Indoxyl sulfate, a protein-bound uremic toxin, leads to CKD (chronic kidney disease) progression and its complications through the activation of AhR (aryl hydrocarbon receptor) and RAS (renin-angiotensin system). Inhibition of these pathways may slow the development of CKD and CKD-associated complications.
Indican ; Kidney ; Receptors, Aryl Hydrocarbon* ; Renal Insufficiency, Chronic ; Renin-Angiotensin System*

BACKGROUND: We investigated the long-term effect of AST-120, which has been proposed as a therapeutic option against renal disease progression, in patients with advanced chronic kidney disease (CKD). METHODS: We performed post-hoc analysis with a per-protocol group of the K-STAR study (Kremezin study against renal disease progression in Korea) that randomized participants into an AST-120 and a control arm. Patients in the AST-120 arm were given 6 g of AST-120 in three divided doses, and those in both arms received standard conventional treatment. RESULTS: The two arms did not differ significantly in the occurrence of composite primary outcomes (log-rank P = 0.41). For AST-120 patients with higher compliance, there were fewer composite primary outcomes: intermediate tertile hazard ratio (HR) 0.62, 95% confidence interval (CI) 0.38 to 1.01, P = 0.05; highest tertile HR 0.436, 95% CI 0.25 to 0.76, P = 0.003. The estimated glomerular filtration rate level was more stable in the AST-120 arm, especially in diabetic patients. At one year, the AST-120-induced decrease in the serum indoxyl sulfate concentration inversely correlated with the occurrence of composite primary outcomes: second tertile HR 1.59, 95% CI 0.82 to 3.07, P = 0.17; third tertile HR 2.11, 95% CI 1.07 to 4.17, P = 0.031. Furthermore, AST-120 showed a protective effect against the major cardiovascular adverse events (HR 0.51, 95% CI 0.26 to 0.99, P = 0.046). CONCLUSION: Long-term use of AST-120 has potential for renal protection, especially in diabetic patients, as well as cardiovascular benefits. Reduction of the serum indoxyl sulfate level may be used to identify patients who would benefit from AST-120 administration.
Arm ; Compliance ; Disease Progression* ; Glomerular Filtration Rate ; Humans ; Indican ; Korea* ; Renal Insufficiency, Chronic

Purple urine bag syndrome (PUBS) is a rare phenomenon where the urinary catheter and bag turns purple following catheterization. The colors are formed from the substrate indoxyl sulfate (indican). PUBS is associated with urinary tract infections induced by the reaction of some species of bacteria with indoxyl sulfatase. We report here in a case of purple urine bag syndrome.
Bacteria ; Catheterization ; Catheters ; Indican ; Urinary Catheters ; Urinary Tract ; Urinary Tract Infections

PURPOSE: AST-120 is known to delay progression of chronic kidney disease (CKD) when combined with other proven therapy. AST-120 is an oral adsorbent for uremic toxin, such as indoxyl sulfate from the gastrointestinal tract. There have been a lot of studies to show its effect in other countries, but there are few studies done in Korea yet. METHODS: 195 patients were included in the study (mean age, 64+/-14 years; diabetes mellitus (DM), 104 patients; male, 130 patients). The patients with CKD who started AST-120 and maintained the medication for at least 6 months were enrolled. The patients' laboratory results for 6 months before and after administrating AST-120 was surveyed. Then the rate of patients' renal functional deterioration was compared before and after AST-120. In addition, adverse effects during the medication were surveyed. RESULTS: There were no statistically significant differences in laboratory data between before and after AST-120 administration. But, after administrating AST-120, the renal deterioration slope has blunted significantly from -0.0123+/-0.0318 to -0.0013+/-0.0184 dL/mg/month (p<0.01) in 1/sCr and from -1.1423+/-2.3906 to 0.0639+/-1.3825 ml/min/1.73m2/month (p<0.01) in estimated glomerular filtration rate (eGFR). There were no differences between DM and non-DM patients in the effect of AST-120, as well as ages over 70 and below 70. There were no serious adverse effects during medication. CONCLUSION: This study showed that AST-120 had additive effect on retarding the CKD progression when combined with established therapy regardless of DM and ages without serious adverse effects.
Carbon ; Diabetes Mellitus ; Gastrointestinal Tract ; Glomerular Filtration Rate ; Humans ; Indican ; Indoles ; Kidney Failure, Chronic ; Korea ; Male ; Oxides ; Renal Insufficiency, Chronic

Cardiovascular disease is one of the most common complications and the main cause of death in patients with chronic kidney disease. Uremic toxins are the primary cause of cardiovascular disease in renal insufficiency. In patients with chronic kidney disease, the protein-bound uremic toxins represented by indoxyl sulfate are difficult to be removed by conventional dialysis and are extremely toxic. In recent years, studies have confirmed that the occurrence of cardiovascular disease induced by chronic kidney disease is closely related to the accumulation of indoxyl sulfate. Indoxyl sulfate can induce oxidative stress to cause endothelial injury, smooth muscle cell proliferation and migration, and promote the occurrence of atherosclerosis, thereby affecting multiple systems throughout the body. This article reviews the research progress of uremic toxin indoxyl sulfate in end-stage renal diseases associated cardiovascular diseases.
Cardiovascular Diseases ; complications ; physiopathology ; Humans ; Indican ; toxicity ; Kidney Failure, Chronic ; complications ; physiopathology ; Oxidative Stress ; Toxins, Biological ; toxicity

BACKGROUND: Removal of uremic toxins such as indoxyl sulfate by AST-120 is known to improve renal function and delay the initiation of dialysis in patients with advanced chronic kidney disease. However, it is unclear whether the addition of AST-120 to conventional treatments is effective in delaying the progression of renal dysfunction in patients with diabetic nephropathy. METHODS: A total of 100 patients with type 2 diabetes and renal dysfunction (serum creatinine levels ranging from 1.5 to 3.0 mg/dL) were recruited from eight centers in Korea and treated with AST-120 (6 g/day) for 24 weeks. The primary endpoint was improvement in renal function measured as the gradient of the reciprocal serum creatinine level (1/sCr) over time (i.e., the ratio of 1/sCr time slope for post- to pre-AST-120 therapy). A response was defined as a ratio change of the regression coefficient of 1/sCr ≤ 0.90. RESULTS: Renal function improved in 80.3% of patients (61/76) after 24 weeks of AST-120 treatment. There were no differences between responder and non-responder groups in baseline characteristics except for diastolic blood pressure (73.5 ± 9.5 mmHg in the responder group vs. 79.3 ± 11.1 mmHg in the non-responder group; P = 0.046). Serum lipid peroxidation level decreased significantly in the responder group (from 2.25 ± 0.56 μmol/L to 1.91 ± 0.72 μmol/L; P = 0.002) but not in the non-responder group. CONCLUSION: The addition of AST-120 to conventional treatments may delay the progression of renal dysfunction in diabetic nephropathy. The antioxidant effect of AST-120 might contribute to improvement in renal function.
Antioxidants ; Blood Pressure ; Creatinine ; Diabetic Nephropathies ; Dialysis ; Humans ; Indican ; Korea ; Lipid Peroxidation ; Oxidative Stress ; Prospective Studies ; Renal Insufficiency, Chronic

OBJECTIVETo investigate the pathologies of aortic root atherosclerotic lesion in uremic apoE-/- mice and explore the effect of serum from patients with chronic renal insufficiency (CRI) and the uremic toxin, indoxyl sulfate (IS), on the expression of cholesterol transporting receptors and lipid accumulation in macrophages in vitro.

METHODSThe uremic apoE-/- mouse model was established by surgical operation. Frozen sections of the aortic root were collected from uremic apoE-/- mice, sham-operated apoE-/- mice and C57BL/6J mice and stained with oil red O to calculate the relative area of atherosclerotic plaque. Murine macrophage RAW264.7 cell line was treated for 12 h with different concentrations of IS or serum samples from CRI patients and healthy individuals, and the mRNA expressions of cholesterol transporting receptors (SR-A1, CD36, ABCA1, ABCG1 and SR-B1) were detected. After treatment for 24 h, the cells were induced into foam cells to determine lipid contents using oil red O staining.

RESULTSThe relative area of the atherosclerotic plaques in the aortic root increased significantly in uremic apoE-/- mice compared with that in sham-operated apoE-/- mice. CRI serum (5%) and IS (250 µmol/L) obviously increased the mRNA expression of CD36 and lipid accumulation in the macrophages, but did not affect the mRNA expression of other cholesterol transporting receptors.

CONCLUSIONCRI can accelerate the progression of atherosclerosis through the mechanism that IS in CRI serum promotes lipid accumulation in macrophages by enhancing the mRNA expression of CD36, which contributes to the formation of foam cells.

Animals ; Apolipoproteins E ; Cell Line ; Foam Cells ; chemistry ; Humans ; Indican ; pharmacology ; Lipids ; chemistry ; Macrophages ; chemistry ; Mice ; Mice, Inbred C57BL ; Plaque, Atherosclerotic ; pathology ; Renal Insufficiency, Chronic ; blood

PURPOSE: Indoxyl sulfate and p-cresyl sulfate are important protein-bound uremic retention solutes whose levels can be partially reduced by renal replacement therapy. These solutes originate from intestinal bacterial protein fermentation and are associated with cardiovascular outcomes and chronic kidney disease progression. The aims of this study were to investigate the levels of indoxyl sulfate and p-cresyl sulfate as well as the effect of probiotics on reducing the levels of uremic toxins in pediatric patients on dialysis. METHODS: We enrolled 20 pediatric patients undergoing chronic dialysis; 16 patients completed the study. The patients underwent a 12-week regimen of VSL#3, a high-concentration probiotic preparation, and the serum levels of indoxyl sulfate and p-cresyl sulfate were measured before treatment and at 4, 8, and 12 weeks after the regimen by using fluorescence liquid chromatography. To assess the normal range of indoxyl sulfate and p-cresyl sulfate we enrolled the 16 children with normal glomerular filtration rate who had visited an outpatient clinic for asymptomatic microscopic hematuria that had been detected by a school screening in August 2011. RESULTS: The baseline serum levels of indoxyl sulfate and p-cresyl sulfate in the patients on chronic dialysis were significantly higher than those in the children with microscopic hematuria. The baseline serum levels of p-cresyl sulfate in the peritoneal dialysis group were significantly higher than those in the hemodialysis group. There were no significant changes in the levels of these uremic solutes after 12-week VSL#3 treatment in the patients on chronic dialysis. CONCLUSION: The levels of the uremic toxins p-cresyl sulfate and indoxyl sulfate are highly elevated in pediatric patients on dialysis, but there was no significant effect by probiotics on the reduction of uremic toxins in pediatric dialysis patients. Therefore, studies for other medical intervention to reduce uremic toxins are also necessary in pediatric patients on dialysis.
Ambulatory Care Facilities ; Bacterial Proteins ; Child ; Chromatography, Liquid ; Dialysis ; Fermentation ; Fluorescence ; Glomerular Filtration Rate ; Hematuria ; Humans ; Indican ; Indoles ; Mass Screening ; Peritoneal Dialysis ; Probiotics ; Reference Values ; Renal Dialysis ; Renal Insufficiency, Chronic ; Renal Replacement Therapy ; Retention (Psychology)

OBJECTIVE: To investigate the inhibitory effect of Zhenwu Decoction on ventricular hypertrophy in rats with uremic cardiomyopathy and explore the mechanism. METHODS: Cardiocytes isolated from suckling rats were divided into control group and indoxyl sulfate (IS) group, and the protein synthesis was assayed with [H]- leucine incorporation and cellular protein expressions were detected using Western blotting. Fifty SD rats were randomly divided into sham operation group, model group, and low- and high-dose Zhenwu Decoction treatment groups, and except for those in the sham operation group, all the rats underwent 5/6 nephrectomy. Four weeks after the operation, the rats in low- and high-dose treatment groups were given Zhenwu Decoction gavage at the dose of 4.5 g/kg and 13.5 g/kg, respectively; the rats in the sham-operated and model groups were given an equal volume of distilled water. After 4 weeks of treatment, serum levels of IS were determined, and cardiac and ventricular mass indexes were measured in the rats; cardiac ultrasound was performed and Western blotting was used to measure the expressions of BNP, p-ERK1/2, p-p38 and p-JNK in the myocardium. RESULTS: Rat cardiomyocytes treated with IS showed significantly enhanced protein synthesis and increased expression levels of BNP, p-erk1/2, and p-p38 as compared with the control cells ( < 0.01), but the expression of p-jnk was comparable between the two groups. In the animal experiment, the rats in the model group showed significantly increased serum creatinine (SCr) and urea nitrogen (BUN) levels, 24-h urine protein (24 hUpro), plasma IS level, left ventricular mass index (LVMI) and whole heart mass index (HMI) compared with those in the sham group ( < 0.01); Both LVESD and LVEDD were significantly reduced and LVAWS, LVAWD, LVPWS and LVPWD were significantly increased in the model rat, which also presented with obvious cardiomyocyte hypertrophy and increased myocardial expressions of BNP, p-ERK1/2, p-p38 and p-jnk ( < 0.01). Compared with the rats in the model group, the rats treated with low-dose and high-dose Zhenwu Decoction had significantly lowered levels of SCr, BUN, 24 hUpro and IS ( < 0.05) and decreased LVMI and HMI; LVESD, LVEDD, LVPWS, LVAWS, and LVAWD were improved more obviously in the high-dose group, and the myocardial expressions of BNP, p-ERK1/2, p-p38 and p-JNK was significantly downregulated after the treatment. CONCLUSIONS Zhenwu Decoctin can reduce plasma IS levels and inhibit ventricular hypertrophy to delay ventricular remodeling in rats with uremic cardiomyopathy.
Animals ; Blood Urea Nitrogen ; Cardiomegaly ; prevention & control ; Cardiomyopathies ; complications ; Creatinine ; blood ; Drugs, Chinese Herbal ; pharmacology ; Heart Ventricles ; Indican ; blood ; pharmacology ; Myocytes, Cardiac ; drug effects ; metabolism ; Nephrectomy ; Random Allocation ; Rats ; Rats, Sprague-Dawley

BACKGROUND: The renal function of individuals is one of the reasons for the variations in therapeutic response to various drugs. Patients with renal impairment are often exposed to drug toxicity, even with drugs that are usually eliminated by hepatic metabolism. Previous study has reported an increased plasma concentration of indoxyl sulfate and decreased plasma concentration of 4β-hydroxy (OH)-cholesterol in stable kidney transplant recipients, implicating indoxyl sulfate as a cytochrome P450 (CYP) inhibiting factor. In this study, we aimed to evaluate the impact of renal impairment severity-dependent accumulation of indoxyl sulfate on hepatic CYP3A activity using metabolic markers. METHODS: Sixty-six subjects were enrolled in this study; based on estimated glomerular filtration rate (eGFR), they were classified as having mild, moderate, or severe renal impairment. The plasma concentration of indoxyl sulfate was quantified using liquid chromatography-mass spectrometry (LC-MS). Urinary and plasma markers (6β-OH-cortisol/cortisol, 6β-OH-cortisone/cortisone, 4β-OH-cholesterol) for hepatic CYP3A activity were quantified using gas chromatography-mass spectrometry (GC-MS). The total plasma concentration of cholesterol was measured using the enzymatic colorimetric assay to calculate the 4β-OH-cholesterol/cholesterol ratio. The correlation between variables was assessed using Pearson's correlation test. RESULTS: There was a significant negative correlation between MDRD eGFR and indoxyl sulfate levels. The levels of urinary 6β-OH-cortisol/cortisol and 6β-OH-cortisone/cortisone as well as plasma 4β-OH-cholesterol and 4β-OH-cholesterol/cholesterol were not correlated with MDRD eGFR and the plasma concentration of indoxyl sulfate. CONCLUSION: Hepatic CYP3A activity may not be affected by renal impairment-induced accumulation of plasma indoxyl sulfate.
Cholesterol ; Cytochrome P-450 CYP3A* ; Cytochrome P-450 Enzyme System* ; Cytochromes* ; Drug-Related Side Effects and Adverse Reactions ; Gas Chromatography-Mass Spectrometry ; Glomerular Filtration Rate ; Humans ; Indican ; Kidney ; Metabolism ; Plasma ; Spectrum Analysis ; Transplant Recipients