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Chen X, Hocher CF, Shen L, Krämer BK, Hocher B. Reno- and cardioprotective molecular mechanisms of SGLT2 inhibitors beyond glycemic control: from bedside to bench. Am J Physiol Cell Physiol 2023; 325:C661-C681. [PMID: 37519230 DOI: 10.1152/ajpcell.00177.2023] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2023] [Revised: 07/18/2023] [Accepted: 07/19/2023] [Indexed: 08/01/2023]
Abstract
Large placebo-controlled clinical trials have shown that sodium-glucose cotransporter-2 inhibitors (SGLT2i) delay the deterioration of renal function and reduce cardiovascular events in a glucose-independent manner, thereby ultimately reducing mortality in patients with chronic kidney disease (CKD) and/or heart failure. These existing clinical data stimulated preclinical studies aiming to understand the observed clinical effects. In animal models, it was shown that the beneficial effect of SGLT2i on the tubuloglomerular feedback (TGF) improves glomerular pressure and reduces tubular workload by improving renal hemodynamics, which appears to be dependent on salt intake. High salt intake might blunt the SGLT2i effects on the TGF. Beyond the salt-dependent effects of SGLT2i on renal hemodynamics, SGLT2i inhibited several key aspects of macrophage-mediated renal inflammation and fibrosis, including inhibiting the differentiation of monocytes to macrophages, promoting the polarization of macrophages from a proinflammatory M1 phenotype to an anti-inflammatory M2 phenotype, and suppressing the activation of inflammasomes and major proinflammatory factors. As macrophages are also important cells mediating atherosclerosis and myocardial remodeling after injury, the inhibitory effects of SGLT2i on macrophage differentiation and inflammatory responses may also play a role in stabilizing atherosclerotic plaques and ameliorating myocardial inflammation and fibrosis. Recent studies suggest that SGLT2i may also act directly on the Na+/H+ exchanger and Late-INa in cardiomyocytes thus reducing Na+ and Ca2+ overload-mediated myocardial damage. In addition, the renal-cardioprotective mechanisms of SGLT2i include systemic effects on the sympathetic nervous system, blood volume, salt excretion, and energy metabolism.
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Affiliation(s)
- Xin Chen
- Department of Nephrology, Charité-Universitätsmedizin Berlin, Berlin, Germany
- Fifth Department of Medicine (Nephrology/Endocrinology/Rheumatology/Pneumology), University Medical Centre Mannheim, University of Heidelberg, Heidelberg, Germany
| | - Carl-Friedrich Hocher
- Fifth Department of Medicine (Nephrology/Endocrinology/Rheumatology/Pneumology), University Medical Centre Mannheim, University of Heidelberg, Heidelberg, Germany
- Klinik für Innere Medizin, Bundeswehrkrankenhaus Berlin, Berlin, Germany
| | - Linghong Shen
- Department of Cardiology, Shanghai Chest Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Bernhard K Krämer
- Fifth Department of Medicine (Nephrology/Endocrinology/Rheumatology/Pneumology), University Medical Centre Mannheim, University of Heidelberg, Heidelberg, Germany
| | - Berthold Hocher
- Fifth Department of Medicine (Nephrology/Endocrinology/Rheumatology/Pneumology), University Medical Centre Mannheim, University of Heidelberg, Heidelberg, Germany
- Reproductive and Genetic Hospital of CITIC-Xiangya, Changsha, China
- Institute of Reproductive and Stem Cell Engineering, NHC Key Laboratory of Human Stem Cell and Reproductive Engineering, School of Basic Medical Science, Central South University, Changsha, China
- IMD Institut für Medizinische Diagnostik Berlin-Potsdam GbR, Berlin, Germany
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Sharma S, Smyth B. From Proteinuria to Fibrosis: An Update on Pathophysiology and Treatment Options. Kidney Blood Press Res 2021; 46:411-420. [PMID: 34130301 DOI: 10.1159/000516911] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2020] [Accepted: 04/28/2021] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND Proteinuria is a key biomarker in nephrology. It is central to diagnosis and risk assessment and the primary target of many important therapies. Etiologies resulting in pathological proteinuria include congenital and acquired disorders, as well as both glomerular (immune/non-immune mediated) and tubular defects. SUMMARY Untreated proteinuria is strongly linked to progressive loss of kidney function and kidney failure. Excess protein reaching the renal tubules is ordinarily resorbed by the tubular epithelium. However, when these mechanisms are overwhelmed, a variety of inflammatory and fibrotic pathways are activated, causing both interstitial fibrosis and glomerulosclerosis. Nevertheless, the specific mechanisms underlying this are complex and remain incompletely understood. Recently, a number of treatments, in addition to angiotensin system blockade, have been shown to effectively slow the progression of proteinuric chronic kidney disease. However, additional therapies are clearly needed. Key message: This review provides an update on the pathophysiology of proteinuria, the pathways leading to fibrosis, and an overview of current and emerging therapies.
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Affiliation(s)
- Sonia Sharma
- Department of Pediatric Nephrology, Fortis Hospital, Shalimar-Bagh, New Delhi, India
| | - Brendan Smyth
- Department of Renal Medicine, St. George Hospital, Sydney, New South Wales, Australia
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de Boer D, Streng AS, van Doorn WPTM, Vroemen WHM, Bekers O, Wodzig WKWH, Mingels AMA. Cardiac Troponin T: The Impact of Posttranslational Modifications on Analytical Immunoreactivity in Blood up to the Excretion in Urine. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2021; 1306:41-59. [PMID: 33959905 DOI: 10.1007/978-3-030-63908-2_4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Cardiac troponin T (cTnT) is a sensitive and specific biomarker for detecting cardiac muscle injury. Its concentration in blood can be significantly elevated outside the normal reference range under several pathophysiological conditions. The classical analytical method in routine clinical analysis to detect cTnT in serum or plasma is a single commercial immunoassay, which is designed to quantify the intact cTnT molecule. The targeted epitopes are located in the central region of the cTnT molecule. However, in blood cTnT exists in different biomolecular complexes and proteoforms: bound (to cardiac troponin subunits or to immunoglobulins) or unbound (as intact protein or as proteolytic proteoforms). While proteolysis is a principal posttranslational modification (PTM), other confirmed PTMs of the proteoforms include N-terminal initiator methionine removal, N-acetylation, O-phosphorylation, O-(N-acetyl)-glucosaminylation, N(ɛ)-(carboxymethyl)lysine modification and citrullination. The immunoassay probably detects several of those cTnT biomolecular complexes and proteoforms, as long as they have the centrally targeted epitopes in common. While analytical cTnT immunoreactivity has been studied predominantly in blood, it can also be detected in urine, although it is unclear in which proteoform cTnT immunoreactivity is present in urine. This review presents an overview of the current knowledge on the pathophysiological lifecycle of cTnT. It provides insight into the impact of PTMs, not only on the analytical immunoreactivity, but also on the excretion of cTnT in urine as one of the waste routes in that lifecycle. Accordingly, and after isolating the proteoforms from urine of patients suffering from proteinuria and acute myocardial infarction, the structures of some possible cTnT proteoforms are reconstructed using mass spectrometry and presented.
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Affiliation(s)
- Douwe de Boer
- Unit of Clinical Chemistry, Central Diagnostic Laboratory, Maastricht University Medical Center, Maastricht, The Netherlands.
- NUTRIM, School of Nutrition and Translational Research in Metabolism, Medicine and Life Sciences (FHML) of Maastricht University (UM), Maastricht University Medical Center, Maastricht, The Netherlands.
| | - Alexander S Streng
- Unit of Clinical Chemistry, Central Diagnostic Laboratory, Maastricht University Medical Center, Maastricht, The Netherlands
| | - William P T M van Doorn
- Unit of Clinical Chemistry, Central Diagnostic Laboratory, Maastricht University Medical Center, Maastricht, The Netherlands
| | - Wim H M Vroemen
- Unit of Clinical Chemistry, Central Diagnostic Laboratory, Maastricht University Medical Center, Maastricht, The Netherlands
| | - Otto Bekers
- Unit of Clinical Chemistry, Central Diagnostic Laboratory, Maastricht University Medical Center, Maastricht, The Netherlands
- CARIM, School for Cardiovascular Diseases, Faculty of Health, Medicine and Life Sciences (FHML) of Maastricht University (UM), Maastricht University Medical Center, Maastricht, The Netherlands
| | - Will K W H Wodzig
- Unit of Clinical Chemistry, Central Diagnostic Laboratory, Maastricht University Medical Center, Maastricht, The Netherlands
- NUTRIM, School of Nutrition and Translational Research in Metabolism, Medicine and Life Sciences (FHML) of Maastricht University (UM), Maastricht University Medical Center, Maastricht, The Netherlands
| | - Alma M A Mingels
- Unit of Clinical Chemistry, Central Diagnostic Laboratory, Maastricht University Medical Center, Maastricht, The Netherlands
- CARIM, School for Cardiovascular Diseases, Faculty of Health, Medicine and Life Sciences (FHML) of Maastricht University (UM), Maastricht University Medical Center, Maastricht, The Netherlands
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Moeller MJ, Chia-Gil A. A step forward in understanding glomerular filtration. Nat Rev Nephrol 2020; 16:431-432. [PMID: 32601383 DOI: 10.1038/s41581-020-0313-6] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Marcus J Moeller
- Department of Nephrology and Clinical Immunology, RWTH Aachen University Clinic, Aachen, Germany.
| | - Arnaldo Chia-Gil
- Department of Nephrology and Clinical Immunology, RWTH Aachen University Clinic, Aachen, Germany
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Kuppe C, Rohlfs W, Grepl M, Schulte K, Veron D, Elger M, Sanden SK, Saritas T, Andrae J, Betsholtz C, Trautwein C, Hausmann R, Quaggin S, Bachmann S, Kriz W, Tufro A, Floege J, Moeller MJ. Inverse correlation between vascular endothelial growth factor back-filtration and capillary filtration pressures. Nephrol Dial Transplant 2019; 33:1514-1525. [PMID: 29635428 DOI: 10.1093/ndt/gfy057] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2017] [Accepted: 02/08/2018] [Indexed: 12/17/2022] Open
Abstract
Background Vascular endothelial growth factor A (VEGF) is an essential growth factor during glomerular development and postnatal homeostasis. VEGF is secreted in high amounts by podocytes into the primary urine, back-filtered across the glomerular capillary wall to act on endothelial cells. So far it has been assumed that VEGF back-filtration is driven at a constant rate exclusively by diffusion. Methods In the present work, glomerular VEGF back-filtration was investigated in vivo using a novel extended model based on endothelial fenestrations as surrogate marker for local VEGF concentrations. Single nephron glomerular filtration rate (SNGFR) and/or local filtration flux were manipulated by partial renal mass ablation, tubular ablation, and in transgenic mouse models of systemic or podocytic VEGF overexpression or reduction. Results Our study shows positive correlations between VEGF back-filtration and SNGFR as well as effective filtration rate under physiological conditions along individual glomerular capillaries in rodents and humans. Conclusion Our results suggest that an additional force drives VEGF back-filtration, potentially regulated by SNGFR.
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Affiliation(s)
- Christoph Kuppe
- Division of Nephrology and Immunology, RWTH Aachen University, Aachen, Germany
| | - Wilko Rohlfs
- Institute of Heat and Mass Transfer, RWTH Aachen University, Aachen, Germany
| | - Martin Grepl
- Numerical Mathematics, Faculty for Mathematics, Informatics and Natural Sciences, RWTH Aachen University, Aachen, Germany
| | - Kevin Schulte
- Division of Nephrology and Immunology, RWTH Aachen University, Aachen, Germany.,Department of Nephrology, University of Kiel, Kiel, Germany
| | - Delma Veron
- Department of Pediatrics, Yale University School of Medicine, New Haven, CT, USA
| | - Marlies Elger
- Department of Anatomy and Developmental Biology, Medical Faculty Mannheim, University of Heidelberg, Mannheim, Germany
| | | | - Turgay Saritas
- Division of Nephrology and Immunology, RWTH Aachen University, Aachen, Germany
| | - Johanna Andrae
- Department of Immunology, Genetics and Pathology, Uppsala University, Rudbeck Laboratory, Uppsala, Sweden
| | - Christer Betsholtz
- Department of Immunology, Genetics and Pathology, Uppsala University, Rudbeck Laboratory, Uppsala, Sweden
| | - Christian Trautwein
- Division of Gastroenterology and Endocrinology, RWTH Aachen University Hospital, Aachen, Germany
| | - Ralf Hausmann
- Institute of Molecular Pharmacology, RWTH Aachen University Hospital, Aachen, Germany
| | - Susan Quaggin
- Division of Medicine-Nephrology, Feinberg Cardiovascular Research Institute, Northwestern University Feinberg School of Medicine, Chicago, IL, USA
| | | | - Wilhelm Kriz
- Department of Anatomy and Developmental Biology, Medical Faculty Mannheim, University of Heidelberg, Mannheim, Germany
| | - Alda Tufro
- Department of Pediatrics, Yale University School of Medicine, New Haven, CT, USA
| | - Jürgen Floege
- Division of Nephrology and Immunology, RWTH Aachen University, Aachen, Germany
| | - Marcus J Moeller
- Division of Nephrology and Immunology, RWTH Aachen University, Aachen, Germany.,Interdisciplinary Centre for Clinical Research (IZKF Aachen), RWTH Aachen University Hospital, Aachen, Germany.,Heisenberg Chair for Preventive and Translational Nephrology, Division of Nephrology, RWTH Aachen University, Aachen, Germany
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Barreiro K, Holthofer H. Urinary extracellular vesicles. A promising shortcut to novel biomarker discoveries. Cell Tissue Res 2017; 369:217-227. [PMID: 28429073 PMCID: PMC5487850 DOI: 10.1007/s00441-017-2621-0] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2017] [Accepted: 03/30/2017] [Indexed: 12/13/2022]
Abstract
Proteomic and genomic techniques have reached full maturity and are providing unforeseen details for the comprehensive understanding of disease pathologies at a fraction of previous costs. However, for kidney diseases, many gaps in such information remain to inhibit major advances in the prevention, treatment and diagnostics of these devastating diseases, which have enormous global impact. The discovery of ubiquitous extracellular vesicles (EV) in all bodily fluids is rapidly increasing the fundamental knowledge of disease mechanisms and the ways in which cells communicate with distant locations in processes of cancer spread, immunological regulation, barrier functions and general modulation of cellular activity. In this review, we describe some of the most prominent research streams and findings utilizing urinary extracellular vesicles as highly versatile and dynamic tools with their extraordinary protein and small regulatory RNA species. While being a highly promising approach, the relatively young field of EV research suffers from a lack of adherence to strict standardization and carefully scrutinized methods for obtaining fully reproducible results. With the appropriate guidelines and standardization achieved, urine is foreseen as forming a unique, robust and easy route for determining accurate and personalized disease signatures and as providing highly useful early biomarkers of the disease pathology of the kidney and beyond.
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Affiliation(s)
- Karina Barreiro
- Institute for Molecular Medicine Finland (FIMM), University of Helsinki, Helsinki, Finland
| | - Harry Holthofer
- Institute for Molecular Medicine Finland (FIMM), University of Helsinki, Helsinki, Finland. .,Freiburg Institute for Advanced Studies, Albert-Ludwigs University Freiburg, Freiburg, Germany.
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Buyong MR, Larki F, Takamura Y, Aziz NA, Yunas J, Hamzah AA, Majlis BY. Implementing the concept of dielectrophoresis in glomerular filtration of human kidneys. 2016 IEEE INTERNATIONAL CONFERENCE ON SEMICONDUCTOR ELECTRONICS (ICSE) 2016. [DOI: 10.1109/smelec.2016.7573584] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/02/2023]
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8
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Thomas S, Hao L, Ricke WA, Li L. Biomarker discovery in mass spectrometry-based urinary proteomics. Proteomics Clin Appl 2016; 10:358-70. [PMID: 26703953 DOI: 10.1002/prca.201500102] [Citation(s) in RCA: 101] [Impact Index Per Article: 12.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2015] [Revised: 12/05/2015] [Accepted: 12/21/2015] [Indexed: 01/03/2023]
Abstract
Urinary proteomics has become one of the most attractive topics in disease biomarker discovery. MS-based proteomic analysis has advanced continuously and emerged as a prominent tool in the field of clinical bioanalysis. However, only few protein biomarkers have made their way to validation and clinical practice. Biomarker discovery is challenged by many clinical and analytical factors including, but not limited to, the complexity of urine and the wide dynamic range of endogenous proteins in the sample. This article highlights promising technologies and strategies in the MS-based biomarker discovery process, including study design, sample preparation, protein quantification, instrumental platforms, and bioinformatics. Different proteomics approaches are discussed, and progresses in maximizing urinary proteome coverage and standardization are emphasized in this review. MS-based urinary proteomics has great potential in the development of noninvasive diagnostic assays in the future, which will require collaborative efforts between analytical scientists, systems biologists, and clinicians.
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Affiliation(s)
- Samuel Thomas
- Molecular and Environmental Toxicology Center, University of Wisconsin-Madison, Madison, WI, USA
| | - Ling Hao
- School of Pharmacy, University of Wisconsin-Madison, Madison, WI, USA
| | - William A Ricke
- Molecular and Environmental Toxicology Center, University of Wisconsin-Madison, Madison, WI, USA.,Department of Urology, University of Wisconsin-Madison, Madison, WI, USA
| | - Lingjun Li
- Molecular and Environmental Toxicology Center, University of Wisconsin-Madison, Madison, WI, USA.,School of Pharmacy, University of Wisconsin-Madison, Madison, WI, USA.,Department of Chemistry, University of Wisconsin-Madison, Madison, WI, USA
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