Effects of erythropoietin-gene electrotransfer in rats with adenine-induced renal failure

Background. We previously demonstrated that erythropoietin (Epo) expression increases in five-sixths nephrectomized rats, after muscle-targeted gene transfer by in vivo electroporation, using plasmid DNA expressing rat Epo (pCAGGS-Epo). Here, we apply this method to a rat model with severe anemia associated with chronic renal failure; these rats have hematocrit levels in the 30-35% range, similar to those in humans with end-stage renal disease. Methods: Wistar rats were treated to produce adenine-induced uremia. The uremic rats were then treated with muscle-targeted gene transfer using pCAGGS-Epo. Some uremic rats died from chronic renal failure; one of these was dissected, and the kidneys were histologically examined. For the remaining rats, we measured body weight and blood pressure, and obtained blood samples regularly. Results: The uremic rats showed severe anemia, with hematocrit levels at 32.6 +/- 3.3%. Epo-gene transfer increased Epo expression and serum Epo levels, and also increased the hematocrit levels to 64.5 +/- 4.8%. The dose of pCAGGS-Epo used in this study did not induce severe hypertension. Conclusions: Continuous Epo-gene expression improves the anemia associated with chronic renal failure, and without severe side effects. Our results support the potential use of gene electrotransfer for human gene therapy applications. Copyright (C) 2003 S. Karger AG, Basel.