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Delaney M, Zhao Y, van de Leemput J, Lee H, Han Z. Actin Cytoskeleton and Integrin Components Are Interdependent for Slit Diaphragm Maintenance in Drosophila Nephrocytes. Cells 2024; 13:1350. [PMID: 39195240 DOI: 10.3390/cells13161350] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2024] [Revised: 08/08/2024] [Accepted: 08/11/2024] [Indexed: 08/29/2024] Open
Abstract
In nephrotic syndrome, the podocyte filtration structures are damaged in a process called foot process effacement. This is mediated by the actin cytoskeleton; however, which actins are involved and how they interact with other filtration components, like the basement membrane, remains poorly understood. Here, we used the well-established Drosophila pericardial nephrocyte-the equivalent of podocytes in flies-knockdown models (RNAi) to study the interplay of the actin cytoskeleton (Act5C, Act57B, Act42A, and Act87E), alpha- and beta-integrin (basement membrane), and the slit diaphragm (Sns and Pyd). Knockdown of an actin gene led to variations of formation of actin stress fibers, the internalization of Sns, and a disrupted slit diaphragm cortical pattern. Notably, deficiency of Act5C, which resulted in complete absence of nephrocytes, could be partially mitigated by overexpressing Act42A or Act87E, suggesting at least partial functional redundancy. Integrin localized near the actin cytoskeleton as well as slit diaphragm components, but when the nephrocyte cytoskeleton or slit diaphragm was disrupted, this switched to colocalization, both at the surface and internalized in aggregates. Altogether, the data show that the interdependence of the slit diaphragm, actin cytoskeleton, and integrins is key to the structure and function of the Drosophila nephrocyte.
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Affiliation(s)
- Megan Delaney
- Center for Precision Disease Modeling, Department of Medicine, University of Maryland School of Medicine, 670 West Baltimore Street, Baltimore, MD 21201, USA
- Division of Endocrinology, Diabetes and Nutrition, Department of Medicine, University of Maryland School of Medicine, 670 West Baltimore Street, Baltimore, MD 21201, USA
| | - Yunpo Zhao
- Center for Precision Disease Modeling, Department of Medicine, University of Maryland School of Medicine, 670 West Baltimore Street, Baltimore, MD 21201, USA
- Division of Endocrinology, Diabetes and Nutrition, Department of Medicine, University of Maryland School of Medicine, 670 West Baltimore Street, Baltimore, MD 21201, USA
| | - Joyce van de Leemput
- Center for Precision Disease Modeling, Department of Medicine, University of Maryland School of Medicine, 670 West Baltimore Street, Baltimore, MD 21201, USA
- Division of Endocrinology, Diabetes and Nutrition, Department of Medicine, University of Maryland School of Medicine, 670 West Baltimore Street, Baltimore, MD 21201, USA
| | - Hangnoh Lee
- Center for Precision Disease Modeling, Department of Medicine, University of Maryland School of Medicine, 670 West Baltimore Street, Baltimore, MD 21201, USA
- Division of Endocrinology, Diabetes and Nutrition, Department of Medicine, University of Maryland School of Medicine, 670 West Baltimore Street, Baltimore, MD 21201, USA
| | - Zhe Han
- Center for Precision Disease Modeling, Department of Medicine, University of Maryland School of Medicine, 670 West Baltimore Street, Baltimore, MD 21201, USA
- Division of Endocrinology, Diabetes and Nutrition, Department of Medicine, University of Maryland School of Medicine, 670 West Baltimore Street, Baltimore, MD 21201, USA
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2
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Laudon A, Wang Z, Zou A, Sharma R, Ji J, Kim C, Qian Y, Ye Q, Chen H, Henderson JM, Zhang C, Kolachalama VB, Lu W. Digital pathology assessment of kidney glomerular filtration barrier ultrastructure in an animal model of podocytopathy. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.06.14.599097. [PMID: 38948787 PMCID: PMC11212870 DOI: 10.1101/2024.06.14.599097] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/02/2024]
Abstract
Background Transmission electron microscopy (TEM) images can visualize kidney glomerular filtration barrier ultrastructure, including the glomerular basement membrane (GBM) and podocyte foot processes (PFP). Podocytopathy is associated with glomerular filtration barrier morphological changes observed experimentally and clinically by measuring GBM or PFP width. However, these measurements are currently performed manually. This limits research on podocytopathy disease mechanisms and therapeutics due to labor intensiveness and inter-operator variability. Methods We developed a deep learning-based digital pathology computational method to measure GBM and PFP width in TEM images from the kidneys of Integrin-Linked Kinase (ILK) podocyte-specific conditional knockout (cKO) mouse, an animal model of podocytopathy, compared to wild-type (WT) control mouse. We obtained TEM images from WT and ILK cKO littermate mice at 4 weeks old. Our automated method was composed of two stages: a U-Net model for GBM segmentation, followed by an image processing algorithm for GBM and PFP width measurement. We evaluated its performance with a 4-fold cross-validation study on WT and ILK cKO mouse kidney pairs. Results Mean (95% confidence interval) GBM segmentation accuracy, calculated as Jaccard index, was 0.73 (0.70-0.76) for WT and 0.85 (0.83-0.87) for ILK cKO TEM images. Automated and manual GBM width measurements were similar for both WT (p=0.49) and ILK cKO (p=0.06) specimens. While automated and manual PFP width measurements were similar for WT (p=0.89), they differed for ILK cKO (p<0.05) specimens. WT and ILK cKO specimens were morphologically distinguishable by manual GBM (p<0.05) and PFP (p<0.05) width measurements. This phenotypic difference was reflected in the automated GBM (p<0.05) more than PFP (p=0.06) widths. Conclusions These results suggest that certain automated measurements enabled via deep learning-based digital pathology tools could distinguish healthy kidneys from those with podocytopathy. Our proposed method provides high-throughput, objective morphological analysis and could facilitate podocytopathy research and translate into clinical diagnosis.
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Affiliation(s)
- Aksel Laudon
- Department of Biomedical Engineering, Boston University, Boston, MA, USA
- Nephrology Section, Department of Medicine, Boston University Chobanian & Avedisian School of Medicine, Boston Medical Center, Boston, MA, USA
| | - Zhaoze Wang
- Department of Biomedical Engineering, Boston University, Boston, MA, USA
| | - Anqi Zou
- Computational Biomedicine Section, Department of Medicine, Boston University Chobanian & Avedisian School of Medicine, Boston Medical Center, Boston, MA, USA
| | - Richa Sharma
- Nephrology Section, Department of Medicine, Boston University Chobanian & Avedisian School of Medicine, Boston Medical Center, Boston, MA, USA
| | - Jiayi Ji
- Nephrology Section, Department of Medicine, Boston University Chobanian & Avedisian School of Medicine, Boston Medical Center, Boston, MA, USA
| | - Connor Kim
- Department of Biomedical Engineering, Boston University, Boston, MA, USA
| | - Yingzhe Qian
- Department of Biomedical Engineering, Boston University, Boston, MA, USA
| | - Qin Ye
- Department of Biomedical Engineering, Boston University, Boston, MA, USA
| | - Hui Chen
- Department of Pathology and Laboratory Medicine, Boston University Chobanian & Avedisian School of Medicine, Boston Medical Center, Boston, MA, USA
| | - Joel M Henderson
- Department of Pathology and Laboratory Medicine, Boston University Chobanian & Avedisian School of Medicine, Boston Medical Center, Boston, MA, USA
| | - Chao Zhang
- Computational Biomedicine Section, Department of Medicine, Boston University Chobanian & Avedisian School of Medicine, Boston Medical Center, Boston, MA, USA
| | - Vijaya B Kolachalama
- Computational Biomedicine Section, Department of Medicine, Boston University Chobanian & Avedisian School of Medicine, Boston Medical Center, Boston, MA, USA
- Department of Computer Science and Faculty of Computing & Data Sciences, Boston University, Boston, MA, USA
| | - Weining Lu
- Nephrology Section, Department of Medicine, Boston University Chobanian & Avedisian School of Medicine, Boston Medical Center, Boston, MA, USA
- Department of Pathology and Laboratory Medicine, Boston University Chobanian & Avedisian School of Medicine, Boston Medical Center, Boston, MA, USA
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3
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Zhou Y, Hou S, Huang XY, Chang DY, Wang H, Nie L, Xiong ZY, Chen M, Zhao MH, Wang SX. Association of podocyte ultrastructural changes with proteinuria and pathological classification in type 2 diabetic nephropathy. DIABETES & METABOLISM 2024; 50:101547. [PMID: 38852840 DOI: 10.1016/j.diabet.2024.101547] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/13/2024] [Revised: 06/02/2024] [Accepted: 06/02/2024] [Indexed: 06/11/2024]
Abstract
AIMS Podocyte injury plays an essential role in the progression of diabetic nephropathy (DN). The associations between the ultrastructural changes of podocyte with proteinuria and the pathological classification of DN proposed by Renal Pathology Society (RPS) have not been clarified in patients with type 2 diabetic nephropathy (T2DN). METHODS We collected 110 patients with kidney biopsy-confirmed T2DN at Peking University First Hospital from 2017 to 2022. The morphometric analysis on the podocyte foot process width (FPW) and podocyte detachment (PD) as markers of podocyte injury was performed, and the correlations between the ultrastructural changes of podocytes with severity of proteinuria and the RPS pathological classification of DN were analyzed. RESULTS Mean FPW was significantly broader in the group of T2DN patients with nephrotic proteinuria (565.1 nm) than those with microalbuminuria (437.4 nm) or overt proteinuria (494.6 nm). The cut-off value of FPW (> 506 nm) could differentiate nephrotic proteinuria from non-nephrotic proteinuria with a sensitivity of 75.3% and a specificity of 75.8%. Percentage of PD was significantly higher in group of nephrotic proteinuria (3.2%) than that in microalbuminuria (0%) or overt proteinuria (0.2%). FPW and PD significantly correlated with proteinuria in T2DN (r = 0.473, p < 0.001 and r = 0.656, P < 0.001). FPW and PD correlated with RPS pathological classification of T2DN (r = 0.179, P = 0.014 and r = 0.250, P = 0.001). FPW value was increased significantly with more severe DN classification (P for trend =0.007). The percentage of PD tended to increase with more severe DN classification (P for trend = 0.017). CONCLUSIONS Podocyte injury, characterized by FPW broadening and PD, was associated with the severity of proteinuria and the pathological classification of DN.
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Affiliation(s)
- Yue Zhou
- Division of Nephrology, Peking University First Hospital, Beijing, 100034, PR China; Division of Nephrology, Peking University Shenzhen Hospital, Shenzhen, 518000, PR China
| | - Shuang Hou
- Division of Nephrology, Peking University Shenzhen Hospital, Shenzhen, 518000, PR China
| | - Xiao-Yan Huang
- Division of Nephrology, Peking University Shenzhen Hospital, Shenzhen, 518000, PR China
| | - Dong-Yuan Chang
- Division of Nephrology, Peking University First Hospital, Beijing, 100034, PR China
| | - Hui Wang
- Division of Nephrology, Peking University First Hospital, Beijing, 100034, PR China; Laboratory of Electron Microscopy, Pathological Center, Peking University First Hospital, Beijing, 100034, PR China
| | - Lin Nie
- Division of Nephrology, Peking University First Hospital, Beijing, 100034, PR China; Laboratory of Electron Microscopy, Pathological Center, Peking University First Hospital, Beijing, 100034, PR China
| | - Zu-Ying Xiong
- Division of Nephrology, Peking University Shenzhen Hospital, Shenzhen, 518000, PR China
| | - Min Chen
- Division of Nephrology, Peking University First Hospital, Beijing, 100034, PR China
| | - Ming-Hui Zhao
- Division of Nephrology, Peking University First Hospital, Beijing, 100034, PR China
| | - Su-Xia Wang
- Division of Nephrology, Peking University First Hospital, Beijing, 100034, PR China; Laboratory of Electron Microscopy, Pathological Center, Peking University First Hospital, Beijing, 100034, PR China.
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4
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Finn LS. Nephrotic Syndrome Throughout Childhood: Diagnosing Podocytopathies From the Womb to the Dorm. Pediatr Dev Pathol 2024:10935266241242669. [PMID: 38745407 DOI: 10.1177/10935266241242669] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 05/16/2024]
Abstract
The etiologies of podocyte dysfunction that lead to pediatric nephrotic syndrome (NS) are vast and vary with age at presentation. The discovery of numerous novel genetic podocytopathies and the evolution of diagnostic technologies has transformed the investigation of steroid-resistant NS while simultaneously promoting the replacement of traditional morphology-based disease classifications with a mechanistic approach. Podocytopathies associated with primary and secondary steroid-resistant NS manifest as diffuse mesangial sclerosis, minimal change disease, focal segmental glomerulosclerosis, and collapsing glomerulopathy. Molecular testing, once an ancillary option, has become a vital component of the clinical investigation and when paired with kidney biopsy findings, provides data that can optimize treatment and prognosis. This review focuses on the causes including selected monogenic defects, clinical phenotypes, histopathologic findings, and age-appropriate differential diagnoses of nephrotic syndrome in the pediatric population with an emphasis on podocytopathies.
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Affiliation(s)
- Laura S Finn
- Department of Pathology and Laboratory Medicine, Perelman School of Medicine at The University of Pennsylvania, The Children's Hospital of Philadelphia, Philadelphia, PA, USA
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5
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Mirioglu S, Daniel-Fischer L, Berke I, Ahmad SH, Bajema IM, Bruchfeld A, Fernandez-Juarez GM, Floege J, Frangou E, Goumenos D, Griffith M, Moran SM, van Kooten C, Steiger S, Stevens KI, Turkmen K, Willcocks LC, Kronbichler A. Management of adult patients with podocytopathies: an update from the ERA Immunonephrology Working Group. Nephrol Dial Transplant 2024; 39:569-580. [PMID: 38341276 PMCID: PMC11024823 DOI: 10.1093/ndt/gfae025] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2023] [Indexed: 02/12/2024] Open
Abstract
The histopathological lesions, minimal change disease (MCD) and focal segmental glomerulosclerosis (FSGS) are entities without immune complex deposits which can cause podocyte injury, thus are frequently grouped under the umbrella of podocytopathies. Whether MCD and FSGS may represent a spectrum of the same disease remains a matter of conjecture. Both frequently require repeated high-dose glucocorticoid therapy with alternative immunosuppressive treatments reserved for relapsing or resistant cases and response rates are variable. There is an unmet need to identify patients who should receive immunosuppressive therapies as opposed to those who would benefit from supportive strategies. Therapeutic trials focusing on MCD are scarce, and the evidence used for the 2021 Kidney Disease: Improving Global Outcomes (KDIGO) guideline for the management of glomerular diseases largely stems from observational and pediatric trials. In FSGS, the differentiation between primary forms and those with underlying genetic variants or secondary forms further complicates trial design. This article provides a perspective of the Immunonephrology Working Group (IWG) of the European Renal Association (ERA) and discusses the KDIGO 2021 Clinical Practice Guideline for the Management of Glomerular Diseases focusing on the management of MCD and primary forms of FSGS in the context of recently published evidence, with a special emphasis on the role of rituximab, cyclophosphamide, supportive treatment options and ongoing clinical trials in the field.
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Affiliation(s)
- Safak Mirioglu
- Division of Nephrology, Bezmialem Vakif University School of Medicine, Istanbul, Turkey
- Department of Immunology, Aziz Sancar Institute of Experimental Medicine, Istanbul University, Istanbul, Turkey
| | - Lisa Daniel-Fischer
- Division of Pediatric Nephrology and Gastroenterology, Department of Pediatrics and Adolescent Medicine, Comprehensive Center for Pediatrics, Medical University of Vienna, Vienna, Austria
| | - Ilay Berke
- Division of Nephrology, Marmara University School of Medicine, Istanbul, Turkey
| | - Syed Hasan Ahmad
- Department of Renal Medicine, Addenbrooke's Hospital, Cambridge University Hospitals, Cambridge, UK
| | - Ingeborg M Bajema
- Department of Pathology and Medical Biology, University of Groningen, University Medical Center Groningen, The Netherlands
| | - Annette Bruchfeld
- Department of Health, Medicine and Caring Sciences, Linköping University, Linköping, Sweden
- Department of Renal Medicine, Karolinska University Hospital and CLINTEC Karolinska Institutet, Stockholm, Sweden
| | | | - Jürgen Floege
- Division of Nephrology, RWTH Aachen University Hospital, Aachen, Germany
| | - Eleni Frangou
- Department of Nephrology, Limassol General Hospital, Limassol, Cyprus; University of Nicosia Medical School, Nicosia, Cyprus
| | - Dimitrios Goumenos
- Department of Nephrology and Renal Transplantation, Patras University Hospital, Patras, Greece
| | - Megan Griffith
- Imperial College Healthcare NHS Trust Renal and Transplant Centre, Hammersmith Hospital, London, United Kingdom
| | - Sarah M Moran
- Cork University Hospital, University College Cork, Cork, Ireland
| | - Cees van Kooten
- Division of Nephrology and Transplant Medicine, Department of Medicine, Leiden University Medical Center, Leiden, The Netherlands
| | - Stefanie Steiger
- Division of Nephrology, Department of Internal Medicine IV, Hospital of the Ludwig-Maximilians-University, Munich, Germany
| | - Kate I Stevens
- Glasgow Renal and Transplant Unit, Queen Elizabeth University Hospital, Glasgow, UK
| | - Kultigin Turkmen
- Division of Nephrology, Department of Internal Medicine, Necmettin Erbakan University, Konya, Turkey
| | - Lisa C Willcocks
- Department of Renal Medicine, Addenbrooke's Hospital, Cambridge University Hospitals, Cambridge, UK
| | - Andreas Kronbichler
- Department of Internal Medicine IV, Nephrology and Hypertension, Medical University Innsbruck, Innsbruck, Austria
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6
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Hua W, Peng L, Chen XM, Jiang X, Hu J, Jiang XH, Xiang X, Wan J, Long Y, Xiong J, Ma X, Du X. CD36-mediated podocyte lipotoxicity promotes foot process effacement. Open Med (Wars) 2024; 19:20240918. [PMID: 38584832 PMCID: PMC10996993 DOI: 10.1515/med-2024-0918] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2023] [Revised: 02/07/2024] [Accepted: 02/09/2024] [Indexed: 04/09/2024] Open
Abstract
Background Lipid metabolism disorders lead to lipotoxicity. The hyperlipidemia-induced early stage of renal injury mainly manifests as podocyte damage. CD36 mediates fatty acid uptake and the subsequent accumulation of toxic lipid metabolites, resulting in podocyte lipotoxicity. Methods Male Sprague-Dawley rats were divided into two groups: the normal control group and the high-fat diet group (HFD). Podocytes were cultured and treated with palmitic acid (PA) and sulfo-N-succinimidyl oleate (SSO). Protein expression was measured by immunofluorescence and western blot analysis. Boron-dipyrromethene staining and Oil Red O staining was used to analyze fatty acid accumulation. Results Podocyte foot process (FP) effacement and marked proteinuria occurred in the HFD group. CD36 protein expression was upregulated in the HFD group and in PA-treated podocytes. PA-treated podocytes showed increased fatty acid accumulation, reactive oxygen species (ROS) production, and actin cytoskeleton rearrangement. However, pretreatment with the CD36 inhibitor SSO decreased lipid accumulation and ROS production and alleviated actin cytoskeleton rearrangement in podocytes. The antioxidant N-acetylcysteine suppressed PA-induced podocyte FP effacement and ROS generation. Conclusions CD36 participated in fatty acid-induced FP effacement in podocytes via oxidative stress, and CD36 inhibitors may be helpful for early treatment of kidney injury.
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Affiliation(s)
- Wei Hua
- Department of Nephrology, The First Affiliated Hospital of Chongqing Medical and Pharmaceutical College, Chongqing400000, China
| | - Lan Peng
- Basic Department, Chongqing Medical and Pharmaceutical College, Chongqing401331, China
| | - Xue-mei Chen
- Emergency Department, The First Affiliated Hospital of Chongqing Medical University, Chongqing400042, China
| | - XuShun Jiang
- Department of Nephrology, The First Affiliated Hospital of Chongqing Medical University, Chongqing400042, China
| | - JianGuo Hu
- Department of Obstetrics and Gynecology, Second Affiliated Hospital, Chongqing Medical University, Chongqing, China
| | - Xian-Hong Jiang
- Department of Nephrology, The First Affiliated Hospital of Chongqing Medical and Pharmaceutical College, Chongqing400000, China
| | - Xu Xiang
- Department of Nephrology, The First Affiliated Hospital of Chongqing Medical and Pharmaceutical College, Chongqing400000, China
| | - Jiangmin Wan
- Department of Nephrology, People’s Hospital of Qijiang District, Chongqing401420, China
| | - Yingfei Long
- Department of Obstetrics and Gynecology, The Third Affiliated Hospital of Chongqing Medical University, Chongqing, 401120, China
| | | | - Xueyi Ma
- Department of Nephrology, The First Affiliated Hospital of Chongqing Medical and Pharmaceutical College, Chongqing400000, China
| | - Xiaogang Du
- Department of Nephrology, The First Affiliated Hospital of Chongqing Medical University, Youyi Road 1, Chongqing 400042, China
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7
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Shirai Y, Miura K, Ishizuka K, Ando T, Kanda S, Hashimoto J, Hamasaki Y, Hotta K, Ito N, Honda K, Tanabe K, Takano T, Hattori M. A multi-institutional study found a possible role of anti-nephrin antibodies in post-transplant focal segmental glomerulosclerosis recurrence. Kidney Int 2024; 105:608-617. [PMID: 38110152 DOI: 10.1016/j.kint.2023.11.022] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2023] [Revised: 11/07/2023] [Accepted: 11/10/2023] [Indexed: 12/20/2023]
Abstract
Possible roles of anti-nephrin antibodies in post-transplant recurrent focal segmental glomerulosclerosis (FSGS) have been reported recently. To confirm these preliminary results, we performed a multi-institutional study of 22 Japanese pediatric kidney transplant recipients with FSGS including eight genetic FSGS and 14 non-genetic (presumed primary) FSGS. Eleven of the 14 non-genetic FSGS patients had post-transplant recurrent FSGS. Median (interquartile range) plasma levels of anti-nephrin antibodies in post-transplant recurrent FSGS measured using ELISA were markedly high at 899 (831, 1292) U/mL (cutoff 231 U/mL) before transplantation or during recurrence. Graft biopsies during recurrence showed punctate IgG deposition co-localized with nephrin that had altered localization with increased nephrin tyrosine phosphorylation and Src homology and collagen homology A expressions. Graft biopsies after remission showed no signals for IgG and a normal expression pattern of nephrin. Anti-nephrin antibody levels decreased to 155 (53, 367) U/mL in five patients with samples available after remission. In patients with genetic FSGS as in those with non-genetic FSGS without recurrence, anti-nephrin antibody levels were comparable to those of 30 control individuals, and graft biopsies had no signals for IgG and a normal expression pattern of nephrin. Thus, our results suggest that circulating anti-nephrin antibodies are a possible candidate for circulating factors involved in the pathogenesis of post-transplant recurrent FSGS and that this may be mediated by nephrin phosphorylation. Larger studies including other ethnicities are required to confirm this finding.
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Affiliation(s)
- Yoko Shirai
- Department of Pediatric Nephrology, Tokyo Women's Medical University, Tokyo, Japan
| | - Kenichiro Miura
- Department of Pediatric Nephrology, Tokyo Women's Medical University, Tokyo, Japan
| | - Kiyonobu Ishizuka
- Department of Pediatric Nephrology, Tokyo Women's Medical University, Tokyo, Japan
| | - Taro Ando
- Department of Pediatric Nephrology, Tokyo Women's Medical University, Tokyo, Japan
| | | | - Junya Hashimoto
- Department of Nephrology, Toho University Faculty of Medicine, Tokyo, Japan
| | - Yuko Hamasaki
- Department of Nephrology, Toho University Faculty of Medicine, Tokyo, Japan
| | - Kiyohiko Hotta
- Department of Urology, Hokkaido University, Graduate School of Medicine, Hokkaido, Japan
| | - Naoko Ito
- Department of Surgical Pathology, Tokyo Women's Medical University, Tokyo, Japan
| | - Kazuho Honda
- Department of Anatomy, Showa University School of Medicine, Tokyo, Japan
| | - Kenji Tanabe
- Medical Research Institute, Tokyo Women's Medical University, Tokyo, Japan
| | - Tomoko Takano
- Division of Nephrology, McGill University Health Centre, Montreal, Québec, Canada
| | - Motoshi Hattori
- Department of Pediatric Nephrology, Tokyo Women's Medical University, Tokyo, Japan.
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Smerkous D, Mauer M, Tøndel C, Svarstad E, Gubler MC, Nelson RG, Oliveira JP, Sargolzaeiaval F, Najafian B. Development of an automated estimation of foot process width using deep learning in kidney biopsies from patients with Fabry, minimal change, and diabetic kidney diseases. Kidney Int 2024; 105:165-176. [PMID: 37774924 PMCID: PMC10842003 DOI: 10.1016/j.kint.2023.09.011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2022] [Revised: 09/06/2023] [Accepted: 09/15/2023] [Indexed: 10/01/2023]
Abstract
Podocyte injury plays a key role in pathogenesis of many kidney diseases with increased podocyte foot process width (FPW), an important measure of podocyte injury. Unfortunately, there is no consensus on the best way to estimate FPW and unbiased stereology, the current gold standard, is time consuming and not widely available. To address this, we developed an automated FPW estimation technique using deep learning. A U-Net architecture variant model was trained to semantically segment the podocyte-glomerular basement membrane interface and filtration slits. Additionally, we employed a post-processing computer vision approach to accurately estimate FPW. A custom segmentation utility was also created to manually classify these structures on digital electron microscopy (EM) images and to prepare a training dataset. The model was applied to EM images of kidney biopsies from 56 patients with Fabry disease, 15 with type 2 diabetes, 10 with minimal change disease, and 17 normal individuals. The results were compared with unbiased stereology measurements performed by expert technicians unaware of the clinical information. FPW measured by deep learning and by the expert technicians were highly correlated and not statistically different in any of the studied groups. A Bland-Altman plot confirmed interchangeability of the methods. FPW measurement time per biopsy was substantially reduced by deep learning. Thus, we have developed a novel validated deep learning model for FPW measurement on EM images. The model is accessible through a cloud-based application making calculation of this important biomarker more widely accessible for research and clinical applications.
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Affiliation(s)
- David Smerkous
- Department of Laboratory Medicine and Pathology, University of Washington, Seattle, Washington, USA; Paul G. Allen School of Computer Science and Engineering, University of Washington, Seattle, Washington, USA
| | - Michael Mauer
- Department of Pediatrics, University of Minnesota, Minneapolis, Minnesota, USA; Department of Medicine, University of Minnesota, Minneapolis, Minnesota, USA
| | - Camilla Tøndel
- Department of Pediatrics, Haukeland University Hospital, Bergen, Norway; Institute of Clinical Medicine, University of Bergen, Bergen, Norway
| | - Einar Svarstad
- Department of Clinical Medicine, University of Bergen, Bergen, Norway
| | - Marie-Claire Gubler
- INSERM U1163, Imagine Institute, Necker-Enfants Malades Hospital, Paris, France
| | - Robert G Nelson
- Chronic Kidney Disease Section, Phoenix Epidemiology and Clinical Research Branch, National Institute of Diabetes and Digestive and Kidney Diseases, Phoenix, Arizona, USA
| | - João-Paulo Oliveira
- Service of Medical Genetics, São João University Hospital; Department of Medical Genetics, Faculty of Medicine and i3S-Institute for Research and Innovation in Health, University of Porto, Porto, Portugal
| | - Forough Sargolzaeiaval
- Department of Laboratory Medicine and Pathology, University of Washington, Seattle, Washington, USA
| | - Behzad Najafian
- Department of Laboratory Medicine and Pathology, University of Washington, Seattle, Washington, USA.
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9
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Troyanov S, Jauhal A, Reich HN, Hladunewich MA, Cattran DC. Focal Segmental Glomerulosclerosis: Assessing the Risk of Relapse. Kidney Int Rep 2023; 8:2403-2415. [PMID: 38025232 PMCID: PMC10658237 DOI: 10.1016/j.ekir.2023.08.035] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2023] [Revised: 08/18/2023] [Accepted: 08/28/2023] [Indexed: 12/01/2023] Open
Abstract
Introduction Kidney outcomes are improved in primary focal segmental glomerulosclerosis (FSGS) by maintaining a remission in proteinuria. However, characteristics associated with relapses are uncertain. We sought to identify these by analyzing each remission. Methods We performed a retrospective study in patients with biopsy-proven lesions of FSGS, absent identifiable secondary cause, who had at least 1 remission from nephrotic-range proteinuria. In each patient, we identified every remission, every relapse, and their durations. Using a multilevel logistic regression to account for the clustering of multiple remissions within a patient, we tested which clinical characteristics were independently associated with relapses. Results In 203 individuals, 312 remissions occurred, 177 with and 135 without relapse. A minority of remissions were atypical, defined by either absent hypoalbuminemia and/or no immunosuppression (IS), in contrast to the classic nephrotic syndrome that remits with IS. Atypical remission variants were just as likely to relapse as the classical presentation. Only 24% of remission events were on maintenance therapy at relapse. Independent characteristics associated with relapses were higher maximal proteinuria while nephrotic; and in remission, higher nadir proteinuria, lower serum albumin, and higher blood pressure. Using these variables, we created a tool estimating the 1-year risk of relapse ranging from 9% to 80%, well-calibrated to the observed data. Conclusion In FSGS, relapses are frequent but predictable using independent clinical characteristics. We also provide evidence that atypical presentations remit and relapse following the same pattern as classic FSGS presentations. Treatment strategies to prolong remission duration should be addressed in future trials.
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Affiliation(s)
- Stéphan Troyanov
- Division of Nephrology, Department of Medicine, Hôpital du Sacré-Coeur de Montréal, University of Montréal, Montréal, Quebec, Canada
| | - Arenn Jauhal
- Division of Nephrology, Department of Medicine, University Health Network, University of Toronto, Toronto, Ontario, Canada
| | - Heather N. Reich
- Division of Nephrology, Department of Medicine, University Health Network, University of Toronto, Toronto, Ontario, Canada
| | - Michelle A. Hladunewich
- Division of Nephrology, Department of Medicine, Sunnybrook Health Science Center, University of Toronto, Toronto, Ontario, Canada
| | - Daniel C. Cattran
- Division of Nephrology, Department of Medicine, University Health Network, University of Toronto, Toronto, Ontario, Canada
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10
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Haeri H, Eisermann J, Schimm H, Büscher A, Hoyer P, Hinderberger D. Profound Changes in Functional Structure and Dynamics of Serum Albumin in Children with Nephrotic Syndrome: An Exploratory Research Study. J Med Chem 2023; 66:12115-12129. [PMID: 37648246 PMCID: PMC10510392 DOI: 10.1021/acs.jmedchem.3c00680] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2023] [Indexed: 09/01/2023]
Abstract
Patients with nephrotic syndrome (NS) suffer from urinary loss of albumin. As a cause, previous studies focused on the glomerular filter rather than analyzing the molecular properties of albumin itself. Later one was initiated by clinical observations indicating unexplained molecular alterations of human serum albumin (HSA) in an NS pediatric patient. Therefore, we examined serum from eight pediatric patients with steroid-sensitive and -resistant NS and compared it with serum from healthy subjects as well as commercial HSA. We used dynamic and electrophoretic light scattering to characterize the protein size and effective surface charge and electron paramagnetic resonance spectroscopy to measure the local environment and binding dynamics of up to seven fatty acids associated with HSA. Our findings suggest that pronounced differences in binding behavior and surface charge of HSA could enhance their filtration through the GBM, leading to direct toxicity of HSA to podocytes.
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Affiliation(s)
- Haleh
H. Haeri
- Physical
Chemistry, Complex Self-Organizing Systems, Martin Luther University
Halle-Wittenberg, Institute of Chemistry, Von Danckelmann-Platz 4, 06120 Halle (Saale), Germany
| | - Jana Eisermann
- Department
of Chemistry, Molecular Sciences Research Hub, Imperial College London, 82 Wood Ln, W12 0BZ London, U.K.
| | - Heike Schimm
- Physical
Chemistry, Complex Self-Organizing Systems, Martin Luther University
Halle-Wittenberg, Institute of Chemistry, Von Danckelmann-Platz 4, 06120 Halle (Saale), Germany
| | - Anja Büscher
- Universitätsklinikum
Essen (AöR), Klinik für Kinderheilkunde II, Zentrum
für Kinder- und Jugendmedizin, Hufelandstraße 55, D-45147 Essen, Germany
| | - Peter Hoyer
- Universitätsklinikum
Essen (AöR), Klinik für Kinderheilkunde II, Zentrum
für Kinder- und Jugendmedizin, Hufelandstraße 55, D-45147 Essen, Germany
| | - Dariush Hinderberger
- Physical
Chemistry, Complex Self-Organizing Systems, Martin Luther University
Halle-Wittenberg, Institute of Chemistry, Von Danckelmann-Platz 4, 06120 Halle (Saale), Germany
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11
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Ge L, Liu J, Lin B, Qin X. Progress in understanding primary glomerular disease: insights from urinary proteomics and in-depth analyses of potential biomarkers based on bioinformatics. Crit Rev Clin Lab Sci 2023:1-20. [PMID: 36815270 DOI: 10.1080/10408363.2023.2178378] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/24/2023]
Abstract
Chronic kidney disease (CKD) has become a global public health challenge. While primary glomerular disease (PGD) is one of the leading causes of CKD, the specific pathogenesis of PGD is still unclear. Accurate diagnosis relies largely on invasive renal biopsy, which carries risks of bleeding, pain, infection and kidney vein thrombosis. Problems with the biopsy procedure include lack of glomeruli in the tissue obtained, and the sampling site not being reflective of the overall lesion in the kidney. Repeated renal biopsies to monitor disease progression cannot be performed because of the significant risks of bleeding and kidney vein thrombosis. On the other hand, urine collection, a noninvasive method, can be performed repeatedly, and urinary proteins can reflect pathological changes in the urinary system. Advancements in proteomics technologies, especially mass spectrometry, have facilitated the identification of candidate biomarkers in different pathological types of PGD. Such biomarkers not only provide insights into the pathogenesis of PGD but also are important for diagnosis, monitoring treatment, and prognosis. In this review, we summarize the findings from studies that have used urinary proteomics, among other omics screens, to identify potential biomarkers for different types of PGD. Moreover, we performed an in-depth bioinformatic analysis to gain a deeper understanding of the biological processes and protein-protein interaction networks in which these candidate biomarkers may participate. This review, including a description of an integrated analysis method, is intended to provide insights into the pathogenesis, noninvasive diagnosis, and personalized treatment efforts of PGD and other associated diseases.
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Affiliation(s)
- Lili Ge
- Department of Laboratory Medicine, Shengjing Hospital of China Medical University, Shenyang, China.,Liaoning Clinical Research Center for Laboratory Medicine, Shenyang, China
| | - Jianhua Liu
- Department of Laboratory Medicine, Shengjing Hospital of China Medical University, Shenyang, China.,Liaoning Clinical Research Center for Laboratory Medicine, Shenyang, China
| | - Baoxu Lin
- Department of Laboratory Medicine, Shengjing Hospital of China Medical University, Shenyang, China.,Liaoning Clinical Research Center for Laboratory Medicine, Shenyang, China
| | - Xiaosong Qin
- Department of Laboratory Medicine, Shengjing Hospital of China Medical University, Shenyang, China.,Liaoning Clinical Research Center for Laboratory Medicine, Shenyang, China
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12
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Precise clinicopathologic findings for application of genetic testing in pediatric kidney transplant recipients with focal segmental glomerulosclerosis/steroid-resistant nephrotic syndrome. Pediatr Nephrol 2023; 38:417-429. [PMID: 35655039 DOI: 10.1007/s00467-022-05604-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/02/2022] [Revised: 04/29/2022] [Accepted: 04/29/2022] [Indexed: 01/10/2023]
Abstract
BACKGROUND Establishing a molecular genetic diagnosis of focal segmental glomerulosclerosis (FSGS)/steroid-resistant nephrotic syndrome (SRNS) can be useful for predicting post-transplant recurrence. Monogenic causes are reportedly present in approximately 20-30% of patients with FSGS/SRNS. However, the characteristics of patients who are likely to have a monogenic cause remain to be determined. METHODS Pediatric recipients with SRNS and/or biopsy-proven FSGS who underwent their first kidney transplantation at our center between 1999 and 2019 were analyzed. Patients with secondary FSGS/SRNS were excluded. The recipients were divided into three groups: familial/syndromic, presumed primary, and undetermined FSGS/SRNS. Patients who met all of the following criteria were categorized as having presumed primary FSGS/SRNS: (i) nephrotic syndrome, (ii) complete or partial remission with initial steroid therapy and/or additional immunosuppressive therapies, and (iii) diffuse foot process effacement on electron microscopy in the native kidney biopsy. All patients underwent genetic testing using next-generation sequencing. RESULTS Twenty-four patients from 23 families were analyzed in this study. Pathogenic or likely pathogenic variants in FSGS/SRNS-related genes were identified in four of four families, zero of eight families, and 10 of 11 families with familial/syndromic, presumed primary, and undetermined FSGS/SRNS, respectively. Post-transplant recurrence only occurred in patients with presumed primary FSGS/SRNS. CONCLUSIONS Our systematic approach based on precise clinicopathological findings including nephrotic syndrome, treatment responses, and diffuse foot process effacement might be useful to differentiate pediatric kidney transplant recipients with FSGS/SRNS who are likely to have a monogenic cause from patients who are not, and to predict post-transplant recurrence. A higher resolution version of the Graphical abstract is available as Supplementary information.
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13
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Abstract
The prevalence of obesity has increased dramatically during the past decades, which has been a major health problem. Since 1975, the number of people with obesity worldwide has nearly tripled. An increasing number of studies find obesity as a driver of chronic kidney disease (CKD) progression, and the mechanisms are complex and include hemodynamic changes, inflammation, oxidative stress, and activation of the renin-angiotensin-aldosterone system (RAAS). Obesity-related kidney disease is characterized by glomerulomegaly, which is often accompanied by localized and segmental glomerulosclerosis lesions. In these patients, the early symptoms are atypical, with microproteinuria being the main clinical manifestation and nephrotic syndrome being rare. Weight loss and RAAS blockers have a protective effect on obesity-related CKD, but even so, a significant proportion of patients eventually progress to end-stage renal disease despite treatment. Thus, it is critical to comprehend the mechanisms underlying obesity-related CKD to create new tactics for slowing or stopping disease progression. In this review, we summarize current knowledge on the mechanisms of obesity-related kidney disease, its pathological changes, and future perspectives on its treatment.
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Affiliation(s)
- Zongmiao Jiang
- Department of Endocrinology and Metabolism, The First Hospital of Jilin University, Changchun, China
| | - Yao Wang
- Department of Orthopedics, The Second Hospital Jilin University, Changchun, China
| | - Xue Zhao
- Department of Endocrinology and Metabolism, The First Hospital of Jilin University, Changchun, China
| | - Haiying Cui
- Department of Endocrinology and Metabolism, The First Hospital of Jilin University, Changchun, China
| | - Mingyue Han
- Department of Endocrinology and Metabolism, The First Hospital of Jilin University, Changchun, China
| | - Xinhua Ren
- Department of Endocrinology and Metabolism, The First Hospital of Jilin University, Changchun, China
| | - Xiaokun Gang
- Department of Endocrinology and Metabolism, The First Hospital of Jilin University, Changchun, China
| | - Guixia Wang
- Department of Endocrinology and Metabolism, The First Hospital of Jilin University, Changchun, China
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14
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Burt MA, Kalejaiye TD, Bhattacharya R, Dimitrakakis N, Musah S. Adriamycin-Induced Podocyte Injury Disrupts the YAP-TEAD1 Axis and Downregulates Cyr61 and CTGF Expression. ACS Chem Biol 2022; 17:3341-3351. [PMID: 34890187 DOI: 10.1021/acschembio.1c00678] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
The most severe forms of kidney diseases are often associated with irreversible damage to the glomerular podocytes, the highly specialized epithelial cells that encase glomerular capillaries and regulate the removal of toxins and waste from the blood. Several studies revealed significant changes to podocyte cytoskeletal structure during disease onset, suggesting possible roles of cellular mechanosensing in podocyte responses to injury. Still, this topic remains underexplored partly due to the lack of appropriate in vitro models that closely recapitulate human podocyte biology. Here, we leveraged our previously established method for the derivation of mature podocytes from human induced pluripotent stem cells (hiPSCs) to help uncover the roles of yes-associated protein (YAP), a transcriptional coactivator and mechanosensor, in podocyte injury response. We found that while the total expression levels of YAP remain relatively unchanged during Adriamycin (ADR)-induced podocyte injury, the YAP target genes connective tissue growth factor (CTGF) and cysteine-rich angiogenic inducer 61 (Cyr61) are significantly downregulated. Intriguingly, TEAD1 is significantly downregulated in podocytes injured with ADR. By examining multiple independent modes of cellular injury, we found that CTGF and Cyr61 expression are downregulated only when podocytes were exposed to molecules known to disrupt the cell's mechanical integrity or cytoskeletal structure. To our knowledge, this is the first report that the YAP-TEAD1 signaling axis is disrupted when stem cell-derived human podocytes experience biomechanical injury. Together, these results could help improve the understanding of kidney disease mechanisms and highlight CTGF and Cyr61 as potential therapeutic targets or biomarkers for patient stratification.
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Affiliation(s)
- Morgan A Burt
- Department of Biomedical Engineering, Duke University, Durham, North Carolina 27708, United States
| | - Titilola D Kalejaiye
- Department of Biomedical Engineering, Duke University, Durham, North Carolina 27708, United States
| | - Rohan Bhattacharya
- Department of Biomedical Engineering, Duke University, Durham, North Carolina 27708, United States
- Center for Biomolecular and Tissue Engineering, Duke University, Durham, North Carolina 27708, United States
| | - Nikolaos Dimitrakakis
- Wyss Institute for Biologically Inspired Engineering, Harvard University, Boston, Massachusetts 02115, United States
| | - Samira Musah
- Department of Biomedical Engineering, Duke University, Durham, North Carolina 27708, United States
- Center for Biomolecular and Tissue Engineering, Duke University, Durham, North Carolina 27708, United States
- Department of Medicine, Division of Nephrology, Duke University School of Medicine, Durham, North Carolina 27710, United States
- Department of Cell Biology, Duke University, Durham, North Carolina 27710, United States
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15
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Liew A, Gibson KL. How I Treat Focal Segmental Glomerulosclerosis. Clin J Am Soc Nephrol 2022; 17:1814-1816. [PMID: 35998974 PMCID: PMC9718025 DOI: 10.2215/cjn.06850622] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Affiliation(s)
- Adrian Liew
- The Kidney & Transplant Practice, Mount Elizabeth Novena Hospital, Singapore
| | - Keisha L. Gibson
- University of North Carolina Kidney Center at Chapel Hill, Chapel Hill, North Carolina
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16
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Jauhal A, Reich HN, Hladunewich M, Barua M, Hansen BE, Naimark D, Troyanov S, Cattran DC. Quantifying the benefits of remission duration in focal and segmental glomerulosclerosis. Nephrol Dial Transplant 2022; 38:950-960. [PMID: 35948275 PMCID: PMC10064837 DOI: 10.1093/ndt/gfac238] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2022] [Indexed: 11/13/2022] Open
Abstract
BACKGROUND Although the clinical benefit of obtaining a remission in proteinuria in nephrotic patients with focal and segmental glomerulosclerosis (FSGS) is recognized, the long-term value of maintaining it and the impact of relapses on outcome are not well described. METHODS We examined the impact of remissions and relapses on either a 50% decline in kidney function or ESKD (combined event) using time-dependent and landmark analyses in a retrospective study of all patients from the Toronto Glomerulonephritis Registry with biopsy-proven FSGS, established nephrotic-range proteinuria and at least one remission. RESULTS In the 203 FSGS individuals with a remission, 89 never relapsed and 114 experienced at least one relapse. The first recurrence was often followed by a repeating pattern of remission and relapse. The 10-year survival from a combined event was 15% higher in those with no relapse versus those with any relapse. This smaller than anticipated difference was related to the favorable outcome in individuals whose relapses quickly remitted. Relapsers who ultimately ended in remission (n = 46) versus in relapse (n = 68) experienced a 91% and 32% 7-year event survival (p<0.001). Using time-varying survival analyses that considered all periods of remission and relapse in every patient and adjusting for each period's initial eGFR, the state of relapse was associated with a 2.17 (95%CI,1.32-3.58, p = 0.002) greater risk of experiencing a combined event even in this FSGS remission cohort. CONCLUSIONS In FSGS, unless remissions are maintained and relapses avoided, long-term renal survival remains poor. Treatment strategies addressing remission duration remain poorly defined and should be an essential question in future trials.
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Affiliation(s)
- Arenn Jauhal
- Division of Nephrology, Department of Medicine, University Health Network, University of Toronto, Toronto, Ontario, Canada
| | - Heather N Reich
- Division of Nephrology, Department of Medicine, University Health Network, University of Toronto, Toronto, Ontario, Canada
| | - Michelle Hladunewich
- Division of Nephrology, Department of Medicine, Sunnybrook Health Science Center, University of Toronto, Toronto, Ontario, Canada
| | - Moumita Barua
- Division of Nephrology, Department of Medicine, University Health Network, University of Toronto, Toronto, Ontario, Canada
| | - Bettina E Hansen
- Institute of Health Policy, Management and Evaluation, University of Toronto, Toronto, Canada
| | - David Naimark
- Division of Nephrology, Department of Medicine, Sunnybrook Health Science Center, University of Toronto, Toronto, Ontario, Canada
| | - Stéphan Troyanov
- Division of Nephrology, Department of Medicine, Hôpital du Sacré-Coeur de Montréal, University of Montreal, Montreal, Quebec, Canada
| | - Daniel C Cattran
- Division of Nephrology, Department of Medicine, University Health Network, University of Toronto, Toronto, Ontario, Canada
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17
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Elsaid HO, Furriol J, Blomqvist M, Diswall M, Leh S, Gharbi N, Anonsen JH, Babickova J, Tøndel C, Svarstad E, Marti HP, Krause M. Reduced α-galactosidase A activity in zebrafish ( Danio rerio) mirrors distinct features of Fabry nephropathy phenotype. Mol Genet Metab Rep 2022; 31:100851. [PMID: 35242583 PMCID: PMC8857658 DOI: 10.1016/j.ymgmr.2022.100851] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2022] [Accepted: 02/13/2022] [Indexed: 10/28/2022] Open
Abstract
Fabry disease (FD) is a rare genetic lysosomal storage disorder, resulting from partial or complete lack of alpha-galactosidase A (α-GAL) enzyme, leading to systemic accumulation of substrate glycosphingolipids with a broad range of tissue damage. Current in vivo models are laborious, expensive, and fail to adequately mirror the complex FD physiopathology. To address these issues, we developed an innovative FD model in zebrafish. Zebrafish GLA gene encoding α-GAL enzyme presents a high (>70%) homology with its human counterpart, and the corresponding protein has a similar tissue distribution, as evaluated by immunohistochemistry. Moreover, a similar enzymatic activity in different life stages could be demonstrated. By using CRISPR/Cas9 technology, we generated a mutant zebrafish with decreased GLA gene expression, and decreased expression of the specific gene product in the kidney. Mutant animals showed higher plasma creatinine levels and proteinuria. Transmission electron microscopy (TEM) studies documented an increased podocyte foot process width (FPW) in mutant, as compared to wild type zebrafish. This zebrafish model reliably mirrors distinct features of human FD and could be advantageously used for the identification of novel biomarkers and for an effective screening of innovative therapeutic approaches.
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Affiliation(s)
| | - Jessica Furriol
- Department of Clinical Medicine, University of Bergen, Bergen, Norway
- Department of Medicine, Haukeland University Hospital, Bergen, Norway
| | - Maria Blomqvist
- Department of Clinical Chemistry, Sahlgrenska University Hospital, Gothenburg, Sweden
- Department of Laboratory Medicine, Institute of Biomedicine, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden
| | - Mette Diswall
- Department of Clinical Chemistry, Sahlgrenska University Hospital, Gothenburg, Sweden
- Department of Laboratory Medicine, Institute of Biomedicine, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden
| | - Sabine Leh
- Department of Clinical Medicine, University of Bergen, Bergen, Norway
- Department of Pathology, Haukeland University Hospital, Bergen, Norway
| | - Naouel Gharbi
- Department of Climate & Environment, Industrial Biotechnology, NORCE, Bergen, Mekjarvik, Norway
| | - Jan Haug Anonsen
- Department of Climate & Environment, Industrial Biotechnology, NORCE, Bergen, Mekjarvik, Norway
| | - Janka Babickova
- Department of Clinical Medicine, University of Bergen, Bergen, Norway
- Institute of Molecular Biomedicine, Faculty of Medicine, Comenius University, Bratislava, Slovakia
| | - Camilla Tøndel
- Department of Clinical Medicine, University of Bergen, Bergen, Norway
- Department of Pediatrics, Haukeland University Hospital, Bergen, Norway
| | - Einar Svarstad
- Department of Clinical Medicine, University of Bergen, Bergen, Norway
| | - Hans-Peter Marti
- Department of Clinical Medicine, University of Bergen, Bergen, Norway
- Department of Medicine, Haukeland University Hospital, Bergen, Norway
| | - Maximilian Krause
- Computational Biology Unit, Department of Informatics, University of Bergen, Bergen, Norway
- Sars Centre for Molecular Marine Biology, University of Bergen, Bergen, Norway
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18
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Lin DW, Chang CC, Hsu YC, Lin CL. New Insights into the Treatment of Glomerular Diseases: When Mechanisms Become Vivid. Int J Mol Sci 2022; 23:3525. [PMID: 35408886 PMCID: PMC8998908 DOI: 10.3390/ijms23073525] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2022] [Revised: 03/18/2022] [Accepted: 03/22/2022] [Indexed: 12/23/2022] Open
Abstract
Treatment for glomerular diseases has been extrapolated from the experience of other autoimmune disorders while the underlying pathogenic mechanisms were still not well understood. As the classification of glomerular diseases was based on patterns of juries instead of mechanisms, treatments were typically the art of try and error. With the advancement of molecular biology, the role of the immune agent in glomerular diseases is becoming more evident. The four-hit theory based on the discovery of gd-IgA1 gives a more transparent outline of the pathogenesis of IgA nephropathy (IgAN), and dysregulation of Treg plays a crucial role in the pathogenesis of minimal change disease (MCD). An epoch-making breakthrough is the discovery of PLA2R antibodies in the primary membranous nephropathy (pMN). This is the first biomarker applied for precision medicine in kidney disease. Understanding the immune system's role in glomerular diseases allows the use of various immunosuppressants or other novel treatments, such as complement inhibitors, to treat glomerular diseases more reasonable. In this era of advocating personalized medicine, it is inevitable to develop precision medicine with mechanism-based novel biomarkers and novel therapies in kidney disease.
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Affiliation(s)
- Da-Wei Lin
- Department of Internal Medicine, St. Martin De Porres Hospital, Chiayi 60069, Taiwan;
| | - Cheng-Chih Chang
- Department of Surgery, Chang Gung Memorial Hospital, Chiayi 613016, Taiwan;
| | - Yung-Chien Hsu
- Department of Nephrology, Chang Gung Memorial Hospital, Chiayi 613016, Taiwan
- Kidney and Diabetic Complications Research Team (KDCRT), Chang Gung Memorial Hospital, Chiayi 613016, Taiwan
| | - Chun-Liang Lin
- Department of Nephrology, Chang Gung Memorial Hospital, Chiayi 613016, Taiwan
- Kidney and Diabetic Complications Research Team (KDCRT), Chang Gung Memorial Hospital, Chiayi 613016, Taiwan
- Division of Chinese Materia Medica Development, National Research Institute of Chinese Medicine, Taipei 613016, Taiwan
- Kidney Research Center, Chang Gung Memorial Hospital, Taipei 613016, Taiwan
- Center for Shockwave Medicine and Tissue Engineering, Chang Gung Memorial Hospital, Kaohsiung 833253, Taiwan
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19
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Ravaglia F, Melica ME, Angelotti ML, De Chiara L, Romagnani P, Lasagni L. The Pathology Lesion Patterns of Podocytopathies: How and why? Front Cell Dev Biol 2022; 10:838272. [PMID: 35281116 PMCID: PMC8907833 DOI: 10.3389/fcell.2022.838272] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2021] [Accepted: 02/07/2022] [Indexed: 11/13/2022] Open
Abstract
Podocytopathies are a group of proteinuric glomerular disorders driven by primary podocyte injury that are associated with a set of lesion patterns observed on kidney biopsy, i.e., minimal changes, focal segmental glomerulosclerosis, diffuse mesangial sclerosis and collapsing glomerulopathy. These unspecific lesion patterns have long been considered as independent disease entities. By contrast, recent evidence from genetics and experimental studies demonstrated that they represent signs of repeated injury and repair attempts. These ongoing processes depend on the type, length, and severity of podocyte injury, as well as on the ability of parietal epithelial cells to drive repair. In this review, we discuss the main pathology patterns of podocytopathies with a focus on the cellular and molecular response of podocytes and parietal epithelial cells.
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Affiliation(s)
| | - Maria Elena Melica
- Department of Experimental and Clinical Biomedical Sciences “Mario Serio”, University of Florence, Florence, Italy
| | - Maria Lucia Angelotti
- Department of Experimental and Clinical Biomedical Sciences “Mario Serio”, University of Florence, Florence, Italy
| | - Letizia De Chiara
- Department of Experimental and Clinical Biomedical Sciences “Mario Serio”, University of Florence, Florence, Italy
| | - Paola Romagnani
- Department of Experimental and Clinical Biomedical Sciences “Mario Serio”, University of Florence, Florence, Italy
- Nephrology Unit, Meyer Children’s Hospital, Florence, Italy
| | - Laura Lasagni
- Department of Experimental and Clinical Biomedical Sciences “Mario Serio”, University of Florence, Florence, Italy
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20
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Wang F, Fan J, Pei T, He Z, Zhang J, Ju L, Han Z, Wang M, Xiao W. Effects of Shenkang Pills on Early-Stage Diabetic Nephropathy in db/db Mice via Inhibiting AURKB/RacGAP1/RhoA Signaling Pathway. Front Pharmacol 2022; 13:781806. [PMID: 35222021 PMCID: PMC8873791 DOI: 10.3389/fphar.2022.781806] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2021] [Accepted: 01/17/2022] [Indexed: 12/22/2022] Open
Abstract
Diabetic nephropathy (DN) is the leading cause of end-stage renal disease, so there is an urgent need to suppress its development at early stage. Shenkang pills (SKP) are a hospital prescription selected and optimized from effective traditional Chinese medicinal formulas for clinical treatment of DN. In the present study, liquid chromatography-quadrupole-time of flight-mass spectrometry (LC-Q-TOF-MS) and total contents qualification were applied to generate a quality control standard of SKP. For verifying the therapeutic effects of SKP, db/db mice were administered intragastrically with SKP at a human-equivalent dose (1.82 g/kg) for 4 weeks. Moreover, the underlying mechanism of SKP were analyzed by the renal RNA sequencing and network pharmacology. LC-Q-TOF-MS identified 46 compounds in SKP. The total polysaccharide and organic acid content in SKP were 4.60 and 0.11 mg/ml, respectively, while the total flavonoid, saponin, and protein content were 0.25, 0.31, and 0.42 mg/ml, respectively. Treatment of SKP significantly reduced fasting blood glucose, improved renal function, and ameliorated glomerulosclerosis and focal foot processes effacement in db/db mice. In addition, SKP protected podocytes from injury by increasing nephrin and podocin expression. Furthermore, transcriptome analyses revealed that 430 and 288 genes were up and down-regulated in mice treated with SKP, relative to untreated controls. Gene ontology enrichment analysis revealed that the differentially expressed genes mainly involved in modulation of cell division and chromosome segregation. Weighted gene co-expression network analysis and network pharmacology analysis indicated that aurora kinase B (AURKB), Rac GTPase activating protein 1 (RacGAP1) and SHC binding, and spindle associated 1 (shcbp1) might be the core targets of SKP. This protein and Ras homolog family member A (RhoA) were found overexpression in db/db mice, but significantly decreased with SKP treatment. We conclude that SKP can effectively treat early-stage DN and improve renal podocyte dysfunction. The mechanism may involve down-regulation of the AURKB/RacGAP1/RhoA pathway.
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Affiliation(s)
| | | | | | | | | | | | | | | | - Wei Xiao
- *Correspondence: Mingqing Wang, ; Wei Xiao,
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21
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Sanchez-Martin I, Magalhães P, Ranjzad P, Fatmi A, Richard F, Manh TPV, Saurin AJ, Feuillet G, Denis C, Woolf AS, Schanstra JP, Zürbig P, Caubit X, Fasano L. Haploinsufficiency of the mouse Tshz3 gene leads to kidney defects. Hum Mol Genet 2021; 31:1921-1945. [PMID: 34919690 DOI: 10.1093/hmg/ddab362] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2021] [Revised: 12/09/2021] [Accepted: 12/10/2021] [Indexed: 11/14/2022] Open
Abstract
Renal tract defects and autism spectrum disorder (ASD) deficits represent the phenotypic core of the 19q12 deletion syndrome caused by the loss of one copy of the TSHZ3 gene. While a proportion of Tshz3 heterozygous (Tshz3+/lacZ) mice display ureteral defects, no kidney defects have been reported in these mice. The purpose of this study was to characterize the expression of Tshz3 in adult kidney as well as the renal consequences of embryonic haploinsufficiency of Tshz3 by analyzing the morphology and function of Tshz3 heterozygous adult kidney. Here, we described Tshz3 expression in the smooth muscle and stromal cells lining the renal pelvis, the papilla and glomerular endothelial cells (GEnCs) of the adult kidney as well as in the proximal nephron tubules in neonatal mice. Histological analysis showed that Tshz3+/lacZ adult kidney had an average of 29% fewer glomeruli than wild type kidney. Transmission electron microscopy (TEM) of Tshz3+/lacZ glomeruli revealed a reduced thickness of the glomerular basement membrane and a larger foot process width. Compared to wild type, Tshz3+/lacZ mice showed lower blood urea, phosphates, magnesium and potassium at 2 months of age. At the molecular level, transcriptome analysis identified differentially expressed genes related to inflammatory processes in Tshz3+/lacZ compare to wild type (WT; control) adult kidneys. Lastly, analysis of the urinary peptidome revealed 33 peptides associated with Tshz3+/lacZ adult mice. These results provide the first evidence that in the mouse Tshz3 haploinsufficiency leads to cellular, molecular and functional abnormalities in the adult mouse kidney.
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Affiliation(s)
| | | | - Parisa Ranjzad
- Division of Cell Matrix Biology and Regenerative Medicine, School of Biological Sciences, Faculty of Biology Medicine and Health, University of Manchester, UK
| | - Ahmed Fatmi
- Aix Marseille Univ, CNRS, IBDM, UMR7288, Marseille, France
| | | | - Thien Phong Vu Manh
- Aix Marseille Univ, CNRS, INSERM, CIML, Centre d'Immunologie de Marseille-Luminy, Marseille, France
| | | | - Guylène Feuillet
- Institut National de la Santé et de la Recherche Médicale (INSERM), U1297, Institut of Cardiovascular and Metabolic Disease, Toulouse, France.,Université Toulouse III Paul-Sabatier, Toulouse, France
| | - Colette Denis
- Institut National de la Santé et de la Recherche Médicale (INSERM), U1297, Institut of Cardiovascular and Metabolic Disease, Toulouse, France.,Université Toulouse III Paul-Sabatier, Toulouse, France
| | - Adrian S Woolf
- Division of Cell Matrix Biology and Regenerative Medicine, School of Biological Sciences, Faculty of Biology Medicine and Health, University of Manchester, UK.,Royal Manchester Children's Hospital, Manchester University NHS Foundation Trust, Manchester Academic Health Science Centre, Manchester, UK
| | - Joost P Schanstra
- Institut National de la Santé et de la Recherche Médicale (INSERM), U1297, Institut of Cardiovascular and Metabolic Disease, Toulouse, France.,Université Toulouse III Paul-Sabatier, Toulouse, France
| | | | - Xavier Caubit
- Aix Marseille Univ, CNRS, IBDM, UMR7288, Marseille, France
| | - Laurent Fasano
- Aix Marseille Univ, CNRS, IBDM, UMR7288, Marseille, France
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22
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Hudkins KL, Li X, Holland AL, Swaminathan S, Alpers CE. Regression of diabetic nephropathy by treatment with empagliflozin in BTBR ob/ob mice. Nephrol Dial Transplant 2021; 37:847-859. [PMID: 34865099 DOI: 10.1093/ndt/gfab330] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2021] [Indexed: 11/14/2022] Open
Abstract
BACKGROUND The SGLT2 inhibitor empagliflozin lowers blood glucose via reduced tubular reabsorption of filtered glucose and is an important new therapy for diabetic nephropathy (DN). This study tested whether treatment with empagliflozin would ameliorate proteinuria and the pathologic alterations of DN including podocyte number and integrity in the leptin deficient BTBR ob/ob mouse model of DN. METHODS Study cohorts included wild type BTBR mice, untreated diabetic BTBR ob/ob mice, and mice treated with empagliflozin for six weeks after development of established DN at 18 weeks of age. RESULTS Hyperglycemia, proteinuria, serum creatinine, accumulation of mesangial matrix and the extent of mesangiolysis were reversed with empagliflozin treatment. Treatment with empagliflozin resulted in increased podocyte number and podocyte density, improvement in the degree of podocyte foot process effacement and parietal epithelial cell activation. SGLT2 inhibition reduced renal oxidative stress, measured by urinary excretion of markers of RNA/DNA damage and in situ demonstration of decreased carbonyl oxidation. There was no discernable difference in accumulations of advanced glycation endproducts by immunohistochemistry. CONCLUSION The structural improvements seen in BTBR ob/ob mice treated with empagliflozin provide insight into potential long term benefits for humans with DN, for whom there is no comparable biopsy information to identify structural changes effected by SGLT2 inhibition. The findings suggest SGLT2 inhibition may ameliorate diabetic nephropathy through glucose lowering-dependent and -independent mechanisms that lead to podocyte restoration and delay or reversal of the disease progress.
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Affiliation(s)
- Kelly L Hudkins
- Department of Pathology, University of Washington, Seattle WA, USA
| | - Xianwu Li
- Department of Pathology, University of Washington, Seattle WA, USA
| | | | | | - Charles E Alpers
- Department of Pathology, University of Washington, Seattle WA, USA
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23
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Rovin BH, Adler SG, Barratt J, Bridoux F, Burdge KA, Chan TM, Cook HT, Fervenza FC, Gibson KL, Glassock RJ, Jayne DR, Jha V, Liew A, Liu ZH, Mejía-Vilet JM, Nester CM, Radhakrishnan J, Rave EM, Reich HN, Ronco P, Sanders JSF, Sethi S, Suzuki Y, Tang SC, Tesar V, Vivarelli M, Wetzels JF, Floege J. KDIGO 2021 Clinical Practice Guideline for the Management of Glomerular Diseases. Kidney Int 2021; 100:S1-S276. [PMID: 34556256 DOI: 10.1016/j.kint.2021.05.021] [Citation(s) in RCA: 748] [Impact Index Per Article: 249.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2021] [Accepted: 05/25/2021] [Indexed: 12/13/2022]
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24
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Miao J, Pinto E Vairo F, Hogan MC, Erickson SB, El Ters M, Bentall AJ, Kukla A, Greene EL, Hernandez LH, Sethi S, Lazaridis KN, Pichurin PN, Lisi E, Prochnow CA, Zand L, Fervenza FC. Identification of Genetic Causes of Focal Segmental Glomerulosclerosis Increases With Proper Patient Selection. Mayo Clin Proc 2021; 96:2342-2353. [PMID: 34120753 DOI: 10.1016/j.mayocp.2021.01.037] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/04/2020] [Revised: 01/25/2021] [Accepted: 01/28/2021] [Indexed: 12/18/2022]
Abstract
OBJECTIVE To increase the likelihood of finding a causative genetic variant in patients with a focal segmental glomerulosclerosis (FSGS) lesion, clinical and histologic characteristics were analyzed. PATIENTS AND METHODS Individuals 18 years and older with an FSGS lesion on kidney biopsy evaluated at Mayo Clinic from November 1, 1999, through October 31, 2019, were divided into 4 groups based on clinical and histologic characteristics: primary FSGS, secondary FSGS with known cause, secondary FSGS without known cause, and undetermined FSGS. A targeted gene panel and a customized gene panel retrieved from exome sequencing were performed. RESULTS The overall rate of detection of a monogenic cause was 42.9% (21/49). Individuals with undetermined FSGS had the highest rate of positivity (87.5%; 7/8) followed by secondary FSGS without an identifiable cause (61.5%; 8/13) and secondary FSGS with known cause (33.3%; 5/15). Four of 5 (80%) individuals in the latter group who had positive genetic testing results also had a family history of kidney disease. Univariate analysis showed that family history of kidney disease (odds ratio [OR], 13.8; 95% CI, 3.7 to 62.4; P<.001), absence of nephrotic syndrome (OR, 8.2; 95% CI, 1.9 to 58.1; P=.004), and female sex (OR, 5.1; 95% CI, 1.5 to 19.9; P=.01) were strong predictors of finding a causative genetic variant in the entire cohort. The most common variants were in the collagen genes (52.4%; 11/21), followed by the podocyte genes (38.1%; 8/21). CONCLUSION In adults with FSGS lesions, proper selection of patients increases the rate of positive genetic testing significantly. The majority of individuals with undetermined FSGS in whom the clinical presentation and histologic parameters are discordant had a genetic diagnosis.
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Affiliation(s)
- Jing Miao
- Division of Nephrology and Hypertension, Mayo Clinic, Rochester, MN
| | - Filippo Pinto E Vairo
- Department of Clinical Genomics, Mayo Clinic, Rochester, MN; Center for Individualized Medicine, Mayo Clinic, Rochester, MN
| | - Marie C Hogan
- Division of Nephrology and Hypertension, Mayo Clinic, Rochester, MN
| | | | - Mireille El Ters
- Division of Nephrology and Hypertension, Mayo Clinic, Rochester, MN
| | - Andrew J Bentall
- Division of Nephrology and Hypertension, Mayo Clinic, Rochester, MN
| | - Aleksandra Kukla
- Division of Nephrology and Hypertension, Mayo Clinic, Rochester, MN
| | - Eddie L Greene
- Division of Nephrology and Hypertension, Mayo Clinic, Rochester, MN
| | | | - Sanjeev Sethi
- Department of Pathology and Laboratory Medicine, Mayo Clinic, Rochester, MN
| | | | | | - Emily Lisi
- Center for Individualized Medicine, Mayo Clinic, Rochester, MN
| | | | - Ladan Zand
- Division of Nephrology and Hypertension, Mayo Clinic, Rochester, MN.
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25
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De Vriese AS, Wetzels JF, Glassock RJ, Sethi S, Fervenza FC. Therapeutic trials in adult FSGS: lessons learned and the road forward. Nat Rev Nephrol 2021; 17:619-630. [PMID: 34017116 PMCID: PMC8136112 DOI: 10.1038/s41581-021-00427-1] [Citation(s) in RCA: 50] [Impact Index Per Article: 16.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/09/2021] [Indexed: 02/03/2023]
Abstract
Focal segmental glomerulosclerosis (FSGS) is not a specific disease entity but a lesion that primarily targets the podocyte. In a broad sense, the causes of the lesion can be divided into those triggered by a presumed circulating permeability factor, those that occur secondary to a process that might originate outside the kidneys, those caused by a genetic mutation in a podocyte or glomerular basement membrane protein, and those that arise through an as yet unidentifiable process, seemingly unrelated to a circulating permeability factor. A careful attempt to correctly stratify patients with FSGS based on their clinical presentation and pathological findings on kidney biopsy is essential for sound treatment decisions in individual patients. However, it is also essential for the rational design of therapeutic trials in FSGS. Greater recognition of the pathophysiology underlying podocyte stress and damage in FSGS will increase the likelihood that the cause of an FSGS lesion is properly identified and enable stratification of patients in future interventional trials. Such efforts will facilitate the identification of effective therapeutic agents.
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Affiliation(s)
- An S De Vriese
- Division of Nephrology and Infectious Diseases, AZ Sint-Jan Brugge, Brugge, Belgium
- Department of Internal Medicine, Ghent University, Ghent, Belgium
| | - Jack F Wetzels
- Department of Nephrology, Radboud University Medical Center, Radboud Institute for Health Sciences, Nijmegen, The Netherlands
| | - Richard J Glassock
- Department of Medicine, Geffen School of Medicine at UCLA, Los Angeles, CA, USA
| | - Sanjeev Sethi
- Department of Laboratory Medicine and Pathology, Mayo Clinic, Rochester, MN, USA
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26
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Degree of foot process effacement in patients with genetic focal segmental glomerulosclerosis: a single-center analysis and review of the literature. Sci Rep 2021; 11:12008. [PMID: 34103591 PMCID: PMC8187362 DOI: 10.1038/s41598-021-91520-9] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2021] [Accepted: 05/25/2021] [Indexed: 01/15/2023] Open
Abstract
Determining the cause of focal segmental glomerulosclerosis (FSGS) has crucial implications for evaluating the risk of posttransplant recurrence. The degree of foot process effacement (FPE) on electron micrographs (EM) of native kidney biopsies can reportedly differentiate primary FSGS from secondary FSGS. However, no systematic evaluation of FPE in genetic FSGS has been performed. In this study, percentage of FPE and foot process width (FPW) in native kidney biopsies were analyzed in eight genetic FSGS patients and nine primary FSGS patients. All genetic FSGS patients showed segmental FPE up to 38% and FPW below 2000 nm, while all primary FSGS patients showed diffuse FPE above 88% and FPW above 3000 nm. We reviewed the literature which described the degree of FPE in genetic FSGS patients and identified 38 patients with a description of the degree of FPE. The degree of FPE in patients with mutations in the genes encoding proteins associated with slit diaphragm and cytoskeletal proteins was varied, while almost all patients with mutations in other FSGS genes showed segmental FPE. In conclusion, the present study suggests that the degree of FPE in native kidney biopsies may be useful for differentiating some genetic FSGS patients from primary FSGS patients.
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27
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Matsumoto A, Matsui I, Katsuma Y, Yasuda S, Shimada K, Namba-Hamano T, Sakaguchi Y, Kaimori JY, Takabatake Y, Inoue K, Isaka Y. Quantitative Analyses of Foot Processes, Mitochondria, and Basement Membranes by Structured Illumination Microscopy Using Elastica-Masson- and Periodic-Acid-Schiff-Stained Kidney Sections. Kidney Int Rep 2021; 6:1923-1938. [PMID: 34307987 PMCID: PMC8258503 DOI: 10.1016/j.ekir.2021.04.021] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2021] [Accepted: 04/16/2021] [Indexed: 11/28/2022] Open
Abstract
Introduction Foot process effacement and mitochondrial fission associate with kidney disease pathogenesis. Electron microscopy is the gold-standard method for their visualization, but the observable area of electron microscopy is smaller than light microscopy. It is important to develop alternative ways to quantitatively evaluate these microstructural changes because the lesion site of renal diseases can be focal. Methods We analyzed elastica-Masson trichrome (EMT) and periodic acid-Schiff (PAS) stained kidney sections using structured illumination microscopy (SIM). Results EMT staining revealed three-dimensional (3D) structures of foot process, whereas ponceau xylidine acid fuchsin azophloxine solution induced fluorescence. Conversion of foot process images into their constituent frequencies by Fourier transform showed that the concentric square of (1/4)2-(1/16)2 in the power spectra (PS) included information for normal periodic structures of foot processes. Foot process integrity, assessed by PS, negatively correlated with proteinuria. EMT-stained sections revealed fragmented mitochondria in mice with mitochondrial injuries and patients with tubulointerstitial nephritis; Fourier transform quantified associated mitochondrial injury. Quantified mitochondrial damage in patients with immunoglobulin A (IgA) nephropathy predicted a decline in estimated glomerular filtration rate (eGFR) after kidney biopsy but did not correlate with eGFR at biopsy. PAS-stained sections, excited by a 640 nm laser, combined with the coefficient of variation values, quantified subtle changes in the basement membranes of patients with membranous nephropathy stage I. Conclusions Kidney microstructures are quantified from sections prepared in clinical practice using SIM.
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Affiliation(s)
- Ayumi Matsumoto
- Department of Nephrology, Osaka University Graduate School of Medicine, Osaka, Japan
| | - Isao Matsui
- Department of Nephrology, Osaka University Graduate School of Medicine, Osaka, Japan
| | - Yusuke Katsuma
- Department of Nephrology, Osaka University Graduate School of Medicine, Osaka, Japan
| | - Seiichi Yasuda
- Department of Nephrology, Osaka University Graduate School of Medicine, Osaka, Japan
| | - Karin Shimada
- Department of Nephrology, Osaka University Graduate School of Medicine, Osaka, Japan
| | - Tomoko Namba-Hamano
- Department of Nephrology, Osaka University Graduate School of Medicine, Osaka, Japan
| | - Yusuke Sakaguchi
- Department of Inter-Organ Communication Research in Kidney Disease, Osaka University Graduate School of Medicine, Osaka, Japan
| | - Jun-Ya Kaimori
- Department of Inter-Organ Communication Research in Kidney Disease, Osaka University Graduate School of Medicine, Osaka, Japan
| | - Yoshitsugu Takabatake
- Department of Nephrology, Osaka University Graduate School of Medicine, Osaka, Japan
| | - Kazunori Inoue
- Department of Nephrology, Osaka University Graduate School of Medicine, Osaka, Japan
| | - Yoshitaka Isaka
- Department of Nephrology, Osaka University Graduate School of Medicine, Osaka, Japan
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28
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Fukusumi Y, Yasuda H, Zhang Y, Kawachi H. Nephrin-Ephrin-B1-Na +/H + Exchanger Regulatory Factor 2-Ezrin-Actin Axis Is Critical in Podocyte Injury. THE AMERICAN JOURNAL OF PATHOLOGY 2021; 191:1209-1226. [PMID: 33887216 DOI: 10.1016/j.ajpath.2021.04.004] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/15/2020] [Revised: 03/13/2021] [Accepted: 04/05/2021] [Indexed: 10/21/2022]
Abstract
Ephrin-B1 is one of the critical components of the slit diaphragm of kidney glomerular podocyte. However, the precise function of ephrin-B1 is unclear. To clarify the function of ephrin-B1, ephrin-B1-associated molecules were studied. RNA-sequencing analysis suggested that Na+/H+ exchanger regulatory factor 2 (NHERF2), a scaffolding protein, is associated with ephrin-B1. NHERF2 was expressed at the apical area and the slit diaphragm, and interacted with the nephrin-ephrin-B1 complex at the slit diaphragm. The nephrin-ephrin-B1-NHERF2 complex interacted with ezrin bound to F-actin. NHERF2 bound ephrin-B1 via its first postsynaptic density protein-95/disks large/zonula occludens-1 domain, and podocalyxin via its second postsynaptic density protein-95/disks large/zonula occludens-1 domain. Both in vitro analyses with human embryonic kidney 293 cells and in vivo study with rat nephrotic model showed that stimulaiton of the slit diaphragm, phosphorylation of nephrin and ephrin-B1, and dephosphorylation of NHERF2 and ezrin, disrupted the linkages of ephrin-B1-NHERF2 and NHERF2-ezrin. It is conceivable that the linkage of nephrin-ephrin-B1-NHERF2-ezrin-actin is a novel critical axis in the podocytes. Ephrin-B1 phosphorylation also disrupted the linkage of an apical transmembrane protein, podocalyxin, with NHERF2-ezrin-actin. The phosphorylation of ephrin-B1 and the consequent dephosphorylation of NHERF2 are critical initiation events leading to podocyte injury.
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Affiliation(s)
- Yoshiyasu Fukusumi
- Department of Cell Biology, Kidney Research Center, Niigata University Graduate School of Medical and Dental Sciences, Niigata, Japan
| | - Hidenori Yasuda
- Department of Cell Biology, Kidney Research Center, Niigata University Graduate School of Medical and Dental Sciences, Niigata, Japan
| | - Ying Zhang
- Department of Cell Biology, Kidney Research Center, Niigata University Graduate School of Medical and Dental Sciences, Niigata, Japan
| | - Hiroshi Kawachi
- Department of Cell Biology, Kidney Research Center, Niigata University Graduate School of Medical and Dental Sciences, Niigata, Japan.
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29
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Chin HJ, Chae DW, Kim YC, An WS, Ihm C, Jin DC, Kim SG, Kim YL, Kim YS, Kim YG, Koo HS, Lee JE, Lee KW, Oh J, Park JH, Jiang H, Lee H, Lee SK. Comparison of the Efficacy and Safety of Tacrolimus and Low-Dose Corticosteroid with High-Dose Corticosteroid for Minimal Change Nephrotic Syndrome in Adults. J Am Soc Nephrol 2021; 32:199-210. [PMID: 33168602 PMCID: PMC7894664 DOI: 10.1681/asn.2019050546] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2019] [Accepted: 09/08/2020] [Indexed: 02/04/2023] Open
Abstract
BACKGROUND Tacrolimus is used as a steroid-sparing immunosuppressant in adults with minimal change nephrotic syndrome. However, combined treatment with tacrolimus and low-dose steroid has not been compared with high-dose steroid for induction of clinical remission in a large-scale randomized study. METHODS In this 24-week open-label noninferiority study, we randomized 144 adults with minimal change nephrotic syndrome to receive 0.05 mg/kg twice-daily tacrolimus plus once-daily 0.5 mg/kg prednisolone, or once-daily 1 mg/kg prednisolone alone, for up to 8 weeks or until achieving complete remission. Two weeks after complete remission, we tapered the steroid to a maintenance dose of 5-7.5 mg/d in both groups until 24 weeks after study drug initiation. The primary end point was complete remission within 8 weeks (urine protein: creatinine ratio <0.2 g/g). Secondary end points included time until remission and relapse rates (proteinuria and urine protein: creatinine ratio >3.0 g/g) after complete remission to within 24 weeks of study drug initiation. RESULTS Complete remission within 8 weeks occurred in 53 of 67 patients (79.1%) receiving tacrolimus and low-dose steroid and 53 of 69 patients (76.8%) receiving high-dose steroid; this difference demonstrated noninferiority, with an upper confidence limit below the predefined threshold (20%) in both intent-to-treat (11.6%) and per-protocol (17.0%) analyses. Groups did not significantly differ in time until remission. Significantly fewer patients relapsed on maintenance tacrolimus (3-8 ng/ml) plus tapered steroid versus tapered steroid alone (5.7% versus 22.6%, respectively; P=0.01). There were no clinically relevant safety differences. CONCLUSIONS Combined tacrolimus and low-dose steroid was noninferior to high-dose steroid for complete remission induction in adults with minimal change nephrotic syndrome. Relapse rates were significantly lower with maintenance tacrolimus and steroid compared with steroid alone. No clinically-relevant differences in safety findings were observed.
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Affiliation(s)
- Ho Jun Chin
- Department of Internal Medicine, Seoul National University Bundang Hospital, Seongnam, South Korea,Department of Internal Medicine, Seoul National University College of Medicine, Seoul, South Korea
| | - Dong-Wan Chae
- Department of Internal Medicine, Seoul National University Bundang Hospital, Seongnam, South Korea
| | - Yong Chul Kim
- Department of Internal Medicine, Seoul National University Hospital, Seoul, South Korea
| | - Won Suk An
- Department of Internal Medicine, Dong-A University College of Medicine, Busan, South Korea
| | - ChunGyoo Ihm
- Department of Nephrology, Kyunghee University Medical Center, Seoul, South Korea
| | - Dong-Chan Jin
- Department of Internal Medicine, St Vincent Hospital, Suwon, South Korea
| | - Sung Gyun Kim
- Department of Internal Medicine, Hallym University Sacred Heart Hospital, Anyang, South Korea
| | - Yong-Lim Kim
- Department of Internal Medicine, School of Medicine, Kyungpook National University, Daegu, South Korea
| | - Yong-Soo Kim
- Department of Internal Medicine, The Catholic University of Korea, Seoul St. Mary’s Hospital, Seoul, South Korea
| | - Yoon-Goo Kim
- Department of Medicine, Samsung Medical Centre, Sungkyunkwan University School of Medicine, Seoul, South Korea
| | - Ho Seok Koo
- Department of Internal Medicine, Inje University Seoul Paik Hospital, Seoul, South Korea
| | - Jung Eun Lee
- Department of Medicine, Samsung Medical Centre, Sungkyunkwan University School of Medicine, Seoul, South Korea
| | - Kang Wook Lee
- Department of Nephrology, Chungnam National University Hospital, Daejeon, South Korea
| | - Jieun Oh
- Department of Internal Medicine, Kangdong Sacred Heart Hospital, Seoul, South Korea
| | - Jung Hwan Park
- Department of Internal Medicine, Konkuk University Medical Center, Seoul, South Korea
| | - Hongsi Jiang
- Medical Affairs Asia Oceania, Astellas Pharma Singapore Pte. Ltd., Singapore
| | - Hyuncheol Lee
- Clinical Research, Astellas Pharma Korea Inc., Seoul, South Korea
| | - Sang Koo Lee
- Department of Internal Medicine, Asan Medical Center, University of Ulsan, Seoul, South Korea
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30
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Lantman MVS, van de Logt AE, Thelen M, Wetzels JF, van Berkel M. Measurement of serum albumin in nephrology: we need to improve. Nephrol Dial Transplant 2020; 37:1792-1799. [PMID: 33367921 DOI: 10.1093/ndt/gfaa375] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2020] [Indexed: 11/14/2022] Open
Abstract
Serum albumin is a widely used biomarker in clinical nephrology. Serum albumin cut-off values are used to define disease, to predict outcome, and to guide patient care. The available commercial assays to measure serum albumin rely on different analytical principles, all with their own (analytical) specifications. This paper provides an overview of the different clinical applications of serum albumin measurements in nephrology, the (dis)advantages of the available assays and the estimates of the effects of the measurement uncertainty between different assays in clinical decision making. This paper concludes that harmonisation of serum albumin assay results are needed.
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Affiliation(s)
- Marith van Schrojenstein Lantman
- Radboud University Medical Centre, Department of Laboratory Medicine, Nijmegen, The Netherlands.,Amphia Hospital, Department of Laboratory for Clinical Chemistry, part of Result Laboratorium, Breda, The Netherlands.,SKML, Organisation for Quality Assurance of Medical Laboratory Diagnostics, Radboud University, Nijmegen, The Netherlands
| | - Anne-Els van de Logt
- Radboud University Medical Centre, Radboud Institute for Health Sciences, Department of Nephrology, Nijmegen, The Netherlands
| | - Marc Thelen
- Radboud University Medical Centre, Department of Laboratory Medicine, Nijmegen, The Netherlands.,Amphia Hospital, Department of Laboratory for Clinical Chemistry, part of Result Laboratorium, Breda, The Netherlands.,SKML, Organisation for Quality Assurance of Medical Laboratory Diagnostics, Radboud University, Nijmegen, The Netherlands
| | - Jack F Wetzels
- Radboud University Medical Centre, Radboud Institute for Health Sciences, Department of Nephrology, Nijmegen, The Netherlands
| | - Miranda van Berkel
- Radboud University Medical Centre, Department of Laboratory Medicine, Nijmegen, The Netherlands
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31
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Qin AB, Lin ZS, Wang SX, Wang H, Cui Z, Zhou FD, Zhao MH. Comparison of Ultrastructural Features Between Patients with Mercury-associated Membranous Nephropathy and Idiopathic Membranous Nephropathy. Am J Med Sci 2020; 361:327-335. [PMID: 33632518 DOI: 10.1016/j.amjms.2020.11.019] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2020] [Revised: 10/09/2020] [Accepted: 11/23/2020] [Indexed: 11/26/2022]
Abstract
BACKGROUND Prolonged exposure to mercury can cause membranous nephropathy. Mercury-associated membranous nephropathy (M-MN) and idiopathic membranous nephropathy (I-MN) have similar clinical manifestations, making misdiagnoses likely. We compared the clinicopathological and ultrastructural features of M-MN and I-MN. METHODS We retrospectively analyzed the clinicopathological data of 13 M-MN patients and 13 I-MN patients. Electron micrographs of glomerular capillaries were taken, and foot process width (FPW) and the number of foot processes per 10 μm glomerular basement membrane (GBM) were calculated. The presence and location of electron-dense deposits were recorded. RESULTS Compared with I-MN patients, M-MN patients were younger (38.7 ± 8.5 versus 45.8 ± 5.7 years, P = 0.020), achieved complete remission more quickly (9.0 ± 6.1 versus 20.3 ± 9.8 months, P = 0.004), and had a lower relapse rate (0 versus 45.5%, P = 0.014). Patients with M-MN also had lower FPW (974.3 [interquartile range or IQR, 791.2-1504.4] nm versus 2370.6 [IQR, 2219.4-2559.1] nm, P = 0.001), more foot processes per 10 μm GBM (8.1 [IQR, 5.2-10.0] versus 3.3 [IQR, 3.1-3.5], P = 0.001), and a higher rate of mesangial electron-dense deposits (41.7% versus 0, P = 0.015). A cut-off FPW of <1654 nm differentiated M-MN from I-MN with high sensitivity (92.3%) and specificity (83.3%). CONCLUSIONS Foot process effacement was less severe in M-MN than in I-MN. In patients with mercury toxic exposure, MN with less severe foot processes effacement suggested mercury could be the cause. Better prognosis in patients with M-MN may be associated with minor podocyte damage.
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Affiliation(s)
- Ai-Bo Qin
- Renal Division, Department of Medicine, Peking University First Hospital, Renal Pathology Center, Institute of Nephrology, Peking University, Key Laboratory of Renal Disease, Ministry of Health of China, Key Laboratory of CKD Prevention and Treatment, Ministry of Education of China, Research Units of Diagnosis and Treatment of Immune-mediated Kidney Diseases, Chinese Academy of Medical Sciences, Beijing, China
| | - Zi-Shan Lin
- Renal Division, Department of Medicine, Peking University First Hospital, Renal Pathology Center, Institute of Nephrology, Peking University, Key Laboratory of Renal Disease, Ministry of Health of China, Key Laboratory of CKD Prevention and Treatment, Ministry of Education of China, Research Units of Diagnosis and Treatment of Immune-mediated Kidney Diseases, Chinese Academy of Medical Sciences, Beijing, China
| | - Su-Xia Wang
- Renal Division, Department of Medicine, Peking University First Hospital, Renal Pathology Center, Institute of Nephrology, Peking University, Key Laboratory of Renal Disease, Ministry of Health of China, Key Laboratory of CKD Prevention and Treatment, Ministry of Education of China, Research Units of Diagnosis and Treatment of Immune-mediated Kidney Diseases, Chinese Academy of Medical Sciences, Beijing, China; Electron Microscopy Laboratory, Peking University First Hospital Beijing, China
| | - Hui Wang
- Renal Division, Department of Medicine, Peking University First Hospital, Renal Pathology Center, Institute of Nephrology, Peking University, Key Laboratory of Renal Disease, Ministry of Health of China, Key Laboratory of CKD Prevention and Treatment, Ministry of Education of China, Research Units of Diagnosis and Treatment of Immune-mediated Kidney Diseases, Chinese Academy of Medical Sciences, Beijing, China; Electron Microscopy Laboratory, Peking University First Hospital Beijing, China
| | - Zhao Cui
- Renal Division, Department of Medicine, Peking University First Hospital, Renal Pathology Center, Institute of Nephrology, Peking University, Key Laboratory of Renal Disease, Ministry of Health of China, Key Laboratory of CKD Prevention and Treatment, Ministry of Education of China, Research Units of Diagnosis and Treatment of Immune-mediated Kidney Diseases, Chinese Academy of Medical Sciences, Beijing, China
| | - Fu-de Zhou
- Renal Division, Department of Medicine, Peking University First Hospital, Renal Pathology Center, Institute of Nephrology, Peking University, Key Laboratory of Renal Disease, Ministry of Health of China, Key Laboratory of CKD Prevention and Treatment, Ministry of Education of China, Research Units of Diagnosis and Treatment of Immune-mediated Kidney Diseases, Chinese Academy of Medical Sciences, Beijing, China.
| | - Ming-Hui Zhao
- Renal Division, Department of Medicine, Peking University First Hospital, Renal Pathology Center, Institute of Nephrology, Peking University, Key Laboratory of Renal Disease, Ministry of Health of China, Key Laboratory of CKD Prevention and Treatment, Ministry of Education of China, Research Units of Diagnosis and Treatment of Immune-mediated Kidney Diseases, Chinese Academy of Medical Sciences, Beijing, China; Peking-Tsinghua Center for Life Sciences, Beijing, China
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da Silva CA, Monteiro MLGDR, Araújo LS, Urzedo MG, Rocha LB, dos Reis MA, Machado JR. In situ evaluation of podocytes in patients with focal segmental glomerulosclerosis and minimal change disease. PLoS One 2020; 15:e0241745. [PMID: 33147279 PMCID: PMC7641434 DOI: 10.1371/journal.pone.0241745] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2020] [Accepted: 10/21/2020] [Indexed: 12/18/2022] Open
Abstract
Podocyte injury in focal segmental glomerulosclerosis (FSGS) and minimal change disease (MCD) results from the imbalance between adaptive responses that maintain homeostasis and cellular dysfunction that can culminate in cell death. Therefore, an in situ analysis was performed to detect morphological changes related to cell death and autophagy in renal biopsies from adult patients with podocytopathies. Forty-nine renal biopsies from patients with FSGS (n = 22) and MCD (n = 27) were selected. In situ expression of Wilms Tumor 1 protein (WT1), light chain microtubule 1-associated protein (LC3) and caspase-3 protein were evaluated by immunohistochemistry. The foot process effacement and morphological alterations related to podocyte cell death and autophagy were analyzed with transmission electronic microscopy. Reduction in the density of WT1-labeled podocytes was observed for FSGS and MCD cases as compared to controls. Foot process width (FPW) in control group was lower than in cases of podocytopathies. In FSGS group, FPW was significantly higher than in MCD group and correlated with proteinuria. A density of LC3-labeled podocytes and the number of autophagosomes in podocytes/ pedicels were higher in the MCD group than in the FSGS group. The number of autophagosomes correlated positively with the estimated glomerular filtration rate in cases of MCD. The density of caspase-3-labeled podocytes in FSGS and MCD was higher than control group, and a higher number of podocytes with an evidence of necrosis was detected in FSGS cases than in MCD and control cases. Podocytes from patients diagnosed with FSGS showed more morphological and functional alterations resulting from a larger number of lesions and reduced cell adaptation.
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Affiliation(s)
- Crislaine Aparecida da Silva
- Department of Pathology, Genetics and Evolution, Discipline of General Pathology, Institute of Biological and Natural Sciences, Federal University of Triângulo Mineiro, Uberaba, Minas Gerais, Brazil
| | - Maria Luíza Gonçalves dos Reis Monteiro
- Department of Pathology, Genetics and Evolution, Discipline of General Pathology, Institute of Biological and Natural Sciences, Federal University of Triângulo Mineiro, Uberaba, Minas Gerais, Brazil
| | - Liliane Silvano Araújo
- Department of Pathology, Genetics and Evolution, Discipline of General Pathology, Institute of Biological and Natural Sciences, Federal University of Triângulo Mineiro, Uberaba, Minas Gerais, Brazil
| | - Monise Gini Urzedo
- Department of Pathology, Genetics and Evolution, Discipline of General Pathology, Institute of Biological and Natural Sciences, Federal University of Triângulo Mineiro, Uberaba, Minas Gerais, Brazil
| | - Lenaldo Branco Rocha
- Department of Pathology, Genetics and Evolution, Discipline of General Pathology, Institute of Biological and Natural Sciences, Federal University of Triângulo Mineiro, Uberaba, Minas Gerais, Brazil
| | - Marlene Antônia dos Reis
- Department of Pathology, Genetics and Evolution, Discipline of General Pathology, Institute of Biological and Natural Sciences, Federal University of Triângulo Mineiro, Uberaba, Minas Gerais, Brazil
| | - Juliana Reis Machado
- Department of Pathology, Genetics and Evolution, Discipline of General Pathology, Institute of Biological and Natural Sciences, Federal University of Triângulo Mineiro, Uberaba, Minas Gerais, Brazil
- * E-mail:
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Padala SA, Birkelo B, Mohammed A, Kapoor R, Mulloy L, Rawla P. Collapsing focal segmental sclerosis in an HIV-negative patient. Clin Case Rep 2020; 8:2166-2171. [PMID: 33235752 PMCID: PMC7669430 DOI: 10.1002/ccr3.3078] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2020] [Revised: 04/21/2020] [Accepted: 06/06/2020] [Indexed: 01/10/2023] Open
Abstract
Collapsing focal segmental glomerulosclerosis (FSGS) is classically seen in HIV-infected patients and carries a dismal prognosis. It can also occur in HIV-negative patients in which case, early aggressive treatment with glucocorticoids may be helpful with improvement in both proteinuria and renal function.
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Affiliation(s)
- Sandeep Anand Padala
- Department of Medicine, NephrologyMedical College of GeorgiaAugusta UniversityAugustaGAUSA
| | - Bethany Birkelo
- Department of MedicineMedical College of GeorgiaAugusta UniversityAugustaGAUSA
| | - Azeem Mohammed
- Department of Medicine, NephrologyMedical College of GeorgiaAugusta UniversityAugustaGAUSA
| | - Rajan Kapoor
- Department of Medicine, NephrologyMedical College of GeorgiaAugusta UniversityAugustaGAUSA
| | - Laura Mulloy
- Department of Medicine, NephrologyMedical College of GeorgiaAugusta UniversityAugustaGAUSA
| | - Prashanth Rawla
- Department of Internal MedicineSovah HealthMartinsvilleVAUSA
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Qin AB, Yu XJ, Wang SX, Zhou FD, Zhao MH. Unveiling the Features of Mercury-Associated Minimal Change Disease: Comparison with Primary Minimal Change Disease. KIDNEY DISEASES 2020; 7:156-165. [PMID: 33824871 DOI: 10.1159/000510877] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/09/2020] [Accepted: 08/10/2020] [Indexed: 11/19/2022]
Abstract
Introduction Long-term exposure to mercury can cause minimal change disease. However, the current understanding of mercury-associated minimal change disease (M-MCD) is inadequate. To improve the understanding of M-MCD, this study retrospectively analyzed the clinicopathological, ultrastructural, and prognostic features of M-MCD, in comparison with primary minimal change disease (P-MCD). Methods We retrospectively analyzed the clinicopathological data of 21 M-MCD patients and 21 P-MCD patients. Electron micrographs of glomerular capillaries were taken, and the foot process width (FPW) was measured. A receiver operating characteristics (ROC) curve analysis was performed to determine the optimum cutoff value of FPW that can differentiate the M-MCD from P-MCD. Results M-MCD patients presented similar clinical and routine pathological characteristics with P-MCD patients but had lower levels of FPW (935.0 [interquartile range (IQR) 853.7-1,176.7] nm vs. 1,403.2 [IQR 1,089.2-1,841.8] nm, p = 0.002). ROC curve analysis showed that FPW value below 1,385 nm might help to differentiate M-MCD from P-MCD (area under the curve of 0.787, sensitivity of 94.7%, and specificity of 52.4%). For patients with M-MCD, 77.8% achieved complete remission after mercury detoxification monotherapy. Patients with M-MCD had a lower relapse rate than patients with P-MCD (0 vs. 47.1%, p = 0.003). In addition, there was no significant difference in remission time between M-MCD patients treated with mercury detoxification monotherapy and those initially treated with immunosuppressive therapy (2.0 [IQR 1.0-6.0] months vs. 2.0 [IQR 1.5-2.5] months, p = 0.606). Conclusions M-MCD patients showed similar clinicopathological features with P-MCD patients, but with less severe foot process effacement, suggesting different pathogenesis of these 2 disease entities. The treatment of mercury detoxification was highly effective for patients with M-MCD and can be considered as a primary choice in clinical practice.
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Affiliation(s)
- Ai-Bo Qin
- Renal Division, Department of Medicine, Peking University First Hospital, Beijing, China.,Institute of Nephrology, Peking University, Beijing, China.,Key Laboratory of Renal Disease, Ministry of Health of China, Beijing, China.,Key Laboratory of CKD Prevention and Treatment, Ministry of Education of China, Beijing, China.,Research Units of Diagnosis and Treatment of Immune-mediated Kidney Diseases, Chinese Academy of Medical Sciences, Beijing, China
| | - Xiao-Juan Yu
- Renal Division, Department of Medicine, Peking University First Hospital, Beijing, China.,Institute of Nephrology, Peking University, Beijing, China.,Key Laboratory of Renal Disease, Ministry of Health of China, Beijing, China.,Key Laboratory of CKD Prevention and Treatment, Ministry of Education of China, Beijing, China.,Research Units of Diagnosis and Treatment of Immune-mediated Kidney Diseases, Chinese Academy of Medical Sciences, Beijing, China
| | - Su-Xia Wang
- Renal Division, Department of Medicine, Peking University First Hospital, Beijing, China.,Institute of Nephrology, Peking University, Beijing, China.,Key Laboratory of Renal Disease, Ministry of Health of China, Beijing, China.,Key Laboratory of CKD Prevention and Treatment, Ministry of Education of China, Beijing, China.,Research Units of Diagnosis and Treatment of Immune-mediated Kidney Diseases, Chinese Academy of Medical Sciences, Beijing, China.,Electron Microscopy Laboratory, Pathological Center, Peking University First Hospital, Beijing, China
| | - Fu-de Zhou
- Renal Division, Department of Medicine, Peking University First Hospital, Beijing, China.,Institute of Nephrology, Peking University, Beijing, China.,Key Laboratory of Renal Disease, Ministry of Health of China, Beijing, China.,Key Laboratory of CKD Prevention and Treatment, Ministry of Education of China, Beijing, China.,Research Units of Diagnosis and Treatment of Immune-mediated Kidney Diseases, Chinese Academy of Medical Sciences, Beijing, China
| | - Ming-Hui Zhao
- Renal Division, Department of Medicine, Peking University First Hospital, Beijing, China.,Institute of Nephrology, Peking University, Beijing, China.,Key Laboratory of Renal Disease, Ministry of Health of China, Beijing, China.,Key Laboratory of CKD Prevention and Treatment, Ministry of Education of China, Beijing, China.,Research Units of Diagnosis and Treatment of Immune-mediated Kidney Diseases, Chinese Academy of Medical Sciences, Beijing, China.,Peking-Tsinghua Center for Life Sciences, Beijing, China
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Hu YF, Tan Y, Yu XJ, Wang H, Wang SX, Yu F, Zhao MH. Podocyte Involvement in Renal Thrombotic Microangiopathy: A Clinicopathological Study. Am J Nephrol 2020; 51:752-760. [PMID: 32862175 DOI: 10.1159/000510141] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2020] [Accepted: 07/14/2020] [Indexed: 12/14/2022]
Abstract
BACKGROUND The current study aimed to evaluate the associations between podocyte injury and clinicopathological features in renal thrombotic microangiopathy (TMA) based on a Chinese cohort, which might be underscored in this disease. METHODS The clinical, laboratory, and renal histopathological data of patients with renal biopsy-proven TMA from 2000 to 2015 in our institute were collected. Foot process effacement (FPE) was quantified by foot process width (FPW) by electron microscopy. Podocytes in the renal specimens were also detected by stainings for podocyte-specific markers, including Wilms tumor 1 (WT-1), synaptopodin, and podocalyxin. The associations between FPW and clinico-histopathological data were further analyzed. A composite end-point was defined by all-cause death or end-stage renal disease to address the predictive value of FPW. RESULTS Sixty-three patients with renal biopsy-proven TMA were enrolled. The FPW of renal TMA patients was 1,090 ± 637 nm (range, 572-4,748 nm), which was significantly higher than the normal range in our center (p = 0.005). By immunohistochemistry and immunofluorescence assays, we found decreased expressions of synaptopodin, podocalyxin, and WT-1 and continued stainings of WT-1 in some podocytes without detectable synaptopodin stainings in the areas of sclerotic tufts and cellular crescents. The FPW value was correlated with the serum albumin concentration (rs = -0.281, p = 0.026), proteinuria amount (rs = 0.255, p = 0.047), serum creatinine levels (rs = 0.339, p = 0.007), and eGFR (rs = -0.335, p = 0.007). According to ROC curve analysis, the optimal cutoff level of FPW for predicting the composite end-point was 869 nm. In patients with FPW ≥ 869 nm, FPW levels were further correlated with the severity of mesangiolysis (rs = 0.351, p = 0.033) and glomerulosclerosis (rs = 0.369, p = 0.025) in pathological evaluations. Patients without clinical remission also had higher FPW than those with remission (1,240 ± 793 vs. 925 ± 344 nm, p = 0.013). The multivariate Cox hazard model showed that FPW ≥ 869 nm was an independent risk factor for the composite end-point (hazard ratio: 3.64, 95% CI: 1.37-9.66, p = 0.009). CONCLUSION The podocyte injury was prevalent and the FPW levels were closely associated with clinicopathological features, especially prognosis, in renal TMA patients.
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Affiliation(s)
- Yi-Fang Hu
- Renal Division, Department of Medicine, Peking University First Hospital, Beijing, China
- Institute of Nephrology, Peking University, Beijing, China
- Key Laboratory of Renal Disease, Ministry of Health of China, Beijing, China
- Key Laboratory of CKD Prevention and Treatment, Ministry of Education of China, Beijing, China
- Research Units of Diagnosis and Treatment of Immune-Mediated Kidney Diseases, Chinese Academy of Medical Sciences, Beijing, China
| | - Ying Tan
- Renal Division, Department of Medicine, Peking University First Hospital, Beijing, China
- Institute of Nephrology, Peking University, Beijing, China
- Key Laboratory of Renal Disease, Ministry of Health of China, Beijing, China
- Key Laboratory of CKD Prevention and Treatment, Ministry of Education of China, Beijing, China
- Research Units of Diagnosis and Treatment of Immune-Mediated Kidney Diseases, Chinese Academy of Medical Sciences, Beijing, China
| | - Xiao-Juan Yu
- Renal Division, Department of Medicine, Peking University First Hospital, Beijing, China
- Institute of Nephrology, Peking University, Beijing, China
- Key Laboratory of Renal Disease, Ministry of Health of China, Beijing, China
- Key Laboratory of CKD Prevention and Treatment, Ministry of Education of China, Beijing, China
- Research Units of Diagnosis and Treatment of Immune-Mediated Kidney Diseases, Chinese Academy of Medical Sciences, Beijing, China
| | - Hui Wang
- Renal Division, Department of Medicine, Peking University First Hospital, Beijing, China
- Institute of Nephrology, Peking University, Beijing, China
- Key Laboratory of Renal Disease, Ministry of Health of China, Beijing, China
- Key Laboratory of CKD Prevention and Treatment, Ministry of Education of China, Beijing, China
- Research Units of Diagnosis and Treatment of Immune-Mediated Kidney Diseases, Chinese Academy of Medical Sciences, Beijing, China
- Department of Electron Microscopy, Peking University First Hospital, Beijing, China
| | - Su-Xia Wang
- Renal Division, Department of Medicine, Peking University First Hospital, Beijing, China
- Institute of Nephrology, Peking University, Beijing, China
- Key Laboratory of Renal Disease, Ministry of Health of China, Beijing, China
- Key Laboratory of CKD Prevention and Treatment, Ministry of Education of China, Beijing, China
- Research Units of Diagnosis and Treatment of Immune-Mediated Kidney Diseases, Chinese Academy of Medical Sciences, Beijing, China
- Department of Electron Microscopy, Peking University First Hospital, Beijing, China
| | - Feng Yu
- Renal Division, Department of Medicine, Peking University First Hospital, Beijing, China,
- Institute of Nephrology, Peking University, Beijing, China,
- Key Laboratory of Renal Disease, Ministry of Health of China, Beijing, China,
- Key Laboratory of CKD Prevention and Treatment, Ministry of Education of China, Beijing, China,
- Research Units of Diagnosis and Treatment of Immune-Mediated Kidney Diseases, Chinese Academy of Medical Sciences, Beijing, China,
- Department of Nephrology, Peking University International Hospital, Beijing, China,
| | - Ming-Hui Zhao
- Renal Division, Department of Medicine, Peking University First Hospital, Beijing, China
- Institute of Nephrology, Peking University, Beijing, China
- Key Laboratory of Renal Disease, Ministry of Health of China, Beijing, China
- Key Laboratory of CKD Prevention and Treatment, Ministry of Education of China, Beijing, China
- Research Units of Diagnosis and Treatment of Immune-Mediated Kidney Diseases, Chinese Academy of Medical Sciences, Beijing, China
- Peking-Tsinghua Center for Life Sciences, Beijing, China
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Abstract
Podocytopathies are kidney diseases in which direct or indirect podocyte injury drives proteinuria or nephrotic syndrome. In children and young adults, genetic variants in >50 podocyte-expressed genes, syndromal non-podocyte-specific genes and phenocopies with other underlying genetic abnormalities cause podocytopathies associated with steroid-resistant nephrotic syndrome or severe proteinuria. A variety of genetic variants likely contribute to disease development. Among genes with non-Mendelian inheritance, variants in APOL1 have the largest effect size. In addition to genetic variants, environmental triggers such as immune-related, infection-related, toxic and haemodynamic factors and obesity are also important causes of podocyte injury and frequently combine to cause various degrees of proteinuria in children and adults. Typical manifestations on kidney biopsy are minimal change lesions and focal segmental glomerulosclerosis lesions. Standard treatment for primary podocytopathies manifesting with focal segmental glomerulosclerosis lesions includes glucocorticoids and other immunosuppressive drugs; individuals not responding with a resolution of proteinuria have a poor renal prognosis. Renin-angiotensin system antagonists help to control proteinuria and slow the progression of fibrosis. Symptomatic management may include the use of diuretics, statins, infection prophylaxis and anticoagulation. This Primer discusses a shift in paradigm from patient stratification based on kidney biopsy findings towards personalized management based on clinical, morphological and genetic data as well as pathophysiological understanding.
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Pisarek-Horowitz A, Fan X, Kumar S, Rasouly HM, Sharma R, Chen H, Coser K, Bluette CT, Hirenallur-Shanthappa D, Anderson SR, Yang H, Beck LH, Bonegio RG, Henderson JM, Berasi SP, Salant DJ, Lu W. Loss of Roundabout Guidance Receptor 2 (Robo2) in Podocytes Protects Adult Mice from Glomerular Injury by Maintaining Podocyte Foot Process Structure. THE AMERICAN JOURNAL OF PATHOLOGY 2020; 190:799-816. [PMID: 32220420 PMCID: PMC7217334 DOI: 10.1016/j.ajpath.2019.12.009] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/16/2019] [Revised: 11/24/2019] [Accepted: 12/17/2019] [Indexed: 02/06/2023]
Abstract
Roundabout guidance receptor 2 (ROBO2) plays an important role during early kidney development. ROBO2 is expressed in podocytes, inhibits nephrin-induced actin polymerization, down-regulates nonmuscle myosin IIA activity, and destabilizes kidney podocyte adhesion. However, the role of ROBO2 during kidney injury, particularly in mature podocytes, is not known. Herein, we report that loss of ROBO2 in podocytes [Robo2 conditional knockout (cKO) mouse] is protective from glomerular injuries. Ultrastructural analysis reveals that Robo2 cKO mice display less foot process effacement and better-preserved slit-diaphragm density compared with wild-type littermates injured by either protamine sulfate or nephrotoxic serum (NTS). The Robo2 cKO mice also develop less proteinuria after NTS injury. Further studies reveal that ROBO2 expression in podocytes is up-regulated after glomerular injury because its expression levels are higher in the glomeruli of NTS injured mice and passive Heymann membranous nephropathy rats. Moreover, the amount of ROBO2 in the glomeruli is also elevated in patients with membranous nephropathy. Finally, overexpression of ROBO2 in cultured mouse podocytes compromises cell adhesion. Taken together, these findings suggest that kidney injury increases glomerular ROBO2 expression that might compromise podocyte adhesion and, thus, loss of Robo2 in podocytes could protect from glomerular injury by enhancing podocyte adhesion that helps maintain foot process structure. Our findings also suggest that ROBO2 is a therapeutic target for podocyte injury and podocytopathy.
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Affiliation(s)
- Anna Pisarek-Horowitz
- Renal Section, Department of Medicine, Boston University School of Medicine, Boston Medical Center, Boston, Massachusetts
| | - Xueping Fan
- Renal Section, Department of Medicine, Boston University School of Medicine, Boston Medical Center, Boston, Massachusetts
| | - Sudhir Kumar
- Renal Section, Department of Medicine, Boston University School of Medicine, Boston Medical Center, Boston, Massachusetts
| | - Hila M Rasouly
- Renal Section, Department of Medicine, Boston University School of Medicine, Boston Medical Center, Boston, Massachusetts
| | - Richa Sharma
- Renal Section, Department of Medicine, Boston University School of Medicine, Boston Medical Center, Boston, Massachusetts
| | - Hui Chen
- Department of Pathology and Laboratory Medicine, Boston University School of Medicine, Boston Medical Center, Boston, Massachusetts
| | - Kathryn Coser
- Centers for Therapeutic Innovation, Pfizer Inc., Cambridge, Massachusetts
| | | | | | - Sarah R Anderson
- Global Pathology, Drug Safety Research and Development, Pfizer Inc., Groton, Connecticut
| | - Hongying Yang
- Centers for Therapeutic Innovation, Pfizer Inc., Cambridge, Massachusetts
| | - Laurence H Beck
- Renal Section, Department of Medicine, Boston University School of Medicine, Boston Medical Center, Boston, Massachusetts
| | - Ramon G Bonegio
- Renal Section, Department of Medicine, Boston University School of Medicine, Boston Medical Center, Boston, Massachusetts
| | - Joel M Henderson
- Department of Pathology and Laboratory Medicine, Boston University School of Medicine, Boston Medical Center, Boston, Massachusetts
| | - Stephen P Berasi
- Centers for Therapeutic Innovation, Pfizer Inc., Cambridge, Massachusetts
| | - David J Salant
- Renal Section, Department of Medicine, Boston University School of Medicine, Boston Medical Center, Boston, Massachusetts; Department of Pathology and Laboratory Medicine, Boston University School of Medicine, Boston Medical Center, Boston, Massachusetts
| | - Weining Lu
- Renal Section, Department of Medicine, Boston University School of Medicine, Boston Medical Center, Boston, Massachusetts; Department of Pathology and Laboratory Medicine, Boston University School of Medicine, Boston Medical Center, Boston, Massachusetts.
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Royal V, Zee J, Liu Q, Avila-Casado C, Smith AR, Liu G, Mariani LH, Hewitt S, Holzman LB, Gillespie BW, Hodgin JB, Barisoni L. Ultrastructural Characterization of Proteinuric Patients Predicts Clinical Outcomes. J Am Soc Nephrol 2020; 31:841-854. [PMID: 32086276 DOI: 10.1681/asn.2019080825] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2019] [Accepted: 12/31/2019] [Indexed: 12/12/2022] Open
Abstract
BACKGROUND The analysis and reporting of glomerular features ascertained by electron microscopy are limited to few parameters with minimal predictive value, despite some contributions to disease diagnoses. METHODS We investigated the prognostic value of 12 electron microscopy histologic and ultrastructural changes (descriptors) from the Nephrotic Syndrome Study Network (NEPTUNE) Digital Pathology Scoring System. Study pathologists scored 12 descriptors in NEPTUNE renal biopsies from 242 patients with minimal change disease or FSGS, with duplicate readings to evaluate reproducibility. We performed consensus clustering of patients to identify unique electron microscopy profiles. For both individual descriptors and clusters, we used Cox regression models to assess associations with time from biopsy to proteinuria remission and time to a composite progression outcome (≥40% decline in eGFR, with eGFR<60 ml/min per 1.73 m2, or ESKD), and linear mixed models for longitudinal eGFR measures. RESULTS Intrarater and interrater reproducibility was >0.60 for 12 out of 12 and seven out of 12 descriptors, respectively. Individual podocyte descriptors such as effacement and microvillous transformation were associated with complete remission, whereas endothelial cell and glomerular basement membrane abnormalities were associated with progression. We identified six descriptor-based clusters with distinct electron microscopy profiles and clinical outcomes. Patients in a cluster with more prominent foot process effacement and microvillous transformation had the highest rates of complete proteinuria remission, whereas patients in clusters with extensive loss of primary processes and endothelial cell damage had the highest rates of the composite progression outcome. CONCLUSIONS Systematic analysis of electron microscopic findings reveals clusters of findings associated with either proteinuria remission or disease progression.
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Affiliation(s)
- Virginie Royal
- Department of Pathology, Hôpital Maisonneuve-Rosemont, Université de Montréal, Montréal, Québec, Canada;
| | - Jarcy Zee
- Arbor Research Collaborative for Health, Ann Arbor, Michigan
| | - Qian Liu
- Arbor Research Collaborative for Health, Ann Arbor, Michigan
| | - Carmen Avila-Casado
- Department of Laboratory Medicine, University of Toronto, Scarborough, Ontario, Canada
| | - Abigail R Smith
- Arbor Research Collaborative for Health, Ann Arbor, Michigan
| | - Gang Liu
- Arbor Research Collaborative for Health, Ann Arbor, Michigan
| | - Laura H Mariani
- Division of Nephrology, Department of Internal Medicine, University of Michigan, Ann Arbor, Michigan
| | - Stephen Hewitt
- Laboratory of Pathology, National Cancer Institute, National Institutes of Health, Bethesda, Maryland
| | - Lawrence B Holzman
- Renal-Electrolyte and Hypertension Division, Department of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Brenda W Gillespie
- Department of Biostatistics, University of Michigan, Ann Arbor, Michigan
| | - Jeffrey B Hodgin
- Renal Pathology, Department of Pathology, University of Michigan, Ann Arbor, Michigan
| | - Laura Barisoni
- Department of Pathology, Duke University, Durham, North Carolina
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Canney AL, Cohen RV, Elliott JA, M Aboud C, Martin WP, Docherty NG, le Roux CW. Improvements in diabetic albuminuria and podocyte differentiation following Roux-en-Y gastric bypass surgery. Diab Vasc Dis Res 2020; 17:1479164119879039. [PMID: 31726864 PMCID: PMC7510366 DOI: 10.1177/1479164119879039] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
BACKGROUND Multiple studies demonstrate an albuminuria-lowering impact of Roux-en-Y gastric bypass surgery, but neither evaluation of its penetrance across different baseline levels of albuminuria nor its association with alterations in podocyte phenotype has previously been reported. METHODS We profiled changes in body weight, glycaemic control and urinary albumin excretion following Roux-en-Y gastric bypass surgery in 105 patients with type 2 diabetes, albuminuria of varying degrees of severity and classified as being at moderate or high risk of chronic kidney disease progression according to the Kidney Disease: Improving Global Outcomes 2012 criteria. In parallel pre-clinical studies, the impact of Roux-en-Y gastric bypass surgery on markers of podocyte injury was assessed in the Zucker diabetic fatty rat model of diabetic kidney disease. RESULTS At 12- to 18-month post-operative follow-up in patients at moderate or high risk of chronic kidney disease, significant reductions in albuminuria were observed across all tertiles of baseline albumin-creatinine ratio, with remission of albuminuria occurring in 78% of patients. Relative to sham-operated control animals, weight loss and improvements in glycaemia following Roux-en-Y gastric bypass surgery in Zucker diabetic fatty rats were paralleled by normalisation of glomerular tuft-size, reductions in podocyte expression of desmin, and preservation of podocyte foot process morphology. CONCLUSION Improvements in podocyte differentiation likely underpin the reductions in albuminuria observed following Roux-en-Y gastric bypass surgery.
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Affiliation(s)
- Aoife L Canney
- UCD Diabetes Complications Research Centre, UCD Conway Institute, School of Medicine, University College Dublin, Dublin, Ireland
- Division of Anatomic Pathology, Department of Histopathology, Cytopathology and Molecular Pathology, University Hospital Galway, Galway, Ireland
| | - Ricardo V Cohen
- The Centre for Obesity and Diabetes, Oswaldo Cruz German Hospital, São Paulo, Brazil
| | - Jessie A Elliott
- UCD Diabetes Complications Research Centre, UCD Conway Institute, School of Medicine, University College Dublin, Dublin, Ireland
| | - Cristina M Aboud
- The Centre for Obesity and Diabetes, Oswaldo Cruz German Hospital, São Paulo, Brazil
| | - William P Martin
- UCD Diabetes Complications Research Centre, UCD Conway Institute, School of Medicine, University College Dublin, Dublin, Ireland
| | - Neil G Docherty
- UCD Diabetes Complications Research Centre, UCD Conway Institute, School of Medicine, University College Dublin, Dublin, Ireland
- Neil G Docherty, Diabetes Complications Research Centre, UCD Conway Institute, School of Medicine, University College Dublin, Dublin 4, Ireland.
| | - Carel W le Roux
- UCD Diabetes Complications Research Centre, UCD Conway Institute, School of Medicine, University College Dublin, Dublin, Ireland
- Investigative Science, Imperial College London, London, UK
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Hasbal NB, Caglayan FB, Sakaci T, Ahbap E, Koc Y, Sevinc M, Ucar ZA, Unsal A, Basturk T. Unexpectedly High Prevalence of Low Alpha-Galactosidase A Enzyme Activity in Patients with Focal Segmental Glomerulosclerosis. Clinics (Sao Paulo) 2020; 75:e1811. [PMID: 32997080 PMCID: PMC7510945 DOI: 10.6061/clinics/2020/e1811] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/11/2020] [Accepted: 06/02/2020] [Indexed: 11/18/2022] Open
Abstract
OBJECTIVES Fabry disease (FD) is a rare disease associated with sphingolipid accumulation. Sphingolipids are components of plasma membranes that are important in podocyte function and accumulate in various glomerular diseases such as focal segmental glomerulosclerosis (FSGS). Both FD and FSGS can cause podocyte damage and are classified as podocytopathies. In this respect, FD and FSGS share the same pathophysiologic pathways. Previous screening studies have shown that a significant proportion of end-stage renal disease (ESRD) patients receiving hemodialysis (HD) have unsuspected FD, and the prevalence of low alpha-galactosidase A (αGLA) enzyme activity in these patients is higher than that in the normal population. We aimed to compare αGLA enzyme activity in patients with biopsy-proven FSGS and ESRD receiving HD. METHODS The records of 232 patients [62 FSGS (F/M: 33/29); 170 HD (M/F: 93/79)] were evaluated retrospectively. The screening was performed based on the αGLA enzyme activity on a dried blood spot, with the confirmation of plasma LysoGb3 levels, and the known GLA mutations were tested in patients with low enzyme activities. The two groups were compared using these parameters. RESULTS The mean level of αGLA enzyme activity was found to be lower in FSGS patients than in the HD group (2.88±1.2 μmol/L/h versus 3.79±1.9 μmol/L/h, p<0.001). There was no significant relationship between the two groups with regard to the plasma LysoGb3 levels (2.2±1.22 ng/ml versus 1.7±0.66 ng/ml, p: 0.4). In the analysis of GLA mutations, a D313Y mutation [C(937G>T) in exon p] was found in one patient from the FSGS group. CONCLUSIONS We found that αGAL activity in patients with FSGS is lower than that in patients undergoing HD. The low enzyme activity in patients with FSGS may be explained by considering the similar pathogenesis of FSGS and FD, which may also lead to sphingolipid deposition and podocyte injury.
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Affiliation(s)
| | | | - Tamer Sakaci
- Department of Nephrology, Sisli Hamidiye Etfal Training and Research Hospital, Istanbul, Turkey
| | - Elbis Ahbap
- Department of Nephrology, Sisli Hamidiye Etfal Training and Research Hospital, Istanbul, Turkey
- Corresponding author. E-mail:
| | - Yener Koc
- Division of Nephrology, Department of Internal Medicine, Medical Faculty, Cumhuriyet University, Sivas, Turkey
| | - Mustafa Sevinc
- Department of Nephrology, Sisli Hamidiye Etfal Training and Research Hospital, Istanbul, Turkey
| | - Zuhal Atan Ucar
- Division of Nephrology, Department of Internal Medicine, Medical Faculty, Demiroglu Bilim University, Istanbul, Turkey
| | - Abdulkadir Unsal
- Department of Nephrology, Sisli Hamidiye Etfal Training and Research Hospital, Istanbul, Turkey
- Department of Internal Medicine, Faculty of Medicine, Health Sciences University, Istanbul, Turkey
| | - Taner Basturk
- Department of Nephrology, Sisli Hamidiye Etfal Training and Research Hospital, Istanbul, Turkey
- Department of Internal Medicine, Faculty of Medicine, Health Sciences University, Istanbul, Turkey
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Mühldorfer J, Pfister E, Büttner-Herold M, Klewer M, Amann K, Daniel C. Bi-nucleation of podocytes is uniformly accompanied by foot processes widening in renal disease. Nephrol Dial Transplant 2019; 33:796-803. [PMID: 29106627 DOI: 10.1093/ndt/gfx201] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2017] [Accepted: 04/28/2017] [Indexed: 01/13/2023] Open
Abstract
Background Podocytes are terminally differentiated glomerular cells expressing a highly complex architecture and lacking the ability to proliferate. However, during renal injury or stress these cells can re-enter into the cell cycle but fail to divide. As a consequence, bi- and multi-nucleated podocytes can be identified in renal biopsies from patients with various kidney diseases. It is still unclear whether the occurrence of such cells is dependent on or correlates with renal damage and if bi- or multi-nucleation results in ultrastructural alterations such as e.g. foot process effacement. Therefore, we investigated the frequency, correlation with clinical parameters and morphological consequences of podocyte bi- or multi-nucleation in a cohort of 377 patients suffering from different renal diseases. Methods Renal biopsies from patients with minimal change disease (MCD; n = 93), IgA-glomerulonephritis (IgA-GN, n = 95), lupus nephritis (LN; n = 90) and diabetic nephropathy (DN; n = 99) were investigated for the occurrence of bi-nucleated or multi-nucleated podocytes using semi-thin sections and light-microscopy at 1000× magnification. The frequency of bi-nucleation and multi-nucleation in podocytes was correlated with clinical parameters and markers of renal injury. In addition, ultrastructural morphological features associated with podocyte bi- or multi-nucleation were analysed by scanning transmission electron microscopy at various magnifications. Results Ultrastructural analysis of podocyte nuclear morphology revealed a broad spectrum of nuclear appearances. Therefore, podocytes were classified in cells with mono-nucleated, lobulated, potential bi-nucleated, symmetrically bi-nucleated, asymmetrically bi-nucleated and multi-nucleated nuclear morphology. In 65-80% of all investigated glomeruli only mono-nuclear podocytes were identified. The highest frequency of bi-nucleated podocytes was found in patients with IgA-GN (18.6%) and the lowest in patients with DN (5.6%). The proportion of bi-nucleated podocytes with asymmetric nuclear morphology was about 50% of all bi-nucleated podocytes and independent of the underlying renal disease. In addition, ultrastructural analysis by electron microscopy showed significant widening of foot processes in bi-nucleated compared with mono-nucleated podocytes. Interestingly, foot process width of podocytes with lobulated nuclei was also significantly increased compared with podocytes with normal mono-nuclear morphology. Furthermore, podocyte density per glomerular area was significantly lower in glomeruli with bi-nucleated podocytes. Due to the relatively low frequency of bi- and multi-nucleated podocytes, correlations with clinical parameters were weak and dependent on renal disease. Conclusions The frequency of bi-nucleated podocytes was highest in IgA-GN but can also be observed in all investigated renal diseases. In podocytes with altered nuclear morphology particularly in bi- and multi-nucleated podocytes ultrastructural analysis of podocytes revealed significant widening of foot processes as a potential maladaptive structural consequence.
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Affiliation(s)
- Johanna Mühldorfer
- Department of Nephropathology, Friedrich-Alexander University (FAU) Erlangen-Nürnberg, Erlangen, Germany
| | - Eva Pfister
- Department of Nephropathology, Friedrich-Alexander University (FAU) Erlangen-Nürnberg, Erlangen, Germany
| | - Maike Büttner-Herold
- Department of Nephropathology, Friedrich-Alexander University (FAU) Erlangen-Nürnberg, Erlangen, Germany
| | - Monika Klewer
- Department of Nephropathology, Friedrich-Alexander University (FAU) Erlangen-Nürnberg, Erlangen, Germany
| | - Kerstin Amann
- Department of Nephropathology, Friedrich-Alexander University (FAU) Erlangen-Nürnberg, Erlangen, Germany
| | - Christoph Daniel
- Department of Nephropathology, Friedrich-Alexander University (FAU) Erlangen-Nürnberg, Erlangen, Germany
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May CJ, Welsh GI, Chesor M, Lait PJ, Schewitz-Bowers LP, Lee RWJ, Saleem MA. Human Th17 cells produce a soluble mediator that increases podocyte motility via signaling pathways that mimic PAR-1 activation. Am J Physiol Renal Physiol 2019; 317:F913-F921. [PMID: 31339775 DOI: 10.1152/ajprenal.00093.2019] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The specific pathogenesis of idiopathic nephrotic syndrome (NS) is poorly understood, and the role of immune mediators remains contentious. However, there is good evidence for the role of a circulating factor, and we recently postulated circulating proteases as candidate factors. Immunosuppressive therapy with glucocorticoids (GCs) and T cell inhibitors are widely used in the clinical treatment of NS. Given that T helper (CD4+) cells expressing IL-17A (so-called Th17 cells) have recently been reported to be resistant to GC treatment, and GC resistance remains a major challenge in the management of NS, we hypothesized that Th17 cells produce a circulating factor that is capable of signaling to the podocyte and inducing deleterious phenotypic changes. To test this, we generated human Th17 cells from healthy volunteers and added the supernatants from these T cell cultures to conditionally immortalized human podocytes in vitro. This demonstrated that podocytes treated with Th17 cell culture supernatant, as well as with patient disease plasma, showed significant stimulation of JNK and p38 MAPK pathways and an increase in motility, which was blocked using a JNK inhibitor. We have previously shown that nephrotic plasma elicits a podocyte response via protease-activated receptor-1 (PAR-1). Stimulation of PAR-1 in podocytes elicited the same signaling response as Th17 cell culture supernatant treatment. Equally, protease inhibitors with Th17 cell culture treatment blocked the signaling response. This was not replicated by the reagents added to Th17 cell cultures or by IL-17A. Hence, we conclude that an undefined soluble mediator produced by Th17 cells mimics the deleterious effect of PAR-1 activation in vitro. Given the association between pathogenic subsets of Th17 cells and GC resistance, these observations have potential therapeutic relevance for patients with NS.
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Affiliation(s)
- Carl J May
- Bristol Renal, University of Bristol, Bristol, United Kingdom
| | - Gavin I Welsh
- Bristol Renal, University of Bristol, Bristol, United Kingdom
| | - Musleeha Chesor
- Bristol Renal, University of Bristol, Bristol, United Kingdom
| | - Phillipa J Lait
- Translational Health Sciences, Bristol Medical School, University of Bristol, Bristol, United Kingdom
| | - Lauren P Schewitz-Bowers
- Translational Health Sciences, Bristol Medical School, University of Bristol, Bristol, United Kingdom
| | - Richard W J Lee
- Translational Health Sciences, Bristol Medical School, University of Bristol, Bristol, United Kingdom
| | - Moin A Saleem
- Bristol Renal, University of Bristol, Bristol, United Kingdom
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Sipovsky VG, Nevorotin AI, Avsiewitsch IV, Smirnov AV. [Ultrastructural study of podocyte alterations in non proliferative glomerulopathy]. Arkh Patol 2019; 81:51-58. [PMID: 31317931 DOI: 10.17116/patol20198103151] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Ultrastructural changes in podocytes are an important diagnostic and prognostic marker for nephropathies. However, the biomedical understanding of detected submicroscopic changes in podocytes remains controversial. OBJECTIVE To investigate the relationship between the ultrastructural changes of podocytes (fusion of cytopodia and denudation of the basement membrane as a result of their desquamation) with a number of clinical and laboratory indicators of kidney dysfunction in case of non-proliferative glomerulopathies (NPGP). Thirty-seven patients (23 men, 14 women) with NPGP, including 8 with focal segmental glomerulosclerosis (FSGS), 17 with membranous nephropathy (MN), and 12 with minimal change disease (MCD), were examined. SUBJECT AND METHODS All the patients underwent standard laboratory and instrumental studies: determinations of the levels of total serum cholesterol (mmol/l), total serum protein (g/l); serum albumin (g/l); CKD-EPI glomerular filtration rate (GFR) (ml/min/1.73 m2), and daily protein loss (g/day). Light optical changes were measured; completely sclerotic and/or focally segmentally sclerotic glomeruli were taken into account. Quantitative ultrastructural stereological analysis was carried out estimating the cytopodium width (CPW) and the degree of glomerular basement membrane denudation (GBMD) (%). RESULTS NPGP cases showed the largest number of sclerotic glomeruli in FSGS, which was accompanied by the lowest level of daily proteinuria and GFR. Quantitative values of CPW were associated with the level of daily protein loss (r=0.47; p < 0.05) and serum albumin (r=-0.57; p <0.05) in patients with nephrotic syndrome. In MN, the absolute value of CPW was larger than that in the other two patient groups. A correlation analysis of CPW and GBMD values among patients with NPGP revealed a statistically insignificant negative relation between these morphometric parameters. However, when a subgroup of patients with podocytopathies (only MCD and FSGS) was identified in the study group, this relationship was found to be significant (r=-0.54; p=0.012). CONCLUSION The patients with NPGP exhibited a relationship between the severity of nephrotic syndrome and proteinuria/hypoalbuminemia, on the one hand, and CPW, on the other. The established negative relationship between CPW and the percentage of GBMD in the subgroup of patients with podocytopathies may be due to the early stages of podocyte injury, which are accompanied by transient GBMD.
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Affiliation(s)
- V G Sipovsky
- Acad. I.P. Pavlov First Saint Petersburg State Medical University, Ministry of Health of Russia, Saint-Petersburg, Russia
| | - A I Nevorotin
- Acad. I.P. Pavlov First Saint Petersburg State Medical University, Ministry of Health of Russia, Saint-Petersburg, Russia
| | - I V Avsiewitsch
- Acad. I.P. Pavlov First Saint Petersburg State Medical University, Ministry of Health of Russia, Saint-Petersburg, Russia
| | - A V Smirnov
- Acad. I.P. Pavlov First Saint Petersburg State Medical University, Ministry of Health of Russia, Saint-Petersburg, Russia
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van Daalen EE, Neeskens P, Zandbergen M, Harper L, Karras A, Vaglio A, de Zoysa J, Bruijn JA, Bajema IM. Podocytes and Proteinuria in ANCA-Associated Glomerulonephritis: A Case-Control Study. Front Immunol 2019; 10:1405. [PMID: 31297110 PMCID: PMC6607406 DOI: 10.3389/fimmu.2019.01405] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2019] [Accepted: 06/04/2019] [Indexed: 12/23/2022] Open
Abstract
Proteinuria has been identified as prognosticator of renal outcome in patients with ANCA-associated glomerulonephritis, but whether proteinuria is related to podocyte abnormalities in these patients is largely unknown. We here investigate podocyte foot process width and number of podocytes positive for the podocyte marker WT-1 in diagnostic renal biopsies of 25 Caucasian patients with ANCA-associated glomerulonephritis in relation to proteinuria. Control tissue was used from pre-transplantation donor kidney biopsies. Proteinuria at 10 weeks follow-up correlated significantly with foot process width (P = 0.04). Biopsies with foot process width ≥600 nm belonged more often to the crescentic or mixed class, whereas biopsies with a foot process width <600 nm were most often categorized as focal class (P = 0.03). The mean number of podocytes based upon expression of WT-1 was significantly lower in patients compared to controls (15 vs. 34 podocytes per glomerulus; P < 0.0001). The significant decrease in expression of the podocyte WT-1 marker in ANCA-associated glomerulonephritis is considered indicative of actual podocyte loss or at least, of a loss of functionality. Furthermore, our study indicates that podocyte foot process width at baseline could be indicative for proteinuria at short term follow up. For prognostic purposes, we therefore suggest to include a description of the foot process width in the diagnostic report of a biopsy with ANCA-associated glomerulonephritis.
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Affiliation(s)
- Emma E. van Daalen
- Department of Pathology, Leiden University Medical Center, Leiden, Netherlands
| | - Peter Neeskens
- Department of Pathology, Leiden University Medical Center, Leiden, Netherlands
| | - Malu Zandbergen
- Department of Pathology, Leiden University Medical Center, Leiden, Netherlands
| | - Lorraine Harper
- School of Immunity and Infection, College of Medical and Dental Sciences, University of Birmingham, Birmingham, United Kingdom
| | - Alexandre Karras
- Nephrology Department, HEGP Hospital, Assistance Publique Hôpitaux de Paris, Paris, France
| | - Augusto Vaglio
- Nephrology Unit, Meyer Children's Hospital and Department of Biomedical Experimental and Clinical Sciences “Mario Serio”, University of Firenze, Firenze, Italy
| | - Janak de Zoysa
- Renal Services, North Shore Hospital, Auckland, New Zealand
| | - Jan A. Bruijn
- Department of Pathology, Leiden University Medical Center, Leiden, Netherlands
| | - Ingeborg M. Bajema
- Department of Pathology, Leiden University Medical Center, Leiden, Netherlands
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The Case | An unusual cause of renal impairment and hematuria in aortic dissection. Kidney Int 2019; 96:255-256. [PMID: 31229044 DOI: 10.1016/j.kint.2019.01.011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2018] [Revised: 01/22/2019] [Accepted: 01/24/2019] [Indexed: 11/20/2022]
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The bias between different albumin assays may affect clinical decision-making. Kidney Int 2019; 95:1514-1517. [DOI: 10.1016/j.kint.2019.01.042] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2018] [Revised: 01/30/2019] [Accepted: 01/31/2019] [Indexed: 01/08/2023]
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Anigilaje EA, Olutola A. Prospects of genetic testing for steroid-resistant nephrotic syndrome in Nigerian children: a narrative review of challenges and opportunities. Int J Nephrol Renovasc Dis 2019; 12:119-136. [PMID: 31190951 PMCID: PMC6512787 DOI: 10.2147/ijnrd.s193874] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
The prevalence of childhood steroid-resistant nephrotic syndrome (SRNS) ranges from 35% to 92%. This steroid resistance among Nigerian children also reflects underlying renal histopathology, revealing a rare minimal-change disease and a varying burden of membranoproliferative glomerulonephritis and focal segmental glomerulosclerosis (FSGS). FSGS tends to progress to end-stage kidney disease, which requires dialysis and/or renal transplantation. While knowledge of the molecular basis of NS is evolving, recent data support the role of mutant genes that otherwise maintain the structural and functional composition of the glomerular filtration barrier to account for many monogenic forms of FSGS. With the advent of next-generation sequencing, >39 genes are currently associated with SRNS, and the number is likely to increase in the near future. Monogenic FSGS is primarily resistant to steroids, and this foreknowledge obviates the need for steroids, other immunosuppressive therapy, and renal biopsy. Therefore, a multidisciplinary collaboration among cell biologists, molecular physiologists, geneticists, and clinicians holds prospects of fine-tuning the management of SRNS caused by known mutant genes. This article describes the genetics of NS/SRNS in childhood and also gives a narrative review of the challenges and opportunities for molecular testing among children with SRNS in Nigeria. For these children to benefit from genetic diagnosis, Nigeria must aspire to have and develop the manpower and infrastructure required for medical genetics and genomic medicine, leveraging on her existing experiences in genomic medicine. Concerted efforts can be put in place to increase the number of enrollees in Nigeria’s National Health Insurance Scheme (NHIS). The scope of the NHIS can be expanded to cater for the expensive bill of genetic testing within or outside the structure of the National Renal Care Policy proposed by Nigerian nephrologists.
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Affiliation(s)
- Emmanuel Ademola Anigilaje
- Nephrology Unit, Department of Paediatrics, Faculty of Clinical Sciences, College of Health Sciences, University of Abuja, Abuja, Nigeria,
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Odenthal J, Brinkkoetter PT. Drosophila melanogaster and its nephrocytes: A versatile model for glomerular research. Methods Cell Biol 2019; 154:217-240. [PMID: 31493819 DOI: 10.1016/bs.mcb.2019.03.011] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/04/2022]
Abstract
Glomerular disorders are a predominant cause of chronic kidney diseases and end-stage renal failure. Especially podocytes, epithelial cells which represent the outermost part of the filtration barrier, are affected by disease and experience a gradual loss of function. Despite recent advances in identifying potential pathways underlying podocyte injury, treatment remains challenging. It is therefore desirable to employ suitable model organisms in order to study glomerular disease and elucidate affected pathways. Due to its diverse ways of genetic manipulation and high genomic conservation, Drosophila melanogaster is a powerful model organism for biomedical research. The fly was recently used to assess podocytopathies by exploiting the nephrocyte system. Nephrocytes are spherical cells within the body cavity of the fly responsible for detoxification and clearance of unwanted substances. More importantly, they share many characteristics with mammalian podocytes. Here, we summarize how to use Drosophila as a model organism for podocyte research. We discuss examples of techniques that can be used to genetically manipulate nephrocytes and provide protocols for nephrocyte isolation and for morphological as well as functional analysis.
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Affiliation(s)
- Johanna Odenthal
- Department II of Internal Medicine and Center for Molecular Medicine Cologne, University of Cologne, Faculty of Medicine and University Hospital Cologne, Cologne, Germany; CECAD, University of Cologne, Faculty of Medicine and University Hospital Cologne, Cologne, Germany
| | - Paul Thomas Brinkkoetter
- Department II of Internal Medicine and Center for Molecular Medicine Cologne, University of Cologne, Faculty of Medicine and University Hospital Cologne, Cologne, Germany; CECAD, University of Cologne, Faculty of Medicine and University Hospital Cologne, Cologne, Germany.
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Kukull B, Avasare RS, Smith KD, Houghton DC, Troxell ML, Andeen NK. Collapsing glomerulopathy in older adults. Mod Pathol 2019; 32:532-538. [PMID: 30327500 DOI: 10.1038/s41379-018-0154-z] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2018] [Revised: 08/20/2018] [Accepted: 08/21/2018] [Indexed: 01/25/2023]
Abstract
Collapsing glomerulopathy has been described in settings of viral infections, drug, genetic, ischemic, renal transplant, and idiopathic conditions. It has a worse prognosis than other morphologic variants of focal segmental glomerulosclerosis, and may be treated with aggressive immunosuppression. In this study, we sought to characterize the clinical and morphologic findings in older adults with collapsing glomerulopathy. Renal biopsies and associated clinical data from patients aged 65 or older with a diagnosis of collapsing glomerulopathy were retrospectively reviewed at 3 academic institutions. Patients (n = 41, 61% male, median age 71) usually had hypertension (88%), nephrotic range proteinuria (91%), and renal insufficiency (median serum creatinine 2.5 mg/dL). A likely precipitating drug (5%) or vascular procedure (5%) was identified in a minority of cases; viral infections were infrequent. Renal biopsies contained a median of 40% globally and 16% segmentally sclerotic glomeruli. Approximately 60% of cases had moderate or severe arteriosclerosis, arteriolar hyalinosis, and/or tubular atrophy and interstitial fibrosis; 7% had atheroembolic disease and 5% had thrombotic microangiopathy. In 28 patients with available follow-up information, eight (19%) were treated with immunosuppressives, which were not tolerated by 2. At a median interval of 14 months, 5 (18%) patients had died, 12 (43%) had end stage renal disease, and 12 were alive with renal insufficiency and proteinuria. Treatment with immunosuppressive therapy did not have a significant benefit with regard to the primary outcome of overall or renal survival. One steroid-treated patient with diabetes died 6 weeks after biopsy, with invasive rhinoorbital Rhizopus infection. In conclusion, collapsing glomerulopathy in older patients is usually not associated with viral infections, and is accompanied by significant chronic injury in glomeruli, vasculature, and tubulointerstitium. Aggressive immunosuppression likely contributed to one death in a patient with diabetes, and did not yield an overall or renal survival advantage in this cohort.
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Affiliation(s)
- Benjamin Kukull
- Department of Pathology, Oregon Health & Science University, Portland, OR, USA
| | - Rupali S Avasare
- Department of Medicine, Division of Nephrology, Oregon Health & Science University, Portland, OR, USA
| | - Kelly D Smith
- Department of Pathology, University of Washington, Seattle, WA, USA
| | - Donald C Houghton
- Department of Pathology, Oregon Health & Science University, Portland, OR, USA
| | - Megan L Troxell
- Department of Pathology, Stanford University, Stanford, CA, USA
| | - Nicole K Andeen
- Department of Pathology, Oregon Health & Science University, Portland, OR, USA.
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Nili F, Saboori F, Jahanzad I, Mehrazma M. Electron microscopic findings suggestive of focal and segmental glomerulosclerosis in patients with steroid-resistant nephrotic syndrome. Ultrastruct Pathol 2019; 43:6-12. [PMID: 30835594 DOI: 10.1080/01913123.2019.1584258] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Distinction between minimal change disease and unsampled Focal Segmental Glomerulosclerosis is a challenging concept in kidney biopsy of patients with nephrotic syndrome with minimal histopathological findings. This study was performed to compare electron microscopic findings in patients with steroid-resistant nephrotic syndrome with minimal histopathological abnormalities and cases with Focal Segmental Glomerulosclerosis. This Cohort study was conducted in Cancer Institute, Imam Khomeini Hospital Complex, Tehran, Iran. Twenty patients with steroid-resistant nephrotic syndrome and minimal changes on the light microscopic study were selected as case group. Similarly, 20 patients with Focal Segmental Glomerulosclerosis were selected as the control group. Ultrastructural findings were re-evaluated and scored qualitatively (0-3+). In patients with minimal changes on light microscopic evaluation, clinical course of the disease was followed after 5 years. Mean ages of the patients (8 women and 12 men) in case and control groups were 12.9 and 15.9 years, respectively (p > 0.05). There was no significant difference in number of examined glomeruli and sampling from cortico-medullary junction area between the groups. The mean percentage of sclerotic glomeruli in control group was 15.4%. Tubular atrophy and interstitial fibrosis were more frequent in control patients. Podocyte proliferation, GBM duplication (involving more than 10% of capillary walls), and moderate to severe multifocal expansion of mesangial matrix were significantly more obvious in FSGS patient samples (p < 0.05). No statistically significant difference was found in severity of cytoplasmic vacuolization, GBM wrinkling and splitting between the groups. Most of (80%) the patients with minimal changes improved during the 5-year follow-up. Generally, we concluded that Podocyte proliferation, GBM remodeling, and moderate to severe mesangial matrix expansion are the most reliable findings on electron microscopic examination in favor of FSGS.
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Affiliation(s)
- Fatemeh Nili
- a Department of Pathology , Imam Khomeini Hospital Complex, Tehran University of Medical Sciences , Tehran , I.R. Iran
| | - Fatemeh Saboori
- a Department of Pathology , Imam Khomeini Hospital Complex, Tehran University of Medical Sciences , Tehran , I.R. Iran
| | - Issa Jahanzad
- a Department of Pathology , Imam Khomeini Hospital Complex, Tehran University of Medical Sciences , Tehran , I.R. Iran
| | - Mitra Mehrazma
- b Department of Pathology , Shahid Hasheminejad Hospital, Iran University of Medical Sciences , Tehran , I.R. Iran
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