Effects of erythropoietin and aminoguanidine on red blood cell deformability in diabetic azotemic and uremic patients

Impaired red blood cell-deformability (RBC-df) is noted in patients with diabetes and may play a role in the pathogenesis of microvasculopathy and nephropathy. We report the effects of erythropoietin (EPO) alone and combined with aminoguanidine (AG) for 1 year on RBC-df in predialysis patients (P-DPs) with renal insufficiency and in end-stage renal disease (ESRD) patients on maintenance hemodialysis (DPs). Nine P-DPs who received EPO 50 U/kg by subcutaneous injection 3 times per week are compared with 5 P-DPs treated without EPO (mean serum creatinine 4.1 +/- 0.1 versus 4.2 +/- 0.6 mg/dL, respectively). Twelve DPs (Kt/V = 1.5 +/- 0.1) were studied. Six DPs received AG 200 mg/every other day by mouth and EPO 50 U/kg by intravenous (IV) injection, and 6 DPs received EPO (50 U/kg) and placebo and served as control. RBC-df improved significantly in 9 P-DPs treated with EPO at 6 months (from 2.7 +/- 0.1 to 1.6 +/- 0.2, P = 0.005). This positive effect was sustained at 12 months (P = 0.005); there was no change in RBC-df in P-DPs receiving usual care without EPO. RSC-df improved significantly and progressively at 6 and 12 months in DPs treated with EPO and AG (from 2.2 +/- 0.2 to 1.8 +/- 0.2; P = 0.01; 1.2 +/- 0.1; P = 0.001, respectively); there was limited improvement in RBC-df in DPs treated with EPO and placebo. We conclude that EPO treatment significantly improved RBC-df in diabetic P-DPs, but EPO alone has no significant effect on RBC-df after 12 months in diabetic DPs. The combination of EPO and AG restores RBC-df to near-normal levels In diabetic DPs. We speculate that the effect of EPO on RBC-df seen in P-DPs and DPs is related to increased synthesis and influx of new and younger RBCs. AG may confer protection of RBCs in DPs by blocking advanced glycosylated end-product (AGE) formation. (C) 2001 by the National Kidney Foundation, Inc.