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J H Berden

Publications and source records attributed to J H Berden.

At least 19 recordsLinked to original sources
PubMed1996

N-Acetylated domains in heparan sulfates revealed by a monoclonal antibody against the Escherichia coli K5 capsular polysaccharide. Distribution of the cognate epitope in normal human kidney and transplant kidney with chronic vascular rejection.

The Escherichia coli K5 capsular polysaccharide has the same (GlcUA-->GlcNAc)n structure as the nonsulfated heparan sulfate/heparin precursor polysaccharide. A monoclonal antibody (mAb 865) against the K5 polysaccharide has been described (Peters, H., Jürs, M., Jann, B., Jann, K., Timmis, K. N., and Bitter-Sauermann, D. (1985) Infect. Immun. 50, 459-466). In this report, we demonstrate the binding of anti-K5 mAb 865 to N-acetylated sequences in heparan sulfates and heparan sulfate proteoglycans but not to heparin. This is shown by direct binding and fluid phase inhibition of mAb 865 in an enzyme-linked immunosorbent assay. In this system we found that the binding of the mAb decreased with increasing sulfate content of the polysaccharide. By testing chemically modified K5 and heparin polysaccharides, we found that each of the modifications that occur during heparan sulfate (HS) synthesis (N-sulfation, C-5 epimerization, and O-sulfation) prevents recognition by mAb 865. Samples of heparan sulfate from human aorta (HS-II) were selectively degraded so as to allow the separate isolation of N-sulfated and N-acetylated block structures. N-Sulfated oligosaccharides (obtained after N-deacetylation by hydrazinolysis followed by nitrous acid deamination at pH 3.9) were not recognized by mAb 865, in contrast to N-acetylated oligosaccharides (obtained after nitrous acid deamination at pH 1.5), although the reactivity was lower than for intact HS-II. Analysis of the latter's pH 1.5 deamination products by gel filtration indicated that a minimal size of 18 saccharide units was necessary for antibody binding. These results lead us to propose bivalent antibody-heparan sulfate interaction, in which both F(ab) domains of the mAb interact with their epitopes, both of which are present in a single large (>/=18 saccharide units) N-acetylated domain and additionally with single epitopes present in two N-acetylated sequences (each <18 saccharide units) bridged by a short N-sulfated domain. Immunohistochemistry with mAb 865 on cryostat sections of normal human kidney tissue, revealed its binding to most but not all renal basement membranes. However, all renal basement membranes contain heparan sulfate, as shown by a mAb against heparitinase-digested heparan sulfate stubs (mAb 3G10). This finding indicates that not all heparan sulfate chains present in basement membranes express the mAb 865 epitopes. Besides the normal distribution, mAb 865 staining was found in fibrotic and sclerotic lesions in vessels, interstitium, and mesangium in transplant kidneys with chronic vascular rejection. Occasionally, a decrease of staining was observed within tubulo-interstitium and glomeruli. These findings show that N-acetylated sequences in heparan sulfates can be demonstrated by anti-K5 mAb 865 in normal and diseased kidneys.

Acetylation↗
PubMed1996

Heparan sulfate staining of the glomerular basement membrane in relation to circulating anti-DNA and anti-heparan sulfate reactivity: a longitudinal study in NZB/W F1 mice.

Reactivity of serum antibodies with heparan sulfate (HS) has been associated with human and murine lupus nephritis, although the aetiological significance of this association is not clear. Recent work from our laboratories showed that binding of these antibodies to HS could be mediated by histone containing immune complexes. In human lupus nephritis we found a strong decrease in HS staining in the glomerular basement membrane (GBM). The aim of this study was to elucidate the correlation in experimental systemic lupus erythematosus (SLE) between albuminuria, staining of HS in the GBM and anti-DNA and anti-HS reactivity in plasma. We therefore studied NZB/W F1 mice during different stages of glomerular disease and compared them with age matched control NZB/W F1 mice without albuminuria. Anti-DNA and anti-HS reactivity were measured in longitudinally collected plasma samples and correlated with the onset of albuminuria, staining of HS in the glomerular basement membrane and deposition of immunoglobulins (Ig). HS staining was significantly decreased in the glomerular capillary loops of mice with prolonged proteinuria in comparison with age matched control mice (P = 0.0013). This decreased HS staining was correlated with increased Ig deposition in the capillary loops (tau = -0.42, P < 0.001), albuminuria (tau = -0.508, P < 0.001) and a decreased in anti-DNA levels measured in plasma (tau = 0.758, P < 0.005). Altered anti-HS reactivity in plasma did correlate with increased Ig deposition in the kidney (tau = 0.33, P < 0.05) but was not correlated with decreased staining of HS in the kidney. In conclusion, our study demonstrates that disappearance of staining of HS in the glomerular capillary loops is associated with albuminuria, increased Ig deposition in the glomerulus and decreased anti-DNA reactivity in plasma. Our findings are compatible with a model in which interaction ('masking') of HS with immune complexes consisting of anti-DNA antibodies and nucleosomes takes place.

Animals↗
PubMed1996

Effects of high glucose on the production of heparan sulfate proteoglycan by mesangial and epithelial cells.

Changes in heparan sulfate metabolism may be important in the pathogenesis of diabetic nephropathy. Recent studies performed on renal biopsies from patients with diabetic nephropathy revealed a decrease in heparan sulfate glycosaminoglycan staining in the glomerular basement membrane without changes in staining for heparan sulfate proteoglycan-core protein. To understand this phenomenon at the cellular level, we investigated the effect of high glucose conditions on the synthesis of heparan sulfate proteoglycan by glomerular cells in vitro. Human adult mesangial and glomerular visceral epithelial cells were cultured under normal (5 mM) and high glucose (25 mM) conditions. Immunofluorescence performed on cells cultured in 25 mM glucose confirmed and extended the in vivo histological observations. Using metabolic labeling we observed an altered proteoglycan production under high glucose conditions, with predominantly a decrease in heparan sulfate compared to dermatan sulfate or chondroitin sulfate proteoglycan. N-sulfation analysis of heparan sulfate proteoglycan produced under high glucose conditions revealed less di- and tetrasaccharides compared to larger oligosaccharides, indicating an altered sulfation pattern. Furthermore, with quantification of glomerular basement membrane heparan sulfate by ELISA, a significant decrease was observed when mesangial and visceral epithelial cells were cultured in high glucose conditions. We conclude that high glucose concentration induces a significant alteration of heparan sulfate production by mesangial cells and visceral epithelial cells. Changes in sulfation and changes in absolute quantities are both observed and may explain the earlier in vivo observations. These changes may be of importance for the altered integrity of the glomerular charge-dependent filtration barrier and growth-factor matrix interactions in diabetic nephropathy.

Adult↗
PubMed1996

Significance of anti-nuclear and anti-extracellular matrix autoantibodies for albuminuria in murine lupus nephritis; a longitudinal study on plasma and glomerular eluates in MRL/l mice.

The relationship between autoantibody reactivities and nephritis in systemic lupus erythematosus (SLE) is unclear. We studied MRL/l mice which developed a considerable albuminuria (either mice with short ( < 1 week) or heavy and prolonged (3 weeks) albuminuria) and compared them with non-albuminuric age-matched controls, with young (12 weeks old) non-albuminuric mice and with mice which were followed for 36 weeks and did not develop albuminuria. In a longitudinal prospective study on plasma samples we correlated a variety of anti-nuclear reactivities and reactivities against extracellular matrix (ECM) components, with the onset of albuminuria. We found that at the onset of albuminuria, anti-DNA was higher while anti-nucleosome and anti-H2A/H2B-DNA subnucleosome reactivities were lower compared with age-matched non-albuminuric mice. We also studied glomerular eluates of these mice in ELISA and in indirect immunofluorescence (IF). In the eluates we found with IF that anti-glomerular basement membrane (GBM)-tubular basement membrane (TBM) antibodies were already present in 12-week-old non-albuminuric mice. These eluates showed no anti-nuclear antibodies. In eluates of albuminuric mice more immunoglobulin was deposited, and anti-ECM, anti-DNA and anti-nucleosome reactivities were higher than in eluates of age-matched non-albuminuric mice. The deposition of anti-nucleosome antibodies preceded the deposition of anti-DNA antibodies since they were deposited to a greater extent in mice with a short albuminuria. We conclude that anti-GBM-TBM antibodies are the first autoantibodies that deposit in glomeruli of MRL/l mice at an early age. The onset of albuminuria is associated with additional deposition of both anti-ECM and anti-nuclear (anti-nucleosome and anti-DNA) antibodies, but the difference with non-albuminuric mice seems to be more quantitative than qualitative.

Albuminuria↗
PubMed1996

Elastase, but not proteinase 3 (PR3), induces proteinuria associated with loss of glomerular basement membrane heparan sulphate after in vivo renal perfusion in rats.

Elastase, but not PR3, induces proteinuria associated with loss of glomerular basement membrane (GBM) heparan sulphate after in vivo renal perfusion in rats. PR3 and elastase are cationic neutral serine proteinases present in the azurophilic granules of polymorphonuclear leucocytes. Release of these proteolytic enzymes along the glomerular capillary wall may induce glomerular injury. Here, we investigated the effects of PR3 and elastase on the induction of proteinuria and glomerular injury after renal perfusion of these enzymes in Brown-Norway rats. Perfusion of active elastase induced a dose-dependent proteinuria 24h after perfusion, while inactivated elastase did not. Perfusion of comparable amounts of active PR3 did not induce proteinuria. Light and electron microscopy showed no morphological abnormalities in any experimental group. However, immunohistology revealed that proteinuria occurring after perfusion of active elastase was associated with a strong reduction in intraglomerular expression of the heparan sulphate side chain and, to a lesser extent, of the protein core of heparan sulphate proteoglycans (HSPG). In vitro, both elastase and PR3 digested HSPG. However, PR3 bound to a lesser extent to HSPG than elastase. We conclude that elastase, but not PR3, induces proteinuria after in vivo renal perfusion. This differential effect probably relates to different binding to the GBM of those enzymes due to differences in their isoelectric points. Degradation of heparan sulfate proteoglycans, leading to the disappearance of their side chains that contribute to the polyanionic structure of the GBM, appears to be involved in the induction of proteinuria after perfusion of elastase.

Animals↗
PubMed1996

In vivo ANA is a fixation artifact: nucleosome-complexed antinucleosome autoantibodies bind to the cell surface and are internalized.

It has been suggested that binding of anti-double-standed DNA antibodies to cell surfaces, followed by internalization and nuclear binding (so called in vivo ANA) is of pathophysiological significance for tissue damage in systemic lupus erythematosus. We have shown before that pathogenic antinuclear antibodies complexed to nucleosomal antigens can bind to heparan sulfate in the glomerular basement membrane in vivo. Because nucleosomes are also reported to bind to the cell surface, we hypothesized that in vivo ANA is a property of antinuclear antibodies bound to nucleosomal antigens. Therefore, we studied three antinucleosome monoclonal antibodies (mAb) that exhibit in vivo ANA as seen by immunofluorescence in mice inoculated intraperitoneally with the hybridoma producing the mAb. The same mAb complexed to nucleosomal antigens after intravenous injection into mice induced in vivo ANA, in contrast to purified noncomplexed mAb. To study this in more detail, we incubated complexed mAb with various cell lines and found binding to the cell surface and subsequent internalization into cytoplasmic vesicles. However, no binding to the nucleus was observed by immunoelectron microscopy (IEM) and confocal laser microscopy. Noncomplexed mAb did not bind to the cell surface. Next, from mice bearing the hybridomas producing the mAb intraperitoneally, a small part of the kidney was snap frozen in liquid N2, fixed with acetone, and studied in immunofluorescence, whereas the remaining part of the kidney was fixed in vivo by renal perfusion with a mixture of 0.01 M sodium periodate, 0.075 M lysine HCl, 0.0375 M Na2HPO4, and 2% paraformaldehyde (PLP) and studied in both immunofluorescence and IEM. In the acetone-fixed kidney sections obtained without in vivo fixation we again observed in vivo ANA. However, after in vivo PLP perfusion fixation, no nuclear binding was found. In IEM, localization in cytoplasmic vesicles was seen. In conclusion, antinucleosome antibodies complexed to nucleosomal antigens can bind to the cell surface and are transported into the cytoplasm, but do not bind to the nucleus. The reported nuclear localization of antinuclear antibodies is caused by a fixation artifact.

Animals↗
PubMed1996

Differential effects of angiotensin II and transforming growth factor beta on the production of heparan sulfate proteoglycan by mesangial cells in vitro.

This study approaches the question of whether angiotensin II (AngII) and transforming growth factor beta (TGF-beta) are important mediators for mesangial heparan sulfate proteoglycan (HSPG) production. This might explain the beneficial effects of angiotensin-converting enzyme inhibitors observed in several kidney diseases independent from their hemodynamic effects. Metabolic-labeling studies revealed that AngII induced a decrease of HSPG synthesis with decreases in N-sulfation of the glycosaminoglycan side chains. ELISA measurements with a heparan sulfate (HS)-specific monoclonal antibody confirmed that AngII decreased HS production. AngII increased TGF-beta production in a dose-dependent fashion. Specific mRNA for the large basement membrane HSPG (perlecan) decreased, whereas mRNA for TGF-beta increased after incubation with AngII. Blockade of the Subtype 1 Ang-II receptor (ATR1) reversed both the effects of AngII on HSPG and TGF-beta production. Coincubation of the mesangial cells with neutralizing antibodies against TGF-beta significantly reduced the production of HS as compared with control and AngII. These results indicate that the decrease in HS synthesis induced by AngII is not mediated by an increase in TGF-beta, but on the contrary, the increase in TGF-beta partially counteracts the inhibition of HS production by AngII. Considering the important role of HSPG in maintaining the glomerular charge barrier, cell proliferation, and matrix interaction, downregulation of the production of this molecule by increased local AngII concentrations could have important consequences, such as albuminuria and matrix expansion.

Adult↗
PubMed1995

Presence of N-unsubstituted glucosamine units in native heparan sulfate revealed by a monoclonal antibody.

Immunohistochemical application of antibodies against heparan sulfate proteoglycan core protein and heparitinase-digested heparan sulfate stubs showed the presence of heparan sulfate proteoglycan in all basement membranes of the rat kidney. However, a monoclonal antibody (JM-403) against native heparan sulfate (van den Born, J., van den Heuvel, L. P. W. J., Bakker, M. A. H., Veerkamp, J. H., Assmann, K. J. M., and Berden, J. H. M. (1992) Kidney Int. 41, 115-123) largely failed to stain tubular basement membranes, suggesting the presence of heparan sulfate chains lacking the specific JM-403 epitope. Heparan sulfate preparations from various sources differed markedly with regard to JM-403 binding, as demonstrated by liquid phase inhibition in enzyme-linked immunosorbent assay, the interaction decreasing with increasing sulfate contents of the polysaccharide. Mapping of the JM-403 epitope indicated that it was dominated by one or more N-unsubstituted glucosamine unit(s), since treatments that destroyed or altered the structure of such units in heparan sulfate preparations (cleavage at N-unsubstituted glucosamine units with HNO2 at pH 3.9 and N-acetylation with acetic anhydride, respectively), abolished antibody binding. Conversely, immunoreactivity could be induced in a (D-glucuronyl-1,4-N-acetyl-D-glucosaminyl-1,4) polysaccharide by the generation of N-unsubstituted glucosamine N-unsubstituted glucosamine in a JM-403-binding heparan sulfate (preparation HS-II from human aorta) was demonstrated by an approximately 3-fold reduction in molecular size following HNO2 (pH 3.9) treatment. Further characterization of the epitope recognized by JM-403, based on enzyme-linked immunosorbent assay inhibition tests with chemically/enzymatically modified polysaccharides, indicated that one or more N-sulfated glucosamine units are invariable present, whereas L-iduronic acid and O-sulfate residues appear to inhibit JM-403 reactivity. It is concluded that the epitope contains one or more N-unsubstituted glucosamine and D-glucuronic acid units and is located in a region of the heparan sulfate chain composed of mixed N-sulfated and N-acetylated disaccharide units.

Animals↗
PubMed1995

Proteoglycan production by human glomerular visceral epithelial cells and mesangial cells in vitro.

Proteoglycans metabolically labelled with [35S]sulphate and [3H]glucosamine or [3H]leucine were isolated from the incubation medium and cell layer of human adult mesangial cells and glomerular visceral epithelial cells using sequential DEAE chromatography purification steps followed by gel-filtration chromatography. The proteoglycan composition of each peak was analysed by treatment with HNO2, chondroitinase ABC or chondroitinase AC followed by chromatography on Sephadex G-50 columns. Heparan sulphate proteoglycan (HSPG) and dermatan sulphate proteoglycan were detected in both the culture medium and cell layer of mesangial cells. Culture medium of glomerular visceral epithelial cells contained HSPG and a second proteoglycan with the properties of a hybrid molecule containing HS and chondroitin sulphate (CS). The cell layer contained HSPG and CSPG. Detailed analysis of the hybrid molecule revealed that it had an apparent molecular mass of 400 kDa. SDS/PAGE of hybrid molecules, after treatment with heparitinase and chondroitinase ABC, revealed a core protein of 80 kDa. Using 1.8% polyacrylamide/0.6% agarose-gel electrophoresis, we deduced that the HS and CS were independently attached to one core protein. Because glomerular-basement-membrane HSPG is thought to be derived from mesangial cells and glomerular visceral epithelial cells and this molecule is involved in several kidney diseases, we investigated its synthesis in more detail. Anti-(rat glomerular-basement-membrane HSPG) monoclonal antibodies (JM403) and anti-(human glomerular-basement-membrane HSPG) polyclonal antibodies (both antibodies known to react with the large basement-membrane HSPG, perlecan) reacted strongly with HSPG obtained from both mesangial cells and glomerular visceral epithelial cells. However, the hybrid molecule did not react with these antibodies, suggesting that the HS side chain and the core protein were different from glomerular-basement-membrane HSPG. To quantify HS we performed an inhibition ELISA using mouse antibodies specific for glomerular-basement-membrane HS glycosaminoglycan side chains. Glomerular visceral epithelial cells produced significantly higher levels of HS (between 197.56 and 269.40 micrograms/72 h per 10(6) cells) than mesangial cells (between 29.8 and 45.5 micrograms/72 h per 10(6) cells) (three different cell lines; n = 3; P < 0.001). HS production by these cells was inhibited by cycloheximide, revealing that it was synthesized de novo. Expression of perlecan mRNA, demonstrated using reverse transcriptase PCR, was different in the two cell types. We conclude that glomerular visceral epithelial cells and mesangial cells have characteristic patterns of proteoglycan production. Glomerular visceral epithelial cells produced a hybrid proteoglycan containing CS and HS independently attached to its core protein.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1995

Selective proteinuria in diabetic nephropathy in the rat is associated with a relative decrease in glomerular basement membrane heparan sulphate.

In the present study we investigated whether glomerular hyperfiltration and albuminuria in streptozotocin-induced diabetic nephropathy in male Wistar-Münich rats are associated with changes in the heparan sulphate content of the glomerular basement membrane. Rats with a diabetes mellitus duration of 8 months, treated with low doses of insulin, showed a significant increase in glomerular filtration rate (p < 0.01) and effective renal plasma flow (p < 0.05), without alterations in filtration fraction or mean arterial blood pressure. Diabetic rats developed progressive albuminuria (at 7 months, diabetic rats (D): 42 +/- 13 vs control rats (C): 0.5 +/- 0.2 mg/24 h, p < 0.002) and a decrease of the selectivity index (clearance IgG/clearance albumin) of the proteinuria (at 7 months, D: 0.20 +/- 0.04 vs C: 0.39 +/- 0.17, p < 0.05), suggesting loss of glomerular basement membrane charge. Light- and electron microscopy demonstrated a moderate increase of mesangial matrix and thickening of the glomerular basement membrane in the diabetic rats. Immunohistochemically an increase of laminin, collagen III and IV staining was observed in the mesangium and in the glomerular basement membrane, without alterations in glomerular basement membrane staining of heparan sulphate proteoglycan core protein or heparan sulphate. Glomerular basement membrane heparan sulphate content, quantitated in individual glomerular extracts by a new inhibition ELISA using a specific anti-glomerular basement membrane heparan sulphate monoclonal antibody (JM403), was not altered (median (range) D: 314 (152-941) vs C: 262 (244-467) ng heparan sulphate/mg glomerulus). However, the amount of glomerular 4-hydroxyproline, as a measure for collagen content, was significantly increased (D: 1665 (712-2014) vs C: 672 (515-1208) ng/mg glomerulus, p < 0.01). Consequently, a significant decrease of the heparan sulphate/4-hydroxyproline ratio (D: 0.21 (0.14-1.16) vs C: 0.39 (0.30-0.47), p < 0.05) was found. In summary, we demonstrate that in streptozotocin-diabetic rats glomerular hyperfiltration and a progressive, selective proteinuria are associated with a relative decrease of glomerular basement membrane heparan sulphate. Functionally, a diminished heparan sulphate-associated charge density within the glomerular basement membrane might explain the selective proteinuria in the diabetic rats.

Albumins↗
PubMed1995

Reduction of heparan sulphate-associated anionic sites in the glomerular basement membrane of rats with streptozotocin-induced diabetic nephropathy.

Heparan sulphate-associated anionic sites in the glomerular basement membrane were studied in rats 8 months after induction of diabetes by streptozotocin and in age- adn sex-matched control rats, employing the cationic dye cuprolinic blue. Morphometric analysis at the ultrastructural level was performed using a computerized image processor. The heparan sulphate specificity of the cuprolinic blue staining was demonstrated by glycosaminoglycan-degrading enzymes, showing that pretreatment of the sections with heparitinase abolished all staining, whereas chondroitinase ABC had no effect. The majority of anionic sites (74% in diabetic and 81% in control rats) were found within the lamina rara externa of the glomerular basement membrane. A minority of anionic sites were scattered throughout the lamina densa and lamina rara interna, and were significantly smaller than those in the lamina rara externa of the glomerular basement membrane (p<0.001 and p<0.01 for diabetic and control rats, respectively). Diabetic rats progressively developed albuminuria reaching 40.3 (32.2-62.0) mg/24 h after 8 months in contrast to the control animals (0.8 (0.2-0.9) mg/24 h, p<0.002). At the same time, the number of heparan sulphate anionic sites and the total anionic site surface (number of anionic sites x mean anionic site surface) in the lamina rara externa of the glomerular basement membrane was reduced by 19% (p<0.021) and by 26% (p<0.02), respectively. Number and total anionic site surface in the remaining part of the glomerular basement membrane (lamina densa and lamina rara interna) were not significantly changed. We conclude that in streptozotocin-diabetic rats with an increased urinary albumin excretion, a reduced heparan sulphate charge barrier/density is found at the lamina rara externa of the glomerular basement membrane.

Albuminuria↗
PubMed1995

No evidence for an independent role of anti-heparan sulphate reactivity apart from anti-DNA in lupus nephritis.

The presence of anti-heparan sulphate (HS) reactivity in serum is closely related to the occurrence of nephritis in patients with systemic lupus erythematosus (SLE). Since patients with lupus nephritis in general also have high titres of anti-DNA antibodies, we wanted to clarify the relationship between anti-HS and anti-DNA reactivity in serum. Therefore, we studied longitudinally six patients with lupus nephritis who experienced 12 exacerbations of their disease, and five SLE patients without nephritis experiencing 10 periods of non-renal disease exacerbations. In addition, we tested single serum samples of another 24 patients obtained during a renal disease exacerbation and 22 sera of patients without nephritis. The sera of all patients were tested for anti-DNA (Farr assay) and anti-HS reactivity (ELISA). We confirmed that SLE patients during renal exacerbations have a significantly higher anti-HS reactivity than patients without nephritis (P < 0.003). In addition, patients with nephritis also had higher titres of anti-DNA antibodies during renal exacerbations than during non-renal exacerbations (P < 0.01). A correlation between anti-DNA and anti-HS reactivity was observed (r = 0.40, P < 0.02), which in itself explains the correlation between nephritis and anti-HS reactivity. Comparing sera from nephritis and non-nephritis patients matched for anti-DNA titre, we found no difference in anti-HS reactivity, and therefore must conclude that the anti-HS reactivity is a direct reflection of anti-DNA reactivity.

Antibodies, Antinuclear↗
PubMed1995

Cyclosporin A reduces albuminuria in experimental anti-GBM nephritis independently from changes in GFR.

Cyclosporin A (CsA) can reduce proteinuria in various forms of human and experimental glomerulonephritis. This antiproteinuric effect of CsA may be the consequence of diminution of immunological damage, a drug-induced decrease of GFR, or changes in permselectivity of the glomerular basement membrane (GBM). We studied the antiproteinuric effect of CsA in the heterologous phase of a passively induced anti-GBM nephritis in the mouse. This passive model is characterized by acute exudative glomerular lesions and a dose-dependent albuminuria. Rabbit anti-mouse GBM antibodies were administered intravenously in C57B110 mice at day 4, after 3 days of pretreatment with either CsA (75 mg/kg body weight) (n = 15) or olive oil (OO, controls, n = 15) orally. CsA did not influence the severity of the histological lesions. Albuminuria was substantially reduced by CsA (CsA 1.6 +/- 1.8; OO 5.6 +/- 3.2 mg/18 h; P < 0.002). There was a considerable concomitant reduction of the GFR by CsA, as measured with a 51Cr-EDTA single-shot plasma clearance technique before (day-1) and during treatment (day 4): GFR ratio day 4/day-1 for CsA, 0.4 +/- 0.1; for OO controls, 1.1 +/- 0.6; P < 0.01. This drug-induced decrease of GFR was prevented by simultaneous treatment with phenoxybenzamine (PB) twice daily 45 micrograms orally for 4 days (GFR ratio day 4/day-1 for PB and CsA, 0.9 +/- 0.4; controls (PB and OO), 1.0 +/- 0.4; P = NS). Although the CsA-induced GFR reduction was prevented, CsA still reduced albuminuria significantly (PB and CsA, 2.2 +/- 1.8; controls (PB and OO), 5.6 +/- 1.8 mg/18 h; P = 0.003).(ABSTRACT TRUNCATED AT 250 WORDS)

Albuminuria↗
PubMed1995

Decrease of heparan sulfate staining in the glomerular basement membrane in murine lupus nephritis.

Recently we found in biopsies of human lupus nephritis a nearly complete loss of heparan sulfate (HS) staining in the glomerular basement membrane (GMB). To clarify the relationship between HS staining and albuminuria in lupus nephritis, we studied MRL/lpr mice with short (< 7 days) or prolonged duration of albuminuria (14-21 days) and compared these with mice of different ages without albuminuria. Kidney sections were stained for mouse immunoglobulin (Ig), HS, heparan sulfate proteoglycan (HSPG)-core protein and laminin in immunofluorescence. In mice with prolonged albuminuria HS staining in the glomerular capillary loops had almost completely disappeared, whereas staining was unaltered in non-albuminuric mice (P = 0.001). In mice with short duration of albuminuria, there was a tendency toward a decrease of HS staining (P = 0.06). The expression of HSPG-core protein and other extra cellular matrix (ECM) components was unaltered in all groups. HS staining correlated inversely with albuminuria (rs = -0.55; P < 0.001) and with staining of Ig deposits in the capillary loops (rs = -0.74; P < 0.001). Despite the nearly complete loss of HS staining in the GBM in mice with prolonged albuminuria, there was no change in glomerular HS content as assessed by agarose electrophoresis and HS inhibition ELISA. We conclude that the development of albuminuria in MRL/lpr mice is accompanied by a loss of HS staining in the GBM, probably due to the masking of HS by deposits of Ig. In vitro studies revealed that autoantibodies complexed to nucleosomal antigens can inhibit the binding of the anti-HS monoclonal antibody to HS. Whether this also occurs in vivo remains to be determined.

Albuminuria↗
PubMed1994

[Tubulointerstitial nephritis caused by mesalazine (5-ASA) agents].

In five patients (4 men aged 34, 20, 22 and 29 years, and a woman of 34 years) tubulo-interstitial nephritis developed during treatment with 5-aminosalicylic acid (5-ASA) containing drugs for colitis ulcerosa, proctocolitis or Crohn's disease. Two patients had an impaired renal function before treatment with 5-ASA medication. In all patients there was only an incomplete recovery of renal function after cessation of the therapy. It is therefore necessary to monitor renal function regularly in patients receiving 5-ASA containing preparations.

Adult↗