4-cresol-sulfate and 4-cresol

In the last decade, uremic toxicity as a potential cause for the excess of cardiovascular disease and mortality observed in chronic kidney disease gained more and more interest. This review focuses on uremic toxins with known cardiovascular effects and their removal. For protein-bound solutes, for example, indoxylsulfate and the conjugates of p-cresol, and for small water-soluble solutes, for example, guanidines, such as ADMA and SDMA, there is a growing evidence for a role in cardiovascular toxicity in vitro (e.g., affecting leukocyte, endothelial, vascular smooth muscle cell function) and/or in vivo. Several middle molecules (e.g., beta-2-microglobulin, interleukin-6, TNF-alpha and FGF-23) were shown to be predictors for cardiovascular disease and/or mortality. Most of these solutes, however, are difficult to remove during dialysis, which is traditionally assessed by studying the removal of urea, which can be considered as a relatively inert uremic retention solute. However, even the effective removal of other small water-soluble toxins than urea can be hampered by their larger distribution volumes. Middle molecules (beta-2-microglobulin as prototype, but not necessarily representative for others) are cleared more efficiently when the pore size of the dialyzer membrane increases, convection is applied and dialysis time is prolonged. Only adding convection to diffusion improves the removal of protein-bound toxins. Therefore, alternative removal strategies, such as intestinal adsorption, drugs interfering with toxic biochemical pathways or decreasing toxin concentration, and extracorporeal plasma adsorption, as well as kinetic behavior during dialysis need further investigation. Even more importantly, randomized clinical studies are required to demonstrate a survival advantage through these strategies.

Topics: beta 2-Microglobulin; Biomarkers; Cardiovascular Diseases; Cresols; Dialysis Solutions; Fibroblast Growth Factor-23; Glucuronides; Guanidines; Humans; Indican; Peptides; Protein Binding; Renal Dialysis; Sulfuric Acid Esters; Urea; Uremia

We provide a demonstration in humans of the principle of pharmacometabonomics by showing a clear connection between an individual's metabolic phenotype, in the form of a predose urinary metabolite profile, and the metabolic fate of a standard dose of the widely used analgesic acetaminophen. Predose and postdose urinary metabolite profiles were determined by (1)H NMR spectroscopy. The predose spectra were statistically analyzed in relation to drug metabolite excretion to detect predose biomarkers of drug fate and a human-gut microbiome cometabolite predictor was identified. Thus, we found that individuals having high predose urinary levels of p-cresol sulfate had low postdose urinary ratios of acetaminophen sulfate to acetaminophen glucuronide. We conclude that, in individuals with high bacterially mediated p-cresol generation, competitive O-sulfonation of p-cresol reduces the effective systemic capacity to sulfonate acetaminophen. Given that acetaminophen is such a widely used and seemingly well-understood drug, this finding provides a clear demonstration of the immense potential and power of the pharmacometabonomic approach. However, we expect many other sulfonation reactions to be similarly affected by competition with p-cresol and our finding also has important implications for certain diseases as well as for the variable responses induced by many different drugs and xenobiotics. We propose that assessing the effects of microbiome activity should be an integral part of pharmaceutical development and of personalized health care. Furthermore, we envisage that gut bacterial populations might be deliberately manipulated to improve drug efficacy and to reduce adverse drug reactions.

Topics: Acetaminophen; Administration, Oral; Adolescent; Adult; Analgesics, Non-Narcotic; Bacteria; Cresols; Gastrointestinal Tract; Host-Pathogen Interactions; Humans; Magnetic Resonance Spectroscopy; Male; Middle Aged; Sulfates; Sulfuric Acid Esters; Young Adult

Removal of protein-bound uremic retention solutes, including p-cresol, by peritoneal dialysis and hemodialysis (HD) is limited. p-Cresol, mainly circulating as sulfate conjugate (p-cresyl sulfate [PCS]), is independently associated with mortality. Fractionated plasma separation and adsorption (FPSA) is a nonbiologic detoxification system for the treatment of liver failure. The FPSA clearance of uremic retention solutes is unknown. We studied PCS clearance by FPSA, using the Prometheus system. The neutral resin adsorbent and the anion exchange adsorbent bind PCS in vitro (reduction ratios [RRs] 37 and 70%). Ex vivo, the adsorbent mass removal (MR) (median 47.5 mg) contributes more than half to total MR (median 89.6 mg). In vivo, PCS RR during FPSA (50%) exceeded the RR during high flux HD (30%). We halted the study after four inclusions due to repeated thrombosis of the arterio-venous conduit. In conclusion, FPSA is a promising technique to improve clearance of protein-bound uremic retention solutes.

Topics: Adsorption; Anion Exchange Resins; Arteriovenous Shunt, Surgical; Cresols; Cross-Over Studies; Humans; Ion Exchange; Plasmapheresis; Renal Dialysis; Renal Insufficiency, Chronic; Sulfuric Acid Esters; Thrombosis; Treatment Outcome; Uremia

Protein-bound uremic toxins, mainly indoxyl sulfate (3-INDS), p-cresol sulfate (pCS), and indole-3-acetic acid (3-IAA) but also phenol (Pol) and p-cresol (pC), are progressively accumulated during chronic kidney disease (CKD). Their accurate measurement in biomatrices is demanded for timely diagnosis and adoption of appropriate therapeutic measures. Multianalyte methods allowing the establishment of a uremic metabolite profile are still missing. Hence, the aim of this work was to develop a rapid and sensitive method based on high-performance liquid chromatography with fluorescence detection for the simultaneous quantification of Pol, 3-IAA, pC, 3-INDS, and pCS in human plasma. Separation was attained in 12 min, using a monolithic C18 column and isocratic elution with acetonitrile and phosphate buffer containing an ion-pairing reagent, at a flow rate of 2 mL min

Topics: Chromatography, High Pressure Liquid; Cresols; Humans; Indican; Phenol; Renal Insufficiency, Chronic; Toxins, Biological; Uremic Toxins

Mycophenolic acid (MPA) is commonly prescribed for preventing graft rejection after kidney transplantation. The primary metabolic pathways of MPA are hepatic glucuronidation through UDP-glucuronosyltransferase (UGT) enzymes in the formation of MPA-glucuronide (MPAG, major pathway) and MPA-acyl glucuronide (AcMPAG). p-Cresol, a potent uremic toxin known to accumulate in patients with renal dysfunction, can potentially interact with MPA via the inhibition of glucuronidation. We hypothesized that the interaction between MPA and p-cresol is clinically relevant and that the estimated exposure changes in the clinic are of toxicological significance. Using in vitro approaches (ie, human liver microsomes and recombinant enzymes), the potency and mechanisms of inhibition by p-cresol towards MPA glucuronidation were characterized. Inter-individual variabilities, effects of clinical co-variates, in vitro-in vivo prediction of likely changes in MPA exposure, and comparison to other toxins were determined for clinical relevance. p-Cresol inhibited MPAG formation in a potent and competitive manner (Ki=5.2 µM in pooled human liver microsomes) and the interaction was primarily mediated by UGT1A9. This interaction was estimated to increase plasma MPA exposure in patients by approximately 1.8-fold, which may result in MPA toxicity. The mechanism of inhibition for AcMPAG formation was noncompetitive (Ki=127.5 µM) and less likely to be clinically significant. p-Cresol was the most potent inhibitor of MPA-glucuronidation compared with other commonly studied uremic toxins (eg, indole-3-acetic acid, indoxyl sulfate, hippuric acid, kynurenic acid, and 3-carboxy-4-methyl-5-propyl-2-furanpropionic acid) and its metabolites (ie, p-cresol sulfate and p-cresol glucuronide). Our findings indicate that the interaction between p-cresol and MPA is of toxicological significance and warrants clinical investigation.

Topics: Cresols; Glucuronides; Glucuronosyltransferase; Microsomes, Liver; Mycophenolic Acid; Sulfuric Acid Esters; UDP-Glucuronosyltransferase 1A9

The industrial manufacturing process of lactose-free milk products depends on the application of commercial β-galactosidase (lactase) preparations. These preparations are often obtained from Kluyveromyces lactis. There is a gene present in the genome of K. lactis which should encode for an enzyme called arylsulfatase (EC 3.1.6.1). Therefore, this enzyme could also be present in β-galactosidase preparations. The arylsulfatase is suspected of being responsible for an unpleasant "cowshed-like" off-flavor resulting from the release of p-cresol from milk endogenous alkylphenol sulfuric esters. So far, no gene/functionality relationship is described. In addition, no study is available which has shown that arylsulfatase from K. lactis is truly responsible for the flavor generation. In this study, we cloned the putative arylsulfatase gene from K. lactis GG799 into the commercially available vector pKLAC2. The cloning strategy chosen resulted in a homologous, secretory expression of the arylsulfatase. We showed that the heretofore putative arylsulfatase has the desired activity with the synthetic substrate p-nitrophenyl sulfate and with the natural substrate p-cresol sulfate. The enzyme was biochemically characterized and showed an optimum temperature of 45-50 °C and an optimum pH of 9-10. Additionally, the arylsulfatase was activated by Ca(2+) ions and was inactivated by Zn(2+) ions. Moreover, the arylsulfatase was inhibited by p-cresol and sulfate ions. Finally, the enzyme was added to ultra-heat treated (UHT) milk and a sensory triangle test verified that the arylsulfatase from K. lactis can cause an unpleasant "cowshed-like" off-flavor.

Topics: Animals; Arylsulfatases; beta-Galactosidase; Cloning, Molecular; Cresols; Hydrogen-Ion Concentration; Hydrolysis; Industrial Microbiology; Kluyveromyces; Lactose; Milk; Nitrobenzenes; Sulfuric Acid Esters; Temperature

p-cresol (PC) and p-cresyl sulfate (PCS) are responsible for many of the uremia clinical consequences, such as atherosclerosis in Chronic Kidney Disease (CKD) patients.. We investigate the in vitro impact of PC and PCS on monocyte chemoattractant protein-1 (MCP-1) expression via NF-kappa B (NF-κB) p65 in VSMC.. PCS was synthesized by PC sulfatation. VSMC were extracted by enzymatic digestion of umbilical cord vein and characterized by immunofluorescence against α-actin antibody. The cells were treated with PC and PCS at their normal (n), uremic (u) and maximum uremic concentrations (m). Cell viability was assessed by MTT. MCP-1 expression was investigated by ELISA in cells supernatants after toxins treatment with or without the NF-κB p65 inhibitor.. There was no significant difference in cell viability after toxins treatment for all concentrations tested. There was a significant increase in MCP-1 expression in cells treated with PCu and PCm (p < 0.001) and PCSn, PCSu and PCSm (p < 0.001), compared with the control. When VSMC were treated with the NF-κB p65 inhibitor plus PCu and PCm, there was a significant decrease in MCP-1 production (p < 0.005). This effect was not observed with PCS.. VSMC are involved in atherosclerosis lesion formation and production of MCP-1, which contributes to the inflammatory response initiation. Our results suggest that PC mediates MCP-1 production in VSMC, probably through NF-κB p65 pathway, although we hypothesize that PCS acts through a different subunit pathway since NF-κB p65 inhibitor was not able to inhibit MCP-1 production.

Topics: Cells, Cultured; Chemokine CCL2; Cresols; Humans; Muscle, Smooth, Vascular; Sulfuric Acid Esters; Transcription Factor RelA

Intestinal microbiome constitutes a symbiotic ecosystem that is essential for health, and changes in its composition/function cause various illnesses. Biochemical milieu shapes the structure and function of the microbiome. Recently, we found marked differences in the abundance of numerous bacterial taxa between ESRD and healthy individuals. Influx of urea and uric acid and dietary restriction of fruits and vegetables to prevent hyperkalemia alter ESRD patients' intestinal milieu. We hypothesized that relative abundances of bacteria possessing urease, uricase, and p-cresol- and indole-producing enzymes is increased, while abundance of bacteria containing enzymes converting dietary fiber to short-chain fatty acids (SCFA) is reduced in ESRD.. Reference sets of bacteria containing genes of interest were compiled to family, and sets of intestinal bacterial families showing differential abundances between 12 healthy and 24 ESRD individuals enrolled in our original study were compiled. Overlap between sets was assessed using hypergeometric distribution tests.. Among 19 microbial families that were dominant in ESRD patients, 12 possessed urease, 5 possessed uricase, and 4 possessed indole and p-cresol-forming enzymes. Among 4 microbial families that were diminished in ESRD patients, 2 possessed butyrate-forming enzymes. Probabilities of these overlapping distributions were <0.05.. ESRD patients exhibited significant expansion of bacterial families possessing urease, uricase, and indole and p-cresol forming enzymes, and contraction of families possessing butyrate-forming enzymes. Given the deleterious effects of indoxyl sulfate, p-cresol sulfate, and urea-derived ammonia, and beneficial actions of SCFA, these changes in intestinal microbial metabolism contribute to uremic toxicity and inflammation.

Topics: Adult; Aged; Ammonia; Cresols; Diet; Fatty Acids, Volatile; Female; Humans; Indican; Indoles; Inflammation; Intestines; Kidney Failure, Chronic; Male; Microbiota; Middle Aged; Sulfuric Acid Esters; Urate Oxidase; Urea; Urease

The aromatic compound p-cresol (4-methylphenol) has been found elevated in the urines of Italian autistic children up to 8 years of age. The present study aims at replicating these initial findings in an ethnically distinct sample and at extending them by measuring also the three components of urinary p-cresol, namely p-cresylsulfate, p-cresylglucuronate and free p-cresol. Total urinary p-cresol, p-cresylsulfate and p-cresylglucuronate were significantly elevated in 33 French autism spectrum disorder (ASD) cases compared with 33 sex- and age-matched controls (p < 0.05). This increase was limited to ASD children aged ≤8 years (p < 0.01), and not older (p = 0.17). Urinary levels of p-cresol and p-cresylsulfate were associated with stereotypic, compulsive/repetitive behaviors (p < 0.05), although not with overall autism severity. These results confirm the elevation of urinary p-cresol in a sizable set of small autistic children and spur interest into biomarker roles for p-cresol and p-cresylsulfate in autism.

Topics: Adolescent; Case-Control Studies; Child; Child Development Disorders, Pervasive; Child, Preschool; Cresols; Female; France; Glucuronates; Humans; Male; Sulfuric Acid Esters

The mechanisms underlying the insulin resistance that frequently accompanies CKD are poorly understood, but the retention of renally excreted compounds may play a role. One such compound is p-cresyl sulfate (PCS), a protein-bound uremic toxin that originates from tyrosine metabolism by intestinal microbes. Here, we sought to determine whether PCS contributes to CKD-associated insulin resistance. Administering PCS to mice with normal kidney function for 4 weeks triggered insulin resistance, loss of fat mass, and ectopic redistribution of lipid in muscle and liver, mimicking features associated with CKD. Mice treated with PCS exhibited altered insulin signaling in skeletal muscle through ERK1/2 activation. In addition, exposing C2C12 myotubes to concentrations of PCS observed in CKD caused insulin resistance through direct activation of ERK1/2. Subtotal nephrectomy led to insulin resistance and dyslipidemia in mice, and treatment with the prebiotic arabino-xylo-oligosaccharide, which reduced serum PCS by decreasing intestinal production of p-cresol, prevented these metabolic derangements. Taken together, these data suggest that PCS contributes to insulin resistance and that targeting PCS may be a therapeutic strategy in CKD.

Topics: Adipocytes; Adipose Tissue, White; Animals; Cresols; Disease Models, Animal; Extracellular Signal-Regulated MAP Kinases; Glucose; Hypercholesterolemia; Hyperglycemia; Insulin; Insulin Resistance; Lipid Metabolism; Mice; Mice, Inbred C57BL; Muscle, Skeletal; Prebiotics; Renal Insufficiency, Chronic; Signal Transduction; Sulfuric Acid Esters; Uremia

Patients afflicted with chronic kidney disease (CKD) typically suffer from cardiovascular disease (CVD) which is a leading cause of patient mortality. It has been demonstrated that two distinct physiological events contribute to this disease state. These include the abundance of abnormally high levels of protein-bound uraemic toxins as well as functionally aberrant endothelial progenitor cells (EPCs). Specifically, it has been demonstrated that the uraemic toxin p-cresol (pC; 4-methylphenol) inhibits EPC proliferation and tube formation in previous in vitro studies. More recently, however, it has been demonstrated that circulating pC is actually conjugated and that p-cresylsulphate (pCS) is its main metabolite. Therefore, within the context of this study, we examined the in vitro effects of pC and pCS treatment on cultured human EPCs.. Late-outgrowth EPCs were treated with physiological concentrations of pC or pCS (10, 40, 80, and 160 or 10, 40, 80, 160 and 320 µg/mL for up to 72 h, respectively) in the presence of 4% human serum albumin (HSA). Cell proliferation was determined using WST-1 assay, while migration and tube formation assays were used to evaluate EPC function in vitro. Cell cycle analyses were also performed to determine the effects of pC and pCS on cell cycle status.. With regard to EPC proliferation, data demonstrate that pC in the presence or absence of HSA had an IC50 of 80.1 and 100.8 µg/mL 72 h post-treatment, respectively, while pCS-treated groups did not impair EPC proliferation. Similarly, pC-treated groups showed limited vessel formation and migration compared with controls and no detrimental effects were seen with pCS treatment. Lastly, pC treatment of EPCs caused cells to accumulate in the G2/M phase of the cell cycle with accompanied down-regulation of cyclin B1 and phosphorylated CDK1. pCS had no effect on cell cycle parameters.. Our data demonstrate that pC and pCS have different effects on EPC function. Since there is a dearth of data that have focused on the toxicity of pCS, further research should be performed to determine the exact biological toxicity of pCS on the cardiovascular system.

Topics: Cells, Cultured; Cresols; Endothelial Cells; Humans; Stem Cells; Sulfuric Acid Esters

p-Cresylsulfate, a metabolite of p-cresol, is reported as prototypic protein-bound uremic toxin, inefficiently removed by haemodialysis. The binding between p-cresylsulfate or p-cresol and human serum albumin was studied using microcalorimetry. The results confirm that the two molecules are protein-bound. However, the affinity of p-cresylsulfate and p-cresol toward human serum albumin is moderate at 25 degrees C and becomes relatively weak at physiological temperature, 37 degrees C. The binding principally involves van der Waals type interactions, and the binding sites of the two molecules are the same or very close. The low fraction of bound toxin (13-20%) appears to be insufficient to link strong binding to poor removal of this toxin by hemodialysis.

Topics: Binding Sites; Calorimetry; Cresols; Humans; Protein Binding; Renal Dialysis; Serum Albumin; Sulfuric Acid Esters; Temperature; Thermodynamics

Topics: Acetaminophen; Administration, Oral; Analgesics, Non-Narcotic; Bacteria; Cresols; Gastrointestinal Tract; Host-Pathogen Interactions; Humans; Sulfates; Sulfuric Acid Esters

Chronic renal insufficiency is associated with the retention of solutes normally excreted by healthy kidneys. P-cresol, a prototype protein-bound uraemic retention solute, has been shown to exert toxic effects in vitro. Recently, however, it has been demonstrated that p-cresol in the human body is conjugated, with p-cresylsulphate as the main metabolite.. The present study evaluates the effect of p-cresylsulphate on the respiratory burst activity of leucocytes.. P-cresylsulphate significantly increased the percentage of leucocytes displaying oxidative burst activity at baseline. Oxidative burst activity of stimulated leucocytes was however not affected. In contrast, p-cresol had no effect on the leucocytes at baseline, but inhibited leucocytes burst activity after stimulation.. The present study demonstrates, for the first time, that p-cresylsulphate, the main in vivo metabolite of p-cresol, has a pro-inflammatory effect on unstimulated leucocytes. This effect could contribute to the propensity to vascular disease in the uraemic population.

Topics: Biomarkers; Cresols; Endotoxins; Escherichia coli; Free Radicals; Humans; Leukocytes; Respiratory Burst; Sulfuric Acid Esters; Uremia

The capacity of sorbent systems to increase solute clearances above the levels that are provided by hemodialysis has not been well defined. This study assessed the extent to which solute clearances can be increased by addition of a sorbent to the dialysate. Attention was focused on the clearance of protein-bound solutes, which are cleared poorly by conventional hemodialysis. A reservoir that contained test solutes and artificial plasma was dialyzed first with the plasma flow set at 46 +/- 3 ml/min and the dialysate flow (Q(d)) set at 42 +/- 3 ml/min using a hollow fiber kidney with mass transfer area coefficients greater than Q(d) for each of the solutes. Under these conditions, the clearance of urea (Cl(urea)) was 34 +/- 1 ml/min, whereas the clearances of the protein-bound solutes indican (Cl(ind)), p-cresol sulfate (Cl(pcs)), and p-cresol (Cl(pc)) averaged only 5 +/- 1, 4 +/- 1, and 14 +/- 1 ml/min, respectively The effect of addition of activated charcoal to the dialysate then was compared with the effect of increasing Q(d) without addition of any sorbent. Addition of charcoal increased Cl(ind), Cl(pcs), and Cl(pc) to 12 +/- 1, 9 +/- 2, and 35 +/- 4 ml/min without changing Cl(urea). Increasing Q(d) without the addition of sorbent had a similar effect on the clearance of the protein-bound solutes. Mathematical modeling predicted these changes and showed that the maximal effect of addition of a sorbent to the dialysate is equivalent to that of an unlimited increase in Q(d). These results suggest that as an adjunct to conventional hemodialysis, addition of sorbents to the dialysate could increase the clearance of protein-bound solutes without greatly altering the clearance of unbound solutes.

Topics: Charcoal; Cresols; Dialysis Solutions; Humans; Indican; Models, Biological; Protein Binding; Proteins; Renal Dialysis; Sulfuric Acid Esters; Urea

Topics: Adult; Aged; Cresols; Gas Chromatography-Mass Spectrometry; Glucuronates; Glucuronides; Heating; Humans; Hydrogen-Ion Concentration; Nitrobenzenes; Reference Values; Renal Dialysis; Renal Insufficiency; Sulfuric Acid Esters; Uremia

Multiple sclerosis (MS) is clinically heterogeneous and has an uncertain natural history. A high priority for more effective treatment of MS is an objective and feasible laboratory test for predicting the disease's course and response to treatments. Urinary myelin basic protein (MBP)-like material (MBPLM), so designated because it is immunoreactive as a cryptic epitope in peptide 83-89 of the human MBP molecule of 170 amino acids, is present in normal adults, remains normal in relapsing-remitting, but increases in progressive MS. In the present investigation, MBPLM was purified from urine and characterized. p-Cresol sulfate is the major component of urinary MBPLM. This conclusion is based on the following: (1) MBPLM and p-cresol sulfate both have a mass of 187 on negative scans by electrospray ionization mass spectrometry, the same fragments on tandem mass spectrometry of 80 (SO(-)(3)) and 107 (methylphenol), and similar profiles on multiple reaction monitoring; (2) (1)H and (13)C nuclear magnetic resonance spectroscopy revealed identical spectra for MBPLM and p-cresol sulfate; (3) purified p-cresol sulfate reacted in parallel with MBP peptide 83-89 in the same radioimmunoassay for MBPLM; and (4) p-cresol sulfate has the same behavior on preparative HPLC columns as urinary MBPLM. The unexpected immunochemical degeneracy permitting a cross-reaction between p-cresol sulfate and a peptide of an encephalitogenic myelin protein is postulated to be based on shared conformational features. The mechanisms by which urinary p-cresol sulfate, possibly derived from tyrosine-SO(4), reflects progressive worsening that is disabling in MS are unknown.

Topics: Acetic Acid; Amino Acids; Ammonium Hydroxide; Chromatography, High Pressure Liquid; Cresols; Cross Reactions; Epitopes; Female; Humans; Hydroxides; Isomerism; Magnetic Resonance Spectroscopy; Male; Mass Spectrometry; Middle Aged; Molecular Weight; Multiple Sclerosis; Myelin Basic Protein; Polymers; Radioimmunoassay; Sequence Analysis, Protein; Sulfates; Sulfuric Acid Esters; Tetraethylammonium