Kyoji Hirata

Increased Expression of Intercellular Adhesion Molecule-1 (ICAM-1) in Diabetic Rat Glomeruli: Glomerular Hyperfiltration Is a Potential Mechanism of ICAM-1 Upregulation

Mononuclear cells, including monocytes/macrophages and T-cells, are considered to be involved in the progression of diabetic nephropathy, although the mechanism of their recruitment into diabetic glomeruli is unclear. The intercellular adhesion molecule-1 (ICAM-1) promotes the infiltration of leukocytes into atherosclerotic lesions as well as inflammatory tissues. In the present study, we investigated the expression of ICAM-1 in the glomeruli of streptozotocin-induced diabetic rats. The expression of ICAM-1 was increased significantly during the early stage of diabetes. The number of mononuclear cells, primarily monocytes/macrophages and lymphocytes, was significantly increased in diabetic glomeruli. Mononuclear cell infiltration into diabetic glomeruli was prevented by anti-ICAM-1 monoclonal antibody. Insulin treatment decreased ICAM-1 expression and mononuclear cell infiltration. The ICAM-1 expression on cultured human umbilical vein endothelial cells was not induced under high glucose culture conditions. Glomerular hyperfiltration is a characteristic change in the early stage of diabetic nephropathy. Treatment with aldose reductase inhibitor, which prevented glomerular hyperfiltration without changes in blood glucose levels, decreased ICAM-1 expression and mononuclear cell infiltration. Moreover, we examined the ICAM-1 expression in the glomeruli of the 5/6 nephrectomized rat, which is a model for glomerular hyperfiltration without hyperglycemia. The ICAM-1 expression and infiltration of mononuclear cells was significantly increased in the glomeruli of 5/6 nephrectomized rats. We conclude that ICAM-1 is upregulated and promotes the recruitment of mononuclear cells in diabetic glomeruli. Moreover, glomerular hyperfiltration that occurs in the early stage of diabetic glomeruli may be one of the potential mechanisms of ICAM-1 upregulation in diabetic nephropathy.

Increased expression of selectins in kidneys of patients with diabetic nephropathy

Summary 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. [Diabetologia (1998) 41: 185–192]

Distribution of extracellular matrix receptors in various forms of glomerulonephritis

Integrins are heterodimeric transmembrane receptor glycoproteins consisting of alpha and beta subunits that mediate adhesion and interactions between cells and extracellular matrix. Such interactions may be perturbed in various pathologic states, resulting in the altered phenotypic expressions of the integrins in affected tissues. To ascertain the alterations in integrins in various renal diseases, their distribution was investigated in different forms of glomerulonephritis by indirect immunofluorescence and immunoelectron microscopy using specific antibodies directed against beta 1 integrins and integrin alpha v beta 3 (vitronectin receptor). In addition, the distribution of certain extracellular matrix components (ie, fibronectin, vitronectin, and type IV collagen) was examined. Integrin beta 1 and alpha v beta 3 were highly expressed in proliferating mesangial cells in immunoglobulin A nephropathy, membranoproliferative glomerulonephritis type I and diffuse proliferative lupus nephritis. Their putative ligands (ie, fibronectin, vitronectin, and type IV collagen) also were increased in the expanded mesangial regions. In immunoglobulin A nephropathy, integrin beta 1 and alpha v beta 3 were seen by immunoelectron microscopy to be localized to the mesangial cell membranes in close proximity to the immune complex deposits; however, fibronectin and vitronectin immunoreactivities were observed in the mesangial immune complex deposits. Similarly, vitronectin also was detected in the immune complex deposits of other forms of proliferative nephritis, ie, membranoproliferative glomerulonephritis type I and diffuse proliferative lupus nephritis. In diffuse proliferative lupus nephritis, the cellular crescents displayed immunoreactivity toward integrin alpha v beta 3 and vitronectin. In nonimmune complex glomerular disease associated with nephrotic syndrome (ie, minimal change nephrotic syndrome), integrin alpha 3 beta 1, which normally has a linear capillary distribution, was decreased.(ABSTRACT TRUNCATED AT 250 WORDS)

Gene Expression of PDGF and PDGF Receptor in Various Forms of Glomerulonephritis

Platelet-derived growth factor (PDGF) is an important mitogenic factor for various cells. In order to elucidate the role of PDGF in the development of human glomerulonephritis, we examined the gene and protein expression of the PDGF-B chain (PDGF-B) and PDGF-beta receptor (PDGFR-beta) in renal biopsy specimens from patients with various forms of glomerulonephritis using a nonradioactive in situ hybridization and an immunohistochemical technique. The mRNA expression of PDGF-B and PDGFR-beta was significantly increased in the glomeruli of patients with mesangial proliferative glomerulonephritis (IgA nephropathy, Henoch-Schönlein purpura nephritis, and lupus nephritis) compared with those in normal glomeruli. In cases with increased protein expression of PDGF-B and PDGFR-beta, each mRNA expression was also increased. The degree of glomerular injury was positively correlated with the number of mRNA-positive cells for both PDGF and PDGF receptor. There was also a positive correlation between the number of mRNA-positive cells for PDGF-B and PDGFR-beta. PDGF-B and PDGFR-beta were also expressed on cells of the capillary wall, cellular crescents and infiltrated cells in the interstitium. The results suggest that PDGF acts as an important and common mediator for the development of various forms of human mesangial proliferative glomerulonephritis. Furthermore, PDGF may participate in crescent formation and tubulo-interstitial injury.

The critical role of intercellular adhesion molecule-1 in Masugi nephritis in rats

Intercellular adhesion molecule-1 (ICAM-1, CD54), an adhesion molecule of the immunoglobulin superfamily, is an endothelial cell surface ligand for such leukocyte integrins as lymphocyte-function-associated molecule 1 (LFA-1, CD11a/CD18), Mac-1 (CD11b/CD18) and CD43. These molecules mediate adhesive interactions between leukocytes and endothelial cells and are critically involved in infiltration of leukocytes into inflammatory lesions. We examined the expression of ICAM-1 in renal tissues of Masugi nephritis rats and directly examined the role of ICAM-1 by administration of neutralizing monoclonal antibodies (MAbs) to rat ICAM-1, LFA-1 alpha-subunit (LFA-1 alpha), beta-subunit (LFA-1 beta) and Mac-1 alpha-subunit (Mac-1 alpha). Within 3 h after injection of nephrotoxic serum, increased expression of ICAM-1 was detected in the glomeruli by in situ hybridization and an immunofluorescence study. Proteinuria was significantly suppressed by the MAbs against ICAM-1, Mac-1 alpha and LFA-1 beta. Neutrophil infiltration into the glomeruli was significantly prevented by injection of the MAbs against ICAM-1, LFA-1 alpha and LFA-1 beta. These results indicate that both ICAM-1/LFA-1 and ICAM-1/Mac-1 pathways are involved in neutrophil infiltration into the glomeruli. On the other hand, monocytic infiltration was prevented by the MAbs against ICAM-1, LFA-1 alpha and LFA-1 beta but not by anti-Mac-1 alpha MAb. Due to these results, ICAM-1 is considered to be a critical molecule involved in the pathogenesis of the leukocyte infiltration into the glomeruli in the heterologous phase of Masugi nephritis. Anti-ICAM-1 antibody may be beneficial in the treatment of leukocyte-mediated glomerular diseases.

Immunoreactivity of the JK-132 monoclonal antibody directed against basement membrane collagen in normal and diabetic glomeruli.

The possible involvement of basement membrane-associated collagen (recognized by the monoclonal antibody JK-132) in the evolution of diabetic nephropathy was studied in kidney specimens from seven patients with noninsulin-dependent diabetes mellitus, and its distribution was compared with those of antibodies against α1 to α4 chains of type IV collagen. JK-132, a monoclonal antibody against basement membrane-associated collagen, reacted immunohistochemically exclusively with the mesangial matrix of the glomerular capillary. In contrast, antibodies to the α1 and α2 chains (IV) reacted strongly with mesangial matrix, and less strongly with the glomerular basement membrane (GBM). Antibodies to the α3 and α4 chains (IV) reacted mainly with GBM. In diabetes, JK-132 reacted most extensively with the expanded mesangial matrix, its staining intensity increasing with progression of the diabetic glomerulosclerosis. Antibodies to the α1 and α2 chains (IV) reacted prominently with the expanded mesangial matrix but less strongly with the GBM. Antibodies to the α3 and α4 chains reacted intensely with the thickened GBM. These results suggest that basement membrane-associated collagen differs from α1 to α4 chains of type IV collagen and that basement membrane-associated collagen is a good marker of mesangial expansion in diabetic nephropathy.