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Kidney360 May 2023
Topics: Kidney Glomerulus; Glomerular Mesangium; Microvessels; Machine Learning
PubMed: 37229727
DOI: 10.34067/KID.0000000000000111 -
Cureus Apr 2023Focal segmental glomerulosclerosis (FSGS) and IgA nephropathy are among the most common glomerular disorders. FSGS is characterized by focal scarring affecting less than...
Focal segmental glomerulosclerosis (FSGS) and IgA nephropathy are among the most common glomerular disorders. FSGS is characterized by focal scarring affecting less than 50% of glomeruli while IgA nephropathy is characterized by the deposition of IgA in the mesangium of glomeruli. The presence of both of these diseases in a single patient is uncommon, but the presence of both in a young individual with no predisposing factors is exceedingly rare. As such, our case report outlines the unusual presentation of both of these disorders in a young Hispanic female with no known risk factors.
PubMed: 37159790
DOI: 10.7759/cureus.37212 -
Frontiers in Immunology 2023Immunoglobulin A (IgA) is the most abundant isotype of antibodies, provides a first line of defense at mucosal surfaces against pathogens, and thereby contributes to... (Review)
Review
Immunoglobulin A (IgA) is the most abundant isotype of antibodies, provides a first line of defense at mucosal surfaces against pathogens, and thereby contributes to mucosal homeostasis. IgA is generally considered as a non-inflammatory antibody because of its main function, neutralizing pathogenic virus or bacteria. Meanwhile, IgA can induce IgA-mediated diseases, such as IgA nephropathy (IgAN) and IgA vasculitis. IgAN is characterized by the deposition of IgA and complement C3, often with IgG and/or IgM, in the glomerular mesangial region, followed by mesangial cell proliferation and excessive synthesis of extracellular matrix in glomeruli. Almost half a century has passed since the first report of patients with IgAN; it remains debatable about the mechanism how IgA antibodies selectively bind to mesangial region-a hallmark of IgAN-and cause glomerular injuries in IgAN. Previous lectin- and mass-spectrometry-based analysis have revealed that IgAN patients showed elevated serum level of undergalactosylated IgA1 in O-linked glycans of its hinge region, called galactose-deficient IgA1 (Gd-IgA1). Thereafter, numerous studies have confirmed that the glomerular IgA from IgAN patients are enriched with Gd-IgA1; thus, the first hit of the current pathogenesis of IgAN has been considered to increase circulating levels of Gd-IgA1. Recent studies, however, demonstrated that this aberrant glycosylation alone is not sufficient to disease onset and progression, suggesting that several additional factors are required for the selective deposition of IgA in the mesangial region and induce nephritis. Herein, we discuss the current understanding of the characteristics of pathogenic IgA and its mechanism of inducing inflammation in IgAN.
Topics: Humans; Glomerulonephritis, IGA; Immunoglobulin A; Glomerular Mesangium; IgA Vasculitis
PubMed: 37114051
DOI: 10.3389/fimmu.2023.1165394 -
Medicine Apr 2023Polycythemia vera (PV) is a myeloproliferative neoplasm which is characterized by excessive production of erythrocytes as well as myeloid and megakaryocytic...
BACKGROUND
Polycythemia vera (PV) is a myeloproliferative neoplasm which is characterized by excessive production of erythrocytes as well as myeloid and megakaryocytic proliferation. PV associated with IgA nephropathy (IgAN) has rarely been reported in the literature. The long-term renal prognosis of these patients is unknown.
METHODS
Clinical and pathological characteristics of 7 patients with renal biopsy-proven IgAN associated with PV were retrospectively analyzed.
RESULTS
The 7 patients were all males, with a mean age of 49.1 ± 18.8 years when admitted to our hospital. Systemic symptoms include: hypertension in case 2, 3, 5, and 6, splenomegaly in case 2, 4, and 5, and multiple lacunar infarction in case 6. Bone marrow biopsy test revealed relative erythroid hyperplasia and atypical megakaryocyte proliferation which consistent with a chronic myeloproliferative neoplasm. All patients had JAK2V617F and BCR-ABL tested, and JAK2V617F positive in 2 patients. Mild mesangial proliferation was observed in 5 patients and moderate/severe mesangial proliferation in 2patients. Immunofluorescence mainly showed diffuse granular deposition of dominant IgA in mesangium. After follow-up of 56.7 ± 44.0 months, hemoglobin level was 144 ± 29 g/L and hematocrit lever was 0.470 ± 0.03, compared with 187 ± 29 g/L and 0.563 ± 0.087 respectively when admitted to our hospital. The urine protein was 0.85 ± 0.64 g/24 h compared with 3.97 ± 4.68 g/24 h. Case 3 progressed to end stage renal disease and had received hemodialysis for 5 years before renal transplantation.
CONCLUSIONS
The results of this study showed that PV associated with IgAN mainly occurs in males and is often accompanied by hematuria and mild-to-moderate renal insufficiency. The long-term prognosis was good for most patients, and few progressed relatively quickly to end stage renal disease.
Topics: Male; Humans; Adult; Middle Aged; Aged; Glomerulonephritis, IGA; Polycythemia Vera; Retrospective Studies; East Asian People; Kidney Failure, Chronic; Myeloproliferative Disorders
PubMed: 37026962
DOI: 10.1097/MD.0000000000033493 -
BMC Rheumatology Apr 2023The nature of the deposits in immune-mediated glomerulonephritis with a membranous pattern and masked IgG-Kappa deposits (MGMID) remains still to be elucidated.
BACKGROUND
The nature of the deposits in immune-mediated glomerulonephritis with a membranous pattern and masked IgG-Kappa deposits (MGMID) remains still to be elucidated.
CASE PRESENTATION
We present a case of 33-year-old woman developing a continuous asymptomatic proteinuria (0.8-1 g/24 h) with no overt connective tissue diseases. She tested positive at high titers for SSA antibodies (Ro52 838 UI/mL, Ro60 2716 UI/mL) and at the kidney biopsy histological findings were compatible with an immune-mediated glomerulonephritis with a membranous pattern and masked IgG-Kappa deposits. Also, we demonstrated a positive immunohistochemistry staining for anti-Ro52-SSA antibodies, with a granular positivity in mesangium and along rare glomerular capillaries. To date, only one case of a patient with overt diagnosis of Sjögren's syndrome with MGMID has been described but a pathogenic role for SSA and SSB antibodies has never been proven.
CONCLUSIONS
In this case, we described for the first time by immunohistochemistry a Ro52+ granular positivity in the mesangium and glomerular capillaries, potentially paving the way for a better understanding of MGMID.
PubMed: 37016425
DOI: 10.1186/s41927-023-00330-1 -
Frontiers in Medicine 2023Immunoglobulin A nephropathy (IgAN) is the most common primary glomerulonephritis and the leading cause of kidney failure in the world. The current widely accepted... (Review)
Review
Immunoglobulin A nephropathy (IgAN) is the most common primary glomerulonephritis and the leading cause of kidney failure in the world. The current widely accepted framework for its pathogenesis is the "multi-hit hypothesis." In this review, we mainly discussed the intrarenal inflammation in IgAN, which is initiated by immune complex deposition with complement molecule activation, by focusing on four main types of cells in nephrons including mesangial cells, endothelial cells, podocytes, and tubular epithelial cells (TECs). Galactose-deficient IgA1 (Gd-IgA1)-containing immune complexes deposit in the mesangium and activate complement molecules and mesangial cells. Activation of mesangial cells by Gd-IgA1 deposition with enhanced cellular proliferation, extracellular matrix (ECM) expansion, and inflammatory response plays a central role in the pathogenesis of IgAN. Regional immune complex deposition and mesangial-endothelial crosstalk result in hyperpermeability of endothelium with loss of endothelial cells and infiltration barrier proteins, and recruitment of inflammatory cells. Podocyte damage is mainly derived from mesangial-podocyte crosstalk, in which tumor necrosis factor-α (TNF-α), transforming growth factor-β (TGF-β), renin-angiotensin-aldosterone system (RAAS), and micro-RNAs are the major players in podocyte apoptosis and disorganization of slit diaphragm (SD) related to proteinuria in patients with IgAN. In addition to filtrated proteins into tubulointerstitium and mesangial-tubular crosstalk involved in the injury of TECs, retinoic acid has been discovered innovatively participating in TEC injury.
PubMed: 36968836
DOI: 10.3389/fmed.2023.1128393 -
Science Advances Mar 2023Immunoglobulin A (IgA) nephropathy (IgAN) is the most common type of primary glomerulonephritis, often progressing to renal failure. IgAN is triggered by IgA deposition...
Immunoglobulin A (IgA) nephropathy (IgAN) is the most common type of primary glomerulonephritis, often progressing to renal failure. IgAN is triggered by IgA deposition in the glomerular mesangium by an undefined mechanism. Here, we show that grouped ddY (gddY) mice, a spontaneous IgAN model, produce serum IgA against mesangial antigens, including βII-spectrin. Most patients with IgAN also have serum anti-βII-spectrin IgA. As in patients with IgAN, IgA plasmablasts accumulate in the kidneys of gddY mice. IgA antibodies cloned from the plasmablasts carry substantial V-region mutations and bind to βII-spectrin and the surface of mesangial cells. These IgAs recognize transfected and endogenous βII-spectrin exposed on the surface of embryonic kidney-derived cells. Last, we demonstrate that the cloned IgA can bind selectively to glomerular mesangial regions in situ. The identification of IgA autoantibody and its antigen in IgAN provides key insights into disease onset and redefines IgAN as a tissue-specific autoimmune disease.
Topics: Mice; Animals; Glomerulonephritis, IGA; Mesangial Cells; Spectrin; Immunoglobulin A; Autoantibodies
PubMed: 36947618
DOI: 10.1126/sciadv.add6734 -
Nan Fang Yi Ke Da Xue Xue Bao = Journal... Feb 2023To study the toxic effects of short-term exposure to gossypol on the testis and kidney in mice and whether these effects are reversible.
OBJECTIVE
To study the toxic effects of short-term exposure to gossypol on the testis and kidney in mice and whether these effects are reversible.
METHODS
Twenty 7 to 8-week-old male mice were randomized into blank control group, solvent control group, gossypol treatment group and drug withdrawal group. In the former 3 groups, the mice were subjected to daily intragastric administration of 0.3 mL of purified water, 1% sodium carboxymethylcellulose solution, and 30 mg/mL gossypol solution for 14 days, respectively; In the drug withdrawal group, the mice were treated with gossypol solution in the same manner for 14 days followed by treatment with purified water for another 14 days. After the last administration, the mice were euthanized and tissue samples were collected. The testicular tissue was weighed and observed microscopically with HE and PAS staining; the kidney tissue was stained with HE and examined for mitochondrial ATPase activity.
RESULTS
Compared with those in the control group, the mice with gossypol exposure showed reduced testicular seminiferous epithelial cells with rounded seminiferous tubules, enlarged space between the seminiferous tubules, interstitium atrophy of the testis, and incomplete differentiation of the spermatogonia. The gossypol-treated mice also presented with complete, non-elongated spermatids, a large number of cells in the state of round spermatids, and negativity for acrosome PAS reaction; diffuse renal mesangial cell hyperplasia, increased mesangial matrix, and adhesion of the mesangium to the wall of the renal capsule were observed, with significantly shrinkage or even absence of the lumens of the renal capsules and reduced kidney mitochondrial ATPase activity. Compared with the gossypol-treated mice, the mice in the drug withdrawal group showed obvious recovery of morphologies of the testis and the kidney, acrosome PAS reaction and mitochondrial ATPase activity.
CONCLUSIONS
Shortterm treatment with gossypol can cause reproductive toxicity and nephrotoxicity in mice, but these toxic effects can be reversed after drug withdrawal.
Topics: Mice; Male; Animals; Gossypol; Testis; Seminiferous Tubules; Spermatids; Spermatogenesis; Adenosine Triphosphatases
PubMed: 36946045
DOI: 10.12122/j.issn.1673-4254.2023.02.13 -
Kidney International Reports Mar 2023Dysregulation of alternative complement pathway underlies the pathogenesis of both C3 glomerulopathy (C3G) and thrombotic microangiopathy (TMA). In this study, we...
INTRODUCTION
Dysregulation of alternative complement pathway underlies the pathogenesis of both C3 glomerulopathy (C3G) and thrombotic microangiopathy (TMA). In this study, we describe both disease entities occurring in 5 patients.
METHODS
We identified 114 patients at our institution from 2007 to 2016 with C3G in native kidney biopsies and those with concurrent TMA were included.
RESULTS
The median age at diagnosis was 58 years (range: 28-69); all were male. Median serum creatinine and proteinuria at presentation were 2.3 mg/dl and 2089 mg/d, respectively. Three cases presented with TMA-predominant phenotype and 2 with C3G-predominant phenotype. Immunofluorescence (IF) showed bright C3 staining in mesangium and/or capillary walls. Electron microscopy showed marked subendothelial expansion by fluffy material in the capillary loops without associated deposits. However, capillary wall deposits were present in other loops in 4 cases. Mesangial deposits were present in all cases. Four cases showed low C3, of which 2 showed low C4. Complement evaluation in 3 cases showed pathogenic CFH mutation in 1 case, and multiple variant of unknown significance along with factor B autoantibody and C4 nephritic factor in 1 case. One patient negative for complement abnormalities had a monoclonal gammopathy. Three cases were treated with steroids and/or immunosuppressants. One case progressed to end-stage renal disease (ESRD) at 38.3 months; the remaining showed median serum creatinine and proteinuria of 2.5 mg/dl and 1169 mg/d, respectively at median follow-up of 17.5 months.
CONCLUSION
Overlap of C3G and TMA is rare and can clinically present as C3G-predominant or TMA-predominant phenotype. The significance of concurrent C3G/TMA findings on long-term renal survival remains to be explored.
PubMed: 36938079
DOI: 10.1016/j.ekir.2022.12.009 -
Frontiers in Medicine 2023Immune complex (IC) vasculitides present inflammations of vessel walls associated with perivascular deposition of immunoglobulins (Igs), mostly ICs. They encompass... (Review)
Review
Immune complex (IC) vasculitides present inflammations of vessel walls associated with perivascular deposition of immunoglobulins (Igs), mostly ICs. They encompass systemic and skin-limited variants of IgA vasculitis (IgAV), cryoglobulinemic vasculitis (CV), rheumatoid, lupus, and hypocomplementemic vasculitides, serum sickness cutaneous IgM/IgG (non-IgA) vasculitis, and recurrent macular (hypergammaglobulinemic or exertion-induced) vasculitis. Serum sickness and CV fulfill the criteria of a type III hypersensitivity immune reaction as large lattices of the IC precipitate at vessel walls and activate polymorphonuclear neutrophils (PMNs). Immunoglobulin-A vasculitis differs with regard to the causes of perivascular deposition of ICs since here many IgA1 molecules are hypoglycosylated (Gd-IgA1), which appears to facilitate their perivascular deposition in skin and mesangium (via e.g. CD71). The reasons for increased generation of immunoglobulins or formation of IC and their perivascular deposition in either skin or systemic organs are different and not fully explored. A common denominator of OC vasculitides is the activation of PMNs near the vessel wall Fcy or Fcα receptors. Acute episodes of IgAV additionally require PMNs to become preactivated by IgA1 or by IC already in circulation. This intravascular priming results in increased adherence and subsequently vessel-destructive NETosis when they encounter IgA deposited at the vessel walls. Binding of IgA1 to PMNs in blood stream is associated with increased serum levels of hypogalactosidated IgA1. The characteristic clinical picture of IgAV (and also of so-called IgG/IgM vasculitis) comprises palpable or retiform purpura with a clear predilection for lower legs, probably due to stasis-related reduction in blood velocity, while in other IC vasculitides, additional factors influence the sites of vasculitides. Our knowledge of distinct forms and different pathophysiological pathways of IC vasculitides may lead to in efficacious or targeted therapies. Antibodies to complement components or intestinal budesonide for IgAV are promising agents (the latter suppresses the pathophysiologically related IgA nephropathy by reducing the generation of mucosal IgA.
PubMed: 36936215
DOI: 10.3389/fmed.2023.1103065