Aldosterone and Renin Concentration Abnormally Elevated in a Cohort of Normotensive Pregnant Women

Abstract During pregnancy the renin-angiotensin-aldosterone system (RAAS) undergo major changes to preserve normal blood pressure (BP), placenta blood flow and ensure a good pregnancy outcome. Abnormal aldosterone-renin metabolism is a risk factor for arterial hypertension and cardiovascular risk, but its association to pathological conditions in pregnancy remains unknown. Hence, clinical and subclinical novel biomarkers associated to these pathological conditions are encouraged to be identified. Aim: To study a cohort of normotensive pregnant women according to their serum aldosterone and plasma renin levels and assay their small extracellular vesicles (sEV) and a specific protein-cargo (LCN2, AT1R). Methods: A cohort of 54 normotensive pregnant women at term gestation. We determined the BP, serum aldosterone and plasma renin concentration. In a subgroup, we isolated their plasma sEVs and semi-quantify two EV-proteins (AT1R, LCN2). Results: We set a normal range of aldosterone and renin based in the interquartile range. We identified 5/54(9%) pregnant women with elevated aldosterone and low renin levels, and 5/54(9%) other pregnant women with low aldosterone and elevated renin levels. No differences were found in sEV-LCN2 nor sEV-AT1R. Conclusion: We found 18% normotensive pregnant women having either high aldosterone or high renin levels, suggesting a subclinical status similar to a primary aldosteronism or a hyperreninemia. Both would evolve to pathological conditions in presence a second challenge affecting the maternal vascular physiology or the BP. sEVs and its specific cargo are encouraged to be further studied in order to clarify its role as potential biomarkers of RAAS alterations in pregnant women.