Comparative Pathomorphological Characteristics Of Placental Vessels From Pregnancies With High And Low Risk Of Preeclampsia

Relevance:  Preeclampsia is a common multisystem specific pregnancy disorder accompanied by remodeling of placental vessels.  Vascular structural changes are influenced by both systemic factors and local anomalies, such as umbilical cord pathology. The large variability and inconsistency of histomorphometric changes in placental vessels as markers of placental dysfunction emphasize the need for their further research using standardized methods of morphometric analysis.

The purpose of this work is to evaluate histomorphometric changes in the wall thickness and internal diameter of placental vessels during pregnancy with a different risk of preeclampsia based on screening in the first trimester and umbilical cord pathology. 

Materials and methods: A retrospective research included pregnant women grouped by preeclampsia risk (high and low) and additionally stratified by the presence of umbilical cord pathology. The placenta examination and the selection of fragments of placental tissue of the postpartum placenta were carried out in accordance with the consensus recommendations of the Amsterdam Placental Workshop Group. The sections were stained with hematoxylin and eosin and Masson trichrome. Morphometric measurements were performed using ImageJ software (version 1.52). The data were analyzed using the Mann-Whitney U-test with Bonferroni correction.
 
Results: Systemic and local factors had an impact on vascular remodeling, manifested in changes in wall thickness and diameter of macrovessels. In the low–risk group without umbilical cord pathology, the average vascular wall thickness was 14.4(11.6 - 17.8)µm, and the diameter of the vascular lumen was 124.9(98.4 – 142.6)µm. In placentas with a high risk of preeclampsia without umbilical cord pathology, a significant decrease in the wall thickness of placental vessels was observed to an average of 8.1(6.3 – 8.8)µm, accompanied by a significant expansion of the vascular lumen to 167.7(128.4 – 189.7)µm. The presence of umbilical cord pathology led to thickening of the wall of the proximal vessels 29.1(24.1-37.1)µm with a decrease in the lumen diameter to 93.7(82.7-105-5 )µm. The differences between the groups reached statistical significance (p<0.001).

Conclusion: This research highlights the combined effect of systemic factors (risk of preeclampsia) and local structural changes (umbilical cord pathology) on the remodeling of placental vessels. A decrease in the wall thickness of the placental vessels, accompanied by an increase in the internal diameter of the vessels, suggests significant structural changes that may be early diagnostic and prognostic markers of a newborn's predisposition to cardiovascular diseases.