Abstract 550: Plasma Angiotensin-(1-12) Level Is Elevated And Correlates With Proteinuria In Patients With Chronic Kidney Diseases

Abstract

Angiotensin-(1-12) [Ang-(1-12)], C-terminally extended form of Ang I, is an alternative precursor of Ang II. Although angiotensinogen, a precursor of both Ang I and Ang-(1-12), is reportedly one of markers of kidney disease, little is known about role of Ang-(1-12) in pathological status especially in human. To address this issue, we measured plasma and urinary Ang-(1-12) by enzyme immunoassay in 4 healthy volunteers and 15 patients with biopsy-proven chronic kidney diseases (CKD). CKD group included minor glomerular abnormality (n=3), IgA nephropathy (n=8), minimal change nephritic syndrome (n=4). Ang-(1-12) level was 55-fold higher in urine than in plasma (Figure; 4.12±1.55 vs 0.075±0.006 ng/mL, P<0.05). Neither plasma Ang-(1-12) nor urinary Ang-(1-12) was correlated with blood pressure. Plasma Ang-(1-12) was positively correlated with urinary protein and tended to be negatively correlated with estimated glomerular filtration ratio (eGFR; Figure). Plasma Ang-(1-12) was higher in the CKD group than in the control (Figure; 0.083±0.006 vs 0.045±0.005 ng/mL, P<0.01). On the other hand, urinary Ang-(1-12) was correlated with neither urinary protein nor eGFR. Urinary Ang-(1-12) tended to be higher in the CKD group than in control (4.94±1.9 vs 1.05±0.6 ng/mL, respectively). The present study showed for the first time that plasma Ang-(1-12) level is elevated in patients with CKD and suggests that increased plasma Ang-(1-12) plays a nephropathic role.