Angiotensin II Local Hyperreactivity in the Progression of IgA Nephropathy

Abstract Immunologic and hemodynamic factors are likely to work in synergism in the progression of immunoglobulin A nephropathy (IgAN) toward sclerosis. The local activation of the renin-angiotensin system may be one of the most relevant mechanisms. We investigated the hemodynamic effects of the acute administration of angiotensin-converting enzyme inhibitor (ACEI) (captopril 50 mg). The glomerular filtration rate (GFR) and the effective renal plasma flow (ERPF) were measured by 51 Cr-EDTA and 125 I hippurate clearances. The correspondent filtration fractions (FFs) in basal conditions and after administration of ACEI were calculated, then the changes in FF (ΔFF and %ΔFF) were determined. We studied 27 IgAN patients. Eighteen patients had normal renal function (GFR, 112 ± 19 mL/min/1.73 m 2 ) and nine had moderate renal impairment (GFR, 54 ± 13 mL/min/1.73 m 2 ). Sixteen patients had proteinuria≥ 0.5 g/d. In addition, 12 glomerulonephritis control cases and eight healthy subjects were investigated. After the administration of ACEI in healthy subjects we observed slight modifications in the GFR, a significant increase in the ERPF ( P P P P P P P P P P P P