(1/2477) T lymphocyte adhesion mechanisms within inflamed human kidney: studies with a Stamper-Woodruff assay.
Renal inflammatory conditions are characterized by mononuclear cell recruitment to sites of inflammation. We have developed a modified Stamper-Woodruff assay system to analyze mechanisms of functional T cell adhesion to cryostat sections of renal biopsy material from patients with vasculitic glomerulonephritis (GN) and acute allograft rejection. Peripheral blood T cells adhered to intraglomerular, periglomerular, and tubulointerstitial regions of the cortex. Blocking monoclonal antibodies against tissue expressed ICAM-1, VCAM-1, and the CS-1 domain of fibronectin (CS-1Fn) differentially attenuated T cell adhesion. Glomerular adhesion in vasculitic GN and tubulointerstitial adhesion in acute rejection were particularly sensitive to both anti-ICAM-1 and anti-VCAM-1 antibodies, indicating a prominent role for ICAM-1 and VCAM-1 at glomerular sites in vasculitis and at tubulointerstitial sites in rejection. Furthermore, using KL/4 cells (LFA-1 expressing) and Jurkat cells (VLA-4 expressing), we demonstrated specific LFA-1/ICAM-1- and VLA-4/VCAM-1-mediated interactions within glomerular and tubulointerstitial compartments. Jurkat cells also adhered to VCAM-1-free sites, and binding was inhibitable by anti-CS-1Fn antibody, thereby demonstrating a role for VLA-4/fibronectin interactions especially at intraglomerular sites in acute rejection where VCAM-1 is notably absent. We therefore propose a prominent functional role for ICAM-1, VCAM-1, and CS-1 domain fibronectin in T cell recruitment to the inflamed kidney. (+info)
(2/2477) Interleukin-8: A pathogenetic role in antineutrophil cytoplasmic autoantibody-associated glomerulonephritis.
BACKGROUND: In neutrophil trafficking, the role of interleukin-8 (IL-8) is location dependent. Tissue IL-8 directs transmigration, whereas intravascular IL-8 frustrates this process. The bystander damage of glomerular endothelium by antineutrophil cytoplasmic autoantibody (ANCA)-activated neutrophils is believed to be an early event in the pathogenesis of ANCA-associated glomerulonephritis. We have studied the role of IL-8 in this process. METHODS: Intraglomerular expression of IL-8 in patients with ANCA-associated glomerulonephritis was studied by in situ hybridization and immunohistochemistry and location of neutrophils by serial section immunohistochemistry. In vitro, we analyzed ANCA-stimulated neutrophil IL-8 production by enzyme-linked immunosorbent assay, and the IL-8 attributable effect of ANCA-stimulated neutrophil supernatant by chemotactic and transendothelial assays. RESULTS: There was intraglomerular expression of IL-8 at segmental, crescentic, and parietal epithelial sites. IL-8 protein expression colocalized to intraglomerular neutrophils; many localized within glomerular capillary loops, suggesting failed trafficking to tissue IL-8. ANCAs differentially stimulated time- and dose-dependent neutrophil IL-8 production, and ANCA-stimulated neutrophil supernatant demonstrated potent IL-8-dependent chemotactic activity and inhibited transendothelial migration of normal human neutrophils toward an IL-8 gradient. CONCLUSION: Despite heavy tissue expression of IL-8 in ANCA-associated GN, the production of IL-8 by ANCA-stimulated neutrophils within the intravascular compartment may frustrate neutrophil transmigration, encourage intravascular stasis, and contribute to bystander damage of glomerular endothelial cells. (+info)
(3/2477) Up-regulation of glomerular extracellular matrix and transforming growth factor-beta expression in RF/J mice.
BACKGROUND: RF/J mice were first reported as a murine model of spontaneous glomerulosclerosis by Gude and Lupton in 1960, but the precise histologic characteristics and immunopathological background of this mouse have not been investigated further. METHODS: Measurements of serum levels of immunoglobulins, anti-single strand DNA (anti-ss-DNA) antibody, complement (C3), and circulating immune complex (IC) were performed. Analyses of glomerular histological and immunopathological lesions in association with the detection of mRNA expression of collagen IV, TGF-beta, matrix protein turnover related enzymes, matrix metalloproteinase-2 (MMP-2), tissue inhibitor of metalloproteinase-2 (TIMP-2) and platelet-derived growth factor (PDGF) were also performed in young (10-week-old) and elderly (60-week-old) RF/J mice with age-matched BALB/C mice as the controls. RESULTS: High levels of serum IgA and IgG from as early as 20 weeks of age were noted in the RF/J mice. Serum anti-ss-DNA antibody of aged RF/J mice increased up to 23% of that of aged MRL-lpr/lpr mice, and serum C3 concentration significantly decreased with age, reaching lower levels than that of BALB/c mice. IgA-IC levels were significantly high compared to BALB/C mice both in the early and late stages of life, whereas IgG-IC levels were high only in mice younger than 20 weeks. Semiquantitative and quantitative analyzes of renal histopathological findings revealed significantly marked and age-related mesangial matrix expansion in RF/J mice, with increasing frequency of global glomerular sclerosis and tubulointerstitial damage. On the other hand, although precise measurements of glomerular cell numbers also showed an apparent augmentation in both young and old RF/J mice compared to BALB/C mice, glomerular cellularity decreased with age in RF/J mice. Immunohistochemical study revealed massive immunoglobulin deposition from a young age in association with significantly higher accumulation of matrix proteins, such as types I and IV collagen and laminin from the early stage of life. In addition, in these glomeruli, transforming growth factor-beta1 (TGF-beta1) was highly expressed both in young and old mice. The mRNA expression of MMP-2 was up-regulated only in the early stage of life. Although PDGF mRNA of RF/J mice was significantly up-regulated in the early stage of life, the differences between the mice disappeared in the late stage of life. CONCLUSIONS: These findings suggest that in RF/J mice, an immunopathological background inducing high serum immunoglobulin and IC levels from the early stage of life is closely related to mesangioproliferative glomerular lesions mediated by PDGF, and that development of massive extracellular matrix accumulation in glomeruli was induced by up-regulated expression of TGF-beta with inappropriate regulation of protein turnover-related enzyme production. (+info)
(4/2477) Cytokine network and resident renal cells in glomerular diseases.
This review has highlighted the cytokine network which is involved in renal damage from an initial, even transient, stage to extensive glomerular and tubulointerstitial sclerosis. Studies of a variety of different proliferative glomerulonephritides have documented the prominent role of macrophages in infiltrating mesangium, subendothelial area and crescentic formation. Thus, they stimulate crescent glomerular cells to produce other cytokines and growth factors. The identification of other mediators, released by the monocytes in the interstitium, exemplifies the important role of these cells in progressive interstitial scarring through the release of fibrogenic cytokines. In addition, renal tubular cells have been found to produce a vast array of cytokines and growth factors which participate in the generation of renal interstitial scarring. (+info)
(5/2477) Incidence of analgesic nephropathy in Berlin since 1983.
BACKGROUND: Phenacetin was removed from the German market in 1986 and was replaced mainly in analgesic compounds by acetaminophen. Our objective was to examine the effect of this measure on the incidence of analgesic nephropathy in light of the changes in other end-stage renal diseases. METHODS: We therefore compared the proportion of renal diseases in all patients starting dialysis treatment during three 18-month periods: 4/1982-9/1983 (n=57); 1/1991-6/1992 (n=81); and 10/1995-3/1997 (n=76). RESULTS: On the one hand, the proportion of end-stage analgesic nephropathy decreased significantly from 30% in 1981-1982 to 21% in 1991-1992 and 12% in 1995-1997 (P=0.01). On the other hand, type II diabetes increased significantly from 7% to 22% (P=0.01) and 29%, (P=0.001). Using the chi2 distribution test to analyze the frequencies of seven diseases at three different time intervals, however, showed that the changes in renal-disease proportions between 1982-1983, 1991-1992 and 1995-1997 were not significantly independent. There was a significant median age increase from 52 years (CI0.95 44-58) in 1982-1983 to 63 (CI0.95 55-67) in 1991-1992 and 63 (CI0.95 60-66) in 1995-1997 (P=0.003) for all patients starting dialysis but not for those with analgesic nephropathy [59 (55-71) vs 64 (53-67) and 61 (50-72); n.s.]. CONCLUSION: The decrease of end-stage analgesic nephropathy since 1983 may be partially due to the removal of phenacetin from the German market in 1986. However, considering the general increase in numbers of dialysis patients, their higher age and the increased incidence of type II diabetes, the decrease in analgesic nephropathy is not a statistically significant independent variable. Altered admittance policies for dialysis treatment have yielded a new pattern of renal-disease proportion which interferes with changes in the incidence of analgesic nephropathy. (+info)
(6/2477) Prominence of cell-mediated immunity effectors in "pauci-immune" glomerulonephritis.
The majority of patients with rapidly progressive crescentic glomerulonephritis show histologic features of extensive necrosis and focal and segmental proliferation with fibrin production, but little or absent Ig deposition in the glomerulus. This subcategory of the disease, labeled "pauci-immune" glomerulonephritis, has recently been shown to be associated with the presence of antineutrophil cytoplasmic antibody in the patient's circulation (but not within the glomerulus). The absence of the effectors of humoral immunity at the site of renal injury led to this investigation of the contribution of cell-mediated immunity to the glomerular injury in this form of glomerulonephritis. In 15 patients presenting acutely with pauci-immune glomerulonephritis, CD3-positive T cells (3.7+/-2.5 [mean +/- SD] cells per glomerular cross section, [c/gcs]), CD45RO-positive T cells (2.7+/-1.9 c/cgs), macrophages (7.3+/-6.1 c/gcs), fibrin (3+), and endothelial-associated tissue factor were demonstrated to be prominent in glomeruli. These mediators were absent in a group of 12 patients with thin basement membrane disease and only occasionally observed in a group of eight patients with "humorally mediated"(noncrescentic) glomerulonephritis. Thus, in pauci-immune glomerulonephritis, there is the development of significant cell-mediated immunity with activated T cells, macrophages, tissue factor, and fibrin at the site of glomerular injury, suggesting that this glomerular disease is most likely a manifestation of T cell-directed cognate immune injury. (+info)
(7/2477) Role of xanthine oxidase in passive Heymann nephritis in rats.
Passive Heymann nephritis (PHN) in rats is a model of human membranous nephropathy characterized by formation of subepithelial immune deposits in the glomerular capillary wall and complement activation. Oxygen radicals have been implicated in the subsequent glomerular damage which leads to proteinuria. This study examines the involvement of xanthine oxidase in this process. Xanthine oxidase activity was increased nearly twofold in glomeruli isolated 1 and 12 d after induction of PHN, and this was associated with increased glomerular superoxide anion generation. Analysis of glomerular samples by Northern and Western blotting revealed no quantitative changes in xanthine oxidoreductase expression in PHN, suggesting conversion of xanthine dehydrogenase to the oxidase form as the cause of increased activity. Treatment of rats with tungsten, an inhibitor of xanthine oxidase, before induction of PHN resulted in a marked decrease in glomerular xanthine oxidase activity and superoxide anion generation, and decreased proteinuria by 80% (day 12: 423+/-245 mg/d in PHN versus 78+/-53 mg/d in tungsten-treated PHN animals, P < 0.01). These findings point to a pivotal role of xanthine oxidase in the pathophysiology of PHN and could be of importance in the therapy of human membranous nephropathy. (+info)
(8/2477) Angiotensin II receptor type 1 gene expression in human glomerulonephritis and diabetes mellitus.
The renin-angiotensin system plays an important role in the progression of chronic renal disease. Although the expression of renin and angiotensin-converting enzyme in experimental and human renal disease has been well characterized, no information is available regarding human angiotensin type 1 (AT1) receptor expression. The net effect of renin depends on AT1 receptor expression, among other factors. Receptor expression was determined in renal biopsy samples (including all tissue components) and isolated glomeruli from patients with glomerulonephritis (GN) or diabetic nephropathy (non-insulin-dependent diabetes mellitus). Biopsy samples and isolated glomeruli from tumor-free tissue from tumor nephrectomies served as controls. Human AT1 receptor gene expression was determined by quantitative reverse transcription-PCR, using an AT1 receptor deletion mutant as the internal standard. In whole biopsy samples from 37 patients with various types of GN, AT1 receptor mRNA levels were lower, compared with nine control biopsy samples (P < 0.001). AT1 receptor mRNA levels were also significantly lower (P < 0.001) in eight samples from patients with diabetic nephropathy. In microdissected glomeruli, AT1 receptor gene expression was significantly lower in samples from patients (n = 22) with various types of GN, compared with 12 microdissected tumor nephrectomy control samples (P < 0.0023). It is concluded that AT1 receptor mRNA expression is low in glomeruli of patients with chronic renal disease. This may reflect a regulatory response to (inappropriately) high intrarenal angiotensin II concentrations. (+info)