Project description:This study aimed to shed light on the potential pathophysiology of MCD by using glomerular proteomic analysis. Shotgun proteomics using label-free quantitative mass spectrometry was performed on formalin-fixed, paraffin-embedded (FFPE) renal biopsies from two groups of samples: control (CTR) and MCD. Glomeruli were excised from FFPE renal biopsies using laser capture microdissection (LCM), and a single-pot solid-phase-enhanced sample preparation (SP3) digest method was used to improve yield and protein identifications.
Project description:The horseshoe kidney is a frequent urological birth defect. The most frequent complications are urinary tract infections, stones and hydronephrosis. The occurrence of glomerular disease in horseshoe kidney is rare. Therefore, we report the first case of minimal change disease occurring in a patient with horseshoe kidney in literature. A 22-year-old Caucasian man without personal or family medical history admitted to the pneumology department for a pulmonary artery embolism. In presence of a generalized oedema, a biological assessment was performed yielding intense nephrotic syndrome with urine protein excretion 22g/day. The abdominal ultrasound revealed a horseshoe kidney. Hence a scanno-guided kidney biopsy was taken yielding minimal change disease. High dose steroids were started, then gradually tapered with good response. Horseshoe kidney is the most common renal fusion anomaly, with a prevalence of 0.25% among the general population. The occurrence of glomerular nephropathy in horseshoe kidney has been reported in few cases. We report the first case of minimal change disease occurring in a patient with horseshoe kidney in literature. The mechanism of the association between the horseshoe kidney and these renal pathologies could not be explained in the previous reports. There is no literature data indicating a high rate of glomerulonephritis in horseshoe kidneys. The co-incidence of two renal diseases in this patient can be only a coincidence. The question that arises is whether this glomerulopathy is associated or not with this anatomical abnormality. Further studies are needed to answer this question.
Project description:We hypothesized that minimal change disease (MCD) pathogenesis may be associated with mitochondrial injury, and that the degree of mitochondrial injury at the time of diagnosis may serve as a valuable prognostic marker. We compared urinary mitochondrial DNA (mtDNA) at the time of diagnosis in patients with MCD and age- and sex-matched healthy controls (MHC) (n = 10 each). We analyzed the site and signal intensity of immunohistochemical (IHC) staining of stimulator of interferon genes (STING) using kidney tissues at the time of diagnosis in patients with MCD. Patients with MCD were divided into high (n = 6) and low-intensity (n = 14) subgroups according to the signal intensity. Urinary mtDNA levels were elevated in the MCD groups more than in the MHC group (p < 0.001). Time-averaged proteinuria and frequency of relapses during the follow-up period were higher in the high-intensity than in the low-intensity subgroup (1.18 ± 0.54 vs. 0.57 ± 0.45 g/day, p = 0.022; and 0.72 ± 0.60 vs. 0.09 ± 0.22 episodes/year, p = 0.022, respectively). Mitochondrial injury may be associated with MCD pathogenesis, and the signal intensity of STING IHC staining at the time of diagnosis could be used as a valuable prognostic marker in MCD.
Project description:IntroductionMinimal change disease (MCD) is considered a podocyte disorder triggered by unknown circulating factors. Here, we hypothesized that the endothelial cell (EC) is also involved in MCD.MethodsWe studied 45 children with idiopathic nephrotic syndrome (44 had steroid sensitive nephrotic syndrome [SSNS], and 12 had biopsy-proven MCD), 21 adults with MCD, and 38 healthy controls (30 children, 8 adults). In circulation, we measured products of endothelial glycocalyx (EG) degradation (syndecan-1, heparan sulfate [HS] fragments), HS proteoglycan cleaving enzymes (matrix metalloprotease-2 [MMP-2], heparanase activity), and markers of endothelial activation (von Willebrand factor [vWF], thrombomodulin) by enzyme-linked immunosorbent assay (ELISA) and mass spectrometry. In human kidney tissue, we assessed glomerular EC (GEnC) activation by immunofluorescence of caveolin-1 (n = 11 MCD, n = 5 controls). In vitro, we cultured immortalized human GEnC with sera from control subjects and patients with MCD/SSNS sera in relapse (n = 5 per group) and performed Western blotting of thrombomodulin of cell lysates as surrogate marker of endothelial activation.ResultsIn circulation, median concentrations of all endothelial markers were higher in patients with active disease compared with controls and remained high in some patients during remission. In the MCD glomerulus, caveolin-1 expression was higher, in an endothelial-specific pattern, compared with controls. In cultured human GEnC, sera from children with MCD/SSNS in relapse increased thrombomodulin expression compared with control sera.ConclusionOur data show that alterations involving the systemic and glomerular endothelium are nearly universal in patients with MCD and SSNS, and that GEnC can be directly activated by circulating factors present in the MCD/SSNS sera during relapse.
Project description:BackgroundMinimal Change Disease (MCD) is the most common type of nephrotic syndrome in children. Angiopoietin-like-4 (Angplt4) has been proposed as mediator of proteinuria in MCD. The aim of this study was to evaluate the role of Angptl4 as a biomarker in MCD.MethodsPatients with biopsy-proven primary MCD, focal segmental glomerulosclerosis, membranous nephropathy (60, 52 and 52 respectively) and 18 control subjects had urinary and serum Angptl4 measured by Elisa. Frozen kidney tissue sections were stained for Angptl4.ResultsAngptl4 was not identified in glomeruli of MCD patients in relapse. Urinary Angptl4 levels were elevated in MCD in relapse as well as in patients with massive proteinuria due to other glomerular diseases.ConclusionNeither serum nor urine Angptl4 appear to be good biomarkers in MCD. Elevated urinary Angptl4 n glomerular disease appears to reflect the degree of proteinuria rather than any specific disease.
Project description:Introduction: Minimal change disease (MCD) is a major cause of nephrotic syndrome. With a substantial number of patients requiring long-term immunosuppression leading to significant morbidity, the study aim was to determine MCD glomerular transcriptome to serve as a basis for biomarker discovery and novel drug target identification. Animal work showed podocyte injury induced by IL-7/IL-7R signaling (Zhai S, BBRC, 2018). Methods: Renal biopsies from adult patients representing the following groups were selected from the Norwegian Kidney Biopsy Registry: MCD (n=14), as well as normal tissue (n=8) and primary membranous nephropathy (MN; n=12) as the two reference groups. RNA for 75 base-pair paired-end RNASeq was obtained by dissecting glomeruli via laser capture microdissection (LCM) from FFPE cross-sections. Systematic delineation of condition-specific alteration in transcriptional landscapes was achieved by combining pathway-centered analyses with methodologies derived from network science and integrating multiple bioinformatics resources. Results: Compared to normal glomeruli, glomeuli from MCD displayed an inflammatory signature that appeared to be predominantly governed by the IL1 and IL7 systems. While enrichment of IL1 production and secretion was a shared feature of MCD and MN compared to normal tissue, responses involving IL7 pathway activation were unique to MCD. Indeed, IL7R expressed by glomeruli was the most up-regulated gene of to the interleukin-family in MCD vs normal controls. IL7 pathway activation was paralleled by significant enrichment in adaptive immune system processes and transcriptional regulation and depletion in pathways related to energy metabolism and transcription. Downregulation of these organ function-related themes again occurred predominately in MDC and were significantly less pronounced in MN. Conclusion: Our results demonstrate that archival FFPE-biopsies can be used to generate glomeruli-specific gene expression profiles suitable for systematic delineation of kidney-associated diseases. Here the latter provides a data-driven rationale to experimentally address these MCD-specific features as biomarkers and as novel drug targets. In this context inhibiting activation of the IL7 pathway may be particularly promising.
Project description:The mechanism underlying podocyte dysfunction in minimal change disease (MCD) remains unknown. This study aimed to shed light on the potential pathophysiology of MCD using glomerular proteomic analysis. Shotgun proteomics using label-free quantitative mass spectrometry was performed on formalin-fixed, paraffin-embedded (FFPE) renal biopsies from two groups of samples: control (CTR) and MCD. Glomeruli were excised from FFPE renal biopsies using laser capture microdissection (LCM), and a single-pot solid-phase-enhanced sample preparation (SP3) digestion method was used to improve yield and protein identifications. Principal component analysis (PCA) revealed a distinct separation between the CTR and MCD groups. Forty-eight proteins with different abundance between the two groups (p-value ≤ 0.05 and |FC| ≥ 1.5) were identified. These may represent differences in podocyte structure, as well as changes in endothelial or mesangial cells and extracellular matrix, and some were indeed found in several of these structures. However, most differentially expressed proteins were linked to the podocyte cytoskeleton and its dynamics. Some of these proteins are known to be involved in focal adhesion (NID1 and ITGA3) or slit diaphragm signaling (ANXA2, TJP1 and MYO1C), while others are structural components of the actin and microtubule cytoskeleton of podocytes (ACTR3 and NES). This study suggests the potential of mass spectrometry-based shotgun proteomic analysis with LCM glomeruli to yield valuable insights into the pathogenesis of podocytopathies like MCD. The most significantly dysregulated proteins in MCD could be attributable to cytoskeleton dysfunction or may be a compensatory response to cytoskeleton malfunction caused by various triggers.
Project description:The most frequently described glomerulopathy in patients with thymoma is minimal change disease (MCD). The present study reports the case of a 63-year-old female with recurrent thymoma and poorly-controlled paraneoplastic MCD, who was enrolled on a phase I/II clinical trial (no. NCT01100944) and treated with the histone deacetylase inhibitor, belinostat, in combination with cisplatin, doxorubicin and cyclophosphamide. Treatment resulted in a complete radiological response, a dramatic reduction in proteinuria and changes in immune cell subset composition, consisting of a reduction in the number of T helper (Th)1, Th2, Th17 and regulatory T cells. Changes in T-cell polarization were also observed with an increase in the Th1/Th2 ratio. To the best of our knowledge, the current study is the first to provide a detailed description of changes in immune cell subset composition in thymoma-associated MCD. Early administration of effective antitumor therapy should be considered in these cases, particularly when proteinuria is poorly controlled despite the use of steroids and other immunosuppressive therapies.
Project description:Background: IgA nephropathy (IgAN) has a high degree of heterogeneity in clinical and pathological features. Among all subsets of IgAN, the pathogenesis of IgAN with minimal change disease (MCD-IgAN) remained controversial. Methods: We analyzed the clinical and pathological characteristics of MCD-IgAN patients in a retrospective cohort. Patients diagnosed with IgAN, excluding MCD-IgAN, were randomly selected as controls. Levels of plasma galactose-deficient IgA1 (GdIgA1), IgG autoantibodies against GdIgA1, GdIgA1 deposition in the glomerulus, and inflammatory reactivity of circulating poly-IgA1 complexes to cultured mesangial cells were evaluated. Results: Patients with MCD-IgAN had significantly higher levels of proteinuria and estimated glomerular filtration rate (eGFR), lower levels of albumin and urine blood cells, and milder histological lesions by a light microscope compared to IgAN patients, which bears a resemblance to MCD. Lower levels of GdIgA1 (3.41 ± 1.68 vs. 4.92 ± 2.30 μg/ml, p = 0.009) and IgG antiglycan autoantibodies (23.25 ± 22.59 vs. 76.58 ± 71.22 IU/ml, p < 0.001) were found in MCD-IgAN patients than those in IgAN controls. Meanwhile, weaker fluorescence intensities of both IgA and GdIgA1 were observed in the glomerulus of MCD-IgAN patients compared to those in IgAN patients. Furthermore, poly-IgA1 complexes from MCD-IgAN patients induced weaker inflammatory effects on cultured mesangial cells than those from IgAN patients in vitro. Conclusion: The results demonstrated that MCD-IgAN cases represent a dual glomerulopathy, namely, mild IgAN with superimposed MCD, which furthermore provides substantial evidence for the corticosteroids therapy in MCD-IgAN patients as the guidelines recommended.