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Fabbrini P, Vergani D, Malinverno A, Pieruzzi F, Marengo M, Merlotti G, Medana C, Quercia AD, Cantaluppi V. Protein-Bound Uremic Toxins and Inflammation Process in Hemodialysis Patients: Is There a Role for Adsorption Hemodiafiltration? Blood Purif 2024:1-10. [PMID: 39047694 DOI: 10.1159/000540402] [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: 04/12/2023] [Accepted: 07/07/2024] [Indexed: 07/27/2024]
Abstract
INTRODUCTION Despite major advances in the field of dialysis, there are still some unmet needs such as reducing inflammation through adequate depuration. It is well known that the wide spectrum of pro-inflammatory and pro-atherosclerotic uremic toxins are inefficiently removed by current dialysis techniques. Adsorption seems to be an extra tool to remove toxins, but its effect and optimization have not been widely studied. The aim of this report was to present preliminary results regarding the possibility of performing hemodiafiltration with a highly adsorptive polymethylmethacrylate membrane. METHODS The study was first conducted in 10 patients in which the safety and feasibility of hemodiafiltration with PMMA BG-U 2.1 membrane were tested through measurement of hemolysis indices, transmembrane pressures, and dialysis adequacy. Twenty patients were prospectively observed for 18-month period in which they consecutively underwent standard hemodialysis, standard post-dilution hemodiafiltration, and polymethylmethacrylate-based post-dilution hemodiafiltration. Protein-bound uremic toxins concentrations and inflammatory markers were measured throughout the observed period. RESULTS HDF-PMMA was inferior to HDF in convective volume, but KT/V was similar, and no differences were noted in operating pressures during the two treatments. During HDF-PMMA period of treatment, we observed a significant reduction of CPR levels, and HDF-PMMA was superior to all other treatments in hepcidin removal even if this did not significantly affect hemoglobin levels. HDF-PMMA could significantly reduce indoxyl sulfate (indoxyl) concentration over a period of 6 months but not for p-cresyl sulfate (p-cresyl). CONCLUSION PMMA BG-U 2.1 membrane can be safely and efficiently used in hemodiafiltration. Moreover, as these preliminary results show, adding adsorption properties to convection and diffusion enabled an increased removal of indoxyl uremic toxin associated to a reduction in inflammation markers as CRP and hepcidin without any negative impact on albumin levels.
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Affiliation(s)
- Paolo Fabbrini
- Nephrology Department, ASST-Nord milano, AO Bassini, Cinisello Balsamo-Milano, Italy
| | - Denise Vergani
- Nephrology Department, Università degli Studi di Milano Bicocca, Monza, Italy
| | - Anna Malinverno
- Nephrology Department, Università degli Studi di Milano Bicocca, Monza, Italy
| | - Federico Pieruzzi
- Nephrology Department, Università degli Studi di Milano Bicocca, Monza, Italy
| | - Marita Marengo
- Unit of Nephrology and Dialysis, Department of Medical Specialties, Cuneo, Italy
| | - Guido Merlotti
- Nephrology and Kidney Transplantation Unit, Department of Translational Medicine (DIMET), University of Piemonte Orientale (UPO), "Maggiore della Carità" University Hospital, Novara, Italy
| | - Claudio Medana
- Department of Molecular Biotechnology and Health Sciences, University of Turin, Turin, Italy
| | | | - Vincenzo Cantaluppi
- Nephrology and Kidney Transplantation Unit, Department of Translational Medicine (DIMET), University of Piemonte Orientale (UPO), "Maggiore della Carità" University Hospital, Novara, Italy
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Lee H, Liu KH, Yang YH, Liao JD, Lin BS, Wu ZZ, Chang AC, Tseng CC, Wang MC, Tsai YS. Advances in uremic toxin detection and monitoring in the management of chronic kidney disease progression to end-stage renal disease. Analyst 2024; 149:2784-2795. [PMID: 38647233 DOI: 10.1039/d4an00057a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/25/2024]
Abstract
Patients with end-stage kidney disease (ESKD) rely on dialysis to remove toxins and stay alive. However, hemodialysis alone is insufficient to completely remove all/major uremic toxins, resulting in the accumulation of specific toxins over time. The complexity of uremic toxins and their varying clearance rates across different dialysis modalities poses significant challenges, and innovative approaches such as microfluidics, biomarker discovery, and point-of-care testing are being investigated. This review explores recent advances in the qualitative and quantitative analysis of uremic toxins and highlights the use of innovative methods, particularly label-mediated and label-free surface-enhanced Raman spectroscopy, primarily for qualitative detection. The ability to analyze uremic toxins can optimize hemodialysis settings for more efficient toxin removal. Integration of multiple omics disciplines will also help identify biomarkers and understand the pathogenesis of ESKD, provide deeper understanding of uremic toxin profiling, and offer insights for improving hemodialysis programs. This review also highlights the importance of early detection and improved understanding of chronic kidney disease to improve patient outcomes.
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Affiliation(s)
- Han Lee
- Laboratory of Engineered Materials for Biomedical Applications, Department of Materials Science and Engineering, National Cheng Kung University, 1 University Road, Tainan 701, Taiwan.
| | - Kuan-Hung Liu
- Division of Nephrology, Department of Internal Medicine, National Cheng Kung University Hospital, College of Medicine, National Cheng Kung University, No.1, University Road, Tainan City, 701, Taiwan.
| | - Yu-Hsuan Yang
- Division of Nephrology, Department of Internal Medicine, National Cheng Kung University Hospital, College of Medicine, National Cheng Kung University, No.1, University Road, Tainan City, 701, Taiwan.
| | - Jiunn-Der Liao
- Laboratory of Engineered Materials for Biomedical Applications, Department of Materials Science and Engineering, National Cheng Kung University, 1 University Road, Tainan 701, Taiwan.
| | - Bo-Shen Lin
- Laboratory of Engineered Materials for Biomedical Applications, Department of Materials Science and Engineering, National Cheng Kung University, 1 University Road, Tainan 701, Taiwan.
| | - Zheng-Zhe Wu
- Division of Nephrology, Department of Internal Medicine, National Cheng Kung University Hospital, College of Medicine, National Cheng Kung University, No.1, University Road, Tainan City, 701, Taiwan.
| | - Alice Chinghsuan Chang
- Center for Measurement Standards, Industrial Technology Research Institute, No. 321, Kuang Fu Road, Section 2, Hsinchu 300, Taiwan.
| | - Chin-Chung Tseng
- Division of Nephrology, Department of Internal Medicine, National Cheng Kung University Hospital, College of Medicine, National Cheng Kung University, No.1, University Road, Tainan City, 701, Taiwan.
| | - Ming-Cheng Wang
- Division of Nephrology, Department of Internal Medicine, National Cheng Kung University Hospital, College of Medicine, National Cheng Kung University, No.1, University Road, Tainan City, 701, Taiwan.
| | - Yau-Sheng Tsai
- Center for Clinical Medicine Research, College of Medicine, National Cheng Kung University, No.1, University Road, Tainan City, 701, Taiwan.
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Sánchez-Ospina D, Mas-Fontao S, Gracia-Iguacel C, Avello A, González de Rivera M, Mujika-Marticorena M, Gonzalez-Parra E. Displacing the Burden: A Review of Protein-Bound Uremic Toxin Clearance Strategies in Chronic Kidney Disease. J Clin Med 2024; 13:1428. [PMID: 38592263 PMCID: PMC10934686 DOI: 10.3390/jcm13051428] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2024] [Revised: 02/19/2024] [Accepted: 02/28/2024] [Indexed: 04/10/2024] Open
Abstract
Uremic toxins (UTs), particularly protein-bound uremic toxins (PBUTs), accumulate in chronic kidney disease (CKD) patients, causing significant health complications like uremic syndrome, cardiovascular disease, and immune dysfunction. The binding of PBUTs to plasma proteins such as albumin presents a formidable challenge for clearance, as conventional dialysis is often insufficient. With advancements in the classification and understanding of UTs, spearheaded by the European Uremic Toxins (EUTox) working group, over 120 molecules have been identified, prompting the development of alternative therapeutic strategies. Innovations such as online hemodiafiltration aim to enhance the removal process, while novel adsorptive therapies offer a means to address the high affinity of PBUTs to plasma proteins. Furthermore, the exploration of molecular displacers, designed to increase the free fraction of PBUTs, represents a cutting-edge approach to facilitate their dialytic clearance. Despite these advancements, the clinical application of displacers requires more research to confirm their efficacy and safety. The pursuit of such innovative treatments is crucial for improving the management of uremic toxicity and the overall prognosis of CKD patients, emphasizing the need for ongoing research and clinical trials.
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Affiliation(s)
- Didier Sánchez-Ospina
- Servicio Análisis Clínicos, Hospital Universitario de Burgos, 09006 Burgos, Spain; (D.S.-O.); (M.M.-M.)
| | - Sebastián Mas-Fontao
- IIS-Fundación Jiménez Díaz, 28040 Madrid, Spain;
- Centro de Investigación Biomédica en Red de Diabetes y Enfermedades Metabólicas Asociadas (CIBERDEM), 28029 Madrid, Spain
- Faculty of Medicine and Biomedicine, Universidad Alfonso X el Sabio (UAX), 28037 Madrid, Spain
| | - Carolina Gracia-Iguacel
- Department of Nephrology and Hypertension, IIS-Fundación Jiménez Díaz, Univerdad Autonoma de madrid, 28049 Madrid, Spain; (C.G.-I.); (A.A.); (M.G.d.R.)
| | - Alejandro Avello
- Department of Nephrology and Hypertension, IIS-Fundación Jiménez Díaz, Univerdad Autonoma de madrid, 28049 Madrid, Spain; (C.G.-I.); (A.A.); (M.G.d.R.)
| | - Marina González de Rivera
- Department of Nephrology and Hypertension, IIS-Fundación Jiménez Díaz, Univerdad Autonoma de madrid, 28049 Madrid, Spain; (C.G.-I.); (A.A.); (M.G.d.R.)
| | | | - Emilio Gonzalez-Parra
- IIS-Fundación Jiménez Díaz, 28040 Madrid, Spain;
- Department of Nephrology and Hypertension, IIS-Fundación Jiménez Díaz, Univerdad Autonoma de madrid, 28049 Madrid, Spain; (C.G.-I.); (A.A.); (M.G.d.R.)
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Wu CC, Tian YC, Lu CL, Wu MJ, Lim PS, Chiu YW, Kuo KL, Liu SH, Chou YC, Sun CA, Hou YC, Lu KC. AST-120 improved uremic pruritus by lowering indoxyl sulfate and inflammatory cytokines in hemodialysis patients. Aging (Albany NY) 2024; 16:4236-4249. [PMID: 38385990 PMCID: PMC10968676 DOI: 10.18632/aging.205580] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2023] [Accepted: 01/17/2024] [Indexed: 02/23/2024]
Abstract
BACKGROUND AND HYPOTHESIS Pruritus is a common and distressing symptom that affects patients with chronic kidney disease. The concentration of protein bounded uremic toxin was associated with the uremic pruritus. The aim is to assess the efficacy of AST-120 for uremic pruritus in hemodialysis patients. MATERIALS AND METHODS The participants were enrolled and then divided into the AST-120 treatment group and control group with a ratio of 2:1. All participants underwent pre-observation screenings two weeks before the study with three visits. In the treatment phase (week 1 to week 4), the treatment group added 6g/day of AST-120 along with routine anti-pruritic treatment. Visual analog scale (VAS) and biochemical parameters were measured. RESULTS The VAS score began to be lower in the AST-120 treatment group after the 5th visiting (p < 0.05). The reduction in indoxyl sulfate (IS) at 5th week along with TNF-alpha. The reduction ratio of indoxyl sulfate correlated with reduction of parathyroid hormone. CONCLUSION This study has demonstrated that the four-week treatment of AST-120 decreased the severity of uremic pruritus in patients with ESRD. The concentration of IS and TNF-alpha decreased in the AST-120 treatment group. The reduction of iPTH correlated with the reduction of IS in the AST-120 treatment.
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Affiliation(s)
- Chia-Chao Wu
- Division of Nephrology, Department of Internal Medicine, Tri-Service General Hospital, National Defense Medical Center, Taipei 11490, Taiwan
- Department and Graduate Institute of Microbiology and Immunology, National Defense Medical Center, Taipei 11490, Taiwan
| | - Ya-Chung Tian
- Kidney Research Center, Department of Nephrology, Chang Gung Memorial Hospital, Taoyuan City 33303, Taiwan
| | - Chien-Lin Lu
- School of Medicine, College of Medicine, Fu Jen Catholic University, New Taipei City 24205, Taiwan
- Division of Nephrology, Department of Medicine, Fu Jen Catholic University Hospital, New Taipei City 24352, Taiwan
| | - Ming-Ju Wu
- Division of Nephrology, Department of Internal Medicine, Taichung Veterans General Hospital, Taichung 40705, Taiwan
- Department of Post-Baccalaureate Medicine, College of Medicine, National Chung Hsing University, Taichung 40227, Taiwan
| | - Paik-Seong Lim
- Division of Nephrology, Department of Internal Medicine, Tungs’ Taichung Metroharbour Hospital, Taichung 43503, Taiwan
| | - Yi-Wen Chiu
- Division of Nephrology, Department of Internal Medicine, Kaohsiung Medical University Hospital, Kaohsiung 80756, Taiwan
- Faculty of Medicine, Kaohsiung Medical University, Kaohsiung 80708, Taiwan
| | - Ko-Lin Kuo
- Division of Nephrology, Department of Medicine, Taipei Tzu Chi Hospital, Buddhist Tzu Chi Medical Foundation, New Taipei City 23142, Taiwan
- School of Medicine, Buddhist Tzu Chi University, Hualien 97004, Taiwan
- School of Post-Baccalaureate Chinese Medicine, Buddhist Tzu Chi University, Hualien 97004, Taiwan
| | - Shou-Hsuan Liu
- Department of Nephrology, Department of Internal Medicine, Chang Gung Memorial Hospital, Taoyuan City 33303, Taiwan
| | - Yu-Ching Chou
- School of Public Health, National Defense Medical Center, Taipei 11490, Taiwan
| | - Chien-An Sun
- Department of Public Health, College of Medicine, Fu-Jen Catholic University, New Taipei City 24205, Taiwan
- Big Data Research Center, College of Medicine, Fu-Jen Catholic University, New Taipei City 24205, Taiwan
| | - Yi-Chou Hou
- School of Medicine, College of Medicine, Fu Jen Catholic University, New Taipei City 24205, Taiwan
- Division of Nephrology, Department of Internal Medicine, Cardinal-Tien Hospital, New Taipei City 23155, Taiwan
| | - Kuo-Cheng Lu
- Division of Nephrology, Department of Medicine, Taipei Tzu Chi Hospital, Buddhist Tzu Chi Medical Foundation, New Taipei City 23142, Taiwan
- Division of Nephrology, Department of Medicine, Fu-Jen Catholic University Hospital, School of Medicine, Fu-Jen Catholic University, New Taipei City 24352, Taiwan
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Zwaenepoel B, De Backer T, Glorieux G, Verbeke F. Predictive value of protein-bound uremic toxins for heart failure in patients with chronic kidney disease. ESC Heart Fail 2024; 11:466-474. [PMID: 38041505 PMCID: PMC10804180 DOI: 10.1002/ehf2.14566] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2023] [Revised: 10/05/2023] [Accepted: 10/08/2023] [Indexed: 12/03/2023] Open
Abstract
AIMS This retrospective cohort study aimed to be the first to evaluate the association between plasma protein-bound uremic toxins (PBUTs) concentrations, echocardiographic parameters of heart failure (HF), and incident HF events in patients with chronic kidney disease (CKD) not on dialysis. METHODS AND RESULTS Retrospective, single-centre, cohort study at the Ghent University Hospital, Belgium. Adults with CKD stages G1-G5, not on dialysis, could be included. Exclusion criteria were ongoing pregnancy, age <18 years, active acute infection, active malignancy, history of transplantation, or a cardiovascular event within 3 months prior to inclusion. Free and total concentrations of five PBUTs were quantified at baseline: indoxyl sulfate (IxS), p-cresyl sulfate (pCS), p-cresyl glucuronide (pCG), indole-3 acetic acid (IAA), and hippuric acid (HA). Patients were grouped into three echocardiographic categories: normal left ventricular ejection fraction (LVEF) and normal left ventricular end-diastolic pressure (LVEDP), normal LVEF and increased LVEDP, and reduced LVEF, based on available echocardiographic data in a time interval of ±6 months around the plasma sample collection. A total of 523 patients were included between January 2011 and January 2014. Echocardiographic data within the predefined timeframe were available for 210 patients (40% of patients). Levels of pCG and pCS were significantly higher in patients with reduced (<50%) versus normal LVEF (P < 0.05). After a median follow-up 5.5 years, 43 (8.4%) patients reached the composite endpoint of hospitalization or mortality due to HF. Free fractions of IxS, pCS, and pCG showed the strongest association with clinical outcome: free IxS: HR 1.71 (95% CI 1.11-2.63; P = 0.015), free pCS: HR 1.82 (95% CI 1.11-3.01; P = 0.019), and free pCG: HR 1.67 (95% CI 1.08-2.58; P = 0.020), and these results were independent of age, gender, body mass index, diabetes, and systolic blood pressure. In models that were also adjusted for serum creatinine, the free fractions of these PBUTs remained significant. CONCLUSIONS Elevated free concentrations of IxS, pCG, and pCS were independently associated with an increased risk of HF events in non-dialysed CKD patients. Further research is necessary to confirm these findings and investigate the potential impact of PBUT-lowering interventions on HF events in this patient group.
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Affiliation(s)
- Bert Zwaenepoel
- Department of CardiologyGhent University Hospital, Ghent UniversityGhentBelgium
| | - Tine De Backer
- Department of CardiologyGhent University Hospital, Ghent UniversityGhentBelgium
| | - Griet Glorieux
- Department of NephrologyGhent University Hospital, Ghent UniversityGhentBelgium
| | - Francis Verbeke
- Department of NephrologyGhent University Hospital, Ghent UniversityGhentBelgium
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Kawanishi H. Middle Molecular Uremic Toxin and Blood Purification Therapy. J Clin Med 2024; 13:647. [PMID: 38337341 PMCID: PMC10856111 DOI: 10.3390/jcm13030647] [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: 12/21/2023] [Revised: 01/18/2024] [Accepted: 01/20/2024] [Indexed: 02/12/2024] Open
Abstract
The purpose of blood purification therapy is to remove uremic toxins, and middle molecules (MMs) are a specific target. An MM is defined as a solute that passes through the glomerulus with a molecular weight in the range of 0.5-58 kDa, and new classifications of "small-middle 0.5-15 kDa," "medium-middle 15-25 kDa," and "large-middle 25-58 kDa" were proposed. In Japan, the removal of α1-microglobulin (αMG) in the large-middle range has been the focus, but a new theory of removal has been developed, emphasizing the antioxidant effect of αMG as a physiological function. Clinical proof of this mechanism will lead to further development of blood purification therapies.
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Affiliation(s)
- Hideki Kawanishi
- Tsuchiya General Hospital, 3-30 Nakajima-cho Naka-ku, Hiroshima 730-8655, Japan
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Fiorentino M, La Fergola F, De Rosa S. Medium cut-off dialyzer for middle molecular uremic toxins in AKI and chronic dialysis. J Nephrol 2024; 37:23-37. [PMID: 37843731 PMCID: PMC10920419 DOI: 10.1007/s40620-023-01771-0] [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: 04/11/2023] [Accepted: 08/18/2023] [Indexed: 10/17/2023]
Abstract
Uremic toxins accumulate in patients affected by renal failure and can deposit in different organs, including the kidneys and heart. Given their physicochemical characteristics, uremic toxins can contribute to organ dysfunction due to several pathobiological actions at cellular and molecular levels. Several uremic compounds have been described in serum and plasma from patients with acute kidney injury (AKI) and kidney failure; they are usually classified based on their molecular size and protein-binding properties. In this scenario, new dialytic approaches have been proposed in the last few years with the aim of improving uremic toxin removal. Recent studies which focused on the use of medium cut-off membranes in patients on chronic hemodialysis have shown a discrete ability to remove β2-microglobulin and other middle molecules, such as kappa and lambda free light chains, complement factor D and α1-microglobulin. However, current evidence is mainly based on the impact on short-term outcomes and, consequently, longer observational studies are necessary to confirm the efficacy and safety of the medium cut-off dialyzer. Here we present the state-of-the-art on the clinical application of medium cut-off membranes in AKI and chronic dialysis patients.
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Affiliation(s)
- Marco Fiorentino
- Nephrology, Dialysis and Transplantation Unit, Department of Precision and Regenerative Medicine and Ionian Area (DiMePRe-J), University of Bari "Aldo Moro", Bari, Italy
| | - Francesco La Fergola
- Nephrology, Dialysis and Transplantation Unit, Department of Precision and Regenerative Medicine and Ionian Area (DiMePRe-J), University of Bari "Aldo Moro", Bari, Italy
| | - Silvia De Rosa
- Centre for Medical Sciences - CISMed, University of Trento, Via S. Maria Maddalena 1, 38122, Trento, Italy.
- Anesthesia and Intensive Care, Santa Chiara Regional Hospital, APSS Trento, Trento, Italy.
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Tourountzis T, Lioulios G, Van Laecke S, Ginikopoulou E, Nikolaidou V, Moysidou E, Stai S, Christodoulou M, Fylaktou A, Glorieux G, Stangou M. Immunosenescence and Immune Exhaustion Are Associated with Levels of Protein-Bound Uremic Toxins in Patients on Hemodialysis. Biomedicines 2023; 11:2504. [PMID: 37760945 PMCID: PMC10525954 DOI: 10.3390/biomedicines11092504] [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: 08/06/2023] [Revised: 09/04/2023] [Accepted: 09/08/2023] [Indexed: 09/29/2023] Open
Abstract
BACKGROUND The accumulation of protein-bound uremic toxins (PBUTs) in chronic kidney disease may affect patients' immune status. The aim of the study was to evaluate their potential impacts on lymphocyte alterations in patients on hemodialysis (HD). METHODS The plasma levels of PBUTs were assessed in 54 patients on HD and 31 healthy individuals, using ultra-performance liquid chromatography. The results correlated with the senescent and exhausted status of lymphocytes, based on certain surface molecules, analyzed by flow cytometry. RESULTS The plasma levels of PBUTs were significantly increased in the patients on HD compared with the healthy controls. The patients with residual kidney function had reduced hippuric acid (HA) levels, total (p = 0.03) and free (p = 0.04), and free IxS levels (p = 0.02). The total and free HA levels correlated negatively with less differentiated subpopulations, CD4+CD45RA+CD31+ (p = 0.037 and p = 0.027), CD8+CD28+CD57- (p = 0.01, p = 0.01), and naïve B cells (CD19+IgD+CD27-) (p = 0.04, p = 0.03). Both the total and the free pCS levels correlated positively with exhausted CD4 cells, p = 0.02 and p = 0.01, respectively. A multivariate analysis showed that IxS and age were the main independent parameters implicated in the reduction intotal CD4 and B lymphocytes and their naïve and early differentiated subsets. CONCLUSIONS Increased PBUTs levels are associated with immune disturbances of patients on HD, HA, and IxS in the immunosenescent and pCS in the immunoexhaustion alterations.
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Affiliation(s)
| | - Georgios Lioulios
- Department of Nephrology, General Hospital “Hippokratio”, School of Medicine, Aristotle University of Thessaloniki, 54642 Thessaloniki, Greece; (G.L.); (E.M.); (S.S.); (M.C.); (M.S.)
| | - Steven Van Laecke
- Department of Internal Medicine and Pediatrics, Nephrology Unit, Ghent University Hospital, 9000 Gent, Belgium; (S.V.L.); (G.G.)
| | | | - Vasiliki Nikolaidou
- Department of Immunology, National Peripheral Histocompatibility Center, General Hospital “Hippokratio”, 54642 Thessaloniki, Greece; (V.N.); (A.F.)
| | - Eleni Moysidou
- Department of Nephrology, General Hospital “Hippokratio”, School of Medicine, Aristotle University of Thessaloniki, 54642 Thessaloniki, Greece; (G.L.); (E.M.); (S.S.); (M.C.); (M.S.)
| | - Stamatia Stai
- Department of Nephrology, General Hospital “Hippokratio”, School of Medicine, Aristotle University of Thessaloniki, 54642 Thessaloniki, Greece; (G.L.); (E.M.); (S.S.); (M.C.); (M.S.)
| | - Michalis Christodoulou
- Department of Nephrology, General Hospital “Hippokratio”, School of Medicine, Aristotle University of Thessaloniki, 54642 Thessaloniki, Greece; (G.L.); (E.M.); (S.S.); (M.C.); (M.S.)
| | - Asimina Fylaktou
- Department of Immunology, National Peripheral Histocompatibility Center, General Hospital “Hippokratio”, 54642 Thessaloniki, Greece; (V.N.); (A.F.)
| | - Griet Glorieux
- Department of Internal Medicine and Pediatrics, Nephrology Unit, Ghent University Hospital, 9000 Gent, Belgium; (S.V.L.); (G.G.)
| | - Maria Stangou
- Department of Nephrology, General Hospital “Hippokratio”, School of Medicine, Aristotle University of Thessaloniki, 54642 Thessaloniki, Greece; (G.L.); (E.M.); (S.S.); (M.C.); (M.S.)
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Faria J, Ahmed S, Stamatialis D, Verhaar MC, Masereeuw R, Gerritsen KGF, Mihăilă SM. Bioengineered Kidney Tubules Efficiently Clear Uremic Toxins in Experimental Dialysis Conditions. Int J Mol Sci 2023; 24:12435. [PMID: 37569805 PMCID: PMC10419568 DOI: 10.3390/ijms241512435] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2023] [Revised: 07/25/2023] [Accepted: 08/02/2023] [Indexed: 08/13/2023] Open
Abstract
Patients with end-stage kidney disease (ESKD) suffer from high levels of protein-bound uremic toxins (PBUTs) that contribute to various comorbidities. Conventional dialysis methods are ineffective in removing these PBUTs. A potential solution could be offered by a bioartificial kidney (BAK) composed of porous membranes covered by proximal tubule epithelial cells (PTECs) that actively secrete PBUTs. However, BAK development is currently being hampered by a lack of knowledge regarding the cytocompatibility of the dialysis fluid (DF) that comes in contact with the PTECs. Here, we conducted a comprehensive functional assessment of the DF on human conditionally immortalized PTECs (ciPTECs) cultured as monolayers in well plates, on Transwell® inserts, or on hollow fiber membranes (HFMs) that form functional units of a BAK. We evaluated cell viability markers, monolayer integrity, and PBUT clearance. Our results show that exposure to DF did not affect ciPTECs' viability, membrane integrity, or function. Seven anionic PBUTs were efficiently cleared from the perfusion fluid containing a PBUTs cocktail or uremic plasma, an effect which was enhanced in the presence of albumin. Overall, our findings support that the DF is cytocompatible and does not compromise ciPTECs function, paving the way for further advancements in BAK development and its potential clinical application.
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Affiliation(s)
- João Faria
- Division of Pharmacology, Utrecht Institute for Pharmaceutical Sciences, Utrecht University, 3584 CG Utrecht, The Netherlands; (J.F.); (S.A.); (R.M.)
| | - Sabbir Ahmed
- Division of Pharmacology, Utrecht Institute for Pharmaceutical Sciences, Utrecht University, 3584 CG Utrecht, The Netherlands; (J.F.); (S.A.); (R.M.)
| | - Dimitrios Stamatialis
- Advanced Organ Bioengineering and Therapeutics, Faculty of Science and Technology, Technical Medical Centre, University of Twente, 7522 NB Enschede, The Netherlands;
| | - Marianne C. Verhaar
- Department of Nephrology and Hypertension, University Medical Center, 3508 GA Utrecht, The Netherlands; (M.C.V.); (K.G.F.G.)
| | - Rosalinde Masereeuw
- Division of Pharmacology, Utrecht Institute for Pharmaceutical Sciences, Utrecht University, 3584 CG Utrecht, The Netherlands; (J.F.); (S.A.); (R.M.)
| | - Karin G. F. Gerritsen
- Department of Nephrology and Hypertension, University Medical Center, 3508 GA Utrecht, The Netherlands; (M.C.V.); (K.G.F.G.)
| | - Silvia M. Mihăilă
- Division of Pharmacology, Utrecht Institute for Pharmaceutical Sciences, Utrecht University, 3584 CG Utrecht, The Netherlands; (J.F.); (S.A.); (R.M.)
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Meyer TW, Lee S, Whitmer LC, Blanco IJ, Suba JK, Sirich TL. Increasing the Clearance of Protein-Bound Solutes by Recirculating Dialysate through Activated Carbon. KIDNEY360 2023; 4:e744-e750. [PMID: 37211642 PMCID: PMC10371360 DOI: 10.34067/kid.0000000000000155] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/15/2023] [Accepted: 04/05/2023] [Indexed: 05/23/2023]
Abstract
Key Points Conventional hemodialysis provides limited clearance of uremic solutes that bind to plasma proteins. No studies have yet tested whether increasing the clearance of bound solutes provides clinical benefit. Practical means to increase the dialytic clearance of bound solutes are required to perform such studies. Background Conventional hemodialysis provides limited clearance of uremic solutes that bind to plasma proteins. However, no studies have tested whether increasing the clearance of bound solutes provides clinical benefit. Practical means to increase the dialytic clearance of bound solutes are required to perform such studies. Methods Artificial plasma was dialyzed using two dialysis systems in series. In the first recirculating system, a fixed small volume of dialysate flowed rapidly through an activated carbon block before passing through two large dialyzers. In a second conventional system, a lower flow of fresh dialysate was passed through a single dialyzer. Chemical measurements tested the ability of the recirculating system to increase the clearance of selected solutes. Mathematical modeling predicted the dependence of solute clearances on the extent to which solutes were taken up by the carbon block and were bound to plasma proteins. Results By itself, the conventional system provided clearances of the tightly bound solutes p-cresol sulfate and indoxyl sulfate of only 18±10 and 19±11 ml/min, respectively (mean±SD). Because these solutes were effectively adsorbed by the carbon block, the recirculating system by itself provided p-cresol sulfate and indoxyl sulfate clearances of 45±11 and 53±16 ml/min. It further raised their clearances to 54±12 and 61±17 ml/min when operating in series with the conventional system (P < 0.002 versus conventional clearance both solutes). Modeling predicted that the recirculating system would increase the clearances of bound solute even if their uptake by the carbon block was incomplete. Conclusions When added to a conventional dialysis system, a recirculating system using a carbon block sorbent, a single pump, and standard dialyzers can greatly increase the clearance of protein-bound uremic solutes.
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Affiliation(s)
- Timothy W. Meyer
- The Department of Medicine, Stanford University, Palo Alto, California
- The Department of Medicine, VA Palo Alto Healthcare System, Palo Alto, California
| | - Seolhyun Lee
- The Department of Medicine, Stanford University, Palo Alto, California
- The Department of Medicine, VA Palo Alto Healthcare System, Palo Alto, California
| | - Luke C. Whitmer
- The Department of Medicine, Stanford University, Palo Alto, California
- The Department of Medicine, VA Palo Alto Healthcare System, Palo Alto, California
| | - Ignacio J. Blanco
- The Department of Medicine, Stanford University, Palo Alto, California
- The Department of Medicine, VA Palo Alto Healthcare System, Palo Alto, California
| | - Josef K. Suba
- The Department of Medicine, Stanford University, Palo Alto, California
- The Department of Medicine, VA Palo Alto Healthcare System, Palo Alto, California
| | - Tammy L. Sirich
- The Department of Medicine, Stanford University, Palo Alto, California
- The Department of Medicine, VA Palo Alto Healthcare System, Palo Alto, California
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11
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Pro-Arrhythmic Potential of Accumulated Uremic Toxins Is Mediated via Vulnerability of Action Potential Repolarization. Int J Mol Sci 2023; 24:ijms24065373. [PMID: 36982449 PMCID: PMC10049510 DOI: 10.3390/ijms24065373] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2023] [Revised: 03/08/2023] [Accepted: 03/09/2023] [Indexed: 03/14/2023] Open
Abstract
Chronic kidney disease (CKD) is represented by a diminished filtration capacity of the kidneys. End-stage renal disease patients need dialysis treatment to remove waste and toxins from the circulation. However, endogenously produced uremic toxins (UTs) cannot always be filtered during dialysis. UTs are among the CKD-related factors that have been linked to maladaptive and pathophysiological remodeling of the heart. Importantly, 50% of the deaths in dialysis patients are cardiovascular related, with sudden cardiac death predominating. However, the mechanisms responsible remain poorly understood. The current study aimed to assess the vulnerability of action potential repolarization caused by exposure to pre-identified UTs at clinically relevant concentrations. We exposed human induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs) and HEK293 chronically (48 h) to the UTs indoxyl sulfate, kynurenine, or kynurenic acid. We used optical and manual electrophysiological techniques to assess action potential duration (APD) in the hiPSC-CMs and recorded IKr currents in stably transfected HEK293 cells (HEK-hERG). Molecular analysis of KV11.1, the ion channel responsible for IKr, was performed to further understand the potential mechanism underlying the effects of the UTs. Chronic exposure to the UTs resulted in significant APD prolongation. Subsequent assessment of the repolarization current IKr, often most sensitive and responsible for APD alterations, showed decreased current densities after chronic exposure to the UTs. This outcome was supported by lowered protein levels of KV11.1. Finally, treatment with an activator of the IKr current, LUF7244, could reverse the APD prolongation, indicating the potential modulation of electrophysiological effects caused by these UTs. This study highlights the pro-arrhythmogenic potential of UTs and reveals a mode of action by which they affect cardiac repolarization.
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12
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Ma K, Zheng ZR, Meng Y. Pathogenesis of Chronic Kidney Disease Is Closely Bound up with Alzheimer's Disease, Especially via the Renin-Angiotensin System. J Clin Med 2023; 12:jcm12041459. [PMID: 36835994 PMCID: PMC9966558 DOI: 10.3390/jcm12041459] [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] [Received: 12/12/2022] [Revised: 02/01/2023] [Accepted: 02/07/2023] [Indexed: 02/15/2023] Open
Abstract
Chronic kidney disease (CKD) is a clinical syndrome secondary to the definitive change in function and structure of the kidney, which is characterized by its irreversibility and slow and progressive evolution. Alzheimer's disease (AD) is characterized by the extracellular accumulation of misfolded β-amyloid (Aβ) proteins into senile plaques and the formation of neurofibrillary tangles (NFTs) containing hyperphosphorylated tau. In the aging population, CKD and AD are growing problems. CKD patients are prone to cognitive decline and AD. However, the connection between CKD and AD is still unclear. In this review, we take the lead in showing that the development of the pathophysiology of CKD may also cause or exacerbate AD, especially the renin-angiotensin system (RAS). In vivo studies had already shown that the increased expression of angiotensin-converting enzyme (ACE) produces a positive effect in aggravating AD, but ACE inhibitors (ACEIs) have protective effects against AD. Among the possible association of risk factors in CKD and AD, we mainly discuss the RAS in the systemic circulation and the brain.
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Affiliation(s)
- Ke Ma
- The First Affiliated Hospital of Jinan University, Guangzhou 510000, China
| | - Zi-Run Zheng
- The First Affiliated Hospital of Jinan University, Guangzhou 510000, China
| | - Yu Meng
- The First Affiliated Hospital of Jinan University, Guangzhou 510000, China
- Central Laboratory, The Fifth Affiliated Hospital of Jinan University, Heyuan 517000, China
- Institute of Nephrology, Jinan University, Guangzhou 510000, China
- Correspondence:
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13
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Acevedo S, M. Andrade J. Effects of a spice-blended honey muffin on salivary inflammation markers in adults with obesity: a feasibility trial. Ann Med 2023; 55:2245325. [PMID: 37566728 PMCID: PMC10424601 DOI: 10.1080/07853890.2023.2245325] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/14/2023] [Revised: 04/17/2023] [Accepted: 08/02/2023] [Indexed: 08/13/2023] Open
Abstract
BACKGROUND Obesity is considered a low-grade chronically inflamed state that contributes to communicable chronic diseases. This inflammation may be modulated by consuming spices like turmeric daily. However, few studies have looked at the inclusion of spice within whole foods. OBJECTIVE The purpose of this feasibility pre/posttrial was to assess the influence of turmeric in a muffin on salivary IL-6 and CRP in adults who were obese. METHODS Participants consumed one, 60-gram muffin containing 3 g turmeric for 10 days. Participants provided a urinary sample at baseline, a 2-ml saliva sample, and a 30-day food frequency and spice consumption questionnaire at baseline and post-trial. A one-sample t-test was conducted using SAS v 9.4 with significance determined at p < 0.05. RESULTS A total of 14 participants, average BMI of 32.16 kg/m2 with 10 identifying as female, completed the trial after 5 dropped due to various reasons. The visit lengths and collection of data with participants adhering to the instructions were deemed a success. There was a significant decrease in salivary IL-6 (p = 0.03) but no statistical difference in salivary CRP (p = 0.46). Participants consumed fruits and vegetables at least once daily, chicken and eggs 5-6 times per week, and beef, pork, and fish at least once per week. Participants consumed chili pepper, garlic, cinnamon, cilantro, and ginger at least once per week. No changes were observed in dietary/spice habits during this trial. CONCLUSION The feasibility pre/post study revealed that consumption of a muffin with turmeric reduced at least salivary IL-6 in 10 days. Modifications to the study design such as lengthier trial time to assess the impact of this muffin on CRP is necessary prior to implementing larger-scale randomized control trials.
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Affiliation(s)
- Sofia Acevedo
- University of FL Food Science and Human Nutrition Department, Gainesville, FL, USA
| | - Jeanette M. Andrade
- University of FL Food Science and Human Nutrition Department, Gainesville, FL, USA
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14
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Chen Z, Xu J, Xing X, Xue C, Luo X, Gao S, Mao Z. p-Cresyl sulfate predicts clinical outcomes in sustained peritoneal dialysis: a 5-year follow-up cohort study and meta-analysis. Ren Fail 2022; 44:1791-1800. [PMID: 36278836 PMCID: PMC9602922 DOI: 10.1080/0886022x.2022.2136528] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Background The impact of p-cresyl sulfate (PCS) and indoxyl sulfate (IS) on the prognosis of patients with uremia remains controversial. We performed a prospective study on peritoneal dialysis (PD) to investigate the relationship between PCS or IS levels with clinical outcomes. Methods This prospective cohort study investigated the association of serum PCS and IS with clinical outcomes in patients undertaking PD. We performed a correlations analysis to explore the influencing factors of PCS an IS. Meta-analysis was conducted to objectively evaluate the prognostic effects of PCS and IS on different stages of CKD patients. Results A total of 127 patients were enrolled consecutively and followed with an average period of 51.3 months. Multivariate Cox regression showed that serum total PCS not only contributed to the occurrence of PD failure event (HR: 1.05, 95% CI = 1.02 to 1.07, p < 0.001), but also increased the risk of cardiovascular event (HR: 1.08, 95% CI = 1.04 to 1.13, p < 0.001) and PD-associated peritonitis (HR: 1.04, 95% CI = 1.02 to 1.08, p = 0.001). Dividing the total PCS level by 18.99 mg/L, which was calculated from the best cutoff value of the ROC curve, patients with total PCS higher than 18.99 mg/L had worse prognosis. Meta-analysis confirmed its value in cardiovascular event in PD. Conclusion The serum total PCS concentration was a detrimental factor for higher PD failure event, cardiovascular event, and PD-associated peritonitis. It could be used as an innovative marker in predicting poor clinical outcome in PD.
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Affiliation(s)
- Zewei Chen
- Kidney Institute, Department of Nephrology, Shanghai Changzheng Hospital, Second Military Medical University, Shanghai, China
| | - Jing Xu
- Kidney Institute, Department of Nephrology, Shanghai Changzheng Hospital, Second Military Medical University, Shanghai, China
| | - Xiaohong Xing
- Kidney Institute, Department of Nephrology, Shanghai Changzheng Hospital, Second Military Medical University, Shanghai, China
| | - Cheng Xue
- Kidney Institute, Department of Nephrology, Shanghai Changzheng Hospital, Second Military Medical University, Shanghai, China
| | - Xiaoling Luo
- Kidney Institute, Department of Nephrology, Shanghai Changzheng Hospital, Second Military Medical University, Shanghai, China
| | - Shouhong Gao
- Department of Pharmacy, Shanghai Changzheng Hospital, Second Military Medical University, Shanghai, China
| | - Zhiguo Mao
- Kidney Institute, Department of Nephrology, Shanghai Changzheng Hospital, Second Military Medical University, Shanghai, China
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15
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Masereeuw R. The Dual Roles of Protein-Bound Solutes as Toxins and Signaling Molecules in Uremia. Toxins (Basel) 2022; 14:toxins14060402. [PMID: 35737063 PMCID: PMC9230939 DOI: 10.3390/toxins14060402] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2022] [Revised: 03/24/2022] [Accepted: 06/10/2022] [Indexed: 01/25/2023] Open
Abstract
In patients with severe kidney disease, renal clearance is compromised, resulting in the accumulation of a plethora of endogenous waste molecules that cannot be removed by current dialysis techniques, the most often applied treatment. These uremic retention solutes, also named uremic toxins, are a heterogeneous group of organic compounds of which many are too large to be filtered and/or are protein-bound. Their renal excretion depends largely on renal tubular secretion, by which the binding is shifted towards the free fraction that can be eliminated. To facilitate this process, kidney proximal tubule cells are equipped with a range of transport proteins that cooperate in cellular uptake and urinary excretion. In recent years, innovations in dialysis techniques to advance uremic toxin removal, as well as treatments with drugs and/or dietary supplements that limit uremic toxin production, have provided some clinical improvements or are still in progress. This review gives an overview of these developments. Furthermore, the role protein-bound uremic toxins play in inter-organ communication, in particular between the gut (the side where toxins are produced) and the kidney (the side of their removal), is discussed.
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Affiliation(s)
- Rosalinde Masereeuw
- Division of Pharmacology, Utrecht Institute for Pharmaceutical Sciences, Utrecht University, 3584 CG Utrecht, The Netherlands
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16
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Lima JD, Guedes M, Rodrigues SD, Flórido ACS, Moreno-Amaral AN, Barra AB, Canziani ME, Cuvello-Neto A, Poli-de-Figueiredo CE, Pecoits-Filho R, Nakao LS. High-volume hemodiafiltration decreases the pre-dialysis concentrations of indoxyl sulfate and p-cresyl sulfate compared to hemodialysis: a post-hoc analysis from the HDFit randomized controlled trial. J Nephrol 2022; 35:1449-1456. [PMID: 35239175 DOI: 10.1007/s40620-022-01283-3] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2021] [Accepted: 02/08/2022] [Indexed: 11/24/2022]
Abstract
BACKGROUND Although high-volume online hemodiafiltration has been associated with higher clearance and lower pre-dialysis concentration of middle molecular weight toxins compared to hemodialysis, its effect on protein-bound uremic toxins has shown inconclusive results. In this study, we investigated whether hemodiafiltration impacts pre-dialysis plasma levels of the toxins indoxyl sulfate, p-cresyl sulfate, and indole-3-acetic acid compared to high-flux hemodialysis. METHODS This is a post-hoc analysis of the multicenter, randomized controlled trial HDFit (ClinicalTrials.gov: NCT02787161). Uremic toxins were determined by high performance liquid chromatography at baseline, 3, and 6 months. Mean differences in monthly changes of pre-dialysis uremic toxin concentrations between hemodiafiltration and high-flux hemodialysis were analyzed using linear mixed-effect models. RESULTS One hundred ninety-three patients (mean age 53 years old, 71% males) were analyzed. There were no differences between groups regarding clinical and biochemical characteristics at baseline or duration of dialysis session and blood flows throughout the follow-up. Mean differences in rates of change (μM/month, [confidence interval CI]) in high-flux hemodialysis vs. hemodiafiltration were 2.4 [0.3 to 4.56], 3.94 [- 1.54 to 9.41] and 0.06 [- 0.6 to 0.5] for indoxyl sulfate, p-cresyl sulfate and indole-3-acetic acid, respectively. In the exploratory analysis, these differences in high-flux hemodialysis vs. hemodiafiltration subgroup with convective volume > 27.5 L were 2.86 [0.43 to 5.28], 7.43 [0.7 to 14.16] and - 0.19 [- 0.88 to 0.50]. CONCLUSION These exploratory findings suggest that hemodiafiltration is more effective in reducing indoxyl sulfate as compared to standard high-flux hemodialysis, and also that this effect was extended to p-cresyl sulfate in patients achieving higher convective volumes.
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Affiliation(s)
- Jordana D Lima
- Department of Basic Pathology, Universidade Federal do Paraná, Curitiba, Brazil
| | - Murilo Guedes
- School of Medicine, Pontifícia Universidade Católica do Paraná, Curitiba, Brazil
| | - Silvia D Rodrigues
- Department of Basic Pathology, Universidade Federal do Paraná, Curitiba, Brazil
| | - Ana Clara S Flórido
- School of Medicine, Pontifícia Universidade Católica do Paraná, Curitiba, Brazil
| | | | | | | | | | | | - Roberto Pecoits-Filho
- School of Medicine, Pontifícia Universidade Católica do Paraná, Curitiba, Brazil.,Arbor Research Collaborative for Health, Ann Arbor, USA
| | - Lia S Nakao
- Department of Basic Pathology, Universidade Federal do Paraná, Curitiba, Brazil.
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17
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The Interplay between Uremic Toxins and Albumin, Membrane Transporters and Drug Interaction. Toxins (Basel) 2022; 14:toxins14030177. [PMID: 35324674 PMCID: PMC8949274 DOI: 10.3390/toxins14030177] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2022] [Revised: 02/21/2022] [Accepted: 02/24/2022] [Indexed: 01/10/2023] Open
Abstract
Uremic toxins are a heterogeneous group of molecules that accumulate in the body due to the progression of chronic kidney disease (CKD). These toxins are associated with kidney dysfunction and the development of comorbidities in patients with CKD, being only partially eliminated by dialysis therapies. Importantly, drugs used in clinical treatments may affect the levels of uremic toxins, their tissue disposition, and even their elimination through the interaction of both with proteins such as albumin and cell membrane transporters. In this context, protein-bound uremic toxins (PBUTs) are highlighted for their high affinity for albumin, the most abundant serum protein with multiple binding sites and an ability to interact with drugs. Membrane transporters mediate the cellular influx and efflux of various uremic toxins, which may also compete with drugs as substrates, and both may alter transporter activity or expression. Therefore, this review explores the interaction mechanisms between uremic toxins and albumin, as well as membrane transporters, considering their potential relationship with drugs used in clinical practice.
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18
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Cernaro V, Calabrese V, Loddo S, Corsaro R, Macaione V, Ferlazzo VT, Cigala RM, Crea F, De Stefano C, Gembillo G, Romeo A, Longhitano E, Santoro D, Buemi M, Benvenga S. Indole-3-acetic acid correlates with monocyte-to-high-density lipoprotein (HDL) ratio (MHR) in chronic kidney disease patients. Int Urol Nephrol 2022; 54:2355-2364. [PMID: 35147839 DOI: 10.1007/s11255-022-03137-0] [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: 02/20/2021] [Accepted: 01/30/2022] [Indexed: 10/19/2022]
Abstract
PURPOSE Indole-3-acetic acid is a protein-bound indolic uremic toxin deriving from tryptophan metabolism. Increased levels are associated with higher thrombotic risk and both cardiovascular and all-cause mortality. An emerging biomarker of cardiovascular disease is the monocyte-to-high-density lipoprotein ratio (MHR). The main purpose of this study was to investigate the association of indole-3-acetic acid with MHR and other markers of cardiovascular risk in patients with chronic kidney disease (CKD). METHODS We enrolled 61 non-dialysis CKD patients and 6 dialysis patients. Indole-3-acetic acid levels were measured with ELISA technique. RESULTS In the whole cohort of 67 patients, indole-3-acetic acid was directly related to Ca × P (ρ = 0.256; P = 0.0365) and MHR (ρ = 0.321; P = 0.0082). In the 40 patients with previous cardiovascular events, indole-3-acetic acid correlated with uric acid (r = 0.3952; P = 0.0116) and MHR (ρ = 0.380; P = 0.0157). MHR was related with fibrinogen (ρ = 0.426; P = 0.0010), arterial hypertension (ρ = 0.274; P = 0.0251), C-reactive protein (ρ = 0.332; P = 0.0061), gender (ρ = - 0.375; P = 0.0017; 0 = male, 1 = female), and CKD stage (ρ = 0.260; P = 0.0337). A multiple regression analysis suggested that indole-3-acetic acid might be an independent predictor of MHR. CONCLUSION This study shows a significant association between indole-3-acetic acid and MHR. Prospective studies are required to evaluate if decreasing indole-3-acetic acid concentrations may reduce MHR levels and cardiovascular events and improve clinical outcomes.
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Affiliation(s)
- Valeria Cernaro
- Unit of Nephrology and Dialysis, Department of Clinical and Experimental Medicine, University of Messina, Via Consolare Valeria n. 1, 98124, Messina, Italy.
| | - Vincenzo Calabrese
- Unit of Nephrology and Dialysis, Department of Clinical and Experimental Medicine, University of Messina, Via Consolare Valeria n. 1, 98124, Messina, Italy
| | - Saverio Loddo
- Department of Clinical and Experimental Medicine, University of Messina, Messina, Italy
| | - Roberta Corsaro
- Department of Clinical and Experimental Medicine, University of Messina, Messina, Italy
| | - Vincenzo Macaione
- Department of Clinical and Experimental Medicine, University of Messina, Messina, Italy
| | | | - Rosalia Maria Cigala
- Department of Chemical, Biological, Pharmaceutical and Environmental Sciences, University of Messina, Messina, Italy
| | - Francesco Crea
- Department of Chemical, Biological, Pharmaceutical and Environmental Sciences, University of Messina, Messina, Italy
| | - Concetta De Stefano
- Department of Chemical, Biological, Pharmaceutical and Environmental Sciences, University of Messina, Messina, Italy
| | - Guido Gembillo
- Unit of Nephrology and Dialysis, Department of Clinical and Experimental Medicine, University of Messina, Via Consolare Valeria n. 1, 98124, Messina, Italy
| | - Adolfo Romeo
- Unit of Nephrology and Dialysis, Department of Clinical and Experimental Medicine, University of Messina, Via Consolare Valeria n. 1, 98124, Messina, Italy
| | - Elisa Longhitano
- Unit of Nephrology and Dialysis, Department of Clinical and Experimental Medicine, University of Messina, Via Consolare Valeria n. 1, 98124, Messina, Italy
| | - Domenico Santoro
- Unit of Nephrology and Dialysis, Department of Clinical and Experimental Medicine, University of Messina, Via Consolare Valeria n. 1, 98124, Messina, Italy
| | - Michele Buemi
- Unit of Nephrology and Dialysis, Department of Clinical and Experimental Medicine, University of Messina, Via Consolare Valeria n. 1, 98124, Messina, Italy
| | - Salvatore Benvenga
- Endocrinology, Department of Clinical and Experimental Medicine, University of Messina, Messina, Italy.,Master Program on Childhood, Adolescent and Women's Endocrine Health, University of Messina, Messina, Italy.,Interdepartmental Program of Molecular and Clinical Endocrinology, and Women's Endocrine Health, University Hospital, Policlinico Universitario G. Martino, Messina, Italy
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19
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Bowry SK, Kotanko P, Himmele R, Tao X, Anger M. The membrane perspective of uraemic toxins: which ones should, or can, be removed? Clin Kidney J 2021; 14:i17-i31. [PMID: 34987783 PMCID: PMC8711755 DOI: 10.1093/ckj/sfab202] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2021] [Indexed: 11/15/2022] Open
Abstract
Informed decision-making is paramount to the improvement of dialysis therapies and patient outcomes. A cornerstone of delivery of optimal dialysis therapy is to delineate which substances (uraemic retention solutes or 'uraemic toxins') contribute to the condition of uraemia in terms of deleterious biochemical effects they may exert. Thereafter, decisions can be made as to which of the accumulated compounds need to be targeted for removal and by which strategies. For haemodialysis (HD), the non-selectivity of membranes is sometimes considered a limitation. Yet, considering that dozens of substances with potential toxicity need to be eliminated, and targeting removal of individual toxins explicitly is not recommended, current dialysis membranes enable elimination of several molecules of a broad size range within a single therapy session. However, because HD solute removal is based on size-exclusion principles, i.e. the size of the substances to be removed relative to the mean size of the 'pores' of the membrane, only a limited degree of selectivity of removal is possible. Removal of unwanted substances during HD needs to be weighed against the unavoidable loss of substances that are recognized to be necessary for bodily functions and physiology. In striving to improve the efficiency of HD by increasing the porosity of membranes, there is a greater potential for the loss of substances that are of benefit. Based on this elementary trade-off and availability of recent guidance on the relative toxicity of substances retained in uraemia, we propose a new evidence-linked uraemic toxin elimination (ELUTE) approach whereby only those clusters of substances for which there is a sufficient body of evidence linking them to deleterious biological effects need to be targeted for removal. Our approach involves correlating the physical properties of retention solutes (deemed to express toxicity) with key determinants of membranes and separation processes. Our analysis revealed that in attempting to remove the relatively small number of 'larger' substances graded as having only moderate toxicity, uncontrolled (and efficient) removal of several useful compounds would take place simultaneously and may compromise the well-being or outcomes of patients. The bulk of the uraemic toxin load comprises uraemic toxins below <30 000 Da and are adequately removed by standard membranes. Further, removal of a few difficult-to-remove-by-dialysis (protein-bound) compounds that express toxicity cannot be achieved by manipulation of pore size alone. The trade-off between the benefits of effective removal of the bulk of the uraemic toxin load and risks (increased loss of useful substances) associated with targeting the removal of a few larger substances in 'high-efficiency' HD treatment strategies needs to be recognized and better understood. The removability during HD of substances, be they toxic, inert or beneficial, needs be revised to establish the pros and cons of current dialytic elimination strategies. .
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Affiliation(s)
- Sudhir K Bowry
- Dialysis-at-Crossroads (D@X) Advisory, Bad Nauheim, Germany
| | | | - Rainer Himmele
- Global Medical Information and Education, Fresenius Medical Care, Charlotte, NC, USA
| | - Xia Tao
- Renal Research Institute, New York, NY, USA
| | - Michael Anger
- Global Medical Office, Fresenius Medical Care, Waltham, MA, USA
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20
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Świerczyńska K, Białynicki-Birula R, Szepietowski JC. Chronic Intractable Pruritus in Chronic Kidney Disease Patients: Prevalence, Impact, and Management Challenges - A Narrative Review. Ther Clin Risk Manag 2021; 17:1267-1282. [PMID: 34876816 PMCID: PMC8643219 DOI: 10.2147/tcrm.s310550] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2021] [Accepted: 11/14/2021] [Indexed: 12/27/2022] Open
Abstract
Chronic kidney disease (CKD) is recognized as a leading public health problem and causes numerous health complications. One of the most common and burdensome dermatological symptoms affecting patients undergoing dialysis is CKD-associated pruritus (CKD-aP). This condition not only has a negative impact on sleep, mood, daily activities, and quality of life but also increases the mortality risk of hemodialyzed patients. Despite that, this condition is greatly underestimated in clinical practice. Due to the complex and still not fully understood etiopathogenesis of CKD-aP, the choice of an effective therapy remains a challenge for clinicians. Most common therapeutic algorithms use topical treatment, phototherapy, and various systemic approaches. This review aimed to summarize most recent theories about the pathogenesis, clinical features, and treatment of CKD-aP.
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Affiliation(s)
- Karolina Świerczyńska
- Department of Dermatology, Venereology and Allergology, Wroclaw Medical University, Wroclaw, Poland
| | - Rafał Białynicki-Birula
- Department of Dermatology, Venereology and Allergology, Wroclaw Medical University, Wroclaw, Poland
| | - Jacek C Szepietowski
- Department of Dermatology, Venereology and Allergology, Wroclaw Medical University, Wroclaw, Poland
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21
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Wee HN, Liu JJ, Ching J, Kovalik JP, Lim SC. The Kynurenine Pathway in Acute Kidney Injury and Chronic Kidney Disease. Am J Nephrol 2021; 52:771-787. [PMID: 34753140 PMCID: PMC8743908 DOI: 10.1159/000519811] [Citation(s) in RCA: 27] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2021] [Accepted: 09/15/2021] [Indexed: 12/12/2022]
Abstract
BACKGROUND The kynurenine pathway (KP) is the major catabolic pathway for tryptophan degradation. The KP plays an important role as the sole de novo nicotinamide adenine dinucleotide (NAD+) biosynthetic pathway in normal human physiology and functions as a counter-regulatory mechanism to mitigate immune responses during inflammation. Although the KP has been implicated in a variety of disorders including Huntington's disease, seizures, cardiovascular disease, and osteoporosis, its role in renal diseases is seldom discussed. SUMMARY This review summarizes the roles of the KP and its metabolites in acute kidney injury (AKI) and chronic kidney disease (CKD) based on current literature evidence. Metabolomics studies demonstrated that the KP metabolites were significantly altered in patients and animal models with AKI or CKD. The diagnostic and prognostic values of the KP metabolites in AKI and CKD were highlighted in cross-sectional and longitudinal human observational studies. The biological impact of the KP on the pathophysiology of AKI and CKD has been studied in experimental models of different etiologies. In particular, the activation of the KP was found to confer protection in animal models of glomerulonephritis, and its immunomodulatory mechanism may involve the regulation of T cell subsets such as Th17 and regulatory T cells. Manipulation of the KP to increase NAD+ production or diversion toward specific KP metabolites was also found to be beneficial in animal models of AKI. Key Messages: KP metabolites are reported to be dysregulated in human observational and animal experimental studies of AKI and CKD. In AKI, the magnitude and direction of changes in the KP depend on the etiology of the damage. In CKD, KP metabolites are altered with the onset and progression of CKD all the way to advanced stages of the disease, including uremia and its related vascular complications. The activation of the KP and diversion to specific sub-branches are currently being explored as therapeutic strategies in these diseases, especially with regards to the immunomodulatory effects of certain KP metabolites. Further elucidation of the KP may hold promise for the development of biomarkers and targeted therapies for these kidney diseases.
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Affiliation(s)
| | - Jian-Jun Liu
- Clinical Research Unit, Khoo Teck Puat Hospital, Singapore, Singapore
| | - Jianhong Ching
- Duke-NUS Medical School, Singapore, Singapore
- KK Research Centre, KK Women's and Children's Hospital, Singapore, Singapore
| | | | - Su Chi Lim
- Clinical Research Unit, Khoo Teck Puat Hospital, Singapore, Singapore
- Saw Swee Hock School of Public Health, National University of Singapore, Singapore, Singapore
- Diabetes Centre, Admiralty Medical Centre, Singapore, Singapore
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22
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Maheshwari V, Tao X, Thijssen S, Kotanko P. Removal of Protein-Bound Uremic Toxins Using Binding Competitors in Hemodialysis: A Narrative Review. Toxins (Basel) 2021; 13:toxins13090622. [PMID: 34564626 PMCID: PMC8473190 DOI: 10.3390/toxins13090622] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2021] [Revised: 08/28/2021] [Accepted: 08/31/2021] [Indexed: 11/16/2022] Open
Abstract
Removal of protein-bound uremic toxins (PBUTs) during conventional dialysis is insufficient. PBUTs are associated with comorbidities and mortality in dialysis patients. Albumin is the primary carrier for PBUTs and only a small free fraction of PBUTs are dialyzable. In the past, we proposed a novel method where a binding competitor is infused upstream of a dialyzer into an extracorporeal circuit. The competitor competes with PBUTs for their binding sites on albumin and increases the free PBUT fraction. Essentially, binding competitor-augmented hemodialysis is a reactive membrane separation technique and is a paradigm shift from conventional dialysis therapies. The proposed method has been tested in silico, ex vivo, and in vivo, and has proven to be very effective in all scenarios. In an ex vivo study and a proof-of-concept clinical study with 18 patients, ibuprofen was used as a binding competitor; however, chronic ibuprofen infusion may affect residual kidney function. Binding competition with free fatty acids significantly improved PBUT removal in pre-clinical rat models. Based on in silico analysis, tryptophan can also be used as a binding competitor; importantly, fatty acids or tryptophan may have salutary effects in HD patients. More chemoinformatics research, pre-clinical, and clinical studies are required to identify ideal binding competitors before routine clinical use.
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Affiliation(s)
- Vaibhav Maheshwari
- Renal Research Institute, New York, NY 10065, USA; (X.T.); (S.T.); (P.K.)
- Correspondence:
| | - Xia Tao
- Renal Research Institute, New York, NY 10065, USA; (X.T.); (S.T.); (P.K.)
| | - Stephan Thijssen
- Renal Research Institute, New York, NY 10065, USA; (X.T.); (S.T.); (P.K.)
| | - Peter Kotanko
- Renal Research Institute, New York, NY 10065, USA; (X.T.); (S.T.); (P.K.)
- Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
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23
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Saar-Kovrov V, Zidek W, Orth-Alampour S, Fliser D, Jankowski V, Biessen EAL, Jankowski J. Reduction of protein-bound uraemic toxins in plasma of chronic renal failure patients: A systematic review. J Intern Med 2021; 290:499-526. [PMID: 33792983 DOI: 10.1111/joim.13248] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/09/2020] [Revised: 12/07/2020] [Accepted: 12/16/2020] [Indexed: 12/23/2022]
Abstract
BACKGROUND Protein-bound uraemic toxins (PBUTs) accumulate in patients with chronic kidney disease and impose detrimental effects on the vascular system. However, a unanimous consensus on the most optimum approach for the reduction of plasma PBUTs is still lacking. METHODS In this systematic review, we aimed to identify the most efficient clinically available plasma PBUT reduction method reported in the literature between 1980 and 2020. The literature was screened for clinical studies describing approaches to reduce the plasma concentration of known uraemic toxins. There were no limits on the number of patients studied or on the duration or design of the studies. RESULTS Out of 1274 identified publications, 101 studies describing therapeutic options aiming at the reduction of PBUTs in CKD patients were included in this review. We stratified the studies by the PBUTs and the duration of the analysis into acute (data from a single procedure) and longitudinal (several treatment interventions) trials. Reduction ratio (RR) was used as the measure of plasma PBUTs lowering efficiency. For indoxyl sulphate and p-cresyl sulphate, the highest RR in the acute studies was demonstrated for fractionated plasma separation, adsorption and dialysis system. In the longitudinal trials, supplementation of haemodialysis patients with AST-120 (Kremezin®) adsorbent showed the highest RR. However, no superior method for the reduction of all types of PBUTs was identified based on the published studies. CONCLUSIONS Our study shows that there is presently no technique universally suitable for optimum reduction of all PBUTs. There is a clear need for further research in this field.
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Affiliation(s)
- V Saar-Kovrov
- From the, Institute for Molecular Cardiovascular Research IMCAR, University hospital, Aachen, Germany.,Experimental Vascular Pathology Group, Department of Pathology, Cardiovascular Research Institute Maastricht, Maastricht University Medical Center, Maastricht, the Netherlands
| | - W Zidek
- Department of Nephrology, Charité - Universitätsmedizin Berlin, Berlin, Germany
| | - S Orth-Alampour
- From the, Institute for Molecular Cardiovascular Research IMCAR, University hospital, Aachen, Germany
| | - D Fliser
- From the, Institute for Molecular Cardiovascular Research IMCAR, University hospital, Aachen, Germany.,Department of Internal Medicine IV - Nephrology and Hypertension, Saarland University Medical Center, Homburg, Germany
| | - V Jankowski
- From the, Institute for Molecular Cardiovascular Research IMCAR, University hospital, Aachen, Germany
| | - E A L Biessen
- From the, Institute for Molecular Cardiovascular Research IMCAR, University hospital, Aachen, Germany.,Experimental Vascular Pathology Group, Department of Pathology, Cardiovascular Research Institute Maastricht, Maastricht University Medical Center, Maastricht, the Netherlands
| | - J Jankowski
- From the, Institute for Molecular Cardiovascular Research IMCAR, University hospital, Aachen, Germany.,Department of Nephrology, Charité - Universitätsmedizin Berlin, Berlin, Germany
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24
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Chronic Kidney Disease-Associated Itch (CKD-aI) in Children-A Narrative Review. Toxins (Basel) 2021; 13:toxins13070450. [PMID: 34209560 PMCID: PMC8309841 DOI: 10.3390/toxins13070450] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2021] [Revised: 06/26/2021] [Accepted: 06/28/2021] [Indexed: 01/08/2023] Open
Abstract
Chronic kidney disease (CKD) is a condition of widespread epidemiology and serious consequences affecting all organs of the organism and associated with significant mortality. The knowledge on CKD is rapidly evolving, especially concerning adults. Recently, more data is also appearing regarding CKD in children. Chronic itch (CI) is a common symptom appearing due to various underlying dermatological and systemic conditions. CI may also appear in association with CKD and is termed chronic kidney disease-associated itch (CKD-aI). CKD-aI is relatively well-described in the literature concerning adults, yet it also affects children. Unfortunately, the data on paediatric CKD-aI is particularly scarce. This narrative review aims to describe various aspects of CKD-aI with an emphasis on children, based on the available data in this population and the data extrapolated from adults. Its pathogenesis is described in details, focusing on the growing role of uraemic toxins (UTs), as well as immune dysfunction, altered opioid transmission, infectious agents, xerosis, neuropathy and dialysis-associated aspects. Moreover, epidemiological and clinical aspects are reviewed based on the few data on CKD-aI in children, whereas treatment recommendations are proposed as well, based on the literature on CKD-aI in adults and own experience in managing CI in children.
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25
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Uremic Toxins and Their Relation with Oxidative Stress Induced in Patients with CKD. Int J Mol Sci 2021; 22:ijms22126196. [PMID: 34201270 PMCID: PMC8229520 DOI: 10.3390/ijms22126196] [Citation(s) in RCA: 26] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2021] [Revised: 05/28/2021] [Accepted: 06/05/2021] [Indexed: 12/15/2022] Open
Abstract
The presence of toxins is believed to be a major factor in the development of uremia in patients with chronic kidney disease (CKD) and end-stage renal disease (ESRD). Uremic toxins have been divided into 3 groups: small substances dissolved in water, medium molecules: peptides and low molecular weight proteins, and protein-bound toxins. One of the earliest known toxins is urea, the concentration of which was considered negligible in CKD patients. However, subsequent studies have shown that it can lead to increased production of reactive oxygen species (ROS), and induce insulin resistance in vitro and in vivo, as well as cause carbamylation of proteins, peptides, and amino acids. Other uremic toxins and their participation in the damage caused by oxidative stress to biological material are also presented. Macromolecules and molecules modified as a result of carbamylation, oxidative stress, and their adducts with uremic toxins, may lead to cardiovascular diseases, and increased risk of mortality in patients with CKD.
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26
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Hou YC, Huang CL, Lu CL, Zheng CM, Lin YF, Lu KC, Chung YL, Chen RM. The Role of Plasma Neurofilament Light Protein for Assessing Cognitive Impairment in Patients With End-Stage Renal Disease. Front Aging Neurosci 2021; 13:657794. [PMID: 34122041 PMCID: PMC8192845 DOI: 10.3389/fnagi.2021.657794] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2021] [Accepted: 05/03/2021] [Indexed: 12/26/2022] Open
Abstract
Introduction: End-stage renal disease (ESRD) is defined as the irreversible loss of renal function, necessitating renal replacement therapy. Patients with ESRD tend to have more risk factors for cognitive impairment than the general population, including hypertension, accumulative uremic toxin, anemia, and old age. The association between these risk factors and the pathologic protein was lacking. Blood-based assays for detecting pathologic protein, such as amyloid beta (Aβ), total tau protein, and neurofilament light chain (NfL), have the advantages of being less invasive and more cost-effective for diagnosing patients with cognitive impairment. The aim of the study is to validate if the common neurologic biomarkers were different in ESRD patients and to differentiate if the specific biomarkers could correlate with specific correctable risk factors. Methods: In total, 67 participants aged >45 years were enrolled. The definition of ESRD was receiving maintenance hemodialysis for >3 months. Cognitive impairment was defined as a Mini-Mental State Examination score of <24. The participants were divided into groups for ESRD with and without cognitive impairment. The blood-based biomarkers (tau protein, Aβ1/40, Aβ1/42, and NfL) were analyzed through immunomagnetic reduction assay. Other biochemical and hematologic data were obtained simultaneously. Summary of results: The study enrolled 43 patients with ESRD who did not have cognitive impairment and 24 patients with ESRD who had cognitive impairment [Mini-Mental State Examination (MMSE): 27.60 ± 1.80 vs. 16.84 ± 6.40, p < 0.05]. Among the blood-based biomarkers, NfL was marginally higher in the ESRD with cognitive impairment group than in the ESRD without cognitive impairment group (10.41 ± 3.26 vs. 8.74 ± 2.81 pg/mL, p = 0.037). The concentrations of tau protein, amyloid β 1/42, and amyloid β 1/40 (p = 0.504, 0.393, and 0.952, respectively) were similar between the two groups. The area under the curve of NfL to distinguish cognitively impaired and unimpaired ESRD patients was 0.687 (95% confidence interval: 0.548-0.825, p = 0.034). There was no correlation between the concentration of NfL and MMSE among total population (r = -0.153, p = 0.277), patients with (r = 0.137, p = 0.583) or without cognitive impairment (r = 0.155, p = 0.333). Conclusion: Patients with ESRD who had cognitive impairment had marginally higher plasma NfL concentrations. NfL concentration was not correlated with the biochemical parameters, total MMSE among total population or individual groups with or without cognitive impairment. The concentrations of Aβ1/40, Aβ1/42, and tau were similar between the groups.
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Affiliation(s)
- Yi-Chou Hou
- Graduate Institute of Clinical Medicine, College of Medicine, Taipei Medical University, Taipei, Taiwan.,Department of Internal Medicine, Cardinal Tien Hospital, New Taipei City, Taiwan.,School of Medicine, Fu Jen Catholic University, New Taipei City, Taiwan
| | - Chuen-Lin Huang
- Department of Medical Research, Cardinal Tien Hospital, New Taipei City, Taiwan.,Department of Physiology and Biophysics, National Defense Medical Center, Graduate Institute of Physiology, Taipei, Taiwan
| | - Chien-Lin Lu
- School of Medicine, Fu Jen Catholic University, New Taipei City, Taiwan.,Department of Nephrology, Fu Jen Catholic University Hospital, New Taipei City, Taiwan
| | - Cai-Mei Zheng
- Division of Nephrology, Department of Internal Medicine, Taipei Medical University Shuang Ho Hospital, New Taipei City, Taiwan.,Division of Nephrology, Department of Internal Medicine, School of Medicine, College of Medicine, Taipei Medical University, Taipei, Taiwan.,Taipei Medical University-Research Center of Urology and Kidney, Taipei Medical University, Taipei, Taiwan
| | - Yuh-Feng Lin
- Graduate Institute of Clinical Medicine, College of Medicine, Taipei Medical University, Taipei, Taiwan.,Division of Nephrology, Department of Internal Medicine, Taipei Medical University Shuang Ho Hospital, New Taipei City, Taiwan.,Division of Nephrology, Department of Internal Medicine, School of Medicine, College of Medicine, Taipei Medical University, Taipei, Taiwan.,Taipei Medical University-Research Center of Urology and Kidney, Taipei Medical University, Taipei, Taiwan.,National Defense Medical Center, Graduate Institute of Medical Sciences, Taipei, Taiwan
| | - Kuo-Cheng Lu
- Department of Nephrology, Taipei Tzu Chi Hospital, Buddhist Tzu Chi Medical Foundation, New Taipei City, Taiwan
| | - Ya-Lin Chung
- Department of Medical Laboratory, Cardinal-Tien Hospital, New Taipei City, Taiwan
| | - Ruei-Ming Chen
- TMU Research Center of Cancer Translational Medicine, Graduate Institute of Medical Sciences, College of Medicine, Taipei Medical University, Taipei, Taiwan.,Cell Physiology and Molecular Image Research Center, Wan Fang Hospital, Taipei Medical University, Taipei, Taiwan.,Anesthesiology and Health Policy Research Center, Taipei Medical University Hospital, Taipei, Taiwan
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27
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Magnani S, Atti M. Uremic Toxins and Blood Purification: A Review of Current Evidence and Future Perspectives. Toxins (Basel) 2021; 13:toxins13040246. [PMID: 33808345 PMCID: PMC8066023 DOI: 10.3390/toxins13040246] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2021] [Revised: 03/25/2021] [Accepted: 03/26/2021] [Indexed: 12/15/2022] Open
Abstract
Accumulation of uremic toxins represents one of the major contributors to the rapid progression of chronic kidney disease (CKD), especially in patients with end-stage renal disease that are undergoing dialysis treatment. In particular, protein-bound uremic toxins (PBUTs) seem to have an important key pathophysiologic role in CKD, inducing various cardiovascular complications. The removal of uremic toxins from the blood with dialytic techniques represents a proved approach to limit the CKD-related complications. However, conventional dialysis mainly focuses on the removal of water-soluble compounds of low and middle molecular weight, whereas PBTUs are strongly protein-bound, thus not efficiently eliminated. Therefore, over the years, dialysis techniques have been adapted by improving membranes structures or using combined strategies to maximize PBTUs removal and eventually prevent CKD-related complications. Recent findings showed that adsorption-based extracorporeal techniques, in addition to conventional dialysis treatment, may effectively adsorb a significant amount of PBTUs during the course of the sessions. This review is focused on the analysis of the current state of the art for blood purification strategies in order to highlight their potentialities and limits and identify the most feasible solution to improve toxins removal effectiveness, exploring possible future strategies and applications, such as the study of a synergic approach by reducing PBTUs production and increasing their blood clearance.
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28
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ter Beek O, van Gelder M, Lokhorst C, Hazenbrink D, Lentferink B, Gerritsen K, Stamatialis D. In vitro study of dual layer mixed matrix hollow fiber membranes for outside-in filtration of human blood plasma. Acta Biomater 2021; 123:244-253. [PMID: 33450414 DOI: 10.1016/j.actbio.2020.12.063] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2020] [Revised: 12/21/2020] [Accepted: 12/22/2020] [Indexed: 12/17/2022]
Abstract
Hemodialysis mainly removes small water-soluble uremic toxins but cannot effectively remove middle molecules and protein-bound uremic toxins. Besides, the therapy is intermittent leading to fluctuating blood values and fluid status which adversely impacts patients' health. Prolonged hemodialysis (with adequate anticoagulation) could improve the removal of toxins and the development of portable and wearable artificial kidneys could offer more flexibility in the dialysis scheme. This would enhance patients' overall health, autonomy, mobility and flexibility, allowing patients to participate in social and economic life. However, the time that patients' blood is exposed to the dialyzer material is longer during prolonged hemodialysis, and blood clots could obstruct the fiber lumen, resulting in a decrease of the effective membrane surface area available for toxin removal. The outside-in filtration (OIF) mode, wherein blood flows through the inter-fiber space instead of through the fiber lumina, has been applied widely in blood oxygenators to prevent fiber clotting, but not in hemodialysis. In this study, we present for the first time the development of a mixed matrix membrane (MMM) for OIF of human blood plasma. This MMM combines diffusion and adsorption and consists of a polymeric membrane matrix with activated carbon (AC) particles on the inside layer, and a polymeric particle-free layer on the outer fiber layer. Our results show that in vitro MMM fibers for OIF demonstrate superior removal of the protein-bound uremic toxins, indoxyl sulfate and hippuric acid, compared to both earlier MMM fibers designed for inside-out filtration mode and commercial high-flux fibers. STATEMENT OF SIGNIFICANCE: Current hemodialysis therapy cannot effectively remove protein-bound toxins. Prolonged hemodialysis could improve toxin removal. However, during prolonged hemodialysis, blood clots could obstruct the fiber lumen, resulting in decreased effective membrane surface area available for toxin removal. We have prepared, for the first time, dual layer mixed matrix hollow fiber membranes (MMM) for outside-in filtration (OIF). The OIF mode wherein blood would flow through the inter-fiber space instead of through the fiber lumina could prevent fiber clotting. Moreover, the MMMs combine diffusion and adsorption to improve (protein-bound) toxin removal. We believe that the new design of our MMM fibers is an important contribution concerning the development of artificial kidney systems and the improvement of the health and well-being of patients with renal failure.
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Inverted U-Curve Association between Serum Indoxyl Sulfate Levels and Cardiovascular Events in Patients on Chronic Hemodialysis. J Clin Med 2021; 10:jcm10040744. [PMID: 33668430 PMCID: PMC7917606 DOI: 10.3390/jcm10040744] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2020] [Revised: 01/26/2021] [Accepted: 02/10/2021] [Indexed: 01/12/2023] Open
Abstract
Background: Protein-bound uremic toxins are associated with cardiovascular disease and mortality in patients with chronic kidney disease. We investigated their association with clinical outcomes in patients undergoing chronic hemodialysis (CHD). Methods: A prospective cohort study was conducted on 86 Taiwanese patients undergoing CHD. The predictors were indoxyl sulfate and p-cresyl sulfate concentrations, with each analyzed as three tertiles. Outcomes were cardiovascular events and all-cause mortality. Results: During a 25-month follow up period, there were 23 cardiovascular events and seven all-cause mortality events. In the crude survival analysis, the second indoxyl sulfate tertile was shown to be a powerful predictor of cardiovascular events compared with the third tertile (hazard ratio (HR), 3.14; 95% confidence interval (CI), 1.10–8.94), and the first tertile was shown to have a poor but insignificant cardiovascular outcome (HR, 1.09; 95% CI, 0.30–4.00). Moreover, the predictive power of the second indoxyl sulfate tertile for cardiovascular events remained after adjustment for confounders (HR, 5.42; 95% CI, 1.67–17.60). Conclusions: An inverse U-curve relationship was observed between the total serum indoxyl sulfate level and cardiovascular events in our CHD patients. A large-scale study is needed to confirm this relationship.
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Glorieux G, Vanholder R, Van Biesen W, Pletinck A, Schepers E, Neirynck N, Speeckaert M, De Bacquer D, Verbeke F. Free p-cresyl sulfate shows the highest association with cardiovascular outcome in chronic kidney disease. Nephrol Dial Transplant 2021; 36:998-1005. [DOI: 10.1093/ndt/gfab004] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2020] [Indexed: 12/13/2022] Open
Abstract
Abstract
Background
Several protein-bound uraemic toxins (PBUTs) have been associated with cardiovascular (CV) and all-cause mortality in chronic kidney disease (CKD) but the degree to which this is the case per individual PBUT and the pathophysiological mechanism have only partially been unraveled.
Methods
We compared the prognostic value of both total and free concentrations of five PBUTs [p-cresyl sulfate (pCS), p-cresyl glucuronide, indoxyl sulfate, indole acetic acid and hippuric acid] in a cohort of 523 patients with non-dialysis CKD Stages G1–G5. Patients were followed prospectively for the occurrence of a fatal or non-fatal CV event as the primary endpoint and a number of other major complications as secondary endpoints. In addition, association with and the prognostic value of nine markers of endothelial activation/damage was compared.
Results
After a median follow-up of 5.5 years, 149 patients developed the primary endpoint. In multivariate Cox regression models adjusted for age, sex, systolic blood pressure, diabetes mellitus and estimated glomerular filtration rate, and corrected for multiple testing, only free pCS was associated with the primary endpoint {hazard ratio [HR]1.39 [95% confidence interval (CI) 1.14–1.71]; P = 0.0014}. Free pCS also correlated with a disintegrin and metalloproteinase with a thrombospondin type 1 motif, member 13 (r = −0.114, P < 0.05), angiopoietin-2 (ANGPT2) (r = 0.194, P < 0.001), matrix metallopeptidase 7 (MMP-7; (r = 0.238, P < 0.001) and syndecan 1 (r = 0.235, P < 0.001). Of these markers of endothelial activation/damage, ANGPT2 [HR 1.46 (95% CI 1.25–1.70); P < 0.0001] and MMP-7 [HR 1.31 (95% CI 1.08–1.59); P = 0.0056] were also predictive of the primary outcome.
Conclusions
Among PBUTs, free pCS shows the highest association with CV outcome in non-dialysed patients with CKD. Two markers of endothelial activation/damage that were significantly correlated with free pCS, ANGPT2 and MMP-7 were also associated with CV outcome. The hypothesis that free pCS exerts its CV toxic effects by an adverse effect on endothelial function deserves further exploration.
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Affiliation(s)
- Griet Glorieux
- Department of Internal Medicine and Pediatrics, Nephrology Section, Ghent University Hospital, Ghent, Belgium
| | - Raymond Vanholder
- Department of Internal Medicine and Pediatrics, Nephrology Section, Ghent University Hospital, Ghent, Belgium
| | - Wim Van Biesen
- Department of Internal Medicine and Pediatrics, Nephrology Section, Ghent University Hospital, Ghent, Belgium
| | - Anneleen Pletinck
- Department of Internal Medicine and Pediatrics, Nephrology Section, Ghent University Hospital, Ghent, Belgium
| | - Eva Schepers
- Department of Internal Medicine and Pediatrics, Nephrology Section, Ghent University Hospital, Ghent, Belgium
| | - Nathalie Neirynck
- Department of Internal Medicine and Pediatrics, Nephrology Section, Ghent University Hospital, Ghent, Belgium
| | - Marijn Speeckaert
- Department of Internal Medicine and Pediatrics, Nephrology Section, Ghent University Hospital, Ghent, Belgium
| | - Dirk De Bacquer
- Department of Public Health and Primary Care, Ghent University, Ghent, Belgium
| | - Francis Verbeke
- Department of Internal Medicine and Pediatrics, Nephrology Section, Ghent University Hospital, Ghent, Belgium
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Daneshamouz S, Eduok U, Abdelrasoul A, Shoker A. Protein-bound uremic toxins (PBUTs) in chronic kidney disease (CKD) patients: Production pathway, challenges and recent advances in renal PBUTs clearance. NANOIMPACT 2021; 21:100299. [PMID: 35559786 DOI: 10.1016/j.impact.2021.100299] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/26/2020] [Revised: 01/13/2021] [Accepted: 01/20/2021] [Indexed: 06/15/2023]
Abstract
Uremic toxins, a group of uremic retention solutes with high concentration which their accumulation on the body makes several biological problems, have recently gained a large interest. The importance of this issue more targets patients with compromised kidney function since the presence of these toxins in their bodies contributes to serious illness and death. It is reported that around 14% of people are subjected of CKD's problems. Among different classifications of uremic toxins, protein bound uremic toxins are poorly removed from the body as they tightly bind to proteins like serum albumin. A deeper and closer understanding of methods for removing protein bound uremic toxins and their efficiency is of paramount importance. This article discussed the most critical protein bound uremic toxins from different points of view including their chemistry, binding sites, interactions, and their biological impacts. Concerning the toxicity and high concentration, p-cresyl sulfate (PCS), Indoxyl sulfate (IS), 3-Carboxy-4-methyl-5-propyl-2-furanpropionic acid (CMPF), and Indole- 3-acetic acid (IAA) was chosen to study in this article. Results offered that the functional groups of mentioned PBUTs and the way that they interact with the adsorbent play an important role in finding substances for removal of them. Furthermore, the development of nanoparticle (NPs) for promising biomedical purposes has been explored. However, there is still a need for further investigation to find biocompatible substances focusing on the removal of PBUTs. PBUTs are a unique class of uremic toxins whose renal clearance mechanisms and role in uremic pathophysiology are still unclear. This review outlines the biochemical aspects of PBUT/protein binding in a view to explaining their renal formation to elimination mechanisms; some examples are drawn from routes involving albumin-binding with indoxyl sulphate, p-cresyl sulfate, p-cresyl glucuronide and hippuric acid. We have also highlighted the kinetic behaviors during dialytic removal of PBUTs to address future concerns regarding dialytic therapy.
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Affiliation(s)
- Sana Daneshamouz
- Department of Chemical and Biological Engineering, University of Saskatchewan, 57 Campus Drive, Saskatoon, Saskatchewan S7N 5A9, Canada
| | - Ubong Eduok
- Department of Chemical and Biological Engineering, University of Saskatchewan, 57 Campus Drive, Saskatoon, Saskatchewan S7N 5A9, Canada
| | - Amira Abdelrasoul
- Department of Chemical and Biological Engineering, University of Saskatchewan, 57 Campus Drive, Saskatoon, Saskatchewan S7N 5A9, Canada; Department of Biomedical Engineering, University of Saskatchewan, 57 Campus Drive, Saskatoon, Saskatchewan S7N 5A9, Canada.
| | - Ahmed Shoker
- Nephrology Division, College of Medicine, University of Saskatchewan, 107 Wiggins Rd, Saskatoon, SK S7N 5E5, Canada; Saskatchewan Transplant Program, St. Paul's Hospital, 1702 20th Street West Saskatoon Saskatchewan S7M 0Z9, Canada
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How do Uremic Toxins Affect the Endothelium? Toxins (Basel) 2020; 12:toxins12060412. [PMID: 32575762 PMCID: PMC7354502 DOI: 10.3390/toxins12060412] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2020] [Revised: 06/15/2020] [Accepted: 06/19/2020] [Indexed: 12/11/2022] Open
Abstract
Uremic toxins can induce endothelial dysfunction in patients with chronic kidney disease (CKD). Indeed, the structure of the endothelial monolayer is damaged in CKD, and studies have shown that the uremic toxins contribute to the loss of cell–cell junctions, increasing permeability. Membrane proteins, such as transporters and receptors, can mediate the interaction between uremic toxins and endothelial cells. In these cells, uremic toxins induce oxidative stress and activation of signaling pathways, including the aryl hydrocarbon receptor (AhR), nuclear factor kappa B (NF-κB), and mitogen-activated protein kinase (MAPK) pathways. The activation of these pathways leads to overexpression of proinflammatory (e.g., monocyte chemoattractant protein-1, E-selectin) and prothrombotic (e.g., tissue factor) proteins. Uremic toxins also induce the formation of endothelial microparticles (EMPs), which can lead to the activation and dysfunction of other cells, and modulate the expression of microRNAs that have an important role in the regulation of cellular processes. The resulting endothelial dysfunction contributes to the pathogenesis of cardiovascular diseases, such as atherosclerosis and thrombotic events. Therefore, uremic toxins as well as the pathways they modulated may be potential targets for therapies in order to improve treatment for patients with CKD.
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