Total Renin in Preeclamptic Placenta

Abstract

Objective: Total renin, i.e., prorenin and active renin, synthesized in the uteroplacental unit plays an important role in maintaining the low-resistance state in the fetoplacental vasculature during normal pregnancy. In preeclampsia, characterized by generalized vasoconstriction, local dysfunction of the renin-angiotensin system may be involved. Because the source of total renin during pregnancy is mainly the fetoplacental unit and the ovaries, the aim of this study was to examine if there are differences in the placental concentration of total renin in normal and preeclamptic pregnancy.

Methods: Total renin concentrations in the homogenates of 10 normal and 12 preeclamptic human placentas were measured with a time-resolved immu-nofluorometric assay.

Results: The mean total renin concentration was 22.6 ng (range 10.2-58.3) per milligram of protein of normal placental tissue and 24.8 ng (range 12.8-52.8) per milligram of protein in preeclamptic placentas.

Conclusions: Although the renin-angiotensin system participates in the regulation of blood flow and pressure during pregnancy, we could not show any differences in total renin concentrations between preeclamptic and normal placentas.

Key Words:

• Placenta
• Preeclampsia
• Total renin