Infusion of angiotensin-(1-7) reduces glomeruloscierosis through counteracting angiotensin II in experimental glomerulonephritis.

Recent identification of a counter-regulatory axis of the renin-angiotensin system, called angiotensin-conveiling enzyme 2-arigiotensin-(1-7) [ANG-(1-7)]-Mas receptor, may offer new targets for the treatment of renal fibrosis. We hypothesized that therapy with ANG-(1-7) would improve glomerulosclerosis through counteracting ANG II in experimental glomerulonephritis. Disease was induced in rats with the monoclonal anti-Thy-1 antibody, OX-7. Based on a three-dose pilot study, 576 μg·kg-1 day-1 ANG-(1-7) was continuously infused from day 1 using osmotic pumps. Measures of glomerulosclerosis include semiquantitative scoring of matrix proteins stained for periodic acid Schiff, collagen I, and fibronectin EDA+ (FN). ANG-(1-7) treatment reduced disease-induced increases in proteinuria by 75%, giomerular periodic acid Schiff staining by 48%, collagen I by 24%, and FN by 25%. The dramatic increases in transforming growth factor-β1, plasminogen activator inhibitor-1, FN, and collagen I mRNAs seen in disease control animals compared with normal rats were all significantly reduced by ANG-(1-7) administration (P < 0.05). These observations support our hypothesis that ANG-(1-7) has therapeutic potential for reversing glomerulosclerosis. Several results suggest ANG-(1-7) acts by counteracting ANG H effects: 1) renin expression in ANG-(1-7)-treated rats was dramatically increased as it is with ANG H blockade therapy; and 2) in vitro data indicate that ANG H-induced increases in mesangial cell proliferation and plasnilnogen activator inhibitor-1 overexpression are inhibited by ANG-( 1-7) via its binding to a specific receptor known as Mas. [ABSTRACT FROM AUTHOR]