RUDN researchers assessed the contribution of monocytes to the development of preeclampsia

RUDN University researchers have found a distinctive property of cells in the blood of patients with preeclampsia, a dangerous complication that occurs during pregnancy. The causes of this pathology are still unknown to scientists, but the results obtained may be evidence of one of the hypotheses of the origin of preeclampsia. Results are published in Scientific Reports.

In the second half of pregnancy, a pathological condition called preeclampsia may occur. At the same time, high blood pressure and proteinuria are observed. Such a dangerous complication can lead to long-term consequences for the mother and child, increases the risk of maternal and perinatal mortality. At the same time, scientists still do not know the causes of this pathology, nor the features of its course, nor the methods of its treatment. RUDN University researchers found a distinctive pattern in the composition of monocytes in patients with preeclampsia. Monocytes are innate immune cells that first circulate in the bloodstream and then settle in tissues and become macrophages. There are three types of monocytes – classical (CD14++), non-classical (CD16++) and mixed, or transitional, subpopulation.

“Preeclampsia remains the leading cause of maternal and fetal morbidity and mortality. On average, this complication occurs in 8% of pregnancies. Cells of monocyte-macrophage system play an important role in maintaining pregnancy because they maintain tolerance to a semi-allogeneic fetus. Monocytes are divided into two main subpopulations: classical and non-classical. It can be assumed that a change in the composition of monocytes can affect those organs where monocytes come from the bloodstream, in particular, the placenta. Our goal was to assess what happens to two subpopulations of monocytes in preeclampsia,” Polina Vishnyakova, PhD, Assistant at the Department of Histology, Cytology and Embryology, RUDN University.

Researchers at RUDN University studied the indicators in 33 patients. In 11 of them, the pregnancy proceeded without complications, the rest faced preeclampsia. Moreover, in 12 patients with preeclampsia, the pathology appeared early – before 34 weeks.

There was no difference in the absolute number of monocytes in normal pregnancy and pregnancy with complications. However, the proportion of classic monocytes was significantly lower in patients with late preeclampsia. RUDN scientists also conducted a transcriptomic analysis to see the genes the cells express and in what quantity. With its help, the researchers hypothesized that the cause of preeclampsia may be immunological stress, that is, a stress of the immune system. The hypothesis itself is not new, but the results obtained add arguments in its favor.

“Our results point to significant changes that occur with two opposite monocyte subpopulations in preeclampsia. Overall, our study reinforces the concept of immunological stress as a major factor that contributes to the development of preeclampsia. Moreover, it can be tracked by changes in the transcriptome profiles of monocytes,” Polina Vishnyakova, PhD, Assistant at the Department of Histology, Cytology and Embryology, RUDN University.