Gender difference in the pharmacokinetics and metabolism of VX-548 in rats

VX-548 is a sodium channel blocker, which acts as an analgesic. This study aims to investigate the gender differences in the pharmacokinetics and metabolism of VX-548 in rats. After intravenous administration, the area under the curve (AUC0-t) of VX-548 was much higher in female rats (1505.8 ± 47.3 ng·h/mL) than in male rats (253.8 ± 6.3 ng·h/mL), and the clearance in female rats (12.5 ± 0.8 mL/min/kg) was much lower than in male rats (65.1 ± 1.7 mL/min/kg). After oral administration, the AUC0-t in female rats was about 50-fold higher than that in male rats. The oral bioavailability in male rats was 11% while it was 96% in female rats. An in vitro metabolism study revealed that the metabolism of VX-548 in female rat liver microsomes was much slower than in male rats. Further metabolite identification suggested that the significant gender difference in pharmacokinetics was attributed to demethylation. The female rat liver microsomes showed a limited ability to convert VX-548 into desmethyl VX-548. Phenotyping experiments indicated that the formation of desmethyl VX-548 was mainly catalyzed by CYP3A2 and CYP2C11 using rat recombinant CYPs. Overall, we revealed that the pharmacokinetics and metabolism of VX-548 in male and female rats showed significant gender differences.

Preclinical safety, toxicokinetics and metabolism of BIIB131, a novel prothrombolytic agent for acute stroke

BIIB131, a small molecule, is currently in Phase 2 for the treatment of acute ischemic stroke. Safety and metabolism of BIIB131 were evaluated following intravenous administration to rats and monkeys. Exposure increased dose-proportionally in rats up to 60 mg/kg and more than dose-proportionally in monkeys at greater than 10 mg/kg accompanied by prolonged half-life and safety findings. The BIIB131 was poorly metabolized in microsomes with no inhibition of CYPs. BIIB131-glucuronide, formed by UGT1A1, accounted for 21.5% metabolism in human hepatocytes and 28-40% in rat bile. In rats, excretion was primarily via the bile. BIIB131 inhibited the hERG and Nav1.5 cardiac channels by 39% but showed no effect on cardiovascular parameters in monkeys. Toxicology findings were limited to reversable hematuria, changes in urinary parameters and local effects. A MTD of 30 mg/kg was established in monkeys, the most sensitive species, at total plasma Cmax and AUC of 6- and 14-fold, respectively, greater than the NOAEL. The Phase 1 study started with intravenous 0.05 mg/kg and ascended to 6.0 mg/kg which corresponded to safety margins of 147- to 0.9-fold (for Cmax) within the linear drug exposure. Thus, the preclinical profile of BIIB131 has been appropriately characterized and supports its further clinical development.

Genetic Polymorphisms of UDP-Glucuronosyltransferases and Susceptibility to Antituberculosis Drug-Induced Liver Injury: A Systematic Review and Meta-Analysis

Methods

The PRISMA statement was strictly followed, and the protocol was registered in PROSPERO (CRD42022339317). The PICOS framework was used: patients received antituberculosis treatment, UGTs polymorphisms (mutants), UGTs polymorphisms (wild), AT-DILI, and case-control studies. Eligible studies were searched through nine databases up to April 27, 2022. The study's qualities were assessed by the revised Little's recommendations. Meta-analysis was conducted with a random-effects model using odds ratios (ORs) with 95% confidence intervals (95% CIs) as the effect size.

Results

Twelve case-control studies with 2128 cases and 4338 controls were included, and 32 single nucleotide polymorphisms (SNPs) in the seven UGT genes have been reported in Chinese and Korean. All studies were judged as high quality. The pooled results indicated that UGT1A1 rs3755319 (AC vs. AA, OR = 1.454, 95% CI: 1.100-1.921, P = 0.009), UGT2B7 rs7662029 (G vs. A, OR = 1.547, 95% CI: 1.249-1.917, P < 0.0001; GG + AG vs. AA, OR = 2.371, 95% CI: 1.779-3.160, P < 0.0001; AG vs. AA, OR = 2.686, 95% CI: 1.988-3.627, P < 0.0001), and UGT2B7 rs7439366 (C vs. T, OR = 0.585, 95% CI: 0.477-0.717, P < 0.0001; CC + TC vs. TT, OR = 0.347, 95% CI: 0.238-0.506, P < 0.0001; CC vs. TC + TT, OR = 0.675, 95% CI: 0.507-0.898, P = 0.007) might be associated with the risk of AT-DILI.

Conclusions

The polymorphisms of UGT1A1 rs3755319, UGT2B7 rs7662029, and UGT2B7 rs7439366 were significantly associated with AT-DILI susceptibility. However, this conclusion should be interpreted with caution due to the low number of studies and the relatively small sample size.

Quantitative Characterization of Clinically Relevant Drug-Metabolizing Enzymes and Transporters in Rat Liver and Intestinal Segments for Applications in PBPK Modeling

Rats are extensively used as a preclinical model for assessing drug pharmacokinetics (PK) and tissue distribution; however, successful translation of the rat data requires information on the differences in drug metabolism and transport mechanisms between rats and humans. To partly fill this knowledge gap, we quantified clinically relevant drug-metabolizing enzymes and transporters (DMETs) in the liver and different intestinal segments of Sprague-Dawley rats. The levels of DMET proteins in rats were quantified using the global proteomics-based total protein approach (TPA) and targeted proteomics. The abundance of the major DMET proteins was largely comparable using quantitative global and targeted proteomics. However, global proteomics-based TPA was able to detect and quantify a comprehensive list of 66 DMET proteins in the liver and 37 DMET proteins in the intestinal segments of SD rats without the need for peptide standards. Cytochrome P450 (Cyp) and UDP-glycosyltransferase (Ugt) enzymes were mainly detected in the liver with the abundance ranging from 8 to 6502 and 74 to 2558 pmol/g tissue. P-gp abundance was higher in the intestine (124.1 pmol/g) as compared to that in the liver (26.6 pmol/g) using the targeted analysis. Breast cancer resistance protein (Bcrp) was most abundant in the intestinal segments, whereas organic anion transporting polypeptides (Oatp) 1a1, 1a4, 1b2, and 2a1 and multidrug resistance proteins (Mrp) 2 and 6 were predominantly detected in the liver. To demonstrate the utility of these data, we modeled digoxin PK by integrating protein abundance of P-gp and Cyp3a2 into a physiologically based PK (PBPK) model constructed using PK-Sim software. The model was able to reliably predict the systemic as well as tissue concentrations of digoxin in rats. These findings suggest that proteomics-informed PBPK models in preclinical species can allow mechanistic PK predictions in animal models including tissue drug concentrations.

Multiomics Approach Captures Hepatic Metabolic Network Altered by Chronic Ethanol Administration

Using a multiplatform and multiomics approach, we identified metabolites, lipids, proteins, and metabolic pathways that were altered in the liver after chronic ethanol administration. A functional enrichment analysis of the multiomics dataset revealed that rats treated with ethanol experienced an increase in hepatic fatty acyl content, which is consistent with an initial development of steatosis. The nuclear magnetic resonance spectroscopy (NMR) and liquid chromatography-mass spectrometry (LC-MS) metabolomics data revealed that the chronic ethanol exposure selectively modified toxic substances such as an increase in glucuronidation tyramine and benzoyl; and a depletion in cholesterol-conjugated glucuronides. Similarly, the lipidomics results revealed that ethanol decreased diacylglycerol, and increased triacylglycerol, sterol, and cholesterol biosynthesis. An integrated metabolomics and lipidomics pathway analysis showed that the accumulation of hepatic lipids occurred by ethanol modulation of the upstream lipid regulatory pathways, specifically glycolysis and glucuronides pathways. A proteomics analysis of lipid droplets isolated from control EtOH-fed rats and a subsequent functional enrichment analysis revealed that the proteomics data corroborated the metabolomic and lipidomic findings that chronic ethanol administration altered the glucuronidation pathway.

Analysis of Differential Expression Profiles of Liver Cancer Cell Proteins After Treatment with Bile Acid

The pathogenesis of liver cancer has not been fully elucidated yet. Bile acids are components of bile, which are inorganic substances and regulate tumor progression. However, the differential expression profile of liver cancer cell proteins after bile acid treatment remains unclear. Human hepatoma cell line SMMC7721 was cultured and randomly assigned into control group and bile acid group followed by measuring the protein expression profile by protein fingerprinting. SMMC7721 cells were transfected with UGT2B or UGT2B, followed by analysis of UGT2B expression, cell proliferation, apoptosis, migration and PI3K/AKT signaling protein expression. The most obvious proteins with an increased expression after bile acid treatment were UGT2B, AAP, APLP2, LAPTM4B, NCOA4 with UGT2B being the most significant one. Overexpression of UGT2B decreased cell proliferation, promoted cell apoptosis, downregulated migration ability and AKT phosphorylation (P <0.05). UGT2B siRNA transfection significantly down-regulated UGT2B expression, promoted cell proliferation, decreased apoptosis rate, increased migration ability and AKT phosphorylation (P <0.05). In conclusion, bile acid can alter the protein expressions of liver cancer cells, with UGT2B being changed most obviously. UGT2B can affect liver cancer cell behaviors via modulating PI3K/AKT signaling.

PBK Model-Based Prediction of Intestinal Microbial and Host Metabolism of Zearalenone and Consequences for its Estrogenicity

SCOPE

The aim of the present study is to develop physiologically-based kinetic (PBK) models for rat and human that include intestinal microbial and hepatic metabolism of zearalenone (ZEN) in order to predict systemic concentrations of ZEN and to obtain insight in the contribution of metabolism by the intestinal microbiota to the overall metabolism of ZEN.

METHODS AND RESULTS

In vitro derived kinetic parameters, apparent maximum velocities (Vmax ) and Michaelis-Menten constants (Km ) for liver and intestinal microbial metabolism of ZEN are included in the PBK models. The models include a sub-model for the metabolite, α-zearalenol (α-ZEL), a metabolite known to be 60-times more potent as an estrogen than ZEN. Integrating intestinal microbial ZEN metabolism into the PBK models revealed that hepatic metabolism drives the formation of α-ZEL. Furthermore, the models predicted that at the tolerable daily intake (TDI) of 0.25 µg kg-1 bw the internal concentration of ZEN and α-ZEL are three-orders of magnitude below concentrations reported to induce estrogenicity in vitro.

CONCLUSION

It is concluded that combining kinetic data on liver and intestinal microbial metabolism in a PBK model facilitates a holistic view on the role of the intestinal microbiota in the overall metabolism of the foodborne xenobiotic ZEN and its bioactivation to α-ZEL.

Absorption, metabolism and bioavailability of flavonoids: a review

Flavonoids are stored in various plants and widely presented in different kinds of food in variable amounts. Plant roots, stems, leaves, flowers and fruits are known to have high amounts of flavonoids. However, flavonoid aglycones are found less frequently in natural products, as it requires bioconversion through bacteria, which provide β-glucosidase to convert them. Recently, flavonoids and its metabolites were applied in the prevention and treatment of various diseases such as cancers, obesity, diabetes, hypertension, hyperlipidemia, cardiovascular diseases, neurological disorders and osteoporosis in numerous studies. This review focused on absorption, activity, metabolism, and bioavailability of flavonoids. Also authors organized and collected newly-found reports of flavonoids and their absorption barriers of flavonoids in the gastrointestinal tract, providing the latest findings and evidence from the past decade. Particularly, nanoparticles delivery systems are emphasized regarding fabrication methods and their potential benefits on flavonoids. Moreover, the potential challenges of nanoparticles as delivery system for flavonoids in the gastrointestinal tract are also discussed.

In vitro glucuronidation of bisphenol A in liver and intestinal microsomes: interspecies differences in humans and laboratory animals

Bisphenol A (BPA) is an endocrine-disrupting chemical, and is predominantly metabolized into glucuronide in mammals. The present study was conducted in order to examine the hepatic and intestinal glucuronidation of BPA in humans and laboratory animals such as monkeys, dogs, rats, and mice in an in vitro system using microsomal fractions. K_m, V_max, and CL_int values in human liver microsomes were 7.54 µM, 17.7 nmol/min/mg protein, and 2.36 mL/min/mg protein, respectively. CL_int values in liver microsomes of monkey, dogs, rats, and mice were 1.5-, 2.4-, 1.7- and 8.2-fold that of humans, respectively. In intestinal microsomes, K_m, V_max, and CL_int values in humans were 39.3 µM, 0.65 nmol/min/mg protein, and 0.02 mL/min/mg protein, respectively. The relative levels of CL_int in monkey, dogs, rats, and mice to that of humans were 7.0-, 12-, 34-, and 29-fold, respectively. Although CL_int values were higher in liver microsomes than in intestinal microsomes in all species, and marked species difference in the ratio of liver to intestinal microsomes was observed as follows: humans, 118; monkeys, 25; dogs, 23; rats, 5.9; mice, 33. These results suggest that the functional roles of UDP-glucuronosyltransferase (UGT) enzymes expressed in the liver and intestines in the metabolism of BPA extensively differ among humans, monkeys, dogs, rats, and mice.

Comparative assessment for rat strain differences in metabolic profiles of 14 drugs in Wistar Han and Sprague Dawley hepatocytes

Knowledge of inter-strain and inter-gender differences in drug metabolism studies is important for animal selection in pharmacokinetic and toxicological studies. The effects of rat strain and gender in in vitro metabolism were investigated in Sprague Dawley (SD) and Wister Han (WH) rats based on the hepatocyte metabolic profiles of 14 small molecule drugs. Similarities were found between the hepatocyte metabolic clearances of SD and WH strains, suggesting that only one strain can be confidently used for the evaluation of hepatic clearance. Neither strain of rat was preferable over the other to cover human metabolites. Higher similarities in metabolic pathways were found between the same gender than the same strain. Differences in metabolite identities, metabolite formation rates and potential biotransformation pathways were observed between SD and WH rat strains. Eleven metabolites from six drugs were "disproportionally" formed between SD and WH rats. The use of a specific rat strain model and gender for ADME and toxicity testing should, therefore, be carefully considered as metabolic profiles may differ, even though metabolic clearance was similar between SD and WH rats.

Wogonin glucuronidation in liver and intestinal microsomes of humans, monkeys, dogs, rats, and mice

Wogonin, one of the flavonoids isolated from Scutellaria baicalensis, exhibits some beneficial bioactivities, including anti-inflammatory and anticancer effects, and is metabolized into glucuronide by UDP-glucuronosyltransferase (UGT) enzymes in humans. In the present study, wogonin glucuronidation was examined in the liver and intestinal microsomes of humans, monkeys, dogs, rats, and mice using a kinetic analysis.The kinetics of wogonin glucuronidation by liver microsomes followed the biphasic model in all species examined. CL_int values (x-intercept) based on v versus V/[S] plots were rats > humans ≈ monkeys > mice > dogs. The kinetics of intestinal microsomes fit the Michaelis-Menten model for humans, monkeys, rats, and mice and the substrate inhibition model for dogs. CL_int values were rats > monkeys > mice > dogs > humans. The tissue dependence of CL_int values was liver microsomes > intestinal microsomes for humans, dogs, and rats, and liver microsomes ≈ intestinal microsomes for monkeys and mice.These results demonstrated that the metabolic abilities of UGT enzymes toward wogonin in the liver and intestines markedly differ among humans, monkeys, dogs, rats, and mice, and suggest that species differences are closely associated with the biological effects of wogonin.

Glucuronidation as a metabolic barrier against zearalenone in rat everted intestine

Zearalenone (ZON), produced by Fusarium fungi, exhibits estrogenic activity. Livestock can be exposed to ZON orally through contaminating feeds such as cereals, leading to reproductive disorders such as infertility and miscarriage via endocrine system disruption. However, the details of ZON metabolism remain unclear, and the mechanism of its toxicity has not been fully elucidated. In this study, we investigated the kinetics of ZON absorption and metabolism in rat segmented everted intestines. ZON absorption was confirmed in each intestine segment 60 min after application to the mucosal buffer at 10 µM. Approximately half of the absorbed ZON was metabolized to α-zearalenol, which tended to be mainly glucuronidated in intestinal cells. In the proximal intestine, most of the glucuronide metabolized by intestinal cells was excreted to the mucosal side, suggesting that the intestine plays an important role as a first drug metabolism barrier for ZON. However, in the distal intestine, ZON metabolites tended to be transported to the serosal side. Glucuronide transported to the serosal side could be carried via the systemic circulation to the local tissues, where it could be reactivated by deconjugation. These results are important with regard to the mechanism of endocrine disruption caused by ZON.

A compartmental approach to isosteviol's disposition in Sprague-Dawley rats

Isosteviol has been reported to reverse hypertrophy and related inflammatory responses in in vitro models representative of cardiac muscle cells. The disposition of isosteviol is, however, characterized by secondary peaks and long plasma residence time despite reports of a relatively short half-life in liver fractions. The present study describes a compartmental approach to modelling the secondary peaks characteristic of isosteviol's concentration-time data in Sprague-Dawley rats. Oral (4 mg/kg) and intravenous (4 mg/kg) doses of isosteviol were administered to male and female Sprague-Dawley rats. Plasma samples collected between 0 and 72 h, and total bile secreted in 24 h, were analysed for isosteviol content with LC-MS/MS techniques. The disposition of isosteviol was, thereafter, described with a structural model that accounted for the sampling, liver and biliary secretion compartments, with a gap-time characterizing the accumulation and subsequent emptying of isosteviol for re-absorption. The half-life of isosteviol following oral dosing was about 103% greater in female rats than in the male, and the model-derived area under the concentration-time curve (AUC) in 72 h was about 756% greater in female animals than in males. Following the administration of intravenous doses of isosteviol, half-life and AUC in 24 h were about 332% and 595%, respectively, higher in female rats than in males. Isosteviol equivalent secreted into bile over 24 h accounted for about 94% of orally administered dose in male rats, and about 59% of oral dose in females. These findings show a differential systemic removal of isosteviol in Sprague-Dawley rats, likely explainable by gender-related differences in the glucuronidation-capacity of isosteviol.

S-equol glucuronidation in liver and intestinal microsomes of humans, monkeys, dogs, rats, and mice

S-equol, an active metabolite of the soy isoflavone daidzein, is mainly metabolized into glucuronide(s) by UDP-glucuronosyltransferase (UGT) enzymes in mammals. In the present study, S-equol glucuronidation was examined in the liver and intestinal microsomes of humans, monkeys, dogs, rats, and mice using a kinetic analysis. CL_int values for 7- and 4'-glucuronidation by liver microsomes were higher than those by intestinal microsomes in all species. CL_int values for total glucuronidation (sum of 7- and 4'-glucuronidation) were rats (7.6) > monkeys (5.8) > mice (4.9) > dogs (2.8) > humans (1.0) for liver microsomes, and rats (9.6) > mice (2.8) > dogs (1.3) ≥ monkeys (1.2) > humans (1.0) for intestinal microsomes, respectively. Regarding regioselective glucuronidation by liver and intestinal microsomes, CL_int values were 7-glucuronidation > 4'-glucuronidation for humans, monkeys, dogs, and mice, and 4'-glucuronidation > 7-glucuronidation for rats. These results suggest that the metabolic abilities of UGT enzymes toward S-equol in the liver and intestines markedly differ among humans, monkeys, dogs, rats, and mice.