101
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Conway BR, Betz B, Sheldrake TA, Manning JR, Dunbar DR, Dobyns A, Hughes J, Mullins JJ. Tight blood glycaemic and blood pressure control in experimental diabetic nephropathy reduces extracellular matrix production without regression of fibrosis. Nephrology (Carlton) 2015; 19:802-13. [PMID: 25196678 DOI: 10.1111/nep.12335] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/01/2014] [Indexed: 01/15/2023]
Abstract
AIMS Regression of albuminuria and renal fibrosis occurs in patients with diabetic nephropathy (DN) following tight control of blood glucose and blood pressure, however the pathways that promote regression remain poorly understood and we wished to characterize these using a rodent model. METHODS Diabetes was induced with streptozotocin in Cyp1a1mRen2 rats and hypertension was generated by inducing renin transgene expression with dietary indole-3-carbinol (I-3-C) for 28 weeks. At this point an 'injury cohort' was culled, while in a 'reversal cohort' glycaemia was tightly controlled using insulin implants and blood pressure normalized by withdrawing dietary I-3-C for a further 8 weeks. Pathways activated during and following reversal of diabetes and hypertension were assessed by microarray profiling. RESULTS Tight control of blood glucose and blood pressure reduced albuminuria and renal hypertrophy, but had no impact on renal fibrosis. 85 genes were up-regulated specifically during the injury phase, including genes encoding multiple myofibroblast and extracellular matrix (ECM) proteins. Conversely, 314 genes remained persistently elevated during reversal including genes linked to innate/adaptive immunity, phagocytosis, lysosomal processing and degradative metalloproteinases (MMPs). Despite increased MMP gene expression, MMP activity was suppressed during both injury and reversal, in association with up-regulation of tissue inhibitor of metalloproteinase-1 (TIMP-1) protein. Physical separation of the TIMP-1/MMP complexes during zymography of tissue homogenate restored MMP activity. CONCLUSION Normalization of blood glucose and pressure ameliorates albuminuria and inhibits excess ECM production, however persistent TIMP-1 expression hinders attempts at ECM remodelling. Therapies which counteract the action of TIMPs may accelerate scar resolution.
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Affiliation(s)
- Bryan R Conway
- Centre for Cardiovascular Science, British Heart Foundation/University of Edinburgh, Edinburgh, UK
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102
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Marchant V, Droguett A, Valderrama G, Burgos ME, Carpio D, Kerr B, Ruiz-Ortega M, Egido J, Mezzano S. Tubular overexpression of Gremlin in transgenic mice aggravates renal damage in diabetic nephropathy. Am J Physiol Renal Physiol 2015; 309:F559-68. [PMID: 26155842 DOI: 10.1152/ajprenal.00023.2015] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2015] [Accepted: 06/30/2015] [Indexed: 12/12/2022] Open
Abstract
Diabetic nephropathy (DN) is currently a leading cause of end-stage renal failure worldwide. Gremlin was identified as a gene differentially expressed in mesangial cells exposed to high glucose and in experimental diabetic kidneys. We have described that Gremlin is highly expressed in biopsies from patients with diabetic nephropathy, predominantly in areas of tubulointerstitial fibrosis. In streptozotocin (STZ)-induced experimental diabetes, Gremlin deletion using Grem1 heterozygous knockout mice or by gene silencing, ameliorates renal damage. To study the in vivo role of Gremlin in renal damage, we developed a diabetic model induced by STZ in transgenic (TG) mice expressing human Gremlin in proximal tubular epithelial cells. The albuminuria/creatinuria ratio, determined at week 20 after treatment, was significantly increased in diabetic mice but with no significant differences between transgenic (TG/STZ) and wild-type mice (WT/STZ). To assess the level of renal damage, kidney tissue was analyzed by light microscopy (periodic acid-Schiff and Masson staining), electron microscopy, and quantitative PCR. TG/STZ mice had significantly greater thickening of the glomerular basement membrane, increased mesangial matrix, and podocytopenia vs. WT/STZ. At the tubulointerstitial level, TG/STZ showed increased cell infiltration and mild interstitial fibrosis. In addition, we observed a decreased expression of podocin and overexpression of monocyte chemoattractant protein-1 and fibrotic-related markers, including transforming growth factor-β1, Col1a1, and α-smooth muscle actin. Together, these results show that TG mice overexpressing Gremlin in renal tubules develop greater glomerular and tubulointerstitial injury in response to diabetic-mediated damage and support the involvement of Gremlin in diabetic nephropathy.
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Affiliation(s)
- Vanessa Marchant
- Nephrology Division, School of Medicine, Universidad Austral de Chile, Valdivia, Chile
| | - Alejandra Droguett
- Nephrology Division, School of Medicine, Universidad Austral de Chile, Valdivia, Chile
| | - Graciela Valderrama
- Nephrology Division, School of Medicine, Universidad Austral de Chile, Valdivia, Chile
| | - M Eugenia Burgos
- Nephrology Division, School of Medicine, Universidad Austral de Chile, Valdivia, Chile
| | - Daniel Carpio
- Nephrology Division, School of Medicine, Universidad Austral de Chile, Valdivia, Chile
| | | | - Marta Ruiz-Ortega
- Cellular Biology in Renal Diseases Laboratory, Universidad Autónoma de Madrid (UAM), Instituto de Investigación Sanitaria (IIS)-Fundación Jimenez Diaz, Madrid, Spain; and
| | - Jesús Egido
- Division of Nephrology and Hypertension, IIS-Fundación Jiménez Díaz-UAM/Centro de Investigación Biomédica en Red de Diabetes y Enfermedades Metabólicas Asociadas, Instituto Reina Sofía de Investigación Nefrológica, Madrid, Spain
| | - Sergio Mezzano
- Nephrology Division, School of Medicine, Universidad Austral de Chile, Valdivia, Chile;
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103
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Stefanska A, Eng D, Kaverina N, Duffield JS, Pippin JW, Rabinovitch P, Shankland SJ. Interstitial pericytes decrease in aged mouse kidneys. Aging (Albany NY) 2015; 7:370-82. [PMID: 26081073 PMCID: PMC4505164 DOI: 10.18632/aging.100756] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/15/2023]
Abstract
With increasing age, the kidney undergoes characteristic changes in the glomerular and tubulo-interstitial compartments, which are ultimately accompanied by reduced kidney function. Studies have shown age-related loss of peritubular vessels. Normal peritubular vessel tone, function and survival depend on neighboring pericytes. Pericyte detachment leads to vascular damage, which can be accompanied by their differentiation to fibroblasts and myofibroblasts, a state that favors matrix production. To better understand the fate of pericytes in the aged kidney, 27 month-old mice were studied. Compared to 3 month-old young adult mice, aged kidneys showed a substantial decrease in capillaries, identified by CD31 staining, in both cortex and medulla. This was accompanied by a marked decrease in surrounding NG2+ / PDGFRβ+ pericytes. This decrease was more pronounced in the medulla. Capillaries devoid of pericytes were typically dilated in aged mice. Aged kidneys were also characterized by interstitial fibrosis due to increased collagen-I and -III staining. This was accompanied by an increase in the number of pericytes that acquired a pro-fibrotic phenotype, identified by increased PDGFRβ+ / αSMA+ staining. These findings are consistent with the decline in kidney interstitial pericytes as a critical step in the development of changes to the peritubular vasculature with aging, and accompanying fibrosis.
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Affiliation(s)
- Ania Stefanska
- Division of Nephrology, Department of Medicine, University of Washington, Seattle, WA 98104, USA
| | - Diana Eng
- Division of Nephrology, Department of Medicine, University of Washington, Seattle, WA 98104, USA
| | - Natalya Kaverina
- Division of Nephrology, Department of Medicine, University of Washington, Seattle, WA 98104, USA
| | - Jeremy S. Duffield
- Division of Nephrology, Department of Medicine, University of Washington, Seattle, WA 98104, USA
- Biogen Idec, Cambridge, MA 02142, USA
| | - Jeffrey W. Pippin
- Division of Nephrology, Department of Medicine, University of Washington, Seattle, WA 98104, USA
| | - Peter Rabinovitch
- Department of Pathology, University of Washington, Seattle, WA 98195, USA
| | - Stuart J. Shankland
- Division of Nephrology, Department of Medicine, University of Washington, Seattle, WA 98104, USA
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104
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Glomerular parietal epithelial cells contribute to adult podocyte regeneration in experimental focal segmental glomerulosclerosis. Kidney Int 2015; 88:999-1012. [PMID: 25993321 PMCID: PMC4654724 DOI: 10.1038/ki.2015.152] [Citation(s) in RCA: 102] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2014] [Revised: 04/01/2015] [Accepted: 04/02/2015] [Indexed: 01/02/2023]
Abstract
Since adult podocytes cannot adequately proliferate following depletion in disease states there has been interest in the potential role of progenitors in podocyte repair and regeneration. To determine if parietal epithelial cells (PECs) can serve as adult podocyte progenitors following disease-induced podocyte depletion, PECs were permanently labeled in adult PECrtTA/LC1/R26 reporter mice. In normal mice, labeled PECs were confined to Bowman's capsule, while in disease (cytotoxic sheep anti-podocyte antibody), labeled PECs were found in the glomerular tuft in progressively higher numbers by days 7, 14 and 28. Early in disease, the majority of PECs in the tuft co-expressed CD44. By day 28, when podocyte numbers were significantly higher and disease severity was significantly lower, the majority of labeled PECs co-expressed podocyte proteins but not CD44. Neither labeled PECs on the tuft, nor podocytes stained for the proliferation marker BrdU. The de novo expression of phospho-ERK colocalized to CD44 expressing PECs, but not to PECs expressing podocyte markers. Thus, in a mouse model of focal segmental glomerulosclerosis typified by abrupt podocyte depletion followed by regeneration, PECs undergo two phenotypic changes once they migrate to the glomerular tuft. Initially these cells are predominantly activated CD44 expressing cells coinciding with glomerulosclerosis, and later they predominantly exhibit a podocyte phenotype which is likely reparative.
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105
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Wang ZS, Xiong F, Xie XH, Chen D, Pan JH, Cheng L. Astragaloside IV attenuates proteinuria in streptozotocin-induced diabetic nephropathy via the inhibition of endoplasmic reticulum stress. BMC Nephrol 2015; 16:44. [PMID: 25886386 PMCID: PMC4387678 DOI: 10.1186/s12882-015-0031-7] [Citation(s) in RCA: 74] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2014] [Accepted: 03/12/2015] [Indexed: 12/20/2022] Open
Abstract
Background Diabetic nephropathy (DN) is a major cause of Chronic Kidney Disease and End-Stage Renal Disease throughout the world; however, the reversibility of diabetic nephropathy remains controversial. Endoplasmic reticulum (ER) stress plays an important role in the pathogenesis of DN. Astragaloside IV (AS-IV) is derived from Astragalus membranaceus (Fisch) Bge, a widely used traditional herbal medicine in China, and has diverse pharmacological activities including the attenuation of podocyte injury and amelioration of proteinuria in idiopathic nephrotic syndrome. The present study aimed to investigate the effect and mechanism of AS-IV on proteinuria in the rat streptozotocin (STZ)-induced model of diabetes. Methods Male Sprague–Dawley (SD) rats were randomly divided into four groups: normal control (Normal group), diabetic nephropathy (Model group), diabetic nephropathy plus AS-IV treatment (AS-IV group) and diabetic nephropathy plus 4-phenyl butyric acid treatment (PBA group). ER stress was induced in cultured human podocytes, pretreated with or without AS-IV, with tunicamycin (TM). At the end of 8 weeks, serum creatinine (Scr), blood urea nitrogen (BUN) and 24-hour urinary protein excretion rate (UAER) were determined. Renal morphology was examined after periodic acid-Schiff staining of kidney sections. Apoptosis of podocytes was measured by flow cytometry. The total expression and phosphorylation of eIF2α, PERK and JNK, and the expression of CHOP and cleaved caspase-3 were determined by western blotting. The expression of glucose-regulated protein 78 (GRP78) and 150 kDa oxygen-regulated protein (ORP150) mRNA and protein was determined by real-time PCR and western blotting respectively. Results AS-IV treatment significantly reduced urinary albumin excretion, plasma creatinine and blood urea nitrogen levels, and prevented the mesangial matrix expansion and increase in mean mesangial induced by STZ. AS-IV also prevented the phosphorylation of eIF2α, PERK and JNK, and inhibited the expression of GRP78 and ORP150 markedly, both in vivo and in vitro. AS-IV inhibited the TM-induced apoptosis of podocytes, concomitant with decreased CHOP expression and cleaved caspase-3. Conclusions This study supports the hypothesis that AS-IV reduces proteinuria and attenuates diabetes, which is associated with decreased ER stress. This might be an important mechanism in the renoprotective function of AS-IV in the pathogenesis of DN.
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Affiliation(s)
- Zeng Si Wang
- Department of Nephrology, Wuhan No.1 Hospital, Wuhan, 430000, Hubei Province, PR China.
| | - Fei Xiong
- Department of Nephrology, Wuhan No.1 Hospital, Wuhan, 430000, Hubei Province, PR China.
| | - Xiao Hang Xie
- Department of Nephrology, Wuhan No.1 Hospital, Wuhan, 430000, Hubei Province, PR China.
| | - Dan Chen
- Department of Nephrology, Wuhan No.1 Hospital, Wuhan, 430000, Hubei Province, PR China.
| | - Jian Hua Pan
- Department of Nephrology, Wuhan No.1 Hospital, Wuhan, 430000, Hubei Province, PR China.
| | - Li Cheng
- Department of Nephrology, Wuhan No.1 Hospital, Wuhan, 430000, Hubei Province, PR China.
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106
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New insights into glomerular parietal epithelial cell activation and its signaling pathways in glomerular diseases. BIOMED RESEARCH INTERNATIONAL 2015; 2015:318935. [PMID: 25866774 PMCID: PMC4383425 DOI: 10.1155/2015/318935] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 05/23/2014] [Revised: 07/28/2014] [Accepted: 09/01/2014] [Indexed: 12/26/2022]
Abstract
The glomerular parietal epithelial cells (PECs) have aroused an increasing attention recently. The proliferation of PECs is the main feature of crescentic glomerulonephritis; besides that, in the past decade, PEC activation has been identified in several types of noninflammatory glomerulonephropathies, such as focal segmental glomerulosclerosis, diabetic glomerulopathy, and membranous nephropathy. The pathogenesis of PEC activation is poorly understood; however, a few studies delicately elucidate the potential mechanisms and signaling pathways implicated in these processes. In this review we will focus on the latest observations and concepts about PEC activation in glomerular diseases and the newest identified signaling pathways in PEC activation.
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107
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Glomerular parietal epithelial cell activation induces collagen secretion and thickening of Bowman's capsule in diabetes. J Transl Med 2015; 95:273-82. [PMID: 25531564 DOI: 10.1038/labinvest.2014.160] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2014] [Revised: 09/27/2014] [Accepted: 11/05/2014] [Indexed: 02/06/2023] Open
Abstract
The metabolic and hemodynamic alterations in diabetes activate podocytes to increase extracellular matrix (ECM) production, leading to thickening of the glomerular basement membrane (GBM). We hypothesized that diabetes would activate parietal epithelial cells (PECs) in a similar manner and cause thickening of Bowman's capsules. Periodic acid Schiff staining of human kidney biopsies of 30 patients with diabetic nephropathy (DN) revealed a significantly thicker Bowman's capsule as compared with 20 non-diabetic controls. The average thickness was 4.55±0.21 μm in the group of patients with DN compared with 2.92±0.21 μm in the group of non-diabetic controls (P<0.001). Transmission electron microscopy confirmed this finding. In vitro, short-term exposure of human PECs to hyperglycemic conditions (30 mM glucose) advanced glycation end products (100 μg/ml) or transforming growth factor-β1 (TGF-β1; 5 ng/ml) increased the mRNA expression of collagen type I α-1, collagen type IV (all six α-chains), bamacan, nidogen 1, laminin α-1, and perlecan. Western blot and colorimetric collagen assays confirmed these results for collagen type IV at the protein level. The production and secretion of TGF-β1 as a possible positive feedback loop was excluded as a mechanism for the autocrine activation of human PECs. To validate these findings in vivo, activation of the PECs was assessed by immunohistochemical staining for CD44 of 12 human biopsy cases with DN. Thickening of the Bowman's capsule showed strong association with CD44-positive PECs. In summary, metabolic alterations in diabetes activate PECs to increase the expression and secretion of Bowman's capsule proteins. This process may contribute to the thickening of the Bowman's capsule, similar to the thickening of the GBM that is driven by activated podocytes. These data may also imply that activated PECs contribute to ECM production once they migrate to the glomerular tuft, a process resulting in glomerular scaring, for example, in diabetic glomerulosclerosis.
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108
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Putting the glomerulus back together: per aspera ad astra ("a rough road leads to the stars"). Kidney Int 2015; 85:991-8. [PMID: 24786868 DOI: 10.1038/ki.2014.51] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
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109
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Puelles VG, Douglas-Denton RN, Cullen-McEwen LA, Li J, Hughson MD, Hoy WE, Kerr PG, Bertram JF. Podocyte Number in Children and Adults: Associations with Glomerular Size and Numbers of Other Glomerular Resident Cells. J Am Soc Nephrol 2015; 26:2277-88. [PMID: 25568174 DOI: 10.1681/asn.2014070641] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2014] [Accepted: 11/02/2014] [Indexed: 11/03/2022] Open
Abstract
Increases in glomerular size occur with normal body growth and in many pathologic conditions. In this study, we determined associations between glomerular size and numbers of glomerular resident cells, with a particular focus on podocytes. Kidneys from 16 male Caucasian-Americans without overt renal disease, including 4 children (≤3 years old) to define baseline values of early life and 12 adults (≥18 years old), were collected at autopsy in Jackson, Mississippi. We used a combination of immunohistochemistry, confocal microscopy, and design-based stereology to estimate individual glomerular volume (IGV) and numbers of podocytes, nonepithelial cells (NECs; tuft cells other than podocytes), and parietal epithelial cells (PECs). Podocyte density was calculated. Data are reported as medians and interquartile ranges (IQRs). Glomeruli from children were small and contained 452 podocytes (IQR=335-502), 389 NECs (IQR=265-498), and 146 PECs (IQR=111-206). Adult glomeruli contained significantly more cells than glomeruli from children, including 558 podocytes (IQR=431-746; P<0.01), 1383 NECs (IQR=998-2042; P<0.001), and 367 PECs (IQR=309-673; P<0.001). However, large adult glomeruli showed markedly lower podocyte density (183 podocytes per 10(6) µm(3)) than small glomeruli from adults and children (932 podocytes per 10(6) µm(3); P<0.001). In conclusion, large adult glomeruli contained more podocytes than small glomeruli from children and adults, raising questions about the origin of these podocytes. The increased number of podocytes in large glomeruli does not match the increase in glomerular size observed in adults, resulting in relative podocyte depletion. This may render hypertrophic glomeruli susceptible to pathology.
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Affiliation(s)
- Victor G Puelles
- Department of Anatomy and Developmental Biology, Monash University, Melbourne, Australia
| | | | - Luise A Cullen-McEwen
- Department of Anatomy and Developmental Biology, Monash University, Melbourne, Australia
| | - Jinhua Li
- Department of Anatomy and Developmental Biology, Monash University, Melbourne, Australia
| | - Michael D Hughson
- Department of Pathology, University of Mississippi Medical Center, Jackson, Mississippi
| | - Wendy E Hoy
- Centre for Chronic Disease, The University of Queensland, Brisbane, Australia
| | - Peter G Kerr
- Department of Nephrology, Monash Medical Centre, Melbourne, Australia; and Department of Medicine, Monash University, Melbourne, Australia
| | - John F Bertram
- Department of Anatomy and Developmental Biology, Monash University, Melbourne, Australia;
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Xiong X, Mei W, Xie Y, Liu J, Lu M, Peng X, Yang C, Zhang X, Xie M, Luo R, Yuan X, Huang L, Wu L, Qin J, Peng Y, Jia X, Hu G, Tang D, Tao L. Fluorofenidone offers improved renoprotection at early interventions during the course of diabetic nephropathy in db/db mice via multiple pathways. PLoS One 2014; 9:e111242. [PMID: 25347392 PMCID: PMC4210223 DOI: 10.1371/journal.pone.0111242] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2013] [Accepted: 09/30/2014] [Indexed: 11/19/2022] Open
Abstract
Diabetic nephropathy (DN) remains the leading cause of end-stage renal disease (ESRD), a situation that is in part attributable to the lack of effective treatments. Fluorofenidone is a newly developed reagent with anti-fibrotic activity. While fluorofenidone was previously demonstrated to possess renoprotection from DN pathogenesis in db/db mice, the protective process and its underlying mechanisms have not been well studied. To characterize fluorofenidone-derived renoprotection, we treated 5, 8, or 12-week old db/db mice with daily doses of placebo, fluorofenidone, or losartan until 24 weeks of age; the time at which diabetes and DN were fully developed in placebo-treated animals. In comparison to db/db mice receiving fluorofenidone at 12-weeks old, those treated at 5-weeks had less glomerular expansion and better preservation of renal functions, judged by serum creatinine levels, albumin to creatinine ratio, and urinary albumin excretion (mg/24 hours). These benefits of early treatment were associated with significant reductions of multiple DN-promoting events, such as decreased expression of TGF-β1 and the p22phox subunit of NADPH oxidase as well as downregulated activation of protein kinase C-zeta (ζ), ERK and AKT. This improvement in renoprotection following early interventions is not a unique property of DN pathogenesis, as losartan does not apparently offer the same benefits and is not more renoprotective than fluorofenidone. Additionally, the enhanced renoprotection provided by fluorofenidone did not affect the diabetic process, as it did not alter serum levels of glycated serum proteins, glucose, triglyceride or cholesterol. Collectively, we provide evidence that fluorofenidone offers improved renoprotection at early stages of DN pathogenesis.
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Affiliation(s)
- Xuan Xiong
- Division of Nephrology, Xiangya Hospital, Central South University, Changsha, Hunan, China
| | - Wenjuan Mei
- Division of Nephrology, Xiangya Hospital, Central South University, Changsha, Hunan, China
| | - Yanyun Xie
- Division of Nephrology, Xiangya Hospital, Central South University, Changsha, Hunan, China
- Division of Nephrology, Department of Medicine, McMaster University, Hamilton, Ontario, Canada
| | - Jishi Liu
- Department of Nephrology, The Third Xiangya Hospital, Changsha, Hunan, China
| | - Miaomiao Lu
- Division of Nephrology, Xiangya Hospital, Central South University, Changsha, Hunan, China
| | - Xiongqun Peng
- Department of Gastroenterology, Xiangya Hospital, Changsha, Hunan, China
| | - Congyin Yang
- Department of Gastroenterology, Xiangya Hospital, Changsha, Hunan, China
| | - Xin Zhang
- Department of Gastroenterology, Xiangya Hospital, Changsha, Hunan, China
| | - Mingyan Xie
- Department of Gastroenterology, Xiangya Hospital, Changsha, Hunan, China
| | - Renna Luo
- Division of Nephrology, Xiangya Hospital, Central South University, Changsha, Hunan, China
| | - Xiangning Yuan
- Division of Nephrology, Xiangya Hospital, Central South University, Changsha, Hunan, China
| | - Ling Huang
- Division of Nephrology, Xiangya Hospital, Central South University, Changsha, Hunan, China
| | - Lin Wu
- Division of Nephrology, Xiangya Hospital, Central South University, Changsha, Hunan, China
| | - Jiao Qin
- Division of Nephrology, Xiangya Hospital, Central South University, Changsha, Hunan, China
| | - Yu Peng
- Division of Nephrology, Xiangya Hospital, Central South University, Changsha, Hunan, China
| | - Xiujie Jia
- Department of Respiratory Medicine, The second Xiangya Hospital, Changsha, Hunan, China
| | - Gaoyun Hu
- Chemistry Section, Department of Medicinal Chemistry, School of Pharmaceutical Sciences, Central South University, Changsha, Hunan, China
| | - Damu Tang
- Division of Nephrology, Department of Medicine, McMaster University, Hamilton, Ontario, Canada
- * E-mail: (DT); (LT)
| | - Lijian Tao
- Division of Nephrology, Xiangya Hospital, Central South University, Changsha, Hunan, China
- State Key Laboratory of Medical Genetics of China, Central South University, Changsha, Hunan, China
- * E-mail: (DT); (LT)
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Márquez E, Riera M, Pascual J, Soler MJ. Renin-angiotensin system within the diabetic podocyte. Am J Physiol Renal Physiol 2014; 308:F1-10. [PMID: 25339703 DOI: 10.1152/ajprenal.00531.2013] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Diabetic kidney disease is the leading cause of end-stage renal disease. Podocytes are differentiated cells necessary for the development and maintenance of the glomerular basement membrane and the capillary tufts, as well as the function of the glomerular filtration barrier. The epithelial glomerular cells express a local renin-angiotensin system (RAS) that varies in different pathological situations such as hyperglycemia or mechanical stress. RAS components have been shown to be altered in diabetic podocytopathy, and their modulation may modify diabetic nephropathy progression. Podocytes are a direct target for angiotensin II-mediated injury by altered expression and distribution of podocyte proteins. Furthermore, angiotensin II promotes podocyte injury indirectly by inducing cellular hypertrophy, increased apoptosis, and changes in the anionic charge of the glomerular basement membrane, among other effects. RAS blockade has been shown to decrease the level of proteinuria and delay the progression of chronic kidney disease. This review summarizes the local intraglomerular RAS and its imbalance in diabetic podocytopathy. A better understanding of the intrapodocyte RAS might provide a new approach for diabetic kidney disease treatment.
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Affiliation(s)
- Eva Márquez
- Department of Nephrology, Hospital del Mar, Barcelona, Spain; IMIM (Hospital del Mar Medical Research Institute), Barcelona, Spain; and
| | - Marta Riera
- Department of Nephrology, Hospital del Mar, Barcelona, Spain; IMIM (Hospital del Mar Medical Research Institute), Barcelona, Spain; and Red de Investigación Renal (REDINREN), Instituto Carlos III, Madrid, Spain
| | - Julio Pascual
- Department of Nephrology, Hospital del Mar, Barcelona, Spain; IMIM (Hospital del Mar Medical Research Institute), Barcelona, Spain; and Red de Investigación Renal (REDINREN), Instituto Carlos III, Madrid, Spain
| | - María José Soler
- Department of Nephrology, Hospital del Mar, Barcelona, Spain; IMIM (Hospital del Mar Medical Research Institute), Barcelona, Spain; and Red de Investigación Renal (REDINREN), Instituto Carlos III, Madrid, Spain
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112
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Rafiq K, Nishiyama A, Konishi Y, Morikawa T, Kitabayashi C, Kohno M, Masaki T, Mori H, Kobori H, Imanishi M. Regression of glomerular and tubulointerstitial injuries by dietary salt reduction with combination therapy of angiotensin II receptor blocker and calcium channel blocker in Dahl salt-sensitive rats. PLoS One 2014; 9:e107853. [PMID: 25233358 PMCID: PMC4169441 DOI: 10.1371/journal.pone.0107853] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2014] [Accepted: 08/15/2014] [Indexed: 12/24/2022] Open
Abstract
A growing body of evidence indicates that renal tissue injuries are reversible. We investigated whether dietary salt reduction with the combination therapy of angiotensin II type 1 receptor blocker (ARB) plus calcium channel blocker (CCB) reverses renal tissue injury in Dahl salt-sensitive (DSS) hypertensive rats. DSS rats were fed a high-salt diet (HS; 4% NaCl) for 4 weeks. Then, DSS rats were given one of the following for 10 weeks: HS diet; normal-salt diet (NS; 0.5% NaCl), NS + an ARB (olmesartan, 10 mg/kg/day), NS + a CCB (azelnidipine, 3 mg/kg/day), NS + olmesartan + azelnidipine or NS + hydralazine (50 mg/kg/day). Four weeks of treatment with HS diet induced hypertension, proteinuria, glomerular sclerosis and hypertrophy, glomerular podocyte injury, and tubulointerstitial fibrosis in DSS rats. A continued HS diet progressed hypertension, proteinuria and renal tissue injury, which was associated with inflammatory cell infiltration and increased proinflammatory cytokine mRNA levels, NADPH oxidase activity and NADPH oxidase-dependent superoxide production in the kidney. In contrast, switching to NS halted the progression of hypertension, renal glomerular and tubular injuries. Dietary salt reduction with ARB or with CCB treatment further reduced blood pressure and partially reversed renal tissues injury. Furthermore, dietary salt reduction with the combination of ARB plus CCB elicited a strong recovery from HS-induced renal tissue injury including the attenuation of inflammation and oxidative stress. These data support the hypothesis that dietary salt reduction with combination therapy of an ARB plus CCB restores glomerular and tubulointerstitial injury in DSS rats.
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Affiliation(s)
- Kazi Rafiq
- Department of Pharmacology, Faculty of Medicine, Kagawa University, Kagawa, Japan
- * E-mail:
| | - Akira Nishiyama
- Department of Pharmacology, Faculty of Medicine, Kagawa University, Kagawa, Japan
| | - Yoshio Konishi
- Division of Nephrology and Hypertension, Osaka City General Hospital, Osaka, Japan
| | - Takashi Morikawa
- Division of Nephrology and Hypertension, Osaka City General Hospital, Osaka, Japan
| | - Chizuko Kitabayashi
- Division of Nephrology and Hypertension, Osaka City General Hospital, Osaka, Japan
| | - Masakazu Kohno
- Department of Cardiorenal and Cerebrovascular Medicine, Faculty of Medicine, Kagawa University, Kagawa, Japan
| | - Tsutomu Masaki
- Department of Gastroenterology, Faculty of Medicine, Kagawa University, Kagawa, Japan
| | - Hirohito Mori
- Department of Gastroenterology, Faculty of Medicine, Kagawa University, Kagawa, Japan
| | - Hiroyuki Kobori
- Department of Pharmacology, Faculty of Medicine, Kagawa University, Kagawa, Japan
| | - Masahito Imanishi
- Division of Nephrology and Hypertension, Osaka City General Hospital, Osaka, Japan
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113
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Jefferson JA, Shankland SJ. The pathogenesis of focal segmental glomerulosclerosis. Adv Chronic Kidney Dis 2014; 21:408-16. [PMID: 25168829 DOI: 10.1053/j.ackd.2014.05.009] [Citation(s) in RCA: 76] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2014] [Accepted: 05/30/2014] [Indexed: 01/13/2023]
Abstract
Focal segmental glomerulosclerosis (FSGS) is a histologic pattern of injury on kidney biopsy that can arise from a diverse range of causes and mechanisms. Although primary and secondary forms are described based on the underlying cause, there are many common factors that underlie the development of this segmental injury. In this review, we will describe the currently accepted model for the pathogenesis of classic FSGS and review the data supporting this model. Although the podocyte is considered the major target of injury in FSGS, we will also highlight the contributions of other resident glomerular cells in the development of FSGS.
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Zhang J, Yanez D, Floege A, Lichtnekert J, Krofft RD, Liu ZH, Pippin JW, Shankland SJ. ACE-inhibition increases podocyte number in experimental glomerular disease independent of proliferation. J Renin Angiotensin Aldosterone Syst 2014; 16:234-48. [PMID: 25143333 PMCID: PMC4412792 DOI: 10.1177/1470320314543910] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
Objective The objective of this article is to test the effects of angiotensin-converting enzyme (ACE)-inhibition on glomerular epithelial cell number in an inducible experimental model of focal segmental glomerulosclerosis (FSGS). Background Although ACE-inhibition has been shown to limit podocyte loss by enhancing survival, little is known about its effect on podocyte number following an abrupt decline in disease. Methods Experimental FSGS was induced with cytotoxic antipodocyte antibody. Following induction, groups were randomized to receive the ACE-inhibitor enalapril, the smooth muscle relaxant hydralazine (blood pressure control) or drinking water. Blood pressure, kidney function and histology were measured seven and 14 days following disease induction. Results Both glomerulosclerosis and urinary albumin-to-creatinine ratio were less in the ACE-inhibition arm at day 14. At day 7 of disease, mean podocyte numbers were 26% and 29% lower in the enalapril and hydralazine arms, respectively, compared to normal mice in which no antibody was injected. At day 14, the mean podocyte number was only 18% lower in the enalapril arm, but was 39% lower in the hydralazine arm compared to normal mice. Podocyte proliferation did not occur at any time in any group. Compared to water- or hydralazine-treated mice with FSGS, the enalapril arm had a higher mean number of glomerular parietal epithelial cells that co-expressed the podocyte proteins WT-1 and synaptopodin, as well as phospho-ERK. Conclusion The results show following an abrupt decline in podocyte number, the initiation of ACE-inhibition but not hydralazine, was accompanied by higher podocyte number in the absence of proliferation. This was accompanied by a higher number of parietal epithelial cells that co-express podocyte proteins. Increasing podocyte number appears to be accompanied by reduced glomerulosclerosis.
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Affiliation(s)
- Jiong Zhang
- Division of Nephrology, Department of Medicine, University of Washington School of Medicine, Washington Current address: Research Institute of Nephrology, Jinling Hospital, Nanjing University School of Medicine, China
| | - David Yanez
- Department of Biostatistics, School of Public Health, University of Washington, Washington
| | - Anna Floege
- Division of Nephrology, Department of Medicine, University of Washington School of Medicine, Washington
| | - Julia Lichtnekert
- Division of Nephrology, Department of Medicine, University of Washington School of Medicine, Washington
| | - Ronald D Krofft
- Division of Nephrology, Department of Medicine, University of Washington School of Medicine, Washington
| | - Zhi-Hong Liu
- Research Institute of Nephrology, Jinling Hospital, Nanjing University School of Medicine, China
| | - Jeffrey W Pippin
- Division of Nephrology, Department of Medicine, University of Washington School of Medicine, Washington
| | - Stuart J Shankland
- Division of Nephrology, Department of Medicine, University of Washington School of Medicine, Washington
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Effects of CP-900691, a novel peroxisome proliferator-activated receptor α, agonist on diabetic nephropathy in the BTBR ob/ob mouse. J Transl Med 2014; 94:851-62. [PMID: 24955894 PMCID: PMC4404155 DOI: 10.1038/labinvest.2014.80] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2013] [Revised: 05/02/2014] [Accepted: 05/20/2014] [Indexed: 12/14/2022] Open
Abstract
Piperidine-based peroxisome proliferator-activated receptor-α agonists are agents that are efficacious in improving lipid, glycemic, and inflammatory indicators in diabetes and obesity. This study sought to determine whether CP-900691 ((S)-3-[3-(1-carboxy-1-methyl-ethoxy)-phenyl]-piperidine-1-carboxylic acid 4-trifluoromethyl-benzyl ester; CP), a member of this novel class of agents, by decreasing plasma triglycerides, could prevent diabetic nephropathy in the Black and Tan, BRachyuric (BTBR) ob/ob mouse model of type 2 diabetes mellitus. Four-week old female BTBR WT and BTBR ob/ob mice received either regular chow or one containing CP (3 mg/kg per day) for 14 weeks. CP elevated plasma high-density lipoprotein, albuminuria, and urinary excretion of 8-epi PGF(2α), a product of the nonenzymatic metabolism of arachidonic acid and whose production is elevated in oxidative stress, in BTBR WT mice. In BTBR ob/ob mice, CP reduced plasma triglycerides and non-esterified fatty acids, fasting blood glucose, body weight, and plasma interleukin-6, while concomitantly improving insulin resistance. Despite these beneficial metabolic effects, CP had no effect on elevated plasma insulin, 8-epi PGF(2α) excretion, and albuminuria, and surprisingly, did not ameliorate the development of diabetic nephropathy, having no effect on the accumulation of renal macrophages, glomerular hypertrophy, and increased mesangial matrix expansion. In addition, CP did not increase plasma high-density lipoprotein in BTBR ob/ob mice, while paradoxically increasing total cholesterol levels. These findings indicate that 8-epi PGF(2α), possibly along with hyperinsulinemia and inflammatory and dysfunctional lipoproteins, is integral to the development of diabetic nephropathy and should be considered as a potential target of therapy in the treatment of diabetic nephropathy.
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116
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Betz B, Conway BR. Recent Advances in Animal Models of Diabetic Nephropathy. ACTA ACUST UNITED AC 2014; 126:191-5. [DOI: 10.1159/000363300] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2014] [Accepted: 04/29/2014] [Indexed: 11/19/2022]
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Gembardt F, Bartaun C, Jarzebska N, Mayoux E, Todorov VT, Hohenstein B, Hugo C. The SGLT2 inhibitor empagliflozin ameliorates early features of diabetic nephropathy in BTBR ob/ob type 2 diabetic mice with and without hypertension. Am J Physiol Renal Physiol 2014; 307:F317-25. [PMID: 24944269 DOI: 10.1152/ajprenal.00145.2014] [Citation(s) in RCA: 147] [Impact Index Per Article: 14.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Diabetic nephropathy is the leading cause of end-stage renal disease in humans in the Western world. The recent development of Na+-glucose cotransporter 2 (SGLT2) inhibitors offers a new antidiabetic therapy via enhanced glucose excretion. Whether this strategy exerts beneficial effects on the development of type 2 diabetic nephropathy is still largely unclear. We investigated the effects of the specific SGLT2 inhibitor empagliflozin in BTBR.Cg-Lep<ob>/WiscJ (BTBR ob/ob) mice, which spontaneously develop type 2 diabetic nephropathy. In the first experiment, BTBR ob/ob mice received either a diet containing 300 ppm empagliflozin or equicaloric placebo chow for 12 wk. In the second experiment, BTBR ob/ob mice received 1 μg·kg body wt(-1)·day(-1) ANG II to induce arterial hypertension and were separated into the same two diet groups for 6 wk. In both experiments, empagliflozin treatment enhanced glucosuria, thereby lowering blood glucose. Independently of hypertension, empagliflozin reduced albuminuria in diabetic mice. However, empagliflozin treatment affected diabetes-related glomerular hypertrophy, markers of renal inflammation, and mesangial matrix expansion only in BTBR ob/ob mice without hypertension. In summary, empagliflozin demonstrated significant antihyperglycemic effects, differentially ameliorating early features of diabetic nephropathy in BTBR ob/ob mice with and without hypertension.
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Affiliation(s)
- Florian Gembardt
- Division of Nephrology, Department of Internal Medicine III, University Hospital Carl Gustav Carus at the Technische Universität Dresden, Dresden, Germany; and
| | - Christoph Bartaun
- Division of Nephrology, Department of Internal Medicine III, University Hospital Carl Gustav Carus at the Technische Universität Dresden, Dresden, Germany; and
| | - Natalia Jarzebska
- Division of Nephrology, Department of Internal Medicine III, University Hospital Carl Gustav Carus at the Technische Universität Dresden, Dresden, Germany; and
| | - Eric Mayoux
- Divison of Research, Boehringer Ingelheim Pharma, Biberach/Riss, Germany
| | - Vladimir T Todorov
- Division of Nephrology, Department of Internal Medicine III, University Hospital Carl Gustav Carus at the Technische Universität Dresden, Dresden, Germany; and
| | - Bernd Hohenstein
- Division of Nephrology, Department of Internal Medicine III, University Hospital Carl Gustav Carus at the Technische Universität Dresden, Dresden, Germany; and
| | - Christian Hugo
- Division of Nephrology, Department of Internal Medicine III, University Hospital Carl Gustav Carus at the Technische Universität Dresden, Dresden, Germany; and
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Abstract
The very limited ability of adult podocytes to proliferate in vivo is clinically significant because podocytes form a vascular barrier that is functionally critical to the nephron, podocyte hypoplasia is a characteristic of disease, and inadequate regeneration of podocytes is a major cause of persistent podocyte hypoplasia. Excessive podocyte loss or inadequate replacement leads to glomerulosclerosis in many progressive kidney diseases. Thus, restoration of podocyte cell density almost certainly is reliant on regeneration by podocyte progenitors. However, such putative progenitors have remained elusive until recently. In this review, we describe the developmental processes leading to podocyte and parietal epithelial cell (PEC) formation during glomerulogenesis. We compare evidence that in normal human kidneys PECs expressing progenitor markers CD133 and CD24 can differentiate into podocytes in vitro and in vivo, with evidence from animal models suggesting a more limited role of the PEC's capacity to serve as a podocyte progenitor in adults. We highlight tantalizing new evidence that specialized vascular wall cells of afferent arterioles, including those that produce renin in healthy kidney, provide a novel local progenitor source of new PECs and podocytes in response to podocyte hypoplasia in the adult, and draw comparisons with glomerulogenesis.
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Affiliation(s)
- Stuart J Shankland
- Division of Nephrology, Department of Medicine, University of Washington School of Medicine, Seattle, WA.
| | - Jeffrey W Pippin
- Division of Nephrology, Department of Medicine, University of Washington School of Medicine, Seattle, WA
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Report on ISN Forefronts, Florence, Italy, 12-15 September 2013: Stem cells and kidney regeneration. Kidney Int 2014; 86:23-7. [PMID: 24897031 DOI: 10.1038/ki.2014.32] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2013] [Revised: 01/02/2014] [Accepted: 01/09/2014] [Indexed: 02/07/2023]
Abstract
In recent years it has become clear that most organs and tissues, including kidney, contain resident stem/progenitor cells. Stem cells are undifferentiated, long-lived cells that are unique in their ability to produce differentiated daughter cells and to retain their stem cell identity by self-renewal. A primary goal of this meeting was to review the current understanding of kidney stem cells and mechanisms of kidney regeneration in both lower vertebrates and mammals. Presenters covered a broad range of topics including stem cell quiescence, epigenetics, transcriptional control circuits, dedifferentiation, pluripotent stem cells, renal progenitors, and novel imaging approaches in kidney regeneration. By the end of this highly interactive conference it was clear we are entering into very exciting times for regenerative medicine and the kidney.
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Abstract
BACKGROUND Several organs such as the skin and liver have a great capacity for regeneration. However, many approaches only delay the progression of end-stage kidney disease and do not achieve efficient long-term stabilization, let alone regeneration. SUMMARY In mammals, the kidney has an innate but limited capacity for regeneration which can only modify the nephron structure and function but not increase the nephron number. Several clinical and animal studies have indicated that functional improvements and/or structural regression can occur in chronic kidney disease. Cell reconstitution, matrix remodeling, and tissue reorganization are major mechanisms for kidney regeneration. Current approaches achieve only partial kidney regeneration, but this does not occur in all animals and is not sustained in the long term. Multipronged and early interventions are future choices for the induction of kidney regeneration. KEY MESSAGES Kidney regeneration in mammals is feasible but limited and may be enhanced by multitargeting key mechanisms.
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Affiliation(s)
- Hai-Chun Yang
- Department of Pathology, Microbiology and Immunology, Vanderbilt University Medical Center, Nashville, Tenn., USA
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121
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Anders HJ. Immune system modulation of kidney regeneration--mechanisms and implications. Nat Rev Nephrol 2014; 10:347-58. [PMID: 24776845 DOI: 10.1038/nrneph.2014.68] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
The immune system is an important guardian of tissue homeostasis. In response to injury, resident and infiltrating immune cells orchestrate all phases of danger control, resolution of inflammation and tissue regeneration or scar formation. As mammalian postnatal kidneys are not capable of de novo nephrogenesis, recovery is limited to the regeneration or repair of existing nephrons. The regenerative capacity of the nephron varies between compartments; the epithelial cells of the tubule regenerate more efficiently than the structurally highly organized podocytes. Cells of the surrounding environment modulate nephron regeneration by secreting paracrine mediators. This Review discusses immune mediators and pathways that regulate the intrinsic regenerative capacity of the nephron. Eliminating injurious triggers, modulating renal inflammation and specifically enhancing the regenerative capacity of nephrons might be a promising strategy to improve long-term outcomes in patients with acute kidney injury and/or chronic kidney disease.
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Affiliation(s)
- Hans-Joachim Anders
- Nephrologisches Zentrum, Medizinische Klinik und Poliklinik IV, Klinikum der Universität München-Innenstadt, Ziemssenstrasse 1, 80336 Munich, Germany
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122
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Pippin JW, Glenn ST, Krofft RD, Rusiniak ME, Alpers CE, Hudkins K, Duffield JS, Gross KW, Shankland SJ. Cells of renin lineage take on a podocyte phenotype in aging nephropathy. Am J Physiol Renal Physiol 2014; 306:F1198-209. [PMID: 24647714 DOI: 10.1152/ajprenal.00699.2013] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
Aging nephropathy is characterized by podocyte depletion accompanied by progressive glomerulosclerosis. Replacement of terminally differentiated podocytes by local stem/progenitor cells is likely a critical mechanism for their regeneration. Recent studies have shown that cells of renin lineage (CoRL), normally restricted to the kidney's extraglomerular compartment, might serve this role after an abrupt depletion in podocyte number. To determine the effects of aging on the CoRL reserve and if CoRL moved from an extra- to the intraglomerular compartment during aging, genetic cell fate mapping was performed in aging Ren1cCre × Rs-ZsGreen reporter mice. Podocyte number decreased and glomerular scarring increased with advanced age. CoRL number decreased in the juxtaglomerular compartment with age. There was a paradoxical increase in CoRL in the intraglomerular compartment at 52 and 64 wk of age, where a subset coexpressed the podocyte proteins nephrin, podocin, and synaptopodin. Transmission electron microscopy studies showed that a subset of labeled CoRL in the glomerulus displayed foot processes, which attached to the glomerular basement membrane. No CoRL in the glomerular compartment stained for renin. These results suggest that, despite a decrease in the reserve, a subpopulation of CoRL moves to the glomerulus after chronic podocyte depletion in aging nephropathy, where they acquire a podocyte-like phenotype. This suggests that they might serve as adult podocyte stem/progenitor cells under these conditions, albeit in insufficient numbers to fully replace podocytes depleted with age.
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Affiliation(s)
- Jeffrey W Pippin
- Division of Nephrology, University of Washington, Seattle, Washington
| | - Sean T Glenn
- Department of Molecular and Cellular Biology, Roswell Park Cancer Institute, Buffalo, New York; and
| | - Ronald D Krofft
- Division of Nephrology, University of Washington, Seattle, Washington
| | - Michael E Rusiniak
- Department of Molecular and Cellular Biology, Roswell Park Cancer Institute, Buffalo, New York; and
| | - Charles E Alpers
- Department of Pathology, University of Washington, Seattle, Washington
| | - Kelly Hudkins
- Department of Pathology, University of Washington, Seattle, Washington
| | - Jeremy S Duffield
- Division of Nephrology, University of Washington, Seattle, Washington
| | - Kenneth W Gross
- Department of Molecular and Cellular Biology, Roswell Park Cancer Institute, Buffalo, New York; and
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Mallipattu SK, Gallagher EJ, LeRoith D, Liu R, Mehrotra A, Horne SJ, Chuang PY, Yang VW, He JC. Diabetic nephropathy in a nonobese mouse model of type 2 diabetes mellitus. Am J Physiol Renal Physiol 2014; 306:F1008-17. [PMID: 24598803 DOI: 10.1152/ajprenal.00597.2013] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
A large body of research has contributed to our understanding of the pathophysiology of diabetic nephropathy. Yet, many questions remain regarding the progression of a disease that accounts for nearly half the patients entering dialysis yearly. Several murine models of diabetic nephropathy secondary to Type 2 diabetes mellitus (T2DM) do exist, and some are more representative than others, but all have limitations. In this study, we aimed to identify a new mouse model of diabetic nephropathy secondary to T2DM in a previously described T2DM model, the MKR (MCK-KR-hIGF-IR) mouse. In this mouse model, T2DM develops as a result of functional inactivation of insulin-like growth factor-1 receptor (IGF-1R) in the skeletal muscle. These mice are lean, with marked insulin resistance, hyperinsulinemia, hyperglycemia, and dyslipidemia and thus are representative of nonobese human T2DM. We show that the MKR mice, when under stress (high-fat diet or unilateral nephrectomy), develop progressive diabetic nephropathy with marked albuminuria and meet the histopathological criteria as defined by the Animal Models of Diabetic Complications Consortium. Finally, these MKR mice are fertile and are on a common background strain, making it a novel model to study the progression of diabetic nephropathy.
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Affiliation(s)
- Sandeep K Mallipattu
- Dept. of Medicine/Nephrology, Mount Sinai School of Medicine, One Gustave L Levy Place, Box 1243, New York, NY.
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Lin CL, Lee PH, Hsu YC, Lei CC, Ko JY, Chuang PC, Huang YT, Wang SY, Wu SL, Chen YS, Chiang WC, Reiser J, Wang FS. MicroRNA-29a promotion of nephrin acetylation ameliorates hyperglycemia-induced podocyte dysfunction. J Am Soc Nephrol 2014; 25:1698-709. [PMID: 24578127 DOI: 10.1681/asn.2013050527] [Citation(s) in RCA: 145] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022] Open
Abstract
Podocyte dysfunction is a detrimental feature in diabetic nephropathy, with loss of nephrin integrity contributing to diabetic podocytopathy. MicroRNAs (miRs) reportedly modulate the hyperglycemia-induced perturbation of renal tissue homeostasis. This study investigated whether regulation of histone deacetylase (HDAC) actions and nephrin acetylation by miR-29 contributes to podocyte homeostasis and renal function in diabetic kidneys. Hyperglycemia accelerated podocyte injury and reduced nephrin, acetylated nephrin, and miR-29a levels in primary renal glomeruli from streptozotocin-induced diabetic mice. Diabetic miR-29a transgenic mice had better nephrin levels, podocyte viability, and renal function and less glomerular fibrosis and inflammation reaction compared with diabetic wild-type mice. Overexpression of miR-29a attenuated the promotion of HDAC4 signaling, nephrin ubiquitination, and urinary nephrin excretion associated with diabetes and restored nephrin acetylation. Knockdown of miR-29a by antisense oligonucleotides promoted HDAC4 action, nephrin loss, podocyte apoptosis, and proteinuria in nondiabetic mice. In vitro, interruption of HDAC4 signaling alleviated the high glucose-induced apoptosis and inhibition of nephrin acetylation in podocyte cultures. Furthermore, HDAC4 interference increased the acetylation status of histone H3 at lysine 9 (H3K9Ac), the enrichment of H3K9Ac in miR-29a proximal promoter, and miR-29a transcription in high glucose-stressed podocytes. In conclusion, hyperglycemia impairs miR-29a signaling to intensify HDAC4 actions that contribute to podocyte protein deacetylation and degradation as well as renal dysfunction. HDAC4, via epigenetic H3K9 hypoacetylation, reduces miR-29a transcription. The renoprotective effects of miR-29a in diabetes-induced loss of podocyte integrity and renal homeostasis highlights the importance of post-translational acetylation reactions in podocyte microenvironments. Increasing miR-29a action may protect against diabetic podocytopathy.
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Affiliation(s)
- Chun-Liang Lin
- Department of Nephrology and Kidney and Diabetic Complications Research Team, Chang Gung Memorial Hospital, Chiayi, Taiwan; Kidney Research Center, Chang Gung Memorial Hospital, Taipei, Taiwan; School of Traditional Chinese Medicine and
| | - Pei-Hsien Lee
- Department of Nephrology and Kidney and Diabetic Complications Research Team, Chang Gung Memorial Hospital, Chiayi, Taiwan
| | - Yung-Chien Hsu
- Department of Nephrology and Kidney and Diabetic Complications Research Team, Chang Gung Memorial Hospital, Chiayi, Taiwan
| | - Chen-Chou Lei
- Department of Nephrology and Kidney and Diabetic Complications Research Team, Chang Gung Memorial Hospital, Chiayi, Taiwan
| | - Jih-Yang Ko
- Departments of Orthopedic Surgery and Center for Translational Research in Biomedical Sciences, Kaohsiung Chang Gung Memorial Hospital, Kaohsiung, Taiwan
| | | | | | | | | | | | - Wen-Chih Chiang
- Department of Internal Medicine, National Taiwan University Hospital, Taipei, Taiwan
| | - Jochen Reiser
- Department of Medicine, Rush University Medical Center, Chicago, Illinois; and
| | - Feng-Sheng Wang
- Center for Translational Research in Biomedical Sciences, Kaohsiung Chang Gung Memorial Hospital, Kaohsiung, Taiwan; Medical Research and Graduate Institute of Clinical Medical Science, Chang Gung University College of Medicine, TaoYuan, Taiwan
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126
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Wang L, Tang Y, Eisner W, Sparks MA, Buckley AF, Spurney RF. Augmenting podocyte injury promotes advanced diabetic kidney disease in Akita mice. Biochem Biophys Res Commun 2014; 444:622-7. [PMID: 24491571 DOI: 10.1016/j.bbrc.2014.01.115] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2014] [Accepted: 01/23/2014] [Indexed: 01/13/2023]
Abstract
To determine if augmenting podocyte injury promotes the development of advanced diabetic nephropathy (DN), we created mice that expressed the enzyme cytosine deaminase (CD) specifically in podocytes of diabetic Akita mice (Akita-CD mice). In these mice, treatment with the prodrug 5-flucytosine (5-FC) causes podocyte injury as a result of conversion to the toxic metabolite 5-fluorouracil (5-FU). We found that treatment of 4-5 week old Akita mice with 5-FC for 5 days caused robust albuminuria at 16 and 20 weeks of age compared to 5-FC treated Akita controls, which do not express CD (Akita CTLs). By 20 weeks of age, there was a significant increase in mesangial expansion in Akita-CD mice compared to Akita CTLs, which was associated with a variable increase in glomerular basement membrane (GBM) width and interstitial fibrosis. At 20 weeks of age, podocyte number was similarly reduced in both groups of Akita mice, and was inversely correlated with the albuminuria and mesangial expansion. Thus, enhancing podocyte injury early in the disease process promotes the development of prominent mesangial expansion, interstitial fibrosis, increased GBM thickness and robust albuminuria. These data suggest that podocytes play a key role in the development of advanced features of diabetic kidney disease.
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Affiliation(s)
- Liming Wang
- Division of Nephrology, Department of Medicine, Duke University and Durham VA Medical Centers, Durham, NC 27710, United States
| | - Yuping Tang
- Division of Nephrology, Department of Medicine, Duke University and Durham VA Medical Centers, Durham, NC 27710, United States
| | - William Eisner
- Division of Nephrology, Department of Medicine, Duke University and Durham VA Medical Centers, Durham, NC 27710, United States
| | - Matthew A Sparks
- Division of Nephrology, Department of Medicine, Duke University and Durham VA Medical Centers, Durham, NC 27710, United States
| | - Anne F Buckley
- Department of Pathology, Duke University Medical Center, Durham, NC 27710, United States
| | - Robert F Spurney
- Division of Nephrology, Department of Medicine, Duke University and Durham VA Medical Centers, Durham, NC 27710, United States.
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Shankland SJ, Smeets B, Pippin JW, Moeller MJ. The emergence of the glomerular parietal epithelial cell. Nat Rev Nephrol 2014; 10:158-73. [PMID: 24468766 DOI: 10.1038/nrneph.2014.1] [Citation(s) in RCA: 112] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Glomerular diseases are the leading causes of chronic and end-stage kidney disease. In the 1980s and 1990s, attention was focused on the biology and role of glomerular endothelial and mesangial cells. For the past two decades, seminal discoveries have been made in podocyte biology in health and disease. More recently, the glomerular parietal epithelial cell (PEC)-the fourth resident glomerular cell type-has been under active study, leading to a better understanding and definition of how these cells behave normally, and their potential roles in glomerular disease. Accordingly, this Review will focus on our current knowledge of PECs, in both health and disease. We discuss model systems to study PECs, how PECs might contribute to glomerulosclerosis, crescent and pseudocrescent formation and how PECs handle filtered albumin. These events have consequences on PEC structure and function, and PECs have potential roles as stem or progenitor cells for podocytes in glomerular regeneration, which will also be described.
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Affiliation(s)
- Stuart J Shankland
- Division of Nephrology, University of Washington, 1959 North East Pacific Avenue, Box 356521, Room BB1269, Seattle, WA 98195-6521, USA
| | - Bart Smeets
- Nephrology and Clinical Immunology, University Hospital of the RWTH Aachen University, Pauwelsstraße 30, 52074 Aachen, Germany
| | - Jeffrey W Pippin
- Division of Nephrology, University of Washington, 1959 North East Pacific Avenue, Box 356521, Room BB1269, Seattle, WA 98195-6521, USA
| | - Marcus J Moeller
- Nephrology and Clinical Immunology, University Hospital of the RWTH Aachen University, Pauwelsstraße 30, 52074 Aachen, Germany
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128
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Berger K, Schulte K, Boor P, Kuppe C, van Kuppevelt TH, Floege J, Smeets B, Moeller MJ. The regenerative potential of parietal epithelial cells in adult mice. J Am Soc Nephrol 2014; 25:693-705. [PMID: 24408873 DOI: 10.1681/asn.2013050481] [Citation(s) in RCA: 88] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
Previously, we showed that some podocytes in juvenile mice are recruited from cells lining Bowman's capsule, suggesting that parietal epithelial cells (PECs) are a progenitor cell population for podocytes. To investigate whether PECs also replenish podocytes in adult mice, PECs were genetically labeled in an irreversible fashion in 5-week-old mice. No significant increase in labeled podocytes was observed, even after 18 months. To accelerate a potential regenerative mechanism, progressive glomerular hypertrophy was induced by progressive partial nephrectomies. Again, no significant podocyte replenishment was observed. Rather, labeled PECs exclusively invaded segments of the tuft affected by glomerulosclerosis, consistent with our previous findings. We next reassessed PEC recruitment in juvenile mice using a different reporter mouse and confirmed significant recruitment of labeled PECs onto the glomerular tuft. Moreover, some labeled cells on Bowman's capsule expressed podocyte markers, and cells on Bowman's capsule were also directly labeled in juvenile podocyte-specific Pod-rtTA transgenic mice. In 6-week-old mice, however, cells on Bowman's capsule no longer expressed podocyte-specific markers. Similarly, in human kidneys, some cells on Bowman's capsule expressed the podocyte marker synaptopodin from 2 weeks to 2 years of age but not at 7 years of age. In summary, podocyte regeneration from PECs could not be detected in aging mice or models of glomerular hypertrophy. We propose that a small fraction of committed podocytes reside on Bowman's capsule close to the vascular stalk and are recruited onto the glomerular tuft during infancy to adolescence in mice and humans.
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129
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Zhiqing W, Jing W, Haili X, Shaozhuang L, Chunxiao H, Haifeng H, Hui W, Sanyuan H. Renal function is ameliorated in a diabetic nephropathy rat model through a duodenal-jejunal bypass. Diabetes Res Clin Pract 2014; 103:26-34. [PMID: 24398318 DOI: 10.1016/j.diabres.2013.12.001] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/18/2013] [Accepted: 11/29/2013] [Indexed: 11/25/2022]
Abstract
AIMS Diabetes surgery is growing in popularity and has been shown to have marked effects on diabetes. However, several studies have shown it may induce some renal injury, and, currently, the impact of diabetes surgery on renal function is unclear. In this study, we examined renal function and histological changes in rats with diabetic nephropathy (DN) following a duodeno-jejunal bypass (DJB) operation. METHODS Rats with streptozotocin (STZ)-induced diabetes were randomly assigned to 3 groups: DJB group (DJB), Sham-DJB group (S-DJB) and diabetes group (DM). Six age-matched normal rats were assigned as the control group. DJB and sham surgery were performed. Body weight, food intake, glucose levels, lipid parameters, cystatin C (Cys_C) levels, serum and urinary creatinine, 24h urine albumin excretion rate (UAER) and glomerular filtration rate (GFR) were measured. Histological analysis and immunohistochemical studies of renal sections were also performed. RESULTS DJB ameliorated renal function by improving UAER, GFR and Cys_C levels 4 and 8 weeks after surgery. It also improved lipid metabolism by decreasing fasting total serum cholesterol (TC) and triglyceride (TG) levels. Immuno-staining of synaptopodin showed podocyte injury was also improved in DJB glomeruli compared with sham and DM groups. Histological analysis showed that the mesangial expansion was not significantly prevented 8 weeks after DJB surgery. CONCLUSION DJB ameliorated renal function in UAER and GFR but not mesangial expansion in a DN rat model. The improvement of renal function may be attributed to reversing the injury or loss of podocytes after DJB surgery.
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Affiliation(s)
- Wang Zhiqing
- Department of General Surgery, Qilu Hospital of Shandong University, Shandong, China; Department of General Surgery, The Fourth Hospital of Jinan, Shandong, China
| | - Wang Jing
- Department of Pathology, The Fourth Hospital of Jinan, Shandong, China
| | - Xu Haili
- Department of Internal Medicine, Jinan Municipal Hospital of Traditional Chinese Medicine, Shandong, China
| | - Liu Shaozhuang
- Department of General Surgery, Qilu Hospital of Shandong University, Shandong, China
| | - Hu Chunxiao
- Department of General Surgery, Qilu Hospital of Shandong University, Shandong, China
| | - Han Haifeng
- Department of General Surgery, Qilu Hospital of Shandong University, Shandong, China
| | - Wang Hui
- Department of General Surgery, The Fourth Hospital of Jinan, Shandong, China
| | - Hu Sanyuan
- Department of General Surgery, Qilu Hospital of Shandong University, Shandong, China.
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130
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Lim BJ, Yang HC, Fogo AB. Animal models of regression/progression of kidney disease. ACTA ACUST UNITED AC 2014; 11:45-51. [PMID: 25722733 DOI: 10.1016/j.ddmod.2014.06.003] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Current medical therapies may delay chronic kidney disease progression. However, increasing experimental evidence indicates remission or even regression can be achieved. In order to study mechanisms progression vs. regression by different interventions, appropriate animal models and research design must be implemented. We review key information of selected models, including etiology, pathogenesis, procedure, time course and assessment of potential regression.
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Affiliation(s)
- Beom Jin Lim
- Dept. of Pathology, Microbiology and Immunology, Vanderbilt University Medical Center, Nashville, TN, United States ; Dept. of Pathology, Yonsei University College of Medicine, Seoul, Korea
| | - Hai-Chun Yang
- Dept. of Pathology, Microbiology and Immunology, Vanderbilt University Medical Center, Nashville, TN, United States
| | - Agnes B Fogo
- Dept. of Pathology, Microbiology and Immunology, Vanderbilt University Medical Center, Nashville, TN, United States
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131
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Powell DW, Kenagy DN, Zheng S, Coventry SC, Xu J, Cai L, Carlson EC, Epstein PN. Associations between structural and functional changes to the kidney in diabetic humans and mice. Life Sci 2013; 93:257-64. [PMID: 23800643 PMCID: PMC3770478 DOI: 10.1016/j.lfs.2013.06.016] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2013] [Revised: 06/09/2013] [Accepted: 06/12/2013] [Indexed: 02/06/2023]
Abstract
Type 1 and Type 2 diabetic patients are at high risk of developing diabetic nephropathy (DN). Renal functional decline is gradual and there is high variability between patients, though the reason for the variability is unknown. Enough diabetic patients progress to end stage renal disease to make diabetes the leading cause of renal failure. The first symptoms of DN do not appear for years or decades after the onset of diabetes. During and after the asymptomatic period structural changes develop in the diabetic kidney. Typically, but not always, the first symptom of DN is albuminuria. Loss of renal filtration rate develops later. This review examines the structural abnormalities of diabetic kidneys that are associated with and possibly the basis for advancing albuminuria and declining GFR. Mouse models of diabetes and genetic manipulations of these models have become central to research into mechanisms underlying DN. This article also looks at the value of these mouse models to understanding human DN as well as potential pitfalls in translating the mouse results to humans.
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Affiliation(s)
- David W. Powell
- Department of Medicine, University of Louisville, Louisville, KY
| | - David N. Kenagy
- Department of Pedatrics, University of Louisville, Louisville, KY
| | - Shirong Zheng
- Department of Pedatrics, University of Louisville, Louisville, KY
| | | | - Jianxiang Xu
- Department of Pedatrics, University of Louisville, Louisville, KY
| | - Lu Cai
- Department of Pedatrics, University of Louisville, Louisville, KY
| | - Edward C. Carlson
- Department of Anatomy and Cell Biology, University of North Dakota, Grand Forks, ND
| | - Paul N. Epstein
- Department of Pedatrics, University of Louisville, Louisville, KY
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132
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Reversibility of diabetic nephropathy in a mouse model. Nat Rev Nephrol 2013. [DOI: 10.1038/nrneph.2013.88] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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133
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Nakagawa T, Sato W, Kosugi T, Johnson RJ. Uncoupling of VEGF with endothelial NO as a potential mechanism for abnormal angiogenesis in the diabetic nephropathy. J Diabetes Res 2013; 2013:184539. [PMID: 24386643 PMCID: PMC3872226 DOI: 10.1155/2013/184539] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/26/2013] [Accepted: 11/07/2013] [Indexed: 01/15/2023] Open
Abstract
Abnormal angiogenesis is a well characterized complication in diabetic retinopathy and is now recognized as a feature of diabetic nephropathy. The primary growth factor driving the increased angiogenesis in diabetic retinopathy and nephropathy is vascular endothelial growth factor (VEGF). While VEGF is considered an important growth factor for maintaining glomerular capillary integrity and function, increased action of VEGF in diabetic renal disease may carry adverse consequences. Studies by our group suggest that the effects of VEGF are amplified in the setting of endothelial dysfunction and low nitric oxide (NO) levels, which are a common feature in the diabetic state. The lack of NO may amplify the effects of VEGF to induce inflammation (via effects on the macrophage) and may lead to dysregulation of the vasculature, exacerbating features of diabetic renal disease. In this review, we summarize how an "uncoupling" of the VEGF-NO axis may contribute to the pathology of the diabetic kidney.
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Affiliation(s)
- Takahiko Nakagawa
- TMK Project, Kyoto University Graduate School of Medicine, Kyoto 606-8397, Japan
- *Takahiko Nakagawa:
| | - Waichi Sato
- Department of Nephrology, Nagoya University Graduate School of Medicine, 466-8550, Japan
| | - Tomoki Kosugi
- Department of Nephrology, Nagoya University Graduate School of Medicine, 466-8550, Japan
| | - Richard J. Johnson
- Division of Renal Diseases and Hypertension, University of Colorado Denver, Aurora, CO 80045, USA
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