Circulating acetylated polyamines correlate with Covid-19 severity in cancer patients.

Cancer patients are particularly susceptible to the development of severe Covid-19, prompting us to investigate the serum metabolome of 204 cancer patients enrolled in the ONCOVID trial. We previously described that the immunosuppressive tryptophan/kynurenine metabolite anthranilic acid correlates with poor prognosis in non-cancer patients. In cancer patients, we observed an elevation of anthranilic acid at baseline (without Covid-19 diagnosis) and no further increase with mild or severe Covid-19. We found that, in cancer patients, Covid-19 severity was associated with the depletion of two bacterial metabolites, indole-3-proprionate and 3-phenylproprionate, that both positively correlated with the levels of several inflammatory cytokines. Most importantly, we observed that the levels of acetylated polyamines (in particular N1-acetylspermidine, N1,N8-diacetylspermidine and N1,N12-diacetylspermine), alone or in aggregate, were elevated in severe Covid-19 cancer patients requiring hospitalization as compared to uninfected cancer patients or cancer patients with mild Covid-19. N1-acetylspermidine and N1,N8-diacetylspermidine were also increased in patients exhibiting prolonged viral shedding (>40 days). An abundant literature indicates that such acetylated polyamines increase in the serum from patients with cancer, cardiovascular disease or neurodegeneration, associated with poor prognosis. Our present work supports the contention that acetylated polyamines are associated with severe Covid-19, both in the general population and in patients with malignant disease. Severe Covid-19 is characterized by a specific metabolomic signature suggestive of the overactivation of spermine/spermidine N1-acetyl transferase-1 (SAT1), which catalyzes the first step of polyamine catabolism.

UPLC-Q-TOF/MS-based plasma metabolome to identify biomarkers and time of injury in traumatic brain injured rats.

BACKGROUND: To identify the potent metabolic biomarkers and time of injury of traumatic brain injured (TBI). METHODS: A total of 70 Sprague-Dawley rats were used to establish the TBI model in this study. The serum was collected at 3 h, 6 h, 12 h, 24 h, 3 days and 7 days after surgery. Ultra-performance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry was performed to analyze metabolic changes in the serum of the TBI rats from different groups. The differences between the metabolic profiles of the rats in seven groups were analyzed using partial least squares discriminant analysis. RESULTS: Metabolic profiling revealed significant differences between the sham-operated and other groups. A total of 49 potential TBI metabolite biomarkers were identified between the sham-operated group and the model groups at different time points. Among them, six metabolites (methionine sulfone, kynurenine, 3-hydroxyanthranilic acid, 3-Indolepropionic acid, citric acid and glycocholic acid) were identified as biomarkers of TBI to estimate the injury time. CONCLUSION: Using metabolomic analysis, we identified new TBI serum biomarkers for accurate detection and determination of the timing of TBI injury.

Two rapid, accurate liquid chromatography tandem mass spectrometry methods for the quantification of seven uremic toxins: An application for describing their accumulation kinetic profile in a context of acute kidney injury.

Acute kidney injury (AKI) is a frequent, serious complication in critically ill patients. Even if renal replacement therapy is rapidly initiated, AKI may lead to the acute accumulation of metabolic waste products called uremic toxins (UTs). Although the accumulation and effects of UTs have been extensively described in the setting of chronic kidney disease (CKD), few data are available for AKI. A rapid, sensitive, specific method with simple sample preparation is required to facilitate routine blood monitoring of UTs in a context of acute accumulation. We have developed and validated two fast liquid chromatography tandem mass spectrometry methods for the quantification of seven UTs in human serum. The first method (in negative ionization mode) enables the quantification of five UTs (hippuric acid (HA), indoxyl sulfate (IxS), para-cresyl sulfate (pCS), para-cresyl glucuronide (pCG), 3-carboxy-4-methyl-5-propyl-2-furanpropionate (CMPF)). The second method (in positive ionization mode) enables the quantification of two UTs (indole-3-acetic acid (IAA), and trimethylamine N-oxide (TMAO)). Sample preparation consisted of the deproteinization of a small volume of serum (50 µL). The run-times required to assay all the UTs in negative and positive ionization modes were only 2.5 and 2 min, respectively. In order to obtain a reliable, toxin-free matrix for the preparation of calibration standards and quality controls, serum was pretreated with activated charcoal. We used these methods to determine the time course of UT accumulation in eight patients who developed an AKI after cardiac surgery. The calibration curves ranged from 0.1 to 100 µg mL-1 for all the UTs (except for IAA: 0.5 to 100 µg mL-1), and the correlation coefficients were above 0.999 for all. The methods were reproducible, repeatable, and accurate, with all coefficients of variation and biases below 15%. The highest concentrations measured in patients with AKI were lower than those reported in CKD stages 4 and 5 but higher than those observed in patients with no impairment of renal function (particularly for IxS and pCS). Our results also highlighted low accumulation of the other toxins (IAA, HA, TMAO, pCG, and CMPF). The UT concentrations did not rise earlier than that of creatinine; although the return to baseline took longer than for creatinine for some compounds. Lastly, assessment of the time course of UT accumulation as a prognostic marker for AKI (particularly for pCS and IxS) appears to be promising and should be continued in a larger number of patients.

The microbe-derived short-chain fatty acids butyrate and propionate are associated with protection from chronic GVHD.

Studies of the relationship between the gastrointestinal microbiota and outcomes in allogeneic hematopoietic stem cell transplantation (allo-HCT) have thus far largely focused on early complications, predominantly infection and acute graft-versus-host disease (GVHD). We examined the potential relationship of the microbiome with chronic GVHD (cGVHD) by analyzing stool and plasma samples collected late after allo-HCT using a case-control study design. We found lower circulating concentrations of the microbe-derived short-chain fatty acids (SCFAs) propionate and butyrate in day 100 plasma samples from patients who developed cGVHD, compared with those who remained free of this complication, in the initial case-control cohort of transplant patients and in a further cross-sectional cohort from an independent transplant center. An additional cross-sectional patient cohort from a third transplant center was analyzed; however, serum (rather than plasma) was available, and the differences in SCFAs observed in the plasma samples were not recapitulated. In sum, our findings from the primary case-control cohort and 1 of 2 cross-sectional cohorts explored suggest that the gastrointestinal microbiome may exert immunomodulatory effects in allo-HCT patients at least in part due to control of systemic concentrations of microbe-derived SCFAs.

Systemic short chain fatty acids limit antitumor effect of CTLA-4 blockade in hosts with cancer.

Gut microbiota composition influences the clinical benefit of immune checkpoints in patients with advanced cancer but mechanisms underlying this relationship remain unclear. Molecular mechanism whereby gut microbiota influences immune responses is mainly assigned to gut microbial metabolites. Short-chain fatty acids (SCFA) are produced in large amounts in the colon through bacterial fermentation of dietary fiber. We evaluate in mice and in patients treated with anti-CTLA-4 blocking mAbs whether SCFA levels is related to clinical outcome. High blood butyrate and propionate levels are associated with resistance to CTLA-4 blockade and higher proportion of Treg cells. In mice, butyrate restrains anti-CTLA-4-induced up-regulation of CD80/CD86 on dendritic cells and ICOS on T cells, accumulation of tumor-specific T cells and memory T cells. In patients, high blood butyrate levels moderate ipilimumab-induced accumulation of memory and ICOS + CD4 + T cells and IL-2 impregnation. Altogether, these results suggest that SCFA limits anti-CTLA-4 activity.

Identification of metabolite biomarkers in serum of rats exposed to chlorpyrifos and cadmium.

Chlorpyrifos (CPF) and cadmium (Cd) are widespread environmental pollutants, which are often present in drinking water and foods. However, the combined effects of CPF and Cd were not entirely clear at present. There was also no biomarker available to diagnose the poisoning of the two chemicals at low dose for long-term exposures. In this study, we investigated the change of serum metabolites of rats with subchronic exposure to CPF, Cd, and CPF plus Cd using gas chromatography-mass spectrometer-based metabolomics approach. We performed a stepwise optimization algorithm based on receiver operating characteristic to identify serum metabolite biomarkers for toxic diagnosis of the chemicals at different doses after 90-day exposure. We found that aminomalonic acid was the biomarker for the toxicity of Cd alone administration, and serine and propanoic acid were unique biomarkers for the toxicities of CPF plus Cd administrations. Our results suggest that subchronic exposure to CPF and Cd alone, or in combination at their low doses, could cause disturbance of energy and amino acid metabolism. Overall, we have shown that analysis of serum metabolomics can make exceptional contributions to the understanding of the toxic effects following long-term low-dose exposure of the organophosphorus pesticide and heavy metal.

Simultaneous quantification of coproporphyrin-I and 3-carboxy-4-methyl-5-propyl-2-furanpropanoic acid in human plasma using ultra-high performance liquid chromatography coupled to tandem mass spectrometry.

In chronic kidney disease (CKD), organic anion transporting polypeptide (OATP)1B activity is reduced by mechanisms involving 3-carboxy-4-methyl-5-propyl-2-furanpropanoic acid (CMPF), a uremic toxin. Coproporphyrin-I (CP-I) is a sensitive and specific endogenous probe for phenotyping OATP1B activity and a potentially useful tool to individualize the dosage of OATP1B substrates. In this study, we developed and validated an assay for simultaneous quantification of CP-I and CMPF in human plasma using ultra-high performance liquid chromatography with tandem mass spectrometry (UHPLC-MS/MS). The samples were prepared by solid phase extraction, and then subjected to UHPLC-MS/MS quantification. The assay fulfilled the requirements of the US Food and Drug Administration (FDA) guideline for assay validation, with a lower limit of quantification of 0.1 for CP-I and 50 ng/mL for CMPF. Recovery rates from human plasma ranged from 97.3%-109.8% for CP-I, and 94.1%-113.3% for CMPF. Matrix effects corrected by internal standards varied between 107.2 % and 119.3 % for CP-I, and between 90.4 % and 107.4 % for CMPF. The validated assay was applied to measurement of plasma CP-I and CMPF concentrations in 10 healthy volunteers, 14 stage 3-5 CKD patients, and 14 stage 5D CKD patients. The concentrations measured in all samples were within the calibration ranges. Our novel method may be clinically useful for simultaneous measurement of plasma CP-I and CMPF concentrations in human samples, and contribute to reveal the in vivo relationship of OATB1B activity with accumulation of CMPF in CKD patients.

Changes in Plasma Short-Chain Fatty Acid Levels after Dietary Weight Loss Among Overweight and Obese Adults over 50 Weeks.

Gut microbial-derived short-chain fatty acids (SCFAs) may regulate energy homeostasis and exert anti-carcinogenic, immunomodulatory and anti-inflammatory effects. Smaller trials indicate that dietary weight loss may lead to decreased SCFA production, but findings have been inconclusive. SCFA concentrations were measured by HPLC-MS/MS in plasma samples of 150 overweight or obese adults in a trial initially designed to evaluate the metabolic effects of intermittent (ICR) versus continuous (CCR) calorie restriction (NCT02449148). For the present post hoc analyses, participants were classified by quartiles of weight loss, irrespective of the dietary intervention. Linear mixed models were used to analyze weight-loss-induced changes in SCFA concentrations after 12, 24 and 50 weeks. There were no differential changes in SCFA levels across the initial study arms (ICR versus CCR versus control) after 12 weeks, but acetate concentrations significantly decreased with overall weight loss (mean log-relative change of -0.7 ± 1.8 in the lowest quartile versus. -7.6 ± 2 in the highest, p = 0.026). Concentrations of propionate, butyrate and other SCFAs did not change throughout the study. Our results show that weight-loss, achieved through calorie restriction, may lead to smaller initial decreases in plasma acetate, while plasma SCFAs generally remain remarkably stable over time.

Assessment of methylcitrate and methylcitrate to citrate ratio in dried blood spots as biomarkers for inborn errors of propionate metabolism.

Deficiency of propionyl-CoA carboxylase causes propionic acidemia and deficiencies of methylmalonyl-CoA mutase or its cofactor adenosylcobalamin cause methylmalonic acidemia. These inherited disorders lead to pathological accumulation of propionyl-CoA which is converted in Krebs cycle to methylcitrate (MCA) in a reaction catalyzed by citrate synthase. In healthy individuals where no propionyl-CoA accumulation occurs, this enzyme drives the condensation of acetyl-CoA with oxaloacetate to produce citric acid (CA), a normal Krebs cycle intermediate. The competitive synthesis of CA and MCA through the same enzymatic mechanism implies that increase in MCA production is accompanied by decrease in CA levels. In this study, we assessed MCA concentration and the ratio of MCA/CA as plausible markers for propionic and methylmalonic acidemias. We measured MCA and CA in dried blood spots using liquid chromatography tandem mass spectrometry. The reference ranges of MCA, CA and MCA/CA in 123 healthy individuals were ≤0.63 µmol/L, 36.6-126.4 µmol/L and 0.0019-0.0074, respectively. In patients with propionic and methylmalnic acidemias (n = 7), MCA concentration ranged between 1.0-12.0 µmol/L whereas MCA/CA was between 0.012-0.279. This is the first report to describe the potential role of MCA and MCA/CA in dried blood spots as diagnostic and monitoring biomarkers for inherited disorders of propionyl-CoA metabolism.

Plasma alkylresorcinol metabolite, a biomarker of whole-grain wheat and rye intake, and risk of ischemic stroke: a case-control study.

Background: Epidemiologic studies on whole grains and risk of stroke have reported inconsistent results, with some suggesting a protective effect but others showing a null association. Objectives: The aim of this study was to examine whether plasma 3-(3,5-dihydroxyphenyl)-1-propanoic acid (DHPPA), a biomarker of whole-grain wheat and rye intake, is associated with risk of ischemic stroke. Methods: A hospital-based case-control study was conducted between March 2011 and May 2016. Cases (n = 990) with first ischemic stroke were matched to controls (n = 990) by sex and age. Concentrations of plasma DHPPA were determined by high-performance liquid chromatography-tandem mass spectrometry. We calculated ORs for the association of plasma DHPPA concentrations with ischemic stroke risk through the use of logistic regression. Results: Plasma DHPPA was inversely associated with ischemic stroke risk. After adjustment for potential confounding factors, the ORs for ischemic stroke across increasing quartiles of plasma DHPPA concentrations were 1 (referent), 0.76 (95% CI: 0.58, 0.99), 0.71 (95% CI: 0.54, 0.92), and 0.59 (95% CI: 0.45, 0.77), respectively (P-trend = 0.001). The inverse association was also observed in all subgroups of participants according to sex, age, body mass index, smoking status, alcohol consumption, history of hypertension, and history of diabetes. Conclusions: Our study showed that higher plasma DHPPA concentrations were associated with lower risk of ischemic stroke. This finding provides further evidence to support the health benefits of whole-grain consumption.

Simple and rapid determination of zaltoprofen in human plasma by manual-shaking-assisted dispersive liquid-liquid microextraction followed by liquid chromatography with ultraviolet detection.

A readily applicable method was developed to determine the concentration level of zaltoprofen, a non-steroidal antiinflammatory drug from the propionic acid family, in human plasma. This method is based on manual-shaking-assisted dispersive liquid-liquid microextraction coupled with liquid chromatography with ultraviolet detection. Factors affecting the extraction efficiency were screened and optimized by experimental design using fractional factorial and central composite designs, respectively. Optimal conditions were: 220 µL of C2 H4 Cl2 (extraction solvent), 5 mL of 3.75% w/v NaCl aqueous solution at pH 2.0, and manual shaking for 13 s (65 times). The resulting extraction method yielded a reasonable enrichment factor of 18.0 (±0.6, n = 3) and extraction recovery of 86.0% (±3.3%, n = 3). The established method was validated for selectivity, linearity, precision, accuracy, matrix effect, recovery, dilution integrity, and stability, and it met the acceptable criteria for all of the tested parameters. Specifically, the method was linear in the range of 0.16-50.0 mg/L, precise (< 8.8% RSD), accurate (-7.5-5.6% deviation), and showed negligible matrix effects (96.1-106.4%) with high absolute recovery (94.5-97.7%). Compared with previous methods involving labor-intensive liquid-liquid extraction or non-specific protein precipitation, our method allows the simple, rapid, and efficient determination of zaltoprofen using the most affordable analytical instrument, liquid chromatography with ultraviolet detection.

Plasma phospholipase, γ-CEHC and antioxidant capacity in fibromyalgia.

OBJECTIVE: Recent studies have suggested a possible role of high levels of plasma lysophosphocholines (lysoPCs) in fibromyalgia syndrome (FMS). The aim of this study was to evaluate the content of plasma phospholipases (e.g., Platelet Activating Factor Acetyl Hydrolase [PAF-AH], secretory Phospholipase A2 [sPLA2 ], Total Antioxidant Capacity [TAOC] and 2,7,8-trimethyl-2-(2-carboxyethyl)-6-hydroxy chroman [γ-CEHC]) in FMS patients and their association with clinical status and quality of life. METHODS: Thirty-six females meeting the 2011 American College of Rheumatology criteria for the classification of FMS and thirty-four healthy females were enrolled for the study. Plasma enzyme levels were quantified using commercial enzyme-linked-immunosorbent-assay (ELISA). In order to assess the disease severity and the functional status of patients, the Fibromyalgia Impact Questionnarie (FIQ) was used. RESULTS: Higher levels of sPLA2 and lower PAF-AH and γ-CEHC were observed in the plasma of FMS patients compared to the controls. A decrease in PAF-AH and TAOC levels were found in severe FMS (S-FMS) compared to mild/slight (MS-FMS) forms. CONCLUSION: The results of the study indicate a possible involvement of phospholipases and γ-CEHC in fibromyalgia syndrome.

Metabolomics analysis of serum 25-hydroxy-vitamin D in the Alpha-Tocopherol, Beta-Carotene Cancer Prevention (ATBC) Study.

BACKGROUND: Vitamin D has been discussed in the context of cardiovascular disease, cancer, bone health and other outcomes. Epidemiological studies have reported on the importance of vitamin D in cancer prevention and treatment. The discovery of vitamin D-associated metabolites through agnostic metabolomics analyses offers a new approach for elucidating disease aetiology and health-related pathway identification. METHODS: Baseline serum 25-hydroxy-vitamin D [25(OH)D] and 940 serum metabolites were measured in 392 men from eight nested cancer case-control studies in the Alpha-Tocopherol, Beta-Carotene Cancer Prevention Study of Finnish male smokers (aged 50-69 years). The metabolomic profiling was conducted using mass spectrometry. We used linear regression to estimate the standardized beta-coefficient as the effect metric for the associations between metabolites and 25(OH)D levels. RESULTS: A majority of the metabolites associated with 25(OH)D were of lipid origin, including 3-carboxy-4-methyl-5-propyl-2-furanpropanoic acid (CMPF) [beta-estimate 0.38 per 1 standard deviation (SD) increment], stearoyl-arachidonoyl-glycerophosphoethanolamine (GPPE) (-0.38 per SD) and two essential fatty acids: eicosapentaenoate (EPA; 0.17 per SD) and docosahexaenoate (DHA; 0.13 per SD). Each of these lipid metabolites was associated with 25(OH)D at the principal components corrected P-value of 3.09 × 10-4 CONCLUSIONS: The large number of metabolites, particularly lipid compounds, found to be associated with serum 25(OH)D provide new biological clues relevant to the role of vitamin D status and human health outcomes. The present findings should be re-examined in other metabolomics studies of diverse populations.

An accessible pharmacodynamic transcriptional biomarker for notch target engagement.

γ-Secretase mediates amyloid production in Alzheimer's disease (AD) and oncogenic activity of Notch. γ-Secretase inhibitors (GSIs) are thus of interest for AD and oncology. A peripheral biomarker of Notch activity would aid determination of the therapeutic window and dosing regimen for GSIs, given toxicities associated with chronic Notch inhibition. This study examined the effects of GSI MK-0752 on blood and hair follicle transcriptomes in healthy volunteers. The effects of a structurally diverse GSI on rhesus blood and hair follicles were also compared. Significant dose-related effects of MK-0752 on transcription were observed in hair follicles, but not blood. The GSI biomarker identified in follicles exhibited 100% accuracy in a clinical test cohort, and was regulated in rhesus by a structurally diverse GSI. This study identified a translatable, accessible pharmacodynamic biomarker of GSI target engagement and provides proof of concept of hair follicle RNA as a translatable biomarker source.

Biodistribution and Pharmacokinetic Study of 3,3' Diseleno Dipropionic Acid (DSePA), A Synthetic Radioprotector, in Mice.

BACKGROUND AND OBJECTIVES: 3,3' Diseleno dipropionic acid (DSePA), a synthetic compound has been shown to have radioprotective activity, especially as a lung radioprotector. In this study, the pharmacokinetics and biodistribution of DSePA in MX-1 tumour bearing SCID mice were evaluated. METHODS: Twenty SCID mice were administered DSePA (50 mg/kg bodyweight) by oral gavage following which four animals each were sacrificed at 15, 30 min, 1, 2 and 4 h. Blood and tissue samples were collected for determination of DSePA concentration by graphite furnace atomic absorption spectrometry (GFAAS) method. The control group (n = 4) was administered sterile water and sacrificed at 4 h. RESULTS: Peak plasma concentration (C max) of 2.7 µg/ml was observed at 15 min which returned to near baseline (baseline = 0.6 µg/ml) at 1 h following drug administration. Biphasic pharmacokinetics characterized by rapid distribution phase and a slower elimination phase were observed. Highest maximal concentration (C max) of the drug was observed in lung (19.2 µg/g at 30 min) followed by intestine (14.64 µg/g at 15 min) and kidney (12.96 µg/g at 15 min). There was negligible uptake in tumor tissue and no uptake in brain. CONCLUSIONS: DSePA has a favorable pharmacokinetic profile which makes it a potentially good candidate for further development as a radioprotective agent.

Effects of whole-grain cereal foods on plasma short chain fatty acid concentrations in individuals with the metabolic syndrome.

OBJECTIVE: Short chain fatty acids (SCFAs) derived from dietary fiber fermentation by gut microbiota have been identified as one of the mechanisms behind the association between habitual whole-grain intake and a lower risk of cardiometabolic diseases. The aims of the present work are: (1) to evaluate whether a whole-grain wheat-based diet may increase SCFAs concentration, and (2) to identify possible associations between SCFAs and metabolic changes observed after the nutritional intervention. METHODS: Fifty-four subjects participated in the trial. They underwent a 12-wk dietary intervention based on whole-grain or refined cereal products. At baseline and after the intervention, glucose, insulin, triacylglycerol, inflammatory markers (hs-CRP, IL-1 ra, IL-6, and TNF-α), and SCFAs plasma concentrations were evaluated. RESULTS: After the intervention, in the whole-grain group fasting plasma propionate concentrations were higher than at baseline, whereas a reduction was detected in the control group. The absolute changes (end of trial minus baseline) in fasting plasma propionate concentrations were significantly different between the two groups (P = 0.048). The absolute changes of fasting propionate correlated with cereal fiber intake (r = 0.358, P = 0.023), but no significant correlations with clinical outcomes were found. However, postprandial insulin was significantly decreased in the group having the absolute changes of fasting propionate concentration above the median value (P = 0.022 versus subjects with fasting propionate changes below the median value). CONCLUSIONS: A 12-wk whole-grain wheat-based diet increases fasting plasma propionate. This increase correlates with the cereal fiber intake and is associated with lower postprandial insulin concentrations.

Phase I trial of weekly MK-0752 in children with refractory central nervous system malignancies: a pediatric brain tumor consortium study.

PURPOSE: Amplification and high levels of NOTCH ligand expression have been identified in several types of pediatric brain tumors. A phase I trial of weekly MK-0752, an oral inhibitor of gamma-secretase, was conducted in children with recurrent central nervous system (CNS) malignancies to estimate the maximum tolerated dose, dose-limiting toxicities (DLT), pharmacokinetics (PK), and pharmacodynamics of weekly MK-0752. METHODS: MK-0752 was administered once weekly at 1000 and 1400 mg/m(2) using a rolling-6 design. PK analysis was performed during the first course. NOTCH and HES expression was assessed by immunohistochemistry and Western blot. RESULTS: Ten eligible patients were enrolled (median age 8.8 years; range 3.1-19.2) with diagnoses of brain stem glioma (n = 3), ependymoma (n = 2), anaplastic astrocytoma (n = 1), choroid plexus carcinoma (n = 2), medulloblastoma (n = 1), and primitive neuroectodermal tumor (n = 1). Nine were evaluable for toxicity. One DLT of fatigue occurred in the six evaluable patients enrolled at 1000 mg/m(2)/dose. No DLTs were experienced by three patients treated at 1400 mg/m(2)/dose. Non-dose-limiting grade 3 toxicities included lymphopenia, neutropenia, and anemia. Median number of treatment courses was 2 (range 1-10). Two patients continued on therapy for at least 6 months. The median (range) C(max) of MK-0752 was 88.2 µg/mL (40.6 to 109 µg/mL) and 60.3 µg/mL (59.2 to 91.9 µg/mL) in patients receiving 1000 and 1400 mg/m(2)/week, respectively. NOTCH expression was decreased in six of seven patients for whom tissue was available at 24 h post-MK-0752. CONCLUSION: MK-0752 is well tolerated and exhibits target inhibition at 1000 and 1400 mg/m(2)/week in children with recurrent CNS malignancies.

The furan fatty acid metabolite CMPF is elevated in diabetes and induces ß cell dysfunction.

Gestational diabetes (GDM) results from failure of the ß cells to adapt to increased metabolic demands; however, the cause of GDM and the extremely high rate of progression to type 2 diabetes (T2D) remains unknown. Using metabolomics, we show that the furan fatty acid metabolite 3-carboxy-4-methyl-5-propyl-2-furanpropanoic acid (CMPF) is elevated in the plasma of humans with GDM, as well as impaired glucose-tolerant and T2D patients. In mice, diabetic levels of plasma CMPF induced glucose intolerance, impaired glucose-stimulated insulin secretion, and decreased glucose utilization. Mechanistically, we show that CMPF acts directly on the ß cell, causing impaired mitochondrial function, decreasing glucose-induced ATP accumulation, and inducing oxidative stress, resulting in dysregulation of key transcription factors and ultimately reduced insulin biosynthesis. Importantly, specifically blocking its transport through OAT3 or antioxidant treatment could prevent CMPF-induced ß cell dysfunction. Thus, CMPF provides a link between ß cell dysfunction and GDM/T2D that could be targeted therapeutically.

Effects of decreased vitamin D and accumulated uremic toxin on human CYP3A4 activity in patients with end-stage renal disease.

In patients with end-stage renal disease, not only renal clearance but also hepatic clearance is known to be impaired. For instance, the concentration of erythromycin, a substrate of cytochrome P450 3A4 (CYP3A4), has been reported to be elevated in patients with end-stage renal disease. The purpose of this study is to elucidate the reason for the decrease in hepatic clearance in patients with end-stage renal disease. Deproteinized pooled sera were used to assess the effects of low-molecular-weight uremic toxins on CYP3A4 activity in human liver microsomes and human LS180 cells. Four uremic toxins (3-carboxy-4-methyl-5-propyl-2-furanpropanoic acid, hippuric acid, indole-3-acetic acid, and 3-indoxyl sulfate) present at high concentrations in uremic serum were also studied. Simultaneous treatment of uremic serum (less than 10%) or uremic toxins did not affect testosterone 6ß-hydroxylation in human liver microsomes. On the other hand, pretreatment of each serum activates CYP3A4 in LS180 cells, and the increased CYP3A4 activity in uremic serum-treated cells was smaller than normal serum-treated cells. In addition, CYP3A4 and CYP24A1 mRNA levels also increased in LS180 cells exposed to normal serum, and this effect was reduced in uremic serum-treated cells and in cells exposed to uremic serum added to normal serum. Furthermore, addition of 1,25-dihydroxyvitamin D to uremic serum partially restored the serum effect on CYP3A4 expression. The present study suggests that the decrease of 1,25-dihydroxyvitamin D and the accumulation of uremic toxins contributed to the decreased hepatic clearance of CYP3A4 substrates in patients with end-stage renal disease.

The effect of genetic polymorphisms in UGT2B15 on the pharmacokinetic profile of sipoglitazar, a novel anti-diabetic agent.

PURPOSE: Sipoglitazar was a novel, azolealkanoic acid derivative that possesses selective activity for the peroxisome proliferator-activated receptors (PPAR) PPARγ, PPARα, and PPARδ. The compound undergoes phase II biotransformation by conjugation catalyzed by UDP-glucuronosyltransferase (UGT). The aim of this analysis was to explore the influence of genetic polymorphism in UGT on the pharmacokinetics of sipoglitazar. METHODS: Three preliminary phase I clinical pharmacology studies were conducted in tandem in healthy human subjects. Genotyping was undertaken in a total of 82 subjects in the phase I program for the purpose of genotyping UGT polymorphisms. Plasma samples were collected for up to 48 h post-dose to characterize the pharmacokinetic profile following a single oral dose of the drug. RESULTS: Plasma concentrations of sipoglitazar and the distribution of dose-normalized individual values for area under the plasma concentration-time curve from time 0 to infinity (AUC(0-∞)) before any stratification were considerably skewed with a multi-modal distribution. The proportion of variability in AUC(0-∞) explained by UGT2B15 was 66.7 % (P < 0.0001); the addition of other genetic or demographic factors was not statistically significant. Subjects homozygous for the UGT2B15 D85Y variant (UGT2B15*2/*2) were exposed to greater plasma concentrations of sipoglitazar than subjects homozygous for the wild-type allele UGT2B15*1/*1 (3.26-fold higher) or heterozygous allele UGT2B15*1/*2 (2.16-fold higher). CONCLUSIONS: These results indicate that sipoglitazar clearance is substantially modified by UGT2B15 enzyme variants, with higher exposure observed in the UGT2B15*2/*2 genotype group.