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LeBleu VS, Kanasaki K, Lovisa S, Alge JL, Kim J, Chen Y, Teng Y, Gerami-Naini B, Sugimoto H, Kato N, Revuelta I, Grau N, Sleeman JP, Taduri G, Kizu A, Rafii S, Hochedlinger K, Quaggin SE, Kalluri R. Genetic reprogramming with stem cells regenerates glomerular epithelial podocytes in Alport syndrome. Life Sci Alliance 2024; 7:e202402664. [PMID: 38561223 PMCID: PMC10985218 DOI: 10.26508/lsa.202402664] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2024] [Revised: 03/13/2024] [Accepted: 03/14/2024] [Indexed: 04/04/2024] Open
Abstract
Glomerular filtration relies on the type IV collagen (ColIV) network of the glomerular basement membrane, namely, in the triple helical molecules containing the α3, α4, and α5 chains of ColIV. Loss of function mutations in the genes encoding these chains (Col4a3, Col4a4, and Col4a5) is associated with the loss of renal function observed in Alport syndrome (AS). Precise understanding of the cellular basis for the patho-mechanism remains unknown and a specific therapy for this disease does not currently exist. Here, we generated a novel allele for the conditional deletion of Col4a3 in different glomerular cell types in mice. We found that podocytes specifically generate α3 chains in the developing glomerular basement membrane, and that its absence is sufficient to impair glomerular filtration as seen in AS. Next, we show that horizontal gene transfer, enhanced by TGFβ1 and using allogenic bone marrow-derived mesenchymal stem cells and induced pluripotent stem cells, rescues Col4a3 expression and revive kidney function in Col4a3-deficient AS mice. Our proof-of-concept study supports that horizontal gene transfer such as cell fusion enables cell-based therapy in Alport syndrome.
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Affiliation(s)
- Valerie S LeBleu
- Department of Cancer Biology, University of Texas MD Anderson Cancer Center, Houston, TX, USA
- Division of Matrix Biology, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, MA, USA
- Northwestern University Feinberg School of Medicine and Kellogg School of Management, Chicago, IL, USA
- https://ror.org/02pttbw34 Department of Medicine, Baylor College of Medicine, Houston, TX, USA
| | - Keizo Kanasaki
- Division of Matrix Biology, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, MA, USA
| | - Sara Lovisa
- Department of Cancer Biology, University of Texas MD Anderson Cancer Center, Houston, TX, USA
| | - Joseph L Alge
- Department of Cancer Biology, University of Texas MD Anderson Cancer Center, Houston, TX, USA
- https://ror.org/02pttbw34 Department of Medicine, Baylor College of Medicine, Houston, TX, USA
| | - Jiha Kim
- Department of Cancer Biology, University of Texas MD Anderson Cancer Center, Houston, TX, USA
| | - Yang Chen
- Department of Cancer Biology, University of Texas MD Anderson Cancer Center, Houston, TX, USA
| | - Yingqi Teng
- Division of Matrix Biology, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, MA, USA
| | - Behzad Gerami-Naini
- Division of Matrix Biology, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, MA, USA
| | - Hikaru Sugimoto
- Department of Cancer Biology, University of Texas MD Anderson Cancer Center, Houston, TX, USA
- Division of Matrix Biology, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, MA, USA
| | - Noritoshi Kato
- Division of Matrix Biology, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, MA, USA
| | - Ignacio Revuelta
- Division of Matrix Biology, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, MA, USA
| | - Nicole Grau
- Medical Faculty Mannheim, University of Heidelberg, Heidelberg, Germany
- Department of Radiation Oncology, Heidelberg University Hospital, Heidelberg, Germany
| | - Jonathan P Sleeman
- Medical Faculty Mannheim, University of Heidelberg, Heidelberg, Germany
- Karlsruhe Institute of Technology (IBCS-BIP), Karlsruhe, Germany
| | - Gangadhar Taduri
- Division of Matrix Biology, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, MA, USA
| | - Akane Kizu
- Division of Matrix Biology, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, MA, USA
| | - Shahin Rafii
- Department of Genetic Medicine and Ansary Stem Cell Institute, Weill Cornell Medical College, New York, NY, USA
| | - Konrad Hochedlinger
- Massachusetts General Hospital, Boston, MA, USA
- Harvard Stem Cell Institute, Boston, MA, USA
| | - Susan E Quaggin
- Northwestern University Feinberg School of Medicine & Feinberg Cardiovascular and Renal Research Institute, Chicago, IL, USA
| | - Raghu Kalluri
- Department of Cancer Biology, University of Texas MD Anderson Cancer Center, Houston, TX, USA
- Division of Matrix Biology, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, MA, USA
- Harvard Stem Cell Institute, Boston, MA, USA
- Harvard-MIT Division of Health Sciences and Technology, Boston, MA, USA
- Department of Bioengineering, Rice University, Houston, TX, USA
- https://ror.org/02pttbw34 Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, TX, USA
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2
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Namba M, Kobayashi T, Kohno M, Koyano T, Hirose T, Fukushima M, Matsuyama M. Creation of X-linked Alport syndrome rat model with Col4a5 deficiency. Sci Rep 2021; 11:20836. [PMID: 34675305 PMCID: PMC8531394 DOI: 10.1038/s41598-021-00354-y] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2021] [Accepted: 10/12/2021] [Indexed: 12/31/2022] Open
Abstract
Alport syndrome is an inherited chronic human kidney disease, characterized by glomerular basement membrane abnormalities. This disease is caused by mutations in COL4A3, COL4A4, or COL4A5 gene. The knockout mice for Col4α3, Col4α4, and Col4α5 are developed and well characterized for the study of Alport syndrome. However, disease progression and effects of pharmacological therapy depend on the genetic variability. This model was reliable only to mouse. In this study, we created a novel Alport syndrome rat model utilizing the rGONAD technology, which generated rat with a deletion of the Col4α5 gene. Col4α5 deficient rats showed hematuria, proteinuria, high levels of BUN, Cre, and then died at 18 to 28 weeks of age (Hemizygous mutant males). Histological and ultrastructural analyses displayed the abnormalities including parietal cell hyperplasia, mesangial sclerosis, and interstitial fibrosis. Then, we demonstrated that α3/α4/α5 (IV) and α5/α5/α6 (IV) chains of type IV collagen disrupted in Col4α5 deficient rats. Thus, Col4α5 mutant rat is a reliable candidate for the Alport syndrome model for underlying the mechanism of kidney diseases and further identifying potential therapeutic targets for human renal diseases.
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Affiliation(s)
- Masumi Namba
- Division of Molecular Genetics, Shigei Medical Research Institute, 2117 Yamada, Minami-ku, Okayama, 701-0202, Japan
| | - Tomoe Kobayashi
- Division of Molecular Genetics, Shigei Medical Research Institute, 2117 Yamada, Minami-ku, Okayama, 701-0202, Japan
| | - Mayumi Kohno
- Division of Molecular Genetics, Shigei Medical Research Institute, 2117 Yamada, Minami-ku, Okayama, 701-0202, Japan
| | - Takayuki Koyano
- Division of Molecular Genetics, Shigei Medical Research Institute, 2117 Yamada, Minami-ku, Okayama, 701-0202, Japan
| | - Takuo Hirose
- Division of Nephrology and Endocrinology, Faculty of Medicine, Tohoku Medical and Pharmaceutical University, Sendai, Japan.,Department of Endocrinology and Applied Medicine, Tohoku University Graduate School of Medicine, Sendai, Japan
| | - Masaki Fukushima
- Division of Molecular Genetics, Shigei Medical Research Institute, 2117 Yamada, Minami-ku, Okayama, 701-0202, Japan.,Shigei Medical Research Hospital, Okayama, Japan
| | - Makoto Matsuyama
- Division of Molecular Genetics, Shigei Medical Research Institute, 2117 Yamada, Minami-ku, Okayama, 701-0202, Japan.
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3
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Torra R, Furlano M. New therapeutic options for Alport syndrome. Nephrol Dial Transplant 2020; 34:1272-1279. [PMID: 31190059 DOI: 10.1093/ndt/gfz131] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2019] [Accepted: 05/31/2019] [Indexed: 12/12/2022] Open
Abstract
Alport syndrome (AS) is the most frequent inherited kidney disease after autosomal dominant polycystic kidney disease. It has three different patterns of inheritance-autosomal dominant, autosomal recessive and X-linked-which in part explains the wide spectrum of disease, ranging from isolated microhaematuria to end-stage renal disease early in life. The search for a treatment for AS is being pursued vigorously, not only because of the obvious unmet need but also because AS is a rare disease and any drug approved will have an orphan drug designation with its various benefits. Moreover, AS patients are quite young with very few comorbidities, which facilitates clinical trials. This review identifies the particularities of each pattern of inheritance but focuses mainly on new drugs or therapeutic targets for the disease. Most treatment-related investigations are directed not at the main abnormality in AS, namely collagen IV composition, but rather at the associated inflammation and fibrosis. Thus, AS may serve as a proof of concept for numerous drugs of potential value in many diseases that cause chronic kidney disease.
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Affiliation(s)
- Roser Torra
- Inherited Renal Disorders, Nephrology Department, Fundació Puigvert, REDINREN, IIB Sant Pau, Universitat Autònoma de Barcelona, Barcelona, Spain
| | - Mónica Furlano
- Inherited Renal Disorders, Nephrology Department, Fundació Puigvert, REDINREN, IIB Sant Pau, Universitat Autònoma de Barcelona, Barcelona, Spain
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Nephroprotektive Therapie am Beispiel des Alport-Syndroms. Monatsschr Kinderheilkd 2019. [DOI: 10.1007/s00112-018-0641-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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5
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Gross O, Hoefele J. Genetische Ursachen und Therapie beim Alport-Syndrom. MED GENET-BERLIN 2019. [DOI: 10.1007/s11825-018-0214-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Zusammenfassung
Bei der Typ IV Kollagen-Erkrankung Alport-Syndrom (AS) handelt es sich um eine progressive hereditäre Nephropathie. Klinische Zeichen sind zunächst Hämaturie und Proteinurie, im weiteren Verlauf kommt es zu einem terminalen Nierenversagen. Zusätzlich werden extrarenale Manifestationen wie Innenohr-Schwerhörigkeit und Augenveränderungen beobachtet. Man unterscheidet drei Erbgänge: 85 % der Fälle sind X-chromosomal, ca. 10 % autosomal und weniger als 5 % digenisch. Ursächlich sind Varianten in den Kollagen Typ IV-Genen COL4A3, COL4A4 (beide autosomal) und COL4A5 (X-chromosomal). Die Symptomatik heterozygoter Anlageträger wurde früher als benigne familiäre Hämaturie bezeichnet. Da Anlageträger jedoch häufig keinen benignen Verlauf zeigen, werden sie inzwischen auch unter der Diagnose „Alport-Syndrom“ geführt.
Der Humangenetiker hat daher beim AS eine wichtige Lotsenfunktion: Bei früher Diagnose ist das AS inzwischen gut behandelbar, wodurch das terminale Nierenversagen um mehrere Jahre hinausgezögert und damit die Lebenserwartung verbessert werden kann. Aufgrund der Therapiemöglichkeiten sollte die (molekulargenetische) Diagnose bei Betroffenen, auch bei heterozygoten Anlageträgern, frühzeitig gestellt werden.
Mit diesem Artikel sollen die genetischen Ursachen des AS, mögliche genetische Einflussfaktoren auf den variablen Phänotyp, die unterschiedlichen Krankheitsstadien, Komplikationen sowie die derzeit zugelassene Behandlung aufgezeigt werden, um eine bestmögliche lebenslange Betreuung des Patienten zu gewährleisten.
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Affiliation(s)
- Oliver Gross
- Aff1 0000 0001 0482 5331 grid.411984.1 Klinik für Nephrologie und Rheumatologie Universitätsmedizin Göttingen Robert-Koch Str. 40 37075 Göttingen Deutschland
| | - Julia Hoefele
- Aff2 Institut für Humangenetik Klinikum rechts der Isar, Technische Universität München Trogerstr. 32 81675 München Deutschland
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COL4A6 is dispensable for autosomal recessive Alport syndrome. Sci Rep 2016; 6:29450. [PMID: 27377778 PMCID: PMC4932521 DOI: 10.1038/srep29450] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2016] [Accepted: 06/17/2016] [Indexed: 01/27/2023] Open
Abstract
Alport syndrome is caused by mutations in the genes encoding α3, α4, or α5 (IV) chains. Unlike X-linked Alport mice, α5 and α6 (IV) chains are detected in the glomerular basement membrane of autosomal recessive Alport mice, however, the significance of this finding remains to be investigated. We therefore generated mice lacking both α3 and α6 (IV) chains and compared their renal function and survival with Col4a3 knockout mice of 129 × 1/Sv background. No significant difference was observed in the renal function or survival of the two groups, or when the mice were backcrossed once to C57BL/6 background. However, the survival of backcrossed double knockout mice was significantly longer than that of the mice of 129 × 1/Sv background, which suggests that other modifier genes were involved in this phenomenon. In further studies we identified two Alport patients who had a homozygous mutation in intron 46 of COL4A4. The α5 and α6 (IV) chains were focally detected in the glomerular basement membrane of these patients. These findings indicate that although α5 and α6 (IV) chains are induced in the glomerular basement membrane in autosomal recessive Alport syndrome, their induction does not seem to play a major compensatory role.
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7
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Savva I, Pierides A, Deltas C. RAAS inhibition and the course of Alport syndrome. Pharmacol Res 2016; 107:205-210. [PMID: 26995302 DOI: 10.1016/j.phrs.2016.03.017] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/18/2015] [Revised: 03/04/2016] [Accepted: 03/14/2016] [Indexed: 12/26/2022]
Abstract
Alport syndrome (AS) is a hereditary progressive glomerulonephritis with a high life-time risk for end-stage renal disease (ESRD). Most patients will reach ESRD before the age of 30 years, while a subset of them with milder mutations will do so at older ages, even after 50 years. Frequent extrarenal manifestations are hearing loss and ocular abnormalities. AS is a genetically heterogeneous collagen IV nephropathy, with 85% of the cases caused by mutations in the X-linked COL4A5 gene and the rest by homozygous or compound heterozygous mutations in either the COL4A3 or the COL4A4 gene on chromosome 2q36-37. There is no radical cure for the disease and attempts to use various stem cell therapies in animal models have been met with ambiguous success. However, effective treatment has been accomplished with pharmacological intervention at the renin-angiotensin-aldosterone system (RAAS), first in animal models of AS and more recently in humans. Angiotensin converting enzyme inhibitors (ACEis) and angiotensin receptor blockers (ARBs) have been shown to significantly delay the progression of chronic kidney disease and the onset of ESRD. Also, renin inhibitors and aldosterone blockade were used with positive results, while the combination of ACEis and ARBs was met with mixed success. An important study, the EARLY-PROTECT, aims at evaluating the efficacy of ACEis when administered very early on in children with AS. Novel therapies are also tested experimentally or are under design in animal models by several groups, including the use of amniotic fluid stem cells and synthetic chaperones.
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Affiliation(s)
- Isavella Savva
- Molecular Medicine Research Center and Laboratory of Molecular and Medical Genetics, Department of Biological Sciences, University of Cyprus, Cyprus
| | - Alkis Pierides
- Molecular Medicine Research Center and Laboratory of Molecular and Medical Genetics, Department of Biological Sciences, University of Cyprus, Cyprus; Department of Nephrology, Hippocrateon Hospital, Nicosia, Cyprus
| | - Constantinos Deltas
- Molecular Medicine Research Center and Laboratory of Molecular and Medical Genetics, Department of Biological Sciences, University of Cyprus, Cyprus.
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Moschidou D, Corcelli M, Hau KL, Ekwalla VJ, Behmoaras JV, De Coppi P, David AL, Bou-Gharios G, Cook HT, Pusey CD, Fisk NM, Guillot PV. Human Chorionic Stem Cells: Podocyte Differentiation and Potential for the Treatment of Alport Syndrome. Stem Cells Dev 2016; 25:395-404. [DOI: 10.1089/scd.2015.0305] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Affiliation(s)
- Dafni Moschidou
- Department of Maternal and Fetal Medicine, Institute for Women's Health, University College London, London, United Kingdom
| | - Michelangelo Corcelli
- Department of Maternal and Fetal Medicine, Institute for Women's Health, University College London, London, United Kingdom
| | - Kwan-Leong Hau
- Department of Maternal and Fetal Medicine, Institute for Women's Health, University College London, London, United Kingdom
| | - Victoria J. Ekwalla
- Department of Maternal and Fetal Medicine, Institute for Women's Health, University College London, London, United Kingdom
| | - Jacques V. Behmoaras
- Division of Immunity and Inflammation, Faculty of Medicine, Imperial College London, London, United Kingdom
| | - Paolo De Coppi
- Department of Stem Cells and Regenerative Medicine, Institute of Child Health, University College London, London, United Kingdom
| | - Anna L. David
- Department of Maternal and Fetal Medicine, Institute for Women's Health, University College London, London, United Kingdom
| | - George Bou-Gharios
- Department of Musculoskeletal Biology, Institute of Ageing and Chronic Disease, University of Liverpool, Liverpool, United Kingdom
| | - H. Terence Cook
- Division of Immunity and Inflammation, Faculty of Medicine, Imperial College London, London, United Kingdom
| | - Charles D. Pusey
- Division of Immunity and Inflammation, Faculty of Medicine, Imperial College London, London, United Kingdom
| | - Nicholas M. Fisk
- UQ Centre for Clinical Research, University of Queensland, Brisbane, Queensland, Australia
| | - Pascale V. Guillot
- Department of Maternal and Fetal Medicine, Institute for Women's Health, University College London, London, United Kingdom
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Bataille A, Galichon P, Wetzstein M, Legouis D, Vandermeersch S, Rondeau E, Hertig A. Evaluation of the ability of bone marrow derived cells to engraft the kidney and promote renal tubular regeneration in mice following exposure to cisplatin. Ren Fail 2016; 38:521-9. [PMID: 26905096 DOI: 10.3109/0886022x.2016.1145521] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
It has been suggested that bone marrow derived stem cells have the ability to engraft the kidney and improve the outcome of severe acute kidney injury (AKI) in mice exposed to high doses of cisplatin, providing hope for cancer patients in whom irreversible renal damage occasionally occurs following the use of this highly effective anti-tumor drug. We tested the therapeutic potential of bone marrow derived cells injected during the acute phase (day 3 after cisplatin administration) of experimentally-induced AKI in C57Bl6/J mice, characterized by massive tubular necrosis, apoptosis, and a low proliferation capacity. We failed to show any benefit of bone marrow derived cells versus a regular homogenate of intact renal cells, or normal saline. Using cell tracers and flow cytometry, we demonstrated that bone marrow derived cells did indeed home to the bone marrow of the recipients but failed to settle in the kidney. Conversely, renal cells homed to injured kidneys. However, neither cell therapy protected the animals against cisplatin-induced death. We therefore question the short-term efficacy of bone marrow derived cells used to repair established injuries of the tubular epithelium.
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Affiliation(s)
- Aurélien Bataille
- a Inserm UMR_S 1155, "Rare and Common Kidney Diseases, Matrix Remodelling and Tissue Repair", Tenon Hospital , Paris , France
| | - Pierre Galichon
- a Inserm UMR_S 1155, "Rare and Common Kidney Diseases, Matrix Remodelling and Tissue Repair", Tenon Hospital , Paris , France ;,b Sorbonne Universités , UPMC Université Paris 6 , Paris , France
| | - Morgane Wetzstein
- a Inserm UMR_S 1155, "Rare and Common Kidney Diseases, Matrix Remodelling and Tissue Repair", Tenon Hospital , Paris , France
| | - David Legouis
- a Inserm UMR_S 1155, "Rare and Common Kidney Diseases, Matrix Remodelling and Tissue Repair", Tenon Hospital , Paris , France
| | - Sophie Vandermeersch
- a Inserm UMR_S 1155, "Rare and Common Kidney Diseases, Matrix Remodelling and Tissue Repair", Tenon Hospital , Paris , France
| | - Eric Rondeau
- a Inserm UMR_S 1155, "Rare and Common Kidney Diseases, Matrix Remodelling and Tissue Repair", Tenon Hospital , Paris , France ;,b Sorbonne Universités , UPMC Université Paris 6 , Paris , France
| | - Alexandre Hertig
- a Inserm UMR_S 1155, "Rare and Common Kidney Diseases, Matrix Remodelling and Tissue Repair", Tenon Hospital , Paris , France ;,b Sorbonne Universités , UPMC Université Paris 6 , Paris , France
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11
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Kunter U, Moeller MJ. From Patient to Dish and Back Again: Are We There Yet? J Am Soc Nephrol 2015; 26:1757-9. [PMID: 25568175 DOI: 10.1681/asn.2014111158] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022] Open
Affiliation(s)
- Uta Kunter
- Division of Nephrology and Clinical Immunology, Rheinisch-Westfaelische Technische Hochschule (RWTH) Aachen University, Aachen, Germany
| | - Marcus J Moeller
- Division of Nephrology and Clinical Immunology, Rheinisch-Westfaelische Technische Hochschule (RWTH) Aachen University, Aachen, Germany
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13
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Miner JH, Baigent C, Flinter F, Gross O, Judge P, Kashtan CE, Lagas S, Savige J, Blatt D, Ding J, Gale DP, Midgley JP, Povey S, Prunotto M, Renault D, Skelding J, Turner AN, Gear S. The 2014International Workshop on Alport Syndrome. Kidney Int 2014; 86:679-84. [PMID: 24988067 PMCID: PMC4182137 DOI: 10.1038/ki.2014.229] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2014] [Revised: 03/24/2014] [Accepted: 04/01/2014] [Indexed: 01/15/2023]
Abstract
Alport syndrome, historically referred to as hereditary glomerulonephritis with sensorineural deafness and anterior lenticonus, is a genetic disease of collagen α3α4α5(IV) resulting in renal failure. The collagen α3α4α5(IV) heterotrimer forms a network that is a major component of the kidney glomerular basement membrane (GBM) and basement membranes in the cochlea and eye. Alport syndrome, estimated to affect 1 in 5000–10,000 individuals, is caused by mutations in any one of the three genes that encode the α chain components of the collagen α3α4α5(IV) heterotrimer: COL4A3, COL4A4, and COL4A5. Although angiotensin-converting enzyme inhibition is effective in Alport syndrome patients for slowing progression to end-stage renal disease, it is neither a cure nor an adequate long-term protector. The 2014 International Workshop on Alport Syndrome, held in Oxford, UK, from January 3–5, was organized by individuals and families living with Alport syndrome, in concert with international experts in the clinical, genetic, and basic science aspects of the disease. Stakeholders from diverse communities—patient families, physicians, geneticists, researchers, Pharma, and funding organizations—were brought together so that they could meet and learn from each other and establish strategies and collaborations for the future, with the overall aim of discovering much needed new treatments to prolong kidney function.
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Affiliation(s)
- Jeffrey H Miner
- Renal Division, Washington University School of Medicine, St Louis, Missouri, USA
| | - Colin Baigent
- Clinical Trial Service Unit and Epidemiological Studies Unit, University of Oxford, Oxford, UK
| | - Frances Flinter
- Department of Clinical Genetics, Guy's and St Thomas' NHS Foundation Trust, London, UK
| | - Oliver Gross
- Clinic of Nephrology and Rheumatology, University Medicine Goettingen, Goettingen, Germany
| | - Parminder Judge
- Clinical Trial Service Unit and Epidemiological Studies Unit, University of Oxford, Oxford, UK
| | - Clifford E Kashtan
- Department of Pediatrics, University of Minnesota Medical School, Minneapolis, Minnesota, USA
| | - Sharon Lagas
- Alport Syndrome Foundation, Phoenix, Arizona, USA
| | - Judith Savige
- Melbourne Health, The University of Melbourne, Parkville, Victoria, Australia
| | - Dave Blatt
- Alport Foundation of Australia, Valentine, New South Wales, Australia
| | - Jie Ding
- Pediatric Department, Peking University First Hospital, Beijing, China
| | - Daniel P Gale
- University College London-Center for Nephrology, London, UK
| | - Julian P Midgley
- Department of Pediatrics, Alberta Children's Hospital, Calgary, Alberta, Canada
| | - Sue Povey
- Department of Genetics, Evolution and Environment, University College London, London, UK
| | - Marco Prunotto
- Discovery Technology Department, Pharma Research and Early Development, Basel, Switzerland
| | - Daniel Renault
- Association for Information and Research on Genetic Renal Diseases (AIRG)-France, Paris, France
| | | | - A Neil Turner
- Renal Medicine, Royal Infirmary, University of Edinburgh, Edinburgh, UK
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A mouse Col4a4 mutation causing Alport glomerulosclerosis with abnormal collagen α3α4α5(IV) trimers. Kidney Int 2014; 85:1461-8. [PMID: 24522496 PMCID: PMC4040157 DOI: 10.1038/ki.2013.493] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2013] [Revised: 09/11/2013] [Accepted: 10/03/2013] [Indexed: 12/31/2022]
Abstract
A spontaneous mutation termed bilateral wasting kidneys (bwk) was identified in a colony of NONcNZO recombinant inbred mice. These mice exhibit a rapid increase of urinary albumin at an early age associated with glomerulosclerosis, interstitial nephritis, and tubular atrophy. The mutation was mapped to a location on chromosome 1 containing the Col4a3 and Col4a4 genes, for which mutations in the human orthologs cause the hereditary nephritis Alport syndrome. DNA sequencing identified a G-to-A mutation in the conserved GT splice donor of Col4a4 intron 30, resulting in skipping of exon 30 but maintaining the mRNA reading frame. Protein analyses showed that mutant collagen α3α4α5(IV) trimers were secreted and incorporated into the glomerular basement membrane (GBM), but levels were low, and GBM lesions typical of Alport syndrome were observed. Moving the mutation into the more renal damage-prone DBA/2J and 129S1/SvImJ backgrounds revealed differences in albuminuria and its rate of increase, suggesting an interaction between the Col4a4 mutation and modifier genes. This novel mouse model of Alport syndrome is the only one shown to accumulate abnormal collagen α3α4α5(IV) in the GBM, as also found in a subset of Alport patients. These mice will be valuable for testing potential therapies, for understanding abnormal collagen IV structure and assembly, and for gaining better insights into the mechanisms leading to Alport syndrome, and to the variability in the age of onset and associated phenotypes.
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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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Lin X, Suh JH, Go G, Miner JH. Feasibility of repairing glomerular basement membrane defects in Alport syndrome. J Am Soc Nephrol 2013; 25:687-92. [PMID: 24262794 DOI: 10.1681/asn.2013070798] [Citation(s) in RCA: 61] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
Alport syndrome is a hereditary glomerular disease that leads to kidney failure. It is caused by mutations affecting one of three chains of the collagen α3α4α5(IV) heterotrimer, which forms the major collagen IV network of the glomerular basement membrane (GBM). In the absence of the α3α4α5(IV) network, the α1α1α2(IV) network substitutes, but it is insufficient to maintain normal kidney function. Inhibition of angiotensin-converting enzyme slows progression to kidney failure in patients with Alport syndrome but is not a cure. Restoration of the normal collagen α3α4α5(IV) network in the GBM, by either cell- or gene-based therapy, is an attractive and logical approach toward a cure, but whether or not the abnormal GBM can be repaired once it has formed and is functioning is unknown. Using a mouse model of Alport syndrome and an inducible transgene system, we found that secretion of α3α4α5(IV) heterotrimers by podocytes into a preformed, abnormal, filtering Alport GBM is effective at restoring the missing collagen IV network, slowing kidney disease progression, and extending life span. This proof-of-principle study demonstrates the plasticity of the mature GBM and validates the pursuit of therapeutic approaches aimed at normalizing the GBM to prolong kidney function.
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Danger control programs cause tissue injury and remodeling. Int J Mol Sci 2013; 14:11319-46. [PMID: 23759985 PMCID: PMC3709734 DOI: 10.3390/ijms140611319] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2013] [Revised: 05/12/2013] [Accepted: 05/22/2013] [Indexed: 02/07/2023] Open
Abstract
Are there common pathways underlying the broad spectrum of tissue pathologies that develop upon injuries and from subsequent tissue remodeling? Here, we explain the pathophysiological impact of a set of evolutionary conserved danger control programs for tissue pathology. These programs date back to the survival benefits of the first multicellular organisms upon traumatic injuries by launching a series of danger control responses, i.e., 1. Haemostasis, or clotting to control bleeding; 2. Host defense, to control pathogen entry and spreading; 3. Re-epithelialisation, to recover barrier functions; and 4. Mesenchymal, to repair to regain tissue stability. Taking kidney pathology as an example, we discuss how clotting, inflammation, epithelial healing, and fibrosis/sclerosis determine the spectrum of kidney pathology, especially when they are insufficiently activated or present in an overshooting and deregulated manner. Understanding the evolutionary benefits of these response programs may refine the search for novel therapeutic targets to limit organ dysfunction in acute injuries and in progressive chronic tissue remodeling.
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Abstract
In recent years, it has become apparent that parietal epithelial cells (PECs) play an important role within the renal glomerulus, in particular in diseased conditions. In this review, we examine current knowledge about the role of PECs and their interactions with podocytes in development and under physiological conditions. A particular focus is on the crucial role of PECs and podocytes in two major glomerular disease entities. In rapidly progressive glomerulonephritis, PECs and podocytes proliferate and obstruct the tubular outlet, resulting in loss of the affected nephron. In focal and segmental glomerulosclerosis, PECs become activated and invade a segment of the glomerular tuft via an adhesion. From this entry site, activated PECs displace podocytes and deposit matrix. Thus, activated PECs are involved in inflammatory as well as degenerative glomerular diseases, which both can lead to irreversible loss of renal function.
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Affiliation(s)
- Bart Smeets
- Division of Nephrology and Immunology, Rheinisch-Westfaelische Technische Hochschule, Aachen University Hospital, Aachen, Germany
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Kashtan CE, Ding J, Gregory M, Gross O, Heidet L, Knebelmann B, Rheault M, Licht C. Clinical practice recommendations for the treatment of Alport syndrome: a statement of the Alport Syndrome Research Collaborative. Pediatr Nephrol 2013; 28:5-11. [PMID: 22461141 PMCID: PMC3505543 DOI: 10.1007/s00467-012-2138-4] [Citation(s) in RCA: 84] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/09/2011] [Revised: 01/29/2012] [Accepted: 01/31/2012] [Indexed: 12/21/2022]
Abstract
We present clinical practice recommendations for the treatment of children with Alport syndrome who are not enrolled in clinical trials. Our goal is to promote early initiation of a standard therapeutic approach that will facilitate assessment of the safety and efficacy of the protocol. The treatment protocol is based on the reduction of proteinuria, intraglomerular pressure, and renal fibrosis via interference with the renin-angiotensin-aldosterone system.
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Affiliation(s)
- Clifford E. Kashtan
- Department of Pediatrics, Division of Pediatric Nephrology, University of Minnesota Medical School, Minneapolis, MN USA
| | - Jie Ding
- Pediatric Department, Peking University First Hospital, Beijing, People’s Republic of China
| | - Martin Gregory
- Division of Nephrology, University of Utah Health Sciences Center, Salt Lake City, UT USA
| | - Oliver Gross
- Department of Nephrology and Rheumatology, University Medicine Goettingen, Goettingen, Germany
| | - Laurence Heidet
- Centre de référence pour les Maladies Rénales Héréditaires de l’Enfant et de l’Adulte (MARHEA) and Service de Néphrologie Pédiatrique, Hôpital Necker-Enfants malades, Paris, France
| | - Bertrand Knebelmann
- Centre de référence pour les Maladies Rénales Héréditaires de l’Enfant et de l’Adulte (MARHEA) and Service de Néphrologie Pédiatrique, Hôpital Necker-Enfants malades, Paris, France
| | - Michelle Rheault
- Department of Pediatrics, Division of Pediatric Nephrology, University of Minnesota Medical School, Minneapolis, MN USA
| | - Christoph Licht
- The Hospital for Sick Children, Division of Nephrology, Toronto, Canada
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Kruegel J, Rubel D, Gross O. Alport syndrome--insights from basic and clinical research. Nat Rev Nephrol 2012; 9:170-8. [PMID: 23165304 DOI: 10.1038/nrneph.2012.259] [Citation(s) in RCA: 162] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
In 1927, Arthur C. Alport first published his description of a triad of symptoms in a family with hereditary congenital haemorrhagic nephritis, deafness and ocular changes. A few years after his death, this group of symptoms was renamed Alport syndrome. To this day, Alport syndrome still inevitably leads to end-stage renal disease and the need for renal replacement therapy, starting in young adulthood. During the past two decades, research into this rare disease has focused on the effects of mutations in collagen type IV and the role of changes in podocytes and the glomerular basement membrane that lead to early kidney fibrosis. Animal models of Alport syndrome also demonstrate the pathogenetic importance of interactions between podocytes and the extracellular matrix. Such models might also help researchers to answer basic questions about podocyte function and the development of fibrosis, and to develop new therapeutic approaches that might be of use in other kidney diseases. In this Review, we discuss the latest basic and clinical research on Alport syndrome, focusing on the roles of podocyte pathology and the extracellular matrix. We also highlight early diagnosis and treatment options for young patients with this disorder.
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Affiliation(s)
- Jenny Kruegel
- Department of Nephrology and Rheumatology, University Medicine Göttingen, Robert-Koch-Straße 40, 37075 Göttingen, Germany
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Temme J, Kramer A, Jager KJ, Lange K, Peters F, Müller GA, Kramar R, Heaf JG, Finne P, Palsson R, Reisæter AV, Hoitsma AJ, Metcalfe W, Postorino M, Zurriaga O, Santos JP, Ravani P, Jarraya F, Verrina E, Dekker FW, Gross O. Outcomes of male patients with Alport syndrome undergoing renal replacement therapy. Clin J Am Soc Nephrol 2012; 7:1969-76. [PMID: 22997344 DOI: 10.2215/cjn.02190312] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
BACKGROUND AND OBJECTIVES Patients with the hereditary disease Alport syndrome commonly require renal replacement therapy (RRT) in the second or third decade of life. This study compared age at onset of RRT, renal allograft, and patient survival in men with Alport syndrome receiving various forms of RRT (peritoneal dialysis, hemodialysis, or transplantation) with those of men with other renal diseases. DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS Patients with Alport syndrome receiving RRT identified from 14 registries in Europe were matched to patients with other renal diseases. A linear spline model was used to detect changes in the age at start of RRT over time. Kaplan-Meier method and Cox regression analysis were used to examine patient and graft survival. RESULTS Age at start of RRT among patients with Alport syndrome remained stable during the 1990s but increased by 6 years between 2000-2004 and 2005-2009. Survival of patients with Alport syndrome requiring dialysis or transplantation did not change between 1990 and 2009. However, patients with Alport syndrome had better renal graft and patient survival than matched controls. Numbers of living-donor transplantations were lower in patients with Alport syndrome than in matched controls. CONCLUSIONS These data suggest that kidney failure in patients with Alport syndrome is now being delayed compared with previous decades. These patients appear to have superior patient survival while undergoing dialysis and superior patient and graft survival after deceased-donor kidney transplantation compared with patients receiving RRT because of other causes of kidney failure.
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Affiliation(s)
- Johanna Temme
- Dept Nephrology&Rheumatology, University Medical Center Göttingen, Göttingen, Germany
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Anders HJ. Four danger response programs determine glomerular and tubulointerstitial kidney pathology: clotting, inflammation, epithelial and mesenchymal healing. Organogenesis 2012; 8:29-40. [PMID: 22692229 PMCID: PMC3429510 DOI: 10.4161/org.20342] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
Renal biopsies commonly display tissue remodeling with a combination of many different findings. In contrast to trauma, kidney remodeling largely results from intrinsic responses, but why? Distinct danger response programs were positively selected throughout evolution to survive traumatic injuries and to regenerate tissue defects. These are: (1) clotting to avoid major bleeding, (2) immunity to control infection, (3) epithelial repair and (4) mesenchymal repair. Collateral damages are acceptable for the sake of host survival but causes for kidney injury commonly affect the kidneys in a diffuse manner. This way, coagulation, inflammation, deregulated epithelial healing or fibrosis contribute to kidney remodeling. Here, I focus on how these ancient danger response programs determine renal pathology mainly because they develop in a deregulated manner, either as insufficient or overshooting processes that modulate each other. From a therapeutic point of view, immunopathology can be prevented by suppressing sterile renal inflammation, a useless atavism with devastating consequences. In addition, it appears as an important goal for the future to promote podocyte and tubular epithelial cell repair, potentially by stimulating the differentiation of their newly discovered intrarenal progenitor cells. By contrast, it is still unclear whether selectively targeting renal fibrogenesis can preserve or bring back lost renal parenchyma, which would be required to maintain or improve kidney function. Thus, renal pathology results from ancient danger responses that evolved because of their evolutional benefits upon trauma. Understanding these causalities may help to shape the search for novel treatments for kidney disease patients.
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Affiliation(s)
- Hans-Joachim Anders
- Nephrologisches Zentrum; Medizinische Klinik und Poliklinik IV; Klinikum der Universität; München, Germany.
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Sedrakyan S, Da Sacco S, Milanesi A, Shiri L, Petrosyan A, Varimezova R, Warburton D, Lemley KV, De Filippo RE, Perin L. Injection of amniotic fluid stem cells delays progression of renal fibrosis. J Am Soc Nephrol 2012; 23:661-73. [PMID: 22302195 DOI: 10.1681/asn.2011030243] [Citation(s) in RCA: 103] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
Injection of amniotic fluid stem cells ameliorates the acute phase of acute tubular necrosis in animals by promoting proliferation of injured tubular cells and decreasing apoptosis, but whether these stem cells could be of benefit in CKD is unknown. Here, we used a mouse model of Alport syndrome, Col4a5(-/-) mice, to determine whether amniotic fluid stem cells could modify the course of progressive renal fibrosis. Intracardiac administration of amniotic fluid stem cells before the onset of proteinuria delayed interstitial fibrosis and progression of glomerular sclerosis, prolonged animal survival, and ameliorated the decline in kidney function. Treated animals exhibited decreased recruitment and activation of M1-type macrophages and a higher proportion of M2-type macrophages, which promote tissue remodeling. Amniotic fluid stem cells did not differentiate into podocyte-like cells and did not stimulate production of the collagen IVa5 needed for normal formation and function of the glomerular basement membrane. Instead, the mechanism of renal protection was probably the paracrine/endocrine modulation of both profibrotic cytokine expression and recruitment of macrophages to the interstitial space. Furthermore, injected mice retained a normal number of podocytes and had better integrity of the glomerular basement membrane compared with untreated Col4a5(-/-) mice. Inhibition of the renin-angiotensin system by amniotic fluid stem cells may contribute to these beneficial effects. In conclusion, treatment with amniotic fluid stem cells may be beneficial in kidney diseases characterized by progressive renal fibrosis.
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Affiliation(s)
- Sargis Sedrakyan
- GOFARR Laboratory for Organ Regenerative Research and Cell Therapeutics, Children's Hospital Los Angeles, Division of Urology, Saban Research Institute, University of Southern California, Los Angeles, California 90027, USA
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Little MH, Rae FK. Review article: Potential cellular therapies for renal disease: can we translate results from animal studies to the human condition? Nephrology (Carlton) 2009. [PMID: 19712255 DOI: 10.1111/j.1440-1797.2009.01144.x] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
The incidence of chronic kidney disease is increasing worldwide, prompting considerable research into potential regenerative therapies. These have included studies to determine whether an endogenous renal stem cell exists in the postnatal kidney and whether non-renal adult stem cells, such as mesenchymal stem cell, can ameliorate renal damage. Such stem cells will either need to be recruited to the damaged kidney to repair the damage in situ or be differentiated into the desired cell type and delivered into the damaged kidney to subsequently elicit repair without maldifferentiation. To date, these studies have largely been performed using experimental and genetic models of renal damage in rodents. The translation of such research into a therapy applicable to human disease faces many challenges. In this review, we examine which animal models have been used to evaluate potential cellular therapies and how valid these are to human chronic kidney disease.
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Affiliation(s)
- Melissa H Little
- Institute for Molecular Bioscience, The University of Queensland, St. Lucia, Queensland, Australia.
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LeBleu V, Sugimoto H, Mundel TM, Gerami-Naini B, Finan E, Miller CA, Gattone VH, Lu L, Shield CF, Folkman J, Kalluri R. Stem cell therapies benefit Alport syndrome. J Am Soc Nephrol 2009; 20:2359-70. [PMID: 19833902 DOI: 10.1681/asn.2009010123] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
Patients with Alport syndrome progressively lose renal function as a result of defective type IV collagen in their glomerular basement membrane. In mice lacking the alpha3 chain of type IV collagen (Col4A3 knockout mice), a model for Alport syndrome, transplantation of wild-type bone marrow repairs the renal disease. It is unknown whether cell-based therapies that do not require transplantation have similar potential. Here, infusion of wild-type bone marrow-derived cells into unconditioned, nonirradiated Col4A3 knockout mice during the late stage of disease significantly improved renal histology and function. Furthermore, transfusion of unfractionated wild-type blood into unconditioned, nonirradiated Col4A3 knockout mice improved the renal phenotype and significantly improved survival. Injection of mouse and human embryonic stem cells into Col4A3 knockout mice produced similar results. Regardless of treatment modality, the improvement in the architecture of the glomerular basement membrane is associated with de novo expression of the alpha3(IV) chain. These data provide further support for testing cell-based therapies for Alport syndrome.
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Affiliation(s)
- Valerie LeBleu
- Division of Matrix Biology, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, MA 02215, USA
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Abstract
In 1990, the role of basement membranes in human disease was established by the identification of COL4A5 mutations in Alport's syndrome. Since then, the number of diseases caused by mutations in basement membrane components has steadily increased as has our understanding of the roles of basement membranes in organ development and function. However, many questions remain as to the molecular and cellular consequences of these mutations and the way in which they lead to the observed disease phenotypes. Despite this, exciting progress has recently been made with potential treatment options for some of these so far incurable diseases.
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