protein, HtrA1 and preeclampsia," said Brost, an associate professor of obstetrics and gynecology at the Mayo Clinic.
He emphasized that the findings are preliminary, and that preeclampsia has remained a baffling complication of pregnancy. "People have been searching for years for what causes preeclampsia," he said.
The condition affects up to 8 percent of pregnancies worldwide, according to Brost, and can lead to premature delivery and the need for a Caesarean section. In worst cases, it can cause disability or death to the mother and fetus.
While the new findings are preliminary, they could lead to a blood test that might predict the condition, the researchers said. Currently, there is no such test.
In the study, Brost and his team looked at third-trimester placental tissues from nine women with normal blood pressure, nine with severe preeclampsia, and three with mild preeclampsia. Those with preeclampsia had higher levels of the protein, and that is associated with greater placental distress, Brost said.
"The protein was more likely to be found in the women with preeclampsia," he said, adding that the pathologist who examined the tissues did not know if he was examining specimens from women with or without the condition.
It was already known that HtrA1 is involved in programmed cell death, cell change and "invasiveness," or the cells' ability to invade and colonize new areas of the body. The process can be healthy, as it is when it establishes the growth of the placenta in the uterus during the first trimester of pregnancy. Or it can be unhealthy, as researchers who have studied the role of the protein in cancer have learned.
Brost's team discovered that the higher levels of HtrA1 found in the placental tissues of women with severe preeclampsia might hamper correct functioning during the second stage of growth of key placental cells called cytotrophoblasts. These cells work to migrate to the uterus to establish the placenta.
Another expert, Dr. Ananth Karumanchi, an assistant professor of medicine and obstetrics and gynecology at Harvard University, said the study is "interesting" but preliminary.
So far, he said, "all they have shown is that the protein is present in placental tissue. But they have not yet shown that it leads to increased levels in the blood."
Such a scenario is quite possible, Karumanchi said, but needs to be proven. Brost agreed, saying that is one of the next areas of research.
Until a predictive test is reality, women can heed warning signs of preeclampsia, said Karumanchi, who is also an attending physician at Beth Israel Deaconess Medical Center in Boston.
"If they have new headaches, new swelling around the eyes or the legs, they should contact their doctor," he said.
If preeclampsia is diagnosed early, a doctor may prescribe medications to lower blood pressure and buy time. If the condition is diagnosed late in pregnancy, the doctor might decide to deliver the baby early, he said.
To learn more about preeclampsia, visit the U.S. National Library of Medicine.