Effect of cyclosporin A on renal function in patients with glomerulonephritis

Background and objective: Cyclosporin A (CsA) plays a confounding part in t he treatment of nephrotic syndrome. Renal hemodynamics and glomerular perms electivity were investigated in patients with glomerulonephritis to analyse the antiproteinuric action of CsA and to differentiate between nephrotoxic and immunosuppressive effects. Methods: We studied 19 patients with nephrotic syndrome after 6 months of t reatment with CsA (membranous glomerulonephritis-MGN, n=10; focal segmental sclerosing glomerulonephritis-FSGN, n=5; minimal changes glomerulonephriti s MCGN, n=4). Patients were studied three times within 3 weeks with (A) and without (B) CsA treatment (A-B-A'). Blood pressure, creatinine. proteinuri a, C-In, C-PAH, C-Dex were measured (analysis according to the model of Dee n et al., Am J Physiol. 1985; 249:374). Results: GFR (C-In) increased significantly after withdrawal of CsA from 54 +/-7.3 to 64 +/-8.5ml/min (p<0.01). Proteinuria increased after withdrawal of cyclosporin (B) between 21% (MGN) and 45% (FSGN). After withdrawal of C sA (B) there was no change of FCdex in patients with MGN and FSGN. Withdraw al of CsA in patients with MCGN induced a significant decrease in glomerula r selectivity in the high molecular range. Conclusion: These data demonstrate that CsA is able to induce even in the s hort term a significant increase in glomerular Permselectivity in MCGN. The acute effects on GFR predominantly determined the acute antiproteinuric ef fects in patients with MGN and FSGN.