How renal toxins respond to renal function deterioration and oral toxic adsorbent in pH-controlled releasing capsule.

The number of patients with chronic kidney disease (CKD) is increasing. Oral toxin adsorbents may provide some value. Several uremic toxins, including indoxyl sulfate (IS), p-cresol (PCS), acrolein, per- and poly-fluoroalkyl substances (PFAS), and inflammation markers (interleukin 6 [IL-6] and tumor necrosis factor [TNF]-alpha) have been shown to be related to CKD progression. A total of 81 patients taking oral activated charcoal toxin adsorbents (AC-134), which were embedded in capsules that dissolved in the terminal ileum, three times a day for 1 month, were recruited. The renal function, hemoglobulin (Hb), inflammation markers, three PFAS (PFOA, PFOS, and PFNA), and acrolein were quantified. Compared with the baseline, an improved glomerular filtration rate (GFR) and significantly lower acrolein were noted. Furthermore, the CKD stage 4 and 5 group had significantly higher concentrations of IS, PCS, IL-6, and TNF but lower levels of Hb and PFAS compared with the CKD Stage 3 group at baseline and after the intervention. Hb was increased only in the CKD Stage 3 group after the trial (p = .032). Acrolein did not differ between the different CKD stage groups. Patients with improved GFR (responders) (about 77%) and nonresponders had similar baseline GFR. Responders had higher acrolein and PFOA levels throughout the study and a more significant reduction in acrolein, indicating a better digestion function. Both the higher PFOA and lower acrolein may be related to improved eGFR (and possibly to improvements in proteinuria, which we did not measure. Proteinuria is associated with PFAS loss in the urine), AC-134 showed the potential to improve the GFR and decrease acrolein, which might better indicate renal function change. Future studies are needed with longer follow-ups.

P-cresol and Indoxyl Sulfate Impair Osteogenic Differentiation by Triggering Mesenchymal Stem Cell Senescence.

Chronic kidney disease (CKD) patients obtained high levels of uremic toxins progressively develop several complications including bone fractures. Protein-bound uremic toxins especially p-cresol and indoxyl sulfate are hardly eliminated due to their high molecular weight. Thus, the abnormality of bone in CKD patient could be potentially resulted from the accumulation of uremic toxins. To determine whether protein-bound uremic toxins have an impact on osteogenesis, mesenchymal stem cells were treated with either p-cresol or indoxyl sulfate under in vitro osteogenic differentiation. The effects of uremic toxins on MSC-osteoblastic differentiation were investigated by evaluation of bone phenotype. The results demonstrated that p-cresol and indoxyl sulfate down-regulated the transcriptional level of collagen type I, deceased alkaline phosphatase activity, and impaired mineralization of MSC-osteoblastic cells. Furthermore, p-cresol and indoxyl sulfate gradually increased senescence-associated beta-galactosidase positive cells while upregulated the expression of p21 which participate in senescent process. Our findings clearly revealed that the presence of uremic toxins dose-dependently influenced a gradual deterioration of osteogenesis. The effects partially mediate through the activation of senescence-associated gene lead to the impairment of osteogenesis. Therefore, the management of cellular senescence triggered by uremic toxins could be considered as an alternative therapeutic approach to prevent bone abnormality in CKD patients.

Indoxyl sulfate induces intestinal barrier injury through IRF1-DRP1 axis-mediated mitophagy impairment.

Rationale: The dysfunctional gut-kidney axis forms a vicious circle, which eventually becomes a catalyst for the progression of chronic kidney disease (CKD) and occurrence of related complications. However, the pathogenic factors of CKD-associated intestinal dysfunction and its mechanism remain elusive. Methods: We first identified the protein-bound uremic toxin indoxyl sulfate (IS) as a possible contributor to intestinal barrier injury. Transepithelial electrical resistance, permeability assay and transmission electron microscopy were carried out to evaluate the damaging effect of IS on intestinal barrier in intestinal epithelial cells, IS-injected mice and CKD mice. In vitro and in vivo experiments were performed to investigate the role of IS in intestinal barrier injury and the underlying mechanism. Finally, CKD mice treated with AST-120 (an oral adsorbent for IS) and gene knockout mice were used to verify the mechanism and to explore possible interventions for IS-induced intestinal barrier injury. Results: Transepithelial electrical resistance and the expressions of tight junction-related genes were significantly suppressed by IS in intestinal epithelial cells. In vitro experiments demonstrated that IS inhibited the expression of dynamin-related protein 1 (DRP1) and mitophagic flux, whereas DRP1 overexpression attenuated IS-induced mitophagic inhibition and intestinal epithelial cell damage. Furthermore, IS suppressed DRP1 by upregulating the expression of interferon regulatory factor 1 (IRF1), and IRF1 could directly bind to the promoter region of DRP1. Additionally, the decreased expression of DRP1 and autophagosome-encapsulated mitochondria were observed in the intestinal tissues of CKD patients. Administration of AST-120 or genetic knockout of IRF1 attenuated IS-induced DRP1 reduction, mitophagic impairment and intestinal barrier injury in mice. Conclusions: These findings suggest that reducing IS accumulation or targeting the IRF1-DRP1 axis may be a promising therapeutic strategy for alleviating CKD-associated intestinal dysfunction.

Longitudinal metabolic and gut bacterial profiling of pregnant women with previous bariatric surgery.

OBJECTIVE: Due to the global increase in obesity rates and success of bariatric surgery in weight reduction, an increasing number of women now present pregnant with a previous bariatric procedure. This study investigates the extent of bariatric-associated metabolic and gut microbial alterations during pregnancy and their impact on fetal development. DESIGN: A parallel metabonomic (molecular phenotyping based on proton nuclear magnetic resonance spectroscopy) and gut bacterial (16S ribosomal RNA gene amplicon sequencing) profiling approach was used to determine maternal longitudinal phenotypes associated with malabsorptive/mixed (n=25) or restrictive (n=16) procedures, compared with women with similar early pregnancy body mass index but without bariatric surgery (n=70). Metabolic profiles of offspring at birth were also analysed. RESULTS: Previous malabsorptive, but not restrictive, procedures induced significant changes in maternal metabolic pathways involving branched-chain and aromatic amino acids with decreased circulation of leucine, isoleucine and isobutyrate, increased excretion of microbial-associated metabolites of protein putrefaction (phenylacetlyglutamine, p-cresol sulfate, indoxyl sulfate and p-hydroxyphenylacetate), and a shift in the gut microbiota. The urinary concentration of phenylacetylglutamine was significantly elevated in malabsorptive patients relative to controls (p=0.001) and was also elevated in urine of neonates born from these mothers (p=0.021). Furthermore, the maternal metabolic changes induced by malabsorptive surgery were associated with reduced maternal insulin resistance and fetal/birth weight. CONCLUSION: Metabolism is altered in pregnant women with a previous malabsorptive bariatric surgery. These alterations may be beneficial for maternal outcomes, but the effect of elevated levels of phenolic and indolic compounds on fetal and infant health should be investigated further.

Specific Urinary Metabolites in Malignant Melanoma.

Background and objectives: Melanin, which has a confirmed role in melanoma cell behaviour, is formed in the process of melanogenesis and is synthesized from tryptophan, L-tyrosine and their metabolites. All these metabolites are easily detectable by chromatography in urine. Materials and Methods: Urine samples of 133 individuals (82 malignant melanoma patients and 51 healthy controls) were analysed by reversed-phase high-performance liquid chromatography (RP-HPLC). The diagnosis of malignant melanoma was confirmed histologically. Results: Chromatograms of melanoma patients showed increased levels of 5,6-dihydroxyindole-2-carboxylic acid, vanilmandelic acid, homovanilic acid, tryptophan, 5-hydroxyindole-3-acetic acid, and indoxyl sulphate compared to healthy controls. Concentration of indoxyl sulphate, homovanilic acid and tryptophan were significantly increased even in the low clinical stage 0 of the disease (indoxyl sulphate, homovanilic acid and tryptophan in patients with clinical stage 0 vs. controls expressed as medium/ interquartile range in µmol/mmol creatinine: 28.37/15.30 vs. 5.00/6.91; 47.97/33.08 vs. 7.33/21.25; and 16.38/15.98 vs. 3.46/6.22, respectively). Conclusions: HPLC detection of metabolites of L-tyrosine and tryptophan in the urine of melanoma patients may play a significant role in diagnostics as well as a therapeutic strategy of melanoma cancer.

Assessment of urinary 3-indoxyl sulfate as a marker for gut microbiota diversity and abundance of Clostridiales.

OBJECTIVES: After allogeneic hematopoietic stem cell transplantation (allo-HCT), urinary levels of 3-indoxyl sulfate (3-IS) correlate with the relative abundance of bacteria from the class Clostridia (RAC), and antibiotic treatment is considered the major determinant of this outcome. A high RAC has been associated with favorable outcome after allo-HCT and protection from Clostridium difficile infection (CDI). We assessed correlations between alpha diversity, RAC and urinary 3-IS levels in a non-allo-HCT clinical cohort of antibiotic treated patients to further explore 3-IS as a biomarker of reduced diversity and predisposition to CDI. METHODS: Fecal and urinary specimens were analyzed from 40 non-allo-HCT hospitalized patients before and 9 ± 2 days after initiation of intravenous antibiotic treatment. Fecal microbiota were analyzed by 16s RNA sequencing and urinary 3-IS was analyzed by liquid chromatography-tandem mass spectrometry. Receiver operating characteristic (ROC) analysis was performed to assess the predictive value of 3-IS. RESULTS: At a RAC cutoff of <30%, the binary logarithm of 3-IS (medium 3-IS: ≤2.5; high 3-IS: >2.5) was predictive with an accuracy of 82% (negative predictive value: 87%, positive predictive value 67%). Accuracy was improved by combing antibiotic history with 3-IS levels (accuracy 89%, npv 88%, ppv 92%). CONCLUSION: In conjunction with patient antibiotic history, 3-IS is a candidate marker to predict RAC.

Could resistant starch supplementation improve inflammatory and oxidative stress biomarkers and uremic toxins levels in hemodialysis patients? A pilot randomized controlled trial.

An imbalance of gut microbiota is considered a new cardiovascular risk factor for chronic kidney disease (CKD) patients, since it is directly associated with increased uremic toxin production, inflammation and oxidative stress. Strategies such as prebiotic supplementation have been suggested to mitigate these complications. We hypothesized that prebiotic-resistant starch could ameliorate uremic toxins levels, oxidative stress, and inflammatory states in hemodialysis (HD) patients. This pilot study evaluated 31 HD patients assigned to either resistant starch (16 g of resistant starch Hi-Maize® 260) or placebo (manioc flour) supplementation, which they received for 4 weeks on alternate days through cookies on dialysis days and powder in a sachet on non-dialysis days. Levels of interleukin (IL)-6, high-sensitive C-reactive protein, thiobarbituric acid reactive substances plasma (TBARS), protein carbonylation, indoxyl sulfate (IS) and p-cresyl sulfate were measured. Anthropometric and biochemical parameters, as well as, food intake were also evaluated. As expected, resistant starch group increased fiber intake (p > 0.01), in addition the prebiotic supplementation reduced IL-6 (p = 0.01), TBARS (p > 0.01), and IS (p > 0.01) plasma levels. No significant differences were evident in the placebo group. Prebiotic-resistant starch supplementation seems to be a promising nutritional strategy to improve inflammation, oxidative stress and to reduce IS plasma levels in CKD patients on HD.

Uremic Toxins Activates Na/K-ATPase Oxidant Amplification Loop Causing Phenotypic Changes in Adipocytes in In Vitro Models.

BACKGROUND: Oxidant stress plays a key role in the development of chronic kidney disease (CKD). Experimental CKD leads to accumulation of uremic toxins (UT) in the circulation resulting in increased ROS production, which in turn, is known to activate the Na/K-ATPase/ROS amplification loop. Studies in a murine model of obesity have shown that increased oxidative stress in plasma is due to increased ROS and cytokine production from dysfunctional adipocytes. Therefore, we hypothesized that adipocytes exposed to UTs will activate the Na/K-ATPase oxidant amplification loop causing redox imbalance and phenotypic alterations in adipocytes. We also aimed to demonstrate that the Na/K-ATPase signaling antagonist, pNaKtide, attenuates these pathophysiological consequences. METHODS: In the first set of experiments, 3T3-L1 murine pre-adipocytes were treated with varying concentrations of UTs, indoxyl sulfate (IS) (50, 100 and 250 µM) and p-cresol (50, 100 and 200 µM), with or without pNaKtide (0.7 µM) for five days in adipogenic media, followed by Oil Red O staining to study adipogenesis. RT-PCR analysis was performed to study expression of adipogenic, apoptotic and inflammatory markers, while DHE staining evaluated the superoxide levels in UT treated cells. In a second set of experiments, visceral fat was obtained from the West Virginian population. MSCs were isolated and cultured in adipogenic media for 14 days, which was treated with indoxyl sulfate (0, 25, 50 and 100 µM) with or without pNaKtide (1 µM). MSC-derived adipocytes were evaluated for morphological and molecular analysis of the above markers. RESULTS: Our results demonstrated that 3T3-L1 cells and MSCs-derived adipocytes, treated with UTs, exhibited a significant decrease in adipogenesis and apoptosis through activation of the Na/K-ATPase/ROS amplification loop. The treatment with pNaKtide in 3T3-L1 cells and MSC-derived adipocytes negated the effects of UTs and restored cellular redox in adipocytes. We noted a varying effect of pNaKtide, in adipocytes treated with UTs, on inflammatory markers, adipogenic marker and superoxide levels in 3T3-L1 cells and MSC-derived adipocytes. CONCLUSIONS: This study demonstrates for the first time that the Na/K-ATPase/ROS amplification loop activated by elevated levels of UTs has varying effect on phenotypic alterations in adipocytes in various in vitro models. Thus, we propose that, if proven in humans, inhibition of Na/K-ATPase amplification of oxidant stress in CKD patients may ultimately be a novel way to combat adipocyte dysfunction and metabolic imbalance in these patients.

Identification of ABCG2 as an Exporter of Uremic Toxin Indoxyl Sulfate in Mice and as a Crucial Factor Influencing CKD Progression.

Chronic kidney disease (CKD) patients accumulate uremic toxins in the body, potentially require dialysis, and can eventually develop cardiovascular disease. CKD incidence has increased worldwide, and preventing CKD progression is one of the most important goals in clinical treatment. In this study, we conducted a series of in vitro and in vivo experiments and employed a metabolomics approach to investigate CKD. Our results demonstrated that ATP-binding cassette transporter subfamily G member 2 (ABCG2) is a major transporter of the uremic toxin indoxyl sulfate. ABCG2 regulates the pathophysiological excretion of indoxyl sulfate and strongly affects CKD survival rates. Our study is the first to report ABCG2 as a physiological exporter of indoxyl sulfate and identify ABCG2 as a crucial factor influencing CKD progression, consistent with the observed association between ABCG2 function and age of dialysis onset in humans. The above findings provided valuable knowledge on the complex regulatory mechanisms that regulate the transport of uremic toxins in our body and serve as a basis for preventive and individualized treatment of CKD.

Moderate Increase of Indoxyl Sulfate Promotes Monocyte Transition into Profibrotic Macrophages.

OBJECTIVE: The uremic toxin Indoxyl-3-sulphate (IS), a ligand of Aryl hydrocarbon Receptor (AhR), raises in blood during early renal dysfunction as a consequence of tubular damage, which may be present even when eGFR is normal or only moderately reduced, and promotes cardiovascular damage and monocyte-macrophage activation. We previously found that patients with abdominal aortic aneurysms (AAAs) have higher CD14+CD16+ monocyte frequency and prevalence of moderate chronic kidney disease (CKD) than age-matched control subjects. Here we aimed to evaluate the IS levels in plasma from AAA patients and to investigate in vitro the effects of IS concentrations corresponding to mild-to-moderate CKD on monocyte polarization and macrophage differentiation. METHODS: Free IS plasma levels, monocyte subsets and laboratory parameters were evaluated on blood from AAA patients and eGFR-matched controls. THP-1 monocytes, treated with IS 1, 10, 20 µM were evaluated for CD163 expression, AhR signaling and then induced to differentiate into macrophages by PMA. Their phenotype was evaluated both at the stage of semi-differentiated and fully differentiated macrophages. AAA and control sera were similarly used to treat THP-1 monocytes and the resulting macrophage phenotype was analyzed. RESULTS: IS plasma concentration correlated positively with CD14+CD16+ monocytes and was increased in AAA patients. In THP-1 cells, IS promoted CD163 expression and transition to macrophages with hallmarks of classical (IL-6, CCL2, COX2) and alternative phenotype (IL-10, PPARγ, TGF-ß, TIMP-1), via AhR/Nrf2 activation. Analogously, AAA sera induced differentiation of macrophages with enhanced IL-6, MCP1, TGF-ß, PPARγ and TIMP-1 expression. CONCLUSION: IS skews monocyte differentiation toward low-inflammatory, profibrotic macrophages and may contribute to sustain chronic inflammation and maladaptive vascular remodeling.

How's your microbiota? Let's check your urine.

In this issue of Blood, Weber and colleagues demonstrate that in the first 10 days following allogeneic hematopoietic transplantation, urinary 3-indoxyl sulfate is a biomarker of intestinal microbiota health and predicts reduced intestinal graft-versus-host disease (GVHD) and treatment-related mortality, as well as improved overall survival.

Low urinary indoxyl sulfate levels early after transplantation reflect a disrupted microbiome and are associated with poor outcome.

Indole, which is produced from l-tryptophan by commensal bacteria expressing tryptophanase, not only is an important intercellular signal in microbial communities, but also modulates mucosal barrier function and expression of pro- and anti-inflammatory genes by intestinal epithelial cells. Here, we hypothesized that decreased urinary excretion of 3-indoxyl sulfate (3-IS), the major conjugate of indole found in humans, may be a marker of gut microbiota disruption and increased risk of developing gastrointestinal (GI) graft-versus-host-disease. Using liquid chromatography/tandem mass spectrometry, 3-IS was determined in urine specimens collected weekly within the first 28 days after allogeneic stem cell transplantation (ASCT) in 131 patients. Low 3-IS levels within the first 10 days after ASCT were associated with significantly higher transplant-related mortality (P = .017) and worse overall survival (P = .05) 1 year after ASCT. Least absolute shrinkage and selection operator regression models trained on log-normalized counts of 763 operational taxonomic units derived from next-generation sequencing of the hypervariable V3 region of the 16S ribosomal RNA gene showed members of the families of Lachnospiraceae and Ruminococcaceae of the class of Clostridia to be associated with high urinary 3-IS levels, whereas members of the class of Bacilli were associated with low 3-IS levels. Risk factors of early suppression of 3-IS levels were the type of GI decontamination (P = .01), early onset of antibiotic treatment (P = .001), and recipient NOD2/CARD15 genotype (P = .04). In conclusion, our findings underscore the relevance of microbiota-derived indole and metabolites thereof in mucosal integrity and protection from inflammation.

Hepatic sulfotransferase as a nephropreventing target by suppression of the uremic toxin indoxyl sulfate accumulation in ischemic acute kidney injury.

Ischemia/reperfusion (I/R)-induced acute kidney injury (AKI) is evoked by diverse pathophysiological conditions and/or surgical procedures. Here, we evaluated the nephropreventive effect of sulfotransferase (SULT) inhibitors, quercetin, and resveratrol, which hamper hepatic indoxyl sulfate (IS) production. I/R of the kidney caused severe renal injury with marked accumulation of serum and renal IS and urinary excretion of kidney injury molecule-1. Oral administration of AST-120 resulted in a significant restoration of kidney injury, suggesting that uremic toxins, which can be suppressed or adsorbed by AST-120 in the intestine, contribute to the progression or development of I/R-induced AKI. Oral administration of resveratrol or quercetin, SULT inhibitors, suppressed IS accumulation, accompanied by significant amelioration of renal dysfunction. The expression of nuclear factor E2-related factor 2 (Nrf2) in the renal nuclear fractions was markedly elevated by renal I/R, but suppressed by treatment with SULT inhibitors. IS is primarily taken up by HK-2 cells derived from human proximal tubular cells via organic anion transporters, which then evokes activation of Nrf2, most likely due to intracellular oxidative stress. Renal basolateral organic anion transporters OAT1 and OAT3, which mediate renal tubular uptake of IS in basolateral membrane, were markedly downregulated by renal I/R, but restored by SULT inhibitors. Our results suggest that renal accumulation of IS in ischemic AKI induces oxidative stress and downregulation of organic anion transporters resulting in kidney damage, which could be restored to some extent by inhibiting hepatic SULT activity as a nephropreventive target.

Steady-state and time-resolved fluorescence spectroscopic characterization of urine of healthy subjects and cervical cancer patients.

Steady-state and time-resolved fluorescence spectroscopy were employed in the discrimination of cervical cancer patients from healthy subjects using urine samples. Fluorescence emission at 390 and 440 nm was considered to monitor the fluorescence of indoxyl sulfate and neopterin. Significant spectral differences were observed between healthy and cancer subjects. Different ratio parameters were calculated from the spectral intensity at 280- and 350-nm excitation and were subjected to stepwise linear discriminant analysis. In total, 84.0% of samples were correctly classified at 280 nm and 96.4% were correctly classified at 350 nm. The fluorescence decay kinetics of urine samples at 390-nm emission was best described by bi- exponential fits, whereas the decay characteristics at 440 nm of urine samples was best explained by bi-exponential fits and, in some cases, by tri-exponential fits. However, the decay kinetics of both indoxyl sulfate and neopterin standards was well described by bi-exponential decays. Based on the fluorescence emission characteristics and statistical analysis, the fluorophores indoxyl sulfate, neopterin, and riboflavin may be considered as potential biomarkers for cervical cancer diagnosis.

Metagenomic analysis of the stool microbiome in patients receiving allogeneic stem cell transplantation: loss of diversity is associated with use of systemic antibiotics and more pronounced in gastrointestinal graft-versus-host disease.

Next-generation sequencing of the hypervariable V3 region of the 16s rRNA gene isolated from serial stool specimens collected from 31 patients receiving allogeneic stem cell transplantation (SCT) was performed to elucidate variations in the composition of the intestinal microbiome in the course of allogeneic SCT. Metagenomic analysis was complemented by strain-specific enterococcal PCR and indirect assessment of bacterial load by liquid chromatography-tandem mass spectrometry of urinary indoxyl sulfate. At the time of admission, patients showed a predominance of commensal bacteria. After transplantation, a relative shift toward enterococci was observed, which was more pronounced under antibiotic prophylaxis and treatment of neutropenic infections. The shift was particularly prominent in patients that developed subsequently or suffered from active gastrointestinal (GI) graft-versus-host disease (GVHD). The mean proportion of enterococci in post-transplant stool specimens was 21% in patients who did not develop GI GVHD as compared with 46% in those that subsequently developed GI GVHD and 74% at the time of active GVHD. Enterococcal PCR confirmed predominance of Enterococcus faecium or both E. faecium and Enterococcus faecalis in these specimens. As a consequence of the loss of bacterial diversity, mean urinary indoxyl sulfate levels dropped from 42.5 ± 11 µmol/L to 11.8 ± 2.8 µmol/L in all post-transplant samples and to 3.5 ± 3 µmol/L in samples from patients with active GVHD. Our study reveals major microbiome shifts in the course of allogeneic SCT that occur in the period of antibiotic treatment but are more prominent in association with GI GVHD. Our data indicate early microbiome shifts and a loss of diversity of the intestinal microbiome that may affect intestinal inflammation in the setting of allogeneic SCT.

The uremic toxin indoxyl sulphate enhances macrophage response to LPS.

Indoxyl sulphate (IS) is a protein-bound uremic toxin that results from the metabolism of dietary tryptophan normally excreted by kidney through the proximal tubules. Thus the toxin accumulates in the blood of patients with impaired renal function such as in chronic kidney disease (CKD). High IS serum levels in patients with CKD suggest its involvement in CKD progression and in the onset of complications. Its presence in plasma is also a powerful predictor of overall and cardiovascular morbidity/mortality. IS is a well known nephrovascular toxin but very little is known regarding its effects on the immune system and in particular during inflammation. In this study we examined the effect of IS on macrophage activation in response to lipopolysaccharide from E. coli (LPS), a gram negative bacterial endotoxin associated with inflammation and septic shock. To simulate the uremic condition, J774A.1 macrophages were incubated with IS at concentrations observed in uremic patients (1000-62.5 µM) both alone and during LPS challenge. IS alone induced release of reactive oxygen species (ROS), through a mechanism involving pro- and anti-oxidant systems, and alteration in intracellular calcium homeostasis. When added to J774A.1 macrophages in presence of LPS, IS significantly increased the nitric oxide (NO) release, inducible nitric oxide synthase (iNOS) and cycloxygenase-2 (COX-2) expression. IS pre-treatment was also associated with an increase in tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6) production by macrophages stimulated with LPS. Mechanistic studies revealed that IS increased LPS-induced NF-kB nuclear translocation, ROS release and altered calcium concentrations, mainly because of mitochondrial calcium overloading. Moreover also in primary mouse peritoneal macrophages IS enhances the inflammatory response to LPS increasing ROS, NO, iNOS, COX-2, TNF-α, IL-6 and NF-kB levels. This study provides evidences that IS stimulates macrophage function and enhances inflammatory reasponse associated with LPS, thus contributing to altered immune response dysfunctions observed in CKD.

Toxicometabolomics of urinary biomarkers for human gastric cancer in a mouse model.

Toxicometabolomics of urinary biomarkers for human gastric cancer in a mouse model was investigated using (1)H-nuclear magnetic resonance (NMR) spectroscopy. A human gastric adenocarcinoma cell line (1 × 10(7) cells/ml) was grafted onto the skin of the back of intact male BALB/c-nu/nu mice. After the xenografted tumors developed, urine was collected and analyzed for endogenous metabolites. Global profiling combined with principal components analysis (PCA), partial least squares-discriminant analysis (PLS-DA), and orthogonal projections to latent squares-discriminant analysis (OPLS-DA) showed distinct separation of clusters between control and tumor-bearing mice. Targeted profiling revealed significant changes in trimethylamine oxide (TMAO), 3-indoxylsulfate, hippurate, and citrate levels in mice carrying human gastric cancer cells compared to normal mice. The levels of TMAO (0.41-fold) and hippurate (0.26-fold) in tumor-bearing mice were significantly decreased, whereas the levels of 3-indoxylsulfate (3.39-fold), 2-oxoglutarate (2.32-fold), and citrate (1.9-fold) were significantly increased in urine samples of tumor-bearing mice. Data suggest that TMAO, hippurate, 3-indoxylsulfate, 2-oxoglutarate, and citrate may serve as useful urinary biomarkers for gastric tumorigenesis in a mouse model.

Case analysis of purple urine-bag syndrome at a long-term care service in a community hospital.

BACKGROUND: Purple urine-bag syndrome (PUBS) is a rare phenomenon in which the contents of urine bags turn purple or blue following patient catheterization. The condition often causes care givers tremendous distress. We investigated the prevalence and possible causes of PUBS for a group of elderly patients. METHODS: A total of 157 patients featuring urine catheterization, 13 of whom exhibiting PUBS were analyzed with regards to age, functional status, duration of catheterization, number of daily medications, living location, feeding route, bowel habits, and the pattern of use of a urinary catheter. Urine samples were cultured from all the PUBS patients participating. RESULTS: Two men who underwent cystostomy and 11 women who underwent urethral catheterization who exhibited PUBS were observed for this study. The age, duration of catheterization, number of daily medications feeding pattern and functional status between the group exhibiting PUBS and the group of patients without PUBS demonstrated no significant differences. A total of 69.2% of the PUBS-affected patients, as compared to 43.1% of the non-PUBS patients, lived in nursing homes, and 84.6% of the PUBS-affected patients were constipated, as were 66% of the non-PUBD subjects. In total, 72.7% of PUBS patients were reported to be using a laxative suppository, compared with 41% of the non-PUBS group, whereas 92.3% of PUBS patients were catheterized using a plastic (PVC) foley, as compared to 70.8% of the non-PUBS patients. The pH for 12 out of 13 PUBS patients' urine was > or = 7. Escherichia coli, Provendicia var. spp., Proteus mirabilis, Klebsiella pneumoniae were the common pathogens isolated from the urine samples provided by our PUBS patients. CONCLUSION: We found that PUBS was more likely associated with the female gender, alkaline urine, constipation, institutionalization, the use of a plastic (PVC) urinary catheter, and certain bacteria such as Provendicia var. spp., Escherichia coli, Proteus mirabilis, and Klebsiella pneumoniae.

Sir William Osler's perceptions of urolithiasis and the case of the indigo calculus.

BACKGROUND: Sir William Osler published his textbook, The Principles and Practice of Medicine, in 1892. It became the definitive treatise on a wide variety of diseases. The section on nephrolithiasis clearly presents the etiology, pathology, symptoms, diagnosis, and treatments. What remains a mystery is the mention, under rare forms of human stones, of a type called "indigo." MATERIALS AND METHODS: A search of Index Medicus starting from 1909 backward to its inception in 1879 was performed for key words "indigo," "calculus," "renal" or "bladder stones" and "indicanuria." Twelve textbooks of urology published before 1940 were scrutinized for references to indigo calculi. RESULTS: Only two references to indigo were found, both related to its use for treating constipation (1887 and 1891). Of the 12 textbooks, only 4 make passing reference to "indigo stones." They all mention that such calculi are very rare, but direct references to cases are lacking. One textbook references a study of blue stones from Egyptian mummies. CONCLUSION: It is unlikely that Osler's reference to an indigo calculus was taken lightly during his writing of The Principles and Practice of Medicine. The case of the indigo calculus is fascinating and perhaps enlightening if only for the source of Osler's intrigue.