The Prevalence of Mesangial Electron-Dense Deposits in PLA2R-Positive Membranous Nephropathy

Nephron ◽  
2021 ◽  
pp. 1-5
Author(s):  
Gabriel Giannini ◽  
Lois J. Arend
Keyword(s):  
Electron Microscopy ◽  
Nephrotic Syndrome ◽  
Membranous Nephropathy ◽  
Immunofluorescence Microscopy ◽  
Common Cause ◽  
Electron Dense Deposit ◽  
Dense Deposit ◽  
Phospholipase A2 Receptor ◽  
Dense Deposits ◽  
Negative Biopsies

<b><i>Introduction:</i></b> Membranous nephropathy (MN) is a common cause of nephrotic syndrome in adults and can be primary or secondary. The antigenic target of antibodies in 70% of primary cases is phospholipase A2 receptor (PLA2R). The presence or absence of mesangial electron-dense deposits has been used to distinguish between primary and secondary MN. Mesangial deposits suggest MN due to lupus, infection, or other causes, though they are reported to occur in approximately 10% of primary MN. Staining for PLA2R is now frequently used for confirming a diagnosis of primary MN. If mesangial deposits predict a secondary cause, they should be more frequent in PLA2R-negative biopsies. <b><i>Methods:</i></b> A review of institutional kidney biopsies between March 2017 and June 2020 identified all cases of MN. Cases with a diagnosis of lupus or near “full-house” staining by immunofluorescence microscopy (IF) were excluded. Light microscopy, IF, and electron microscopy (EM) were performed. PLA2R staining was performed by IF. EM for all cases was reviewed and electron-dense deposit location, distribution, and size were determined. <b><i>Results:</i></b> Ninety-three cases of MN were identified, of which 86 had both PLA2R staining and EM performed. Of these, 51 cases (59%) were positive for PLA2R and 35 (41%) were negative. Mesangial electron-dense deposits were present in 22 (25.6%) of the 86 cases, including 27.5% (14/51) of PLA2R-positive cases and 22.8% (8/35) of PLA2R-negative cases. No difference was seen in size or distribution of deposits, or other features considered suggestive of secondary MN. <b><i>Conclusion:</i></b> PLA2R-negative cases were not more likely to have mesangial deposits than PLA2R-positive cases. Mesangial deposits should not be used as an indicator of secondary MN.

Epitope Mapping of Human α3(IV)NC1-Induced Membranous Nephropathy in Mice

2020 ◽  
Vol 51 (2) ◽  
pp. 99-107 ◽  
Author(s):  
Jia Wang ◽  
Miao Wang ◽  
Zhao Cui ◽  
Ming-hui Zhao
Keyword(s):  
Nephrotic Syndrome ◽  
Electron Microscope ◽  
Membranous Nephropathy ◽  
Epitope Mapping ◽  
Igg Subclass ◽  
Common Cause ◽  
Linear Peptide ◽  
Dense Deposits ◽  
Circulating Antibodies ◽  
Gbm Thickening

Background and Aim: Primary membranous nephropathy (pMN) is the most common cause of nephrotic syndrome in adults. Recent studies suggested that immunization of DBA/1 mice with the main antigen of antiglomerular basement membrane disease (GBM) disease, α3(IV)NC1, could lead to MN lesions. This study aimed to explore the pathogenic epitopes for mouse MN. Methods: Twenty-four linear peptides were synthesized spanning human α3(IV)NC1. Male DBA/1 mice aged 6–8 weeks were immunized with the peptides 200 μg/mouse in Freund’s complete adjuvant subcutaneously and boosted 3 times with the peptides in Freund’s incomplete adjuvant in weeks 3, 5, and 7. The blood and 24-h urine samples were assessed every 2 weeks. The kidneys were examined when the mice were sacrificed at 18 weeks. Results: All the mice immunized with human α3(IV)NC1 and the 24 peptides produced circulating antibodies against the immunogens at 2 weeks and achieved the maximum titers at 8 weeks. About 5/6 (83%) mice immunized with α3(IV)NC1 and (3/6) 50% of the mice immunized with peptide 23 (α3141–154) showed proteinuria at 8–10 weeks and increased continuously. The kidneys showed granular depositions of IgG, C3, and C5b-9 along the glomerular capillary loops. The major IgG subclass was IgG1 (equivalent to human IgG4). GBM thickening with the formation of spikes and subepithelial electron-dense deposits were observed under electron microscope. Conclusion: The linear peptide of α3141–154 could induce clinical and histopathological features of MN in DBA/1 mice, which might give clues to the mechanism of MN in combination with anti-GBM disease.

scholarly journals A novel cytochemical marker for liposome decomposition in lysosomes.

1983 ◽  
Vol 31 (3) ◽  
pp. 404-410 ◽  
Author(s):  
S C Ho ◽  
L Huang
Keyword(s):  
Electron Microscopy ◽  
Enzymatic Reaction ◽  
Chinese Hamster ◽  
Electron Dense Deposit ◽  
Transmission Electron ◽  
Dense Deposit ◽  
Condensed Product ◽  
Dense Deposits ◽  
Indigo Blue ◽  
Cytochemical Marker

The endocytosis of large unilamellar liposomes composed of phosphatidylcholine by the cultured Chinese hamster V-79 cells is demonstrated with electron microscopy cytochemistry. A novel cytochemical marker, 5-Br,4-Cl,3-indolylphosphate (BCIP) is used. This marker is a soluble and colorless substrate for the lysosomal acid phosphatase and can be readily entrapped in liposomes. The product of the enzymatic reaction, 5-Br,4-Cl,3-hydroxy indole, rapidly self-condenses and becomes an insoluble derivative of indigo blue. In thin section transmission electron microscopy, the condensed product appears as electron-dense deposits in the lysosomes. Since the electron-dense deposit only appears when the endocytosed liposomes are delivered to the lysosomes as the result of phagosome-lysosome fusion, this marker provides a unique cytochemical means to reveal those liposomes that are lysosomotropic and are actually decomposed within the lysosomes. No electron-dense deposits are found in the liposome-treated cells in the presence of chloroquine, or a combination of NaN3 and deoxyglucose. As a comparison, we have also used horseradish peroxidase entrapped in liposomes to confirm the endocytic uptake of liposomes. Using a radioactive marker, 125I-labeled lysozyme, entrapped in liposomes, it is shown that about 20-30% of liposome uptake by V-79 cells is due to endocytosis.

Adhesion of Phytophthora palmivora zoospores: electron microscopy of cell attachment and cyst wall fibril formation

1975 ◽  
Vol 18 (1) ◽  
pp. 123-132
Author(s):  
V.O. Sing ◽  
S. Bartnicki-Garcia
Keyword(s):  
Electron Microscopy ◽  
Cell Adhesion ◽  
Cyst Wall ◽  
Cell Attachment ◽  
Sodium Dodecyl ◽  
Film Surface ◽  
Phytophthora Palmivora ◽  
Thin Sections ◽  
Electron Dense Deposit ◽  
Dense Deposit

Zoospores of Phytophthora palmivora adhered to a plastic film surface were examined by electron microscopy. Three stages of adhesion were compared: (1) non-adhesive, unencysted zoospores, (2) adhered incipient cysts, and (3) adhered mature cysts. Thin sections of incipient cysts revealed cells attached to the film surface through the partially discharged contents of the so-called peripheral vesicles; this seems to be the first step in cell adhesion. In mature cysts, the adhesive appeared to have been compacted into an electron-dense deposit binding the cyst wall to the plastic surface. The adhesion zone was also examined in face view after lysing attached incipient cysts with sodium dodecyl sulphate. Cyst wall microfibrils were seen together with an amorphous substance (presumably the adhesive material). The microfibrils were in various stages of formation. Seemingly, adhesion and microfibril formation take place concurrently. The possibility was considered that the material contained in the peripheral vesicles serves in both cell adhesion and microfibril elaboration.

scholarly journals P0338CRUMBS HOMOLOG2-EZRIN SIGNALING INDUCED PODOCYTE INJURY, LEADING TO MINIMAL-CHANGE DISEASE(MCD) AND FOCAL SEGMENTAL GLOMERULOSCLEROSIS(FSGS)

2020 ◽  
Vol 35 (Supplement_3) ◽  
Author(s):  
Ichiro Hada
Keyword(s):  
Electron Microscopy ◽  
Nephrotic Syndrome ◽  
Cell Line ◽  
Focal Segmental Glomerulosclerosis ◽  
Minimal Change Disease ◽  
Immunofluorescence Microscopy ◽  
Minimal Change ◽  
Podocyte Injury ◽  
Heavy Proteinuria ◽  
Foot Process

Abstract Background and Aims The etiology and cellular pathogenesis of podocyte injury leading to minimal-change disease (MCD) and focal segmental glomerulosclerosis (FSGS) remain largely obscure. Genetic mutation of crumbs homolog 2 (CRB2) is a cause of congenital nephrotic syndrome. Type-1 transmembrane proteins including CRB2 transduce outside-in signals that are involved in various cellular events including changes in the cytoskeletal network. The aim of the present study is to determine whether alteration of CRB2-mediated signaling in podocytes causes MCD and FSGS. Method Mice were immunized with a partial recombinant protein including the extracellular part of mouse CRB2. Urinalysis was obtained, and the kidney was subjected to histopathology. Kidney samples were also subjected to immunofluorescence microscopy and glomerular isolation to determine whether activation of the ezrin/radixin/moesin (ERM) family of cross-linkers between plasma membrane proteins and the actin cytoskeleton is involved in the pathogenesis of this nephrotic model. A CRB2-expressing mouse podocyte cell line was generated and incubated with anti-CRB2 antibody, and cell lysates were subjected to immunoblot analysis of ERM phosphorylation. The presence of anti-CRB2 antibody in the serum was determined by Western blot analysis. Results Apparent anti-CRB2 antibody was detected in the serum from 4 weeks onward. Immunized mice developed proteinuria at 4 weeks, which continued at least until 29 weeks. Mice developing extremely heavy proteinuria also developed hematuria from 18 weeks onward. Light microscopy revealed MCD in mice with proteinuria alone and FSGS in mice with heavy proteinuria and hematuria. Immunofluorescence microscopy revealed positive granular IgG staining in podocyte foot processes, but not complement C3. Electron microscopy and immuno-electron microscopy revealed alteration of actin organization associated with prominent foot process effacement. Strong phosphorylation of ezrin was observed in the glomerulus from the proteinuric stage and in the cellular lysates from the CRB2-expressing podocyte cell line incubated with anti-CRB2 antibody. Conclusion The current data revealed that binding of anti-CRB2 antibody to the extracellular domain of CRB2 on the podocyte foot process activated the ezrin-cytoskeleton network, leading to podocyte injury. Our data also indicated that signaling by this one molecular can induce two different phenotypes of glomerular injury: MCD and FSGS. In our model, the signaling was activated by anti-CRB2 antibody, but in patients with nephrotic syndrome the CRB2 ligands remain unknown. Therefore, it will be important to identify the soluble factors interacting with CRB2, which may be novel factors contributing to the pathogenesis of MCD and FSGS.

Membranous glomerulonephritis

2018 ◽  
Author(s):  
Daniel C. Cattran ◽  
Heather N. Reich
Keyword(s):  
Membranous Nephropathy ◽  
Adult Life ◽  
Membranous Glomerulonephritis ◽  
Adult Onset ◽  
Common Cause ◽  
End Stage Renal Failure ◽  
Surface Molecules ◽  
Phospholipase A2 Receptor ◽  
Secondary Membranous Nephropathy ◽  
End Stage

Membranous glomerulonephritis (MGN) is the most common cause of adult-onset nephrotic syndrome, and a common glomerular cause of end-stage renal failure. It is caused by antibodies to podocyte surface molecules, usually autoantibodies. In most patients with primary membranous nephropathy the target is the phospholipase A2 receptor. It is hoped that robust assays for this antibody will help to guide therapy but it has not been possible to test this adequately yet. Primary MGN accounts for about 70% of cases with regional variations. MGN is more common in men than women (approximately 2:1) and its peak incidence is in middle adult life. Secondary membranous nephropathy occurs in lupus and some other immune or autoimmune disorders, in hepatitis B infection, after exposure to some drugs or toxins, and in some cancers.

Cytopathological changes induced by potato spindle tuber viroid in Scopolia sinensis

1981 ◽  
Vol 59 (5) ◽  
pp. 677-682 ◽  
Author(s):  
Y. C. Paliwal ◽  
R. P. Singh
Keyword(s):  
Potato Spindle Tuber Viroid ◽  
Infected Tissue ◽  
Cell Organelles ◽  
Electron Dense Deposit ◽  
Dense Bodies ◽  
Dense Deposit ◽  
Dense Deposits ◽  
Local Lesions ◽  
Extensive Cell ◽  
In Cells

The mesophyll parenchyma of Scopolia sinensis Hemsl. leaves infected with potato spindle tuber viroid (PSTV) was examined for cytopathological changes. Cells of the systemically infected tissue showed a proliferation of cytoplasmic membranes in the form of sheets or vesicles and generally these membranes and the tonoplast were studded with electron-dense deposits. About 47% of the cells examined contained amorphous electron-dense inclusions in their vacuoles but about 3% of the healthy leaf cells also contained a few such inclusions. The lumen of many mature cells contained small spherical to oval electron-dense bodies interspersed with fibrils. In cells adjoining the local lesions on inoculated leaves, electron-dense bodies were not found and membrane deposits were rare. However, the amorphous inclusions occurred in 52% of these cells examined. Extensive cell wall deposits containing flattened tubules and vesicles were common in cells adjoining local lesions. Only smaller, localized wall deposits were found in cells of the systemically infected tissue and in some cells adjoining local lesions. Cell organelles were generally unaffected in systemically infected tissue except that mitochondria often contained vacuoles filled with an electron-dense deposit. However, degenerating chloroplasts and mitochondria were common in cells adjoining local lesions.

scholarly journals Successful foetal outcome in a patient with primary membranous nephropathy and circulating anti-phospholipid antibodies: A case report

2018 ◽  
Keyword(s):  
Nephrotic Syndrome ◽  
Phospholipase A2 ◽  
Membranous Nephropathy ◽  
Membranous Glomerulonephritis ◽  
Antiphospholipid Antibody ◽  
Antiphospholipid Antibody Syndrome ◽  
Phospholipase A2 Receptor ◽  
Foetal Outcome ◽  
Circulating Autoantibodies ◽  
Patient’S History

There is little information about pregnancy outcomes in patients with active membranous nephropathy (MN), especially those with circulating autoantibodies to M-type phospholipase A2 receptor (PLA2R), the major autoantigen in primary MN. Membranous glomerulonephritis (MGN) represents an immunologically mediated disease characterized by deposition of immune complexes in the glomerular subepithelial space, frequently associated with circulating M-type phospholipase A2 receptor. Nephrotic syndrome (massive proteinuria and hypoalbuminemia) at diagnosis predicts poor prognosis. Pregnancy with active MGN is high risk for foetal loss, intrauterine growth restriction, and pre-eclampsia, and may worsen maternal renal function, especially with the presence of antiphospholipid antibody syndrome (APLA). We report a 23-year-old gravida in her first pregnancy, suffering from MGN and severe nephrotic syndrome, complicated by APLA syndrome. The patient was treated with enoxaparin, aspirin azathioprine, and Prednisone for a short time, in addition to furosemide and albumin intravenously. She was delivered at 30 weeks due to deteriorating maternal and foetal conditions. A successful neonatal and maternal outcome was achieved in this case. The patient's history revealed thrombocytopenia and APLA syndrome and continues to be treated chronically with enoxaparin. Kidney biopsy performed after delivery showed membranous MGN stage II-III. Herein, we present a case of successful pregnancy and foetal outcome in a young woman with APLA syndrome and MN. Keywords: Membranous GN, Nephrotic Syndrome, Anti-Phospholipid Antibodies.

scholarly journals An Overview of Molecular Mechanism of Nephrotic Syndrome

2012 ◽  
Vol 2012 ◽  
pp. 1-6 ◽  
Author(s):  
Juliana Reis Machado ◽  
Laura Penna Rocha ◽  
Precil Diego Miranda de Menezes Neves ◽  
Eliângela de Castro Cobô ◽  
Marcos Vinícius Silva ◽  
...  
Keyword(s):  
Nephrotic Syndrome ◽  
Membranous Nephropathy ◽  
Epithelial Mesenchymal Transition ◽  
Membrane Damage ◽  
Membranous Glomerulonephritis ◽  
Basal Membrane ◽  
Experimental Models ◽  
Mesenchymal Transition ◽  
Disease Occurrence ◽  
Phospholipase A2 Receptor

Podocytopathies (minimal change disease (MCD) and focal segmental glomerulosclerosis (FSGS)) together with membranous nephropathy are the main causes of nephrotic syndrome. Some changes on the expression of nephrin, podocin, TGF-β, and slit diaphragm components as well as transcription factors and transmembrane proteins have been demonstrated in podocytopathies. Considering the pathogenesis of proteinuria, some elucidations have been directed towards the involvement of epithelial-mesenchymal transition. Moreover, the usefulness of some markers such as TGF-β1, nephrin, synaptopodin, dystroglycans, and malondialdehyde have been determined in the differentiation between MCD and FSGS. Experimental models and human samples indicated an essential role of autoantibodies in membranous glomerulonephritis, kidney damage, and proteinuria events. Megalin and phospholipase-A2-receptor have been described as antigens responsible for the formation of the subepithelial immune complexes and renal disease occurrence. In addition, the complement system seems to play a key role in basal membrane damage and in the development of proteinuria in membranous nephropathy. This paper focuses on the common molecular changes involved in the development of nephrotic proteinuria.

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