Six proteins implicated in early-onset preeclampsia

Preeclampsia's key symptom is high maternal blood pressure, and serious cases can lead to maternal organ failure, low infant birth weight, or maternal or fetal death. Preeclampsia before 34 weeks of pregnancy has a higher risk of severe outcomes, especially for the fetus. But it's difficult for health care providers to detect this condition before harmful symptoms appear, because little is known about what causes it. So, Jing Li and colleagues set out to characterize proteins in placenta tissue that may offer clues about the cause of early-onset preeclampsia and serve as targets for early detection or treatment.

The researchers collected placenta tissue from 30 pregnant people, half with early-onset preeclampsia and half with healthy pregnancies. Li and colleagues used mass spectrometry to screen molecular fragments in each sample, followed by a software program to match the fragments to their associated proteins. This process pinpointed 59 proteins that were present in different amounts (either higher or lower) for preeclamptic placenta tissue samples versus healthy placenta tissue samples. The researchers chose 16 of these proteins to target with a different, more sensitive mass spectrometry method, which more precisely measured the amounts of each protein. Of these 16 proteins, six were present in statistically different amounts across tissue sample groups:

• Preeclamptic placenta tissue had higher levels of monocarboxylate transporter 4, ERO1-like protein alpha and pappalysin-2. These proteins are involved in synthesizing proteins and regulating growth hormones.
• Preeclamptic placenta tissue had lower levels of desmin, caldesmon and keratine 18. These proteins play key roles in cardiovascular complications, like an enlarged heart; blood flow in placental muscle cells; estrogen signaling and cell health in the uterus lining.

Altogether, the results suggest that cardiovascular complications or the estrogen cycle could be linked to the development of early-onset preeclampsia. The team says that more research is needed, but identifying these six proteins serves as a promising first step toward improved detection and treatment of this life-threatening condition.

The authors acknowledge funding from the Natural Science Foundation of Shandong Province.