PP025. Measurement of the activity of the circulating and intrarenal renin–angiotensin system (iRAS) in pregnant and non-pregnant subjects

Abstract

To see if urinary angiotensinogen (uAGT)/creatinine and other urinary components of the RAS could be used to detect renal disease in pregnancy, as renal disease predisposes to preeclampsia. Plasma and urinary prorenin, ACE and AGT (iRAS) were measured by ELISA. Urinary active renin levels were measured enzymatically (9 males, 10 non pregnant, 61 Australian Indigenous pregnant women). No relationships between plasma RAS and iRAS were found. In non-pregnant females plasma AGT levels were inversely related to protein and albumin/creatinine (r=-0.72, P=0.019, n=10; r=-0.65, P=0.042, n=10). In pregnancy, plasma ACE levels were related to protein/creatinine (r=0.29, P=0.036, n=54). Urinary protein/creatinine was not related to iRAS activity (males and non-pregnant females) but in pregnancy was related to prorenin and active renin/creatinine (r=0.45, P=0.02, n=26 r=0.47, P<0.001, n=50). Urinary albumin/creatinine was related to uAGT and active renin/creatinine in pregnancy (r=0.39, P=0.005, n=51; r=0.37, P=0.008, n=51). uACE/creatinine and uAGT/creatinine were related (r=0.52, P<0.001, n=51). Excretion of components of the iRAS is independent of plasma levels. Not only is uAGT/creatinine related to albumin/creatinine but there are similar relationships with other iRAS components. Measurement of the iRAS in human pregnancy may detect early stage renal disease, endemic in Indigenous Australians.