Characterization of Preclinical Pharmacokinetic Properties and Prediction of Human PK Using a Physiologically Based Pharmacokinetic Model for a Novel Anti-Arrhythmic Agent Sulcardine Sulfate.

PURPOSE: Sulcardine sulfate (Sul) is a novel antiarrhythmic agent with promising pharmacological properties, which is currently being evaluated in several clinical trials as an oral formulation. To meet the medication needs of patients with acute conditions, the injection formulation of Sul has been developed. The objective of this study was to systemically investigate the pharmacokinetic profiles of Sul after intravenous infusion. METHODS: This research included the plasma protein binding and metabolic stability studies in vitro, plasma pharmacokinetics, biodistribution, excretion studies in animals, and the prediction of the clinical PK of Sul injection using a physiologically based pharmacokinetics (PBPK) model. RESULTS: The metabolic stability was similarly in dogs and humans but lower in rats. The plasma protein binding rates showed a concentration-dependent manner and species differences. The pharmacokinetic behavior after intravenous administration was linear in rats within the dose range of 30-90 mg/kg, but nonlinear in dogs within 30-60 mg/kg. Sul could be rapidly and widely distributed in multiple tissues after intravenous administration. About 12% of the parent compound were excreted via the urine and only a small fraction via bile and feces,and eight metabolites were found and identified in the rat excretion. The PBPK models were developed and simulated the observed PK date well in both rats and dogs. The PBPK model refined with human data predicted the PK characteristics of the first intravenous infusion of Sul in human. CONCLUSIONS: Our study systematically explored the pharmacokinetic characteristics of Sul and successfully developed the PBPK model to predict of its clinical PK.

Interaction of Phytocompounds of Echinacea purpurea with ABCB1 and ABCG2 Efflux Transporters.

Preparations of Echinacea purpurea (E. purpurea) are widely used for the management of upper respiratory infections, influenza, and common cold, often in combination with other conventional drugs. However, the potential of phytochemical constituents of E. purpurea to cause herb-drug interactions via ABCB1 and ABCG2 efflux transporters remains elusive. The purpose of this study was to investigate the impact of E. purpurea-derived caffeic acid derivatives (cichoric acid and echinacoside) and tetraenes on the mRNA and protein expression levels as well as on transport activity of ABCB1 and ABCG2 in intestinal (Caco-2) and liver (HepG2) cell line models. The safety of these compounds was investigated by estimating EC20 values of cell viability assays in both cell lines. Regulation of ABCB1 and ABCG2 protein in these cell lines were analyzed after 24 h exposure to the compounds at 1, 10, and 50 µg/mL. Bidirectional transport of 0.5 µg/mL Hoechst 33342 and 5 µM rhodamine across Caco-2 monolayer and profiling for intracellular concentrations of the fluorophores in both cell lines were conducted to ascertain inhibition effects of the compounds. Cichoric acid showed no cytotoxic effect, while the EC20 values of tetraenes and echinacoside were 45.0 ± 3.0 and 52.0 ± 4.0 µg/mL in Caco-2 cells and 28.0 ± 4.3 and 62.0 ± 9.9 µg/mL in HepG2 cells, respectively. In general, the compounds showed heterogeneous induction of ABCB1 with the strongest 3.6 ± 1.2-fold increase observed for 10 µg/mL tetraenes in Caco-2 cells (p < 0.001). However, the compounds did not induce ABCG2. None of the phytocompounds inhibited significantly net flux of the fluorophores across Caco-2 monolayers. Overall, tetraenes moderately induced ABCB1 but not ABCG2 in Caco-2 and HepG2 cells while no compound significantly inhibited activity of these transporters at clinically relevant concentration to cause herb-drug interactions.

Modulation of Intestinal Phosphate Transport in Young Goats Fed a Low Phosphorus Diet.

The intestinal absorption of phosphate (Pi) takes place transcellularly through the active NaPi-cotransporters type IIb (NaPiIIb) and III (PiT1 and PiT2) and paracellularly by diffusion through tight junction (TJ) proteins. The localisation along the intestines and the regulation of Pi absorption differ between species and are not fully understood. It is known that 1,25-dihydroxy-vitamin D3 (1,25-(OH)2D3) and phosphorus (P) depletion modulate intestinal Pi absorption in vertebrates in different ways. In addition to the apical uptake into the enterocytes, there are uncertainties regarding the basolateral excretion of Pi. Functional ex vivo experiments in Ussing chambers and molecular studies of small intestinal epithelia were carried out on P-deficient goats in order to elucidate the transepithelial Pi route in the intestine as well as the underlying mechanisms of its regulation and the proteins, which may be involved. The dietary P reduction had no effect on the duodenal and ileal Pi transport rate in growing goats. The ileal PiT1 and PiT2 mRNA expressions increased significantly, while the ileal PiT1 protein expression, the mid jejunal claudin-2 mRNA expression and the serum 1,25-(OH)2D3 levels were significantly reduced. These results advance the state of knowledge concerning the complex mechanisms of the Pi homeostasis in vertebrates.

The bioavailability and excretion of an antitussive compound IAsp-N-Glc in rats by validated UPLC-MS/MS methods.

IAsp-N-Glc is a potential antitussive agent that is first reported to be isolated from Ginkgo Semen, but the bioavailability and excretion of IAsp-N-Glc are unknown. Therefore, we carried out our study to obtain the bioavailability and excretion profiles of IAsp-N-Glc in rats. Rapid, specific, and reliable quantification methods for the measurement of IAsp-N-Glc in rat plasma and fecal samples by using ultra-high-performance liquid chromatography coupled with triple quadrupole mass spectrometry were developed and validated. A C18 column was used for the separation of IAsp-N-Glc and internal standards, and water (containing 0.1% formic acid) and acetonitrile were chosen as the mobile phase for the separation in the flow-gradient mode. In the ranges of 37.5-7500 ng/mL and 120-30000 ng/mL, the calibration curves of IAsp-N-Glc exhibited satisfactory linearity for plasma and fecal samples with each linear correlation coefficient higher than 0.99, respectively. The methods were reproducible and reliable. The analytes were stable, and no apparent matrix effects were observed. The bioanalytical methods were successfully used to study the pharmacokinetics and excretion of IAsp-N-Glc in rats. Oral administration of IAsp-N-Glc exhibited a low absolute oral bioavailability (1.83±0.09%), and 59.63±6.29% of IAsp-N-Glc was excreted in feces. This report is the first to describe the bioavailability and excretion of IAsp-N-Glc in rats and will lay the foundation for the in-depth study and drug development of IAsp-N-Glc.

Evaluation of In Vitro Models for Assessment of Human Intestinal Metabolism in Drug Discovery.

Although intestinal metabolism plays an important role in drug disposition, early predictions of human outcomes are challenging, in part because of limitations of available in vitro models. To address this, we have evaluated three in vitro models of human intestine (microsomes, permeabilized enterocytes, and cryopreserved intestinal mucosal epithelium) as tools to assess intestinal metabolism and estimate the fraction escaping gut metabolism (f g) in drug discovery. The models were tested with a chemically diverse set of 32 compounds, including substrates for oxidoreductive, hydrolytic, and conjugative enzymes. Liquid chromatography-high-resolution mass spectrometry was used to quantify substrate disappearance [intrinsic clearance (CLint)] and qualify metabolite formation (quantitative-qualitative bioanalysis). Fraction unbound in the incubation (f u,inc) was determined by rapid equilibrium dialysis. Measured in vitro results (CLint and f u,inc) were supplemented with literature data [passive Caco-2 apical to basolateral permeability, enterocyte blood flow, and intestinal surface area (A)] and combined using a midazolam-calibrated Q gut model to predict human f g values. All three models showed reliable CYP and UDP-glucuronosyltransferase activities, but enterocytes and mucosa may offer advantages for low-clearance compounds and alternative pathways (e.g., sulfation, hydrolases, and flavin-containing monooxigenases). Early predictions of human f g values were acceptable for the high-f g compounds (arbitrarily f g > 0.7). However, predictions of low- and moderate-f g values (arbitrarily f g < 0.7) remain challenging, indicating that further evaluation is needed (e.g., saturation effects and impact of transporters) but not immediate compound avoidance. Results suggest that tested models offer an additional value in drug discovery, especially for drug design and chemotype evaluation. SIGNIFICANCE STATEMENT: We found that cellular models of the human gut (permeabilized enterocytes and cryopreserved intestinal mucosa) offer an alternative to and potential advantage over intestinal microsomes in studies of drug metabolism, particularly for low-clearance compounds and alternative pathways (e.g., sulfation, hydrolases, and flavin-containing monooxigenases). The predictivity of human fraction escaping gut metabolism for common CYP and UDP-glucuronosyltransferase substrates based on the Q gut model is still limited, however, and appropriate further evaluation is recommended.

Mangiferin promotes intestinal elimination of uric acid by modulating intestinal transporters.

Increasing evidence shows that the intestinal tract plays an important role in maintaining urate homeostasis and might be a potential therapeutic target for hyperuricaemia. However, uric acid-lowering drugs available in the clinic do not target intestinal excretion as a therapeutic strategy. We previously reported that mangiferin had potent hypouricaemic effects in hyperuricaemic animals. However, the underlying mechanisms are not completely clear. Here, we investigated the effects of mangiferin on the intestinal excretion of urate and its underlying mechanisms. The data revealed that mangiferin concentration-dependently promoted the intestinal secretion of endogenous urate in in situ intestinal closed loops in normal and hyperuricaemic mice, as well as inhibited the absorption of exogenous uric acid perfused into the intestinal loops in rats. Administration of mangiferin not only decreased the serum urate levels in the hyperuricaemic mice but also increased the protein expression of ATP-binding cassette transporter, subfamily G, member 2 (ABCG2) and inhibited the protein expression of glucose transporter 9 (GLUT 9) in the intestine. These findings suggested that intestinal ABCG2 and GLUT9 might be pivotal and possible action sites for the observed hypouricaemic effects. Moreover, no significant changes in intestinal xanthine oxidoreductase activities were observed, suggesting that mangiferin did not affect intestinal uric acid generation in the hyperuricaemic mice. Overall, promoting intestinal elimination of urate by upregulating ABCG2 expression and downregulating GLUT9 expression might be an important mechanism underlying mangiferin lowering serum uric acid levels. Mangiferin supplementation might be beneficial for the prevention and treatment of hyperuricaemia.

Research Note: Phosphorus digestibility in conventional canola meal determined using different balance assays.

Three experiments were conducted to determine ileal P digestibility and excreta P retention values for canola meal (CM) using 3 different types of balance assays. The first experiment was an ad libitum-fed chick experiment which evaluated the effect of phytase on ileal P digestibility and excreta P retention values. Chicks were fed a P-deficient cornstarch-dextrose-45% CM basal diet (0.13% nonphytate P) as diet 1 or that diet plus 125 or 250 FTU/kg of phytase, respectively, from 8 to 21 D of age. The digestibility/retention of P was 38% and phytase linearly increased both ileal digestibility and excreta retention of P (P < 0.05). The second experiment was a precision-fed chick assay conducted to determine ileal digestibility of P in CM at 21 D. Mean ileal P digestibility was determined to be 47.5% in chicks fed 6 g and 40.0% in chicks fed 9 g of CM and the values were not significantly different. Experiment 3 was an ad libitum-fed chick assay to determine ileal P digestibility and excreta P retention for CM with and without increasing levels of dietary supplemental Ca. The chicks were fed P-deficient - dextrose - CM diets containing increasing levels of 13.5, 27, 40.5, or 54% CM, respectively, with Ca:nonphytate P ratio maintained at 2:1 in diets 1-4 and 6:1 in diets 5-8. Based on regression analysis of ileal digesta or excreta P output on dietary P concentration, digestibility/retention of P in CM was 30%. Ileal P digestibility (and to a lesser extent excreta P retention) at 21 D was reduced by increased Ca:P ratio. The results of this study indicated that the 3 balance assays yielded reasonably consistent values of 30-40% for P digestibility/retention and ileal P digestibility was greatly affected by Ca:P ratio.

Pharmacokinetics, bioavailability, excretion, and metabolic analysis of Schisanlactone E, a bioactive ingredient from Kadsura heteroclita (Roxb) Craib, in rats by UHPLC-MS/MS and UHPLC-Q-Orbitrap HRMS.

Schisanlactone E (SE) is a bioactive ingredient extracted from the stem of Kadsura heteroclita (Roxb) Craib. SE has various pharmacological activity such as anti-tumor and anti-leukemia effects. However, its absorption, distribution, metabolism, and excretion have rarely been examined. In this study, new quali-quantitative analytical methods were developed for metabolic and pharmacokinetic studies of SE in rats. A UHPLC-MS/MS method was developed to determine SE in rat plasma, urine, and feces. Samples were precipitated with methanol and analyzed in multiple reaction monitoring mode. The established method was validated and applied to the pharmacokinetics, bioavailability, and excretion analysis of SE after oral (6 mg/kg) or intravenous (2 mg/kg) administration. The absolute oral bioavailability of SE was approximately 79.3%. After oral administration, SE was mainly excreted via feces with a rate of 41.7% for 48 h. SE could not be detected in urine. Furthermore, a UHPLC-Q-Orbitrap HRMS method was developed for the metabolite screening of SE in rat plasma, urine, and feces. Metabolites were extracted by solid phase extraction and analyzed with full MS/dd-MS2 scan mode. As a result, 15 metabolites including 11 phase I and 4 phase II metabolites were identified by a three-step analytical strategy. The carboxyl group, the five membered ring, and the six membered α,ß-unsaturated lactone ring of SE could be predicted as the main metabolic sites. This study provides comprehensive insights into the pharmacokinetic and metabolic profiles of SE, and would be valuable for future development and utilization of SE and Kadsura heteroclita.

Stevia residue extract increases intestinal uric acid excretion via interactions with intestinal urate transporters in hyperuricemic mice.

Hyperuricemia (HUA) is a metabolic disorder that occurs due to the overproduction or under-excretion of uric acid (UA) and is directly linked to the development of many life-threatening diseases. There is a growing interest among many researchers regarding how to overcome the encumbrance of HUA because conventional drugs are associated with multiple side effects. Thus, the present project has been designed to utilize flavonoids and chlorogenic acid-enriched stevia residue extract (STVRE) to combat HUA. The results show that supplementation with STVRE (200 and 400 mg per kg bw) inhibits the XOD enzyme in serum, duodenum, jejunum, and ileum tissues. Moreover, UA levels in the STVRE groups were also significantly (p < 0.05) decreased in serum, duodenum, jejunum, and ileum tissues and juices. STVRE also improved the intestinal morphology and oxidative biomarkers in duodenum, jejunum, and ileum tissues. Protein and mRNA expressions of ABCG2 were upregulated, whereas GLUT9 was downregulated in the STVRE-treated groups as compared with the model control group. The supplementation of STVRE significantly attenuated hyperuricemia and oxidative stress, upregulated ABCG2 and downregulated GLUT9 (protein and mRNA) expression in hyperuricemic mice. The results of our study revealed that the by-product of stevia has the potential to combat hyperuricemia, and can be used as a functional ingredient in the development of nutraceutical products.

Iron and Zinc Homeostasis and Interactions: Does Enteric Zinc Excretion Cross-Talk with Intestinal Iron Absorption?

Iron and zinc are essential micronutrients required for growth and health. Deficiencies of these nutrients are highly prevalent among populations, but can be alleviated by supplementation and food fortification. Cross-sectional studies in humans showed positive association of serum zinc levels with hemoglobin and markers of iron status. Dietary restriction of zinc or intestinal specific conditional knock out of ZIP4 (SLC39A4), an intestinal zinc transporter, in experimental animals demonstrated iron deficiency anemia and tissue iron accumulation. Similarly, increased iron accumulation has been observed in cultured cells exposed to zinc deficient media. These results together suggest a potential role of zinc in modulating intestinal iron absorption and mobilization from tissues. Studies in intestinal cell culture models demonstrate that zinc induces iron uptake and transcellular transport via induction of divalent metal iron transporter-1 (DMT1) and ferroportin (FPN1) expression, respectively. It is interesting to note that intestinal cells are exposed to very high levels of zinc through pancreatic secretions, which is a major route of zinc excretion from the body. Therefore, zinc appears to be modulating the iron metabolism possibly via regulating the DMT1 and FPN1 levels. Herein we critically reviewed the available evidence to hypothesize novel mechanism of Zinc-DMT1/FPN1 axis in regulating intestinal iron absorption and tissue iron accumulation to facilitate future research aimed at understanding the yet elusive mechanisms of iron and zinc interactions.

Effects of the different levels of dietary trace elements from organic or inorganic sources on growth performance, carcass traits, meat quality, and faecal mineral excretion of broilers.

This experiment was conducted to evaluate the effects of different sources and levels of trace elements on growth performance, carcass composition and mineral excretion levels of broilers. In a completely randomised experimental design, 900 one-day-old male Ross-308 broilers were assigned to 5 treatments, with 6 replicates of 30 birds each. The control group (CITE) was fed with a basal diet containing regular inclusion levels of inorganic trace elements. Treatment groups were supplied with reduced levels (30% and 50% of the regular level) of inorganic (ITE) or organic trace elements (OTE), respectively. Groups 50% ITE, 30% OTE and 50% OTE diets had equivalent average daily gain (ADG), average daily feed intake (ADFI), feed to gain ratio (F/G ratio) and mortality rate compared with group CITE in any phase. However, compared with group CITE chicks in group 30% ITE have lower ADG and ADFI and higher F/G ratio. The carcass yields were not affected by dietary treatments. Compared with group CITE, in groups 30% ITE, 50% ITE, 30% OTE and 50% OTE the shear force values of the breast muscle were only 71.8%, 83.4%, 63.5% and 59.4% (p < 0.05), respectively. Birds received diets containing reduced levels of trace elements had diminished excretions of Mn and Zn throughout the entire period (p < 0.01). In conclusion, the reduced supplementation of trace elements had no or slightly negative impact on growth performance, carcass yield and meat quality, but decreased faecal mineral excretion. Moreover, the trace element supply as OTE played a limited role on performance and excretion and was only partly beneficial for animal performance in case the trace element supply was reduced to 30%.

Comparative analysis of fecal phenolic content between normal and obese rats after oral administration of tea polyphenols.

Tea polyphenols (TP) have many health benefits, but most are metabolized into low molecular-weight phenolic acids after oral administration. In the present study, the absorption, metabolism, and excretion of catechins in rats fed a normal chow diet and in obese rats fed a high-fat and high-sugar (HFHS) diet were compared. After a ten-day oral administration of TP (500 mg per kg bw), the plasma levels of (-)-epigallocatechin gallate (EGCG) and (-)-gallocatechin gallate (GCG) in obese rats were significantly lower than those in the normal group. In obese rats, the fecal levels of EGCG, (-)-epicatechin gallate (ECG) and GCG were significantly enhanced. Ten phenolic metabolites of TP were quantitatively analyzed, and the results showed that 4-hydroxyphenylacetic acid was the primary metabolite in feces and plasma. The plasma and fecal concentrations of 4-hydroxyphenylacetic acid in the obese group were significantly lower than those in normal rats, but the levels of 4-hydroxyphenylpropionic acid in plasma and feces were increased. The content of other phenolic acids was also dramatically changed. These results suggested that a HFHS diet might influence the excretion of tea catechins, leading to insufficient metabolism of catechins by the gut microflora.

Comparison of the Oral Absorption, Distribution, Excretion, and Bioavailability of Zinc Sulfate, Zinc Gluconate, and Zinc-Enriched Yeast in Rats.

SCOPE: The oral absorption, distribution, excretion, and bioavailability of zinc sulfate (ZnS), zinc gluconate (ZnG), and zinc-enriched yeast (ZnY) in rats are fully and systemically compared for the first time. METHODS AND RESULTS: After zinc compounds were orally administered to rats at a single dose of 4 mg Zn kg-1 , blood, tissues, urine, and feces at different time points were collected for the quantification of zinc concentration. Blood was also harvested for the zinc assay in the multiple-dose administration. Plasma zinc levels among three zinc compounds showed no difference, and zinc was widely distributed in various tissues with the level sequence of bone > liver > pancreas > testes. The net Zn balance was 2.993, 5.125, and 7.482% for ZnS, ZnG, and ZnY, respectively. CONCLUSION: ZnS, ZnG, and ZnY show equivalent bioavailability based on plasma and tissues zinc levels, although ZnY was statistically more absorbed and retained than ZnS and ZnG based on the excretion amount.

The oral bioavailability, excretion and cytochrome P450 inhibition properties of epiberberine: an in vivo and in vitro evaluation.

Epiberberine (EPI) is a novel and potentially effective therapeutic and preventive agent for diabetes and cardiovascular disease. To evaluate its potential value for drug development, a specific, sensitive and robust high-performance liquid chromatography-tandem mass spectrometry assay for the determination of EPI in rat biological samples was established. This assay was used to study the pharmacokinetics, bioavailability and excretion of EPI in rats after oral administration. In addition, a cocktail method was used to compare the inhibition characteristics of EPI on cytochrome P450 (CYP450) isoforms in human liver microsomes (HLMs) and rat liver microsomes (RLMs). The results demonstrated that EPI was rapidly absorbed and metabolized after oral administration (10, 54 or 81 mg/kg) in rats, with Tmax of 0.37-0.42 h and T1/2 of 0.49-2.73 h. The Cmax and area under the curve values for EPI increased proportionally with the dose, and the oral absolute bioavailability was 14.46%. EPI was excreted mainly in bile and feces, and after its oral administration to rats, EPI was eliminated predominantly by the kidneys. A comparison of the current half-maximal inhibitory concentration and Ki values revealed that EPI demonstrated an obvious inhibitory effect on CYP2C9 and CYP2D6. Furthermore, its effect was stronger in HLM than in RLM, more likely to be a result of noncompetitive inhibition.

Effect and mechanism of dioscin from Dioscorea spongiosa on uric acid excretion in animal model of hyperuricemia.

ETHNOPHARMACOLOGY RELEVANCE: Dioscin, a spirostane glycoside, the rhizoma of Dioscorea septemloba (Diocoreacea) is used for diuresis, rheumatism, and joints pain. Given the poor solubility and stability of Dioscin, we proposed a hypothesis that Dioscin's metabolite(s) are the active substance(s) in vivo to contribute to the reducing effects on serum uric acid levels. AIM OF THE STUDY: The aim of this study is to identify the active metabolite(s) of Dioscin in vivo and to explore the mechanism of its antihyperuricemic activity. MATERIALS AND METHODS: After oral administration of Dioscin in potassium oxonate (PO) induced hyperuricemia rats and adenine-PO induced hyperuricemia mice models, serum uric acid and creatinine levels, clearance of uric acid and creatinine, fractional excretion of uric acid, and renal pathological lesions were determined were used to evaluate the antihyperuricemic effects. Renal glucose transporter-9 (GLUT-9) and organic anion transporter-1 (OAT-1) expressions were analyzed by western blotting method. Renal uric acid excretion was evaluated using stably urate transporter-1 (URAT-1) transfected human epithelial kidney cell line. Intestinal uric acid excretion was evaluated by measuring the transcellular transport of uric acid in HCT116 cells. RESULTS: In hyperuricemia rats, both 25 and 50mg/kg of oral Dioscin decreased serum uric acid levels over 4h. In the hyperuricemia mice, two weeks treatment of Dioscin significantly decreased serum uric acid and creatinine levels, increased clearance of uric acid and creatinine, increased fractional excretion of uric acid, and reduced renal pathological lesions caused by hyperuricemia. In addition, renal GLUT -9 was significantly down-regulated and OAT-1 was up-regulated in Dioscin treated hyperuricemia mice. Dioscin's metabolite Tigogenin significantly inhibited uric acid re-absorption via URAT1 from 10 to 100µM. Diosgenin and Tigogenin increased uric acid excretion via ATP binding cassette subfamily G member 2 (ABCG2). CONCLUSION: Decreasing effect of Dioscin on serum uric acid level and enhancing effect on urate excretion were confirmed in hyperuricemia animal models. Tigogenin, a metabolite of Dioscin, was identified as an active substance with antihyperuricemic activity in vivo, through inhibition of URAT1 and promotion of ABCG2.

Xanthohumol, a hop-derived prenylated flavonoid, promotes macrophage reverse cholesterol transport.

Xanthohumol, a prominent prenyl flavonoid from the hop plant (Humulus lupulus L.), is suggested to be antiatherogenic since it reportedly increases high-density lipoprotein (HDL) cholesterol levels. It is not clear whether xanthohumol promotes reverse cholesterol transport (RCT), the most important antiatherogenic property of HDL; therefore, we investigated the effects of xanthohumol on macrophage-to-feces RCT using a hamster model as a CETP-expressing species. In vivo RCT experiments showed that xanthohumol significantly increased fecal appearance of the tracer derived from intraperitoneally injected [3H]-cholesterol-labeled macrophages. Ex vivo experiments were then employed to investigate the detailed mechanism by which xanthohumol enhanced RCT. Cholesterol efflux capacity from macrophages was 1.5-fold higher in xanthohumol-fed hamsters compared with the control group. In addition, protein expression and lecithin-cholesterol acyltransferase activity in the HDL fraction were significantly higher in xanthohumol-fed hamsters compared with the control, suggesting that xanthohumol promoted HDL maturation. Hepatic transcript analysis revealed that xanthohumol increased mRNA expression of abcg8 and cyp7a1. In addition, protein expressions of liver X receptor α and bile pump export protein were increased in the liver by xanthohumol administration when compared with the control, implying that it stimulated bile acid synthesis and cholesterol excretion to feces. In conclusion, our data demonstrate that xanthohumol improves RCT in vivo through cholesterol efflux from macrophages and excretion to feces, leading to antiatherosclerosis effects. It remains to be elucidated whether enhancement of RCT by xanthohumol could prove valuable in humans.

A dose-response crossover iodine balance study to determine iodine requirements in early infancy.

BACKGROUND: Optimal iodine intake during infancy is critical for brain development, but no estimated average requirement (EAR) is available for this age group. OBJECTIVE: We measured daily iodine intake, excretion, and retention over a range of iodine intakes in early infancy to determine the minimum daily intake required to achieve iodine balance. DESIGN: In a dose-response crossover study, we randomly assigned healthy infants (n = 11; mean ± SD age 13 ± 3 wk) to sequentially consume over 33 d 3 infant formula milks (IFMs) containing 10.5, 19.3, and 38.5 µg I/100 kcal, respectively. Each IFM was consumed for 11 d, consisting of a 6-d run-in period followed by a 4-d balance period and 1 run-out day. RESULTS: Iodine intake (mean ± SD: 54.6 ± 8.1, 142.3 ± 23.1, and 268.4 ± 32.6 µg/d), excretion (55.9 ± 8.6, 121.9 ± 21.7, and 228.7 ± 39.3 µg/d), and retention (-1.6 ± 8.3, 20.6 ± 21.6, and 39.8 ± 34.3 µg/d) differed among the low, middle, and high iodine IFM groups (P < 0.001 for all). There was a linear relation between daily iodine intake and both daily iodine excretion and daily iodine retention. Zero balance (iodine intake = iodine excretion, iodine retention = 0 µg/d) was achieved at a daily iodine intake of 70 µg (95% CI: 60, 80 µg). CONCLUSION: Our data indicate the iodine requirement in 2- to 5-mo-old infants is 70 µg/d. Adding an allowance for accumulation of thyroidal iodine stores would produce an EAR of 72 µg and a recommended dietary allowance of 80 µg. This trial was registered at clinicaltrials.gov as NCT02045784.

Statins increase hepatic cholesterol synthesis and stimulate fecal cholesterol elimination in mice.

Statins are competitive inhibitors of HMG-CoA reductase, the rate-limiting enzyme of cholesterol synthesis. Statins reduce plasma cholesterol levels, but whether this is actually caused by inhibition of de novo cholesterol synthesis has not been clearly established. Using three different statins, we investigated the effects on cholesterol metabolism in mice in detail. Surprisingly, direct measurement of whole body cholesterol synthesis revealed that cholesterol synthesis was robustly increased in statin-treated mice. Measurement of organ-specific cholesterol synthesis demonstrated that the liver is predominantly responsible for the increase in cholesterol synthesis. Excess synthesized cholesterol did not accumulate in the plasma, as plasma cholesterol decreased. However, statin treatment led to an increase in cholesterol removal via the feces. Interestingly, enhanced cholesterol excretion in response to rosuvastatin and lovastatin treatment was mainly mediated via biliary cholesterol secretion, whereas atorvastatin mainly stimulated cholesterol removal via the transintestinal cholesterol excretion pathway. Moreover, we show that plasma cholesterol precursor levels do not reflect cholesterol synthesis rates during statin treatment in mice. In conclusion, cholesterol synthesis is paradoxically increased upon statin treatment in mice. However, statins potently stimulate the excretion of cholesterol from the body, which sheds new light on possible mechanisms underlying the cholesterol-lowering effects of statins.

Effects of ellagic acid-rich extract of pomegranates peel on regulation of cholesterol metabolism and its molecular mechanism in hamsters.

The study investigated the effect of pomegranates ellagic acid (PEA) on blood cholesterol and investigated its effects on LXR/RXR/PPAR-ABCA1 nuclear receptors-signaling pathways of cholesterol metabolism on molecular level in hamsters. In this experiment, hamsters were randomly divided into two groups: the first group (NG, n = 9) was always fed the normal diet, whereas the other group (HFG, n = 45) was fed a high fat diet during the first 4 weeks and then fed the normal diet for the last 4 weeks. In HFG, which was divided into five groups (n = 9) during the last 4 weeks, three groups were treated with PEA at 44 mg per kg bw, 88 mg per kg bw and 177 mg per kg bw, one group was treated with simvastatin at 1.77 mg per kg bw, and one was given sterile double-distilled water. The data validated that PEA dose-dependently decreased plasma total cholesterol and triglyceride level accompanied by a greater excretion of fecal bile acid. The result of RT-PCR revealed that PEA up-regulated liver X receptor (LXRα), peroxisome proliferator-activated receptor α (PPARα), peroxisome proliferator-activated receptor γ (PPARγ) and their downstream gene ATP-binding cassette transporter A1 (ABCA1), with no effect on retinoid X receptor (RXRα). PEA promoted cholesterol removal by enhancing fecal bile acid and up-regulation of the two pathways, LXR/PPAR-ABCA1. Moreover, PEA was stronger than simvastatin in some aspects.

Fructan supplementation of senior cats affects stool metabolite concentrations and fecal microbiota concentrations, but not nitrogen partitioning in excreta.

Fructan supplementation of a commercially available canned cat food was evaluated using senior (≥ 9 yr) cats to assess nitrogen (N) partitioning in excreta and stool metabolite and microbiota concentrations. Oligofructose (OF) or SynergyC (OF+IN) were added to the diet individually at 1% (dry weight basis). Cats were acclimated to the control diet for 7 d and then were randomly assigned to 1 of 3 treatment groups for 21 d (n = 6). Feces and urine were collected on d 22 through 28. No differences were observed in food intake; fecal output, DM percentage, score, pH, or short- or branched-chain fatty acids, fecal and urinary ammonia output, urinary felinine concentrations, or N retention. Supplemental OF+IN tended to decrease N digestibility (P = 0.102) and Bifidobacteria spp. (P = 0.073) and decrease fecal indole (P < 0.05), tyramine (P < 0.05), and Escherichia coli (P < 0.05) concentrations. Both fructan-supplemented treatments decreased (P < 0.05) fecal histamine concentrations. The tendency to a lower apparent N digestibility was likely due to increased colonic microbial protein synthesis of fructan-supplemented cats. Fructan supplementation may benefit senior cats as it modulates stool odor-forming compounds and decreases some protein catabolites and pathogenic gut microbiota concentrations without affecting N retention.