Expression of the slit‐diaphragm protein, nephrin, in experimental diabetic nephropathy: differing effects of anti‐proteinuric therapies

Background. Mutations in the gene coding for the podocyte slit‐pore membrane protein, nephrin, are responsible for the Finnish‐type congenital nephrotic syndrome. The present study sought to examine whether nephrin expression may also be altered in experimental diabetes, and how such changes related to the development of proteinuria. In addition, the study also sought to examine nephrin expression in animals treated with different anti‐proteinuric therapies. Methods. Nephrin gene expression and localization were examined in rats with streptozotocin‐induced diabetes at 6 months duration (proteinuric phase) and at 7 days (pre‐proteinuric phase). In addition, the effects of anti‐proteinuric drug therapies were also assessed in long‐term diabetic rats, treated with either the angiotensin‐converting enzyme inhibitor perindopril, or the blocker of advanced glycation end‐product formation, aminoguanidine. Nephrin expression was determined using quantitative real‐time PCR and in situ hybridization. Results. When compared with control animals, nephrin expression was reduced in the late proteinuric phase (45% reduction vs controls, P