Diabetogenic transferrin damages podocytes in early human diabetic nephropathy

The exact mechanisms by which growth hormone (GH) damages the kidney induci ng diabetic nephropathy has not yet been elucidated. Recently, it has been shown that transferrin has the same diabetogenic effects of GH, being its m ediator. Transferrin was studied using immunohistochemistry and immunoelect ron microscopy in cases of early diabetic nephropathy, and in controls. Tra nsferrin was only found in diabetic cases in podocytes and Bowman's capsule cells, but also in the tubular cells of both diabetic and non-diabetic con trols. Immune-electron microscopy for the presence of transferrin showed po sitive signals in the cytoplasm of diabetic podocytes, but not in pedicels. This selective deposition was associated with signs of organelle and cytos keleton damage. On the basis of previous evidence and present glomerular fi ndings, these results suggest an indirect diabetogenic effect on the kidney by GH mediated through transferrin.