Increased expression of selectins in kidneys of patients with diabetic nephropathy

In diabetic nephropathy leukocytes, mainly composed of monocytes/macrophages, which accumulate in the glomeruli and the interstitium, play an important part in the progression of glomerulosclerosis. The infiltration of leukocytes into inflammatory tissues or atherosclerotic lesions is mediated by adhesion molecules, which are expressed on the vascular endothelial cells, although little is known about the mechanism of leukocyte infiltration into diabetic renal tissues. P- and E-selectin are leukocyte adhesion molecules, which are expressed on the vascular endothelial cells and promote the adhesion of leukocytes to the endothelium. We investigated the expression of P- and E-selectin in the kidney tissue of patients with diabetic nephropathy and compared it with that of patients with other glomerular diseases (minimal change nephrotic syndrome, membranous nephropathy, IgA nephropathy, mesangioproliferative glomerulonephritis, and lupus nephritis). Expression of P- and E-selectin were both significantly increased in the glomeruli and the interstitium of patients with diabetic nephropathy as compared with those with other glomerular diseases. P- and E-selectin were both expressed along the glomerular capillaries and the peritubular capillaries in the interstitium. Neither P- nor E-selectin were correlated with the number of infiltrated leukocytes in the glomeruli, however, interestingly the E-selectin expression on peritubular capillaries was correlated with the number of infiltrated CD14 positive cells in the interstitium. These results suggest that E-selectin may play a key role in leukocyte infiltration into the renal interstitium in patients with diabetic nephropathy.