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Pantazi AC, Kassim MAK, Nori W, Tuta LA, Mihai CM, Chisnoiu T, Balasa AL, Mihai L, Lupu A, Frecus CE, Lupu VV, Chirila SI, Badescu AG, Hangan LT, Cambrea SC. Clinical Perspectives of Gut Microbiota in Patients with Chronic Kidney Disease and End-Stage Kidney Disease: Where Do We Stand? Biomedicines 2023; 11:2480. [PMID: 37760920 PMCID: PMC10525496 DOI: 10.3390/biomedicines11092480] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2023] [Revised: 08/26/2023] [Accepted: 09/05/2023] [Indexed: 09/29/2023] Open
Abstract
The gut microbiota (GM) plays a vital role in human health, with increasing evidence linking its imbalance to chronic kidney disease and end-stage kidney disease. Although the exact methods underlying kidney-GM crosstalk are not fully understood, interventions targeting GM were made and lay in three aspects: diagnostic, predictive, and therapeutic interventions. While these interventions show promising results in reducing uremic toxins and inflammation, challenges remain in the form of patient-specific GM variability, potential side effects, and safety concerns. Our understanding of GMs role in kidney disease is still evolving, necessitating further research to elucidate the causal relationship and mechanistic interactions. Personalized interventions focusing on specific GM signatures could enhance patient outcomes. However, comprehensive clinical trials are needed to validate these approaches' safety, efficacy, and feasibility.
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Affiliation(s)
| | | | - Wassan Nori
- College of Medicine, Mustansiriyah University, Baghdad 10052, Iraq;
| | - Liliana Ana Tuta
- Faculty of Medicine, “Ovidius” University of Constanta, 900470 Constanta, Romania (L.A.T.)
- Clinical Emergency Hospital of Constanta, 900591 Constanta, Romania
| | - Cristina Maria Mihai
- Faculty of Medicine, “Ovidius” University of Constanta, 900470 Constanta, Romania (L.A.T.)
- Clinical Emergency Hospital of Constanta, 900591 Constanta, Romania
| | - Tatiana Chisnoiu
- Faculty of Medicine, “Ovidius” University of Constanta, 900470 Constanta, Romania (L.A.T.)
- Clinical Emergency Hospital of Constanta, 900591 Constanta, Romania
| | - Adriana Luminita Balasa
- Faculty of Medicine, “Ovidius” University of Constanta, 900470 Constanta, Romania (L.A.T.)
- Clinical Emergency Hospital of Constanta, 900591 Constanta, Romania
| | - Larisia Mihai
- Faculty of Medicine, “Ovidius” University of Constanta, 900470 Constanta, Romania (L.A.T.)
- Clinical Emergency Hospital of Constanta, 900591 Constanta, Romania
| | - Ancuta Lupu
- Faculty of Medicine, “Grigore T. Popa” University of Medicine and Pharmacy, 700115 Iasi, Romania;
| | - Corina Elena Frecus
- Faculty of Medicine, “Ovidius” University of Constanta, 900470 Constanta, Romania (L.A.T.)
- Clinical Emergency Hospital of Constanta, 900591 Constanta, Romania
| | - Vasile Valeriu Lupu
- Faculty of Medicine, “Grigore T. Popa” University of Medicine and Pharmacy, 700115 Iasi, Romania;
| | - Sergiu Ioachim Chirila
- Faculty of Medicine, “Ovidius” University of Constanta, 900470 Constanta, Romania (L.A.T.)
| | | | - Laurentiu-Tony Hangan
- Faculty of Medicine, “Ovidius” University of Constanta, 900470 Constanta, Romania (L.A.T.)
| | - Simona Claudia Cambrea
- Faculty of Medicine, “Ovidius” University of Constanta, 900470 Constanta, Romania (L.A.T.)
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Rodrigues FG, Ormanji MS, Heilberg IP, Bakker SJL, de Borst MH. Interplay between gut microbiota, bone health and vascular calcification in chronic kidney disease. Eur J Clin Invest 2021; 51:e13588. [PMID: 33948936 PMCID: PMC8459296 DOI: 10.1111/eci.13588] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/07/2021] [Revised: 04/30/2021] [Accepted: 05/01/2021] [Indexed: 02/06/2023]
Abstract
Deregulations in gut microbiota may play a role in vascular and bone disease in chronic kidney disease (CKD). As glomerular filtration rate declines, the colon becomes more important as a site of excretion of urea and uric acid, and an increased bacterial proteolytic fermentation alters the gut microbial balance. A diet with limited amounts of fibre, as well as certain medications (eg phosphate binders, iron supplementation, antibiotics) further contribute to changes in gut microbiota composition among CKD patients. At the same time, both vascular calcification and bone disease are common in patients with advanced kidney disease. This narrative review describes emerging evidence on gut dysbiosis, vascular calcification, bone demineralization and their interrelationship termed the 'gut-bone-vascular axis' in progressive CKD. The role of diet, gut microbial metabolites (ie indoxyl sulphate, p-cresyl sulphate, trimethylamine N-oxide (TMAO) and short-chain fatty acids (SCFA)), vitamin K deficiency, inflammatory cytokines and their impact on both bone health and vascular calcification are discussed. This framework may open up novel preventive and therapeutic approaches targeting the microbiome in an attempt to improve cardiovascular and bone health in CKD.
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Affiliation(s)
- Fernanda G Rodrigues
- Department of Nephrology, University of Groningen, University Medical Center Groningen, Groningen, the Netherlands.,Nutrition Post-Graduation Program, Universidade Federal de São Paulo, São Paulo, Brazil
| | - Milene S Ormanji
- Nephrology Division, Universidade Federal de São Paulo, São Paulo, Brazil
| | - Ita P Heilberg
- Nutrition Post-Graduation Program, Universidade Federal de São Paulo, São Paulo, Brazil.,Nephrology Division, Universidade Federal de São Paulo, São Paulo, Brazil
| | - Stephan J L Bakker
- Department of Nephrology, University of Groningen, University Medical Center Groningen, Groningen, the Netherlands
| | - Martin H de Borst
- Department of Nephrology, University of Groningen, University Medical Center Groningen, Groningen, the Netherlands
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Kim SM, Song IH. The clinical impact of gut microbiota in chronic kidney disease. Korean J Intern Med 2020; 35:1305-1316. [PMID: 32872729 PMCID: PMC7652652 DOI: 10.3904/kjim.2020.411] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/10/2020] [Accepted: 09/07/2020] [Indexed: 02/07/2023] Open
Abstract
Gut microorganisms play critical roles in both maintaining host homeostasis and the development of diverse diseases. Gut dysbiosis, an alteration of the composition and function of gut microorganisms, is commonly seen in patients with chronic kidney disease (CKD). CKD itself contributes to a disruption of the symbiotic relationship between the gut microbiota and the host, while the resulting gut dysbiosis may play a part in stage progression of CKD. This bidirectional relationship supports the concept that the gut microbiota is considered a novel focus for the pathogenesis and management of CKD. This article examines the interaction between the gut microbiota and the kidney, the mutual effects of dysbiosis and CKD, and possible treatment options to restore gut eubiosis, and reduce CKD progression and its related complications.
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Affiliation(s)
- So Mi Kim
- Division of Nephrology, Department of Internal Medicine, Dankook University Hospital, Cheonan, Korea
| | - Il han Song
- Division of Hepatology, Department of Internal Medicine, Dankook University Hospital, Cheonan, Korea
- Correspondence to Il Han Song, M.D. Division of Hepatology, Department of Internal Medicine, Dankook University Hospital, 201 Manghyang-ro, Dongnam-gu, Cheonan 31116, Korea Tel: +82-41-550-3924 Fax: +82-41-556-3256 E-mail:
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Parathyroid Hormone: A Uremic Toxin. Toxins (Basel) 2020; 12:toxins12030189. [PMID: 32192220 PMCID: PMC7150960 DOI: 10.3390/toxins12030189] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2020] [Revised: 03/08/2020] [Accepted: 03/08/2020] [Indexed: 12/27/2022] Open
Abstract
Parathyroid hormone (PTH) has an important role in the maintenance of serum calcium levels. It activates renal 1α-hydroxylase and increases the synthesis of the active form of vitamin D (1,25[OH]2D3). PTH promotes calcium release from the bone and enhances tubular calcium resorption through direct action on these sites. Hallmarks of secondary hyperparathyroidism associated with chronic kidney disease (CKD) include increase in serum fibroblast growth factor 23 (FGF-23), reduction in renal 1,25[OH]2D3 production with a decline in its serum levels, decrease in intestinal calcium absorption, and, at later stages, hyperphosphatemia and high levels of PTH. In this paper, we aim to critically discuss severe CKD-related hyperparathyroidism, in which PTH, through calcium-dependent and -independent mechanisms, leads to harmful effects and manifestations of the uremic syndrome, such as bone loss, skin and soft tissue calcification, cardiomyopathy, immunodeficiency, impairment of erythropoiesis, increase of energy expenditure, and muscle weakness.
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Veldeman L, Vanmassenhove J, Van Biesen W, Massy ZA, Liabeuf S, Glorieux G, Vanholder R. Evolution of protein-bound uremic toxins indoxyl sulphate and p-cresyl sulphate in acute kidney injury. Int Urol Nephrol 2019; 51:293-302. [PMID: 30604232 DOI: 10.1007/s11255-018-2056-x] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2018] [Accepted: 12/10/2018] [Indexed: 01/05/2023]
Abstract
BACKGROUND There is a gradual increase in serum concentrations of protein-bound colon-derived uremic toxins indoxyl sulphate (IxS) and p-cresyl sulphate (pCS) as chronic kidney disease (CKD) progresses. In acute kidney injury (AKI), up till now, the retention pattern has not been studied. METHODS In this study, 194 adult patients admitted with sepsis to the intensive care unit were included. IxS, pCS and serum creatinine (sCrea) were quantified at inclusion (D0) and at day 4, unless follow-up ended earlier (Dend). RESULTS Serum levels of sCrea (P < 0.001), IxS (P < 0.001) and pCS (P < 0.05) were higher in patients with AKI according to RIFLE classification at D0. In contrast with sCrea, IxS and pCS levels only increased from stage I (IxS) and F (pCS) on. When grouped according to evolution in RIFLE class from D0 to Dend, all solute concentrations were higher (P < 0.001) in the group with unfavourable evolution. In this group, there was a marked rise in sCrea (P < 0.001), a moderate one for pCS (P < 0.05), but no change for IxS (P = 0.112). There was a decrease (P < 0.001) of all solute concentrations in the group with favourable evolution. Comparing AKI with CKD patients matched for sCrea, total levels of both IxS and pCS were higher (P < 0.01) in patients with CKD. CONCLUSIONS Although concentrations of IxS and pCS both tend to rise in sepsis patients with AKI, their evolution does not conform with that of sCrea. For the same level of sCrea, IxS and pCS concentrations are lower in AKI compared with CKD.
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Affiliation(s)
- Laurens Veldeman
- Nephrology Division, Ghent University Hospital, Corneel Heymanslaan 10, 9000, Ghent, Belgium.
| | - Jill Vanmassenhove
- Nephrology Division, Ghent University Hospital, Corneel Heymanslaan 10, 9000, Ghent, Belgium
| | - Wim Van Biesen
- Nephrology Division, Ghent University Hospital, Corneel Heymanslaan 10, 9000, Ghent, Belgium
| | - Ziad A Massy
- Nephrology Division, Ambroise Paré Hospital, APHP, and Paris Ile de France West (UVSQ) University, Boulogne Billancourt, France.,Inserm U1018 Team5, UVSQ, University Paris, Saclay Villejuif, France
| | - Sophie Liabeuf
- Division of Clinical Pharmacology, Amiens University Hospital, Amiens, France
| | - Griet Glorieux
- Nephrology Division, Ghent University Hospital, Corneel Heymanslaan 10, 9000, Ghent, Belgium
| | - Raymond Vanholder
- Nephrology Division, Ghent University Hospital, Corneel Heymanslaan 10, 9000, Ghent, Belgium
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Role of Uremic Toxins for Kidney, Cardiovascular, and Bone Dysfunction. Toxins (Basel) 2018; 10:toxins10050202. [PMID: 29772660 PMCID: PMC5983258 DOI: 10.3390/toxins10050202] [Citation(s) in RCA: 75] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2018] [Revised: 05/04/2018] [Accepted: 05/10/2018] [Indexed: 02/07/2023] Open
Abstract
With decreasing kidney function, cardiovascular disease (CVD) and mineral bone disorders frequently emerge in patients with chronic kidney disease (CKD). For these patients, in addition to the traditional risk factors, non-traditional CKD-specific risk factors are also associated with such diseases and conditions. One of these non-traditional risk factors is the accumulation of uremic toxins (UTs). In addition, the accumulation of UTs further deteriorates kidney function. Recently, a huge number of UTs have been identified. Although many experimental and clinical studies have reported associations between UTs and the progression of CKD, CVD, and bone disease, these relationships are very complex and have not been fully elucidated. Among the UTs, indoxyl sulfate, asymmetric dimethylarginine, and p-cresylsulfate have been of particular focus, up until now. In this review, we summarize the pathophysiological influences of these UTs on the kidney, cardiovascular system, and bone, and discuss the clinical data regarding the harmful effects of these UTs on diseases and conditions.
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Barreto FC, Barreto DV, Stinghen AEM, Massy ZA. Comment on Indoxyl Sulfate-Review of Toxicity and Therapeutic Strategies. Toxins 2016, 8, 358. Toxins (Basel) 2017; 9:toxins9040142. [PMID: 28420181 PMCID: PMC5408216 DOI: 10.3390/toxins9040142] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2017] [Revised: 03/19/2017] [Accepted: 04/11/2017] [Indexed: 01/30/2023] Open
Abstract
Recently, the clinical and experimental evidences that support the toxic effects of indoxyl sulfate, a protein-bound uremic toxin in chronic kidney disease (CKD) patients, has been discussed. In this panorama, the authors described several in vitro and in vivo studies, suggesting that indoxyl sulfate may play a part in the pathogenesis of low turnover bone disease. However, the discussion claims the need for relevant clinical studies in CKD patients whose bone turnover biomarkers and bone histomorphometry were assessed in order to demonstrate the association between serum levels of indoxyl sulfate and bone turnover. We would like to underline the availability of this clinical data to support the concept that indoxyl sulfate may play a part in the pathogenesis of low turnover bone disease in CKD patients.
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Affiliation(s)
- Fellype C Barreto
- Division of Nephrology, Department of Internal Medicine, Federal University of Paraná, 80060-900 Curitiba, Brazil.
| | - Daniela V Barreto
- Division of Nephrology, Department of Internal Medicine, Federal University of Paraná, 80060-900 Curitiba, Brazil.
| | - Andrea E M Stinghen
- Experimental Nephrology Laboratory, Basic Pathology Department, Federal University of Paraná, 81531-980 Curitiba, Brazil.
| | - Ziad A Massy
- Division of Nephrology, Ambroise Paré University Hospital, APHP, Boulogne-Billancourt, Paris 92104, France.
- INSERM Unit 1018, CESP, University of Versailles-Saint-Quentin-en-Yvelines, University Paris-Saclay, 54500 Villejuif, France.
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Hirata J, Hirai K, Asai H, Matsumoto C, Inada M, Miyaura C, Yamato H, Watanabe-Akanuma M. Indoxyl sulfate exacerbates low bone turnover induced by parathyroidectomy in young adult rats. Bone 2015; 79:252-8. [PMID: 26112820 DOI: 10.1016/j.bone.2015.06.010] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/01/2014] [Revised: 05/29/2015] [Accepted: 06/16/2015] [Indexed: 11/17/2022]
Abstract
Low-turnover bone disease is one of the bone abnormalities observed in patients with chronic kidney disease (CKD) and is recognized to be associated with low serum parathyroid hormone (PTH) level and skeletal resistance to PTH. Indoxyl sulfate (IS) is a representative uremic toxin that accumulates in the blood as renal dysfunction progresses in CKD patients. A recent in vitro study using an osteoblastic cell culture system suggests that IS has an important role in the pathogenesis of low bone turnover through induction of skeletal resistance to PTH. However, the effects of IS on the progression of low bone turnover have not been elucidated. In the present study, we produced rats with low bone turnover by performing parathyroidectomy (PTX) and fed these rats a diet containing indole, a precursor of IS, to elevate blood IS level from indole metabolism. Bone metabolism was evaluated by measuring histomorphometric parameters of secondary spongiosa of the femur. Histomorphometric analyses revealed significant decreases in both bone formation-related parameters and bone resorption-related parameters in PTX rats. In indole-treated PTX rats, further decreases in bone formation-related parameters were observed. In addition, serum alkaline phosphatase activity, a bone formation marker, and bone mineral density of the tibia tended to decrease in indole-treated PTX rats. These findings strongly suggest that IS exacerbates low bone turnover through inhibition of bone formation by mechanisms unrelated to skeletal resistance to PTH.
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Affiliation(s)
- Junya Hirata
- Safety Research Center, Kureha Corporation, Tokyo 169-8503, Japan; Cooperative Major in Advanced Health Science, Tokyo University of Agriculture and Technology, Tokyo 184-8588, Japan.
| | - Kazuya Hirai
- Safety Research Center, Kureha Corporation, Tokyo 169-8503, Japan
| | - Hirobumi Asai
- Safety Research Center, Kureha Corporation, Tokyo 169-8503, Japan
| | - Chiho Matsumoto
- Cooperative Major in Advanced Health Science, Tokyo University of Agriculture and Technology, Tokyo 184-8588, Japan
| | - Masaki Inada
- Cooperative Major in Advanced Health Science, Tokyo University of Agriculture and Technology, Tokyo 184-8588, Japan
| | - Chisato Miyaura
- Cooperative Major in Advanced Health Science, Tokyo University of Agriculture and Technology, Tokyo 184-8588, Japan
| | - Hideyuki Yamato
- Safety Research Center, Kureha Corporation, Tokyo 169-8503, Japan
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Black AP, Cardozo LFMF, Mafra D. Effects of Uremic Toxins from the Gut Microbiota on Bone: A Brief Look at Chronic Kidney Disease. Ther Apher Dial 2015; 19:436-40. [PMID: 25944654 DOI: 10.1111/1744-9987.12307] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
Patients with chronic kidney disease (CKD) frequently have mineral and bone disorders (CKD-MBD) that are caused by several mechanisms. Recent research has suggested that uremic toxins from the gut such as p-cresyl sulfate (PCS) and indoxyl sulfate (IS) could also be involved in the development of bone disease in patients with CKD. IS and PCS are produced by microbiota in the gut, carried into the plasma bound to serum albumin, and are normally excreted into the urine. However, in patients with CKD, there is an accumulation of high levels of these uremic toxins. The exact mechanisms of action of uremic toxins in bone disease remain unclear. The purpose of this brief review is to discuss the link between uremic toxins (IS and PCS) and bone mineral disease in chronic kidney disease.
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Affiliation(s)
- Ana Paula Black
- Graduate Program in Medical Sciences, Universidade Federal Fluminense (UFF), Niterói-RJ, Brazil
| | - Ludmila F M F Cardozo
- Graduate Program in Cardiovascular Sciences, Universidade Federal Fluminense (UFF), Niterói-RJ, Brazil
| | - Denise Mafra
- Graduate Program in Medical Sciences, Universidade Federal Fluminense (UFF), Niterói-RJ, Brazil.,Graduate Program in Cardiovascular Sciences, Universidade Federal Fluminense (UFF), Niterói-RJ, Brazil
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10
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Association of Indoxyl Sulfate With Fibroblast Growth Factor 23 in Patients With Advanced Chronic Kidney Disease. Am J Med Sci 2014; 347:370-6. [DOI: 10.1097/maj.0b013e3182989f26] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
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Kim YH, Kwak KA, Gil HW, Song HY, Hong SY. Indoxyl sulfate promotes apoptosis in cultured osteoblast cells. BMC Pharmacol Toxicol 2013; 14:60. [PMID: 24289746 PMCID: PMC4222141 DOI: 10.1186/2050-6511-14-60] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2013] [Accepted: 11/27/2013] [Indexed: 02/08/2023] Open
Abstract
Background Indoxyl sulfate (IS), an organic anion uremic toxin, promotes the progression of renal dysfunction. Some studies have suggested that IS inhibits osteoclast differentiation and suppresses parathyroid hormone (PTH)-stimulated intracellular cAMP production, decreases PTH receptor expression, and induces oxidative stress in primary mouse calvaria osteoblast cell culture. However, the direct effects of IS on osteoblast apoptosis have not been fully evaluated. Hence, we investigated whether IS acts as a bone toxin by studying whether IS induces apoptosis and inhibits differentiation in the cultured osteoblast cell line MC3T3-E1. Methods We assessed the direct effect of IS on osteoblast differentiation and apoptosis in the MC3T3-E1 cell line. We examined caspase-3/7 activity, apoptosis-related proteins, free radical production, alkaline phosphatase activity, and mRNA expression of type 1 collagen and osteonectin. Furthermore, we investigated the uptake of IS via organic anion transport (OAT). Results We found that IS increased caspase activity and induced apoptosis. Production of free radicals increased depending on the concentration of IS. Furthermore, IS inhibited the expression of mRNA type 1 collagen and osteonectin and alkaline phosphatase activity. The expression of OAT, which is known to mediate the cellular uptake of IS, was detected in in the MC3T3-E1 cell line. The inhibition of OAT improved cell viability and suppressed the production of reactive oxygen species. These results suggest that IS is transported in MC3T3-E1 cells via OAT, which causes oxidative stress to inhibit osteoblast differentiation. Conclusions IS acts as a bone toxin by inhibiting osteoblast differentiation and inducing apoptosis.
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Affiliation(s)
| | | | - Hyo-Wook Gil
- Department of Internal Medicine, Soonchunhyang University Cheonan Hospital, 31 Soonchunhyang 6gil, Dongnam-gu, Cheonan, Chungnam 330-721, Korea.
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Abstract
INTRODUCTION Protein-bound uremic toxins such as indoxyl sulfate cannot be removed efficiently by hemodialysis. These protein-bound uremic toxins have emerged as important risk factors for the progression of chronic kidney disease (CKD) as well as cardiovascular disease (CVD). AREAS COVERED Indoxyl sulfate shows toxic effects on a variety of cells such as renal proximal tubular cells, glomerular mesangial cells, vascular smooth muscle cells, vascular endothelial cells, cardiomyocytes, cardiac fibroblasts, monocytes, osteoblasts and osteoclasts. This review overviews the cellular toxicity of indoxyl sulfate, its molecular mechanism and its role in the progression of CKD and CVD. Further, this review summarizes the clinical effects of AST-120 and the other strategies to reduce serum levels of indoxyl sulfate. EXPERT OPINION Protein-bound uremic toxins such as indoxyl sulfate have emerged as target molecules for therapeutic intervention of not only CKD but also CVD. An oral sorbent AST-120 reduces serum level of indoxyl sulfate by adsorbing indole in the intestine. The modulation of intestinal bacteria by prebiotics/probiotics might be effective in reducing the production of indole in the intestine followed by reduced serum levels of indoxyl sulfate. An alternative approach might be antagonist which can counteract indoxyl sulfate-induced cellular effects and signaling pathways.
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Affiliation(s)
- Toshimitsu Niwa
- Nagoya University Graduate School of Medicine, Department of Advanced Medicine for Uremia , 65 Tsurumai-cho, Showa-ku, Nagoya 466-8550 , Japan +81 52 744 1980 ; +81 52 744 1954 ;
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Nakano C, Hamano T, Fujii N, Obi Y, Matsui I, Tomida K, Mikami S, Inoue K, Shimomura A, Nagasawa Y, Okada N, Tsubakihara Y, Rakugi H, Isaka Y. Intact fibroblast growth factor 23 levels predict incident cardiovascular event before but not after the start of dialysis. Bone 2012; 50:1266-74. [PMID: 22425694 DOI: 10.1016/j.bone.2012.02.634] [Citation(s) in RCA: 62] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/27/2011] [Revised: 01/10/2012] [Accepted: 02/27/2012] [Indexed: 12/13/2022]
Abstract
PURPOSE Low 25-hydroxyvitamin D (25D), increased levels of fibroblast growth factor 23 (FGF23), parathyroid hormone (PTH), and alkaline phosphatase (ALP) were reported to be risk factors for mortality in chronic kidney disease (CKD). However, the independent associations of these factors with cardiovascular disease (CVD), the leading cause of death among CKD patients, remain unclear. Our purpose was to identify which of these factors predict incident CVD in CKD. METHODS In this prospective cohort study, we enrolled 738 predialysis outpatients in the two nephrology departments. We employed Cox proportional hazards analyses to elucidate predictors of the endpoint, defined as fatal or non-fatal cardiovascular event requiring hospitalization. Multiple imputation was performed for missing values. RESULTS Mean estimated glomerular filtration rate (eGFR) was 35 mL/min/1.73 m(2). During a median duration of 4.4 years, 86 patients developed the endpoint, of whom 62 patients achieved it before the initiation of dialysis. Multivariable analyses revealed that high serum intact FGF23 levels predicted the outcome preceding dialysis initiation (hazard ratio (HR) per lnFGF23 (SD), 1.64 (1.27-2.30)), while 25D, PTH, and bone-specific ALP did not. Adding FGF23 to the conventional model of age, sex, diabetes, prior CVD, pulse pressure, and eGFR, led to a net reclassification improvement of 6.87% (P=0.04). Not censoring the patients at the start of dialysis and continuing follow-up even after dialysis, FGF23 levels did not predict the outcome (HR, 1.16 (0.91-1.48)). Complete case analyses yielded similar results. CONCLUSIONS Intact FGF23 levels in predialysis CKD predicted incident cardiovascular events requiring hospitalization before starting dialysis, but did not predict events during the entire follow-up period, including post dialysis initiation.
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Affiliation(s)
- Chikako Nakano
- Department of Geriatric Medicine and Nephrology, Osaka University Graduate School of Medicine, Osaka, Japan
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Duranton F, Cohen G, De Smet R, Rodriguez M, Jankowski J, Vanholder R, Argiles A. Normal and pathologic concentrations of uremic toxins. J Am Soc Nephrol 2012; 23:1258-70. [PMID: 22626821 DOI: 10.1681/asn.2011121175] [Citation(s) in RCA: 690] [Impact Index Per Article: 57.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
An updated review of the existing knowledge regarding uremic toxins facilitates the design of experimental studies. We performed a literature search and found 621 articles about uremic toxicity published after a 2003 review of this topic. Eighty-seven records provided serum or blood measurements of one or more solutes in patients with CKD. These records described 32 previously known uremic toxins and 56 newly reported solutes. The articles most frequently reported concentrations of β2-microglobulin, indoxyl sulfate, homocysteine, uric acid, and parathyroid hormone. We found most solutes (59%) in only one report. Compared with previous results, more recent articles reported higher uremic concentrations of many solutes, including carboxymethyllysine, cystatin C, and parathyroid hormone. However, five solutes had uremic concentrations less than 10% of the originally reported values. Furthermore, the uremic concentrations of four solutes did not exceed their respective normal concentrations, although they had been previously described as uremic retention solutes. In summary, this review extends the classification of uremic retention solutes and their normal and uremic concentrations, and it should aid the design of experiments to study the biologic effects of these solutes in CKD.
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15
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Tanaka H, Komaba H, Koizumi M, Kakuta T, Fukagawa M. Role of uremic toxins and oxidative stress in the development of chronic kidney disease-mineral and bone disorder. J Ren Nutr 2012; 22:98-101. [PMID: 22200424 DOI: 10.1053/j.jrn.2011.10.031] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2011] [Accepted: 10/13/2011] [Indexed: 12/21/2022] Open
Abstract
The kidney plays an important role in the regulation of mineral metabolism. As kidney function declines, there is a progressive deterioration in mineral homeostasis, along with various abnormalities, including bone disease and vascular calcification, which has recently been named as "Chronic Kidney Disease-Mineral and Bone Disorder (CKD-MBD)." Although the precise mechanisms of this systemic disorder remain to be elucidated, accumulating evidence suggest that uremic toxins contribute substantially to the development of CKD-MBD, partly through evoking oxidative stress in the bone and cardiovascular systems. This brief review summarizes recent work on the role of uremic toxins and oxidative stress in the development of CKD-MBD.
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Affiliation(s)
- Hisae Tanaka
- Division of Nephrology, Endocrinology, and Metabolism, Tokai University School of Medicine, Isehara, Kanagawa, Japan
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Mozar A, Louvet L, Godin C, Mentaverri R, Brazier M, Kamel S, Massy ZA. Indoxyl sulphate inhibits osteoclast differentiation and function. Nephrol Dial Transplant 2011; 27:2176-81. [PMID: 22140126 DOI: 10.1093/ndt/gfr647] [Citation(s) in RCA: 65] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
BACKGROUND Patients with chronic kidney disease (CKD) develop various bone abnormalities characterized by impaired bone remodelling. Recent data suggest that accumulation of the uraemic toxin indoxyl sulphate (IS) may be one of the factors involved in bone abnormalities in CKD patients. Indeed, it was recently reported that IS induces skeletal resistance to parathyroid hormone in cultured osteoblastic cells. However, it is not yet known whether IS also affects osteoclast cells. METHODS In the present study, we assessed the direct effect of IS at uraemic concentrations and in the presence (to reach the 3 mM concentration) or absence of added inorganic phosphate (Pi) on osteoclast (OCL) differentiation and bone-resorbing activity in two well-established cellular models of monocyte/macrophage (peripheral blood mononuclear cells and the RAW 264.7 cell line). RESULTS We found that IS inhibits both OCL differentiation and bone-resorbing activity in a dose-dependent manner and that these effects were enhanced in the presence of Pi at 3mM concentration. IS induced a gradual inhibition of JNK, Akt, p38, ERK1/2 phosphorylation and AP-1 DNA-binding activity. The effects of IS on OCL differentiation and AP-1 were prevented by probenecid, a competitive inhibitor of organic anion transporters, suggesting that IS's effects occur subsequently to its intake. CONCLUSION Our findings strongly suggest that IS not only inhibits osteoblast function but also has an inhibitory effect on OCL function and thus could affect bone remodelling in CKD patients.
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Niwa T. Update of uremic toxin research by mass spectrometry. MASS SPECTROMETRY REVIEWS 2011; 30:510-521. [PMID: 21328600 DOI: 10.1002/mas.20323] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/30/2010] [Revised: 09/29/2010] [Accepted: 09/29/2010] [Indexed: 05/30/2023]
Abstract
Mass spectrometry (MS) has been successfully applied for the identification and quantification of uremic toxins and uremia-associated modified proteins. This review focuses on the recent progress in the MS analysis of uremic toxins. Uremic toxins include low-molecular weight solutes, protein-bound low-molecular weight solutes, and middle molecules (peptides and proteins). Based on MS analysis of these uremic toxins, the pathogenesis of the uremic symptoms will be elucidated to prevent and manage the symptoms. Notably, protein-bound uremic toxins such as indoxyl sulfate, p-cresyl sulfate, and 3-carboxy-4-methyl-5-propyl-2-furanpropionic acid have emerged as important targets of therapeutic removal. Hemodialysis even with a high-flux membrane cannot efficiently remove the protein-bound uremic toxins because of their high albumin-binding property. The accumulation of these protein-bound uremic toxins in the blood of dialysis patients might play an important role in the development of uremic complications such as cardiovascular disease. Indoxyl sulfate is the most promising protein-bound uremic toxin as a biomarker of progress in chronic kidney disease. Novel dialysis techniques or membranes should be developed to efficiently remove these protein-bound uremic toxins for the prevention and management of uremic complications.
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Affiliation(s)
- Toshimitsu Niwa
- Department of Advanced Medicine for Uremia, Nagoya University Graduate School of Medicine, 65 Tsurumai-cho, Showa-ku, Nagoya 466-8550, Japan.
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Abstract
Uremic toxins are associated with various disorders in patients with end-stage renal disease and it is difficult to remove some of these toxins by dialysis. Since some uremic toxins are generated by bacterial metabolites in the colon, oral adsorbents that interfere with the absorption of uremic toxins or their precursors are believed to prevent their accumulation in the body. AST-120 adsorbs various uremic retention solutes in the gastrointestinal system and has potential for providing clinical benefit. Sevelamer hydrochloride binds some harmful compounds in addition to phosphate and seems to have pleiotropic effects that include lowering serum LDL cholesterol levels and reduction of inflammation. The effect of sevelamer hydrochloride on indoxyl sulfate and p-cresol has been shown in an in vitro study; however, in vivo studies in mice or humans did not demonstrate this effect on protein-binding uremic toxins. Oral adsorbents are thus one of the important modalities in the treatment of uremic syndrome.
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Affiliation(s)
- Shunsuke Goto
- Division of Nephrology and Kidney Center, Kobe University Graduate School of Medicine, Kobe, Japan.
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Fujii H, Nakai K, Fukagawa M. Role of oxidative stress and indoxyl sulfate in progression of cardiovascular disease in chronic kidney disease. Ther Apher Dial 2011; 15:125-8. [PMID: 21426501 DOI: 10.1111/j.1744-9987.2010.00883.x] [Citation(s) in RCA: 69] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Several abnormalities of the cardiovascular system are observed in most cases of chronic kidney disease (CKD). Mechanisms underlying these abnormalities are complicated, and several factors contribute to their pathogenesis. Of these factors, oxidative stress and uremic toxins are considered to play key roles in the progression of cardiovascular disease (CVD) in CKD. Oxidative stress increases significantly in CKD and accelerates proteinuria and renal dysfunction. In addition, oxidative stress has been reported to induce cardiac hypertrophy and fibrosis. Indoxyl sulfate, a uremic toxin, has recently been suggested to play a crucial role in the development of CVD. Recent in vitro data suggest that indoxyl sulfate increases oxidative stress. Some reports have shown that AST-120, which is an oral charcoal adsorbent, can reduce oxidative stress by lowering serum indoxyl sulfate levels. Recently, we have also demonstrated that indoxyl sulfate is associated with the production of oxidative stress, and that increased oxidative stress is significantly correlated with cardiac hypertrophy and fibrosis. Furthermore, results of our basic and clinical studies suggested that AST-120 can prevent progression of cardiac hypertrophy by reducing oxidative stress in CKD. Thus, one of the main targets of the management of CKD and CVD is the control of oxidative stress and uremic toxins, such as indoxyl sulfate.
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Affiliation(s)
- Hideki Fujii
- Division of Nephrology and Kidney Center, Kobe University Graduate School of Medicine, Kobe, Japan.
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