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Song T, Wang R, Zhou X, Chen W, Chen Y, Liu Z, Men L. Metabolomics and molecular dynamics unveil the therapeutic potential of epalrestat in diabetic nephropathy. Int Immunopharmacol 2024; 140:112812. [PMID: 39094360 DOI: 10.1016/j.intimp.2024.112812] [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: 05/19/2024] [Revised: 07/12/2024] [Accepted: 07/24/2024] [Indexed: 08/04/2024]
Abstract
Diabetic nephropathy (DN) is one of the leading clinical causes of end-stage renal failure. The classical aldose reductase (AR) inhibitor epalrestat shows beneficial effect on renal dysfunction induced by DN, with metabolic profile and molecular mechanisms remains to be investigated further. In the current study, integrated untargeted metabolomics, network pharmacology and molecular dynamics approaches were applied to explore the therapeutic mechanisms of epalrestat against DN. Firstly, untargeted serum and urine metabolomics analysis based on UPLC-Q-TOF-MS was performed, revealed that epalrestat could regulate the metabolic disorders of amino acids metabolism, arachidonic acid metabolism, pyrimidine metabolism and citrate cycle metabolism pathways after DN. Subsequently, metabolomics-based network analysis was carried out to predict potential active targets of epalrestat, mainly involving AGE-RAGE signaling pathway, TNF signaling pathway and HIF-1 signaling pathway. Moreover, a 100 ns molecular dynamics approach was employed to validate the interactions between epalrestat and the core targets, showing that epalrestat could form remarkable tight binding with GLUT1 and NFκB than it with AR. Surface-plasmon resonance assay further verified epalrestat could bind GLUT1 and NFκB proteins specifically. Overall, integrated system network analysis not only demonstrated that epalrestat could attenuate DN induced metabolic disorders and renal injuries, but also revealed that it could interact with multi-targets to play a synergistic regulatory role in the treatment of DN.
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Affiliation(s)
- Tongtong Song
- College of Basic Medical Sciences, Jilin University, Changchun 130021, PR China
| | - Rongjin Wang
- School of Pharmaceutical Sciences, Jilin University, Changchun 130021, PR China
| | - Xiaoyue Zhou
- The First Hospital of Jilin University, Changchun 130052, PR China
| | - Weijia Chen
- College of Chinese Medicinal Materials, Jilin Agricultural University, Changchun 130118, PR China
| | - Ying Chen
- The First Hospital of Jilin University, Changchun 130052, PR China
| | - Zhongying Liu
- School of Pharmaceutical Sciences, Jilin University, Changchun 130021, PR China
| | - Lihui Men
- College of Basic Medical Sciences, Jilin University, Changchun 130021, PR China.
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2
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Jin WY, Guo JX, Tang R, Wang J, Zhao H, Zhang M, Teng LZ, Sansonetti PJ, Gao YZ. In vivo detection of endogenous toxic phenolic compounds of intestine. JOURNAL OF HAZARDOUS MATERIALS 2024; 478:135526. [PMID: 39153300 DOI: 10.1016/j.jhazmat.2024.135526] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/03/2024] [Revised: 07/31/2024] [Accepted: 08/13/2024] [Indexed: 08/19/2024]
Abstract
Phenol and p-cresol are two common toxic small molecules related to various diseases. Existing reports confirmed that high L-tyrosine in the daily diet can increase the concentration of phenolic compounds in blood and urine. L-tyrosine is a common component of protein-rich foods. Some anaerobic bacteria in the gut can convert non-toxic l-tyrosine into these two toxic phenolic compounds, phenol and p-cresol. Existing methods have been constructed for measuring the concentration of phenolic compound in feces. However, there is still a lack of direct visual evidence to measure the phenolic compounds in the intestine. In this study, we aimed to construct a whole-cell biosensor for phenolic compounds detection based on the dmpR, the regulator from the phenol metabolism cluster. The commensal bacterium Citrobacter amalonaticus PS01 was selected and used as the chassis. Compared with the biosensor based on ECN1917, the biosensor PS01[dmpR] could better implant into the mouse gut through gavage and showed a higher sensitive to phenolic compound. And the concentration of phenolic compounds in the intestines could be observed with the help of in vivo imaging system using PS01[dmpR]. This paper demonstrated endogenous phenol synthesis in the gut and the strategy of using commensal bacteria to construct whole-cell biosensors for detecting small molecule compounds in the intestines.
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Affiliation(s)
- Wen-Yu Jin
- Key Laboratory of Molecular Virology and Immunology, Shanghai Institute of Immunity and Infection, Chinese Academy of Sciences, Shanghai 200031, China; The Center for Microbes, Development, and Health, Shanghai Institute of Immunity and Infection, Chinese Academy of Sciences, Shanghai 200031, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Jia-Xin Guo
- Key Laboratory of Molecular Virology and Immunology, Shanghai Institute of Immunity and Infection, Chinese Academy of Sciences, Shanghai 200031, China; The Center for Microbes, Development, and Health, Shanghai Institute of Immunity and Infection, Chinese Academy of Sciences, Shanghai 200031, China
| | - Rongkang Tang
- Key Laboratory of Molecular Virology and Immunology, Shanghai Institute of Immunity and Infection, Chinese Academy of Sciences, Shanghai 200031, China; The Center for Microbes, Development, and Health, Shanghai Institute of Immunity and Infection, Chinese Academy of Sciences, Shanghai 200031, China
| | - Jielin Wang
- Hongqiao International Institute of Medicine, Tongren Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Huan Zhao
- Department of Oncology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, China
| | - Meng Zhang
- Key Laboratory of Molecular Virology and Immunology, Shanghai Institute of Immunity and Infection, Chinese Academy of Sciences, Shanghai 200031, China; The Center for Microbes, Development, and Health, Shanghai Institute of Immunity and Infection, Chinese Academy of Sciences, Shanghai 200031, China; Pasteurian College, Suzhou Medical College, Soochow University, Suzhou, Jiangsu 215123, China
| | - Lin-Zuo Teng
- Key Laboratory of Molecular Virology and Immunology, Shanghai Institute of Immunity and Infection, Chinese Academy of Sciences, Shanghai 200031, China; The Center for Microbes, Development, and Health, Shanghai Institute of Immunity and Infection, Chinese Academy of Sciences, Shanghai 200031, China
| | - Philippe J Sansonetti
- Key Laboratory of Molecular Virology and Immunology, Shanghai Institute of Immunity and Infection, Chinese Academy of Sciences, Shanghai 200031, China; The Center for Microbes, Development, and Health, Shanghai Institute of Immunity and Infection, Chinese Academy of Sciences, Shanghai 200031, China; University of Chinese Academy of Sciences, Beijing 100049, China; Unité de Pathogénie Microbienne Moléculaire, Institut Pasteur, Université de Paris, Paris, France.
| | - Yi-Zhou Gao
- Key Laboratory of Molecular Virology and Immunology, Shanghai Institute of Immunity and Infection, Chinese Academy of Sciences, Shanghai 200031, China; The Center for Microbes, Development, and Health, Shanghai Institute of Immunity and Infection, Chinese Academy of Sciences, Shanghai 200031, China; University of Chinese Academy of Sciences, Beijing 100049, China.
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Al-Dajani AR, Kiang TKL. A high-throughput liquid chromatography-tandem mass spectrometry assay for the simultaneous quantification of p-cresol sulfate, p-cresol glucuronide, indoxyl sulfate, and indoxyl glucuronide in HepaRG culture medium and the demonstration of mefenamic acid as a potent and selective detoxifying agent. Expert Opin Drug Metab Toxicol 2024:1-13. [PMID: 39323391 DOI: 10.1080/17425255.2024.2409257] [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: 06/22/2024] [Accepted: 09/18/2024] [Indexed: 09/27/2024]
Abstract
BACKGROUND p-cresol and indole are uremic compounds which undergo sulfonation to generate the highly toxic p-cresol sulfate (pCS) and indoxyl sulfate (IxS). They are also subjected to glucuronidation to produce the less toxic p-cresol glucuronide (pCG) and indoxyl glucuronide (IG). We developed and validated an assay to quantify these metabolites in HepaRG cells. We also tested the effects of mefenamic acid on their in-situ formations in relation to the development of cellular necrosis. RESEARCH DESIGN AND METHODS HepaRG cells were exposed to p-cresol or indole (0-1 mM) with mefenamic acid (0-3000 nM) for 24 hours to generate uremic metabolites. Cells were also exposed to 0.5 mM p-cresol or indole with/without 30 nM mefenamic acid to characterize lactate dehydrogenase (LDH) release. RESULTS The assay exhibited high sensitivity and wide calibration ranges covering human concentrations. HepaRG cells also generated physiologically-relevant concentrations of each metabolite. Mefenamic acid inhibited pCS formation in a concentration-dependent manner without affecting pCG, IxS, or IG. Mefenamic acid also reduced LDH release from p-cresol (by 50.12±5.86%) or indole (56.26±3.58%). CONCLUSIONS This novel assay is capable of quantifying these metabolites in HepaRG cells. Our novel findings suggest that mefenamic acid can be potentially utilized therapeutically to attenuate pCS-associated toxicities.
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Affiliation(s)
- Ala'a R Al-Dajani
- Faculty of Pharmacy and Pharmaceutical Sciences, University of Alberta, Alberta, Canada
| | - Tony K L Kiang
- Faculty of Pharmacy and Pharmaceutical Sciences, University of Alberta, Alberta, Canada
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Mankhong S, Den-Udom T, Tanawattanasuntorn T, Suriyun T, Muta K, Kitiyakara C, Ketsawatsomkron P. The microbial metabolite p-cresol compromises the vascular barrier and induces endothelial cytotoxicity and inflammation in a 3D human vessel-on-a-chip. Sci Rep 2024; 14:18553. [PMID: 39122790 PMCID: PMC11316076 DOI: 10.1038/s41598-024-69124-w] [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: 03/02/2024] [Accepted: 07/31/2024] [Indexed: 08/12/2024] Open
Abstract
Increased protein-bound uremic toxins (PBUTs) in patients with chronic kidney disease (CKD) are associated with cardiovascular diseases (CVDs); however, whether retention of PBUTs causes CVD remains unclear. Previous studies assessing the impacts of PBUTs on the vasculature have relied on 2D cell cultures lacking in vivo microenvironments. Here, we investigated the impact of various PBUTs (p-cresol (PC), indoxyl sulfate (IS), and p-cresyl sulfate (PCS)) on microvascular function using an organ-on-a-chip (OOC). Human umbilical vein endothelial cells were used to develop 3D vessels. Chronic exposure to PC resulted in significant vascular leakage compared with controls, whereas IS or PCS treatment did not alter the permeability of 3D vessels. Increased permeability induced by PC was correlated with derangement of cell adherens junction complex, vascular endothelial (VE)-cadherin and filamentous (F)-actin. Additionally, PC decreased endothelial viability in a concentration-dependent manner with a lower IC50 in 3D vessels than in 2D cultures. IS slightly decreased cell viability, while PCS did not affect viability. PC induced inflammatory responses by increasing monocyte adhesion to endothelial surfaces of 3D vessels and IL-6 production. In conclusion, this study leveraged an OOC to determine the diverse effects of PBUTs, demonstrating that PC accumulation is detrimental to ECs during kidney insufficiency.
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Affiliation(s)
- Sakulrat Mankhong
- Chakri Naruebodindra Medical Institute, Faculty of Medicine Ramathibodi Hospital, Mahidol University, 111 Moo 14, Bang Pla, Bang Phli, Samut Prakan, 10540, Thailand
| | - Thittaya Den-Udom
- Chakri Naruebodindra Medical Institute, Faculty of Medicine Ramathibodi Hospital, Mahidol University, 111 Moo 14, Bang Pla, Bang Phli, Samut Prakan, 10540, Thailand
- Program in Translational Medicine, Faculty of Medicine Ramathibodi Hospital, Mahidol University, Bangkok, Thailand
| | - Tanotnon Tanawattanasuntorn
- Chakri Naruebodindra Medical Institute, Faculty of Medicine Ramathibodi Hospital, Mahidol University, 111 Moo 14, Bang Pla, Bang Phli, Samut Prakan, 10540, Thailand
| | - Thunwarat Suriyun
- Chakri Naruebodindra Medical Institute, Faculty of Medicine Ramathibodi Hospital, Mahidol University, 111 Moo 14, Bang Pla, Bang Phli, Samut Prakan, 10540, Thailand
| | - Kenjiro Muta
- Chakri Naruebodindra Medical Institute, Faculty of Medicine Ramathibodi Hospital, Mahidol University, 111 Moo 14, Bang Pla, Bang Phli, Samut Prakan, 10540, Thailand
| | - Chagriya Kitiyakara
- Department of Medicine, Faculty of Medicine Ramathibodi Hospital, Mahidol University, Bangkok, Thailand
| | - Pimonrat Ketsawatsomkron
- Chakri Naruebodindra Medical Institute, Faculty of Medicine Ramathibodi Hospital, Mahidol University, 111 Moo 14, Bang Pla, Bang Phli, Samut Prakan, 10540, Thailand.
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Chen SJ, Wu YJ, Chen CC, Wu YW, Liou JM, Wu MS, Kuo CH, Lin CH. Plasma metabolites of aromatic amino acids associate with clinical severity and gut microbiota of Parkinson's disease. NPJ Parkinsons Dis 2023; 9:165. [PMID: 38097625 PMCID: PMC10721883 DOI: 10.1038/s41531-023-00612-y] [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: 07/26/2023] [Accepted: 11/24/2023] [Indexed: 12/17/2023] Open
Abstract
Gut microbial proteolytic metabolism has been reportedly altered in Parkinson's disease (PD). However, the circulating aromatic amino acids (AAA) described in PD are inconsistent. Here we aimed to investigate plasma AAA profiles in a large cohort of PD patients, and examine their correlations with clinical severity and gut microbiota changes. We enrolled 500 participants including 250 PD patients and 250 neurologically normal controls. Plasma metabolites were measured using liquid chromatography mass spectrometry. Faecal samples were newly collected from 154 PD patients for microbiota shotgun metagenomic sequencing combined with data derived from 96 PD patients reported before. Data were collected regarding diet, medications, and motor and non-motor symptoms of PD. Compared to controls, PD patients had higher plasma AAA levels, including phenylacetylglutamine (PAGln), p-cresol sulfate (Pcs), p-cresol glucuronide (Pcg), and indoxyl sulfate (IS). Multivariable linear regression analyses, with adjustment for age, sex, and medications, revealed that the plasma levels of PAGln (coefficient 4.49, 95% CI 0.40-8.58, P = 0.032) and Pcg (coefficient 1.79, 95% CI 0.07-3.52, P = 0.042) positively correlated with motor symptom severity but not cognitive function. After correcting for abovementioned potential confounders, these AAA metabolites were also associated with the occurrence of constipation in PD patients (all P < 0.05). Furthermore, plasma levels of AAA metabolites were correlated with the abundance of specific gut microbiota species, including Bacteroides sp. CF01-10NS, Bacteroides vulgatus, and Clostridium sp. AF50-3. In conclusion, elevated plasma AAA metabolite levels correlated with disease characteristics in PD, suggesting that upregulated proteolytic metabolism may contribute to the pathophysiology of PD.
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Affiliation(s)
- Szu-Ju Chen
- Department of Neurology, National Taiwan University Hospital, College of Medicine, National Taiwan University, Taipei, Taiwan
- Department of Neurology, National Taiwan University Hospital Bei-Hu Branch, Taipei, Taiwan
- Graduate Institute of Clinical Medicine, College of Medicine, National Taiwan University, Taipei, Taiwan
| | - Yu-Jun Wu
- School of Pharmacy, College of Medicine, National Taiwan University, Taipei, Taiwan
| | - Chieh-Chang Chen
- Graduate Institute of Clinical Medicine, College of Medicine, National Taiwan University, Taipei, Taiwan
- Division of Gastroenterology and Hepatology, Department of Internal Medicine, National Taiwan University Hospital, College of Medicine, National Taiwan University, Taipei, Taiwan
| | - Yu-Wei Wu
- Graduate Institute of Biomedical Informatics, College of Medical Science and Technology, Taipei Medical University, Taipei, Taiwan
| | - Jyh-Ming Liou
- Division of Gastroenterology and Hepatology, Department of Internal Medicine, National Taiwan University Hospital, College of Medicine, National Taiwan University, Taipei, Taiwan
| | - Ming-Shiang Wu
- Division of Gastroenterology and Hepatology, Department of Internal Medicine, National Taiwan University Hospital, College of Medicine, National Taiwan University, Taipei, Taiwan
| | - Ching-Hua Kuo
- Graduate Institute of Biomedical Informatics, College of Medical Science and Technology, Taipei Medical University, Taipei, Taiwan.
- The Metabolomics Core Laboratory, NTU Centers of Genomic and Precision Medicine, National Taiwan University, Taipei, Taiwan.
- Department of Pharmacy, National Taiwan University Hospital, Taipei, Taiwan.
| | - Chin-Hsien Lin
- Department of Neurology, National Taiwan University Hospital, College of Medicine, National Taiwan University, Taipei, Taiwan.
- Institute of Molecular Medicine, College of Medicine, National Taiwan University, Taipei, Taiwan.
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6
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Meyer TW, Bargman JM. The Removal of Uremic Solutes by Peritoneal Dialysis. J Am Soc Nephrol 2023; 34:1919-1927. [PMID: 37553867 PMCID: PMC10703087 DOI: 10.1681/asn.0000000000000211] [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: 05/16/2023] [Accepted: 07/24/2023] [Indexed: 08/10/2023] Open
Abstract
ABSTRACT Peritoneal dialysis (PD) is now commonly prescribed to achieve target clearances for urea or creatinine. The International Society for Peritoneal Dialysis has proposed however that such targets should no longer be imposed. The Society's new guidelines suggest rather that the PD prescription should be adjusted to achieve well-being in individual patients. The relaxation of treatment targets could allow increased use of PD. Measurement of solute levels in patients receiving dialysis individualized to relieve uremic symptoms could also help us identify the solutes responsible for those symptoms and then devise new means to limit their accumulation. This possibility has prompted us to review the extent to which different uremic solutes are removed by PD.
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Affiliation(s)
- Timothy W. Meyer
- Departments of Medicine, Stanford University and VA Palo Alto HCS, Palo Alto, California
| | - Joanne M. Bargman
- Division of Nephrology and Department of Medicine, University Health Network and the University of Toronto, Canada
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Vallianou NG, Kounatidis D, Panagopoulos F, Evangelopoulos A, Stamatopoulos V, Papagiorgos A, Geladari E, Dalamaga M. Gut Microbiota and Its Role in the Brain-Gut-Kidney Axis in Hypertension. Curr Hypertens Rep 2023; 25:367-376. [PMID: 37632662 DOI: 10.1007/s11906-023-01263-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/08/2023] [Indexed: 08/28/2023]
Abstract
PURPOSE OF REVIEW The role of the gut microbiota in modulating blood pressure is increasingly being recognized, currently. The purpose of this review is to summarize recent findings about the mechanisms involved in hypertension with regard to the phenomenon of "gut dysbiosis." RECENT FINDINGS Gut dysbiosis, i.e., the imbalance between the gut microbiota and the host, is characterized by a disruption of the tight junction proteins, such as occludins, claudins, and JAMs (junctional adhesion molecules), resulting in increased gut permeability or the so called "leaky gut." Due to the influence of genetic as well as environmental factors, various metabolites produced by the gut microbiota, such as indole and p-cresol, are increased. Thereby, uremic toxins, such as indoxyl sulfates and p-cresol sulfates, accumulate in the blood and the urine, causing damage in the podocytes and the tubular cells. In addition, immunological mechanisms are implicated as well. In particular, a switch from M2 macrophages to M1 macrophages, which produce pro-inflammatory cytokines, occurs. Moreover, a higher level of Th17 cells, releasing large amounts of interleukin-17 (IL-17), has been reported, when a diet rich in salt is consumed. Therefore, apart from the aggravation of uremic toxins, which may account for direct harmful effects on the kidney, there is inflammation not only in the gut, but in the kidneys as well. This crosstalk between the gut and the kidney is suggested to play a crucial role in hypertension. Notably, the brain is also implicated, with an increasing sympathetic output. The brain-gut-kidney axis seems to be deeply involved in the development of hypertension and chronic kidney disease (CKD). The notion that, by modulating the gut microbiota, we could regulate blood pressure is strongly supported by the current evidence. A healthy diet, low in animal protein and fat, and low in salt, together with the utilization of probiotics, prebiotics, synbiotics, or postbiotics, may contribute to our fight against hypertension.
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Affiliation(s)
| | | | - Fotis Panagopoulos
- Evangelismos General Hospital, 45-47 Ipsilantou str, 10676, Athens, Greece
| | | | | | | | - Eleni Geladari
- Evangelismos General Hospital, 45-47 Ipsilantou str, 10676, Athens, Greece
| | - Maria Dalamaga
- Department of Biological Chemistry, Medical School, National and Kapodistrian University of Athens, 75 Mikras Asias str, Athens, Greece
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Day F, O’Sullivan J, Pook C. 4-Ethylphenol-fluxes, metabolism and excretion of a gut microbiome derived neuromodulator implicated in autism. Front Mol Biosci 2023; 10:1267754. [PMID: 37900921 PMCID: PMC10602680 DOI: 10.3389/fmolb.2023.1267754] [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: 07/28/2023] [Accepted: 09/26/2023] [Indexed: 10/31/2023] Open
Abstract
Gut-microbiome-derived metabolites, such as 4-Ethylphenol [4EP], have been shown to modulate neurological health and function. Although the source of such metabolites is becoming better understood, knowledge gaps remain as to the mechanisms by which they enter host circulation, how they are transported in the body, how they are metabolised and excreted, and the way they exert their effects. High blood concentrations of host-modified 4EP, 4-ethylphenol sulfate [4EPS], are associated with an anxiety phenotype in autistic individuals. We have reviewed the existing literature and discuss mechanisms that are proposed to contribute influx from the gut microbiome, metabolism, and excretion of 4EP. We note that increased intestinal permeability is common in autistic individuals, potentially explaining increased flux of 4EP and/or 4EPS across the gut epithelium and the Blood Brain Barrier [BBB]. Similarly, kidney dysfunction, another complication observed in autistic individuals, impacts clearance of 4EP and its derivatives from circulation. Evidence indicates that accumulation of 4EPS in the brain of mice affects connectivity between subregions, particularly those linked to anxiety. However, we found no data on the presence or quantity of 4EP and/or 4EPS in human brains, irrespective of neurological status, likely due to challenges sampling this organ. We argue that the penetrative ability of 4EP is dependent on its form at the BBB and its physicochemical similarity to endogenous metabolites with dedicated active transport mechanisms across the BBB. We conclude that future research should focus on physical (e.g., ingestion of sorbents) or metabolic mechanisms (e.g., conversion to 4EP-glucuronide) that are capable of being used as interventions to reduce the flux of 4EP from the gut into the body, increase the efflux of 4EP and/or 4EPS from the brain, or increase excretion from the kidneys as a means of addressing the neurological impacts of 4EP.
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Affiliation(s)
- Francesca Day
- Liggins Institute, Waipapa Taumata Rau—The University of Auckland, Auckland, New Zealand
| | - Justin O’Sullivan
- Liggins Institute, Waipapa Taumata Rau—The University of Auckland, Auckland, New Zealand
- The Maurice Wilkins Centre, The University of Auckland, Auckland, New Zealand
- MRC Lifecourse Epidemiology Unit, University of Southampton, Southampton, United Kingdom
- Australian Parkinson’s Mission, Garvan Institute of Medical Research, Sydney, NSW, Australia
- A*STAR Singapore Institute for Clinical Sciences, Singapore, Singapore
| | - Chris Pook
- Liggins Institute, Waipapa Taumata Rau—The University of Auckland, Auckland, New Zealand
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Cerebrovascular Disease, Cardiovascular Disease, and Chronic Kidney Disease: Interplays and Influences. Curr Neurol Neurosci Rep 2022; 22:757-766. [PMID: 36181576 DOI: 10.1007/s11910-022-01230-6] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/26/2022] [Indexed: 01/27/2023]
Abstract
PURPOSE OF REVIEW We reviewed reasons for the high cardiovascular risk (CVD) of patients with chronic kidney disease (CKD), and explored alternatives to treatment of traditional risk factors to reduce CVD in CKD. RECENT FINDINGS Besides traditional risk factors, patients with CKD are exposed to uremic toxins of two kinds: systemically derived toxins include asymmetric dimethylarginine (ADMA), total homocysteine (tHcy), thiocyanate, tumor necrosis factor alpha, and interleukin 6. Gut-derived uremic toxins (GDUT), products of the intestinal microbiome, include hippuric acid, indoxyl sulfate, p-cresyl sulfate, p-cresyl glucuronide, phenylacetylglutamine, and trimethylamine N-oxide (TMAO). Cyanocobalamin is toxic in patients with CKD. Approaches to reducing plasma levels of these uremic toxins would include diet to reduce GDUT, kidney transplantation, more intensive dialysis, and vitamin therapy to lower tHcy with methylcobalamin rather than cyanocobalamin. The high CVD risk in CKD requires consideration of therapies beyond treatment of traditional risk factors.
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10
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Lipid Profile Is Negatively Associated with Uremic Toxins in Patients with Kidney Failure-A Tri-National Cohort. Toxins (Basel) 2022; 14:toxins14060412. [PMID: 35737073 PMCID: PMC9231137 DOI: 10.3390/toxins14060412] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2022] [Revised: 06/05/2022] [Accepted: 06/10/2022] [Indexed: 02/04/2023] Open
Abstract
Patients with kidney failure (KF) have a high incidence of cardiovascular (CV) disease, partly driven by insufficient clearance of uremic toxins. Recent investigations have questioned the accepted effects of adverse lipid profile and CV risk in uremic patients. Therefore, we related a panel of uremic toxins previously associated with CV morbidity/mortality to a full lipid profile in a large, tri-national, cross-sectional cohort. Total, high-density lipoprotein (HDL), non-HDL, low-density lipoprotein (LDL), and remnant cholesterol, as well as triglyceride, levels were associated with five uremic toxins in a cohort of 611 adult KF patients with adjustment for clinically relevant covariates and other patient-level variables. Univariate analyses revealed negative correlations of total, non-HDL, and LDL cholesterol with all investigated uremic toxins. Multivariate linear regression analyses confirmed independent, negative associations of phenylacetylglutamine with total, non-HDL, and LDL cholesterol, while indole-3 acetic acid associated with non-HDL and LDL cholesterol. Furthermore, trimethylamine-N-Oxide was independently and negatively associated with non-HDL cholesterol. Sensitivity analyses largely confirmed findings in the entire cohort. In conclusion, significant inverse associations between lipid profile and distinct uremic toxins in KF highlight the complexity of the uremic milieu, suggesting that not all uremic toxin interactions with conventional CV risk markers may be pathogenic.
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Hou K, Wu ZX, Chen XY, Wang JQ, Zhang D, Xiao C, Zhu D, Koya JB, Wei L, Li J, Chen ZS. Microbiota in health and diseases. Signal Transduct Target Ther 2022; 7:135. [PMID: 35461318 PMCID: PMC9034083 DOI: 10.1038/s41392-022-00974-4] [Citation(s) in RCA: 673] [Impact Index Per Article: 336.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2021] [Revised: 03/11/2022] [Accepted: 03/15/2022] [Indexed: 02/07/2023] Open
Abstract
The role of microbiota in health and diseases is being highlighted by numerous studies since its discovery. Depending on the localized regions, microbiota can be classified into gut, oral, respiratory, and skin microbiota. The microbial communities are in symbiosis with the host, contributing to homeostasis and regulating immune function. However, microbiota dysbiosis can lead to dysregulation of bodily functions and diseases including cardiovascular diseases (CVDs), cancers, respiratory diseases, etc. In this review, we discuss the current knowledge of how microbiota links to host health or pathogenesis. We first summarize the research of microbiota in healthy conditions, including the gut-brain axis, colonization resistance and immune modulation. Then, we highlight the pathogenesis of microbiota dysbiosis in disease development and progression, primarily associated with dysregulation of community composition, modulation of host immune response, and induction of chronic inflammation. Finally, we introduce the clinical approaches that utilize microbiota for disease treatment, such as microbiota modulation and fecal microbial transplantation.
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Affiliation(s)
- Kaijian Hou
- Department of Endocrine and Metabolic Diseases, Longhu Hospital, The First Affiliated Hospital of Medical College of Shantou University, Shantou, Guangdong, 515000, China
| | - Zhuo-Xun Wu
- Department of Pharmaceutical Sciences, Institute for Biotechnology, College of Pharmacy and Health Sciences, St. John's University, Queens, NY, 11439, USA
| | - Xuan-Yu Chen
- Department of Pharmaceutical Sciences, Institute for Biotechnology, College of Pharmacy and Health Sciences, St. John's University, Queens, NY, 11439, USA
| | - Jing-Quan Wang
- Department of Pharmaceutical Sciences, Institute for Biotechnology, College of Pharmacy and Health Sciences, St. John's University, Queens, NY, 11439, USA
| | - Dongya Zhang
- Microbiome Research Center, Moon (Guangzhou) Biotech Ltd, Guangzhou, 510535, China
| | - Chuanxing Xiao
- Department of Endocrine and Metabolic Diseases, Longhu Hospital, The First Affiliated Hospital of Medical College of Shantou University, Shantou, Guangdong, 515000, China
| | - Dan Zhu
- Department of Endocrine and Metabolic Diseases, Longhu Hospital, The First Affiliated Hospital of Medical College of Shantou University, Shantou, Guangdong, 515000, China
| | - Jagadish B Koya
- Department of Pharmaceutical Sciences, Institute for Biotechnology, College of Pharmacy and Health Sciences, St. John's University, Queens, NY, 11439, USA
| | - Liuya Wei
- School of Pharmacy, Weifang Medical University, Weifang, Shandong, 261053, China
| | - Jilin Li
- Department of Cardiovascular, The Second Affiliated Hospital of Medical College of Shantou University, Shantou, Guangdong, 515000, China
| | - Zhe-Sheng Chen
- Department of Pharmaceutical Sciences, Institute for Biotechnology, College of Pharmacy and Health Sciences, St. John's University, Queens, NY, 11439, USA
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El Chamieh C, Liabeuf S, Massy Z. Uremic Toxins and Cardiovascular Risk in Chronic Kidney Disease: What Have We Learned Recently beyond the Past Findings? Toxins (Basel) 2022; 14:280. [PMID: 35448889 PMCID: PMC9028122 DOI: 10.3390/toxins14040280] [Citation(s) in RCA: 20] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2022] [Revised: 04/10/2022] [Accepted: 04/11/2022] [Indexed: 12/13/2022] Open
Abstract
Patients with chronic kidney disease (CKD) have an elevated prevalence of atheromatous (ATH) and/or non-atheromatous (non-ATH) cardiovascular disease (CVD) due to an array of CKD-related risk factors, such as uremic toxins (UTs). Indeed, UTs have a major role in the emergence of a spectrum of CVDs, which constitute the leading cause of death in patients with end-stage renal disease. The European Uremic Toxin Work Group has identified over 100 UTs, more than 25 of which are dietary or gut-derived. Even though relationships between UTs and CVDs have been described in the literature, there are few reviews on the involvement of the most toxic compounds and the corresponding physiopathologic mechanisms. Here, we review the scientific literature on the dietary and gut-derived UTs with the greatest toxicity in vitro and in vivo. A better understanding of these toxins' roles in the elevated prevalence of CVDs among CKD patients might facilitate the development of targeted treatments. Hence, we review (i) ATH and non-ATH CVDs and the respective levels of risk in patients with CKD and (ii) the mechanisms that underlie the influence of dietary and gut-derived UTs on CVDs.
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Affiliation(s)
- Carolla El Chamieh
- Center for Research in Epidemiology and Population Health (CESP), Paris-Saclay University, Versailles-Saint-Quentin-en-Yvelines University (UVSQ), INSERM UMRS 1018, F-94807 Villejuif, France;
| | - Sophie Liabeuf
- Pharmacology Department, Amiens University Hospital, F-80000 Amiens, France
- MP3CV Laboratory, EA7517, Jules Verne University of Picardie, F-80000 Amiens, France
| | - Ziad Massy
- Nephrology Department, Ambroise Paré University Hospital, APHP, F-92100 Paris, France
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Significant Correlations between p-Cresol Sulfate and Mycophenolic Acid Plasma Concentrations in Adult Kidney Transplant Recipients. Clin Drug Investig 2022; 42:207-219. [PMID: 35182318 DOI: 10.1007/s40261-022-01121-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/23/2022] [Indexed: 11/03/2022]
Abstract
BACKGROUND AND OBJECTIVES Mycophenolic acid (MPA) is a commonly prescribed life-long immunosuppressant for kidney transplant recipients. The frequently observed large variations in MPA plasma exposure may lead to severe adverse outcomes; therefore, characterizations of contributing factors can potentially improve the precision dosing of MPA. Our group recently reported the potent inhibitory effects of p-cresol (a protein-bound uremic toxin that can be accumulated in kidney transplant patients) on the hepatic metabolism of MPA in human in vitro models. Based on these data, the hypothesis for this clinical investigation was that a direct correlation between p-cresol and MPA plasma exposure should be evident in adult kidney transplant recipients. METHODS Using a prospective and observational approach, adult kidney transplant recipients within the first year after transplant on oral mycophenolate mofetil (with tacrolimus ± prednisone) were screened for recruitment. The exclusion criteria were cold ischemia time > 30 h, malignancy, pregnancy, severe renal dysfunction (i.e., estimated glomerular filtration rate, eGFR, < 10 mL/min/1.73 m2), active graft rejection, or MPA intolerance. Patients' demographic and biochemistry data were collected. Total and free plasma concentrations of MPA, MPA glucuronide (MPAG), and total p-cresol sulfate (the predominant, quantifiable form of p-cresol in the plasma) were quantified using validated assays. Correlational and categorical analyses were performed using GraphPad Prism. RESULTS Forty patients (11 females) were included: donor type (living/deceased: 20/20), induction regimen (basiliximab/thymoglobulin/basiliximab followed by thymoglobulin: 35/3/2), post-transplant time (74 ± 60 days, mean ± standard deviation), age (53.7 ± 12.4 years), bodyweight (79.8 ± 18.5 kg), eGFR (51.9 ± 18.0 mL/min/1.73 m2), serum albumin (3.6 ± 0.5 g/dL), prednisone dose (18.5 ± 13.2 mg, n = 33), and tacrolimus trough concentration (9.4 ± 2.4 µg/L). Based on Spearman analysis, significant control correlations supporting the validity of our dataset were observed between total MPA trough concentration (C0) and total MPAG C0 (correlation coefficient [R] = 0.39), ratio of total MPAG C0-to-total MPA C0 and post-transplant time (R = - 0.56), total MPAG C0 and eGFR (R = - 0.35), and p-cresol sulfate concentration and eGFR (R = - 0.70). Our primary analysis indicated the novel observation that total MPA C0 (R = 0.39), daily dose-normalized total MPA C0 (R = 0.32), and bodyweight-normalized total MPA C0 (R = 0.32) were significantly correlated with plasma p-cresol sulfate concentrations. Consistently, patients categorized with elevated p-cresol sulfate concentrations (i.e., ≥ median of 3.2 µg/mL) also exhibited increased total MPA C0 (by 57 % vs those below median), daily dose-normalized total MPA C0 (by 89 %), and bodyweight-normalized total MPA C0 (by 62 %). Our secondary analyses with MPA metabolites, unbound concentrations, free fractions, and MPA metabolite ratios supported additional potential interacting mechanisms. CONCLUSION We have identified a novel, positive association between p-cresol sulfate exposure and total MPA C0 in adult kidney transplant recipients, which is supported by published mechanistic in vitro data. Our findings confirm a potential role of p-cresol as a significant clinical variable affecting the pharmacokinetics of MPA. These data also provide the justifications for conducting subsequent full-scale pharmacokinetic-pharmacodynamic studies to further characterize the cause-effect relationships of this interaction, which could also rule out potential confounding variables not adequately controlled in this correlational study.
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Ebrahim Z, Proost S, Tito RY, Raes J, Glorieux G, Moosa MR, Blaauw R. The Effect of ß-Glucan Prebiotic on Kidney Function, Uremic Toxins and Gut Microbiome in Stage 3 to 5 Chronic Kidney Disease (CKD) Predialysis Participants: A Randomized Controlled Trial. Nutrients 2022; 14:nu14040805. [PMID: 35215453 PMCID: PMC8880761 DOI: 10.3390/nu14040805] [Citation(s) in RCA: 19] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2021] [Revised: 12/16/2021] [Accepted: 02/08/2022] [Indexed: 12/21/2022] Open
Abstract
There is growing evidence that gut dysbiosis contributes to the progression of chronic kidney disease (CKD) owing to several mechanisms, including microbiota-derived uremic toxins, diet and immune-mediated factors. The aim of this study was to investigate the effect of a ß-glucan prebiotic on kidney function, uremic toxins and the gut microbiome in stage 3 to 5 CKD participants. Fifty-nine participants were randomized to either the ß-glucan prebiotic intervention group (n = 30) or the control group (n = 29). The primary outcomes were to assess kidney function (urea, creatinine and glomerular filtration rate), plasma levels of total and free levels of uremic toxins (p-cresyl sulfate (pCS), indoxyl-sulfate (IxS), p-cresyl glucuronide (pCG) and indoxyl 3-acetic acid (IAA) and gut microbiota using 16S rRNA sequencing at baseline, week 8 and week 14. The intervention group (age 40.6 ± 11.4 y) and the control group (age 41.3 ± 12.0 y) did not differ in age or any other socio-demographic variables at baseline. There were no significant changes in kidney function over 14 weeks. There was a significant reduction in uremic toxin levels at different time points, in free IxS at 8 weeks (p = 0.003) and 14 weeks (p < 0.001), free pCS (p = 0.006) at 14 weeks and total and free pCG (p < 0.001, p < 0.001, respectively) and at 14 weeks. There were no differences in relative abundances of genera between groups. Enterotyping revealed that the population consisted of only two of the four enterotypes: Bacteroides 2 and Prevotella. The redundancy analysis showed a few factors significantly affected the gut microbiome: these included triglyceride levels (p < 0.001), body mass index (p = 0.002), high- density lipoprotein (p < 0.001) and the prebiotic intervention (p = 0.002). The ß-glucan prebiotic significantly altered uremic toxin levels of intestinal origin and favorably affected the gut microbiome.
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Affiliation(s)
- Zarina Ebrahim
- Division of Human Nutrition, Department of Global Health, Stellenbosch University, Cape Town 8000, South Africa;
- Correspondence: (Z.E.); (S.P.)
| | - Sebastian Proost
- Laboratory of Molecular Bacteriology, Department of Microbiology and Immunology, Rega Institute, KU Leuven, 3000 Leuven, Belgium; (R.Y.T.); (J.R.)
- Center for Microbiology, VIB, 3000 Leuven, Belgium
- Correspondence: (Z.E.); (S.P.)
| | - Raul Yhossef Tito
- Laboratory of Molecular Bacteriology, Department of Microbiology and Immunology, Rega Institute, KU Leuven, 3000 Leuven, Belgium; (R.Y.T.); (J.R.)
- Center for Microbiology, VIB, 3000 Leuven, Belgium
| | - Jeroen Raes
- Laboratory of Molecular Bacteriology, Department of Microbiology and Immunology, Rega Institute, KU Leuven, 3000 Leuven, Belgium; (R.Y.T.); (J.R.)
- Center for Microbiology, VIB, 3000 Leuven, Belgium
| | - Griet Glorieux
- Department of Internal Medicine and Pediatrics, Nephrology Section, Ghent University Hospital, 9000 Ghent, Belgium;
| | | | - Renée Blaauw
- Division of Human Nutrition, Department of Global Health, Stellenbosch University, Cape Town 8000, South Africa;
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Bai X, Liu G, Yang J, Zhu J, Li X. Gut Microbiota as the Potential Mechanism to Mediate Drug Metabolism Under High-Altitude Hypoxia. Curr Drug Metab 2022; 23:8-20. [PMID: 35088664 DOI: 10.2174/1389200223666220128141038] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2021] [Revised: 11/25/2021] [Accepted: 12/30/2021] [Indexed: 11/22/2022]
Abstract
BACKGROUND The characteristics of pharmacokinetics and the activity and expression of drug-metabolizing enzymes and transporters significantly change under a high-altitude hypoxic environment. Gut microbiota is an important factor affecting the metabolism of drugs through direct or indirect effects, changing the bioavailability, biological activity, or toxicity of drugs and further affecting the efficacy and safety of drugs in vivo. A high-altitude hypoxic environment significantly changes the structure and diversity of gut microbiota, which may play a key role in drug metabolism under a high-altitude hypoxic environment. METHODS An investigation was carried out by reviewing published studies to determine the role of gut microbiota in the regulation of drug-metabolizing enzymes and transporters. Data and information on expression change in gut microbiota, drug-metabolizing enzymes and transporters under a high-altitude hypoxic environment were explored and proposed. RESULTS High-altitude hypoxia is an important environmental factor that can adjust the structure of the gut microbiota and change the diversity of intestinal microbes. It was speculated that the gut microbiota could regulate drug-metabolizing enzymes through two potential mechanisms, the first being through direct regulation of the metabolism of drugs in vivo and the second being indirect, i.e., through the regulation of drug-metabolizing enzymes and transporters, thereby affecting the activity of drugs. CONCLUSION This article reviews the effects of high-altitude hypoxia on the gut microbiota and the effects of these changes on drug metabolism.
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Affiliation(s)
- Xue Bai
- Research Center for High Altitude Medicine, Qinghai University Medical College, Xining, China
- State Key Laboratory of Plateau Ecology and Agriculture, Qinghai University, Xining, China
| | - Guiqin Liu
- Research Center for High Altitude Medicine, Qinghai University Medical College, Xining, China
- State Key Laboratory of Plateau Ecology and Agriculture, Qinghai University, Xining, China
| | - Jianxin Yang
- Research Center for High Altitude Medicine, Qinghai University Medical College, Xining, China
| | - Junbo Zhu
- Research Center for High Altitude Medicine, Qinghai University Medical College, Xining, China
| | - Xiangyang Li
- State Key Laboratory of Plateau Ecology and Agriculture, Qinghai University, Xining, China
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16
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Determinants of Hemodialysis Performance: Modeling Fluid and Solute Transport in Hollow-Fiber Dialyzers. REGENERATIVE ENGINEERING AND TRANSLATIONAL MEDICINE 2021; 7:291-300. [PMID: 34926787 DOI: 10.1007/s40883-019-00135-0] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
Hemodialysis constitutes the lifeline of patients with end stage renal disease, yet the parameters that affect hemodialyzer performance remain incompletely understood. We developed a computational model of mass transfer and solute transport in a hollow-fiber dialyzer to gain greater insight into the determinant factors. The model predicts fluid velocity, pressure, and solute concentration profiles for given geometric characteristics, membrane transport properties, and inlet conditions. We examined the impact of transport and structural parameters on uremic solute clearance by varying parameter values within the constraints of standard clinical practice. The model was validated by comparison with published experimental data. Our results suggest solute clearance can be significantly altered by changes in blood and dialysate flow rates, fiber radius and length, and net ultrafiltration rate. Our model further suggests that the main determinant of the clearance of unreactive solutes is their diffusive permeability. The clearance of protein-bound toxins is also strongly determined by blood hematocrit and plasma protein concentrations. Results from this model may serve to optimize hemodialyzer operating conditions in clinical practice to achieve better clearance of pathogenic uremic solutes.
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17
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Mair RD, Lee S, Plummer NS, Sirich TL, Meyer TW. Impaired Tubular Secretion of Organic Solutes in Advanced Chronic Kidney Disease. J Am Soc Nephrol 2021; 32:2877-2884. [PMID: 34408065 PMCID: PMC8806100 DOI: 10.1681/asn.2021030336] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2021] [Accepted: 06/29/2021] [Indexed: 02/04/2023] Open
Abstract
BACKGROUND The clearance of solutes removed by tubular secretion may be altered out of proportion to the GFR in CKD. Recent studies have described considerable variability in the secretory clearance of waste solutes relative to the GFR in patients with CKD. METHODS To test the hypothesis that secretory clearance relative to GFR is reduced in patients approaching dialysis, we used metabolomic analysis to identify solutes in simultaneous urine and plasma samples from 16 patients with CKD and an eGFR of 7±2 ml/min per 1.73 m2 and 16 control participants. Fractional clearances were calculated as the ratios of urine to plasma levels of each solute relative to those of creatinine and urea in patients with CKD and to those of creatinine in controls. RESULTS Metabolomic analysis identified 39 secreted solutes with fractional clearance >3.0 in control participants. Fractional clearance values in patients with CKD were reduced on average to 65%±27% of those in controls. These values were significantly lower for 18 of 39 individual solutes and significantly higher for only one. Assays of the secreted anions phenylacetyl glutamine, p-cresol sulfate, indoxyl sulfate, and hippurate confirmed variable impairment of secretory clearances in advanced CKD. Fractional clearances were markedly reduced for phenylacetylglutamine (4.2±0.6 for controls versus 2.3±0.6 for patients with CKD; P<0.001), p-cresol sulfate (8.6±2.6 for controls versus 4.1±1.5 for patients with CKD; P<0.001), and indoxyl sulfate (23.0±7.3 versus 7.5±2.8; P<0.001) but not for hippurate (10.2±3.8 versus 8.4±2.6; P=0.13). CONCLUSIONS Secretory clearances for many solutes are reduced more than the GFR in advanced CKD. Impaired secretion of these solutes might contribute to uremic symptoms as patients approach dialysis.
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Affiliation(s)
- Robert D. Mair
- Department of Medicine, Stanford University, Palo Alto, California
- Department of Medicine, Veterans Affairs Palo Alto Healthcare System, Palo Alto, California
| | - Seolhyun Lee
- Department of Medicine, Stanford University, Palo Alto, California
- Department of Medicine, Veterans Affairs Palo Alto Healthcare System, Palo Alto, California
| | - Natalie S. Plummer
- Department of Medicine, Stanford University, Palo Alto, California
- Department of Medicine, Veterans Affairs Palo Alto Healthcare System, Palo Alto, California
| | - Tammy L. Sirich
- Department of Medicine, Stanford University, Palo Alto, California
- Department of Medicine, Veterans Affairs Palo Alto Healthcare System, Palo Alto, California
| | - Timothy W. Meyer
- Department of Medicine, Stanford University, Palo Alto, California
- Department of Medicine, Veterans Affairs Palo Alto Healthcare System, Palo Alto, California
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18
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Melekoglu E, Samur FG. Dietary strategies for gut-derived protein-bound uremic toxins and cardio-metabolic risk factors in chronic kidney disease: A focus on dietary fibers. Crit Rev Food Sci Nutr 2021:1-15. [PMID: 34704501 DOI: 10.1080/10408398.2021.1996331] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Abstract
Chronic kidney disease (CKD) is associated with altered composition and function of gut microbiota. The cause of gut dysbiosis in CKD is multifactorial and encompasses the following: uremic state, metabolic acidosis, slow colonic transit, dietary restrictions of plant-based fiber-rich foods, and pharmacological therapies. Dietary restriction of potassium-rich fruits and vegetables, which are common sources of fermentable dietary fibers, inhibits the conversion of dietary fibers to short-chain fatty acids (SCFA), which are the primary nutrient source for the symbiotic gut microbiota. Reduced consumption of fermentable dietary fibers limits the population of SCFA-forming bacteria and causes dysbiosis of gut microbiota. Gut dysbiosis induces colonic fermentation of protein and formation of gut-derived uremic toxins. In this review, we discuss the roles and benefits of dietary fiber on gut-derived protein-bound uremic toxins and plant-based dietary patterns that could be recommended to decrease uremic toxin formation in CKD patients. Recent studies have indicated that dietary fiber supplementation may be useful to decrease gut-derived uremic toxin formation and slow CKD progression. However, research on associations between adherence of healthy dietary patterns and gut-derived uremic toxins formation in patients with CKD is lacking.
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Affiliation(s)
- Ebru Melekoglu
- Faculty of Health Sciences, Nutrition and Dietetics Department, Hacettepe University, Ankara, Turkey.,Faculty of Health Sciences, Nutrition and Dietetics Department, Cukurova University, Adana, Turkey
| | - F Gulhan Samur
- Faculty of Health Sciences, Nutrition and Dietetics Department, Hacettepe University, Ankara, Turkey
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19
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Biruete A, Cross TWL, Allen JM, Kistler BM, de Loor H, Evenepoel P, Fahey GC, Bauer L, Swanson KS, Wilund KR. Effect of Dietary Inulin Supplementation on the Gut Microbiota Composition and Derived Metabolites of Individuals Undergoing Hemodialysis: A Pilot Study. J Ren Nutr 2021; 31:512-522. [PMID: 34120835 PMCID: PMC8403151 DOI: 10.1053/j.jrn.2020.10.003] [Citation(s) in RCA: 30] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2020] [Revised: 10/08/2020] [Accepted: 10/20/2020] [Indexed: 12/19/2022] Open
Abstract
OBJECTIVE The prebiotic fiber inulin has been studied in individuals undergoing hemodialysis (HD) due to its ability to reduce gut microbiota-derived uremic toxins. However, studies examining the effects of inulin on the gut microbiota and derived metabolites are limited in these patients. We aimed to assess the impact of a 4-week supplementation of inulin on the gut microbiota composition and microbial metabolites of patients on HD. DESIGN AND METHODS In a randomized, double-blind, placebo-controlled, crossover study, twelve HD patients (55 ± 10 y, 50% male, 58% Black American, BMI 31.6 ± 8.9 kg/m2, 33% diabetes mellitus) were randomized to consume inulin [10 g/d for females; 15 g/d for males] or maltodextrin [6 g/d for females; 9 g/d for males] for 4 weeks, with a 4-week washout period. We assessed the fecal microbiota composition, fecal metabolites (short-chain fatty acids (SCFA), phenols, and indoles), and plasma indoxyl sulfate and p-cresyl sulfate. RESULTS At baseline, factors that explained the gut microbiota variability included BMI category and type of phosphate binder prescribed. Inulin increased the relative abundance of the phylum Verrucomicrobia and its genus Akkermansia (P interaction = 0.045). Inulin and maltodextrin resulted in an increased relative abundance of the phylum Bacteroidetes and its genus Bacteroides (P time = 0.04 and 0.03, respectively). Both treatments increased the fecal acetate and propionate (P time = 0.032 and 0.027, respectively), and there was a trend toward increased fecal butyrate (P time = 0.06). Inulin did not reduce fecal p-cresol or indoles, or plasma concentrations of p-cresyl sulfate or indoxyl sulfate. CONCLUSIONS A 4-week supplementation of inulin did not lead to major shifts in the fecal microbiota and gut microbiota-derived metabolites. This may be due to high variability among participants and an unexpected increase in fecal excretion of SCFA with maltodextrin. Larger studies are needed to determine the effects of prebiotic fibers on the gut microbiota and clinical outcomes to justify their use in patients on HD.
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Affiliation(s)
- Annabel Biruete
- Division of Nutritional Sciences, University of Illinois, Urbana, Illinois; Division of Nephrology, Department of Medicine, Indiana University School of Medicine, Indianapolis, Indiana
| | - Tzu-Wen L Cross
- Division of Nutritional Sciences, University of Illinois, Urbana, Illinois; Department of Nutrition Science, Purdue University, West Lafayette, Indiana
| | - Jacob M Allen
- Department of Kinesiology and Community Health, University of Illinois, Urbana, Illinois
| | - Brandon M Kistler
- Department of Nutrition and Health Science, Ball State University, Muncie, Indiana
| | - Henriette de Loor
- KU Leuven Department of Microbiology and Immunology, Laboratory of Nephrology, Leuven, Belgium
| | - Pieter Evenepoel
- KU Leuven Department of Microbiology and Immunology, Laboratory of Nephrology, Leuven, Belgium; Department of Nephrology and Renal Transplantation, University Hospitals Leuven, Leuven, Belgium
| | - George C Fahey
- Department of Animal Sciences, University of Illinois, Urbana, Illinois
| | - Laura Bauer
- Department of Animal Sciences, University of Illinois, Urbana, Illinois
| | - Kelly S Swanson
- Division of Nutritional Sciences, University of Illinois, Urbana, Illinois; Department of Animal Sciences, University of Illinois, Urbana, Illinois
| | - Kenneth R Wilund
- Division of Nutritional Sciences, University of Illinois, Urbana, Illinois; Department of Kinesiology and Community Health, University of Illinois, Urbana, Illinois.
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20
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Blachier F, Andriamihaja M. Effects of the L-tyrosine-derived bacterial metabolite p-cresol on colonic and peripheral cells. Amino Acids 2021; 54:325-338. [PMID: 34468872 DOI: 10.1007/s00726-021-03064-x] [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: 05/28/2021] [Accepted: 08/06/2021] [Indexed: 11/28/2022]
Abstract
Specific families of bacteria present within the intestinal luminal content produce p-cresol from L-tyrosine. Although the hosts do not synthesize p-cresol, they can metabolize this compound within their colonic mucosa and liver leading to the production of co-metabolites including p-cresyl sulfate (p-CS) and p-cresyl glucuronide (p-CG). p-Cresol and its co-metabolites are recovered in the circulation mainly conjugated to albumin, but also in their free forms that are excreted in the urine. An increased dietary protein intake raises the amount of p-cresol recovered in the feces and urine, while fecal excretion of p-cresol is diminished by a diet containing undigestible polysaccharides. p-Cresol in excess is genotoxic for colonocytes. In addition, in these cells, this bacterial metabolite decreases mitochondrial oxygen consumption, while increasing the anion superoxide production. In chronic kidney disease (CKD), marked accumulation of p-cresol and p-CS in plasma is measured, and in renal tubular cells, p-cresol and p-CS increase oxidative stress, affect mitochondrial function, and lead to cell death, strongly suggesting that these 2 compounds act as uremic toxins that aggravate CKD progression. p-Cresol and p-CS are also suspected to play a role in the CKD-associated adverse cardiovascular events, since they affect endothelial cell proliferation and migration, decrease the capacity of endothelial wound repair, and increase the senescence of endothelial cells. Finally, the fact that concentration of p-cresol is transiently increased in young autistic children biological fluids, and that intraperitoneal injection of p-cresol in animal models induces some behavioral characteristics observed in the autism spectrum disorders (ASD), raise the view that p-cresol may possibly represent one of the components involved in ASD etiology. Further pre-clinical and clinical studies are obviously needed to determine if the lowering of p-cresol and/or p-CS circulating concentrations, by dietary and/or pharmacological means, would allow, by itself or in combination with other interventions, to improve CKD progression and associated cardiovascular outcomes, as well as some neurological outcomes in children with an early diagnosis of autism.
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Affiliation(s)
- F Blachier
- Université Paris-Saclay, AgroParisTech, INRAE, UMR PNCA, Paris, France.
| | - M Andriamihaja
- Université Paris-Saclay, AgroParisTech, INRAE, UMR PNCA, Paris, France
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21
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Rong Y, Kiang TKL. Characterizations of Human UDP-Glucuronosyltransferase Enzymes in the Conjugation of p-Cresol. Toxicol Sci 2021; 176:285-296. [PMID: 32421801 DOI: 10.1093/toxsci/kfaa072] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
p-Cresol is a uremic toxin that is formed by intestinal microbiota and extensively conjugated by first-pass metabolism. p-Cresol glucuronide exerts various forms of cellular toxicity in vitro and is accumulated in the plasma of subjects with kidney disease, where associations with adverse cardiovascular and renal outcomes are evident. The objective of this study was to determine the contributions of human UDP-glucuronosyltransferase (UGT) enzymes in the formation of p-cresol glucuronide. Utilizing commonly expressed hepatic or renal human recombinant UGTs (ie, hrUGT1A1, 1A3, 1A4, 1A6, 1A7, 1A8, 1A9, 1A10, 2B4, 2B7, 2B10, 2B15, and 2B17), hrUGT1A6 and hrUGT1A9 exhibited the highest catalytic activities in the generation of p-cresol glucuronide. The kinetics of p-cresol glucuronide formation in hrUGT1A6 and pooled human liver microsomes were best described by the Hill equation and in hrUGT1A9 and pooled human kidney microsomes by substrate inhibition. Using inhibitory and selective UGT inhibitors (ie, acetaminophen or amentoflavone for UGT1A6 and niflumic acid for UGT1A9), UGT1A6 was identified the predominant enzyme responsible for p-cresol glucuronide production in pooled human liver (78.4%-81.3% contribution) and kidney (54.3%-62.9%) microsomes, whereas UGT1A9 provided minor contributions (2.8% and 35.5%, respectively). The relative contributions of UGT1A6 (72.6 ± 11.3%, mean ± SD) and UGT1A9 (5.7 ± 4.1%) in individual human liver microsomes from 12 adult donors were highly variable, where an inverse association (R = -.784, p = .003) between UGT1A6 contribution and UGT1A9 probe substrate activity (ie, mycophenolic acid) was evident. Our novel findings provide valuable tools for conducting further mechanistic studies and for designing clinical interventions to mitigate the toxicities associated with p-cresol glucuronide.
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Affiliation(s)
- Yan Rong
- Faculty of Pharmacy and Pharmaceutical Sciences, Katz Group Centre for Pharmacy and Health Research, University of Alberta, Edmonton, Alberta T6G 2E1, Canada
| | - Tony K L Kiang
- Faculty of Pharmacy and Pharmaceutical Sciences, Katz Group Centre for Pharmacy and Health Research, University of Alberta, Edmonton, Alberta T6G 2E1, Canada
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22
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Lu L, Chen X, Liu Y, Yu X. Gut microbiota and bone metabolism. FASEB J 2021; 35:e21740. [PMID: 34143911 DOI: 10.1096/fj.202100451r] [Citation(s) in RCA: 32] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2021] [Revised: 06/03/2021] [Accepted: 06/04/2021] [Indexed: 02/05/2023]
Abstract
Osteoporosis is the most common metabolic skeletal disease. It is characterized by the deterioration of the skeletal microarchitecture and bone loss, leading to ostealgia, and even bone fractures. Accumulating evidence has indicated that there is an inextricable relationship between the gut microbiota (GM) and bone homeostasis involving host-microbiota crosstalk. Any perturbation of the GM can play an initiating and reinforcing role in disrupting the bone remodeling balance during the development of osteoporosis. Although the GM is known to influence bone metabolism, the mechanisms associated with these effects remain unclear. Herein, we review the current knowledge of how the GM affects bone metabolism in health and disease, summarize the correlation between pathogen-associated molecular patterns of GM structural components and bone metabolism, and discuss the potential mechanisms underlying how GM metabolites regulate bone turnover. Deciphering the complicated relationship between the GM and bone health will provide new insights into the prevention and treatment of osteoporosis.
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Affiliation(s)
- Lingyun Lu
- Department of Endocrinology and Metabolism, Laboratory of Endocrinology and Metabolism, Rare Disease Center, West China Hospital, Sichuan University, Chengdu, China.,Department of Integrated Traditional Chinese and Western Medicine, West China Hospital, Sichuan University, Chengdu, China
| | - Xiaoxuan Chen
- State Key Laboratory of Oral Diseases, National Clinical Research Center for Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - Yi Liu
- Department of Rheumatology and Immunology, Rare Disease Center, West China Hospital, Sichuan University, Chengdu, China
| | - Xijie Yu
- Department of Endocrinology and Metabolism, Laboratory of Endocrinology and Metabolism, Rare Disease Center, West China Hospital, Sichuan University, Chengdu, China
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Effects of p-Cresol on Oxidative Stress, Glutathione Depletion, and Necrosis in HepaRG Cells: Comparisons to Other Uremic Toxins and the Role of p-Cresol Glucuronide Formation. Pharmaceutics 2021; 13:pharmaceutics13060857. [PMID: 34207666 PMCID: PMC8228354 DOI: 10.3390/pharmaceutics13060857] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2021] [Revised: 06/03/2021] [Accepted: 06/06/2021] [Indexed: 12/14/2022] Open
Abstract
The toxicological effects of p-cresol have primarily been attributed to its metabolism products; however, very little human data are available in the key organ (i.e., liver) responsible for the generation of these metabolites. Experiments were conducted in HepaRG cells utilizing the following markers of cellular toxicity: 2′-7′-dichlorofluorescein (DCF; oxidative stress) formation, total cellular glutathione (GSH) concentration, and lactate dehydrogenase (LDH; cellular necrosis) release. Concentrations of p-cresol, p-cresol sulfate, and p-cresol glucuronide were determined using validated assays. p-Cresol exposure resulted in concentration- and time-dependent changes in DCF (EC50 = 0.64 ± 0.37 mM at 24 h of exposure) formation, GSH (EC50 = 1.00 ± 0.07 mM) concentration, and LDH (EC50 = 0.85 ± 0.14 mM) release at toxicologically relevant conditions. p-Cresol was also relatively more toxic than 3-carboxy-4-methyl-5-propyl-2-furanpropanoic acid, indole-3-acetic acid, indoxyl sulfate, kynurenic acid, and hippuric acid on all markers. Although the exogenous administration of p-cresol sulfate and p-cresol glucuronide generated high intracellular concentrations of these metabolites, both metabolites were less toxic compared to p-cresol at equal-molar conditions. Moreover, p-cresol glucuronide was the predominant metabolite generated in situ from p-cresol exposure. Selective attenuation of glucuronidation (without affecting p-cresol sulfate formation, while increasing p-cresol accumulation) using independent chemical inhibitors (i.e., 0.75 mM l-borneol, 75 µM amentoflavone, or 100 µM diclofenac) consistently resulted in further increases in LDH release associated with p-cresol exposure (by 28.3 ± 5.3%, 30.0 ± 8.2% or 27.3 ± 6.8%, respectively, compared to p-cresol treatment). These novel data indicated that p-cresol was a relatively potent toxicant, and that glucuronidation was unlikely to be associated with the manifestation of its toxic effects in HepaRG cells.
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24
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Maksimov AY, Balandina SY, Topanov PA, Mashevskaya IV, Chaudhary S. Organic Antifungal Drugs and Targets of Their Action. Curr Top Med Chem 2021; 21:705-736. [PMID: 33423647 DOI: 10.2174/1568026621666210108122622] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2020] [Revised: 08/20/2020] [Accepted: 09/03/2020] [Indexed: 11/22/2022]
Abstract
In recent decades, there has been a significant increase in the number of fungal diseases. This is due to a wide spectrum of action, immunosuppressants and other group drugs. In terms of frequency, rapid spread and globality, fungal infections are approaching acute respiratory infections. Antimycotics are medicinal substances endorsed with fungicidal or fungistatic properties. For the treatment of fungal diseases, several groups of compounds are used that differ in their origin (natural or synthetic), molecular targets and mechanism of action, antifungal effect (fungicidal or fungistatic), indications for use (local or systemic infections), and methods of administration (parenteral, oral, outdoor). Several efforts have been made by various medicinal chemists around the world for the development of antifungal drugs with high efficacy with the least toxicity and maximum selectivity in the area of antifungal chemotherapy. The pharmacokinetic properties of the new antimycotics are also important: the ability to penetrate biological barriers, be absorbed and distributed in tissues and organs, get accumulated in tissues affected by micromycetes, undergo drug metabolism in the intestinal microflora and human organs, and in the kinetics of excretion from the body. There are several ways to search for new effective antimycotics: - Obtaining new derivatives of the already used classes of antimycotics with improved activity properties. - Screening of new chemical classes of synthetic antimycotic compounds. - Screening of natural compounds. - Identification of new unique molecular targets in the fungal cell. - Development of new compositions and dosage forms with effective delivery vehicles. The methods of informatics, bioinformatics, genomics and proteomics were extensively investigated for the development of new antimycotics. These techniques were employed in finding and identification of new molecular proteins in a fungal cell; in the determination of the selectivity of drugprotein interactions, evaluation of drug-drug interactions and synergism of drugs; determination of the structure-activity relationship (SAR) studies; determination of the molecular design of the most active, selective and safer drugs for the humans, animals and plants. In medical applications, the methods of information analysis and pharmacogenomics allow taking into account the individual phenotype of the patient, the level of expression of the targets of antifungal drugs when choosing antifungal agents and their dosage. This review article incorporates some of the most significant studies covering the basic structures and approaches for the synthesis of antifungal drugs and the directions for their further development.
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Affiliation(s)
- Alexander Yu Maksimov
- Department of Pharmacy and Pharmacology, Faculty of Chemistry, Perm State University, Perm 614990, Russian Federation
| | - Svetlana Yu Balandina
- Department of Pharmacy and Pharmacology, Faculty of Chemistry, Perm State University, Perm 614990, Russian Federation
| | - Pavel A Topanov
- Department of Pharmacy and Pharmacology, Faculty of Chemistry, Perm State University, Perm 614990, Russian Federation
| | - Irina V Mashevskaya
- Department of Pharmacy and Pharmacology, Faculty of Chemistry, Perm State University, Perm 614990, Russian Federation
| | - Sandeep Chaudhary
- Laboratory of Organic and Medicinal Chemistry (OMC lab), Department of Chemistry, Malaviya National Institute of Technology Jaipur, Jawaharlal Nehru Marg, Jaipur 302017, India
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25
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Thrombolome and Its Emerging Role in Chronic Kidney Diseases. Toxins (Basel) 2021; 13:toxins13030223. [PMID: 33803899 PMCID: PMC8003125 DOI: 10.3390/toxins13030223] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2021] [Revised: 03/14/2021] [Accepted: 03/15/2021] [Indexed: 12/25/2022] Open
Abstract
Patients with chronic kidney disease (CKD) are at an increased risk of thromboembolic complications, including myocardial infarction, stroke, deep vein thrombosis, and pulmonary embolism. These complications lead to increased mortality. Evidence points to the key role of CKD-associated dysbiosis and its effect via the generation of gut microbial metabolites in inducing the prothrombotic phenotype. This phenomenon is known as thrombolome, a panel of intestinal bacteria-derived uremic toxins that enhance thrombosis via increased tissue factor expression, platelet hyperactivity, microparticles release, and endothelial dysfunction. This review discusses the role of uremic toxins derived from gut-microbiota metabolism of dietary tryptophan (indoxyl sulfate (IS), indole-3-acetic acid (IAA), kynurenine (KYN)), phenylalanine/tyrosine (p-cresol sulfate (PCS), p-cresol glucuronide (PCG), phenylacetylglutamine (PAGln)) and choline/phosphatidylcholine (trimethylamine N-oxide (TMAO)) in spontaneously induced thrombosis. The increase in the generation of gut microbial uremic toxins, the activation of aryl hydrocarbon (AhRs) and platelet adrenergic (ARs) receptors, and the nuclear factor kappa B (NF-κB) signaling pathway can serve as potential targets during the prevention of thromboembolic events. They can also help create a new therapeutic approach in the CKD population.
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26
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Jerez-Morales A, Merino JS, Díaz-Castillo ST, Smith CT, Fuentealba J, Bernasconi H, Echeverría G, García-Cancino A. The Administration of the Synbiotic Lactobacillus bulgaricus 6c3 Strain, Inulin and Fructooligosaccharide Decreases the Concentrations of Indoxyl Sulfate and Kidney Damage in a Rat Model. Toxins (Basel) 2021; 13:192. [PMID: 33800029 PMCID: PMC7999732 DOI: 10.3390/toxins13030192] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2020] [Revised: 02/13/2021] [Accepted: 02/16/2021] [Indexed: 12/12/2022] Open
Abstract
Indoxyl sulfate (IS) is involved in the progression of chronic kidney disease (CKD) and in its cardiovascular complications. One of the approaches proposed to decrease IS is the administration of synbiotics. This work aimed to search for a probiotic strain capable to decrease serum IS levels and mix it with two prebiotics (inulin and fructooligosaccharide (FOS)) to produce a putative synbiotic and test it in a rat CKD model. Two groups of Sprague-Dawley rats were nephrectomized. One group (Lac) received the mixture for 16 weeks in drinking water and the other no (Nef). A control group (C) included sham-nephrectomized rats. Serum creatinine and IS concentrations were measured using high-performance liquid chromatography with diode array detector (HPLC-DAD). Optical microscopy and two-photon excitation microscopy was used to study kidney and heart samples. The Lac group, which received the synbiotic, reduced IS by 0.8% while the Nef group increased it by 38.8%. Histological analysis of kidneys showed that the Lac group increased fibrotic areas by 12% and the Nef group did it by 25%. The synbiotic did not reduce cardiac fibrosis. Therefore, the putative synbiotic showed that function reducing IS and the progression of CKD in a rat model, but no heart protection was observed.
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Affiliation(s)
- Alonso Jerez-Morales
- Laboratory of Bacterial Pathogenicity, Faculty of Biological Sciences, Universidad de Concepción, 4070386 Concepción, Chile; (A.J.-M.); (C.T.S.)
- Pasteur Laboratory, Research and Development Department, 4030635 Concepción, Chile; (S.T.D.-C.); (H.B.)
| | - José S. Merino
- Faculty of Veterinary and Agronomy, University of the Americas, 4070254 Concepción, Chile;
| | - Sindy T. Díaz-Castillo
- Pasteur Laboratory, Research and Development Department, 4030635 Concepción, Chile; (S.T.D.-C.); (H.B.)
| | - Carlos T. Smith
- Laboratory of Bacterial Pathogenicity, Faculty of Biological Sciences, Universidad de Concepción, 4070386 Concepción, Chile; (A.J.-M.); (C.T.S.)
| | - Jorge Fuentealba
- Laboratory of Screening of Neuroactive Compounds, Universidad de Concepción, 4070386 Concepción, Chile;
| | - Humberto Bernasconi
- Pasteur Laboratory, Research and Development Department, 4030635 Concepción, Chile; (S.T.D.-C.); (H.B.)
| | | | - Apolinaria García-Cancino
- Laboratory of Bacterial Pathogenicity, Faculty of Biological Sciences, Universidad de Concepción, 4070386 Concepción, Chile; (A.J.-M.); (C.T.S.)
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27
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Chen Y, Zelnick LR, Wang K, Katz R, Hoofnagle AN, Becker JO, Hsu CY, Go AS, Feldman HI, Mehta RC, Lash JP, Waikar SS, Hamm L, Chen J, Shafi T, Kestenbaum BR. Association of tubular solute clearances with the glomerular filtration rate and complications of chronic kidney disease: the Chronic Renal Insufficiency Cohort study. Nephrol Dial Transplant 2020; 36:gfaa057. [PMID: 33330914 PMCID: PMC8237987 DOI: 10.1093/ndt/gfaa057] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2019] [Accepted: 02/25/2020] [Indexed: 12/13/2022] Open
Abstract
BACKGROUND The secretion of organic solutes by the proximal tubules is an essential intrinsic kidney function. The degree to which secretory solute clearance corresponds with the glomerular filtration rate (GFR) and potential metabolic implications of net secretory clearance are largely unknown. METHODS We evaluated 1240 participants with chronic kidney disease (CKD) from the multicenter Chronic Renal Insufficiency Cohort (CRIC) Study. We used targeted mass-spectrometry to quantify candidate secretory solutes in paired 24-h urine and plasma samples. CRIC study personnel measured GFR using 125I-iothalamate clearance (iGFR). We used correlation and linear regression to determine cross-sectional associations of secretory clearances with iGFR and common metabolic complications of CKD. RESULTS Correlations between iGFR and secretory solute clearances ranged from ρ = +0.30 for hippurate to ρ = +0.58 for kynurenic acid. Lower net clearances of most secretory solutes were associated with higher serum concentrations of parathyroid hormone (PTH), triglycerides and uric acid. Each 50% lower kynurenic acid clearance was associated with a 21% higher serum PTH concentration [95% confidence interval (CI) 15-26%] and a 10% higher serum triglyceride concentration (95% CI 5-16%) after adjustment for iGFR, albuminuria and other potential confounders. Secretory solute clearances were not associated with statistically or clinically meaningful differences in serum calcium, phosphate, hemoglobin or bicarbonate concentrations. CONCLUSIONS Tubular secretory clearances are modestly correlated with measured GFR among adult patients with CKD. Lower net secretory clearances are associated with selected metabolic complications independent of GFR and albuminuria, suggesting potential clinical and biological relevance.
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Affiliation(s)
- Yan Chen
- Department of Epidemiology, University of Washington, Seattle, WA, USA
- Kidney Research Institute, Seattle, WA, USA
| | - Leila R Zelnick
- Kidney Research Institute, Seattle, WA, USA
- Department of Medicine, Division of Nephrology, University of Washington, Seattle, WA, USA
| | - Ke Wang
- Kidney Research Institute, Seattle, WA, USA
- Department of Medicine, Division of Nephrology, University of Washington, Seattle, WA, USA
| | - Ronit Katz
- Kidney Research Institute, Seattle, WA, USA
- Department of Medicine, Division of Nephrology, University of Washington, Seattle, WA, USA
| | - Andrew N Hoofnagle
- Kidney Research Institute, Seattle, WA, USA
- Department of Laboratory Medicine, University of Washington, Seattle, WA, USA
| | - Jessica O Becker
- Department of Laboratory Medicine, University of Washington, Seattle, WA, USA
| | - Chi-Yuan Hsu
- Department of Medicine, Division of Nephrology, University of California San Francisco, San Francisco, CA, USA
| | - Alan S Go
- Division of Research, Kaiser Permanente Northern California, Oakland, CA, USA
| | - Harold I Feldman
- Department of Biostatistics, Epidemiology and Informatics, University of Pennsylvania, Philadelphia, PA, USA
- Center for Clinical Epidemiology and Biostatistics, University of Pennsylvania, Philadelphia, PA, USA
| | - Rupal C Mehta
- Department of Medicine, Division of Nephrology and Hypertension, Jesse Brown Veterans Administration Medical Center & Northwestern University, Chicago, IL, USA
| | - James P Lash
- Department of Medicine, Division of Nephrology, University of Illinois at Chicago, Chicago, IL, USA
| | | | - L Hamm
- Division of Nephrology and Hypertension, Tulane University Department of Medicine, New Orleans, LA, USA
| | - Jing Chen
- Division of Nephrology and Hypertension, Tulane University Department of Medicine, New Orleans, LA, USA
| | - Tariq Shafi
- Department of Medicine, Division of Nephrology, University of Mississippi Medical Center, Jackson, MS, USA
| | - Bryan R Kestenbaum
- Kidney Research Institute, Seattle, WA, USA
- Department of Medicine, Division of Nephrology, University of Washington, Seattle, WA, USA
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28
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Vijayasarathy M, Kiran GK, Balaji S, Jabastin J, Bruntha Devi P, Brindha Priyadarisini V. In Vitro Detoxification Studies of p-Cresol by Intestinal Bacteria Isolated from Human Feces. Curr Microbiol 2020; 77:3000-3012. [DOI: 10.1007/s00284-020-02124-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2019] [Accepted: 07/09/2020] [Indexed: 10/23/2022]
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29
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Koppe L, Soulage CO. Preservation of residual kidney function to reduce non-urea solutes toxicity in haemodialysis. Nephrol Dial Transplant 2020; 35:733-736. [PMID: 31711183 DOI: 10.1093/ndt/gfz224] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2019] [Accepted: 10/04/2019] [Indexed: 12/24/2022] Open
Affiliation(s)
- Laetitia Koppe
- Department of Nephrology, Hospices Civils de Lyon, Centre Hospitalier Lyon-Sud, Pierre-Bénite, France.,Univ-Lyon, CarMeN lab, INSA Lyon, INSERM U1060, INRA, Université Claude Bernard Lyon 1, Villeurbanne, France
| | - Christophe O Soulage
- Univ-Lyon, CarMeN lab, INSA Lyon, INSERM U1060, INRA, Université Claude Bernard Lyon 1, Villeurbanne, France
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30
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Mercer KE, Ten Have GAM, Pack L, Lan R, Deutz NEP, Adams SH, Piccolo BD. Net release and uptake of xenometabolites across intestinal, hepatic, muscle, and renal tissue beds in healthy conscious pigs. Am J Physiol Gastrointest Liver Physiol 2020; 319:G133-G141. [PMID: 32538141 PMCID: PMC7500263 DOI: 10.1152/ajpgi.00153.2020] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Xenometabolites from microbial and plant sources are thought to confer beneficial as well as deleterious effects on host physiology. Studies determining absorption and tissue uptake of xenometabolites are limited. We utilized a conscious catheterized pig model to evaluate interorgan flux of annotated known and suspected xenometabolites, derivatives, and bile acids. Female pigs (n = 12, 2-3 mo old, 25.6 ± 2.2 kg) had surgically implanted catheters across portal-drained viscera (PDV), splanchnic compartment (SPL), liver, kidney, and hindquarter muscle. Overnight-fasted arterial and venous plasma was collected simultaneously in a conscious state and stored at -80°C. Thawed samples were analyzed by liquid chromatography-mass spectrometry. Plasma flow was determined with para-aminohippuric acid dilution technology and used to calculate net organ balance for each metabolite. Significant organ uptake or release was determined if net balance differed from zero. A total of 48 metabolites were identified in plasma, and 31 of these had at least one tissue with a significant net release or uptake. All bile acids, indole-3-acetic acid, indole-3-arylic acid, and hydrocinnamic acid were released from the intestine and taken up by the liver. Indole-3-carboxaldehyde, p-cresol glucuronide, 4-hydroxyphenyllactic acid, dodecanendioic acid, and phenylacetylglycine were also released from the intestines. Liver or kidney uptake was noted for indole-3-acetylglycine, p-cresol glucuronide, atrolactic acid, and dodecanedioic acid. Indole-3-carboxaldehyde, atrolactic acid, and dodecanedioic acids showed net release from skeletal muscle. The results confirm gastrointestinal origins for several known xenometabolites in an in vivo overnight-fasted conscious pig model, whereas nongut net release of other putative xenometabolites suggests a more complex metabolism.NEW & NOTEWORTHY Xenometabolites from microbe origins influence host health and disease, but absorption and tissue uptake of these metabolites remain speculative. Results herein are the first to demonstrate in vivo organ uptake and release of these metabolites. We used a conscious catheterized pig model to confirm gastrointestinal origins for several xenometabolites (e.g., indolic compounds, 4-hydroxyphenyllactic acid, dodecanendioic acid, and phenylacetylgycine). Liver and kidney were major sites for xenometabolite uptake, likely highlighting liver conjugation metabolism and renal excretion.
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Affiliation(s)
- Kelly E. Mercer
- 1Arkansas Children’s Nutrition Center, Little Rock, Arkansas,2Department of Pediatrics, University of Arkansas for Medical Sciences, Little Rock, Arkansas
| | - Gabriella A. M. Ten Have
- 3Center for Translational Research in Aging and Longevity, Department of Health and Kinesiology, Texas A & M University, College Station, Texas
| | - Lindsay Pack
- 1Arkansas Children’s Nutrition Center, Little Rock, Arkansas
| | - Renny Lan
- 1Arkansas Children’s Nutrition Center, Little Rock, Arkansas,2Department of Pediatrics, University of Arkansas for Medical Sciences, Little Rock, Arkansas
| | - Nicolaas E. P. Deutz
- 3Center for Translational Research in Aging and Longevity, Department of Health and Kinesiology, Texas A & M University, College Station, Texas
| | - Sean H. Adams
- 1Arkansas Children’s Nutrition Center, Little Rock, Arkansas,2Department of Pediatrics, University of Arkansas for Medical Sciences, Little Rock, Arkansas
| | - Brian D. Piccolo
- 1Arkansas Children’s Nutrition Center, Little Rock, Arkansas,2Department of Pediatrics, University of Arkansas for Medical Sciences, Little Rock, Arkansas
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Evenepoel P, Dejongh S, Verbeke K, Meijers B. The Role of Gut Dysbiosis in the Bone-Vascular Axis in Chronic Kidney Disease. Toxins (Basel) 2020; 12:toxins12050285. [PMID: 32365480 PMCID: PMC7290823 DOI: 10.3390/toxins12050285] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2020] [Revised: 04/15/2020] [Accepted: 04/16/2020] [Indexed: 12/12/2022] Open
Abstract
Patients with chronic kidney disease (CKD) are at increased risk of bone mineral density loss and vascular calcification. Bone demineralization and vascular mineralization often concur in CKD, similar to what observed in the general population. This contradictory association is commonly referred to as the 'calcification paradox' or the bone-vascular axis. Mounting evidence indicates that CKD-associated gut dysbiosis may be involved in the pathogenesis of the bone-vascular axis. A disrupted intestinal barrier function, a metabolic shift from a predominant saccharolytic to a proteolytic fermentation pattern, and a decreased generation of vitamin K may, alone or in concert, drive a vascular and skeletal pathobiology in CKD patients. A better understanding of the role of gut dysbiosis in the bone-vascular axis may open avenues for novel therapeutics, including nutriceuticals.
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Affiliation(s)
- Pieter Evenepoel
- Laboratory of Nephrology, Department of Immunology and Microbiology, KU Leuven—University of Leuven, B-3000 Leuven, Belgium
- Department of Nephrology and Renal Transplantation, University Hospitals Leuven, B-3000 Leuven, Belgium
- Correspondence: ; Tel.: +32-16-344591; Fax: +32-16-344599
| | - Sander Dejongh
- Laboratory of Nephrology, Department of Immunology and Microbiology, KU Leuven—University of Leuven, B-3000 Leuven, Belgium
- Department of Nephrology and Renal Transplantation, University Hospitals Leuven, B-3000 Leuven, Belgium
| | - Kristin Verbeke
- Translational Research Center for Gastrointestinal Disorders (TARGID), KU Leuven—University of Leuven, B-3000 Leuven, Belgium
| | - Bjorn Meijers
- Laboratory of Nephrology, Department of Immunology and Microbiology, KU Leuven—University of Leuven, B-3000 Leuven, Belgium
- Department of Nephrology and Renal Transplantation, University Hospitals Leuven, B-3000 Leuven, Belgium
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Glorieux G, Gryp T, Perna A. Gut-Derived Metabolites and Their Role in Immune Dysfunction in Chronic Kidney Disease. Toxins (Basel) 2020; 12:toxins12040245. [PMID: 32290429 PMCID: PMC7232434 DOI: 10.3390/toxins12040245] [Citation(s) in RCA: 37] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2020] [Revised: 04/08/2020] [Accepted: 04/10/2020] [Indexed: 02/07/2023] Open
Abstract
Several of the uremic toxins, which are difficult to remove by dialysis, originate from the gut bacterial metabolism. This opens opportunities for novel targets trying to decrease circulating levels of these toxins and their pathophysiological effects. The current review focuses on immunomodulatory effects of these toxins both at their side of origin and in the circulation. In the gut end products of the bacterial metabolism such as p-cresol, trimethylamine and H2S affect the intestinal barrier structure and function while in the circulation the related uremic toxins stimulate cells of the immune system. Both conditions contribute to the pro-inflammatory status of patients with chronic kidney disease (CKD). Generation and/or absorption of these toxin precursors could be targeted to decrease plasma levels of their respective uremic toxins and to reduce micro-inflammation in CKD.
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Affiliation(s)
- Griet Glorieux
- Nephrology Division, Ghent University Hospital and Ghent University, 9000 Ghent, Belgium;
- Correspondence: ; Tel.: +32-9-3324511
| | - Tessa Gryp
- Nephrology Division, Ghent University Hospital and Ghent University, 9000 Ghent, Belgium;
| | - Alessandra Perna
- First Division of Nephrology, Department of Translational Medical Sciences, School of Medicine, University of Campania “Luigi Vanvitelli”, 80131 Naples, Italy;
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33
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Protein-Bound Uremic Toxins in Hemodialysis Patients Relate to Residual Kidney Function, Are Not Influenced by Convective Transport, and Do Not Relate to Outcome. Toxins (Basel) 2020; 12:toxins12040234. [PMID: 32272776 PMCID: PMC7232478 DOI: 10.3390/toxins12040234] [Citation(s) in RCA: 32] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2020] [Revised: 03/31/2020] [Accepted: 04/05/2020] [Indexed: 01/13/2023] Open
Abstract
Protein-bound uremic toxins (PBUTs) are predominantly excreted by renal tubular secretion and hardly removed by traditional hemodialysis (HD). Accumulation of PBUTs is proposed to contribute to the increased morbidity and mortality of patients with end-stage kidney disease (ESKD). Preserved PBUT excretion in patients with residual kidney function (RKF) and/or increased PBUT clearance with improved dialysis techniques might improve the prognosis of patients with ESKD. The aims of this study are to explore determinants of PBUTs in HD patients, and investigate whether hemodiafiltration (HDF) lowers PBUT plasma concentrations, and whether PBUTs are related to the outcome. Predialysis total plasma concentrations of kynurenine, kynurenic acid, indoxyl sulfate, indole-3-acetic acid, p-cresyl sulfate, p-cresyl glucuronide, and hippuric acid were measured by UHPLC-MS at baseline and after 6 months of follow-up in the first 80 patients participating in the CONvective TRAnsport Study (CONTRAST), a randomized controlled trial that compared the effects of online HDF versus low-flux HD on all-cause mortality and new cardiovascular events. RKF was inversely related to kynurenic acid (p < 0.001), indoxyl sulfate (p = 0.001), indole-3-acetic acid (p = 0.024), p-cresyl glucuronide (p = 0.004) and hippuric acid (p < 0.001) plasma concentrations. Only indoxyl sulfate decreased by 8.0% (−15.3 to 34.6) in patients treated with HDF and increased by 11.9% (−15.4 to 31.9) in HD patients after 6 months of follow-up (HDF vs. HD: p = 0.045). No independent associations were found between PBUT plasma concentrations and either risk of all-cause mortality or new cardiovascular events. In summary, in the current population, RKF is an important determinant of PBUT plasma concentrations in HD patients. The addition of convective transport did not consistently decrease PBUT plasma concentrations and no relation was found between PBUTs and cardiovascular endpoints.
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Gryp T, De Paepe K, Vanholder R, Kerckhof FM, Van Biesen W, Van de Wiele T, Verbeke F, Speeckaert M, Joossens M, Couttenye MM, Vaneechoutte M, Glorieux G. Gut microbiota generation of protein-bound uremic toxins and related metabolites is not altered at different stages of chronic kidney disease. Kidney Int 2020; 97:1230-1242. [PMID: 32317112 DOI: 10.1016/j.kint.2020.01.028] [Citation(s) in RCA: 114] [Impact Index Per Article: 28.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2019] [Revised: 01/17/2020] [Accepted: 01/24/2020] [Indexed: 01/06/2023]
Abstract
Chronic kidney disease (CKD) is characterized by accumulation of protein-bound uremic toxins such as p-cresyl sulfate, p-cresyl glucuronide, indoxyl sulfate and indole-3-acetic acid, which originate in the gut. Intestinal bacteria metabolize aromatic amino acids into p-cresol and indole, (further conjugated in the colon mucosa and liver) and indole-3-acetic acid. Here we measured fecal, plasma and urine metabolite concentrations; the contribution of gut bacterial generation to plasma protein-bound uremic toxins accumulation; and influx into the gut of circulating protein-bound uremic toxins at different stages of CKD. Feces, blood and urine were collected from 14 control individuals and 141 patients with CKD. Solutes were quantified by ultra-high performance liquid chromatography. To assess the rate of bacterial generation of p-cresol, indole and indole-3-acetic acid, fecal samples were cultured ex vivo. With CKD progression, an increase in protein-bound uremic toxins levels was observed in plasma, whereas the levels of these toxins and their precursors remained the same in feces and urine. Anaerobic culture of fecal samples showed no difference in ex vivo p-cresol, indole and indole-3-acetic acid generation. Therefore, differences in plasma protein-bound uremic toxins levels between different CKD stages cannot be explained by differences in bacterial generation rates in the gut, suggesting retention due to impaired kidney function as the main contributor to their increased plasma levels. Thus, as fractional clearance decreased with the progression of CKD, tubular clearance appeared to be more affected than the glomerular filtration rate, and there was no net increase in protein-bound uremic toxins influx into the gut lumen with increased plasma levels.
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Affiliation(s)
- Tessa Gryp
- Department of Internal Medicine and Pediatrics, Nephrology Section, Ghent University Hospital, Ghent, Belgium; Department of Diagnostic Sciences, Laboratory Bacteriology Research, Ghent University, Ghent, Belgium; Department of Microbiology, Immunology and Transplantation, Molecular Microbiology-Microbiome Research Lab, KU Leuven, Leuven, Belgium.
| | - Kim De Paepe
- Department of Biotechnology, Center for Microbial Ecology and Technology, Ghent University, Ghent, Belgium
| | - Raymond Vanholder
- Department of Internal Medicine and Pediatrics, Nephrology Section, Ghent University Hospital, Ghent, Belgium
| | - Frederiek-Maarten Kerckhof
- Department of Biotechnology, Center for Microbial Ecology and Technology, Ghent University, Ghent, Belgium
| | - Wim Van Biesen
- Department of Internal Medicine and Pediatrics, Nephrology Section, Ghent University Hospital, Ghent, Belgium
| | - Tom Van de Wiele
- Department of Biotechnology, Center for Microbial Ecology and Technology, Ghent University, Ghent, Belgium
| | - Francis Verbeke
- 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
| | - Marie Joossens
- Department of Microbiology, Immunology and Transplantation, Molecular Microbiology-Microbiome Research Lab, KU Leuven, Leuven, Belgium
| | | | - Mario Vaneechoutte
- Department of Diagnostic Sciences, Laboratory Bacteriology Research, Ghent University, Ghent, Belgium
| | - Griet Glorieux
- Department of Internal Medicine and Pediatrics, Nephrology Section, Ghent University Hospital, Ghent, Belgium
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Comparison of 2 Serum-Free Light-Chain Assays in CKD Patients. Kidney Int Rep 2020; 5:627-631. [PMID: 32405584 PMCID: PMC7210599 DOI: 10.1016/j.ekir.2020.01.019] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2019] [Revised: 01/10/2020] [Accepted: 01/23/2020] [Indexed: 11/23/2022] Open
Abstract
Introduction Quantification of serum-free light chains (FLCs) is important in the diagnosis and monitoring of paraprotein-related diseases. There are currently 2 FLC assays available: the Freelite assay (Binding Site) and the N Latex assay (Siemens). There is emerging evidence that these assays give different results, but it is not established how kidney dysfunction affects these assays differently. Methods In this study, we measured and compared serum FLCs in patients with mild-to-moderate chronic kidney disease (CKD) using both assays. Results Although κ FLCs are higher by Freelite, λ FLCs are higher by N Latex. Both κ and λ FLCs correlate inversely with estimated glomerular filtration rate (eGFR) in the 2 assays, but this effect is more pronounced in λ-free light-chain measurement by N Latex. Consequently, although the κ/λ ratio by Freelite is inversely correlated by eGFR, the κ/λ ratio by N Latex is positively correlated with eGFR. Conclusion Our results clearly demonstrate that the 2 available FLC assays cannot be used interchangeably in patients with CKD.
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Snelson M, Biruete A, McFarlane C, Campbell K. A Renal Clinician's Guide to the Gut Microbiota. J Ren Nutr 2020; 30:384-395. [PMID: 31928802 DOI: 10.1053/j.jrn.2019.11.002] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2019] [Revised: 10/16/2019] [Accepted: 11/09/2019] [Indexed: 02/07/2023] Open
Abstract
It is increasingly recognized that the gut microbiota plays a role in the progression of chronic diseases and that diet may confer health benefits by altering the gut microbiota composition. This is of particular relevance for chronic kidney disease (CKD), as the gut is a source of uremic retention solutes, which accumulate as a result of impaired kidney function and can exert nephrotoxic and other harmful effects. Kidney dysfunction is also associated with changes in the composition of the gut microbiota and the gastrointestinal tract. Diet modulates the gut microbiota, and there is much interest in the use of prebiotics, probiotics, and synbiotics as dietary therapies in CKD, as well as dietary patterns that beneficially alter the microbiota. This review provides an overview of the gut microbiota and its measurement, its relevance in the context of CKD, and the current state of knowledge regarding dietary manipulation of the microbiota.
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Affiliation(s)
- Matthew Snelson
- Department of Diabetes, Central Clinical School, Monash University, Melbourne, Australia.
| | - Annabel Biruete
- Division of Nephrology, Indiana University School of Medicine, Indianapolis, Indiana
| | - Catherine McFarlane
- School of Medicine, University of Queensland, Brisbane, Queensland, Australia; Renal Department, Sunshine Coast University Hospital, Birtinya, Queensland, Australia
| | - Katrina Campbell
- Menzies Health Institute Queensland, Griffith University, Nathan, Queensland, Australia; Allied Health Services, Metro North Hospital and Health Service, Herston, Queensland, Australia
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Charcoal for the management of pruritus and uremic toxins in patients with chronic kidney disease. Curr Opin Nephrol Hypertens 2020; 29:71-79. [DOI: 10.1097/mnh.0000000000000567] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
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Chung S, Barnes JL, Astroth KS. Gastrointestinal Microbiota in Patients with Chronic Kidney Disease: A Systematic Review. Adv Nutr 2019; 10:888-901. [PMID: 31165878 PMCID: PMC6743837 DOI: 10.1093/advances/nmz028] [Citation(s) in RCA: 36] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2018] [Revised: 01/02/2019] [Accepted: 02/26/2019] [Indexed: 01/08/2023] Open
Abstract
Emerging evidence suggests that gastrointestinal (GI) microbiota dysbiosis is associated with chronic kidney disease (CKD) and metabolite concentrations. The purpose of this systematic review was to evaluate and contextualize the research characterizing GI microbiota in patients with CKD. We searched for full-text, peer-reviewed, English studies in PubMed, Cumulative Index to Nursing and Allied Health Literature, Web of Science, and Google Scholar using a combination of MeSH terms and keywords. Eleven of the 20 studies examined GI microbiota in patients with CKD, and 9 studies focused on the effect of interventions on GI microbiota or metabolites. Available data characterizing GI microbiota in patients with CKD suggest a decline in saccharolytic bacteria and an increase in fermenters of nitrogen-containing compounds, serving as a source for circulating uremic toxins. However, studies examined limited sets of predetermined microbes, which do not reflect the entire GI microbial community and its influence on host physiology. We recommend further studies examining the entire microbial community and the potential role in regulating host physiology in CKD.
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Affiliation(s)
- SeonYoon Chung
- Organizational Systems and Adult Health Department, University of Maryland School of Nursing, Baltimore, MD
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KAWASE T, KAWAKAMI K, HARADA K, CHONAN O, TSUKAHARA T. Simultaneous Analysis of Glucuronyl- and Sulpho-Conjugates of Intestinal Putrefactive Compounds in Human Urine by Ultra-Performance Liquid Chromatography Tandem Mass Spectrometry. CHROMATOGRAPHY 2019. [DOI: 10.15583/jpchrom.2018.017] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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Development of the LC-MS/MS method for determining the p-cresol level in plasma. J Pharm Biomed Anal 2019; 167:149-154. [PMID: 30772758 DOI: 10.1016/j.jpba.2019.01.041] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2018] [Revised: 01/12/2019] [Accepted: 01/25/2019] [Indexed: 01/22/2023]
Abstract
p-Cresol is a protein-bound uremic retention solute that originates in the intestine through bacterial metabolism and accumulates throughout the body in case of kidney failure. To date, there has been no method to analyze unconjugated p-cresol concentration in the blood with a limit of detection lower than 75 pg. Thus, the aim of this study was to develop and validate a novel liquid chromatography-tandem mass spectrometry method for the determination of unconjugated p-cresol in plasma with a lower detection limit than what has been determined using previously described methods. Sample preparation included derivatization of p-cresol with dansyl chloride (derivatization reagent) showed to be a better approach to analyze the compound. The method optimization involved various pH, time of the reaction, and concentration of derivatization reagent. The validation process was performed according to the procedures prescribed by the European Medicines Agency. All analyzed validation criteria were fulfilled. The novel validated method was applied to compare the level of p-cresol in patients with chronic renal failure before and after dialysis (n = 24). Additionally, the concentration of p-cresol was determined in patients with multiple organ dysfunction syndrome (n = 23). The established method can be used for determination of p-cresol in the plasma in further clinical research.
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Liu Y, Liu Z, Wei M, Hu M, Yue K, Bi R, Zhai S, Pi Z, Song F, Liu Z. Pharmacodynamic and urinary metabolomics studies on the mechanism of Schisandra polysaccharide in the treatment of Alzheimer's disease. Food Funct 2019; 10:432-447. [DOI: 10.1039/c8fo02067a] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
This study was designed to investigate the antagonism of SCP in Aβ25–35-induced AD rats by intervening in neurotransmitters and metabolites.
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Affiliation(s)
- Yuanyuan Liu
- State Key Laboratory of Electroanalytical Chemistry
- National Center of Mass Spectrometry in Changchun
- Jilin Province Key Laboratory of Chinese Medicine Chemistry and Mass Spectrometry
- Changchun Institute of Applied Chemistry
- Chinese Academy of Sciences
| | - Zhongying Liu
- School of Pharmaceutical Sciences
- Jilin University
- Changchun 130021
- China
| | - Mengying Wei
- School of Pharmaceutical Sciences
- Jilin University
- Changchun 130021
- China
| | - Mingxin Hu
- School of Pharmaceutical Sciences
- Jilin University
- Changchun 130021
- China
| | - Kexin Yue
- School of Pharmaceutical Sciences
- Jilin University
- Changchun 130021
- China
| | - Rongbing Bi
- Institute of special animal and plant sciences of CAAS
- Changchun 130112
- China
| | - Shan Zhai
- School of Pharmaceutical Sciences
- Jilin University
- Changchun 130021
- China
| | - Zifeng Pi
- State Key Laboratory of Electroanalytical Chemistry
- National Center of Mass Spectrometry in Changchun
- Jilin Province Key Laboratory of Chinese Medicine Chemistry and Mass Spectrometry
- Changchun Institute of Applied Chemistry
- Chinese Academy of Sciences
| | - Fengrui Song
- State Key Laboratory of Electroanalytical Chemistry
- National Center of Mass Spectrometry in Changchun
- Jilin Province Key Laboratory of Chinese Medicine Chemistry and Mass Spectrometry
- Changchun Institute of Applied Chemistry
- Chinese Academy of Sciences
| | - Zhiqiang Liu
- State Key Laboratory of Electroanalytical Chemistry
- National Center of Mass Spectrometry in Changchun
- Jilin Province Key Laboratory of Chinese Medicine Chemistry and Mass Spectrometry
- Changchun Institute of Applied Chemistry
- Chinese Academy of Sciences
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Diagnostic meaning of blood p-cresol concentration in forensic autopsy cases. Leg Med (Tokyo) 2018; 34:27-35. [PMID: 30103078 DOI: 10.1016/j.legalmed.2018.08.003] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2018] [Revised: 08/01/2018] [Accepted: 08/05/2018] [Indexed: 11/20/2022]
Abstract
In some forensic autopsy cases there are high concentrations of p-cresol in the blood. In vivo, p-cresol is the only isomer yielded by intestinal bacteria and is excreted into urine. We investigated the diagnostic meaning of p-cresol in the blood of forensic autopsy cases. Blood samples from 110 autopsy cases within 48 h of the postmortem interval (PMI) and 10 healthy adults were examined. Blood with p-cresol-d8 as an internal standard was analyzed using a GC-MS/MS method. Using acid and heat deproteinization, free (F) and conjugated (non-protein bound: C; protein bound: PC) p-cresol were individually analyzed. The p-cresol concentrations were 1.39 ± 0.86 µg/ml [mean ± SD] and 1.18 (0.19-18.80) µg/ml [median (range)] in healthy adults and autopsy cases, respectively. The p-cresol showed no significant relationship to age, sex, fasting duration, survival duration, or PMI. No significant differences were found between causes of death. Significantly higher levels of C p-cresol were found in cases with atherosclerosis in the basilar or renal arteries, or stenosis in the coronary artery. Significantly higher levels of p-cresol except F were found in cases with hyalinosis of the kidney. Cases with low BMI also showed significantly higher p-cresol concentrations. The 22 cases of abnormally high total p-cresol were investigated. It was considered that high concentrations of p-cresol could be an indicator of certain diseases and physical conditions that effect the production, absorption, metabolism, circulation, and excretion of p-cresol. Measuring the levels of p-cresol may provide valuable information about the antemortem physical conditions.
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Intestinal Barrier Function in Chronic Kidney Disease. Toxins (Basel) 2018; 10:toxins10070298. [PMID: 30029474 PMCID: PMC6071212 DOI: 10.3390/toxins10070298] [Citation(s) in RCA: 53] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2018] [Revised: 07/16/2018] [Accepted: 07/18/2018] [Indexed: 12/13/2022] Open
Abstract
The kidneys are key contributors to body homeostasis, by virtue of controlled excretion of excessive fluid, electrolytes, and toxic waste products. The syndrome of uremia equals the altered physiology due to irreversible loss of kidney function that is left uncorrected for, despite therapeutic intervention(s). The intestines and its microbial content are prime contributors to this syndrome. The intestinal barrier separates the self (or the so-called “milieu intérior”) from the environment. In the large intestine, the intestinal barrier keeps apart human physiology and the microbiota. The enterocytes and the extracellular mucin layer functions form a complex multilayered structure, facilitating complex bidirectional metabolic and immunological crosstalk. The current review focuses on the intestinal barrier in chronic kidney disease (CKD). Loss of kidney function results in structural and functional alterations of the intestinal barrier, contribution to the syndrome of uremia.
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Castillo-Rodriguez E, Fernandez-Prado R, Esteras R, Perez-Gomez MV, Gracia-Iguacel C, Fernandez-Fernandez B, Kanbay M, Tejedor A, Lazaro A, Ruiz-Ortega M, Gonzalez-Parra E, Sanz AB, Ortiz A, Sanchez-Niño MD. Impact of Altered Intestinal Microbiota on Chronic Kidney Disease Progression. Toxins (Basel) 2018; 10:toxins10070300. [PMID: 30029499 PMCID: PMC6070989 DOI: 10.3390/toxins10070300] [Citation(s) in RCA: 87] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2018] [Revised: 07/13/2018] [Accepted: 07/17/2018] [Indexed: 12/12/2022] Open
Abstract
In chronic kidney disease (CKD), accumulation of uremic toxins is associated with an increased risk of CKD progression. Some uremic toxins result from nutrient processing by gut microbiota, yielding precursors of uremic toxins or uremic toxins themselves, such as trimethylamine N-Oxide (TMAO), p-cresyl sulphate, indoxyl sulphate and indole-3 acetic acid. Increased intake of some nutrients may modify the gut microbiota, increasing the number of bacteria that process them to yield uremic toxins. Circulating levels of nutrient-derived uremic toxins are associated to increased risk of CKD progression. This offers the opportunity for therapeutic intervention by either modifying the diet, modifying the microbiota, decreasing uremic toxin production by microbiota, increasing toxin excretion or targeting specific uremic toxins. We now review the link between nutrients, microbiota and uremic toxin with CKD progression. Specific focus will be placed on the generation specific uremic toxins with nephrotoxic potential, the decreased availability of bacteria-derived metabolites with nephroprotective potential, such as vitamin K and butyrate and the cellular and molecular mechanisms linking these toxins and protective factors to kidney diseases. This information provides a conceptual framework that allows the development of novel therapeutic approaches.
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Affiliation(s)
| | - Raul Fernandez-Prado
- Nephrology Department, IIS-Fundación Jiménez Díaz-Universidad Autónoma de Madrid, 28040 Madrid, Spain.
| | - Raquel Esteras
- Nephrology Department, IIS-Fundación Jiménez Díaz-Universidad Autónoma de Madrid, 28040 Madrid, Spain.
| | - Maria Vanessa Perez-Gomez
- Nephrology Department, IIS-Fundación Jiménez Díaz-Universidad Autónoma de Madrid, 28040 Madrid, Spain.
| | - Carolina Gracia-Iguacel
- Nephrology Department, IIS-Fundación Jiménez Díaz-Universidad Autónoma de Madrid, 28040 Madrid, Spain.
| | | | - Mehmet Kanbay
- Department of Internal Medicine, Koc University School of Medicine, Istanbul 34450, Turkey.
| | - Alberto Tejedor
- Nefrología, IIS-Gregorio Marañón, Universidad Complutense de Madrid, 28007 Madrid, Spain.
| | - Alberto Lazaro
- Nefrología, IIS-Gregorio Marañón, Universidad Complutense de Madrid, 28007 Madrid, Spain.
| | - Marta Ruiz-Ortega
- Nephrology Department, IIS-Fundación Jiménez Díaz-Universidad Autónoma de Madrid, 28040 Madrid, Spain.
| | - Emilio Gonzalez-Parra
- Nephrology Department, IIS-Fundación Jiménez Díaz-Universidad Autónoma de Madrid, 28040 Madrid, Spain.
| | - Ana B Sanz
- Nephrology Department, IIS-Fundación Jiménez Díaz-Universidad Autónoma de Madrid, 28040 Madrid, Spain.
| | - Alberto Ortiz
- Nephrology Department, IIS-Fundación Jiménez Díaz-Universidad Autónoma de Madrid, 28040 Madrid, Spain.
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Uremic Toxin Clearance and Cardiovascular Toxicities. Toxins (Basel) 2018; 10:toxins10060226. [PMID: 29865226 PMCID: PMC6024759 DOI: 10.3390/toxins10060226] [Citation(s) in RCA: 49] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2018] [Revised: 05/25/2018] [Accepted: 05/31/2018] [Indexed: 12/31/2022] Open
Abstract
Uremic solutes contribute to cardiovascular disease in renal insufficiency. In this review we describe the clearance of selected uremic solutes, which have been associated with cardiovascular disease. These solutes—indoxyl sulfate (IS), p-cresol sulfate (PCS), phenylacetylglutamine (PAG), trimethylamine-n-oxide (TMAO), and kynurenine—exemplify different mechanisms of clearance. IS and PCS are protein-bound solutes efficiently cleared by the native kidney through tubular secretion. PAG and TMAO are not protein-bound but are also cleared by the native kidney through tubular secretion, while kynurenine is not normally cleared by the kidney. Increases in the plasma levels of the normally secreted solutes IS, PCS, TMAO, and PAG in chronic kidney disease (CKD) are attributable to a reduction in their renal clearances. Levels of each of these potential toxins are even higher in patients on dialysis than in those with advanced chronic kidney disease, which can be accounted for in part by a low ratio of dialytic to native kidney clearance. The rise in plasma kynurenine in CKD and dialysis patients, by contrast, remains to be explained. Our ability to detect lower levels of the potential uremic cardiovascular toxins with renal replacement therapy may be limited by the intermittency of treatment, by increases in solute production, and by the presence of non-renal clearance. Reduction in the levels of uremic cardiovascular toxins may in the future be achieved more effectively by inhibiting their production.
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Abstract
Uremic solutes contribute to cardiovascular disease in renal insufficiency. In this review we describe the clearance of selected uremic solutes, which have been associated with cardiovascular disease. These solutes-indoxyl sulfate (IS), p-cresol sulfate (PCS), phenylacetylglutamine (PAG), trimethylamine-n-oxide (TMAO), and kynurenine-exemplify different mechanisms of clearance. IS and PCS are protein-bound solutes efficiently cleared by the native kidney through tubular secretion. PAG and TMAO are not protein-bound but are also cleared by the native kidney through tubular secretion, while kynurenine is not normally cleared by the kidney. Increases in the plasma levels of the normally secreted solutes IS, PCS, TMAO, and PAG in chronic kidney disease (CKD) are attributable to a reduction in their renal clearances. Levels of each of these potential toxins are even higher in patients on dialysis than in those with advanced chronic kidney disease, which can be accounted for in part by a low ratio of dialytic to native kidney clearance. The rise in plasma kynurenine in CKD and dialysis patients, by contrast, remains to be explained. Our ability to detect lower levels of the potential uremic cardiovascular toxins with renal replacement therapy may be limited by the intermittency of treatment, by increases in solute production, and by the presence of non-renal clearance. Reduction in the levels of uremic cardiovascular toxins may in the future be achieved more effectively by inhibiting their production.
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Affiliation(s)
- Robert D Mair
- The Departments of Medicine, VA Palo Alto Healthcare System, 111R, 3801 Miranda Ave., Palo Alto, CA 94304, USA.
- Division of Nephrology, Stanford University, 777 Welch Road, Suite DE, Palo Alto, CA 94304, USA.
| | - Tammy L Sirich
- The Departments of Medicine, VA Palo Alto Healthcare System, 111R, 3801 Miranda Ave., Palo Alto, CA 94304, USA.
- Division of Nephrology, Stanford University, 777 Welch Road, Suite DE, Palo Alto, CA 94304, USA.
| | - Timothy W Meyer
- The Departments of Medicine, VA Palo Alto Healthcare System, 111R, 3801 Miranda Ave., Palo Alto, CA 94304, USA.
- Division of Nephrology, Stanford University, 777 Welch Road, Suite DE, Palo Alto, CA 94304, USA.
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Yi D, Monteiro EB, Chambert S, Soula HA, Daleprane JB, Soulage CO. Determination of the binding properties of p-cresyl glucuronide to human serum albumin. Biochimie 2018; 150:1-7. [PMID: 29705133 DOI: 10.1016/j.biochi.2018.04.019] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2017] [Accepted: 04/23/2018] [Indexed: 12/20/2022]
Abstract
p-Cresyl glucuronide (p-CG) is a by-product of tyrosine metabolism that accumulates in patients with end-stage renal disease. p-CG binding to human serum albumin in physiological conditions (37 °C, pH 7.40) was studied by ultrafiltration (MWCO 10 kDa) and data were analyzed assuming one binding site. The estimated value of the association constant was 2.77 × 103 M-1 and a maximal stoichiometry of 3.80 mol per mole. At a concentration relevant for end-stage renal patients, p-CG was 23% bound to albumin. Competition experiments, using fluorescent probes, demonstrated that p-CG did not bind to Sudlow's site I or site II. The p-CG did not interfere with the binding of p-cresyl-sulfate or indoxyl sulfate to serum albumin.
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Affiliation(s)
- Dan Yi
- Univ. Lyon, CarMeN, INSERM U1060, INRA U1397, INSA de Lyon, Université Claude Bernard Lyon 1, F-69621 Villeurbanne, France
| | - Elisa Bernardes Monteiro
- Univ. Lyon, CarMeN, INSERM U1060, INRA U1397, INSA de Lyon, Université Claude Bernard Lyon 1, F-69621 Villeurbanne, France; Laboratory for Studies of Interactions Between Nutrition and Genetics, LEING, Department of Basic and Experimental Nutrition, Rio de Janeiro State University, Rio de Janeiro, Brazil
| | - Stéphane Chambert
- INSA Lyon, ICBMS, Laboratoire de Chimie Organique et Bioorganique, Bât J. Verne, 20 av A. Einstein, 69621 Villeurbanne Cedex, France
| | - Hédi A Soula
- Sorbonne Universités, Univ. Pierre et Marie Curie - Paris 6, 75006 Paris, France
| | - Julio B Daleprane
- Laboratory for Studies of Interactions Between Nutrition and Genetics, LEING, Department of Basic and Experimental Nutrition, Rio de Janeiro State University, Rio de Janeiro, Brazil
| | - Christophe O Soulage
- Univ. Lyon, CarMeN, INSERM U1060, INRA U1397, INSA de Lyon, Université Claude Bernard Lyon 1, F-69621 Villeurbanne, France.
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Bogiatzi C, Gloor G, Allen-Vercoe E, Reid G, Wong RG, Urquhart BL, Dinculescu V, Ruetz KN, Velenosi TJ, Pignanelli M, Spence JD. Metabolic products of the intestinal microbiome and extremes of atherosclerosis. Atherosclerosis 2018; 273:91-97. [PMID: 29702430 DOI: 10.1016/j.atherosclerosis.2018.04.015] [Citation(s) in RCA: 97] [Impact Index Per Article: 16.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/29/2017] [Revised: 04/03/2018] [Accepted: 04/11/2018] [Indexed: 11/30/2022]
Abstract
BACKGROUND AND AIMS There is increasing awareness that the intestinal microbiome plays an important role in human health. We investigated its role in the burden of carotid atherosclerosis, measured by ultrasound as total plaque area. METHODS Multiple regression with traditional risk factors was used to identify three phenotypes among 316/3056 patients attending vascular prevention clinics. Residual score (RES; i.e. the distance off the regression line, similar to standard deviation) was used to identify the 5% of patients with much less plaque than predicted by their risk factors (Protected, RES <-2), the 90% with about as much plaque as predicted (Explained, RES -2 to 2), and the 5% with much more plaque than predicted (Unexplained RES >2). Metabolic products of the intestinal microbiome that accumulate in renal failure - gut-derived uremic toxins (GDUT) - were assayed in plasma by ultra-performance liquid chromatography coupled to quadrupole time-of-flight mass spectrometry. RESULTS Plasma levels of trimethylamine n-oxide (TMAO), p-cresyl sulfate, p-cresyl glucuronide, and phenylacetylglutamine were significantly lower among patients with the Protected phenotype, and higher in those with the Unexplained phenotype, despite no significant differences in renal function or in dietary intake of nutrient precursors of GDUT. In linear multiple regression with a broad panel of risk factors, TMAO (p = 0.011) and p-cresyl sulfate (p = 0.011) were significant independent predictors of carotid plaque burden. CONCLUSIONS The intestinal microbiome appears to play an important role in atherosclerosis. These findings raise the possibility of novel approaches to treatment of atherosclerosis such as fecal transplantation and probiotics.
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Affiliation(s)
- Chrysi Bogiatzi
- Stroke Prevention & Atherosclerosis Research Centre, Robarts Research Institute, Western University, London, Canada; Dept. of Neurology, McMaster University, Hamilton, Canada
| | - Gregory Gloor
- Dept. Biochemistry, Schulich School of Medicine and Dentistry, Western University, London, Canada
| | - Emma Allen-Vercoe
- Dept. Molecular and Cell Biology, University of Guelph, Guelph, Canada
| | - Gregor Reid
- Depts. of Urology and Microbiology, Schulich School of Medicine and Dentistry, Western University, London, Canada
| | - Ruth G Wong
- Dept. Biochemistry, Schulich School of Medicine and Dentistry, Western University, London, Canada
| | - Bradley L Urquhart
- Dept. Physiology & Pharmacology, Schulich School of Medicine and Dentistry Western University, London, Canada
| | | | - Kelsey N Ruetz
- Dept. Physiology & Pharmacology, Schulich School of Medicine and Dentistry Western University, London, Canada
| | - Thomas J Velenosi
- Dept. Physiology & Pharmacology, Schulich School of Medicine and Dentistry Western University, London, Canada
| | - Michael Pignanelli
- Schulich School of Medicine and Dentistry M.D. Candidate (CIHR Summer Research Training Program), Canada
| | - J David Spence
- Stroke Prevention & Atherosclerosis Research Centre, Robarts Research Institute, Western University, London, Canada; Divisions of Neurology and Clinical Pharmacology, Western University, London, Canada.
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49
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Bosch-Panadero E, Mas S, Civantos E, Abaigar P, Camarero V, Ruiz-Priego A, Ortiz A, Egido J, González-Parra E. Bisphenol A is an exogenous toxin that promotes mitochondrial injury and death in tubular cells. ENVIRONMENTAL TOXICOLOGY 2018; 33:325-332. [PMID: 29214717 DOI: 10.1002/tox.22519] [Citation(s) in RCA: 48] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/08/2017] [Revised: 11/08/2017] [Accepted: 11/17/2017] [Indexed: 06/07/2023]
Abstract
BACKGROUND Uremic toxins that accumulate in chronic kidney disease (CKD) contribute to CKD complications, such as CKD progression. Bisphenol A (BPA) is a ubiquitous environmental toxin, structurally related with p-cresol, that accumulates in CKD. Our aim was to characterize the nephrotoxic potential of BPA. Specifically, we addressed BPA toxicity over energy-demanding proximal tubular cells. METHODS Cell death and oxidative stress were evaluated by flow cytometry and confocal microscopy in HK-2 human proximal tubular epithelial cells. Functional assays tested ATP, intracellular Ca2+ , mitochondrial function (tetramethylrhodamine methyl [TMRM]), oxygen consumption, Nrf2-binding, MitoSOX, and NADPH oxidase activity. Gene expression was assessed by qRT-PCR. RESULTS Following acute exposure (24 hours), proximal tubular cell viability was decreased by BPA concentrations ≥50 μM while a seven-day exposure resulted in a progressive loss of cell viability at a nanomolar range. Within 24 hours, BPA promoted mitochondrial dysfunction leading to energy depletion and increased mitochondrial and cytoplasmic oxidative stress and apoptosis in a concentration-dependent manner. An antioxidant response was observed manifested by nuclear Nrf2 translocation and increased expression of the Nrf2 target genes Heme oxygenase 1 (HO-1) and NAD(P)H dehydrogenase [quinone] 1 (NQO-1). CONCLUSIONS This study demonstrates for the first time that BPA causes mitochondrial injury, oxidative stress and apoptotic death in tubular cells. These results characterize BPA as an exogenous toxin that, similar to uremic toxins, may contribute to CKD progression.
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Affiliation(s)
- Enrique Bosch-Panadero
- Renal, Vascular and Diabetes Research Laboratory, Av Reyes Catolicos 2, Madrid, E-28040, Spain
| | - Sebastian Mas
- Renal, Vascular and Diabetes Research Laboratory, Av Reyes Catolicos 2, Madrid, E-28040, Spain
- Spanish Biomedical Research Centre in Diabetes and Associated Metabolic Disorders (CIBERDEM), Spain
| | - Esther Civantos
- Spanish Biomedical Research Centre in Diabetes and Associated Metabolic Disorders (CIBERDEM), Spain
| | - Pedro Abaigar
- Division of Nephrology, Hospital Universitario de Burgos, Burgos, Spain
| | - Vanesa Camarero
- Division of Nephrology, Hospital Universitario de Burgos, Burgos, Spain
| | - Alberto Ruiz-Priego
- Renal, Vascular and Diabetes Research Laboratory, Av Reyes Catolicos 2, Madrid, E-28040, Spain
| | - Alberto Ortiz
- Renal, Vascular and Diabetes Research Laboratory, Av Reyes Catolicos 2, Madrid, E-28040, Spain
- Division of Nephrology and Hypertension, IIS-Fundación Jimenez Diaz UAM, Madrid, Spain
- Department of Medicine, UAM, Madrid, Spain
- Kidney Research Network (REDINREN), Madrid, Spain
| | - Jesus Egido
- Renal, Vascular and Diabetes Research Laboratory, Av Reyes Catolicos 2, Madrid, E-28040, Spain
- Spanish Biomedical Research Centre in Diabetes and Associated Metabolic Disorders (CIBERDEM), Spain
- Division of Nephrology and Hypertension, IIS-Fundación Jimenez Diaz UAM, Madrid, Spain
- Department of Medicine, UAM, Madrid, Spain
| | - Emilio González-Parra
- Renal, Vascular and Diabetes Research Laboratory, Av Reyes Catolicos 2, Madrid, E-28040, Spain
- Division of Nephrology and Hypertension, IIS-Fundación Jimenez Diaz UAM, Madrid, Spain
- Department of Medicine, UAM, Madrid, Spain
- Kidney Research Network (REDINREN), Madrid, Spain
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50
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Sell DR, Nemet I, Liang Z, Monnier VM. Evidence of glucuronidation of the glycation product LW-1: tentative structure and implications for the long-term complications of diabetes. Glycoconj J 2018; 35:177-190. [PMID: 29305779 DOI: 10.1007/s10719-017-9810-7] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2017] [Accepted: 12/01/2017] [Indexed: 01/06/2023]
Abstract
LW-1 is a collagen-linked blue fluorophore whose skin levels increase with age, diabetes and end-stage renal disease (ESRD), and correlate with the long-term progression of microvascular disease and indices of subclinical cardiovascular disease in type 1 diabetes. The chemical structure of LW-1 is still elusive, but earlier NMR analyses showed it has a lysine residue in an aromatic ring coupled to a sugar molecule reminiscent of advanced glycation end-products (AGEs). We hypothesized and demonstrate here that the unknown sugar is a N-linked glucuronic acid. LW-1 was extracted and highly purified from ~99 g insoluble skin collagen obtained at autopsy from patients with diabetes/ESRD using multiple rounds of proteolytic digestion and purification by liquid chromatography (LC). Advanced NMR techniques (1H-NMR, 13C-NMR, 1H-13C HSQC, 1H-1H TOCSY, 1H-13C HMBC) together with LC-mass spectrometry (MS) revealed a loss of 176 amu (atomic mass unit) unequivocally point to the presence of a glucuronic acid moiety in LW-1. To confirm this data, LW-1 was incubated with β-glycosidases (glucosidase, galactosidase, glucuronidase) and products were analyzed by LC-MS. Only glucuronidase could cleave the sugar from the parent molecule. These results establish LW-1 as a glucuronide, now named glucuronidine, and for the first time raise the possible existence of a "glucuronidation pathway of diabetic complications". Future research is needed to rigorously probe this concept and elucidate the molecular origin and biological source of a circulating glucuronidine aglycone.
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Affiliation(s)
- David R Sell
- Department of Pathology, Case Western Reserve University, Wolstein Research Bldg. 5-301, 2103 Cornell Road, Cleveland, OH, 44106, USA.
| | - Ina Nemet
- Department of Cellular and Molecular Medicine, Lerner Research Institute, Cleveland Clinic Foundation, Cleveland, OH, 44195, USA
| | - Zhili Liang
- School of Food Science and Engineering, South China University of Technology, Guangzhou, 510640, China
| | - Vincent M Monnier
- Department of Pathology, Case Western Reserve University, Wolstein Research Bldg. 5-301, 2103 Cornell Road, Cleveland, OH, 44106, USA. .,Department of Biochemistry, Case Western Reserve University, Cleveland, OH, 44106, USA.
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