Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0033687 (proteinuria)
 24,015 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The pathogenesis of chronic membranous glomerulonephritis induced in rats by passive immunization with heterologous antibodies to rat renal tubular epithelial (RTE) antigens was investigated. This model is designated as "passive Heymann nephritis" (PHN) in order to contrast it with classical Heymann nephritis induced by active immunization with homologous RTE in adjuvant. A single i.v. injection of heterologous (rabbit) antibody to RTE evoked chronic proteinuria after a latent period of one to three days. The onset of proteinuria was accompanied by the granular deposition of rabbit IgG and rat beta1C globulin along the glomerular capillary wall. Renal isografts developed PHN only when transplanted within the first three days following injection of the heterologous anti-RTE antibodies. The data suggest that the heterologous antibodies form immune complexes with RTE antigens preexisting in the circulation, and these complexes subsequently deposit in the glomerular capillary walls. Chronic proteinuria is then perpetuated by a host reaction to the foreign protein in the deposits (i.e., rabbit IgG), in a fashion analogous to that seen in the autologus phase of nephrotoxic serum nephritis. These studies indicate that continued glomerular deposition of preformed circulating immune complexes may not always be a requisite for the perpetuation of glomerular injury in immune complex disease.
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PMID:Chronic nephritis induced by antibodies reacting with glomerular-bound immune complexes. 32 57

The role of circulating immune complex deposition versus in situ complex formation in membranous nephropathy is controversial. Passive Heymann nephritis in rats resembles membranous nephropathy in man and was induced by injection of sheep antibody to rat proximal tubular epithelial cell brush border antigen (anti-Fx1A). Minutes after injection of 1 ml. of anti-Fx1A, subepithelial immune deposits were seen by immunofluorescence and electron microscopy, and proteinuria appeared within 5 days. The effects of alterations in the dose of administered antibody, corticosteroid therapy, and vasoactive amine blockade on the development of subepithelial deposits and consequent proteinura were studied. Variation of the dose of anti-Fx1A from 0.25 ml. to 1 ml. resulted in a progressive increase in the size and number of glomerular capillary wall deposits, but no alterations in their distribution. Only those rats which received 1 ml. became proteinuric within 5 days. Corticosteroid therapy and vasoactive amine blockade, begun 24 hours prior to the induction of passive Heymann nephritis and continued until termination of the study 5 days later, had no effect on the amount or site of immune complex formation, nor on the extent of proteinuria as compared to untreated controls. In contrast, in rats with unilateral proteinuria produced by the selective perfusion of one kidney with aminonucleoside of puromycin 7 days prior to the induction of passive Heymann nephritis, there was a marked reduction of subepithelial deposits in the perfused kidney as compared to the nonperfused contralateral kidney. In this model of membranous nephropathy, systemic factors play little role in the development of subepithelial deposits, whereas local factors are critical. These findings are consistent with the hypothesis that subepithelial immune deposits form locally.
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PMID:Determinants of glomerular localization of subepithelial immune deposits: effects of altered antigen to antibody ratio, steroids, vasoactive amine antagonists, and aminonucleoside of puromycin on passive Heymann nephritis in rats. 37 41

1. To study the long term course of passive Heymann nephritis (PHN), 42 adult male Wistar rats were injected with rabbit anti-FX1A serum (PHN group) and 42 rats received normal rabbit serum (control group). Two animals from each group were sacrificed 2 weeks after the inoculation and 10 animals each from the control and PHN groups were sacrificed 4, 13, 25 and 53 weeks later. 2. The PHN group exhibited a significant elevation in 20-h proteinuria which lasted from the first week (control group, 9.19 +/- 0.87; PHN group, 25.3 +/- 2.66) to the 25th week (control group, 22.6 +/- 2.15; PHN group, 66.7 +/- 10.4) except for week 17. From week 29 to week 53 there was no statistical difference between the 2 groups. 3. Light microscopy showed no difference between the kidneys of PHN and control rats. Immunofluorescence microscopy in PHN rats showed granular deposition of autologous and heterologous IgG on the glomerular basement membrane (GBM), whose intensity and pattern did not change during 53 weeks of observation. 4. When examined by electron microscopy the glomeruli of PHN rats showed: a) electron-dense deposits which were initially subepithelial and homogeneous and later intramembranous, granular and often surrounded by an electron-transparent halo; b) focal thickening of the GBM at the sites of intramembranous deposits; c) effacement of podocytes located close to the deposits; d) "penetration" of the podocytes into the GBM associated with the deposits; e) presence of osmiophilic granules in the cytoplasm of the podocytes located inside the GBM similar to the granules of the deposits next to them. The association of the penetration of the podocytes into the GBM with the deposits and the presence of the osmiophilic granules inside the foot process have not been described previously in PHN.
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PMID:The long-term evolution of immune deposits in passive Heymann nephritis. 133 11

FK506 is a recently-developed immunosuppressive drug. The aim of the present work was to investigate the effects of FK506 in experimental autoimmune glomerulonephritis (active Heymann nephritis) in rats. Active Heymann nephritis was induced in female Lewis rats by two immunizations with the homologous brush border vesicles (BBVs) at day 0 and day 28 (groups I, II, V, and VI). Rats of groups III and IV received the third immunization at day 56. In rats of groups I and III, FK506 was injected (1 mg/kg/day IM) from day 0 for 14 days. In rats of groups II and IV, significant proteinuria was observed (group II, 112.8 mg/16 hours; group IV, 55.4 mg/16 hours) at the time the rats were killed (day 84). Coarse subepithelial immune deposits (IDs) were found in these rats. In contrast, urinary protein excretion remained within normal range (less than 3.0 mg/16 hours) in groups I and III rats, and tiny subepithelial IDs were only occasionally seen. Circulating anti-BBV antibody levels were markedly lower in group I and III rats than in those of groups II and IV during the period between day 14 and day 56. To investigate the effects of FK506 on the proteinuric rats, FK506 (1 mg/kg/day, IM) was administered every day for 2 weeks beginning on day 56 (group V).(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Effects of a new immunosuppressive agent, FK506, in rats with active Heymann nephritis. 137 Dec 98

Alterations of the anionic charge and/or sites of the glomerular basement membrane (GBM) in the heterologous phase of passive Heymann nephritis (PHN) were studied. Rats with PHN induced by a single injection of anti-Fx1A IgG were examined at days 1, 2, 3 and 4. The left kidney was perfused with ruthenium red (RR) solution as a cationic probe. The RR particles (= anionic sites) in the GBM were counted and expressed as the number of RR particles per unit length of GBM. For quantitative determination of the total anionic charge of the GBM, the GBM-bound ruthenium (= anionic charge) was measured with an atomic absorption spectrophotometer (AAS). Abnormal proteinuria corresponding to a decrease in anionic charge was detected at days 3 and 4. The anionic sites in the lamina rara externa (LRE) adjacent to immune complex (IC) deposits were found to have diminished earlier from day 1 onwards. This diminution was largely confined to areas adjacent to the IC deposits and was significantly correlated with the amount of urinary albumin excretion. Proteinuria in the heterologous phase of PHN would thus appear to be causally related to a decrease in the number of anionic sites in the LRE adjacent to IC deposits.
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PMID:Alterations of anionic charge and/or sites of the glomerular basement membrane in the heterologous phase of passive Heymann nephritis. 137 13

Chronic progressive membranous nephropathy (MN) in humans is characterized by thickening of the glomerular basement membrane (GBM) with formation of spikes which contain laminin and other extracellular matrix (ECM) proteins. We have utilized two models of MN in the rat (active and passive Heymann nephritis, AICN, PHN) to define the sequential changes in composition of GBM as they relate to changes in glomerular gene expression for ECM components, altered permeability and morphological changes. Renal biopsies obtained during the course of AICN and PHN were immunostained for various ECM proteins and total glomerular RNA was hybridized with cDNA probes specific for laminin B2-chain, s-laminin, and types I and IV collagen. In addition, the ability of anti-glomerular epithelial cell (GEC) antibody and complement on rat GEC in culture to induce laminin release or laminin and s-laminin mRNA expression was determined. The results demonstrate that at weeks 12, 16, and 20 of AICN, immunostaining for laminin, s-laminin, fibronectin, entactin, and heparan sulfate proteoglycan increased in the GBM in a spike-like pattern. Concomitantly, glomerular mRNA levels of laminin B2-chain and of s-laminin increased. Type IV collagen protein and gene expression remained unchanged or decreased. No glomerular immunostaining for type I collagen occurred during AICN despite increased expression of mRNA for this collagen type. In contrast to AICN, in PHN no pronounced changes of the glomerular ECM occurred, except for transient expression of type I collagen mRNA in whole glomerular RNA and type I collagen protein the GEC cytoplasm. Stimulation of GEC in culture with anti-GEC antibody and complement also failed to induce transcription of laminin or s-laminin mRNA or the release of laminin protein. These findings suggest that the polyantigenic expansion of GBM which occurs in chronic experimental MN may be stimulated by factors different from the C5b-9 mediated processes that cause the initial proteinuria.
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PMID:Altered glomerular extracellular matrix synthesis in experimental membranous nephropathy. 138 96

We showed previously that proteinuria caused delayed chylomicron (CM) clearance in the rat and postulated the existence of a primary defect in CM hydrolysis. It was possible that reduced CM clearance resulted from increased lipogenesis causing saturation of catabolic sites and not from a primary defect in CM catabolism. To clarify this point we measured kinetically the absolute rate of triglyceride (TG) uptake from CM in rats with Heymann nephritis (HN) and normal Sprague-Dawley rats (SD) and determined TG uptake in individual tissues using [3H]TG- and [14C]cholesterol-labeled CM. Hepatic [14C]cholesterol uptake was reduced in HN (69.3 +/- 6 vs. 7.2 +/- 2% of dose, P less than 0.001). TG uptake was reduced in HN measured kinetically (1.01 +/- 0.09 vs. 0.213 +/- 0.028 mg TG.min-1.100 g body wt-1, P less than 0.001) and reduced in all tissues (heart, skeletal muscle, fat, and liver). CM are catabolized on the vascular endothelium to atherogenic, cholesterol-rich remnant (CM remnant) particles, which are then rapidly taken up by the liver. We measured hepatic CM remnant uptake in SD and in HN using [14C]cholesterol-labeled CM remnant. CM remnant uptake was significantly reduced in HN (58 +/- 1.2 vs. 20 +/- 0.86% uptake, P less than 0.01). CM remnants were increased significantly in plasma of HN. Thus the nephrotic syndrome causes a primary defect in the uptake of TG from CM that is expressed in all tissues and a separate defect in hepatic CM remnant uptake. Although CM remnant generation is impaired because of defective CM hydrolysis, the defect in hepatic CM remnant uptake is so severe that these particles accumulate in blood, posing a potential risk for atherogenesis.
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PMID:Both peripheral chylomicron catabolism and hepatic uptake of remnants are defective in nephrosis. 151 Jan 25

The nephrotic syndrome results from altered glomerular permselectivity, causing urinary protein loss, reduced albumin concentration, oncotic pressure (pi), and hyperlipidemia. Hepatic lipid and apolipoprotein synthesis increases and lipoprotein catabolism decreases. Decreased lipoprotein catabolism follows the onset of proteinuria but is not associated with hereditary analbuminemia [Nagase analbuminemic rat (NAR)] if proteinuria is absent. We measured plasma apolipoproteins (apo) AI, B, and E levels, their mRNA concentrations in liver, and the transcription rate of each mRNA in rats with Heymann nephritis (HN) or NAR to determine which alterations occurred in NAR alone without proteinuria. Plasma apo AI, B, and E were increased in both HN and NAR. Cholesterol and apo AI were inversely proportional to pi and independent of urinary protein loss or the presence of albumin in plasma. In contrast, triglycerides (TGs) were significantly greater in HN and were increased out of proportion to apo B. The concentration of apo AI mRNA increased in liver of both HN and NAR as did apo AI transcription. Apo E mRNA increased in neither HN nor NAR, whereas apo B mRNA increased only in HN. Transcription of neither apo B nor E increased. Plasma apo AI levels are likely to be regulated transcriptionally at the level of protein synthesis, whereas plasma apo B and E levels are regulated either posttranscriptionally, at the level of protein catabolism, or at both sites. Lipoproteins rich in TG and poor in apo B appear after the development of proteinuria but not as a consequence of analbuminemia alone. The accumulation of TG-rich apo B containing lipoproteins in rats with HN may result from impaired lipolysis occurring as a consequence of proteinuria.
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PMID:Apolipoprotein gene expression in analbuminemic rats and in rats with Heymann nephritis. 159 Apr 20

We examined the effect of a selenium-deficient diet on two experimental models of glomerular disease, the puromycin aminonucleoside (PAN)-induced nephrotic syndrome, a model of minimal change disease, and passive Heymann nephritis, a complement-dependent and neutrophil-independent model that resembles membranous nephropathy. The specific activity of selenium-dependent glutathione peroxidase was markedly reduced in the liver, the kidney cortex, and in glomeruli in weanling male Sprague-Dawley rats placed on a selenium-deficient diet for 6 wk compared with rats fed a selenium-replete diet, with no significant differences in the specific activities of superoxide dismutase or catalase. PAN-injected selenium-deficient rats had a marked and significantly greater proteinuria throughout the course of the experiment compared with PAN-injected selenium-replete rats with no significant histological differences. In the passive Heymann nephritis model induced by injecting anti-Fx1A immunoglobulin G, rats fed a selenium-deficient diet had significantly higher urinary protein (day 5: 91 +/- 16 mg/24 h, n = 10) compared with rats fed a selenium-replete diet (52 +/- 5 mg/24 h, n = 11) with no differences in the amount of antibody deposited in the kidney. The most likely explanation for the effect of a selenium-deficient diet is that selenium deficiency resulted in a marked reduction of glutathione peroxidase, thus indicating an important role of glutathione peroxidase in these models of glomerular injury.
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PMID:Effect of selenium-deficient diet in experimental glomerular disease. 163 44

Heymann nephritis in the rat is a proteinuric condition caused by glomerular lesions similar to those found in human membranous nephritis. In the present study the effect of two different receptor antagonists of platelet-activating factor (PAF) on the course of passive Heymann nephritis was assessed. It was found that rats treated with either antagonist showed the same degree of proteinuria and the same glomerular immunopathological features as untreated rats. Furthermore, at sacrifice, 7 days after the initiation of the disease, the concentration of circulating PAF in treated as well as untreated rats was normal. These results indicate that PAF is not crucial in the pathogenesis of Heymann nephritis.
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PMID:Receptor antagonists of platelet-activating factor do not influence the development of passive Heymann nephritis. 166 16


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