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ANCA-associated vasculitis is the most frequent cause of crescentic GN. To define new molecular and/or cellular biomarkers of this disease in the kidney, we performed microarray analyses of renal biopsy samples from patients with ANCA-associated crescentic GN. Expression profiles were correlated with clinical data in a prospective study of patients with renal ANCA disease. CC chemokine ligand 18 (CCL18), acting through CC chemokine receptor 8 (CCR8) on mononuclear cells, was identified as the most upregulated chemotactic cytokine in patients with newly diagnosed ANCA-associated crescentic GN. Macrophages and myeloid dendritic cells in the kidney were detected as CCL18-producing cells. The density of CCL18(+) cells correlated with crescent formation, interstitial inflammation, and impairment of renal function. CCL18 protein levels were higher in sera of patients with renal ANCA disease compared with those in sera of patients with other forms of crescentic GN. CCL18 serum levels were higher in patients who suffered from ANCA-associated renal relapses compared with those in patients who remained in remission. Using a murine model of crescentic GN, we explored the effects of the CCL18 murine functional analog CCL8 and its receptor CCR8 on kidney function and morphology. Compared with wild-type mice, Ccr8(-/-) mice had significantly less infiltration of pathogenic mononuclear phagocytes. Furthermore, Ccr8(-/-) mice maintained renal function better and had reduced renal tissue injury. In summary, our data indicate that CCL18 drives renal inflammation through CCR8-expressing cells and could serve as a biomarker for disease activity and renal relapse in ANCA-associated crescentic GN., (Copyright © 2015 by the American Society of Nephrology.)

Neutrophil trafficking to sites of inflammation is essential for the defense against bacterial and fungal infections, but also contributes to tissue damage in TH17-mediated autoimmunity. This process is regulated by chemokines, which often show an overlapping expression pattern and function in pathogen- and autoimmune-induced inflammatory reactions. Using a murine model of crescentic GN, we show that the pathogenic TH17/IL-17 immune response induces chemokine (C-X-C motif) ligand 5 (CXCL5) expression in kidney tubular cells, which recruits destructive neutrophils that contribute to renal tissue injury. By contrast, CXCL5 was dispensable for neutrophil recruitment and effective bacterial clearance in a murine model of acute bacterial pyelonephritis. In line with these findings, CXCL5 expression was highly upregulated in the kidneys of patients with ANCA-associated crescentic GN as opposed to patients with acute bacterial pyelonephritis. Our data therefore identify CXCL5 as a potential therapeutic target for the restriction of pathogenic neutrophil infiltration in TH17-mediated autoimmune diseases while leaving intact the neutrophil function in protective immunity against invading pathogens., (Copyright © 2015 by the American Society of Nephrology.)

Interleukin-17A (IL-17) promotes inflammatory renal tissue damage in mouse models of crescentic glomerulonephritis, including murine experimental autoimmune anti-myeloperoxidase glomerulonephritis, which most likely depends on IL-17-producing Th17 cells. In human anti-neutrophil cytoplasmic antibody (ANCA)-associated glomerulonephritis, however, the cellular sources of IL-17 remain to be elucidated. Therefore, we analyzed human kidney biopsies of active necrotizing and crescentic ANCA-associated glomerulonephritis by immunohistochemistry using an IL-17-specific antibody and by immunofluorescent colocalization with cell type markers. We detected numerous IL-17-expressing (IL-17(+)) cells in the glomeruli and in the tubulointerstitium. Unexpectedly, most of these IL-17(+) cells were polymorphonuclear neutrophilic granulocytes, while IL-17(+) T cells and IL-17(+) mast cells were present at significantly lower frequencies. IL-17 was not detected in other infiltrating or resident kidney cells. In those patients who had not received immunosuppressive treatment before biopsy, serum creatinine levels were positively correlated with tubulointerstitial IL-17(+) neutrophils as well as IL-17(+) T cells. Furthermore, we could demonstrate that purified human blood neutrophils expressed IL-17 protein and released it upon stimulation in vitro. In conclusion, these results support a pathogenic role for IL-17 in human ANCA-associated glomerulonephritis. Our data suggest that in the acute stage of the disease neutrophils may act as an important immediate-early innate source of IL-17 and may thereby initiate and promote ongoing renal inflammation. IL-17 may thus be a target for treating acute ANCA-associated glomerulonephritis.

In renal tissue injury, activation of the transcription factor NF-kappaB has a central role in the induction of proinflammatory gene expression, which are involved in the development of progressive renal inflammatory disease. The function of NF-kappaB during the switch from the inflammatory process toward resolution, however, is largely unknown. Therefore, we assessed the time-dependent activation and function of NF-kappaB in two different models of acute nephritis. Our experiments demonstrate a biphasic activation of NF-kappaB in the anti-Thy-1 model of glomerulonephritis in rats and the LPS-induced nephritis in mice, with a first peak during the induction phase and a second peak during the resolution period. After induction of glomerular immune injury in rats, predominantly NF-kappaB p65/p50 heterodimer complexes are shifted to the nucleus whereas during the resolution phase predominantly p50 homodimers could be demonstrated in the nuclear compartment. In addition, we could demonstrate that p50 protein plays a pivotal role in the resolution of LPS-induced renal inflammation since NF-kappaB p50 knockout mice demonstrate significantly higher chemokine expression, prolonged renal inflammatory cell infiltration with consecutive tissue injury, and reduced survival. In conclusion, our studies indicate that NF-kappaB subunit p50 proteins have critical in vivo functions in immunologically mediated renal disease by downregulating inflammation during the resolution period.

The chemokine receptor CCR5 is predominantly expressed on monocytes and Th1-polarized T cells, and plays an important role in T cell and monocyte recruitment in inflammatory diseases. To investigate the functional role of CCR5 in renal inflammation, we induced a T cell-dependent model of glomerulonephritis (nephrotoxic serum nephritis) in CCR5(-/-) mice. Induction of nephritis in wild-type mice resulted in up-regulation of renal mRNA expression of the three CCR5 chemokine ligands, CCL5 (15-fold), CCL3 (4.9-fold), and CCL4 (3.4-fold), in the autologous phase of the disease at day 10. The up-regulated chemokine expression was paralleled by infiltration of monocytes and T cells, followed by renal tissue injury, albuminuria, and loss of renal function. Nephritic CCR5(-/-) mice showed a 3- to 4-fold increased renal expression of CCL5 (61.6-fold vs controls) and CCL3 (14.1-fold vs controls), but not of CCL4, in comparison with nephritic wild-type mice, which was accompanied by augmented renal T cell and monocyte recruitment and increased lethality due to uremia. Furthermore, CCR5(-/-) mice showed an increased renal Th1 response, whereas their systemic humoral and cellular immune responses were unaltered. Because the CCR5 ligands CCL5 and CCL3 also act via CCR1, we investigated the effects of the pharmacological CCR1 antagonist BX471. CCR1 blockade in CCR5(-/-) mice significantly reduced renal chemokine expression, T cell infiltration, and glomerular crescent formation, indicating that increased renal leukocyte recruitment and consecutive tissue damage in nephritic CCR5(-/-) mice depended on functional CCR1. In conclusion, this study shows that CCR5 deficiency aggravates glomerulonephritis via enhanced CCL3/CCL5-CCR1-driven renal T cell recruitment.

The recruitment of inflammatory cells into renal tissue, mainly T cells and monocytes, is a typical feature of various renal diseases such as glomerulonephritis, thrombotic angiopathies, allograft rejection, and vasculitis. T cells predominantly infiltrate the tubulointerstitium, whereas monocytes are present in the tubulointerstitial and glomerular compartment. Because chemokines play a pivotal role in leukocyte trafficking under inflammatory conditions, this study investigated whether a differential expression of chemokines contributes to the precise coordination of leukocyte subtype trafficking in a rat model of renal microvascular endothelial injury. Renal microvascular endothelial injury was induced in rats by selective renal artery perfusion with an anti-endothelial antibody. Induction of the disease led to severe glomerular and tubulointerstitial endothelial injury with subsequent upregulation of chemokines followed by inflammatory cell recruitment. Among the analyzed chemokine mRNA, IP-10/CXCL10 (119-fold), acting via CXCR3 on activated T cells, and MCP-1/CCL2 (65-fold), acting via CCR2 on monocytes, were by far the most strongly upregulated chemokines. In situ hybridization revealed that IP-10/CXCL10 mRNA was selectively expressed by endothelial cells in the tubulointerstitial area, co-localizing with infiltrating T cells. Despite extensive damage of glomerular vasculature, no IP-10/CXCL10 expression by glomerular endothelial cells was detected. MCP-1/CCL2 mRNA in contrast was detectable in the glomerulus and the tubulointerstitium. Treatment with a neutralizing anti-IP-10/CXCL10 antibody significantly reduced the number of infiltrating tubulointerstitial T cells without affecting monocyte migration and led to an improved renal function. Our study demonstrates a role of IP-10/CXCL10 on T cell recruitment in a rat model of renal endothelial microvascular injury. Furthermore, a differential chemokine expression profile by endothelial cells in different renal compartments was found. These findings are consistent with the hypothesis that functional heterogeneity of endothelial cells from different vascular sites exists and provide an insight into the molecular mechanisms that may mediate compartment-specific T cell and monocyte recruitment in inflammatory renal disease.

We report on successful induction of remission in a patient with necrotizing crescentic glomerulonephritis associated with myeloperoxidase-antineutrophil-cytoplasm antibodies by primary use of the anti-tumor necrosis factor (TNF)-alpha chimeric monoclonal antibody infliximab in combination with corticosteroids only. The standard treatment containing cyclophosphamide has reduced the former high mortality from systemic vasculitides. However, the toxicity of this alkylating agent limits its long-term use. As TNF-alpha has been shown to play a central pathogenic role in vasculitis as well as in crescentic glomerulonephritis, anti-TNF-alpha treatment in combination with cyclophosphamide has been found to be effective in therapy-resistant vasculitis. Previous reports on TNF-alpha-blocking therapies without additional cyclophosphamide did not include patients with active and severe crescentic glomerulonephritis. As our patient refused cyclophosphamide, he was given four infusions of infliximab (4 mg/kg on weeks 0, 2, 6 and 10) and methylprednisolone pulses (1 g on days 1-3), followed by daily oral prednisolone (starting with 2 mg/kg and tapering down to 5 mg daily within 3 months). After 12 weeks, control biopsy demonstrated lack of active glomerular inflammation while initially reduced renal function (creatinine 271 versus 172 mol/l, clearance 26 versus 62 ml/min) and proteinuria (2.4 versus 1.0 g/d) improved. Under remission maintenance therapy with azathioprine and prednisolone, the patient showed no relapses during a 1-year follow-up. Finally we demonstrate that there might be patients with crescentic glomerulonephritis who do not require therapy with alkylating substances and that less toxic agents such as the TNF-alpha-blocking monoclonal antibody infliximab could play a role in future primary treatment of crescentic glomerulonephritis.

Background: Chemokines are involved in the regulation of the cellular renal infiltrate in glomerulonephritis; however, it is unclear to which degree resident glomerular cells or infiltrating leukocytes contribute to the formation of chemokines in glomerular inflammatory lesions. We therefore examined whether monocytes/macrophages play a role in the expression of the C-C chemokines MCP-1/CCL2 and RANTES/CCL5 in renal tissue in a lipopolysaccharide (LPS)-induced model of inflammation, where previously we have shown increased glomerular RANTES expression and glomerular infiltration of ED-1-positive cells., Methods: Inflammatory lesions were induced by an intraperitoneal injection of LPS. The infiltration of monocytes into the glomerulus was reduced by two experimental approaches. First, rats were depleted of monocytes by the use of specific monocyte-antisera or by cytotoxic drugs. Second, the infiltration of monocytes into the kidney was reduced by using intercellular adhesion molecule-1 (ICAM-1) knockout mice., Results: Both experimental approaches demonstrated a significant reduction in the number of infiltrating monocytes/macrophages after lipopolysaccharide injection. This reduction in the infiltration of inflammatory cells was associated with significantly reduced RANTES/CCL5 mRNA expression. However, MCP-1/CCL2 mRNA expression was not inhibited after the LPS injection by monocyte/macrophage depletion. Also, the increase in nuclear factor-kappaB (NF-kappaB) binding activity after the LPS injection was not reduced in pretreated animals. The experiments therefore demonstrate that infiltrating monocytes/macrophages contribute to increased RANTES/CCL5 mRNA expression in inflammatory renal lesions, whereas MCP-1/CCL2 mRNA expression and NF-kappaB activation were not reduced by monocyte/macrophage depletion., Conclusion: MCP-1/CCL2 released from renal tissue upon stimulation plays a major role in the regulation of monocyte/macrophage infiltration, which contributes significantly to increased renal RANTES/CCL5 expression. This cross-talk between resident renal cells and monocytes/macrophages is therefore likely to boost the number of infiltrating inflammatory cells.

Most cases of fibrillary glomerulonephritis (FG) terminate in end-stage renal disease within a few years. We report on two female patients (41 and 50 years old) with the diagnosis of FG associated with crescentic glomerulonephritis, a combination found in 20% to 25% of cases of FG. A broad spectrum of infectious disease and systemic immunologic disorders could be ruled out by specific assays. Both patients had severely impaired renal function, nephrotic syndrome, and hypertension. Based on the biopsy finding with necrotizing FG, treatment was started with corticosteroids and cyclophosphamide. In both patients, renal function recovered markedly within 6 months of treatment, in one case remaining stable for 3.5 years. Whether or not cyclophosphamide treatment changed the course of the FG itself or counteracted the acute crescentic process cannot be determined from these two patients. Based on these promising preliminary findings and the poor prognosis of FG, however, we recommend cyclophosphamide treatment of patients with FG and additional crescentic glomerulonephritis. For a systematic evaluation of the therapeutic options in FG, a multicenter clinical trial should be conducted., (Copyright 2002 by the National Kidney Foundation, Inc.)

Intensive immunosuppressive therapy has improved the outcome of patients with rapidly progressive glomerulonephritis (RPGN), which progresses to end-stage renal failure in 90% of patients without intervention. However, it remains unclear which patients benefit most from immunosuppressive therapy and whether plasmapheresis improves long-term outcome. This prospective multicenter study randomized 39 patients with biopsy-proven RPGN (Couser type II, n = 6; pauci-immune type III, n = 33) to undergo either immunosuppressive therapy with prednisone and cyclophosphamide (n = 18) or plasmapheresis in addition to immunosuppression (n = 21). Patients were observed for a mean of 127 months or until reaching the end points of hemodialysis or death. Six of 11 patients who were initially dialysis dependent recovered renal function; however, 2 of those patients required dialysis therapy again after 10 and 105 months. Overall, 15 of 39 patients reached end-stage renal failure after a mean of 25 months, and 4 patients died before requiring hemodialysis therapy. Plasmapheresis had no significant effect on renal or patient survival in type II or pauci-immune (type III) RPGN, independently of age, sex, or serum creatinine level at the time of diagnosis. Overall, probabilities of dialysis-free survival were 0.80, 0.67, 0.55, and 0.48 after 12, 24, 60, and 120 months, respectively. Histological characteristics at the time of diagnosis predicted the effect of immunosuppression on renal outcome. All patients were dialysis dependent within 24 months if more than one third of glomeruli were totally sclerosed on the initial histological examination. Interstitial fibrosis also correlated significantly with the risk for progression to renal failure. Conversely, long-term dialysis-free survival was significantly more likely in patients with a greater number of crescents than in those with a low number of crescents. In conclusion, plasmapheresis does not add to the improvement in outcome reached by immunosuppression alone. Crescents on initial histological examination correlate with a favorable outcome. However, 90% of patients who initially have glomerular sclerosis present become dialysis dependent. Overall, approximately 50% of patients are alive and off dialysis therapy 10 years after the diagnosis of type II or type III RPGN using immunosuppression with cyclophosphamide and prednisone., (Copyright 2002 by the National Kidney Foundation, Inc.)

Background: This study evaluated the mechanisms of monocyte/macrophage (M/M) infiltration in a rat model of anti-glomerular basement membrane glomerulonephritis (GN). We focused on chemokines and osteopontin, which are known regulators of M/M recruitment., Methods: Using immunohistology, in situ hybridization, and Northern blotting, the expression levels of chemokines and osteopontin were evaluated in isolated glomeruli and tubules 4, 10, and 20 days after the induction of GN. In vivo blocking experiments were performed by application of neutralizing antibodies against osteopontin and monocyte chemoattractant protein-1 (MCP-1)., Results: In nephritic animals, high glomerular MCP-1 and RANTES (regulated upon activation normal T cell expressed and secreted) expression levels were observed on days 4 and 10. The tubular expression of MCP-1, however, was only slightly enhanced. In contrast, tubular osteopontin production was maximally stimulated (day 10) and paralleled with peaks of albuminuria and tubulointerstitial M/M infiltration. Application of an anti-osteopontin antibody ameliorated tubulointerstitial and glomerular M/M recruitment, whereas treatment with an anti-MCP-1 antibody selectively reduced glomerular M/M recruitment. However, tubulointerstitial M/M infiltration remained unchanged., Conclusion: These studies show that chemokines and osteopontin are differentially expressed in glomeruli and tubules in this model of GN. Chemokines play a primary role in the glomeruli, whereas osteopontin has a predominant role in tubulointerstitial M/M recruitment. The roles of chemokines and osteopontin may thus be dependent on the renal compartment and on the disease model.

Background: Resident glomerular cell proliferation, matrix deposition and secretion of matrix metalloproteinases play a major role in the progression of chronic glomerular disease. These features were studied in a novel approach in a rat model of chronic glomerulonephritis induced by four injections of an anti-Thy 1.1 antiserum at weekly intervals., Methods: Chronic immune mediated mesangial injury was induced in male Sprague-Dawley rats by repeated intravenous injection of an anti-Thy 1.1 antiserum. One week after the first and fourth injection of the antiserum proteinuria was evaluated and the kidneys were removed. Immunohistology was performed for proliferating cells, monocytes and collagen type IV. Furthermore, mRNA expression of collagen type IV, TGF-beta and the matrix degrading enzyme MMP-2 as well as MMP-2 protein expression were studied., Results: Urinary protein excretion was dramatically increased after one antiserum injection and stayed elevated at a lower level after the fourth antiserum injection. After the initial induction of nephritis, 7 days following antiserum, resident glomerular cell proliferation was increased whereas with repeated injections of the antiserum cell numbers were not different from controls, as measured 1 week after the fourth injection. In contrast, extracellular matrix accumulation (collagen type IV) increased after the first antiserum injection and further increased after the fourth antiserum injection. The mRNA expression for collagen type IV increased after the first antiserum injection and showed further increase after the fourth antiserum injection. Induction of nephritis also stimulated glomerular mRNA expression of MMP-2 and TGF-beta, both of which remained at a high level after the fourth antiserum injection. Glomerular protein levels of MMP-2 also increased after the first antiserum injection and showed a further slight increase after the fourth injection., Conclusion: Increased cellular proliferation is involved in an early stage of this disease, while enhanced expression of glomerular matrix and augmented mRNA and protein expression of the matrix degrading enzyme MMP-2 continue into the chronic phase, and contribute to the extensive structural remodeling process that accompanies this form of glomerular injury.

Systemic hypertension is a major risk factor that determines the rate of progression of kidney disease. The underlying mechanisms, however, are incompletely understood. To gain insight into these mechanisms, the present study was undertaken to characterize the effects of renovascular hypertension on the course of anti-thymocyte antibody-induced glomerulonephritis. Glomerulonephritis was induced in rats 6 weeks after the initiation of two-kidney, one-clip hypertension, when blood pressure was already increased. Structure and function of the clipped and the nonclipped kidney were examined 5 days later. Glomerular filtration rate (GFR) was measured by inulin clearance. The induction of nephritis did not alter the blood pressure in either hypertensive rats or normotensive controls. Albuminuria increased slightly in normotensive rats after the induction of nephritis, whereas no significant differences were found between hypertensive rats with or without nephritis. No significant differences were found for the GFR values of normotensive controls and nephritic animals or for values in the clipped kidney with or without nephritis. However, the GFR of the nonclipped kidney was significantly reduced in nephritic animals as compared with all other groups. Morphologic evaluation revealed that hypertensive rats with nephritis exhibited a combination of characteristics of nephritis and hypertensive glomerular injury. Histologic findings of nephritis, such as glomerular binding of rabbit IgG and glomerular proliferation and mesangial matrix expansion, were similar after the induction of nephritis in controls and in the clipped and nonclipped kidneys of hypertensive animals. However, intraglomerular microaneurysms were significantly more often found in the non-clipped kidneys after the induction of nephritis. Hypertension-induced deterioration of glomerular function was not associated with marked morphologic deterioration but rather with a combination of the characteristics of nephritis and hypertensive glomerular injury.

Background: Monocyte chemoattractant protein-1 (MCP-1) plays a significant role in the recruitment of monocytes/macrophages in experimental glomerulonephritis (GN). Because recent evidence points to possible profibrogenic effects of leukocyte-derived factors in GN, this study was designed to evaluate the role of the chemokine MCP-1 in the fibrogenesis of experimental GN., Methods: Rats with an anti-thy-1-induced GN were treated with a neutralizing antiserum against MCP-1. Glomerular collagen type IV, as a marker of glomerular matrix deposition, was assessed by Northern and Western blotting and immunohistology. Transforming growth factor-beta (TGF-beta), an important mediator of this matrix expansion, was studied by Northern and Western blotting., Results: The induction of GN resulted in a significant increase of glomerular collagen type IV deposition and TGF-beta synthesis. The neutralization of MCP-1 significantly reduced the enhanced collagen type IV protein synthesis and deposition without affecting collagen mRNA expression. However, both the enhanced transcription and protein synthesis of TGF-beta were inhibited by anti-MCP-1 antiserum in nephritic animals., Conclusions: In this model of GN, MCP-1 has a fibrogenic effect through the stimulation of TGF-beta. MCP-1 is thus not only important for the recruitment of inflammatory cells, but also mediates glomerular matrix accumulation.

Background: Monocyte chemoattractant protein-1 (MCP-1) has been shown to play a significant role in the recruitment of monocytes/macrophages in experimental glomerulonephritis. Whereas a number of inflammatory mediators have been characterized that are involved in the expression of MCP-1 in renal disease, little is known about repressors of chemokine formation in vivo. We hypothesized that cyclooxygenase (COX) products influence the formation of MCP-1 and affect inflammatory cell recruitment in glomerulonephritis., Methods: The effect of COX inhibitors was evaluated in the antithymocyte antibody model and an anti-glomerular basement membrane model of glomerulonephritis. Rats were treated with the COX-1/COX-2 inhibitor indomethacin and the selective COX-2 inhibitors meloxicam and SC 58125. Animals were studied at 1 hour, 24 hours, and 5 days after induction of the disease., Results: Indomethacin, to a lesser degree the selective COX-2 inhibitors, enhanced glomerular MCP-1 and RANTES mRNA levels. Indomethacin enhanced glomerular monocyte chemoattractant activity an the infiltration of monocytes/macrophages at 24 hours and 5 days., Conclusions: Our studies demonstrate that COX products may serve as endogenous repressors of MCP-1 formation in experimental glomerulonephritis. The data suggest that COX-1 and COX-2 products mediate these effects differently because the selective COX-2 inhibitors had less influence on chemokine expression.

Chemokines are a family of chemotactic cytokines whose participation in inflammation in vivo remains to be established. To study the role of monocyte-chemoattractant-protein-1 (MCP-1) on the glomerular accumulation of leukocytes, rats received a neutralizing anti-MCP-1 antiserum following the induction of an glomerulonephritis by an anti-thymocyte antibody (ATS). The infiltration of monocytes/macrophages (M/M) and granulocytes was analyzed by immunohistology. When studied by Northern blotting, glomerular mRNA levels of MCP-1, and interleukin 1 beta (IL-1 beta) increased at three hours and 24 hours following the induction of the injury. The glomerular mRNA expression of intercellular adhesion molecule-1 (ICAM-1) only increased marginally, whereas the expression of the chemokine RANTES was not enhanced. In animals that received anti-MCP-1 antibody glomerular MCP-1 mRNA expression increased. However, the chemoattractant activity for monocytes released into supernatants of isolated glomeruli was reduced. The anti-MCP-1 antibody did not affect glomerular IL-1 beta, ICAM-1 or RANTES mRNA levels. The induction of glomerulonephritis was associated with an increased glomerular recruitment of polymorphonuclear granulocytes (PMNs) at three hours and M/M at 24 hours, when compared with controls. The anti-MCP-1 antiserum significantly reduced the glomerular M/M infiltration at 24 hours by 40%, but was without effect on glomerular PMN recruitment or growth of the resident glomerular cells. These studies demonstrate that MCP-1 is an important mediator for monocyte recruitment in this model of glomerulonephritis. The reduction of M/M infiltration might affect this glomerular injury.

To test whether or not prostaglandins mediate extracellular matrix formation in immune-mediated glomerular disease, rats with anti-thymocyte antibody-induced glomerulonephritis were treated with prostaglandin E1 (PGE1) (250 micrograms/twice daily/s.c.). Glomerular expression of collagen types III and IV was assessed by Northern blotting, immunohistology and Western blotting. Proliferation of glomerular cells was evaluated by staining for the proliferating cell nuclear antigen (PCNA) and consecutive cell counting. At day five after induction of the disease, glomerular mRNA levels of collagen types III and IV were three- to fivefold higher compared with non-nephritic controls. Similarly glomerular deposition of these collagens was markedly increased when assessed by immunohistology. The treatment of nephritic rats with PGE1 reduced the increased glomerular mRNA levels as well as the protein concentration and the deposition of extracellular collagens. The number of PCNA positive cells which was significantly higher in nephritic rats when compared with control animals (24 hr, nephritis 2.53 +/- 0.33 and Control 0.26 +/- 0.06, P = 0.011; 5 days, nephritis 5.10 +/- 1.13 and Control 0.75 +/- 0.08, cells per glomerular cross section, P = 0.03) was reduced by PGE1 (24 hr, nephritis+PGE1 0.44 +/- 0.30, P = 0.0001; 5 days, nephritis +/- PGE1 1.91 +/- 1.84 cells per glomerular cross section, P = 0.001). Prostaglandin E1 also ameliorated the glomerular infiltration of monocytes at 24 hours (nephritis 4.36 +/- 2.82, nephritis + PGE1 2.20 +/- 1.82, cells per glomerular cross section) and five days (nephritis 1.51 +/- 0.58, nephritis+PGE1 1.12 +/- 0.61, cells per glomerular cross section). To further characterize possible mechanisms by which PGE1 reduces extracellular matrix deposition, the glomerular expression of transforming growth factor (TGF-beta), and interleukin 1 beta (IL-1 beta) was assessed by Northern blotting. Nephritic glomeruli showed increased mRNA levels of TGF-beta at day 5 and IL-1 beta at 24 hours when compared with control kidneys. Treatment of the animals with PGE1 inhibited the mRNA expression of TGF-beta and IL-1 beta. These data demonstrate that PGE1 reduces the glomerular expression of extracellular matrix proteins in anti-thymocyte antibody-induced glomerulonephritis, suggesting a beneficial role of prostaglandins in this proliferative glomerular immune injury. The effects of PGE1 might be mediated by inhibition of TGF-beta and IL-1 beta production.

To study whether prostaglandins (PG) can regulate the mRNA expression of monocyte-chemoattractant protein 1 (MCP-1) in glomerular immune injury, MCP-1 mRNA levels were evaluated in anti-thymocyte antibody (ATS) -induced glomerular injury by Northern blotting and reverse transcription-polymerase chain reaction. Immune injury was induced in vivo by the intravenous application of ATS to male Wistar rats and in vitro by the perfusion of isolated rat kidneys with ATS and rat serum. In vivo 3 h and 5 days after antibody application, glomerular mRNA expression of MCP-1 was markedly enhanced compared with controls. In the isolated perfused kidney, antibody and complement also induced an increase in MCP-1 expression at 10 min and 60 min after antibody perfusion. When the rats were treated with PGE (250 micrograms, twice daily), the increase in MCP-1 expression was reduced. This was associated with a reduction of intraglomerular recruitment of monocytes/macrophages. In the isolated perfused kidneys, PGE1 (1 mg/L) prevented the antibody- and rat serum-stimulated increase in glomerular MCP-1 mRNA expression. These data demonstrate that PGE1 reduces glomerular MCP-1 mRNA expression in glomerulonephritis and in the isolated perfused rat kidney after induction of immune injury with antibody and complement. The data suggest that prostaglandins might mediate MCP-1 effects in glomerular immune injuries.

Background: Converting enzyme inhibition (CEI) ameliorates progressive loss of function in non-immune-mediated renal diseases and experimental hypertension. Little, however, is known on the potential role of CEI in established experimental chronic glomerular immune injury. We therefore studied the effect of the CEI ramipril on renal function and morphology in a model of immune mediated glomerular injury., Methods: The immune complex glomerulonephritis was induced in uninephrectomized rats by intrarenal perfusion with the cationized antigen followed by an intravenous application of the antibody. This disease is characterized by the development of progressive albuminuria and a nephrotic syndrome (albuminuria: immune complex glomerulonephritis 342 +/- 58, control 76 +/- 18 mg/24h; P < 0.001). The CEI by ramipril, dissolved in the drinking water, was given 28 weeks after induction of the disease and treatment was continued for 12 weeks., Results: In these experiments ramipril significantly reduced albumin excretion (immune complex glomerulonephritis + CEI 109 +/- 16 mg/24h; P < 0.01) when compared with untreated nephritic rats. Ramipril, however, did not significantly change inulin clearances (immune complex glomerulonephritis 224 +/- 67, immune complex glomerulonephritis + CEI 278 +/- 48 microliters/min/100 g bw). Glomerular structural damage expressed as glomerular damage index was significantly greater in rats with immune complex glomerulonephritis when compared with controls (immune complex glomerulonephritis 0.91 +/- 0.13; control 0.60 +/- 0.08; P < 0.05), but was uneffected by the treatment with the CEI (immune complex) glomerulonephritis + CEI 1.02 +/- 0.26; control + CEI 0.63 +/- 0.11)., Conclusions: These data demonstrate that ramipril reduced albuminuria in a model of immune complex glomerulonephritis; however, it failed to alter GFR and glomerular damage index. The study suggests that ramipril ameliorates proteinuria independently of obvious glomerular histological changes. The reduction of proteinuria is, however, associated with a significant decrease in filtration fraction and therefore is at least partially haemodynamically mediated.

Antineutrophil cytoplasmic antibodies (ANCA) encompass a heterogeneous group of autoantibodies targeting antigens in neutrophils (PMN), monocytes, and endothelial cells. ANCA are routinely detected by the indirect immunofluorescence technique (IFT) and at least three different patterns of fluorescence can be distinguished which have been assigned the acronyms cANCA, pANCA and aANCA. cANCA is mostly induced by proteinase 3 (PR3) antibodies (PR3-ANCA), and pANCA by myeloperoxidase (MPO) antibodies (MPO-ANCA), while aANCA has unidentified subspecificity. Over the past decade, ANCA have been the subject of extensive investigation. They have proved to be of significant value both as diagnostic tools and for follow-up in several forms of systemic vasculitis (e.g. Wegener's granulomatosis, WG; microscopic polyarteritis, MPA; Churg-Strauss syndrome, CSS) which are now termed 'ANCA-associated vasculitides'. Furthermore, it is suspected that the presence of ANCA is an important factor in the pathogenesis of these disease groups. Data regarding the detection of ANCA and their diagnostic value and role in the pathogenesis of vasculitic disorders will be discussed in this review. Growing evidence points to a pathophysiological and diagnostic relevance of the distribution of the ANCA target antigens PR3 and MPO (presence in the circulation, on cell membranes, and in tissue extracellularly). An autoimmune process has been implicated in the pathogenesis of ANCA-associated vasculitis, but it is uncertain which mechanism underlies the induction of the ANCA-related immunoresponse. In this paper mechanisms such as antigenic cross-reactivity between human PMN proteins and extrinsic antigens by molecular mimicry, idiotypic immunoglobulin regulation, and T-cell reactivity to PR3 and MPO will be discussed.

The infiltration of monocytes-macrophages in the glomerulus is one of the hallmarks of glomerulonephritis and may play an important pathogenetic role. Monocyte chemoattractant protein-1 (MCP-1) and colony stimulating factor-1 (CSF-1) are monocyte-specific cytokines with chemoattractant and activating activities for monocytes. MCP-1 and CSF-1 can be generated by several cell types, including glomerular mesangial cells, and can be stimulated by cytokines and immune complexes. To study the expression of CSF-1 and MCP-1 in a model of proliferative glomerulonephritis we used Northern blot analysis and immuno-histochemistry. The glomerular lesion was induced in rats by the i.v. injection of a heterologous anti-thymocyte antiserum (ATS), directed against an antigen which is localized on glomerular mesangial cells. Northern blot analysis revealed comparable amounts of CSF-1 in glomeruli isolated from control untreated rats, and from rats after 30 minutes to three weeks of injection of ATS antibody. In control glomeruli no mRNA levels for MCP-1 were detectable, but increased markedly 30 minutes after the induction of the nephritis, were then reduced at 24 hours and increased again at 5 and 21 days after induction of the disease. The increase in mRNA levels for MCP-1 30 minutes or 24 hours after ATS injection was markedly attenuated if rats were complement depleted by cobra venom injection. These time points following antibody injection were associated with mesangial immune complex formation (30 min), mesangiolysis (24 hr) and proliferative glomerulonephritis (5 and 21 days). By immunohistology the presence of MCP-1 was demonstrated in glomeruli with a predominant mesangial distribution. The mesangial immunofluorescence for MCP-1 followed a pattern similar to that of the mRNA for MCP-1 after induction of the disease process, that is, it increased after 30 minutes, decreased after 24 hours and was increased again at three weeks. Within 30 minutes of the antibody injection an increased infiltration of monocytes-macrophages was observed in the glomeruli, which was maintained up to three weeks of induction of the glomerulonephritis. When the rats were decomplemented with cobra venom factor prior to the i.v. injection of ATS, the expression of MCP-1 in glomeruli remained low and the influx of monocytes/macrophages did not appear. We conclude that MCP-1 is increased early on in glomeruli of rats with immune-mediated mesangial proliferative glomerulonephritis. This increase is mediated by complement activation secondary to the in situ immune complex formation at the glomerular mesangium.(ABSTRACT TRUNCATED AT 400 WORDS)

A patient developed relapsing inflammatory demyelinating polyradiculoneuropathy associated with nephrotic syndrome. Renal biopsy showed focal-segmental glomerulosclerosis. The review of the literature disclosed that glomerulonephritis with and without nephrotic syndrome seems to be not uncommon in inflammatory demyelinating polyradiculoneuropathy, such as Guillain-Barré syndrome. membranous glomerulonephritis is the most frequent histologic diagnosis while minimal change nephropathy, 'acute glomerulonephritis' and postinfectious type glomerulonephritis are not often present. This is the first case of inflammatory demyelinating polyradiculoneuropathy associated with nephrotic syndrome due to focal-segmental glomerulosclerosis. Larger prospective studies are necessary and may contribute to the understanding of the pathogenesis of both, glomerulonephritis and inflammatory demyelinating polyradiculoneuropathy.

A patient, born in 1968, was found at the age of 9 years to have Alport's syndrome. In his 20th year, when in terminal renal failure, his father's kidney was transplanted into him. 14 months later there was a sudden worsening of his renal function after a varicella infection; for the first time antibodies against the glomerular basal membrane (GBM) were detected. Despite an increase in prednisolone dosage and 6 plasmaphereses chronic haemodialysis again became necessary. Renal biopsy revealed necrotizing intra- and extracapillary glomerulonephritis. Simultaneously there was a raised anti-NC-1-antibody titre (1:80) in the serum. After removal of the transplant the titre fell to normal. The NC-1 antigen, a component of the GBM in healthy persons, may be absent in Alport's syndrome. An analysis of the few cases of anti-GBM glomerulonephritis in renal transplants of patients with Alport's syndrome may make it possible to recognize factors which precipitate or favour this form of glomerulonephritis.

Rats were treated with the platelet activating factor receptor antagonist WEB 2170 (15 mg/kg/day) in three different protocols to evaluate a possible role of platelet activating factor in an experimental proliferative model of glomerular disease. The glomerular immune injury was initiated by the i.v. administration of a rabbit anti-rat thymocyte antiserum. Anti-rat thymocyte antiserum induces a proliferative glomerulonephritis with reduction of glomerular filtration rate (614 +/- 94) compared with controls (1,120 +/- 192 microL/min/100 g body wt) when studied at day 7. Treatment of rats with WEB 2170 over 8 days (starting at day -1; protocol 1) ameliorated the loss in glomerular filtration rate (936 +/- 82 microL/min/100 g body wt) in nephritic rats at day 7; however, it had no effect on controls (1,142 +/- 104 microL/min/100 g body wt). Interventional treatment with WEB 2170 (starting at day 4 after anti-rat thymocyte antiserum; protocol 2) also improved glomerular function when glomerular filtration rate was already reduced (410 +/- 41 microL/min/100 g body wt) at day 4. The platelet activating factor receptor antagonist given at day 7 after induction of disease (protocol 3) did not improve impaired glomerular filtration rate. Preinterventional and interventional treatment with WEB 2170 reduced the infiltration of polymorphonuclear granulocytes in glomeruli. Interventional treatment with WEB 2170 also reduced glomerular morphologic damage in nephritic glomeruli. The data demonstrate a beneficial effect of the platelet activating factor receptor antagonist in this animal model of proliferative glomerulonephritis which suggests that platelet activating factor might play an important role in the mediation of this disease.

We studied the formation of cyclo-oxygenase products in a rat model of mesangial cell injury, in order to determine a possible role of prostaglandin E2 (PGE2), prostaglandin I2 (determined as 6-keto-PGF1 alpha and thromboxane A2 (TxA2) in immune-mediated glomerular disease. Selective immune-mediated mesangial cell injury was induced by i.v. administration of a rabbit anti-rat thymocyte antiserum (ATS). Intravenous ATS leads to immune deposits in the mesangium followed by mesangiolysis and the infiltration of polymorphonuclear granulocytes and monocytes. Glomerular TxB2 formation two hours (292 +/- 27 pg/mg/min) and 48 hours (396 +/- 69 pg/mg/min) following antibody was significantly (P less than 0.05) higher compared to animals receiving non-antibody rabbit IgG (TxB2: 2 hr 143 +/- 13; 48 hr 171 +/- 32 pg/mg/min). Treatment with cobra venom factor (CVF) and the reduction of glomerular monocyte infiltration inhibited the increase of glomerular TxB2 formation significantly. Depletion of granulocytes with a rabbit anti-rat granulocyte serum had no effect on glomerular prostanoid formation following ATS. Glomerular PGE2 and 6-keto PGF1 alpha production was not altered following ATS. Inulin clearance in rats with immune-mediated mesangial cell injury was significantly (P less than 0.001) lower at two hours (456 +/- 24 microliters/min/100 g body wt) and 48 hours (433 +/- 54 microliters/min/100 g body wt) compared to their corresponding control animals which were treated with non-antibody IgG (2 hr: 914 +/- 51; 48 hr: 694 +/- 79 microliters/min/100 g body wt).(ABSTRACT TRUNCATED AT 250 WORDS)

Recurring upper respiratory tract infections in a previously healthy 4 years old boy led to an acute nephritic syndrome requiring haemodialysis. Renal biopsy showed poststreptococcal like immune complex glomerulonephritis with subepithelial humps, C3 deposition and crescent formation. Renal function improved after methyl-prednisolone pulse therapy. Two relapses occurred in the following six months which responded to immunosuppressive therapy. 21 months following the first presentation the boy has normal glomerular filtration rate but persistent glomerular proteinuria and haematuria. Detailed complement analyses revealed a persistent activation of the alternate pathway.

The results of electron microscopic examination of renal biopsies from 3 patients with rheumatoid arthritis treated with penicillamine are presented. All 3 patients developed a nephrotic syndrome upon discontinuation of penicillamine therapy. When viewed with the electron microscope, segmental forms of perimembranous glomerulonephritis (Stages I-II of Ehrenreich and Churg) and glomerular renal amyloidosis Grade I-III were observed. In all three cases the nephrotic syndrome was considered to be due to the simultaneous occurrence of the two disease processes. In 2 cases perimembranous glomerulonephritis with immuno-complex-deposits was assumed to be the dominant factor in the causation of the disease, in the other case amyloidosis was the principle abnormality.

The development of an age-dependent glomerulosclerosis and proteinuria was investigated in two strains of rats in a model of moderate hypertension comparing rats of the Milan Hypertensive Strain (MHS) with rats of the Milan Normotensive Strain (MNS). Serum creatinine, urinary protein excretion, renal morphology (light- and electronmicroscopy) and morphometry of the media thickness of the intrarenal arteries and of the thickness of the glomerular basement membrane were studied in 2- to 16-month-old MHS and MNS rats. Serum creatinine did not differ between MNS and MHS rats in any age group. MNS rats developed a significant proteinuria which coincided with a glomerulosclerosis in about 22% of the glomeruli at 13 to 16 months. In contrast, urinary protein excretion in MHS rats remained stable during the entire observation period; glomerulosclerosis occurred only in 3% of the glomeruli at 13 to 16 months. As a consequence of hypertension media thickness of intrarenal arteries of MHS rats significantly exceeded that of MNS rats, in the interlobular arteries already at 2 months and in the arcuate arteries at 13 to 16 months. In contrast, thickness of the glomerular basement membrane of MHS rats never exceeded that of MNS rats. From these data we conclude, that glomeruli of MHS rats may be protected against the development of an age-dependent glomerulosclerosis and proteinuria. Further support for this conclusion may also be derived from recent experiments showing that the tubuloglomerular feedback sensitivity is significantly higher in MHS than in MNS rats (41).

In a pilot study 23 children with nephrotic syndrome were treated with cyclosporin A (Cs) for 6-45 months. 8 children suffered from steroid dependent minimal change nephrotic syndrome (MCNS) and had experienced at least one course with cytotoxic drugs, but had relapsed thereafter. 2 children had diabetes mellitus type I with nephrotic syndrome and 13 children had steroid resistant focal segmental glomerulosclerosis (FSGS). Cs was started with 100 mg/m2/day in two doses and increased stepwise to obtain a Cs whole blood trough level of 200-400 ng/ml. In steroid dependent MCNS treatment with Cs reduced relapse rate significantly, and prednisone therapy could be stopped completely. After discontinuation of Cs, relapses reoccurred as frequently as before. Renal function remained unimpaired despite repeated Cs treatment courses up to 38 months. In cases of nephrotic syndrome with diabetes type I Cs treatment led to complete remission without changing the insulin requirement. However, after discontinuation of Cs relapses reoccurred. In steroid resistant FSGS 6 children benefited from Cs treatment: 4 went into complete remission, 2 into partial remission. The 2 children with complete remission relapsed but remained Cs responsive. The remaining 7 children with FSGS did not respond to Cs but continued the course of their disease, with two patients rapidly progressing to terminal renal failure. Side-effects of Cs treatment were mild. It is concluded that Cs is an effective agent in steroid dependent MCNS and can be used as an alternative drug in specific cases like steroid toxicity or diabetes mellitus. In steroid resistant FSGS a trial with Cs seems to be warranted since some cases do respond favorably. To avoid nephrotoxicity treatment with Cs should always be monitored closely by determination of blood levels and renal function.

This paper sets out the arguments for drug treatment of chronic glomerulonephritides (GN). Although the pathogenesis and mechanism of progression of chronic GN remained to be clarified, on the basis of controlled studies performed to date, there is a strong case to be made for an aggressive treatment approach to this disease spectrum. For instance, in patients with idiopathic membranous glomerulonephritis a six months treatment with chlorambucil (0.2 mg/KG/day) or prednisone (0.6 mg/KG/day) each given once a day over a period of three months has recently been shown to improve the outcome of the renal functional parameters after three years follow up. In another controlled trial a daily dose of 225 mg dipyridamole and 975 mg aspirin given over 12 months in patients with membrano-proliferative GN type I has been reported to normalize the increased platelet consumption rate and to stabilize the glomerular filtration rate. A third trial has demonstrated that the combined use of cyclophosphamide (100 mg/day) and prednisone (30 mg/day) over several months was superior to the use of prednisone alone (40 mg/day) in improving the long-term prognosis of diffuse-proliferative lupus nephritis (type IV, WHO). In some entities, however, as in IgA-nephritis there is still no evidence for a specific treatment improving the course of the chronic glomerular disease. Other therapeutic problems have to be solved: thus, in patients with minimal change nephropathy with a steroid dependent nephrotic syndrome the benefit of cyclophosphamide (given over three months) or of cyclosporin A is still being investigated. Furthermore, there is some evidence that progression of chronic GN, particularly that of glomerular sclerosing, can be prevented by a low protein diet. The role of eicosanoides and their inhibitors in this context has not yet been fully investigated. The different drug trials and new therapeutic concepts indicate a rapid development of chronic GN treatment. Therefore, a failure to treat actively is difficult to understand.

Clinical and experimental data indicate that glomerular function and morphology may be influenced by plasma lipids. In familial lecithin-cholesterol-acyltransferase (LCAT) deficiency and in Fabry's disease, lipids accumulate in glomeruli and are assumed to induce sclerosis. The present study was undertaken to examine if dietary lipids could exert effects on the glomeruli of normal, unilaterally nephrectomized rats, and of rats with two-kidney, one clip (2-K,1C) hypertension. In rats with two kidneys on a diet rich in fat and cholesterol, cholesterol concentrations in very low density lipoproteins increased. In these rats the number of glomeruli with sclerotic foci was significantly higher than in rats on a low fat, cholesterol free diet. After 6 months on the diet the percentage of glomeruli with sclerosis (SC) was 13.2 +/- 4.1 (N = 9) in rats with a cholesterol diet and 1.8 +/- 0.6 (N = 11) in control rats (p less than 0.05). The fat and cholesterol diet exacerbated glomerular lesions in the remnant kidney model of uninephrectomized rats. The sclerosis in rats with only one kidney was 38.2 +/- 9.5 (N = 6) on a cholesterol diet compared with 8.7 +/- 3.0 (N = 6) in control rats after 6 months (p less than 0.05). After 3 to 4 months on a fat rich diet cholesterylester was increased in isolated glomeruli. The composition of the dietary lipids influenced the development of glomerular lesions. A linseed oil diet that is rich in unsaturated fatty acids, especially linolenic acid, did not cause major plasma lipid abnormalities and was accompanied by a low sclerosis (1.2 +/- 0.3; N = 9) for rats with two kidneys. In rats with chronic 2-K, 1C hypertension the percentage of glomeruli with partially sclerosed tufts in the unclipped kidney was significantly higher on a fat and cholesterol diet (F) than on a control diet (N) (SC: diet F 31.0 +/- 4.0, N = 13; diet N 12.2 +/- 2.6, N = 12; P less than 0.05). In the clipped kidney, protected against the arterial hypertension, only an increased number of glomeruli with mesangial expansion was noted in rats with the cholesterol diet. Glomerular hemodynamic factors seem to play an important pathogenetic role in the induction of glomerular sclerosis by a lipid rich diet. The fact that dietary lipids can aggravate glomerular lesions in states of arterial hypertension and nephron loss may have implications for the progression of renal disease in humans.

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Objective: The infiltration of inflammatory cells into renal tissue, mainly T cells and monocytes, is a typical feature of various renal diseases affecting the endothelium such as glomerulonephritis, thrombotic angiopathies, allogaft rejection and vasculitis. Chemokines are the chemotactic cytokines considered to be the main regulators of leukocyte trafficking under inflammatory conditions. The aim of our study was to analyze the expression and function of the chemokine IP-10/CXCL10 (acting via CXCR3 on activated T cells) in a rat model of renal microvascular endothelial injury. Methods: Renal microvascular endothelial injury was induced in rats by selective renal artery perfusion with anti-endothelial-antibody (Kidney Int 97, Johnson et al). Chemokine expression (Real time-PCR and in situ hybridization), T cell and monocyte infiltration (immunohistochemistry and FACS analysis) and serum creatinine/urea levels were assessed 24 h and 4 days after disease induction. To analyze the functional role of IP-10/CXCL10, rats were treated with a characterized neutralizing anti IP-10 antibody following induction of the endothelial injury. Results: Induction of microvascular endothelial injury increased renal IP-10/CXCL10 expression at 24 h (117-fold) and 4 days (5-fold). In situ hybridization revealed that IP-10/CXCL10 RNA is selectively expressed in the tubulointerstitial area (mainly by endothelial cells), co-localizing with infiltrating T cells. Treatment with a neutralizing anti IP-10/CXCL10 antibody significantly reduced the number of infiltrating tubulointerstitial T cells, serum creatinine and urea level. No significant glomerular IP-10/CXCL10 expression and T cell infiltration was detectable. Monocyte recruitment was not affected by anti IP-10/CXCL10 treatment, demonstrating a predominant role of this chemokine in tubulointerstitial T cell recruitment. Conclusions: Our findings demonstrate that microvascular renal injury leads to the tubulointerstitial expression of IP-10/CXCL10. The data provide strong evidence that a IP-10/CXCL10 mediated T cell recruitment is of functional importance in this model of microvascular injury. [ABSTRACT FROM AUTHOR]