[Physiopathology of diabetic nephropathy: what we learn from transplantation]

The contribution of clinical transplantation to the understanding of the pathophysiology of diabetic nephropathy is reviewed. Isolated kidney transplantation into diabetic recipients provides the opportunity to observe early lesions of recurrence, consisting in mesangium expansion and glomerular basement membrane thickening; in these patients, tight glycaemic control can significantly slow down the progression of recurrence. Simultaneous kidney-pancreas transplantation effectively prevents recurrence. Isolated pancreas transplantation in the presence of established diabetic nephropathy can prevent its progression and seems even able to induce its regression in the long-term provided transplantation takes place at an early stage of diabetic nephropathy. In summary, clinical transplantation confirms that the quality of glycaemic control is the main determinant of both the development and progression of diabetic nephropathy. It remains a unique opportunity to study its reversibility.