Methylated Metabolites Research Articles

Inhibitory Effects of Quercetin and Its Main Methyl, Sulfate, and Glucuronic Acid Conjugates on Cytochrome P450 Enzymes, and on OATP, BCRP and MRP2 Transporters.

Quercetin is a flavonoid, its glycosides and aglycone are found in significant amounts in several plants and dietary supplements. Because of the high presystemic biotransformation of quercetin, mainly its conjugates appear in circulation. As has been reported in previous studies, quercetin can interact with several proteins of pharmacokinetic importance. However, the interactions of its metabolites with biotransformation enzymes and drug transporters have barely been examined. In this study, the inhibitory effects of quercetin and its most relevant methyl, sulfate, and glucuronide metabolites were tested on cytochrome P450 (CYP) (2C19, 3A4, and 2D6) enzymes as well as on organic anion-transporting polypeptides (OATPs) (OATP1A2, OATP1B1, OATP1B3, and OATP2B1) and ATP (adenosine triphosphate) Binding Cassette (ABC) (BCRP and MRP2) transporters. Quercetin and its metabolites (quercetin-3′-sulfate, quercetin-3-glucuronide, isorhamnetin, and isorhamnetin-3-glucuronide) showed weak inhibitory effects on CYP2C19 and 3A4, while they did not affect CYP2D6 activity. Some of the flavonoids caused weak inhibition of OATP1A2 and MRP2. However, most of the compounds tested proved to be strong inhibitors of OATP1B1, OATP1B3, OATP2B1, and BCRP. Our data demonstrate that not only quercetin but some of its conjugates, can also interact with CYP enzymes and drug transporters. Therefore, high intake of quercetin may interfere with the pharmacokinetics of drugs.

Natriuretic peptides and echocardiographic parameters in Mexican children environmentally exposed to arsenic

BackgroundArsenic exposure is associated with cardiovascular risk in adults; however, few epidemiologic studies have evaluated biomarkers of cardiovascular risk in children who are environmentally exposed to arsenic. ObjectiveThe aim of this study was to assess the associations between urinary arsenic, plasma natriuretic peptides and echocardiographic parameters in Mexican children exposed to arsenic through the drinking water. MethodsWe conducted a cross-sectional study with 192 children (3–8 years old) from Zimapan, Hidalgo, Mexico. B-type natriuretic peptide (BNP), NT-proBNP and atrial natriuretic peptide (ANP) were measured by ELISA, urinary arsenic concentration (UAs) were measured via by hydride generation-cryotrapping-atomic absorption spectrometry, and cardiac parameters were measured by echocardiography. ResultsThe median plasma concentrations of ANP, BNP and NT-proBNP were 36.9 ng/mL, 49.7 pg/mL, and 226.1 pg/mL, respectively. Using multivariable models, a dose-response relationship was observed between BNP concentrations and UAs tertiles (<47 ng/mL: reference, 47–72 ng/mL: 48.7 pg/mL, >72 ng/mL: 52.2 pg/mL, P-trend = 0.020). BNP concentrations also increased with increasing U-tAs as continuous variables (0.43 pg/mL increase per 1 ng/mL increase of U-tAs; P-Value = 0.008). Additionally, BNP was positively associated with arsenic methylated metabolites (U-MAs and U-DMAs). On the other hand, BNP was inversely related to relative wall thickness (RWT). No associations were found for other cardiac parameters. Finally, neither ANP nor NT-proBNP were significantly related to arsenic exposure or echocardiographic parameters. ConclusionsIn this study, we showed associations between plasma BNP and arsenic exposure. Our results support the importance of reducing childhood arsenic exposure, which may have cardiovascular effects early in life.

Fabrication and characterization of dihydromyricetin encapsulated zein-caseinate nanoparticles and its bioavailability in rat.

Dihydromyricetin (DMY) encapsulated zein-caseinate nanoparticles (DZP) were fabricated by antisolvent method. The encapsulation and loading efficiency of DMY in DZP were 90.2% and 22.6% as determined by HPLC. DZP is spherical with particle size and ζ potential of 206.4nm and -29.6mV, respectively. Physicochemical characterization showed that DMY existed in amorphous form in DZP and its interaction with proteins was found. The fabrication of DZP significantly improved the stability of DMY. Besides, the diffusion rate of DMY in DZP was faster than its suspensions in both simulated gastric and intestinal fluid. The adhesion of DMY in mice gastrointestinal tract was also improved. Besides DMY itself, its methylated metabolites with further sulfation and glucuronide were identified in rat plasma by UPLC-QTOF-MS. UPLC-QqQ-MS/MS quantitative analysis showed that the oral bioavailability of DMY was 1.95 times enhanced. Besides, the concentration of DMY metabolites in plasma were all increased.

The Zebrafish (Danio Rerio) as a Novel Model to Study Folate-mthfr Interactions During Embryonic Development and Effect(s) on Long-Term Health

Abstract Objectives Methylenetetrahydrofolate reductase (MTHFR) catalyzes the synthesis of the bioactive folate form, 5-methyltetrahydrofolate (5MTHF). Common polymorphisms in MTHFR limits the availability of 5MTHF and high intakes of folic acid (FA, synthetic form) may exacerbate these effects. 5MTHF is an alternative supplement to FA, but the interaction of folate form and MTHFR genotype and role in programming metabolic health has not been determined. The zebrafish (Danio rerio) is a proven model system in nutrient and drug discovery studies. The objectives of this study were to: 1) develop a mthfr zebrafish mutant model using CRISPR-Cas9 technology; and 2) identify in zebrafish the relationship between folate form (FA vs 5MTHF) and mthfr genotype on early-life development and metabolic regulation. Methods To assay the function of mthfr in vivo, we used a rapid transient knock-out approach reported to recapitulate germline zebrafish loss-of-function phenotypes. Embryos were co-injected with Cas9 protein and a set of 4 guide RNAs (4gRNA) or Cas9 protein alone (control). Zero to 5 days post-fertilization (dpf), embryos were raised in standard conditions then fed a high cholesterol diet (HCD) up to 15 dpf with a fluorescent cholesteryl BODIPY-C12. The HCD was used to induce obesity as previously reported. Global DNA methylation (5-mC%) was measured at 5 dpf and whole-body and hepatic lipid accumulation and live imaging analyses performed at 15 dpf. Results Compared to control, 4gRNA mthfr zebrafish on an HCD had enlarged liver, greater accumulation of hepatic and whole body lipids and altered lipid transport. They also had 80% lower mthfr mRNA than control zebrafish. Global methylation was ∼15% higher (P = 0.06) in 4gRNA zebrafish suggesting a compensatory dependency on an alternative methyl donor pathway during embryonic development. We are now screening germline mutant carriers and assessing folate and methylation metabolites and the interaction of folate form and genotype. Conclusions The zebrafish mthfr mutant will be a valuable model to examine the mechanisms underlining mthfr-related pathologies and provide a high-throughput in vivo system to ascertain the role of different folate forms on embryonic development and long-term health. Funding Sources CIHR-INMD; EP supported by NSERC-CGS D.

Determination of arsenicals in mouse tissues after simulated exposure to arsenic from rice for sixteen weeks and the effects on histopathological features

The accumulation of arsenic in rice has become a worldwide concern. In this study, dose-dependency in tissues (intestine, liver and kidney) and blood distribution of inorganic arsenicals and their methylated metabolites were investigated in male C57BL/6 mice exposed to four arsenic species (arsenite [iAs]III, arsenate [iAs]V, monomethylarsonate [MMA]V, and dimethylarsinate [DMA]V) at four doses (control [C]: 0μg/g, simulation [S]: 0.91μg/g, medium [M]: 9.1μg/g and high [H]: 30μg/g) according to the arsenical composition in rice for 8 and 16 weeks. No adverse effects were observed, while body weight gain decreased in group H. Increases in total arsenic concentrations (CtAs) and histopathological changes in the tissues occurred in all of the test groups. CtAs presented a tendency of kidney>intestine>liver>blood and were time-/dose-dependent in the liver and kidney in groups M and H. In the intestine and blood, abundant iAs (23%-28% in blood and 36%-49% in intestine) was detected in groups M and H, and CtAs decreased in group H from the 8th week to the 16th week. PMI decreased in the liver and SMI decreased in the kidney. These results indicate that the three tissues are injured through food arsenic. The intestine can also accumulate food arsenic, and the high arsenic dose will cause a deficiency in the absorbing function of the intestine. Thus, long-term exposure to arsenic-contaminated rice should be taken seriously attention.

Review article: opportunities to improve and expand thiopurine therapy for autoimmune hepatitis.

Thiopurines in combination with glucocorticoids are used as first-line, second-line and maintenance therapies in autoimmune hepatitis and opportunities exist to improve and expand their use. To describe the metabolic pathways and key factors implicated in the efficacy and toxicity of the thiopurine drugs and to indicate the opportunities to improve outcomes by monitoring and manipulating metabolic pathways, individualising dosage and strengthening the response. English abstracts were identified in PubMed by multiple search terms. Full-length articles were selected for review, and secondary and tertiary bibliographies were developed. Thiopurine methyltransferase activity and 6-tioguanine (6-thioguanine) nucleotide levels influence drug efficacy and safety, and they can be manipulated to improve treatment response and prevent myelosuppression. Methylated thiopurine metabolites are associated with hepatotoxicity, drug intolerance and nonresponse and their production can be reduced or bypassed. Universal pre-treatment assessment of thiopurine methyltransferase activity and individualisation of dosage to manipulate metabolite thresholds could improve outcomes. Early detection of thiopurine resistance by metabolite testing, accurate estimations of drug onset and strength by surrogate markers and adjunctive use of allopurinol could improve the management of refractory disease. Dose-restricted tioguanine (thioguanine) could expand treatment options by reducing methylated metabolites, increasing the bioavailability of 6-tioguanine nucleotides and ameliorating thiopurine intolerance or resistance. The efficacy and safety of thiopurines in autoimmune hepatitis can be improved by investigational efforts that establish monitoring strategies that allow individualisation of dosage and prediction of outcome, increase bioavailability of the active metabolites and demonstrate superiority to alternative agents.

Possible Adverse Effects of High-Dose Nicotinamide: Mechanisms and Safety Assessment.

Nicotinamide (NAM) at doses far above those recommended for vitamins is suggested to be effective against a wide spectrum of diseases and conditions, including neurological dysfunctions, depression and other psychological disorders, and inflammatory diseases. Recent increases in public awareness on possible pro-longevity effects of nicotinamide adenine dinucleotide (NAD+) precursors have caused further growth of NAM consumption not only for clinical treatments, but also as a dietary supplement, raising concerns on the safety of its long-term use. However, possible adverse effects and their mechanisms are poorly understood. High-level NAM administration can exert negative effects through multiple routes. For example, NAM by itself inhibits poly(ADP-ribose) polymerases (PARPs), which protect genome integrity. Elevation of the NAD+ pool alters cellular energy metabolism. Meanwhile, high-level NAM alters cellular methyl metabolism and affects methylation of DNA and proteins, leading to changes in cellular transcriptome and proteome. Also, methyl metabolites of NAM, namely methylnicotinamide, are predicted to play roles in certain diseases and conditions. In this review, a collective literature search was performed to provide a comprehensive list of possible adverse effects of NAM and to provide understanding of their underlying mechanisms and assessment of the raised safety concerns. Our review assures safety in current usage level of NAM, but also finds potential risks for epigenetic alterations associated with chronic use of NAM at high doses. It also suggests directions of the future studies to ensure safer application of NAM.

Exposure to inorganic arsenic and its methylated metabolites alters metabolomics profiles in INS-1 832/13 insulinoma cells and isolated pancreatic islets.

Inorganic arsenic (iAs) is an environmental diabetogen, but mechanisms underlying its diabetogenic effects are poorly understood. Exposures to arsenite (iAsIII) and its methylated metabolites, methylarsonite (MAsIII) and dimethylarsinite (DMAsIII), have been shown to inhibit glucose-stimulated insulin secretion (GSIS) in pancreatic β-cells and isolated pancreatic islets. GSIS is regulated by complex mechanisms. Increase in ATP production through metabolism of glucose and other substrates is the ultimate trigger for GSIS in β-cells. In the present study, we used metabolomics to identify metabolites and pathways perturbed in cultured INS-1 832/13 rat insulinoma cells and isolated murine pancreatic islets by exposures to iAsIII, MAsIII and DMAsIII. We found that the exposures perturbed multiple metabolites, which were enriched primarily in the pathways of amino acid, carbohydrate, phospholipid and carnitine metabolism. However, the effects of arsenicals in INS-1 832/13 cells differed from those in the islets and were exposure specific with very few overlaps between the three arsenicals. In INS-1 832/13 cells, all three arsenicals decreased succinate, a metabolite of Krebs cycle, which provides substrates for ATP synthesis in mitochondria. Acetylcarnitine was decreased consistently by exposures to arsenicals in both the cells and the islets. Acetylcarnitine is usually found in equilibrium with acetyl-CoA, which is the central metabolite in the catabolism of macronutrients and the key substrate for Krebs cycle. It is also thought to play an antioxidant function in mitochondria. Thus, while each of the three trivalent arsenicals perturbed specific metabolic pathways, which may or may not be associated with GSIS, all three arsenicals appeared to impair mechanisms that support ATP production or antioxidant defense in mitochondria. These results suggest that impaired ATP production and/or mitochondrial dysfunction caused by oxidative stress may be the mechanisms underlying the inhibition of GSIS in β-cells exposed to trivalent arsenicals.

Assessment of human exposure to selected pesticides in Norway by wastewater analysis

Pesticides offer many benefits for humanity and agriculture, but at the same time pose a potential risk to human health because of their widespread use and high biological activity. Human biomonitoring (HBM) studies are the main tool to investigate human exposure to pesticides and other chemicals, but face limitations such as sampling biases, long time to complete and high costs. Wastewater-based epidemiology (WBE) is an alternative approach that is centered on the chemical analysis of biomarkers of (pesticide) exposure in urban wastewater. The present study used WBE to assess human exposure to selected classes of pesticides, triazines, pyrethroids and organophosphates, in Norway. Untreated wastewater samples were collected from four cities, covering approximately 20% of the Norwegian population. The highest population weighted mass loads (mg/day/1000 inhabitants) were for alkyl phosphates and the lowest for triazines. Some differences were observed for the two metabolites, 2-isopropyl-6-methyl-4-pyrimidinol (IMPY) and 3-(2,2-dichlorovinyl)-2,2-dimethyl-(1-cyclopropane) carboxylic acid (DCCA), which were higher in the rural city of Hamar. WBE figures were comparable with HBM findings for the specific metabolite of chlorpyrifos and chlorpyrifos methyl (3,5,6-trichloro-2-pyridinol; TCPY) but were different for the alkyl phosphates. Pyrethroid intake was calculated and was lower than the acceptable daily intake in all the cities, indicating low risk for human health. This is the most extensive WBE study performed to date to assess national human exposure to pesticides. This study demonstrated that WBE has the potential to be a useful complementary biomonitoring tool for assessing population-wide exposure to pesticides, overcoming some of the limitations of HBM.

Testing the Pharmacokinetic Interactions of 24 Colonic Flavonoid Metabolites with Human Serum Albumin and Cytochrome P450 Enzymes.

Flavonoids are abundant polyphenols in nature. They are extensively biotransformed in enterocytes and hepatocytes, where conjugated (methyl, sulfate, and glucuronide) metabolites are formed. However, bacterial microflora in the human intestines also metabolize flavonoids, resulting in the production of smaller phenolic fragments (e.g., hydroxybenzoic, hydroxyacetic and hydroxycinnamic acids, and hydroxybenzenes). Despite the fact that several colonic metabolites appear in the circulation at high concentrations, we have only limited information regarding their pharmacodynamic effects and pharmacokinetic interactions. Therefore, in this in vitro study, we investigated the interactions of 24 microbial flavonoid metabolites with human serum albumin and cytochrome P450 (CYP2C9, 2C19, and 3A4) enzymes. Our results demonstrated that some metabolites (e.g., 2,4-dihydroxyacetophenone, pyrogallol, O-desmethylangolensin, and 2-hydroxy-4-methoxybenzoic acid) form stable complexes with albumin. However, the compounds tested did not considerably displace Site I and II marker drugs from albumin. All CYP isoforms examined were significantly inhibited by O-desmethylangolensin; nevertheless, only its effect on CYP2C9 seems to be relevant. Furthermore, resorcinol and phloroglucinol showed strong inhibitory effects on CYP3A4. Our results demonstrate that, besides flavonoid aglycones and their conjugated derivatives, some colonic metabolites are also able to interact with proteins involved in the pharmacokinetics of drugs.

Biotransformation Changes Bioaccumulation and Toxicity of Diclofenac in Aquatic Organisms.

Biotransformation plays a crucial role in regulating the bioaccumulation potential and toxicity of organic compounds in organisms but is, in general, poorly understood for emerging contaminants. Here, we have used diclofenac as a model compound to study the impact of biotransformation on the bioaccumulation potential and toxicity in two keystone aquatic invertebrates: Gammarus pulex and Hyalella azteca. In both species, diclofenac was transformed into several oxidation products and conjugates, including two novel products, that is, diclofenac taurine conjugate (DCF-M403) and unexpected diclofenac methyl ester (DCF-M310.03). The ratios of biotransformation products to parent compound were 12-17 for DCF-M403 and 0.01-0.7 for DCF-M310.03 after 24 h exposure. Bioconcentration factors (BCFs) of diclofenac were 0.5 and 3.2 L kgww-1 in H. azteca and G. pulex, respectively, whereas BCFs of DCF-M310.03 was 164.5 and 104.7 L kgww-1, respectively, representing a 25- to 110-fold increase. Acute toxicity of DCF-M310.03 was also higher than the parent compound in both species, which correlated well with the increased bioconcentration potential. The LC50 of diclofenac in H. azteca was 216 mg L-1, while that of metabolite DCF-M310.03 was reduced to only 0.53 mg L-1, representing a 430-fold increase in acute toxicity compared to diclofenac. DCF-M403 is less toxic than its parent compound toward H. azteca, which may be linked to its slightly lower hydrophobicity. Furthermore, the transformation of diclofenac to its methyl ester derivative was explored in crude invertebrate extracts spiked with an S-adenosylmethionine cofactor, revealing possible catalysis by an S-adenosylmethionine-dependent carboxylic acid methyltransferase. Methylation of diclofenac was further detected in fish hepatocytes and human urine, indicating a broader relevance. Therefore, potentially methylated metabolites of polar contaminants should be considered for a comprehensive risk assessment in the future.

Studying the metabolism of toxic chemical warfare agent-related phenylarsenic chemicals in vitro in cod liver

Large quantities of chemical warfare agents (CWAs), such as phenylarsenic chemicals, were disposed by sea-dumping after World War II. Nowadays, the release of these toxic chemicals from munitions poses a potential threat to living organisms. This study investigates the fate of these chemicals in fish by exposing selected CWA-related phenylarsenic chemicals and their oxidation products to cod (Gadus morhua) liver S9 fraction in vitro. Clark I (DA), Adamsite (DM) and their corresponding oxidation products as well as triphenylarsine oxide (TPA[ox]) and phenylarsonic acid (PDCA[ox]) were used as chemicals in in vitro experiments. Glutathione (GSH) conjugates of DA, DM and PDCA-related chemicals were found to be the most dominant metabolites, and methylated metabolites were detected as well, suggesting that these compounds are metabolised in the presence of cod liver enzymes. TPA[ox] was the only compound tested that did not form a GSH conjugate or methylated metabolite, indicating a different biotransformation pathway for this compound. Furthermore, hydroxylated metabolites were detected for each tested chemical. Due to their reactive nature, GSH conjugates may be difficult to detect in fish samples from CWA dumpsites. In contrast, both methylated and hydroxylated metabolites of phenylarsenic chemicals are promising target chemicals for the detection of CWA-related contamination in fish.

Tissue- and Region-Specific Accumulation of Arsenic Species, Especially in the Brain of Mice, After Long-term Arsenite Exposure in Drinking Water.

Arsenic is identified as a known carcinogen and ubiquitously exists in nature. It appears that accumulation of inorganic arsenic (iAs) and its methylated metabolites in various tissues is closely correlated with the long-term toxicity and carcinogenicity of this metalloid. In this study, various arsenic species in murine tissues, especially in the cerebral cortex, cerebellum, and hippocampus, were determined after long-term exposure to 25, 50, 100, and 200mg/L sodium arsenite in drinking water for 1 and 12months. Our data showed that the amount of total arsenic (TAs) increased in an obvious dose-dependent manner in various tissues, and TAs levels were in the order of urinary bladder > brain > lung > liver > kidney > spleen. Furthermore, iAsIII and DMA could be observed in all tissues and brain regions with DMA being the predominant metabolite. The bladder, brain, and lung orderly contained the higher levels of DMA, while the liver, kidney, and spleen accumulated the higher proportion of iAsIII. MMA was preferentially accumulated in the lung and bladder of mice regardless of arsenic exposure doses or duration. What's more, amazingly higher levels of MMA were observed in the hippocampus, which was distinguished from the cerebral cortex and cerebellum. Together with these results, our study clearly demonstrates that the accumulation of iAs and its methylated metabolites is tissue-specific and even not homogeneous among different brain regions in mice by long-term exposure to arsenite. Our study thus provides crucial information for recognizing arsenical neurotoxicity, and reducing the uncertainty in the risk assessment for this toxic metalloid.

Association of prenatal pesticide exposures with adverse pregnancy outcomes and stunting in rural Bangladesh

BackgroundPesticide exposure during pregnancy is thought to adversely affect fetal growth, which in turn may impact child growth, but results have been inconsistent across studies and few have explored these effects in developing countries. ObjectivesTo quantify urinary concentrations of pesticide biomarkers in early pregnancy (<16 weeks’ gestation), and to estimate the association of these concentrations with preterm birth, low birth weight, small for gestational age, and stunting at ~1 and 2 years of age. MethodsEight pesticide biomarkers were quantified in urine collected from 289 pregnant women (aged 18–40 years) participating in a birth cohort study in Bangladesh. Anthropometry measurements were conducted on the index child at birth and approximately 1 and 2 years of age. A directed acyclic graph was used to identify minimal sufficient adjustment sets. Log-binomial regression was used to estimate the relative risk (RR) with 95% confidence intervals (CI). Results3,5,6-trichloro-2-pyridinol (TCPY), a metabolite of chlorpyrifos and chlorpyrifos methyl, and 4-nitrophenol, a metabolite of parathion and methyl parathion, were detected in nearly all women with geometric mean (95% CI) values of 3.17 (2.82–3.56) and 18.66 (17.03–20.46) µg/g creatinine, respectively. 3-phenoxybenzoic acid (3-PBA), a non-specific metabolite of several pyrethroids, and 2-isopropyl-4-methyl-6-hydroxypyrimidine (IMPY), a diazinon metabolite, were detected in 19.8% and 16.1% of women, respectively. The remaining four pesticide biomarkers were detected in <10% of women. Women in the highest quartile of 4-nitrophenol were more than 3 times more likely to deliver preterm than women in the lowest quartile: unadjusted RR (95% CI), 3.57 (1.65, 7.73). Women in the highest quartile of 4-nitrophenol were also at increased risk of having a child born small for gestational age: RR (95% CI) adjusted for household income, maternal education, and maternal total energy and meat intake, 3.81 (1.10, 13.21). Women with detectable concentrations of IMPY were at increased risk of having a child born with low birth weight compared to women with non-detectable concentrations: adjusted RR (95% CI), 2.13 (1.12, 4.08). We observed no association between any of the pesticide biomarkers and stunting at 1 or 2 years of age. DiscussionExposure to the insecticides parathion and diazinon during early pregnancy may increase the risk of adverse birth outcomes.

Simultaneous pressurized liquid extraction and clean-up for the determination of metabolites in complex environmental solid matrices

Parabens and pharmaceuticals are two of the most significant groups of pollutants of emerging concern. Nevertheless, in spite that their presence in the environment is well-known, to the date, there is scarce information about the presence of their metabolites that can be present at higher concentrations in the environment, be more toxic and be transformed into the parent compound. In this work, an analytical method has been developed and validated for the first-time simultaneous determination of metabolites of methyl- and propylparabens, caffeine, carbamazepine, diclofenac, ibuprofen and sulfamethoxazole and their parent compounds in soil, compost and digested sludge. Box-Behnken experimental design was applied for method optimisation due to the high number of experimental variables to optimize and the different physical-chemical properties of the target compounds. The method involves simultaneous sample extraction and clean-up by selective pressurized liquid extraction and analytical determination in a single run by liquid chromatography-tandem mass spectrometry (LC-MS/MS). Good linearity, accuracy (mainly from 80 to 112%) and precision (<11%) was obtained. Method quantification limits were in the range from 0.12 to 14.4 ng g−1 dry matter. The application of the method to soil, compost and digested sludge revealed that metabolites of parabens, carbamazepine, diclofenac and ibuprofen were at similar or higher concentrations than their parent compounds in digested sludge and the presence of metabolites of parabens, caffeine and carbamazepine in compost.

125 - Altered DNA Methylation and Serum Levels of Metabolites is Associated With Type 2 Diabetes in Adolescents

Worldwide, it is currently estimated that 425 million adults have type 2 diabetes (T2D) and rates of T2D are also increasing among adolescents. Exposure to diabetes during pregnancy is strongly associated with early onset obesity, dysglycemia and T2D in the offspring. One current theory for the trend of rising T2D among children is that more women in their childbearing years are overweight and at risk of diabetes during pregnancy. The mechanisms involved are not understood, but the development of T2D in the offspring years after the initial exposure to diabetes in utero suggests the possible involvement of epigenetics, a form of cellular memory. One specific epigenetic mark, DNA methylation, is established in utero. Thus, DNA methylation could link in utero exposure to diabetes during pregnancy to gene expression patterns that affect the risk of T2D development in the offspring.

Dietary Quercetin and Kaempferol: Bioavailability and Potential Cardiovascular-Related Bioactivity in Humans.

Fruit and vegetable intake has been associated with a reduced risk of cardiovascular disease. Quercetin and kaempferol are among the most ubiquitous polyphenols in fruit and vegetables. Most of the quercetin and kaempferol in plants is attached to sugar moieties rather than in the free form. The types and attachments of sugars impact bioavailability, and thus bioactivity. This article aims to review the current literature on the bioavailability of quercetin and kaempferol from food sources and evaluate the potential cardiovascular effects in humans. Foods with the highest concentrations of quercetin and kaempferol in plants are not necessarily the most bioavailable sources. Glucoside conjugates which are found in onions appear to have the highest bioavailability in humans. The absorbed quercetin and kaempferol are rapidly metabolized in the liver and circulate as methyl, glucuronide, and sulfate metabolites. These metabolites can be measured in the blood and urine to assess bioactivity in human trials. The optimal effective dose of quercetin reported to have beneficial effect of lowering blood pressure and inflammation is 500 mg of the aglycone form. Few clinical studies have examined the potential cardiovascular effects of high intakes of quercetin- and kaempferol-rich plants. However, it is possible that a lower dosage from plant sources could be effective due to of its higher bioavailability compared to the aglycone form. Studies are needed to evaluate the potential cardiovascular benefits of plants rich in quercetin and kaempferol glycoside conjugates.

Current promising treatment strategy for glioblastoma multiform: A review.

Glioblastoma multiform (GBM) is a heterogeneous group of primary neoplasm resistant to conventional therapies. Due to their infiltrative nature it not fully isolated by aggressive surgery, radiation and chemotherapy showing poor prognosis in glioma patients. Unfortunately, diagnosed patients die within 1.5-2 year treatment schedule. Currently temozolomide (TMZ) is the first choice for the prognosis of GBM patients. TMZ metabolites methyl triazen imidazol carboxamide form complex with alkyl guanine alkyl transferase (O6 MGMT- DNA repair protein) induced DNA damage following resistance properties of TMZ and inhibit the overall survival of the patients. Last few decades different TMZ conjugated strategy is developed to overcome the resistance and enhance the chemotherapy efficacy. The main aim of this review is to introduce the new promising pharmaceutical candidates that significantly influence the therapeutic response of the TMZ in context of targeted therapy of glioblastoma patients. It is hoped that this proposed strategy are highly effective to overcome the current resistance limitations of TMZ in GBM patients and enhance the survival rate of the patients.

Arsenite and its trivalent methylated metabolites inhibit glucose-stimulated calcium influx and insulin secretion in murine pancreatic islets.

Chronic exposure to inorganic arsenic (iAs), a common drinking water and food contaminant, has been associated with an increased risk of type 2 diabetes in population studies worldwide. Several mechanisms underlying the diabetogenic effects of iAs have been proposed through laboratory investigations. We have previously shown that exposure to arsenite (iAs(III)) or its methylated trivalent metabolites, methylarsonite (MAs(III)) and dimethylarsinite (DMAs(III)), inhibits glucose-stimulated insulin secretion (GSIS) in pancreatic islets, without significant effects on insulin expression or insulin content. The goal of the present study was to determine if iAs(III) and/or its metabolites inhibit Ca2+ influx, an essential mechanism that regulates the release of insulin from β cells in response to glucose. We found that in vitro exposures for 48h to non-cytotoxic concentrations of iAs(III), MAs(III), and DMAs(III) impaired Ca2+ influx in isolated murine pancreatic islets stimulated with glucose. MAs(III) and DMAs(III) were more potent inhibitors of Ca2+ influx than iAs(III). These arsenicals also inhibited Ca2+ influx and GSIS in islets treated with depolarizing levels of potassium chloride in the absence of glucose. Treatment with Bay K8644, a Cav1.2 channel agonist, did not restore insulin secretion in arsenical-exposed islets. Tolbutamide, a KATP channel blocker, prevented inhibition of insulin secretion in MAs(III)- and DMAs(III)-exposed islets, but only marginallyin islets exposed to iAs(III). Our findings suggest that iAs(III), MAs(III), and DMAs(III) inhibit glucose-stimulated Ca2+ influx in pancreatic islets, possibly by interfering with KATP and/or Cav1.2 channel function. Notably, the mechanisms underlying inhibition of GSIS by iAs(III) may differ from those of its trivalent methylated metabolites.

Accumulation of plasma levels of anthocyanins following multiple saskatoon berry supplements

1. Anthocyanins are a subgroup of flavonoids responsible for the blue, purple and red color of many fruits, flowers and leaves. Consumption of foods rich in anthocyanins is associated with a reduced risk of cardiovascular disease and cancer. Most food intervention studies employ once or twice per day dose schedules. 2. The current study demonstrated that plasma concentrations of cyanidin-3-galactoside and cyanidin-3-xyloside, the two major components of saskatoon berries, were significantly increased following three consecutive saskatoon berry supplements 4 hours apart. This accumulation is due to the residual concentrations of anthocyanins at the time of second and third supplements. 3. Accumulation was especially pronounced for peonidin-3-glucoside and peonidin-3-galactoside, the methylated metabolites of cyanidin-3-glucoside and cyanidin-3-galactoside, respectively. Little or no accumulation was observed for cyanidin-3-arabinoside and cyanidin-3-glucoside, two other components of saskatoon berries, possibly due to their short half-lives. 4. Thus, taking anthocyanin supplements with every meal would provide higher plasma concentrations for some anthocyanins and their metabolites than the once or twice-a-day dose regimens.