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Nephrology, Dialysis, Transplantation :... Aug 2022Galactose-deficient immunoglobulin A1 (Gd-IgA1) plays a crucial role in the development of IgA nephropathy (IgAN). However, the pathological role of Gd-IgA1-containing...
BACKGROUND
Galactose-deficient immunoglobulin A1 (Gd-IgA1) plays a crucial role in the development of IgA nephropathy (IgAN). However, the pathological role of Gd-IgA1-containing immune complexes (ICs) and the mechanism of deposition in the mesangial region remain unclear.
METHODS
To examine the deposition of Gd-IgA1-containing ICs in the mesangial region through glomerular endothelial cell injury, we evaluated the alteration of renal microvascular endothelial glycocalyx in nude mice injected with Gd-IgA1-IgG ICs. Human renal glomerular endothelial cells (HRGECs) were used to assess the potential capacity of Gd-IgA1-IgG ICs to activate endothelial cells.
RESULTS
Nude mice injected with Gd-IgA1-containing ICs showed podocyte and endothelial cell injuries, with IgA, IgG and C3 depositions in glomerular capillaries and the mesangium. Moreover, albuminuria and hematuria were induced. Real-time glycocalyx imaging showed that renal microvascular glycocalyx was decreased immediately after injection of Gd-IgA1-containing ICs and then mesangial IgA deposition was increased. After coculture of Gd-IgA1-containing ICs with HRGECs, messenger RNA expression levels of endothelial adhesion molecules and proinflammatory mediators were upregulated significantly.
CONCLUSION
Gd-IgA1-IgG ICs had a high affinity for glomerular endothelial cells, which resulted in glomerular filtration barrier dysfunction mediated by glycocalyx loss. Furthermore, Gd-IgA1-IgG ICs accelerated the production of adhesion factors and proinflammatory cytokines in glomerular endothelial cells. The glomerular endothelial cell injury induced by Gd-IgA1-containing ICs may enhance the permeability of Igs in the mesangial region and subsequent inflammatory responses in the pathogenesis of IgAN.
Topics: Animals; Antigen-Antibody Complex; Endothelial Cells; Galactose; Glomerulonephritis, IGA; Humans; Immunoglobulin A; Immunoglobulin G; Mice; Mice, Nude
PubMed: 35746884
DOI: 10.1093/ndt/gfac204 -
CEN Case Reports Feb 2023Immunoglobulin G (IgG) nephropathy refers to a rare group of diseases characterized by deposits of IgG in the mesangial region. However, IgG nephropathy is controversial...
Immunoglobulin G (IgG) nephropathy refers to a rare group of diseases characterized by deposits of IgG in the mesangial region. However, IgG nephropathy is controversial as a single disease entity, and its pathogenesis remains to be elucidated. In the present report, we discuss a case of IgG nephropathy in which we observed activation of the classical complement pathway.A 47-year-old woman was admitted to our hospital with nephrotic syndrome. Light-microscopic examination revealed neither proliferative nor sclerotic lesions in the glomeruli. However, unusual and large deposits were observed in the paramesangial area. An immunofluorescence study revealed predominant IgG and C1q and slight C3 deposits in the paramesangial area, suggesting immune-complex-type glomerular disease. An electron microscopic study also revealed different sizes of non-organized electron-dense deposits with a similar pattern of distribution, which were accompanied by foot process effacement. Clinically, there was no evidence of systemic diseases, such as infectious or autoimmune diseases (including systemic lupus erythematosus). Based on these findings, she was diagnosed with IgG nephropathy and treated with prednisolone. Steroid therapy was effective, and complete remission was maintained.Additional immunological examination revealed that IgG deposits were polyclonal and consisted mainly of the IgG1 and IgG3 subclasses. Furthermore, staining was positive for C4d and C5b-9. The present findings indicate that the pathogenesis of IgG nephropathy in our patient may have involved activation of the classical complement pathway.
Topics: Female; Humans; Middle Aged; Immunoglobulin G; Complement Pathway, Classical; Kidney Glomerulus; Nephrotic Syndrome; Glomerular Mesangium
PubMed: 35711019
DOI: 10.1007/s13730-022-00710-5 -
The Journal of Pathology Sep 2022In Alport mice, activation of the endothelin A receptor (ET R) in mesangial cells results in sub-endothelial invasion of glomerular capillaries by mesangial filopodia....
Glomerular basement membrane deposition of collagen α1(III) in Alport glomeruli by mesangial filopodia injures podocytes via aberrant signaling through DDR1 and integrin α2β1.
In Alport mice, activation of the endothelin A receptor (ET R) in mesangial cells results in sub-endothelial invasion of glomerular capillaries by mesangial filopodia. Filopodia deposit mesangial matrix in the glomerular basement membrane (GBM), including laminin 211 which activates NF-κB, resulting in induction of inflammatory cytokines. Herein we show that collagen α1(III) is also deposited in the GBM. Collagen α1(III) localized to the mesangium in wild-type mice and was found in both the mesangium and the GBM in Alport mice. We show that collagen α1(III) activates discoidin domain receptor family, member 1 (DDR1) receptors both in vitro and in vivo. To elucidate whether collagen α1(III) might cause podocyte injury, cultured murine Alport podocytes were overlaid with recombinant collagen α1(III), or not, for 24 h and RNA was analyzed by RNA sequencing (RNA-seq). These same cells were subjected to siRNA knockdown for integrin α2 or DDR1 and the RNA was analyzed by RNA-seq. Results were validated in vivo using RNA-seq from RNA isolated from wild-type and Alport mouse glomeruli. Numerous genes associated with podocyte injury were up- or down-regulated in both Alport glomeruli and cultured podocytes treated with collagen α1(III), 18 of which have been associated previously with podocyte injury or glomerulonephritis. The data indicate α2β1 integrin/DDR1 co-receptor signaling as the dominant regulatory mechanism. This may explain earlier studies where deletion of either DDR1 or α2β1 integrin in Alport mice ameliorates renal pathology. © 2022 Boys Town National Research Hospital. The Journal of Pathology published by John Wiley & Sons Ltd on behalf of The Pathological Society of Great Britain and Ireland.
Topics: Animals; Basement Membrane; Collagen Type III; Collagen Type IV; Discoidin Domain Receptor 1; Glomerular Basement Membrane; Humans; Integrin alpha2beta1; Mice; Mice, Knockout; Nephritis, Hereditary; Podocytes; Pseudopodia; RNA
PubMed: 35607980
DOI: 10.1002/path.5969 -
Indian Journal of Nephrology 2022C4d is a biomarker of the complement cascade and has a primary role in the diagnosis of antibody-mediated rejection in solid organ transplantation. The present study was...
INTRODUCTION
C4d is a biomarker of the complement cascade and has a primary role in the diagnosis of antibody-mediated rejection in solid organ transplantation. The present study was undertaken to investigate the role of C4d in the diagnosis and prognosis of native renal diseases.
METHODS
An observational cross-sectional study was conducted in the Department of Pathology from September 2017 to September 2019. In this study, we applied C4d staining by immunohistochemistry in 51 native renal biopsies. Semiquantitative scoring was done on the basis of intensity of C4d staining along the glomerular capillary wall (0-3) and mesangium (0-3), tubules (0-3), and arteries (0-3). These individual scores were added to get the total C4d score (0-12) which was correlated with chronicity index, serum urea and creatinine levels. Glomerular C4d score was correlated with 24 h urinary protein as well as with immunofluorescence deposition of immunoglobulins and complements.
RESULTS
We found a linear positive correlation ( < 0.05) between the total C4d score and serum creatinine; tubular C4d score and serum creatinine; and glomerular C4d score along capillary wall and 24 h urinary protein. A positive correlation ( < 0.05) was found between glomerular C4d score along the capillary wall with immunofluorescence deposits of immunoglobulins and complements, suggesting the efficacy of C4d as a surrogate marker in the diagnosis of native renal diseases.
CONCLUSIONS
C4d deposition is associated with a poor prognosis in renal diseases and an accelerated deterioration of renal function. It also plays a role as a surrogate marker in diagnosis of native renal diseases.
PubMed: 35603116
DOI: 10.4103/ijn.IJN_251_20 -
Scientific Reports May 2022Diabetic kidney disease is a consequence of hyperglycemia and other complex events driven by early glomerular hemodynamic changes and a progressive expansion of the...
Diabetic kidney disease is a consequence of hyperglycemia and other complex events driven by early glomerular hemodynamic changes and a progressive expansion of the mesangium. The molecular mechanisms behind the pathophysiological alterations of the mesangium are yet to be elucidated. This study aimed at investigating whether lipid signaling might be the missing link. Stimulation of human mesangial cells with high glucose primed the inflammasome-driven interleukin 1 beta (IL-1β) secretion, which in turn stimulated platelet-derived growth factor (PDGF-BB) release. Finally, PDGF-BB increased IL-1β secretion synergistically. Both IL-1β and PDGF-BB stimulation triggered the formation of phosphorylated sphingoid bases, as shown by lipidomics, and activated cytosolic phospholipase cPLA2, sphingosine kinase 1, cyclooxygenase 2, and autotaxin. This led to the release of arachidonic acid and lysophosphatidylcholine, activating the secretion of vasodilatory prostaglandins and proliferative lysophosphatidic acids. Blocking cPLA2 release of arachidonic acid reduced mesangial cells proliferation and prostaglandin secretion. Validation was performed in silico using the Nephroseq database and a glomerular transcriptomic database. In conclusion, hyperglycemia primes glomerular inflammatory and proliferative stimuli triggering lipid metabolism modifications in human mesangial cells. The upregulation of cPLA2 was critical in this setting. Its inhibition reduced mesangial secretion of prostaglandins and proliferation, making it a potential therapeutical target.
Topics: Arachidonic Acid; Becaplermin; Cells, Cultured; Glomerular Mesangium; Humans; Hyperglycemia; Lipid Metabolism; Mesangial Cells; Phospholipases A2; Phospholipases A2, Cytosolic; Prostaglandins
PubMed: 35513427
DOI: 10.1038/s41598-022-10907-4 -
Kidney International Reports Apr 2022Primary IgA nephropathy (IgAN) with light chain λ restriction in the mesangial deposits (IgAN-λ) has unique immunofluorescence (IF) features. Nevertheless, its...
INTRODUCTION
Primary IgA nephropathy (IgAN) with light chain λ restriction in the mesangial deposits (IgAN-λ) has unique immunofluorescence (IF) features. Nevertheless, its clinicopathology and prognosis are still ambiguous.
METHODS
From January 2002 to December 2020, the clinical and pathologic data of 3872 patients who were diagnosed with having primary IgAN by renal biopsy in our hospital were reviewed. A total of 187 patients who met the selection criteria for IgAN-λ were enrolled to conduct a retrospective single-center study. The selection criteria were that IF features conform to light chain λ restriction in the mesangial deposits. According to age, sex, renal function (estimated glomerular filtration rate [eGFR]), and follow-up time, the control group was constructed with 1:3 matched cases of IgAN. The clinicopathologic and prognostic differences between the 2 groups were analyzed.
RESULTS
Compared with that in the IgAN group, the serum fibrinogen level in the IgAN-λ group was significantly higher ( < 0.001). Furthermore, cluster analysis indicated the different clusters involved in fibrinogen between the IgAN-λ and IgAN groups and that fibrinogen is associated with factors reflecting renal function in IgAN-λ but proteinuria levels in IgAN. The light chain λ deposit in the mesangium is associated with the formation of crescents in those with IgAN-λ, but complement C3 deposition in those with IgAN. Our Kaplan-Meier analysis revealed that the prognosis of the IgAN-λ group was significantly worse than that of the IgAN group within >6 years of follow-up ( = 0.02). The multi-Cox analysis revealed that the light chain λ restriction in the mesangial deposits was an independent risk factor for poor outcomes (eGFR decreased from the baseline ≥ 30% continuously or reached end-stage renal disease [ESRD] or died).
CONCLUSION
The prognosis of those with IgAN-λ was worse than that of those with IgAN, which may be attributed to the light chain λ restriction in the mesangial deposits inducing a significant systemic inflammation manifested as severe clinical features and frequent crescent.
PubMed: 35497802
DOI: 10.1016/j.ekir.2022.01.1053 -
Frontiers in Pediatrics 2022Perinatal complications, such as prematurity and intrauterine growth restriction, are associated with increased risk of chronic kidney disease. Although often associated...
BACKGROUND
Perinatal complications, such as prematurity and intrauterine growth restriction, are associated with increased risk of chronic kidney disease. Although often associated with reduced nephron endowment, there is also evidence of increased susceptibility for sclerotic changes and podocyte alterations. Preterm birth is frequently associated with chorioamnionitis, though studies regarding the effect of chorioamnionitis on the kidney are scarce. In this study, we aim to unravel the consequences of premature birth and/or perinatal inflammation on kidney development using an ovine model.
METHODS
In a preterm sheep model, chorioamnionitis was induced by intra-amniotic injection of lipopolysaccharide (LPS) at either 2, 8, or 15 days prior to delivery. Control animals received intra-amniotic injections of sterile saline. All lambs were surgically delivered at 125 days' gestation (full term is 150 days) and immediately euthanized for necropsy. Kidneys were harvested and processed for staining with myeloperoxidase (MPO), Wilms tumor-1 (WT1) and alpha-smooth muscle actine (aSMA). mRNA expression of tumor necrosis factor alpha (), Interleukin 10 (), desmin (), Platelet derived growth factor beta (), Platelet derived growth factor receptor beta (PDGFRB), synaptopodin (SYNPO), and transforming growth factor beta () was measured using quantitative PCR.
RESULTS
Animals with extended (but not acute) LPS exposure had an inflammatory response in the kidney. MPO staining was significantly increased after 8 and 15 days ( = 0.003 and = 0.008, respectively). Expression of ( = 0.016) and ( = 0.026) transcripts was increased, peaking on day 8 after LPS exposure. Glomerular aSMA and expression of TGFB was increased on day 8, suggesting pro-fibrotic mesangial activation, however, this was not confirmed with PDFGB or PDGFRB. The number of WT1 positive nuclei in the glomerulus, as well as expression of synaptopodin, decreased, indicating podocyte injury.
CONCLUSION
We report that, in an ovine model of prematurity, LPS-induced chorioamnionitis leads to inflammation of the immature kidney. In addition, this process was associated with podocyte injury and there are markers to support pro-fibrotic changes to the glomerular mesangium. These data suggest a potential important role for antenatal inflammation in the development of preterm-associated kidney disease, which is frequent.
PubMed: 35444963
DOI: 10.3389/fped.2022.796702 -
BMC Nephrology Apr 2022The flare of immune-mediated disease following coronavirus disease of 2019 (COVID-19) vaccination is a rare adverse event following immunization. De novo, as well as...
BACKGROUND
The flare of immune-mediated disease following coronavirus disease of 2019 (COVID-19) vaccination is a rare adverse event following immunization. De novo, as well as relapsing IgA nephropathy (IgAN) cases, have been reported following either mRNA-1273 (Moderna) or BNT162b2 (Pfizer-BioNTech) vaccination. To our knowledge, the majority of IgAN relapses did not result in severe acute kidney injury (AKI) and resolved spontaneously.
CASE PRESENTATION
This is a case of a 54-year-old female with a previous diagnosis of IgAN who developed IgAN relapse following the second dose of Moderna vaccine. Gross hematuria developed 2 days after vaccination, which was accompanied by significant AKI. Kidney biopsy showed mild tubular atrophy and IgA staining in mesangium without crescent formation. Significant improvement in serum creatinine (Cr) was observed on day 10 after initiating prednisone. Cr came back to normal within 3 months after initiating corticosteroid.
CONCLUSION
COVID-19 vaccination is associated with a flare of IgAN that may cause significant AKI. Steroid therapy is associated with recovery. IgAN flare after COVID-19 vaccination should be closely monitored to elucidate any adverse effect associated with the novel vaccine.
Topics: Acute Kidney Injury; BNT162 Vaccine; COVID-19; COVID-19 Vaccines; Chronic Disease; Female; Glomerulonephritis, IGA; Humans; Middle Aged; Recurrence; Vaccination
PubMed: 35392838
DOI: 10.1186/s12882-022-02769-9 -
Kidney360 Aug 2021IgA nephropathy (IgAn), defined by the pre dominant de position of IgA in the glomerular mesangium, is the most common form of GN throughout the world. However, its... (Review)
Review
IgA nephropathy (IgAn), defined by the pre dominant de position of IgA in the glomerular mesangium, is the most common form of GN throughout the world. However, its incidence, sex distribution, clinical presentation, and progression and pathogenic initiating factors are largely variable and do not fit such a simple definition. To assess the heterogeneity of this disease, we recently conducted a clinical survey on the presentation and clinical management of patients with IgAn in Europe and Japan. This clinical survey highlights similarities and differences in patients from different cont inents. The survey revealed obvious differences between nations in the frequency of gastrointestinal complications, including inflammatory bowel diseases (IBD) and celiac disease, which were more frequent in European patients. Such findings are compatible with susceptibility loci related to intestinal immunity and IBD in recent genome wide association studies (GWAS) on IgAn. However, most of the molecules in these mucosal-related loci fulfill the immunologic function not only of gut-associated lymphoid tissue (GALT), but also nasopharyngeal/bronchial-associated lymphoid tissues (NALT/BALT). Indeed, a similar frequency of macrohematuria coinciding with upper respiratory infection, a hallmark manifestation of this disease, was found in the survey, emphasizing the pathogenic roles of these molecules in the NALT/BALT of patients with IgAn. Recent experimental and clinical studies including GWAS on multiple common infections and IBD indicate immune crosstalk between GALT and NALT/BALT, and some related mediators, such as TNF superfamily ligands (APRIL/BAFF). This review explains the epidemiologic heterogeneity of this disease with the clinical survey, and discusses race and sex-dependent molecular mechanisms.
Topics: Celiac Disease; Genome-Wide Association Study; Glomerular Mesangium; Glomerulonephritis, IGA; Humans; Immunity, Mucosal
PubMed: 35369654
DOI: 10.34067/KID.0002972021 -
CEN Case Reports Nov 2022Light chain deposition disease (LCDD) is a form of monoclonal gammopathy of renal significance. The diagnosis is based on the immunofluorescence (IF) findings of linear...
Light chain deposition disease (LCDD) is a form of monoclonal gammopathy of renal significance. The diagnosis is based on the immunofluorescence (IF) findings of linear monoclonal light chain staining of basement membranes throughout the kidney, which appear as non-organized, granular punctate to powdery electron dense deposits by electron microscopy (EM). Although "LCDD by IF only" without EM deposits has been well-described, LCDD identified by EM with negative IF is very rare and hardly mentioned in the literature. Herein we describe a case of lambda-type LCDD that appeared negative by IF and showed light microscopic findings of nodular glomerulosclerosis, which was initially attributed to the patient's history of significant tobacco use and uncontrolled hypertension. However, EM later showed powdery electron dense material in focal glomerular and tubular basement membranes and mesangium. Subsequent bone marrow analysis revealed greater than 60% lambda-restricted plasma cells. We report this case to illustrate that within the differential diagnosis of nodular sclerosis, monoclonal immunoglobulin deposition disease (MIDD) should remain in the differential even if immunofluorescence appears negative as EM can prove to be crucial in identifying cases of MIDD.
Topics: Humans; Diabetic Nephropathies; Immunoglobulin Light Chains; Paraproteinemias; Multiple Myeloma; Microscopy, Electron; Smoking
PubMed: 35316527
DOI: 10.1007/s13730-022-00698-y