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Ozeki T, Gillespie BW, Larkina M, Maruyama S, Alakwaa F, Kretzler M, Mariani LH. Clinical Course of Adult FSGS and Minimal Change Disease in North American and Japanese Cohorts. Kidney360 2023; 4:924-934. [PMID: 37131280 PMCID: PMC10371276 DOI: 10.34067/kid.0000000000000133] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/27/2022] [Accepted: 04/03/2023] [Indexed: 05/04/2023]
Abstract
Key Points Data from different geographical regions highlighted the differences in clinical manifestations and treatment response of adult FSGS/minimal change disease. There were shared factors that were associated with treatment response across the cohorts: FSGS, higher BP, and lower eGFR. Recognizing geographical difference allows us better understanding of disease biology, risk prediction, and design of future clinical trials. Background Regional differences in presentation and clinical course of nephrotic syndrome (NS) have not been studied well because few studies directly compared the data from different intercontinental regions. Methods We included adult nephrotic patients with FSGS and minimal change disease (MCD) who received immunosuppressive therapy (IST) in a North American (Nephrotic Syndrome Study Network [NEPTUNE], N =89) or Japanese (Nagoya Kidney Disease Registry [N-KDR], N =288) cohort. Baseline characteristics and rates of complete remission (CR) were compared. Factors associated with time to CR were evaluated by Cox regression models. Results NEPTUNE participants had more FSGS (53.9 versus 17.0%) and family history of kidney disease (35.2 versus 3.2%). N-KDR participants were older (median 56 versus 43 years) and demonstrated greater levels of urine protein creatinine ratio (7.73 versus 6.65) and hypoalbuminemia (1.6 versus 2.2 mg/dl). N-KDR participants showed higher proportion of CR (overall: 89.2 versus 62.9%; FSGS: 67.3 versus 43.7%; MCD: 93.7 versus 85.4%). A multivariable model showed that FSGS (versus MCD: hazard ratio [HR], 0.28; 95% confidence interval [CI], 0.20 to 0.41), systolic BP (per 10 mm Hg: HR, 0.93; 95% CI, 0.86 to 0.99), and eGFR (per 10 ml/min per 1.73 m2: HR, 1.16; 95% CI, 1.09 to 1.24) were associated with time to CR. There were significant interactions in patient age (P = 0.004) and eGFR (P = 0.001) between the cohorts. Conclusions The North American cohort had more FSGS and more frequent family history. Japanese patients showed more severe NS with better response to IST. FSGS, hypertension, and lower eGFR were shared predictors of poor treatment response. Identifying shared and unique features across geographically diverse populations may help uncover biologically relevant subgroups, improve prediction of disease course, and better design future multinational clinical trials.
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Affiliation(s)
- Takaya Ozeki
- Division of Nephrology, Department of Internal Medicine, University of Michigan, Ann Arbor, Michigan
- Department of Nephrology, Nagoya University Graduate School of Medicine, Nagoya, Japan
| | - Brenda W. Gillespie
- Department of Biostatistics, School of Public Health, University of Michigan, Ann Arbor, Michigan
| | - Maria Larkina
- Division of Nephrology, Department of Internal Medicine, University of Michigan, Ann Arbor, Michigan
| | - Shoichi Maruyama
- Department of Nephrology, Nagoya University Graduate School of Medicine, Nagoya, Japan
| | - Fadhl Alakwaa
- Division of Nephrology, Department of Internal Medicine, University of Michigan, Ann Arbor, Michigan
| | - Matthias Kretzler
- Division of Nephrology, Department of Internal Medicine, University of Michigan, Ann Arbor, Michigan
| | - Laura H. Mariani
- Division of Nephrology, Department of Internal Medicine, University of Michigan, Ann Arbor, Michigan
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Gilhaus K, Cepok C, Kamm D, Surmann B, Nedvetsky PI, Emich J, Sundukova A, Saatkamp K, Nüsse H, Klingauf J, Wennmann DO, George B, Krahn MP, Pavenstädt HJ, Vollenbröker BA. Activation of Hippo Pathway Damages Slit Diaphragm by Deprivation of Ajuba Proteins. J Am Soc Nephrol 2023; 34:1039-1055. [PMID: 36930055 PMCID: PMC10278832 DOI: 10.1681/asn.0000000000000107] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2022] [Accepted: 02/06/2023] [Indexed: 03/18/2023] Open
Abstract
SIGNIFICANCE STATEMENT Nuclear exclusion of the cotranscription factor YAP, which is a consequence of activation of the Hippo signaling pathway, leads to FSGS and podocyte apoptosis. Ajuba proteins play an important role in the glomerular filtration barrier by keeping the Hippo pathway inactive. In nephrocytes from Drosophila melanogaster , a well-established model system for podocyte research, Ajuba proteins ensure slit diaphragm (SD) formation and function. Hippo pathway activation leads to mislocalization of Ajuba proteins, decreased SD formation, rearrangement of the actin cytoskeleton, and increased SD permeability. Targeting the kinases of the Hippo pathway with specific inhibitors in the glomerulus could, therefore, be a promising strategy for therapy of FSGS. BACKGROUND The highly conserved Hippo pathway, which regulates organ growth and cell proliferation by inhibiting transcriptional cofactors YAP/TAZ, plays a special role in podocytes, where activation of the pathway leads to apoptosis. The Ajuba family proteins (Ajuba, LIM domain-containing protein 1 (LIMD1) and Wilms tumor protein 1-interacting protein [WTIP]) can bind and inactivate large tumor suppressor kinases 1 and 2, (LATS1/2) two of the Hippo pathway key kinases. WTIP, furthermore, connects the slit diaphragm (SD), the specialized cell-cell junction between podocytes, with the actin cytoskeleton. METHODS We used garland cell nephrocytes of Drosophila melanogaster to monitor the role of Ajuba proteins in Hippo pathway regulation and structural integrity of the SD. Microscopy and functional assays analyzed the interplay between Ajuba proteins and LATS2 regarding expression, localization, interaction, and effects on the functionality of the SD. RESULTS In nephrocytes, the Ajuba homolog Djub recruited Warts (LATS2 homolog) to the SD. Knockdown of Djub activated the Hippo pathway. Reciprocally, Hippo activation reduced the Djub level. Both Djub knockdown and Hippo activation led to morphological changes in the SD, rearrangement of the cortical actin cytoskeleton, and increased SD permeability. Knockdown of Warts or overexpression of constitutively active Yki prevented these effects. In podocytes, Hippo pathway activation or knockdown of YAP also decreased the level of Ajuba proteins. CONCLUSIONS Ajuba proteins regulate the structure and function of the SD in nephrocytes, connecting the SD protein complex to the actin cytoskeleton and maintaining the Hippo pathway in an inactive state. Hippo pathway activation directly influencing Djub expression suggests a self-amplifying feedback mechanism.
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Affiliation(s)
- Kevin Gilhaus
- Molecular Nephrology, Medical Clinic D, University Hospital of Münster, Münster, Germany
| | - Claudia Cepok
- Molecular Nephrology, Medical Clinic D, University Hospital of Münster, Münster, Germany
| | - David Kamm
- Molecular Nephrology, Medical Clinic D, University Hospital of Münster, Münster, Germany
| | - Beate Surmann
- Molecular Nephrology, Medical Clinic D, University Hospital of Münster, Münster, Germany
| | - Pavel I. Nedvetsky
- Medical Cell Biology, Medical Clinic D, University Hospital of Münster, Münster, Germany
| | - Jana Emich
- Institute of Reproductive Genetics, University Hospital of Münster, Münster, Germany
| | - Alina Sundukova
- Molecular Nephrology, Medical Clinic D, University Hospital of Münster, Münster, Germany
| | - Katharina Saatkamp
- Molecular Nephrology, Medical Clinic D, University Hospital of Münster, Münster, Germany
| | - Harald Nüsse
- Institute of Medical Physics and Biophysics, Westfälische-Wilhelms University Münster, Münster, Germany
| | - Jürgen Klingauf
- Institute of Medical Physics and Biophysics, Westfälische-Wilhelms University Münster, Münster, Germany
| | - Dirk O. Wennmann
- Molecular Nephrology, Medical Clinic D, University Hospital of Münster, Münster, Germany
| | - Britta George
- Molecular Nephrology, Medical Clinic D, University Hospital of Münster, Münster, Germany
| | - Michael P. Krahn
- Medical Cell Biology, Medical Clinic D, University Hospital of Münster, Münster, Germany
| | | | - Beate A. Vollenbröker
- Molecular Nephrology, Medical Clinic D, University Hospital of Münster, Münster, Germany
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Medina E, Rueda C, Batlle D. FSGS and COVID-19 in Non-African American Patients. Kidney360 2023; 4:687-699. [PMID: 37229730 PMCID: PMC10371264 DOI: 10.34067/kid.0000000000000104] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/10/2022] [Accepted: 02/10/2023] [Indexed: 05/27/2023]
Abstract
Collapsing Focal Segmental Glomerulosclerosis (FSGS) has been reported relatively frequently in African American (AA) patients with coronavirus disease 2019 (COVID-19), and it is associated almost always with Apolipoprotein L gen 1 (APOL1) high-risk variants. We reviewed the published literature from April 2020 to November 2022 searching for non-African American (non-AA) patients with FSGS associated with COVID-19 (eight White patients, six Hispanic patients, three Asian patients, one Indian patient, and one Asian Indian patient). The following histologic patterns were found: collapsing (n=11), not otherwise specified (n=5), tip (n=2), and perihilar (n=1). Fifteen of the 19 patients had AKI. The APOL1 genotype was reported in only six of the 19 non-AA patients. Three of them (two Hispanic patients and one White patient) with collapsing FSGS had high-risk APOL1 variants. The other three patients (two White patients and one Hispanic patient with the collapsing variant, tip variant, and not otherwise specified) had low-risk APOL1 variants. Among 53 African American patients with collapsing FSGS associated with COVID-19, 48 had high-risk APOL1 variants and five had low-risk APOL1 variants. We conclude that in non-AA patients, FSGS is a rare complication of COVID-19. FSGS associated with COVID-19 can occur rarely with low-risk APOL1 variants in non-AA and AA patients. Non-AA patients reported to be associated with high-risk APOL1 variants possibly reflect inaccuracy of self-reported race with AA admixture because of unknown ancestry. Given the importance of APOL1 in the pathogenesis of FSGS associated with viral infection and to avoid racial bias, it seems appropriate that APOL1 testing be considered in patients with FSGS associated with COVID-19, regardless of self-reported race.
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Affiliation(s)
- Elba Medina
- Division of Nephrology, General Hospital of México, Eduardo Liceaga, México City, México
- Master's and PhD Program in Dental and Health Medical Sciences, Universidad Nacional Autónoma de México, México City, México
| | - Carlos Rueda
- Division of Nephrology/Hypertension, Department of Medicine, Feinberg School of Medicine, Northwestern University, Chicago, Illinois
| | - Daniel Batlle
- Division of Nephrology/Hypertension, Department of Medicine, Feinberg School of Medicine, Northwestern University, Chicago, Illinois
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Bronstein R, Pace J, Gowthaman Y, Salant DJ, Mallipattu SK. Podocyte-Parietal Epithelial Cell Interdependence in Glomerular Development and Disease. J Am Soc Nephrol 2023; 34:737-750. [PMID: 36800545 PMCID: PMC10125654 DOI: 10.1681/asn.0000000000000104] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2022] [Accepted: 02/04/2023] [Indexed: 02/19/2023] Open
Abstract
Podocytes and parietal epithelial cells (PECs) are among the few principal cell types within the kidney glomerulus, the former serving as a crucial constituent of the kidney filtration barrier and the latter representing a supporting epithelial layer that adorns the inner wall of Bowman's capsule. Podocytes and PECs share a circumscript developmental lineage that only begins to diverge during the S-shaped body stage of nephron formation-occurring immediately before the emergence of the fully mature nephron. These two cell types, therefore, share a highly conserved gene expression program, evidenced by recently discovered intermediate cell types occupying a distinct spatiotemporal gene expression zone between podocytes and PECs. In addition to their homeostatic functions, podocytes and PECs also have roles in kidney pathogenesis. Rapid podocyte loss in diseases, such as rapidly progressive GN and collapsing and cellular subtypes of FSGS, is closely allied with PEC proliferation and migration toward the capillary tuft, resulting in the formation of crescents and pseudocrescents. PECs are thought to contribute to disease progression and severity, and the interdependence between these two cell types during development and in various manifestations of kidney pathology is the primary focus of this review.
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Affiliation(s)
- Robert Bronstein
- Division of Nephrology, Department of Medicine, Renaissance School of Medicine at Stony Brook University, Stony Brook, New York
| | - Jesse Pace
- Division of Nephrology, Department of Medicine, Renaissance School of Medicine at Stony Brook University, Stony Brook, New York
| | - Yogesh Gowthaman
- Division of Nephrology, Department of Medicine, Renaissance School of Medicine at Stony Brook University, Stony Brook, New York
| | - David J. Salant
- Division of Nephrology, Department of Medicine, Boston University School of Medicine, Boston, Massachusetts
| | - Sandeep K. Mallipattu
- Division of Nephrology, Department of Medicine, Renaissance School of Medicine at Stony Brook University, Stony Brook, New York
- Renal Section, Northport VA Medical Center, Northport, New York
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Abstract
COVID (Coronavirus disease)-19 is a systemic disease and the kidney is one of the target organs of infection. Kidney injury is common and can occur in up to 40% of patients. Several glomerular diseases have been reported in association with COVID-19. Some are likely related to COVID-19 whereas many are likely coincidental. Glomerular diseases that are frequently reported in COVID-19 and have a plausible mechanistic explanation, are likely to be related to COVID-19. On the other hand, glomerular diseases that are seldom reported and have no known plausible mechanism, are likely to be unrelated. Collapsing glomerulopathy (CG) is by far the most prevalent. Its association with COVID-19, resembling human immunodeficiency virus (HIV) and CG, led to the newly proposed term “COVID-19 associated nephropathy” or “COVAN”. High-risk APOL1 genotypes are the major risk factor in COVAN patients. Podocytopathy, membranous nephropathy, pauci-immune crescentic glomerulonephritis, and thrombotic microangiopathy are also reported. In kidney allografts, CG remains the most common glomerular pathology. Patients typically present with acute kidney injury (AKI) or abnormal urinary findings at the time of or shortly after COVID-19 diagnosis. Treatment of glomerular disease in COVID-19 patients is challenging. Providers should cautiously consider balancing risks and benefit of immunosuppression, particularly in patients with active diseases. Short-term outcomes vary but generally remain poor with high morbidity and mortality. Future study of long-term outcomes is needed to improve our understanding of glomerular disease associated with COVID-19.
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Jia T, Xu T, Smeets B, Buhl EM, Moeller MJ, Floege J, Klinkhammer BM, Boor P. The Role of Platelet-Derived Growth Factor in Focal Segmental Glomerulosclerosis. J Am Soc Nephrol 2023; 34:241-257. [PMID: 36351762 PMCID: PMC10103089 DOI: 10.1681/asn.2022040491] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2022] [Accepted: 09/26/2022] [Indexed: 11/11/2022] Open
Abstract
BACKGROUND FSGS is the final common pathway to nephron loss in most forms of severe or progressive glomerular injury. Although podocyte injury initiates FSGS, parietal epithelial cells (PECs) are the main effectors. Because PDGF takes part in fibrotic processes, we hypothesized that the ligand PDGF-B and its receptor PDGFR- β participate in the origin and progression of FSGS. METHODS We challenged Thy1.1 transgenic mice, which express Thy1.1 in the podocytes, with anti-Thy1.1 antibody to study the progression of FSGS. We investigated the role of PDGF in FSGS using challenged Thy1.1 mice, 5/6 nephrectomized mice, Col4 -/- (Alport) mice, patient kidney biopsies, and primary murine PECs, and challenged Thy1.1 mice treated with neutralizing anti-PDGF-B antibody therapy. RESULTS The unchallenged Thy1.1 mice developed only mild spontaneous FSGS, whereas challenged mice developed progressive FSGS accompanied by a decline in kidney function. PEC activation, proliferation, and profibrotic phenotypic switch drove the FSGS. During disease, PDGF-B was upregulated in podocytes, whereas PDGFR- β was upregulated in PECs from both mice and patients with FSGS. Short- and long-term treatment with PDGF-B neutralizing antibody improved kidney function and reduced FSGS, PEC proliferation, and profibrotic activation. In vitro , stimulation of primary murine PECs with PDGF-B recapitulated in vivo findings with PEC activation and proliferation, which was inhibited by PDGF-B antibody or imatinib. CONCLUSION PDGF-B-PDGFR- β molecular crosstalk between podocytes and PECs drives glomerulosclerosis and the progression of FSGS. PODCAST This article contains a podcast at.
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Affiliation(s)
- Ting Jia
- Institute of Pathology, RWTH Aachen University Hospital, Aachen, Germany
- Department of Nephrology, The Second Affiliated Hospital of Xi’an Jiaotong University, Xi’an, China
| | - Tong Xu
- Institute of Pathology, RWTH Aachen University Hospital, Aachen, Germany
| | - Bart Smeets
- Department of Pathology, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands
| | - Eva Miriam Buhl
- Electron Microscopy Facility, RWTH Aachen University Hospital, Aachen, Germany
| | - Marcus Johannes Moeller
- Department of Nephrology and Immunology, RWTH Aachen University Hospital, Aachen, Germany
- Heisenberg Chair for Preventive and Translational Nephrology, RWTH Aachen University Hospital, Aachen, Germany
| | - Jürgen Floege
- Department of Nephrology and Immunology, RWTH Aachen University Hospital, Aachen, Germany
| | - Barbara Mara Klinkhammer
- Institute of Pathology, RWTH Aachen University Hospital, Aachen, Germany
- Department of Nephrology and Immunology, RWTH Aachen University Hospital, Aachen, Germany
| | - Peter Boor
- Institute of Pathology, RWTH Aachen University Hospital, Aachen, Germany
- Electron Microscopy Facility, RWTH Aachen University Hospital, Aachen, Germany
- Department of Nephrology and Immunology, RWTH Aachen University Hospital, Aachen, Germany
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Malik IHO, Ladiwala N, Chinta S, Khan M, Patel K. Severe Acute Respiratory Syndrome Coronavirus 2 Induced Focal Segmental Glomerulosclerosis. Cureus 2020; 12:e10898. [PMID: 33194467 PMCID: PMC7657311 DOI: 10.7759/cureus.10898] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/11/2020] [Indexed: 12/14/2022] Open
Abstract
Focal segmental glomerulosclerosis (FSGS) is a common cause of nephrotic syndrome affecting adults and children. Collapsing focal segmental glomerulosclerosis (FSGS), one of five histologic variants of FSGS is described as segmental or global collapse and sclerosis of the glomerular tufts and has been frequently associated with human immunodeficiency virus-associated nephropathy (HIVAN). Its association with other viral and non-viral causes, medications and other disease states has since been established. Due to its resistance to therapy, rapid progression to end-stage renal disease (ESRD) and overall poorer prognosis, identification with electron microscopy examination of the kidney biopsy sample is required during evaluation.
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Affiliation(s)
| | - Nida Ladiwala
- Internal Medicine, BronxCare Health System, Bronx, USA
| | | | - Muhammad Khan
- Internal Medicine, BronxCare Health System, Bronx, USA
| | - Komal Patel
- Internal Medicine, BronxCare Health System, Bronx, USA
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Affiliation(s)
- Richard A Lafayette
- Division of Nephrology, Department of Medicine, Stanford University, Stanford, California
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Hawkins GA, Friedman DJ, Lu L, McWilliams DR, Chou JW, Sajuthi S, Divers J, Parekh R, Li M, Genovese G, Pollak MR, Hicks PJ, Bowden DW, Ma L, Freedman BI, Langefeld CD. Re-Sequencing of the APOL1-APOL4 and MYH9 Gene Regions in African Americans Does Not Identify Additional Risks for CKD Progression. Am J Nephrol 2015; 42:99-106. [PMID: 26343748 PMCID: PMC4589514 DOI: 10.1159/000439448] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2015] [Accepted: 08/11/2015] [Indexed: 12/31/2022]
Abstract
BACKGROUND In African Americans (AAs), APOL1 G1 and G2 nephropathy risk variants are associated with non-diabetic end-stage kidney disease (ESKD) in an autosomal recessive pattern. Additional risk and protective genetic variants may be present near the APOL1 loci, since earlier age ESKD is observed in some AAs with one APOL1 renal-risk variant, and because the adjacent gene MYH9 is associated with nephropathy in populations lacking G1 and G2 variants. METHODS Re-sequencing was performed across a ∼275 kb region encompassing the APOL1-APOL4 and MYH9 genes in 154 AA cases with non-diabetic ESKD and 38 controls without nephropathy who were heterozygous for a single APOL1 G1 or G2 risk variant. RESULTS Sequencing identified 3,246 non-coding single nucleotide polymorphisms (SNPs), 55 coding SNPs, and 246 insertion/deletions. No new coding variations were identified. Eleven variants, including a rare APOL3 Gln58Ter null variant (rs11089781), were genotyped in a replication panel of 1,571 AA ESKD cases and 1,334 controls. After adjusting for APOL1 G1 and G2 risk effects, these variations were not significantly associated with ESKD. In subjects with <2 APOL1 G1 and/or G2 alleles (849 cases; 1,139 controls), the APOL3 null variant was nominally associated with ESKD (recessive model, OR 1.81; p = 0.026); however, analysis in 807 AA cases and 634 controls from the Family Investigation of Nephropathy and Diabetes did not replicate this association. CONCLUSION Additional common variants in the APOL1-APOL4-MYH9 region do not contribute significantly to ESKD risk beyond the APOL1 G1 and G2 alleles.
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Affiliation(s)
- Gregory A. Hawkins
- Center for Public Health Genomics, Wake Forest School of Medicine, Winston-Salem, NC
- Center for Genomics and Personalized Medicine Research, Wake Forest School of Medicine, Winston-Salem, NC
| | - David J. Friedman
- Department of Internal Medicine, Division of Nephrology, Beth Israel Deaconess Medical Center, Boston MA
| | - Lingyi Lu
- Center for Public Health Genomics, Wake Forest School of Medicine, Winston-Salem, NC
- Department of Biostatistical Sciences, Wake Forest School of Medicine, Winston-Salem, NC
| | - David R. McWilliams
- Center for Public Health Genomics, Wake Forest School of Medicine, Winston-Salem, NC
- Department of Biostatistical Sciences, Wake Forest School of Medicine, Winston-Salem, NC
| | - Jeff W. Chou
- Center for Public Health Genomics, Wake Forest School of Medicine, Winston-Salem, NC
- Department of Biostatistical Sciences, Wake Forest School of Medicine, Winston-Salem, NC
| | - Satria Sajuthi
- Center for Public Health Genomics, Wake Forest School of Medicine, Winston-Salem, NC
- Department of Biostatistical Sciences, Wake Forest School of Medicine, Winston-Salem, NC
| | - Jasmin Divers
- Center for Public Health Genomics, Wake Forest School of Medicine, Winston-Salem, NC
- Department of Biostatistical Sciences, Wake Forest School of Medicine, Winston-Salem, NC
| | - Rulan Parekh
- Nephrology, Hospital for Sick Children, Toronto, CA
| | - Man Li
- Department of Epidemiology, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD
| | | | - Martin R. Pollak
- Department of Internal Medicine, Division of Nephrology, Beth Israel Deaconess Medical Center, Boston MA
| | - Pamela J. Hicks
- Department of Biochemistry and Center for Diabetes Research, Wake Forest School of Medicine, Winston-Salem, NC
| | - Donald W. Bowden
- Center for Genomics and Personalized Medicine Research, Wake Forest School of Medicine, Winston-Salem, NC
- Department of Biochemistry and Center for Diabetes Research, Wake Forest School of Medicine, Winston-Salem, NC
| | - Lijun Ma
- Center for Public Health Genomics, Wake Forest School of Medicine, Winston-Salem, NC
- Department of Internal Medicine, Section on Nephrology, Wake Forest School of Medicine, Winston-Salem, NC
| | - Barry I. Freedman
- Center for Public Health Genomics, Wake Forest School of Medicine, Winston-Salem, NC
- Department of Internal Medicine, Section on Nephrology, Wake Forest School of Medicine, Winston-Salem, NC
| | - Carl D. Langefeld
- Center for Public Health Genomics, Wake Forest School of Medicine, Winston-Salem, NC
- Center for Genomics and Personalized Medicine Research, Wake Forest School of Medicine, Winston-Salem, NC
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Trachtman H, Vento S, Herreshoff E, Radeva M, Gassman J, Stein DT, Savin VJ, Sharma M, Reiser J, Wei C, Somers M, Srivastava T, Gipson DS. Efficacy of galactose and adalimumab in patients with resistant focal segmental glomerulosclerosis: report of the font clinical trial group. BMC Nephrol 2015; 16:111. [PMID: 26198842 PMCID: PMC4511259 DOI: 10.1186/s12882-015-0094-5] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2015] [Accepted: 06/24/2015] [Indexed: 12/13/2022] Open
Abstract
BACKGROUND Patients with resistant focal segmental glomerulosclerosis (FSGS) who are unresponsive to corticosteroids and other immunosuppressive agents are at very high risk of progression to end stage kidney disease. In the absence of curative treatment, current therapy centers on renoprotective interventions that reduce proteinuria and fibrosis. The FONT (Novel Therapies for Resistant FSGS) Phase II clinical trial (NCT00814255, Registration date December 22, 2008) was designed to assess the efficacy of adalimumab and galactose compared to standard medical therapy which was comprised of lisinopril, losartan, and atorvastatin. METHODS Key eligibility criteria were biopsy confirmed primary FSGS or documentation of a causative genetic mutation, urine protein:creatinine ratio >1.0 g/g, and estimated glomerular filtration rate (eGFR) >40 ml/min/1.73 m(2). The experimental treatments - adalimumab, galactose, standard medical therapy-- were administered for 26 weeks. The primary endpoint was a 50 % reduction in proteinuria with stable eGFR. RESULTS Thirty-two subjects were screened and 21 were assigned to one of the three study arms. While none of the adalimumab-treated subjects achieved the primary outcome, 2 subjects in the galactose and 2 in the standard medical therapy arm had a 50 % reduction in proteinuria without a decline in eGFR. The proteinuria response did not correlate with serial changes in the serum glomerular permeability activity measured by the Palb assay or soluble urokinase plasminogen activator receptor (suPAR). There were no serious adverse effects related to treatments in the study. CONCLUSIONS Recruitment into this trial that addressed patients with resistant FSGS fell short of the enrollment goal. Our findings suggest that future studies of novel therapies for rare glomerular diseases such as FSGS may benefit from enrollment of patients earlier in the course of their disease. In addition, better identification of patients who are likely to respond to a new treatment based on biomarkers suggesting involvement of the disease pathway targeted by the experimental agent may reduce the required sample size and increase the likelihood of a favorable outcome.
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Affiliation(s)
- Howard Trachtman
- NYU Langone Medical Center, CTSI, Room #110, 227 E 30th Street, New York, NY, USA.
| | - Suzanne Vento
- NYU Langone Medical Center, CTSI, Room #110, 227 E 30th Street, New York, NY, USA.
| | | | | | | | | | - Virginia J Savin
- Kansas City Veteran's Administration Medical Center, Kansas City, MO, USA.
| | - Mukut Sharma
- Kansas City Veteran's Administration Medical Center, Kansas City, MO, USA.
| | | | - Changli Wei
- Rush University Medical Center, Chicago, IL, USA.
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Pirkle JL, Freedman BI. Hypertension and chronic kidney disease: controversies in pathogenesis and treatment. MINERVA UROL NEFROL 2013; 65:37-50. [PMID: 23538309 PMCID: PMC4030753] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
The relationship between hypertension and chronic kidney disease (CKD) has long been the subject of controversy. The pathogenetic mechanisms of nephropathy in non-diabetic individuals with hypertension, as well as optimal hypertension treatment targets in populations with nephropathy remain important clinical concerns. This manuscript reviews breakthroughs in molecular genetics that have clarified the complex relationship between hypertension and kidney disease, answering the question of which factor comes first. An overview of the potential roles that hyperuricemia plays in the pathogenesis of hypertension and CKD and current blood pressure treatment guidelines in populations with CKD are discussed. The ongoing National Institutes of Health-sponsored Systolic Blood Pressure Intervention Trial (SPRINT) is underway to help answer these important questions. Enrollment of 9250 hypertensive SPRINT participants will be completed in 2013; important results on ideal blood pressure control targets for reducing nephropathy progression, cardiovascular disease end-points, and preserving cognitive function are expected. As such, many of the controversial aspects of hypertension management will likely be clarified in the near future.
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Affiliation(s)
- James L. Pirkle
- Department of Internal Medicine, Section on Nephrology; Wake Forest School of Medicine; Winston-Salem, North Carolina, USA
| | - Barry I. Freedman
- Department of Internal Medicine, Section on Nephrology; Wake Forest School of Medicine; Winston-Salem, North Carolina, USA
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Cravedi P, Kopp JB, Remuzzi G. Recent progress in the pathophysiology and treatment of FSGS recurrence. Am J Transplant 2013; 13:266-74. [PMID: 23312002 PMCID: PMC3558619 DOI: 10.1111/ajt.12045] [Citation(s) in RCA: 82] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2012] [Revised: 11/05/2012] [Accepted: 11/06/2012] [Indexed: 01/25/2023]
Abstract
Focal segmental glomerulosclerosis (FSGS) is a glomerular disease characterized by proteinuria, frequent progression to end-stage renal disease, and recurrence after kidney transplantation in ∼25% of patients, which negatively impacts long-term allograft survival. Experimental studies suggest that abnormalities in T and, possibly, B cells may represent one initial pathogenic trigger, leading to podocyte injury and progressive loss. New data also support the existence of circulating permeability factors able to damage the podocytes, but no single molecule has been consistently identified as the causal pathogenic element in FSGS recurrence. Unfortunately, major progress from mechanistic studies has not translated into substantial advancements in patient treatment, with plasmapheresis (PP) and high doses of cyclosporine (CsA) remaining the mainstays of therapy. Despite consistent experimental and clinical evidence that treatment of proteinuria slows renal function decline in proteinuric nephropathies, maximal use of antiproteinuric agents such as renin angiotensin system antagonists is not routine in the management of FSGS recurrence. More recently, encouraging results have been reported with anti-CD20 depleting antibody rituximab, but further studies are needed to establish its safety/efficacy profile.
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Affiliation(s)
- Paolo Cravedi
- Mario Negri Institute for Pharmacological Research, Clinical Research Center for Rare Diseases “Aldo e Cele Dacco”, Villa Camozzi, Ranica, Bergamo, Italy
| | - Jeffrey B. Kopp
- Kidney Disease Section, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD, USA
| | - Giuseppe Remuzzi
- Mario Negri Institute for Pharmacological Research, Clinical Research Center for Rare Diseases “Aldo e Cele Dacco”, Villa Camozzi, Ranica, Bergamo, Italy,Unit of Nephrology, Azienda Ospedaliera Ospedali Riuniti di Bergamo, Bergamo, Italy
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Abstract
One of the most important functions of the kidney is the filtration of the blood that takes place in the glomeruli. Glomerular epithelial cells (podocytes) have several functions, including regulation of the filtration process and glomerular basement membrane turnover. Dysfunction of podocytes is a major cause of glomerular kidney diseases. Gain-of-function mutations in the TRPC6 channel underlie a subset of familial forms of focal segmental glomerulosclerosis (FSGS). While growing evidence supports an important role of TRPC channels in podocytes, the regulation of these channels has yet to be investigated in freshly isolated glomeruli. Native settings in glomeruli provide, by all means, the most appropriate as well as one of the most challenging environments to study ion channel regulation. Thus, it is important to develop new methods that would better reflect the native settings of the podocytes. To address this question, we have established an experimental approach that allows studying podocytes in the freshly isolated decapsulated intact glomeruli. Here we describe the preparation of the rat glomeruli for patch-clamping, focusing on special conditions required for single-channel analysis of TRPC channels. Several tricks useful for cell-attached patch-clamping of the glomerular podocytes and solutions appropriate for registration of the TRPC channels are also provided.
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Purswani MU, Chernoff MC, Mitchell CD, Seage GR 3rd, Zilleruelo G, Abitbol C, Andiman WA, Kaiser KA, Spiegel H, Oleske JM; IMPAACT 219/219C Study Team. Chronic kidney disease associated with perinatal HIV infection in children and adolescents. Pediatr Nephrol 2012; 27:981-9. [PMID: 22366874 DOI: 10.1007/s00467-011-2097-1] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/16/2011] [Revised: 12/01/2011] [Accepted: 12/02/2011] [Indexed: 12/20/2022]
Abstract
BACKGROUND This study describes the incidence, clinical and demographic characteristics, and spectrum of chronic kidney disease (CKD) in youths with perinatal HIV-1 infection. METHODS Retrospective analysis between May 1993 and December 2006 of subjects with renal disease followed in the Pediatric AIDS Clinical Trials Group 219/219C multicenter study examining the long-term consequences of perinatal HIV infection. Diagnosis confirmation was made utilizing a questionnaire mailed to research sites. Participants with CKD of other etiology than HIV were excluded. Outcome measures were biopsy-diagnosed CKD and, in the absence of biopsy, HIV-associated nephropathy (HIVAN) using established clinical criteria. RESULTS Questionnaires on 191 out of 2,102 participants identified 27 cases of CKD: 14 biopsy-diagnosed and 6 clinical cases of HIVAN, and 7 biopsy-diagnosed cases of immune complex-mediated kidney disease (lupus-like nephritis, 3; IgA nephropathy, 2; membranous nephropathy, 2). Incidence rates for CKD associated with HIV in pre-highly active antiretroviral therapy (HAART) (1993-1997) and HAART (1998-2002, 2003-2006) eras were 0.43, 2.84, and 2.79 events per 1,000 person years respectively. In multivariate analysis, black race and viral load ≥100,000 copies/mL (rate ratios 3.28 and 5.05, p ≤ 0.02) were associated with CKD. CONCLUSIONS A variety of immune complex-mediated glomerulonephritides and HIVAN occurs in this population. Black race and uncontrolled viral replication are risk factors for CKD associated with HIV.
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Bennett MR, Piyaphanee N, Czech K, Mitsnefes M, Devarajan P. NGAL distinguishes steroid sensitivity in idiopathic nephrotic syndrome. Pediatr Nephrol 2012; 27:807-12. [PMID: 22200895 PMCID: PMC4302414 DOI: 10.1007/s00467-011-2075-7] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/25/2011] [Revised: 11/17/2011] [Accepted: 11/18/2011] [Indexed: 01/07/2023]
Abstract
BACKGROUND Idiopathic nephrotic syndrome (NS) is the most common glomerular disorder of childhood. Invasive biopsy remains the diagnostic method of choice for NS. Prognosis correlates with steroid responsiveness, from sensitive (SSNS) to resistant (SRNS). Neutrophil gelatinase-associated lipocalin (NGAL) has been demonstrated to be a powerful risk marker of chronic kidney disease progression. We set out to determine if urine NGAL can distinguish between patients with SRNS, SSNS, and healthy controls. METHODS Urine and clinical data were collected from patients at Cincinnati Children's Hospital who were recently diagnosed with active nephrotic syndrome as well as healthy controls. Participants included SRNS (n = 15), SSNS (n = 14), and healthy controls (n = 10). Urinary NGAL was measured by ELISA and normalized to creatinine. RESULTS Median NGAL was significantly (p < 0.001) higher in SRNS (172.3 ng/ml, IQR 18.8-789) than both SSNS (6.3 ng/ml, IQR 4.9-9.9) and healthy controls (6.5 ng/ml, IQR 4.2-9.1). The area under the curve (AUC) for NGAL to distinguish SRNS from SSNS was 0.91 (p < 0.0001). NGAL levels demonstrated a significant negative correlation with glomerular filtration rate (r = -0.5, p < 0.001). Results did not change with NGAL corrected for urine creatinine and were independent of the degree of proteinuria. CONCLUSIONS NGAL levels differentiate SSNS from SRNS and correlate with disease severity in SRNS.
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Affiliation(s)
- Michael R Bennett
- Division Nephrology and Hypertension, Cincinnati Children's Hospital Medical Center, 3333 Burnet Avenue, ML 7022, Cincinnati, OH 45229, USA.
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Gbadegesin R, Lavin P, Foreman J, Winn M. Pathogenesis and therapy of focal segmental glomerulosclerosis: an update. Pediatr Nephrol 2011; 26:1001-15. [PMID: 21110043 PMCID: PMC3624015 DOI: 10.1007/s00467-010-1692-x] [Citation(s) in RCA: 66] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/25/2010] [Revised: 09/28/2010] [Accepted: 10/04/2010] [Indexed: 02/07/2023]
Abstract
Focal and segmental glomerulosclerosis (FSGS) is an important cause of steroid-resistant nephrotic syndrome in adults and children. It is responsible for 5-20% of all cases of end-stage kidney disease (ESKD) in the United States. The pathogenesis of FSGS has not been fully elucidated; however, data from molecular studies of familial cases in the last two decades suggest that FSGS is a defect of the podocyte. The therapeutic agents available for treatment of FSGS are not very effective and only a small percentage of affected individuals will achieve complete remission. Recent data from molecular biology and molecular genetics has provided insight into the mechanisms of action of old agents and also identification of other novel therapeutic targets. This review focuses on recent advances in the molecular pathogenesis of FSGS and currently available therapeutic agents as well as potential novel therapies.
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Affiliation(s)
- Rasheed Gbadegesin
- Department of Pediatrics, Duke University Medical Center, Durham, NC 27710, USA.
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Trachtman H, Fervenza FC, Gipson DS, Heering P, Jayne DRW, Peters H, Rota S, Remuzzi G, Rump LC, Sellin LK, Heaton JPW, Streisand JB, Hard ML, Ledbetter SR, Vincenti F. A phase 1, single-dose study of fresolimumab, an anti-TGF-β antibody, in treatment-resistant primary focal segmental glomerulosclerosis. Kidney Int 2011; 79:1236-43. [PMID: 21368745 PMCID: PMC3257033 DOI: 10.1038/ki.2011.33] [Citation(s) in RCA: 189] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2010] [Revised: 12/20/2010] [Accepted: 01/04/2011] [Indexed: 11/23/2022]
Abstract
Primary focal segmental glomerulosclerosis (FSGS) is a disease with poor prognosis and high unmet therapeutic need. Here, we evaluated the safety and pharmacokinetics of single-dose infusions of fresolimumab, a human monoclonal antibody that inactivates all forms of transforming growth factor-β (TGF-β), in a phase I open-label, dose-ranging study. Patients with biopsy-confirmed, treatment-resistant, primary FSGS with a minimum estimated glomerular filtration rate (eGFR) of 25 ml/min per 1.73 m(2), and a urine protein to creatinine ratio over 1.8 mg/mg were eligible. All 16 patients completed the study in which each received one of four single-dose levels of fresolimumab (up to 4 mg/kg) and was followed for 112 days. Fresolimumab was well tolerated with pustular rash the only adverse event in two patients. One patient was diagnosed with a histologically confirmed primitive neuroectodermal tumor 2 years after fresolimumab treatment. Consistent with treatment-resistant FSGS, there was a slight decline in eGFR (median decline baseline to final of 5.85 ml/min per 1.73 m(2)). Proteinuria fluctuated during the study with the median decline from baseline to final in urine protein to creatinine ratio of 1.2 mg/mg with all three Black patients having a mean decline of 3.6 mg/mg. The half-life of fresolimumab was ∼14 days, and the mean dose-normalized Cmax and area under the curve were independent of dose. Thus, single-dose fresolimumab was well tolerated in patients with primary resistant FSGS. Additional evaluation in a larger dose-ranging study is necessary.
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MESH Headings
- Adult
- Antibodies, Monoclonal/administration & dosage
- Antibodies, Monoclonal/adverse effects
- Antibodies, Monoclonal/pharmacokinetics
- Antibodies, Monoclonal/therapeutic use
- Antibodies, Monoclonal, Humanized
- Biomarkers/urine
- Biopsy
- Creatinine/urine
- Dose-Response Relationship, Drug
- Europe
- Female
- Glomerular Filtration Rate/drug effects
- Glomerulosclerosis, Focal Segmental/drug therapy
- Glomerulosclerosis, Focal Segmental/immunology
- Glomerulosclerosis, Focal Segmental/pathology
- Glomerulosclerosis, Focal Segmental/physiopathology
- Humans
- Infusions, Parenteral
- Kidney/drug effects
- Kidney/immunology
- Kidney/pathology
- Kidney/physiopathology
- Male
- Middle Aged
- Proteinuria/drug therapy
- Proteinuria/immunology
- Transforming Growth Factor beta/antagonists & inhibitors
- Transforming Growth Factor beta/immunology
- Treatment Outcome
- United States
- Young Adult
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Affiliation(s)
- Howard Trachtman
- Division of Nephrology, Department of Pediatrics, Cohen Children's Medical Center, New Hyde Park, New York, USA.
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Chernin G, Heeringa SF, Vega-Warner V, Schoeb DS, Nürnberg P, Hildebrandt F. Adequate use of allele frequencies in Hispanics--a problem elucidated in nephrotic syndrome. Pediatr Nephrol 2010; 25:261-6. [PMID: 19876656 PMCID: PMC2899680 DOI: 10.1007/s00467-009-1315-6] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/22/2009] [Revised: 08/13/2009] [Accepted: 08/13/2009] [Indexed: 01/19/2023]
Abstract
Previous studies in children with focal segmental glomerulosclerosis (FSGS) and nephrotic syndrome (NS) in the USA have revealed inter-ethnic differences in their clinical presentation and outcome. However, ethnicity was based on self-identification rather than on molecular genetic data. Here, we show that genetic heterogeneity exists in self-identified Hispanic (Spanish-American) patients with steroid-resistant nephrotic syndrome (SRNS), as patients may be either of Caucasian or Mesoamerican (Native-American) genetic background. Twenty-one self-identified Hispanic patients with SRNS from 18 families were initially evaluated for mutations in the NPHS2 and WT1 genes. All patients resided and were cared for in the USA. We performed a total genome search for linkage in all Hispanic patients using 250K single nucleotide polymorphism microarrays, comparing Caucasian with Mesoamerican allele frequencies to determine regions of homozygosity by descent and to establish the correct allele frequency for each family. We found that only ten families (56%) of the 18 self-identified Hispanic families are genetically of Mesoamerican descent, whereas the other eight families (44%) are of Caucasian descent. Due to the small number of families examined, we were unable to draw any conclusion on the prevalence of NPHS2 and WT1 in this ethnic group, but the data do suggest that self-identification of ethnicity in Hispanic-American patients is not an adequate basis for genetic studies, as this cohort may represent not only patients of Mesoamerican origin but also patients of Caucasian origin. Thus, one needs to critically review previous studies of FSGS/SRNS patients that involved Hispanic patients as a group. Future larger studies may employ a total genome search for linkage to test self-identified Hispanic ethnicity for true Mesoamerican versus Caucasian ethnicity in order to generate valid genetic data.
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Affiliation(s)
- Gil Chernin
- Departments of Pediatrics and of Human Genetics, University of Michigan, Ann Arbor, MI, USA
| | - Saskia F. Heeringa
- Departments of Pediatrics and of Human Genetics, University of Michigan, Ann Arbor, MI, USA
| | - Virginia Vega-Warner
- Departments of Pediatrics and of Human Genetics, University of Michigan, Ann Arbor, MI, USA
| | - Dominik S. Schoeb
- Departments of Pediatrics and of Human Genetics, University of Michigan, Ann Arbor, MI, USA
| | - Peter Nürnberg
- Center for Genomics (CCG) and Institute for Genetics, Universität zu Köln, Cologne, Germany
| | - Friedhelm Hildebrandt
- Departments of Pediatrics and of Human Genetics, University of Michigan, Ann Arbor, MI, USA. Howard Hughes Medical Institute, University of Michigan, Ann Arbor, MI, USA. University of Michigan Health System, 8220C MSRB III, 1150 West Medical Center Drive, Ann Arbor, MI 48109-5646, USA
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Gbadegesin R, Bartkowiak B, Lavin PJ, Mukerji N, Wu G, Bowling B, Eckel J, Damodaran T, Winn MP. Exclusion of homozygous PLCE1 (NPHS3) mutations in 69 families with idiopathic and hereditary FSGS. Pediatr Nephrol 2009; 24:281-5. [PMID: 18975016 PMCID: PMC3070354 DOI: 10.1007/s00467-008-1025-5] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/19/2008] [Revised: 09/17/2008] [Accepted: 09/19/2008] [Indexed: 11/27/2022]
Abstract
Focal and segmental glomerulosclerosis (FSGS) is the most common glomerular cause of end-stage kidney disease (ESKD). Although the etiology of FSGS has not been fully elucidated, recent results from the positional cloning of genes mutated in nephrotic syndromes are now beginning to provide insight into the pathogenesis of these diseases. Mutations in PLCE1/NPHS3 have recently been reported as a cause of nephrotic syndrome characterized by diffuse mesangial sclerosis (DMS) histology. One single family with a missense mutation had late onset of the disease that was characterized by FSGS. To further define the role of PLCE1 mutations in the etiology of FSGS, we performed mutational analysis in 69 families with FSGS. A total of 69 families with 231 affected individuals were examined. The median age of disease onset was 26 years (range 1-66 years). Onset of ESKD was at a median age of 35.5 years. Seven variants leading to non-synonymous changes were found, of which only two are new variants (exon 4 c.1682 G>A R561Q, exon 31 c.6518A>G K2173R). No known disease-causing mutations were identified in the families screened. PLCE1/NPHS3 mutations are not a cause of FSGS in this cohort. The absence of mutations in PLCE1/NPHS3 in this study indicates that there are additional genetic causes of FSGS and that hereditary FSGS is a heterogeneous disease. Kindreds appropriate for genome-wide screening are currently being subjected to analysis with the aim of identifying other genetic causes of FSGS.
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Affiliation(s)
- Rasheed Gbadegesin
- Department of Pediatrics, Duke University Medical Center, Durham, NC 27710
- Center for Human Genetics, Duke University Medical Center, Durham, NC 27710
- To whom correspondence should be addressed: Michelle P. Winn Duke University Medical Center, Durham, NC, 27710; and Rasheed Gbadegesin Duke University Medical Center, Durham, NC, 27710
| | - Bartlomiej Bartkowiak
- Department of Pediatrics, Duke University Medical Center, Durham, NC 27710
- Center for Human Genetics, Duke University Medical Center, Durham, NC 27710
| | - Peter J Lavin
- Department of Medicine, Duke University Medical Center, Durham, NC 27710
- Center for Human Genetics, Duke University Medical Center, Durham, NC 27710
| | - Nirvan Mukerji
- Department of Medicine, Duke University Medical Center, Durham, NC 27710
- Center for Human Genetics, Duke University Medical Center, Durham, NC 27710
| | - Guanghong Wu
- Department of Medicine, Duke University Medical Center, Durham, NC 27710
- Center for Human Genetics, Duke University Medical Center, Durham, NC 27710
| | - Brandy Bowling
- Department of Medicine, Duke University Medical Center, Durham, NC 27710
- Center for Human Genetics, Duke University Medical Center, Durham, NC 27710
| | - Jason Eckel
- Department of Medicine, Duke University Medical Center, Durham, NC 27710
- Center for Human Genetics, Duke University Medical Center, Durham, NC 27710
| | - Tirupapuliyur Damodaran
- Department of Medicine, Duke University Medical Center, Durham, NC 27710
- Center for Human Genetics, Duke University Medical Center, Durham, NC 27710
| | - Michelle P Winn
- Department of Medicine, Duke University Medical Center, Durham, NC 27710
- Center for Human Genetics, Duke University Medical Center, Durham, NC 27710
- To whom correspondence should be addressed: Michelle P. Winn Duke University Medical Center, Durham, NC, 27710; and Rasheed Gbadegesin Duke University Medical Center, Durham, NC, 27710
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Abstract
Therapy of primary focal segmental glomerulosclerosis (FSGS) in children incorporates conservative management and immunosuppression regimens to control proteinuria and preserve kidney function. In long-term cohort studies in adults and children with primary FSGS, renal survival has been directly associated with degree of proteinuria control. This educational article reviews the current therapeutic approach toward children with primary FSGS.
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Affiliation(s)
- Debbie S Gipson
- Chapel Hill School of Medicine, University of North Carolina Kidney Center, University of North Carolina, 7012 Burnett-Womack Hall, CB#7155, Chapel Hill, NC, 27599-7155, USA.
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Sato J, Masuda H, Tamaoki S, Hamasaki H, Ishizaka K, Matsubara O, Azuma H. Endogenous asymmetrical dimethylarginine and hypertension associated with puromycin nephrosis in the rat. Br J Pharmacol 1998; 125:469-76. [PMID: 9806329 PMCID: PMC1565650 DOI: 10.1038/sj.bjp.0702101] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
1. The present experiments were designed to investigate the role of asymmetrical NG,NG-dimethyl-L-arginine (ADMA) in causing hypertension associated with the focal and segmental glomerulosclerosis (FSGS) produced by a single bolus of puromycin aminonucleoside (PAN) and successive injection of protamine for 7 days in rats which had undergone unilateral nephrectomy. 2. After the unilateral nephrectomy, and administering PAN and protamine, histological examinations of the kidney revealed a typical FSGS, that is, evident abnormalities including segmental mesangial proliferation, obliteration of glomerular capillary lumens and adhesions between the glomerulus and Bowman's capsule could be observed. Changes in the glomerular epithelial cells consisted of the swelling with bleb formation. 3. In the FSGS rats, urine volume and urinary protein were significantly (P<0.05 and P<0.005) increased throughout 4-week experimental period, while the creatinine clearance was significantly (P<0.005) and transiently decreased, and recovered 4 weeks later. These changes were associated with the sustained elevation of the systolic blood pressure. 4. ADMA levels in aortic endothelial cells, plasma and urine were significantly (P<0.05 and P<0.005) increased in the FSGS rats, but the level in the kidney remained unchanged. 5. The basal level and net production of cyclic GMP in the aortic vessel wall with endothelium when stimulated by norepinephrine and acetylcholine were significantly (P<0.05 and P<0.01) attenuated in the FSGS rats. 6. There were significant and positive correlations between systolic blood pressure (y) and ADMA levels (x) in endothelial cells (y=4.43x+122.2, r=0.979, P<0.0001), plasma (y=0.10x+71.9, r=0.921, P<0.001) and urine (y=0.48x+126.9, r =0.699, P<0.005), but not significant in the kidney (y=0.06x+102.7, r=0.252, NS). 7. These findings suggest that ADMA as an endogenous inhibitor of NO synthesis may play an important role for the pathogenesis in the hypertension associated with the experimental FSGS in the rat.
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Affiliation(s)
- J Sato
- Department of Medicinal Chemistry, Institute for Medical and Dental Engineering, Faculty of Medicine, Tokyo Medical and Dental University, Japan
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