β-Adrenoceptor Subtype Expression in Human Placenta and Umbilical Arteries in Normal and Preeclamptic Pregnancies

Abstract

Objectives. Preeclampsia is characterised by an abnormal vascular response to placentation and is associated with increased systemic vascular resistance and endothelial cell dysfunction. This study investigated the mRNA and protein expression of the β₂ and β₃-adrenoceptors (β-ARs) in placenta, and umbilical arteries, from preeclamptic and normotensive patients, to determine if the presence of preeclampsia altered the expression of either receptor. Methods. RT-PCR was used to identify β₂-AR and β₃-AR mRNA transcripts in the human placenta and in human umbilical arteries. Real-time RT-PCR was performed on total RNA from normal and preeclamptic placentae and umbilical arteries. Western blotting using antibodies for β₂-AR, β₃-AR, and β-actin was performed on total protein isolated from preeclamptic and normotensive placentae. Results. There was no significant difference in mRNA expression levels of β₂-AR and β₃-AR between normal and preeclamptic tissues (p > 0.05). No significant difference was observed in protein levels of β₂-AR and β₃-AR between placentae from normal and preeclamptic patients (p > 0.05). Conclusions. Aberrations in the β-adrenoceptor signalling systems, rather than in the regulation of expression of these receptors may occur in preeclampsia, as is the case in other hypertensive disorders.

Keywords:

• β-adrenoceptors
• Preeclampsia
• Placenta
• Umbilical artery