1
|
Bigatti C, Chiarenza DS, Angeletti A. To biopsy or not to biopsy a teenager with idiopathic nephrotic syndrome? Biopsy first. Pediatr Nephrol 2024:10.1007/s00467-024-06510-6. [PMID: 39251432 DOI: 10.1007/s00467-024-06510-6] [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] [Received: 04/23/2024] [Revised: 08/15/2024] [Accepted: 08/16/2024] [Indexed: 09/11/2024]
Abstract
Kidney biopsy plays a crucial role in the diagnosis and management of several glomerular diseases. While it is generally considered a routine and safe procedure in children, it should be conducted with the primary objective of addressing the following question: do the prognosis and treatments vary based on the findings of kidney biopsy? In children presenting with idiopathic nephrotic syndrome (INS), guidelines suggest to consider kidney biopsy for individuals older than 12 years, primarily due to the possible increased incidence of different glomerulonephritis compared to younger patients, who predominantly manifest with minimal change disease. However, these guidelines also advocate for uniform therapeutic strategies, typically steroids, irrespective of the age or histological findings. Whether the age of more than 12 years may be a recommendation for performing kidney biopsy at presentation of INS is debatable. Instead, kidney biopsy could be reserved for steroid-resistant cases. On the other hand, when kidney biopsy is performed in INS, particularly in focal segmental glomerulosclerosis, histology may reveal additional lesions, that are strongly associated with a poorer response to treatment and worse clinical outcomes. Therefore, current guidelines on treatments of nephrotic syndrome may appear overly restrictive, despite the relevant findings provided by kidney biopsy. Therefore, in the present manuscript, which is part of a pro-con debate on the management of nephrotic syndrome in adolescents, we emphasize the potential role of performing a kidney biopsy before initiating corticosteroid treatment.
Collapse
Affiliation(s)
- Carolina Bigatti
- Nephrology, Dialysis and Transplantation Unit, IRCCS Istituto Giannina Gaslini, Via Gaslini 5, 16147, Genoa, GE, Italy
| | - Decimo S Chiarenza
- Nephrology, Dialysis and Transplantation Unit, IRCCS Istituto Giannina Gaslini, Via Gaslini 5, 16147, Genoa, GE, Italy
| | - Andrea Angeletti
- Nephrology, Dialysis and Transplantation Unit, IRCCS Istituto Giannina Gaslini, Via Gaslini 5, 16147, Genoa, GE, Italy.
| |
Collapse
|
2
|
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.
Collapse
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
| |
Collapse
|
3
|
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.
Collapse
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.
| |
Collapse
|
4
|
Wang TY, Chang FP, Yang AH, Ka SM, Chen A, Hsieh JT, Chen FY, Lee TL, Tseng PY, Tsai MT, Li SY, Yang CY, Chen JY, Lin CC, Tarng DC. Key pathological features characterize minimal change disease-like IgA nephropathy. PLoS One 2023; 18:e0288384. [PMID: 37471324 PMCID: PMC10358932 DOI: 10.1371/journal.pone.0288384] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2022] [Accepted: 06/26/2023] [Indexed: 07/22/2023] Open
Abstract
AIMS A subset of IgA nephropathy (IgAN) patients exhibiting minimal change disease (MCD) like features present with nephrotic-range proteinuria and warrants immunosuppressive therapy (IST). However, the diagnosis of MCD-like IgAN varied by reports. We aimed to identify the key pathological features of MCD-like IgAN. METHODS In this cohort, 228 patients had biopsy-proven IgAN from 2009 to 2021, of which 44 without segmental sclerosis were enrolled. Patients were classified into segmental (< 50% glomerular capillary loop involvement) or global (> 50%) foot process effacement (FPE) groups. We further stratified them according to the usage of immunosuppressant therapy after biopsy. Clinical manifestations, treatment response, and renal outcome were compared. RESULTS 26 cases (59.1%) were classified as segmental FPE group and 18 cases (40.9%) as global FPE group. The global FPE group had more severe proteinuria (11.48 [2.60, 15.29] vs. 0.97 [0.14, 1.67] g/g, p = 0.001) and had a higher proportion of complete remission (81.8% vs. 20%, p = 0.018). In the global FPE group, patients without IST experienced more rapid downward eGFR change than the IST-treated population (-0.38 [-1.24, 0.06] vs. 1.26 [-0.17, 3.20]mL/min/1.73 m2/month, p = 0.004). CONCLUSIONS The absence of segmental sclerosis and the presence of global FPE are valuable pathological features that assist in identifying MCD-like IgAN.
Collapse
Affiliation(s)
- Tsung-Yueh Wang
- Department of Medicine, Division of NephrologyTaipei Veterans General Hospital, Taipei, Taiwan
| | - Fu-Pang Chang
- Faculty of Medicine, School of Medicine, National Yang Ming Chiao Tung University, Taipei, Taiwan
- Department of Pathology, Taipei Veterans General Hospital, Taipei, Taiwan
| | - An-Hang Yang
- Faculty of Medicine, School of Medicine, National Yang Ming Chiao Tung University, Taipei, Taiwan
- Department of Pathology, Taipei Veterans General Hospital, Taipei, Taiwan
- Institute of Clinical Medicine, School of Medicine, National Yang Ming Chiao Tung University, Taipei, Taiwan
| | - Shuk-Man Ka
- Graduate Institute of Life Sciences, National Defense Medical Center, Taipei, Taiwan
| | - Ann Chen
- Department of Pathology, Tri-Service General Hospital, National Defense Medical Center, Taipei, Taiwan
| | - Jyh-Tong Hsieh
- Department of Medicine, Division of NephrologyTaipei Veterans General Hospital, Taipei, Taiwan
| | - Fan-Yu Chen
- Department of Medicine, Division of NephrologyTaipei Veterans General Hospital, Taipei, Taiwan
| | - Tsung-Lun Lee
- Department of Medicine, Division of NephrologyTaipei Veterans General Hospital, Taipei, Taiwan
| | - Po-Yu Tseng
- Faculty of Medicine, School of Medicine, National Yang Ming Chiao Tung University, Taipei, Taiwan
- Department of Medicine, Division of Nephrology, Taipei City Hospital, Heping Fuyou Branch, Taipei, Taiwan
| | - Ming-Tsun Tsai
- Department of Medicine, Division of NephrologyTaipei Veterans General Hospital, Taipei, Taiwan
- Faculty of Medicine, School of Medicine, National Yang Ming Chiao Tung University, Taipei, Taiwan
| | - Szu-Yuan Li
- Department of Medicine, Division of NephrologyTaipei Veterans General Hospital, Taipei, Taiwan
- Faculty of Medicine, School of Medicine, National Yang Ming Chiao Tung University, Taipei, Taiwan
| | - Chih-Yu Yang
- Department of Medicine, Division of NephrologyTaipei Veterans General Hospital, Taipei, Taiwan
- Faculty of Medicine, School of Medicine, National Yang Ming Chiao Tung University, Taipei, Taiwan
- Institute of Clinical Medicine, School of Medicine, National Yang Ming Chiao Tung University, Taipei, Taiwan
- Center for Intelligent Drug Systems and Smart Bio-devices (IDS2B), Hsinchu, Taiwan
- Stem Cell Research Center, National Yang Ming Chiao Tung University, Taipei, Taiwan
- Department of Medicine, Division of Clinical Toxicology and Occupational Medicine, Taipei Veterans General Hospital, Taipei, Taiwan
| | - Jinn-Yang Chen
- Department of Medicine, Division of NephrologyTaipei Veterans General Hospital, Taipei, Taiwan
- Faculty of Medicine, School of Medicine, National Yang Ming Chiao Tung University, Taipei, Taiwan
| | - Chih-Ching Lin
- Department of Medicine, Division of NephrologyTaipei Veterans General Hospital, Taipei, Taiwan
- Faculty of Medicine, School of Medicine, National Yang Ming Chiao Tung University, Taipei, Taiwan
| | - Der-Cherng Tarng
- Department of Medicine, Division of NephrologyTaipei Veterans General Hospital, Taipei, Taiwan
- Faculty of Medicine, School of Medicine, National Yang Ming Chiao Tung University, Taipei, Taiwan
- Institute of Clinical Medicine, School of Medicine, National Yang Ming Chiao Tung University, Taipei, Taiwan
- Center for Intelligent Drug Systems and Smart Bio-devices (IDS2B), Hsinchu, Taiwan
| |
Collapse
|
5
|
Kantauskaite M, Fürst G, Minko P, Antoch G, Rump LC, Potthoff SA. How acute renal failure led to the diagnosis of aortic coarctation. J Hypertens 2023; 41:520-524. [PMID: 36728235 PMCID: PMC9894139 DOI: 10.1097/hjh.0000000000003364] [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] [Indexed: 02/03/2023]
Abstract
The present case report focuses on a rare presentation of aortic coarctation. A 38-year-old man with well-controlled arterial hypertension, minimal change glomerulonephritis and colitis ulcerosa was suffering from recurrent acute renal failure episodes during viral gastroenteritis. No other symptoms at rest or during physical activity were present. The workup included renal duplex sonography, which unmasked tardus parvus profile in both kidneys without any acceleration of blood flow in the renal arteries. Further examination included CT angiography, which confirmed the diagnosis of aortic coarctation. The observed narrowing of the aorta measured 4 mm and was treated with percutaneous transluminal angioplasty and stent implantation (final diameter 12 mm). After the procedure, the patient had normal blood pressure values without the need of any medication; duplex sonography showed improved renal perfusion. The present case confirms the importance of evaluation for secondary hypertension and thorough workup of acute renal failure in young patients.
Collapse
Affiliation(s)
| | - Günter Fürst
- Department of Diagnostic and Interventional Radiology, Medical Faculty, University Clinic Duesseldorf, Heinrich-Heine University Duesseldorf, Düsseldorf, Germany
| | - Peter Minko
- Department of Diagnostic and Interventional Radiology, Medical Faculty, University Clinic Duesseldorf, Heinrich-Heine University Duesseldorf, Düsseldorf, Germany
| | - Gerald Antoch
- Department of Diagnostic and Interventional Radiology, Medical Faculty, University Clinic Duesseldorf, Heinrich-Heine University Duesseldorf, Düsseldorf, Germany
| | | | | |
Collapse
|
6
|
Zee J, Liu Q, Smith AR, Hodgin JB, Rosenberg A, Gillespie BW, Holzman LB, Barisoni L, Mariani LH. Kidney Biopsy Features Most Predictive of Clinical Outcomes in the Spectrum of Minimal Change Disease and Focal Segmental Glomerulosclerosis. J Am Soc Nephrol 2022; 33:1411-1426. [PMID: 35581011 PMCID: PMC9257823 DOI: 10.1681/asn.2021101396] [Citation(s) in RCA: 18] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2021] [Accepted: 04/01/2022] [Indexed: 12/19/2022] Open
Abstract
BACKGROUND Heterogeneity in disease course and treatment response among patients with MCD/FSGS necessitates a granular evaluation of kidney tissue features. This study aimed to identify histologic and ultrastructural descriptors of structural changes most predictive of clinical outcomes in the Nephrotic Syndrome Study Network (NEPTUNE). METHODS Forty-eight histologic (37 glomerular, 9 tubulointerstitial, 2 vascular) and 20 ultrastructural descriptors were quantified by applying the NEPTUNE Digital Pathology Scoring System to NEPTUNE kidney biopsies. Outcomes included time from biopsy to disease progression, first complete remission of proteinuria, and treatment response. Relative importance of pathology and clinical predictors was obtained from random forest models, and predictive discrimination was assessed. RESULTS Among 224 participants (34% Black, 24% Hispanic), model performance was excellent, with predictive discrimination of 0.9 for disease progression, 0.85 for complete remission, and 0.81 for treatment response. The most predictive descriptors of outcomes included both conventional-e.g., global sclerosis or segmental sclerosis and interstitial fibrosis/tubular atrophy-and novel features, including adhesion, interstitial foam cells, deflation, periglomerular fibrosis, mononuclear white blood cells, endothelial cell abnormalities, microvillous transformation, and acute tubular injury. CONCLUSIONS The most predictive descriptors of clinical outcomes among MCD/FSGS patients reflected structural changes in multiple renal compartments. Reporting these descriptors should be standardized to guide prognostication of proteinuric glomerular diseases.
Collapse
Affiliation(s)
- Jarcy Zee
- Department of Biostatistics, Epidemiology, and Informatics, University of Pennsylvania, and Children's Hospital of Philadelphia, Philadelphia, Pennsylvania
| | - Qian Liu
- Arbor Research Collaborative for Health, Ann Arbor, Michigan
| | - Abigail R Smith
- Arbor Research Collaborative for Health, Ann Arbor, Michigan
| | - Jeffrey B Hodgin
- Renal Pathology, Department of Pathology and Internal Medicine, Division of Nephrology, University of Michigan, Ann Arbor, Michigan
| | - Avi Rosenberg
- Department of Pathology, Johns Hopkins Medical Institutions, Baltimore, Maryland and Kidney Disease Section, Kidney Diseases Branch, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland
| | - Brenda W Gillespie
- Department of Biostatistics, University of Michigan, Ann Arbor, Michigan
| | - Lawrence B Holzman
- Renal-Electrolyte and Hypertension Division, Department of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Laura Barisoni
- Department of Pathology, Division of AI and Computational Pathology, and Department of Medicine, Division of Nephrology, Duke University, Durham, North Carolina
| | | | | |
Collapse
|
7
|
Li G, Kidd J, Kaspar C, Dempsey S, Bhat OM, Camus S, Ritter JK, Gehr TWB, Gulbins E, Li PL. Podocytopathy and Nephrotic Syndrome in Mice with Podocyte-Specific Deletion of the Asah1 Gene: Role of Ceramide Accumulation in Glomeruli. THE AMERICAN JOURNAL OF PATHOLOGY 2020; 190:1211-1223. [PMID: 32194052 DOI: 10.1016/j.ajpath.2020.02.008] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/07/2020] [Accepted: 02/20/2020] [Indexed: 12/26/2022]
Abstract
Lysosomal acid ceramidase (Ac) has been shown to be critical for ceramide hydrolysis and regulation of lysosome function and cellular homeostasis. In the present study, we generated a knockout mouse strain (Asah1fl/fl/PodoCre) with a podocyte-specific deletion of the α subunit (main catalytic subunit) of Ac. Although no significant morphologic changes in glomeruli were observed in these mice under light microscope, severe proteinuria and albuminuria were found in these podocyte-specific knockout mice compared with control genotype littermates. Transmission electron microscopic analysis showed that podocytes of the knockout mice had distinctive foot process effacement and microvillus formation. These functional and morphologic changes indicate the development of nephrotic syndrome in mice bearing the Asah1 podocyte-specific gene deletion. Ceramide accumulation determined by liquid chromatography-tandem mass spectrometry was demonstrated in isolated glomeruli of Asah1fl/fl/PodoCre mice compared with their littermates. By crossbreeding Asah1fl/fl/PodoCre mice with Smpd1-/- mice, we also produced a double knockout strain, Smpd1-/-/Asah1fl/fl/PodoCre, that also lacks Smpd1, the acid sphingomyelinase that hydrolyzes sphingomyelin to ceramide. These mice exhibited significantly lower levels of glomerular ceramide with decreased podocyte injury compared with Asah1fl/fl/PodoCre mice. These results strongly suggest that lysosomal Ac in podocytes is essential for the maintenance of the structural and functional integrity of podocytes.
Collapse
Affiliation(s)
- Guangbi Li
- Department of Pharmacology and Toxicology, Virginia Commonwealth University, Richmond, Virginia
| | - Jason Kidd
- Division of Nephrology, School of Medicine, Virginia Commonwealth University, Richmond, Virginia
| | - Cristin Kaspar
- Division of Nephrology, School of Medicine, Virginia Commonwealth University, Richmond, Virginia
| | - Sara Dempsey
- Department of Pharmacology and Toxicology, Virginia Commonwealth University, Richmond, Virginia
| | - Owais M Bhat
- Department of Pharmacology and Toxicology, Virginia Commonwealth University, Richmond, Virginia
| | - Sarah Camus
- Department of Pharmacology and Toxicology, Virginia Commonwealth University, Richmond, Virginia
| | - Joseph K Ritter
- Department of Pharmacology and Toxicology, Virginia Commonwealth University, Richmond, Virginia
| | - Todd W B Gehr
- Division of Nephrology, School of Medicine, Virginia Commonwealth University, Richmond, Virginia
| | - Erich Gulbins
- Department of Molecular Biology, University of Duisburg-Essen, Essen, Germany
| | - Pin-Lan Li
- Department of Pharmacology and Toxicology, Virginia Commonwealth University, Richmond, Virginia.
| |
Collapse
|
8
|
Candelier JJ, Lorenzo HK. Idiopathic nephrotic syndrome and serum permeability factors: a molecular jigsaw puzzle. Cell Tissue Res 2019; 379:231-243. [PMID: 31848752 DOI: 10.1007/s00441-019-03147-y] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2019] [Accepted: 11/19/2019] [Indexed: 12/14/2022]
Abstract
Nephrotic syndrome is traditionally defined using the triad of edema, hypoalbuminemia, and proteinuria, but this syndrome is very heterogeneous and difficult to clarify. Its idiopathic form (INS) is probably the most harmful and essentially comprises two entities: minimal change disease (MCD) and focal segmental glomerulosclerosis (FSGS). We will consider some hypotheses regarding the mechanisms underlying INS: (i) the presence of several glomerular permeability factors in the sera of patients that alter the morphology and function of podocytes leading to proteinuria, (ii) the putative role of immune cells. Thanks to recent data, our understanding of these disorders is evolving towards a more multifactorial origin. In this context, circulating factors may be associated according to sequential kinetic mechanisms or micro-environmental changes that need to be determined. In addition, the resulting proteinuria may trigger more proteinuria enhancing the glomerular destabilization.
Collapse
Affiliation(s)
- Jean-Jacques Candelier
- INSERM U1197, Hôpital Paul Brousse, 14 Avenue Paul Vaillant Couturier, 94800, Villejuif, France.,Université Paris-Saclay, Campus Universitaire d'Orsay, 91405, Orsay, France
| | - Hans-Kristian Lorenzo
- INSERM U1197, Hôpital Paul Brousse, 14 Avenue Paul Vaillant Couturier, 94800, Villejuif, France. .,Université Paris-Saclay, Campus Universitaire d'Orsay, 91405, Orsay, France. .,Service de Néphrologie, Hôpital Bicêtre, Faculté de Médecine Paris-Saclay, 94270, Le Kremlin-Bicêtre, France.
| |
Collapse
|
9
|
Siegerist F, Endlich K, Endlich N. Novel Microscopic Techniques for Podocyte Research. Front Endocrinol (Lausanne) 2018; 9:379. [PMID: 30050501 PMCID: PMC6050355 DOI: 10.3389/fendo.2018.00379] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/20/2018] [Accepted: 06/22/2018] [Indexed: 01/16/2023] Open
Abstract
Together with endothelial cells and the glomerular basement membrane, podocytes form the size-specific filtration barrier of the glomerulus with their interdigitating foot processes. Since glomerulopathies are associated with so-called foot process effacement-a severe change of well-formed foot processes into flat and broadened processes-visualization of the three-dimensional podocyte morphology is a crucial part for diagnosis of nephrotic diseases. However, interdigitating podocyte foot processes are too narrow to be resolved by classic light microscopy due to Ernst Abbe's law making electron microscopy necessary. Although three dimensional electron microscopy approaches like serial block face and focused ion beam scanning electron microscopy and electron tomography allow volumetric reconstruction of podocytes, these techniques are very time-consuming and too specialized for routine use or screening purposes. During the last few years, different super-resolution microscopic techniques were developed to overcome the optical resolution limit enabling new insights into podocyte morphology. Super-resolution microscopy approaches like three dimensional structured illumination microscopy (3D-SIM), stimulated emission depletion microscopy (STED) and localization microscopy [stochastic optical reconstruction microscopy (STORM), photoactivated localization microscopy (PALM)] reach resolutions down to 80-20 nm and can be used to image and further quantify podocyte foot process morphology. Furthermore, in vivo imaging of podocytes is essential to study the behavior of these cells in situ. Therefore, multiphoton laser microscopy was a breakthrough for in vivo studies of podocytes in transgenic animal models like rodents and zebrafish larvae because it allows imaging structures up to several hundred micrometer in depth within the tissue. Additionally, along with multiphoton microscopy, lightsheet microscopy is currently used to visualize larger tissue volumes and therefore image complete glomeruli in their native tissue context. Alongside plain visualization of cellular structures, atomic force microscopy has been used to study the change of mechanical properties of podocytes in diseased states which has been shown to be a culprit in podocyte maintenance. This review discusses recent advances in the field of microscopic imaging and demonstrates their currently used and other possible applications for podocyte research.
Collapse
Affiliation(s)
| | | | - Nicole Endlich
- Institute for Anatomy and Cell Biology, University Medicine Greifswald, Greifswald, Germany
| |
Collapse
|
10
|
Siegerist F, Ribback S, Dombrowski F, Amann K, Zimmermann U, Endlich K, Endlich N. Structured illumination microscopy and automatized image processing as a rapid diagnostic tool for podocyte effacement. Sci Rep 2017; 7:11473. [PMID: 28904359 PMCID: PMC5597580 DOI: 10.1038/s41598-017-11553-x] [Citation(s) in RCA: 51] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2017] [Accepted: 08/22/2017] [Indexed: 01/19/2023] Open
Abstract
The morphology of podocyte foot processes is obligatory for renal function. Here we describe a method for the superresolution-visualization of podocyte foot processes using structured illumination microscopy of the slit diaphragm, which before has only been achieved by electron microscopy. As a proof of principle, we measured a mean foot process width of 0.249 ± 0.068 µm in healthy kidneys and a significant higher mean foot process width of 0.675 ± 0.256 µm in minimal change disease patients indicating effacement of foot processes. We then hypothesized that the slit length per glomerular capillary surface area (slit diaphragm density) could be used as an equivalent for the diagnosis of effacement. Using custom-made software we measured a mean value of 3.10 ± 0.27 µm−1 in healthy subjects and 1.83 ± 0.49 µm−1 in the minimal change disease patients. As foot process width was highly correlated with slit diaphragm density (R2 = 0.91), we concluded that our approach is a valid method for the diagnosis of foot process effacement. In summary, we present a new technique to quantify podocyte damage, which combines superresolution microscopy with automatized image processing. Due to its diverse advantages, we propose this technique to be included into routine diagnostics of glomerular histopathology.
Collapse
Affiliation(s)
- Florian Siegerist
- Department of Anatomy and Cell Biology, University Medicine Greifswald, Greifswald, Germany
| | - Silvia Ribback
- Department of Pathology, University Medicine Greifswald, Greifswald, Germany
| | - Frank Dombrowski
- Department of Pathology, University Medicine Greifswald, Greifswald, Germany
| | - Kerstin Amann
- Department of Nephropathology, Institute of Pathology, University of Erlangen-Nürnberg, Erlangen, Germany
| | - Uwe Zimmermann
- Department of Urology, University Medicine Greifswald, Greifswald, Germany
| | - Karlhans Endlich
- Department of Anatomy and Cell Biology, University Medicine Greifswald, Greifswald, Germany
| | - Nicole Endlich
- Department of Anatomy and Cell Biology, University Medicine Greifswald, Greifswald, Germany.
| |
Collapse
|
11
|
Pérez V, López D, Boixadera E, Ibernón M, Espinal A, Bonet J, Romero R. Comparative differential proteomic analysis of minimal change disease and focal segmental glomerulosclerosis. BMC Nephrol 2017; 18:49. [PMID: 28158993 PMCID: PMC5291957 DOI: 10.1186/s12882-017-0452-6] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2016] [Accepted: 01/16/2017] [Indexed: 01/18/2023] Open
Abstract
Background Minimal change disease (MCD) and primary focal segmental glomerulosclerosis (FSGS) are glomerular diseases characterized by nephrotic syndrome. Their diagnosis requires a renal biopsy, but it is an invasive procedure with potential complications. In a small biopsy sample, where only normal glomeruli are observed, FSGS cannot be differentiated from MCD. The correct diagnosis is crucial to an effective treatment, as MCD is normally responsive to steroid therapy, whereas FSGS is usually resistant. The purpose of our study was to discover and validate novel early urinary biomarkers capable to differentiate between MCD and FSGS. Methods Forty-nine patients biopsy-diagnosed of MCD and primary FSGS were randomly subdivided into a training set (10 MCD, 11 FSGS) and a validation set (14 MCD, 14 FSGS). The urinary proteome of the training set was analyzed by two-dimensional differential gel electrophoresis coupled with mass spectrometry. The proteins identified were quantified by enzyme-linked immunosorbent assay in urine samples from the validation set. Results Urinary concentration of alpha-1 antitrypsin, transferrin, histatin-3 and 39S ribosomal protein L17 was decreased and calretinin was increased in FSGS compared to MCD. These proteins were used to build a decision tree capable to predict patient’s pathology. Conclusions This preliminary study suggests a group of urinary proteins as possible non-invasive biomarkers with potential value in the differential diagnosis of MCD and FSGS. These biomarkers would reduce the number of misdiagnoses, avoiding unnecessary or inadequate treatments. Electronic supplementary material The online version of this article (doi:10.1186/s12882-017-0452-6) contains supplementary material, which is available to authorized users.
Collapse
Affiliation(s)
- Vanessa Pérez
- Laboratory of Experimental Nephrology, Institut d'Investigació en Ciències de la Salut Germans Trias i Pujol, Universitat Autònoma de Barcelona, Badalona, Spain. .,Department of Nephrology, Hospital Universitari Germans Trias i Pujol, Universitat Autònoma de Barcelona, Carretera del Canyet s/n, ES-08916, Badalona, Barcelona, Spain.
| | - Dolores López
- Department of Pathology, Hospital Universitari Germans Trias i Pujol, Universitat Autònoma de Barcelona, Badalona, Spain
| | - Ester Boixadera
- Applied Statistics Service, Universitat Autònoma de Barcelona, Bellaterra, Spain
| | - Meritxell Ibernón
- Department of Nephrology, Hospital Universitari Germans Trias i Pujol, Universitat Autònoma de Barcelona, Carretera del Canyet s/n, ES-08916, Badalona, Barcelona, Spain
| | - Anna Espinal
- Applied Statistics Service, Universitat Autònoma de Barcelona, Bellaterra, Spain
| | - Josep Bonet
- Department of Nephrology, Hospital Universitari Germans Trias i Pujol, Universitat Autònoma de Barcelona, Carretera del Canyet s/n, ES-08916, Badalona, Barcelona, Spain
| | - Ramón Romero
- Laboratory of Experimental Nephrology, Institut d'Investigació en Ciències de la Salut Germans Trias i Pujol, Universitat Autònoma de Barcelona, Badalona, Spain.,Department of Nephrology, Hospital Universitari Germans Trias i Pujol, Universitat Autònoma de Barcelona, Carretera del Canyet s/n, ES-08916, Badalona, Barcelona, Spain.,Department of Medicine, Universitat Autònoma de Barcelona, Badalona, Spain
| |
Collapse
|
12
|
|