Vascular endothelial growth factor expression in myometrial resistance arteries in women with preeclampsia

Abstract

It has recently been demonstrated that induced endothelial damage upregulates VEGF expression in medial smooth muscle cells of the arterial wall. The purpose of this study is to determine whether there is difference in VEGF expression in placentae and myometrial resistance arteries from patients with preeclampsia and those from controls to clarify the source of increased systemic level of VEGF in preeclampsia. : Placentae were collected immediately after cesarean section and a small piece of full-thickness uterine myometrium was excised from the upper margin of cesarean section incision sites from normal pregnant women (n = 10) and preeclampsia patients (n = 7). For VEGF immunohistochemistry (IHC), sections were incubated with a polyclonal goat anti-human VEGF, and the remaining procedure was performed using the ABC kit. VEGF mRNA in situ hybridization (ISH) was performed with paraffin-embedded tissue blocks using VEGF probe. For detection, the sections were covered with streptavidin-AP and incubated for 20 minutes and washed in TBS for 5 minutes and then covered with BCIP/NBT and incubated in the dark for 60 minutes and washed in water for 5 minutes. In placental tissue, VEGF was identified primarily in syncytiotrophoblasts in IHC and mRNA ISH, and there were no differences in staining between placentae from preeclampsia and those from control group. We also identified VEGF staining in smooth muscle cell in myometrium and perivascular smooth muscle in myometrial resistance arteries. However, there were no differences in VEGF staining between preeclampsia and control groups. This study suggests placenta and perivascular smooth muscle are not the origin of the increased circulating VEGF in preeclampsia. To understand the role of VEGF in preeclampsia clearly, further studies are required to find out the sites of increased VEGF synthesis and changes in VEGF metabolism in preeclampsia.