1
|
Mabillard H, Ryan R, Tzoumas N, Gear S, Sayer JA. Explaining Alport syndrome-lessons from the adult nephrology clinic. JOURNAL OF RARE DISEASES (BERLIN, GERMANY) 2024; 3:14. [PMID: 38745975 PMCID: PMC11088994 DOI: 10.1007/s44162-024-00036-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/24/2023] [Accepted: 02/15/2024] [Indexed: 05/16/2024]
Abstract
Alport syndrome is a genetic kidney disease that causes worsening of kidney function over time, often progressing to kidney failure. Some types of Alport syndrome cause other symptoms and signs, including hearing loss and eye abnormalities. Research now indicates that Alport syndrome (autosomal dominant inheritance) is the most common form. Alport syndrome can have X-linked or a rare form of autosomal recessive inheritance. Traditionally, a kidney biopsy was used to diagnose Alport syndrome, but genetic testing provides a more precise and less invasive means of diagnosis and reveals the underlying pattern of inheritance. At present, there are no specific curative treatments for Alport syndrome however there is a strong international effort in pursuit of future therapies. Currently, angiotensin-converting enzyme inhibitors (ACEi), or an angiotensin receptor blocker (ARB) if a patient cannot tolerate an ACEi, slow down the progression of kidney disease and can delay the onset of kidney failure by years. There are other potential treatments in research that potentially can help delay the onset of kidney issues. Early treatment of patients and identification of their at-risk relatives is a priority. People living with Alport syndrome and their doctors now benefit from an active international research community working on translating further treatments into clinical practice and providing up-to-date clinical guidelines.
Collapse
Affiliation(s)
- Holly Mabillard
- Renal Services, Newcastle Upon Tyne Hospitals NHS Foundation Trust, Newcastle Upon Tyne, UK
- Translational and Clinical Research Institute, Faculty of Medical Sciences, Newcastle University, Central Parkway, Newcastle Upon Tyne, UK
| | - Rebecca Ryan
- Renal Services, Newcastle Upon Tyne Hospitals NHS Foundation Trust, Newcastle Upon Tyne, UK
| | - Nik Tzoumas
- Faculty of Medical Sciences, Biosciences Institute, Newcastle University, Central Parkway, Newcastle Upon Tyne, UK
- Sunderland Eye Infirmary, Sunderland, UK
| | - Susie Gear
- Alport UK, Cirencester, Gloucestershire, UK
| | - John A. Sayer
- Renal Services, Newcastle Upon Tyne Hospitals NHS Foundation Trust, Newcastle Upon Tyne, UK
- Translational and Clinical Research Institute, Faculty of Medical Sciences, Newcastle University, Central Parkway, Newcastle Upon Tyne, UK
- NIHR Newcastle Biomedical Research Centre, Newcastle Upon Tyne, UK
| |
Collapse
|
2
|
Chavez E, Goncalves S, Rheault MN, Fornoni A. Alport Syndrome. ADVANCES IN KIDNEY DISEASE AND HEALTH 2024; 31:170-179. [PMID: 39004457 DOI: 10.1053/j.akdh.2024.02.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/19/2023] [Revised: 02/10/2024] [Accepted: 02/28/2024] [Indexed: 07/16/2024]
Abstract
Alport syndrome (AS) is characterized by progressive kidney failure, hematuria, sensorineural hearing loss, and ocular abnormalities. Pathogenic variants in the COL4A3-5 genes result in a defective deposition of the collagen IV α3α4α5 protomers in the basement membranes of the glomerulus in the kidney, the cochlea in the ear and the cornea, lens capsule and retina in the eye. The presence of a large variety of COL4A3-5 gene(s) pathogenetic variants irrespective of the mode of inheritance (X-linked, autosomal recessive, autosomal dominant, or digenic) with and without syndromic features is better defined as the "Alport spectrum disorder", and represents the most common cause of genetic kidney disease and the second most common cause of genetic kidney failure. The clinical course and prognosis of individuals with AS is highly variable. It is influenced by gender, mode of inheritance, affected gene(s), type of genetic mutation, and genetic modifiers. This review article will discuss the epidemiology, classification, pathogenesis, diagnosis, clinical course with genotype-phenotype correlations, and current and upcoming treatment of patients with AS. It will also review current recommendations with respect to when to evaluate for hearing loss or ophthalmologic abnormalities.
Collapse
Affiliation(s)
- Efren Chavez
- Katz Family Division of Nephrology and Hypertension, Department of Medicine, University of Miami Miller School of Medicine, Miami, FL.
| | - Stefania Goncalves
- Department of Otolaryngology-Head and Neck Surgery, University of Miami Miller School of Medicine, University of Miami Ear Institute, Miami, FL
| | - Michelle N Rheault
- Department of Pediatrics, University of Minnesota Masonic Children's Hospital, Minneapolis, MN
| | - Alessia Fornoni
- Katz Family Division of Nephrology and Hypertension, Department of Medicine, University of Miami Miller School of Medicine, Miami, FL; Peggy and Harold Katz Family Drug Discovery Center, University of Miami Miller School of Medicine, Miami, FL.
| |
Collapse
|
3
|
Williams MJ, Halabi CM, Patel HM, Joseph Z, McCommis K, Weinheimer C, Kovacs A, Lima F, Finck B, Malluche H, Hruska KA. In chronic kidney disease altered cardiac metabolism precedes cardiac hypertrophy. Am J Physiol Renal Physiol 2024; 326:F751-F767. [PMID: 38385175 DOI: 10.1152/ajprenal.00416.2023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2023] [Revised: 02/15/2024] [Accepted: 02/15/2024] [Indexed: 02/23/2024] Open
Abstract
Conduit arterial disease in chronic kidney disease (CKD) is an important cause of cardiac complications. Cardiac function in CKD has not been studied in the absence of arterial disease. In an Alport syndrome model bred not to have conduit arterial disease, mice at 225 days of life (dol) had CKD equivalent to humans with CKD stage 4-5. Parathyroid hormone (PTH) and FGF23 levels were one log order elevated, circulating sclerostin was elevated, and renal activin A was strongly induced. Aortic Ca levels were not increased, and vascular smooth muscle cell (VSMC) transdifferentiation was absent. The CKD mice were not hypertensive, and cardiac hypertrophy was absent. Freshly excised cardiac tissue respirometry (Oroboros) showed that ADP-stimulated O2 flux was diminished from 52 to 22 pmol/mg (P = 0.022). RNA-Seq of cardiac tissue from CKD mice revealed significantly decreased levels of cardiac mitochondrial oxidative phosphorylation genes. To examine the effect of activin A signaling, some Alport mice were treated with a monoclonal Ab to activin A or an isotype-matched IgG beginning at 75 days of life until euthanasia. Treatment with the activin A antibody (Ab) did not affect cardiac oxidative phosphorylation. However, the activin A antibody was active in the skeleton, disrupting the effect of CKD to stimulate osteoclast number, eroded surfaces, and the stimulation of osteoclast-driven remodeling. The data reported here show that cardiac mitochondrial respiration is impaired in CKD in the absence of conduit arterial disease. This is the first report of the direct effect of CKD on cardiac respiration.NEW & NOTEWORTHY Heart disease is an important morbidity of chronic kidney disease (CKD). Hypertension, vascular stiffness, and vascular calcification all contribute to cardiac pathophysiology. However, cardiac function in CKD devoid of vascular disease has not been studied. Here, in an animal model of human CKD without conduit arterial disease, we analyze cardiac respiration and discover that CKD directly impairs cardiac mitochondrial function by decreasing oxidative phosphorylation. Protection of cardiac oxidative phosphorylation may be a therapeutic target in CKD.
Collapse
Affiliation(s)
- Matthew J Williams
- Renal Division, Department of Pediatrics, Washington University in St. Louis, St. Louis, Missouri, United States
| | - Carmen M Halabi
- Renal Division, Department of Pediatrics, Washington University in St. Louis, St. Louis, Missouri, United States
| | - Hiral M Patel
- Renal Division, Department of Pediatrics, Washington University in St. Louis, St. Louis, Missouri, United States
| | - Zachary Joseph
- Renal Division, Department of Pediatrics, Washington University in St. Louis, St. Louis, Missouri, United States
| | - Kyle McCommis
- Geriatrics and Nutritional Science Division, Department of Medicine, Washington University in St. Louis, St. Louis, Missouri, United States
| | - Carla Weinheimer
- Cardiology Division, Department of Medicine, Washington University in St. Louis, St. Louis, Missouri, United States
| | - Attila Kovacs
- Cardiology Division, Department of Medicine, Washington University in St. Louis, St. Louis, Missouri, United States
| | - Florence Lima
- Renal Division, Department of Medicine, University of Kentucky, Lexington, Kentucky, United States
| | - Brian Finck
- Geriatrics and Nutritional Science Division, Department of Medicine, Washington University in St. Louis, St. Louis, Missouri, United States
| | - Hartmut Malluche
- Renal Division, Department of Medicine, University of Kentucky, Lexington, Kentucky, United States
| | - Keith A Hruska
- Renal Division, Department of Pediatrics, Washington University in St. Louis, St. Louis, Missouri, United States
- Renal Division, Department of Medicine, Washington University in St. Louis, St. Louis, Missouri, United States
- Department of Cell Biology, Washington University in St. Louis, St. Louis, Missouri, United States
| |
Collapse
|
4
|
Puapatanakul P, Miner JH. Alport syndrome and Alport kidney diseases - elucidating the disease spectrum. Curr Opin Nephrol Hypertens 2024; 33:283-290. [PMID: 38477333 PMCID: PMC10990029 DOI: 10.1097/mnh.0000000000000983] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/14/2024]
Abstract
PURPOSE OF REVIEW With the latest classification, variants in three collagen IV genes, COL4A3 , COL4A4 , and COL4A5 , represent the most prevalent genetic kidney disease in humans, exhibiting diverse, complex, and inconsistent clinical manifestations. This review breaks down the disease spectrum and genotype-phenotype correlations of kidney diseases linked to genetic variants in these genes and distinguishes "classic" Alport syndrome (AS) from the less severe nonsyndromic genetically related nephropathies that we suggest be called "Alport kidney diseases". RECENT FINDINGS Several research studies have focused on the genotype-phenotype correlation under the latest classification scheme of AS. The historic diagnoses of "benign familial hematuria" and "thin basement membrane nephropathy" linked to heterozygous variants in COL4A3 or COL4A4 are suggested to be obsolete, but instead classified as autosomal AS by recent expert consensus due to a significant risk of disease progression. SUMMARY The concept of Alport kidney disease extends beyond classic AS. Patients carrying pathogenic variants in any one of the COL4A3/A4/A5 genes can have variable phenotypes ranging from completely normal/clinically unrecognizable, hematuria without or with proteinuria, or progression to chronic kidney disease and kidney failure, depending on sex, genotype, and interplays of other genetic as well as environmental factors.
Collapse
Affiliation(s)
- Pongpratch Puapatanakul
- Division of Nephrology, Department of Medicine, Washington University School of Medicine, St. Louis, Missouri, USA
- Division of Nephrology, Department of Medicine, Faculty of Medicine, Chulalongkorn University, Bangkok, Thailand
| | - Jeffrey H. Miner
- Division of Nephrology, Department of Medicine, Washington University School of Medicine, St. Louis, Missouri, USA
| |
Collapse
|
5
|
Zisis V, Dimitrios A, Kasimatis E, Vakirlis E, Poulopoulos A. Alport Syndrome and Oral Mucous Membrane Pemphigoid: An Interesting Case. Cureus 2023; 15:e41519. [PMID: 37551211 PMCID: PMC10404443 DOI: 10.7759/cureus.41519] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/07/2023] [Indexed: 08/09/2023] Open
Abstract
Alport syndrome (AS) is a hereditary progressive glomerular disease associated with sensorineural hearing loss and ocular abnormalities. It is attributed to the altered structure and the subsequent dysfunction of the glomerular basement membrane (GBM) due to the mutated type IV collagen a3/a4/a5 chains. It may emerge either as an X-linked disease, the most common, or as an autosomal disease, both recessive and dominant. A female patient, 26 years old, came in 2023 to the Department of Oral Medicine/ Pathology, Dental School, Aristotle University of Thessaloniki, complaining about pain and a burning sensation in her right cheek. Her medical history revealed the diagnosis of Alport syndrome in 2016 and kidney transplantation in 2022 with extensive post-transplantation drug administration. The clinical examination revealed an ulcer, partially covered by a pseudomembrane, on the oral mucosa of the right cheek, surrounded by an erythematous border. A biopsy was taken, and the histopathological examination showed the oral manifestation of mucous membrane pemphigoid. After communicating with the attending nephrologist, the prescription of methylprednisolone was decided, and the lesions receded. The differential diagnosis included both AS-induced pemphigoid and drug-induced pemphigoid. The thorough medical history, detailed clinical investigation, lesion biopsy, and collaboration of different dental and medical specialties constitute necessary prerequisites for a successful treatment, even in immunosuppressed patients.
Collapse
Affiliation(s)
- Vasileios Zisis
- Oral Medicine/ Pathology, Aristotle University of Thessaloniki, Thessaloniki, GRC
| | - Andreadis Dimitrios
- Oral Medicine/Pathology, Aristotle University of Thessaloniki, Thessaloniki, GRC
| | | | - Eustratios Vakirlis
- Dermatology, Ippokrateio General Hospital of Thessaloniki, Thessaloniki, GRC
| | | |
Collapse
|
6
|
Gregorio VD, Caparali B, Shojaei A, Ricardo S, Barua M. Alport Syndrome: Clinical Spectrum and Therapeutic Advances. Kidney Med 2023; 5:100631. [PMID: 37122389 PMCID: PMC10131117 DOI: 10.1016/j.xkme.2023.100631] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/08/2023] Open
Abstract
Alport syndrome is a hereditary disorder characterized by kidney disease, ocular abnormalities, and sensorineural hearing loss. Work in understanding the cause of Alport syndrome and the molecular composition of the glomerular basement membrane ultimately led to the identification of COL4A3, COL4A4 (both on chromosome 2q36), and COL4A5 (chromosome Xq22), encoding the α3, α4, and α5 chains of type IV collagen, as the responsible genes. Subsequent studies suggested that autosomal recessive Alport syndrome and males with X-linked Alport syndrome have more severe disease, whereas autosomal dominant Alport syndrome and females with X-linked Alport syndrome have more variability. Variant type is also influential-protein-truncating variants in autosomal recessive Alport syndrome or males with X-linked Alport syndrome often present with severe symptoms, characterized by kidney failure, extrarenal manifestations, and lack of the α3-α4-α5(IV) network. By contrast, mild-moderate forms from missense variants display α3-α4-α5(IV) in the glomerular basement membrane and are associated with protracted kidney involvement without extrarenal manifestations. Regardless of type, therapeutic intervention for kidney involvement is focused on early initiation of angiotensin-converting enzyme inhibitors. There are several therapies under investigation including sodium/glucose cotransporter 2 inhibitors, aminoglycoside analogs, endothelin type A antagonists, lipid-modifying drugs, and hydroxychloroquine, although targeting the underlying defect through gene therapy remains in preclinical stages.
Collapse
|
7
|
Chavez E, Rodriguez J, Drexler Y, Fornoni A. Novel Therapies for Alport Syndrome. Front Med (Lausanne) 2022; 9:848389. [PMID: 35547199 PMCID: PMC9081811 DOI: 10.3389/fmed.2022.848389] [Citation(s) in RCA: 19] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2022] [Accepted: 03/14/2022] [Indexed: 12/14/2022] Open
Abstract
Alport syndrome (AS) is a hereditary kidney disease associated with proteinuria, hematuria and progressive kidney failure. It is characterized by a defective glomerular basement membrane caused by mutations in type IV collagen genes COL4A3/A4/A5 which result in defective type IV collagen α3, α4, or α5 chains, respectively. Alport syndrome has three different patterns of inheritance: X-linked, autosomal and digenic. In a study of CKD of unknown etiology type IV collagen gene mutations accounted for the majority of the cases of hereditary glomerulopathies which suggests that AS is often underrecognized. The natural history and prognosis in patients with AS is variable and is determined by genetics and environmental factors. At present, no preventive or curative therapies exist for AS. Current treatment includes the use of renin-angiotensin-aldosterone system inhibitors which slow progression of kidney disease and prolong life expectancy. Ramipril was found in retrospective studies to delay the onset of ESKD and was recently demonstrated to be safe and effective in children and adolescents, supporting that early initiation of Renin Angiotensin Aldosterone System (RAAS) blockade is very important. Mineralocorticoid receptor blockers might be favorable for patients who develop "aldosterone breakthrough." While the DAPA-CKD trial suggests a beneficial effect of SGLT2 inhibitors in CKD of non-metabolic origin, only a handful of patients had Alport in this cohort, and therefore conclusions can't be extrapolated for the treatment of AS with SGLT2 inhibitors. Advances in our understanding on the pathogenesis of Alport syndrome has culminated in the development of innovative therapeutic approaches that are currently under investigation. We will provide a brief overview of novel therapeutic targets to prevent progression of kidney disease in AS. Our review will include bardoxolone methyl, an oral NRf2 activator; lademirsen, an anti-miRNA-21 molecule; sparsentan, dual endothelin type A receptor (ETAR) and angiotensin 1 receptor inhibitor; atrasentan, oral selective ETAR inhibitor; lipid-modifying agents, including cholesterol efflux transporter ATP-binding cassette A1 (ABCA1) inducers, discoidin domain receptor 1 (DDR1) inhibitors and osteopontin blocking agents; the antimalarial drug hydroxychloroquine; the antiglycemic drug metformin and the active vitamin D analog paricalcitol. Future genomic therapeutic strategies such as chaperone therapy, genome editing and stem cell therapy will also be discussed.
Collapse
Affiliation(s)
- Efren Chavez
- Katz Family Division of Nephrology and Hypertension, Department of Medicine, University of Miami Miller School of Medicine, Miami, FL, United States
| | - Juanly Rodriguez
- Katz Family Division of Nephrology and Hypertension, Department of Medicine, University of Miami Miller School of Medicine, Miami, FL, United States
| | - Yelena Drexler
- Katz Family Division of Nephrology and Hypertension, Department of Medicine, University of Miami Miller School of Medicine, Miami, FL, United States
| | - Alessia Fornoni
- Katz Family Division of Nephrology and Hypertension, Department of Medicine, University of Miami Miller School of Medicine, Miami, FL, United States.,Peggy and Harold Katz Family Drug Discovery Center, University of Miami Miller School of Medicine, Miami, FL, United States
| |
Collapse
|
8
|
Value of electron microscopy in the pathological diagnosis of native kidney biopsies in children. Pediatr Nephrol 2020; 35:2285-2295. [PMID: 32620982 DOI: 10.1007/s00467-020-04681-6] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/19/2020] [Revised: 06/15/2020] [Accepted: 06/17/2020] [Indexed: 10/23/2022]
Abstract
BACKGROUND Pediatric native kidney diseases are common worldwide. The pathological diagnosis of kidney lesions is crucial for clinical treatment and prognosis. The aim of the current study was therefore to evaluate the value of electron microscopy (EM) to the final diagnosis of native kidney biopsies in children. METHODS A retrospective evaluation of 855 pediatric kidney biopsies obtained from the Department of Pediatrics in Peking University First Hospital between November 2010 and December 2017 was performed to assess the contribution of EM to the final diagnosis. RESULTS The role of EM in the final diagnosis was determined to be crucial in 300 cases (35.1%), important in 280 cases (32.7%), and auxiliary in 275 cases (32.2%). EM is considered most valuable in a large percentage of glomerular diseases, mainly including minimal change disease, early-stage membranous nephropathy, postinfectious glomerulonephritis, Alport syndrome, thin basement membrane nephropathy, and thrombotic microangiopathy. EM also provided helpful diagnostic information in cases of focal segmental glomerulosclerosis, lupus nephritis, IgA nephropathy, and IgA vasculitis (Henoch-Schonlein purpura nephritis). Additionally, EM was crucial in 90.0% of cases of subtle pathological changes observed with light microscopy (LM) and immunofluorescence (IF) and in 69.3% of the IF-negative specimens. Patients with nephrotic syndrome or hematuria also benefit from ultrastructural examination. CONCLUSIONS The present study demonstrated the crucial or important role of EM in the diagnosis of a majority of native kidney biopsies in children. The application of EM should be integrated together with LM and IF as a routine method of assessing pediatric kidney specimens. Graphical abstract.
Collapse
|
9
|
Murray SL, Fennelly NK, Doyle B, Lynch SA, Conlon PJ. Integration of genetic and histopathology data in interpretation of kidney disease. Nephrol Dial Transplant 2020; 35:1113-1132. [PMID: 32777081 DOI: 10.1093/ndt/gfaa176] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2020] [Indexed: 12/22/2022] Open
Abstract
For many years renal biopsy has been the gold standard for diagnosis in many forms of kidney disease. It provides rapid, accurate and clinically useful information in most individuals with kidney disease. However, in recent years, other diagnostic modalities have become available that may provide more detailed and specific diagnostic information in addition to, or instead of, renal biopsy. Genomics is one of these modalities. Previously prohibitively expensive and time consuming, it is now increasingly available and practical in a clinical setting for the diagnosis of inherited kidney disease. Inherited kidney disease is a significant cause of kidney disease, in both the adult and paediatric populations. While individual inherited kidney diseases are rare, together they represent a significant burden of disease. Because of the heterogenicity of inherited kidney disease, diagnosis and management can be a challenge and often multiple diagnostic modalities are needed to arrive at a diagnosis. We present updates in genomic medicine for renal disease, how genetic testing integrates with our knowledge of renal histopathology and how the two modalities may interact to enhance patient care.
Collapse
Affiliation(s)
- Susan L Murray
- Department of Nephrology and Transplantation, Beaumont Hospital, Dublin, Ireland.,Department of Medicine, Royal College of Surgeons, Dublin, Ireland
| | | | - Brendan Doyle
- Department of Pathology, Beaumont Hospital, Dublin, Ireland
| | - Sally Ann Lynch
- National Rare Disease Office Mater Hospital Dublin, Dublin, Ireland
| | - Peter J Conlon
- Department of Nephrology and Transplantation, Beaumont Hospital, Dublin, Ireland.,Department of Medicine, Royal College of Surgeons, Dublin, Ireland
| |
Collapse
|
10
|
Suh SH, Choi HS, Kim CS, Kim IJ, Ma SK, Scholey JW, Kim SW, Bae EH. Olmesartan Attenuates Kidney Fibrosis in a Murine Model of Alport Syndrome by Suppressing Tubular Expression of TGFβ. Int J Mol Sci 2019; 20:ijms20153843. [PMID: 31390839 PMCID: PMC6695622 DOI: 10.3390/ijms20153843] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2019] [Revised: 08/02/2019] [Accepted: 08/04/2019] [Indexed: 12/21/2022] Open
Abstract
Despite the wide use of angiotensin II receptor blockers in the treatment of Alport syndrome (AS), the mechanism as to how angiotensin II receptor blockers prevent interstitial fibrosis remains unclear. Here, we report that treatment of olmesartan effectively targets the feedback loop between the renin–angiotensin system (RAS) and transforming growth factor β (TGFβ) signals in tubular epithelial cells and preserves renal angiotensin-converting enzyme 2 (ACE2) expression in the kidney of Col4a3–/– mice, a murine model of experimental AS. Morphology analyses revealed amelioration of kidney fibrosis in Col4a3–/– mice by olmesartan treatment. Upregulation of TGFβ and activation of its downstream in Col4a3–/– mice were attenuated by olmesartan in Col4a3–/– mice. Intriguingly, TGFβ expression was preferentially upregulated in damaged tubular epithelial cells in Col4a3–/– mice. Concurrent upregulation of TNFα-converting enzyme and downregulation of ACE2 suggested RAS activation in Col4a3–/– mice, which was prevented by olmesartan. Mechanistically, olmesartan suppressed TGFβ-induced RAS activation in tubular epithelial cells in vitro. Collectively, we concluded that olmesartan effectively suppresses the progression of tubulointerstitial fibrosis in AS by interrupting RAS-TGFβ feedback loop to counterbalance intrarenal RAS activation.
Collapse
Affiliation(s)
- Sang Heon Suh
- Department of Internal Medicine, Chonnam National University Hospital, Gwangju 61469, Korea
| | - Hong Sang Choi
- Department of Internal Medicine, Chonnam National University Hospital, Gwangju 61469, Korea
| | - Chang Seong Kim
- Department of Internal Medicine, Chonnam National University Hospital, Gwangju 61469, Korea
| | - In Jin Kim
- Department of Internal Medicine, Chonnam National University Hospital, Gwangju 61469, Korea
| | - Seong Kwon Ma
- Department of Internal Medicine, Chonnam National University Hospital, Gwangju 61469, Korea
| | - James W Scholey
- Department of Medicine and Institute of Medical Science, University of Toronto, Toronto M5S, Canada
| | - Soo Wan Kim
- Department of Internal Medicine, Chonnam National University Hospital, Gwangju 61469, Korea.
| | - Eun Hui Bae
- Department of Internal Medicine, Chonnam National University Hospital, Gwangju 61469, Korea.
| |
Collapse
|
11
|
Pedroza L, Soto-Abraham M. Nephropathies with pattern of structural alterations of the glomerular basement membrane: Case study. REVISTA MÉDICA DEL HOSPITAL GENERAL DE MÉXICO 2018. [DOI: 10.1016/j.hgmx.2017.05.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022] Open
|