Comparison of Angiogenic Factors in the Placentas of Parturient Women with COVID-19

Since the beginning of the pandemic, few studies have explored the histopathological and molecular characteristics of placentas from SARS-CoV-2-positive pregnant women. This study aimed to investigate changes in the expression of angiogenic growth factors in the placentas of SARS-CoV-2-infected pregnant women (COVID-19 group) and compare them with placentas from non-infected women (control group). Placentas collected at birth from 20 healthy women (control group) and 20 women who tested positive for COVID-19 were prepared for histopathological analysis. Immunohistochemical staining was performed on placental tissues using antibodies against Angiotensin-Converting Enzyme 2 (ACE2), Vascular Endothelial Growth Factor (VEGF), Vascular Endothelial Growth Factor Receptor 1 (VEGFR-1), and Platelet-Derived Growth Factor (PDGF). Initially, the presence of SARS-CoV-2 in placental tissue was evaluated through ACE2 immunohistochemical staining. ACE2 expression was weak in the placental syncytiotrophoblast cells of non-infected women, whereas it was markedly increased in the syncytiotrophoblasts of placentas from women infected with COVID-19. VEGF expression was strong in the endothelial and stromal cells of villi in the control group, but significantly reduced in the villi of infected placentas. VEGFR-1 was strongly expressed in the endothelial membranes of villi in the control group, but expression was notably weaker in infected placentas. PDGF expression was strong in the syncytiotrophoblast and stromal cells of the control group but was significantly weaker in COVID-19-positive placentas. VEGF, VEGFR-1, and PDGF were strongly expressed in the placental villi of the control group, and their marked reduction in COVID-19-positive placentas suggests that SARS-CoV-2 infection may adversely affect the development and differentiation of the placental villous tree. © The Author(s), under exclusive licence to the Faculty of Medicine, Comenius University in Bratislava 2025.