4-cresol-sulfate and Renal-Insufficiency

The generation of key uremic nephrovascular toxins, indoxyl sulfate (IS), and p-cresyl sulfate (PCS), is attributed to the dysbiotic gut microbiota in CKD. The aim of our study was to evaluate whether synbiotic (pre- and probiotic) therapy alters the gut microbiota and reduces serum concentrations of microbiome-generated uremic toxins, IS and PCS, in patients with CKD.. Predialysis adult participants with CKD (eGFR=10-30 ml/min per 1.73 m(2)) were recruited between January 5, 2013 and November 12, 2013 to a randomized, double-blind, placebo-controlled, crossover trial of synbiotic therapy over 6 weeks (4-week washout). The primary outcome was serum IS. Secondary outcomes included serum PCS, stool microbiota profile, eGFR, proteinuria-albuminuria, urinary kidney injury molecule-1, serum inflammatory biomarkers (IL-1β, IL-6, IL-10, and TNF-α), serum oxidative stress biomarkers (F2-isoprostanes and glutathione peroxidase), serum LPS, patient-reported health, Gastrointestinal Symptom Score, and dietary intake. A prespecified subgroup analysis explored the effect of antibiotic use on treatment effect.. Of 37 individuals randomized (age =69±10 years old; 57% men; eGFR=24±8 ml/min per 1.73 m(2)), 31 completed the study. Synbiotic therapy did not significantly reduce serum IS (-2 μmol/L; 95% confidence interval [95% CI], -5 to 1 μmol/L) but did significantly reduce serum PCS (-14 μmol/L; 95% CI, -27 to -2 μmol/L). Decreases in both PCS and IS concentrations were more pronounced in patients who did not receive antibiotics during the study (n=21; serum PCS, -25 μmol/L; 95% CI, -38 to -12 μmol/L; serum IS, -5 μmol/L; 95% CI, -8 to -1 μmol/L). Synbiotics also altered the stool microbiome, particularly with enrichment of Bifidobacterium and depletion of Ruminococcaceae. Except for an increase in albuminuria of 38 mg/24 h (P=0.03) in the synbiotic arm, no changes were observed in the other secondary outcomes.. In patients with CKD, synbiotics did not significantly reduce serum IS but did decrease serum PCS and favorably modified the stool microbiome. Large-scale clinical trials are justified.

Topics: Adult; Aged; Aged, 80 and over; Anti-Bacterial Agents; Bacteria; Cresols; Cross-Over Studies; Double-Blind Method; Feces; Female; Gastrointestinal Microbiome; Gastrointestinal Tract; Glomerular Filtration Rate; Humans; Indican; Kidney; Male; Middle Aged; Prebiotics; Probiotics; Queensland; Renal Insufficiency; Severity of Illness Index; Sulfuric Acid Esters; Synbiotics; Time Factors; Treatment Outcome

The protein-bound solutes p-cresol sulfate (PCS) and indoxyl sulfate (IS) accumulate to high plasma levels in renal failure and have been associated with adverse events. The clearance of these bound solutes can be altered independently of the urea clearance by changing the dialysate flow and dialyzer size. This study tested whether a sustained difference in clearance would change the plasma levels of PCS and IS.. Fourteen patients on thrice-weekly nocturnal hemodialysis completed a crossover study of two periods designed to achieve widely different bound solute clearances. We compared the changes in pre-dialysis plasma PCS and IS levels from baseline over the course of the two periods.. The high-clearance period provided much higher PCS and IS clearances than the low-clearance period (PCS: 23 ± 4 mL/min versus 12 ± 3 mL/min, P < 0.001; IS: 30 ± 5 mL/min versus 17 ± 4 mL/min, P < 0.001). Despite the large difference in clearance, the high-clearance period did not have a different effect on PCS levels than the low-clearance period [from baseline, high: +11% (-5, +37) versus low: -8% (-18, +32), (median, 25th, 75th percentile), P = 0.50]. In contrast, the high-clearance period significantly lowered IS levels compared with the low-clearance period [from baseline, high: -4% (-17, +1) versus low: +22% (+14, +31), P < 0.001). The amount of PCS removed in the dialysate was significantly greater at the end of the high-clearance period [269 (206, 312) versus 199 (111, 232) mg per treatment, P < 0.001], while the amount of IS removed was not different [140 (87, 196) versus 116 (89, 170) mg per treatment, P = 0.15].. These findings suggest that an increase in PCS generation prevents plasma levels from falling when the dialytic clearance is increased. Suppression of solute generation may be required to reduce plasma PCS levels in dialysis patients.

Topics: Biomarkers; Cresols; Cross-Over Studies; Dialysis Solutions; Female; Humans; Indican; Male; Middle Aged; Renal Dialysis; Renal Insufficiency; Sulfuric Acid Esters

Consumption of either monosodium glutamate (MSG) or high-fat and high-fructose (HFF) diets changes the gut microbiome and hence contributes to development of several diseases. In this study, with an emphasis on kidney injury, hamsters were divided into 4 groups as follows: (1) hamsters fed with standard diet (control); (2) hamsters fed with standard diet and MSG in drinking water (MSG); (3) hamsters fed with high-fat and high-fructose diets (HFF), and (4) animals fed MSG+HFF. After 8 months, the animals were used for the study. Despite showing normal kidney function, hamsters fed with MSG+HFF exhibited signs of kidney damage as demonstrated by the highest expression levels of high-mobility group box-1 and kidney injury molecule-1 in kidney tissues, while slight changes of histopathological features in H&E-stained sections and normal levels of creatinine were observed, indicating possible early stages of kidney injury. Sequencing of the microbial 16S rRNA gene revealed that animals fed with the MSG+HFF diet had a higher ratio of gut Firmicutes/Bacteroidetes along with marked changes in abundance and diversity of gut microbiome compared to hamsters fed with MSG or HFF alone. In addition, 1H Nuclear magnetic resonance spectroscopy showed an elevation of urine p-cresol sulfate levels in the MSG+HFF group. These results indicate that consumption of both MSG and HFF increases the risk of kidney injury, induces gut dysbiosis and an increase in the amount of p-cresol sulfate in hamsters.

Topics: Animals; Bacteroidetes; Cresols; Cricetinae; Diet, Carbohydrate Loading; Diet, High-Fat; Dysbiosis; Firmicutes; Fructose; Gastrointestinal Microbiome; Hepatitis A Virus Cellular Receptor 1; HMGB1 Protein; Kidney; Male; Mesocricetus; Renal Insufficiency; RNA, Ribosomal, 16S; Sodium Glutamate; Sulfuric Acid Esters

Hydrophobic uremic toxins accumulate in patients with chronic kidney disease, contributing to a highly increased cardiovascular risk. The clearance of these uremic toxins using current hemodialysis techniques is limited due to their hydrophobicity and their high binding affinity to plasma proteins. Adsorber techniques may be an appropriate alternative to increase hydrophobic uremic toxin removal. We developed an extracorporeal, whole-blood bifunctional adsorber particle consisting of a porous, activated charcoal core with a hydrophilic polyvinylpyrrolidone surface coating. The adsorption capacity was quantified using analytical chromatography after perfusion of the particles with an albumin solution or blood, each containing mixtures of hydrophobic uremic toxins. A time-dependent increase in hydrophobic uremic toxin adsorption was depicted and all toxins showed a high binding affinity to the adsorber particles. Further, the particle showed a sufficient hemocompatibility without significant effects on complement component 5a, thrombin-antithrombin III complex, or thrombocyte concentration in blood in vitro, although leukocyte counts were slightly reduced. In conclusion, the bifunctional adsorber particle with cross-linked polyvinylpyrrolidone coating showed a high adsorption capacity without adverse effects on hemocompatibility in vitro. Thus, it may be an interesting candidate for further in vivo studies with the aim to increase the efficiency of conventional dialysis techniques.

Topics: Adsorption; Blood Cell Count; Charcoal; Cresols; Humans; Indican; Phenylacetates; Povidone; Renal Dialysis; Renal Insufficiency; Sulfuric Acid Esters; Uremia

Chronic kidney disease (CKD) is a major health problem worldwide. Indoxyl sulfate (IS) and p-cresyl sulfate (PCS) are highly protein-bound nephro-cardiovascular toxins, which are not efficiently removed through hemodialysis. The renal excretions of IS and PCS were mediated by organic anion transporters (OATs) such as OAT1 and OAT3. Green tea (GT) is a popular beverage containing plenty of catechins. Previous pharmacokinetic studies of teas have shown that the major molecules present in the bloodstream are the glucuronides/sulfates of tea catechins, which are putative substrates of OATs. Here we demonstrated that GT ingestion significantly elevated the systemic exposures of endogenous IS and PCS in rats with chronic renal failure (CRF). More importantly, GT also significantly increased the levels of serum creatinine (Cr) and blood urea nitrogen (BUN) in CRF rats. Mechanism studies indicated that the serum metabolites of GT (GTM) inhibited the uptake transporting functions of OAT1 and OAT3. In conclusion, GT inhibited the elimination of nephro-cardiovascular toxins such as IS and PCS, and deteriorated the renal function in CRF rats.

Topics: Adenine; Animals; Catechin; CHO Cells; Creatinine; Cresols; Cricetinae; Cricetulus; Disease Models, Animal; Glucuronides; HEK293 Cells; Humans; Indican; Kidney; Male; Organic Anion Transport Protein 1; Organic Anion Transporters, Sodium-Independent; Rats; Rats, Sprague-Dawley; Renal Insufficiency; Sulfates; Sulfuric Acid Esters; Tea; Toxins, Biological

p-Cresylsulfate (PCS), a protein-bound uraemic retention solute, is known to cause endothelial dysfunction and possibly plays a role in coronary atherosclerosis. Furthermore, the association among serum total PCS, major adverse cardiovascular events, and all-cause mortality were also found in previous studies. However, little is known about the relationship between total PCS level and prolonged QT interval. We assessed whether serum total PCS level is related with prolonged QT interval by measuring 12-lead electrocardiogram (ECG) recording in stable angina patients with early stage of renal failure.. Serum total PCS concentrations were measured by using the Ultra Performance LC System in 154 consecutive stable angina patients. A 12-lead ECG recording was obtained from each subject.. Patients with abnormal corrected QT (QTc) interval have higher median serum total PCS levels than patients with normal QTc interval. Statistically significant associations were observed between the serum total PCS levels and the QTc interval (r=0.217, P=0.007). Using multivariate and trend analyses, serum total PCS level was independently associated with QTc prolongation.. This study indicates that serum total PCS levels are significantly higher in the presence of abnormal QTc interval and are associated with the QTc prolongation. Whether total PCS plays a role in the pathogenesis of QTc prolongation requires future investigation.

Topics: Aged; Aged, 80 and over; Angina, Stable; Biomarkers; Cresols; Cross-Sectional Studies; Electrocardiography; Female; Follow-Up Studies; Humans; Long QT Syndrome; Male; Middle Aged; Renal Insufficiency; Sulfuric Acid Esters

p-Cresylsulphate (PCS), a protein-bound uraemic retention solute, is known to cause endothelial dysfunction and possibly plays a role in coronary atherosclerosis. We aimed to investigate the relationship of total PCS with traditional biomarkers associated with chronic coronary atherosclerosis. In addition, the relationship between serum total PCS levels and the severity of coronary artery stenosis was also explored.. Serum total PCS concentrations were measured by using the Ultra Performance LC System in 202 consecutive stable angina patients, and their associations with angiographic indexes of the number of diseased vessels and modified Gensini score were estimated. Patients with significant coronary artery stenosis have higher median serum total PCS levels than patients with normal coronary arteries. Statistically significant associations were observed between the serum total PCS levels and the number of diseased vessels (beta=0.261, p=0.0002), and modified Gensini score (beta=0.171, p=0.016). Using multivariate analysis, serum total PCS level was independently associated with the presence and severity of CAD.. This study indicates that serum total PCS levels are significantly higher in the presence of CAD and are correlated with the severity of the disease, which suggest that increased serum total PCS may be involved in the pathogenesis of coronary atherosclerosis.

Topics: Aged; Angina Pectoris; Coronary Angiography; Coronary Artery Disease; Cresols; Cross-Sectional Studies; Female; Gene Expression Regulation; Humans; Male; Middle Aged; Multivariate Analysis; Regression Analysis; Renal Insufficiency; Sulfuric Acid Esters

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