1
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Lopes M, Pires RF, Faria M, Bonifácio VDB. A Novel Strategy for Enhanced Sequestration of Protein-Bound Uremic Toxins Using Smart Hybrid Membranes. J Funct Biomater 2023; 14:jfb14030138. [PMID: 36976062 PMCID: PMC10059720 DOI: 10.3390/jfb14030138] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2022] [Revised: 01/23/2023] [Accepted: 02/24/2023] [Indexed: 03/05/2023] Open
Abstract
Currently available hemodialysis (HD) membranes are unable to safely remove protein-bound uremic toxins (PBUTs), especially those bonded to human serum albumin (HSA). To overcome this issue, the prior administration of high doses of HSA competitive binders, such as ibuprofen (IBF), has been proposed as a complementary clinical protocol to increase HD efficiency. In this work, we designed and prepared novel hybrid membranes conjugated with IBF, thus avoiding its administration to end-stage renal disease (ESRD) patients. Two novel silicon precursors containing IBF were synthesized and, by the combination of a sol-gel reaction and the phase inversion technique, four monophasic hybrid integral asymmetric cellulose acetate/silica/IBF membranes in which silicon precursors are covalently bonded to the cellulose acetate polymer were produced. To prove IBF incorporation, methyl red dye was used as a model, thus allowing simple visual color control of the membrane fabrication and stability. These smart membranes may display a competitive behavior towards HSA, allowing the local displacement of PBUTs in future hemodialyzers.
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Affiliation(s)
- Madalena Lopes
- Center of Physics and Engineering of Advanced Materials CeFEMA, Instituto Superior Técnico, Universidade de Lisboa, 1049-001 Lisboa, Portugal
| | - Rita F. Pires
- Center of Physics and Engineering of Advanced Materials CeFEMA, Instituto Superior Técnico, Universidade de Lisboa, 1049-001 Lisboa, Portugal
| | - Mónica Faria
- Center of Physics and Engineering of Advanced Materials CeFEMA, Instituto Superior Técnico, Universidade de Lisboa, 1049-001 Lisboa, Portugal
- Correspondence: (M.F.); (V.D.B.B.)
| | - Vasco D. B. Bonifácio
- Institute of Bioengineering and Biosciences (iBB) and Institute for Health and Bioeconomy (i4HB), Instituto Superior Técnico, Universidade de Lisboa, 1049-001 Lisboa, Portugal
- Bioengineering Department, Instituto Superior Técnico, Universidade de Lisboa, 1049-001 Lisboa, Portugal
- Correspondence: (M.F.); (V.D.B.B.)
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2
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Lee S, Sirich TL, Meyer TW. Improving Clearance for Renal Replacement Therapy. KIDNEY360 2021; 2:1188-1195. [PMID: 35355887 PMCID: PMC8786098 DOI: 10.34067/kid.0002922021] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
The adequacy of hemodialysis is now assessed by measuring the removal of a single solute, urea. The urea clearance provided by current dialysis methods is a large fraction of the blood flow through the dialyzer, and, therefore, cannot be increased much further. However, other solutes, which are less effectively cleared than urea, may contribute more to the residual uremic illness suffered by patients on hemodialysis. Here, we review a variety of methods that could be used to increase the clearance of such nonurea solutes. New clinical studies will be required to test the extent to which increasing solute clearances improves patients' health.
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Affiliation(s)
- Seolhyun Lee
- Department of Medicine, Stanford University, Palo Alto, California,Department of Medicine, Veterans Affairs Palo Alto Healthcare System, Palo Alto, California
| | - Tammy L. Sirich
- Department of Medicine, Stanford University, Palo Alto, California,Department of Medicine, Veterans Affairs Palo Alto Healthcare System, Palo Alto, California
| | - Timothy W. Meyer
- Department of Medicine, Stanford University, Palo Alto, California,Department of Medicine, Veterans Affairs Palo Alto Healthcare System, Palo Alto, California
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3
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Challenges of reducing protein-bound uremic toxin levels in chronic kidney disease and end stage renal disease. Transl Res 2021; 229:115-134. [PMID: 32891787 DOI: 10.1016/j.trsl.2020.09.001] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/03/2020] [Revised: 08/24/2020] [Accepted: 09/02/2020] [Indexed: 12/11/2022]
Abstract
The prevalence of chronic kidney disease (CKD) in the worldwide population is currently estimated between 11% and 13%. Adequate renal clearance is compromised in these patients and the accumulation of a large number of uremic retention solutes results in an irreversible worsening of renal function which can lead to end stage renal disease (ESRD). Approximately three million ESRD patients currently receive renal replacement therapies (RRTs), such as hemodialysis, which only partially restore kidney function, as they are only efficient in removing mainly small, unbound solutes from the circulation while leaving larger and protein-bound uremic toxins (PBUTs) untouched. The accumulation of PBUTs in patients highly increases the risk of cardiovascular events and is associated with higher mortality and morbidity in CKD and ESRD. In this review, we address several strategies currently being explored toward reducing PBUT concentrations, including clinical and medical approaches, therapeutic techniques, and recent developments in RRT technology. These include preservation of renal function, limitation of colon derived PBUTs, oral sorbents, adsorbent RRT technology, and use of albumin displacers. Despite the promising results of the different approaches to promote enhanced removal of a small percentage of the more than 30 identified PBUTs, on their own, none of them provide a treatment with the required efficiency, safety and cost-effectiveness to prevent CKD-related complications and decrease mortality and morbidity in ESRD.
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4
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Vanholder R, Rondeau E, Anders HJ, Carlson N, Fliser D, Kanbay M, António Lopes J, Murray PT, Ortiz A, Sanz AB, Selby NM, Wiecek A, Massy ZA. EDTAKI: A Nephrology and Public Policy Committee (NPPC) Platform Call for More European Involvement in AKI. Nephrol Dial Transplant 2021; 37:740-748. [PMID: 33527142 DOI: 10.1093/ndt/gfab018] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2020] [Indexed: 01/08/2023] Open
Abstract
Acute Kidney Injury (AKI) is an often neglected but crucial element of clinical nephrology. The aim of the Nephrology Public Policy Committee (NPPC) of the European Renal Association - European Dialysis and Transplant Association (ERA-EDTA) is to promote several key aspects of European nephrology. One of the targets proposed by NPPC was to advance European nephrology involvement in AKI. We undertook literature analyses to define the current position of European nephrology in the field of AKI compared to other regions, and about how different European countries compare to each other. It appeared that vis-à-vis countries with a comparable socio-economic status (the US, Australia, New Zealand, Canada), the European contribution was almost 50% lower. Within Europe, Central/Eastern Europe and countries with a lower gross domestic product (GDP) showed lower scientific output. Nephrologists contributed to less than half of the output. There was no trend for a change over the last decade. It is concluded that there is room to improve the contribution of European nephrology in the field of AKI. We propose a model on how to promote clinical collaboration on AKI across Europe, the creation of a pan-European nephrology network of interested units is proposed, to improve clinical outcomes, increase nephrologist involvement and awareness outside nephrology, and stimulate research on AKI in Europe. Accordingly, we also propose a list of research priorities and stress the need for more European funding of AKI research.
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Affiliation(s)
- Raymond Vanholder
- Nephrology Section, Department of Internal Medicine and Pediatrics, Ghent University Hospital, Ghent, Belgium; European Kidney Health Alliance (EKHA), Brussels, Belgium
| | - Eric Rondeau
- Renal Intensive Care and Transplantation Unit, Hôpital TENON, APHP, Paris; Sorbonne Université, Paris, France
| | - Hans-Joachim Anders
- Division of Nephrology, Department of Medicine IV, University Hospital LMU Munich, Munich, Germany
| | - Nicholas Carlson
- Department of Nephrology, Copenhagen University Hospital Rigshospitalet, Denmark, and Department of Research, The Danish Heart Foundation
| | - Danilo Fliser
- Internal Medicine IV, Saarland University Medical Center, Homburg/Saar, Germany
| | - Mehmet Kanbay
- Nephrology Section, Department of Internal Medicine, Koc University School of Medicine, Istanbul, Turkey
| | - José António Lopes
- Division of Nephrology and Renal Transplantation, Centro Hospitalar Universitário Lisboa Norte, Av. Prof. Egas Moniz, 1649-035, Lisboa, Portugal
| | - Patrick T Murray
- School of Medicine, University College Dublin, UCD Catherine McAuley Education & Research Centre, Eccles Street, Dublin 7, Ireland
| | - Alberto Ortiz
- Research Institute Fundacion Jemenez Diaz, Autonoma University Madrid, Spain
| | - Ana B Sanz
- Research Institute Fundacion Jemenez Diaz, Autonoma University Madrid, Spain
| | - Nicholas M Selby
- Centre for Kidney Research and Innovation, Division of Health Sciences and Graduate Entry Medicine, University of Nottingham, UK
| | - Andrzej Wiecek
- Department of Nephrology, Transplantation and Internal Medicine, Medical University of Silesia in Katowice, Poland
| | - Ziad A Massy
- Department of Nephrology, Ambroise Paré University Hospital, APHP, Boulogne-Billancourt/Paris, and Centre for Research in Epidemiology and Population Health (CESP), Paris-Saclay University, Versailles Saint Quentin University, INSERM UMRS 1018, Team5 Villejuif, France
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5
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Yaker L, Kamel S, Ausseil J, Boullier A. Effects of Chronic Kidney Disease and Uremic Toxins on Extracellular Vesicle Biology. Toxins (Basel) 2020; 12:toxins12120811. [PMID: 33371311 PMCID: PMC7767379 DOI: 10.3390/toxins12120811] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2020] [Revised: 12/02/2020] [Accepted: 12/16/2020] [Indexed: 12/28/2022] Open
Abstract
Vascular calcification (VC) is a cardiovascular complication associated with a high mortality rate, especially in patients with diabetes, atherosclerosis or chronic kidney disease (CKD). In CKD patients, VC is associated with the accumulation of uremic toxins, such as indoxyl sulphate or inorganic phosphate, which can have a major impact in vascular remodeling. During VC, vascular smooth muscle cells (VSMCs) undergo an osteogenic switch and secrete extracellular vesicles (EVs) that are heterogeneous in terms of their origin and composition. Under physiological conditions, EVs are involved in cell-cell communication and the maintenance of cellular homeostasis. They contain high levels of calcification inhibitors, such as fetuin-A and matrix Gla protein. Under pathological conditions (and particularly in the presence of uremic toxins), the secreted EVs acquire a pro-calcifying profile and thereby act as nucleating foci for the crystallization of hydroxyapatite and the propagation of calcification. Here, we review the most recent findings on the EVs’ pathophysiological role in VC, the impact of uremic toxins on EV biogenesis and functions, the use of EVs as diagnostic biomarkers and the EVs’ therapeutic potential in CKD.
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Affiliation(s)
- Linda Yaker
- MP3CV-UR7517, CURS-Université de Picardie Jules Verne, Avenue de la Croix Jourdain, F-80054 Amiens, France; (L.Y.); (S.K.)
| | - Saïd Kamel
- MP3CV-UR7517, CURS-Université de Picardie Jules Verne, Avenue de la Croix Jourdain, F-80054 Amiens, France; (L.Y.); (S.K.)
- Laboratoire de Biochimie CHU Amiens-Picardie, Avenue de la Croix Jourdain, F-80054 Amiens, France
| | - Jérôme Ausseil
- INSERM UMR1043, CNRS UMR5282, University of Toulouse III, F-31024 Toulouse, France;
- CHU PURPAN—Institut Fédératif de Biologie, Laboratoire de Biochimie, Avenue de Grande Bretagne, F-31059 Toulouse, France
| | - Agnès Boullier
- MP3CV-UR7517, CURS-Université de Picardie Jules Verne, Avenue de la Croix Jourdain, F-80054 Amiens, France; (L.Y.); (S.K.)
- Laboratoire de Biochimie CHU Amiens-Picardie, Avenue de la Croix Jourdain, F-80054 Amiens, France
- Correspondence: ; Tel.: +33-322087019
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6
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Sławuta P, Sikorska-Kopyłowicz A, Sapikowski G. Diagnostic utility of different models used to assess the acid-base balance in cats with chronic kidney disease. Acta Vet Hung 2020; 68:169-176. [PMID: 32857709 DOI: 10.1556/004.2020.00032] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2019] [Accepted: 05/06/2020] [Indexed: 11/19/2022]
Abstract
Metabolic acidosis is diagnosed based on the concentration of bicarbonate ions and partial pressure of carbon dioxide in arterial blood, although acid-base balance (ABB) disorders may also be diagnosed based on the serum ion concentrations in order to determine the values of strong ion difference (SID), anion gap (AG), corrected anion gap (AGcorr) and chloride/sodium ratio (Cl-/Na+). The aim of this study was to assess and compare the classic model, the value of the AG, AGcorr, and Cl-/Na+ in the diagnosis of ABB disorders in cats with chronic kidney disease (CKD). The study group consisted of 80 cats with CKD, divided into four groups based on the guidelines of the International Renal Interest Society (IRIS). The control group (C) included 20 healthy cats. Metabolic acidosis - diagnosed based on the classic model (Hendersson-Hasselbalch equation) - was found in IRIS group IV. AG, AGcorr, SID calculated for IRIS groups II, III and IV were lower than in group C, while the value of AGdiff and Cl-/Na+ in those groups was higher than in group C. We can conclude that ABB analysis using the classic model enabled the detection of ABB disorders in cats in stage IV CKD. However, the analysis of the AG, AGcorr and Cl-/Na+ values enabled the diagnosis of acid-base balance disorders in cats with IRIS stage II, III and IV CKD.
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Affiliation(s)
- Piotr Sławuta
- Department of Internal Medicine and Clinic of Diseases of Horses, Dogs and Cats, The Faculty of Veterinary Medicine, Wrocław University of Environmental and Life Science, Norwida 32, 50-375, Wrocław, Poland
| | - Agnieszka Sikorska-Kopyłowicz
- Department of Internal Medicine and Clinic of Diseases of Horses, Dogs and Cats, The Faculty of Veterinary Medicine, Wrocław University of Environmental and Life Science, Norwida 32, 50-375, Wrocław, Poland
| | - Grzegorz Sapikowski
- Department of Internal Medicine and Clinic of Diseases of Horses, Dogs and Cats, The Faculty of Veterinary Medicine, Wrocław University of Environmental and Life Science, Norwida 32, 50-375, Wrocław, Poland
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7
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Nigam SK, Bush KT. Uraemic syndrome of chronic kidney disease: altered remote sensing and signalling. Nat Rev Nephrol 2019; 15:301-316. [PMID: 30728454 DOI: 10.1038/s41581-019-0111-1] [Citation(s) in RCA: 84] [Impact Index Per Article: 16.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Uraemic syndrome (also known as uremic syndrome) in patients with advanced chronic kidney disease involves the accumulation in plasma of small-molecule uraemic solutes and uraemic toxins (also known as uremic toxins), dysfunction of multiple organs and dysbiosis of the gut microbiota. As such, uraemic syndrome can be viewed as a disease of perturbed inter-organ and inter-organism (host-microbiota) communication. Multiple biological pathways are affected, including those controlled by solute carrier (SLC) and ATP-binding cassette (ABC) transporters and drug-metabolizing enzymes, many of which are also involved in drug absorption, distribution, metabolism and elimination (ADME). The remote sensing and signalling hypothesis identifies SLC and ABC transporter-mediated communication between organs and/or between the host and gut microbiota as key to the homeostasis of metabolites, antioxidants, signalling molecules, microbiota-derived products and dietary components in body tissues and fluid compartments. Thus, this hypothesis provides a useful perspective on the pathobiology of uraemic syndrome. Pathways considered central to drug ADME might be particularly important for the body's attempts to restore homeostasis, including the correction of disturbances due to kidney injury and the accumulation of uraemic solutes and toxins. This Review discusses how the remote sensing and signalling hypothesis helps to provide a systems-level understanding of aspects of uraemia that could lead to novel approaches to its treatment.
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Affiliation(s)
- Sanjay K Nigam
- Department of Pediatrics, University of California San Diego, La Jolla, CA, USA. .,Department of Medicine, University of California San Diego, La Jolla, CA, USA.
| | - Kevin T Bush
- Department of Pediatrics, University of California San Diego, La Jolla, CA, USA
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8
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Noce A, Marrone G, Di Daniele F, Ottaviani E, Wilson Jones G, Bernini R, Romani A, Rovella V. Impact of Gut Microbiota Composition on Onset and Progression of Chronic Non-Communicable Diseases. Nutrients 2019; 11:nu11051073. [PMID: 31091761 PMCID: PMC6567014 DOI: 10.3390/nu11051073] [Citation(s) in RCA: 73] [Impact Index Per Article: 14.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2019] [Revised: 05/07/2019] [Accepted: 05/08/2019] [Indexed: 02/07/2023] Open
Abstract
In recent years, mounting scientific evidence has emerged regarding the evaluation of the putative correlation between the gut microbiota composition and the presence of chronic non-communicable diseases (NCDs), such as diabetes mellitus, chronic kidney disease, and arterial hypertension. The aim of this narrative review is to examine the current literature with respect to the relationship between intestinal dysbiosis and the insurgence/progression of chronic NCDs, analyzing the physiopathological mechanisms that can induce microbiota modification in the course of these pathologies, and the possible effect induced by microbiota alteration upon disease onset. Therapy based on probiotics, prebiotics, synbiotics, postbiotics, and fecal microbiota transplant can represent a useful therapeutic tool, as has been highlighted on animal studies. To this moment, clinical studies that intended to demonstrate the beneficial effect induced by this kind of oral supplementation on the gut microbiota composition, and subsequent amelioration of signs and symptoms of chronic NCDs have been conducted on limited sample populations for a limited follow-up period. Therefore, to fully evaluate the therapeutic value of this kind of intervention, it would be ideal to design ample population; randomized clinical trials with a lengthy follow up period.
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Affiliation(s)
- Annalisa Noce
- UOC of Internal Medicine-Center of Hypertension and Nephrology Unit, Department of Systems Medicine, University of Rome, via Montpellier 1, 00133 Rome, Italy.
| | - Giulia Marrone
- UOC of Internal Medicine-Center of Hypertension and Nephrology Unit, Department of Systems Medicine, University of Rome, via Montpellier 1, 00133 Rome, Italy.
- PhD School of Applied Medical- Surgical Sciences, University of Rome Tor Vergata, Via Montpellier 1, 00133 Rome, Italy.
| | - Francesca Di Daniele
- UOC of Internal Medicine-Center of Hypertension and Nephrology Unit, Department of Systems Medicine, University of Rome, via Montpellier 1, 00133 Rome, Italy.
| | - Eleonora Ottaviani
- UOC of Internal Medicine-Center of Hypertension and Nephrology Unit, Department of Systems Medicine, University of Rome, via Montpellier 1, 00133 Rome, Italy.
| | - Georgia Wilson Jones
- UOC of Internal Medicine-Center of Hypertension and Nephrology Unit, Department of Systems Medicine, University of Rome, via Montpellier 1, 00133 Rome, Italy.
| | - Roberta Bernini
- Department of Agriculture and Forest Sciences (DAFNE), University of Tuscia, 01100 Viterbo, Italy.
| | - Annalisa Romani
- PHYTOLAB-DISIA-Department of Informatics, Statistics and Applications G. Parenti, University of Florence, Viale Morgagni, 59-50134 Florence, Italy and QuMAP-PIN-Piazza Giovanni Ciardi, 25, 59100 Prato (PO), Italy.
| | - Valentina Rovella
- UOC of Internal Medicine-Center of Hypertension and Nephrology Unit, Department of Systems Medicine, University of Rome, via Montpellier 1, 00133 Rome, Italy.
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Chaïbi K, Barbar S, Quenot JP, Dreyfuss D, Gaudry S. Retarder une épuration extrarénale dans l’insuffisance rénale aiguë : la nuit nous appartient. MEDECINE INTENSIVE REANIMATION 2019. [DOI: 10.3166/rea-2018-0081] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Les indications de l’épuration extrarénale (EER) dans le contexte d’insuffisance rénale aiguë en réanimation sont débattues avec une certaine passion. Il est évident que les situations qui peuvent menacer immédiatement le pronostic vital (hyperkaliémie ou acidose métabolique réfractaire et sévère ou oedème pulmonaire de surcharge chez le patient anurique) nécessitent un recours urgent à l’EER. Hormis ces situations extrêmes, des études de haut niveau de preuve ont récemment montré que retarder l’indication de l’EER n’affecte pas la survie des patients et pourrait même favoriser la récupération de la fonction rénale par comparaison à une EER trop précoce. Cette mise au point se propose de discuter les risques théoriques liés au fait de différer l’EER et s’attache à montrer qu’ils constituent plus des craintes que des réalités.
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10
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Kalim S, Wald R, Yan AT, Goldstein MB, Kiaii M, Xu D, Berg AH, Clish C, Thadhani R, Rhee EP, Perl J. Extended Duration Nocturnal Hemodialysis and Changes in Plasma Metabolite Profiles. Clin J Am Soc Nephrol 2018; 13:436-444. [PMID: 29444900 PMCID: PMC5967674 DOI: 10.2215/cjn.08790817] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2017] [Accepted: 12/08/2017] [Indexed: 12/28/2022]
Abstract
BACKGROUND AND OBJECTIVES In-center, extended duration nocturnal hemodialysis has been associated with variable clinical benefits, but the effect of extended duration hemodialysis on many established uremic solutes and other components of the metabolome is unknown. We determined the magnitude of change in metabolite profiles for patients on extended duration nocturnal hemodialysis. DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS In a 52-week prospective, observational study, we followed 33 patients receiving conventional thrice weekly hemodialysis who converted to nocturnal hemodialysis (7-8 hours per session, three times per week). A separate group of 20 patients who remained on conventional hemodialysis (3-4 hours per session, three times per week) served as a control group. For both groups, we applied liquid chromatography-mass spectrometry-based metabolite profiling on stored plasma samples collected from all participants at baseline and after 1 year. We examined longitudinal changes in 164 metabolites among those who remained on conventional hemodialysis and those who converted to nocturnal hemodialysis using Wilcoxon rank sum tests adjusted for multiple comparisons (false discovery rate <0.05). RESULTS On average, the nocturnal group had 9.6 hours more dialysis per week than the conventional group. Among 164 metabolites, none changed significantly from baseline to study end in the conventional group. Twenty-nine metabolites changed in the nocturnal group, 21 of which increased from baseline to study end (including all branched-chain amino acids). Eight metabolites decreased after conversion to nocturnal dialysis, including l-carnitine and acetylcarnitine. By contrast, several established uremic retention solutes, including p-cresol sulfate, indoxyl sulfate, and trimethylamine N-oxide, did not change with extended dialysis. CONCLUSIONS Across a wide array of metabolites examined, extended duration hemodialysis was associated with modest changes in the plasma metabolome, with most differences relating to metabolite increases, despite increased dialysis time. Few metabolites showed reduction with more dialysis, and no change in several established uremic toxins was observed.
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Affiliation(s)
| | | | - Andrew T. Yan
- Cardiology, St. Michael’s Hospital, University of Toronto, Toronto, Ontario, Canada
| | | | - Mercedeh Kiaii
- Division of Nephrology, St. Paul’s Hospital, Vancouver, British Columbia, Canada
| | | | - Anders H. Berg
- Department of Pathology, Beth Israel Deaconess Medical Center, Boston, Massachusetts; and
| | | | | | - Eugene P. Rhee
- Nephrology Division and
- Endocrinology Unit, Massachusetts General Hospital, Boston, Massachusetts
- Broad Institute, Cambridge, Massachusetts
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11
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Argyropoulos CP, Chen SS, Ng YH, Roumelioti ME, Shaffi K, Singh PP, Tzamaloukas AH. Rediscovering Beta-2 Microglobulin As a Biomarker across the Spectrum of Kidney Diseases. Front Med (Lausanne) 2017; 4:73. [PMID: 28664159 PMCID: PMC5471312 DOI: 10.3389/fmed.2017.00073] [Citation(s) in RCA: 150] [Impact Index Per Article: 21.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2017] [Accepted: 05/26/2017] [Indexed: 12/28/2022] Open
Abstract
There is currently an unmet need for better biomarkers across the spectrum of renal diseases. In this paper, we revisit the role of beta-2 microglobulin (β2M) as a biomarker in patients with chronic kidney disease and end-stage renal disease. Prior to reviewing the numerous clinical studies in the area, we describe the basic biology of β2M, focusing in particular on its role in maintaining the serum albumin levels and reclaiming the albumin in tubular fluid through the actions of the neonatal Fc receptor. Disorders of abnormal β2M function arise as a result of altered binding of β2M to its protein cofactors and the clinical manifestations are exemplified by rare human genetic conditions and mice knockouts. We highlight the utility of β2M as a predictor of renal function and clinical outcomes in recent large database studies against predictions made by recently developed whole body population kinetic models. Furthermore, we discuss recent animal data suggesting that contrary to textbook dogma urinary β2M may be a marker for glomerular rather than tubular pathology. We review the existing literature about β2M as a biomarker in patients receiving renal replacement therapy, with particular emphasis on large outcome trials. We note emerging proteomic data suggesting that β2M is a promising marker of chronic allograft nephropathy. Finally, we present data about the role of β2M as a biomarker in a number of non-renal diseases. The goal of this comprehensive review is to direct attention to the multifaceted role of β2M as a biomarker, and its exciting biology in order to propose the next steps required to bring this recently rediscovered biomarker into the twenty-first century.
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Affiliation(s)
- Christos P Argyropoulos
- Nephrology Division, Department of Internal Medicine, University of New Mexico School of Medicine, Albuquerque, NM, United States
| | - Shan Shan Chen
- Nephrology Division, Department of Internal Medicine, University of New Mexico School of Medicine, Albuquerque, NM, United States
| | - Yue-Harn Ng
- Nephrology Division, Department of Internal Medicine, University of New Mexico School of Medicine, Albuquerque, NM, United States
| | - Maria-Eleni Roumelioti
- Nephrology Division, Department of Internal Medicine, University of New Mexico School of Medicine, Albuquerque, NM, United States
| | - Kamran Shaffi
- Nephrology Division, Department of Internal Medicine, University of New Mexico School of Medicine, Albuquerque, NM, United States
| | - Pooja P Singh
- Nephrology Division, Department of Internal Medicine, University of New Mexico School of Medicine, Albuquerque, NM, United States
| | - Antonios H Tzamaloukas
- Nephrology Division, Department of Internal Medicine, University of New Mexico School of Medicine, Albuquerque, NM, United States.,Raymond G. Murphy VA Medical Center Albuquerque, Albuquerque, NM, United States
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12
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Favretto G, Souza LM, Gregório PC, Cunha RS, Maciel RAP, Sassaki GL, Toledo MG, Pecoits-Filho R, Souza WM, Stinghen AEM. Role of Organic Anion Transporters in the Uptake of Protein-Bound Uremic Toxins by Human Endothelial Cells and Monocyte Chemoattractant Protein-1 Expression. J Vasc Res 2017; 54:170-179. [PMID: 28472795 DOI: 10.1159/000468542] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2016] [Accepted: 03/05/2017] [Indexed: 12/12/2022] Open
Abstract
Organic anion transporters (OATs) are involved in the uptake of uremic toxins such as p-cresyl sulfate (PCS) and indoxyl sulfate (IS), which play a role in endothelial dysfunction in patients with chronic kidney diseases (CKD). In this study, we investigated the role of OAT1 and OAT3 in the uptake of PCS and IS into human endothelial cells. PCS was synthesized via p-cresol sulfation and characterized using analytical methods. The cells were treated with PCS and IS in the absence and presence of probenecid (Pb), an OAT inhibitor. Cell viability was assessed using the MTT assay. The absorbed toxins were analyzed using chromatography, OAT expression using immunocytochemistry and western blot, and monocyte chemoattractant protein-1 (MCP-1) expression using enzyme-linked immunosorbent assay. Cell viability decreased after toxin treatment in a dose-dependent manner. PCS and IS showed significant internalization after 60 min treatment, while no internalization was observed in the presence of Pb, suggesting that OATs are involved in the transport of both toxins. Immunocytochemistry and western blot demonstrated OAT1 and OAT3 expression in endothelial cells. MCP-1 expression increased after toxins treatment but decreased after Pb treatment. PCS and IS uptake were mediated by OATs, and OAT blockage could serve as a therapeutic strategy to inhibit MCP-1 expression.
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Affiliation(s)
- Giane Favretto
- Experimental Nephrology Laboratory, Basic Pathology Department, Universidade Federal do Paraná, Curitiba, Brazil
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Roumelioti ME, Nolin T, Unruh ML, Argyropoulos C. Revisiting the Middle Molecule Hypothesis of Uremic Toxicity: A Systematic Review of Beta 2 Microglobulin Population Kinetics and Large Scale Modeling of Hemodialysis Trials In Silico. PLoS One 2016; 11:e0153157. [PMID: 27055286 PMCID: PMC4824495 DOI: 10.1371/journal.pone.0153157] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2015] [Accepted: 03/24/2016] [Indexed: 01/01/2023] Open
Abstract
Background Beta-2 Microglobulin (β2M) is a prototypical “middle molecule” uremic toxin that has been associated with a higher risk of death in hemodialysis patients. A quantitative description of the relative importance of factors determining β2M concentrations among patients with impaired kidney function is currently lacking. Methods Herein we undertook a systematic review of existing studies reporting patient level data concerning generation, elimination and distribution of β2M in order to develop a population model of β2M kinetics. We used this model and previously determined relationships between predialysis β2M concentration and survival, to simulate the population distribution of predialysis β2M and the associated relative risk (RR) of death in patients receiving conventional thrice-weekly hemodialysis with low flux (LF) and high flux (HF) dialyzers, short (SD) and long daily (LD) HF hemodialysis sessions and on-line hemodiafiltration at different levels of residual renal function (RRF). Results We identified 9 studies of 106 individuals and 156 evaluations of or more compartmental kinetic parameters of β2M. These studies used a variety of experimental methods to determine β2M kinetics ranging from isotopic dilution to profiling of intra/inter dialytic concentration changes. Most of the patients (74/106) were on dialysis with minimal RRF, thus facilitating the estimation of non-renal elimination kinetics of β2M. In large scale (N = 10000) simulations of individuals drawn from the population of β2M kinetic parameters, we found that, higher dialytic removal materially affects β2M exposures only when RRF (renal clearance of β2M) was below 2 ml/min. In patients initiating conventional HF hemodialysis, total loss of RRF was predicted to be associated with a RR of death of more than 20%. Hemodiafiltration and daily dialysis may decrease the high risk of death of anuric patients by 10% relative to conventional, thrice weekly HF dialysis. Only daily long sessions of hemodialysis consistently reduced mortality risk between 7–19% across the range of β2M generation rate. Conclusions Preservation of RRF should be considered one of the therapeutic goals of hemodialysis practice. Randomized controlled trials of novel dialysis modalities may require large sample sizes to detect an effect on clinical outcomes even if they enroll anuric patients. The developed population model for β2M may allow personalization of hemodialysis prescription and/or facilitate the design of such studies by identifying patients with higher β2M generation rate.
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Affiliation(s)
- Maria Eleni Roumelioti
- Division of Nephrology, Department of Internal Medicine, University of New Mexico Health Sciences Center, School of Medicine, Albuquerque, NM, United States of America
| | - Thomas Nolin
- Department of Pharmacy and Therapeutics, and Renal-Electrolyte Division, Department of Medicine, University of Pittsburgh Schools of Pharmacy and Medicine, Pittsburgh, PA, United States of America
| | - Mark L. Unruh
- Division of Nephrology, Department of Internal Medicine, University of New Mexico Health Sciences Center, School of Medicine, Albuquerque, NM, United States of America
| | - Christos Argyropoulos
- Division of Nephrology, Department of Internal Medicine, University of New Mexico Health Sciences Center, School of Medicine, Albuquerque, NM, United States of America
- * E-mail:
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Nigam SK, Wu W, Bush KT, Hoenig MP, Blantz RC, Bhatnagar V. Handling of Drugs, Metabolites, and Uremic Toxins by Kidney Proximal Tubule Drug Transporters. Clin J Am Soc Nephrol 2015; 10:2039-49. [PMID: 26490509 DOI: 10.2215/cjn.02440314] [Citation(s) in RCA: 176] [Impact Index Per Article: 19.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2014] [Accepted: 09/28/2014] [Indexed: 01/22/2023]
Abstract
The proximal tubule of the kidney plays a crucial role in the renal handling of drugs (e.g., diuretics), uremic toxins (e.g., indoxyl sulfate), environmental toxins (e.g., mercury, aristolochic acid), metabolites (e.g., uric acid), dietary compounds, and signaling molecules. This process is dependent on many multispecific transporters of the solute carrier (SLC) superfamily, including organic anion transporter (OAT) and organic cation transporter (OCT) subfamilies, and the ATP-binding cassette (ABC) superfamily. We review the basic physiology of these SLC and ABC transporters, many of which are often called drug transporters. With an emphasis on OAT1 (SLC22A6), the closely related OAT3 (SLC22A8), and OCT2 (SLC22A2), we explore the implications of recent in vitro, in vivo, and clinical data pertinent to the kidney. The analysis of murine knockouts has revealed a key role for these transporters in the renal handling not only of drugs and toxins but also of gut microbiome products, as well as liver-derived phase 1 and phase 2 metabolites, including putative uremic toxins (among other molecules of metabolic and clinical importance). Functional activity of these transporters (and polymorphisms affecting it) plays a key role in drug handling and nephrotoxicity. These transporters may also play a role in remote sensing and signaling, as part of a versatile small molecule communication network operative throughout the body in normal and diseased states, such as AKI and CKD.
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Affiliation(s)
- Sanjay K Nigam
- Department of Medicine, Department of Pediatrics, Department of Cell & Molecular Medicine,
| | | | | | - Melanie P Hoenig
- Division of Nephrology, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, Massachusetts
| | - Roland C Blantz
- Division of Nephrology-Hypertension, and Veterans Affairs San Diego Healthcare System, San Diego, California; and
| | - Vibha Bhatnagar
- Division of Family & Preventative Medicine, University of California-San Diego, La Jolla, California
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15
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M'Baya-Moutoula E, Louvet L, Metzinger-Le Meuth V, Massy ZA, Metzinger L. High inorganic phosphate concentration inhibits osteoclastogenesis by modulating miR-223. Biochim Biophys Acta Mol Basis Dis 2015; 1852:2202-12. [PMID: 26255635 DOI: 10.1016/j.bbadis.2015.08.003] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2015] [Revised: 07/21/2015] [Accepted: 08/05/2015] [Indexed: 01/08/2023]
Abstract
Chronic kidney disease-mineral and bone disorder (CKD-MBD) is a common complication of CKD, and uremic toxins have been shown to be instrumental in this process. We have previously shown that miR-223 is increased in smooth muscle cells subjected to the uremic toxin inorganic phosphate (Pi). In the present study we investigated the influence of this miRNA in osteoclastogenesis in order to elucidate its role in the course of CKD-MBD. RT-qPCR demonstrated that high Pi concentration decreased miR-223 expression in differentiated RAW 264.7 cells. Up- and down-regulation of miR-223 was performed using specific pre-miR and anti-miR-223. Differentiation of monocyte/macrophage precursors was assessed by using RAW 264.7 cells and peripheral blood mononuclear cells (PBMC). TRAP activity and bone resorption were used to measure osteoclast activity. Pi induced a marked decrease in osteoclastogenesis in RAW cells and miR-223 levels were concomitantly decreased. Anti-miR-223 treatment inhibited osteoclastogenesis in the same way as Pi. In contrast, overexpression of miR-223 triggered differentiation, as reflected by TRAP activity. We showed that miR-223 affected the expression of its target genes NFIA and RhoB, but also osteoclast marker genes and the Akt signalling pathway, which induces osteoclastogenesis. These results were confirmed by measuring bone resorption activity of human PBMC differentiated into osteoclasts. We thus demonstrate a role of miR-223 in osteoclast differentiation, with rational grounds to use deregulation of this miRNA to selectively increase osteoclast-like activity in calcified vessels of CKD-MBD. This approach could alleviate vascular calcification without altering bone structure.
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Affiliation(s)
| | - Loïc Louvet
- INSERM U1088, CURS, CHU Amiens Sud, Avenue René Laënnec, Salouel, F-80054 Amiens, France
| | - Valérie Metzinger-Le Meuth
- INSERM U1088, CURS, CHU Amiens Sud, Avenue René Laënnec, Salouel, F-80054 Amiens, France; University Paris 13, UFR SMBH, 74 rue Marcel Cachin, F-93017 Bobigny, France
| | - Ziad A Massy
- INSERM U1088, CURS, CHU Amiens Sud, Avenue René Laënnec, Salouel, F-80054 Amiens, France; Division of Nephrology, Ambroise Paré Hospital, Paris Ile de France Ouest (UVSQ) University, 09 Avenue Charles de Gaulle 92100 Boulogne Billancourt Cedex, France
| | - Laurent Metzinger
- INSERM U1088, CURS, CHU Amiens Sud, Avenue René Laënnec, Salouel, F-80054 Amiens, France; Centre De Biologie Humaine (CBH), Amiens University Hospital, F-80054 Amiens, France.
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16
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Kalim S, Clish CB, Deferio JJ, Ortiz G, Moffet AS, Gerszten RE, Thadhani R, Rhee EP. Cross-sectional examination of metabolites and metabolic phenotypes in uremia. BMC Nephrol 2015; 16:98. [PMID: 26149577 PMCID: PMC4491861 DOI: 10.1186/s12882-015-0100-y] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2015] [Accepted: 06/28/2015] [Indexed: 01/21/2023] Open
Abstract
BACKGROUND Although metabolomic approaches have begun to document numerous changes that arise in end stage renal disease (ESRD), how these alterations relate to established metabolic phenotypes in uremia is unknown. METHODS In 200 incident hemodialysis patients we used partial least squares discriminant analysis to identify which among 166 metabolites could best discriminate individuals with or without diabetes, and across tertiles of body mass index, serum albumin, total cholesterol, and systolic blood pressure. RESULTS Our data do not recapitulate metabolomic signatures of diabetes and obesity identified among individuals with normal renal function (e.g. elevations in branched chain and aromatic amino acids) and highlight several potential markers of diabetes status specific to ESRD, including xanthosine-5-phosphate and vanillylmandelic acid. Further, our data identify significant associations between elevated tryptophan and long-chain acylcarnitine levels and both decreased total cholesterol and systolic blood pressure in ESRD. Higher tryptophan levels were also associated with higher serum albumin levels, but this may reflect tryptophan's significant albumin binding. Finally, an examination of the uremic retention solutes captured by our platform in relation to 24 clinical phenotypes provides a framework for investigating mechanisms of uremic toxicity. CONCLUSIONS In sum, these studies leveraging metabolomic and metabolic phenotype data acquired in a well-characterized ESRD cohort demonstrate striking differences from metabolomics studies in the general population, and may provide clues to novel functional pathways in the ESRD population.
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Affiliation(s)
- Sahir Kalim
- Division of Nephrology, Massachusetts General Hospital (MGH), 165 Cambridge Street, Suite 302, Boston, MA, 02114, USA.
| | | | - Joseph J Deferio
- Division of Nephrology, Massachusetts General Hospital (MGH), 165 Cambridge Street, Suite 302, Boston, MA, 02114, USA.
| | - Guillermo Ortiz
- Division of Nephrology, Massachusetts General Hospital (MGH), 165 Cambridge Street, Suite 302, Boston, MA, 02114, USA.
| | - Alexander S Moffet
- Division of Nephrology, Massachusetts General Hospital (MGH), 165 Cambridge Street, Suite 302, Boston, MA, 02114, USA.
| | - Robert E Gerszten
- Broad Institute, Cambridge, MA, USA. .,Cardiology Division, MGH, Boston, MA, USA. .,Cardiovascular Research Center, MGH, Boston, MA, USA.
| | - Ravi Thadhani
- Division of Nephrology, Massachusetts General Hospital (MGH), 165 Cambridge Street, Suite 302, Boston, MA, 02114, USA.
| | - Eugene P Rhee
- Division of Nephrology, Massachusetts General Hospital (MGH), 165 Cambridge Street, Suite 302, Boston, MA, 02114, USA. .,Broad Institute, Cambridge, MA, USA.
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Schneider SM, Kielstein JT, Braverman J, Novak M. Cognitive Function in Patients With Chronic Kidney Disease: Challenges in Neuropsychological Assessments. Semin Nephrol 2015; 35:304-10. [DOI: 10.1016/j.semnephrol.2015.06.002] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
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19
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Kalim S, Clish CB, Wenger J, Elmariah S, Yeh RW, Deferio JJ, Pierce K, Deik A, Gerszten RE, Thadhani R, Rhee EP. A plasma long-chain acylcarnitine predicts cardiovascular mortality in incident dialysis patients. J Am Heart Assoc 2013; 2:e000542. [PMID: 24308938 PMCID: PMC3886735 DOI: 10.1161/jaha.113.000542] [Citation(s) in RCA: 90] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Background The marked excess in cardiovascular mortality that results from uremia remains poorly understood. Methods and Results In 2 independent, nested case‐control studies, we applied liquid chromatography‐mass spectrometry‐based metabolite profiling to plasma obtained from participants of a large cohort of incident hemodialysis patients. First, 100 individuals who died of a cardiovascular cause within 1 year of initiating hemodialysis (cases) were randomly selected along with 100 individuals who survived for at least 1 year (controls), matched for age, sex, and race. Four highly intercorrelated long‐chain acylcarnitines achieved the significance threshold adjusted for multiple testing (P<0.0003). Oleoylcarnitine, the long‐chain acylcarnitine with the strongest association with cardiovascular mortality in unadjusted analysis, remained associated with 1‐year cardiovascular death after multivariable adjustment (odds ratio per SD 2.3 [95% confidence interval, 1.4 to 3.8]; P=0.001). The association between oleoylcarnitine and 1‐year cardiovascular death was then replicated in an independent sample (n=300, odds ratio per SD 1.4 [95% confidence interval, 1.1 to 1.9]; P=0.008). Addition of oleoylcarnitine to clinical variables improved cardiovascular risk prediction using net reclassification (NRI, 0.38 [95% confidence interval, 0.20 to 0.56]; P<0.0001). In physiologic profiling studies, we demonstrate that the fold change in plasma acylcarnitine levels from the aorta to renal vein and from pre‐ to post hemodialysis samples exclude renal or dialytic clearance of long‐chain acylcarnitines as confounders in our analysis. Conclusions Our data highlight clinically meaningful alterations in acylcarnitine homeostasis at the time of dialysis initiation, which may represent an early marker, effector, or both of uremic cardiovascular risk.
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Affiliation(s)
- Sahir Kalim
- Cardiovascular Research Center, Massachusetts General Hospital, Boston, MA
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20
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Numerous protein-bound solutes are cleared by the kidney with high efficiency. Kidney Int 2013; 84:585-90. [PMID: 23636170 PMCID: PMC3758437 DOI: 10.1038/ki.2013.154] [Citation(s) in RCA: 101] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2012] [Revised: 02/18/2013] [Accepted: 02/21/2013] [Indexed: 11/21/2022]
Abstract
The kidney clears numerous solutes from the plasma; however, retention of these solutes
causes uremic illness when the kidneys fail. We know remarkably little about which retained solutes
are toxic and this limits our ability to improve dialysis therapies. To explore this we employed
untargeted mass spectrometry to identify solutes that are efficiently cleared by the kidney. High
resolution mass spectrometry detected 1808 features in the urine and plasma ultrafiltrate of 5
individuals with normal renal function. The estimated clearance rates of 1082 peaks were greater
than the creatinine clearance indicating tubular secretion. Further analysis identified 90 features
representing solutes with estimated clearance rates greater than the renal plasma flow. Quantitative
mass spectrometry with stable isotope dilution confirmed that efficient clearance of these solutes
is made possible by the combination of binding to plasma proteins and tubular secretion. Tandem mass
spectrometry established the chemical identity of 13 solutes including hippuric acid, indoxyl
sulfate, and p-cresol sulfate. These 13 efficiently cleared solutes were found to accumulate in the
plasma of hemodialysis patients, with free levels rising to more than 20-fold normal for all but two
of them. Thus, further analysis of solutes efficiently cleared by secretion in the native kidney may
provide a potential route to the identification of uremic toxins.
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21
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Kielstein JT, Suntharalingam M, Perthel R, Rong S, Martens-Lobenhoffer J, Jäger K, Bode-Böger SM, Nave H. Asymmetric dimethylarginine may mediate increased heat pain threshold in experimental chronic kidney disease. Nephrol Dial Transplant 2011; 27:899-902. [PMID: 22131232 DOI: 10.1093/ndt/gfr629] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
BACKGROUND Thermal sensitivity in uraemia is decreased. Non-selective synthetic nitric oxide synthase (NOS) inhibitors significantly attenuate thermal hyperalgesia in preclinical models. The aim of our study was to evaluate the effect of experimental uraemia, which is associated with an increase of the endogenous NOS inhibitor asymmetric dimethylarginine (ADMA), on thermal sensitivity in rats. Furthermore, we intended to study the effect of chronic ADMA infusion alone on thermal sensitivity. METHODS Male Sprague-Dawley rats (n = 54), 10 weeks old, weight 370-430 g, were randomly assigned to three groups receiving either (i) isotonic saline or (ii) ADMA via osmotic mini pumps or (iii) underwent 5/6 nephrectomy (Nx). After 14 days, 50% of all animals from all groups underwent thermal sensitivity testing and terminal blood draw. After 28 days, the remaining animals underwent the same procedures. Thermal sensitivity examination was performed by the hot-plate test, measuring time from heat exposition to first paw licking or jumping of the animal. RESULTS While the median [interquartile range] latency time between heat exposition to first paw licking or jumping of the animal in the NaCl infusion group remained unchanged between Day 14 (8.4 [6.75-11.50] s) and Day 28 (7.35 [6.10-7.90] s) both, ADMA infusion and 5/6 nephrectomy tended to increase the thermal pain threshold at Day 14 (9.25 [6.55-12.18] s) and (9.50 [5.8 ± 11.0] s), respectively, compared to NaCl on Day 14 (8.4 [6.75-11.50] s). This difference became statistical significant at Day 28 where the median latency time in the ADMA group (13.10 [11.85-15.95] s) and in the 5/6 Nx group (13.50 [10.85-17.55] s) were significantly higher than in the NaCl group (7.35 [6.10-7.90] s). CONCLUSIONS Induction of progressive renal failure in rats by 5/6 nephrectomy, which is accompanied by a marked increase of the serum levels of the endogenous NOS inhibitor ADMA, leads to a significantly increased heat pain threshold at 28 days. The sole infusion of ADMA into healthy rats leads to the same increase in heat pain threshold.
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Affiliation(s)
- Jan T Kielstein
- Department of Internal Medicine, Division of Nephrology and Hypertension, Medical School Hannover, Hannover, Germany.
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