HMOX1 and diabetic kidney disease: Although the present study underscores the renoprotective effects of hemin therapy in diabetic nephropathy, and suggest that the suppression of extracellular matrix proteins like collagen-IV and fibronectin in hemin-treated ZDF are accompanied by increased expression of nephrin and improved renal function, these observations should be cautiously interpreted because this study does not provide unequivocal data that demonstrate the interaction among HO-1, collagen-IV, fibronectin and nephrin in the glomeruli.