Elevation of (Pro)Renin and (Pro)Renin Receptor in Preeclampsia

Abstract

Objective: Preeclampsia (preE), a syndrome of hypertension, proteinuria, and edema, has many elusive triggers. The renin-angiotensin system has been implicated in preE pathogenesis. In this study, we test the hypothesis that (pro)renin levels are increased in preE patients and that levels of (pro)renin and (pro)renin receptor ((P)RR) are elevated in a rat model of preE.

Methods: We recruited 30 preE and 43 normal pregnant consenting patients. We used normally pregnant rats (NP, n = 10) and pregnant rats receiving weekly injections of desoxycorticosterone acetate and whose drinking water was replaced with 0.9% saline (preE, n = 10). Plasma and placental levels of (pro)renin were assayed by ELISA. Placental and kidney (P)RR was measured both by immunoblotting and immunohistochemistry.

Results: The mean plasma (pro)renin of 27.1±5.2 in preE patients differs from that in patients without preE: 14.8±5.2 ng Ang I/ml/hour (P < 0.0001). In rats, both plasma (NP: 22.7±4.3 and preE: 49.2±10.0 ng Ang I/ml/hour) and placental (NP: 152±24 and preE: 302±39 ng/g tissue) levels of (pro)renin were higher (P < 0.001) in preE compared to NP rats. (P)RR expression was greater (P < 0.05) in placental tissue of preE rats, while kidney (P)RR expression was similar.

Conclusion: Elevated levels of circulating (pro)renin have been observed in preE patients and in a rat model of preE. We also found the increased expression of placental (P)RR in preE rats.

Keywords: (pro)renin; (pro)renin receptor; blood pressure; hypertension; placenta; preeclampsia; renin–angiotensin system..