1
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Reghuvaran AC, Lin Q, Basgen JM, Banu K, Shi H, Vashist A, Pell J, Perinchery S, He JC, Moledina D, Wilson FP, Menon MC. Comparative evaluation of glomerular morphometric techniques reveals differential technical artifacts between focal segmental glomerulosclerosis and normal glomeruli. Physiol Rep 2023; 11:e15688. [PMID: 37423891 PMCID: PMC10329935 DOI: 10.14814/phy2.15688] [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] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2023] [Revised: 04/18/2023] [Accepted: 04/21/2023] [Indexed: 07/11/2023] Open
Abstract
Morphometric estimates of mean or individual glomerular volume (MGV, IGV) have biological implications, over and above qualitative histologic data. However, morphometry is time-consuming and requires expertise limiting its utility in clinical cases. We evaluated MGV and IGV using plastic- and paraffin-embedded tissue from 10 control and 10 focal segmental glomerulosclerosis (FSGS) mice (aging and 5/6th nephrectomy models) using the gold standard Cavalieri (Cav) method versus the 2-profile and Weibel-Gomez (WG) methods and a novel 3-profile method. We compared accuracy, bias and precision, and quantified results obtained when sampling differing numbers of glomeruli. In both FSGS and controls, we identified an acceptable precision for MGV of 10-glomerular sampling versus 20-glomerular sampling using the Cav method, while 5-glomerular sampling was less precise. In plastic tissue, 2- or 3-profile MGVs showed greater concordance with MGV when using Cav, versus MGV with WG. IGV comparisons using the same glomeruli reported a consistent underestimation bias with both 2- or 3-profile methods versus the Cav method. FSGS glomeruli showed wider variations in bias estimation than controls. Our 3-profile method offered incremental benefit to the 2-profile method in both IGV and MGV estimation (improved correlation coefficient, Lin's concordance and reduced bias). In our control animals, we quantified a shrinkage artifact of 52% from tissue processed for paraffin-embedded versus plastic-embedded tissue. FSGS glomeruli showed overall reduced shrinkage albeit with variable artifact signifying periglomerular/glomerular fibrosis. A novel 3-profile method offers slightly improved concordance with reduced bias versus 2-profile. Our findings have implications for future studies using glomerular morphometry.
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Affiliation(s)
- Anand C. Reghuvaran
- Division of Nephrology, Department of MedicineYale University School of MedicineNew HavenConnecticutUSA
| | - Qisheng Lin
- Department of Nephrology, Renji Hospital, School of MedicineShanghai Jiao Tong UniversityShanghaiPeople's Republic of China
| | - John M. Basgen
- Morphometry and Stereology LaboratoryCharles R. Drew University of Medicine and ScienceLos AngelesCaliforniaUSA
| | - Khadija Banu
- Division of Nephrology, Department of MedicineYale University School of MedicineNew HavenConnecticutUSA
| | - Hongmei Shi
- Division of Nephrology, Department of MedicineYale University School of MedicineNew HavenConnecticutUSA
| | - Anushree Vashist
- Division of Nephrology, Department of MedicineYale University School of MedicineNew HavenConnecticutUSA
| | - John Pell
- Division of Nephrology, Department of MedicineYale University School of MedicineNew HavenConnecticutUSA
| | - Sudhir Perinchery
- Department of PathologyYale University School of MedicineNew HavenConnecticutUSA
| | - John C. He
- Division of Nephrology, Department of MedicineIcahn School of Medicine at Mount SinaiNew YorkNew YorkUSA
| | - Dennis Moledina
- Division of Nephrology, Department of MedicineYale University School of MedicineNew HavenConnecticutUSA
- Clinical Translational Research Accelerator, Department of MedicineYale University School of MedicineNew HavenConnecticutUSA
| | - F. Perry Wilson
- Division of Nephrology, Department of MedicineYale University School of MedicineNew HavenConnecticutUSA
- Clinical Translational Research Accelerator, Department of MedicineYale University School of MedicineNew HavenConnecticutUSA
| | - Madhav C. Menon
- Division of Nephrology, Department of MedicineYale University School of MedicineNew HavenConnecticutUSA
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2
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Meliambro K, Yang Y, de Cos M, Rodriguez Ballestas E, Malkin C, Haydak J, Lee JR, Salem F, Mariani LH, Gordon RE, Basgen JM, Wen HH, Fu J, Azeloglu EU, He JC, Wong JS, Campbell KN. KIBRA upregulation increases susceptibility to podocyte injury and glomerular disease progression. JCI Insight 2023; 8:e165002. [PMID: 36853804 PMCID: PMC10132156 DOI: 10.1172/jci.insight.165002] [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] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2022] [Accepted: 02/21/2023] [Indexed: 03/01/2023] Open
Abstract
Despite recent progress in the identification of mediators of podocyte injury, mechanisms underlying podocyte loss remain poorly understood, and cell-specific therapy is lacking. We previously reported that kidney and brain expressed protein (KIBRA), encoded by WWC1, promotes podocyte injury in vitro through activation of the Hippo signaling pathway. KIBRA expression is increased in the glomeruli of patients with focal segmental glomerulosclerosis, and KIBRA depletion in vivo is protective against acute podocyte injury. Here, we tested the consequences of transgenic podocyte-specific WWC1 expression in immortalized human podocytes and in mice, and we explored the association between glomerular WWC1 expression and glomerular disease progression. We found that KIBRA overexpression in immortalized human podocytes promoted cytoplasmic localization of Yes-associated protein (YAP), induced actin cytoskeletal reorganization, and altered focal adhesion expression and morphology. WWC1-transgenic (KIBRA-overexpressing) mice were more susceptible to acute and chronic glomerular injury, with evidence of YAP inhibition in vivo. Of clinical relevance, glomerular WWC1 expression negatively correlated with renal survival among patients with primary glomerular diseases. These findings highlight the importance of KIBRA/YAP signaling to the regulation of podocyte structural integrity and identify KIBRA-mediated injury as a potential target for podocyte-specific therapy in glomerular disease.
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Affiliation(s)
- Kristin Meliambro
- Division of Nephrology, Icahn School of Medicine at Mount Sinai, New York, New York, USA
| | - Yanfeng Yang
- Division of Nephrology, Icahn School of Medicine at Mount Sinai, New York, New York, USA
| | - Marina de Cos
- Division of Nephrology, Icahn School of Medicine at Mount Sinai, New York, New York, USA
| | | | - Caroline Malkin
- Division of Nephrology, Icahn School of Medicine at Mount Sinai, New York, New York, USA
| | - Jonathan Haydak
- Division of Nephrology, Icahn School of Medicine at Mount Sinai, New York, New York, USA
| | - John R. Lee
- Division of Nephrology and Hypertension, Department of Medicine, Weill Cornell Medicine, New York, New York, USA
| | - Fadi Salem
- Department of Laboratory Medicine and Pathology, Mayo Clinic, Jacksonville, Florida, USA
| | - Laura H. Mariani
- Division of Nephrology, Department of Medicine, University of Michigan, Ann Arbor, Michigan, USA
| | - Ronald E. Gordon
- Department of Pathology, Icahn School of Medicine at Mount Sinai, New York, New York, USA
| | - John M. Basgen
- Stereology and Morphometry Laboratory, Charles R. Drew University of Medicine and Science, Los Angeles, California, USA
| | - Huei Hsun Wen
- Division of Nephrology, Icahn School of Medicine at Mount Sinai, New York, New York, USA
| | - Jia Fu
- Division of Nephrology, Icahn School of Medicine at Mount Sinai, New York, New York, USA
| | - Evren U. Azeloglu
- Division of Nephrology, Icahn School of Medicine at Mount Sinai, New York, New York, USA
- Department of Pharmacological Sciences, Icahn School of Medicine at Mount Sinai, New York, New York, USA
| | - John Cijiang He
- Division of Nephrology, Icahn School of Medicine at Mount Sinai, New York, New York, USA
- Department of Pharmacological Sciences, Icahn School of Medicine at Mount Sinai, New York, New York, USA
| | - Jenny S. Wong
- Division of Nephrology, Icahn School of Medicine at Mount Sinai, New York, New York, USA
| | - Kirk N. Campbell
- Division of Nephrology, Icahn School of Medicine at Mount Sinai, New York, New York, USA
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3
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Banu K, Lin Q, Basgen JM, Planoutene M, Wei C, Reghuvaran AC, Tian X, Shi H, Garzon F, Garzia A, Chun N, Cumpelik A, Santeusanio AD, Zhang W, Das B, Salem F, Li L, Ishibe S, Cantley LG, Kaufman L, Lemley KV, Ni Z, He JC, Murphy B, Menon MC. AMPK mediates regulation of glomerular volume and podocyte survival. JCI Insight 2021; 6:e150004. [PMID: 34473647 PMCID: PMC8525649 DOI: 10.1172/jci.insight.150004] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [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] [Received: 04/08/2021] [Accepted: 09/01/2021] [Indexed: 12/20/2022] Open
Abstract
Herein, we report that Shroom3 knockdown, via Fyn inhibition, induced albuminuria with foot process effacement (FPE) without focal segmental glomerulosclerosis (FSGS) or podocytopenia. Interestingly, knockdown mice had reduced podocyte volumes. Human minimal change disease (MCD), where podocyte Fyn inactivation was reported, also showed lower glomerular volumes than FSGS. We hypothesized that lower glomerular volume prevented the progression to podocytopenia. To test this hypothesis, we utilized unilateral and 5/6th nephrectomy models in Shroom3-KD mice. Knockdown mice exhibited less glomerular and podocyte hypertrophy after nephrectomy. FYN-knockdown podocytes had similar reductions in podocyte volume, implying that Fyn was downstream of Shroom3. Using SHROOM3 or FYN knockdown, we confirmed reduced podocyte protein content, along with significantly increased phosphorylated AMPK, a negative regulator of anabolism. AMPK activation resulted from increased cytoplasmic redistribution of LKB1 in podocytes. Inhibition of AMPK abolished the reduction in glomerular volume and induced podocytopenia in mice with FPE, suggesting a protective role for AMPK activation. In agreement with this, treatment of glomerular injury models with AMPK activators restricted glomerular volume, podocytopenia, and progression to FSGS. Glomerular transcriptomes from MCD biopsies also showed significant enrichment of Fyn inactivation and Ampk activation versus FSGS glomeruli. In summary, we demonstrated the important role of AMPK in glomerular volume regulation and podocyte survival. Our data suggest that AMPK activation adaptively regulates glomerular volume to prevent podocytopenia in the context of podocyte injury.
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Affiliation(s)
- Khadija Banu
- Division of Nephrology, Department of Medicine, Icahn School of Medicine at Mount Sinai, New York, New York, USA.,Division of Nephrology, Department of Medicine, Yale University School of Medicine, New Haven, Connecticut, USA
| | - Qisheng Lin
- Division of Nephrology, Department of Medicine, Icahn School of Medicine at Mount Sinai, New York, New York, USA.,Department of Nephrology, Renji Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China
| | - John M Basgen
- Morphometry and Stereology Laboratory, Charles R. Drew University of Medicine and Science, Los Angeles, California, USA
| | - Marina Planoutene
- Division of Nephrology, Department of Medicine, Icahn School of Medicine at Mount Sinai, New York, New York, USA
| | - Chengguo Wei
- Division of Nephrology, Department of Medicine, Icahn School of Medicine at Mount Sinai, New York, New York, USA
| | - Anand C Reghuvaran
- Division of Nephrology, Department of Medicine, Yale University School of Medicine, New Haven, Connecticut, USA
| | - Xuefei Tian
- Division of Nephrology, Department of Medicine, Yale University School of Medicine, New Haven, Connecticut, USA
| | - Hongmei Shi
- Division of Nephrology, Department of Medicine, Yale University School of Medicine, New Haven, Connecticut, USA
| | - Felipe Garzon
- Division of Nephrology, Department of Medicine, Icahn School of Medicine at Mount Sinai, New York, New York, USA
| | - Aitor Garzia
- Laboratory of RNA Molecular Biology, The Rockefeller University, New York, New York, USA
| | - Nicholas Chun
- Division of Nephrology, Department of Medicine, Icahn School of Medicine at Mount Sinai, New York, New York, USA
| | - Arun Cumpelik
- Division of Nephrology, Department of Medicine, Icahn School of Medicine at Mount Sinai, New York, New York, USA
| | - Andrew D Santeusanio
- Division of Nephrology, Department of Medicine, Yale University School of Medicine, New Haven, Connecticut, USA
| | - Weijia Zhang
- Division of Nephrology, Department of Medicine, Icahn School of Medicine at Mount Sinai, New York, New York, USA
| | - Bhaskar Das
- Division of Nephrology, Department of Medicine, Icahn School of Medicine at Mount Sinai, New York, New York, USA
| | - Fadi Salem
- Department of Pathology, Icahn School of Medicine at Mount Sinai, New York, New York, USA
| | - Li Li
- Department of Pathology, Icahn School of Medicine at Mount Sinai, New York, New York, USA
| | - Shuta Ishibe
- Division of Nephrology, Department of Medicine, Yale University School of Medicine, New Haven, Connecticut, USA
| | - Lloyd G Cantley
- Division of Nephrology, Department of Medicine, Yale University School of Medicine, New Haven, Connecticut, USA
| | - Lewis Kaufman
- Division of Nephrology, Department of Medicine, Icahn School of Medicine at Mount Sinai, New York, New York, USA
| | - Kevin V Lemley
- Department of Pediatrics, Children's Hospital Los Angeles, University of Southern California, Los Angeles, California, USA
| | - Zhaohui Ni
- Department of Nephrology, Renji Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China
| | - John Cijiang He
- Division of Nephrology, Department of Medicine, Icahn School of Medicine at Mount Sinai, New York, New York, USA
| | - Barbara Murphy
- Division of Nephrology, Department of Medicine, Icahn School of Medicine at Mount Sinai, New York, New York, USA
| | - Madhav C Menon
- Division of Nephrology, Department of Medicine, Icahn School of Medicine at Mount Sinai, New York, New York, USA.,Division of Nephrology, Department of Medicine, Yale University School of Medicine, New Haven, Connecticut, USA
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4
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Basgen JM, Wong JS, Ray J, Nicholas SB, Campbell KN. Podocyte Foot Process Effacement Precedes Albuminuria and Glomerular Hypertrophy in CD2-Associated Protein Deficient Mice. Front Med (Lausanne) 2021; 8:745319. [PMID: 34568396 PMCID: PMC8460869 DOI: 10.3389/fmed.2021.745319] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [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] [Received: 07/21/2021] [Accepted: 08/20/2021] [Indexed: 12/15/2022] Open
Abstract
Background: Podocyte foot process effacement is a key histologic finding in proteinuric kidney disease. We previously showed that 3-week old CD2AP-deficient mice have significant proteinuria, glomerular hypertrophy and mesangial expansion. The goal of this study is to use morphometry to establish the temporal sequence of podocyte foot process effacement, glomerular volume expansion and albuminuria in Cd2ap−/− mice by measuring these parameters at the 2-week time point. Methods: Wild-type mice age 14 ± 1 days with the Cd2ap gene (WT, N = 5) and mice deficient for Cd2ap (Cd2ap KO, N = 5) were generated. Kidneys were harvested and fixed in 2.5% glutaraldehyde and processed for examination by light and electron microscopy. An average of 415.2 (range 268–716) grid points were counted for all the glomeruli, and quantification of glomerular volume from each kidney. Urine was collected the day prior to sacrifice for urine albumin-to-creatinine ratio (ACR) measurements. Results: There was no difference in albuminuria [median (range) mg/g] between WT [212.2 (177.6–388.4) mg/g] vs. Cd2ap KO mice [203.3 (164.7–910.2) mg/g], P = 0.89; or glomerular volume 68,307[10,931] vs. 66,844[13,022] μm3, p = 0.92. The volume densities of glomerular components of the podocyte, capillary lumen and mesangium were not different for the two groups, P = 0.14, 0.14 and 0.17 respectively. However, foot process width was increased in Cd2ap KO 1128[286] vs. WT [374 ± 42] nm, P = 0.02. Conclusion: Here we show that while 2-week old WT and Cd2ap KO mice have similar levels of albuminuria, glomerular and mesangial volume, Cd2ap KO mice have more extensive podocyte foot process effacement. The data suggests that podocyte injury is the initiating event leading to mesangial expansion and albuminuria in this model.
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Affiliation(s)
- John M Basgen
- Department of Research, Stereology and Morphometry Laboratory, Charles R. Drew University of Medicine and Science, Los Angeles, CA, United States
| | - Jenny S Wong
- Division of Nephrology, Icahn School of Medicine at Mount Sinai, New York, NY, United States
| | - Justina Ray
- Division of Nephrology, Icahn School of Medicine at Mount Sinai, New York, NY, United States
| | - Susanne B Nicholas
- Division of Nephrology, David Geffen School of Medicine at University of California, Los Angeles, CA, United States
| | - Kirk N Campbell
- Division of Nephrology, Icahn School of Medicine at Mount Sinai, New York, NY, United States
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5
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Takeda A, Murayama K, Okazaki Y, Imai-Okazaki A, Ohtake A, Takakuwa E, Yamazawa H, Izumi G, Abe J, Nagai A, Taniguchi K, Sasaki D, Tsujioka T, Basgen JM. Advanced pathological study for definite diagnosis of mitochondrial cardiomyopathy. J Clin Pathol 2020; 74:jclinpath-2020-206801. [PMID: 32817174 DOI: 10.1136/jclinpath-2020-206801] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [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: 05/26/2020] [Revised: 07/03/2020] [Accepted: 07/05/2020] [Indexed: 11/03/2022]
Abstract
AIMS Mitochondrial cardiomyopathy (MCM) is difficult to make a definite diagnosis because of various cardiovascular phenotypes and no diagnostic criteria in the pathology examination. We aim to add myocardial pathology to the diagnostic criteria for mitochondrial respiratory chain disorders. METHODS Quantitative analysis of mitochondria using electron microscopy and immunohistopathological analysis with respiratory chain enzyme antibodies were performed in 11 patients with hypertrophic or restrictive cardiomyopathy who underwent endomyocardial biopsy for possible MCM . Respiratory chain enzymatic assay in biopsied myocardium and genetic studies were also performed in all the subjects to define MCM. RESULTS Four patients were diagnosed with MCM according to the recent criteria of mitochondrial respiratory chain disorders. Using electron microscopy with quantitative analysis, the volume density of mitochondria within cardiac muscle cells was significantly increased in the MCM group compared with the non-MCM group (p=0.007). Immunohistopathological results were compatible with the result of the respiratory chain enzymatic assay. CONCLUSIONS Pathological diagnosis of MCM could be confirmed by a quantitative study of electron microscopy and immunohistopathological analysis using the mitochondrial respiratory chain enzyme subunit antibody.
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Affiliation(s)
- Atsuhito Takeda
- Department of Pediatrics, Faculty of Medicine and Graduate School of Medicine, Hokkaido University, Sapporo, Japan
| | - Kei Murayama
- Department of Metabolism, Chiba Children's Hospital, Chiba, Japan
| | - Yasushi Okazaki
- Diagnostics and Therapeutics of Intractable Diseases, Intractable Disease Research Center, Juntendo University School of Medicine Graduate School of Medicine, Bunkyo-ku, Tokyo, Japan
| | - Atsuko Imai-Okazaki
- Diagnostics and Therapeutics of Intractable Diseases, Intractable Disease Research Center, Juntendo University School of Medicine Graduate School of Medicine, Bunkyo-ku, Tokyo, Japan
| | - Akira Ohtake
- Department of Pediatrics & Clinical Genomics, Saitama Medical University Faculty of Medicine, Saitama, Japan
- Center for Intractable Diseases, Saitama Medical University, Saitama, Japan
| | - Emi Takakuwa
- Department of Surgical Pathology, Hokkaido University Hospital, Sapporo, Japan
| | - Hirokuni Yamazawa
- Department of Pediatrics, Faculty of Medicine and Graduate School of Medicine, Hokkaido University, Sapporo, Japan
| | - Gaku Izumi
- Department of Pediatrics, Faculty of Medicine and Graduate School of Medicine, Hokkaido University, Sapporo, Japan
| | - Jiro Abe
- Department of Pediatrics, Faculty of Medicine and Graduate School of Medicine, Hokkaido University, Sapporo, Japan
| | - Ayako Nagai
- Department of Pediatrics, Faculty of Medicine and Graduate School of Medicine, Hokkaido University, Sapporo, Japan
| | - Kota Taniguchi
- Department of Pediatrics, Faculty of Medicine and Graduate School of Medicine, Hokkaido University, Sapporo, Japan
| | - Daisuke Sasaki
- Department of Pediatrics, Faculty of Medicine and Graduate School of Medicine, Hokkaido University, Sapporo, Japan
| | - Takao Tsujioka
- Department of Pediatrics, Faculty of Medicine and Graduate School of Medicine, Hokkaido University, Sapporo, Japan
| | - John M Basgen
- Department of Research, Charles R Drew University of Medicine and Science, Los Angeles, California, USA
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6
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Wei C, Banu K, Garzon F, Basgen JM, Philippe N, Yi Z, Liu R, Choudhuri J, Fribourg M, Liu T, Cumpelik A, Wong J, Khan M, Das B, Keung K, Salem F, Campbell KN, Kaufman L, Cravedi P, Zhang W, O'Connell PJ, He JC, Murphy B, Menon MC. SHROOM3-FYN Interaction Regulates Nephrin Phosphorylation and Affects Albuminuria in Allografts. J Am Soc Nephrol 2018; 29:2641-2657. [PMID: 30341149 PMCID: PMC6218856 DOI: 10.1681/asn.2018060573] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [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: 06/01/2018] [Accepted: 09/14/2018] [Indexed: 12/11/2022] Open
Abstract
BACKGROUND We previously showed that the presence of a CKD-associated locus in SHROOM3 in a donor kidney results in increased expression of SHROOM3 (an F-actin-binding protein important for epithelial morphogenesis, via rho-kinase [ROCK] binding); this facilitates TGF-b signaling and allograft fibrosis. However, other evidence suggests Shroom3 may have a protective role in glomerular development. METHODS We used human data, Shroom3 knockdown podocytes, and inducible shRNA-mediated knockdown mice to study the role of Shroom3 in adult glomeruli. RESULTS Expression data from the Nephroseq database showed glomerular and nonglomerular SHROOM3 had opposing associations with renal function in CKD biopsy samples. In human allografts, homozygosity at rs17319721, the SHROOM3 locus linked with lower GFR, was associated with reduced albuminuria by 2 years after transplant. Although our previous data showed reduced renal fibrosis with tubular Shroom3 knockdown, this study found that glomerular but not tubular Shroom3 knockdown induced albuminuria. Electron microscopy revealed diffuse foot process effacement, and glomerular RNA-sequencing showed enrichment of tyrosine kinase signaling and podocyte actin cytoskeleton pathways in knockdown mice. Screening SHROOM3-interacting proteins identified FYN (a src-kinase) as a candidate.We confirmed the interaction of endogenous SHROOM3 with FYN in human podocytes via a critical Src homology 3-binding domain, distinct from its ROCK-binding domain. Shroom3-Fyn interaction was required in vitro and in vivo for activation of Fyn kinase and downstream nephrin phosphorylation in podocytes. SHROOM3 knockdown altered podocyte morphology, cytoskeleton, adhesion, and migration. CONCLUSIONS We demonstrate a novel mechanism that may explain SHROOM3's dichotomous associations in glomerular versus nonglomerular compartments in CKD.
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Affiliation(s)
- Chengguo Wei
- Division of Nephrology, Department of Medicine and
| | - Khadija Banu
- Division of Nephrology, Department of Medicine and
| | | | - John M Basgen
- Morphometry and Stereology Laboratory, Charles R. Drew University of Medicine and Science, Los Angeles, California
| | | | - Zhengzi Yi
- Division of Nephrology, Department of Medicine and
| | - Ruijie Liu
- Division of Nephrology, Department of Medicine and
| | | | - Miguel Fribourg
- Department of Neurology, Icahn School of Medicine at Mount Sinai, New York, New York
| | - Tong Liu
- Center for Advanced Proteomics, Department of Biochemistry and Molecular Biology, New Jersey Medical School, Newark, New Jersey; and
| | | | - Jenny Wong
- Division of Nephrology, Department of Medicine and
| | - Mubeen Khan
- Division of Nephrology, Department of Medicine and
| | - Bhaskar Das
- Division of Nephrology, Department of Medicine and
| | - Karen Keung
- Renal Unit, University of Sydney at Westmead Hospital, Sydney, Australia
| | - Fadi Salem
- Division of Nephrology, Department of Medicine and
| | | | | | | | - Weijia Zhang
- Division of Nephrology, Department of Medicine and
| | - Philip J O'Connell
- Renal Unit, University of Sydney at Westmead Hospital, Sydney, Australia
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7
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Zhou Y, Castonguay P, Sidhom EH, Clark AR, Dvela-Levitt M, Kim S, Sieber J, Wieder N, Jung JY, Andreeva S, Reichardt J, Dubois F, Hoffmann SC, Basgen JM, Montesinos MS, Weins A, Johnson AC, Lander ES, Garrett MR, Hopkins CR, Greka A. A small-molecule inhibitor of TRPC5 ion channels suppresses progressive kidney disease in animal models. Science 2018; 358:1332-1336. [PMID: 29217578 DOI: 10.1126/science.aal4178] [Citation(s) in RCA: 108] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2016] [Revised: 07/14/2017] [Accepted: 10/24/2017] [Indexed: 12/26/2022]
Abstract
Progressive kidney diseases are often associated with scarring of the kidney's filtration unit, a condition called focal segmental glomerulosclerosis (FSGS). This scarring is due to loss of podocytes, cells critical for glomerular filtration, and leads to proteinuria and kidney failure. Inherited forms of FSGS are caused by Rac1-activating mutations, and Rac1 induces TRPC5 ion channel activity and cytoskeletal remodeling in podocytes. Whether TRPC5 activity mediates FSGS onset and progression is unknown. We identified a small molecule, AC1903, that specifically blocks TRPC5 channel activity in glomeruli of proteinuric rats. Chronic administration of AC1903 suppressed severe proteinuria and prevented podocyte loss in a transgenic rat model of FSGS. AC1903 also provided therapeutic benefit in a rat model of hypertensive proteinuric kidney disease. These data indicate that TRPC5 activity drives disease and that TRPC5 inhibitors may be valuable for the treatment of progressive kidney diseases.
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Affiliation(s)
- Yiming Zhou
- Department of Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, MA 02115, USA.,Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA
| | - Philip Castonguay
- Department of Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, MA 02115, USA.,Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA
| | - Eriene-Heidi Sidhom
- Department of Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, MA 02115, USA.,Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA
| | - Abbe R Clark
- Department of Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, MA 02115, USA.,Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA
| | - Moran Dvela-Levitt
- Department of Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, MA 02115, USA.,Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA
| | - Sookyung Kim
- Department of Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, MA 02115, USA.,Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA
| | - Jonas Sieber
- Department of Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, MA 02115, USA.,Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA
| | - Nicolas Wieder
- Department of Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, MA 02115, USA.,Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA
| | - Ji Yong Jung
- Department of Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, MA 02115, USA.,Department of Internal Medicine, Gachon University Gil Medical Center, Incheon, Republic of Korea
| | - Svetlana Andreeva
- Department of Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, MA 02115, USA
| | - Jana Reichardt
- Department of Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, MA 02115, USA
| | - Frank Dubois
- Department of Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, MA 02115, USA
| | - Sigrid C Hoffmann
- Medical Research Center, Medical Faculty Mannheim, University Heidelberg, Germany
| | - John M Basgen
- Life Sciences Institute, Charles R. Drew University of Science and Medicine, Los Angeles, CA 90059, USA
| | - Mónica S Montesinos
- Department of Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, MA 02115, USA.,Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA
| | - Astrid Weins
- Department of Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, MA 02115, USA.,Department of Pathology, Brigham and Women's Hospital, Boston, MA 02115, USA
| | - Ashley C Johnson
- Department of Pharmacology and Toxicology, University of Mississippi Medical Center, Jackson, MS 39216, USA
| | - Eric S Lander
- Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA
| | - Michael R Garrett
- Department of Pharmacology and Toxicology, University of Mississippi Medical Center, Jackson, MS 39216, USA
| | - Corey R Hopkins
- Department of Pharmaceutical Sciences, University of Nebraska Medical Center, Omaha, NE 68198, USA
| | - Anna Greka
- Department of Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, MA 02115, USA.,Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA
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Singh R, Parveen M, Basgen JM, Fazel S, Meshesha MF, Thames EC, Moore B, Martinez L, Howard CB, Vergnes L, Reue K, Pervin S. Increased Expression of Beige/Brown Adipose Markers from Host and Breast Cancer Cells Influence Xenograft Formation in Mice. Mol Cancer Res 2015; 14:78-92. [PMID: 26464213 DOI: 10.1158/1541-7786.mcr-15-0151] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2015] [Accepted: 09/30/2015] [Indexed: 12/28/2022]
Abstract
UNLABELLED The initiation and progression of breast cancer is a complex process that is influenced by heterogeneous cell populations within the tumor microenvironment. Although adipocytes have been shown to promote breast cancer development, adipocyte characteristics involved in this process remain poorly understood. In this study, we demonstrate enrichment of beige/brown adipose markers, contributed from the host as well as tumor cells, in the xenografts from breast cancer cell lines. In addition to uncoupling protein-1 (UCP1) that is exclusively expressed in beige/brown adipocytes, gene expression for classical brown (MYF5, EVA1, and OPLAH) as well as beige (CD137/TNFRSF9 and TBX1) adipocyte markers was also elevated in the xenografts. Enrichment of beige/brown characteristics in the xenografts was independent of the site of implantation of the breast tumor cells. Early stages of xenografts showed an expansion of a subset of mammary cancer stem cells that expressed PRDM16, a master regulator of brown adipocyte differentiation. Depletion of UCP1(+) or Myf5(+) cells significantly reduced tumor development. There was increased COX2 (MT-CO2) expression, which is known to stimulate formation of beige adipocytes in early xenografts and treatment with a COX2 inhibitor (SC236) reduced tumor growth. In contrast, treatment with factors that induce brown adipocyte differentiation in vitro led to larger tumors in vivo. A panel of xenografts derived from established breast tumor cells as well as patient tumor tissues were generated that expressed key brown adipose tissue-related markers and contained cells that morphologically resembled brown adipocytes. IMPLICATIONS This is the first report demonstrating that beige/brown adipocyte characteristics could play an important role in breast tumor development and suggest a potential target for therapeutic drug design.
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Affiliation(s)
- Rajan Singh
- Charles R. Drew University of Medicine and Science, Los Angeles, California. Department of Obstetrics and Gynecology, David Geffen School of Medicine at UCLA, Los Angeles, California. Jonsson Comprehensive Cancer Center at UCLA, Los Angeles, California
| | - Meher Parveen
- Charles R. Drew University of Medicine and Science, Los Angeles, California
| | - John M Basgen
- Charles R. Drew University of Medicine and Science, Los Angeles, California
| | - Sayeda Fazel
- Charles R. Drew University of Medicine and Science, Los Angeles, California
| | - Meron F Meshesha
- Charles R. Drew University of Medicine and Science, Los Angeles, California
| | | | - Brandis Moore
- Charles R. Drew University of Medicine and Science, Los Angeles, California
| | - Luis Martinez
- Charles R. Drew University of Medicine and Science, Los Angeles, California
| | | | - Laurent Vergnes
- Department of Human Genetics, David Geffen School of Medicine at UCLA, Los Angeles, California
| | - Karen Reue
- Department of Human Genetics, David Geffen School of Medicine at UCLA, Los Angeles, California
| | - Shehla Pervin
- Charles R. Drew University of Medicine and Science, Los Angeles, California. Department of Obstetrics and Gynecology, David Geffen School of Medicine at UCLA, Los Angeles, California. Jonsson Comprehensive Cancer Center at UCLA, Los Angeles, California.
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9
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Weins A, Wong JS, Basgen JM, Gupta R, Daehn I, Casagrande L, Lessman D, Schwartzman M, Meliambro K, Patrakka J, Shaw A, Tryggvason K, He JC, Nicholas SB, Mundel P, Campbell KN. Dendrin ablation prolongs life span by delaying kidney failure. Am J Pathol 2015; 185:2143-57. [PMID: 26073036 DOI: 10.1016/j.ajpath.2015.04.011] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/23/2014] [Revised: 04/01/2015] [Accepted: 04/21/2015] [Indexed: 12/16/2022]
Abstract
Podocyte loss is central to the progression of proteinuric kidney diseases leading to end-stage kidney disease (ESKD), requiring renal replacement therapy, such as dialysis. Despite modern tools and techniques, the 5-year mortality of some patients requiring dialysis remains at about 70% to 80%. Thus, there is a great unmet need for podocyte-specific treatments aimed at preventing podocyte loss and the ensuing development of ESKD. Here, we show that ablation of the podocyte death-promoting protein dendrin delays the onset of ESKD, thereby expanding the life span of mice lacking the adapter protein CD2AP. Ablation of dendrin delays onset and severity of proteinuria and podocyte loss. In addition, dendrin ablation ameliorates mesangial volume expansion and up-regulation of mesangial fibronectin expression, which is mediated by a podocyte-secreted factor. In conclusion, onset of ESKD and death can be markedly delayed by blocking the function of dendrin.
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Affiliation(s)
- Astrid Weins
- Department of Pathology, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts; Department of Medicine, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts
| | - Jenny S Wong
- Division of Nephrology, Icahn School of Medicine at Mount Sinai, New York, New York
| | - John M Basgen
- Department of Research, Morphometry and Stereology Laboratory, Charles R. Drew University of Medicine and Science, Los Angeles, California
| | - Ritu Gupta
- Department of Pathology, Albert Einstein College of Medicine, Medicine, Bronx, New York
| | - Ilse Daehn
- Division of Nephrology, Icahn School of Medicine at Mount Sinai, New York, New York
| | - Lisette Casagrande
- Division of Nephrology, Icahn School of Medicine at Mount Sinai, New York, New York
| | - David Lessman
- Division of Nephrology, Icahn School of Medicine at Mount Sinai, New York, New York
| | - Monica Schwartzman
- Division of Nephrology, Icahn School of Medicine at Mount Sinai, New York, New York
| | - Kristin Meliambro
- Division of Nephrology, Icahn School of Medicine at Mount Sinai, New York, New York
| | - Jaakko Patrakka
- KI/AZ Integrated CardioMetabolic Center (ICMC), Department of Medicine, Karolinska Institute at Karolinska University Hospital Huddinge, Stockholm, Sweden
| | - Andrey Shaw
- Division of Immunobiology, Washington University School of Medicine, St. Louis, Missouri
| | - Karl Tryggvason
- Department of Medical Biochemistry and Biophysics, Karolinska Institute, Stockholm, Sweden
| | - John Cijiang He
- Division of Nephrology, Icahn School of Medicine at Mount Sinai, New York, New York
| | - Susanne B Nicholas
- Division of Nephrology, University of California Los Angeles, Los Angeles, California
| | - Peter Mundel
- Department of Medicine, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts
| | - Kirk N Campbell
- Division of Nephrology, Icahn School of Medicine at Mount Sinai, New York, New York.
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10
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Schwartzman M, Reginensi A, Wong JS, Basgen JM, Meliambro K, Nicholas SB, D'Agati V, McNeill H, Campbell KN. Podocyte-Specific Deletion of Yes-Associated Protein Causes FSGS and Progressive Renal Failure. J Am Soc Nephrol 2015; 27:216-26. [PMID: 26015453 DOI: 10.1681/asn.2014090916] [Citation(s) in RCA: 65] [Impact Index Per Article: 7.2] [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: 09/22/2014] [Accepted: 04/02/2015] [Indexed: 11/03/2022] Open
Abstract
FSGS is the most common primary glomerular disease underlying ESRD in the United States and is increasing in incidence globally. FSGS results from podocyte injury, yet the mechanistic details of disease pathogenesis remain unclear. This has resulted in an unmet clinical need for cell-specific therapy in the treatment of FSGS and other proteinuric kidney diseases. We previously identified Yes-associated protein (YAP) as a prosurvival signaling molecule, the in vitro silencing of which increases podocyte susceptibility to apoptotic stimulus. YAP is a potent oncogene that is a prominent target for chemotherapeutic drug development. In this study, we tested the hypothesis that podocyte-specific deletion of Yap leads to proteinuric kidney disease through increased podocyte apoptosis. Yap was selectively silenced in podocytes using Cre-mediated recombination controlled by the podocin promoter. Yap silencing in podocytes resulted in podocyte apoptosis, podocyte depletion, proteinuria, and an increase in serum creatinine. Histologically, features characteristic of FSGS, including mesangial sclerosis, podocyte foot process effacement, tubular atrophy, interstitial fibrosis, and casts, were observed. In human primary FSGS, we noted reduced glomerular expression of YAP. Taken together, these results suggest a role for YAP as a physiologic antagonist of podocyte apoptosis, the signaling of which is essential for maintaining the integrity of the glomerular filtration barrier. These data suggest potential nephrotoxicity with strategies directed toward inhibition of YAP function. Further studies should evaluate the role of YAP in proteinuric glomerular disease pathogenesis and its potential utility as a therapeutic target.
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Affiliation(s)
- Monica Schwartzman
- Division of Nephrology, Icahn School of Medicine at Mount Sinai, New York, New York
| | - Antoine Reginensi
- Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, Toronto, Ontario, Canada
| | - Jenny S Wong
- Division of Nephrology, Icahn School of Medicine at Mount Sinai, New York, New York
| | - John M Basgen
- Department of Research, Morphometry and Stereology Laboratory, Charles R. Drew University of Medicine and Science, Los Angeles, California
| | - Kristin Meliambro
- Division of Nephrology, Icahn School of Medicine at Mount Sinai, New York, New York
| | - Susanne B Nicholas
- Department of Research, Morphometry and Stereology Laboratory, Charles R. Drew University of Medicine and Science, Los Angeles, California; Department of Medicine, Division of Nephrology, University of California Los Angeles, Los Angeles, California; and
| | - Vivette D'Agati
- Department of Pathology, Columbia University College of Physicians and Surgeons, New York, New York
| | - Helen McNeill
- Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, Toronto, Ontario, Canada
| | - Kirk N Campbell
- Division of Nephrology, Icahn School of Medicine at Mount Sinai, New York, New York;
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11
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Basgen JM, Sobin C. Early chronic low-level lead exposure produces glomerular hypertrophy in young C57BL/6J mice. Toxicol Lett 2013; 225:48-56. [PMID: 24300173 DOI: 10.1016/j.toxlet.2013.11.031] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [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: 10/23/2013] [Revised: 11/21/2013] [Accepted: 11/22/2013] [Indexed: 11/30/2022]
Abstract
Early chronic lead exposure continues to pose serious health risks for children, particularly those living in lower socioeconomic environments. This study examined effects on developing glomeruli in young C57BL/6J mice exposed to low (30 ppm), higher (330 ppm) or no lead via dams' drinking water from birth to sacrifice on post-natal day 28. Low-level lead exposed mice [BLL mean (SD); 3.19 (0.70) μg/dL] had an increase in glomerular volume but no change in podocyte number compared to control mice [0.03 (0.01) μg/dL]. Higher-level lead exposed mice [14.68 (2.74) μg/dL] had no change in either glomerular volume or podocyte number. The increase in glomerular volume was explained by increases in glomerular capillary and mesangial volumes with no change in podocyte volume. Early chronic lead exposure yielding very low blood lead levels alters glomerular development in pre-adolescent animals.
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Affiliation(s)
- John M Basgen
- Life Sciences Institute, Charles R. Drew University of Medicine and Science, 1731 E 120th Street, Los Angeles, CA 90059, USA.
| | - Christina Sobin
- Department of Public Health Sciences, College of Health Science, University of Texas, El Paso, El Paso, TX 79902, USA; Border Biomedical Research Center, College of Science, University of Texas, El Paso, El Paso, TX, USA; Laboratory of Neuroendocrinology, The Rockefeller University, New York, NY, USA.
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12
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Abstract
BACKGROUND The podocyte serves the important function of maintaining the glomerular filtration barrier, and many studies report a decrease in podocyte number relative to the development of proteinuric states. However, there is significant inconsistency in the number of podocytes counted, possibly due to different counting methods. We previously counted the three glomerular cell types in the mouse kidney and showed that the fractionator/disector method is a close approximation of the exhaustive count or the gold standard method. In this study, we compared the commonly used model-based approach with the design-based approach to count podocytes in the db/m and db/db mouse and illustrate that the design-based approach, which uses the fractionator/disector method, provides an accurate determination of podocyte number. METHODS In the design-based approach, toluidine blue-stained 1-μm-thick sections from glutaraldehyde perfusion-fixed kidneys were used (n = 15) with the fractionator/disector method. In the model-based approach, WT-1-immunolabeled podocyte nuclei in 3- to 4-μm-thick formalin-fixed paraffin-embedded sections of the same kidneys were counted with the Weibel-Gomez method. Glomerular volume was determined for each method. RESULTS We discovered that the fractionator/disector method counted 89 ± 10 podocytes compared to the Weibel-Gomez method, which counted 137 ± 38 podocytes and overestimated podocyte number by 54% (p < 0.05). In addition, glomerular volume (231 ± 52 × 10(3) vs. 192 ± 64 × 10(3) μm(3)) was significantly underestimated by 17% (p < 0.0002). Moreover, the model-based approach was more time consuming. CONCLUSION We conclude that the fractionator/disector method offers an unbiased and efficient determination of podocyte counts.
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Affiliation(s)
- Susanne B Nicholas
- Department of Medicine, David Geffen School of Medicine, UCLA, Los Angeles, CA 90095, USA.
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13
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Abstract
BACKGROUND/AIMS The podocyte is an important cell for maintaining the normal structure and function of the glomerulus. In recent years much attention has been given to the number of podocytes in glomeruli. During this time there has been a debate as to whether podocytes can divide after the capillary-loop stage of development. The aim of this study was to use an unbiased counting method to determine if podocyte number increases after the capillary-loop stage of development. METHODS The fractionator/disector method was used to count podocytes in glomeruli from rats aged 1 day, 5, 12, and 24 weeks. Glomerular volume was also measured with the unbiased Cavalieri principle and used to calculate the density of podocytes per glomerulus. RESULTS The number of podocytes did not increase from the capillary-loop stage of glomerular development to 24 weeks of age. Glomerular volume increased 3.6-fold during this time, which resulted in a decrease of podocyte density as the rats aged. CONCLUSION The study documents that the number of podocytes is stable after the capillary-loop stage of glomerular development. The data does not confirm but adds evidence that podocytes do not divide from the capillary-loop stage of glomerular development to 24 weeks of age in the normal rat.
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Affiliation(s)
- Xiao Yan Bai
- Department of Pathology, Nanfang Hospital, Guangzhou, PR China
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14
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Basgen JM, Nicholas SB, Mauer M, Rozen S, Nyengaard JR. Comparison of methods for counting cells in the mouse glomerulus. Nephron Clin Pract 2006; 103:e139-48. [PMID: 16636586 DOI: 10.1159/000092905] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2005] [Accepted: 12/01/2005] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND Researchers have long been interested in counting the number of cells within the glomerulus. Investigators using different techniques have yielded conflicting results. The most direct method is to count the cells in serial sections from the entire glomerulus. This Exhaustive Count method is not usually practical. The disector/fractionator method counts the number of cells in a fraction of sections. The total is estimated from the product of the cell count and the reciprocal of the fraction. The Weibel-Gomez method determines the density of cells per glomerulus, then multiplies this density by glomerular volume to obtain cell number. In this study, we compared the disector/fractionator and Weibel-Gomez methods to identify a practical alternative for the time-consuming Exhaustive Count method. METHODS Glomeruli from a normal mouse kidney were completely sectioned and images obtained. Appropriate images were used to count glomerular cell number using each method. RESULTS The Exhaustive Count method yielded 213 +/- 22 (mean +/- SD) cells/glomerulus vs. the disector/fractionator average of 211 +/- 29 cells/glomerulus (p = 0.82). The Weibel-Gomez method average of 235 +/- 26 cells/glomerulus was statistically different from the Exhaustive Count method (p = 0.003). CONCLUSION The Weibel-Gomez produced a 10% overestimation, whereas the disector/fractionator method was unbiased and thus a good substitute for the Exhaustive Count method.
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Affiliation(s)
- John M Basgen
- Department of Pediatrics, University of Minnesota, Minneapolis, Minnesota, USA
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15
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Nicholas SB, Mauer M, Basgen JM, Aguiniga E, Chon Y. Effect of angiotensin II on glomerular structure in streptozotocin-induced diabetic rats. Am J Nephrol 2004; 24:549-56. [PMID: 15539791 DOI: 10.1159/000082001] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2004] [Accepted: 10/06/2004] [Indexed: 11/19/2022]
Abstract
BACKGROUND/AIMS The streptozotocin (STZ)-induced diabetic rat is a widely used animal model of human diabetic nephropathy. In this model, diabetic nephropathy progresses without significant elevation in blood pressure. Therefore, studies have examined the effect of hypertension in STZ spontaneously hypertensive rats (SHR). This study investigated angiotensin II (Ang II)-induced hypertension in diabetic nephropathy in the STZ-diabetic rat independent of deleterious genetic effects in SHR. METHODS Animals were divided as follows: nondiabetic controls (ND; n = 18); diabetic (STZ: 65 mg/kg; n = 16); Ang II-induced hypertensive ND (Ang II: 120 ng/kg/min; n = 9), and hypertensive diabetic rats (n = 18). Systolic blood pressure was measured by the tail-cuff method prior to STZ injection and then weekly. After 3 months, plasma creatinine, and 24-hour urine albumin and creatinine were measured and kidneys harvested for morphometry. RESULTS Ang II infusion increased systolic blood pressure in diabetic and ND rats. When combined with diabetes, Ang II increased albumin excretion rate (14-fold, p < 0.05), plasma creatinine (1.5-fold, p < 0.005) worsened creatinine clearance (37%, p < 0.002) and increased glomerular basement membrane width (1.2-fold, p < 0.0001). CONCLUSION Ang II caused moderate hypertension and accelerated diabetic nephropathy and glomerular structural changes. The Ang II-infused STZ-diabetic rat is an excellent model to study the deleterious glomerular effects of hypertension on diabetes independent of genetic traits.
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Affiliation(s)
- Susanne B Nicholas
- Department of Medicine, Division of Nephrology and Endocrinology, David Geffen School of Medicine at UCLA, Los Angeles, Calif., USA.
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Abstract
Glomerular structure has been studied in tissues derived from normal living and cadaver kidney donors. Values obtained in such subjects were considered interchangeable and have been used to define the normal parameters when evaluating the effects of various renal diseases. The present study evaluated glomerular structure by light and electron microscopy in 83 living and 53 cadaver kidney donors. Glomerular basement membrane (GBM) width (356 +/- 52 versus 329 +/- 45 nm), glomerular volume (1.64 +/- 0.47 versus 1.33 +/- 0.39 x 10(6) microm(3)), and mesangial matrix volume per glomerulus (0.15 +/- 0.05 versus 0.12 +/- 0.04 x 10(6) microm(3)) were significantly greater in cadaver compared with living kidney donors, respectively. It is hypothesized that glomerular and extracellular matrix swelling is associated with the cadaver kidney preservation process. This study suggests that the normal values for glomerular structure should be derived only from living kidney donor tissues.
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Affiliation(s)
- M Luiza Caramori
- Department of Pediatrics, University of Minnesota, 420 Delaware Street SE, Minneapolis, MN 55455, USA
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17
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Abstract
The most reliable method for estimation of mean glomerular volume (MGV), the disector/Cavalieri method, is technically demanding and time consuming. Other methods suffer either from a lack of precise correlation with the gold standard or from the need for a large number of glomeruli in the sample. Here, a new method (the 2-profile method) is described; it provides a reliable estimate of MGV by measuring the profile area of glomeruli in two arbitrary parallel sections. MGV was estimated in renal biopsies from 16 diabetic patients and 13 normal subjects using both the Cavalieri and the 2-profile methods. The range of individual glomerular volumes based on the Cavalieri measurements was 0.31 to 4.02 x10(6) micro m(3). There was a high correlation between the two methods for MGV (r = 0.97; P < 0.0001). However, the 2-profile method systematically overestimated MGV (P = 0.0005, paired t test). This overestimation was corrected by introducing a multiplication factor of 0.91, after which statistical criteria of interchangeability with the Cavalieri method were met. The optimal distance between two sections was determined as 20 micro m with a coefficient of variation of 7.4% in repeated measurements of MGV. On the basis of findings that values for MGV stabilize after ten glomeruli are measured by the disector/Cavalieri method, it was determined that the accuracy of MGV by the 2-profile method obtained by eight glomeruli was less than 7% different from ten in all cases. Thus, the 2-profile method is a practical alternative to the disector/Cavalieri method for estimating MGV, especially in small samples and blocks with limited residual tissue.
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Affiliation(s)
- Behzad Najafian
- Department of Pediatrics, University of Minnesota, Minneapolis 55455, USA
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18
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Katz A, Caramori MLA, Sisson-Ross S, Groppoli T, Basgen JM, Mauer M. An increase in the cell component of the cortical interstitium antedates interstitial fibrosis in type 1 diabetic patients. Kidney Int 2002; 61:2058-66. [PMID: 12028446 DOI: 10.1046/j.1523-1755.2002.00370.x] [Citation(s) in RCA: 69] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
BACKGROUND Interstitial expansion is important in the progression of a variety of kidney diseases, including diabetic nephropathy (DN). However, the interstitial elements that constitute interstitial expansion in DN are unknown and are the subject of this report. METHODS Interstitial composition was analyzed in 15 long-standing type 1 diabetic patients, 8 with mild ( congruent with 1.5 x normal) and 7 with moderate ( congruent with 2 x normal) increases in cortical interstitial fractional volume [Vv(Int/cortex]. The mild group was 29 +/- 5 (mean +/- SD) years old with diabetes duration of 17 +/- 5 years. The moderate group was older (41 +/- 7 years; P < 0.03), had longer diabetes duration (28 +/- 7 years; P = 0.002), lower creatinine clearance (90 +/- 14 mL/min/1.73 m2 vs. 109 +/- 18 mL/min/1.73 m2; P = 0.05) and used antihypertensive medications more frequently (0/8 vs. 4/7; P < 0.03) compared to the mild group. Age- and gender-matched normal controls (N = 9) also were studied. Interstitial composition was evaluated by morphometric analysis of electron microscopic (EM) micrographs systematically obtained without bias at high (x 7500) and low (x 1500) magnification. RESULTS Mild interstitial expansion was associated with an congruent with 50% increase in fractional volume of interstitial cells (P < 0.001) and congruent with 70% increase in fractional volume of interstitial nuclei (P < 0.01). Numerical density of interstitial nuclei was normal in these patients, suggesting that the interstitial cells might be larger rather than simply more numerous. An increase over normal in the interstitial fractional volume of fibrillary collagen of congruent with 50% was seen only with moderate expansion (P < 0.001), when creatinine clearance was already decreased. Interstitial expansion was associated with a decrease in volume and surface of peritubular capillaries as well as with a reduction in surface ratio of capillaries to tubules. CONCLUSIONS In contrast to early mesangial expansion where matrix accumulation plays a dominant role, mild interstitial expansion in long-standing type 1 diabetic patients is largely due to an increase in the cell component of the interstitium. Increased fractional volume of interstitial fibrillary collagen is only seen at later stages of the disease, when the glomerular filtration rate is already reduced. Different pathogenetic processes may be operative in early diabetic glomerular and interstitial diseases.
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Affiliation(s)
- Avi Katz
- Department of Pediatrics, University of Minnesota, Minneapolis 55455-0392, USA
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19
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Degenhardt TP, Alderson NL, Arrington DD, Beattie RJ, Basgen JM, Steffes MW, Thorpe SR, Baynes JW. Pyridoxamine inhibits early renal disease and dyslipidemia in the streptozotocin-diabetic rat. Kidney Int 2002; 61:939-50. [PMID: 11849448 DOI: 10.1046/j.1523-1755.2002.00207.x] [Citation(s) in RCA: 293] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
BACKGROUND Nonenzymatic reactions between sugars or lipids and protein and formation of advanced glycation and lipoxidation end products (AGE/ALEs) contribute to the chemical modification and cross-linking of tissue proteins with age. Accelerated formation of AGE/ALEs during hyperglycemia is implicated in the development of diabetic complications. In this study, we examined the effect of the AGE/ALE inhibitor pyridoxamine on chemical modification and cross-linking of collagen and development of renal disease in the streptozotocin-diabetic rat. METHODS Diabetic rats were treated with pyridoxamine; parallel experiments were conducted with aminoguanidine, the prototype AGE inhibitor. Progression of renal disease was evaluated by measurements of albuminuria and plasma creatinine concentration. Plasma triglycerides, cholesterol, lactate and pyruvate were measured by enzymatic assays, and AGE/ALEs in skin collagen by HPLC and GC-MS assays. RESULTS Pyridoxamine significantly inhibited the increase in albuminuria, plasma creatinine, hyperlipidemia and plasma lactate/pyruvate ratio in diabetic rats, without an effect on blood glucose or glycated hemoglobin. AGE/ALEs, fluorescence and cross-linking of skin collagen increased approximately twofold in diabetic versus control rats after seven months of diabetes. Pyridoxamine caused a significant (25 to 50%) decrease the AGE/ALEs, carboxymethyllysine and carboxyethyllysine, cross-linking and fluorescence in skin collagen of diabetic rats, but did not affect pentosidine. CONCLUSIONS Pyridoxamine inhibits the progression of renal disease, and decreases hyperlipidemia and apparent redox imbalances in diabetic rats. Pyridoxamine and aminoguanidine had similar effects on parameters measured, supporting a mechanism of action involving AGE/ALE inhibition.
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Affiliation(s)
- Thorsten P Degenhardt
- Department of Chemistry, Animal Resource Facility, University of South Carolina, Columbia, SC 29208, USA
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Abstract
BACKGROUND The number of cells in glomeruli has been a challenging measure, especially in human kidneys, with only a small amount of tissue obtained by biopsy. However, the number of cells and their function are important determinants of renal function in health and disease. METHODS Modern morphometric techniques have now provided the means to determine the numerical density (Nv) and number (with a measure of glomerular volume) of endothelial cells, mesangial cells, and podocytes in plastic-embedded renal tissue biopsied from nondiabetic subjects (N = 36) and type 1 diabetic patients (N = 46) over an extended age range from childhood through late adult. RESULTS Nv values for all glomerular cells varied only slightly with age and did not change within the range of glomerular lesions of diabetes studied. Thus, the increase in glomerular volume during childhood to a steady level thereafter was the primary determinant of total glomerular cell number. The number of mesangial cells and endothelial cells increased with age, reflecting the increase in all cells, while the podocytes remained unchanged in number over all ages studied (10 to 69 years). Numbers of total glomerular cells, mesangial cells, and endothelial cells were not changed with diabetes, while podocytes were fewer in number in diabetic patients of all ages, with reduced podocyte numbers even in diabetes of short duration. CONCLUSIONS The essentially constant glomerular cell density in nondiabetic and diabetic subjects under different circumstances possibly indicates an underlying propensity for the glomerulus to regulate its architecture to maintain a constant number of cells per volume, no matter the size of the glomerulus or the severity of diabetic nephropathy studied in this set of patients. The reductions in podocyte numbers in both younger and older diabetic patients indicate a significant risk for functional abnormalities as diabetic nephropathy progresses. Moreover, these observations do not support the suggestion of marked increases in glomerular cell number (and especially mesangial cells) with the development and progression of diabetic nephropathy.
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Affiliation(s)
- M W Steffes
- Department of Laboratory Medicine and Pathology, University of Minnesota Medical School, Minneapolis, Minnesota, USA.
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Basgen JM, Mauer M. Accuracy of methods used to quantify cell hyperplasia. Kidney Int 2001; 59:384-5. [PMID: 11135098 DOI: 10.1046/j.1523-1755.2001.00503.x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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Brito PL, Fioretto P, Drummond K, Kim Y, Steffes MW, Basgen JM, Sisson-Ross S, Mauer M. Proximal tubular basement membrane width in insulin-dependent diabetes mellitus. Kidney Int 1998; 53:754-61. [PMID: 9507223 DOI: 10.1046/j.1523-1755.1998.00809.x] [Citation(s) in RCA: 101] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Although glomerular structure has been studied, careful evaluation of tubular basement membrane (TBM) structure in diabetes in humans has not been done. We measured proximal TBM width, glomerular basement membrane (GBM) width, mesangial fractional volume [Vv(Mes/glom)], mesangial matrix fractional volume [Vv(MM/glom)], and cortical interstitial fractional volume [Vv(Int/cortex)] in 35 insulin-dependent diabetic (IDDM) patients and 20 controls. The patients' mean age was 28 +/- 10 years (X +/- SD) and IDDM duration was 17 +/- 8 years. Twenty-five patients were normoalbuminuric, four microalbuminuric, and six had overt proteinuria. Tubular basement membrane and GBM widths were measured by the orthogonal intercept method and mesangial and interstitial parameters by point counting. The TBM width was 915 +/- 320 nm in IDDM patients and 558 +/- 116 nm in controls (P = 0.0005); the TBM width was also increased in normoalbuminuric patients (849 +/- 297 nm, P = 0.0005). The TBM width was strongly directly related to GBM width (r = 0.67, P < 0.001), Vv(Mes/glom) (r = 0.52, P < 0.01), and Vv(MM/glom) (r = 0.61, P < 0.001), but only weakly to Vv(Int/cortex) (r = 0.29, NS). The TBM width (r = 0.65, P < 0.001) and GBM width (r = 0.65, P < 0.001) were strongly related to hemoglobin A1C (HbA1C), while the Vv(Mes/glom) (r = 0.35, P < 0.05) and Vv(Int/cortex) (r = 0.30, NS) were only weakly related to HbA1C. Thus, increased proximal TBM width is an integral component of early nephropathology in IDDM patients. This study suggests that the metabolic disturbances of diabetes are strong determinants of the constellation of structural abnormalities occurring in human diabetic nephropathy.
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Affiliation(s)
- P L Brito
- Department of Pediatrics, University of Minnesota, Minneapolis, USA
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Abstract
In the past researchers have used an estimate of one million as the number of glomeruli in each human kidney. However, recent work on excised kidneys has demonstrated a large variation in glomerular number from one person to another (330,000 to 1,400,000) per kidney. Theoretically an in situ estimate of glomerular number could be obtained if renal cortical volume, volume density of glomeruli per cortex [Vv(glom/cortex)] and mean glomerular volume are known. We used a dog model to demonstrate that an accurate estimate of cortical volume could be obtained in situ using magnetic resonance imaging (MRI). Vv(glom/cortex) and mean glomerular volume were obtained from needle biopsies. An independent and more direct method (the fractionator) was used to validate the estimate of glomerular number obtained using MRI and renal biopsy. On average there was very good agreement between the fractionator method (379,000 +/- 40,000) and the MRI/renal biopsy method (376,000 +/- 108,000) for the 10 dog kidneys measured; however we found up to a 36% difference between the two methods in an individual kidney. Nonetheless, the estimate from the MRI/renal biopsy method has more precision than the assumption that there are one million glomeruli per human kidney.
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Affiliation(s)
- J M Basgen
- University of Minnesota Medical School, Minneapolis
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Abstract
A method is described to measure antigen(s) in tissue section using an image analysis system to quantitate immunofluorescence following staining with fluorescein isothiocyanate (FITC)-conjugated antibody. The antigen utilized was an 125I-labeled goat anti-glomerular basement membrane antibody (1409 cpm/micrograms) administered intravenously to each of 11 Sprague-Dawley rats in doses ranging from 1.09 to 34.72 mg IgG. 24 h later, both kidneys were obtained for quantitative immunofluorescence following staining of tissue sections with FITC-labeled rabbit anti-goat IgG and for determination of radioactivity which reflects the amount of goat IgG present in isolated glomeruli. A linear correlation (r = 0.97) was observed between the dose of administered goat 125I-IgG and the amount bound to isolated glomeruli over the entire dosage range. A highly significant correlation (r = 0.98) was also seen between the mean brightness per glomerulus as determined by quantitative immunofluorescence and the amount of 125I-IgG bound per glomerulus but only at values less than 500 pg of IgG per glomerulus. Above these levels no correlation was observed, suggesting the presence of hidden epitopes in the bound goat IgG or the lack of availability of the FITC-labeled rabbit antibody.
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Affiliation(s)
- J M Basgen
- Department of Pediatrics, University of Minnesota Medical School 55455
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Abstract
Volume density (Vv) is a morphometric parameter used to detect pathological changes within renal tissue. To establish the most efficient technique, Vv of the mesangium in renal biopsies was studied. First, a digitizing tablet was used to trace mesangial and total glomerular areas, subsequently used to calculate Vv of the mesangium. Secondly, a point counting technique was tested using either a 16-point or an 81-point grid; the number of grid points falling on the mesangium and glomerulus was used to calculate mesangial Vv. The digitizing tablet, the 81-point grid and the 16-point grid all gave equivalent Vv for the 15 biopsies. The 81-point grid and the 16-point grid were, respectively, 1.9 and 3.2-fold faster than the digitizing tablet. Since all techniques gave comparable results, the 16-point grid was the most efficient.
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Affiliation(s)
- J M Basgen
- Department of Pediatrics, University of Minnesota Hospital and Clinic, Minneapolis
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Affiliation(s)
- R W Bilous
- Department of Laboratory Medicine, University of Minnesota, Minneapolis
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Nevins TE, Gaston T, Basgen JM. Quantitative indexes of aminonucleoside-induced nephrotic syndrome. Am J Pathol 1984; 117:30-6. [PMID: 6486243 PMCID: PMC1900560] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Grants] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
Aminonucleoside of puromycin (PAN) is known to cause altered glomerular permeability, resulting in a nephrotic syndrome in rats. The early sequence of this lesion was studied quantitatively, with the application of a new morphometric technique for determining epithelial foot process widths and a sensitive assay for quantifying urinary albumin excretion. Twenty-four hours following a single intraperitoneal injection of PAN, significant widening of foot processes was documented. Within 36 hours significant increases in urinary albumin excretion were observed. When control rats were examined, there was no clear correlation between epithelial foot process width and quantitative albumin excretion. However, in the PAN-treated animals, abnormal albuminuria only appeared in association with appreciable foot process expansion. These studies indicate that quantitative alterations occur in the rat glomerular capillary wall as early as 24 hours after PAN. Further studies of altered glomerular permeability may use these sensitive measures to more precisely define the temporal sequence and elucidate possible subgroups of experimental glomerular injury.
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Steffes MW, Barbosa J, Basgen JM, Sutherland DE, Najarian JS, Mauer SM. Quantitative glomerular morphology of the normal human kidney. J Transl Med 1983; 49:82-6. [PMID: 6865334] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
We determined glomerular basement membrane (GBM) width (as the harmonic mean) and relative volumes of the glomerular mesangium and of its cellular and matrix components in 59 male (73% living-related) and 59 female (93% living-related) donors of kidneys for transplantation. The GBM, consistently wider in male (mean, 373 nm.) versus female (mean, 326 nm.) donors, increased in width in all donors until the fourth decade of life when it appeared to decrease in width. The relative volume of the mesangium did not differ as to sex or age (mean, 14.2% of the glomerular volume), nor did either of its components (mean cellular mesangium, 7.1%; mean matrix mesangium, 7.1%). We found no correlations among renal index, GBM width, or the mesangium. No parameter differed in diabetic-related compared with nondiabetic-related donors. Results in cadavers for GBM width and the mesangium were no different from those of living-related donors. These observations yield insights into the development of the human kidney and its glomerular components, and in addition the GBM and mesangial measures will serve as normative values to which surgical or biopsy specimens can be related.
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Steffes MW, Vernier RL, Brown DM, Basgen JM, Mauer SM. Diabetic glomerulopathy in the uninephrectomized rat resists amelioration following islet transplantation. Diabetologia 1982; 23:347-53. [PMID: 6814977 DOI: 10.1007/bf00253743] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
Uninephrectomy is known to accelerate the development of both functional and morphological changes seen with experimental diabetic nephropathy in the rat. The present experiments utilized electron and light microscopic morphometric techniques to assess glomerular basement membrane width and the volumes of the total mesangium and its cellular and matrix components of inbred Lewis rats made diabetic at 6 weeks of age and uninephrectomized 9 days later. Immunofluorescent microscopy was used to evaluate IgG and C3 in the mesangium. The reversibility of established diabetic glomerular lesions in uninephrectomized diabetic rats after 7 months of diabetes was studied by performing intraportal transplant of neonatal pancreatic tissue. Renal biopsies were taken 2 months later in transplanted and non-transplanted animals. Islet transplantation lowered plasma glucose to normal levels (29.6 to 7.3 mmol/l) and raised plasma insulin values (6.3 to 53 muU/I). Glomerular basement membrane width in transplanted rats (268 nm) still exceeded the same measure (226 nm) in nondiabetic uninephrectomized rats. In transplanted animals volumes of the mesangium (0.51 x 10(6) micrometers 3) and of its cellular (0.27 x 10(6) micrometers 3) and matrix (0.24 x 10(6) micrometers 3) components remained higher than similar measures in control rats (0.32 x 10(6), 0.17 x 10(6) and 0.15 x 10(6) micrometers 3, respectively). Mesangial IgG in treated animals approached normal, but mesangial C3 remained similar to levels in non-transplanted diabetic control animals. These observations in uninephrectomized-diabetic rats contrast with previous observations in intact diabetic rats in which mesangial volumes and localization of immunoglobulins and complement returned to normal levels following islet transplantation.
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Steffes MW, Leffert JD, Basgen JM, Brown DM, Mauer SM. Epithelia cell foot process width in intact and uninephrectomized diabetic and nondiabetic rats. J Transl Med 1980; 43:225-30. [PMID: 6447233] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
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Abstract
Highly inbred Lewis rats with streptozotocin-induced diabetes mellitus of 7 mo duration received intraportal transplants of neonatal pancreatic tissue. At 7 and 9 mo of diabetes (at the time of and at 2 mo after islet transplantation) renal biopsies for the evaluation of several morphometric parameters were obtained from control (C), diabetic-nontranspianted (D), and diabetic-transplanted (D-T: with normal plasma glucose values) rats.
Glomerular volume in D-T animals at 9 mo fell to a value less than that in C rats while glomerular volume in D animals exceeded that in C rats at both 7 and 9 mo. Electron microscopic morphometry of the total mesangium and its cellular and matrix components documented a nearly twofold increase in the volume of the mesangial matrix in D as compared with C rats at both 7 and 9 mo. While the mesangial cellular component was also increased in diabetes, the changes in the volume of the mesangial matrix in D rats at both 7 and 9 mo provided the major proportion of the increased volume of the total mesangium. With islet transplantation, significant reduction in the volumes of the mesangial matrix and a much smaller and not significant decrease in the cellular component gave normal values for those components and for the volume of the total mesangium in D-T animals.
The expanded volume of the total mesangium in diabetes concomitantly increased the proportion of the glomerular capillary surface interfaced with the mesangium. Similarly, the proportion of the glomerular basement membrane (GBM)-epithelium interface juxtaposed to the mesangium was elevated in diabetes. These two observations imply that the expanding mesangium interposed itself between the endothelial cells and the GBM, increasing the surface of the mesangium. With islet transplantation these surface alterations returned toward normal in conjunction with the reduction in volume of the mesangium.
These observations with electron microscopic morphometry provide detailed documentation of the alterations in the mesangium of experimental diabetes mellitus. The sensitivity with which these changes can be monitored permit detailed analysis of subtle increases in both mesangial surface and volume in diabetes mellitus.
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Steffes MW, Brown DM, Basgen JM, Matas AJ, Mauer SM. Glomerular basement membrane thickness following islet transplantation in the diabetic rat. Lab Invest 1979; 41:116-8. [PMID: 110982] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Glomerular basement membrane (GBM) thickness was measured in diabetic rats prior to and following islet transplantation. Over the course of the experiment (from 7 to 13 months of diabetes) GBM thickness in diabetic animals exceeded that of littermate controls. After 7 months of diabetes a group of animals received successful intraportal transplants of neonatal pancreatic tissue. GBM thickness at 2 and 6 months following islet transplantation matched the thickness in nontransplanted diabetic rats and exceeded that in control animals. Failure to reverse GBM thickening in diabetic rats following islet transplantation may be due to very slow rates of GBM tunover in the rat. Previous work has demonstrated normalization of urinary albumin excretion after islet transplantation, suggesting that GBM thickening, per se, is not a significant factor causing albuminuria in rats with longstanding diabetes.
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